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1

Multiphoton ionization and ion-pair formation in molecular hydrogen  

SciTech Connect

We have investigated both photoionization and ion-pair formation in molecular hydrogen by using double-resonance excitation via the E,F {sup 1}{Sigma}{sub g}{sup +}, v=6 level. The energetic threshold for ion-pair formation occurs just below the H{sub 2}{sup +} X {sup 2}{Sigma}{sub g}{sup +}, v{sup +}=9 ionization. threshold. The spectrum in this region was studied by using both conventional and constant-ionic-state photoelectron spectroscopy, as well as by monitoring the H{sup {minus}} production. The decay dynamics in this region are extremely rich, because excited levels may decay by rotational and vibrational autoionization, by predissociation to neutral H + H* (n=2,3,4), by predissociation to the ion pair H{sup +} + H{sup {minus}}, and by fluorescence. In addition, the dissociative potential curve of the 2p{sigma}{sub u}3s{sigma}{sub g} {sup 1}{Sigma}{sub u}{sup +} doubly excited electronic state crosses the H{sub 2}{sup +} X {sup 2}{Sigma}{sub u}{sup +} potential curve in the same energy region, and the electronic autoionization of this state is found to significantly influence these decay processes.

Pratt, S.T.; McCormack, E.F.; Dehmer, J.L.; Dehmer, P.M.

1992-09-01T23:59:59.000Z

2

Coherent Electromagnetic Heavy Ion Reactions: (1) Exact Treatment of Pair Production and Ionization; (2) Mutual Coulomb Dissociation  

SciTech Connect

Some recent theoretical results on coherent electromagnetic processes in ultrarelativistic heavy ion reactions are surveyed. In ultrarelativistic heavy ion collisions, Coulomb induced cross sections are huge, much larger than geometric. For the RHIC case of 100 GeV x 100 GeV colliding gold ions the predicted cross section for bound-electron positron pairs is about 110 barns. The corresponding cross section for continuum electron-positron pairs has recently been recalculated to be 34,000 barns, consistent with the result of the classic formula of Landau and Lifshitz. The cross section for Coulomb dissociation of the nucleus is about 95 barns, and the cross section for ionization of a single electron on one of the ions is about 100,000 barns.

Baltz, A. J.

1999-05-10T23:59:59.000Z

3

Changing Ionization Conditions in SDSS Galaxies with AGN as a Function of Environment from Pairs to Clusters  

E-Print Network (OSTI)

We study how AGN activity changes across environments from galaxy pairs to clusters using $143\\, 843$ galaxies with $zenvironmental effects while removing contamination. We confirm that galaxy interactions enhance AGN activity. However, conditions in the central regions of clusters are inhospitable for AGN activity even if galaxies are in pairs. These results can be explained through models of gas dynamics in which pair interactions stimulate the transfer of gas to the nucleus and clusters suppress gas availability for accretion onto the central black hole.

Khabiboulline, Emil T; Silverman, John D; Ellison, Sara L; Mendel, J Trevor; Patton, David R

2014-01-01T23:59:59.000Z

4

Ionization chamber  

DOE Patents (OSTI)

An ionization chamber has separate drift and detection regions electrically isolated from each other by a fine wire grid. A relatively weak electric field can be maintained in the drift region when the grid and another electrode in the chamber are connected to a high voltage source. A much stronger electric field can be provided in the detection region by connecting wire electrodes therein to another high voltage source. The detection region can thus be operated in a proportional mode when a suitable gas is contained in the chamber. High resolution output pulse waveforms are provided across a resistor connected to the detection region anode, after ionizing radiation enters the drift region and ionize the gas.

Walenta, Albert H. (Port Jefferson Station, NY)

1981-01-01T23:59:59.000Z

5

Dissociative-ionization cross sections for 12-keV-electron impact on CO{sub 2}  

SciTech Connect

The dissociative ionization of a CO{sub 2} molecule is studied at an electron energy of 12 keV using the multiple ion coincidence imaging technique. The absolute partial ionization cross sections and the precursor-specific absolute partial ionization cross sections of resulting fragment ions are obtained and reported. It is found that {approx}75% of single ionization, 22% of double ionization, and {approx}2% of triple ionization of the parent molecule contribute to the total fragment ion yield; quadruple ionization of CO{sub 2} is found to make a negligibly small contribution. Furthermore, the absolute partial ionization cross sections for ion-pair and ion-triple formation are measured for nine dissociative ionization channels of up to a quadruply ionized CO{sub 2} molecule. In addition, the branching ratios for single-ion, ion-pair, and ion-triple formation are also determined.

Bhatt, Pragya; Singh, Raj; Yadav, Namita; Shanker, R. [Atomic Physics Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005 (India)

2011-10-15T23:59:59.000Z

6

Photoinduced electron transfer in contact ion pairs  

SciTech Connect

Contact ion pair (CIP) formation is especially relevant to the reactivity of organic and organometallic nucleophiles and electrophiles in solution. The authors felt that the intermolecular charge-transfer (CT) absorptions which commonly accompany the interaction of uncharged nucleophiles (donors) with electrophiles (acceptors) could also provide the experimental means to assess CIP behavior. Accordingly they examined the CT excitations from CIPs of carbonylmetallate anions in this study, since they are known to be effective nucleophiles with relatively low ionization potentials.

Bockman, T.M.; Kochi, J.K.

1988-02-17T23:59:59.000Z

7

Risks from ionizing radiation  

Science Journals Connector (OSTI)

... RADON indoors now accounts for nearly half of the average UK population exposure to ionizing radiation ... exposure to ionizing radiation. We believe that the extent of the variation in exposure to radon in the United Kingdom and else-where and its magnitude in relation to exposures from ...

R. H. Clarke; T. R. E. Southwood

1989-03-16T23:59:59.000Z

8

Ionization monitor with improved ultra-high megohm resistor  

DOE Patents (OSTI)

An ionization monitor measures extremely small currents using a resistor containing a beta emitter to generate ion-pairs which are collected as current when the device is used as a feedback resistor in an electrometer circuit. By varying the amount of beta emitter, the resistance of the resistor may be varied.

Burgess, Edward T. (Carlisle, OH)

1988-11-05T23:59:59.000Z

9

Plasma-assisted catalytic ionization using porous nickel plate  

SciTech Connect

Hydrogen atomic pair ions, i.e., H{sup +} and H{sup -} ions, are produced by plasma-assisted catalytic ionization using a porous nickel plate. Positive ions in a hydrogen plasma generated by dc arc discharge are irradiated to the porous plate, and pair ions are produced from the back of the irradiation plane. It becomes clear that the production quantity of pair ions mainly depends on the irradiation current of positive ions and the irradiation energy affects the production efficiency of H{sup -} ions.

Oohara, W.; Maeda, T.; Higuchi, T. [Department of Electronic Device Engineering, Yamaguchi University, Ube 755-8611 (Japan)

2011-09-15T23:59:59.000Z

10

Soft ionization of thermally evaporated hypergolic ionic liquid aerosols  

SciTech Connect

Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim+][Tf2N?]), and a reactive hypergolic ionic liquid, 1- Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim+][Dca?]), are generated by vaporizing ionic liquid submicron aerosol particles for the first time; the vaporized species are investigated by dissociative ionization with tunable vacuum ultraviolet (VUV) light, exhibiting clear intact cations, Emim+ and Bmim+, presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Photoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim+][Tf2N?] ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (~;;0.3 eV), attributed to reduced internal energy of the isolated ion pairs. The method of ionic liquid submicron aerosol particle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally ?cooler? source of isolated intact ion pairs in the gas phase compared to effusive sources.

University of California; ERC, Incorporated, Edwards Air Force Base; Air Force Research Laboratory, Edwards Air Force Base; National Synchrotron Radiation Research Center (NSRRC); Koh, Christine J.; Liu, Chen-Lin; Harmon, Christopher W.; Strasser, Daniel; Golan, Amir; Kostko, Oleg; Chambreau, Steven D.; L.Vaghjiani, Ghanshyam; Leone, Stephen R.

2012-03-16T23:59:59.000Z

11

Pairing in dense lithium  

Science Journals Connector (OSTI)

... of valence electrons. Here we report the results of first-principles calculations, indicating that lithium, the band structure of which is largely free-electron-like at ordinary densities, does ... b.c.c.) becomes unstable to a pairing of the ions. Once paired, lithium possesses an even number of electrons per primitive cell which, although not sufficient, is ...

J. B. Neaton; N. W. Ashcroft

1999-07-08T23:59:59.000Z

12

(Resonance ionization spectroscopy)  

SciTech Connect

J. P. Young attended the Fifth International Symposium on Resonance Ionization Spectroscopy and presented an invited oral presentation on research he and coworkers had carried out in applying diode lasers to resonance ionization mass spectrometry. A summary of the conference is given along with an assessment of some of the presentations that the author found of interest. Young also visited Professor Marassi at the University of Camerino to present a seminar and discuss mutual interests in a new molten salt research project of the author. Some of the studies at Camerino are described. Ideas concerning the author's research that came from private discussions are also presented here.

Young, J.P.

1990-10-11T23:59:59.000Z

13

Cooper Pairs in Insulators?!  

ScienceCinema (OSTI)

Nearly 50 years elapsed between the discovery of superconductivity and the emergence of the microscopic theory describing this zero resistance state. The explanation required a novel phase of matter in which conduction electrons joined in weakly bound pairs and condensed with other pairs into a single quantum state. Surprisingly, this Cooper pair formation has also been invoked to account for recently uncovered high-resistance or insulating phases of matter. To address this possibility, we have used nanotechnology to create an insulating system that we can probe directly for Cooper pairs. I will present the evidence that Cooper pairs exist and dominate the electrical transport in these insulators and I will discuss how these findings provide new insight into superconductor to insulator quantum phase transitions. 

James Valles

2010-01-08T23:59:59.000Z

14

Coulomb pair creation II  

Science Journals Connector (OSTI)

In a previous paper [1] we investigated the general theoretical background of electron-positron pair creation in strong external electric fields. In this paper we apply the general formalism to calculate the p...

P. Hraskó; L. Földy; A. Tóth

1988-03-01T23:59:59.000Z

15

Hysteresis of ionization waves  

SciTech Connect

A quasi-logistic, nonlinear model for ionization wave modes is introduced. Modes are due to finite size of the discharge and current feedback. The model consists of competing coupled modes and it incorporates spatial wave amplitude saturation. The hysteresis of wave mode transitions under current variation is reproduced. Sidebands are predicted by the model and found in experimental data. The ad hoc model is equivalent to a general--so-called universal--approach from bifurcation theory.

Dinklage, A. [Max-Planck-Institut fuer Plasmaphysik, EURATOM-Association, Wendelsteinstr. 1, 17491 Greifswald (Germany); Bruhn, B.; Testrich, H. [Institut fuer Physik, E.-M.-Arndt Universitaet Greifswald, Felix-Hausdorff-Str. 6, 17487 Greifswald (Germany); Wilke, C. [Leibniz-Institut fuer Plasmaforschung und Technologie, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany)

2008-06-15T23:59:59.000Z

16

Electrospray Ionization Mass Spectrometry  

SciTech Connect

Electrospray Ionization (ESI) is a process whereby gas phase ions are created from molecules in solution. As a solution exits a narrow tube in the presence of a strong electric field, an aerosol of charged droplets are is formed that produces gas phase ions as they it desolvates. ESI-MS comprises the creation of ions by ESI and the determination of their mass to charge ratio (m/z) by MS.

Kelly, Ryan T.; Marginean, Ioan; Tang, Keqi

2014-06-13T23:59:59.000Z

17

Modulated voltage metastable ionization detector  

SciTech Connect

Metastable ionization detectors used for chromatographic analysis usually employa fixed high voltage for the ionization potential. For this reason, the operating range is limited to about three orders of magnitude. By use of the technique disclosed in the instant invention, operating ranges of about nine orders of magnitude are obtained. The output current from a metastable ionization detector (MID) is applied to a modulation voltage circuit. An adjustment is made to balance out the background current, and an output current, above background, is applied to an input of a strip chart recorder. For low level concentrations, i.e., low detected output current, the ionization potential will be at a maximum and the metastable ionization detector will operate at its most sensitive level. When the detected current from the metastable ionization detector increases above a predetermined threshold level, a voltage control circuit is activated which turns on a high voltage transistor which acts to reduce the ionization potential. The ionization potential applied to the metastable ionization detector is then varied so as to maintain the detected signal level constant. The variation in ionization potential is now related to the concentration fo the constituent and a representative amplitude is applied to another input of said strip chart recorder.

Carle, G. C.; Humphry, D. E.; Kojiro, D. R.

1985-08-27T23:59:59.000Z

18

A surface ionization source  

E-Print Network (OSTI)

The Einzel Lens. 2 The Quadrupole Triplet . . 3. The Beam Scanner. . . 4 The Four-plate Detectors and Faraday Cups. III TESTING AND OPTIMIZING THE BEAM LINE 10 12 13 A. Initial Results. IV THE THEORY OF SURFACE IONIZATION . . . . . V ION SOURCES. 21... aperture and through a beam scanner. The scanner translates the beam's cross-section to an image visible on the oscilloscope A movable Faraday cup connected to a sensitive electrometer is used to maximize the beam transmission at the opening into the 2...

Buzatu, Daniel J.

2012-06-07T23:59:59.000Z

19

Plasma Production via Field Ionization  

SciTech Connect

Plasma production via field ionization occurs when an incoming particle beam is sufficiently dense that the electric field associated with the beam ionizes a neutral vapor or gas. Experiments conducted at the Stanford Linear Accelerator Center explore the threshold conditions necessary to induce field ionization by an electron beam in a neutral lithium vapor. By independently varying the transverse beam size, number of electrons per bunch or bunch length, the radial component of the electric field is controlled to be above or below the threshold for field ionization. Additional experiments ionized neutral xenon and neutral nitric oxide by varying the incoming beam's bunch length. A self-ionized plasma is an essential step for the viability of plasma-based accelerators for future high-energy experiments.

O'Connell, C.L.; Barnes, C.D.; Decker, F.; Hogan, M.J.; Iverson, R.; Krejcik, P.; Siemann, R.; Walz, D.R.; /SLAC; Clayton, C.E.; Huang, C.; Johnson, D.K.; Joshi, C.; Lu,; Marsh, K.A.; Mori, W.; Zhou, M.; /UCLA; Deng, S.; Katsouleas, T.; Muggli, P.; Oz, E.; /Southern California U.

2007-01-02T23:59:59.000Z

20

Ionizing radiation detector  

DOE Patents (OSTI)

An ionizing radiation detector is provided which is based on the principle of analog electronic integration of radiation sensor currents in the sub-pico to nano ampere range between fixed voltage switching thresholds with automatic voltage reversal each time the appropriate threshold is reached. The thresholds are provided by a first NAND gate Schmitt trigger which is coupled with a second NAND gate Schmitt trigger operating in an alternate switching state from the first gate to turn either a visible or audible indicating device on and off in response to the gate switching rate which is indicative of the level of radiation being sensed. The detector can be configured as a small, personal radiation dosimeter which is simple to operate and responsive over a dynamic range of at least 0.01 to 1000 R/hr.

Thacker, Louis H. (Knoxville, TN)

1990-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

Pair annotation: adaption of pair programming to corpus annotation  

Science Journals Connector (OSTI)

This paper will introduce a procedure that we call pair annotation after pair programming. We describe initial annotation procedure of the TDB, followed by the inception of the pair annotation idea and how it came to be used in the Turkish Discourse ...

I??n Demir?ahin; Ihsan Yalç?nkaya; Deniz Zeyrek

2012-07-01T23:59:59.000Z

22

Proteasome Structures Affected by Ionizing Radiation  

Science Journals Connector (OSTI)

...Effect of ionizing radiation on 26S but...radiation doses, and immediately...the dose range 1 to 20 Gy...ionizing radiation induced a...38), ionizing radiation (39...over a wide range of radiation doses and further...

Milena Pervan; Keisuke S. Iwamoto; and William H. McBride

2005-07-01T23:59:59.000Z

23

Multiprocessor switch with selective pairing  

DOE Patents (OSTI)

System, method and computer program product for a multiprocessing system to offer selective pairing of processor cores for increased processing reliability. A selective pairing facility is provided that selectively connects, i.e., pairs, multiple microprocessor or processor cores to provide one highly reliable thread (or thread group). Each paired microprocessor or processor cores that provide one highly reliable thread for high-reliability connect with a system components such as a memory "nest" (or memory hierarchy), an optional system controller, and optional interrupt controller, optional I/O or peripheral devices, etc. The memory nest is attached to a selective pairing facility via a switch or a bus

Gara, Alan; Gschwind, Michael K; Salapura, Valentina

2014-03-11T23:59:59.000Z

24

Optical ionization detector  

DOE Patents (OSTI)

An optical ionization detector wherein a beam of light is split so that one arm passes through a fiber optics and the other arm passes through a gas-filled region, and uses interferometry to detect density changes in a gas when charged particles pass through it. The gas-filled region of the detector is subjected to a high electric field and as a charged particle traverses this gas region electrons are freed from the cathode and accelerated so as to generate an electron avalanche which is collected on the anode. The gas density is effected by the electron avalanche formation and if the index or refraction is proportional to the gas density the index will change accordingly. The detector uses this index change by modulating the one arm of the split light beam passing through the gas, with respect to the other arm that is passed through the fiber optic. Upon recombining of the beams, interference fringe changes as a function of the index change indicates the passage of charged particles through the gaseous medium. 3 figures.

Wuest, C.R.; Lowry, M.E.

1994-03-29T23:59:59.000Z

25

Optical ionization detector  

DOE Patents (OSTI)

An optical ionization detector wherein a beam of light is split so that one arm passes through a fiber optics and the other arm passes through a gas-filled region, and uses interferometry to detect density changes in a gas when charged particles pass through it. The gas-filled region of the detector is subjected to a high electric field and as a charged particle traverses this gas region electrons are freed from the cathode and accelerated so as to generate an electron avalanche which is collected on the anode. The gas density is effected by the electron avalanche formation and if the index or refraction is proportional to the gas density the index will change accordingly. The detector uses this index change by modulating the one arm of the split light beam passing through the gas, with respect to the other arm that is passed through the fiber optic. Upon recombining of the beams, interference fringe changes as a function of the index change indicates the passage of charged particles through the gaseous medium.

Wuest, Craig R. (Danville, CA); Lowry, Mark E. (Castro Valley, CA)

1994-01-01T23:59:59.000Z

26

Resonance Ionization Laser Ion Sources  

E-Print Network (OSTI)

The application of the technique of laser resonance ionization to the production of singly charged ions at radioactive ion beam facilities is discussed. The ability to combine high efficiency and element selectivity makes a resonance ionization laser ion source (RILIS) an important component of many radioactive ion beam facilities. At CERN, for example, the RILIS is the most commonly used ion source of the ISOLDE facility, with a yearly operating time of up to 3000 hours. For some isotopes the RILIS can also be used as a fast and sensitive laser spectroscopy tool, provided that the spectral resolution is sufficiently high to reveal the influence of nuclear structure on the atomic spectra. This enables the study of nuclear properties of isotopes with production rates even lower than one ion per second and, in some cases, enables isomer selective ionization. The solutions available for the implementation of resonance laser ionization at radioactive ion beam facilities are summarized. Aspects such as the laser r...

Marsh, B

2013-01-01T23:59:59.000Z

27

Field ionization from carbon nanofibers  

E-Print Network (OSTI)

The Micro Gas Analyzer project aims to develop power-efficient, high resolution, high sensitivity, portable and real-time gas sensors. We developed a field ionizer array based on gated CNTs. Arrays of CNTs are used because ...

Adeoti, Bosun J

2008-01-01T23:59:59.000Z

28

Ionizing Radiation Injury (South Carolina)  

Energy.gov (U.S. Department of Energy (DOE))

This legislation applies to employers that have more than one employee who engages in activities which involve the presence of ionizing radiation. Employers with less than three employees can...

29

Anomalous laser-induced ionization rates of molecules and rare-gas atoms  

SciTech Connect

Electron tunnel ionization is considered as the mechanism for producing free electrons in gases under laser radiation. The Keldysh result and the Ammosov-Delone-Krainov (ADK) formulation are amended by considering the excess forces due to the interaction of the electric field of the laser with the electron cloud in a simple mass-on-a-spring approximation. The result of this excess force is a kinetic energy that is directed along the polarization vector of the laser field and an induced potential energy that are proposed as a determining factor in electron tunnel ionization. Relative ionization rates for various pairs of gases are calculated and compared with reported figures. Comparisons were made between several combinations of O{sub 2}, Xe, Ar, N{sub 2}, Cl{sub 2}, H{sub 2}, CO, Kr, NO, F{sub 2}, and D{sub 2}. Predicted ratios of ionization rates between pairs of gases are compared to ADK predictions. Apparently anomalous ionization rates of O{sub 2}, D{sub 2}, and H{sub 2} are explained. A simple expression is developed that reveals why the ionization rate of Xe is about an order of magnitude larger than that of O{sub 2} even though their ionization potentials are nearly identical; why CO is only about half that of Kr even though their ionization potentials are nearly the same; why the ratio of O{sub 2} to O is about ten times larger than predicted by ADK; and why the ratio of NO to Xe is about an order of magnitude less than predicted by ADK.

Bettis, Jerry Ray [5701 Woodlake Drive, Stillwater, Oklahoma 74074 (United States)

2009-12-15T23:59:59.000Z

30

Self-consistent chemical model of partially ionized plasmas  

Science Journals Connector (OSTI)

A simple renormalization theory of plasma particle interactions is proposed. It primarily stems from generic properties of equilibrium distribution functions and allows one to obtain the so-called generalized Poisson-Boltzmann equation for an effective interaction potential of two chosen particles in the presence of a third one. The same equation is then strictly derived from the Bogolyubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy for equilibrium distribution functions in the pair correlation approximation. This enables one to construct a self-consistent chemical model of partially ionized plasmas, correctly accounting for the close interrelation of charged and neutral components thereof. Minimization of the system free energy provides ionization equilibrium and, thus, permits one to study the plasma composition in a wide range of its parameters. Unlike standard chemical models, the proposed one allows one to study the system correlation functions and thereby to obtain an equation of state which agrees well with exact results of quantum-mechanical activity expansions. It is shown that the plasma and neutral components are strongly interrelated, which results in the short-range order formation in the corresponding subsystem. The mathematical form of the results obtained enables one to both firmly establish this fact and to determine a characteristic length of the structure formation. Since the cornerstone of the proposed self-consistent chemical model of partially ionized plasmas is an effective pairwise interaction potential, it immediately provides quite an efficient calculation scheme not only for thermodynamical functions but for transport coefficients as well.

Yu. V. Arkhipov, F. B. Baimbetov, and A. E. Davletov

2011-01-21T23:59:59.000Z

31

Electron impact ionization of neutral and ionized fullerenes: ionization cross–sections and kinetic energy release  

Science Journals Connector (OSTI)

...and 1000 eV, with an energy spread of approximately...exit electrode by an electric field penetrating from...measurements of appearance energies and ionization cross-sections...measurements have been car- ried out (in both...cross-sections versus electron energy from threshold up to...

1999-01-01T23:59:59.000Z

32

Lesson 4 - Ionizing Radiation | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

4 - Ionizing Radiation 4 - Ionizing Radiation Lesson 4 - Ionizing Radiation Lesson Three showed that unstable isotopes emit energy as they become more stable. This energy is known as radiation. This lesson explores forms of radiation, where radiation is found, how we detect and measure radiation, what sources of radiation people are exposed to, whether radiation is harmful, and how we can limit our exposure. Specific topics covered in this lesson include: Types of radiation Non-ionizing Ionizing Forms of ionizing radiation Alpha particles Beta particles Gamma rays Radiation Decay chain Half-life Dose Radiation measurements Sources of radiation Average annual exposure Lesson 4 - Ionizing Radiation.pptx More Documents & Publications DOE-HDBK-1130-2008 DOE-HDBK-1130-2008 DOE-HDBK-1130-2007

33

Accelerated Cellulose Depolymerization Catalyzed by Paired Metal...  

NLE Websites -- All DOE Office Websites (Extended Search)

Depolymerization Catalyzed by Paired Metal Chlorides in Ionic Liquid Solvent. Accelerated Cellulose Depolymerization Catalyzed by Paired Metal Chlorides in Ionic Liquid...

34

Pair Multiplicities and Pulsar Death  

E-Print Network (OSTI)

Through a simple model of particle acceleration and pair creation above the polar caps of rotation-powered pulsars, we calculate the height of the pair-formation front (PFF) and the dominant photon emission mechanism for the pulsars in the Princeton catalog. We find that for most low- and moderate-field pulsars, the height of the pair formation front and the final Lorentz factor of the primary beam is set by nonresonant inverse Compton scattering (NRICS), in the Klein-Nishina limit. NRICS is capable of creating pairs over a wide range of pulsar parameters without invoking a magnetic field more complicated than a centered dipole, although we still require a reduced radius of curvature for most millisecond pulsars. For short-period pulsars, the dominant process is curvature radiation, while for extremely high-field pulsars, it is resonant inverse Compton scattering (RICS). The dividing point between NRICS dominance and curvature dominance is very temperature-dependent; large numbers of pulsars dominated by NRICS at a stellar temperature of $10^6$ K are dominated by curvature at $10^5$ K. We apply these results to pulsar death-line calculations and to the issue of particle injection into the Crab Nebula.

J. A. Hibschman; J. Arons

2001-02-09T23:59:59.000Z

35

Sample Desorption/Ionization From Mesoporous Silica  

NLE Websites -- All DOE Office Websites (Extended Search)

Sample Desorption/Ionization From Mesoporous Silica Sample Desorption/Ionization From Mesoporous Silica Sample Desorption/Ionization From Mesoporous Silica Mesoporous silica is shown to be a sample holder for laser desorption/ionization of mass spectrometry. Available for thumbnail of Feynman Center (505) 665-9090 Email Sample Desorption/Ionization From Mesoporous Silica Mesoporous silica is shown to be a sample holder for laser desorption/ionization of mass spectrometry. Supported mesoporous silica was prepared by coating an ethanolic silicate solution having a removable surfactant onto a substrate to produce a self-assembled, ordered, nanocomposite silica thin film. The surfactant was chosen to provide a desired pore size between about 1 nanometer diameter and 50 nanometers diameter. Removal of the surfactant resulted in a mesoporous silica thin

36

Ionization probes of molecular structure and chemistry  

SciTech Connect

Various photoionization processes provide very sensitive probes for the detection and understanding of the spectra of molecules relevant to combustion processes. The detection of ionization can be selective by using resonant multiphoton ionization or by exploiting the fact that different molecules have different sets of ionization potentials. Therefore, the structure and dynamics of individual molecules can be studied even in a mixed sample. The authors are continuing to develop methods for the selective spectroscopic detection of molecules by ionization, and to use these methods for the study of some molecules of combustion interest.

Johnson, P.M. [State Univ. of New York, Stony Brook (United States)

1993-12-01T23:59:59.000Z

37

Pair production in inhomogeneous fields  

SciTech Connect

We employ the recently developed worldline numerics, which combines string-inspired field theory methods with Monte Carlo techniques, to develop an algorithm for the computation of pair-production rates in scalar QED for inhomogeneous background fields. We test the algorithm with the classic Sauter potential, for which we compute the local production rate for the first time. Furthermore, we study the production rate for a superposition of a constant E field and a spatially oscillating field for various oscillation frequencies. Our results reveal that the approximation by a local derivative expansion already fails for frequencies small compared to the electron-mass scale, whereas for strongly oscillating fields a derivative expansion for the averaged field represents an acceptable approximation. The worldline picture makes the nonlocal nature of pair production transparent and facilitates a profound understanding of this important quantum phenomenon.

Gies, Holger; Klingmueller, Klaus [Institut fuer theoretische Physik, Universitaet Heidelberg, Philosophenweg 16, D-69120 Heidelberg (Germany)

2005-09-15T23:59:59.000Z

38

Pair production in inhomogeneous fields  

E-Print Network (OSTI)

We employ the recently developed worldline numerics, which combines string-inspired field theory methods with Monte-Carlo techniques, to develop an algorithm for the computation of pair-production rates in scalar QED for inhomogeneous background fields. We test the algorithm with the classic Sauter potential, for which we compute the local production rate for the first time. Furthermore, we study the production rate for a superposition of a constant E field and a spatially oscillating field for various oscillation frequencies. Our results reveal that the approximation by a local derivative expansion fails already for frequencies small compared to the electron mass scale, whereas for strongly oscillating fields a derivative expansion for the averaged field represents an acceptable approximation. The worldline picture makes the nonlocal nature of pair production transparent and facilitates a profound understanding of this important quantum phenomenon.

Holger Gies; Klaus Klingmuller

2005-05-12T23:59:59.000Z

39

Device for detecting ionizing radiation  

SciTech Connect

The present invention relates to ionizing radiation sensors, and , more particularly, to semiconductor spectrometers with thermoelectric cooling, and can most advantageously be used in mineral raw material exploration and evaluation under field conditions. The spectrometer comprises a vacuum chamber with an entrance window for passing the radiation therethrough. The vacuum chamber accommodates a thermoelectric cooler formed by a set of peltier elements. A heat conducting plate is mounted on the cold side of the thermoelectric cooler, and its hot side is provided with a radiator. Mounted on the heat conducting plate are sets of peltier elements, integral with the thermoelectric cooler and independent of one another. The peltier elements of these sets are stacked so as to develop the minimum temperature conditions on one set carrying a semiconductor detector and to provide the maximum refrigeration capacity conditions on the other set provided with the field-effect transistor mounted thereon.

Anatychuk, L.I.; Kharitonov, J.P.; Kusniruk, V.F.; Meir, V.A.; Melnik, A.P.; Ponomarev, V.S.; Skakodub, V.A.; Sokolov, A.D.; Subbotin, V.G.; Zhukovsky, A.N.

1980-10-28T23:59:59.000Z

40

Ionization tube simmer current circuit  

DOE Patents (OSTI)

A highly efficient flash lamp simmer current circuit utilizes a fifty percent duty cycle square wave pulse generator to pass a current over a current limiting inductor to a full wave rectifier. The DC output of the rectifier is then passed over a voltage smoothing capacitor through a reverse current blocking diode to a flash lamp tube to sustain ionization in the tube between discharges via a small simmer current. An alternate embodiment of the circuit combines the pulse generator and inductor in the form of an FET off line square wave generator with an impedance limited step up output transformer which is then applied to the full wave rectifier as before to yield a similar simmer current.

Steinkraus, Jr., Robert F. (Livermore, CA)

1994-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

Ionization tube simmer current circuit  

DOE Patents (OSTI)

A highly efficient flash lamp simmer current circuit utilizes a fifty percent duty cycle square wave pulse generator to pass a current over a current limiting inductor to a full wave rectifier. The DC output of the rectifier is then passed over a voltage smoothing capacitor through a reverse current blocking diode to a flash lamp tube to sustain ionization in the tube between discharges via a small simmer current. An alternate embodiment of the circuit combines the pulse generator and inductor in the form of an FET off line square wave generator with an impedance limited step up output transformer which is then applied to the full wave rectifier as before to yield a similar simmer current. 6 figures.

Steinkraus, R.F. Jr.

1994-12-13T23:59:59.000Z

42

Neutron And Gamma Detector Using An Ionization Chamber With An...  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron And Gamma Detector Using An Ionization Chamber Neutron And Gamma Detector Using An Ionization Chamber With An Integrated Body And Moderator A detector for detecting...

43

Photo double ionization of ethylene and acetylene near threshold  

E-Print Network (OSTI)

Photo double ionization of ethylene and acetylene nearcomplete measurements of the photo double ionization ofkinetic energy of the photo electrons and the nuclear

Gaire, B.

2014-01-01T23:59:59.000Z

44

Direct Experimental Observation of the Low Ionization Potentials...  

NLE Websites -- All DOE Office Websites (Extended Search)

Observation of the Low Ionization Potentials of Guanine in Free Oligonucleotides by Using Photoelectron Direct Experimental Observation of the Low Ionization Potentials of Guanine...

45

Photo double ionization of ethylene and acetylene near threshold  

E-Print Network (OSTI)

double ionization of ethylene and acetylene near thresholdphoto double ionization of ethylene (dou- ble CC bond) andsimilar yields of metastable ethylene dications produced by

Gaire, B.

2014-01-01T23:59:59.000Z

46

Applications of High-Resolution Electrospray Ionization Mass...  

NLE Websites -- All DOE Office Websites (Extended Search)

High-Resolution Electrospray Ionization Mass Spectrometry to Measurements of Average Oxygen to Carbon Ratios in Applications of High-Resolution Electrospray Ionization Mass...

47

Ambient Ionization Mass Spectrometry Analysis Pertaining To Biofuel Process Development.  

E-Print Network (OSTI)

??Mass spectrometry (MS) has undergone a revolution with the introduction of a new group of desorption/ionization (DI) techniques known collectively as Ambient Ionization mass spectrometry.… (more)

Dendukuri, Sushma

2012-01-01T23:59:59.000Z

48

Photo-Electric Ionization of Caesium Vapor  

Science Journals Connector (OSTI)

Measurement of photo-electric ionization in gases.—The current from a filament, normally limited by space change, is increased by the presence of positive ions. As shown by Kingdon this effect may be greatly magnified if a small cathode is practically enclosed by the anode so that the ions are imprisoned. This method was used for the detection of photo-electric ionization. Besides possessing extreme sensitivity it is unaffected by photo-electric emission from the electrodes.Photo-electric effect in caesium vapor.—The change in thermionic current with the unresolved radiation from a mercury arc was measured as functions of the applied voltage, filament temperature, and vapor pressure. Then the photo-electric effect as a function of wave-length was studied using a monochromatic illuminator to disperse light from the arc or a Mazda lamp. The ionization per unit flux was found to increase with increasing wave-length to a sharp maximum at the limit 1s=3184A of the principal series, as is required by the Bohr theory. For longer wave-lengths the ionization decreased to about 10 percent at 3400A. Photo-excitation. The simple theory does not admit of ionization by wave-lengths greater than 3184A but the data are in qualitative agreement with the hypothesis that such radiation produces excited atoms which upon collision with other atoms acquire sufficient additional energy to become ionized. Hence, unlike an x-ray limit, the photo-ionization effect for a valence electron is not sharply discontinuous at the true threshold for direct ionization.Photo-ionization photometer and intensitometer. A tube of the type described, with suitable gases for the range of wave-length involved, may be used as a photometer or may be calibrated to measure intensity of radiation directly.

Paul D. Foote and F. L. Mohler

1925-08-01T23:59:59.000Z

49

Neutron-proton pairing reexamined  

Science Journals Connector (OSTI)

We reexamine neutron-proton pairing as a phenomenon that should be explainable in a microscopic theory of nuclear binding energies. Empirically, there is an increased separation energy when both neutron and proton numbers are even or if they are both odd. The enhancement is present at some level in nearly all nuclei: the separation energy difference has the opposite sign in less than 1% of the cases in which sufficient data exist. We discuss the possible origin of the effect in the context of density functional theory (DFT) and its extensions. Neutron-proton pairing from mean-field theory does not seem promising to explain the effect. Gao and Chen have argued that a significant part of the increased binding in odd-odd deformed nuclei might arise as a recoupling energy, and we find a similar result for spherical nuclei. This suggests that the DFT should be extended by angular momentum projection to reach an accuracy capable of treating this effect.

W. A. Friedman and G. F. Bertsch

2007-11-07T23:59:59.000Z

50

Non-empirical pairing functional  

E-Print Network (OSTI)

The present contribution reports the first systematic finite-nucleus calculations performed using the Energy Density Functional method and a non-empirical pairing functional derived from low-momentum interactions. As a first step, the effects of Coulomb and the three-body force are omitted while only the bare two-nucleon interaction at lowest order is considered. To cope with the finite-range and non-locality of the bare nuclear interaction, the 1S0 channel of Vlowk is mapped onto a convenient operator form. For the first time, neutron-neutron and proton-proton pairing correlations generated in finite nuclei by the direct term of the two-nucleon interaction are characterized in a systematic manner. Eventually, such predictions are compared to those obtained from empirical local functionals derived from density-dependent zero range interactions. The characteristics of the latter are analyzed in view of that comparison and a specific modification of their isovector density dependence is suggested to accommodate Coulomb effects and the isovector trend of neutron gaps at the same time.

T. Duguet; T. Lesinski

2007-12-07T23:59:59.000Z

51

Ionization threshold of crystalline LiF  

Science Journals Connector (OSTI)

The ionization threshold for crystalline LiF is calculated using a cluster embedded model. The experimental ionization threshold is 9.8 eV; however, previous band and cluster model calculations gave 14–15 eV. These earlier calculations used a crystal having a perfect lattice. In the present work, a crystal with lattice defects is introduced. The calculated surface and bulk ionization thresholds are 8.1 and 8.7 eV, respectively, showing good correspondence with experiment. The electron affinity and other band parameters are also studied.

Hiroshi Tatewaki

1999-08-01T23:59:59.000Z

52

Nonlinearities in Flame Ionization Detector Response  

Science Journals Connector (OSTI)

......ionization detector (FIO) to various hydrocarbons hat been found to be proportional to powers of the concentration which ex- ceed unity In certain ranges. The sample elution rates at which this effect is observed and operating condi- tions employed correspond......

J.H. Bromly; P. Roga

1980-11-01T23:59:59.000Z

53

6 - Industrial Applications of Ionizing Radiation  

Science Journals Connector (OSTI)

The chapter summarizes the industrial applications of ionizing radiation. Ionizing radiation finds use in a variety of industrial applications such as wire and cable insulation, tire manufacturing, production of polymeric foams, heat-shrinkable films and tubings, curing of coatings, adhesives and composites, printing, and other technological development. It provides extensive information on EB process in wire and cable and tire technology. The chapter also provides discussion on EB process in the manufacture of polyolefin foams and heat-shrinkable materials. Detailed discussion on cross-linked PE pipes (PEX) including methods for production, irradiation, and its advantages, is presented. Other applications for ionizing radiation include sterilization of medical devices, hydrogels, radiation curing of polymeric composites, production of fluoroadditives, radiation-cured flexography, coatings, adhesives, paints, and printing inks. Keywords Ionizing radiation; tire manufacturing; wire and cable insulations; printing inks; polyolefin foams; heat-shrinkable materials; cross-linked PE pipes (PEX); hydrogels; flexography

Jiri George Drobny

2013-01-01T23:59:59.000Z

54

Electrical conductivity of nondegenerate, fully ionized plasmas  

Science Journals Connector (OSTI)

Within a virial expansion of the electrical conductivity of a fully ionized plasma, which takes into account many-particle effects, different limiting cases are considered. An appropriate interpolation formula is compared with experimental values.

G. Röpke and R. Redmer

1989-01-15T23:59:59.000Z

55

Impact ionization in GaAs: A screened exchange density-functional approach  

SciTech Connect

Results are presented of a fully ab initio calculation of impact ionization rates in GaAs within the density functional theory framework, using a screened-exchange formalism and the highly precise all-electron full-potential linearized augmented plane wave method. The calculated impact ionization rates show a marked orientation dependence in k space, indicating the strong restrictions imposed by the conservation of energy and momentum. This anisotropy diminishes as the impacting electron energy increases. A Keldysh type fit performed on the energy-dependent rate shows a rather soft edge and a threshold energy greater than the direct band gap. The consistency with available Monte Carlo and empirical pseudopotential calculations shows the reliability of our approach and paves the way to ab initio calculations of pair production rates in new and more complex materials.

Picozzi, S., Asahi, R., Geller, C.B., Continenza, A., and Freeman, A.J.

2001-08-13T23:59:59.000Z

56

IONIZATION IN ATMOSPHERES OF BROWN DWARFS AND EXTRASOLAR PLANETS. V. ALFVÉN IONIZATION  

SciTech Connect

Observations of continuous radio and sporadic X-ray emission from low-mass objects suggest they harbor localized plasmas in their atmospheric environments. For low-mass objects, the degree of thermal ionization is insufficient to qualify the ionized component as a plasma, posing the question: what ionization processes can efficiently produce the required plasma that is the source of the radiation? We propose Alfvén ionization as a mechanism for producing localized pockets of ionized gas in the atmosphere, having sufficient degrees of ionization (?10{sup –7}) that they constitute plasmas. We outline the criteria required for Alfvén ionization and demonstrate its applicability in the atmospheres of low-mass objects such as giant gas planets, brown dwarfs, and M dwarfs with both solar and sub-solar metallicities. We find that Alfvén ionization is most efficient at mid to low atmospheric pressures where a seed plasma is easier to magnetize and the pressure gradients needed to drive the required neutral flows are the smallest. For the model atmospheres considered, our results show that degrees of ionization of 10{sup –6}-1 can be obtained as a result of Alfvén ionization. Observable consequences include continuum bremsstrahlung emission, superimposed with spectral lines from the plasma ion species (e.g., He, Mg, H{sub 2}, or CO lines). Forbidden lines are also expected from the metastable population. The presence of an atmospheric plasma opens the door to a multitude of plasma and chemical processes not yet considered in current atmospheric models. The occurrence of Alfvén ionization may also be applicable to other astrophysical environments such as protoplanetary disks.

Stark, C. R.; Helling, Ch.; Rimmer, P. B. [SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS (United Kingdom); Diver, D. A., E-mail: craig.stark@st-andrews.ac.uk [SUPA, School of Physics and Astronomy, Kelvin Building, University of Glasgow, Glasgow, G12 8QQ (United Kingdom)

2013-10-10T23:59:59.000Z

57

Magnetism and pairing in Hubbard bilayers  

Science Journals Connector (OSTI)

We study the Hubbard model on a bilayer with repulsive on-site interactions U in which fermions undergo both intraplane (t) and interplane (tz) hopping. This situation is what one would expect in high-temperature superconductors such as YBa2Cu3O7-y, with two adjacent CuO2 planes. Magnetic and pairing properties of the system are investigated through quantum Monte Carlo simulations for both half- and quarter-filled bands. We find that in all cases interplanar pairing with dx2-z2 symmetry is dominant over planar pairing with dx2-y2 symmetry, and that for a large enough tz pair formation is possible through antiferromagnetic correlations. However, another mechanism is needed to make these pairs condense into a superconducting state at lower temperatures. We identify the temperature for pair formation with the spin-gap crossover temperature.

Raimundo R. dos Santos

1995-06-01T23:59:59.000Z

58

Pairing Effects in Nuclear Fusion Reaction  

E-Print Network (OSTI)

We simulate a heavy-ion collision using the canonical-basis time-dependent Hartree-Fock-Bogoliubov theory (Cb-TDHFB) treating pairing correlation in the three-dimensional coordinate space. We apply the Cb-TDHFB to 22O+22O collision with a contact-type pairing energy functional, and compare results of Cb-TDHFB and TDHF to investigate the effects of pairing correlations in nuclear fusion. Our results seem to indicate that pairing effects do not increase the fusion cross section in this system.

Ebata, Shuichiro

2013-01-01T23:59:59.000Z

59

Using audio in secure device pairing  

Science Journals Connector (OSTI)

Secure pairing of electronic devices is an important issue that must be addressed in many contexts. In the absence of prior security context, the need to involve the user in the pairing process is a prominent challenge. In this paper, we investigate the use of the audio channel for human-assisted device pairing. First we assume a common (insecure) wireless channel between devices. We then obviate the assumption of a pre-existing common channel with a single-channel device pairing approach only based on audio. Both approaches are applicable to a wide range of devices and place light burden on the user.

Michael T. Goodrich; Michael Sirivianos; John Solis; Claudio Soriente; Gene Tsudik; Ersin Uzun

2009-01-01T23:59:59.000Z

60

Multiphoton ionization of large water clusters  

SciTech Connect

Water clusters are multimers of water molecules held together by hydrogen bonds. In the present work, multiphoton ionization in the UV range coupled with time of flight mass spectrometry has been applied to water clusters with up to 160 molecules in order to obtain information on the electronic states of clusters of different sizes up to dimensions that can approximate the bulk phase. The dependence of ion intensities of water clusters and their metastable fragments produced by laser ionization at 355 nm on laser power density indicates a (3+1)-photon resonance-enhanced multiphoton ionization process. It also explains the large increase of ionization efficiency at 355 nm compared to that at 266 nm. Indeed, it was found, by applying both nanosecond and picosecond laser ionization with the two different UV wavelengths, that no water cluster sequences after n = 9 could be observed at 266 nm, whereas water clusters up to m/z 2000 Th in reflectron mode and m/z 3000 Th in linear mode were detected at 355 nm. The agreement between our findings on clusters of water, especially true in the range with n > 10, and reported data for liquid water supports the hypothesis that clusters above a critical dimension can approximate the liquid phase. It should thus be possible to study clusters just above 10 water molecules, for getting information on the bulk phase structure.

Apicella, B., E-mail: apicella@irc.cnr.it [Combustion Research Institute, IRC–C.N.R., P.le Tecchio 80, 80125 Napoli (Italy); Li, X. [Key Laboratory of Power Machinery and Engineering, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240 (China); Passaro, M. [CNISM and Chemical Engineering, Materials and Industrial Production Department, University of Naples “Federico II,” P.le Tecchio 80, 80125 Napoli (Italy); Spinelli, N. [CNISM and Physics Department, University of Naples “Federico II,” Via Cintia, 80124 Napoli (Italy); Wang, X. [SPIN–C.N.R., Via Cintia, 80124 Napoli (Italy)

2014-05-28T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

MUCOOL: Ionization Cooling R&D  

NLE Websites -- All DOE Office Websites (Extended Search)

Laboratory Laboratory MUCOOL Muon Ionization Cooling R&D Welcome to the muon ionization cooling experimental R&D page. The MuCool collaboration has been formed to pursue the development of a muon ionization cooling channel for a high luminosity muon collider. For more information please contact Alan Bross (Spokesperson: bross@fnal.gov), Rick Fernow (BNL Contact person: fernow1@bnl.gov), or Mike Zisman (LBNL Contact person: mszisman@lbl.gov). General MUCOOL Telephone Book MUCOOL Notes MUCOOL Collaborating Institutes and Interests Useful Links Link to IIT MUCOOL page Meetings Muon Collaboration Friday Meetings Fermilab Muon Group Monday Meetings MTA RF Workshop (August 22, 2007 - Fermilab) Low Emittance Muon Collider Workshop (February 12-16, 2007, Fermilab) Low Emittance Muon Collider Workshop (February 6-10, 2006, Fermilab)

62

Weak interaction studies using resonance ionization spectroscopy  

SciTech Connect

Important developments in laser sources for the vacuum ultraviolet (VUV) region of the spectrum are making it possible to carry out resonance ionization of some of the noble gases. It has already been shown that xenon can be ionized in a two-photon allowed excitation from the ground state. Recently a new method of generating radiation by four-wave mixing in mercury vapor enables excitation of xenon in a one-photon resonance process. With these new laser sources we expect to have effective ionization volumes of 10/sup -3/ to 10/sup -2/ cm/sup 3/ for the cases of argon, krypton, and xenon. This has important consequences in weak interaction physics and environmental research.

Payne, M.G.; Hurst, G.S.

1982-01-01T23:59:59.000Z

63

Removal of submicron particles using a carbon fiber ionizer-assisted medium air filter in a heating, ventilation, and air-conditioning (HVAC) system  

Science Journals Connector (OSTI)

Laboratory tests of particle removal were performed with a pair of carbon fiber ionizers installed upstream of a glass fiber air filter. For air flow face velocities of 0.4, 0.6, and 0.8 m/s, the overall particle removal efficiencies of the filter for all submicron particles were 17%, 16%, and 14%, respectively, when the ionizers were not turned on. These values increased to 27%, 23%, and 19%, respectively, when the ionizers were used to generate ions of 6.0 × 109 ions/cm3 in concentration. The carbon fiber ionizers were then installed in front of a glass fiber air filter located in a heating, ventilation, and air-conditioning (HVAC) system. Field tests were performed in a test office room with a total indoor particle concentration of 2.2 × 104 particles/cm3. When the flow rate was 75 cubic meters per hour (CMH), the steady-state values of the total indoor particle concentrations using the glass fiber air filter with and without ionizers decreased to 0.87 × 104 particles/cm3 and 1.15 × 104 particles/cm3, respectively, resulting in a 25% decrease of the ionizer effect. When the operation flow rate was increased to 115 and 150 CMH, the effect of the ionizer decreased to 19% and 17%, respectively. These experimental data match the results calculated using a mass-balance model whose parameters were determined from laboratory tests.

Jae Hong Park; Ki Young Yoon; Jungho Hwang

2011-01-01T23:59:59.000Z

64

Progress on a Cavity with Beryllium Walls for Muon Ionization Cooling Channel R&D.  

E-Print Network (OSTI)

WITH BERYLLIUM WALLS FOR MUON IONIZATION COOLING CHANNELNY 11973, USA Abstract The Muon Accelerator Program (MAP)an ionization cooling channel for muon beams. An ionization

Bowring, D.L.

2014-01-01T23:59:59.000Z

65

Composite scintillators for detection of ionizing radiation  

DOE Patents (OSTI)

Applicant's present invention is a composite scintillator having enhanced transparency for detecting ionizing radiation comprising a material having optical transparency wherein said material comprises nano-sized objects having a size in at least one dimension that is less than the wavelength of light emitted by the composite scintillator wherein the composite scintillator is designed to have selected properties suitable for a particular application.

Dai, Sheng (Knoxville, TN) [Knoxville, TN; Stephan, Andrew Curtis (Knoxville, TN) [Knoxville, TN; Brown, Suree S. (Knoxville, TN) [Knoxville, TN; Wallace, Steven A. (Knoxville, TN) [Knoxville, TN; Rondinone, Adam J [Knoxville, TN

2010-12-28T23:59:59.000Z

66

Salt Tolerance of Desorption Electrospray Ionization (DESI)  

SciTech Connect

Suppression of ion intensity in the presence of high salt matrices is common in most mass spectrometry ionization techniques. Desorption electrospray ionization (DESI) is an ionization method that exhibits salt tolerance, and this is investigated. DESI analysis was performed on three different drug mixtures in the presence of 0, 0.2, 2, 5, 10, and 20% NaCl:KCl weight by volume from seven different surfaces. At physiological concentrations individual drugs in each mixture were observed with each surface. Collision-induced dissociation (CID) was used to provide additional confirmation for select compounds. Multiple stage experiments, to MS5, were performed for select compounds. Even in the absence of added salt, the benzodiazepine containing mixture yielded sodium and potassium adducts of carbamazepine which masked the ions of interest. These adducts were eliminated by adding 0.1% 7M ammonium acetate to the standard methanol:water (1:1) spray solvent. Comparison of the salt tolerance of DESI with that of electrospray ionization (ESI) demonstrated much better signal/noise characteristics for DESI in this study. The salt tolerance of DESI was also studied by performing limit of detection and dynamic range experiments. Even at a salt concentration significantly above physiological concentrations, select surfaces were effective in providing spectra that allowed the ready identification of the compounds of interest. The already high salt tolerance of DESI can be optimized further by appropriate choices of surface and spray solution.

Jackson, Ayanna U. [Purdue University; Talaty, Nari [Purdue University; Cooks, R G [Purdue University; Van Berkel, Gary J [ORNL

2007-01-01T23:59:59.000Z

67

Muon Cooling via Ionization Andrea Kay Forget  

E-Print Network (OSTI)

1 Muon Cooling via Ionization Andrea Kay Forget Department of Physics, Wayne State University, Detroit, Michigan 48202 Dated: August 7, 2006 Muons only live a few microseconds before they ultimately, and laser cooling) cannot be used to properly cool muons that are being used in proposed accelerators

Cinabro, David

68

Studies of Anomalous Ionization Edgar Y. Choueiri  

E-Print Network (OSTI)

Laboratory (EPPDyL) Princeton University, Princeton NJ 08544. Hideo Okuda Princeton Plasma Physics LabStudies of Anomalous Ionization Edgar Y. Choueiri Electric Propulsion and Plasma Dynamics., Princeton University Princeton, NJ. 08544 AIAA Paper: AIAA-94-2465 Abstract In order to improve the accuracy

Choueiri, Edgar

69

Detoxification of Salmonella typhimurium Lipopolysaccharide by Ionizing Radiation  

Science Journals Connector (OSTI)

...efficiency of ionizing radiation in detoxifying...decreased with doses above 1 Mrad...efficiency of ionizing radiation in detoxifying...decreased with doses above 1 Mrad...the visible range. After radiation, the general...radiation doses through 20...

Joseph J. Previte; Y. Chang; H. M. El-Bisi

1967-05-01T23:59:59.000Z

70

Oligonucleotide microarray analysis of low-dose ionizing radiation exposure  

Science Journals Connector (OSTI)

...health risk due to low-dose ionizing radiation is still debated. Functional...pathways that are induced by ionizing irradiation (IR...transcriptionally regulated by low-dose IR in occupationally...and showed different ranges of accumulated doses...

Paola Silingardi; Elena Morandi; Cinzia Severini; Daniele Quercioli; Monica Vaccari; Wolfango Horn; Maria Concetta Nucci; Vittorio Lodi; Francesco Violante; Sandro Grilli; and Annmaria Colacci

2007-05-01T23:59:59.000Z

71

Ionizing Radiation Activates the Nrf2 Antioxidant Response  

Science Journals Connector (OSTI)

...Scientific). Results Ionizing radiation does not activate ARE-reporter...determine if exposure to varying doses of ionizing radiation would activate the Nrf2-ARE pathway. The radiation dose range was extended below that used...

J. Tyson McDonald; Kwanghee Kim; Andrew J. Norris; Erina Vlashi; Tiffany M. Phillips; Chann Lagadec; Lorenza Della Donna; Josephine Ratikan; Heather Szelag; Lynn Hlatky; and William H. McBride

2010-11-01T23:59:59.000Z

72

Observation of a small oligonucleotide duplex by electrospray ionization mass spectrometry  

SciTech Connect

Electrospray ionization (ESI) has been demonstrated to be a soft ionization technique, allowing accurate molecular weight determination for biopolymers due to gas-phase multiple charging. Recent results have demonstrated that noncovalent associations can be preserved upon transfer into the gas phase with ESI, providing a new approach to the determination of both structurally-specific and nonspecific noncovalent associations in solution. The mass spectrometric experimental conditions necessary to preserve such noncovalent associations, and the physical constraints upon such, have yet to be elucidated, although it is clear that gentle interface conditions minimizing internal excitation of noncovalent complexes are helpful. Base-paired oligonucleotide hybridization constitutes one of the most important and thoroughly studied noncovalent associations of biopolymers. Initial attempts to observe duplex oligonucleotides resulted in detection of only the monomeric constituents. Since then, the authors have developed interface conditions that are more gentle and yet still provide sufficient molecular ion desolvation to preserve such associations using new instrumentation with a greatly extended m/z range. In this communication, the authors report the successful ionization of duplex oligonucleotides and the conditions necessary for detection by negative ion ESI-MS. 6 refs., 1 fig.

Light-Wahl, K.J.; Springer, D.L.; Winger, B.E.; Edmonds, C.G.; Thrall, B.D.; Smith, R.D. (Pacific Northwest Lab., Richland, WA (United States)); Camp, D.G. II (Eastern Oregon State College, La Grande (United States))

1993-01-27T23:59:59.000Z

73

Order-Sorted Dependency Pairs Salvador Lucas  

E-Print Network (OSTI)

Order-Sorted Dependency Pairs Salvador Lucas DSIC, Universidad Polit´ecnica de Valencia, Spain modeled as many-sorted or, more Salvador Lucas was partially supported by the EU (FEDER) and the Spanish

Lucas, Salvador

74

Schwinger pair creation in multilayer graphene  

E-Print Network (OSTI)

The low energy effective field model for the multilayer graphene (at ABC stacking) in external Electric field is considered. The Schwinger pair creation rate and the vacuum persistence probability are calculated using the semi - classical approach.

M. A. Zubkov

2012-03-31T23:59:59.000Z

75

90 Seconds of Discovery: Frustrated Lewis Pairs  

SciTech Connect

Hydrogen activating catalysts play an important role in producing valuable chemicals, such as biofuels and ammonia. As a part of efforts to develop the next generation of these catalysts, PNNL researchers have found potential in Frustrated Lewis Pairs.

Kathmann, Shawn; Schenter, Greg; Autrey, Tom

2014-02-14T23:59:59.000Z

76

Continuous-wave, pair-pumped laser  

SciTech Connect

We report room-temperature operation of what we believe is the first continuous-wave laser that relies exclusively on cooperative upconversion by coupled ion pairs to achieve population inversion.

Xie, P.; Rand, S.C. (Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, MI (USA))

1990-08-01T23:59:59.000Z

77

Photo-Ionization and the Electrical Breakdown of Gases  

Science Journals Connector (OSTI)

25 June 1953 research-article Photo-Ionization and the Electrical Breakdown...theoretical investigation is made of the role of photo-ionization of the gas in the development...obtained experimentally. It is shown that photo-ionization can lead to electrical breakdown...

1953-01-01T23:59:59.000Z

78

Epidemiological Studies of Leukemia in Persons Exposed to Ionizing Radiation  

Science Journals Connector (OSTI)

...exposed to ionizing radiation, the author...the higher dose range regardless...low dose range, it is emphasized...possibility of radiation hazards existing at low doses should not...exposed to ionizing radiation...exposed to ionizing radiation, the author...the higher dose range regardless...

L. H. Hempelmann

1960-01-01T23:59:59.000Z

79

Critical Behavior of Electron Impact Ionization of Atoms  

E-Print Network (OSTI)

Critical Behavior of Electron Impact Ionization of Atoms IMAD LADADWA,1,2 SABRE KAIS1 1 Department of the electron impact ionization for different atoms are calculated numerically in the Born approximation as a function of both the incident electron energy and the nuclear charge Z of the ionized atom. We show

Kais, Sabre

80

Two pairing parameters in superconducting grains  

Science Journals Connector (OSTI)

Unlike bulk superconductivity, where one energy scale, the energy gap, characterizes pairing correlations, we show that in small superconducting grains there exist two different such quantities. The first characterizes collective properties of the grain, such as the condensation energy, and the second single-particle properties. To describe these two energy scales, we define two corresponding pairing parameters, and show that although both reduce to the bulk gap for large grains, this occurs at different size scales.

M. Schechter; J. von Delft; Y. Imry; Y. Levinson

2003-02-27T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

A numerical scheme for ionizing shock waves  

SciTech Connect

A two-dimensional (2D) visual computer code to solve the steady state (SS) or transient shock problems including partially ionizing plasma is presented. Since the flows considered are hypersonic and the resulting temperatures are high, the plasma is partially ionized. Hence the plasma constituents are electrons, ions and neutral atoms. It is assumed that all the above species are in thermal equilibrium, namely, that they all have the same temperature. The ionization degree is calculated from Saha equation as a function of electron density and pressure by means of a nonlinear Newton type root finding algorithms. The code utilizes a wave model and numerical fluctuation distribution (FD) scheme that runs on structured or unstructured triangular meshes. This scheme is based on evaluating the mesh averaged fluctuations arising from a number of waves and distributing them to the nodes of these meshes in an upwind manner. The physical properties (directions, strengths, etc.) of these wave patterns are obtained by a new wave model: ION-A developed from the eigen-system of the flux Jacobian matrices. Since the equation of state (EOS) which is used to close up the conservation laws includes electronic effects, it is a nonlinear function and it must be inverted by iterations to determine the ionization degree as a function of density and temperature. For the time advancement, the scheme utilizes a multi-stage Runge-Kutta (RK) algorithm with time steps carefully evaluated from the maximum possible propagation speed in the solution domain. The code runs interactively with the user and allows to create different meshes to use different initial and boundary conditions and to see changes of desired physical quantities in the form of color and vector graphics. The details of the visual properties of the code has been published before (see [N. Aslan, A visual fluctuation splitting scheme for magneto-hydrodynamics with a new sonic fix and Euler limit, J. Comput. Phys. 197 (2004) 1-27]). The two-dimensional nature of ION-A was presented by a planar shock wave propagating over a circular obstacle. It was demonstrated that including the effects of ionization in calculating complex flows is important, even when they appear initially negligible. This code can be used to accurately simulate the nonlinear time dependent evolution of neutral or ionized plasma flows from supersonic to hypersonic regimes.

Aslan, Necdet [Yeditepe University, Physics Department, Kayisda g-circumflex i, 34755 Istanbul (Turkey)]. E-mail: naslan@yeditepe.edu.tr; Mond, Michael [Ben Gurion University, Mechanical Engineering Department, Beer Sheva (Israel)

2005-12-10T23:59:59.000Z

82

Nuclear elements in Banach Jordan pairs Ottmar Loos  

E-Print Network (OSTI)

Nuclear elements in Banach Jordan pairs Ottmar Loos Abstract We introduce nuclear elements in Banach Jordan pairs, generalizing the nuclear elements Jordan pairs and show that the trace form Trintroduced in [3] may be extended to the nuclear

83

E-Print Network 3.0 - assisted resonance ionization Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

ionization PADIACplasma43 Dielectricbarrierdischarge... Matrix-assisted ionization ... Source: Oak Ridge National Laboratory Fossil Energy Program Collection: Fossil Fuels 28...

84

Photo-Ionization of Molecules near Threshold  

Science Journals Connector (OSTI)

An orthogonalized Coulomb-wave method for the construction of continuum wave functions of molecules is described. Hydrogenic functions of definite angular momentum, which transform according to the irreducible representations of the point group of the molecule, are phenomenologically used as trial functions. Corrections to the trial functions are made by orthogonalizing them to charge rearrangement states of the molecule. The photo-ionization cross section is obtained by summing over the asymptotic angular-momentum quantum number. The method is exemplified by calculation of the photo-ionization cross sections of the ground and first excited states of the anthracene molecule in the range of 1.5 eV above threshold.

John P. Hernandez

1968-03-05T23:59:59.000Z

85

Photo-Auger ionization of lithiumlike ions  

Science Journals Connector (OSTI)

The photo-Auger ionization process is a higher-order contribution to the direct photoelectric effect in which photoexcitation of an inner-shell electron is followed by the emission of an Auger electron. The frequency-integrated photo-Auger ionization cross section for ions of the lithium isoelectronic sequence is calculated in the isolated resonance approximation. The effects of transitions into all accessible intermediate states are explicitly included. Results are compared with the frequency-integrated direct photoionization cross section. The relative contribution of the photo-Auger effect for three-electron ions is a maximum in the Ne(7 +) region, where it is of order 70% of the direct process.

K. J. LaGattuta and Yukap Hahn

1982-01-01T23:59:59.000Z

86

External ionization mechanisms for advanced thermionic converters  

SciTech Connect

This work investigates ion generation and recombination mechanisms in the cesium plasma as they pertain to the advanced mode thermionic energy converter. The changes in plasma density and temperature within the converter have been studied under the influence of several promising auxiliary ionization candidate sources. Three novel approaches of external cesium ion generation have been investigated in some detail, namely vibrationally excited N/sub 2/ as are energy source of ionization of Cs ions in a dc discharge, microwave power as a means of resonant sustenance of the cesium plasma, and ion generation in a pulse N/sub 2/-Cs mixture. The experimental data obtained and discussed in this work show that all three techniques - i.e. the non-LTE high-voltage pulsing, the energy transfer from vibrationally excited diatomic gases, and the external pumping with a microwave power - have considerable promise as schemes in auxiliary ion generation applicable to the advanced thermionic energy converter.

Hatziprokopiou, M.E.

1981-01-01T23:59:59.000Z

87

Photo-Ionization of Crystalline Anthracene  

Science Journals Connector (OSTI)

The photo-ionization spectra of the ground, first singlet, and first triplet states of crystalline anthracene are calculated assuming transitions to a simple continuum. The calculations neglect vibrational-overlap factors which will reduce the cross sections perhaps by as much as a factor of 10. Recombination is also neglected, and is blamed for discrepancies between the calculation and experiments which measure photo-currents. Kepler has reported a cross section of 2×10-19 cm2 from the first singlet, Courtens et al., one of 0.6×10-19; the calculation gives 6×10-18. Holzman et al. report 10-20 cm2 from the first triplet; the calculation gives 6×10-18. If one accounted for vibrational overlap and recombination (which will be larger in the second experiment, because of the smaller kinetic energy), the agreement would be good. The agreement is not so good with the magnitude of transitions from the ground state, though the energy dependence gives a good fit. The discrepancy may be due to the (neglected) influence of auto-ionizing states on the final-state wave functions. Based on a theory by Choi, the singlet exciton-exciton ionization rate constant is calculated to be 2×10-9 cm3 sec-1 (vibrations and recombination neglected) compared with Silver's experimental value of 0.8×10-10; again the agreement is good. Finally, the time needed for a photo-ionized electron to lose kinetic energy by exciting a triplet is calculated to be 10-9 sec or longer, so this mechanism is ruled out as an energy-loss process in comparison with the emission of optical vibrations, which has been estimated to take about 10-13 sec.

John P. Hernandez

1968-05-15T23:59:59.000Z

88

Ab Initio Atomic Simulations of Antisite Pair Recovery in Cubic...  

NLE Websites -- All DOE Office Websites (Extended Search)

Atomic Simulations of Antisite Pair Recovery in Cubic Silicon Carbide. Ab Initio Atomic Simulations of Antisite Pair Recovery in Cubic Silicon Carbide. Abstract: The thermal...

89

The multiphoton ionization of uranium hexafluoride  

SciTech Connect

Multiphoton ionization (MPI) time-of-flight mass spectroscopy and photoelectron spectroscopy studies of UF{sub 6} have been conducted using focused light from the Nd:YAG laser fundamental ({lambda}=1064 nm) and its harmonics ({lambda}=532, 355, or 266 nm), as well as other wavelengths provided by a tunable dye laser. The MPI mass spectra are dominated by the singly and multiply charged uranium ions rather than by the UF{sub x}{sup +} fragment ions even at the lowest laser power densities at which signal could be detected. The laser power dependence of U{sup n+} ions signals indicates that saturation can occur for many of the steps required for their ionization. In general, the doubly-charged uranium ion (U{sup 2+}) intensity is much greater than that of the singly-charged uranium ion (U{sup +}). For the case of the tunable dye laser experiments, the U{sup n+} (n = 1- 4) wavelength dependence is relatively unstructured and does not show observable resonance enhancement at known atomic uranium excitation wavelengths. The dominance of the U{sup 2+} ion and the absence or very small intensities of UF{sub x}{sup +} fragments, along with the unsaturated wavelength dependence, indicate that mechanisms may exist other than ionization of bare U atoms after the stepwise photodissociation of F atoms from the parent molecule.

Armstrong, D.P. (Oak Ridge K-25 Site, TN (United States). UEO Enrichment Technical Operations Div.) [Oak Ridge K-25 Site, TN (United States). UEO Enrichment Technical Operations Div.

1992-05-01T23:59:59.000Z

90

Ionization photophysics and spectroscopy of dicyanoacetylene  

SciTech Connect

Photoionization of dicyanoacetylene was studied using synchrotron radiation over the excitation range 8–25 eV, with photoelectron-photoion coincidence techniques. The absolute ionization cross-section and detailed spectroscopic aspects of the parent ion were recorded. The adiabatic ionization energy of dicyanoacetylene was measured as 11.80 ± 0.01 eV. A detailed analysis of the cation spectroscopy involves new aspects and new assignments of the vibrational components to excitation of the quasi-degenerate A{sup 2}?{sub g}, B{sup 2}?{sub g}{sup +} states as well as the C{sup 2}?{sub u}{sup +} and D{sup 2}?{sub u} states of the cation. Some of the structured autoionization features observed in the 12.4–15 eV region of the total ion yield spectrum were assigned to vibrational components of valence shell transitions and to two previously unknown Rydberg series converging to the D{sup 2}?{sub u} state of C{sub 4}N{sub 2}{sup +}. The appearance energies of the fragment ions C{sub 4}N{sup +}, C{sub 3}N{sup +}, C{sub 4}{sup +}, C{sub 2}N{sup +}, and C{sub 2}{sup +} were measured and their heats of formation were determined and compared with existing literature values. Thermochemical calculations of the appearance potentials of these and other weaker ions were used to infer aspects of dissociative ionization pathways.

Leach, Sydney, E-mail: Sydney.Leach@obspm.fr, E-mail: Martin.Schwell@lisa.u-pec.fr; Champion, Norbert [LERMA UMR CNRS 8112, Observatoire de Paris-Meudon, 5 place Jules-Jansen, 92195 Meudon (France)] [LERMA UMR CNRS 8112, Observatoire de Paris-Meudon, 5 place Jules-Jansen, 92195 Meudon (France); Schwell, Martin, E-mail: Sydney.Leach@obspm.fr, E-mail: Martin.Schwell@lisa.u-pec.fr; Bénilan, Yves; Fray, Nicolas; Gazeau, Marie-Claire [LISA UMR CNRS 7583, Université Paris-Est Créteil and Université Paris Diderot, Institut Pierre Simon Laplace, 61 Avenue du Général de Gaulle, 94010 Créteil (France)] [LISA UMR CNRS 7583, Université Paris-Est Créteil and Université Paris Diderot, Institut Pierre Simon Laplace, 61 Avenue du Général de Gaulle, 94010 Créteil (France); Garcia, Gustavo A.; Gaie-Levrel, François [Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, B.P. 48, 91192 Gif-sur-Yvette Cedex (France)] [Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, B.P. 48, 91192 Gif-sur-Yvette Cedex (France); Guillemin, Jean-Claude [Institut des Sciences Chimiques de Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7 (France)] [Institut des Sciences Chimiques de Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7 (France)

2013-11-14T23:59:59.000Z

91

Thermodynamics of pairing in mesoscopic systems  

E-Print Network (OSTI)

Using numerical and analytical methods implemented for different models we conduct a systematic study of thermodynamic properties of pairing correlation in mesoscopic nuclear systems. Various quantities are calculated and analyzed using the exact solution of pairing. An in-depth comparison of canonical, grand canonical, and microcanonical ensemble is conducted. The nature of the pairing phase transition in a small system is of a particular interest. We discuss the onset of discontinuity in the thermodynamic variables, fluctuations, and evolution of zeros of the canonical and grand canonical partition functions in the complex plane. The behavior of the Invariant Correlational Entropy is also studied in the transitional region of interest. The change in the character of the phase transition due to the presence of magnetic field is discussed along with studies of superconducting thermodynamics.

Tony Sumaryada; Alexander Volya

2007-06-12T23:59:59.000Z

92

Holographic EPR Pairs, Wormholes and Radiation  

E-Print Network (OSTI)

As evidence for the ER=EPR conjecture, it has recently been observed that the string that is holographically dual to an entangled quark-antiquark pair separating with (asymptotically) uniform acceleration has a wormhole on its worldsheet. We point out that a two-sided horizon and a wormhole actually appear for much more generic quark-antiquark trajectories, which is consistent with the fact that the members of an EPR pair need not be permanently out of causal contact. The feature that determines whether the causal structure of the string worldsheet is trivial or not turns out to be the emission of gluonic radiation by the dual quark and antiquark. In the strongly-coupled gauge theory, it is only when radiation is emitted that one obtains an unambiguous separation of the pair into entangled subsystems, and this is what is reflected on the gravity side by the existence of the worldsheet horizon.

Chernicoff, Mariano; Pedraza, Juan F

2013-01-01T23:59:59.000Z

93

Probing light stop pairs at the LHC  

Science Journals Connector (OSTI)

In this work, we study the light stop pair signals at the LHC. We explore the supersymmetry parameter space with nonuniversal gaugino and third-generation masses at the grand unified theory scale. Recent LHC supersymmetry search results based on 35??pb-1 and 1??fb-1 of data are implemented to put the limits on stop pair events. The dark matter relic density and direct detection constraints are also taken into account. Detailed simulations on the signals and background for some benchmark points are performed, and it is found that the stop pair signals usually escape the LHC search if the present cut conditions are used. We also explore the potential and sensitivity of ILC to probe such scenarios. It is found that the ILC can detect them with an integrated luminosity of a few tens of fb-1.

Xiao-Jun Bi; Qi-Shu Yan; Peng-Fei Yin

2012-02-07T23:59:59.000Z

94

Comparative PCET Study of a Donor?Acceptor Pair Linked by Ionized and Nonionized Asymmetric Hydrogen-Bonded Interfaces  

E-Print Network (OSTI)

A Zn(II) amidinium porphyrin is the excited-state electron donor (D) to a naphthalene diimide acceptor (A) appended with either a carboxylate or sulfonate functionality. The two-point hydrogen bond (···[H[superscript +

Young, Elizabeth R.

95

Project-Role Pair user_tokens  

E-Print Network (OSTI)

OSAC Users (U) Domains (D) Roles (R) User Assignment (UA) Permission Assignment (PA) Project Ownership (PO) Project-Role Pair (PRP) Projects (P) Tokens (T) User Ownership (UO) Services (S) user_tokens token_project Groups (G) Group Ownership (GO) User Group (UG) Group Assignment (GA) token_roles PERMS

Sandhu, Ravi

96

Production of Meson Pairs Involving $L \  

E-Print Network (OSTI)

We present a formalism for studying the exclusive production or decay of mesons with any value of the internal orbital angular momentum L. As an application, we discuss the production of meson pairs (involving tensor and pseudotensor mesons) in photon-photon collisions.

Houra-Yaou, L; Parisi, J; Murgia, F; Hansson, J

1997-01-01T23:59:59.000Z

97

Significance tests for paired-comparison experiments  

Science Journals Connector (OSTI)

......FLECKENSTEIN, M., FREUND, R. A. & JACKSON, J. B. (1958). A paired comparison test of type- writer carbon papers. Tappi, 41, 128-30. HARTLEY, H. O. (1950). The use of range in analysis of variance. Biometrika, 37, 271-80. HARVARD......

T. H. STARKS; H. A. DAVID

1961-06-01T23:59:59.000Z

98

Ionization Chambers in the FLASH Dump Line  

E-Print Network (OSTI)

. 7, 2010FLASH Seminar, Dec. 7, 2010 BPM 13DUMP Dump Line Upgrade 2009Dump Line Upgrade 2009 BPM 9DUMP BPM 5DUMP Toroid 9DUMP OTR screen 9DUMP BLM 14DUMP BLM 13.1DUMP 13.2DUMP BLM 9DUMP BLM 6DUMP BLM 1.1DUMP 1.2DUMP BPM 10DUMP BPM 16DUMP 8 x BHM 16DUMP BLM 14R.DUMP 14L.DUMP 14U.DUMP 14D.DUMP Ionization

99

Resonance ionization detection of combustion radicals  

SciTech Connect

Fundamental research on the combustion of halogenated organic compounds with emphasis on reaction pathways leading to the formation of chlorinated aromatic compounds and the development of continuous emission monitoring methods will assist in DOE efforts in the management and disposal of hazardous chemical wastes. Selective laser ionization techniques are used in this laboratory for the measurement of concentration profiles of radical intermediates in the combustion of chlorinated hydrocarbon flames. A new ultrasensitive detection technique, made possible with the advent of tunable VUV laser sources, enables the selective near-threshold photoionization of all radical intermediates in premixed hydrocarbon and chlorinated hydrocarbon flames.

Cool, T.A. [Cornell Univ., Ithaca, NY (United States)

1993-12-01T23:59:59.000Z

100

(Resonance ionization spectroscopy and its applications)  

SciTech Connect

The field of Resonance Ionization Spectroscopy grew out of work done in the Photophysics Group at Oak Ridge National Laboratory. As one of the original developers of this field the traveler has continued to attend this meeting on a regular basis. The traveler was originally asked to present an invited talk and to present part of a short course offered to graduate students attending the conference. Subsequently, the traveler was also asked to chair a session and to be a judge of the students papers entered in a contest for a $1000 first prize.

Payne, M.G.

1990-10-05T23:59:59.000Z

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


101

Dielectric liquid ionization chambers for detecting fast neutrons  

E-Print Network (OSTI)

Three ionization chambers with different geometries have been constructed and filled with dielectric liquids for detection of fast neutrons. The three dielectric liquids studied were Tetramethylsilane (TMS), Tetramethylpentane ...

Boyd, Erin M

2008-01-01T23:59:59.000Z

102

IONIZATION OF EXTRASOLAR GIANT PLANET ATMOSPHERES  

SciTech Connect

Many extrasolar planets orbit close in and are subject to intense ionizing radiation from their host stars. Therefore, we expect them to have strong, and extended, ionospheres. Ionospheres are important because they modulate escape in the upper atmosphere and can modify circulation, as well as leave their signatures, in the lower atmosphere. In this paper, we evaluate the vertical location Z{sub I} and extent D{sub I} of the EUV ionization peak layer. We find that Z{sub I{approx}}1-10 nbar-for a wide range of orbital distances (a = 0.047-1 AU) from the host star-and D{sub I}/H{sub p{approx}}>15, where H{sub p} is the pressure scale height. At Z{sub I}, the plasma frequency is {approx}80-450 MHz, depending on a. We also study global ion transport, and its dependence on a, using a three-dimensional thermosphere-ionosphere model. On tidally synchronized planets with weak intrinsic magnetic fields, our model shows only a small, but discernible, difference in electron density from the dayside to the nightside ({approx}9 x 10{sup 13} m{sup -3} to {approx}2 x 10{sup 12} m{sup -3}, respectively) at Z{sub I}. On asynchronous planets, the distribution is essentially uniform. These results have consequences for hydrodynamic modeling of the atmospheres of close-in extrasolar giant planets.

Koskinen, Tommi T. [Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ (United States); Cho, James Y-K. [Astronomy Unit, School of Mathematical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom); Achilleos, Nicholas; Aylward, Alan D., E-mail: tommi@lpl.arizona.ed [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

2010-10-10T23:59:59.000Z

103

Neutron drops and neutron pairing energy  

Science Journals Connector (OSTI)

The ground state energy of a six-neutron drop is computed with variational and Green’s function Monte Carlo methods using the Argonne v18 two-nucleon and the Urbana three-nucleon potentials. Combined with earlier results from investigations of the drops 8n and 7n, this energy gives a 1p-shell pairing energy of (1.8±0.4) MeV. The generalized Skyrme effective interaction discussed in the earlier work is applied to these nuclei by calculating, for the open-shell drops 7n and 6n, the matrix elements of the Skyrme t matrix directly for the states involved. The pairing energy obtained is 1.50 MeV, in reasonable agreement with the accurate calculations.

A. Smerzi; D. G. Ravenhall; V. R. Pandharipande

1997-11-01T23:59:59.000Z

104

A search for resonant Z pair production  

SciTech Connect

I describe a search for anomalous production of Z pairs through a new massive resonance X in 2.5-2.9 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV using the CDFII Detector at the Fermilab Tevatron. I reconstruct Z pairs through their decays to electrons, muons, and quarks. To achieve perhaps the most efficient lepton reconstruction ever used at CDF, I apply a thorough understanding of the detector and new reconstruction software heavily revised for this purpose. In particular, I have designed and employ new general-purpose algorithms for tracking at large {eta} in order to increase muon acceptance. Upon analyzing the unblinded signal samples, I observe no X {yields} ZZ candidates and set upper limits on the production cross section using a Kaluza-Klein graviton-like acceptance.

Boveia, Antonio; /UC, Santa Barbara

2008-12-01T23:59:59.000Z

105

Infrared Properties of Close Pairs of Galaxies  

E-Print Network (OSTI)

We discuss spectroscopy and infrared photometry for a complete sample of ~ 800 galaxies in close pairs objectively selected from the CfA2 redshift survey. We use 2MASS to compare near infrared color-color diagrams for our sample with the Nearby Field Galaxy Sample and with a set of IRAS flux-limited pairs from Surace et al. We construct a basic statistical model to explore the physical sources of the substantial differences among these samples. The model explains the spread of near infrared colors and is consistent with a picture where central star formation is triggered by the galaxy-galaxy interaction before a merger occurs. For 160 galaxies we report new, deep JHK photometry within our spectroscopic aperture and we use the combined spectroscopic and photometric data to explore the physical conditions in the central bursts. We find a set of objects with H-K >= 0.45 and with a large F(FIR)/F(H). We interpret the very red H-K colors as evidence for 600-1000 K dust within compact star-forming regions, perhaps similar to super-star clusters identified in individual well-studied interacting galaxies. The galaxies in our sample are candidate ``hidden'' bursts or, possibly, ``hidden'' AGN. Over the entire pair sample, both spectroscopic and photometric data show that the specific star formation rate decreases with the projected separation of the pair. The data suggest that the near infrared color-color diagram is also a function of the projected separation; all of the objects with central near infrared colors indicative of bursts of star formation lie at small projected separation.

Margaret J. Geller; Scott J. Kenyon; Elizabeth J. Barton; Thomas H. Jarrett; Lisa J. Kewley

2006-08-02T23:59:59.000Z

106

Locating and paired-dominating sets in graphs  

Science Journals Connector (OSTI)

In this paper, we continue the study of paired-domination in graphs introduced by Haynes and Slater [T.W. Haynes, P.J. Slater, Paired-domination in graphs, Networks 32 (1998), 199–206]. A paired-dominating set of a graph G with no isolated vertex is a dominating set S of vertices whose induced subgraph has a perfect matching. We consider paired-dominating sets which are also locating sets, that is distinct vertices of G are dominated by distinct subsets of the paired-dominating set. We consider three variations of sets which are paired-dominating and locating sets and investigate their properties.

John McCoy; Michael A. Henning

2009-01-01T23:59:59.000Z

107

Pressurized H_{2} rf Cavities in Ionizing Beams and Magnetic Fields  

SciTech Connect

A major technological challenge in building a muon cooling channel is operating RF cavities in multi-tesla external magnetic fields. We report the first experimental characterization of a high pressure gas-filled 805 MHz RF cavity for use with intense ionizing beams and strong external magnetic fields. RF power consumption by beam-induced plasma was investigated with hydrogen and deuterium gases with pressures between 20 and 100 atm and peak RF gradients between 5 and 50 MV/m. The energy absorption per ion pair-RF cycle ranges from 10?18 to 10?16 J. The low pressure case agrees well with an analytical model based on electron and ion mobilities. Varying concentrations of oxygen gas were investigated to remove free electrons from the cavity and reduce the RF power consumption. Measurements of the electron attachment time to oxygen and rate of ion-ion recombination were also made. Additionally, we demonstrate the operation of the gas-filled RF cavity in a solenoidal field of up to 3 T, finding no major magnetic field dependence. These results indicate that a high pressure gas-filled cavity is potentially a viable technology for muon ionization cooling.

Chung, M.; et al.

2013-10-01T23:59:59.000Z

108

1. Introduction Alanine-based ionizing radiation dosimetry is firmly  

E-Print Network (OSTI)

1. Introduction Alanine-based ionizing radiation dosimetry is firmly woven into the fabric of high-dose System and Its Implications in High-Dose Ionizing Radiation Metrology Volume 113 Number 2 March.g., radiochromic dosimetry). From the NMI's perspective, the broad absorbed- dose range of the alanine system

109

Electron Capture in a Fully Ionized Plasma  

E-Print Network (OSTI)

Properties of fully ionized water plasmas are discussed including plasma charge density oscillations and the screening of the Coulomb law especially in the dilute classical Debye regime. A kinetic model with two charged particle scattering events determines the transition rate per unit time for electron capture by a nucleus with the resulting nuclear transmutations. Two corrections to the recent Maiani et al. calculations are made: (i) The Debye screening length is only employed within its proper domain of validity. (ii) The WKB approximation employed by Maiani in the long De Broglie wave length limit is evidently invalid. We replace this incorrect approximation with mathematically rigorous Calogero inequalities in order to discuss the scattering wave functions. Having made these corrections, we find a verification for our previous results based on condensed matter electro-weak quantum field theory for nuclear transmutations in chemical batteries.

A. Widom; J. Swain; Y. N. Srivastava

2014-09-17T23:59:59.000Z

110

Photo-Ionization of the Hydrogen Molecule  

Science Journals Connector (OSTI)

One-center wave functions are employed to investigate the photo-ionization of the hydrogen molecule from its ground state X(1s??g1+), from 700 to 300 Å. It is assumed that the residual ion is left in its ground state, and the free electron is in a p? or p? orbital. Using the one-center wave functions for H2+ for the internuclear distance equal to 1. 4a0, the free-electron wave functions are obtained by solving the integrodifferential equations in exchange and polarized-orbital approximations. The oscillator strengths obtained in the polarized-orbital approximation are found to be in satisfactory agreement with the experimental data.

S. P. Khare

1968-09-05T23:59:59.000Z

111

Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation  

NLE Websites -- All DOE Office Websites (Extended Search)

Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation Print Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation Print Understanding charge-transfer processes at the atomic level of nanoscale systems is of the utmost importance for designing nanodevices based on quantum-dot structures, nanotubes, or two-dimensional graphene sheets. Researchers from Western Michigan University, Berkeley Lab, and other international research facilities investigated charge-transfer processes and subsequent ion fragmentation dynamics in nanoclusters composed of argon (Ar) shells and xenon (Xe) cores. The clusters were site-selectively ionized (i.e, ionization took place either in the xenon core or in the argon shell). Using a high-resolution photoelectron-ion coincidence technique at ALS Beamlines 10.0.1 and 11.0.2, the researchers concluded that charge-transfer processes and fragmentation dynamics are strongly influenced by the environment of the initially ionized atoms.

112

Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation  

NLE Websites -- All DOE Office Websites (Extended Search)

Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation Print Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation Print Understanding charge-transfer processes at the atomic level of nanoscale systems is of the utmost importance for designing nanodevices based on quantum-dot structures, nanotubes, or two-dimensional graphene sheets. Researchers from Western Michigan University, Berkeley Lab, and other international research facilities investigated charge-transfer processes and subsequent ion fragmentation dynamics in nanoclusters composed of argon (Ar) shells and xenon (Xe) cores. The clusters were site-selectively ionized (i.e, ionization took place either in the xenon core or in the argon shell). Using a high-resolution photoelectron-ion coincidence technique at ALS Beamlines 10.0.1 and 11.0.2, the researchers concluded that charge-transfer processes and fragmentation dynamics are strongly influenced by the environment of the initially ionized atoms.

113

Laser plasma formation assisted by ultraviolet pre-ionization  

SciTech Connect

We present experimental and modeling studies of air pre-ionization using ultraviolet (UV) laser pulses and its effect on laser breakdown of an overlapped near-infrared (NIR) pulse. Experimental studies are conducted with a 266?nm beam (fourth harmonic of Nd:YAG) for UV pre-ionization and an overlapped 1064?nm NIR beam (fundamental of Nd:YAG), both having pulse duration of ?10?ns. Results show that the UV beam produces a pre-ionized volume which assists in breakdown of the NIR beam, leading to reduction in NIR breakdown threshold by factor of >2. Numerical modeling is performed to examine the ionization and breakdown of both beams. The modeled breakdown threshold of the NIR, including assist by pre-ionization, is in reasonable agreement with the experimental results.

Yalin, Azer P., E-mail: ayalin@engr.colostate.edu; Dumitrache, Ciprian [Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States); Wilvert, Nick [Sandia Laboratory, Albuquerque, New Mexico 87123 (United States); Joshi, Sachin [Cummins Inc., Columbus, Indiana 47201 (United States); Shneider, Mikhail N. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States)

2014-10-15T23:59:59.000Z

114

A comprehensive range of X-ray ionized reflection models  

E-Print Network (OSTI)

X-ray ionized reflection occurs when a surface is irradiated with X-rays so intense that its ionization state is determined by the ionization parameter xi propto F/n, where F is the incident flux and n the gas density. It occurs in accretion, onto compact objects including black holes in both active galaxies and stellar-mass binaries, and possibly in gamma-ray bursts. Computation of model reflection spectra is often time-consuming. Here we present the results from a comprehensive grid of models computed with our code, which has now been extended to include what we consider to be all energetically-important ionization states and transitions. This grid is being made available as an ionized-reflection model, REFLION, for XSPEC.

R. R. Ross; A. C. Fabian

2005-01-07T23:59:59.000Z

115

Near-threshold positron impact ionization of hydrogen  

SciTech Connect

The hyperspherical hidden crossing method (HHCM) is used to investigate positron impact ionization of hydrogen near threshold. An important feature of this method is that it can provide valuable insight into scattering processes. In the calculation of positron-hydrogen ionization, the adiabatic Hamiltonian is expanded about the Wannier saddle point; anharmonic corrections are treated perturbatively. The S-wave results are consistent with the Wannier threshold law and with the extended threshold law that was previously derived using the HHCM. We have extended the previous HHCM calculation to higher angular momenta L and have calculated the absolute ionization cross-section for L = 0, 1 and 2. The HHCM calculation confirms that the S-wave ionization cross-section is small and provides the reason why it is small. The HHCM ionization cross-section (summed over the lowest partial waves) is compared with a convergent close-coupling calculation, a 33-state close-coupling calculation and experimental data.

Macek, Joseph H [ORNL; Ward, S.J. [University of North Texas; Jansen, Krista [University of North Texas; Shertzer, J. [College Holy Cross, Worcester, MA

2008-01-01T23:59:59.000Z

116

Escherichia coli Genes and Pathways Involved in Surviving Extreme Exposure to Ionizing Radiation  

Science Journals Connector (OSTI)

...doses of ionizing radiation does not depend on...the effects of high doses of ionizing radiation (IR). The repair...IR resistance. A range of modern screening...survive increasing doses of ionizing radiation in comparison to...

Rose T. Byrne; Stefanie H. Chen; Elizabeth A. Wood; Eric L. Cabot; Michael M. Cox

2014-07-21T23:59:59.000Z

117

Backward Raman amplification in a partially ionized gas A. A. Balakin,1  

E-Print Network (OSTI)

was accessed 10,11 . The experimental success was achieved using a gas jet of propane, subse- quently ionized of propane opens up the question of coupling in a partially ionized gas. Any additional ionization during

118

Near-coincident K-line and K-edge energies as ionization diagnostics for some high atomic number plasmas  

SciTech Connect

For some high atomic number atoms, the energy of the K-edge is tens of eVs higher than the K-line energy of another atom, so that a few eV increase in the line's energy results in a decreasing transmission of the x-ray through a filter of the matching material. The transmission of cold iridium's Asymptotically-Equal-To 63.287 keV K{alpha}{sub 2} line through a lutetium filter is 7% lower when emitted by ionized iridium, consistent with an energy increase of {Delta}{epsilon} Asymptotically-Equal-To 10{+-}1 eV associated with the ionization. Likewise, the transmission of the K{beta}{sub 1} line of ytterbium through a near-coincident K-edge filter changes depending on plasma parameters that should affect the ionization. Systematic exploration of filter-line pairs like these could become a unique tool for diagnostics of suitable high energy density plasmas.

Pereira, N. R. [Ecopulse, Inc., P.O. Box 528, Springfield, Virginia 22150 (United States); Weber, B. V.; Phipps, D. G.; Schumer, J. W. [Naval Research Laboratory, Washington, DC 20375 (United States); Seely, J. F. [Artep, Inc., 2922 Excelsior Springs Court, Ellicott City, Maryland 21042 (United States); Carroll, J. J. [Army Research Laboratory, Adelphi, Maryland 20873 (United States); Vanhoy, J. R. [United States Naval Academy, Annapolis, Maryland 21402 (United States); Slabkowska, K.; Polasik, M. [Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 7, 87-100 Torun (Poland)

2012-10-15T23:59:59.000Z

119

Jordan Pairs and Hopf Algebras John R. Faulkner  

E-Print Network (OSTI)

Jordan Pairs and Hopf Algebras John R. Faulkner A (quadratic) Jordan pair is constructed from a Z-graded Hopf algebra having divided power sequences over. The notion of a divided power representation of a Jordan pair is introduced and the universal

120

POLYNOMIAL IDENTITIES AND NON-IDENTITIES OF SPLIT JORDAN PAIRS  

E-Print Network (OSTI)

POLYNOMIAL IDENTITIES AND NON-IDENTITIES OF SPLIT JORDAN PAIRS Erhard Neher Abstract. We show that split Jordan pairs over rings without 2-torsion can be distinguished by polynomial identities with integer coefficients. In particular, this holds for simple finite-dimensional Jordan pairs over

Neher, Erhard

Note: This page contains sample records for the topic "ionization brems pair" 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

LM194LM394SupermatchPair December 1994  

E-Print Network (OSTI)

TL H 9241 LM194LM394SupermatchPair December 1994 LM194 LM394 Supermatch Pair General Description The LM194 and LM394 are junction isolated ultra well- matched monolithic NPN transistor pairs emitter to ensure com- plete isolation between devices The LM194 and LM394 will provide a considerable

Lanterman, Aaron

122

Weierstrass Pairs and Minimum Distance of Goppa Codes  

Science Journals Connector (OSTI)

We prove that elements of the Weierstrass gap set of a pair of points may be used to define a geometric Goppa code which has minimum distance greater than the usual lower bound. We determine the Weierstrass gap set of a pair of any two Weierstrass ... Keywords: Hermitian code, Weierstrass pair, Weierstrass point

Gretchen L. Matthews

2001-03-01T23:59:59.000Z

123

E-Print Network 3.0 - assisted laser ionization Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Summary: of a high power pulsed far-infrared laser. Furthermore, impurity ionization with terahertz radiation can... of ionization capture processes due to the Poole-Frenkel...

124

E-Print Network 3.0 - activities involving ionizing Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Collection: Physics 62 Magnetic field effect on tunnel ionization of deep impurities by terahertz radiation S.D. Ganichev1 Summary: Magnetic field effect on tunnel ionization of...

125

Nuclear Pairing from Two-body Microscopic Forces: Analysis of the Cooper Pair Wavefunctions  

E-Print Network (OSTI)

In a recent paper we studied the behavior of the pairing gaps $\\Delta_F$ as a function of the Fermi momentum $k_F$ for neutron and nuclear matter in all relevant angular momentum channels where superfluidity is believed to naturally emerge. The calculations employed realistic chiral nucleon-nucleon potentials with the inclusion of three-body forces and self-energy effects. In this contribution, after a detailed description of the numerical method we employed in the solution of the BCS equations, we will show a preliminary analysis of the Cooper pair wavefunctions.

Finelli, P; Holt, J W

2014-01-01T23:59:59.000Z

126

Plasmadynamics and ionization kinetics of thermionic energy conversion  

SciTech Connect

To reduce the plasma arc-drop, thermionic energy conversion is studied with both analytical and numerical tools. Simplifications are made in both the plasmadynamic and ionization-recombination theories. These are applied to a scheme proposed presently using laser irradiation to enhance the ionization kinetics of the thermionic plasma and thereby reduce the arc-drop. It is also predicted that it is possible to generate the required laser light from a thermionic-type cesium plasma. The analysis takes advantage of theoretical simplifications derived for the ionization-recombination kinetics. It is shown that large laser ionization enhancements can occur and that collisional cesium recombination lasing is expected. To complement the kinetic theory, a numerical method is developed to solve the thermionic plasma dynamics. To combine the analysis of ionization-recombination kinetics with the plasma dynamics of thermionic conversion, a finite difference computer program is constructed. It is capable of solving for both unsteady and steady thermionic converter behavior including possible laser ionization enhancement or atomic recombination lasing. A proposal to improve thermionic converter performance using laser radiation is considered. In this proposed scheme, laser radiation impinging on a thermionic plasma enhances the ionization process thereby raising the plasma density and reducing the plasma arc-drop. A source for such radiation may possibly be a cesium recombination laser operating in a different thermionic converter. The possibility of this being an energy efficient process is discussed. (WHK)

Lawless, J.L. Jr.; Lam, S.H.

1982-02-01T23:59:59.000Z

127

Lattice Boltzmann method for weakly ionized isothermal plasmas  

Science Journals Connector (OSTI)

In this paper, a lattice Boltzmann method (LBM) for weakly ionized isothermal plasmas is presented by introducing a rescaling scheme for the Boltzmann transport equation. Without using this rescaling, we found that the nondimensional relaxation time used in the LBM is too large and the LBM does not produce physically realistic results. The developed model was applied to the electrostatic wave problem and the diffusion process of singly ionized helium plasmas with a 1–3% degree of ionization under an electric field. The obtained results agree well with theoretical values.

Huayu Li and Hyungson Ki

2007-12-21T23:59:59.000Z

128

Lattice Boltzmann method for weakly ionized isothermal plasmas  

SciTech Connect

In this paper, a lattice Boltzmann method (LBM) for weakly ionized isothermal plasmas is presented by introducing a rescaling scheme for the Boltzmann transport equation. Without using this rescaling, we found that the nondimensional relaxation time used in the LBM is too large and the LBM does not produce physically realistic results. The developed model was applied to the electrostatic wave problem and the diffusion process of singly ionized helium plasmas with a 1-3% degree of ionization under an electric field. The obtained results agree well with theoretical values.

Li Huayu; Ki, Hyungson [Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan 48824-1226 (United States)

2007-12-15T23:59:59.000Z

129

Photo-double-ionization of the nitrogen molecule  

Science Journals Connector (OSTI)

The triple differential cross sections of the photo-double-ionization of the nitrogen molecule to the X 1?+g and a3?u N22+ states have been measured at about 20 eV above their respective ionization thresholds in the equal energy sharing kinematics and calculated using a model which makes use of correlated two-center double continuum wave functions. The comparison of the results with those obtained by the Gaussian parametrization method applied in the past with success to heliumlike targets shows the influence of the molecular nature of the N2 target in the photo-double-ionization.

P. Bolognesi; B. Joulakian; A. A. Bulychev; O. Chuluunbaatar; L. Avaldi

2014-05-07T23:59:59.000Z

130

The Density Effect for the Ionization Loss in Various Materials  

Science Journals Connector (OSTI)

The density effect for the ionization loss of charged particles has been calculated for a number of metals, scintillating materials, gases at various pressures, and photographic emulsion, using a dispersion model involving an appropriate number of dispersion oscillators for each substance. The results are presented in the form of graphs which can be used to correct the ionization loss for the density effect. The theoretical curves for silver chloride and anthracene are in reasonable agreement with experiments on the ionization loss of ?-mesons. A general derivation of the equations for the density effect is given.

R. M. Sternheimer

1952-11-15T23:59:59.000Z

131

Ionization and scintillation of nuclear recoils in gaseous xenon  

E-Print Network (OSTI)

Ionization and scintillation produced by nuclear recoils in gaseous xenon at approximately 14 bar have been simultaneously observed in an electroluminescent time projection chamber. Neutrons from radioisotope $\\alpha$-Be neutron sources were used to induce xenon nuclear recoils, and the observed recoil spectra were compared to a detailed Monte Carlo employing estimated ionization and scintillation yields for nuclear recoils. The ability to discriminate between electronic and nuclear recoils using the ratio of ionization to primary scintillation is demonstrated. These results encourage further investigation on the use of xenon in the gas phase as a detector medium in dark matter direct detection experiments.

J. Renner; V. M. Gehman; A. Goldschmidt; H. S. Matis; T. Miller; Y. Nakajima; D. Nygren; C. A. B. Oliveira; D. Shuman; V. Álvarez; F. I. G. Borges; S. Cárcel; J. Castel; S. Cebrián; A. Cervera; C. A. N. Conde; T. Dafni; T. H. V. T. Dias; J. Díaz; R. Esteve; P. Evtoukhovitch; L. M. P. Fernandes; P. Ferrario; A. L. Ferreira; E. D. C. Freitas; A. Gil; H. Gómez; J. J. Gómez-Cadenas; D. González-Díaz; R. M. Gutiérrez; J. Hauptman; J. A. Hernando Morata; D. C. Herrera; F. J. Iguaz; I. G. Irastorza; M. A. Jinete; L. Labarga; A. Laing; I. Liubarsky; J. A. M. Lopes; D. Lorca; M. Losada; G. Luzón; A. Marí; J. Martín-Albo; A. Martínez; A. Moiseenko; F. Monrabal; M. Monserrate; C. M. B. Monteiro; F. J. Mora; L. M. Moutinho; J. Muñoz Vidal; H. Natal da Luz; G. Navarro; M. Nebot-Guinot; R. Palma; J. Pérez; J. L. Pérez Aparicio; L. Ripoll; A. Rodríguez; J. Rodríguez; F. P. Santos; J. M. F. dos Santos; L. Seguí; L. Serra; A. Simón; C. Sofka; M. Sorel; J. F. Toledo; A. Tomás; J. Torrent; Z. Tsamalaidze; J. F. C. A. Veloso; J. A. Villar; R. C. Webb; J. White; N. Yahlali

2014-09-09T23:59:59.000Z

132

Ionizing radiation effects on silicon test structures  

SciTech Connect

The effects of {sup 60}Co gamma irradiation on MOSCAPS and special junction diode detectors have been studied. The capacitors were used to ellicit the charge accumulation and anneal in two types of thermally grown oxides representative of those used in routine detector processing. Ion implanted, oxide passivated junction detectors having 0.25 and 1 cm{sup 2} areas and perimeter to area ratios of 1 (a square), 2 and 5 were designed and constructed to amplify the ionizing effects expected to largely affect junction edges through changes in fixed oxide charges. Detectors were exposed to over 4 Mrad and showed clear increases in leakage current in proportion to the junction edge length. Annealing schedules were determined to provide a continuous response to incremental irradiations and subsequent room temperature anneals of leakage current. Besides an increase in gate threshold, little effect on the C(V) response was found. PISCES simulation of the edge fields using different fixed oxide charge revealed regions of very high lateral fields near the junction edges for fixed charges in the 2 {times} 10{sup 12}/cm{sup 2} range expected from the capacitor studies which could be responsible for the observed leakage currents.

Kraner, H.W.; Beuttenmuller, R.; Chen, W.; Kierstead, J.A.; Li, Z.; Zhang, Y. [Brookhaven National Lab., Upton, NY (United States); Dou, L. [Wayne State Univ., Detroit, MI (United States); Fretwurst, E.; Lindstroem, G. [Univ. of Hamburg (Germany)

1993-12-01T23:59:59.000Z

133

Systems and methods for cylindrical hall thrusters with independently controllable ionization and acceleration stages  

DOE Patents (OSTI)

Systems and methods may be provided for cylindrical Hall thrusters with independently controllable ionization and acceleration stages. The systems and methods may include a cylindrical channel having a center axial direction, a gas inlet for directing ionizable gas to an ionization section of the cylindrical channel, an ionization device that ionizes at least a portion of the ionizable gas within the ionization section to generate ionized gas, and an acceleration device distinct from the ionization device. The acceleration device may provide an axial electric field for an acceleration section of the cylindrical channel to accelerate the ionized gas through the acceleration section, where the axial electric field has an axial direction in relation to the center axial direction. The ionization section and the acceleration section of the cylindrical channel may be substantially non-overlapping.

Diamant, Kevin David; Raitses, Yevgeny; Fisch, Nathaniel Joseph

2014-05-13T23:59:59.000Z

134

Ionization and transmission efficiency in an electrospray ionization-mass spectrometry interface  

SciTech Connect

The efficiency of sample ionization by electrospray ionization (ESI) and the transmission of the charged droplets and gas-phase ions through an ESI interface were investigated in order to advance the understanding of how these factors affect mass spectrometry (MS) sensitivity. In addition, the effects of the ES emitter distance to the inlet, solution flow rate, and inlet temperature to the ionization and transmission efficiency were characterized. Quantitative measurements of ES current loss throughout the ESI interface were accomplished by electrically isolating the front surface of the interface from the inner wall of the heated inlet capillary, enabling losses on the two surfaces to be distinguished. The ES current lost to the front surface of the ESI interface was also spatially profiled with a linear array of 340-µm-dia. electrodes placed adjacent to the inlet capillary entrance. Current transmitted as gas-phase ions was differentiated from charged droplets and solvent clusters by directly measuring sensitivity with a single quadrupole mass spectrometer. The study has revealed a large sampling efficiency into the inlet capillary (>90% at an emitter distance of 1 mm), a global rather than a local gas dynamic effect on the shape of the ES plume due to the gas flow conductance limit of the inlet capillary, a large (>80%) loss of analyte after transmission through the inlet due to incomplete desolvation at a solution flow rate of 1.0 µL/min, and a decrease in analyte peak intensity at lower temperatures, despite a large increase in ES current transmission efficiency. These studies provide a clearer understanding of the parameters affecting ion transmission into the mass spectrometer, and will serve to guide the design of more efficient instrument interfaces.

Page, Jason S.; Kelly, Ryan T.; Tang, Keqi; Smith, Richard D.

2007-09-01T23:59:59.000Z

135

Characterization of nonpolar lipids and steroids by using laser-induced acoustic desorption/chemical ionization, atmospheric pressure chemical ionization, and electrospray ionization mass spectrometry  

SciTech Connect

Laser-induced acoustic desorption (LIAD) combined with ClMn(H{sub 2}O){sup +} chemical ionization (CI) was tested for the analysis of nonpolar lipids and selected steroids in a Fourier-transform ion cyclotron resonance mass spectrometer (FT-ICR). The nonpolar lipids studied, cholesterol, 5?-cholestane, cholesta-3,5-diene, squalene, and ?-carotene, were found to solely form the desired water replacement product (adduct-H{sub 2}O) upon reaction with the ClMn(H{sub 2}O){sup +} ions. The steroids, androsterone, dehydroepiandrosterone (DHEA), estrone, estradiol, and estriol, also form abundant adduct-H{sub 2}O ions, but less abundant adduct-2H{sub 2}O ions were also observed. Neither (+)APCI nor (+)ESI can ionize the saturated hydrocarbon lipid, cholestane. APCI successfully ionizes the unsaturated hydrocarbon lipids to form exclusively the intact protonated analytes. However, it causes extensive fragmentation for cholesterol and the steroids. The worst case is cholesterol that does not produce any stable protonated molecules. On the other hand, ESI cannot ionize any of the hydrocarbon analytes, saturated or unsaturated. However, ESI can be used to protonate the oxygen-containing analytes with substantially less fragmentation than for APCI in all cases except for cholesterol and estrone. In conclusion, LIAD/ClMn(H{sub 2}O){sup +} chemical ionization is superior over APCI and ESI for the mass spectrometric characterization of underivatized nonpolar lipids and steroids.

Jin, Z.; Daiya, S.; Kenttämaa, Hilkka I.

2011-01-01T23:59:59.000Z

136

Proton-neutron pairing vibrations in N=Z nuclei: Precursory soft mode of isoscalar pairing condensation  

E-Print Network (OSTI)

L=0 proton-neutron ($pn$) pair-addition and pair-removal strengths in $^{40}$Ca and $^{56}$Ni are investigated by means of the $pn$ particle-particle random-phase approximation employing a Skyrme energy-density functional. It is found that the collectivity of the lowest $J^\\pi = 1^+$ state in the adjacent odd-odd nuclei becomes stronger as the strength of the isoscalar (T=0) pairing interaction increases. The results suggest the emergence of the T=0 $pn$-pairing vibrational mode as a possible critical phenomenon toward the T=0 pairing condensation.

Kenichi Yoshida

2014-09-17T23:59:59.000Z

137

Proton-neutron pairing vibrations in N=Z nuclei: Precursory soft mode of isoscalar pairing condensation  

E-Print Network (OSTI)

L=0 proton-neutron ($pn$) pair-addition and pair-removal strengths in $^{40}$Ca and $^{56}$Ni are investigated by means of the $pn$ particle-particle random-phase approximation employing a Skyrme energy-density functional. It is found that the collectivity of the lowest $J^\\pi = 1^+$ state in the adjacent odd-odd nuclei becomes stronger as the strength of the isoscalar (T=0) pairing interaction increases. The results suggest the emergence of the T=0 $pn$-pairing vibrational mode as a possible critical phenomenon toward the T=0 pairing condensation.

Yoshida, Kenichi

2014-01-01T23:59:59.000Z

138

Rules and Regulations for Control of Ionizing Radiation (Arkansas) |  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Rules and Regulations for Control of Ionizing Radiation (Arkansas) Rules and Regulations for Control of Ionizing Radiation (Arkansas) Rules and Regulations for Control of Ionizing Radiation (Arkansas) < Back Eligibility Utility Program Info State Arkansas Program Type Environmental Regulations Siting and Permitting Provider Department of Health The Rules and Regulations for Control of Ionizing Radiation are the Arkansas state laws made in accordance the federal Nuclear Regulatory Commission Rules. Any contractor with the US DOE or US Nuclear Regulatory Commission is exempt from the state laws. This set of rules and regulations basically restates the federal policy to ensure that Arkansas is in compliance with the federal standards governing nuclear energy. Specifically the State rules are equivalent to Nuclear Regulatory

139

The Degradation of Solid Polymethylmethacrylate by Ionizing Radiation  

Science Journals Connector (OSTI)

...Polymethylmethacrylate by Ionizing Radiation P. Alexander A. Charlesby...inversely proportional to the radiation dose (plus a small quantity of...of measuring high-energy radiation doses in the range of about 1 million rontgens...

1954-01-01T23:59:59.000Z

140

Ionizing Radiation Induces Delayed Hyperrecombination in Mammalian Cells  

Science Journals Connector (OSTI)

...instability is critical to radiation risk assessment and for determining...the many delayed effects of radiation, chromosomal instability is...detrimental effects over a range of doses of ionizing radiation. Furthermore, a rapid and...

Lei Huang; Suzanne Grim; Leslie E. Smith; Perry M. Kim; Jac A. Nickoloff; Olga G. Goloubeva; William F. Morgan

2004-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

22.01 Introduction to Ionizing Radiation, Fall 2003  

E-Print Network (OSTI)

Introduction to basic properties of ionizing radiations and their uses in medicine, industry, science, and environmental studies. Discusses natural and man-made radiation sources, energy deposition and dose calculations, ...

Coderre, Jeffrey A.

142

Laser Multiphoton Ionization of Tetrakis(dimethylamino)ethylene  

Science Journals Connector (OSTI)

(4) Also, TDAE has found a place in current plasma research as it can produce plasmas at densities approaching 1013 charges per cm3 via ionization with 193 nm light. ...

Byron H. Smith; Robert N. Compton

2014-02-22T23:59:59.000Z

143

One Monopole?Antimonopole Pair Solutions  

Science Journals Connector (OSTI)

We present new classical generalized one monopole?antimonopole pair solutions of the SU(2) Yang?Mills?Higgs theory with the Higgs field in the adjoint representation. We show that in general the one monopole?antimonopole solution need not be solved by imposing m ??winding number to be integer greater than one. We also show that this solution can be solved when m?=?1 by transforming the large distance asymptotic solutions to general solutions that depend on a parameter p. Secondly we show that these large distance asymptotic solutions can be further generalized to the Jacobi elliptic functions. We focus our numerical calculation on the Jacobi elliptic functions solution when the n ??winding number is one and show that this generalized Jacobi elliptic 1?MAP solution possesses lower energy. All these solutions are numerical finite energy non?BPS solutions of the Yang?Mills?Higgs field theory.

Rosy Teh; Khai?Ming Wong

2009-01-01T23:59:59.000Z

144

Pair-Production Supernovae: Theory and Observation  

E-Print Network (OSTI)

I review the physical properties of pair-production supernovae (PPSNe) as well as the prospects for them to be constrained observationally. In very massive (140-260 solar mass) stars, much of the pressure support comes from the radiation field, meaning that they are loosely bound, with an adiabatic coefficient that is close to the minimum stable value. Near the end of C/O burning, the central temperature increases to the point that photons begin to be converted into electron-positron pairs, softening gamma below this critical value. The result is a runaway collapse, followed by explosive burning that completely obliterates the star. While these explosions can be up to 100 times more energetic that core collapse and Type Ia supernovae, their peak luminosities are only slightly greater. However, due both to copious Ni-56 production and hydrogen recombination, they are brighter much longer, and remain observable for ~ 1 year. Since metal enrichment is a local process, PPSNe should occur in pockets of metal-free gas over a broad range of redshifts, greatly enhancing their detectability, and distributing their nucleosyntehtic products about the Milky Way. This means that measurements of the abundances of metal-free stars should be thought of as directly constraining these objects. It also means that ongoing supernova searches, already provide weak constraints for PPSN models. A survey with the NIRCam instrument on JWST, on the other hand, would be able to extend these limits to z ~ 10. Observing a 0.3 deg^2 patch of sky for one week per year for three consecutive years, such a program would either detect or rule out the existence of these remarkable objects.

Evan Scannapieco

2006-09-07T23:59:59.000Z

145

Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation  

NLE Websites -- All DOE Office Websites (Extended Search)

Site-Selective Ionization in Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation Print Wednesday, 30 June 2010 00:00 Understanding charge-transfer processes at the atomic level of nanoscale systems is of the utmost importance for designing nanodevices based on quantum-dot structures, nanotubes, or two-dimensional graphene sheets. Researchers from Western Michigan University, Berkeley Lab, and other international research facilities investigated charge-transfer processes and subsequent ion fragmentation dynamics in nanoclusters composed of argon (Ar) shells and xenon (Xe) cores. The clusters were site-selectively ionized (i.e, ionization took place either in the xenon core or in the argon shell). Using a high-resolution photoelectron-ion coincidence technique at ALS Beamlines 10.0.1 and 11.0.2, the researchers concluded that charge-transfer processes and fragmentation dynamics are strongly influenced by the environment of the initially ionized atoms.

146

ALFVEN WAVES IN A PARTIALLY IONIZED TWO-FLUID PLASMA  

SciTech Connect

Alfven waves are a particular class of magnetohydrodynamic waves relevant in many astrophysical and laboratory plasmas. In partially ionized plasmas the dynamics of Alfven waves is affected by the interaction between ionized and neutral species. Here we study Alfven waves in a partially ionized plasma from the theoretical point of view using the two-fluid description. We consider that the plasma is composed of an ion-electron fluid and a neutral fluid, which interact by means of particle collisions. To keep our investigation as general as possible, we take the neutral-ion collision frequency and the ionization degree as free parameters. First, we perform a normal mode analysis. We find the modification due to neutral-ion collisions of the wave frequencies and study the temporal and spatial attenuation of the waves. In addition, we discuss the presence of cutoff values of the wavelength that constrain the existence of oscillatory standing waves in weakly ionized plasmas. Later, we go beyond the normal mode approach and solve the initial-value problem in order to study the time-dependent evolution of the wave perturbations in the two fluids. An application to Alfven waves in the low solar atmospheric plasma is performed and the implication of partial ionization for the energy flux is discussed.

Soler, R.; Ballester, J. L.; Terradas, J. [Departament de Fisica, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Carbonell, M., E-mail: roberto.soler@uib.es, E-mail: joseluis.ballester@uib.es, E-mail: jaume.terradas@uib.es, E-mail: marc.carbonell@uib.es [Departament de Matematiques i Informatica, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain)

2013-04-20T23:59:59.000Z

147

Ionization and maximum energy of nuclei in shock acceleration theory  

E-Print Network (OSTI)

We study the acceleration of heavy nuclei at SNR shocks when the process of ionization is taken into account. Heavy atoms ($Z_N >$ few) in the interstellar medium which start the diffusive shock acceleration (DSA) are never fully ionized at the moment of injection. The ionization occurs during the acceleration process, when atoms already move relativistically. For typical environment around SNRs the photo-ionization due to the background galactic radiation dominates over Coulomb collisions. The main consequence of ionization is the reduction of the maximum energy which ions can achieve with respect to the standard result of the DSA. In fact the photo-ionization has a timescale comparable to the beginning of the Sedov-Taylor phase, hence the maximum energy is no more proportional to the nuclear charge, as predicted by standard DSA, but rather to the effective ions' charge during the acceleration process, which is smaller than the total nuclear charge $Z_N$. This result can have a direct consequence in the pred...

Morlino, Giovanni

2011-01-01T23:59:59.000Z

148

Ionization of dimethyluracil dimers leads to facile proton transfer in the absence of H-bonds  

E-Print Network (OSTI)

and electronic structure calculations. Ionization initiates3 commercially. Electronic structure calculations were

Golan, Amir

2012-01-01T23:59:59.000Z

149

The similar effects of low-dose ionizing radiation and non-ionizing radiation from background environmental levels of exposure  

Science Journals Connector (OSTI)

The meltdown and release of radioactivity (ionizing radiation) from four damaged nuclear reactors at the Fukushima Nuclear Facility in Japan in March 2011 continues to contaminate air and ocean water even 1 year ...

Cindy Sage

2012-06-01T23:59:59.000Z

150

The holographic dual of an EPR pair has a wormhole  

E-Print Network (OSTI)

We construct the holographic dual of two colored quasiparticles in maximally supersymmetric Yang-Mills theory entangled in a color singlet EPR pair. In the holographic dual the entanglement is encoded in a geometry of a non-traversable wormhole on the worldsheet of the flux tube connecting the pair. This gives a simple example supporting the recent claim by Maldacena and Susskind that EPR pairs and non-traversable wormholes are equivalent descriptions of the same physics.

Jensen, Kristan

2013-01-01T23:59:59.000Z

151

ION PAIRING AND pH: A REPLY  

Science Journals Connector (OSTI)

960. COMMENT. ( 1970) found experimentally that NaS04- ion pairs dissociate with increased pressure under conditions appropriate to the deep ocean.

1999-12-26T23:59:59.000Z

152

Pair interaction of metal atoms on a metal surface  

Science Journals Connector (OSTI)

Pair interactions of tungsten and iridium adatoms on the W {110} plane are studied by measuring two-dimensional pair distributions with two adatoms on a plane. Each distribution contains from 600 to 950 field-ion-microscopy observations. Pair energies over a distance range of ?2.5 to ?50 Å are derived by comparing the experimentally measured pair distributions with the calculated pair distributions for two noninteracting atoms. It is found that Ir-Ir pair interaction exhibits an attractive region at ?5 Å and a repulsive region around 8 Å. If an oscillatory structure exists, its amplitudes decay already to less than ?10 meV beyond 10 Å. The plane edge seems to repel Ir adatoms with a weak long-range force. The W-Ir interaction at a short range is weaker than the Ir-Ir interaction. However, the interaction extends to larger distances. From ?950 observations at 330 K with two adatoms, we derive a pair energy which exhibits two attractive and two repulsive regions, thus strongly suggesting an oscillatory structure. The pair energies derived beyond 25 Å are erratic for both Ir-Ir and W-Ir interactions, most probably because of the limited amount of data available. However, this work represents the first time statistically reliable amounts of data have been obtained for two-dimensional pair distributions with only two adatoms on a plane. The nonmonotonic behaviors of adatom-adatom interaction on the smooth W {110} plane are clearly established.

R. Casanova and T. T. Tsong

1980-12-15T23:59:59.000Z

153

Plasmadynamics and ionization kinetics of thermionic energy conversion  

SciTech Connect

To reduce the plasma arc-drop, thermionic energy conversion is studied with both analytical and numerical tools. Simplifications are made in both the plasmadynamic and ionization-recombination theories. These are applied to a scheme proposed presently using laser irradiation to enhance the ionization kinetics of the thermionic plasma and thereby reduce the arc-drop. It is also predicted that it is possible to generate the required laser light from a thermionic-type Cesium plasma. The analysis takes advantage of theoretical simplifications derived for the ionization-recombination kinetics. It is shown that large laser ionization enhancements can occur and that collisional Cesium recombination lasing is expected. To complement the kinetic theory, a numerical method is developed to solve the thermionic plasma dynamics. The effects of the complete system of electron-atom inelastic collisions on the ionization-recombination problem are shown to reduce to a system nearly as simple as the well-known one-quantum approximation. To combine the above analysis of ionization-recombination kinetics with the plasma dynamics of thermionic conversion, a finite difference computer program is constructed. Using the above developments, a proposal to improve thermionic converter performance using laser radiation is considered. In this proposed scheme, laser radiation impinging on a thermionic plasma enhances the ionization process thereby raising the plasma density and reducing the plasma arc-drop. A source for such radiation may possibly be a Cesium recombination laser operating in a different thermionic converter. The possibility of this being an energy efficient process is discussed.

Lawless, J.L. Jr.

1981-01-01T23:59:59.000Z

154

Nucleic Acid Standards | Base Pair Geometry  

NLE Websites -- All DOE Office Websites (Extended Search)

A Standard Reference Frame for the Description A Standard Reference Frame for the Description of Nucleic Acid Base-pair Geometry Table 1. Cartesian coordinates of non-hydrogen atoms in the standard reference frames of the five common nitrogenous bases Atom Base x(Ã…) y(Ã…) z(Ã…) Adenine ATOM 1 C1' A A 1 -2.479 5.346 0.000 ATOM 2 N9 A A 1 -1.291 4.498 0.000 ATOM 3 C8 A A 1 0.024 4.897 0.000 ATOM 4 N7 A A 1 0.877 3.902 0.000 ATOM 5 C5 A A 1 0.071 2.771 0.000 ATOM 6 C6 A A 1 0.369 1.398 0.000 ATOM 7 N6 A A 1 1.611 0.909 0.000 ATOM 8 N1 A A 1 -0.668 0.532 0.000 ATOM 9 C2 A A 1 -1.912 1.023 0.000 ATOM 10 N3 A A 1 -2.320 2.290 0.000

155

Unifying Projected Entangled Pair States contractions  

E-Print Network (OSTI)

The approximate contraction of a Projected Entangled Pair States (PEPS) tensor network is a fundamental ingredient of any PEPS algorithm, required for the optimization of the tensors in ground state search or time evolution, as well as for the evaluation of expectation values. An exact contraction is in general impossible, and the choice of the approximating procedure determines the efficiency and accuracy of the algorithm. We analyze different previous proposals for this approximation, and show that they can be understood via the form of their environment, i.e. the operator that results from contracting part of the network. This provides physical insight into the limitation of various approaches, and allows us to introduce a new strategy, based on the idea of clusters, that unifies previous methods. The resulting contraction algorithm interpolates naturally between the cheapest and most imprecise and the most costly and most precise method. We benchmark the different algorithms with finite PEPS, and show how the cluster strategy can be used for both the tensor optimization and the calculation of expectation values. Additionally, we discuss its applicability to the parallelization of PEPS and to infinite systems (iPEPS).

Michael Lubasch; J. Ignacio Cirac; Mari-Carmen Bañuls

2014-04-07T23:59:59.000Z

156

Jacobi Elliptic Monopole-Antimonopole Pair Solutions  

E-Print Network (OSTI)

We present new classical generalized Jacobi elliptic one monopole - antimonopole pair (MAP) solutions of the SU(2) Yang-Mills-Higgs theory with the Higgs field in the adjoint representation. These generalized 1-MAP solutions are solved with $\\theta$-winding number $m$=1 and $\\phi$-winding number $n$=1, 2, 3, ... 6. Similar to the generalized Jacobi elliptic one monopole solutions, these generalized 1-MAP solutions are solved by generalizing the large distance behaviour of the solutions to the Jacobi elliptic functions and solving the second order equations of motion numerically when the Higgs potential is vanishing ($\\lambda$=0) and non vanishing ($\\lambda$=1). These generalized 1-MAP solutions possess total energies that are comparable to the total energy of the standard 1-MAP solution with winding number $m$=1. However these total energies are significantly lower than the total energy of the standard 1-MAP solution with winding number $m$=2. All these new generalized solutions are regular numerical finite energy non-BPS solutions of the Yang-Mills-Higgs field theory.

Rosy Teh; Pei-Yen Tan; Khai-Ming Wong

2012-03-02T23:59:59.000Z

157

Properties of an EPR pair If you measure the two halves of an EPR pair using the same basis,  

E-Print Network (OSTI)

Properties of an EPR pair If you measure the two halves of an EPR pair using the same basis, you¨odinger (1935) Motivated by EPR, he introduced the term entanglement (verschr¨ankung). Bell (1964) Bell.g., CHSH) of it? · Can we make EPR pairs from many copies of AB (i.e., n AB)? · Can we use a classical

Shor, Peter W.

158

Beam Head Erosion in Self-Ionized Plasma Wakefield Accelerators  

SciTech Connect

In the recent plasma wakefield accelerator experiments at SLAC, the energy of the particles in the tail of the 42 GeV electron beam were doubled in less than one meter [1]. Simulations suggest that the acceleration length was limited by a new phenomenon--beam head erosion in self-ionized plasmas. In vacuum, a particle beam expands transversely in a distance given by {beta}*. In the blowout regime of a plasma wakefield [2], the majority of the beam is focused by the ion channel, while the beam head slowly spreads since it takes a finite time for the ion channel to form. It is observed that in self-ionized plasmas, the head spreading is exacerbated compared to that in pre-ionized plasmas, causing the ionization front to move backward (erode). A simple theoretical model is used to estimate the upper limit of the erosion rate for a bi-gaussian beam by assuming free expansion of the beam head before the ionization front. Comparison with simulations suggests that half this maximum value can serve as an estimate for the erosion rate. Critical parameters to the erosion rate are discussed.

Berry, M.K.; Blumenfeld, I.; Decker, F.J.; Hogan, M.J.; Ischebeck, R.; Iverson, R.H.; Kirby, N.A.; Siemann, Robert H.; Walz, D.R.; /SLAC; Clayton, C.E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.B.; Zhou, M.; /UCLA; Katsouleas, T.C.; Muggli, P.; Oz, E.; /Southern California U.

2008-01-28T23:59:59.000Z

159

9.01 - Interaction of Ionizing Radiation with Matter  

Science Journals Connector (OSTI)

Abstract The aim of this chapter is to give an overview and try to show how the different interaction probabilities will influence the transport of ionizing radiation through matter. This knowledge is important in different aspects of medical applications of radiation. It has an impact in designing an optimal treatment gantry, in the choice of radiation quality, and of course when determining the absorbed dose distribution in the body. It is also important in diagnostic radiology when optimizing the image quality. Knowledge of the interaction of radiation with matter is also fundamental for understanding the biological effect of radiation and its variation with ionization density. The focus will not be on the basic physics and deriving the different cross sections but on the impact of these cross sections on imaging and therapy in medical physics applications. Ionizing radiation is normally divided into charged particles (previously called directly ionizing radiation) such as leptons, ?-particles, protons and other light ions, and uncharged particles (previously called indirectly ionizing radiation) such as photons (x-rays or ?-rays) and neutrons. This chapter will concentrate on radiation qualities used in radiotherapy, and the main part will be dedicated to electrons and photons with energies up to around 50 MeV and light ions with energies up to 900 MeV per nucleon. The presentation is divided into two main sections, charged particles and photons.

B. Nilsson; A. Brahme

2014-01-01T23:59:59.000Z

160

INDUSTRIAL EFFLUENT TREATMENT USING IONIZING RADIATION COMBINED TO TITANIUM DIOXIDE  

SciTech Connect

The Advanced Oxidation Process (AOP) with OH radicals are the most efficient to mineralize organic compounds, and there are various methods to generate OH radicals as the use of ozone, hydrogen peroxide and ultra-violet radiation and ionizing radiation. The irradiation of aqueous solutions with high-energy electrons results in the excitation and ionizing of the molecules and rapid (10{sup -14} - 10{sup -9} s) formation of reactive intermediates. These reactive species will react with organic compounds present in industrial effluent inducing their decomposition. Titanium dioxide (TiO{sub 2}) catalyzed photoreaction is used to remove a wide range of pollutants in air and water media, combined to UV/VIS light, FeO{sub 2}, and H{sub 2}O{sub 2}, but as far as known there is no report on the combination with ionizing radiation. In some recent studies, the removal of organic pollutants in industrial effluent, such as Benzene, Toluene, and Xylene from petroleum production using ionizing radiation was investigated. It has been ob served that none of the methods can be used individually in wastewater treatment applications with good economics and high degree of energy efficiency. In the present work, the efficiency of ionizing radiation in presence of TiO{sub 2} to treat industrial effluent was evaluated. The main aim to combine these technologies is to improve the efficiency for very hard effluents and to reduce the processing cost for future implementation to large-scale design.

Duarte, C.L.; Oikawa, H.; Mori, M.N.; Sampa, M.H.O.

2004-10-04T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

Muon Pair Creation by a High Energy Electron  

Science Journals Connector (OSTI)

......research-article Articles Muon Pair Creation by a High Energy Electron Takao Yamamoto...cross section for the muon pair creation by an electron...calculated at the incident energy about 1 Bev. At the angles of emitted muons theta+ = theta- 45......

Takao Yamamoto

1962-02-01T23:59:59.000Z

162

Exceptional Lie Algebras, SU(3) and Jordan Pairs  

E-Print Network (OSTI)

A simple unifying view of the exceptional Lie algebras is presented. The underlying Jordan pair content and role are exhibited. Each algebra contains three Jordan pairs sharing the same Lie algebra of automorphisms and the same external su(3) symmetry. Eventual physical applications and implications of the theory are outlined.

Piero Truini

2011-12-06T23:59:59.000Z

163

Density-matrix functionals for pairing in mesoscopic superconductors  

SciTech Connect

A functional theory based on single-particle occupation numbers is developed for pairing. This functional, that generalizes the Bardeen-Cooper-Schrieffer approach, directly incorporates corrections due to particle number conservation. The functional is benchmarked with the pairing Hamiltonian and reproduces perfectly the energy for any particle number and coupling.

Lacroix, Denis; Hupin, Guillaume [GANIL, CEA/DSM-CNRS/IN2P3, BP 55027, 14076 Caen Cedex 5 (France)

2010-10-01T23:59:59.000Z

164

Liquid pair correlations in four spatial dimensions: Theory versus simulation  

E-Print Network (OSTI)

Using liquid integral equation theory, we calculate the pair correlations of particles that interact via a smooth repulsive pair potential in d = 4 spatial dimensions. We discuss the performance of different closures for the Ornstein-Zernike equation, by comparing the results to computer simulation data. Our results are of relevance to understand crystal and glass formation in high-dimensional systems.

M. Heinen; J. Horbach; H. Löwen

2014-11-06T23:59:59.000Z

165

Noise properties of mutually sustained microwave-optoelectronic oscillator pair  

E-Print Network (OSTI)

Noise properties of mutually sustained microwave-optoelectronic oscillator pair E. Shumakher and G microwave-optoelectronic oscillator pair are described. The two oscillators have different spectral purities and exhibits low phase noise and highly suppressed spurious modes. Optoelectronic oscillators are employed

Eisenstein, Gadi

166

LCPHSM2004005 Study of Higgs Boson Pair Production at  

E-Print Network (OSTI)

LC­PHSM­2004­005 March 2004 Study of Higgs Boson Pair Production at Linear Collider K. Desch a , TV for the measurement of the neutral Higgs boson properties within the framework of the MSSM. The process of associated Higgs boson production with subsequent decays of Higgs bosons into b­quark and #­lepton pairs

167

Ionization-Based Multi-directional Flow Sensor  

NLE Websites -- All DOE Office Websites (Extended Search)

Ionization-Based Multi-directional Flow Sensor Ionization-Based Multi-directional Flow Sensor Opportunity The Department of Energy's National Energy Technology Laboratory (NETL) is seeking licensing partners interested in implementing United States Patent Number 7,523,673 entitled "Ionization Based Multi-directional Flow Sensor." Disclosed in this patent is NETL's sensor system and process for multi- directional, real-time monitoring of the flow direction and velocity of a gas stream, with minimal pressure drop, such as air flow in a hybrid power generation system. The sensor comprises an ion source accom- panied by a multidirectional ion collection device near the ion source. Possible applications include power generation and weather monitoring. Overview To optimize the performance of certain industrial processes or apparatus,

168

Resonance enhanced multiphonon ionization of silicon produced during disilane pyrolysis  

Science Journals Connector (OSTI)

Gas phase species generated by thermal decomposition of disilane were studied using resonance enhanced multiphoton ionization at disilane pressures ranging from 1–10 Torr and temperatures ranging from 300–1000 K. Atomic Si mass 28 was observed at 487.9 417.7 and 416.2 nm. A mass?30 signal was not observed between 494–515 nm. Masses 2 32 and 60 were observed using multiphonon ionization and were photoionization fragments from higher silanes and silenes. Thermal decomposition reactions were the main source of atomic Si for the mass?28 signal although ionization of SiH2 and higher silanes followed by fragmentation may have contributed some of the mass?28 signal.

Justine E. Johannes; John G. Ekerdt

1994-01-01T23:59:59.000Z

169

Template:LabelValuePair | Open Energy Information  

Open Energy Info (EERE)

LabelValuePair LabelValuePair Jump to: navigation, search This is the 'LabelValuePair' template. It is typically used to display the results of an ask or sparql query in a simple label: value format. It is used by many pages, including the sub pages for country profiles, and is most frequently called as the template parameter in a query returned as format=template. For more help on this, see Extension:SparqlExtension, Template Help. Parameters label - The label, property or predicate of the query. value - The value or object specified in the query. Usage It should be called in the following format: {{#sparql SELECT ... |format=template |template=LabelValuePair |.. }} Edit the page to see the template text. Retrieved from "http://en.openei.org/w/index.php?title=Template:LabelValuePair&oldid=37488

170

Quantifying Uranium Isotope Ratios Using Resonance Ionization Mass Spectrometry: The Influence of Laser Parameters on Relative Ionization Probability  

SciTech Connect

Resonance Ionization Mass Spectrometry (RIMS) has been developed as a method to measure relative uranium isotope abundances. In this approach, RIMS is used as an element-selective ionization process to provide a distinction between uranium atoms and potential isobars without the aid of chemical purification and separation. We explore the laser parameters critical to the ionization process and their effects on the measured isotope ratio. Specifically, the use of broad bandwidth lasers with automated feedback control of wavelength was applied to the measurement of {sup 235}U/{sup 238}U ratios to decrease laser-induced isotopic fractionation. By broadening the bandwidth of the first laser in a 3-color, 3-photon ionization process from a bandwidth of 1.8 GHz to about 10 GHz, the variation in sequential relative isotope abundance measurements decreased from >10% to less than 0.5%. This procedure was demonstrated for the direct interrogation of uranium oxide targets with essentially no sample preparation. A rate equation model for predicting the relative ionization probability has been developed to study the effect of variation in laser parameters on the measured isotope ratio. This work demonstrates that RIMS can be used for the robust measurement of uranium isotope ratios.

Isselhardt, B H

2011-09-06T23:59:59.000Z

171

Ionized Iron Lines in X-ray Reflection Spectra  

E-Print Network (OSTI)

We present results from new calculations of the X-ray reflection spectrum from ionized accretion discs. These computations improve on our previous models by including the condition of hydrostatic balance in the vertical direction, following the work of Nayakshin, Kazanas & Kallman. We find that an ionized Fe K$\\alpha$ line is prominent in the reflection spectra for a wide variety of physical conditions. The results hold for both gas and radiation pressure dominated discs and when the metal abundances have been varied.

D. R. Ballantyne; R. R. Ross; A. C. Fabian

2001-02-15T23:59:59.000Z

172

Atmospheric Pressure Photoionization Mass Spectrometry. Ionization Mechanism and the Effect of Solvent on the Ionization of Naphthalenes  

Science Journals Connector (OSTI)

13,14 To date, APPI-MS has been successfully used in the analysis of flavonoids,15 steroids,16,17 vitamins,18 antioxidants,19 pharmaceuticals,20-22 polyaromatic hydrocarbons,23,24 agrochemicals,25 and aromatic imines and amines. ... The ionization process in APPI directly depends on the reactant ion composition, which in turn depends on solvent, dopant, nebulizing gas, auxiliary gas, and impurities as well as components of the surrounding air. ... Next, the ionization efficiency and mechanism in APPI was studied with 7 naphthalenes in the same 13 solvent compositions. ...

Tiina J. Kauppila; Tiia Kuuranne; Eduardo C. Meurer; Marcos N. Eberlin; Tapio Kotiaho; Risto Kostiainen

2002-09-28T23:59:59.000Z

173

Coulomb Drag at ?=12: Composite Fermion Pairing Fluctuations  

Science Journals Connector (OSTI)

We consider the Coulomb drag between two two-dimensional electron layers at filling factor ?=12 each, using a strong-coupling approach within the composite fermion picture. Because of an attractive interlayer interaction, composite fermions are expected to form a paired state below a critical temperature Tc. We find that above Tc pairing fluctuations make the longitudinal transresistivity ?D increase with decreasing temperature. The pairing mechanism we study is very sensitive to density variations in the two layers, and to an applied current. We discuss a possible relation to an experiment by Lilly et al. [Phys. Rev. Lett. 80, 1714 (1998)].

Iddo Ussishkin and Ady Stern

1998-11-02T23:59:59.000Z

174

QED peripheral mechanism of pair production at colliders  

SciTech Connect

Cross sections of the processes of production of neutral pions and pairs of charged fermions and bosons in peripheral interaction of leptons and photons are calculated in the main logarithmic approximation. We investigate the phase volumes and differential cross sections. The differential cross sections of production of a few neutral pions and a few pairs are written down explicitly. Considering the academic problem of summation over a number of pairs for massless particles we reproduce the known results obtained in the 1970s. The possibility of constructing the generator for Monte Carlo modeling of these processes based on these results is discussed.

Ahmadov, A. I.; Galynskii, M. V.; Bystritskiy, Yu. M.; Kuraev, E. A.; Shatnev, M. G. [Joint Institute for Nuclear Research, Dubna, Russia, and Institute of Physics, Azerbaijan National Academy of Sciences, Baku (Azerbaijan); Institute of Physics, Minsk (Belarus); Joint Institute for Nuclear Research, Dubna (Russian Federation); Kharkov Institute of Physics and Technology, Kharkov, 61108 (Ukraine)

2008-10-01T23:59:59.000Z

175

Effective field theory for dilute fermions with pairing  

SciTech Connect

Effective field theory (EFT) methods for a uniform system of fermions with short-range, natural interactions are extended to include pairing correlations, as part of a program to develop a systematic Kohn-Sham density functional theory (DFT) for medium and heavy nuclei. An effective action formalism for local composite operators leads to a free-energy functional that includes pairing by applying an inversion method order by order in the EFT expansion. A consistent renormalization scheme is demonstrated for the uniform system through next-to-leading order, which includes induced-interaction corrections to pairing.

Furnstahl, R.J. [Department of Physics, Ohio State University, Columbus, OH 43210 (United States)], E-mail: furnstahl.1@osu.edu; Hammer, H.-W. [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie), Universitaet Bonn, Nussallee 14-16, D-53115 Bonn (Germany)], E-mail: hammer@itkp.uni-bonn.de; Puglia, S.J. [SBIG PLC, Berkeley Square House, London W1J 6BR (United Kingdom)], E-mail: spuglia@sbiguk.com

2007-11-15T23:59:59.000Z

176

Pairs Emission in a Uniform Background Field: an Algebraic Approach  

E-Print Network (OSTI)

A fully algebraic general approach is developed to treat the pairs emission and absorption in the presence of some uniform external background field. In particular, it is shown that the pairs production and annihilation operators, together with the pairs number operator, do actually fulfill the SU(2) functional Lie algebra. As an example of application, the celebrated Schwinger formula is consistently and nicely recovered, within this novel approach, for a Dirac spinor field in the presence of a constant and homogeneous electric field in four spacetime dimensions.

Roberto Soldati

2011-06-23T23:59:59.000Z

177

Can a wormhole be interpreted as an EPR pair?  

E-Print Network (OSTI)

Recently, Maldacena and Susskind arXiv:1306.0533 and Jensen and Karch arXiv:1307.1132 argued that a wormhole can be interpreted as an EPR pair. We point out that a convincing justification of such an interpretation would require a quantitative evidence that correlations between two ends of the wormhole are equal to those between the members of the EPR pair. As long as the existing results do not contain such evidence, the interpretation of wormhole as an EPR pair does not seem justified.

Nikolic, H

2013-01-01T23:59:59.000Z

178

Pairing states of superfluid He3 in uniaxially anisotropic aerogel  

Science Journals Connector (OSTI)

Stable pairing states of superfluid He3 in aerogel are examined in the case with a global uniaxial anisotropy which may be created by applying a uniaxial stress to the aerogel. Due to such a global anisotropy, the stability region of an Anderson-Brinkman-Morel (ABM) pairing state becomes wider. In a uniaxially stretched aerogel, the pure polar pairing state with a horizontal line node is predicted to occur, as a three-dimensional superfluid phase, over a measurable width just below the superfluid transition at Tc(P). A possible relevance of the present results to the case with no global anisotropy is also discussed.

Kazushi Aoyama and Ryusuke Ikeda

2006-02-16T23:59:59.000Z

179

Plasma ionization by annularly bounded helicon waves Masayuki Yanoa  

E-Print Network (OSTI)

Plasma ionization by annularly bounded helicon waves Masayuki Yanoa and Mitchell L. R. Walkerb and magnetic fields is derived with respect to the boundary conditions of a coaxial helicon plasma source by comparison with the standard cylindrical helicon plasma source. Further, a parametric study of source length

Walker, Mitchell

180

Optically-ionized plasma recombination x-ray lasers  

SciTech Connect

Design studies for recombination x-ray lasers based on plasmas ionized by high intensity, short pulse optical lasers are presented. Transient lasing on n = 3 to n = 2 transitions in Lithium-like Neon allows for moderately short wavelengths ({le} 100{angstrom}) without requiring ionizing intensities associated with relativistic electron quiver energies. The electron energy distribution following the ionizing pulse affects directly the predicted gains for this resonance transition. Efficiencies of 10{sup {minus}6} or greater are found for plasma temperatures in the vicinity of 40 eV. Simulation studies of parametric heating phenomena relating to stimulated Raman and Compton scattering are presented. For electron densities less than about 2.5 {times} 10{sup 20} cm{sup {minus}3} and peak driver intensity of 2 {times} 10{sup 17} W/cm{sup 2} at 0.25 {mu}m with pulse length of 100 fsec, the amount of electron heating is found to be marginally significant. For Lithium-like Aluminum, the required relativistic ionizing intensity gives excessive electron heating and reduced efficiency, thereby rendering this scheme impractical for generating shorter wavelength lasing ({le} 50{angstrom}) in the transient case. Following the transient lasing phase, a slow hydrodynamic expansion into the surrounding cool plasma is accompanied by quasi-static gain on the n = 4 to n = 3 transition in Lithium-like Neon. Parametric heating effects on gain optimization in this regime are also discussed. 18 refs., 6 figs.

Amendt, P.; Eder, D.C.; Wilks, S.C.; Dunning, M.J.; Keane, C.J.

1991-01-18T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

An Electrospray Ionization Source for Integration with Microfluidics  

Science Journals Connector (OSTI)

An Electrospray Ionization Source for Integration with Microfluidics ... Mass spectrometry plays a key role in such analysis, and there are many advantages in efficiency and sample consumption that can be attained by the use of microfluidics. ... Digital Microfluidics with In-Line Sample Purification for Proteomics Analyses with MALDI-MS ...

Jun Kameoka; Reid Orth; Bojan Ilic; David Czaplewski; Tim Wachs; H. G. Craighead

2002-10-22T23:59:59.000Z

182

Cell cycle responses to low-dose ionizing radiation.  

Science Journals Connector (OSTI)

...47, 2006] 5178 Low-dose hyper-radiosensitivity...radiosensitivity of cells to doses of ionizing radiation less than 0.5 Gy...connection between low-dose HRS survival, Ataxia...the low dose radiation range (0-1 Gy). MR4 cells...

Sarah A. Krueger; George D. Wilson; Michael C. Joiner; and Brian Marples

2006-04-15T23:59:59.000Z

183

The Inactivation of $\\alpha$-Chymotrypsin by Ionizing Radiations  

Science Journals Connector (OSTI)

...Chymotrypsin by Ionizing Radiations J. A. V. Butler...studied over a range of concentrations...where D is the dose required to cause...air over a wide range of concentrations...by varying the dose rate of the electron...over a very wide range. An enhanced...

1960-01-01T23:59:59.000Z

184

Sensitivity of aflatoxin b1 to ionizing radiation.  

Science Journals Connector (OSTI)

...activity with respective doses of 2.5, 5, 10...irradiation aflatoxin B1 dose of: in upper layediteionre...in foodstuffs may range from levels of 0...with an irradiation dose of10 kGy (the maximum...its sensitivity to ionizing radiation. When aflatoxin...

P J Van Dyck; P Tobback; M Feyes; H van de Voorde

1982-06-01T23:59:59.000Z

185

Toxicity of Pasteurella tularensis Killed by Ionizing Radiation  

Science Journals Connector (OSTI)

...to 106 r of y-radiation. When injected...suspension. Lethal doses of newly prepared...by exposure to ionizing radia- tion induced...to 106 r of y-radiation from a 60Co source at a dose rate of approximately...only in a limited range of dilutions...

Marshall E. Landay; George G. Wright; James D. Pulliam; Milton J. Finegold

1968-09-01T23:59:59.000Z

186

Project Lyman: Quantifying 11 Gyrs of Metagalactic Ionizing Background Evolution  

E-Print Network (OSTI)

The timing and duration of the reionization epoch is crucial to the emergence and evolution of structure in the universe. The relative roles that star-forming galaxies, active galactic nuclei and quasars play in contributing to the metagalactic ionizing background across cosmic time remains uncertain. Deep quasar counts provide insights into their role, but the potentially crucial contribution from star-formation is highly uncertain due to our poor understanding of the processes that allow ionizing radiation to escape into the intergalactic medium (IGM). The fraction of ionizing photons that escape from star-forming galaxies is a fundamental free parameter used in models to "fine-tune" the timing and duration of the reionization epoch that occurred somewhere between 13.4 and 12.7 Gyrs ago (redshifts between 12 > z > 6). However, direct observation of Lyman continuum (LyC) photons emitted below the rest frame \\ion{H}{1} ionization edge at 912 \\AA\\ is increasingly improbable at redshifts z > 3, due to the stead...

McCandliss, Stephan R; Bergvall, Nils; Bianchi, Luciana; Bridge, Carrie; Bogosavljevic, Milan; Cohen, Seth H; Deharveng, Jean-Michel; Dixon, W Van Dyke; Ferguson, Harry; Friedman, Peter; Hayes, Matthew; Howk, J Christopher; Inoue, Akio; Iwata, Ikuru; Kaiser, Mary Elizabeth; Kriss, Gerard; Kruk, Jeffrey; Kutyrev, Alexander S; Leitherer, Claus; Meurer, Gerhardt R; Prochaska, Jason X; Sonneborn, George; Stiavelli, Massimo; Teplitz, Harry I; Windhorst, Rogier A

2012-01-01T23:59:59.000Z

187

High resolution resonance ionization imaging detector and method  

DOE Patents (OSTI)

A resonance ionization imaging device (RIID) and method for imaging objects using the RIID are provided, the RIID system including a RIID cell containing an ionizable vapor including monoisotopic atoms or molecules, the cell being positioned to intercept scattered radiation of a resonance wavelength .lambda..sub.1 from the object which is to be detected or imaged, a laser source disposed to illuminate the RIID cell with laser radiation having a wavelength .lambda..sub.2 or wavelengths .lambda..sub.2, .lambda..sub.3 selected to ionize atoms in the cell that are in an excited state by virtue of having absorbed the scattered resonance laser radiation, and a luminescent screen at the back surface of the RIID cell which presents an image of the number and position of charged particles present in the RIID cell as a result of the ionization of the excited state atoms. The method of the invention further includes the step of initially illuminating the object to be detected or imaged with a laser having a wavelength selected such that the object will scatter laser radiation having the resonance wavelength .lambda..sub.1.

Winefordner, James D. (Gainesville, FL); Matveev, Oleg I. (Gainesville, FL); Smith, Benjamin W. (Gainesville, FL)

1999-01-01T23:59:59.000Z

188

Parametric-resonance ionization cooling of muon beams  

SciTech Connect

Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a high-luminosity muon collider. Combining muon ionization cooling with parametric resonant dynamics should allow an order of magnitude smaller final equilibrium transverse beam emittances than conventional ionization cooling alone. In this scheme, a half-integer parametric resonance is induced in a cooling channel causing the beam to be naturally focused with the period of the channel's free oscillations. Thin absorbers placed at the focal points then cool the beam's angular divergence through the usual ionization cooling mechanism where each absorber is followed by RF cavities. A special continuous-field twin-helix magnetic channel with correlated behavior of the horizontal and vertical betatron motions and dispersion was developed for PIC. We present the results of modeling PIC in such a channel using GEANT4/G4beamline. We discuss the challenge of precise beam aberration control from one absorber to another over a wide angular spread.

Morozov, V. S.; Derbenev, Ya. S.; Afanasev, A.; Johnson, R. P.; Erdelyi, B.; Maloney, J. A. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Muons, Inc., Batavia, Illinois 60510 (United States) and George Washington University, Washington, D.C. 20052 (United States); Muons, Inc., Batavia, Illinois 60510 (United States); Northern Illinois University, DeKalb, Illinois 60115 (United States)

2012-12-21T23:59:59.000Z

189

Parametric-Resonance Ionization Cooling of Muon Beams  

SciTech Connect

Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a high-luminosity muon collider. Combining muon ionization cooling with parametric resonant dynamics should allow an order of magnitude smaller final equilibrium transverse beam emittances than conventional ionization cooling alone. In this scheme, a half-integer parametric resonance is induced in a cooling channel causing the beam to be naturally focused with the period of the channel's free oscillations. Thin absorbers placed at the focal points then cool the beam?s angular divergence through the usual ionization cooling mechanism where each absorber is followed by RF cavities. A special continuous-field twin-helix magnetic channel with correlated behavior of the horizontal and vertical betatron motions and dispersion was developed for PIC. We present the results of modeling PIC in such a channel using GEANT4/ G4 beamline. We discuss the challenge of precise beam aberration control from one absorber to another over a wide angular spread.

Morozov, V. S. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Derbenev, Ya. S. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Afanasev, A. [Muons, Inc., Batavia, IL (United States) and George Washington University, Washington, D.C. (United States); Johnson, R. P. [Muons, Inc., Batavia, IL (United States); Erdelyi, B. [Northern Illinois University, DeKalb, IL (United States); Maloney, J. A. [Northern Illinois University, DeKalb, IL (United States)

2012-12-01T23:59:59.000Z

190

Femtosecond laser nanomachining initiated by ultraviolet multiphoton ionization  

E-Print Network (OSTI)

Femtosecond laser nanomachining initiated by ultraviolet multiphoton ionization Xiaoming Yu,1) femtosecond laser pulse initiated by an ultraviolet (UV) pulse. With both pulses at a short (~60 fs) delay.g. XUV and X-ray, with the required fluence below their normal threshold. ©2013 Optical Society

Van Stryland, Eric

191

Recent Advances in Thermionic Ionization Detection for Gas Chromatography  

Science Journals Connector (OSTI)

......and catalytic combustion modifier/thermionic...be comparable to hydrocarbons by a judicious selection...because the flame heat w o u l d otherwise...elec tronegative combustion products by means...the bulk o f the hydrocarbon ionization pro duced...The applications data presented in this......

P.L. Patterson

1986-02-01T23:59:59.000Z

192

production under ionizing radiation in aluminoborosilicate glasses by EPR spectroscopy.  

E-Print Network (OSTI)

1 Ti3+ production under ionizing radiation in aluminoborosilicate glasses by EPR spectroscopy. P irradiation of Ti4+ ions in aluminoborosilicate glasses have been studied by EPR spectroscopy at 20 K of the Ti3+ ion EPR spectra has shown three different Ti3+ environment attributed to one [VI] Ti3+ and two

Paris-Sud XI, Université de

193

Matrixassisted laser desorption/ionization mass spectrometric analysis of aliphatic biodegradable photoluminescent polymers  

E-Print Network (OSTI)

established that the new ILMs provided good spottospot reproducibility and high ionization efficiency compared/ionization mass spectrometry (MALDIMS). The polymers, formed by a condensation reaction of three components

Yang, Jian

194

Characterization of Cell Cycle Checkpoint Responses after Ionizing Radiation in Nijmegen Breakage Syndrome Cells  

Science Journals Connector (OSTI)

...events leading to G, and G2 arrests following ionizing radiation is abnormal in cells from AT patients. p53 protein up- regulation following low doses of ionizing radiation ranges from delayed and reduced to completely absent...

Vikky Yamazaki; Rolf-Dieter Wegner; and Cordula U. Kirchgessner

1998-06-01T23:59:59.000Z

195

Enhanced Sensitivity of the RET Proto-Oncogene to Ionizing Radiation In vitro  

Science Journals Connector (OSTI)

...the RET sensitivity to ionizing radiation exposure, and to elucidate...were first exposed to ionizing radiation, electrophoresed in...Table 1 Table 1. Range of tail moment in non...for comet Radiation dose Cell line Range of tail...

Claudia Béu Volpato; Minerva Martínez-Alfaro; Raffaella Corvi; Coralie Gabus; Sylvie Sauvaigo; Pietro Ferrari; Elena Bonora; Alessandro De Grandi; and Giovanni Romeo

2008-11-01T23:59:59.000Z

196

Extremely Low Dose Ionizing Radiation Up-regulates CXC Chemokines in Normal Human Fibroblasts  

Science Journals Connector (OSTI)

...with radiation exposure (1). Ionizing radiation at moderate and higher doses (0.1-10 Gy) can produce DNA strand...death. Studies of mutants sensitive to ionizing radiation at this range of doses have revealed that the responsible genes...

Akira Fujimori; Ryuichi Okayasu; Hiroshi Ishihara; Satoshi Yoshida; Kiyomi Eguchi-Kasai; Kumie Nojima; Satoru Ebisawa; and Sentaro Takahashi

2005-11-15T23:59:59.000Z

197

Nonlinear dynamics of ionization stabilization of atoms in intense laser fields  

E-Print Network (OSTI)

We revisit the stabilization of ionization of atoms subjected to a superintense laser pulse using nonlinear dynamics. We provide an explanation for the lack of complete ionization at high intensity and for the decrease of the ionization probability as intensity is increased. We investigate the role of each part of the laser pulse (ramp-up, plateau, ramp-down) in this process. We emphasize the role of the choice for the ionization criterion, energy versus distance criterion.

Michael Norman; C. Chandre; T. Uzer; Peijie Wang

2014-12-06T23:59:59.000Z

198

Covariant Wave Function Reduction and Coherent Decays of Kaon Pair  

E-Print Network (OSTI)

The recently developed relativistically covariant formulation of wave function reduction is illustrated for Lipkin's proposal to study CP violation in the coherent decay of kaon pairs. Covariant results are obtained in agreement with an amplitude approach proposed in the literature.

Bernd A. Berg

1998-09-12T23:59:59.000Z

199

Signed-Rank Tests for Censored Matched Pairs  

E-Print Network (OSTI)

Z . (1967), The Theory of Rank Tests, New York: AcademicT. R. (1982), " A Class of Rank Test Procedures for Censored1983), " A Modified Wilcoxon Rank Sum Test for Paired Data,"

Dorota M. Dabrowska

2011-01-01T23:59:59.000Z

200

On the Anonymity of Home/Work Location Pairs  

E-Print Network (OSTI)

On the Anonymity of Home/Work Location Pairs Philippe Golle and Kurt Partridge Palo Alto Research population is 1, 21 and 34,980, for locations known at the granularity of a census block, census track

Golle, Philippe

Note: This page contains sample records for the topic "ionization brems pair" 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

Macro-coherent two photon and radiative neutrino pair emission  

E-Print Network (OSTI)

We discuss a possibility of detecting a coherent photon pair emission and related radiative neutrino pair emission from excited atoms. It is shown that atoms of lambda- and ladder-type three level system placed in a pencil-like cylinder give a back to back emission of two photons of equal energy $\\Delta/2$, sharply peaked with a width $\\propto $ 1/(target size) and well collimated along the cylinder axis. This process has a measurable rate $\\propto$ (target number density) $^2 \\times$ target volume, while a broader spectral feature of one-photon distribution separated by (mass sum of a neutrino pair)$^2/(2\\Delta)$ from the two photon peak may arise from radiative neutrino pair emission, with a much smaller rate.

M. Yoshimura; C. Ohae; A. Fukumi; K. Nakajima; I. Nakano; H. Nanjo; N. Sasao

2008-05-14T23:59:59.000Z

202

Top quark pair cross section prospects in ATLAS  

E-Print Network (OSTI)

The observation of the top quark will be an important milestone in ATLAS. This talk reviews methods that ATLAS plans to use to observe the top quark pair production process and measure its cross section.

Andrei Gaponenko; for the ATLAS Collaboration

2009-10-20T23:59:59.000Z

203

Paired Straight Hearth Furnace-Transformational Ironmaking Process  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

based on the Paired Straight Hearth Furnace (PSH) for iron ore reduction y PSH is a coal and natural gas coke-free process most suitable for American fine concentrates y PSH...

204

Formation of Cooper pairs as a consequence of exchange interaction  

E-Print Network (OSTI)

Pairing of two electrons with antiparallel spins may lead to energy minimization of each of the paired electrons. Thus the exchange interaction causes a bond between two valence electrons in a crystal. This can be proved analyzing the energy of each valence electron in the field of the one-valent metallic crystal on assumption that all other kinds of magnetic spin ordering in the crystal are negligible.

Dolgopolov, Stanislav

2015-01-01T23:59:59.000Z

205

CP violation in fermion pair decays of neutral boson particles  

Science Journals Connector (OSTI)

We study CP violation in fermion pair decays of neutral boson particles with spin 0 or 1. We study a new asymmetry to measure CP violation in ?, KL??+?- decays and discuss the possibility of measuring it experimentally. For the spin-1 particles case, we study CP violation in the decays of J/? to SU(3) octet baryon pairs. We show that these decays can be used to put stringent constraints on the electric dipole moments of ?, ?, and ?.

Xiao-Gang He; J. P. Ma; Bruce McKellar

1994-05-01T23:59:59.000Z

206

Possibility of Prolific Pair Production with High-Power Lasers  

SciTech Connect

Prolific electron-positron pair production is possible at laser intensities approaching 10{sup 24} W cm{sup -2} at a wavelength of 1 {mu}m. An analysis of electron trajectories and interactions at the nodes (B=0) of two counterpropagating, circularly polarized laser beams shows that a cascade of {gamma} rays and pairs develops. The geometry is generalized qualitatively to linear polarization and laser beams incident on a solid target.

Bell, A. R.; Kirk, John G. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom) and STFC Central Laser Facility, RAL, Didcot, OX11 0QX (United Kingdom); Max-Planck-Institut fuer Kernphysik, Saupfercheckweg, 1, D-69117, Heidelberg (Germany)

2008-11-14T23:59:59.000Z

207

Formation of Cooper pairs as a consequence of exchange interaction  

E-Print Network (OSTI)

Pairing of two electrons with antiparallel spins may lead to energy minimization of each of the paired electrons. Thus the exchange interaction causes a bond between two valence electrons in a crystal. This can be proved analyzing the energy of each valence electron in the field of the one-valent metallic crystal on assumption that all other kinds of magnetic spin ordering in the crystal are negligible.

Stanislav Dolgopolov

2015-01-15T23:59:59.000Z

208

Physiological Responses of the Hyperthermophilic Archaeon “Pyrococcus abyssi” to DNA Damage Caused by Ionizing Radiation  

Science Journals Connector (OSTI)

...Damage Caused by Ionizing Radiation Edmond Jolivet 1 Corresponding...Fukuoka 812-8581, Japan The mechanisms by which...temperature and/or ionizing radiation. The hyperthermophilic...Matsunaga thanks the Japan Society for the Promotion...resistant to ionizing radiation? Trends Microbiol...

Edmond Jolivet; Fujihiko Matsunaga; Yoshizumi Ishino; Patrick Forterre; Daniel Prieur; Hannu Myllykallio

2003-07-01T23:59:59.000Z

209

Ionizing Radiation-induced, Mitochondria-dependent Generation of Reactive Oxygen/Nitrogen  

Science Journals Connector (OSTI)

...exposing cells to ionizing radiation. In the 1-10 Gy dose range, the amount...demonstrated that ionizing radiation in the therapeutic dose range stimulates a...exposing cells to ionizing radiation. In the 1-10 Gy dose range, the amount...

J. Kevin Leach; Glenn Van Tuyle; Peck-Sun Lin; Rupert Schmidt-Ullrich; and Ross B. Mikkelsen

2001-05-15T23:59:59.000Z

210

Physical and biological properties of U.S. standard endotoxin EC after exposure to ionizing radiation.  

Science Journals Connector (OSTI)

...in the UV range, radiation treatment...pattern. Dose-related...effects of the ionizing radiation...milligram-per-milliliter range) (13...in the UV range, we found...ioniz- ing radiation. Regarding...effective, dose- dependent...EXPOSED TO IONIZING RADIATION...

G Csako; R J Elin; H D Hochstein; C M Tsai

1983-07-01T23:59:59.000Z

211

MACHINE LEARNING FOR IDENTIFICATION OF SOURCES OF IONIZING RADIATION DURING SPACE MISSIONS  

E-Print Network (OSTI)

MACHINE LEARNING FOR IDENTIFICATION OF SOURCES OF IONIZING RADIATION DURING SPACE MISSIONS Ricardo for the automated identification and classification of tracks of ionizing radiation during space missions. The tracks of ionizing radiation are mea- sured by the hybrid semiconductor Medipix2 pixel de- tector system

Vilalta, Ricardo

212

Discovering Clinical Biomarkers of Ionizing Radiation Exposure with Serum Proteomic Analysis  

Science Journals Connector (OSTI)

...with a wide range of diagnoses and radiation treatment...and during ionizing radiation...from low dose-volume...of a wide range of diagnoses...volume, and dose of radiotherapy...exposed to ionizing radiation between the...with a wide range of diagnoses and radiation treatment...and during ionizing radiation...from low dose-volume...

Cynthia Ménard; Donald Johann; Mark Lowenthal; Thierry Muanza; Mary Sproull; Sally Ross; James Gulley; Emanuel Petricoin; C. Norman Coleman; Gordon Whiteley; Lance Liotta; and Kevin Camphausen

2006-02-01T23:59:59.000Z

213

Ionizing Radiation Effects on CMOS Imagers Manufactured in Deep Submicron Process  

E-Print Network (OSTI)

, ionizing radiation, total dose, dark current, STI, hardening by design, RHDB 1. INTRODUCTION IonizingIonizing Radiation Effects on CMOS Imagers Manufactured in Deep Submicron Process Vincent Goiffona a large dynamic range. This can significantly impact the radiation hardness of "in-pixel" devices which

Mailhes, Corinne

214

From an insulating to a superfluid pair-bond liquid  

Science Journals Connector (OSTI)

We study an exchange coupled system of itinerant electrons and localized fermion pairs resulting in a resonant pairing formation. This system inherently contains resonating fermion pairs on bonds that lead to a superconducting phase, provided that long-range phase coherence between their constituents can be established. The prerequisite is that the resonating fermion pairs can become itinerant. This is rendered possible through the emergence of two kinds of bond fermions: individual and composite fermions made of one individual electron attached to a bound pair on a bond. If the strength of the exchange coupling exceeds a certain value, then the superconducting ground state undergoes a quantum phase transition into an insulating pair-bond liquid state. The gap of the superfluid phase thereby goes over continuously into a charge gap of the insulator. The changeover from the superconducting to the insulating phase is accompanied by a corresponding qualitative modification of the dispersion of the two kinds of fermionic excitations. Using a bond operator formalism, we derive the phase diagram of such a scenario together with the elementary excitations characterizing the various phases as a function of the exchange coupling and the temperature.

M. Cuoco and J. Ranninger

2006-09-20T23:59:59.000Z

215

Propagation direction reversal of ionization zones in the transition between high and low current magnetron sputtering  

SciTech Connect

Past research has revealed the propagation of dense, asymmetric ionization zones in both high and low current magnetron discharges. Here we report about the direction reversal of ionization zone propagation as observed with fast cameras. At high currents, zones move in the E B direction with velocities of 103 to 104 m/s. However at lower currents, ionization zones are observed to move in the opposite, the -E B direction, with velocities ~;; 103 m/s. It is proposed that the direction reversal is associated with the local balance of ionization and supply of neutrals in the ionization zone.

School of Materials Science and Engineering, State Key Lab for Materials Processing and Die & Mold Technology, Huazhong University of Science and Technology, Wuhan 430074, China; Department of Physics, University of California Berkeley, Berkeley, California 94720, USA; Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA; Yang, Yuchen; Liu, Jason; Liu, Lin; Anders, André

2014-12-11T23:59:59.000Z

216

Low Dose Radiation Research Program: Research Highlights - Ionizing  

NLE Websites -- All DOE Office Websites (Extended Search)

Affects Cancer Frequency and Characteristics by Acting Affects Cancer Frequency and Characteristics by Acting on the Microenvironment Background: For more than a quarter century the scientific rationale for extrapolating radiation health effects has been underpinned by biophysical target theory. Fundamental to target theory is that the effect (e.g., DNA damage, mutation, cancer) is proportional to dose based on interaction of energy with biological targets, specifically DNA. However, the biology following ionizing radiation is more than just DNA damage, repair, or misrepair. Cellular responses to ionizing radiation can affect phenotype, cell interactions, lineage commitment, differentiation and genomic stability, all of which have been widely documented in cultured cells and many observed in vivo. This class of non-targeted effects induced

217

Low dose ionizing radiation induces tumor growth promoting factors in  

NLE Websites -- All DOE Office Websites (Extended Search)

ionizing radiation induces tumor growth promoting factors in ionizing radiation induces tumor growth promoting factors in stress-induced premature senescent fibroblasts David Boothman University of Texas Southwestern Medical Center at Dallas Abstract Recent evidence suggest that the causes of cancer development are not limited to mutations within cancer cells, but also involve in alterations of cancer microenvironment. Senescent cells are irreversibly growth arrested, but remain metabolically active. Senescent cells, especially senescent fibroblasts in the stroma may provide a beneficial environment for tumor growth through secretion of certain factors. Accumulation of senescent cells in the stroma of patients repeatedly exposed to low doses of IR or low dose rates of IR, could be an important factor, causing alteration of the microenvironment that ultimately benefits tumor

218

Ionic Liquids and Ionizing Radiation: Reactivity of Highly Energetic  

NLE Websites -- All DOE Office Websites (Extended Search)

Ionizing Radiation: Reactivity of Highly Energetic Ionizing Radiation: Reactivity of Highly Energetic Species James F. Wishart J. Phys. Chem. Lett. 1, 3225-3231 (2010). [Find paper at ACS Publications] or use ACS Articles on Request View the video on this Perspective article at The Journal of Physical Chemistry Letters (5:03) Selected for the ACS Special Virtual Issue on Ionic Liquids (March 2011). Abstract: Due to their unique properties, ionic liquids present many opportunities for basic research on the interactions of radiation with materials under conditions not previously available. At the same time, there are practical applied reasons for characterizing, understanding, and being able to predict how ionic-liquid-based devices and industrial-scale systems will perform under conditions of extreme reactivity, including radiation. This

219

Oxidative Stress and Skeletal Health with Low Dose, Ionizing Radiation  

NLE Websites -- All DOE Office Websites (Extended Search)

Oxidative Stress and Skeletal Health with Low Dose, Ionizing Radiation Oxidative Stress and Skeletal Health with Low Dose, Ionizing Radiation Globus Ruth NASA Ames Research Center Abstract Osteoporosis profoundly affects the aging U.S. population and exposure to high doses of radiation causes bone loss similar to age-related osteoporosis, although the influence of low dose radiation exposures is not known. The central hypothesis of our DOE project (NASA supplement) is that low doses of radiation modulate subsequent skeletal degeneration via oxidative pathways. Our working hypothesis is that a prior exposure to low dose radiation regulates oxidative metabolism within bone and contributes to bone loss caused either by subsequent high, challenge doses of radiation or by aging. HZE source: Because astronauts are exposed to radiation from GCR and solar

220

Detection of single atoms by resonance ionization spectroscopy  

SciTech Connect

Rutherford's idea for counting individual atoms can, in principle, be implemented for nearly any type of atom, whether stable or radioactive, by using methods of resonance ionization. With the RIS technique, a laser is tuned to a wavelength which will promote a valence electron in a Z-selected atom to an excited level. Additional resonance or nonresonance photoabsorption steps are used to achieve nearly 100% ionization efficiencies. Hence, the RIS process can be saturated for the Z-selected atoms; and since detectors are available for counting either single electrons or positive ions, one-atom detection is possible. Some examples are given of one-atom detection, including that of the noble gases, in order to show complementarity with AMS methods. For instance, the detection of /sup 81/Kr using RIS has interesting applications for solar neutrino research, ice-cap dating, and groundwater dating. 39 refs., 7 figs., 2 tabs.

Hurst, G.S.

1986-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

COSMIC RAY HEATING OF THE WARM IONIZED MEDIUM  

SciTech Connect

Observations of line ratios in the Milky Way's warm ionized medium suggest that photoionization is not the only heating mechanism present. For the additional heating to explain the discrepancy, it would have to have a weaker dependence on the gas density than the cooling rate, {Lambda}n{sub e}{sup 2}. Reynolds et al. suggested turbulent dissipation or magnetic field reconnection as possible heating sources. We investigate here the viability of MHD-wave mediated cosmic ray heating as a supplemental heating source. This heating rate depends on the gas density only through its linear dependence on the Alfven speed, which goes as n{sub e}{sup -1/2}. We show that, scaled to appropriate values of cosmic ray energy density, cosmic ray heating can be significant. Furthermore, this heating is stable to perturbations. These results should also apply to warm ionized gas in other galaxies.

Wiener, Joshua; Peng Oh, S. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States)] [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Zweibel, Ellen G. [Departments of Astronomy and Physics, and Center for Magnetic Self-Organization, University of Wisconsin-Madison, Madison, WI 53706 (United States)] [Departments of Astronomy and Physics, and Center for Magnetic Self-Organization, University of Wisconsin-Madison, Madison, WI 53706 (United States)

2013-04-10T23:59:59.000Z

222

Aerodynamic Effects in Weakly Ionized Gas: Phenomenology and Applications  

SciTech Connect

Aerodynamic effects in ionized gases, often neglected phenomena, have been subject of a renewed interest in recent years. After a brief historical account, we discuss a selected number of effects and unresolved problems that appear to be relevant in both aeronautic and propulsion applications in subsonic, supersonic, and hypersonic flow. Interaction between acoustic shock waves and weakly ionized gas is manifested either as plasma-induced shock wave dispersion and acceleration or as shock-wave induced double electric layer in the plasma, followed by the localized increase of the average electron energy and density, as well as enhancement of optical emission. We describe the phenomenology of these effects and discuss several experiments that still do not have an adequate interpretation. Critical for application of aerodynamic effects is the energy deposition into the flow. We classify and discuss some proposed wall-free generation schemes with respect to the efficiency of energy deposition and overall generation of the aerodynamic body force.

Popovic, S.; Vuskovic, L. [Department of Physics, Old Dominion University, Norfolk, Virginia (United States)

2006-12-01T23:59:59.000Z

223

Subcellular analysis by laser ablation electrospray ionization mass spectrometry  

DOE Patents (OSTI)

In various embodiments, a method of laser ablation electrospray ionization mass spectrometry (LAESI-MS) may generally comprise micro-dissecting a cell comprising at least one of a cell wall and a cell membrane to expose at least one subcellular component therein, ablating the at least one subcellular component by an infrared laser pulse to form an ablation plume, intercepting the ablation plume by an electrospray plume to form ions, and detecting the ions by mass spectrometry.

Vertes, Akos; Stolee, Jessica A; Shrestha, Bindesh

2014-12-02T23:59:59.000Z

224

Observation of ionization fronts in low density foam targets  

SciTech Connect

Ionization fronts have been observed in low density chlorinated foam targets and low density foams confined in gold tubes using time resolved {ital K}-shell absorption spectroscopy. The front was driven by an intense pulse of soft x-rays produced by high power laser irradiation. The density and temperature profiles inferred from the radiographs provided detailed measurement of the conditions. The experimental data were compared to radiation hydrodynamics simulations and reasonable agreement was obtained. {copyright} {ital 1999 American Institute of Physics.}

Hoarty, D. [Imperial College of Science, Technology and Medicine, London (United Kingdom)] [Imperial College of Science, Technology and Medicine, London (United Kingdom); [Radiation Physics Department, AWE Aldermaston, Reading, Berkshire (United Kingdom); Willi, O.; Barringer, L.; Vickers, C. [Imperial College of Science, Technology and Medicine, London (United Kingdom)] [Imperial College of Science, Technology and Medicine, London (United Kingdom); Watt, R. [P24, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [P24, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Nazarov, W. [Chemistry Department, University of Dundee (United Kingdom)] [Chemistry Department, University of Dundee (United Kingdom)

1999-05-01T23:59:59.000Z

225

Interference in above-threshold-ionization electron distributions from molecules  

SciTech Connect

We present quantum-mechanical studies on above-threshold ionization of molecular ions in two and three dimensions. The momentum distributions show signatures of interfering emissions from the molecular centers. These structures deviate from a simple double-slit model that ignores the electron-ion interaction, but they are reproduced by an eikonal model. Such distortions of the interference pattern are partly responsible for the absence of clear interference patterns in the angle-integrated electron energy spectra.

Henkel, Jost [Institut fuer Physikalische und Theoretische Chemie, Universitaet Wuerzburg, and Roentgen Research Center for Complex Material Systems, Am Hubland, D-97074 Wuerzburg (Germany); Institut fuer Theoretische Physik and Centre for Quantum Engineering and Space-Time Research (QUEST), Leibniz Universitaet Hannover Appelstrasse 2, D-30167 Hannover (Germany); Lein, Manfred [Institut fuer Theoretische Physik and Centre for Quantum Engineering and Space-Time Research (QUEST), Leibniz Universitaet Hannover Appelstrasse 2, D-30167 Hannover (Germany); Engel, Volker [Institut fuer Physikalische und Theoretische Chemie, Universitaet Wuerzburg, and Roentgen Research Center for Complex Material Systems, Am Hubland, D-97074 Wuerzburg (Germany)

2011-05-15T23:59:59.000Z

226

Ionization and equation of state of dense xenon at high pressures and high temperatures  

Science Journals Connector (OSTI)

The ionization degree and equation of state of dense xenon plasma were calculated by using self-consistent fluid variational theory for temperature of 4–30kK and density of 0.01–8.5g?cm3. The dense fluid xenon will be ionized at high pressures and temperatures. The ionization energy of xenon will be lowered due to the interactions among all particles of Xe, Xe+, Xe2+, and e. The ionization degree is obtained from nonideal ionization equilibrium, taking into account the correlative contributions to the chemical potential which is determined self-consistently by the free energy function. The composition of xenon has been calculated with given densities and temperatures in the region of partial ionization. The calculated results show a pressure softening regime at the onset of ionization. Comparison is performed with available shock-wave experiments and other theoretical calculations.

Q. F. Chen, L. C. Cai, Y. J. Gu, and Y. Gu

2009-01-22T23:59:59.000Z

227

The multiphoton ionization of uranium hexafluoride. Revision 1  

SciTech Connect

Multiphoton ionization (MPI) time-of-flight mass spectroscopy and photoelectron spectroscopy studies of UF{sub 6} have been conducted using focused light from the Nd:YAG laser fundamental ({lambda}=1064 nm) and its harmonics ({lambda}=532, 355, or 266 nm), as well as other wavelengths provided by a tunable dye laser. The MPI mass spectra are dominated by the singly and multiply charged uranium ions rather than by the UF{sub x}{sup +} fragment ions even at the lowest laser power densities at which signal could be detected. The laser power dependence of U{sup n+} ions signals indicates that saturation can occur for many of the steps required for their ionization. In general, the doubly-charged uranium ion (U{sup 2+}) intensity is much greater than that of the singly-charged uranium ion (U{sup +}). For the case of the tunable dye laser experiments, the U{sup n+} (n = 1- 4) wavelength dependence is relatively unstructured and does not show observable resonance enhancement at known atomic uranium excitation wavelengths. The dominance of the U{sup 2+} ion and the absence or very small intensities of UF{sub x}{sup +} fragments, along with the unsaturated wavelength dependence, indicate that mechanisms may exist other than ionization of bare U atoms after the stepwise photodissociation of F atoms from the parent molecule.

Armstrong, D.P. [Oak Ridge K-25 Site, TN (United States). UEO Enrichment Technical Operations Div.] [Oak Ridge K-25 Site, TN (United States). UEO Enrichment Technical Operations Div.

1992-05-01T23:59:59.000Z

228

Ionized gas at the edge of the Central Molecular Zone  

E-Print Network (OSTI)

To determine the properties of the ionized gas at the edge of the CMZ near Sgr E we observed a small portion of the edge of the CMZ near Sgr E with spectrally resolved [C II] 158 micron and [N II] 205 micron fine structure lines at six positions with the GREAT instrument on SOFIA and in [C II] using Herschel HIFI on-the-fly strip maps. We use the [N II] spectra along with a radiative transfer model to calculate the electron density of the gas and the [C II] maps to illuminate the morphology of the ionized gas and model the column density of CO-dark H2. We detect two [C II] and [N II] velocity components, one along the line of sight to a CO molecular cloud at -207 km/s associated with Sgr E and the other at -174 km/s outside the edge of another CO cloud. From the [N II] emission we find that the average electron density is in the range of about 5 to 25 cm{-3} for these features. This electron density is much higher than that of the warm ionized medium in the disk. The column density of the CO-dark H$_2$ layer ...

Langer, W D; Pineda, J L; Velusamy, T; Requena-Torres, M A; Wiesemeyer, H

2015-01-01T23:59:59.000Z

229

Electron-impact ionization cross section of rubidium  

Science Journals Connector (OSTI)

A theoretical model for electron-impact ionization cross section has been applied to Rb and the theoretical cross section (from the threshold to 1 keV in incident energy) is in good agreement with the recent experimental data obtained using Rb atoms trapped in a magneto-optical trap. The theoretical model, called the binary-encounter–dipole (BED) model, combines a modified Mott cross section with the high-energy behavior of Born cross sections. To obtain the continuum dipole oscillator strength df/dE of the 5s electron required in the BED model, we used Dirac-Fock continuum wave functions with a core polarization potential that reproduced the known position of the Cooper minimum in the photoionization cross section. For inner-shell ionization, we used a simpler version of df/dE, which retained the hydrogenic shape. The contributions of the 4p?4d, 5s, and 5p autoionizing excitations were estimated using the plane-wave Born approximation. As a by-product, we also present the dipole oscillator strengths for the 5s?np1/2 and 5s?np3/2 transitions for high principal quantum numbers n near the ionization threshold obtained from the Dirac-Fock wave functions with the same core polarization potential as that used for the continuum wave functions.

Yong-Ki Kim; Jacek Migda?ek; Wojciech Siegel; Jacek Biero?

1998-01-01T23:59:59.000Z

230

Polarization operator approach to pair creation in short laser pulses  

E-Print Network (OSTI)

Short-pulse effects are investigated for the nonlinear Breit-Wheeler process, i.e. the production of an electron-positron pair induced by a gamma photon inside an intense plane-wave laser pulse. To obtain the total pair-creation probability we verify (to leading-order) the cutting rule for the polarization operator in the realm of strong-field QED by an explicit calculation. Using a double-integral representation for the leading-order contribution to the polarization operator, compact expressions for the total pair-creation probability inside an arbitrary plane-wave background field are derived. Correspondingly, the photon wave function including leading-order radiative corrections in the laser field is obtained via the Schwinger-Dyson equation in the quasistatic approximation. Moreover, the influence of the carrier-envelope phase and of the laser pulse shape on the total pair-creation probability in a linearly polarized laser pulse is investigated, and the validity of the (local) constant-crossed field approximation analyzed. It is shown that with presently available technology pair-creation probabilities of the order of ten percent could be reached for a single gamma photon.

Sebastian Meuren; Karen Z. Hatsagortsyan; Christoph H. Keitel; Antonino Di Piazza

2015-01-28T23:59:59.000Z

231

Exact eigenvalues of the pairing Hamiltonian using continuum level density  

Science Journals Connector (OSTI)

The pairing Hamiltonian constitutes an important approximation in many-body systems; it is exactly soluble and quantum integrable. On the other hand, the continuum single-particle level density (CSPLD) contains information about the continuum energy spectrum. The question of whether one can use the Hamiltonian with constant pairing strength for correlations in the continuum is still unanswered. In this paper we generalize the Richardson exact solution for the pairing Hamiltonian including correlations in the continuum. The resonant and nonresonant continua are included through the CSPLD. The resonant correlations are made explicit by using the Cauchy theorem. Low-lying states with seniority 0 and 2 are calculated for the even carbon isotopes. We conclude that energy levels can indeed be calculated with constant pairing in the continuum using the CSPLD. It is found that the nucleus 24C is unbound. The real and complex energy representations of the continuum is developed and their differences are shown. The trajectory of the pair energies in the continuum for the nucleus 28C is shown.

R. Id Betan

2012-06-07T23:59:59.000Z

232

Energy Efficiency and Fitness - A Complementary Pair | Department of  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Efficiency and Fitness - A Complementary Pair Efficiency and Fitness - A Complementary Pair Energy Efficiency and Fitness - A Complementary Pair June 23, 2011 - 4:15pm Addthis Erin R. Pierce Erin R. Pierce Digital Communications Specialist, Office of Public Affairs I recently read about a study on fidgeting or as researchers refer to it-incidental physical activity. The study shows that the small collection of movements we often find inconsequential-like drumming your fingers, tapping your foot, or running after the bus-have significant health and cardiovascular benefits. The more I thought about it the more I realized that many everyday activities that contribute to overall fitness turn out to be quite energy-efficient and environmentally friendly as well. Take my commute for instance-every weekday I cram my way into a crowded

233

Energy Efficiency and Fitness - A Complementary Pair | Department of  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Energy Efficiency and Fitness - A Complementary Pair Energy Efficiency and Fitness - A Complementary Pair Energy Efficiency and Fitness - A Complementary Pair June 23, 2011 - 4:15pm Addthis Erin R. Pierce Erin R. Pierce Digital Communications Specialist, Office of Public Affairs I recently read about a study on fidgeting or as researchers refer to it-incidental physical activity. The study shows that the small collection of movements we often find inconsequential-like drumming your fingers, tapping your foot, or running after the bus-have significant health and cardiovascular benefits. The more I thought about it the more I realized that many everyday activities that contribute to overall fitness turn out to be quite energy-efficient and environmentally friendly as well. Take my commute for instance-every weekday I cram my way into a crowded

234

Repulsive aspects of pairing correlation in nuclear fusion reaction  

E-Print Network (OSTI)

Numerical simulation on nuclear collisions are performed using the canonical-basis time-dependent Hartree-Fock-Bogoliubov theory (Cb-TDHFB) in the three-dimensional coordinate space. Comparing results of the Cb-TDHFB and the conventional time-dependent Hartree-Fock (TDHF) calculations, we study effects of the pairing correlation on fusion reaction of $^{22}$O+$^{22}$O, $^{52}$Ca+$^{52}$Ca, and $^{22}$O+$^{52}$Ca, using the Skyrme SkM$^*$ functional and a contact-type pairing energy functional. Although current results are yet preliminary, they may suggest that the pairing correlation could hinder the fusion probability at energies in the vicinity of the Coulomb barrier height. We also perform a calculation for heavier nuclei, $^{96}$Zn+$^{124}$Sn, which seems to suggest a similar hindrance effect.

Shuichiro Ebata; Takashi Nakatsukasa

2014-08-08T23:59:59.000Z

235

Repulsive aspects of pairing correlation in nuclear fusion reaction  

E-Print Network (OSTI)

Numerical simulation on nuclear collisions are performed using the canonical-basis time-dependent Hartree-Fock-Bogoliubov theory (Cb-TDHFB) in the three-dimensional coordinate space. Comparing results of the Cb-TDHFB and the conventional time-dependent Hartree-Fock (TDHF) calculations, we study effects of the pairing correlation on fusion reaction of $^{22}$O+$^{22}$O, $^{52}$Ca+$^{52}$Ca, and $^{22}$O+$^{52}$Ca, using the Skyrme SkM$^*$ functional and a contact-type pairing energy functional. Although current results are yet preliminary, they may suggest that the pairing correlation could hinder the fusion probability at energies in the vicinity of the Coulomb barrier height. We also perform a calculation for heavier nuclei, $^{96}$Zn+$^{124}$Sn, which seems to suggest a similar hindrance effect.

Ebata, Shuichiro

2014-01-01T23:59:59.000Z

236

Isovector pairing collective motion: Generator-coordinate-method approach  

Science Journals Connector (OSTI)

Isovector pairing collective motion is treated by means of the generator coordinate method. In this scheme, the isospin and number projection is performed analytically by the recognition of symmetry properties in the generalized Bardeen-Cooper-Schrieffer wave functions. Among the results obtained, our generator-coordinate-method values of energy and spectroscopic amplitude are shown to be comparable to those of shell model calculations. This is indeed encouraging, especially in view of the fact that they were reached using a simple approximation. The great simplicity of the present method, as compared with earlier complicated versions, suggests that they might prove useful in the study of isovector pairing collective states which are strongly populated by pair transfer reactions in medium weight nuclei.

Mauro Kyotoku and Hsi-Tseng Chen

1987-09-01T23:59:59.000Z

237

A pair of oscillators interacting with a common heat bath  

E-Print Network (OSTI)

Here the problem considered is that of a pair of oscillators coupled to a common heat bath. Many, if not most, discussions of a single operator coupled to a bath have used the independent oscillator model of the bath. However, that model has no notion of separation, so the question of phenomena when the oscillators are near one another compared with when they are widely separated cannot be addressed. Here the Lamb model of an oscillator attached to a stretched string is generalized to illustrate some of these questions. The coupled Langevin equations for a pair of oscillators attached to the string at different points are derived and their limits for large and small separations obtained. Finally, as an illustration of a different phenomenon, the fluctuation force between a pair of masses attached to the string is calculated, with closed form expressions for the force at small and large separations.

G. W. Ford; R. F. O'Connell

2014-08-25T23:59:59.000Z

238

The effect of intergalactic helium on hydrogen reionization: implications for the sources of ionizing photons at z>6  

Science Journals Connector (OSTI)

......model the effect of hydrogen and helium ionizing...for modelling the production of ionizing photons...the total comoving hydrogen ionizing emissivity...ionizing photon production increases toward...because almost all the methods used to derive are...patches of neutral hydrogen may still lurk undetected......

B. Ciardi; J. S. Bolton; A. Maselli; L. Graziani

2012-06-11T23:59:59.000Z

239

Locating–paired-dominating sets in square grids  

Science Journals Connector (OSTI)

Abstract A set S of vertices of a graph G is paired-dominating if S induces a matching in G and S dominates all vertices of G . A set S ? V ( G ) is locating if for any two distinct vertices u , v ? V ( G ) ? S , N ( u ) ? S ? N ( v ) ? S , where N ( u ) and N ( v ) are open neighborhoods of vertices u and v . We give a complete characterization of locating–paired-dominating sets with minimal density in the infinite square grid Z 2 .

?udovít Niepel

2014-01-01T23:59:59.000Z

240

Landau-Zener Transitions in Frozen Pairs of Rydberg Atoms  

SciTech Connect

We have induced adiabatic transitions in pairs of frozen Rydberg sodium atoms of a supersonic beam. The diatomic ns+ns{yields}np+(n-1)p transition takes place in a time-dependent electric field and originates from the adiabatic change of the internal state of the pair induced by the dipole-dipole interaction. This is experimentally achieved by sweeping an electric field across the energy degeneracy ns ns-np(n-1)p. Our results fully agree with a two-level Landau-Zener model in the diatom system.

Saquet, Nicolas; Cournol, Anne; Beugnon, Jerome; Robert, Jacques; Pillet, Pierre; Vanhaecke, Nicolas [Laboratoire Aime Cotton, CNRS, Batiment 505, Universite Paris-Sud, 91405 Orsay (France)

2010-04-02T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

Muon Bremsstrahlung and Muonic Pair Production in Air Showers  

E-Print Network (OSTI)

The objective of this work is to report on the modifications in air shower development due to muon bremsstrahlung and muonic pair production. In order to do that we have implemented new muon bremsstrahlung and muonic pair production procedures in the AIRES air shower simulation system, and have used it to simulate ultra high energy showers in different conditions. The influence of the mentioned processes in the global development of the air shower is important for primary particles of large zenith angles, while they do not introduce significant changes in the position of the shower maximum.

A. Cillis; S. J. Sciutto

2000-06-08T23:59:59.000Z

242

The effect of dimensional preference on paired-associate learning  

E-Print Network (OSTI)

THE EFFECT OF DIMENSIONAL PREFERENCE ON PAIRED-ASSOCIATE LEARNING A Th sis by DAYID HENRY GILL Submitted to the Graduate Co'liege of Texas AIM University in partial fulfillment of the requirement for the degree of MA TER OF SCIENCE August... 1970 Major Subject: Psychology THE EFFECT OF DIMENSIONAL PREFERENCE ON PAIRED-ASSOCIATE LEARNING A Thesis by DAVID HENRY GILL Approved as to style and content by: Chairman o Committee a Lo Member) of o pe t~ent Member August 1970 ADSTRACT...

Gill, David Henry

1970-01-01T23:59:59.000Z

243

Thermal tunneling of qq¯ pairs in A-A collisions  

Science Journals Connector (OSTI)

Consideration of various time scales in A-A collisions suggests that it is relevant to determine qq¯ pair production rate at finite temperature. We have evaluated this rate using standard techniques of finite temperature field theory. At high temperature the rate is proportional to T2 and has a value higher than the rate at T=0. It is also observed that the rate of pair production decreases as one moves away from the Lorentz contracted nuclei, towards the center in the c.m. coordinate system.

Avijit K. Ganguly; Predhiman K. Kaw; Jitendra C. Parikh

1995-04-01T23:59:59.000Z

244

Cylindrically confined pair-ion-electron and pair-ion plasmas having axial sheared flow and radial gradients  

SciTech Connect

The linear and nonlinear dynamics of pair-ion (PI) and pair-ion-electron plasmas (PIE) have been investigated in a cylindrical geometry with a sheared plasma flow along the axial direction having radial dependence. The coupled linear dispersion relation of low frequency electrostatic waves has been presented taking into account the Guassian profile of density and linear gradient of sheared flow. It is pointed out that the quasi-neutral cold inhomogeneous pure pair ion plasma supports only the obliquely propagating convective cell mode. The linear dispersion relation of this mode has been solved using boundary conditions. The nonlinear structures in the form of vortices formed by different waves have been discussed in PI and PIE plasmas.

Batool, Nazia; Saleem, H. [National Centre for Physics (NCP), Quaid-i-Azam University Campus, Islamabad (Pakistan)] [National Centre for Physics (NCP), Quaid-i-Azam University Campus, Islamabad (Pakistan)

2013-10-15T23:59:59.000Z

245

First Energy and Angle differential Measurements of e^+e^- -pairs emitted by Internal Pair Conversion of excited Heavy Nuclei  

E-Print Network (OSTI)

We present the first energy and angle resolved measurements of e+e- pairs emitted from heavy nuclei (Z>=40) at rest by internal pair conversion (IPC) of transitions with energies of less than 2MeV as well as recent theoretical results using the DWBA method, which takes full account of relativistic effects, magnetic substates and finite size of the nucleus. The 1.76MeV E0 transition in Zr90 (Sr source) and the 1.77MeV M1 transition in Pb207 (Bi source) have been investigated experimentally using the essentially improved set-up at the double-ORANGE beta-spectrometer of GSI. The measurements prove the capability of the setup to cleanly identify the IPC pairs in the presence of five orders of magnitude higher beta- and gamma background from the same source and to yield essentially background-free sum spectra despite the large background. Using the ability of the ORANGE setup to directly determine the opening angle of the e+e- pairs, the angular correlation of the emitted pairs was measured. In the Zr90 case the correlation could be deduced for a wide range of energy differences of the pairs. The Zr90 results are in good agreement with recent theory. The angular correlation deduced for the M1 transition in Pb207 is in strong disagreement with theoretical predictions derived within the Born approximation and shows almost isotropic character. This is again in agreement with the new theoretical results.

U. Leinberger; E. Berdermann; F. Heine; S. Heinz; O. Joeres; P. Kienle; I. Koenig; W. Koenig; C. Kozhuharov; A. Schroeter; H. Tsertos; C. Hofmann; G. Soff

1997-04-18T23:59:59.000Z

246

Radiative proton-antiproton annihilation to a lepton pair  

SciTech Connect

The annihilation of proton and antiproton to an electron-positron pair, including radiative corrections due to the emission of virtual and real photons is considered. The results are generalized to leading and next-to leading approximations. The relevant distributions are derived and numerical applications are given in the kinematical range accessible to the PANDA experiment at the FAIR facility.

Ahmadov, A. I. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Institute of Physics, Azerbaijan National Academy of Sciences, Baku (Azerbaijan); Bytev, V. V.; Kuraev, E. A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Tomasi-Gustafsson, E. [CEA, IRFU, SPhN, Saclay, 91191 Gif-sur-Yvette Cedex, France, and CNRS/IN2P3, Institut de Physique Nucleaire, UMR 8608, 91405 Orsay (France)

2010-11-01T23:59:59.000Z

247

OD3P: On-Demand Page Paired PCM  

Science Journals Connector (OSTI)

With current memory scalability challenges, Phase Change Memory (PCM) is viewed as an attractive replacement to DRAM. The preliminary concern for PCM applicability is its limited write endurance that is highly affected by process variation in nanometer ... Keywords: Lifetime, Page Pairing

Marjan Asadinia, Mohammad Arjomand, Hamid Sarbazi-Azad

2014-06-01T23:59:59.000Z

248

Chimeric transcript discovery by paired-end transcriptome sequencing  

Science Journals Connector (OSTI)

...Strategy Against Existing Single Read Approaches. To assess the merit of adopting a paired-end transcriptome approach, we compared...prepared using QiagenTips-100 (Qiagen). DNA was labeled by nick translation labeling with biotin-16-dUTP and digoxigenin-11-dUTP...

Christopher A. Maher; Nallasivam Palanisamy; John C. Brenner; Xuhong Cao; Shanker Kalyana-Sundaram; Shujun Luo; Irina Khrebtukova; Terrence R. Barrette; Catherine Grasso; Jindan Yu; Robert J. Lonigro; Gary Schroth; Chandan Kumar-Sinha; Arul M. Chinnaiyan

2009-01-01T23:59:59.000Z

249

Creation and pinning of vortex-antivortex pairs  

E-Print Network (OSTI)

Computer modeling is reported about the creation and pinning of a magnetic vortex-antivortex (V-AV) pair in a superconducting thin film, due to the magnetic field of a vertical magnetic dipole above the film, and two antidot pins inside the film...

Kim, Sangbum; Hu, Chia-Ren; Andrews, Malcolm J.

2006-01-01T23:59:59.000Z

250

Magnetic Pair Creation Transparency in Gamma-Ray Pulsars  

E-Print Network (OSTI)

Magnetic pair creation $\\gamma \\to e^+e^-$ has been at the core of radio pulsar paradigms and central to polar cap models of gamma-ray pulsars for over three decades. The Fermi gamma-ray pulsar population now exceeds 140 sources and has defined an important part of Fermi's science legacy. Among the population characteristics well established is the common occurrence of exponential turnovers in their spectra in the 1--10 GeV range. These turnovers are too gradual to arise from magnetic pair creation in the strong magnetic fields of pulsar inner magnetospheres. By demanding insignificant photon attenuation precipitated by such single-photon pair creation, the energies of these turnovers for Fermi pulsars can be used to compute lower bounds for the typical altitude of GeV band emission. This paper explores such pair transparency constraints below the turnover energy, and updates earlier altitude bound determinations of that have been deployed in various Fermi pulsar papers. For low altitude emission locales, gen...

Story, Sarah A

2014-01-01T23:59:59.000Z

251

ENERGY LEVEL SPECTROSCOPY OF A BOUND VORTEX-ANTIVORTEX PAIR  

E-Print Network (OSTI)

vortex- antivortex (VAV) state in an annular Josephson junction. The bound VAV pair is formed microwave spectroscopy. Keywords: Macroscopic quantum effects, long Josephson junctions, vortex­9]. Most of the studied systems, such as dc-biased Josephson junctions (JJ), supercon- ducting quantum

Wallraff, Andreas

252

The environment of low-redshift quasar pairs  

Science Journals Connector (OSTI)

......2014 research-article Article The environment of low-redshift quasar pairs A. Sandrinelli...investigate the properties of the galaxy environment of a sample of 14 low-redshift (z...separation does not require any extraordinary environment. galaxies: clusters: general|quasars......

A. Sandrinelli; R. Falomo; A. Treves; E. P. Farina; M. Uslenghi

2014-01-01T23:59:59.000Z

253

Laboratory Study of Hall Reconnection in Partially Ionized Plasmas  

SciTech Connect

The effects of partial ionization (ni/nn ? 1%) on magnetic reconnection in the Hall regime have been studied systematically in the Magnetic Reconnection Experiment (MRX). It is shown that, when neutrals are added the Hall quadrupole field pattern and thus electron flow is unchanged while the ion outflow speed is reduced due to ion-neutral drag. However, in constrast to theoretical predictions, the ion diffusion layer width does not change appreciably. Therefore, the total ion outflow flux and the normalized reconnection rate are reduced.

Eric E. Lawrence, Hanto Ji, Masaaki Yamaada and Jongsoo Yoo

2012-05-15T23:59:59.000Z

254

Photo-ionization and residual electron effects in guided streamers  

SciTech Connect

Complementary experiments and numerical modeling reveal the important role of photo-ionization in the guided streamer propagation in helium-air gas mixtures. It is shown that the minimum electron concentration ?10{sup 8?}cm{sup ?3} is required for the regular, repeated propagation of the plasma bullets, while the streamers propagate in the stochastic mode below this threshold. The stochastic-to-regular mode transition is related to the higher background electron density in front of the propagating streamers. These findings help improving control of guided streamer propagation in applications from health care to nanotechnology and improve understanding of generic pre-breakdown phenomena.

Wu, S.; Lu, X., E-mail: luxinpei@hotmail.com; Liu, D.; Yang, Y.; Pan, Y. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Ostrikov, K. [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4000 (Australia); Commonwealth Scientific and Industrial Research Organization, P. O. Box 218, Lindfield, NSW 2070 (Australia); School of Physics, The University of Sydney, Sydney NSW 2006 (Australia)

2014-10-15T23:59:59.000Z

255

Depolarizing collisions with hydrogen: neutral and singly ionized alkaline earths  

E-Print Network (OSTI)

Depolarizing collisions are elastic or quasielastic collisions that equalize the populations and destroy the coherence between the magnetic sublevels of atomic levels. In astrophysical plasmas, the main depolarizing collider is neutral hydrogen. We consider depolarizing rates on the lowest levels of neutral and singly ionized alkaly-earths Mg I, Sr I, Ba I, Mg II, Ca II, and Ba II, due to collisions with H. We compute ab initio potential curves of the atom-H system and solve the quantum mechanical dynamics. From the scattering amplitudes we calculate the depolarizing rates for Maxwellian distributions of colliders at temperatures T atmosphere, and their effect on Hanle effect diagnostics of solar magnetic fields.

Sainz, Rafael Manso; Sanz-Sanz, Cristina; Aguado, Alfredo; Ramos, Andres Asensio; Bueno, Javier Trujillo

2014-01-01T23:59:59.000Z

256

Photo-Ionization of Lithium: A Many-Body Calculation  

Science Journals Connector (OSTI)

The photo-ionization cross section a? of lithium has been calculated to second order in Brueckner-Goldstone perturbation theory with Hartree-Fock as zero order, for ejected electron energies in the range 0<~k2<~0. 36 Ry. Other Hartree-Fock calculations of a? are analyzed using certain new theorems relating alternative forms of the matrix element. The final second-order perturbed values of a? in the length and velocity formulations are in good agreement with experiment throughout the energy range studied.

Edward S. Chang and M. R. C. McDowell

1968-12-05T23:59:59.000Z

257

Stability of negative ionization fronts: Regularization by electric screening?  

Science Journals Connector (OSTI)

We recently have proposed that a reduced interfacial model for streamer propagation is able to explain spontaneous branching. Such models require regularization. In the present paper we investigate how transversal Fourier modes of a planar ionization front are regularized by the electric screening length. For a fixed value of the electric field ahead of the front we calculate the dispersion relation numerically. These results guide the derivation of analytical asymptotes for arbitrary fields: for small wave-vector k, the growth rate s(k) grows linearly with k, for large k, it saturates at some positive plateau value. We give a physical interpretation of these results.

Manuel Arrayás and Ute Ebert

2004-03-31T23:59:59.000Z

258

Optical remote diagnostics of atmospheric propagating beams of ionizing radiation  

DOE Patents (OSTI)

Data is obtained for use in diagnosing the characteristics of a beam of ionizing radiation, such as charged particle beams, neutral particle beams, and gamma ray beams. In one embodiment the beam is emitted through the atmosphere and produces nitrogen fluorescence during passage through air. The nitrogen fluorescence is detected along the beam path to provide an intensity from which various beam characteristics can be calculated from known tabulations. Optical detecting equipment is preferably located orthogonal to the beam path at a distance effective to include the entire beam path in the equipment field of view.

Karl, Jr., Robert R. (Los Alamos, NM)

1990-01-01T23:59:59.000Z

259

Breakdown of the Dipole Approximation in Strong-Field Ionization  

E-Print Network (OSTI)

We report the breakdown of the electric dipole approximation in the long-wavelength limit in strong-field ionization with linearly polarized few-cycle mid-infrared laser pulses at intensities on the order of 10$^{13}$ W/cm$^2$. Photoelectron momentum distributions were recorded by velocity map imaging and projected onto the beam propagation axis. We observe an increasing shift of the peak of this projection opposite to the beam propagation direction with increasing laser intensities. From a comparison with semi-classical simulations, we identify the combined action of the magnetic field of the laser pulse and the Coulomb potential as origin of our observations.

Ludwig, A; Mayer, B W; Phillips, C R; Gallmann, L; Keller, U

2014-01-01T23:59:59.000Z

260

Breakdown of the Dipole Approximation in Strong-Field Ionization  

E-Print Network (OSTI)

We report the breakdown of the electric dipole approximation in the long-wavelength limit in strong-field ionization with linearly polarized few-cycle mid-infrared laser pulses at intensities on the order of 10$^{13}$ W/cm$^2$. Photoelectron momentum distributions were recorded by velocity map imaging and projected onto the beam propagation axis. We observe an increasing shift of the peak of this projection opposite to the beam propagation direction with increasing laser intensities. From a comparison with semi-classical simulations, we identify the combined action of the magnetic field of the laser pulse and the Coulomb potential as origin of our observations.

A. Ludwig; J. Maurer; B. W. Mayer; C. R. Phillips; L. Gallmann; U. Keller

2014-08-11T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

Metabolic Differences in Microbial Cell Populations Revealed by Nanophotonic Ionization  

SciTech Connect

ellular differences are linked to cell differentiation, the proliferation of cancer and to the development of drug resistance in microbial infections. Due to sensitivity limitations, however, large- scale metabolic analysis at the single cell level is only available for cells significantly larger in volume than Saccharomyces cerevisiae (~30 fL). Here we demonstrate that by a nanophotonic ionization platform and mass spectrometry, over one hundred up to 108 metabolites, or up to 18% of the known S. cerevisiae metabolome, can be identified in very small cell populations (n < 100). Under ideal conditions, r Relative quantitation of up to 4% of the metabolites is achieved at the single cell level.

Walker, Bennett [George Washington University] [George Washington University; Antonakos, Cory [George Washington University] [George Washington University; Retterer, Scott T [ORNL] [ORNL; Vertes, Akos [George Washington University] [George Washington University

2013-01-01T23:59:59.000Z

262

Miniature quadrupole mass spectrometer having a cold cathode ionization source  

DOE Patents (OSTI)

An improved quadrupole mass spectrometer is described. The improvement lies in the substitution of the conventional hot filament electron source with a cold cathode field emitter array which in turn allows operating a small QMS at much high internal pressures then are currently achievable. By eliminating of the hot filament such problems as thermally "cracking" delicate analyte molecules, outgassing a "hot" filament, high power requirements, filament contamination by outgas species, and spurious em fields are avoid all together. In addition, the ability of produce FEAs using well-known and well developed photolithographic techniques, permits building a QMS having multiple redundancies of the ionization source at very low additional cost.

Felter, Thomas E. (Livermore, CA)

2002-01-01T23:59:59.000Z

263

Vector- and Scalar-Bilepton Pair Production in Hadron Colliders  

E-Print Network (OSTI)

We study the double-charged vector-bilepton pair production and double-charged scalar-bilepton pair production {\\it via} $p + p \\longrightarrow Y^{++} + Y^{--} + X$ and $p + p \\longrightarrow S_1^{++} + S_1^{--} + X$, where $Y$ and $S_1$ are vector and scalar bileptons respectively, in the framework of the minimal version of the 3-3-1 model. We compute the photon, $Z$, and $Z^\\prime$ s-channel contributions for the elementary process of bilepton scalar pair production, and to keep the correct unitarity behavior for the elementary $q \\bar q$ interaction, we include the exotic quark t-channel contribution in the vector-bilepton pair production calculation. We explore a mass range for $Z^\\prime$ and we fix the exotic quark mass within the experimental bounds. In this model, the vector-bilepton mass is directly related to $M_{Z^\\prime}$ and we consider scalar mass values around the vector-bilepton mass. We show that the total cross section for vector-bilepton production is 3 orders of magnitude larger than for scalar pair production for $\\sqrt s= 7$ TeV and 14 TeV and we obtain the number of events for the proposed LHC luminosities as a function of the bilepton mass. In addition we present some invariant mass and transverse momentum distributions. When comparing these distributions we observe quite different behavior providing the determination of the bilepton nature. We conclude that one can disentangle the production rates and that the LHC can be capable of detecting these predicted particles as a signal for new physics.

E. Ramirez Barreto; Y. A. Coutinho; J. Sá Borges

2011-03-07T23:59:59.000Z

264

THE PAIR FRACTION OF MASSIVE GALAXIES AT 0 {<=} z {<=} 3  

SciTech Connect

Using a mass-selected (M{sub *} {>=} 10{sup 11} M{sub Sun }) sample of 198 galaxies at 0 {<=} z {<=} 3.0 with Hubble Space Telescope/NICMOS H{sub 160}-band images from the COSMOS survey, we find evidence for the evolution of the pair fraction above z {approx} 2, an epoch in which massive galaxies are believed to undergo significant structural and mass evolution. We observe that the pair fraction of massive galaxies is 0.15 {+-} 0.08 at 1.7 {<=}z {<=} 3.0, where galaxy pairs are defined as massive galaxies having a companion of flux ratio from 1:1 to 1:4 within a projected separation of 30 kpc. This is slightly lower but still consistent with the pair fraction measured previously in other studies, and the merger fraction predicted in halo-occupation modeling. The redshift evolution of the pair fraction is described by a power law F(z) = (0.07 {+-} 0.04) Multiplication-Sign (1 + z){sup 0.6{+-}0.5}. The merger rate is consistent with no redshift evolution; however it is difficult to constrain due to the limited sample size and the high uncertainties in the merging timescale. Based on the merger rate calculation, we estimate that a massive galaxy undergoes on average 1.1 {+-} 0.5 major mergers from z = 3 to 0. The observed merger fraction is sufficient to explain the number density evolution of massive galaxies, but insufficient to explain the size evolution. This is a hint that mechanism(s) other than major merging may be required to increase the sizes of the massive, compact quiescent galaxies from z {approx} 2 to 0.

Man, Allison W. S.; Toft, Sune; Zirm, Andrew W. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen (Denmark); Wuyts, Stijn [Max-Planck-Institut fuer Extraterrestrische Physik, Garching bei Muenchen (Germany); Van der Wel, Arjen, E-mail: allison@dark-cosmology.dk, E-mail: sune@dark-cosmology.dk, E-mail: azirm@dark-cosmology.dk, E-mail: swuyts@mpe.mpg.de, E-mail: vdwel@mpia.de [Max-Planck-Institut fuer Astronomie, Heidelberg (Germany)

2012-01-10T23:59:59.000Z

265

Interactive visual intervention planning in particle accelerator environments with ionizing radiation  

E-Print Network (OSTI)

Radiation is omnipresent. It has many interesting applications: in medicine, where it allows curing and diagnosing patients; in communication, where modern communication systems make use of electromagnetic radiation; and in science, where it is used to discover the structure of materials; to name a few. Physically, radiation is a process in which particles or waves travel through any kind of material, usually air. Radiation can be very energetic, in which case it can break the atoms of ordinary matter (ionization). If this is the case, radiation is called ionizing. It is known that ionizing radiation can be far more harmful to living beings than non-ionizing radiation. In this dissertation, we are concerned with ionizing radiation. Naturally occurring ionizing radiation in the form of radioactivity is a most natural phenomenon. Almost everything is radioactive: there is radiation emerging from the soil, it is in the air, and the whole planet is constantly undergoing streams of energetic cosmic radiation. Sinc...

Fabry, Thomas

266

The Influence of Chemi-ionization and Recombination Processes on Spectral Line Shapes in Stellar Atmospheres  

E-Print Network (OSTI)

In this work, the chemi-ionization processes in atom- Rydberg atom collisions, as well as the corresponding chemi-recombination processes are considered as factors of influence on the atom exited-state populations in weakly ionized layers of stellar atmospheres. The presented results are related to the photospheres of the Sun and some M red dwarfs as well as weakly ionized layers of DB white dwarfs atmospheres. It has been found that the mentioned chemi ionization/recombination processes dominate over the relevant concurrent electron-atom and electron-ion ionization and recombination process in all parts of considered stellar atmospheres. The obtained results demonstrate the fact that the considered chemi ionization/recombination processes must have a very significant influence on the optical properties of the stellar atmospheres. Thus, it is shown that these processes and their importance for non-local thermodynamic equilibrium (non-LTE) modeling of the solar atmospheres should be investigated further.

Mihajlov, Anatolij A; Sreckovic, Vladimir A; Dimitrijevic, Milan S

2011-01-01T23:59:59.000Z

267

High efficiency resonance ionization mass spectrometric analysis by external laser cavity enhancement techniques  

SciTech Connect

The demand to measure high dynamic range isotope ratios on small samples with resonance ionization mass spectrometry (RIMS) continues to increase. This paper discusses high ionization efficiency methods which can be applied to continuous wave (cw) RIMS to potentially achieve several tens of percent ionization efficiencies for certain elements. The primary technique under development to achieve this is an external laser cavity which can generate very high circulating laser powers. 12 refs., 3 figs.

Johnson, S.G.; Rios, E.L.; Miller, C.M.; Fearey, B.L.

1991-01-01T23:59:59.000Z

268

Energy loss of nuclear fragments in partially ionized materials of high atomic number  

Science Journals Connector (OSTI)

Methods used for the computation of the stopping power of high-atomic-number media to light and heavy nuclear fragments in un-ionized and completely ionized states are reasonably well developed. This is not the case for partially ionized states. We propose a method that bridges these two extremes and discuss applications of the method to ? particles and fission fragments in uranium at extreme temperatures and densities.

R. A. Lewis; G. A. Smith; W. S. Toothacker

1991-07-01T23:59:59.000Z

269

Laser ablation electrospray ionization (LAESI) for atmospheric pressure, In vivo, and imaging 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 (LA) with electrospray ionization (ESI).

Vertes, Akos (Reston, VA); Nemes, Peter (Silver Spring, MD)

2011-11-29T23:59:59.000Z

270

Laser ablation electrospray ionization (LAESI) for atmospheric pressure, in vivo, and imaging 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

2014-08-19T23:59:59.000Z

271

Laser ablation electrospray ionization (LAESI) for atmospheric pressure, in vivo, and imaging 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

272

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

273

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

274

A Comparison of 400nm and 800nm Femtosecond Laser Pulses in Dissociative Ionization of Ethanol  

Science Journals Connector (OSTI)

Role of the center wavelength of excitation laser pulses on dissociative ionization of ethanol is studied using 400 nm and 800 nm femtosecond laser pulses. Contribution of...

Shioyama, Tadamasa; Yazawa, Hiroki; Kannari, Fumihiko; Itakura, Ryuji; Yamanouchi, Kaoru

275

E-Print Network 3.0 - area position-sensitive ionization Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

coefficient of positional... photoelectron focusing and high electron transmission efficiency from the gas ionization area to the detector... their spectral resolution and...

276

Particle Velocity Distributions and Ionization Processes in a Gas-Puff Z Pinch  

Science Journals Connector (OSTI)

We have measured the time-dependent radial velocity distributions of singly to five times ionized ions in an imploding plasma shell by observing the spectral shapes and intensities of emission lines in various directions. An ionization wave propagating much faster than the local radial ion velocities is observed. The ionization front velocity is found to be consistent with estimates of electron heat conduction into the plasma-neutral layer. The ionization and velocity histories of the particles are experimentally determined. The mechanisms of momentum transfer to the particles are also determined and compared with existing models.

M. E. Foord; Y. Maron; G. Davara; L. Gregorian; A. Fisher

1994-06-13T23:59:59.000Z

277

Atmospheric Pressure Weakly Ionized Plasma Reactor Based on the Corona Discharge .  

E-Print Network (OSTI)

??Atmospheric pressure weakly ionized plasma (APWIP) is being used to treat or process goods and materials because it only activates the surface without modification of… (more)

[No author

2012-01-01T23:59:59.000Z

278

Strong-field high-frequency approximation to the multiphoton ionization of hydrogen  

Science Journals Connector (OSTI)

The strong-field multiphoton ionization of atoms is considered and a theoretical approach dealing nonperturbatively with the radiation field formulated. The general computational...

Trombetta, F; Basile, S; Ferrante, G

1990-01-01T23:59:59.000Z

279

Detection of methoxylated anions of fullerenes by electrospray ionization mass spectrometry  

SciTech Connect

Electrospray ionization mass spectrometry (ESI-MS) has been applied to the study of the reactions of fullerenes in solution. The C[sub 60][sup [minus

Wilson, S.R.; Wu, Y. (New York Univ., NY (United States))

1993-11-03T23:59:59.000Z

280

The effect of photo-ionization on the cooling rates of enriched, astrophysical plasmas  

E-Print Network (OSTI)

Radiative cooling is central to a wide range of astrophysical problems. Despite its importance, cooling rates are generally computed using very restrictive assumptions, such as collisional ionization equilibrium and solar relative abundances. We simultaneously relax both assumptions and investigate the effects of photo-ionization of heavy elements by the meta-galactic UV/X-ray background and of variations in relative abundances on the cooling rates of optically thin gas in ionization equilibrium. We find that photo-ionization by the meta-galactic background radiation reduces the net cooling rates by up to an order of magnitude for gas densities and temperatures typical of the shock-heated intergalactic medium and proto-galaxies. In addition, photo-ionization changes the relative contributions of different elements to the cooling rates. We conclude that photo-ionization by the ionizing background and heavy elements both need to be taken into account in order for the cooling rates to be correct to order of magnitude. Moreover, if the rates need to be known to better than a factor of a few, then departures of the relative abundances from solar need to be taken into account. We propose a method to compute cooling rates on an element-by-element basis by interpolating pre-computed tables that take photo-ionization into account. We provide such tables for a popular model of the evolving UV/X-ray background radiation, computed using the photo-ionization package CLOUDY.

Robert P. C. Wiersma; Joop Schaye; Britton D. Smith

2008-07-23T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

HCI Adsorption and Ionization on Amorphous and Crystalline H2O...  

NLE Websites -- All DOE Office Websites (Extended Search)

65, 2014041 using synchrotron-based electron spectroscopy Citation: Ayotte P, P Marchand, JL Daschbach, RS Smith, and BD Kay.2011."HCI Adsorption and Ionization on Amorphous...

282

Theory of steady-state plane tunneling-assisted impact ionization waves  

SciTech Connect

The effect of band-to-band and trap-assisted tunneling on the properties of steady-state plane ionization waves in p{sup +}-n-n{sup +} structures is theoretically analyzed. It is shown that such tunneling-assisted impact ionization waves do not differ in a qualitative sense from ordinary impact ionization waves propagating due to the avalanche multiplication of uniformly distributed seed electrons and holes. The quantitative differences of tunneling-assisted impact ionization waves from impact ionization waves are reduced to a slightly different relation between the wave velocity u and the maximum field strength E{sub M} at the front. It is shown that disregarding impact ionization does not exclude the possibility of the existence of tunneling-assisted ionization waves; however, their structure radically changes, and their velocity strongly decreases for the same E{sub M}. A comparison of the dependences u(E{sub M}) for various ionization-wave types makes it possible to determine the conditions under which one of them is dominant. In conclusion, unresolved problems concerning the theory of tunneling-assisted impact ionization waves are discussed and the directions of further studies are outlined.

Kyuregyan, A. S., E-mail: ask@vei.ru [Lenin All-Russian Electrical-Engineering Institute (Russian Federation)

2013-07-15T23:59:59.000Z

283

New developments in biochemical mass spectrometry: Electrospray ionization  

SciTech Connect

The principles, development, and recent application of electrospray ionization-mass spectrometry (ESI-MS) to biological compounds are reviewed. ESI-MS methods now allow determination of accurate molecular weights for proteins extending to over 50,000, and in some cases well over 100,000. Similar capabilities are being developed for oligonucleotides. The instrumentation used for ESI-MS is briefly described and it is shown that, although ionization efficiency appears to be uniformly high, detector sensitivity may be directly correlated with molecular weight. The use of tandem mass spectrometry (e.g., MS/MS) for extending collision-induced dissociation (CID) methods to the structural studies of large molecules is described. For example, effective CID of various albumin species (molecular weight {approximately}66,000) can be obtained, far larger than obtainable for singly charged molecular ions. The combination of capillary electrophoresis, in both free solution zone electrophoresis and isotachophoresis formats, as well as microcolumn liquid chromatography with ESI-MS, provides the capability for on-line separation and analysis of subpicomole quantities of proteins. These and other new developments related to ESI-MS are illustrated by a range of examples. Fundamental considerations suggest even more impressive developments may be anticipated related to detection sensitivity and methods for obtaining structural information.

Smith, R.D.; Loo, J.A.; Edmonds, C.G.; Barinaga, C.J.; Udseth, H.R. (Pacific Northwest Laboratory, Richland, WA (USA))

1990-05-01T23:59:59.000Z

284

Dynamics of short-pulse excitation, ionization and harmonic conversion  

SciTech Connect

In this paper we discuss recent calculations for xenon in pulsed laser fields which illustrate the multiphoton processes. In these calculations we have employed a single-active-electron (SAE) model which explicitly follows the separate time evolution of each of the valence electrons in the frozen, mean-field of the remaining, unexcited electrons, the nucleus and the laser field. This model works well for the rare gas atoms, at least partially because the neglected double or higher excitations involve states well above the ionization threshold. In the next section we give a brief description of the SAE model, emphasizing in particular the development of ion-core specific effective potentials. We present ionization, photoelectron and photoemission rates for xenon at 1.06 {mu}m and compare them to recent experimental results in the third section. We show that harmonics and ATI although related are not identical. The electron energy distributions do not show the cutoff observed in harmonics. After describing the quantum mechanical results and comparing them to recent experiments, we will present a simple two-step, quasi-classical model which explains these differences and which gives a more complete understanding of the dynamics of non-perturbative excitation.

Kulander, K.C.; Schafer, K.J.; Krause, J.L.

1993-01-01T23:59:59.000Z

285

Collision dynamics of proton with formaldehyde: Fragmentation and ionization  

SciTech Connect

Using time-dependent density functional theory, applied to the valence electrons and coupled non-adiabatically to molecular dynamics of the ions, we study the ionization and fragmentation of formaldehyde in collision with a proton. Four different impact energies: 35 eV, 85 eV, 135 eV, and 300 eV are chosen in order to study the energy effect in the low energy region, and ten different incident orientations at 85 eV are considered for investigating the steric effect. Fragmentation ratios, single, double, and total electron ionization cross sections are calculated. For large impact parameters, these results are close to zero irrespective of the incident orientations due to a weak projectile-target interaction. For small impact parameters, the results strongly depend on the collision energy and orientation. We also give the kinetic energy releases and scattering angles of protons, as well as the cross section of different ion fragments and the corresponding reaction channels.

Wang, Jing; Gao, Cong-Zhang [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China) [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Calvayrac, Florent [Institut des Molecules et Matériaux du Mans UMR 6283, Université du Maine, LUNAM 72085 Le Mans Cedex 9 (France)] [Institut des Molecules et Matériaux du Mans UMR 6283, Université du Maine, LUNAM 72085 Le Mans Cedex 9 (France); Zhang, Feng-Shou, E-mail: fszhang@bnu.edu.cn [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China) [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000 (China)

2014-03-28T23:59:59.000Z

286

Vacancy–group-V-impurity atom pairs in Ge crystals doped with P, As, Sb, and Bi  

Science Journals Connector (OSTI)

The electronic properties and thermal stability of centers incorporating a vacancy and a group-V-impurity atom (P, As, Sb, or Bi) in Ge crystals have been investigated. The vacancy-group-V-impurity atom pairs (E centers) have been induced by irradiation with Co60 ? rays and studied by means of capacitance transient techniques with the use of Au-Ge Schottky barriers. It is argued that the E centers in Ge have three charge states: double negative, single negative and neutral, and introduce two energy levels into the gap. There are pronounced changes in the activation energies of charge carrier emission for the particular states with the changes in the type of impurity atoms. The emission of an electron from the doubly negatively charged state of the centers is accompanied by a large change in entropy (?S), so, the free energy of the electron ionization, ?G(????)=?H(????)?T?S(????), changes significantly with temperature. Consequently, the position of the second acceptor level of the E centers {E(????)=Ec??G(????)} is temperature dependent. In Ge crystals having shallow donor concentrations in the range 1013–1015cm?3 at equilibrium conditions half-occupancy of the doubly negatively charged state of the vacancy-group-V-impurity atom pairs occurs when the Fermi level is at Ec?(0.18–0.22)eV. Changes in the entropy of ionization and the energy of electron emission for the double negative state of the E centers follow the Meyer-Neldel rule. It has been shown that the directly measured capture cross sections of electrons at the singly negatively charged E centers are temperature dependent and can be described by the multiphonon-assisted capture model. The first acceptor level of the E centers is in the lower part of the band gap. The formation of one vacancy–group-V-impurity atom complex results in the removal of at least two electrons from the conduction band in n-type Ge. It is thought that the E centers are responsible for the fast free carrier removal and n?p conversion of the conductivity type in oxygen-lean Ge crystals upon electron- or ?-irradiation at room temperature. The thermal stability of the E centers in Ge has been found to increase with an increase in the size of donor atoms.

V. P. Markevich; I. D. Hawkins; A. R. Peaker; K. V. Emtsev; V. V. Emtsev; V. V. Litvinov; L. I. Murin; L. Dobaczewski

2004-12-27T23:59:59.000Z

287

Performance parameters of a liquid filled ionization chamber array  

SciTech Connect

Purpose: In this work, the properties of the two-dimensional liquid filled ionization chamber array Octavius 1000SRS (PTW-Freiburg, Germany) for use in clinical photon-beam dosimetry are investigated.Methods: Measurements were carried out at an Elekta Synergy and Siemens Primus accelerator. For measurements of stability, linearity, and saturation effects of the 1000SRS array a Semiflex 31013 ionization chamber (PTW-Freiburg, Germany) was used as a reference. The effective point of measurement was determined by TPR measurements of the array in comparison with a Roos chamber (type 31004, PTW-Freiburg, Germany). The response of the array with varying field size and depth of measurement was evaluated using a Semiflex 31010 ionization chamber as a reference. Output factor measurements were carried out with a Semiflex 31010 ionization chamber, a diode (type 60012, PTW-Freiburg, Germany), and the detector array under investigation. The dose response function for a single detector of the array was determined by measuring 1 cm wide slit-beam dose profiles and comparing them against diode-measured profiles. Theoretical aspects of the low pass properties and of the sampling frequency of the detector array were evaluated. Dose profiles measured with the array and the diode detector were compared, and an intensity modulated radiation therapy (IMRT) field was verified using the Gamma-Index method and the visualization of line dose profiles.Results: The array showed a short and long term stability better than 0.1% and 0.2%, respectively. Fluctuations in linearity were found to be within ±0.2% for the vendor specified dose range. Saturation effects were found to be similar to those reported in other studies for liquid-filled ionization chambers. The detector's relative response varied with field size and depth of measurement, showing a small energy dependence accounting for maximum signal deviations of ±2.6% from the reference condition for the setup used. The ?-values of the Gaussian dose response function for a single detector of the array were found to be (0.72 ± 0.25) mm at 6 MV and (0.74 ± 0.25) mm at 15 MV and the corresponding low pass cutoff frequencies are 0.22 and 0.21 mm{sup ?1}, respectively. For the inner 5 × 5 cm{sup 2} region and the outer 11 × 11 cm{sup 2} region of the array the Nyquist theorem is fulfilled for maximum sampling frequencies of 0.2 and 0.1 mm{sup ?1}, respectively. An IMRT field verification with a Gamma-Index analysis yielded a passing rate of 95.2% for a 3 mm/3% criterion with a TPS calculation as reference.Conclusions: This study shows the applicability of the Octavius 1000SRS in modern dosimetry. Output factor and dose profile measurements illustrated the applicability of the array in small field and stereotactic dosimetry. The high spatial resolution ensures adequate measurements of dose profiles in regular and intensity modulated photon-beam fields.

Poppe, B.; Stelljes, T. S.; Looe, H. K.; Chofor, N. [Clinic for Radiation Therapy, Pius-Hospital, Oldenburg 26121, Germany and WG Medical Radiation Physics, Carl von Ossietzky University, Oldenburg 26121 (Germany)] [Clinic for Radiation Therapy, Pius-Hospital, Oldenburg 26121, Germany and WG Medical Radiation Physics, Carl von Ossietzky University, Oldenburg 26121 (Germany); Harder, D. [Prof. em., Medical Physics and Biophysics, Georg August University, Göttingen 37073 (Germany)] [Prof. em., Medical Physics and Biophysics, Georg August University, Göttingen 37073 (Germany); Willborn, K. [Clinic for Radiation Therapy, Pius-Hospital, Oldenburg 26121 (Germany)] [Clinic for Radiation Therapy, Pius-Hospital, Oldenburg 26121 (Germany)

2013-08-15T23:59:59.000Z

288

Observation of Muon Pairs in High-Energy Hadron Collisions  

Science Journals Connector (OSTI)

Muon pairs with effective masses between 1 GeV/c2 and 6.5 GeV/c2 have been observed in the collisions of 30-GeV protons with a uranium target. The production cross section was seen to vary smoothly with mass exhibiting no resonant structure. Data were taken at incident proton energies of 22, 25, 28.5, and 29.5 GeV. Within the experimental aperture the total cross section increased with energy by a factor of 5. The experimental results are compared with the predictions of several theoretical models. Limits are presented for the contributions to the signal from both massive muon-pair resonances and antiproton-proton annihilation. Implications are presented for higher-energy accelerators, using current ideas involving scaling.

J. H. Christenson, G. S. Hicks, L. M. Lederman, P. J. Limon, B. G. Pope, and E. Zavattini

1973-10-01T23:59:59.000Z

289

Pair production in counter-propagating laser beams  

E-Print Network (OSTI)

Based on an analysis of a specific electron trajectory in counter-propagating beams, Bell & Kirk (PRL 101, 200403 (2008)) recently suggested that laboratory lasers may shortly be able to produce significant numbers of electron-positron pairs. We confirm their results using an improved treatment of nonlinear Compton scattering in the laser beams. Implementing an algorithm that integrates classical electron trajectories, we then examine a wide range of laser pulse shapes and polarizations. We find that counter-propagating, linearly polarized beams, with either aligned or crossed orientation, are likely to initiate a pair avalanche at intensities of approximately 10^{24} Watts/sq cm per beam. The same result is found by modelling one of the beams as a wave reflected at the surface of an overdense solid.

J. G. Kirk; A. R. Bell; I. Arka

2009-06-24T23:59:59.000Z

290

NNLO W Pair Production at the LHC: Status Report  

E-Print Network (OSTI)

We discuss the result with full mass dependence for the virtual NNLO QCD corrections to the W boson pair production in the quark-anti-quark annihilation channel. We also report on our progress regarding the treatment of the double-real radiative corrections which, along with the virtual-real corrections, are the other two necessary ingredients for a theoretical prediction of the total cross section for W+ W- production to NNLO accuracy.

Grigorios Chachamis

2013-12-16T23:59:59.000Z

291

Interference of Cooper pairs emitted from independent superconductors  

SciTech Connect

We discuss the interference in the two-particle distribution of the electrons emitted from two independent superconductors. It is clarified that, while the interference appearing in the antibunching correlation is due to the Hanbury Brown and Twiss effect, that in the positive correlation due to superconductivity is intrinsically different and is nothing but the first-order interference of Cooper pairs emitted from different sources. This is the equivalent of the interference of two independent Bose-Einstein condensates.

Iazzi, Mauro [International School for Advanced Studies (SISSA), via Beirut 2-4, I-34014 Trieste (Italy); Yuasa, Kazuya [Waseda Institute for Advanced Study, Waseda University, Tokyo 169-8050 (Japan)

2010-05-01T23:59:59.000Z

292

Interference of Cooper pairs emitted from independent superconductors  

Science Journals Connector (OSTI)

We discuss the interference in the two-particle distribution of the electrons emitted from two independent superconductors. It is clarified that, while the interference appearing in the antibunching correlation is due to the Hanbury Brown and Twiss effect, that in the positive correlation due to superconductivity is intrinsically different and is nothing but the first-order interference of Cooper pairs emitted from different sources. This is the equivalent of the interference of two independent Bose-Einstein condensates.

Mauro Iazzi and Kazuya Yuasa

2010-05-04T23:59:59.000Z

293

Double Pair Production by Ultra High Energy Cosmic Ray Photons  

E-Print Network (OSTI)

With use of CompHEP package we've made the detailed estimate of the influence of double e+e- pair production by photons (DPP) on the propagation of ultra high energy electromagnetic cascade. We show that in the models in which cosmic ray photons energy reaches few thousand EeV refined DPP analysis may lead to substantial difference in predicted photon spectrum compared to previous rough estimates.

S. V. Demidov; O. E. Kalashev

2008-12-22T23:59:59.000Z

294

Fourier Transform Pairs The Fourier transform transforms a function of  

E-Print Network (OSTI)

Fourier Transform Pairs The Fourier transform transforms a function of time, f(t), into a function of frequency, F(s): F {f(t)}(s) = F(s) = Z - f(t)e- j2st dt. The inverse Fourier transform transforms a func. The inverse Fourier transform of the Fourier trans- form is the identity transform: f(t) = Z - Z - f()e- j2s

Masci, Frank

295

Observation of $?_{c1}$ decays into vector meson pairs $??$, $??$, and $??$  

E-Print Network (OSTI)

Decays of $\\chi_{c1}$ to vector meson pairs $\\phi\\phi$, $\\omega\\omega$ and $\\omega\\phi$ are observed for the first time using $(106\\pm4)\\times 10^6$ $\\psip$ events accumulated at the BESIII detector at the BEPCII $e^+e^-$ collider. The branching fractions are measured to be $(4.4\\pm 0.3\\pm 0.5)\\times 10^{-4}$, $(6.0\\pm 0.3\\pm 0.7)\\times 10^{-4}$, and $(2.2\\pm 0.6\\pm 0.2)\\times 10^{-5}$, for $\\chi_{c1}\\to \\phi\\phi$, $\\omega\\omega$, and $\\omega\\phi$, respectively. The observation of $\\chi_{c1}$ decays into a pair of vector mesons $\\phi\\phi$, $\\omega\\omega$ and $\\omega\\phi$ indicates that the hadron helicity selection rule is significantly violated in $\\chi_{cJ}$ decays. In addition, the measurement of $\\chi_{cJ}\\to \\omega\\phi$ gives the rate of doubly OZI-suppressed decay. Branching fractions for $\\chi_{c0}$ and $\\chi_{c2}$ decays into other vector meson pairs are also measured with improved precision.

M. Ablikim; M. N. Achasov; L. An; Q. An; Z. H. An; J. Z. Bai; R. Baldini; Y. Ban; J. Becker; N. Berger; M. Bertani; J. M. Bian; O. Bondarenko; I. Boyko; R. A. Briere; V. Bytev; X. Cai; G. F. Cao; X. X. Cao; J. F. Chang; G. Chelkova; G. Chen; H. S. Chen; J. C. Chen; M. L. Chen; S. J. Chen; Y. Chen; Y. B. Chen; H. P. Cheng; Y. P. Chu; D. Cronin-Hennessy; H. L. Dai; J. P. Dai; D. Dedovich; Z. Y. Deng; I. Denysenkob; M. Destefanis; Y. Ding; L. Y. Dong; M. Y. Dong; S. X. Du; M. Y. Duan; R. R. Fan; J. Fang; S. S. Fang; C. Q. Feng; C. D. Fu; J. L. Fu; Y. Gao; C. Geng; K. Goetzen; W. X. Gong; M. Greco; S. Grishin; M. H. Gu; Y. T. Gu; Y. H. Guan; A. Q. Guo; L. B. Guo; Y. P. Guo; X. Q. Hao; F. A. Harris; K. L. He; M. He; Z. Y. He; Y. K. Heng; Z. L. Hou; H. M. Hu; J. F. Hu; T. Hu; B. Huang; G. M. Huang; J. S. Huang; X. T. Huang; Y. P. Huang; T. Hussain; C. S. Ji; Q. Ji; X. B. Ji; X. L. Ji; L. K. Jia; L. L. Jiang; X. S. Jiang; J. B. Jiao; Z. Jiao; D. P. Jin; S. Jin; F. F. Jing; M. Kavatsyuk; S. Komamiya; W. Kuehn; J. S. Lange; J. K. C. Leung; Cheng Li; Cui Li; D. M. Li; F. Li; G. Li; H. B. Li; J. C. Li; Lei Li; N. B. Li; Q. J. Li; W. D. Li; W. G. Li; X. L. Li; X. N. Li; X. Q. Li; X. R. Li; Z. B. Li; H. Liang; Y. F. Liang; Y. T. Liang; G. R Liao; X. T. Liao; B. J. Liu; B. J. Liu; C. L. Liu; C. X. Liu; C. Y. Liu; F. H. Liu; Fang Liu; Feng Liu; G. C. Liu; H. Liu; H. B. Liu; H. M. Liu; H. W. Liu; J. P. Liu; K. Liu; K. Y Liu; Q. Liu; S. B. Liu; X. Liu; X. H. Liu; Y. B. Liu; Y. W. Liu; Yong Liu; Z. A. Liu; Z. Q. Liu; H. Loehner; G. R. Lu; H. J. Lu; J. G. Lu; Q. W. Lu; X. R. Lu; Y. P. Lu; C. L. Luo; M. X. Luo; T. Luo; X. L. Luo; C. L. Ma; F. C. Ma; H. L. Ma; Q. M. Ma; T. Ma; X. Ma; X. Y. Ma; M. Maggiora; Q. A. Malik; H. Mao; Y. J. Mao; Z. P. Mao; J. G. Messchendorp; J. Min; R. E. Mitchell; X. H. Mo; N. Yu. Muchnoi; Y. Nefedov; Z. Ning; S. L. Olsen; Q. Ouyang; S. Pacetti; M. Pelizaeus; K. Peters; J. L. Ping; R. G. Ping; R. Poling; C. S. J. Pun; M. Qi; S. Qian; C. F. Qiao; X. S. Qin; J. F. Qiu; K. H. Rashid; G. Rong; X. D. Ruan; A. Sarantsevc; J. Schulze; M. Shao; C. P. Shen; X. Y. Shen; H. Y. Sheng; M. R. Shepherd; X. Y. Song; S. Sonoda; S. Spataro; B. Spruck; D. H. Sun; G. X. Sun; J. F. Sun; S. S. Sun; X. D. Sun; Y. J. Sun; Y. Z. Sun; Z. J. Sun; Z. T. Sun; C. J. Tang; X. Tang; X. F. Tang; H. L. Tian; D. Toth; G. S. Varner; X. Wan; B. Q. Wang; K. Wang; L. L. Wang; L. S. Wang; M. Wang; P. Wang; P. L. Wang; Q. Wang; S. G. Wang; X. L. Wang; Y. D. Wang; Y. F. Wang; Y. Q. Wang; Z. Wang; Z. G. Wang; Z. Y. Wang; D. H. Wei; Q. G. Wen; S. P. Wen; U. Wiedner; L. H. Wu; N. Wu; W. Wu; Z. Wu; Z. J. Xiao; Y. G. Xie; G. F. Xu; G. M. Xu; H. Xu; Y. Xu; Z. R. Xu; Z. Z. Xu; Z. Xue; L. Yan; W. B. Yan; Y. H. Yan; H. X. Yang; M. Yang; T. Yang; Y. Yang; Y. X. Yang; M. Ye; M. H. Ye; B. X. Yu; C. X. Yu; L. Yu; C. Z. Yuan; W. L. Yuan; Y. Yuan; A. A. Zafar; A. Zallo; Y. Zeng; B. X. Zhang; B. Y. Zhang; C. C. Zhang; D. H. Zhang; H. H. Zhang; H. Y. Zhang; J. Zhang; J. W. Zhang; J. Y. Zhang; J. Z. Zhang; L. Zhang; S. H. Zhang; T. R. Zhang; X. J. Zhang; X. Y. Zhang; Y. Zhang; Y. H. Zhang; Z. P. Zhang; Z. Y. Zhang; G. Zhao; H. S. Zhao; Jiawei Zhao; Jingwei Zhao; Lei Zhao; Ling Zhao; M. G. Zhao; Q. Zhao; S. J. Zhao; T. C. Zhao; X. H. Zhao; Y. B. Zhao; Z. G. Zhao; Z. L. Zhao; A. Zhemchugova; B. Zheng; J. P. Zheng; Y. H. Zheng; Z. P. Zheng; B. Zhong; J. Zhong; L. Zhong; L. Zhou; X. K. Zhou; X. R. Zhou; C. Zhu; K. Zhu; K. J. Zhu; S. H. Zhu; X. L. Zhu; X. W. Zhu; Y. S. Zhu; Z. A. Zhu; J. Zhuang; B. S. Zou; J. H. Zou; J. X. Zuo; P. Zweber

2011-04-27T23:59:59.000Z

296

Observation of multiple ionization pathways for OCS in an intense laser field resolved by three-dimensional covariance mapping and visualized by hierarchical ionization topology  

SciTech Connect

The two- and three-body Coulomb explosion of carbonyl sulfide (OCS) by 790 nm, 50 fs laser pulses focused to {approx_equal}10{sup 16} W cm{sup -2} has been investigated by the three-dimensional covariance mapping technique. In a triatomic molecule, a single charge state, in this case the trication, has been observed to dissociate into two distinct energy channels. With the aid of a three-dimensional visualization technique to reveal the ionization hierarchy, evidence is presented for the existence of two sets of ionization pathways resulting from these two initial states. While one group of ions can be modeled using a classical enhanced ionization model, the second group, consisting of mainly asymmetric channels, cannot. The results provide clear evidence that an enhanced ionization approach must also be accompanied by an appreciation of the effects of excited ionic states and multielectronic processes.

Bryan, W. A.; Newell, W. R.; Sanderson, J. H.; Langley, A. J. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Department of Physics, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Central Laser Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom)

2006-11-15T23:59:59.000Z

297

Observation of multiple ionization pathways for OCS in an intense laser field resolved by three-dimensional covariance mapping and visualized by hierarchical ionization topology  

E-Print Network (OSTI)

The two- and three-body Coulomb explosion of carbonyl sulfide (OCS) by 790 nm, 50 fs laser pulses focussed to $\\approx $ 10$^{16}$ Wcm$^{-2}$ has been investigated by three-dimensional covariance mapping technique. For the first time in a triatomic molecule, a single charge state, in this case the trication, has been observed to dissociate into two distinct energy channels. With the aid of a three dimensional visualization technique to reveal the ionization hierarchy, evidence is presented for the existence of two sets of ionization pathways resulting from these two initial states. While one group of ions can be modeled using a Classical enhanced ionization model, the second group, consisting of mainly asymmetric channels, can not. The results provide clear evidence that an enhanced ionization approach must also be accompanied by an appreciation of the effects of excited ionic states and multi-electronic processes.

W. A. Bryan; W. R. Newell; J. H. Sanderson; A. J. Langley

2006-10-10T23:59:59.000Z

298

Densely Ionizing Radiation Acts via the Microenvironment to Promote Aggressive Trp53-Null Mammary Carcinomas  

Science Journals Connector (OSTI)

...Radiation Acts via the Microenvironment to Promote Aggressive Trp53-Null Mammary...changes from radiation contribute strongly to carcinogenic potential. Densely ionizing...radiation chimera in which mice were exposed to densely ionizing 350 MeV/amu Si-particles...

Irineu Illa-Bochaca; Haoxu Ouyang; Jonathan Tang; Christopher Sebastiano; Jian-Hua Mao; Sylvain V. Costes; Sandra Demaria; Mary Helen Barcellos-Hoff

2014-12-01T23:59:59.000Z

299

Atmospheric Ionization and Clouds as Links Between Solar Activity and Climate  

E-Print Network (OSTI)

) and CCN. Both IMN and electroscavenging depend on the presence of atmospheric ions that are generated direct condensation of water vapor in the ionization produced by GCR would not occur in the atmosphere1 Atmospheric Ionization and Clouds as Links Between Solar Activity and Climate Brian A. Tinsley1

Yu, Fangqun

300

ATM Requirement in Gene Expression Responses to Ionizing Radiation in Human Lymphoblasts and Fibroblasts  

Science Journals Connector (OSTI)

...St. Charles, MO) software program. A two-dimensional...analysis was done using software and methods as described...ATM kinase by ionizing radiation and phosphorylation...toxicology, and drug safety evaluation. Cancer...exposure to ionizing radiation. Radiat Res 2000...

Cynthia L. Innes; Alexandra N. Heinloth; Kristina G. Flores; Stella O. Sieber; Paula B. Deming; Pierre R. Bushel; William K. Kaufmann; and Richard S. Paules

2006-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

Electron spectroscopy study of single and double multiphoton ionization of strontium by visible picosecond laser light  

E-Print Network (OSTI)

795 Electron spectroscopy study of single and double multiphoton ionization of strontium by visible'ionisation multiphotonique simple et double du strontium par des impulsions picosecondes de 1011 à quelque 1012 W cm-2 initial un état excité de l'ion. Abstract. 2014 Multiphoton single and double ionization of strontium

Paris-Sud XI, Université de

302

Use of laser-induced ionization to detect soot inception in premixed flames  

SciTech Connect

Experimental measurements of laser-induced ionization were performed for ethene-air premixed flames operated near the soot inception point. Soot was ionized with a pulsed laser operated at 532 nm. The ionization signal was collected with a tungsten electrode located in the postflame region. Ionization signals were collected by use of both single-electrode and dual-electrode configurations. Earlier laser-induced- ionization studies focused on the use of a single biased electrode to generate the electric field, with the burner head serving as the path to ground. In many practical combustion systems, a path to ground is not readily available. To apply the laser-induced- ionization diagnostic to these geometries, a dual-electrode geometry must be employed. The influence of electrode configuration, flame equivalence ratio, and flame height on ionization signal detection was determined. The efficacy of the laser-induced-ionization diagnostic in detecting soot inception in the postflame region of a premixed flame by use of a dual-electrode configuration was investigated. Of the dual-electrode configurations tested, the dual-electrode geometry oriented parallel to the laser beam was observed to be most sensitive for detecting the soot inception point in a premixed flame.

Manzello, Samuel L.; Lee, Eui Ju; Mulholland, George W

2005-08-20T23:59:59.000Z

303

Retinal Degeneration and Ionizing Radiation Hypersensitivity in a Mouse Model for Cockayne Syndrome  

Science Journals Connector (OSTI)

...sensitive to a single dose of ionizing radiation at doses up to 10 Gy. In marked...least within the age range investigated, the...photoreceptor cells for ionizing radiation. This finding underscores...experiment (cumulative dose, 35 kJ/m2). The...

Theo G. M. F. Gorgels; Ingrid van der Pluijm; Renata M. C. Brandt; George A. Garinis; Harry van Steeg; Gerard van den Aardweg; Gerard H. Jansen; Jan M. Ruijter; Arthur A. B. Bergen; Dirk van Norren; Jan H. J. Hoeijmakers; Gijsbertus T. J. van der Horst

2006-12-04T23:59:59.000Z

304

Chromosome translocations and cosmic sources of ionizing radiation: The NIOSH-NCI airline pilot biomarker study  

Science Journals Connector (OSTI)

...and cosmic sources of ionizing radiation: The NIOSH-NCI airline...are exposed to cosmic ionizing radiation, an efficient inducer...bone marrow absorbed dose in cGy from personal...SD; 46.7 5.3, range 37-55 vs. 45.8...

Lee Yong; Alice Sigurdson; Elizabeth Ward; Martha Waters; Elizabeth Whelan; Martin Petersen; Elaine Ron; Marilyn Ramsey; Parveen Bhatti; and James Tucker

2007-05-01T23:59:59.000Z

305

Use of the Tetrazolium Assay in Measuring the Response of Human Tumor Cells to Ionizing Radiation  

Science Journals Connector (OSTI)

...irradiation dose rate was...demonstrated a range of absorbance...RESPONSE TO IONIZING RADIATION with 1 mg...with graded doses of irradiation...each with a range of seeded...MGHU1 0 5 10 DOSE (Gy) RT112...RESPONSE TO IONIZING RADIATION 150000 FF...

Patricia Price and Trevor J. McMillan

1990-03-01T23:59:59.000Z

306

Ionization of many-electron atoms by a quasistatic electric field Dimitri Fisher and Yitzhak Maron  

E-Print Network (OSTI)

Ionization of many-electron atoms by a quasistatic electric field Dimitri Fisher and Yitzhak Maron 1997 We present a general expression for the field ionization probability of atoms and ions under electron in the outer nl subshell, the expression obtained here is applicable to atoms and ions with any

307

Quantitative estimation of UV light dose concomitant to irradiation with ionizing radiation  

Science Journals Connector (OSTI)

A simple mathematical model for biological estimation of UV light dose concomitant to ionizing radiation was suggested. This approach was applied to determine the dependency of equivalent UV light dose accompanied by 100 Gy of ionizing radiation on energy of sparsely ionizing radiation and on volume of the exposed cell suspension. It was revealed that the relative excitation contribution to the total lethal effect and the value of UV dose was greatly increased with an increase in energy of ionizing radiation and volume of irradiated suspensions. It is concluded that these observations are in agreement with the supposition that ?erenkov emission is responsible for the production of UV light damage and the phenomenon of photoreactivation observed after ionizing exposure of bacterial and yeast cells hypersensitive to UV light. A possible synergistic interaction of the damages produced by ionizations and excitations as well as a probable participation of UV component of ionizing radiation in the mechanism of hormesis and adaptive response observed after ionizing radiation exposure is discussed.

Vladislav G. Petin; Ivan I. Morozov; Jin Kyu Kim; Maria A. Semkina

2011-01-01T23:59:59.000Z

308

Physiological Responses of the Hyperthermophilic Archaeon “Pyrococcus abyssi” to DNA Damage Caused by Ionizing Radiation  

Science Journals Connector (OSTI)

...before and after radiation and was in good...performed at a sublethal dose of 2,000 Gy to...our preliminary estimation reveals that 0...been observed for radiation-resistant Chroococcidiopsis...caused by ionizing radiation. | The mechanisms...furiosus, survive high doses of ionizing gamma...

Edmond Jolivet; Fujihiko Matsunaga; Yoshizumi Ishino; Patrick Forterre; Daniel Prieur; Hannu Myllykallio

2003-07-01T23:59:59.000Z

309

Above-threshold ionization near the 3p4d 1 autoionizing state in magnesium  

E-Print Network (OSTI)

Above-threshold ionization near the 3p4d 1 Fo autoionizing state in magnesium A. Reber,1 T. Baynard ionization of magnesium from the 3 1 P state in the region of the 3p4d 1 Fo autoionizing resonance, in which of magnesium atoms just inside the focus of a magnetic bottle spectrometer MBS 13 . One laser is tuned

Berry, R. Stephen

310

Two-photon above-threshold ionization of magnesium F. Martin,2  

E-Print Network (OSTI)

Two-photon above-threshold ionization of magnesium A. Reber,1 F. Marti´n,2 H. Bachau,3 and R. S to understanding the photoionization properties of magnesium 1­8 , the problem of above- threshold ionization ATI

Berry, R. Stephen

311

Electron-Nuclear Energy Sharing in Above-Threshold Multiphoton Dissociative Ionization of H2  

E-Print Network (OSTI)

Electron-Nuclear Energy Sharing in Above-Threshold Multiphoton Dissociative Ionization of H2 J. Wu­4], where the photon energy is shared by the freed electrons and the nuclear fragments. For the molecular ionization [10­15], and the imaging of inter- nuclear distance using nuclear kinetic energy release spec- tra

Thumm, Uwe

312

Near-infrared femtosecond laser machining initiated by ultraviolet multiphoton ionization  

E-Print Network (OSTI)

Near-infrared femtosecond laser machining initiated by ultraviolet multiphoton ionization X. Yu, Q://apl.aip.org/features/most_downloaded Information for Authors: http://apl.aip.org/authors #12;Near-infrared femtosecond laser machining initiated, and the near-infrared pulse utilizes these electrons to cause damage by avalanche ionization. VC 2013 American

Van Stryland, Eric

313

FEATURE ARTICLE Photoexcitation, Ionization, and Dissociation of Molecules Using Intense Near-Infrared  

E-Print Network (OSTI)

FEATURE ARTICLE Photoexcitation, Ionization, and Dissociation of Molecules Using Intense Near-Infrared The coupling mechanism between an intense (1013 W cm-2, 780 nm) near-infrared radiation field of duration 50 above threshold dissociation,3 multiple electron emission,4 and mo- lecular ionization using near-infrared

Levis, Robert J.

314

Laser vaporization/ionization interface for coupling microscale separation techniques with mass spectrometry  

DOE Patents (OSTI)

The present invention provides a laser-induced vaporization and ionization interface for directly coupling microscale separation processes to a mass spectrometer. Vaporization and ionization of the separated analytes are facilitated by the addition of a light-absorbing component to the separation buffer or solvent. 8 figs.

Yeung, E.S.; Chang, Y.C.

1999-06-29T23:59:59.000Z

315

Desorption Electrospray Ionization Mass Spectrometry for Trace Analysis of Agrochemicals in Food  

Science Journals Connector (OSTI)

Desorption Electrospray Ionization Mass Spectrometry for Trace Analysis of Agrochemicals in Food ... Desorption electrospray ionization (DESI) is applied to the rapid, in situ, direct qualitative and quantitative (ultra)trace analysis of agrochemicals in foodstuffs. ... The results proved that DESI allows the detection and confirmation of traces of agrochemicals in actual market-purchased samples. ...

Juan F. García-Reyes; Ayanna U. Jackson; Antonio Molina-Díaz; R. Graham Cooks

2008-12-17T23:59:59.000Z

316

Title of Dissertation: MODELING LASER PULSE EVOLUTION IN IONIZING GAS AND PLASMA WITH  

E-Print Network (OSTI)

ABSTRACT Title of Dissertation: MODELING LASER PULSE EVOLUTION IN IONIZING GAS AND PLASMA to model propagation in tenuous gas and plasma and we provide relevant information about the validation energy distribution. #12;MODELING LASER PULSE EVOLUTION IN IONIZING GAS AND PLASMA WITH APPILCATION

Anlage, Steven

317

Effects of atomic disorder on impact ionization rate in silicon nanodots  

SciTech Connect

We theoretically investigate effects of atomic disorder existing near the Si/SiO{sub 2} interfaces on the impact ionization rate of a Si nanodot (SiND). We find that the impact ionization rate of a disordered SiND becomes higher near the threshold energy and approaches that of an ideal SiND for higher energy region.

Mori, N.; Minari, H. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan and CREST, JST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Tomita, M. [Faculty of Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Watanabe, T. [Faculty of Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555, Japan and CREST, JST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Koshida, N. [Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan)

2013-12-04T23:59:59.000Z

318

Low Dose Ionizing Radiation Modulates Immune Function New Project Overview  

NLE Websites -- All DOE Office Websites (Extended Search)

Modulates Immune Function New Project Overview Modulates Immune Function New Project Overview Gregory Nelson Loma Linda University Abstract The immune system provides the first line of defense for exposures to environmental hazards. Protective immunity mechanisms using innate or adaptive responses are employed to mitigate acute challenges or amplify the readiness of the system to respond to future challenges. Some stimuli lead to amplified inflammatory reactions such as delayed hypersensitivity which is required for immunity to parasites and can also lead to adverse consequences such as contact dermatitis. Radiation exposure has the potential to aggravate hypersensitivity reactions as well as to suppress protective immunity. Ionizing radiation at high doses has long been recognized as highly effective in destroying cells of the immune system,

319

Effects of ionizing radiation on modern ion exchange materials  

SciTech Connect

We review published studies of the effects of ionizing radiation on ion exchange materials, emphasizing those published in recent years. A brief overview is followed by a more detailed examination of recent developments. Our review includes styrene/divinylbenzene copolymers with cation-exchange or anion-exchange functional groups, polyvinylpyridine anion exchangers, chelating resins, multifunctional resins, and inorganic exchangers. In general, strong-acid cation exchange resins are more resistant to radiation than are strong-base anion exchange resins, and polyvinylpyridine resins are more resistant than polystyrene resins. Cross-linkage, salt form, moisture content, and the surrounding medium all affect the radiation stability of a specific exchanger. Inorganic exchangers usually, but not always, exhibit high radiation resistance. Liquid ion exchangers, which have been used so extensively in nuclear processing applications, also are included.

Marsh, S.F.; Pillay, K.K.S.

1993-10-01T23:59:59.000Z

320

Debye-Onsager relaxation effect in fully ionized plasmas  

Science Journals Connector (OSTI)

We consider the virial expansion of the inverse conductivity in fully ionized plasmas ?-1=A(T)ln n+B(T)+C(T)n1/2ln n+O(n1/2) and the coefficient C(T), which is related to the Debye-Onsager relaxation effect, is evaluated in the nondegenerate case. In analogy to the Chapman-Enskog treatment of the Boltzmann equation, a moment expansion to evaluate C(T) is presented. Including the two-particle distribution in the generalized linear response theory, the original Onsager result is recovered within a hydrodynamic approximation. Improved results for the relaxation effect beyond this approximation are obtained considering higher moments of the two-particle distribution function.

A. Esser and G. Röpke

1998-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

Heating and Ionization of the Primordial Intergalactic Medium by High Mass X-ray Binaries  

E-Print Network (OSTI)

We investigate the influence of High Mass X-ray Binaries on their high redshift environments. Using a one-dimensional radiative transfer code, we predict the ionization and temperature profiles surrounding a coeval stellar population, composed of main sequence stars and HMXBs, at various times after its formation. We consider both uniform density surroundings, and a cluster embedded in a 10^8 solar mass NFW halo. HMXBs in a constant density environment produce negligible enhanced ionization because of their high-energy SEDs and short lifetimes. In this case, HMXBs only marginally contribute to the local heating rate. For NFW profiles, radiation from main sequence stars cannot prevent the initially ionized volume from recombining since it is unable to penetrate the high density galactic core. However, HMXB photons stall recombinations behind the front, keeping it partially ionized for longer. The increased electron density in these partially ionized regions promotes further cooling, resulting in lower IGM temp...

Knevitt, Gillian; Power, Chris; Bolton, James

2014-01-01T23:59:59.000Z

322

Radial arrays of nano-electrospray ionization emitters and methods of forming electrosprays  

DOE Patents (OSTI)

Electrospray ionization emitter arrays, as well as methods for forming electrosprays, are described. The arrays are characterized by a radial configuration of three or more nano-electrospray ionization emitters without an extractor electrode. The methods are characterized by distributing fluid flow of the liquid sample among three or more nano-electrospray ionization emitters, forming an electrospray at outlets of the emitters without utilizing an extractor electrode, and directing the electrosprays into an entrance to a mass spectrometry device. Each of the nano-electrospray ionization emitters can have a discrete channel for fluid flow. The nano-electrospray ionization emitters are circularly arranged such that each is shielded substantially equally from an electrospray-inducing electric field.

Kelly, Ryan T [West Richland, WA; Tang, Keqi [Richland, WA; Smith, Richard D [Richland, WA

2010-10-19T23:59:59.000Z

323

E-Print Network 3.0 - atom-photon pair laser Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

photon pair laser Search Powered by Explorit Topic List Advanced Search Sample search results for: atom-photon pair laser Page: << < 1 2 3 4 5 > >> 1 Observation of Entanglement of...

324

E-Print Network 3.0 - associative pairing enhances Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

PCR output was enhanced only... was enhanced by at least one of the three preCESs. For primer pairs B and G, which have not resulted in any... . For primer pairs C, D, H, L, or I,...

325

Molecular Hydrogen Formation from Proximal Glycol Pairs on TiO2...  

NLE Websites -- All DOE Office Websites (Extended Search)

Hydrogen Formation from Proximal Glycol Pairs on TiO2(110). Molecular Hydrogen Formation from Proximal Glycol Pairs on TiO2(110). Abstract: Understanding hydrogen formation on TiO2...

326

TEMPERATURE DEPENDENCE OF THE THRESHOLD ENERGY FOR FRENKEL PAIR PRODUCTION IN COPPER  

E-Print Network (OSTI)

FRENKEL PAIR PRODUCTION IN COPPER R. Drosd, T. Kosel, and J.FRENKEL PAIR PRODUCTION IN COPPER R. Drosd, T. Kosel and J.110) foils of high purity copper in the HVEM. At 575°K loops

Drosd, jR.

2010-01-01T23:59:59.000Z

327

Hydrogen and fluorine migration in photo-double-ionization of 1,1-difluoroethylene (1,1-C2H2F2) near and above threshold  

E-Print Network (OSTI)

and fluorine migration in photo-double-ionization of 1,1-nondissociative and dissociative photo-double-ionization ofdirect and indirect photo-double-ionization mechanisms at a

Gaire, B.

2014-01-01T23:59:59.000Z

328

WARM IONIZED GAS REVEALED IN THE MAGELLANIC BRIDGE TIDAL REMNANT: CONSTRAINING THE BARYON CONTENT AND THE ESCAPING IONIZING PHOTONS AROUND DWARF GALAXIES  

SciTech Connect

The Magellanic System includes some of the nearest examples of galaxies disturbed by galaxy interactions. These interactions have redistributed much of their gas into the halos of the Milky Way (MW) and the Magellanic Clouds. We present Wisconsin H{alpha} Mapper kinematically resolved observations of the warm ionized gas in the Magellanic Bridge over the velocity range of +100 to +300 km s{sup -1} in the local standard of rest reference frame. These observations include the first full H{alpha} intensity map and the corresponding intensity-weighted mean velocity map of the Magellanic Bridge across (l, b) = (281 Degree-Sign .5, -30 Degree-Sign .0) to (302. Degree-Sign 5, -46. Degree-Sign 7). Using the H{alpha} emission from the Small Magellanic Cloud (SMC)-Tail and the Bridge, we estimate that the mass of the ionized material is between (0.7-1.7) Multiplication-Sign 10{sup 8} M{sub Sun }, compared to 3.3 Multiplication-Sign 10{sup 8} M{sub Sun} for the neutral mass over the same region. The diffuse Bridge is significantly more ionized than the SMC-Tail, with an ionization fraction of 36%-52% compared to 5%-24% for the Tail. The H{alpha} emission has a complex multiple-component structure with a velocity distribution that could trace the sources of ionization or distinct ionized structures. We find that incident radiation from the extragalactic background and the MW alone are insufficient to produced the observed ionization in the Magellanic Bridge and present a model for the escape fraction of the ionizing photons from both the SMC and Large Magellanic Cloud (LMC). With this model, we place an upper limit of 4.0% for the average escape fraction of ionizing photons from the LMC and an upper limit of 5.5% for the SMC. These results, combined with the findings of a half a dozen other studies for dwarf galaxies in different environments, provide compelling evidence that only a small percentage of the ionizing photons escape from dwarf galaxies in the present epoch to influence their surroundings.

Barger, K. A.; Haffner, L. M. [Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53706 (United States); Bland-Hawthorn, J., E-mail: kbargers@nd.edu, E-mail: haffner@astro.wisc.edu, E-mail: jbh@physics.usyd.edu.au [Sydney Institute for Astronomy, School of Physics A28, University of Sydney, NSW 2006 (Australia)

2013-07-10T23:59:59.000Z

329

The distribution of cosmic-ray ionization rates in diffuse molecular clouds as probed by H3+  

Science Journals Connector (OSTI)

...Chemistry, astronomy and physics of H3+ organized and...cosmic-ray ionization rates in diffuse molecular...jhu.edu Department of Physics and Astronomy, Johns...assume that the ionization rate does not pass below some value set...

2012-01-01T23:59:59.000Z

330

Possible diminution of impurity pair breaking for triplet pairing superconductivity in two-dimensional or quasi-two-dimensional, weakly localized, nearly magnetic systems  

SciTech Connect

We propose a conjecture according to which, as a consequence of weak localization in two-dimensional, nearly magnetic itinerant paramagnets, the pair-breaking parameter due to normal impurity scattering, in triplet pairing superconductivity, may be reduced at low enough temperature. It might then, in principle, become easier to observe triplet pairing superconductivity in dirty two-dimensional or quasi-two-dimensional metals, than in three-dimensional ones; thus some recently observed puzzling superconductive behaviors should be reexamined.

Beal-Monod, M.T.; Ebisawa, H.; Fukuyama, H.

1984-08-01T23:59:59.000Z

331

Cross sections and energy loss for lepton pair production in muon transport  

E-Print Network (OSTI)

We reevaluate electron-positron pair production from electromagnetic interactions of muons in transit through materials. Our approach, through the use of structure functions for inelastic and elastic scattering and including hadronic recoil, make the formalism useful for tau pair production at high energies. Our results for electron-positron pair production agree well with prior evaluations. Tau pair production, has a significant contribution from inelastic scattering in addition to the usual coherent scattering with the nucleus and scattering with atomic electrons.

A. Bulmahn; M. H. Reno

2008-12-30T23:59:59.000Z

332

Fluctuation Driven FirstOrder Pairing Transition of ChernSimons N.E. Bonesteel  

E-Print Network (OSTI)

­dimensional electron gas at Landau level filling factor š = 1=2 can be viewed as a `Fermi sea' of composite fermions 2 pairing for weak enough attraction and drive the pairing transition which occurs as the attraction natural to ask what effect the CS gauge field may have on BCS pairing. In this short note I introduce

Bonesteel, Nicholas E.

333

R-Axion: A New LHC Physics Signature Involving Muon Pairs  

Science Journals Connector (OSTI)

......decays into a pair of muons and leaves a displaced...Ibe M. J. High Energy Phys. (2009) 03...T. T. J. High Energy Phys. (2009) 04...Signature Involving Muon Pairs~) Hock-Seng...Signature Involving Muon Pairs 29 2. Interactions...sectors, the low energy effective theory......

Hock-Seng Goh; Masahiro Ibe

2009-04-01T23:59:59.000Z

334

Experiences with a two terminal-pair digital impedance bridge  

E-Print Network (OSTI)

This paper describes the realization of a two terminal-pair digital impedance bridge and the test measurements performed with it. The bridge, with a very simple architecture, is based on a commercial two-channel digital signal synthesizer and a synchronous detector. The bridge can perform comparisons between impedances having arbitrary phase and magnitude ratio: its balance is achieved automatically in less than a minute. $R$-$C$ comparisons with calibrated standards, at kHz frequency and 100 kohm magnitude level, give ratio errors of the order of $10^{-6}$, with potential for further improvements.

Callegaro, Luca; Kampik, Marian; Kim, Dan Bee; Ortolano, Massimo; Pourdanesh, Faranak

2014-01-01T23:59:59.000Z

335

Radiative emission of neutrino pair free of quantum electrodynamic backgrounds  

E-Print Network (OSTI)

A scheme of quantum electrodynamic (QED) background-free radiative emission of neutrino pair (RENP) is proposed in order to achieve precision determination of neutrino properties so far not accessible. The important point for the background rejection is the fact that the dispersion relation between wave vector along propagating direction in wave guide (and in a photonic-crystal type fiber) and frequency is modified by a discretized non-vanishing effective mass. This effective mass acts as a cutoff of allowed frequencies, and one may select the RENP photon energy region free of all macro-coherently amplified QED processes by choosing the cutoff larger than the mass of neutrinos.

Yoshimura, M; Tanaka, M

2015-01-01T23:59:59.000Z

336

Holographic Accelerated Heavy Quark-Anti-Quark Pair  

E-Print Network (OSTI)

The problem of a heavy quark-anti-quark pair which have constant eternal acceleration in opposite directions in the vacuum of deconfined maximally supersymmetric Yang-Mills theory is studied both in perturbation theory and at strong coupling using AdS/CFT. Perturbation theory is summed to obtain what is conjectured to be an exact result. It is shown to agree with a particular prescription for computing the disc amplitude in the string theory dual and it yields a value $s=\\sqrt{\\lambda}$ for the entanglement entropy of the quark and anti-quark.

Veronika E. Hubeny; Gordon W. Semenoff

2014-10-05T23:59:59.000Z

337

Radiative emission of neutrino pair free of quantum electrodynamic backgrounds  

E-Print Network (OSTI)

A scheme of quantum electrodynamic (QED) background-free radiative emission of neutrino pair (RENP) is proposed in order to achieve precision determination of neutrino properties so far not accessible. The important point for the background rejection is the fact that the dispersion relation between wave vector along propagating direction in wave guide (and in a photonic-crystal type fiber) and frequency is modified by a discretized non-vanishing effective mass. This effective mass acts as a cutoff of allowed frequencies, and one may select the RENP photon energy region free of all macro-coherently amplified QED processes by choosing the cutoff larger than the mass of neutrinos.

M. Yoshimura; N. Sasao; M. Tanaka

2015-01-23T23:59:59.000Z

338

Metal Absorption Systems in Spectra of Pairs of QSOs  

E-Print Network (OSTI)

We present the first large sample of absorption systems in paired QSOs consisting of 691 absorption systems in the spectra of 310 QSOs including 170 pairings. All these absorption systems have metal lines, usually C IV or Mg II. We see 17 cases of absorption in one line-of-sight within 200 km/s (1 Mpc) of absorption in the paired line-of-sight with the probability at least approx 50% at 100kpc, declining rapidly to 23% at 100 - 200 kpc. We detect clustering on 0.5Mpc scales and see a hint of the "fingers of God" redshift-space distortion. The distribution matches absorbers arising in galaxies at z=2 with a normal correlation function and systematic infall velocities but unusually low random pair-wise velocity differences. Absorption in gas flowing out from galaxies at a mean velocity of 250 km/s would produce vastly more elongation than we see. The UV absorption from fast winds that Adelberger et al. 2005 see in spectra of LBGs is not representative of the absorption that we see. Either the winds are confined to LBGs, or they can not extend to 40 kpc with large velocities, while continuing to make UV absorption we see, implying most metals were in place in the IGM long before z=2. Separately, when we examine the absorption seen when a sight line passes a second QSO, we see 19 absorbers within 400 km/s of the partner QSO. The probability of seeing absorption is approximately constant for impact parameters 0.1 - 1.5 Mpc. Perhaps we do not see a rapid rise in the probability at small impact parameters because the UV from QSOs destroys some absorbers near to the QSOs. The 3D distribution of 64 absorbers around 313 QSOs is to first order isotropic, with just a hint of the anisotropy expected if the QSO UV emission is beamed, or alternatively QSOs might emit UV isotropically but for a surprisingly short time of only 0.3Myr.

David Tytler; Mark Gleed; Carl Melis; Angela Chapman; David Kirkman; Dan Lubin; Pascal Paschos; Tridivesh Jena; Arlin P. S. Crotts

2007-11-15T23:59:59.000Z

339

Measurement of $\\psi(2S)$ decays to baryon pairs  

E-Print Network (OSTI)

A sample of 3.95M $\\psi(2S)$ decays registered in the BES detector are used to study final states containing pairs of octet and decuplet baryons. We report branching fractions for $\\psi(2S)\\to p\\bar{p}$, $\\Lambda\\bar{\\Lambda}$, $\\Sigma^0\\bar{\\Sigma}{}^0$, $\\Xi^-\\bar{\\Xi}{}^+$, $\\Delta^{++}\\bar{\\Delta}{}^{--}$, $\\Sigma^+(1385)\\bar{\\Sigma}{}^-(1385 )$, $\\Xi^0(1530)\\bar{\\Xi}{}^0(1530)$, and $\\Omega^-\\bar{\\Omega}{}^+$. These results are compared to expectations based on the SU(3)-flavor symmetry, factorization, and perturbative QCD.

Bai, J Z; Bian, J G; Blum, I K; Chen, A D; Chen, G P; Chen, H F; Chen, H S; Chen, J; Chen Jia Chao; Chen, X D; Chen, Y; Chen, Y B; Cheng Bao Sen; Choi, J B; Cui, X Z; Ding, H L; Dong, L Y; Du, Z Z; Dunwoodie, W M; Gao, C S; Gao, M L; Gao, S Q; Gratton, P; Gu, J H; Gu, S D; Gu, W X; Guo, Y N; Guo, Z J; Han, S W; Han, Y; Harris, F A; He, J; He, J T; He, K L; He, M; Heng, Y K; Hitlin, D G; Hu, G Y; Hu, H M; Hu, J L; Hu, Q H; Hu, T; Huang, G S; Huang, X P; Huang, Y Z; Izen, J M; Jiang, C H; Jin, Y; Jones, B D; Ju, X; Kang, J S; Ke, Z J; Kelsey, M H; Kim, B K; Kim, H J; Kim, S K; Kim, T Y; Kong, D; Lai, Y F; Lang, P F; Lankford, A J; Li, C G; Li, D; Li, H B; Li, J; Li, J C; Li, P Q; Li, W; Li, W G; Li, X H; Li Xiao Nan; Li Xue Qian; Li Zhong Chao; Liu, B; Liu, F; Liu Feng; Liu, H M; Liu, J; Liu, J P; Liu, R G; Liu, Y; Liu, Z X; Lou, X C; Lowery, B; Lu, G R; Lu, F; Lu, J G; Luo, X L; Ma, E C; Ma, J M; Malchow, R L; Mao, H S; Mao, Z P; Meng, X C; Mo, X H; Nie, J; Olsen, S L; Oyang, J Y T; Paluselli, D; Pan, L J; Panetta, J; Park, H; Porter, F; Qi, N D; Qi, X R; Qian, C D; Qiu, J F; Qu, Y H; Que, Y K; Rong, G; Schernau, M; Shao, Y Y; Shen, B W; Shen, D L; Shen, H; Shen, H Y; Shen, X Y; Shi, F; Shi, H Z; Song, X F; Standifird, J; Suh, J Y; Sun, H S; Sun, L F; Sun, Y Z; Tang, S Q; Toki, W; Tong, G L; Varner, G S; Wang, F; Wang, L; Wang, L S; Wang, L Z; Wang, P; Wang, P L; Wang, S M; Wang, Y Y; Wang, Z Y; Weaver, M; Wei, C L; Wu, N; Wu, Y G; Xi, D M; Xia, X M; Xie, Y; Xie, Y H; Xu, G F; Xue, S T; Yan, J; Yan, W G; Yang, C M; Yang, C Y; Yang, H X; Yang, W; Yang, X F; Ye, M H; Ye Shu Wei; Ye, Y X; Yu, C S; Yu, C X; Yu, G W; Yu Yu Hei; Yu, Z Q; Yuan, C Z; Yuan, Y; Zhang Bing Yun; Zhang, C; Zhang, C C; Zhang, D H; De Hong Zhang; Zhang, H L; Zhang, J; Zhang, J W; Zhang, L; Zhang Lei; Zhang, L S; Zhang, P; Zhang, Q J; Zhang, S Q; Zhang, X Y; Zhang, Y Y; Zhao, D X; Zhao, H W; Jia Wei Zhao; Zhao Jia Wei; Zhao, M; Zhao Wei Ren; Zhao, Z G; Zheng Jian Ping; Zheng Lin Sheng; Zheng Zhi Peng; Zhou, B Q; Zhou, L; Zhu, K J; Zhu, Q M; Zhu, Y C; Zhu, Y S; Zhu, Z A; Zhuang, B A

2001-01-01T23:59:59.000Z

340

Polarization Correlations in Pair Production from Charged and Neutral Strings  

E-Print Network (OSTI)

Polarization correlations of $e^{+}e^{-}$ pair productions from charged and neutral Nambu strings are investigated, via photon and graviton emissions, respectively and explicit expressions for their corresponding probabilities are derived and found to be \\textit{speed} dependent. The strings are taken to be circularly oscillating closed strings, as perhaps the simplest solution of the Nambu action. In the extreme relativistic case, these probabilities coincide, but, in general, are different, and such inquiries, in principle, indicate whether the string is charged or uncharged. It is remarkable that these dynamical relativistic quantum field theory calculations lead to a clear violation of Local Hidden Variables theories.

E. B. Manoukian; N. Yongram

2005-04-25T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

Deuterium Ionization For Pyroelectric Crystal Accelerators Don Gillich, Yaron Danon, Jeffrey A. Geuther, Becky Marus, Brian McDermott  

E-Print Network (OSTI)

Deuterium Ionization For Pyroelectric Crystal Accelerators Don Gillich, Yaron Danon, Jeffrey A in realizing pyroelectric fusion is to ionize and accelerate deuterium gas toward a deuterated target to ionize and accelerate D2 gas through a magnetic field. An ion detection system including a zinc sulfide

Danon, Yaron

342

Theory of ionization-induced trapping in laser-plasma accelerators M. Chen, E. Esarey,a)  

E-Print Network (OSTI)

Theory of ionization-induced trapping in laser-plasma accelerators M. Chen, E. Esarey,a) C. B) Ionization injection in a laser-plasma accelerator is studied analytically and by multi-dimensional particle acceleration. For a broad laser pulse, ionization injection requires a minimum normalized laser field of a0 ' 1

Geddes, Cameron Guy Robinson

343

Chemi-ionization reactions involving metastable helium atoms at high energy P. Pradel and J. J. Laucagne  

E-Print Network (OSTI)

1263 Chemi-ionization reactions involving metastable helium atoms at high energy P. Pradel and J. J dépend du défaut d'énergie de la réaction. Abstract - Total chemi-ionization cross-sections have been. Introduction. Over the last decade the chemi-ionization of atomic or molecular gases by metastable helium

Paris-Sud XI, Université de

344

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.

345

Electrospray Ionization Mass Spectrometry of hexanitrohexaazaisowurtzitane (CL-20)  

SciTech Connect

Hexanitrohexaazaisowurtzitane, (C6H6N12O12, MW 438) {CL-20}, is a high-energy propellent that has been recently developed and successfully tested (Nielsen et al. 1998). CL-20 releases more energy on ignition and is more stable to accidental detonation than currently used energetic materials. It is expected to replace many of the energetic materials currently being used by the Department of Defense (DoD). The EPA method 8330 (EPA 1997) for the analysis of explosives and metabolites in soils calls for the use of UV/Vis detection. High performance liquid chromatography has been used to quantify CL-20 and precursor concentration (Bazaki et al. 1998`) at relatively high concentrations. Fourier transform infrared (FTIR) spectroscopy has been used to identify different crystal forms of CL-20 (4 isomers; Kim et al. 1998). Campbell et al. (1997) utilized particle beam mass spectrometry for the analysis of enzymatic degradation of explosives. Introduction and recent improvements of ionization techniques such as electrospray (ES) have allowed the mass spectrometer to become more widely used in liquid chromatography. Schilling(1996) also examined explosive components and metabolites using electrospray (ES) and atmospheric pressure chemical ionization (APCI) liquid chromatography/mass spectrometry (LC/MS). Schilling’s results showed that compared to thermospray LC/MS, APCI and ES were more sensitive than thermospray by at least an order of magnitude. 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), 10 nitroso-RDX metabolites, and other munitions in ground water have been analyzed using solid phase extraction and isotope dilution liquid chromatography-APCI mass spectrometry (Cassada et al. 1999). The method detection limits indicate that nitramine and nitroaromatic compounds can be routinely determined in ground water samples using electrospray LC/MS with concentration techniques utilizing solid-phase extraction. Miller et al. (1996) studied nitrated explosives with mobile phase additives to enhance the ESI intensities and spectral consistencies. Several of the explosives gave nitrate adduct ions in the negative mode with ammonium nitrate as the mobile phase. The nitramines RDX and 1,3,5,7-tetranitro-1,3,5,7 tetraazacyclooctane (HMX) showed the greatest enhancement in response of the explosives. Ammonium nitrate was used as the mobile phase and made it possible to obtain consistent and interpretable LC/MS spectra at the nanogram level. Campbell et al. (1999), Shi et al. (2000), and Goheen et al. (1999) utilized electrospray ionization mass spectrometry for the identification of degradation products of explosives. Yinon et al. (1997) used ESI and tandem mass spectrometry collision-induced dissociation to examine several nitramine compounds including trinitrotolutene (TNT), RDX, and pentaerythritol tetranitrate (PETN). The results indicate that explosives can be detected in the negative ion mode and characterized by various adduct ions. As an example, for nitroglycerin, the major adduct ion observed was (M+ONO2)-. In addition, Harvey et al. (1992) have used direct probe mass spectrometry for the analysis of degradation products of tetryl and its transformation products in soil. The negative ion electrospray mass spectrum of CL-20 is reported here. The major adduct ions observed under negative ion conditions were (M+Cl)- at m/z 473 and (M+ONO2) – at m/z 500. In addition, the results of mass spectrometry/mass spectrometry studies are also discussed.

Campbell, James A.; Szecsody, Jim E.; Devary, Brooks J.; Valenzuela, Blandina R.

2007-09-03T23:59:59.000Z

346

ANALYSIS OF SULFONATES IN AQUEOUS SAMPLES BY ION-PAIR LC/ESI-MS/MS WITH IN-SOURCE CID FOR ADDUCT PEAK ELIMINATION  

SciTech Connect

Determination of low-molecular-weight organic sulfonates (e.g. taurine and cysteic acid) in aqueous solutions is important in many applications of biological, environmental and pharmaceutical sciences. These compounds are difficult to be determined by commonly used reversed-phase liquid chromatographic separation combined with UV-Visible detection because of their high solubility and the lack chromophoric moieties. Here the authors report a method combining ion-pair liquid chromatography and electrospray ionization tandem mass spectrometry (IPLC/ESI-MS/MS)for determining sulfonates. The ability of low-molecular-weight sulfonates to form ion-pairs with quaternary ammonium cations in aqueous solutions allowed LC separation with a C{sub 18} column. Detection of the sulfonates was accomplished with ESI-MS that lends a universal mode of mass detection for polar, water soluble compounds. An in-source collision induced dissociation (CID) was applied to eliminate the adduct peaks in mass spectra. Characteristic marker ions showed in the second stage mass spectra lent a method for identifying sulfonates.

OUYANG,S.; VAIRAVAMURTHY,M.A.

1999-06-13T23:59:59.000Z

347

Muon pairs from In+In collision at SPS energy  

E-Print Network (OSTI)

NA60 collaboration has extracted the inverse slope parameters, T_{eff} of the dimuon spectra originating from the In+In collisions at root(s_NN)=17.3 GeV for various invariant mass region. They have observed that the inverse slope parameter as a function of invariant mass of the lepton pair drops beyond the rho-peak. In the present work, first we reproduce the observed invariant mass and transverse momentum spectra of the muon pairs. Then show that the slope parameters extracted from the transverse momentum distributions for various invariant mass region windows can be explained by assuming formation of a partonic phase initially which reverts to hadronic phase through a weak first order phase transition at a temperature T_c ~ 175 MeV. It is observed that a scenario without the formation of a partonic phase does not reproduce the non-monotonic behaviour of the inverse slope parameter non typical of radial flow.

Jajati K Nayak; Jan-e Alam; Tetsufumi Hirano; Sourav Sarkar; Bikash Sinha

2009-02-03T23:59:59.000Z

348

Long-range Cooper pair splitting Enhanced by Supercurrent  

E-Print Network (OSTI)

We investigate crossed Andreev reflection (CAR) in a long-range normal metal-superconductor-normal metal junction, with the superconductor carrying a supercurrent along the junction. The energy splitting of quasiparticles in the superconductor induced by the supercurrent opens an energy window, in which CAR can occur over a distance between two normal leads much larger than the superconducting coherence length, with another nonlocal process of elastic cotunneling being completely quenched. As a result, CAR is significantly enhanced within the energy window, and dominates the nonlocal transport, which can be directly measured by the nonlocal differential conductance. The nonlocal entangled electron pairs generated via inverse CAR may belong to opposite or equal energy levels beyond the tunneling limit, and the total entanglement production rate within a unit bias voltage is solely determined by the CAR probability as $\\mathcal{P}=2(1-A_2)A_2/h$. Our work indicates that a long-range Cooper pair splitter with high efficiency of nonlocal entanglement production can be implemented by simply driving a supercurrent.

Wei Chen; D. N. Shi; D. Y. Xing

2014-08-09T23:59:59.000Z

349

Optical phase and the ionization-dissociation dynamics of excited H{sub 2}  

SciTech Connect

We investigate the influence of optical phase on the dynamics of hydrogen molecules excited to a spectral region with competition between predominantly rotational ionization, and dissociation. We show that an appropriate choice of optical phase changes the relative timing of the ionization and dissociation. Furthermore, the temporal width of the ionization and dissociation fluxes can also be controlled, in a matter-wave analogy of transform-limited optical pulses. The close link between the optical phase and the photoinduced electronic and molecular dynamics has important implications for femtochemistry.

Kirrander, A.; Fielding, H. H. [Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Jungen, Ch. [Laboratoire Aime Cotton du CNRS, Universite de Paris-Sud, 91405 Orsay (France)

2010-01-14T23:59:59.000Z

350

Chemi-ionization in Solar Photosphere: Influence on the Hydrogen Atom excited States Population  

E-Print Network (OSTI)

In this paper, the influence of chemi-ionization processes in $H^*(n \\ge 2) + H(1s)$ collisions, as well as the influence of inverse chemi-recombination processes on hydrogen atom excited-state populations in solar photosphere, are compared with the influence of concurrent electron-atom and electron-ion ionization and recombination processes. It has been found that the considered chemi-ionization/recombination processes dominate over the relevant concurrent processes in almost the whole solar photosphere. Thus, it is shown that these processes and their importance for the non-LTE modeling of the solar atmosphere should be investigated further.

Mihajlov, Anatolij A; Sreckovic, Vladimir A; Dimitrijevic, Milan S; 10.1088/0067-0049/193/1/2

2011-01-01T23:59:59.000Z

351

Design and Prototyping of an Ionization Profile Monitor for the SNS Accumulator Ring  

SciTech Connect

An ionization profile monitor (IPM) has been designed for the Spallation Neutron Source (SNS) accumulator ring. Utilizing ionized electrons produced by beam-gas ionization, the SNS IPM uses a 120 kV bias potential to overcome beam space charge and accelerate electrons towards a movable particle detector. A 300 G magnetic field is used to confine the transverse electron motion, resulting in profile errors at the estimated 7% level. With a system bandwidth of 17.5 MHz. The SNS IPM is capable of measuring turn-by-turn beam profiles for a fully accumulated beam. This paper presents a description of the system and design.

Bartkoski, Dirk A [ORNL; Deibele, Craig E [ORNL; Polsky, Yarom [ORNL

2014-01-01T23:59:59.000Z

352

State recovery and lockstep execution restart in a system with multiprocessor pairing  

DOE Patents (OSTI)

System, method and computer program product for a multiprocessing system to offer selective pairing of processor cores for increased processing reliability. A selective pairing facility is provided that selectively connects, i.e., pairs, multiple microprocessor or processor cores to provide one highly reliable thread (or thread group). Each paired microprocessor or processor cores that provide one highly reliable thread for high-reliability connect with a system components such as a memory "nest" (or memory hierarchy), an optional system controller, and optional interrupt controller, optional I/O or peripheral devices, etc. The memory nest is attached to a selective pairing facility via a switch or a bus. Each selectively paired processor core is includes a transactional execution facility, whereing the system is configured to enable processor rollback to a previous state and reinitialize lockstep execution in order to recover from an incorrect execution when an incorrect execution has been detected by the selective pairing facility.

Gara, Alan; Gschwind, Michael K; Salapura, Valentina

2014-01-21T23:59:59.000Z

353

Density and pair-density scaling for deriving the Euler equation in density-functional and pair-density-functional theory  

SciTech Connect

A link between density and pair density functional theories is presented. Density and pair density scaling are used to derive the Euler equation in both theories. Density scaling provides a constructive way of obtaining approximations for the Pauli potential. The Pauli potential (energy) of the density functional theory is expressed as the difference of the scaled and original exchange-correlation potentials (energies).

Nagy, A. [Department of Theoretical Physics, University of Debrecen, H-4010 Debrecen (Hungary)

2011-09-15T23:59:59.000Z

354

Origin of the ionized wind in MWC 349A  

E-Print Network (OSTI)

The UC-HII region of MWC 349A is the prototype of an ionized wind driven by a massive star surrounded by a disk. Recent high angular resolution observations of the millimeter recombination lines have shown that the disk rotates with a Keplerian law in its outer parts. However, the kinematics of innermost regions in the UC-HII region of MWC 349A is still unknown, in particular the radius where the wind is launched from the disk. We performed hydrogen recombination line observations with the Heterodyne Instrument for the Far Infrared (HIFI) onboard the Herschel Space Observatory to study the kinematics of its innermost regions by studying their spectral features. In addition to the two laser peaks, we report the first detection of two new components that are blueshifted with respect to the laser peaks for all the recombination lines with principal quantum number nwind is ejected from the disk. We used our 3D non-LTE radiative transfer model...

Báez-Rubio, Alejandro; Thum, Clemens; Planesas, Pere; Torres-Redondo, Josefina

2014-01-01T23:59:59.000Z

355

Detecting excess ionizing radiation by electromagnetic breakdown of air  

Science Journals Connector (OSTI)

A scheme is proposed for detecting a concealed source of ionizing radiation by observing the occurrence of breakdown in atmospheric air by an electromagnetic wave whose electric field surpasses the breakdown field in a limited volume. The volume is chosen to be smaller than the reciprocal of the naturally occurring concentration of free electrons. The pulse duration of the electromagnetic wave must exceed the avalanchebreakdown time (10–200 ns) and could profitably be as long as the statistical lag time in ambient air (typically microseconds). Candidate pulsed electromagnetic sources over a wavelength range 3 ? mm > ? > 10.6 ? ? m are evaluated. Suitable candidate sources are found to be a 670 GHz gyrotron oscillator with 200 kW 10 ? ? s output pulses and a Transversely Excited Atmospheric-Pressure (TEA) CO 2 laser with 30 MW 100 ns output pulses. A system based on 670 GHz gyrotron would have superior sensitivity. A system based on the TEA CO 2 laser could have a longer range > 100 ? m .

Victor L. Granatstein; Gregory S. Nusinovich

2010-01-01T23:59:59.000Z

356

Electrospray ionization mass spectrometric characterization of acrylamide adducts to hemoglobin  

SciTech Connect

The most common procedure to identify hemoglobin adducts has been to cleave the adducts from the protein and characterize the adducting species, by, for example, derivatization and gas chromatography/mass spectrometry. To extend these approaches we used electrospray ionization mass spectrometry (ESI-MS) to characterize adducted hemoglobin. For this we incubated [[sup 14]C]acrylamide with the purified human hemoglobin (type A[sub 0]) under conditions that yielded high adduct levels. When the hemoglobin was separated by reversed-phase high-performance liquid chromatography (HPLC), 65% of the radioactivity copurified with the [beta]-subunit. Three adducted species were prominent in the ESI mass spectrum of the intact [beta]-subunit, indicating acrylamide adduction (i.e., mass increase of 71 Da) and two addition unidentified moieties with mass increments of 102 and 135 Da. Endoproteinase Glu-C digestion of the adducted [beta]-subunit resulted in a peptide mixture that, upon reversed-phase HPLC separation, provided several radiolabeled peptides. Using ESI-MS we identified these as the V[sub 91-101] and V[sub 102-122] peptides that represent the cysteine-containing peptides of the [beta]-subunit. These results provide definitive information on acrylamide-modified human hemoglobin and demonstrate that ESI-MS provides valuable structure information on chemically adducted proteins. 30 refs., 9 figs., 3 tabs.

Springer, D.L.; Goheen, S.C.; Edmonds, C.G. (Pacific Northwest Lab., Richland, WA (United States)); Bull, R.J.; Sylvester, D.M. (Washington State Univ., Pullman, WA (United States))

1993-01-01T23:59:59.000Z

357

Moving boundary approximation for curved streamer ionization fronts: Solvability analysis  

Science Journals Connector (OSTI)

The minimal density model for negative streamer ionization fronts is investigated. An earlier moving boundary approximation for this model consisted of a “kinetic undercooling” type boundary condition in a Laplacian growth problem of Hele-Shaw type. Here we derive a curvature correction to the moving boundary approximation that resembles surface tension. The calculation is based on solvability analysis with unconventional features, namely, there are three relevant zero modes of the adjoint operator, one of them diverging; furthermore, the inner-outer matching ahead of the front must be performed on a line rather than on an extended region; and the whole calculation can be performed analytically. The analysis reveals a relation between the fields ahead and behind a slowly evolving curved front, the curvature and the generated conductivity. This relation forces us to give up the ideal conductivity approximation, and we suggest to replace it by a charge neutrality approximation. This implies that the electric potential in the streamer interior is no longer constant but solves a Laplace equation; this leads to a Muskat-type problem.

Fabian Brau, Benny Davidovitch, and Ute Ebert

2008-11-21T23:59:59.000Z

358

Creation, excitation and ionization of a mesoscopic superatom  

E-Print Network (OSTI)

Controlling strongly interacting many-body systems enables the creation of tailored quantum matter, with properties surpassing single particle physics. Atomic ensembles which are optically driven to a Rydberg state provide many examples for this, such as atom-atom entanglement [1,2], many-body Rabi oscillations [3], and strong photon-photon interaction [4]. In its most basic form, Rydberg quantum matter consists of an isolated ensemble of strongly interacting atoms spatially confined to the blockade volume - a so-called superatom. Here, we demonstrate the controlled creation and characterization of an isolated mesoscopic superatom by means of accurate density engineering and excitation to Rydberg p-states. Looking at continuous laser-induced ionization we observe a transition from strongly anti-bunched ion emission under blockade conditions to extremely bunched ion emission under off-resonant excitation. Our experimental setup enables in vivo measurements of the superatom, yielding insight into the excitation statistics and dynamics. We anticipate straightforward applications in quantum optics and quantum information as well as future experiments on many-body physics with superatoms.

T. M. Weber; M. Höning; T. Niederprüm; T. Manthey; O. Thomas; V. Guarrera; M. Fleischhauer; G. Barontini; H. Ott

2014-07-14T23:59:59.000Z

359

Detecting excess ionizing radiation by electromagnetic breakdown of air  

SciTech Connect

A scheme is proposed for detecting a concealed source of ionizing radiation by observing the occurrence of breakdown in atmospheric air by an electromagnetic wave whose electric field surpasses the breakdown field in a limited volume. The volume is chosen to be smaller than the reciprocal of the naturally occurring concentration of free electrons. The pulse duration of the electromagnetic wave must exceed the avalanche breakdown time (10-200 ns) and could profitably be as long as the statistical lag time in ambient air (typically, microseconds). Candidate pulsed electromagnetic sources over a wavelength range, 3 mm>{lambda}>10.6 {mu}m, are evaluated. Suitable candidate sources are found to be a 670 GHz gyrotron oscillator with 200 kW, 10 {mu}s output pulses and a Transversely Excited Atmospheric-Pressure (TEA) CO{sub 2} laser with 30 MW, 100 ns output pulses. A system based on 670 GHz gyrotron would have superior sensitivity. A system based on the TEA CO{sub 2} laser could have a longer range >100 m.

Granatstein, Victor L.; Nusinovich, Gregory S. [Center for Applied Electromagnetics, Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States)

2010-09-15T23:59:59.000Z

360

N=2 Super Boussinesq Hierarchy: Lax Pairs and Conservation Laws  

E-Print Network (OSTI)

We study the integrability properties of the one-parameter family of $N=2$ super Boussinesq equations obtained earlier by two of us (E.I. \\& S.K., Phys. Lett. B 291 (1992) 63) as a hamiltonian flow on the $N=2$ super-$W_3$ algebra. We show that it admits nontrivial higher order conserved quantities and hence gives rise to integrable hierarchies only for three values of the involved parameter, $\\alpha=-2,\\;-1/2,\\;5/2$. We find that for the case $\\alpha = -1/2$ there exists a Lax pair formulation in terms of local $N=2$ pseudo-differential operators, while for $\\alpha = -2$ the associated equation turns out to be bi-hamiltonian.

S. Bellucci; E. Ivanov; S. Krivonos; A. Pichugin

1993-05-18T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

Valley pair qubits in double quantum dots of gapped graphene  

E-Print Network (OSTI)

The rise of graphene opens a new door to qubit implementation, as discussed in the recent proposal of valley pair qubits in double quantum dots of gapped graphene (Wu et al., arXiv: 1104.0443 [cond-mat.mes-hall]). The work here presents the comprehensive theory underlying the proposal. It discusses the interaction of electrons with external magnetic and electric fields in such structures. Specifically, it examines a strong, unique mechanism, i.e., the analogue of the 1st-order relativistic effect in gapped graphene. This mechanism is state mixing free and allows, together with the electrically tunable exchange coupling, a fast, all-electric manipulation of qubits via electric gates, in the time scale of ns. The work also looks into the issue of fault tolerance in a typical case, yielding at 10oK a long qubit coherence time (~O(ms)).

G. Y. Wu; N. -Y. Lue; L. Chang

2011-07-03T23:59:59.000Z

362

Interaction between graphene and metamaterials: split rings vs. wire pairs  

SciTech Connect

We have recently shown that graphene is unsuitable to replace metals in the current-carrying elements of metamaterials. At the other hand, experiments have demonstrated that a layer of graphene can modify the optical response of a metal-based metamaterial. Here we study this electromagnetic interaction between metamaterials and graphene. We show that the weak optical response of graphene can be modified dramatically by coupling to the strong resonant fields in metallic structures. A crucial element determining the interaction strength is the orientation of the resonant fields. If the resonant electric field is predominantly parallel to the graphene sheet (e.g., in a complementary split-ring metamaterial), the metamaterial’s resonance can be strongly damped. If the resonant field is predominantly perpendicular to the graphene sheet (e.g., in a wire-pair metamaterial), no significant interaction exists.

Zou, Yanhong; Tassin, Philippe; Koschny, Thomas; Soukoulis, Costas

2012-05-14T23:59:59.000Z

363

Search for neutralino pair production at the CERN LHC  

E-Print Network (OSTI)

We provide the next-to-leading order (NLO) predictions for the neutralino pair production via quark-antiquark annihilation and gluon-gluon fusion at the CERN Large Hadron Collider, focusing on the lightest neutralino which is likely to be the lightest supersymmetric particle. The dependence of total LO, NLO cross sections, and $K$ factor on the center-of-mass energy, the $M_2$-$\\mu$ mass plane, the squark mass, and the factorization and renormalization scales is comprehensively analyzed for three different scenarios in the minimal supersymmetric standard model and the constrained minimal supersymmetric standard model. We find that the LO cross section is considerably increased by the NLO correction, and the $K$ factor value is clearly related to the Higgsino/gaugino mass parameters, the squark mass, and the factorization and renormalization scales.

Demirci, M

2014-01-01T23:59:59.000Z

364

Search for neutralino pair production at the CERN LHC  

E-Print Network (OSTI)

We provide the next-to-leading order (NLO) predictions for the neutralino pair production via quark-antiquark annihilation and gluon-gluon fusion at the CERN Large Hadron Collider, focusing on the lightest neutralino which is likely to be the lightest supersymmetric particle. The dependence of total LO, NLO cross sections, and $K$ factor on the center-of-mass energy, the $M_2$-$\\mu$ mass plane, the squark mass, and the factorization and renormalization scales is comprehensively analyzed for three different scenarios in the minimal supersymmetric standard model and the constrained minimal supersymmetric standard model. We find that the LO cross section is considerably increased by the NLO correction, and the $K$ factor value is clearly related to the Higgsino/gaugino mass parameters, the squark mass, and the factorization and renormalization scales.

M. Demirci; A. I. Ahmadov

2014-04-02T23:59:59.000Z

365

Discovering the Higgs boson with low mass muon pairs  

Science Journals Connector (OSTI)

Many models of electroweak symmetry breaking have an additional light pseudoscalar. If the Higgs boson can decay to a new pseudoscalar, LEP searches for the Higgs can be significantly altered and the Higgs can be as light as 86 GeV. Discovering the Higgs boson in these models is challenging when the pseudoscalar is lighter than 10 GeV because it decays dominantly into tau leptons. In this paper, we discuss discovering the Higgs in a subdominant decay mode where one of the pseudoscalars decays to a pair of muons. This search allows for potential discovery of a cascade-decaying Higgs boson with the complete Tevatron data set or early data at the LHC.

Mariangela Lisanti and Jay G. Wacker

2009-06-10T23:59:59.000Z

366

Reduction in maximum time uncertainty of paired time signals  

DOE Patents (OSTI)

Reduction in the maximum time uncertainty (t/sub max/ - t/sub min/) of a series of paired time signals t/sub 1/ and t/sub 2/ varying between two input terminals and representative of a series of single events where t/sub 1/ less than or equal to t/sub 2/ and t/sub 1/ + t/sub 2/ equals a constant, is carried out with a circuit utilizing a combination of OR and AND gates as signal selecting means and one or more time delays to increase the minimum value (t/sub min/) of the first signal t/sub 1/ closer to t/sub max/ and thereby reduce the difference. The circuit may utilize a plurality of stages to reduce the uncertainty by factors of 20 to 800.

Theodosiou, G.E.; Dawson, J.W.

1981-02-11T23:59:59.000Z

367

Dynamically tunable Fano resonance in periodically asymmetric graphene nanodisk pair  

E-Print Network (OSTI)

We present a dynamically frequency tunable Fano resonance planar device composed of periodically asymmetric graphene nanodisk pair for the mid-infrared region. There are two kinds of modes in this structure, that is, the symmetric mode and the antisymmetric mode. The resonance coupling between the symmetric and antisymmetric modes creates a classical Fano resonance. Both of the Fano resonance amplitude and frequency of the structure can be dynamically controlled by varying the Fermi energy of graphene. Resonance transition in the structure is studied to reveal the physical mechanism behind the dynamically tunable Fano resonance. The features of the Fano resonant graphene nanostructures should have promising applications in tunable THz filters, switches, and modulators.

Zhang, Zhengren; Fan, Yuancheng; Yin, Pengfei; Zhang, Liwei; Shi, Xi

2015-01-01T23:59:59.000Z

368

Cooper-pair current in the presence of flux noise  

Science Journals Connector (OSTI)

We study the effect of flux noise on the Cooper pair current of a superconducting charge pump. We generalize the definition of the current in order to take into account the contribution induced by the environment. It turns out that this dissipative current vanishes for charge noise but it is finite in general for noise operators that do not commute with the charge operator. We discuss in a generic framework the effect of flux noise and present a way to engineer it by coupling the system to an additional external circuit. We calculate numerically the pumped charge through the device by solving the master equation for the reduced density matrix of the system and show how it depends on the coupling to the artificial environment.

P. Solinas; M. Möttönen; J. Salmilehto; J. P. Pekola

2012-01-20T23:59:59.000Z

369

Enhanced superconducting pairing interaction in indium-doped tin telluride  

SciTech Connect

The ferroelectric degenerate semiconductor Sn{sub 1-{delta}}Te exhibits superconductivity with critical temperatures, T{sub c}, of up to 0.3 K for hole densities of order 10{sup 21} cm{sup -3}. When doped on the tin site with greater than x{sub c} = 1.7(3)% indium atoms, however, superconductivity is observed up to 2 K, though the carrier density does not change significantly. We present specific heat data showing that a stronger pairing interaction is present for x > x{sub c} than for x < x{sub c}. By examining the effect of In dopant atoms on both T{sub c} and the temperature of the ferroelectric structural phase transition, T{sub SPT}, we show that phonon modes related to this transition are not responsible for this T{sub c} enhancement, and discuss a plausible candidate based on the unique properties of the indium impurities.

Erickson, A.S.

2010-05-03T23:59:59.000Z

370

Enhanced superconducting pairing interaction in indium-doped tin telluride  

SciTech Connect

The ferroelectric degenerate semiconductor Sn{sub 1-{delta}}Te exhibits superconductivity with critical temperatures, T{sub c}, of up to 0.3 K for hole densities of order 10{sup 21} cm{sup -3}. When doped on the tin site with greater than x{sub c} = 1.7(3)% indium atoms, however, superconductivity is observed up to 2 K, though the carrier density does not change significantly. We present specific heat data showing that a stronger pairing interaction is present for x > x{sub c} than for x < x{sub c}. By examining the effect of In dopant atoms on both T{sub c} and the temperature of the ferroelectric structural phase transition, T{sub SPT}, we show that phonon modes related to this transition are not responsible for this T{sub c} enhancement, and discuss a plausible candidate based on the unique properties of the indium impurities.

Erickson, A.S.; Chu, J.-H.; /Stanford U., Appl. Phys. Dept. /Stanford U., Geballe Lab.; Toney, M.F.; Geballe, T.H.; Fisher, I.R.; /SLAC, SSRL /Stanford U., Appl. Phys. Dept. /Stanford U., Geballe Lab.

2010-02-15T23:59:59.000Z

371

Neutron And Gamma Detector Using An Ionization Chamber With An Integrated  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron And Gamma Detector Using An Ionization Chamber Neutron And Gamma Detector Using An Ionization Chamber Neutron And Gamma Detector Using An Ionization Chamber With An Integrated Body And Moderator A detector for detecting neutrons and gamma radiation includes a cathode that defines an interior surface and an interior volume. Available for thumbnail of Feynman Center (505) 665-9090 Email Neutron And Gamma Detector Using An Ionization Chamber With An Integrated Body And Moderator A detector for detecting neutrons and gamma radiation includes a cathode that defines an interior surface and an interior volume. A conductive neutron-capturing layer is disposed on the interior surface of the cathode and a plastic housing surrounds the cathode. A plastic lid is attached to the housing and encloses the interior volume of the cathode forming an

372

Electron impact study of ionization and dissociation of monosilane and disilane  

Science Journals Connector (OSTI)

Electron impact study of ionization and dissociation of monosilane and disilane ... Formation Mechanism of Hydrogenated Silicon Clusters during Thermal Decomposition of Disilane ... Formation Mechanism of Hydrogenated Silicon Clusters during Thermal Decomposition of Disilane ...

P. Potzinger; F. W. Lampe

1969-01-01T23:59:59.000Z

373

Ionization Profilometer for an Accumulator-Synchroton with a COSY Cooler  

Science Journals Connector (OSTI)

A profilometer operating on the principle of residual-gas ionization by accelerated particles makes it possible to measure a beam profile without degrading the characteristics of the beam. The coordinates of t...

J. Dietrich; V. Kamerdzhiev

2003-01-01T23:59:59.000Z

374

PP2A regulates ionizing radiation–induced apoptosis through Ser46 phosphorylation of p53  

Science Journals Connector (OSTI)

...Articles PP2A regulates ionizing radiation-induced apoptosis through Ser46...virginia.edu 1 Department of Radiation Oncology and 2 Center for Cell...and Dental University, Tokyo, Japan). Radiation Treatment Cell cultures were irradiated...

Jun Mi; Elzbieta Bolesta; David L. Brautigan; and James M. Larner

2009-01-01T23:59:59.000Z

375

Calicivirus Inactivation by Nonionizing (253.7-Nanometer-Wavelength [UV]) and Ionizing (Gamma) Radiation  

Science Journals Connector (OSTI)

...7-nm-wavelength [UV]) radiation, inactivation by ionizing (gamma) radiation was studied as a process...constituents on inactivation by radiation. MATERIALS AND METHODS Viruses...Shoji Corporation, Tokyo, Japan) was propagated in MDCK...

Ana Maria de Roda Husman; Paul Bijkerk; Willemijn Lodder; Harold van den Berg; Walter Pribil; Alexander Cabaj; Peter Gehringer; Regina Sommer; Erwin Duizer

2004-09-01T23:59:59.000Z

376

High-frequency two-photon ionization of helium and cesium  

Science Journals Connector (OSTI)

Calculations of the two-photon ionization of metastable levels of helium and the first three s levels of cesium are presented. The calculations are carried out to second order in a...

Marinescu, M; Sadeghpour, H R; Dalgarno, A

1993-01-01T23:59:59.000Z

377

Phase space structures and ionization dynamics of hydrogen atom in elliptically polarized microwaves  

E-Print Network (OSTI)

The multiphoton ionization of hydrogen atoms in a strong elliptically polarized microwave field exhibits complex features that are not observed for ionization in circular and linear polarized fields. Experimental data reveal high sensitivity of ionization dynamics to the small changes of the field polarization. The multidimensional nature of the problem makes widely used diagnostics of dynamics, such as Poincar\\'{e} surfaces of section, impractical. We analyze the phase space dynamics using finite time stability analysis rendered by the fast Lyapunov Indicators technique. The concept of zero--velocity surface is used to initialize the calculations and visualize the dynamics. Our analysis provides stability maps calculated for the initial energy at the maximum and below the saddle of the zero-velocity surface. We estimate qualitatively the dependence of ionization thresholds on the parameters of the applied field, such as polarization and scaled amplitude.

Elena Shchekinova; Cristel Chandre; Turgay Uzer

2006-08-24T23:59:59.000Z

378

Double-gated isolated vertically aligned carbon nanofiber field emission and field ionization arrays  

E-Print Network (OSTI)

Electron impact ionization (ElI) is used extensively in mass spectrometry for gas-phase analytes. Due to the significant amount of fragmentation generated by ElI, the spectrum is usually very noisy. In addition, the ...

Chen, Liang-Yu, 1979-

2007-01-01T23:59:59.000Z

379

Reconstruction of ionization probabilities from spatially averaged data in N dimensions  

E-Print Network (OSTI)

We present an analytical inversion technique, which can be used to recover ionization probabilities from spatially averaged data in an N-dimensional detection scheme. The solution is given as a power series in intensity. For this reason, we call...

Stroahaber, James; Kolomenskii, A; Schuessler, Hans

2010-07-06T23:59:59.000Z

380

extremely low-dose ionizing radiation upregulates CXC chemokines in normal human fibroblasts  

Science Journals Connector (OSTI)

...2006 Abstract Tumor Biology 32: Radiation Biology 2 Proc Amer Assoc Cancer...Volume 47, 2006 extremely low-dose ionizing radiation upregulates CXC chemokines in...biological effects of this low dose range have not been established. We...

Akira Fujimori; Katsutoshi Suetomi; Keiji Kinoshita; Ayako Kojima; Yaqun Fang; Ayako Egusa; and Ryuichi Okayasu

2006-04-15T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

Polymorphisms in DNA Repair Genes, Medical Exposure to Ionizing Radiation, and Breast Cancer Risk  

Science Journals Connector (OSTI)

...the role of DSB repair in response to low-dose radiation, particularly the range experienced by women from mammograms and other...breast cancer associated with exposure to low doses of ionizing radiation. Although we specifically designed our questionnaire...

Robert C. Millikan; Jon S. Player; Allan Rene deCotret; Chiu-Kit Tse; and Temitope Keku

2005-10-01T23:59:59.000Z

382

E-Print Network 3.0 - astrophysical ionizing radiation Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

Perturbations and level splittings 8-3 Ionization and the Saha equation 2. Textbook Radiative processes... the following chapters: Chapter 1 Basic concepts 1-1 Radiative flux and...

383

g-Hartree ab initio calculation of ionization energies of Ca (Z=20)  

Science Journals Connector (OSTI)

The main atomic ionization energies of Ca (Z=20) are calculated by the g-Hartree method. The agreement between theory and experiment is excellent. A detailed comparison of present method with other approximation schemes is made.

Masahide Ohno

1987-04-15T23:59:59.000Z

384

High Resolution Particle Beam Monitoring and Ionization Counters with the Help of Single Carbon Nanotubes  

E-Print Network (OSTI)

After a short review of modern beam monitors, ionization and proportional counters and discussion on the necessity to have thinner wires, we propose and consider construction and parameters of nanotube particle beam monitors and counters

K. A. Ispirian; R. K. Ispiryan; A. T. Margarian

2009-08-18T23:59:59.000Z

385

Single and double ionization of helium within the independent event model  

E-Print Network (OSTI)

A single centered expansion with a finite Hilbert basis set has been used to calculate the electron removal probabilities for He+ and He by antiproton and proton projectiles. Single and double ionization cross sections of He are calculated under...

Wehrman, Laurence Allan

2012-06-07T23:59:59.000Z

386

Quasi-16-day periodic meridional movement of the equatorial ionization anomaly  

E-Print Network (OSTI)

Based on the daytime location of the equatorial ionization anomaly (EIA) crest derived from GPS observations at low latitude over China during the 2005–2006 stratospheric sudden warming (SSW), a quasi-16-day periodic ...

Mo, X. H.

387

Ionization behavior of molecular hydrogen in intense laser fields: Influence of molecular vibration and alignment  

E-Print Network (OSTI)

The alignment- and internuclear-distance dependent ionization of H$_2$ exposed to intense, ultrashort laser fields is studied by solving the time-dependent two-electron Schr\\"odinger equation. In the regime of perturbative few-photon ionization, a strong dependence of the ionization yield on the internuclear distance is found. While this finding confirms a previously reported breakdown of the fixed-nuclei approximation for parallel alignment, a simpler explanation is provided and it is demonstrated that this breakdown is not due to vibrational dynamics during the laser pulse. The persistence of this effect even for randomly aligned molecules is demonstrated. Furthermore, the transition from the multiphoton to the quasi-static (tunneling) regime is investigated considering intense 800 nm laser pulses. While the obtained ionization yields differ significantly from the prediction of Ammosov-Delone-Krainov rates, we find a surprisingly good quantitative agreement after introducing a simple frequency-dependent cor...

Förster, Johann; Saenz, Alejandro

2014-01-01T23:59:59.000Z

388

In situ transmission electron microscopy observation of silver oxidation in ionized/atomic gas.  

SciTech Connect

The interaction between silver and ionized and atomic gas was observed directly by in situ transmission electron microscopy with an environmental cell for the first time. The electron beam provides dual functions as the source of both gas ionization and imaging. The concentration of ionized gas was tuned via adjusting the current density of the electron beam. Oxidation of the silver is observed in situ, indicating the presence of ionized and/or atomic oxygen. The evolution of microstructure and phase constituents was characterized. Then the oxidation rate was measured, and the relationships among grain size, mass transport rate, and electron flux were characterized. The role of the electron beam is discussed, and the results are rationalized with respect to ex situ results from the literature.

Sun, L.; Noh, K. W.; Wen, J-G.; Dillon, S. J. (Materials Science Division); (Massachusetts Inst. Tech.); (Univ. Illinois - Urbana)

2011-10-17T23:59:59.000Z

389

Fundamentals and Applications of Electrospray Ionization Mass Spectrometry for Petroleum Characterization  

Science Journals Connector (OSTI)

Fundamentals and Applications of Electrospray Ionization Mass Spectrometry for Petroleum Characterization ... We are reporting a study of the fundamental and application aspects of positive-ion electrospray ionization (ESI+) for petroleum characterization. ... The gas-phase basicities (GBs) were experimental data from the NIST Chemistry WebBook,33 whereas the aqueous basicities (pKb) were derived from Lange's Handbook of Chemistry, 14th Edition. ...

Kuangnan Qian; Kathleen E. Edwards; John H. Diehl; Larry A. Green

2004-09-10T23:59:59.000Z

390

Intensity-resolved Above Threshold Ionization Yields of Atoms with Ultrashort Laser Pulses  

E-Print Network (OSTI)

. Electron ionization yields of xenon were measured for a set of laser pulse intensities using a time of flight (TOF) setup. Horizontally polarized, unchirped, pulses were used in the ionization process. All laser parameters other than the radiation... Tiezer, I am grateful for all their time and help. I would like to thank Dr. James Strohaber for detailed discussions and assistance related to this experiment. I acknowledge the Department of Physics at Texas A&M and the US Air Force...

Hart, Nathan Andrew

2012-10-19T23:59:59.000Z

391

The Cryogenic Dark Matter Search: First 5-Tower Data and Improved Understanding of Ionization Collection  

SciTech Connect

The Cryogenic Dark Matter Search (CDMS) is searching for Weakly Interacting Massive Particles (WIMPs) with cryogenic particle detectors. These detectors have the ability to discriminate between nuclear recoil candidate and electron recoil background events by collecting both phonon and ionization energy from recoils in the detector crystals. The CDMS-II experiment has completed analysis of the first data runs with 30 semiconductor detectors at the Soudan Underground Laboratory, resulting in a world leading WIMP-nucleon spin-independent cross section limit for WIMP masses above 44 GeV/c{sup 2}. As CDMS aims to achieve greater WIMP sensitivity, it is necessary to increase the detector mass and discrimination between signal and background events. Incomplete ionization collection results in the largest background in the CDMS detectors as this causes electron recoil background interactions to appear as false candidate events. Two primary causes of incomplete ionization collection are surface and bulk trapping. Recent work has been focused on reducing surface trapping through the modification of fabrication methods for future detectors. Analyzing data taken with test devices has shown that hydrogen passivation of the amorphous silicon blocking layer worsens surface trapping. Additional data has shown that the iron-ion implantation used to lower the critical temperature of the tungsten transition-edge sensors causes a degradation of the ionization collection. Using selective implantation on future detectors may improve ionization collection for events near the phonon side detector surface. Bulk trapping is minimized by neutralizing ionized lattice impurities. Detector investigations at testing facilities and in situ at the experimental site have provided methods to optimize the neutralization process and monitor running conditions to maintain full ionization collection. This work details my contribution to the 5-tower data taking, monitoring, and analysis effort as well as the SuperCDMS detector development with the focus on monitoring and improving ionization collection in the detectors.

Bailey, Catherine N.; /Case Western Reserve U.

2010-01-01T23:59:59.000Z

392

MMTF DISCOVERY OF GIANT IONIZATION CONES IN MR 2251-178: IMPLICATIONS FOR QUASAR RADIATIVE FEEDBACK  

SciTech Connect

We report the discovery of giant ionization cones in the 140 kpc nebula around quasar MR 2251-178 based on deep [O III] {lambda}5007/H{beta} and [N II] {lambda}6583/H{alpha} flux ratio maps obtained with the Maryland-Magellan Tunable Filter on the Baade-Magellan 6.5 m Telescope. These cones are aligned with the weak double-lobed radio source observed on smaller scale (<30 kpc). They have an opening angle {approx}120 Degree-Sign {+-} 10 Degree-Sign and subtend {approx}65%-90% of 4{pi} sr, where the uncertainty takes into account possible projection effects. The material in the outer ionization cones is matter-bounded, indicating that all ionizing photons emitted through the cones escape from the system. The quasar ionizing flux is {approx}2-3 times fainter outside of these cones, despite the largely symmetric geometry of the nebula in [O III]. Overall, adding up the contributions from both inside and outside the cones, we find that {approx}65%-95% of the quasar ionizing radiation makes its way out of the system. These results emphasize the need for line ratio maps to quantify the escape fraction of ionizing radiation from quasars and the importance of quasar radiative feedback on the intergalactic medium.

Kreimeyer, Kory; Veilleux, Sylvain, E-mail: kory@astro.umd.edu, E-mail: veilleux@astro.umd.edu [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)

2013-07-20T23:59:59.000Z

393

Re-Ionization and its Imprint on the Cosmic Microwave Background  

E-Print Network (OSTI)

Early reionization changes the pattern of anisotropies expected in the cosmic microwave background. To explore these changes, we derive from first principles the equations governing anisotropies, focusing on the interactions of photons with electrons. Vishniac (1987) claimed that second order terms can be large in a re-ionized Universe, so we derive equations correct to second order in the perturbations. There are many more second order terms than were considered by Vishniac. To understand the basic physics involved, we present a simple analytic approximation to the first order equation. Then turning to the sec- ond order equation, we show that the Vishniac term is indeed the only important one. We also present numerical results for a variety of ionization histories [in a standard cold dark matter Universe] and show quantitatively how the sig- nal in several experiments depends on the ionization history. The most pronounced indication of a re-ionized Universe would be seen in very small scale experiments; the expected signal in the Owens Valley experiment is smaller by a factor of order ten if the last scattering surface is at a redshift $z\\simeq100$ as it would be if the Universe were re-ionized very early. On slightly larger scales, the expected signal in a re-ionized Universe {\\it is} smaller than it would be with standard recombination, but only by a factor of two or so.

Scott Dodelson; Jay Jubas

1993-08-16T23:59:59.000Z

394

Calculation of ionization balance and electrical conductivity in nonideal aluminum plasma  

Science Journals Connector (OSTI)

A practical approach has been implemented to calculate the ionization balance and electrical conductivity of warm dense aluminum plasma with the Coulomb coupling effect taken into account. The correction term for ionization potential is formulated with a number of basic dimensionless parameters that characterize nonideal plasma and incorporated with the fitted formulas of excess free energy given by Tanaka, Mitake, and Ichimaru [Phys. Rev. A 32, 1896 (1985)] and Chabrier and Potekhin [Phys. Rev. E 58, 4941 (1998)] to determine the ionization balance in an equilibrium state. The calculated degree of ionization of aluminum plasma exhibits a sudden increase near the solid density ?1 g/cm3 at temperatures of a few eV, which effectively demonstrates the pressure-induced ionization. The electrical conductivity is evaluated in a partially ionized plasma regime based on a linear mixture rule that takes into account both the electron-ion and electron-neutral collisions and then the computed results are compared with available data from recent experiments. It is shown that the calculation well reproduces the overall trend of measured electrical conductivity of nonideal aluminum plasma accounting for the metal-insulator transition.

Deok-Kyu Kim and Inho Kim

2003-11-25T23:59:59.000Z

395

Ionizing radiation and atherosclerosis: Current knowledge and future challenges  

Science Journals Connector (OSTI)

Abstract The evaluation of the health effects of low-dose ionizing radiation has always been a focus of debate and investigation within the scientific community. During the last decade, epidemiological studies provided evidence that an excess risk of cardiovascular diseases (CVDs) can be associated with moderate and low dose radiation. The precise quantification of CVD risk in the low-dose radiation range (dose below which there is no risk. A limited number of studies with imaging surrogate endpoints and cardiovascular biomarkers in asymptomatic patients revealed early signs of cardiovascular alterations, even at a low dose. In vitro studies have shown that several mechanisms, including endothelial dysfunction, inflammation, oxidative stress, alterations of coagulation and platelet activity may have a relevant role in radiation-induced cardiovascular effects. Exposure to high-dose data in experimental models accelerates the development of atherosclerosis, predisposing to the formation of an inflammatory, thrombotic plaque phenotype, especially in animals that are genetically predisposed to this disease. On the contrary, low dose exposure produced both protective and detrimental effects, suggesting that multiple mechanisms may influence radiation-induced atherosclerosis. However, only very limited and specific information can be obtained from cell cultures and animal models. Planned studies of radiation-exposed cohorts need to be conducted to explore biological mechanisms of low-dose radiation-associated cardiovascular disease. Further investigations with functional imaging to assess vascular function and cardiovascular biomarkers have great potential for providing new insights into low-dose radiation cardiovascular risk, especially in occupational exposure and modern medicine.

Andrea Borghini; Emilio Antonio Luca Gianicolo; Eugenio Picano; Maria Grazia Andreassi

2013-01-01T23:59:59.000Z

396

Effective density dependent pairing forces in the T=1 and T=0 channels  

E-Print Network (OSTI)

Effective density dependent pairing forces of zero range are adjusted on gap values in T=0,1 channels calculated with the Paris force in symmetric nuclear matter. General discussions on the pairing force are presented. In conjunction with the effective k-mass the nuclear pairing force seems to need very little renormalization in the T=1 channel. The situation in the T=0 channel is also discussed.

Garrido, E; Moya de Guerra, E; Schuck, P

1999-01-01T23:59:59.000Z

397

Vaporization of color-singlet pairs from a quark-gluon plasma  

Science Journals Connector (OSTI)

We consider the hadronization of a QCD plasma by diffusion of quark-antiquark pairs through the plasma's surface. We apply the principle of detailed balance to argue that the surface is readily penetrable by color-singlet pairs. The resulting blackbody surface brightness exceeds that of other hadronization mechanisms. We note that the volume increase, needed to accommodate the plasma's high entropy in the dilute hadronic phase, compensates most of the combinatoric and statistical factors needed to select such pairs from the plasma. We conclude that the rate of evaporation of preformed pairs is ample to maintain phase equilibrium with a freely expanding meson gas outside the plasma.

Axel P. Vischer; Jitendra C. Parikh; Philip J. Siemens

1991-01-01T23:59:59.000Z

398

Natural orbits of atomic Cooper pairs in a nonuniform Fermi gas  

E-Print Network (OSTI)

We examine the basic mode structure of atomic Cooper pairs in an inhomogeneous Fermi gas. Based on the properties of Bogoliubov quasi-particle vacuum, the single particle density matrix and the anomalous density matrix share the same set of eigenfunctions. These eigenfunctions correspond to natural pairing orbits associated with the BCS ground state. We investigate these orbits for a Fermi gas in a spherical harmonic trap, and construct the wave function of a Cooper pair in the form of Schmidt decomposition. The issue of spatial quantum entanglement between constituent atoms in a pair is addressed.

Y. H. Pong; C. K. Law

2006-05-08T23:59:59.000Z

399

E-Print Network 3.0 - adolescent twin pairs Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

Sample search results for: adolescent twin pairs Page: << < 1 2 3 4 5 > >> 1 Genes, Brain and Behavior (2009) 8: 107113 2009 The Authors Journal compilation 2009 Blackwell...

400

E-Print Network 3.0 - affected sib-pair families Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

pairs into two diagnostic categories: "narrow" when both affected sibs had autism, and "broad... the distribution of affected ... Source: Ecole Polytechnique, Centre de...

Note: This page contains sample records for the topic "ionization brems pair" 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

Dynamics of iron-acceptor-pair formation in co-doped silicon  

SciTech Connect

The pairing dynamics of interstitial iron and dopants in silicon co-doped with phosphorous and several acceptor types are presented. The classical picture of iron-acceptor pairing dynamics is expanded to include the thermalization of iron between different dopants. The thermalization is quantitatively described using Boltzmann statistics and different iron-acceptor binding energies. The proper understanding of the pairing dynamics of iron in co-doped silicon will provide additional information on the electronic properties of iron-acceptor pairs and may become an analytical method to quantify and differentiate acceptors in co-doped silicon.

Bartel, T.; Gibaja, F.; Graf, O.; Gross, D.; Kaes, M.; Heuer, M.; Kirscht, F. [Calisolar GmbH, Magnusstrasse 11, 12489 Berlin (Germany)] [Calisolar GmbH, Magnusstrasse 11, 12489 Berlin (Germany); Möller, C. [CiS Forschungsinstitut für Mikrosensorik und Photovoltaik GmbH, Konrad-Zuse-Str. 14, 99099 Erfurt (Germany) [CiS Forschungsinstitut für Mikrosensorik und Photovoltaik GmbH, Konrad-Zuse-Str. 14, 99099 Erfurt (Germany); TU Ilmenau, Institut für Physik, Weimarer Str. 32, 98693 Ilmenau (Germany); Lauer, K. [CiS Forschungsinstitut für Mikrosensorik und Photovoltaik GmbH, Konrad-Zuse-Str. 14, 99099 Erfurt (Germany)] [CiS Forschungsinstitut für Mikrosensorik und Photovoltaik GmbH, Konrad-Zuse-Str. 14, 99099 Erfurt (Germany)

2013-11-11T23:59:59.000Z

402

Final state interactions at the threshold of Higgs boson pair production  

E-Print Network (OSTI)

We study the effect of final state interactions at the threshold of Higgs boson pair production in the Glashow-Weinberg-Salam model. We consider three major processes of the pair production in the model: lepton pair annihilation, ZZ fusion, and WW fusion. We find that the corrections caused by the effect for these processes are markedly different. According to our results, the effect can cause non-negligible corrections to the cross sections for lepton pair annihilation and small corrections for ZZ fusion, and this effect is negligible for WW fusion.

Zhang, Zhentao

2015-01-01T23:59:59.000Z

403

NON-EQUILIBRIUM IONIZATION MODELING OF THE CURRENT SHEET IN A SIMULATED SOLAR ERUPTION  

SciTech Connect

The current sheet that extends from the top of flare loops and connects to an associated flux rope is a common structure in models of coronal mass ejections (CMEs). To understand the observational properties of CME current sheets, we generated predictions from a flare/CME model to be compared with observations. We use a simulation of a large-scale CME current sheet previously reported by Reeves et al. This simulation includes ohmic and coronal heating, thermal conduction, and radiative cooling in the energy equation. Using the results of this simulation, we perform time-dependent ionization calculations of the flow in a CME current sheet and construct two-dimensional spatial distributions of ionic charge states for multiple chemical elements. We use the filter responses from the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory and the predicted intensities of emission lines to compute the count rates for each of the AIA bands. The results show differences in the emission line intensities between equilibrium and non-equilibrium ionization. The current sheet plasma is underionized at low heights and overionized at large heights. At low heights in the current sheet, the intensities of the AIA 94 A and 131 A channels are lower for non-equilibrium ionization than for equilibrium ionization. At large heights, these intensities are higher for non-equilibrium ionization than for equilibrium ionization inside the current sheet. The assumption of ionization equilibrium would lead to a significant underestimate of the temperature low in the current sheet and overestimate at larger heights. We also calculate the intensities of ultraviolet lines and predict emission features to be compared with events from the Ultraviolet Coronagraph Spectrometer on the Solar and Heliospheric Observatory, including a low-intensity region around the current sheet corresponding to this model.

Shen Chengcai; Reeves, Katharine K.; Raymond, John C.; Murphy, Nicholas A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ko, Yuan-Kuen [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Lin Jun [Yunnan Astronomical Observatory, Chinese Academy of Sciences, P. O. Box 110, Kunming, Yunnan 650011 (China); Mikic, Zoran; Linker, Jon A. [Predictive Science, Inc. (PSI), San Diego, CA 92121-2910 (United States)

2013-08-20T23:59:59.000Z

404

Massive-muon-pair production at high energy  

Science Journals Connector (OSTI)

A detailed analysis of the inclusive massive-?-pair production process in high-energy proton-proton collisions is presented based on the combined assumptions of light-cone (LC) expansions and multi-Regge theory. The scaling limit is LC dominated and the assumed strongly convergent Regge theory leads to dominance by the leading LC singularities. The resulting amplitude is expressed as a sum of two distinct contributions, a "pionization" piece, which dominates at large dimuon mass M, and a "fragmentation" piece, which dominates at smaller M. The result of the combination of these two contributions, each of fast decrease in M, can produce a shoulder in the d ?dM cross section, as seems to be present experimentally. This requires a small, perhaps vanishing, Pomeron-particle-Pomeron coupling at t=0. A phenomenological model, which simply incorporates the derived behaviors of the scattering amplitude, is introduced to fit the data quantitatively. A good fit to the d ?dM data (at fixed energy) fixes the (five) parameters. The model then is compared with the experimental curves for the transverse and longitudinal dimuon cross sections and the total (energy-dependent) cross section. Good agreement is found. A comparison with the parton model is also given.

R. A. Brandt, A. Kaufman, and G. Preparata

1974-07-01T23:59:59.000Z

405

Emission of Microwave Photon Pairs by a Tunnel Junction  

E-Print Network (OSTI)

Generation and control of non-classical electromagnetic fields is of crucial importance for quantum information physics. While usual methods for the production of such fields rely on a non-linearity (of a crystal, a Josephson junction, etc.), a recent experiment performed on a normal conductor, a tunnel junction under microwave irradiation, has unveiled an alternative: the use of electron shot noise in a quantum conductor\\cite{PAN_squeezing}. Here we show that such a device can emit \\emph{pairs of microwave photons} of different frequencies with a rate as high as that of superconducting Josephson junctions\\cite{Flurin}. This results in intensity fluctuations of the photon field at two different frequencies being correlated below the photon shot noise,i.e. two-mode amplitude squeezing. Our experiment constitutes a fundamental step towards the understanding of electronic noise in terms of quantum optics, and shows that even a normal conductor could be used as a resource for quantum information processing.

Jean-Charles Forgues; Christian Lupien; Bertrand Reulet

2014-03-21T23:59:59.000Z

406

The Detectability of Pair-Production Supernovae at z < 6  

E-Print Network (OSTI)

Nonrotating, zero metallicity stars with initial masses 140 production supernovae (PPSNe), in which an electron-positron pair-production instability triggers explosive nuclear burning. Interest in such stars has been rekindled by recent theoretical studies that suggest primordial molecular clouds preferentially form stars with these masses. Since metal enrichment is a local process, the resulting PPSNe could occur over a broad range of redshifts, in pockets of metal-free gas. Using the implicit hydrodynamics code KEPLER, we have calculated a set of PPSN light curves that addresses the theoretical uncertainties and allows us to assess observational strategies for finding these objects at intermediate redshifts. The peak luminosities of typical PPSNe are only slightly greater than those of Type Ia, but they remain bright much longer (~ 1 year) and have hydrogen lines. Ongoing supernova searches may soon be able to limit the contribution of these very massive stars to < 1% of the total star formation rate density out to z=2 which already provides useful constraints for theoretical models. The planned Joint Dark Energy Mission satellite will be able to extend these limits out to z=6.

Evan Scannapieco; Piero Madau; Stan Woosley; Alexander Heger; Andrea Ferrara

2005-07-08T23:59:59.000Z

407

Pair-production multiplicities in rotation-powered pulsars  

E-Print Network (OSTI)

We discuss the creation of electron-positron cascades in the context of pulsar polar cap acceleration models and derive several useful analytic and semi-analytic results for the spatial extent and energy response of the cascade. Instead of Monte Carlo simulations, we use an integro- differential equation which describes the development of the cascade energy spectrum in one space dimension quite well, when it is compared to existing Monte Carlo models. We reduce this full equation to a single integral equation, from which we can derive useful results, such as the energy loss between successive generations of photons and the spectral index of the response. We find that a simple analytic formula represents the pair cascade multiplicity quite well, provided that the magnetic field is below 10^12 Gauss, and that an only slightly more complex formula matches the numerically-calculated cascade at all other field strengths. Using these results, we find that cascades triggered by gamma rays emitted through inverse Compton scattering of thermal photons from the neutron star's surface, both resonant and non-resonant, are important for the dynamics of the polar cap region in many pulsars.

J. A. Hibschman; J. Arons

2001-07-11T23:59:59.000Z

408

Lateral distribution of muon pairs in deep underground muon showers  

Science Journals Connector (OSTI)

The lateral distribution of muon showers deep underground in the Utah muon detector has been studied. The results are presented in the form of a decoherence curve, which is defined to be the rate of pairs of coincident muons in two small detectors (as a function of their separation) divided by the product of the areas of the detectors. Rates are measured for separations from 1 to greater than 60 m for depths ranging from 2.4 × 105 gcm-2 to 5.6 × 105 gcm-2 and zenith angles ranging from 42.5 to 62.5 degrees. Significant improvements on previously reported data have been made due to increased detector-memory size, improved triggering efficiency, longer running time and better statistical analysis. When the decoherence curve is parameterized by the function R(x)=R0e-xx0 the value of the mean separation x0 at 47.5°, 2.4 × 105 gcm-2 is 11.21 ± 0.38 m. In a modified scaling model this separation suggests an average transverse momentum of roughly 0.65 GeV/c for muons from hadron-air collisions with energy > 10 TeV.

G. H. Lowe; H. E. Bergeson; J. W. Keuffel; M. O. Larson; J. L. Morrison; W. J. West

1976-06-01T23:59:59.000Z

409

Top Quark Properties from Top Pair Events and Decays  

SciTech Connect

Over a decade since the discovery of the top quark we are still trying to unravel mysteries of the heaviest observed particle and learn more about its nature. The continuously accumulating statistics of CDF and DO data provide the means for measuring top quark properties with ever greater precision and the opportunity to search for signs of new physics that could be manifested through subtle deviations from the standard model in the production and decays of top quarks. In the following we present a slice of the rich program in top quark physics at the Fermilab Tevatron: measurements of the properties of top quark decays and searches for unusual phenomena in events with pair produced tops. In particular, we discuss the most recent and precise CDF and DO measurements of the transverse polarization of W bosons from top decays, branching ratios and searches for flavor-changing neutral current decays, decays into charged Higgs and invisible decays. These analyses correspond to integrated luminosities ranging from 0.9 to 2.7 fb{sup -1}.

Ivanov, A.; /UC, Davis

2008-11-01T23:59:59.000Z

410

Two-Dimensional Simulations of Pulsational Pair-Instability Supernovae  

E-Print Network (OSTI)

Massive stars that end their lives with helium cores in the range of 35 to 65 Msun are known to produce repeated thermonuclear outbursts due to a recurring pair-instability. In some of these events, solar masses of material are ejected in repeated outbursts of several times 10$^{50}$ erg each. Collisions between these shells can sometimes produce very luminous transients that are visible from the edge of the observable universe. Previous 1D studies of these events produce thin, high-density shells as one ejection plows into another. Here, in the first multidimensional simulations of these collisions, we show that the development of a Rayleigh-Taylor instability truncates the growth of the high density spike and drives mixing between the shells. The progenitor is a 110 Msun solar-metallicity star that was shown in earlier work to produce a superluminous supernova. The light curve of this more realistic model has a peak luminosity and duration that are similar to those of 1D models but a structure that is smoot...

Chen, Ke-Jung; Heger, Alexander; Almgren, Ann; Whalen, Daniel

2014-01-01T23:59:59.000Z

411

Monte Carlo wave packet approach to dissociative multiple ionization in diatomic molecules  

SciTech Connect

A detailed description of the Monte Carlo wave packet technique applied to dissociative multiple ionization of diatomic molecules in short intense laser pulses is presented. The Monte Carlo wave packet technique relies on the Born-Oppenheimer separation of electronic and nuclear dynamics and provides a consistent theoretical framework for treating simultaneously both ionization and dissociation. By simulating the detection of continuum electrons and collapsing the system onto either the neutral, singly ionized or doubly ionized states in every time step the nuclear dynamics can be solved separately for each molecular charge state. Our model circumvents the solution of a multiparticle Schroedinger equation and makes it possible to extract the kinetic energy release spectrum via the Coulomb explosion channel as well as the physical origin of the different structures in the spectrum. The computational effort is restricted and the model is applicable to any molecular system where electronic Born-Oppenheimer curves, dipole moment functions, and ionization rates as a function of nuclear coordinates can be determined.

Leth, Henriette Astrup; Madsen, Lars Bojer; Moelmer, Klaus [Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)

2010-05-15T23:59:59.000Z

412

The Photo-Ionization of the Vapors of Caesium and Rubidium  

Science Journals Connector (OSTI)

A modification of Foote and Mohler's space charge method for the measurement of photo-ionization was devised which compensated out spurious effects due to fluctuations of temperature and increased the useful sensitivity of the space charge to positive ions about one hundred fold. By measuring simultaneously photo-ionization and light intensities the following results have been obtained. In caesium, the ionization per unit light intensity B? varies with frequency ? (over the range 2200A to 3130A) according to the equation B?=const?3(?-?0) This relation also represents fairly well the experimental observations of B? in rubidium. Thus, the continuous absorption resulting in ionization decreases with wave-length much more rapidly than the analagous absorption beyond the Lyman and Balmer series limits as calculated on the wave mechanics by Sugiura, Oppenheimer, and Reiche. The results, moreover, are not even qualitatively similar to Hargreaves' calculation of the variation with frequency of B? for lithium. Assuming the principle of detailed balance it follows from these experiments that the effective collision capture cross-sections of caesium and rubidium ions for electrons vary inversely as the square of the energy of the electrons relative to the ions. This is the Thomson recombination law and has been derived on the wave mechanics by Oppenheimer for the recombination of protons and electrons. The existence of photo-ionization by absorption of principal series lines in caesium, so clearly exhibited by Mohler, Foote and Chenault, has been confirmed and also has been observed in rubidium.

Ernest O. Lawrence and N. E. Edlefsen

1929-07-15T23:59:59.000Z

413

Investigating Enhanced Thorium Ionization in TIMS Using Re/Pt Porous Ion Emitters  

SciTech Connect

Thermal ionization mass spectrometry (TIMS) is a widely used, benchmark method in the isotopic analysis of actinides relevant to various nuclear and geological fields. Despite significant previous use and inherent advantages, however, poor sample ionization continues to hamper the use of TIMS in the measurement of trace species; actinide ionization efficiencies frequently fall below 0.1 % using traditional instrument sources. Factors leading to poor ionization are compounded in the measurement of several highly refractory metals (e.g. U and Th) that may provide key signatures data in non-proliferation, safeguards and forensics efforts. Herein, a relatively new TIMS ion source strategy, employing porous ion emitters (PIEs) atop traditional filament assemblies, is investigated for the first time as a straightforward means of enhancing the ionization of Th, which is arguably a worst case scenario for TIMS-based actinide measurements. These sources yielded up to 410% greater Th sample utilization, relative to previously published values and in-house measurements collected using traditional methods. Accompanying scanning electron microscopy (SEM) investigations provide preliminary insight into possible mechanisms of PIE functioning and explore the impacts that extended heating have on the constructed source’s structure and composition.

Floyd E. Stanley III; K. J. Spencer; D. S. Schwartz; M. G. Watrous; J. E. Delmore

2014-03-01T23:59:59.000Z

414

Auger spectrum of a water molecule after single and double core ionization  

SciTech Connect

The high intensity of free electron lasers opens up the possibility to perform single-shot molecule scattering experiments. However, even for small molecules, radiation damage induced by absorption of high intense x-ray radiation is not yet fully understood. One of the striking effects which occurs under intense x-ray illumination is the creation of double core ionized molecules in considerable quantity. To provide insight into this process, we have studied the dynamics of water molecules in single and double core ionized states by means of electronic transition rate calculations and ab initio molecular dynamics (MD) simulations. From the MD trajectories, photoionization and Auger transition rates were computed based on electronic continuum wavefunctions obtained by explicit integration of the coupled radial Schroedinger equations. These rates served to solve the master equations for the populations of the relevant electronic states. To account for the nuclear dynamics during the core hole lifetime, the calculated electron emission spectra for different molecular geometries were incoherently accumulated according to the obtained time-dependent populations, thus neglecting possible interference effects between different decay pathways. We find that, in contrast to the single core ionized water molecule, the nuclear dynamics for the double core ionized water molecule during the core hole lifetime leaves a clear fingerprint in the resulting electron emission spectra. The lifetime of the double core ionized water was found to be significantly shorter than half of the single core hole lifetime.

Inhester, L.; Burmeister, C. F.; Groenhof, G.; Grubmueller, H. [Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Goettingen (Germany)

2012-04-14T23:59:59.000Z

415

A CLUSTER PAIR: A3532 AND A3530  

SciTech Connect

We present a detailed study of a close pair of clusters of galaxies, A3532 and A3530, and their environments. The Chandra X-ray image of A3532 reveals the presence of substructures on scales of {approx}20'' in its core. XMM-Newton maps of the clusters show excess X-ray emission from an overlapping region between them. Spectrally determined projected temperature and entropy maps do not show any signs of cluster scale mergers either in the overlapping region or in any of the clusters. In A3532, however, some signs of the presence of galaxy scale mergers are visible, e.g., anisotropic temperature variations in the projected thermodynamic maps, a wide-angle-tailed (WAT) radio source in the brighter nucleus of its dumbbell brightest cluster galaxy, and a candidate X-ray cavity coincident with the northwestern extension of the WAT source in the low-frequency radio observations. The northwestern extension in A3532 seems either a part of the WAT or an unrelated diffuse source in A3532 or in the background. There is an indication that the cool core in A3532 has been disrupted by the central activity of the galactic nucleus. A reanalysis of the redshift data reinforces the close proximity of the clusters. The excess emission in the overlapping region appears to be a result of tidal interactions as the two clusters approach each other for the first time. However, we cannot rule out the possibility of the excess being due to the chance superposition of their X-ray halos.

Lakhchaura, Kiran; Singh, K. P. [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India)] [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India); Saikia, D. J. [National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune University Campus, Pune 411 007 (India)] [National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune University Campus, Pune 411 007 (India); Hunstead, R. W., E-mail: kiran_astro@tifr.res.in [Sydney Institute for Astronomy, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia)

2013-04-10T23:59:59.000Z

416

Resonance tunneling of cooper pairs in a superconductor-polymer-superconductor josephson junction  

SciTech Connect

It is shown that the superconducting current flowing though a polymer in a superconductor-polymer-superconductor Josephson structure is due to resonant tunneling of Cooper pairs. The critical current and the thickness of the polymer in which the superconducting current is observed depend on the coherence length of a Cooper pair in the superconductor contacting the polymer.

Ionov, A. I., E-mail: ionov@tuch.ioffe.ru [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)

2013-05-15T23:59:59.000Z

417

Multiple paternity in Asclepias syriaca using a paired-fruit analysis  

E-Print Network (OSTI)

Multiple paternity in Asclepias syriaca using a paired-fruit analysis Julie J. Gold and Joel S. Shore Introduction Abstract: We investigated the extent of multiple paternity within and between fruits within fruits. When pairs of fruits obtained from individual ramets were analyzed in a similar manner

Shore, Joel S.

418

OPPENHEIM CONJECTURE FOR PAIRS CONSISTING OF A LINEAR FORM AND A QUADRATIC FORM  

E-Print Network (OSTI)

OPPENHEIM CONJECTURE FOR PAIRS CONSISTING OF A LINEAR FORM AND A QUADRATIC of the Oppenheim conjecture, we prov* *e that the set {(Q(x), L(x)) : x 2 Zd} is dense in R2provided that Q; OPPENHEIM CONJECTURE FOR PAIRS 2 It is easy to see that the second condition

Gorodnik, Alexander

419

Monte Carlo calculations of pair production in high-intensity laser-plasma interactions  

E-Print Network (OSTI)

Gamma-ray and electron-positron pair production will figure prominently in laser-plasma experiments with next generation lasers. Using a Monte Carlo approach we show that straggling effects arising from the finite recoil an electron experiences when it emits a high energy photon, increase the number of pairs produced on further interaction with the laser fields.

Roland Duclous; John Kirk; Anthony Bell

2010-10-21T23:59:59.000Z

420

Iron Is an Essential Cause of Fishy Aftertaste Formation in Wine and Seafood Pairing  

Science Journals Connector (OSTI)

Iron Is an Essential Cause of Fishy Aftertaste Formation in Wine and Seafood Pairing ... Fishy aftertaste is sometimes perceived in wine with fish and seafood pairing. ... However, what component of wine clashes with seafood or what compound contributes to the unpleasant fishy aftertaste in the mouth remains an open problem. ...

Takayuki Tamura; Kiyoshi Taniguchi; Yumiko Suzuki; Toshiyuki Okubo; Ryoji Takata; Tomonori Konno

2009-08-26T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

Nuclear Physics A 781 (2007) 317341 Symmetry energies, pairing energies, and mass  

E-Print Network (OSTI)

Nuclear Physics A 781 (2007) 317­341 Symmetry energies, pairing energies, and mass equations J of the respective mass equation since symmetry energies are related to the curvature of the nuclear mass surface and pairing energies of atomic nuclei are related to the differences between the excitation energies

O'Donnell, Tom

422

INTRODUCTION Meiosis is the specialized pair of cell divisions that normally  

E-Print Network (OSTI)

and late meiotic prophase. Although pairing and synapsis refer to similar and interrelated processes of homologous chromosomes are largely coincident processes, ruling out a role for premeiotic pairing reorganization are prerequisite steps to the DNA sequence- based homology-search process in higher eukaryotes

Bass, Hank W.

423

Kinetics of electron-positron pair plasmas using an adaptive Monte Carlo method  

E-Print Network (OSTI)

A new algorithm for implementing the adaptive Monte Carlo method is given. It is used to solve the relativistic Boltzmann equations that describe the time evolution of a nonequilibrium electron-positron pair plasma containing high-energy photons and pairs. The collision kernels for the photons as well as pairs are constructed for Compton scattering, pair annihilation and creation, bremsstrahlung, and Bhabha & Moller scattering. For a homogeneous and isotropic plasma, analytical equilibrium solutions are obtained in terms of the initial conditions. For two non-equilibrium models, the time evolution of the photon and pair spectra is determined using the new method. The asymptotic numerical solutions are found to be in a good agreement with the analytical equilibrium states. Astrophysical applications of this scheme are discussed.

Ravi P. Pilla; Jacob Shaham

1997-02-21T23:59:59.000Z

424

3D Relativistic Hartree-Bogoliubov model with a separable pairing interaction  

E-Print Network (OSTI)

A recently introduced separable pairing force for relativistic Hartree-Bogoliubov (RHB) calculations, adjusted in nuclear matter to the pairing gap of the Gogny force, is employed in the 3D RHB model for triaxial shapes. The pairing force is separable in momentum space but, when transformed to coordinate space in calculations of finite nuclei, it is no longer separable because of translational invariance. The corresponding pairing matrix elements are represented as a sum of a finite number of separable terms in the basis of a 3D harmonic oscillator. The 3D RHB model is applied to the calculation of binding energy surfaces and pairing energy maps for a sequence of even-A Sm isotopes.

T. Niksic; D. Vretenar; Y. Tian; Z. Y. Ma; P. Ring

2009-12-07T23:59:59.000Z

425

Identification of novel ionizing radiation signaling targets in reconstituted human skin  

NLE Websites -- All DOE Office Websites (Extended Search)

of novel ionizing radiation signaling targets in reconstituted human skin of novel ionizing radiation signaling targets in reconstituted human skin Feng Yang, Katrina M. Waters, Bobbie-Jo Webb-Robertson, Lye-Meng Markillie, Rachel M. Wirgau, Shawna M. Hengel, Ljiljana Pasa-Tolic, and David L. Stenoien. Pacific Northwest National Laboratory Our focus has been on identifying the early events that occur after low dose ionizing radiation exposure that precede and often regulate downstream events such as altered transcription, protein secretion and epigenetic regulation. Phosphorylation is one of the earliest detectible events that occurs following radiation exposure and plays important roles in multiple biological pathways including DNA damage repair, transcription, apoptosis, and cell cycle progression. Very robust

426

Investigation of non-targeted effects of low dose ionizing radiation on the mammary gland  

NLE Websites -- All DOE Office Websites (Extended Search)

non-targeted effects of low dose ionizing radiation on the mammary gland non-targeted effects of low dose ionizing radiation on the mammary gland utilizing three-dimensional culture models of mammary cells derived from mouse strains that differ in susceptibility to tumorigenesis Joni D. Mott, Antoine M. Snijders, Alvin Lo, Dinah Levy-Groesser, Bahram Parvin, Andrew J. Wyrobek, Jian-Hua Mao, and Mina J. Bissell Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720 Goal: Within the Lawrence Berkeley National Laboratory's SFA, Project 2, our studies focus on utilizing three dimensional (3D) cell culture models as surrogates for in vivo studies to determine how low doses of ionizing radiation influence mammary gland tissue architecture and how this may relate both to tumor progression and/or adaptive response.

427

Low Dose Radiation Research Program: Low Dose Ionizing Radiation-Induced  

NLE Websites -- All DOE Office Websites (Extended Search)

Low Dose Ionizing Radiation-Induced Effects in Irradiated and Low Dose Ionizing Radiation-Induced Effects in Irradiated and Unirradiated cells: Pathways Analysis in Support of Risk Assessment. Authors: B.E. Lehnert, R. Cary, D. Gadbois, and G. Gupta. Institutions: Bioscience Division, Los Alamos National Laboratory. The scientific literature presents a confusing picture concerning health risks due to low dose ionizing radiation (LDIR), e.g., <1-10 cGy. Some effects of LDIR such as enhanced rates of cell proliferation and the induction of radioadaptation may be benign under some circumstances. Other evidence suggests LDIR can be hazardous and that a threshold for potentially detrimental responses, e.g., increases in intracellular reactive oxygen species (ROS), increases in sister chromatid exchanges (SCE), alterations in gene or protein expression profiles, and increased

428

Molecular mechanisms and cellular consequences of low-dose exposure to ionizing  

NLE Websites -- All DOE Office Websites (Extended Search)

mechanisms and cellular consequences of low-dose exposure to ionizing mechanisms and cellular consequences of low-dose exposure to ionizing radiation Andrew J. Wyrobek 1 , Francesco Marchetti 1 , Xiu Lowe 1 , Xiaochen Lu 2 , Terumi Kohwi- Shigematsu 1 , Brian Davy 1 , Thomas E. Schmid 1 , Sylvia Ahn 1 , Tarlochan Nijjar 1 Matthew A. Coleman 2 , Contact information: ajwyrobek@gmail.com 1 Life Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 2 BioSciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA. The objectives of this research are to characterize the genome-wide molecular responses to low-dose ionizing radiation (<10cGy), to identify tissue and cell-type specific differences in pathways responses, and to identify the pivotal molecular pathway responses that control risks to genome integrity and health. This project utilizes mouse in

429

Influence of ionization on reflection of solitary waves in a magnetized plasma  

SciTech Connect

The reflection of nonlinear solitary waves is studied in a nonuniform, magnetized plasma diffusing from an ionization source along the magnetic field lines. Contribution of the ionization term is included in the continuity equation. The behavior of solitary waves is governed by modified form of Korteweg–de Vries equation (called mKdV equation). In order to investigate the reflection of solitary waves, the mKdV equations for the right and left going waves are derived, and solved by finding new transformations coupled at the point of reflection, for obtaining the expression of reflection coefficient. Contrary to the case of usual inhomogeneous plasma, the present analysis shows that a combination of usual sech{sup 2} structure and tanh structure (called the tail of soliton) arises due to the influence of ionization term. Interestingly, this tailing structure disappears after the reflection of the soliton and hence, the soliton is downshifted prominently.

Jyoti,; Malik, Hitendra K. [Plasma Waves and Particle Acceleration Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110 016 (India)] [Plasma Waves and Particle Acceleration Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110 016 (India); Kumar, Ravinder [Department of Physics, Janta Vedic College Baraut, Uttar Pradesh 265 001 (India)] [Department of Physics, Janta Vedic College Baraut, Uttar Pradesh 265 001 (India); Dahiya, Raj P. [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi 110 016 (India)] [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi 110 016 (India)

2013-09-15T23:59:59.000Z

430

Ionization equilibrium and equation of state of hydrogen plasmas in strong magnetic fields  

E-Print Network (OSTI)

We study hydrogen plasmas at magnetic fields B ~ 10^{12}-10^{13} Gauss, densities ~ 10^{-3}-10^3 g/cc and temperatures T ~ 10^{5.5}-10^{6.5} K, typical of photospheres of middle-aged cooling neutron stars. We construct an analytical free energy model of the partially ionized plasma, including into consideration the decentred atomic states, which arise due to the thermal motion across the strong field. We show that these states, neglected in previous studies, may contribute appreciably into thermodynamics of the outer atmospheric layers at density below 1 g/cc and typical B and T. We take into account Coulomb non-ideality of the ionized component of the plasma affected by intense magnetic field. Ionization degree, occupancies and equation of state are calculated, and their dependences on the temperature, density and magnetic field are studied.

Potekhin, A Yu; Shibanov, Yu A; Ventura, J; Shibanov, Yu. A.

1999-01-01T23:59:59.000Z

431

Ionization equilibrium and equation of state of hydrogen plasmas in strong magnetic fields  

E-Print Network (OSTI)

We study hydrogen plasmas at magnetic fields B ~ 10^{12}-10^{13} Gauss, densities ~ 10^{-3}-10^3 g/cc and temperatures T ~ 10^{5.5}-10^{6.5} K, typical of photospheres of middle-aged cooling neutron stars. We construct an analytical free energy model of the partially ionized plasma, including into consideration the decentred atomic states, which arise due to the thermal motion across the strong field. We show that these states, neglected in previous studies, may contribute appreciably into thermodynamics of the outer atmospheric layers at density below 1 g/cc and typical B and T. We take into account Coulomb non-ideality of the ionized component of the plasma affected by intense magnetic field. Ionization degree, occupancies and equation of state are calculated, and their dependences on the temperature, density and magnetic field are studied.

A. Y. Potekhin; G. Chabrier; Yu. A. Shibanov; J. Ventura

1998-11-27T23:59:59.000Z

432

The structure of approximate two electron wavefunctions in intense laser driven ionization dynamics  

E-Print Network (OSTI)

The structure of approximate two electron wavefunction is deeply investigated, both theoretically and numerically, in the strong-field driven ionization dynamics. Theoretical analyses clarify that for two electron singlet systems, the previously proposed time-dependent extended Hartree-Fock (TD-EHF) method [Phys. Rev. A 51, 3999 (1995)] is equivalent to the multiconfiguration time-dependent Hartree-Fock method with two occupied orbitals. The latter wavefunction is further transformed into the natural expansion form, enabling the direct propagation of the natural orbitals (NOs). These methods, as well as the conventional time-dependent Hartree-Fock (TDHF) method, are numerically assessed for the description of ionization dynamics of one-dimensional helium atom model. This numerical analysis (i) explains the reason behind the well-known failure of TDHF method to describe tunneling ionization, (ii) demonstrates the interpretive power of the TD-EHF wavefunction both in the original nonorthogonal and the NO-based ...

Sato, Takeshi

2014-01-01T23:59:59.000Z

433

Dissociative multiple ionization of diatomic molecules by extreme-ultraviolet free-electron-laser pulses  

SciTech Connect

Nuclear dynamics in dissociative multiple ionization processes of diatomic molecules exposed to extreme-ultraviolet free-electron-laser pulses is studied theoretically using the Monte Carlo wave packet approach. By simulated detection of the emitted electrons, the model reduces a full propagation of the system to propagations of the nuclear wave packet in one specific electronic charge state at a time. Suggested ionization channels can be examined, and kinetic energy release spectra for the nuclei can be calculated and compared with experiments. Double ionization of O{sub 2} is studied as an example, and good agreement with published experimental data is obtained by simulating the dynamics on ten different electronic Born-Oppenheimer curves.

Leth, Henriette Astrup; Madsen, Lars Bojer [Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)

2011-06-15T23:59:59.000Z

434

Reconstruction of ionization probabilities from spatially averaged data in N-dimensions  

E-Print Network (OSTI)

We present an analytical inversion technique which can be used to recover ionization probabilities from spatially averaged data in an N-dimensional detection scheme. The solution is given as a power series in intensity. For this reason, we call this technique a multiphoton expansion (MPE). The MPE formalism was verified with an exactly solvable inversion problem in 2D, and probabilities in the postsaturation region, where the intensity-selective scanning approach breaks down, were recovered. In 3D, ionization probabilities of Xe were successfully recovered with MPE from simulated (using the ADK tunneling theory) ion yields. Finally, we tested our approach with intensity-resolved benzene ion yields showing a resonant multiphoton ionization process. By applying MPE to this data (which was artificially averaged) the resonant structure was recovered-suggesting that the resonance in benzene may have been observable in spatially averaged data taken elsewhere.

J. Strohaber; A. A. Kolomenskii; H. A. Schuessler

2010-03-31T23:59:59.000Z

435

Absolute cross section for positron-impact ionization of hydrogen near threshold  

SciTech Connect

We investigate positron-impact ionization of hydrogen near threshold using the hyperspherical hidden crossing method (HHCM). Previously, Ihra et al. Phys. Rev. Lett. 78 4027 (1997) used the HHCM to obtain the extended Wannier threshold law for zero angular momentum. We extend their analysis to higher angular momentum L and show that the extended Wannier threshold law is L independent. We also calculate the absolute partial-wave ionization cross sections for L=0, 1, 2, and 3 and compare our results with other calculations and with experimental measurements. The HHCM calculation provides an explanation for the very small S-wave and large D-wave contributions to the ionization cross section in terms of destructive and constructive interference, respectively.

Jansen, Krista [University of North Texas; Ward, S.J. [University of North Texas; Macek, Joseph H [ORNL

2009-01-01T23:59:59.000Z

436

Multiphoton Ionization of Magnesium in a Ti-Sapphire laser field  

E-Print Network (OSTI)

In this paper we report the theoretical results obtained for partial ionization yields and the above-threshold ionization (ATI) spectra of Magnesium in a Ti:sapphire laser field (804 nm) in the range of short pulse duration (20-120 fs). Ionization yield, with linearly polarized light for a 120 fs laser pulse, is obtained as a function of the peak intensity motivated by recent experimental data \\cite{gillen:2001}. For this, we have solved the time-dependent Schr\\"{o}dinger equation nonperturbatively on a basis of discretized states obtained with two different methods; one with the two-electron wavefunction relaxed at the boundaries, giving a quadratic discretized basis and the other with the two-electron wavefunction expanded in terms of Mg$^+$-orbitals plus one free electron allowing the handling of multiple continua (open channels). Results, obtained with the two methods, are compared and advantages and disadvantages of the open-channel method are discussed.

Nikolopoulos, L A A; Lambropoulos, P; 10.1140/epjd/e2003-00265-7

2013-01-01T23:59:59.000Z

437

Orientation and alignment effects in electron-induced ionization of a single oriented water molecule  

SciTech Connect

We here report a theoretical study about the orientation effect on the total ionization cross sections for a single oriented water molecule. The theoretical description of the ionization process is performed within the first Born framework with a collisional system including an initial state composed of a projectile and a water target molecule described by a plane wave and an accurate one-center molecular wave function, respectively, and a final state constituted by a slow ejected electron represented by a Coulomb wave and a scattered (fast) electron projectile described by a plane wave. Secondary electron energetic distributions as well as total cross sections are then compared for particular target configurations pointing out strong alignment and orientation effects on the description of the ionization process.

Champion, C. [Laboratoire de Physique Moleculaire et des Collisions, ICPMB (FR CNRS 2843), Universite Paul Verlaine-Metz, 1 boulevard Arago, F-57078 Metz Cedex 3 (France); Rivarola, R. D. [Instituto de Fisica Rosario, CONICET and Universidad Nacional de Rosario, Avenida Pellegrini 250, 2000 Rosario (Argentina)

2010-10-15T23:59:59.000Z

438

Rocket Determination of the Ionization Spectrum of Charged Cosmic Rays at ?=41°N  

Science Journals Connector (OSTI)

In a V-2 rocket measurement at ?=41°N an analysis has been made of the various components of the charged particle radiation on the basis of ionization and absorption in lead. The ionization was determined by two proportional counters, the particle paths through which were defined by Geiger counters. With increasing zenith angle toward the north, the intensity is found to be substantially constant until the earth ceases to cover the under side of the telescope. The intensity of all particles with range ?7 g/cm2 is 0.079±0.005 (cm2secsteradian)-1. Of this an intensity 0.012±0.002 is absorbed in the next 14 g/cm2. The ionization measurement is consistent with 34 of these soft particles being electrons of 2.

G. J. Perlow; L. R. Davis; C. W. Kissinger; J. D. Shipman; Jr.

1952-10-15T23:59:59.000Z

439

Photoelectron studies of resonant multiphoton ionization of CO via the A /sup 1/Pi state  

SciTech Connect

We report measurements of multiphoton ionization of CO involving a three photon resonance to the v = 1--3 levels of the CO A /sup 1/Pi state followed by the absorption of either two (v = 3) or three (v = 1,2) additional photons to reach the ionization continua. In one measurement, the CO/sup +/ ion intensity is measured as a function of wavelength, yielding the rotational structure of the intermediate resonant state. In a second measurement, the laser frequency is set at the v = 1--3 bandheads and the kinetic energy spectra of the ejected electrons are measured. The observed vibrational branching ratios in these photoelectron spectra do not follow the pattern predicted by the Franck--Condon overlap between the intermediate A /sup 1/Pi state and the ionization continua. Several possible causes for this (not unexpected) deviation from Franck--Condon behavior are discussed.

Pratt, S.T.; Poliakoff, E.D.; Dehmer, P.M.; Dehmer, J.L.

1983-01-01T23:59:59.000Z

440

Mechanisms Underlying Cellular Responses to Low Doses/Low LET Ionizing Radiation in Primary Haemopoietic Cells.  

NLE Websites -- All DOE Office Websites (Extended Search)

Mechanisms Underlying Cellular Responses to Low Doses/Low LET Ionizing Radiation Mechanisms Underlying Cellular Responses to Low Doses/Low LET Ionizing Radiation in Primary Haemopoietic Cells. Munira Kadhim 1 , Stefania Militi 1 , Debbie Bowler 1 , Denise Macdonald 1 and Kevin Prise 2 1 Radiation and Genome Stability Unit, MRC, Harwell, Didcot, Oxon, OX11 0RD, UK 2 Gray Cancer Institute ,PO Box 100, Mount Vernon Hospital, Northwood, HA6 2JR, UK Because the human population is genetically heterogeneous, it is important to understand the role that heterogeneity may play in radiation response. Exposure to ionizing radiation can lead to a suite of changes, including increased mutation rate, delayed reproductive cell death, and delayed chromosomal aberrations, all of which are manifestations of the complex genomic instability (GI) phenotype. Following exposure to either high LET

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441

COSMIC EVOLUTION OF STAR FORMATION ENHANCEMENT IN CLOSE MAJOR-MERGER GALAXY PAIRS SINCE z = 1  

SciTech Connect

The infrared (IR) emission of 'M {sub *} galaxies' (10{sup 10.4} {<=} M {sub star} {<=} 10{sup 11.0} M {sub Sun }) in galaxy pairs, derived using data obtained in Herschel (PEP/HerMES) and Spitzer (S-COSMOS) surveys, is compared to that of single-disk galaxies in well-matched control samples to study the cosmic evolution of the star formation enhancement induced by galaxy-galaxy interaction. Both the mean IR spectral energy distribution and mean IR luminosity of star-forming galaxies (SFGs) in SFG+SFG (S+S) pairs in the redshift bin of 0.6 < z < 1 are consistent with no star formation enhancement. SFGs in S+S pairs in a lower redshift bin of 0.2 < z < 0.6 show marginal evidence for a weak star formation enhancement. Together with the significant and strong sSFR enhancement shown by SFGs in a local sample of S+S pairs (obtained using previously published Spitzer observations), our results reveal a trend for the star formation enhancement in S+S pairs to decrease with increasing redshift. Between z = 0 and z = 1, this decline of interaction-induced star formation enhancement occurs in parallel with the dramatic increase (by a factor of {approx}10) of the sSFR of single SFGs, both of which can be explained by the higher gas fraction in higher-z disks. SFGs in mixed pairs (S+E pairs) do not show any significant star formation enhancement at any redshift. The difference between SFGs in S+S pairs and in S+E pairs suggests a modulation of the sSFR by the intergalactic medium (IGM) in the dark matter halos hosting these pairs.

Xu, C. K.; Shupe, D. L.; Bock, J.; Bridge, C.; Cooray, A.; Lu, N.; Schulz, B. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Bethermin, M.; Aussel, H.; Elbaz, D.; Le Floc'h, E.; Riguccini, L. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu, CNRS, Universite Paris Diderot, CE-Saclay, pt courrier 131, F-91191 Gif-sur-Yvette (France); Berta, S.; Lutz, D.; Magnelli, B. [Max-Planck-Institut fuer Extraterrestrische Physik (MPE), Postfach 1312, D-85741 Garching (Germany); Conley, A. [Center for Astrophysics and Space Astronomy 389-UCB, University of Colorado, Boulder, CO 80309 (United States); Franceschini, A. [Dipartimento di Astronomia, Universita di Padova, vicolo Osservatorio, 3, I-35122 Padova (Italy); Marsden, G. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Oliver, S. J. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Pozzi, F. [INAF-Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monte Porzio Catone (Italy); and others

2012-11-20T23:59:59.000Z

442

Multiple ionization in single, low-MeV collisions of Kr ions with Kr atoms  

Science Journals Connector (OSTI)

The energy and relative intensities of L-MM Auger lines show that for low-MeV Kr+-Kr collisions most of the ionization takes place during the collision, due to the prompt emission of as many as 12 electrons per atom. The later decay of L-shell vacancies contributes in only a minor way to the final ionization state. These results provide insights into a variety of collision phenomena, including shifts in Auger and x-ray energies, fluorescence yields, and equilibrium charge distributions in high-Z foils.

P. deGroot; M. J. Zarcone; Q. C. Kessel

1987-09-15T23:59:59.000Z

443

Quantum statistical effect on ionizing collisions of ultracold metastable Kr isotopes  

Science Journals Connector (OSTI)

Ultracold ionizing collisions of laser-cooled Kr isotopes in the 1s5[4p55s:3P2] metastable state are investigated. When the collision energy is reduced below the p-wave centrifugal barrier of 80 ?K, the ratio of the ionizing collision rate between polarized and unpolarized Kr83 atoms is found to decrease. This is a direct evidence of the quantum interference of two identical Fermi particles. The experimental results are compared with the calculation based on the simplified inelastic collision theory.

Hidetoshi Katori; Hideyuki Kunugita; Tetsuya Ido

1995-12-01T23:59:59.000Z

444

Lattice-Boltzmann simulation of laser interaction with weakly ionized helium plasmas  

SciTech Connect

This paper presents a lattice Boltzmann method for laser interaction with weakly ionized plasmas considering electron impact ionization and three-body recombination. To simulate with physical properties of plasmas, the authors' previous work on the rescaling of variables is employed and the electromagnetic fields are calculated from the Maxwell equations by using the finite-difference time-domain method. To calculate temperature fields, energy equations are derived separately from the Boltzmann equations. In this way, we attempt to solve the full governing equations for plasma dynamics. With the developed model, the continuous-wave CO{sub 2} laser interaction with helium is simulated successfully.

Li Huayu; Ki, Hyungson [Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan 48824-1226 (United States); School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

2010-07-15T23:59:59.000Z

445

Ionized-impurity scattering of quasi-two-dimensional quantum-confined carriers  

Science Journals Connector (OSTI)

Hall-effect measurements of electron mobility in anti-modulation-doped GaAs/AlGaAs quantum wells indicate that the ionized-impurity scattering of a quasi-two-dimensional electron gas immersed in the identical concentration of ionized impurities is greater than that of a bulk electron gas of the same density. This enhancement results from an increase of the overlap of the electronic wave function with the impurities, a decrease in screening, and an increase in large-angle scattering. The enhanced scattering rate may be further increased by confining the dopant ions to a deltalike doping profile in the center of the well.

W. Ted Masselink

1991-03-18T23:59:59.000Z

446

A programme for electron-impact broadening parameter calculations of ionized rare-earth element lines  

E-Print Network (OSTI)

In order to provide atomic data needed for astrophysical investigations, a set of electron-impact broadening parameters for ionized rare-earth element lines should be calculated. We are going to calculate the electron-impact broadening parameters for more than 50 transitions of ionized rare-earth elements. Taking into account that the spectra of these elements are very complex, for calculation we can use the modified semiempirical approach - MSE or simplified MSE. Also, we can estimate these parameters on the basis of regularities and systematic trends.

L. C. Popovic; M. S. Dimitrijevic

1998-05-15T23:59:59.000Z

447

Ionization of Rydberg atoms at metallic surfaces: Influence of stray fields  

SciTech Connect

The ionization of xenon Rydberg atoms at metallic surfaces is examined. The data show that, when the effects of stray electric 'patch' fields present on the surface are taken into account, ionization is well described by a simple over-the-barrier model. The patch fields are determined from direct measurements of the potential variations across the target surfaces using Kelvin probe force microscopy. Monte Carlo techniques are used to model the atom-surface interaction. The results confirm the important role that patch fields can play during Rydberg atom-surface interactions and suggest that such interactions can provide a sensitive probe of stray fields at surfaces.

Pu, Y.; Neufeld, D. D.; Dunning, F. B. [Department of Physics and Astronomy and the Rice Quantum Institute, Rice University MS61, Houston, Texas 77005-1892 (United States)

2010-04-15T23:59:59.000Z

448

Electron impact ionization: A new parameterization for 100 eV to 1 MeV electrons  

E-Print Network (OSTI)

Electron impact ionization: A new parameterization for 100 eV to 1 MeV electrons Xiaohua Fang,1 of the ionization rate in the Earth's atmosphere due to precipitating energetic electrons. Precipitating electrons the atmosphere. In this study, two electron transport models (whose validity has been verified by observations

Jackman, Charles H.

449

Ion distribution around a charged rod in one and two component solvents: Preferential solvation and first order ionization phase transition  

E-Print Network (OSTI)

and first order ionization phase transition Ryuichi Okamotoa and Akira Onukib Department of Physics, Kyoto phase transition of weak-to-strong ionization for hydrophobic chains. This transition line starts from, which undergoes a discontinuous phase transition be- tween elongated coil and compact globule depending

450

Human In vivo Dose-Response to Controlled, Low-Dose Low Linear Energy Transfer Ionizing Radiation Exposure  

Science Journals Connector (OSTI)

...effects of low-dose low-linear energy transfer ionizing radiation (LDIR) in humans...direct evidence that doses in the range of 1 to 10 cGy...the intentional radiation of healthy tissue...the response to ionizing radiation. Attempts...

Zelanna Goldberg; David M. Rocke; Chad Schwietert; Susanne R. Berglund; Alison Santana; Angela Jones; Jörg Lehmann; Robin Stern; Ruixiao Lu; and Christine Hartmann Siantar

2006-06-15T23:59:59.000Z

451

Altered Telomere Nuclear Matrix Interactions and Nucleosomal Periodicity in Ataxia Telangiectasia Cells before and after Ionizing Radiation Treatment  

Science Journals Connector (OSTI)

...mean P/mean S Mean () Range () Mean () Range () RKO 71 67-75 29 25-33...significant. Influence of ionizing radiation on telomere-nuclear matrix...cells were treated with a dose of 5 Gy of ionizing radiation, and proportions of S...

Lubomir B. Smilenov; Sonu Dhar; Tej K. Pandita

1999-10-01T23:59:59.000Z

452

Human In vivo Dose-Response to Controlled, Low-Dose Low Linear Energy Transfer Ionizing Radiation Exposure  

Science Journals Connector (OSTI)

...biotinylated nucleotide analogue/ribonucleotide mix. The biotinylated cRNA targets were then...dose-response to controlled, low-dose low linear energy transfer ionizing radiation exposure. | The effect of low doses of low-linear energy transfer (photon) ionizing radiation...

Zelanna Goldberg; David M. Rocke; Chad Schwietert; Susanne R. Berglund; Alison Santana; Angela Jones; Jörg Lehmann; Robin Stern; Ruixiao Lu; and Christine Hartmann Siantar

2006-06-15T23:59:59.000Z

453

Photon-pair generation in photonic crystal fibrebre with a 1.5GHz modelocked VECSEL  

E-Print Network (OSTI)

Four-wave mixing (FWM) in optical fibre is a leading technique for generating high-quality photon pairs. We report the generation of photon pairs by spontaneous FWM in photonic crystal fibre pumped by a 1.5 GHz repetition-rate vertical-external-cavity surface-emitting laser (VECSEL). The photon pairs exhibit high count rates and a coincidence-to-accidental ratio of over 80. The VECSEL's high repetition-rate, high average power, tunability, and small footprint make this an attractive source for quantum key distribution and photonic quantum-state engineering.

Oliver J. Morris; Robert J. A. Francis-Jones; Keith G. Wilcox; Anne C. Tropper; Peter J. Mosley

2014-09-09T23:59:59.000Z

454

Geometric Origin of Pair Production by Electric Field in de Sitter Space  

E-Print Network (OSTI)

The particle production in a de Sitter space provides an interesting model to understand the curvature effect on Schwinger pair production by a constant electric field or Schwinger mechanism on the de Sitter radiation. For that purpose, we employ the recently introduced complex analysis method, in which the quantum evolution in the complex time explains the pair production via the geometric transition amplitude and gives the pair-production rate as the contour integral. We compare the result by the contour integral with that of the phase-integral method.

Sang Pyo Kim

2014-04-15T23:59:59.000Z

455

Proton?Neutron Pairing Interaction in Neutron Rich A ?=?132 Nuclei  

Science Journals Connector (OSTI)

In infinite nuclear systems such as neutron stars pairing phenomena have a particular interest in the study of nuclear structure properties. Thus pairing lies at the heart of quantum many body problems and nuclear process connecting to nucleosynthesis. In this work we are interested on the contribution of this aspect for neutron rich nuclei far from stability in the vicinity of doubly magic 132 Sn . The study of A ?=?134 isobar which presents a proton?neutron mixing in valence space based on the proton?neutron correlation properties. Our results using the P d pairing gap calculations are in a good agreement with the experimental data.

N. Laouet; F. Benrachi; M. Khiter; N. Benmicia; H. Saifi

2010-01-01T23:59:59.000Z

456

Superconductivity of a system with quasilocalized pairs taking account of inequivalence of sites  

SciTech Connect

Superconductivity due to quasilocalized pairs (centers with a negative Hubbard energy U) is studied in the situation when the sites are not completely equivalent (for example, solid solutions). The problem is solved using the BCS theory in the molecular field approximation. The dependences of T/sub c/ and ..delta.. on the scatter of the site energies and on the ratio of the densities of electron pairs and sites are obtained. The highest T/sub c/ is obtained when the density of pairs is half the site density and the scatter of the site energies is least.

Moizhes, B.Y.; Suprun, S.G.

1985-05-01T23:59:59.000Z

457

Description of the even samarium isotopes in the collective pair approximation  

Science Journals Connector (OSTI)

A microscopic multi-j shell calculation is performed to describe the structure of the ground states of the even Sm isotopes within the pairing plus quadrupole model and in the collective pair approximation. Agreement with the experimental data is found for both quadrupole deformation ? and for the diffusivity of the Fermi surface. The variation with the mass number of the structure of the proton and neutron collective pairs is discussed in connection with the increased role of the quadrupole-quadrupole interaction and of the Pauli principle.

F. Catara; A. Insolia; E. Maglione; A. Vitturi

1984-05-01T23:59:59.000Z

458

Pairing states of superfluid {sup 3}He in uniaxially anisotropic aerogel  

SciTech Connect

Stable pairing states of superfluid {sup 3}He in aerogel are examined in the case with a global uniaxial anisotropy which may be created by applying a uniaxial stress to the aerogel. Due to such a global anisotropy, the stability region of an Anderson-Brinkman-Morel (ABM) pairing state becomes wider. In a uniaxially stretched aerogel, the pure polar pairing state with a horizontal line node is predicted to occur, as a three-dimensional superfluid phase, over a measurable width just below the superfluid transition at T{sub c}(P). A possible relevance of the present results to the case with no global anisotropy is also discussed.

Aoyama, Kazushi; Ikeda, Ryusuke [Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan)

2006-02-01T23:59:59.000Z

459

Wave-packet propagation based calculation of above-threshold ionization in the x-ray regime  

E-Print Network (OSTI)

We investigate the multi-photon process of above-threshold ionization for the light elements hydrogen, carbon, nitrogen and oxygen in the hard x-ray regime. Numerical challenges are discussed and by comparing Hartree-Fock-Slater calculations to configuration-interaction-singles results we justify the mean-field potential approach in this regime. We present a theoretical prediction of two-photon above-threshold-ionization cross sections for the mentioned elements. Moreover, we study how the importance of above-threshold ionization varies with intensity. We find that for carbon, at x-ray intensities around $10^{23}{\\rm Wcm}^{-2}$, two-photon above-threshold ionization of the K-shell electrons is as probable as one-photon ionization of the L-shell electrons.

Tilley, Matthew; Santra, Robin

2015-01-01T23:59:59.000Z

460

Densely Ionizing Radiation Acts via the Microenvironment to Promote Aggressive Trp53-Null Mammary Carcinomas  

Science Journals Connector (OSTI)

...charged particle species from protons through uranium at varying energies of up to tens of GeV/amu (7). Estimating the cancer risk...cancer than sparsely ionizing radiation. The unique pattern of energy deposition incurred by particle traversal is considered to...

Irineu Illa-Bochaca; Haoxu Ouyang; Jonathan Tang; Christopher Sebastiano; Jian-Hua Mao; Sylvain V. Costes; Sandra Demaria; Mary Helen Barcellos-Hoff

2014-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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

Extremely Low Dose Ionizing Radiation Up-regulates CXC Chemokines in Normal Human Fibroblasts  

Science Journals Connector (OSTI)

...Research Center for Radiation Safety, National...263-8555 Chiba, Japan. Phone: 81-43-206-3159...doses of ionizing radiation (5). A recent...study showed that Japan has the worlds highest...Research Center for Radiation Safety, National...Inage, Chiba, Japan. fujimora@nirs...

Akira Fujimori; Ryuichi Okayasu; Hiroshi Ishihara; Satoshi Yoshida; Kiyomi Eguchi-Kasai; Kumie Nojima; Satoru Ebisawa; and Sentaro Takahashi

2005-11-15T23:59:59.000Z

462

E-beam ionized channel guiding of an intense relativistic electron beam  

DOE Patents (OSTI)

An IREB is guided through a curved path by ionizing a channel in a gas with electrons from a filament, and confining the electrons to the center of the path with a magnetic field extending along the path. The magnetic field is preferably generated by a solenoid extending along the path. 2 figs.

Frost, C.A.; Godfrey, B.B.; Kiekel, P.D.; Shope, S.L.

1988-05-10T23:59:59.000Z

463

Densely Ionizing Radiation Acts via the Microenvironment to Promote Aggressive Trp53-Null Mammary Carcinomas  

Science Journals Connector (OSTI)

...ionizing radiation. The unique pattern of energy deposition incurred by particle traversal...epithelial cells were positive for K18 (green).Nuclei were counterstained with DAPI...positive either for K18 or K14 (n = 20, green; D), K14+18 type with K14 and K18...

Irineu Illa-Bochaca; Haoxu Ouyang; Jonathan Tang; Christopher Sebastiano; Jian-Hua Mao; Sylvain V. Costes; Sandra Demaria; and Mary Helen Barcellos-Hoff

2014-12-01T23:59:59.000Z

464

The effects of diet and ionizing radiation on azoxymethane induced colon carcinogenesis  

E-Print Network (OSTI)

cancer, by suppressing apoptosis and upregulating proliferation in colonocytes. Diets contained a combination of fish oil or corn oil and either pectin or cellulose. We exposed 40 male Sprague-Dawley rats to 1 Gy ionizing radiation (1 GeV Fe) 10 d prior...

Mann, John Clifford

2006-10-30T23:59:59.000Z

465

ELECTROMAGNETIC POLARIZATION IN PARTIALLY IONIZED PLASMAS WITH STRONG MAGNETIC FIELDS AND NEUTRON STAR ATMOSPHERE MODELS  

E-Print Network (OSTI)

of the relatively high atmosphere density, a proper treatment should take account of the plasma nonidealityELECTROMAGNETIC POLARIZATION IN PARTIALLY IONIZED PLASMAS WITH STRONG MAGNETIC FIELDS AND NEUTRON STAR ATMOSPHERE MODELS Alexander Y. Potekhin,1, 2 Dong Lai,3 Gilles Chabrier,4 and Wynn C. G. Ho5, 6

466

Cancer risk at low doses of ionizing radiation: artificial neural networks inference from atomic bomb survivors  

Science Journals Connector (OSTI)

......with low linear energy transfer (LET...Obviously, the challenge of understanding...but the stable integration of viral DNA...activation should be sustainable for a long period...SA. Directed integration of viral DNA...adeno-associated virus DNA integration. Proc Natl...high linear energy transfer ionizing......

Masao S. Sasaki; Akira Tachibana; Shunichi Takeda

2014-05-01T23:59:59.000Z

467

Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Analysis of Large Polymerases Chain Reaction Products  

SciTech Connect

We have attempted to expand the size range of PCR products that can be analyzed by electroscopy ionization (ESI) Fourier transformion cyclotron resonance (FTICR) mass spectrometry. The mass measurement accuracy obtained illustrates that a signel base substitution could be identified at the size of PCR product with a 7 tesla ESI-FTICR

Wunschel, David S.(BATTELLE (PACIFIC NW LAB)) [BATTELLE (PACIFIC NW LAB); Pasa Tolic, Ljiljana (BATTELLE (PACIFIC NW LAB)) [BATTELLE (PACIFIC NW LAB); Feng, Bingbing (ASSOC WESTERN UNIVERSITY) [ASSOC WESTERN UNIVERSITY; Smith, Richard D.(BATTELLE (PACIFIC NW LAB)) [BATTELLE (PACIFIC NW LAB)

2000-04-01T23:59:59.000Z

468

Photo-Ionization of a Gas by a Discharge in the Same Gas  

Science Journals Connector (OSTI)

Method. Measurements were made in a tube containing two thermionic units electrically shielded from each other. The first served to give a discharge, the second detected ions produced by the radiation from the first by means of their effect on the space charge.Results. Relatively little photo-ionization is produced by arc radiation, while spark excitation and soft x-radiation give a strong effect. Curves of photo-effect versus discharge voltage show critical potentials which have been interpreted as follows: Ionization of n2 rare gas shell—Cs, 13.0; K, 19.0: Spark excitation—Cs, 18.5; K, 21.6; A, 32.2; Ne, 48.0: Double ionization—Cs, 21.5; K, 31.8; A, 34.8; Ne, 54.9: Ionization of n1 rare gas shell—Cs, 39.0; K, 48.0; A, 39.6. The neon II spectrum is excited at 55 volts.It was shown that photo-electric emission from the electrodes was at least ten times as great as the photo-electric emission from the gas, while the current change produced by the space charge effect was more than 2400 times the ion current in argon and caesium, the upper limit being quite indefinite.

F. L. Mohler

1926-07-01T23:59:59.000Z

469

Estimates of Impact Ionization Coefficients in Superlattice-Based Mid-Wavelength Infrared Avalanche Photodiodes  

E-Print Network (OSTI)

Photodiodes C.H. Grein1 , K. Abu El-Rub1,2 , M.E. Flatté3, and H. Ehrenreich4 1 Microphysics Laboratory ionization in type II superlattice mid- wavelength infrared avalanche photodiodes. The strategy to enhance gain, low noise avalanche photodiodes (APDs) with considerable spectral agility. The ability

Flatte, Michael E.

470

The Relative Effects of Direct and Indirect Actions of Ionizing Radiations on Deoxyribonucleic Acid  

Science Journals Connector (OSTI)

...determined over a range of concentrations...means that over this range of concentration...independent of the dose rate and of the hardness of the radiations within the ranges used and identical...indirect actions of ionizing radiations on deoxyribonucleic...

1958-01-01T23:59:59.000Z

471

p53-Mediated Regulation of Proliferating Cell Nuclear Antigen Expression in Cells Exposed to Ionizing Radiation  

Science Journals Connector (OSTI)

...exposed to increasing doses of IR at 24 h posttransfection...cellular response to ionizing radiation in which p53-mediated...IR at 12 Gy, a dose that induced maximal...the 1- to 4-Gy range does not effectively...because a high radiation dose is used and the...

Jin Xu; Gilbert F. Morris

1999-01-01T23:59:59.000Z

472

The Effects of High Dose Rates of Ionizing Radiations on Solutions of Iron and Cerium Salts  

Science Journals Connector (OSTI)

...research-article The Effects of High Dose Rates of Ionizing Radiations on Solutions of Iron and Cerium...of 1.3 duration and over a range of dose rates from 0.5 to 20 000 rads/pulse. Radiation yields at constant dose rate...

1960-01-01T23:59:59.000Z

473

Inactivation of 14-3-3? Influences Telomere Behavior and Ionizing Radiation-Induced Chromosomal Instability  

Science Journals Connector (OSTI)

...per dish was chosen to ensure that about 50 colonies would survive a particular radiation dose treatment. Cells were exposed to ionizing radiation in the dose range of 0 to 8 Gy at room temperature using a 137Cs ray at a dose rate of 1.1 Gy...

Sonu Dhar; Jeremy A. Squire; M. Prakash Hande; Raymund J. Wellinger; Tej K. Pandita

2000-10-01T23:59:59.000Z

474

Transcriptome Analysis Applied to Survival of Shewanella oneidensis MR-1 Exposed to Ionizing Radiation  

Science Journals Connector (OSTI)

...radiation (IR) dose that yields 20...its response to UV radiation (254 nm), which...sensitivity to IR. Ionizing radiation (IR) is potentially...damage caused by given doses of IR for different...similar, although the range of IR resistance...

Xiaoyun Qiu; Michael J. Daly; Alexander Vasilenko; Marina V. Omelchenko; Elena K. Gaidamakova; Liyou Wu; Jizhong Zhou; George W. Sundin; James M. Tiedje

2006-02-01T23:59:59.000Z

475

Ionizing Radiation as an Initiator: Effects of Proliferation and Promotion Time on Tumor Incidence in Mice  

Science Journals Connector (OSTI)

...portion of the dose-response curve these two doses reside, we cannot accu rately say that the...cell carcinomas did not appear to depend on dose. A wider range of doses of ionizing radiation needs to be studied. A representative basal...

Deborah Jaffe and G. Tim Bowden

1987-12-15T23:59:59.000Z

476

Charge localization and fragmentation dynamics of ionized helium clusters M. Ovchinnikov, B. L. Grigorenko,a)  

E-Print Network (OSTI)

to translational energy. This leads to ejection of energetic neutral atoms as well as the ejection of He2 prior- construct the dynamics of charge transfer and localization, and the likely paths of energy dissipation formed by electron impact ionization of the neutral is studied theoretically using mixed quantum

Apkarian, V. Ara

477

Three-photon above-threshold ionization of magnesium F. Martin,2  

E-Print Network (OSTI)

Three-photon above-threshold ionization of magnesium A. Reber,1 F. Marti´n,2 H. Bachau,3 and R. S of magnesium as an electron source 1 have motivated our theoretical study in three-photon above

Berry, R. Stephen

478

Measurement of spin-exchange effects in electron-hydrogen collisions: Further studies of impact ionization  

SciTech Connect

Using a Fano-effect polarized electron source and a state-selected thermally dissociated hydrogen beam, we measured the interference between the direct and exchange scattering amplitudes for electron-impact ionization of atomic hydrogen between 13.8 and 30.0 eV. We report the data from these measurements and the results of corrections applied to previously published data.

Gay, T.J.; Fletcher, G.D.; Alguard, M.J.; Hughes, V.W.; Wainwright, P.F.; Lubell, M.S.

1982-12-01T23:59:59.000Z

479

Mammalian Tissue Response to Low Dose Ionizing Radiation: The Role of Oxidative Metabolism and Intercellular Communication  

SciTech Connect

The objective of the project was to elucidate the mechanisms underlying the biological effects of low dose/low dose rate ionizing radiation in organs/tissues of irradiated mice that differ in their susceptibility to ionizing radiation, and in human cells grown under conditions that mimic the natural in vivo environment. The focus was on the effects of sparsely ionizing cesium-137 gamma rays and the role of oxidative metabolism and intercellular communication in these effects. Four Specific Aims were proposed. The integrated outcome of the experiments performed to investigate these aims has been significant towards developing a scientific basis to more accurately estimate human health risks from exposures to low doses ionizing radiation. By understanding the biochemical and molecular changes induced by low dose radiation, several novel markers associated with mitochondrial functions were identified, which has opened new avenues to investigate metabolic processes that may be affected by such exposure. In particular, a sensitive biomarker that is differentially modulated by low and high dose gamma rays was discovered.

Azzam, Edouard I

2013-01-16T23:59:59.000Z

480

The Escape of Ionizing Photons from OB Associations in Disk Galaxies Radiation Transfer Through Superbubbles  

E-Print Network (OSTI)

By solving the time-dependent radiation transfer problem of stellar radiation through evolving superbubbles within a smoothly varying H I distribution, we have estimated the fraction of ionizing photons emitted by OB associations that escapes the H I disk of our Galaxy. We considered a coeval star-formation history and a Gaussian star-formation history with a time spread sigma_t = 2 Myr. We find that the shells of the expanding superbubbles quickly trap or attenuate the ionizing flux, such that most of the escaping radiation escapes shortly after the formation of the superbubble. Superbubbles of large associations can blowout of the H I disk and form dynamic chimneys, which allow the ionizing radiation directly to escape the H I disk. However, blowout occurs when the ionizing photon luminosity has dropped well below the association's maximum luminosity. For the coeval star-formation history, the fraction of photons that escape each side of the disk in the solar vicinity is f_esc approx 6% (the total fraction ...

Dove, J B; Ferrara, A; Dove, James B.; Ferrara, Andrea

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" 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.


481

Ionization-enhanced currents to an anode in a magnetic field  

Science Journals Connector (OSTI)

Magnetic-field effects are known to play an important role in determining current-collection characteristics of electrodes in magnetoplasmas. In the Parker-Murphy model of current collection, for example, the magnetic field excludes electrons that originate from outside a characteristic collection radius from reaching the anode. In this paper we show that these excluded electrons can dominate current collection through ionization effects, even at pressures well below the Paschen threshold for ionization. We demonstrate this by releasing a controlled current near a spherical anode in a magnetic field, and measuring the resultant anode current. The use of a spatially localized electron source reveals aspects of current collection that are not evident when a background plasma constitutes the electron source. We find that the anode current can exceed the source current by more than two orders of magnitude. The conditions are such that we can neglect the contribution to the anode current from secondary emission at the chamber wall. We therefore attribute the additional current to the flow of electrons released by ionization of the ambient neutral gas and show how the ionization arises from electron trapping.

R. G. Greaves and D. A. Boyd

1991-03-15T23:59:59.000Z

482

Escherichia coli Genes and Pathways Involved in Surviving Extreme Exposure to Ionizing Radiation  

Science Journals Connector (OSTI)

...doses of ionizing radiation does not depend on a single mechanism...metabolism (2). This listing does not include a few gene products...from Deinococcus radiodurans R1 does not restore radioresistance...genetics: a laboratory manual and handbook for Escherichia coli and related...

Rose T. Byrne; Stefanie H. Chen; Elizabeth A. Wood; Eric L. Cabot; Michael M. Cox

2014-07-21T23:59:59.000Z

483

Roles of the Major, Small, Acid-Soluble Spore Proteins and Spore-Specific and Universal DNA Repair Mechanisms in Resistance of Bacillus subtilis Spores to Ionizing Radiation from X Rays and High-Energy Charged-Particle Bombardment  

Science Journals Connector (OSTI)

...mutagenic effects induced by ionizing radiation are thought to be the result...of DNA damage caused by given doses of ionizing radiation for different bacteria are very similar, although the range of ionizing-radiation resistance...

Ralf Moeller; Peter Setlow; Gerda Horneck; Thomas Berger; Günther Reitz; Petra Rettberg; Aidan J. Doherty; Ryuichi Okayasu; Wayne L. Nicholson

2007-11-30T23:59:59.000Z

484

Extremely Low-Dose Ionizing Radiation Causes Activation of Mitogen-activated Protein Kinase Pathway and Enhances Proliferation of Normal Human Diploid Cells  

Science Journals Connector (OSTI)

...stimulative effect of low-dose irradiation. These results indicate that a limited range of low-dose ionizing radiation differentially activates...indicate that a limited range of low-dose ionizing radiation differentially activates...

Keiji Suzuki; Seiji Kodama; and Masami Watanabe

2001-07-15T23:59:59.000Z

485

Pairing of valence electrons as necessary condition for energy minimization in a crystal  

E-Print Network (OSTI)

Pairing of valence electrons can lead to energy minimization of a crystal. It can be proved by use of representation of the valence electrons as plane waves in periodic potential of the crystal.

Dolgopolov Stanislav Olegovich

2014-10-21T23:59:59.000Z

486

Search for neutral MSSM Higgs bosons decaying to a pair of tau leptons in pp collisions  

E-Print Network (OSTI)

A search for neutral Higgs bosons in the minimal supersymmetric extension of the standard model (MSSM) decaying to tau-lepton pairs in pp collisions is performed, using events recorded by the CMS experiment at the LHC. The ...

CMS Collaboration

487

A New Class of RC4 Colliding Key Pairs with Greater Hamming Distance  

Science Journals Connector (OSTI)

In this paper, we discovered a new class of colliding key pairs of RC4, namely ... discovery of RC4 colliding keys with hamming distance greater than one, that is, the colliding ... the probability of the existen...

Jiageng Chen; Atsuko Miyaji

2010-01-01T23:59:59.000Z

488

Resolution of the pair-wise allosteric interactions found in phosphofructokinase from Bacillus stearothermophilus  

E-Print Network (OSTI)

remain, characterization of the remaining six homotropic interactions was performed. Utilizing a linked function approach to quantify the heterotropic and homotropic effects for each hybrid enzyme, we determined that 5 to 6 of the ten pair...

Ortigosa, Allison Dawn

2004-09-30T23:59:59.000Z

489

Neutral Higgs Boson Pair Production in Standard Model with the Fourth Generation Quarks at LHC  

Science Journals Connector (OSTI)

We investigated the neutral Higgs boson pair production at the CERN Large Hadron Collider (LHC) in the SM with four families. We found that the gluon-gluon fusion mode is the most dominant one in producing neutral Higgs boson pair at the LHC, and it can be used to probe the trilinear Higgs coupling. If the heavy quarks of the fourth generation really exist within the SM, they can manifest their effect on the cross section of the Higgs pair production process at the LHC. Our numerical results show that there will be neutral Higgs boson pair production events per year if the next generation heavy quarks really exist, while there will be only events produced per year if there are only three families in the SM.

Sun Hao; Ma Wen-Gan; Zhou Ya-Jin; Sun Yan-Bin; Zhang Ren-You; Hou Hong-Sheng

2004-01-01T23:59:59.000Z

490

Holographic Behavior in Ultrashort Pulse-pair 2d-Velocimetry  

Science Journals Connector (OSTI)

Two-dimensional velocity interferograms of shocked silicon surface illuminated by a pair of 3ps pulses separated by 260 ps can be treated as holograms to numerically refocus narrow...

Erskine, David J; Smith, Raymond F; Ali, Suzanne; Celliers, Peter M; Bolme, Cynthia A

491

Radiative Corrections to Boson Pair Production in e+e- Annihilation  

Science Journals Connector (OSTI)

The expected accuracy of the experiments of SLC and especially LEP I is a great challenge for theorists to produce adequate predictions for e+e- annihilation into fermion pairs at the Z resonance. Indeed their re...

M. Böhm

1989-01-01T23:59:59.000Z

492

Nucleon and nucleon-pair momentum distributions in A?12 nuclei  

We report variational Monte Carlo calculations of single-nucleon momentum distributions for A?12 nuclei and nucleon-pair and nucleon-cluster momentum distributions for A?8. The wave functions have been generated for a Hamiltonian containing the Argonne ?18 two-nucleon and Urbana X three-nucleon potentials. The single-nucleon and nucleon-pair momentum distributions exhibit universal features attributable to the one-pion-exchange tensor interaction The single-nucleon distributions are broken down into proton and neutron components and spin-up and spin-down components where appropriate. The nucleon-pair momentum distributions are given separately for pp and pn pairs. The nucleon-cluster momentum distributions include dp in 3He, tp and dd in S4He, ?d in 6Li,?t in 7Li, and ?? in 8Be. Detailed tables are provided on-line for download.

Wiringa, Robert B. [ANL; Schiavilla, Rocco [ODU, JLAB; Pieper, Steven C. [ANL; Carlson, Joseph A. [LANL

2014-02-01T23:59:59.000Z

493

Pairing preferences of the model mono-valence mono-atomic ions investigated by molecular simulation  

SciTech Connect

We carried out a series of potential of mean force calculations to study the pairing preferences of a series of model mono-atomic 1:1 ions with evenly varied sizes. The probabilities of forming the contact ion pair (CIP) and the single water separate ion pair (SIP) were presented in the two-dimensional plots with respect to the ion sizes. The pairing preferences reflected in these plots largely agree with the empirical rule of matching ion sizes in the small and big size regions. In the region that the ion sizes are close to the size of the water molecule; however, a significant deviation from this conventional rule is observed. Our further analysis indicated that this deviation originates from the competition between CIP and the water bridging SIP state. The competition is mainly an enthalpy modulated phenomenon in which the existing of the water bridging plays a significant role.

Zhang, Qiang [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning (China) [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning (China); Department of Chemistry, Bohai University, Jinzhou 121000 (China); Zhang, Ruiting; Zhao, Ying; Li, HuanHuan; Zhuang, Wei, E-mail: wzhuang@dicp.ac.cn, E-mail: gaoyq@pku.edu.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning (China)] [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning (China); Gao, Yi Qin, E-mail: wzhuang@dicp.ac.cn, E-mail: gaoyq@pku.edu.cn [College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871 (China)

2014-05-14T23:59:59.000Z

494

Optical AND and NOT gates at 40 Gbps using electro-absorption modulator/photodiode pairs.  

SciTech Connect

We demonstrate an optical gate architecture using electro-absorption modulator/photodiode pairs to perform AND and NOT functions. Optical bandwidth for both gates reach 40 GHz. Also shown are AND gate waveforms at 40 Gbps.

Tauke-Pedretti, Anna; Overberg, Mark E.; Skogen, Erik J.; Alford, Charles Fred; Sullivan, Charles Thomas; Vawter, Gregory Allen; Peake, Gregory Merwin; Torres, David L.

2010-06-01T23:59:59.000Z

495

Can disordered radical pair systems provide a basis for a magnetic compass in animals?  

Science Journals Connector (OSTI)

...an ordered subset of proteins, these proteins would then tumble due...become increasingly disordered. The alignment of these selected cytosolic proteins within the cell after...magnetic field angle for ensembles of 2500 radical p