National Library of Energy BETA

Sample records for ionization brems pair

  1. Exact Dirac equation calculation of ionization and pair production induced by ultrarelativistic heavy ions

    E-Print Network [OSTI]

    A. J. Baltz

    1997-01-10

    An exact solution of the time-dependent Dirac equation for ionization and pair production induced by ultrarelativistic heavy ion collisions is presented. Exact transition probabilities, equivalent to those that would be obtained in an untruncated basis coupled channels calculation, are presented. Exact bound-electron positron pair production probabilities are calculated to be mostly smaller than those calculated with the same potential in perturbation theory at impact parameters small enough for differences to occur.

  2. Changing ionization conditions in SDSS galaxies with active galactic nuclei as a function of environment from pairs to clusters

    SciTech Connect (OSTI)

    Khabiboulline, Emil T.; Steinhardt, Charles L. [California Institute of Technology, 1200 East-California Boulevard, Pasadena, CA 91125 (United States); Silverman, John D. [Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa-Shi, Chiba 277-8583 (Japan); Ellison, Sara L. [Department of Physics and Astronomy, University of Victoria, Finnerty Road, Victoria, British Columbia, V8P 1A1 (Canada); Mendel, J. Trevor [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, D-85748 Garching (Germany); Patton, David R., E-mail: ekhabibo@caltech.edu [Department of Physics and Astronomy, Trent University, 1600 West Bank Drive, Peterborough, Ontario, K9J 7B8 (Canada)

    2014-11-01

    We study how active galactic nucleus (AGN) activity changes across environments from galaxy pairs to clusters using 143,843 galaxies with z < 0.2 from the Sloan Digital Sky Survey. Using a refined technique, we apply a continuous measure of AGN activity, characteristic of the ionization state of the narrow-line emitting gas. Changes in key emission-line ratios ([N II] ?6548/H?, [O III] ?5007/H?) between different samples allow us to disentangle different environmental effects while removing contamination. We confirm that galaxy interactions enhance AGN activity. However, conditions in the central regions of clusters are inhospitable for AGN activity even if galaxies are in pairs. These results can be explained through models of gas dynamics in which pair interactions stimulate the transfer of gas to the nucleus and clusters suppress gas availability for accretion onto the central black hole.

  3. Soft ionization of thermally evaporated hypergolic ionic liquid aerosols

    E-Print Network [OSTI]

    Koh, Christine J.

    2013-01-01

    thermal energy from evaporation and the energy imparted by the ionization process.energy imparted into the isolated ion pair upon thermal vaporization and minimizes reactive processes.

  4. Atmospheric sampling glow discharge ionization source

    DOE Patents [OSTI]

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

    1989-07-18

    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.

  5. Paired t testsPaired t tests Paired (dependent) t-testPaired (dependent) t test

    E-Print Network [OSTI]

    Wolverton, Steve

    Paired t testsPaired t tests #12;Paired (dependent) t-testPaired (dependent) t test · Compares test means from matched pairsCompares test means from matched pairs or two different samples from the same individualsindividuals ­ e.g., pretest & post test scores for the same group of students Ho: d = 0 d is thedifference

  6. A surface ionization source 

    E-Print Network [OSTI]

    Buzatu, Daniel J.

    1995-01-01

    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...

  7. Alkali metal ionization detector

    DOE Patents [OSTI]

    Bauerle, James E. (Plum Borough, PA); Reed, William H. (Monroeville, PA); Berkey, Edgar (Murrysville, PA)

    1978-01-01

    Variations in the conventional filament and collector electrodes of an alkali metal ionization detector, including the substitution of helical electrode configurations for either the conventional wire filament or flat plate collector; or, the substitution of a plurality of discrete filament electrodes providing an in situ capability for transferring from an operationally defective filament electrode to a previously unused filament electrode without removing the alkali metal ionization detector from the monitored environment. In particular, the helical collector arrangement which is coaxially disposed about the filament electrode, i.e. the thermal ionizer, provides an improved collection of positive ions developed by the filament electrode. The helical filament design, on the other hand, provides the advantage of an increased surface area for ionization of alkali metal-bearing species in a monitored gas environment as well as providing a relatively strong electric field for collecting the ions at the collector electrode about which the helical filament electrode is coaxially positioned. Alternatively, both the filament and collector electrodes can be helical. Furthermore, the operation of the conventional alkali metal ionization detector as a leak detector can be simplified as to cost and complexity, by operating the detector at a reduced collector potential while maintaining the sensitivity of the alkali metal ionization detector adequate for the relatively low concentration of alkali vapor and aerosol typically encountered in leak detection applications.

  8. Plasma-assisted catalytic ionization using porous nickel plate

    SciTech Connect (OSTI)

    Oohara, W.; Maeda, T.; Higuchi, T.

    2011-09-15

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

  9. Soft ionization of thermally evaporated hypergolic ionic liquid aerosols

    SciTech Connect (OSTI)

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

    2012-03-16

    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.

  10. Soft ionization of thermally evaporated hypergolic ionic liquid aerosols

    SciTech Connect (OSTI)

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

    2011-07-19

    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.

  11. ionization: Stratified symmetrical electron emission and resonantly structured ionization continuum

    E-Print Network [OSTI]

    Kaplan, Alexander

    ionization: Stratified symmetrical electron emission and resonantly structured ionization continuum, ionization produces an approximately symmetrical, stratified photoelectron cloud. S1050-2947 99 09701-2 PACS the pulse are related simply as exp (ieQ/ ) rj 0 , where the sum is taken over all the charged particles

  12. Alkali ionization detector

    DOE Patents [OSTI]

    Hrizo, John (Monroeville, PA); Bauerle, James E. (Plum Borough, PA); Witkowski, Robert E. (West Mifflin, PA)

    1982-01-01

    A calibration filament containing a sodium-bearing compound is included in combination with the sensing filament and ion collector plate of a sodium ionization detector to permit periodic generation of sodium atoms for the in-situ calibration of the detector.

  13. Electrospray Ionization Mass Spectrometry

    SciTech Connect (OSTI)

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

    2014-06-13

    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.

  14. Optimal Pairings F. Vercauteren

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    Optimal Pairings F. Vercauteren Department of Electrical Engineering, Katholieke Universiteit pairing is completely determined by its value on one set of generators of G1, G2: let G1 = P , G2 = Q with the occasional jumps caused by fundamentally new approaches. One line of research is focused on shortening

  15. Optimal Pairings F. Vercauteren #

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    Optimal Pairings F. Vercauteren # Department of Electrical Engineering, Katholieke Universiteit. Indeed, every pairing is completely determined by its value on one set of generators of G 1 , G 2 : let G improved ef­ ficiency, interspersed with the occasional jumps caused by fundamentally new approaches. One

  16. Cooper Pairs in Insulators?!

    ScienceCinema (OSTI)

    James Valles

    2010-01-08

    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. 

  17. Brazos River Erosion Management Project (BREM) Briefing Paper

    E-Print Network [OSTI]

    US Army Corps of Engineers

    in Section 219, Water Resources Development Act of 1992, for Environmental Infrastructure Projects of historic Brazos River alluvium, extending downstream to the Gulf of Mexico. Additional scour and soil loss by Fort Bend County and private property. Additionally, further erosion will impact public infrastructure

  18. Amorphous silicon ionizing particle detectors

    DOE Patents [OSTI]

    Street, R.A.; Mendez, V.P.; Kaplan, S.N.

    1988-11-15

    Amorphous silicon ionizing particle detectors having a hydrogenated amorphous silicon (a--Si:H) thin film deposited via plasma assisted chemical vapor deposition techniques are utilized to detect the presence, position and counting of high energy ionizing particles, such as electrons, x-rays, alpha particles, beta particles and gamma radiation. 15 figs.

  19. Amorphous silicon ionizing particle detectors

    DOE Patents [OSTI]

    Street, Robert A. (Palo Alto, CA); Mendez, Victor P. (Berkeley, CA); Kaplan, Selig N. (El Cerrito, CA)

    1988-01-01

    Amorphous silicon ionizing particle detectors having a hydrogenated amorphous silicon (a--Si:H) thin film deposited via plasma assisted chemical vapor deposition techniques are utilized to detect the presence, position and counting of high energy ionizing particles, such as electrons, x-rays, alpha particles, beta particles and gamma radiation.

  20. Ionizing radiation detector

    DOE Patents [OSTI]

    Thacker, Louis H. (Knoxville, TN)

    1990-01-01

    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.

  1. High pressure xenon ionization detector

    DOE Patents [OSTI]

    Markey, J.K.

    1989-11-14

    A method is provided for detecting ionization comprising allowing particles that cause ionization to contact high pressure xenon maintained at or near its critical point and measuring the amount of ionization. An apparatus is provided for detecting ionization, the apparatus comprising a vessel containing a ionizable medium, the vessel having an inlet to allow high pressure ionizable medium to enter the vessel, a means to permit particles that cause ionization of the medium to enter the vessel, an anode, a cathode, a grid and a plurality of annular field shaping rings, the field shaping rings being electrically isolated from one another, the anode, cathode, grid and field shaping rings being electrically isolated from one another in order to form an electric field between the cathode and the anode, the electric field originating at the anode and terminating at the cathode, the grid being disposed between the cathode and the anode, the field shaping rings being disposed between the cathode and the grid, the improvement comprising the medium being xenon and the vessel being maintained at a pressure of 50 to 70 atmospheres and a temperature of 0 to 30 C. 2 figs.

  2. High pressure xenon ionization detector

    DOE Patents [OSTI]

    Markey, John K. (New Haven, CT)

    1989-01-01

    A method is provided for detecting ionization comprising allowing particles that cause ionization to contact high pressure xenon maintained at or near its critical point and measuring the amount of ionization. An apparatus is provided for detecting ionization, the apparatus comprising a vessel containing a ionizable medium, the vessel having an inlet to allow high pressure ionizable medium to enter the vessel, a means to permit particles that cause ionization of the medium to enter the vessel, an anode, a cathode, a grid and a plurality of annular field shaping rings, the field shaping rings being electrically isolated from one another, the anode, cathode, grid and field shaping rings being electrically isolated from one another in order to form an electric field between the cathode and the anode, the electric field originating at the anode and terminating at the cathode, the grid being disposed between the cathode and the anode, the field shaping rings being disposed between the cathode and the grid, the improvement comprising the medium being xenon and the vessel being maintained at a pressure of 50 to 70 atmospheres and a temperature of 0.degree. to 30.degree. C.

  3. Pulsed helium ionization detection system

    DOE Patents [OSTI]

    Ramsey, Roswitha S. (Knoxville, TN); Todd, Richard A. (Knoxville, TN)

    1987-01-01

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  4. Pulsed helium ionization detection system

    DOE Patents [OSTI]

    Ramsey, R.S.; Todd, R.A.

    1985-04-09

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  5. Optical ionization detector

    DOE Patents [OSTI]

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

    1994-01-01

    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.

  6. Optical ionization detector

    DOE Patents [OSTI]

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

    1994-03-29

    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.

  7. Field ionization from carbon nanofibers

    E-Print Network [OSTI]

    Adeoti, Bosun J

    2008-01-01

    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 ...

  8. 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...

  9. Multiprocessor switch with selective pairing

    DOE Patents [OSTI]

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

    2014-03-11

    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

  10. I. IONIZATION COOLING A. Introduction

    E-Print Network [OSTI]

    McDonald, Kirk

    I. 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 electron cooling are all too slow. Optical stochastic cooling [1], electron cooling in a plasma discharge

  11. Carbon nanotube-based field ionization vacuum

    E-Print Network [OSTI]

    Jang, Daniel, M. Eng. Massachusetts Institute of Technology

    2012-01-01

    We report the development of a novel micropump architecture that uses arrays of isolated vertical carbon nanotubes (CNT) to field ionize gas particles. The ionized gas molecules are accelerated to and implanted into a ...

  12. Sharp tridiagonal pairs

    E-Print Network [OSTI]

    Nomura, Kazumasa

    2007-01-01

    Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of $K$-linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfies the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering ${V_i}_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering ${V^*_i}_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv) there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \

  13. Nebular spectra of pair-instability supernovae

    E-Print Network [OSTI]

    Jerkstrand, A; Heger, A

    2015-01-01

    If very massive stars (M >~ 100 Msun) can form and avoid too strong mass loss during their evolution, they are predicted to explode as pair-instability supernovae (PISNe). One critical test for candidate events is whether their nucleosynthesis yields and internal ejecta structure, being revealed through nebular-phase spectra at t >~ 1 yr, match those of model predictions. Here we compute theoretical spectra based on model PISN ejecta at 1-3 years post-explosion to allow quantitative comparison with observations. The high column densities of PISNe lead to complete gamma-ray trapping for t >~ 2 years which, combined with fulfilled conditions of steady state, leads to bolometric supernova luminosities matching the 56Co decay. Most of the gamma-rays are absorbed by the deep-lying iron and silicon/sulphur layers. The ionization balance shows a predominantly neutral gas state, which leads to emission lines of Fe I, Si I, and S I. For low-mass PISNe the metal core expands slowly enough to produce a forest of distinc...

  14. Ionization probes of molecular structure and chemistry

    SciTech Connect (OSTI)

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

    1993-12-01

    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.

  15. Saha Ionization Formula and the Voids

    E-Print Network [OSTI]

    Mofazzal Azam

    2002-08-14

    The ultra-low density limit of Saha ionization formula suggests that, in this limit, matter would prefer to remain ionized.This has a very important implication for cosmic structures known as Voids.These are ultra-low density (much less than average density of matter in the Universe) regions in the galactic clusters and superclusters.The ionization formula implies that matter trapped in the Voids should be ionized.Therefore, we expect a very faint radiation glow from the Voids resulting from the motion of the charged particles.

  16. NONSMOOTH LYAPUNOV PAIRS FOR INFINITE-DIMENSIONAL ...

    E-Print Network [OSTI]

    2010-05-27

    continuous Lyapunov pairs or functions associated to first-order differential ... continuous Lyapunov pairs and functions, invariance of sets, subdifferential sets,

  17. Ionization tube simmer current circuit

    DOE Patents [OSTI]

    Steinkraus, R.F. Jr.

    1994-12-13

    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.

  18. Ionization tube simmer current circuit

    DOE Patents [OSTI]

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

    1994-01-01

    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.

  19. Organic materials and devices for detecting ionizing radiation

    DOE Patents [OSTI]

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

    2007-03-06

    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.

  20. Coulomb pairing resonances in multiple-ring aromatic molecules

    E-Print Network [OSTI]

    Huber, D L

    2015-01-01

    We present an analysis of the Coulomb pairing resonances observed in photo-double-ionization studies of CnHm aromatic molecules with multiple benzene-like rings. It is applied to naphthalene, anthracene, phenanthrene, pyrene and coronene, all of which have six-member rings, and azulene which is comprised of a five-member and a seven-member ring. There is a high energy resonance at ~ 40 eV that is found in all of the molecules cited and is associated with paired electrons localized on carbon sites on the perimeter of the molecule, each of which having two carbon sites as nearest neighbors. The low energy resonance at 10 eV, which is found only in pyrene and coronene, is attributed to the formation of paired electrons localized on arrays of interior carbon atoms that have the point symmetry of the molecule with each carbon atom having three nearest neighbors. The origin of the anomalous increase in the doubly charged to singly charged parent-ion ratio that is found above the 40 eV resonance in all of the cited ...

  1. Competitive ionization processes of anthracene excited with a...

    Office of Scientific and Technical Information (OSTI)

    the ionization mechanism of large molecules under multi-photon ionization conditions, photo-electron spectroscopic studies on anthracene have been performed with electron imaging...

  2. Tridiagonal pairs of Krawtchouk type

    E-Print Network [OSTI]

    Ito, Tatsuro

    2007-01-01

    Let $K$ denote an algebraically closed field with characteristic 0 and let $V$ denote a vector space over $K$ with finite positive dimension. Let $A,A^*$ denote a tridiagonal pair on $V$ with diameter $d$. We say that $A,A^*$ has Krawtchouk type whenever the sequence $\\lbrace d-2i\\rbrace_{i=0}^d$ is a standard ordering of the eigenvalues of $A$ and a standard ordering of the eigenvalues of $A^*$. Assume $A,A^*$ has Krawtchouk type. We show that there exists a nondegenerate symmetric bilinear form $$ on $V$ such that $= $ and $= $ for $u,v\\in V$. We show that the following tridiagonal pairs are isomorphic: (i) $A,A^*$; (ii) $-A,-A^*$; (iii) $A^*,A$; (iv) $-A^*,-A$. We give a number of related results and conjectures.

  3. (Resonance ionization spectroscopy and its applications)

    SciTech Connect (OSTI)

    Ramsey, J.M.

    1990-10-11

    The Fifth International Symposium in Resonance Ionization Spectroscopy and Its Applications was attended. The Joint Research Centre of the European Communities at Ispra, Italy was also visited. The traveler presented an invited talk, chaired a meeting session and gave an impromptu presentation on how current laser technology limits the development of commercial instrumentation based upon Resonance Ionization Spectroscopy. The conference was truely international with scientists from 19 countries and less than 1/4 from the US. The meeting also provided a health mixture of experimentalists and theoreticians. Technical developments reported included the use of electric field ionization from laser prepared Rydberg states as a way to reduce background signals and commercial development of an optical parametric oscillator for replacing pulsed dye laser. A speaker from the Soviet Union suggested their willingness to market hardware they have developed based upon the resonance ionization technique.

  4. The warm ionized medium in spiral galaxies

    E-Print Network [OSTI]

    Haffner, L M; Beckman, J E; Wood, K; Slavin, J D; Giammanco, C; Madsen, G J; Zurita, A; Reynolds, R J

    2009-01-01

    This article reviews observations and models of the diffuse ionized gas that permeates the disk and halo of our Galaxy and others. It was inspired by a series of invited talks presented during an afternoon scientific session of the 65th birthday celebration for Professor Carl Heiles held at Arecibo Observatory in August 2004. This review is in recognition of Carl's long standing interest in and advocacy for studies of the ionized as well as the neutral components of the interstellar medium.

  5. The ion pairs and superconducting bosons

    E-Print Network [OSTI]

    V. N. Minasyan

    2009-02-11

    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.

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

    E-Print Network [OSTI]

    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

    2015-05-27

    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 narrow band 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 57.3 keV and for median applied electric fields from 0 to 970 V/cm. For the ionization yields, we report measurements from 16.9 to 57.3 keV and for electric fields from 96.4 to 486 V/cm. We also report the observation of an anticorrelation between scintillation and ionization from nuclear recoils, which is similar to the anticorrelation between scintillation and ionization from electron recoils. Assuming that the energy loss partitions into excitons and ion pairs from $^{83m}$Kr internal conversion electrons is comparable to that from $^{207}$Bi conversion electrons, we obtained the numbers of excitons ($N_{ex}$) and ion pairs ($N_i$) and their ratio ($N_{ex}/N_i$) produced by nuclear recoils from 16.9 to 57.3 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.

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

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

    Cao, H.

    2015-05-26

    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 narrow band 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 also report measurements of the scintillation yields for nuclear recoils with energies from 10.3 to 57.3 keV and for median applied electric fields from 0more »to 970 V/cm. For the ionization yields, we report measurements from 16.9 to 57.3 keV and for electric fields from 96.4 to 486 V/cm. Furthermore, we report the observation of an anticorrelation between scintillation and ionization from nuclear recoils, which is similar to the anticorrelation between scintillation and ionization from electron recoils. Assuming that the energy loss partitions into excitons and ion pairs from 83mKr internal conversion electrons is comparable to that from 207Bi conversion electrons, we obtained the numbers of excitons (Nex) and ion pairs (Ni) and their ratio (Nex/Ni) produced by nuclear recoils from 16.9 to 57.3 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.« less

  8. Multiphoton ionization of large water clusters

    SciTech Connect (OSTI)

    Apicella, B.; Li, X.; Passaro, M.; Spinelli, N.; Wang, X.

    2014-05-28

    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.

  9. Pairing Correlations in halo Nuclei

    E-Print Network [OSTI]

    H. Sagawa; K. Hagino

    2007-09-10

    Paring correlations in weakly bound halo nuclei $^{6}$He and $^{11}$Li are studied by using a three-body model with a density-dependent contact interaction. We investigate the spatial structure of two-neutron wave function in a Borromean nucleus $^{11}$Li.The behavior of the neutron pair at different densities is simulated by calculating the two-neutron wave function at several distances between the core nucleus $^9$Li and the center of mass of the two neutrons. With this representation, a strong concentration of the neutron pair on the nuclear surface is quantitatively established for neutron-rich nuclei. Dipole excitations in $^{6}$He and $^{11}$Li are also studied within the same three-body model and compared with experimental data. The small open angles between the two neutrons from the core are extracted empirically by the B(E1) sum rule together with the rms mass radii, indicating the strong di-neutron correlation in the halo nuclei.

  10. Memory in Nonlinear Ionization of Transparent Solids

    SciTech Connect (OSTI)

    Rajeev, P. P.; Simova, E.; Hnatovsky, C.; Taylor, R. S.; Rayner, D. M.; Corkum, P. B.; Gertsvolf, M.; Bhardwaj, V. R.

    2006-12-22

    We demonstrate a shot-to-shot reduction in the threshold laser intensity for ionization of bulk glasses illuminated by intense femtosecond pulses. For SiO{sub 2} the threshold change serves as positive feedback reenforcing the process that produced it. This constitutes a memory in nonlinear ionization of the material. The threshold change saturates with the number of pulses incident at a given spot. Irrespective of the pulse energy, the magnitude of the saturated threshold change is constant ({approx}20%). However, the number of shots required to reach saturation does depend on the pulse energy. Recognition of a memory in ionization is vital to understand multishot optical or electrical breakdown phenomena in dielectrics.

  11. Resonance ionization spectroscopy of zirconium atoms

    SciTech Connect (OSTI)

    Page, R.H.; Dropinski, S.C.; Worden, E.F. Jr.; Stockdale, J.A.D.

    1992-05-01

    We have examined the stepwise-resonant three-photon-ionization spectrum of neutral zirconium atoms using three separately-tunable pulsed visible dye lasers. Lifetimes of even-parity levels (measured with delayed-photoionization technique) range from 10 to 100 nsec. Direct ionization cross sections appear to be less than 10{sup {minus}17} cm{sup 2}; newly-detected autoionizing levels give peak ionization cross sections (inferred from saturation fluences) up to 10{sup {minus}15} cm{sup 2}. Members of Rydberg series converging to the 315 and 1323 cm{sup {minus}1} levels of Zr{sup +} were identified. ``Clumps`` of autoionizing levels are thought to be due to Rydberg-valence mixing.

  12. Ionization energies along beryllium isoelectronic sequence

    E-Print Network [OSTI]

    Malyshev, A V; Glazov, D A; Tupitsyn, I I; Shabaev, V M; Plunien, G

    2015-01-01

    Ionization energies for the ground state of berylliumlike ions with nuclear charge numbers in the range Z=16-96 are rigorously evaluated. The calculations merge the ab initio QED treatment in the first and second orders of the perturbation theory in the fine-structure constant $\\alpha$ with the third- and higher-order electron-correlation contributions evaluated within the Breit approximation. The nuclear recoil and nuclear polarization effects are taken into account. The accuracy of the ionization energies obtained has been significantly improved in comparison with previous calculations.

  13. Deflection Effects in Inner-Shell Ionization 

    E-Print Network [OSTI]

    Swafford, G. L.; Reading, John F.; Ford, A. Lewis; Fitchard, E.

    1977-01-01

    January 1977) Recently a method of calculating inner-shell ionization has been formulated in which Hartree-Pock wave functions are employed and all terms in the Born series retained. Results have so far been presented only in the energy region where... VOLUME 16, NUMBER 3 Deflection effects in inner-shell ionization* SEPTEMBER 1977 G. L. SwafRrd, J. F. Reading, A. L Ford, and E. Fitchard Cyclotron Institute and Department of Physics, Texas A&.M University, College Station, Texas 77843 (Received 10...

  14. Galaxy pairs align with galactic filaments

    E-Print Network [OSTI]

    Tempel, Elmo

    2015-01-01

    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...

  15. Muon Cooling via Ionization Andrea Kay Forget

    E-Print Network [OSTI]

    Cinabro, David

    1 Muon Cooling via Ionization Andrea Kay Forget Department of Physics, Wayne State University decay, as a result of their short lives many of the known cooling techniques (electron, stochastic, and laser cooling) cannot be used to properly cool muons that are being used in proposed accelerators

  16. Ionization for Three Dimensional Timedependent Point Interactions

    E-Print Network [OSTI]

    is that the survival probability of the # International School of Advanced Studies SISSA/ISAS, Trieste, Italy. E models in which a non­perturbative solution exists and study the survival probability. In this paper we#ects of multiphoton ionization of excited hydrogen atoms by microwave field, with a good agreement with experiments

  17. Theory of multiphoton ionization of atoms

    SciTech Connect (OSTI)

    Szoeke, A.

    1986-03-01

    A non-perturbative approach to the theory of multiphoton ionization is reviewed. Adiabatic Floquet theory is its first approximation. It explains qualitatively the energy and angular distribution of photoelectrons. In many-electron atoms it predicts collective and inner shell excitation. 14 refs.

  18. Composite scintillators for detection of ionizing radiation

    DOE Patents [OSTI]

    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

    2010-12-28

    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.

  19. Pairing Effects in Nuclear Fusion Reaction

    E-Print Network [OSTI]

    Shuichiro Ebata; Takashi Nakatsukasa

    2013-09-29

    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.

  20. Quantum Theory for Cold Avalanche Ionization in Solids

    SciTech Connect (OSTI)

    Deng, H. X.; Zu, X. T.; Xiang, X.; Sun, K.

    2010-09-10

    A theory of photon-assisted impact ionization in solids is presented. Our theory makes a quantum description of the new impact ionization--cold avalanche ionization recently reported by P. P. Rajeev, M. Gertsvolf, P. B. Corkum, and D. M. Rayner [Phys. Rev. Lett. 102, 083001 (2009)]. The present theory agrees with the experiments and can be reduced to the traditional impact ionization expression in the absence of a laser.

  1. Pairing, pseudogap and Fermi arcs in cuprates

    SciTech Connect (OSTI)

    Kaminski, Adam; Gu, Genda; Kondo, Takeshi; Takeuchi, Tsunehiro

    2014-04-29

    We use Angle Resolved Photoemission Spectroscopy (ARPES) to study the relationship between the pseudogap, pairing and Fermi arcs in cuprates. High quality data measured over a wide range of dopings reveals a consistent picture of Fermiology and pairing in these materials. The pseudogap is due to an ordered state that competes with superconductivity rather than preformed pairs. Pairing does occur below Tpair ~ 150K and significantly above Tc, but well below T* and the doping dependence of this temperature scale is distinct from that of the pseudogap. The d-wave gap is present below Tpair, and its interplay with strong scattering creates “artificial” Fermi arcs for Tc < T < Tpair. However, above Tpair, the pseudogap exists only at the antipodal region. This leads to presence of real, gapless Fermi arcs close to the node. The length of these arcs remains constant up to T*, where the full Fermi surface is recovered. We demonstrate that these findings resolve a number of seemingly contradictory scenarios.

  2. Pairing, pseudogap and Fermi arcs in cuprates

    SciTech Connect (OSTI)

    Kaminski, Adam [Iowa State Univ., Ames, IA (United States); Gu, Genda [Brookhaven National Lab. (BNL), Upton, NY (United States); Kondo, Takeshi [The Univ. of Tokyo, Chiba (Japan); Takeuchi, Tsunehiro [Nagoya Univ., Nagoya (Japan)

    2014-10-31

    We use Angle Resolved Photoemission Spectroscopy (ARPES) to study the relationship between the pseudogap, pairing and Fermi arcs in cuprates. High quality data measured over a wide range of dopings reveals a consistent picture of Fermiology and pairing in these materials. The pseudogap is due to an ordered state that competes with superconductivity rather than preformed pairs. Pairing does occur below Tpair ~ 150K and significantly above Tc, but well below T* and the doping dependence of this temperature scale is distinct from that of the pseudogap. The d-wave gap is present below Tpair, and its interplay with strong scattering creates “artificial” Fermi arcs for Tc < T < Tpair. However, above Tpair, the pseudogap exists only at the antipodal region. This leads to presence of real, gapless Fermi arcs close to the node. The length of these arcs remains constant up to T*, where the full Fermi surface is recovered. We demonstrate that these findings resolve a number of seemingly contradictory scenarios.

  3. Modularity of Termination Using Dependency Pairs ?

    E-Print Network [OSTI]

    Ábrahám, Erika

    Modularity of Termination Using Dependency Pairs ? Thomas Arts 1 and J¨urgen Giesl 2 1 Computer@informatik.tu­darmstadt.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

  4. Shell model study of the pairing correlations

    E-Print Network [OSTI]

    J. A. Sheikh; P. A. Ganai; R. P. Singh; R. K. Bhowmick; S. Frauendorf

    2007-12-19

    A systematic study of the pairing correlations as a function of temperature and angular momentum has been performed in the sd-shell region using the spherical shell model approach. The pairing correlations have been derived for even-even, even-odd and odd-odd systems near N=Z and also for the asymmetric case of N=Z+4. The results indicate that the pairing content and the behavior of pair correlations is similar in even-even and odd-mass nuclei. For odd-odd N=Z system, angular momentum I=0 state is an isospin, t=1 neutron-proton paired configuration. Further, these t=1 correlations are shown to be dramatically reduced for the asymmetric case of N=Z+4. The shell model results obtained are qualitatively explained within a simplified degenerate model.

  5. Alloy nanoparticle synthesis using ionizing radiation

    DOE Patents [OSTI]

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

    2011-08-16

    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.

  6. Closed-loop pulsed helium ionization detector

    DOE Patents [OSTI]

    Ramsey, Roswitha S. (Knoxville, TN); Todd, Richard A. (Knoxville, TN)

    1987-01-01

    A helium ionization detector for gas chromatography is operated in a constant current, pulse-modulated mode by configuring the detector, electrometer and a high voltage pulser in a closed-loop control system. The detector current is maintained at a fixed level by varying the frequency of fixed-width, high-voltage bias pulses applied to the detector. An output signal proportional to the pulse frequency is produced which is indicative of the charge collected for a detected species.

  7. Genetic variation in resistance to ionizing radiation

    SciTech Connect (OSTI)

    Ayala, F.J.

    1989-01-01

    The very reactive superoxide anion O[sub 2] is generated during cell respiration as well as during exposure to ionizing radiation. Organisms have evolved different mechanisms to protect against the deleterious effects of reduced oxygen species. The copper-zinc superoxide dismutase is a eukaryotic cytoplasmic enzyme that protects the cell by scavenging superoxide radicals and dismutating them to hydrogen peroxide and molecular oxygen: 20[sub 2][sup [minus

  8. Orientation-dependent ionization yields from strong-field ionization of fixed-in-space linear and asymmetric top molecules

    E-Print Network [OSTI]

    Hansen, Jonas L; Nielsen, Jens H; Stapelfeldt, Henrik; Dimitrovski, Darko; Madsen, Lars Bojer

    2011-01-01

    The yield of strong-field ionization, by a linearly polarized probe pulse, is studied experimentally and theoretically, as a function of the relative orientation between the laser field and the molecule. Experimentally, carbonyl sulfide, benzonitrile and naphthalene molecules are aligned in one or three dimensions before being singly ionized by a 30 fs laser pulse centered at 800 nm. Theoretically, we address the behaviour of these three molecules. We consider the degree of alignment and orientation and model the angular dependence of the total ionization yield by molecular tunneling theory accounting for the Stark shift of the energy level of the ionizing orbital. For naphthalene and benzonitrile the orientational dependence of the ionization yield agrees well with the calculated results, in particular the observation that ionization is maximized when the probe laser is polarized along the most polarizable axis. For OCS the observation of maximum ionization yield when the probe is perpendicular to the intern...

  9. Pair creation in heavy ion channeling

    E-Print Network [OSTI]

    Nikolay A. Belov; Zoltán Harman

    2014-11-20

    Heavy ions channeling through crystals with multi-GeV kinetic energies can create electron-positron pairs. In the framework of the ion, the energy of virtual photons arising from the periodic crystal potential may exceed the threshold $2mc^2$. The repeated periodic collisions with the crystal ions yield high pair production rates. When the virtual photon frequency matches a nuclear transition in the ion, the production rate can be resonantly increased. In this two-step excitation-pair conversion scheme, the excitation rates are coherently enhanced, and they scale approximately quadratically with the number of crystal sites along the channel.

  10. Pair Creation at Large Inherent Angles

    SciTech Connect (OSTI)

    Chen, P.; Tauchi, T.; Schroeder, D.V.; /SLAC

    2007-04-25

    In the next-generation linear colliders, the low-energy e{sup +}e{sup -} pairs created during the collision of high-energy e{sup +}e{sup -} beams would cause potential deleterious background problems to the detectors. At low collider energies, the pairs are made essentially by the incoherent process, where the pair is created by the interaction of beamstrahlung photons on the individual particles in the oncoming beam. This problem was first identified by Zolotarev, et al[1]. At energies where the beamstrahlung parameter {Upsilon} lies approximately in the range 0.6 {approx}< {Upsilon} {approx}< 100, pair creation from the beamstrahlung photons is dominated by a coherent process, first noted by Chen[2]. The seriousness of this pair creation problem lies in the transverse momenta that the pair particles carry when leaving the interaction point (IP) with large angles. One source of transverse momentum is from the kick by the field of the oncoming beam which results in an outcoming angle {theta} {proportional_to} 1/{radical}x, where x is the fractional energy of the particle relative to the initial beam particle energy[2,3]. As was shown in Ref. 131, there in fact exists an energy threshold for the coherent pairs, where x{sub th} {approx}> 1/2{Upsilon}. Thus within a tolerable exiting angle, there exists an upper limit for {Upsilon} where all coherent pairs would leave the detector through the exhaust port[4]. A somewhat different analysis has been done by Schroeder[5]. In the next generation of linear colliders, as it occurs, the coherent pairs can be exponentially suppressed[2] by properly choosing the {Upsilon}({approx}< 0.6). When this is achieved, the incoherent pairs becomes dominant. Since the central issue is the transverse momentum for particles with large angles, we notice that there is another source for it. Namely, when the pair particles are created at low energies, the intrinsic angles of these pairs when produced may already be large. This issue was first studied in Ref. [1]. In this paper we reinvestigate the problem, following essentially the same equivalent photon approach, but with changes in specific details including the virtual photon spectrum. In addition, various assumptions are made more explicit. The formulas derived are then applied to the collider parameters designed by Palmer[6].

  11. Improved Side Channel Attacks on Pairing Based Cryptography

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    ], and anonymous group signatures [BS04] make use of pairings as their building blocks. The adoption of pairings that analyze the vulnerability of pairings to passive attacks as well as to active attacks [PV04, KTH+ 06, WS06, WS07, PV06]. There is a variety of pairings that can be used for PBC, e.g., the Weil pairing

  12. Leonard pairs from 24 points of view

    E-Print Network [OSTI]

    Paul Terwilliger

    2004-06-28

    Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A:V\\to V$ and $A^*:V\\to V$ that satisfy both conditions below: (i) There exists a basis for $V$ with respect to which the matrix representing $A$ is diagonal and the matrix representing $A^*$ is irreducible tridiagonal. (ii) There exists a basis for $V$ with respect to which the matrix representing $A^*$ is diagonal and the matrix representing $A$ is irreducible tridiagonal. We call such a pair a {\\it Leonard pair} on $V$. Referring to the above Leonard pair, we investigate 24 bases for $V$ on which the action of $A$ and $A^*$ takes an attractive form. With respect to each of these bases, the matrices representing $A$ and $A^*$ are either diagonal, lower bidiagonal, upper bidiagonal, or tridiagonal.

  13. Schwinger pair creation in multilayer graphene

    E-Print Network [OSTI]

    M. A. Zubkov

    2012-04-05

    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.

  14. 90 Seconds of Discovery: Frustrated Lewis Pairs

    ScienceCinema (OSTI)

    Kathmann, Shawn; Schenter, Greg; Autrey, Tom

    2014-07-21

    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.

  15. 90 Seconds of Discovery: Frustrated Lewis Pairs

    SciTech Connect (OSTI)

    Kathmann, Shawn; Schenter, Greg; Autrey, Tom

    2014-02-14

    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.

  16. Nuclear Scissors with Pairing and Continuity Equation

    E-Print Network [OSTI]

    E. B. Balbutsev; L. A. Malov; P. Schuck; M. Urban

    2008-10-29

    The coupled dynamics of the isovector and isoscalar giant quadrupole resonances and low lying modes (including scissors) are studied with the help of the Wigner Function Moments (WFM) method generalized to take into account pair correlations. Equations of motion for collective variables are derived on the basis of the Time Dependent Hartree-Fock-Bogoliubov (TDHFB) equations in the harmonic oscillator model with quadrupole-quadrupole (QQ) residual interaction and a Gaussian pairing force. Special care is taken of the continuity equation.

  17. Resonance ionization detection of combustion radicals

    SciTech Connect (OSTI)

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

    1993-12-01

    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.

  18. Waveshifters and Scintillators for Ionizing Radiation Detection

    SciTech Connect (OSTI)

    B.Baumgaugh; J.Bishop; D.Karmgard; J.Marchant; M.McKenna; R.Ruchti; M.Vigneault; L.Hernandez; C.Hurlbut

    2007-12-11

    Scintillation and waveshifter materials have been developed for the detection of ionizing radiation in an STTR program between Ludlum Measurements, Inc. and the University of Notre Dame. Several new waveshifter materials have been developed which are comparable in efficiency and faster in fluorescence decay than the standard material Y11 (K27) used in particle physics for several decades. Additionally, new scintillation materials useful for fiber tracking have been developed which have been compared to 3HF. Lastly, work was done on developing liquid scintillators and paint-on scintillators and waveshifters for high radiation environments.

  19. Nonproliferation and safeguarding via ionization detection

    SciTech Connect (OSTI)

    Koster, J.E.; Johnson, J.P.; Steadman, P.

    1995-05-01

    A significant signature of the presence of special nuclear material (SNM) is ionizing radiation. SNM naturally decays with the emission of alpha particles, gamma rays, and neutrons. Detecting and monitoring these emissions is an important capability for international safeguards. A new detection method collects the ions produced by such radiation in ambient air. Alpha particles in particular are specific to heavy nuclei but have very short range. The ions produced by an alpha, however, can be transported tens of meters to an ion detector. These new monitors are rugged, very sensitive, respond in real time, and in most cases are quite portable.

  20. Pair programming improves student retention, confidence, and program quality

    E-Print Network [OSTI]

    McDowell, C; Werner, L; Bullock, H E; Fernald, J

    2006-01-01

    Werner, L.L. Building Pair Programming Knowledge through aJ. The Impact of Pair Programming on Student Performance andto Know About Pair Programming I Learned in Kindergarten.

  1. 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

  2. Minimally invasive monitoring of cellulose degradation by desorption electrospray ionization and laser ablation electrospray ionization mass

    E-Print Network [OSTI]

    Vertes, Akos

    Minimally invasive monitoring of cellulose degradation by desorption electrospray ionization cellulose degradation products produced by accelerated aging in unsized cotton paper. Soluble extracts from and degradation rate of cellulose in aging paper has been of great concern in applications where the long term

  3. LOW IONIZATION STATE PLASMA IN CORONAL MASS EJECTIONS

    SciTech Connect (OSTI)

    Lee, Jin-Yi [Department of Astronomy and Space Science, Kyung Hee University, Yongin, Gyeonggi 446-701 (Korea, Republic of); Raymond, John C. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

    2012-10-20

    The Ultraviolet Coronagraph Spectrometer (UVCS) on board the Solar and Heliospheric Observatory often observes low ionization state coronal mass ejection (CME) plasma at ultraviolet wavelengths. The CME plasmas are often detected in O VI (3 Multiplication-Sign 10{sup 5} K), C III (8 Multiplication-Sign 10{sup 4} K), Ly{alpha}, and Ly{beta}, with the low ionization plasma confined to bright filaments or blobs that appear in small segments of the UVCS slit. On the other hand, in situ observations by the Solar Wind Ion Composition Spectrometer on board Advanced Composition Explorer (ACE) have shown mostly high ionization state plasmas in the magnetic clouds in interplanetary coronal mass ejection (ICME) events, while low ionization states are rarely seen. In this analysis, we investigate whether the low ionization state CME plasmas observed by UVCS occupy small enough fractions of the CME to be consistent with the small fraction of ACE ICMEs that show low ionization plasma, or whether the CME plasma must be further ionized after passing the UVCS slit. To do this, we determine the covering factors of low ionization state plasma for 10 CME events. We find that the low ionization state plasmas in CMEs observed by UVCS show average covering factors below 10%. This indicates that the lack of low ionization state ICME plasmas observed by the ACE results from a small probability that the spacecraft passes through a region of low ionization plasma. We also find that the low ionization state plasma covering factors in faster CMEs are smaller than in slower CMEs.

  4. Hartree-Fock-Bogoliubov solution of the pairing Hamiltonian in...

    Office of Scientific and Technical Information (OSTI)

    to pairing correlations, we show how the correlated pairs are incorporated into the HFB wave function. Thereafter, we present derivation and structure of the HFB equations within...

  5. Ionized channel generation of an intense-relativistic electron beam

    DOE Patents [OSTI]

    Frost, Charles A. (Albuquerque, NM); Leifeste, Gordon T. (Albuquerque, NM); Shope, Steven L. (Albuquerque, NM)

    1988-01-01

    A foilless intense relativistic electron beam generator uses an ionized cnel to guide electrons from a cathode passed an anode to a remote location.

  6. IONIZING RADIATION RISKS TO SATELLITE POWER SYSTEMS (SPS) WORKERS

    E-Print Network [OSTI]

    Lyman, J.T.

    2010-01-01

    of carcinogenesis at low-dose radiation. These include: theeffect of low-dose ionizing radiation. Different organs and1980). However, low doses of radiation may accelerate the

  7. Evolution of extreme resistance to ionizing radiation via genetic...

    Office of Scientific and Technical Information (OSTI)

    DOE PAGES Search Results Published Article: Evolution of extreme resistance to ionizing radiation via genetic adaptation of DNA repair Title: Evolution of extreme resistance to...

  8. Dielectric liquid ionization chambers for detecting fast neutrons

    E-Print Network [OSTI]

    Boyd, Erin M

    2008-01-01

    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 ...

  9. Fe Atomic Data for Non-equilibrium Ionization Plasmas Eriksen...

    Office of Scientific and Technical Information (OSTI)

    Fe Atomic Data for Non-equilibrium Ionization Plasmas Eriksen, Kristoffer A. Los Alamos National Laboratory; Fontes, Christopher J. Los Alamos National Laboratory; Colgan,...

  10. Pairing and specific heat in hot nuclei

    E-Print Network [OSTI]

    Danilo Gambacurta; Denis Lacroix; Nicu Sandulescu

    2013-07-15

    The thermodynamics of pairing phase-transition in nuclei is studied in the canonical ensemble and treating the pairing correlations in a finite-temperature variation after projection BCS approach (FT-VAP). Due to the restoration of particle number conservation, the pairing gap and the specific heat calculated in the FT-VAP approach vary smoothly with the temperature, indicating a gradual transition from the superfluid to the normal phase, as expected in finite systems. We have checked that the predictions of the FT-VAP approach are very accurate when compared to the results obtained by an exact diagonalization of the pairing Hamiltonian. The influence of pairing correlations on specific heat is analysed for the isotopes $^{161,162}$Dy and $^{171,172}$Yb. It is shown that the FT-VAP approach, applied with a level density provided by mean field calculations and supplemented, at high energies, by the level density of the back-shifted Fermi gas model, can approximate reasonably well the main properties of specific heat extracted from experimental data. However, the detailed shape of the calculated specific heat is rather sensitive to the assumption made for the mean field.

  11. An inverse problem for Schwinger pair production

    E-Print Network [OSTI]

    Hebenstreit, Florian

    2015-01-01

    The production of electron-positron pairs in time-dependent electric fields (Schwinger mechanism) depends non-linearly on the applied field profile. Accordingly, the resulting momentum spectrum is extremely sensitive to small variations of the field parameters. Owing to this non-linear dependence it is so far unpredictable how to choose a field configuration such that a predetermined momentum distribution is generated. We show that quantum kinetic theory along with optimal control theory can be used to approximately solve this inverse problem for Schwinger pair production. We exemplify this by studying the superposition of a small number of harmonic components resulting in predetermined signatures in the asymptotic momentum spectrum. In the long run, our results could facilitate the observation of this yet unobserved pair production mechanism in quantum electrodynamics by providing suggestions for tailored field configurations.

  12. Thermodynamics of pairing transition in hot nuclei

    E-Print Network [OSTI]

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

    2014-12-16

    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.

  13. Thermodynamics of pairing in mesoscopic systems

    E-Print Network [OSTI]

    Tony Sumaryada; Alexander Volya

    2007-06-12

    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.

  14. Thermodynamics of pairing transition in hot nuclei

    E-Print Network [OSTI]

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

    2015-10-09

    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.

  15. Isominkowskian theory of Cooper Pairs in superconductors

    SciTech Connect (OSTI)

    Animalu, A.O.E. [Univ. of Nigeria, Nsukka (Nigeria)

    1993-10-01

    Via the use of Santilli`s isominkowskian space, the author presents a relativistic extension of the author`s recent treatment of the Cooper Pair in superconductivity based on the Lie-isotopic lifting of quantum mechanics known as Hadronic Mechanics. The isominkowskian treatment reduces the solution of the eiganvalue problem for the quasiparticle energy spectrum to a geometric problem of specifying the metric of the isominkowskian space inside the pair in various models of ordinary high T{sub c} superconductors. The use of an intriguing realization of the metric due to Dirac reduces the dimensionality of the interior space to two yielding a spin mutation from 1/2 to zero inside a Cooper pair in two-band BCS and Hubbard models. 12 refs.

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

    E-Print Network [OSTI]

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

    2015-03-10

    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.

  17. Quantum Key Distribution with Qubit Pairs

    E-Print Network [OSTI]

    Mohd Asad Siddiqui; Tabish Qureshi

    2014-07-17

    We propose a new Quantum Key Distribution method in which Alice sends pairs of qubits to Bob, each in one of four possible states. Bob uses one qubit to generate a secure key and the other to generate an auxiliary key. For each pair he randomly decides which qubit to use for which key. The auxiliary key has to be added to Bob's secure key in order to match Alice's secure key. This scheme provides an additional layer of security over the standard BB84 protocol.

  18. Single top and top pair production

    E-Print Network [OSTI]

    Nikolaos Kidonakis

    2012-12-12

    I present results for single-top and top-pair production at the LHC and the Tevatron. Higher-order two-loop corrections are used to achieve NNLL resummation, which is then used to derive NNLO soft-gluon corrections. Results are presented for total cross sections, top transverse momentum distributions, and top rapidity distributions. All results are in excellent agreement with data from the LHC and the Tevatron. I also clarify the differences between various methods in top-pair production and their relation to exact NNLO results.

  19. Characterization of ionized carbenes in the gas phase Robert Flammanga,

    E-Print Network [OSTI]

    Nguyen, Minh Tho

    Characterization of ionized carbenes in the gas phase Robert Flammanga, *, Minh Tho Nguyenb , Guy yet. This review is dealing with the characterization of such ionized carbenes and related ions years or so, will be divided in (1) the identification of carbenes RTMCTMR, (2) the characterization

  20. Laser desorption lamp ionization source for ion trap mass spectrometry

    E-Print Network [OSTI]

    Zare, Richard N.

    Laser desorption lamp ionization source for ion trap mass spectrometry Qinghao Wu and Richard N. Zare* A two-step laser desorption lamp ionization source coupled to an ion trap mass spectrometer (LDLI-ITMS) has been constructed and characterized. The pulsed infrared (IR) output of an Nd:YAG laser (1064 nm

  1. Thermal Ionization Jurg Frohlich and Marco Merkli yz

    E-Print Network [OSTI]

    Thermal Ionization Jurg Frohlich #3; and Marco Merkli yz Theoretical Physics ETH- Honggerberg CH is in a thermal state corresponding to a suÃ?ciently high positive temperature, and under suitable conditions is called thermal ionization. Thus, a very dilute gas of atoms or molecules in intergalactic space

  2. Ionization Efficiency in Electric Propulsion Devices Jerry L. Ross

    E-Print Network [OSTI]

    King, Lyon B.

    impulse, (s) M atomic mass, (kg) Ps power supply output, (W) Pion power required to ionize, (W) Pkin (power losses) above and beyond those arising from the ionization potential. This paper presents exhaust kinetic power, (W) Q average particle charge number q particle charge number Vd discharge voltage

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

    SciTech Connect (OSTI)

    Chung, M.; et al.

    2013-10-01

    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.

  4. The effect of recombination radiation on the temperature and ionization state of partially ionized gas

    E-Print Network [OSTI]

    Rai?evi?, Milan; Schaye, Joop; Rahmati, Alireza

    2013-01-01

    A substantial fraction of all ionizing photons originate from radiative recombinations. However, in radiative transfer calculations this recombination radiation is often assumed to be absorbed 'on-the-spot' because for most methods the computational cost associated with the inclusion of gas elements as sources is prohibitive. We present a new, CPU and memory efficient implementation for the transport of ionizing recombination radiation in the TRAPHIC radiative transfer scheme. TRAPHIC solves the radiative transfer equation by tracing photon packets at the speed of light and in a photon-conserving manner in spatially adaptive smoothed particle hydrodynamics simulations. Our new implementation uses existing features of the TRAPHIC scheme to add recombination radiation at no additional cost in the limit in which the fraction of the simulation box filled with radiation approaches 1. We test the implementation by simulating an HII region in photoionization equilibrium and comparing to reference solutions presented...

  5. Laser plasma formation assisted by ultraviolet pre-ionization

    SciTech Connect (OSTI)

    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)

    2014-10-15

    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.

  6. Isotope effect in tunnelling ionization of neutral hydrogen molecules

    E-Print Network [OSTI]

    Wang, X; Atia-Tul-Noor, A; Hu, B T; Kielpinski, D; Sang, R T; Litvinyuk, I V

    2015-01-01

    It has been recently predicted theoretically that due to nuclear motion light and heavy hydrogen molecules exposed to strong electric field should exhibit substantially different tunneling ionization rates (O.I. Tolstikhin, H.J. Worner and T. Morishita, Phys. Rev. A 87, 041401(R) (2013) [1]). We studied that isotope effect experimentally by measuring relative ionization yields for each species in a mixed H2/D2 gas jet interacting with intense femtosecond laser pulses. In a reaction microscope apparatus we detected ionic fragments from all contributing channels (single ionization, dissociation, and sequential double ionization) and determined the ratio of total single ionization yields for H2 and D2. The measured ratio agrees quantitatively with the prediction of the generalized weak-field asymptotic theory in an apparent failure of the frozen-nuclei approximation.

  7. Cryptographic Schemes based on Elliptic Curve Pairings

    E-Print Network [OSTI]

    Paterson, Kenny

    on Elliptic Curve Pairings: Contributions to Public Key Cryptography and Key Agreement Protocols This thesis are then used to make concrete CL-PKC schemes and are also used to make other efficient key agreement protocols. It does rely on the use of a trusted authority (TA) who is in possession of a master key. In this respect

  8. Efficient Pairings and ECC for Embedded Systems

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    Efficient Pairings and ECC for Embedded Systems Thomas Unterluggauer and Erich Wenger Graz-based cryptography brought forth a wide range of protocols interesting for future embedded applications. One curve and its reusability for other elliptic-curve based crypto systems offer a great solution for every

  9. Improved Modular Termination Proofs Using Dependency Pairs

    E-Print Network [OSTI]

    Middeldorp, Aart

    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

  10. Improved Modular Termination Proofs Using Dependency Pairs

    E-Print Network [OSTI]

    Ábrahám, Erika

    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

  11. Abstract polymer models with general pair interactions

    E-Print Network [OSTI]

    Aldo Procacci

    2008-11-26

    A convergence criterion of cluster expansion is presented in the case of an abstract polymer system with general pair interactions (i.e. not necessarily hard core or repulsive). As a concrete example, the low temperature disordered phase of the BEG model with infinite range interactions, decaying polynomially as $1/r^{d+\\lambda}$ with $\\lambda>0$, is studied.

  12. Pairing, pseudogap and Fermi arcs in cuprates

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

    Kaminski, Adam; Kondo, Takeshi; Takeuchi, Tsunehiro; Gu, Genda

    2014-04-29

    We use Angle Resolved Photoemission Spectroscopy (ARPES) to study the relationship between the pseudogap, pairing and Fermi arcs in cuprates. High quality data measured over a wide range of dopings reveals a consistent picture of Fermiology and pairing in these materials. The pseudogap is due to an ordered state that competes with superconductivity rather than preformed pairs. Pairing does occur below Tpair ~ 150K and significantly above Tc, but well below T* and the doping dependence of this temperature scale is distinct from that of the pseudogap. The d-wave gap is present below Tpair, and its interplay with strong scatteringmore »creates “artificial” Fermi arcs for Tc ? T ? Tpair. However, above Tpair, the pseudogap exists only at the antipodal region. This leads to presence of real, gapless Fermi arcs close to the node. The length of these arcs remains constant up to T*, where the full Fermi surface is recovered. As a result, we demonstrate that these findings resolve a number of seemingly contradictory scenarios.« less

  13. Vacuum ultraviolet mass-analyzed threshold ionization spectroscopy of p-, m-, and o-difluorobenzenes. Ionization energies

    E-Print Network [OSTI]

    Kim, Myung Soo

    Vacuum ultraviolet mass-analyzed threshold ionization spectroscopy of p-, m-, and o been measured by vacuum ultraviolet mass-analyzed threshold ionization VUV-MATI spectroscopy. From use of monochromatic and tunable vacuum ultraviolet radia- tion which is not routinely available

  14. Vacuum-ultraviolet mass-analyzed threshold ionization spectra of iodobutane isomers: Conformer-specific ionization and ion-core

    E-Print Network [OSTI]

    Kim, Myung Soo

    Vacuum-ultraviolet mass-analyzed threshold ionization spectra of iodobutane isomers: Conformer-analyzed threshold ionization MATI spectra using coherent vacuum ultraviolet radiation have been obtained for t-photon MATI spectroscopy using a vacuum-ultraviolet VUV laser source generated by four-wave mixing in Kr gas.8

  15. Ionization Spectroscopy of a DNA Base: Vacuum-Ultraviolet Mass-Analyzed Threshold Ionization Spectroscopy of Jet-Cooled Thymine

    E-Print Network [OSTI]

    Kim, Sang Kyu

    to ionizing radiation.1-8 After the initial ionization of a nucleic acid base, the hole trapped in that base migrates along the DNA helix through hopping and/or tunneling mechanisms, resulting in various types-based molecular devices. According to the hopping mechanism, charge migration in DNA occurs through hole/electron

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

    SciTech Connect (OSTI)

    Pereira, N. R.; Weber, B. V.; Phipps, D. G.; Schumer, J. W.; Seely, J. F.; Carroll, J. J.; Vanhoy, J. R.; Slabkowska, K.; Polasik, M.

    2012-10-15

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

  17. All Paired Up with No Place to Go: Pairing, Synapsis, and DSB Formation in a Balancer Heterozygote

    E-Print Network [OSTI]

    Gong, Wei J; McKim, Kim S; Hawley, R. Scott

    2005-11-18

    period of re-pairing in meiotic prophase. This observation supports the assertion made by Roeder and Weiner et al. [4,5] that the ability of Drosophila females to form a synaptonemal complex (SC) between homologous chromo- somes in the absence of double..., it is possible that despite previous somatic pairings, pairing might still need to be re- established in female meiotic prophase immediately prior to SC formation. In other words, rather than proposing that meiotic pairings are extensions of somatic pairings...

  18. Resonance ionization laser ion sources for on-line isotope separators...

    Office of Scientific and Technical Information (OSTI)

    Resonance ionization laser ion sources for on-line isotope separators (invited) Citation Details In-Document Search Title: Resonance ionization laser ion sources for on-line...

  19. Resonant photo-ionization of Yb+ to Yb2+

    E-Print Network [OSTI]

    Simon Heugel; Martin Fischer; Vladimir Elman; Robert Maiwald; Markus Sondermann; Gerd Leuchs

    2015-12-07

    We demonstrate the controlled creation of a $\\mathrm{^{174}Yb^{2+}}$ ion by photo-ionizing $\\mathrm{^{174}Yb^+}$ with weak continuous-wave lasers at ultraviolet wavelengths. The photo-ionization is performed by resonantly exciting transitions of the $\\mathrm{^{174}Yb^+}$ ion in three steps. Starting from an ion crystal of two laser-cooled $\\mathrm{^{174}Yb^+}$ ions localized in a radio-frequency trap, the verification of the ionization process is performed by characterizing the properties of the resulting mixed-species ion-crystal. The obtained results facilitate fundamental studies of physics involving $\\mathrm{Yb^{2+}}$ ions.

  20. Ionization and scintillation of nuclear recoils in gaseous xenon

    E-Print Network [OSTI]

    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

    2014-09-09

    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.

  1. Laser stripping of hydrogen atoms by direct ionization

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

    Brunetti, E.; Becker, W.; Bryant, H. C.; Jaroszynski, D. A.; Chou, W.

    2015-05-08

    Direct ionization of hydrogen atoms by laser irradiation is investigated as a potential new scheme to generate proton beams without stripping foils. The time-dependent Schrödinger equation describing the atom-radiation interaction is numerically solved obtaining accurate ionization cross-sections for a broad range of laser wavelengths, durations and energies. Parameters are identified where the Doppler frequency up-shift of radiation colliding with relativistic particles can lead to efficient ionization over large volumes and broad bandwidths using currently available lasers.

  2. Electron Ionization Mass Spectrum of Tellurium Hexafluoride

    SciTech Connect (OSTI)

    Clark, Richard A.; McNamara, Bruce K.; Barinaga, Charles J.; Peterson, James M.; Govind, Niranjan; Andersen, Amity; Abrecht, David G.; Schwantes, Jon M.; Ballou, Nathan E.

    2015-05-18

    The first electron ionization mass spectrum of tellurium hexafluoride (TeF6) is reported. The starting material was produced by direct fluorination of Te metal or TeO2 with nitrogen trifluoride. Formation of TeF6 was confirmed through cryogenic capture of the tellurium fluorination product and analysis through Raman spectroscopy. The eight natural abundance isotopes were observed for each of the set of fragment ions: TeF5+, TeF4+ TeF3+, TeF2+, TeF1+, and Te+, Te2+. A trend in increasing abundance was observed for the even fluoride bearing ions: TeF1+ < TeF3+ < TeF5+, and a decreasing abundance was observed for the even fragment series: Te(0)+ > TeF2+ > TeF4+ > TeF6+, with the molecular ion TeF6+ not observed at all. Density functional theory based electronic structure calculations were used to calculate optimized ground state geometries of these gas phase species and their relative stabilities explain the trends in the data and the lack of observed signal for TeF6+.

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

    SciTech Connect (OSTI)

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

    2014-05-13

    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.

  4. Resonant tunneling of fluctuation Cooper pairs

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

    Galda, Alexey; Mel'nikov, A. S.; Vinokur, V. M.

    2015-02-09

    Superconducting fluctuations have proved to be an irreplaceable source of information about microscopic and macroscopic material parameters that could be inferred from the experiment. According to common wisdom, the effect of thermodynamic fluctuations in the vicinity of the superconducting transition temperature, Tc, is to round off all of the sharp corners and discontinuities, which otherwise would have been expected to occur at Tc. Here we report the current spikes due to radiation-induced resonant tunneling of fluctuation Cooper pairs between two superconductors which grow even sharper and more pronounced upon approach to Tc. This striking effect offers an unprecedented tool formore »direct measurements of fluctuation Cooper pair lifetime, which is key to our understanding of the fluctuation regime, most notably to nature of the pseudogap state in high-temperature superconductors. Our finding marks a radical departure from the conventional view of superconducting fluctuations as a blurring and rounding phenomenon.« less

  5. Multiple ionization of Ar by F{sup -} impact: Projectile-electron-loss and direct-ionization collision channels

    SciTech Connect (OSTI)

    Sant'Anna, M. M.; Zappa, F.; Santos, A. C. F.; Coelho, L. F. S.; Wolff, W.; Barros, A. L. F. de; Castro Faria, N. V. de [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cx. Postal 68528, Rio de Janeiro 21941-972 (Brazil)

    2006-08-15

    We have measured single- and multiple-target ionization cross sections for the F{sup -}+Ar collision system. Measurements of the final target and projectile charge states were performed in coincidence, separating the collision channels for single-, double-, and triple-projectile-electron loss and for direct ionization. The studied velocity region extends from v=0.46 to v=1.45 atomic units. Results are compared with existing H{sup -}+Ar data as well as with Ar multiple ionization by protons, electrons, and antiprotons. For the direct-ionization channel, ratios for multiple-to-single target ionization are similar to those found for H{sup +}+Ar collisions. For this channel multiple ionization is well described by independent single-ionization events by a frozen projectile. For the projectile-electron-loss collision channels, on the other hand, the correlation between projectile electrons and target electrons plays an important role. Our data show that the average final charge state of the target, , increases steeply with the final charge state of the projectile, while an independent-particle model (neglecting two-center electron-electron correlation) only accounts for small variations of .

  6. Vortex Bubble Formation in Pair Plasmas

    E-Print Network [OSTI]

    Berezhiani, V I; Mahajan, S M; Aleksi?, B N

    2013-01-01

    It is shown that delocalized vortex solitons in relativistic pair plasmas with small temperature asymmetries can be unstable for intermediate intensities of the background electromagnetic field. Instability leads to the generation of ever-expanding cavitating bubbles in which the electromagnetic fields are zero. The existence of such electromagnetic bubbles is demonstrated by qualitative arguments based on a hydrodynamic analogy, and by numerical solutions of the appropriate Nonlinear Schr\\"odinger equation with a saturating nonlinearity.

  7. On the pairing effects in triaxial nuclei

    SciTech Connect (OSTI)

    Oudih, M. R. [Laboratoire de Physique Théorique, Faculté de Physique,USTHB BP 32, El Alia, 16111 Bab Ezzouar, Algiers (Algeria); Fellah, M.; Allal, N. H. [Centre de Recherche Nucléaire d'Alger, 2 Bd. Frantz Fanon, BP. 399 Alger-Gare, Algiers, Algeria and Laboratoire de Physique Théorique, Faculté de Physique,USTHB BP 32, El Alia, 16111 Bab Ezzouar, Algiers (Algeria)

    2014-03-05

    Triaxial deformation effect on the pairing correlations is studied in the framework of the Skyrme Hartree-Fock-Bogoliubov theory. Quantities such as binding energy, gap parameter and particle-number fluctuation are considered in neutron-rich Mo isotopes. The results are compared with those of axially symmetric calculation and with available experimental data. The role played by the particle-number projection is outlined.

  8. Persistent Ion Pairing in Aqueous Hydrochloric Acid

    SciTech Connect (OSTI)

    Baer, Marcel D.; Fulton, John L.; Balasubramanian, Mahalingam; Schenter, Gregory K.; Mundy, Christopher J.

    2014-07-03

    For strong acids, like hydrochloric acid, the complete dissociation into an excess proton and conjugated base as well as the formation of independent solvated charged fragments is assumed. The existence of a chloride-Hyronium (Cl-H3O+) contact ion pairs even in moderate concentration hydrochloric acid (2.5 m) demonstrates that the counter ions do not behave merely as spectators. Through the use of modern extended X-ray absorption fine structure (EXAFS) measurements in conjunction with state-of-the-art density functional theory (DFT) simulations, we are able to obtain an unprecedented view into the molecular structure of medium to high concentrated electrolytes. Here we report that the Cl-H3O+ contact ion pair structure persists throughout the entire concentration range studied and that these structures differ significantly from moieties studied in micro-solvated hydrochloric acid clusters. Characterizing distinct populations of these ion pairs gives rise to a novel molecular level description of how to think about the activity of the proton that impacts our picture of the pH scale. Funding for CJM, GKS, and JLF was provided by DOE Office of Science, Office of Basic Energy Science, Division of Chemical Sciences, Geosciences, and Biosciences. Funding for MDB was provided throught the Laboratory Directed Research and Development program at Pacific Northwest National Laboratory. MB was funded through Argonne National Laboratory.

  9. A compact neutron generator using a field ionization source

    E-Print Network [OSTI]

    Persaud, Arun

    2012-01-01

    Handbook of Fast Neutron Generators Volume I (CRC Press,A compact neutron generator using a ?eld ionization sourcewell logging with neutron generators. 2 Due to the harsh en-

  10. 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...

  11. Selective enhancement of resonant multiphoton ionization with strong laser fields

    E-Print Network [OSTI]

    Li, Min; Luo, Siqiang; Zhou, Yueming; Zhang, Qingbin; Lan, Pengfei; Lu, Peixiang

    2015-01-01

    High-resolution photoelectron momentum distributions of Xe atom ionized by 800-nm linearly polarized laser fields have been traced at intensities from 1.1*1013 W/cm2 to 3.5*1013 W/cm2 using velocity-map imaging techniques. At certain laser intensities, the momentum spectrum exhibits a distinct double-ring structure for low-order above-threshold ionization, which appears to be absent at lower or higher laser intensities. By investigating intensity-resolved photoelectron energy spectrum, we find that this double-ring structure originates from resonant multiphoton ionization involving multiple Rydberg states of atoms. Varying the laser intensity, we can selectively enhance multiphoton excitation of atomic Rydberg populations. The photoelectron angular distributions of multiphoton resonance are also investigated for the low-order above threshold ionization.

  12. 22.01 Introduction to Ionizing Radiation, Fall 2003

    E-Print Network [OSTI]

    Coderre, Jeffrey A.

    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, ...

  13. The Propagation of Photons in the Dilute Ionized Gas

    E-Print Network [OSTI]

    Yijia Zheng

    2013-05-02

    The dilute ionized gas is very popular in the Universe. Usually only the Compton interactions, the "Sunyaev-Zel'dovich" effect, were considered while photons propagated in this medium. In this paper the "soft-photon process" is considered. Due to the soft photons emitted during the propagation of a photon in the dilute ionized gas, the main photon (propagating in the original direction) will be redshifted. The formula to calculate this redshift is derived.

  14. Performance studies of scintillating ceramic samples exposed to ionizing radiation

    E-Print Network [OSTI]

    Dissertori, G; Nessi-Tedaldi, F; Pauss, F; Wallny, R

    2012-01-01

    Scintillating ceramics are a promising, new development for various applications in science and industry. Their application in calorimetry for particle physics experiments is expected to involve an exposure to high levels of ionizing radiation. In this paper, changes in performance have been measured for scintillating ceramic samples of different composition after exposure to penetrating ionizing radiation up to a dose of 38 kGy.

  15. Performance studies of scintillating ceramic samples exposed to ionizing radiation

    E-Print Network [OSTI]

    G. Dissertori; D. Luckey; F. Nessi-Tedaldi; F. Pauss; R. Wallny

    2012-11-16

    Scintillating ceramics are a promising, new development for various applications in science and industry. Their application in calorimetry for particle physics experiments is expected to involve an exposure to high levels of ionizing radiation. In this paper, changes in performance have been measured for scintillating ceramic samples of different composition after exposure to penetrating ionizing radiation up to a dose of 38 kGy.

  16. ALFVEN WAVES IN A PARTIALLY IONIZED TWO-FLUID PLASMA

    SciTech Connect (OSTI)

    Soler, R.; Ballester, J. L.; Terradas, J.; Carbonell, M. E-mail: joseluis.ballester@uib.es E-mail: marc.carbonell@uib.es

    2013-04-20

    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.

  17. Search for pair production of first and second generation leptoquarks...

    Office of Scientific and Technical Information (OSTI)

    pair production of first and second generation leptoquarks in proton-proton collisions at sqrts 8 TeV Citation Details In-Document Search Title: Search for pair production...

  18. Efficient Implementation of the T Pairing Yosuke Katoh1

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    of characteristics 3. We report the performance results of implementa- tions on NVIDIA GTX 285, GTX 480, Tesla C1060, and Tesla C2050 graphics cards. We have implemented T pairing in three different ways, namely, one pairing

  19. A High Speed Pairing Coprocessor Using RNS and Lazy Reduction

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    A High Speed Pairing Coprocessor Using RNS and Lazy Reduction Gavin Xiaoxu Yao1 , Junfeng Fan2 using Residue Number System (RNS) and lazy reduction. We show that combining RNS, which are naturally pairing computation in 0.664 ms. Keywords: RNS, Moduli Selection, Hardware Implementation of Pairing, FPGA

  20. E cient Implementation of the Pairing on Mobilephones using BREW

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    E cient Implementation of the Pairing on Mobilephones using BREW Motoi Yoshitomiy, Tsuyoshi Takagiy processors on BREW achieves under 100 milliseconds using the supersingular curve over F397 . It has become e encryption, using the pairing on BREW mobilephones. Keywords: Pairing Based Cryptosystem, Mobilephone, BREW

  1. Large-scale shock-ionized and photo-ionized gas in M83: the impact of star formation

    E-Print Network [OSTI]

    Hong, Sungryong; Dopita, Michael A; Blair, William P; Whitmore, Bradley C; Balick, Bruce; Bond, Howard E; Carollo, Marcella; Disney, Michael J; Frogel, Jay A; Hall, Donald; Holtzman, Jon A; Kimble, Randy A; McCarthy, Patrick J; O'Connell, Robert W; Paresce, Francesco; Saha, Abhijit; Silk, Joseph I; Trauger, John T; Walker, Alistair R; Windhorst, Rogier A; Young, Erick T; Mutchler, Max

    2011-01-01

    We investigate the ionization structure of the nebular gas in M83 using the line diagnostic diagram, [O III](5007 \\degA)/H{\\beta} vs. [S II](6716 \\deg A+6731 \\deg A)/H{\\alpha} with the newly available narrowband images from the Wide Field Camera 3 (WFC3) of the Hubble Space Telescope (HST). We produce the diagnostic diagram on a pixel-by-pixel (0.2" x 0.2") basis and compare it with several photo- and shock-ionization models. For the photo-ionized gas, we observe a gradual increase of the log([O III]/H{\\beta}) ratios from the center to the spiral arm, consistent with the metallicity gradient, as the H II regions go from super solar abundance to roughly solar abundance from the center out. Using the diagnostic diagram, we separate the photo-ionized from the shock-ionized component of the gas. We find that the shock-ionized H{\\alpha} emission ranges from ~2% to about 15-33% of the total, depending on the separation criteria used. An interesting feature in the diagnostic diagram is an horizontal distribution aro...

  2. Schwinger Pair Production at Finite Temperature

    E-Print Network [OSTI]

    Medina, Leandro

    2015-01-01

    Thermal corrections to Schwinger pair production are potentially important in particle physics, nuclear physics and cosmology. However, the lowest-order contribution, arising at one loop, has proved difficult to calculate unambiguously. We show that this thermal correction may be calculated for charged scalars using the worldline formalism, where each term in the decay rate is associated with a worldline instanton. We calculate all finite-temperature worldline instantons, their actions and fluctuations prefactors, thus determining the complete one-loop decay rate at finite temperature. The thermal contribution to the decay rate becomes nonzero at a threshold temperature T=eE/2m, above which it dominates the zero temperature result.

  3. DWARF GALAXIES WITH IONIZING RADIATION FEEDBACK. I. ESCAPE OF IONIZING PHOTONS

    SciTech Connect (OSTI)

    Kim, Ji-hoon; Krumholz, Mark R.; Goldbaum, Nathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA (United States); Wise, John H. [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, Atlanta, GA (United States); Turk, Matthew J. [Department of Astronomy and Astrophysics, Columbia University, New York, NY (United States); Abel, Tom, E-mail: me@jihoonkim.org [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA (United States)

    2013-10-01

    We describe a new method for simulating ionizing radiation and supernova feedback in the analogs of low-redshift galactic disks. In this method, which we call star-forming molecular cloud (SFMC) particles, we use a ray-tracing technique to solve the radiative transfer equation for ultraviolet photons emitted by thousands of distinct particles on the fly. Joined with high numerical resolution of 3.8 pc, the realistic description of stellar feedback helps to self-regulate star formation. This new feedback scheme also enables us to study the escape of ionizing photons from star-forming clumps and from a galaxy, and to examine the evolving environment of star-forming gas clumps. By simulating a galactic disk in a halo of 2.3 × 10{sup 11} M{sub ?}, we find that the average escape fraction from all radiating sources on the spiral arms (excluding the central 2.5 kpc) fluctuates between 0.08% and 5.9% during a ?20 Myr period with a mean value of 1.1%. The flux of escaped photons from these sources is not strongly beamed, but manifests a large opening angle of more than 60° from the galactic pole. Further, we investigate the escape fraction per SFMC particle, f{sub esc}(i), and how it evolves as the particle ages. We discover that the average escape fraction f{sub esc} is dominated by a small number of SFMC particles with high f{sub esc}(i). On average, the escape fraction from an SFMC particle rises from 0.27% at its birth to 2.1% at the end of a particle lifetime, 6 Myr. This is because SFMC particles drift away from the dense gas clumps in which they were born, and because the gas around the star-forming clumps is dispersed by ionizing radiation and supernova feedback. The framework established in this study brings deeper insight into the physics of photon escape fraction from an individual star-forming clump and from a galactic disk.

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

    E-Print Network [OSTI]

    P. Finelli; S. Maurizio; J. W. Holt

    2014-11-27

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

  5. Predissociation of high-lying Rydberg states of molecular iodine via ion-pair states

    SciTech Connect (OSTI)

    Bogomolov, Alexandr S. [Institute of Chemical Kinetics and Combustion, Institutskaya Str. 3, Novosibirsk 630090 (Russian Federation)] [Institute of Chemical Kinetics and Combustion, Institutskaya Str. 3, Novosibirsk 630090 (Russian Federation); Grüner, Barbara; Mudrich, Marcel [Physikalisches Institut, Universität Freiburg, D-79104 Freiburg (Germany)] [Physikalisches Institut, Universität Freiburg, D-79104 Freiburg (Germany); Kochubei, Sergei A. [Institute of Semiconductor Physics, ac. Lavrent'yev ave., 13, Novosibirsk 630090 (Russian Federation)] [Institute of Semiconductor Physics, ac. Lavrent'yev ave., 13, Novosibirsk 630090 (Russian Federation); Baklanov, Alexey V. [Institute of Chemical Kinetics and Combustion, Institutskaya Str. 3, Novosibirsk 630090 (Russian Federation) [Institute of Chemical Kinetics and Combustion, Institutskaya Str. 3, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090 (Russian Federation)

    2014-03-28

    Velocity map imaging of the photofragments arising from two-photon photoexcitation of molecular iodine in the energy range 73?500–74?500 cm{sup ?1} covering the bands of high-lying gerade Rydberg states [{sup 2}?{sub 1/2}]{sub c}6d;0{sub g}{sup +} and [{sup 2}?{sub 1/2}]{sub c}6d;2{sub g} has been applied. The ion signal was dominated by the atomic fragment ion I{sup +}. Up to 5 dissociation channels yielding I{sup +} ions with different kinetic energies were observed when the I{sub 2} molecule was excited within discrete peaks of Rydberg states and their satellites in this region. One of these channels gives rise to images of I{sup +} and I{sup ?} ions with equal kinetic energy indicating predissociation of I{sub 2} via ion-pair states. The contribution of this channel was up to about 50% of the total I{sup +} signal. The four other channels correspond to predissociation via lower lying Rydberg states giving rise to excited iodine atoms providing I{sup +} ions by subsequent one-photon ionization by the same laser pulse. The ratio of these channels varied from peak to peak in the spectrum but their total ionic signal was always much higher than the signal of (2 + 1) resonance enhanced multi-photon ionization of I{sub 2}, which was previously considered to be the origin of ionic signal in this spectral range. The first-tier E0{sub g}{sup +} and D{sup ?}2{sub g} ion-pair states are concluded to be responsible for predissociation of Rydberg states [{sup 2}?{sub 1/2}]{sub c}6d;0{sub g}{sup +} and [{sup 2}?{sub 1/2}]{sub c}6d;2{sub g}, respectively. Further predissociation of these ion-pair states via lower lying Rydberg states gives rise to excited I(5s{sup 2}5p{sup 4}6s{sup 1}) atoms responsible for major part of ion signal. The isotropic angular distribution of the photofragment recoil directions observed for all channels indicates that the studied Rydberg states are long-lived compared with the rotational period of the I{sub 2} molecule.

  6. Inner-shell and double ionization potentials of aminophenol isomers.

    SciTech Connect (OSTI)

    Kryzhevoi, N. V.; Santra, R.; Cederbaum, L. S.

    2011-01-01

    A comprehensive study of single and double core ionization potentials of the aminophenol molecule is reported. The role of relaxation, correlation, relativistic, and basis set effects in these potentials is clarified. Special attention is paid to the isomer dependence of the single and double core ionization potentials. Some of them are also compared with the respective values of the phenol and aniline molecules. It is shown that the core level single ionization potentials of the para-, meta-, and ortho-aminophenol molecules differ only slightly from each other, rendering these structural isomers challenging to distinguish for conventional x-ray photoelectron spectroscopy. In contrast, the energy needed to remove two core electrons from different atoms depends noticeably on the mutual arrangement and even on the relative orientations of the hydroxyl and amine groups. Together with the electrostatic repulsion between the two core holes, relaxation effects accompanying double core ionization play a crucial role here. The pronounced sensitivity of the double ionization potentials, therefore, enables a spectroscopic characterization of the electronic structure of aminophenol isomers by means of x-ray two-photon photoelectron spectroscopy.

  7. Genetic variation in resistance to ionizing radiation. [Annual report, 1989

    SciTech Connect (OSTI)

    Ayala, F.J.

    1989-12-31

    The very reactive superoxide anion O{sub 2} is generated during cell respiration as well as during exposure to ionizing radiation. Organisms have evolved different mechanisms to protect against the deleterious effects of reduced oxygen species. The copper-zinc superoxide dismutase is a eukaryotic cytoplasmic enzyme that protects the cell by scavenging superoxide radicals and dismutating them to hydrogen peroxide and molecular oxygen: 20{sub 2}{sup {minus}} + 2H {yields} H{sub 2}O{sub 2} + O{sub 2}. SOD had been shown to protect against ionizing radiation damage to DNA, viruses, bacteria, mammalian cells, whole mice, and Drosophila. Evidence that genetic differences may affect sensitivity to ionizing radiation has been shown in Drosophila since differences have been shown to exist between strains and resistance to radiation can evolve under natural selection.

  8. Spatially resolved thermal desorption/ionization coupled with mass spectrometry

    DOE Patents [OSTI]

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

    2013-02-26

    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.

  9. Photoproduction of a ??Pair and Transversity GPDs

    E-Print Network [OSTI]

    M. El Beiyad; B. Pire; L. Szymanowski; S. Wallon

    2010-07-16

    We demonstrate that the chiral-odd transversity generalized parton distributions (GPDs) of the nucleon can be accessed through the exclusive photoproduction process gamma + N -> pi + rho + N', in the kinematics where the meson pair has a large invariant mass and the final nucleon has a small transverse momentum, provided the vector meson is produced in a transversely polarized state. We calculate perturbatively the scattering amplitude at leading order in alpha_s: We build a simple model for the dominant transversity GPD HT (x; chi; t) based on the concept of double distribution. Counting rates estimates show that the experiment looks feasible with the real photon beam characteristics expected at JLab@12 GeV, in low Q2 leptoproduction at Jlab@12 GeV and in the COMPASS experiment.

  10. Higher rank stable pairs and virtual localization

    E-Print Network [OSTI]

    Artan Sheshmani

    2015-02-08

    We introduce a higher rank analog of the Pandharipande-Thomas theory of stable pairs on a Calabi-Yau threefold $X$. More precisely, we develop a moduli theory for frozen triples given by the data $O^r(-n)\\rightarrow F$ where $F$ is a sheaf of pure dimension 1. The moduli space of such objects does not naturally determine an enumerative theory: that is, it does not naturally possess a perfect symmetric obstruction theory. Instead, we build a zero-dimensional virtual fundamental class by hand, by truncating a deformation-obstruction theory coming from the moduli of objects in the derived category of $X$. This yields the first deformation-theoretic construction of a higher-rank enumerative theory for Calabi-Yau threefolds. We calculate this enumerative theory for local $\\mathbb{P}^1$ using the Graber-Pandharipande virtual localization technique.

  11. Imaging with power controlled source pairs

    E-Print Network [OSTI]

    Bardsley, Patrick

    2015-01-01

    Scatterers in a homogeneous medium are imaged by probing the medium with two point sources of waves modulated by correlated signals and by measuring only intensities at one single receiver. For appropriately chosen source pairs, we show that full waveform array measurements can be recovered from such intensity measurements by solving a linear least squares problem. The least squares solution can be used to image with Kirchhoff migration, even if the solution is determined only up to a known one-dimensional nullspace. The same imaging strategy can be used when the medium is probed with point sources driven by correlated Gaussian processes and autocorrelations are measured at a single location. Since autocorrelations are robust to noise, this can be used for imaging when the probing wave is drowned in background noise.

  12. Method for sequencing DNA base pairs

    DOE Patents [OSTI]

    Sessler, A.M.; Dawson, J.

    1993-12-14

    The base pairs of a DNA structure are sequenced with the use of a scanning tunneling microscope (STM). The DNA structure is scanned by the STM probe tip, and, as it is being scanned, the DNA structure is separately subjected to a sequence of infrared radiation from four different sources, each source being selected to preferentially excite one of the four different bases in the DNA structure. Each particular base being scanned is subjected to such sequence of infrared radiation from the four different sources as that particular base is being scanned. The DNA structure as a whole is separately imaged for each subjection thereof to radiation from one only of each source. 6 figures.

  13. Pairing in bulk nuclear matter beyond BCS

    E-Print Network [OSTI]

    Ding, D; Dickhoff, W H; Dussan, H; Rios, A; Polls, A

    2014-01-01

    The influence of short-range correlations on the spectral distribution of neutrons is incorporated in the solution of the gap equation for the ${}^3P_2-{}^3F_2$ coupled channel in pure neutron matter. This effect is studied for different realistic interactions including one based on chiral perturbation theory. The gap in this channel vanishes at all relevant densities due to the treatment of these correlations. We also consider the effect of long-range correlations by including polarization terms in addition to the bare interaction which allow the neutrons to exchange density and spin fluctuations governed by the strength of Landau parameters allowed to have reasonable values consistent with the available literature. Preliminary results indicate that reasonable values of these parameters do not generate a gap in the ${}^3P_2-{}^3F_2$ coupled channel either for all three realistic interactions although the pairing interaction becomes slightly more attractive.

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

    SciTech Connect (OSTI)

    Isselhardt, B H

    2011-09-06

    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.

  15. A compact neutron generator using a field ionization source

    SciTech Connect (OSTI)

    Persaud, Arun; Waldmann, Ole; Kapadia, Rehan; Takei, Kuniharu; Javey, Ali; Schenkel, Thomas

    2011-10-31

    Field ionization as a means to create ions for compact and rugged neutron sources is pursued. Arrays of carbon nano-#12;bers promise the high #12;eld-enhancement factors required for efficient field ionization. We report on the fabrication of arrays of #12;field emitters with a density up to 10{sup 6} tips/cm{sup 2} and measure their performance characteristics using electron field emission. The critical issue of uniformity is discussed, as are efforts towards coating the nano-fibers to enhance their lifetime and surface properties.

  16. Numerical modeling of laser tunneling ionization in explicit particle-in-cell codes

    SciTech Connect (OSTI)

    Chen, M.; Cormier-Michel, E.; Geddes, C.G.R.; Bruhwiler, D.L.; Yu, L.L.; Esarey, E.; Schroeder, C.B.; Leemans, W.P.

    2013-03-01

    Methods for the calculation of laser tunneling ionization in explicit particle-in-cell codes used for modeling laser–plasma interactions are compared and validated against theoretical predictions. Improved accuracy is obtained by using the direct current form for the ionization rate. Multi level ionization in a single time step and energy conservation have been considered during the ionization process. The effects of grid resolution and number of macro-particles per cell are examined. Implementation of the ionization algorithm in two different particle-in-cell codes is compared for the case of ionization-based electron injection in a laser–plasma accelerator.

  17. Analysis of food pairing in regional cuisines of India

    E-Print Network [OSTI]

    Jain, Anupam; Bagler, Ganesh

    2015-01-01

    Any national cuisine is a sum total of its variety of regional cuisines, which are the cultural and historical identifiers of their respective regions. India is home to a number of regional cuisines that showcase its culinary diversity. Here, we study recipes from eight different regional cuisines of India spanning various geographies and climates. We investigate the phenomenon of food pairing which examines compatibility of two ingredients in a recipe in terms of their shared flavor compounds. Food pairing was enumerated at the level of cuisine, recipes as well as ingredient pairs by quantifying flavor sharing between pairs of ingredients. Our results indicate that each regional cuisine follows negative food pairing pattern; more the extent of flavor sharing between two ingredients, lesser their co-occurrence in that cuisine. We find that frequency of ingredient usage is central in rendering the characteristic food pairing in each of these cuisines. Spice and dairy emerged as the most significant ingredient ...

  18. Distinguishing LSP archetypes via gluino pair production at LHC13...

    Office of Scientific and Technical Information (OSTI)

    Distinguishing LSP archetypes via gluino pair production at LHC13 Citation Details In-Document Search This content will become publicly available on August 19, 2016 Title:...

  19. Theoretical overview on top pair production and single top production

    E-Print Network [OSTI]

    Stefan Weinzierl

    2012-01-19

    In this talk I will give an overview on theoretical aspects of top quark physics. The focus lies on top pair production and single top production.

  20. Large Higgs energy region in Higgs associated top pair production...

    Office of Scientific and Technical Information (OSTI)

    Large Higgs energy region in Higgs associated top pair production at the Linear Collider Citation Details In-Document Search Title: Large Higgs energy region in Higgs associated...

  1. Chromosomal "Fingerprints" of Prior Exposure to Densely Ionizing Radiation

    E-Print Network [OSTI]

    Brenner, David Jonathan

    be detected and measured long after radiation exposure. Specifically, they produce an anomalously low ratio (F doses of densely ionizing radiation, such as a particles or neutrons. Consequently, determina- tion ion- izing radiation doses is an important societal and legal issue. Thus there has been considerable

  2. SOFT LASER DESORPTION IONIZATION -MALDI, DIOS AND NANOSTRUCTURES

    E-Print Network [OSTI]

    Vertes, Akos

    Chapter 20 SOFT LASER DESORPTION IONIZATION - MALDI, DIOS AND NANOSTRUCTURES Akos Veites Department on and the method of rapid heating was proposed to minimize the latter (Beuhler, et al., 1974). Lasers with respect to the ultimate size of the biomolecules (m/z Laser Ablation and its

  3. Plasma ionization by annularly bounded helicon waves Masayuki Yanoa

    E-Print Network [OSTI]

    Walker, Mitchell

    Air Force mission designs require electric propulsion devices to operate at high thrust-to-powerPlasma ionization by annularly bounded helicon waves Masayuki Yanoa and Mitchell L. R. Walkerb. In addition, the power deposition as a function of excitation frequency is derived. The solution is validated

  4. Perturbations of ionization fractions at the cosmological recombination epoch

    E-Print Network [OSTI]

    B. Novosyadlyj

    2006-05-25

    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.

  5. Ionization satellites of the ArHe dimer

    SciTech Connect (OSTI)

    Miteva, Tsveta; Klaiman, Shachar; Gokhberg, Kirill [Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany); Gromov, Evgeniy V., E-mail: Evgeniy.Gromov@pci.uni-heidelberg.de [Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany); Laboratory of Quantum Chemistry, Computer Center, Irkutsk State University, K. Marks 1, 664003 Irkutsk (Russian Federation)

    2014-05-28

    Ionization satellites are key ingredients in the control of post ionization processes such as molecular dissociation and interatomic Coulombic decay. Here, using the high-level ab initio method of multi-reference configuration interaction up to triple excitations, we study the potential energy curves (PECs) of the ionization satellites of the ArHe dimer. With this model system, we demonstrate that the simple model used in alkaline earth metal and rare gas complexes to describe the satellites as a Rydberg electron moving on top of a dicationic core does not fully hold for the rare gas clusters. The more complex valence structure in the rare gas atom leads to the mixing of different electronic configurations of the dimer. This prevents one from assigning a single dicationic parent state to some of the ionization satellites. We further analyze the structure of the different PECs, demonstrating how the density of the Rydberg electron is reflected in the structure of the PEC wherever the simple model is applicable.

  6. Tridiagonal pairs of $q$-Racah type

    E-Print Network [OSTI]

    Ito, Tatsuro

    2008-01-01

    Let $K$ denote an algebraically closed field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering $\\lbrace V_i\\rbrace_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering $\\lbrace V^*_i\\rbrace_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv) there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \

  7. How to sharpen a tridiagonal pair

    E-Print Network [OSTI]

    Ito, Tatsuro

    2008-01-01

    Let $\\F$ denote a field and let $V$ denote a vector space over $\\F$ with finite positive dimension. We consider a pair of linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering $\\lbrace V_i\\rbrace_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering $\\lbrace V^*_i\\rbrace_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv) there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \

  8. A classification of sharp tridiagonal pairs

    E-Print Network [OSTI]

    Ito, Tatsuro; Terwilliger, Paul

    2010-01-01

    Let $F$ denote a field and let $V$ denote a vector space over $F$ with finite positive dimension. We consider a pair of linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering $\\lbrace V_i\\rbrace_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering $\\lbrace V^*_i\\rbrace_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv) there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \

  9. On the shape of a tridiagonal pair

    E-Print Network [OSTI]

    Nomura, Kazumasa

    2009-01-01

    Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering $\\lbrace V_i\\rbrace_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering $\\lbrace V^*_i\\rbrace_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv) there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \

  10. The structure of a tridiagonal pair

    E-Print Network [OSTI]

    Nomura, Kazumasa

    2008-01-01

    Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering $\\{V_i\\}_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_i + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering $\\{V^*_i\\}_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_i + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv)there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \

  11. Tridiagonal pairs and the $\\mu$-conjecture

    E-Print Network [OSTI]

    Nomura, Kazumasa

    2009-01-01

    Let $F$ denote a field and let $V$ denote a vector space over $F$ with finite positive dimension. We consider a pair of linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering $\\{V_i\\}_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering $\\{V^*_i\\}_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv) there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \

  12. Towards a classification of the tridiagonal pairs

    E-Print Network [OSTI]

    Nomura, Kazumasa

    2008-01-01

    Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. Let $End(V)$ denote the $K$-algebra consisting of all $K$-linear transformations from $V$ to $V$. We consider a pair $A,A^* \\in End(V)$ that satisfy (i)--(iv) below: (i) Each of $A,A^*$ is diagonalizable. (ii) There exists an ordering $\\{V_i\\}_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$. (iii) There exists an ordering $\\{V^*_i\\}_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$. (iv) There is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \

  13. Jacobi Elliptic Monopole-Antimonopole Pair Solutions

    E-Print Network [OSTI]

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

    2012-10-01

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

  14. Pairing in bulk nuclear matter beyond BCS

    SciTech Connect (OSTI)

    Ding, D.; Dickhoff, W. H.; Dussan, H.; Witte, S. J.; Rios, A.; Polls, A.

    2014-10-15

    The influence of short-range correlations on the spectral distribution of neutrons is incorporated in the solution of the gap equation for the {sup 3}P{sub 2}?{sup 3}F{sub 2} coupled channel in pure neutron matter. This effect is studied for different realistic interactions including one based on chiral perturbation theory. The gap in this channel vanishes at all relevant densities due to the treatment of these correlations. We also consider the effect of long-range correlations by including polarization terms in addition to the bare interaction which allow the neutrons to exchange density and spin fluctuations governed by the strength of Landau parameters allowed to have reasonable values consistent with the available literature. Preliminary results indicate that reasonable values of these parameters do not generate a gap in the {sup 3}P{sub 2}?{sup 3}F{sub 2} coupled channel either for all three realistic interactions although the pairing interaction becomes slightly more attractive.

  15. Vacuum ultraviolet mass-analyzed threshold ionization spectroscopy of methylcyclohexane in the supersonic jet

    E-Print Network [OSTI]

    Kim, Sang Kyu

    Vacuum ultraviolet mass-analyzed threshold ionization spectroscopy of methylcyclohexane t Vacuum ultraviolet (VUV) mass-analyzed threshold ionization (MATI) spectrum of supersonically cooled the vacuum ultraviolet (VUV) laser source is particu- larly useful for molecular systems with no stable

  16. Spatiotemporal characterization of ionizing radiation induced DNA damage foci and their relation to chromatin organization

    E-Print Network [OSTI]

    Costes, Sylvain V

    2010-01-01

    germ cells and after low-dose gamma-radiation: relationshipsexposure to low doses of ionizing radiation. Mutat Res (after exposure to low doses of ionizing radiation. Mutat Res

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

    E-Print Network [OSTI]

    Hart, Nathan Andrew

    2012-10-19

    The above threshold ionization (ATI) spectra provide a diversity of information about a laser-atom ionization process such as laser intensity, pulse duration, carrier envelope phase, and atomic energy level spacing. However, the spatial distribution...

  18. CNT-based MEMS/NEMS gas ionizers for portable mass spectrometry applications

    E-Print Network [OSTI]

    Velasquez-Heller, Luis Fernand

    We report the fabrication and experimental characterization of a carbon nanotube (CNT)-based MEMS/NEMS electron impact gas ionizer with an integrated extractor gate for portable mass spectrometry. The ionizer achieves ...

  19. Pairing-induced speedup of nuclear spontaneous fission

    E-Print Network [OSTI]

    Jhilam Sadhukhan; J. Dobaczewski; W. Nazarewicz; J. A. Sheikh; A. Baran

    2014-10-06

    Collective inertia is strongly influenced at the level crossing at which quantum system changes diabatically its microscopic configuration. Pairing correlations tend to make the large-amplitude nuclear collective motion more adiabatic by reducing the effect of those configuration changes. Competition between pairing and level crossing is thus expected to have a profound impact on spontaneous fission lifetimes. To elucidate the role of nucleonic pairing on spontaneous fission, we study the dynamic fission trajectories of $^{264}$Fm and $^{240}$Pu using the state-of-the-art self-consistent framework. We employ the superfluid nuclear density functional theory with the Skyrme energy density functional SkM$^*$ and a density-dependent pairing interaction. Along with shape variables, proton and neutron pairing correlations are taken as collective coordinates. The collective inertia tensor is calculated within the nonperturbative cranking approximation. The fission paths are obtained by using the least action principle in a four-dimensional collective space of shape and pairing coordinates. Pairing correlations are enhanced along the minimum-action fission path. For the symmetric fission of $^{264}$Fm, where the effect of triaxiality on the fission barrier is large, the geometry of fission pathway in the space of shape degrees of freedom is weakly impacted by pairing. This is not the case for $^{240}$Pu where pairing fluctuations restore the axial symmetry of the dynamic fission trajectory. The minimum-action fission path is strongly impacted by nucleonic pairing. In some cases, the dynamical coupling between shape and pairing degrees of freedom can lead to a dramatic departure from the static picture. Consequently, in the dynamical description of nuclear fission, particle-particle correlations should be considered on the same footing as those associated with shape degrees of freedom.

  20. Nonlinear dynamics of ionization stabilization of atoms in intense laser fields

    E-Print Network [OSTI]

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

    2014-12-06

    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.

  1. Some Efficient Algorithms for the Final Exponentiation of T Pairing

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    Some Efficient Algorithms for the Final Exponentiation of T Pairing Masaaki Shirase1 , Tsuyoshi by the recent improvements, e.g., the Duursma-Lee algorithm and T pairing. In this paper we discuss how propose some efficient algorithms using the torus T2(F33n ) that can efficiently compute an inversion

  2. 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

  3. Crew Pairing Optimization with Genetic Harry Kornilakis and Panagiotis Stamatopoulos

    E-Print Network [OSTI]

    Panagiotis, Stamatopoulos

    - tions. The purpose of the crew pairing problem is to generate a set of pairings with minimal cost with near optimal cost. This problem, which is modelled by a set covering formulation, is solved with a genetic algorithm. The presented method was tested on actual flight data of Olympic Airways. 1

  4. Pair Production of Topological anti de Sitter Black Holes

    E-Print Network [OSTI]

    R. B. Mann

    1996-07-28

    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.

  5. Pairing-Based Onion Routing with Improved Forward Secrecy

    E-Print Network [OSTI]

    Goldberg, Ian

    , Security Additional Key Words and Phrases: Onion routing, Tor, pairing-based cryptography, anonymous key29 Pairing-Based Onion Routing with Improved Forward Secrecy ANIKET KATE, GREG M. ZAVERUCHA, and IAN GOLDBERG University of Waterloo This article presents new protocols for onion routing anonymity

  6. Density-matrix functionals for pairing in mesoscopic superconductors

    E-Print Network [OSTI]

    Denis Lacroix; Guillaume Hupin

    2010-09-03

    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.

  7. Efficient Implementation of Bilinear Pairings on ARM Processors

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    Efficient Implementation of Bilinear Pairings on ARM Processors Gurleen Grewal1 , Reza Azarderakhsh-Ate pairing over Barreto-Naehrig curves in software at differ- ent security levels on ARM processors. We computation on ARM-powered devices, outperforming by at least a factor of 3.7 the best previous results

  8. RNS arithmetic in Fpk and application to fast pairing computation

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    RNS arithmetic in Fpk and application to fast pairing computation Sylvain Duquesne IRMAR, UMR CNRS and their extensions of small degree. We explain why it is very interesting to use RNS arithmetic for the base field Fp the case for pairing computations on ordinary curves (as MNT or BN curves). We prove that using RNS can

  9. Minimizing communication in all-pairs shortest paths Edgar Solomonik

    E-Print Network [OSTI]

    California at Berkeley, University of

    Minimizing communication in all-pairs shortest paths Edgar Solomonik Aydin Buluc James Demmel;Copyright © 2013, by the author(s). All rights reserved. Permission to make digital or hard copies of all, requires prior specific permission. #12;Minimizing communication in all-pairs shortest paths Edgar

  10. Nature Macmillan Publishers Ltd 1998 Paired-spike interactions

    E-Print Network [OSTI]

    Reid, R. Clay

    Nature © Macmillan Publishers Ltd 1998 8 Paired-spike interactions and synaptic efficacy of retinal that information encoded in the high firing rate of an individual retinal ganglion cell becomes distributed among is transmitted to the next level of processing. We made simultaneous recordings from 205 pairs of neurons

  11. Proteomic Analysis of Low Dose Arsenic and Ionizing Radiation Exposure on Keratinocytes

    E-Print Network [OSTI]

    Rocke, David M.

    Proteomic Analysis of Low Dose Arsenic and Ionizing Radiation Exposure on Keratinocytes Susanne R that keratinocytes responded to either low dose arsenic and/or low dose ionizing radiation exposure, resulting arsenic; human; ionizing radiation; keratinocyte; low dose *Corresponding author: Susanne Berglund

  12. Pulsed-field ionization spectroscopy of high Rydberg states ,,n=50200... -benzene...chromium

    E-Print Network [OSTI]

    Kim, Sang Kyu

    Pulsed-field ionization spectroscopy of high Rydberg states ,,n=50­200... of bis,, 6 -benzene The ionization behavior of the high Rydberg states of bis 6 -benzene chromium in the presence of ac and/or dc are due to np Rydberg series. Based on the understanding of the ionization behavior of bis 6 -benzene

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

    E-Print Network [OSTI]

    and Aerospace Engineering, Princeton University, Princeton, New Jersey 08543, USA Received 30 March 2005 was accessed 10,11 . The experimental success was achieved using a gas jet of propane, subse- quently ionized of propane opens up the question of coupling in a partially ionized gas. Any additional ionization during

  14. Relativistic cross sections of the electron-impact ionization of heliumlike ions Tien-Yow Kuo1

    E-Print Network [OSTI]

    . A complete theoretical kinematic analysis of the electron- impact ionization process 29 and electron interest in atomic structure and collision mechanisms. In particular, knowledge of ionization cross

  15. Leonard pairs and the q-Racah polynomials

    E-Print Network [OSTI]

    Paul Terwilliger

    2008-07-24

    Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider an ordered pair of linear transformations $A:V\\to V$ and $A^*:V\\to V$ that satisfy conditions (i), (ii) below. (i) There exists a basis for $V$ with respect to which the matrix representing $A$ is irreducible tridiagonal and the matrix representing $A^*$ is diagonal. (ii) There exists a basis for $V$ with respect to which the matrix representing $A$ is diagonal and the matrix representing $A^*$ is irreducible tridiagonal. We call such a pair a {\\it Leonard pair} on $V$. We discuss a correspondence between Leonard pairs and a class of orthogonal polynomials consisting of the $q$-Racah polynomials and some related polynomials of the Askey scheme. For the polynomials in this class we obtain the 3-term recurrence, difference equation, Askey-Wilson duality, and orthogonality in a uniform manner using the corresponding Leonard pair.

  16. Semiclassical pair production rate for rotating electric fields

    E-Print Network [OSTI]

    Eckhard Strobel; She-Sheng Xue

    2015-02-09

    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.

  17. Relativistic tunneling picture of electron-positron pair creation

    E-Print Network [OSTI]

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

    2015-03-19

    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.

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

    SciTech Connect (OSTI)

    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

    2014-12-11

    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.

  19. Ionization-Induced Electron Trapping inUltrarelativistic Plasma Wakes

    SciTech Connect (OSTI)

    Oz, E.; Deng, S.; Katsouleas, T.; Muggli, P.; Barnes, C.D.; Blumenfeld, I.; Decker, F.J.; Emma, P.; Hogan, M.J.; Ischebeck, R.; Iverson, R.H.; Kirby, N.; Krejcik, P.; O'Connell, C.; Siemann, R.H.; Walz, D.; Auerbach, D.; Clayton, C.E.; Huang, C.; Johnson, D.K.; Joshi, C.; /UCLA

    2007-04-06

    The onset of trapping of electrons born inside a highly relativistic, 3D beam-driven plasma wake is investigated. Trapping occurs in the transition regions of a Li plasma confined by He gas. Li plasma electrons support the wake, and higher ionization potential He atoms are ionized as the beam is focused by Li ions and can be trapped. As the wake amplitude is increased, the onset of trapping is observed. Some electrons gain up to 7.6 GeV in a 30.5 cm plasma. The experimentally inferred trapping threshold is at a wake amplitude of 36 GV/m, in good agreement with an analytical model and PIC simulations.

  20. Ionization of ethane, butane, and octane in strong laser fields

    SciTech Connect (OSTI)

    Palaniyappan, Sasi; Mitchell, Rob; Ekanayake, N.; Watts, A. M.; White, S. L.; Sauer, Rob; Howard, L. E.; Videtto, M.; Mancuso, C.; Wells, S. J.; Stanev, T.; Wen, B. L.; Decamp, M. F.; Walker, B. C.

    2010-10-15

    Strong-field photoionization of ethane, butane, and octane are reported at intensities from 10{sup 14} to 10{sup 17} W/cm{sup 2}. The molecular fragment ions, C{sup +} and C{sup 2+}, are created in an intensity window from 10{sup 14} to 10{sup 15} W/cm{sup 2} and have intensity-dependent yields similar to the molecular fragments C{sub m}H{sub n}{sup +} and C{sub m}H{sub n}{sup 2+}. In the case of C{sup +}, the yield is independent of the molecular parent chain length. The ionization of more tightly bound valence electrons in carbon (C{sup 3+} and C{sup 4+}) has at least two contributing mechanisms, one influenced by the parent molecule size and one resulting from the tunneling ionization of the carbon ion.

  1. X-ray reflection spectra from ionized slabs

    E-Print Network [OSTI]

    R. R. Ross; A. C. Fabian; A. J. Young

    1999-02-23

    X-ray reflection spectra are an important component in the X-ray spectra of many active galactic nuclei and Galactic black hole candidates. It is likely that reflection takes place from highly ionized surfaces of the accretion disc in some cases. This can lead to strong Comptonization of the emergent iron, and other, absorption and emission features. We present such reflection spectra here, computed in a self-consistent manner with the method described by Ross and Fabian. In particular we emphasise the range where the ionization parameter (the flux to density ratio) \\xi is around and above 10^4. Such spectra may be relevant to the observed spectral features found in black hole candidates such as Cygnus X-1 in the low/hard state.

  2. Absolute beam emittance measurements at RHIC using ionization profile monitors

    SciTech Connect (OSTI)

    Minty, M.; Connolly, R; Liu, C.; Summers, T.; Tepikian, S.

    2014-08-15

    In the past, comparisons between emittance measurements obtained using ionization profile monitors, Vernier scans (using as input the measured rates from the zero degree counters, or ZDCs), the polarimeters and the Schottky detectors evidenced significant variations of up to 100%. In this report we present studies of the RHIC ionization profile monitors (IPMs). After identifying and correcting for two systematic instrumental errors in the beam size measurements, we present experimental results showing that the remaining dominant error in beam emittance measurements at RHIC using the IPMs was imprecise knowledge of the local beta functions. After removal of the systematic errors and implementation of measured beta functions, precise emittance measurements result. Also, consistency between the emittances measured by the IPMs and those derived from the ZDCs was demonstrated.

  3. INTERACTION OF MUON BEAM WITH PLASMA DEVELOPED DURING IONIZATION COOLING

    SciTech Connect (OSTI)

    S. Ahmed, D. Kaplan, T. Roberts, L. Spentzouris, K. Beard

    2012-07-01

    Particle-in-cell simulations involving the interaction of muon beam (peak density 10{sup 18} m{sup 3}) with Li plasma (ionized medium) of density 10{sup 16}-10{sup 22} m{sup -3} have been performed. This study aimed to understand the effects of plasma on an incoming beam in order to explore scenario developed during the process of ionization cooling. The computer code takes into account the self-consistent electromagnetic effects of beam interacting with plasma. This study shows that the beam can pass through the plasma of densities four order of magnitude higher than its peak density. The low density plasmas are wiped out by the beam, however, the resonance is observed for densities of similar order. Study reveals the signature of plasma wakefield acceleration.

  4. Colliding ionization injection in a beam driven plasma accelerator

    E-Print Network [OSTI]

    Wan, Y; Li, F; Wu, Y P; Hua, J F; Pai, C -H; Lu, W; Joshi, C; Mori, W B; Gu, Y Q

    2015-01-01

    The proposal of generating high quality electron bunches via ionization injection triggered by an counter propagating laser pulse inside a beam driven plasma wake is examined via two-dimensional particle-in-cell simulations. It is shown that electron bunches obtained using this technique can have extremely small slice energy spread, because each slice is mainly composed of electrons ionized at the same time. Another remarkable advantage is that the injection distance is changeable. A bunch with normalized emittance of 3.3 nm, slice energy spread of 15 keV and brightness of 7.2 A m$^{-2}$ rad$^{-2}$ is obtained with an optimal injection length which is achieved by adjusting the launch time of the drive beam or by changing the laser focal position. This makes the scheme a promising approach to generate high quality electron bunches for the fifth generation light source.

  5. Subcellular analysis by laser ablation electrospray ionization mass spectrometry

    DOE Patents [OSTI]

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

    2014-12-02

    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.

  6. High-resolution ionization detector and array of such detectors

    DOE Patents [OSTI]

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

    2001-01-16

    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.

  7. Multiphoton inner-shell ionization of the carbon atom

    E-Print Network [OSTI]

    Rey, H F

    2015-01-01

    We apply time-dependent R-matrix theory to study inner-shell ionization of C atoms in ultra-short high-frequency light fields with a photon energy between 170 and 245 eV. At an intensity of 10$^{17}$ W/cm$^2$, ionization is dominated by single-photon emission of a $2\\ell$ electron, with two-photon emission of a 1s electron accounting for about 2-3\\% of all emission processes, and two-photon emission of $2\\ell$ contributing about 0.5-1\\%. Three-photon emission of a 1s electron is estimated to contribute about 0.01-0.03\\%. Around a photon energy of 225 eV, two-photon emission of a 1s electron, leaving C$^+$ in either 1s2s2p$^3$ or 1s2p$^4$ is resonantly enhanced by intermediate 1s2s$^2$2p$^3$ states. The results demonstrate the capability of time-dependent R-matrix theory to describe inner-shell ionization processes including rearrangement of the outer electrons.

  8. Neutron-proton pairing correlations in odd mass systems

    SciTech Connect (OSTI)

    Fellah, M. Allal, N. H.; Oudih, M. R.

    2015-03-30

    An expression of the ground-state which describes odd mass systems within the BCS approach in the isovector neutron-proton pairing case is proposed using the blocked level technique. The gap equations as well as the energy expression are then derived. It is shown that they exactly generalize the expressions obtained in the pairing between like-particles case. The various gap parameters and the energy are then numerically studied as a function of the pairing-strength within the schematic one-level model.

  9. Photon-pair generation in random nonlinear layered structures

    E-Print Network [OSTI]

    Jan Perina Jr; Marco Centini; Concita Sibilia; Mario Bertolotti

    2009-08-25

    Nonlinearity and sharp transmission spectra of random 1D nonlinear layered structures are combined together to produce photon pairs with extremely narrow spectral bandwidths. Indistinguishable photons in a pair are nearly unentangled. Also two-photon states with coincident frequencies can be conveniently generated in these structures if photon pairs generated into a certain range of emission angles are superposed. If two photons are emitted into two different resonant peaks, the ratio of their spectral bandwidths may differ considerably from one and two photons remain nearly unentangled.

  10. Pairs Emission in a Uniform Background Field: an Algebraic Approach

    E-Print Network [OSTI]

    Roberto Soldati

    2011-06-23

    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.

  11. Effective field theory for dilute fermions with pairing

    SciTech Connect (OSTI)

    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

    2007-11-15

    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.

  12. Chiral three-nucleon forces and pairing in nuclei

    SciTech Connect (OSTI)

    Lesinski, Thomas; Hebeler, K.; Duguet, Thomas C; Schwenk, Achim

    2012-01-01

    We present the first study of pairing in nuclei including three-nucleon forces. We perform systematic calculations of the odd-even mass staggering generated using a microscopic pairing interaction at first order in chiral low-momentum interactions. Significant repulsive contributions from the leading chiral three-nucleon forces are found. Two- and three-nucleon interactions combined account for approximately 70% of the experimental pairing gaps, which leaves room for self-energy and induced interaction effects that are expected to be overall attractive in nuclei.

  13. Stress-free BCS pairing in color superconductors is impossible

    E-Print Network [OSTI]

    Krishna Rajagopal; Andreas Schmitt

    2006-10-26

    Cold, asymptotically dense three-flavor quark matter is in the color-flavor locked (CFL) phase, in which all quarks pair in a particularly symmetric fashion. At smaller densities, taking into account a nonzero strange quark mass and electric and color neutrality, the CFL phase requires pairing of quarks with mismatched Fermi momenta. We present a classification of all other possible, less symmetric, pairing patterns and prove that none of them can avoid this mismatch. This result suggests unconventional, e.g., spatially inhomogeneous, superconducting phases for moderate densities.

  14. PHYSICAL REVIEW A 84, 043429 (2011) Orientation dependence of the ionization of CO and NO in an intense femtosecond

    E-Print Network [OSTI]

    Kling, Matthias

    2011-01-01

    on this idea was proposed, which proposes favored ionization of carbonyl sulfide (OCS) for an orientation

  15. One-Photon Mass-Analyzed Threshold Ionization Spectroscopy of trans-and cis-1-C3H5Br: Ionization Energies and Vibrational Assignments for the Cations

    E-Print Network [OSTI]

    Kim, Myung Soo

    two-photon 1 + 1 scheme5 and ionized by pulsed electric field (pulsed field ionization, PFI is recorded that is virtually the vibration-rotation spectrum of the corresponding cation. Mass to spectral interpretation even though the irregularly spaced torsional overtones have not been observed

  16. Two-dimensional simulations of pulsational pair-instability supernovae...

    Office of Scientific and Technical Information (OSTI)

    thermonuclear outbursts due to a recurring pair-instability. In some of these events, solar masses of material are ejected in repeated outbursts of several 10sup 50 erg...

  17. Single-Pair FRET Characterization of DNA Tweezers

    E-Print Network [OSTI]

    Ludwig-Maximilians-Universität, München

    Single-Pair FRET Characterization of DNA Tweezers Barbara K. Mu1ller, Andreas Reuter, Friedrich C-Champaign, 1110 West Green Street, Urbana, Illinois 61801 Received August 18, 2006; Revised Manuscript Received

  18. Emission of neutrino-antineutrino pairs by hadronic bremsstrahlung processes

    E-Print Network [OSTI]

    Bacca, Sonia; Schwenk, Achim

    2015-01-01

    We review our recent calculations of neutrino-antineutrino pair production from bremsstrahlung processes in hadronic collisions at temperature and densities relevant for core-collapse supernovae. We focus on neutron-neutron and neutron-alpha collisions.

  19. MENTORING PAIRINGS (plus others with mentors in common)

    E-Print Network [OSTI]

    May, J. Peter

    -mails, and mentors. (All e-mails are @midway.uchicago.edu.) Philip Ascher pa7 Fowler, Scheels, and Iyer Emil Bojanov and Patel Emily Witt emily1 Amin and Patel #12;MENTORING PAIRINGS 3 SESAME Graduate students and e

  20. Measurement of the top quark pair production cross section in...

    Office of Scientific and Technical Information (OSTI)

    Measurement of the top quark pair production cross section in proton-proton collisions at sqrts13 TeV Citation Details In-Document Search Title: Measurement of the top quark...

  1. Monojet plus soft dilepton signal from light higgsino pair production...

    Office of Scientific and Technical Information (OSTI)

    Monojet plus soft dilepton signal from light higgsino pair production at LHC14 Citation Details In-Document Search This content will become publicly available on December 8, 2015...

  2. The Nuclear Pairing Gap -- How Low Can It Go?

    E-Print Network [OSTI]

    B. Alex Brown

    2013-08-16

    The pairing gap for $^{53}$Ca obtained from new experimental data on the masses of $^{52-54}$Ca has the smallest value yet observed. This is explained in the framework of the nuclear shell model with schematic and realistic Hamiltonians as being due to shell gaps around the low-$ j $ orbital $ 1p_{1/2} $. Minima in the pairing gaps for all nuclei are shown and discussed

  3. Possibility of Pairing-Induced Even-Denominator Fractional Quantum

    E-Print Network [OSTI]

    Scarola, Vito

    fermions (CFs) B* = B ­2p0 Effective Field = 0 / B * = 0 / |B*| } = */(2p * 1)+- Effective Filling at = 5/2 ( Willett et. al. '87, Pan et. al `99) Novel p-wave paired state of CFs at = 5/2 : Electrons transform into CFs and pair up to yield a gap and hence FQHE MR = (zj -zk) 2 Pf[ (zj - zk) -1] (Moore, Read

  4. Prolific pair production with high-power lasers

    E-Print Network [OSTI]

    Bell, A R

    2008-01-01

    Prolific electron-positron pair production is possible at laser intensities approaching 10^{24} W/cm^2 at a wavelength of 1 micron. An analysis of electron trajectories and interactions at the nodes (B=0) of two counter-propagating, circularly polarised laser beams shows that a cascade of gamma-rays and pairs develops. The geometry is generalised qualitatively to linear polarisation and laser beams incident on a solid target.

  5. Prolific pair production with high-power lasers

    E-Print Network [OSTI]

    A. R. Bell; John G. Kirk

    2008-10-16

    Prolific electron-positron pair production is possible at laser intensities approaching 10^{24} W/cm^2 at a wavelength of 1 micron. An analysis of electron trajectories and interactions at the nodes (B=0) of two counter-propagating, circularly polarised laser beams shows that a cascade of gamma-rays and pairs develops. The geometry is generalised qualitatively to linear polarisation and laser beams incident on a solid target.

  6. Randomly poled crystals as a source of photon pairs

    E-Print Network [OSTI]

    Jan Perina Jr; Jiri Svozilik

    2011-01-04

    Generation of photon pairs from randomly poled nonlinear crystals is investigated using analytically soluble model and numerical calculations. Randomly poled crystals are discovered as sources of entangled ultra broad-band signal and idler fields. Their photon-pair generation rates scale linearly with the number of domains. Entanglement times as short as several fs can be reached. Comparison with chirped periodically-poled structures is given and reveals close similarity.

  7. Formation of Cooper pairs as a consequence of exchange interaction

    E-Print Network [OSTI]

    Stanislav Dolgopolov

    2015-04-13

    The pairing of two electrons with antiparallel spins may minimize the energy of each of the paired electrons. Thus the exchange interaction and the Pauli Exclusion Principle cause a bond between two electrons in a crystal. This can be proved analyzing the energy of each conduction electron in the field of a crystal on assumption that all other kinds of magnetic spin ordering in the crystal are weak. The superconductivity in a metallic crystal occurs only if conduction electrons before the pairing are put closely on the Fermi surface in the momentum space. The motion of conduction electrons in the crystal may disturb the formation of Cooper pairs, because the kinetic energy of the motion is usually much larger than the energy gap of superconductor. The conduction electrons as standing waves have a zero momentum, hence their momentums are synchronous; consequently the formation of Cooper pairs is more probable than in case of electrons with nonzero momentums. The total momentum of the pair of two electrons as standing waves is zero.

  8. Pair-instability supernovae in the local universe

    SciTech Connect (OSTI)

    Whalen, Daniel J. [Zentrum für Astronomie, Institut für Theoretische Astrophysik, Universität Heidelberg, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Smidt, Joseph [CCS-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Heger, Alexander [Monash Centre for Astrophysics, Monash University, Victoria 3800 (Australia); Hirschi, Raphael [Astrophysics Group, EPSAM, University of Keele, Lennard-Jones Labs, Keele ST5 5BG (United Kingdom); Yusof, Norhasliza [Department of Physics, University of Malaysia, 50603 Kuala Lampur (Malaysia); Even, Wesley; Fryer, Chris L. [T-2, 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); Chen, Ke-Jung [Department of Astronomy and Astrophysics, UCSC, Santa Cruz, CA 95064 (United States); Joggerst, Candace C. [XTD-3, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2014-12-10

    The discovery of 150-300 M {sub ?} stars in the Local Group and pair-instability supernova candidates at low redshifts has excited interest in this exotic explosion mechanism. Realistic light curves for pair-instability supernovae at near-solar metallicities are key to identifying and properly interpreting these events as more are found. We have modeled pair-instability supernovae of 150-500 M {sub ?} Z ? 0.1-0.4 Z {sub ?} stars. These stars lose up to 80% of their mass to strong line-driven winds and explode as bare He cores. We find that their light curves and spectra are quite different from those of Population III pair-instability explosions, which therefore cannot be used as templates for low-redshift events. Although non-zero metallicity pair-instability supernovae are generally dimmer than their Population III counterparts, in some cases they will be bright enough to be detected at the earliest epochs at which they can occur, the formation of the first galaxies at z ? 10-15. Others can masquerade as dim, short duration supernovae that are only visible in the local universe and that under the right conditions could be hidden in a wide variety of supernova classes. We also report for the first time that some pair-instability explosions can create black holes with masses of ?100 M {sub ?}.

  9. On magnon mediated Cooper pair formation in ferromagnetic superconductors

    SciTech Connect (OSTI)

    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)

    2014-08-15

    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.

  10. Modeling of transient ionizing radiation effects in bipolar devices at high dose-rates

    SciTech Connect (OSTI)

    FJELDLY,T.A.; DENG,Y.; SHUR,M.S.; HJALMARSON,HAROLD P.; MUYSHONDT,ARNOLDO

    2000-04-25

    To optimally design circuits for operation at high intensities of ionizing radiation, and to accurately predict their a behavior under radiation, precise device models are needed that include both stationary and dynamic effects of such radiation. Depending on the type and intensity of the ionizing radiation, different degradation mechanisms, such as photoelectric effect, total dose effect, or single even upset might be dominant. In this paper, the authors consider the photoelectric effect associated with the generation of electron-hole pairs in the semiconductor. The effects of low radiation intensity on p-II diodes and bipolar junction transistors (BJTs) were described by low-injection theory in the classical paper by Wirth and Rogers. However, in BJTs compatible with modem integrated circuit technology, high-resistivity regions are often used to enhance device performance, either as a substrate or as an epitaxial layer such as the low-doped n-type collector region of the device. Using low-injection theory, the transient response of epitaxial BJTs was discussed by Florian et al., who mainly concentrated on the effects of the Hi-Lo (high doping - low doping) epilayer/substrate junction of the collector, and on geometrical effects of realistic devices. For devices with highly resistive regions, the assumption of low-level injection is often inappropriate, even at moderate radiation intensities, and a more complete theory for high-injection levels was needed. In the dynamic photocurrent model by Enlow and Alexander. p-n junctions exposed to high-intensity radiation were considered. In their work, the variation of the minority carrier lifetime with excess carrier density, and the effects of the ohmic electric field in the quasi-neutral (q-n) regions were included in a simplified manner. Later, Wunsch and Axness presented a more comprehensive model for the transient radiation response of p-n and p-i-n diode geometries. A stationary model for high-level injection in p-n junctions was developed by Isaque et al. They used a more complete ambipolar transport equation, which included the dependencies of the transport parameters (ambipolar diffusion constant, mobility, and recombination rate) on the excess minority carrier concentration. The expression used for the recombination rate was that of Shockley-Reed-Hall (SRH) recombination which is dominant for low to mid-level radiation intensities. However, at higher intensities, Auger recombination becomes important eventually dominant. The complete ambipolar transport equation including the complicated dependence of transport parameters on the radiation intensity, cannot be solved analytically. This solution is obtained for each of the regimes where a given recombination mechanism dominates, and then by joining these solutions using appropriate smoothing functions. This approach allows them to develop a BJT model accounting for the photoelectric effect of the ionizing radiation that can be implemented in SPICE.

  11. INSTABILITY OF MAGNETIZED IONIZATION FRONTS SURROUNDING H II REGIONS

    SciTech Connect (OSTI)

    Kim, Jeong-Gyu; Kim, Woong-Tae, E-mail: jgkim@astro.snu.ac.kr, E-mail: wkim@astro.snu.ac.kr [Center for the Exploration of the Origin of the Universe (CEOU), Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2014-12-20

    An ionization front (IF) surrounding an H II region is a sharp interface where a cold neutral gas makes the transition to a warm ionized phase by absorbing UV photons from central stars. We investigate the instability of a plane-parallel D-type IF threaded by parallel magnetic fields, by neglecting the effects of recombination within the ionized gas. We find that weak D-type IFs always have the post-IF magnetosonic Mach number M{sub M2}?1. For such fronts, magnetic fields increase the maximum propagation speed of the IFs, while reducing the expansion factor ? by a factor of 1 + 1/(2?{sub 1}) compared to the unmagnetized case, with ?{sub 1} denoting the plasma beta in the pre-IF region. IFs become unstable to distortional perturbations owing to gas expansion across the fronts, exactly analogous to the Darrieus-Landau instability of ablation fronts in terrestrial flames. The growth rate of the IF instability is proportional linearly to the perturbation wavenumber, as well as the upstream flow speed, and approximately to ?{sup 1/2}. The IF instability is stabilized by gas compressibility and becomes completely quenched when the front is D-critical. The instability is also stabilized by magnetic pressure when the perturbations propagate in the direction perpendicular to the fields. When the perturbations propagate in the direction parallel to the fields, on the other hand, it is magnetic tension that reduces the growth rate, completely suppressing the instability when M{sub M2}{sup 2}<2/(2?{sub 1}?1). When the front experiences an acceleration, the IF instability cooperates with the Rayleigh-Taylor instability to make the front more unstable.

  12. Miniature quadrupole mass spectrometer having a cold cathode ionization source

    DOE Patents [OSTI]

    Felter, Thomas E. (Livermore, CA)

    2002-01-01

    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.

  13. Photo-ionization and residual electron effects in guided streamers

    SciTech Connect (OSTI)

    Wu, S.; Lu, X. Liu, D.; Yang, Y.; Pan, Y.; Ostrikov, K.

    2014-10-15

    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.

  14. Breakdown of the Dipole Approximation in Strong-Field Ionization

    E-Print Network [OSTI]

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

    2014-10-02

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

  15. THE TRUE COST OF PAIR PROGRAMMING: DEVELOPMENT OF A COMPREHENSIVE MODEL AND TEST

    E-Print Network [OSTI]

    Sun, Wenying

    2011-09-19

    To advance the nomological net and theory, this dissertation proposed a comprehensive pair programming research model where the relationships among system complexity, programming methods, pair composition, effort, duration, ...

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

    E-Print Network [OSTI]

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

    2011-01-01

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

  17. Mass spectral characterization of oxygen-containing aromatics with methanol chemical ionization

    SciTech Connect (OSTI)

    Buchanan, M.V.

    1984-03-01

    Chemical ionization mass spectrometry with methanol and deuterated methanol as ionization reagents is used to differentiate oxygen-containing aromatics, including phenols, aromatic ethers, and aromatic substituted alcohols, as well as compounds containing more than one oxygen atom. The analogous sulfur-containing aromatics may be similarly differentiated. Methanol chemical ionization is used to characterize a neutral aromatic polar subfraction of a coal-derived liquid by combined gas chromatography/mass spectrometry. 16 references, 2 tables, 1 figure.

  18. Polarization operator approach to pair creation in short laser pulses

    E-Print Network [OSTI]

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

    2015-01-28

    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.

  19. Modulated pair condensate of p-orbital ultracold fermions

    SciTech Connect (OSTI)

    Zhang Zixu; Zhao Erhai; Liu, W. Vincent; Hung, Hsiang-Hsuan; Ho, Chiu Man

    2010-09-15

    We show that an interesting kind of pairing occurs for spin-imbalanced Fermi gases under a specific experimental condition--the spin up and spin down Fermi levels lying within the p{sub x} and s orbital bands of an optical lattice, respectively. The pairs condense at a finite momentum equal to the sum of the two Fermi momenta of spin up and spin down fermions and form a p-orbital pair condensate. This 2k{sub F} momentum dependence has been seen before in spin- and charge-density waves, but it differs from the usual p-wave superfluids such as {sup 3}He, where the orbital symmetry refers to the relative motion within each pair. Our conclusion is based on the density matrix renormalization group analysis for the one-dimensional (1D) system and mean-field theory for the quasi-1D system. The phase diagram of the quasi-1D system is calculated, showing that the p-orbital pair condensate occurs in a wide range of fillings. In the strongly attractive limit, the system realizes an unconventional BEC beyond Feynman's no-node theorem. The possible experimental signatures of this phase in molecule projection experiment are discussed.

  20. Laser ablation electrospray ionization (LAESI) for atmospheric pressure, In vivo, and imaging mass spectrometry

    DOE Patents [OSTI]

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

    2011-11-29

    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).

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

    DOE Patents [OSTI]

    Vertes, Akos; Nemes, Peter

    2012-10-30

    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).

  2. Laser ablation electrospray ionization (LAESI) for atmospheric pressure, in vivo, and imaging mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos; Nemes, Peter

    2013-07-16

    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).

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

    DOE Patents [OSTI]

    Vertes, Akos; Nemes, Peter

    2013-07-16

    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).

  4. Resonance overlap structure in the microwave ionization of the hydrogen atom

    SciTech Connect (OSTI)

    Farrelly, D.; Uzer, T.

    1988-12-01

    The microwave ionization of the hydrogen atom involves most of the open issues concerning classical and quantum chaos. Much recent research has considered quasi-one-dimensional extended states for which ionization thresholds have been estimated using a classical picture in which ionization proceeds through the overlap of an infinity of nonlinear resonances. Using a canonical transformation to Deprit's ''Lissajous elements'' which makes the two-dimensional nature of the problem explicit, an accurate and improved ionization threshold, compared to previous resonance overlap criteria, is obtained through the overlap of only two nonlinear resonances in the one-dimensional limit.

  5. Laser ablation electrospray ionization (LAESI) for atmospheric pressure, in vivo, and imaging mass spectrometry

    SciTech Connect (OSTI)

    Vertes, Akos; Nemes, Peter

    2014-08-19

    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).

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

    E-Print Network [OSTI]

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

    2008-11-04

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

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

    DOE Patents [OSTI]

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

    2011-06-21

    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).

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

    E-Print Network [OSTI]

    Bowring, D.L.

    2014-01-01

    ON A CAVITY WITH BERYLLIUM WALLS FOR MUON IONIZATION COOLINGFabricating a cavity with beryllium walls would mitigatepillbox RF cavity with beryllium walls, in order to evaluate

  9. A Complete Relativistic Ionized Accretion Disc in Cygnus X-1

    E-Print Network [OSTI]

    A. J. Young; A. C. Fabian; R. R. Ross; Y. Tanaka

    2001-03-14

    The galactic black hole candidate Cygnus X-1 is observed to be in one of two X-ray spectral states; either the low/hard (low soft X-ray flux and a flat power law tail) or high/soft (high blackbody-like soft X-ray flux and a steep power law tail) state. The physical origin of these two states is unclear. We present here a model of an ionized accretion disc, the spectrum of which is blurred by relativistic effects, and fit it to the ASCA, Ginga and EXOSAT data of Cygnus X-1 in both spectral states. We confirm that relativistic blurring provides a much better fit to the low/hard state data and, contrary to some previous results, find the data of both states to be consistent with an ionized thin accretion disc with a reflected fraction of unity extending to the innermost stable circular orbit around the black hole. Our model is an alternative to those which, in the low/hard state, require the accretion disc to be truncated at a few tens of Schwarzschild radii, within which there is a Thomson-thin, hot accretion flow. We suggest a mechanism that may cause the changes in spectral state.

  10. Collision dynamics of proton with formaldehyde: Fragmentation and ionization

    SciTech Connect (OSTI)

    Wang, Jing; Gao, Cong-Zhang; Beijing Radiation Center, Beijing 100875 ; Calvayrac, Florent; Zhang, Feng-Shou; Beijing Radiation Center, Beijing 100875; Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000

    2014-03-28

    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.

  11. On the Escape of Ionizing Radiation from Starbursts

    E-Print Network [OSTI]

    Heckman, T; Meurer, G; Leitherer, C; Calzetti, D; Martin, C L

    2001-01-01

    Far-ultraviolet spectra obtained with $FUSE$ show that the strong $CII\\lambda$1036 interstellar absorption-line is essentially black in five of the UV-brightest local starburst galaxies. Since the opacity of the neutral ISM below the Lyman-edge will be significantly larger than in the $CII$ line, these data provide strong constraints on the escape of ionizing radiation from these starbursts. Interpreted as a a uniform absorbing slab, the implied optical depth at the Lyman edge is huge ($\\tau_0 \\geq 10^2$). Alternatively, the areal covering factor of opaque material is typically $\\geq$ 94%. Thus, the fraction of ionizing stellar photons that escape the ISM of each galaxy is small: our conservative estimates typically yield $f_{esc} \\leq 6%$. Inclusion of extinction due to dust will further decrease $f_{esc}$. An analogous analysis of the rest-UV spectrum of the star-forming galaxy $MS 1512-CB58$ at $z$ =2.7 leads to similar constraints on $f_{esc}$. These new results agree with the constraints provided by dire...

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

    SciTech Connect (OSTI)

    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)

    2010-06-15

    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.

  13. Performance parameters of a liquid filled ionization chamber array

    SciTech Connect (OSTI)

    Poppe, B.; Stelljes, T. S.; Looe, H. K.; Chofor, N.; Harder, D.; Willborn, K.

    2013-08-15

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

  14. Spices form the basis of food pairing in Indian cuisine

    E-Print Network [OSTI]

    Jain, Anupam; Bagler, Ganesh

    2015-01-01

    Culinary practices are influenced by climate, culture, history and geography. Molecular composition of recipes in a cuisine reveals patterns in food preferences. Indian cuisine encompasses a number of diverse sub-cuisines separated by geographies, climates and cultures. Its culinary system has a long history of health-centric dietary practices focused on disease prevention and promotion of health. We study food pairing in recipes of Indian cuisine to show that, in contrast to positive food pairing reported in some Western cuisines, Indian cuisine has a strong signature of negative food pairing; more the extent of flavor sharing between any two ingredients, lesser their co-occurrence. This feature is independent of recipe size and is not explained by ingredient category-based recipe constitution alone. Ingredient frequency emerged as the dominant factor specifying the characteristic flavor sharing pattern of the cuisine. Spices, individually and as a category, form the basis of ingredient composition in Indian...

  15. Investigation on collisions of filament pairs in dielectric barrier discharge

    SciTech Connect (OSTI)

    Dong, Lifang; Zhang, Chao; Li, Ben; Zhang, Xinpu; He, Yafeng; Li, Xuechen; Hebei Key Laboratory of Optic-electronic Information Materials, Baoding 071002

    2013-12-15

    Collisions of filament pairs in a hexagonal superlattice pattern in dielectric barrier discharge are investigated on different timescales. In the evolution of the pattern, the space scale of each hexagon cell decreases with the increasing voltage. The duration of one collision is seven half voltage cycles at least. Two stable orientations of a pair are approximately perpendicular to each other and the orientational changes occurring during the entire colliding process should be a multiple of 30°. The time interval between two consecutive collisions decreases with the increasing voltage. The distance between the paired spots decreases nonmonotonically. Based on the discharge order of the pattern, it is inferred that the collision should be the interaction between a discharging filament and the surface charges deposited by another discharged filament, and the nonmonotonic decrease of distance D is explained.

  16. Rotation Rate of Particle Pairs in Homogeneous Isotropic Turbulence

    E-Print Network [OSTI]

    Daddi-Moussa-Ider, Abdallah

    2015-01-01

    Understanding the dynamics of particles in turbulent flow is important in many environmental and industrial applications. In this paper, the statistics of particle pair orientation is numerically studied in homogeneous isotropic turbulent flow, with Taylor microscale Rynolds number of 300. It is shown that the Kolmogorov scaling fails to predict the observed probability density functions (PDFs) of the pair rotation rate and the higher order moments accurately. Therefore, a multifractal formalism is derived in order to include the intermittent behavior that is neglected in the Kolmogorov picture. The PDFs of finding the pairs at a given angular velocity for small relative separations, reveals extreme events with stretched tails and high kurtosis values. Additionally, The PDFs are found to be less intermittent and follow a complementary error function distribution for larger separations.

  17. Effect of pairing on transfer and fusion reactions

    E-Print Network [OSTI]

    Scamps, Guillaume

    2014-01-01

    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.

  18. Pair Winds in Schwarzschild Spacetime with Application to Strange Stars

    E-Print Network [OSTI]

    A. G. Aksenov; M. Milgrom; V. V. Usov

    2007-01-09

    We present the results of numerical simulations of stationary, spherically outflowing, electron-positron pair winds, with total luminosities in the range 10^{34}--10^{42} ergs/s. In the concrete example described here, the wind injection source is a hot, bare, strange star, predicted to be a powerful source of pairs created by the Coulomb barrier at the quark surface. We find that photons dominate in the emerging emission, and the emerging photon spectrum is rather hard and differs substantially from the thermal spectrum expected from a neutron star with the same luminosity. This might help distinguish the putative bare strange stars from neutron stars.

  19. A pair spectrometer for measuring multipolarities of energetic nuclear transitions

    E-Print Network [OSTI]

    Gulyás, J; Krasznahorkay, A J; Csatlós, M; Csige, L; Gácsi, Z; Hunyadi, M; Krasznahorkay, A; Vitéz, A; Tornyi, T G

    2015-01-01

    A multi-detector array has been designed and constructed for the simultaneous measurement of energy- and angular correlations of electron-positron pairs. Experimental results are obtained over a wide angular range for high-energy transitions in 16O, 12C and 8Be. A comparison with GEANT simulations demonstrates that angular correlations between 50 and 180 degrees of the electron-positron pairs in the energy range between 6 and 18 MeV can be determined with sufficient resolution and efficiency.

  20. Error-prevention scheme with two pairs of qubits

    E-Print Network [OSTI]

    Chu, Shih-I; Yang, Chui-Ping; Han, Siyuan

    2002-09-04

    Ei jue ie j&5ue je i& , e iP$0,1% @6#!. The expressions for HS and HSB are as follows: HS5e0~s I z 1s II z !, *Email address: cpyang@floquet.chem.ku.edu †Email address: sichu@ku.edu ‡ Email address: han@ku.eduError-prevention scheme Chui-Ping Yang.... The sche two pairs of qubits and through error-prevention proc through a decoherence-free subspace for collective p pairs; leakage out of the encoding space due to amp addition, how to construct decoherence-free states for n discussed. DOI: 10.1103/Phys...

  1. Measurements of the Top Quark Pair-Production Cross Section

    E-Print Network [OSTI]

    Frank-Peter Schilling

    2013-02-19

    Measurements of the inclusive and differential cross section for the production of top quark pairs in proton-(anti)proton collision at center-of-mass energies of 1.96, 7.0 and 8.0 TeV are presented and compared with the latest theory predictions and Monte-Carlo models. In addition, first measurements of the production of top quark pairs in association with additional jets or with a boson are highlighted. All measurements are in good agreement with the Standard Model.

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

    E-Print Network [OSTI]

    Bryan, W A; Newell, W R; Sanderson, J H

    2006-01-01

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

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

    E-Print Network [OSTI]

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

    2006-10-10

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

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

    SciTech Connect (OSTI)

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

    2006-11-15

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

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

    E-Print Network [OSTI]

    Gomez-Ceballos, Guillelmo

    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 ...

  6. Phenotypic assortative mating and within-pair sexual dimorphism and its influence on breeding

    E-Print Network [OSTI]

    Donázar, José A.

    Phenotypic assortative mating and within-pair sexual dimorphism and its influence on breeding. Bertellotti, and O. Ceballos Abstract: We examined within-pair sexual dimorphism and phenotypic assortative to relate the body size of each member of the pair and the degree of sexual dimorphism within pairs

  7. Bounds on the Mobility of Electrons in Weakly Ionized Plasmas A. Rokhlenko, Department of Mathematics

    E-Print Network [OSTI]

    Bounds on the Mobility of Electrons in Weakly Ionized Plasmas A. Rokhlenko, Department energy of electrons, driven by an external field in a weakly ionized plasma (swarm approximation. The bounds prove rigorously that it is possible to increase the electron mobility by the addition of suitably

  8. A Liquid Xenon Ionization Chamber in an All-fluoropolymer Vessel

    SciTech Connect (OSTI)

    LePort, F.; Pocar, A.; Bartoszek, L.; DeVoe, R.; Fierlinger, P.; Flatt, B.; Gratta, G.; Green, M.; Montero Diez, M.; Neilson, R.; O'Sullivan, K.; Wodin, J.; Woisard, D.; Baussan, E.; Breidenbach, M.; Conley, R.; Fairbank, W., Jr.; Farine, J.; Hall, K.; Hallman, D.; Hargrove, C.; /Stanford U., Phys. Dept. /Applied Plastics Technology, Bristol/Neuchatel U. /SLAC /Colorado State U. /Laurentian U. /Carleton U. /Alabama U. /Moscow, ITEP; ,

    2007-02-26

    A novel technique has been developed to build vessels for liquid xenon ionization detectors entirely out of ultra-clean fluoropolymer. We describe the advantages in terms of low radioactivity contamination, provide some details of the construction techniques, and show the energy resolution achieved with a prototype all-fluoropolymer ionization detector.

  9. Impact-ionization field-effect-transistor based biosensors for ultra-sensitive detection of biomolecules

    E-Print Network [OSTI]

    Impact-ionization field-effect-transistor based biosensors for ultra-sensitive detection online 21 May 2013) The phenomenon of impact-ionization is proposed to be leveraged for a novel biosensor field-effect-transistor (IFET) based biosensor, it is possible to obtain an increase in sensitivity

  10. Laser desorption/ionization from nanostructured surfaces: nanowires, nanoparticle films and silicon microcolumn arrays

    E-Print Network [OSTI]

    Vertes, Akos

    Laser desorption/ionization from nanostructured surfaces: nanowires, nanoparticle films and silicon for soft laser desorption/ionization (SLDI) mass spectrometry. Thin films of gold nanoparticles (with 12 to analyze a series of directly deposited polypeptide samples. In this new SLDI method, the required laser

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

    E-Print Network [OSTI]

    Zare, Richard N.

    Laser Desorption Single-Photon Ionization of Asphaltenes: Mass Range, Compound Sensitivity and flow assurance. Laser desorption single-photon ionization mass spectrometry (LDSPI-MS) has emerged, such as their molecular mass distribution and dominant molecular architecture.1,6-11 Laser mass spectrometry, including

  12. MEASURING AN ERUPTIVE PROMINENCE AT LARGE DISTANCES FROM THE SUN. I. IONIZATION AND EARLY EVOLUTION

    E-Print Network [OSTI]

    Howard, Tim

    MEASURING AN ERUPTIVE PROMINENCE AT LARGE DISTANCES FROM THE SUN. I. IONIZATION AND EARLY EVOLUTION characteristics at it moves away from the Sun. The prominence reaches complete ionization, or at least a state for an accompanying paper that reports on measurements of the prominence at large distances from the Sun using

  13. Ionization probability of atoms and molecules sputtered from a cesium covered silver surface

    E-Print Network [OSTI]

    Wucher, Andreas

    Ionization probability of atoms and molecules sputtered from a cesium covered silver surface S that the dependence of the AgCs ion fraction on the cesium surface concentration does not follow the ionization conditions by a rastered 10 keV Xe ion beam and subsequently covered with cesium by deposition from

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

    E-Print Network [OSTI]

    Thumm, Uwe

    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

  15. Isomer discrimination of polycyclic aromatic hydrocarbons in the Murchison meteorite by resonant ionization

    E-Print Network [OSTI]

    de Vries, Mattanjah S.

    Isomer discrimination of polycyclic aromatic hydrocarbons in the Murchison meteorite by resonant;Abstract We have used two-color resonant two-photon ionization (2C-R2PI) mass spectrometry to discriminate demonstrated isomer discrimination of PAHs by chemical ionization mass spectrometry with carbon dioxide

  16. Toward Single-Cell Analysis by Plume Collimation in Laser Ablation Electrospray Ionization Mass Spectrometry

    E-Print Network [OSTI]

    Vertes, Akos

    is used to deliver laser energy to a sample in laser ablation electrospray ionization (LAESI) mass with the electrospray plume resulting in increased ionization efficiency, reduced limit of detection (by a factor of 13-cell level.4 New cell isolation methods, such as laser capture microdissection, are being developed

  17. Magnetic reconnection in partially ionized plasmas Ellen G. Zweibel,1,a)

    E-Print Network [OSTI]

    Ji, Hantao

    ionization fraction. The ionization fraction in the solar chromosphere and in the so- called warm neutral energy and changing the magnetic topology. This point is becoming widely appre- ciated; see, for example quasineutrality (ne ¼ ni), and thus need only the con- tinuity equations for ions and neutrals @qi @t þ

  18. MASS SPECTROMETRY | Ionization Methods Overview DJ Harvey, University of Oxford, Oxford, UK

    E-Print Network [OSTI]

    FD Field desorption FI Field ionization GC/MS Gas chromatography/mass spectrometry HPLC High/ionization SEND Surface-enhanced neat desorption SEPAR Surface-enhanced photolabile attachment and release SIMS and involatile molecules, desorption techniques using high electric fields or bombardment with fission fragments

  19. Quantification of Ozone Levels in Indoor Environments Generated by Ionization and Ozonolysis Air Purifiers

    E-Print Network [OSTI]

    Nizkorodov, Sergey

    Quantification of Ozone Levels in Indoor Environments Generated by Ionization and Ozonolysis Air ozone (O3) during operation, either in- tentionally or as a byproduct of air ionization standards. Sev- eral types of air purifiers were tested for their ability to produce ozone in various indoor

  20. Impact Ionization Model Using Average Energy and Average Square Energy of Distribution Function

    E-Print Network [OSTI]

    Dunham, Scott

    Impact Ionization Model Using Average Energy and Average Square Energy of Distribution Function Ken relaxation length, v sat ø h''i (¸ 0:05¯m), the energy distribution function is not well described calculation of impact ionization coefficient requires the use of a high energy distribution function because

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

    DOE Patents [OSTI]

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

    1999-06-29

    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.

  2. Mass Loss Rates, Ionization Fractions, Shock Velocities and Magnetic Fields of Stellar Jets

    E-Print Network [OSTI]

    Hartigan, Patrick

    Mass Loss Rates, Ionization Fractions, Shock Velocities and Magnetic Fields of Stellar Jets Patrick the initial conditions relevant to stellar jets, and we show how to estimate the ionization fractions and shock velocities in jets directly from observations of the strong emission lines in these flows

  3. Capture into Rydberg states and momentum distributions of ionized electrons

    E-Print Network [OSTI]

    Shvetsov-Shilovski, N I; Popruzhenko, S V; Becker, W

    2009-01-01

    The yield of neutral excited atoms and low-energy photoelectrons generated by the electron dynamics in the combined Coulomb and laser field after tunneling is investigated. We present results of Monte-Carlo simulations built on the two-step semiclassical model, as well as analytic estimates and scaling relations for the population trapping into the Rydberg states. It is shown that mainly those electrons are captured into bound states of the neutral atom that due to their initial conditions (i) have moderate drift momentum imparted by the laser field and (ii) avoid strong interaction ("hard" collision) with the ion. In addition, it is demonstrated that the channel of capture, when accounted for in semiclassical calculations, has a pronounced effect on the momentum distribution of electrons with small positive energy. For the parameters that we investigated its presence leads to a dip at zero momentum in the longitudinal momentum distribution of the ionized electrons.

  4. Detailed Investigations of Interactions between Ionizing Radiation and Neutral Gases

    SciTech Connect (OSTI)

    Landers, Allen L

    2014-03-31

    We are investigating phenomena that stem from the many body dynamics associated with ionization of an atom or molecule by photon or charged particle. Our program is funded through the Department of Energy EPSCoR Laboratory Partnership Award in collaboration with Lawrence Berkeley National Laboratory. We are using variations on the well established COLTRIMS technique to measure ions and electrons ejected during these interactions. Photoionization measurements take place at the Advanced Light Source at LBNL as part of the ALS-COLTRIMS collaboration with the groups of Reinhard Dörner at Frankfurt and Ali Belkacem at LBNL. Additional experiments on charged particle impact are conducted locally at Auburn University where we are studying the dissociative molecular dynamics following interactions with either ions or electrons over a velocity range of 1 to 12 atomic units.

  5. Role of Angular Electron Pair Correlation in Stabilizing C60

    E-Print Network [OSTI]

    Simons, Jack

    then combine to trap electrons of singlet C60 2 from detaching, thus producing the very long observed lifetimes with its long lifetime resulting from the need for an electron to tunnel through a barrier to undergoRole of Angular Electron Pair Correlation in Stabilizing C60 2 SETH DIFLEY, JACK SIMONS Department

  6. Abstract polymer models with general pair interactions Aldo Procacci

    E-Print Network [OSTI]

    Procacci, Aldo

    Abstract polymer models with general pair interactions Aldo Procacci Dep. Matem´atica-ICEx, UFMG (i.e. not necessarily hard core or repulsive). A concrete example is given in which polymers are r0 (possibly attractive), of the type 1/rd+ with > 0. 1. Introduction The abstract polymer gas is an important

  7. Transition maps between the 24 bases for a Leonard pair

    E-Print Network [OSTI]

    Nomura, Kazumasa

    2007-01-01

    Let $V$ denote a vector space with finite positive dimension. We consider a pair of linear transformations $A : V \\to V$ and $A^* : V \\to V$ that satisfy (i) and (ii) below: (i) There exists a basis for $V$ with respect to which the matrix representing $A$ is irreducible tridiagonal and the matrix representing $A^*$ is diagonal. (ii) There exists a basis for $V$ with respect to which the matrix representing $A^*$ is irreducible tridiagonal and the matrix representing $A$ is diagonal. We call such a pair a Leonard pair on $V$. In an earlier paper we described 24 special bases for $V$. One feature of these bases is that with respect to each of them the matrices that represent $A$ and $A^*$ are (i) diagonal and irreducible tridiagonal or (ii) irreducible tridiagonal and diagonal or (iii) lower bidiagonal and upper bidiagonal or (iv) upper bidiagonal and lower bidiagonal. For each ordered pair of bases among the 24, there exists a unique linear transformation from $V$ to $V$ that sends the first basis to the seco...

  8. Pair potential for FeHe N. Juslin *, K. Nordlund

    E-Print Network [OSTI]

    Nordlund, Kai

    formation and migration. Ab initio data for short range Fe­He dimer interaction is used to describe the high collision cascades have been extensively studied with MD simulations to determine primary damage formation shows that a pair potential is enough to describe simple He defects and migration of He in iron

  9. Creation and pinning of vortex-antivortex pairs 

    E-Print Network [OSTI]

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

    2006-01-01

    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. For film thickness =0.1 xi, kappa=2, and no pins, we find the film carries two V-AV pairs at steady state...

  10. Singlet Free Energies of a Static Quark-Antiquark Pair

    E-Print Network [OSTI]

    Konstantin Petrov

    2004-09-01

    We study the singlet part of the free energy of a static quark anti-quark pair at finite temperature in three flavor QCD with degenerate quark masses using $N_{\\tau}=4$ and 6 lattices with Asqtad staggered fermion action. We look at thermodynamics of the system around phase transition and study its scaling with lattice spacing and quark masses.

  11. Pair spectrometer hodoscope for Hall D at Jefferson Lab

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

    Barbosa, Fernando J.; Hutton, Charles L.; Sitnikov, Alexandre; Somov, Alexander S.; Somov, S.; Tolstukhin, Ivan

    2015-09-21

    We present the design of the pair spectrometer hodoscope fabricated at Jefferson Lab and installed in the experimental Hall D. The hodoscope consists of thin scintillator tiles; the light from each tile is collected using wave-length shifting fibers and detected using a Hamamatsu silicon photomultiplier. Light collection was measured using relativistic electrons produced in the tagger area of the experimental Hall B.

  12. Experimental Pair Trawling for Squid in New England

    E-Print Network [OSTI]

    warps in front of the net to frighten the fish. Midwater and bottom pair trawl- ing for various fish an area of good squid catches. During this trip, two tows were made after dark. All other tows with only one warp from each boat leading to two 20-fathom bri- dles (legs) on each side of the net

  13. BINARY STAR ORBITS. IV. ORBITS OF 18 SOUTHERN INTERFEROMETRIC PAIRS

    SciTech Connect (OSTI)

    Mason, Brian D.; Hartkopf, William I.; Tokovinin, Andrei E-mail: wih@usno.navy.mi

    2010-09-15

    First orbits are presented for 3 interferometric pairs and revised solutions for 15 others, based in part on first results from a recently initiated program of speckle interferometric observations of neglected southern binaries. Eight of these systems contain additional components, with multiplicity ranging up to 6.

  14. Banded Matrix Fraction Representation of Triangular Input Normal Pairs

    E-Print Network [OSTI]

    Banded Matrix Fraction Representation of Triangular Input Normal Pairs Andrew P. Mullhaupt #3 if and only if A is triangular and AA #3; + BB #3; = I n , where I n is the identity matrix. Input normal and A is a matrix fraction, A = M 1 N , where M and N are triangular matrices of low bandwidth. For single input

  15. The Dependency Pair Framework: Combining Techniques for Automated Termination Proofs #

    E-Print Network [OSTI]

    Ábrahám, Erika

    The Dependency Pair Framework: Combining Techniques for Automated Termination Proofs # J of the most powerful techniques for automated termination proofs of term rewrite systems. Up to now of new methods for termination analy­ sis. To demonstrate this, we present several new techniques within

  16. Scaling security in pairing-based protocols Michael Scott

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    Scaling security in pairing-based protocols Michael Scott School of Computing Dublin City potential advantage in smart-card and embedded applications ­ security can be scaled up while continuing been addressed by Koblitz and Menezes [18] and Granger, Page and Smart [15]. As will be seen our

  17. Collapsibility of Lung Volume by Paired Inspiratory and Expiratory CT

    E-Print Network [OSTI]

    Collapsibility of Lung Volume by Paired Inspiratory and Expiratory CT Scans: Correlations with Lung Function and Mean Lung Density Tsuneo Yamashiro, MD, Shin Matsuoka, MD, PhD, Brian J. Bartholmai, MD, Rau: To evaluate the relationship between measurements of lung volume (LV) on inspiratory/expiratory computed

  18. A PLANAR PARALLEL MANIPULATOR WITH HOLONOMIC HIGHER PAIRS: INVERSE KINEMATICS

    E-Print Network [OSTI]

    Hayes, John

    kinematic analysis. Very little literature on such planar mechanisms was found. The e ects of initialA PLANAR PARALLEL MANIPULATOR WITH HOLONOMIC HIGHER PAIRS: INVERSE KINEMATICS Matthew John D. HAYES of Mechanical Engineering 817 r. Sherbrooke O., Rm 454, Montreal, Quebec, H3A 2K6 Canada, Tel: (514) 398

  19. Bragg reflection waveguides as integrated sources of entangled photon pairs

    E-Print Network [OSTI]

    to design an electrically pumped entangled photon source. © 2012 Optical Society of America OCIS codes: 230Bragg reflection waveguides as integrated sources of entangled photon pairs Sergei V. Zhukovsky,1 of Physics and Institute for Optical Sciences, University of Toronto, 60 St. George Street, Toronto, Ontario

  20. Weakly Ionized Plasmas in Hypersonics: Fundamental Kinetics and Flight Applications

    SciTech Connect (OSTI)

    Macheret, Sergey

    2005-05-16

    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.

  1. Electron ionization of open/closed chain isocarbonic molecules relevant in plasma processing: Theoretical cross sections

    SciTech Connect (OSTI)

    Patel, Umang R., E-mail: umangpatel193@yahoo.ca [Gandhinagar Institute of Technology, Moti Bhoyan, Gandhinagar-382721, Gujarat (India); Sardar Patel University, Vallabh Vidyanagar-388120, Gujarat (India); Joshipura, K. N.; Pandya, Siddharth H. [Sardar Patel University, Vallabh Vidyanagar-388120, Gujarat (India)] [Sardar Patel University, Vallabh Vidyanagar-388120, Gujarat (India); Kothari, Harshit N. [Universal College of Engineering and Technology, Moti Bhoyan, Gandhinagar-382721, Gujarat (India)] [Universal College of Engineering and Technology, Moti Bhoyan, Gandhinagar-382721, Gujarat (India)

    2014-01-28

    In this paper, we report theoretical electron impact ionization cross sections from threshold to 2000 eV for isocarbonic open chain molecules C{sub 4}H{sub 6}, C{sub 4}H{sub 8}, C{sub 4}F{sub 6} including their isomers, and closed chain molecules c-C{sub 4}H{sub 8} and c-C{sub 4}F{sub 8}. Theoretical formalism employed presently, viz., Complex Scattering Potential-ionization contribution method has been used successfully for a variety of polyatomic molecules. The present ionization calculations are very important since results available for the studied targets are either scarce or none. Our work affords comparison of C{sub 4} containing hydrocarbon versus fluorocarbon molecules. Comparisons of the present ionization cross sections are made wherever possible, and new ionization data are also presented.

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

    E-Print Network [OSTI]

    Knevitt, Gillian; Power, Chris; Bolton, James

    2014-01-01

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

  3. International Journal of Mass Spectrometry 226 (2003) 135 Matrix-assisted laser desorption/ionization mass spectrometry

    E-Print Network [OSTI]

    2003-01-01

    , electrospray ionization; FAB, fast atom bom- bardment; Frc, fructose; FT, Fourier transform; Fuc, fucose; FWHM-assisted laser desorption/ ionization; Man, mannose; PAGE, polyacrylamide gel electropho- resis; PD, plasma

  4. Dosimetry for quantitative analysis of the effects of low-dose ionizing radiation in radiation therapy patients

    E-Print Network [OSTI]

    2006-01-01

    for studying low- dose radiation at the doses discussed hereof the Effects of Low-Dose Ionizing Radiation in Radiationof the Effects of Low-Dose Ionizing Radiation in Ra- diation

  5. Distinguishing LSP archetypes via gluino pair production at LHC13

    E-Print Network [OSTI]

    Altunkaynak, Baris; Barger, Vernon; Huang, Peisi

    2015-01-01

    The search for supersymmetry at Run 1 of LHC has resulted in gluino mass limits m(gluino)>~ 1.3 TeV for the case where m(gluino)RNS) and a higgsino-like LSP. In all three cases we expect heavy-to-very-heavy squarks as suggested by a decoupling solution to the SUSY flavor and CP problems and by the gravitino problem. For all cases, initial SUSY discovery would likely occur in the multi-b-jet + ETMISS channel. The CSB scenario would be revealed by the presence of highly-ionizing, terminating tracks from quasi-stable charginos. As further data accrue, the RNS scenario with ...

  6. Ionizing radiation predisposes non-malignant human mammary epithelial cells to undergo TGF beta-induced epithelial to mesenchymal transition

    E-Print Network [OSTI]

    2007-01-01

    Health Effects; the Low Dose Radiation Program of the DOElong-term, low-dose ionizing radiation exposure in humans.

  7. ASSESSMENT OF MARKER PROTEINS IDENTIFIED IN WHOLE CELL EXTRACTS FOR BACTERIAL SPECIATION USING LIQUID CHROMATOGRAPHY ELECTROSPRAY IONIZATION TANDEM MASS SPECTROMETRY

    SciTech Connect (OSTI)

    Kooken, Jennifer M.; Fox, Karen F.; Fox, Alvin; Wunschel, David S.

    2014-02-02

    ASSESSMENT OF MARKER PROTEINS IDENTIFIED IN WHOLE CELL EXTRACTS FOR BACTERIAL SPECIATION USING LIQUID CHROMATOGRAPHY ELECTROSPRAY IONIZATION TANDEM MASS SPECTROMETRY

  8. Ionization Driven Fragmentation of Gas Outflows Responsible for FeLoBALs in Quasars

    E-Print Network [OSTI]

    Bautista, Manuel A

    2010-01-01

    We show that time variations in the UV ionizing continuum of quasars, on scales of $\\sim$1 year, affect the dynamic structure of the plasmas responsible for low ionization broad absorption lines. Variations of the ionizing continuum produce non-equilibrium photoionization conditions over a significant fraction of the absorbing clouds and supersonically moving ionization fronts. When the flux drops the contraction of the ionized region drives a supersonic cooling front towards the radiation source and a rarefaction wave in the opposite direction. The pressure imbalance is compensated by an increased speed of the cool gas relative to the front. When the flux recovers the cool gas is re-ionized and re-heated by a supersonic ionization front traveling away from the radiation source and a forward shock is created. The reheated clouds equilibrate to a temperature of $\\sim 10^4$ K and are observed to have different radial velocities than the main cloud. Such fragmentation seems consistent with the multicomponent str...

  9. Pair Instability Supernovae of Very Massive Population III Stars

    E-Print Network [OSTI]

    Chen, Ke-Jung; Woosley, Stan; Almgren, Ann; Whalen, Daniel

    2014-01-01

    Numerical studies of primordial star formation suggest that the first stars in the universe may have been very massive. Stellar models indicate that non-rotating Population III stars with initial masses of 140-260 Msun die as highly energetic pair-instability supernovae. We present new two-dimensional simulations of primordial pair-instability supernovae done with the CASTRO code. Our simulations begin at earlier times than previous multidimensional models, at the onset of core collapse, to capture any dynamical instabilities that may be seeded by collapse and explosive burning. Such instabilities could enhance explosive yields by mixing hot ash with fuel, thereby accelerating nuclear burning, and affect the spectra of the supernova by dredging up heavy elements from greater depths in the star at early times. Our grid of models includes both blue supergiants and red supergiants over the range in progenitor mass expected for these events. We find that fluid instabilities driven by oxygen and helium burning ari...

  10. Higgs pair production at the High Luminosity LHC

    E-Print Network [OSTI]

    CMS Collaboration

    2015-01-01

    Studies of the Higgs boson pair production and decays into $bb\\gamma\\gamma$, $bb\\tau\\tau$, and $bb\\mathrm{W}\\mathrm{W}$ final states are presented. The studies are performed assuming the operational conditions of the High-Luminosity LHC, with an integrated luminosity of 3000~$\\mathrm{fb}^{-1}$, and the upgraded CMS experiment. Combining the studies of $bb\\gamma\\gamma$ and $bb\\tau\\tau$ final states, the expected significance for Higgs boson pair production is 1.9 standard deviation. The resulting expected uncertainty in the signal yield is $54\\%$. The benefits of the CMS Phase-II upgrade, to meet the challenges presented by the high luminosity environment, are emphasized.

  11. Observation of ?c1 Decays into Vector Meson Pairs ??, ?? and, ??

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

    Ablikim, M.; Achasov, M. N.; An, L.; An, Q.; An, Z. H.; Bai, J. Z.; Baldini, R.; Ban, Y.; Becker, J.; Berger, N.; et al

    2011-08-22

    Using (106±4)×10? ?(3686) events accumulated with the BESIII detector at the BEPCII e?e? collider, we present the first measurement of decays of ?c1 to vector meson pairs ??, ??, and ??. The branching fractions are measured to be (4.4±0.3±0.5)×10??, (6.0±0.3±0.7)×10??, and (2.2±0.6±0.2)×10??, for ?c1 ???, ??, and ??, respectively, which indicates that the hadron helicity selection rule is significantly violated in ?cJ decays. In addition, the measurement of ?cJ??? provides the first indication of the rate of doubly OZI-suppressed ?cJ decay. Finally, we present improved measurements for the branching fractions of ?c0 and ?c2 to vector meson pairs.

  12. The Phoenix survey: the pairing fraction of faint radio sources

    E-Print Network [OSTI]

    A. Georgakakis; B. Mobasher; L. Cram; A. Hopkins

    1999-10-07

    The significance of tidal interactions in the evolution of the faint radio population (sub-mJy) is studied using a deep and homogeneous radio survey (1.4 GHz), covering an area of 3.14 deg$^2$ and complete to a flux density of 0.4 mJy. Optical photometric and spectroscopic data are also available for this sample. A statistical approach is employed to identify candidate physical associations between radio sources and optically selected `field' galaxies. We find an excess of close pairs around optically identified faint radio sources, albeit at a low significance level, implying that the pairing fraction of the sub-mJy radio sources is similar to that of `field' galaxies (at the same magnitude limit) but higher than that of local galaxies.

  13. Metal ion complexation by ionizable crown ethers. Final report, January 1, 1988--June 30, 1994

    SciTech Connect (OSTI)

    Bartsch, R.A.

    1994-12-31

    During the report period a variety of new lipophilic ionizable crown ethers with pendent proton-ionizable groups has been synthesized. The ligands possess one or more ionizable group (carboxylic acid, phosphonic acid monoethyl ester, para-nitrophenol, phosphonic acid) attached to crown ether, monoazacrown ether or diazacrown ether frameworks. These novel chelating agents have either pendent or inward-facing proton-ionizable groups. Such lipophilic proton-ionizable crown ethers are designed for use in multiphase metal ion separations (solvent extraction, liquid membrane transport). In addition a series of proton-ionizable crown ethers without lipophilic groups was prepared to study how structural variations within the ligand influence metal ion complexation in homogeneous media as assessed by NMR spectroscopy or titration calorimetry. A third class of new metal ion-complexing agents is a series of lipophilic acyclic polyether dicarboxylic acids. Competitive solvent extractions of alkali metal and alkaline earth cations and of the mixed species have been conducted to reveal the influence of ring size, nature and attachment site of the lipophilic group, sidearm length, and proton-ionizable group identity and location upon the selectivity and efficiency of metal ion complexation. In addition to such studies of structural variation within the lipophilic proton-ionizable crown ether, the effect of changing the organic solvent and variation of the stripping conditions have been assessed. The influence of structural variations within lipophilic acyclic polyether dicarboxylic acids upon competitive solvent extraction of alkaline earth cations has been probed. Also a new chromogenic, di-ionizable crown ether with extremely high selectivity for Hg{sup 2+} has been discovered.

  14. Proton-neutron pairing energies in N=Z nuclei at finite temperature

    E-Print Network [OSTI]

    K. Kaneko; M. Hasegawa

    2005-08-27

    Thermal behavior of isoscalar and isovector proton-neutron (pn) pairing energies at finite temperature are investigated by the shell model calculations. These pn pairing energies can be estimated by double differences of "thermal" energies which are extended from the double differences of binding energies as the indicators of pn pairing energies at zero temperature. We found that the delicate balance between isoscalar and isovector pn pairing energies at zero temperature disappears at finite temperature. When temperature rises, while the isovector pn pairing energy decreases, the isoscalar pn pairing energy rather increases. We discuss also the symmetry energy at finite temperature.

  15. Fourier Transform Pairs The Fourier transform transforms a function of

    E-Print Network [OSTI]

    Masci, Frank

    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

  16. Calculations of pair production by Monte Carlo methods

    SciTech Connect (OSTI)

    Bottcher, C.; Strayer, M.R.

    1991-01-01

    We describe some of the technical design issues associated with the production of particle-antiparticle pairs in very large accelerators. To answer these questions requires extensive calculation of Feynman diagrams, in effect multi-dimensional integrals, which we evaluate by Monte Carlo methods on a variety of supercomputers. We present some portable algorithms for generating random numbers on vector and parallel architecture machines. 12 refs., 14 figs.

  17. Brane tunneling and virtual brane-antibrane pairs

    E-Print Network [OSTI]

    Adam R. Brown

    2007-09-24

    We survey barrier penetration by quantum tunneling for four cases: nonrelativistic point particles, scalar fields, relativistic point particles, and DBI branes. We examine two novel features that arise for DBI brane tunneling: the rate can sometimes increase as the barrier gets higher; and the instanton "wrinkles". We show that these features can be understood as the effect of the quantum sea of virtual brane-antibrane pairs. This sea exponentially augments the decay rate, with possible cosmological consequences.

  18. Sedimentation of pairs of hydrodynamically interacting semiflexible filaments

    E-Print Network [OSTI]

    Isaac Llopis; Ignacio Pagonabarraga; Marco Cosentino Lagomarsino; Christopher P. Lowe

    2007-10-08

    We describe the effect of hydrodynamic interactions in the sedimentation of a pair of inextensible semiflexible filaments under a uniform constant force at low Reynolds numbers. We have analyzed the different regimes and the morphology of such polymers in simple geometries, which allow us to highlight the peculiarities of the interplay between elastic and hydrodynamic stresses. Cooperative and symmetry breaking effects associated to the geometry of the fibers gives rise to characteristic motion which give them distinct properties from rigid and elastic filaments.

  19. Double Pair Production by Ultra High Energy Cosmic Ray Photons

    E-Print Network [OSTI]

    S. V. Demidov; O. E. Kalashev

    2008-12-22

    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.

  20. The origin of the ionization of the diffuse interstellar medium in spiral galaxies. II. Modelling the distribution of ionizing radiation in NGC 157

    E-Print Network [OSTI]

    A. Zurita; J. E. Beckman; M. Rozas; S. Ryder

    2002-03-15

    In this paper we make a quantitative study of the hypothesis that the diffuse H-alpha emitted from the discs of spiral galaxies owes its origin to the ionizing photons escaping from HII regions. We use the H-alpha measurements of the complete set of HII regions in the spiral NGC 157, for which an HI density map was available, to derive a family of models which predict the ionizing photon distribution in the disc of this galaxy. The predicted diffuse H-alpha surface brightness distributions from our models were compared with the observed distributions showing that, in general terms, the hypothesis of density bounding for the HII regions allows us to predict well the spatial distribution of the diffuse ionized gas. In the model yielding the best fit to the data, the regions of lower luminosity lose a constant fraction of their ionizing flux to their surroundings, while for HII region luminosities above a specific transition value the ionizing escape fraction is a rising function of the Ha luminosity.

  1. Equilibrium cluster fluids: Pair interactions via inverse design

    E-Print Network [OSTI]

    Ryan B. Jadrich; Jonathan A. Bollinger; Beth A. Lindquist; Thomas M. Truskett

    2015-09-14

    Inverse methods of statistical mechanics are becoming productive tools in the design of materials with specific microstructures or properties. While initial studies have focused on solid-state design targets (e.g, assembly of colloidal superlattices), one can alternatively design fluid states with desired morphologies. This work addresses the latter and demonstrates how a simple iterative Boltzmann inversion strategy can be used to determine the isotropic pair potential that reproduces the radial distribution function of a fluid of amorphous clusters with prescribed size. The inverse designed pair potential of this "ideal" cluster fluid, with its broad attractive well and narrow repulsive barrier at larger separations, is qualitatively different from the so-called SALR form most commonly associated with equilibrium cluster formation in colloids, which features short-range attractive (SA) and long-range repulsive (LR) contributions. These differences reflect alternative mechanisms for promoting cluster formation with an isotropic pair potential, and they in turn produce structured fluids with qualitatively different static and dynamic properties. Specifically, equilibrium simulations show that the amorphous clusters resulting from the inverse designed potentials display more uniformity in size and shape, and they also show greater spatial and temporal resolution than those resulting from SALR interactions.

  2. Physics of base-pairing dynamics in DNA

    E-Print Network [OSTI]

    Manoel Manghi; Nicolas Destainville

    2015-10-19

    As a key molecule of Life, Deoxyribonucleic acid (DNA) is the focus of numbers of investigations with the help of biological, chemical and physical techniques. From a physical point of view, both experimental and theoretical works have brought quantitative insights into DNA base-pairing dynamics that we review in this Report, putting emphasis on theoretical developments. We discuss the dynamics at the base-pair scale and its pivotal coupling with the polymer one, with a polymerization index running from a few nucleotides to tens of kilo-bases. This includes opening and closure of short hairpins and oligomers as well as zipping and unwinding of long macromolecules. We review how different physical mechanisms are either used by Nature or utilized in biotechnological processes to separate the two intertwined DNA strands, by insisting on quantitative results. They go from thermally-assisted denaturation bubble nucleation to force- or torque- driven mechanisms. We show that the helical character of the molecule, possibly supercoiled, can play a key role in many denaturation and renaturation processes. We categorize the mechanisms according to the relative timescales associated with base-pairing and chain degrees of freedom such as bending and torsional elastic ones. In some specific situations, these chain degrees of freedom can be integrated out, and the quasi- static approximation is valid. The complex dynamics then reduces to the diffusion in a low-dimensional free-energy landscape. In contrast, some important cases of experimental interest necessarily appeal to far-from-equilibrium statistical mechanics and hydrodynamics.

  3. HBT interferometry with quantum transport of the interfering pair

    E-Print Network [OSTI]

    Yu, Li-Li; Wong, Cheuk-Yin

    2008-01-01

    In the late stage of the evolution of a pion system in high-energy heavy-ion collisions when pions undergo multiple scatterings, the quantum transport of the interfering pair of identical pions plays an important role in determining the characteristics of the Hanbury-Brown-Twiss (HBT) interference. We study the quantum transport of the interfering pair using the path-integral method, in which the evolution of the bulk matter is described by relativistic hydrodynamics while the paths of the two interfering pions by test particles following the fluid positions and velocity fields. We investigate in addition the effects of secondary pion sources from particle decays, for nuclear collisions at AGS and RHIC energies. We find that quantum transport of the interfering pair leads to HBT radii close to those for the chemical freeze-out configuration. Particle decays however lead to HBT radii greater than those for the chemical freeze-out configuration. As a consequence, the combined effects give rise to HBT radii betw...

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

    SciTech Connect (OSTI)

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

    2014-12-01

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

  5. Isotope fractionation in surface ionization ion source of alkaline-earth iodides

    SciTech Connect (OSTI)

    Suzuki, T.; Kanzaki, C.; Nomura, M.; Fujii, Y.

    2012-02-15

    The relationship between the isotope fractionation of alkaline-earth elements in the surface ionization ion source and the evaporation filament current, i.e., filament temperature, was studied. It was confirmed that the isotope fractionation depends on the evaporation filament temperature; the isotope fractionation in the case of higher temperature of filament becomes larger. The ionization and evaporation process in the surface ionization ion source was discussed, and it was concluded that the isotope fractionation is suppressed by setting at the lower temperature of evaporation filament because the dissociations are inhibited on the evaporation filament.

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

    E-Print Network [OSTI]

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

    2011-01-01

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

  7. Effects of ionization distribution on plasma beam focusing characteristics in Hall thrusters

    SciTech Connect (OSTI)

    Ning Zhongxi; Liu Hui; Yu Daren [Plasma Propulsion Laboratory, Harbin Institute of Technology, Harbin 150001 (China); Zhou Zhongxiang [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China)

    2011-11-28

    The relationship between ionization distribution and divergence of plasma beam in a Hall thruster is investigated using spectrum and probe methods. Experimental results indicate that the shift of ionization region towards the exit of channel causes the reduction of accelerating field and the enhancement of electron thermal pressure effect, which result in further deviation of equipotential lines to magnetic field lines and further increase in divergence of plasma beam. It is, therefore, suggested that to put the ionization region deep inside the channel and separate it from the acceleration region at the design, and development stage is helpful to improve the plasma beam focusing characteristics of a Hall thruster.

  8. The Role of Partial Ionization Effects in the Chromosphere

    E-Print Network [OSTI]

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

    2015-01-01

    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...

  9. IONIZING RADIATION FROM z = 4-10 GALAXIES

    SciTech Connect (OSTI)

    Razoumov, Alexei O. [Institute for Computational Astrophysics, Department of Astronomy and Physics, Saint Mary's University, Halifax, NS, B3H 3C3 (Canada); Sommer-Larsen, Jesper, E-mail: razoumov@ap.smu.c, E-mail: jslarsen@astro.ku.d [Excellence Cluster Universe, Technische Universitaet Muenchen, Boltzmannstrasse 2, D-85748 Garching (Germany)

    2010-02-20

    We compute the escape of ionizing radiation from galaxies in the redshift interval z = 4-10, i.e., during and after the epoch of reionization, using a high-resolution set of galaxies, formed in fully cosmological simulations. The simulations invoke early, energetic feedback, and the galaxies evolve into a realistic population at z = 0. Our galaxies cover nearly four orders of magnitude in masses (10{sup 7.8}-10{sup 11.5} M{sub sun}) and more than five orders in star formation rates (10{sup -3.5}-10{sup 1.7} M{sub sun} yr{sup -1}), and we include an approximate treatment of dust absorption. We show that the source-averaged Lyman limit escape fraction at z = 10.4 is close to 80% declining monotonically with time as more massive objects build up at lower redshifts. Although the amount of dust absorption is uncertain to 1-1.5 dex, it is tightly correlated with metallicity; we find that dust is unlikely to significantly impact the observed UV output. These results support reionization by stellar radiation from low-luminosity dwarf galaxies and are also compatible with Lyman continuum observations and theoretical predictions at z {approx} 3-4.

  10. RG-Improved Predictions for Top-Quark Pair Production at

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    RG-Improved Predictions for Top-Quark Pair Production at Hadron Colliders Matthias Neubert Johannes Threshold resummation for Higgs production Threshold resummation for top-quark pair production Valentin

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

    E-Print Network [OSTI]

    Broekhuizen, Keith Edward, 1974-

    2002-01-01

    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 ...

  12. First Born calculations of the single and double ionization of H- by bare-ion projectiles 

    E-Print Network [OSTI]

    Saunders, Anna Windsor

    1996-01-01

    Finite basis diagonalizations were used to calculate the He and H-ground state energies and the He and H-ground state single and double ionization cross sections were calculated using the first Bom approximation at several ...

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

    E-Print Network [OSTI]

    Campo, Karen Kay

    1996-01-01

    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...

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

    E-Print Network [OSTI]

    Mann, John Clifford

    2006-10-30

    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 ...

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

    E-Print Network [OSTI]

    Davidson, Matthew Allen

    2011-01-01

    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, ...

  16. Reconstruction of ionization probabilities from spatially averaged data in N dimensions 

    E-Print Network [OSTI]

    Stroahaber, James; Kolomenskii, A; Schuessler, Hans

    2010-07-06

    . In three dimensions, ionization probabilities of Xe were successfully recovered with MPE from simulated (using the Ammosov-Delone-Krainov tunneling theory) ion yields. Finally, we tested our approach with intensity-resolved benzene-ion yields, which show a...

  17. Revisiting benzene cluster cations for the chemical ionization of dimethyl sulfide and select volatile organic compounds

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

    Kim, M. J.; Zoerb, M. C.; Campbell, N. R.; Zimmermann, K. J.; Blomquist, B. W.; Huebert, B. J.; Bertram, T. H.

    2015-10-01

    Benzene cluster cations were revisited as a sensitive and selective reagent ion for the chemical ionization of dimethyl sulfide (DMS) and a select group of volatile organic compounds (VOCs). Laboratory characterization was performed using both a new set of compounds (i.e. DMS, ?-caryophyllene) as well as previously studied VOCs (i.e., isoprene, ?-pinene). Using a field deployable chemical ionization time-of-flight mass spectrometer (CI-ToFMS), benzene cluster cations demonstrated high sensitivity (> 1 ncps ppt?1) to DMS, isoprene, and ?-pinene standards. Parallel measurements conducted using a chemical-ionization quadrupole mass spectrometer, with a weaker electric field, demonstrated that ion-molecule reactions likely proceed through amore »combination of ligand-switching and direct charge transfer mechanisms. Laboratory tests suggest that benzene cluster cations may be suitable for the selective ionization of sesquiterpenes, where minimal fragmentation (R2=0.80) over a wide range of sampling conditions.« less

  18. Interaction between overlapping photo-ionized doubly excited resonances series for He atom

    E-Print Network [OSTI]

    Chang, Tu-nan

    Interaction between overlapping photo-ionized doubly excited resonances series for He atom T. N, to characterize correctly the multi-photon processes, it is critical to compile the accu- rate theoretical

  19. OPTICAL SPECTROSCOPY OF H? FILAMENTS IN COOL CORE CLUSTERS: KINEMATICS, REDDENING, AND SOURCES OF IONIZATION

    E-Print Network [OSTI]

    McDonald, Michael A.

    We have obtained deep, high spatial and spectral resolution, long-slit spectra of the H? nebulae in the cool cores of nine galaxy clusters. This sample provides a wealth of information on the ionization state, kinematics, ...

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

    E-Print Network [OSTI]

    Wei, Xiaona

    1996-01-01

    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...

  1. Ionization of Water Clusters is Mediated by Exciton Energy Transfer from Argon Clusters

    E-Print Network [OSTI]

    Golan, Amir

    2013-01-01

    with Ionization in Water Tetramers. Phys. Chem. Chem. Phys.PIE) curves of water tetramer, (H 2 O) 4+ (red filled (30step size)) and protonated tetramer, (H 2 O) 4 H + (black

  2. Phase-space structures and ionization dynamics of the hydrogen atom in elliptically polarized microwaves

    SciTech Connect (OSTI)

    Shchekinova, E.; Uzer, T. [Center for Nonlinear Science, School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430 (United States); Chandre, C. [Centre de Physique Theorique-CNRS, Luminy, Case 907, 13288 Marseille Cedex 09 (France)

    2006-10-15

    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 Poincare surfaces of section, impractical. We analyze the phase-space dynamics using the 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.

  3. CNT-based gas ionizers with integrated MEMS gate for portable mass spectrometry applications

    E-Print Network [OSTI]

    Velasquez-Garcia, Luis Fernando

    We report the fabrication and experimental characterization of a novel low-cost carbon nanotube (CNT)-based electron impact ionizer (EII) with integrated gate for portable mass spectrometry applications. The device achieves ...

  4. Intense Field Multiphoton Ionization via Complex Dressed States: Application to the H Atom

    E-Print Network [OSTI]

    Chu, Shih-I; Reinhardt, William P.

    1977-11-07

    Extension of Floquet theory to include continuum as well as bound atomic states yields a practical technique for computation of multiphoton ionization rates in the region where rms field strengths approach the strength of the internal atomic fields....

  5. Isomeric differentiation of polycyclic aromatic hydrocarbons using silver nitrate reactive desorption electrospray ionization

    E-Print Network [OSTI]

    Zare, Richard N.

    Isomeric differentiation of polycyclic aromatic hydrocarbons using silver nitrate reactive hydrocarbons (PAHs) are nonpolar and difficult to detect by desorption electrospray ionization. We present. Polycyclic aromatic hydrocarbons (PAHs) are one of the most prevalent forms of aquatic environmental

  6. Ionizing radiation post-curing of objects produced by stereolithography and other methods

    DOE Patents [OSTI]

    Howell, David H. (Knoxville, TN); Eberle, Claude C. (Knoxville, TN); Janke, Christopher J. (Oliver Springs, TN)

    2000-01-01

    An object comprised of a curable material and formed by stereolithography or another three-dimensional prototyping method, in which the object has undergone initial curing, is subjected to post-curing by ionizing radiation, such as an electron beam having a predetermined beam output energy, which is applied in a predetermined dosage and at a predetermined dose rate. The post-cured object exhibits a property profile which is superior to that which existed prior to the ionizing radiation post-curing.

  7. A NEW CALCULATION OF THE IONIZING BACKGROUND SPECTRUM AND THE EFFECTS OF He II REIONIZATION

    SciTech Connect (OSTI)

    Faucher-Giguere, Claude-Andre; Lidz, Adam; Zaldarriaga, Matias; Hernquist, Lars, E-mail: cgiguere@cfa.harvard.ed [Department of Astronomy, Harvard University, Cambridge, MA 02138 (United States)

    2009-10-01

    The ionizing background determines the ionization balance and the thermodynamics of the cosmic gas. It is therefore a fundamental ingredient to theoretical and empirical studies of both the intergalactic medium (IGM) and galaxy formation. We present here a new calculation of its spectrum that satisfies the empirical constraints we recently obtained by combining state-of-the-art luminosity functions and intergalactic opacity measurements. In our preferred model, star-forming galaxies and quasars each contribute substantially to the H I ionizing field at z < 3, with galaxies rapidly overtaking quasars at higher redshifts as quasars become rarer. In addition to our fiducial model, we explore the physical dependences of the calculated background and clarify how recombination emission contributes to the ionization rates. We find that recombinations do not simply boost the ionization rates by the number of re-emitted ionizing photons as many of these rapidly redshift below the ionization edges and have a distribution of energies. A simple analytic model that captures the main effects seen in our numerical radiative transfer calculations is given. Finally, we discuss the effects of He II reionization by quasars on both the spectrum of the ionizing background and on the thermal history of the IGM. In regions that have yet to be reionized, the spectrum is expected to be almost completely suppressed immediately above 54.4 eV, while a background of higher energy ({approx}>0.5 keV) photons permeates the entire universe owing to the frequency dependence of the photoionization cross section. We provide an analytical model of the heat input during He II reionization and its effects on the temperature-density relation.

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

    SciTech Connect (OSTI)

    Bailey, Catherine N.

    2010-01-01

    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.

  9. NON-BIPARTITE PAIRS OF 3-CONNECTED GRAPHS ARE HIGHLY RAMSEY-INFINITE

    E-Print Network [OSTI]

    Siggers, Mark H.

    NON-BIPARTITE PAIRS OF 3-CONNECTED GRAPHS ARE HIGHLY RAMSEY-INFINITE MARK SIGGERS ABSTRACT. A pair of graphs (Hb,Hr) is highly Ramsey-infinite if there is some constant c such that for large enough n. We show that a pair of 3-connected graphs is highly Ramsey-infinite if and only if at least one

  10. $J$-pairing Interactions of Fermions in a Single-$j$ Shell

    E-Print Network [OSTI]

    A. Arima

    2004-05-26

    In this talk I shall introduce our recent works on general pairing interactions and pair truncation approximations for fermions in a single-j shell, including the spin zero dominance, features of eigenvalues of fermion systems in a single-j shell interacting by a $J-$pairing interaction.

  11. Job Title Executive Director Employer/ Agency PAIR: Partnership for the Advancement & Immersion of Refugees

    E-Print Network [OSTI]

    Azevedo, Ricardo

    of Refugees Job Description Houston-based Partnership for the Advancement & Immersion of Refugees (PAIR) (www volunteers serving more than 200 refugees per year, PAIR empowers refugee youth to reach their full potential in the community to foster an understanding of the needs of young refugees and the role of PAIR's programs

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

    DOE Patents [OSTI]

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

    2009-05-12

    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.

  13. Hydrologic calibration of paired watersheds using a MOSUM approach

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

    Ssegane, H.; Amatya, D. M.; Muwamba, A.; Chescheir, G. M.; Appelboom, T.; Tollner, E. W.; Nettles, J. E.; Youssef, M. A.; Birgand, F.; Skaggs, R. W.

    2015-01-09

    Paired watershed studies have historically been used to quantify hydrologic effects of land use and management practices by concurrently monitoring two neighboring watersheds (a control and a treatment) during the calibration (pre-treatment) and post-treatment periods. This study characterizes seasonal water table and flow response to rainfall during the calibration period and tests a change detection technique of moving sums of recursive residuals (MOSUM) to select calibration periods for each control-treatment watershed pair when the regression coefficients for daily water table elevation (WTE) were most stable to reduce regression model uncertainty. The control and treatment watersheds included 1–3 year intensively managedmore »loblolly pine (Pinus taeda L.) with natural understory, same age loblolly pine intercropped with switchgrass (Panicum virgatum), 14–15 year thinned loblolly pine with natural understory (control), and switchgrass only. Although monitoring during the calibration period spanned 2009 to 2012, silvicultural operational practices that occurred during this period such as harvesting of existing stand and site preparation for pine and switchgrass establishment may have acted as external factors, potentially shifting hydrologic calibration relationships between control and treatment watersheds. Results indicated that MOSUM was able to detect significant changes in regression parameters for WTE due to silvicultural operations. This approach also minimized uncertainty of calibration relationships which could otherwise mask marginal treatment effects. All calibration relationships developed using this MOSUM method were quantifiable, strong, and consistent with Nash–Sutcliffe Efficiency (NSE) greater than 0.97 for WTE and NSE greater than 0.92 for daily flow, indicating its applicability for choosing calibration periods of paired watershed studies.« less

  14. Radiative emission of neutrino pair free of quantum electrodynamic backgrounds

    E-Print Network [OSTI]

    M. Yoshimura; N. Sasao; M. Tanaka

    2015-01-23

    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.

  15. Photoproduction of electron-positron pairs in bent single crystals

    E-Print Network [OSTI]

    Chesnokov, Yu A; Bolognini, D; Hasan, S; Prest, M; Vallazza, E

    2010-01-01

    The process of photoproduction of electron-positron pairs in bent single crystals is considered in this paper. In particular, it is shown that the probability of the process for gamma-quanta with energies from 100 GeV on is significantly higher than the one in an amorphous medium. A possible scenario for the experimental validation of the process is discussed and the positive features of the photoproduction in bent crystals compared to straight ones are underlined from the point of view of possible applications.

  16. Infinitely many pairs of primes $p$ and $p+2$

    E-Print Network [OSTI]

    Guangchang Dong

    2015-03-20

    When $p$ and $p+2$ are primes, such as $3,5; 5,7; 11,13; 17,19; ...$. We call them pairs of prime twins. In this paper we use sieve method (Liu sieve) to construct the weak solution (i.e. formal solution) of prime twins. Then we use auxiliary special 4 sieve problem and its biological model to prove that weak equals classical, i.e. the weak solution is a classical one, hence the numbers of prime twins are infinite.

  17. Building Projected Entangled Pair States with a Local Gauge Symmetry

    E-Print Network [OSTI]

    Erez Zohar; Michele Burrello

    2015-11-26

    Tensor network states, and in particular projected entangled pair states (PEPS), suggest an innovative approach for the study of lattice gauge theories, both from a pure theoretic point of view, and as a tool for the analysis of the recent proposals for quantum simulations of lattice gauge theories. In this paper we present a framework for describing locally gauge invariant states on lattices using PEPS. The PEPS constructed hereby shall include both bosonic and fermionic states, suitable for all combinations of matter and gauge fields in lattice gauge theories defined by either finite or compact Lie groups.

  18. Automated Complexity Analysis Based on the Dependency Pair Method

    E-Print Network [OSTI]

    Hirokawa, Nao

    2011-01-01

    This article is concerned with automated complexity analysis of term rewrite systems (TRSs for short). Since these systems underlie much of declarative programming, time complexity of functions defined by TRSs is of particular interest. Among other results, we present a variant of the dependency pair method for analysing runtime complexities of term rewrite systems automatically. The established results significantly extent previously known techniques: we give examples of TRSs subject to our methods that could previously not been analysed automatically. Furthermore, the techniques have been implemented in the Tyrolean Complexity Tool. We provide ample numerical data for assessing the viability of the method.

  19. Lepton-pair production in nuclear collisions - past, present, future

    E-Print Network [OSTI]

    H. J. Specht

    2007-10-29

    The key results on lepton-pair production in ultra-relativistic nuclear collisions are shortly reviewed, starting at the roots of pp collisions in the seventies, and ending at the perspectives of the colliders RHIC and LHC. The presence is dominated by the recent precision results from NA60 at the CERN SPS, culminating in the first measurement of the in-medium rho spectral function and the transverse flow of the associated thermal radiation. The seeming cut-off of the flow above the rho may well be the first direct hint for thermal radiation of partonic origin in nuclear collisions. The major milestones in the theoretical developments are also covered.

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

    E-Print Network [OSTI]

    Bradfield, Meredith

    2013-01-01

    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,

  1. Hartree-Fock-Bogoliubov solution of the pairing Hamiltonian in finite nuclei

    E-Print Network [OSTI]

    Dobaczewski, J

    2012-01-01

    We present an overview of the Hartree-Fock-Bogoliubov (HFB) theory of nucleonic superfluidity for finite nuclei. After introducing basic concepts related to pairing correlations, we show how the correlated pairs are incorporated into the HFB wave function. Thereafter, we present derivation and structure of the HFB equations within the superfluid nuclear density functional formalism and discuss several aspects of the theory, including the unitarity of the Bogoliubov transformation in truncated single-particle and quasiparticle spaces, form of the pairing functional, structure of the HFB continuum, regularization and renormalization of pairing fields, and treatment of pairing in systems with odd particle numbers.

  2. Pair production of color-octet scalars at the LHC

    SciTech Connect (OSTI)

    Idilbi, Ahmad [Department of Physics, Duke University, Durham, North Carolina 27708 (United States); Departamento de Fisica Teorica II, Universidad Complutense de Madrid, 28040 Madrid (Spain); Kim, Chul [Department of Physics, Duke University, Durham, North Carolina 27708 (United States); Theory Division, Department of Physics, CERN, CH-1211, Geneva 23 (Switzerland); Mehen, Thomas [Department of Physics, Duke University, Durham, North Carolina 27708 (United States)

    2010-10-01

    Heavy colored scalar particles, which exist in many models of new physics, can be pair produced at the LHC via gluon-gluon fusion and possibly form quarkoniumlike bound states. If the scalars are also charged under the electroweak gauge group, these bound states can then decay into electroweak bosons. This yields a resonant cross section for final states such as {gamma}{gamma} that can exceed standard model backgrounds. This paper studies this process in the Manohar-Wise model of color-octet scalars (COS). Important threshold logarithms and final state Coulomb-like QCD interactions are resummed using effective field theory. We compute the resummed cross section for gluon-gluon fusion to COS pairs at the LHC as well as the resonant cross section for octetonium decaying to {gamma}{gamma}. The latter cross section exceeds the standard model diphoton cross section when the COS mass is less than 500 (350) GeV for {radical}(s)=14(7) TeV. Nonobservation of resonances below these energies can significantly improve existing bounds on COS masses.

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

    SciTech Connect (OSTI)

    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)

    2013-11-10

    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.

  4. Creation of Electron Spinless Pairs in the Superconductivity

    E-Print Network [OSTI]

    V. N. Minasyan

    2009-03-28

    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.

  5. Top quark pair production and top quark properties at CDF

    E-Print Network [OSTI]

    Chang-Seong Moon

    2014-11-01

    We present the most recent measurements of top quark pairs production and top quark properties in proton-antiproton collisions with center-of-mass energy of 1.96 TeV using CDF II detector at the Tevatron. The combination of top pair production cross section measurements and the direct measurement of top quark width are reported. The test of Standard Model predictions for top quark decaying into $b$-quarks, performed by measuring the ratio $R$ between the top quark branching fraction to $b$-quark and the branching fraction to any type of down quark is shown. The extraction of the CKM matrix element $|V_{tb}|$ from the ratio $R$ is discussed. We also present the latest measurements on the forward-backward asymmetry ($A_{FB}$) in top anti-top quark production. With the full CDF Run II data set, the measurements are performed in top anti-top decaying to final states that contain one or two charged leptons (electrons or muons). In addition, we combine the results of the leptonic forward-backward asymmetry in $t\\bar t$ system between the two final states. All the results show deviations from the next-to-leading order (NLO) standard model (SM) calculation.

  6. Pair instability supernovae of very massive population III stars

    SciTech Connect (OSTI)

    Chen, Ke-Jung; Woosley, Stan [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Heger, Alexander [Monash Centre for Astrophysics, Monash University, Victoria 3800 (Australia); Almgren, Ann [Center for Computational Sciences and Engineering, Lawrence Berkeley National Lab, Berkeley, CA 94720 (United States); Whalen, Daniel J., E-mail: kchen@ucolick.org [T-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2014-09-01

    Numerical studies of primordial star formation suggest that the first stars in the universe may have been very massive. Stellar models indicate that non-rotating Population III stars with initial masses of 140-260 M {sub ?} die as highly energetic pair-instability supernovae. We present new two-dimensional simulations of primordial pair-instability supernovae done with the CASTRO code. Our simulations begin at earlier times than previous multidimensional models, at the onset of core contraction, to capture any dynamical instabilities that may be seeded by core contraction and explosive burning. Such instabilities could enhance explosive yields by mixing hot ash with fuel, thereby accelerating nuclear burning, and affect the spectra of the supernova by dredging up heavy elements from greater depths in the star at early times. Our grid of models includes both blue supergiants and red supergiants over the range in progenitor mass expected for these events. We find that fluid instabilities driven by oxygen and helium burning arise at the upper and lower boundaries of the oxygen shell ?20-100 s after core bounce. Instabilities driven by burning freeze out after the SN shock exits the helium core. As the shock later propagates through the hydrogen envelope, a strong reverse shock forms that drives the growth of Rayleigh-Taylor instabilities. In red supergiant progenitors, the amplitudes of these instabilities are sufficient to mix the supernova ejecta.

  7. Search for pair production of second generation scalar leptoquarks

    SciTech Connect (OSTI)

    Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Aguilo, E.; Ahsan, M.; Alexeev, G.D.; Alkhazov, Georgiy D.; Alton, Andrew K.; /Michigan U. /Northeastern U.

    2008-08-01

    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.

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

    DOE Patents [OSTI]

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

    2014-01-21

    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.

  9. Search for pair-produced resonances decaying to jet pairs in proton–proton collisions at ?s = 8 TeV

    E-Print Network [OSTI]

    Apyan, Aram

    Results are reported of a general search for pair production of heavy resonances decaying to pairs of hadronic jets in events with at least four jets. The study is based on up to 19.4 fb[superscript ?1] of integrated ...

  10. Distinguishing LSP archetypes via gluino pair production at LHC13

    E-Print Network [OSTI]

    Baris Altunkaynak; Howard Baer; Vernon Barger; Peisi Huang

    2015-06-30

    The search for supersymmetry at Run 1 of LHC has resulted in gluino mass limits m(gluino)>~ 1.3 TeV for the case where m(gluino)RNS) and a higgsino-like LSP. In all three cases we expect heavy-to-very-heavy squarks as suggested by a decoupling solution to the SUSY flavor and CP problems and by the gravitino problem. For all cases, initial SUSY discovery would likely occur in the multi-b-jet + ETMISS channel. The CSB scenario would be revealed by the presence of highly-ionizing, terminating tracks from quasi-stable charginos. As further data accrue, the RNS scenario with 100-200 GeV higgsino-like LSPs would be revealed by the build-up of a mass edge/bump in the OS/SF dilepton invariant mass which is bounded by the neutralino mass difference. The mSUGRA/CMSSM archetype would contain neither of these features but would be revealed by a buildup of the usual multi-lepton cascade decay signatures.

  11. X-ray Emission from Ionized Wind-Bubbles around Wolf-Rayet Stars

    E-Print Network [OSTI]

    Dwarkadas, Vikram V

    2015-01-01

    Using a code that employs a self-consistent method for computing the effects of photoionization on circumstellar gas dynamics, we model the formation of wind-driven nebulae around massive Wolf-Rayet (W-R) stars. Our algorithm incorporates a simplified model of the photo-ionization source, computes the fractional ionization of hydrogen due to the photoionizing flux and recombination, and determines self-consistently the energy balance due to ionization, photo-heating and radiative cooling. We take into account changes in stellar properties and mass-loss over the star's evolution. Our multi-dimensional simulations clearly reveal the presence of strong ionization front instabilities. Using various X-ray emission models, and abundances consistent with those derived for W-R nebulae, we compute the X-ray flux and spectra from our wind bubble models. We show the evolution of the X-ray spectral features with time over the evolution of the star, taking the absorption of the X-rays by the ionized bubble into account. O...

  12. Propagation of ionizing radiation in HII regions: the effects of optically thick density fluctuations

    E-Print Network [OSTI]

    C. Giammanco; J. E. Beckman; A. Zurita; M. Relaño

    2004-05-24

    The accepted explanation of the observed dichotomy of two orders of magnitude between in situ measurements of electron density in HII regions, derived from emission line ratios, and average measurements based on integrated emission measure, is the inhomogeneity of the ionized medium. This is expressed as a "filling factor", the volume ratio of dense to tenuous gas, measured with values of order 10^-3. Implicit in the filling factor model as normally used, is the assumption that the clumps of dense gas are optically thin to ionizing radiation. Here we explore implications of assuming the contrary: that the clumps are optically thick. A first consequence is the presence within HII regions of a major fraction of neutral hydrogen. We estimate the mean H^o/H^+ ratio for a population of HII regions in the spiral galaxy NGC 1530 to be the order of 10, and support this inference using dynamical arguments. The optically thick clumpy models allow a significant fraction of the photons generated by the ionizing stars to escape from their HII region. We show, by comparing model predictions with observations, that these models give an account at least as good as, and probably better than that of conventional models, of the radial surface brightness distribution and of selected spectral line diagnostics for physical conditions within HII regions. These models explain how an HII region can appear, from its line ratios, to be ionization bounded, yet permit a major fraction of its ionizing photons to escape.

  13. Reduction in maximum time uncertainty of paired time signals

    DOE Patents [OSTI]

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

    1981-02-11

    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.

  14. Reconstructing particle masses from pairs of decay chains

    E-Print Network [OSTI]

    Mihoko M. Nojiri; Kazuki Sakurai; Bryan R. Webber

    2010-06-01

    A method is proposed for determining the masses of the new particles N,X,Y,Z in collider events containing a pair of effectively identical decay chains Z to Y+jet, Y to X+l_1, X to N+l_2, where l_1, l_2 are opposite-sign same-flavour charged leptons and N is invisible. By first determining the upper edge of the dilepton invariant mass spectrum, we reduce the problem to a curve for each event in the 3-dimensional space of mass-squared differences. The region through which most curves pass then determines the unknown masses. A statistical approach is applied to take account of mismeasurement of jet and missing momenta. The method is easily visualized and rather robust against combinatorial ambiguities and finite detector resolution. It can be successful even for small event samples, since it makes full use of the kinematical information from every event.

  15. Kaon pair production in proton-nucleus collisions

    E-Print Network [OSTI]

    Yu. T. Kiselev; M. Hartmann; A. Polyanskiy; E. Ya. Paryev; S. Barsov; M. Buescher; S. Dymov; R. Gebel; V. Hejny; A. Kacharava; I. Keshelashvili; B. Lorentz; Y. Maeda; S. Merzliakov; S. Mikirtytchiants; H. Ohm; V. Serdyuk; A. Sibirtsev; V. Y. Sinitsyna; H. J. Stein; H. Stroeher; S. Trusov; Yu. Valdau; C. Wilkin; P. Wuestner; Q. J. Ye

    2015-09-16

    The production of non-phi K+K- pairs by protons of 2.83 GeV kinetic energy on C, Cu, Ag, and Au targets has been investigated using the COSY-ANKE magnetic spectrometer. The K- momentum dependence of the differential cross section has been measured at small angles over the 0.2--0.9 GeV/c range. The comparison of the data with detailed model calculations indicates an attractive K- -nucleus potential of about -60 MeV at normal nuclear matter density at a mean momentum of 0.5 GeV/c. However, this approach has difficulty in reproducing the smallness of the observed cross sections at low K- momenta.

  16. Kaon pair production in proton-nucleus collisions

    E-Print Network [OSTI]

    Kiselev, Yu T; Polyanskiy, A; Paryev, E Ya; Barsov, S; Buescher, M; Dymov, S; Gebel, R; Hejny, V; Kacharava, A; Keshelashvili, I; Lorentz, B; Maeda, Y; Merzliakov, S; Mikirtytchiants, S; Ohm, H; Serdyuk, V; Sibirtsev, A; Sinitsyna, V Y; Stein, H J; Stroeher, H; Trusov, S; Valdau, Yu; Wilkin, C; Wuestner, P; Ye, Q J

    2015-01-01

    The production of non-phi K+K- pairs by protons of 2.83 GeV kinetic energy on C, Cu, Ag, and Au targets has been investigated using the COSY-ANKE magnetic spectrometer. The K- momentum dependence of the differential cross section has been measured at small angles over the 0.2--0.9 GeV/c range. The comparison of the data with detailed model calculations indicates an attractive K- -nucleus potential of about -60 MeV at normal nuclear matter density at a mean momentum of 0.5 GeV/c. However, this approach has difficulty in reproducing the smallness of the observed cross sections at low K- momenta.

  17. Valley pair qubits in double quantum dots of gapped graphene

    E-Print Network [OSTI]

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

    2011-07-03

    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)).

  18. One-photon pair production on de Sitter spacetime

    E-Print Network [OSTI]

    Blaga, Robert

    2015-01-01

    We study the one-photon scalar pair production QED process on the expanding de Sitter spacetime. Using perturbation theory, we obtain the transition probability and study its properties as a function of the expansion parameter $\\omega$. On flat space the process is forbidden by energy-momentum conservation. It is expected that for a dynamical background there is an energy exchange correlate to the strength of the gravitational field. We use momentum space plots and compute the mean production angle to illustrate this. We show that the mean angle grows with $\\omega$, but also find that in the flat limit the fall-off is unexpectedly slow. To investigate this further we obtain the probability around different angular configuration, at leading order in $m/\\omega$, and find that the $\\omega$ dependence at small angles is very weak. We comment on the possible astrophysical implications.

  19. Pair creation in an electric flux tube and chiral anomaly

    SciTech Connect (OSTI)

    Iwazaki, Aiichi [International Economics and Politics, Nishogakusha University, Ohi Kashiwa, Chiba 277-8585 (Japan)

    2009-11-15

    Using the chiral anomaly, we discuss the pair creation of massless fermions under the effect of a magnetic field B-vector when an electric flux tube E-vector parallel to B-vector is switched on. The tube is axially symmetric and infinitely long. For the constraint B>>E, we can analytically obtain the spatial and temporal behaviors of the number density of the fermions, the azimuthal magnetic field generated by the fermions, and so on. We find that the lifetime t{sub c} of the electric field becomes shorter as the width of the tube becomes narrower. Applying it to the plasma in high-energy heavy-ion collisions, we find that the color electric field decays quickly such that t{sub c}{approx_equal}Q{sub s}{sup -1}, in which Q{sub s} is the saturation momentum.

  20. Alignment-dependent fluorescence emission induced by tunnel ionization of carbon dioxide from lower-lying orbitals

    E-Print Network [OSTI]

    Yao, Jinping; Jia, Xinyan; Hao, Xiaolei; Zeng, Bin; Jing, Chenrui; Chu, Wei; Ni, Jielei; Zhang, Haisu; Xie, Hongqiang; Zhang, Chaojin; Zhao, Zengxiu; Chen, Jing; Liu, Xiaojun; Cheng, Ya; Xu, Zhizhan

    2013-01-01

    We show that fluorescence emission induced by strong field tunnel ionization of carbon dioxide from its lower-lying orbitals exhibits a peculiar molecular alignment dependence. The experimentally measured alignment-dependence of the fluorescence agrees with the alignment-dependence of the ionization probability calculated in the framework of the strong field approximation. Our results demonstrate the feasibility of an all-optical approach for shedding more light on the ionization mechanisms of molecules from their lower-lying orbitals in tunnel ionization regime.

  1. A VUV Photoionization and Ab Initio Determination of the Ionization Energy of a Gas Phase Sugar (Deoxyribose).

    E-Print Network [OSTI]

    Ghosh, Debashree

    2012-01-01

    electronic structure calculations of vertical and adiabatic ionization energies. Ab initio molecular dynamics (dynamics snapshots along the reaction coordinate. Keywords: sugars, synchrotron radiation, electronic structure calculations,

  2. Ionization of oriented carbonyl sulfide molecules by intense circularly polarized laser pulses

    SciTech Connect (OSTI)

    Dimitrovski, Darko; Abu-samha, Mahmoud; Madsen, Lars Bojer; Filsinger, Frank; Meijer, Gerard; Kuepper, Jochen [Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin (Germany); Holmegaard, Lotte; Kalhoej, Line [Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Nielsen, Jens H. [Department of Physics, Aarhus University, DK-8000 Aarhus C (Denmark); Stapelfeldt, Henrik [Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C (Denmark)

    2011-02-15

    We present combined experimental and theoretical results on strong-field ionization of oriented carbonyl sulfide molecules by circularly polarized laser pulses. The obtained molecular frame photoelectron angular distributions show pronounced asymmetries perpendicular to the direction of the molecular electric dipole moment. These findings are explained by a tunneling model invoking the laser-induced Stark shifts associated with the dipoles and polarizabilities of the molecule and its unrelaxed cation. The focus of the present article is to understand the strong-field ionization of one-dimensionally-oriented polar molecules, in particular asymmetries in the emission direction of the photoelectrons. In the following article [Phys. Rev. A 83, 023406 (2011)] the focus is to understand strong-field ionization from three-dimensionally-oriented asymmetric top molecules, in particular the suppression of electron emission in nodal planes of molecular orbitals.

  3. Reconstruction of ionization probabilities from spatially averaged data in N dimensions

    SciTech Connect (OSTI)

    Strohaber, J.; Kolomenskii, A. A.; Schuessler, H. A.

    2010-07-15

    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 two dimensions, and probabilities in the postsaturation region, where the intensity-selective scanning approach breaks down, were recovered. In three dimensions, ionization probabilities of Xe were successfully recovered with MPE from simulated (using the Ammosov-Delone-Krainov tunneling theory) ion yields. Finally, we tested our approach with intensity-resolved benzene-ion yields, which show a resonant multiphoton ionization process. By applying MPE to this data (which were artificially averaged), the resonant structure was recovered, which suggests that the resonance in benzene may have been observed in spatially averaged data taken elsewhere.

  4. An Open Port Sampling Interface for Liquid Introduction Atmospheric Pressure Ionization Mass Spectrometry

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

    Van Berkel, Gary J.; Kertesz, Vilmos

    2015-08-25

    RATIONALE: A simple method to introduce unprocessed samples into a solvent for rapid characterization by liquid introduction atmospheric pressure ionization mass spectrometry has been lacking. The continuous flow, self-cleaning open port sampling interface introduced here fills this void. METHODS: The open port sampling interface used a vertically aligned, co-axial tube arrangement enabling solvent delivery to the sampling end of the device through the tubing annulus and solvent aspiration down the center tube and into the mass spectrometer ionization source via the commercial APCI emitter probe. The solvent delivery rate to the interface was set to exceed the aspiration rate creatingmore »a continuous sampling interface along with a constant, self-cleaning spillover of solvent from the top of the probe. RESULTS: Using the open port sampling interface with positive ion mode APCI and a hybrid quadrupole time of flight mass spectrometer, rapid, direct sampling and analysis possibilities are exemplified with plastics, ballpoint and felt tip ink pens, skin, and vegetable oils. These results demonstrated that the open port sampling interface could be used as a simple, versatile and self-cleaning system to rapidly introduce multiple types of unprocessed, sometimes highly concentrated and complex, samples into a solvent flow stream for subsequent ionization and analysis by mass spectrometry. The basic setup presented here could be incorporated with any self-aspirating liquid introduction ionization source (e.g., ESI, APCI, APPI, ICP, etc.) or any type of atmospheric pressure sampling ready mass spectrometer system. CONCLUSIONS: The open port sampling interface provides a means to introduce and quickly analyze unprocessed solid or liquid samples with liquid introduction atmospheric pressure ionization source without fear of sampling interface or ionization source contamination.« less

  5. NGC 1365: A low column density state unveiling a low ionization disk wind

    SciTech Connect (OSTI)

    Braito, V.; Reeves, J. N.; Gofford, J.; Nardini, E.; Porquet, D.; Risaliti, G.

    2014-11-01

    We present the time-resolved spectral analysis of the XMM-Newton data of NGC 1365 collected during one XMM-Newton observation, which caught this 'changing-look' active galactic nucleus in a high flux state characterized also by a low column density (N {sub H} ? 10{sup 22} cm{sup –2}) of the X-ray absorber. During this observation, the low-energy photoelectric cut-off is at about ?1 keV and the primary continuum can be investigated with the XMM-Newton-RGS data, which show strong spectral variability that can be explained as a variable low N {sub H} that decreased from N {sub H} ? 10{sup 23} cm{sup –2} to 10{sup 22} cm{sup –2} in a 100 ks timescale. The spectral analysis of the last segment of the observation revealed the presence of several absorption features that can be associated with an ionized (log ? ? 2 erg cm s{sup –1}) outflowing wind (v {sub out} ? 2000 km s{sup –1}). We detected for the first time a possible P-Cygni profile of the Mg XII Ly? line associated with this mildly ionized absorber indicative of a wide angle outflowing wind. We suggest that this wind is a low ionization zone of the highly ionized wind present in NGC 1365, which is responsible for the iron K absorption lines and is located within the variable X-ray absorber. At the end of the observation, we detected a strong absorption line at E ? 0.76 keV most likely associated with a lower ionization zone of the absorber (log ? ? 0.2 erg cm s{sup –1}, N {sub H} ? 10{sup 22} cm{sup –2}), which suggests that the variable absorber in NGC 1365 could be a low ionization zone of the disk wind.

  6. Resonance ionization laser ion sources for on-line isotope separators (invited)

    SciTech Connect (OSTI)

    Marsh, B. A. [EN Department, CERN, 1211 Geneva (Switzerland)] [EN Department, CERN, 1211 Geneva (Switzerland)

    2014-02-15

    A Resonance Ionization Laser Ion Source (RILIS) is today considered an essential component of the majority of Isotope Separator On Line (ISOL) facilities; there are seven laser ion sources currently operational at ISOL facilities worldwide and several more are under development. The ionization mechanism is a highly element selective multi-step resonance photo-absorption process that requires a specifically tailored laser configuration for each chemical element. For some isotopes, isomer selective ionization may even be achieved by exploiting the differences in hyperfine structures of an atomic transition for different nuclear spin states. For many radioactive ion beam experiments, laser resonance ionization is the only means of achieving an acceptable level of beam purity without compromising isotope yield. Furthermore, by performing element selection at the location of the ion source, the propagation of unwanted radioactivity downstream of the target assembly is reduced. Whilst advances in laser technology have improved the performance and reliability of laser ion sources and broadened the range of suitable commercially available laser systems, many recent developments have focused rather on the laser/atom interaction region in the quest for increased selectivity and/or improved spectral resolution. Much of the progress in this area has been achieved by decoupling the laser ionization from competing ionization processes through the use of a laser/atom interaction region that is physically separated from the target chamber. A new application of gas catcher laser ion source technology promises to expand the capabilities of projectile fragmentation facilities through the conversion of otherwise discarded reaction fragments into high-purity low-energy ion beams. A summary of recent RILIS developments and the current status of laser ion sources worldwide is presented.

  7. Pairing Interaction in N=Z Nuclei with Half-filled High-j Shell

    E-Print Network [OSTI]

    A. Juodagalvis

    2000-04-21

    The role of L=0 pairing interactions (both T=0 and T=1) in three selected bands with the total isospin T=0 in 22Na, 48Cr and 90Rh nuclei is discussed in the spherical shell model. These bands were selected requiring termination in a most unfavourable way. The investigated effects coming from pairing interactions include the change of nuclear wavefunction, quadrupole properties and state energy. To follow the gradual change of nuclear properties, the investigation is performed in a perturbative approach by defining the Hamiltonian with a variable content of the pairing interaction. It is shown that the pairing does not affect the quadrupole properties, if the energy distance to other close lying states is large. The calculated pairing energy is shown to have a similar spin dependence in these three bands. In addition, the influence of the model space as well as of the residual interaction on the derived pairing energy is discussed.

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

    E-Print Network [OSTI]

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

    2014-10-16

    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.

  9. Multi-electron dynamics in the tunnel ionization of correlated quantum systems

    E-Print Network [OSTI]

    Hollstein, Maximilian

    2015-01-01

    The importance of multi-electron dynamics during the tunnel ionization of a correlated quantum system is investigated. By comparison of the solution of the time-dependent Schr\\"odinger equation (TDSE) with the time-dependent configuration interaction singles approach (TDCIS), we demonstrate the importance of a multi-electron description of the tunnel ionization process especially for weakly confined quantum systems. Within this context, we observe that adiabatic driving by an intense light field can even enhance the correlations between still trapped electrons.

  10. Hydrogen atoms in circularly polarized microwave fields: Near-integrability and ionization

    E-Print Network [OSTI]

    Rakovi?, M. J.; Chu, Shih-I

    1995-08-01

    as one of the paradigms for the study of "quantum chaos. " A related problem, of more recent in- terest, is the ionization of Rydberg atoms in the presence of circularly polarized (CP) microwave fields. A recent experiment [3] on microwave ionization... systems I and II. Con- sider the energy momentum map-[8] corresponding to the integrable system II: AfsM: P~)R': (r, p)~(H(r, p), I(r, p), J(r, p)), A,FM(P)=Q . where Q C:IR is the image of the phase space P under the energy-momentum map. Let M(r, p...

  11. Efficient electronic structure calculation for molecular ionization dynamics at high x-ray intensity

    E-Print Network [OSTI]

    Hao, Yajiang; Hanasaki, Kota; Son, Sang-Kil; Santra, Robin

    2015-01-01

    We present the implementation of an electronic-structure approach dedicated to ionization dynamics of molecules interacting with x-ray free-electron laser (XFEL) pulses. In our scheme, molecular orbitals for molecular core-hole states are represented by linear combination of numerical atomic orbitals that are solutions of corresponding atomic core-hole states. We demonstrate that our scheme efficiently calculates all possible multiple-hole configurations of molecules formed during XFEL pulses. The present method is suitable to investigate x-ray multiphoton multiple ionization dynamics and accompanying nuclear dynamics, providing essential information on the chemical dynamics relevant for high-intensity x-ray imaging.

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

    SciTech Connect (OSTI)

    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)

    2013-06-15

    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.

  13. Ionization-assisted relativistic electron generation with monoenergetic features from laser thin foil interaction

    SciTech Connect (OSTI)

    Glazyrin, I. V.; Karpeev, A. V.; Kotova, O. G.; Bychenkov, V. Yu.; Fedosejevs, R.; Rozmus, W. [Russian Federal Nuclear Center - E.I.Zababakhin Institute of Technical Physics, Snezhinsk, Chelyabinsk Region 456770 (Russian Federation); P. N. Lebedev Physics Institute RAS, Leninskii Prospect 53, Moscow 119991 (Russian Federation); Department of Electrical and Computer Engineering, University of Alberta, Edmonton T6G 2V4, Alberta (Canada); Theoretical Physics Institute, University of Alberta, Edmonton T6G 2G7, Alberta (Canada)

    2012-07-11

    The concept of ionization-induced injection into the laser pulse to produce quasi-monoenergetic bunches of electrons from ultra-thin solid dense targets is analyzed. When the laser pulse propagates through semi-transparent foil the electrons from inner atom shells remain bound during the rise time of the laser pulse and are ionized by the laser intensity near its maximum amplitude, which satisfies the best injection condition for subsequent acceleration. It was found that a bunch of quasimonoenergetic electrons from inner atom shells moves co-directionally with laser pulse and acquire energy {approx}m{sub e}c{sup 2}a{sup 2}/2.

  14. Drifting potential humps in ionization zones: The “propeller blades” of high power impulse magnetron sputtering

    SciTech Connect (OSTI)

    Anders, André; Ni, Pavel; Panjan, Matjaž; Jožef Stefan Institute, Jamova 39, 1000 Ljubljana ; Franz, Robert; Montanuniversität Leoben, Franz-Josef-Strasse 18, 8700 Leoben ; Andersson, Joakim; Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore

    2013-09-30

    Ion energy distribution functions measured for high power impulse magnetron sputtering show features, such as a broad peak at several 10 eV with an extended tail, as well as asymmetry with respect to E×B, where E and B are the local electric and magnetic field vectors, respectively. Here it is proposed that those features are due to the formation of a potential hump of several 10 V in each of the traveling ionization zones. Potential hump formation is associated with a negative-positive-negative space charge that naturally forms in ionization zones driven by energetic drifting electrons.

  15. Ionization of Water Clusters is Mediated by Exciton Energy Transfer from Argon Clusters

    SciTech Connect (OSTI)

    Golan, Amir; Ahmed, Musahid

    2012-01-25

    The exciton energy deposited in an argon cluster, (Arn ,< n=20>) using VUV radiation is transferred to softly ionize doped water clusters, ((H2O)n, n=1-9) leading to the formation of non-fragmented clusters. Following the initial excitation, electronic energy is channeled to ionize the doped water cluster while evaporating the Ar shell, allowing identification of fragmented and complete water cluster ions. Examination of the photoionization efficiency curve shows that cluster evaporation from excitons located above 12.6 eV are not enough to cool the energized water cluster ion, and leads to their dissociation to (H2O)n-2H+ (protonated) clusters.

  16. SPEAR far UV spectral imaging of highly ionized emission from the North Galactic Pole Region

    E-Print Network [OSTI]

    B. Y. Welsh; J. Edelstein; E. Korpela

    2007-06-06

    We present far ultraviolet (FUV: 912 - 1750AA) spectral imaging observations recorded with the SPEAR satellite of the interstellar OVI (1032AA), CIV (1550AA), SiIV (1394AA), SiII* (1533AA) and AlII (1671AA) emission lines originating in a 60 x 30 degree rectangular region lying close to the North Galactic Pole. These data represent the first large area, moderate spatial resolution maps of the distribution of UV spectral-line emission originating the both the highly ionized medium (HIM) and the warm ionized medium (WIM) recorded at high galactic latitudes.

  17. Pairing effect in thermal shape fluctuation model on the width of giant dipole resonance

    E-Print Network [OSTI]

    A. K. Rhine Kumar; P. Arumugam; N. Dinh Dang

    2014-09-23

    We present an approach that includes temperature-dependent shell effects and fluctuations of the pairing field in the thermal shape fluctuation model (TSFM). We apply this approach to study the width of giant dipole resonance (GDR) in $^{97}$Tc, $^{120}$Sn and $^{208}$Pb. Our results demonstrate that the TSFM that includes pairing fluctuations can explain the recently observed quenching in the GDR width. We also show that to validate pairing prescriptions and the parameters involved, we require more and precise data.

  18. Photons with tunable spectral shapes: The transition from frequency anticorrelated to correlated photon pairs

    E-Print Network [OSTI]

    M. Hendrych; M. Mi?uda; A. Valencia; J. P. Torres

    2009-08-13

    We present an experimental demonstration of the full control of the frequency correlations of entangled photon pairs. The joint spectrum of photon pairs is continuously varied from photons that exhibit anticorrelation in frequency to photons that exhibit correlation in frequency, passing through the case of uncorrelated photons. Highly entangled frequency-anticorrelated photon pairs were obtained even when an ultrafast laser was used as a pump. The different kinds of correlations are obtained without changing neither the wavelength, nor the nonlinear crystal.

  19. Pairing state with a time-reversal symmetry breaking in FeAs...

    Office of Scientific and Technical Information (OSTI)

    English Subject: 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; COMPETITION; ELECTRONS; GINZBURG-LANDAU THEORY; HOLES; ORDER PARAMETERS; PAIRING INTERACTIONS; RESONANCE;...

  20. Natural orbits of atomic Cooper pairs in a nonuniform Fermi gas

    E-Print Network [OSTI]

    Y. H. Pong; C. K. Law

    2006-05-08

    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.

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

    E-Print Network [OSTI]

    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

    2007-03-23

    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.

  2. Quantum efficiency measurement of single photon detectors using photon pairs generated in optical fibers

    E-Print Network [OSTI]

    Xiaoying Li; Xiaoxin Ma; Limei Quan; Lei Yang; Liang Cui; Xueshi Guo

    2010-07-14

    Using the correlated signal and idler photon pairs generated in a dispersion shifted fiber by a pulsed pump, we measure the quantum efficiency of a InGaAs/InP avalanche photodiode-based single photon detector. Since the collection efficiency of photon pairs is a key parameter to correctly deduce the quantum efficiency, we carefully characterize the collection efficiency by studying correlation dependence of photon pairs upon the spectra of pump, signal and idler photons. This study allows us to obtain quantum efficiency of the single photon detector by using photon pairs with various kinds of bandwidths.

  3. Exact solution of the p+ip Hamiltonian revisited: duality relations in the hole-pair picture

    E-Print Network [OSTI]

    Jon Links; Ian Marquette; Amir Moghaddam

    2015-04-02

    We study the exact Bethe Ansatz solution of the p+ip Hamiltonian in a form whereby quantum numbers of states refer to hole-pairs, rather than particle-pairs used in previous studies. We find an asymmetry between these approaches. For the attractive system states in the strong pairing regime take the form of a quasi-condensate involving two distinct hole-pair creation operators. An analogous feature is not observed in the particle-pair picture.

  4. Electron impact ionization: A new parameterization for 100 eV to 1 MeV electrons

    E-Print Network [OSTI]

    Jackman, Charles H.

    Electron impact ionization: A new parameterization for 100 eV to 1 MeV electrons Xiaohua Fang,1 of the ionization rate in the Earth's atmosphere due to precipitating energetic electrons. Precipitating electrons the atmosphere. In this study, two electron transport models (whose validity has been verified by observations

  5. International Journal of Mass Spectrometry 267 (2007) 8997 One-photon mass-analyzed threshold ionization spectroscopy (MATI)

    E-Print Network [OSTI]

    Kim, Myung Soo

    2007-01-01

    ionization (MATI) spectrum of cis-C2H2Cl2 was obtained by using vacuum ultravio- let radiation generated in the spectrum was 9.6578 ± 0.0006 eV. Ten vibrational fundamentals for the cation were identified. Most are ionized by electric field pulse. ZEKE and MATI spectra are obtained by recording the electron and ion

  6. Time Delays in Two-Photon Ionization Jing Su, Hongcheng Ni, Agnieszka Jaro-Becker, and Andreas Becker

    E-Print Network [OSTI]

    Becker, Andreas

    Time Delays in Two-Photon Ionization Jing Su, Hongcheng Ni, Agnieszka Jaro-Becker, and Andreas results of ab initio numerical simulations of time delays in two-photon ionization of the helium atom contributions, namely, a time delay acquired during the absorption of the two photons from the extreme

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

    E-Print Network [OSTI]

    Rocke, David M.

    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

  8. Ionization and fragmentation of C60 by highly charged, high-energy xenon ions S. Cheng,* H. G. Berry,

    E-Print Network [OSTI]

    Bauer, Wolfgang

    Ionization and fragmentation of C60 by highly charged, high-energy xenon ions S. Cheng,* H. G 19 June 1996 C60 vapor was bombarded by 136 Xe35 and 136 Xe18 ions in the energy range 420­625 MeV to study the various ionization and fragmentation processes that occur. Since the center-of-mass energies

  9. PHOTOIONIZATION OF JET COOLED MOLECULES AND Photo-ionization provides a forum of hyphenation for mass spectrometry since one can

    E-Print Network [OSTI]

    de Vries, Mattanjah S.

    PHOTOIONIZATION OF JET COOLED MOLECULES AND CLUSTERS Photo-ionization provides a forum-ionization the vibrational and rotational temperatures should be reduced by entertainment in a supersonic jet. For non nozzle. 1. Jet cooling Expanding a high-pressure gas through a small hole into a low pressure decreases

  10. Enhanced Stability of Electrohydrodynamic Jets through Gas Ionization Sibel Korkut, Dudley A. Saville,* and Ilhan A. Aksay

    E-Print Network [OSTI]

    Aksay, Ilhan A.

    Enhanced Stability of Electrohydrodynamic Jets through Gas Ionization Sibel Korkut, Dudley A of an electrohydrodynamic jet based on the measured total current overestimate experimental values. We show charge density of the jet. As a result of gas ionization, a sudden drop in the instability growth rate

  11. Space qualified nanosatellite electronics platform for photon pair experiments

    E-Print Network [OSTI]

    Cliff Cheng; Rakhitha Chandrasekara; Yue Chuan Tan; Alexander Ling

    2015-05-25

    We report the design and implementation of a complete electronics platform for conducting a quantum optics experiment that will be operated on board a 1U CubeSat (a 10 x 10 x 10 cm satellite). The quantum optics experiment is designed to produce polarization-entangled photon pairs using non-linear optical crystals and requires opto-electronic components such as a pump laser, single photon detectors and liquid crystal based polarization rotators in addition to passive optical elements. The platform provides mechanical support for the optical assembly. It also communicates autonomously with the host satellite to provide experiment data for transmission to a ground station. A limited number of commands can be transmitted from ground to the platform enabling it to switch experimental modes. This platform requires less than 1.5W for all operations, and is space qualified. The implementation of this electronics platform is a major step on the road to operating quantum communication experiments using nanosatellites.

  12. The Drinfel'd polynomial of a tridiagonal pair

    E-Print Network [OSTI]

    Ito, Tatsuro

    2008-01-01

    Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering $\\{V_i\\}{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering $\\{V^*_i\\}{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv) there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \

  13. Top Quark Properties from Top Pair Events and Decays

    E-Print Network [OSTI]

    Andrew G. Ivanov; for the CDF; Dzero Collaborations

    2008-10-19

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

  14. Two-dimensional simulations of pulsational pair-instability supernovae

    SciTech Connect (OSTI)

    Chen, Ke-Jung; Woosley, Stan [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Heger, Alexander [Monash Centre for Astrophysics, Monash University, Melbourne, Victoria 3800 (Australia); Almgren, Ann [Center for Computational Sciences and Engineering, Lawrence Berkeley National Lab, Berkeley, CA 94720 (United States); Whalen, Daniel J., E-mail: kchen@ucolick.org [T-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2014-09-01

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

  15. Neutrino-pair bremsstrahlung by electrons in neutron star crusts

    E-Print Network [OSTI]

    A. D. Kaminker; C. J. Pethick; A. Y. Potekhin; V. Thorsson; D. G. Yakovlev

    1998-12-25

    Neutrino-pair bremsstrahlung by relativistic degenerate electrons in a neutron-star crust at densities (10^9 - 1.5x10^{14}) g/cm^3 is analyzed. The processes taken into account are neutrino emission due to Coulomb scattering of electrons by atomic nuclei in a Coulomb liquid, and electron-phonon scattering and Bragg diffraction (the static-lattice contribution) in a Coulomb crystal. The static-lattice contribution is calculated including the electron band-structure effects for cubic Coulomb crystals of different types and also for the liquid crystal phases composed of rod- and plate-like nuclei in the neutron-star mantle (at 10^{14} - 1.5x10^{14} g/cm^3). The phonon contribution is evaluated with proper treatment of the multi-phonon processes which removes a jump in the neutrino bremsstrahlung emissivity at the melting point obtained in previous works. Below 10^{13} g/cm^3, the results are rather insensitive to the nuclear form factor, but results for the solid state near the melting point are affected significantly by the Debye-Waller factor and multi-phonon processes. At higher densities, the nuclear form factor becomes more significant. A comparison of the various neutrino generation mechanisms in neutron star crusts shows that electron bremsstrahlung is among the most important ones.

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

    SciTech Connect (OSTI)

    S?abkowska, K.; Szyma?ska, E.; Polasik, M.; Pereira, N. R.; Rzadkiewicz, J.; Seely, J. F.; Weber, B. V.; Schumer, J. W.

    2014-03-15

    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.

  17. Cancer risks attributable to low doses of ionizing radiation: Assessing what we really know

    E-Print Network [OSTI]

    Brenner, David Jonathan

    Cancer risks attributable to low doses of ionizing radiation: Assessing what we really know David J low radiation doses the situation is much less clear, but the risks of low-dose radiation terrorism. We review the difficulties involved in quantifying the risks of low-dose radiation and address

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

    SciTech Connect (OSTI)

    Azzam, Edouard I

    2013-01-16

    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.

  19. Laser-induced resonance states as dynamic suppressors of ionization in high-frequency short pulses

    E-Print Network [OSTI]

    Barash, Danny

    distorted to a metastable well form; the electron either tunnels through or crosses over a potential barrier of a laser-induced resonance state, which is coupled by the pulse ramp to the ground state and acts to trap ionizing flux. PACS number s : 32.80.Rm I. INTRODUCTION The interaction of atomic electrons with intense

  20. Stability of negative ionization fronts: Regularization by electric screening? Manuel Arrayas1,2

    E-Print Network [OSTI]

    Ebert, Ute

    investigate how transversal Fourier modes of a planar ionization front are regularized by the electric the formation of cusps. The nature of this regularization has to be derived from the underlying gas discharge physics; it recently has been a subject of debate 13,14 . We argue that one regular- ization mechanism

  1. Intensity-resolved ionization yields of aniline with femtosecond laser pulses

    SciTech Connect (OSTI)

    Strohaber, J.; Hart, N.; Zhu, F.; Nava, R.; Pham, F.; Kolomenskii, A. A.; Paulus, G. G.; Schuessler, H. A.; Mohamed, T.; Schroeder, H.

    2011-12-15

    We present experimental results for the ionization of aniline and benzene molecules subjected to intense ultrashort laser pulses. Measured parent molecular ions yields were obtained using a recently developed technique capable of three-dimensional imaging of ion distributions within the focus of a laser beam. By selecting ions originating from the central region of the focus, where the spatial intensity distribution is nearly uniform, volumetric-free intensity-dependent ionization yields were obtained. The measured data revealed a previously unseen resonance-enhanced multiphoton ionization (REMPI)-like process. Comparison of benzene, aniline, and Xe ion yields demonstrates that the observed intensity-dependent structures are not due to geometric artifacts in the focus. Finally for intensities greater than {approx}3x10{sup 13} W/cm{sup 2}, we attribute the ionization of aniline to a stepwise process going through the {pi}{sigma}{sup *} state which sits three photons above the ground state and two photons below the continuum.

  2. First detection of an ultraviolet transition in an ionized polycyclic aromatic hydrocarbon

    E-Print Network [OSTI]

    ; accepted 3 May 1999 We report the first measurement of a polycyclic aromatic hydrocarbon cation electronicFirst detection of an ultraviolet transition in an ionized polycyclic aromatic hydrocarbon Xavier D of Physics. S0021-9606 99 02226-6 I. INTRODUCTION Polycyclic aromatic hydrocarbon PAH ions are prom- ising

  3. Photo-triggering and secondary electron produced ionization in electric discharge ArF* excimer lasers

    E-Print Network [OSTI]

    Kushner, Mark

    . It is well known that an adequate initial photo-electron density is critical to main- taining a stablePhoto-triggering and secondary electron produced ionization in electric discharge ArF* excimer photo- electron density in the inter-electrode spacing is around 108 cmÀ3 , and its distribution

  4. The Effects of Ionizing Irradiation on Liquid, Dried, and Absorbed DNA Extracts

    E-Print Network [OSTI]

    The Effects of Ionizing Irradiation on Liquid, Dried, and Absorbed DNA Extracts With and Without from FBI and national public health experts, began irradiating mail to kill potentially present anthrax Formation in Irradiated Tubes High dose X ray Low dose X ray pH indicator wet dry D-BM wet dry D-BM wet dry

  5. Radio frequency induced ionized collisional flow model for application at atmospheric pressures

    E-Print Network [OSTI]

    Roy, Subrata

    Radio frequency induced ionized collisional flow model for application at atmospheric pressures and radio frequency (rf) induced plasma-sheath dynamics, using multifluid equations. For the former, argon inherent in nonequilibrium discharges such as obtained through radio frequency (rf) or microwave excitation

  6. Ionization of carbon, nitrogen, and oxygen by electron impact Yong-Ki Kim

    E-Print Network [OSTI]

    in experiments may be in excited, low-lying metastable states. The binary- encounter Bethe BEB model of Kim to determine the contributions from excitation-autoionization. A sum of the BEB cross sections for direct ionization cross sections. The combination of the BEB model and the scaled Born cross sections

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

    E-Print Network [OSTI]

    Kim, Sang Kyu

    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

  8. Collisions of low-energy antiprotons with molecular hydrogen: ionization, excitation and stopping power

    E-Print Network [OSTI]

    Lühr, Armin

    2008-01-01

    A time-dependent coupled-channel approach was used to calculate ionization, excitation, and energy-loss cross sections as well as energy spectra for antiproton and proton collisions with molecular hydrogen for impact energies 8 keV < E < 4000 keV.

  9. Stabilization against ionization via high-Rydberg states A. Wojcik, R. Parzynski, and A. Grudka

    E-Print Network [OSTI]

    Wójcik, Antoni

    is presented of two models of intense-laser ionization from an isolated initial state via a band of high. Within these models we draw conclusions about the efficiency of migration, the initial-state lifetime of the circular 5g neon state with a single-photon energy being nearly four times the elec- tron binding energy

  10. Astrochemical Constraints on the Cosmic-Ray Ionization Rate Nick Indriolo

    E-Print Network [OSTI]

    McCall, Benjamin J.

    as the primary ionization source in regions where the density severely limits the entry of high energy photons to within about an order of magnitude. There are a few main reasons for this uncertainty. The low energy to the magnetic field coupled to the solar wind. Because they are easily deflected, we have no direct measure

  11. Isomer discrimination of polycyclic aromatic hydrocarbons in the Murchison meteorite by resonant ionization

    E-Print Network [OSTI]

    de Vries, Mattanjah S.

    Isomer discrimination of polycyclic aromatic hydrocarbons in the Murchison meteorite by resonant between isomers of polycyclic aromatic hydrocarbons in the Murchison meteorite. We measured the 2C-R2PI: Resonant ionization; Jet cooling; Mass spectrometry; Polycyclic aromatic hydrocarbons; Murchison meteorite

  12. E-beam ionized channel guiding of an intense relativistic electron beam

    DOE Patents [OSTI]

    Frost, Charles A. (Albuquerque, NM); Godfrey, Brendon B. (Albuquerque, NM); Kiekel, Paul D. (Albuquerque, NM); Shope, Steven L. (Albuquerque, NM)

    1988-01-01

    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.

  13. RESONANTLY DAMPED KINK MAGNETOHYDRODYNAMIC WAVES IN A PARTIALLY IONIZED FILAMENT THREAD

    SciTech Connect (OSTI)

    Soler, R.; Oliver, R.; Ballester, J. L. E-mail: ramon.oliver@uib.e

    2009-12-10

    Transverse oscillations of solar filament and prominence threads have been frequently reported. These oscillations have the common features of being of short period (2-10 minutes) and being damped after a few periods. The observations are interpreted as kink magnetohydrodynamic (MHD) wave modes, whereas resonant absorption in the Alfven continuum and ion-neutral collisions are candidates to be the damping mechanisms. Here, we study both analytically and numerically the time damping of kink MHD waves in a cylindrical, partially ionized filament thread embedded in a coronal environment. The thread model is composed of a straight and thin, homogeneous filament plasma, with a transverse inhomogeneous transitional layer where the plasma physical properties vary continuously from filament to coronal conditions. The magnetic field is homogeneous and parallel to the thread axis. We find that the kink mode is efficiently damped by resonant absorption for typical wavelengths of filament oscillations, the damping times being compatible with the observations. Partial ionization does not affect the process of resonant absorption, and the filament plasma ionization degree is only important for the damping for wavelengths much shorter than those observed. To our knowledge, this is the first time that the phenomenon of resonant absorption is studied in a partially ionized plasma.

  14. E-beam ionized channel guiding of an intense relativistic electron beam

    DOE Patents [OSTI]

    Frost, C.A.; Godfrey, B.B.; Kiekel, P.D.; Shope, S.L.

    1988-05-10

    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.

  15. Calculation of the cosmic ray induced ionization for the region P Makrantoni1

    E-Print Network [OSTI]

    Usoskin, Ilya G.

    Calculation of the cosmic ray induced ionization for the region of Athens P Makrantoni1 , H(T,) is the differential energy spectrum of galactic cosmic rays in the Earth's vicinity (given in units of [cm2 sec sr (GeV/nuc)]-1 ). Integration is performed above Tc,i , which is the kinetic energy of a particle of i-th type

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

    E-Print Network [OSTI]

    Yang, Jian

    photoluminescent polymers using new ionic liquid matrices Carlos A. Serrano1 , Yi Zhang2 , Jian Yang2 and Kevin A elucidation of recently developed aliphatic biodegradable polymers by matrixassisted laser desorption/ionization mass spectrometry (MALDIMS). The polymers, formed by a condensation reaction of three components

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

    SciTech Connect (OSTI)

    Battista, John R

    2010-02-22

    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.

  18. ECE 103 Solid State Electronics Master Exam 2012 Assume silicon, room temperature, complete ionization.

    E-Print Network [OSTI]

    Wang, Deli

    ECE 103 Solid State Electronics Master Exam 2012 Assume silicon, room temperature, complete ionization. (q=1.6×10-19 C, ox=3.9×8.85×10-14 F/cm, si=11.7×8.85×10-14 F/cm, kT/q=0.0259 V, Eg=1.12 e

  19. Pairing properties and specific heat of the inner crust of a neutron star

    E-Print Network [OSTI]

    A. Pastore

    2014-12-29

    We investigate the pairing properties at finite temperature of the Wigner-Seitz cells in the inner crust of a neutron star obtained with the recent Brussels-Montreal Skyrme functional BSk21. In particular we analyze the phenomena of persistence and reentrance of pairing correlations and their impact on the specific heat in the low-density region of the inner crust.

  20. Pairing properties and specific heat of the inner crust of a neutron star

    E-Print Network [OSTI]

    Pastore, A

    2014-01-01

    We investigate the pairing properties at finite temperature of the Wigner-Seitz cells in the inner crust of a neutron star obtained with the recent Brussels-Montreal Skyrme functional BSk21. In particular we analyze the phenomena of persistence and reentrance of pairing correlations and their impact on the specific heat in the low-density region of the inner crust.

  1. FOURIER PAIRS OF DISCRETE SUPPORT WITH LITTLE STRUCTURE MIHAIL N. KOLOUNTZAKIS

    E-Print Network [OSTI]

    Kolountzakis, Mihalis

    FOURIER PAIRS OF DISCRETE SUPPORT WITH LITTLE STRUCTURE MIHAIL N. KOLOUNTZAKIS Abstract. We give line of discrete support, whose Fourier Transform is also a measure of discrete support, yet this Fourier pair cannot be constructed by repeatedly applying the Poisson Summation Formula finitely many

  2. Induction logging device with a pair of mutually perpendicular bucking coils

    DOE Patents [OSTI]

    Koelle, Alfred R. (Los Alamos, NM); Landt, Jeremy A. (Los Alamos, NM)

    1981-01-01

    An instrument is disclosed for mapping vertical conductive fractures in a resistive bedrock, magnetically inducing eddy currents by a pair of vertically oriented, mutually perpendicular, coplanar coils. The eddy currents drive magnetic fields which are picked up by a second, similar pair of coils.

  3. Pairing-Based Onion Routing with Improved Forward Secrecy Aniket Kate Greg M. Zaverucha Ian Goldberg

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    to scale gracefully. Keywords: onion routing, Tor, pairing-based cryptography, anonymous key agreementPairing-Based Onion Routing with Improved Forward Secrecy Aniket Kate Greg M. Zaverucha Ian {akate,gzaveruc,iang}@cs.uwaterloo.ca Abstract This paper presents new protocols for onion routing

  4. AN ASSESSMENT OF WOOD DUCK DISTRIBUTION, ABUNDANCE AND RIPARIAN BREEDING PAIR HABITATS IN SOUTH DAKOTA

    E-Print Network [OSTI]

    AN ASSESSMENT OF WOOD DUCK DISTRIBUTION, ABUNDANCE AND RIPARIAN BREEDING PAIR HABITATS IN SOUTH #12;AN ASSESSMENT OF WOOD DUCK DISTRIBUTION, ABUNDANCE AND RIPARIAN BREEDING PAIR HABITATS IN SOUTH Wildlife and Fisheries Sciences #12;AN ASSESSMENT OF WOOD DUCK DISTRIBUTION, ABUNDANCE AND RIPARIAN

  5. Monte Carlo studies of directional pair ordering in disordered binary and ternary ferromagnetic BCC crystalline alloys

    E-Print Network [OSTI]

    Laughlin, David E.

    crystalline alloys P. R. Ohodnicki,a M. E. McHenry, and D. E. Laughlin Materials Science and Engineering ordering in bcc crystalline alloys using the Néel pair model and a Metropolis-type algorithm are reported alloys including poly- crystalline Ni­Fe.6,7 Recently, directional pair ordering in a crystalline phase

  6. Kinetic Energy Driven Pairing in Cuprate Superconductors Th. A. Maier,1

    E-Print Network [OSTI]

    Jarrell, Mark

    to the potential energy that electrons can gain by forming Cooper pairs. However, recent optical experiments showKinetic Energy Driven Pairing in Cuprate Superconductors Th. A. Maier,1 M. Jarrell,2 A. Macridin,2 of the electronic potential energy accompanied by an increase in kinetic energy. In the underdoped cuprates, optical

  7. Differential top pair cross section and top anti-top plus jets Physics

    E-Print Network [OSTI]

    Malgorzata Worek

    2013-02-14

    A brief summary of the current status of the next-to-leading order QCD corrections to top quark pair production and the associated production of top anti-top with jet(s) in different configurations, i.e. with one jet, two jets and another top anti-top pair, is presented.

  8. Affine Pairings on ARM Tolga Acar, Kristin Lauter, Michael Naehrig, and Daniel Shumow

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    Affine Pairings on ARM Tolga Acar, Kristin Lauter, Michael Naehrig, and Daniel Shumow Microsoft and projective pairings on a dual-core Cortex A9 ARM processor and compare perfor- mance of the same implementation across three platforms: x86, x86-64 and ARM. Using a fast inversion in the base field and doing

  9. Nuclear Physics A 781 (2007) 317341 Symmetry energies, pairing energies, and mass

    E-Print Network [OSTI]

    O'Donnell, Tom

    2007-01-01

    Nuclear Physics A 781 (2007) 317­341 Symmetry energies, pairing energies, and mass equations J and pairing energies of atomic nuclei are related to the differences between the excitation energies of isobaric analog states in the same nucleus. Numerous such excitation energies are known exper- imentally

  10. Efficient Method for Magnitude Comparison in RNS Based on Two Pairs of Conjugate Moduli

    E-Print Network [OSTI]

    Sousa, Leonel

    Efficient Method for Magnitude Comparison in RNS Based on Two Pairs of Conjugate Moduli Leonel (RNS) is very useful to achieve carry free arithmetic. How- ever it makes the comparison of numbers method for magnitude comparison in RNS. Moreover, magnitude comparison for RNS that rely on pairs

  11. Methods and compositions for the production of orthogonal tRNA-aminoacyl-tRNA synthetase pairs

    DOE Patents [OSTI]

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

    2011-09-06

    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.

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

    DOE Patents [OSTI]

    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)

    2008-04-08

    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.

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

    DOE Patents [OSTI]

    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)

    2012-05-22

    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.

  14. High-Speed Software Implementation of the Optimal Ate Pairing over BarretoNaehrig

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    High-Speed Software Implementation of the Optimal Ate Pairing over Barreto­Naehrig Curves Jean-0052 Abstract. This paper describes the design of a fast software library for the computation of the optimal ate, finite field arithmetic, bilinear pairing software implementation. 1 Introduction The protocol solutions

  15. MULTI-DIMENSIONAL SIMULATIONS OF ROTATING PAIR-INSTABILITY SUPERNOVAE

    SciTech Connect (OSTI)

    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)

    2013-10-20

    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.

  16. Microscopic linear response calculations based on the Skyrme functional plus the pairing contribution

    E-Print Network [OSTI]

    Jun Li; Gianluca Colo'; Jie Meng

    2008-11-25

    A self-consistent Quasiparticle-Random-Phase-Approximation (QRPA) model which employs the canonical Hartree-Fock-Bogoliubov (HFB) basis and an energy-density functional with a Skyrme mean field part and a density-dependent pairing, is used to study the monopole collective excitations of spherical even-even nuclei. The influence of the spurious state on the strength function of the isoscalar monopole excitations is clearly assessed. We compare the effect of different kinds of pairing forces (volume pairing, surface pairing and mixed pairing) on the monopole excitation strength function. The energy of the Isoscalar Giant Monopole Resonance (ISGMR), which is related to the nuclear incompressibility $K_{\\infty}$, is calculated for tin isotopes and the results are discussed.

  17. A weak-value interpretation of the Schwinger mechanism of massless/massive pair productions

    E-Print Network [OSTI]

    Kazuhiro Yokota; Nobuyuki Imoto

    2015-04-28

    According to the Schwinger mechanism, a uniform electric field brings about pair productions in vacuum; the relationship between the production rate and the electric field is different, depending on the dimension of the system. In this paper, we make an offer of another model for the pair productions, in which weak values are incorporated: energy fluctuations trigger the pair production, and a weak value appears as the velocity of a particle there. Although our model is only available for the approximation of the pair production rates, the weak value reveals a new aspect of the pair production. Especially, within the first order, our estimation approximately agrees with the exponential decreasing rate of the Landau-Zener tunneling through the mass energy gap. In other words, such tunneling can be associated with energy fluctuations via the weak value, when the tunneling gap can be regarded as so small due to the high electric field.

  18. Competition between magnetic and superconducting pairing exchange interactions in confined systems

    SciTech Connect (OSTI)

    Ying Zujian; Cuoco, Mario; Noce, Canio; Zhou Huanqiang

    2007-10-01

    We analyze the competition between magnetic and pairing interactions in confined systems relevant to either small superconducting grains or trapped ultracold atomic gases. The response to the imbalance of the chemical potential for the two spin states leads to various inhomogeneous profiles of the pair energy distribution. We show that the position in the energy spectrum for the unpaired particles can be tuned by varying the filling or the pairing strength. When small grains are considered, the antiferromagnetic exchange stabilizes the pair correlations, whereas for Fermi gases, a transition from a mixed configuration to a phase-separated one beyond a critical polarization threshold appears, as does an unconventional phase with a paired shell around a normal core.

  19. One-Photon Mass-Analyzed Threshold Ionization Spectroscopy of Bis(6-benzene)chromium and Its Benzene and Ar Clusters

    E-Print Network [OSTI]

    Kim, Sang Kyu

    One-Photon Mass-Analyzed Threshold Ionization Spectroscopy of Bis(6-benzene)chromium and Its Benzene and Ar Clusters Kyo-Won Choi and Sang Kyu Kim* Department of Chemistry and School of Molecular-analyzed threshold ionization (MATI) spectroscopy of bis(6-benzene)chromium is reported. The adiabatic ionization

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

    E-Print Network [OSTI]

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

    2001-07-19

    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.

  1. Ionization of large homogeneous and heterogeneous clusters generated in acetylene-Ar expansions: Cluster ion polymerization

    SciTech Connect (OSTI)

    Kocisek, J.; Lengyel, J.; Farnik, M.

    2013-03-28

    Pure acetylene and mixed Ar-acetylene clusters are formed in supersonic expansions of acetylene/argon mixtures and analysed using reflectron time-of-flight mass spectrometer with variable electron energy ionization source. Acetylene clusters composed of more than a hundred acetylene molecules are generated at the acetylene concentration of Almost-Equal-To 8%, while mixed species are produced at low concentrations ( Almost-Equal-To 0.7%). The electron energy dependence of the mass spectra revealed the ionization process mechanisms in clusters. The ionization above the threshold for acetylene molecule of 11.5 eV results in the main ionic fragment progression (C{sub 2}H{sub 2}){sub n}{sup +}. At the electron energies Greater-Than-Or-Slanted-Equal-To 21.5 eV above the CH+CH{sup +} dissociative ionization limit of acetylene the fragment ions nominally labelled as (C{sub 2}H{sub 2}){sub n}CH{sup +}, n Greater-Than-Or-Slanted-Equal-To 2, are observed. For n Less-Than-Or-Slanted-Equal-To 7 these fragments correspond to covalently bound ionic structures as suggested by the observed strong dehydrogenation [(C{sub 2}H{sub 2}){sub n}-k Multiplication-Sign H]{sup +} and [(C{sub 2}H{sub 2}){sub n}CH -k Multiplication-Sign H]{sup +}. The dehydrogenation is significantly reduced in the mixed clusters where evaporation of Ar instead of hydrogen can stabilize the nascent molecular ion. The C{sub 3}H{sub 3}{sup +} ion was previously assigned to originate from the benzene molecular ion; however, the low appearance energy of Almost-Equal-To 13.7 eV indicates that a less rigid covalently bound structure of C{sub 6}H{sub 6}{sup +} ion must also be formed upon the acetylene cluster electron ionization. The appearance energy of Ar{sub n}(C{sub 2}H{sub 2}){sup +} fragments above Almost-Equal-To 15.1 eV indicates that the argon ionization is the first step in the fragment ion production, and the appearance energy of Ar{sub n{>=}2}(C{sub 2}H{sub 2}){sub m{>=}2}{sup +} at Almost-Equal-To 13.7 eV is discussed in terms of an exciton transfer mechanism.

  2. Coherent chemical kinetics as quantum walks I: Reaction operators for radical pairs

    E-Print Network [OSTI]

    A. Chia; A. Gorecka; K. C. Tan; L. Pawela; P. Kurzynski; T. Paterek; D. Kaszlikowski

    2015-06-13

    Classical chemical kinetics use rate-equation models to describe how a reaction proceeds in time. Such models are sufficient for describing state transitions in a reaction where coherences between different states do not arise, or in other words, a reaction which contain only incoherent transitions. A prominent example reaction containing coherent transitions is the radical-pair model. The kinetics of such reactions is defined by the so-called reaction operator which determines the radical-pair state as a function of intermediate transition rates. We argue that the well-known concept of quantum walks from quantum information theory is a natural and apt framework for describing multisite chemical reactions. By composing Kraus maps that act only on two sites at a time, we show how the quantum-walk formalism can be applied to derive a reaction operator for the standard avian radical-pair reaction. Our reaction operator predicts a recombination dephasing rate consistent with recent experiments [J. Chem. Phys. {\\bf 139}, 234309 (2013)], in contrast to previous work by Jones and Hore [Chem. Phys. Lett. {\\bf 488}, 90 (2010)]. The standard radical-pair reaction has conventionally been described by either a normalised density operator incorporating both the radical pair and reaction products, or by a trace-decreasing density operator that considers only the radical pair. We demonstrate a density operator that is both normalised and refers only to radical-pair states. Generalisations to include additional dephasing processes and an arbitrary number of sites are also discussed.

  3. Optical flashes from internal pairs formed in gamma-ray burst afterglows

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

    Panaitescu, A.

    2015-06-09

    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 gamma-ray burst (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 somemore »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 ($R\\lt 10$) lasting for up to one hundred seconds. As a result, the number of internal pairs formed from unscattered seed photons decreases very strongly with the source Lorentz factor, thus bright GRB optical counterparts cannot arise from internal pairs if the afterglow Lorentz factor is above several hundreds.« less

  4. Coherent chemical kinetics as quantum walks I: Reaction operators for radical pairs

    E-Print Network [OSTI]

    A. Chia; A. Gorecka; K. C. Tan; L. Pawela; P. Kurzynski; T. Paterek; D. Kaszlikowski

    2015-08-20

    Classical chemical kinetics use rate-equation models to describe how a reaction proceeds in time. Such models are sufficient for describing state transitions in a reaction where coherences between different states do not arise, or in other words, a reaction which contain only incoherent transitions. A prominent example reaction containing coherent transitions is the radical-pair model. The kinetics of such reactions is defined by the so-called reaction operator which determines the radical-pair state as a function of intermediate transition rates. We argue that the well-known concept of quantum walks from quantum information theory is a natural and apt framework for describing multisite chemical reactions. By composing Kraus maps that act only on two sites at a time, we show how the quantum-walk formalism can be applied to derive a reaction operator for the standard avian radical-pair reaction. Our reaction operator predicts a recombination dephasing rate consistent with recent experiments [J. Chem. Phys. {\\bf 139}, 234309 (2013)], in contrast to previous work by Jones and Hore [Chem. Phys. Lett. {\\bf 488}, 90 (2010)]. The standard radical-pair reaction has conventionally been described by either a normalised density operator incorporating both the radical pair and reaction products, or by a trace-decreasing density operator that considers only the radical pair. We demonstrate a density operator that is both normalised and refers only to radical-pair states. Generalisations to include additional dephasing processes and an arbitrary number of sites are also discussed.

  5. Theory of nodal s±-wave pairing symmetry in the Pu-based 115 superconductor family

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

    Das, Tanmoy; Zhu, Jian -Xin; Graf, Matthias J.

    2015-02-27

    The spin-fluctuation mechanism of superconductivity usually results in the presence of gapless or nodal quasiparticle states in the excitation spectrum. Nodal quasiparticle states are well established in copper-oxide, and heavy-fermion superconductors, but not in iron-based superconductors. Here, we study the pairing symmetry and mechanism of a new class of plutonium-based high-Tc superconductors and predict the presence of a nodal s?? wave pairing symmetry in this family. Starting from a density-functional theory (DFT) based electronic structure calculation we predict several three-dimensional (3D) Fermi surfaces in this 115 superconductor family. We identify the dominant Fermi surface “hot-spots” in the inter-band scattering channel,more »which are aligned along the wavevector Q = (?, ?, ?), where degeneracy could induce sign-reversal of the pairing symmetry. Our calculation demonstrates that the s?? wave pairing strength is stronger than the previously thought d-wave pairing; and more importantly, this pairing state allows for the existence of nodal quasiparticles. Finally, we predict the shape of the momentum- and energy-dependent magnetic resonance spectrum for the identification of this pairing symmetry.« less

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

    SciTech Connect (OSTI)

    Poswal, A. K.; Agrawal, A.; Bhattachryya, D.; Jha, S. N.; Sahoo, N. K.

    2013-02-05

    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.

  7. Distribution of Primes and of Interval Prime Pairs Based on $?$ Function

    E-Print Network [OSTI]

    Yifang Fan; Zhiyu Li

    2010-04-19

    $\\Theta$ function is defined based upon Kronecher symbol. In light of the principle of inclusion-exclusion, $\\Theta$ function of sine function is used to denote the distribution of composites and primes. The structure of Goldbach Conjecture has been analyzed, and $\\Xi$ function is brought forward by the linear diophantine equation; by relating to $\\Theta$ function, the interval distribution of composite pairs and prime pairs (i.e. the Goldbach Conjecture) is thus obtained. In the end, Abel's Theorem (Multiplication of Series) is used to discuss the lower limit of the distribution of the interval prime pairs.

  8. The influence of pairing correlations on the isospin symmetry breaking corrections of superallowed Fermi beta decays

    SciTech Connect (OSTI)

    Cal Latin-Small-Letter-Dotless-I k, A. E.; Gerceklioglu, M.; Selam, C.

    2013-05-15

    Within the framework of quasi-particle random phase approximation, the isospin breaking correction of superallowed 0{sup +} {yields} 0{sup +} beta decay and unitarity of Cabibbo-Kobayashi-Maskawa mixing matrix have been investigated. The broken isotopic symmetry of nuclear part of Hamiltonian has been restored by Pyatov's method. The isospin symmetry breaking correction with pairing correlations has been compared with the previous results without pairing. The effect of pairing interactions has been examined for nine superallowed Fermi beta decays; their parent nuclei are {sup 26}Al, {sup 34}Cl, {sup 38}K, {sup 42}Sc, {sup 46}V, {sup 50}Mn, {sup 54}Co, {sup 62}Ga, {sup 74}Rb.

  9. Irradiation test on FD-SOI Readout ASIC of Pair-monitor

    E-Print Network [OSTI]

    Yutaro Sato; Hirokazu Ikeda; Akiya Miyamoto; Yosuke Takubo; Toshiaki Tauchi; Hitoshi Yamamoto

    2010-06-22

    We fabricated a readout ASIC with the fully depleted silicon-on-insulator (FD-SOI) technology for the pair-monitor. The pair-monitor is a silicon pixel device that measures the beam profile of the international linear collider. It utilizes the directional distribution of a large number of electron-positron pairs created by collision of bunches, and is required to tolerate radiation dose of about a few Mrad/year. The irradiation might cause the buried oxide layer of SOI to accumulate charges which interfere with intended functions. We thus performed extensive irradiation tests on the prototype ASIC, and the results are described in this paper.

  10. Nano-scale electron bunching in laser-triggered ionization injection in plasma accelerators

    E-Print Network [OSTI]

    Xu, X L; Li, F; Wan, Y; Wu, Y P; Hua, J F; Pai, C -H; Lu, W; An, W; Yu, P; Mori, W B; Joshi, C

    2015-01-01

    Ionization injection is attractive as a controllable injection scheme for generating high quality electron beams using plasma-based wakefield acceleration. Due to the phase dependent tunneling ionization rate and the trapping dynamics within a nonlinear wake, the discrete injection of electrons within the wake is nonlinearly mapped to discrete final phase space structure of the beam at the location where the electrons are trapped. This phenomenon is theoretically analyzed and examined by three-dimensional particle-in-cell simulations which show that three dimensional effects limit the wave number of the modulation to between $> 2k_0$ and about $5k_0$, where $k_0$ is the wavenumber of the injection laser. Such a nano-scale bunched beam can be diagnosed through coherent transition radiation upon its exit from the plasma and may find use in generating high-power ultraviolet radiation upon passage through a resonant undulator.

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

    SciTech Connect (OSTI)

    Hart, T. L.

    2010-03-30

    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%.

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

    SciTech Connect (OSTI)

    Jayasekharan, T.; Sahoo, N. K.

    2013-02-05

    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.

  13. Ionization-Enhanced Decomposition of 2,4,6-Trinitrotoluene (TNT) Molecules

    SciTech Connect (OSTI)

    Wang, Bin [Vanderbilt University; Wright, David [Vanderbilt University; Cliffel, David [Vanderbilt University; HaglundJr., Richard F [Vanderbilt University; Pantelides, Sokrates T. [Vanderbilt University

    2011-01-01

    The unimolecular decomposition reaction of TNT can in principle be used to design ways to either detect or remove TNT from the environment. Here, we report the results of a density functional theory study of possible ways to lower the reaction barrier for this decomposition process by ionization, so that decomposition and/or detection can occur at room temperature. We find that ionizing TNT lowers the reaction barrier for the initial step of this decomposition. We further show that a similar effect can occur if a positive moiety is bound to the TNT molecule. The positive charge produces a pronounced electron redistribution and dipole formation in TNT with minimal charge transfer from TNT to the positive moiety.

  14. Ionization avalanching in clusters ignited by extreme-ultraviolet driven seed electrons

    E-Print Network [OSTI]

    Schütte, Bernd; Mermillod-Blondin, Alexandre; Vrakking, Marc J J; Rouzée, Arnaud; Fennel, Thomas

    2015-01-01

    We study the ionization dynamics of Ar clusters exposed to ultrashort near-infrared (NIR) laser pulses for intensities well below the threshold at which tunnel ionization could ignite the nanoplasma formation. We find that the emission of highly charged ions up to Ar$^{8+}$ can be switched on with unit contrast by generating only a few seed electrons with an ultrashort extreme ultraviolet (XUV) pulse prior to the NIR field. Molecular dynamics simulations can explain the experimental observations and predict a generic scenario where efficient heating via inverse bremsstrahlung and NIR avalanching are followed by resonant collective nanoplasma heating. The temporally and spatially well-controlled injection of the XUV seed electrons opens new routes for controlling avalanching and heating phenomena in nanostructures and solids, with implications for both fundamental and applied laser-matter science.

  15. High-resolution ion pulse ionization chamber with air filling for the Rn-222 decays detection

    E-Print Network [OSTI]

    Gavrilyuk, Yu M; Gezhaev, A M; Etezov, R A; Kazalov, V V; Kuzminov, V V; Panasenko, S I; Ratkevich, S S; Tekueva, D A; Yakimenko, S P

    2015-01-01

    The construction and characteristics of the cylindrical ion pulse ionization chamber (CIPIC) with a working volume of 3.2 L are described. The chamber is intended to register alpha-particles from the $^{222}$Rn and its daughter's decays in the filled air sample. The detector is less sensitive to electromagnetic pick-ups and mechanical noises. The digital pulse processing method is proposed to improve the energy resolution of the ion pulse ionization chamber. An energy resolution of 1.6% has been achieved for the 5.49 MeV alpha-line. The dependence of the energy resolution on high voltage and working media pressure has been investigated and the results are presented.

  16. Photoassociation spectroscopy in Penning ionization reactions at sub-Kelvin temperatures

    E-Print Network [OSTI]

    Skomorowski, Wojciech; Narevicius, Edvardas; Koch, Christiane P

    2016-01-01

    Penning ionization reactions in merged beams with precisely controlled collision energies have been shown to accurately probe quantum mechanical effects in reactive collisions. A complete microscopic understanding of the reaction is, however, faced with two major challenges---the highly excited character of the reaction's entrance channel and the limited precision of even the best state-of-the-art ab initio potential energy surfaces. Here, we suggest photoassociation spectroscopy as a tool to identify the character of orbiting resonances in the entrance channel and probe the ionization width as a function of inter-particle separation. We introduce the basic concept and discuss the general conditions under which this type of spectroscopy will be successful.

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

    SciTech Connect (OSTI)

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

    2014-02-04

    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.

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

    DOE Patents [OSTI]

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

    2006-07-18

    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.

  19. Multireference configuration interaction calculations of the first six ionization potentials of the uranium atom

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

    Bross, David H.; Parmar, Payal; Peterson, Kirk A.

    2015-11-12

    The first 6 ionization potentials (IPs) of the uranium atom have been calculated using multireference configuration interaction (MRCI+Q) with extrapolations to the complete basis set (CBS) limit using new all-electron correlation consistent basis sets. The latter were carried out with the third-order Douglas-Kroll-Hess Hamiltonian. Correlation down through the 5s5p5d electrons have been taken into account, as well as contributions to the IPs due to the Lamb shift. Spin-orbit coupling contributions calculated at the 4-component Kramers restricted configuration interaction level, as well as the Gaunt term computed at the Dirac-Hartree-Fock level, were added to the best scalar relativistic results. As amore »result, the final ionization potentials are expected to be accurate to at least 5 kcal/mol (0.2 eV), and thus more reliable than the current experimental values of IP3 through IP6.« less

  20. Velocity Profile of the Ionized Disk and the Mass of the Black Hole in M87

    E-Print Network [OSTI]

    Sandip K. Chakrabarti

    1994-11-10

    We present a theoretical model for the ionized disk in M87 which includes spiral shock waves. The line emission profiles computed from this model at various positions on the disk are found to be in agreement with the recent Hubble Space Telescope results. Based on this model, we find that the ionized disk comprises two-armed giant spiral shock waves which extend from around $0.1$ arc sec from the center to at least $1$ arc second or more. Our model requires that the mass of the black hole be $(4 \\pm 0.2) \\times 10^9 M_\\odot$ and the inclination angle to be $(42\\pm 2)^{\\deg}$. We predict the nature of the line profiles at many other locations of the disk which could be verified in future observations.

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

    SciTech Connect (OSTI)

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

    1993-03-01

    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.

  2. Ionization-induced annealing of pre-existing defects in silicon carbide

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

    Zhang, Yanwen; Sachan, Ritesh; Pakarinen, Olli H; Chisholm, Matthew F; Liu, Peng; Xue, Haizhou; Weber, William J

    2015-01-01

    A long-standing objective in materials research is to find innovative ways to remove preexisting damage and heal fabrication defects or environmentally induced defects in materials. Silicon carbide (SiC) is a fascinating wide-band gap semiconductor for high-temperature, high-power, high-frequency applications. Its high corrosion and radiation resistance makes it a key refractory/structural material with great potential for extremely harsh radiation environments. Here we show that the energy transferred to the electron system of SiC by energetic ions via inelastic ionization processes results in a highly localized thermal spike that can effectively heal preexisting defects and restore the structural order. This work revealsmore »an innovative self-healing process using highly ionizing ions, and it describes a critical aspect to be considered in modeling SiC performance as either a functional or a structural material for device applications or high-radiation environments.« less

  3. Ionization of oriented carbonyl-sulfide molecules by intense circularly polarized laser pulses

    E-Print Network [OSTI]

    Dimitrovski, Darko; Madsen, Lars Bojer; Filsinger, Frank; Meijer, Gerard; Küpper, Jochen; Holmegaard, Lotte; Kalhøj, Line; Nielsen, Jens H; Stapelfeldt, Henrik

    2010-01-01

    We present combined experimental and theoretical results on strong-field ionization of oriented carbonyl-sulphide molecules by circularly-polarized laser pulses. The obtained molecular frame photoelectron angular distributions show pronounced asymmetries perpendicular to the direction of the molecular electric dipole moment. These findings are explained by a tunneling model invoking the laser-induced Stark shifts associated with the dipoles and polarizabilities of the molecule and its unrelaxed cation.

  4. The iQID Camera An Ionizing-Radiation Quantum Imaging Detector

    SciTech Connect (OSTI)

    Miller, Brian W.; Gregory, Stephanie J.; Fuller, Erin S.; Barrett, Harrison H.; Barber, Bradford H.; Furenlid, Lars R.

    2014-06-11

    Abstract We have developed and tested a novel, ionizing-radiation Quantum Imaging Detector (iQID). This scintillation-based detector was originally developed as a high-resolution gamma-ray imager, called BazookaSPECT, for use in single-photon emission computed tomography (SPECT). Recently, we have investigated the detectors response and imaging potential with other forms of ionizing radiation including alpha, neutron, beta, and fission fragment particles. The detector’s response to a broad range of ionizing radiation has prompted its new title. The principle operation of the iQID camera involves coupling a scintillator to an image intensifier. The scintillation light generated particle interactions is optically amplified by the intensifier and then re-imaged onto a CCD/CMOS camera sensor. The intensifier provides sufficient optical gain that practically any CCD/CMOS camera can be used to image ionizing radiation. Individual particles are identified and their spatial position (to sub-pixel accuracy) and energy are estimated on an event-by-event basis in real time using image analysis algorithms on high-performance graphics processing hardware. Distinguishing features of the iQID camera include portability, large active areas, high sensitivity, and high spatial resolution (tens of microns). Although modest, iQID has energy resolution that is sufficient to discrimate between particles. Additionally, spatial features of individual events can be used for particle discrimination. An important iQID imaging application that has recently been developed is single-particle, real-time digital autoradiography. We present the latest results and discuss potential applications.

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

    SciTech Connect (OSTI)

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

    1981-01-01

    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.

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

    DOE Patents [OSTI]

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

    2010-03-02

    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.

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

    DOE Patents [OSTI]

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

    2012-05-08

    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.

  8. Apparatus and method for the simultaneous detection of neutrons and ionizing electromagnetic radiation

    DOE Patents [OSTI]

    Bell, Zane W. (Oak Ridge, TN)

    2000-01-01

    A sensor for simultaneously detecting neutrons and ionizing electromagnetic radiation comprising: a sensor for the detection of gamma radiation, the sensor defining a sensing head; the sensor further defining an output end in communication with the sensing head; and an exterior neutron-sensitive material configured to form around the sensing head; wherein the neutron-sensitive material, subsequent to the capture of the neutron, fissions into an alpha-particle and a .sup.7 Li ion that is in a first excited state in a majority of the fissions, the first excited state decaying via the emission of a single gamma ray at 478 keV which can in turn be detected by the sensing head; and wherein the sensing head can also detect the ionizing electromagnetic radiation from an incident radiation field without significant interference from the neutron-sensitive material. A method for simultaneously detecting neutrons and ionizing electromagnetic radiation comprising the steps of: providing a gamma ray sensitive detector comprising a sensing head and an output end; conforming an exterior neutron-sensitive material configured to form around the sensing head of the detector; capturing neutrons by the sensing head causing the neutron-sensitive material to fission into an alpha-particle and a .sup.7 Li ion that is in a first excited state in a majority of the fissions, the state decaying via the emission of a single gamma ray at 478 keV; sensing gamma rays entering the detector through the neutron-sensitive material; and producing an output through a readout device coupled to the output end; wherein the detector provides an output which is proportional to the energy of the absorbed ionizing electromagnetic radiation.

  9. 3D spectroscopy of the ionized gas kinematics in galactic rings

    E-Print Network [OSTI]

    Moiseev, A V

    2008-01-01

    The kinematics of galactic rings were studied with a scanning Fabry-Perot interferometer mounted in the multi-mode focal reducer SCORPIO (Afanasiev & Moiseev 2005) at the SAO RAS 6-m telescope. The analysis of the ionized gas velocity fields allows us to understand the nature of the ring formation in several galaxies. The different types of the rings in the presented objects (resonanced, collisional, polar) were caused by the various sorts of interactions: merging, head-on collisions.

  10. 3D spectroscopy of the ionized gas kinematics in galactic rings

    E-Print Network [OSTI]

    A. V. Moiseev

    2008-01-10

    The kinematics of galactic rings were studied with a scanning Fabry-Perot interferometer mounted in the multi-mode focal reducer SCORPIO (Afanasiev & Moiseev 2005) at the SAO RAS 6-m telescope. The analysis of the ionized gas velocity fields allows us to understand the nature of the ring formation in several galaxies. The different types of the rings in the presented objects (resonanced, collisional, polar) were caused by the various sorts of interactions: merging, head-on collisions.

  11. Atomic ionization by keV-scale pseudoscalar dark-matter particles

    SciTech Connect (OSTI)

    Dzuba, V. A.; Flambaum, V. V.; Pospelov, M.

    2010-05-15

    Using the relativistic Hartree-Fock approximation, we calculate the rates of atomic ionization by absorption of pseudoscalar particles in the mass range from 10 to {approx}50 keV. We present numerical results for atoms relevant for the direct dark-matter searches (e.g. Ar, Ge, I and Xe), as well as the analytical formula which fits numerical calculations with few per cent accuracy and may be used for multielectron atoms, molecules and condensed matter systems.

  12. Real-time monitoring of volatile organic compounds using chemical ionization mass spectrometry

    DOE Patents [OSTI]

    Mowry, Curtis Dale (Albuquerque, NM); Thornberg, Steven Michael (Peralta, NM)

    1999-01-01

    A system for on-line quantitative monitoring of volatile organic compounds (VOCs) includes pressure reduction means for carrying a gaseous sample from a first location to a measuring input location maintained at a low pressure, the system utilizing active feedback to keep both the vapor flow and pressure to a chemical ionization mode mass spectrometer constant. A multiple input manifold for VOC and gas distribution permits a combination of calibration gases or samples to be applied to the spectrometer.

  13. Escape fraction of ionizing photons during reionization: Effects due to supernova feedback and runaway ob stars

    SciTech Connect (OSTI)

    Kimm, Taysun; Cen, Renyue [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton, NJ 08544 (United States)

    2014-06-20

    The fraction of hydrogen ionizing photons escaping from galaxies into the intergalactic medium is a critical ingredient in the theory of reionization. We use two zoomed-in, high-resolution (4 pc), cosmological radiation hydrodynamic simulations with adaptive mesh refinement to investigate the impact of two physical mechanisms (supernova, SN, feedback, and runaway OB stars) on the escape fraction (f {sub esc}) at the epoch of reionization (z ? 7). We implement a new, physically motivated SN feedback model that can approximate the Sedov solutions at all (from the free expansion to snowplow) stages. We find that there is a significant time delay of about ten million years between the peak of star formation and that of escape fraction, due to the time required for the build-up and subsequent destruction of the star-forming cloud by SN feedback. Consequently, the photon number-weighted mean escape fraction for dwarf galaxies in halos of mass 10{sup 8}-10{sup 10.5} M {sub ?} is found to be ?f{sub esc}??11%, although instantaneous values of f {sub esc} > 20% are common when star formation is strongly modulated by the SN explosions. We find that the inclusion of runaway OB stars increases the mean escape fraction by 22% to ?f{sub esc}??14%. As SNe resulting from runaway OB stars tend to occur in less dense environments, the feedback effect is enhanced and star formation is further suppressed in halos with M{sub vir}?10{sup 9} M{sub ?} in the simulation with runaway OB stars compared with the model without them. While both our models produce enough ionizing photons to maintain a fully ionized universe at z ? 7 as observed, a still higher amount of ionizing photons at z ? 9 appears necessary to accommodate the high observed electron optical depth inferred from cosmic microwave background observations.

  14. Selective Strong-Field Enhancement and Attenuation of Excitation and Ionization with Short Laser Pulses 

    E-Print Network [OSTI]

    Hart, Nathan Andrew

    2015-05-12

    Nathan Hart Advisor: Dr. Hans Schuessler Selective Strong-Field Excitation and Ionization with Short Laser Pulses Introduction … In this research, we: 1. Experimentally demonstrate coherent control of atomic energy level population in sodium... Sampling. 4. Directly measure the ponderomotive shift of the continuum. 5. Identify Freeman resonances as the dominant means of atomic excitation in high intensity laser fields Nathan Hart Experimental Apparatus • Pulses from a Ti:Sapphire oscillator...

  15. Temperature fluctuations in HII regions: ionization by Cosmic Rays as a key mechanism

    E-Print Network [OSTI]

    C. Giammanco; J. E. Beckman

    2005-05-18

    We present a detailed model capable of explaining quantitatively the temperature fluctuations observed in luminous, large HII regions. The model is based on two assumptions which we justify on the basis of observations: that the major fraction of the hydrogen in the clouds that form the HII regions is not photoionized and is essentially HI, this HII is lightly ionized by fluxes of low energy cosmic rays (CR) produced by processes originating in the hot stars which illuminate the regions.

  16. Dwarf galaxies with ionizing radiation feedback. II. Spatially resolved star formation relation

    SciTech Connect (OSTI)

    Kim, Ji-hoon; Krumholz, Mark R.; Goldbaum, Nathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Wise, John H. [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Turk, Matthew J. [Department of Astronomy and Astrophysics, Columbia University, New York, NY 10027 (United States); Abel, Tom, E-mail: me@jihoonkim.org [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States)

    2013-12-10

    We investigate the spatially resolved star formation relation using a galactic disk formed in a comprehensive high-resolution (3.8 pc) simulation. Our new implementation of stellar feedback includes ionizing radiation as well as supernova explosions, and we handle ionizing radiation by solving the radiative transfer equation rather than by a subgrid model. Photoheating by stellar radiation stabilizes gas against Jeans fragmentation, reducing the star formation rate (SFR). Because we have self-consistently calculated the location of ionized gas, we are able to make simulated, spatially resolved observations of star formation tracers, such as H? emission. We can also observe how stellar feedback manifests itself in the correlation between ionized and molecular gas. Applying our techniques to the disk in a galactic halo of 2.3 × 10{sup 11} M {sub ?}, we find that the correlation between SFR density (estimated from mock H? emission) and H{sub 2} density shows large scatter, especially at high resolutions of ?75 pc that are comparable to the size of giant molecular clouds (GMCs). This is because an aperture of GMC size captures only particular stages of GMC evolution and because H? traces hot gas around star-forming regions and is displaced from the H{sub 2} peaks themselves. By examining the evolving environment around star clusters, we speculate that the breakdown of the traditional star formation laws of the Kennicutt-Schmidt type at small scales is further aided by a combination of stars drifting from their birthplaces and molecular clouds being dispersed via stellar feedback.

  17. Modeling heavy ion ionization energy loss at low and intermediate energies

    SciTech Connect (OSTI)

    Rakhno, I.L.; /Fermilab

    2009-11-01

    The needs of contemporary accelerator and space projects led to significant efforts made to include description of heavy ion interactions with matter in general-purpose Monte Carlo codes. This paper deals with an updated model of heavy ion ionization energy loss developed previously for the MARS code. The model agrees well with experimental data for various projectiles and targets including super-heavy ions in low-Z media.

  18. SEARCH FOR IONIZED JETS TOWARD HIGH-MASS YOUNG STELLAR OBJECTS

    SciTech Connect (OSTI)

    Guzman, Andres E.; Garay, Guido; Brooks, Kate J.; Voronkov, Maxim A.

    2012-07-01

    We are carrying out multi-frequency radio continuum observations, using the Australia Telescope Compact Array, to systematically search for collimated ionized jets toward high-mass young stellar objects (HMYSOs). Here we report observations at 1.4, 2.4, 4.8, and 8.6 GHz, made with angular resolutions of about 7'', 4'', 2'', and 1'', respectively, toward six objects of a sample of 33 southern HMYSOs thought to be in very early stages of evolution. The objects in the sample were selected from radio and infrared catalogs by having positive radio spectral indices and being luminous (L{sub bol} > 2 Multiplication-Sign 10{sup 4} L{sub Sun }), but underluminous in radio emission compared with that expected from its bolometric luminosity. This criterion makes the radio sources good candidates for being ionized jets. As part of this systematic search, two ionized jets have been discovered: one previously published and the other reported here. The rest of the observed candidates correspond to three hypercompact H II regions and two ultracompact H II regions. The two jets discovered are associated with two of the most luminous (7 Multiplication-Sign 10{sup 4} and 1.0 Multiplication-Sign 10{sup 5} L{sub Sun }) HMYSOs known to harbor this type of object, showing that the phenomena of collimated ionized winds appear in the formation process of stars at least up to masses of {approx}20 M{sub Sun} and provide strong evidence for a disk-mediated accretion scenario for the formation of high-mass stars. From the incidence of jets in our sample, we estimate that the jet phase in high-mass protostars lasts for {approx}4 Multiplication-Sign 10{sup 4} yr.

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

    E-Print Network [OSTI]

    Gomez Hernandez, Mario 1980-

    2012-07-11

    -MS Matrix Assisted Laser Desorption Ionization Mass Spectrometry AuNPs Gold Nanoparticles UV-Vis Ultraviolet-Visible Spectroscopy TEM Transmission Electron Microscopy NMR Nuclear Magnetic Resonance Spectroscopy RIY Relative Ion... including enhanced Rayleigh scattering,2 biological reaction catalysis,3 aggregation assays,4 surface enhanced Raman spectroscopy,5 and other applications known as nanobiotechnology.6 Therefore, it is the combination of the proven performance of mass...

  20. Electron residual energy due to stochastic heating in field-ionized plasma

    E-Print Network [OSTI]

    Khalilzadeh, Elnaz; Jahanpanah, Jafar; Chakhmachi, Amir; Yazdani, Elnaz

    2015-01-01

    The electron residual energy originated from the stochastic heating in under-dense field-ionized plasma is here investigated. The optical response of plasma is initially modeled by using the concept of two counter-propagating electromagnetic waves. The solution of motion equation of a single electron indicates that by including the ionization, the electron with higher residual energy compared to the case without ionization could be obtained. In agreement with chaotic nature of the motion, it is found that the electron residual energy will significantly be changed by applying a minor change to the initial conditions. Extensive kinetic 1D-3V particle-in-cell (PIC) simulations have been performed in order to resolve full plasma reactions. In this way, two different regimes of plasma behavior are observed by varying the pulse length. The results indicate that the amplitude of scattered fields in sufficient long pulse length is high enough to act as a second counter-propagating wave for triggering the stochastic e...