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Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Focused ion beam source method and apparatus  

DOE Patents [OSTI]

A focused ion beam having a cross section of submicron diameter, a high ion current, and a narrow energy range is generated from a target comprised of particle source material by laser ablation. The method involves directing a laser beam having a cross section of critical diameter onto the target, producing a cloud of laser ablated particles having unique characteristics, and extracting and focusing a charged particle beam from the laser ablated cloud. The method is especially suited for producing focused ion beams for semiconductor device analysis and modification.

Pellin, Michael J. (Naperville, IL); Lykke, Keith R. (Gaithersburg, MD); Lill, Thorsten B. (Sunnyvale, CA)

2000-01-01T23:59:59.000Z

2

Focused ion beam micromilling and articles therefrom  

DOE Patents [OSTI]

An ultrahigh vacuum focused ion beam micromilling apparatus and process are isclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters.

Lamartine, Bruce C. (Los Alamos, NM); Stutz, Roger A. (Los Alamos, NM)

1998-01-01T23:59:59.000Z

3

Focused ion beam micromilling and articles therefrom  

DOE Patents [OSTI]

An ultrahigh vacuum focused ion beam micromilling apparatus and process are disclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters. 6 figs.

Lamartine, B.C.; Stutz, R.A.

1998-06-30T23:59:59.000Z

4

Development of a focused ion beam micromachining system  

SciTech Connect (OSTI)

Focused ion beams are currently being investigated for many submicron fabrication and analytical purposes. An FIB micromachining system consisting of a UHV vacuum system, a liquid metal ion gun, and a control and data acquisition computer has been constructed. This system is being used to develop nanofabrication and nanomachining techniques involving focused ion beams and scanning tunneling microscopes.

Pellerin, J.G.; Griffis, D.; Russell, P.E.

1988-12-01T23:59:59.000Z

5

Characterization of ionic liquid ion sources for focused ion beam applications  

E-Print Network [OSTI]

In the Focused Ion Beam (FIB) technique, a beam of ions is reduced to nanometer dimensions using dedicated optics and directed to a substrate for patterning. This technique is widely used in micro- and nanofabrication for ...

Perez Martinez, Carla S. (Carla Sofia)

2013-01-01T23:59:59.000Z

6

Ultrahigh vacuum focused ion beam micromill and articles therefrom  

DOE Patents [OSTI]

An ultrahigh vacuum focused ion beam micromilling apparatus and process are disclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters. 6 figs.

Lamartine, B.C.; Stutz, R.A.

1998-02-24T23:59:59.000Z

7

Ultrahigh vacuum focused ion beam micromill and articles therefrom  

DOE Patents [OSTI]

An ultrahigh vacuum focused ion beam micromilling apparatus and process are isclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters.

Lamartine, Bruce C. (Los Alamos, NM); Stutz, Roger A. (Los Alamos, NM)

1998-01-01T23:59:59.000Z

8

Focused Ion Beam Induced Effects on MOS Transistor Parameters  

SciTech Connect (OSTI)

We report on recent studies of the effects of 50 keV focused ion beam (FIB) exposure on MOS transistors. We demonstrate that the changes in value of transistor parameters (such as threshold voltage, V{sub t}) are essentially the same for exposure to a Ga+ ion beam at 30 and 50 keV under the same exposure conditions. We characterize the effects of FIB exposure on test transistors fabricated in both 0.5 {micro}m and 0.225 {micro}m technologies from two different vendors. We report on the effectiveness of overlying metal layers in screening MOS transistors from FIB-induced damage and examine the importance of ion dose rate and the physical dimensions of the exposed area.

Abramo, Marsha T.; Antoniou, Nicholas; Campbell, Ann N.; Fleetwood, Daniel M.; Hembree, Charles E.; Jessing, Jeffrey R.; Soden, Jerry M.; Swanson, Scot E.; Tangyunyong, Paiboon; Vanderlinde, William E.

1999-07-28T23:59:59.000Z

9

Laser-Cooled Lithium Atoms: A New Source for Focused Ion Beams  

E-Print Network [OSTI]

Laser-Cooled Lithium Atoms: A New Source for Focused Ion Beams P R O J E C T L E A D E R : Jabez Mc) to provide ions for a focused ion beam (FIB) capable of non-destructive imaging. K E Y A C C O M P L I S H M mounted on a commercial focused ion beam system, creating the world's first lithium ion microscope

10

Process Considerations and Failure Analysis using Focused Ion Beam Milling  

E-Print Network [OSTI]

novel method of connecting two adjacent lines on the same level of metallization in integrated circuits using a laser was previously developed with programmable gate array applications and customized chips in mind. This work reports a study of failure mechanisms in the laser linking process. Experiments relating critical processing parameters (laser power and target alignment) to the visual failure modes were performed. A Focused Ion Beam (FIB) was used to cross-section and image failed links. The images were compared with previously published linking models. Finite element analysis was used to simulate laser absorption and subsequent thermal diffusion, and to justify a simple model defining the process window for laser linking. The research correlated theoretical predictions

Roy L. Rasera; Certifie Dr; Joseph B. Bernstein; Roy L. Rasera

1995-01-01T23:59:59.000Z

11

Solenoidal Fields for Ion Beam Transport and Focusing  

SciTech Connect (OSTI)

In this report we calculate time-independent fields of solenoidal magnets that are suitable for ion beam transport and focusing. There are many excellent Electricity and Magnetism textbooks that present the formalism for magnetic field calculations and apply it to simple geometries [1-1], but they do not include enough relevant detail to be used for designing a charged particle transport system. This requires accurate estimates of fringe field aberrations, misaligned and tilted fields, peak fields in wire coils and iron, external fields, and more. Specialized books on magnet design, technology, and numerical computations [1-2] provide such information, and some of that is presented here. The AIP Conference Proceedings of the US Particle Accelerator Schools [1-3] contain extensive discussions of design and technology of magnets for ion beams - except for solenoids. This lack may be due to the fact that solenoids have been used primarily to transport and focus particles of relatively low momenta, e.g. electrons of less than 50 MeV and protons or H- of less than 1.0 MeV, although this situation may be changing with the commercial availability of superconducting solenoids with up to 20T bore field [1-4]. Internal reports from federal laboratories and industry treat solenoid design in detail for specific applications. The present report is intended to be a resource for the design of ion beam drivers for Inertial Fusion Energy [1-5] and Warm Dense Matter experiments [1-6], although it should also be useful for a broader range of applications. The field produced by specified currents and material magnetization can always be evaluated by solving Maxwell's equations numerically, but it is also desirable to have reasonably accurate, simple formulas for conceptual system design and fast-running beam dynamics codes, as well as for general understanding. Most of this report is devoted to such formulas, but an introduction to the Tosca{copyright} code [1-7] and some numerical results obtained with it are also presented. Details of design, fabrication, installation, and operation of magnet systems are not included; here we are concerned with calculations that precede or supplement detailed design. Mathematical derivations are presented with only a moderate number of steps. While there is no claim of originality, except for various numerical approximations and a conceptual induction module design in section 20, many of the results and discussions are not readily available elsewhere. Our primary topic is axisymmetric solenoidal systems with no magnetic materials. These simplifying features allow useful analytical calculations, which occupy sections 2-13. Deviations from axisymmetry are considered in sections 14, 15, 21, 22, and 23 and the effects of magnetic materials are treated in sections 16-20. Since magnetic aberrations are mixed with geometric aberrations in computing ion orbits, section 22 on the ion equations of motion in an arbitrary field is included.

Lee, Edward P.; Leitner, Matthaeus

2007-11-01T23:59:59.000Z

12

Direct-write milling of diamond by a focused oxygen ion beam  

E-Print Network [OSTI]

Recent advances in focused ion beam technology have enabled high-resolution, direct-write nanofabrication using light ions. Studies with light ions to date have, however, focused on milling of materials where sub-surface ion beam damage does not inhibit device performance. Here we report on direct-write milling of single crystal diamond using a focused beam of oxygen ions. Material quality is assessed by Raman and luminescence analysis, and reveals that the damage layer generated by oxygen ions can be removed by nonintrusive post-processing methods such as localised electron beam induced chemical etching.

Martin, Aiden A; Botman, Aurelien; Toth, Milos; Aharonovich, Igor

2015-01-01T23:59:59.000Z

13

Focused ion beam damage to MOS integrated circuits  

SciTech Connect (OSTI)

Commercial focused ion beam (FIB) systems are commonly used to image integrated circuits (ICS) after device processing, especially in failure analysis applications. FIB systems are also often employed to repair faults in metal lines for otherwise functioning ICS, and are being evaluated for applications in film deposition and nanofabrication. A problem that is often seen in FIB imaging and repair is that ICS can be damaged during the exposure process. This can result in degraded response or out-right circuit failure. Because FIB processes typically require the surface of an IC to be exposed to an intense beam of 30--50 keV Ga{sup +} ions, both charging and secondary radiation damage are potential concerns. In previous studies, both types of effects have been suggested as possible causes of device degradation, depending on the type of device examined and/or the bias conditions. Understanding the causes of this damage is important for ICS that are imaged or repaired by a FIB between manufacture and operation, since the performance and reliability of a given IC is otherwise at risk in subsequent system application. In this summary, the authors discuss the relative roles of radiation damage and charging effects during FIB imaging. Data from exposures of packaged parts under controlled bias indicate the possibility for secondary radiation damage during FIB exposure. On the other hand, FIB exposure of unbiased wafers (a more common application) typically results in damage caused by high-voltage stress or electrostatic discharge. Implications for FIB exposure and subsequent IC use are discussed.

FLEETWOOD,D.M.; CAMPBELL,ANN N.; HEMBREE,CHARLES E.; TANGYUNYONG,PAIBOON; JESSING,JEFFREY R.; SODEN,JERRY M.

2000-05-10T23:59:59.000Z

14

FINAL FOCUS ION BEAM INTENSITY FROM TUNGSTEN FOIL CALORIMETER AND SCINTILLATOR IN NDCX-I  

E-Print Network [OSTI]

FOCUS ION BEAM INTENSITY FROM TUNGSTEN FOIL CALORIMETER ANDtemperature rise in the tungsten foil. A cross-calibrationis obtained with a 3µm thick tungsten foil calorimeter and

Lidia, S.M.

2010-01-01T23:59:59.000Z

15

Rare earth focused ion beam implantation utilizing Er and Pr liquid alloy ion sources  

E-Print Network [OSTI]

Pr,10,11 Eu,12 Dy,13 Er,13­15 and Tm16 doped GaN. Rare earth elements were added during growthRare earth focused ion beam implantation utilizing Er and Pr liquid alloy ion sources L. C. Chao, B write implantation. © 1999 American Vacuum Society. S0734-211X 99 08306-7 I. INTRODUCTION Rare earth

Steckl, Andrew J.

16

Controlled formation of nanoscale wrinkling patterns on polymers using focused ion beam  

E-Print Network [OSTI]

2007 It has previously been shown that focused ion beam irradiation induces a wrinkled skin­10]. Other potential appli- cations include optical diffraction gratings and optical microlenses [11 is constrained by the PDMS substrate, the skin experiences in-plane compressive strain upon ion beam irradiation

Hutchinson, John W.

17

Diagnostics of ion beam generated from a Mather type plasma focus device  

SciTech Connect (OSTI)

Diagnostics of ion beam emission from a 3 kJ Mather-type plasma focus device have been performed for deuterium discharge at low pressure regime. Deuterium plasma focus was found to be optimum at pressure of 0.2 mbar. The energy spectrum and total number of ions per shot from the pulsed ion beam are determined by using biased ion collectors, Faraday cup, and solid state nuclear track detector CR-39. Average energy of the ion beam obtained is about 60 keV. Total number of the ions has been determined to be in the order of 10{sup 11} per shot. Solid state nuclear track detectors (SSNTD) CR39 are employed to measure the particles at all angular direction from end on (0°) to side on (90°). Particle tracks are registered by SSNTD at 30° to 90°, except the one at the end-on 0°.

Lim, L. K., E-mail: yapsl@um.edu.my; Ngoi, S. K., E-mail: yapsl@um.edu.my; Wong, C. S., E-mail: yapsl@um.edu.my; Yap, S. L., E-mail: yapsl@um.edu.my [Plasma Technology Research Centre, Department of Physics, Faculty of Science, University of Malaya (Malaysia)

2014-03-05T23:59:59.000Z

18

Large Area Microcorrals and Cavity Formation on Cantilevers using a Focused Ion Beam  

SciTech Connect (OSTI)

We utilize focused ion beam (FIB) to explore various sputtering parameters to form large area microcorrals and cavities on cantilevers. Microcorrals were rapidly created by modifying ion beam blur and overlaps. Modification in FIB sputtering parameters affects the periodicity and shape of corral microstructure. Cantilever deflections show ion beam amorphization effects as a function of sputtered area and cantilever base cavities with or without side walls. The FIB sputtering parameters address a method for rapid creation of a cantilever tensiometer with integrated fluid storage and delivery.

Saraf, Laxmikant V.; Britt, David W.

2011-09-14T23:59:59.000Z

19

Plasma focus ion beam fluence and flux—For various gases  

SciTech Connect (OSTI)

A recent paper derived benchmarks for deuteron beam fluence and flux in a plasma focus (PF) [S. Lee and S. H. Saw, Phys. Plasmas 19, 112703 (2012)]. In the present work we start from first principles, derive the flux equation of the ion beam of any gas; link to the Lee Model code and hence compute the ion beam properties of the PF. The results show that, for a given PF, the fluence, flux, ion number and ion current decrease from the lightest to the heaviest gas except for trend-breaking higher values for Ar fluence and flux. The energy fluence, energy flux, power flow, and damage factors are relatively constant from H{sub 2} to N{sub 2} but increase for Ne, Ar, Kr and Xe due to radiative cooling and collapse effects. This paper provides much needed benchmark reference values and scaling trends for ion beams of a PF operated in any gas.

Lee, S. [Centre for Plasma Research, INTI International University, 71800 Nilai (Malaysia) [Centre for Plasma Research, INTI International University, 71800 Nilai (Malaysia); Institute for Plasma Focus Studies, 32 Oakpark Drive, Chadstone 3148 (Australia); Physics Department, University of Malaya (Malaysia); Saw, S. H. [Centre for Plasma Research, INTI International University, 71800 Nilai (Malaysia) [Centre for Plasma Research, INTI International University, 71800 Nilai (Malaysia); Institute for Plasma Focus Studies, 32 Oakpark Drive, Chadstone 3148 (Australia)

2013-06-15T23:59:59.000Z

20

Site-controlled fabrication of Ga nanodroplets by focused ion beam  

SciTech Connect (OSTI)

Ga droplets are created by focused ion beam irradiation of GaAs surface. We report that ordered Ga droplets can be formed on the GaAs surface without any implantation damage. The droplets are characterized with bigger sizes than those droplets formed on damaged area. These aligned Ga droplets are formed via the migration of Ga atoms from ion irradiation area to the edge of undamaged GaAs surface and further nucleation into droplets. The morphological evolution and size distribution of these nanodroplets are investigated systematically with different beam irradiation time and incident angles. Based on this method, well positioned Ga nanodroplets, such as chains, are achieved by using focus ion beam patterning. The controllable assembly of droplets on undamaged semiconductor surface can be used to fabricate templates, to fabricate quantum structures and quantum devices by droplet epitaxy technique.

Xu, Xingliang; Wang, Zhiming M., E-mail: zhmwang@gmail.com [State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083 (China); Wu, Jiang; Li, Handong; Zhou, Zhihua [State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Wang, Xiaodong [Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083 (China)

2014-03-31T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Focused ion beam specimen preparation for electron holography of electrically biased thin film solar cells  

E-Print Network [OSTI]

, biased TEM specimen, thin film solar cell, FIB Thin films of hydrogenated Si (Si:H) can be used as active for electron holography of a thin film solar cell using conventional lift-out specimen preparation and a homeFocused ion beam specimen preparation for electron holography of electrically biased thin film

Dunin-Borkowski, Rafal E.

22

Focused Ion Beam Production Using a Pyroelectric Crystal and a Resistive Glass Tube  

E-Print Network [OSTI]

Focused Ion Beam Production Using a Pyroelectric Crystal and a Resistive Glass Tube T. Z. Fullem, A to accelerate electrons into a metal target has led to the production of compact X-Ray generators [4], [5], [6 tungsten tip (marketed for use in a scanning electron microscope) with an apex radius of 70 nm was mounted

Danon, Yaron

23

Performance predictions for a laser intensified thermal beam for use in high resolution Focused Ion Beam instruments  

E-Print Network [OSTI]

Photo-ionization of a laser-cooled and compressed atomic beam from a high-flux thermal source can be used to create a high-brightness ion beam for use in Focus Ion Beam (FIB) instruments. Here we show using calculations and Doppler cooling simulations that an atomic rubidium beam with a brightness of $2.1 \\times 10^7 A/(m^2\\,sr\\,eV)$ at a current of 1 nA can be created using a compact 5 cm long 2D magneto-optical compressor which is more than an order of magnitude better than the current state of the art Liquid Metal Ion Source.

Wouters, S H W; Notermans, R P M J W; Debernardi, N; Mutsaers, P H A; Luiten, O J; Vredenbregt, E J D

2014-01-01T23:59:59.000Z

24

H-mode accelerating structures with PMQ focusing for low-beta ion beams  

SciTech Connect (OSTI)

We are developing high-efficiency normal-conducting RF accelerating structures based on inter-digital H-mode (IH) cavities and the transverse beam focusing with permanent-magnet quadrupoles (PMQ), for beam velocities in the range of a few percent of the speed of light. Such IH-PMQ accelerating structures following a short RFQ can be used in the front end of ion linacs or in stand-alone applications, e.g. a compact deuteron-beam accelerator up to the energy of several MeV. Results of combined 3-D modeling for a full IH-PMQ accelerator tank - electromagnetic computations, beam-dynamics simulations with high currents, and thermal-stress analysis - are presented. The accelerating field profile in the tank is tuned to provide the best beam propagation using coupled iterations of electromagnetic and beam-dynamics modeling. A cold model of the IH-PMQ tank is being manufactured.

Kurennoy, Sergey S [Los Alamos National Laboratory; O' Hara, James F [Los Alamos National Laboratory; Olivas, Eric R [Los Alamos National Laboratory; Rybarcyk, Lawrence J [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

25

Micromilling of Metal Alloys with Focused Ion Beam-Fabricated Tools  

SciTech Connect (OSTI)

This work combines focused ion beam sputtering and ultra-precision machining as a first step in fabricating microstructure in metals and alloys. Specifically, {approx}25{micro}m diameter micro-end mills are made from cobalt M42 high-speed steel and C2 micrograin tungsten carbide tool blanks by ion beam sputtering. A 20 keV focused gallium beam defines tool cutting edges having radii of curvature < 0.1{micro}m. Micro-end mills having 2, 4 and 5 cutting edges successfully machine small trenches in 6061-T4 aluminum, brass, 4340 steel and polymethyl methacrylate. Machined trench widths are approximately equal to the tool diameters and surface roughnesses (rms) are {approx}150 nm or less. Microtools are robust and operate for more than 6 hours without fracture. Results from ultra-precision machining aluminum at feed rates as high as 50 mm/minute are included.

ADAMS,DAVID P.; VASILE,M.J.; BENAVIDES,GILBERT L.; CAMPBELL,ANN N.

1999-11-05T23:59:59.000Z

26

Self-focusing of a Gaussian electromagnetic beam in a multi-ions plasma  

SciTech Connect (OSTI)

In this paper, the authors have developed a formulation for the dependence of electron and ion densities on the irradiance of an electromagnetic beam in a plasma with multiply charged ions, corresponding to collisional, ponderomotive, and relativistic-ponderomotive nonlinearities and different electron/ion temperatures; consequently, the corresponding expressions for the electron density modification in the presence of an electromagnetic (em) field have been derived. Paraxial approach in the vicinity of intensity maximum has been adopted to analyze the propagation characteristics of an em beam in such plasmas; on the basis of this analysis, critical curves and self-focusing curves have been computed numerically and graphically illustrated. For a numerical appreciation of the analysis, we have specifically carried out the computations for the simultaneous presence of singly and doubly charged ions in the plasma. As an important outcome, it is seen that the nonlinear effects (and hence self-focusing) get suppressed in the presence of multiply ionized ions; the conditions for the three modes of em-beam propagation viz. oscillatory focusing/defocusing and steady divergence have been discussed.

Misra, Shikha; Sodha, M. S. [Centre of Energy Studies, Indian Institute of Technology Delhi (IITD), New Delhi 110016 (India)] [Centre of Energy Studies, Indian Institute of Technology Delhi (IITD), New Delhi 110016 (India); Mishra, S. K. [Institute for Plasma Research (IPR), Gandhinagar 382428 (India)] [Institute for Plasma Research (IPR), Gandhinagar 382428 (India)

2013-10-15T23:59:59.000Z

27

Enhanced Self-Focusing of an Ion Beam Pulse Propagating through a Background Plasma along a Solenoidal Magnetic Field  

E-Print Network [OSTI]

Enhanced Self-Focusing of an Ion Beam Pulse Propagating through a Background Plasma along.58.Lq, 52.59.Ã?f Neutralization and focusing of charged particle beam pulses by a background plasma form plasma elec- trons. The effects of the enhanced self-focusing are of particular importance

Kaganovich, Igor

28

Percolation of gallium dominates the electrical resistance of focused ion beam deposited metals  

SciTech Connect (OSTI)

Metal deposition through focused ion beam (FIB) based systems is thought to result in material composed of the primary metal from the metallo-organic precursor in addition to carbon, oxygen, and gallium. We determined, through electrical resistance and chemical composition measurements on a wide range of FIB deposited platinum and tungsten lines, that the gallium ion (Ga{sup +}) concentration in the metal lines plays the dominant role in controlling the electrical resistivity. Effective medium theory, based on McLachlan's formalisms, was used to describe the relationship between the Ga{sup +} concentration and the corresponding resistivity.

Faraby, H. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States); DiBattista, M. [Qualcomm Technologies Incorporated, San Diego, California 92121 (United States); Bandaru, P. R., E-mail: pbandaru@ucsd.edu [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093 (United States)

2014-04-28T23:59:59.000Z

29

Induced Optical Losses in Optoelectronic Devices due to Focused Ion Beam Damages  

E-Print Network [OSTI]

A study of damages caused by gallium focused ion beam (FIB) into III-V compounds is presented. Potential damages caused by local heating, ion implantation, and selective sputtering are presented. Preliminary analysis shows that local heating is negligible. Gallium implantation is shown to occur over areas tens of nanometers thick. Gallium accumulation as well as selective sputtering during III-V compounds milling is expected. Particularly, for GaAs, this effect leads to gallium segregation and formation of metallic clusters. Microdisk resonators were fabricated using FIB milling with different emission currents to analyze these effects on a device. It is shown that for higher emission current, thus higher implantation doses, the cavity quality factor rapidly decreases due to optical scattering losses induced by implanted gallium atoms.

Vallini, Felipe; Reis, Elohim Fonseca dos; von Zuben, Antônio Augusto; Frateschi, Newton Cesário

2012-01-01T23:59:59.000Z

30

Implementation of focused ion beam (FIB) system in characterization of nuclear fuels and materials  

SciTech Connect (OSTI)

Beginning in 2007, a program was established at the Idaho National Laboratory to update key capabilities enabling microstructural and micro-chemical characterization of highly irradiated and/or radiologically contaminated nuclear fuels and materials at scales that previously had not been achieved for these types of materials. Such materials typically cannot be contact handled and pose unique hazards to instrument operators, facilities, and associated personnel. One of the first instruments to be acquired was a Dual Beam focused ion beam (FIB)-scanning electron microscope (SEM) to support preparation of transmission electron microscopy and atom probe tomography samples. Over the ensuing years, techniques have been developed and operational experience gained that has enabled significant advancement in the ability to characterize a variety of fuel types including metallic, ceramic, and coated particle fuels, obtaining insights into in-reactor degradation phenomena not obtainable by any other means. The following article describes insights gained, challenges encountered, and provides examples of unique results obtained in adapting Dual Beam FIB technology to nuclear fuels characterization.

A. Aitkaliyeva; J. W. Madden; B. D. Miller; J I Cole; T A Hyde

2014-10-01T23:59:59.000Z

31

Enhanced collective focusing of intense neutralized ion beam pulses in the presence of weak solenoidal magnetic fields  

SciTech Connect (OSTI)

The design of ion drivers for warm dense matter and high energy density physics applications and heavy ion fusion involves transverse focusing and longitudinal compression of intense ion beams to a small spot size on the target. To facilitate the process, the compression occurs in a long drift section filled with a dense background plasma, which neutralizes the intense beam self-fields. Typically, the ion bunch charge is better neutralized than its current, and as a result a net self-pinching (magnetic) force is produced. The self-pinching effect is of particular practical importance, and is used in various ion driver designs in order to control the transverse beam envelope. In the present work we demonstrate that this radial self-focusing force can be significantly enhanced if a weak (B {approx} 100 G) solenoidal magnetic field is applied inside the neutralized drift section, thus allowing for substantially improved transport. It is shown that in contrast to magnetic self-pinching, the enhanced collective self-focusing has a radial electric field component and occurs as a result of the overcompensation of the beam charge by plasma electrons, whereas the beam current becomes well-neutralized. As the beam leaves the neutralizing drift section, additional transverse focusing can be applied. For instance, in the neutralized drift compression experiments (NDCX) a strong (several Tesla) final focus solenoid is used for this purpose. In the present analysis we propose that the tight final focus in the NDCX experiments may possibly be achieved by using a much weaker (few hundred Gauss) magnetic lens, provided the ion beam carries an equal amount of co-moving neutralizing electrons from the preceding drift section into the lens. In this case the enhanced focusing is provided by the collective electron dynamics strongly affected by a weak applied magnetic field.

Dorf, Mikhail A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Davidson, Ronald C.; Kaganovich, Igor D.; Startsev, Edward A. [Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

2012-05-15T23:59:59.000Z

32

Generation, transport and focusing of high-brightness heavy ion beams  

E-Print Network [OSTI]

The Neutralized Transport Experiment (NTX) has been built at the Heavy Ion Fusion Virtual National Laboratory. NTX is the first successful integrated beam system experiment that explores various physical phenomena, and ...

Henestroza, Enrique

2006-01-01T23:59:59.000Z

33

FINAL FOCUS ION BEAM INTENSITY FROM TUNGSTEN FOIL CALORIMETER AND SCINTILLATOR IN NDCX-I  

SciTech Connect (OSTI)

Laboratory high energy density experiments using ion beam drivers rely upon the delivery of high-current, high-brightness ion beams with high peak intensity onto targets. Solid-state scintillators are typically used to measure the ion beam spatial profile but they display dose-dependent degradation and aging effects. These effects produce uncertainties and limit the accuracy of measuring peak beam intensities delivered to the target. For beam tuning and characterizing the incident beam intensity, we have developed a cross-calibrating diagnostic suite that extends the upper limit of measurable peak intensity dynamic range. Absolute intensity calibration is obtained with a 3 {micro}m thick tungsten foil calorimeter and streak spectrometer. We present experimental evidence for peak intensity measures in excess of 400 kW/cm{sup 2} using a 0.3 MV, 25 mA, 5-20 {micro}sec K{sup +1} beam. Radiative models and thermal diffusion effects are discussed because they affect temporal and spatial resolution of beam intensity profiles.

Lidia, S.M.; Bieniosek, F.; Henestroza, E.; Ni, P.; Seidl, P.

2010-04-30T23:59:59.000Z

34

Glass nanoimprint using amorphous Ni-P mold etched by focused-ion beam  

SciTech Connect (OSTI)

The authors succeeded in glass-nanoimprint lithography of micropatterns and nanopatterns using an amorphous Ni-P alloy mold. Glasslike carbon has been used as a mold material to mold not only Pyrex glass but also quartz, because it is still stable at a temperature of 1650 deg. C. However, it is difficult to process glasslike carbon substrates into arbitrary shapes by machining. They thought that amorphous Ni-P alloy could be used as a mold material for industrial glass molding. If Ni is electroless plated when mixed with suitable amount of P on a Si wafer, the Ni-P alloy layer becomes amorphous. An appropriate ratio of Ni and P was determined by the results of x-ray-diffraction measurements. The optimized composition ratio of Ni-P was Ni:P=92:8 wt %. Moreover, line and space patterns and dot arrays with linewidths of as little as 500 nm were etched on the mold using focused-ion beam (FIB) and the processing accuracy for the amorphous Ni-P layer was compared with that for the pure Ni layer. The result was that patterns of 500 nm width were etched to a depth of 2 {mu}m on an amorphous Ni-P alloy mold and the processed surfaces were smooth. In contrast, in the case of the pure Ni layer, the processing line was notched and the sidewalls were very rough. The crystal grain seems to hinder the processing of the nanopattern. After FIB etching, the amorphous Ni-P alloy was thermally treated at 400 deg. C to improve the hardness. Finally, line and space patterns and dot arrays on the amorphous Ni-P alloy mold were nanoimprinted on Pyrex glass using a glass-nanoimprint system (ASHE0201) that National Institute of Advanced Industrial Science and Technology developed.

Mekaru, Harutaka; Kitadani, Takeshi; Yamashita, Michiru; Takahashi, Masaharu [National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1, Namiki, Tsukuba, Ibaraki 305-8564 (Japan); SAWA Plating Co., Ltd., 753 Hoshiro, Himeji, Hyogo 670-0804 (Japan); Hyogo Prefectural Institute of Technology, 3-1-12 Yukihira-cho, Suma-ku, Kobe 654-0037 (Japan); National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564 (Japan)

2007-07-15T23:59:59.000Z

35

Structural and composition investigations at delayered locations of low k integrated circuit device by gas-assisted focused ion beam  

SciTech Connect (OSTI)

The authors report a new delayering technique – gas-assisted focused ion beam (FIB) method and its effects on the top layer materials of integrated circuit (IC) device. It demonstrates a highly efficient failure analysis with investigations on the precise location. After removing the dielectric layers under the bombardment of an ion beam, the chemical composition of the top layer was altered with the reduced oxygen content. Further energy-dispersive x-ray spectroscopy and Fourier transform infrared analysis revealed that the oxygen reduction lead to appreciable silicon suboxide formation. Our findings with structural and composition alteration of dielectric layer after FIB delayering open up a new insight avenue for the failure analysis in IC devices.

Wang, Dandan, E-mail: dandan.wang@globalfoundries.com; Kee Tan, Pik; Yamin Huang, Maggie; Lam, Jeffrey; Mai, Zhihong [Technology Development Department, GLOBALFOUNDRIES Singapore Pte. Ltd., 60 Woodlands Industrial Park D, Street 2, Singapore 738406 (Singapore)

2014-05-15T23:59:59.000Z

36

Three-Dimensional Reconstruction and Microstructure Modeling of Porosity-Graded Cathode Using Focused Ion Beam and Homogenization Techniques  

SciTech Connect (OSTI)

In this study, microstructure of a porosity-graded lanthanum strontium manganite (LSM) cathode of solid oxide fuel cells (SOFCs) has been characterized using focused ion beam (FIB) and scanning electron microscopy(SEM) combined with image processing. Two-point correlation functions of the two-dimensional (2D) images taken along the direction of porosity gradient are used to reconstruct a three-dimensional (3D) microstructure. The effective elastic modulus of the two-phase porosity-graded cathode is predicted using strong contrast (SC) and composite inclusion (CI) homogenization techniques. The effectiveness of the two methods in predicting the effective elastic properties of the porositygraded LSM cathode is investigated in comparison with the results obtained from the finite element model (FEM).

Hamedani, Amani; Baniassadi, Majid; Sheidaei, A.; Pourboghrat, F.; Remond, Y.; Khaleel, Mohammad A.; Garmestani, Hamid

2014-02-28T23:59:59.000Z

37

Comparison of SOFC Cathode Microstructure Quantified using X-ray Nanotomography and Focused Ion Beam - Scanning Electron Microscopy  

SciTech Connect (OSTI)

X-ray nanotomography and focused ion beam scanning electron microscopy (FIB?SEM) have been applied to investigate the complex 3D microstructure of solid oxide fuel cell (SOFC) electrodes at spatial resolutions of 45 nm and below. The application of near edge differential absorption for x-ray nanotomography and energy selected backscatter detection for FIB–SEM enable elemental mapping within the microstructure. Using these methods, non?destructive 3D x-ray imaging and FIB–SEM serial sectioning have been applied to compare three?dimensional elemental mapping of the LSM, YSZ, and pore phases in the SOFC cathode microstructure. The microstructural characterization of an SOFC cathode is reported based on these measurements. The results presented demonstrate the viability of x-ray nanotomography as a quantitative characterization technique and provide key insights into the SOFC cathode microstructure.

Nelson, George J.; Harris, William H.; Lombardo, Jeffrey J.; Izzo, Jr., John R.; Chiu, W. K. S.; Tanasini, Pietro; cantoni, Marco; Van herle, Jan; Comninellis, Christos; Andrews, Joy C.; Liu, Yijin; Pianetta, Piero; Chu, Yong

2011-01-01T23:59:59.000Z

38

Ultramicroscopy 103 (2005) 6781 Conventional and back-side focused ion beam milling  

E-Print Network [OSTI]

prepared using the more conventional `trench' FIB geometry. The use of carbon coating to remove specimen is used, then the local intensity and spacing of the interference fringes that form in the overlap region as it provides direct access to the electrostatic potential in the specimen (projected in the electron beam

Dunin-Borkowski, Rafal E.

39

Long Plasma Source for Heavy Ion Beam Charge Neutralization  

E-Print Network [OSTI]

neutralizing plasma column the heavy ion beam can focus to aPlasmas are a source of unbound electrons for charge neutralizing intense heavy ion beams to focus

Efthimion, P.C.

2009-01-01T23:59:59.000Z

40

Surface plasmon polariton modes in a single-crystal Au nanoresonator fabricated using focused-ion-beam milling  

E-Print Network [OSTI]

to 30 keV, and focused by an electrostatic lens system to a spot size with diameter as small as 5­10 nm, photovoltaics, tele- communications, and optoelectronic circuit integration due to their ability to concentrate.5,6 In a typical FIB system, Ga+ ions are extracted from a liquid-metal ion source, accel- erated

Polman, Albert

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Broad beam ion implanter  

DOE Patents [OSTI]

An ion implantation device for creating a large diameter, homogeneous, ion beam is described, as well as a method for creating same, wherein the device is characterized by extraction of a diverging ion beam and its conversion by ion beam optics to an essentially parallel ion beam. The device comprises a plasma or ion source, an anode and exit aperture, an extraction electrode, a divergence-limiting electrode and an acceleration electrode, as well as the means for connecting a voltage supply to the electrodes.

Leung, Ka-Ngo (Hercules, CA)

1996-01-01T23:59:59.000Z

42

Finding beam focus errors automatically  

SciTech Connect (OSTI)

An automated method for finding beam focus errors using an optimization program called COMFORT-PLUS. The steps involved in finding the correction factors using COMFORT-PLUS has been used to find the beam focus errors for two damping rings at the SLAC Linear Collider. The program is to be used as an off-line program to analyze actual measured data for any SLC system. A limitation on the application of this procedure is found to be that it depends on the magnitude of the machine errors. Another is that the program is not totally automated since the user must decide a priori where to look for errors. (LEW)

Lee, M.J.; Clearwater, S.H.; Kleban, S.D.

1987-01-01T23:59:59.000Z

43

Pulsed ion beam source  

DOE Patents [OSTI]

An improved pulsed ion beam source having a new biasing circuit for the fast magnetic field. This circuit provides for an initial negative bias for the field created by the fast coils in the ion beam source which pre-ionize the gas in the source, ionize the gas and deliver the gas to the proper position in the accelerating gap between the anode and cathode assemblies in the ion beam source. The initial negative bias improves the interaction between the location of the nulls in the composite magnetic field in the ion beam source and the position of the gas for pre-ionization and ionization into the plasma as well as final positioning of the plasma in the accelerating gap. Improvements to the construction of the flux excluders in the anode assembly are also accomplished by fabricating them as layered structures with a high melting point, low conductivity material on the outsides with a high conductivity material in the center.

Greenly, John B. (Lansing, NY)

1997-01-01T23:59:59.000Z

44

Ion-beam technologies  

SciTech Connect (OSTI)

This compilation of figures and diagrams reviews processes for depositing diamond/diamond-like carbon films. Processes addressed are chemical vapor deposition (HFCVD, PACVD, etc.), plasma vapor deposition (plasma sputtering, ion beam sputtering, evaporation, etc.), low-energy ion implantation, and hybrid processes (biased sputtering, IBAD, biased HFCVD, etc.). The tribological performance of coatings produced by different means is discussed.

Fenske, G.R. [Argonne National Lab., IL (United States)

1993-01-01T23:59:59.000Z

45

Robust Collimation Control of Laser-Generated Ion Beam  

E-Print Network [OSTI]

The robustness of a structured collimation device is discussed for an intense-laser-produced ion beam. In this paper the ion beam collimation is realized by the solid structured collimation device, which produces the transverse electric field; the electric field contributes to reduce the ion beam transverse velocity and collimate the ion beam. Our 2.5 dimensional particle-in cell simulations demonstrate that the collimation device is rather robust against the changes in the laser parameters and the collimation target sizes. The intense short-pulse lasers are now available, and are used to generate an ion beam. The issues in the laser ion acceleration include an ion beam collimation, ion energy spectrum control, ion production efficiency, ion energy control, ion beam bunching, etc. The laser-produced ion beam tends to expand in the transverse and longitudinal directions during the ion beam propagation. The ion beam collimation is focused in this paper.

Kawata, S; Kamiyama, D; Nagashima, T; Barada, D; Gu, Y J; Li, X; Yu, Q; Kong, Q; Wang, P X

2015-01-01T23:59:59.000Z

46

Chemical Imaging Analysis of Environmental Particles Using the Focused Ion Beam/Scanning Electron Microscopy Technique: Microanalysis Insights into Atmospheric Chemistry of Fly Ash  

SciTech Connect (OSTI)

Airborne fly ash from coal combustion may represent a source of bioavailable iron (Fe) in the open ocean. However, few studies have been made focusing on Fe speciation and distribution in coal fly ash. In this study, chemical imaging of fly ash has been performed using a dual-beam FIB/SEM (focused ion beam/scanning electron microscope) system for a better understanding of how simulated atmospheric processing modify the morphology, chemical compositions and element distributions of individual particles. A novel approach has been applied for cross-sectioning of fly ash specimen with a FIB in order to explore element distribution within the interior of individual particles. Our results indicate that simulated atmospheric processing causes disintegration of aluminosilicate glass, a dominant material in fly ash particles. Aluminosilicate-phase Fe in the inner core of fly ash particles is more easily mobilized compared with oxide-phase Fe present as surface aggregates on fly ash spheres. Fe release behavior depends strongly on Fe speciation in aerosol particles. The approach for preparation of cross-sectioned specimen described here opens new opportunities for particle microanalysis, particular with respect to inorganic refractive materials like fly ash and mineral dust.

Chen, Haihan; Grassian, Vicki H.; Saraf, Laxmikant V.; Laskin, Alexander

2013-01-21T23:59:59.000Z

47

Pulsed ion beam source  

DOE Patents [OSTI]

An improved pulsed ion beam source is disclosed having a new biasing circuit for the fast magnetic field. This circuit provides for an initial negative bias for the field created by the fast coils in the ion beam source which pre-ionize the gas in the source, ionize the gas and deliver the gas to the proper position in the accelerating gap between the anode and cathode assemblies in the ion beam source. The initial negative bias improves the interaction between the location of the nulls in the composite magnetic field in the ion beam source and the position of the gas for pre-ionization and ionization into the plasma as well as final positioning of the plasma in the accelerating gap. Improvements to the construction of the flux excluders in the anode assembly are also accomplished by fabricating them as layered structures with a high melting point, low conductivity material on the outsides with a high conductivity material in the center. 12 figs.

Greenly, J.B.

1997-08-12T23:59:59.000Z

48

Beams 92: Proceedings. Volume 2, Ion beams, electron beams, diagnostics  

SciTech Connect (OSTI)

This report contains papers on the following topics. Ion beam papers; electron beam papers; and these papers have been indexed separately elsewhere.

Mosher, D.; Cooperstein, G. [eds.] [Naval Research Lab., Washington, DC (United States)] [eds.; Naval Research Lab., Washington, DC (United States)

1993-12-31T23:59:59.000Z

49

Electrostatic plasma lens for focusing negatively charged particle beams  

SciTech Connect (OSTI)

We describe the current status of ongoing research and development of the electrostatic plasma lens for focusing and manipulating intense negatively charged particle beams, electrons, and negative ions. The physical principle of this kind of plasma lens is based on magnetic isolation electrons providing creation of a dynamical positive space charge cloud in shortly restricted volume propagating beam. Here, the new results of experimental investigations and computer simulations of wide-aperture, intense electron beam focusing by plasma lens with positive space charge cloud produced due to the cylindrical anode layer accelerator creating a positive ion stream towards an axis system is presented.

Goncharov, A. A.; Dobrovolskiy, A. M.; Dunets, S. M. [Institute of Physics NAS of Ukraine, Kiev 03028, Ave. Nauki 46 (Ukraine); Litovko, I. V. [Institute for Nuclear Research NAS of Ukraine, Kiev 03650, pr. Nauki 47 (Ukraine); Gushenets, V. I.; Oks, E. M. [High-Current Electronics Institute SB of RAS, Tomsk (Russian Federation)

2012-02-15T23:59:59.000Z

50

Plasma ion sources and ion beam technology inmicrofabrications  

SciTech Connect (OSTI)

For over decades, focused ion beam (FIB) has been playing a very important role in microscale technology and research, among which, semiconductor microfabrication is one of its biggest application area. As the dimensions of IC devices are scaled down, it has shown the need for new ion beam tools and new approaches to the fabrication of small-scale devices. In the meanwhile, nanotechnology has also deeply involved in material science research and bioresearch in recent years. The conventional FIB systems which utilize liquid gallium ion sources to achieve nanometer scale resolution can no longer meet the various requirements raised from such a wide application area such as low contamination, high throughput and so on. The drive towards controlling materials properties at nanometer length scales relies on the availability of efficient tools. In this thesis, three novel ion beam tools have been developed and investigated as the alternatives for the conventional FIB systems in some particular applications. An integrated focused ion beam (FIB) and scanning electron microscope (SEM) system has been developed for direct doping or surface modification. This new instrument employs a mini-RF driven plasma source to generate focused ion beam with various ion species, a FEI two-lens electron (2LE) column for SEM imaging, and a five-axis manipulator system for sample positioning. An all-electrostatic two-lens column has been designed to focus the ion beam extracted from the source. Based on the Munro ion optics simulation, beam spot sizes as small as 100 nm can be achieved at beam energies between 5 to 35 keV if a 5 {micro}m-diameter extraction aperture is used. Smaller beam spot sizes can be obtained with smaller apertures at sacrifice of some beam current. The FEI 2LE column, which utilizes Schottky emission, electrostatic focusing optics, and stacked-disk column construction, can provide high-resolution (as small as 20 nm) imaging capability, with fairly long working distance (25 mm) at 25 keV beam voltage. Such an integrated FIB/SEM dual-beam system will not only improve the accuracy and reproducibility when performing ion beam sculpting and direct implantation processes, but will also enable researchers to perform cross-sectioning, imaging, and analysis with the same tool. A major advantage of this approach is the ability to produce a wide variety of ion species tailored to the application.

Ji, Lili

2007-09-01T23:59:59.000Z

51

ECR plasma source for heavy ion beam charge neutralization  

E-Print Network [OSTI]

plasmas are being considered as a medium for charge neutralizing heavy ion beams in order to focus beyond resonance. Keywords: Plasma focus; RF plasma; Beam charge neutralization 1. INTRODUCTION A possible heavyECR plasma source for heavy ion beam charge neutralization PHILIP C. EFTHIMION,1 ERIK GILSON,1

Gilson, Erik

52

Ion beam processing of advanced electronic materials  

SciTech Connect (OSTI)

This report contains research programs discussed at the materials research society symposia on ion beam processing of advanced electronic materials. Major topics include: shallow implantation and solid-phase epitaxy; damage effects; focused ion beams; MeV implantation; high-dose implantation; implantation in III-V materials and multilayers; and implantation in electronic materials. Individual projects are processed separately for the data bases. (CBS)

Cheung, N.W.; Marwick, A.D.; Roberto, J.B. (eds.) (California Univ., Berkeley, CA (USA); International Business Machines Corp., Yorktown Heights, NY (USA). Thomas J. Watson Research Center; Oak Ridge National Lab., TN (USA))

1989-01-01T23:59:59.000Z

53

Laser acceleration of ion beams  

E-Print Network [OSTI]

We consider methods of charged particle acceleration by means of high-intensity lasers. As an application we discuss a laser booster for heavy ion beams provided, e.g. by the Dubna nuclotron. Simple estimates show that a cascade of crossed laser beams would be necessary to provide additional acceleration to gold ions of the order of GeV/nucleon.

I. A. Egorova; A. V. Filatov; A. V. Prozorkevich; S. A. Smolyansky; D. B. Blaschke; M. Chubaryan

2007-02-01T23:59:59.000Z

54

Nanostructure fabrication by electron and ion beam patterning of nanoparticles  

E-Print Network [OSTI]

Two modes of energetic beam-mediated fabrication have been investigated, namely focused ion beam (FIB) direct-writing of nanoparticles, and a technique for electrostatically patterning ionized inorganic nanoparticles, ...

Kong, David Sun, 1979-

2004-01-01T23:59:59.000Z

55

Ion beam requirements for fast ignition of inertial fusion targets  

E-Print Network [OSTI]

Ion beam requirements for fast ignition are investigated by numerical simulation taking into account new effects such as ion beam divergence not included before. We assume that ions are generated by the TNSA scheme in a curved foil placed inside a re-entrant cone and focused on the cone apex or beyond. From the focusing point to the compressed core ions propagate with a given divergence angle. Ignition energies are obtained for two compressed fuel configurations heated by proton and carbon ion beams. The dependence of the ignition energies on the beam divergence angle and on the position of the ion beam focusing point have been analysed. Comparison between TNSA and quasi-monoenergetic ions is also shown.

Honrubia, J J

2015-01-01T23:59:59.000Z

56

Classical trajectory Monte Carlo code for simulating ion beam focusing or defocusing with magnetic elements modeled as current loops or current lines  

SciTech Connect (OSTI)

A computational tool is described that can be used for designing magnetic focusing or defocusing systems. A fully three-dimensional classical trajectory Monte Carlo simulation has been developed. Ion trajectories are simulated in the presence of magnetic elements that can be modeled as any combination of current loops and current lines. Each current loop or line may be located anywhere in the system and oriented along any of the three coordinate axes. The configuration need not be axisymmetric. The solutions are obtained using normalized parameters, which can be used for easily scaling the results. Examples are provided of the utility of the code.

Lane, R. A.; Ordonez, C. A. [Department of Physics, University of North Texas, Denton, Texas (United States)

2013-04-19T23:59:59.000Z

57

FOCUSED GAUSSIAN BEAMS FOR SEISMIC IMAGING ROBERT L. NOWACK  

E-Print Network [OSTI]

FOCUSED GAUSSIAN BEAMS FOR SEISMIC IMAGING ROBERT L. NOWACK Abstract. The application of focused Gaussian beams is investigated for the seismic imaging of common-shot reflection data. The focusing of Gaussian beams away from the source and receiver surface adds flexibility to beam imaging algorithms

Nowack, Robert L.

58

Ion-beam-driven electrostatic ion cyclotron instabilities  

SciTech Connect (OSTI)

We present results of numerical simulations on the electrostatic ion cyclotron instabilities driven by the ion beam parallel to the magnetic field. For the beam speed exceeding the thermal speed of background ions and the beam temperature much lower than the background ion temperature, it is found that the instability results in strong perpendicular heating and slowing down of parallel drift of the beam ions, leading to the saturation of the instability. Applications to plasma heating and space plasma physics are discussed.

Miura, A.; Okuda, H.; Ashour-Abdalla, M.

1982-10-01T23:59:59.000Z

59

Ion beam extractor with counterbore  

DOE Patents [OSTI]

An extractor system for a plasma ion source has a single (first) electrode with one or more apertures, or a pair of spaced electrodes, a first or plasma forming electrode and a second or extraction electrode, with one or more aligned apertures. The aperture(s) in the first electrode (or the second electrode or both) have a counterbore on the downstream side (i.e. away from the plasma ion source or facing the second electrode). The counterbored extraction system reduces aberrations and improves focusing. The invention also includes an ion source with the counterbored extraction system, and a method of improving focusing in an extraction system by providing a counterbore.

Ji, Qing; Standiford, Keith; King, Tsu-Jae; Leung, Ka-Ngo

2006-08-01T23:59:59.000Z

60

PIC MODELING: Measuring Ion Beam Current Density in the  

E-Print Network [OSTI]

-Mission Research, Albuquerque, NM 87110 #12;2Ion beams focused beyond the space-charge limit via plasma pressure chamber Final focus magnet Target RF Source: Volume plasma (from photoionization of hot target W m-2 With plasma: Without plasma: Also, can't transversely focus without plasma! #12;7LSP predicts

Kaganovich, Igor

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Oxygen ion-beam microlithography  

DOE Patents [OSTI]

A method of providing and developing a resist on a substrate for constructing integrated circuit (IC) chips includes the following steps: of depositing a thin film of amorphous silicon or hydrogenated amorphous silicon on the substrate and exposing portions of the amorphous silicon to low-energy oxygen ion beams to oxidize the amorphous silicon at those selected portions. The nonoxidized portions are then removed by etching with RF-excited hydrogen plasma. Components of the IC chip can then be constructed through the removed portions of the resist. The entire process can be performed in an in-line vacuum production system having several vacuum chambers. Nitrogen or carbon ion beams can also be used.

Tsuo, Y. Simon (Lakewood, CO)

1991-01-01T23:59:59.000Z

62

H-Mode Accelerating Structures with PMQ Beam Focusing  

E-Print Network [OSTI]

We have developed high-efficiency normal-conducting RF accelerating structures by combining H-mode resonator cavities and a transverse beam focusing by permanent-magnet quadrupoles (PMQ), for beam velocities in the range of a few percent of the speed of light. The shunt impedance of inter-digital H-mode (IH-PMQ) structures is 10-20 times higher than that of a conventional drift-tube linac, while the transverse size is 4-5 times smaller. Results of the combined 3-D modeling - electromagnetic computations, multi-particle beam-dynamics simulations with high currents, and thermal-stress analysis - for an IH-PMQ accelerator tank are presented. The accelerating field profile in the tank is tuned to provide the best propagation of a 50-mA deuteron beam using coupled iterations of electromagnetic and beam-dynamics modeling. Measurements of a cold model of the IH-PMQ tank show a good agreement with the calculations. H-PMQ accelerating structures following a short RFQ can be used both in the front end of ion linacs or ...

Kurennoy, Sergey S; O'Hara, James F; Olivas, Eric R; Wangler, Thomas P

2011-01-01T23:59:59.000Z

63

Are Cluster Ion Analysis Beams Good Choices for Hydrogen Depth...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Cluster Ion Analysis Beams Good Choices for Hydrogen Depth Profiling Using Time-of-Flight Secondary Ion Mass Spectrometry? Are Cluster Ion Analysis Beams Good Choices for Hydrogen...

64

Thermal equilibrium theory of periodically focused charged-particle beams  

E-Print Network [OSTI]

A thermal equilibrium theory of periodically focused charged-particle beams is presented in the framework of both warm-fluid and kinetic descriptions. In particular, the thermal beam equilibria are discussed for paraxial ...

Samokhvalova, Ksenia R

2008-01-01T23:59:59.000Z

65

The Electron Beam Ion Source (EBIS)  

ScienceCinema (OSTI)

Brookhaven National Lab has successfully developed a new pre-injector system, called the Electron Beam Ion Source, for the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory science programs. The first of several planned improvemen

Brookhaven Lab

2010-01-08T23:59:59.000Z

66

Josephson Junctions and Devices fabricated by Focused Electron Beam Irradiation  

E-Print Network [OSTI]

Josephson Junctions and Devices fabricated by Focused Electron Beam Irradiation Wilfred Edwin Booij Gonville and Caius College Cambridge A dissertation submitted for the degree of Doctor of Philosophy at the University of Cambridge December 1997... Summary Josephson Junctions and Devices fabricated by Focused Electron Beam Irradiation The irradiation of high Tc superconducting thin films with a focused electron beam, such as that obtained in a scanning transmission electron microscope (STEM), can...

Booij, Wilfred Edwin

67

Intense Ion Beam for Warm Dense Matter Physics  

SciTech Connect (OSTI)

The Neutralized Drift Compression Experiment (NDCX) at Lawrence Berkeley National Laboratory is exploring the physical limits of compression and focusing of ion beams for heating material to warm dense matter (WDM) and fusion ignition conditions. The NDCX is a beam transport experiment with several components at a scale comparable to an inertial fusion energy driver. The NDCX is an accelerator which consists of a low-emittance ion source, high-current injector, solenoid matching section, induction bunching module, beam neutralization section, and final focusing system. The principal objectives of the experiment are to control the beam envelope, demonstrate effective neutralization of the beam space-charge, control the velocity tilt on the beam, and understand defocusing effects, field imperfections, and limitations on peak intensity such as emittance and aberrations. Target heating experiments with space-charge dominated ion beams require simultaneous longitudinal bunching and transverse focusing. A four-solenoid lattice is used to tune the beam envelope to the necessary focusing conditions before entering the induction bunching module. The induction bunching module provides a head-to-tail velocity ramp necessary to achieve peak axial compression at the desired focal plane. Downstream of the induction gap a plasma column neutralizes the beam space charge so only emittance limits the focused beam intensity. We present results of beam transport through a solenoid matching section and simultaneous focusing of a singly charged K{sup +} ion bunch at an ion energy of 0.3 MeV. The results include a qualitative comparison of experimental and calculated results after the solenoid matching section, which include time resolved current density, transverse distributions, and phase-space of the beam at different diagnostic planes. Electron cloud and gas measurements in the solenoid lattice and in the vicinity of intercepting diagnostics are also presented. Finally, comparisons of improved experimental and calculated axial focus (> 100 x axial compression, < 2 ns pulses) and higher peak energy deposition on target are also presented. These achievements demonstrate the capabilities for near term target heating experiments to T{sub e} {approx} 0.1 eV and for future ion accelerators to heat targets to T{sub e} > 1 eV.

Coleman, Joshua Eugene

2008-05-23T23:59:59.000Z

68

Measurements and simulations of focused beam for orthovoltage therapy  

SciTech Connect (OSTI)

Purpose: Megavoltage photon beams are typically used for therapy because of their skin-sparing effect. However, a focused low-energy x-ray beam would also be skin sparing, and would have a higher dose concentration at the focal spot. Such a beam can be produced with polycapillary optics. MCNP5 was used to model dose profiles for a scanned focused beam, using measured beam parameters. The potential of low energy focused x-ray beams for radiation therapy was assessed. Methods: A polycapillary optic was used to focus the x-ray beam from a tungsten source. The optic was characterized and measurements were performed at 50 kV. PMMA blocks of varying thicknesses were placed between optic and the focal spot to observe any variation in the focusing of the beam after passing through the tissue-equivalent material. The measured energy spectrum was used to model the focused beam in MCNP5. A source card (SDEF) in MCNP5 was used to simulate the converging x-ray beam. Dose calculations were performed inside a breast tissue phantom. Results: The measured focal spot size for the polycapillary optic was 0.2 mm with a depth of field of 5 mm. The measured focal spot remained unchanged through 40 mm of phantom thickness. The calculated depth dose curve inside the breast tissue showed a dose peak several centimeters below the skin with a sharp dose fall off around the focus. The percent dose falls below 10% within 5 mm of the focus. It was shown that rotating the optic during scanning would preserve the skin-sparing effect of the focused beam. Conclusions: Low energy focused x-ray beams could be used to irradiate tumors inside soft tissue within 5 cm of the surface.

Abbas, Hassan, E-mail: Hassan.Abbas@Yale.Edu [Department of Therapeutic Radiology, Yale University School of Medicine, Yale-New Haven Hospital, New Haven, 344 Lane Street Hamden, Connecticut 06514 (United States)] [Department of Therapeutic Radiology, Yale University School of Medicine, Yale-New Haven Hospital, New Haven, 344 Lane Street Hamden, Connecticut 06514 (United States); Mahato, Dip N., E-mail: dip.n.mahato@intel.com [Intel Corporation, Mail-Stop RA3-410, 2501 NW 229th Avenue, Hillsboro, Oregon 97124 (United States); Satti, Jahangir, E-mail: sattij@mail.amc.edu [Department of Radiation Oncology, Albany Medical Center, 43 New Scotland Avenue, Albany, New York 12208 (United States)] [Department of Radiation Oncology, Albany Medical Center, 43 New Scotland Avenue, Albany, New York 12208 (United States); MacDonald, C. A., E-mail: c.macdonald@albany.edu [Department of Physics, University at Albany, SUNY, 1400 Washington Avenue, Albany, New York 12222 (United States)

2014-04-15T23:59:59.000Z

69

Physics of neutralization of intense high-energy ion beam pulses by electronsa...  

E-Print Network [OSTI]

Physics of neutralization of intense high-energy ion beam pulses by electronsa... I. D. Kaganovich beams,13 the physics of solar flares,14 high-intensity high- energy particle beam propagation Neutralization and focusing of intense charged particle beam pulses by electrons form the basis for a wide range

Kaganovich, Igor

70

Flow-through ion beam source  

DOE Patents [OSTI]

A method and an apparatus for forming a charge neutral ion beam which is useful in producing thin films of material on electrically conductive or non-conductive substrates are provided. 4 figs.

Springer, R.W.

1997-02-11T23:59:59.000Z

71

Irradiation of Dye-Doped Microspheres with a Strongly Focused Laser Beam  

E-Print Network [OSTI]

Irradiation of Dye-Doped Microspheres with a Strongly Focused Laser Beam Results in Alignment upon Optical Trapping Garth J. Simpson, Thorsten Wohland, and Richard N. Zare* Department of Chemistry Received December 12, 2001 ABSTRACT The irradiation of dye-doped polystyrene microspheres with an argon ion

Zare, Richard N.

72

A pencil beam algorithm for helium ion beam therapy  

SciTech Connect (OSTI)

Purpose: To develop a flexible pencil beam algorithm for helium ion beam therapy. Dose distributions were calculated using the newly developed pencil beam algorithm and validated using Monte Carlo (MC) methods. Methods: The algorithm was based on the established theory of fluence weighted elemental pencil beam (PB) kernels. Using a new real-time splitting approach, a minimization routine selects the optimal shape for each sub-beam. Dose depositions along the beam path were determined using a look-up table (LUT). Data for LUT generation were derived from MC simulations in water using GATE 6.1. For materials other than water, dose depositions were calculated by the algorithm using water-equivalent depth scaling. Lateral beam spreading caused by multiple scattering has been accounted for by implementing a non-local scattering formula developed by Gottschalk. A new nuclear correction was modelled using a Voigt function and implemented by a LUT approach. Validation simulations have been performed using a phantom filled with homogeneous materials or heterogeneous slabs of up to 3 cm. The beams were incident perpendicular to the phantoms surface with initial particle energies ranging from 50 to 250 MeV/A with a total number of 10{sup 7} ions per beam. For comparison a special evaluation software was developed calculating the gamma indices for dose distributions. Results: In homogeneous phantoms, maximum range deviations between PB and MC of less than 1.1% and differences in the width of the distal energy falloff of the Bragg-Peak from 80% to 20% of less than 0.1 mm were found. Heterogeneous phantoms using layered slabs satisfied a {gamma}-index criterion of 2%/2mm of the local value except for some single voxels. For more complex phantoms using laterally arranged bone-air slabs, the {gamma}-index criterion was exceeded in some areas giving a maximum {gamma}-index of 1.75 and 4.9% of the voxels showed {gamma}-index values larger than one. The calculation precision of the presented algorithm was considered to be sufficient for clinical practice. Although only data for helium beams was presented, the performance of the pencil beam algorithm for proton beams was comparable. Conclusions: The pencil beam algorithm developed for helium ions presents a suitable tool for dose calculations. Its calculation speed was evaluated to be similar to other published pencil beam algorithms. The flexible design allows easy customization of measured depth-dose distributions and use of varying beam profiles, thus making it a promising candidate for integration into future treatment planning systems. Current work in progress deals with RBE effects of helium ions to complete the model.

Fuchs, Hermann; Stroebele, Julia; Schreiner, Thomas; Hirtl, Albert; Georg, Dietmar [Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, 1090 Vienna (Austria); Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria) and Comprehensive Cancer Center, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria); Department of Radiation Oncology, Medical University of Vienna/AKH Vienna (Austria) and Comprehensive Cancer Center, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria); PEG MedAustron, 2700 Wiener Neustadt (Austria); Department of Nuclear Medicine, Medical University of Vienna, 1090 Vienna (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, 1090 Vienna (Austria); Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria) and Comprehensive Cancer Center, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria)

2012-11-15T23:59:59.000Z

73

Beam current controller for laser ion source  

DOE Patents [OSTI]

The present invention relates to the design and use of an ion source with a rapid beam current controller for experimental and medicinal purposes. More particularly, the present invention relates to the design and use of a laser ion source with a magnetic field applied to confine a plasma flux caused by laser ablation.

Okamura, Masahiro

2014-10-28T23:59:59.000Z

74

The role of space charge compensation for ion beam extraction and ion beam transport (invited)  

SciTech Connect (OSTI)

Depending on the specific type of ion source, the ion beam is extracted either from an electrode surface or from a plasma. There is always an interface between the (almost) space charge compensated ion source plasma, and the extraction region in which the full space charge is influencing the ion beam itself. After extraction, the ion beam is to be transported towards an accelerating structure in most cases. For lower intensities, this transport can be done without space charge compensation. However, if space charge is not negligible, the positive charge of the ion beam will attract electrons, which will compensate the space charge, at least partially. The final degree of Space Charge Compensation (SCC) will depend on different properties, like the ratio of generation rate of secondary particles and their loss rate, or the fact whether the ion beam is pulsed or continuous. In sections of the beam line, where the ion beam is drifting, a pure electrostatic plasma will develop, whereas in magnetic elements, these space charge compensating electrons become magnetized. The transport section will provide a series of different plasma conditions with different properties. Different measurement tools to investigate the degree of space charge compensation will be described, as well as computational methods for the simulation of ion beams with partial space charge compensation.

Spädtke, Peter, E-mail: p.spaedtke@gsi.de [GSI Helmholtzzentrum für Schwerionenforschung GmbH (Germany)] [GSI Helmholtzzentrum für Schwerionenforschung GmbH (Germany)

2014-02-15T23:59:59.000Z

75

Cleaning Membranes with Focused Ultrasound Beams for Drinking Water Treatment  

E-Print Network [OSTI]

Cleaning Membranes with Focused Ultrasound Beams for Drinking Water Treatment Jian-yu Lu1 , Xi Du2: jilu@eng.utoledo.edu Abstract ­ Traditional methods for water treatment are not effective to remove to clean a large membrane area needed for a typical water treatment plant. In this paper, a focused

Lu, Jian-yu

76

Aerosol beam-focus laser-induced plasma spectrometer device  

DOE Patents [OSTI]

An apparatus for detecting elements in an aerosol includes an aerosol beam focuser for concentrating aerosol into an aerosol beam; a laser for directing a laser beam into the aerosol beam to form a plasma; a detection device that detects a wavelength of a light emission caused by the formation of the plasma. The detection device can be a spectrometer having at least one grating and a gated intensified charge-coupled device. The apparatus may also include a processor that correlates the wavelength of the light emission caused by the formation of the plasma with an identity of an element that corresponds to the wavelength. Furthermore, the apparatus can also include an aerosol generator for forming an aerosol beam from bulk materials. A method for detecting elements in an aerosol is also disclosed.

Cheng, Meng-Dawn (Oak Ridge, TN)

2002-01-01T23:59:59.000Z

77

Microchip and wedge ion funnels and planar ion beam analyzers using same  

DOE Patents [OSTI]

Electrodynamic ion funnels confine, guide, or focus ions in gases using the Dehmelt potential of oscillatory electric field. New funnel designs operating at or close to atmospheric gas pressure are described. Effective ion focusing at such pressures is enabled by fields of extreme amplitude and frequency, allowed in microscopic gaps that have much higher electrical breakdown thresholds in any gas than the macroscopic gaps of present funnels. The new microscopic-gap funnels are useful for interfacing atmospheric-pressure ionization sources to mass spectrometry (MS) and ion mobility separation (IMS) stages including differential IMS or FAIMS, as well as IMS and MS stages in various configurations. In particular, "wedge" funnels comprising two planar surfaces positioned at an angle and wedge funnel traps derived therefrom can compress ion beams in one dimension, producing narrow belt-shaped beams and laterally elongated cuboid packets. This beam profile reduces the ion density and thus space-charge effects, mitigating the adverse impact thereof on the resolving power, measurement accuracy, and dynamic range of MS and IMS analyzers, while a greater overlap with coplanar light or particle beams can benefit spectroscopic methods.

Shvartsburg, Alexandre A; Anderson, Gordon A; Smith, Richard D

2012-10-30T23:59:59.000Z

78

High-powered pulsed-ion-beam acceleration and transport  

SciTech Connect (OSTI)

The state of research on intense ion beam acceleration and transport is reviewed. The limitations imposed on ion beam transport by space charge effects and methods available for neutralization are summarized. The general problem of ion beam neutralization in regions free of applied electric fields is treated. The physics of acceleration gaps is described. Finally, experiments on multi-stage ion acceleration are summarized.

Humphries, S. Jr.; Lockner, T.R.

1981-11-01T23:59:59.000Z

79

Using neutral beams as a light ion beam probe (invited)  

SciTech Connect (OSTI)

By arranging the particle first banana orbits to pass near a distant detector, the light ion beam probe (LIBP) utilizes orbital deflection to probe internal fields and field fluctuations. The LIBP technique takes advantage of (1) the in situ, known source of fast ions created by beam-injected neutral particles that naturally ionize near the plasma edge and (2) various commonly available diagnostics as its detector. These born trapped particles can traverse the plasma core on their inner banana leg before returning to the plasma edge. Orbital displacements (the forces on fast ions) caused by internal instabilities or edge perturbing fields appear as modulated signal at an edge detector. Adjustments in the q-profile and plasma shape that determine the first orbit, as well as the relative position of the source and detector, enable studies under a wide variety of plasma conditions. This diagnostic technique can be used to probe the impact on fast ions of various instabilities, e.g., Alfvén eigenmodes (AEs) and neoclassical tearing modes, and of externally imposed 3D fields, e.g., magnetic perturbations. To date, displacements by AEs and by externally applied resonant magnetic perturbation fields have been measured using a fast ion loss detector. Comparisons with simulations are shown. In addition, nonlinear interactions between fast ions and independent AE waves are revealed by this technique.

Chen, Xi, E-mail: chenxi@fusion.gat.com [Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37831 (United States); Heidbrink, W. W. [University of California Irvine, Irvine, California 92697 (United States); Van Zeeland, M. A.; Pace, D. C.; Petty, C. C.; Fisher, R. K. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Kramer, G. J.; Nazikian, R. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States); Austin, M. E. [University of Texas at Austin, Austin, Texas 78712 (United States); Hanson, J. M. [Columbia University, New York, New York 10027 (United States); Zeng, L. [University of California Los Angeles, Los Angeles, California 90095 (United States)

2014-11-15T23:59:59.000Z

80

Ion beam assisted deposition of thermal barrier coatings  

DOE Patents [OSTI]

Methods and apparatus for depositing thermal barrier coatings on gas turbine blades and vanes using Electron Beam Physical Vapor Deposition (EBPVD) combined with Ion Beam Assisted Deposition (IBAD).

Youchison, Dennis L. (Albuquerque, NM); McDonald, Jimmie M. (Albuquerque, NM); Lutz, Thomas J. (Albuquerque, NM); Gallis, Michail A. (Albuquerque, NM)

2010-11-23T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Reflection of focused beams from opal photonic crystals  

E-Print Network [OSTI]

. Chutinan, "Full Three-Dimensional Photonic Bandgap Crystals at Near-Infrared Wavelengths," Science 289, 604Reflection of focused beams from opal photonic crystals Karri Varis, Marco Mattila Optoelectronics 10-14, D-55099 Mainz, Germany Abstract: We present a robust method for computing the reflection

Jonsson, Fredrik

82

Electrostatic quadrupole focused particle accelerating assembly with laminar flow beam  

DOE Patents [OSTI]

A charged particle accelerating assembly provided with a predetermined ratio of parametric structural characteristics and with related operating voltages applied to each of its linearly spaced focusing and accelerating quadrupoles, thereby to maintain a particle beam traversing the electrostatic fields of the quadrupoles in the assembly in an essentially laminar flow through the assembly.

Maschke, A.W.

1984-04-16T23:59:59.000Z

83

Physics with fast molecular-ion beams  

SciTech Connect (OSTI)

Fast (MeV) molecular-ion beams provide a unique source of energetic projectile nuclei which are correlated in space and time. The recognition of this property has prompted several recent investigations of various aspects of the interactions of these ions with matter. High-resolution measurements on the fragments resulting from these interactions have already yielded a wealth of new information on such diverse topics as plasma oscillations in solids and stereochemical structures of molecular ions as well as a variety of atomic collision phenomena. The general features of several such experiments will be discussed and recent results will be presented.

Kanter, E.P.

1980-01-01T23:59:59.000Z

84

Temperature-dependent ion beam mixing  

SciTech Connect (OSTI)

Recent work on enhanced interdiffusion rates during ion-beam mixing at elevated temperatures is reviewed. As discussed previously, expected increase in ion-beam mixing rates due to `radiation-enhanced diffusion` (RED), i.e. the free migration of isolated vacancy and interstitial defects, is well documented in single-crystal specimens in the range of 0.4 to 0.6 of absolute melting temperature. In contrast, the increase often observed at somewhat lower temperatures during ion-beam mixing of polycrystalline specimens is not well understood. However, sufficient evidence is available to show that this increase reflects intracascade enhancement of a thermally-activated process that also occurs without irradiation. Recent evidence is presented which suggests that this process is Diffusion-induced Grain-Boundary Migration (DIGM). An important complementary conclusion is that because ion-beam mixing in single-crystal specimens exhibits no significant temperature dependence below that of RED, models that invoke only irradiation-specific phenomena, e.g., cascade-overlap, thermal-spikes, or liquid-diffusion, and hence which predict no difference in mixing behavior between single- or poly-crystalline specimens, cannot account for the existing results.

Rehn, L.E.; Alexander, D.E.

1993-08-01T23:59:59.000Z

85

Temporal and spatial study of neon ion emission from a plasma focus device  

SciTech Connect (OSTI)

The temporal and spatial characteristics of the neon ion beam emissions from a low energy plasma focus device have been studied by employing a multiple Faraday cup assembly and the CR-39 track detectors at different angular and axial positions. In addition, the operating gas pressures were also varied to study the temporal and spatial characteristics of the neon ion beam emissions. The Faraday cup analyses show that the ion flux strongly depends on the operating gas pressure as well as the angular positions. The estimated ion energy measurements at the aperture of the Faraday cup indicate that the plasma focus device is a source of polyenergetic ions ranging from approximately a few keV to a few hundreds of keV, irrespective of the angular positions. The exposed CR-39 detectors have shown the formation of multiple ion tracks with diameter ranging from 2 to 13 {mu}m. The populations of lower diameter tracks (2-6 {mu}m) are observed to be more at 0 deg. and 10 deg. angles. It is also noticed that the most populated track counts have shifted toward the higher diameter as the angular positions change from 0 deg. to 70 deg. The present study enables us to predict a clear picture of ion flux and energy distribution inside the plasma focus chamber that will help to use the device for material irradiation application in a more controlled manner.

Bhuyan, M.; Neog, N. K.; Mohanty, S. R. [Centre of Plasma Physics, Institute for Plasma Research, Sonapur, Kamrup 782402 (India); Rao, C. V. S. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Raole, P. M. [FCIPT, Institute for Plasma Research, Gandhinagar 342044 (India)

2011-03-15T23:59:59.000Z

86

Method of automatic measurement and focus of an electron beam and apparatus therefore  

DOE Patents [OSTI]

An electron beam focusing system, including a plural slit-type Faraday beam trap, for measuring the diameter of an electron beam and automatically focusing the beam for welding is disclosed. Beam size is determined from profiles of the current measured as the beam is swept over at least two narrow slits of the beam trap. An automated procedure changes the focus coil current until the focal point location is just below a workpiece surface. A parabolic equation is fitted to the calculated beam sizes from which optimal focus coil current and optimal beam diameter are determined. 12 figs.

Giedt, W.H.; Campiotti, R.

1996-01-09T23:59:59.000Z

87

H-mode accelerating structures with permanent-magnet quadrupole beam focusing  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

We have developed high-efficiency normal-conducting rf accelerating structures by combining H -mode resonator cavities and a transverse beam focusing by permanent-magnet quadrupoles (PMQ), for beam velocities in the range of a few percent of the speed of light. The shunt impedance of interdigital H -mode (IH-PMQ) structures is 10–20 times higher than that of a conventional drift-tube linac, while the transverse size is 4–5 times smaller. Results of the combined 3D modeling—electromagnetic computations, multiparticle beam-dynamics simulations with high currents, and thermal-stress analysis—for an IH-PMQ accelerator tank are presented. The accelerating-field profile in the tank is tuned to provide the best propagation of a 50-mA deuteron beam using coupled iterations of electromagnetic and beam-dynamics modeling. Measurements of a cold model of the IH-PMQ tank show a good agreement with the calculations. Examples of cross-bar H -mode structures with PMQ focusing for higher beam velocities are also presented. H -PMQ accelerating structures following a short radio-frequency quadrupole accelerator can be used both in the front end of ion linacs or in stand-alone applications.

Kurennoy, S. S.; Rybarcyk, L. J.; O’Hara, J. F.; Olivas, E. R.; Wangler, T. P.

2012-09-01T23:59:59.000Z

88

Effect of secondary ions on the electron beam optics in the Recycler Electron Cooler  

SciTech Connect (OSTI)

Antiprotons in Fermilab's Recycler ring are cooled by a 4.3 MeV, 0.1-0.5 A DC electron beam (as well as by a stochastic cooling system). The unique combination of the relativistic energy ({gamma} = 9.49), an Ampere-range DC beam, and a relatively weak focusing makes the cooling efficiency particularly sensitive to ion neutralization. A capability to clear ions was recently implemented by way of interrupting the electron beam for 1-30 {micro}s with a repetition rate of up to 40 Hz. The cooling properties of the electron beam were analyzed with drag rate measurements and showed that accumulated ions significantly affect the beam optics. For a beam current of 0.3 A, the longitudinal cooling rate was increased by factor of {approx}2 when ions were removed.

Shemyakin, A.; Prost, L.; Saewert, G.; /Fermilab

2010-05-01T23:59:59.000Z

89

Analysis of the optics of the Final Focus Test Beam using Lie algebra based techniques  

SciTech Connect (OSTI)

This report discusses the analysis of the beam optics of the final focus test beam at the Stanford Linear Collider using Lie algebra. (LSP).

Roy, G.J.

1992-09-01T23:59:59.000Z

90

Ion-beam apparatus and method for analyzing and controlling integrated circuits  

DOE Patents [OSTI]

An ion-beam apparatus and method for analyzing and controlling integrated circuits. The ion-beam apparatus comprises a stage for holding one or more integrated circuits (ICs); a source means for producing a focused ion beam; and a beam-directing means for directing the focused ion beam to irradiate a predetermined portion of the IC for sufficient time to provide an ion-beam-generated electrical input signal to a predetermined element of the IC. The apparatus and method have applications to failure analysis and developmental analysis of ICs and permit an alteration, control, or programming of logic states or device parameters within the IC either separate from or in combination with applied electrical stimulus to the IC for analysis thereof. Preferred embodiments of the present invention including a secondary particle detector and an electron floodgun further permit imaging of the IC by secondary ions or electrons, and allow at least a partial removal or erasure of the ion-beam-generated electrical input signal.

Campbell, Ann N. (Albuquerque, NM); Soden, Jerry M. (Placitas, NM)

1998-01-01T23:59:59.000Z

91

Ion-beam apparatus and method for analyzing and controlling integrated circuits  

DOE Patents [OSTI]

An ion-beam apparatus and method for analyzing and controlling integrated circuits are disclosed. The ion-beam apparatus comprises a stage for holding one or more integrated circuits (ICs); a source means for producing a focused ion beam; and a beam-directing means for directing the focused ion beam to irradiate a predetermined portion of the IC for sufficient time to provide an ion-beam-generated electrical input signal to a predetermined element of the IC. The apparatus and method have applications to failure analysis and developmental analysis of ICs and permit an alteration, control, or programming of logic states or device parameters within the IC either separate from or in combination with applied electrical stimulus to the IC for analysis thereof. Preferred embodiments of the present invention including a secondary particle detector and an electron floodgun further permit imaging of the IC by secondary ions or electrons, and allow at least a partial removal or erasure of the ion-beam-generated electrical input signal. 4 figs.

Campbell, A.N.; Soden, J.M.

1998-12-01T23:59:59.000Z

92

Beam halo formation from space-charge dominated beams in uniform focusing channels  

SciTech Connect (OSTI)

In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which results in a 2-component beam consisting of an inner core and an outer halo. The halo is very prominent in mismatched beams, and the potential for accelerator activation is of concern for a next generation of cw, high-power proton linacs that could be applied for intense neutron generators to process nuclear materials. We present new results about beam halo and the evolution of space-charge dominated beams from multiparticle simulation of initial laminar beams in a uniform linear focusing channel, and from a model consisting of single particle interactions with a uniform-density beam core. We study the energy gain from particle interactions with the space-charge field of the core, and we identify the resonant characteristic of this interaction as the basic cause of the separation of the beam into the two components. We identify three different particle-trajectory types, and we suggest that one of these types may lead to continuous halo growth, even after the halo is removed by collimators.

O'Connell, J.S. (Booz, Allen and Hamilton, Inc., Arlington, VA (United States)); Wangler, T.P.; Mills, R.S. (Los Alamos National Lab., NM (United States)); Crandall, K.R. (AccSys Technology, Inc., Pleasanton, CA (United States))

1993-01-01T23:59:59.000Z

93

Beam halo formation from space-charge dominated beams in uniform focusing channels  

SciTech Connect (OSTI)

In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which results in a 2-component beam consisting of an inner core and an outer halo. The halo is very prominent in mismatched beams, and the potential for accelerator activation is of concern for a next generation of cw, high-power proton linacs that could be applied for intense neutron generators to process nuclear materials. We present new results about beam halo and the evolution of space-charge dominated beams from multiparticle simulation of initial laminar beams in a uniform linear focusing channel, and from a model consisting of single particle interactions with a uniform-density beam core. We study the energy gain from particle interactions with the space-charge field of the core, and we identify the resonant characteristic of this interaction as the basic cause of the separation of the beam into the two components. We identify three different particle-trajectory types, and we suggest that one of these types may lead to continuous halo growth, even after the halo is removed by collimators.

O`Connell, J.S. [Booz, Allen and Hamilton, Inc., Arlington, VA (United States); Wangler, T.P.; Mills, R.S. [Los Alamos National Lab., NM (United States); Crandall, K.R. [AccSys Technology, Inc., Pleasanton, CA (United States)

1993-06-01T23:59:59.000Z

94

Simulating Electron Effects in Heavy-Ion Accelerators with Solenoid Focusing  

SciTech Connect (OSTI)

Contamination from electrons is a concern for solenoid-focused ion accelerators being developed for experiments in high-energy-density physics. These electrons, produced directly by beam ions hitting lattice elements or indirectly by ionization of desorbed neutral gas, can potentially alter the beam dynamics, leading to a time-varying focal spot, increased emittance, halo, and possibly electron-ion instabilities. The electrostatic particle-in-cell code WARP is used to simulate electron-cloud studies on the solenoid-transport experiment (STX) at Lawrence Berkeley National Laboratory. We present self-consistent simulations of several STX configurations and compare the results with experimental data in order to calibrate physics parameters in the model.

Sharp, W. M.; Grote, D. P.; Cohen, R. H.; Friedman, A.; Molvik, A. W.; Vay, J.-L.; Seidl, P. A.; Roy, P. K.; Coleman, J. E.; Haber, I.

2007-06-20T23:59:59.000Z

95

Phase transition oscillations induced by a strongly focused laser beam  

E-Print Network [OSTI]

We report here the observation of a surprising phenomenon consisting in a oscillating phase transition which appears in a binary mixture, PMMA/3-octanone, when this is enlightened by a strongly focused infrared laser beam. PMMA/3-octanone has a UCST (Upper Critical Solution Temperature) which presents a critical point at temperature Tc = 306.6 K and volume fraction $\\phi$c = 12.8 % [Crauste et al., ArXiv 1310.6720, 2012]. This oscillatory phenomenon appears because of thermophoretic and electrostriction effects and non-linear diffusion. We analyze these oscillations and we propose a simple model which includes the minimal ingredients to produce the oscillatory behavior. Phase transitions in binary mixtures are still a widely studied subject, specifically near the critical point where several interesting and not completely understood phenomena may appear, among them we recall the critical Casimir forces [2],[3], confinement effects [4], [5] and out-of-equilibrium dynamics after a quench. The perturbation of the binary mixtures by mean of external fields is also an important and recent field of investigation [6]. For example, a laser can induce interesting phenomena in demixing binary mixtures because the radiation pressure can deform the interface between the two phases and it can be used to measure the interface tension [7]. Depending on the nature of the binary mixtures, laser illumination can also lead to a mixing or demixing transition. In ref.[8], focused infrared laser light heats the medium initially in the homogeneous phase and causes a separation in the LCST (Low Critical Solution Temperature) system. The radiation pressure gradients in a laser beam also contribute in the aggregation of polymers , thus producing a phase transition. The local heating may induce thermophoretic forces which attract towards the laser beam one of the binary-mixture components [9]. Other forces like electrostriction can also be involved [10]. In this letter, we report a new phenomenon, which consists in an oscillating phase transition induced by a constant illumination from an infrared laser beam in the heterogeneous region of an UCST (Upper Critical Solution Temperature) binary mixture. Oscillation phenomena in phase transition have already been reported in slow cooling UCST [11],[12] but as far as we know, never induced by a stationary laser illumination. After describing our experimental setup , we will present the results. Then we will use a very simplified model which contains the main necessary physical ingredients to induce this oscillation phenomenon.

Clémence Devailly; Caroline Crauste-Thibierge; Artyom Petrosyan; Sergio Ciliberto

2015-03-10T23:59:59.000Z

96

Performance and Controllability of Pulsed Ion Beam Ablation Propulsion  

SciTech Connect (OSTI)

We propose novel propulsion driven by ablation plasma pressures produced by the irradiation of pulsed ion beams onto a propellant. The ion beam ablation propulsion demonstrates by a thin foil (50 {mu}mt), and the flyer velocity of 7.7 km/s at the ion beam energy density of 2 kJ/cm2 adopted by using the Time-of-flight method is observed numerically and experimentally. We estimate the performance of the ion beam ablation propulsion as specific impulse of 3600 s and impulse bit density of 1700 Ns/m2 obtained from the demonstration results. In the numerical analysis, a one-dimensional hydrodynamic model with ion beam energy depositions is used. The control of the ion beam kinetic energy is only improvement of the performance but also propellant consumption. The spacecraft driven by the ion beam ablation provides high performance efficiency with short-pulsed ion beam irradiation. The numerical results of the advanced model explained latent heat and real gas equation of state agreed well with experimental ones over a wide range of the incident ion beam energy density.

Yazawa, Masaru; Buttapeng, Chainarong; Harada, Nobuhiro [Nagaoka University of Technology, Department of Electrical Engineering, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi [Nagaoka University of Technology, Extreme Energy-Density Research Institute, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan)

2006-05-02T23:59:59.000Z

97

Progress on Plasma Lens Experiment at the Final Focus Test Beam *  

E-Print Network [OSTI]

Progress on Plasma Lens Experiment at the Final Focus Test Beam * S. Chattopadhyay 1 , P. Chen 2 Collaboration proposed and has been approved to perform the Plasma Lens Experiment at the Final Focus Test Beam of the experiment are to study plasma focusing of high energy, high density particle beams; to investigate plasma

98

Beam-Dynamics Studies and Advanced Accelerator Research at CTF-3 Compact Final Focus, Laser Compton Scattering, Plasmas, etc.  

E-Print Network [OSTI]

Preliminary investigations are summarized on the possible use of the CTF3 facility for extended beam-dynamics studies and advanced accelerator R&D, which would exploit its unique properties and beam availability. The key element of these considerations is the possible addition of a test beam-delivery system comprising a compact final focus and advanced collimation concepts, scaled from 3 TeV down to low energy and having a short total length. Operational experience, verification of critical questions (octupole tail folding, beam halo transport, etc.), diagnostics (e.g., rf BPMs) and stabilization could all be explored in such a facility, which would benefit not only the CLIC study, but all linear collider projects. Another interesting application would be the study of plasma-beam interaction, which may include plasma focusing, plasma acceleration, ion-channel radiation, and plasma wigglers.

Assmann, R W; Burkhardt, H; Corsini, R; Faus-Golfe, A; Gronberg, J; Redaelli, S; Schulte, Daniel; Velasco, M; Zimmermann, Frank

2002-01-01T23:59:59.000Z

99

Terahertz generation by two cross focused laser beams in collisional plasmas  

SciTech Connect (OSTI)

The role of two cross-focused spatial-Gaussian laser beams has been studied for the high power and efficient terahertz (THz) radiation generation in the collisional plasma. The nonlinear current at THz frequency arises on account of temperature dependent collision frequency of electrons with ions in the plasma and the presence of a static electric field (applied externally in the plasma) and density ripple. Optimisation of laser-plasma parameters gives the radiated THz power of the order of 0.23??MW.

Sharma, R. P., E-mail: rpsharma@ces.iitd.ernet.in; Singh, Ram Kishor, E-mail: ram007kishor@gmail.com [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi 110016 (India)

2014-07-15T23:59:59.000Z

100

Mechanical and tribological properties of ion beam-processed surfaces  

SciTech Connect (OSTI)

The intent of this work was to broaden the applications of well-established surface modification techniques and to elucidate the various wear mechanisms that occur in sliding contact of ion-beam processed surfaces. The investigation included characterization and evaluation of coatings and modified surfaces synthesized by three surface engineering methods; namely, beam-line ion implantation, plasma-source ion implantation, and DC magnetron sputtering. Correlation among measured properties such as surface hardness, fracture toughness, and wear behavior was also examined. This dissertation focused on the following areas of research: (1) investigating the mechanical and tribological properties of mixed implantation of carbon and nitrogen into single crystal silicon by beam-line implantation; (2) characterizing the mechanical and tribological properties of diamond-like carbon (DLC) coatings processed by plasma source ion implantation; and (3) developing and evaluating metastable boron-carbon-nitrogen (BCN) compound coatings for mechanical and tribological properties. The surface hardness of a mixed carbon-nitrogen implant sample improved significantly compared to the unimplanted sample. However, the enhancement in the wear factor of this sample was found to be less significant than carbon-implanted samples. The presence of nitrogen might be responsible for the degraded wear behavior since nitrogen-implantation alone resulted in no improvement in the wear factor. DLC coatings have low friction, low wear factor, and high hardness. The fracture toughness of DLC coatings has been estimated for the first time. The wear mechanism in DLC coatings investigated with a ruby slider under a contact stress of 1 GPa was determined to be plastic deformation. The preliminary data on metastable BCN compound coatings indicated high friction, low wear factor, and high hardness.

Kodali, P.

1998-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Extraction of highly charged ions from the electron beam ion trap at LBNL for applications in surface analysis and Materials Science  

E-Print Network [OSTI]

Electron Beam Ion Trap at LBNL for Applications in Surfacetransferred from LLNL to LBNL, and is now operating with+ . The research program at LBNL is focused on the following

2001-01-01T23:59:59.000Z

102

Flyer Acceleration by Pulsed Ion Beam Ablation and Application for Space Propulsion  

SciTech Connect (OSTI)

Flyer acceleration by ablation plasma pressure produced by irradiation of intense pulsed ion beam has been studied. Acceleration process including expansion of ablation plasma was simulated based on fluid model. And interaction between incident pulsed ion beam and a flyer target was considered as accounting stopping power of it. In experiments, we used ETIGO-II intense pulsed ion beam generator with two kinds of diodes; 1) Magnetically Insulated Diode (MID, power densities of <100 J/cm2) and 2) Spherical-focused Plasma Focus Diode (SPFD, power densities of up to 4.3 kJ/cm2). Numerical results of accelerated flyer velocity agreed well with measured one over wide range of incident ion beam energy density. Flyer velocity of 5.6 km/s and ablation plasma pressure of 15 GPa was demonstrated by the present experiments. Acceleration of double-layer target consists of gold/aluminum was studied. For adequate layer thickness, such a flyer target could be much more accelerated than a single layer. Effect of waveform of ion beam was also examined. Parabolic waveform could accelerate more efficiently than rectangular waveform. Applicability of ablation propulsion was discussed. Specific impulse of 7000{approx}8000 seconds and time averaged thrust of up to 5000{approx}6000N can be expected. Their values can be controllable by changing power density of incident ion beam and pulse duration.

Harada, Nobuhiro; Buttapeng, Chainarong; Yazawa, Masaru [Department of Electrical Engineering, Nagaoka University of Technology, 1603 Kamitomioka, Nagaoka 940-2188 (Japan); Kashine, Kenji [Department of Electrical and Electronic Engineering, Kagoshima National College of Technology, 1460-1 Shinko, Hayato-cho, Aira-gun, Kagoshima 899-5193 (Japan); Jiang Weihua; Yatsui, Kiyoshi [Extreme Energy Density Research Institute, Nagaoka University of Technology, 1603 Kamitomioka, Nagaoka 940-2188 (Japan)

2004-02-04T23:59:59.000Z

103

Project Execution Plan Electron Beam Ion Source Project  

E-Print Network [OSTI]

Project Execution Plan for the Electron Beam Ion Source Project (EBIS) Project # 07-SC-02 at Brookhaven National Laboratory Upton, NY For the U.S. Department of Energy Office of Science Office of Nuclear Physics (SC ­ 26) Rev. 1 May 2008 #12;#12;#12;4 Project Execution Plan for the Electron Beam Ion

104

Production of multiply charged ion beams from solid substances with the mVINIS ion source  

SciTech Connect (OSTI)

The mVINIS ion source has enabled us to obtain multiply charged ion beams from gases as well as from solid materials. The solid substance ion beams were produced by using two techniques: (a) the evaporation of metals by using the inlet system based on a minioven and (b) the metal-ions-from-volatile-compounds method (MIVOC) by using the modified gas inlet system. Great efforts were made in the production of high current stable ion beams of solids with relatively high melting points (over 1000 deg. C). The B{sup 3+} ion-beam current of over 300 {mu}A was one of the most intensive beams extracted until now. The obtained multiply charged ion-beam spectra of solid substances (B, Fe, and Zn) are presented as well as some of the corresponding experimental results achieved during the modification of polymers, carbon materials, and fullerenes.

Draganic, I.; Dobrosavljevic, A.; Nedeljkovic, T.; Siljegovic, M. [Laboratory of Physics, Vinca Institute of Nuclear Sciences, P.O. Box. 522, 11000 Belgrade (Serbia and Montenegro)

2006-03-15T23:59:59.000Z

105

Ion Beam Deposition of Thin Films: Growth Processes and Nanostructure Formation  

SciTech Connect (OSTI)

Ion beam deposition is a process far from thermodynamic equilibrium and is in particular suited to grow metastable thin films with diamond-like properties, such as tetrahedral amorphous carbon (ta-C) and cubic boron nitride (c-BN). In this contribution the atomistic description of the deposition and growth processes are reviewed and compared to experimental results, obtained from mass selected ion beam deposition. The focus will be set to the nucleation and growth processes of boron nitride as a model system for ion based thin film formation. Furthermore, recent examples for nanostructure formation in ion deposited compound thin films will be presented. Ion beam deposited metal-carbon nano-composite thin films exhibit a variety of different morphologies such as rather homogeneous nanocluster distributions embedded in an a-C matrix, but also the self-organized formation of nanoscale multilayer structures.

Hofsaess, Hans C. [II. Physikalisches Institut, Universitaet Goettingen, Friedrich-Hund-Platz 1, D-37077 Goettingen (Germany)

2004-12-01T23:59:59.000Z

106

PLASMA FOCUSING OF HIGH ENERGY DENSITY ELECTRON AND POSITRON BEAMS \\Lambda  

E-Print Network [OSTI]

PLASMA FOCUSING OF HIGH ENERGY DENSITY ELECTRON AND POSITRON BEAMS \\Lambda J.S.T. Ng, P. Chen, W, for the first time, positron beams. We also discuss measure­ ments on plasma lens­induced synchrotron radiation and laser­ and beam­plasma interactions. 1 INTRODUCTION The plasma lens was proposed as a final focusing

107

Design and operation of the electron beam ion trap  

SciTech Connect (OSTI)

This report describes the basic features and operating principles of the Electron Beam Ion Trap. The differences between EBIT and other sources of highly charged ions are outlined. Its features and operating parameters are discussed. The report also explains why certain design choices were necessary and the constraints involved in building an electron beam ion trap. EBIT's evaporation cooling system is described in detail. 13 refs., 8 figs.

Vogel, D.

1990-05-30T23:59:59.000Z

108

EXTRACTION COMPRESSION AND ACCELERATION OF HIGH LINE CHARGE DENSITY ION BEAMS  

E-Print Network [OSTI]

on compression of heavy ion beams for creating high energyet al, “Highly Compressed Ion Beams for High Energy DensityPulsed Solenoid for Intense Ion Beam Transport,” these Proc:

Henestroza, E.

2008-01-01T23:59:59.000Z

109

E-Print Network 3.0 - atomic ion beams Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ion beams Search Powered by Explorit Topic List Advanced Search Sample search results for: atomic ion beams Page: << < 1 2 3 4 5 > >> 1 he Ion Beam Materials Laboratory (IBML) is a...

110

E-Print Network 3.0 - advanced ion beam Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

System 12;1. Ions from radio frequency (RF) ion source... to eliminate unwanted ion beams and to limit size of beam entering bending magnet 3. Main beam stop used... magnet is...

111

Phase transition oscillations induced by a strongly focused laser beam  

E-Print Network [OSTI]

We report here the observation of a surprising phenomenon consisting in a oscillating phase transition which appears in a binary mixture, PMMA/3-octanone, when this is enlightened by a strongly focused infrared laser beam. PMMA/3-octanone has a UCST (Upper Critical Solution Temperature) which presents a critical point at temperature Tc = 306.6 K and volume fraction $\\phi$c = 12.8 % [Crauste et al., ArXiv 1310.6720, 2012]. This oscillatory phenomenon appears because of thermophoretic and electrostriction effects and non-linear diffusion. We analyze these oscillations and we propose a simple model which includes the minimal ingredients to produce the oscillatory behavior. Phase transitions in binary mixtures are still a widely studied subject, specifically near the critical point where several interesting and not completely understood phenomena may appear, among them we recall the critical Casimir forces [2],[3], confinement effects [4], [5] and out-of-equilibrium dynamics after a quench. The perturbation of th...

Devailly, Clémence; Petrosyan, Artyom; Ciliberto, Sergio

2015-01-01T23:59:59.000Z

112

Method and apparatus for efficient photodetachment and purification of negative ion beams  

DOE Patents [OSTI]

Methods and apparatus are described for efficient photodetachment and purification of negative ion beams. A method of purifying an ion beam includes: inputting the ion beam into a gas-filled multipole ion guide, the ion beam including a plurality of ions; increasing a laser-ion interaction time by collisional cooling the plurality of ions using the gas-filled multipole ion guide, the plurality of ions including at least one contaminant; and suppressing the at least one contaminant by selectively removing the at least one contaminant from the ion beam by electron photodetaching at least a portion of the at least one contaminant using a laser beam.

Beene, James R. (Oak Ridge, TN) [Oak Ridge, TN; Liu, Yuan (Knoxville, TN) [Knoxville, TN; Havener, Charles C. (Knoxville, TN) [Knoxville, TN

2008-02-26T23:59:59.000Z

113

Status of Beta Beam R&D: Radioactive ion production  

E-Print Network [OSTI]

Status of Beta Beam R&D: Radioactive ion production O b h lf f EURISOL DS*/ISOLDE CERN Etam NOAH Infrastructure Action Structuring the European Research Area" g , y , Status of BetaBeam R&D AHIPA09 etam Status of BetaBeam R&D AHIPA09 etam.noah@esss.se #12;Introduction to betabeams Beta-beam proposal

McDonald, Kirk

114

Ion beam collimating grid to reduce added defects  

DOE Patents [OSTI]

A collimating grid for an ion source located after the exit grid. The collimating grid collimates the ion beamlets and disallows beam spread and limits the beam divergence during transients and steady state operation. The additional exit or collimating grid prevents beam divergence during turn-on and turn-off and prevents ions from hitting the periphery of the target where there is re-deposited material or from missing the target and hitting the wall of the vessel where there is deposited material, thereby preventing defects from being deposited on a substrate to be coated. Thus, the addition of a collimating grid to an ion source ensures that the ion beam will hit and be confined to a specific target area.

Lindquist, Walter B. (Oakland, CA); Kearney, Patrick A. (Livermore, CA)

2003-01-01T23:59:59.000Z

115

Spontaneous ion beam formation in the laboratory, space, and simulation  

SciTech Connect (OSTI)

We present experimental evidence for the spontaneous formation of multiple double layers within a single divergent magnetic field structure. Downstream of the divergent magnetic field, multiple accelerated ion populations are observed. The similarity of the accelerated ion populations observed in these laboratory experiments to ion populations observed in the magnetosphere and in numerical simulations suggests that the observation of a complex ion velocity distribution alone is insufficient to distinguish between simple plasma expansion and magnetic reconnection. Further, the effective temperature of the aggregate ion population is significantly larger than the temperatures of the individual ion population components, suggesting that insufficiently resolved measurements could misidentify multiple beam creation as ion heating. Ions accelerated in randomly oriented electric fields that mimic heating would have an ion heating rate dependent on the ion charge and mass that is qualitatively consistent with recent experimental observations of ion heating during magnetic reconnection.

Carr, J. Jr.; Cassak, P. A.; Galante, M.; Keesee, A. M.; Lusk, G.; Magee, R. M.; McCarren, D.; Scime, E. E.; Sears, S.; Vandervort, R. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States)] [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States); Gulbrandsen, N. [University of Tromsø, Tromsø (Norway)] [University of Tromsø, Tromsø (Norway); Goldman, Martin; Newman, David [Department of Physics, University of Colorado–Boulder, Boulder, Colorado 80309 (United States)] [Department of Physics, University of Colorado–Boulder, Boulder, Colorado 80309 (United States); Eastwood, J. P. [The Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom)] [The Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom)

2013-07-15T23:59:59.000Z

116

The Heavy Ion Fusion Science Virtual National Laboratory Status of heavy-ion-beam-driven  

E-Print Network [OSTI]

-see http://videos.komando.com/2008/08/19/water-painting/]. #12;12/7/08 The Heavy Ion Fusion Science Virtual12/7/08 The Heavy Ion Fusion Science Virtual National Laboratory 1 Status of heavy-ion-beam-driven high energy density physics and fusion* Presented by B. Grant Logan on behalf of the U.S. Heavy Ion

117

Nonlinear plasma waves excitation by intense ion beams in background plasma  

E-Print Network [OSTI]

describe the plasma perturbations well.5 Here, we focus on the general case where the plasma density hasNonlinear plasma waves excitation by intense ion beams in background plasma Igor D. Kaganovich, Edward A. Startsev, and Ronald C. Davidson Plasma Physics Laboratory, Princeton University, Princeton

Kaganovich, Igor

118

Physics with energetic radioactive ion beams  

SciTech Connect (OSTI)

Beams of short-lived, unstable nuclei have opened new dimensions in studies of nuclear structure and reactions. Such beams also provide key information on reactions that take place in our sun and other stars. Status and prospects of the physics with energetic radioactive beams are summarized.

Henning, W.F.

1996-12-31T23:59:59.000Z

119

Etching of Graphene Devices with a Helium Ion Beam  

E-Print Network [OSTI]

We report on the etching of graphene devices with a helium ion beam, including in situ electrical measurement during lithography. The etching process can be used to nanostructure and electrically isolate different regions ...

Baugher, Britton William Herb

120

anaconda ion beam: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Index 1 Ion beam CiteSeer Summary: Fast ignition is a method to decrease the energy of a fusion driver 1. At first the matter becomes compressed to high densities due to the...

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Development of a Negative Hydrogen Ion Source for Spatial Beam Profile Measurement of a High Intensity Positive Ion Beam  

SciTech Connect (OSTI)

We have been developing a negative hydrogen ion (H{sup -} ion) source for a spatial beam profile monitor of a high intensity positive ion beam as a new diagnostic tool. In case of a high intensity continuous-wave (CW) deuteron (D{sup +}) beam for the International Fusion Materials Irradiation Facility (IFMIF), it is difficult to measure the beam qualities in the severe high radiation environment during about one-year cyclic operation period. Conventional techniques are next to unusable for diagnostics in the operation period of about eleven months and for maintenance in the one-month shutdown period. Therefore, we have proposed an active beam probe system by using a negative ion beam and started an experimental study for the proof-of-principle (PoP) of the new spatial beam profile monitoring tool. In this paper, we present the status of development of the H{sup -} ion source as a probe beam source for the PoP experiment.

Shinto, Katsuhiro [Japan Atomic Energy Agency (JAEA), Rokkasho, Aomori 039-3212 (Japan); Wada, Motoi; Nishida, Tomoaki; Demura, Yasuhiro; Sasaki, Daichi [Doshisha University, Kyotanabe, Kyoto 610-0394 (Japan); Tsumori, Katsuyoshi; Nishiura, Masaki; Kaneko, Osamu [National Institute for Fusion Science (NIFS), Toki, Gifu 509-5292 (Japan); Kisaki, Masashi; Sasao, Mamiko [Tohoku University, Aoba, Sendai, Miyagi 980-8579 (Japan)

2011-09-26T23:59:59.000Z

122

Stationary self-focusing of intense laser beam in cold quantum plasma using ramp density profile  

SciTech Connect (OSTI)

By using a transient density profile, we have demonstrated stationary self-focusing of an electromagnetic Gaussian beam in cold quantum plasma. The paper is devoted to the prospects of using upward increasing ramp density profile of an inhomogeneous nonlinear medium with quantum effects in self-focusing mechanism of high intense laser beam. We have found that the upward ramp density profile in addition to quantum effects causes much higher oscillation and better focusing of laser beam in cold quantum plasma in comparison to that in the classical relativistic case. Our computational results reveal the importance and influence of formation of electron density profiles in enhancing laser self-focusing.

Habibi, M. [Department of Physics, Shirvan Branch, Islamic Azad University, Shirvan (Iran, Islamic Republic of); Ghamari, F. [Department of Physics, Khorramabad Branch, Islamic Azad University, Khorramabad (Iran, Islamic Republic of)

2012-10-15T23:59:59.000Z

123

Suppression of Beam-Ion Instability in Electron Rings with Multi-Bunch Train Beam Fillings  

SciTech Connect (OSTI)

The ion-caused beam instability in the future light sources and electron damping rings can be serious due to the high beam current and ultra-small emittance of picometer level. One simple and effective mitigation of the instability is a multi-bunch train beam filling pattern which can significantly reduce the ion density near the beam, and therefore reduce the instability growth rate up to two orders of magnitude. The suppression is more effective for high intensity beams with low emittance. The distribution and the field of trapped ions are benchmarked to validate the model used in the paper. The wake field of ion-cloud and the beam-ion instability is investigated both analytically and numerically. We derived a simple formula for the build-up of ion-cloud and instability growth rate with the multi-bunch-train filling pattern. The ion instabilities in ILC damping ring, SuperKEKB and SPEAR3 are used to compare with our analyses. The analyses in this paper agree well with simulations.

Wang, L.; Cai, Y.; Raubenheimer, T.O.; /SLAC; Fukuma, H.; /KEK, Tsukuba

2011-08-18T23:59:59.000Z

124

A compact, versatile low-energy electron beam ion source  

SciTech Connect (OSTI)

A new compact Electron Beam Ion Source, the Dresden EBIT-LE, is introduced as an ion source working at low electron beam energies. The EBIT-LE operates at an electron energy ranging from 100 eV to some keV and can easily be modified to an EBIT also working at higher electron beam energies of up to 15 keV. We show that, depending on the electron beam energy, electron beam currents from a few mA in the low-energy regime up to about 40 mA in the high-energy regime are possible. Technical solutions as well as first experimental results of the EBIT-LE are presented. In ion extraction experiments, a stable production of low and intermediate charged ions at electron beam energies below 2 keV is demonstrated. Furthermore, X-ray spectroscopy measurements confirm the possibility of using the machine as a source of X-rays from ions excited at low electron energies.

Zschornack, G., E-mail: g.zschornack@hzdr.de [Department of Physics, Dresden University of Technology, 01062 Dresden, Germany and Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, 01328 Dresden (Germany); König, J.; Schmidt, M.; Thorn, A. [DREEBIT GmbH, 01109 Dresden (Germany)] [DREEBIT GmbH, 01109 Dresden (Germany)

2014-02-15T23:59:59.000Z

125

Fusion Induced by Radioactive Ion Beams  

E-Print Network [OSTI]

The use of radioactive beams opens a new frontier for fusion studies. The coupling to the continuum can be explored with very loosely bound nuclei. Experiments were performed with beams of nuclei at or near the proton and neutron drip-lines to measure fusion and associated reactions in the vicinity of the Coulomb barrier. In addition, the fusion yield is predicted to be enhanced in reactions involving very neutron-rich unstable nuclei. Experimental measurements were carried out to investigate if it is feasible to use such beams to produce new heavy elements. The current status of these experimental activities is given in this review.

J. F. Liang; C. Signorini

2005-04-26T23:59:59.000Z

126

Emittance growth of an nonequilibrium intense electron beam in a transport channel with discrete focusing  

SciTech Connect (OSTI)

The author analyzes the emittance growth mechanisms for a continuous, intense electron beam in a focusing transport channel, over distances short enough that the beam does not reach equilibrium. The emittance grows from the effect of nonlinear forces arising from (1) current density nonuniformities, (2) energy variations leading to nonlinearities in the space-charge force even if the current density is uniform, (3) axial variations in the radial vector potential, (4) an axial velocity shear along the beam, and (5) an energy redistribution of the beam as the beam compresses or expands. The emittance growth is studied analytically and numerically for the cases of balanced flow, tight focusing, and slight beam scalloping, and is additionally studied numerically for an existing 6-MeV induction linear accelerator. Rules for minimizing the emittance along a beamline are established. Some emittance growth will always occur, both from current density nonuniformities that arise along the transport and from beam radius changes along the transport.

Carlsten, B.E.

1997-02-01T23:59:59.000Z

127

Ion beam driven ion-acoustic waves in a plasma cylinder with negatively charged dust grains  

SciTech Connect (OSTI)

An ion beam propagating through a magnetized potassium plasma cylinder having negatively charged dust grains drives electrostatic ion-acoustic waves to instability via Cerenkov interaction. The phase velocity of sound wave increases with the relative density of negatively charged dust grains. The unstable wave frequencies and the growth rate increase, with the relative density of negatively charged dust grains. The growth rate of the unstable mode scales as one-third power of the beam density. The real part of frequency of the unstable mode increases with the beam energy and scales as almost the one-half power of the beam energy.

Sharma, Suresh C.; Walia, Ritu [Department of Physics, Maharaja Agrasen Institute of Technology, PSP Area Plot No.-1, Sector-22, Rohini, Delhi 110 086 (India); Sharma, Kavita [Department of Physics, Bhagwan Parshuram Institute of Technology, Sector-17, Rohini, New Delhi 110 089 (India)

2012-07-15T23:59:59.000Z

128

Improved production of N{sup +} ions from a multicusp ion beam apparatus  

SciTech Connect (OSTI)

This invention is comprised of a method of generating a high purity (at least 98%) N{sup +} ion beam using a multicusp ion source having a chamber formed by a cylindrical chamber wall surrounded by a plurality of magnets, a filament centrally disposed in said chamber, a plasma electrode having an extraction orifice at one end of the chamber, a magnetic filter having two parallel magnets spaced from said plasma electrode and dividing the chamber into arc discharge and extraction regions. The method includes ionizing nitrogen gas in the arc discharge region of the chamber, maintaining the chamber wall at a positive voltage relative to the filament and at a magnitude for an optimum percentage of N{sup +} ions in the extracted ion beam, disposing a hot liner within the chamber and near the chamber wall to limit recombination of N{sup +} ions into the N{sub 2}{sup +} ions, spacing the magnets of the magnetic filter from each other for optimum percentage of N{sup +} ions in the extracted ion beams, and maintaining a relatively low pressure downstream of the extraction orifice and of a magnitude (preferably within the range of 3--8 {times} 10{sup {minus}4} torr) for an optimum percentage of N{sup +} ions in the extracted ion beam.

Leung, Ka-Ngo; Kunkel, W.B.; Walther, S.R.

1991-12-31T23:59:59.000Z

129

Use of radial self-field geometry for intense pulsed ion beam generation above 6 MeV on Hermes III.  

SciTech Connect (OSTI)

We investigate the generation and propagation of intense pulsed ion beams at the 6 MeV level and above using the Hermes III facility at Sandia National Laboratories. While high-power ion beams have previously been produced using Hermes III, we have conducted systematic studies of several ion diode geometries for the purpose of maximizing focused ion energy for a number of applications. A self-field axial-gap diode of the pinch reflex type and operated in positive polarity yielded beam power below predicted levels. This is ascribed both to power flow losses of unknown origin upstream of the diode load in Hermes positive polarity operation, and to anomalies in beam focusing in this configuration. A change to a radial self-field geometry and negative polarity operation resulted in greatly increased beam voltage (> 6 MeV) and estimated ion current. A comprehensive diagnostic set was developed to characterize beam performance, including both time-dependent and time-integrated measurements of local and total beam power. A substantial high-energy ion population was identified propagating in reverse direction, i.e. from the back side of the anode in the electron beam dump. While significant progress was made in increasing beam power, further improvements in assessing the beam focusing envelope will be required before ultimate ion generation efficiency with this geometry can be completely determined.

Renk, Timothy Jerome; Harper-Slaboszewicz, Victor Jozef; Ginn, William Craig; Mikkelson, Kenneth A.; Schall, Michael; Cooper, Gary Wayne

2012-12-01T23:59:59.000Z

130

Plasma and Ion Beam Injection into an FRC  

SciTech Connect (OSTI)

Experiments on the transverse injection of intense (5-20 A/cm{sup 2}), wide cross-section (10-cm), neutralized, {approx}100-eV H{sup +} plasma and 100-keV H{sup +} ion beams into a preformed B-field reversed configuration (FRC) are described. The FRC background plasma temperature was {approx}5 eV with densities of {approx}10{sup 13} cm{sup -3}. In contrast to earlier experiments, the background plasma was generated by separate plasma gun arrays. For the startup of the FRC, a betatron-type 'slow' coaxial source was used. Injection of the plasma beam into the preformed FRC resulted in a 30-40% increase of the FRC lifetime and the amplitude of the reversed magnetic field. As for the ion beam injection experiment into the preformed FRC, there was evidence of beam capture within the configuration.

Anderson, M.; Bystritskii, V.; Garate, E.; Rostoker, N.; Song, Y.; Drie, A. van [Department of Physics and Astronomy, University of California at Irvine, CA, 92697 (United States); Binderbauer, M. [Tri Alpha Energy Inc., Foothill Ranch, CA, 92610 (United States); Isakov, I. [Institute of High Voltage Technology, Tomsk, 634050 (Russian Federation)

2005-10-15T23:59:59.000Z

131

ELECTRON BEAM ION SOURCE PREINJECTOR PROJECT (EBIS) CONCEPTUAL DESIGN REPORT.  

SciTech Connect (OSTI)

This report describes a new heavy ion pre-injector for the Relativistic Heavy Ion Collider (RHIC) based on a high charge state Electron Beam Ion Source (EBIS), a Radio Frequency Quadrupole (RFQ) accelerator, and a short Linac. The highly successful development of an EBIS at BNL now makes it possible to replace the present pre-injector that is based on an electrostatic Tandem with a reliable, low maintenance Linac-based pre-injector. Linac-based pre-injectors are presently used at most accelerator and collider facilities with the exception of RHIC, where the required gold beam intensities could only be met with a Tandem until the recent EBIS development. EBIS produces high charge state ions directly, eliminating the need for the two stripping foils presently used with the Tandem. Unstable stripping efficiencies of these foils are a significant source of luminosity degradation in RHIC. The high reliability and flexibility of the new Linac-based pre-injector will lead to increased integrated luminosity at RHIC and is an essential component for the long-term success of the RHIC facility. This new pre-injector, based on an EBIS, also has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium beams and, as part of a future upgrade, might also be used to produce polarized {sup 3}He beams. These capabilities will be critical to the future luminosity upgrades and electron-ion collisions in RHIC. The new RFQ and Linac that are used to accelerate beams from the EBIS to an energy sufficient for injection into the Booster are both very similar to existing devices already in operation at other facilities. Injection into the Booster will occur at the same location as the existing injection from the Tandem.

ALESSI, J.; BARTON, D.; BEEBE, E.; GASSNER, D.; ET AL.

2005-02-28T23:59:59.000Z

132

Slit disk for modified faraday cup diagnostic for determining power density of electron and ion beams  

DOE Patents [OSTI]

A diagnostic system for characterization of an electron beam or an ion beam includes an electrical conducting disk of refractory material having a circumference, a center, and a Faraday cup assembly positioned to receive the electron beam or ion beam. At least one slit in the disk provides diagnostic characterization of the electron beam or ion beam. The at least one slit is located between the circumference and the center of the disk and includes a radial portion that is in radial alignment with the center and a portion that deviates from radial alignment with the center. The electron beam or ion beam is directed onto the disk and translated to the at least one slit wherein the electron beam or ion beam enters the at least one slit for providing diagnostic characterization of the electron beam or ion beam.

Teruya, Alan T. (Livermore, CA); Elmer; John W. (Danville, CA); Palmer, Todd A. (State College, PA)

2011-03-08T23:59:59.000Z

133

Simulation of adiabatic thermal beams in a periodic solenoidal magnetic focusing field  

E-Print Network [OSTI]

Self-consistent particle-in-cell simulations are performed to verify earlier theoretical predictions of adiabatic thermal beams in a periodic solenoidal magnetic focusing field [ K.?R. Samokhvalova, J. Zhou and C. Chen ...

Barton, T. J.

134

Means for the focusing and acceleration of parallel beams of charged particles. [Patent application  

DOE Patents [OSTI]

Apparatus for focusing beams of charged particles comprising planar arrays of electrostatic quadrupoles. The array may be assembled from a single component which comprises a support plate containing uniform rows of poles. Each pole is separated by a hole through the plate designed to pass a beam. Two such plates may be positioned with their poles intermeshed to form a plurality of quadrupoles.

Maschke, A.W.

1980-09-23T23:59:59.000Z

135

ELECTRON BEAM ION SOURCE PREINJECTOR PROJECT (EBIS) CONCEPTUAL DESIGN REPORT.  

SciTech Connect (OSTI)

This report describes a new heavy ion pre-injector for the Relativistic Heavy Ion Collider (RHIC) based on a high charge state Electron Beam Ion Source (EBIS), a Radio Frequency Quadrupole (RFQ) accelerator, and a short Linear accelerator (Linac). The highly successful development of an EBIS at Brookhaven National Laboratory (BNL) now makes it possible to replace the present pre-injector that is based on an electrostatic Tandem with a reliable, low maintenance Linac-based pre-injector. Linac-based preinjectors are presently used at most accelerator and collider facilities with the exception of RHIC, where the required gold beam intensities could only be met with a Tandem until the recent EBIS development. EBIS produces high charge state ions directly, eliminating the need for the two stripping foils presently used with the Tandem. Unstable stripping efficiencies of these foils are a significant source of luminosity degradation in RHIC. The high reliability and flexibility of the new Linac-based pre-injector will lead to increased integrated luminosity at RHIC and is an essential component for the long-term success of the RHIC facility. This new pre-injector, based on an EBIS, also has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium beams and, as part of a future upgrade, might also be used to produce polarized {sup 3}He beams. These capabilities will be critical to the future luminosity upgrades and electron-ion collisions in RHIC. The proposed pre-injector system would also provide for a major enhancement in capability for the NASA Space Radiation Laboratory (NSRL), which utilizes heavy-ion beams from the RHIC complex. EBIS would allow for the acceleration of all important ion species for the NASA radiobiology program, such as, helium, argon, and neon which are unavailable with the present Tandem injector. In addition, the new system would allow for very rapid switching of ion species for NSRL experiments, reducing delays due to the interference with RHIC injection operations, and allowing enhanced mixed field radiation studies. The new RFQ and Linac that are used to accelerate beams from the EBIS to an energy sufficient for injection into the Booster are both very similar to existing devices already in operation at other facilities. Injection into the Booster will occur at the same location as the existing injection from the Tandem.

ALESSI, J.; BARTON, D.; BEEBE, E.; GASSNER, D.; GRANDINETTI, R.; HSEUH, H.; JAVIDFAR, A.; KPONOU, A.; LAMBIASE, R.; LESSARD, E.; LOCKEY, R.; LODESTRO, V.; MAPES, M.; MIRABELLA, D.; NEHRING, T.; OERTER, B.; PENDZICK, A.; PIKIN, A.; RAPARIA, D.; RITTER, J.; ROSER, T.; RUSSO, T.; SNYDSTRUP, L.; WILINSKI, M.; ZALTSMAN, A.; ZHANG, S.

2005-09-01T23:59:59.000Z

136

The uses of electron beam ion traps in the study of highly charged ions  

SciTech Connect (OSTI)

The Electron Beam Ion Trap (EBIT) is a relatively new tool for the study of highly charged ions. Its development has led to a variety of new experimental opportunities; measurements have been performed with EBITs using techniques impossible with conventional ion sources or storage rings. In this paper, I will highlight the various experimental techniques we have developed and the results we have obtained using the EBIT and higher-energy Super-EBIT built at the Lawrence Livermore National Laboratory. The EBIT employs a high-current-density electron beam to trap, ionize, and excite a population of ions. The ions can be studied in situ or extracted from the trap for external experiments. The trapped ions form an ionization-state equilibrium determined by the relative ionization and recombination rates. Ions of several different elements may simultaneously be present in the trap. The ions are nearly at rest, and, for most systems, all in their ground-state configurations. The electron-ion interaction energy has a narrow distribution and can be varied over a wide range. We have used the EBIT devices for the measurement of electron-ion interactions, ion structure, ion-surface interactions, and the behavior of low-density plasmas.

Knapp, D.

1994-11-02T23:59:59.000Z

137

Focused Gaussian Beams for Seismic Imaging Robert L. Nowack*; Dept. of Earth and Atmos. Sci., Purdue University  

E-Print Network [OSTI]

Focused Gaussian Beams for Seismic Imaging Robert L. Nowack*; Dept. of Earth and Atmos. Sci., Purdue University Summary The application of focused Gaussian beams is investigated for the seismic imaging of common-shot reflection data. The focusing of Gaussian beams away from the source and receiver

Nowack, Robert L.

138

Theoretical and Computational Investigation of Periodically Focused Intense Charged-Particle Beams  

SciTech Connect (OSTI)

The purpose of this report is to summarize results of theoretical and computational investigations of periodically focused intense charged-particle beams in parameter regimes relevant to the development of advanced high-brightness, high-power accelerators for high-energy physics research. The breakthroughs and highlights in our research in the period from April 1, 2010 to March 30, 2013 were: a) Theory and simulation of adiabatic thermal Child-Langmuir flow; b) Particle-in-cell simulations of adiabatic thermal beams in periodic solenoidal focusing field; c)Dynamics of charged particles in an adiabatic thermal beam equilibrium in a periodic solenoidal focusing field; d) Training of undergraduate researchers and graduate student in accelerator and beam physics. A brief introduction and summary is presented. Detailed descriptions of research results are provided in an appendix of publications at the end of the report.

Chen, Chiping [Massachusetts Institute of Technology

2013-06-26T23:59:59.000Z

139

Hydrodynamic Efficiency of Ablation Propulsion with Pulsed Ion Beam  

SciTech Connect (OSTI)

This paper presents the hydrodynamic efficiency of ablation plasma produced by pulsed ion beam on the basis of the ion beam-target interaction. We used a one-dimensional hydrodynamic fluid compressible to study the physics involved namely an ablation acceleration behavior and analyzed it as a rocketlike model in order to investigate its hydrodynamic variables for propulsion applications. These variables were estimated by the concept of ablation driven implosion in terms of ablated mass fraction, implosion efficiency, and hydrodynamic energy conversion. Herein, the energy conversion efficiency of 17.5% was achieved. In addition, the results show maximum energy efficiency of the ablation process (ablation efficiency) of 67% meaning the efficiency with which pulsed ion beam energy-ablation plasma conversion. The effects of ion beam energy deposition depth to hydrodynamic efficiency were briefly discussed. Further, an evaluation of propulsive force with high specific impulse of 4000s, total impulse of 34mN and momentum to energy ratio in the range of {mu}N/W was also analyzed.

Buttapeng, Chainarong; Yazawa, Masaru; Harada, Nobuhiro [Department of Electrical Engineering, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka 940-2188 (Japan); Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi [Extreme Energy-Density Research Institute, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka 940-2188 (Japan)

2006-05-02T23:59:59.000Z

140

Risk Management Plan Electron Beam Ion Source Project  

E-Print Network [OSTI]

Risk Management Plan for the Electron Beam Ion Source Project (EBIS) Project # 06-SC-002 at Brookhaven National Laboratory Upton, NY For the U.S. Department of Energy Office of Science Office of Nuclear Physics (SC ­ 26) #12;1. Background and References 1.1 Background The EBIS Project will manage

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Summary II - Fusion Ion sources, Beam Formation, Acceleration and Neutralisation  

SciTech Connect (OSTI)

The 11th International Symposium on the Production and Neutralization of Negative Ions and Beams was held in Santa Fe, New Mexico on 13th - 15th September 2006 and was hosted by Los Alamos National Laboratory. This summary covers the sessions of the Symposium devoted to the topics listed in the title.

Jones, T. T. C. [UKAEA Culham Division, Abingdon, OX14 3DB (United Kingdom)

2007-08-10T23:59:59.000Z

142

Sandia National Laboratories: ion beam assisted deposition  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1developmentturbine blade manufacturing therenewableswind blade inspectionion beam

143

Heavy Ion Beam in Resolution of the Critical Point Problem for Uranium and Uranium Dioxide  

E-Print Network [OSTI]

Important advantages of heavy ion beam (HIB) irradiation of matter are discussed in comparison with traditional sources - laser heating, electron beam, electrical discharge etc. High penetration length (~ 10 mm) is of primary importance for investigation of dense matter properties. This gives an extraordinary chance to reach the uniform heating regime when HIB irradiation is being used for thermophysical property measurements. Advantages of HIB heating of highly-dispersive samples are claimed for providing free and relatively slow quasi-isobaric heating without fast hydrodynamic expansion of heated sample. Perspective of such HIB application are revised for resolution of long-time thermophysical problems for uranium and uranium-bearing compounds (UO2). The priorities in such HIB development are stressed: preferable energy levels, beam-time duration, beam focusing, deposition of the sample etc.

Igor Iosilevskiy; Victor Gryaznov

2010-05-23T23:59:59.000Z

144

Separation of beam and electrons in the spallation neutron source H{sup -} ion source  

SciTech Connect (OSTI)

The Spallation Neutron Source (SNS) requires an ion source producing an H{sup {minus}} beam with a peak current of 35mA at a 6.2 percent duty factor. For the design of this ion source, extracted electrons must be transported and dumped without adversely affecting the H{sup {minus}} beam optics. Two issues are considered: (1) electron containment transport and controlled removal; and (2) first-order H{sup {minus}} beam steering. For electron containment, various magnetic, geometric and electrode biasing configurations are analyzed. A kinetic description for the negative ions and electrons is employed with self-consistent fields obtained from a steady-state solution to Poisson`s equation. Guiding center electron trajectories are used when the gyroradius is sufficiently small. The magnetic fields used to control the transport of the electrons and the asymmetric sheath produced by the gyrating electrons steer the ion beam. Scenarios for correcting this steering by split acceleration and focusing electrodes will be considered in some detail.

Whealton, J.H.; Raridon, R.J. [Oak Ridge National Lab., TN (United States); Leung, K.N. [Lawrence Berkeley National Lab., CA (United States)

1997-12-01T23:59:59.000Z

145

Hydrogen removal from e-beam deposited alumina thin films by oxygen ion beam  

SciTech Connect (OSTI)

Hydrogen interstitials and oxygen vacancies defects create energy levels in the band gap of alumina. This limits the application of alumina as a high-k dielectric. A low thermal budget method for removal of hydrogen from alumina is discussed. It is shown that bombardment of alumina films with low energy oxygen ion beam during electron beam evaporation deposition decreases the hydrogen concentration in the film significantly.

Das, Arijeet, E-mail: arijeet@rrcat.gov.in; Mukharjee, C., E-mail: arijeet@rrcat.gov.in; Rajiv, K., E-mail: arijeet@rrcat.gov.in; Bose, Aniruddha, E-mail: arijeet@rrcat.gov.in; Singh, S. D., E-mail: arijeet@rrcat.gov.in; Rai, S. K.; Ganguli, Tapas; Joshi, S. C.; Deb, S. K. [Raja Ramanna Centre for Advanced Technology, Indore-452013 (India); Phase, D. M. [UGC-DAE Consortium for Scientific Research, Indore-452017 (India)

2014-04-24T23:59:59.000Z

146

Progress in bright ion beams for industry, medicine and fusion at LBNL  

E-Print Network [OSTI]

HI FAN 1160 LBNL-50492 Progress in Bright Ion BeamsMedicine and Fusion at LBNL Joe W. Kwan Lawrence BerkeleyAbstract Recent progresses at LBNL in developing ion beams

Kwan, Joe W.

2002-01-01T23:59:59.000Z

147

E-Print Network 3.0 - accelerated ion beams Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ion beams Search Powered by Explorit Topic List Advanced Search Sample search results for: accelerated ion beams Page: << < 1 2 3 4 5 > >> 1 Siberian Branch of Russian Academy of...

148

Electrostatic dispersion lenses and ion beam dispersion methods  

DOE Patents [OSTI]

An EDL includes a case surface and at least one electrode surface. The EDL is configured to receive through the EDL a plurality of ion beams, to generate an electrostatic field between the one electrode surface and either the case surface or another electrode surface, and to increase the separation between the beams using the field. Other than an optional mid-plane intended to contain trajectories of the beams, the electrode surface or surfaces do not exhibit a plane of symmetry through which any beam received through the EDL must pass. In addition or in the alternative, the one electrode surface and either the case surface or the other electrode surface have geometries configured to shape the field to exhibit a less abrupt entrance and/or exit field transition in comparison to another electrostatic field shaped by two nested, one-quarter section, right cylindrical electrode surfaces with a constant gap width.

Dahl, David A. (Idaho Falls, ID) [Idaho Falls, ID; Appelhans, Anthony D. (Idaho Falls, ID) [Idaho Falls, ID

2010-12-28T23:59:59.000Z

149

Present Status And First Results of the Final Focus Beam Line at the KEK Accelerator Test Facility  

SciTech Connect (OSTI)

ATF2 is a final-focus test beam line which aims to focus the low emittance beam from the ATF damping ring to a vertical size of about 37 nm and to demonstrate nanometer level beam stability. Several advanced beam diagnostics and feedback tools are used. In December 2008, construction and installation were completed and beam commissioning started, supported by an international team of Asian, European, and U.S. scientists. The present status and first results are described.

Bambade, P.; /Orsay /KEK, Tsukuba; Alabau Pons, M.; /Valencia U., IFIC; Amann, J.; /SLAC; Angal-Kalinin, D.; /Daresbury; Apsimon, R.; /Oxford U., JAI; Araki, S.; Aryshev, A.; /KEK, Tsukuba; Bai, S.; /Beijing, Inst. High Energy Phys.; Bellomo, P.; /SLAC; Bett, D.; /Oxford U., JAI; Blair, G.; /Royal Holloway, U. of London; Bolzon, B.; /Savoie U.; Boogert, S.; Boorman, G.; /Royal Holloway, U. of London; Burrows, P.N.; Christian, G.; Coe, P.; Constance, B.; /Oxford U., JAI; Delahaye, Jean-Pierre; /CERN; Deacon, L.; /Royal Holloway, U. of London; Elsen, E.; /DESY /Valencia U., IFIC /KEK, Tsukuba /Beijing, Inst. High Energy Phys. /Savoie U. /Fermilab /Ecole Polytechnique /KEK, Tsukuba /Kyungpook Natl. U. /KEK, Tsukuba /Pohang Accelerator Lab. /Kyoto U., Inst. Chem. Res. /Savoie U. /Daresbury /Tokyo U. /Royal Holloway, U. of London /Kyungpook Natl. U. /Pohang Accelerator Lab. /Tokyo U. /KEK, Tsukuba /SLAC /University Coll. London /KEK, Tsukuba /SLAC /Royal Holloway, U. of London /KEK, Tsukuba /Tokyo U. /SLAC /Tohoku U. /KEK, Tsukuba /Tokyo U. /Pohang Accelerator Lab. /Brookhaven /SLAC /Oxford U., JAI /SLAC /Orsay /KEK, Tsukuba /Oxford U., JAI /Orsay /Fermilab /Tohoku U. /Manchester U. /CERN /SLAC /Tokyo U. /KEK, Tsukuba /Oxford U., JAI /Hiroshima U. /KEK, Tsukuba /CERN /KEK, Tsukuba /Oxford U., JAI /Ecole Polytechnique /SLAC /Oxford U., JAI /Fermilab /SLAC /Liverpool U. /SLAC /Tokyo U. /SLAC /Tokyo U. /KEK, Tsukuba /SLAC /CERN

2011-11-11T23:59:59.000Z

150

Method for measuring and controlling beam current in ion beam processing  

DOE Patents [OSTI]

A method for producing film thickness control of ion beam sputter deposition films. Great improvements in film thickness control is accomplished by keeping the total current supplied to both the beam and suppressor grids of a radio frequency (RF) in beam source constant, rather than just the current supplied to the beam grid. By controlling both currents, using this method, deposition rates are more stable, and this allows the deposition of layers with extremely well controlled thicknesses to about 0.1%. The method is carried out by calculating deposition rates based on the total of the suppressor and beam currents and maintaining the total current constant by adjusting RF power which gives more consistent values.

Kearney, Patrick A. (Livermore, CA); Burkhart, Scott C. (Livermore, CA)

2003-04-29T23:59:59.000Z

151

The production of dense lead-ion beams for the CERN LHC  

E-Print Network [OSTI]

To reach the design luminosity for lead-ions in the LHC, the present Low Energy Antiproton Ring (LEAR) has to be converted into a Low Energy Ion Ring (LEIR). Since the present ECR lead-ion source does not provide sufficient intensity, the main goal of LEIR is to act as a low-energy (4.2MeV/u) accumulator where the ion beam is stacked and cooled (with the help of an electron-cooler) to reach the required intensity and emittances. An experimental program has been carried out at LEAR in recent years in order to test the cooling and stacking process with the present electron-cooler. A variety of results have been reported at previous conferences. This paper will focus on the electron cooling aspects resulting from the afore mentioned experiments. Taking into account the experience

Bosser, Jacques; Chanel, M; MacCaferri, R; Molinari, G; Maury, S; Möhl, D; Tranquille, G

2000-01-01T23:59:59.000Z

152

Dynamics of Ion Beam Stimulated Surface Mass Transport to Nanopores David P. Hoogerheide1  

E-Print Network [OSTI]

Dynamics of Ion Beam Stimulated Surface Mass Transport to Nanopores David P. Hoogerheide1 membrane, from the substrate side, by rastering a 10-nm diameter, 50 keV gallium ion beam produced by a FEI We explore the ion beam-induced dynamics of the formation of large features at the edges of nanopores

153

Stimulated Raman Scattering and Nonlinear Focusing of High-Power Laser Beams Propagating in Water  

E-Print Network [OSTI]

The physical processes associated with propagation of a high-power (power > critical power for self-focusing) laser beam in water include nonlinear focusing, stimulated Raman scattering (SRS), optical breakdown and plasma formation. The interplay between nonlinear focusing and SRS is analyzed for cases where a significant portion of the pump power is channeled into the Stokes wave. Propagation simulations and an analytical model demonstrate that the Stokes wave can re-focus the pump wave after the power in the latter falls below the critical power. It is shown that this novel focusing mechanism is distinct from cross-phase focusing. While discussed here in the context of propagation in water, the gain-focusing phenomenon is general to any medium supporting nonlinear focusing and stimulated forward Raman scattering.

Hafizi, B; Penano, J R; Gordon, D F; Jones, T G; Helle, M H; Kaganovich, D

2015-01-01T23:59:59.000Z

154

Applied Physics B28, 2/3 239 cw Ion Lasers Pumpedby Electron Beams  

E-Print Network [OSTI]

Applied Physics B28, 2/3 239 cw Ion Lasers Pumpedby Electron Beams J. J. Rocca, J. D. Meyer, Zeng, and As by exciting He metal-vapor mixtures with a dc electron beam. The beam is generated by glow discharge electron obtained using electron beam excitation. The conventional manner of exciting cw ion lasers is to use

Rocca, Jorge J.

155

The Scientific program with RIBRAS (Radioactive Ion Beams in Brasil)  

SciTech Connect (OSTI)

The Radioactive Ion Beams Facility (RIBRAS) is in operation since 2004 at the Pelletron Accelerator Laboratory of the University of Sao Paulo and consists of two superconducting solenoids capable of producing low energy secondary beams of light exotic nuclei. Measurements of the elastic scattering, breakup and transfer reactions with radioactive projectiles such as {sup 6}He,{sup 8}Li,{sup 7}Be on several targets have been performed. A review of the research program carried on along the last four years using the RIBRAS facility is presented.

Lichtenthaeler, R.; Lepine-Szily, A.; Guimaraes, V.; Faria, P. N. de; Mendes, D. R. Jr.; Pires, K. C. C.; Morcelle, V.; Hussein, M. S.; Barioni, A.; Condori, R. Pampa; Morais, M. C.; Alcantara Nunez, J.; Camargo, O. Jr.; Otani, Y.; Leistenschneider, E.; Scarduelli, V. [Instituto de Fisica da Universidade de Sao Paulo, C.P. 66318, 05389-970 Sao Paulo (Brazil); Benjamim, E. A. [Universidad de Santiago de Compostela, Depto. Fisica Particulas, Facultad Fisica, Campus Sur s/n 15786 Santiago de Compostela (Spain) (Spain); Moro, A. M. [Departamento de FAMN, Universidad de Sevilla, Apdo 1065, E-41080, Sevilla (Spain); Arazi, A. [Laboratorio Tandar, Departamento de Fisica, Comision Nacional de Energia Atomica, Av. del Libertador 8250, (1429), Buenos Aires (Argentina); Assuncao, M. [UNIFESP-Campus de Diadema, SP (Brazil)] (and others)

2009-06-03T23:59:59.000Z

156

Proton Beam Lithography at the University of Surrey's Ion Beam Centre , I. Gomez-Morilla  

E-Print Network [OSTI]

the Ion Scan software developed by the National University of Singapore [4]. Simulations with the SRIM in photosensitive glass [3]. This technique has clear advantages in comparison with electron beam lithography and X energy protons have a long range and a low lateral spread making them ideal for exposing thick resist

Webb, Roger P.

157

Ponderomotive self-focusing of Gaussian laser beam in warm collisional plasma  

SciTech Connect (OSTI)

The propagation characteristics of a Gaussian laser beam through warm collisional plasma are investigated by considering the ponderomotive force nonlinearity and the complex eikonal function. By introducing the dielectric permittivity of warm unmagnetized plasma and using the WKB and paraxial ray approximations, the coupled differential equations defining the variations of laser beam parameters are obtained and solved numerically. Effects of laser and plasma parameters such as the collision frequency, the initial laser intensity and its spot size on the beam width parameter and the axis laser intensity distribution are analyzed. It is shown that, self-focusing of the laser beam takes place faster by increasing the collision frequency and initial laser spot size and then after some distance propagation the laser beam abruptly loses its initial diameter and vastly diverges. Furthermore, the modified electron density distribution is obtained and the collision frequency effect on this distribution is studied.

Jafari Milani, M. R., E-mail: mrj.milani@gmail.com [Plasma Physics Research School, Tehran (Iran, Islamic Republic of); Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Niknam, A. R., E-mail: a-niknam@sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of); Farahbod, A. H. [Plasma Physics Research School, Tehran (Iran, Islamic Republic of)

2014-06-15T23:59:59.000Z

158

Heavy ion beam loss mechanisms at an electron-ion collider  

E-Print Network [OSTI]

There are currently several proposals to build a high-luminosity electron-ion collider, to study the spin structure of matter and measure parton densities in heavy nuclei, and to search for gluon saturation and new phenomena like the colored glass condensate. These measurements require operation with heavy-nuclei. We calculate the cross-sections for two important processes that will affect accelerator and detector operations: bound-free pair production, and Coulomb excitation of the nuclei. Both of these reactions have large cross-sections, 28-56 mb, which can lead to beam ion losses, produce beams of particles with altered charge:mass ratio, and produce a large flux of neutrons in zero degree calorimeters. The loss of beam particles limits the sustainable electron-ion luminosity to levels of several times $10^{32}/$cm$^2$/s.

Spencer R. Klein

2014-09-18T23:59:59.000Z

159

A focusable, convergent fast-electron beam from ultra-high-intensity laser-solid interactions  

E-Print Network [OSTI]

A novel scheme for the creation of a convergent, or focussing, fast-electron beam generated from ultra-high-intensity laser-solid interactions is described. Self-consistent particle-in-cell simulations are used to demonstrate the efficacy of this scheme in two dimensions. It is shown that a beam of fast-electrons of energy 500 keV - 3 MeV propagates within a solid-density plasma, focussing at depth. The depth of focus of the fast-electron beam is controlled via the target dimensions and focussing optics.

Scott, R H H

2015-01-01T23:59:59.000Z

160

Beam Loss Ion Chamber System Upgrade for Experimental Halls  

SciTech Connect (OSTI)

The Beam loss Ion Chamber System (BLICS) was developed to protect Jefferson Labs transport lines, targets and beam dumps from a catastrophic ''burn through''. Range changes and testing was accomplished manually requiring the experiment to be shut down. The new upgraded system is based around an ''off the shelf'' Programmable Logic Controller located in a single control box supporting up to ten individual detectors. All functions that formerly required an entry into the experimental hall and manual adjustment can be accomplished from the Machine Control Center (MCC). A further innovation was the addition of a High Voltage ''Brick'' at the detector location. A single cable supplies the required voltage for the Brick and a return line for the ion chamber signal. The read back screens display range, trip point, and accumulated dose for each location. The new system is very cost effective and significantly reduces the amount of lost experimental time.

D.W. Dotson; D.J. Seidman

2005-05-16T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Planarization of amorphous carbon films on patterned substrates using gas cluster ion beams  

SciTech Connect (OSTI)

Surface planarization and modification of a patterned surface were demonstrated using gas cluster ion beam (GCIB). Grooves with 100-400 nm intervals were formed on amorphous carbon films using focused ion beams to study the special frequency dependence of the planarization. Also, line and space patterns were fabricated on Si substrates, and amorphous carbons were deposited as a model structure of discrete track media. Subsequently, surface planarization using Ar-GCIB was carried out. After GCIB irradiations, all of the grooves were completely removed, and a flat surface was realized. And it showed that GCIB irradiation planarized grooves without huge thickness loss. From the power spectrum density of an atomic force microscope, GCIB preferentially removed grooves with small intervals. It was found from energy dispersive x-ray spectroscopy that surface planarization without severe damage in the amorphous carbon and magnetic layers was carried out with GCIB.

Toyoda, Noriaki; Yamada, Isao [Incubation Center, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan); Nagato, Keisuke; Nakao, Masayuki; Hamaguchi, Tetsuya [Department of Engineering Synthesis, School of Engineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Tani, Hiroshi [Department of Mechanical Engineering, Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680 (Japan); Sakane, Yasuo [Western Digital Media Operations, 1710 Automation Parkway, San Jose, CA 95131 (United States)

2009-04-01T23:59:59.000Z

162

Design and Fabrication of the Lithium Beam Ion Injector for NDCX-II  

SciTech Connect (OSTI)

A 130 keV injector is developed for the NDCX-II facility. It consists of a 10.9 cm diameter lithium doped alumina-silicate ion source heated to {approx}1300 C and 3 electrodes. Other components include a segmented Rogowski coil for current and beam position monitoring, a gate valve, pumping ports, a focusing solenoid, a steering coil and space for inspection and maintenance access. Significant design challenges including managing the 3-4 kW of power dissipation from the source heater, temperature uniformity across the emitter surface, quick access for frequent ion source replacement, mechanical alignment with tight tolerance, and structural stabilization of the cantilevered 27-inch OD graded HV ceramic column. The injector fabrication is scheduled to complete by May 2011, and assembly and installation is scheduled to complete by the beginning of July. The Neutralized Drift Compression eXperiment (NDCX-II) is for the study of high energy density physics and inertial fusion energy research utilizing a lithium ion (Li+) beam with a current of 93 mA and a pulse length of 500 ns (compressed to 1 ns at the target). The injector is one of the most complicated sections of the NDCX-II accelerator demanding significant design and fabrication resources. It needs to accommodate a relatively large ion source (10.9 cm), a high heat load (3-4 kW) and specific beam optics developed from the physics model. Some specific design challenges are noted in this paper.

Takakuwa, J.

2011-03-01T23:59:59.000Z

163

Negative Ion Based Heating and Diagnostic Neutral Beams for ITER  

SciTech Connect (OSTI)

To meet the requirements of the four operating and one start-up scenarios foreseen in the International Tokamak Experimental Reactor (ITER) a flexible heating mix will be required, which has to include a reliable contribution from neutral beams. The current baseline of ITER foresees 2 Heating Neutral Beam (HNB) systems based on negative ion technology, each operating at 1 MeV 40 A D{sup -} ions, and each capable of delivering up to 16.7 MW of D deg. to the ITER plasma. A 3rd HNB injector is foreseen as an upgrade option. In addition a dedicated Diagnostic Neutral Beam (DNB) injecting 100 keV 60 A of negative hydrogen ions will be available for charge exchange resonant spectroscopy (CXRS). The significant R and D effort necessary to meet the design requirements will be provided in the Neutral Beam Test Facility (NBTF), which is to be constructed in Padua, Italy. This paper gives an overview of the current status of the neutral beam (NB) systems and the chosen configuration. The ongoing integration effort into the ITER plant is highlighted and open interface issues are identified. It is shown how installation and maintenance logistics has influenced the design. ITER operating scenarios are briefly discussed, including start-up and commissioning. For example it is now envisaged to have a low current hydrogen phase of ITER operations, essentially for commissioning of the many auxiliary systems used on ITER. The low current limits the achievable plasma density, and hence the NB energy due to shine through limitations. Therefore a possible reconfiguration of the auxiliary heating systems is now being discussed. Other NB related issues identified by the ongoing design review process are emphasized and possible impact on the implementations of the HNB and DNB systems is indicated.

Schunke, B.; Bora, D.; Cordier, J.-J.; Hemsworth, R.; Tanga, A. [ITER Organization, Cadarache, 13108 St.-Paul-lez-Durance (France); Antoni, V. [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti 4, I-35127 (Italy); Bonicelli, T. [IPR, Bhat, Gandhinagar, Gujarat, 382428 (India); Chakraborty, A. [EFDA CSU, Boltzmannstrasse 2, D-85748, Garching (Germany); Inoue, T.; Watanabe, K. [JAEA, 801-1 Mukouyama, Naka-machi, Naka-gun, Ibaraki-ken 311-0193 (Japan)

2008-04-07T23:59:59.000Z

164

Control system for the Holifield Radioactive Ion Beam Facility  

SciTech Connect (OSTI)

A new accelerator control system is being implemented as part of the development of the Holifield Radioactive Ion Beam Facility (HRIBF), a first generation radioactive ion beam (RIB) facility. The pre- existing accelerator control systems are based on 1970`s technology and addition or alteration of controls is cumbersome and costly. A new, unified control system for the cyclotron and tandem accelerators, the RIB injector, ion sources, and accelerator beam lines is based on a commercial product from Vista Control Systems, Inc. Several other accelerator facilities, as well as numerous industrial sites, are now using this system. The control system is distributed over a number of computers which communicate over Ethernet and is easily extensible. Presently, implementation at the HRIBF is based on VAX/VMS, VAX/ELN, VME, and Allen-Bradley PLC5 programmable logic controller architectures. Expansion to include UNIX platforms and CAMAC hardware support is planned. Operator interface is via X- terminals. The system has proven to be quite powerful, yet is has been easy to implement with a small staff. A Vista users group has resulted in shared software to implement specific controls. This paper details present system features and future implementations at the HRIBF.

Tatum, B.A.; Juras, R.C.; Meigs, M.J.

1995-12-31T23:59:59.000Z

165

Nanostructured ion beam-modified Ge films for high capacity Li ion battery anodes  

SciTech Connect (OSTI)

Nanostructured ion beam-modified Ge electrodes fabricated directly on Ni current collector substrates were found to exhibit excellent specific capacities during electrochemical cycling in half-cell configuration with Li metal for a wide range of cycling rates. Structural characterization revealed that the nanostructured electrodes lose porosity during cycling but maintain excellent electrical contact with the metallic current collector substrate. These results suggest that nanostructured Ge electrodes have great promise for use as high performance Li ion battery anodes.

Rudawski, N. G.; Darby, B. L.; Yates, B. R.; Jones, K. S. [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611-6400 (United States); Elliman, R. G. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 0200 (Australia); Volinsky, A. A. [Department of Mechanical Engineering, University of South Florida, Tampa Florida 33620 (United States)

2012-02-20T23:59:59.000Z

166

Space Charge Compensation in the Linac4 Low Energy Beam Transport Line with Negative Hydrogen Ions  

E-Print Network [OSTI]

The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Tranport (LEBT) using the package IBSimu1, which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H- beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

Valerio-Lizarraga, C; Leon-Monzon, I; Lettry, J; Midttun, O; Scrivens, R

2013-01-01T23:59:59.000Z

167

Infrared measurements and simulations of metal meshes in a focused beam  

SciTech Connect (OSTI)

Infrared transmittance measurements of quasioptical filters are often restricted to a focused beam due to the optical design of the spectrometer. In contrast, numerical simulations assume an incident plane wave, which makes it difficult to compare theory with experimental data. We compare transmittance measurements with numerical simulations of square arrays of circular holes in 3-?m thick Cu sheets at angles of incidence from 0° to 20° for both s and p polarizations. These simple structures allow detailed tests of our electromagnetic simulation methods and show excellent agreement between theory and measurement. Measurements in a focused beam are accurately simulated by combining plane wave calculations over a range of angles that correspond to the focal ratio of the incident beam. Similar screens have been used as components of narrow bandpass filters for far-infrared astronomy, but these results show that the transmittance variations with angle of incidence and polarization limit their use to collimated beams at near normal incidence. The simulations are accurate enough to eliminate a costly trial-and-error approach to the design of more complex and useful quasioptical infrared filters and to predict their in-band performance and out-of-band blocking in focused beams.

Stewart, K. P., E-mail: ken.stewart@nrl.navy.mil [Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Möller, K. D.; Grebel, H. [Electrical Engineering Department, New Jersey Institute of Technology, Electronic Imaging Center, Newark, New Jersey 07102 (United States)

2014-02-07T23:59:59.000Z

168

The energy transfer in the TEMP-4M pulsed ion beam accelerator  

SciTech Connect (OSTI)

The results of a study of the energy transfer in the TEMP-4M pulsed ion beam accelerator are presented. The energy transfer efficiency in the Blumlein and a self-magnetically insulated ion diode was analyzed. Optimization of the design of the accelerator allows for 85% of energy transferred from Blumlein to the diode (including after-pulses), which indicates that the energy loss in Blumlein and spark gaps is insignificant and not exceeds 10%–12%. Most losses occur in the diode. The efficiency of energy supplied to the diode to the energy of accelerated ions is 8%–9% for a planar strip self-magnetic MID, 12%–15% for focusing diode and 20% for a spiral self-magnetic MID.

Isakova, Y. I.; Pushkarev, A. I.; Khaylov, I. P. [Tomsk Polytechnic University, 30 Lenin Ave., Tomsk 634050 (Russian Federation)] [Tomsk Polytechnic University, 30 Lenin Ave., Tomsk 634050 (Russian Federation)

2013-07-15T23:59:59.000Z

169

Interface and process for enhanced transmission of non-circular ion beams between stages at unequal pressure  

DOE Patents [OSTI]

The invention discloses a new interface with non-circular conductance limit aperture(s) useful for effective transmission of non-circular ion beams between stages with different gas pressure. In particular, the invention provides an improved coupling of field asymmetric waveform ion mobility spectrometry (FAIMS) analyzers of planar or side-to-side geometry to downstream stages such as mass spectrometry or ion mobility spectrometry. In this case, the non-circular aperture is rectangular; other geometries may be optimum in other applications. In the preferred embodiment, the non-circular aperture interface is followed by an electrodynamic ion funnel that may focus wide ion beams of any shape into tight circular beams with virtually no losses. The jet disrupter element of the funnel may also have a non-circular geometry, matching the shape of arriving ion beam. The improved sensitivity of planar FAIMS/MS has been demonstrated in experiments using a non-contiguous elongated aperture but other embodiments (e.g., with a contiguous slit aperture) may be preferable, especially in conjunction with an ion funnel operated at high pressures.

Tang, Keqi (Richland, WA); Shvartsburg, Alexandre A. (Richland, WA); Smith, Richard D. (Richland, WA)

2008-03-04T23:59:59.000Z

170

Development and Application of an Electrospray Ionization Ion Mobility-mass Spectrometer Using an RF Ion Funnel and Periodic-focusing Ion Guide  

E-Print Network [OSTI]

home-built electrospray ionization (ESI) source and rf ion funnel(IF) as an ion transfer interface, modular periodic-focusing ion guide (PFIG) as a drift tube (DT) for arrival time measurement, and orthogonally accelerated linear time-of-flight mass...

Jeon, Junho

2013-10-16T23:59:59.000Z

171

Nuclear Spectroscopy Using Radioactive Ion Beams from the HRIBF  

SciTech Connect (OSTI)

Exciting opportunities in the study of nuclei far from stability in both the neutron and proton rich side are opening with the recent availability of radioactive ion beams (RIBs) at energies above the Coulomb barrier at the Holifield Radioactive Ion Beam Facility (HRIBF). These RIBs provide a unique opportunity for a whole class of measurements that could never before be realized. A recent highlight has been the acceleration of 'pure' beams of fission fragments such as 82Ge (T1/2=4.6s) and 132Sn (T1/2=40s). These semi-magic and doubly-magic nuclei are important benchmarks within the chart of nuclides, because they are constraints for the shell-model parameter sets. We are currently developing the required experimental tools and specialized techniques for studies in nuclear astrophysics, reaction spectroscopy, and nuclear structure research with RIBs. I will discuss some of the challenges encountered with examples from selected topical areas with which I have been involved.

Galindo-Uribarri, A. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

2004-02-27T23:59:59.000Z

172

Nuclear Spectroscopy Using Radioactive Ion Beams from the HRIBF  

SciTech Connect (OSTI)

Exciting opportunities in the study of nuclei far from stability in both the neutron and proton rich side are opening with the recent availability of radioactive ion beams (RIBs) at energies above the Coulomb barrier at the Holifield Radioactive Ion Beam Facility (HRIBF). These RIBs provide a unique opportunity for a whole class of measurements that could never before be realized. A recent highlight has been the acceleration of 'pure' beams of fission fragments such as 82Ge (T1/2=4.6s) and 132Sn (T1/2=40s). These semi-magic and doubly-magic nuclei are important benchmarks within the chart of nuclides, because they are constraints for the shell-model parameter sets. We are currently developing the required experimental tools and specialized techniques for studies in nuclear astrophysics, reaction spectroscopy, and nuclear structure research with RIBs. I will discuss some of the challenges encountered with examples from selected topical areas with which I have been involved.

Galindo-Uribarri, Alfredo {nmn} [ORNL

2004-01-01T23:59:59.000Z

173

Three dimensional simulations of space charge dominated heavy ion beams with applications to inertial fusion energy  

SciTech Connect (OSTI)

Heavy ion fusion requires injection, transport and acceleration of high current beams. Detailed simulation of such beams requires fully self-consistent space charge fields and three dimensions. WARP3D, developed for this purpose, is a particle-in-cell plasma simulation code optimized to work within the framework of an accelerator`s lattice of accelerating, focusing, and bending elements. The code has been used to study several test problems and for simulations and design of experiments. Two applications are drift compression experiments on the MBE-4 facility at LBL and design of the electrostatic quadrupole injector for the proposed ILSE facility. With aggressive drift compression on MBE-4, anomalous emittance growth was observed. Simulations carried out to examine possible causes showed that essentially all the emittance growth is result of external forces on the beam and not of internal beam space-charge fields. Dominant external forces are the dodecapole component of focusing fields, the image forces on the surrounding pipe and conductors, and the octopole fields that result from the structure of the quadrupole focusing elements. Goal of the design of the electrostatic quadrupole injector is to produce a beam of as low emittance as possible. The simulations show that the dominant effects that increase the emittance are the nonlinear octopole fields and the energy effect (fields in the axial direction that are off-axis). Injectors were designed that minimized the beam envelope in order to reduce the effect of the nonlinear fields. Alterations to the quadrupole structure that reduce the nonlinear fields further were examined. Comparisons were done with a scaled experiment resulted in very good agreement.

Grote, D.P.

1994-11-01T23:59:59.000Z

174

Origin and control of magnetic exchange coupling in between focused electron beam deposited cobalt nanostructures  

SciTech Connect (OSTI)

We demonstrate the existence and control of inter-particle magnetic exchange coupling in densely packed nanostructures fabricated by focused electron beam induced deposition. With Xe beam post-processing, we have achieved the controlled reduction and eventual elimination of the parasitic halo-like cobalt deposits formed in the proximity of intended nanostructures, which are the identified source of the magnetic exchange coupling. The elimination of the halo-mediated exchange coupling is demonstrated by magnetic measurements using Kerr microscopy on Co pillar arrays. Electron microscopy studies allowed us to identify the mechanisms underlying this process and to verify the efficiency and opportunities of the described nano-scale fabrication approach.

Nikulina, E.; Idigoras, O.; Porro, J. M.; Berger, A. [CIC nanoGUNE Consolider, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian (Spain)] [CIC nanoGUNE Consolider, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian (Spain); Vavassori, P.; Chuvilin, A. [CIC nanoGUNE Consolider, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian (Spain) [CIC nanoGUNE Consolider, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian (Spain); Ikerbasque, Basque Foundation for Science, Alameda Urquijo 36-5, 48011 Bilbao (Spain)

2013-09-16T23:59:59.000Z

175

Production of intense negative hydrogen beams with polarized nuclei by selective neutralization of cold negative ions  

DOE Patents [OSTI]

A process for selectively neutralizing H/sup -/ ions in a magnetic field to produce an intense negative hydrogen ion beam with spin polarized protons. Characteristic features of the process include providing a multi-ampere beam of H/sup -/ ions that are

Hershcovitch, A.

1984-02-13T23:59:59.000Z

176

High energy heavy ion jets emerging from laser plasma generated by long pulse laser beams from  

E-Print Network [OSTI]

, Albuquerque, New Mexico. ~Received 21 February 2005; Accepted 20 April 2005! Abstract High energy heavy ions to the fast ion emission process. The interest in laser plasmas and interaction phenomena of heavy ion beams!. Thus there is a tradition to investigate accelerator related issues like beam transport phenomena

177

Generation and focusing of electron beams with initial transverse-longitudinal correlation  

SciTech Connect (OSTI)

In charged particle beams, one of the roles played by space charge is to couple the transverse and longitudinal dynamics of the beam. This can lead to very complex phenomena which are generally studied using computer simulations. However, in some cases models based on phenomenological or analytic approximations can provide valuable insight into the system behavior. In this paper, we employ such approximations to investigate the conditions under which all the slices of a space charge dominated electron beam with slowly varying current could be focused to a waist with the same radius and at the same location, independent of slice current, and show that this can be accomplished approximately if the initial transverse-longitudinal correlation introduced onto the beam by the electron gun is chosen to compensate for the transverse-longitudinal correlation introduced onto the beam in the drift section. The validity of our approximations is assessed by use of progressively more realistic calculations. We also consider several design elements of electron guns that affect the initial correlations in the beams they generate.

Harris, J. R., E-mail: john.harris@colostate.edu [Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States); Lewellen, J. W. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Poole, B. R. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2014-10-07T23:59:59.000Z

178

Energy spectrum of argon ions emitted from Filippov type Sahand plasma focus  

SciTech Connect (OSTI)

The energy and flux of the argon ions produced in Sahand plasma focus have been measured by employing a well-designed Faraday cup. The secondary electron emission effects on the ion signals are simulated and the dimensions of Faraday cup are optimized to minimize these effects. The measured ion energy spectrum is corrected for the ion energy loss and charge exchange in the background gas. The effects of the capacitor bank voltage and working gas pressure on the ion energy spectrum are also investigated. It has been shown that the emitted ion number per energy increases as the capacitor bank voltage increases. Decreasing the working gas pressure leads to the increase in the number of emitted ion per energy.

Mohammadnejad, M.; Pestehe, S. J.; Mohammadi, M. A. [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Postal Code 5166614766, Tabriz (Iran, Islamic Republic of) [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Postal Code 5166614766, Tabriz (Iran, Islamic Republic of); Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz (Iran, Islamic Republic of)

2013-07-15T23:59:59.000Z

179

Method and means of directing an ion beam onto an insulating surface for ion implantation or sputtering  

DOE Patents [OSTI]

A beam of ions is directed under control onto an insulating surface by supplying simultaneously a stream of electrons directed at the same surface in a quantity sufficient to neutralize the overall electric charge of the ion beam and result in a net zero current flow to the insulating surface. The ion beam is adapted particularly both to the implantation of ions in a uniform areal disposition over the insulating surface and to the sputtering of atoms or molecules of the insulator onto a substrate.

Gruen, Dieter M. (Downers Grove, IL); Krauss, Alan R. (Naperville, IL); Siskind, Barry (Downers Grove, IL)

1981-01-01T23:59:59.000Z

180

Control of domain wall pinning by localised focused Ga?{sup +} ion irradiation on Au capped NiFe nanowires  

SciTech Connect (OSTI)

Understanding domain wall pinning and propagation in nanowires are important for future spintronics and nanoparticle manipulation technologies. Here, the effects of microscopic local modification of the magnetic properties, induced by focused-ion-beam intermixing, in NiFe/Au bilayer nanowires on the pinning behavior of domain walls was investigated. The effects of irradiation dose and the length of the irradiated features were investigated experimentally. The results are considered in the context of detailed quasi-static micromagnetic simulations, where the ion-induced modification was represented as a local reduction of the saturation magnetization. Simulations show that domain wall pinning behavior depends on the magnitude of the magnetization change, the length of the modified region, and the domain wall structure. Comparative analysis indicates that reduced saturation magnetisation is not solely responsible for the experimentally observed pinning behavior.

Burn, D. M., E-mail: d.burn@imperial.ac.uk; Atkinson, D. [Department of Physics, Durham University, Durham (United Kingdom)

2014-10-28T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
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to obtain the most current and comprehensive results.


181

E-Print Network 3.0 - alkali ion beams Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

beams Search Powered by Explorit Topic List Advanced Search Sample search results for: alkali ion beams Page: << < 1 2 3 4 5 > >> 1 METHOD FOR EFFICIENCY AND TIME RESPONSE...

182

Helicon plasma generator-assisted surface conversion ion source for the production of H{sup -} ion beams at the Los Alamos Neutron Science Center  

SciTech Connect (OSTI)

The converter-type negative ion source currently employed at the Los Alamos Neutron Science Center (LANSCE) is based on cesium enhanced surface production of H{sup -} ion beams in a filament-driven discharge. In this kind of an ion source the extracted H{sup -} beam current is limited by the achievable plasma density which depends primarily on the electron emission current from the filaments. The emission current can be increased by increasing the filament temperature but, unfortunately, this leads not only to shorter filament lifetime but also to an increase in metal evaporation from the filament, which deposits on the H{sup -} converter surface and degrades its performance. Therefore, we have started an ion source development project focused on replacing these thermionic cathodes (filaments) of the converter source by a helicon plasma generator capable of producing high-density hydrogen plasmas with low electron energy. In our studies which have so far shown that the plasma density of the surface conversion source can be increased significantly by exciting a helicon wave in the plasma, and we expect to improve the performance of the surface converter H{sup -} ion source in terms of beam brightness and time between services. The design of this new source and preliminary results are presented, along with a discussion of physical processes relevant for H{sup -} ion beam production with this novel design. Ultimately, we perceive this approach as an interim step towards our long-term goal, combining a helicon plasma generator with an SNS-type main discharge chamber, which will allow us to individually optimize the plasma properties of the plasma cathode (helicon) and H{sup -} production (main discharge) in order to further improve the brightness of extracted H{sup -} ion beams.

Tarvainen, O.; Rouleau, G.; Keller, R.; Geros, E.; Stelzer, J.; Ferris, J. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2008-02-15T23:59:59.000Z

183

Opportunistic Mass Measurements at the Holifield Radioactive Ion Beam Facility  

SciTech Connect (OSTI)

A technique for measuring mass differences has been developed at the Holifield Radioactive Ion Beam Facility (HRIBF) that requires no specialized equipment. Mass differences are measured as position differences between known and unknown-mass isobars, dispersed at the image of the energy-analyzing magnet following the 25MV tandem post-accelerator, and identified by an energy-loss measurement. The technique has been demonstrated on neutron-rich 77 79Cu and 83 86Ge isotopes produced using the isotope separator online (ISOL) method with the 238U(p,fission) reaction, where a mass accuracy of 500 keV was achieved. These nuclides are well suited to the measurement technique, as they readily migrate out of the production target and to the ion source and comprise the most neutron-rich elements of the isobarically mixed beam. Because modest precision mass values can be obtained with only a few tens of counts of the nuclide of interest among orders of magnitude more of the isobaric neighbors closer to stability, the sensitivity of this technique makes it appropriate for initial mass measurements far from stability.

Hausladen, Paul [ORNL; Beene, James R [ORNL; Galindo-Uribarri, Alfredo {nmn} [ORNL; Larochelle, Y [University of Tennessee, Knoxville (UTK); Liang, J Felix [ORNL; Mueller, Paul Edward [ORNL; Shapira, Dan [ORNL; Stracener, Daniel W [ORNL; Thomas, J. S. [Rutgers University; Varner Jr, Robert L [ORNL; Wollnik, Hermann [ORNL

2006-01-01T23:59:59.000Z

184

E-Print Network 3.0 - ar ion beam Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

University Collection: Materials Science 3 OPERATION STATUS OF HIGH INTENSITY ION BEAMS AT GANIL F. Chautard, G. Sncal, GANIL, Caen, France Summary: OPERATION STATUS OF HIGH...

185

Determination of ion track radii in amorphous matrices via formation of nano-clusters by ion-beam irradiation  

SciTech Connect (OSTI)

We report on a method for the determination of ion track radii, formed in amorphous materials by ion-beam irradiation. The method is based on the addition to an amorphous matrix of a small amount of foreign atoms, which easily diffuse and form clusters when the temperature is sufficiently increased. The irradiation causes clustering of these atoms, and the final separations of the formed clusters are dependent on the parameters of the ion-beam. Comparison of the separations between the clusters that are formed by ions with different properties in the same type of material enables the determination of ion-track radii.

Buljan, M.; Karlusic, M.; Bogdanovic-Radovic, I.; Jaksic, M.; Radic, N. [Rudjer Boskovic Institute, Bijenicka cesta 54, 10000 Zagreb (Croatia); Salamon, K. [Institute of Physics, 10000 Zagreb (Croatia); Bernstorff, S. [Sincrotrone Trieste, 34102 Basovizza (Italy)

2012-09-03T23:59:59.000Z

186

Heating of beam ions by ion acoustic waves A. Vaivads, K. Ro nnmark, T. Oscarsson, and M. Andre  

E-Print Network [OSTI]

spectral density at frequencies much below the ion gyrofrequency. The wave power decreases with increasingHeating of beam ions by ion acoustic waves A. Vaivads, K. RoÃ? nnmark, T. Oscarsson, and M. AndreÃ? Swedish Institute of Space Physics, University of UmeaÃ? , S-901 87 UMEAÃ? , Sweden Received: 30 April 1997

Paris-Sud XI, Université de

187

Overview of the current spectroscopy effort on the Livermore electron beam ion traps  

SciTech Connect (OSTI)

An overview is given of the current spectroscopic effort on the Livermore electron beam ion trap facilities. The effort focuses on four aspects: spectral line position, line intensity, temporal evolution, and line shape. Examples of line position measurements include studies of the K-shell transitions in heliumlike Kr{sup 34+} and the 2s-2p intrashell transitions in lithiumlike Th{sup 87+} and U{sup 89+}, which provide benchmark values for testing the theory of relativistic and quantum electrodynamical contributions in high-Z ions. Examples of line intensity measurements are provided by measurements of the electron-impact excitation and dielectronic recombination cross sections of heliumlike transition-metal ions Ti{sup 20+} through CO{sup 25+}. A discussion of radiative lifetime measurements of metastable levels in heliumlike ions is given to illustrate the time-resolved spectroscopy techniques in the microsecond range. The authors also present a measurement of the spectral lineshape that illustrates the very low ion temperatures that can be achieved in an EBIT.

Beiersdorfer, P.; Lopez-Urrutia, J.C. [Lawrence Livermore National Lab., CA (United States); Brown, G. [Auburn Univ., AL (United States)] [and others

1995-06-29T23:59:59.000Z

188

Experimental test of a microwave ion beam source in oxygen  

SciTech Connect (OSTI)

Recent experiments have demonstrated a microwave (2.45 GHz) plasma disk ion source operating with inert gases both with and without an applied static magnetic field. Earlier results were reported using a preliminary, multicusp static magnetic field configuration produced by alternating pole, small, --2.5 kG rare earth magnets surrounding the microwave discharge zone. This electrodeless ion source has been rebuilt incorporating several improvements and has been experimentally tested with different discharge diffusion lengths. The improvements include removing the rare earth magnets from the inside of the microwave cavity and embedding them in the cavity walls. The placement and strength of the magnets allows electron cyclotron resonant surfaces (--875 G) to lie entirely within the discharge zone. Discharges with different diffusion lengths were created by varying the thickness of the disk-shaped discharge zone. The experimental performance with and without a static magnetic field is discussed at the low flow rates of 2--10 sccm and using a 2.5 cm diam double grid set. Experimental test results are compared to similar ion beam sources in oxygen that employ a dc discharge. The expected lifetime, startup, and shutdown problems and maintenance are also reviewed.

Asmussen, J.; Dahimene, M.

1987-01-01T23:59:59.000Z

189

Extended-range grazing-incidence spectrometer for high-resolution extreme ultraviolet measurements on an electron beam ion trap  

SciTech Connect (OSTI)

A high-resolution grazing-incidence grating spectrometer has been implemented on the Livermore electron beam ion traps for performing very high-resolution measurements in the soft x-ray and extreme ultraviolet region spanning from below 10 Å to above 300 Å. The instrument operates without an entrance slit and focuses the light emitted by highly charged ions located in the roughly 50 ?m wide electron beam onto a cryogenically cooled back-illuminated charge-coupled device detector. The measured line widths are below 0.025 Å above 100 Å, and the resolving power appears to be limited by the source size and Doppler broadening of the trapped ions. Comparisons with spectra obtained with existing grating spectrometers show an order of magnitude improvement in spectral resolution.

Beiersdorfer, P.; Magee, E. W.; Brown, G. V.; Träbert, E.; Widmann, K. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Hell, N. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Dr. Remeis-Sternwarte and ECAP, Universität Erlangen-Nürnberg, 96049 Bamberg (Germany)

2014-11-15T23:59:59.000Z

190

Nanostructuring superconductors by ion beams: A path towards materials engineering  

SciTech Connect (OSTI)

The paper deals with nanostructuring of superconducting materials by means of swift heavy ion beams. The aim is to modify their structural, optical and electromagnetic properties in a controlled way, to provide possibility of making them functional for specific applications. Results are presented concerning flux pinning effects (implantation of columnar defects with nanosize cross section to enhance critical currents and irreversibility fields), confined flux-flow and vortex guidance, design of devices by locally tailoring the superconducting material properties, analysis of disorder-induced effects in multi-band superconductors. These studies were carried out on different kinds of superconducting samples, from single crystals to thin films, from superconducting oxides to magnesium diboride, to recently discovered iron-based superconductors.

Gerbaldo, Roberto; Ghigo, Gianluca; Gozzelino, Laura; Laviano, Francesco [Department of Applied Science and Technology, Politecnico di Torino c.so Duca degli Abruzzi 24, 10129 Torino, Italy and INFN Sez. Torino, via P. Giuria 1, 10125 Torino (Italy); Amato, Antonino; Rovelli, Alberto [INFN Laboratori Nazionali del Sud, via S. Sofia 62, 95125 Catania (Italy); Cherubini, Roberto [INFN Laboratori Nazionali di Legnaro, viale dell'Universita 2, 35020 Legnaro (Italy)

2013-07-18T23:59:59.000Z

191

Electrostatic particle trap for ion beam sputter deposition  

DOE Patents [OSTI]

A method and apparatus for the interception and trapping of or reflection of charged particulate matter generated in ion beam sputter deposition. The apparatus involves an electrostatic particle trap which generates electrostatic fields in the vicinity of the substrate on which target material is being deposited. The electrostatic particle trap consists of an array of electrode surfaces, each maintained at an electrostatic potential, and with their surfaces parallel or perpendicular to the surface of the substrate. The method involves interception and trapping of or reflection of charged particles achieved by generating electrostatic fields in the vicinity of the substrate, and configuring the fields to force the charged particulate material away from the substrate. The electrostatic charged particle trap enables prevention of charged particles from being deposited on the substrate thereby enabling the deposition of extremely low defect density films, such as required for reflective masks of an extreme ultraviolet lithography (EUVL) system.

Vernon, Stephen P. (Pleasanton, CA); Burkhart, Scott C. (Livermore, CA)

2002-01-01T23:59:59.000Z

192

Ion beam sputter target and method of manufacture  

DOE Patents [OSTI]

A target for use in an ion beam sputtering apparatus made of at least two target tiles where at least two of the target tiles are made of different chemical compositions and are mounted on a main tile and geometrically arranged on the main tile to yield a desired chemical composition on a sputtered substrate. In an alternate embodiment, the tiles are of varied thickness according to the desired chemical properties of the sputtered film. In yet another alternate embodiment, the target is comprised of plugs pressed in a green state which are disposed in cavities formed in a main tile also formed in a green state and the assembly can then be compacted and then sintered.

Higdon, Clifton; Elmoursi, Alaa A.; Goldsmith, Jason; Cook, Bruce; Blau, Peter; Jun, Qu; Milner, Robert

2014-09-02T23:59:59.000Z

193

Present and future perspectives for high energy density physics with intense heavy ion and laser beams  

E-Print Network [OSTI]

Present and future perspectives for high energy density physics with intense heavy ion and laser18, deliver an intense uranium beam that deposit about 1 kJ0g specific energy in solid matter. Using 2004! Abstract Intense heavy ion beams from the Gesellschaft für Schwerionenforschung ~GSI, Darmstadt

194

The focusing effect of cold atomic cloud with a red-detuned Gaussian beam  

E-Print Network [OSTI]

We have demonstrated an atom-optical lens, with the advantage of a small scale and flexible adjustment of the parameters, realized by a far red-detuned Gaussian laser beam perpendicular to the propagation direction of the cold atomic cloud. The one-dimensional transverse focusing effect of cold atomic clouds at the temperature order of 1 $\\mu$K freely falling through the atom-optical lens on the micron scale have been studied theoretically and then verified experimentally. It is found that theory and experiment are in good agreement.

Zhenglu Duan; Shuyu Zhou; Tao Hong; Yuzhu Wang

2015-01-28T23:59:59.000Z

195

Optical trapping and rotation of airborne absorbing particles with a single focused laser beam  

SciTech Connect (OSTI)

We measure the periodic circular motion of single absorbing aerosol particles that are optically trapped with a single focused Gaussian beam and rotate around the laser propagation direction. The scattered light from the trapped particle is observed to be directional and change periodically at 0.4–20?kHz. The instantaneous positions of the moving particle within a rotation period are measured by a high-speed imaging technique using a charge coupled device camera and a repetitively pulsed light-emitting diode illumination. The centripetal acceleration of the trapped particle as high as ?20 times the gravitational acceleration is observed and is attributed to the photophoretic forces.

Lin, Jinda; Li, Yong-qing, E-mail: liy@ecu.edu [Department of Physics, East Carolina University, Greenville, North Carolina 27858-4353 (United States)] [Department of Physics, East Carolina University, Greenville, North Carolina 27858-4353 (United States)

2014-03-10T23:59:59.000Z

196

Characterization of polymeric films subjected to lithium ion beam irradiation  

SciTech Connect (OSTI)

Two different polymeric materials that are candidate materials for use as binders for mixed uranium–plutonium oxide nuclear fuel pellets were subjected to Li ion beam irradiation, in order to simulate intense alpha irradiation. The materials (a polyethylene glycol 8000 and a microcrystalline wax) were then analyzed using a combination of mass spectrometry (MS) approaches and X-ray photoelectron spectroscopy (XPS). Samples of the irradiated PEG materials were dissolved in H2O and then analyzed using electrospray ionization-MS, which showed the formation of a series of small oligomers in addition to intact large PEG oligomers. The small oligomers were likely formed by radiation-induced homolytic scissions of the C–O and C–C bonds, which furnish radical intermediates that react by radical recombination with Hradical dot and OHradical dot. Surface analysis using SIMS revealed a heterogeneous surface that contained not only PEG-derived polymers, but also hydrocarbon-based entities that are likely surface contaminants. XPS of the irradiated PEG samples indicated the emergence of different carbon species, with peak shifts suggesting the presence of sp2 carbon atoms. Analysis of the paraffinic film using XPS showed the emergence of oxygen on the surface of the sample, and also a broadening and shifting of the C1s peak, demonstrating a change in the chemistry on the surface. The paraffinic film did not dissolve in either H2O or a H2O–methanol solution, and hence the bulk of the material could not be analyzed using electrospray. However a series of oligomers was leached from the bulk material that produced ion series in the ESI-MS analyses that were identified octylphenyl ethoxylate oligomers. Upon Li ion bombardment, these shifted to a lower average molecular weight, but more importantly showed the emergence of three new ion series that are being formed as a result of radiation damage. Surface analysis of the paraffinic polymers using SIMS produced spectra that were wholly dominated by hydrocarbon ion series, and no difference was observed between unirradiated and irradiated samples. The studies demonstrate that for the PEG-based polymers, direct evidence for radiolytic scission can be observed using ESI-MS, and suggests that both radiolytic pathways and efficiencies as a function of dose should be measurable by calibrating instrument response to the small oligomeric degradation products.

Gary S. Groenewold; W. Roger Cannon; Paul A. Lessing; Recep Avci; Muhammedin Deliorman; Mark Wolfenden; Doug W. Akers; J. Keith Jewell

2013-02-01T23:59:59.000Z

197

Excited-Level Lifetimes and Hyperfine-Structure Measurements on Ions using Collinear Laser Ion-Beam Spectroscopy  

E-Print Network [OSTI]

resolve isotopic beams of Ca+ or Cl+. However, each isotopic mass had a different velocity, and hence Doppler shift, following subsequent acceleration to and within the DSS. Consequently ion isotopes other than the dominant iso- tope had significantly...

Jin, J.; Church, David A.

1994-01-01T23:59:59.000Z

198

A Novel Detector Design for Imaging Low-Intensity Diffuse Ion Beams  

E-Print Network [OSTI]

A Novel Detector Design for Imaging Low- Intensity Diffuse Ion Beams J. Schmidt, R. de Souza, S for signal processing To image the beam scintillating fibers are used. Ionizing particles, when incident readouts for each dimension. Right: example of a beam profile. Above: EZ10EN drive electronics to control

de Souza, Romualdo T.

199

High speed measurements of neutral beam turn-on and impact of beam modulation on measurements of ion density  

SciTech Connect (OSTI)

Modulation of neutral beams on tokamaks is performed routinely, enabling background rejection for active spectroscopic diagnostics, and control of injected power and torque. We find that there exists an anomalous initial transient in the beam neutrals delivered to the tokamak that is not accounted for by the accelerator voltage and power supply current. Measurements of the charge-exchange and beam photoemission on the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] at high speed (200 ?s) reveal that the energy of the beam neutrals is constant, but the density of beam neutrals displays dramatic variation in the first 2–3 ms following beam turn-on. The impact of this beam density variation on inferred ion densities and impurity transport is presented, with suggested means to correct for the anomalous transient.

Grierson, B. A., E-mail: bgriers@pppl.gov; Grisham, L. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Burrell, K. H.; Crowley, B.; Scoville, J. T. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)

2014-10-15T23:59:59.000Z

200

Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions  

SciTech Connect (OSTI)

The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Transport using the package IBSimu [T. Kalvas et al., Rev. Sci. Instrum. 81, 02B703 (2010)], which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H{sup ?} beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

Valerio-Lizarraga, Cristhian A., E-mail: cristhian.alfonso.valerio.lizarraga@cern.ch [CERN, Geneva (Switzerland); Departamento de Investigación en Física, Universidad de Sonora, Hermosillo (Mexico); Lallement, Jean-Baptiste; Lettry, Jacques; Scrivens, Richard [CERN, Geneva (Switzerland)] [CERN, Geneva (Switzerland); Leon-Monzon, Ildefonso [Facultad de Ciencias Fisico-Matematicas, Universidad Autónoma de Sinaloa, Culiacan (Mexico)] [Facultad de Ciencias Fisico-Matematicas, Universidad Autónoma de Sinaloa, Culiacan (Mexico); Midttun, Øystein [CERN, Geneva (Switzerland) [CERN, Geneva (Switzerland); University of Oslo, Oslo (Norway)

2014-02-15T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
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201

Design and characterization of electron beam focusing for X-ray generation in novel medical imaging architecture  

SciTech Connect (OSTI)

A novel electron beam focusing scheme for medical X-ray sources is described in this paper. Most vacuum based medical X-ray sources today employ a tungsten filament operated in temperature limited regime, with electrostatic focusing tabs for limited range beam optics. This paper presents the electron beam optics designed for the first distributed X-ray source in the world for Computed Tomography (CT) applications. This distributed source includes 32 electron beamlets in a common vacuum chamber, with 32 circular dispenser cathodes operated in space charge limited regime, where the initial circular beam is transformed into an elliptical beam before being collected at the anode. The electron beam optics designed and validated here are at the heart of the first Inverse Geometry CT system, with potential benefits in terms of improved image quality and dramatic X-ray dose reduction for the patient.

Bogdan Neculaes, V., E-mail: neculaes@research.ge.com; Zou, Yun; Zavodszky, Peter; Inzinna, Louis; Zhang, Xi; Conway, Kenneth; Caiafa, Antonio; Frutschy, Kristopher; Waters, William; De Man, Bruno [GE Global Research, Niskayuna, New York 12309 (United States)] [GE Global Research, Niskayuna, New York 12309 (United States)

2014-05-15T23:59:59.000Z

202

Formation of long-range ordered quantum dots arrays in amorphous matrix by ion beam irradiation  

SciTech Connect (OSTI)

We demonstrate the production of a well ordered three-dimensional array of Ge quantum dots in amorphous silica matrix. The ordering is achieved by ion beam irradiation and annealing of a multilayer film. Structural analysis shows that quantum dots nucleate along the direction of the ion beam used for irradiation, while the mutual distance of the quantum dots is determined by the diffusion properties of the multilayer material rather than the distances between traces of ions that are used for irradiation.

Buljan, M. [Charles University in Prague, Prague 12116 (Czech Republic); Ruder Boskovic Institute, Zagreb 10000 (Croatia); Bogdanovic-Radovic, I.; Karlusic, M.; Desnica, U. V.; Radic, N.; Dubcek, P. [Ruder Boskovic Institute, Zagreb 10000 (Croatia); Drazic, G. [Jozef Stefan Institute, Ljubljana 1000 (Slovenia); Salamon, K. [Institute of Physics, Zagreb 10000 (Croatia); Bernstorff, S. [Sincrotrone Trieste, Basovizza 34012 (Italy); Holy, V. [Charles University in Prague, Prague 12116 (Czech Republic)

2009-08-10T23:59:59.000Z

203

Self-focusing of a Hermite-cosh Gaussian laser beam in a magnetoplasma with ramp density profile  

SciTech Connect (OSTI)

The early and strong self-focusing of a Hermite-cosh-Gaussian laser beam in magnetoplasma in the presence of density ramp has been observed. Focusing and de-focusing nature of the Hermite-cosh-Gaussian laser beam with decentered parameter and magnetic field has been studied, and strong self-focusing is reported. It is investigated that decentered parameter 'b' plays a significant role for the self-focusing of the laser beam and is very sensitive as in case of extraordinary mode. For mode indices, m = 0, 1, 2,?and?b = 4.00, 3.14,?and?2.05, strong self-focusing is observed. Similarly in case of ordinary mode, for m = 0, 1, 2?and?b = 4.00, 3.14, 2.049, respectively, strong self-focusing is reported. Further, it is seen that extraordinary mode is more prominent toward self-focusing rather than ordinary mode of propagation. For mode indices m = 0, 1,?and?2, diffraction term becomes more dominant over nonlinear term for decentered parameter b=0. For selective higher values of decentered parameter in case of mode indices m=0, 1,?and?2, self-focusing effect becomes strong for extraordinary mode. Also increase in the value of magnetic field enhances the self-focusing ability of the laser beam, which is very useful in the applications like the generation of inertial fusion energy driven by lasers, laser driven accelerators, and x-ray lasers.

Nanda, Vikas; Kant, Niti; Wani, Manzoor Ahmad [Department of Physics, Lovely Professional University, Phagwara 144411, Punjab (India)] [Department of Physics, Lovely Professional University, Phagwara 144411, Punjab (India)

2013-11-15T23:59:59.000Z

204

Ion beam oscillation due to fluctuation of a hot filament driven magnetized plasma  

SciTech Connect (OSTI)

Ion beam current extracted from a modified Bernas type ion source occasionally exhibits an oscillation at a frequency of several 100 kHz. Increase in the strength of a linear magnetic field induced to the ion source has either decreased or increased the frequency of this oscillation. The frequency showed an increase in proportion to the ion extraction voltage when the frequency decreased with increasing magnetic field. The change of extraction voltage did not affect the frequency when the frequency increased with the increasing magnetic field. Mechanisms causing these oscillations of an ion beam had been investigated.

Imakita, S.; Kasuya, T.; Kimura, Y.; Wada, M. [Graduate School of Engineering, Doshisha University, Kyoto 610-0321 (Japan); Miyamoto, N. [Nissin Ion Equipment Co. Ltd., Kyoto 601-8205 (Japan)

2010-02-15T23:59:59.000Z

205

An overview of the facilities, activities, and developments at the University of North Texas Ion Beam Modification and Analysis Laboratory (IBMAL)  

SciTech Connect (OSTI)

The Ion Beam Modification and Analysis Laboratory (IBMAL) at the University of North Texas includes several accelerator facilities with capabilities of producing a variety of ion beams from tens of keV to several MeV in energy. The four accelerators are used for research, graduate and undergraduate education, and industrial applications. The NEC 3MV Pelletron tandem accelerator has three ion sources for negative ions: He Alphatross and two different SNICS-type sputter ion sources. Presently, the tandem accelerator has four high-energy beam transport lines and one low-energy beam transport line directly taken from the negative ion sources for different research experiments. For the low-energy beam line, the ion energy can be varied from {approx}20 to 80 keV for ion implantation/modification of materials. The four post-acceleration beam lines include a heavy-ion nuclear microprobe; multi-purpose PIXE, RBS, ERD, NRA, and broad-beam single-event upset; high-energy ion implantation line; and trace-element accelerator mass spectrometry. The NEC 3MV single-ended Pelletron accelerator has an RF ion source mainly for hydrogen, helium and heavier inert gases. We recently installed a capacitive liner to the terminal potential stabilization system for high terminal voltage stability and high-resolution microprobe analysis. The accelerator serves a beam line for standard RBS and RBS/C. Another beamline for high energy focused ion beam application using a magnetic quadrupole lens system is currently under construction. This beam line will also serve for developmental work on an electrostatic lens system. The third accelerator is a 200 kV Cockcroft-Walton accelerator with an RF ion source. The fourth accelerator is a 2.5 MV Van de Graaff accelerator, which was in operation for last several decades is currently planned to be used mainly for educational purpose. Research projects that will be briefly discussed include materials synthesis/modification for photonic, electronic, and magnetic applications, surface sputtering and micro-fabrication of materials, development of high-energy ion microprobe systems, and educational and outreach activities.

Rout, Bibhudutta; Dhoubhadel, Mangal S.; Poudel, Prakash R.; Kummari, Venkata C.; Pandey, Bimal; Deoli, Naresh T.; Lakshantha, Wickramaarachchige J.; Mulware, Stephen J.; Baxley, Jacob; Manuel, Jack E.; Pacheco, Jose L.; Szilasi, Szabolcs; Weathers, Duncan L.; Reinert, Tilo; Glass, Gary A.; Duggan, Jerry L.; McDaniel, Floyd D. [Ion Beam Modification and Analysis Laboratory, University of North Texas, Department of Physics, 1155 Union Circle 311427, Denton, Texas 76203 (United States)

2013-07-03T23:59:59.000Z

206

Numerical study of the characteristics of the ion and fast atom beams in an end-Hall ion source  

SciTech Connect (OSTI)

An end-Hall ion source is a cylindrical magnetized device of few centimeters in length able to generate an ion beam with a current of typically 1 A and ion energies in the range of 100 eV. This ion source does not use acceleration grids, has a relatively large ion beam divergence, and is well suited for ion assisted deposition processes. In this paper, a self-consistent two-dimensional quasi-neutral model of an end-Hall ion source is used to understand the parameters controlling the characteristics of the extracted. The model results underline the role of charge exchange collisions on beam properties. The calculated energy distribution functions reveal the existence of groups of slow ions and fast neutrals. Ion mean energy corresponds to roughly 60% of the discharge voltage, while the root mean square deviation from the mean energy corresponds to about 33% of the discharge voltage, as in experiments. The influence of the position of the electron emitting source on the ion angular distribution is also shown.

Oudini, N. [Universite de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d'Energie), 118 route de Narbonne, F-31062 Toulouse Cedex 9 (France); Garrigues, L.; Hagelaar, G. J. M.; Boeuf, J. P. [Universite de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d'Energie), 118 route de Narbonne, F-31062 Toulouse Cedex 9 (France); CNRS, LAPLACE, F-31062 Toulouse (France)

2012-10-15T23:59:59.000Z

207

Ion Beam Sputter Fabrication of Micro-Grooving and Micro-Threading Tools  

SciTech Connect (OSTI)

This paper presents techniques for fabricating microscopic, nonplanar features in a variety of materials. Micro-grooving and micro-threading tools having cutting dimensions of 10-30{micro}m are made by focused ion beam sputtering and used in ultra-precision machining. Tool fabrication involves directing a 20 keV gallium beam at polished cylindrical punches made of cobalt M42 high-speed steel or C2 tungsten carbide. This creates cutting edges having radii of curvature less than 0.4 {micro}m, and rake features similar to conventional lathe tools. Clearance for minimizing frictional drag of a tool results from the sputter yield dependence on ion herd target incidence angle. Numerically controlled, ultra-precision machining with micro-grooving tools results in a close matching between tool width and feature size. Microtools controllably machine 13 {micro}m wide, 4 {micro}m deep, helical grooves in polymethyl methacrylate and 6061-T6 Al cylindrical substrates. Micro-grooving tools also fabricate sinusoidal waveform features in polished metal substrates.

ADAMS,DAVID P.; VASILE,M.J.; KRISHNAN,A.S.M.

1999-11-05T23:59:59.000Z

208

Study of nonlinear ohmic heating and ponderomotive force effects on the self-focusing and defocusing of Gaussian laser beams in collisional underdense plasmas  

SciTech Connect (OSTI)

In the present paper, the propagation characteristics of a linearly polarized gaussian laser beam in a non-isothermal underdense collisional plasma is studied. By considering the effects of the ponderomotive force and ohmic heating of plasma electrons as the nonlinear mechanisms, the second order differential equation of the dimensionless beam width parameter has been obtained and solved at several initial ion temperatures. Furthermore, by using the nonlinear dielectric permittivity of the mentioned plasma medium in the paraxial approximation and its dependence on the propagation characteristics of the gaussian laser pulse, the perturbed electron density n{sub e}/n{sub 0e} is obtained and its variation in terms of the dimensionless plasma length is analyzed at different initial ion temperatures. Our results show that the dimensionless beam width parameter is strongly influenced by the initial plasma ion temperature. It is found that, for the self-focusing regime, the plasma electron density perturbation continuously oscillates between the initial density distribution and a minimum, and for the defocusing regime, the plasma electron density perturbation continuously oscillates between the initial density distribution and a maximum.

Etehadi Abari, M.; Shokri, B. [Physics Department and Laser-Plasma Research Institute of Shahid Beheshti University, G.C., Evin, Tehran (Iran, Islamic Republic of)

2012-11-15T23:59:59.000Z

209

An Ion Guide for the Production of a Low Energy Ion Beam of Daughter Products of $?$-Emitters  

E-Print Network [OSTI]

A new ion guide has been modeled and tested for the production of a low energy ($\\approx$ 40 kV) ion beam of daughter products of alpha-emitting isotopes. The guide is designed to evacuate daughter recoils originating from the $\\alpha$-decay of a $^{233}$U source. The source is electroplated onto stainless steel strips and mounted along the inner walls of an ion guide chamber. A combination of electric fields and helium gas flow transport the ions through an exit hole for injection into a mass separator. Ion guide efficiencies for the extraction of $^{229}$Th$^{+}$ (0.06%), $^{221}$Fr$^{+}$ (6%), and $^{217}$At$^{+}$ (6%) beams have been measured. A detailed study of the electric field and gas flow influence on the ion guide efficiency is described for two differing electric field configurations.

B. Tordoff; T. Eronen; V. V. Elomaa; S. Gulick; U. Hager; P. Karvonen; T. Kessler; J. Lee; I. Moore; A. Popov; S. Rahaman; S. Rinta-Antila; T. Sonoda; J. Aysto

2006-05-22T23:59:59.000Z

210

Dynamic Faraday cup signal analysis and the measurement of energetic ions emitted by plasma focus  

SciTech Connect (OSTI)

A theoretical model is developed to study the signals from a typical dynamic Faraday cup, and using this model the output signals from this structure are obtained. A detailed discussion on the signal structure, using different experimental conditions, is also given. It is argued that there is a possibility of determining the total charge of the generated ion pulse, the maximum velocity of the ions, ion velocity distribution, and the number of ion species for mixed working gases, under certain conditions. In addition, the number of different ionization stages, the number of different pinches in one shot, and the number of different existing acceleration mechanisms can also be determined provided that the mentioned conditions being satisfied. An experiment is carried out on the Filippov type 90?kJ Sahand plasma focus using Ar as the working gas at the pressure of 0.25?Torr. The data from a typical shot are fitted to a signal from the model and the total charge of the related energetic ion pulse is deduced using the values of the obtained fit parameters. Good agreement between the obtained amount of the total charge and the values obtained during other experiments on the same plasma focus device is observed.

Pestehe, S. J., E-mail: sjpest@tabrizu.ac.ir; Mohammadnejad, M. [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Tabriz 5167618949 (Iran, Islamic Republic of) [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Tabriz 5167618949 (Iran, Islamic Republic of); Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz (Iran, Islamic Republic of); Irani Mobaraki, S. [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Tabriz 5167618949 (Iran, Islamic Republic of)] [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Tabriz 5167618949 (Iran, Islamic Republic of)

2014-03-15T23:59:59.000Z

211

Applications of laser produced ion beams to nuclear analysis of materials  

SciTech Connect (OSTI)

Laser produced ion beams have unique characteristics which are ultra-short pulse, very low emittance, and variety of nuclear species. These characteristics could be used for analyzing various materials like low Z ion doped heavy metals or ceramics. Energies of laser produced ion beam extend from 0.1MeV to 100MeV. Therefore, various nuclear processes can be induced in the interactions of ion beams with samples. The ion beam driven nuclear analysis has been developed for many years by using various electrostatic accelerators. To explore the applicability of laser ion beam to the analysis of the Li ion battery, a proton beam with the diameter of {approx} 1.0 {mu}m at Takasaki Ion Acceleration for Advanced Radiation Application (TIARA), JAEA was used. For the analysis, the PIGE (Particle-Induced Gamma Ray Emission) is used. The proton beam scans over Li battery electrode samples to diagnose Li density in the LiNi{sub 0.85}Co{sub 0.15}O{sub 2} anode. As the results, PIGE images for Li area density distributions are obtained with the spatial resolution of better than 1.5{mu}m FWHM. By the Li PIGE images, the depth dependence of de-intercalation levels of Li in the anode is obtained. By the POP experiments at TIARA, it is clarified that laser produced ion beam is appropriate for the Li ion battery analysis. 41.85.Lc, 41.75.Jv, 42.62.cf.

Mima, K.; Azuma, H.; Fujita, K.; Yamazaki, A.; Okuda, C.; Ukyo, Y.; Kato, Y.; Arrabal, R. Gonzalez; Soldo, F.; Perlado, J. M.; Nishimura, H.; Nakai, S. [Graduate School for the Creation of New Photonics Industries, Shizuoka (Japan) and Institute de Fusion Nuclear, Universidad Politecnica de Madrid, Madrid (Spain) and Institute of Laser Engineering, Osaka University, Osaka (Japan); Toyota Central R and D Labs., Inc., Aichi (Japan); Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), Gunnma (Japan); Toyota Central R and D Labs., Inc., Aichi (Japan)

2012-07-11T23:59:59.000Z

212

Formation of Cobalt Silicide Films by Ion Beam Deposition  

SciTech Connect (OSTI)

Thin films of cobalt silicide are widely used as metallization in very large-scale integrated electronic circuits. In this study, Co ions were deposited on Si (111) wafers by a high beam current filter metal vacuum arc deposition (FMEVAD) system. Surface silicide films were formed after annealing from 500 to 700 C for 30 minutes. Cobalt depth profiles and contaminations were determined using Rutherford backscattering spectrometry (RBS) and time-of-flight energy elastic recoil detection analysis (ToF-E ERDA). The polycrystalline cobalt silicide phases formed were characterized by grazing-incidence x-ray diffraction (GIXRD). The surface topography development and interfaces have been investigated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results show that a thin CoSi2 surface layer with both a smooth surface topography and sharp interface can be achieved by annealing at 700 C. The CoSi phase and O contamination were observed in the samples that were annealed at lower temperatures.

Zhang, Yanwen; McCready, David E.; Wang, Chong M.; Young, James S.; Mckinley, Mathew I.; Whitlow, Harry J.; Razpet, Alenka; Possnert, Göran; Zhang, Tonghe; Wu, Yuguang

2006-01-01T23:59:59.000Z

213

Acoustic radiation force on a double-layer microsphere by a Gaussian focused beam  

SciTech Connect (OSTI)

A new model for calculating the radiation force on double-layer microsphere is proposed based on the ray acoustics approach. The axial acoustic radiation force resulting from a focused Gaussian beam incident on spherical shells immersed in water is examined theoretically in relation to its thickness and the contents of its double-layer. The attenuation both in the water and inside the sphere is considered in this method, which cannot be ignored while the high frequency ultrasonic is used. Results of numerical calculations are presented for fat and low density polyethylene materials, with the hollow region filled with animal oil, water, or air. These results show how the acoustic impedance and the sound velocity of both layers, together with the thickness of the shell, affect the acoustic radiation force.

Wu, Rongrong; Cheng, Kaixuan; Liu, Jiehui; Mao, Yiwei; Gong, Xiufen [Key Laboratory of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); Liu, Xiaozhou, E-mail: xzliu@nju.edu.cn [Key Laboratory of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190 (China)

2014-10-14T23:59:59.000Z

214

Turning point temperature and competition between relativistic and ponderomotive effects in self-focusing of laser beam in plasma  

SciTech Connect (OSTI)

The propagation characters of Gaussian laser beam in collisionless plasma are investigated by considering the ponderomotive and relativistic nonlinearities. The second-order differential equation of dimensionless beam width parameter is solved numerically, taking into account the effect of electron temperature. The results show that the ponderomotive force does not facilitate the relativistic self-focusing in all intensity ranges. In fact, there exists a certain intensity value that, if below this value, the ponderomotive nonlinearity can contribute to the relativistic self-focusing, or obstruct it, if above. It is also indicated that there is a temperature interval in which self-focusing can occur, while the beam diverges outside of this region. In addition, the results represent the existence of a “turning point temperature” in the mentioned interval that the self-focusing has the strongest power. The value of the turning point is dependent on laser intensity in which higher intensities result in higher turning point.

Bokaei, B.; Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of)] [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of); Jafari Milani, M. R. [Plasma Physics Research School, Tehran (Iran, Islamic Republic of)] [Plasma Physics Research School, Tehran (Iran, Islamic Republic of)

2013-10-15T23:59:59.000Z

215

Survey of Collective Instabilities and Beam-Plasma Interactions in Intense Heavy Ion Beams  

E-Print Network [OSTI]

H. Qin, Phys. Rev. ST Accel. Beams 4, 104401 (2001). [30] S.Davidson, Phys. Rev. ST Accel. Beams 5, 021001 (2002). [31]Channell, Phys. Rev. ST Accel. Beams 2, 074401 (1999); [32

Davidson, Ronald C.

2009-01-01T23:59:59.000Z

216

Ion beam energy spectrum calculation via dosimetry data deconvolution.  

SciTech Connect (OSTI)

The energy spectrum of a H{sup +} beam generated within the HERMES III accelerator is calculated from dosimetry data to refine future experiments. Multiple layers of radiochromic film are exposed to the beam. A graphic user interface was written in MATLAB to align the film images and calculate the beam's dose depth profile. Singular value regularization is used to stabilize the unfolding and provide the H{sup +} beam's energy spectrum. The beam was found to have major contributions from 1 MeV and 8.5 MeV protons. The HERMES III accelerator is typically used as a pulsed photon source to experimentally obtain photon impulse response of systems due to high energy photons. A series of experiments were performed to explore the use of Hermes III to generate an intense pulsed proton beam. Knowing the beam energy spectrum allows for greater precision in experiment predictions and beam model verification.

Harper-Slaboszewicz, Victor Jozef; Sharp, Andrew Clinton (A& M University, College Station, TX)

2010-10-01T23:59:59.000Z

217

Pulsed-ion-beam nitriding and smoothing of titanium surface in a vacuum  

SciTech Connect (OSTI)

Both nitriding and smoothing of titanium have been achieved under irradiation of intense pulsed ion beam in a vacuum of 2x10{sup -2} Pa. Applying a screening method, we find that medium ion-beam intensity and multi-shot irradiation are effective for the processing, where repetitive surface melting with limited ablation favored Ti nitride formation as well as surface smoothing. The present results demonstrate that ambient gas atoms/molecules can be efficiently incorporated in metal matrices to form compounds under the ion-beam irradiation. The finding is of great significance for extending application scope of the ion-beam technique in materials research and processing, combined with the recent success in introducing ambient gas into the processing chamber.

Zhu, X.P.; Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi; Lei, M.K. [Extreme Energy-Density Research Institute, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Surface Engineering Laboratory, Department of Materials Engineering, Dalian University of Technology, Dalian 116024 (China)

2005-08-29T23:59:59.000Z

218

Direct drive heavy-ion-beam inertial fusion at high coupling efficiency  

E-Print Network [OSTI]

M J of fusion yield. This NIF capsule design ab- sorbs 200capsules the size of the NIF capsule with heavy-ion beams (designs emerge, and, if the NIF's ignition campaign is also

Logan, B.G.

2008-01-01T23:59:59.000Z

219

Direct Drive Heavy-Ion-Beam Inertial Fusion at High Coupling Efficiency  

E-Print Network [OSTI]

of fusion yield [16]. This NIF capsule design absorbs 200 kJcapsules the size of the NIF capsule with heavy ion beams (designs emerge, and, i f the NIF's ignition campaign is also

Logan, B. Grant

2008-01-01T23:59:59.000Z

220

Investigation into direct conversion with medium energy He-ion beams  

E-Print Network [OSTI]

INVESTIGATION INTO DIRECT ENERGY CONVERSION WITH MEDIUM ENERGY HELIUM-ION BEAMS A Thesis by AVERY ALLAN GUILD-BINGHAM Submitted to the Office of Graduate Studies of Texas A&M University in partial... fulfillment of the requirements for the degree of MASTER OF SCIENCE December 2004 Major Subject: Nuclear Engineering INVESTIGATION INTO DIRECT ENERGY CONVERSION WITH MEDIUM ENERGY HELIUM-ION BEAMS A Thesis...

Guild-Bingham, Avery A.

2005-02-17T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Saturation of multi-laser beams laser-plasma instabilities from stochastic ion heating  

SciTech Connect (OSTI)

Cross-beam energy transfer (CBET) has been used as a tool on the National Ignition Facility (NIF) since the first energetics experiments in 2009 to control the energy deposition in ignition hohlraums and tune the implosion symmetry. As large amounts of power are transferred between laser beams at the entrance holes of NIF hohlraums, the presence of many overlapping beat waves can lead to stochastic ion heating in the regions where laser beams overlap [P. Michel et al., Phys. Rev. Lett. 109, 195004 (2012)]. This increases the ion acoustic velocity and modifies the ion acoustic waves’ dispersion relation, thus reducing the plasma response to the beat waves and the efficiency of CBET. This pushes the plasma oscillations driven by CBET in a regime where the phase velocities are much smaller than both the electron and ion thermal velocities. CBET gains are derived for this new regime and generalized to the case of multi ion species plasmas.

Michel, P.; Williams, E. A.; Divol, L.; Berger, R. L.; Glenzer, S. H.; Callahan, D. A. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Rozmus, W. [Theoretical Physics Institute, University of Alberta, Edmonton, Alberta T6G2G7 (Canada) [Theoretical Physics Institute, University of Alberta, Edmonton, Alberta T6G2G7 (Canada); Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

2013-05-15T23:59:59.000Z

222

Concentrated ion beam emitted from an enlarged cylindrical-anode-layer Hall plasma accelerator and mechanism  

SciTech Connect (OSTI)

An enlarged cylindrical-anode-layer Hall plasma accelerator with an outlet diameter of 150 mm is experimentally demonstrated to produce a concentrated ion beam, especially at a high discharge voltage, with a high current utilization efficiency of up to {approx}0.9. Numerical investigation based on the three-dimensional particle-in-cell method is performed to study the ion dynamics and elucidate the origin of the ion beam characteristics. The simulation results reveal that the equipotential lines play an important role in the surface near the anode emitting the ions. The ion emitting surface is determined by the magnetic field lines near the anode and the magnetic mirror contributes to the concentrated beam significantly. The high current utilization efficiency results from the appropriate obliquity of the magnetic mirror.

Geng, S. F.; Wang, C. X. [Southwestern Institute of Physics, Chengdu 610041 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Tang, D. L.; Qiu, X. M. [Southwestern Institute of Physics, Chengdu 610041 (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

2013-01-28T23:59:59.000Z

223

Means and method for the focusing and acceleration of parallel beams of charged particles  

DOE Patents [OSTI]

A novel apparatus and method for focussing beams of charged particles comprising planar arrays of electrostatic quadrupoles. The quadrupole arrays may comprise electrodes which are shared by two or more quadrupoles. Such quadrupole arrays are particularly adapted to providing strong focussing forces for high current, high brightness, beams of charged particles, said beams further comprising a plurality of parallel beams, or beamlets, each such beamlet being focussed by one quadrupole of the array. Such arrays may be incorporated in various devices wherein beams of charged particles are accelerated or transported, such as linear accelerators, klystron tubes, beam transport lines, etc.

Maschke, Alfred W. (East Moriches, NY)

1983-07-05T23:59:59.000Z

224

Intense Ion Beam for Warm Dense Matter Physics  

E-Print Network [OSTI]

limit the ?ow of plasma into the ?nal focus solenoid. Onceneutralizing plasma that enables us to focus to emittanceplasma is strongly coupled to the ?eld lines provided by the ? nal focus

Heimbucher, Lynn

2008-01-01T23:59:59.000Z

225

Ion source developments for the production of radioactive isotope beams at TRIUMF  

SciTech Connect (OSTI)

At the ISAC facility at TRIUMF radioactive ions are produced by bombarding solid targets with up to 100 ?A of 500 MeV protons. The reaction products have to diffuse out of the hot target into an ion source. Normally, singly charged ions are extracted. They can be transported either directly to experiments or via an ECR charge state breeder to a post accelerator. Several different types of ion sources have to be used in order to deliver a large variety of rare isotope beams. At ISAC those are surface ion sources, forced electron beam arc discharge (FEBIAD) ion sources and resonant laser ionization sources. Recent development activities concentrated on increasing the selectivity for the ionization to suppress isobaric contamination in the beam. Therefore, a surface ion rejecting resonant laser ionization source (SIRLIS) has been developed to suppress ions from surface ionization. For the FEBIAD ion source a cold transfer line has been introduced to prevent less volatile components from reaching the ion source.

Ames, F., E-mail: ames@triumf.ca; Bricault, P.; Heggen, H.; Kunz, P.; Lassen, J.; Mjøs, A.; Raeder, S.; Teigelhöfer, A. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T2A3 (Canada)] [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T2A3 (Canada)

2014-02-15T23:59:59.000Z

226

HIGH ENERGY DENSITY PHYSICS EXPERIMENTS WITH INTENSE HEAVY ION BEAMS  

E-Print Network [OSTI]

used to inject plasma into the final focus region right inplasma flow is slowed down once entering the high field region of the final focus

Bieniosek, F.M.

2008-01-01T23:59:59.000Z

227

HIGH ENERGY DENSITY PHYSICS EXPERIMENTS WITH INTENSE HEAVY ION BEAMS  

E-Print Network [OSTI]

used to inject plasma into the final focus region right inplasma flow is slowed down once entering the high field region of the final focus

Henestroza, E.

2012-01-01T23:59:59.000Z

228

Chapter 2 Deuterium Reaction with C(100): IonBeam Scattering Experiment  

E-Print Network [OSTI]

­beam scattering techniques are easily calibrated by compari­ #12; 28 son to ion­implanted standards, and nuclear of 1560 ffi C from time­of­flight scattering and recoil­ion spectroscopy (TOF­SARS). However, Chin et al

Goddard III, William A.

229

Multiple-ion-beam time-of-flight mass spectrometer Andreas Rohrbacher and Robert E. Continettia)  

E-Print Network [OSTI]

/ionization and the molecular ions of two different proteins myoglobin and lysozyme , created by matrix assisted laser,7 and matrix assisted desorption and ionization MALDI 8­11 have become avail- able to allow the mass the samples with a robot- driven capillary,15 a scanning ion beam,16 or spatial resolu- tion was achieved

Continetti, Robert E.

230

Fundamental studies of the plasma extraction and ion beam formation processes in inductively coupled plasma mass spectrometry  

SciTech Connect (OSTI)

The fundamental and practical aspects are described for extracting ions from atmospheric pressure plasma sources into an analytical mass spectrometer. Methodologies and basic concepts of inductively coupled plasma mass spectrometry (ICP-MS) are emphasized in the discussion, including ion source, sampling interface, supersonic expansion, slumming process, ion optics and beam focusing, and vacuum considerations. Some new developments and innovative designs are introduced. The plasma extraction process in ICP-MS was investigated by Langmuir measurements in the region between the skimmer and first ion lens. Electron temperature (T{sub e}) is in the range 2000--11000 K and changes with probe position inside an aerosol gas flow. Electron density (n{sub e}) is in the range 10{sup 8}--10{sup 10} {sup {minus}cm }at the skimmer tip and drops abruptly to 10{sup 6}--10{sup 8} cm{sup {minus}3} near the skimmer tip and drops abruptly to 10{sup 6}--10{sup 8} cm{sup {minus}3} downstream further behind the skimmer. Electron density in the beam leaving the skimmer also depends on water loading and on the presence and mass of matrix elements. Axially resolved distributions of electron number-density and electron temperature were obtained to characterize the ion beam at a variety of plasma operating conditions. The electron density dropped by a factor of 101 along the centerline between the sampler and skimmer cones in the first stage and continued to drop by factors of 10{sup 4}--10{sup 5} downstream of skimmer to the entrance of ion lens. The electron density in the beam expansion behind sampler cone exhibited a 1/z{sup 2} intensity fall-off (z is the axial position). An second beam expansion originated from the skimmer entrance, and the beam flow underwent with another 1/z{sup 2} fall-off behind the skimmer. Skimmer interactions play an important role in plasma extraction in the ICP-MS instrument.

Niu, Hongsen

1995-02-10T23:59:59.000Z

231

Development of hollow electron beams for proton and ion collimation  

SciTech Connect (OSTI)

Magnetically confined hollow electron beams for controlled halo removal in high-energy colliders such as the Tevatron or the LHC may extend traditional collimation systems beyond the intensity limits imposed by tolerable material damage. They may also improve collimation performance by suppressing loss spikes due to beam jitter and by increasing capture efficiency. A hollow electron gun was designed and built. Its performance and stability were measured at the Fermilab test stand. The gun will be installed in one of the existing Tevatron electron lenses for preliminary tests of the hollow-beam collimator concept, addressing critical issues such as alignment and instabilities of the overlapping proton and electron beams.

Stancari, G.; Drozhdin, A.I.; Kuznetsov, G.; Shiltsev, V.; Still, D.A.; Valishev, A.; Vorobiev, L.G.; /Fermilab; Assmann, R.; /CERN; Kabantsev, A.; /UC, San Diego

2010-06-01T23:59:59.000Z

232

Theoretical and Experimental Studies of the Extracted MCI Beam from an ECR Ion Source  

SciTech Connect (OSTI)

With the development of Electron Cyclotron Resonance Ion Source (ECRIS), very high performance ECRIS nowadays have been set up one by one around the world, such as the GTS in Grenoble, SERSE in Catania, LECR3 in Lanzhou and etc, which can produce very intense Multiply Charged Ion (MCI) beam. But till now, the study of the extracted MCI beam from an ECRIS remains open. In this article, we present a theoretical and experimental study of the extracted MCI beam. In the theoretical part, the influences of the extraction system on the extracted ion beam quality are mainly analyzed. The aspects that have influences on the extracted ion beam quality have been analyzed. With the instruction of the analysis, the PBGUNS code is used to simulate the influences of some important aspects concerning the extraction system. The influences of the extraction system geometry design, magnetic field, and the space charge effect will be detailedly presented in this article. In the experimental part, with an Electric-Sweep Scanner (ESS) emittance detection system, the influences on the extracted ion beam emittance of some typical parameters of ECRIS have been researched, such as the injected RF power, the RF frequency, the magnetic field and etc. The obtained results and the corresponding explanations are presented. Some of the results are well in accord with some empirical laws, but some other results seem to be disputed.

Sun, L.T.; Cao, Y.; Zhao, H.W.; Guo, X.H.; Zhang, Z.M.; Feng, Y.C.; Li, J.Y.; Ma, L.; Li, J.; Zhao, H.Y.; He, W.; Li, X.X. [Institute of Modern Physics (IMP), Chinese Academy of Sciences, Lanzhou (China); Hitz, D.; Girard, A. [CEA-Grenoble, Departement de Recherche Fondamentale sur la Matiere Condensee, Service des Basses Temperatures, 17 Rue des Martyrs, 38054 Grenoble Cedex 9 (France)

2005-03-15T23:59:59.000Z

233

LEEM investigations of clean surfaces driven by energetic ion beams  

SciTech Connect (OSTI)

The original purpose of this award was to use low?energy electron microscopy (LEEM) to explore the dynamics of surfaces of clean single crystal surfaces when driven by a beam of energetic ions. The goal was to understand the nanoscience of hyperthermal growth, surface erosion by sublimation and irradiation, operation of surface sinks in irradiated materials, diffusion on driven surfaces, and the creation of structural patterns. This project was based on a novel LEEM system constructed by C. P. Flynn, which provided real?time imaging of surface dynamics by scattering low energy electrons. With the passing of Prof. Flynn in late 2011, this project was completed under a slightly different scope by constructing a low?energy, inelastic electron scattering (?EELS?) instrument. Consistent with Flynn?s original objectives for his LEEM system, this device probes the dynamics of crystal surfaces. However the measurements are not carried out in real time, but instead are done in the frequency domain, through the energy lost from the probe electrons. The purpose of this device is to study the collective bosonic excitations in a variety of materials, including high temperature superconductors, topological insulators, carbon allotropes including (but not limited to) graphene, etc. The ultimate goal here is to identify the bosons that mediate interactions in these and other materials, with hopes of shedding light on the origin of many exotic phenomena including high temperature superconductivity. We completed the construction of a low?energy EELS system that operates with an electron kinetic energy of 7 - 10 eV. With this instrument now running, we hope to identify, among other things, the bosons that mediate pairing in high temperature superconductors. Using this instrument, we have already made our first discovery. Studying freshly cleaved single crystals of Bi{sub 2}Se{sub 3}, which is a topological insulator, we have observed a surface excitation at an energy loss of ~ 90 meV. This excitation disperses quadratically, exhibits a critical momentum of q{sub c} = 0.11 ?{sup ?1}, and may be identified as the surface collective mode of the helical Dirac liquid. To make a stronger connection between the behavior of this excitation and the known surface physics of Bi{sub 2}Se{sub 3}, we are carrying out a doping?dependent study, as a function of Se vacancy content, of this excitation. From this study we will be able to quantify the strength of interactions in the spin?polarized surface states in a manner analogous to our past work on graphene.

Abbamonte, Peter M. [University of Illinois] University of Illinois

2013-04-24T23:59:59.000Z

234

A pepper-pot emittance meter for low-energy heavy-ion beams  

SciTech Connect (OSTI)

A novel emittance meter has been developed to measure the four-dimensional, transverse phase-space distribution of a low-energy ion beam using the pepper-pot technique. A characteristic feature of this instrument is that the pepper-pot plate, which has a linear array of holes in the vertical direction, is scanned horizontally through the ion beam. This has the advantage that the emittance can also be measured at locations along the beam line where the beam has a large horizontal divergence. A set of multi-channel plates, scintillation screen, and ccd camera is used as a position-sensitive ion detector allowing a large range of beam intensities that can be handled. This paper describes the design, construction, and operation of the instrument as well as the data analysis used to reconstruct the four-dimensional phase-space distribution of an ion beam. Measurements on a 15 keV He{sup +} beam are used as an example.

Kremers, H. R.; Beijers, J. P. M.; Brandenburg, S. [Kernfysisch Versneller Instituut, University of Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands)

2013-02-15T23:59:59.000Z

235

Investigation of effect of solenoid magnet on emittances of ion beam from laser ablation plasma  

SciTech Connect (OSTI)

A magnetic field can increase an ion current of a laser ablation plasma and is expected to control the change of the plasma ion current. However, the magnetic field can also make some fluctuations of the plasma and the effect on the beam emittance and the emission surface is not clear. To investigate the effect of a magnetic field, we extracted the ion beams under three conditions where without magnetic field, with magnetic field, and without magnetic field with higher laser energy to measure the beam distribution in phase space. Then we compared the relations between the plasma ion current density into the extraction gap and the Twiss parameters with each condition. We observed the effect of the magnetic field on the emission surface.

Ikeda, Shunsuke, E-mail: shunsuke.ikeda@riken.jp; Sekine, Megumi [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan) [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan); Riken, Wako, Saitama (Japan); Romanelli, Mark [Cornell University, Ithaca, New York 14850 (United States)] [Cornell University, Ithaca, New York 14850 (United States); Cinquegrani, David [University of Michigan, Ann Arbor, Michigan 48109 (United States)] [University of Michigan, Ann Arbor, Michigan 48109 (United States); Kumaki, Masafumi [Waseda University, Shinjuku, Tokyo (Japan)] [Waseda University, Shinjuku, Tokyo (Japan); Fuwa, Yasuhiro [Kyoto University, Uji, Kyoto (Japan)] [Kyoto University, Uji, Kyoto (Japan); Kanesue, Takeshi; Okamura, Masahiro [Brookhaven National Laboratory, Upton, New York 11973 (United States)] [Brookhaven National Laboratory, Upton, New York 11973 (United States); Horioka, Kazuhiko [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan)] [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan)

2014-02-15T23:59:59.000Z

236

VOLUME 76, NUMBER 23 P H Y S I C A L R E V I E W L E T T E R S 3 JUNE 1996 Small Beam Nonparaxiality Arrests Self-Focusing of Optical Beams  

E-Print Network [OSTI]

VOLUME 76, NUMBER 23 P H Y S I C A L R E V I E W L E T T E R S 3 JUNE 1996 Small Beam Nonparaxiality Arrests Self-Focusing of Optical Beams Gadi Fibich Department of Mathematics, University-focusing in the presence of small beam nonparaxiality is derived. Analysis of this equation shows that nonparaxiality

Fibich, Gadi

237

Ion-beam driven lower hybrid waves in a magnetized dusty plasma  

SciTech Connect (OSTI)

An ion beam drives lower hybrid waves to instability in a magnetized dusty plasma via Cerenkov interaction. A dispersion relation and the growth rate of the lower hybrid waves have been derived taking into account the dust charge fluctuations. The frequency and the growth rate of the unstable wave instability increase with relative density of negatively charged dust grains. The lower hybrid modes with phase velocity comparable to the beam velocity possess a large growth rate. Moreover, the growth rate of the instability increases with beam density and scales as the one-third power of the beam density.

Prakash, Ved; Vijayshri [School of Sciences, Indira Gandhi National Open University, Maidan Garhi, New Delhi 110 068 (India)] [School of Sciences, Indira Gandhi National Open University, Maidan Garhi, New Delhi 110 068 (India); Sharma, Suresh C. [Department of Applied Physics, Delhi Technological University, Shahbad Daulatpur, Bawana Road, Delhi 110 042 (India)] [Department of Applied Physics, Delhi Technological University, Shahbad Daulatpur, Bawana Road, Delhi 110 042 (India); Gupta, Ruby [Department of Physics, Swami Shraddhanand College, University of Delhi, Alipur, Delhi 110 036 (India)] [Department of Physics, Swami Shraddhanand College, University of Delhi, Alipur, Delhi 110 036 (India)

2013-06-15T23:59:59.000Z

238

Ion boundary conditions in semi-infinite fluid models of electron beam-plasma interaction  

SciTech Connect (OSTI)

The modified Bohm criterion is derived for the plasma consisting of the monoenergetic electron beam and thermal electrons. This criterion allows us to define the accurate ion boundary conditions for semi-infinite collisionless fluid models of electron beam–plasma interaction. In the absence of electron beam, these boundary conditions give the classical sheath parameters. When the monoenergetic electron beam propagates through the plasma, the fluid model with proposed boundary conditions gives the results, which are in qualitative agreement with the results obtained earlier in M. Sharifian and B. Shokri, Phys. Plasmas 14, 093503 (2007). However, dynamics and parameters of the plasma sheath are different.

Levko, Dmitry [LAPLACE (Laboratoire Plasma et Conversion d'Energie), Universite de Toulouse, UPS, INPT Toulouse, 118 route de Narbonne, F-31062 Toulouse cedex 9 (France)

2014-10-15T23:59:59.000Z

239

Ion Beam Nanosculpting and Materials Science with Single Nanopores  

SciTech Connect (OSTI)

Work is reported in these areas: Nanopore studies; Ion sculpting of metals; High energy ion sculpting; Metrology of nanopores with single wall carbon nanotube probes; Capturing molecules in a nanopore; Strand separation in a nanopore; and DNA molecules and configurations in solid-state nanopores.

Golovchenko, J A; Branton, D

2009-10-03T23:59:59.000Z

240

Progress in Beam Focusing and Compression for Target Heating and Warm Dense Matter Experiments  

E-Print Network [OSTI]

plasma and the plasma in the final focus solenoid, whichplasma forms a thin column of diameter ~5 mm along the solenoid axis when the Final Focus

Seidl, Peter

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Intense Ion Beam for Warm Dense Matter Physics  

E-Print Network [OSTI]

waveform and there are voltage oscillations. Before reachingbunching of the beam. Voltage oscillations in the diode alsoThe period T of the voltage oscillation must be t a < T < t

Heimbucher, Lynn

2008-01-01T23:59:59.000Z

242

Effective shielding to measure beam current from an ion source  

SciTech Connect (OSTI)

To avoid saturation, beam current transformers must be shielded from solenoid, quad, and RFQ high stray fields. Good understanding of field distribution, shielding materials, and techniques is required. Space availability imposes compact shields along the beam pipe. This paper describes compact effective concatenated magnetic shields for IFMIF-EVEDA LIPAc LEBT and MEBT and for FAIR Proton Linac injector. They protect the ACCT Current Transformers beyond 37 mT radial external fields. Measurements made at Saclay on the SILHI source are presented.

Bayle, H., E-mail: bayle@bergoz.com [Bergoz Instrumentation, Saint-Genis-Pouilly (France); Delferrière, O.; Gobin, R.; Harrault, F.; Marroncle, J.; Senée, F.; Simon, C.; Tuske, O. [CEA, Saclay (France)] [CEA, Saclay (France)

2014-02-15T23:59:59.000Z

243

Reactive ion beam etching of HfO{sub 2} film and removal of sidewall redeposition  

SciTech Connect (OSTI)

Comparative studies on ion beam etching (IBE) and reactive ion beam etching (RIBE) of HfO{sub 2} film have been carried out using photoresist as the masking layer. The etching rates of HfO{sub 2} film and photoresist mask in pure Ar and Ar/CHF{sub 3} mixture plasmas were measured as a function of ion energy, plasma composition, and ion beam incident angle. It has been found that the RIBE with Ar/CHF{sub 3} plasma is capable of lowering the threshold energy of ion beam and increasing sputtering yield, compared to the IBE with pure Ar. The redeposition of photoresist sidewall is a major issue, due to the formation of nonvolatile etching products during sputtering of HfO{sub 2} film in both IBE and RIBE. However, the sidewall redeposition can be easily removed in HCl solutions with assistance of ultrasonic wave for RIBE with Ar/CHF{sub 3} plasma. Alternatively, the sidewall redeposition can be eliminated by controlling the slope of photoresist sidewall or combined with ion incident angle.

Wang Xudi; Liu Ying; Xu Xiangdong; Fu Shaojun; Cui Zheng [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026 (China) and School of Mechanical and Automobile Engineering, Hefei University of Technology, Hefei 230009 (China); National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026 (China); Central Microstructure Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom)

2006-07-15T23:59:59.000Z

244

Relativistic and ponderomotive self-focusing of a laser beam in a radially inhomogeneous plasma. I. Paraxial approximation  

SciTech Connect (OSTI)

The propagation of a high-irradiance laser beam in a plasma whose optical index depends nonlinearly on the light intensity is investigated through both theoretical and numerical analyses. The nonlinear effects examined herein are the relativistic decrease of the plasma frequency and the ponderomotive expelling of the electrons. This paper is devoted to focusing and defocusing effects of a beam assumed to remain cylindrical and for a plasma supposed homogeneous along the propagation direction but radially inhomogeneous with a parabolic density profile. A two-parameter perturbation expansion is used; these two parameters, assumed small with respect to unity, are the ratio of the laser wavelength to the radial electric-field gradient length and the ratio of the plasma frequency to the laser frequency. The laser field is described in the context of a time envelope and spatial paraxial approximations. An analytical expression is provided for the critical beam power beyond which self-focusing appears; it depends strongly on the plasma inhomogeneity and suggests the plasma density tailoring in order to lower this critical power. The beam energy radius evolution is obtained as a function of the propagation distance by numerically solving the paraxial equation given by the two-parameter expansion. The relativistic mass variation is shown to dominate the ponderomotive effect. For strong laser fields, self-focusing saturates due to corrections of fourth order in the electric field involved by both contributions.

Brandi, H.S.; Manus, C.; Mainfray, G. (Service des Photons, Atomes et Molecules, Centre d' Etudes de Saclay, Bat. 522, 91191 Gif-sur-Yvette Cedex (France)); Lehner, T. (Laboratoire PMI, Ecole Polytechnique, 91128 Palaiseau (France)); Bonnaud, G. (Commissariat a l'Energie Atomique, Centre d'Etudes de Limeil-Valenton, 94195 Villeneuve-St-Georges (France))

1993-10-01T23:59:59.000Z

245

Emulation of reactor irradiation damage using ion beams  

SciTech Connect (OSTI)

The continued operation of existing light water nuclear reactors and the development of advanced nuclear reactor depend heavily on understanding how damage by radiation to levels degrades materials that serve as the structural components in reactor cores. The first high dose ion irradiation experiments on a ferritic-martensitic steel showing that ion irradiation closely emulates the full radiation damage microstructure created in-reactor are described. Ferritic-martensitic alloy HT9 (heat 84425) in the form of a hexagonal fuel bundle duct (ACO-3) accumulated 155 dpa at an average temperature of 443°C in the Fast Flux Test Facility (FFTF). Using invariance theory as a guide, irradiation of the same heat was conducted using self-ions (Fe++) at 5 MeV at a temperature of 460°C and to a dose of 188 displacements per atom. The void swelling was nearly identical between the two irradiations and the size and density of precipitates and loops following ion irradiation are within a factor of two of those for neutron irradiation. The level of agreement across all of the principal microstructure changes between ion and reactor irradiations establishes the capability of tailoring ion irradiations to emulate the reactor-irradiated microstructure.

G. S. Was; Z. Jiao; E. Beckett; A. M. Monterrosa; O. Anderoglu; B. H. Sencer; M. Hackett

2014-10-01T23:59:59.000Z

246

The HypHI project: Hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and FAIR  

E-Print Network [OSTI]

The HypHI collaboration aims to perform a precise hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and fAIR in order to study hypernuclei at extreme isospin, especially neutron rich hypernuclei to look insight hyperon-nucleon interactions in the neutron rich medium, and hypernuclear magnetic moments to investigate baryon properties in the nuclei. We are currently preparing for the first experiment with $^6$Li and $^{12}$C beams at 2 AGeV to demonstrate the feasibility of a precise hypernuclear spectroscopy by identifying $^{3}_{\\Lambda}$H, $^{4}_{\\Lambda}$H and $^{5}_{\\Lambda}$He. The first physics experiment on these hypernuclei is planned for 2009. In the present document, an overview of the HypHI project and the details of this first experiment will be discussed.

S. Bianchin; P. Achenbach; S. Ajimura; O. Borodina; T. Fukuda; J. Hoffmann; M. Kavatsyuk; K. Koch; T. Koike; N. Kurz; F. Maas; S. Minami; Y. Mizoi; T. Nagae; D. Nakajima; A. Okamura; W. Ott; B. Özel; J. Pochodzalla; C. Rappold; T. R. Saito; A. Sakaguchi; M. Sako; M. Sekimoto; H. Sugimura; T. Takahashi; H. Tamura; K. Tanida; W. Trautmann

2008-12-22T23:59:59.000Z

247

Channeling Effect in Polycrystalline Deuterium-Saturated CVD Diamond Target Bombarded by Deuterium Ion Beam  

E-Print Network [OSTI]

At the ion accelerator HELIS at the LPI, the neutron yield is investigated in DD reactions within a polycrystalline deuterium-saturated CVD diamond, during an irradiation of its surface by a deuterium ion beam with the energy less than 30 keV. The measurements of the neutron flux in the beam direction are performed in dependence on the target angle, \\b{eta}, with respect to the beam axis. These measurements are performed using a multichannel detector based on He3 counters. A significant anisotropy in neutron yield is observed, it was higher by a factor of 3 at \\b{eta}=0 compared to that at \\b{eta} = +-45{\\deg}. The possible reasons for the anisotropy, including ion channeling, are discussed.

Bagulya, A V; Negodaev, M A; Rusetskii, A S; Chubenko, A P; Ralchenko, V G; Bolshakov, A P

2014-01-01T23:59:59.000Z

248

Channeling Effect in Polycrystalline Deuterium-Saturated CVD Diamond Target Bombarded by Deuterium Ion Beam  

E-Print Network [OSTI]

At the ion accelerator HELIS at the LPI, the neutron yield is investigated in DD reactions within a polycrystalline deuterium-saturated CVD diamond, during an irradiation of its surface by a deuterium ion beam with the energy less than 30 keV. The measurements of the neutron flux in the beam direction are performed in dependence on the target angle, \\b{eta}, with respect to the beam axis. These measurements are performed using a multichannel detector based on He3 counters. A significant anisotropy in neutron yield is observed, it was higher by a factor of 3 at \\b{eta}=0 compared to that at \\b{eta} = +-45{\\deg}. The possible reasons for the anisotropy, including ion channeling, are discussed.

A. V. Bagulya; O. D. Dalkarov; M. A. Negodaev; A. S. Rusetskii; A. P. Chubenko; V. G. Ralchenko; A. P. Bolshakov

2014-09-08T23:59:59.000Z

249

Ion-beam treatment to prepare surfaces of p-CdTe films  

DOE Patents [OSTI]

A method of making a low-resistance electrical contact between a p-CdTe layer and outer contact layers by ion beam processing comprising: a) placing a CdS/CdTe device into a chamber and evacuating the chamber; b) orienting the p-CdTe side of the CdS/CdTe layer so that it faces apparatus capable of generating Ar atoms and ions of preferred energy and directionality; c) introducing Ar and igniting the area of apparatus capable of generating Ar atoms and ions of preferred energy and directionality in a manner so that during ion exposure, the source-to-substrate distance is maintained such that it is less than the mean-free path or diffusion length of the Ar atoms and ions at the vacuum pressure; d) allowing exposure of the p-CdTe side of the device to said ion beam for a period less than about 5 minutes; and e) imparting movement to the substrate to control the real uniformity of the ion-beam exposure on the p-CdTe side of the device.

Gessert, Timothy A. (Conifer, CO)

2001-01-01T23:59:59.000Z

250

Parametric coupling of lower hybrid wave with gyrating ion beam driven ion cyclotron instability in a plasma  

SciTech Connect (OSTI)

A lower hybrid wave, launched into a tokamak for supplementary heating in the presence of neutral beam turned gyrating ion beam, is seen to excite some prominent channels of parametric decay. The beam driven deuterium cyclotron mode is further destabilized by the lower hybrid pump through the nonlinear 4-wave coupling, involving higher and lower frequency lower hybrid sidebands, when ?{sub 0}/k{sub 0z}v{sub 0z}=(1??{sub LH}{sup 2}/?{sub 0}{sup 2}) , where ?{sub LH} is the lower hybrid frequency, ?{sub 0} and k{sub 0z} are the frequency and parallel wave number of the pump wave, and v{sub 0z} is the velocity of ion beam parallel to the magnetic field. The growth rate increases with parallel wave number of the ion-cyclotron mode. The pump is also susceptible to parametric upconversion into an upper sideband shifted by the frequency of the negative energy deuterium cyclotron mode. For typical parameters, the growth rate of this channel is around one fiftieth of deuterium cyclotron frequency and falls off with the transverse wave number of the mode.

Singh, Rohtash; Tripathi, V. K. [Physics Department, Indian Institute of Technology Delhi, New Delhi 110016 (India)] [Physics Department, Indian Institute of Technology Delhi, New Delhi 110016 (India)

2013-07-15T23:59:59.000Z

251

The effect of boundaries on the ion acoustic beam-plasma instability in experiment and simulation  

SciTech Connect (OSTI)

The ion acoustic beam-plasma instability is known to excite strong solitary waves near the Earth's bow shock. Using a double plasma experiment, tightly coupled with a 1-dimensional particle-in-cell simulation, the results presented here show that this instability is critically sensitive to the experimental conditions. Boundary effects, which do not have any counterpart in space or in most simulations, unavoidably excite parasitic instabilities. Potential fluctuations from these instabilities lead to an increase of the beam temperature which reduces the growth rate such that non-linear effects leading to solitary waves are less likely to be observed. Furthermore, the increased temperature modifies the range of beam velocities for which an ion acoustic beam plasma instability is observed.

Rapson, Christopher, E-mail: chris.rapson@ipp.mpg.de [Max Planck Institute for Plasma Physics, Boltzmannstr. 2, D-85748 Garching (Germany)] [Max Planck Institute for Plasma Physics, Boltzmannstr. 2, D-85748 Garching (Germany); Grulke, Olaf [Max Planck Institute for Plasma Physics, Wendelsteinstr. 1, 17491 Greifswald (Germany)] [Max Planck Institute for Plasma Physics, Wendelsteinstr. 1, 17491 Greifswald (Germany); Matyash, Konstantin [Institut für Physik, Ernst-Moritz-Arndt Universität, Domstr. 10a, 17489 Greifswald (Germany)] [Institut für Physik, Ernst-Moritz-Arndt Universität, Domstr. 10a, 17489 Greifswald (Germany); Klinger, Thomas [Max Planck Institute for Plasma Physics, Wendelsteinstr. 1, 17491 Greifswald (Germany) [Max Planck Institute for Plasma Physics, Wendelsteinstr. 1, 17491 Greifswald (Germany); Institut für Physik, Ernst-Moritz-Arndt Universität, Domstr. 10a, 17489 Greifswald (Germany)

2014-05-15T23:59:59.000Z

252

Relativistic and ponderomotive self-focusing of a laser beam in a radially inhomogeneous plasma. II. Beyond the paraxial approximation  

SciTech Connect (OSTI)

The propagation in a plasma of a high-intensity electromagnetic wave inducing both relativistic mass increase and ponderomotive expulsion of electrons is analyzed via two-dimensional simulations. The time/space evolution of the wave is modeled by an axisymmetric scalar wave equation in which the plasma frequency is an instantaneous and local function of the wave energy; the incident irradiance is assumed to be constant in time. The specific features of relativistic focusing are first discussed. The ponderomotive effect enforces the focusing process by expelling the plasma electrons, creating density bumps and sharp density gradient on the edge of the light beam; the nonlinear focusing is faster and stronger confirming the paraxial/Gaussian beam core analysis presented in Part I [Phys. Fluids B [bold 5], 3539 (1993)]. In contrast to Part I, the light is guided in a sharp-edged density channel. The influence of the radial density inhomogeneity is then examined by using both convex (basin shape) and concave (bump shape) profiles. The self-focusing threshold power is increased for concave profiles. For convex profiles, the natural refraction helps the self-focusing observation but weakens the light-guiding trend previously observed. Finally, new features characterizing wave self-focusing, such as self-steepening and light reflection, are shown.

Bonnaud, G. (Commissariat a l'Energie Atomique, Centre d'Etudes de Limeil-Valenton, 94195 Villeneuve-St.-Georges (France)); Brandi, H.S.; Manus, C.; Mainfray, G. (Service des Photons, Atomes et Molecules, Centre d'Etudes de Saclay, Bat. 522, 91191 Gif-sur-Yvette Cedex (France)); Lehner, T. (Laboratoire PMI, Ecole Polytechnique, 91128 Palaiseau (France))

1994-04-01T23:59:59.000Z

253

Photo-neutralization of Negative Ion Beam for Future Fusion Reactor  

SciTech Connect (OSTI)

An exploratory study of negative ion beam photo-neutralization for future fusion reactors is explained. A refolded Fabry-Perot cavity system is proposed, with which a 60% neutralisation efficiency could be reached with low electric power consumption. The system would make use of sophisticated optical-cavity locking systems, which have been developed recently for gravitational-wave optical detection. The ITER Neutral beam Injector is taken as an example.

Chaibi, W.; Simonin, A. [CEA, IRFM, F-13108 St Paul lez Durance (France); Blondel, C.; Cabaret, L.; Delsart, C.; Drag, C. [Laboratoire Aime Cotton, CNRS-Universite Paris XI, Bat 505 Campus d'Orsay 91405 Orsay (France)

2009-03-12T23:59:59.000Z

254

X-Ray Entangled Photon Production in Collisions of Laser Beams with Relativistic Ions  

E-Print Network [OSTI]

A method is suggested to produce, with the help of colliding laser photons with bunches of relativistic ions having two energy levels, both intense beams of monochromatic polarized X-ray fluorescence photons and significant number of X-ray entangled photons, via double Doppler transformation. Nonlinear susceptibility of the ions, the cross section and the rate of production of such photons at RHIC are estimated. Such beams of X-ray photons can be detected and applied to solve various problems, in a manner similar to the usage of optical photons.

K. A. Ispirian; M. K. Ispiryan

2010-04-02T23:59:59.000Z

255

Beam dynamics of a double-gap acceleration cell for ion implantation with multiple atomic species  

SciTech Connect (OSTI)

As a result of our work on ion implantation, we derived equations for the beam dynamics of a two-gap-resonator cavity for accelerating and bunching various ion species of varying energies with the cavity designed for one particular ion species of a given energy (the design-reference particle). A two gap structure is useful at low resonant frequencies where lumped circuit elements (inductors) can be used and the structure kept small. A single gap structure has the advantage that each gap can be independently phased to produce the desired beam dynamics behavior for various ion species and ion energies. However at low frequencies, single gap resonant structures can be large. We find that the two-gap structure, where the phase difference between gaps, for the design reference particle, is fixed at {pi} radians can give acceptable performance provided that the individual two gap cells in the entire accelerator are optimized for the ion species having the largest mass to charge ratio and having the maximum required output energy. Our equations show how to adjust the cavity phases and electric fields to obtain equivalent first-order accelerator performance for various ion species and energies. These equations allow for the effective evaluation of various accelerator concepts and can facilitate the tuning of a linac when changing energies and ion species. Extensive simulations have confirmed the efficacy of our equations. {copyright} {ital 1997 American Institute of Physics.}

Wadlinger, E.A.; Lysenko, W.P.; Rusnak, B. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Saadatmand, K. [Eaton Corporation, Semiconductor Equipment Operation, 108 Cherry Hill Drive, Beverly, Massachusetts 01915 (United States)

1997-02-01T23:59:59.000Z

256

Proceedings of the workshop on prospects for research with radioactive beams from heavy ion accelerators  

SciTech Connect (OSTI)

The SuperHILAC Users Executive Committee organized a workshop on Prospects for Research with Radioactive Beams from Heavy Ion Accelerators. The main purpose of the workshop was to bring together a diverse group of scientists who had already done experients with radioactive beams or were interested in their use in the future. The topics of the talks ranged from general nuclear physics, astrophysics, production of radioactive beams and high energy projectile fragmentation to biomedical applications. This publication contains the abstracts of the talks given at the workshop and copies of the viewgraphs as they were supplied to the editor.

Nitschke, J.M. (ed.)

1984-04-01T23:59:59.000Z

257

Ion Beam Radiation Effects in Monazite , X. Deschanels2  

E-Print Network [OSTI]

ions to simulate the consequences of alpha decay. This article describes the effects, Irradiation effects, Hardness, Density, XRD, Raman spectroscopy; Deposited energy PACS: 81.05.Je, 61.82-d, 61-19] actinides, but relatively few papers dealing with compounds incorporating both tri- and tetravalent elements

Boyer, Edmond

258

Modeling the interaction of high power ion or electron beams with solid target materials  

SciTech Connect (OSTI)

Intense energy deposition on first wall materials and other components as a result of plasma disruptions in magnetic fusion devices are expected to cause melting and vaporization of these materials. The exact amount of vaporization losses and melt layer thickness are very important to fusion reactor design and lifetime. Experiments using ion or electron beams to simulate the disruption effects have different environments than the actual disruption conditions in fusion reactors. A model has been developed to accurately simulate the beam-target interactions so that the results from such experiments can be meaningful and useful to reactor design. This model includes a two dimensional solution of the heat conduction equation with moving boundaries. It is found that the vaporization and melting of the sample strongly depends on the characteristics of the beam spatial distribution, beam diameter, and on the power-time variation of the beam.

Hassanein, A.M.

1983-11-01T23:59:59.000Z

259

Monochromatic short pulse laser produced ion beam using a compact passive magnetic device  

SciTech Connect (OSTI)

High-intensity laser accelerated protons and ions are emerging sources with complementary characteristics to those of conventional sources, namely high charge, high current, and short bunch duration, and therefore can be useful for dedicated applications. However, these beams exhibit a broadband energy spectrum when, for some experiments, monoenergetic beams are required. We present here an adaptation of conventional chicane devices in a compact form (10 cm × 20 cm) which enables selection of a specific energy interval from the broadband spectrum. This is achieved by employing magnetic fields to bend the trajectory of the laser produced proton beam through two slits in order to select the minimum and maximum beam energy. The device enables a production of a high current, short duration source with a reproducible output spectrum from short pulse laser produced charged particle beams.

Chen, S. N.; Gauthier, M.; Higginson, D. P.; Dorard, S.; Marquès, J.-R.; Fuchs, J. [LULI, École Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau (France)] [LULI, École Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau (France); Mangia, F.; Atzeni, S. [Dipartimento SBAI, Università di Roma “La Sapienza,” Roma (Italy)] [Dipartimento SBAI, Università di Roma “La Sapienza,” Roma (Italy); Riquier, R. [LULI, École Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau (France) [LULI, École Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau (France); CEA, DAM, DIF, F-91297 Arpajon (France)

2014-04-15T23:59:59.000Z

260

Summary of recent experiments on focusing of target-normal-sheath-accelerated proton beam with a stack of conducting foils  

SciTech Connect (OSTI)

We present a summary of recent experiments on focusing of laser target-normal-sheath-accelerated (TNSA) proton beam with a stack of thin conducting foils. The experiments were performed using the Phelix laser (GSI-Darmstadt) and the Titan laser, Lawrence Livermore National Laboratory. The phenomena consistent with self-collimation (or weak self-focusing) of TNSA protons were experimentally observed for the first time at the Phelix laser user facility, in a specially engineered structure ('lens') consisting of a stack of 300 thin aluminum foils separated by 50??m vacuum gaps. Follow up experiments using the Titan laser obtained results consistent with the collimation/focusing observed in the initial experiments using the Phelix. The Titan experiments employed improved, 25??m- and 50??m-gap targets and the new fine mesh diagnostic. All the experiments were carried out in a “passive environment,” i.e., no external fields were applied, and no neutralization plasma or injection of secondary charged particles was imposed. A plausible interpretation of the observed phenomena is that the combination of magnetic self-pinch forces generated by the beam current together with the simultaneous reduction of the repulsive electrostatic forces due to the conducting foils inhibits radial expansion of the beam.

Ni, P. A. [Luxim Corporation, Sunnyvale, California 94024 (United States) [Luxim Corporation, Sunnyvale, California 94024 (United States); Lawrence Berkeley National Laboratory, California 94720 (United States); Alexander, N. [General Atomics, San Diego, California 92121 (United States)] [General Atomics, San Diego, California 92121 (United States); Barnard, J. J.; Lund, S. M. [Lawrence Livermore National Laboratory, California 94550 (United States)] [Lawrence Livermore National Laboratory, California 94550 (United States)

2014-05-15T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Beam extraction and high stability operation of high current electron cyclotron resonance proton ion source  

SciTech Connect (OSTI)

A high current electron cyclotron resonance proton ion source is designed and developed for the low energy high intensity proton accelerator at Bhabha Atomic Research Centre. The plasma discharge in the ion source is stabilized by minimizing the reflected microwave power using four stub auto tuner and magnetic field. The optimization of extraction geometry is performed using PBGUNS code by varying the aperture, shape, accelerating gap, and the potential on the electrodes. While operating the source, it was found that the two layered microwave window (6 mm quartz plate and 2 mm boron nitride plate) was damaged (a fine hole was drilled) by the back-streaming electrons after continuous operation of the source for 3 h at beam current of 20–40 mA. The microwave window was then shifted from the line of sight of the back-streaming electrons and located after the water-cooled H-plane bend. In this configuration the stable operation of the high current ion source for several hours is achieved. The ion beam is extracted from the source by biasing plasma electrode, puller electrode, and ground electrode to +10 to +50 kV, ?2 to ?4 kV, and 0 kV, respectively. The total ion beam current of 30–40 mA is recorded on Faraday cup at 40 keV of beam energy at 600–1000 W of microwave power, 800–1000 G axial magnetic field and (1.2–3.9) × 10{sup ?3} mbar of neutral hydrogen gas pressure in the plasma chamber. The dependence of beam current on extraction voltage, microwave power, and gas pressure is investigated in the range of operation of the ion source.

Roychowdhury, P., E-mail: pradipr@barc.gov.in; Mishra, L.; Kewlani, H.; Mittal, K. C. [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)] [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Patil, D. S. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)] [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

2014-03-15T23:59:59.000Z

262

Demonstration of electron beam focusing by a laser-plasma lens  

E-Print Network [OSTI]

Laser-plasma technology promises a drastic reduction of the size of high energy electron accelerators. It could make free electron lasers available to a broad scientific community, and push further the limits of electron accelerators for high energy physics. Furthermore the unique femtosecond nature of the source makes it a promising tool for the study of ultra-fast phenomena. However, applications are hindered by the lack of suitable lens to transport this kind of high-current electron beams, mainly due to their divergence. Here we show that this issue can be solved by using a laser-plasma lens, in which the field gradients are five order of magnitude larger than in conventional optics. We demonstrate a reduction of the divergence by nearly a factor of three, which should allow for an efficient coupling of the beam with a conventional beam transport line.

Thaury, Cédric; Döpp, Andreas; Lehe, Remi; Lifschitz, Agustin; Phuoc, Kim Ta; Gautier, Julien; Goddet, Jean-Philippe; Tafzi, Amar; Flacco, Alessandro; Tissandier, Fabien; Sebban, Stéphane; Rousse, Antoine; Malka, Victor

2014-01-01T23:59:59.000Z

263

Method for forming metallic silicide films on silicon substrates by ion beam deposition  

SciTech Connect (OSTI)

This patent describes metallic silicide films formed on silicon substrates by contacting the substrates with a low-energy ion beam of metal ions while moderately heating the substrate. The heating of the substrate provides for the diffusion of silicon atoms through the film as it is being formed to the surface of the film for interaction with the metal ions as they contact the diffused silicon. The metallic silicide films provided by the invention are contaminant free, of uniform stoichiometry, large grain size, and exhibit low resistivity values which are of particular usefulness for integrated circuit production.

Zuhr, R.A.; Holland, O.W.

1990-03-13T23:59:59.000Z

264

Method for forming metallic silicide films on silicon substrates by ion beam deposition  

DOE Patents [OSTI]

Metallic silicide films are formed on silicon substrates by contacting the substrates with a low-energy ion beam of metal ions while moderately heating the substrate. The heating of the substrate provides for the diffusion of silicon atoms through the film as it is being formed to the surface of the film for interaction with the metal ions as they contact the diffused silicon. The metallic silicide films provided by the present invention are contaminant free, of uniform stoichiometry, large grain size, and exhibit low resistivity values which are of particular usefulness for integrated circuit production.

Zuhr, Raymond A. (Oak Ridge, TN); Holland, Orin W. (Oak Ridge, TN)

1990-01-01T23:59:59.000Z

265

Method for forming metallic silicide films on silicon substrates by ion beam deposition  

SciTech Connect (OSTI)

Metallic silicide films are formed on silicon substrates by contacting the substrates with a low-energy ion beam of metal ions while moderately heating the substrate. The heating of the substrate provides for the diffusion of silicon atoms through the film as it is being formed to the surface of the film for interaction with the metal ions as they contact the diffused silicon. The metallic silicide films provided by the present invention are contaminant free, of uniform stoichiometry, large grain size, and exhibit low resistivity values which are of particular usefulness for integrated circuit production.

Zuhr, R.A.; Holland, O.W.

1989-01-24T23:59:59.000Z

266

2D electron density profile measurement in tokamak by laser-accelerated ion-beam probe  

SciTech Connect (OSTI)

A new concept of Heavy Ion Beam Probe (HIBP) diagnostic has been proposed, of which the key is to replace the electrostatic accelerator of traditional HIBP by a laser-driven ion accelerator. Due to the large energy spread of ions, the laser-accelerated HIBP can measure the two-dimensional (2D) electron density profile of tokamak plasma. In a preliminary simulation, a 2D density profile was reconstructed with a spatial resolution of about 2 cm, and with the error below 15% in the core region. Diagnostics of 2D density fluctuation is also discussed.

Chen, Y. H.; Yang, X. Y.; Lin, C., E-mail: linchen0812@pku.edu.cn, E-mail: cjxiao@pku.edu.cn; Wang, X. G.; Xiao, C. J., E-mail: linchen0812@pku.edu.cn, E-mail: cjxiao@pku.edu.cn [State Key Lab of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Wang, L. [Institute of Physics, Chinese Academy of Sciences, P. O. Box 603, Beijing 100190 (China); Xu, M. [Center for Fusion Science of Southwestern Institute of Physics, P. O. Box 432, Chengdu 610041 (China)

2014-11-15T23:59:59.000Z

267

Ion-beam-induced damage formation in CdTe  

SciTech Connect (OSTI)

Damage formation in <111>- and <112>-oriented CdTe single crystals irradiated at room temperature and 15 K with 270 keV Ar or 730 keV Sb ions was investigated in situ using Rutherford backscattering spectroscopy (RBS) in channeling configuration. Defect profiles were calculated from the RBS spectra using the computer code DICADA and additional energy-dependent RBS measurements were performed to identify the type of defects. At both temperatures no formation of a buried amorphous layer was detected even after prolonged irradiation with several 10{sup 16} ions/cm{sup 2}. The fact that CdTe is not rendered amorphous even at 15 K suggests that the high resistance to amorphization is caused by the high ionicity of CdTe rather than thermal effects. The calculated defect profiles show the formation of a broad defect distribution that extends much deeper into the crystal than the projected range of the implanted ions at both temperatures. The post-range defects in CdTe thus do not seem to be of thermal origin either, but are instead believed to result from migration driven by the electronic energy loss.

Rischau, C. W.; Schnohr, C. S.; Wendler, E.; Wesch, W. [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany)

2011-06-01T23:59:59.000Z

268

Transport in JET H-mode Plasmas with Beam and Ion Cyclotron Heating  

SciTech Connect (OSTI)

Ion Cyclotron (IC) Range of Frequency waves and neutral beam (NB) injection are planned for heating in ITER and other future tokamaks. It is important to understand transport in plasmas with NB and IC to plan, predict, and improve transport and confinement. Transport predictions require simulations of the heating profiles, and for this, accurate modeling of the IC and NB heating is needed.

R.V. Budny, et. al.

2012-07-13T23:59:59.000Z

269

Holifield!Radioactive!Ion!Beam!Facility! Cyclotron!Driver!White!Paper!  

E-Print Network [OSTI]

Holifield!Radioactive!Ion!Beam!Facility! Cyclotron!Driver!White!Paper! ! ! ! ! prepared) driver. The quantitative details of both project cost and facility performance have changed as planning as the driver. Consequently performance is often compared to that of the electron driver concept. If we were re

270

Consequences of the ion beam irradiation on the chemical durability of Thorium Phosphate Diphosphate Kinetics study.  

E-Print Network [OSTI]

Consequences of the ion beam irradiation on the chemical durability of Thorium Phosphate of the long-term specific immobilization of actinides, Thorium Phosphate Diphosphate (-TPD), as potential-13], and thorium-actinide phosphate-diphosphate solid solutions (-Th4-xAnx(PO4)4P2O7) with associated -TPD

Paris-Sud XI, Université de

271

High Resolution Ion Mobility Spectrometry with Increased Ion Transmission: Exploring the Analytical Utility of Periodic-Focusing DC Ion Guide Drift Cells  

E-Print Network [OSTI]

Drift tube ion mobility spectrometry (IMS) is a powerful, post-ionization separation that yields structural information of ions through an ion-neutral collision cross section. The ion-neutral collision cross section is governed by the collision...

Blase, Ryan Christopher

2012-02-14T23:59:59.000Z

272

EBIT - Electronic Beam Ion Trap: N Divison experimental physics annual report 1995  

SciTech Connect (OSTI)

The multi-faceted research effort of the EBIT (Electron Beam Ion Trap) program in N-Division of the Physics and Space Technology Department at Lawrence Livermore National Laboratory (LLNL) continues to contribute significant results to the physical sciences from studies with low energy very highly charged heavy ions. The EBIT program attracts a number of collaborators from the US and abroad for the different projects. The collaborations are partly carried out through participating graduate students demonstrating the excellent educational capabilities at the LLNL EBIT facilities. Moreover, participants from Historically Black Colleges and Universities are engaged in the EBIT project. This report describes EBIT work for 1995 in atomic structure measurements and radiative transition probabilities, spectral diagnostics for laboratory and astrophysical plasmas, ion/surface interaction studies, electron-ion interactions studies, retrap and ion collisions, and instrumental development.

Schneider, D. [ed.

1996-10-01T23:59:59.000Z

273

A dynamic focusing x-ray monochromator for a wiggler beam line at the SRS of the SERC Daresbury Laboratory  

SciTech Connect (OSTI)

A Si(220) double-crystal monochromator for the energy range 10--30 keV is presented. It will be used for EXAFS as well as powder diffraction measurements. To determine the requirements for this monochromator we looked, apart from mean considerations, at the requirements dictated by EXAFS in transmission mode. For good data analyses the proper shape, amplitude, and location at the energy axis of each wiggle is required. Moreover it is essential to separate the wiggles from background and noise. For the latter a high flux through the sample is desirable, which can be achieved by horizontal focusing of the beam. For that we have chosen to bend the second crystal sagitally. The sagittal bending radius is adjustable between 50 and 0.8 m, because for different energies different sagittal radii are necessary to focus the beam on the sample. The mean meridional radius of the second crystal is fixed at 130 m, which is an optimization for 20 keV. The meridional radius of the first crystal can be tuned between 100 and 500 m. When this radius is set to 130 m the energy resolution is calculated to be 6, 3, and 35 eV for 10, 20, and 30 keV (for perfectly bent crystals). By changing the meridional radius of the first crystal, future users of this monochromator can make the trade off between resolution and intensity. Movement of the monochromator exit beam, during a scan, will occur due to the monochromator geometry, but is reduced as much as possible by using an asymmetrically cut second crystal, with an asymmetry angle of 2.5{degree}. The average exit beam movement of the monochromator for a 1-keV scan is 20 {mu}m. For 40% of the energy range (10--30 keV) the exit beam position remains within 10 {mu}m. For the second crystal no translation stage is used.

De Bruijn, D.; Van Zuylen, P. (TNO Institute of Applied Physics, P.O. Box 155, 2600 AD Delft (Netherlands)); Kruizinga, G. (Netherlands Organization for Scientific Research (NWO), P.O. Box 93138, 2509 AC Den Haag (Netherlands) State University of Utrecht, Sorbonnelaan 16, 3508 TB Utrecht (Netherlands))

1992-01-01T23:59:59.000Z

274

Statistical analysis of the ion beam production in a self magnetically insulated diode  

SciTech Connect (OSTI)

The paper presents the results of a study on shot to shot variation in energy density of an ion beam formed by a self-magnetically insulated diode with an explosive emission cathode. The experiments were carried out with the TEMP-4M accelerator operating in double-pulse mode: plasma formation occurs during the first pulse (negative polarity, 300–500 ns, 100–150 kV), and ion extraction and acceleration during the second pulse (positive polarity, 150 ns, 250–300 kV). Crucially, it was found that the standard deviation of energy density does not exceed 11%, whilst the same variation for ion current density was 20%–30%, suggesting the presence of neutrals in the beam. This idea is further supported by the fact that ion current density is only weakly dependant on the accelerating voltage and other output parameters of the accelerator (coefficient of determination < 0.3), whilst the correlation between the energy density of the beam and the output parameters is strong (coefficient of determination > 0.9). We attribute the neutral component as being due to charge exchange between accelerated ions and neutral molecules from a neutral layer near the anode surface. Implementation using a self-magnetically insulated diode with an explosive-emission cathode, having an operational lifetime of up to 10{sup 7} shots, has promising prospects for various technological applications.

Isakova, Y. I.; Pushkarev, A. I.; Khaylov, I. P. [Tomsk Polytechnic University 30 Lenin Ave., Tomsk 634050 (Russian Federation)] [Tomsk Polytechnic University 30 Lenin Ave., Tomsk 634050 (Russian Federation)

2013-09-15T23:59:59.000Z

275

Operational Experiences Tuning the ATF2 Final Focus Optics Towards Obtaining a 37nm Electron Beam IP Spot Size  

SciTech Connect (OSTI)

The primary aim of the ATF2 research accelerator is to test a scaled version of the final focus optics planned for use in next-generation linear lepton colliders. ATF2 consists of a 1.3 GeV linac, damping ring providing low-emittance electron beams (< 12pm in the vertical plane), extraction line and final focus optics. The design details of the final focus optics and implementation at ATF2 are presented elsewhere. The ATF2 accelerator is currently being commissioned, with a staged approach to achieving the design IP spot size. It is expected that as we implement more demanding optics and reduce the vertical beta function at the IP, the tuning becomes more difficult and takes longer. We present here a description of the implementation of the tuning procedures and describe operational experiences and performances.

White, Glen; /SLAC; Seryi, Andrei; /SLAC; Woodley, Mark; /SLAC; Bai, Sha; /Beijing, Inst. High Energy Phys.; Bambade, Philip; /Orsay, LAL; Renier, Yves; /Orsay, LAL; Bolzon, Benoit; /Annecy, LAPP; Kamiya, Yoshio; /Tokyo U., ICEPP; Komamiya, Sachio; /Tokyo U.; Oroku, Masahiro; /Tokyo U.; Yamaguchi, Yohei; /Tokyo U.; Yamanaka, Takashi; /Tokyo U.; Kubo, Kiyoshi; /KEK, Tsukuba; Kuroda, Shigeru; /KEK, Tsukuba; Okugi, Toshiyuki; /KEK, Tsukuba; Tauchi, Toshiaki; /KEK, Tsukuba; Marin, Eduardo; /CERN

2012-07-06T23:59:59.000Z

276

Simulation of direct plasma injection for laser ion beam acceleration with a radio frequency quadrupole  

SciTech Connect (OSTI)

The direct plasma injection scheme (DPIS) has been being studied at Institute of Modern Physics since several years ago. A C{sup 6+} beam with peak current of 13 mA, energy of 593 keV/u has been successfully achieved after acceleration with DPIS method. To understand the process of DPIS, some simulations have been done as follows. First, with the total current intensity and the relative yields of different charge states for carbon ions measured at the different distance from the target, the absolute current intensities and time-dependences for different charge states are scaled to the exit of the laser ion source in the DPIS. Then with these derived values as the input parameters, the extraction of carbon beam from the laser ion source to the radio frequency quadrupole with DPIS is simulated, which is well agreed with the experiment results.

Jin, Q. Y.; Li, Zh. M.; Liu, W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Zhao, H. Y., E-mail: zhaohy@impcas.ac.cn; Zhang, J. J.; Sha, Sh.; Zhang, Zh. L.; Zhang, X. Zh.; Sun, L. T.; Zhao, H. W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2014-07-15T23:59:59.000Z

277

Simulation and optimization of a 10 A electron gun with electrostatic compression for the electron beam ion source  

SciTech Connect (OSTI)

Increasing the current density of the electron beam in the ion trap of the Electron Beam Ion Source (EBIS) in BNL's Relativistic Heavy Ion Collider facility would confer several essential benefits. They include increasing the ions' charge states, and therefore, the ions' energy out of the Booster for NASA applications, reducing the influx of residual ions in the ion trap, lowering the average power load on the electron collector, and possibly also reducing the emittance of the extracted ion beam. Here, we discuss our findings from a computer simulation of an electron gun with electrostatic compression for electron current up to 10 A that can deliver a high-current-density electron beam for EBIS. The magnetic field in the cathode-anode gap is formed with a magnetic shield surrounding the gun electrodes and the residual magnetic field on the cathode is (5 Division-Sign 6) Gs. It was demonstrated that for optimized gun geometry within the electron beam current range of (0.5 Division-Sign 10) A the amplitude of radial beam oscillations can be maintained close to 4% of the beam radius by adjusting the injection magnetic field generated by a separate magnetic coil. Simulating the performance of the gun by varying geometrical parameters indicated that the original gun model is close to optimum and the requirements to the precision of positioning the gun elements can be easily met with conventional technology.

Pikin, A.; Beebe, E. N.; Raparia, D. [Brookhaven National Laboratory, Upton, New York 11973 (United States)

2013-03-15T23:59:59.000Z

278

Determination of the ReA Electron Beam Ion Trap electron beam radius and current density with an X-ray pinhole camera  

SciTech Connect (OSTI)

The Electron Beam Ion Trap (EBIT) of the National Superconducting Cyclotron Laboratory at Michigan State University is used as a charge booster and injector for the currently commissioned rare isotope re-accelerator facility ReA. This EBIT charge breeder is equipped with a unique superconducting magnet configuration, a combination of a solenoid and a pair of Helmholtz coils, allowing for a direct observation of the ion cloud while maintaining the advantages of a long ion trapping region. The current density of its electron beam is a key factor for efficient capture and fast charge breeding of continuously injected, short-lived isotope beams. It depends on the radius of the magnetically compressed electron beam. This radius is measured by imaging the highly charged ion cloud trapped within the electron beam with a pinhole camera, which is sensitive to X-rays emitted by the ions with photon energies between 2 keV and 10 keV. The 80%-radius of a cylindrical 800 mA electron beam with an energy of 15 keV is determined to be r{sub 80%}=(212±19)?m in a 4 T magnetic field. From this, a current density of j = (454 ± 83)A/cm{sup 2} is derived. These results are in good agreement with electron beam trajectory simulations performed with TriComp and serve as a test for future electron gun design developments.

Baumann, Thomas M., E-mail: baumannt@nscl.msu.edu; Lapierre, Alain, E-mail: lapierre@nscl.msu.edu; Kittimanapun, Kritsada; Schwarz, Stefan; Leitner, Daniela; Bollen, Georg [National Superconducting Cyclotron Laboratory (NSCL), Michigan State University (MSU), 640 S. Shaw Lane, East Lansing, Michigan, 48824 (United States)

2014-07-15T23:59:59.000Z

279

Clinical output factors for carbon-ion beams passing through polyethylene  

E-Print Network [OSTI]

Purpose: A recent study suggested that polyethylene (PE) range compensators would cause extra carbon-ion attenuation by 0.45%/cm due to limitations in water equivalence. The present study aims to assess its influence on tumor dose in carbon-ion radiotherapy. Methods: Carbon-ion radiation was modeled to be composed of primary carbon ions and secondary particles. For these components, tumor dose fraction and relative biological effectiveness (RBE) were estimated at a reference depth in the middle of spread-out Bragg peak. The PE effect was estimated for clinical carbon-ion beams and was partially tested by experiment. The two-component model was integrated into a treatment-planning system, with which the PE effect on tumor dose was investigated in two clinical cases. Results: The fluence and clinical attenuation coefficients for dose decrease per polyethylene thickness were estimated to be 0.1%-0.3%/cm and 0.2%-0.4%/cm, depending on energy and modulation of clinical carbon-ion beams. In the treatment-planning s...

Kanematsu, Nobuyuki; Ogata, Risa; Himukai, Takeshi

2013-01-01T23:59:59.000Z

280

Atomic physics with relativistic ion beams, using the Brookhaven 200 MeV linac and 1. 5 GeV Booster Synchrotron  

SciTech Connect (OSTI)

A survey of atomic physics experiments with relativistic ion beams at the Brookhaven Neutral Beam Test Facility is presented and special techniques using 150 m flight paths and precision particle and laser beam optics are described. 5 refs.

Wimmersperg, U. von; Jones, K.W.; McKenzie-Wilson, R.B.; Ward, T.E.; Snead, C.L. Jr.

1990-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Temperature dependence of ion-beam mixing in crystalline and amorphous germanium isotope multilayer structures  

SciTech Connect (OSTI)

Self-atom mixing induced by 310 keV gallium (Ga) ion implantation in crystalline and preamorphized germanium (Ge) at temperatures between 164 K and 623 K and a dose of 1?×?10{sup 15}?cm{sup ?2} is investigated using isotopic multilayer structures of alternating {sup 70}Ge and {sup nat}Ge layers grown by molecular beam epitaxy. The distribution of the implanted Ga atoms and the ion-beam induced depth-dependent self-atom mixing was determined by means of secondary ion mass spectrometry. Three different temperature regimes of self-atom mixing, i.e., low-, intermediate-, and high-temperature regimes are observed. At temperatures up to 423 K, the mixing is independent of the initial structure, whereas at 523?K, the intermixing of the preamorphized Ge structure is about twice as high as that of crystalline Ge. At 623?K, the intermixing of the initially amorphous Ge structure is strongly reduced and approaches the mixing of the crystalline material. The temperature dependence of ion-beam mixing is described by competitive amorphization and recrystallization processes.

Radek, M.; Bracht, H., E-mail: bracht@uni-muenster.de [Institute of Materials Physics, Westfälische Wilhelms-Universität Münster, 48149 Münster (Germany); Posselt, M.; Liedke, B.; Schmidt, B. [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, D-01328 Dresden (Germany); Bougeard, D. [Institut für Experimentelle und Angewandte Physik, 93040 Regensburg (Germany)

2014-01-14T23:59:59.000Z

282

Deposition of biaxially textured yttria-stabilized zirconia by ion-beam-assisted deposition.  

SciTech Connect (OSTI)

Biaxially textured yttria (8 mol %)-stabilized zirconia (YSZ) thin films were deposited on randomly oriented Hastelloy C and Stainless Steel 304 at room temperature as a buffer layer for subsequent deposition of oriented YBa{sub 2}Cu{sub 3}O{sub x} films. The 0.16-1.3 {micro}m thick YSZ films were deposited by e-beam evaporation at rates of 1.2-3.2 {angstrom}/sec. Biaxially textured films were produced with an Ar/O{sub 2} ion beam directed at the substrate during film growth. X-ray diffraction was used to study in-plane and out-of-plane orientation as a function of ion-bombardment angle, film thickness, ion-to-atom flux ratio, and substrate material. In-plane and out-of-plane average-misorientation angles on these YSZ films that were deposited by ion-beam-assisted deposition were as low as 17 and 5.4{degree}, respectively, on as-received substrates.

Chudzik, M. P.

1998-09-17T23:59:59.000Z

283

Electrostatic ion-acoustic-like instabilities in the solar wind with a backstreaming alpha particle beam  

SciTech Connect (OSTI)

Nonlinear electrostatic instabilities have been shown to occur frequently and under very different conditions in plasma with two ion beams such as the fast solar wind. These instabilities can be triggered when the phase velocity of electrostatic ion-acoustic waves propagating forward and backward relative to the interplanetary magnetic field overlaps due to the presence of a finite amplitude of circularly polarized wave. The instabilities can be triggered by waves supported by the same ion component, or by waves supported by different ion components. By assuming a beam of alpha particles moving backward relative to the external magnetic field, as observed in some events in the fast solar wind, it is shown that a very small negative drift velocity of the alpha particle beam relative to the core plasma--a few percent of the local Alfven velocity--can trigger a very rich variety of nonlinear electrostatic acousticlike instabilities. Their growth rates can be rather large and they persist for larger negative alpha particles drift velocities and temperatures.

Gomberoff, L. [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Santiago (Chile); Gomberoff, K. [Department of Physics, Technion, Haifa 32000 (Israel); Deutsch, A. [Rafael, P.O. Box 2250, Haifa 31021 (Israel)

2010-06-15T23:59:59.000Z

284

Emission Spectroscopy of Highly Charged Ions in Plasma of an Electron Beam Ion Trap  

SciTech Connect (OSTI)

The results of experimental study of magnetic dipole (M1) transitions in highly charged ions of argon (Ar9+, Ar10+, Ar13+ and Ar14+) and krypton (Kr18+ and Kr22+) are presented. The forbidden transitions of the highly charged ions in the visible and near UV range of the photon emission spectra have been measured with accuracy better than 1 ppm. Our measurements for the 'coronal lines' are the most accurate yet reported using an EBIT as a spectroscopic source of highly charged ions. These precise wavelength determinations provide a useful test and challenge for atomic structure calculations of many-electron systems.

Draganic, I. [Vinca Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia and Montenegro); Max-Planck Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Crespo Lopez-Urrutia, J.R.; Soria Orts, R.; Ullrich, J. [Max-Planck Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); DuBois, R. [University of Missouri-Rolla, Physics Building, Rolla, MO 63409-0640 (United States); Shevelko, V. [Lebedev Physical Institute, Russian Academy of Science, 117924 Moscow (Russian Federation); Fritzsche, S. [Department of Physics, University of Kassel, Heinrich-Plett-St. 40, D-34132 Kassel (Germany); Zou, Y. [Applied Ion Beam Physics Lab, Fudan University, Shanghai 200433 (China)

2004-12-01T23:59:59.000Z

285

Upgrade and benchmarking of a 4D treatment planning system for scanned ion beam therapy  

SciTech Connect (OSTI)

Purpose: Upgrade and benchmarking of a research 4D treatment planning system (4DTPS) suitable for realistic patient treatment planning and treatment simulations taking into account specific requirements for scanned ion beam therapy, i.e., modeling of dose heterogeneities due to interplay effects and range changes caused by patient motion and dynamic beam delivery. Methods: The 4DTPS integrates data interfaces to 4D computed tomography (4DCT), deformable image registration and clinically used motion monitoring devices. The authors implemented a novel data model for 4D image segmentation using Boolean mask volume datasets and developed an algorithm propagating a manually contoured reference contour dataset to all 4DCT phases. They further included detailed treatment simulation and dose reconstruction functionality, based on the irregular patient motion and the temporal structure of the beam delivery. The treatment simulation functionality was validated against experimental data from irradiation of moving radiographic films in air, 3D moving ionization chambers in a water phantom, and moving cells in a biological phantom with a scanned carbon ion beam. The performance of the program was compared to results obtained with predecessor programs. Results: The measured optical density distributions of the radiographic films were reproduced by the simulations to (-2 {+-} 12)%. Compared to earlier versions of the 4DTPS, the mean agreement improved by 2%, standard deviations were reduced by 7%. The simulated dose to the moving ionization chambers in water showed an agreement with the measured dose of (-1 {+-} 4)% for the typical beam configuration. The mean deviation of the simulated from the measured biologically effective dose determined via cell survival was (617 {+-} 538) mGy relative biological effectiveness corresponding to (10 {+-} 9)%. Conclusions: The authors developed a research 4DTPS suitable for realistic treatment planning on patient data and capable of simulating dose delivery to a moving patient geometry for scanned ion beams. The accuracy and reliability of treatment simulations improved considerably with respect to earlier versions of the 4DTPS.

Richter, D.; Schwarzkopf, A.; Trautmann, J.; Durante, M. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Abt. Biophysik, Planckstrasse 1, 64291 Darmstadt (Germany); TU Darmstadt, Hochschulstrasse 6, 64289 Darmstadt (Germany); Kraemer, M. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Abt. Biophysik, Planckstrasse 1, 64291 Darmstadt (Germany); Jaekel, O. [Clinic for Radiation Oncology, University of Heidelberg, Im Neuenheimer Feld, Heidelberg 69120 (Germany); Bert, C. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Abt. Biophysik, Planckstrasse 1, 64291 Darmstadt (Germany); Department of Radiation Oncology, University Hospital Erlangen, Universitaetsstr. 27, 91054 Erlangen (Germany)

2013-05-15T23:59:59.000Z

286

Neutral particle beam intensity controller  

DOE Patents [OSTI]

The neutral beam intensity controller is based on selected magnetic defocusing of the ion beam prior to neutralization. The defocused portion of the beam is dumped onto a beam dump disposed perpendicular to the beam axis. Selective defocusing is accomplished by means of a magnetic field generator disposed about the neutralizer so that the field is transverse to the beam axis. The magnetic field intensity is varied to provide the selected partial beam defocusing of the ions prior to neutralization. The desired focused neutral beam portion passes along the beam path through a defining aperture in the beam dump, thereby controlling the desired fraction of neutral particles transmitted to a utilization device without altering the kinetic energy level of the desired neutral particle fraction. By proper selection of the magnetic field intensity, virtually zero through 100% intensity control of the neutral beam is achieved.

Dagenhart, W.K.

1984-05-29T23:59:59.000Z

287

Absorption distribution of an optical beam focused into a turbid medium  

E-Print Network [OSTI]

the radiative transfer equation. The radiative trans- fer equation is usually too complex to solve analyt- ically and is often simplified by a diffusion approximation. The radiative transfer equation or comparable with the transport mean free path. Focusing could significantly increase the peak absorp- tion

Wang, Lihong

288

Z-petawatt driven ion beam radiography development.  

SciTech Connect (OSTI)

Laser-driven proton radiography provides electromagnetic field mapping with high spatiotemporal resolution, and has been applied to many laser-driven High Energy Density Physics (HEDP) experiments. Our report addresses key questions about the feasibility of ion radiography at the Z-Accelerator (%E2%80%9CZ%E2%80%9D), concerning laser configuration, hardware, and radiation background. Charged particle tracking revealed that radiography at Z requires GeV scale protons, which is out of reach for existing and near-future laser systems. However, it might be possible to perform proton deflectometry to detect magnetic flux compression in the fringe field region of a magnetized liner inertial fusion experiment. Experiments with the Z-Petawatt laser to enhance proton yield and energy showed an unexpected scaling with target thickness. Full-scale, 3D radiation-hydrodynamics simulations, coupled to fully explicit and kinetic 2D particle-in-cell simulations running for over 10 ps, explain the scaling by a complex interplay of laser prepulse, preplasma, and ps-scale temporal rising edge of the laser.

Schollmeier, Marius; Geissel, Matthias; Rambo, Patrick K.; Schwarz, Jens; Sefkow, Adam B.

2013-09-01T23:59:59.000Z

289

Monte Carlo calculations for reference dosimetry of electron beams with the PTW Roos and NE2571 ion chambers  

SciTech Connect (OSTI)

Purpose: To investigate recommendations for reference dosimetry of electron beams and gradient effects for the NE2571 chamber and to provide beam quality conversion factors using Monte Carlo simulations of the PTW Roos and NE2571 ion chambers. Methods: The EGSnrc code system is used to calculate the absorbed dose-to-water and the dose to the gas in fully modeled ion chambers as a function of depth in water. Electron beams are modeled using realistic accelerator simulations as well as beams modeled as collimated point sources from realistic electron beam spectra or monoenergetic electrons. Beam quality conversion factors are calculated with ratios of the doses to water and to the air in the ion chamber in electron beams and a cobalt-60 reference field. The overall ion chamber correction factor is studied using calculations of water-to-air stopping power ratios. Results: The use of an effective point of measurement shift of 1.55 mm from the front face of the PTW Roos chamber, which places the point of measurement inside the chamber cavity, minimizes the difference betweenR{sub 50}, the beam quality specifier, calculated from chamber simulations compared to that obtained using depth-dose calculations in water. A similar shift minimizes the variation of the overall ion chamber correction factor with depth to the practical range and reduces the root-mean-square deviation of a fit to calculated beam quality conversion factors at the reference depth as a function of R{sub 50}. Similarly, an upstream shift of 0.34 r{sub cav} allows a more accurate determination of R{sub 50} from NE2571 chamber calculations and reduces the variation of the overall ion chamber correction factor with depth. The determination of the gradient correction using a shift of 0.22 r{sub cav} optimizes the root-mean-square deviation of a fit to calculated beam quality conversion factors if all beams investigated are considered. However, if only clinical beams are considered, a good fit to results for beam quality conversion factors is obtained without explicitly correcting for gradient effects. The inadequacy of R{sub 50} to uniquely specify beam quality for the accurate selection of k{sub Q} factors is discussed. Systematic uncertainties in beam quality conversion factors are analyzed for the NE2571 chamber and amount to between 0.4% and 1.2% depending on assumptions used. Conclusions: The calculated beam quality conversion factors for the PTW Roos chamber obtained here are in good agreement with literature data. These results characterize the use of an NE2571 ion chamber for reference dosimetry of electron beams even in low-energy beams.

Muir, B. R., E-mail: bmuir@physics.carleton.ca; Rogers, D. W. O., E-mail: drogers@physics.carleton.ca [Physics Department, Carleton Laboratory for Radiotherapy Physics, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6 (Canada)] [Physics Department, Carleton Laboratory for Radiotherapy Physics, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6 (Canada)

2013-12-15T23:59:59.000Z

290

The beam energy dependence of collective flow in heavy ion collisions  

E-Print Network [OSTI]

The major goals of heavy ion research are to explore the phase diagram of quantum chromodynamics (QCD) and to investigate the properties of the quark gluon plasma (QGP), a new state of matter created at high temperatures and/or densities. Collective anisotropic flow is one of the most promising observables to gain insights about the properties of the system created in relativistic heavy ion reactions. The current status of the beam energy dependence of the first three Fourier coefficients of the azimuthal distribution of the produced particles $v_1$ to $v_3$ within hybrid transport plus hydrodynamics approaches are summarized.

Petersen, Hannah; Auvinen, Jussi; Bleicher, Marcus

2015-01-01T23:59:59.000Z

291

The beam energy dependence of collective flow in heavy ion collisions  

E-Print Network [OSTI]

The major goals of heavy ion research are to explore the phase diagram of quantum chromodynamics (QCD) and to investigate the properties of the quark gluon plasma (QGP), a new state of matter created at high temperatures and/or densities. Collective anisotropic flow is one of the most promising observables to gain insights about the properties of the system created in relativistic heavy ion reactions. The current status of the beam energy dependence of the first three Fourier coefficients of the azimuthal distribution of the produced particles $v_1$ to $v_3$ within hybrid transport plus hydrodynamics approaches are summarized.

Hannah Petersen; Jan Steinheimer; Jussi Auvinen; Marcus Bleicher

2015-03-11T23:59:59.000Z

292

Radiobiologic Significance of Response of Intratumor Quiescent Cells In Vivo to Accelerated Carbon Ion Beams Compared With {gamma}-Rays and Reactor Neutron Beams  

SciTech Connect (OSTI)

Purpose: To clarify the radiosensitivity of intratumor quiescent cells in vivo to accelerated carbon ion beams and reactor neutron beams. Methods and Materials: Squamous cell carcinoma VII tumor-bearing mice were continuously given 5-bromo-2'-deoxyuridine to label all intratumor proliferating cells. Next, they received accelerated carbon ion or {gamma}-ray high-dose-rate (HDR) or reduced-dose-rate (RDR) irradiation. Other tumor-bearing mice received reactor thermal or epithermal neutrons with RDR irradiation. Immediately after HDR and RDR irradiation or 12 h after HDR irradiation, the response of quiescent cells was assessed in terms of the micronucleus frequency using immunofluorescence staining for 5-bromo-2'-deoxyuridine. The response of the total (proliferating plus quiescent) tumor cells was determined from the 5-bromo-2'-deoxyuridine nontreated tumors. Results: The difference in radiosensitivity between the total and quiescent cell populations after {gamma}-ray irradiation was markedly reduced with reactor neutron beams or accelerated carbon ion beams, especially with a greater linear energy transfer (LET) value. Clearer repair in quiescent cells than in total cells through delayed assay or a decrease in the dose rate with {gamma}-ray irradiation was efficiently inhibited with carbon ion beams, especially with a greater LET. With RDR irradiation, the radiosensitivity to accelerated carbon ion beams with a greater LET was almost similar to that to reactor thermal and epithermal neutron beams. Conclusion: In terms of tumor cell-killing effect as a whole, including quiescent cells, accelerated carbon ion beams, especially with greater LET values, are very useful for suppressing the dependency on the heterogeneity within solid tumors, as well as depositing the radiation dose precisely.

Masunaga, Shin-ichiro [Particle Radiation Oncology Research Center, Research Reactor Institute, Kyoto University, Kumatori, Osaka (Japan)], E-mail: smasuna@rri.kyoto-u.ac.jp; Ando, Koichi; Uzawa, Akiko; Hirayama, Ryoichi; Furusawa, Yoshiya; Koike, Sachiko [Heavy-Ion Radiobiology Research Group, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); Sakurai, Yoshinori [Department of Physics, Faculty of Medicine, Sapporo Medical University, Sapporo (Japan); Nagata, Kenji; Suzuki, Minoru; Kashino, Genro [Particle Radiation Oncology Research Center, Research Reactor Institute, Kyoto University, Kumatori, Osaka (Japan); Kinashi, Yuko [Department of Radiation Safety and Control, Research Reactor Institute, Kyoto University, Kumatori, Osaka (Japan); Tanaka, Hiroki; Maruhashi, Akira [Department of Radiation Medical Physics, Research Reactor Institute, Kyoto University, Kumatori, Osaka (Japan); Ono, Koji [Particle Radiation Oncology Research Center, Research Reactor Institute, Kyoto University, Kumatori, Osaka (Japan)

2008-01-01T23:59:59.000Z

293

Harmonic analysis of irradiation asymmetry for cylindrical implosions driven by high-frequency rotating ion beams  

E-Print Network [OSTI]

Cylindrical implosions driven by intense heavy ions beams should be instrumental in a near future to study High Energy Density Matter. By rotating the beam by means of a high frequency wobbler, it should be possible to deposit energy in the outer layers of a cylinder, compressing the material deposited in its core. The beam temporal profile should however generate an inevitable irradiation asymmetry likely to feed the Rayleigh-Taylor instability (RTI) during the implosion phase. In this paper, we compute the Fourier components of the target irradiation in order to make the junction with previous works on RTI performed in this setting. Implementing a 1D and 2D beam models, we find these components can be expressed exactly in terms of the Fourier transform of the temporal beam profile. If $T$ is the beam duration and $\\Omega$ its rotation frequency, "magic products" $\\Omega T$ can be identified which cancel the first harmonic of the deposited density, resulting in an improved irradiation symmetry.

Bret, Antoine; Tahir, Naeem

2012-01-01T23:59:59.000Z

294

Note: Production of a mercury beam with an electron cyclotron resonance ion source  

SciTech Connect (OSTI)

An electron cyclotron resonance ion source has been utilized to produce mercury beams with intensities of 4.5 e?A of {sup 202}Hg{sup 29+} and 3.0 e?A of {sup 202}Hg{sup 31+} from natural abundance mercury metal. The production technique relies on the evaporation of liquid mercury into the source plasma vacuum region and utilizes elemental mercury instead of a volatile organic compound as the neutral feed material.

Vondrasek, R.; Pardo, R.; Scott, R. [Physics Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States)] [Physics Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States)

2013-11-15T23:59:59.000Z

295

Acceleration and Focusing Measurements in Beam-Driven Plasma Wakefields at ATF  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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296

Electrostatically focused addressable field emission array chips (AFEA's) for high-speed massively parallel maskless digital E-beam direct write lithography and scanning electron microscopy  

DOE Patents [OSTI]

Systems and methods are described for addressable field emission array (AFEA) chips. A method of operating an addressable field-emission array, includes: generating a plurality of electron beams from a pluralitly of emitters that compose the addressable field-emission array; and focusing at least one of the plurality of electron beams with an on-chip electrostatic focusing stack. The systems and methods provide advantages including the avoidance of space-charge blow-up.

Thomas, Clarence E. (Knoxville, TN); Baylor, Larry R. (Farragut, TN); Voelkl, Edgar (Oak Ridge, TN); Simpson, Michael L. (Knoxville, TN); Paulus, Michael J. (Knoxville, TN); Lowndes, Douglas H. (Knoxville, TN); Whealton, John H. (Oak Ridge, TN); Whitson, John C. (Clinton, TN); Wilgen, John B. (Oak Ridge, TN)

2002-12-24T23:59:59.000Z

297

Beta Beams for Neutrino Production Heat Deposition from Decaying Ions in Superconducting Magnets  

E-Print Network [OSTI]

This report describes studies of energy deposition in superconducting magnets from secondary ions in the "beta beam" decay ring as described in the base-line scenario of the EURISOL Beta Beam Design Study. The lattice structure proposed in the Design Study has absorber elements inserted between the superconducting magnets to protect the magnet coils. We describe an efficient and small model made to carry out the study. The specially developed options in the beam code "ACCSIM" to track largely off-momentum particles has permitted to extract the necessary information to interface the transport and interaction code "FLUKA" with the aim to calculate the heat deposition in the magnets and the absorbers. The two beta emitters 18Ne10+ and 6He2+ used for neutrino and anti-neutrino production and their daughter ions have been tracked. The absorber system proposed in the Design Study is efficient to intercept the ions decayed in the arc straight sections as foreseen, however, the continuous decay in the dipoles induce ...

Wildner, Elena; Cerutti, F

2008-01-01T23:59:59.000Z

298

Beta Beams for neutrino production: Heat deposition from decaying ions in superconducting magnets  

E-Print Network [OSTI]

This note describes studies of energy deposition in superconducting magnets from secondary ions in the “beta beam” decay ring as described in the base-line scenario of the EURISOL Beta Beam Design Study. The lattice structure proposed in the Design Study has absorber elements inserted between the superconducting magnets to protect the magnet coils. We describe an efficient and small model made to carry out the study. The specially developed options in the beam code “ACCSIM” to track largely off-momentum particles has permitted to extract the necessary information to interface the transport and interaction code “FLUKA” with the aim to calculate the heat deposition in the magnets and the absorbers. The two beta emitters 18Ne10+ and 6He2+ used for neutrino and anti-neutrino production and their daughter ions have been tracked. The absorber system proposed in the Design Study is efficient to intercept the ions decayed in the arc straight sections as foreseen, however, the continuous decay in the dipol...

Wildner, Elena; Cerutti, Francesco

299

Toroidal ripple transport of beam ions in the mega-ampere spherical tokamak  

SciTech Connect (OSTI)

The transport of injected beam ions due to toroidal magnetic field ripple in the mega-ampere spherical tokamak (MAST) is quantified using a full orbit particle tracking code, with collisional slowing-down and pitch-angle scattering by electrons and bulk ions taken into account. It is shown that the level of ripple losses is generally rather low, although it depends sensitively on the major radius of the outer midplane plasma edge; for typical values of this parameter in MAST plasmas, the reduction in beam heating power due specifically to ripple transport is less than 1%, and the ripple contribution to beam ion diffusivity is of the order of 0.1 m{sup 2} s{sup -1} or less. It is concluded that ripple effects make only a small contribution to anomalous transport rates that have been invoked to account for measured neutron rates and plasma stored energies in some MAST discharges. Delayed (non-prompt) losses are shown to occur close to the outer midplane, suggesting that banana-drift diffusion is the most likely cause of the ripple-induced losses.

McClements, K. G. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Hole, M. J. [Plasma Research Laboratory, Research School of Physical Science and Engineering, Australian National University, Canberra, ACT 0200 (Australia)

2012-07-15T23:59:59.000Z

300

Three-dimensional defect characterization : focused ion beam tomography applied to tin sulfide thin films  

E-Print Network [OSTI]

Porosity is postulated to be one of the reasons for the low efficiency of tin sulfide-based devices. This work is a preliminary investigation of the effects of two film growth parameters deposition rate and substrate ...

Youssef, Amanda

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Pure radioactive Ga ion beams provided by new laser ion source for nuclear research at ORNL  

E-Print Network [OSTI]

with 2nd, 3rd, and 4th harmonic generation capability. It can provide up to three-step, three- photon · A highly-selective laser ion source based on multi-step resonant photo-ionization has been successfully have been developed. In studies with stable isotopes, up to 40% ionization efficiency ­ the highest

302

Ion-Beam-Induced Chemical Mixing at a Nanocrystalline CeO2–Si Interface  

SciTech Connect (OSTI)

Thin films of nanocrystalline ceria deposited onto a silicon substrate have been irradiated with 3 MeV Au+ ions to a total dose of 34 displacements per atom to examine the film/substrate interfacial response upon displacement damage. Under irradiation, a band of contrast is observed to form that grows under further irradiation. Scanning and high-resolution transmission electron microscopy imaging and analysis suggest that this band of contrast is a cerium silicate phase with an approximate Ce:Si:O composition ratio of 1:1:3 in an amorphous nature. The slightly nonstoichiometric composition arises due to the loss of mobile oxygen within the cerium silicate phase under the current irradiation condition. This nonequilibrium phase is formed as a direct result of ion-beam-induced chemical mixing caused by ballistic collisions between the incoming ion and the lattice atoms. This may hold promise in ion beam engineering of cerium silicates for microelectronic applications e.g., the fabrication of blue LEDs.

Edmondson, P. D.; Young, Niel P.; Parish, Chad M.; Moll, Sandra J.; Namavar, Fereydoon; Weber, William J.; Zhang, Yanwen

2013-02-28T23:59:59.000Z

303

Ion-Beam-Induced Chemical Mixing at a Nanocrystalline CeO2 Si Interface  

SciTech Connect (OSTI)

Thin films of nanocrystalline ceria deposited onto a silicon substrate have been irradiated with 3 MeV Au+ ions to a total dose of 34 displacements per atom to examine the film/substrate interfacial response upon displacement damage. Under irradiation, a band of contrast is observed to form that grows under further irradiation. Scanning and high-resolution transmission electron microscopy imaging and analysis suggest that this band of contrast is a cerium silicate phase with an approximate Ce:Si:O composition ratio of 1:1:3 in an amorphous nature. The slightly nonstoichiometric composition arises due to the loss of mobile oxygen within the cerium silicate phase under the current irradiation condition. This nonequilibrium phase is formed as a direct result of ion-beam-induced chemical mixing caused by ballistic collisions between the incoming ion and the lattice atoms. This may hold promise in ion beam engineering of cerium silicates for microelectronic applications e.g., the fabrication of blue LEDs.

Edmondson, Dr. Philip [University of Oxford; Young, Neil P. [Department of Materials, University of Oxford, Parks Rd, Oxford, OX1 3PH, UK; Parish, Chad M [ORNL; Moll, Sandra [CEA, Saclay, France; Namavar, Fereydoon [University of Nebraska Medical Center; Weber, William J [ORNL; Zhang, Yanwen [ORNL

2013-01-01T23:59:59.000Z

304

Subcellular Spatial Correlation of Particle Traversal and Biological Response in Clinical Ion Beams  

SciTech Connect (OSTI)

Purpose: To report on the spatial correlation of physical track information (fluorescent nuclear track detectors, FNTDs) and cellular DNA damage response by using a novel hybrid detector (Cell-Fit-HD). Methods and Materials: The FNTDs were coated with a monolayer of human non-small cell lung carcinoma (A549) cells and irradiated with carbon ions (270.55 MeV u{sup ?1}, rising flank of the Bragg peak). Phosphorylated histone variant H2AX accumulating at the irradiation-induced double-strand break site was labeled (RIF). The position and direction of ion tracks in the FNTD were registered with the location of the RIF sequence as an ion track surrogate in the cell layer. Results: All RIF sequences could be related to their corresponding ion tracks, with mean deviations of 1.09 ?m and ?1.72 ?m in position and of 2.38° in slope. The mean perpendicular between ion track and RIF sequence was 1.58 ?m. The mean spacing of neighboring RIFs exhibited a regular rather than random spacing. Conclusions: Cell-Fit-HD allows for unambiguous spatial correlation studies of cell damage with respect to the intracellular ion traversal under therapeutic beam conditions.

Niklas, Martin, E-mail: m.niklas@dkfz.de [Division of Medical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg (Germany); German Cancer Consortium, National Center for Radiation Research in Oncology, Heidelberg Institute of Radiation Oncology, Heidelberg (Germany); Abdollahi, Amir [German Cancer Consortium, National Center for Radiation Research in Oncology, Heidelberg Institute of Radiation Oncology, Heidelberg (Germany); Molecular and Translational Radiation Oncology, Heidelberg Ion-Beam Therapy Center, University of Heidelberg Medical School and National Center for Tumor Diseases, German Cancer Research Center, Heidelberg (Germany); Department of Radiation Oncology and Radiation Therapy, University Hospital Heidelberg, Heidelberg (Germany); Heidelberg Ion-Beam Therapy Center, Heidelberg (Germany); Akselrod, Mark S. [Stillwater Crystal Growth Division, Landauer Inc, Stillwater, Oklahoma (United States); Debus, Jürgen [German Cancer Consortium, National Center for Radiation Research in Oncology, Heidelberg Institute of Radiation Oncology, Heidelberg (Germany); Molecular and Translational Radiation Oncology, Heidelberg Ion-Beam Therapy Center, University of Heidelberg Medical School and National Center for Tumor Diseases, German Cancer Research Center, Heidelberg (Germany); Department of Radiation Oncology and Radiation Therapy, University Hospital Heidelberg, Heidelberg (Germany); Heidelberg Ion-Beam Therapy Center, Heidelberg (Germany); Jäkel, Oliver [Division of Medical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg (Germany); German Cancer Consortium, National Center for Radiation Research in Oncology, Heidelberg Institute of Radiation Oncology, Heidelberg (Germany); Department of Radiation Oncology and Radiation Therapy, University Hospital Heidelberg, Heidelberg (Germany); Heidelberg Ion-Beam Therapy Center, Heidelberg (Germany); and others

2013-12-01T23:59:59.000Z

305

Mechanisms for covalent immobilization of horseradish peroxi-dase on ion beam treated polyethylene  

E-Print Network [OSTI]

The mechanism that provides the observed strong binding of biomolecules to polymer sur-faces modified by ion beams is investigated. The surface of polyethylene (PE) was modified by plasma immersion ion implantation with nitrogen ions. Structure changes including car-bonization and oxidation were observed in the modified surface layer of PE by Raman spec-troscopy, FTIR ATR spectroscopy, atomic force microscopy, surface energy measurement and XPS spectroscopy. An observed high surface energy of the modified polyethylene was attributed to the presence of free radicals on the surface. The surface energy decay with stor-age time after PIII treatment was explained by a decay of the free radical concentration while the concentration of oxygen-containing groups increased with storage time. Horseradish per-oxidase was covalently attached onto the modified PE surface. The enzymatic activity of co-valently attached protein remained high. A mechanism based on the covalent attachment by the reaction of protein with free r...

Kondyurin, Alexey V; Tilley, Jennifer M R; Nosworthy, Neil J; Bilek, Marcela M M; McKenzie, David R

2011-01-01T23:59:59.000Z

306

EBT2 Dosimetry of X-rays produced by the electron beam from PFMA-3, a Plasma Focus for medical applications  

E-Print Network [OSTI]

The electron beam emitted from the back of Plasma Focus devices is being studied as a radiation source for IORT (IntraOperative Radiation Therapy) applications. A Plasma Focus device is being developed to this aim, to be utilized as an X-ray source. The electron beam is driven to impinge on 50 {\\mu}m brass foil, where conversion X-rays are generated. Measurements with gafchromic film are performed to analyse the attenuation of the X-rays beam and to predict the dose given to the culture cell in radiobiological experiments to follow.

Elisa Ceccolini; Federico Rocchi; Domiziano Mostacci; Marco Sumini; Agostino Tartari

2011-12-09T23:59:59.000Z

307

EBT2 Dosimetry of X-rays produced by the electron beam from PFMA-3, a Plasma Focus for medical applications  

E-Print Network [OSTI]

The electron beam emitted from the back of Plasma Focus devices is being studied as a radiation source for IORT (IntraOperative Radiation Therapy) applications. A Plasma Focus device is being developed to this aim, to be utilized as an X-ray source. The electron beam is driven to impinge on 50 {\\mu}m brass foil, where conversion X-rays are generated. Measurements with gafchromic film are performed to analyse the attenuation of the X-rays beam and to predict the dose given to the culture cell in radiobiological experiments to follow.

Ceccolini, Elisa; Mostacci, Domiziano; Sumini, Marco; Tartari, Agostino

2011-01-01T23:59:59.000Z

308

Fast ignition when heating the central part of an inertial confinement fusion target by an ion beam  

SciTech Connect (OSTI)

We investigate the ignition and burning of a precompressed laser fusion target when it is rapidly heated by an ion beam with the formation of a temperature peak in the central part of the target. We present the results of our comprehensive numerical simulations of the problem that include the following components: (1) the target compression under the action of a profiled laser pulse, (2) the heating of the compressed target with spatially nonuniform density and temperature distributions by a beam of high-energy ions, and (3) the burning of the target with the initial spatial density distribution formed at the instant of maximum target compression and the initial spatial temperature distribution formed as a result of the compressed-target heating by an ion beam. The dependences of the threshold energies of the igniting ion beam and the thermonuclear gain on the width of the Gaussian beam ion energy spectrum have been established. The peculiarities of fast ignition by an ion beam related to the spatial distribution of parameters for the target precompressed by a laser pulse are discussed.

Gus’kov, S. Yu., E-mail: guskov@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Zmitrenko, N. V. [Russian Academy of Sciences, Keldysh Institute of Applied Mathematics (Russian Federation); Il’in, D. V.; Sherman, V. E. [St. Petersburg State Technical University (Russian Federation)

2014-11-15T23:59:59.000Z

309

Heavy ion beam probe advances from the first installation of the diagnostic on an RFP (invited)  

SciTech Connect (OSTI)

Heavy ion beam probes have been installed on a variety of toroidal devices, but the first and only application on a reversed field pinch is the diagnostic on the Madison Symmetric Torus. Simultaneous measurements of spatially localized equilibrium potential and fluctuations of density and potential, previously inaccessible in the core of the reversed field pinch (RFP), are now attainable. These measurements reflect the unique strength of the heavy ion beam probe (HIBP) diagnostic. They will help determine the characteristics and evolution of electrostatic fluctuations and their role in transport, and determine the relation of the interior electric field and flows. Many aspects of the RFP present original challenges to HIBP operation and inference of plasma quantities. The magnetic field contributes to a number of the issues: the comparable magnitudes of the toroidal and poloidal fields and edge reversal result in highly three-dimensional beam trajectories; partial generation of the magnetic field by plasma current cause it and hence the beam trajectories to vary with time; and temporal topology and amplitude changes are common. Associated complications include strong ultraviolet radiation and elevated particle losses that can alter functionality of the electrostatic systems and generate noise on the detectors. These complexities have necessitated the development of new operation and data analysis techniques: the implementation of primary and secondary beamlines, adoption of alternative beam steering methods, development of higher precision electrostatic system models, refinement of trajectory calculations and sample volume modeling, establishment of stray particle and noise reduction methods, and formulation of alternative data analysis techniques. These innovative methods and the knowledge gained with this system are likely to translate to future HIBP operation on large scale stellarators and tokamaks.

Demers, D. R.; Fimognari, P. J. [Xantho Technologies, LLC, Madison, Wisconsin 53705 (United States)

2012-10-15T23:59:59.000Z

310

Experimental validation of the dual positive and negative ion beam acceleration in the plasma propulsion with electronegative gases thruster  

SciTech Connect (OSTI)

The PEGASES (Plasma Propulsion with Electronegative Gases) thruster is a gridded ion thruster, where both positive and negative ions are accelerated to generate thrust. In this way, additional downstream neutralization by electrons is redundant. To achieve this, the thruster accelerates alternately positive and negative ions from an ion-ion plasma where the electron density is three orders of magnitude lower than the ion densities. This paper presents a first experimental study of the alternate acceleration in PEGASES, where SF{sub 6} is used as the working gas. Various electrostatic probes are used to investigate the source plasma potential and the energy, composition, and current of the extracted beams. We show here that the plasma potential control in such system is key parameter defining success of ion extraction and is sensitive to both parasitic electron current paths in the source region and deposition of sulphur containing dielectric films on the grids. In addition, large oscillations in the ion-ion plasma potential are found in the negative ion extraction phase. The oscillation occurs when the primary plasma approaches the grounded parts of the main core via sub-millimetres technological inputs. By controlling and suppressing the various undesired effects, we achieve perfect ion-ion plasma potential control with stable oscillation-free operation in the range of the available acceleration voltages (±350?V). The measured positive and negative ion currents in the beam are about 10?mA for each component at RF power of 100?W and non-optimized extraction system. Two different energy analyzers with and without magnetic electron suppression system are used to measure and compare the negative and positive ion and electron fluxes formed by the thruster. It is found that at alternate ion-ion extraction the positive and negative ion energy peaks are similar in areas and symmetrical in position with +/? ion energy corresponding to the amplitude of the applied acceleration voltage.

Rafalskyi, Dmytro, E-mail: dmytro.rafalskyi@lpp.polytechnique.fr; Popelier, Lara; Aanesland, Ane [Laboratoire de Physique des Plasmas, CNRS, Sorbonne Universités, UPMC Univ Paris 06, Univ Paris-Sud, Ecole Polytechnique, 91128 Palaiseau (France)

2014-02-07T23:59:59.000Z

311

Fabrication and electrical transport properties of binary Co-Si nanostructures prepared by focused electron beam-induced deposition  

SciTech Connect (OSTI)

CoSi-C binary alloys have been fabricated by focused electron beam-induced deposition by the simultaneous use of dicobaltoctacarbonyl, Co{sub 2}(CO){sub 8}, and neopentasilane, Si{sub 5}H{sub 12}, as precursor gases. By varying the relative flux of the precursors, alloys with variable chemical composition are obtained, as shown by energy dispersive x-ray analysis. Room temperature electrical resistivity measurements strongly indicate the formation of cobalt silicide and cobalt disilicide nanoclusters embedded in a carbonaceous matrix. Temperature-dependent electrical conductivity measurements show that the transport properties are governed by electron tunneling between neighboring CoSi or CoSi{sub 2} nanoclusters. In particular, by varying the metal content of the alloy, the electrical conductivity can be finely tuned from the insulating regime into the quasi-metallic tunneling coupling regime.

Porrati, F.; Huth, M. [Physikalisches Institut, Goethe-Universitaet, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany); Kaempken, B.; Terfort, A. [Institut fr Anorganische und Analytische Chemie, Goethe-Universitaet, Max-von-Laue-Str. 7, D-60438 Frankfurt am Main (Germany)

2013-02-07T23:59:59.000Z

312

Focused acoustic beam imaging of grain structure and local Young's modulus with Rayleigh and surface skimming longitudinal waves  

SciTech Connect (OSTI)

The interaction of a focused acoustic beam with materials generates Rayleigh surface waves (RSW) and surface skimming longitudinal waves (SSLW). Acoustic microscopic investigations have used the RSW amplitude and the velocity measurements, extensively for grain structure analysis. Although, the presence of SSLW has been recognized, it is rarely used in acoustic imaging. This paper presents an approach to perform microstructure imaging and local elastic modulus measurements by combining both RSW and SSLW. The acoustic imaging of grain structure was performed by measuring the amplitude of RSW and SSLW signal. The microstructure images obtained on the same region of the samples with RSW and SSLW are compared and the difference in the contrast observed is discussed based on the propagation characteristics of the individual surface waves. The velocity measurements are determined by two point defocus method. The surface wave velocities of RSW and SSLW of the same regions of the sample are combined and presented as average Young's modulus image.

Martin, R. W.; Sathish, S. [University of Dayton Research Institute, Structural Integrity Division 300 College Park Drive, Dayton, OH, 45469 (United States); Blodgett, M. P. [Air Force Research Lab, RXCA, Wright Patterson AFB, OH, 45433 (United States)

2013-01-25T23:59:59.000Z

313

Neutral particle beam intensity controller  

DOE Patents [OSTI]

A neutral beam intensity controller is provided for a neutral beam generator in which a neutral beam is established by accelerating ions from an ion source into a gas neutralizer. An amplitude modulated, rotating magnetic field is applied to the accelerated ion beam in the gas neutralizer to defocus the resultant neutral beam in a controlled manner to achieve intensity control of the neutral beam along the beam axis at constant beam energy. The rotating magnetic field alters the orbits of ions in the gas neutralizer before they are neutralized, thereby controlling the fraction of neutral particles transmitted out of the neutralizer along the central beam axis to a fusion device or the like. The altered path or defocused neutral particles are sprayed onto an actively cooled beam dump disposed perpendicular to the neutral beam axis and having a central open for passage of the focused beam at the central axis of the beamline. Virtually zero therough 100% intensity control is achieved by varying the magnetic field strength without altering the ion source beam intensity or its species yield.

Dagenhart, William K. (Oak Ridge, TN)

1986-01-01T23:59:59.000Z

314

Fabrication of planar quantum magnetic disk structure using electron beam lithography, reactive ion etching, and chemical mechanical polishing  

E-Print Network [OSTI]

Fabrication of planar quantum magnetic disk structure using electron beam lithography, reactive ion, Department of Electrical Engineering, University of Minnesota, Minneapolis, Minnesota 55455 Received 2 June's size and location, and reactive ion etching was used to form an SiO2 template. Nickel electroplating

315

Study of Nuclear Reactions with 11C and 15O Radioactive Ion Beams  

SciTech Connect (OSTI)

Nuclear reaction study with radioactive ion beams is one of the most exciting research topics in modern nuclear physics. The development of radioactive ion beams has allowed nuclear scientists and engineers to explore many unknown exotic nuclei far from the valley of nuclear stability, and to further our understanding of the evolution of the universe. The recently developed radioactive ion beam facility at the Lawrence Berkeley National Laboratory's 88-inch cyclotron is denoted as BEARS and provides {sup 11}C, {sup 14}O and {sup 15}O radioactive ion beams of high quality. These moderate to high intensity, proton-rich radioactive ion beams have been used to explore the properties of unstable nuclei such as {sup 12}N and {sup 15}F. In this work, the proton capture reaction on {sup 11}C has been evaluated via the indirect d({sup 11}C, {sup 12}N)n transfer reaction using the inverse kinematics method coupled with the Asymptotic Normalization Coefficient (ANC) theoretical approach. The total effective {sup 12}N {yields} {sup 11}C+p ANC is found to be (C{sub eff}{sup 12{sub N}}){sup 2} = 1.83 {+-} 0.27 fm{sup -1}. With the high {sup 11}C beam intensity available, our experiment showed excellent agreement with theoretical predictions and previous experimental studies. This study also indirectly confirmed that the {sup 11}C(p,{gamma}) reaction is a key step in producing CNO nuclei in supermassive low-metallicity stars, bypassing the slow triple alpha process. The newly developed {sup 15}O radioactive ion beam at BEARS was used to study the poorly known level widths of {sup 16}F via the p({sup 15}O,{sup 15}O)p reaction. Among the nuclei in the A=16, T=1 isobaric triad, many states in {sup 16}N and {sup 16}O have been well established, but less has been reported on {sup 16}F. Four states of {sup 16}F below 1 MeV have been identified experimentally: 0{sup -}, 1{sup -}, 2{sup -}, and 3{sup -} (E{sub x} = 0.0, 0.19, 0.42, and 0.72 MeV, respectively). Our study utilized R-matrix analysis and found that the 0- state has a level width of 23.1 {+-} 2.2 keV, and that the broader 1- state has a width of 91.1 {+-} 9.9 keV. The level width of the 2{sup -} state is found to be 3.3 {+-} 0.6 keV which is much narrower than the compiled value of 40 {+-} 30 keV, while a width of 14.1 {+-} 1.7 keV for the 3{sup -} state is in good agreement with the reported value (< 15 keV). These experimental level widths of all four levels are also in accordance with theoretical predictions using single particle shell model calculation.

Lee, Dongwon

2007-05-14T23:59:59.000Z

316

apf plasma focus: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

next round of experiments that will use pB11 fuel. Lerner, Eric J 2007-01-01 22 Enhanced Self-Focusing of an Ion Beam Pulse Propagating through a Background Plasma along a...

317

An estimate of the error caused by the elongation of the wavelength in a focused beam in free-space electromagnetic parameters measurement  

SciTech Connect (OSTI)

A pair of spot-focusing horn lens antenna is the key component in a free-space measurement system. The electromagnetic constitutive parameters of a planar sample are determined using transmitted and reflected electromagnetic beams. These parameters are obtained from the measured scattering parameters by the microwave network analyzer, thickness of the sample, and wavelength of a focused beam on the sample. Free-space techniques introduced by most papers consider the focused wavelength as the free-space wavelength. But in fact, the incident wave projected by a lens into the sample approximates a Gaussian beam, thus, there has an elongation of the wavelength in the focused beam and this elongation should be taken into consideration in dielectric and magnetic measurement. In this paper, elongation of the wavelength has been analyzed and measured. Measurement results show that the focused wavelength in the vicinity of the focus has an elongation of 1%–5% relative to the free-space wavelength. Elongation's influence on the measurement result of the permittivity and permeability has been investigated. Numerical analyses show that the elongation of the focused wavelength can cause the increase of the measured value of the permeability relative to traditionally measured value, but for the permittivity, it is affected by several parameters and may increase or decrease relative to traditionally measured value.

Zhang, Yunpeng; Li, En, E-mail: lien@uestc.edu.cn; Guo, Gaofeng; Xu, Jiadi; Wang, Chao [School of Electronic Engineering, University of Electronic Science and Technology of China, Chengdu 611731 (China)

2014-09-15T23:59:59.000Z

318

A prototype compton camera for in-vivo dosimetry of ion beam cancer irradiation  

SciTech Connect (OSTI)

Three-dimensional in-vivo dose monitoring of ion beam cancer irradiation can improve the quality of treatment. For this purpose we investigate the feasibility of imaging the single photon emissions due to nuclear reactions of projectiles with target nuclei (in-beam SPECT). A suitable imaging technique in the energy range of the emitted gamma rays is the Compton camera. A prototype based on prior simulations is currently under construction. Te system comprises two CdZnTe cross-strip detectors with steering grid and depth-of-interaction capability and one segmented LSO scintillator crystal with modified Anger light readout. We present the concept of the system including the front-end and DAQ electronics as well as first measurements. (authors)

Kormoll, T. [Technische Universitaet Dresden, OncoRay, PF 86, 013307 Dresden (Germany); Fiedler, F. [Helmholtzzentrum Dresden-Rossendorf, Inst. of Radiation Physics, PF 5103119, 013314 Dresden (Germany); Golnik, C. [Technische Universitaet Dresden, OncoRay, PF 86, 013307 Dresden (Germany); Heidel, K.; Kempe, M. [Helmholtzzentrum Dresden-Rossendorf, Inst. of Radiation Physics, PF 5103119, 013314 Dresden (Germany); Schoene, S.; Sobiella, M. [Helmholtzzentrum Dresden-Rossendorf, Inst. of Radiation Physics, PF 5103119, 013314 Dresden (Germany); Zuber, K. [Technische Universitaet Dresden, Inst. of Nuclear and Particle Physics, Zellescher Weg 19, 013069 Dresden (Germany); Enghardt, W. [Technische Universitaet Dresden, OncoRay, PF 86, 013307 Dresden (Germany); Helmholtzzentrum Dresden-Rossendorf, Inst. of Radiation Physics, PF 5103119, 013314 Dresden (Germany)

2011-07-01T23:59:59.000Z

319

Prospects for advanced electron cyclotron resonance and electron beam ion source charge breeding methods for EURISOL  

SciTech Connect (OSTI)

As the most ambitious concept of isotope separation on line (ISOL) facility, EURISOL aims at producing unprecedented intensities of post-accelerated radioactive isotopes. Charge breeding, which transforms the charge state of radioactive beams from 1+ to an n+ charge state prior to post-acceleration, is a key technology which has to overcome the following challenges: high charge states for high energies, efficiency, rapidity and purity. On the roadmap to EURISOL, a dedicated R and D is being undertaken to push forward the frontiers of the present state-of-the-art techniques which use either electron cyclotron resonance or electron beam ion sources. We describe here the guidelines of this R and D.

Delahaye, P.; Jardin, P.; Maunoury, L.; Traykov, E.; Varenne, F. [GANIL, CEA/DSM-CNRS/IN2P3, Bd. Becquerel, BP 55027, 14076 Caen Cedex 05 (France); Galata, A.; Porcellato, A. M.; Prete, G. F. [INFN-Laboratori Nazionali di Legnaro, Viale dell'Universita 2, 35020 Legnaro, Padova (Italy); Angot, J.; Lamy, T.; Sortais, P.; Thuillier, T. [LPSC Grenoble, 53, rue des Martyrs, 38026 Grenoble Cedex (France); Ban, G. [LPC Caen, 6 bd Marechal Juin, 14050 Caen Cedex (France); Celona, L.; Lunney, D. [INFN-Laboratori Nazionali del Sud, via S.Sofia 62, 95125 Catania (Italy); Choinski, J.; Gmaj, P.; Jakubowski, A.; Steckiewicz, O. [Heavy Ion Laboratory, University of Warsaw, ul. Pasteura 5a, 02 093 Warsaw (Poland); Kalvas, T. [Department of Physics, University of Jyvaeskylae, PB 35 (YFL) 40351 Jyvaeskylae (Finland); and others

2012-02-15T23:59:59.000Z

320

Rare-earth neutral metal injection into an electron beam ion trap plasma  

SciTech Connect (OSTI)

We have designed and implemented a neutral metal vapor injector on the SuperEBIT high-energy electron beam ion trap at the Lawrence Livermore National Laboratory. A horizontally directed vapor of a europium metal is created using a thermal evaporation technique. The metal vapor is then spatially collimated prior to injection into the trap. The source's form and quantity constraints are significantly reduced making plasmas out of metal with vapor pressures ?10{sup ?7} Torr at ?1000?°C more obtainable. A long pulsed or constant feed metal vapor injection method adds new flexibility by varying the timing of injection and rate of material being introduced into the trap.

Magee, E. W., E-mail: magee1@llnl.gov; Beiersdorfer, P.; Brown, G. V. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Hell, N. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Dr. Remeis-Sternwarte and ECAP, Universität Erlangen-Nürnberg, 96049 Bamberg (Germany)

2014-11-15T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Ion-Beam Synthesis of Epitaxial Au Nanocrystals in MgO. | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFunInfrared LandResponses toInvestigatingAdaptedInvestor|Heavy Ions:Beam

322

Ion-beam-induced chemical disorder in GaN. | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFunInfrared LandResponses toInvestigatingAdaptedInvestor|HeavyIon-beam-induced

323

Exchange bias in polycrystalline magnetite films made by ion-beam assisted deposition  

SciTech Connect (OSTI)

Iron oxide films were produced using ion-beam-assisted deposition, and Raman spectroscopy and x-ray diffraction indicate single-phase magnetite. However, incorporation of significant fractions of argon in the films from ion bombardment is evident from chemical analysis, and Fe/O ratios are lower than expected from pure magnetite, suggesting greater than normal disorder. Low temperature magnetometry and first-order reversal curve measurements show strong exchange bias, which likely arises from defects at grain boundaries, possibly amorphous, creating frustrated spins. Since these samples contain grains ?6?nm, a large fraction of the material consists of grain boundaries, where spins are highly disordered and reverse independently with external field.

Kaur, Maninder; Qiang, You [Department of Physics, University of Idaho, Moscow, Idaho 83844 (United States); Jiang, Weilin [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Burks, Edward C.; Liu, Kai [Department of Physics, University of California, Davis, California 95616 (United States); Namavar, Fereydoon [University of Nebraska Medical Center, Omaha, Nebraska 68198 (United States); McCloy, John S. [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 98163 (United States)

2014-11-07T23:59:59.000Z

324

Excitation of dust acoustic waves by an ion beam in a plasma cylinder with negatively charged dust grains  

SciTech Connect (OSTI)

An ion beam propagating through a plasma cylinder having negatively charged dust grains drives a low frequency electrostatic dust acoustic wave (DAW) to instability via Cerenkov interaction. The unstable wave frequencies and the growth rate increase with the relative density of negatively charged dust grains. The growth rate of the unstable mode scales to the one-third power of the beam density. The real part of the frequency of the unstable mode increases with the beam energy and scales to almost one-half power of the beam energy. The phase velocity, frequency, and wavelength results of the unstable mode are in compliance with the experimental observations.

Sharma, Suresh C. [Department of Applied Physics, Delhi Technological University (DTU), Shahbad Daulatpur, Bawana Road, Delhi-42 (India); Kaur, Daljeet [Department of Physics, Guru Teg Bahadur Institute of Technology, Rajouri Garden, New Delhi (India); Gahlot, Ajay [Department of Physics, Maharaja Surajmal Institute of Technology, Janakpuri, New Delhi (India); Sharma, Jyotsna [Department of Physics, KIIT College of Engineering, Bhondsi Gurgaon 122102 (India)

2014-10-15T23:59:59.000Z

325

Increasing the upper-limit intensity and temperature range for thermal self-focusing of a laser beam by using plasma density ramp-up  

SciTech Connect (OSTI)

This work is devoted to improving relativistic and ponderomotive thermal self-focusing of the intense laser beam in an underdense plasma. It is shown that the ponderomotive nonlinearity induces a saturation mechanism for thermal self-focusing. Therefore, in addition to the well-known lower-limit critical intensity, there is an upper-limit intensity for thermal self-focusing above which the laser beam starts to experience ponderomotive defocusing. It is indicated that the upper-limit intensity value is dependent on plasma and laser parameters such as the plasma electron temperature, plasma density, and laser spot size. Furthermore, the effect of the upward plasma density ramp profile on the thermal self-focusing is studied. Results show that by using the plasma density ramp-up, the upper-limit intensity increases and the self-focusing temperature range expands.

Bokaei, B.; Niknam, A. R., E-mail: a-niknam@sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of)

2014-03-15T23:59:59.000Z

326

TITAN's Digital RFQ Ion Beam Cooler and Buncher, Operation and Performance  

E-Print Network [OSTI]

We present a description of the Radio Frequency Quadrupole (RFQ) ion trap built as part of the TITAN facility. It consists of a gas-filled, segmented, linear Paul trap and is the first stage of the TITAN setup with the purpose of cooling and bunching radioactive ion beams delivered from ISAC-TRIUMF. This is the first such device to be driven digitally, i.e., using a high voltage ($V_{pp} = \\rm{400 \\, V}$), wide bandwidth ($0.2 < f < 1.2 \\, \\rm{MHz}$) square-wave as compared to the typical sinusoidal wave form. Results from the commissioning of the device as well as systematic studies with stable and radioactive ions are presented including efficiency measurements with stable $^{133}$Cs and radioactive $^{124, 126}$Cs. A novel and unique mode of operation of this device is also demonstrated where the cooled ion bunches are extracted in reverse mode, i.e., in the same direction as previously injected.

T. Brunner; M. J. Smith; M. Brodeur; S. Ettenauer; A. T. Gallant; V. V. Simon; A. Chaudhuri A. Lapierre; E. Mané; R. Ringle; M. C. Simon; J. A. Vaz; P. Delheij; M. Good; M. R. Pearson; J. Dilling

2012-02-07T23:59:59.000Z

327

Secondary ion collection and transport system for ion microprobe  

DOE Patents [OSTI]

A secondary ion collection and transport system, for use with an ion microprobe, which is very compact and occupies only a small working distance, thereby enabling the primary ion beam to have a short focal length and high resolution. Ions sputtered from the target surface by the primary beam's impact are collected between two arcuate members having radii of curvature and applied voltages that cause only ions within a specified energy band to be collected. The collected ions are accelerated and focused in a transport section consisting of a plurality of spaced conductive members which are coaxial with and distributed along the desired ion path. Relatively high voltages are applied to alternate transport sections to produce accelerating electric fields sufficient to transport the ions through the section to an ion mass analyzer, while lower voltages are applied to the other transport sections to focus the ions and bring their velocity to a level compatible with the analyzing apparatus.

Ward, James W. (Canoga Park, CA); Schlanger, Herbert (Simi Valley, CA); McNulty, Jr., Hugh (Santa Monica, CA); Parker, Norman W. (Camarillo, CA)

1985-01-01T23:59:59.000Z

328

Design of the channel for irradiation of materials with highly charged ion beams obtained from the mVINIS ion source  

SciTech Connect (OSTI)

The low-energy part of the TESLA Accelerator Installation comprises an electron cyclotron resonance ion source (the mVINIS ion source) and the channel for modification of materials (L3A). The L3A channel is long and has low beam transmission (30%-50%), so it is not suitable for high fluence implantations (over 10{sup 16} cm{sup -2}). Therefore, we are planning to introduce an experimental channel (L4), close to the mVINIS Ion Source, where we shall be able to achieve high beam currents on the target and, consequently, irradiation of materials to high fluences. During the ion implantation, we shall be able to measure fluence rate, achieve uniform fluence distribution by a mechanism for x and y sample movements, and control the sample temperature in the range of 0-200 deg. C.

Siljegovic, M.; Dobrosavljevic, A.; Draganic, I.; Cizmic, B.; Jelic, G. [Laboratory of Physics (010), Vinca Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia and Montenegro)

2006-03-15T23:59:59.000Z

329

Proceedings of the workshop on the science of intense radioactive ion beams  

SciTech Connect (OSTI)

This report contains the proceedings of a 2-1/2 day workshop on the Science of Intense Radioactive Ion Beams which was held at the Los Alamos National Laboratory on April 10--12, 1990. The workshop was attended by 105 people, representing 30 institutions from 10 countries. The thrust of the workshop was to develop the scientific opportunities which become possible with a new generation intense Radioactive Ion Beam (RIB) facility, currently being discussed within North America. The workshop was organized around five primary topics: (1) reaction physics; (2) nuclei far from stability/nuclear structure; (3) nuclear astrophysics; (4) atomic physics, material science, and applied research; and (5) facilities. Overview talks were presented on each of these topics, followed by 1-1/2 days of intense parallel working group sessions. The final half day of the workshop was devoted to the presentation and discussion of the working group summary reports, closing remarks and a discussion of future plans for this effort.

McClelland, J.B.; Vieira, D.J. (comps.)

1990-10-01T23:59:59.000Z

330

Introduction of the MC3-II/GP system, medium current ion implanter with enhanced multi-charge beam current  

SciTech Connect (OSTI)

The MC3-II/GP is a leading-edge single-wafer medium-current ion implanter, newly developed by SEN Corporation. It demonstrates exceptional productivity based on a high speed wafer-handling station and enhanced beam current. It covers a substantively wider energy range in order to fully meet advanced device requirements. Retaining the superior features of the MC3-II/WR, the MC3-II/GP provides a remarkable increase of multiply-charged beam current coupled with longer ion source lifetime. Another advanced feature of the MC3-II/GP is a 30 second or 14% reduction in auto beam setup time. These improvements enable a fabrication line to reduce the total number of ion implanters and dramatically reduce COO.

Koike, Masazumi; Sato, Fumiaki; Sano, Makoto; Kawatsu, Sho; Kariya, Hiroyuki; Kimura, Yasuhiko; Kudo, Tetsuya; Shiraishi, Miyuki; Shinozuka, Masamitsu; Takahashi, Yuji; Ishida, Yuji; Tsukihara, Mitsukuni; Ueno, Kazuyoshi; Sugitani, Michiro [SEN Corporation, 1501, Imazaike, Saijo, Ehime, 799-1362 (Japan)

2012-11-06T23:59:59.000Z

331

Response to “Comment on ‘Stationary self-focusing of Gaussian laser beam in relativistic thermal quantum plasma’” [Phys. Plasmas 21, 064701 (2014)  

SciTech Connect (OSTI)

Habibi and Ghamari have presented a Comment on our paper [Phys. Plasmas 20, 072703 (2013)] by examining quantum dielectric response in thermal quantum plasma. They have modeled the relativistic self-focusing of Gaussian laser beam in cold and warm quantum plasmas and reported that self-focusing length does not change in both situations. In this response, we have reached the following important conclusions about the comment itself.

Patil, S. D., E-mail: sdpatil-phy@rediffmail.com [Department of Physics, Devchand College, Arjunnagar, Kolhapur 591 269 (India); Takale, M. V. [Department of Physics, Doodhsakhar Mahavidyalaya, Bidri, Kolhapur 416 208 (India)

2014-06-15T23:59:59.000Z

332

Anomalous patterns and nearly defect-free ripples produced by bombarding silicon and germanium with a beam of gold ions  

SciTech Connect (OSTI)

We demonstrate that surface ripples with an exceptionally high degree of order can develop when germanium is bombarded with a broad beam of gold ions. In contrast, if silicon is sputtered with an Au{sup ?} beam, patches of ripples with two distinct wave vectors can emerge. These types of order can be understood if the coupling between the surface morphology and composition is taken into account.

Mollick, Safiul Alam; Ghose, Debabrata [Saha Institute of Nuclear Physics, Sector - I, Block - AF, Bidhan Nagar, Kolkata 700064 (India); Shipman, Patrick D. [Department of Mathematics, Colorado State University, Fort Collins, Colorado 80523 (United States); Mark Bradley, R. [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)

2014-01-27T23:59:59.000Z

333

Relativistic self-focusing of ultra-high intensity X-ray laser beams in warm quantum plasma with upward density profile  

SciTech Connect (OSTI)

The results of a numerical study of high-intensity X-ray laser beam interaction with warm quantum plasma (WQP) are presented. By means of an upward ramp density profile combined with quantum factors specially the Fermi velocity, we have demonstrated significant relativistic self-focusing (RSF) of a Gaussian electromagnetic beam in the WQP where the Fermi temperature term in the dielectric function is important. For this purpose, we have considered the quantum hydrodynamics model that modifies refractive index of inhomogeneous WQPs with the inclusion of quantum correction through the quantum statistical and diffraction effects in the relativistic regime. Also, to better illustration of the physical difference between warm and cold quantum plasmas and their effect on the RSF, we have derived the envelope equation governing the spot size of X-ray laser beam in Q-plasmas. In addition to the upward ramp density profile, we have found that the quantum effects would be caused much higher oscillation and better focusing of X-ray laser beam in the WQP compared to that of cold quantum case. Our computational results reveal the importance of the use of electrons density profile and Fermi speed in enhancing self-focusing of laser beam.

Habibi, M., E-mail: habibi.physics@gmail.com [Young Researchers and Elite Club, Shirvan Branch, Islamic Azad University, Shirvan (Iran, Islamic Republic of); Ghamari, F. [Young Researchers and Elite Club, Khorramabad Branch, Islamic Azad University, Khorramabad (Iran, Islamic Republic of)

2014-05-15T23:59:59.000Z

334

Ion-acoustic waves in a plasma consisting of adiabatic warm ions, nonisothermal electrons, and a weakly relativistic electron beam: Linear and higher-order nonlinear effects  

SciTech Connect (OSTI)

The nonlinear propagation of finite amplitude ion acoustic solitary waves in a plasma consisting of adiabatic warm ions, nonisothermal electrons, and a weakly relativistic electron beam is studied via a two-fluid model. A multiple scales technique is employed to investigate the nonlinear regime. The existence of the electron beam gives rise to four linear ion acoustic modes, which propagate at different phase speeds. The numerical analysis shows that the propagation speed of two of these modes may become complex-valued (i.e., waves cannot occur) under conditions which depend on values of the beam-to-background-electron density ratio {alpha}, the ion-to-free-electron temperature ratio {sigma}, and the electron beam velocity v{sub 0}; the remaining two modes remain real in all cases. The basic set of fluid equations are reduced to a Schamel-type equation and a linear inhomogeneous equation for the first and second-order potential perturbations, respectively. Stationary solutions of the coupled equations are derived using a renormalization method. Higher-order nonlinearity is thus shown to modify the solitary wave amplitude and may also deform its shape, even possibly transforming a simple pulse into a W-type curve for one of the modes. The dependence of the excitation amplitude and of the higher-order nonlinearity potential correction on the parameters {alpha}, {sigma}, and v{sub 0} is numerically investigated.

Esfandyari-Kalejahi, A. [Faculty of Science, Department of Physics, Azerbaijan University of Tarbiat Moallem, 51745-406 Tabriz (Iran, Islamic Republic of); Kourakis, I. [Center for Plasma Physics (CPP), Department of Physics and Astronomy, Queen's University Belfast, BT7 1 NN Northern Ireland (United Kingdom); Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Shukla, P. K. [Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2008-02-15T23:59:59.000Z

335

Development of Fragmented Low-Z Ion Beams for the NA61 Experiment at the CERN SPS  

E-Print Network [OSTI]

The NA61 experiment, aims to study the properties of the onset of deconfinement at low SPS energies and to find signatures of the critical point of strongly interacting matter. A broad range in T-?B phase diagram will be covered by performing an energy (13A-158AGeV/c) and system size (p+p, Be+Be, Ar+Ca, Xe+La) scan. In a first phase, fragmented ion beams of 7Be or 11C produced as secondaries with the same momentum per nucleon when the incident primary Pb-ion beam hits a thin Be target will be used. The H2 beam line that transports the beam to the experiment acts as a double spectrometer which combined with a new thin target (degrader) where fragments loose energy proportional to the square of their charge allows the separation of the wanted A/Z fragments. Thin scintillators and TOF measurement for the low energy points are used as particle identification devices. In this paper results from the first test of the fragmented ion beam done in 2010 will be presented showing that a pure Be beam can be obtained sa...

Efthymiopoulos, I; Bohl, T; Breuker, H; Calviani, M; Manglunki, D; Mataguez, S; Maury, S; Valderanis, C; Cornelis, K; Spanggaard, J; Cettour-Cave, S; Gazdzicki, M; Seyboth, P; Guber, F; Ivashkin, A

2011-01-01T23:59:59.000Z

336

A high-current electron gun for the electron beam ion trap at the National Superconducting Cyclotron Laboratory  

SciTech Connect (OSTI)

The Electron Beam Ion Trap (EBIT) in NSCL’s reaccelerator ReA uses continuous ion injection and accumulation. In order to maximize capture efficiency and minimize breeding time into high charge states, the EBIT requires a high-current/high current-density electron beam. A new electron gun insert based on a concave Ba-dispenser cathode has been designed and built to increase the current transmitted through the EBIT’s superconducting magnet. With the new insert, stable EBIT operating conditions with 0.8 A of electron beam have been established. The design of the electron gun is presented together with calculated and measured perveance data. In order to assess the experimental compression of the electron beam, a pinhole CCD camera has been set up to measure the electron beam radius. The camera observes X-rays emitted from highly charged ions, excited by the electron beam. Initial tests with this camera setup will be presented. They indicate that a current density of 640 A/cm{sup 2} has been reached when the EBIT magnet was operated at 4 T.

Schwarz, S., E-mail: schwarz@nscl.msu.edu; Baumann, T. M.; Kittimanapun, K.; Lapierre, A.; Snyder, A. [National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824 (United States)] [National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824 (United States)

2014-02-15T23:59:59.000Z

337

NEUTRALIZED TRANSPORT OF HIGH INTENSITY BEAMS E. Henestroza #  

E-Print Network [OSTI]

for specific degrees of neutralization. PLASMA NEUTRALIZATION Neutralization is essential for focusing heavy (~ 10-3 Torr). Final focus magnet Target Volumetric plasma Converging ion beam Chamber Wall at the Heavy Ion Fusion Virtual National Laboratory is exploring the performance of neutralized final focus

Gilson, Erik

338

Passive tailoring of laser-accelerated ion beam cut-off energy by using double foil assembly  

SciTech Connect (OSTI)

A double foil assembly is shown to be effective in tailoring the maximum energy produced by a laser-accelerated proton beam. The measurements compare favorably with adiabatic expansion simulations, and particle-in-cell simulations. The arrangement proposed here offers for some applications a simple and passive way to utilize simultaneously highest irradiance lasers that have best laser-to-ion conversion efficiency while avoiding the production of undesired high-energy ions.

Chen, S. N., E-mail: sophia.chen@polytechnique.edu; Brambrink, E.; Mancic, A.; Romagnani, L.; Audebert, P.; Fuchs, J., E-mail: julien.fuchs@polytechnique.fr [Laboratoire pour l'Utilisation des Lasers Intenses, UMR 7605 CNRS-CEA-École Polytechnique-Université Paris VI, Palaiseau (France); Robinson, A. P. L. [Central Laser Facility, STFC Rutherford-Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom)] [Central Laser Facility, STFC Rutherford-Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom); Antici, P. [Laboratoire pour l'Utilisation des Lasers Intenses, UMR 7605 CNRS-CEA-École Polytechnique-Université Paris VI, Palaiseau (France) [Laboratoire pour l'Utilisation des Lasers Intenses, UMR 7605 CNRS-CEA-École Polytechnique-Université Paris VI, Palaiseau (France); Dipartimento SBAI, Università di Roma « La Sapienza », Via Scarpa 14-16, 00165 Roma (Italy); INRS-Énergie et Matériaux, 1650 bd. L. Boulet, Varennes, J3X1S2 Québec (Canada); D'Humières, E. [Physics Department, MS-220, University of Nevada, Reno, Nevada 89557 (United States) [Physics Department, MS-220, University of Nevada, Reno, Nevada 89557 (United States); Centre de Physique Théorique, CNRS-Ecole Polytechnique, 91128 Palaiseau (France); University of Bordeaux—CNRS—CEA, CELIA, UMR5107, 33405 Talence (France); Gaillard, S. [Physics Department, MS-220, University of Nevada, Reno, Nevada 89557 (United States)] [Physics Department, MS-220, University of Nevada, Reno, Nevada 89557 (United States); Grismayer, T.; Mora, P. [Centre de Physique Théorique, CNRS-Ecole Polytechnique, 91128 Palaiseau (France)] [Centre de Physique Théorique, CNRS-Ecole Polytechnique, 91128 Palaiseau (France); Pépin, H. [INRS-Énergie et Matériaux, 1650 bd. L. Boulet, Varennes, J3X1S2 Québec (Canada)] [INRS-Énergie et Matériaux, 1650 bd. L. Boulet, Varennes, J3X1S2 Québec (Canada)

2014-02-15T23:59:59.000Z

339

Quantification of Dopant Concentrations in Diluted Magnetic Semiconductors using Ion Beam Techniques  

SciTech Connect (OSTI)

It has recently been demonstrated that magnetically doped TiO2 and SnO2 show ferromagnetism at room-temperature and Curie temperatures above room temperature. However, accurate knowledge of dopant concentrations is necessary to quantify magnetic moments in these materials. Rutherford Backscattering spectrometry (RBS) is one of the powerful techniques to quantify magnetic transition metal dopant concentrations in these materials. However, in some cases, the interference of RBS signals for different dopants and substrate elements in these materials makes analysis difficult. In this work, we demonstrate that particle induced x-ray emission (PIXE) can be successfully used to quantify the magnetic transition element dopants in several room temperature ferromagnetic materials synthesized using three different synthesis methods: oxygen plasma assisted molecular beam epitaxy, ion implantation and wet chemical methods.

Shutthanandan, V.; Thevuthasan, Suntharampillai; Droubay, Timothy C.; Kaspar, Tiffany C.; Punnoose, Alex; Hays, Jason; Chambers, Scott A.

2006-08-01T23:59:59.000Z

340

Design of quantum dot lattices in amorphous matrices by ion beam irradiation  

SciTech Connect (OSTI)

We report on the highly controllable self-assembly of semiconductor quantum dots and metallic nanoparticles in a solid amorphous matrix, induced by ion beam irradiation of an amorphous multilayer. We demonstrate experimentally and theoretically a possibility to tune the basic structural properties of the quantum dots in a wide range. Furthermore, the sizes, distances, and arrangement type of the quantum dots follow simple equations dependent on the irradiation and the multilayer properties. We present a Monte Carlo model for the simulation and prediction of the structural properties of the materials formed by this method. The presented results enable engineering and simple production of functional materials or simple devices interesting for applications in nanotechnology.

Buljan, M.; Bogdanovic-Radovic, I.; Karlusic, M.; Desnica, U. V.; Radic, N.; Jaksic, M.; Salamon, K.; Drazic, G.; Bernstorff, S.; Holy, V. [Rudjer Boskovic Institute, Bijenicka cesta 54, HR-10000 Zagreb (Croatia); Institute of Physics, Bijenicka cesta 46, HR-10000 Zagreb (Croatia); Jozef Stefan Institute, Jamova 39, SLO-1000 Ljubljana (Slovenia); Sincrotrone Trieste, I-34149 Basovizza (Italy); Charles University in Prague, CZ-12116 Prague (Czech Republic)

2011-10-15T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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to obtain the most current and comprehensive results.


341

Characterization of zirconia- and niobia-silica mixture coatings produced by ion-beam sputtering  

SciTech Connect (OSTI)

ZrO{sub 2}-SiO{sub 2} and Nb{sub 2}O{sub 5}-SiO{sub 2} mixture coatings as well as those of pure zirconia (ZrO{sub 2}), niobia (Nb{sub 2}O{sub 5}), and silica (SiO{sub 2}) deposited by ion-beam sputtering were investigated. Refractive-index dispersions, bandgaps, and volumetric fractions of materials in mixed coatings were analyzed from spectrophotometric data. Optical scattering, surface roughness, nanostructure, and optical resistance were also studied. Zirconia-silica mixtures experience the transition from crystalline to amorphous phase by increasing the content of SiO{sub 2}. This also results in reduced surface roughness. All niobia and silica coatings and their mixtures were amorphous. The obtained laser-induced damage thresholds in the subpicosecond range also correlates with respect to the silica content in both zirconia- and niobia-silica mixtures.

Melninkaitis, Andrius; Tolenis, Tomas; Mazule, Lina; Mirauskas, Julius; Sirutkaitis, Valdas; Mangote, Benoit; Fu Xinghai; Zerrad, Myriam; Gallais, Laurent; Commandre, Mireille; Kicas, Simonas; Drazdys, Ramutis

2011-03-20T23:59:59.000Z

342

Control of power characteristics of ion flow in plasma-etching reactor based on beam-plasma discharge  

SciTech Connect (OSTI)

It is shown that on the basis of the earlier revealed effect of generating the ion flow in the beam-plasma discharge from the discharge axis, a plasma processing reactor can be created for low-energy etching of semiconductor structures. The possibility of easily controlling the density and energy of ion flow by means of varying the potential of the discharge collector is demonstrated. The charge compensation of the ion flow incident on the nonconducting surface is implemented using the modulation of the potential of the substrate holder as well as the plasma-potential modulation.

Isaev, N. V.; Klykov, I. L.; Shustin, E. G., E-mail: shustin@ms.ire.rssi.ru [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Fryazino Branch) (Russian Federation)

2011-12-15T23:59:59.000Z

343

Source fabrication and lifetime for Li{sup +} ion beams extracted from alumino-silicate sources  

SciTech Connect (OSTI)

A space-charge-limited beam with current densities (J) exceeding 1 mA/cm{sup 2} have been measured from lithium alumino-silicate ion sources at a temperature of {approx}1275 deg. C. At higher extraction voltages, the source appears to become emission limited with J{>=} 1.5 mA/cm{sup 2}, and J increases weakly with the applied voltage. A 6.35 mm diameter source with an alumino-silicate coating, {<=}0.25 mm thick, has a measured lifetime of {approx}40 h at {approx}1275 deg. C, when pulsed at 0.05 Hz and with pulse length of {approx}6 {mu}s each. At this rate, the source lifetime was independent of the actual beam charge extracted due to the loss of neutral atoms at high temperature. The source lifetime increases with the amount of alumino-silicate coated on the emitting surface, and may also be further extended if the temperature is reduced between pulses.

Roy, Prabir K.; Greenway, Wayne G.; Kwan, Joe W. [Lawrence Berkeley National Laboratory (LBNL), One Cyclotron Road, Berkeley, California 94720 (United States)

2012-04-15T23:59:59.000Z

344

Source fabrication and lifetime for Li{sup +} ion beams extracted from alumino-silicate sources  

SciTech Connect (OSTI)

A space-charge-limited beam with current densities (J) exceeding 1 mA/cm{sup 2} have been measured from lithium alumino-silicate ion sources at a temperature of ?1275{degrees}C. At higher extraction voltages, the source appears to become emission limited with J ? 1.5 mA/cm{sup 2}, and J increases weakly with the applied voltage. A source with an alumino-silicate coating 6.35 mm in diameter and ?0.25 mm thick, has a lifetime of ?40 hours at ?1275{degrees}C, when pulsed at 0.05 Hz and with pulse length of ?6 ?s each. At this rate, the source lifetime was independent of the actual beam charge extracted due to the loss of neutral atoms at high temperature. Furthermore, the source lifetime increases with the amount of alumino-silicate coated on the emitting surface, and may also be extended if the temperature is reduced between pulses.

Greenway, W. G.; Kwan, J. W.

2012-02-10T23:59:59.000Z

345

Source fabrication and lifetime for Li+ ion beams extracted from alumino-silicate sources  

SciTech Connect (OSTI)

A space-charge-limited beam with current densities (J) exceeding 1 mA/cm{sup 2} have been measured from lithium alumino-silicate ion sources at a temperature of #24;~1275#14;{degrees} C. At higher extraction voltages, the source appears to become emission limited with J #21;{>=} 1.5 mA/cm{sup 2}, and J increases weakly with the applied voltage. A 6.35 mm diameter source with an alumino-silicate coating, {<=}#20;0.25 mm thick, has a measured lifetime of ~#24;40 hours at ~#24;1275#14;{degrees} C, when pulsed at 0.05 Hz and with pulse length of #24;~6 μs each. At this rate, the source lifetime was independent of the actual beam charge extracted due to the loss of neutral atoms at high temperature. The source lifetime increases with the amount of alumino-silicate coated on the emitting surface, and may also be further extended if the temperature is reduced between pulses.

Roy, Prabir K.; Greenway, Wayne G.; Kwan, Joe W

2012-03-05T23:59:59.000Z

346

Space-charge compensation measurements in electron cyclotron resonance ion source low energy beam transport lines with a retarding field analyzer  

SciTech Connect (OSTI)

In this paper we describe the first systematic measurement of beam neutralization (space charge compensation) in the ECR low energy transport line with a retarding field analyzer, which can be used to measure the potential of the beam. Expected trends for the space charge compensation levels such as increase with residual gas pressure, beam current, and beam density could be observed. However, the overall levels of neutralization are consistently low (<60%). The results and the processes involved for neutralizing ion beams are discussed for conditions typical for ECR injector beam lines. The results are compared to a simple theoretical beam plasma model as well as simulations.

Winklehner, D.; Leitner, D., E-mail: leitnerd@nscl.msu.edu; Cole, D.; Machicoane, G.; Tobos, L. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States)] [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States)

2014-02-15T23:59:59.000Z

347

Abstract ID: WED-AM-B3 Use of ion beam analysis techniques to characterise iron corrosion  

E-Print Network [OSTI]

Abstract ID: WED-AM-B3 Use of ion beam analysis techniques to characterise iron corrosion under 12 MeV proton irradiation on the corrosion behaviour of pure iron. Oxygen and hydrogen playing a crucial role during the corrosion process have been specifically investigated. Heavy desaerated water

Paris-Sud XI, Université de

348

Beta-induced Alfven-Acoustic Eigenmodes in NSTX and DIII-D Driven by Beam Ions  

E-Print Network [OSTI]

Beta-induced Alfv´en-Acoustic Eigenmodes in NSTX and DIII-D Driven by Beam Ions N. N. Gorelenkov´en Cascades) · BAAEmodes (Beta-induced Alfv´en- acoustic Eigenmodes) New BAAE modes (Gorelenkov- bilities: · TAE/RSAEs and (toroidicity-induced/ reversed shear AEs - Alfv´en Cascades) · BAAEmodes (Beta

349

DESIGN ISSUES OF RADIOACTIVE ION BEAM FACILITIES M. Lieuvin, SPIRAL/GANIL (DSM/CEA, IN2P3/CNRS)  

E-Print Network [OSTI]

illustration of the interest of these techniques. Nuclear reactions with secondary beams of light neutron (103-106 g/cm3) are such that nuclear reactions proceed on time scales of typically sec-min. Thus any are also asking for RIB, most often at very low energy, associated with ion traps. Table 1 summarises

Paris-Sud XI, Université de

350

Comparison of experimental data and three-dimensional simulations of ion beam neutralization from the Neutralized Transport Experiment  

E-Print Network [OSTI]

. Greenway, B. Logan, R. MacGill, D. Shuman et al., Phys. Rev. ST-Accel. Beams 7, 083501 2004 . Preformed-dimensional 3D particle-in-cell simulations. Along with detailed target images, 4D phase-space data with perveance,16 it is possible to scale the experi- ment to lower mass ions and particle energy as well

Gilson, Erik

351

Field emission from gadolinium silicide prepared by ion implantation with electron beam annealing  

SciTech Connect (OSTI)

A silicon-based field emission cathode, the rare earth silicide GdSi{sub 2} was prepared by implanting Gd ions into silicon using a metal vapor vacuum arc ion source and subsequently annealed by electron beam. For as-implanted samples, turn-on field was about 21 V/{mu}m at a current density of 1 {mu}A/cm{sup 2} and a field emission current density of 1 mA/cm{sup 2} was reached at an applied field of 34 V/{mu}m. After annealing, the turn-on field could be as low as 9 V/{mu}m and the current density of 1 mA/cm{sup 2} can be reached at an applied field of 14 V/{mu}m. X-ray diffraction with x-ray photoelectron spectroscopy analyses and atomic force microscopy were used to characterize microstructure changes of the samples. The results showed that these excellent field emission characteristics were attributed to the GdSi{sub 2} compounds formed in the samples. The field emission mechanism was discussed in terms of Fowler-Nordheim (FN) theory. It was found that FN plots could be divided into two segments obviously, and this was perhaps because of the thermal effect in the process of field emission.

Duan, H. G.; Xie, E. Q.; Ye, F. [School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China)

2007-03-15T23:59:59.000Z

352

A digitizer based compact digital spectrometer for ion beam analysis using field programmable gate arrays and various energy algorithms  

SciTech Connect (OSTI)

We report on the implementation of a compact multi-detector fully digital spectrometer and data acquisition system at a nuclear microprobe for ion beam analysis and imaging. The spectrometer design allows for system scalability with no restriction on the number of detectors. It consists of four-channel high-speed digitizer modules for detector signal acquisition and one low-speed digital-to-analog converter (DAC) module with two DAC channels and additional general purpose inputs/outputs to control ion beam scanning and data acquisition. Each digitizer module of the spectrometer provides its own Field Programmable Gate Array (FPGA) as digital signal processing unit to analyze detector signals as well as to synchronize the ion beam position in hard real-time. With the customized FPGA designs for all modules, all calculation intensive tasks are executed inside the modules, which reduces significantly the data stream to and CPU load on the control computer. To achieve an optimal energy resolution for all detector/preamplifier pulse shape characteristics, a user-definable infinite impulse response filter with high throughput for energy determination was implemented. The new spectrometer has an online data analysis feature, a compact size, and is able to process any type of detector signals such as particle induced x-ray emission, Rutherford backscattering spectrometry, or scanning transmission ion microscopy.

Jäger, Markus [Faculty of Mathematics and Computer Science, University of Leipzig, PF 100920, 04009 Leipzig (Germany)] [Faculty of Mathematics and Computer Science, University of Leipzig, PF 100920, 04009 Leipzig (Germany); Reinert, Tilo [Department of Physics, University of North Texas, 1155 Union Circle, Denton, Texas 76203 (United States)] [Department of Physics, University of North Texas, 1155 Union Circle, Denton, Texas 76203 (United States)

2013-08-15T23:59:59.000Z

353

Propagation of ion-acoustic solitons in an electron beam-superthermal plasma system with finite ion-temperature: Linear and fully nonlinear investigation  

SciTech Connect (OSTI)

The propagation of ion-acoustic (IA) solitons is studied in a plasma system, comprised of warm ions and superthermal (Kappa distributed) electrons in the presence of an electron-beam by using a hydrodynamic model. In the linear analysis, it is seen that increasing the superthermality lowers the phase speed of the IA waves. On the other hand, in a fully nonlinear investigation, the Mach number range and characteristics of IA solitons are analyzed, parametrically and numerically. It is found that the accessible region for the existence of IA solitons reduces with increasing the superthermality. However, IA solitons with both negative and positive polarities can coexist in the system. Additionally, solitary waves with both subsonic and supersonic speeds are predicted in the plasma, depending on the value of ion-temperature and the superthermality of electrons in the system. It is examined that there are upper critical values for beam parameters (i.e., density and velocity) after which, IA solitary waves could not propagate in the plasma. Furthermore, a typical interaction between IA waves and the electron-beam in the plasma is confirmed.

Saberian, E. [Department of Physics, Faculty of Sciences, Azarbaijan Shahid Madani University, 53714-161 Tabriz (Iran, Islamic Republic of); Department of Physics, Faculty of Basic Sciences, University of Neyshabur, Neyshabur (Iran, Islamic Republic of); Esfandyari-Kalejahi, A.; Rastkar-Ebrahimzadeh, A.; Afsari-Ghazi, M. [Department of Physics, Faculty of Sciences, Azarbaijan Shahid Madani University, 53714-161 Tabriz (Iran, Islamic Republic of)

2013-03-15T23:59:59.000Z

354

Reactive ion etching: Optimized diamond membrane fabrication for transmission electron microscopy  

E-Print Network [OSTI]

Commonly used preparation method for thin diamond membranes by focused ion beam (FIB) techniques results in surface damage. Here, the authors introduce an alternative method based on reactive ion etching (RIE). To compare ...

Li, Luozhou

355

Control system for 5 MW neutral beam ion source for SST1  

SciTech Connect (OSTI)

This article describes the control system for a 5 MW ion source of the NBI (neutral beam injector) for steady-state superconducting tokamak-1 (SST-1). The system uses both hardware and software solutions. It comprises a DAS (data acquisition system) and a control system. The DAS is used to read the voltage and current signals from eight filament heater power supplies and 24 discharge power supplies. The control system is used to adjust the filament heater current in order to achieve an effective control on the discharge current in the plasma box. The system consists of a VME (Verse Module Eurocard) system and C application program running on a VxWorks{sup TM} real-time operating system. A PID (proportional, integral, and differential) algorithm is used to control the filament heater current. Experiments using this system have shown that the discharge current can be controlled within 1% accuracy for a PID loop time of 20 ms. Response of the control system to the pressure variation of the gas in the chamber has also been studied and compared with the results obtained from those of an uncontrolled system. The present approach increases the flexibility of the control system. It not only eases the control of the plasma but also allows an easy changeover to various operation scenarios.

Patel, G.B.; Onali, Raja; Sharma, Vivek; Suresh, S.; Tripathi, V.; Bandyopadhyay, M.; Singh, N.P.; Thakkar, Dipal; Gupta, L.N.; Singh, M.J.; Patel, P.J.; Chakraborty, A.K.; Baruah, U.K.; Mattoo, S.K. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat, India-382428 (India)

2006-01-15T23:59:59.000Z

356

Construction of a scattering chamber for ion-beam analysis of environmental materials in undergraduate physics research  

SciTech Connect (OSTI)

We have developed a new scattering chamber for ion-beam analysis of environmental materials with the 1.1-MV Pelletron accelerator at the Union College Ion-Beam Analysis Laboratory. The chamber was constructed from a ten-inch, Conflat, multi-port cross and includes a three-axis target manipulator and target ladder assembly, an eight-inch turbo pump, an Amptek X-ray detector, and multiple charged particle detectors. Recent projects performed by our undergraduate research team include proton induced X-ray emission (PIXE) and Rutherford backscattering (RBS) analyses of atmospheric aerosols collected with a nine-stage cascade impactor in Upstate New York. We will describe the construction of the chamber and discuss the results of some commissioning experiments.

LaBrake, Scott M.; Vineyard, Michael F.; Turley, Colin F.; Moore, Robert D.; Johnson, Christopher [Department of Physics and Astronomy Union College, Schenectady, NY 12308 (United States)

2013-04-19T23:59:59.000Z

357

The Heavy Ion Fusion Virtual National Laboratory The Heavy Ion Path to Fusion Energy  

E-Print Network [OSTI]

-consistent power plant design for a multi- beam induction linac, final focus and chamber propagationThe Heavy Ion Fusion Virtual National Laboratory The Heavy Ion Path to Fusion Energy Grant Logan Director Heavy-Ion Fusion Virtual National Laboratory Presented to FESAC Workshop on Development Paths

358

Self-focusing, channel formation, and high-energy ion generation in interaction of an intense short laser pulse with a He jet  

E-Print Network [OSTI]

Self-focusing, channel formation, and high-energy ion generation in interaction of an intense short of interaction of a relativistically intense 4-TW, 400-fs laser pulse with a He gas jet. We observe a stable data, we reconstructed the axial profile of laser channel and on-axis laser intensity. The estimated

Umstadter, Donald

359

Understanding extraction and beam transport in the ISIS H{sup -} Penning surface plasma ion source  

SciTech Connect (OSTI)

The ISIS H{sup -} Penning surface plasma source has been developed to produce beam currents up to 70 mA and pulse lengths up to 1.5 ms at 50 Hz. This paper details the investigation into beam extraction and beam transport in an attempt to understand the beam emittance and to try to improve the emittance. A scintillator profile measurement technique has been developed to assess the performance of different plasma electrode apertures, extraction electrode geometries, and postextraction acceleration configurations. This work shows that the present extraction, beam transport, and postacceleration system are suboptimal and further work is required to improve it.

Faircloth, D. C.; Letchford, A. P.; Gabor, C.; Whitehead, M. O.; Wood, T.; Jolly, S.; Pozimski, J.; Savage, P.; Woods, M. [STFC/RAL, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Imperial College, London SW7 2AZ (United Kingdom)

2008-02-15T23:59:59.000Z

360

A PARALLEL-PROPAGATING ALFVENIC ION-BEAM INSTABILITY IN THE HIGH-BETA SOLAR WIND  

SciTech Connect (OSTI)

We investigate the conditions under which parallel-propagating Alfven/ion-cyclotron waves are driven unstable by an isotropic (T{sub {alpha}} = T{sub Parallel-To {alpha}}) population of alpha particles drifting parallel to the magnetic field at an average speed U{sub {alpha}} with respect to the protons. We derive an approximate analytic condition for the minimum value of U{sub {alpha}} needed to excite this instability and refine this result using numerical solutions to the hot-plasma dispersion relation. When the alpha-particle number density is {approx_equal} 5% of the proton number density and the two species have similar thermal speeds, the instability requires that {beta}{sub p} {approx}> 1, where {beta}{sub p} is the ratio of the proton pressure to the magnetic pressure. For 1 {approx}< {beta}{sub p} {approx}< 12, the minimum U{sub {alpha}} needed to excite this instability ranges from 0.7v{sub A} to 0.9v{sub A}, where v{sub A} is the Alfven speed. This threshold is smaller than the threshold of {approx_equal} 1.2v{sub A} for the parallel magnetosonic instability, which was previously thought to have the lowest threshold of the alpha-particle beam instabilities at {beta}{sub p} {approx}> 0.5. We discuss the role of the parallel Alfvenic drift instability for the evolution of the alpha-particle drift speed in the solar wind. We also analyze measurements from the Wind spacecraft's Faraday cups and show that the U{sub {alpha}} values measured in solar-wind streams with T{sub {alpha}} Almost-Equal-To T{sub Parallel-To {alpha}} are approximately bounded from above by the threshold of the parallel Alfvenic instability.

Verscharen, Daniel; Bourouaine, Sofiane; Chandran, Benjamin D. G. [Space Science Center, University of New Hampshire, Durham, NH 03824 (United States); Maruca, Bennett A., E-mail: daniel.verscharen@unh.edu, E-mail: s.bourouaine@unh.edu, E-mail: benjamin.chandran@unh.edu, E-mail: bmaruca@ssl.berkeley.edu [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States)

2013-08-10T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Dependence of ion beam current on position of mobile plate tuner in multi-frequencies microwaves electron cyclotron resonance ion source  

SciTech Connect (OSTI)

We are constructing a tandem-type electron cyclotron resonance ion source (ECRIS). The first stage of this can supply 2.45 GHz and 11-13 GHz microwaves to plasma chamber individually and simultaneously. We optimize the beam current I{sub FC} by the mobile plate tuner. The I{sub FC} is affected by the position of the mobile plate tuner in the chamber as like a circular cavity resonator. We aim to clarify the relation between the I{sub FC} and the ion saturation current in the ECRIS against the position of the mobile plate tuner. We obtained the result that the variation of the plasma density contributes largely to the variation of the I{sub FC} when we change the position of the mobile plate tuner.

Kurisu, Yosuke; Kiriyama, Ryutaro; Takenaka, Tomoya; Nozaki, Dai; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki [Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

2012-02-15T23:59:59.000Z

362

Time evolution of the luminosity of colliding heavy-ion beams in BNL Relativistic Heavy Ion Collider and CERN Large Hadron Collider  

E-Print Network [OSTI]

We have studied the time evolution of the heavy ion luminosity and bunch intensities in the Relativistic Heavy Ion Collider (RHIC), at BNL, and in the Large Hadron Collider (LHC), at CERN. First, we present measurements from a large number of RHIC stores (from Run 7), colliding 100 GeV/nucleon 197Au79+ beams without stochastic cooling. These are compared with two different calculation methods. The first is a simulation based on multi-particle tracking taking into account collisions, intrabeam scattering, radiation damping, and synchrotron and betatron motion. In the second, faster, method, a system of ordinary differential equations with terms describing the corresponding effects on emittances and bunch populations is solved numerically. Results of the tracking method agree very well with the RHIC data. With the faster method, significant discrepancies are found since the losses of particles diffusing out of the RF bucket due to intrabeam scattering are not modeled accurately enough. Finally, we use both meth...

Bruce, R; Fischer, W; Jowett, J M

2010-01-01T23:59:59.000Z

363

Sub-50 nm high aspect-ratio silicon pillars, ridges, and trenches fabricated using ultrahigh resolution electron beam lithography and reactive ion  

E-Print Network [OSTI]

resolution electron beam lithography and reactive ion etching P. B. Fischer and S. Y. Chou University of Minnesota Department of Electrical Engineering, Minneapolis, Minnesota 554~3 (Received 29 July 1992 and chlorine based reactive ion etching. These nanoscale Si features can be further reduced to 10 nm using

364

Beam-ion confinement for different injection geometries This article has been downloaded from IOPscience. Please scroll down to see the full text article.  

E-Print Network [OSTI]

energy, torque and particles, so a thorough understanding of beam behavior is crucial for plasma of contents for this issue, or go to the journal homepage for more Home Search Collections Journals About-ion energy and at high plasma temperature, suggesting that fast-ion transport by microturbulence

Heidbrink, William W.

365

Neutralized Drift Compression Experiments (NDCX) with a High Intensity Ion Beam  

E-Print Network [OSTI]

compression; plasma; neutralization; diagnostics; inductioncolumn with plasma plug, and beam diagnostics. Figure 2(a)the plasma column. 3. Experiment setup and diagnostics The

2006-01-01T23:59:59.000Z

366

Ion Source for Neutral beam injection meant for plasma and magnetic field diagnostics  

E-Print Network [OSTI]

Meant for Plasma and Magnetic Field Diagnostics a Jaakkodiagnostic neutral beam injection system for measuring plasmaplasma 5 . High proton fraction and small divergence are essential for diagnostic

Kwan, Joe W.

2008-01-01T23:59:59.000Z

367

Triple ion-beam studies of radiation damage in 9Cr2WVTa ferritic/martensitic steel  

SciTech Connect (OSTI)

To simulate radiation damage under a future Spallation Neutron Source (SNS) environment, irradiation experiments were conducted on a candidate 9Cr-2WVTa ferritic/martensitic steel using the Triple Ion Facility (TIF) at ORNL. Irradiation was conducted in single, dual, and triple ion beam modes using 3.5 MeV Fe{sup ++}, 360 keV He{sup +}, and 180 keV H{sup +} at 80, 200, and 350{degrees}C. These irradiations produced various defects comprising black dots, dislocation loops, line dislocations, and gas bubbles, which led to hardening. The largest increase in hardness, over 63 %, was observed after 50 dpa for triple beam irradiation conditions, revealing that both He and H are augmenting the hardening. Hardness increased less than 30 % after 30 dpa at 200{degrees}C by triple beams, compatible with neutron irradiation data from previous work which showed about a 30 % increase in yield strength after 27.2 dpa at 365{degrees}C. However, the very large concentrations of gas bubbles in the matrix and on lath and grain boundaries after these simulated SNS irradiations make predictions of fracture behavior from fission reactor irradiations to spallation target conditions inadvisable.

Lee, E.H.; Hunn, J.D.; Rao, G.R.; Klueh, R.L.; Mansur, L.K.

1997-11-01T23:59:59.000Z

368

Solenoid transport of a heavy ion beam for warm dense matterstudies and inertial confinement fusion  

SciTech Connect (OSTI)

From February to July 2006, I have been doing research as a guest at Lawrence Berkeley National Laboratory (LBNL), in the Heavy Ion Fusion group. This internship, which counts as one semester in my master's program in France, I was very pleased to do it in a field that I consider has the beauty of fundamental physics, and at the same time the special appeal of a quest for a long-term and environmentally-respectful energy source. During my stay at LBNL, I have been involved in three projects, all of them related to Neutralized Drift Compression Experiment (NDCX). The first one, experimental and analytical, has consisted in measuring the effects of the eddy currents induced by the pulsed magnets in the conducting plates of the source and diagnostic chambers of the Solenoid Transport Experiment (STX, which is a subset of NDCX). We have modeled the effect and run finite-element simulations that have reproduced the perturbation to the field. Then, we have modified WARP, the Particle-In-Cell code used to model the whole experiment, in order to import realistic fields including the eddy current effects and some details of each magnet. The second project has been to take part in a campaign of WARP simulations of the same experiment to understand the leakage of electrons that was observed in the experiment as a consequence to some diagnostics and the failure of the electrostatic electron trap. The simulations have shown qualitative agreement with the measured phenomena, but are still in progress. The third project, rather theoretical, has been related to the upcoming target experiment of a thin aluminum foil heated by a beam to the 1-eV range. At the beginning I helped by analyzing simulations of the hydrodynamic expansion and cooling of the heated material. But, progressively, my work turned into making estimates for the nature of the liquid/vapor two-phase flow. In particular, I have been working on criteria and models to predict the formation of droplets, their size, and their partial or total evaporation in the expanding flow.

Armijo, Julien

2006-10-01T23:59:59.000Z

369

Resolution Improvement and Pattern Generator Development for theMaskless Micro-Ion-Beam Reduction Lithography System  

SciTech Connect (OSTI)

The shrinking of IC devices has followed the Moore's Law for over three decades, which states that the density of transistors on integrated circuits will double about every two years. This great achievement is obtained via continuous advance in lithography technology. With the adoption of complicated resolution enhancement technologies, such as the phase shifting mask (PSM), the optical proximity correction (OPC), optical lithography with wavelength of 193 nm has enabled 45 nm printing by immersion method. However, this achievement comes together with the skyrocketing cost of masks, which makes the production of low volume application-specific IC (ASIC) impractical. In order to provide an economical lithography approach for low to medium volume advanced IC fabrication, a maskless ion beam lithography method, called Maskless Micro-ion-beam Reduction Lithography (MMRL), has been developed in the Lawrence Berkeley National Laboratory. The development of the prototype MMRL system has been described by Dr. Vinh Van Ngo in his Ph.D. thesis. But the resolution realized on the prototype MMRL system was far from the design expectation. In order to improve the resolution of the MMRL system, the ion optical system has been investigated. By integrating a field-free limiting aperture into the optical column, reducing the electromagnetic interference and cleaning the RF plasma, the resolution has been improved to around 50 nm. Computational analysis indicates that the MMRL system can be operated with an exposure field size of 0.25 mm and a beam half angle of 1.0 mrad on the wafer plane. Ion-ion interactions have been studied with a two-particle physics model. The results are in excellent agreement with those published by the other research groups. The charge-interaction analysis of MMRL shows that the ion-ion interactions must be reduced in order to obtain a throughput higher than 10 wafers per hour on 300-mm wafers. In addition, two different maskless lithography strategies have been studied. The dependence of the throughput with the exposure field size and the speed of the mechanical stage has been investigated. In order to perform maskless lithography, different micro-fabricated pattern generators have been developed for the MMRL system. Ion beamlet switching has been successfully demonstrated on the MMRL system. A positive bias voltage around 10 volts is sufficient to switch off the ion current on the micro-fabricated pattern generators. Some unexpected problems, such as the high-energy secondary electron radiations, have been discovered during the experimental investigation. Thermal and structural analysis indicates that the aperture displacement error induced by thermal expansion can satisfy the 3{delta} CD requirement for lithography nodes down to 25 nm. The cross-talking effect near the surface and inside the apertures of the pattern generator has been simulated in a 3-D ray-tracing code. New pattern generator design has been proposed to reduce the cross-talking effect. In order to eliminate the surface charging effect caused by the secondary electrons, a new beam-switching scheme in which the switching electrodes are immersed in the plasma has been demonstrated on a mechanically fabricated pattern generator.

Jiang, Ximan

2006-05-18T23:59:59.000Z

370

Monte-Carlo Simulation of High Harmonic Fast Wave Heating of Neutral Beam Ions and Effects on MHD Stability: Validation With Experiments  

SciTech Connect (OSTI)

Experimentally, during fast wave (FW) radio frequency (rf) heating in DIII-D L-mode discharges, strong acceleration of neutral beam (NB) deuterium beam ions has been observed. Significant effects on the n/m = 1/1 sawtooth stability are also seen. Simulations using the Monte-Carlo Hamiltonian code ORBIT-RF, coupled to the TORIC full wave code, predict beam ion tails up to a few hundred keV, in agreement with the experiment. The simulations and experiment both clearly show a much greater efficiency for 4th harmonic FW heating than for 8th harmonic heating. Simple analyses of the kinetic contribution to the ideal magnetohydrodynamic (MHD) potential energy from energetic beam ions generated by FW heating yields reasonable consistency with the observations. A more detailed analysis shows a more complicated picture, however. Other physics effects such as geometry, plasma rotation, and the presence of a free boundary, play a significant role.

Chan, V. S.; Turnbull, A. D.; Choi, M.; Chu, M. S.; Lao, L. L. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)

2006-11-30T23:59:59.000Z

371

Time evolution of the luminosity of colliding heavy-ion beams in BNL Relativistic Heavy Ion Collider and CERN Large Hadron Collider  

E-Print Network [OSTI]

We have studied the time evolution of the heavy ion luminosity and bunch intensities in the Relativistic Heavy Ion Collider (RHIC), at BNL, and in the Large Hadron Collider (LHC), at CERN. First, we present measurements from a large number of RHIC stores (from Run 7), colliding 100 GeV/nucleon Au beams without stochastic cooling. These are compared with two different calculation methods. The first is a simulation based on multi-particle tracking taking into account collisions, intrabeam scattering, radiation damping, and synchrotron and betatron motion. In the second, faster, method, a system of ordinary differential equations with terms describing the corresponding effects on emittances and bunch populations is solved numerically. Results of the tracking method agree very well with the RHIC data. With the faster method, significant discrepancies are found since the losses of particles diffusing out of the RF bucket due to intrabeam scattering are not modeled accurately enough. Finally, we use both methods to make predictions of the time evolution of the future Pb beams in the LHC at injection and collision energy. For this machine, the two methods agree well.

R. Bruce; M. Blaskiewicz; W. Fischer; J. M. Jowett

2010-09-08T23:59:59.000Z

372

Beam Energy Scaling on Ion-Induced Electron Yield from K+ Impact on Stainless Steel  

E-Print Network [OSTI]

K + Impact on Stainless Steel Michel Kireeff Covo Lawrence+ ions hit the stainless steel target with energy up to 400energies hitting stainless steel target obtained from

2006-01-01T23:59:59.000Z

373

Spectra of In-like Tungsten, $W^{25+}$, from the Shanghai permanent magnet electron beam ion trap  

E-Print Network [OSTI]

Three visible lines of M1 transitions from In-like W were recorded using the Shanghai permanent magnet electron beam ion trap. The experimental wavelengths were measured as 493.84 $\\pm$ 0.15, 226.97 $\\pm$ 0.13 and 587.63 $\\pm$ 0.23 nm (vacuum wavelengths). These results are in good agreement with theoretical predictions obtained using large-scale Relativistic Many-Body Perturbation Theory, in the form of the Flexible Atomic Code, and some explorations with the Muliconfiguration Dirac-Hartree-Fock code GRASP2K.

Li, W; Shi, Z; Fei, Z; R,; Zhao,; Brage, T; Huldt, S; Hutton, R; Zou, Y

2015-01-01T23:59:59.000Z

374

Fast six-channel pyrometer for warm-dense-matter experiments with intense heavy-ion beams  

SciTech Connect (OSTI)

This paper describes a fast multi-channel radiation pyrometer that was developed for warmdense-matter experiments with intense heavy ion beams at Gesellschaft fur Schwerionenforschung mbH (GSI). The pyrometer is capable of measuring of brightness temperatures from 2000 K to 50000 K, at 6 wavelengths in visible and near-infrared parts of spectrum, with 5 nanosecond temporal resolution and several micrometers spatial resolution. The pyrometer's spectral discrimination technique is based on interference filters, which act as filters and mirrors to allow for simultaneous spectral discrimination of the same ray at multiple wavelengths.

Ni, P.A.; Kulish, M.I.; Mintsev, V.; Nikolaev, D.N.; Ternovoi, V.Ya.; Hoffmann, D.H.H.; Udrea, S.; Tahir, N.A.; Varentsov, D.; Hug, A.

2008-12-01T23:59:59.000Z

375

Progress on Plasma Lens Experiments at the Final Focus Test Beam* P. Kwok*, P. Chen13,D. Cline2,7N.Barletta4, S. Berridge14,W. Bugg14,C. Bula'O, S. Chatt~padhyay~,W. Craddock13,  

E-Print Network [OSTI]

Progress on Plasma Lens Experiments at the Final Focus Test Beam* P. Kwok*, P. Chen13,D. Cline2,7N. Abstract The proposal to perform a series of plasma lens experiments at the Final Focus Test Beam at SLAC as the plasma source, and study on focused beam size measurement techniques. Most importantly, the effects

McDonald, Kirk

376

Ion-radical synergy in HfO{sub 2} etching studied with a XeF{sub 2}/Ar{sup +} beam setup  

SciTech Connect (OSTI)

To gain more insight into fundamental aspects of the etching behavior of Hf-based high-k materials in plasma etch reactors, HfO{sub 2} films were etched in a multiple-beam setup consisting of a low energy Ar{sup +} ion beam and a XeF{sub 2} radical beam. The etch rate and etch products were monitored by real-time ellipsometry and mass spectrometry, respectively. Although etching of HfO{sub 2} in XeF{sub 2}/Ar{sup +} chemistry is mainly a physical effect, an unambiguous proof of the ion-radical synergistic effect for the etching of HfO{sub 2} is presented. The etch yield for 400 eV Ar{sup +} ions at a substrate temperature of 300 deg. C was 0.3 atoms/ion for Ar{sup +} sputtering and increased to 2 atoms/ion when XeF{sub 2} was also supplied. The etch yield proved to follow the common square root of ion energy dependence both for pure sputtering and radical enhanced etching, with a threshold energy at room temperature of 69{+-}17 eV for Ar{sup +} ions and 54{+-}14 eV for Ar{sup +} ions with XeF{sub 2}.

Gevers, P. M.; Beijerinck, H. C. W.; Sanden, M. C. M. van de; Kessels, W. M. M. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

2008-04-15T23:59:59.000Z

377

OPERATION STATUS OF HIGH INTENSITY ION BEAMS AT GANIL F. Chautard, G. Sncal, GANIL, Caen, France  

E-Print Network [OSTI]

. · A high-energy experiment. · An auxiliary experiments sharing the CSS2 beam · Additionally, the cyclotron, Venice, Italy 54 Circular Accelerators in2p3-00396700,version1-29Jul2010 Author manuscript, published

Paris-Sud XI, Université de

378

Neutralization of space charge on high-current low-energy ion beam by low-energy electrons supplied from silicon based field emitter arrays  

SciTech Connect (OSTI)

Neutralization of space charge on a high-current and low-energy ion beam was attempted to reduce the divergence with an aid of low-energy electrons supplied from silicon based field emitter arrays (Si-FEAs). An argon ion beam with the energy of 500 eV and the current of 0.25 mA was produced by a microwave ion source. The initial beam divergence and the emittance were measured at the entrance of the analysis chamber in order to estimate the intrinsic factors for beam divergence. The current density distribution of the beam after transport of 730 mm was measured by a movable Faraday cup, with and without electron supply from Si-FEAs. A similar experiment was performed with tungsten filaments as an electron source. The results indicated that the electron supply from FEA had almost the same effect as the thermionic filament, and it was confirmed that both electron sources can neutralize the ion beam.

Gotoh, Yasuhito; Tsuji, Hiroshi; Taguchi, Shuhei; Ikeda, Keita; Kitagawa, Takayuki; Ishikawa, Junzo; Sakai, Shigeki [Dept. of Electron. Sci. Eng., Kyoto Univ. Kyotodaigaku-Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Dept. of Electron. Information Eng., Chubu Univ., 1200, Matsumoto-cho, Kasugai, Aichi 487-8501 (Japan); Nissin Ion Equipment Co., Ltd., 575 Kuze-Tonoshiro-cho, Minami-ku, Kyoto 601-8502 (Japan)

2012-11-06T23:59:59.000Z

379

Trace element content and magnetic properties of commercial HOPG samples studied by ion beam microscopy and SQUID magnetometry  

SciTech Connect (OSTI)

In this study, the impurity concentration and magnetic response of nine highly oriented pyrolytic graphite (HOPG) samples with different grades and from different providers were determined using ion beam microscopy and SQUID magnetometry. Apart from sideface contaminations in the as-received state, bulk contamination of the samples in most cases consists of disk-shaped micron-sized particles made of Ti and V with an additional Fe contamination around the grain perimeter. The saturation magnetization typically increases with Fe concentration, however, there is no simple correlation between Fe content and magnetic moment. The saturation magnetization of one, respectively six, out of nine samples clearly exceeds the maximum contribution from pure Fe or Fe{sub 3}C. For most samples the temperature dependence of the remanence decreases linearly with T – a dependence found previously for defect-induced magnetism (DIM) in HOPG. We conclude that apart from magnetic impurities, additional contribution to the ferromagnetic magnetization exists in pristine HOPG in agreement with previous studies. A comparative study between the results of ion beam microscopy and the commonly used EDX analysis shows clearly that EDX is not a reliable method for quantitative trace elemental analysis in graphite, clarifying weaknesses and discrepancies in the element concentrations given in the recent literature.

Spemann, D., E-mail: spemann@uni-leipzig.de; Esquinazi, P., E-mail: esquin@physik.uni-leipzig.de; Setzer, A.; Böhlmann, W. [Institute for Experimental Physics II, Universität Leipzig, Linnéstr. 5, 04103 Leipzig (Germany)

2014-10-15T23:59:59.000Z

380

MONO1001 : A source for singly charged ions applied to the production of multicharged fullerene beams  

E-Print Network [OSTI]

(from pure C60 and C70 powder) will be shown and the influence of several source parameters (HF-power, support gas, gas pressure, ...) will be discussed specifying the conditions necessary for an optimum ion

Boyer, Edmond

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Offline trapping of $^{221}$Fr in a magneto-optical trap from implantation of an $^{225}$Ac ion beam  

E-Print Network [OSTI]

We demonstrate a new technique to prepare an offline source of francium for trapping in a magneto-optical trap. Implanting a radioactive beam of $^{225}$Ac, $t_{1/2} = 9.920(3)$ days, in a foil, allows use of the decay products, i.e.$^{221}$Fr, $t_{1/2} = 288.0(4)$ s. $^{221}$Fr is ejected from the foil by the $\\alpha$ decay of $^{225}$Ac. This technique is compatible with the online accumulation of a laser-cooled atomic francium sample for a series of planned parity non-conservation measurements at TRIUMF. We obtain a 34% release efficiency for $^{221}$Fr from the recoil source based on particle detector measurements. We find that laser cooling operation with the source is $8^{+10}_{-5}$ times less efficient than from a mass-separated ion beam of $^{221}$Fr in the current geometry. While the flux of this source is two to three orders of magnitude lower than typical francium beams from ISOL facilities, the source provides a longer-term supply of francium for offline studies.

M. Tandecki; J. Zhang; S. Aubin; J. A. Behr; R. Collister; E. Gomez; G. Gwinner; H. Heggen; J. Lassen; L. A. Orozco; M. R. Pearson; S. Raeder; A. Teigelhöfer

2014-09-30T23:59:59.000Z

382

Analytical Solutions for the Nonlinear Longitudinal Drift Compression (Expansion) of Intense Charged Particle Beams  

SciTech Connect (OSTI)

To achieve high focal spot intensities in heavy ion fusion, the ion beam must be compressed longitudinally by factors of ten to one hundred before it is focused onto the target. The longitudinal compression is achieved by imposing an initial velocity profile tilt on the drifting beam. In this paper, the problem of longitudinal drift compression of intense charged particle beams is solved analytically for the two important cases corresponding to a cold beam, and a pressure-dominated beam, using a one-dimensional warm-fluid model describing the longitudinal beam dynamics.

Edward A. Startsev; Ronald C. Davidson

2004-04-09T23:59:59.000Z

383

Effect of low energy oxygen ion beam irradiation on ionic conductivity of solid polymer electrolyte  

SciTech Connect (OSTI)

Over the past three decades, solid polymer electrolytes (SPEs) have drawn significant attention of researchers due to their prospective commercial applications in high energy-density batteries, electrochemical sensors and super-capacitors. The optimum conductivity required for such applications is about 10{sup ?2} – 10{sup ?4} S/cm, which is hard to achieve in these systems. It is known that the increase in the concentration of salt in the host polymer results in a continuous increase in the ionic conductivity. However, there is a critical concentration of the salt beyond which the conductivity decreases due to formation of ion pairs with no net charge. In the present study, an attempt is made to identify the concentration at which ion pair formation occurs in PEO: RbBr. We have attempted to modify microstructure of the host polymer matrix by low energy ion (Oxygen ion, O{sup +1} with energy 100 keV) irradiation. Ionic conductivity measurements in these systems were carried out using Impedance Spectroscopy before and after irradiation to different fluencies of the oxygen ion. It is observed that the conductivity increases by one order in magnitude. The increase in ionic conductivity may be attributed to the enhanced segmental motion of the polymer chains. The study reveals the importance of ion irradiation as an effective tool to enhance conductivity in SPEs.

Manjunatha, H., E-mail: gnk-swamy@blr.amrita.edu; Kumaraswamy, G. N., E-mail: gnk-swamy@blr.amrita.edu [Department of Physics, Amrita Vishwa Vidyapeetham, Bengaluru-560035 (India); Damle, R. [Department of Physics, Bangalore University, Bengaluru-560056 (India)

2014-04-24T23:59:59.000Z

384

E-Print Network 3.0 - argon ion beam Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

a conceptual layout of a neutralization system. For NTX... ( 10-3 Torr). Final focus magnet Target Volumetric plasma ... Source: Gilson, Erik - Princeton Plasma Physics...

385

A study of tungsten spectra using large helical device and compact electron beam ion trap in NIFS  

SciTech Connect (OSTI)

Tungsten spectra have been observed from Large Helical Device (LHD) and Compact electron Beam Ion Trap (CoBIT) in wavelength ranges of visible to EUV. The EUV spectra with unresolved transition array (UTA), e.g., 6g-4f, 5g-4f, 5f-4d and 5p-4d transitions for W{sup +24-+33}, measured from LHD plasmas are compared with those measured from CoBIT with monoenergetic electron beam ({<=}2keV). The tungsten spectra from LHD are well analyzed based on the knowledge from CoBIT tungsten spectra. The C-R model code has been developed to explain the UTA spectra in details. Radial profiles of EUV spectra from highly ionized tungsten ions have been measured and analyzed by impurity transport simulation code with ADPAK atomic database code to examine the ionization balance determined by ionization and recombination rate coefficients. As the first trial, analysis of the tungsten density in LHD plasmas is attempted from radial profile of Zn-like WXLV (W{sup 44+}) 4p-4s transition at 60.9A based on the emission rate coefficient calculated with HULLAC code. As a result, a total tungsten ion density of 3.5 Multiplication-Sign 10{sup 10}cm{sup -3} at the plasma center is reasonably obtained. In order to observe the spectra from tungsten ions in lower-ionized charge stages, which can give useful information on the tungsten influx in fusion plasmas, the ablation cloud of the impurity pellet is directly measured with visible spectroscopy. A lot of spectra from neutral and singly ionized tungsten are observed and some of them are identified. A magnetic forbidden line from highly ionized tungsten ions has been examined and Cd-like WXXVII (W{sup 26+}) at 3893.7A is identified as the ground-term fine-structure transition of 4f{sup 23}H{sub 5}-{sup 3}H{sub 4}. The possibility of {alpha} particle diagnostic in D-T burning plasmas using the magnetic forbidden line is discussed.

Morita, S.; Goto, M.; Murakami, I. [National Institute for Fusion Science, Toki 509-5292, Gifu (Japan); Department of Fusion Science, Graduate University for Advanced Studies, Toki 509-5292, Gifu (Japan); Dong, C. F.; Kato, D.; Sakaue, H. A.; Oishi, T. [National Institute for Fusion Science, Toki 509-5292, Gifu (Japan); Hasuo, M. [Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto 606-8501 (Japan); Koike, F. [Physics Laboratory, School of Medicine, Kitasato University, Sagamihara 252-0374 (Japan); Nakamura, N. [Institute of Laser Science, University of Electro-Communications, Tokyo 182-8585 (Japan); Sasaki, A. [Quantum Beam Science Directorate, Japan Atomic Energy Research Agency, Kizugawa 619-0215, Kyoto (Japan); Wang, E. H. [Department of Fusion Science, Graduate University for Advanced Studies, Toki 509-5292, Gifu (Japan)

2013-07-11T23:59:59.000Z

386

Recent Performance of the SNS H- ion source and low-energy beam transport system  

SciTech Connect (OSTI)

Recent measurements of the H beam current show that SNS is injecting about 55 mA into the RFQ compared to 45 mA in 2010. Since 2010, the H beam exiting the RFQ dropped from 40 mA to 34 mA, which is sufficient for 1 MW of beam power. To minimize the impact of the RFQ degradation, the service cycle of the best performing source was extended to 6 weeks. The only degradation is fluctuations in the electron dump voltage towards the end of some service cycles, a problem that is being investigated. Very recently, the RFQ was retuned, which partly restored its transmission. In addition, the electrostatic low-energy beam transport system was reengineered to double its heat sinking and equipped with a thermocouple that monitors the temperature of the ground electrode between the two Einzel lenses. The recorded data show that emissions from the source at high voltage dominate the heat load. Emissions from the partly Cs-covered first lens cause the temperature to peak several hours after starting up. On rare occasions, the temperature can also peak due to corona discharges between the center ground electrode and one of the lenses.

Stockli, Martin P [ORNL] [ORNL; Ewald, Kerry D [ORNL] [ORNL; Han, Baoxi [ORNL] [ORNL; Murray Jr, S N [ORNL] [ORNL; Pennisi, Terry R [ORNL] [ORNL; Piller, Chip [ORNL] [ORNL; Santana, Manuel [ORNL] [ORNL; Tang, Johnny Y [ORNL] [ORNL; Welton, Robert F [ORNL] [ORNL

2014-01-01T23:59:59.000Z

387

SIMULATION OF CLUSTER IMPACT INDUCED DESORPTION AND COOLING Surrey Ion Beam Centre  

E-Print Network [OSTI]

caused by a high energy C60 impact can eject a large polystyrene molecule without fragmentation spectrometry (SIMS) as a probing beam is showing great promise for the analysis of large organic molecules on ejection. Unlike the sputtering process this desorption process does not require that the binding energy

Webb, Roger P.

388

SHyPIE A NEW SOURCE FOR ON LINE PRODUCTION OF MULTICHARGED RADIOACTIVE CONDENSABLE ION BEAMS  

E-Print Network [OSTI]

Chouaib Doukkali, Faculte des Sciences, 24000 El ladida Morocco In order to define the future intensity and reliability of the on line radioactive beams for the SPIRAL project, an intense activity of research, with energies up to 95.A MeV and intensities up to 6 1012 particles/s for the lightest elements. The primary

Paris-Sud XI, Université de

389

PERMANENT MAGNETS UNDER IRRADIATION AND RADIOACTIVE ALKALI ION BEAM DEVELOPMENT FOR SPIRAL 1  

E-Print Network [OSTI]

produced by nuclear reactions are released from the high temperature target (2000°C), effuse through a cold transfer tube up to a multi-charged ECR ion source. After extraction from the ECRIS at low energy ( 34 q of high-energy fragmentation as well as the ISOL methods for exploring the structure of nuclei far from

Boyer, Edmond

390

An innovative accelerator-driven inertial electrostatic confinement device using converging ion beams  

SciTech Connect (OSTI)

Fundamental physics issues facing development of fusion power on a small-scale are assessed with emphasis on the idea of Inertial Electrostatic Confinement (IEC). The authors propose a new concept of accelerator-driven IEC fusion, termed Converging Beam Inertial Electrostatic Confinement (CB-IEC). CB-IEC offers a number of innovative features that make it an attractive pathway toward resolving fundamental physics issues and assessing the ultimate viability of the IEC concept for power generation.

Bauer, T. H.; Wigeland, R. A.

1999-12-08T23:59:59.000Z

391

Synthesis of focusing-and-deflection columns  

SciTech Connect (OSTI)

Szilagyi and Szep have demonstrated that focusing lenses of high performances can be constructed from a column of circular plate electrodes. Later, Szilagyi modified that system to include dipole, quadrupole, and octupole components by partitioning each plate into eight equal sectors. It has already been shown that the additional quadrupole components can indeed bring about substantial improvements in the focusing of charged particle beams. In this article, that design procedure is expanded to construct columns capable of both focusing and deflecting particle beams by just introducing additional dipole components. In this new design, the geometry of the system remains unchanged. The only extra complication is the demand for more individual controls of the sector voltages. Two sample designs, one for negative ions and one for electrons, are presented showing that in both cases a {plus_minus}2.3 mrad diverging beam can be focused down to a spot of less than 50 nm in radius over a scanning circular area of radius 0.25 mm. The details of the two systems are given in Sec. IV along with the source conditions. The performance of the negative ion system is found to be comparable to the published data. For the relativistic electron system, the interaction of individual components to reduce various aberrations is investigated. {copyright} {ital 1995} {ital American} {ital Vacuum} {ital Society}

Szilagyi, M.; Mui, P.H. [Department of Electrical and Computer Engineering, University of Arizona, Tucson, Arizona 85721 (United States)] [Department of Electrical and Computer Engineering, University of Arizona, Tucson, Arizona 85721 (United States)

1995-03-01T23:59:59.000Z

392

Contribution of ion beam analysis methods to the development of 2nd generation high temperature superconducting (HTS) wires  

SciTech Connect (OSTI)

One of the crucial steps in the second generation high temperature superconducting wire program was development of the buffer layer architecture. The architecture designed at the Superconductivity Technology Center at Los Alamos National Laboratory consists of several oxide layers wherein each layer plays a specific role, namely: nucleation layer, diffusion barrier, biaxially textured template, and an intermediate layer with a good match to the lattice parameter of superconducting Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7} (YBCO) compound. This report demonstrates how a wide range of ion beam analysis techniques (SIMS, RBS, channeling, PIXE, PIGE, NRA, ERD) was employed for analysis of each buffer layer and the YBCO films. These results assisted in understanding of a variety of physical processes occurring during the buffet layer fabrication and helped to optimize the buffer layer architecture as a whole.

Usov, Igor O [Los Alamos National Laboratory; Arendt, Paul N [Los Alamos National Laboratory; Stan, Liliana [Los Alamos National Laboratory; Holesinger, Terry G [Los Alamos National Laboratory; Foltyn, Steven R [Los Alamos National Laboratory; Depaula, Raymond F [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

393

Tunneling conductance studies in the ion-beam sputtered CoFe/Mg/MgO/NiFe magnetic tunnel junctions  

SciTech Connect (OSTI)

Magnetic tunnel junctions consisting of CoFe(10 nm)/Mg(1 nm)/MgO(3.5 nm)/NiFe(10 nm) are grown at room temperature using dual ion beam sputtering via in-situ shadow masking. The effective barrier thickness and average barrier height are estimated to be 3.5 nm (2.9 nm) and 0.69 eV (1.09 eV) at 290 K (70 K), respectively. The tunnel magnetoresistance value of 0.2 % and 2.3 % was observed at 290 K and 60 K, respectively. The temperature dependence of tunneling conductance revealed the presence of localized states present within the forbidden gap of the MgO barrier leading to finite inelastic spin independent tunneling contributions, which degrade the TMR value.

Singh, Braj Bhusan; Chaudhary, Sujeet [Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016 (India)

2013-06-03T23:59:59.000Z

394

TEM and x-ray investigation of single crystal-like zirconia films fabricated by dual ion beam deposition  

SciTech Connect (OSTI)

Single crystal-like yttria-stabilized zirconia (YSZ) thin films have been deposited on amorphous quartz, polycrystalline zirconia, single crystal Si, and Hastelloy substrates using dual ion beam deposition (IBAD). These films are highly crystallographically aligned both normal to and within the film plane. The films are deposited at low substrate temperatures (< 200 C), and the film orientation is substrate independent. 0--20 X-ray diffraction, X-ray rocking curves, X-ray pole figures and X-ray phi scans are used to evaluate the film structure. High resolution cross-sectional TEM is used to examine the evolution of crystallographic film alignment on an amorphous quartz substrate. The data suggest that the evolution of biaxial alignment is nucleation controlled under these conditions.

Ressler, K.G.; Sonnenberg, N.; Cima, M.J. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Ceramics Processing Research Lab.

1996-12-31T23:59:59.000Z

395

Current-driven ion-acoustic and potential-relaxation instabilities excited in plasma plume during electron beam welding  

SciTech Connect (OSTI)

Many papers have sought correlations between the parameters of secondary particles generated above the beam/work piece interaction zone, dynamics of processes in the keyhole, and technological processes. Low- and high-frequency oscillations of the current, collected by plasma have been observed above the welding zone during electron beam welding. Low-frequency oscillations of secondary signals are related to capillary instabilities of the keyhole, however; the physical mechanisms responsible for the high-frequency oscillations (>10 kHz) of the collected current are not fully understood. This paper shows that peak frequencies in the spectra of the collected high-frequency signal are dependent on the reciprocal distance between the welding zone and collector electrode. From the relationship between current harmonics frequency and distance of the collector/welding zone, it can be estimated that the draft velocity of electrons or phase velocity of excited waves is about 1600 m/s. The dispersion relation with the properties of ion-acoustic waves is related to electron temperature 10 000 K, ion temperature 2 400 K and plasma density 10{sup 16} m{sup ?3}, which is analogues to the parameters of potential-relaxation instabilities, observed in similar conditions. The estimated critical density of the transported current for creating the anomalous resistance state of plasma is of the order of 3 A·m{sup ?2}, i.e. 8 mA for a 3–10 cm{sup 2} collector electrode. Thus, it is assumed that the observed high-frequency oscillations of the current collected by the positive collector electrode are caused by relaxation processes in the plasma plume above the welding zone, and not a direct demonstration of oscillations in the keyhole.

Trushnikov, D. N., E-mail: trdimitr@yandex.ru [The department for Applied Physics, Perm National Research Polytechnic University, Perm, 614990 (Russian Federation); Mladenov, G. M., E-mail: gmmladenov@abv.bg; Koleva, E. G., E-mail: eligeorg@abv.bg [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradsko Shose, 1784, Sofia (Bulgaria); Technology Centre of Electron Beam and Plasma Technologies and Techniques, 68-70 Vrania, ap.10, Banishora,1309, Sofia (Bulgaria); Belenkiy, V. Ya., E-mail: mtf@pstu.ru; Varushkin, S. V., E-mail: stepan.varushkin@mail.ru [The department for Welding Production and Technology of Constructional Materials, Perm National Research Polytechnic University, Perm, 614990 (Russian Federation)

2014-04-15T23:59:59.000Z

396

Smoothing metallic glasses without introducing crystallization by gas cluster ion beam  

SciTech Connect (OSTI)

We show that 30 keV Ar cluster ion bombardment of Ni{sub 52.5}Nb{sub 10}Zr{sub 15}Ti{sub 15}Pt{sub 7.5} metallic glass (MG) can remove surface mountain-like features and reduce the root mean square surface roughness from 12 nm to 0.7 nm. X-ray diffraction analysis reveals no crystallization after cluster ion irradiation. Molecular dynamics simulations show that, although damage cascades lead to local melting, the subsequent quenching rate is a few orders of magnitude higher than the critical cooling rate for MG formation, thus the melted zone retains its amorphous nature down to room temperature. These findings can be applied to obtain ultra-smooth MGs without introducing crystallization.

Shao, Lin; Chen, Di; Myers, Michael; Wang, Jing [Department of Nuclear Engineering and Materials Science and Engineering Program, Texas A and M University, College Station, Texas 77843 (United States)] [Department of Nuclear Engineering and Materials Science and Engineering Program, Texas A and M University, College Station, Texas 77843 (United States); Tilakaratne, Buddhi; Wijesundera, Dharshana; Chu, Wei-Kan [Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, Texas 77004 (United States)] [Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, Texas 77004 (United States); Xie, Guoqiang [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)] [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Zare, Arezoo; Lucca, Don A. [School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, Oklahoma 74078 (United States)] [School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, Oklahoma 74078 (United States)

2013-03-11T23:59:59.000Z

397

Production of Liquid Cluster Ions by Nozzle Beam Source with and without He Gas  

SciTech Connect (OSTI)

We developed a new type of cluster ion source which could produce various kinds of liquid clusters such as water, methanol, ethanol and octane clusters. When the vapor pressure was larger than one atm, the water and ethanol clusters could be produced by an adiabatic expansion phenomenon without adding He gas. The peak size of the cluster ions increased with the increase of the vapor pressures. When the source temperature was at room temperature, the water and ethanol clusters were also produced by adding He gas. In another case of producing liquid clusters such as methanol and octane clusters, He gas was added to mix up with vapors of liquid materials. When the He gas pressure was larger than a few atms, the methanol and octane clusters were produced at a vapor pressure of two atm. The peak size increased with increase of the vapor pressure as well as the He gas pressure.

Takaoka, G. H.; Ryuto, H.; Okada, T.; Sugiyama, K. [Photonics and Electronics Science and Engineering Center, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan)

2008-11-03T23:59:59.000Z

398

Polarity-inverted ScAlN film growth by ion beam irradiation and application to overtone acoustic wave (000-1)/(0001) film resonators  

SciTech Connect (OSTI)

Polarity inversion in wurtzite film is generally achieved by the epitaxial growth on a specific under-layer. We demonstrate polarity inversion of c-axis oriented ScAlN films by substrate ion beam irradiation without using buffer layer. Substrate ion beam irradiation was induced by either sputtering a small amount of oxide (as a negative ion source) onto the cathode or by applying a RF bias to the substrate. Polarity of the films was determined by a press test and nonlinear dielectric measurement. Second overtone thickness extensional mode acoustic resonance and suppression of fundamental mode resonance, indicating complete polarity inversion, were clearly observed in bilayer highly oriented (000-1)/(0001) ScAlN film.

Suzuki, Masashi; Yanagitani, Takahiko, E-mail: yana@nitech.ac.jp [Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Odagawa, Hiroyuki [Kumamoto National College of Technology, Kumamoto 861-1102 (Japan)

2014-04-28T23:59:59.000Z

399

Experiments with planar inductive ion source meant for creation ofH+ Beams  

SciTech Connect (OSTI)

In this article the effect of different engineering parameters of an rf-driven ion sources with external spiral antenna and quartz disk rf-window are studied. Paper consists of three main topics: The effect of source geometry on the operation gas pressure, the effect of source materials and magnetic confinement on extracted current density and ion species and the effect of different antenna geometries on the extracted current density. The operation gas pressure as a function of the plasma chamber diameter, was studied. This was done with three cylindrical plasma chambers with different inner diameters. The chamber materials were studied using two materials, aluminum and alumina (AlO{sub 2}). The removable 14 magnet multicusp confinement arrangement enabled us to compare the effects of the two wall materials with and without the magnetic confinement. Highest proton fraction of {approx} 8% at 2000 W of rf-power and at pressure of 1.3 Pa was measured using AlO{sub 2} plasma chamber and no multicusp confinement. For all the compared ion sources at 1000W of rf-power, source with multicusp confinement and AlO2 plasma chamber yields highest current density of 82.7 mA/cm{sup 2} at operation pressure of 4 Pa. From the same source highest measured current density of 143 mA/cm{sup 2} at 1.3 Pa and 2200W of rf-power was achieved. Multicusp confinement increased the maximum extracted current up to factor of two. Plasma production with different antenna geometries was also studied. Antenna tests were performed using same source geometry as in source material study with AlO{sub 2} plasma chamber and multicusp confinement. The highest current density was achieved with 4.5 loop solenoid antenna with 6 cm diameter. Slightly lower current density with lower pressure was achieved using tightly wound 3 loop spiral antenna with 3.3 cm ID and 6 cm OD.

Vainionpaa, J.H.; Kalvas, T.; Hahto, S.K.; Reijonen, J.

2007-02-07T23:59:59.000Z

400

Anomalous Electron Transport Due to Multiple High Frequency Beam Ion Driven Alfven Eigenmode  

SciTech Connect (OSTI)

We report on the simulations of recently observed correlations of the core electron transport with the sub-thermal ion cyclotron frequency instabilities in low aspect ratio plasmas of the National Spherical Torus Experiment (NSTX). In order to model the electron transport of the guiding center code ORBIT is employed. A spectrum of test functions of multiple core localized Global shear Alfven Eigenmode (GAE) instabilities based on a previously developed theory and experimental observations is used to examine the electron transport properties. The simulations exhibit thermal electron transport induced by electron drift orbit stochasticity in the presence of multiple core localized GAE.

N.N. Gorelenkov, D. Stutman, K. Tritz, A. Boozer, L. Delgardo-Aparicio, E. Fredrickson, S. Kaye, and R. White

2010-07-13T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

FOCUSING AND NEUTRALIZATION OF INTENSE BEAMS Simon S. Yu, Andre Anders, F.M. Bieniosek, Shmuel Eylon, Enrique Henestroza, Prabir Roy,  

E-Print Network [OSTI]

is essential for the viability of an economically competitive heavy ion fusion power plant. The physics of theoretical predictions with experiment, the Heavy Ion Fusion Virtual National Laboratory has completed

Gilson, Erik

402

The Research Program at RIBRAS (Radioactive Ion Beams in Brasil)-III  

SciTech Connect (OSTI)

A part of the research program developed in the RIBRAS facility over the last four years is presented. Experiments using radioactive secondary beams of light exotic nuclei such as {sup 6}He, {sup 7}Be, {sup 8}Li on several targets have been performed. Elastic angular distributions have been analysed by the Optical Model and four body Continuous Discretized Coupled Channels Calculations (4b-CDCC) and the total reaction cross sections have been obtained. A comparison between the reaction cross sections of {sup 6}He and other stable projectiles with medium-heavy targets was performed. Measurements of the proton transfer reaction {sup 12}C({sup 8}Li,{sup 9}Be){sup 11}B are also presented.

Lichtenthaeler, R.; Lepine-Szily, A.; Guimaraes, V.; Faria, P. N. de; Mendes, D. R. Jr; Pires, K. C. C.; Morcelle, V.; Barioni, A.; Morais, M. C.; Pampa Condori, R. [Instituto de Fisica da USP, Sao Paulo, Brazil, C.P. 66318, 05314-970 (Brazil); Assuncao, M. [Departamento de Ciencias Exatas e da Terra, Unifesp, Campus de Diadema, Sao Paulo (Brazil); Moro, A. M. [Departamento de FAMN, Universidad de Sevilla, Apdo. 1065, E-41080, Sevilla (Spain); Rodriguez-Gallardo, M. [Departamento de FAMN, Universidad de Sevilla, Apdo. 1065, E-41080, Sevilla (Spain); Instituto de Estructura de la Materia, CSIC, Serrano 123, E-28006 Madrid (Spain); Arazi, A. [Laboratorio TANDAR, Comision Nacional de Energia Atomica (Argentina)

2010-04-30T23:59:59.000Z

403

Compact microwave ion source for industrial applications  

SciTech Connect (OSTI)

A 2.45 GHz microwave ion source for ion implanters has many good properties for industrial application, such as easy maintenance and long lifetime, and it should be compact for budget and space. But, it has a dc current supply for the solenoid and a rf generator for plasma generation. Usually, they are located on high voltage platform because they are electrically connected with beam extraction power supply. Using permanent magnet solenoid and multi-layer dc break, high voltage deck and high voltage isolation transformer can be eliminated, and the dose rate on targets can be controlled by pulse duty control with semiconductor high voltage switch. Because the beam optics does not change, beam transfer components, such as focusing elements and beam shutter, can be eliminated. It has shown the good performances in budget and space for industrial applications of ion beams.

Cho, Yong-Sub; Kim, Dae-Il; Kim, Han-Sung; Seol, Kyung-Tae; Kwon, Hyeok-Jung; Hong, In-Seok [Proton Engineering Frontier Project, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of)

2012-02-15T23:59:59.000Z

404

Efficient low-beta H-mode accelerating structures with PMQ focusing  

SciTech Connect (OSTI)

We are developing high-efficiency room-temperature RF accelerating structures for beam velocities in the range of a few percent of the speed of light by merging two well-known ideas: H-mode cavities and the transverse beam focusing with permanent-magnet quadrupoles (PMQ). Combining electromagnetic 3-D modeling with beam dynamics simulations and thermal-stress analysis, we have found that the H-mode structures with PMQ focusing provide a very efficient and practical accelerator for light-ion beams of considerable currents. Such accelerating structures following a short RFQ can be used in the front end of ion linacs or in stand-alone applications such as a compact deuteron-beam accelerator up to the energy of a few MeV.

Kurennoy, Sergey S [Los Alamos National Laboratory; O' Hara, James F [Los Alamos National Laboratory; Olivas, Eric R [Los Alamos National Laboratory; Rybarcyk, Lawrence J [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

405

Small beam nonparaxiality arrests selffocusing of optical beams Gadi Fibich  

E-Print Network [OSTI]

Small beam nonparaxiality arrests self­focusing of optical beams Gadi Fibich Department­focusing in the presence of small beam nonparaxiality is derived. Analysis of this equation shows that nonparaxiality remains small as the beam propa­ gates. Nevertheless, nonparaxiality arrests self­focusing when the beam

Soatto, Stefano

406

Design of a compact, permanent magnet electron cyclotron resonance ion source for proton and H{sub 2}{sup +} beam production  

SciTech Connect (OSTI)

A 2.45 GHz microwave ion source was developed at China Institute of Atomic Energy (CIAE) for proton beam production of over 60 mA [B.-Q. Cui, Y.-W. Bao, L.-Q. Li, W.-S. Jiang, and R.-W. Wang, Proceedings of the High Current Electron Cyclotron Resonance (ECR) Ion Source for Proton Accelerator, APAC-2001, 2001 (unpublished)]. For various proton beam applications, another 2.45 GHz microwave ion source with a compact structure is designed and will be built at CIAE as well for high current proton beam production. It is also considered to be used for the test of H{sub 2}{sup +} beam, which could be injected into the central region model cyclotron at CIAE, and accelerated to 5 MeV before extraction by stripping. The required ECR magnetic field is supplied by all the permanent magnets rather than electrical solenoids and six poles. The magnetic field distribution provided by this permanent magnets configuration is a large and uniformly volume of ECR zone, with central magnetic field of a magnitude of {approx}875 Gs[T. Taylor and J. S. C. Wills, Nucl. Instrum. Methods Phys. Res. A 309, 37 (1991)]. The field adjustment at the extraction end can be implemented by moving the position of the magnet blocks. The results of plasma, coupling with 2.45 GHz microwave in the ECR zone inside the ion source are simulated by particle-in-cell code to optimize the density by adjusting the magnetic field distribution. The design configuration of the ion source will be summarized in the paper.

Jia Xianlu; Zhang Tianjue; Wang Chuan; Zheng Xia; Yin Zhiguo; Zhong Junqing; Wu Longcheng; Qin Jiuchang [China Institute of Atomic Energy, P.O. Box 275(3), Beijing 102413 (China); Luo Shan [The 6th Department, Communication Command Academy, Wuhan 430010 (China)

2010-02-15T23:59:59.000Z

407

Axial magnetic field and toroidally streaming fast ions in the dense plasma focus are natural consequences of conservation laws in the curved axisymmetric geometry of the current sheath  

E-Print Network [OSTI]

Direct measurement of axial magnetic field in the PF-1000 dense plasma focus (DPF), and its reported correlation with neutron emission, call for a fresh look at previous reports of existence of axial magnetic field component in the DPF from other laboratories, and associated data suggesting toroidal directionality of fast ions participating in fusion reactions, with a view to understand the underlying physics. In this context, recent work dealing with application of the hyperbolic conservation law formalism to the DPF is extended in this paper to a curvilinear coordinate system, which reflects the shape of the DPF current sheath. Locally-unidirectional shock propagation in this coordinate system enables construction of a system of 7 one-dimensional hyperbolic conservation law equations with geometric source terms, taking into account all the components of magnetic field and flow velocity. Rankine-Hugoniot jump conditions for this system lead to expressions for the axial magnetic field and three components of ...

Auluck, S K H

2014-01-01T23:59:59.000Z

408

Spectroscopy at the high-energy electron beam ion trap (Super EBIT)  

SciTech Connect (OSTI)

The following progress report presents some of the x-ray measurements performed during the last year on the Livermore SuperEBIT facility. The measurements include: direct observation of the spontaneous emission of the hyperfine transition in ground state hydrogenlike holmium, {sup 165}Ho{sup 66{plus}}; measurements of the n {equals} 2 {r_arrow} 2 transition energies in neonlike thorium, Th{sup 80{plus}}, through lithiumlike thorium, Th{sup 87{plus}}, testing the predictions of quantum electrodynamical contributions in high-Z ions up to the 0.4{percent} level; measurements of the isotope shift of the n= 2 {r_arrow} 2 transition energies between lithiumlike through carbonize uranium, {sup 233}U{sup 89{plus}...86{plus}} and {sup 238}U{sup 89{plus}...86{plus}}, inferring the variation of the mean- square nuclear charge radius; and high-resolution measurements of the K{alpha} radiation of heliumlike xenon, Xe{sup 52 {plus}}, using a transmission-type crystal spectrometer, resolving for the first time the ls2p{sup 3}P{sub 1} {r_arrow} 1S{sup 2} {sup 1}S{sub 0} and ls2s{sup 3}S{sub 1} {r_arrow} 1S{sup 2} {sup 1}S{sub 0} transitions individually. 41 refs., 9 figs., 1 tab.

Widmann, K.; Beiersdorfer, P.; Crespo Lopez-Urrutia, J.R.

1996-07-10T23:59:59.000Z

409

Simulation of neutron displacement damage in bipolar junction transistors using high-energy heavy ion beams.  

SciTech Connect (OSTI)

Electronic components such as bipolar junction transistors (BJTs) are damaged when they are exposed to radiation and, as a result, their performance can significantly degrade. In certain environments the radiation consists of short, high flux pulses of neutrons. Electronics components have traditionally been tested against short neutron pulses in pulsed nuclear reactors. These reactors are becoming less and less available; many of them were shut down permanently in the past few years. Therefore, new methods using radiation sources other than pulsed nuclear reactors needed to be developed. Neutrons affect semiconductors such as Si by causing atomic displacements of Si atoms. The recoiled Si atom creates a collision cascade which leads to displacements in Si. Since heavy ions create similar cascades in Si we can use them to create similar damage to what neutrons create. This LDRD successfully developed a new technique using easily available particle accelerators to provide an alternative to pulsed nuclear reactors to study the displacement damage and subsequent transient annealing that occurs in various transistor devices and potentially qualify them against radiation effects caused by pulsed neutrons.

Doyle, Barney Lee; Buller, Daniel L.; Hjalmarson, Harold Paul; Fleming, Robert M; Bielejec, Edward Salvador; Vizkelethy, Gyorgy

2006-12-01T23:59:59.000Z

410

Study on space charge effect in an electrostatic ion analyzer applied to measure laser produced ions  

SciTech Connect (OSTI)

The abundance of different ions produced by laser ion sources is usually analyzed by an electrostatic ion analyzer (EIA). Ion current intensities in the range of several mA/cm{sup 2} at the position of the EIA have been achieved from the laser ion source developed by the Institute of Modern Physics; this indicates that a noticeable influence of space charge effect during the ion transmission will occur. Hence, while the parameters of the EIA or the beams are changed, such as ion species, current intensity, the ions’ transmission efficiency through the EIA is different, which will result in an uncertainty in the estimation of the ions’ yields. Special attention is focused on this issue in this paper. Ion's transmissions through the EIA under different circumstances are studied with simulations and experiments, the results of which are consistent with each other.

Jin, Q. Y.; Li, Zh. M.; Liu, W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China) [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhao, H. Y., E-mail: zhaohy@impcas.ac.cn; Sha, S.; Zhang, J. J.; Zhang, X. Zh.; Sun, L. T.; Zhao, H. W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)] [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2014-03-15T23:59:59.000Z

411

Patient-specific QA and delivery verification of scanned ion beam at NIRS-HIMAC  

SciTech Connect (OSTI)

Purpose: To evaluate a patient-specific QA program and system for constancy checking of a scanning delivery system developed at the National Institute of Radiological Sciences.Methods: For the patient-specific QA, all the planned beams are recalculated on a water phantom with treatment planning software (TPS). The recalculated dose distributions are compared with the measured distributions using a 2D ionization chamber array at several depths, and evaluated using gamma index analysis with criteria of 3% and 3 mm and a pass rate of 90%. For the constancy check, the authors developed the multiwire proportional chamber (MWPC), which can record the delivered 2D fluence images in a slice-by-slice manner. During irradiation for dosimetric QA with the 2D ionization chamber array and an accordion-type water phantom, the 2D fluence images are recorded using the MWPC in the delivery system. These recorded images are then compared to those taken in the treatment session to check the constancy check. This analysis also employs gamma index analysis using the same criteria as in the patient-specific QA. These patient-specific QA and constancy check evaluations were performed using the data of 122 patients.Results: In the patient-specific QA, the measured dose distributions agreed well with those calculated by the TPS, and the QA criteria were satisfied in all measurements. The additional check of the fluence comparison ensured the constancy of the delivered field during each treatment irradiation.Conclusions: The authors established a patient-specific QA program and additional check of delivery constancy in every treatment session. Fluence comparison is a strong tool for constancy checking of the delivery system.

Furukawa, Takuji; Inaniwa, Taku; Hara, Yousuke; Mizushima, Kota; Shirai, Toshiyuki; Noda, Koji [Medical Physics Research Group, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)] [Medical Physics Research Group, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

2013-12-15T23:59:59.000Z

412

Axial magnetic field and toroidally streaming fast ions in the dense plasma focus are natural consequences of conservation laws in the curved axisymmetric geometry of the current sheath  

SciTech Connect (OSTI)

Direct measurement of axial magnetic field in the PF-1000 dense plasma focus (DPF), and its reported correlation with neutron emission, call for a fresh look at previous reports of existence of axial magnetic field component in the DPF from other laboratories, and associated data suggesting toroidal directionality of fast ions participating in fusion reactions, with a view to understand the underlying physics. In this context, recent work dealing with application of the hyperbolic conservation law formalism to the DPF is extended in this paper to a curvilinear coordinate system, which reflects the shape of the DPF current sheath. Locally unidirectional shock propagation in this coordinate system enables construction of a system of 7 one-dimensional hyperbolic conservation law equations with geometric source terms, taking into account all the components of magnetic field and flow velocity. Rankine-Hugoniot jump conditions for this system lead to expressions for the axial magnetic field and three components of fluid velocity having high ion kinetic energy.

Auluck, S. K. H. [Physics Group, Bhabha Atomic Research Center, Mumbai 400085 (India)

2014-10-15T23:59:59.000Z

413

A 915 MHz/2. 45 GHz ECR plasma source for large area ion beam and plasma processing  

SciTech Connect (OSTI)

The technology for producing uniform, high density (10{sup 11}--10{sup 12}/cm{sup 3}) microwave discharges over cross sections of 50 cm{sup 2} is well established. The present challenge is to extend the high density, and electrodeless benefits of microwave discharges to produce uniform densities over an area of 300--700 cm{sup 2}. Such discharges have important applications for 6 to 8-in. single wafer processing and as large surface, broad beam, high current density ion sources. The design principles for scaling the 18 cm diam MPDR ECR cavity applicator technology to 38--47 cm diam are reviewed. Microwave discharges with diameters of 20--30 cm can be created when these applicators are excited with either 2.45 GHz or 915 MHz. The design and construction of a prototype cavity applicator with a 20 cm diam discharge is described. The discharge is enclosed with a 12-pole multicusp static magnetic field produced by 2-in. by 2-in. by 1-in. rare-earth magnets. Each magnet has a pole face field strength of 3 kG. The experimental test of this plasma source in argon gas excited with 2.45 GHz energy is reviewed.

Asmussen, J.; Hopwood, J.; Sze, F.C. (Department of Electrical Engineering, Michigan State University, East Lansing, Michigan 48824-1226 (US))

1990-01-01T23:59:59.000Z

414

Much simplified ion-beam assisted deposition-TiN template for high-performance coated conductors  

SciTech Connect (OSTI)

A much simplified template, i.e., two nonsuperconducting layers between the superconducting YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) and the polycrystalline metal substrate, has been developed for high-performance coated conductors by using biaxially aligned TiN as a seed layer. A combination of a thin TiN ({approx}10 nm by ion-beam assisted deposition) layer and an epitaxial buffer LaMnO{sub 3} layer ({approx}120 nm) allows us to grow epitaxial YBCO films with values of full width at half-maximum around 3.5 deg. and 1.7 deg. for the {phi}-scan of (103) and rocking curve of (005) YBCO, respectively. The YBCO films grown on electropolished polycrystalline Hastelloy using this two-layer template exhibited a superconducting transition temperature of 89.5 K, a critical current density of 1.2 MA/cm{sup 2} at 75.5 K, and an {alpha} value (proportional factor of critical current density J{sub c}{approx}H{sup -}{alpha}) of around 0.33, indicating a high density of pinning centers and an absence of weak links.

Xiong, J. [Division of Materials Physics and Applications, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); State Key Lab of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Matias, V.; Zhai, J. Y.; Maiorov, B.; Trugman, D.; Jia, Q. X. [Division of Materials Physics and Applications, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Wang, H. [Department of Electrical and Computer Engineering, Texas A and M University, College Station, Texas 77843-3128 (United States); Tao, B. W.; Li, Y. R. [State Key Lab of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

2010-10-15T23:59:59.000Z

415

A new method of measuring the poloidal magnetic and radial electric fields in a tokamak using a laser-accelerated ion-beam trace probe  

SciTech Connect (OSTI)

Both the poloidal magnetic field (B{sub p}) and radial electric field (E{sub r}) are significant in magnetic confinement devices. In this paper, a new method was proposed to diagnose both B{sub p} and E{sub r} at the same time, which was named Laser-accelerated Ion-beam Trace Probe (LITP). This method based on the laser-accelerated ion beam, which has three properties: large energy spread, short pulse lengths, and multiple charge states. LITP can provide the 1D profiles, or 2D images of both B{sub p} and E{sub r}. In this paper, we present the basic principle and some preliminary theoretical results.

Yang, X. Y.; Chen, Y. H.; Lin, C.; Wang, X. G.; Xiao, C. J., E-mail: cjxiao@pku.edu.cn [State Key Labaratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Wang, L. [Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190 (China); Xu, M. [Center for Fusion Science of Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China)

2014-11-15T23:59:59.000Z

416

Ion-beam-induced magnetic and structural phase transformation of Ni-stabilized face-centered-cubic Fe films on Cu(100)  

SciTech Connect (OSTI)

Metastable face-centered cubic (fcc) Fe/Cu(100) thin films are good candidates for ion-beam magnetic patterning due to their magnetic transformation upon ion-beam irradiation. However, pure fcc Fe films undergo spontaneous transformation when their thickness exceeds 10 ML. This limit can be extended to approximately 22 ML by deposition of Fe at increased CO background pressures. We show that much thicker films can be grown by alloying with Ni for stabilizing the fcc ? phase. The amount of Ni necessary to stabilize nonmagnetic, transformable fcc Fe films in dependence on the residual background pressure during the deposition is determined and a phase diagram revealing the transformable region is presented.

Gloss, Jonas [Institute of Applied Physics, Vienna University of Technology, 1040 Vienna (Austria) [Institute of Applied Physics, Vienna University of Technology, 1040 Vienna (Austria); Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2, 616 69 Brno (Czech Republic); Shah Zaman, Sameena [Institute of Applied Physics, Vienna University of Technology, 1040 Vienna (Austria) [Institute of Applied Physics, Vienna University of Technology, 1040 Vienna (Austria); Comsats Institute of Information Technology, Park Road, 44000 Islamabad (Pakistan); Jonner, Jakub; Novotny, Zbynek; Schmid, Michael [Institute of Applied Physics, Vienna University of Technology, 1040 Vienna (Austria)] [Institute of Applied Physics, Vienna University of Technology, 1040 Vienna (Austria); Varga, Peter [Institute of Applied Physics, Vienna University of Technology, 1040 Vienna (Austria) [Institute of Applied Physics, Vienna University of Technology, 1040 Vienna (Austria); CEITEC BUT, Brno University of Technology, Technická 10, 616 00 Brno (Czech Republic); Urbánek, Michal [Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2, 616 69 Brno (Czech Republic) [Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2, 616 69 Brno (Czech Republic); CEITEC BUT, Brno University of Technology, Technická 10, 616 00 Brno (Czech Republic)

2013-12-23T23:59:59.000Z

417

A TALE OF TWO BEAMS: GAUSSIAN BEAMS AND BESSEL BEAMS ROBERT L. NOWACK  

E-Print Network [OSTI]

A TALE OF TWO BEAMS: GAUSSIAN BEAMS AND BESSEL BEAMS ROBERT L. NOWACK Abstract. An overview is given of two types of focused beams, Gaussian beams and Bessel beams. First I describe some of the basic properties of Gaussian beams in homogeneous media which stay collimated over a certain distance range after

Nowack, Robert L.

418

Self-pinched transport of a high ?/? electron beam  

SciTech Connect (OSTI)

The self-pinched transport of a 0.5 MeV, 18 kA cylindrical electron beam has been studied experimentally and computationally. The relatively low voltage and high current required for materials surface modification applications leads to complicated beam dynamics as the Alfven limit is approached. Transport and focusing of the high ?/? beam was done in a sub-Torr, neutral gas-filled, conducting tube in the ion-focused regime. In this regime, beam space charge forces are progressively neutralized to allow focusing of the beam by its self-magnetic field. The beam exhibits stable envelope oscillations as it is efficiently and reproducibly propagated for distances greater than a betatron wavelength. Experimental results follow the trends seen in 2-D particle-in-cell simulations. Results show that the input electron beam can be periodically focused to a peaked profile with the beam half-current radius decreased by a factor of 2.84. This results in an increase of a factor of 8 in beam current density. This focusing is sufficient to produce desired effects in the surface layers of metallic materials.

Myers, M. C.; Wolford, M. F.; Sethian, J. D. [U.S. Naval Research Laboratory, Plasma Physics Division, 4555 Overlook Ave., SW, Washington DC 20375 (United States)] [U.S. Naval Research Laboratory, Plasma Physics Division, 4555 Overlook Ave., SW, Washington DC 20375 (United States); Rose, D. V. [Voss Scientific, 418 Washington St. SE, Albuquerque, New Mexico 87108 (United States)] [Voss Scientific, 418 Washington St. SE, Albuquerque, New Mexico 87108 (United States); Hegeler, F. [Commonwealth Technology Inc., 5875 Barclay Drive, Alexandria, Virginia 22315 (United States)] [Commonwealth Technology Inc., 5875 Barclay Drive, Alexandria, Virginia 22315 (United States)

2013-10-15T23:59:59.000Z

419

Atom penetration from a thin film into the substrate during sputtering by polyenergetic Ar{sup +} ion beam with mean energy of 9.4 keV  

SciTech Connect (OSTI)

Penetration of alien atoms (Be, Ni) into Be, Al, Zr, Si and diamond was investigated under Ar{sup +} ion bombardment of samples having thermally evaporated films of 30--50 nm. Sputtering was carried out using a wide energy spectrum beam of Ar{sup +} ions of 9.4 keV to dose D = 1 {times} 10{sup 16}--10{sup 19} ion/cm{sup 2}. Implanted atom distribution in the targets was measured by Rutherford backscattering spectrometry (RBS) of H{sup +} and He{sup +} ions with energy of 1.6 MeV as well as secondary ion mass-spectrometry (SIMS). During the bombardment, the penetration depth of Ar atoms increases with dose linearly. This depth is more than 3--20 times deeper than the projected range of bombarding ions and recoil atoms. This is a deep action effect. The analysis shows that the experimental data for foreign atoms penetration depth are similar to the data calculated for atom migration through the interstitial site in a field of internal (lateral) compressive stresses created in the near-surface layer of the substrate as a result of implantation. Under these experimental conditions atom ratio r{sub i}/r{sub m} (r{sub i} -- radius of dopant, r{sub m} -- radius target of substrate) can play a principal determining role.

Kalin, B.A.; Gladkov, V.P.; Volkov, N.V.; Sabo, S.E. [Moscow Engineering Physics Inst. (Russian Federation)

1995-12-31T23:59:59.000Z

420

Neutrino Factories and Beta Beams  

E-Print Network [OSTI]

a Neutrino Factory Based on Muon Beams,” Proc. 2001 ParticleMD. [19] C. Rubbia et al. , “Beam Cooling with Ionisationthe required unstable ion beams has recently been suggested

Zisman, Michael S.

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "focused ion beam" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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421

Neutral beam monitoring  

DOE Patents [OSTI]

Method and apparatus for monitoring characteristics of a high energy neutral beam. A neutral beam is generated by passing accelerated ions through a walled cell containing a low energy neutral gas, such that charge exchange neutralizes the high energy ion beam. The neutral beam is monitored by detecting the current flowing through the cell wall produced by low energy ions which drift to the wall after the charge exchange. By segmenting the wall into radial and longitudinal segments various beam conditions are further identified.

Fink, Joel H. (Livermore, CA)

1981-08-18T23:59:59.000Z

422

Ion Beam Materials Lab  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region service area.PortaldefaultIntroducing AuroraInvestorPages

423

Physics with a very first low-energy beta-beam  

E-Print Network [OSTI]

We describe the importance of having low-energy (10-100 MeV) neutrino beams produced through the decay of boosted radioactive ions (``beta-beams''). We focus on the interest for neutrino-nucleus interaction studies and their impact for astrophysics, nuclear and particle physics. In particular, we discuss the relation to neutrinoless double-beta decay. Finally, we mention the status as far as the feasibility of low-energy beta-beams is concerned.

Cristina Volpe

2005-10-18T23:59:59.000Z

424

AN ADJUSTABLE THICKNESS Li/Be TARGET FOR FRAGMENTATION OF 3-kW HEAVY ION BEAMS  

E-Print Network [OSTI]

in the target and is carried away by the recirculating liquid lithium loop. It is designed for high power beams in the mass range from oxygen to calcium. Tapered beryllium windows combined with a uniform thickness lithium power of up to 3 kW is currently under construction for use with beams from oxygen to calcium

Harilal, S. S.

425

Holifield Radioactive Ion Beam Facility A leading international facility with unique capabilities for research in nuclear structure  

E-Print Network [OSTI]

questions that drive the field of low-energy nuclear physics: · How do protons and neutrons make stable Directions Nuclear structure and reaction research at HRIBF provides insight into the nature of the force species are available as low-energy (~50 keV) beams. More than 60 post-accelerated beams, including 132 Sn

426

High-pressure arcs as vacuum-atmosphere interface and plasma lens for nonvacuum electron beam welding machines, electron beam melting, and nonvacuum ion material modification  

SciTech Connect (OSTI)

Atmospheric pressure plasmas can be used to provide a vacuum-atmosphere interface as an alternative to differential pumping. Vacuum-atmosphere interface utilizing a cascade arc discharge was successfully demonstrated and a 175 keV electron beam was successfully propagated from vacuum through such a plasma interface and out into atmospheric pressure. Included in the article are a theoretical framework, experimental results, and possible applications for this novel interface. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Hershcovitch, A. [AGS Department, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)] [AGS Department, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)

1995-11-01T23:59:59.000Z

427

Transport properties of discontinuous Co{sub 80}Fe{sub 20}/Al{sub 2}O{sub 3} multilayers, prepared by ion beam sputtering  

SciTech Connect (OSTI)

Ion beam sputtered Co{sub 80}Fe{sub 20}(t)/Al{sub 2}O{sub 3}(30 {angstrom}) multilayers were obtained. The Co{sub 80}Fe{sub 20} layers become discontinuous for nominal thicknesses T {le} 18{angstrom}. Tunnel magnetoresistance was measured in CIP and CPP geometries, reaching up to 6.5% at room temperature and 11% at 15 K, for as-deposited films in CIP geometry. The temperature dependence of MR was found quite different for the two geometries: fairly strong in the CIP case and almost absent in the CPP geometry. A model is proposed to explain these large differences in behavior.

Kakazei, G.N.; Freitas, P.P.; Cardoso, S.; Lopes, A.M.L.; Pereira de Azevedo, M.M.; Pogorelov, Y.G.; Sousa, J.B.

1999-09-01T23:59:59.000Z

428

Heavy-ion broad-beam and microprobe studies of single-event upsets in 0.20 um SiGe heterojunction bipolar transistors and circuits.  

SciTech Connect (OSTI)

Combining broad-beam circuit level single-event upset (SEU) response with heavy ion microprobe charge collection measurements on single silicon-germanium heterojunction bipolar transistors improves understanding of the charge collection mechanisms responsible for SEU response of digital SiGe HBT technology. This new understanding of the SEU mechanisms shows that the right rectangular parallele-piped model for the sensitive volume is not applicable to this technology. A new first-order physical model is proposed and calibrated with moderate success.

Fritz, Karl (Mayo Foundation, Rochester, MN); Irwin, Timothy J. (Jackson & Tull Chartered Engineers, Washington, DC); Niu, Guofu (Auburn University, Auburn, AL); Fodness, Bryan (SGT, Inc., Greenbelt, MD); Carts, Martin A. (Raytheon ITSS, Greenbelt, MD); Marshall, Paul W. (Brookneal, VA); Reed, Robert A. (NASA/GSFC, Greenbelt, MD); Gilbert, Barry (Mayo Foundation, Rochester, MN); Randall, Barbara (Mayo Foundation, Rochester, MN); Prairie, Jason (Mayo Foundation, Rochester, MN); Riggs, Pam (Mayo Foundation, Rochester, MN); Pickel, James C. (PR& T, Inc., Fallbrook, CA); LaBel, Kenneth (NASA/GSFC, Greenbelt, MD); Cressler, John D. (Georgia Institute of Technology, Atlanta, GA); Krithivasan, Ramkumar (Georgia Institute of Technology, Atlanta, GA); Dodd, Paul Emerson; Vizkelethy, Gyorgy

2003-09-01T23:59:59.000Z