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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.


1

Competitive Vaporization and Decomposition of Liquid RDX Gregory T. Long, Sergey Vyazovkin, Brittany A. Brems, and Charles A. Wight*  

E-Print Network [OSTI]

Versity of Utah, 315 S. 1400 E., Salt Lake City, Utah 84112 ReceiVed: September 17, 1999; In Final Form: January, Brittany A. Brems, and Charles A. Wight* Center for Thermal Analysis, Department of Chemistry, Uni

Utah, University of

2

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

SciTech Connect (OSTI)

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

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

4

Atmospheric sampling glow discharge ionization source  

DOE Patents [OSTI]

An atmospheric sampling glow discharge ionization source that can be used in combination with an analytical instrument which operates at high vacuum, such as a mass spectrometer. The atmospheric sampling glow discharge ionization source comprises a chamber with at least one pair of electrodes disposed therein, an inlet for a gaseous sample to be analyzed and an outlet communicating with an analyzer which operates at subatmospheric pressure. The ionization chamber is maintained at a pressure below atmospheric pressure, and a voltage difference is applied across the electrodes to induce a glow discharge between the electrodes, so that molecules passing through the inlet are ionized by the glow discharge and directed into the analyzer. The ionization source accepts the sample under atmospheric pressure conditions and processes it directly into the high vacuum instrument, bridging the pressure gap and drawing off unwanted atmospheric gases. The invention also includes a method for analyzing a gaseous sample using the glow discharge ionization source described above. 3 figs.

McLuckey, S.A.; Glish, G.L.

1989-07-18T23:59:59.000Z

5

Photoinduced electron transfer in contact ion pairs  

SciTech Connect (OSTI)

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

6

(Ionization in liquids)  

SciTech Connect (OSTI)

This document describes charge transport following ionization of model liquids and how this process may be important in carcinogenesis. 15 refs., 2 figs., 4 tabs. (MHB)

Not Available

1991-01-01T23:59:59.000Z

7

A study of the response of a gas ionization chamber to different sources of ionizing radiation  

E-Print Network [OSTI]

; is the effective average energy to produce one pair (for values, see Table I). Charged particles produced by ionization lose their energy rather quickly in multiple collisions with the gas molecules and assume the thermal energy distribution of the gas. When... of aluminum extrusion ionization chambers to this kind of radiation was investigated. Also, since the TAMU counter is a prototype (1 in x 7in x 7in) of the chambers installed at CDF (1 in x 84in x 84in), the pad-to-wire signal ratio had to be measured...

Zamble?-Die?guez, Filiberto Edmundo

1988-01-01T23:59:59.000Z

8

A surface ionization source  

E-Print Network [OSTI]

The main part of the work described herein is the development and testing of a surface ionization source for use on a collinear fast beam laser spectroscopy apparatus. A description of the previously existing fast beam apparatus is given...

Buzatu, Daniel J.

1995-01-01T23:59:59.000Z

9

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

10

Matched-pair classification  

SciTech Connect (OSTI)

Following an analogous distinction in statistical hypothesis testing, we investigate variants of machine learning where the training set comes in matched pairs. We demonstrate that even conventional classifiers can exhibit improved performance when the input data has a matched-pair structure. Online algorithms, in particular, converge quicker when the data is presented in pairs. In some scenarios (such as the weak signal detection problem), matched pairs can be generated from independent samples, with the effect not only doubling the nominal size of the training set, but of providing the structure that leads to better learning. A family of 'dipole' algorithms is introduced that explicitly takes advantage of matched-pair structure in the input data and leads to further performance gains. Finally, we illustrate the application of matched-pair learning to chemical plume detection in hyperspectral imagery.

Theiler, James P [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

11

Soft ionization of thermally evaporated hypergolic ionic liquid aerosols  

SciTech Connect (OSTI)

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

12

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

13

(Resonance ionization spectroscopy)  

SciTech Connect (OSTI)

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

14

Electrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

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

15

Hysteresis of ionization waves  

SciTech Connect (OSTI)

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

Modulated voltage metastable ionization detector  

SciTech Connect (OSTI)

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

17

First quantized pair interactions  

E-Print Network [OSTI]

The annihilation and creation operators of Quantum Field Theory presuppose a causality condition and so the theory cannot represent macroscopic entanglement. The multiple-particle parametrized Dirac wave equation can represent entanglement without recourse to a causality condition. It is shown here that the parametrized formalism can also represent pair annihilation and creation.

A. F. Bennett

2014-07-01T23:59:59.000Z

18

Plasma Production via Field Ionization  

SciTech Connect (OSTI)

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

19

I. IONIZATION COOLING A. Introduction  

E-Print Network [OSTI]

ionization cooling techniques to reduce the 6­dimensional phase space emittance. B. Cooling TheoryI. IONIZATION COOLING A. Introduction The muon beam at the end of the decay channel is very intense for beam cooling. Cooling by synchrotron radiation, conventional stochastic cooling and conventional

McDonald, Kirk

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

Nuclear Pairs | Jefferson Lab  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the ContributionsArms Control R&D ConsortiumNuclear Pairs High-Resolution

22

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

23

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

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.

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

1994-01-01T23:59:59.000Z

25

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

26

Ionizing Radiation Injury (South Carolina)  

Broader source: Energy.gov [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...

27

Resonance ionization for analytical spectroscopy  

DOE Patents [OSTI]

This invention relates to a method for the sensitive and selective analysis of an atomic or molecular component of a gas. According to this method, the desired neutral component is ionized by one or more resonance photon absorptions, and the resultant ions are measured in a sensitive counter. Numerous energy pathways are described for accomplishing the ionization including the use of one or two tunable pulsed dye lasers.

Hurst, George S. (Oak Ridge, TN); Payne, Marvin G. (Harriman, TN); Wagner, Edward B. (Burchfield Heights, TN)

1976-01-01T23:59:59.000Z

28

Nuclear pairing: basic phenomena revisited  

E-Print Network [OSTI]

I review the phenomena associated with pairing in nuclear physics, most prominently the ubiquitous presence of odd-even mass differences and the properties of the excitation spectra, very different for even-even and odd-A nuclei. There are also significant dynamical effects of pairing, visible in the inertias associated with nuclear rotation and large-amplitude shape deformation.

G. F. Bertsch

2012-03-25T23:59:59.000Z

29

Radiative feedback from ionized gas  

E-Print Network [OSTI]

H2 formation in metal-free gas occurs via the intermediate H- or H2+ ions. Destruction of these ions by photodissociation therefore serves to suppress H2 formation. In this paper, I highlight the fact that several processes that occur in ionized primordial gas produce photons energetic enough to photodissociate H- or H2+ and outline how to compute the photodissociation rates produced by a particular distribution of ionized gas. I also show that there are circumstances of interest, such as during the growth of HII regions around the first stars, in which this previously overlooked form of radiative feedback is of considerable importance.

S. C. O. Glover

2007-03-28T23:59:59.000Z

30

Scientific innovation and resonance ionization spectroscopy  

SciTech Connect (OSTI)

An account is presented of the development and appliations of resonance ionization spectroscopy and one atom detection.

Richmond, C.R.

1981-01-01T23:59:59.000Z

31

Self-consistent chemical model of partially ionized plasmas  

SciTech Connect (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.

Arkhipov, Yu. V.; Baimbetov, F. B.; Davletov, A. E. [Department of Physics, Kazakh National University, Tole Bi 96, Almaty 050012 (Kazakhstan)

2011-01-15T23:59:59.000Z

32

The Ionizing Continuum of Quasars  

E-Print Network [OSTI]

The ionizing continuum shape of quasars is generally not directly observable, but indirect arguments, based on photoionization models and thin accretion disk models suggest that it should peak in the extreme UV, and drop steeply into the soft X-ray regime. However, recent observations of very soft X-ray emission in low z quasars, and far UV emission of high z quasars, suggest that the ionizing continuum of quasars does not peak in the extreme UV, and may extend as a single power law from ~1000 A to ~1 keV. If true, that has interesting implications for photoionization models and for accretion disk models. The proposed revised continuum shape will be tested directly in the near future with FUSE.

Ari Laor

1998-10-15T23:59:59.000Z

33

Pair extended coupled cluster doubles  

E-Print Network [OSTI]

The accurate and efficient description of strongly correlated systems remains an important challenge for computational methods. Doubly occupied configuration interaction (DOCI), in which all electrons are paired and no correlations which break these pairs are permitted, can in many cases provide an accurate account of strong correlations, albeit at combinatorial computational cost. Recently, there has been significant interest in a method we refer to as pair coupled cluster doubles (pCCD), a variant of coupled cluster doubles in which the electrons are paired. This is simply because pCCD provides energies nearly identical to those of DOCI, but at mean-field computational cost (disregarding the cost of the two-electron integral transformation). Here, we introduce the more complete pair extended coupled cluster doubles (pECCD) approach which, like pCCD, has mean-field cost and reproduces DOCI energetically. We show that unlike pCCD, pECCD also reproduces the DOCI wave function with high accuracy. Moreoever, pEC...

Henderson, Thomas M; Scuseria, Gustavo E

2015-01-01T23:59:59.000Z

34

Nuclear Resonance Fluorescence for Nuclear Materials Assay  

E-Print Network [OSTI]

tungsten for various angular ranges of brems- strahlung photon production.tungsten for various angular ranges of bremsstrahlung photon production.tungsten and lead have high densities and relative to lower-Z ma- terials, have larger pair production

Quiter, Brian Joseph

2010-01-01T23:59:59.000Z

35

Ionization probes of molecular structure and chemistry  

SciTech Connect (OSTI)

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

36

Nanospray Desorption Electrospray Ionization: an Ambient Method...  

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

signal as compared to the traditional DESI and discuss imaging applications. Citation: Roach PJ, J Laskin, and A Laskin.2010."Nanospray Desorption Electrospray Ionization: an...

37

Hall Magnetohydrodynamics of weakly-ionized plasma  

E-Print Network [OSTI]

We show that the Hall scale in a weakly ionized plasma depends on the fractional ionization of the medium and, Hall MHD description becomes important whenever the ion-neutral collision frequency is comparable to the ion-gyration frequency, or, the ion-neutral collisional mean free path is smaller than the ion gyro-radius. Wave properties of a weakly-ionized plasma also depends on the fractional ionization and plasma Hall parameters, and whistler mode is the most dominant mode in such a medium. Thus Hall MHD description will be important in astrophysical disks, dark molecular clouds, neutron star crusts, and, solar and planetary atmosphere.

B. P. Pandey; Mark Wardle

2006-08-02T23:59:59.000Z

38

Organic materials and devices for detecting ionizing radiation  

DOE Patents [OSTI]

A .pi.-conjugated organic material for detecting ionizing radiation, and particularly for detecting low energy fission neutrons. The .pi.-conjugated materials comprise a class of organic materials whose members are intrinsic semiconducting materials. Included in this class are .pi.-conjugated polymers, polyaromatic hydrocarbon molecules, and quinolates. Because of their high resistivities (.gtoreq.10.sup.9 ohmcm), these .pi.-conjugated organic materials exhibit very low leakage currents. A device for detecting and measuring ionizing radiation can be made by applying an electric field to a layer of the .pi.-conjugated polymer material to measure electron/hole pair formation. A layer of the .pi.-conjugated polymer material can be made by conventional polymer fabrication methods and can be cast into sheets capable of covering large areas. These sheets of polymer radiation detector material can be deposited between flexible electrodes and rolled up to form a radiation detector occupying a small volume but having a large surface area. The semiconducting polymer material can be easily fabricated in layers about 10 .mu.m to 100 .mu.m thick. These thin polymer layers and their associated electrodes can be stacked to form unique multi-layer detector arrangements that occupy small volume.

Doty, F. Patrick (Livermore, CA); Chinn, Douglas A. (Livermore, CA)

2007-03-06T23:59:59.000Z

39

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

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. 6 figures.

Steinkraus, R.F. Jr.

1994-12-13T23:59:59.000Z

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

The ion pairs and superconducting bosons  

E-Print Network [OSTI]

First, it is shown that the creation of the spinless ion pairs in the lattice, which are hold by the binding with neighbor ion pairs together regarded as covalent. These ion pairs are created by the repulsive potential interaction of two ions which is bound as linear oscillator. The repulsive S-wave scattering between ion pairs and electrons is transformed to the attractive effective interaction between electrons which leads to a creation of electron pairs by a binding energy depending on the condensate fraction of ion pairs $\\frac{N_0}{N}$. In this respect, the absence of ion pairs in the condensate destroys a binding energy of electron pairs and in turn so-called superconductimg phase. As new result presented theory is that the number of the superconducting bosons is not changed in the superconducting phase.

V. N. Minasyan

2009-02-11T23:59:59.000Z

42

Applications of High-Resolution Electrospray Ionization Mass...  

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

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

43

Direct Experimental Observation of the Low Ionization Potentials...  

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

44

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

45

Constraining the nuclear pairing gap with pairing vibrations M. Grasso,1  

E-Print Network [OSTI]

Constraining the nuclear pairing gap with pairing vibrations E. Khan,1 M. Grasso,1 and J. Margueron. Using the same pairing interaction in nuclear matter and in Tin nuclei, the range of densities where I. INTRODUCTION Studies on pairing effects in both nuclear matter and fi- nite nuclei have known

Boyer, Edmond

46

Galaxy pairs align with galactic filaments  

E-Print Network [OSTI]

Context. Gravitational collapse theory and numerical simulations suggest that the velocity field within large-scale galaxy filaments is dominated by motions along the filaments. Aims. Our aim is to check whether observational data reveal any preferred orientation of galaxy pairs with respect to the underlying filaments as a result of the expectedly anisotropic velocity field. Methods. We use galaxy pairs and galaxy filaments identified from the Sloan Digital Sky Survey data. For filament extraction, we use the Bisous model that is based the marked point process technique. During the filament detection, we use the centre point of each pair instead of the positions of galaxies to avoid a built-in influence of pair orientation on the filament construction. For pairs lying within filaments (3012 cases), we calculate the angle between the line connecting galaxies of each pair and their host filament. To avoid redshift-space distortions, the angle is measured in the plain of the sky. Results. The alignment analysis...

Tempel, Elmo

2015-01-01T23:59:59.000Z

47

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.

Shuichiro Ebata; Takashi Nakatsukasa

2013-09-29T23:59:59.000Z

48

Measurement of Scintillation and Ionization Yield and Scintillation Pulse Shape from Nuclear Recoils in Liquid Argon  

E-Print Network [OSTI]

We have measured the scintillation and ionization yield of recoiling nuclei in liquid argon as a function of applied electric field by exposing a dual-phase Liquid Argon Time Projection Chamber (LAr-TPC) to a low energy pulsed narrowband neutron beam produced at the Notre Dame Institute for Structure and Nuclear Astrophysics. Liquid scintillation counters were arranged to detect and identify neutrons scattered in the TPC and to select the energy of the recoiling nuclei. We report measurements of the scintillation yields for nuclear recoils with energies from 10.3 to 57.2 keV and for applied electric fields from 0 to 1000 V/cm. For the ionization yields, we report measurements from 16.9 to 57.2 keV and for electric fields from 50 to 500 V/cm. We also report the observation of an anti-correlation between scintillation and ionization from nuclear recoils, which is similar to the anti-correlation between scintillation and ionization from electron recoils. Assuming that the energy partition in excitons and ion pairs of $^{83m}$Kr internal conversion electrons is comparable to that of $^{207}$Bi conversion electrons, we obtained the numbers of excitons ($N_{\\rm ex}$) and ion pairs ($N_{\\rm i}$) and their ratio ($N_{\\rm ex}$/$N_{\\rm i}$) produced by nuclear recoils from 16.9 to 57.2 keV. Motivated by arguments suggesting direction sensitivity in LAr-TPC signals due to columnar recombination, a comparison of the light and charge yield of recoils parallel and perpendicular to the applied electric field is presented for the first time.

H. Cao; T. Alexander; A. Aprahamian; R. Avetisyan; H. O. Back; A. G. Cocco; F. DeJongh; G. Fiorillo; C. Galbiati; L. Grandi; Y. Guardincerri; C. Kendziora; W. H. Lippincott; C. Love; S. Lyons; L. Manenti; C. J. Martoff; Y. Meng; D. Montanari; P. Mosteiro; D. Olvitt; S. Pordes; H. Qian; B. Rossi; R. Saldanha; S. Sangiorgio; K. Siegl; S. Y. Strauss; W. Tan; J. Tatarowicz; S. Walker; H. Wang; A. W. Watson; S. Westerdale; J. Yoo

2014-07-16T23:59:59.000Z

49

Multiphoton ionization of large water clusters  

SciTech Connect (OSTI)

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

50

Modularity of Termination Using Dependency Pairs ?  

E-Print Network [OSTI]

Modularity of Termination Using Dependency Pairs ? Thomas Arts 1 and J¨urgen Giesl 2 1 Computer@informatik.th­darmstadt.de Abstract. The framework of dependency pairs allows automated ter­ mination and innermost termination proofs of this framework in order to prove termination in a modular way. Our mod­ ularity results significantly increase

Ábrahám, Erika

51

Ionized Hydrogen at Large Galactocentric Distances  

E-Print Network [OSTI]

We summarize recent attempts to detect warm ionized gas at large galactocentric distances. This includes searching for gas at the edges of spirals, in between cluster galaxies, towards extragalactic HI clouds, and towards high velocity clouds and the Magellanic Stream in the Galaxy. With the exception of extragalactic HI clouds, all of these experiments have proved successful. Within each class, we have only observed a handful of objects. It is premature to assess what fraction of the missing baryonic mass fraction might be in the form of ionized gas. But, in most cases, the detections provide a useful constraint on the ambient ionizing flux, and in the case of spiral edges, can even trace dark matter haloes out to radii beyond the reach of radio telescopes.

J. Bland-Hawthorn

1997-04-15T23:59:59.000Z

52

Effect of ionization relaxation on conditions for development of ionization instability  

SciTech Connect (OSTI)

The results of an experimental investigation of the development of ionization instability in completely inert gases are presented for the case of flow of gases across a transverse magnetic field when the ionization relaxation time is much greater than the temperature relaxation time. The experiments were conducted on two electrodeless devices; the first was a coaxial channel with constant transverse cross section and radial magnetic field, while the second was a disc channel with axial magnetic field and radial gas flow. The critical Hall parameter and the time of development of the ionization instability are determined. Recommendations are given for estimating properties of the homogeneous state of the plasma.

Vasil'eva, R.V.; Erofeev, A.V.; Tkhorik, L.G.; Shingarkina, V.A.

1982-03-01T23:59:59.000Z

53

E-Print Network 3.0 - air ionization Sample Search Results  

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

photo-ionization... of this background ionization range from 103 cm-3 (ambient air in buildings) to 107 cm-3 (residual ionization from... with different levels of background ......

54

E-Print Network 3.0 - advanced thin ionization Sample Search...  

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

Physics 76 Photoionized Gas Ionization Equilibrium Ionization Summary: nebula, 4"J diffuse ionizing flux from recombination Case A) Optically thin nebula: J diffuse ...

55

Salt Tolerance of Desorption Electrospray Ionization (DESI)  

SciTech Connect (OSTI)

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

56

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

57

Performance of An Axial Gas Ionization Detector  

E-Print Network [OSTI]

An axial gas ionization chamber has been fabricated for use as a $\\Delta E$ detector in heavy ion induced nuclear reactions. Different operating parameters such as gas type, pressure, anode voltage and anode structures have been optimized. The transparency of the anode structure is observed to play an important role in improving the energy resolution of the detector.

S. Adhikari; C. Basu; C. Samanta; S. S. Brahmachari; B. P. Das; P. Basu

2006-10-11T23:59:59.000Z

58

Muon Cooling via Ionization Andrea Kay Forget  

E-Print Network [OSTI]

decay, as a result of their short lives many of the known cooling techniques (electron, stochastic this cooling technique has never been used many bugs need to be worked out, such as the setup and layout for muon ionization cooling to work efficiently. I. INTRODUCTION Muons need a faster beam cooling technique

Cinabro, David

59

HEALTH EFFECTS OF LOW-LEVEL IONIZING RADIATION  

E-Print Network [OSTI]

LO~Z-lEVEL IONIZIN(l RADIATION Jacob I . Fabti kant April ··OF LOW~LEVEL IONIZING RADIATION BEFORE THE SUBCOMMITTEE ONwill low~level ionizing radiation. restricted primarily to

Fabrikant, Jacob I.

2012-01-01T23:59:59.000Z

60

Classical cutoffs for laser-induced nonsequential double ionization  

SciTech Connect (OSTI)

Classical cutoffs for the momenta of electrons ejected in laser-induced nonsequential double ionization are derived for the recollision-impact-ionization scenario. Such simple cutoff laws can aid in the interpretation of the observed electron spectra.

Milosevic, D.B. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo (Bosnia and Herzegowina); Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin (Germany); Becker, W. [Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin (Germany)

2003-12-01T23:59:59.000Z

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.


61

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

62

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

63

90 Seconds of Discovery: Frustrated Lewis Pairs  

ScienceCinema (OSTI)

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

2014-07-21T23:59:59.000Z

64

90 Seconds of Discovery: Frustrated Lewis Pairs  

SciTech Connect (OSTI)

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

65

Continuous-wave, pair-pumped laser  

SciTech Connect (OSTI)

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

66

Dual Origin of Pairing in Nuclei  

E-Print Network [OSTI]

An essentially "complete" description of the low-energy nuclear structure of the superfluid nucleus $^{120}$Sn and of its odd-$A$ neighbors is provided by the observations carried out with the help of Coulomb excitation and of one-- and of two-- particle transfer reactions, specific probes of vibrations, quasiparticle and pairing degrees of freedom respectively, and of their mutual couplings. These experimental findings are used to stringently test the predictions of a similarly "complete" description of $^{119,120,121}$Sn carried out in terms of elementary modes of excitation which, through their interweaving, melt together into effective fields, each displaying properties reflecting that of all others, there individuality resulting from the actual relative importance of each one. Its implementation is done by solving the Nambu-Gor'kov equations including, for the first time, all medium polarization effects resulting from the interweaving of quasiparticles, spin and surface vibrations, taking into account, within the framework of nuclear field theory (NFT), the variety of processes leading to self-energy, vertex and Pauli principle corrections, and to the induced pairing interaction. Theory provides an overall quantitative account of the experimental findings. From these results one can, not only obtain strong circumstantial evidence for the inevitability for the dual origin of pairing in nuclei but also, extract information which can be used at profit to quantitatively disentangle the contributions to pairing correlations in general and to the pairing gap in particular, arising from the bare and from the induced pairing interactions.

A. Idini; G. Potel; F. Barranco; E. Vigezzi; R. A. Broglia

2014-04-29T23:59:59.000Z

67

Observation of a small oligonucleotide duplex by electrospray ionization mass spectrometry  

SciTech Connect (OSTI)

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

68

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

69

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

70

A numerical scheme for ionizing shock waves  

SciTech Connect (OSTI)

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

71

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

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

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

72

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

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

73

Ionization Equilibrium Timescales in Collisional Plasmas  

E-Print Network [OSTI]

Astrophysical shocks or bursts from a photoionizing source can disturb the typical collisional plasma found in galactic interstellar media or the intergalactic medium. The spectrum emitted by this plasma contains diagnostics that have been used to determine the time since the disturbing event, although this determination becomes uncertain as the elements in the plasma return to ionization equilibrium. A general solution for the equilibrium timescale for each element arises from the elegant eigenvector method of solution to the problem of a non-equilibrium plasma described by Masai (1984) and Hughes & Helfand (1985). In general the ionization evolution of an element Z in a constant electron temperature plasma is given by a coupled set of Z+1 first order differential equations. However, they can be recast as Z uncoupled first order differential equations using an eigenvector basis for the system. The solution is then Z separate exponential functions, with the time constants given by the eigenvalues of the r...

Smith, Randall K

2010-01-01T23:59:59.000Z

74

External ionization mechanisms for advanced thermionic converters  

SciTech Connect (OSTI)

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

75

Alloy nanoparticle synthesis using ionizing radiation  

DOE Patents [OSTI]

A method of forming stable nanoparticles comprising substantially uniform alloys of metals. A high dose of ionizing radiation is used to generate high concentrations of solvated electrons and optionally radical reducing species that rapidly reduce a mixture of metal ion source species to form alloy nanoparticles. The method can make uniform alloy nanoparticles from normally immiscible metals by overcoming the thermodynamic limitations that would preferentially produce core-shell nanoparticles.

Nenoff, Tina M. (Sandia Park, NM); Powers, Dana A. (Albuquerque, NM); Zhang, Zhenyuan (Durham, NC)

2011-08-16T23:59:59.000Z

76

The multiphoton ionization of uranium hexafluoride  

SciTech Connect (OSTI)

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.)

1992-05-01T23:59:59.000Z

77

Schwinger Pair Production in Pulsed Electric Fields  

E-Print Network [OSTI]

We numerically investigate the temporal behavior and the structure of longitudinal momentum spectrum and the field polarity effect on pair production in pulsed electric fields in scalar quantum electrodynamics (QED). Using the evolution operator expressed in terms of the particle and antiparticle operators, we find the exact quantum states under the influence of electric pulses and measure the number of pairs of the Minkowski particle and antiparticle. The number of pairs, depending on the configuration of electric pulses, exhibits rich structures in the longitudinal momentum spectrum and undergoes diverse dynamical behaviors at the onset of the interaction but always either converges to a momentum-dependent constant or oscillates around a momentum-dependent time average after the completion of fields.

Sang Pyo Kim; Hyung Won Lee; Remo Ruffini

2012-07-22T23:59:59.000Z

78

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

79

Thermodynamics of pairing transition in hot nuclei  

E-Print Network [OSTI]

The pairing correlations in hot nuclei $^{162}$Dy are investigated in terms of the thermodynamical properties by covariant density functional theory. The heat capacities $C_V$ are evaluated in the canonical ensemble theory and the paring correlations are treated by a shell-model-like approach, in which the particle number is conserved exactly. A S-shaped heat capacity curve, which agrees qualitatively with the experimental data, has been obtained and analyzed in details. It is found that the one-pair-broken states play crucial roles in the appearance of the S shape of the heat capacity curve. Moreover, due to the effect of the particle-number conservation, the pairing gap varies smoothly with the temperature, which indicates a gradual transition from the superfluid to the normal state.

Lang Liu; Zhen-Hua Zhang; Peng-Wei Zhao

2014-12-16T23:59:59.000Z

80

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

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

Extracting an entangled photon pair from collectively decohered pairs at a telecommunication wavelength  

E-Print Network [OSTI]

We experimentally demonstrated entanglement extraction scheme by using photons at the telecommunication band for optical-fiber-based quantum communications. We generated two pairs of non-degenerate polarization entangled photons at 780~nm and 1551~nm by spontaneous parametric down-conversion and distributed the two photons at 1551~nm through a collective phase damping channel which gives the same amount of random phase shift on the two photons. Through local operation and classical communication, we extracted an entangled photon pair from two phase-disturbed photon pairs. An observed fidelity of the extracted photon pair to a maximally entangled photon pair was 0.73 $\\pm$ 0.07 which clearly shows the recovery of entanglement.

Yoshiaki Tsujimoto; Yukihiro Sugiura; Makoto Ando; Daisuke Katsuse; Rikizo Ikuta; Takashi Yamamoto; Masato Koashi; Nobuyuki Imoto

2015-03-10T23:59:59.000Z

82

Improved Modular Termination Proofs Using Dependency Pairs  

E-Print Network [OSTI]

Improved Modular Termination Proofs Using Dependency Pairs Renâ??e Thiemann, JË?urgen Giesl, Peter) termination proofs of term rewrite systems (TRSs). For any TRS, it generates inequality constraints that have to be satisfied by well­founded orders. However, proving innermost termination is considerably easier than

Kobbelt, Leif

83

Improved Modular Termination Proofs Using Dependency Pairs #  

E-Print Network [OSTI]

Improved Modular Termination Proofs Using Dependency Pairs # Renâ??e Thiemann, JË?urgen Giesl, Peter) termination proofs of term rewrite systems (TRSs). For any TRS, it generates inequality constraints that have to be satisfied by well­founded orders. However, proving innermost termination is considerably easier than

Ábrahám, Erika

84

Improved Modular Termination Proofs Using Dependency Pairs  

E-Print Network [OSTI]

Improved Modular Termination Proofs Using Dependency Pairs Ren´e Thiemann, J¨urgen Giesl, Peter) termination proofs of term rewrite systems (TRSs). For any TRS, it generates inequality constraints that have to be satisfied by well-founded orders. However, proving innermost termination is considerably easier than

Middeldorp, Aart

85

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

86

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

87

COOPER PAIR TRANSISTOR IN A TUNABLE ENVIRONMENT  

E-Print Network [OSTI]

COOPER PAIR TRANSISTOR IN A TUNABLE ENVIRONMENT S. Corlevi, W. Guichard, and D. B. Haviland* 1 measurements of the CPT, which are performed in a low impedance environment, the charging effects are observed as gate voltage modulation of the critical current. However, in a high impedance environment, a Coulomb

Haviland, David

88

EFFECT OF JOINT AUDITOR PAIR ON CONSERVATISM  

E-Print Network [OSTI]

1 EFFECT OF JOINT AUDITOR PAIR ON CONSERVATISM: EVIDENCE FROM IMPAIRMENT TESTS Gerald Lobo's (1997) measure of conservatism, are more likely to book impairments when operating performance is low requiring joint audit to improve audit quality. Mots clés : Co-commissariat ­ Reconnaissance adéquate des

Paris-Sud XI, Université de

89

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.

90

Resonance ionization detection of combustion radicals  

SciTech Connect (OSTI)

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

91

(Resonance ionization spectroscopy and its applications)  

SciTech Connect (OSTI)

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

92

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

93

Tissue Imaging Using Nanospray Desorption Electrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

We present the first results showing the ambient imaging of biological samples in their native environment using nanospray desorption ionization (nanoDESI) mass spectrometry. NanoDESI is an ambient pressure ionization technique that enables precise control of ionization of molecules from substrates. We demonstrate highly sensitive and robust analysis of tissue samples with high spatial resolution (<12 {mu}m) without sample preparation, which will be essential for applications in clinical diagnostics, drug discovery, molecular biology, and biochemistry.

Laskin, Julia; Heath, Brandi S.; Roach, Patrick J.; Cazares, Lisa H.; Semmes, O. John

2012-01-03T23:59:59.000Z

94

average ionization potential: Topics by E-print Network  

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

atomic and molecular hydrogen osmotic pressure which can drive a wind outward from the umbra. Ambipolar diffusion against the magnetically pinned ionized plasma component can also...

95

Ionization-induced effects in amorphous apatite at elevated temperatur...  

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

of the structural contrast features, respectively. Citation: Bae IT, Y Zhang, WJ Weber, M Ishimaru, Y Hirotsu, and M Higuchi.2008."Ionization-induced effects in amorphous...

96

atmospheric pressure ionization: Topics by E-print Network  

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

for Atmospheric Pressure, in Vivo, and Imaging Mass. For example, atmospheric pressure infrared MALDI (AP IR-MALDI), capable of producing ions from small ionization (DESI),5...

97

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

98

Ionized nebulae surrounding brightest cluster galaxies  

E-Print Network [OSTI]

We present IFU observations of six emission-line nebulae that surround the central galaxy of cool core clusters. Qualitatively similar nebulae are observed in cool core clusters even when the dynamics and possibly formation and excitation source are different. Evidence for a nearby secondary galaxy disturbing a nebula, as well as AGN and starburst driven outflows are presented as possible formation mechanisms. One nebula has a rotation velocity of the same amplitude as the underlying molecular reservoir, which implies that the excitation or formation of a nebula does not require any disturbance of the molecular reservoir within the central galaxy. Bulk flows and velocity shears of a few hundred km/s are seen across all nebulae. The majority lack any ordered rotation, their configurations are not stable so the nebulae must be constantly reshaping, dispersing and reforming. The dimmer nebulae are co-spatial with dust features whilst the more luminous are not. Significant variation in the ionization state of the gas is seen in all nebulae through the non-uniform [NII]/H_alpha ratio. There is no correlation between the line ratio and H_alpha surface brightness, but regions with excess blue or UV light have lower line ratios. This implies that UV from massive, young stars act in combination with an underlying heating source that produces the observed low-ionization spectra.

N. A. Hatch; C. S. Crawford; A. C. Fabian

2007-06-05T23:59:59.000Z

99

IONIZED OUTFLOWS FROM COMPACT STEEP SPECTRUM SOURCES  

SciTech Connect (OSTI)

Massive outflows are known to exist, in the form of extended emission-line regions (EELRs), around about one-third of powerful FR II radio sources. We investigate the origin of these EELRs by studying the emission-line regions around compact-steep-spectrum (CSS) radio galaxies that are younger (10{sup 3}-10{sup 5} yr old) versions of the FR II radio galaxies. We have searched for and analyzed the emission-line regions around 11 CSS sources by taking integral field spectra using Gemini Multi-Object Spectrograph on Gemini North. We fit the [O III] {lambda}5007 line and present the velocity maps for each detected emission-line region. We find, in most cases, that the emission-line regions have multi-component velocity structures with different velocity dispersions and/or flux distributions for each component. The velocity gradients of the emission-line gas are mostly well aligned with the radio axis, suggesting a direct causal link between the outflowing gas and the radio jets. The complex velocity structure may be a result of different driving mechanisms related to the onset of the radio jets. We also present the results from the line-ratio diagnostics we used to analyze the ionization mechanism of the extended gas, which supports the scenario where the emission-line regions are ionized by a combination of active galactic nucleus radiation and shock excitation.

Shih, Hsin-Yi; Stockton, Alan; Kewley, Lisa, E-mail: hsshih@ifa.hawaii.edu, E-mail: stockton@ifa.hawaii.edu, E-mail: lisa.kewley@anu.edu.au [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

2013-08-01T23:59:59.000Z

100

A search for resonant Z pair production  

SciTech Connect (OSTI)

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

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

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

102

Pair densities in density functional theory  

E-Print Network [OSTI]

The exact interaction energy of a many-electron system is determined by the electron pair density, which is not well-approximated in standard Kohn-Sham density functional models. Here we study the (complicated but well-defined) exact universal map from density to pair density. We show that many common functionals, including the most basic version of the LDA (Dirac exchange with no correlation contribution), arise from particular approximations of this map. We develop an algorithm to compute the map numerically, and apply it to one-parameter families {a*rho(a*x)} of one-dimensional homogeneous and inhomogeneous single-particle densities. We observe that the pair density develops remarkable multiscale patterns which strongly depend on both the particle number and the "width" 1/a of the single-particle density. The simulation results are confirmed by rigorous asymptotic results in the limiting regimes a>>1 and a<<1. For one-dimensional homogeneous systems, we show that the whole spectrum of patterns is rep...

Chen, Huajie

2015-01-01T23:59:59.000Z

103

Cluster virial expansion for the equation of state of partially ionized hydrogen plasma  

SciTech Connect (OSTI)

We study the contribution of electron-atom interaction to the equation of state for partially ionized hydrogen plasma using the cluster-virial expansion. We use the Beth-Uhlenbeck approach to calculate the second virial coefficient for the electron-atom (bound cluster) pair from the corresponding scattering phase shifts and binding energies. Experimental scattering cross-sections as well as phase shifts calculated on the basis of different pseudopotential models are used as an input for the Beth-Uhlenbeck formula. By including Pauli blocking and screening in the phase shift calculation, we generalize the cluster-virial expansion in order to cover also near solid density plasmas. We present results for the electron-atom contribution to the virial expansion and the corresponding equation of state, i.e. pressure, composition, and chemical potential as a function of density and temperature. These results are compared with semiempirical approaches to the thermodynamics of partially ionized plasmas. Avoiding any ill-founded input quantities, the Beth-Uhlenbeck second virial coefficient for the electron-atom interaction represents a benchmark for other, semiempirical approaches.

Omarbakiyeva, Y. A. [Institute of Physics, University of Rostock, D-18051 Rostock (Germany); IETP, Al-Farabi Kazakh National University, 96a, Tole bi St., Almaty 050012 (Kazakhstan); Fortmann, C. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095 (United States); Ramazanov, T. S. [IETP, Al-Farabi Kazakh National University, 96a, Tole bi St., Almaty 050012 (Kazakhstan); Roepke, G. [Institute of Physics, University of Rostock, D-18051 Rostock (Germany)

2010-08-15T23:59:59.000Z

104

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

SciTech Connect (OSTI)

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

105

Optical absorption and ionization of silicate glasses Leonid B. Glebov  

E-Print Network [OSTI]

Optical absorption and ionization of silicate glasses Leonid B. Glebov School of Optics and hydroxyl), and induced (color centers) absorption of multicomponent silicate glasses in UV, visible-photon ionization was detected in alkaline-silicate glasses exposed to high-power laser radiation in nano

Glebov, Leon

106

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

107

Laser plasma formation assisted by ultraviolet pre-ionization  

SciTech Connect (OSTI)

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

108

Energy Efficiency and Fitness - A Complementary Pair | Department...  

Broader source: Energy.gov (indexed) [DOE]

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 Former Digital...

109

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

110

E-Print Network 3.0 - ambient ionization source Sample Search...  

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

Summary: ionization present due to ambient sources such as radioactive materials in buildings, see discussion... be an efficient source of ionization ahead of a streamer, but...

111

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

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

112

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

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

113

Plasmadynamics and ionization kinetics of thermionic energy conversion  

SciTech Connect (OSTI)

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

114

Practical calculation of amplitudes for electron-impact ionization  

SciTech Connect (OSTI)

An integral expression that is formally valid only for short-range potentials is applied to the problem of calculating the amplitude for electron-impact ionization. It is found that this expression provides a practical and accurate path to the calculation of singly differential cross sections for electron-impact ionization. Calculations are presented for the Temkin-Poet and collinear models for ionization of hydrogen by electron impact. An extension of the finite-element approach using the discrete-variable representation, appropriate for potentials with discontinuous derivatives like the Temkin-Poet interaction, is also presented.

McCurdy, C. William; Horner, Daniel A.; Rescigno, Thomas N.

2001-02-01T23:59:59.000Z

115

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

116

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

117

Ionizing radiation effects on silicon test structures  

SciTech Connect (OSTI)

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

118

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

119

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

SciTech Connect (OSTI)

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

120

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 (OSTI)

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

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

Pair Correlation Function of Wilson Loops  

E-Print Network [OSTI]

We give a path integral prescription for the pair correlation function of Wilson loops lying in the worldvolume of Dbranes in the bosonic open and closed string theory. The results can be applied both in ordinary flat spacetime in the critical dimension d or in the presence of a generic background for the Liouville field. We compute the potential between heavy nonrelativistic sources in an abelian gauge theory in relative collinear motion with velocity v = tanh(u), probing length scales down to r_min^2 = 2 \\pi \\alpha' u. We predict a universal -(d-2)/r static interaction at short distances. We show that the velocity dependent corrections to the short distance potential in the bosonic string take the form of an infinite power series in the dimensionless variables z = r_min^2/r^2, uz/\\pi, and u^2.

S. Chaudhuri; Y. Chen; E. Novak

2000-02-02T23:59:59.000Z

122

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

123

Research paper Drug diffusion and binding in ionizable interpenetrating networks  

E-Print Network [OSTI]

Research paper Drug diffusion and binding in ionizable interpenetrating networks from poly) (PVA), poly(acrylic acid) (PAA), and their interpenetrating networks (IPNs) were prepared using by measuring their equilibrium polymer volume fraction, equilibrium swelling ratio, and mesh size. Drug

Peppas, Nicholas A.

124

argon ionization detector: Topics by E-print Network  

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

Goeldi; S. Janos; I. Kreslo; M. Luethi; C. Rudolf von Rohr; T. Strauss; T. Tolba; M. S. Weber 2014-06-16 5 A method to suppress dielectric breakdowns in liquid argon ionization...

125

ammonia chemical ionization: Topics by E-print Network  

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

ionization processes (more) Ozawa, Takashi 2007-01-01 69 Energy Savings from Floating Head Pressure in Ammonia Refrigeration Systems Texas A&M University - TxSpace Summary:...

126

Rules and Regulations for Control of Ionizing Radiation (Arkansas)  

Broader source: Energy.gov [DOE]

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...

127

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.

128

Ionization by few-cycle pulses: Tracing the electron orbits  

SciTech Connect (OSTI)

High-order above-threshold ionization by few-cycle laser pulses is analyzed in terms of quantum orbits. For a given carrier-envelope phase, the number of contributing orbits and their ionization and rescattering times determine the shape of the angle-resolved spectrum in all detail. Conversely, analysis of a given spectrum reveals the carrier-envelope phase and the various interfering pathways from which the electron could choose.

Milosevic, D.B. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo (Bosnia and Herzegowina); Paulus, G.G. [Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Becker, W. [Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin (Germany)

2005-06-15T23:59:59.000Z

129

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

130

ALFVEN WAVES IN A PARTIALLY IONIZED TWO-FLUID PLASMA  

SciTech Connect (OSTI)

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

131

High pressure argon ionization chamber systems for the measurement of environmental radiation exposure rates  

E-Print Network [OSTI]

High pressure argon ionization chamber systems for the measurement of environmental radiation exposure rates

DeCampo, J A; Raft, P D

1972-01-01T23:59:59.000Z

132

On the polar cap cascade pair multiplicity of young pulsars  

E-Print Network [OSTI]

We study the efficiency of pair production in polar caps of young pulsars under a variety of conditions to estimate the maximum possible multiplicity of pair plasma in pulsar magnetospheres. We develop a semi-analytic model for calculation of cascade multiplicity which allows efficient exploration of the parameter space and corroborate it with direct numerical simulations. Pair creation processes are considered separately from particle acceleration in order to assess different factors affecting cascade efficiency, with acceleration of primary particles described by recent self-consistent non-stationary model of pair cascades. We argue that the most efficient cascades operate in the curvature radiation/synchrotron regime, the maximum multiplicity of pair plasma in pulsar magnetospheres is ~few x 10^5. The multiplicity of pair plasma in magnetospheres of young energetic pulsars weakly depends on the strength of the magnetic field and the radius of curvature of magnetic field lines and has a stronger dependence ...

Timokhin, A N

2015-01-01T23:59:59.000Z

133

Isovector pairing and quartet condensation in N=Z nuclei  

SciTech Connect (OSTI)

We introduce and study a quartet condensate model (QCM) to treat the isovector pairing correlations in N=Z nuclei, by conserving the particle number and the total spin and isospin in the ground state of such nuclei. For the calculations we choose different isovector pairing forces acting on spherical and axially deformed single particle states. The results show that the QCM model describes very well the isovector pairing correlations for nuclear systems with N=Z.

Sandulescu, N.; Negrea, D.; Dukelsky, J.; Johnson, C. W. [National Institute of Physics and Nuclear Engineering, P.O. BOX MG-6, 76900 Bucharest-Magurele (Romania); Instituto de Estructura de la Materia, CSIC, Serrano 123, 28006 Madrid (Spain); Department of Physics, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182-1233 (United States)

2012-11-20T23:59:59.000Z

134

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

135

Proton-neutron pairing correlations in the nuclear shell model  

E-Print Network [OSTI]

A shell-model study of proton-neutron pairing in f - p shell nuclei using a parametrized hamiltonian that includes deformation and spin-orbit effects as well as isoscalar and isovector pairing is reported. By working in a shell-model framework we are able to assess the role of the various modes of proton-neutron pairing in the presence of nuclear deformation without violating symmetries. Results are presented for $^{44}$Ti, $^{46}$Ti and $^{48}$Cr.

Lei Yang; S. Pittel; B. Thakur; N. Sandulescu; A. Poves; Yu-Min Zhao

2010-06-16T23:59:59.000Z

136

A Bell pair in a generic random matrix environment  

E-Print Network [OSTI]

Two non-interacting qubits are coupled to an environment. Both coupling and environment are represented by random matrix ensembles. The initial state of the pair is a Bell state, though we also consider arbitrary pure states. Decoherence of the pair is evaluated analytically in terms of purity; Monte Carlo calculations confirm these results and also yield the concurrence of the pair. Entanglement within the pair accelerates decoherence. Numerics display the relation between concurrence and purity known for Werner states, allowing us to give a formula for concurrence decay.

Carlos Pineda; Thomas H. Seligman

2006-05-18T23:59:59.000Z

137

associative pairing enhances: Topics by E-print Network  

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

design rules... Cowen, Nicholas L. 2010-07-14 22 Associated Production of Neutral Higgs Boson with Squark Pair in the Minimal Supersymmetric Standard Model with Explicit CP...

138

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

139

Plasmadynamics and ionization kinetics of thermionic energy conversion  

SciTech Connect (OSTI)

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

140

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.

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

Beam Head Erosion in Self-Ionized Plasma Wakefield Accelerators  

SciTech Connect (OSTI)

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

142

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

143

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

144

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

145

Pair Production of Topological anti de Sitter Black Holes  

E-Print Network [OSTI]

The pair creation of black holes with event horizons of non-trivial topology is described. The spacetimes are all limiting cases of the cosmological $C$ metric. They are generalizations of the $(2+1)$ dimensional black hole and have asymptotically anti de Sitter behaviour. Domain walls instantons can mediate their pair creation for a wide range of mass and charge.

R. B. Mann

1996-07-28T23:59:59.000Z

146

Density-matrix functionals for pairing in mesoscopic superconductors  

E-Print Network [OSTI]

A functional theory based on single-particle occupation numbers is developed for pairing. This functional, that generalizes the BCS 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.

Denis Lacroix; Guillaume Hupin

2010-09-03T23:59:59.000Z

147

Semiclassical pair production rate for rotating electric fields  

E-Print Network [OSTI]

We semiclassically investigate Schwinger pair production for pulsed rotating electric fields depending on time. To do so we solve the Dirac equation for two-component fields in a WKB-like approximation. The result shows that for two-component fields the spin distribution of produced pairs is generally not $1:1$. As a result the pair creation rates of spinor and scalar quantum electro dynamics (QED) are different even for one pair of turning points. For rotating electric fields the pair creation rate is dominated by particles with a specific spin depending on the sense of rotation for a certain range of pulse lengths and frequencies. We present an analytical solution for the momentum spectrum of the constant rotating field. We find interference effects not only in the momentum spectrum but also in the total particle number of rotating electric fields.

Eckhard Strobel; She-Sheng Xue

2015-02-09T23:59:59.000Z

148

Relativistic tunneling picture of electron-positron pair creation  

E-Print Network [OSTI]

The common tunneling picture of electron-positron pair creation in a strong electric field is generalized to pair creation in combined crossed electric and magnetic fields. This enhanced picture, being symmetric for electrons and positrons, is formulated in a gauge-invariant and Lorentz-invariant manner for quasistatic fields. It may be used to infer qualitative features of the pair creation process. In particular, it allows for an intuitive interpretation of how the presence of a magnetic field modifies and, in particular cases, even enhances pair creation. The creation of electrons and positrons from the vacuum may be assisted by an energetic photon, which can also be incorporated into this picture of pair creation.

Anton Wöllert; Michael Klaiber; Heiko Bauke; Christoph H. Keitel

2015-03-19T23:59:59.000Z

149

Spatially resolved thermal desorption/ionization coupled with mass spectrometry  

DOE Patents [OSTI]

A system and method for sub-micron analysis of a chemical composition of a specimen are described. The method includes providing a specimen for evaluation and a thermal desorption probe, thermally desorbing an analyte from a target site of said specimen using the thermally active tip to form a gaseous analyte, ionizing the gaseous analyte to form an ionized analyte, and analyzing a chemical composition of the ionized analyte. The thermally desorbing step can include heating said thermally active tip to above 200.degree. C., and positioning the target site and the thermally active tip such that the heating step forms the gaseous analyte. The thermal desorption probe can include a thermally active tip extending from a cantilever body and an apex of the thermally active tip can have a radius of 250 nm or less.

Jesse, Stephen; Van Berkel, Gary J; Ovchinnikova, Olga S

2013-02-26T23:59:59.000Z

150

Narrow escape: how ionizing photons escape from disc galaxies  

E-Print Network [OSTI]

In this paper we calculate the escape fraction ($f_{\\rm esc}$) of ionizing photons from starburst galaxies. Using 2-D axisymmetric hydrodynamic simulations, we study superbubbles created by overlapping supernovae in OB associations. We calculate the escape fraction of ionizing photons from the center of the disk along different angles through the superbubble and the gas disk. After convolving with the luminosity function of OB associations, we show that the ionizing photons escape within a cone of $\\sim 40 ^\\circ$, consistent with observations of nearby galaxies. The evolution of the escape fraction with time shows that it falls initially as cold gas is accumulated in a dense shell. After the shell crosses a few scale heights and fragments, the escape fraction through the polar regions rises again. The angle-averaged escape fraction cannot exceed $\\sim [1- \\cos (1 \\, {\\rm radian})] = 0.5$ from geometrical considerations (using the emission cone opening angle). We calculate the dependence of the time- and angl...

Roy, Arpita; Sharma, Prateek

2014-01-01T23:59:59.000Z

151

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

SciTech Connect (OSTI)

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

152

Direct measurements of the ionization profile in krypton helicon plasmas  

SciTech Connect (OSTI)

Helicons are efficient plasma sources, capable of producing plasma densities of 10{sup 19} m{sup -3} with only 100 s W of input rf power. There are often steep density gradients in both the neutral density and plasma density, resulting in a fully ionized core a few cm wide surrounded by a weakly ionized plasma. The ionization profile is usually not well known because the neutral density is typically inferred from indirect spectroscopic measurements or from edge pressure gauge measurements. We have developed a two photon absorption laser induced fluorescence (TALIF) diagnostic capable of directly measuring the neutral density profile. We use TALIF in conjunction with a Langmuir probe to measure the ionization fraction profile as a function of driving frequency, magnetic field, and input power. It is found that when the frequency of the driving wave is greater than a critical frequency, f{sub c} Almost-Equal-To 3f{sub lh}, where f{sub lh} is the lower hybrid frequency at the antenna, the ionization fraction is small (0.1%) and the plasma density low (10{sup 17} m{sup -3}). As the axial magnetic field is increased, or, equivalently, the driving frequency decreased, a transition is observed. The plasma density increases by a factor of 10 or more, the plasma density profile becomes strongly peaked, the neutral density profile becomes strongly hollow, and the ionization fraction in the core approaches 100%. Neutral depletion in the core can be caused by a number of mechanisms. We find that in these experiments the depletion is due primarily to plasma pressure and neutral pumping.

Magee, R. M.; Galante, M. E.; McCarren, D. W.; Scime, E. E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States); Gulbrandsen, N. [Department of Physics and Technology, Faculty of Science, University of Tromso, N-9037 Tromso (Norway)

2012-12-15T23:59:59.000Z

153

Diffuse Gas Condensation Induced by Variations of the Ionizing Flux  

E-Print Network [OSTI]

The variation of an ionizing flux as a mechanism to stimulate the condensation of a diffuse gas is considered. To illustrate this effect, two situations are examined: one on the context of pregalactic conditions, and the other on the context of the actual interstellar medium. We focus our attention on flash-like variations; that is, during a ``short'' period of time the ionizing flux is enhanced in comparison to the pre- and post-flash values. In both cases the cause of the induced phase change is the same: the enhancement of the cooling rate by the increase in the electron density caused by the momentary increase of ionizing flux. After the passing of the flash, the cooling rate remains enhanced due to the ``inertia of the ionization''. In the first case (metal free gas) the cooling rate is enhanced due to the fact that the increase of the electron density makes possible the gas phase formation of H_2 by the creation of the intermediaries H^- and H^+_2. We show that after the passing of the photo-ionizing flash a cloud near thermo-chemical equilibrium at ~8000 K may be induced to increase its H_2 content by many orders of magnitude, causing a rapid decrease of its temperature to values as low as 100 K. In the second case (solar abundances gas) the dominant cooling mechanism of the warm neutral gas (the excitation of heavy ions by electron impacts) is proportional to the electron density. We show that, for the expected states of the warm interstellar gas, ionizing flashes may induce the phase transition from the warm to the cool phase. The results indicate that the mechanism of induced condensation studied here might play a relevant role in the gas evolution of the diffuse gas in both, the pregalactic and the actual interstellar medium conditions.

Antonio Parravano; Catherine Pech

1997-07-31T23:59:59.000Z

154

Closed-loop control of ionization oscillations in Hall accelerators  

SciTech Connect (OSTI)

Feedback control of ionization oscillations in Hall accelerators is investigated with a proportional-integral-derivative controller acting on the discharge voltage. The stability of the current is found to systematically improve with proportional control, whereas integral and derivative control have in most cases a detrimental or insignificant impact. At low discharge voltages, proportional control eliminates at the same time ionization breathing oscillations as well as a coexisting low frequency mode. A progressive deterioration of the stability is observed at higher voltage, presumably attributable to the limited output voltage range of the controller. The time-averaged characteristics of the discharge such as average current, thrust and efficiency, remain unchanged within measurement uncertainties.

Barral, S.; Kaczmarczyk, J.; Kurzyna, J. [Institute of Plasma Physics and Laser Microfusion, 01497 Warsaw (Poland); Dudeck, M. [Universite Pierre et Marie Curie, Institut Jean Le Rond d'Alembert, 75252 Paris (France)

2011-08-15T23:59:59.000Z

155

Increased Upstream Ionization due to Formation of a Double Layer  

SciTech Connect (OSTI)

We report observations that confirm a theoretical prediction that formation of a current-free double layer in a plasma expanding into a chamber of larger diameter is accompanied by an increase in ionization upstream of the double layer. The theoretical model argues that the increased ionization is needed to balance the difference in diffusive losses upstream and downstream of the expansion region. In our expanding helicon source experiments, we find that the upstream plasma density increases sharply at the same antenna frequency at which the double layer appears.

Thakur, S. Chakraborty; Harvey, Z.; Biloiu, I. A.; Hansen, A.; Hardin, R. A.; Przybysz, W. S.; Scime, E. E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States)

2009-01-23T23:59:59.000Z

156

Electronic structure and spectroscopy of nucleic acid bases: Ionization energies, ionization-induced structural changes, and photoelectron spectra  

SciTech Connect (OSTI)

We report high-level ab initio calculations and single-photon ionization mass spectrometry study of ionization of adenine (A), thymine (T), cytosine (C) and guanine (G). For thymine and adenine, only the lowest-energy tautomers were considered, whereas for cytosine and guanine we characterized five lowest-energy tautomeric forms. The first adiabatic and several vertical ionization energies were computed using equation-of-motion coupled-cluster method for ionization potentials with single and double substitutions. Equilibrium structures of the cationic ground states were characterized by DFT with the {omega}B97X-D functional. The ionization-induced geometry changes of the bases are consistent with the shapes of the corresponding molecular orbitals. For the lowest-energy tautomers, the magnitude of the structural relaxation decreases in the following series G > C > A > T, the respective relaxation energies being 0.41, 0.32, 0.25 and 0.20 eV. The computed adiabatic ionization energies (8.13, 8.89, 8.51-8.67 and 7.75-7.87 eV for A,T,C and G, respectively) agree well with the onsets of the photoionization efficiency (PIE) curves (8.20 {+-} 0.05, 8.95 {+-} 0.05, 8.60 {+-} 0.05 and 7.75 {+-} 0.05 eV). Vibrational progressions for the S{sub 0}-D{sub 0} vibronic bands computed within double-harmonic approximation with Duschinsky rotations are compared with previously reported experimental photoelectron spectra.

Bravaya, Ksenia B.; Kostko, Oleg; Dolgikh, Stanislav; Landau, Arie; Ahmed, Musahid; Krylov, Anna I.

2010-08-02T23:59:59.000Z

157

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

158

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

159

QED peripheral mechanism of pair production at colliders  

SciTech Connect (OSTI)

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

160

Validity of pair truncations with effective interaction in Ca isotopes  

SciTech Connect (OSTI)

Using the GXPF1A interaction for the pf shell nuclei, we calculate energy levels and E2 transition rates for the semimagic nuclei {sup 43-46}Ca within both the exact shell-model space and a number of subspaces constructed using collective nucleon pairs. We present explicitly the overlaps between wave functions of low-lying states obtained from shell-model calculations and those obtained using truncated nucleon-pair subspaces. These examples are used as touchstones of pair approximations.

Lei, Y.; Xu, Z. Y. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhao, Y. M. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China); Arima, A. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Science Museum, Japan Science Foundation, 2-1 Kitanomaru-koen, Chiyoda ku, Tokyo 102-0091 (Japan)

2010-09-15T23:59:59.000Z

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.


161

Effective field theory for dilute fermions with pairing  

SciTech Connect (OSTI)

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

162

The Electrical Conductivity Of Partly Ionized Helium Plasma  

SciTech Connect (OSTI)

In this paper we analyzed atoms influence on electro conductivity, partially ionized helium plasma, in temperature region 5 000 K - 40 000 K and pressure 0.1 - 10 atm. Electro conductivity was calculated using 'Frost like' formula and Random Phase Approximation method and Semi-Classical (SC) approximation.

Sreckovic, Vladimir A.; Ignjatovic, Ljubinko; Mihajlov, A. A. [Institute of Physics, PO Box 57, 11001 Belgrade (Serbia and Montenegro)

2007-04-23T23:59:59.000Z

163

Ionization distances of multiply charged Rydberg ions approaching solid surfaces  

SciTech Connect (OSTI)

The ionization distances R{sub c}{sup I} as well as the ionization rates and eigenenergies of one-electron multiply charged Rydberg ions (core charge Z>>1, principal quantum number n>>1) approaching solid surfaces are calculated. Within the framework of a nonperturbative etalon equation method (EEM), these quantities are obtained simultaneously. The complex energy eigenvalue problem for the decaying eigenstates is solved within the critical region R{approx_equal}R{sub c}{approx_equal}R{sub c}{sup I} of the ion-surface distances R. This region is characterized by the energy terms localized in the vicinity of the top of an effective potential barrier, created between the ion and polarized solid. We take into account that the parabolic symmetry is preserved for R{approx_equal}R{sub c} and that the parabolic quantum numbers can be taken as approximate but sufficiently good quantum numbers. The parabolic rates, energies, and corresponding ionization distances are presented in relatively simple analytical forms. The ionization distances are compared with the results of a classical overbarrier model. Comparison of the obtained energies and rates with the available theoretical predictions of the coupled angular mode method shows good agreement. The use of the EEM for an estimation of the upper limit of the first neutralization distance in the subsequent neutralization cascade is briefly discussed.

Nedeljkovic, Lj. D.; Nedeljkovic, N. N.; Bozanic, D. K. [Faculty of Physics, University of Belgrade, P.O. Box 368, Belgrade (Serbia and Montenegro); Vinca Institute of Nuclear Sciences, P.O. Box 522, Belgrade (Serbia and Montenegro)

2006-09-15T23:59:59.000Z

164

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

165

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

166

The Metagalactic Ionizing Field in the Local Group  

E-Print Network [OSTI]

We discuss the sources which are likely to dominate the ionizing field throughout the Local Group. In terms of the limiting flux to produce detectable H-alpha emission (4-10 x 10**3 phot/cm**2/s), the four dominant galaxies (M31, Galaxy, M33, LMC) have spheres of influence which occupy a small fraction (<10%) of the Local Volume. There are at least two possible sources of ionization whose influence could be far more pervasive: (i) a cosmic background of ionizing photons; (ii) a pervasive warm plasma throughout the Local Group. The COBE FIRAS sky temperature measurements permit a wide variety of plasmas with detectable ionizing fields. It has been suggested (Blitz et al. 1996; Spergel et al. 1996; Sembach et al. 1995, 1998) that a substantial fraction of high velocity clouds are external to the Galaxy but within the Local Group. Deep H-alpha detections are the crucial test of these claims and, indeed, provide a test bed for the putative Local Group corona.

J. Bland-Hawthorn

1998-06-23T23:59:59.000Z

167

Ionization Thresholds of Small Carbon Clusters: Tunable VUVExperiments and Theory  

SciTech Connect (OSTI)

Small carbon clusters (Cn, n = 2-15) are produced in amolecular beam by pulsed laser vaporization and studied with vacuumultraviolet (VUV) photoionization mass spectrometry. The required VUVradiation in the 8-12 eV range is provided by the Advanced Light Source(ALS) at the Lawrence Berkeley National Laboratory. Mass spectra atvarious ionization energies reveal the qualitative relative abundances ofthe neutral carbon clusters produced. By far the most abundant species isC3. Using the tunability of the ALS, ionization threshold spectra arerecorded for the clusters up to 15 atoms in size. The ionizationthresholds are compared to those measured previously with charge-transferbracketing methods. To interpret the ionization thresholds for differentcluster sizes, new ab initio calculations are carried out on the clustersfor n = 4-10. Geometric structures are optimized at the CCSD(T) levelwith cc-pVTZ (or cc-pVDZ) basis sets, and focal point extrapolations areapplied to both neutral and cation species to determine adiabatic andvertical ionization potentials. The comparison of computed and measuredionization potentials makes it possible to investigate the isomericstructures of the neutral clusters produced in this experiment. Themeasurements are inconclusive for the n = 4-6 species because ofunquenched excited electronic states. However, the data provide evidencefor the prominence of linear structures for the n = 7, 9, 11, 13 speciesand the presence of cyclic C10.

Belau, Leonid; Wheeler, Steven E.; Ticknor, Brian W.; Ahmed,Musahid; Leone, Stephen R.; Allen, Wesley D.; Schaefer III, Henry F.; Duncan, Michael A.

2007-07-31T23:59:59.000Z

168

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

169

Perturbations of ionization fractions at the cosmological recombination epoch  

E-Print Network [OSTI]

A development of perturbations of number densities of ions and electrons during recombination epoch is analysed. The equations for relative perturbations of ionization fractions were derived from the system of equations for accurate computation of the ionization history of the early Universe given by Seager et al. (1999,2000). It is shown that strong dependence of ionization and recombination rates on the density and temperature of plasma provides the significant deviations of amplitudes of ionization fractions relative perturbations from ones of baryon matter density adiabatic perturbations. Such deviations are most prominent for cosmological adiabatic perturbations of scales larger than sound horizon at recombination epoch. The amplitudes of relative perturbations of number densities of electrons and protons at last scattering surface exceed by factor of $\\simeq$5 the amplitude of relative perturbation of baryons total number density, for helium ions this ratio reaches the value of $\\simeq$18. For subhorizon cosmological perturbations these ratios appear to be essentially lesser and depend on oscillation phase at the moment of decoupling. These perturbations of number densities of ions and electrons at recombination epoch do not contribute to the intrinsic plasma temperature fluctuations but cause the ''corrugation'' of last scattering surface in optical depth, $\\delta z_{dec}/(z_{dec}+1)\\approx -\\delta_b/3$, at scales larger than sound horizon. It may result into noticeable changes of precalculated values of CMB polarization pattern at several degrees angular scales.

B. Novosyadlyj

2006-05-25T23:59:59.000Z

170

Constraints on the ionizing flux emitted by T Tauri stars  

E-Print Network [OSTI]

We present the results of an analysis of ultraviolet observations of T Tauri Stars (TTS). By analysing emission measures taken from the literature we derive rates of ionizing photons from the chromospheres of 5 classical TTS in the range ~10^41-10^44 photons/s, although these values are subject to large uncertainties. We propose that the HeII/CIV line ratio can be used as a reddening-independent indicator of the hardness of the ultraviolet spectrum emitted by TTS. By studying this line ratio in a much larger sample of objects we find evidence for an ionizing flux which does not decrease, and may even increase, as TTS evolve. This implies that a significant fraction of the ionizing flux from TTS is not powered by the accretion of disc material onto the central object, and we discuss the significance of this result and its implications for models of disc evolution. The presence of a significant ionizing flux in the later stages of circumstellar disc evolution provides an important new constraint on disc photoevaporation models.

R. D. Alexander; C. J. Clarke; J. E. Pringle

2005-01-06T23:59:59.000Z

171

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

172

condmat/0506136 IONIZATION BY IMPACT ELECTRONS IN SOLIDS  

E-Print Network [OSTI]

for impact ionizations is essential for investigating the radiation damage by energetic photons in solids­ray irradiation has become of significant interest to the research community. Radiation damage is the limiting or with the more accurate optical mod­ els based on the free­electron­gas approximation 5, 6 , and at very low

173

E-Print Network 3.0 - ablation electrospray ionization Sample...  

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

-assisted laser desorption ionization (MALDI)-MS24 and electrospray ionization (ESI)-MS.5,6 How- ever, samples... for the high-density emitter array. We showed that...

174

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

175

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

176

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

177

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

178

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

179

Cross Sections for Inner-Shell Ionization by Electron Impact  

SciTech Connect (OSTI)

An analysis is presented of measured and calculated cross sections for inner-shell ionization by electron impact. We describe the essentials of classical and semiclassical models and of quantum approximations for computing ionization cross sections. The emphasis is on the recent formulation of the distorted-wave Born approximation by Bote and Salvat [Phys. Rev. A 77, 042701 (2008)] that has been used to generate an extensive database of cross sections for the ionization of the K shell and the L and M subshells of all elements from hydrogen to einsteinium (Z = 1 to Z = 99) by electrons and positrons with kinetic energies up to 1 GeV. We describe a systematic method for evaluating cross sections for emission of x rays and Auger electrons based on atomic transition probabilities from the Evaluated Atomic Data Library of Perkins et al. [Lawrence Livermore National Laboratory, UCRL-ID-50400, 1991]. We made an extensive comparison of measured K-shell, L-subshell, and M-subshell ionization cross sections and of L? x-ray production cross sections with the corresponding calculated cross sections. We identified elements for which there were at least three (for K shells) or two (for L and M subshells) mutually consistent sets of cross-section measurements and for which the cross sections varied with energy as expected by theory. The overall average root-mean-square deviation between the measured and calculated cross sections was 10.9% and the overall average deviation was ?2.5%. This degree of agreement between measured and calculated ionization and x-ray production cross sections was considered to be very satisfactory given the difficulties of these measurements.

Llovet, Xavier, E-mail: xavier@ccit.ub.edu [Centres Científics i Tecnològics, Universitat de Barcelona, Lluís Solé i Sabarís 1-3, 08028 Barcelona (Spain)] [Centres Científics i Tecnològics, Universitat de Barcelona, Lluís Solé i Sabarís 1-3, 08028 Barcelona (Spain); Powell, Cedric J. [Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8370 (United States)] [Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8370 (United States); Salvat, Francesc [Facultat de Física (ECM and ICC), Universitat de Barcelona, Diagonal 645, 08028 Barcelona (Spain)] [Facultat de Física (ECM and ICC), Universitat de Barcelona, Diagonal 645, 08028 Barcelona (Spain); Jablonski, Aleksander [Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224 Warsaw (Poland)] [Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224 Warsaw (Poland)

2014-03-15T23:59:59.000Z

180

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

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

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

182

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

183

On magnon mediated Cooper pair formation in ferromagnetic superconductors  

SciTech Connect (OSTI)

Identification of pairing mechanism leading to ferromagnetic superconductivity is one of the most challenging issues in condensed matter physics. Although different models have been proposed to explain this phenomenon, a quantitative understanding about this pairing is yet to be achieved. Using the localized-itinerant model, we find that in ferromagnetic superconducting materials both triplet pairing and singlet pairing of electrons are possible through magnon exchange depending upon whether the Debye cut off frequency of magnons is greater or lesser than the Hund's coupling (J) multiplied by average spin (S) per site. Taking into account the repulsive interaction due to the existence of paramagnons, we also find an expression for effective interaction potential between a pair of electrons with opposite spins. We apply the developed formalism in case of UGe{sub 2} and URhGe. The condition of singlet pairing is found to be fulfilled in these cases, as was previously envisaged by Suhl [Suhl, Phys. Rev. Lett. 87, 167007 (2001)]. We compute the critical temperatures of URhGe at ambient pressure and of UGe{sub 2} under different pressures for the first time through BCS equation. Thus, this work outlines a very simple way to evaluate critical temperature in case of a superconducting system. A close match with the available experimental results strongly supports our theoretical treatment.

Kar, Rakesh; Paul, Bikash Chandra [Department of Physics, University of North Bengal, Raja Rammohunpur, Darjeeling 734013, West Bengal (India); Goswami, Tamal; Misra, Anirban, E-mail: anirbanmisra@yahoo.com [Department of Chemistry, University of North Bengal, Raja Rammohunpur, Darjeeling 734013, West Bengal (India)

2014-08-15T23:59:59.000Z

184

QSO pairs {\\it across} Active galaxies: Evidence of Blueshifts?  

E-Print Network [OSTI]

Several QSO pairs have been reported and their redshifts determined, where the two objects in each pair are located {\\it across} an active galaxy. The usually accepted explanation of such occurrences is that the pair is ejected from the active galaxy. Currebtly interpreted redshifted spectra for both the QSOs imply that both the objects are receding from the observer. However, ejection can occur towards and away from the observer with equal probability. We argue that for a system with two QSOs {\\it across} the parent galaxy, ejection should have occurred in opposite directions, whereby one object will be approaching us and the other will be receding from us. The former would be exhibiting a blueshifted spectrum. We analyse here a sample of four such pairs and show that the observed spectrum of one QSO in each pair can be interpreted as blueshifted. The other exhibits the ususal redshifted spectrum.A scenario based on the 'sling-shot' mechanism of ejection is presented to explain the ocurrences of the pairs in opposite sides of the active galaxies moving in opposite durections.

D. Basu

2007-01-08T23:59:59.000Z

185

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

SciTech Connect (OSTI)

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

186

Using Disorder to Study How Electrons Pair in Iron-Based Superconducto...  

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

Using Disorder to Study How Electrons Pair in Iron-Based Superconductors Researchers introduced disorder to test electron pairing in iron-based superconductors and produced...

187

Aerodynamic Effects in Weakly Ionized Gas: Phenomenology and Applications  

SciTech Connect (OSTI)

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

188

Generalized eikonal approximation for strong-field ionization  

E-Print Network [OSTI]

We develop the eikonal perturbation theory to describe the strong-field ionization by finite laser pulses. This approach in the first order with respect to the binding potential (the so-called generalized eikonal approximation) avoids a singularity at the potential center. Thus, in contrast to the ordinary eikonal approximation, it allows to treat rescattering phenomena in terms of quantum trajectories. We demonstrate how the first Born approximation and its domain of validity follow from eikonal perturbation theory. Using this approach, we study the coherent diffraction patterns in photoelectron energy spectra and their modifications induced by the interaction of photoelectrons with the atomic potential. Along with these first results, we discuss the prospects of using the generalized eikonal approximation to study strong-field ionization from multi-centered atomic systems and to study other strong-field phenomena.

Vélez, F Cajiao; Kami?ski, J Z

2015-01-01T23:59:59.000Z

189

Pulsed extraction of ionization from helium buffer gas  

E-Print Network [OSTI]

The migration of intense ionization created in helium buffer gas under the influence of applied electric fields is considered. First the chemical evolution of the ionization created by fast heavy-ion beams is described. Straight forward estimates of the lifetimes for charge exchange indicate a clear suppression of charge exchange during ion migration in low pressure helium. Then self-consistent calculations of the migration of the ions in the electric field of a gas-filled cell at the National Superconducting Cyclotron Laboratory (NSCL) using a Particle-In-Cell computer code are presented. The results of the calculations are compared to measurements of the extracted ion current caused by beam pulses injected into the NSCL gas cell.

D. J. Morrissey; G. Bollen; M. Facina; S. Schwarz

2008-08-13T23:59:59.000Z

190

Ionization front-driven turbulence in the clumpy interstellar medium  

E-Print Network [OSTI]

We present 3D radiation-gasdynamical simulations of an ionization front running into a dense clump. In our setup, a B0 star irradiates an overdensity which is at a distance of 10 pc and modelled as a supercritical 100 M_sol Bonnor-Ebert sphere. The radiation from the star heats up the gas and creates a shock front that expands into the interstellar medium. The shock compresses the clump material while the ionizing radiation heats it up. The outcome of this "cloud-crushing" process is a fully turbulent gas in the wake of the clump. In the end, the clump entirely dissolves. We propose that this mechanism is very efficient in creating short-living supersonic turbulence in the vicinity of massive stars.

Thomas Peters; Robi Banerjee; Ralf S. Klessen

2008-08-20T23:59:59.000Z

191

COSMIC RAY HEATING OF THE WARM IONIZED MEDIUM  

SciTech Connect (OSTI)

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

192

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

193

Development of laser excited atomic fluorescence and ionization methods  

SciTech Connect (OSTI)

Progress report: May 1, 1988 to December 31, 1991. The research supported by DE-FG05-88ER13881 during the past (nearly) 3 years can be divided into the following four categories: (1) theoretical considerations of the ultimate detection powers of laser fluorescence and laser ionization methods; (2) experimental evaluation of laser excited atomic fluorescence; (3) fundamental studies of atomic and molecular parameters in flames and plasmas; (4) other studies.

Winefordner, J.D.

1991-01-01T23:59:59.000Z

194

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

195

The effect of microhydration on ionization energies of thymine  

SciTech Connect (OSTI)

A combined theoretical and experimental study of the effect of microhydration on ionization energies (IEs) of thymine is presented. The experimental IEs are derived from photoionization efficiency curves recorded using tunable synchrotron VUV radiation. The onsets of the PIE curves are 8.85+-0.05, 8.60+-0.05, 8.55+-0.05, and 8.40+-0.05 eV for thymine, thymine mono-, di-, and tri-hydrates, respectively. The computed (EOM-IP-CCSD/cc-pVTZ) AIEs are 8.90, 8.51, 8.52, and 8.35 eV for thymine and the lowest isomers of thymine mono-, di-, and tri-hydrates. Due to large structural relaxation, the Franck-Condon factors for the 0<-- 0 transitions are very small shifting the apparent PIE onsets to higher energies. Microsolvation strongly affects IEs of thymine -- addition of each water molecule reduces the first vertical IE by 0.10-0.15 eV. The adiabatic IE decreases even more (up to 0.4 eV). The magnitude of the effect varies for different ionized states and for different isomers. For the ionized states that are localized on thymine the dominant contribution to the IE reduction is the electrostatic interaction between the delocalized positive charge on thymine and the dipole moment of the water molecule.

Khistyev, Kirill; Bravaya, Ksenia B.; Kamarchik, Eugene; Kostko, Oleg; Ahmed, Musahid; Krylov, Anna I.

2011-01-03T23:59:59.000Z

196

The multiphoton ionization of uranium hexafluoride. Revision 1  

SciTech Connect (OSTI)

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

197

High-resolution ionization detector and array of such detectors  

DOE Patents [OSTI]

A high-resolution ionization detector and an array of such detectors are described which utilize a reference pattern of conductive or semiconductive material to form interaction, pervious and measurement regions in an ionization substrate of, for example, CdZnTe material. The ionization detector is a room temperature semiconductor radiation detector. Various geometries of such a detector and an array of such detectors produce room temperature operated gamma ray spectrometers with relatively high resolution. For example, a 1 cm.sup.3 detector is capable of measuring .sup.137 Cs 662 keV gamma rays with room temperature energy resolution approaching 2% at FWHM. Two major types of such detectors include a parallel strip semiconductor Frisch grid detector and the geometrically weighted trapezoid prism semiconductor Frisch grid detector. The geometrically weighted detector records room temperature (24.degree. C.) energy resolutions of 2.68% FWHM for .sup.137 Cs 662 keV gamma rays and 2.45% FWHM for .sup.60 Co 1.332 MeV gamma rays. The detectors perform well without any electronic pulse rejection, correction or compensation techniques. The devices operate at room temperature with simple commercially available NIM bin electronics and do not require special preamplifiers or cooling stages for good spectroscopic results.

McGregor, Douglas S. (Ypsilanti, MI); Rojeski, Ronald A. (Pleasanton, CA)

2001-01-16T23:59:59.000Z

198

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

199

Isovector pairing collective motion: Generator-coordinate-method approach  

SciTech Connect (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.

Kyotoku, M.; Chen, H.

1987-09-01T23:59:59.000Z

200

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

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201

Effect of pairing on transfer and fusion reactions  

E-Print Network [OSTI]

In the present contribution, the effect of pairing on nuclear transfer and fusion reactions close to the Coulomb barrier is discussed. A Time-Dependent Hartree-Fock + BCS (TDHF+BCS) microscopic theory has been developed to incorporate pairing. One- and two-particle transfer probabilities can be obtained showing the importance of pairing. The calculated transfer probabilities are compared to the recent experimental results obtained for the $^{96}$Zr+$^{40}$Ca. Reactions involving the $^{18}$O with lead isotopes are also presented, that are also of current experimental interest. Finally, a study of the fusion barrier height predicted with the TDHF+BCS theory is compared to the experimental values for the $^{40,44,48}$Ca+$^{40}$Ca reactions.

Guillaume Scamps; Denis Lacroix

2014-02-19T23:59:59.000Z

202

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

203

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

204

Pairing Gaps, Pseudogaps, and Phase Diagrams for Cuprate Superconductors  

E-Print Network [OSTI]

We use a symmetry-constrained variational procedure to construct a generalization of BCS to include Cooper pairs with non-zero momentum and angular momentum. The resulting gap equations are solved at zero and finite temperature, and the doping-dependent solutions are used to construct gap and phase diagrams. We find a pseudogap terminating at a critical doping that may be interpreted in terms of both competing order and preformed pairs. The strong similarity between observation and predicted gap and phase structure suggests that this approach may provide a unified description of the complex structure observed for cuprate superconductors.

Yang Sun; Mike Guidry; Cheng-Li Wu

2007-02-21T23:59:59.000Z

205

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

206

Magnetic moments of T=3/2 mirror pairs  

SciTech Connect (OSTI)

We predict values of the magnetic moments of T=3/2 proton-rich fp-shell nuclei in the mass range A=43-53, by using known values for their neutron-rich mirrors together with shell-model estimates for small quantities. We extend the analysis to those T=3/2 sd-shell mirror pairs for which both the T{sub z}=-3/2 and T{sub z}=+3/2 magnetic moments have been measured. We find that these obey the same linear relation as previously deduced for T=1/2 mirror pairs.

Perez, S. M. [Department of Physics, University of Cape Town, Private Bag, Rondebosch 7700 (South Africa); iThemba LABS, P. O. Box 722, Somerset West 7129 (South Africa); Richter, W. A. [Department of Physics, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Brown, B. A. [Department of Physics and Astronomy, and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824-1321 (United States); Horoi, M. [Department of Physics, Central Michigan University, Mount Pleasant, Michigan 48859 (United States)

2010-12-15T23:59:59.000Z

207

Landau-Zener Transitions in Frozen Pairs of Rydberg Atoms  

SciTech Connect (OSTI)

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

208

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

SciTech Connect (OSTI)

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

209

Improved Approximations for Fermion Pair Production in Inhomogeneous Electric Fields  

E-Print Network [OSTI]

Reformulating the instantons in a complex plane for tunneling or transmitting states, we calculate the pair-production rate of charged fermions in a spatially localized electric field, illustrated by the Sauter electric field E_0 sech^2 (z/L), and in a temporally localized electric field such as E_0 sech^2 (t/T). The integration of the quadratic part of WKB instanton actions over the frequency and transverse momentum leads to the pair-production rate obtained by the worldline instanton method, including the prefactor, of Phys. Rev. D72, 105004 (2005) and D73, 065028 (2006). It is further shown that the WKB instanton action plus the next-to-leading order contribution in spinor QED equals the WKB instanton action in scalar QED, thus justifying why the WKB instanton in scalar QED can work for the pair production of fermions. Finally we obtain the pair-production rate in a spatially localized electric field together with a constant magnetic field in the same direction.

Sang Pyo Kim; Don N. Page

2007-01-31T23:59:59.000Z

210

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

211

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

212

Pair Production of Tau Sneutrinos at Linear Colliders  

E-Print Network [OSTI]

The pair production of tau sneutrinos in $e^{+}e^{-}$ collisions and their subsequent decays are studied in a framework of the supersymmetric extension of the standard model. We present an analysis for the parameter space (BR vs. mass) which could be explored at the future high energy $e^{+}e^{-}$ colliders.

V. Ari; O. Cakir

2010-07-15T23:59:59.000Z

213

List of things to bring: Notes Socks (5 pairs)  

E-Print Network [OSTI]

) Light weight fast drying pants are preferable. Shorts (one pair) Swim suit t-shirts (3-4) long-sleeved shirts (1-2) warm sweater or lightweight coat We may experience nightitme temperatures of down toclose or two Pencils are for your field books (prefered to ink which runs in humid weather). Important #12

Lougheed, Stephen

214

Blind subpixel Point Spread Function estimation from scaled image pairs  

E-Print Network [OSTI]

Blind subpixel Point Spread Function estimation from scaled image pairs Mauricio Delbracio§ Andr, causing aliasing effects. This work introduces a blind algorithm for the subpixel estimation of the point shows that the proposed algorithm reaches the accuracy levels of the best non- blind state

Paris-Sud XI, Université de

215

Radiative proton-antiproton annihilation to a lepton pair  

SciTech Connect (OSTI)

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

216

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

SciTech Connect (OSTI)

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

217

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

218

The ionizing radiation environment in space and its effects  

SciTech Connect (OSTI)

The ionizing radiation environment in space poses a hazard for spacecraft and space crews. The hazardous components of this environment are reviewed and those which contribute to radiation hazards and effects identified. Avoiding the adverse effects of space radiation requires design, planning, monitoring and management. Radiation effects on spacecraft are avoided largely though spacecraft design. Managing radiation exposures of space crews involves not only protective spacecraft design and careful mission planning. Exposures must be managed in real time. The now-casting and forecasting needed to effectively manage crew exposures is presented. The techniques used and the space environment modeling needed to implement these techniques are discussed.

Adams, Jim; Falconer, David; Fry, Dan [Center for Space Plasma and Aeronomic Research (CSPAR), UA Huntsville (United States); Space Radiation Analysis Group, NASA Johnson Space Center (United States)

2012-11-20T23:59:59.000Z

219

Photo-ionization and residual electron effects in guided streamers  

SciTech Connect (OSTI)

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

220

Fluid description of multi-component solar partially ionized plasma  

SciTech Connect (OSTI)

We derive self-consistent formalism for the description of multi-component partially ionized solar plasma, by means of the coupled equations for the charged and neutral components for an arbitrary number of chemical species, and the radiation field. All approximations and assumptions are carefully considered. Generalized Ohm's law is derived for the single-fluid and two-fluid formalism. Our approach is analytical with some order-of-magnitude support calculations. After general equations are developed, we particularize to some frequently considered cases as for the interaction of matter and radiation.

Khomenko, E., E-mail: khomenko@iac.es; Collados, M.; Vitas, N. [Instituto de Astrofísica de Canarias, 38205 La Laguna, Tenerife (Spain); Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife (Spain); Díaz, A. [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain)

2014-09-15T23:59:59.000Z

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.


221

Runaway electrons in a fully and partially ionized nonideal plasma  

SciTech Connect (OSTI)

This paper reports on a study of electron runaway for a nonideal plasma in an external electric field. Based on pseudopotential models of nonideal fully and partially ionized plasmas, the friction force was derived as a function of electron velocities. Dependences of the electron free path on plasma density and nonideality parameters were obtained. The impact of the relative number of runaway electrons on their velocity and temperature was considered for classical and semiclassical models of a nonideal plasma. It has been shown that for the defined intervals of the coupled plasma parameter, the difference between the relative numbers of runaway electron values is essential for various plasma models.

Ramazanov, T.S.; Turekhanova, K.M. [Al Farabi Kazakh National University, IETP, Tole bi 96a, Almaty 050012 (Kazakhstan)

2005-10-01T23:59:59.000Z

222

Unambiguous ionization amplitudes for electron-hydrogen scattering  

SciTech Connect (OSTI)

According to quantum collision theory, scattering amplitudes are complex numbers, which are completely defined by their magnitude and phase. Although the phase information is generally not determined entirely in collision experiments, the phases are well defined and can be used to check computational models. We use four state-of-the-art approaches to calculate the magnitude and phase of the electron-hydrogen ionization amplitude in the Temkin-Poet S-wave model. We demonstrate that the correct phase can be extracted for each method by using the appropriate final-state continuum functions.

Bartlett, P. L.; Bray, I.; Jones, S.; Stelbovics, A. T.; Kadyrov, A. S.; Bartschat, K.; Ver Steeg, G. L.; Scott, M. P.; Burke, P. G. [Centre for Atomic, Molecular, and Surface Physics, School of Mathematical and Physical Sciences, Murdoch University, Perth 6150, (Australia); Department of Applied Mathematics and Theoretical Physics, The Queen's University of Belfast, Belfast BT7 1NN, Northern Ireland (Ireland)

2003-08-01T23:59:59.000Z

223

Metabolic Differences in Microbial Cell Populations Revealed by Nanophotonic Ionization  

SciTech Connect (OSTI)

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

224

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

225

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

226

Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systemsBi (2)Sharing SmartversatileplatformSite-Selective Ionization in

227

Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systemsBi (2)Sharing SmartversatileplatformSite-Selective Ionization

228

Ionization wave propagation on a micro cavity plasma array  

SciTech Connect (OSTI)

Microcavity plasma arrays of inverse pyramidal cavities fabricated on p-Si wafers act as localized dielectric barrier discharges. When operated at atmospheric pressure in argon and excited with high voltage at 10 kHz, a strong interaction between individual cavities is observed leading to wave-like optical emission propagating along the surface of the array. This phenomenon is numerically investigated. The computed ionization wave propagates with a speed of 5 km/s, which agrees well with experiments. The wave propagation is due to the sequential drift of electrons followed by drift of ions between cavities seeded by photoemission of electrons by the plasma in adjacent cavities.

Wollny, Alexander; Hemke, Torben; Gebhardt, Markus; Peter Brinkmann, Ralf; Mussenbrock, Thomas [Institute of Theoretical Electrical Engineering, Ruhr University Bochum, D-44780 Bochum (Germany); Boettner, Henrik; Winter, Joerg; Schulz-von der Gathen, Volker [Institute for Experimental Physics II, Ruhr University Bochum, D-44780 Bochum (Germany); Xiong, Zhongmin; Kushner, Mark J. [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109 (United States)

2011-10-03T23:59:59.000Z

229

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

230

A link between solar events and congenital malformations: Is ionizing radiation enough to explain it?  

E-Print Network [OSTI]

Cosmic rays are known to cause biological effects directly and through ionizing radiation produced by their secondaries. These effects have been detected in airline crews and other specific cases where members of the population are exposed to above average secondary fluxes. Recent work has found a correlation between solar particle events and congenital malformations. In this work we use the results of computational simulations to approximate the ionizing radiation from such events as well as longer term increases in cosmic ray flux. We find that the amounts of ionizing radiation produced by these events are insufficient to produce congenital malformations under the current paradigm regarding muon ionizing radiation. We believe that further work is needed to determine the correct ionizing radiation contribution of cosmogenic muons. We suggest that more extensive measurements of muon radiation effects may show a larger contribution to ionizing radiation dose than currently assumed.

Overholt, A C; Atri, D

2015-01-01T23:59:59.000Z

231

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

SciTech Connect (OSTI)

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

232

Calculation of electron-impact ionization using the J-matrix method  

SciTech Connect (OSTI)

The J-matrix approach to electron-atom scattering is applied to ionization processes. We consider the Temkin-Poet model of e-H ionization. Convergence issues are studied with greater detail than previously possible using other close-coupling methods. The numerical strengths of the technique are emphasized with the long-term goal of application to ionization-plus-excitation processes.

Konovalov, D. A.; Bray, I. [Discipline of Information Technology, School of Business, James Cook University, Townsville, Queensland 4811 (Australia); ARC Centre for Antimatter-Matter Studies, Curtin University of Technology, GPO Box U1987, Perth, Western Australia 6845 (Australia)

2010-08-15T23:59:59.000Z

233

Detection of methoxylated anions of fullerenes by electrospray ionization mass spectrometry  

SciTech Connect (OSTI)

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

234

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

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

235

Threshold law for ionization cross sections in the Temkin-Poet model  

SciTech Connect (OSTI)

An integral representation of wave functions for the Temkin-Poet model of electron impact on atomic hydrogen is given. Approximate wave functions are evaluated analytically for large hyperradius to extract the ionization S-matrix element. An ionization cross section of the form exp[{minus}aE{sup {minus}1/6}+bE{sup 1/6}], where a and b are positive constants, is derived. The exponential suppression of ionization for small E appears to be the quantum counterpart of the delayed onset of ionization in the classical theory for this model. {copyright} {ital 1997} {ital The American Physical Society}

Macek, J.H. [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996-1501 (United States)] [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996-1501 (United States); [Oak Ridge National Laboratory, Post Office Box 2009, Oak Ridge, Tennessee 37831 (United States); Ihra, W. [Department of Mathematics, Royal Holloway, University of London, Egham, Surry TW20 0EX (United Kingdom)] [Department of Mathematics, Royal Holloway, University of London, Egham, Surry TW20 0EX (United Kingdom)

1997-03-01T23:59:59.000Z

236

E-Print Network 3.0 - applying ionizing radiation Sample Search...  

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

The two distinct regimes for coupling of the intense radiation... - second and nanosecond radiation excitation of large molecules. Both groups found enhanced ionization... , this...

237

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

SciTech Connect (OSTI)

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

238

Does the schock wave in a highly ionized non-isothermal plasma really exist ?  

E-Print Network [OSTI]

Here we study the structure of a highly ionizing shock wave in a gas of high atmospheric pressure. We take into account the gas ionization when the gas temperature reaches few orders of an ionization potential. It is shown that after gasdynamic temperature-raising shock and formation of a highly-ionized nonisothermal plasma $T_e>>T_i$ only the solitary ion-sound wave (soliton) can propagate in this plasma. In such a wave the charge separation occurs: electrons and ions form the double electric layer with the electric field. The shock wave form, its amplitude and front width are obtained.

Rukhadze, A A; Samkharadze, T

2015-01-01T23:59:59.000Z

239

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

2011-06-21T23:59:59.000Z

240

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

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

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

242

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

243

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

244

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

245

Methane ionization chamber to search for spin-dependent dark matter interactions  

E-Print Network [OSTI]

A liquid-methane ionization chamber is proposed as a setup to search for spin-dependent interactions of dark-matter particles with hydrogen

B. M. Ovchinnikov; V. V. Parusov; V. A. Bednyakov

2005-08-04T23:59:59.000Z

246

E-Print Network 3.0 - annular gas ionization Sample Search Results  

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

Collection: Plasma Physics and Fusion 70 Discharge Oscillations in a Permanent Magnet Cylindrical Hall-Effect Thruster Summary: ' mode ionization instability is identified,...

247

E-Print Network 3.0 - a-150 plastic ionization Sample Search...  

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

or equal to that supplied... by the ionization source, which is an ultraviolet (UV) lamp. Photoionization occurs when an atom or molecule absorbs Source: Los Alamos National...

248

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

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

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

249

New developments in biochemical mass spectrometry: Electrospray ionization  

SciTech Connect (OSTI)

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

250

Extended and Revised Analysis of Singly Ionized Tin: Sn II  

E-Print Network [OSTI]

The electronic structure of singly ionized tin (SnII) is partly a one-electron and partly a three-electron system with ground configuration 5s25p. The excited configurations are of the type 5s2nl in the one-electron part, and 5s5p2, 5p3 and 5s5pnl (nl = 6s, 5d) in the three-electron system with quartet and doublet levels. The spectrum analyzed in this work was recorded on a 3 m normal incidence vacuum spectrograph of the Antigonish laboratory (Canada) in the wavelength region 300 - 2080 {\\AA} using a triggered spark source. The existing interpretation of the one-electron level system was confirmed in this paper, while the 2S1/2 level of the 5s5p2 configuration has been revised. The analysis has been extended to include new configurations 5p3, 5s5p5d and 5s5p6s with the aid of superposition-of-configurations Hartree-Fock calculations with relativistic corrections. The ionization potential obtained from the ng series was found to be 118023.7(5) 1/cm (14.63307(6) eV). We give a complete set of critically evaluat...

Haris, K; Tauheed, A

2013-01-01T23:59:59.000Z

251

Collision dynamics of proton with formaldehyde: Fragmentation and ionization  

SciTech Connect (OSTI)

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

252

Effect of primordial magnetic fields on the ionization history  

E-Print Network [OSTI]

Primordial magnetic fields (PMF) damp at scales smaller than the photon diffusion and free-streaming scale. This leads to heating of ordinary matter (electrons and baryons), which affects both the thermal and ionization history of our Universe. Here, we study the effect of heating due to ambipolar diffusion and decaying magnetic turbulence. We find that changes to the ionization history computed with recfast are significantly overestimated when compared with CosmoRec. The main physical reason for the difference is that the photoionization coefficient has to be evaluated using the radiation temperature rather than the matter temperature. A good agreement with CosmoRec is found after changing this aspect. Using Planck 2013 data and considering only the effect of PMF-induced heating, we find an upper limit on the r.m.s. magnetic field amplitude of B0 < 1.1 nG (95% c.l.) for a stochastic background of PMF with a nearly scale-invariant power spectrum. We also discuss uncertainties related to the approximations ...

Chluba, Jens; Finelli, Fabio; Rubino-Martin, Jose-Alberto

2015-01-01T23:59:59.000Z

253

Analysis of 3-panel and 4-panel microscale ionization sources  

SciTech Connect (OSTI)

Two designs of a microscale electron ionization (EI) source are analyzed herein: a 3-panel design and a 4-panel design. Devices were fabricated using microelectromechanical systems technology. Field emission from carbon nanotube provided the electrons for the EI source. Ion currents were measured for helium, nitrogen, and xenon at pressures ranging from 10{sup -4} to 0.1 Torr. A comparison of the performance of both designs is presented. The 4-panel microion source showed a 10x improvement in performance compared to the 3-panel device. An analysis of the various factors affecting the performance of the microion sources is also presented. SIMION, an electron and ion optics software, was coupled with experimental measurements to analyze the ion current results. The electron current contributing to ionization and the ion collection efficiency are believed to be the primary factors responsible for the higher efficiency of the 4-panel microion source. Other improvements in device design that could lead to higher ion source efficiency in the future are also discussed. These microscale ion sources are expected to find application as stand alone ion sources as well as in miniature mass spectrometers.

Natarajan, Srividya; Parker, Charles B.; Glass, Jeffrey T. [Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States); Piascik, Jeffrey R.; Gilchrist, Kristin H. [Center for Materials and Electronic Technologies, RTI International, Research Triangle Park, North Carolina 27709 (United States); Stoner, Brian R. [Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States); Center for Materials and Electronic Technologies, RTI International, Research Triangle Park, North Carolina 27709 (United States)

2010-06-15T23:59:59.000Z

254

Eigenstate Localization in an Asymmetric Coupled Quantum Well Pair  

SciTech Connect (OSTI)

Optical pumping of a type-I/type-II coupled asymmetric quantum well pair induces a spatially separated two dimensional charge carriers plasma in the well's wide and narrow parts. Treating the two coupled wells as a single system we find that the eigenstate probability distribution localizes exclusively either in the wide or the narrow parts of the well pair. The energy of the narrow-well localized state determines the minimal excitation energy for optically pumped charge carriers separation. In a previously used design [Guliamov et al., PRB 64 035314 (2001)] this narrow well transition energy was measured to correspond to a wavelength of 646 nm. We propose modifications to the design suggested earlier with the purpose of pushing up the energy required for the optical pumping of the two-dimensional plasma into the green and blue regions of the visible spectrum.

Mialitsin, A.; Schmult, S.; Solov'yov, I. A.; Fluegel, B.; Mascarenhas, A.

2012-06-01T23:59:59.000Z

255

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

256

Interference of Cooper Pairs Emitted from Independent Superconductors  

E-Print Network [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; Kazuya Yuasa

2010-05-16T23:59:59.000Z

257

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

258

Top quark pair production cross section at the Tevatron  

SciTech Connect (OSTI)

Top quark pair production cross section has been measured at the Tevatron by CDF and D0 collaborations using different channels and methods, in order to test standard model predictions, and to search for new physics hints affecting the t{bar t} production mechanism or decay. Measurements are carried out with an integrated luminosity of 1.0 to 2.0 fb{sup -1}, and are found to be consistent with standard model expectations.

Cortiana, Giorgio; /INFN, Padua /Padua U.

2008-04-01T23:59:59.000Z

259

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

260

Pair and Impar, Even and Odd Form Fields and Electromagnetism  

E-Print Network [OSTI]

In this paper after reviewing the Schouten and de Rham definition of impair and pair differential form fields (not to be confused with differential form fields of even and odd grades) we prove that in a relativistic spacetime it is possible (despite claims in contrary) to coherently formulate electromagnetism (and we believe any other physical theory) using only pair form fields or, if one wishes, using pair and impair form fields together, in an appropriate way. Those two distinct descriptions involve only a mathematical choice and do not seem to lead to any observable physical consequence if due care is taken. Moreover, we show in details that a formulation of electromagnetic theory in the Clifford bundle formalism of differential forms where the two Maxwell equations of the so called free metric approach becomes a single equation is compatible with both formulations of electromagnetism just mentioned above. Moreover we derive directly from Maxwell equation the density of force (coupling of the electromagnetic field with the charge current) that is a postulate in the free metric approach to electromagnetism. We recall also a formulation of the engineering version of Maxwell equations using electric and magnetic fields as objects of the same nature, i.e., without using polar and axial vectors.

Roldao da Rocha; Waldyr A. Rodrigues Jr

2009-08-13T23:59:59.000Z

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

Dust in the Ionized Medium of the Galaxy: GHRS Measurements of Al III and S III  

E-Print Network [OSTI]

We present interstellar absorption line measurements of the ions S III and Al III towards six stars using archival Goddard High Resolution Spectrograph data. The ions Al III and S III trace heavily depleted and non-depleted elements, respectively, in ionized gas. We use the photoionization code CLOUDY to derive the ionization correction relating N(Al III)/N(S III) to the gas-phase abundance [Al/S]_i in the ionized gas. For spectral types considered here, the corrections are small and independent of the assumed ionization parameter. Using the results of these photoionization models, we find [Al/S]_i = -1.0 in the ionized gas towards three disk stars. These values of [Al/S]_i (=[Al/H]_i) imply that Al-bearing grains are present in the ionized nebulae around these stars. If the WIM of the Galaxy is photoionized by OB stars, our data for two halo stars imply [Al/S]_i = -0.4 to -0.5 in the WIM and thus the presence of dust grains containing Al in this important phase of the ISM. While photoionization appears to be the most likely origin of the ionization for Al III and S III, we cannot rule out confusion from the presence of hot, collisionally ionized gas along two sightlines. We find that [Al/S]_i in the ionized gas along the six sightlines is anti-correlated with the electron density and average sightline neutral density. The degree of grain destruction in the ionized medium of the Galaxy is not much higher than in the warm neutral medium. The existence of grains in the ionized regions studied here has important implications for the thermal balance of these regions. (Abstract Abridged)

J. Christopher Howk; Blair D. Savage

1998-10-27T23:59:59.000Z

262

Exact results for ionization of model atomic systems  

SciTech Connect (OSTI)

We review recent rigorous results concerning the ionization of model quantum systems by time-periodic external fields. The systems we consider consist of a single particle (electron) with a reference Hamiltonian H{sub 0}=-{delta}+V{sub 0}(x) (x is an element of R{sup d}) having both bound and continuum states. Starting from an initially localized state {psi}{sub 0}(x) is an element of L{sup 2}(R{sup d}), the system is subjected for t{>=}0 to an arbitrary strength time-periodic potential V{sub 1}(x,t)=V{sub 1}(x,t+2{pi}/{omega}). We prove that for a large class of V{sub 0}(x) and V{sub 1}(x,t), the wave function {psi}(x,t) will delocalize as t{yields}{infinity}, i.e., the system will ionize. The only exceptions are cases where there are time-periodic bound states of the Floquet operator associated with H{sub 0}+V{sub 1}. These do occur (albeit rarely) when V{sub 1} is not small. For spatially rapidly decaying V{sub 0} and V{sub 1}, {psi}(x,t) is generally given, for very long times, by a power series in t{sup -1/2} which we prove in some cases to be Borel summable. For the Coulomb potential V{sub 0}(x)=-b|x|{sup -1} in R{sup 3}, we prove ionization for V{sub 1}(x,t)=V{sub 1}(|x|)sin({omega}t-{theta}), V{sub 1}(|x|)=0 for |x|>R and V{sub 1}(x)>0 for |x|{<=}R. For this model, if {psi}{sub 0} is compactly supported both in x and in angular momentum, L, we obtain that {psi}(x,t){approx}O(t{sup -5/6}) as t{yields}{infinity}.

Costin, O.; Tanveer, S. [Department of Mathematics, Ohio State University, Columbus, Ohio 43210 (United States); Lebowitz, J. L. [Department of Mathematics, Rutgers University, Piscataway, New Jersey 08854 (United States); Department of Physics, Rutgers University, Piscataway, New Jersey 08854 (United States); Stucchio, C. [Courant Institute, New York University, New York, New York 10276 (United States)

2010-01-15T23:59:59.000Z

263

STORAGE RING CROSS-SECTION MEASUREMENTS FOR ELECTRON IMPACT SINGLE AND DOUBLE IONIZATION OF Fe{sup 9+} AND SINGLE IONIZATION OF Fe{sup 10+}  

SciTech Connect (OSTI)

We have measured electron impact ionization from the ground state of Fe{sup 9+} and Fe{sup 10+} over the relative electron-ion collision energy ranges 200-1900 eV and 250-1800 eV, respectively. The ions were confined in an ion storage ring long enough for essentially all metastable levels to radiatively relax to the ground state. For single ionization, we find a number of discrepancies between the existing theoretical cross sections and our results. The calculations appear to neglect some excitation-autoionization (EA) channels, particularly from n = 3 to n' excitations, which are important near threshold, and those from n = 2 {yields} 3 excitations, which contribute at about 650 eV. Conversely, at higher energies the calculations appear to overestimate the importance of EA channels due to excitation into levels where n {>=} 4. The resulting experimental rate coefficients agree with the most recent theory for Fe{sup 9+} to within 16% and for Fe{sup 10+} to within 19% at temperatures where these ions are predicted to form in collisional ionization equilibrium. We have also measured double ionization of Fe{sup 9+} forming Fe{sup 11+} in the energy range 450-3000 eV and found that although there is an appreciable cross section for direct double ionization, the dominant mechanism appears to be through direct ionization of an inner shell electron producing an excited state that subsequently stabilizes through autoionization.

Hahn, M.; Novotny, O.; Savin, D. W. [Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Becker, A.; Grieser, M.; Krantz, C.; Wolf, A. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Lestinsky, M.; Repnow, R. [GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstr. 1, D-64291 Darmstadt (Germany); Mueller, A.; Schippers, S.; Spruck, K. [Institut fuer Atom- und Molekuelphysik, Justus-Liebig-Universitaet Giessen, Leihgesterner Weg 217, D-35392 Giessen (Germany)

2012-11-20T23:59:59.000Z

264

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

265

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

266

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.... The photoelectron yield rate for xenon ............................................................... 37 Fig. 20. The Runge divergence calculated for the model xenon probability function using (6...

Hart, Nathan Andrew

2012-10-19T23:59:59.000Z

267

LSU School of Dentistry Laser Safety : Clinical SAFETY PROCEDURES FOR LASER (NON-IONIZING) RADIATION  

E-Print Network [OSTI]

system is one that is considered to be incapable of producing damaging radiation levels during operation-IONIZING) RADIATION 1. PURPOSE This procedure sets forth the Louisiana State University (LSU) System non-ionizing radiation safety policy and procedural requirements of the program. The use of the term non

268

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

269

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

270

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

271

Charge Transfer Between Neutral Atoms and Highly Ionized Species: Implications for ISO Observations  

E-Print Network [OSTI]

We estimate rate coefficients for charge transfer between neutral hydrogen and helium and moderate to highly ionized heavy elements. Although charge transfer does not have much influence on hot collisionally ionized plasmas, its effects on photoionized plasmas can be profound. We present several photoionization models which illustrate the significant effect of charge transfer on the far infrared lines detected by ISO.

G. J. Ferland; K. T. Korista; D. A. Verner; A. Dalgarno

1997-03-17T23:59:59.000Z

272

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

273

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.

274

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

275

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

276

Explorations of Functionalized Gold Nanoparticle Surface Chemistry for Laser Desorption Ionization Mass Spectrometry Applications  

E-Print Network [OSTI]

EXPLORATIONS OF FUNCTIONALIZED GOLD NANOPARTICLE SURFACE CHEMISTRY FOR LASER DESORPTION IONIZATION MASS SPECTROMETRY APPLICATIONS A Thesis by MARIO ESTUARDO GOMEZ HERNANDEZ Submitted to the Office... DESORPTION IONIZATION MASS SPECTROMETRY APPLICATIONS A Thesis by MARIO ESTUARDO GOMEZ HERNANDEZ Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree...

Gomez Hernandez, Mario 1980-

2012-07-11T23:59:59.000Z

277

Ionization detector, electrode configuration and single polarity charge detection method  

DOE Patents [OSTI]

An ionization detector, an electrode configuration and a single polarity charge detection method each utilize a boundary electrode which symmetrically surrounds first and second central interlaced and symmetrical electrodes. All of the electrodes are held at a voltage potential of a first polarity type. The first central electrode is held at a higher potential than the second central or boundary electrodes. By forming the first and second central electrodes in a substantially interlaced and symmetrical pattern and forming the boundary electrode symmetrically about the first and second central electrodes, signals generated by charge carriers are substantially of equal strength with respect to both of the central electrodes. The only significant difference in measured signal strength occurs when the charge carriers move to within close proximity of the first central electrode and are received at the first central electrode. The measured signals are then subtracted and compared to quantitatively measure the magnitude of the charge.

He, Zhong (Ann Arbor, MI)

1998-01-01T23:59:59.000Z

278

Ionization detector, electrode configuration and single polarity charge detection method  

DOE Patents [OSTI]

An ionization detector, an electrode configuration and a single polarity charge detection method each utilize a boundary electrode which symmetrically surrounds first and second central interlaced and symmetrical electrodes. All of the electrodes are held at a voltage potential of a first polarity type. The first central electrode is held at a higher potential than the second central or boundary electrodes. By forming the first and second central electrodes in a substantially interlaced and symmetrical pattern and forming the boundary electrode symmetrically about the first and second central electrodes, signals generated by charge carriers are substantially of equal strength with respect to both of the central electrodes. The only significant difference in measured signal strength occurs when the charge carriers move to within close proximity of the first central electrode and are received at the first central electrode. The measured signals are then subtracted and compared to quantitatively measure the magnitude of the charge. 10 figs.

He, Z.

1998-07-07T23:59:59.000Z

279

Effects of ionizing radiation on modern ion exchange materials  

SciTech Connect (OSTI)

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

280

Theory of multiphoton and tunnel ionization in a bichromatic field  

SciTech Connect (OSTI)

The imaginary-time method [6, 7] is used to calculate the multiphoton and tunnel ionization probabilities for atoms in a laser radiation field part of which is converted into the second harmonic. We assume that the first harmonic has a linear or elliptical polarization and the second harmonic is polarized linearly, with its polarization vector making an arbitrary angle with that of the first harmonic. The mean momentum of the photoelectrons knocked out from atoms is shown to depend on the phase shift between the first and second harmonics and their mutual polarization and to be identically equal to zero for a monochromatic field. An important difference between the case of elliptical polarization and the case of linear polarization of both harmonics is the absence of conditions under which the conditions for dominance of one of the two generation mechanisms considered here can be identified during the generation of terahertz radiation from the region of optical breakdown in a gas.

Bagulov, D. S., E-mail: bagulov-denis@yandex.ru [Novosibirsk State University (Russian Federation); Kotelnikov, I. A., E-mail: I.A.Kotelnikov@inp.nsk.ru [Russian Academy of Sciences, Siberian Branch, Budger Institute of Nuclear Physics (Russian Federation)

2013-01-15T23:59:59.000Z

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.


281

Heating of the magnetized solar chromosphere by partial ionization effects  

E-Print Network [OSTI]

In this paper, we study the heating of the magnetized solar chromosphere induced by the large fraction of neutral atoms present in this layer. The presence of neutrals, together with the decrease with height of the collisional coupling, leads to deviations from the classical MHD behavior of the chromospheric plasma. A relative net motion appears between the neutral and ionized components, usually referred to as ambipolar diffusion. The dissipation of currents in the chromosphere is enhanced orders of magnitude due to the action of ambipolar diffusion, as compared to the standard ohmic diffusion. We propose that a significant amount of magnetic energy can be released to the chromosphere just by existing force-free 10--40 G magnetic fields there. As a consequence, we conclude that ambipolar diffusion is an important process that should be included in chromospheric heating models, as it has the potential to rapidly heat the chromosphere. We perform analytical estimations and numerical simulations to prove this i...

Khomenko, Elena

2011-01-01T23:59:59.000Z

282

Weakly Ionized Plasmas in Hypersonics: Fundamental Kinetics and Flight Applications  

SciTech Connect (OSTI)

The paper reviews some of the recent studies of applications of weakly ionized plasmas to supersonic/hypersonic flight. Plasmas can be used simply as means of delivering energy (heating) to the flow, and also for electromagnetic flow control and magnetohydrodynamic (MHD) power generation. Plasma and MHD control can be especially effective in transient off-design flight regimes. In cold air flow, nonequilibrium plasmas must be created, and the ionization power budget determines design, performance envelope, and the very practicality of plasma/MHD devices. The minimum power budget is provided by electron beams and repetitive high-voltage nanosecond pulses, and the paper describes theoretical and computational modeling of plasmas created by the beams and repetitive pulses. The models include coupled equations for non-local and unsteady electron energy distribution function (modeled in forward-back approximation), plasma kinetics, and electric field. Recent experimental studies at Princeton University have successfully demonstrated stable diffuse plasmas sustained by repetitive nanosecond pulses in supersonic air flow, and for the first time have demonstrated the existence of MHD effects in such plasmas. Cold-air hypersonic MHD devices are shown to permit optimization of scramjet inlets at Mach numbers higher than the design value, while operating in self-powered regime. Plasma energy addition upstream of the inlet throat can increase the thrust by capturing more air (Virtual Cowl), or it can reduce the flow Mach number and thus eliminate the need for an isolator duct. In the latter two cases, the power that needs to be supplied to the plasma would be generated by an MHD generator downstream of the combustor, thus forming the 'reverse energy bypass' scheme. MHD power generation on board reentry vehicles is also discussed.

Macheret, Sergey [Department of Mechanical and Aerospace Engineering, Princeton University, D-418 Engineering Quadrangle, Princeton, NJ 08544 (United States)

2005-05-16T23:59:59.000Z

283

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

284

E-Print Network 3.0 - analytic sib-pair linkage Sample Search...  

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

10:225-233 (1993) Improved Sib-Pair Linkage Test for Disease Susceptibility... statistic INTRODUCTION Sib-pair methods for detecting linkage are useful because they make no...

285

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

286

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

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

287

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

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

288

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

SciTech Connect (OSTI)

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

289

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

290

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

291

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

292

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

293

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

2007-11-17T23:59:59.000Z

294

Nonresonant ionization of oxygen molecules by femtosecond pulses: Plasma dynamics studied by time-resolved terahertz spectroscopy  

E-Print Network [OSTI]

contribution to laser plasmas generated in air,26 ionized oxygen O2 + plays an important role in the upperNonresonant ionization of oxygen molecules by femtosecond pulses: Plasma dynamics studied by time for exploring laser-induced ionization and plasma formation in gases. Plasma was produced in gaseous oxygen

Apkarian, V. Ara

295

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

296

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

297

FINDING THE FIRST COSMIC EXPLOSIONS. I. PAIR-INSTABILITY SUPERNOVAE  

SciTech Connect (OSTI)

The first stars are the key to the formation of primitive galaxies, early cosmological reionization and chemical enrichment, and the origin of supermassive black holes. Unfortunately, in spite of their extreme luminosities, individual Population III (Pop III) stars will likely remain beyond the reach of direct observation for decades to come. However, their properties could be revealed by their supernova explosions, which may soon be detected by a new generation of near-IR (NIR) observatories such as JWST and WFIRST. We present light curves and spectra for Pop III pair-instability supernovae calculated with the Los Alamos radiation hydrodynamics code RAGE. Our numerical simulations account for the interaction of the blast with realistic circumstellar envelopes, the opacity of the envelope, and Lyman absorption by the neutral intergalactic medium at high redshift, all of which are crucial to computing the NIR signatures of the first cosmic explosions. We find that JWST will detect pair-instability supernovae out to z ?> 30, WFIRST will detect them in all-sky surveys out to z ? 15-20, and LSST and Pan-STARRS will find them at z ?< 7-8. The discovery of these ancient explosions will probe the first stellar populations and reveal the existence of primitive galaxies that might not otherwise have been detected.

Whalen, Daniel J.; Smidt, Joseph; Lovekin, C. C. [T-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Even, Wesley; Fryer, Chris L. [CCS-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Frey, Lucille H. [HPC-3, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Johnson, Jarrett L.; Hungerford, Aimee L. [XTD-6, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Stiavelli, Massimo [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Holz, Daniel E. [Enrico Fermi Institute, Department of Physics, and Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Heger, Alexander [Monash Centre for Astrophysics, Monash University, Victoria 3800 (Australia); Woosley, S. E. [Department of Astronomy and Astrophysics, UCSC, Santa Cruz, CA 95064 (United States)

2013-11-10T23:59:59.000Z

298

Modeling the secular evolution of migrating planet pairs  

E-Print Network [OSTI]

The subject of this paper is the secular behaviour of a pair of planets evolving under dissipative forces. In particular, we investigate the case when dissipative forces affect the planetary semi-major axes and the planets move inward/outward the central star, in a process known as planet migration. To perform this investigation, we introduce fundamental concepts of conservative and dissipative dynamics of the three-body problem. Based on these concepts, we develop a qualitative model of the secular evolution of the migrating planetary pair. Our approach is based on analysis of the energy and the orbital angular momentum exchange between the two-planet system and an external medium; thus no specific kind of dissipative forces is invoked. We show that, under assumption that dissipation is weak and slow, the evolutionary routes of the migrating planets are traced by the Mode I and Mode II stationary solutions of the conservative secular problem. The ultimate convergence and the evolution of the system along one...

Michtchenko, Tatiana A

2011-01-01T23:59:59.000Z

299

Creation of Electron Spinless Pairs in the Superconductivity  

E-Print Network [OSTI]

First, it is demonstrated that the Froolich Hamiltonian of system in the superconductivity, proposed by the model of a phonon gas and an electron gas mixture, contains a subtle error. In this respect, we present a correct form of the Froolich Hamiltonian of system where the term of the interaction between the phonon modes and the density modes of the electron modes is described by the term of scattering, introduced by the Froolich in a phonon gas electron gas mixture. The later is removed by a canonical transformation of the Froolich Hamiltonian by an appearance of the attractive interaction mediated via the electron modes, which leads to a bound state on a spinless electron pairs. In this letter, we show that the Cooper approximation as the constancy of the density states within around of the Fermi level has a flaw because the effective attractive forces cannot create the Cooper pairs into energetic gap at the Fermi level. In this letter, we find a condition for density metal which determines metal as superconductor.

V. N. Minasyan

2009-03-28T23:59:59.000Z

300

Search for pair production of second generation scalar leptoquarks  

SciTech Connect (OSTI)

We report on a search for the pair production of second generation scalar leptoquarks (LQ) in p{bar p} collisions at the center of mass energy {radical}s = 1.96TeV using a data set corresponding to an integrated luminosity of 1.0 fb{sup -1} collected with the D0 experiment at the Fermilab Tevatron Collider. Topologies arising from the LQ{ovr LQ} {yields} {mu}q{nu}q and LQ{ovr LQ} {yields} {mu}q{mu}q decay modes are investigated. No excess of data over the standard model prediction is observed and upper limits on the leptoquark pair production cross section are derived at the 95% C.L. as a function of the leptoquark mass and the branching fraction {beta} for the decay LQ {yields} {mu}q. These are interpreted as lower limits on the leptoquark mass as a function of {beta}. For {beta} = 1 (0.5), scalar second generation leptoquarks with masses up to 316GeV (270GeV) are excluded.

Abazov, V.M.; /Dubna, JINR; Abbott, B.; /Oklahoma U.; Abolins, M.; /Michigan State U.; Acharya, B.S.; /Tata Inst.; Adams, M.; /Illinois U., Chicago; Adams, T.; /Florida State U.; Aguilo, E.; /Alberta U. /Simon Fraser U. /York U., Canada /McGill U.; Ahsan, M.; /Kansas State U.; Alexeev, G.D.; /Dubna, JINR; Alkhazov, Georgiy D.; /St. Petersburg, INP; Alton, Andrew K.; /Michigan U. /Northeastern U.

2008-08-01T23:59:59.000Z

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.


301

Nonzero angular momentum pairing correlation in shell model  

E-Print Network [OSTI]

A simple approximation to shell model is proposed in which the low energy excitation spectra corresponds to the identical nucleons occupying the same single particle states where they preferred to form pairs for the ground states. We call this approximation as nonzero angular momentum pairing shell model. It not only reduces the dimensionality of the shell model but also matches the number of low energy levels in experimental spectra for few cases where exact shell model predicts many more states. The special focus has been done to consider the realistic interaction derived from free nucleon-nucleon scattering data to cope with the experimental spectra. The proposed approximation to shell model has been applied to calculate the energy spectra of O18 and Ni58 nuclei where only two neutrons occupy the valence states outside the core. When compared with the experimental data, the results are found to be encouraging. It is expected that results will be more pronounced if the even-even nuclei with higher number of valence nucleons are considered.

S. Haq; Y. Sadeq; I. M. Hamammu

2008-10-07T23:59:59.000Z

302

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

SciTech Connect (OSTI)

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

303

Electrospray Ionization Mass Spectrometry of hexanitrohexaazaisowurtzitane (CL-20)  

SciTech Connect (OSTI)

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

304

Multiphoton ionization of H{sub 2}{sup +} in xuv laser pulses  

SciTech Connect (OSTI)

We consider the ionization of the hydrogen molecular ion after one-, two-, and three-photon absorption over a large range of photon energies between 9 and 40 eV in the fixed-nuclei approximation. The temporal development of the system is obtained in a fully ab initio time-dependent grid-based approach in prolate spheroidal coordinates. The alignment dependence of the one-photon ionization amplitude is highlighted in the framework of time-dependent perturbation theory. For one-photon ionization as a function of the nuclear separation, the calculations reveal a significant minimum in the ionization probability. The suppressed ionization is attributed to a Cooper-type minimum, which is similar, but not identical, to the cancellation effect observed in photoionization cross sections of some noble-gas atoms. The effect of the nonspherical two-center Coulomb potential is analyzed. For two- and three-photon ionization, the angle-integrated cross sections clearly map out intermediate-state resonances, and the predictions of the current computations agree very well with those from time-independent calculations. The dominant emission modes for two-photon ionization are found to be very similar in both resonance and off-resonance regions.

Guan Xiaoxu; Secor, Ethan B.; Bartschat, Klaus [Department of Physics and Astronomy, Drake University, Des Moines, Iowa 50311 (United States); Schneider, Barry I. [Office of Cyberinfrastructure, National Science Foundation, Arlington, Virgina 22230 (United States)

2011-09-15T23:59:59.000Z

305

Seems a Fate in It: Misdirection and Foreshadowing in Bleak House and A Pair of Blue Eyes  

E-Print Network [OSTI]

for Action in A Pair of Blue Eyes. ” English Literature in2013). Hardy, Thomas. A Pair of Blue Eyes. Harmondsworth,aware of Thomas Hardy. A Pair of Blue Eyes. (Harmondsworth,

Bradfield, Meredith

2013-01-01T23:59:59.000Z

306

The oncogenic action of ionizing radiation on rat skin  

SciTech Connect (OSTI)

The multistage theory of carcinogenesis specifies that cells progress to cancer through a series of discrete, irreversible genetic alterations, but data on radiation-induced cancer incidence in rat skin suggests that an intermediate repairable alteration may occur. Data are presented on cancer induction in rat skin exposed to an electron beam (LET=0.34 keV/[mu]), a neon ion beam (LET=45) or an argon ion beam (LET=125). The rats were observed for tumors at least 78 weeks with squamous and basal cell carcinomas observed. The total cancer yield was fitted by the quadratic equation, and the equation parameters were estimated by linear regression for each type of radiation. Analysis of the DNA from the electron-induced carcinomas indicated that K-ras and/or c-myc oncogenes were activated. In situ hybridization indicated that the cancers contain subpopulations of cells with differing amounts of c-myc and H-ras amplification. The results are consistent with the idea that ionizing radiation produces stable, carcinogenically relevant lesions via 2 repairable events at low LET and via a non-repairable linked event pathway at high LET; either pathway may advance the cell by 1 stage. The proliferative response of rat epidermis following exposure to ionizing radiation was quantified by injection of [sup 14]C-thymidine. The return of these cells to S-phase a second time was detected by a second label ([sup 3]H). When the labeled cells were in G1-phase, the dorsal skin was irradiated with X-rays. All labeling indices were determined. The [sup 14]C labeling index was constant and unaffected by the radiation. The proportion of all cells entering S-phase averaged 3.5% at 18 hr and increased after 44, 52 and 75 hr to average levels of 11.8%, 5. 3%, and 6.6% at 0, 10 and 25 Gy respectively. The proportion of S-phase cells labeled with [sup 14]C increased after 42 hr and remained relatively constant thereafter.

Burns, F.J.; Garte, S.J.

1992-01-01T23:59:59.000Z

307

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

308

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

SciTech Connect (OSTI)

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

309

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

SciTech Connect (OSTI)

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

310

Electrospray ionization mass spectrometric characterization of acrylamide adducts to hemoglobin  

SciTech Connect (OSTI)

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

311

ICOOL: A SIMULATION CODE FOR IONIZATION COOLING OF MUON BEAMS.  

SciTech Connect (OSTI)

Current ideas [1,2] for designing a high luminosity muon collider require significant cooling of the phase space of the muon beams. The only known method that can cool the beams in a time comparable to the muon lifetime is ionization cooling [3,4]. This method requires directing the particles in the beam at a large angle through a low Z absorber material in a strong focusing magnetic channel and then restoring the longitudinal momentum with an rf cavity. We have developed a new 3-D tracking code ICOOL for examining possible configurations for muon cooling. A cooling system is described in terms of a series of longitudinal regions with associated material and field properties. The tracking takes place in a coordinate system that follows a reference orbit through the system. The code takes into account decays and interactions of {approx}50-500 MeV/c muons in matter. Material geometry regions include cylinders and wedges. A number of analytic models are provided for describing the field configurations. Simple diagnostics are built into the code, including calculation of emittances and correlations, longitudinal traces, histograms and scatter plots. A number of auxiliary files can be generated for post-processing analysis by the user.

FERNOW,R.C.

1999-03-25T23:59:59.000Z

312

The Role of Partial Ionization Effects in the Chromosphere  

E-Print Network [OSTI]

The energy for the coronal heating must be provided from the convection zone. The amount and the method by which this energy is transferred into the corona depends on the properties of the lower atmosphere and the corona itself. We review: 1) how the energy could be built in the lower solar atmosphere; 2) how this energy is transferred through the solar atmosphere; and 3) how the energy is finally dissipated in the chromosphere and/or corona. Any mechanism of energy transport has to deal with the various physical processes in the lower atmosphere. We will focus on a physical process that seems to be highly important in the chromosphere and not deeply studied until recently: the ion-neutral interaction effects (INIE) in the chromosphere. We review the relevance and the role of the partial ionization in the chromosphere and show that this process actually impacts considerably the outer solar atmosphere. We include analysis of our 2.5D radiative MHD simulations with the Bifrost code (Gudiksen et al. 2011) includ...

Martinez-Sykora, Juan; Hansteen, Viggo H; Carlsson, Mats

2015-01-01T23:59:59.000Z

313

Detecting excess ionizing radiation by electromagnetic breakdown of air  

SciTech Connect (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 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

314

Energy flux of Alfven waves in weakly ionized plasma  

E-Print Network [OSTI]

The overshooting convective motions in the solar photosphere are frequently proposed as the source for the excitation of Alfv\\'en waves. However, the photosphere is a) very weakly ionized, and, b) the dynamics of the plasma particles in this region is heavily influenced by the plasma-neutral collisions. The purpose of this work is to check the consequences of these two facts on the above scenario and their effects on the electromagnetic waves. It is shown that the ions and electrons in the photosphere are both un-magnetized; their collision frequency with neutrals is much larger than the gyro-frequency. This implies that eventual Alfv\\'en-type electromagnetic perturbations must involve the neutrals as well. This has the following serious consequences: i) in the presence of perturbations, the whole fluid (plasma + neutrals) moves; ii) the Alfv\\'en velocity includes the total (plasma + neutrals) density and is thus considerably smaller compared to the collision-less case; iii) the perturbed velocity of a unit volume, which now includes both plasma and neutrals, becomes much smaller compared to the ideal (collision-less) case; and iv) the corresponding wave energy flux for the given parameters becomes much smaller compared to the ideal case.

J. Vranjes; S. Poedts; B. P. Pandey; B. De Pontieu

2008-05-29T23:59:59.000Z

315

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

316

Enhanced superconducting pairing interaction in indium-doped tin telluride  

SciTech Connect (OSTI)

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

317

Enhanced superconducting pairing interaction in indium-doped tin telluride  

SciTech Connect (OSTI)

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

318

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

319

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

320

The effects of diet and ionizing radiation on azoxymethane induced colon carcinogenesis  

E-Print Network [OSTI]

The ability of ionizing radiation to enhance colon carcinogenesis and the role of diet in this process has not been documented. We hypothesized that radiation would enhance the formation of aberrant crypt foci, ACF, known precursor lesions to colon...

Mann, John Clifford

2006-10-30T23:59:59.000Z

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

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

322

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

323

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

324

A postsource decay study of bradykinin by Matrix-assisted laser desorption ionization mass spectrometry  

E-Print Network [OSTI]

Matrix-assisted laser desorption/ionization (MALDI) with time-of-flight (TOF) mass spectrometry is a very powerful technique for the analysis of peptides and proteins. Fragmentation reactions of the protonated analyte molecule, [M+H]+ ions...

Wei, Xiaona

1996-01-01T23:59:59.000Z

325

Effective polarization interaction potential 'charge-atom' for partially ionized dense plasma  

SciTech Connect (OSTI)

The pseudopotentials of particle interaction, taking into account quantum-mechanical effects of diffraction at short distances and also screening effects at large distances, are obtained for a partially ionized plasma. The dielectric function method was used.

Ramazanov, T.S.; Dzhumagulova, K.N.; Omarbakiyeva, Y.A. [Al Farabi Kazakh National University, IETP, Tole bi 96a, Almaty 050012 (Kazakhstan)

2005-09-15T23:59:59.000Z

326

Threshold law for electron impact ionization in the model of Temkin and Poet  

SciTech Connect (OSTI)

The angle-Sturmian theory is used to derive the threshold law for ionization of atomic hydrogen by electron impact in the model of Temkin and Poet. In this model, the exact electron-electron interaction is replaced by its monopole term. As for Wannier`s theory with the real interaction, ionization occurs only for electrons that start out nearly equidistant from the proton. Because there is a high propensity for one electron to be captured into a bound state, ionization is strongly suppressed, giving rise to a threshold law of the form {sigma} {proportional_to} exp[{minus}aE{sup {minus}1/6} + bE{sup 1/6}], where a and b are constants. The exponential law appears to be the quantal counterpart of the classical offset of the ionization threshold. Relative energy distribution are computed and found to favor configurations with unequal energy sharing.

Macek, J.H. [Univ. of Tennessee, Knoxville, TN (United States)

1996-05-01T23:59:59.000Z

327

A study of the tropospheric oxidation of volatile organic compounds using chemical ionization mass spectrometry  

E-Print Network [OSTI]

The mechanisms and kinetics of reactions important to the troposphere have been investigated using a high pressure, turbulent, discharge-flow technique coupled to a chemical ionization mass spectrometer. The ability to ...

Broekhuizen, Keith Edward, 1974-

2002-01-01T23:59:59.000Z

328

The effect of solvent on matrix-assisted laser desorption ionization mass spectrometry  

E-Print Network [OSTI]

Since its introduction in 1988, matrix-assisted laser desorption/ionization mass spectrometry (MALDI) has developed into a useful analytical tool in the biological field. The work presented here focuses on the effect of solvent on MALDI ion yields...

Campo, Karen Kay

1996-01-01T23:59:59.000Z

329

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

330

Irradiators for measuring the biological effects of low dose-rate ionizing radiation fields  

E-Print Network [OSTI]

Biological response to ionizing radiation differs with radiation field. Particle type, energy spectrum, and dose-rate all affect biological response per unit dose. This thesis describes methods of spectral analysis, ...

Davidson, Matthew Allen

2011-01-01T23:59:59.000Z

331

Periodic orbit bifurcations as an ionization mechanism: The bichromatically driven hydrogen atom  

E-Print Network [OSTI]

We investigate the multiphoton ionization of hydrogen driven by a strong bichromatic microwave field. In a regime where classical and quantum simulations agree, periodic orbit analysis captures the mechanism: Through the linear stability of periodic orbits we match qualitatively the variation of experimental ionization rates with control parameters such as the amplitudes of the two modes of the field or their relative phases. Moreover, we discuss an empirical formula which reproduces quantum simulations to a high degree of accuracy. This quantitative agreement shows the mechanism by which short periodic orbits organize the dynamics in multiphoton ionization. We also analyze the effect of longer pulse durations. Finally we compare our results with those based on the peak amplitude rule. Both qualitative and quantitative analyses are implemented for different mode locked fields. In parameter space, the localization of the period doubling and halving allows one to predict the set of parameters (amplitudes and phase lag) where ionization occurs.

S. Huang; C. Chandre; T. Uzer

2007-12-17T23:59:59.000Z

332

Are Neutral Sunspot Winds Important for Penumbral Dynamics and the First Ionization Potential Effect?  

E-Print Network [OSTI]

The low ionization state in parts of a sunspot may play an important role in its evolution and dynamical state. The cool magnetic interior region of the sunspot develops a substantial neutral atomic and molecular hydrogen osmotic pressure which can drive a wind outward from the umbra. Ambipolar diffusion against the magnetically pinned ionized plasma component can also distort the umbral magnetic field into a filamentary penumbral structure. This may be important for explaining the development of the sunspot penumbra and the Evershed flow. This fractionation process may also be important for the ``First Ionization Potential'' (FIP) effect seen in the solar wind. In support of this mechanism we find evidence for such ionization fractionization in UV observations of molecular hydrogen in a sunspot umbra and penumbra.

J. R. Kuhn; H. Lin; H. Morgan

2005-09-29T23:59:59.000Z

333

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

SciTech Connect (OSTI)

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

334

Resonant- and avalanche-ionization amplification of laser-induced plasma in air  

SciTech Connect (OSTI)

Amplification of laser-induced plasma in air is demonstrated utilizing resonant laser ionization and avalanche ionization. Molecular oxygen in air is ionized by a low-energy laser pulse employing (2 + 1) resonance-enhanced multi-photon ionization (REMPI) to generate seed electrons. Subsequent avalanche ionization of molecular oxygen and nitrogen significantly amplifies the laser-induced plasma. In this plasma-amplification effect, three-body attachments to molecular oxygen dominate the electron-generation and -loss processes, while either nitrogen or argon acts as the third body with low electron affinity. Contour maps of the electron density within the plasma obtained in O{sub 2}/N{sub 2} and O{sub 2}/Ar gas mixtures are provided to show relative degrees of plasma amplification with respect to gas pressure and to verify that the seed electrons generated by O{sub 2} 2 + 1 REMPI are selectively amplified by avalanche ionization of molecular nitrogen in a relatively low-pressure condition (?100?Torr). Such plasma amplification occurring in air could be useful in aerospace applications at high altitude.

Wu, Yue; Zhang, Zhili, E-mail: zzhang24@utk.edu [Department of Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Jiang, Naibo; Roy, Sukesh [Spectral Energies, LLC, 5100 Springfield St., Suite 301, Dayton, Ohio 45431 (United States); Gord, James R. [Air Force Research Laboratory, Aerospace Systems Directorate, Wright-Patterson Air Force Base, Ohio 45433 (United States)

2014-10-14T23:59:59.000Z

335

Investigation of ionized metal flux in enhanced high power impulse magnetron sputtering discharges  

SciTech Connect (OSTI)

The metal ionized flux fraction and production of double charged metal ions Me{sup 2+} of different materials (Al, Cu, Fe, Ti) by High Power Impulse Magnetron Sputtering (HiPIMS) operated with and without a pre-ionization assistance is compared in the paper. The Electron Cyclotron Wave Resonance (ECWR) discharge was employed as the pre-ionization agent providing a seed of charge in the idle time of HiPIMS pulses. A modified grid-free biased quartz crystal microbalance was used to estimate the metal ionized flux fraction ?. The energy-resolved mass spectrometry served as a complementary method to distinguish particular ion contributions to the total ionized flux onto the substrate. The ratio between densities of doubly Me{sup 2+} and singly Me{sup +} charged metal ions was determined. It is shown that ECWR assistance enhances Me{sup 2+} production with respect of absorbed rf-power. The ECWR discharge also increases the metal ionized flux fraction of about 30% especially in the region of lower pressures. Further, the suppression of the gas rarefaction effect due to enhanced secondary electron emission of Me{sup 2+} was observed.

Stranak, Vitezslav, E-mail: stranak@prf.jcu.cz [Faculty of Science, University of South Bohemia, Branisovska 31, 37005 Ceske Budejovice (Czech Republic); Hubicka, Zdenek; Cada, Martin [Institute of Physics v. v. i., Academy of Science of the Czech Republic, Na Slovance 2, 182 21 Prague (Czech Republic); Drache, Steffen; Hippler, Rainer [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, Felix-Hausdorff-Str. 6, 17489 Greifswald (Germany); Tichy, Milan [Faculty of Mathematics and Physics, Charles University in Prague, V Holesovickach 2, 180 00 Prague (Czech Republic)

2014-04-21T23:59:59.000Z

336

Ionization rate coefficients and induction times in nitrogen at high values of E/N  

SciTech Connect (OSTI)

Electron-impact ionization rate coefficients in nitrogen at values of E/N, the ratio of the electric field to the neutral density, up to 12 000 Td (1 Td = 10/sup -17/ V cmS), are reported. In addition, we report experimental measurements of the ionization induction time, the time during the early portion of an applied electric field when the electron energy distribution function is transient and the plasma is characterized by nonexponential growth of the electron density. For nitrogen, we show that the induction period is approximately equal to the inverse of the ionization frequency for a large E/N range. Time-dependent Boltzmann calculations of the electron energy distribution function yield instantaneous ionization rates that are in good agreement with both the measured ionization rates and the induction period. The measurements were made in an electrodeless cell contained in an S-band waveguide immersed in a dc magnetic field and subjected to a pulsed rf electric field at cyclotron resonance. We show that our measurements are equivalent to experiments in dc electric fields; the equivalent dc electric field strength being uniquely related to the rf electric field strength. The use of an rf field for these high-E/N measurements circumvents complications that would be introduced by electrode effects. This is the first direct measurement of ionization rates at these extreme values of E/N.

Hays, G.N.; Pitchford, L.C.; Gerardo, J.B.; Verdeyen, J.T.; Li, Y.M.

1987-09-01T23:59:59.000Z

337

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

338

Modeling Self-Ionized Plasma Wakefield Acceleration for Afterburner Parameters Using QuickPIC  

SciTech Connect (OSTI)

For the parameters envisaged in possible afterburner stages[1] of a plasma wakefield accelerator (PWFA), the self-fields of the particle beam can be intense enough to tunnel ionize some neutral gases. Tunnel ionization has been investigated as a way for the beam itself to create the plasma, and the wakes generated may differ from those generated in pre-ionized plasmas[2],[3]. However, it is not practical to model the whole stage of PWFA with afterburner parameters using the models described in [2] and [3]. Here we describe the addition of a tunnel ionization package using the ADK model into QuickPIC, a highly efficient quasi-static particle in cell (PIC) code which can model a PWFA with afterburner parameters. Comparison between results from OSIRIS (a full PIC code with ionization) and from QuickPIC with the ionization package shows good agreement. Preliminary results using parameters relevant to the E164X experiment and the upcoming E167 experiment at SLAC are shown.

Zhou, M.; Clayton, C.E.; Decyk, V.K.; Huang, C.; Johnson, D.K.; Joshi, C.; Lu, W.; Mori, W.B.; Tsung, F.S.; /UCLA; Deng, S.; Katsouleas, T.; Muggli, P.; Oz, E.; /Southern; Decker, F.-J.; Iverson, R.; O'Connel, C.; Walz, D.; /SLAC

2006-01-25T23:59:59.000Z

339

Method for the depth corrected detection of ionizing events from a co-planar grids sensor  

DOE Patents [OSTI]

A method for the detection of ionizing events utilizing a co-planar grids sensor comprising a semiconductor substrate, cathode electrode, collecting grid and non-collecting grid. The semiconductor substrate is sensitive to ionizing radiation. A voltage less than 0 Volts is applied to the cathode electrode. A voltage greater than the voltage applied to the cathode is applied to the non-collecting grid. A voltage greater than the voltage applied to the non-collecting grid is applied to the collecting grid. The collecting grid and the non-collecting grid are summed and subtracted creating a sum and difference respectively. The difference and sum are divided creating a ratio. A gain coefficient factor for each depth (distance between the ionizing event and the collecting grid) is determined, whereby the difference between the collecting electrode and the non-collecting electrode multiplied by the corresponding gain coefficient is the depth corrected energy of an ionizing event. Therefore, the energy of each ionizing event is the difference between the collecting grid and the non-collecting grid multiplied by the corresponding gain coefficient. The depth of the ionizing event can also be determined from the ratio.

De Geronimo, Gianluigi (Syosset, NY); Bolotnikov, Aleksey E. (South Setauket, NY); Carini, Gabriella (Port Jefferson, NY)

2009-05-12T23:59:59.000Z

340

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

SciTech Connect (OSTI)

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

Note: This page contains sample records for the topic "ionization brems pair" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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341

Photon-pair generation in nonlinear metal-dielectric 1D photonic structures  

E-Print Network [OSTI]

Nonlinear metal-dielectric layered structures are shown to be able to efficiently generate entangled photon pairs using spontaneous parametric down-conversion. Increase of electric-field amplitudes in these structures enhanced by the presence of metal layers is sufficient to compensate for losses inside thin metal layers. As an example, photon pairs emitted from a structure composed of alternating nonlinear dielectric GaN layers and metal Ag layers are analyzed in spectral, temporal as well as spatial domains. Also correlations and entanglement between two photons in a pair are determined. Very narrow photon-pair spectra together with strong directionality of photon-pair emission are observed making the photons suitable for photon-atom interactions. Highly enhanced electric-field amplitudes provide high photon-pair generation efficiencies.

Dalibor Jav?rek; Jan Pe?ina Jr.; Ji?í Svozilík

2014-10-16T23:59:59.000Z

342

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

343

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

344

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

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

345

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

SciTech Connect (OSTI)

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

346

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

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

347

Pair correlations in nuclei involved in neutrinoless double beta decay: 76Ge and 76Se  

E-Print Network [OSTI]

Precision measurements were carried out to test the similarities between the ground states of 76Ge and 76Se. The extent to which these two nuclei can be characterized as consisting of correlated pairs of neutrons in a BCS-like ground state was studied. The pair removal (p,t) reaction was measured at the far forward angle of 3 degrees. The relative cross sections are consistent (at the 5% level) with the description of these nuclei in terms of a correlated pairing state outside the N=28 closed shells with no pairing vibrations. Data were also obtained for 74Ge and 78Se.

S. J. Freeman; J. P. Schiffer; A. C. C. Villari; J. A. Clark; C. Deibel; S. Gros; A. Heinz; D. Hirata; C. L. Jiang; B. P. Kay; A. Parikh; P. D. Parker; J. Qian; K. E. Rehm; X. D. Tang; V. Werner; C. Wrede

2007-03-23T23:59:59.000Z

348

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

349

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

350

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

351

Development of Soft Ionization for Particulate Organic Detection with the Aerodyne Aerosol Mass Spectrometer  

SciTech Connect (OSTI)

During this DOE SBIR Phase II project, we have successfully developed several soft ionization techniques, i.e., ionization schemes which involve less fragmentation of the ions, for use with the Aerodyne time-of-flight aerosol mass spectrometer (ToF-AMS). Vacuum ultraviolet single photon ionization was demonstrated in the laboratory and deployed in field campaigns. Vacuum ultraviolet single photon ionization allows better identification of organic species in aerosol particles as shown in laboratory experiments on single component particles, and in field measurements on complex multi-component particles. Dissociative electron attachment with lower energy electrons (less than 30 eV) was demonstrated in the measurement of particulate organics in chamber experiments in Switzerland, and is now a routine approach with AMS systems configured for bipolar, negative ion detection. This technique is particularly powerful for detection of acidic and other highly oxygenated secondary organic aerosol (SOA) chemical functionality. Low energy electron ionization (10 to 12 eV) is also a softer ionization approach routinely available to AMS users. Finally, Lithium ion attachment has been shown to be sensitive to more alkyl-like chemical functionality in SOA. Results from Mexico City are particularly exciting in observing changes in SOA molecular composition under different photochemical/meteorological conditions. More recent results detecting biomass burns at the Montana fire lab have demonstrated quantitative and selective detection of levoglucosan. These soft ionization techniques provide the ToF-AMS with better capability for identifying organic species in ambient atmospheric aerosol particles. This, in turn, will allow more detailed study of the sources, transformations and fate of organic-containing aerosol.

Trimborn, A; Williams, L R; Jayne, J T; Worsnop, D R

2008-06-19T23:59:59.000Z

352

MULTI-DIMENSIONAL SIMULATIONS OF ROTATING PAIR-INSTABILITY SUPERNOVAE  

SciTech Connect (OSTI)

We study the effects of rotation on the dynamics, energetics, and {sup 56}Ni production of pair instability supernova (PISN) explosions by performing rotating two-dimensional ({sup 2}.5D{sup )} hydrodynamics simulations. We calculate the evolution of eight low-metallicity (Z = 10{sup –3}, 10{sup –4} Z{sub ?}) massive (135-245 M{sub ?}) PISN progenitors with initial surface rotational velocities of 50% of the critical Keplerian value using the stellar evolution code MESA. We allow for both the inclusion and the omission of the effects of magnetic fields in the angular momentum transport and in chemical mixing, resulting in slowly rotating and rapidly rotating final carbon-oxygen cores, respectively. Increased rotation for carbon-oxygen cores of the same mass and chemical stratification leads to less energetic PISN explosions that produce smaller amounts of {sup 56}Ni due to the effect of the angular momentum barrier that develops and slows the dynamical collapse. We find a non-monotonic dependence of {sup 56}Ni production on rotational velocity in situations when smoother composition gradients form at the outer edge of the rotating cores. In these cases, the PISN energetics are determined by the competition of two factors: the extent of chemical mixing in the outer layers of the core due to the effects of rotation in the progenitor evolution and the development of angular momentum support against collapse. Our 2.5D PISN simulations with rotation are the first presented in the literature. They reveal hydrodynamic instabilities in several regions of the exploding star and increased explosion asymmetries with higher core rotational velocity.

Chatzopoulos, E.; Wheeler, J. Craig [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Couch, Sean M., E-mail: manolis@astro.as.utexas.edu [Department of Astronomy and Astrophysics, Flash Center for Computational Science, University of Chicago, Chicago, IL 60637 (United States)

2013-10-20T23:59:59.000Z

353

Pair distribution function study on compression of liquid gallium  

SciTech Connect (OSTI)

Integrating a hydrothermal diamond anvil cell (HDAC) and focused high energy x-ray beam from the superconductor wiggler X17 beamline at the National Synchrotron Light Source (NSLS) at the Brookhaven National Laboratory (BNL), we have successfully collected high quality total x-ray scattering data of liquid gallium. The experiments were conducted at a pressure range from 0.1GPa up to 2GPa at ambient temperature. For the first time, pair distribution functions (PDF) for liquid gallium at high pressure were derived up to 10 {angstrom}. Liquid gallium structure has been studied by x-ray absorption (Di Cicco & Filipponi, 1993; Wei et al., 2000; Comez et al., 2001), x-ray diffraction studies (Waseda & Suzuki, 1972), and molecular dynamics simulation (Tsay, 1993; Hui et al., 2002). These previous reports have focused on the 1st nearest neighbor structure, which tells us little about the atomic arrangement outside the first shell in non- crystalline materials. This study focuses on the structure of liquid gallium and the atomic structure change due to compression. The PDF results show that the observed atomic distance of the first nearest neighbor at 2.78 {angstrom} (first G(r) peak and its shoulder at the higher Q position) is consistent with previous studies by x-ray absorption (2.76 {angstrom}, Comez et al., 2001). We have also observed that the first nearest neighbor peak position did not change with pressure increasing, while the farther peaks positions in the intermediate distance range decreased with pressure increasing. This leads to a conclusion of the possible existence of 'locally rigid units' in the liquid. With the addition of reverse Monte Carlo modeling, we have observed that the coordination number in the local rigit unit increases with pressure. The bulk modulus of liquid gallium derived from the volume compression curve at ambient temperature (300K) is 12.1(6) GPa.

Luo, Shengnian [Los Alamos National Laboratory; Yu, Tony [SUNY-SB; Chen, Jiuhua [SUNY-SB; Ehm, Lars [SUNY-SB; Guo, Quanzhong [SUNY-SB; Parise, John [SUNY-SB

2008-01-01T23:59:59.000Z

354

A CLUSTER PAIR: A3532 AND A3530  

SciTech Connect (OSTI)

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

355

Ionization distances of Rydberg atoms approaching solid surfaces in the presence of weak electric fields  

SciTech Connect (OSTI)

The ionization distances R{sub c}{sup I} of slow hydrogenlike Rydberg atoms approaching solid surfaces in the presence of a weak external electric field are calculated. The ionization is treated as resonant electron tunneling in the very vicinity of the top of the potential barrier, created between the ionic core and polarized solid. We obtain both the complex energies and the ionization distances by solving the energy eigenvalue problem under the outgoing wave boundary condition towards the solid. The eigenvalue problem is studied in parabolic coordinates within the framework of an etalon equation method adapted to include the confluence of turning points. It is demonstrated that in a critical region R{approx_equal}R{sub c}{sup I}>>1 a.u. of ion-surface distances R, parabolic quantum numbers n{sub 1}, n{sub 2}, and m can serve as approximate, but 'sufficiently good' quantum numbers, at least for lower n{sub 1} values. The method offers asymptotically exact analytical expressions for the ionization rates and energies, which follow the theoretical predictions of the complex scaling method (CSM). It is also found that the resulting ionization distances R{sub c}{sup I} are in very good agreement with the results of CSM. The implications of using obtained results in analyzing the recent xenon experimental data for R{sub c}{sup I} are briefly discussed.

Nedeljkovic, N.N.; Nedeljkovic, Lj.D. [Faculty of Physics, University of Belgrade, P.O. Box 368, Belgrade (Serbia and Montenegro)

2005-09-15T23:59:59.000Z

356

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

SciTech Connect (OSTI)

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

357

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

SciTech Connect (OSTI)

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

358

ISO spectroscopy of compact HII regions in the Galaxy. II Ionization and elemental abundances  

E-Print Network [OSTI]

Based on the ISO spectral catalogue of compact HII regions by Peeters et al. (2001), we present a first analysis of the hydrogen recombination and atomic fine-structure lines originated in the ionized gas. The sample consists of 34 HII regions located at galactocentric distances between Rgal = 0 and 15 kpc. The SWS HI recombination lines between 2 and 8 mum are used to estimate the extinction law at these wavelengths for 14 HII regions. An extinction in the K band between 0 and $\\sim$ 3 mag. has been derived. The fine-structure lines of N, O, Ne, S and Ar are detected in most of the sources. Most of these elements are observed in two different ionization stages probing a range in ionization potential up to 41 eV. The ISO data, by itself or combined with radio data taken from the literature, is used to derive the elemental abundances relative to hydrogen. The present data thus allow us to describe for each source its elemental abundance, its state of ionization and to constrain the properties of the ionizing star(s).

N. L. Martin-Hernandez; E. Peeters; C. Morisset; A. G. G. M. Tielens; P. Cox; P. R. Roelfsema; J. -P. Baluteau; D. Schaerer; J. S. Mathis; F. Damour; E. Churchwell; M. F. Kessler

2001-10-30T23:59:59.000Z

359

Non-equilibrium hydrogen ionization in 2D simulations of the solar atmosphere  

E-Print Network [OSTI]

The ionization of hydrogen in the solar chromosphere and transition region does not obey LTE or instantaneous statistical equilibrium because the timescale is long compared with important hydrodynamical timescales, especially of magneto-acoustic shocks. We implement an algorithm to compute non-equilibrium hydrogen ionization and its coupling into the MHD equations within an existing radiation MHD code, and perform a two-dimensional simulation of the solar atmosphere from the convection zone to the corona. Analysis of the simulation results and comparison to a companion simulation assuming LTE shows that: a) Non-equilibrium computation delivers much smaller variations of the chromospheric hydrogen ionization than for LTE. The ionization is smaller within shocks but subsequently remains high in the cool intershock phases. As a result, the chromospheric temperature variations are much larger than for LTE because in non-equilibrium, hydrogen ionization is a less effective internal energy buffer. The actual shock temperatures are therefore higher and the intershock temperatures lower. b) The chromospheric populations of the hydrogen n = 2 level, which governs the opacity of Halpha, are coupled to the ion populations. They are set by the high temperature in shocks and subsequently remain high in the cool intershock phases. c) The temperature structure and the hydrogen level populations differ much between the chromosphere above photospheric magnetic elements and above quiet internetwork. d) The hydrogen n = 2 population and column density are persistently high in dynamic fibrils, suggesting that these obtain their visibility from being optically thick in Halpha also at low temperature.

J. Leenaarts; M. Carlsson; V. Hansteen; R. J. Rutten

2007-09-24T23:59:59.000Z

360

Methods and composition for the production of orthogonal tRNA-aminoacyltRNA synthetase pairs  

DOE Patents [OSTI]

This invention provides compositions and methods for generating components of protein biosynthetic machinery including orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, and orthogonal pairs of tRNAs/synthetases. Methods for identifying orthogonal pairs are also provided. These components can be used to incorporate unnatural amino acids into proteins in vivo.

Schultz, Peter G. (La Jolla, CA); Wang, Lei (San Diego, CA); Anderson, John Christopher (San Diego, CA); Chin, Jason (Cambridge, GB); Liu, David R. (Lexington, MA); Magliery, Thomas J. (North Haven, CT); Meggers, Eric L. (Philadelphia, PA); Mehl, Ryan Aaron (Lancaster, PA); Pastrnak, Miro (San Diego, CA); Santoro, Steven William (Cambridge, MA); Zhang, Zhiwen (San Diego, CA)

2012-05-22T23:59:59.000Z

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

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

362

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.

363

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

364

K.K. Gan IPRD06 1 Bandwidths of Micro Twisted-Pair Cables  

E-Print Network [OSTI]

A or more What is rise/fall time after irradiation? What is optical power after irradiation? What currentK.K. Gan IPRD06 1 Bandwidths of Micro Twisted-Pair Cables and Fusion Spliced SIMM-GRIN Fibers Introduction Bandwidth of micro twisted-pair cables Bandwidth of fusion spliced SIMM-GRIN fibers Radiation

Gan, K. K.

365

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

366

A Paired-Vehicle Recourse Strategy for the Vehicle Routing Problem with Stochastic Demands  

E-Print Network [OSTI]

A Paired-Vehicle Recourse Strategy for the Vehicle Routing Problem with Stochastic Demands Aykagan Institute of Technology Abstract This paper presents a paired-vehicle recourse strategy for the vehicle vehicles is dispatched from a terminal to serve single-period customer demands which are known

Erera, Alan

367

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

SciTech Connect (OSTI)

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

368

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

369

Dissociative multiple ionization of diatomic molecules by extreme-ultraviolet free-electron-laser pulses  

SciTech Connect (OSTI)

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

370

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

371

Charge exchange and ionization cross sections of H{sup +}+H collision in dense quantum plasmas  

SciTech Connect (OSTI)

The plasma screening effects of dense quantum plasmas on H{sup +}+H charge exchange and ionization cross sections are calculated by the classical trajectory Monte Carlo method. For charge exchange cross sections, it is found that the screening effects reduce cross sections slightly in weak screening conditions. However, cross sections are reduced substantially in strong screening conditions. For ionization cross sections, with the increase of screening effects, cross sections for low energies increase more rapidly than those for high energies. When the screening effects are strong enough, it is found that ionization cross sections decrease with the increase of incident H{sup +} energy. In addition, the cross sections have been compared with those in weakly coupled plasmas. It is found that in weak screening conditions, plasma screening effects in the two plasmas are approximately the same, while in strong screening conditions, screening effects of dense quantum plasmas are stronger than those of weakly coupled plasmas.

Zhang, Ling-yu; Qi, Xin; Zhao, Xiao-ying; Meng, Dong-yuan; Xiao, Guo-qing [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China and University of Chinese Academy of Sciences, Beijing 100049 (China)] [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China and University of Chinese Academy of Sciences, Beijing 100049 (China); Duan, Wen-shan [Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou, Gansu 730070 (China)] [Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou, Gansu 730070 (China); Yang, Lei [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China and University of Chinese Academy of Sciences, Beijing 100049 (China) [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China and University of Chinese Academy of Sciences, Beijing 100049 (China); Department of Physics, Lanzhou University, Lanzhou 730000 (China)

2013-11-15T23:59:59.000Z

372

Calculating differential cross sections for electron-impact ionization without explicit use of the asymptotic form  

SciTech Connect (OSTI)

We describe the calculation of singly differential (energy-sharing) cross sections for electron-impact ionization. First, using exterior complex scaling, we calculate the outgoing portion of the scattering wave function without explicit use of asymptotic boundary conditions. Once that wave function is known for a finite region of space, the outgoing flux can be calculated and extrapolated to large distances according to behavior that is specific to the ionization problem. The differential cross section is proportional to the outgoing flux in specific directions of a hyperspherical angle in the coordinates. Calculations on the singlet s-wave radial limit (Temkin-Poet and collinear) models of electron-hydrogen atom ionization are presented. {copyright} {ital 1997} {ital The American Physical Society}

McCurdy, C.W. [Computing Sciences, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Computing Sciences, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Rescigno, T.N. [Physics and Space Technology Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)] [Physics and Space Technology Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

1997-12-01T23:59:59.000Z

373

Influence of ionization on reflection of solitary waves in a magnetized plasma  

SciTech Connect (OSTI)

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

374

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

375

On the ionizing continuum in active galactic nuclei: clues from ISO  

E-Print Network [OSTI]

The ISO coronal line spectrum of the brightest Seyfert galaxies from the CfA sample is presented and modeled. ISO observations of [O IV] 25.9 $\\mu$, [Ne V] 14.3 $\\mu$, [Mg VIII] 3.02 $\\mu$ and [Si IX] 2.58 $\\mu$ lines are presented; their relationship with the soft part of the ionizing spectrum from 50 to 300 eV is investigated. Pure photoionization models reproduce the line ratios, setting ranges for the ionization parameter and the optical depth of the emitting clouds. On the basis of the available data alone it is not possible to distinguish between a power-law or a blackbody distribution as the intrinsic shape of the UV ionizing spectrum. However, for the brightest Seyferts analyzed, namely, NGC 1068, Circinus and NGC 4151, a black-body UV continuum is favored.

M. Almudena Prieto; Sueli M. Viegas

1999-11-15T23:59:59.000Z

376

ARE MOLECULAR OUTFLOWS AROUND HIGH-MASS STARS DRIVEN BY IONIZATION FEEDBACK?  

SciTech Connect (OSTI)

The formation of massive stars exceeding 10 M {sub Sun} usually results in large-scale molecular outflows. Numerical simulations, including ionization, of the formation of such stars show evidence for ionization-driven molecular outflows. Here we examine whether the outflows seen in these models reproduce the observations. We compute synthetic ALMA and CARMA maps of CO emission lines of the outflows, and compare their signatures to existing single-dish and interferometric data. We find that the ionization-driven models can only reproduce weak outflows around high-mass star-forming regions. We argue that expanding H II regions probably do not represent the dominant mechanism for driving observed outflows. We suggest instead that observed outflows are driven by the collective action of the outflows from the many lower-mass stars that inevitably form around young massive stars in a cluster.

Peters, Thomas; Klessen, Ralf S. [Institut fuer Theoretische Astrophysik, Universitaet Heidelberg, Zentrum fuer Astronomie, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Klaassen, Pamela D. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Mac Low, Mordecai-Mark [Department of Astrophysics, American Museum of Natural History, 79th Street at Central Park West, New York, NY 10024-5192 (United States); Banerjee, Robi, E-mail: tpeters@physik.uzh.ch [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany)

2012-11-20T23:59:59.000Z

377

EFFECT OF COULOMB COLLISIONS ON THE GRAVITATIONAL SETTLING OF LOW AND HIGH FIRST IONIZATION POTENTIAL ELEMENTS  

SciTech Connect (OSTI)

We model the effect of gravitational settling in the upper chromosphere on O, Fe, Si, and Ne, studying whether Coulomb collisions between ionized low First Ionization Potential (FIP) elements and protons is sufficient to cause abundance enhancements relative to oxygen. We find that low-FIP abundance enhancements comparable to observed values can be obtained provided the hydrogen ionization degree lies in the approximate range 10%-30%, which agrees with chromospheric models. Lower or higher hydrogen ionization causes the FIP-effect to become smaller or absent (depletion of all heavy elements). Iron must be almost fully ionized in order to become enriched relative to high-FIP elements, and this requires a high iron photoionization rate. The time scale necessary to produce the enrichment increases rapidly with increasing H ionization. For iron in a background from a semiempirical chromospheric model, with an H ion fraction of the order of 30%-40% in the upper chromosphere, 1-2 hr of settling is required to produce enhancements comparable to observations. The absolute abundance (relative to H), which monotonically decreases with time during settling, has by that time decreased by less than 50% in the same altitude region. With the same background conditions, the silicon abundance is more strongly enhanced by the settling than the iron abundance. The high-FIP element neon is depleted, relative to O and low-FIP elements, in the same background and altitude region where iron is enhanced, typically by 50% or more relative to O after 1-2 hr of settling.

Bo, Iselin M. Th. [Piazza Europa 16, I-52026 Pian di Sco (Italy); Esser, Ruth [Institute of Science and Technology, University of Tromso, NO-9037 Tromso (Norway); Lie-Svendsen, Oystein, E-mail: iselinbo@online.no, E-mail: ruth.esser@uit.no, E-mail: Oystein.Lie-Svendsen@ffi.no [Norwegian Defence Research Establishment (FFI), P.O. Box 25, NO-2027 Kjeller (Norway)

2013-05-20T23:59:59.000Z

378

Effectiveness of projectile screening in single and multiple ionization of Ne by B{sup 2+}  

SciTech Connect (OSTI)

Pure multiple ionization cross sections of Ne by B{sup 2+} projectiles have been measured in the energy range of 0.75 to 4.0 MeV and calculated using the continuum distorted wave-eikonal initial state approximation. The experiment and calculations show that the ionization cross sections by B{sup 2+}, principally for the production of highly charged recoils, is strongly enhanced when compared to the bare projectile with the same charge state, He{sup 2+}, at the same velocities.

Wolff, W.; Luna, H.; Santos, A. C. F.; Montenegro, E. C. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, 21945-970 RJ (Brazil); DuBois, R. D. [Department of Physics, Missouri University of Science and Technology, Rolla, Missouri 65409 (United States); Montanari, C. C.; Miraglia, J. E. [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, C1428EGA, Buenos Aires (Argentina)

2011-10-15T23:59:59.000Z

379

Dressed-state strong-field approximation for laser-induced molecular ionization  

SciTech Connect (OSTI)

In the customary formulation of the strong-field approximation (SFA) for laser-induced ionization, the initial bound state is taken as field-free. In the formulation of a length-gauge SFA for ionization of a molecule described by a two-center binding potential with sufficiently large internuclear separation, we argue that the initial state has to be dressed in order to account for the different scalar potentials at the various centers. We propose a 'dressed-state' SFA to this end.

Becker, W. [Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin (Germany); Chen, J.; Chen, S. G. [Institute of Applied Physics and Computational Mathematics, P. O. Box 8009(28), 100088 Beijing (China); Milosevic, D. B. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo (Bosnia and Herzegowina); Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin (Germany)

2007-09-15T23:59:59.000Z

380

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

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

Hydrogen ions produced by plasma-assisted catalytic ionization using nickel grid  

SciTech Connect (OSTI)

Positive and negative hydrogen ions are produced by plasma-assisted catalytic ionization using a nickel grid, where the irradiation current density of positive ions onto the grid can be controlled by the discharge power. The irradiation energy can be controlled by both the grid potential and the discharge plasma potential. Extraction properties and energy distributions of positive and negative ions produced in the cases of using the grid and a porous nickel plate are compared. Two production mechanisms of negative ions are found in the process of plasma-assisted catalytic ionization.

Oohara, W.; Kawata, K.; Hibino, T. [Department of Electronic Device Engineering, Yamaguchi University, Ube 755-8611 (Japan)] [Department of Electronic Device Engineering, Yamaguchi University, Ube 755-8611 (Japan)

2013-06-15T23:59:59.000Z

382

Strong-field approximation for ionization of a diatomic molecule by a strong laser field. III. High-order above-threshold ionization by an elliptically polarized field  

SciTech Connect (OSTI)

We investigate high-order above-threshold ionization (HATI) of diatomic molecules having different symmetries by an elliptically polarized laser field using the modified molecular strong-field approximation. The yields of high-energy electrons contributing to the plateau region of the photoelectron spectra strongly depend on the employed ellipticity. This is more pronounced if the major axis of the polarization ellipse is parallel or perpendicular to the molecular axis and at the end of the high-energy plateau. For the O{sub 2} molecule (characterized by {pi}{sub g} symmetry) the maximum yield is observed for some value of the ellipticity {epsilon} different from zero. On the other hand, in the same circumstances, the N{sub 2} molecule ({sigma}{sub g}) behaves as an atom, i.e., the yield is maximum for {epsilon}=0. These characteristics of the photoelectron spectra remain valid in a wide region of the molecular orientations and laser peak intensities. The symmetry properties of the molecular HATI spectra are considered in detail: by changing the molecular orientation one or other type of the symmetry emerges or disappears. Presenting differential ionization spectra in the ionized electron energy-emission angle plane we have observed similar interference effects as in the HATI spectra governed by a linearly polarized field.

Busuladzic, M. [Medical Faculty, University of Sarajevo, Cekalusa 90, 71000 Sarajevo (Bosnia and Herzegowina); Gazibegovic-Busuladzic, A. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo (Bosnia and Herzegowina); Milosevic, D. B. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo (Bosnia and Herzegowina); Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin (Germany)

2009-07-15T23:59:59.000Z

383

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

384

Competing Pairing Symmetries in a Generalized Two-Orbital Model for the Pnictide Superconductors  

SciTech Connect (OSTI)

We introduce and study an extended t-U-J two-orbital model for the pnictides that includes Heisenberg terms deduced from the strong coupling expansion. Including these J terms explicitly allows us to enhance the strength of the %;0 - 0;% spin order which favors the presence of tightly bound pairing states even in the small clusters that are here exactly diagonalized. The A1g and B2g pairing symmetries are found to compete in the realistic spin-ordered and metallic regime. The dynamical pairing susceptibility additionally unveils low-lying B1g states, suggesting that small changes in parameters may render any of the three channels stable.

Nicholson, Andrew D [ORNL; Ge, Weihao [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Zhang, Xiaotian [Oak Ridge National Laboratory (ORNL); Riera, J. A. [Universidad Nacional de Rosario; Daghofer, M. [IFW Dresden; Olés, Andrzej M. [Max-Planck-Institut fur Feskorperforschung, Stuttgart, Germany; Martins, G. B. [Oakland University, Rochester, MI; Moreo, Adriana [ORNL; Dagotto, Elbio R [ORNL

2011-01-01T23:59:59.000Z

385

Superconductivity of a system with quasilocalized pairs taking account of inequivalence of sites  

SciTech Connect (OSTI)

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

386

Pairing states of superfluid {sup 3}He in uniaxially anisotropic aerogel  

SciTech Connect (OSTI)

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

387

PHYSICAL REVIEW A 87, 043407 (2013) Coherent control and giant enhancement of multiphoton ionization and high-order-harmonic  

E-Print Network [OSTI]

ionization and high-order-harmonic generation driven by intense frequency-comb laser fields: An ab initio investigation of the coherent control and significant enhancement of multiphoton ionization (MPI) and high-order-harmonic and molecular dynamics [28­30], and the generation of soft-x-ray attosecond pulses by high-order-harmonic

Chu, Shih-I

388

Human In vivo Dose-Response to Controlled, Low-Dose Low Linear EnergyTransfer Ionizing Radiation Exposure  

E-Print Network [OSTI]

Human In vivo Dose-Response to Controlled, Low-Dose Low Linear EnergyTransfer Ionizing Radiation Purpose: The effect of low doses of low ^ linear energy transfer (photon) ionizing radiation (LDIR, and pathway. Conclusions: These results show for the first time that low doses of radiation have an identifi

Rocke, David M.

389

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 2008; published 11 September 2008. [1] We present a new parameterization of the altitude profile of the ionization rate in the Earth's atmosphere due to precipitating energetic electrons. Precipitating electrons

Jackman, Charles H.

390

Multiple ionization of noble gases by swift H{sub 2}{sup +} ions in breakup and nonbreakup collisions  

SciTech Connect (OSTI)

We have measured multiple-ionization yields of He, Ne, Ar, Kr, and Xe targets by 1.0 MeV/amu H{sub 2}{sup +} molecular ions for both the dissociative and nondissociative channels. Except for the case of the breakup of the H{sub 2}{sup +} into two protons, we have also determined the absolute cross sections for the multiple ionization of the targets. The ratios of multiple to single ionization for the nondissociative channel are similar to those for equivelocity protons, which, however, are consistently smaller than those for the breakup channels, for all charge states and targets. A simple analysis, based on the independent particle model, considering postcollisional time-delayed ionization for the Ne and Ar targets, evinces the importance of these mechanisms in the target multiple ionization and of the antiscreening in collisions where the projectile electron undergoes a transition.

Sigaud, G.M.; Luna, H.; Montenegro, E.C. [Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, Caixa Postal 38071, Rio de Janeiro, RJ 22452-970 (Brazil); Sant'Anna, M.M.; Santos, A.C.F. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21941-972 (Brazil); McGrath, C.; Shah, M.B. [Department of Pure and Applied Physics, The Queen's University of Belfast, Belfast BT7 1NN (United Kingdom); Cavalcanti, E.G. [Instituto de Radioprotecao e Dosimetria, Comissao Nacional de Energia Nuclear, Rio de Janeiro, RJ 22780-160 (Brazil)

2004-06-01T23:59:59.000Z

391

Ionization energy shift of characteristic K x-ray lines from high-Z materials for plasma diagnostics  

SciTech Connect (OSTI)

The energy of the characteristic x-rays emitted by high atomic number atoms in a plasma that contains energetic electrons depends on the atom's ionization. For tungsten, the ionization energy shift of the L-lines has recently been used to diagnose the plasma's ionization; the change in energy of a K-line has been measured for iridium and observed for ytterbium. Here, we present detailed computations of the ionization energy shift to K-lines of these and an additional element, dysprosium; for these atoms, some K-lines nearly coincide in energy with K-edges of slightly lower Z atoms so that a change in transmission behind a K-edge filter betrays a change in energy. The ionization energy shift of such high-energy K-lines may enable a unique diagnostic when the plasma is inside an otherwise opaque enclosure such as hohlraums used on the National Ignition Facility.

S?abkowska, K.; Szyma?ska, E.; Polasik, M. [Faculty of Chemistry, Nicholas Copernicus University, 87-100 Toru? (Poland)] [Faculty of Chemistry, Nicholas Copernicus University, 87-100 Toru? (Poland); Pereira, N. R. [Ecopulse, Inc., 7844 Vervain Ct, Springfield, Virginia 22152 (United States)] [Ecopulse, Inc., 7844 Vervain Ct, Springfield, Virginia 22152 (United States); Rzadkiewicz, J. [National Centre for Nuclear Research, 05-400 Otwock (Poland)] [National Centre for Nuclear Research, 05-400 Otwock (Poland); Seely, J. F. [Artep, Inc., 2922 Excelsior Springs Ct, Ellicott, Maryland 21042 (United States)] [Artep, Inc., 2922 Excelsior Springs Ct, Ellicott, Maryland 21042 (United States); Weber, B. V.; Schumer, J. W. [Naval Research Laboratory, Washington, DC 20375 (United States)] [Naval Research Laboratory, Washington, DC 20375 (United States)

2014-03-15T23:59:59.000Z

392

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

393

Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Analysis of Large Polymerases Chain Reaction Products  

SciTech Connect (OSTI)

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

394

Exact theory and numeric results for short pulse ionization of simple model atom in one dimension  

E-Print Network [OSTI]

Our exact theory for continuous harmonic perturbation of a one dimensional model atom by parametric variations of its potential is generalized for the cases when a) the atom is exposed to short pulses of an external harmonic electric field and b) the forcing is represented by short bursts of different shape changing the strength of the binding potential. This work is motivated not only by the wide use of laser pulses for atomic ionization, but also by our earlier study of the same model which successfully described the ionization dynamics in all orders, i.e. the multi-photon processes, though being treated by the non-relativistic Schr\\"odinger equation. In particular, it was shown that the bound atom cannot survive the excitation of its potential caused by any non-zero frequency and amplitude of the continuous harmonic forcing. Our present analysis found important laws of the atomic ionization by short pulses, in particular the efficiency of ionizing this model system and presumably real ones as well.

Rokhlenko, Alexander

2015-01-01T23:59:59.000Z

395

Programs for Laser-AO Assisted Integral-Field Spectrometers on Ionized Flows  

E-Print Network [OSTI]

(starburst galaxies) or by gas accretion (Herbig-Haro object [HHO] flows and AGN). I introduce some-Haro Outflows HHO's are second only to supernova remnants as laboratories for study of non- planar astrophysical shocks. Ionization is entirely local in HHO shocks. Because only the component of motion perpendicular

Cecil, Gerald

396

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.

397

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

398

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

399

Detection of Ionizing Radiation by Plasma-Panel Sensors: Cosmic Muons, Ion Beams, and Cancer Therapy  

SciTech Connect (OSTI)

The plasma panel sensor is an ionizing photon and particle radiation detector derived from PDP technology with high gain and nanosecond response. Experimental results in detecting cosmic ray muons and beta particles from radioactive sources are described along with applications including high energy and nuclear physics, homeland security and cancer therapeutics.

Friedman, Dr. Peter S. [Integrated Sensors, LLC; Ferretti, Claudio [University of Michigan; Ball, Robert [University of Michigan; Beene, James R [ORNL; Ben Moshe, M. [Tel Aviv University; Benhammou, Yan [Tel Aviv University; Chapman, J. Wehrley [University of Michigan; Levin, Daniel S. [University of Michigan; Silver, Yiftah [Tel Aviv University; Weaverdyck, Curtis [University of Michigan; Zhou, Bing [University of Michigan; Etzion, E [Tel Aviv University; Moshe, M. [Tel Aviv University; Bentefour, E [Ion Beam Applications

2012-01-01T23:59:59.000Z

400

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

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

Sequential Treatment by Ionizing Radiation and Sodium Arsenite Dramatically Accelerates TRAIL-Mediated Apoptosis of  

E-Print Network [OSTI]

is critically important in the translocation of death receptor to the cell surface. Moreover, sodium arsenite and further down-regulates cFLIP levels in melanoma cells. We have evaluated the effects of sequentialSequential Treatment by Ionizing Radiation and Sodium Arsenite Dramatically Accelerates TRAIL

402

Mammalian Tissue Response to Low Dose Ionizing Radiation: The Role of Oxidative Metabolism and Intercellular Communication  

SciTech Connect (OSTI)

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

403

Supplementary Information for Field Ionization of Cold Atoms Near the Wall of a Single Carbon Nanotube  

E-Print Network [OSTI]

1 Supplementary Information for Field Ionization of Cold Atoms Near the Wall of a Single Carbon with suspended nanotubes. Single-walled carbon nanotubes, suspended across 10-m gaps, are grown on silicon chips is applied with clip connections to the pads. The electrode design was optimized with numerical modelling

Hau, Lene Vestergaard

404

Development of Pattern Recognition Software for Tracks of Ionizing Radiation In Medipix2-Based  

E-Print Network [OSTI]

by a TimePix version of the hybrid semiconductor Medipix2 pixel detector system. Such a software tool would predict the type of source of radiation captured by the pixel detector device. Such tool would bridge classification of sources of ionizing radiation as captured by the hybrid semiconductor pixel detector Medipix2

Vilalta, Ricardo

405

Ionized physical vapor deposition of integrated circuit interconnects* J. Hopwood,a)  

E-Print Network [OSTI]

Ionized physical vapor deposition of integrated circuit interconnects* J. Hopwood,a) Northeastern University, Boston, Massachusetts 02115 Received 19 November 1997; accepted 25 November 1997 Interconnects to the interconnection of semiconductor devices while the remaining 10 percent is due to transistor-related delay

406

Molecular Resolution and Fragmentation of Fulvic Acid by Electrospray Ionization/Multistage Tandem  

E-Print Network [OSTI]

investigated by electrospray ionization/ion trap multistage tandem mass spectrometry (ESI/MST/ MS). ESI% water mobile phase found that negative ion detection gave the optimum generation of parent ions that can and specific high molecular weight standards found multiply charged negative ions that gave a low bias

407

THE IMPACT OF NEW IONIZING FLUXES ON ISO OBSERVATIONS OF HII REGIONS AND STARBURSTS \\Lambda  

E-Print Network [OSTI]

1 THE IMPACT OF NEW IONIZING FLUXES ON ISO OBSERVATIONS OF HII REGIONS AND STARBURSTS \\Lambda on the IR lines are shown. First comparisons of our starburst models with IR­diagnostics and the ISO observations of Genzel et al. (1998) are also presented. Key words: HII regions, galaxies: starburst, ISO. 1

Schaerer, Daniel

408

Charge symmetric dissociation of doubly ionized N{sub 2} and CO molecules  

SciTech Connect (OSTI)

We report a comparative study of the features in dissociative double ionization by high energy electron impact of N{sub 2} and CO molecules. The ratio of cross-section of charge symmetric dissociative ionization to non-dissociative ionization (CSD-to-ND ratio) and the kinetic energy release (KER) spectra of dissociation are experimentally measured and carefully corrected for various ion transmission losses and detector inefficiencies. Given that the double ionization cross sections of these iso-electronic diatomics are very similar, the large difference in the CSD-to-ND ratios must be attributable to the differences in the evolution dynamics of the dications. To understand these differences, potential energy curves (PECs) of dications have been computed using multi-reference configuration interaction method. The Franck-Condon factors and tunneling life times of vibrational levels of dications have also been computed. While the KER spectrum of N{sub 2}{sup ++} can be readily explained by considering dissociation via repulsive states and tunneling of meta-stable states, indirect dissociation processes such as predissociation and autoionization have to be taken into account to understand the major features of the KER spectrum of CO{sup ++}. Direct and indirect processes identified on the basis of the PECs and experimental KER spectra also provide insights into the differences in the CSD-to-ND ratios.

Pandey, A., E-mail: amrendra@prl.res.in; Bapat, B. [Physical Research Laboratory, Ahmedabad 380009 (India)] [Physical Research Laboratory, Ahmedabad 380009 (India); Shamasundar, K. R. [Indian Institute of Science Education and Research, Mohali, Sector 81, SAS Nagar 140306 (India)] [Indian Institute of Science Education and Research, Mohali, Sector 81, SAS Nagar 140306 (India)

2014-01-21T23:59:59.000Z

409

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 that would be most desired. Using the pro- pane gas jet, as opposed to pure hydrogen, eased conditions on the gas jet nozzle, since a lower gas pressure could pro- duce a higher density target. However, the use

410

Identifying the Proteins that Mediate the Ionizing Radiation Resistance of Deinococcus Radiodurans R1  

SciTech Connect (OSTI)

The primary objectives of this proposal was to define the subset of proteins required for the ionizing radiation (IR) resistance of Deinococcus radiodurans R1, characterize the activities of those proteins, and apply what was learned to problems of interest to the Department of Energy.

Battista, John R

2010-02-22T23:59:59.000Z

411

Laser Desorption Single-Photon Ionization of Asphaltenes: Mass Range, Compound Sensitivity, and Matrix Effects  

E-Print Network [OSTI]

Laser Desorption Single-Photon Ionization of Asphaltenes: Mass Range, Compound Sensitivity-level characterization of petroleum asphaltenes is important for addressing reservoir concerns such as connectivity as a favored technique for asphaltene analysis, because of its ability to detect these samples with minimal

Zare, Richard N.

412

Ionization Spectroscopy of Conformational Isomers of Propanal: The Origin of the Conformational Preference  

E-Print Network [OSTI]

Ionization Spectroscopy of Conformational Isomers of Propanal: The Origin of the Conformational conformational isomers of propanal, cis and gauche, are investigated by the vacuum-UV mass- analyzed thresholdV and 9.9516 ( 0.0006 eV, respectively. cis-Propanal, which is the more stable conformer in the neutral

Kim, Sang Kyu

413

Nucleon and nucleon-pair momentum distributions in A?12 nuclei  

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

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

414

Pairing preferences of the model mono-valence mono-atomic ions investigated by molecular simulation  

SciTech Connect (OSTI)

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

415

E-Print Network 3.0 - anionic ion-pairing reagent Sample Search...  

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

The Role of HMPA Summary: structure of the lithium reagent, where contact ion pairs (CIP) with an intact C-Li association give 1... ,3 Bryson3b and Cohen3a have proposed that...

416

Optical AND and NOT gates at 40 Gbps using electro-absorption modulator/photodiode pairs.  

SciTech Connect (OSTI)

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

417

Production of meson pairs, involving tensor and pseudotensor mesons, in photon-photon collisions  

E-Print Network [OSTI]

Starting from a bound-state model of weakly bound quarks for ($q \\bar{q}$) mesons, we derive a formalism for computing the production or decay of such mesons, whatever the value of their internal orbital angular momentum L. That formalism appears as a natural generalization of the Brodsky-Lepage model (valid only for L=0) that has been widely used in recent years for the computation of exclusive processes in perturbative QCD. We here apply it to the production, in photon-photon collisions, of: i) tensor-meson pairs; ii) pseudotensor-meson pairs; iii) hybrid pairs made of a pion and a pseudotensor meson. The numerical results we obtain allow for some hope of experimentally identifying such pairs, in the charged channels, at high-energy e^+e^- colliders of the next generation, provided integrated luminosities as high as

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

1996-01-01T23:59:59.000Z

418

Molecular Recognition of Alkylammonium Contact Ion-Pairs Using a Ditopic Receptor  

E-Print Network [OSTI]

-propylammonium chloride is at least 2 orders of magnitude greater than that for n-propylammonium acetate, n-pairs (Chart 1).10 Here, we report that 1 can also bind monoalkylammo- nium salts as contact ion

Smith, Bradley D.

419

Plasmon decay to a neutrino pair via neutrino electromagnetic moments in a strongly magnetized medium  

E-Print Network [OSTI]

We calculate the neutrino luminosity of a degenerate electron gas in a strong magnetic field via plasmon decay to a neutrino pair due to neutrino electromagnetic moments and obtain the relative upper bounds on the effective neutrino magnetic moment.

A. V. Borisov; P. E. Sizin

2014-06-12T23:59:59.000Z

420

Interactions in 1-ethyl-3-methyl imidazolium tetracyanoborate ion pair: Spectroscopic and density functional study  

SciTech Connect (OSTI)

Density Functional Theory is used to investigate a weakly coordinating room-temperature ionic liquid, 1-ethyl-3-methyl imidazolium tetracyanoborate ([Emim]{sup +}[TCB]{sup -}). Four locally stable conformers of the ion pair were located. Atoms-in-molecules (AIM) and electron density analysis indicated the existence of several hydrogen bonds. Further investigation through the Natural Bond Orbital (NBO) and Natural Energy Decomposition Analysis (NEDA) calculations provided insight into the origin of interactions in the [Emim]{sup +}[TCB]{sup -} ion pair. Strength of molecular interactions in the ionic liquid was correlated with frequency shifts of the characteristic vibrations of the ion pair. Harmonic vibrations of the ion pair were also compared with the experimental Raman and Infrared spectra. Vibrational frequencies were assigned by visualizing displacements of atoms around their equilibrium positions and through Potential Energy Distribution (PED) analysis.

Mao, James X.; Lee, Anita S.; Kitchin, John R.; Nulwala, Hunaid B; Luebke, David R.; Damodaran, Krishnan

2013-04-24T23:59:59.000Z

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

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

422

Parallel Assembly of Large Genomes from Paired Short Reads (2010 JGI/ANL HPC Workshop)  

ScienceCinema (OSTI)

Srinivas Aluru from Iowa State University gives a presentation on "Parallel Assembly of Large Genomes from Paired Short Reads" at the JGI/Argonne HPC Workshop on January 25, 2010.

Aluru, Srinivas [Iowa State University

2011-06-08T23:59:59.000Z

423

Calculation of the entropy of binary hard sphere mixtures from pair correlation functions  

E-Print Network [OSTI]

We evaluate the entropy of several binary hard sphere fluid mixtures using two approximate expressions that require as input only the pair correlation functions,g ??(r). An approximation based on the incompressible limit ...

Laird, Brian Bostian; Haymet, A. D. J.

1992-06-01T23:59:59.000Z

424

First Measurement of the Charge Asymmetry in Beauty-Quark Pair Production  

E-Print Network [OSTI]

The difference in the angular distributions between beauty quarks and antiquarks, referred to as the charge asymmetry, is measured for the first time in b[bar over b] pair production at a hadron collider. The data used ...

Counts, Ian Thomas Hunt

425

On existence of solitary waves in unmagnetized neutral hot pair plasma  

SciTech Connect (OSTI)

Whether the solitary waves exist in unmagnetized neutral hot pair plasma is considered. It is found that for small electrons and positrons longitudinal momentum the solitary waves do not exist under the quasi-static approximation.

Xie, Bai-Song; Li, Zi-Liang; Lu, Ding; Sang, Hai-Bo [Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, and College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China)] [Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, and College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China)

2013-11-15T23:59:59.000Z

426

Pair correlations in the neutrinoless double-{beta} decay candidate {sup 130}Te  

SciTech Connect (OSTI)

Pair correlations in the ground state of {sup 130}Te have been investigated using pair-transfer experiments to explore the validity of approximations in calculating the matrix element for neutrinoless double-{beta} decay. This nucleus is a candidate for the observation of such decay, and a good understanding of its structure is crucial for eventual calculations of the neutrino mass, should such a decay indeed be observed. For proton-pair adding, strong transitions to excited 0{sup +} states had been observed in the Te isotopes by Alford et al. [Nucl. Phys. A 323, 339 (1979)], indicating a breaking of the BCS approximation for protons in the ground state. We measured the neutron-pair removing (p,t) reaction on {sup 130}Te and found no indication of a corresponding splitting of the BCS nature of the ground state for neutrons.

Bloxham, T.; Freedman, S. J. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Kay, B. P.; Schiffer, J. P.; Clark, J. A. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Deibel, C. M. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48825 (United States); Freeman, S. J.; Howard, A. M.; McAllister, S. A.; Sharp, D. K.; Thomas, J. S. [Schuster Laboratory, University of Manchester, Manchester, M13 9PL (United Kingdom); Parker, P. D. [A. W. Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520 (United States)

2010-08-15T23:59:59.000Z

427

Pair correlations in neutrinoless double {beta} decay candidate {sup 130}Te.  

SciTech Connect (OSTI)

Pair correlations in the ground state of {sup 130}Te have been investigated using pair-transfer experiments to explore the validity of approximations in calculating the matrix element for neutrinoless double-{beta} decay. This nucleus is a candidate for the observation of such decay, and a good understanding of its structure is crucial for eventual calculations of the neutrino mass, should such a decay indeed be observed. For proton-pair adding, strong transitions to excited 0{sup +} states had been observed in the Te isotopes by Alford et al. [Nucl. Phys. A 323, 339 (1979)], indicating a breaking of the BCS approximation for protons in the ground state. We measured the neutron-pair removing (p,t) reaction on {sup 130}Te and found no indication of a corresponding splitting of the BCS nature of the ground state for neutrons.

Bloxham, T.; Kay, B. P.; Schiffer, J. P.; Clark, J. A.; Deibel, C. M.; Freeman, S. J.; Freedman, S. J.; Howard, A. M.; McAllister, S. A.; Parker, P. D.; Sharp, D. K.; Thomas, J. S. (Physics); ( PSC-USR); (LBNL); (Michigan State Univ.); (Univ. of Manchester); (Yale Univ.)

2010-08-16T23:59:59.000Z

428

WHEN A PAIR of nuclear-powered Russian submarines was reported patrolling  

E-Print Network [OSTI]

WHEN A PAIR of nuclear-powered Russian submarines was reported patrolling off the eastern seaboard as "explaining-away." Although several algorithms were later developed to perform Bayesian updating in general

California at Los Angeles, University of

429

Thesis for the Degree of Licentiate of Philosophy TwoLocus Affected SibPair  

E-Print Network [OSTI]

Thesis for the Degree of Licentiate of Philosophy Two­Locus Affected Sib­Pair Identity By Descent­time arrangement. This licentiate thesis has been financially supported by the National Network in Applied

Patriksson, Michael

430

Study of nuclear pairing with Configuration-Space Monte-Carlo approach  

E-Print Network [OSTI]

Pairing correlations in nuclei play a decisive role in determining nuclear drip-lines, binding energies, and many collective properties. In this work a new Configuration-Space Monte-Carlo (CSMC) method for treating nuclear pairing correlations is developed, implemented, and demonstrated. In CSMC the Hamiltonian matrix is stochastically generated in Krylov subspace, resulting in the Monte-Carlo version of Lanczos-like diagonalization. The advantages of this approach over other techniques are discussed; the absence of the fermionic sign problem, probabilistic interpretation of quantum-mechanical amplitudes, and ability to handle truly large-scale problems with defined precision and error control, are noteworthy merits of CSMC. The features of our CSMC approach are shown using models and realistic examples. Special attention is given to difficult limits: situations with non-constant pairing strengths, cases with nearly degenerate excited states, limits when pairing correlations in finite systems are weak, and pr...

Lingle, Mark

2015-01-01T23:59:59.000Z

431

Short-term irradiance variability: Preliminary estimation of station pair correlation as a function of distance  

E-Print Network [OSTI]

Review Short-term irradiance variability: Preliminary estimation of station pair correlation, 2010; SMUD, 2010; IEA, 2010). In a recently published article, Hoff and Perez (2010a,b) advanced

432

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

433

INTRODUCTION Meiosis is the specialized pair of cell divisions that normally  

E-Print Network [OSTI]

(FISH) were used to localize a single pair of homologs in diploid nuclei of a chromosome-addition line of FISH signals. Using a triple labeling scheme for simultaneous imaging of chromatin, telomeres Hank W. Bass1,2,*, Osc

Bass, Hank W.

434

PHYSICAL REVIEW B 86, 195103 (2012) Dynamics of doublon-holon pairs in Hubbard two-leg ladders  

E-Print Network [OSTI]

PHYSICAL REVIEW B 86, 195103 (2012) Dynamics of doublon-holon pairs in Hubbard two-leg ladders Luis of holon-doublon pairs is studied in Hubbard two-leg ladders using the time-dependent density matrix of a doublon-holon pair. Two distinct regimes are identified. For weak interleg coupling, the results

Dias, Luis Gregório

435

Electron-Positron Pair Production in Space- or Time-Dependent Electric Fields  

E-Print Network [OSTI]

Treating the production of electron and positron pairs by a strong electric field from the vacuum as a quantum tunneling process we derive, in semiclassical approximation, a general expression for the pair production rate in a $z$-dependent electric field $E(z)$ pointing in the $z$-direction. We also allow for a smoothly varying magnetic field parallel to $E(z)$. The result is applied to a confined field $E(z)\

Hagen Kleinert; Remo Ruffini; She-Sheng Xue

2008-07-06T23:59:59.000Z

436

A 500 kpc HI Tail of the Virgo Pair NGC4532/DDO137 Detected by ALFALFA  

E-Print Network [OSTI]

HI observations of the Virgo Cluster pair NGC 4532/DDO 137, conducted as part of the Arecibo Legacy Fast ALFA Survey (ALFALFA), reveal an HI feature extending ~500 kpc to the southwest. The structure has a total mass of up to 7 x 10^8 solar masses, equivalent to 10% of the pair HI mass. Optical R imaging reveals no counterparts to a level of 26.5 magnitudes per square arcsec. The structure is likely the result of galaxy harassment.

Rebecca A. Koopmann

2007-07-22T23:59:59.000Z

437

A 500 kpc HI Tail of the Virgo Pair NGC4532/DDO137 Detected by ALFALFA  

E-Print Network [OSTI]

HI observations of the Virgo Cluster pair NGC 4532/DDO 137, conducted as part of the Arecibo Legacy Fast ALFA Survey (ALFALFA), reveal an HI feature extending ~500 kpc to the southwest. The structure has a total mass of up to 7 x 10^8 solar masses, equivalent to 10% of the pair HI mass. Optical R imaging reveals no counterparts to a level of 26.5 magnitudes per square arcsec. The structure is likely the result of galaxy harassment.

Koopmann, Rebecca A

2007-01-01T23:59:59.000Z

438

K.K. Gan IWORID-8 1 Bandwidths of Micro Twisted-Pair Cables  

E-Print Network [OSTI]

-V Characteristics very good optical power candidate for irradiation study Optowell TP85-LCP0N 0.0 0.5 1.0 1.5 2K.K. Gan IWORID-8 1 Bandwidths of Micro Twisted-Pair Cables and Fusion Spliced SIMM-GRIN Fibers Bandwidth of micro twisted-pair cables Bandwidth of fusion spliced SIMM-GRIN fibers Measurement of VCSEL

Gan, K. K.

439

Energy Levels of Odd-Odd nuclei Using Broken Pair Model  

E-Print Network [OSTI]

Simple methods in the frame work of the broken pair model have been worked out for odd-odd nuclei. The reliability of the model has been tested by reproducing the shell model results of limiting cases in which the broken pair model exactly coincides with the shell model. The model is then applied to calculate the energy levels of some nuclei in the Zirconium region. The model results compare reasonably well with the shell model as well as with the experimental data.

I. M. Hamammu; S. Haq; J. M. Eldahomi

2007-02-02T23:59:59.000Z

440

Weak-localization, near-magnetism, and triplet-pairing superconductivity in three dimensions  

SciTech Connect (OSTI)

In three-dimensional nearly magnetic Fermi liquids, disorder due to impurity scattering is shown to enhance the paramagnon strength and to weaken the triplet superconductivity pair-breaking parameter (through weak-localization quantum effects). As a result (a) ''heavy fermion'' superconductors are good candidates to exhibit triplet pairing and (b) normal liquid /sup 3/He can be considered as both nearly magnetic and nearly localized.

Beal-Monod, M.T.

1985-02-01T23:59:59.000Z

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.


441

Electron-positron pair oscillation in spatially inhomogeneous electric fields and radiation  

E-Print Network [OSTI]

It is known that strong electric fields produce electron and positron pairs from the vacuum, and due to the back-reaction these pairs oscillate back and forth coherently with the alternating electric fields in time. We study this phenomenon in spatially inhomogeneous and bound electric fields by integrating the equations of energymomentum and particle-number conservations and Maxwell equations. The space and time evolutions of the pair-induced electric field, electric charge- and currentdensities are calculated. The results show that non-vanishing electric charge-density and the propagation of pair-induced electric fields, differently from the case of homogeneous and unbound electric fields. The space and time variations of pair-induced electric charges and currents emit an electromagnetic radiation. We obtain the narrow spectrum and intensity of this radiation, whose peak {\\omega}peak locates in the region around 4 KeV for electric field strength \\sim Ec. We discuss their relevances to both the laboratory experiments for electron and positron pair-productions and the astrophysical observations of compact stars with an electromagnetic structure.

Wen-Biao Han; Remo Ruffini; She-Sheng Xue

2010-06-11T23:59:59.000Z

442

Parity mixing of pair at nuclear surface due to spin-orbit potential in $^{18}$F  

E-Print Network [OSTI]

We investigate the structure of $^{18}$F with the microscopic wave function based on the three-body $^{16}$O+$p$+$n$ model. In the calculation of the generator coordinate method (GCM) of the three-body model, $T=0$ energy spectra of $J^\\pi=1^+$, $3^+$, and $5^+$ states and $T=1$ spectra of $J^\\pi=0^+$, $2^+$ states in $^{18}$F are described reasonably. Based on the dinucleon picture, the effect of the spin-orbit force on the $T=0$ and $T=1$ $pn$ pairs around the $^{16}$O core is discussed. The $T=1$ pair in the $J^\\pi=0^+$ state gains the spin-orbit potential energy involving the odd-parity mixing in the pair. The spin-orbit potential energy gain with the parity mixing is not so efficient for the $T=0$ pair in the $J^\\pi=1^+$ state. The parity mixing in the pair is regarded as the internal symmetry breaking of the pair in the spin-orbit potential at the nuclear surface.

Yoshiko Kanada-En'yo; Fumiharu Kobayashi

2014-07-01T23:59:59.000Z

443

Optical Flashes from Internal Pairs Formed in Gamma-Ray Burst Afterglows  

E-Print Network [OSTI]

We develop a numerical formalism for calculating the distribution with energy of the (internal) pairs formed in a relativistic source from unscattered MeV--TeV photons. For GRB afterglows, this formalism is more suitable if the relativistic reverse-shock that energizes the ejecta is the source of the GeV photons. The number of pairs formed is set by the source GeV output (calculated from the Fermi-LAT fluence), the unknown source Lorentz factor, and the unmeasured peak energy of the LAT spectral component. We show synchrotron and inverse-Compton light-curves expected from pairs formed in the shocked medium and identify some criteria for testing a pair origin of GRB optical counterparts. Pairs formed in bright LAT afterglows with a Lorentz factor in the few hundreds may produce bright optical counterparts (R < 10) lasting for up to one hundred seconds. The number of internal pairs formed from unscattered seed photons decreases very strongly with the source Lorentz factor, thus bright GRB optical counterpart...

Panaitescu, A

2015-01-01T23:59:59.000Z

444

BeppoSAX spectroscopy of MR 2251-178: a test for ionized reflection in radio quiet QSOs  

E-Print Network [OSTI]

We present the 0.1-200 keV BeppoSAX spectrum of MR 2251-178 observed at two epochs in 1998 separated by 5 months. Both epochs show identical spectral shape and X-ray flux. Analysis of the combined spectra allow us to confirm the presence of the ionized Fe K-alpha line detected by ASCA and to test the presence of reflection from ionized material. The best self-consistent spectral fit is obtained when including a contribution from a mildly ionized reflector (Xi(0.01-100) ~ 1625 erg cm s-1, i.e. U(0.1-10) ~ 0.14) with a reflection fraction R_ion ~ 0.11. An exponential cut-off to the direct power-law continuum is then required at E ~ 100 keV. The low energy spectrum is absorbed by ionized matter with a column density N_W = (8.1 (-1.2/+2.1))*10^21 cm^-2 and an X-ray ionization parameter U(0.1-10)= 0.06 +/- 0.01. The warm absorber column is slightly lower than that measured with ASCA. This change could be caused by bulk motion. The BeppoSAX absorber ionization parameter globally agrees with the ``U versus Flux'' correlation found for MR 2251-178 with EXOSAT, Ginga and ASCA. This suggests that the absorber is in a state of instantaneous ionization equilibrium.

A. Orr; P. Barr; M. Guainazzi; A. N. Parmar; A. J. Young; ;

2001-07-19T23:59:59.000Z

445

Possible Effects of Pair Echoes on Gamma-Ray Burst Afterglow Emission  

E-Print Network [OSTI]

High-energy emission from gamma-ray bursts (GRBs) is widely expected but had been sparsely observed until recently when the Fermi satellite was launched. If >TeV gamma rays are produced in GRBs and can escape from the emission region, they are attenuated by the cosmic infrared background photons, leading to regeneration of GeV-TeV secondary photons via inverse-Compton scattering. This secondary emission can last for a longer time than the duration of GRBs, and it is called a pair echo. We investigate how this pair echo emission affects spectra and light curves of high energy afterglows, considering not only prompt emission but also afterglow as the primary emission. Detection of pair echoes is possible as long as the intergalactic magnetic field (IGMF) in voids is weak. We find (1) that the pair echo from the primary afterglow emission can affect the observed high-energy emission in the afterglow phase after the jet break, and (2) that the pair echo from the primary prompt emission can also be relevant, but only when significant energy is emitted in the TeV range, typically E_{gamma, >0.1 TeV} > (Y/(1+Y)) epsilon_e E_k. Even non-detections of the pair echoes could place interesting constraints on the strength of IGMF. The more favorable targets to detect pair echoes may be the "naked" GRBs without conventional afterglow emission, although energetic naked GRBs would be rare. If the IGMF is weak enough, it is predicted that the GeV emission extends to >30-300 s.

Kohta Murase; Bing Zhang; Keitaro Takahashi; Shigehiro Nagataki

2009-02-27T23:59:59.000Z

446

Hole pairing from attraction of opposite chirality spin vortices: Non-BCS superconductivity in Underdoped Cuprates  

E-Print Network [OSTI]

Within a gauge approach to the t-J model, we propose a new, non-BCS mechanism of superconductivity for underdoped cuprates. We implement the no-double occupancy constraint with a (semionic) slave-particle formalism. The dopant generates a vortex-like quantum distortion of the AF background centered on the empty sites, with opposite chirality for cores on the two N\\'eel sublattices. Empty sites are described in terms of spinless fermionic holons and the long-range attraction between spin vortices on two opposite N\\'eel sublattices is the holon pairing force, leading eventually to SC. The spin fluctuations are described by bosonic spinons with a gap generated by scattering on spin vortices. Due to the occupation constraint, there is a gauge attraction between holon and spinon, binding them into a physical hole. Through gauge interaction the spin vortex attraction induces the formation of spin-singlet RVB pairs reducing the spinon gap. Lowering T, there are two crossovers as precursors of the SC transition: at the higher one a gas of holon pairs appears, reducing the hole spectral weight, while at the lower one a gas of spinon pairs also appears, giving rise to a gas of incoherent preformed hole pairs with magnetic vortices in the plasma phase, supporting a Nernst signal. At an even lower T the hole pairs become coherent and SC appears beyond a critical doping. The proposed SC mechanism is not of the BCS-type, because it involves a gain in kinetic energy (lowering of spinon gap) and it is "almost" of the classical 3D XY-type. Since both the spinon gap and the holon pairing originate from the same term in the slave-particle representation of the t-J model, this approach incorporates a strong interplay between AF and SC, giving rise to a universal relation between Tc and the energy of the resonance mode, as observed in neutron scattering experiments.

P. A. Marchetti; F. Ye; Z. B. Su; L. Yu

2011-05-25T23:59:59.000Z

447

Comparative study of ionization chamber detectors vis-a-vis a CCD detector for dispersive XAS measurement in transmission geometry  

SciTech Connect (OSTI)

We have designed and fabricated parallel plate ionization chamber detectors and voltage vs. current characteristics (V-I curve) of the detectors were recorded with synchrotron radiation to qualify for use in X-ray Absorption Spectroscopy (XAS) measurements. After qualifying the ionization chambers, the detectors were used in the dispersive EXAFS beamline (BL-08) at INDUS-2 SRS in Turbo-XAS geometry. Using the same setup and under the same setting, XAS spectra were also recorded with a CCD detector and the observation on relative performance of the ionization chamber vis-a-vis the CCD detector is presented in this paper.

Poswal, A. K.; Agrawal, A.; Bhattachryya, D.; Jha, S. N.; Sahoo, N. K. [Applied Spectroscopy Division, Bhabha Atomic Research Centre, Mumbai -400 085 (India)

2013-02-05T23:59:59.000Z

448

Self-consistent solution of cosmological radiation-hydrodynamics and chemical ionization  

SciTech Connect (OSTI)

We consider a PDE system comprising compressible hydrodynamics, flux-limited diffusion radiation transport and chemical ionization kinetics in a cosmologically-expanding universe. Under an operator-split framework, the cosmological hydrodynamics equations are solved through the piecewise parabolic method, as implemented in the Enzo community hydrodynamics code. The remainder of the model, including radiation transport, chemical ionization kinetics, and gas energy feedback, form a stiff coupled PDE system, which we solve using a fully-implicit inexact Newton approach, and which forms the crux of this paper. The inner linear Newton systems are solved using a Schur complement formulation, and employ a multigrid-preconditioned conjugate gradient solver for the inner Schur systems. We describe this approach and provide results on a suite of test problems, demonstrating its accuracy, robustness, and scalability to very large problems.

Reynolds, Daniel R. [Mathematics, Southern Methodist University, Dallas, TX 75275-0156 (United States)], E-mail: reynolds@smu.edu; Hayes, John C. [Lawrence Livermore National Lab, P.O. Box 808, L-551, Livermore, CA 94551 (United States)], E-mail: jchayes@llnl.gov; Paschos, Pascal [Ctr. for Astrophysics and Space Sciences, U.C. San Diego, La Jolla, CA 92093 (United States)], E-mail: ppaschos@minbari.ucsd.edu; Norman, Michael L. [Ctr. for Astrophysics and Space Sciences, U.C. San Diego, La Jolla, CA 92093 (United States); Physics Department, U.C. San Diego, La Jolla, CA 92093 (United States)], E-mail: mlnorman@ucsd.edu

2009-10-01T23:59:59.000Z

449

Postcollisional decay in Ne multiple ionization by H{sub 2}{sup +} ions in breakup collisions  

SciTech Connect (OSTI)

We measured the Ne{sup q+} charge-state yield distribution for Ne atoms multiply ionized by 1-MeV/amu H{sub 2}{sup +}, in coincidence with the final state of the projectile, for both breakup and nonbreakup channels. Measurements with 1-MeV H{sup +} projectiles were also performed. While the H{sub 2}{sup +} nonbreakup channel produces results similar to equal-velocity proton or electron projectiles, the breakup channels lead to a charge-state yield distribution very close to the known Ne 2s{sup -1} postcollisional decay distribution, measured through photoionization [T. A. Carlson, W. E. Hunt, and M. O. Krause, Phys. Rev. 151, 41 (1966)]. This behavior suggests that, in the breakup channels, contributions to multiple ionization from mechanisms that are usually considered to be dominant in ion-atom collisions are less important than the postcollisional decay.

Sant'Anna, M.M. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro 21941-972 (Brazil); Luna, H.; Cavalcanti, E.G.; Sigaud, G. M.; Montenegro, E. C. [Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, Caixa Postal 38071, Rio de Janeiro 22452-970 (Brazil); Santos, A.C.F. [Department of Physics, University of Missouri-Rolla, Rolla, Missouri 65401 (United States); McGrath, C.; Shah, M.B. [Department of Pure and Applied Physics, The Queen's University of Belfast, Belfast BT7 1NN, Northern Ireland (United Kingdom)

2003-10-01T23:59:59.000Z

450

MICE: The International Muon Ionization Cooling Experiment: Phase Space Cooling Measurement  

SciTech Connect (OSTI)

MICE is an experimental demonstration of muon ionization cooling using a section of an ionization cooling channel and a muon beam. The muons are produced by the decay of pions from a target dipping into the ISIS proton beam at Rutherford Appleton Laboratory (RAL). The channel includes liquid-hydrogen absorbers providing transverse and longitudinal momentum loss and high-gradient radiofrequency (RF) cavities for longitudinal reacceleration, all packed into a solenoidal magnetic channel. MICE will reduce the beam transverse emittance by about 10% for muon momenta between 140 and 240 MeV/c. Time-of-flight (TOF) counters, threshold Cherenkov counters, and a calorimeter will identify background electrons and pions. Spectrometers before and after the cooling section will measure the beam transmission and input and output emittances with an absolute precision of 0.1%.

Hart, T. L. [University of Mississippi-Oxford, University, MS 38677 (United States)

2010-03-30T23:59:59.000Z

451

Characterization of the microdialysis junction interface for capillary electrophoresis/microelectrospray ionization mass spectrometry  

SciTech Connect (OSTI)

A capillary electrophoresis/electrospray ionization mass spectrometry (CE/ESI-MS) interface, based on an electric circuit across a microdialysis membrane surrounding a short capillary segment closely connected to the separation capillary terminus, is demonstrated to be sensitive, efficient, and rugged. A microspray type ionization emitter produces a stable electrospray at the low flow rates provided by CE and thus avoids both the need for a makeup liquid flow provided by liquid junction or sheath flow interfaces and the subsequent dilution and reduction in sensitivity. Reproducibility studies and comparisons with CE/UV and the CE/sheath flow interface with ESI-MS are presented. Additionally, postrun acidification via the microdialysis junction interface is demonstrated and shown to be capable of denaturing the holomyoglobin protein noncovalent complex while maintaining separation efficiency. 21 refs., 7 figs., 1 tab.

Severs, J.C.; Smith, R.D. [Pacific Northwest National Lab., Richland, WA (United States)] [Pacific Northwest National Lab., Richland, WA (United States)

1997-06-01T23:59:59.000Z

452

Improving liquid chromatography-mass spectrometry sensitivity using a subambient pressure ionization with nanoelectrospray (SPIN) interface  

SciTech Connect (OSTI)

In this work the Subambient Pressure Ionization with Nanoelectrospray (SPIN) ion source and interface which operates at ~15-30 Torr is demonstrated to be compatible with gradient reversed-phase liquid chromatography-MS applications, exemplified here with the analysis of complex samples (a protein tryptic digest and a whole cell lysate). A low liquid chromatographic flow rate (100-400 nL/min) allowed stable electrospray to be established while avoiding electrical breakdown. Efforts to increase the operating pressure of the SPIN source relative to previously reported designs prevented solvent freezing and enhanced charged cluster/droplet desolvation. A 5-12-fold improvement in sensitivity relative to a conventional atmospheric pressure nanoelectrospray ionization (ESI) source was obtained for detected peptides.

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

2011-04-22T23:59:59.000Z

453

Charge-distribution effect of imaging molecular structure by high-order above-threshold ionization  

SciTech Connect (OSTI)

Using a triatomic molecular model, we show that the interference pattern in the high-order above-threshold ionization (HATI) spectrum depends dramatically on the charge distribution of the molecular ion. Therefore the charge distribution can be considered a crucial factor for imaging a molecular geometric structure. Based on this study, a general destructive interference formula for each above-threshold ionization channel is obtained for a polyatomic molecule concerning the positions and charge values of each nuclei. Comparisons are made for the HATI spectra of CO{sub 2}, O{sub 2}, NO{sub 2}, and N{sub 2}. These results may shed light on imaging complex molecular structure by the HATI spectrum.

Wang Bingbing; Fu Panming [Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Guo Yingchun [Department of Physics, State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China); Zhang Bin; Zhao Zengxiu [Department of Physics, National University of Defense Technology, Changsha 410073 (China); Yan Zongchao [Department of Physics, University of New Brunswick, Fredericton, New Brunswick E3B 5A3 (Canada)

2010-10-15T23:59:59.000Z

454

X-ray powerful diagnostics for highly-ionized plasmas: He-like ions  

E-Print Network [OSTI]

The calculations of the ratios of the Helium-like ion X-ray lines from C V to Si XIII are revisited in order to apply the results to density, temperature and ionization process diagnostics of data from high-resolution spectroscopy of the new generation of X-ray satellites: Chandra and XMM-Newton. Comparing to earlier computations, Porquet & Dubau (2000), the best experimental values are used for radiative transition probabilities. The influence of an external radiation field (photo-excitation), the contribution from unresolved dielectronic satellite lines and the optical depth are taken into account. These diagnostics could be applied to collision-dominated plasmas (e.g., stellar coronae), photo-ionized plasmas (e.g., ``Warm Absorber'' in AGNs), and transient plasmas (e.g., SNRs).

D. Porquet; R. Mewe; J. S. Kaastra; J. Dubau; A. J. J. Raassen

2002-04-08T23:59:59.000Z

455

Neutron and gamma detector using an ionization chamber with an integrated body and moderator  

DOE Patents [OSTI]

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 ionization chamber, into the center of which an anode extends from the plastic lid. A working gas is disposed within the ionization chamber and a high biasing voltage is connected to the cathode. Processing electronics are coupled to the anode and process current pulses which are converted into Gaussian pulses, which are either counted as neutrons or integrated as gammas, in response to whether pulse amplitude crosses a neutron threshold. The detector according to the invention may be readily fabricated into single or multilayer detector arrays.

Ianakiev, Kiril D.; Swinhoe, Martyn T.; Lestone, John Paul

2006-07-18T23:59:59.000Z

456

Shotgun Approach for Quantitative Imaging of Phospholipids Using Nanospray Desorption Electrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

Mass spectrometry imaging (MSI) has been extensively used for determining spatial distributions of molecules in biological samples, and there is increasing interest in using MSI for quantification. Nanospray desorption electrospray ionization, or nano-DESI, is an ambient MSI technique where a solvent is used for localized extraction of molecules followed by nanoelectrospray ionization. Doping the nano-DESI solvent with carefully selected standards enables online quantification during MSI experiments. In this proof-of-principle study, we demonstrate this quantification approach can be extended to provide shotgun-like quantification of phospholipids in thin brain tissue sections. Specifically, two phosphatidylcholine (PC) standards were added to the nano-DESI solvent for simultaneous imaging and quantification of 22 PC species observed in nano-DESI MSI. Furthermore, by combining the quantitative data obtained in the individual pixels, we demonstrate quantification of these PC species in seven different regions of a rat brain tissue section.

Lanekoff, Ingela T.; Thomas, Mathew; Laskin, Julia

2014-02-04T23:59:59.000Z

457

Technical specifications manual for the MARK-1 pulsed ionizing radiation detection system. Volume 1  

SciTech Connect (OSTI)

The MARK-1 detection system was developed by the Idaho National Engineering Laboratory for the US Department of Energy Office of Arms Control and Nonproliferation. The completely portable system was designed for the detection and analysis of intense photon emissions from pulsed ionizing radiation sources. This manual presents the technical design specifications for the MARK-1 detection system and was written primarily to assist the support or service technician in the service, calibration, and repair of the system. The manual presents the general detection system theory, the MARK-1 component design specifications, the acquisition and control software, the data processing sequence, and the system calibration procedure. A second manual entitled: Volume 2: Operations Manual for the MARK-1 Pulsed Ionizing Radiation Detection System (USDOE Report WINCO-1108, September 1992) provides a general operational description of the MARK-1 detection system. The Operations Manual was written primarily to assist the field operator in system operations and analysis of the data.

Lawrence, R.S.; Harker, Y.D.; Jones, J.L.; Hoggan, J.M.

1993-03-01T23:59:59.000Z

458

Renormalization shielding and eikonal analysis on the atomic collision in dense partially ionized hydrogen plasmas  

SciTech Connect (OSTI)

The renormalization plasma screening effects on the electron-ion collision are investigated in dense partially ionized hydrogen plasmas. The Hamilton-Jacobi and eikonal methods with the effective interaction potential are employed to obtain the eikonal scattering phase shift and eikonal cross section for the electron-ion collision. It is found that the influence of renormalization screening strongly suppresses the eikonal scattering phase shift as well as the eikonal cross section, especially, for small impact parameter regions. In addition, the renormalization screening effect reduces the total eikonal cross section in all energy domains. The variation of the renormalization effects on the electron-ion collision in dense partially ionized hydrogen plasmas is also discussed.

Kim, Sung Soo [Department of Applied Mathematics, Hanyang University, Ansan, Kyunggi-Do 426-791 (Korea, Republic of)] [Department of Applied Mathematics, Hanyang University, Ansan, Kyunggi-Do 426-791 (Korea, Republic of); Jung, Young-Dae [Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 426-791 (Korea, Republic of) [Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 426-791 (Korea, Republic of); Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180-3590 (United States)

2013-12-15T23:59:59.000Z

459

Solar irradiance changes and photobiological effects at Earth's surface following astrophysical ionizing radiation events  

E-Print Network [OSTI]

Astrophysical ionizing radiation events have been recognized as a potential threat to life on Earth, primarily through depletion of stratospheric ozone and subsequent increase in surface-level solar ultraviolet radiation. Simulations of the atmospheric effects of a variety of events (such as supernovae, gamma-ray bursts, and solar proton events) have been previously published, along with estimates of biological damage at Earth's surface. In this work, we employed the TUV radiative transfer model to expand and improve calculations of surface-level irradiance and biological impacts following an ionizing radiation event. We considered changes in surface-level UVB, UVA, and photosynthetically active radiation (visible light) for clear-sky conditions and fixed aerosol parameter values. We also considered a wide range of biological effects on organisms ranging from humans to phytoplankton. We found that past work overestimated UVB irradiance, but that relative estimates for increase in exposure to DNA damaging radi...

Thomas, Brian C; Snyder, Brock R

2015-01-01T23:59:59.000Z

460

Elemental and isotopic analysis of inorganic salts by laser desorption ionization mass spectrometry  

SciTech Connect (OSTI)

Laser desorption ionization mass spectrometry is applied for the analysis of elements as well as their isotopic composition in different inorganic salts. At very low laser energies the inorganic ions are desorbed and ionized from the thin layer of the sample surface. The naturally occurring isotopes of alkali and silver ions are resolved using time of flight mass spectrometer. Further increase in laser energy shows the appearance of Al, Cr, and Fe ions in the mass spectra. This indicates the penetration laser beam beyond the sample surface leading to the ablation of sample target at higher energies. The simultaneous appearance of atomic ions from the sample target at relatively higher laser energies hampers the unambiguous identification of amino acid residues from the biomolecular ions in MALDI-MS.

Jayasekharan, T.; Sahoo, N. K. [Applied Spectroscopy Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2013-02-05T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" from the National Library of EnergyBeta (NLEBeta).
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461

Competing decay-channel fluorescence, dissociation, and ionization in superexcited levels of H{sub 2}  

SciTech Connect (OSTI)

The absolute cross sections for the competing decay-channel fluorescence, dissociation, and ionization of photoexcited long-lived superexcited H{sub 2} molecular levels have been measured from the ionization threshold of H{sub 2} up to the H(1s) + H(n=3) dissociation limit. The total and partial natural widths of these levels have been determined. Good agreement is found with first principles calculations carried out with the multichannel quantum defect theory for excited levels of {sup 1{Pi}}{sub u}{sup -} symmetry, which represent 70% of the levels studied experimentally. The calculations reproduce the balance between the competing decay processes as well as its substantial evolution from level to level.

Glass-Maujean, M. [Laboratoire de Physique Moleculaire pour l'Atmosphere et l'Astrophysique, Universite Pierre et Marie Curie, 4 place Jussieu, F-75252 Paris Cedex 5 (France); Jungen, Ch. [Laboratoire Aime Cotton, Centre National de la Recherche Scientifique, Batiment 505, Universite de Paris-Sud, F-91405 Orsay (France); Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Reichardt, G.; Balzer, A. [BESSY II, Albert-Einstein-Strasse 15, D-12489 Berlin (Germany); Schmoranzer, H. [Fachbereich Physik, Technische Universitaet Kaiserslautern, D-67653 Kaiserslautern (Germany); Ehresmann, A.; Haar, I.; Reiss, P. [Institute of Physics and Interdisciplinary Nanostructure Science and Technology, Heinrich-Plett-Strasse 40, Universitaet Kassel, D-34132 Kassel (Germany)

2010-12-15T23:59:59.000Z

462

Search for Pair Production of Strongly Interacting Particles Decaying to Pairs of Jets in pp? Collisions at ?s=1.96 TeV  

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

We present a search for the pair production of a narrow nonstandard-model strongly interacting particle that decays to a pair of quarks or gluons, leading to a final state with four hadronic jets. We consider both nonresonant production via an intermediate gluon as well as resonant production via a distinct nonstandard-model intermediate strongly interacting particle. We use data collected by the CDF experiment in proton-antiproton collisions at ?s=1.96 TeV corresponding to an integrated luminosity of 6.6 fb?¹. We find the data to be consistent with nonresonant production. We report limits on ?(pp??jjjj) as a function of the masses of the hypothetical intermediate particles. Upper limits on the production cross sections for nonstandard-model particles in several resonant and nonresonant processes are also derived.

Aaltonen, T.; Albin, E.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Bae, T.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartos, P.; Bauce, M.; Bedeschi, F.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Bland, K. R.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brigliadori, L.; Bromberg, C.; Brucken, E.; Budagov, J.; Budd, H. S.; Burkett, K.; Busetto, G.; Bussey, P.; Butti, P.; Buzatu, A.; Calamba, A.; Camarda, S.; Campanelli, M.; Canelli, F.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Cho, K.; Chokheli, D.; Ciocci, M. A.; Clark, A.; Clarke, C.; Convery, M. E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C. A.; Cox, D. J.; Cremonesi, M.; Cruz, D.; Cuevas, J.; Culbertson, R.; d’Ascenzo, N.; Datta, M.; De Barbaro, P.; Demortier, L.; Deninno, M.; Devoto, F.; d’Errico, M.; Di Canto, A.; Di Ruzza, B.; Dittmann, J. R.; D’Onofrio, M.; Donati, S.; Dorigo, M.; Driutti, A.; Ebina, K.; Edgar, R.; Elagin, A.; Erbacher, R.; Errede, S.; Esham, B.; Eusebi, R.; Farrington, S.; Fernández Ramos, J. P.; Field, R.; Flanagan, G.; Forrest, R.; Franklin, M.; Freeman, J. C.; Frisch, H.; Funakoshi, Y.; Garfinkel, A. F.; Garosi, P.; Gerberich, H.; Gerchtein, E.; Giagu, S.; Giakoumopoulou, V.; Gibson, K.; Ginsburg, C. M.; Giokaris, N.; Giromini, P.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldin, D.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González López, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gramellini, E.; Grinstein, S.; Grosso-Pilcher, C.; Group, R. C.; Guimaraes da Costa, J.; Hahn, S. R.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, M.; Harr, R. F.; Harrington-Taber, T.; Hatakeyama, K.; Hays, C.; Heinrich, J.; Herndon, M.; Hocker, A.; Hong, Z.; Hopkins, W.; Hou, S.; Hughes, R. E.; Husemann, U.; Hussein, M.; Huston, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E. J.; Jindariani, S.; Jones, M.; Joo, K. K.; Jun, S. Y.; Junk, T. R.; Kambeitz, M.; Kamon, T.; Karchin, P. E.; Kasmi, A.; Kato, Y.; Ketchum, W.; Keung, J.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, J. E.; Kim, M. J.; Kim, S. B.; Kim, S. H.; Kim, Y. K.; Kim, Y. J.; Kimura, N.; Kirby, M.; Knoepfel, K.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Kruse, M.; Kuhr, T.; Kurata, M.; Laasanen, A. T.; Lammel, S.; Lancaster, M.; Lannon, K.; Latino, G.; Lee, H. S.; Lee, J. S.; Leo, S.; Leone, S.; Lewis, J. D.; Limosani, A.; Lipeles, E.; Liu, H.; Liu, Q.; Liu, T.; Lockwitz, S.; Loginov, A.; Lucchesi, D.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; Madrak, R.; Maestro, P.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Margaroli, F.; Marino, P.; Martínez, M.; Matera, K.; Mattson, M. E.; Mazzacane, A.; Mazzanti, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Mesropian, C.; Miao, T.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Moon, C. S.; Moore, R.; Morello, M. J.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nakano, I.; Napier, A.; Nett, J.; Neu, C.; Nigmanov, T.; Nodulman, L.; Noh, S. Y.; Norniella, O.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Ortolan, L.; Pagliarone, C.; Palencia, E.; Palni, P.; Papadimitriou, V.; Parker, W.; Pauletta, G.; Paulini, M.; Paus, C.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pondrom, L.; Poprocki, S.; Potamianos, K.; Prokoshin, F.; Pranko, A.; Ptohos, F.; Punzi, G.; Ranjan, N.; Redondo Fernández, I.; Renton, P.; Rescigno, M.; Riddick, T.; Rimondi, F.; Ristori, L.; Robson, A.; Rodriguez, T.; Rolli, S.; Ronzani, M.; Roser, R.; Rosner, J. L.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Safonov, A.; Sakumoto, W. K.; Sakurai, Y.; Santi, L.; Sato, K.; Saveliev, V.; Savoy-Navarro, A.; Schlabach, P.; Schmidt, E. E.; Schwarz, T.; Scodellaro, L.; Scuri, F.; Seidel, S.; Seiya, Y.; Semenov, A.; Sforza, F.; Shalhout, S. Z.; Shears, T.; Shepard, P. F.; Shimojima, M.; Shochet, M.; Shreyber-Tecker, I.; Simonenko, A.; Sinervo, P.; Sliwa, K.; Smith, J. R.; Snider, F. D.; Sorin, V.; Song, H.; Stancari, M.; Denis, R. St.; Stelzer, B.; Stelzer-Chilton, O.; Stentz, D.; Strologas, J.; Sudo, Y.; Sukhanov, A.; Suslov, I.; Takemasa, K.; Takeuchi, Y.; Tang, J.; Tecchio, M.; Teng, P. K.; Thom, J.; Thomson, E.; Thukral, V.; Toback, D.; Tokar, S.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.

2013-07-01T23:59:59.000Z

463

Comparison of Three Cre-LoxP Based Paired-End Library Construction Methods  

SciTech Connect (OSTI)

Paired-end library sequencing has been proven useful in scaffold construction during de novo whole genome shotgun assembly. The ability of generating mate pairs with > 8 Kb insert sizes is especially important for genomes containing long repeats. To make mate paired libraries for next generation sequencing, DNA fragments need to be circularized to bring the ends together. There are several methods that can be used for DNA circulation, namely ligation, hybridization and Cre-LoxP recombination. With higher circularization efficiency with large insert DNA fragments, Cre-LoxP recombination method generally has been used for constructing >8 kb insert size paired-end libraries. Second fragmentation step is also crucial for maintaining high library complexity and uniform genome coverage. Here we will describe the following three fragmentation methods: restriction enzyme digestion, random shearing and nick translation. We will present the comparison results for these three methods. Our data showed that all three methods are able to generate paired-end libraries with greater than 20 kb insert. Advantages and disadvantages of these three methods will be discussed as well.

Peng, Ze; Nath, Nandita; Tritt, Andrew; Liang, Shoudan; Han, James; Pennacchio, Len; Chen, Feng

2013-03-26T23:59:59.000Z

464

Spheroidal close-coupling scheme to describe ionization processes in one-electron diatomic systems  

SciTech Connect (OSTI)

We propose a molecular close-coupling expansion in terms of prolate spheroidal wave functions confined in an ellipsoidal box. We first implement the method for ionization of H{sub 2}{sup +} molecular ions, by linearly polarized strong and short laser pulses, in the nonperturbative regime and within the (fixed nuclei) Born-Oppenheimer approximation. We further analyze the adequacy of the method to reproduce both the bound and the continuum nonadiabatic processes in ion-atom collisions.

Pons, B. [Centre Lasers Intenses et Applications, UMR 5107 du CNRS, Universite de Bordeaux-I, 351 Cours de la Liberation, F-33405 Talence (France)

2003-04-01T23:59:59.000Z

465

Low pressure electrospray ionization system and process for effective transmission of ions  

DOE Patents [OSTI]

A system and method are disclosed that provide up to complete transmission of ions between coupled stages with low effective ion losses. A novel "interfaceless" electrospray ionization system is further described that operates the electrospray at a reduced pressure such that standard electrospray sample solutions can be directly sprayed into an electrodynamic ion funnel which provides ion focusing and transmission of ions into a mass analyzer.

Tang, Keqi (Richland, WA); Page, Jason S. (Kennewick, WA); Kelly, Ryan T. (Wet Richland, WA); Smith, Richard D. (Richland, WA)

2010-03-02T23:59:59.000Z

466

Low pressure electrospray ionization system and process for effective transmission of ions  

DOE Patents [OSTI]

Systems and methods that provide up to complete transmission of ions between coupled stages with low effective ion losses. An "interfaceless" electrospray ionization system is further described that operates an electrospray at a reduced pressure such that standard electrospray sample solutions can be directly sprayed into an electrodynamic ion funnel which provides ion focusing and transmission of ions into a mass analyzer. Furthermore, chambers maintained at different pressures can allow for more optimal operating conditions for an electrospray emitter and an ion guide.

Tang, Keqi (Richland, WA); Page, Jason S (Kennewick, WA); Kelly, Ryan T (West Richland, WA); Smith, Richard D (Richland, WA)

2012-05-08T23:59:59.000Z

467

Effects of ionizing radiation on the response of certain photosensitive seeds to red light  

E-Print Network [OSTI]

and molecular oxygen. Studies of phosphate metabolism (Surrey and Gordon, 1962) and phosphorylation (Gordon and Surrey, 1961) indicate that energy transfer through phosphate esterification plays an important role and may be the key enzymatic reaction in red... spectrum promoting the germination of light-sensitive lettuce seed. Smithsonian Inst. Pubis. Misc. Collections 96: 1-8 ~ 11. Gordon, S. A. , and K. Surrey. 1961. Phosphorylation and red-spectrum photomorphogenesis. ~n Effects of ionizing radiations...

Richardson, Billy

2012-06-07T23:59:59.000Z

468

THE KINEMATICS AND IONIZATION OF NUCLEAR GAS CLOUDS IN CENTAURUS A  

SciTech Connect (OSTI)

Neumayer et al. established the existence of a blueshifted cloud in the core of Centaurus A, within a few parsecs of the nucleus and close to the radio jet. We propose that the cloud has been impacted by the jet, and that it is in the foreground of the jet, accounting for its blueshifted emission on the southern side of the nucleus. We consider both shock excitation and photoionization models for the excitation of the cloud. Shock models do not account for the [Si VI] and [Ca VIII] emission line fluxes. However, X-ray observations indicate a source of ionizing photons in the core of Centaurus A; photoionization by the inferred flux incident on the cloud can account for the fluxes in these lines relative to Brackett-{gamma}. The power-law slope of the ionizing continuum matches that inferred from synchrotron models of the X-rays. The logarithm of the ionization parameter is -1.9, typical of that in Seyfert galaxies and consistent with the value proposed for dusty ionized plasmas. The model cloud density depends upon the Lorentz factor of the blazar and the inclination of our line of sight to the jet axis. For acute inclinations, the inferred density is consistent with expected cloud densities. However, for moderate inclinations of the jet to the line of sight, high Lorentz factors imply cloud densities in excess of 10{sup 5} cm{sup -3} and very low filling factors, suggesting that models of the gamma-ray emission should incorporate jet Lorentz factors {approx}< 5.

Bicknell, Geoffrey V.; Sutherland, Ralph S. [Research School of Astronomy and Astrophysics, Australian National University, Mt. Stromlo Observatory, Cotter Rd., Weston, ACT 2611 (Australia)] [Research School of Astronomy and Astrophysics, Australian National University, Mt. Stromlo Observatory, Cotter Rd., Weston, ACT 2611 (Australia); Neumayer, Nadine, E-mail: Geoff.Bicknell@anu.edu.au, E-mail: Ralph.Sutherland@anu.edu.au, E-mail: nadine.neumayer@universe-cluster.de [European Southern Observatory, Karl-Schwarzschild Strasse 2, D-85748 Garching (Germany)] [European Southern Observatory, Karl-Schwarzschild Strasse 2, D-85748 Garching (Germany)

2013-03-20T23:59:59.000Z

469

Electron impact and chemical ionization mass spectral analysis of a volatile uranyl derivative  

SciTech Connect (OSTI)

Quadrupole mass spectral analysis of the volatile uranium ligand complex bis (1,1,1,5,5,5-hexafluoro-2,4-pentanedionato) dioxouranium-di-n-butyl sulfoxide is described utilizing electron impact (EI) and methane chemical ionization (CI) ion sources. All major ions are tentatively identified and the potential usefulness of this complex for determining uranium isotope /sup 235/U//sup 238/U abundance is demonstrated.

Reutter, D.J.; Hardy, D.R.

1981-01-01T23:59:59.000Z

470

CHEMILUMINESCENT CHEMI-IONIZATION: Ar* + Ca AND THE CaAr+ EMISSION SPECTRUM  

SciTech Connect (OSTI)

A flowing afterglow chemiluminescence apparatus has been used to analyze visible fluorescence in the Ar* ({sup 3}P{sub 2}{sup o}) + Ca ({sup 1}S{sub 0}) reaction. The rate constants for production of Ca{sup +} ({sup 2}P{sub 3/2}{sup o}) and Ca{sup +} ({sup 2}P{sub 1/2}{sup o}) were measured to be 1.6 x 10{sup -10} cm{sup 3}-molecule{sup -1} sec{sup -1} and 3.2 x 10{sup -11} cm{sup 3} molecule{sup -1} sec{sup -1}, respectively. These results demonstrate a transfer of the total electronic angular momentum polarization in Ar* tothe excited ion levels. The molecular band spectrum of the associative ionization product CaAr{sup +} (A{sup 2}{Pi}) was observed. Molecular fluorescence constituted 14% of the total fluorescence from all ion products. This spectrum was analyzed with a model (exp-Z4) potential, yielding, for the ground state, {Chi}{sup 2}{Sigma}{sup +}, R{sub e} = 2.8 {angstrom}, {omega}''{sub e} = 87 cm{sup -1}, and D''{sub e} = 1000 cm{sup -1}, and, for the A{sup 2}{Pi} state, R{sub e} = 2.6 {angstrom}, {omega}'{sub e} = 200 cm{sup -1}, and D'{sub e} = 4900 cm{sup -1}. The nascent internal state distribution in CaAr{sup +} is found to consist of a fairly narrow range of high vibrational levels. The analysis of spectra from chemiluminescent reaction is a well established technique for elucidating the product state distributions of elementary processes. In this paper, they use the analysis of the chemiluminescent chemi-ionization reactions between metastable argon atoms and calcium atoms to expose the dynamics of associative ionization (AI) and to measure the branching ratios for chemi-ionization into more than one product channel.

Hartman, Dennis C.; Winn, John S.

1980-09-01T23:59:59.000Z

471

Mg II Selected Absorbers: Ionization structures and a Survey of Weak Systems  

E-Print Network [OSTI]

First results from a study of high ionization absorption properties in roughly 30 Mg II absorption selected galaxies are presented. We have tested for correlations of Mg II, C IV, Si IV, N V, and O VI equivalent widths with the galaxy properties and Mg II gas kinematics. The results are suggestive of multi-phase halos with little to no global ionization gradient with impact parameter. C IV may arise in both the Mg II - Lyman alpha clouds and a high ionization "halo" traced by O VI. We also report on an unbiased survey for weak Mg II systems using HIRES/Keck spectra. At = 0.9, we find dN/dz = 1.6 +/- 0.1 for 0.02 = -0.3 +/- 0.4 measured for the sample. We suggest that weak Mg II absorbers comprise a substantial yet-to-be explored population. If weak systems select the LSB and/or dwarf galaxy population, then the weakest Mg II absorbers may provide one of the most sensitive tracers of chemical enrichment and evolution of the UV background from z = 2 to z = 0.

Christopher W. Churchill

1997-09-12T23:59:59.000Z

472

Multicomponent dynamics of coupled quantum subspaces and field-induced molecular ionizations  

SciTech Connect (OSTI)

To describe successive ionization steps of a many-electron atom or molecule driven by an ultrashort, intense laser pulse, we introduce a hierarchy of successive two-subspace Feshbach partitions of the N-electron Hilbert space, and solve the partitioned time-dependent Schrödinger equation by a short-time unitary algorithm. The partitioning scheme allows one to use different level of theory to treat the many-electron dynamics in different subspaces. We illustrate the procedure on a simple two-active-electron model molecular system subjected to a few-cycle extreme Ultra-Violet (XUV) pulse to study channel-resolved photoelectron spectra as a function of the pulse's central frequency and duration. We observe how the momentum and kinetic-energy distributions of photoelectrons accompanying the formation of the molecular cation in a given electronic state (channel) change as the XUV few-cycle pulse's width is varied, from a form characteristic of an impulsive ionization regime, corresponding to the limit of a delta-function pulse, to a form characteristic of multiphoton above-threshold ionization, often associated with continuous-wave infinitely long pulse.

Nguyen-Dang, Thanh-Tung; Viau-Trudel, Jérémy [Département de Chimie, Université Laval, Québec, Québec G1K 7P4 (Canada)] [Département de Chimie, Université Laval, Québec, Québec G1K 7P4 (Canada)

2013-12-28T23:59:59.000Z

473

High Sensitivity Combined with Extended Structural Coverage of Labile Compounds via Nanoelectrospray Ionization at Subambient Pressures  

SciTech Connect (OSTI)

Subambient pressure ionization with nanoelectrospray (SPIN) has proven to be effective in producing ions with high efficiency and transmitting them to low pressures for high sensitivity mass spectrometry (MS) analysis. Here we present evidence that not only does the SPIN source improve MS sensitivity but also allows for gentler ionization conditions. The gentleness of a conventional heated capillary electrospray ionization (ESI) source and the SPIN source was compared by the liquid chromatography mass spectrometry (LC-MS) analysis of colominic acid. Colominic acid is a mixture of sialic acid polymers of different lengths containing labile glycosidic linkages between monomer units necessitating a gentle ion source. By coupling the SPIN source with high resolution mass spectrometry and using advanced data processing tools, we demonstrate much extended coverage of sialic acid polymer chains as compared to using the conventional ESI source. Additionally we show that SPIN-LC-MS is effective in elucidating polymer features with high efficiency and high sensitivity previously unattainable by the conventional ESI-LC-MS methods. ?

Cox, Jonathan T.; Kronewitter, Scott R.; Shukla, Anil K.; Moore, Ronald J.; Smith, Richard D.; Tang, Keqi

2014-10-07T23:59:59.000Z

474

Strong-field approximation for ionization of a diatomic molecule by a strong laser field  

SciTech Connect (OSTI)

We present a theory of ionization of diatomic molecules by a strong laser field. A diatomic molecule is considered as a three-particle system, which consists of two heavy atomic (ionic) centers and an electron. After the separation of the center-of-mass coordinate, the dynamics of this system is reduced to the relative electronic and nuclear coordinates. The exact S-matrix element for ionization is presented in a form in which the laser-molecule interaction is emphasized. This form is useful for application of the molecular strong-field approximation (SFA). We introduced two forms of the molecular SFA, one with the field-free and the other with the field-dressed initial molecular bound state. We relate these two forms of our modified molecular SFA to the standard molecular SFAs, introduced previously using the length gauge and the velocity gauge. Numerical examples of the ionization rates of N{sub 2} and O{sub 2} molecules are shown and compared for all four versions of the molecular SFA and we suggest that our modified molecular SFA should be used instead of the standard molecular SFA.

Milosevic, D. B. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo, Bosnia and Herzegovina and Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin (Germany)

2006-12-15T23:59:59.000Z

475

Cross-Field Current Instabilities in Thin Ionization Layers and the Enhanced Aurora  

SciTech Connect (OSTI)

Nearly half of the time, auroral displays exhibit thin, bright layers known as \\enhanced aurora." There is a substantial body of evidence that connects these displays with thin, dense, heavy ion layers in the E-region. Based on the spectral characteristics of the enhanced layers, it is believed that they result when wave-particle interaction heats ambient electrons to energies at or just above the 17 eV ionization energy of N2. While there are several possible instabilities that could produce suprathermal electrons in thin layers, there has been no clear theoretical investigation which examines in detail how wave instabilities in the thin ionization layers could develop and produce the suprathermal electrons. We examine instabilities which would occur in thin, dense, heavy ion layers using extensive analytical analysis combined with particle simulations. We analyze a cross field current instability that is found to be strongly unstable in the heavy ion layers. Electrostatic simulations show that substantial heating of the ambient electrons occurs with energization at or above the N2 ionization energy.

Jay R. Johnson and Hideo Okuda

2008-05-20T23:59:59.000Z

476

SHORT CIRCUITS IN THERMALLY IONIZED PLASMAS: A MECHANISM FOR INTERMITTENT HEATING OF PROTOPLANETARY DISKS  

SciTech Connect (OSTI)

Many astrophysical systems of interest, including protoplanetary accretion disks, are made of turbulent magnetized gas with near-solar metallicity. Thermal ionization of alkali metals in such gas exceeds non-thermal ionization when temperatures climb above roughly 1000 K. As a result, the conductivity, proportional to the ionization fraction, gains a strong, positive dependence on temperature. In this paper, we demonstrate that this relation between the temperature and the conductivity triggers an exponential instability that acts similarly to an electrical short, where the increased conductivity concentrates the current and locally increases the Ohmic heating. This contrasts with the resistivity increase expected in an ideal magnetic reconnection region. The instability acts to focus narrow current sheets into even narrower sheets with far higher currents and temperatures. We lay out the basic principles of this behavior in this paper using protoplanetary disks as our example host system, motivated by observations of chondritic meteorites and their ancestors, dust grains in protoplanetary disks, that reveal the existence of strong, frequent heating events that this instability could explain.

Hubbard, Alexander; McNally, Colin P.; Mac Low, Mordecai-Mark, E-mail: ahubbard@amnh.org, E-mail: cmcnally@nbi.dk, E-mail: mordecai@amnh.org [Department of Astrophysics, American Museum of Natural History, 79th St. at Central Park West, New York, NY 10024-5192 (United States)

2012-12-10T23:59:59.000Z

477

The Volume Fraction of Ionized Intergalactic Gas at Redshift z=6.5  

E-Print Network [OSTI]

The observed number density of Lyman-alpha sources implies a minimum volume of the inter-galactic medium that must be ionized, in order to allow the Lyman-alpha photons to escape attenuation. We estimate this volume by assigning to each Lyman-alpha emitter the minimum Stromgren sphere that would allow half its Lyman-alpha photons to escape. This implies a lower limit to ionized gas volume fraction of 20-50% at redshift z=6.5. This is a lower limit in two ways: First, we conservatively assume that the Lyman-alpha sources seen (at a relatively bright flux limit) are the only ones present; and second, we assume the smallest Stromgren sphere volume that will allow the photons to escape. This limit is completely independent of what ionizing photon sources produced the bubbles. Deeper Lyman-alpha surveys are possible with present technology, and can strengthen these limits by detecting a higher density of Lyman-alpha galaxies.

Sangeeta Malhotra; James Rhoads

2005-11-07T23:59:59.000Z

478

Low-energy structure of above-threshold-ionization electron spectra: Role of the Coulomb threshold effect  

E-Print Network [OSTI]

Recent experimental observations of above-threshold ionization of rare gas atoms and diatomic molecules by midinfrared laser fields [C. I. Blaga et al., Nat. Phys. 5, 335 (2009); W. Quan et al., Phys. Rev. Lett. 103, 093001 ...

Telnov, Dmitry A.; Chu, Shih-I

2011-06-10T23:59:59.000Z

479

Role of two-electron processes in the excitation-ionization of lithium atoms by fast ion impact  

E-Print Network [OSTI]

We study excitation and ionization in the 1.5 MeV/amu O$^{8+}$-Li collision system, which was the subject of a recent reaction-microscope-type experiment [Fischer \\textit{et al.}, Phys. Rev. Lett. \\textbf{109}, 113202 (2012)]. Starting from an independent-electron model based on determinantal wave functions and using single-electron basis generator method and continuum distorted-wave with eikonal initial-state calculations we show that pure single ionization of a lithium $K$-shell electron is too weak a process to explain the measured single differential cross section. Rather, our analysis suggests that two-electron excitation-ionization processes occur and have to be taken into account when comparing with the data. Good agreement is obtained only if we replace the independent-electron calculation by an independent-event model for one of the excitation-ionization processes and also take a shake-off process into account.

Kirchner, T; Gulyás, L

2015-01-01T23:59:59.000Z

480

Strong-field ionization rates of linear polyenes simulated with time-dependent configuration interaction with an absorbing potential  

SciTech Connect (OSTI)

The strong field ionization rates for ethylene, trans 1,3-butadiene, and trans,trans 1,3,5-hexatriene have been calculated using time-dependent configuration interaction with single excitations and a complex absorbing potential (TDCIS-CAP). The calculations used the aug-cc-pVTZ basis set with a large set of diffuse functions (3 s, 2 p, 3 d, and 1 f) on each atom. The absorbing boundary was placed 3.5 times the van der Waals radius from each atom. The simulations employed a seven-cycle cosine squared pulse with a wavelength of 800 nm. Ionization rates were calculated for intensities ranging from 0.3 × 10{sup 14} W/cm{sup 2} to 3.5 × 10{sup 14} W/cm{sup 2}. Ionization rates along the molecular axis increased markedly with increasing conjugation length. By contrast, ionization rates perpendicular to the molecular axis were almost independent of the conjugation length.

Krause, Pascal; Schlegel, H. Bernhard [Department of Chemistry, Wayne State University, Detroit, Michigan 48202-3489 (United States)

2014-11-07T23:59:59.000Z

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481

1052 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 38, NO. 4, APRIL 2010 Ionization, Plume Properties, and Performance  

E-Print Network [OSTI]

and also to increased particle losses to chamber walls, with consequent increases in electron trans ionization, with accel- eration occurring mainly in the cylindrical region, where there is no inner wall and

482

Index pairings in presence of symmetries with applications to topological insulators  

E-Print Network [OSTI]

In a basic framework of a complex Hilbert space furnished with a complex conjugation and an involution, linear operators can be real, quaternionic, symmetric or anti-symmetric, and orthogonal projections can furthermore be symplectic. This paper investigates index pairings of projections and unitaries submitted to such symmetries. Various scenarios emerge: Noether indices can take either arbitrary integer values or only even integer values or they can vanish and then possibly have secondary $\\mathbb{Z}_2$-invariants. These general results are applied to prove index theorems for the strong invariants of topological insulators. The symmetries come from the Fermi projection ($K$-theoretic part of the pairing) and the Dirac operator ($K$-homological part of the pairing depending on the dimension of physical space).

Julian Grossmann; Hermann Schulz-Baldes

2015-04-07T23:59:59.000Z

483

Mass shift effects in nonperturbative multiphoton pair production for arbitrary polarized electric fields  

E-Print Network [OSTI]

The mass shift effects in multiphoton pair production of a nonperturbative nature for arbitrary polarized electric fields are investigated numerically by employing the real-time Dirac-Heisenberg-Wigner formalism, and theoretically by proposing an effective energy concept. It is found that the theoretical results are agreement with the numerical ones very well. It is the first time to consider the roles of the momenta of created particles and the polarizations of external fields played in the mass shift effects. These results can deepen the understanding of pair production in the nonperturbative threshold regime. Moreover, the distinct mass shift effects are observable in the forthcoming experiments and can be used as a probe to distinguish the electron-positron pair production from other background events.

Z. L. Li; D. Lu; B. F. Shen; L. B. Fu; J. Liu; B. S. Xie

2014-10-23T23:59:59.000Z

484

Long-range Cooper pair splitter with high entanglement production rate  

E-Print Network [OSTI]

Cooper pairs in the superconductor are a natural source of spin entanglement. The existing proposals of the Cooper pair splitter can only realize a low efficiency of entanglement production, and its size is constrained by the superconducting coherence length. Here we show that a long-range Cooper pair splitter can be implemented in a normal metal-superconductor-normal metal (NSN) junction by driving a supercurrent in the S. The supercurrent results in a band gap modification of the S, which significantly enhances the crossed Andreev reflection (CAR) of the NSN junction and simultaneously quenches its elastic cotunneling. Therefore, a high entanglement production rate close to its saturation value can be achieved by the inverse CAR. Interestingly, in addition to the conventional entangled electron states between opposite energy levels, novel entangled states with equal energy can also be induced in our proposal.

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

2015-01-05T23:59:59.000Z

485

A CLOSE-PAIR ANALYSIS OF DAMP MERGERS AT INTERMEDIATE REDSHIFTS  

SciTech Connect (OSTI)

We have studied the kinematics of {approx}2800 candidate close-pair galaxies at 0.1 < z < 1.2 identified from the Canada-France-Hawaii Telescope Legacy Survey fields. Spectra of these systems were obtained using spectrometers on the 6.5 m Magellan and 5 m Hale telescopes. These data allow us to constrain the rate of dry mergers at intermediate redshifts and to test the 'hot halo' model for quenching of star formation. Using virial radii estimated from the correlation between dynamical and stellar masses published by Leauthaud et al., we find that around 1/5 of our candidate pairs are likely to share a common dark matter halo (our metric for close physical association). These pairs are divided into red-red, blue-red, and blue-blue systems using the rest-frame colors classification m