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1

The effect of cluster formation on mass separation in binary molecular beams  

E-Print Network [OSTI]

The effect of cluster formation on mass separation in binary molecular beams Wei Li,a) M. J composition of a skimmed supersonic binary molecular beam originally consisting of a 20% neon/80% xenon. © 2000 American Institute of Physics. S0021-9606 00 01806-7 I. INTRODUCTION Supersonic molecular beam

Sibener, Steven

2

A laser and molecular beam mass spectrometer study of low-pressure dimethyl ether flames  

SciTech Connect (OSTI)

The oxidation of dimethyl ether (DME) is studied in low-pressure flames using new molecular beam mass spectrometer and laser diagnostics. Two 30.0-Torr, premixed DME/oxygen/argon flames are investigated with stoichiometries of 0.98 and 1.20. The height above burner profiles of nine stable species and two radicals are measured. These results are compared to the detailed chemical reaction mechanism of Curran and coworkers. Generally good agreement is found between the model and data. The largest discrepancies are found for the methyl radical profiles where the model predicts qualitatively different trends in the methyl concentration with stoichiometry than observed in the experiment.

Andrew McIlroy; Toby D. Hain; Hope A. Michelsen; Terrill A. Cool

2000-12-15T23:59:59.000Z

3

Molecular beam mass spectrometric characterization of biomass pyrolysis products for fuels and chemicals  

SciTech Connect (OSTI)

Converting biomass feedstocks to fuels and chemicals requires rapid characterization of the wide variety of possible feedstocks. The combination of pyrolysis molecular beam mass spectrometry (Py-MBMS) and multivariate statistical analysis offers a unique capability for characterizing these feedstocks. Herbaceous and woody biomass feedstocks that were harvested at different periods were used in this study. The pyrolysis mass spectral data were acquired in real time on the MBMS, and multivariate statistical analysis (factor analysis) was used to analyze and classify Py-MBMS data into compound classes. The effect of harvest times on the thermal conversion of these feedstocks was assessed from these data. Apart from sericea lespedeza, the influence of harvest time on the pyrolysis products of the various feedstocks was insignificant. For sericea lespedeza, samples harvested before plant defoliation were significantly different from those harvested after defoliation. The defoliated plant samples had higher carbohydrate-derived pyrolysis products than the samples obtained from the foliated plant. Additionally, char yields from the defoliated plant samples were lower than those from the foliated plant samples.

Agblevor, F.A.; Davis, M.F.; Evans, R.J. [National Renewal Energy Lab., Golden, CO (United States)

1994-12-31T23:59:59.000Z

4

Rapid characterization of lignocellulosic feedstocks for fuels and chemicals: Molecular beam mass spectrometric approach  

SciTech Connect (OSTI)

Rapid characterization of biomass feedstocks has a pivotal role in the development of biomass energy because of the large number of samples that must be analyzed due to the diversity of biomass feedstocks and the significant differences in the chemical and physical properties of these feedstocks. Several biomass feedstocks (herbaceous, woody, and agricultural residues) were screened for the effects of storage, season of harvest, geographic location, clonal, and species variation on the pyrolysis products of the feed stocks. For herbaceous species such as sericea lespedeza, the season of harvest had a significant effect on the pyrolysis products. Effects of clonal variation on the composition of hybrid poplar feedstocks was easily discerned with the molecular beam mass spectrometric analysis. The effect of geographic location on the poplar clones pyrolysis products was minimal. However in the case of switchgrass, varietal influence on the pyrolysis products was minimal, but where the plant was grown had a strong influence on the pyrolysis products of the feedstock. Significant differences because of species variation could also be shown from the pyrolysis products of various biomass feedstocks. The influence of storage time on biomass samples stored outside in the open could also be discerned from the pyrolysis products of the feedstocks. The differences noted in the pyrolysis products of the feedstocks were noted for samples which were significantly degraded during storage either through the action of microflora or weathering.

Agblevor, F.A.; Davis, M.F. [National Renewable Energy Lab., Golden, CO (United States)

1996-12-31T23:59:59.000Z

5

REVIEW ARTICLE Taming molecular beams  

E-Print Network [OSTI]

REVIEW ARTICLE Taming molecular beams The motion of neutral molecules in a beam can be manipulated time-varying fields can be used to decelerate or accelerate beams of molecules to any desired velocity. We review the possibilities that this molecular-beam technology offers, ranging from ultrahigh

Loss, Daniel

6

Molecular beam mass spectrometry with tunable vacuum ultraviolet (VUV) synchrotron radiation  

E-Print Network [OSTI]

photoionization efficiency (PIE) curve can be plotted whicha photoionization efficiency curve (PIE) 3.1) Using the ALSto mass. 3.8) To plot a PIE curve, one easy way is to use a

Golan, Amir

2014-01-01T23:59:59.000Z

7

A compact molecular beam machine  

SciTech Connect (OSTI)

We have developed a compact, low cost, modular, crossed molecular beam machine. The new apparatus utilizes several technological advancements in molecular beams valves, ion detection, and vacuum pumping to reduce the size, cost, and complexity of a molecular beam apparatus. We apply these simplifications to construct a linear molecular beam machine as well as a crossed-atomic and molecular beam machine. The new apparatus measures almost 50 cm in length, with a total laboratory footprint less than 0.25 m{sup 2} for the crossed-atomic and molecular beam machine. We demonstrate the performance of the apparatus by measuring the rotational temperature of nitric oxide from three common molecular beam valves and by observing collisional energy transfer in nitric oxide from a collision with argon.

Jansen, Paul [Vrije Universiteit, 1081 HV Amsterdam (Netherlands); Chandler, David W.; Strecker, Kevin E. [Sandia National Laboratories, Livermore, California 94551 (United States)

2009-08-15T23:59:59.000Z

8

Molecular-beam scattering  

SciTech Connect (OSTI)

The molecular-beam technique has been used in three different experimental arrangements to study a wide range of inter-atomic and molecular forces. Chapter 1 reports results of a low-energy (0.2 kcal/mole) elastic-scattering study of the He-Ar pair potential. The purpose of the study was to accurately characterize the shape of the potential in the well region, by scattering slow He atoms produced by expanding a mixture of He in N/sub 2/ from a cooled nozzle. Chapter 2 contains measurements of the vibrational predissociation spectra and product translational energy for clusters of water, benzene, and ammonia. The experiments show that most of the product energy remains in the internal molecular motions. Chapter 3 presents measurements of the reaction Na + HCl ..-->.. NaCl + H at collision energies of 5.38 and 19.4 kcal/mole. This is the first study to resolve both scattering angle and velocity for the reaction of a short lived (16 nsec) electronic excited state. Descriptions are given of computer programs written to analyze molecular-beam expansions to extract information characterizing their velocity distributions, and to calculate accurate laboratory elastic-scattering differential cross sections accounting for the finite apparatus resolution. Experimental results which attempted to determine the efficiency of optically pumping the Li(2/sup 2/P/sub 3/2/) and Na(3/sup 2/P/sub 3/2/) excited states are given. A simple three-level model for predicting the steady-state fraction of atoms in the excited state is included.

Vernon, M.F.

1983-07-01T23:59:59.000Z

9

Molecular Beam Epitaxy, Multi-source | EMSL  

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

beam epitaxy, is examined using a combination... Self-corrected Sensors Based On Atomic Absorption Spectroscopy For Atom Flux Measurements In Molecular Beam Epitaxy. A...

10

Molecular Beam Epitaxy, Multi-source | EMSL  

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

fundamental insight into water splitting for hydrogen... Self-corrected Sensors Based On Atomic Absorption Spectroscopy For Atom Flux Measurements In Molecular Beam Epitaxy. A...

11

Yuan T. Lee and Molecular Beam Studies  

Office of Scientific and Technical Information (OSTI)

rapidly became a mecca for studies of collision processes. Later, lasers and molecular beams were combined to understand various primary photochemical processes and the...

12

14th international symposium on molecular beams  

SciTech Connect (OSTI)

This report discusses research being conducted with molecular beams. The general topic areas are as follows: Clusters I; reaction dynamics; atomic and molecular spectroscopy; clusters II; new techniques; photodissociation dynamics; and surfaces.

Not Available

1992-01-01T23:59:59.000Z

13

14th international symposium on molecular beams  

SciTech Connect (OSTI)

This report discusses research being conducted with molecular beams. The general topic areas are as follows: Clusters I; reaction dynamics; atomic and molecular spectroscopy; clusters II; new techniques; photodissociation & dynamics; and surfaces.

Not Available

1992-09-01T23:59:59.000Z

14

Yuan T. Lee's Crossed Molecular Beam Experiment  

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

Yuan T. Lee's Crossed Molecular Beam Experiment Yuan T. Lee's Crossed Molecular Beam Experiment Home | Staff | Search | Advisory Committee | User Facilities | Laboratories | Congress | Budget Yuan T. Lee's Crossed Molecular Beam Experiment http://web.archive.org/web/20000902074635/www.er.doe.gov/production/bes/YuanLee_Exp.html (1 of 4)4/7/2006 2:46:13 PM Yuan T. Lee's Crossed Molecular Beam Experiment The above illustration was drawn by Professor Yuan T. Lee, who shared the 1986 Nobel Prize in Chemistry. It shows the design for his crossed molecular beam experiment described in the story beginning on page 27 of "Basic Energy Sciences: Summary of Accomplishments" (DOE/ER-0455P, May 1990); the story is also copied below. The purpose of this experiment was to study the chemical reaction of sodium atoms with oxygen molecules. In the experiment, a beam of sodium atoms (green,

15

Dudley Herschbach: Chemical Reactions and Molecular Beams  

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

Dudley Herschbach: Dudley Herschbach: Chemical Reactions and Molecular Beams Resources with Additional Information Dudley Herschbach Courtesy of Texas A&M University As a co-recipient of the 1986 Nobel Prize in Chemistry, 'Dudley Herschbach was cited for "providing a much more detailed understanding of how chemical reactions take place". Using molecular beams, he studied elementary reactions such as K + CH3I and K + Br2, where it became possible to correlate reaction dynamics with the electronic structures of reactants and products. Exchanges proceeded through a persistent complex that lasted for many rotational periods, with product angular distributions reflecting the degree of reagent entanglement. Later this work was extended to H + Cl2, Cl + HI, halogen substitution reactions with vinyl and allyl halides, as well as such systems as Xe + Ar2 → XeAr + Ar. Herschbach has been a pioneer in the measurement and theoretical interpretation of vector properties of reaction dynamics, a field known as "molecular stereodynamics".

16

Testing atomic mass models with radioactive beams  

SciTech Connect (OSTI)

Significantly increased yields of new or poorly characterized exotic isotopes that lie far from beta-decay stability can be expected when radioactive beams are used to produce these nuclides. Measurements of the masses of these new species are very important. Such measurements are motivated by the general tendency of mass models to diverge from one another upon excursions from the line of beta-stability. Therefore in these regions (where atomic mass data are presently nonexistent or sparse) the models can be tested rigorously to highlight the features that affect the quality of their short-range and long-range extrapolation properties. Selection of systems to study can be guided, in part, by a desire to probe those mass regions where distinctions among mass models are most apparent and where yields of exotic isotopes, produced via radioactive beams, can be optimized. Identification of models in such regions that have good predictive properties will aid materially in guiding the selection of additional experiments which ultimately will provide expansion of the atomic mass database for further refinement of the mass models. 6 refs., 5 figs.

Haustein, P.E.

1989-01-01T23:59:59.000Z

17

Counting molecular-beam grown graphene layers  

SciTech Connect (OSTI)

We have used the ratio of the integrated intensity of graphene's Raman G peak to that of the silicon substrate's first-order optical phonon peak, accurately to determine the number of graphene layers across our molecular-beam (MB) grown graphene films. We find that these results agree well both, with those from our own exfoliated single and few-layer graphene flakes, and with the results of Koh et al.[ACS Nano 5, 269 (2011)]. We hence distinguish regions of single-, bi-, tri-, four-layer, etc., graphene, consecutively, as we scan coarsely across our MB-grown graphene. This is the first, but crucial, step to being able to grow, by such molecular-beam-techniques, a specified number of large-area graphene layers, to order.

Plaut, Annette S. [School of Physics, University of Exeter, Exeter EX4 4QL (United Kingdom)] [School of Physics, University of Exeter, Exeter EX4 4QL (United Kingdom); Wurstbauer, Ulrich [Department of Physics, Columbia University, New York, New York 10027 (United States)] [Department of Physics, Columbia University, New York, New York 10027 (United States); Pinczuk, Aron [Department of Physics, Columbia University, New York, New York 10027 (United States) [Department of Physics, Columbia University, New York, New York 10027 (United States); Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States); Garcia, Jorge M. [MBE Lab, IMM-Instituto de Microelectronica de Madrid (CNM-CSIC), Madrid, E-28760 (Spain)] [MBE Lab, IMM-Instituto de Microelectronica de Madrid (CNM-CSIC), Madrid, E-28760 (Spain); Pfeiffer, Loren N. [Electrical Engineering Department, Princeton University, New Jersey 08544 (United States)] [Electrical Engineering Department, Princeton University, New Jersey 08544 (United States)

2013-06-17T23:59:59.000Z

18

BEAM RELATED SYSTEMATICS IN HIGGS BOSON MASS MEASUREMENT  

E-Print Network [OSTI]

BEAM RELATED SYSTEMATICS IN HIGGS BOSON MASS MEASUREMENT A.RASPEREZA DESY, Notkestrasse 85, D­22607#erential luminosity spectrum measurements and beam energy spread on the precision of the Higgs boson mass measurement possible impact of the beam related systematic errors on the Higgs boson mass measurement is discussed

19

Reactive Collisions in Crossed Molecular Beams  

DOE R&D Accomplishments [OSTI]

The distribution of velocity vectors of reaction products is discussed with emphasis on the restrictions imposed by the conservation laws. The recoil velocity that carries the products away from the center of mass shows how the energy of reaction is divided between internal excitation and translation. Similarly, the angular distributions, as viewed from the center of mass, reflect the partitioning of the total angular momentum between angular momenta of individual molecules and orbital angular momentum associated with their relative motion. Crossed-beam studies of several reactions of the type M + RI yields R + MI are described, where M = K, Rb, Cs, and R = CH{sub 3}, C{sub 3}H{sub 5}, etc. The results show that most of the energy of reaction goes into internal excitation of the products and that the angular distribution is quite anisotropic, with most of the MI recoiling backward (and R forward) with respect to the incoming K beam. (auth)

Herschbach, D. R.

1962-02-00T23:59:59.000Z

20

Molecular beam studies of reaction dynamics  

SciTech Connect (OSTI)

Purpose of this research project is two-fold: (1) to elucidate detailed dynamics of simple elementary reactions which are theoretically important and to unravel the mechanism of complex chemical reactions or photo chemical processes which play an important role in many macroscopic processes and (2) to determine the energetics of polyatomic free radicals using microscopic experimental methods. Most of the information is derived from measurement of the product fragment translational energy and angular distributions using unique molecular beam apparati designed for these purposes.

Lee, Y.T.

1987-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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

BEAM RELATED SYSTEMATICS IN HIGGS BOSON MASS MEASUREMENT  

E-Print Network [OSTI]

BEAM RELATED SYSTEMATICS IN HIGGS BOSON MASS MEASUREMENT A.RASPEREZA DESY, Notkestrasse 85, D-22607 and differential luminosity spectrum measurements and beam energy spread on the precision of the Higgs boson mass such as Higgs boson mass, decay branching fractions and production rate. However, most of these studies did

22

Molecular beam studies of reaction dynamics  

SciTech Connect (OSTI)

The major thrust of this research project is to elucidate detailed dynamics of simple elementary reactions that are theoretically important and to unravel the mechanism of complex chemical reactions or photochemical processes that play important roles in many macroscopic processes. Molecular beams of reactants are used to study individual reactive encounters between molecules or to monitor photodissociation events in a collision-free environment. Most of the information is derived from measurement of the product fragment energy, angular, and state distributions. Recent activities are centered on the mechanisms of elementary chemical reactions involving oxygen atoms with unsaturated hydrocarbons, the dynamics of endothermic substitution reactions, the dependence of the chemical reactivity of electronically excited atoms on the alignment of excited orbitals, the primary photochemical processes of polyatomic molecules, intramolecular energy transfer of chemically activated and locally excited molecules, the energetics of free radicals that are important to combustion processes, the infrared-absorption spectra of carbonium ions and hydrated hydronium ions, and bond-selective photodissociation through electric excitation.

Lee, Y.T. [Lawrence Berkeley Laboratory, CA (United States)

1993-12-01T23:59:59.000Z

23

Molecular beam studies of reaction dynamics  

SciTech Connect (OSTI)

The major thrust of this research project is to elucidate detailed dynamics of simple elementary reactions that are theoretically important and to unravel the mechanism of complex chemical reactions or photochemical processes that play important roles in many macroscopic processes. Molecular beams of reactants are used to study individual reactive encounters between molecules or to monitor photodissociation events in a collision-free environment. Most of the information is derived from measurement of the product fragment energy, angular, and state distributions. Recent activities are centered on the mechanisms of elementary chemical reactions involving oxygen atoms with unsaturated hydrocarbons, the dynamics of endothermic substitution reactions, the dependence of the chemical reactivity of electronically excited atoms on the alignment of excited orbitals, the primary photochemical processes of polyatomic molecules, intramolecular energy transfer of chemically activated and locally excited molecules, the energetics of free radicals that are important to combustion processes, the infrared-absorption spectra of carbonium ions and hydrated hydronium ions, and bond-selective photodissociation through electric excitation.

Lee, Yuan T.

1991-03-01T23:59:59.000Z

24

Apparatus and methods for continuous beam fourier transform mass spectrometry  

DOE Patents [OSTI]

A continuous beam Fourier transform mass spectrometer in which a sample of ions to be analyzed is trapped in a trapping field, and the ions in the range of the mass-to-charge ratios to be analyzed are excited at their characteristic frequencies of motion by a continuous excitation signal. The excited ions in resonant motions generate real or image currents continuously which can be detected and processed to provide a mass spectrum.

McLuckey, Scott A. (Oak Ridge, TN); Goeringer, Douglas E. (Oak Ridge, TN)

2002-01-01T23:59:59.000Z

25

Crossed molecular beam studies of atmospheric chemical reaction dynamics  

SciTech Connect (OSTI)

The dynamics of several elementary chemical reactions that are important in atmospheric chemistry are investigated. The reactive scattering of ground state chlorine or bromine atoms with ozone molecules and ground state chlorine atoms with nitrogen dioxide molecules is studied using a crossed molecular beams apparatus with a rotatable mass spectrometer detector. The Cl + O{sub 3} {yields} ClO + O{sub 2} reaction has been studied at four collision energies ranging from 6 kcal/mole to 32 kcal/mole. The derived product center-of-mass angular and translational energy distributions show that the reaction has a direct reaction mechanism and that there is a strong repulsion on the exit channel. The ClO product is sideways and forward scattered with respect to the Cl atom, and the translational energy release is large. The Cl atom is most likely to attack the terminal oxygen atom of the ozone molecule. The Br + O{sub 3} {yields} ClO + O{sub 2} reaction has been studied at five collision energies ranging from 5 kcal/mole to 26 kcal/mole. The derived product center-of-mass angular and translational energy distributions are quite similar to those in the Cl + O{sub 3} reaction. The Br + O{sub 3} reaction has a direct reaction mechanism similar to that of the Cl + O{sub 3} reaction. The electronic structure of the ozone molecule seems to play the central role in determining the reaction mechanism in atomic radical reactions with the ozone molecule. The Cl + NO{sub 2} {yields} ClO + NO reaction has been studied at three collision energies ranging from 10.6 kcal/mole to 22.4 kcal/mole. The center-of-mass angular distribution has some forward-backward symmetry, and the product translational energy release is quite large. The reaction proceeds through a short-lived complex whose lifetime is less than one rotational period. The experimental results seem to show that the Cl atom mainly attacks the oxygen atom instead of the nitrogen atom of the NO{sub 2} molecule.

Zhang, Jingsong

1993-04-01T23:59:59.000Z

26

Electron Beam Source Molecular Beam Epitaxy of AlxGal?xAs Graded Band Gap Device Structures  

Science Journals Connector (OSTI)

A new method has been developed for the growth of graded band-gap AlxGal?xAs alloys by molecular beam epitaxy which is based upon electron. beam evaporation of the Group III elements ... . The large dynamic respo...

R. J. Malik; A. F. J. Levi; B. F. Levine

1989-01-01T23:59:59.000Z

27

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

28

A molecular beam epitaxy facility for in situ neutron scattering  

SciTech Connect (OSTI)

A molecular beam epitaxy (MBE) facility has been built to enable in situ neutron scattering measurements during growth of epitaxial layers. While retaining the full capabilities of a research MBE chamber, this facility has been optimized for polarized neutron reflectometry measurements. Optimization includes a compact lightweight portable design, a neutron window, controllable magnetic field, deposition across a large 76 mm diameter sample with exceptional flux uniformity, and sample temperatures continuously controllable from 38 to 1375 K. A load lock chamber allows for sample insertion, storage of up to 4 samples, and docking with other facilities. The design and performance of this chamber are described here.

Dura, J. A.; LaRock, J. [NIST Center for Neutron Research, 100 Bureau Dr. MS 6102, Gaithersburg, Maryland 20899 6102 (United States)

2009-07-15T23:59:59.000Z

29

Low-molecular-mass asphaltene compounds from Usa heavy oil  

Science Journals Connector (OSTI)

By the extraction, adsorption chromatography, it has been shown that asphaltene macromolecules from Usa crude oil contain compounds with a relatively low molecular mass represented by normal and branched alkan...

V. P. Sergun; E. Yu. Kovalenko; T. A. Sagachenko; R. S. Min

2014-03-01T23:59:59.000Z

30

Development of mass spectrometry by high energy focused heavy ion beam: MeV SIMS with 8 MeV Cl7+ beam  

Science Journals Connector (OSTI)

Abstract Particle induced X-ray emission (PIXE) at microprobe of Joef Stefan Institute is used to measure two-dimensional quantitative elemental maps of biological tissue. To improve chemical and biological understanding of the processes in vivo, supplementary information about chemical bonding and/or molecular distributions could be obtained by heavy-ion induced molecular desorption and a corresponding mass spectroscopy with Time-Of-Flight (TOF) mass spectrometer. As the method combines the use of heavy focused ions in MeV energy range and TOF Secondary Ion Mass Spectrometry, it is denoted as MeV SIMS. At Joef Stefan Institute, we constructed a linear TOF spectrometer and mount it to our multipurpose nuclear microprobe. A beam of 8MeV 35Cl7+ could be focused to a diameter of better than 3?mנ3?m and pulsed by electrostatic deflection at the high-energy side of accelerator. TOF mass spectrometer incorporates an 1m long drift tube and a double stack microchannel plate (MCP) as a stop detector positioned at the end of the drift path. Secondary ions are focused at MCP using electrostatic cylindrical einzel lens. Time of flight spectra are currently acquired with a single-hit time-to-digital converter. Pulsed ion beam produces a shower of secondary ions that are ejected from positively biased target and accelerated towards MCP. We start our time measurement simultaneously with the start of the beam pulse. Signal of the first ion hitting MCP is used to stop the time measurement. Standard pulses proportional to the time of flight are produced with time to analog converter (TAC) and fed into analog-to-digital converter to obtain a time histogram. To enable efficient detection of desorbed fragments with higher molecular masses, which are of particular interest, we recently implemented a state-of art Field Programmable Gate Array (FPGA)-based multi-hit TOF acquisition. To test the system we used focused 8MeV 35Cl7+ ion beam with pulse length of 180ns. Mass resolution of measured SIMS spectra, dominantly determined by the duration of the beam pulse, is in good agreement with resolution estimated from pulse length. With improved high-voltage switching ability that will enable beam pulses with duration of 50ns, a mass resolution of better than 500 is anticipated.

Luka Jeromel; Zdravko Siketi?; Nina Ogrinc Poto?nik; Primo Vavpeti?; Zdravko Rupnik; Klemen Bu?ar; Primo Pelicon

2014-01-01T23:59:59.000Z

31

Photoconductivity of germanium tin alloys grown by molecular beam epitaxy  

SciTech Connect (OSTI)

Photocurrent spectroscopy was used to measure the infrared absorption of germanium-tin alloys grown by molecular beam epitaxy. To study dependence on Sn composition, the photocurrent was measured at 100 K on alloys of Ge{sub 1-x}Sn{sub x} with atomic percentages of Sn up to 9.8%. The optical absorption coefficient was calculated from the photocurrent, and it was found that the absorption edge and extracted bandgap energy decreased with increasing Sn content. For all Ge{sub 1-x}Sn{sub x} samples, a fundamental bandgap below that of bulk Ge was observed, and a bandgap energy as low as 0.624 eV was found for a Sn percentage of 9.8% at 100 K.

Coppinger, Matthew; Hart, John; Bhargava, Nupur; Kim, Sangcheol; Kolodzey, James [Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716 (United States)] [Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716 (United States)

2013-04-08T23:59:59.000Z

32

Isobar separation by time-of-flight mass spectrometry for low-energy radioactive ion beam facilities  

Science Journals Connector (OSTI)

A multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) system for low-energy radioactive ion beam facilities has been developed, which can be used for (i) isobar separation and (ii) direct mass measurements of very short-lived nuclei with half-lives of about 1ms or longer, and (iii) for identification and diagnosis of the ion beam by mass spectrometry. The system has been designed and simulated, and individual subsystems have been built and characterized experimentally. An injection trap for cooling and bunching of the ion beam has been developed, and cooling times of less than one millisecond have been achieved. The performance of the MR-TOF-MS was characterized using the isobaric doublet of carbon monoxide and nitrogen molecular ions. A mass resolving power of 105 (FWHM) has been obtained even with an uncooled ion population. The separator capabilities of the MR-TOF-MS have been demonstrated by removing either carbon monoxide or nitrogen ions from the beam in a Bradbury-Nielsen Gate after a flight time of 320?s. The separation power achieved is thus at least 7000 (FWHM) and increases for longer time-of-flight. An energy buncher stage has been designed that compresses the energy spread of the beam after the separation and facilitates efficient injection of the selected ions into an accumulation trap prior to transfer of the ions to experiments downstream of the MR-TOF-MS.

Wolfgang R. Pla; Timo Dickel; Ulrich Czok; Hans Geissel; Martin Petrick; Katrin Reinheimer; Christoph Scheidenberger; Mikhail I.Yavor

2008-01-01T23:59:59.000Z

33

Controlled oxygen doping of GaN using plasma assisted molecular-beam epitaxy  

E-Print Network [OSTI]

Controlled oxygen doping of GaN using plasma assisted molecular-beam epitaxy A. J. Ptak, L. J-assisted molecular-beam epitaxy to study the dependence of oxygen incorporation on polarity and oxygen partial pressure. Oxygen incorporates at a rate ten times faster on nitrogen-polar GaN than on the Ga polarity

Myers, Tom

34

Cerenkov emission induced by external beam radiation stimulates molecular fluorescence  

SciTech Connect (OSTI)

Purpose: Cerenkov emission is induced when a charged particle moves faster than the speed of light in a given medium. Both x-ray photons and electrons produce optical Cerenkov photons in everyday radiation therapy of tissue; yet, this phenomenon has never been fully documented. This study quantifies the emissions and also demonstrates that the Cerenkov emission can excite a fluorophore, protoporphyrin IX (PpIX), embedded in biological phantoms. Methods: In this study, Cerenkov emission induced by radiation from a clinical linear accelerator is investigated. Biological mimicking phantoms were irradiated with x-ray photons, with energies of 6 or 18 MV, or electrons at energies 6, 9, 12, 15, or 18 MeV. The Cerenkov emission and the induced molecular fluorescence were detected by a camera or a spectrometer equipped with a fiber optic cable. Results: It is shown that both x-ray photons and electrons, at MeV energies, produce optical Cerenkov photons in tissue mimicking media. Furthermore, we demonstrate that the Cerenkov emission can excite a fluorophore, protoporphyrin IX (PpIX), embedded in biological phantoms. Conclusions: The results here indicate that molecular fluorescence monitoring during external beam radiotherapy is possible.

Axelsson, Johan; Davis, Scott C.; Gladstone, David J.; Pogue, Brian W. [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States); Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03766 (United States); Thayer School of Engineering and Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States)

2011-07-15T23:59:59.000Z

35

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

36

Internal Energy Dependence of Molecular Condensation Coefficients Determined from Molecular Beam Surface Scattering Experiments  

DOE R&D Accomplishments [OSTI]

An experiment was performed which confirms the existence of an internal mode dependence of molecular sticking probabilities for collisions of molecules with a cold surface. The scattering of a velocity selected effusive beam of CCl{sub 4} from a 90 K CC1{sub 4} ice surface has been studied at five translational velocities and for two different internal temperatures. At a surface temperature of 90 K (approx. 99% sticking probability) a four fold increase in reflected intensity was observed for the internally excited (560 K) CC1{sub 4} relative to the room temperature (298 K) CC1{sub 4} at a translational velocity of 2.5 X 10{sup 4} cm/sec. For a surface temperature of 90 K all angular distributions were found to peak 15{sup 0} superspecularly independent of incident velocity.

Sibener, S. J.; Lee, Y. T.

1978-05-00T23:59:59.000Z

37

Molecular-beam epitaxy growth and characterization of mid-infrared quantum cascade laser structures  

Science Journals Connector (OSTI)

The development of molecular-beam epitaxy (MBE) of GaAs/AlGaAs heterostructures, used for fabrication of ~9?m quantum cascade lasers (QCLs), is reported. The X-ray diffractometry (XRD) structural characterization, as an integral part of this process, ... Keywords: GaAs/AlGaAs lasers, Intersubband transitions, Mid-infrared, Molecular-beam epitaxy, Quantum cascade laser, Unipolar devices

Kamil Kosiel; Justyna Kubacka-Traczyk; Piotr Karbownik; Anna Szerling; Jan Muszalski; Maciej Bugajski; Przemek Romanowski; Jaros?aw Gaca; Marek Wjcik

2009-03-01T23:59:59.000Z

38

Molecular Ion Beam Transportation for Low Energy Ion Implantation  

SciTech Connect (OSTI)

A joint research and development of steady state intense boron ion sources for 100's of electron-volt ion implanters has been in progress for the past five years. Current density limitation associated with extracting and transporting low energy ion beams result in lower beam currents that in turn adversely affects the process throughput. The transport channel with electrostatic lenses for decaborane (B{sub 10}H{sub 14}) and carborane (C{sub 2}B{sub 10}H{sub 12}) ion beams transportation was developed and investigated. The significant increase of ion beam intensity at the beam transport channel output is demonstrated. The transport channel simulation, construction and experimental results of ion beam transportation are presented.

Kulevoy, T. V.; Kropachev, G. N.; Seleznev, D. N.; Yakushin, P. E.; Kuibeda, R. P.; Kozlov, A. V.; Koshelev, V. A. [Institute for Theoretical and Experimental Physics, Moscow, 117218 (Russian Federation); Hershcovitch, A.; Johnson, B. M. [Brookhaven National Laboratory, Upton, New York 11973 (United States); Gushenets, V. I.; Oks, E. M. [High Current Electronics Institute Russian Academy of Sciences, Tomsk, 634055 (Russian Federation); Polozov, S. M. [Moscow Engineering Physics Institute, Kashirskoe sh. 31, Moscow, 115409 (Russian Federation); Poole, H. J. [PVI, Oxnard, California 93031-5023 (United States)

2011-01-07T23:59:59.000Z

39

Intermediate and high-mass ion beams from a 10-cm Duopigatron  

Science Journals Connector (OSTI)

Experimental studies of a 10-cm Duopigatron as a source of argon, krypton, and xenon ion beams are reported. Source plasma instabilities ... are examined, and the mass dependence of oscillation frequencies and in...

P. D. Weber; R. M. Gilgenbach

1984-06-01T23:59:59.000Z

40

Characterization of Bacteria by Particle Beam Mass Spectrometry  

Science Journals Connector (OSTI)

...of complex biological material is that of Meuzelaar...instrument, bulk samples of material (>10 Kg) are pyrolyzed...with minimal sample handling, from a naturally occurring...naires Disease (10). MATERIALS AND METHODS Bacteria...FIG. 1. Schematic diagram of particle beam MS...

Mahadeva P. Sinha; Robert M. Platz; Sheldon K. Friedlander; Vincent L. Vilker

1985-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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

Si(001):B gas-source molecular-beam epitaxy: Boron surface segregation and its effect on film growth kinetics  

E-Print Network [OSTI]

The use of disilane (Si2H6) rather than silane (SiH4) for Si 001 gas-source molecular-beam epitaxy GS

Spila, Timothy P.

42

Quantum state specific reactant preparation in a molecular beam by rapid adiabatic passage  

SciTech Connect (OSTI)

Highly efficient preparation of molecules in a specific rovibrationally excited state for gas/surface reactivity measurements is achieved in a molecular beam using tunable infrared (IR) radiation from a single mode continuous wave optical parametric oscillator (cw-OPO). We demonstrate that with appropriate focusing of the IR radiation, molecules in the molecular beam crossing the fixed frequency IR field experience a Doppler tuning that can be adjusted to achieve complete population inversion of a two-level system by rapid adiabatic passage (RAP). A room temperature pyroelectric detector is used to monitor the excited fraction in the molecular beam and the population inversion is detected and quantified using IR bleaching by a second IR-OPO. The second OPO is also used for complete population transfer to an overtone or combination vibration via double resonance excitation using two spatially separated RAP processes.

Chadwick, Helen, E-mail: helen.chadwick@epfl.ch; Hundt, P. Morten; Reijzen, Maarten E. van; Yoder, Bruce L.; Beck, Rainer D. [Laboratoire de Chimie Physique Molculaire, Ecole Polytechnique Fdrale de Lausanne, Lausanne (Switzerland)] [Laboratoire de Chimie Physique Molculaire, Ecole Polytechnique Fdrale de Lausanne, Lausanne (Switzerland)

2014-01-21T23:59:59.000Z

43

Molecular Beam Studies of Hot Atom Chemical Reactions: Reactive Scattering of Energetic Deuterium Atoms  

DOE R&D Accomplishments [OSTI]

A brief review of the application of the crossed molecular beams technique to the study of hot atom chemical reactions in the last twenty years is given. Specific emphasis is placed on recent advances in the use of photolytically produced energetic deuterium atoms in the study of the fundamental elementary reactions D + H{sub 2} -> DH + H and the substitution reaction D + C{sub 2}H{sub 2} -> C{sub 2}HD + H. Recent advances in uv laser and pulsed molecular beam techniques have made the detailed study of hydrogen atom reactions under single collision conditions possible.

Continetti, R. E.; Balko, B. A.; Lee, Y. T.

1989-02-00T23:59:59.000Z

44

Low-temperature grown graphene films by using molecular beam epitaxy  

SciTech Connect (OSTI)

Complete graphene film is prepared by depositing carbon atoms directly on Cu foils in a molecular beam epitaxy chamber at 300 Degree-Sign C. The Raman spectrum of the film has indicated that high-quality few-layer graphene is obtained. With back-gated transistor architecture, the characteristic current modulation of graphene transistors is observed. Following the similar growth procedure, graphitization is observed at room temperature, which is consistent with the molecular dynamics simulations of graphene growth.

Lin, Meng-Yu [Institute of Electronics, National Taiwan University, Taipei, Taiwan (China); Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei, Taiwan (China); Guo, Wei-Ching; Wang, Pro-Yao [Institute of Optoelectronic Sciences, National Taiwan Ocean University, Keelung, Taiwan (China); Wu, Meng-Hsun [College of Photonics, National Chiao-Tung University, Tainan, Taiwan (China); Liu, Te-Huan; Chang, Chien-Cheng [Institute of Applied Mechanics, National Taiwan University, Taipei, Taiwan (China); Pao, Chun-Wei; Lin, Shih-Yen [Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei, Taiwan (China); Lee, Si-Chen [Institute of Electronics, National Taiwan University, Taipei, Taiwan (China)

2012-11-26T23:59:59.000Z

45

Non-adiabatic ab initio molecular dynamics of supersonic beam epitaxy of silicon carbide at room temperature  

E-Print Network [OSTI]

Non-adiabatic ab initio molecular dynamics of supersonic beam epitaxy of silicon carbide at room-adiabatic ab initio molecular dynamics of supersonic beam epitaxy of silicon carbide at room temperature Simone film crystal growth of silicon carbide (SiC), a semiconductor syn- thesized to replace silicon in harsh

Alfè, Dario

46

Crossed Molecular Beam Studies and Dynamics of Decomposition of Chemically Activated Radicals  

DOE R&D Accomplishments [OSTI]

The power of the crossed molecular beams method in the investigation of the dynamics of chemical reactions lies mainly in the direct observation of the consequences of single collisions of well controlled reactant molecules. The primary experimental observations which provide information on reaction dynamics are the measurements of angular and velocity distributions of reaction products.

Lee, Y. T.

1973-09-00T23:59:59.000Z

47

Photodissociation of cyclic compounds in a molecular beam  

SciTech Connect (OSTI)

A discussion on the dynamics and kinematics of photofragmentation-translational spectroscopy is presented, and the results are applied to experimental studies of four cyclic compounds: hexahydro-1,3,5- trinitro-1,3,5-triazine (RDX), s-tetrazine (ST), cyclohexene, (CHN), and 1,4-cyclohexadiene (CHDN). In infrared multiphoton dissociation (IRMPD) of RDX, the dominant primary channel is concerted triple fission to produce three CH/sub 2/N/sub 2/O/sub 2/ fragments which subsequently undergo secondary dissociation. Concerted reactions predominate over simple bond rupture not only in the number of channels, but also in the amount of products. Following /sup 1/B/sub 3u/ reverse arrow /sup 1/A/sub g/ (S/sub 1/ reverse arrow S/sub 0/) or /sup 1/B/sub 2u/ reverse arrow /sup 1/A/sub g/ (248 nm) excitation, ST reverts to the highly vibrationally excited ground electronic state through internal conversion (IC), and then decomposes into 2HCN + N/sub 2/ via concerted triple dissociation. The asymptotic angles between the N/sub 2/ and HCN groups from the center-of-mass of ST are 117.2/degree/ and 114.4/degree/ for S/sub 1/ reverse arrow S/sub 0/ and 248 nm excitation respectively.

Zhao, Xinsheng

1988-11-01T23:59:59.000Z

48

Influence of molecular arrangement and morphology on optical spectra of oligothiophene heterostructures grown by organic molecular-beam deposition  

Science Journals Connector (OSTI)

Heterostructures of quaterthiophene and sexithiophene were grown by organic molecular beam deposition both on fused silica and on potassium acid phthalate (001) single crystals. The influence of both the substrate and the order of deposition on the sample morphology and, in turn, on their optical properties has been investigated. In particular, by changing the deposition conditions, the heterostructures have been found to grow either in an island or in a layer by layer mode. The emission spectra of the latter show the individual quaterthiophene and sexithiophene bands, while the spectra of the island samples are related to effects of the boundary between quaterthiophene and sexithiophene.

S. Tavazzi; D. Besana; A. Borghesi; F. Meinardi; A. Sassella; R. Tubino

2002-04-26T23:59:59.000Z

49

Molecular Beam Epitaxial Growth of GaAs on (631) Oriented Substrates  

SciTech Connect (OSTI)

In this work, we report the study of the homoepitaxial growth of GaAs on (631) oriented substrates by molecular beam epitaxy (MBE). We observed the spontaneous formation of a high density of large scale features on the surface. The hilly like features are elongated towards the [-5, 9, 3] direction. We show the dependence of these structures with the growth conditions and we present the possibility of to create quantum wires structures on this surface.

Cruz Hernandez, Esteban; Rojas Ramirez, Juan-Salvador; Contreras Hernandez, Rocio; Lopez Lopez, Maximo [Physics Department, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 14-740, Mexico D.F., 07000 (Mexico); Pulzara Mora, Alvaro [Universidad Nacional de Colombia - Sede Manizales, A. A. 127 (Colombia); Mendez Garcia, Victor H. [Instituto de Investigacion en Comunicacion Optica, Universidad Autonoma de San Luis Potosi, Av. Karakorum 1470, Lomas 4a Seccion, C.P. 78210, San Luis Potosi (Mexico)

2007-02-09T23:59:59.000Z

50

(In,Mn)As quantum dots: Molecular-beam epitaxy and optical properties  

SciTech Connect (OSTI)

Self-assembled (In,Mn)As quantum dots are synthesized by molecular-beam epitaxy on GaAs (001) substrates. The experimental results obtained by transmission electron microscopy show that doping of the central part of the quantum dots with Mn does not bring about the formation of structural defects. The optical properties of the samples, including those in external magnetic fields, are studied.

Bouravleuv, A. D., E-mail: bour@mail.ioffe.ru; Nevedomskii, V. N. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)] [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Ubyivovk, E. V. [St. Petersburg State University (Russian Federation)] [St. Petersburg State University (Russian Federation); Sapega, V. F. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)] [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Khrebtov, A. I. [St. Petersburg Academic University, Nanotechnology Research and Education Centre (Russian Federation)] [St. Petersburg Academic University, Nanotechnology Research and Education Centre (Russian Federation); Samsonenko, Yu. B.; Cirlin, G. E.; Ustinov, V. M. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)] [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

2013-08-15T23:59:59.000Z

51

Growth of InGaAsP by molecular beam epitaxy  

SciTech Connect (OSTI)

Molecular beam epitaxy has been used to grow good quality films of InGaAsP on InP substrates. The films have been characterized using infrared absorption, electroreflectance, x-ray diffraction, reflection electron diffraction, and Hall measurements. Lattice matching was achieved and room-temperature mobilities up to 4600 cm/sup 2/ V/sup -1/ s/sup -1/ were measured.

Holah, G.D.; Eisele, F.L.; Meeks, E.L.; Cox, N.W.

1982-12-01T23:59:59.000Z

52

Antimony-assisted carbonization of Si(111) with solid source molecular beam epitaxy  

SciTech Connect (OSTI)

The carbonization of an antimony-terminated Si (111) surface in a solid source molecular beam epitaxy system is presented. Reflection high-energy electron diffraction, atomic force microscopy, x-ray photoelectron spectroscopy, and cross-sectional transmission electron microscopy are used to characterize samples grown with and without antimony termination. It is shown that the antimony-terminated surface promotes the formation of thin, smooth and continuous SiC films at a relatively low temperature of 800 C.

Hackley, Justin; Richardson, Christopher J. K. [Laboratory for Physical Sciences, University of Maryland, College Park, Maryland 20740 (United States)] [Laboratory for Physical Sciences, University of Maryland, College Park, Maryland 20740 (United States); Sarney, Wendy L. [U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783 (United States)] [U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783 (United States)

2013-11-15T23:59:59.000Z

53

Molecular Beam Epitaxy on Gas Cluster Ion Beam Prepared GaSb Substrates: Towards Improved Surfaces and Interfaces  

SciTech Connect (OSTI)

A key problem in producing mid-infrared optoelectronic and low-power electronic devices in the GaSb material system is the lack of substrates with appropriate surfaces for epitaxial growth. Chemical mechanical polishing (CMP) of GaSb results in surface damage accompanied by tenacious oxides that do not easily desorb. To overcome this, we have developed a process using gas cluster ion beams (GCIB) to remove surface damage and produce engineered surface oxides. In this paper, we present surface modification results on GaSb substrates using O2-, CF4/O2-, and HBr-GCIB processes. X-ray photoelectron spectroscopy of GCIB produced surface layers showed the presence of mixed Ga- and Sb-oxides, with mostly Ga-oxides at the interface, desorbing at temperatures ranging 530C to 560C. Cross-sectional transmission electron microscopy of molecular beam epitaxy grown GaSb/AlGaSb layers showed that GCIB surfaces yielded smooth defect free substrate to epi transitions as compared to CMP surfaces. Furthermore, HBr-GCIB surfaces exhibited neither dislocation layers nor discernable interfaces, indicating complete oxide desorbtion prior to epigrowth on a clean single crystal template. Atomic force microscopy of GCIB epilayers exhibited smooth surfaces with characteristic step-terrace formations comprising monatomic steps and wide terraces. The HBr-GCIB process can be easily adapted to a large scale manufacturing process for epi-ready GaSb.

Krishnaswami, Kannan; Shivashankar, Vangala; Dauplaise, Helen; Allen, Lisa; Dallas, Gordon; Bakken, Daniel; Bliss, David; Goodhue, William

2008-04-01T23:59:59.000Z

54

Biodegradation of high-molecular-mass heteroatomic components of heavy oil  

Science Journals Connector (OSTI)

Microbial degradation of resins and asphaltenes by indigenous soil microflora has been studied under laboratory conditions on model soil systems. It has been shown that high-molecular-mass heteroatomic compone...

M. A. Kopytov; D. A. Filatov; L. K. Altunina

2014-01-01T23:59:59.000Z

55

Nanostructure formation during ion assisted growth of GaN by molecular beam epitaxy Bentao Cui and P.I. Cohen  

E-Print Network [OSTI]

Nanostructure formation during ion assisted growth of GaN by molecular beam epitaxy Bentao Cui and P.I. Cohen Department of Electrical and Computer Engineering and Department of Chemical Engineering Prairie, MN 55344 (Dated: March 4, 2005) Ion beam assisted molecular beam epitaxy was used to grow Ga

Cohen, Philip I.

56

A portable molecular beam epitaxy system for in situ x-ray investigations at synchrotron beamlines  

SciTech Connect (OSTI)

A portable synchrotron molecular beam epitaxy (MBE) system is designed and applied for in situ investigations. The growth chamber is equipped with all the standard MBE components such as effusion cells with shutters, main shutter, cooling shroud, manipulator, reflection high energy electron diffraction setup, and pressure gauges. The characteristic feature of the system is the beryllium windows which are used for in situ x-ray measurements. An UHV sample transfer case allows in vacuo transfer of samples prepared elsewhere. We describe the system design and demonstrate its performance by investigating the annealing process of buried InGaAs self-organized quantum dots.

Slobodskyy, T. [Institute for Synchrotron Radiation, Karlsruhe Institute of Technology - 76344 Eggenstein-Leopoldshafen (Germany); Institut fuer Angewandte Physik und Zentrum fuer Mikrostrukturforschung, Jungiusstrasse 11, D-20355 Hamburg (Germany); Schroth, P.; Grigoriev, D.; Minkevich, A. A.; Baumbach, T. [Institute for Synchrotron Radiation, Karlsruhe Institute of Technology - 76344 Eggenstein-Leopoldshafen (Germany); Hu, D. Z.; Schaadt, D. M. [Institute for Applied Physics/DFG-Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Institute for Energy Research and Physical Technologies, Technical University Clausthal, Am Stollen 19B, 38640 Goslar (Germany)

2012-10-15T23:59:59.000Z

57

Photoluminescence from GaAs nanodisks fabricated by using combination of neutral beam etching and atomic hydrogen-assisted molecular beam epitaxy regrowth  

SciTech Connect (OSTI)

We have fabricated GaAs nanodisk (ND) structures by using a combination of neutral beam etching process and atomic hydrogen-assisted molecular beam epitaxy regrowth. We have observed clear photoluminescence (PL) emissions from GaAs NDs. The peak energy showed a blueshift due to the quantum confinement in three spatial dimensions, and it agreed with the theoretically estimated transition energy. The PL results also showed that the cap-layer disks act as radiative recombination centers. We have confirmed that the PL emission originates from the GaAs NDs, and our approach is effective for the fabrication of high quality ND structures.

Kaizu, Toshiyuki; Okada, Yoshitaka [Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Japan Science and Technology Agency, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Tamura, Yosuke; Igarashi, Makoto; Hu, Weiguo; Tsukamoto, Rikako [Japan Science and Technology Agency, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Yamashita, Ichiro [Japan Science and Technology Agency, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Samukawa, Seiji [Japan Science and Technology Agency, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); WPI Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

2012-09-10T23:59:59.000Z

58

Real-time reflectance-difference spectroscopy of GaAs molecular beam epitaxy homoepitaxial growth  

SciTech Connect (OSTI)

We report on real time-resolved Reflectance-difference (RD) spectroscopy of GaAs(001) grown by molecular beam epitaxy, with a time-resolution of 500ms per spectrum within the 2.34.0 eV photon energy range. Through the analysis of transient RD spectra we demonstrated that RD line shapes are comprised of two components with different physical origins and determined their evolution during growth. Such components were ascribed to the subsurface strain induced by surface reconstruction and to surface stoichiometry. Results reported in this paper render RD spectroscopy as a powerful tool for the study of fundamental processes during the epitaxial growth of zincblende semiconductors.

Lastras-Martnez, A., E-mail: alm@cactus.iico.uaslp.mx, E-mail: alastras@gmail.com; Ortega-Gallegos, J.; Guevara-Macas, L. E.; Nuez-Olvera, O.; Balderas-Navarro, R. E.; Lastras-Martnez, L. F. [Instituto de Investigacin en Comunicacin Optica, Universidad Autnoma de San Luis Potos, Alvaro Obregn 64, San Luis Potos, SLP 78000 (Mexico); Lastras-Montao, L. A. [IBM T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Lastras-Montao, M. A. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, Santa Barbara, California 93106 (United States)

2014-03-01T23:59:59.000Z

59

Antimony segregation in stressed SiGe heterostructures grown by molecular beam epitaxy  

SciTech Connect (OSTI)

The effects of the growth temperature, composition, and elastic strains in separate layers on the segregation of antimony are studied experimentally for stressed SiGe structures grown by molecular beam epitaxy. It is established that the growth conditions and parameters of the structures exert an interrelated influence on the segregation of Sb: the degree of the influence of the composition and elastic stresses in the SiGe layers on Sb segregation depends on the growth temperature. It is shown that usage of a method previously proposed by us for the selective doping of silicon structures with consideration for the obtained dependences of Sb segregation on the growth conditions and parameters of the SiGe layers makes it possible to form SiGe structures selectively doped with antimony.

Drozdov, M. N.; Novikov, A. V.; Yurasov, D. V., E-mail: Inquisitor@ipm.sci.nnov.ru [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)

2013-11-15T23:59:59.000Z

60

GaNAsP: An intermediate band semiconductor grown by gas-source molecular beam epitaxy  

SciTech Connect (OSTI)

Dilute nitride GaNAsP thin films were grown via a GaAsP metamorphic buffer on GaP(100) substrate with gas-source molecular beam epitaxy. The compositions of this III-V-V-V compound were determined by channeling Rutherford backscattering spectroscopy and nuclear reaction analysis. Photoreflectance shows two distinctive transitions from the valence band to the split conduction bands due to N incorporation. Photoluminescence and optical absorption show the fundamental bandgap of Ga(N)AsP is largely tailored by the small amount of N. The observed multiband characteristics and the bandgap tunability of GaNAsP are two merits that fit into the intermediate-band solar cell roadmap, and GaNAsP of high crystal quality provides a strong candidate for intermediate band solar cell materials.

Kuang, Y. J. [Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States)] [Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States); Yu, K. M.; Walukiewicz, W. [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Kudrawiec, R. [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States) [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Institute of Physics, Wroclaw University of Technology, Wybrzeze, Wyspianskiego 27, 50-370 Wroclaw (Poland); Luce, A. V. [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States) [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Ting, M. [Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States)] [Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States); Tu, C. W. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States)] [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States)

2013-03-18T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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

Intense terahertz emission from molecular beam epitaxy-grown GaAs/GaSb(001)  

SciTech Connect (OSTI)

Intense terahertz (THz) electromagnetic wave emission was observed in undoped GaAs thin films deposited on (100) n-GaSb substrates via molecular beam epitaxy. GaAs/n-GaSb heterostructures were found to be viable THz sources having signal amplitude 75% that of bulk p-InAs. The GaAs films were grown by interruption method during the growth initiation and using various metamorphic buffer layers. Reciprocal space maps revealed that the GaAs epilayers are tensile relaxed. Defects at the i-GaAs/n-GaSb interface were confirmed by scanning electron microscope images. Band calculations were performed to infer the depletion region and electric field at the i-GaAs/n-GaSb and the air-GaAs interfaces. However, the resulting band calculations were found to be insufficient to explain the THz emission. The enhanced THz emission is currently attributed to a piezoelectric field induced by incoherent strain and defects.

Sadia, Cyril P.; Laganapan, Aleena Maria; Agatha Tumanguil, Mae; Estacio, Elmer; Somintac, Armando; Salvador, Arnel [National Institute of Physics, University of the Philippines Diliman, Quezon City 1101 (Philippines); Que, Christopher T. [Physics Department, De La Salle University, 2401 Taft Avenue, Manila 1004 (Philippines); Yamamoto, Kohji; Tani, Masahiko [Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507 (Japan)

2012-12-15T23:59:59.000Z

62

Interband transitions in molecular?beam?epitaxial Al x Ga1?x As/GaAs  

Science Journals Connector (OSTI)

Interband transition energies for Al x Ga1?x As layers grown by molecular?beam epitaxy(MBE) techniques have been determined using the electrolyte electroreflectance (EER) technique. The observed data fit quadratic relations for E 0 E 0+?0 E 1 and E 1+?1 to describe variations of energy with composition. Although the x values were not accurately known the internal consistency of the data is excellent. Given a single bowing parameter we show that accurate values of x can be determined. The EER technique can provide x values with an accuracy better than 0.02 and information on changes in x as small as 0.002. It is thus ideally suited for studying MBE materials.

J. L. Aubel; U. K. Reddy; S. Sundaram; W. T. Beard; James Comas

1985-01-01T23:59:59.000Z

63

Germanium diffusion during HfO{sub 2} growth on Ge by molecular beam epitaxy  

SciTech Connect (OSTI)

The authors study the Ge diffusion during HfO{sub 2} growth by molecular beam epitaxy on differently in situ prepared germanium substrates and at different growth temperatures. While HfO{sub 2} layers grown directly on Ge do not show any germanium contamination, oxygen rich interfacial layers such as GeO{sub x} or GeO{sub x}N{sub y} partly dissolve into the HfO{sub 2} layer, giving rise to high Ge contamination (from 1% to 10%). The use of nitridated interfacial layers does not prevent Ge diffusion into the HfO{sub 2} during the growth process because of the high oxygen content present in the nitridated germanium layer.

Ferrari, S.; Spiga, S.; Wiemer, C.; Fanciulli, M.; Dimoulas, A. [Laboratorio MDM-INFM-CNR, Via Olivetti, 2 Agrate Brianza, Milano 20041 (Italy); MBE Laboratory, Institute of Materials Science, DEMOKRITOS National Center for Scientific Research, 153 10 Athens (Greece)

2006-09-18T23:59:59.000Z

64

Infrared electroluminescence from GeSn heterojunction diodes grown by molecular beam epitaxy  

SciTech Connect (OSTI)

Infrared electroluminescence was observed from GeSn/Ge p-n heterojunction diodes with 8% Sn, grown by molecular beam epitaxy. The GeSn layers were boron doped, compressively strained, and pseudomorphic on Ge substrates. Spectral measurements indicated an emission peak at 0.57 eV, about 50 meV wide, increasing in intensity with applied pulsed current, and with reducing device temperatures. The total integrated emitted power from a single edge facet was 54 {mu}W at an applied peak current of 100 mA at 100 K. These results suggest that GeSn-based materials maybe useful for practical light emitting diodes operating in the infrared wavelength range near 2 {mu}m.

Gupta, Jay Prakash; Bhargava, Nupur; Kim, Sangcheol; Kolodzey, James [Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716 (United States)] [Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716 (United States); Adam, Thomas [Nanofab, University of Albany, SUNY, Albany, New York 12203 (United States)] [Nanofab, University of Albany, SUNY, Albany, New York 12203 (United States)

2013-06-24T23:59:59.000Z

65

Lattice constant and substitutional composition of GeSn alloys grown by molecular beam epitaxy  

SciTech Connect (OSTI)

Single crystal epitaxial Ge{sub 1?x}Sn{sub x} alloys with atomic fractions of tin up to x = 0.145 were grown by solid source molecular beam epitaxy on Ge (001) substrates. The Ge{sub 1?x}Sn{sub x} alloys formed high quality, coherent, strained layers at growth temperatures below 250 C, as shown by high resolution X-ray diffraction. The amount of Sn that was on lattice sites, as determined by Rutherford backscattering spectrometry channeling, was found to be above 90% substitutional in all alloys. The degree of strain and the dependence of the effective unstrained bulk lattice constant of Ge{sub 1?x}Sn{sub x} alloys versus the composition of Sn have been determined.

Bhargava, Nupur; Coppinger, Matthew; Prakash Gupta, Jay; Kolodzey, James [Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716 (United States)] [Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716 (United States); Wielunski, Leszek [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 (United States)] [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 (United States)

2013-07-22T23:59:59.000Z

66

Positron annihilation studies of defects in molecular beam epitaxy grown III-V layers  

SciTech Connect (OSTI)

A summary of recent positron annihilation experiments on molecular beam epitaxy (MBE) grown III-V layers is Presented. Variable energy positron beam measurements on Al{sub 0.32}Ga{sub 0.68}As undoped and Si doped have been completed. Positron trapping at a open volume defect in Al{sub 0.32}Ga{sub 0.68}:Si for temperatures from 300 to 25 K in the dark was observed. The positron trap was lost after 1.3 eV illumination at 25K. These results indicate an open volume defect is associated with the local structure of the deep donor state of the DX center. Stability of MBE GaAs to thermal annealing war, investigated over the temperature range of 230 to 700{degrees}C, Proximity wafer furnace anneals in flowing argon were used, Samples grown above 450{degrees}C were shown to be stable but for sample below this temperature an anneal induced vacancy related defect was produced for anneals between 400 and 500{degrees}C. The nature of the defect was shown to be different for material grown at 350 and 230{degrees}C. Activation energies of 2.5 eV to 2.3 eV were obtained from isochronal anneal experiments for samples grown at 350 and 230{degrees}C, respectively.

Umlor, M.T.; Keeble, D.J. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Physics; Asoka-Kumar, P.; Lynn, K.G. [Brookhaven National Lab., Upton, NY (United States); Cooke, P.W. [Geo-Centers, Inc., Eatontown, NJ (United States). Fort Monmouth Operation

1994-08-01T23:59:59.000Z

67

Molecular Beam and Surface Science Studies of Heterogeneous Reaction Kinetics Including Combustion Dynamics. Final Technical Report.  

SciTech Connect (OSTI)

This research program examined the heterogeneous reaction kinetics and reaction dynamics of surface chemical processes which are of direct relevance to efficient energy production, condensed phase reactions, and mateials growth including nanoscience objectives. We have had several notable scientific and technical successes. Illustrative highlights include: (1) a thorough study of how one can efficiently produce synthesis gas (SynGas) at relatively low Rh(111) catalyst temperatures via the reaction CH{sub4}+1/2 O{sub2} {r_arrow} CO+2H{sub2}. In these studies methane activation is accomplished utilizing high-kinetic energy reagents generated via supersonic molecular beams, (2) experiments which have incisively probed the partial oxidation chemistry of adsorbed 1- and 2- butene on Rh and ice, as well as partial oxidation of propene on Au; (3) investigation of structural changes which occur to the reconstructed (23x{radical}3)-Au(111) surface upon exposure to atomic oxygen, (4) a combined experimental and theoretical examination of the fundamental atomic-level rules which govern defect minimization during the formation of self-organizing stepped nanostructures, (5) the use of these relatively defect-free nanotemplates for growing silicon nanowires having atomically-dimensioned widths, (6) a combined scanning probe and atomic beam scattering study of how the presence of self-assembling organic overlayers interact with metallic supports substrates - this work hs led to revision of the currently held view of how such adsorbates reconfigure surface structure at the atomic level, (7) an inelastic He atom scattering study in which we examined the effect of chain length on the low-energy vibrations of alkanethiol striped phase self-assembled monolayers on Au(111), yielding information on the forces that govern interfacial self-assembly, (8) a study of the vibrational properties of disordered films of SF{sub6} adsorbed on Au(111), and (9) a study of the activated chemistry and photochemistry of NO on NiO/Ni. Innovative STM and molecular beam instrumentation has been fabricated to enable this program.

Sibener, S. J.

2006-06-23T23:59:59.000Z

68

Molecular beam epitaxial growth of Si1?xGex/Si pseudomorphic layers using disilane and germanium  

Science Journals Connector (OSTI)

Molecular beam epitaxial growth of pseudomorphic Si1?xGex/Si layers using disilane (Si2H6) and elemental germanium has been studied for the first time. It is found that at a fixed flow rate of Si2H6, the germaniu...

S. H. Li; P. K. Bhattacharya; R. Malik; E. Gulari

1993-07-01T23:59:59.000Z

69

A Comparison of Magnesium and Beryllium Acceptors in GaN Grown by rf-Plasma Assisted Molecular Beam Epitaxy  

E-Print Network [OSTI]

A Comparison of Magnesium and Beryllium Acceptors in GaN Grown by rf-Plasma Assisted Molecular Beam Evans and Associates, Sunnyvale, CA 94086 ABSTRACT Step-doped structures of both magnesium and beryllium activation energy of approximately 100 meV. INTRODUCTION While magnesium is currently the most

Myers, Tom

70

Radiation environment simulations at the Tevatron, studies of the beam profile and measurement of the Bc meson mass  

SciTech Connect (OSTI)

The description of a computer simulation of the CDF detector at Fermilab and the adjacent accelerator parts is detailed, with MARS calculations of the radiation background in various elements of the model due to the collision of beams and machine-related losses. Three components of beam halo formation are simulated for the determination of the principal source of radiation background in CDF due to beam losses. The effect of a collimator as a protection for the detector is studied. The simulation results are compared with data taken by a CDF group. Studies of a 150 GeV Tevatron proton beam are performed to investigate the transverse diffusion growth and distribution. A technique of collimator scan is used to scrape the beam under various experimental conditions, and computer programs are written for the beam reconstruction. An average beam halo growth speed is given and the potential of beam tail reconstruction using the collimator scan is evaluated. A particle physics analysis is conducted in order to detect the B{sub c} {yields} J/{psi}{pi} decay signal with the CDF Run II detector in 360 pb{sup -1} of data. The cut variables and an optimization method to determine their values are presented along with a criterion for the detection threshold of the signal. The mass of the B{sub c} meson is measured with an evaluation of the significance of the signal.

Nicolas, Ludovic Y.; /Glasgow U.

2005-09-01T23:59:59.000Z

71

Direct determination of the adiabatic ionization energy of NO2 as measured by guided ion-beam mass spectrometry  

E-Print Network [OSTI]

Direct determination of the adiabatic ionization energy of NO2 as measured by guided ion-beam mass the past 60 years the value for the ionization energy (IE) of nitrogen dioxide has been measured many times, Utah 84112 (Received 16 April 1992; accepted 4 May 1992) The adiabatic ionization energy (IE) of NOa

Clemmer, David E.

72

Origin of Reflection High-Energy Electron-Diffraction Intensity Oscillations during Molecular-Beam Epitaxy: A Computational Modeling Approach  

Science Journals Connector (OSTI)

Temporal oscillations in the specular beam of reflection high-energy electron diffraction (RHEED) provide the primary method of monitoring growth by molecular-beam epitaxy. We develop a model to investigate the origin of these oscillations with which, by monitoring the step density of a growing sample, we are able to reproduce all of the principal features of recent RHEED measurements. Our work demonstrates the considerable advantages in adoption of simple monatomic growth models instead of the complex models used for studying the growth of compound semiconductors.

Shaun Clarke and Dimitri D. Vvedensky

1987-05-25T23:59:59.000Z

73

Lattice-registered growth of GaSb on Si (211) with molecular beam epitaxy  

SciTech Connect (OSTI)

A GaSb film was grown on a Si(211) substrate using molecular beam epitaxy indicating full lattice relaxation as well as full lattice registration and dislocation-free growth in the plane perpendicular to the [01 - 1]-direction. Heteroepitaxy of GaSb on a Si(211) substrate is dominated by numerous first order and multiple higher order micro-twins. The atomic-resolved structural study of GaSb films by high-angle annular dark-field scanning transmission electron microscopy reveals that slight tilt, along with twinning, favors the lattice registry to Si(211) substrates. Preferential bonding of impinging Ga and Sb atoms at the interface due to two distinctive bonding sites on the Si(211) surface enables growth that is sublattice-ordered and free of anti-phase boundaries. The role of the substrate orientation on the strain distribution of GaSb epilayers is further elucidated by investigating the local change in the lattice parameter using the geometric phase analysis method and hence effectiveness of the lattice tilting in reducing the interfacial strain was confirmed further.

Hosseini Vajargah, S.; Botton, G. A. [Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7 (Canada); Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Canadian Centre for Electron Microscopy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Ghanad-Tavakoli, S. [Centre for Emerging Device Technologies, McMaster University, Hamilton, Ontario L8S 4L7 (Canada); Preston, J. S.; Kleiman, R. N. [Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Centre for Emerging Device Technologies, McMaster University, Hamilton, Ontario L8S 4L7 (Canada); Department of Engineering Physics, McMaster University, Hamilton, Ontario L8S 4L7 (Canada)

2012-11-01T23:59:59.000Z

74

Dependence of the Mg-related acceptor ionization energy with the acceptor concentration in p-type GaN layers grown by molecular beam epitaxy  

SciTech Connect (OSTI)

Hall effect and capacitance-voltage C(V) measurements were performed on p-type GaN:Mg layers grown on GaN templates by molecular beam epitaxy with a high range of Mg-doping concentrations. The free hole density and the effective dopant concentration N{sub A}-N{sub D} as a function of magnesium incorporation measured by secondary ion mass spectroscopy clearly reveal both a magnesium doping efficiency up to 90% and a strong dependence of the acceptor ionization energy Ea with the acceptor concentration N{sub A}. These experimental observations highlight an isolated acceptor binding energy of 245{+-}25 meV compatible, at high acceptor concentration, with the achievement of p-type GaN:Mg layers with a hole concentration at room temperature close to 10{sup 19} cm{sup -3}.

Brochen, Stephane; Brault, Julien; Chenot, Sebastien; Dussaigne, Amelie; Leroux, Mathieu; Damilano, Benjamin [CNRS-CRHEA, Rue Bernard Gregory, F-06560 Valbonne (France)

2013-07-15T23:59:59.000Z

75

Chlorine doping of cubic CdS and ZnS grown by compound source molecular-beam epitaxy  

Science Journals Connector (OSTI)

We report on the chlorine doping of ZnS and CdS grown by compound source molecular-beam epitaxy. The maximum free electron concentrations achieved were 11018 and 81019cm?3, respectively. The conductivity of the cubic CdS epilayers turned out to be anisotropic with respect to the ?110? crystallographic directions due to an anisotropic lattice defect structure.

M Grn; A Storzum; M Hetterich; A Kamilli; W Send; Th Walter; C Klingshirn

1999-01-01T23:59:59.000Z

76

Self-corrected Sensors Based On Atomic Absorption Spectroscopy For Atom Flux Measurements In Molecular Beam Epitaxy  

SciTech Connect (OSTI)

A high sensitivity atom flux sensor based on atomic absorption spectroscopy has been designed and implemented to control electron beam evaporators and effusion cells in a molecular beam epitaxy system. Using a high-resolution spectrometer and a two-dimensional charge coupled device (CCD) detector in a double-beam configuration, we employ a non-resonant line or a resonant line with lower absorbance from the same hollow cathode lamp as the reference for nearly perfect background correction and baseline drift removal. This setup also significantly shortens the warm-up time needed compared to other sensor technologies and drastically reduces the noise coming from the surrounding environment. In addition, the high-resolution spectrometer allows the most sensitive resonant line to be isolated and used to provide excellent signal-to-noise ratio.

Du, Yingge; Droubay, Timothy C.; Liyu, Andrey V.; Li, Guosheng; Chambers, Scott A.

2014-04-24T23:59:59.000Z

77

Atom probe tomography characterisation of a laser diode structure grown by molecular beam epitaxy  

SciTech Connect (OSTI)

Atom probe tomography (APT) has been used to achieve three-dimensional characterization of a III-nitride laser diode (LD) structure grown by molecular beam epitaxy (MBE). Four APT data sets have been obtained, with fields of view up to 400 nm in depth and 120 nm in diameter. These data sets contain material from the InGaN quantum well (QW) active region, as well as the surrounding p- and n-doped waveguide and cladding layers, enabling comprehensive study of the structure and composition of the LD structure. Two regions of the same sample, with different average indium contents (18% and 16%) in the QW region, were studied. The APT data are shown to provide easy access to the p-type dopant levels, and the composition of a thin AlGaN barrier layer. Next, the distribution of indium within the InGaN QW was analyzed, to assess any possible inhomogeneity of the distribution of indium (''indium clustering''). No evidence for a statistically significant deviation from a random distribution was found, indicating that these MBE-grown InGaN QWs do not require indium clusters for carrier localization. However, the APT data show steps in the QW interfaces, leading to well-width fluctuations, which may act to localize carriers. Additionally, the unexpected presence of a small amount (x = 0.005) of indium in a layer grown intentionally as GaN was revealed. Finally, the same statistical method applied to the QW was used to show that the indium distribution within a thick InGaN waveguide layer in the n-doped region did not show any deviation from randomness.

Bennett, Samantha E.; Humphreys, Colin J.; Oliver, Rachel A. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ (United Kingdom); Smeeton, Tim M.; Hooper, Stewart E.; Heffernan, Jonathan [Sharp Laboratories of Europe Limited, Edmund Halley Road, Oxford Science Park, Oxford, OX4 4GB (United Kingdom); Saxey, David W.; Smith, George D. W. [Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH (United Kingdom)

2012-03-01T23:59:59.000Z

78

Impact of substrate temperature on the incorporation of carbon-related defects and mechanism for semi-insulating behavior in GaN grown by molecular beam epitaxy  

E-Print Network [OSTI]

B 22, 1145 ?2004?. A. Armstrong, A. R. Arehart, D. Green, U.San Diego, 1992?. A. Armstrong, A. R. Arehart, and S. A.molecular beam epitaxy A. Armstrong Department of Electrical

Armstrong, A; Poblenz, C; Green, D S; Mishra, U K; Speck, J S; Ringel, S A

2006-01-01T23:59:59.000Z

79

Molecular-beam epitaxy growth of strontium thiogallate T. Yang, B. K. Wagner, M. Chaichimansour, W. Park, Z. L. Wang,a)  

E-Print Network [OSTI]

Molecular-beam epitaxy growth of strontium thiogallate T. Yang, B. K. Wagner, M. Chaichimansour, W-beam epitaxy growth and characterization of cerium doped strontium thiogallate SrGa2S4:Ce thin film phosphors growth of cerium doped strontium thiogallate on quartz substrates was first reported in 1994.3 Here we

Wang, Zhong L.

80

Peculiarly strong room-temperature ferromagnetism from low Mn-doping in ZnO grown by molecular beam epitaxy  

SciTech Connect (OSTI)

Strong room-temperature ferromagnetism is demonstrated in single crystalline Mn-doped ZnO thin films grown by molecular beam epitaxy. Very low Mn doping concentration is investigated, and the measured magnetic moment is much larger than what is expected for an isolated ion based on Hund's rules. The ferromagnetic behavior evolves with Mn concentration. Both magnetic anisotropy and anomalous Hall effect confirm the intrinsic nature of ferromagnetism. While the Mn dopant plays a crucial role, another entity in the system is needed to explain the observed large magnetic moments.

Zuo Zheng; Morshed, Muhammad; Liu Jianlin [Quantum Structures Laboratory, Department of Electrical Engineering, University of California at Riverside, Riverside, California 92521 (United States); Beyermann, W. P. [Department of Physics and Astronomy, University of California at Riverside, Riverside, California 92521 (United States); Zheng Jianguo [Laboratory for Electron and X-ray Instrumentation, California Institute for Telecommunications and Information Technology, University of California Irvine, Irvine, California 92697 (United States); Xin Yan [NHMFL, Florida State University, 1800 E. Paul Dirac Dr., Tallahassee, FL 32310-3706 (United States)

2013-03-15T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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

Chirped-pulse manipulated carrier dynamics in low-temperature molecular-beam-epitaxy grown GaAs  

SciTech Connect (OSTI)

Chirped pulse controlled carrier dynamics in low-temperature molecular-beam-epitaxy grown GaAs are investigated by degenerate pump-probe technique. Varying the chirped condition of excited pulse from negative to positive increases the carrier relaxation time so as to modify the dispersion and reshape current pulse in time domain. The spectral dependence of carrier dynamics is analytically derived and explained by Shockley-Read Hall model. This observation enables the new feasibility of controlling carrier dynamics in ultrafast optical devices via the chirped pulse excitations.

Lee, Chao-Kuei, E-mail: chuckcklee@yahoo.com [Department of Photonics, National Sun-Yat-Sen University, Kaohsiung 80400, Taiwan (China); Lin, Yuan-Yao [Department of Electrical Engineering, Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30010, Taiwan (China); Lin, Sung-Hui [Department of Photonics, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Lin, Gong-Ru [Department of Electrical Engineering, Graduate Institute of Photonics and Optoelectronics, National Taiwan University, No. 1, Roosevelt Road, Sec. 4, Taipei 10617, Taiwan (China); Pan, Ci-Ling [Department of Photonics, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Department of Physics, National Tsing Hwa University, Hsinchu 30010, Taiwan (China)

2014-04-28T23:59:59.000Z

82

Elastic effects and phase segregation during the growth of thin alloy layers by molecular-beam epitaxy  

Science Journals Connector (OSTI)

We explore the effects of stress and strain on the composition modulations seen during the growth of thin solid films by molecular-beam epitaxy when phase separation is the driving mechanism for the concentration inhomogeneity. A top view of the growing thin film shows lamellar and hexagonal patterns of phase-separated domains, the elastic effects being directly responsible for the appearance of the hexagonal order. We find that in the lamellar regime, elastically deformed lamellae are separated by undeformed interfaces, while in the droplet phase, the soft component is deformed and wraps the hard component. We also discuss the effects of crystal anisotropy in our system.

Franois Lonard and Rashmi C. Desai

1997-08-15T23:59:59.000Z

83

Inhomogeneous Si-doping of gold-seeded InAs nanowires grown by molecular beam epitaxy  

SciTech Connect (OSTI)

We have investigated in situ Si doping of InAs nanowires grown by molecular beam epitaxy from gold seeds. The effectiveness of n-type doping is confirmed by electrical measurements showing an increase of the electron density with the Si flux. We also observe an increase of the electron density along the nanowires from the tip to the base, attributed to the dopant incorporation on the nanowire facets whereas no detectable incorporation occurs through the seed. Furthermore, the Si incorporation strongly influences the lateral growth of the nanowires without giving rise to significant tapering, revealing the complex interplay between axial and lateral growth.

Rolland, Chloe; Coinon, Christophe; Wallart, Xavier; Leturcq, Renaud [Institute of Electronics Microelectronics and Nanotechnology, UMR CNRS 8520, ISEN Department, Avenue Poincare, CS60069, 59652 Villeneuve d'Ascq Cedex (France)] [Institute of Electronics Microelectronics and Nanotechnology, UMR CNRS 8520, ISEN Department, Avenue Poincare, CS60069, 59652 Villeneuve d'Ascq Cedex (France); Caroff, Philippe [Institute of Electronics Microelectronics and Nanotechnology, UMR CNRS 8520, ISEN Department, Avenue Poincare, CS60069, 59652 Villeneuve d'Ascq Cedex (France) [Institute of Electronics Microelectronics and Nanotechnology, UMR CNRS 8520, ISEN Department, Avenue Poincare, CS60069, 59652 Villeneuve d'Ascq Cedex (France); Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia)

2013-06-03T23:59:59.000Z

84

Physical properties and band structure of reactive molecular beam epitaxy grown oxygen engineered HfO{sub 2{+-}x}  

SciTech Connect (OSTI)

We have conducted a detailed thin film growth structure of oxygen engineered monoclinic HfO{sub 2{+-}x} grown by reactive molecular beam epitaxy. The oxidation conditions induce a switching between (111) and (002) texture of hafnium oxide. The band gap of oxygen deficient hafnia decreases with increasing amount of oxygen vacancies by more than 1 eV. For high oxygen vacancy concentrations, defect bands form inside the band gap that induce optical transitions and p-type conductivity. The resistivity changes by several orders of magnitude as a function of oxidation conditions. Oxygen vacancies do not give rise to ferromagnetic behavior.

Hildebrandt, Erwin; Kurian, Jose; Alff, Lambert [Institute of Materials Science, Technische Universitaet Darmstadt, 64287 Darmstadt (Germany)

2012-12-01T23:59:59.000Z

85

Optical properties of strain-free AlN nanowires grown by molecular beam epitaxy on Si substrates  

SciTech Connect (OSTI)

The optical properties of catalyst-free AlN nanowires grown on Si substrates by molecular beam epitaxy were investigated. Such nanowires are nearly free of strain, with strong free exciton emission measured at room temperature. The photoluminescence intensity is significantly enhanced, compared to previously reported AlN epilayer. Moreover, the presence of phonon replicas with an energy separation of ?100?meV was identified to be associated with the surface-optical phonon rather than the commonly reported longitudinal-optical phonon, which is further supported by the micro-Raman scattering experiments.

Wang, Q.; Zhao, S.; Connie, A. T.; Shih, I.; Mi, Z., E-mail: zetian.mi@mcgill.ca [Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec H3A 0E9 (Canada); Gonzalez, T.; Andrews, M. P. [Department of Chemistry, McGill University, 801 Sherbrooke St West, Montreal, Quebec H3A 0B8 (Canada); Du, X. Z.; Lin, J. Y.; Jiang, H. X. [Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)

2014-06-02T23:59:59.000Z

86

Non-adiabatic ab initio molecular dynamics of supersonic beam epitaxy of silicon carbide at room temperature  

SciTech Connect (OSTI)

In this work, we investigate the processes leading to the room-temperature growth of silicon carbide thin films by supersonic molecular beam epitaxy technique. We present experimental data showing that the collision of fullerene on a silicon surface induces strong chemical-physical perturbations and, for sufficient velocity, disruption of molecular bonds, and cage breaking with formation of nanostructures with different stoichiometric character. We show that in these out-of-equilibrium conditions, it is necessary to go beyond the standard implementations of density functional theory, as ab initio methods based on the Born-Oppenheimer approximation fail to capture the excited-state dynamics. In particular, we analyse the Si-C{sub 60} collision within the non-adiabatic nuclear dynamics framework, where stochastic hops occur between adiabatic surfaces calculated with time-dependent density functional theory. This theoretical description of the C{sub 60} impact on the Si surface is in good agreement with our experimental findings.

Taioli, Simone [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Department of Physics, University of Trento, Trento (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Perugia (Italy); Department of Chemistry, University of Bologna, Bologna (Italy); Garberoglio, Giovanni [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Simonucci, Stefano [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Perugia (Italy); Department of Physics, University of Camerino, Camerino (Italy); Beccara, Silvio a [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Department of Physics, University of Trento, Trento (Italy); Aversa, Lucrezia [Institute of Materials for Electronics and Magnetism, IMEM-CNR, Trento (Italy); Nardi, Marco [Institute of Materials for Electronics and Magnetism, IMEM-CNR, Trento (Italy); Institut fuer Physik, Humboldt-Universitaet zu Berlin, Berlin (Germany); Verucchi, Roberto [Institute of Materials for Electronics and Magnetism, FBK-CNR, Trento (Italy); Iannotta, Salvatore [Institute of Materials for Electronics and Magnetism, IMEM-CNR, Parma (Italy); Dapor, Maurizio [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Department of Materials Engineering and Industrial Technologies, University of Trento, Trento (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Padova (Italy); and others

2013-01-28T23:59:59.000Z

87

Molecular beam mass spectrometry with tunable vacuum ultraviolet (VUV) synchrotron radiation  

E-Print Network [OSTI]

and electronic structure calculations. Physical Chemistrycomparison with electronic structure calculations[11, 12].and calculations and in turn, explain in detail the electronic

Golan, Amir

2014-01-01T23:59:59.000Z

88

Molecular beam mass spectrometry with tunable vacuum ultraviolet (VUV) synchrotron radiation  

E-Print Network [OSTI]

Fundamental studies of photoionization processes of biomolecules provide information about electronic

Golan, Amir

2014-01-01T23:59:59.000Z

89

Compact time-of-flight mass spectrometer  

SciTech Connect (OSTI)

This paper describes a time-of-flight mass spectrometer developed for measuring the parameters of a pulsed hydrogen beam. The duration of an electron-beam current pulse in the ionizer of the mass spectrometer can be varied within 2-20 usec, the pulse electron current is 0.6 mA, and the electron energy is 250 eV. The time resolution of the mass spectrometer is determined by the repetition period of the electron-beam current pulses and is 40 usec. The mass spectrometer has 100% transmission in the direction of motion of molecular-beam particles. The dimension of the mass spectrometer is 7 cm in this direction. The mass resolution is sufficient for determination of the composition of the hydrogen beam.

Belov, A.S.; Kubalov, S.A.; Kuzik, V.F.; Yakushev, V.P.

1986-02-01T23:59:59.000Z

90

Molecular Outflows in Low- and High-Mass Star Forming Regions  

E-Print Network [OSTI]

We review the known properties of molecular outflows from low- and high-mass young stars. General trends among outflows are identified, and the most recent studies on the morphology, kinematics, energetics, and evolution of molecular outflows are discussed, focusing on results from high-resolution millimeter observations. We review the existing four broad classes of outflow models and compare numerical simulations with the observational data. A single class of models cannot explain the range of morphological and kinematic properties that are observed, and we propose a possible solution. The impact of outflows on their cloud is examined, and we review how outflows can disrupt their surrounding environment, through the clearing of gas and the injection of momentum and energy onto the gas at distances from their powering sources from about 0.01 to a few pc. We also discuss the effects of shock-induced chemical processes on the ambient medium, and how these processes may act as a chemical clock to date outflows. Lastly, future outflow research with existing and planned millimeter and submillimeter instruments is presented.

Hector G. Arce; Debra Shepherd; Frederic Gueth; Chin-Fei Lee; Rafael Bachiller; Alexander Rosen; Henrik Beuther

2006-03-03T23:59:59.000Z

91

High-resolution imaging of velocity-controlled molecular collisions using counterpropagating beams  

E-Print Network [OSTI]

We present ultrahigh-resolution measurements of state-to-state inelastic differential cross sections for NO-Ne and NO-Ar collisions, obtained by combining the Stark deceleration and velocity map imaging techniques. We show that for counterpropagating crossed beam geometries, the effect of the velocity spreads of the reagent beams on the angular resolution of the images is minimized. Futhermore, the counterpropagating geometry results in images that are symmetric with respect to the relative velocity vector. This allows for the use of inverse Abel transformation methods that enhance the resolution further. State-resolved diffraction oscillations in the differential cross sections are measured with an angular resolution approaching 0.3$^\\circ$. Distinct structures observed in the cross sections gauge the quality of recent \\emph{ab initio} potential energy surfaces for NO-rare gas atom collisions with unprecedented precision.

Vogels, Sjoerd N; von Zastrow, Alexander; Groenenboom, Gerrit C; van der Avoird, Ad; van de Meerakker, Sebastiaan Y T

2014-01-01T23:59:59.000Z

92

?-function-shaped Sb-doping profiles in Si(001) obtained using a low-energy accelerated-ion source during molecular-beam epitaxy  

Science Journals Connector (OSTI)

Two-dimensional (2D) buried ?-function-shaped Sb-doping profiles have been obtained in Si using a low-energy accelerated Sb-ion source during molecular-beam epitaxy. A combination of secondary-ion mass spectrometry (SIMS), capacitance-voltage (C-V) measurements, and cross-sectional transmission electron microscopy (XTEM) was used to investigate dopant distributions and to determine profile widths. The 2D-sheet Sb-doping concentration NSb, obtained by integrating SIMS ?-doping profiles in samples grown with substrate temperature Ts=620 C and Sb-ion acceleration potentials VSb=200 and 300 V, was found to vary linearly with the product of the Sb-ion flux and the exposure time (i.e., the ion dose) over the NSb range from 51012 to 21014 cm-2. The full width at half maximum (FWHM) concentration of ?-doping profiles in Si(001) films was less than the depth resolution of both SIMS and C-V measurements (?10 and 3 nm, respectively). High-resolution XTEM lattice images show that the FWHM was ?2 nm. This is consistent with dopant incorporation simulations, based upon a multisite transition-state dopant incorporation model, which show that accelerated-beam dopant species are trapped in near-surface substitutional sites with atomic mobilities between those of surface and bulk atoms. Dopant surface segregation during growth is strongly suppressed, and the dopant distribution is determined primarily by the straggle in ion trapping distributions. The present results are compared with profile broadening observed in ?-doped layers obtained by solid-phase epitaxy of amorphous Si containing a buried Sb layer.

W.-X. Ni; G. V. Hansson; J.-E. Sundgren; L. Hultman; L. R. Wallenberg; J.-Y. Yao; L. C. Markert; J. E. Greene

1992-09-15T23:59:59.000Z

93

Ga-assisted catalyst-free growth mechanism of GaAs nanowires by molecular beam epitaxy  

Science Journals Connector (OSTI)

The mechanisms of Ga-assisted GaAs nanowires grown by molecular beam epitaxy are addressed. The axial and radial growth rates as a function of the Ga rate and As pressure indicate that on the opposite of what is observed in thin film epitaxy, the growth rate of the nanowires is arsenic limited. As a consequence, the axial growth rate of the wires can be controlled by the As4 pressure. Additionally, due to the small As4 pressure leading to nanowire growth, the deposition on the facets is very slow, leading to a much lower radial growth rate. Finally, we present a model that is able to accurately describe the presented observations and predicts a maximum length of nontapered nanowires of 40?m.

C. Colombo; D. Spirkoska; M. Frimmer; G. Abstreiter; A. Fontcuberta i Morral

2008-04-28T23:59:59.000Z

94

Topological insulator Bi 2 Se 3 thin films grown on double-layer graphene by molecular beam epitaxy  

Science Journals Connector (OSTI)

Atomically flat thin films of topological insulator Bi 2 Se 3 have been grown on double-layer graphene formed on 6HSiC(0001) substrate by molecular beam epitaxy. By a combined study of reflection high energy electron diffraction and scanning tunneling microscopy we identified the Se-rich condition and temperature criterion for layer-by-layer growth of epitaxial Bi 2 Se 3 films. The as-grown films without doping exhibit a low defect density of 1.0 0.2 10 11 / cm 2 and become a bulk insulator at a thickness of ten quintuple layers as revealed by in situ angle resolved photoemission spectroscopy measurement.

Can-Li Song; Yi-Lin Wang; Ye-Ping Jiang; Yi Zhang; Cui-Zu Chang; Lili Wang; Ke He; Xi Chen; Jin-Feng Jia; Yayu Wang; Zhong Fang; Xi Dai; Xin-Cheng Xie; Xiao-Liang Qi; Shou-Cheng Zhang; Qi-Kun Xue; Xucun Ma

2010-01-01T23:59:59.000Z

95

Ultra-low resistance ohmic contacts to GaN with high Si doping concentrations grown by molecular beam epitaxy  

SciTech Connect (OSTI)

Ti/Al/Ni/Au ohmic contacts were formed on heavily doped n{sup +} metal-polar GaN samples with various Si doping concentrations grown by molecular beam epitaxy. The contact resistivity (R{sub C}) and sheet resistance (R{sub sh}) as a function of corresponding GaN free carrier concentration (n) were measured. Very low R{sub C} values (<0.09 {Omega} mm) were obtained, with a minimum R{sub C} of 0.035 {Omega} mm on a sample with a room temperature carrier concentration of {approx}5 Multiplication-Sign 10{sup 19} cm{sup -3}. Based on the systematic study, the role of R{sub C} and R{sub sh} is discussed in the context of regrown n{sup +} GaN ohmic contacts for GaN based high electron mobility transistors.

Afroz Faria, Faiza; Guo Jia; Zhao Pei; Li Guowang; Kumar Kandaswamy, Prem; Wistey, Mark; Xing Huili; Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)

2012-07-16T23:59:59.000Z

96

Ultra-high frequency photoconductivity decay in GaAs/Ge/GaAs double heterostructure grown by molecular beam epitaxy  

SciTech Connect (OSTI)

GaAs/Ge/GaAs double heterostructures (DHs) were grown in-situ using two separate molecular beam epitaxy chambers. High-resolution x-ray rocking curve demonstrates a high-quality GaAs/Ge/GaAs heterostructure by observing Pendelloesung oscillations. The kinetics of the carrier recombination in Ge/GaAs DHs were investigated using photoconductivity decay measurements by the incidence excitation from the front and back side of 15 nm GaAs/100 nm Ge/0.5 {mu}m GaAs/(100)GaAs substrate structure. High-minority carrier lifetimes of 1.06-1.17 {mu}s were measured when excited from the front or from the back of the Ge epitaxial layer, suggests equivalent interface quality of GaAs/Ge and Ge/GaAs. Wavelength-dependent minority carrier recombination properties are explained by the wavelength-dependent absorption coefficient of Ge.

Hudait, M. K.; Zhu, Y. [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States); Johnston, S. W. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)] [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Maurya, D.; Priya, S. [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Umbel, R. [Materials Science and Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Materials Science and Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)

2013-03-04T23:59:59.000Z

97

Investigation of the evolution of single domain ,,111...B CdTe films by molecular beam epitaxy on miscut ,,001...Si substrate  

E-Print Network [OSTI]

Investigation of the evolution of single domain ,,111...B CdTe films by molecular beam epitaxy; accepted for publication 22 July 1998 A comprehensive view of the microstructure of 111 B CdTe films grown and scanning transmission electron microscopy. It is found that in the initial growth stage, CdTe nucleates

Pennycook, Steve

98

Growth of GaN on SiC(0001) by Molecular Beam Epitaxy C. D. LEE (a), ASHUTOSH SAGAR (a), R. M. FEENSTRA  

E-Print Network [OSTI]

]. Silicon carbide has a much better lattice match to GaN (3.4%), and has gained in popularity in recent years as a substrate for both molecular beam epitaxy (MBE) and metal-organic vapor phase epitaxy of Ga where a transition between streaky and spotty behavior occurs in the reflection high energy electron

Feenstra, Randall

99

New electric quadrupole transitions of K2 observed in a pulsed molecular beam: The 1 1  

E-Print Network [OSTI]

-of-flight mass spectrometer. Since K has two naturally occurring iso- topes 39 K, 93.26%; 41 K, 6.73% , K2 has, which are allowed by electric quadrupole radiation. © 2000 American Institute of Physics. S0021-9606 00, be- cause the intensity for magnetic dipole radiation is about 10 5 times smaller

Kim, Bongsoo

100

Molecular line intensities as measures of cloud masses - II. Conversion factors for specific galaxy types  

E-Print Network [OSTI]

We present theoretically-established values of the CO-to-H2 and C-to-H2 conversion factors that may be used to estimate the gas masses of external galaxies. We consider four distinct galaxy types, represented by M51, NGC 6946, M82 and SMC N27. The physical parameters that best represent the conditions within the molecular clouds in each of the galaxy types are estimated using a chi^2 analysis of several observed atomic fine structure and CO rotational lines. This analysis is explored over a wide range of density, radiation field, extinction, and other relevant parameters. Using these estimated physical conditions in methods that we have previously established, CO-to-H2 conversion factors are then computed for CO transitions up to J=9-8. For the conventional CO(1-0) transition, the computed conversion factor varies significantly below and above the canonical value for the Milky Way in the four galaxy types considered. Since atomic carbon emission is now frequently used as a probe of external galaxies, we also present, for the first time, the C-to-H2 conversion factor for this emission in the four galaxy types considered.

T. A. Bell; S. Viti; D. A. Williams

2007-04-19T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" from the National Library of EnergyBeta (NLEBeta).
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101

Ion-beam-induced epitaxial vapor-phase growth: A molecular-dynamics study  

Science Journals Connector (OSTI)

Low-energy ions which bombard a vapor-deposited film of low adatom mobility during growth mobilize surface atoms in the vicinity of the ion impact, causing a modification in the evolving microstructure. In a two-dimensional molecular-dynamics simulation where inert-gas ions strike a growing film of Lennard-Jones particles, it is demonstrated that ion bombardment during growth causes the filling of voids quenched in during vapor condensation and induces homoepitaxial growth. The dependence of film density and degree of homoepitaxial growth on the ion-to-vapor arrival rate ratio and ion energy is studied in detail.

Karl-Heinz Mller

1987-05-15T23:59:59.000Z

102

Positioning effects on quantum dot solar cells grown by molecular beam epitaxy  

SciTech Connect (OSTI)

We report current-voltage and spectral response characteristics of high density InAs/GaAs quantum dot (QD) solar cells with different positions where dots are located. The short circuit current density (J{sub sc}), open circuit voltage (V{sub oc}), and external quantum efficiency of these cells under air mass 1.5 are presented and compared with a GaAs reference cell. An extended photoresponse in contrast to the GaAs reference cell was confirmed for all these cells. The effect of inserting QD layers into emitter and base region on device performance is shown. The J{sub sc} is reduced, while the V{sub oc} is maintained. The cell with QDs located toward the base side shows better performance, confirmed by both current-voltage and spectral response measurements.

Zhou, D.; Sharma, G.; Fimland, B. O. [Department of Electronics and Telecommunications, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Vullum, P. E.; Thomassen, S. F.; Holmestad, R.; Reenaas, T. W. [Department of Physics, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway)

2010-02-22T23:59:59.000Z

103

Momentum imaging spectrometer for molecular fragmentation dynamics induced by pulsed electron beam  

SciTech Connect (OSTI)

A momentum imaging spectrometer has been built for studying the electron impact molecular fragmentation dynamics. The setup consists of a pulsed electron gun and a time of flight system as well as a two-dimensional time and position sensitive multi-hit detector. The charged fragments with kinetic energy up to 10 eV can be detected in 4? solid angles and their three-dimensional momentum vectors can be reconstructed. The apparatus is tested by electron impact ionization of Ar and dissociative ionization of CO{sub 2}. By analyzing the ion-ion coincidence spectra, the complete and incomplete Coulomb fragmentation channels for CO{sub 2}{sup 2+} and CO{sub 2}{sup 3+} are identified. The kinetic energy release (KER) and angular correlation for the two-body breakup channel CO{sub 2}{sup 2+*}? O{sup +}+ CO{sup +} are reported. The peak value of total KER is found to be 6.8 eV which is consistent with the previous photoion-photoion coincidence studies, and the correlation angle of O{sup +} and CO{sup +} is also explicitly determined to be 172.5.

Wang, EnLiang; Shan, Xu; Shi, YuFeng; Tang, YaGuo; Chen, XiangJun [Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)] [Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2013-12-15T23:59:59.000Z

104

Structural and optical properties of InGaNGaN nanowire heterostructures grown by molecular beam epitaxy  

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

InGaN/GaN nanowire (NW) heterostructures grown by plasma assisted molecular beam epitaxy were studied in comparison to their GaN and InGaN counterparts. The InGaN/GaN heterostructure NWs are composed of a GaN NW, a thin InGaN shell, and a multifaceted InGaN cap wrapping the top part of the GaN NW. High-resolution transmission electron microscopy (HRTEM) images taken from different parts of a InGaN/GaN NW show a wurtzite structure of the GaN core and the epitaxial InGaN shell around it, while additional crystallographic domains are observed whithin the InGaN cap region. Large changes in the lattice parameter along the wire, from pure GaN to higher In concentration demonstrate the successful growth of a complex InGaN/GaN NW heterostructure. Photoluminescence (PL) spectra of these heterostructure NW ensembles show rather broad and intense emission peak at 2.1 eV. However, ?-PL spectra measured on single NWs reveal a reduced broadening of the visible luminescence. The analysis of the longitudinal optical phonon Raman peak position and its shape reveal a variation in the In content between 20% and 30%, in agreement with the values estimated by PL and HRTEM investigations. The reported studies are important for understanding of the growth and properties of NW heterostructures suitable for applications in optoelectronics and photovoltaics.

Limbach, F. [Institute of Bio- and Nanosystems (IBN-1), Research Centre Jlich GmbH and JARA-FIT Fundamentals of Future Information Technology (Germany); Gotschke, T. [Institute of Bio- and Nanosystems (IBN-1), Research Centre Jlich GmbH and JARA-FIT Fundamentals of Future Information Technology (Germany); Stoica, T. [Institute of Bio- and Nanosystems (IBN-1), Research Centre Jlich GmbH and JARA-FIT Fundamentals of Future Information Technology (Germany); Calarco, R. [Institute of Bio- and Nanosystems (IBN-1), Research Centre Jlich GmbH and JARA-FIT Fundamentals of Future Information Technology (Germany); Sutter, E. [Brookhaven National Lab., Upton, NY (United States); Ciston, J. [Brookhaven National Lab., Upton, NY (United States); Cusco, R. [Consell Superior d'Investigacions Cientifiques (CSIC), Barcelona (Spain); Artus, L. [Consell Superior d'Investigacions Cientifiques (CSIC), Barcelona (Spain); Kremling, S. [Univ. Wurzburg, Wilhelm Conrad Rontgen Research Centre Complex Matter Systems, Wurzburg (Germany); Hofling, S. [Univ. Wurzburg, Wilhelm Conrad Rontgen Research Centre Complex Matter Systems, Wurzburg (Germany); Worschech, L. [Univ. Wurzburg, Wilhelm Conrad Rontgen Research Centre Complex Matter Systems, Wurzburg (Germany); Grutzmacher, D. [Institute of Bio- and Nanosystems (IBN-1), Research Centre Jlich GmbH and JARA-FIT Fundamentals of Future Information Technology (Germany)

2011-01-07T23:59:59.000Z

105

Stoichiometric, nonstoichiometric, and locally nonstoichiometric SrTiO{sub 3} films grown by molecular beam epitaxy  

SciTech Connect (OSTI)

SrTiO{sub 3} films were grown by reactive molecular beam epitaxy to have varying degrees of both global and local cationic nonstoichiometries (with stoichiometry defined as a 1:1 ratio of Sr:Ti). Slight global excesses of Sr and Ti resulted in two-fold reconstructions in the reflection high-energy electron diffraction patterns along the [110] and [100] azimuths, respectively. Larger global nonstoichiometries (2:1 and 1:2 ratios) were also accommodated into the film's crystalline structure and affected the long-range crystalline order as observed in the x-ray diffraction patterns, both of which were related to the parent perovskite pattern. Local nonstoichiometries were introduced by depositing multiple monolayers (MLs) (from 2 to 33) of SrO and TiO{sub 2} in an alternating fashion, while maintaining the global SrTiO{sub 3} stoichiometry. These layered structures of SrO and TiO{sub 2} blocks inter-reacted during growth to form highly crystalline epitaxial SrTiO{sub 3}. Films grown in this manner with blocks thicker than 8 MLs were fully relaxed and, when the block thicknesses ranged between 8 and 10 MLs, the full widths at half maxima of 2{theta} peaks were narrower than the standard SrTiO{sub 3} films having blocks 1 ML thick.

Fisher, P.; Du, H.; Skowronski, M.; Salvador, P. A. [Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Maksimov, O. [Electro-Optics Center, Pennsylvania State University, Freeport, Pennsylvania 16229 (United States); Weng, X. [Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

2008-01-01T23:59:59.000Z

106

Direct imaging of InSb (110)-(1x1) surface grown by molecular beam epitaxy  

SciTech Connect (OSTI)

High-resolution transmission electron microscopy under a profile imaging condition (HR-profile TEM) was employed to determine the structural model for the InSb(110)-(1x1) relaxation surface grown by molecular beam epitaxy (MBE). HR-profile TEM analyses indicate that the chevron model, which is widely accepted for zinc-blende-type III-V(110)-(1x1) surfaces prepared by cleavage, is also applicable to the InSb(110)-(1x1) surface prepared under an Sb-rich MBE condition. The assignment of atomic species (In or Sb) of InSb(110)-(1x1) surfaces was confirmed based on a HR-profile TEM image that captures the connected facets of InSb(110)-(1x1) and InSb(111)B-(2x2). On the basis of the well-known atomic species of InSb(111)B-(2x2), the atomic species of the InSb(110)-(1x1) surface were deduced straightforwardly: the atoms shifted upward and downward at the topmost layer of the InSb(110)-(1x1) surface are Sb and In, respectively. The atomic arrangements of the InSb(110)-(1x1)-InSb(111)B-(2x2) facet determined by HR-profile TEM may represent the atomic arrangements of zinc-blende-type III-V(331)B surfaces.

Mishima, T. D. [Homer L. Dodge Department of Physics and Astronomy, and Center for Semiconductor Physics in Nanostructures, University of Oklahoma, Norman, Oklahoma 73019 (United States)

2011-10-01T23:59:59.000Z

107

Electroreflectance study of effects of indium segregation in molecular-beam-epitaxy-grown InGaAs/GaAs  

Science Journals Connector (OSTI)

Electrolyte electroreflectance (EER) experiments were performed on In 0.22 Ga 0.78 As/GaAs single quantum wells grown by the conventional molecular-beam-epitaxy (MBE) shutter operation and also by modified MBE shutter operation intended to form more compositionally abrupt normal and inverted interfaces. The latter included controlled thermal desorption of the surface segregated In at the InGaAs layer surface (flash off) and the deposition of In at the InGaAs/GaAs interface to eliminate compositional broadening (predeposition). The fundamental energy gap and subband transitions were determined experimentally and compared with an accurate calculation of the potential well problem including strain. These results confirmed the segregation of In atoms near the interface. The segregation was maximum in the conventional (normal) MBE sample and least with the modified growth incorporating predeposition and flash off as expected. The segregated atoms are observed to act as dopants and form junctions near the InGaAs/GaAs interface. This study shows that EER can be used as an effective tool for studying the segregation process in MBE growth.

K. Chattopadhyay; J. Aubel; S. Sundaram; J. E. Ehret; R. Kaspi; Keith R. Evans

1997-01-01T23:59:59.000Z

108

Hall and electroreflectance studies of the effects of doping in mercurycadmium telluride grown by molecular?beam epitaxy  

Science Journals Connector (OSTI)

Hall and electrolyte electroreflectance (EER) measurements have been performed on a series of mercurycadmium telluride samples grown by molecular?beam heteroepitaxy on semi?insulating GaAs substrates and varying from p type to heavily dopedn type. Our results show for as?grown n?type samples grown under nearly ideal conditions that the mobilities are high and that the n character is not primarily associated with defects. Our Hall results show that as one departs from nearly ideal growth conditions in order to obtain higher n?type doping levels the mobility decreases precipitously. An analysis of the temperature dependence of the mobility suggests that this decrease is associated with a rapid increase in both the number of ionized impurities and the number of neutral scattering centers. Our EER results show that the initial decrease of the mobility is associated with the formation of inhomogeneous strains and to a lesser extent both point defects and two?dimensional structural faults. They also show that the final precipitous decline in the high?temperature mobility is associated with a decrease in the density of inhomogeneous strains accompanied by the formation of many more two?dimensional structural faults although they are not sensitive to the high degree of compensation which is largely responsible for the precipitous decline in the low?temperature mobility.

Paul M. Raccah; J. W. Garland; Z. Zhang; Amy H. M. Chu; J. Reno; I. K. Sou; M. Boukerche; J. P. Faurie

1986-01-01T23:59:59.000Z

109

Oxygen vacancy induced photoluminescence and ferromagnetism in SrTiO{sub 3} thin films by molecular beam epitaxy  

SciTech Connect (OSTI)

SrTiO{sub 3} thin films were epitaxially grown on (100) SrTiO{sub 3} substrates using molecular beam epitaxy. The temperature for growth of the films was optimized, which was indicated by x-ray diffraction and further confirmed by microstructural characterization. Photoluminescence spectra show that oxygen-vacancy contributes to red and blue luminescence of oxygen-deficient post-annealed films, and a red shift was observed in blue region. On the other hand, ferromagnetism in film form SrTiO{sub 3} was observed from 5 K to 400 K and could be further enhanced with decreasing oxygen plasma partial pressure in annealing processes, which might be explained by the theory involving d{sup 0} magnetism related to oxygen-vacancy. From the cooperative investigations of optical and magnetic properties, we conclude that intrinsic defects, especially oxygen-vacancy, can induce and enhance luminescence and magnetism in SrTiO{sub 3} films.

Xu, Wenfei; Yang, Jing; Bai, Wei; Tang, Kai; Zhang, Yuanyuan [Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, 500 Dongchuan Rd., Shanghai 200241 (China)] [Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, 500 Dongchuan Rd., Shanghai 200241 (China); Tang, Xiaodong [Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, 500 Dongchuan Rd., Shanghai 200241 (China) [Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, 500 Dongchuan Rd., Shanghai 200241 (China); Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Rd., Shanghai 200050 (China)

2013-10-21T23:59:59.000Z

110

Electrical properties of scandium nitride epitaxial films grown on (100) magnesium oxide substrates by molecular beam epitaxy  

SciTech Connect (OSTI)

Scandium nitride (ScN) films were grown on (100) MgO single crystals by a molecular beam epitaxy method. The effects of growth conditions, including [Sc]/[N] ratio, growth temperature, and nitrogen radical state, on the electrical properties of the ScN films were studied. The ScN films comprised many small columnar grains. Hall coefficient measurements confirmed that the ScN films were highly degenerate n-type semiconductors and that the carrier concentration of the ScN films was sensitive to the growth temperature and the nitrogen radical states during the film growth. The carrier concentrations of the ScN films ranged from 10{sup 19}10{sup 21} cm{sup ?3} while the Hall mobilities ranged from 50130 cm{sup 2}V{sup ?1}s{sup ?1} for undoped films. The temperature-dependent Hall coefficient measurements showed that the carrier concentration is nearly independent of temperature, indicating that the change in resistivity with temperature is explained by a change in the Hall mobility. The temperature-dependence of the Hall mobility was strongly affected by the growth conditions.

Ohgaki, Takeshi; Watanabe, Ken; Adachi, Yutaka; Sakaguchi, Isao; Hishita, Shunichi; Ohashi, Naoki; Haneda, Hajime [Environment and Energy Materials Research Division, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)] [Environment and Energy Materials Research Division, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

2013-09-07T23:59:59.000Z

111

Oxygen plasma power dependence on ZnO grown on porous silicon substrates by plasma-assisted molecular beam epitaxy  

SciTech Connect (OSTI)

ZnO thin films were deposited on porous silicon by plasma-assisted molecular beam epitaxy using different radio frequency power settings. Optical emission spectrometry was applied to study the characteristics of the oxygen plasma, and the effects of the radio frequency power on the properties of the ZnO thin films were evaluated by X-ray diffraction, scanning electron microscopy, and photoluminescence. The grain sizes for radio frequency powers of 100, 200, and 300 W were 46, 48, and 62 nm, respectively. In addition, the photoluminescence intensities of the ultraviolet and the visible range increased at 300 W, because the density of the atomic oxygen transitions increased. The quality of the ZnO thin films was enhanced, but the deep-level emission peaks increased with increasing radio frequency power. The structural and optical properties of the ZnO thin films were improved at the radio frequency power of 300 W. Moreover, the optical properties of the ZnO thin films were improved with porous silicon, instead of Si.

Nam, Giwoong [Department of Nano Engineering, Inje University, Gimhae, Gyungnam 621-749 (Korea, Republic of)] [Department of Nano Engineering, Inje University, Gimhae, Gyungnam 621-749 (Korea, Republic of); Kim, Min Su [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Gimhae, Gyungnam 621-749 (Korea, Republic of)] [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Gimhae, Gyungnam 621-749 (Korea, Republic of); Kim, Do Yeob [Holcombe Department of Electrical and Computer Engineering, Center for Optical Materials Science and Engineering Technologies, Clemson University, Clemson, SC 29634 (United States)] [Holcombe Department of Electrical and Computer Engineering, Center for Optical Materials Science and Engineering Technologies, Clemson University, Clemson, SC 29634 (United States); Yim, Kwang Gug [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Gimhae, Gyungnam 621-749 (Korea, Republic of)] [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Gimhae, Gyungnam 621-749 (Korea, Republic of); Kim, Soaram [Department of Nano Engineering, Inje University, Gimhae, Gyungnam 621-749 (Korea, Republic of)] [Department of Nano Engineering, Inje University, Gimhae, Gyungnam 621-749 (Korea, Republic of); Kim, Sung-O. [Holcombe Department of Electrical and Computer Engineering, Center for Optical Materials Science and Engineering Technologies, Clemson University, Clemson, SC 29634 (United States)] [Holcombe Department of Electrical and Computer Engineering, Center for Optical Materials Science and Engineering Technologies, Clemson University, Clemson, SC 29634 (United States); Lee, Dong-Yul [Epi R and D Team, Samsung LED Co. Ltd., Suwon, Gyeonggi-do 443-373 (Korea, Republic of)] [Epi R and D Team, Samsung LED Co. Ltd., Suwon, Gyeonggi-do 443-373 (Korea, Republic of); Leem, Jae-Young, E-mail: jyleem@inje.ac.kr [Department of Nano Engineering, Inje University, Gimhae, Gyungnam 621-749 (Korea, Republic of) [Department of Nano Engineering, Inje University, Gimhae, Gyungnam 621-749 (Korea, Republic of); Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Gimhae, Gyungnam 621-749 (Korea, Republic of)

2012-10-15T23:59:59.000Z

112

Control of tensile strain and interdiffusion in Ge/Si(001) epilayers grown by molecular-beam epitaxy  

SciTech Connect (OSTI)

Tensile-strained and n-doped Ge has emerged as a potential candidate for the realization of optoelectronic devices that are compatible with the mainstream silicon technology. Tensile-strained Ge/Si epilayers can be obtained by using the difference of thermal expansion coefficients between Ge and Si. We have combined various surface, structural, and compositional characterizations to investigate the growth mode and the strain state in Ge/Si epilayers grown by molecular-beam epitaxy. The Ge growth was carried out using a two-step approach: a low-temperature growth to produce relaxed and smooth buffer layers, which is followed by a high-temperature growth to get high quality Ge layers. The existence of a substrate temperature window from 260 to 300 C is evidenced, which allows to completely suppress the Ge/Si Stranski-Krastanov growth. As a consequence of the high temperature growth, a tensile strain lying in the range of 0.22%0.24% is obtained. Concerning the effect of thermal annealing, it is shown that cyclic annealing may allow increasing the tensile strain up to 0.30%. Finally, we propose an approach to use carbon adsorption to suppress Si/Ge interdiffusion, which represents one of the main obstacles to overcome in order to realize pure Ge-based optoelectronic devices.

Luong, T. K. P.; Dau, M. T.; Zrir, M. A.; Le Thanh, V.; Petit, M. [Aix-Marseille Universit, CNRS CINaM-UMR 7325, F-13288 Marseille Cedex 09 (France)] [Aix-Marseille Universit, CNRS CINaM-UMR 7325, F-13288 Marseille Cedex 09 (France); Stoffel, M.; Rinnert, H. [Universit de Lorraine, Institut Jean Lamour, CNRS UMR 7198, Nancy-Universit, BP 70239, 54506 Vandoeuvre-ls-Nancy Cedex (France)] [Universit de Lorraine, Institut Jean Lamour, CNRS UMR 7198, Nancy-Universit, BP 70239, 54506 Vandoeuvre-ls-Nancy Cedex (France); Ghrib, A.; El Kurdi, M.; Boucaud, P. [Institut d'Electronique Fondamentale, CNRS UMR 8622, Universit Paris-Sud, Ba-carett. 220, 91405 Orsay (France)] [Institut d'Electronique Fondamentale, CNRS UMR 8622, Universit Paris-Sud, Ba-carett. 220, 91405 Orsay (France); Murota, J. [Research Institute of Electrical Communications, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)] [Research Institute of Electrical Communications, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

2013-08-28T23:59:59.000Z

113

High-efficiency cross-beam magnetic electron-impact source for improved miniature Mattauch-Herzog mass spectrometer performance  

SciTech Connect (OSTI)

We describe a newly designed cross-beam magnetic electron-impact ion source (CBM-EI). We demonstrate its superiority in comparison with a conventional source (CB-EI) when used with a commercial miniature sector-field-type, non-scanning mass spectrometer featuring Mattauch-Herzog geometry (MH-MS) and a permanent sector-field magnet. This paper clearly shows the value of the CBM-EI for enhancing MH-MS sensitivity. Unlike secondary electron-multiplier type detectors, the pixelated detector (IonCCD Trade-Mark-Sign ) used in the commercial MH-MS has no gain. The MH-MS/IonCCD system is therefore challenged to compete with time-of-flight and quadrupole MS systems due to their higher ion transmissions and detector gains. Using the new CBM-EI, we demonstrate an instrument sensitivity increase of 20-fold to 100-fold relative to the CB-EI-equipped instrument. This remarkable signal increase by the simple addition of the magnet assembly arises from the magnet-induced gyromotion of the thermionic electrons, which vastly increases the effective path length of the electrons through the ionization region, and the collimated nature of the electron flux, which optimizes the ion transmission through the 100-{mu}m object slit of the MH-MS. Some or all of the realized sensitivity increase may be exchanged for an increase in resolution and/or mass range through the use of a narrower object slit, or for a reduction in ion-source pressure to limit quenching. The CBM-EI should facilitate development of a differentially pumped ion source to extend the lifetime of the filament, especially in otherwise intractable applications associated with oxidizing and corrosive samples.

Hadjar, O.; Fowler, W. K. [OI Analytical/CMS Field Products, 2148 Pelham Parkway, Bldg. 400, Pelham, Alabama 35124 (United States)

2012-06-15T23:59:59.000Z

114

Measurement of the Zero-Field Hyperfine Structure of a Single Vibration-Rotation Level of Na2 by a Laser-Fluorescence Molecular-Beam-Resonance Technique  

Science Journals Connector (OSTI)

By replacing the A and B magnets of the conventional molecular-beam-resonance technique with laser optical-pumping regions, we have developed a method for the observation of hfs in a single molecular-vibration-rotation level of arbitrary J. We obtain for the electric quadrupole and spin-rotation constants of the X?g1+, v??=0, J??=28 level of Na2: eqQ=-463.70.9 kHz; |c|=0.170.03 kHz. We also report the first observation of a spin-rotation transition.

S. D. Rosner; R. A. Holt; T. D. Gaily

1975-09-22T23:59:59.000Z

115

Three-dimensional molecular imaging by infrared laser ablation electrospray ionization mass spectrometry  

DOE Patents [OSTI]

The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

Vertes, Akos; Nemes, Peter

2013-07-16T23:59:59.000Z

116

Three-dimensional molecular imaging by infrared laser ablation electrospray ionization mass spectrometry  

DOE Patents [OSTI]

The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

Vertes, Akos; Nemes, Peter

2012-10-30T23:59:59.000Z

117

Characterization of high quality InN grown on production-style plasma assisted molecular beam epitaxy system  

SciTech Connect (OSTI)

In this work, the authors report step-flow growth mode of InN on [0001] oriented GaN templates, using a production-style molecular beam epitaxy system, Veeco GEN200 registered , equipped with a plasma source. Using adaptive growth conditions, they have obtained a surface morphology that exhibits the step-flow features. The root mean squared roughness over an area of 5x5 {mu}m{sup 2} is 1.4 nm with monolayer height terrace steps (0.281 nm), based on atomic force microscopy. It has been found that the presence of In droplets leads to defective surface morphology. From x-ray diffraction, they estimate edge and screw dislocation densities. The former is dominant over the latter. Micro-Raman spectra reveal narrow E{sub 2}{sup 2} phonon lines consistent with excellent crystalline quality of the epitaxial layers. The Hall mobility of 1 {mu}m thick InN layers, grown in step-flow mode, is slightly higher than 1400 cm{sup 2}/V s, while for other growth conditions yielding a smooth surface with no well-defined steps, mobility as high as 1904 cm{sup 2}/V s at room temperature has been measured. The samples exhibit high intensity photoluminescence (PL) with a corresponding band edge that shifts with free carrier concentration. For the lowest carrier concentration of 5.6x10{sup 17} cm{sup -3}, they observe PL emission at {approx}0.64 eV.

Gherasoiu, I.; O'Steen, M.; Bird, T.; Gotthold, D.; Chandolu, A.; Song, D. Y.; Xu, S. X.; Holtz, M.; Nikishin, S. A.; Schaff, W. J. [Veeco Instruments Inc., MBE Operations, 4900 Constellation Drive, St. Paul, Minnesota 55127 (United States); Nano Tech Center, Texas Tech University, Lubbock, Texas 79409 (United States); Department of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14583 (United States)

2008-05-15T23:59:59.000Z

118

Localized Si enrichment in coherent self-assembled Ge islands grown by molecular beam epitaxy on (001)Si single crystal  

SciTech Connect (OSTI)

Transmission electron microscopy (TEM), atomic force microscopy, and Rutherford backscattering spectrometry (RBS) have been used to investigate the morphology, structure, and composition of self-assembled Ge islands grown on Si (001) substrates by molecular beam epitaxy (MBE) at different temperatures. Increasing the temperature from 550 Degree-Sign C to 700 Degree-Sign C causes progressive size and shape uniformity, accompanied by enhanced Si-Ge intermixing within the islands and their wetting layer. Elemental maps obtained by energy filtered-TEM (EF-TEM) clearly show pronounced Si concentration not only in correspondence of island base perimeters, but also along their curved surface boundaries. This phenomenon is strengthened by an increase of the growth temperature, being practically negligible at 550 Degree-Sign C, while very remarkable already at 650 Degree-Sign C. The resulting island shape is affected, since this localized Si enrichment not only provides strain relief near their highly stressed base perimeters but it also influences the cluster surface energy by effective alloying, so as to form Si-enriched SiGe interfaces. Further increase to 700 Degree-Sign C causes a shape transition where more homogenous Si-Ge concentration profiles are observed. The crucial role played by local 'flattened' alloyed clusters, similar to truncated pyramids with larger bases and enhanced Si enrichment at coherently stressed interfaces, has been further clarified by EF-TEM analysis of a multi-layered Ge/Si structure containing stacked Ge islands grown at 650 Degree-Sign C. Sharp accumulation of Si has been here observed not only in proximity of the uncapped island surface in the topmost layer but also at the buried Ge/Si interfaces and even in the core of such capped Ge islands.

Valvo, M. [Dipartimento di Fisica e Astronomia, Universita di Catania, Via S. Sofia 64, I-95127 Catania (Italy); Bongiorno, C.; Giannazzo, F. [IMM-CNR, VIII strada 5, 95121 Catania (Italy); Terrasi, A. [Dipartimento di Fisica e Astronomia, Universita di Catania, Via S. Sofia 64, I-95127 Catania (Italy); MATIS IMM-CNR UOS Catania (Universita), via S. Sofia 64, 95123 Catania (Italy)

2013-01-21T23:59:59.000Z

119

Molecular Science Computing | EMSL  

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

Scientific Capabilities Molecular Science Computing Overview Cell Isolation and Systems Analysis Deposition and Microfabrication Mass Spectrometry Microscopy Molecular Science...

120

Molecular Beam Epitaxy | EMSL  

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

temperature monitored by a two-color pyrometer andor thermocouple In situ optical (atomic absorption) and reflection high-energy electron diffraction (RHEED) probes for...

Note: This page contains sample records for the topic "molecular beam mass" 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

Time-Resolved Molecular Characterization of Limonene/Ozone Aerosol using High-Resolution Electrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

Molecular composition of limonene/O3 secondary organic aerosol (SOA) was investigated using high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) as a function of reaction time. SOA was generated by ozonation of D-limonene in a reaction chamber and sampled at different time intervals using a cascade impactor. The SOA samples were extracted into acetonitrile and analyzed using a HR-ESI-MS instrument with a resolving power of 100,000 (m/?m). The resulting mass spectra provided detailed information about the extent of oxidation inferred from the O:C ratios, double bond equivalency (DBE) factors, and aromaticity indexes (AI) in hundreds of identified individual SOA species.

Bateman, Adam P.; Nizkorodov, Serguei; Laskin, Julia; Laskin, Alexander

2009-09-09T23:59:59.000Z

122

Born-Oppenheimer and hyperspherical adiabatic approximations in the nuclear- and molecular-mass limits  

Science Journals Connector (OSTI)

Ground-state energies of a three-particle system composed of a distinct and two equal-mass particles interacting via localS-wave potentials is studied using Born-Oppenheimer and hyperspherical adiabatic approxima...

Sadhan K. Adhikari; V. P. Brito; H. T. Coelho; T. K. Das

1992-01-01T23:59:59.000Z

123

Versatile piezoelectric pulsed molecular beam source for gaseous compounds and organic molecules with femtomole accuracy for UHV and surface science applications  

SciTech Connect (OSTI)

This note describes the construction of a piezoelectric pulsed molecular beam source based upon a design presented in an earlier work [D. Proch and T. Trickl, Rev. Sci. Instrum. 60, 713 (1988)]. The design features significant modifications that permit the determination of the number of molecules in a beam pulse with an accuracy of 1x10{sup 11} molecules per pulse. The 21 cm long plunger-nozzle setup allows the molecules to be brought to any point of the UHV chamber with very high intensity. Furthermore, besides typical gaseous compounds, also smaller organic molecules with a vapor pressure higher than 0.1 mbar at room temperature may serve as feed material. This makes the new design suitable for various applications in chemical and surface science studies.

Schiesser, Alexander; Schaefer, Rolf [Eduard-Zintl-Institut fuer Anorganische und Physikalische Chemie, Technische Universitaet Darmstadt, Petersenstrasse 20, 64287 Darmstadt (Germany)

2009-08-15T23:59:59.000Z

124

Erbium-doped transparent glass ceramic optical Characterization using mass spectroscopy and molecular dynamics modeling.  

E-Print Network [OSTI]

Erbium-doped transparent glass ceramic optical fibres: Characterization using mass spectroscopy) doped silica-based optical fibres with transparent glass ceramic (TGC) core were fabricated through properties of the erbium ions embedded within the phospho-silicate DNP. These results permit to get more

Boyer, Edmond

125

Strong room-temperature ferromagnetism of high-quality lightly Mn-doped ZnO grown by molecular beam epitaxy  

SciTech Connect (OSTI)

Strong room-temperature ferromagnetism is demonstrated in single crystalline Mn-doped ZnO grown by molecular beam epitaxy. With a low Mn concentration of 2 Multiplication-Sign 10{sup 19} cm{sup -3}, Mn-doped ZnO films exhibited room-temperature ferromagnetism with a coercivity field larger than 200 Oe, a large saturation moment of 6 {mu}{sub B}/ion, and a large residue moment that is {approx}70% of the saturation magnetization. Isolated ions with long range carrier mediated spin-spin coupling may be responsible for the intrinsic ferromagnetism.

Zuo Zheng; Zhou Huimei; Olmedo, Mario J.; Kong Jieying; Liu Jianlin [Quantum Structures Laboratory, Department of Electrical Engineering, University of California - Riverside, Riverside, California 92521 (United States); Beyermann, Ward P. [Department of Physics and Astronomy, University of California - Riverside, Riverside, California 92521 (United States); Zheng Jianguo [Laboratory for Electron and X-ray Instrumentation, California Institute for Telecommunications and Information Technology, University of California - Irvine, Irvine, California 92697 (United States); Xin Yan [NHMFL, Florida State University, 1800 E. Paul Dirac Dr., Tallahassee, Florida 32310-3706 (United States)

2012-09-01T23:59:59.000Z

126

Magneto-transport properties of InAs nanowires laterally-grown by selective area molecular beam epitaxy on GaAs (110) masked substrates  

SciTech Connect (OSTI)

We prepared InAs nanowires (NWs) by lateral growth on GaAs (110) masked substrates in molecular beam epitaxy. We measured magneto-transport properties of the InAs NWs. In spite of parallel-NW multi-channels, we observed fluctuating magneto-conductance. From the fluctuation, we evaluated phase coherence length as a function of measurement temperature, and found decrease in the length with increase in the temperature. We also evaluate phase coherence length as a function of gate voltage.

Akabori, M.; Yamada, S. [Center for Nano-Materials and Technology, Japan Advanced Institute of Science and Technology, 1-1, Asahidai, Nomi, Ishikawa 923-1292 (Japan)

2013-12-04T23:59:59.000Z

127

Preliminary design report of a relativistic-Klystron two-beam-accelerator based power source for a 1 TeV center-of-mass next linear collider  

SciTech Connect (OSTI)

A preliminary point design for an 11.4 GHz power source for a 1 TeV center-of-mass Next Linear Collider (NLC) based on the Relativistic-Klystron Two-Beam-Accelerator (RK-TBA) concept is presented. The present report is the result of a joint LBL-LLNL systems study. consisting of three major thrust areas: physics, engineering, and costing. The new RK-TBA point design, together with our findings in each of these areas, are reported.

Yu, S.; Goffeney, N.; Henestroza, E. [Lawrence Berkeley Lab., CA (United States)] [and others

1995-02-22T23:59:59.000Z

128

Study of structural properties of cubic InN films on GaAs(001) substrates by molecular beam epitaxy and migration enhanced epitaxy  

SciTech Connect (OSTI)

InN epitaxial films with cubic phase were grown by rf-plasma-assisted molecular beam epitaxy (RF-MBE) on GaAs(001) substrates employing two methods: migration-enhanced epitaxy (MEE) and conventional MBE technique. The films were synthesized at different growth temperatures ranging from 490 to 550 Degree-Sign C, and different In beam fluxes (BEP{sub In}) ranging from 5.9 Multiplication-Sign 10{sup -7} to 9.7 Multiplication-Sign 10{sup -7} Torr. We found the optimum conditions for the nucleation of the cubic phase of the InN using a buffer composed of several thin layers, according to reflection high-energy electron diffraction (RHEED) patterns. Crystallographic analysis by high resolution X-ray diffraction (HR-XRD) and RHEED confirmed the growth of c-InN by the two methods. We achieved with the MEE method a higher crystal quality and higher cubic phase purity. The ratio of cubic to hexagonal components in InN films was estimated from the ratio of the integrated X-ray diffraction intensities of the cubic (002) and hexagonal (1011) planes measured by X-ray reciprocal space mapping (RSM). For MEE samples, the cubic phase of InN increases employing higher In beam fluxes and higher growth temperatures. We have obtained a cubic purity phase of 96.4% for a film grown at 510 Degree-Sign C by MEE.

Casallas-Moreno, Y. L.; Perez-Caro, M.; Gallardo-Hernandez, S.; Ramirez-Lopez, M.; Martinez-Velis, I.; Lopez-Lopez, M. [Physics Department, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 Mexico D.F. (Mexico)] [Physics Department, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 Mexico D.F. (Mexico); Escobosa-Echavarria, A. [Electric Engineering Department, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 Mexico D.F. (Mexico)] [Electric Engineering Department, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 Mexico D.F. (Mexico)

2013-06-07T23:59:59.000Z

129

Molecular Gas in Early-type Galaxies  

E-Print Network [OSTI]

toward the center (first seen in the molecular gas in A+3.4 Molecular Gas Mass . . . . . . .of the molecular gas . . . . . . . . . . 2.4.3 Mass of

Alatalo, Katherine Anne

2012-01-01T23:59:59.000Z

130

Structural characterization of SiGe/Si single wells grown by disilane and solid-Ge molecular beam epitaxy with varied disilane cracking temperature  

Science Journals Connector (OSTI)

Structural properties of SiGe/Si single wells are studied by double-crystal X-ray diffraction. Four SiGe/Si single wells have been grown on Si (001) at 750C by disilane and solid-Ge molecular beam epitaxy with varied disilane cracking temperature. Using dynamic theory, together with kinematic theory and the specific growth procedure adopted, structural parameters in the multilayer structure are determined precisely. The results are compared with those obtained from PL and XTEM as well as AES measurements. It is found that disilane adsorption is dependent on cracking temperature as well as Ge incorporation. Disilane adsorption is increased by cracking disilane while it decreased with Ge incorporation

J.P. Liu; M.Y. Kong; D.D. Huang; J.P. Li; D.Z. Sun

1998-01-01T23:59:59.000Z

131

Role of adsorption kinetics in the low-temperature Si growth by gas-source molecular beam epitaxy: In situ observations and detailed modeling of the growth  

SciTech Connect (OSTI)

The growth rate and surface hydrogen coverage during Si gas-source molecular beam epitaxy using disilane have been obtained as functions of both the growth temperature and the source-gas pressure. The activation energy of the low-temperature (<600{sup o}C) growth rate was found to increase with the source-gas pressure, indicating a contribution by the adsorption process in these low-temperature growth kinetics. Several growth models have been constructed based on the results, among which the two-site/four-site-adsorption model [M. Suemitsu Jpn. J. Appl. Phys., Part 236, L625 (1997)] showed the best fit to both the growth rate and the hydrogen coverage. {copyright} 2001 American Institute of Physics.

Murata, Takeshi; Nakazawa, Hideki; Tsukidate, Yoshikazu; Suemitsu, Maki

2001-08-06T23:59:59.000Z

132

Electroluminescence at 1.54 {mu}m in Si:Er/Si structures grown by sublimation molecular-beam epitaxy  

SciTech Connect (OSTI)

In Si:Er/Si diode structures grown by sublimation molecular-beam epitaxy in a vacuum with a pressure of {approx}10{sup -7} mbar at temperatures 520-580 deg. C, the intensity of room-temperature electroluminescence at 1.54 {mu}m is studied as a function of the concentration and distribution of erbium and donor impurities in the space-charge region (SCR) and the SCR width. Methods for obtaining electroluminescence in diodes with a wide (0.1-1 {mu}m) SCR are developed. The mean free path of electrons with respect to their interaction with Er centers and the threshold energy a free electron needs in order to excite an Er-shell electron are determined. The values of electric-field strength corresponding to breakdown in silicon p-i-n diodes with and without Er doping are obtained experimentally. A model describing the interaction of hot electrons with Er centers is suggested.

Kuznetsov, V. P. [Nizhni Novgorod State University, Physicotechnical Research Institute (Russian Federation)], E-mail: Kuznetsov_VP@mail.ru; Remizov, D. Yu. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Shabanov, V. N.; Rubtsova, R. A. [Nizhni Novgorod State University, Physicotechnical Research Institute (Russian Federation); Stepikhova, M. V.; Kryzhov, D. I. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Shushunov, A. N.; Belova, O. V. [Nizhni Novgorod State University, Physicotechnical Research Institute (Russian Federation); Krasil'nik, Z. F. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Maksimov, G. A. [Nizhni Novgorod State University, Physicotechnical Research Institute (Russian Federation)

2006-07-15T23:59:59.000Z

133

Formation behavior of Be{sub x}Zn{sub 1-x}O alloys grown by plasma-assisted molecular beam epitaxy  

SciTech Connect (OSTI)

We report the phase formation behavior of Be{sub x}Zn{sub 1-x}O alloys grown by plasma-assisted molecular beam epitaxy. We find the alloy with low- and high-Be contents could be obtained by alloying BeO into ZnO films. X-ray diffraction measurements shows the c lattice constant value shrinks, and room temperature absorption shows the energy band-gap widens after Be incorporated. However, the alloy with intermediate Be composition are unstable and segregated into low- and high-Be contents BeZnO alloys. We demonstrate the phase segregation of Be{sub x}Zn{sub 1-x}O alloys with intermediate Be composition resulted from large internal strain induced by large lattice mismatch between BeO and ZnO.

Chen, Mingming; Zhu, Yuan; Su, Longxing; Zhang, Quanlin; Chen, Anqi; Ji, Xu; Xiang, Rong; Gui, Xuchun; Wu, Tianzhun [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)] [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Pan, Bicai [Department of Physics and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China)] [Department of Physics and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Tang, Zikang [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China) [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China)

2013-05-20T23:59:59.000Z

134

A series of layered intergrowth phases grown by molecular beam epitaxy: Sr{sub m}TiO{sub 2+m}(m=1-5)  

SciTech Connect (OSTI)

Sr{sub m}TiO{sub 2+m} phases having one TiO{sub 2} layer sandwiched between m SrO layers were grown using molecular beam epitaxy. The out-of-plane (in-plane) lattice parameters determined by x-ray diffraction were c(a)=9.14 A (3.78 A), 23.55 A (3.75 A), and 14.60 A (3.75 A) for Sr{sub 3}TiO{sub 5}, Sr{sub 4}TiO{sub 6}, and Sr{sub 5}TiO{sub 7}, respectively. Both lattice parameters change abruptly on going from the m=2 Ruddlesden-Popper phase to m=3 phase, indicating a significant change in the bond lengths (or strain states) on transitioning from the known members to the higher order members of this structural family. Electron microscopy confirmed the artificially layered structures.

Fisher, P.; Wang, S.; Skowronski, M.; Salvador, P. A.; Snyder, M.; Maksimov, O. [Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Electro-Optics Center, Pennsylvania State University, Freeport, Pennsylvania 16229 (United States)

2007-12-17T23:59:59.000Z

135

Structural properties of SrO thin films grown by molecular beam epitaxy on LaAlO{sub 3} substrates  

SciTech Connect (OSTI)

SrO films were grown on LaAlO{sub 3} substrates by molecular beam epitaxy and characterized using reflection high-energy electron diffraction (RHEED) and x-ray diffraction (XRD). The evolution of the RHEED pattern is discussed as a function of film thickness. 500 A thick SrO films were relaxed and exhibited RHEED patterns indicative of an atomically smooth surface having uniform terrace heights. Films had the epitaxial relationship (001){sub SrO}(parallel sign)(001){sub LaAlO{sub 3}}; [010]{sub SrO}(parallel sign)[110]{sub LaAlO{sub 3}}. This 45 deg. in-plane rotation minimizes mismatch and leads to films of high crystalline quality, as verified by Kikuchi lines in the RHEED patterns and narrow rocking curves of the (002) XRD peak.

Maksimov, O.; Heydemann, V. D.; Fisher, P.; Skowronski, M.; Salvador, P. A. [Electro-Optics Center, Pennsylvania State University, Freeport, Pennsylvania 16229 (United States); Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

2006-12-25T23:59:59.000Z

136

The effect of oxygen flow rate and radio frequency plasma power on cubic ZnMgO ultraviolet sensors grown by plasma-enhanced molecular beam epitaxy  

SciTech Connect (OSTI)

Cubic Zn{sub 1-x}Mg{sub x}O thin films were produced by Plasma-Enhanced Molecular Beam Epitaxy. Oxygen flow rate and applied Radio-Frequency (RF) plasma power were varied to investigate the impact on film growth and optoelectronic device performance. Solar-blind and visible-blind detectors were fabricated with metal-semiconductor-metal interdigitated Ni/Mg/Au contacts and responsivity is compared under different growth conditions. Increasing oxygen flow rate and RF plasma power increased Zn incorporation in the film, which leads to phase segregation at relatively high Zn/Mg ratio. Responsivity as high as 61 A/W was measured in phase-segregated ZnMgO visible-blind detectors.

Casey Boutwell, R.; Wei Ming; Schoenfeld, Winston V. [CREOL, College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816-2700 (United States)

2013-07-15T23:59:59.000Z

137

Observation of columnar microstructure in lattice-matched InAlN/GaN grown by plasma assisted molecular beam epitaxy  

SciTech Connect (OSTI)

Nominally lattice matched InAlN/GaN was grown by plasma-assisted molecular beam epitaxy, and the intrinsic microstructure was investigated via x-ray diffraction, transmission electron microscopy, and atom probe tomography. The InAlN showed a cellular structure, which was comprised of {approx}10 nm wide Al-rich cores and {approx}1 nm In-rich InAlN intercellular boundaries. Despite the strong laterally non-uniform In distribution, both vertical and lateral lattices are unperturbed by the cellular structure, as evidenced by strong thickness fringes in on-axis {omega}-2{theta} high resolution x-ray diffraction scans, coherence lengths derived from on-axis (0002) and off-axis (1012) {omega}-2{theta} high resolution x-ray diffraction scans, and a modified Williamson-Hall analysis for on-axis reflections.

Choi, Soojeong; Wu Feng; Shivaraman, Ravi; Young, Erin C.; Speck, James S. [Materials Department, University of California, Santa Barbara, California 93106 (United States)

2012-06-04T23:59:59.000Z

138

Structural and optical characterization of Si{sub x}Ge{sub 1-x-y}Sn{sub y} alloys grown by molecular beam epitaxy  

SciTech Connect (OSTI)

Si{sub x}Ge{sub 1-x-y}Sn{sub y} alloys were grown by molecular beam epitaxy at low temperature, followed by ex-situ annealing. The crystal quality of Si{sub x}Ge{sub 1-x-y}Sn{sub y} layers was characterized by atomic force microscopy and transmission electron microscopy. The compositions and lattice constants of the alloys were studied by x-ray photoelectron spectroscopy and x-ray diffraction. The results show that Vegard's law is a good approximation for Si{sub x}Ge{sub 1-x-y}Sn{sub y} alloys. Photoreflectance spectroscopy at room temperature was used to determine the direct bandgap energy of Si{sub x}Ge{sub 1-x-y}Sn{sub y} layers. Analyzing the relationship between composition and direct bandgap energy reveals a negative energy bowing parameter for SiSn.

Lin, Hai [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Chen, Robert; Huo Yijie; Kamins, Theodore I.; Harris, James S. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Lu Weisheng [Institute of Photonics, University of Strathclyde, Glasgow G4 0NW (United Kingdom)

2012-04-02T23:59:59.000Z

139

Molecular beam deposition of Al{sub 2}O{sub 3} on p-Ge(001)/Ge{sub 0.95}Sn{sub 0.05} heterostructure and impact of a Ge-cap interfacial layer  

SciTech Connect (OSTI)

We investigated the molecular beam deposition of Al{sub 2}O{sub 3} on Ge{sub 0.95}Sn{sub 0.05} surface with and without an ultra thin Ge cap layer in between. We first studied the atomic configuration of both Ge{sub 1-x}Sn{sub x} and Ge/Ge{sub 1-x}Sn{sub x} surfaces after deoxidation by reflection high-energy electron diffraction and resulted, respectively, in a c(4x2) and (2x1) surface reconstructions. After in situ deposition of an Al{sub 2}O{sub 3} high-{kappa} gate dielectric we evidenced using time-of-flight secondary ion mass spectroscopy analyses that Sn diffusion was at the origin of high leakage current densities in the Ge{sub 1-x}Sn{sub x}/Al{sub 2}O{sub 3} gate stack. This damage could be avoided by inserting a thin 5-nm-thick Ge cap between the oxide and the Ge{sub 1-x}Sn{sub x} layer. Finally, metal-oxide-semiconductor capacitors on the Ge capped sample showed well-behaved capacitance-voltage (C-V) characteristics with interface trap density (D{sub it}) in the range of 10{sup 12} eV{sup -1} cm{sup -2} in mid gap and higher close to the valence band edge.

Merckling, C.; Franquet, A.; Vincent, B.; Vandervorst, W.; Loo, R.; Caymax, M. [Interuniversity Microelectronics Center (IMEC vzw), Kapeldreef 75, 3001 Leuven (Belgium); Sun, X. [Katholieke Universiteit Leuven, Celestijnelaan 200D, 3001 Leuven (Belgium); Department of Electrical Engineering, Yale University, New Haven, Connecticut 06520-8284 (United States); Shimura, Y.; Takeuchi, S.; Nakatsuka, O.; Zaima, S. [Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

2011-05-09T23:59:59.000Z

140

Quasibound levels and shape resonances of /sup 39/K/sub 2/(B /sup 1/Pi/sub u/) crossed laser-molecular beam studies and analytical interpretation  

SciTech Connect (OSTI)

Quasibound levels and shape resonances in the (B /sup 1/Pi/sub u/ -X /sup 1/..sigma../sup +//sub g/) band system of /sup 39/K/sub 2/ have been recorded by crossed laser-molecular beam techniques. Using optical--optical double resonance, individual rovibrational levels (v'' = 15--18, J'' = 3--25) of the K/sub 2/ state are prepared by Franck--Condon pumping (FCP) in a supersonic nozzle beam. Excitation into quasibound levels below and above the (B /sup 1/Pi/sub u/) state barrier is detected as molecular and atomic (K4 /sup 2/P/sub 3//sub ///sub 2/..-->..4 /sup 2/S/sub 1//sub ///sub 2/ only) fluorescence. The resonance transition frequencies and shapes are measured and the results are used (a) to determine the scattering resonance energies, widths, and lifetimes; (b) to compare them with values obtained by a ''maximum internal amplitude'' approach (R. J. LeRoy and R. B. Bernstein, J. Chem. Phys. 54, 5114 (1971)); and (c) to check the agreement with exact calculations of the B state potential using the ''inverted perturbation approach (IPA).'' The bound and quasibound part of the B /sup 1/Pi/sub u/ state including the locus (R = 8.08 +- 0.05 A) of the barrier maximum (298 +- 8 cm/sup -1/ above the adiabatic dissociation limit) is found in excellent agreement with previous results. The shape resonances are not highly sensitive to the long-range interatomic forces, here the repulsive dipole--dipole resonance interaction.

Heinze, J.; Kowalczyk, P.; Engelke, F.

1988-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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

Hydrogen-mediated quenching of strain-induced surface roughening during gas-source molecular beam epitaxy of fully-coherent Si0.7Ge0.3  

E-Print Network [OSTI]

Hydrogen-mediated quenching of strain-induced surface roughening during gas-source molecular beam of thickness t at temperatures, Ts 450­550 °C, for which strain-induced roughening is observed during solid scientific and technological reasons. Predicting and minimizing sur- face roughening is required

Spila, Timothy P.

142

The ATLAS3D project XX. Masssize and mass distributions of early-type galaxies: bulge fraction drives kinematics, mass-to-light ratio, molecular gas fraction and stellar initial mass function  

Science Journals Connector (OSTI)

......initial mass function Michele Cappellari 1 Richard M. McDermid 2 Katherine Alatalo 3 Leo Blitz 3 Maxime Bois 4 Frederic Bournaud 5 M...586, 20th Texas Symposium on Relativistic Astrophysics-Wheeler J. C., Martel H., eds. (2001) San Francisco: Astron......

Michele Cappellari; Richard M. McDermid; Katherine Alatalo; Leo Blitz; Maxime Bois; Frdric Bournaud; M. Bureau; Alison F. Crocker; Roger L. Davies; Timothy A. Davis; P. T. de Zeeuw; Pierre-Alain Duc; Eric Emsellem; Sadegh Khochfar; Davor Krajnovic; Harald Kuntschner; Raffaella Morganti; Thorsten Naab; Tom Oosterloo; Marc Sarzi; Nicholas Scott; Paolo Serra; Anne-Marie Weijmans; Lisa M. Young

2013-01-01T23:59:59.000Z

143

Beam History  

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

Beam Status Beam History Print Beamline History Request Form To request a beam current histograph from the ALS storage ring beam histograph database, select the year, month, and...

144

Chemical Analysis of Diesel Engine Nanoparticles Using a Nano-DMA/Thermal Desorption Particle Beam Mass Spectrometer  

Science Journals Connector (OSTI)

Modern combustion engines burn cleaner and produce less particulate mass than older models, but it has also been observed that some engines, for example, diesels, emit high number concentrations of a subset of fine particles called nanoparticles (diameter cycle, turbocharged diesel engine that produced a peak torque of 350 N-m at an intermediate engine speed of 1400 rpm, which is generally used for short-duration work periods of heavy lifting or material handling. ... However, general trends from past studies can be applied to the analysis of this work. ...

Herbert J. Tobias; Derek E. Beving; Paul J. Ziemann; Hiromu Sakurai; Miriam Zuk; Peter H. McMurry; Darrick Zarling; Robert Waytulonis; David B. Kittelson

2001-04-25T23:59:59.000Z

145

Molecular Science Computing | EMSL  

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

Molecular Science Computing Overview Cell Isolation and Systems Analysis Deposition and Microfabrication Mass Spectrometry Microscopy Molecular Science Computing NMR and EPR...

146

Mass Spectrometry | EMSL  

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

and Microfabrication Mass Spectrometry Microscopy Molecular Science Computing NMR and EPR Spectroscopy and Diffraction Subsurface Flow and Transport Mass Spectrometry Systems...

147

Time-of-Flight Secondary Ion Mass Spectrometry Based Molecular Histology of Human Spinal Cord Tissue and Motor Neurons  

Science Journals Connector (OSTI)

Secondary ion mass spectrometry is a powerful method for imaging biological samples with high spatial resolution. Whole section time-of-flight-secondary ion mass spectrometry (TOF-SIMS) scans and multivariate data analysis have been performed on the human ...

Jrg Hanrieder; Per Malmberg; Olle R. Lindberg; John S. Fletcher; Andrew G. Ewing

2013-08-15T23:59:59.000Z

148

Electric-dipole moment of CaF by molecular-beam, laser-rf, double-resonance study of Stark splittings  

SciTech Connect (OSTI)

The electronic structure of diatomic molecules is much more complex for open-shell sytems (radicals) than for the normal closed-shell systems, and the development of an adequate theoretical understanding will require a substantial upgrading of experimental knowledge in both quality and quantity. The alkaline-earth monohalide family of radicals, with only a single electron outside closed-shell cores, would appear to be a logical starting point for such studies, and there has been a great increase in work in this area in the last few years in spite of the special difficulties of working with free radicals. As the work of measuring the vibrational and rotational structure of the electronic states has become more complete, attention has turned to study of the much weaker spin-rotation and hyperfine interactions. Within the last three years, these interactions have been studied systematically at high precision in the calcium monohalide family with the molecular-beam, laser-rf double-resonance technique. The same method has now been modified and extended to make possible measurement of the electric-dipole moments of these molecules through observation of the Stark splittings of radiofrequency transitions. It is hoped that when considered together, the several types of data will make it possible to understand the ground-state electronic wave functions of these molecules at least qualitatively. 2 figures.

Childs, W.J.; Goodman, L.S.; Nielsen, U.; Pfeufer, V.

1984-01-01T23:59:59.000Z

149

Molecular beam epitaxial growth and characterization of mixed (Ti,Nb)O{sub 2} rutile films on TiO{sub 2}(100)  

SciTech Connect (OSTI)

Epitaxial films of mixed (Nb,Ti)O{sub 2} rutile have been grown on TiO{sub 2}(100) rutile at 600{degree}C by molecular beam epitaxy. These films grow in a laminar fashion for Nb mole fractions up to {approximately}0.10. In addition, reflection high-energy and low-energy electron diffraction, along with x-ray photoelectron diffraction and Rutherford backscattering reveal that the overlayers possess excellent long- and short-range structure order up to 10 at.{percent}. However, strain-induced disorder becomes prevalent for higher Nb mole fractions, and the surfaces roughen and become defected accordingly. X-ray photoelectron diffraction and Rutherford backscattering reveal that Nb atoms substitutionally incorporate at cation sites in the rutile lattice for all Nb mole fractions investigated, leading to a mixed rutile Nb{sub {ital x}}Ti{sub 1{minus}{ital x}}O{sub 2} phase. Analysis of Nb 3{ital d} and Ti 2{ital p} core-level binding energies reveals that the oxidation state of both Ti and Nb is +4. {copyright} {ital 1996 American Vacuum Society}

Chambers, S.A.; Gao, Y.; Thevuthasan, S.; Liang, Y. [Environmental Molecular Sciences Laboratory, Pacific Northwest Laboratory, Richland, Washington 99352 (United States)] [Environmental Molecular Sciences Laboratory, Pacific Northwest Laboratory, Richland, Washington 99352 (United States); Shivaparan, N.R.; Smith, R.J. [Department of Physics, Montana State University, Bozeman, Montana 59717 (United States)] [Department of Physics, Montana State University, Bozeman, Montana 59717 (United States)

1996-05-01T23:59:59.000Z

150

Homogeneous AlGaN/GaN superlattices grown on free-standing (1100) GaN substrates by plasma-assisted molecular beam epitaxy  

SciTech Connect (OSTI)

Two-dimensional and homogeneous growth of m-plane AlGaN by plasma-assisted molecular beam epitaxy has been realized on free-standing (1100) GaN substrates by implementing high metal-to-nitrogen (III/N) flux ratio. AlN island nucleation, often reported for m-plane AlGaN under nitrogen-rich growth conditions, is suppressed at high III/N flux ratio, highlighting the important role of growth kinetics for adatom incorporation. The homogeneity and microstructure of m-plane AlGaN/GaN superlattices are assessed via a combination of scanning transmission electron microscopy and high resolution transmission electron microscopy (TEM). The predominant defects identified in dark field TEM characterization are short basal plane stacking faults (SFs) bounded by either Frank-Shockley or Frank partial dislocations. In particular, the linear density of SFs is approximately 5 10{sup ?5} cm{sup ?1}, and the length of SFs is less than 15 nm.

Shao, Jiayi; Malis, Oana [Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States) [Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Physics Department, Purdue University, West Lafayette, Indiana 47907 (United States); Zakharov, Dmitri N. [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973 (United States)] [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973 (United States); Edmunds, Colin [Physics Department, Purdue University, West Lafayette, Indiana 47907 (United States)] [Physics Department, Purdue University, West Lafayette, Indiana 47907 (United States); Manfra, Michael J. [Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States) [Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Physics Department, Purdue University, West Lafayette, Indiana 47907 (United States); School of Materials Engineering, Purdue University, West Lafayette, Indiana 49707 (United States); School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 49707 (United States)

2013-12-02T23:59:59.000Z

151

Design of an ultrahigh vacuum transfer mechanism to interconnect an oxide molecular beam epitaxy growth chamber and an x-ray photoemission spectroscopy analysis system  

SciTech Connect (OSTI)

We designed a mechanism and the accompanying sample holders to transfer between a VEECO 930 oxide molecular beam epitaxy (MBE) and a PHI Versa Probe X-ray photoemission spectroscopy (XPS) chamber within a multiple station growth, processing, and analysis system through ultrahigh vacuum (UHV). The mechanism consists of four parts: (1) a platen compatible with the MBE growth stage, (2) a platen compatible with the XPS analysis stage, (3) a sample coupon that is transferred between the two platens, and (4) the accompanying UHV transfer line. The mechanism offers a robust design that enables transfer back and forth between the growth chamber and the analysis chamber, and yet is flexible enough to allow transfer between standard sample holders for thin film growth and masked sample holders for making electrical contacts and Schottky junctions, all without breaking vacuum. We used this mechanism to transfer a barium strontium titanate thin film into the XPS analysis chamber and performed XPS measurements before and after exposing the sample to the air. After air exposure, a thin overlayer of carbon was found to form and a significant shift ({approx}1 eV) in the core level binding energies was observed.

Rutkowski, M. M.; Zeng Zhaoquan [Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States); McNicholas, K. M. [Department of Electrical and Computer Engineering, Ohio State University, Columbus, Ohio 43210 (United States); Brillson, L. J. [Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States); Department of Electrical and Computer Engineering, Ohio State University, Columbus, Ohio 43210 (United States)

2013-06-15T23:59:59.000Z

152

Energy band alignment of atomic layer deposited HfO{sub 2} on epitaxial (110)Ge grown by molecular beam epitaxy  

SciTech Connect (OSTI)

The band alignment properties of atomic layer HfO{sub 2} film deposited on epitaxial (110)Ge, grown by molecular beam epitaxy, was investigated using x-ray photoelectron spectroscopy. The cross-sectional transmission electron microscopy exhibited a sharp interface between the (110)Ge epilayer and the HfO{sub 2} film. The measured valence band offset value of HfO{sub 2} relative to (110)Ge was 2.28 {+-} 0.05 eV. The extracted conduction band offset value was 2.66 {+-} 0.1 eV using the bandgaps of HfO{sub 2} of 5.61 eV and Ge bandgap of 0.67 eV. These band offset parameters and the interface chemical properties of HfO{sub 2}/(110)Ge system are of tremendous importance for the design of future high hole mobility and low-power Ge-based metal-oxide transistor devices.

Hudait, M. K.; Zhu, Y. [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States); Maurya, D.; Priya, S. [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)

2013-03-04T23:59:59.000Z

153

Electrical spin injection into InGaAs/GaAs quantum wells: A comparison between MgO tunnel barriers grown by sputtering and molecular beam epitaxy methods  

SciTech Connect (OSTI)

An efficient electrical spin injection into an InGaAs/GaAs quantum well light emitting diode is demonstrated thanks to a CoFeB/MgO spin injector. The textured MgO tunnel barrier is fabricated by two different techniques: sputtering and molecular beam epitaxy. The maximal spin injection efficiency is comparable for both methods. Additionally, the effect of annealing is also investigated for the two types of samples. Both samples show the same trend: an increase of the electroluminescence circular polarization (P{sub c}) with the increase of annealing temperature, followed by a saturation of P{sub c} beyond 350?C annealing. Since the increase of P{sub c} starts well below the crystallization temperature of the full CoFeB bulk layer, this trend could be mainly due to an improvement of chemical structure at the top CoFeB/MgO interface. This study reveals that the control of CoFeB/MgO interface is essential for an optimal spin injection into semiconductor.

Barate, P.; Zhang, T. T.; Vidal, M.; Renucci, P.; Marie, X.; Amand, T. [Universit de Toulouse, INSA-CNRS-UPS, LPCNO, 135 avenue de Rangueil, 31077 Toulouse (France); Liang, S.; Devaux, X.; Hehn, M.; Mangin, S.; Lu, Y., E-mail: yuan.lu@univ-lorraine.fr [Institut Jean Lamour, UMR 7198, CNRS-Nancy Universit, BP 239, 54506 Vandoeuvre (France); Frougier, J.; Jaffrs, H.; George, J. M. [Unit Mixte de Physique CNRS/Thales and Universit Paris-Sud 11, 1 avenue A. Fresnel, 91767 Palaiseau (France); Xu, B.; Wang, Z. [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P. O. Box 912, Beijing 100083 (China); Zheng, Y. [Institut des NanoSciences de Paris, UPMC, CNRS UMR 7588, 4 place Jussieu, 75005 Paris (France); Tao, B. [Institut Jean Lamour, UMR 7198, CNRS-Nancy Universit, BP 239, 54506 Vandoeuvre (France); Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190 (China); Han, X. F. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190 (China)

2014-07-07T23:59:59.000Z

154

Electronic structure, morphology and emission polarization of enhanced symmetry InAs quantum-dot-like structures grown on InP substrates by molecular beam epitaxy  

SciTech Connect (OSTI)

The optical and structural properties of a new kind of InAs/InGaAlAs/InP quantum dot (QD)-like objects grown by molecular beam epitaxy have been investigated. These nanostructures were found to have significantly more symmetrical shapes compared to the commonly obtained dash-like geometries typical of this material system. The enhanced symmetry has been achieved due to the use of an As{sub 2} source and the consequent shorter migration length of the indium atoms. Structural studies based on a combination of scanning transmission electron microscopy (STEM) and atom probe tomography (APT) provided detailed information on both the structure and composition distribution within an individual nanostructure. However, it was not possible to determine the lateral aspect ratio from STEM or APT. To verify the in-plane geometry, electronic structure calculations, including the energy levels and transition oscillator strength for the QDs have been performed using an eight-band kp model and realistic system parameters. The results of calculations were compared to measured polarization-resolved photoluminescence data. On the basis of measured degree of linear polarization of the surface emission, the in-plane shape of the QDs has been assessed proving a substantial increase in lateral symmetry. This results in quantum-dot rather than quantum-dash like properties, consistent with expectations based on the growth conditions and the structural data.

Mary?ski, A.; S?k, G.; Musia?, A.; Andrzejewski, J.; Misiewicz, J. [Institute of Physics, Wroc?aw University of Technology, Wybrze?e Wyspia?skiego 27, 50-370 Wroc?aw (Poland)] [Institute of Physics, Wroc?aw University of Technology, Wybrze?e Wyspia?skiego 27, 50-370 Wroc?aw (Poland); Gilfert, C.; Reithmaier, J. P. [Technische Physik, Institute of Nanostructure Technology and Analytics, CINSaT, University of Kassel, Heinrich Plett-Str. 40, D-34132 Kassel (Germany)] [Technische Physik, Institute of Nanostructure Technology and Analytics, CINSaT, University of Kassel, Heinrich Plett-Str. 40, D-34132 Kassel (Germany); Capua, A.; Karni, O.; Gready, D.; Eisenstein, G. [Department of Electrical Engineering, Technion, Haifa 32000 (Israel)] [Department of Electrical Engineering, Technion, Haifa 32000 (Israel); Atiya, G.; Kaplan, W. D. [Department of Materials Science and Engineering, Technion, Haifa 32000 (Israel)] [Department of Materials Science and Engineering, Technion, Haifa 32000 (Israel); Klling, S. [Fraunhofer Institute for Photonic Microsystems, Center for Nanoelectronic Technologies, Knigsbrcker Strae 180, D-01099 Dresden (Germany)] [Fraunhofer Institute for Photonic Microsystems, Center for Nanoelectronic Technologies, Knigsbrcker Strae 180, D-01099 Dresden (Germany)

2013-09-07T23:59:59.000Z

155

Enhanced production of runaway electrons during electron cyclotron resonance heating and in the presence of supersonic molecular beam injection in the HL-2A tokamak  

SciTech Connect (OSTI)

In the present paper, it is reported that a large production of runaway electrons has been observed during the flattop phase of electron cyclotron resonance heating (ECRH) discharges and in the presence of supersonic molecular beam injection (SMBI) in the HuanLiuqi-2A (commonly referred to as HL-2A) [Q. W. Yang, Nucl. Fusion 47, S635 (2007)] tokamak. For the set of discharges carried out in the present experiment, the ranges of ECRH power and plasma electron density are 0.8-1.0 MW and (3.0-4.0)x10{sup 19} m{sup -3}, respectively. A large number of superthermal electrons are produced through the avalanche effect [A. Lazaros, Phys. Plasmas 8, 1263 (2001)] during ECRH. The loop voltage increase due to SMBI gives rise to a decline in the critical runaway energy, which leads to that many superthermal electrons could be converted into runaway region. Therefore, this phenomenon may come from the synergetic effects of ECRH and SMBI. That is, the superthermal electrons created by ECRH are accelerated into runaway regime via the Dreicer process which is triggered by SMBI. The experimental results are in well agreement with the calculational ones based on the superthermal electron avalanche effect and the Dreicer runaway theory.

Zhang, Y. P.; Liu, Yi; Yang, J. W.; Song, X. Y.; Yuan, G. L.; Zhou, J.; Yao, L. H.; Feng, B. B.; Li, X.; Yang, Q. W.; Duan, X. R.; Pan, C. H.; Liu, Y. [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China)

2010-07-15T23:59:59.000Z

156

Photoacoustic signals of n-type GaAs layers grown by molecular-beam epitaxy on semi-insulating substrates  

Science Journals Connector (OSTI)

Piezoelectric photoacoustic (PA) measurements of molecular-beam-epitaxial (MBE) -grown GaAs layers were carried out in the temperature range from 90 to 290 K. A broad D band with a maximum near 1.3 eV and a sharp Q peak at 1.485 eV have been observed in the 90-K spectra. They vanish in a presence of secondary light illumination. By comparing with optical-absorption spectra, it is considered that the D band is due to electron transitions involving EL2 deep defect levels in the GaAs substrate. The PA signal is considered to be enhanced by the presence of the electric field at the interface between the MBE layer and the substrate. The Q peak is attributed to electron transitions from shallow acceptors such as carbon in GaAs. Observed photoinduced changes in the spectra are explained by a reduction of the electric field in the depletion region which is induced by optical carrier generation.

T. Ikari; A. Fukuyama; K. Maeda; K. Futagami; S. Shigetomi; Y. Akashi

1992-10-15T23:59:59.000Z

157

Beam History  

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

Beam History Print Beamline History Request Form To request a beam current histograph from the ALS storage ring beam histograph database, select the year, month, and day, then...

158

Molecular Foundry  

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

See the Foundry's full equipment list See the Foundry's full equipment list Nanofabrication Capabilities & Tools Major Capabilities: Instruments and Labs Zeiss Crossbeam 1540 EsB The Molecular Foundry Zeiss Cross-beam is one of the most versatile lithographic and inspection tools allowing fabrication of complex prototypes for nanoelectronics, nano-optical antenna, modifying scanning probe tips, rapid electrical contacting and many other applications. The 1500XB Cross Beam combines the Gemini field emission column (FESEM) with the Orsay Physics focused ion beam (FIB). In addition, the instrument offers a multi-channel gas injection system to allow ion and electron beam induced deposition (IBID and EBID) and chemically assisted ion beam etching (CAIBE). The tool can be used for lithographic patterning of materials or

159

Automated probe microdistillation/mass spectrometry for the analysis of high-molecular weight compounds in fossil fuels  

SciTech Connect (OSTI)

Automated probe microdistillation/mass spectroscopy is described. The application of computer hardware and the development of computer software eliminate the dilatory nature of acquiring both the temperature and associated mass spectra and reduces the acquired data for processing. The interaction of various hardware components of the system as well as the associated software is described. (DMC)

Scheppele, S.E.; Grindstaff, Q.G.; Grigsby, R.D.; Chung, K.C.; Hwang, C.S.; Marriott, T.D.; Schronk, L.R.

1982-08-01T23:59:59.000Z

160

The use the a high intensity neutrino beam from the ESS proton linac for measurement of neutrino CP violation and mass hierarchy  

E-Print Network [OSTI]

It is proposed to complement the ESS proton linac with equipment that would enable the production, concurrently with the production of the planned ESS beam used for neutron production, of a 5 MW beam of 10$^{23}$ 2.5 GeV protons per year in microsecond short pulses to produce a neutrino Super Beam, and to install a megaton underground water Cherenkov detector in a mine to detect $\

Baussan, E; Ekelof, T; Martinez, E Fernandez; Ohman, H; Vassilopoulos, N

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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

The use of a high intensity neutrino beam from the ESS proton linac for measurement of neutrino CP violation and mass hierarchy  

E-Print Network [OSTI]

It is proposed to complement the ESS proton linac with equipment that would enable the production, concurrently with the production of the planned ESS beam used for neutron production, of a 5 MW beam of 10$^{23}$ 2.5 GeV protons per year in microsecond short pulses to produce a neutrino Super Beam, and to install a megaton underground water Cherenkov detector in a mine to detect $\

E. Baussan; M. Dracos; T. Ekelof; E. Fernandez Martinez; H. Ohman; N. Vassilopoulos

2013-02-09T23:59:59.000Z

162

PHOTOELECTRON PHOTOION MOLECULAR BEAM SPECTROSCOPY  

E-Print Network [OSTI]

that are compatible with the UHV environments necessary toare not compatible with this UHV environment, such as, gasespressure sample region to the UHV region of the radiation

Trevor, Dennis J.

2010-01-01T23:59:59.000Z

163

Molecular Science Computing Policies | EMSL  

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

and Microfabrication Mass Spectrometry Microscopy Molecular Science Computing NMR and EPR Spectroscopy and Diffraction Subsurface Flow and Transport Molecular Science Computing...

164

Colliding neutrino beams  

E-Print Network [OSTI]

From several neutrino oscillation experiments, we understand now that neutrinos have mass. However, we really don't know what mechanism is responsible for producing this neutrino mass. Current or planned neutrino experiments utilize neutrino beams and long-baseline detectors to explore flavor mixing but do not address the question of the origin of neutrino mass. In order to answer that question, neutrino interactions need to be explored at much higher energies. This paper outlines a program to explore neutrinos and their interactions with various particles through a series of experiments involving colliding neutrino beams.

Reinhard Schwienhorst

2007-11-08T23:59:59.000Z

165

Effects of anthropogenic activities on the molecular composition of urban organic aerosols: an ultrahigh resolution mass spectrometry study  

E-Print Network [OSTI]

of Chemistry, Aarhus University, Aarhus, DK-8000, Denmark 11 4Department of Analytical Chemistry, Ghent University, Krijgslaan 281, S12, BE-9000 12 Ghent, Belgium 13 5Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, BE-14... ). 95 The objective of the current study is to apply nanoESI UHRMS to determine the molecular 96 composition of urban PM2.5 (particles with ?2.5m). Aerosol samples were collected at the 97 industrial site in Cork Ireland during summer with the aim...

Kourtchev, I.; O'Connor, I. P.; Giorio, C.; Fuller, S.; Kristenen, K.; Maenhaut, W.; Wenger, J. C.; Sodeau, J. R.; Glasius, M.; Kalberer, M.

2014-02-23T23:59:59.000Z

166

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...

167

Molecular Foundry  

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

See the Foundry's full equipment list See the Foundry's full equipment list Organic and Macromolecular Synthesis Capabilities & Tools Major Instruments and Capabilities AB SCIEX TF4800 MALDI TOF-TOF Mass Spectrometer This instrument is the tandem time-of-flight mass spectrometer systems, providing the excellent level of molecular mass coverage in the range of molecular masses 500 and 150,000 Da, high throughput, and confidence in both qualitative and quantitative analyses. The analyzer combines all of the advantages of MALDI in a flexible, easy-to-use, ultra-high-performance mass spectrometer with all the advanced capabilities of software. On-axis laser provides high sensitivity to identify and quantitate low-abundance compounds in complex samples. High-resolution precursor ion selection lets

168

Electrospray ionizationtandem mass spectrometry analysis of phospholipid molecular species from Antarctic and non-Antarctic yeasts  

Science Journals Connector (OSTI)

Abstract High performance liquid chromatography-electrospray ionization tandem mass spectrometry was applied to the comprehensive analysis of phospholipids from seven Antarctic and seven non-Antarctic yeasts. Identification of specific fatty acyl moieties to the sn-1 and sn-2 positions of phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine (PS) and phosphatidylinositol (PI) were determined by relative abundance of fragment ions associated with formation of carboxylate anions and loss of fragment ions as free fatty carboxylic acid and ketene. Modulations with growth temperature in fatty acyl moieties in the sn-1 and sn-2 positions were characterized. Principal component analysis demonstrated that PE, PC and to a lesser extent PS, but not PI, were grouped into three distinct clusters consisting of seven Antarctic yeasts (Cryptococcus victoriae, Holtermanniella wattica, H. nyarrowii, Candida psychrophila, Leucosporidium fellii, Glaciozyma antarctica, Rhodotorula mucilaginosa), four non-Antarctic yeasts (C. albicans, Zygosaccharomyces rouxii, Cr. humicolus, R. mucilaginosa) and three strains of Saccharomyces cerevisiae.

Mohammad Bhuiyan; David Tucker; Kenneth Watson

2014-01-01T23:59:59.000Z

169

Crossed Molecular Beams Study on the Formation of Vinylacetylene in Titan's Atmosphere Fangtong Zhang, Yong Seol Kim, and Ralf I. Kaiser*  

E-Print Network [OSTI]

), was investigated at a collision energy of 20.6 ( 0.4 kJ mol-1 utilizing the crossed-beams technique. Combined such as Titan's atmosphere via the neutral-neutral reaction of ethynyl radicals with ubiquitous ethylene and their role in the build-

Kaiser, Ralf I.

170

High-efficiency GaAs and GaInP solar cells grown by all solid-state molecular-beam-epitaxy  

Science Journals Connector (OSTI)

We report the initial results of GaAs and GaInP solar cells grown by all solid-state molecular- ... (MBE) technique. For GaAs single-junction solar cell, with the application of AlInP as ... back surface field la...

Shulong Lu; Lian Ji; Wei He; Pan Dai; Hui Yang

2011-10-01T23:59:59.000Z

171

Studies on Biological Effects of Ion Beams on Lethality, Molecular Nature of Mutation, Mutation Rate, and Spectrum of Mutation Phenotype for Mutation Breeding in Higher Plants  

Science Journals Connector (OSTI)

......rearrangements preferably induced by car- bon ions have different molecular...mutant, suv2-1, which is defective in cell-cycle arrest in response...Rearrangement of the DNA in car- bon ion-induced mutants...mutant in Arabidopsis thaliana is defective in the DNA damage response......

Atsushi Tanaka; Naoya Shikazono; Yoshihiro Hase

2010-05-01T23:59:59.000Z

172

Low energy beta-beams  

E-Print Network [OSTI]

The main goal of a beta-beam facility is to determine the possible existence of CP violation in the lepton sector, the value of the third neutrino mixing angle and the mass hierarchy. Here we argue that a much broader physics case can be covered since the beta-beam concept can also be used to establish a low energy beta-beam facility. We discuss that the availability of neutrino beams in the 100 MeV energy range offers a unique opportunity to perform neutrino scattering experiments of interest for nuclear physics, for the study of fundamental interactions and of core-collapse supernova physics.

Cristina Volpe

2009-11-13T23:59:59.000Z

173

Airfoil sampling of a pulsed Laval beam with tunable vacuum ultraviolet (VUV) synchrotron ionization quadrupole mass spectrometry: Application to low--temperature kinetics and product detection  

SciTech Connect (OSTI)

A new pulsed Laval nozzle apparatus with vacuum ultraviolet (VUV) synchrotron photoionization quadrupole mass spectrometry is constructed to study low-temperature radicalneutralchemical reactions of importance for modeling the atmosphere of Titan and the outer planets. A design for the sampling geometry of a pulsed Laval nozzle expansion has beendeveloped that operates successfully for the determination of rate coefficients by time-resolved mass spectrometry. The new concept employs airfoil sampling of the collimated expansion withexcellent sampling throughput. Time-resolved profiles of the high Mach number gas flow obtained by photoionization signals show that perturbation of the collimated expansion by theairfoil is negligible. The reaction of C2H with C2H2 is studied at 70 K as a proof-of-principle result for both low-temperature rate coefficient measurements and product identification basedon the photoionization spectrum of the reaction product versus VUV photon energy. This approach can be used to provide new insights into reaction mechanisms occurring at kinetic ratesclose to the collision-determined limit.

Soorkia, Satchin; Liu, Chen-Lin; Savee, John D.; Ferrell, Sarah J.; Leone, Stephen R.; Wilson, Kevin R.

2011-10-12T23:59:59.000Z

174

Molecular Characterization of Biomass Burning Aerosols Using...  

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

Biomass Burning Aerosols Using High Resolution Mass Spectrometry. Molecular Characterization of Biomass Burning Aerosols Using High Resolution Mass Spectrometry. Abstract: Chemical...

175

Potential for Higher Treatment Failure in Obese Patients: Correlation of Elevated Body Mass Index and Increased Daily Prostate Deviations From the Radiation Beam Isocenters in an Analysis of 1,465 Computed Tomographic Images  

SciTech Connect (OSTI)

Purpose: Recent clinical outcome studies on prostate cancer have reported the influence of patient's obesity on the biochemical failure rates after various treatment modalities. In this study, we investigated the effect of patient's physical characteristics on prostate shift in external beam radiotherapy (EBRT) and hypothesized that there maybe a correlation between patient physique and tumor shift. Methods and Materials: A retrospective analysis was performed using data for 117 patients who received image-guided radiation therapy (IGRT) for prostate cancer between January 2005 and April 2007. A total of 1,465 CT scans were analyzed. The standard deviations (SDs) of prostate shifts for all patients, along with patient weight, body mass index (BMI), and subcutaneous adipose-tissue thickness (SAT), were determined. Spearman rank correlation analysis was performed. Results: Of the 117 patients, 26.5% were considered normal weight, 48.7% were overweight, 17.9% were mildly obese, and 6.9% were moderately to severely obese. Notably 1.3%, 1.5%, 2.0%, and 21.2% of the respective shifts were greater than 10 mm in the left-right (LR) direction for the four patient groups, whereas in the anterior-posterior direction the shifts are 18.2%, 12.6%, 6.7%, and 21.0%, respectively. Strong correlations were observed between SAT, BMI, patient weight, and SDs of daily shifts in the LR direction (p < 0.01). Conclusions: The strong correlation between obesity and shift indicates that without image-guided radiation therapy, the target volume (prostate with or without seminal vesicles) may not receive the intended dose for patients who are moderate to severely obese. This may explain the higher recurrence rate with conventional external beam radiation therapy.

Wong, James R. [Department of Radiation Oncology, Carol G. Simon Cancer Center, Morristown Memorial Hospital, Morristown, NJ (United States)], E-mail: jackie.vizoso@atlantichealth.org; Gao Zhanrong; Merrick, Scott; Wilson, Paula [Department of Radiation Oncology, Carol G. Simon Cancer Center, Morristown Memorial Hospital, Morristown, NJ (United States); Uematsu, Minoru [Radiation Oncology, Uematsu-Atsuchi-Serendipity Oncology Center, Terukuni, Kagoshima (Japan); Woo, Kevin; Cheng, C.-W. [Department of Radiation Oncology, The Carol G. Simon Cancer Center, Morristown Memorial Hospital, Morristown, NJ (United States)

2009-09-01T23:59:59.000Z

176

Steric effects in molecular adsorption  

SciTech Connect (OSTI)

The results of a molecular beam surface scattering experiment with preferentially orientated NO on Ag(111) are given. In adsorption molecules oriented with the O end towards the surface have a larger trapping probability.

Tenner, M.G.; Kuipers, E.W.; Kleyn, A.W.; Stolte, S.

1988-11-15T23:59:59.000Z

177

Structure and magnetism in strained Ge{sub 1-x-y}Sn{sub x}Mn{sub y} films grown on Ge(001) by low temperature molecular beam epitaxy  

SciTech Connect (OSTI)

In this letter, we study the structural and magnetic properties of Ge{sub 1-x-y}Sn{sub x}Mn{sub y} films grown on Ge(001) by low temperature molecular beam epitaxy using X-ray diffraction, high resolution transmission electron microscopy, and superconducting quantum interference device. Like in Mn doped Ge films, Mn atoms diffuse during the growth and aggregate into vertically aligned Mn-rich nanocolumns of a few nanometers in diameter. Transmission electron microscopy observations in plane view clearly indicate that the Sn incorporation is not uniform with concentration in Mn rich vertical nanocolumns lower than the detection limit of electron energy loss spectroscopy. The matrix exhibits a GeSn solid solution while there is a Sn-rich GeSn shell around GeMn nanocolumns. The magnetization in Ge{sub 1-x-y}Sn{sub x}Mn{sub y} layers is higher than in Ge{sub 1-x}Mn{sub x} films. This magnetic moment enhancement in Ge{sub 1-x-y}Sn{sub x}Mn{sub y} is probably related to the modification of the electronic structure of Mn atoms in the nanocolumns by the Sn-rich shell, which is formed around the nanocolumns.

Prestat, E. [INAC, SP2M, CEA and Universite Joseph Fourier, 17 rue des Martyrs, 38054 Grenoble (France); Karlsruher Institut fuer Technologie (KIT), Laboratorium fuer Elektronenmikroskopie, D-76128 Karlsruhe (Germany); Barski, A.; Bellet-Amalric, E.; Morel, R.; Tainoff, D.; Jain, A.; Porret, C.; Bayle-Guillemaud, P.; Jamet, M. [INAC, SP2M, CEA and Universite Joseph Fourier, 17 rue des Martyrs, 38054 Grenoble (France); Jacquot, J.-F. [INAC, SCIB, CEA and Universite Joseph Fourier, 17 rue des Martyrs, 38054 Grenoble (France)

2013-07-01T23:59:59.000Z

178

Laser postionization secondary neutral mass spectrometry in tissue: a powerful tool for elemental and molecular imaging in the development of targeted drugs  

Science Journals Connector (OSTI)

...32 Chandra S, Lorey DRI, Smith DR. Quantitative subcellular secondary ion mass spectrometry (SIMS) imaging of boron-10 and boron-11 isotopes in the same cell delivered by two combined BNCT drugs: in vitro studies on human glioblastoma...

Andrea Wittig; Heinrich F. Arlinghaus; Christian Kriegeskotte; Raymond L. Moss; Klaas Appelman; Kurt W. Schmid; Wolfgang A.G. Sauerwein

2008-07-01T23:59:59.000Z

179

Structural and band alignment properties of Al{sub 2}O{sub 3} on epitaxial Ge grown on (100), (110), and (111)A GaAs substrates by molecular beam epitaxy  

SciTech Connect (OSTI)

Structural and band alignment properties of atomic layer Al{sub 2}O{sub 3} oxide film deposited on crystallographically oriented epitaxial Ge grown in-situ on (100), (110), and (111)A GaAs substrates using two separate molecular beam epitaxy chambers were investigated using cross-sectional transmission microscopy (TEM) and x-ray photoelectron spectroscopy (XPS). High-resolution triple axis x-ray measurement demonstrated pseudomorphic and high-quality Ge epitaxial layer on crystallographically oriented GaAs substrates. The cross-sectional TEM exhibited a sharp interface between the Ge epilayer and each orientation of the GaAs substrate as well as the Al{sub 2}O{sub 3} film and the Ge epilayer. The extracted valence band offset, {Delta}E{sub v}, values of Al{sub 2}O{sub 3} relative to (100), (110), and (111) Ge orientations using XPS measurement were 3.17 eV, 3.34 eV, and 3.10 eV, respectively. Using XPS data, variations in {Delta}E{sub v} related to the crystallographic orientation were {Delta}E{sub V}(110)Ge>{Delta}E{sub V}(100)Ge{>=}{Delta}E{sub V}(111)Ge and the conduction band offset, {Delta}E{sub c}, related to the crystallographic orientation was {Delta}E{sub c}(111)Ge>{Delta}E{sub c}(110)Ge>{Delta}E{sub c}(100)Ge using the measured {Delta}E{sub v}, bandgap of Al{sub 2}O{sub 3} in each orientation, and well-known Ge bandgap of 0.67 eV. These band offset parameters are important for future application of Ge-based p- and n-channel metal-oxide field-effect transistor design.

Hudait, M. K.; Zhu, Y. [Advanced Devices and Sustainable Energy Laboratory (ADSEL), Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States); Maurya, D.; Priya, S. [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Patra, P. K. [Department of Biomedical Engineering and Department of Mechanical Engineering, University of Bridgeport, Bridgeport, Connecticut 06604 (United States); Ma, A. W. K. [Department of Chemical and Biomolecular Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Aphale, A.; Macwan, I. [Department of Electrical and Computer Engineering, University of Bridgeport, Bridgeport, Connecticut 06604 (United States)

2013-04-07T23:59:59.000Z

180

Mass of Cd104  

Science Journals Connector (OSTI)

A quadrupole-dipole-dipole-dipole spectrograph has been used with a 34.6 MeV proton beam to observe the Cd106(p,t)Cd104 reaction. The Q value is measured and a mass excess of -83 963(14) keV is inferred for Cd104.NUCLEAR REACTIONS Cd106(p,t)Cd104, E=34.6 MeV; Q value measured; mass excess inferred.

R. A. Dewberry; R. T. Kouzes; R. A. Naumann

1983-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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.


181

Probing Molecular Associations of Field-Collected and Laboratory...  

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

Molecular Associations of Field-Collected and Laboratory-Generated SOA with Nano-DESI High-Resolution Mass Spectrometry. Probing Molecular Associations of Field-Collected and...

182

BEAM LINE  

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

BEAM LINE BEAM LINE 45 W ILHELM ROENTGEN'S INITIAL DISCOVERY of X-radiation in 1895 led immediately to practical applications in medicine. Over the next few decades X rays proved to be an invaluable tool for the investigation of the micro-world of the atom and the development of the quantum theory of matter. Almost a century later, telescopes designed to detect X-radiation are indispensable for understanding the structure and evolution of the macro-world of stars, galaxies, and the Universe as a whole. The X-Ray Universe by WALLACE H. TUCKER X-ray images of the Universe are strikingly different from the usual visible-light images. 46 SUMMER 1995 did not think: I investigated." Undeterred by NASA's rejection of a proposal to search for cosmic X-radiation, Giacconi persuaded the

183

In situ secondary ion mass spectrometry analysis  

SciTech Connect (OSTI)

The direct detection of tributyl phosphate (TBP) on rocks using molecular beam surface analysis [MBSA or in situ secondary ion mass spectrometry (SIMS)] is demonstrated. Quantities as low as 250 ng were detected on basalt and sandstone with little or no sample preparation. Detection of TBP on soil has proven to be more problematic and requires further study. Ethylenediaminetetraacetic acid (EDTA) is more difficult to detect because it is very reactive with surfaces of interest. Nevertheless, it is possible to detect EDTA if the acidity of the surface is controlled. The detection of EDTA-metal complexes is currently an open question, but evidence is presented for the detection of ions arising from a EDTA-lead complex. Carboxylic acids (i.e., citric, ascorbic, malic, succinic, malonic, and oxalic) give characteristic SIM spectra, but their detection on sample surfaces awaits evaluation.

Groenewold, G.S.; Applehans, A.D.; Ingram, J.C.; Delmore, J.E.; Dahl, D.A.

1993-01-01T23:59:59.000Z

184

Molecular Chemistry of Organic Aerosols Through the Application...  

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

Chemistry of Organic Aerosols Through the Application of High Resolution Mass Spectrometry. Molecular Chemistry of Organic Aerosols Through the Application of High Resolution Mass...

185

Beam-Bem interactions  

SciTech Connect (OSTI)

In high energy storage-ring colliders, the nonlinear effect arising from beam-beam interactions is a major source that leads to the emittance growth, the reduction of beam life time, and limits the collider luminosity. In this paper, two models of beam-beam interactions are introduced, which are weak-strong and strong-strong beam-beam interactions. In addition, space-charge model is introduced.

Kim, Hyung Jin; /Fermilab

2011-12-01T23:59:59.000Z

186

E-Print Network 3.0 - atlas combined beam Sample Search Results  

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

Charged-particle multiplicities ... Source: Titov, Anatoly - Laboratory of Molecular Beams, Petersburg Nuclear Physics Institute Collection: Physics 2 ATLAS ATLAS ATLAS ATLAS...

187

Proposal of physics with exotic beams at Oak Ridge  

SciTech Connect (OSTI)

A facility to produce proton-rich radioactive beams for nuclear structure and astrophysics experiments is proposed. This Oak Ridge Exotic Beam (OREB) facility is based on two existing accelerators. Beams of mass up to 80 can be accelerated to energies of about 5 MeV/nucleon. It will provide opportunities to study new areas in nuclear physics and astrophysics that are not available with the use of stable beams. 3 figs.

Lee, I-Yang.

1991-01-01T23:59:59.000Z

188

X-ray beam finder  

DOE Patents [OSTI]

An X-ray beam finder for locating a focal spot of an X-ray tube includes a mass of X-ray opaque material having first and second axially-aligned, parallel-opposed faces connected by a plurality of substantially identical parallel holes perpendicular to the faces and a film holder for holding X-ray sensitive film tightly against one face while the other face is placed in contact with the window of an X-ray head.

Gilbert, H.W.

1983-06-16T23:59:59.000Z

189

Wave mechanics of a two-wire atomic beam splitter  

SciTech Connect (OSTI)

We consider the problem of an atomic beam propagating quantum mechanically through an atom beam splitter. Casting the problem in an adiabatic representation (in the spirit of the Born-Oppenheimer approximation in molecular physics) sheds light on explicit effects due to nonadiabatic passage of the atoms through the splitter region. We are thus able to probe the fully three-dimensional structure of the beam splitter, gathering quantitative information about mode mixing, splitting ratios, and reflection and transmission probabilities.

Bortolotti, Daniele C.E.; Bohn, John L. [JILA and Department of Physics, University of Colorado, Boulder, Colorado 80309-0440 (United States)

2004-03-01T23:59:59.000Z

190

HNCO in molecular clouds  

SciTech Connect (OSTI)

In a survey of 18 molecular clouds, HNCO J/sub K/-1K1..-->..J'/sub K/'-1K'1 = 5/sub 05/..-->..4/sub 05/ and 4/sub 04/..-->..3/sub 03/ emission was etected in seven clouds, and possibly in one other. Emission in these transitions originates in high-density regions (n> or approx. =10/sup 6/ cm/sup -3/). The molecule's excitation requirements allow us to derive limits to excitation temperatures an optical depths. We discuss the possibility of clumping with respect to the beam and compare our results with data from other molecular species. The HNCO emission from Sgr A is an ordder of magnitude larger than the other detected sources as is the ratio ..delta..T +- /sub A/(HNCO 5/sub 05/..-->..4/sub 04/)/..delta..T +- /sub A/(C/sup 18/O 1..-->..0). HNCO is probably a constituent of most molecular clouds.

Jackson, J.M.; Armstrong, J.T.; Barrett, A.H.

1984-05-15T23:59:59.000Z

191

High speed x-ray beam chopper  

DOE Patents [OSTI]

A fast, economical, and compact x-ray beam chopper with a small mass and a small moment of inertia whose rotation can be synchronized and phase locked to an electronic signal from an x-ray source and be monitored by a light beam is disclosed. X-ray bursts shorter than 2.5 microseconds have been produced with a jitter time of less than 3 ns.

McPherson, Armon (Oswego, IL); Mills, Dennis M. (Naperville, IL)

2002-01-01T23:59:59.000Z

192

VUV photoionization time-of-flight mass spectrometry of flash pyrolysis of silane and disilane  

Science Journals Connector (OSTI)

Flash pyrolysis of silane, SiH4, and disilane, Si2H6, diluted in He or Ar (1%), was carried out at temperatures ranging from ?700 to ?1500 K. After a short reaction time of ?20 ?s, the initial products were isolated in a supersonic molecular beam and detected by single vacuum ultra-violet (VUV) photon (?=118or121nm) ionization time-of-flight mass spectrometry (TOFMS). Initial decomposition and reaction products, both free radical intermediates and stable species, were directly observed, which included SiH2 and Si2H4.

Steven D. Chambreau; Jingsong Zhang

2001-01-01T23:59:59.000Z

193

LANSCE beam current limiter  

SciTech Connect (OSTI)

The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the Beam Current Limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beam line below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described.

Gallegos, F.R.

1996-06-01T23:59:59.000Z

194

Power beaming providing a space power infrastructure  

SciTech Connect (OSTI)

This study, based on two levels of technology, applies the power beaming concept to four planned satellite constellations. The analysis shows that with currently available technology, power beaming can provide mass savings to constellations in orbits ranging from low earth orbit to geosynchronous orbit. Two constellations, space surveillance and tracking system and space based radar, can be supported with current technology. The other two constellations, space-based laser array and boost surveillance and tracking system, will require power and transmission system improvements before their breakeven specific mass is achieved. A doubling of SP-100 conversion efficiency from 10 to 20/% would meet or exceed breakeven for these constellations.

Bamberger, J.A.; Coomes, E.P.

1992-08-01T23:59:59.000Z

195

BEAMS3D Neutral Beam Injection Model  

SciTech Connect (OSTI)

With the advent of applied 3D fi elds in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous velocity reduction, and pitch angle scattering are modeled with the ADAS atomic physics database [1]. Benchmark calculations are presented to validate the collisionless particle orbits, neutral beam injection model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields.

Lazerson, Samuel

2014-04-14T23:59:59.000Z

196

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.

197

LBNL-45363, CBP Note 333 BEAM-BEAM SIMULATIONS FOR SEPARATED BEAMS  

E-Print Network [OSTI]

LBNL-45363, CBP Note 333 BEAM-BEAM SIMULATIONS FOR SEPARATED BEAMS Miguel A. Furman, Center for Beam Physics, LBNL, Berkeley, CA 94720 Abstract We present beam-beam simulation results from a strong- strong gaussian code for separated beams for the LHC and RHIC. The frequency spectrum produced

Furman, Miguel

198

LBNL-46223, CBP Note 350 BEAM-BEAM SIMULATIONS FOR SEPARATED BEAMS IN THE LHC  

E-Print Network [OSTI]

LBNL-46223, CBP Note 350 BEAM-BEAM SIMULATIONS FOR SEPARATED BEAMS IN THE LHC M. A. Furman, W. C. Turner, Center for Beam Physics, LBNL, Berkeley, CA 94720, USA Abstract We present beam-beam simulation results from a strong- strong gaussian code for separated beams for the LHC. We focus on the possible

Furman, Miguel

199

BEAMS: Curiosity | Jefferson Lab  

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

BEAMS: Curiosity January 9, 2013 BEAMS, Becoming Excited About Math and Science, is one of our education programs. In particular, it is the only one in which I participate with...

200

Mass spectrometry: analytical capabilities and potentials  

Science Journals Connector (OSTI)

...INSULIN AND OTHER LARGE PEPTIDES, JOURNAL...MASS-SPECTROMETRY OF LARGE, FRAGILE, AND INVOLATILE...APPLICATIONS IN THE AREA OF MOLECULAR MODIFICATIONS...I-127-LABELED PLASMA DESORPTION MASS-SPECTROMETRY...PIONEER VENUS LARGE PROBE NEUTRAL MASS-SPECTROMETER...HORNING, E.C., ATMOSPHERIC-PRESSURE IONIZATION...

RG Cooks; KL Busch; GL Glish

1983-10-21T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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.


201

Molecular Foundry  

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

The Molecular Foundry The Molecular Foundry Lawrence Berkeley National Laboratory One Cyclotron Road Building 67 Berkeley, CA 94720 Screen reader users: click here for plain HTML Go to Google Maps Home Molecular Foundry, Berkeley, CA Loading... Map Sat Ter Did you mean a different: Did you mean a different: Did you mean a different: Add Destination - Show options Hide options Get Directions Note: Public transit coverage may not be available in this area. Molecular Foundry, Berkeley, CA A Molecular Foundry 67 Cyclotron Rd, Berkeley, CA ‎ foundry.lbl.gov 3 reviews · "Berkeley Lab. About the Foundry. What is the Molecular Foundry? Research Themes; Foundry Careers; Media Gallery; Other User Facilities external link; Contact Us" - lbl.gov Directions Search nearby more See all 14 results for Molecular Foundry, Berkeley, CA

202

In situ secondary ion mass spectrometry analysis. 1992 Summary report  

SciTech Connect (OSTI)

The direct detection of tributyl phosphate (TBP) on rocks using molecular beam surface analysis [MBSA or in situ secondary ion mass spectrometry (SIMS)] is demonstrated. Quantities as low as 250 ng were detected on basalt and sandstone with little or no sample preparation. Detection of TBP on soil has proven to be more problematic and requires further study. Ethylenediaminetetraacetic acid (EDTA) is more difficult to detect because it is very reactive with surfaces of interest. Nevertheless, it is possible to detect EDTA if the acidity of the surface is controlled. The detection of EDTA-metal complexes is currently an open question, but evidence is presented for the detection of ions arising from a EDTA-lead complex. Carboxylic acids (i.e., citric, ascorbic, malic, succinic, malonic, and oxalic) give characteristic SIM spectra, but their detection on sample surfaces awaits evaluation.

Groenewold, G.S.; Applehans, A.D.; Ingram, J.C.; Delmore, J.E.; Dahl, D.A.

1993-01-01T23:59:59.000Z

203

2012 MOLECULAR AND IONIC CLUSTERS GORDON RESEARCH CONFERENCE, JANUARY 29 - FEBRUARY 3, 2012  

SciTech Connect (OSTI)

The Gordon Research Conference on 'Molecular and Ionic Clusters' focuses on clusters, which are the initial molecular species found in gases when condensation begins to occur. Condensation can take place solely from molecules interacting with each other, mostly at low temperatures, or when molecules condense around charged particles (electrons, protons, metal cations, molecular ions), producing ion molecule clusters. These clusters provide models for solvation, allow a pristine look at geometric as well as electronic structures of molecular complexes or matter in general, their interaction with radiation, their reactivity, their thermodynamic properties and, in particular, the related dynamics. This conference focuses on new ways to make clusters composed of different kinds of molecules, new experimental techniques to investigate the properties of the clusters and new theoretical methods with which to calculate the structures, dynamical motions and energetics of the clusters. Some of the main experimental methods employed include molecular beams, mass spectrometry, laser spectroscopy (from infrared to XUV; in the frequency as well as the time domain) and photoelectron spectroscopy. Techniques include laser absorption spectroscopy, laser induced fluorescence, resonance enhanced photoionization, mass-selected photodissociation, photofragment imaging, ZEKE photoelectron spectroscopy, etc. From the theoretical side, this conference highlights work on potential surfaces and measurable properties of the clusters. The close ties between experiment, theory and computation have been a hallmark of the Gordon Research Conference on Molecular and Ionic Clusters. In the 2012 meeting, we plan to have sessions that will focus on topics including: (1) The use of cluster studies to probe fundamental phenomena; (2) Finite size effects on structure and thermodynamics; (3) Intermolecular forces and cooperative effects; (4) Molecular clusters as models for solvation; and (5) Studies of clusters at XUV light sources.

Anne McCoy

2012-02-03T23:59:59.000Z

204

Ion Beams - Radiation Effects Facility / Cyclotron Institute...  

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

Ion Beams Available Beams Beam Change Times Measurements Useful Graphs Various ion beams have been developed specifically for the Radiation Effects Facility. These beams...

205

ATA beam director experiment  

SciTech Connect (OSTI)

This report describes beam director elements for an experiment at the Advanced Test Accelerator. The elements described include a vernier magnet for beam aiming, an achromat magnet, and an isolation system for the beam interface. These components are built at small scale for concept testing. (JDH)

Lee, E.P.; Younger, F.C.; Cruz, G.E.; Nolting, E.

1986-06-23T23:59:59.000Z

206

Inexpensive dual beam turbidimeter  

Science Journals Connector (OSTI)

...Articles Articles Inexpensive dual beam turbidimeter Cathie Lubell Thomas Barry Edward Brody Gregory Hearn This dual beam turbidimeter...74D728B5-2B21-11D7-8648000102C1865D Inexpensive dual beam turbidimeter Lubell Cathie Author Barry Thomas Author Brody Edward Author Hearn...

Cathie Lubell; Thomas Barry; Edward Brody; Gregory Hearn

207

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

208

Born-Oppenheimer approximation for mass scaling of cold-collision properties  

SciTech Connect (OSTI)

Asymptotic levels of the A {sup 1}{sigma}{sub u}{sup +} state of the two isotopomers {sup 39}K{sub 2} and {sup 39}K{sup 41}K up to the dissociation limit are investigated with a Doppler-free high resolution laser-spectroscopic experiment in a molecular beam. The observed level structure can be reproduced correctly only if a mass dependent correction term is introduced for the interaction potential. The applied relative correction in the depth of the potential is 10{sup -6}, which is in the order of magnitude expected for corrections of the Born-Oppenheimer approximation. A similar change in ground state potentials might lead to significant changes of mass-scaled properties describing cold collisions like the s-wave scattering length.

Falke, Stephan; Tiemann, Eberhard; Lisdat, Christian [Institut fuer Quantenoptik, Leibniz Universitaet Hannover, Welfengarten 1, 30167 Hannover (Germany)

2007-07-15T23:59:59.000Z

209

Beam-Gas  

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

Gas Gas and Thermal Photon Scattering in the NLC Main Linac as a Source of Beam Halo P. Tenenbaum LCC-Note-0051 12-JAN-2001 Abstract Scattering of primary beam electrons off of residual gas molecules or blackbody radiation photons in the NLC main linac has been identified as a potential source of beam haloes which must be collimated in the beam delivery system. We consider the contributions from four scat- tering mechanisms: inelastic thermal-photon scattering, elastic beam-gas (Coulomb) scattering inelastic beam-gas (Bremsstrahlung) scattering, and atomic-electron scattering. In each case we develop the formalism necessary to estimate the backgrounds generated in the main linac, and determine the expected number of off-energy or large-amplitude particles from each process, assuming a main linac injection energy of 8 GeV and extraction energy of 500 GeV. 1 Introduction The

210

Ion Beam Materials Lab  

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

Facilities » Facilities » Ion Beam Materials Lab Ion Beam Materials Lab A new research frontier awaits! Our door is open and we thrive on mutually beneficial partnerships, collaborations that drive innovations and new technologies. April 12, 2012 Ion Beam Danfysik Implanter High Voltage Terminal. Contact Yongqiang Wang (505) 665-1596 Email Devoted to the characterization and modification of surfaces through the use of ion beams The Ion Beam Materials Laboratory (IBML) is a Los Alamos National Laboratory resource devoted to the characterization and modification of surfaces through the use of ion beams. The IBML provides and operates the core facilities, while supporting the design and implementation of specific apparati needed for experiments requested by users of the facility. The result is a facility with

211

Noninterceptive beam diagnostics  

SciTech Connect (OSTI)

The need for accurate real-time diagnostics is critical for high-power particle beams. This paper describes the present level of development of noninterceptive devices for these beams. Discussion will be related to diagnostic measurements as they occur along the beamline, from ion-source performance through presentation to an RFQ and measures of the RFQ output, using the cw beam at Los Alamos as a guide. 23 refs.

Chamberlin, D.D.

1985-01-01T23:59:59.000Z

212

Kicked surface muon beams  

Science Journals Connector (OSTI)

The possibility of splitting a surface muon beam into three separate components using an ... and could be very effectively used to provide muons to time differential ?SR experiments.

J. L. Beveridge

1992-01-01T23:59:59.000Z

213

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

214

Pyrolysis of Organic Molecules Relevant to Combustion as Monitored by Photoionization Time-of-Flight Mass Spectrometry  

E-Print Network [OSTI]

of Small Molecules by Flash Pyrolysis, University ofapproach of coupling flash pyrolysis of the compound ofZhang, Chairperson Flash pyrolysis coupled to molecular beam

Weber, Kevin Howard

2010-01-01T23:59:59.000Z

215

Piezoelectric energy harvester having planform-tapered interdigitated beams  

DOE Patents [OSTI]

Embodiments of energy harvesters have a plurality of piezoelectric planform-tapered, interdigitated cantilevered beams anchored to a common frame. The plurality of beams can be arranged as two or more sets of beams with each set sharing a common sense mass affixed to their free ends. Each set thus defined being capable of motion independent of any other set of beams. Each beam can comprise a unimorph or bimorph piezoelectric configuration bonded to a conductive or non-conductive supporting layer and provided with electrical contacts to the active piezoelectric elements for collecting strain induced charge (i.e. energy). The beams are planform tapered along the entirety or a portion of their length thereby increasing the effective stress level and power output of each piezoelectric element, and are interdigitated by sets to increase the power output per unit volume of a harvester thus produced.

Kellogg, Rick A. (Tijeras, NM); Sumali, Hartono (Albuquerque, NM)

2011-05-24T23:59:59.000Z

216

The mass  

Science Journals Connector (OSTI)

The mass of the charged Higgs boson at the 1-loop level is investigated, assuming the CP symmetry to be violated explicitly in the Higgs sector of the minimal supersymmetric standard model (MSSM). It is found that there is a parameter region of the MSSM where the presence of explicit CP violation in the Higgs sector yields negative radiative corrections to the charged Higgs boson mass. Thus, the charged Higgs boson in the MSSM may have as low a mass as 60GeV at the 1-loop level, if the CP symmetry is violated. This lower bound may be improved by the Higgs search at LEP2, which imposes experimental constraints on the charged Higgs mass, as well as on the masses of the neutral Higgs bosons. Hence, LEP2 can constrain experimentally the charged Higgs mass to be not smaller than 109GeV under our assumption. In addition, it sets 75GeV as the lower bound on the mass of the lightest neutral Higgs boson, and 84GeV for that of the next-to-lightest neutral Higgs boson.

Seung Woo Ham; Sun Kun Oh; Eun Jong Yoo; Hyun Kyu Lee

2001-01-01T23:59:59.000Z

217

Molecular biochemistry  

Science Journals Connector (OSTI)

... THIS text forms a very readable handbook which outlines the ... which outlines the fundamentals of electrostatic and dielectric theory on the one hand and of chemical bonding and molecular ...

B. Jennings

1978-09-07T23:59:59.000Z

218

Beam director design report  

SciTech Connect (OSTI)

A design and fabrication effort for a beam director is documented. The conceptual design provides for the beam to pass first through a bending and focusing system (or ''achromat''), through a second achromat, through an air-to-vacuum interface (the ''beam window''), and finally through the vernier steering system. Following an initial concept study for a beam director, a prototype permanent magnet 30/sup 0/ beam-bending achromat and prototype vernier steering magnet were designed and built. In volume II, copies are included of the funding instruments, requests for quotations, purchase orders, a complete set of as-built drawings, magnetic measurement reports, the concept design report, and the final report on the design and fabrication project. (LEW)

Younger, F.C.

1986-08-01T23:59:59.000Z

219

Penning trap mass measurements on nobelium isotopes  

SciTech Connect (OSTI)

The Penning trap mass spectrometer SHIPTRAP at GSI Darmstadt allows accurate mass measurements of radionuclides, produced in fusion-evaporation reactions and separated by the velocity filter SHIP from the primary beam. Recently, the masses of the three nobelium isotopes {sup 252-254}No were determined. These are the first direct mass measurements of transuranium elements, which provide new anchor points in this region. The heavy nuclides were produced in cold-fusion reactions by irradiating a PbS target with a {sup 48}Ca beam, resulting in production rates of the nuclei of interest of about one atom per second. In combination with data from decay spectroscopy our results are used to perform a new atomic-mass evaluation in this region.

Dworschak, M.; Block, M.; Ackermann, D.; Herfurth, F.; Hessberger, F. P.; Hofmann, S.; Vorobyev, G. K. [GSI Helmholtzzentrum fuer Schwerionenforschung, D-64291 Darmstadt (Germany); Audi, G. [CSNSM-IN2P3-CNRS, F-91405 Orsay-Campus (France); Blaum, K. [Max-Planck-Institut fuer Kernphysik, D-69117 Heidelberg (Germany); Ruprecht-Karls-Universitaet, D-69120 Heidelberg (Germany); Droese, C.; Marx, G.; Schweikhard, L. [Ernst-Moritz-Arndt-Universitaet, Institut fuer Physik, D-17487 Greifswald (Germany); Eliseev, S.; Ketter, J. [Max-Planck-Institut fuer Kernphysik, D-69117 Heidelberg (Germany); Fleckenstein, T. [Justus-Liebig-Universitaet Giessen, D-35390 Giessen (Germany); Haettner, E.; Plass, W. R.; Scheidenberger, C. [GSI Helmholtzzentrum fuer Schwerionenforschung, D-64291 Darmstadt (Germany); Justus-Liebig-Universitaet Giessen, D-35390 Giessen (Germany); Ketelaer, J. [Johannes Gutenberg-Universitaet, Institut fuer Physik, D-55099 Mainz (Germany); Kluge, H.-J. [GSI Helmholtzzentrum fuer Schwerionenforschung, D-64291 Darmstadt (Germany); Ruprecht-Karls-Universitaet, D-69120 Heidelberg (Germany)

2010-06-15T23:59:59.000Z

220

Noise reduction in negative-ion quadrupole mass spectrometry  

DOE Patents [OSTI]

A quadrupole mass spectrometer (QMS) system having an ion source, quadrupole mass filter, and ion collector/recorder system. A weak, transverse magnetic field and an electron collector are disposed between the quadrupole and ion collector. When operated in negative ion mode, the ion source produces a beam of primarily negatively-charged particles from a sample, including electrons as well as ions. The beam passes through the quadrupole and enters the magnetic field, where the electrons are deflected away from the beam path to the electron collector. The negative ions pass undeflected to the ion collector where they are detected and recorded as a mass spectrum.

Chastagner, Philippe (3134 Natalie Cir., Augusta, GA 30909-2748)

1993-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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

Measurements - Ion Beams - Radiation Effects Facility / Cyclotron...  

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

Ion Beams Available Beams Beam Change Times Measurements Useful Graphs Measurements The beam uniformity and flux are determined using an array of five detectors. Each...

222

E-Print Network 3.0 - analytical mass spectrometry Sample Search...  

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

of cluster primary ion beams for applications in secondary ion mass spectrometry (SIMS), motivated... surface analysis, microscopy, ion solid interactions, biological and...

223

E-Print Network 3.0 - atomic mass spectrometry Sample Search...  

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

of cluster primary ion beams for applications in secondary ion mass spectrometry (SIMS), motivated... surface analysis, microscopy, ion solid interactions, biological and...

224

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

225

Intense proton beam source for ITER neutral-beam spectroscopy diagnostics  

SciTech Connect (OSTI)

An intense proton beam has been developed to evaluate a gas-cell neutralizer for use in an intense-neutral beam source for Tokomak Spectroscopy diagnostics. The allowed energy range of the proton stream is determined to be 50 to 70 keV from neutralization and reionization cross-sections and from the alpha particle charge exchange recombination intensity as a function of energy (baseline diagnostic). The neutralization evaluation source uses a flashover anode, magnetized, ion-diode. Neutral probes sensitive to energetic atomic and molecular hydrogen, developed to evaluate neutralizer performance, show neutral fluence from the ion-diode during the beam pulse. An array of Rogowski current probes, used to study the evolution of the current path, suggests that expansion of the anode plasma along the radial insulating magnetic field leads to impedance collapse.

Bartsch, R.R.; Davis, H.A.; Henins, I. [Los Alamos National Lab., NM (United States); Greenly, J.B. [Cornell Univ., Ithaca, NY (United States)

1994-09-01T23:59:59.000Z

226

Challenges in Accelerator Beam Instrumentation  

SciTech Connect (OSTI)

The challenges in beam instrumentation and diagnostics for present and future particle accelerator projects are presented. A few examples for advanced hadron and lepton beam diagnostics are given.

Wendt, M.

2009-12-01T23:59:59.000Z

227

Beta-beams  

E-Print Network [OSTI]

Beta-beams is a new concept for the production of intense and pure neutrino beams. It is at the basis of a proposed neutrino facility, whose main goal is to explore the possible existence of CP violation in the lepton sector. Here we briefly review the original scenario and the low energy beta-beam. This option would offer a unique opportunity to perform neutrino interaction studies of interest for particle physics, astrophysics and nuclear physics. Other proposed scenarios for the search of CP violation are mentioned.

C. Volpe

2008-02-22T23:59:59.000Z

228

TOF-SIMS/MALDI-TOF combination for the molecular weight depth profiling of polymeric bilayer  

Science Journals Connector (OSTI)

Abstract A polymeric bilayer composed of two poly(styrene) layers differing by their molecular weights (MW) was elaborated to mimic a MW gradient and analyzed by a combination of TOF-SIMS, MALDI-MS and Nanoscratch (NS). A direct TOF-SIMS profiling conducted using a Cs+ ion beam lead to the detection of fragments from carbonated layers without any data about their MW, making the fine bilayer architecture indistinguishable. Spots of various depths were hence created using the same Cs+ ion bombardment for different sputtering times, and further mass-analyzed by the recently developed Surface-Layer MALDI-MS technique, to evaluate the MW of the very top polymeric layer of each crater. The off-line combination of ion etching and LASER analysis allowed a molecular weight depth profile to be plotted, as a function of the physical depth measured by NS in each crater (instead of the usual sputter time). This original coupling is expected to provide useful molecular and/or molecular weight data about complex organic and/or polymeric multi-layers or gradients.

Thierry Fouquet; Grgory Mertz; Nicolas Desbenoit; Gilles Frache; David Ruch

2014-01-01T23:59:59.000Z

229

Molecular Foundry  

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

Berkeley Lab Berkeley Lab A-Z Index Phone Book Jobs Search DOE Berkeley Lab Berkeley Lab A-Z Index Phone Book Jobs Search DOE About the Foundry What is the Molecular Foundry? Research Themes Foundry Careers Media Gallery Other User Facilities external link Contact Us Go News & Highlights Users People Facilities Imaging and Manipulation Nanofabrication Theory Inorganic Biological Organic NCEM external link Seminars & Events Publications The Molecular Foundry is a Department of Energy-funded nanoscience research facility that provides users from around the world with access to cutting-edge expertise and instrumentation in a collaborative, multidisciplinary environment. Call for Proposals: The next deadline for standard proposals is Through March 31, 2014 Find out more information about becoming a Molecular Foundry facilities User. 2013 Annual User Meeting Postponed - Date TBD

230

Inverse time-of-flight spectrometer for beam plasma research  

Science Journals Connector (OSTI)

The paper describes the design and principle of operation of an inverse time-of-flight spectrometer for research in the plasma produced by an electron beam in the forevacuum pressure range (520 Pa). In the spectrometer the deflecting plates as well as the drift tube and the primary ion beam measuring system are at high potential with respect to ground. This provides the possibility to measure the mass-charge constitution of the plasma created by a continuous electron beam with a current of up to 300 mA and electron energy of up to 20 keV at forevacuum pressures in the chamber placed at ground potential. Research results on the mass-charge state of the beam plasma are presented and analyzed.

A. V. Tyunkov; K. P. Savkin

2014-01-01T23:59:59.000Z

231

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

232

Courses on Beam Physics  

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

Beam Physics Beam Physics The following is an incomplete listing of course available for beam physics. United States Particle Accelerator School The US Particle Accelerator School provides educational programs in the field of beams and their associated accelerator technologies not otherwise available to the community of science and technology. Joint Universities Accelerator School Each year JUAS provides a foundation course on accelerator physics and associated technologies. The US-CERN-Japan-Russia Joint Accelerator School The purpose of the US-CERN-Japan-Russia joint school is to better our relations by working together on an advanced topical course every two years, alternating between the U.S., western Europe, Japan and Russia. The last set of courses focused on the frontiers of accelerator technology in

233

Focused ion beam system  

DOE Patents [OSTI]

A focused ion beam (FIB) system produces a final beam spot size down to 0.1 {mu}m or less and an ion beam output current on the order of microamps. The FIB system increases ion source brightness by properly configuring the first (plasma) and second (extraction) electrodes. The first electrode is configured to have a high aperture diameter to electrode thickness aspect ratio. Additional accelerator and focusing electrodes are used to produce the final beam. As few as five electrodes can be used, providing a very compact FIB system with a length down to only 20 mm. Multibeamlet arrangements with a single ion source can be produced to increase throughput. The FIB system can be used for nanolithography and doping applications for fabrication of semiconductor devices with minimum feature sizes of 0.1 m or less. 13 figs.

Leung, K.; Gough, R.A.; Ji, Q.; Lee, Y.Y.

1999-08-31T23:59:59.000Z

234

BNL | ATF Beam Diagnostics  

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

Beamline Spectrometry Both ATF beam lines have dipoles, which serve as spectrometers, the vacuum chambers on of these dipoles also have zero degree ports that may be covered with a...

235

Electron Beam Ion Sources  

E-Print Network [OSTI]

Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviolet, visible light) from highly charged ions. This chapter gives an overview of EBIS physics, the principle of operation, and the known technical solutions. Using examples, the performance of EBISs as well as their applications in various fields of basic research, technology and medicine are discussed.

Zschornacka, G; Thorn, A

2013-01-01T23:59:59.000Z

236

BNL | ATF Beam Schedule  

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

Beam Schedule (pdf) Beam Schedule (pdf) Sunday Monday Tuesday Wednesday Thursday Friday Saturday 22 1/2 Holiday Holiday 28 January Holiday 4 5 Maintenance 11 12 Maintenance 18 19 Holiday AE52 - DWFA (Euclid), BL2 25 February AE52 - DWFA (Euclid), BL2 1 2 AE50 - PWFA in QNR (UCLA), BL2 8 9 AE50 - PWFA in QNR (UCLA), BL2 15 16 Holiday AE50 - PWFA in QNR (UCLA), BL2 22 March 1 2 AE53 - Nonlinear Compton (UCLA) 8 9 AE53 - Nonlinear Compton (UCLA) 15 16 AE53 - Nonlinear Compton (UCLA) 22 23 29 Sunday Monday Tuesday Wednesday Thursday Friday Saturday User operations (E-beam in use) Ions - Ion generation User operations (laser in use) PWFA - Plasma Wakefield Acceleration User operations (E-beam and laser in use)

237

Molecular Gas Reservoir in low-z Powerful Radio Galaxies  

E-Print Network [OSTI]

We report a survey for molecular gas in 3C radio galaxies at redshifts z gas masses in the range 10^7--10^9 Msun. The remainder had typical upper limits in molecular gas masses of ~10^8 Msun.

Jeremy Lim; Stephane Leon; Francoise Combes; Dinh-V-Trung

2002-11-13T23:59:59.000Z

238

Small Spot, Brighter Beam  

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

Small Spot, Brighter Beam Small Spot, Brighter Beam Small Spot, Brighter Beam Print Do you notice the brighter beam? During the most recent shutdown, all of the corrector magnets were replaced with sextupoles, reducing the horizontal emittance and increasing beam brightness. "This is part of ongoing improvement to keep the ALS on the cutting edge," says Alastair MacDowell, a beamline scientist on Beamline 12.2.2. The brightness has increased by a factor of about three in the storage ring. Beamlines on superbend or center-bend magnets will see the most noticeable increase in brightness, but the horizontal beam size and divergence have been substantially reduced at all beamlines. "We are starting to approach the resolution of many beamlines. Therefore, not every beamline will be able to resolve the full improvement," says Christoph Steier, project leader of the brightness upgrade. Though superbend and center-bend magnet source sizes are reduced by roughly a factor of three, "measured improvements so far range from a factor of 2-2.5," Steier says. He and MacDowell agree that the beamline optics are likely the limiting factor in resolving the full improvement at the beamlines.

239

Ion-beam superpinch  

Science Journals Connector (OSTI)

Intense nonrelativistic light-ion beams generated in magnetically insulated diodes can reach total beam currents large enough to confine charged fusion products within pinch channels which are formed by these beams if they are projected onto thermonuclear material. Furthermore, since the required beam currents are still below the critical Alfvn current, these pinch channels are magnetohydrodynamically stable. However, because the time these beams last is very short and of the order of 10 nsec, the thermonuclear target must have a density at least as large as solid-state density to satisfy the Lawson criterion. This large target density makes it necessary that the beam be focused down to a radius less than ? 10-2 cm, to balance the plasma pressure against the magnetic pressure. To make this focusing possible a new kind of a low-emittance intense ion source is proposed. It consists of pointlike pulsed dense plasma positioned in the field-free space behind a meshlike anode. The focusing itself can be done in three steps, first by sufficiently good ion optics, second by wall focusing, and third by radiation cooling. This inertial-confinement fusion concept avoids the problems of reaching this goal through highdensity target compression by ablative implosion.

F. Winterberg

1981-10-01T23:59:59.000Z

240

Wire Scanner Beam Profile Measurements: LANSCE Facility Beam Development  

SciTech Connect (OSTI)

The Los Alamos Neutron Science Center (LANSCE) is replacing Wire Scanner (WS) beam profile measurement systems. Three beam development tests have taken place to test the new wire scanners under beam conditions. These beam development tests have integrated the WS actuator, cable plant, electronics processors and associated software and have used H{sup -} beams of different beam energy and current conditions. In addition, the WS measurement-system beam tests verified actuator control systems for minimum profile bin repeatability and speed, checked for actuator backlash and positional stability, tested the replacement of simple broadband potentiometers with narrow band resolvers, and tested resolver use with National Instruments Compact Reconfigurable Input and Output (cRIO) Virtual Instrumentation. These beam tests also have verified how trans-impedance amplifiers react with various types of beam line background noise and how noise currents were not generated. This paper will describe these beam development tests and show some resulting data.

Gilpatrick, John D. [Los Alamos National Laboratory; Batygin, Yuri K. [Los Alamos National Laboratory; Gonzales, Fermin [Los Alamos National Laboratory; Gruchalla, Michael E. [Los Alamos National Laboratory; Kutac, Vincent G. [Los Alamos National Laboratory; Martinez, Derwin [Los Alamos National Laboratory; Sedillo, James Daniel [Los Alamos National Laboratory; Pillai, Chandra [Los Alamos National Laboratory; Rodriguez Esparza, Sergio [Los Alamos National Laboratory; Smith, Brian G. [Los Alamos National Laboratory

2012-05-15T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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

Single element laser beam shaper  

DOE Patents [OSTI]

A single lens laser beam shaper for converting laser beams from any spatial profile to a flat-top or uniform spatial profile. The laser beam shaper includes a lens having two aspheric surfaces. The beam shaper significantly simplifies the overall structure in comparison with conventional 2-element systems and therefore provides great ease in alignment and reduction of cost.

Zhang, Shukui (Yorktown, VA); Michelle D. Shinn (Newport News, VA)

2005-09-13T23:59:59.000Z

242

Supercritical Helium Cooling of the LHC Beam Screens  

E-Print Network [OSTI]

The cold mass of the LHC superconducting magnets, operating in pressurised superfluid helium at 1.9 K, must be shielded from the dynamic heat loads induced by the circulating particle beams, by means of beam screens maintained at higher temperature. The beam screens are cooled between 5 and 20 K by forced flow of weakly supercritical helium, a solution which avoids two-phase flow in the long, narr ow cooling channels, but still presents a potential risk of thermohydraulic instabilities. This problem has been studied by theoretical modelling and experiments performed on a full-scale dedicated te st loop.

Hatchadourian, E; Tavian, L

1998-01-01T23:59:59.000Z

243

Molecular nanostructure and nanotechnology  

Science Journals Connector (OSTI)

...Molecular nanostructure and nanotechnology compiled and edited by Chunli...Molecular nanostructure and nanotechnology Chunli Bai 1 Chen Wang 2...Molecular nanostructure and nanotechnology . This Theme Issue exemplifies...

2013-01-01T23:59:59.000Z

244

Light beam frequency comb generator  

DOE Patents [OSTI]

A light beam frequency comb generator uses an acousto-optic modulator to generate a plurality of light beams with frequencies which are uniformly separated and possess common noise and drift characteristics. A well collimated monochromatic input light beam is passed through this modulator to produce a set of both frequency shifted and unshifted optical beams. An optical system directs one or more frequency shifted beams along a path which is parallel to the path of the input light beam such that the frequency shifted beams are made incident on the modulator proximate to but separated from the point of incidence of the input light beam. After the beam is thus returned to and passed through the modulator repeatedly, a plurality of mutually parallel beams are generated which are frequency-shifted different numbers of times and possess common noise and drift characteristics.

Priatko, Gordon J. (Cupertino, CA); Kaskey, Jeffrey A. (Livermore, CA)

1992-01-01T23:59:59.000Z

245

The molecular structure of PrI3 and GdI3 as determined by synchronous gas-phase electron diffraction and mass spectrometric experiment assisted by quantum chemical calculations  

Science Journals Connector (OSTI)

A gas electron diffraction study of PrI3 and GdI3 has been carried out in combination with mass spectrometric vapour monitoring at 1110(10)K and 1100(10)K, respectively. Up to 3mol.% of dimeric species was obs...

Nina I. Giricheva; Sergey A. Shlykov; Elena A. Lapykina

2011-04-01T23:59:59.000Z

246

Mass-Independent Isotope Effects  

Science Journals Connector (OSTI)

Scientific interests: ESR and NMR spectroscopies, molecular magnets, mechanisms of chemical and biochemical reactions, spin physics and chemistry, isotopes and isotope effects in chemistry and biochemistry. ... Another mass-independent isotope effect was detected in 1983 as a deviation of isotopic distribution in reaction products from that which would be expected from the mass-dependent isotope effect. ... Later, Nomura et al.(92) have found isotopic 233U anomaly in the U4+U6+ exchange reaction; they noted that the isotope effect was correlated with isotope shifts in the atomic spectra of uranium isotopes. ...

Anatoly L. Buchachenko

2013-01-09T23:59:59.000Z

247

SLC beam dynamics issues  

SciTech Connect (OSTI)

The Stanford Linear Collider (SLC){sup 1,2} accelerates single bunches of electrons and positrons to 47 GeV per beam and collides them with small beam sizes and at high currents. The beam emittances and intensities required for present operation have significantly extended traditional beam quality limits. The electron source produces over 10{sup 11} e{sup {minus}} in each of two bunches. The damping rings provide coupled invariant emittances of 1.8 {times} 10{sup {minus}5} r-m at 4.5 {times} 10{sup 10} particles. The 50 GeV linac has successfully accelerated over 3 {times} 10{sup 10} particles with design invariant emittances of 3 {times} 10{sup {minus}5} r-m. The collider arcs are now sufficiently decoupled and matched in betatron space, so that the final focus can be chromatically corrected, routinely producing spot sizes ({sigma}{sub x}, {sigma}{sub y}) of 2.5 {mu}m at the interaction point. Spot sizes below 2 {mu}m have been made during tests. Instrumentation and feedback systems are well advanced, providing continuous beam monitoring and considerable pulse-by-pulse control. The luminosity reliability is about 60%. Overviews of the recent accelerator physics achievements used to obtain these parameters and the present limiting phenomena are described for each accelerator subsystem.

Seeman, J.T.

1991-12-01T23:59:59.000Z

248

Low interfacial trap density and sub-nm equivalent oxide thickness in In{sub 0.53}Ga{sub 0.47}As (001) metal-oxide-semiconductor devices using molecular beam deposited HfO{sub 2}/Al{sub 2}O{sub 3} as gate dielectrics  

SciTech Connect (OSTI)

We investigated the passivation of In{sub 0.53}Ga{sub 0.47}As (001) surface by molecular beam epitaxy techniques. After growth of strained In{sub 0.53}Ga{sub 0.47}As on InP (001) substrate, HfO{sub 2}/Al{sub 2}O{sub 3} high-{kappa} oxide stacks have been deposited in-situ after surface reconstruction engineering. Excellent capacitance-voltage characteristics have been demonstrated along with low gate leakage currents. The interfacial density of states (D{sub it}) of the Al{sub 2}O{sub 3}/In{sub 0.53}Ga{sub 0.47}As interface have been revealed by conductance measurement, indicating a downward D{sub it} profile from the energy close to the valence band (medium 10{sup 12} cm{sup -2}eV{sup -1}) towards that close to the conduction band (10{sup 11} cm{sup -2}eV{sup -1}). The low D{sub it}'s are in good agreement with the high Fermi-level movement efficiency of greater than 80%. Moreover, excellent scalability of the HfO{sub 2} has been demonstrated as evidenced by the good dependence of capacitance oxide thickness on the HfO{sub 2} thickness (dielectric constant of HfO{sub 2}{approx}20) and the remained low D{sub it}'s due to the thin Al{sub 2}O{sub 3} passivation layer. The sample with HfO{sub 2} (3.4 nm)/Al{sub 2}O{sub 3} (1.2 nm) as the gate dielectrics has exhibited an equivalent oxide thickness of {approx}0.93 nm.

Chu, L. K. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Katholieke Universiteit Leuven, 3001 Leuven (Belgium); Merckling, C.; Dekoster, J.; Caymax, M. [Interuniversity Microelectronics Center (IMEC vzw), 3001 Leuven (Belgium); Alian, A.; Heyns, M. [Katholieke Universiteit Leuven, 3001 Leuven (Belgium); Interuniversity Microelectronics Center (IMEC vzw), 3001 Leuven (Belgium); Kwo, J. [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan (China); Hong, M. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

2011-07-25T23:59:59.000Z

249

Beam Profile Monitor With Accurate Horizontal And Vertical Beam Profiles  

DOE Patents [OSTI]

A widely used scanner device that rotates a single helically shaped wire probe in and out of a particle beam at different beamline positions to give a pair of mutually perpendicular beam profiles is modified by the addition of a second wire probe. As a result, a pair of mutually perpendicular beam profiles is obtained at a first beamline position, and a second pair of mutually perpendicular beam profiles is obtained at a second beamline position. The simple modification not only provides more accurate beam profiles, but also provides a measurement of the beam divergence and quality in a single compact device.

Havener, Charles C [Knoxville, TN; Al-Rejoub, Riad [Oak Ridge, TN

2005-12-26T23:59:59.000Z

250

Beam-Based Alignment  

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

One: One: Single-Bunch Comparative Study of Three Algorithms Peter Tenenbaum LCC-Note-0013 17-February-1999 Abstract We describe the results of a series of simulation studies of beam-based alignment of the NLC main linacs using the program LIAR. Three algorithms for alignment of quadrupoles and girders are consid- ered: the algorithm used in the ZDR, the ZDR algorithm combined with a post-alignment MICADO operation, and an algorithm which requires no steering dipoles but requires twice as many alignment segments per linac as the ZDR algorithm. The third algorithm appears to be the most robust, based on convergence time, required quad mover step sizes, and variation in extracted beam emittance as a function of BNS profile. We also study the effect of structure BPM resolution and ATL misalignments during the alignment process. 1 Introduction Beam-based alignment and steering of the

251

Fundamental Vibration of Molecular Hydrogen  

Science Journals Connector (OSTI)

The fundamental ground tone vibration of H2, HD, and D2 is determined to an accuracy of 210-4??cm-1 from Doppler-free laser spectroscopy in the collisionless environment of a molecular beam. This rotationless vibrational splitting is derived from the combination difference between electronic excitation from the X1?g+, v=0, and v=1 levels to a common EF1?g+, v=0 level. Agreement within 1? between the experimental result and a full abinitio calculation provides a stringent test of quantum electrodynamics in a chemically bound system.

G. D. Dickenson; M. L. Niu; E. J. Salumbides; J. Komasa; K. S. E. Eikema; K. Pachucki; W. Ubachs

2013-05-08T23:59:59.000Z

252

Evaluation and Compensation of Detector Solenoid Effects on Disrupted Beam in the ILC 14 mrad Extraction Line  

SciTech Connect (OSTI)

This paper presents calculations of detector solenoid effects on disrupted primary beam in the ILC 14 mrad extraction line. Particle tracking simulations are performed for evaluation of primary beam loss along the line as well as of beam distribution and polarization at Compton Interaction Point. The calculations are done both without and with solenoid compensation. The results are obtained for the baseline ILC energy of 500 GeV center-of-mass and three options of beam parameters.

Toprek, Dragan; /VINCA Inst. Nucl. Sci., Belgrade; Nosochkov, Yuri; /SLAC

2008-12-18T23:59:59.000Z

253

Non-Paraxial Accelerating Beams  

E-Print Network [OSTI]

We present the spatially accelerating solutions of the Maxwell equations. Such non-paraxial beams accelerate in a circular trajectory, thus generalizing the concept of Airy beams. For both TE and TM polarizations, the beams exhibit shape-preserving bending with sub-wavelength features, and the Poynting vector of the main lobe displays a turn of more than 90 degrees. We show that these accelerating beams are self-healing, analyze their properties, and compare to the paraxial Airy beams. Finally, we present the new family of periodic accelerating beams which can be constructed from our solutions.

Ido Kaminer; Rivka Bekenstein; Jonathan Nemirovsky; Mordechai Segev

2012-02-03T23:59:59.000Z

254

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

255

Beam current sensor  

DOE Patents [OSTI]

A current sensor for measuring the dc component of a beam of charged particles employs a superconducting pick-up loop probe, with twisted superconducting leads in combination with a Superconducting Quantum Interference Device (SQUID) detector. The pick-up probe is in the form of a single-turn loop, or a cylindrical toroid, through which the beam is directed and within which a first magnetic flux is excluded by the Meisner effect. The SQUID detector acts as a flux-to-voltage converter in providing a current to the pick-up loop so as to establish a second magnetic flux within the electrode which nulls out the first magnetic flux. A feedback voltage within the SQUID detector represents the beam current of the particles which transit the pick-up loop. Meisner effect currents prevent changes in the magnetic field within the toroidal pick-up loop and produce a current signal independent of the beam's cross-section and its position within the toroid, while the combination of superconducting elements provides current measurement sensitivities in the nano-ampere range.

Kuchnir, M.; Mills, F.E.

1984-09-28T23:59:59.000Z

256

Beam current sensor  

DOE Patents [OSTI]

A current sensor for measuring the DC component of a beam of charged particles employs a superconducting pick-up loop probe, with twisted superconducting leads in combination with a Superconducting Quantum Interference Device (SQUID) detector. The pick-up probe is in the form of a single-turn loop, or a cylindrical toroid, through which the beam is directed and within which a first magnetic flux is excluded by the Meisner effect. The SQUID detector acts as a flux-to-voltage converter in providing a current to the pick-up loop so as to establish a second magnetic flux within the electrode which nulls out the first magnetic flux. A feedback voltage within the SQUID detector represents the beam current of the particles which transit the pick-up loop. Meisner effect currents prevent changes in the magnetic field within the toroidal pick-up loop and produce a current signal independent of the beam's cross-section and its position within the toroid, while the combination of superconducting elements provides current measurement sensitivites in the nano-ampere range.

Kuchnir, Moyses (Elmhurst, IL); Mills, Frederick E. (Elburn, IL)

1987-01-01T23:59:59.000Z

257

Probing Organic Transistors with Infrared Beams  

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

Probing Organic Transistors with Infrared Beams Print Probing Organic Transistors with Infrared Beams Print Silicon-based transistors are well-understood, basic components of contemporary electronic technology. In contrast, there is growing need for the development of electronic devices based on organic polymer materials. Organic field-effect transistors (FETs) are ideal for special applications that require large areas, light weight, and structural flexibility. They also have the advantage of being easy to mass-produce at very low cost. However, even though this class of devices is finding a growing number of applications, electronic processes in organic materials are still not well understood. A group of researchers from the University of California and the ALS has succeeded in probing the intrinsic electronic properties of the charge carriers in organic FETs using infrared spectromicroscopy. The results of their study could help in the future development of sensors, large-area displays, and other plastic electronic components.

258

Publications, Oxide Molecular Beam Epitaxy Group, Condensed Matter Physics  

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

Publications Publications In Press M. P. M. Dean, G. Dellea, R. S. Springell, F. Yakhou-Harris, K. Kummer, N. B. Brookes, X. Liu, Y. Sun, J. Strle, T. Schmitt, L. Braicovich, G. Ghiringhelli, I. Bozovic and J. P. Hill. "Persistence of magnetic excitations in La2-xSrxCuOP4 from the undoped insulator to the heavily overdoped non-superconducting metal." Nature Materials (Submitted 2013). In press. J. Wu, O. Pelleg, G. Logvenov, A. T. Bollinger, Y. Sun, G. S. Boebinger, M. Vanevic, Z. Radovic and I. Bozovic. "Anomalous (in)dependence of interface superconductivity on carrier density." Nature Materials (Submitted 2012). In press. G. Dubuis, A. T. Bollinger, D. Pavuna and I. Bozovic. "On Field Effect Studies and Superconductor-Insulator Transition in High-Tc Cuprates."

259

Laboratories, Oxide Molecular Beam Epitaxy Group, Condensed Matter Physics  

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

Laboratories: Photo Tour Laboratories: Photo Tour MBE Laboratory MBE Laboratory MBE Chamber MBE Chamber Temperature Controllers MBE Computers and Servers Pneumatic Hoses Transport between MBE Laboratory and Nano-Lithography Laboratory Backside of MBE chamber during growth, lit by Nano-Lithography Laboratory Nano-Lithography Laboratory Processing Chamber Laminar Flow Hood Mask Aligner Profilometer Probe Station Wire Bonder X-Ray Diffraction and Chemistry Laboratory X-Ray Diffraction System X-Ray Diffraction System X-Ray Diffraction System Chemistry Laboratory Chemistry Laboratory Mutual Inductance, Transport and Field Effect Laboratory Field Effect Measurement system Liquid Helium-4 Dipstick for Mutual Inductance Transport Measurement System COMBI Hall Effect, COMBI Transport and Mutual Inductance Measurements Laboratory

260

Applied Super Conductor Group, Oxide Molecular Beam Epitaxy Group,  

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

AEMG Homepage AEMG Homepage Site Details Homepage Research Publications Presentations Facilities How to Contact Us Other Information Basic Energy Sciences Directorate Links BNL Site Index Can't View PDFs? Advanced Energy Materials Group Applied Superconductivity The applied superconductivity research (past funded by DOE Office of Electricity Delivery and Energy Reliability) is related to modernization of the U.S. power grid. One direction of the modernization is replacement of normal metal (copper, aluminum) transmission lines with High Temperature Superconducting (HTS) cables. Our group concentrates its effort on studying fundamental thermodynamics of nucleation and texture development of thick YBCO layers. High-performance YBCO layer is a critical element of modern second generation (2G) HTS wire.

Note: This page contains sample records for the topic "molecular beam mass" 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

Reactions of carbon atoms in pulsed molecular beams  

SciTech Connect (OSTI)

This research program consists of a broad scope of experiments designed to unravel the chemistry of atomic carbon in its two spin states, P and D, by using well-controlled initial conditions and state-resolved detection of products. Prerequisite to the proposed studies (and the reason why so little is known about carbon atom reactions), is the development of clean sources of carbon atoms. Therefore, in parallel with the studies of its chemistry and reaction dynamics, the authors continuously explore new, state-specific and efficient ways of producing atomic carbon. In the current program, C({sup 3}P) is produced via laser ablation of graphite, and three areas of study are being pursued: (i) exothermic reactions with small inorganic molecules (e.g., O{sub 2}, N{sub 2}O, NO{sub 2}) that can proceed via multiple pathways; (ii) the influence of vibrational and translational energy on endothermic reactions involving H-containing reactants that yield CH products (e.g., H{sub 2}O H{sub 2}CO); (iii) reactions of C({sup 3}P) with free radicals (e.g., HCO, CH{sub 3}O). In addition, the authors plan to develop a source of C({sup 1}D) atoms by exploiting the pyrolysis of diazotetrazole and its salts in the ablation source. Another important goal involves collaboration with theoreticians in order to obtain relevant potential energy surfaces, rationalize the experimental results and predict the roles of translational and vibrational energies.

Reisler, H. [Univ. of Southern California, Los Angeles (United States)

1993-12-01T23:59:59.000Z

262

MOLECULAR BEAM PHOTOIONIZATION AND GAS-SURFACE SCATTERING  

E-Print Network [OSTI]

K) Ion gauge, (H) Motor water cooling lines. chamber. (J)into a water cooled copper cylinder. The motor fits very TheCooling water cavity. shaft mounting pieces. (D) Motor. (F)

Ceyer, S.T.

2010-01-01T23:59:59.000Z

263

Collaborations, Oxide Molecular Beam Epitaxy Group, Condensed Matter  

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

Collaborations Collaborations Collaborations at BNL Experiment COBRA X-ray crystallography Researchers Dr. Ron Pindak, Dr. Hua Zhou (NSLS), Dr. Yitzak Yacobi (Technion, Israel) Object of Study The atomic structure of interfaces in M-I bilayers Experiment High-resolution electron microscopy Researchers Dr. Yimei Zhu (CMPMS) Object of Study The atomic structure of HTS heterostructures; bi-crystal grain boundaries Experiment Synchrotron X-ray crystallography Researchers Dr. John Hill (CMPMS) Object of Study Spin excitation spectrum in ultrathin LSCO layers Experiment Ultrafast electron diffraction Researchers Dr. Xijie Wang (NSLS) Object of Study Photo-induced lattice expansion Collaborations in the United States Experiment Resonant soft X-ray scattering (SXRS) Researchers Prof. Peter Abbamonte, Dr. Serban Smadici (University of Illinois at Urbana-Champaign)

264

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

265

Future Directions of Structural Mass Spectrometry using Hydroxyl Radical Footprinting  

SciTech Connect (OSTI)

Hydroxyl radical protein footprinting coupled to mass spectrometry has been developed over the last decade and has matured to a powerful method for analyzing protein structure and dynamics. It has been successfully applied in the analysis of protein structure, protein folding, protein dynamics, and protein-protein and protein-DNA interactions. Using synchrotron radiolysis, exposure of proteins to a 'white' X-ray beam for milliseconds provides sufficient oxidative modification to surface amino acid side chains, which can be easily detected and quantified by mass spectrometry. Thus, conformational changes in proteins or protein complexes can be examined using a time-resolved approach, which would be a valuable method for the study of macromolecular dynamics. In this review, we describe a new application of hydroxyl radical protein footprinting to probe the time evolution of the calcium-dependent conformational changes of gelsolin on the millisecond timescale. The data suggest a cooperative transition as multiple sites in different molecular subdomains have similar rates of conformational change. These findings demonstrate that time-resolved protein footprinting is suitable for studies of protein dynamics that occur over periods ranging from milliseconds to seconds. In this review, we also show how the structural resolution and sensitivity of the technology can be improved as well. The hydroxyl radical varies in its reactivity to different side chains by over two orders of magnitude, thus oxidation of amino acid side chains of lower reactivity are more rarely observed in such experiments. Here we demonstrate that the selected reaction monitoring (SRM)-based method can be utilized for quantification of oxidized species, improving the signal-to-noise ratio. This expansion of the set of oxidized residues of lower reactivity will improve the overall structural resolution of the technique. This approach is also suggested as a basis for developing hypothesis-driven structural mass spectrometry experiments.

J Kiselar; M Chance

2011-12-31T23:59:59.000Z

266

HIGHLY COMPRESSED ION BEAMS FOR HIGH ENERGY DENSITY SCIENCE  

E-Print Network [OSTI]

HIGHLY COMPRESSED ION BEAMS FOR HIGH ENERGY DENSITY SCIENCE A. Friedman1,2 , J.J.Barnard1,2 , R Energy Density regimes required for Inertial Fu- sion Energy and other applications. An interim goal we are pursuing, low to medium mass ions with energies just above the Bragg peak are directed onto

Wurtele, Jonathan

267

Gaussian Beams Enrique J. Galvez  

E-Print Network [OSTI]

Gaussian Beams Enrique J. Galvez Department of Physics and Astronomy Colgate University Copyright 2009 #12;ii #12;Contents 1 Fundamental Gaussian Beams 1 1.1 Spherical Wavefront in the Paraxial region . . . . . . . . . . . . . . . 1 1.2 Formal Solution of the Wave Equation . . . . . . . . . . . . . . . . . 3 1.2.1 Beam Spot w

Galvez, Enrique J. "Kiko"

268

Cryogenic Beam Loss Monitors for the Superconducting Magnets of the LHC  

E-Print Network [OSTI]

The Beam Loss Monitor detectors close to the interaction points of the Large Hadron Collider are currently located outside the cryostat, far from the superconducting coils of the magnets. In addition to their sensitivity to lost beam particles, they also detect particles coming from the experimental collisions, which do not contribute significantly to the heat deposition in the superconducting coils. In the future, with beams of higher energy and brightness resulting in higher luminosity, distinguishing between these interaction products and dangerous quench-provoking beam losses from the primary proton beams will be challenging. The system can be optimised by locating beam loss monitors as close as possible to the superconducting coils, inside the cold mass in a superfluid helium environment, at 1.9 K. The dose then measured by such Cryogenic Beam Loss Monitors would more precisely correspond to the real dose deposited in the coil. The candidates under investigation for such detectors are based on p+-n-n+ si...

Bartosik, MR; Sapinski, M; Kurfuerst, C; Griesmayer, E; Eremin, V; Verbitskaya, E

2014-01-01T23:59:59.000Z

269

Molecular Foundry  

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

Theory of Nanostructured Materials Theory of Nanostructured Materials The Theory of Nanostructured Materials Facility at the Molecular Foundry is focused on expanding our understanding of materials at the nanoscale. Our research connects the structural and dynamical properties of materials to their functions, such as electrical conductivity and storage, light-harvesting for electricity and fuel, or gas separation and sequestration. We develop and employ a broad range of tools, including advanced electronic-structure theory, excited-state methods, model Hamiltonians, and statistical mechanical models. This combination of approaches reveals how materials behave at the nanoscale, in pursuit of materials and devices that meet global energy and sustainability needs. Electronic structure of complex materials and interfaces for energy

270

LSST beam simulator  

Science Journals Connector (OSTI)

It is always important to test new imagers for a mosaic camera before device acceptance and constructing the mosaic. This is particularly true of the LSST CCDs due to the fast beam illumination: at long wavelengths there can be significant beam divergence (defocus) inside the silicon because of the long absorption length for photons near the band gap. Moreover, realistic sky scenes need to be projected onto the CCD focal plane Thus, we need to design and build an f/1.2 re-imaging system. The system must simulate the entire LSST1 operation, including a sky with galaxies and stars with approximately black-body spectra superimposed on a spatially diffuse night sky emission with its complex spectral features.

J A Tyson; J Sasian; C Claver; G Muller; K Gilmor; M Klint

2014-01-01T23:59:59.000Z

271

SSRL BEAM PORT SCHEDULE  

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

1-5 1-5 Nov. 05, 2007 Nov. 06, 2007 Nov. 07, 2007 Nov. 08, 2007 Nov. 09, 2007 Nov. 10, 2007 Nov. 11, 2007 Unscheduled FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI BEAM LINE 7-1 Nov. 05, 2007 Nov. 06, 2007 Nov. 07, 2007 Nov. 08, 2007 Nov. 09, 2007 Nov. 10, 2007 Nov. 11, 2007 Unscheduled FACI FACI FACI FACI FACI FACI

272

SSRL BEAM PORT SCHEDULE  

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

4 4 Mar. 15, 2004 Mar. 16, 2004 Mar. 17, 2004 Mar. 18, 2004 Mar. 19, 2004 Mar. 20, 2004 Mar. 21, 2004 DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN BEAM LINE 1-5 Mar. 15, 2004 Mar. 16, 2004 Mar. 17, 2004 Mar. 18, 2004 Mar. 19, 2004 Mar. 20, 2004 Mar. 21, 2004 DOWN DOWN DOWN DOWN DOWN DOWN DOWN

273

SSRL BEAM PORT SCHEDULE  

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

5-1 5-1 Nov. 28, 2005 Nov. 29, 2005 Nov. 30, 2005 Dec. 01, 2005 Dec. 02, 2005 Dec. 03, 2005 Dec. 04, 2005 MA FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI BEAM LINE 5-2 Nov. 28, 2005 Nov. 29, 2005 Nov. 30, 2005 Dec. 01, 2005 Dec. 02, 2005 Dec. 03, 2005 Dec. 04, 2005 MA FACI FACI FACI FACI FACI FACI

274

SSRL BEAM PORT SCHEDULE  

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

1-5 1-5 Nov. 10, 2008 Nov. 11, 2008 Nov. 12, 2008 Nov. 13, 2008 Nov. 14, 2008 Nov. 15, 2008 Nov. 16, 2008 DOWN FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI FACI BEAM LINE 7-1 Nov. 10, 2008 Nov. 11, 2008 Nov. 12, 2008 Nov. 13, 2008 Nov. 14, 2008 Nov. 15, 2008 Nov. 16, 2008 DOWN FACI FACI FACI FACI FACI FACI

275

All Beams 2013.xls  

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

1598 29 1079 9 1070 3.8 3.8 20.1 78 Kr 77.920 40 3117 140 622 20 602 14.2 14.4 41.4 Proton 1.007 40 40 0.1 8148 1.2 8147 0.012 0.012 0.56 Available Beams 40 A MeV 25 A MeV 15 A MeV...

276

Axion beams at HERA?  

E-Print Network [OSTI]

If the recently observed anomaly in the PVLAS experiment is due to the axion, then the powerful beams of synchrotron photons, propagating through high magnetic field of the HERA beamline, become strong axion sources. This gives a unique opportunity of detection of the axion-photon interactions by installing a small detector in the HERA tunnel, and to corroborate the axion hypothesis within a few days of running.

K. Piotrzkowski

2007-01-09T23:59:59.000Z

277

Proton beam therapy facility  

SciTech Connect (OSTI)

It is proposed to build a regional outpatient medical clinic at the Fermi National Accelerator Laboratory (Fermilab), Batavia, Illinois, to exploit the unique therapeutic characteristics of high energy proton beams. The Fermilab location for a proton therapy facility (PTF) is being chosen for reasons ranging from lower total construction and operating costs and the availability of sophisticated technical support to a location with good access to patients from the Chicago area and from the entire nation. 9 refs., 4 figs., 26 tabs.

Not Available

1984-10-09T23:59:59.000Z

278

Physics with Rare Isotope Beams  

SciTech Connect (OSTI)

Using stable and radioactive beams provided by ATLAS nuclear reactions of special interest in astrophysics have been studied with emphasis on breakout from the hot CNO cycle to the rp-process. The masses of nuclear fragments provided by a strong fission source have been measured in order to help trace the path of the r process. 8Li ions produced by the d(7Li,8Li)n reaction have been trapped and the electrons and alphas emitted in the ensuing beta-decay measured. The neutrino directions were therefore determined, which leads to a measurement of the electron-neutrino correlation. The energies and kinematics are such that a sensitive search for any tensor admixture could be performed and an upper limit of 0.6% was placed on any such admixture. Earlier work on the electromagnetic form factors of the proton was extended. Graduate students were active participants in all of these eperiments, which formed the basis for six PhD theses.

Segel, Ralph E. [Northwestern University] [Northwestern University

2013-11-08T23:59:59.000Z

279

Nanoscale molecularly imprinted polymers and method thereof  

DOE Patents [OSTI]

Nanoscale molecularly imprinted polymers (MIP) having polymer features wherein the size, shape and position are predetermined can be fabricated using an xy piezo stage mounted on an inverted microscope and a laser. Using an AMF controller, a solution containing polymer precursors and a photo initiator are positioned on the xy piezo and hit with a laser beam. The thickness of the polymeric features can be varied from a few nanometers to over a micron.

Hart, Bradley R. (Brentwood, CA); Talley, Chad E. (Brentwood, CA)

2008-06-10T23:59:59.000Z

280

Fast beam studies of free radical photodissociation  

SciTech Connect (OSTI)

The authors have developed a novel technique for studying the photodissociation spectroscopy and dynamics of free radicals. In these experiments, radicals are generated by laser photodetachment of a fast (6-8 keV) mass-selected negative ion beam. The resulting radicals are photodissociated with a second laser, and the photofragments are collected and detected with high efficiency using a microchannel plate detector. The overall process is: ABC{sup -} {yields} ABC + e{sup -} {yields} A + BC, AB + C. Two types of fragment detection schemes are used. To map out the photodissociation cross-section of the radical, the photodissociation laser is scanned and the total photofragment yield is measured as a function of wavelength. In other experiments, the photodissociation frequency is fixed and the photofragment masses, kinetic energy release, and scattering angle is determined for each photodissociation event.

Neumark, D.M. [Lawrence Berkeley Laboratory, CA (United States)

1993-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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

Nondestructive Damage Detection in General Beams  

E-Print Network [OSTI]

is to provide NDE methodologies that simultaneously identify the location, the extent, and the severity of damage in general beams. By general beams, we mean beyond Euler-Bernoulli beams (i.e. slender beams) to deep beams and stubby beams whose response may...

Dincal, Selcuk

2010-12-08T23:59:59.000Z

282

Attraction and repulsion of multi-color laser beams in plasmas: a computational study  

SciTech Connect (OSTI)

The nonlinear interaction of high-power multi-color laser beams in plasmas is investigated numerically. Both the relativistic mass increase and the driven plasma wave contribute to the mutual beam-beam interaction and to the development of the electromagnetic cascade. The propagation of the individual cascade sidebands is modelled in the paraxial approximation. The resulting set of coupled nonlinear envelope equations is solved numerically using a newly developed pseudospectral method. We predict that two beams intersecting in the plasma can either attract or deflect each other depending on whether their frequency detuning is slightly below or above the electron Langmuir frequency.

Yi, S. A.; Kalmykov, S.; Shvets, G. [Department of Physics and Institute for Fusion Studies, University of Texas at Austin, One University Station C1500, Austin, Texas 78712 (United States)

2009-01-22T23:59:59.000Z

283

Beam-Beam Interaction Simulations with Guinea Pig  

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

5 5 SLAC-TN-03-070 September 2003 Beam-Beam Interaction Simulations with Guinea Pig C. Sramek, T. O. Raubenheimer, A. Seryi, M. Woods, J. Yu Stanford Linear Accelerator Center Stanford University Stanford, CA Abstract: At the interaction point of a particle accelerator, various phenomena occur that are known as beam-beam effects. Incident bunches of electrons (or positrons) experience strong electromagnetic fields from the opposing bunches, which leads to electron deflection, beamstrahlung and the creation of electron/positron pairs and hadrons due to two-photon exchange. In addition, the beams experience a "pinch effect" which focuses each beam and results in either a reduction or expansion of their vertical size. Finally, if a

284

Simulation of beam-beam effects in tevatron  

SciTech Connect (OSTI)

The Fermilab accelerator complex is in the middle of an upgrade plan Fermilab III. In the last phase of this upgrade the luminosity of the Tevatron will increase by at least one order of magnitude. In order to keep the number of interactions per crossing manageable for experiments, the number of bunches will be increased from 6 {times} 6 to 36 {times} 36 and finally to {approximately}100 {times} 100 bunches. The beam dynamics of the Tevatron has been studied from Beam-Beam effect point of view in a ``Strong-Weak`` representation with a single particle being tracked in presence of other beam. This paper describes the beam-beam effect in 6 {times} 6 operation of Tevatron.

Mishra, C.S.; Assadi, S. [Fermi National Accelerator Lab., Batavia, IL (United States); Talman, R. [Cornell Univ., Ithaca, NY (United States)

1995-08-01T23:59:59.000Z

285

A combined beta-beam and electron capture neutrino experiment  

E-Print Network [OSTI]

The next generation of long baseline neutrino experiments will aim at determining the value of the unknown mixing angle, theta_{13}, the type of neutrino mass hierarchy and the presence of CP-violation in the lepton sector. Beta-beams and electron capture experiments have been studied as viable candidates for long baseline experiments. They use a very clean electron neutrino beam from the beta-decays or electron capture decays of boosted ions. In the present article we consider an hybrid setup which combines a beta-beam with an electron capture beam by using boosted Ytterbium ions. We study the sensitivity to the CP-violating phase delta and the theta_{13} angle, the CP-discovery potential and the reach to determine the type of neutrino mass hierarchy for this type of long baseline experiment. The analysis is performed for different neutrino beam energies and baselines. Finally, we also discuss how the results would change if a better knowledge of some of the assumed parameters was achieved by the time this experiment could take place.

J. Bernabeu; C. Espinoza; C. Orme; S. Palomares-Ruiz; S. Pascoli

2009-02-27T23:59:59.000Z

286

The chemistry of high-mass star formation  

E-Print Network [OSTI]

This paper reviews the chemistry of star-forming regions, with an emphasis on the formation of high-mass stars. We first outline the basic molecular processes in dense clouds, their implementation in chemical models, and techniques to measure molecular abundances. Then, recent observational, theoretical and laboratory developments are reviewed on the subjects of hot molecular cores, cosmic-ray ionization, depletion and deuteration, and oxygen chemistry. The paper concludes with a summary of outstanding problems and future opportunities.

Floris F. S. van der Tak

2005-06-07T23:59:59.000Z

287

SSRL BEAM PORT SCHEDULE  

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

1-4 1-4 Oct. 30, 2006 Oct. 31, 2006 Nov. 01, 2006 Nov. 02, 2006 Nov. 03, 2006 Nov. 04, 2006 Nov. 05, 2006 DOWN Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled BEAM LINE 2-1 Oct. 30, 2006 Oct. 31, 2006 Nov. 01, 2006 Nov. 02, 2006 Nov. 03, 2006 Nov. 04, 2006 Nov. 05, 2006 DOWN 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON

288

SSRL BEAM PORT SCHEDULE  

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

5 5 Mar. 15, 2004 Mar. 16, 2004 Mar. 17, 2004 Mar. 18, 2004 Mar. 19, 2004 Mar. 20, 2004 Mar. 21, 2004 DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN DOWN BEAM LINE 9-1 Mar. 15, 2004 Mar. 16, 2004 Mar. 17, 2004 Mar. 18, 2004 Mar. 19, 2004 Mar. 20, 2004 Mar. 21, 2004 Unscheduled CHANGE/8837 A.COHE 8837 A.COHEN 8837 A.COHEN 8837 A.COHEN 8837 A.COHEN 8837 A.COHEN

289

Magnetically operated beam dump for dumping high power beams in a neutral beamline  

DOE Patents [OSTI]

It is an object of this invention to provide a beam dump system for a neutral beam generator which lowers the time-averaged power density of the beam dump impingement surface. Another object of this invention is to provide a beam dump system for a neutral particle beam based on reionization and subsequent magnetic beam position modulation of the beam onto a beam dump surface to lower the time-averaged power density of the beam dump ion impingement surface.

Dagenhart, W.K.

1984-01-27T23:59:59.000Z

290

LANL: Ion Beam Materials Laboratory  

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

Ion Beam Materials Laboratory (IBML) is a Los Ion Beam Materials Laboratory (IBML) is a Los Alamos National Laboratory resource devoted to materi- als research through the use of ion beams. Current major research areas include surface characterization through ion beam analysis techniques, surface modification and materials synthesis through ion implantation technology, and radiation damage stud- ies in gases, liquids, and solids. The laboratory's core is a 3.2 MV tandem ion accelerator and a 200 kV ion implanter together with several beam lines. Attached to each beam line is a series of experimental stations that support various research programs. The operation of IBML and its interactions with users are organized around core facilities and experimental stations. The IBML provides and operates the core facilities as well as supports

291

High flux photon beam monitor  

SciTech Connect (OSTI)

We have designed two photon beam position monitors for use on our x-ray storage ring beam lines. In both designs, a pair of tungsten blades, separated by a pre-determined gap, intercepts a small fraction of the incoming beam. Due to photoemission, an electrical signal is generated which is proportional to the amount of beam intercepted. The thermal load deposited in the blade is transferred by a heat pipe to a heat exchanger outside the vacuum chamber. A prototype monitor with gap adjustment capability was fabricated and tested at a uv beam line. The results show that the generated electrical signal is a good measurement of the photon beam position. In the following sections, design features and test results are discussed.

Mortazavi, P.; Woodle, M.; Rarback, H.; Shu, D.; Howells, M.

1985-01-01T23:59:59.000Z

292

Beam-Induced Backgrounds in the CLIC Detectors  

E-Print Network [OSTI]

The beam parameters of the proposed CLIC linear electron-positron collider with a centre-of-mass energy of up to 3 TeV will lead to high rates of beam-induced background events. In this note simulation studies of ?? ? hadron interactions and of incoherent electron-positron pair production are presented. The CLIC detector concepts and their optimisation to reduce background occupancies are described. The characteristics of the events are discussed and resulting occupancies and energy deposits, as well as expected levels of both total ionising dose and displacement damage in the detectors are discussed.

Dannheim, D

2012-01-01T23:59:59.000Z

293

Particle Detector / Beam Current Transformer  

E-Print Network [OSTI]

Particle Detector / Beam Current Transformer Analysis December 8, 2009 Harold G. Kirk #12;ShotSignal,A.U. Proton Bunch Number Beam Current Transformer - 17011 0 2 4 6 8 0 2 4 6 8 10 12 14 16 18 20 Integrated Transformer Pump 187829 (au) Probe 196504 (au) Ratios: Beam Current 1.046 SF 1.019 2.9% difference #12;Shot

McDonald, Kirk

294

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

295

Beam-strahlung effects in e-p collider  

SciTech Connect (OSTI)

The electromagnetic fields produced by one beam in an interaction point of a colliding-beam facility cause to the emission of synchrotron radiation by the other beam. This effect, the beam strahlung, for the e+e/sup -/ colliders has been considered by several authors, and they have pointed out that the effect is very important consideration at very-high-energy e+e/sup -/ colliders. At the first glance, the beam-strahlung effect can play an important role in the e-p collision due to the fact that the circulating currents in the collider are much higher than those of the e+e/sup -/ machine. However the detailed study shows that is not the case because of the collision geometry involved. What follows in this note is the beam-strahlung derivations using the method previously used by Hofmann and Keil. The difference between this note and that of Hofman and Keil is that in the case of e+e/sup -/ collider, equal mass particles are involved in the consideration and, in the e-p case, the electrons radiate and the protons provide the electromagnetic fields.

Cho, Y.

1982-09-01T23:59:59.000Z

296

The Gas Flow from the Gas Attenuator to the Beam Line  

SciTech Connect (OSTI)

The gas leak from the gas attenuator to the main beam line of the Linac Coherent Light Source has been evaluated, with the effect of the Knudsen molecular beam included. It has been found that the gas leak from the gas attenuator of the present design, with nitrogen as a working gas, does not exceed 10{sup -5} torr x l/s even at the highest pressure in the main attenuation cell (20 torr).

Ryutov, D.D.

2010-12-03T23:59:59.000Z

297

Broad-band beam buncher  

DOE Patents [OSTI]

A broad-band beam buncher is disclosed, comprising an evacuated housing, an electron gun therein for producing an electron beam, a buncher cavity having entrance and exit openings through which the beam is directed, grids across such openings, a source providing a positive DC voltage between the cavity and the electron gun, a drift tube through which the electron beam travels in passing through such cavity, grids across the ends of such drift tube, gaps being provided between the drift tube grids and the entrance and exit grids, a modulator for supplying an ultrahigh frequency modulating signal to the drift tube for producing velocity modulation of the electrons in the beam, a drift space in the housing through which the velocity modulated electron beam travels and in which the beam is bunched, and a discharge opening from such drift tube and having a grid across such opening through which the bunched electron beam is discharged into an accelerator or the like. The buncher cavity and the drift tube may be arranged to constitute an extension of a coaxial transmission line which is employed to deliver the modulating signal from a signal source. The extended transmission line may be terminated in its characteristic impedance to afford a broad-band response and the device as a whole designed to effect broad-band beam coupling, so as to minimize variations of the output across the response band.

Goldberg, David A. (Walnut Creek, CA); Flood, William S. (Berkeley, CA); Arthur, Allan A. (Martinez, CA); Voelker, Ferdinand (Orinda, CA)

1986-01-01T23:59:59.000Z

298

ANL Beams and Applications Seminar  

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

Argonne Beams & Applications Seminar Search APS ... Search Argonne Home > Argonne Home > Advanced Photon Source > Seminar Archive 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003...

299

High-Performance Mass Spectrometry Facility  

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

HPMSF Overview HPMSF Overview Section 2-4-1 High-Performance Mass Spectrometry Facility The High-Performance Mass Spectrometry Facility (HPMSF) provides state-of-the-art mass spectrometry (MS) and separations instrumentation that has been refined for leading-edge analysis of biological problems with a primary emphasis on proteomics. Challenging research in proteomics, cell signaling, cellular molecular machines, and high-molecular weight systems receive the highest priority for access to the facility. Current research activities in the HPMSF include proteomic analyses of whole cell lysates, analyses of organic macro-molecules and protein complexes, quantification using isotopically labeled growth media, targeted proteomics analyses of subcellular fractions, and nucleic acid analysis of

300

Accelerators, Beams And Physical Review Special Topics - Accelerators And Beams  

SciTech Connect (OSTI)

Accelerator science and technology have evolved as accelerators became larger and important to a broad range of science. Physical Review Special Topics - Accelerators and Beams was established to serve the accelerator community as a timely, widely circulated, international journal covering the full breadth of accelerators and beams. The history of the journal and the innovations associated with it are reviewed.

Siemann, R.H.; /SLAC

2011-10-24T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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

Useful Graphs and Charts - Ion Beams - Radiation Effects Facility...  

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

Ion Beams Available Beams Beam Change Times Measurements Useful Graphs Useful Graphs and Charts LET vs. Range in Si Graphs: 15 MeVu Beams 24.8 MeVu Beams 40 MeVu Beams...

302

SSRL BEAM PORT SCHEDULE  

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

1, 2002 Nov. 18, 2002 Nov. 25, 2002 Dec. 02, 2002 1, 2002 Nov. 18, 2002 Nov. 25, 2002 Dec. 02, 2002 Dec. 09, 2002 Dec. 16, 2002 Dec. 23, 2002 Dec. 30, 2002 Jan. 06, 2003 Jan. 13, 2003 Jan. 20, 2003 Jan. 27, 2003 Feb. 03, 2003 Feb. 10, 2003 Feb. 17, 2003 Feb. 24, 2003 Mar. 03, 2003 Mar. 10, 2003 Mar. 17, 2003 Mar. 24, 2003 Mar. 31, 2003 Back to Table of Contents WEEK OF Nov. 11, 2002 Nov. 11, 2002 Nov. 12, 2002 Nov. 13, 2002 Nov. 14, 2002 Nov. 15, 2002 Nov. 16, 2002 Nov. 17, 2002 BEAM LINE 1-4 Nov. 11, 2002 Nov. 12, 2002 Nov. 13, 2002 Nov. 14, 2002 Nov. 15, 2002 Nov. 16, 2002 Nov. 17, 2002 Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled

303

SSRL BEAM PORT SCHEDULE  

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

Nov. 04, 2013 Nov. 11, 2013 Nov. 18, 2013 Nov. 25, 2013 Nov. 04, 2013 Nov. 11, 2013 Nov. 18, 2013 Nov. 25, 2013 Dec. 02, 2013 Dec. 09, 2013 Dec. 16, 2013 Dec. 23, 2013 Dec. 30, 2013 Jan. 06, 2014 Jan. 13, 2014 Jan. 20, 2014 Jan. 27, 2014 Feb. 03, 2014 Back to Table of Contents WEEK OF Nov. 04, 2013 Ops Re-start Nov. 04, 2013 Nov. 05, 2013 Nov. 06, 2013 Nov. 07, 2013 Nov. 08, 2013 Nov. 09, 2013 Nov. 10, 2013 BEAM LINE 1-4 Nov. 04, 2013 Nov. 05, 2013 Nov. 06, 2013 Nov. 07, 2013 Nov. 08, 2013 Nov. 09, 2013 Nov. 10, 2013 DOWN DOWN DOWN 8891 C.TASSONE 8891 C.TASSONE 8891 C.TASSONE 8891 C.TASSONE

304

SSRL BEAM PORT SCHEDULE  

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

1-4 1-4 Nov. 05, 2007 Nov. 06, 2007 Nov. 07, 2007 Nov. 08, 2007 Nov. 09, 2007 Nov. 10, 2007 Nov. 11, 2007 Unscheduled Unscheduled 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY Unscheduled CHANGE/8051 M.TONE 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY Unscheduled 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY BEAM LINE 2-1 Nov. 05, 2007 Nov. 06, 2007 Nov. 07, 2007 Nov. 08, 2007 Nov. 09, 2007 Nov. 10, 2007 Nov. 11, 2007 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON 3157* M.MONTERO-CA 3087 L.FUENTES-COB 3087 L.FUENTES-COB

305

SSRL BEAM PORT SCHEDULE  

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

1-5 1-5 Nov. 28, 2005 Nov. 29, 2005 Nov. 30, 2005 Dec. 01, 2005 Dec. 02, 2005 Dec. 03, 2005 Dec. 04, 2005 MA 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ BEAM LINE 7-1 Nov. 28, 2005 Nov. 29, 2005 Nov. 30, 2005 Dec. 01, 2005 Dec. 02, 2005 Dec. 03, 2005 Dec. 04, 2005 MA DOWN DOWN DOWN DOWN DOWN DOWN

306

SSRL BEAM PORT SCHEDULE  

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

5-4 5-4 Nov. 05, 2007 Nov. 06, 2007 Nov. 07, 2007 Nov. 08, 2007 Nov. 09, 2007 Nov. 10, 2007 Nov. 11, 2007 Unscheduled 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU CHANGE/8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU BEAM LINE 8-1 Nov. 05, 2007 Nov. 06, 2007 Nov. 07, 2007 Nov. 08, 2007 Nov. 09, 2007 Nov. 10, 2007 Nov. 11, 2007 8821 D.Brehmer 8821 D.Brehmer 8821 D.Brehmer 3064* S.SUN 3075 M.GARNER 3075 M.GARNER 3075 M.GARNER

307

SSRL BEAM PORT SCHEDULE  

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

4, 2013 Nov. 11, 2013 Nov. 18, 2013 Nov. 25, 2013 4, 2013 Nov. 11, 2013 Nov. 18, 2013 Nov. 25, 2013 Dec. 02, 2013 Dec. 09, 2013 Dec. 16, 2013 Dec. 23, 2013 Dec. 30, 2013 Jan. 06, 2014 Jan. 13, 2014 Jan. 20, 2014 Jan. 27, 2014 Feb. 03, 2014 Back to Table of Contents WEEK OF Nov. 04, 2013 Ops Re-start Nov. 04, 2013 Nov. 05, 2013 Nov. 06, 2013 Nov. 07, 2013 Nov. 08, 2013 Nov. 09, 2013 Nov. 10, 2013 BEAM LINE 5-4 Nov. 04, 2013 Nov. 05, 2013 Nov. 06, 2013 Nov. 07, 2013 Nov. 08, 2013 Nov. 09, 2013 Nov. 10, 2013 DOWN DOWN DOWN DOWN DOWN DOWN DOWN

308

SSRL BEAM PORT SCHEDULE  

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

1-4 1-4 Nov. 28, 2005 Nov. 29, 2005 Nov. 30, 2005 Dec. 01, 2005 Dec. 02, 2005 Dec. 03, 2005 Dec. 04, 2005 MA 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE CHANGE/8840 J.POPL 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE BEAM LINE 2-1 Nov. 28, 2005 Nov. 29, 2005 Nov. 30, 2005 Dec. 01, 2005 Dec. 02, 2005 Dec. 03, 2005 Dec. 04, 2005 MA 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON

309

SSRL BEAM PORT SCHEDULE  

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

5-4 5-4 Nov. 15, 2010 Nov. 16, 2010 Nov. 17, 2010 Nov. 18, 2010 Nov. 19, 2010 Nov. 20, 2010 Nov. 21, 2010 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU BEAM LINE 8-1 Nov. 15, 2010 Nov. 16, 2010 Nov. 17, 2010 Nov. 18, 2010 Nov. 19, 2010 Nov. 20, 2010 Nov. 21, 2010 Unscheduled Unscheduled Unscheduled 3269 S.SUN 3269 S.SUN 3269 S.SUN 3269 S.SUN

310

Tunable source of terahertz radiation using molecular modulation  

E-Print Network [OSTI]

Tunable source of terahertz radiation using molecular modulation D. D. Yavuz* and J. J. Weber a high power and widely tunable coher- ent source of THz radiation remains a very challenging task of terahertz (THz) radiation that is based on Raman down-shifting of an infrared laser beam using highly

Yavuz, Deniz

311

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

312

Broad-band beam buncher  

DOE Patents [OSTI]

A broad-band beam bunther is disclosed, comprising an evacuated housing, an electron gun therein for producing an electron beam, a buncher cavity having entrance and exit openings through which the beam is directed, grids across such openings, a source providing a positive DC voltage between the cavity and the electron gun, a drift tube through which the electron beam travels in passing through such cavity, grids across the ends of such drift tube, gaps being provided between the drift tube grids and the entrance and exit grids, a modulator for supplying an ultrahigh frequency modulating signal to the drift tube for producing velocity modulation of the electrons in the beam, a drift space in the housing through which the velocity modulated electron beam travels and in which the beam is bunched, and a discharge opening from such drift tube and having a grid across such opening through which the bunched electron beam is discharged into an accelerator or the like. The buncher cavity and the drift tube may be arranged to constitute an extension of a coaxial transmission line which is employed to deliver the modulating signal from a signal source. The extended transmission line may be terminated in its characteristic impedance to afford a broad-

Goldberg, D.A.; Flood, W.S.; Arthur, A.A.; Voelker, F.

1984-03-20T23:59:59.000Z

313

Measurements of aperture and beam lifetime using movable beam scrapers in Indus-2 electron storage ring  

SciTech Connect (OSTI)

In this paper, the measurements of vertical and horizontal aperture which are available for stable beam motion in Indus-2 at beam energy 2.5 GeV using movable beam scrapers are presented. These beam scrapers are installed in one of the long straight sections in the ring. With the movement of beam scrapers towards the beam centre, the beam lifetime is measured. The beam lifetime data obtained from the movement of vertical and horizontal beam scrapers are analyzed. The contribution of beam loss due to beam-gas scattering (vacuum lifetime) and electron-electron scattering within a beam bunch (Touschek lifetime) is separated from the measured beam lifetime at different positions of the beam scrapers. Vertical and horizontal beam sizes at scrapers location are estimated from the scraper movement towards the beam centre in quantum lifetime limit and their values closely agree with measured value obtained using X-ray diagnostic beamline.

Kumar, Pradeep; Ghodke, A. D.; Karnewar, A. K.; Holikatti, A. C.; Yadav, S.; Puntambekar, T. A.; Singh, G. [Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)] [Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Singh, P. [Bhabha Atomic Research Centre, Mumbai (India)] [Bhabha Atomic Research Centre, Mumbai (India)

2013-12-15T23:59:59.000Z

314

Linear Electric Field Time-Of-Flight Ion Mass Spectrometers  

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

Linear Electric Field Time-Of-Flight Ion Mass Spectrometers Linear Electric Field Time-Of-Flight Ion Mass Spectrometers Linear Electric Field Time-Of-Flight Ion Mass Spectrometers Time-of-flight mass spectrometer comprising a first drift region and a second drift region enclosed within an evacuation chamber. Available for thumbnail of Feynman Center (505) 665-9090 Email Linear Electric Field Time-Of-Flight Ion Mass Spectrometers Time-of-flight mass spectrometer comprising a first drift region and a second drift region enclosed within an evacuation chamber; a means of introducing an analyte of interest into the first drift region; a pulsed ionization source which produces molecular ions from said analyte of interest; a first foil positioned between the first drift region and the second drift region, which dissociates said molecular ions into constituent

315

IonBeamMicroFab  

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

Ion Beam Manufacture of Microscale Ion Beam Manufacture of Microscale Tools and Components Manufacturing Technologies Sandia Manufacturing Science &Technology's Focused Ion Beam (FIB) laboratory provides an opportunity for research, development and prototyping. Currently, our scientists are devel- oping methods for ion beam sculpting microscale tools, components and devices. This includes shaping of specialty tools such as end-mills, turning tools and indenters. Many of these have been used in ultra-precision machining DOE applications. Additionally, staff are developing the capability to ion mill geo- metrically-complex features and substrates. This includes the ability to sputter predeter- mined curved shapes of various symmetries and periodicities. Capabilities and Expertise * Two custom-built focused ion beam sys-

316

Impact load mitigation in sandwich beams using local resonators  

E-Print Network [OSTI]

Dynamic response of sandwich beams with resonators embedded in the cores subjected to impact loads is studied. Using finite element models the effectiveness of various local resonator frequencies under a given impact load is compared to the behavior of an equivalent mass beam. It is shown that addition of appropriately chosen local resonators into the sandwich beam is an effective method of improving its flexural bending behavior under impact loads. The effect of a given local resonance frequency under different impact load durations is also studied. It is demonstrated that the choice of appropriate local resonance frequency depends on the impact duration. Further, by performing transverse impact experiments, the finite element models are verified and the advantage of using internal resonators under impact loading conditions is demonstrated.

Sharma, B

2015-01-01T23:59:59.000Z

317

EMSL Research and Capability Development Proposals Developing in-spectrometer photochemistry and integration of molecular imaging techniques  

E-Print Network [OSTI]

-of-flight secondary ion mass spectrometry system (ToF-SIMS) for understanding molecular distribution on the surface microscopy with a mercury lamp as an excitation source on a ToF-SIMS for identifying molecular distribution

318

Mass Spectrometer: Orbitrap | EMSL  

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

Software (ISIS): A Machine Learning Approach to Tandem Mass Spectral Identification of Lipids. Liquid chromatography-mass spectrometry-based metabolomics has gained importance...

319

Time Structure of the LANSCE Beam  

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

Beam One of the greatest strengths of the LANSCE facility is that it can produce proton beams with a wide range of time structures. Time Structure of the LANSCE Beam One of the...

320

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.

Note: This page contains sample records for the topic "molecular beam mass" 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

MOLECULAR GAS IN LUMINOUS GALACTIC NUCLEI N. Z. SCOVILLE AND A. J. BAKER  

E-Print Network [OSTI]

MOLECULAR GAS IN LUMINOUS GALACTIC NUCLEI N. Z. SCOVILLE AND A. J. BAKER California Institute­wave interferometry has clearly shown the existence of enormous masses (10 9 \\Gamma 10 10 M fi ) of molecular gas. In these systems, molecular gas is an obvious source of fuel for nuclear starbursts and active galactic nuclei (AGN

Baker, Andrew J.

322

SSRL BEAM PORT SCHEDULE  

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

7-1 7-1 Nov. 15, 2010 Nov. 16, 2010 Nov. 17, 2010 Nov. 18, 2010 Nov. 19, 2010 Nov. 20, 2010 Nov. 21, 2010 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 2B87 I.SEVRIOUKOVA 2B87 I.SEVRIOUKOVA 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ MC CHECKOUT/2B87 2B87 I.SEVRIOUKOVA 2B87 I.SEVRIOUKOVA 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 2B87 I.SEVRIOUKOVA 2B87 I.SEVRIOUKOVA 2B87 I.SEVRIOUKOVA BEAM LINE 9-1 Nov. 15, 2010 Nov. 16, 2010 Nov. 17, 2010 Nov. 18, 2010 Nov. 19, 2010 Nov. 20, 2010 Nov. 21, 2010 8866 T.DOUKOV 8866 T.DOUKOV 8866 T.DOUKOV 8866 T.DOUKOV 8866 T.DOUKOV FACI FACI

323

SSRL BEAM PORT SCHEDULE  

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

Feb. 14, 2005 Feb. 21, 2005 Feb. 28, 2005 Mar. 07, 2005 Feb. 14, 2005 Feb. 21, 2005 Feb. 28, 2005 Mar. 07, 2005 Mar. 14, 2005 Mar. 21, 2005 Mar. 28, 2005 Apr. 04, 2005 Apr. 11, 2005 Apr. 18, 2005 Apr. 25, 2005 May 02, 2005 May 09, 2005 May 16, 2005 May 23, 2005 May 30, 2005 Jun. 06, 2005 Jun. 13, 2005 Jun. 20, 2005 Jun. 27, 2005 Jul. 04, 2005 Jul. 11, 2005 Jul. 18, 2005 Jul. 25, 2005 Aug. 01, 2005 Back to Table of Contents WEEK OF Feb. 14, 2005 Feb. 14, 2005 Feb. 15, 2005 Feb. 16, 2005 Feb. 17, 2005 Feb. 18, 2005 Feb. 19, 2005 Feb. 20, 2005 BEAM LINE 1-5 Feb. 14, 2005 Feb. 15, 2005 Feb. 16, 2005 Feb. 17, 2005 Feb. 18, 2005 Feb. 19, 2005 Feb. 20, 2005 8858 D.HARRINGTON 8858 D.HARRIN/DOWN 8858 D.HARRINGTON 8858 D.HARRINGTON 8858 D.HARRINGTON 8858 D.HARRINGTON 8858 D.HARRINGTON

324

SSRL BEAM PORT SCHEDULE  

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

1, 2013 Nov. 18, 2013 Nov. 25, 2013 Dec. 02, 2013 1, 2013 Nov. 18, 2013 Nov. 25, 2013 Dec. 02, 2013 Dec. 09, 2013 Dec. 16, 2013 Dec. 23, 2013 Dec. 30, 2013 Jan. 06, 2014 Jan. 13, 2014 Jan. 20, 2014 Jan. 27, 2014 Feb. 03, 2014 Feb. 10, 2014 Feb. 17, 2014 Feb. 24, 2014 Back to Table of Contents WEEK OF Nov. 11, 2013 Nov. 11, 2013 Nov. 12, 2013 Nov. 13, 2013 Nov. 14, 2013 Nov. 15, 2013 Nov. 16, 2013 Nov. 17, 2013 BEAM LINE 7-1 Nov. 11, 2013 Nov. 12, 2013 Nov. 13, 2013 Nov. 14, 2013 Nov. 15, 2013 Nov. 16, 2013 Nov. 17, 2013 8803 C.Smith 8803 C.Smith 8803 C.Smith 8803 C.Smith 8803 C.Smith 4B02 A.Yeh 8050 C.Smith 8803 C.Smith 8803 C.Smith 8803 C.Smith 8803 C.Smith Unscheduled MC CHECKOUT/8050 8050 C.Smith

325

SSRL BEAM PORT SCHEDULE  

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

7-1 7-1 Oct. 26, 2009 Oct. 27, 2009 Oct. 28, 2009 Oct. 29, 2009 Oct. 30, 2009 Oct. 31, 2009 Nov. 01, 2009 CHANGE/8803* C.SMI 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH BEAM LINE 9-1 Oct. 26, 2009 Oct. 27, 2009 Oct. 28, 2009 Oct. 29, 2009 Oct. 30, 2009 Oct. 31, 2009 Nov. 01, 2009 CHANGE/8861* I.MAT 8861* I.MATHEWS 8861* I.MATHEWS 8861* I.MATHEWS 8861* I.MATHEWS 8861* I.MATHEWS 8861* I.MATHEWS

326

Probing Organic Transistors with Infrared Beams  

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

Probing Organic Transistors with Infrared Beams Probing Organic Transistors with Infrared Beams Print Wednesday, 26 July 2006 00:00 Silicon-based transistors are well-understood,...

327

Electron beam machining using rotating and shaped beam power distribution  

DOE Patents [OSTI]

An apparatus and method for electron beam (EB) machining (drilling, cutting and welding) that uses conventional EB guns, power supplies, and welding machine technology without the need for fast bias pulsing technology. The invention involves a magnetic lensing (EB optics) system and electronic controls to: 1) concurrently bend, focus, shape, scan, and rotate the beam to protect the EB gun and to create a desired effective power-density distribution, and 2) rotate or scan this shaped beam in a controlled way. The shaped beam power-density distribution can be measured using a tomographic imaging system. For example, the EB apparatus of this invention has the ability to drill holes in metal having a diameter up to 1000 .mu.m (1 mm or larger), compared to the 250 .mu.m diameter of laser drilling.

Elmer, John W. (Pleasanton, CA); O'Brien, Dennis W. (Livermore, CA)

1996-01-01T23:59:59.000Z

328

Alight a beam and beaming light: A theme with variations  

SciTech Connect (OSTI)

The interaction of light (coherent and incoherent) with charged particle beams is explored in various configurations: incoherent scattering of coherent light (laser) from an incoherent particle beam (high temperature), coherent scattering of coherent light (laser) from a {open_quotes}cold{close_quotes} (bunched) beam, femtosecond generation of particle and light beams via {open_quotes}optical slicing{close_quotes} and Thomson/Compton scattering techniques, etc. The domains of ultrashort temporal duration (femtoseconds) as well as ultrashort wavelengths (x rays and shorter), with varying degrees of coherence, are explored. The relevance to a few critical areas of research in the natural sciences, e.g., ultrafast material, chemical and biological processes, protein folding, particle phase space cooling, etc. are touched upon. All the processes discussed involve proper interpretation and understanding of coherent states of matter and radiation, as well as the quality and quantity of information and energy embedded in them. {copyright} {ital 1998 American Institute of Physics.}

Chattopadhyay, S. [Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, California94720 (United States)] [Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, California94720 (United States)

1998-05-01T23:59:59.000Z

329

Electron beam machining using rotating and shaped beam power distribution  

DOE Patents [OSTI]

An apparatus and method are disclosed for electron beam (EB) machining (drilling, cutting and welding) that uses conventional EB guns, power supplies, and welding machine technology without the need for fast bias pulsing technology. The invention involves a magnetic lensing (EB optics) system and electronic controls to: (1) concurrently bend, focus, shape, scan, and rotate the beam to protect the EB gun and to create a desired effective power-density distribution, and (2) rotate or scan this shaped beam in a controlled way. The shaped beam power-density distribution can be measured using a tomographic imaging system. For example, the EB apparatus of this invention has the ability to drill holes in metal having a diameter up to 1,000 {micro}m (1 mm or larger), compared to the 250 {micro}m diameter of laser drilling. 5 figs.

Elmer, J.W.; O`Brien, D.W.

1996-07-09T23:59:59.000Z

330

Diagnostic beam absorber in Mu2e beam line  

SciTech Connect (OSTI)

Star density, hadron flux, and residual dose distributions are calculated around the {mu}2e diagnostic beam absorber. Corresponding surface and ground water activation, and air activation are presented as well.

Rakhno, Igor; /Fermilab

2011-03-01T23:59:59.000Z

331

Mass spectrometric immunoassay  

DOE Patents [OSTI]

Rapid mass spectrometric immunoassay methods for detecting and/or quantifying antibody and antigen analytes utilizing affinity capture to isolate the analytes and internal reference species (for quantification) followed by mass spectrometric analysis of the isolated analyte/internal reference species. Quantification is obtained by normalizing and calibrating obtained mass spectrum against the mass spectrum obtained for an antibody/antigen of known concentration.

Nelson, Randall W; Williams, Peter; Krone, Jennifer Reeve

2013-07-16T23:59:59.000Z

332

Mass spectrometric immunoassay  

DOE Patents [OSTI]

Rapid mass spectrometric immunoassay methods for detecting and/or quantifying antibody and antigen analytes utilizing affinity capture to isolate the analytes and internal reference species (for quantification) followed by mass spectrometric analysis of the isolated analyte/internal reference species. Quantification is obtained by normalizing and calibrating obtained mass spectrum against the mass spectrum obtained for an antibody/antigen of known concentration.

Nelson, Randall W (Phoenix, AZ); Williams, Peter (Phoenix, AZ); Krone, Jennifer Reeve (Granbury, TX)

2007-12-04T23:59:59.000Z

333

Probing Organic Transistors with Infrared Beams  

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

Probing Organic Transistors with Probing Organic Transistors with Infrared Beams Probing Organic Transistors with Infrared Beams Print Wednesday, 26 July 2006 00:00 Silicon-based transistors are well-understood, basic components of contemporary electronic technology. In contrast, there is growing need for the development of electronic devices based on organic polymer materials. Organic field-effect transistors (FETs) are ideal for special applications that require large areas, light weight, and structural flexibility. They also have the advantage of being easy to mass-produce at very low cost. However, even though this class of devices is finding a growing number of applications, electronic processes in organic materials are still not well understood. A group of researchers from the University of California and the ALS has succeeded in probing the intrinsic electronic properties of the charge carriers in organic FETs using infrared spectromicroscopy. The results of their study could help in the future development of sensors, large-area displays, and other plastic electronic components.

334

EMSL - Molecular Science Computing  

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

computing Resources and Techniques Molecular Science Computing - Sophisticated and integrated computational capabilities, including scientific consultants, software, Cascade...

335

Molecular vibration demonstrations  

Science Journals Connector (OSTI)

Molecular vibration demonstrations ... Two dynamic models that illustrate the normal-mode vibrations of the water and benzene molecules. ...

George Turrell; Robert Demol

1987-01-01T23:59:59.000Z

336

edited1_TopQuarkMass  

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

CALCULATE THE TOP QUARK MASS CALCULATE THE TOP QUARK MASS TEACHER NOTES DESCRIPTION Students use momentum conservation, energy conservation and two-dimensional vector addition to calculate the mass of the heaviest of the six known quarks. They gather data from data plots from the DØ experiment at Fermilab. The events were chosen carefully; all of the decay products moved in a plane perpendicular to the beam. This makes the vector addition much simpler. STANDARDS National Science Education Standards (U.S. National Research Council) * Physical Science Content Standard B: As a result of this activity . . . students should develop an understanding of: o Conservation of energy and increase in disorder. o Interactions in energy and matter. LEARNING OBJECTIVES Students will know and be able to:

337

The Beam | Open Energy Information  

Open Energy Info (EERE)

Zip: 2446 Product: The Beam is a start-up company that looks to establish an online retail portal that would market and sell clean energy-related products to consumers....

338

STOCHASTIC COOLING FOR BUNCHED BEAMS.  

SciTech Connect (OSTI)

Problems associated with bunched beam stochastic cooling are reviewed. A longitudinal stochastic cooling system for RHIC is under construction and has been partially commissioned. The state of the system and future plans are discussed.

BLASKIEWICZ, M.

2005-05-16T23:59:59.000Z

339

Center for Beam Physics, 1992  

SciTech Connect (OSTI)

This report contains the following information on the center for beam physics: Facilities; Organizational Chart; Roster; Profiles of Staff; Affiliates; Center Publications (1991--1993); and 1992 Summary of Activities.

Not Available

1993-06-01T23:59:59.000Z

340

Neutron beam testing of triblades  

SciTech Connect (OSTI)

PowerXCell 8i processors and Opterons in four IBM Triblades were tested at LANSCE. The hazard rate when the beam was aimed at the Opterons was higher than when it was aimed at the Cell processors.

Michalak, Sarah E [Los Alamos National Laboratory; Du Bois, Andrew J [Los Alamos National Laboratory; Storlie, Curtis B [Los Alamos National Laboratory; Rust, William N [Los Alamos National Laboratory; Du Bois, David H [Los Alamos National Laboratory; Modl, David G [Los Alamos National Laboratory; Quinn, Heather M [Los Alamos National Laboratory; Blanchard, Sean P [Los Alamos National Laboratory; Manuzzato, Andrea [UNIV DEGLI STUDI DI PADOVA ITALY

2011-01-31T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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.


341

Neon Ion Beam Lithography (NIBL)  

E-Print Network [OSTI]

Existing techniques for electron- and ion-beam lithography, routinely employed for nanoscale device fabrication and mask/mold prototyping, do not simultaneously achieve efficient (low fluence) exposure and high resolution. ...

Winston, Donald

342

Beam bunch feedback  

SciTech Connect (OSTI)

When the electromagnetic fields that are excited by the passage of a bundle of charged particles persist to act upon bunches that follow, then the motions of the bunches are coupled. This action between bunches circulating on a closed orbit can generate growing patterns of bunch excursions. Such growth can often be suppressed by feedback systems that detect the excursion and apply corrective forces to the bunches. To be addressed herein is feedback that acts on motions of the bunch body centers. In addition to being useful for suppressing the spontaneous growth of coupled-bunch motions, such feedback can be used to damp transients in bunches injected into an accelerator or storage ring; for hadrons which lack strong radiation damping, feedback is needed to avoid emittance growth through decoherence. Motions excited by noise in magnetic fields or accelerating rf can also be reduced by using this feedback. Whether the action is on motions that are transverse to the closed orbit or longitudinal, the arrangement is the same. Bunch position is detected by a pickup and that signal is processed and directed to a kicker that may act upon the same bunch or some other portion of the collective beam pattern. Transverse motion is an oscillation with angular frequency {nu}{perpendicular}{omega}{sub o} where {omega}{sub o} is the orbital frequency 2{pi}{line_integral}o. Longitudinal synchrotron oscillation occurs at frequency {omega} {sub s} = {nu}{sub s}{omega}{sub o}. The former is much more rapid, {nu}{perpendicular} being on the order of 10 while {nu}{sub s} is typically about 10{sup minus 1} to 10 {sup minus 2}.

Lambertson, G.

1995-09-01T23:59:59.000Z

343

On the emergence of molecular structure  

SciTech Connect (OSTI)

The structure of (a{sup {+-}},a{sup {+-}},b{sup {+-}})-type Coulombic systems is characterized by the effective ground-state density of the a-type particles, computed via nonrelativistic quantum mechanics without introduction of the Born-Oppenheimer approximation. A structural transition is observed when varying the relative mass of the a- and b-type particles, e.g., between atomic H{sup -} and molecular H{sub 2}{sup +}. The particle-density profile indicates a molecular-type behavior for the positronium ion, Ps{sup -}.

Matyus, Edit; Reiher, Markus [Laboratory of Physical Chemistry, ETH Zuerich, Wolfgang-Pauli-Strasse 10, CH-8093 Zuerich (Switzerland); Hutter, Juerg [Institute of Physical Chemistry, University of Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland); Mueller-Herold, Ulrich [Institute of Biogeochemistry and Pollutant Dynamics, ETH Zuerich, Universitaetstrasse 16, CH-8092 Zuerich (Switzerland)

2011-05-15T23:59:59.000Z

344

Search for Lepton Number Violating Charged Current Processes with Neutrino Beams  

E-Print Network [OSTI]

We propose a new idea to test a class of loop-induced neutrino mass mechanisms by searching for lepton number violating charged current processes with incident of a neutrino beam. The expected rates of these processes are estimated based on some theoretical assumptions. They turn out to be sizable so that detection of such processes could be possible at near detectors in future highly intense neutrino-beam facilities.

Shinya Kanemura; Yoshitaka Kuno; Toshihiko Ota

2012-05-25T23:59:59.000Z

345

Secondary Ion Mass Spectrometry Imaging of Dictyostelium discoideum Aggregation Streams  

SciTech Connect (OSTI)

High resolution imaging mass spectrometry could become a valuable tool for cell and developmental biology, but both, high spatial and mass spectral resolution are needed to enable this. In this report, we employed Bi3 bombardment time-of-flight (Bi3 ToF-SIMS) and C60 bombardment Fourier transform ion cyclotron resonance secondary ion mass spectrometry (C60 FTICR-SIMS) to image Dictyostelium discoideum aggregation streams. Nearly 300 lipid species were identified from the aggregation streams. High resolution mass spectrometry imaging (FTICR-SIMS) enabled the generation of multiple molecular ion maps at the nominal mass level and provided good coverage for fatty acyls, prenol lipids, and sterol lipids. The comparison of Bi3 ToF-SIMS and C60 FTICR-SIMS suggested that while the first provides fast, high spatial resolution molecular ion images, the chemical complexity of biological samples warrants the use of high resolution analyzers for accurate ion identification.

Debord, J. Daniel; Smith, Donald F.; Anderton, Christopher R.; Heeren, Ronald M.; Pasa-Tolic, Ljiljana; Gomer, Richard H.; Fernandez-Lima, Francisco A.

2014-06-09T23:59:59.000Z

346

Electron beam diagnostic for profiling high power beams  

DOE Patents [OSTI]

A system for characterizing high power electron beams at power levels of 10 kW and above is described. This system is comprised of a slit disk assembly having a multitude of radial slits, a conducting disk with the same number of radial slits located below the slit disk assembly, a Faraday cup assembly located below the conducting disk, and a start-stop target located proximate the slit disk assembly. In order to keep the system from over-heating during use, a heat sink is placed in close proximity to the components discussed above, and an active cooling system, using water, for example, can be integrated into the heat sink. During use, the high power beam is initially directed onto a start-stop target and after reaching its full power is translated around the slit disk assembly, wherein the beam enters the radial slits and the conducting disk radial slits and is detected at the Faraday cup assembly. A trigger probe assembly can also be integrated into the system in order to aid in the determination of the proper orientation of the beam during reconstruction. After passing over each of the slits, the beam is then rapidly translated back to the start-stop target to minimize the amount of time that the high power beam comes in contact with the slit disk assembly. The data obtained by the system is then transferred into a computer system, where a computer tomography algorithm is used to reconstruct the power density distribution of the beam.

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

2008-03-25T23:59:59.000Z

347

Probing the Short Range Spin Dependent Interactions by Polarized $^{3}He$ Atom Beams  

E-Print Network [OSTI]

Experiments using polarized $^{3}He$ atom beams to search for short range spin dependent forces are proposed. High intensity, high polarization, small beam size $^{3}He$ atom beams have been successfully produced and used in surface science researches. By incorporating background reduction designs as combination shielding by $\\mu$-metal and superconductor and double beam pathes, the precision of spin rotation angle per unit length could be improved by a factor of $\\sim10^{4}$. By this precision, in combination with using a high density and low magnetic susceptibility sample source mass,and reversing one beam path if necessary, sensitivities on three different types of spin dependent interactions could be possibly improved by as much as $\\sim10^{2}$ to $\\sim10^{8}$ over the current experiments at the millimeter range.

Yan, H

2014-01-01T23:59:59.000Z

348

Probing the Short Range Spin Dependent Interactions by Polarized $^{3}He$ Atom Beams  

E-Print Network [OSTI]

Experiments using polarized $^{3}He$ atom beams to search for short range spin dependent forces are proposed. High intensity, high polarization, small beam size $^{3}He$ atom beams have been successfully produced and used in surface science researches. By incorporating background reduction designs as combination shielding by $\\mu$-metal and superconductor and double beam pathes, the precision of spin rotation angle per unit length could be improved by a factor of $\\sim10^{4}$. By this precision, in combination with using a high density and low magnetic susceptibility sample source mass,and reversing one beam path if necessary, sensitivities on three different types of spin dependent interactions could be possibly improved by as much as $\\sim10^{2}$ to $\\sim10^{8}$ over the current experiments at the millimeter range.

H. Yan

2014-07-22T23:59:59.000Z

349

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 uraniumplutonium 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 CO and CC 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 H2Omethanol 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

350

Molecular Gas in nearby Early-Type Powerful Classical Radio Galaxies  

E-Print Network [OSTI]

We report a survey for molecular gas in nearby powerful radio galaxies. Eight of the eighteen radio galaxies observed were detected with molecular masses in the range 10^7--10^9 Msun, similar to the same survey we performed towards 3C radio galaxies. The upper limits of molecular gas in the remainder are typically of 10^8 Msun, indicating that very few radiogalaxies have molecular gas reservoir with more than 10^9 Msun.

Stephane Leon; Jeremy Lim; Francoise Combes; Dinh-V-Trung

2002-11-13T23:59:59.000Z

351

Mass determination of megadalton-DNA Electrospray Ions usingCharge Detection Mass Spectrometry  

SciTech Connect (OSTI)

Charge detection mass spectrometry (CD-MS) has been used to determine the mass of double-stranded, circular DNA and single-stranded, circular DNA in the range of 2500 to 8000 base pairs (1.5-5.0 MDa). Simultaneous measurement of the charge and velocity of an electrostatically accelerated ion allows a mass determination of the ion, with instrument calibration determined independently of samples. Positive ion mass spectra of electrosprayed commercial DNA samples supplied in tris(hydroxymethyl)ethylenediamine tetraacetic acid buffer, diluted in 50 vol. percent acetonitrile, were obtained without cleanup of the sample. ACD mass spectrum constructed from 3000 ion measurements takes 10 min to acquire and yields the DNA molecular mass directly (mass resolution = 6). The data collected represent progress toward a more automatable alternative to sizing of DNA by gel electrophoresis. In addition to the mass spectra, CD-MS generates charge versus mass plots, which provide another means to investigate the creation and fate of large electrospray ions.

Schultz, Jocelyn C.; Hack, Christopher; Benner, Henry W.

1997-10-01T23:59:59.000Z

352

MEIS: Molecular Environmental & Interface Science  

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

People People BL 11-2 Reports &Publications Model Compound Library SixPACK Glitch Curves MES User Resources & Instrumentation Environmental Remediation Science at SSRL MEIS Home SSRL Stanford EMSI SLAC Beam line resources and instrumentation Fundamental and applied research Why synchrotrons for environmental science? Molecular Environmental Science (MES) research at SSRL focuses on the fundamental interfacial, molecular- and nano-scale processes that control contaminant and nutrient cycling in the biosphere with the goal of elucidating global elemental cycles and anthropogenic influences on the environment. Key areas of investigation include the: (a) Structural chemistry of water and dissolved solutes, (b) Structural chemistry and reactivity of complex natural environmental materials with respect to heavy

353

THE BOLOCAM GALACTIC PLANE SURVEY. III. CHARACTERIZING PHYSICAL PROPERTIES OF MASSIVE STAR-FORMING REGIONS IN THE GEMINI OB1 MOLECULAR CLOUD  

SciTech Connect (OSTI)

We present the 1.1 mm Bolocam Galactic Plane Survey (BGPS) observations of the Gemini OB1 molecular cloud complex, and targeted NH{sub 3} observations of the BGPS sources. When paired with molecular spectroscopy of a dense gas tracer, millimeter observations yield physical properties such as masses, radii, mean densities, kinetic temperatures, and line widths. We detect 34 distinct BGPS sources above 5{sigma} = 0.37 Jy beam{sup -1} with corresponding 5{sigma} detections in the NH{sub 3}(1,1) transition. Eight of the objects show water maser emission (20%). We find a mean millimeter source FWHM of 1.12 pc and a mean gas kinetic temperature of 20 K for the sample of 34 BGPS sources with detections in the NH{sub 3}(1,1) line. The observed NH{sub 3} line widths are dominated by non-thermal motions, typically found to be a few times the thermal sound speed expected for the derived kinetic temperature. We calculate the mass for each source from the millimeter flux assuming the sources are isothermal and find a mean isothermal mass within a 120'' aperture of 230 {+-} 180 M{sub sun}. We find a total mass of 8400 M{sub sun} for all BGPS sources in the Gemini OB1 molecular cloud, representing 6.5% of the cloud mass. By comparing the millimeter isothermal mass to the virial mass calculated from the NH{sub 3} line widths within a radius equal to the millimeter source size, we find a mean virial parameter (M{sub vir}/M {sub iso}) of 1.0 {+-} 0.9 for the sample. We find mean values for the distributions of column densities of 1.0 x 10{sup 22} cm{sup -2} for H{sub 2}, and 3.0 x 10{sup 14} cm{sup -2} for NH{sub 3}, giving a mean NH{sub 3} abundance of 3.0 x 10{sup -8} relative to H{sub 2}. We find volume-averaged densities on the order of 10{sup 3}-10{sup 4} cm{sup -3}. The sizes and densities suggest that in the Gem OB1 region the BGPS is detecting the clumps from which stellar clusters form, rather than smaller, higher density cores where single stars or small multiple systems form.

Dunham, Miranda K.; Evans, Neal J.; Harvey, Paul; Merello, Manuel [Department of Astronomy, The University of Texas at Austin, 1 University Station C1400, Austin, TX 78712-0259 (United States); Rosolowsky, Erik [University of British Columbia, Okanagan, 3333 University Way, Kelowna BC V1V 1V7 (Canada); Cyganowski, Claudia J. [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States); Aguirre, James [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Bally, John; Battersby, Cara; Ginsburg, Adam; Glenn, Jason; Stringfellow, Guy S. [CASA, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Bradley, Eric Todd [Department of Physics, University of Central Florida, 4000 Central Florida Boulevard, Orlando, FL 32816-2385 (United States); Dowell, Darren [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91104 (United States); Drosback, Meredith [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States); Schlingman, Wayne; Shirley, Yancy L. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Walawender, Josh [Institute for Astronomy, University of Hawaii, 640 N. Aohoku Place, Hilo, HI 96720 (United States); Williams, Jonathan P., E-mail: nordhaus@astro.as.utexas.ed [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

2010-07-10T23:59:59.000Z

354

Negative Muon Chemistry: The Quantum Muon Effect and the Finite Nuclear Mass Effect  

Science Journals Connector (OSTI)

Negative Muon Chemistry: The Quantum Muon Effect and the Finite Nuclear Mass Effect ... In this approach electrons and muons are described as quantum waves. ... The nonrelativistic Hamiltonian, Htot, of a molecular system containing Ne electrons, N? muons, and Nnuc nuclei is(1)here m? is the muon mass and MA and ZA are the mass and charge of nucleus A, respectively. ...

Edwin Posada; Flix Moncada; Andrs Reyes

2014-09-04T23:59:59.000Z

355

A Timoshenko beam theory with pressure corrections for layered orthotropic beams  

E-Print Network [OSTI]

A Timoshenko beam theory with pressure corrections for layered orthotropic beams Graeme J. Kennedya of Michigan, Ann Arbor, MI 48109, USA Abstract A Timoshenko beam theory for layered orthotropic beams and rotation variables that provide the kinematic description of the beam, stress and strain moments used

Papalambros, Panos

356

Physics Reach of the Beta Beam  

E-Print Network [OSTI]

Beta Beams are designed to produce pure (anti)electron neutrino beams and could be an elegant and powerful option for the search of leptonic CP violating processes. In this paper will be quantified the physics reach of a CERN based Beta Beam and of a Super Beam - Beta Beam combination. The CP phase $\\delta$ sensitivity results to be comparable to a Neutrino Factory for $\\sin^2{\\theta_{13}}$ values greater than $10^{-4}$.

Mauro Mezzetto

2003-02-07T23:59:59.000Z

357

EMSL - Mass Spectrometry  

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

mass-spectrometry Proteomics Capabilities High resolution and mass accuracy Fourier-transform ion cyclotron resonance (FT-ICR) spectrometers, from 6 Tesla (T) to 15T and 21T in...

358

mass communication advertising &  

E-Print Network [OSTI]

mass communication advertising & public relations introduction. Graduate programs in the Department of Mass Communication, Advertising, and Public Relations provide an entry to a wide spectrum of careers the opportunity to create content, campaigns, strategy, and research in public relations, advertising

Finzi, Adrien

359

Machine and Beam Delivery Updates  

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

MAchine and Beam delivery Updates FY13 MAchine and Beam delivery Updates FY13 Summary of Beam Delivery: FACET Summary Feb_15_22.pdf FACET Summary Feb_15_22.pdf FACET Summary Feb_23_Mar_1.pdf FACET Summary Feb_23_Mar_1.pdf FACET Summary Mar_2_8.pdf FACET Summary Mar_2_8.pdf FACET Summary Mar_9_15.pdf FACET Summary Mar_9_15.pdf FACET Summary Mar_16_22.pdf FACET Summary Mar_16_22.pdf FACET Summary Mar_23_29.pdf FACET Summary Mar_23_29.pdf FACET Summary Mar_30_Apr_5.pdf FACET Summary Mar_30_Apr_5.pdf FACET Summary Apr_6_12.pdf FACET Summary Apr_6_12.pdf FACET Summary Apr_27_May_3.pdf FACET Summary Apr_27_May_3.pdf FACET Summary May_4_10.pdf FACET Summary May_4_10.pdf Emittance Stability in Sector 2_31513.pdf Emittance Stability in Sector 2_31513.pdf FACET beam operations readiness with R56.pdf FACET beam operations readiness with R56.pdf (6/19/2013)

360

Elbow mass flow meter  

DOE Patents [OSTI]

Elbow mass flow meter. The present invention includes a combination of an elbow pressure drop generator and a shunt-type mass flow sensor for providing an output which gives the mass flow rate of a gas that is nearly independent of the density of the gas. For air, the output is also approximately independent of humidity.

McFarland, Andrew R. (College Station, TX); Rodgers, John C. (Santa Fe, NM); Ortiz, Carlos A. (Bryan, TX); Nelson, David C. (Santa Fe, NM)

1994-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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

Beam-plasma coupling effects on the stopping power of dense plasmas  

Science Journals Connector (OSTI)

The stopping power for ion beams in dense plasmas is investigated on the basis of quantum kinetic equations. Strong correlations between the beam ions and the plasma particles which occur for high ion charge numbers and strongly coupled plasmas are treated on the level of the statically screened T-matrix (binary collision) approximation. Dynamic screening effects are included using a combined scheme which considers both close collisions and collective effects. Applying this approach, the ion charge number dependence of the stopping power is determined. The result is a modification of the Zb2 scaling law. In particular, the stopping power is reduced for strong beam-plasma coupling. Good agreement is found between T-matrix results and simulation data (particle-in-cell and molecular dynamics) for low beam velocities.

D. O. Gericke and M. Schlanges

1999-07-01T23:59:59.000Z

362

AFRD - Center for Beam Physics  

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

Center for Beam Physics Center for Beam Physics Home Organization Outreach and Diversity Highlights Safety Links Intramural Group photo of our staff CBP staff, May 2011 CBP in the News: Read about an innovation in super-precise timing and synchronization; and a look toward the next generation of electron guns with responsiveness and brightness needed by future free-electron lasers such as those in the Next Generation Light Source initiative. Who We Are and What We Do The Center for Beam Physics (CBP) is a resource for meeting the challenges of accelerator science, and a source of many innovative concepts, within the Accelerator and Fusion Research Division. We have core expertise in accelerator physics and theory, accelerator modeling using high performance computing, and instrumentation,

363

REQUIREMENTS AND GUIDELINES FOR NSLS EXPERIMENTAL BEAM LINE VACUUM SYSTEMS-REVISION B.  

SciTech Connect (OSTI)

Typical beam lines are comprised of an assembly of vacuum valves and shutters referred to as a ''front end'', optical elements to monochromatize, focus and split the photon beam, and an experimental area where a target sample is placed into the photon beam and data from the interaction is detected and recorded. Windows are used to separate sections of beam lines that are not compatible with storage ring ultra high vacuum. Some experimental beam lines share a common vacuum with storage rings. Sections of beam lines are only allowed to vent up to atmospheric pressure using pure nitrogen gas after a vacuum barrier is established to protect ring vacuum. The front end may only be bled up when there is no current in the machine. This is especially true on the VUV storage ring where for most experiments, windows are not used. For the shorter wavelength, more energetic photons of the x-ray ring, beryllium windows are used at various beam line locations so that the monochromator, mirror box or sample chamber may be used in a helium atmosphere or rough vacuum. The window separates ring vacuum from the environment of the downstream beam line components. The stored beam lifetime in the storage rings and the maintenance of desirable reflection properties of optical surfaces depend upon hydrocarbon-free, ultra-high vacuum systems. Storage ring vacuum systems will operate at pressures of {approximately} 1 x 10{sup {minus}10} Torr without beam and {approximately} 1 x 10{sup {minus}9} Torr with beam. Systems are free of hydrocarbons in the sense that no pumps, valves, etc. containing organics are used. Components are all-metal, chemically cleaned and bakeable. To the extent that beam lines share a common vacuum with the storage ring, the same criteria will hold for beam line components. The design philosophy for NSLS beam lines is to use all-metal, hydrocarbon-free front end components and recommend that experimenters use this approach for common vacuum hardware downstream of front ends. O-ring-sealed valves, if used, are not permitted upstream of the monochromator exit aperture. It will be the responsibility of users to demonstrate that their experiment will not degrade the pressure or quality of the storage ring vacuum. As a matter of operating policy, all beam lines will be monitored for prescribed pressure and the contribution of high mass gases to this pressure each time a beam line has been opened to ring vacuum.

FOERSTER,C.

1999-05-01T23:59:59.000Z

364

The Beam Profile Calculation for Diagnostic Neutral Beam on HT-7 Tokamak  

Science Journals Connector (OSTI)

A new calculation method is introduced for convergence beam intensity. The program based on this method is prepared for beam intensity distribution and beam power calculation. Taking the HT-7 DNB as a referenc...

Lizhen Liang; Chundong Hu

2013-10-01T23:59:59.000Z

365

Effect of Beam-Beam Interactions on Stability of Coherent Oscillations in a Muon Collider  

SciTech Connect (OSTI)

In order to achieve peak luminosity of a muon collider in the 10{sup 34}/cm{sup 2}/s range the number of muons per bunch should be of the order of a few units of 10{sup 12} rendering the beam-beam parameter as high as 0.1 per IP. Such strong beam-beam interaction can be a source of instability if the working point is chosen close to a coherent beam-beam resonance. On the other hand, the beam-beam tunespread can provide a mechanism of suppression of the beam-wall driven instabilities. In this report the coherent instabilities driven by beam-beam and beam-wall interactions are studied with the help of BBSS code for the case of 1.5 TeV c.o.m muon collider.

Alexahin, Y.; /Fermilab; Ohmi, K.; /KEK, Tsukuba

2012-05-01T23:59:59.000Z

366

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

367

Crossed beam reaction of atomic carbon C ( 3 P j ) with hydrogen sulfide, H 2 S (X 1 A 1 ): Observation of the thioformyl radical, HCS (X 2 A?)  

Science Journals Connector (OSTI)

One of the simplest organosulfur reactions that between ground statecarbon atoms C ( 3 P j ) and hydrogen sulfide H 2 S (X 1 A 1 ) was studied at an average collision energy of 21.0 kJ? mol ?1 using the crossed molecular beams technique. The product angular distribution and time-of-flight spectra of m/e=45 ( HC 32 S ) were monitored. Forward-convolution fitting of our data yields an almost isotropic center-of-mass angular flux-distribution whereas the center-of-mass translational energy flux distribution peaks at about 50 kJ? mol ?1 indicating a tight exit transition state from the decomposing thiohydroxycarbene HCSH complex to the reaction products. The high energy cut-off of the translational energy flux distribution is consistent with the formation of the thioformyl radical HCS in its X 2 A electronic ground state. The first experimental verification of an existing thiohydroxycarbene intermediate and the rigorous assignment of the HCS radical product under single collision conditions explicitly suggest inclusion of the title reaction in chemical reaction networks of molecular clouds TMC-1 and OMC-1 the outflow of the carbon star IRC+10216 Shoemaker/Levy 9 impact-induced nonequilibrium sulfur chemistry in the Jovian atmosphere as well as combustion of sulfur containing coal.

R. I. Kaiser; W. Sun; A. G. Suits

1997-01-01T23:59:59.000Z

368

Engineering Molecular Transformations  

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

Engineering Molecular Transformations for Sustainable Energy Conversion Matthew Neurock* Departments of Chemical Engineering and Chemistry, UniVersity of Virginia, CharlottesVille,...

369

Accelerated Molecular Dynamics Methods  

Broader source: Energy.gov [DOE]

This presentation on Accelerated Molecular Dynamics Methods was given at the DOE Theory Focus Session on Hydrogen Storage Materials on May 18, 2006.

370

Nonparaxial Mathieu and Weber accelerating beams  

E-Print Network [OSTI]

We demonstrate both theoretically and experimentally nonparaxial Mathieu and Weber accelerating beams, generalizing the concept of previously found accelerating beams. We show that such beams bend into large angles along circular, elliptical or parabolic trajectories but still retain nondiffracting and self-healing capabilities. The circular nonparaxial accelerating beams can be considered as a special case of the Mathieu accelerating beams, while an Airy beam is only a special case of the Weber beams at the paraxial limit. Not only generalized nonparaxial accelerating beams open up many possibilities of beam engineering for applications, but the fundamental concept developed here can be applied to other linear wave systems in nature, ranging from electromagnetic and elastic waves to matter waves.

Peng Zhang; Yi Hu; Tongcang Li; Drake Cannan; Xiaobo Yin; Roberto Morandotti; Zhigang Chen; Xiang Zhang

2012-10-23T23:59:59.000Z

371

Stochastic cooling of bunched beams  

SciTech Connect (OSTI)

Numerical simulation studies are presented for transverse and longitudinal stochastic cooling of bunched particle beams. Radio frequency buckets of various shapes (e.g. rectangular, parabolic well, single sinusoidal waveform) are used to investigate the enhancement of phase space cooling by nonlinearities of synchrotron motion. The connection between the notions of Landau damping for instabilities and mixing for stochastic cooling are discussed. In particular, the need for synchrotron frequency spread for both Landau damping and good mixing is seen to be comparable for bunched beams.

Bisognano, J.J.; Chattopadhyay, S.

1981-03-01T23:59:59.000Z

372

Thermal stresses in laminated beams  

E-Print Network [OSTI]

24. Normal Stress Distribution for a Cantilever Laminated Beam, T-Z sinzx/L --------------- 58 m. i 25. Axial Stress Distribution for a Cantilever Laminated Bearq, T-T (2z/8+1) 2 mi 27. Normal Stress Distribution for ("/L) ? ---- 6 O 2 a... 80 100 Stress o (psi) xz. i Fig. 14. Normal Stress Distribution for a Simply-Supported Laminated Beam, T=z (2z/H+1) (x/L) 2 2 m. 1 6 4 x Classical Solution o Present Solution Load: Sinusoidal I F 0 100 200 300 400 Stress c (ps&) XX. 1 500...

Marcano, Victor Manuel

2012-06-07T23:59:59.000Z

373

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

374

State-to-state dynamics of molecular energy transfer  

SciTech Connect (OSTI)

The goal of this research program is to elucidate the elementary dynamical mechanisms of vibrational and rotational energy transfer between molecules, at a quantum-state resolved level of detail. Molecular beam techniques are used to isolate individual molecular collisions, and to control the kinetic energy of collision. Lasers are used both to prepare specific quantum states prior to collision by stimulated-emission pumping (SEP), and to measure the distribution of quantum states in the collision products by laser-induced fluorescence (LIF). The results are interpreted in terms of dynamical models, which may be cast in a classical, semiclassical or quantum mechanical framework, as appropriate.

Gentry, W.R.; Giese, C.F. [Univ. of Minnesota, Minneapolis (United States)

1993-12-01T23:59:59.000Z

375

MOLECULAR AND ATOMIC LINE SURVEYS OF GALAXIES. II. UNBIASED ESTIMATES OF THEIR STAR FORMATION MODE  

SciTech Connect (OSTI)

We make use of our 'minimal' cold interstellar medium emission line model that predicts the molecular and atomic line emission per unit dense, star-forming gas mass to examine the utility of key line ratios in surveys of the so-called star formation 'mode' as traced by {xi}{sub SF} = M{sub dense}(H{sub 2})/M{sub total}(H{sub 2}). We argue that {xi}{sub SF} and its proxies provide very sensitive, extinction-free discriminators of rapid starburst/merger-driven versus secular quiescent/disk-like stellar mass assembly, with the most promising diagnostic to be applied in the near-future being CO J(4 {yields} 3)/ [C I]({sup 3} P{sub 1} {yields} {sup 3} P{sub 0}). These lines are accessible across nearly the full range 0 < z < 2 (thus covering the bulk of galaxy evolution) with the Atacama Large Millimeter Array. In addition to their diagnostic power, another advantage of this combination is the similar observed frequencies ({Delta}{nu}{sub 0} Almost-Equal-To 30 GHz) of the lines, resulting in nearly spatially matched beams for a fixed aperture, thus mitigating the effects of resolution/morphology bias in the interpretation of galaxy-averaged line ratios. Finally, we discuss the capability of deep blind redshift surveys with the high-frequency component of the Square Kilometer Array (SKA) in discovering H{sub 2}-rich galaxies with very low {xi}{sub SF} values. These could be the progenitors of starburst galaxies seen prior to the onset of star formation; such galaxies could be a class of extreme outliers from local (gas surface density)-(star formation rate) scaling laws, which would exclude them from current star formation or stellar-mass-selected samples. Our conservative model suggests that SKA could detect such systems residing at z {approx} 3 at a rate of 20-200 hr{sup -1}.

Papadopoulos, Padelis P. [Max Planck Institute for Radioastronomy, Auf dem Huegel 69, D-53121 Bonn (Germany); Geach, James E., E-mail: padelis@mpifr-bonn.mpg.de, E-mail: jimgeach@physics.mcgill.ca [Department of Physics, McGill University, 3600 rue University, Montreal Quebec, H3A 2T8 (Canada)

2012-10-01T23:59:59.000Z

376

High energy laser beam dump  

DOE Patents [OSTI]

The laser beam dump is positioned in a housing. An absorbing glass plate means is operatively connected to the housing. A heat sync means for extracting heat from the absorbing glass plate means is operatively connected to the housing and operatively connected to the absorbing glass plate means.

Halpin, John (Tracy, CA)

2004-09-14T23:59:59.000Z

377

Relativistic atomic beam spectroscopy II  

SciTech Connect (OSTI)

We are requesting support for a postdoctoral person to participate in H{sup -} studies at Los Alamos. In addition, we are requesting funding for a state-of-the-art YAG laser system that would allow us to obtain data at three times our present rate with improved beam quality.

NONE

1991-12-31T23:59:59.000Z

378

Direct analysis of samples by mass spectrometry: From elements to bio-molecules using laser ablation inductively couple plasma mass spectrometry and laser desorption/ionization mass spectrometry  

SciTech Connect (OSTI)

Mass spectrometric methods that are able to analyze solid samples or biological materials with little or no sample preparation are invaluable to science as well as society. Fundamental research that has discovered experimental and instrumental parameters that inhibit fractionation effects that occur during the quantification of elemental species in solid samples by laser ablation inductively coupled plasma mass spectrometry is described. Research that determines the effectiveness of novel laser desorption/ionization mass spectrometric methods for the molecular analysis of biological tissues at atmospheric pressure and at high spatial resolution is also described. A spatial resolution is achieved that is able to analyze samples at the single cell level.

Perdian, David C.

2009-08-19T23:59:59.000Z

379

ALLSMOG: an APEX Low-redshift Legacy Survey for MOlecular Gas. I - molecular gas scaling relations, and the effect of the CO/H2 conversion factor  

E-Print Network [OSTI]

We present ALLSMOG, the APEX Low-redshift Legacy Survey for MOlecular Gas. ALLSMOG is a survey designed to observe the CO(2-1) emission line with the APEX telescope, in a sample of local galaxies (0.01 conversion factor. We find an increase in the H2/HI mass ratio with stellar mass which closely matches semi-analytic predictions. We find a mean molecular gas fraction for ALLSMOG galaxies of MH2/M* = (0.09 - 0.13),...

Bothwell, M S; Cicone, C; Maiolino, R; Mller, P; Aravena, M; De Breuck, C; Peng, Y; Espada, D; Hodge, J A; Impellizzeri, C M V; Martn, S; Riechers, D; Walter, F

2014-01-01T23:59:59.000Z

380

Molecular Hydrogen in Infrared Cirrus  

E-Print Network [OSTI]

We combine data from our recent FUSE survey of interstellar molecular hydrogen absorption toward 50 high-latitude AGN with COBE-corrected IRAS 100 micron emission maps to study the correlation of infrared cirrus with H2. A plot of the H2 column density vs. IR cirrus intensity shows the same transition in molecular fraction, f_H2, as seen with total hydrogen column density, N_H. This transition is usually attributed to H2 self-shielding, and it suggests that many diffuse cirrus clouds contain H2 in significant fractions, f_H2 = 1-30%. These clouds cover approximately 50% of the northern sky at latitudes b > 30 degrees, at temperature-corrected 100 micron intensities D_100 > 1.5 MJy/sr. The sheetlike cirrus clouds, with hydrogen densities n_H > 30 cm^-3, may be compressed by dynamical processes at the disk-halo interface, and they are conducive to H2 formation on grain surfaces. Exploiting the correlation between N(H2) and 100 micron intensity, we estimate that cirrus clouds at b > 30 contain approximately 3000 M_sun in H2. Extrapolated over the inner Milky Way, the cirrus may contain 10^7 M_sun of H2 and 10^8 M_sun in total gas mass. If elevated to 100 pc, their gravitational potential energy is ~10^53 erg.

Kristen Gillmon; J. Michael Shull

2005-07-25T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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

Nuclear Masses in Astrophysics  

E-Print Network [OSTI]

Among all nuclear ground-state properties, atomic masses are highly specific for each particular combination of N and Z and the data obtained apply to a variety of physics topics. One of the most crucial questions to be addressed in mass spectrometry of unstable radionuclides is the one of understanding the processes of element formation in the Universe. To this end, accurate atomic mass values of a large number of exotic nuclei participating in nucleosynthesis are among the key input data in large-scale reaction network calculations. In this paper, a review on the latest achievements in mass spectrometry for nuclear astrophysics is given.

Christine Weber; Klaus Blaum; Hendrik Schatz

2008-12-09T23:59:59.000Z

382

EMSL - Mass Spectrometer  

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

mass-spectrometer en Physical Properties of Ambient and Laboratory-Generated Secondary Organic Aerosol. http:www.emsl.pnl.govemslwebpublicationsphysical-properties-ambient-and...

383

Electron Beam--21st Century Food Technology  

E-Print Network [OSTI]

This publication explains electron beam irradiation technology to consumers, industry professionals and government officials. Electron beam irradiation is a method of treating food and other products for pathogens that might jeopardize food safety....

Vestal, Andy

2003-03-07T23:59:59.000Z

384

Autogenerator of beams of charged particles  

DOE Patents [OSTI]

An autogenerating apparatus provides secondary intense relativistic current beam pulses in response to an injected beam pulse. One or more electromagnetic energy storage devices are provided in conjunction with gaps along a beam propagation path for the injected beam pulse. For injected beam pulses which are no longer than double the transit time of electromagnetic waves within the storage devices (which may be resonant cavities), distinct secondary beam pulses are generated by each of the energy storage devices. The beam propagation path, together with the one or more gaps provided therein, operates as a pulse forming transmission line cavity, in which the separate cavities associated with the gaps provide delays for electromagnetic waves generated at the gaps. After doubly traversing the cavity, the electromagnetic waves cause the gap to generate the secondary beam pulses, which are thus delayed by a time interval equal to the double transit time for the induced wave within the cavity.

Adler, R.J.; Mazarakis, M.G.; Miller, R.M.; Shope, S.L.; Smith, D.L.

1983-10-31T23:59:59.000Z

385

Fusion Reactions Involving Radioactive Beams at GANIL  

Science Journals Connector (OSTI)

......February 2004 research-article Articles Fusion Reactions Involving Radioactive Beams...been used to produce exotic nuclei via fusion evaporation or to study reaction mechanisms...Physics Supplement No. 154, 2004 113 Fusion Reactions Involving Radioactive Beams......

Gilles de France

2004-02-01T23:59:59.000Z

386

Autogenerator of beams of charged particles  

DOE Patents [OSTI]

An autogenerating apparatus provides secondary intense relativistic current beam pulses in response to an injected beam pulse. One or more electromagnetic energy storage devices are provided in conjunction with gaps along a beam propagation path for the injected beam pulse. For injected beam pulses which are no longer than double the transit time of electromagnetic waves within the storage devices (which may be resonant cavities), distinct secondary beam pulses are generated by each of the energy storage devices. The beam propagation path, together with the one or more gaps provided therein, operates as a pulse forming transmission line cavity, in which the separate cavities associated with the gaps provide delays for electromagnetic waves generated at the gaps. After doubly traversing the cavity, the electromagnetic waves cause the gap to generate the secondary beam pulses, which are thus delayed by a time interval equal to the double transit time for the induced wave within the cavity.

Adler, Richard J. (Albuquerque, NM); Mazarakis, Michael G. (Albuquerque, NM); Miller, Robert B. (Albuquerque, NM); Shope, Steven L. (Albuquerque, NM); Smith, David L. (Albuquerque, NM)

1986-01-01T23:59:59.000Z

387

Transport of elliptic intense charged -particle beams  

E-Print Network [OSTI]

The transport theory of high-intensity elliptic charged-particle beams is presented. In particular, the halo formation and beam loss problem associated with the high space charge and small-aperture structure is addressed, ...

Zhou, J. (Jing), 1978-

2006-01-01T23:59:59.000Z

388

Adaptive phase measurements for narrowband squeezed beams  

E-Print Network [OSTI]

We have previously [Phys. Rev. A 65, 043803 (2002)] analyzed adaptive measurements for estimating the continuously varying phase of a coherent beam, and a broadband squeezed beam. A real squeezed beam must have finite photon flux N and hence can be significantly squeezed only over a limited frequency range. In this paper we analyze adaptive phase measurements of this type for a realistic model of a squeezed beam. We show that, provided it is possible to suitably choose the parameters of the beam, a mean-square phase uncertainty scaling as (N/kappa)^{-5/8} is possible, where kappa is the linewidth of the beam resulting from the fluctuating phase. This is an improvement over the (N/kappa)^{-1/2} scaling found previously for coherent beams. In the experimentally realistic case where there is a limit on the maximum squeezing possible, the variance will be reduced below that for coherent beams, though the scaling is unchanged.

Dominic W. Berry; Howard M. Wiseman

2006-03-22T23:59:59.000Z

389

MIS-1 electron-beam ion source  

Science Journals Connector (OSTI)

The Institute of Nuclear Physics (INP) has developed and produced electron-beam multiply charged ion sources. These ion sources give the electron beam its high density in the ionization...3 A/cm2.... They produce...

V. G. Abdulmanov; N. S. Dikansky

2010-12-01T23:59:59.000Z

390

Properties of Molecular Gas in Galaxies in Early and Mid Stage of Interaction: II. Molecular Gas Fraction  

E-Print Network [OSTI]

We have investigated properties of interstellar medium in interacting galaxies in early and mid stages using mapping data of 12CO(J =1-0) and HI. Total gas mass (a sum of atomic and molecular gas mass) in interacting galaxies slightly reduced with large dispersion in the comparison with field galaxies. We found that molecular gas mass is enhanced in interacting galaxies assuming the standard CO-H2 conversion factor, while atomic gas mass is reduced. These results are reinforced by the fact that interacting galaxies have higher molecular gas fraction (fmol), a ratio of the surface density of molecular gas to that of total gas, (0.71 +- 0.15) than isolated galaxies (0.52 +- 0.18) and this indicates that an efficient transition from atomic gas to molecular gas is induced by the interaction. Isolated spiral galaxies show monotonically and gradually increase of fmol along the surface density of total gas. Contrary to isolated galaxies, interacting galaxies show high fmol (>0.8) even at low surface density of total...

Kaneko, Hiroyuki; Iono, Daisuke; Tamura, Yoichi; Tosaki, Tomoka; Nakanishi, Koichiro; Sawada, Tsuyoshi

2014-01-01T23:59:59.000Z

391

Molecular Outflows from Young Stellar Objects  

E-Print Network [OSTI]

We review some aspects of the bipolar molecular outflow phenomenon. In particular, we compare the morphological properties, energetics and velocity structures of outflows from high and low-mass protostars and investigate to what extent a common source model can explain outflows from sources of very different luminosities. Many flow properties, in particular the CO spatial and velocity structure, are broadly similar across the entire luminosity range, although the evidence for jet-entrainment is still less clear cut in massive flows than in low-mass systems. We use the correlation of flow momentum deposition rate with source luminosity to estimate the ratio f of mass ejection to mass accretion rate. From this analysis, it appears that a common driving mechanism could operate across the entire luminosity range. However, we stress that for the high-mass YSOs, the detailed physics of this mechanism and how the ejected wind/jet entrains ambient material remain to be addressed. We also briefly consider the alternative possibility that high-mass outflows can be explained by the recently proposed circulation models, and discuss several shortcomings of those models. Finally, we survey the current evidence on the nature of the shocks driven by YSOs during their pre-main-sequence evolution.

John Richer; Debra Shepherd; Sylvie Cabrit; Rafael Bachiller; Ed Churchwell

1999-04-08T23:59:59.000Z

392

Laser Telecommunication timeLaser beam  

E-Print Network [OSTI]

Laser Telecommunication Experiment Laser time Laser beam intensity timeLaser beam Laser battery Laser connected to a circuit without a modulator. Bottom graph illustrates what happen when a modulating signal is superimposed to the DC voltage driving the laser Laser beam intensity DC Input voltage DC

La Rosa, Andres H.

393

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

394

Cyclotrons for the production of radioactive beams  

SciTech Connect (OSTI)

This paper describes the characteristics and design choices for modern cyclotrons. Cyclotrons can be used in 3 areas in the radioactive beam field: the production of high energy heavy ion beams for use in fragmentation, the spallation of targets with high energy protons, and the acceleration of radioactive beams from low energy to the MeV/u range. 16 refs., 6 figs.

Clark, D.J.

1990-01-01T23:59:59.000Z

395

Beam Dynamics and Instabilities in MEIC Design  

SciTech Connect (OSTI)

In this paper, we study the narrow and broadband impedance calculations and various instabilities generated by single and multiple bunches. We study the physical phenomena such as intra-beam scattering, touschek scattering, beam-gas scattering, ion trapping and fast beam-ion instability, etc. Details will be discussed in the paper.

S. Ahmed, G.A. Krafft, B.C. Yunn

2011-03-01T23:59:59.000Z

396

Gaussian beams in inhomogeneous anisotropic layered structures  

E-Print Network [OSTI]

Gaussian beams in inhomogeneous anisotropic layered structures Vlastislav Cerven´y 1 ) and Ivan@ig.cas.cz. Summary Gaussian beams concentrated close to rays of high-frequency seismic body waves prop- agating in an inhomogeneous anisotropic layered structure are studied. The amplitude profiles of the Gaussian beam along

Cerveny, Vlastislav

397

A Generalized Vlasov Theory for Composite Beams  

E-Print Network [OSTI]

A Generalized Vlasov Theory for Composite Beams Wenbin Yu, Department of Mechanical and Aerospace-0150 Abstract A generalized Vlasov theory for composite beams with arbitrary geometric and material sectional properties is developed based on the variational asymptotic beam sectional analysis. Instead of invoking ad

Yu, Wenbin

398

Stability design of long precast concrete beams  

E-Print Network [OSTI]

Stability design of long precast concrete beams T. J. Stratford, BA, MEng, C. J. Burgoyne BA, MSc needed for design engineers to check the stability of precast concrete beams when simply supported loads can be determined and how estimates can be made of the eect of imperfections both in the beam

Burgoyne, Chris

399

Lateral stability of long precast concrete beams  

E-Print Network [OSTI]

Lateral stability of long precast concrete beams T. J. Stratford, BA, BEng, and C. J. Burgoyne, BA, MSc, CEng, MICE & Modern precast concrete bridge beams are becoming increasingly long and slender, making them more susceptible to buckling failure. This paper shows that once the beam is positioned

Burgoyne, Chris

400

Evaporation model for beam based additive manufacturing using free surface lattice Boltzmann methods  

Science Journals Connector (OSTI)

Evaporation plays an important role in many technical applications including beam-based additive manufacturing processes, such as selective electron beam or selective laser melting (SEBM/SLM). In this paper, we describe an evaporation model which we employ within the framework of a two-dimensional free surface lattice Boltzmann method. With this method, we solve the hydrodynamics as well as thermodynamics of the molten material taking into account the mass and energy losses due to evaporation and the recoil pressure acting on the melt pool. Validation of the numerical model is performed by measuring maximum melt depths and evaporative losses in samples of pure titanium and Ti6Al4V molten by an electron beam. Finally, the model is applied to create processing maps for an SEBM process. The results predict that the penetration depth of the electron beam, which is a function of the acceleration voltage, has a significant influence on evaporation effects.

Alexander Klassen; Thorsten Scharowsky; Carolin Krner

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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

Annular Vortex Generation for Inertial Fusion Energy Beam-Line Protection  

SciTech Connect (OSTI)

The use of swirling annular vortex flow inside beam entrance tubes can protect beam-line structural materials in chambers for heavy-ion inertial fusion energy (IFE) applications. An annular wall jet, or vortex tube, is generated by injecting liquid tangent to the inner surface of a tube wall with both axially and azimuthally directed velocity components. A layer of liquid then lines the beam tube wall, which may improve the effectiveness of neutron shielding, and condenses and removes vaporized coolant that may enter the beam tubes. Vortex tubes have been constructed and tested with a thickness of three-tenths the pipe radius. Analysis of the flow is given, along with experimental examples of vortex tube fluid mechanics and an estimate of the layer thickness, based on simple mass conservation considerations.

Pemberton, Steven J.; Abbott, Ryan P.; Peterson, Per F. [University of California (United States)

2003-05-15T23:59:59.000Z

402

Electron Trapping by Molecular Vibration  

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

Electron Trapping by Molecular Vibration Electron Trapping by Molecular Vibration Print Wednesday, 27 April 2005 00:00 In photoelectron spectroscopy experiments performed at the...

403

Elbow mass flow meter  

DOE Patents [OSTI]

The present invention includes a combination of an elbow pressure drop generator and a shunt-type mass flow sensor for providing an output which gives the mass flow rate of a gas that is nearly independent of the density of the gas. For air, the output is also approximately independent of humidity. 3 figs.

McFarland, A.R.; Rodgers, J.C.; Ortiz, C.A.; Nelson, D.C.

1994-08-16T23:59:59.000Z

404

The Origins of Mass  

SciTech Connect (OSTI)

The Higgs boson was discovered in July of 2012 and is generally understood to be the origin of mass. While those statements are true, they are incomplete. It turns out that the Higgs boson is responsible for only about 2% of the mass of ordinary matter. In this dramatic new video, Dr. Don Lincoln of Fermilab tells us the rest of the story.

Lincoln, Don

2014-07-30T23:59:59.000Z

405

Gas Chromatography -Mass Spectrometry  

E-Print Network [OSTI]

GCMS - 1 Gas Chromatography - Mass Spectrometry GC-MS ANALYSIS OF ETHANOL AND BENZENE IN GASOLINE Last updated: June 17, 2014 #12;GCMS - 2 Gas Chromatography - Mass Spectrometry GC-MS ANALYSIS). The goal of this experiment is to separate the components in a sample of gasoline using Gas Chromatography

Nizkorodov, Sergey

406

Molecular heat pump  

E-Print Network [OSTI]

We propose a novel molecular device that pumps heat against a thermal gradient. The system consists of a molecular element connecting two thermal reservoirs that are characterized by different spectral properties. The pumping action is achieved by applying an external force that periodically modulates molecular levels. This modulation affects periodic oscillations of the internal temperature of the molecule and the strength of its coupling to each reservoir resulting in a net heat flow in the desired direction. The heat flow is examined in the slow and fast modulation limits and for different modulation waveforms, thus making it possible to optimize the device performance.

Dvira Segal; Abraham Nitzan

2005-10-11T23:59:59.000Z

407

W Transverse Mass  

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

Some Data Analysis Some Data Analysis The Tevatron produces millions of collisions each second in CDF and DZero. The detectors have hardware triggers to decide if a collision is "interesting," that is it contains a candidate event for any one of a number studies. Our dataset contains 48,844 candidate events for a W mass study. There are other datasets to study Z mass, top and b quarks, QCD, etc. Why don't all the W decays give exactly the same mass? Are all these candidates really Ws? What if we chose only some of these data. How would our choice effect the value of the transverse mass? Work with your classmates. Test the data to see what you can learn. Help with data analysis. Record the best estimate of the W transverse mass from your data analysis. Explain which data you used and why. Check with your classmates and explain any differences between your estimate and theirs.

408

Electron beam diagnostic for space charge measurement of an ion beam  

SciTech Connect (OSTI)

A non-perturbing electron beam diagnostic system for measuring the charge distribution of an ion beam is developed for Heavy Ion Fusion (HIF) beam physics studies. Conventional diagnostics require temporary insertion of sensors into the beam, but such diagnostics stop the beam, or significantly alter its properties. In this diagnostic a low energy, low current electron beam is swept transversely across the ion beam; the measured electron beam deflection is used to infer the charge density profile of the ion beam. The initial application of this diagnostic is to the Neutralized Transport Experiment (NTX), which is exploring the physics of space-charge-dominated beam focusing onto a small spot using a neutralizing plasma. Design and development of this diagnostic and performance with the NTX ion beamline is presented.

Roy, Prabir K.; Yu, Simon S.; Henestroza, Enrique; Eylon, Shmuel; Shuman, Derek B.; Ludvig, Jozsef; Bieniosek, Frank M.; Waldron, William L.; Greenway, Wayne G.; Vanecek, David L.; Hannink, Ryan; Amezcua, Monserrat

2004-09-25T23:59:59.000Z

409

Apparatus and method of determining molecular weight of large molecules  

DOE Patents [OSTI]

A mass spectrometer determines the mass of multiply charged high molecular weight molecules. This spectrometer utilizes an ion detector which is capable of simultaneously measuring the charge z and transit time of a single ion as it passes through the detector. From this transit time, the velocity of the single ion may then be derived, thus providing the mass-to-charge ratio m/z for a single ion which has been accelerated through a known potential. Given z and m/z, the mass m of the single ion can then be calculated. Electrospray ions with masses in excess of 1 MDa and charge numbers greater than 425 e{sup {minus}} are readily detected. The on-axis single ion detection configuration enables a duty cycle of nearly 100% and extends the practical application of electrospray mass spectrometry to the analysis of very large molecules with relatively inexpensive instrumentation. 14 figs.

Fuerstenau, S.; Benner, W.H.; Madden, N.M.; Searles, W.

1998-06-23T23:59:59.000Z

410

Apparatus and method of determining molecular weight of large molecules  

DOE Patents [OSTI]

A mass spectrometer determines the mass of multiply charged high molecular weight molecules. This spectrometer utilizes an ion detector which is capable of simultaneously measuring the charge z and transit time of a single ion as it passes through the detector. From this transit time, the velocity of the single ion may then be derived, thus providing the mass-to-charge ratio m/z for a single ion which has been accelerated through a known potential. Given z and m/z, the mass m of the single ion can then be calculated. Electrospray ions with masses in excess of 1 MDa and charge numbers greater than 425 e.sup.- are readily detected. The on-axis single ion detection configuration enables a duty cycle of nearly 100% and extends the practical application of electrospray mass spectrometry to the analysis of very large molecules with relatively inexpensive instrumentation.

Fuerstenau, Stephen (Montrose, CA); Benner, W. Henry (Danville, CA); Madden, Norman (Livermore, CA); Searles, William (Fremont, CA)

1998-01-01T23:59:59.000Z

411

Beam Time Allocation Committee (BAC)  

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

Time Allocation Committee (BAC) Time Allocation Committee (BAC) Charter Purpose: Allocates general user beam time by instrument to promote diverse and high- impact science and a broad-based user community to meet DOE and NSSD goals. Participants: BAC Chair (appointed by NSSD Director), Instrument Group Leaders, User Office Schedule: Tied to proposal calls - expected to meet at least 2 times/year with meetings scheduled about 6 weeks after the proposal call has closed and at least 1 month prior to scheduled operations. Process: 1. Instrument Group Leaders (with group members): a. Confirm feasibility (equipment requirements and instrument capabilities) and safe operations b. Review amount of beam time requested and adjust as needed with consideration for instrument and sample environment availability.

412

Center for Beam Physics, 1993  

SciTech Connect (OSTI)

The Center for Beam Physics is a multi-disciplinary research and development unit in the Accelerator and Fusion Research Division at Lawrence Berkeley Laboratory. At the heart of the Center`s mission is the fundamental quest for mechanisms of acceleration, radiation and focusing of energy. Dedicated to exploring the frontiers of the physics of (and with) particle and photon beams, its primary mission is to promote the science and technology of the production, manipulation, storage and control systems of charged particles and photons. The Center serves this mission via conceptual studies, theoretical and experimental research, design and development, institutional project involvement, external collaborations, association with industry and technology transfer. This roster provides a glimpse at the scientists, engineers, technical support, students, and administrative staff that make up this team and a flavor of their multifaceted activities during 1993.

Not Available

1994-05-01T23:59:59.000Z

413

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. 5 figures.

Tsuo, Y.S.

1991-08-20T23:59:59.000Z

414

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

415

Neutron beam testing of triblades  

SciTech Connect (OSTI)

Four IBM Triblades were tested in the Irradiation of Chips and Electronics facility at the Los Alamos Neutron Science Center. Triblades include two dual-core Opteron processors and four PowerXCell 8i (Cell) processors. The Triblades were tested in their field configuration while running different applications, with the beam aimed at the Cell processor or the Opteron running the application. Testing focused on the Cell processors, which were tested while running five different applications and an idle condition. While neither application nor Triblade was statistically important in predicting the hazard rate, the hazard rate when the beam was aimed at the Opterons was significantly higher than when it was aimed at the Cell processors. In addition, four Cell blades (one in each Triblade) suffered voltage shorts, leading to their inoperability. The hardware tested is the same as that in the Roadrunner supercomputer.

Michalak, Sarah E [Los Alamos National Laboratory; Du Bois, Andrew J [Los Alamos National Laboratory; Storlie, Curtis B [Los Alamos National Laboratory; Rust, William N [Los Alamos National Laboratory; Du Bois, David H [Los Alamos National Laboratory; Modl, David G [Los Alamos National Laboratory; Quinn, Heather M [Los Alamos National Laboratory; Blanchard, Sean P [Los Alamos National Laboratory; Manuzzato, Andrea [UNIV DEGLI STUDI DI PADOVA ITALY

2010-12-16T23:59:59.000Z

416

VAV Reheat Versus Active Chilled Beams and DOAS  

E-Print Network [OSTI]

Andrey. Dont Turn Active Beams Into Expensive Diffusers,added costs of the piping and beams for ACBs are simply too1. Simmonds, Peter. To Beam or not To Beam? , Engineered

Stein, Jeff; Taylor, Steven

2013-01-01T23:59:59.000Z

417

National Centre for Biological Sciences Mass Spectrometry Facility  

E-Print Network [OSTI]

: Sample Information Number of samples: Sample ID: Concentration: Solubility: Expected mass (Da): Molecular: Protein Peptide Lipid Nucleic acid Others (specify) Analysis Requirement ESI MS, low resolution ESI MS, high resolution LC-ESI MS LC-ESI MS/MS Others (specify) Signature of research supervisor: Signature

Bhalla, Upinder S.

418

Introduction The Sun is a mass of incandescent gas  

E-Print Network [OSTI]

Chapter 1 Introduction The Sun is a mass of incandescent gas A gigantic nuclear furnace Building that our bodies contain atoms that, like most elements and their isotopes in the Solar System, were part of the molecular cloud from which the Solar System condensed, and were trapped in primitive

Nittler, Larry R.

419

Electron beam irradiation of dimethyl-(acetylacetonate) gold(III) adsorbed onto solid substrates  

SciTech Connect (OSTI)

Electron beam induced deposition of organometallic precursors has emerged as an effective and versatile method for creating two-dimensional and three-dimensional metal-containing nanostructures. However, to improve the properties and optimize the chemical composition of nanostructures deposited in this way, the electron stimulated decomposition of the organometallic precursors must be better understood. To address this issue, we have employed an ultrahigh vacuum-surface science approach to study the electron induced reactions of dimethyl-(acetylacetonate) gold(III) [Au{sup III}(acac)Me{sub 2}] adsorbed onto solid substrates. Using thin molecular films adsorbed onto cooled substrates, surface reactions, reaction kinetics, and gas phase products were studied in the incident energy regime between 40 and 1500 eV using a combination of x-ray photoelectron spectroscopy (XPS), reflection absorption infrared spectroscopy (RAIRS), and mass spectrometry (MS). XPS and RAIRS data indicate that electron irradiation of Au{sup III}(acac)Me{sub 2} is accompanied by the reduction in Au{sup III} to a metallic Au{sup 0} species embedded in a dehydrogenated carbon matrix, while MS reveals the concomitant evolution of methane, ethane, carbon monoxide, and hydrogen. The electron stimulated decomposition of Au{sup III}(acac)Me{sub 2} is first-order with respect to the surface coverage of the organometallic precursor, and exhibits a rate constant that is proportional to the electron flux. At an incident electron energy of 520 eV, the total reaction cross section was {approx_equal}3.6x10{sup -16} cm{sup 2}. As a function of the incident electron energy, the maximum deposition yield was observed at {approx_equal}175 eV. The structure of discrete Au-containing deposits formed at room temperature by rastering an electron beam across a highly ordered pyrolytic graphite substrate in the presence of a constant partial pressure of Au{sup III}(acac)Me{sub 2} was also investigated by atomic force microscopy.

Wnuk, Joshua D.; Gorham, Justin M.; Rosenberg, Samantha G.; Fairbrother, D. Howard [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Dorp, Willem F. van [Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers, State University of New Jersey, Piscataway, New Jersey 08854-8019 (United States); Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628CJ Delft (Netherlands); Madey, Theodore E. [Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers, State University of New Jersey, Piscataway, New Jersey 08854-8019 (United States); Hagen, Cornelis W. [Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628CJ Delft (Netherlands)

2010-03-15T23:59:59.000Z

420

W-Band Sheet Beam Klystron Design  

SciTech Connect (OSTI)

Sheet beam devices provide important advantages for very high power, narrow bandwidth RF sources like accelerator klystrons [1]. Reduced current density and increased surface area result in increased power capabi1ity, reduced magnetic fields for focusing and reduced cathode loading. These advantages are offset by increased complexity, beam formation and transport issues and potential for mode competition in the ovennoded cavities and drift tube. This paper will describe the design issues encountered in developing a 100 kW peak and 2 kW average power sheet beam k1ystron at W-band including beam formation, beam transport, circuit design, circuit fabrication and mode competition.

Scheitrum, G.; Caryotakis, G.; Burke, A.; Jensen, A.; Jongewaard, E.a Krasnykh, A.; Neubauer, M.; Phillips, R.; Rauenbuehler, K.; /SLAC

2011-11-11T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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.


421

Carbon Fiber Damage in Accelerator Beam  

E-Print Network [OSTI]

Carbon fibers are commonly used as moving targets in Beam Wire Scanners. Because of their thermomechanical properties they are very resistant to particle beams. Their strength deteriorates with time due to radiation damage and low-cycle thermal fatigue. In case of high intensity beams this process can accelerate and in extreme cases the fiber is damaged during a single scan. In this work a model describing the fiber temperature, thermionic emission and sublimation is discussed. Results are compared with fiber damage test performed on SPS beam in November 2008. In conclusions the limits of Wire Scanner operation on high intensity beams are drawn.

Sapinski, M; Guerrero, A; Koopman, J; Mtral, E

2009-01-01T23:59:59.000Z

422

Scattering apodizer for laser beams  

DOE Patents [OSTI]

A method is disclosed for apodizing a laser beam to smooth out the production of diffraction peaks due to optical discontinuities in the path of the laser beam, such method comprising introduction of a pattern of scattering elements for reducing the peak intensity in the region of such optical discontinuities, such pattern having smoothly tapering boundaries in which the distribution density of the scattering elements is tapered gradually to produce small gradients in the distribution density, such pattern of scattering elements being effective to reduce and smooth out the diffraction effects which would otherwise be produced. The apodizer pattern may be produced by selectively blasting a surface of a transparent member with fine abrasive particles to produce a multitude of minute pits. In one embodiment, a scattering apodizer pattern is employed to overcome diffraction patterns in a multiple element crystal array for harmonic conversion of a laser beam. The interstices and the supporting grid between the crystal elements are obscured by the gradually tapered apodizer pattern of scattering elements.

Summers, Mark A. (Livermore, CA); Hagen, Wilhelm F. (Livermore, CA); Boyd, Robert D. (Livermore, CA)

1985-01-01T23:59:59.000Z

423

Scattering apodizer for laser beams  

DOE Patents [OSTI]

A method is disclosed for apodizing a laser beam to smooth out the production of diffraction peaks due to optical discontinuities in the path of the laser beam, such method comprising introduction of a pattern of scattering elements for reducing the peak intensity in the region of such optical discontinuities, such pattern having smoothly tapering boundaries in which the distribution density of the scattering elements is tapered gradually to produce small gradients in the distribution density, such pattern of scattering elements being effective to reduce and smooth out the diffraction effects which would otherwise be produced. The apodizer pattern may be produced by selectively blasting a surface of a transparent member with fine abrasive particles to produce a multitude of minute pits. In one embodiment, a scattering apodizer pattern is employed to overcome diffraction patterns in a multiple element crystal array for harmonic conversion of a laser beam. The interstices and the supporting grid between the crystal elements are obscured by the gradually tapered apodizer pattern of scattering elements.

Summers, M.A.; Hagen, W.F.; Boyd, R.D.

1984-01-01T23:59:59.000Z

424

Structural Molecular Biology, SSRL  

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

Biological Small Angle X-ray Scattering Workshop The SSRL Structural Molecular Biology Group hosted a 3-day comprehensive workshop on the use of non-crystalline small-angle...

425

Theory of Molecular Machines. I. Channel Capacity of Molecular Machines  

E-Print Network [OSTI]

Theory of Molecular Machines. I. Channel Capacity of Molecular Machines running title: Channel Capacity of Molecular Machines Thomas D. Schneider version = 5.76 of ccmm.tex 2004 Feb 3 Version 5.67 was submitted 1990 December 5 Schneider, T. D. (1991). Theory of molecular machines. I. Channel capacity

Schneider, Thomas D.

426

Particle beam injector system and method  

DOE Patents [OSTI]

Methods and devices enable coupling of a charged particle beam to a radio frequency quadrupole accelerator. Coupling of the charged particle beam is accomplished, at least in-part, by relying on of sensitivity of the input phase space acceptance of the radio frequency quadrupole to the angle of the input charged particle beam. A first electric field across a beam deflector deflects the particle beam at an angle that is beyond the acceptance angle of the radio frequency quadrupole. By momentarily reversing or reducing the established electric field, a narrow portion of the charged particle beam is deflected at an angle within the acceptance angle of the radio frequency quadrupole. In another configuration, beam is directed at an angle within the acceptance angle of the radio frequency quadrupole by the first electric field and is deflected beyond the acceptance angle of the radio frequency quadrupole due to the second electric field.

Guethlein, Gary

2013-06-18T23:59:59.000Z

427

Paraxial Light Beams with Angular Momentum  

E-Print Network [OSTI]

Fundamental and applied concepts concerning the ability of light beams to carry a certain mechanical angular momentum with respect to the propagation axis are reviewed and discussed. Following issues are included: Historical reference; Angular momentum of a paraxial beam and its constituents; Spin angular momentum and paradoxes associated with it; Orbital angular momentum; Circularly-spiral beams: examples and methods of generation; Orbital angular momentum and the intensity moments; Symmetry breakdown and decomposition of the orbital angular momentum; Mechanical models of the vortex light beams; Mechanical action of the beam angular momentum; Rotational Doppler effect, its manifestation in the image rotation; Spectrum of helical harmonics and associated problems; Non-collinear rotational Doppler effect; Properties of a beam forcedly rotating around its own axis. Research prospects and ways of practical utilization of optical beams with angular momentum.

A. Bekshaev; M. Soskin; M. Vasnetsov

2008-01-15T23:59:59.000Z

428

Evaluation of histone sequence and modifications by electrospray ionization mass spectrometry and tandem mass spectrometry  

SciTech Connect (OSTI)

The histones, together with other specialized proteins and DNA, form the extraordinarily complex structure of chromatin. Electrospray ionization (ESI) permits the promotion of such protein species into the gas phase as intact, multiply charged molecular species. Mass spectrometry (MS), using a linear quadrupole mass filter, permits measurement of the relative molecular mass of these intact species with precision and accuracy. The latter are sufficient to evaluate variations in the primary structure of the histones and the type and extent of the natural and induced multiple covalent modifications. The locations of modifications are revealed by tandem mass spectrometry using tandem linear quadrupole or ion trap instruments on the intact species or the modified peptides derived by selective proteolysis. Experiments in applying this technique to histones from K562, a human-derived cell line, have demonstrated variations in the profile of modification through the normal cell cycle and in the presence of agents that inhibit enzymes responsible for reversal of the modification. The authors are currently testing the hypothesis that ESI-MS will permit the sensitive and selective identification of insult-induced modifications, distinguishing them from natural cell-cycle changes. This will be possible because ESI-MS reveals the full details of the profile of multiple posttranslational modifications of histones.

Edmonds, C.G.; Loo, J.A.; Smith, R.D.; Fuciarelli, A.F.; Thrall, B.D.; Morris, J.E.; Springer, D.L. (Pacific Northwest Lab., Richland, WA (United States))

1993-01-01T23:59:59.000Z

429

ALMA RESOLVES 30 DORADUS: SUB-PARSEC MOLECULAR CLOUD STRUCTURE NEAR THE CLOSEST SUPER STAR CLUSTER  

SciTech Connect (OSTI)

We present Atacama Large (sub)Millimeter Array observations of 30 Doradus-the highest resolution view of molecular gas in an extragalactic star formation region to date ({approx}0.4 pc Multiplication-Sign 0.6 pc). The 30Dor-10 cloud north of R136 was mapped in {sup 12}CO 2-1, {sup 13}CO 2-1, C{sup 18}O 2-1, 1.3 mm continuum, the H30{alpha} recombination line, and two H{sub 2}CO 3-2 transitions. Most {sup 12}CO emission is associated with small filaments and clumps ({approx}<1 pc, {approx}10{sup 3} M{sub Sun} at the current resolution). Some clumps are associated with protostars, including ''pillars of creation'' photoablated by intense radiation from R136. Emission from molecular clouds is often analyzed by decomposition into approximately beam-sized clumps. Such clumps in 30 Doradus follow similar trends in size, linewidth, and surface density to Milky Way clumps. The 30 Doradus clumps have somewhat larger linewidths for a given size than predicted by Larson's scaling relation, consistent with pressure confinement. They extend to a higher surface density at a given size and linewidth compared to clouds studied at 10 pc resolution. These trends are also true of clumps in Galactic infrared-dark clouds; higher resolution observations of both environments are required. Consistency of clump masses calculated from dust continuum, CO, and the virial theorem reveals that the CO abundance in 30 Doradus clumps is not significantly different from the Large Magellanic Cloud mean, but the dust abundance may be reduced by {approx}2. There are no strong trends in clump properties with distance from R136; dense clumps are not strongly affected by the external radiation field, but there is a modest trend toward lower dense clump filling fraction deeper in the cloud.

Indebetouw, Remy; Brogan, Crystal; Leroy, Adam; Hunter, Todd; Kepley, Amanda, E-mail: rindebet@nrao.edu, E-mail: cbrogan@nrao.edu, E-mail: aleroy@nrao.edu [National Radio Astronomy Observatory, 520 Edgemont Road Charlottesville, VA 22903 (United States); and others

2013-09-01T23:59:59.000Z

430

Mass of Ca-36  

E-Print Network [OSTI]

PH YS ICA 1. RE VIK W C VO I. UMK 15, 5 UMBER 6 Mass of ~Cat R. E. Tribble, ~ J. D. Cossairt, and R. A. Kenefick Cyclotron Institute and Physics Department, Texas AChM University, College Station, Texas 77843 (Received 14 October 1976) The ' Ca...('He, He)' Ca reaction has been used to provide the first observation of the nuclide ' Ca. The Q value and mass excess were found to be ?57.58~0.04 and ?6.44+0.04 MeV, respectively. The new mass completes four members of the A = 36 isobaric quintet...

Tribble, Robert E.; Cossairt, J. D.; Kenefick, R. A.

1977-01-01T23:59:59.000Z

431

Ultra-high-mass mass spectrometry with charge discrimination using cryogenic detectors  

DOE Patents [OSTI]

An ultra-high-mass time-of-flight mass spectrometer using a cryogenic particle detector as an ion detector with charge discriminating capabilities. Cryogenic detectors have the potential for significantly improving the performance and sensitivity of time-of-flight mass spectrometers, and compared to ion multipliers they exhibit superior sensitivity for high-mass, slow-moving macromolecular ions and can be used as "stop" detectors in time-of-flight applications. In addition, their energy resolving capability can be used to measure the charge state of the ions. Charge discrimination is very valuable in all time-of-flight mass spectrometers. Using a cryogenically-cooled Nb-Al.sub.2 O.sub.3 -Nb superconductor-insulator-superconductor (SIS) tunnel junction (STJ) detector operating at 1.3 K as an ion detector in a time-of-flight mass spectrometer for large biomolecules it was found that the STJ detector has charge discrimination capabilities. Since the cryogenic STJ detector responds to ion energy and does not rely on secondary electron production, as in the conventionally used microchannel plate (MCP) detectors, the cryogenic detector therefore detects large molecular ions with a velocity-independent efficiency approaching 100%.

Frank, Matthias (Berkeley, CA); Mears, Carl A. (Oakland, CA); Labov, Simon E. (Berkeley, CA); Benner, W. Henry (Danville, CA)

1999-01-01T23:59:59.000Z

432

A question of mass  

Science Journals Connector (OSTI)

We present a pedagogical discussion of spontaneous symmetry breaking the Goldstone theorem and the Higgs mechanism. If the Higgs boson is found it might provide an explanation of the origin of mass.

Jeremy Bernstein

2011-01-01T23:59:59.000Z

433

Heavy Hybrid mesons Masses  

E-Print Network [OSTI]

We estimate the ground state masses of the heavy hybrid mesons using a phenomenological QCD-type potential. 0^{- -},1^{- -},0^{- +},1^{- +} and 0^{+ -} J^{PC} states are considered.

F. Iddir; L. Semlala

2006-11-13T23:59:59.000Z

434

MASS POLITICAL MOBILIZATION  

E-Print Network [OSTI]

................................................................................................................................................... MASS POLITICAL MOBILIZATION ................................................................................................................................................... Boix & Stokes: The Oxford Handbook of Comparative Politics Boixandstokes-chap21 Revise Proof page 497 20.4.2007 12:41pm #12;Boix & Stokes: The Oxford Handbook of Comparative Politics Boixandstokes-chap21

435

Masses of Fundamental Particles  

E-Print Network [OSTI]

In the original paper entitled, "Masses of Fundamental Particles"(arXiv:1109.3705v5, 10 Feb 2012), not only the masses of fundamental particles including the weak bosons, Higgs boson, quarks, and leptons, but also the mixing angles of quarks and those of neutrinos are all explained and/or predicted in the unified composite models of quarks and leptons successfully. In this addendum entitled, "Higgs Boson Mass in the Minimal Unified Subquark Model", it is emphasized that the Higgs boson mass is predicted to be about 130Gev in the minimal unified subquark model, which agrees well with the experimental values of 125-126GeV recently found by the ATLAS and CMS Collaborations at the LHC.

Hidezumi Terazawa

2014-06-11T23:59:59.000Z

436

Beam-Beam Simulations for a Single Pass SuperB-Factory  

SciTech Connect (OSTI)

A study of beam-beam collisions for an asymmetric single pass SuperB-Factory is presented [1]. In this scheme an e{sup -} and an e{sup +} beam are first stored and damped in two Damping Rings (DR), then extracted, compressed and focused to the IP. After collision the two beams are re-injected in the DR to be damped and extracted for collision again. The explored beam parameters are similar to those used in the design of the International Linear Collider, except for the beam energies. Flat beams and round beams were compared in the simulations in order to optimize both luminosity performances and beam blowup after collision. With such approach a luminosity of the order of 10{sup 36} cm{sup -2} s{sup -1} can be achieved.

Biagini, M.E.; /Frascati; Raimondi, P.; Seeman, J.; /SLAC; Schulte, D.; /CERN

2007-05-18T23:59:59.000Z

437

Dust Emission from the Perseus Molecular Cloud  

E-Print Network [OSTI]

Using far-infrared emission maps taken by IRAS and Spitzer and a near-infrared extinction map derived from 2MASS data, we have made dust temperature and column density maps of the Perseus molecular cloud. We show that the emission from transiently heated very small grains and the big grain dust emissivity vary as a function of extinction and dust temperature, with higher dust emissivities for colder grains. This variable emissivity can not be explained by temperature gradients along the line of sight or by noise in the emission maps, but is consistent with grain growth in the higher density and lower temperature regions. By accounting for the variations in the dust emissivity and VSG emission, we are able to map the temperature and column density of a nearby molecular cloud with better accuracy than has previously been possible.

S. Schnee; J. Li; A. A. Goodman; A. I. Sargent

2008-05-27T23:59:59.000Z

438

W Transverse Mass  

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

Transverse Mass Histogram Transverse Mass Histogram Data for 49,844 candidate W events are in an Excel spreadsheet with the following data as shown in the table below: A B C D 1 Run No Event No W TMass GeV/c2 Bins 2 55237 19588 68.71732 3 55237 30799 72.19464 Get the data. Sort the data by ascending mass. Be sure to sort all the data in the first three columns! Make a histogram of the data. Rather than graphing the data as individual points, physicists group the data by mass. They consider the full range of the data and divide it into "bins" of equal range size. A histogram is a graph of the number of events in each bin vs. the bin range. They are looking for a peak in the data where most of the masses fall. This will be the value of the mass as detemined by that dataset, and the width of the distribution is a reflection of the errors in the measurements.

439

Optics of electron beam in the Recycler  

SciTech Connect (OSTI)

Electron cooling of 8.9 GeV/c antiprotons in the Recycler ring (Fermilab) requires high current and good quality of the DC electron beam. Electron trajectories of {approx}0.2 A or higher DC electron beam have to be parallel in the cooling section, within {approx}0.2 mrad, making the beam envelope cylindrical. These requirements yielded a specific scheme of the electron transport from a gun to the cooling section, with electrostatic acceleration and deceleration in the Pelletron. Recuperation of the DC beam limits beam losses at as tiny level as {approx}0.001%, setting strict requirements on the return electron line to the Pelletron and a collector. To smooth the beam envelope in the cooling section, it has to be linear and known at the transport start. Also, strength of the relevant optic elements has to be measured with good accuracy. Beam-based optic measurements are being carried out and analyzed to get this information. They include beam simulations in the Pelletron, differential optic (beam response) measurements and simulation, beam profile measurements with optical transition radiation, envelope measurements and analysis with orifice scrapers. Current results for the first half-year of commissioning are presented. Although electron cooling is already routinely used for pbar stacking, its efficiency is expected to be improved.

Burov, Alexey V.; Kazakevich, G.; Kroc, T.; Lebedev, V.; Nagaitsev, S.; Prost, L.; Pruss, S.; Shemyakin, A.; Sutherland, M.; Tiunov, M.; Warner, A.; /Fermilab

2005-11-01T23:59:59.000Z

440

Low Emittance Electron Beam Studies  

SciTech Connect (OSTI)

We have studied the properties of a low emittance electron beam produced by laser pulses incident onto an rf gun photocathode. The experiments were carried out at the A0 photoinjector at Fermilab. Such beam studies are necessary for fixing the design of new Linear Colliders as well as for the development of Free Electron Lasers. An overview of the A0 photoinjector is given in Chapter 1. In Chapter 2 we describe the A0 photoinjector laser system. A stable laser system is imperative for reliable photoinjector operation. After the recent upgrade, we have been able to reach a new level of stability in the pulse-to-pulse fluctuations of the pulse amplitude, and of the temporal and transverse profiles. In Chapter 3 we present a study of transverse emittance versus the shape of the photo-cathode drive-laser pulse. For that purpose a special temporal profile laser shaping device called a pulse-stacker was developed. In Chapter 4 we discuss longitudinal beam dynamics studies using a two macro-particle bunch; this technique is helpful in analyzing pulse compression in the magnetic chicane, as well as velocity bunching effects in the rf-gun and the 9-cell accelerating cavity. In Chapter 5 we introduce a proposal for laser acceleration of electrons. We have developed a laser functioning on the TEM*{sub 01} mode, a mode with a longitudinal electric field component which is suitable for such a process. Using this technique at energies above 40 MeV, one would be able to observe laser-based acceleration.

Tikhoplav, Rodion; /Rochester U.; ,

2006-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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.


441

Radiation and Background Levels in a CLIC Detector due to Beam-Beam Effects Optimisation of Detector Geometries and Technologies  

E-Print Network [OSTI]

The high charge density---due to small beam sizes---and the high energy of the proposed CLIC concept for a linear electron--positron collider with a centre-of-mass energy of up to 3~TeV lead to the production of a large number of particles through beam-beam interactions at the interaction point during every bunch crossing (BX). A large fraction of these particles safely leaves the detector. A still significant amount of energy will be deposited in the forward region nonetheless, which will produce secondary particles able to cause background in the detector. Furthermore, some particles will be created with large polar angles and directly cause background in the tracking detectors and calorimeters. The main sources of background in the detector, either directly or indirectly, are the incoherent $mathrm{e}^{+}mathrm{e}^{-}$ pairs and the particles from $gammagamma ightarrow$ hadron events. The background and radiation levels in the detector have to be estimated, to study if a detector is feasible, that can han...

Sailer, Andr; Lohse, Thomas

2013-01-10T23:59:59.000Z

442

Protective laser beam viewing device  

DOE Patents [OSTI]

A protective laser beam viewing system or device including a camera selectively sensitive to laser light wavelengths and a viewing screen receiving images from the laser sensitive camera. According to a preferred embodiment of the invention, the camera is worn on the head of the user or incorporated into a goggle-type viewing display so that it is always aimed at the area of viewing interest to the user and the viewing screen is incorporated into a video display worn as goggles over the eyes of the user.

Neil, George R.; Jordan, Kevin Carl

2012-12-18T23:59:59.000Z

443

Ramsey Experiments Using Neutron Beams  

Science Journals Connector (OSTI)

Abstract Ramsey's technique of separated oscillatory fields adapted to cold neutron beams is a very sensitive method to probe for spin- dependent interactions of neutrons with magnetic and pseudomagnetic fields. In the last couple of years several distinctive experiments using this technique have been performed, e.g. to determine the incoherent neutron scattering length of the deuteron, to perform polarized neutron imaging of magnetic fields and samples, and lately, to search for new light spin-1 bosons. Here, some of these results are reviewed and possible future measurements with respect to a pulsed neutron source are presented.

Florian M. Piegsa

2014-01-01T23:59:59.000Z

444

Proton beam therapy control system  

DOE Patents [OSTI]

A tiered communications architecture for managing network traffic in a distributed system. Communication between client or control computers and a plurality of hardware devices is administered by agent and monitor devices whose activities are coordinated to reduce the number of open channels or sockets. The communications architecture also improves the transparency and scalability of the distributed system by reducing network mapping dependence. The architecture is desirably implemented in a proton beam therapy system to provide flexible security policies which improve patent safety and facilitate system maintenance and development.

Baumann, Michael A. (Riverside, CA); Beloussov, Alexandre V. (Bernardino, CA); Bakir, Julide (Alta Loma, CA); Armon, Deganit (Redlands, CA); Olsen, Howard B. (Colton, CA); Salem, Dana (Riverside, CA)

2008-07-08T23:59:59.000Z

445

Proton beam therapy control system  

DOE Patents [OSTI]

A tiered communications architecture for managing network traffic in a distributed system. Communication between client or control computers and a plurality of hardware devices is administered by agent and monitor devices whose activities are coordinated to reduce the number of open channels or sockets. The communications architecture also improves the transparency and scalability of the distributed system by reducing network mapping dependence. The architecture is desirably implemented in a proton beam therapy system to provide flexible security policies which improve patent safety and facilitate system maintenance and development.

Baumann, Michael A. (Riverside, CA); Beloussov, Alexandre V. (San Bernardino, CA); Bakir, Julide (Alta Loma, CA); Armon, Deganit (Longmeadow, MA); Olsen, Howard B. (Irvine, CA); Salem, Dana (Riverside, CA)

2010-09-21T23:59:59.000Z

446

Proton beam therapy control system  

DOE Patents [OSTI]

A tiered communications architecture for managing network traffic in a distributed system. Communication between client or control computers and a plurality of hardware devices is administered by agent and monitor devices whose activities are coordinated to reduce the number of open channels or sockets. The communications architecture also improves the transparency and scalability of the distributed system by reducing network mapping dependence. The architecture is desirably implemented in a proton beam therapy system to provide flexible security policies which improve patent safety and facilitate system maintenance and development.

Baumann, Michael A; Beloussov, Alexandre V; Bakir, Julide; Armon, Deganit; Olsen, Howard B; Salem, Dana

2013-06-25T23:59:59.000Z

447

Ion-assisted etching and profile development of silicon in molecular chlorine  

E-Print Network [OSTI]

Ion-assisted etching and profile development of silicon in molecular chlorine Joshua A. Levinson and Eric S. G. Shaqfeha) Department of Chemical Engineering, Stanford University, Stanford, California Laboratory, Livermore, California 94550 Received 2 October 1996; accepted 14 March 1997 An ion beam etching

Shaqfeh, Eric

448

Rapid scanning mass spectrometer  

SciTech Connect (OSTI)

Mass spectrometers and residual gas analyzers (RGA) are used in a variety of applications for analysis of volatile and semi-volatile materials. Analysis is performed by detecting fragments of gas molecules, based on their mass to charge ratio, which are generated in the mass spectrometer. When used as a detector for a gas chromatograph, they function as a means to quantitatively identify isolated volatile species which have been separated from other species via the gas chromatograph. Vacuum Technology, Inc., (VTI) produces a magnetic sector mass spectrometer/RGA which is used in many industrial and laboratory environments. In order to increase the utility of this instrument, it is desirable to increase the mass scanning speed, thereby increasing the number of applications for which it is suited. This project performed the following three upgrades on the computer interface. (1) A new electrometer was designed and built to process the signal from the detector. This new electrometer is more sensitive, over 10 times faster, and over 100 times more stable than the electrometer it will replace. (2) The controller EPROM was reprogrammed with new firmware. This firmware acts as an operating system for the interface and is used to shuttle communications between the PC and the AEROVAC mass spectrometer. (3) The voltage regulator which causes the ion selector voltage to ramp to allow ions of selected mass to be sequentially detected was redesigned and prototyped. The redesigned voltage regulator can be ramped up or down more than 100 times faster than the existing regulator. These changes were incorporated into a prototype unit and preliminary performance testing conducted. Results indicated that scanning speed was significantly increased over the unmodified version.

Leckey, J.H. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States); Boeckmann, M.D. [Vacuum Technology, Inc., Oak Ridge, TN (United States)

1996-11-25T23:59:59.000Z

449

Radiation beam calorimetric power measurement system  

DOE Patents [OSTI]

A radiation beam calorimetric power measurement system for measuring the average power of a beam such as a laser beam, including a calorimeter configured to operate over a wide range of coolant flow rates and being cooled by continuously flowing coolant for absorbing light from a laser beam to convert the laser beam energy into heat. The system further includes a flow meter for measuring the coolant flow in the calorimeter and a pair of thermistors for measuring the temperature difference between the coolant inputs and outputs to the calorimeter. The system also includes a microprocessor for processing the measured coolant flow rate and the measured temperature difference to determine the average power of the laser beam.

Baker, John (Livermore, CA); Collins, Leland F. (Pleasanton, CA); Kuklo, Thomas C. (Ripon, CA); Micali, James V. (Dublin, CA)

1992-01-01T23:59:59.000Z

450

Scalar optical beams with helical symmetry  

Science Journals Connector (OSTI)

Using a nonorthogonal helical coordinate system, we obtain exact free-space solutions for both the Helmholtz and paraxial Helmholtz equations. At optical frequencies the helical Helmholtz solutions can be interpreted as helical beams characterized by a constant pitch angle and beam radius. These solutions are shown to be generalizations of the family of scalar nondiffracting beams known as Bessel beams. They are similar to Bessel beams in some ways, such as an invariant intensity distribution profile in any plane normal to their axis of propagation, but have a nonconstant order. The paraxial helical Helmholtz equation is cast into two different forms, one assuming propagation along the helical axis and one assuming propagation along the original cylindrical axis. The first is solved using a paraxial form of the above helical beam family while a solution of the second form is a helical Gaussian.

P. L. Overfelt

1992-09-15T23:59:59.000Z

451

Rippled beam free electron laser amplifier  

DOE Patents [OSTI]

A free electron laser amplifier provides a scalloping annular electron beam that interacts with the axial electric field of a TM.sub.0n mode. A waveguide defines an axial centerline and, a solenoid arranged about the waveguide produces an axial constant magnetic field within the waveguide. An electron beam source outputs a annular electron beam that interacts with the axial magnetic field to have an equilibrium radius and a ripple radius component having a variable radius with a ripple period along the axial centerline. An rf source outputs an axial electric field that propagates within the waveguide coaxial with the electron beam and has a radial mode that interacts at the electron beam at the equilibrium radius component of the electron beam.

Carlsten, Bruce E. (Los Alamos, NM)

1999-01-01T23:59:59.000Z

452

Composite multi-vortex diffraction-free beams and van Hove singularities in honeycomb lattices  

E-Print Network [OSTI]

We find diffraction-free beams for graphene and MoS$_2$-type honeycomb optical lattices. The resulting composite solutions have the form of multi-vortices, with spinor topological charges ($n$, $n\\pm1$). Exact solutions for the spinor components are obtained in the Dirac limit. The effects of the valley degree of freedom and the mass are analyzed. Passing through the van-Hove singularity the topological structure of the solutions is modified. Exactly at the singularity the diffraction-free beams take the form of strongly localized one-dimensional stripes.

Paltoglou, Vassilis; Efremidis, Nikolaos K

2015-01-01T23:59:59.000Z

453

Plasma-beam interaction in a wiggler  

Science Journals Connector (OSTI)

The possibility of obtaining self-bunching of the beam, emission of coherent radiation and strong electrostatic fields in a plasma loaded free electron laser, is studied by means of a set of nonlinear self-consistent equations deduced from the Maxwell equations, the fluid plasma model, and the relativistic equations of motion for the electrons of the beam in the limit of plasma density much larger than the beam density.

V. Petrillo; A. Serbeto; C. Maroli; R. Parrella; R. Bonifacio

1995-06-01T23:59:59.000Z

454

Coherence delay augmented laser beam homogenizer  

DOE Patents [OSTI]

The geometrical restrictions on a laser beam homogenizer are relaxed by ug a coherence delay line to separate a coherent input beam into several components each having a path length difference equal to a multiple of the coherence length with respect to the other components. The components recombine incoherently at the output of the homogenizer, and the resultant beam has a more uniform spatial intensity suitable for microlithography and laser pantogography. Also disclosed is a variable aperture homogenizer, and a liquid filled homogenizer.

Rasmussen, P.; Bernhardt, A.

1993-06-29T23:59:59.000Z

455

Electroweak Tests at Beta-beams  

E-Print Network [OSTI]

We explore the possibility of measuring the Weinberg angle from (anti)neutrino-electron scattering using low energy beta beams, a method that produces single flavour neutrino beams from the beta-decay of boosted radioactive ions. We study how the sensitivity of a possible measurement depends on the intensity of the ion beam and on a combination of different Lorentz boosts of the ions.

A. B. Balantekin; J. H. de Jesus; C. Volpe

2005-12-22T23:59:59.000Z

456

Halpha with Heating by Particle Beams  

E-Print Network [OSTI]

Using 1D NLTE radiative hydrodynamics we model the influence of the particle beams on the Halpha line profile treating the beam propagation and the atmosphere evolution self-consistently. We focus on the influence of the non-thermal collisional rates and the return current. Based on our results, we propose a diagnostic method for determination of the particle beam presence in the formation regions of the Halpha line.

J. Kasparova; M. Varady; M. Karlicky; P. Heinzel; Z. Moravec

2007-03-30T23:59:59.000Z

457

Coherence delay augmented laser beam homogenizer  

DOE Patents [OSTI]

The geometrical restrictions on a laser beam homogenizer are relaxed by ug a coherence delay line to separate a coherent input beam into several components each having a path length difference equal to a multiple of the coherence length with respect to the other components. The components recombine incoherently at the output of the homogenizer, and the resultant beam has a more uniform spatial intensity suitable for microlithography and laser pantogography. Also disclosed is a variable aperture homogenizer, and a liquid filled homogenizer.

Rasmussen, Paul (Livermore, CA); Bernhardt, Anthony (Berkeley, CA)

1993-01-01T23:59:59.000Z

458

Atomic mass compilation 2012  

SciTech Connect (OSTI)

Atomic mass reflects the total binding energy of all nucleons in an atomic nucleus. Compilations and evaluations of atomic masses and derived quantities, such as neutron or proton separation energies, are indispensable tools for research and applications. In the last decade, the field has evolved rapidly after the advent of new production and measuring techniques for stable and unstable nuclei resulting in substantial ameliorations concerning the body of data and their precision. Here, we present a compilation of atomic masses comprising the data from the evaluation of 2003 as well as the results of new measurements performed. The relevant literature in refereed journals and reports as far as available, was scanned for the period beginning 2003 up to and including April 2012. Overall, 5750 new data points have been collected. Recommended values for the relative atomic masses have been derived and a comparison with the 2003 Atomic Mass Evaluation has been performed. This work has been carried out in collaboration with and as a contribution to the European Nuclear Structure and Decay Data Network of Evaluations.

Pfeiffer, B., E-mail: bpfeiffe@uni-mainz.de [II. Physikalisches Institut, Justus-Liebig-Universitt Gieen, Gieen (Germany); GSI Helmholtzzentrum fr Schwerionenforschung, Darmstadt (Germany); Venkataramaniah, K. [Sri Sathya Sai Institute of Higher Learning, Prasanthinilayam (India)] [Sri Sathya Sai Institute of Higher Learning, Prasanthinilayam (India); Czok, U. [II. Physikalisches Institut, Justus-Liebig-Universitt Gieen, Gieen (Germany)] [II. Physikalisches Institut, Justus-Liebig-Universitt Gieen, Gieen (Germany); Scheidenberger, C. [GSI Helmholtzzentrum fr Schwerionenforschung, Darmstadt (Germany) [GSI Helmholtzzentrum fr Schwerionenforschung, Darmstadt (Germany); II. Physikalisches Institut, Justus-Liebig-Universitt Gieen, Gieen (Germany)

2014-03-15T23:59:59.000Z

459

A MATLAB-based interface for the beam-transport system of an AMS facility  

Science Journals Connector (OSTI)

Abstract In this paper we present a MATLAB code built to model the transport of a charged particle beam through the Accelerator Mass Spectrometry (AMS) facility located at the Centro Nacional de Aceleradores (CNA, Seville, Spain). We determine the beam transport through the optical system using the transfer matrix formalism in two different approaches (ray tracing and the beam-envelope approach) and describe it in terms of cross section size and emittance. The beam size results given by MATLAB are compared with the measured beam size in three of the four image points that the system has, obtaining a good agreement between them. This suggests that the first-order transfer matrix formalism is enough to simulate the optical behavior of the system. The present version of this interface enables the user to control, interact with and display a beam transport system. Parameters involved in the optics such as voltages applied to the lenses, terminal voltage and charge state of the selected ion can be modified using this interface, which gives great generality, as the optics behavior of the AMS system can be simulated for any ion species prior to operation.

J.M. Gmez-Guzmn; I. Gmez-Morilla; S.M. Enamorado-Bez; A.I. Moreno-Surez; A.R. Pinto-Gmez

2013-01-01T23:59:59.000Z

460

Toward CP-even Neutrino Beam  

E-Print Network [OSTI]

The best method of measuring CP violating effect in neutrino oscillation experiments is to construct and use a neutrino beam made of an ideal mixture of $\\bar{\

A. Fukumi; I. Nakano; H. Nanjo; N. Sasao; S. Sato; M. Yoshimura

2006-12-20T23:59:59.000Z

Note: This page contains sample records for the topic "molecular beam mass" 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.


461

PowerBeam Inc | Open Energy Information  

Open Energy Info (EERE)

California Zip: CA 94085 Product: PowerBeam holds the patent to a power transmission technology that produces wireless electricity. Coordinates: 32.780338, -96.547405 Show...

462

A traveling wave piezoelectric beam robot  

Science Journals Connector (OSTI)

In this paper, the operation principles of a traveling wave piezoelectric beam robot are presented. A prototype consisting of an aluminum beam structure, with two non-collocated piezoelectric patches bonded on its surface, was fabricated and tested to demonstrate the generation of a traveling wave on the beam based on the one mode excitation and the two mode excitation operation principles for propulsion. A numerical model was developed and used to study and optimize the generated motion of the piezoelectric beam robot. Experimental characterization of the robot for the two types of operation has been carried out, a comparison between them is made and results are given in this paper.

H Hariri; Y Bernard; A Razek

2014-01-01T23:59:59.000Z

463

Sandia National Laboratories: ion beam assisted deposition  

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

ion beam assisted deposition Sandia, Los Alamos, Superconducting Technologies Inc., & Superpower: Solution Deposition Planarization On March 20, 2013, in CINT, Facilities, Grid...

464

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

465

Probing Organic Transistors with Infrared Beams  

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

Probing Organic Transistors with Infrared Beams Print Silicon-based transistors are well-understood, basic components of contemporary electronic technology. In contrast, there is...

466

Ultrasonic imaging with limited-diffraction beams  

E-Print Network [OSTI]

Limited-diffraction beams are a class of waves that may be localized in space and time. Theoretically, these beams are propagation invariant and can propagate to an infinite distance without spreading. In practice, when these beams are produced with wave sources of a finite aperture and energy, they have a very large depth of field, meaning that they can keep a small beam width over a large distance. Because of this property, limited-diffraction beams may have applications in various areas such as medical imaging and tissue characterization. In this paper, fundamentals of limited-diffraction beams are reviewed and the studies of these beams are put into a unified theoretical framework. Theory of limited-diffraction beams is further developed. New limited-diffraction solutions to Klein-Gordon Equation and Schrodinger Equation, as well as limited-diffraction solutions to these equations in confined spaces are obtained. The relationship between the transformation that converts any solutions to an (-1)-dimensional wave equation to limited-diffraction solutions of an -dimensional equation and the Lorentz transformation is clarified and extended. The transformation is also applied to the Klein-Gordon Equation. In addition, applications of limited-diffraction beams are summarized.

Jian-yu Lu

2006-03-28T23:59:59.000Z

467

Science with Beams of Radioactive Isotopes  

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

2015 The International Chemical Congress of Pacific Basin Societies Science with Beams of Radioactive Isotopes ( 340) Honolulu, Hawaii, USA December 15-20, 2015 Science...

468

Low-noise macroscopic twin beams  

E-Print Network [OSTI]

Applying a multiphoton-subtraction technique to two-color macroscopic squeezed vacuum state of light generated via high-gain parametric down conversion we conditionally prepare a new state of light: bright multi-mode low-noise twin beams. The obtained results demonstrate up to 8-fold suppression of noise in each beam while preserving and even moderately improving the nonclassical photon number correlations between the beams. The prepared low-noise macroscopic state, containing up to 2000 photons per mode, is not among the states achievable through nonlinear optical processes. The proposed technique substantially improves the usefulness of twin beams for quantum technologies.

Timur Sh. Iskhakov; Vladyslav C. Usenko; Radim Filip; Maria V. Chekhova; Gerd Leuchs

2014-08-27T23:59:59.000Z

469

BEAM COUPLING PHENOMENA IN FAST KICKER SYSTEMS.  

SciTech Connect (OSTI)

Beam coupling phenomena have been observed in most fast kicker systems through out Brookhaven Collider-Accelerator complex. With ever-higher beam intensity, the signature of the beam becomes increasingly recognizable. The beam coupling at high intensity produced additional heat dissipation in high voltage modulator, thyratron grids, thyratron driver circuit sufficient to damage some components, and causes trigger instability. In this paper, we will present our observations, basic coupling mode analysis, relevance to the magnet structures, issues related to the existing high voltage modulators, and considerations of the future design of the fast kicker systems.

ZHANG,W.; AHRENS,L.A.; GLENN,J.; SANDBERG,J.; TSOUPAS,N.

2001-06-18T23:59:59.000Z

470

Beam Characterization at the Neutron Radiography Facility  

SciTech Connect (OSTI)

The quality of a neutron imaging beam directly impacts the quality of radiographic images produced using that beam. Fully characterizing a neutron beam, including determination of the beams effective length-to-diameter ratio, neutron flux profile, energy spectrum, image quality, and beam divergence, is vital for producing quality radiographic images. This project characterized the east neutron imaging beamline at the Idaho National Laboratory Neutron Radiography Reactor (NRAD). The experiments which measured the beams effective length-to-diameter ratio and image quality are based on American Society for Testing and Materials (ASTM) standards. An analysis of the image produced by a calibrated phantom measured the beam divergence. The energy spectrum measurements consist of a series of foil irradiations using a selection of activation foils, compared to the results produced by a Monte Carlo n-Particle (MCNP) model of the beamline. Improvement of the existing NRAD MCNP beamline model includes validation of the models energy spectrum and the development of enhanced image simulation methods. The image simulation methods predict the radiographic image of an object based on the foil reaction rate data obtained by placing a model of the object in front of the image plane in an MCNP beamline model.

Sarah Morgan; Jeffrey King

2013-01-01T23:59:59.000Z

471

Study of beam optics and beam halo by integrated modeling of negative ion beams from plasma meniscus formation to beam acceleration  

SciTech Connect (OSTI)

To understand the physical mechanism of the beam halo formation in negative ion beams, a two-dimensional particle-in-cell code for simulating the trajectories of negative ions created via surface production has been developed. The simulation code reproduces a beam halo observed in an actual negative ion beam. The negative ions extracted from the periphery of the plasma meniscus (an electro-static lens in a source plasma) are over-focused in the extractor due to large curvature of the meniscus.

Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan)] [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Okuda, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)] [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Hanada, M.; Kojima, A. [Japan Atomic Energy Agency, 801-1 Mukouyama, Naka 319-0913 (Japan)] [Japan Atomic Energy Agency, 801-1 Mukouyama, Naka 319-0913 (Japan)

2013-01-14T23:59:59.000Z

472

Summary of the LARP Mini-Workshop on Beam-Beam Compensation 2007  

SciTech Connect (OSTI)

The LARP Mini-Workshop on Beam-Beam Compensation 2007 was held at SLAC, 2-4 July 2007. It was attended by 33 participants from 10 institutions in Asia, Europe, and America. 26 presentations were given, while more than one third of the time was allocated to discussions. The workshop web site is Ref. [1]. The workshop's main focus was on long-range and head-on beam-beam compensation, with a view towards application in the LHC. Other topics included the beam-beam performance of previous, existing and future circular colliders; beam-beam simulations; new operating modes, theory, and unexplained phenomena. This summary is also published as Ref. [2].

Fischer, Wolfram; /Brookhaven; Bruning, Oliver S.; Koutchouk, J.P.; Zimmermann, F.; /CERN; Sen, T.; Shiltsev, V.; /Fermilab; Ohmi, K.; /KEK, Tsukuba; Furman, M.; /LBL, Berkeley; Cai, Y.; Chao, A.; /SLAC

2011-11-07T23:59:59.000Z

473

Method and apparatus for laser-controlled proton beam radiology  

DOE Patents [OSTI]

A proton beam radiology system provides cancer treatment and proton radiography. The system includes an accelerator for producing an H.sup.- beam and a laser source for generating a laser beam. A photodetachment module is located proximate the periphery of the accelerator. The photodetachment module combines the H.sup.- beam and laser beam to produce a neutral beam therefrom within a subsection of the H.sup.- beam. The photodetachment module emits the neutral beam along a trajectory defined by the laser beam. The photodetachment module includes a stripping foil which forms a proton beam from the neutral beam. The proton beam is delivered to a conveyance segment which transports the proton beam to a patient treatment station. The photodetachment module further includes a laser scanner which moves the laser beam along a path transverse to the cross-section of the H.sup.- beam in order to form the neutral beam in subsections of the H.sup.- beam. As the scanning laser moves across the H.sup.- beam, it similarly varies the trajectory of the proton beam emitted from the photodetachment module and in turn varies the target location of the proton beam upon the patient. Intensity modulation of the proton beam can also be achieved by controlling the output of the laser.

Johnstone, Carol J. (Warrenville, IL)

1998-01-01T23:59:59.000Z

474

Method and apparatus for laser-controlled proton beam radiology  

DOE Patents [OSTI]

A proton beam radiology system provides cancer treatment and proton radiography. The system includes an accelerator for producing an H{sup {minus}} beam and a laser source for generating a laser beam. A photodetachment module is located proximate the periphery of the accelerator. The photodetachment module combines the H{sup {minus}} beam and laser beam to produce a neutral beam therefrom within a subsection of the H{sup {minus}} beam. The photodetachment module emits the neutral beam along a trajectory defined by the laser beam. The photodetachment module includes a stripping foil which forms a proton beam from the neutral beam. The proton beam is delivered to a conveyance segment which transports the proton beam to a patient treatment station. The photodetachment module further includes a laser scanner which moves the laser beam along a path transverse to the cross-section of the H{sup {minus}} beam in order to form the neutral beam in subsections of the H{sup {minus}} beam. As the scanning laser moves across the H{sup {minus}} beam, it similarly varies the trajectory of the proton beam emitted from the photodetachment module and in turn varies the target location of the proton beam upon the patient. Intensity modulation of the proton beam can also be achieved by controlling the output of the laser. 9 figs.

Johnstone, C.J.

1998-06-02T23:59:59.000Z

475

Simulations of coherent beam-beam effects with head-on compensation  

SciTech Connect (OSTI)

Electron lenses are under construction for installation in RHIC in order to mitigate the head-on beam-beam effects. This would allow operation with higher bunch intensity and result in a significant increase in luminosity. We report on recent strong-strong simulations and experiments that were carried out using the RHIC upgrade parameters to assess the impact of coherent beam-beam effects in the presence of head-on compensation.

White S.; Fischer, W.; Luo. Y.

2012-05-20T23:59:59.000Z

476

The molecular universe  

Science Journals Connector (OSTI)

......astrochemistry. Molecules play a fundamental role in many regions...astronomical chemical engine would simply grind to...the difference between diesel and petrol engines...need a vast supply of fundamental data on atomic, molecular...come. Molecules play a fundamental role in many regions......

Helen J Fraser; Martin R S McCoustra; David A Williams

2002-04-01T23:59:59.000Z

477

POLYMERSYNTHESIS& MOLECULAR/SOLUTION  

E-Print Network [OSTI]

/POSTDOC 404 GRAD/POSTDOC 405 GRAD 406 DARKENEDROOM 419A MOLECULAR BIOLOGY 419 HOTLAB 422BA MICROBIOLOGY 422B memory Sachin Mali and Eric Ouellette, Ph.D. students (Gilbert Lab): Demo of Instron and research explanation Shiril Sivan, Ph.D. student (Gilbert Lab): Demonstration of Hirox microscope, and imaging

Mather, Patrick T.

478

Cascaded injection resonator for coherent beam combining of laser arrays  

DOE Patents [OSTI]

The invention provides a cascaded injection resonator for coherent beam combining of laser arrays. The resonator comprises a plurality of laser emitters arranged along at least one plane and a beam sampler for reflecting at least a portion of each laser beam that impinges on the beam sampler, the portion of each laser beam from one of the laser emitters being reflected back to another one of the laser emitters to cause a beam to be generated from the other one of the laser emitters to the beam reflector. The beam sampler also transmits a portion of each laser beam to produce a laser output beam such that a plurality of laser output beams of the same frequency are produced. An injection laser beam is directed to a first laser emitter to begin a process of generating and reflecting a laser beam from one laser emitter to another laser emitter in the plurality. A method of practicing the invention is also disclosed.

Kireev, Vassili [Sunnyvale, CA; Liu, Yun; Protopopescu, Vladimir [Knoxville, TN; Braiman, Yehuda [Oak Ridge, TN

2008-10-21T23:59:59.000Z

479

Rugged miniaturized mass sensors for use in plutonium conversion processes  

SciTech Connect (OSTI)

Ionization is produced either through Plasma Desorption, in the case of a solid, using fission fragments from a Cf-252 source; or in the case of a gas, via an electron avalanche from the impact on a microsphere detector of {alpha} particles from a radioactive source. The gaseous compound analysis yielded multiple peaks on parent ion and molecular fragments. In the solid compound analysis, the results indicated that solid-state mass spectrometry will provide important information about the degradation of materials by measured changes in molecular weight.

Schweikert, E.A.; James, W.D. [Texas A and M Univ., College Station, TX (United States). Cen