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Note: This page contains sample records for the topic "ionization brems pair" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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1

Ionizing Radiation  

Science Conference Proceedings (OSTI)

*. Bookmark and Share. Ionizing Radiation Measurements. Fees for services are located directly below the technical contacts ...

2013-04-09T23:59:59.000Z

2

Soft ionization of thermally evaporated hypergolic ionic liquid aerosols  

E-Print Network (OSTI)

+ ][Dca ? ]. Figure 2. Aerosol particle size distribution ofhypergolic ionic liquid aerosols Christine J. Koh † , Chen-ionization of evaporated IL aerosols Isolated ion pairs of a

Koh, Christine J.

2013-01-01T23:59:59.000Z

3

Table  

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

Muons in Lithium oxide Li 2 O ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.46952 2.013 73.6 0.08035 3.7878 -0.0511 2.5874 2.9340 0.00 T p Ionization Brems Pair prod Photonucl...

4

Table  

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

Muons in Lithium tetraborate Li 2 B 4 O 7 ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.48487 2.440 94.6 0.11075 3.4389 0.0737 2.6502 3.2093 0.00 T p Ionization Brems Pair...

5

Table  

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

Muons in Lithium carbonate (Li 2 C-O 3 ) ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.49720 2.110 87.9 0.09936 3.5417 0.0551 2.6598 3.2029 0.00 T p Ionization Brems Pair prod...

6

Table  

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

Muons in Lithium iodide (LiI) ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.41939 3.494 485.1 0.23274 2.7146 0.0892 3.3702 6.2671 0.00 T p Ionization Brems Pair prod Photonucl...

7

Table  

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

Muons in Lithium amide (LiNH 2 ) ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.52257 1.178 55.5 0.08740 3.7534 0.0198 2.5152 2.7961 0.00 T p Ionization Brems Pair prod...

8

Table  

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

Muons in Lithium Z A gmol gcm 3 I eV a k m s x 0 x 1 C 0 3 (Li) 6.941 (2) 0.534 40.0 0.95136 2.4993 0.1304 1.6397 3.1221 0.14 T p Ionization Brems Pair prod...

9

Table  

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

Muons in Lithium hydride (LiH) ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.50321 0.820 36.5 0.90567 2.5849 -0.0988 1.4515 2.3580 0.00 T p Ionization Brems Pair prod...

10

Table  

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

sucrose ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.55014 1.070 74.2 0.09143 3.4982 0.2187 2.7680 3.4216 0.00 T p Ionization Brems Pair prod Photonucl Total CSDA range...

11

Table  

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

fluoride (CsF) ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.42132 4.115 440.7 0.22052 2.7280 0.0084 3.3374 5.9046 0.00 T p Ionization Brems Pair prod Photonucl Total CSDA...

12

Table  

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

fluoride MgF 2 ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.48153 3.000 134.3 0.07934 3.6485 0.1369 2.8630 3.7105 0.00 T p Ionization Brems Pair prod Photonucl Total CSDA...

13

Table  

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

fluoride (CaF 2 ) ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.49670 3.180 166.0 0.06942 3.5263 0.0676 3.1683 4.0653 0.00 T p Ionization Brems Pair prod Photonucl Total CSDA...

14

Table  

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

fluoride (LiF) ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.46262 2.635 94.0 0.07593 3.7478 0.0171 2.7049 3.1667 0.00 T p Ionization Brems Pair prod Photonucl Total CSDA...

15

Table  

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

fluoride (BaF 2 ) ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.42207 4.893 375.9 0.15991 2.8867 -0.0099 3.3870 5.4116 0.00 T p Ionization Brems Pair prod Photonucl Total CSDA...

16

Table  

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

Methane (CH 4 ) ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.62334 6.672 10 -4 41.7 0.09253 3.6257 1.6263 3.9716 9.5243 0.00 T p Ionization Brems Pair prod Photonucl Total...

17

Table  

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

Methane based) ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.54993 1.064 10 -3 61.2 0.09946 3.4708 1.6442 4.1399 9.9500 0.00 T p Ionization Brems Pair prod Photonucl Total...

18

Table  

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

Ethanol (C 2 H 5 OH) ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.56437 0.789 62.9 0.09878 3.4834 0.2218 2.7052 3.3699 0.00 T p Ionization Brems Pair prod Photonucl Total...

19

Table  

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

Muons in Plutonium dioxide (PuO 2 ) ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.40583 11.460 746.5 0.20594 2.6522 -0.2311 3.5554 5.9719 0.00 T p Ionization Brems Pair prod...

20

Table  

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

Muons in Technetium Z A gmol gcm 3 I eV a k m s x 0 x 1 C 0 43 (Tc) 97.90722 (3) 11.500 428.0 0.16572 2.9738 0.0949 3.1253 4.7769 0.14 T p Ionization Brems Pair...

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


21

Table  

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

Muons in Benzene C 6 H 6 ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.53769 0.879 63.4 0.16519 3.2174 0.1710 2.5091 3.3269 0.00 T p Ionization Brems Pair prod Photonucl Total...

22

Table  

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

Muons in Butane (C 4 H 10 ) ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.59497 2.489 10 -3 48.3 0.10852 3.4884 1.3792 3.7528 8.5651 0.00 T p Ionization Brems Pair prod...

23

Table  

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

Muons in Thorium Z A gmol gcm 3 I eV a k m s x 0 x 1 C 0 90 (Th) 232.03806 (2) 11.720 847.0 0.08655 3.2610 0.4202 3.7681 6.2473 0.14 T p Ionization Brems Pair...

24

Table  

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

Muons in Liquid propane (C 3 H 8 ) ZA gcm 3 I eV a k m s x 0 x 1 C 0 0.58962 0.493 52.0 0.10329 3.5620 0.2564 2.6271 3.4162 0.00 T p Ionization Brems Pair prod...

25

Table  

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

Muons in Rhenium Z A gmol gcm 3 I eV a k m s x 0 x 1 C 0 75 (Re) 186.207 (1) 21.020 736.0 0.15184 2.8627 0.0559 3.4845 5.3445 0.08 T p Ionization Brems Pair prod...

26

Electron-pair excitations and the molecular Coulomb continuum  

DOE Green Energy (OSTI)

Electron-pair excitations in the molecular hydrogen continuum are described by quantizing rotations of the momentum plane of the electron pair about by the pair's relative momentum. A helium-like description of the molecular pi.Joto double ionization is thus extended to higher angular momenta of the electron pair. A simple three-state superposition is found to account surprisingly well for recent observations of noncoplanar electron-pair, molecular-axis angular distributions.

Colgan, James [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

27

Ionization chamber  

DOE Patents (OSTI)

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

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

1981-01-01T23:59:59.000Z

28

IONIZATION CHAMBER  

DOE Patents (OSTI)

This patent describes a novel ionization chamber which is well suited to measuring the radioactivity of the various portions of a wire as the wire is moved at a uniform speed, in order to produce the neutron flux traverse pattern of a reactor in which the wire was previously exposed to neutron radiation. The ionization chamber of the present invention is characterized by the construction wherein the wire is passed through a tubular, straight electrode and radiation shielding material is disposed along the wire except at an intermediate, narrow area where the second electrode of the chamber is located.

Redman, W.C.; Shonka, F.R.

1958-02-18T23:59:59.000Z

29

Matched-pair classification  

Science Conference Proceedings (OSTI)

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

Theiler, James P [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

30

Ionizing Radiation Dosimetry  

Science Conference Proceedings (OSTI)

Ionizing Radiation Dosimetry. ... OH. US Air Force Radiation Dosimetry Laboratory, Wright-Patterson - Base, OH [100548- 0] PA. ...

2013-09-06T23:59:59.000Z

31

NVLAP Ionizing Radiation Dosimetry LAP  

Science Conference Proceedings (OSTI)

Ionizing Radiation Dosimetry LAP. ... This site has been established for applicants to the accreditation program for ionizing radiation dosimetry. ...

2013-07-23T23:59:59.000Z

32

NIST Ionizing Radiation Division - 2001  

Science Conference Proceedings (OSTI)

... The Ionizing Radiation Division of the Physics Laboratory supports the ... meaningful, and compatible measurements of ionizing radiations (x rays ...

33

Ionization Energy Search  

Science Conference Proceedings (OSTI)

... SI calorie-based; Select the desired type(s) of ... search for species based on ionization energy values in ... Rules for data types (step 4) (Back to search). ...

2013-07-15T23:59:59.000Z

34

Soft ionization of thermally evaporated hypergolic ionic liquid aerosols  

Science Conference Proceedings (OSTI)

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

University of California; ERC, Incorporated, Edwards Air Force Base; Air Force Research Laboratory, Edwards Air Force Base; National Synchrotron Radiation Research Center (NSRRC); 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.

2011-07-19T23:59:59.000Z

35

NIST Ionizing Radiation Division - 1998  

Science Conference Proceedings (OSTI)

TECHNICAL ACTIVITIES 1998 - NISTIR 6268 IONIZING RADIATION DIVISION. The Neutron Interferometer. The neutron ...

36

NIST Ionizing Radiation Division - 2000  

Science Conference Proceedings (OSTI)

"Technical Activities 2000" - Table of Contents, Division home page. Ionizing Radiation Division. ...

37

Nuclear pairing: basic phenomena revisited  

E-Print Network (OSTI)

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

Bertsch, G F

2012-01-01T23:59:59.000Z

38

Context-sensitive dependency pairs  

Science Conference Proceedings (OSTI)

Termination is one of the most interesting problems when dealing with context-sensitive rewrite systems. Although there is a good number of techniques for proving termination of context-sensitive rewriting (CSR), the dependency pair approach, one of ... Keywords: dependency pairs, program analysis, term rewriting, termination

Beatriz Alarcón; Raúl Gutiérrez; Salvador Lucas

2006-12-01T23:59:59.000Z

39

Local pairs and small surfaces.  

SciTech Connect

More than 20 years after they were first discovered, high-temperature superconductors remain fundamentally baffling. In superconductors, conduction without electrical resistance arises through the pairing of electrons so as to overcome obstacles to current flow.

Julian, S. R.; Norman, M. R.; Materials Science Division; Univ. Toronto

2007-05-31T23:59:59.000Z

40

The Effects of Ionizing Irradiation  

Science Conference Proceedings (OSTI)

Page 1. The Effects of Ionizing Irradiation on Liquid, Dried, and Absorbed DNA Extracts ... Page 12. Study Shipped Land Carrier Irradiation ? ...

2012-02-29T23:59:59.000Z

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


41

Ionizing Radiation Division Quality Manual  

Science Conference Proceedings (OSTI)

... 08 47020C Low-energy Photon Brachytherapy Seeds, ... Calibrated for Surface Dose Rate 10 ... Sources Calibrated for Radiation Protection Ionization ...

2012-03-08T23:59:59.000Z

42

Numerical simulation of the pre-ionization processes during nanosecond-pulse discharge in nitrogen  

Science Conference Proceedings (OSTI)

The pre-ionization of nitrogen gas by high-voltage nanosecond pulse discharges is studied using one-dimensional particle-in-cell numerical simulations. The comparison between the various mechanisms of pre-ionization, i.e., by runaway electrons, x-rays, and ultraviolet radiation, is presented. It is shown that runaway electrons produce a much higher number of electron-ion pairs than those generated by x-rays, which accompany the process of runaway electron generation. Also, results of simulations showed that among photo-ionization mechanisms the most significant gas pre-ionization is caused by x-rays generated in the process of impact ionization of the K-shell of nitrogen atoms.

Levko, D.; Gurovich, V. Tz.; Krasik, Ya. E.

2012-01-01T23:59:59.000Z

43

Ionizing radiation detector  

DOE Patents (OSTI)

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

Thacker, L.H.

1989-06-08T23:59:59.000Z

44

Ionizing radiation detector  

DOE Patents (OSTI)

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

Thacker, Louis H. (Knoxville, TN)

1990-01-01T23:59:59.000Z

45

Ionization detection system for aerosols  

DOE Patents (OSTI)

This invention relates to an improved smoke-detection system of the ionization-chamber type. In the preferred embodiment, the system utilizes a conventional detector head comprising a measuring ionization chamber, a reference ionization chamber, and a normally non-conductive gas triode for discharging when a threshold concentration of airborne particulates is present in the measuring chamber. The improved system utilizes a measuring ionization chamber which is modified to minimize false alarms and reductions in sensitivity resulting from changes in ambient temperature. In the preferred form of the modification, an annular radiation shield is mounted about the usual radiation source provided to effect ionization in the measuring chamber. The shield is supported by a bimetallic strip which flexes in response to changes in ambient temperature, moving the shield relative to the source so as to vary the radiative area of the source in a manner offsetting temperature-induced variations in the sensitivity of the chamber.

Jacobs, Martin E. (Chillicothe, OH)

1977-01-01T23:59:59.000Z

46

High pressure xenon ionization detector  

DOE Patents (OSTI)

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.

Markey, John K. (New Haven, CT)

1989-01-01T23:59:59.000Z

47

High pressure xenon ionization detector  

DOE Patents (OSTI)

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.

Markey, J.K.

1989-11-14T23:59:59.000Z

48

Context-sensitive dependency pairs  

Science Conference Proceedings (OSTI)

Termination is one of the most interesting problems when dealing with context-sensitive rewrite systems. Although a good number of techniques for proving termination of context-sensitive rewriting (CSR) have been proposed so far, the adaptation to CSR ... Keywords: Dependency pairs, Program analysis, Term rewriting, Termination

Beatriz Alarcón; Raúl Gutiérrez; Salvador Lucas

2010-08-01T23:59:59.000Z

49

Cooper pair transfer in nuclei  

E-Print Network (OSTI)

The second order DWBA implementation of two-particle transfer direct reactions which includes simultaneous and successive transfer, properly corrected by non-orthogonality effects is tested with the help of controlled nuclear structure and reaction inputs against data spanning the whole mass table, and showed to constitute a quantitative probe of nuclear pairing correlations.

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

2013-04-09T23:59:59.000Z

50

Ionization of hydrogen and ionized helium by slow antiprotons  

E-Print Network (OSTI)

We study the ionization process involving antiproton and hydrogen in the energy range between 0.1 keV to 500 keV, using single center close coupling approximation. We construct the scattering wave function using B-spline bases. The results obtained for ionization of atomic hydrogen are compared with other existing theoretical calculations as well as with the available experimental data. The present results are found to be encouraging. We also employed this method to study the ionization of ionized helium in the energy range between 1 and 500 keV. On comparision, the present results are found to interpret well the cross section values calculated using other theories.

Sahoo, S; Walters, H R J

2004-01-01T23:59:59.000Z

51

Pulsed helium ionization detection system  

DOE Patents (OSTI)

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.

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

1985-04-09T23:59:59.000Z

52

Optical ionization detector  

DOE Patents (OSTI)

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

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

1994-01-01T23:59:59.000Z

53

Optical ionization detector  

DOE Patents (OSTI)

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

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

1994-03-29T23:59:59.000Z

54

Field ionization from carbon nanofibers  

E-Print Network (OSTI)

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

Adeoti, Bosun J

2008-01-01T23:59:59.000Z

55

Welding arc gap ionization device  

SciTech Connect

An alpha emitting isotope is positioned near the tip of a TIG welding electrode so that the alpha radiation can provide an ionized path between the electrode and the workpiece.

Schweikhardt, George M. (Richland, WA)

1976-01-01T23:59:59.000Z

56

Humidity effects in ionization chambers  

SciTech Connect

Capacitance variations due to humidity alterations have been suggested as the cause of ionization chamber current variations. The validity of the arguments is seriously questioned on several points. (auth)

Bengtsson, L.G.

1973-01-01T23:59:59.000Z

57

Ionizing Radiation Injury (South Carolina)  

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

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

58

Protection Against Ionizing Radiation in Extreme Radiation ...  

Science Conference Proceedings (OSTI)

Protection Against Ionizing Radiation in Extreme Radiation-resistant Microorganisms. ... Elucidated radiation protection by intracellular halides. ...

2013-05-01T23:59:59.000Z

59

Dynamical pairing states in cold gases  

E-Print Network (OSTI)

In this thesis, we study dynamical pairing of fermions caused by the time-dependent interaction. Fermionic pairing develops on time scales short compared to the quasiparticle relaxation time where existing approaches to ...

Barankov, Roman A

2006-01-01T23:59:59.000Z

60

Empirical evaluation of distributed pair programming  

Science Conference Proceedings (OSTI)

Pair programming, in which two individuals share a single computer to collaboratively develop software, has been shown to have many benefits in industry and in education. One drawback of pair programming is its collocation requirement, which limits its ... Keywords: Computer-supported cooperative work, Distributed pair programming, Empirical software engineering, Gesturing, Introductory programming

Brian Hanks

2008-07-01T23:59:59.000Z

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


61

Monopole-Antimonopole Pair Dyons  

Science Conference Proceedings (OSTI)

Monopole-antimonopole pair dyons are presented. The dyons possess opposite magnetic charge but carry the same electric charge. These stationary dyons possess finite energy. However they do not satisfy the first order Bogomol'nyi equations and are non-BPS solutions. They are axially symmetric and are characterized by a parameter, -1{<=}{eta}{<=}1 which determines the net electric charges of these dyons. These dyon solutions are solved numerically when the magnetic charge of the dipoles are n = {+-}1, {+-}2 for both vanishing and non-vanishing strength of the Higgs field potential. When {lambda} = 0, the dipole separation, total energy and net electric charge of the dyons increase exponentially fast to infinity when {eta} approaches {+-}1. However, when {lambda} = 1, all these three quantities approach finite critical values as {eta} approaches {+-}1.

Lim, Kok-Geng; Teh, Rosy; Wong, Khai-Ming [School of Physics, Universiti Sains Malaysia 11800 USM Penang (Malaysia)

2011-03-30T23:59:59.000Z

62

Effective pairing interactions with isospin density dependence  

Science Conference Proceedings (OSTI)

We perform Hartree-Fock-Bogoliubov (HFB) calculations for semi-magic calcium, nickel, tin, and lead isotopes and N=20,28,50, and 82 isotones using density-dependent pairing interactions recently derived from a microscopic nucleon-nucleon interaction. These interactions have an isovector component so that the pairing gaps in symmetric and neutron matter are reproduced. Our calculations well account for the experimental data for the neutron number dependence of binding energy, two-neutron separation energy, and odd-even mass staggering of these isotopes. This result suggests that by introducing the isovector term in the pairing interaction, one can construct a global effective pairing interaction that is applicable to nuclei in a wide range of the nuclear chart. It is also shown with the local density approximation that the pairing field deduced from the pairing gaps in infinite matter reproduces qualitatively well the pairing field for finite nuclei obtained with the HFB method.

Margueron, J. [Institut de Physique Nucleaire, IN2P3-CNRS and Universite Paris-Sud, F-91406 Orsay Cedex (France); Center for Mathematical Sciences, University of Aizu, Aizu-Wakamatsu, 965-8580 Fukushima (Japan); Sagawa, H. [Center for Mathematical Sciences, University of Aizu, Aizu-Wakamatsu, 965-8580 Fukushima (Japan); Hagino, K. [Department of Physics, Tohoku University, Sendai, 980-8578 (Japan)

2008-05-15T23:59:59.000Z

63

Factors affecting home range of mallard pairs  

SciTech Connect

Certain habitat and social factors were investigated for their effect on home range size of mallard (Anas platyhynchos) pairs breeding in a forested region of north-central Minnesota during the spring of 1971--72. Data from 31 radio-marked hens and drakes were used, but primary emphasis was placed on 8 pairs (5 with both members of the pair marked). Pairs were radio-tracked on river marsh areas, river channels, and large sand lakes to provide comparative data for evaluating home range size differences. Home ranges varied from an average of 53 ha for pairs using primarily river habitat to 871 ha for pairs using only large sand lakes. River and lake shorelines varied considerably in species and density of vegetation. Interaction between pairs as well as density of flocked males appeared to be influenced by these habitat differences with resultant effects on home range sizes.

Riechmann, J.H.

1976-06-01T23:59:59.000Z

64

Self-consistent chemical model of partially ionized plasmas  

Science Conference Proceedings (OSTI)

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

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

2011-01-15T23:59:59.000Z

65

Carbon nanotube-based field ionization vacuum  

E-Print Network (OSTI)

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 ...

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

2012-01-01T23:59:59.000Z

66

MUCOOL: Ionization Cooling R&D  

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

Laboratory MUCOOL Muon Ionization Cooling R&D Welcome to the muon ionization cooling experimental R&D page. The MuCool collaboration has been formed to pursue the development of a...

67

Microwave remote sensing of ionized air.  

SciTech Connect

We present observations of microwave scattering from ambient room air ionized with a negative ion generator. The frequency dependence of the radar cross section of ionized air was measured from 26.5 to 40 GHz (Ka-band) in a bistatic mode with an Agilent PNA-X series (model N5245A) vector network analyzer. A detailed calibration scheme is provided to minimize the effect of the stray background field and system frequency response on the target reflection. The feasibility of detecting the microwave reflection from ionized air portends many potential applications such as remote sensing of atmospheric ionization and remote detection of radioactive ionization of air.

Liao, S.; Gopalsami, N.; Heifetz, A.; Elmer, T.; Fiflis, P.; Koehl, E. R.; Chien, H. T.; Raptis, A. C. (Nuclear Engineering Division)

2011-07-01T23:59:59.000Z

68

Lesson 4 - Ionizing Radiation | Department of Energy  

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

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

69

Intelligent pairing assistant for air operation centers  

Science Conference Proceedings (OSTI)

Within an Air Operations Center (AOC), planners make crucial decisions to create the air plan for any given day. They are expected to complete the plan in part by pairing targeting or collection tasks with the available platforms. Any assistance these ... Keywords: air operations center, intelligent user interface, pairing, reinforcement learning

Jeremy Ludwig; Eric Geiselman

2012-02-01T23:59:59.000Z

70

Quantum Invariants of the Pairing Hamiltonian  

E-Print Network (OSTI)

Quantum invariants of the orbit dependent pairing problem are identified in the limit where the orbits become degenerate. These quantum invariants are simultaneously diagonalized with the help of the Bethe ansatz method and a symmetry in their spectra relating the eigenvalues corresponding to different number of pairs is discussed. These quantum invariants are analogous to the well known rational Gaudin magnet Hamiltonians which play the same role in the reduced pairing case (i.e., orbit independent pairing with non degenerate energy levels). It is pointed out that although the reduced pairing and the degenerate cases are opposite of each other, the Bethe ansatz diagonalization of the invariant operators in both cases are based on the same algebraic structure described by the rational Gaudin algebra.

Y. Pehlivan

2008-06-11T23:59:59.000Z

71

Sample Desorption/Ionization From Mesoporous Silica  

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

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

72

Ionization Energies, Electron Affinities and Electronegativies ... - TMS  

Science Conference Proceedings (OSTI)

Jun 28, 2007 ... Periodic table of the elements containing ionization energies, electron affinities, and electronegativities. CITATION: : R.E. Dickerson, H.B. Gray ...

73

Hall Magnetohydrodynamics of weakly-ionized plasma  

E-Print Network (OSTI)

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

B. P. Pandey; Mark Wardle

2006-08-01T23:59:59.000Z

74

NIST Ionizing Radiation Division 2000 - Future Directions  

Science Conference Proceedings (OSTI)

... will enable dose-reconstruction studies for populations exposed at the natural background levels of ionizing radiation. Calibrations of Low-Energy ...

75

Alloy solution hardening with solute pairs  

DOE Patents (OSTI)

Solution hardened alloys are formed by using at least two solutes which form associated solute pairs in the solvent metal lattice. Copper containing equal atomic percentages of aluminum and palladium is an example.

Mitchell, John W. (Charlottesville, VA)

1976-08-24T23:59:59.000Z

76

Distillation of vacuum entanglement to EPR pairs  

E-Print Network (OSTI)

It is shown that by means of local interactions between a quantized relativistic field and a pair of non-entangled atoms, entanglement can be extracted from the vacuum and delivered to the atoms. The resulting mixed state of the atoms can be further distilled to EPR pairs. Therefore, in principle, teleportation and other entanglement assisted quantum communication tasks can rely on the vacuum alone as a resource for entanglement.

Benni Reznik

2000-08-01T23:59:59.000Z

77

Ionization tube simmer current circuit  

DOE Patents (OSTI)

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

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

1994-01-01T23:59:59.000Z

78

Ionization tube simmer current circuit  

DOE Patents (OSTI)

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

Steinkraus, R.F. Jr.

1994-12-13T23:59:59.000Z

79

Pair-vibrational states in the presence of neutron-proton pairing  

E-Print Network (OSTI)

Pair vibrations are studied for a Hamiltonian with neutron-neutron, proton-proton and neutron-proton pairing. The spectrum is found to be rich in strongly correlated, low-lying excited states. Changing theratio of diagonal to off-diagonal pairing matrix elements is found to have a large impact on the excited-state spectrum. The variational configuration interaction (VCI) method, used to calculate the excitation spectrum, is found to be in very good agreement with exact solutions for systems with large degeneracies having equal T=0 and T=1 pairing strengths.

R. R. Chasman; P. Van Isacker

2010-01-18T23:59:59.000Z

80

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

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


81

NIST Ground Levels and Ionization Energies for the Neutral ...  

Science Conference Proceedings (OSTI)

The ionization energies in the table are based on a recent survey of ... cited compilation gives the reference(s) for the original ionization-energy data. ...

2013-09-16T23:59:59.000Z

82

Optimizing the Performance of Lithium Titanate Spinal Paired...  

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

Optimizing the Performance of Lithium Titanate Spinal Paired with Activated Carbon or Iron Phosphate Title Optimizing the Performance of Lithium Titanate Spinal Paired with...

83

Thermodynamics of pairing in mesoscopic systems  

E-Print Network (OSTI)

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

Tony Sumaryada; Alexander Volya

2007-06-12T23:59:59.000Z

84

Coulombic effect and renormalization in nuclear pairing  

Science Conference Proceedings (OSTI)

We investigate the effects of the Coulomb force on the nuclear pairing properties by performing the Gogny Hartree-Fock-Bogolyubov calculations for the N=20, 28, 50, 82, and 126 nuclei. The Coulomb force reduces the proton pair energy and the even-odd mass difference by about 25%, except for nuclei at and around the proton shell or subshell closure. We then propose a renormalization scheme via a reduction factor {gamma}{sub p} for the proton pairing channel. It is found that a single value {gamma}{sub p}=0.90 accounts well for the Coulombic effect for nuclei covering a wide range of the mass number and the neutron excess, including the nuclei around the shell or subshell closure.

Nakada, H.; Yamagami, M. [Department of Physics, Graduate School of Science, Chiba University, Yayoi-cho 1-33, Inage, Chiba 263-8522 (Japan); Department of Computer Science and Engineering, University of Aizu, Aizu-Wakamatsu, Fukushima 965-8580 (Japan)

2011-03-15T23:59:59.000Z

85

Holographic EPR Pairs, Wormholes and Radiation  

E-Print Network (OSTI)

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

Chernicoff, Mariano; Pedraza, Juan F

2013-01-01T23:59:59.000Z

86

Charged-Particle Impact Ionization of Atoms  

Science Conference Proceedings (OSTI)

We have developed a hybrid method to treat charged-particle impact ionization of complex atoms and ions. The essential idea is to describe the interaction between a fast projectile and the target perturbatively, up to second order, while the initial bound state and the ejected-electron--residual-ion interaction can be handled via a convergent R-matrix with pseudo-states (close-coupling) expansion. Example results for ionization of the heavy noble gases (Ne-Xe) by positron and electron impact are presented. The general scheme for a distorted-wave treatment of ionization by heavy-particle impact is described.

Bartschat, Klaus; Guan Xiaoxu [Department of Physics and Astronomy, Drake University, Des Moines, IA 50311 (United States)

2008-08-08T23:59:59.000Z

87

Representability of Pairing Relation Algebras Representability of Pairing Relation Algebras Depends on our Ontology  

Science Conference Proceedings (OSTI)

We consider classes of relation algebras expanded with new operations based on the formation of ordered pairs. Examples for such algebras are pairing (or projection) algebras of algebraic logic and fork algebras of computer science. It is proved by Sain ... Keywords: non-well-founded set theories, projection elements, relation algebra

Agnes Kurucz; István Németi

2000-12-01T23:59:59.000Z

88

A numerical scheme for ionizing shock waves  

Science Conference Proceedings (OSTI)

A two-dimensional (2D) visual computer code to solve the steady state (SS) or transient shock problems including partially ionizing plasma is presented. Since the flows considered are hypersonic and the resulting temperatures are high, the plasma is ...

Necdet Aslan; Michael Mond

2005-12-01T23:59:59.000Z

89

Theory of electron transfer and ionization  

DOE Green Energy (OSTI)

The main effort reported is directed toward charge transfer and ionization in high energy atomic collisions. The research may be divided into classical trajectory calculations, quantum - mechanical collision theory, and phenomenological treatments of quantal interference effects in heavy ion collisions.

Becker, R.L.

1979-01-01T23:59:59.000Z

90

Arithmetic Operators for Pairing-Based Cryptography  

Science Conference Proceedings (OSTI)

Since their introduction in constructive cryptographic applications, pairings over (hyper)elliptic curves are at the heart of an ever increasing number of protocols. Software implementations being rather slow, the study of hardware architectures became ... Keywords: ?Tpairing, FPGA, elliptic curve, finite field arithmetic, hardware accelerator

Jean-Luc Beuchat; Nicolas Brisebarre; Jérémie Detrey; Eiji Okamoto

2007-09-01T23:59:59.000Z

91

The free energy of vacancy pairs  

Science Conference Proceedings (OSTI)

The configurational free energy change ?A 2/k T associated with the introduction of pairs of vacancy defects into a two?dimensional triangular lattice with nearest neighbor interactions is calculated by lattice dynamics in the classical high temperature limit. It is found that second and third nearest neighbor vacancies yield the greatest decrease in the free energy.

Robert Cook; Alan Shuldiner

1978-01-01T23:59:59.000Z

92

Gas amplified ionization detector for gas chromatography  

DOE Patents (OSTI)

A gas-amplified ionization detector for gas chromatography which possesses increased sensitivity and a very fast response time is described. Solutes eluding from a gas chromatographic column are ionized by uv photoionization of matter eluting therefrom. The detector is capable of generating easily measured voltage signals by gas amplification/multiplication of electron products resulting from the uv photoionization of at least a portion of each solute passing through the detector. 4 figs.

Huston, G.C.

1989-11-27T23:59:59.000Z

93

AN IONIZATION CHAMBER LAUNDRY MONITOR  

SciTech Connect

The determination of the amount of contamination remaining on a garment after it has been washed is an important part of hot laundry operations. In the past garments were monitored by measuring the contamination concentrated in the crotch with a GM tube probe. This type of spot check does not detect any isolated hot spots on other pants of the garment. To monitor the entire garment with a GM tube instrument is excessively time consuming for a large number of garments. To overcome these difficulties a sensitive, large-volume ionization chamber was constructed. It is rectangular in shape, 5 ft high by 2 1/2 ft wide by 4 in. deep. The center electrode is of a grid type and is mounted halfway between the front window and the back of the chamber. In a 0.5-mr/hr field, 180 v is sufficient to saturate toe chamber. In order to insure beta sensitivity, the front window has an equivalent thickness of approximately 7 mg/cm/sup 2/. The measuring device is a line-operated electrometer circuit equipped with an alarm that may be set at the rejection limit for the type of garment being monitored. A fullscale deflection on the most sensitive range is given by 2 to 3 mu C of liquid mixed fission products deposited on a garment. Since the chamber monitors the entire garment, the results are independent of the location of the contarnination. In practice, garments may be monitored at the rate of 7 per min, while only 3 per min may be completely checked with a GM tube probs. Field tests indicate that this instrument is stable and trouble free. Background causes a meter deflection of about 20 divisions, which is low enough to give reliable accuracy for monitoring garments. (auth)

Chester, J.D.; Handloser, J.S.

1958-06-01T23:59:59.000Z

94

Ionization of Rydberg atoms by blackbody radiation  

E-Print Network (OSTI)

We have studied an ionization of alkali-metal Rydberg atoms by blackbody radiation (BBR). The results of the theoretical calculations of ionization rates of Li, Na, K, Rb and Cs Rydberg atoms are presented. Calculations have been performed for nS, nP and nD states which are commonly used in a variety of experiments, at principal quantum numbers n=8-65 and at the three ambient temperatures of 77, 300 and 600 K. A peculiarity of our calculations is that we take into account the contributions of BBR-induced redistribution of population between Rydberg states prior to photoionization and field ionization by extraction electric field pulses. The obtained results show that these phenomena affect both the magnitude of measured ionization rates and shapes of their dependences on n. A Cooper minimum for BBR-induced transitions between bound Rydberg states of Li has been found. The calculated ionization rates are compared with our earlier measurements of BBR-induced ionization rates of Na nS and nD Rydberg states with ...

Beterov, I I; Ryabtsev, I I; Entin, V M; Ekers, A; Bezuglov, N N

2008-01-01T23:59:59.000Z

95

Ionization Yield from Nuclear Recoils in Liquid-Xenon Dark Matter Detection  

E-Print Network (OSTI)

The ionization yield in the two-phase liquid xenon dark-matter detector has been studied in keV nuclear-recoil energy region. The newly-obtained nuclear quenching as well as the recently-measured average energy required to produce an electron-ion pair are used to calculate the total electric charges produced. To estimate the fraction of the electron charges collected, the Thomas-Imel model is generalized to describing the field dependence for nuclear recoils in liquid xenon. With free parameters fitted to experiment measured 56.5 keV nuclear recoils, the energy dependence of ionization yield for nuclear recoils is predicted, which increases with the decreasing of the recoiling energy and reaches the maximum value at 2~3 keV. This prediction agrees well with existing data and may help to lower the energy detection threshold for nuclear recoils to ~1 keV.

Mu, Wei

2013-01-01T23:59:59.000Z

96

The first known type (7,1) amicable pair  

Science Conference Proceedings (OSTI)

Amicable pairs of type (i, 1) have been the object of special search partly because they breed other amicable pairs. Examples exist for i = 2, 3, 4, 5, and 6. In this paper we exhibit the first known type (7, 1) pair. Keywords: amicable pairs

Mariano Garcia

2003-04-01T23:59:59.000Z

97

Ionization in Atmospheres of Brown Dwarfs and Extrasolar Planets V: Alfv\\'{e}n Ionization  

E-Print Network (OSTI)

Observations of continuous radio and sporadic X-ray emission from low-mass objects suggest they harbour localized plasmas in their atmospheric environments. For low-mass objects, the degree of thermal ionization is insufficient to qualify the ionized component as a plasma, posing the question: what ionization processes can efficiently produce the required plasma that is the source of the radiation? We propose Alfv\\'{e}n ionization as a mechanism for producing localized pockets of ionized gas in the atmosphere, having sufficient degrees of ionization ($\\geq10^{-7}$) that they constitute plasmas. We outline the criteria required for Alfv\\'{e}n ionization and demonstrate it's applicability in the atmospheres of low-mass objects such as giant gas planets, brown dwarfs and M-dwarfs for both solar and sub-solar metallicities. We find that Alfv\\'{e}n ionization is most efficient at mid to low atmospheric pressures where a seed plasma is easier to magnetize and the pressure gradients needed to drive the required neut...

Stark, Craig R; Diver, Declan A; Rimmer, Paul B

2013-01-01T23:59:59.000Z

98

Molecular Dynamics Model of Ultraviolet Matrix-Assisted Laser Desorption/Ionization Including Ionization Processes  

E-Print Network (OSTI)

Molecular Dynamics Model of Ultraviolet Matrix-Assisted Laser Desorption/Ionization Including A molecular dynamics model of UV-MALDI including ionization processes is presented. In addition/desorption of molecular systems, it includes radiative and nonradiative decay, exciton hopping, two pooling processes

Zhigilei, Leonid V.

99

Pseudogap Pairing in Ultracold Fermi Atoms  

Science Conference Proceedings (OSTI)

The Bose-Einstein condensate to Bardeen-Cooper-Schrieffer crossover in ultracold Fermi gases creates an ideal environment to enrich our knowledge of many-body systems. It is relevant to a wide range of fields from condensed matter to astrophysics. The nature of pairing in strongly interacting Fermi gases can be readily studied. This aids our understanding of related problems in high-T{sub c} superconductors, whose mechanism is still under debate due to the large interaction parameter. Here, we calculate the dynamical properties of a normal, trapped strongly correlated Fermi gas, by developing a quantum cluster expansion. Our calculations for the single-particle spectral function agree with recent rf spectroscopy measurements, and clearly demonstrate pseudogap pairing in the strongly interacting regime.

Hu Hui; Liu Xiaji; Drummond, Peter D. [ARC Centre of Excellence for Quantum-Atom Optics and Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122 (Australia); Dong Hui [ARC Centre of Excellence for Quantum-Atom Optics and Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122 (Australia); Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100080 (China)

2010-06-18T23:59:59.000Z

100

PAIR (Planning and Analysis of Inspection Resources)  

SciTech Connect

The safeguards inspection effort of the International Atomic Energy Agency consists of the efforts for the Physical Inventory Verifications to close the annual material balance, Interim Inventory Verifications, conducted mainly to satisfy the Timeliness Criteria, Flow Verifications to verify the transfer of material, and Containment and Surveillance activities, which help preserve continuity of knowledge concerning the material. Estimating the requiring overall future inspection effort under a variety of conditions is an important part of Agency planning. As exemplified by the sample results provides a straightforward means to analyze `What if` situations in safeguards implementation. It thereby permits managers and analysts to study future scenarios and their effect on human resources. It is planned to introduce into PAIR a direct capability for studying costs associated with these hypothetical changes in safeguards implementation. In this way PAIR could more easily assist the Safeguards Department in its current program of investigating new safeguards approaches.

Teichmann, T.; Santaniello, A. [Brookhaven National Lab., Upton, NY (United States); Fishbone, L.G. [International Atomic Energy Agency, Vienna (Austria)

1994-03-01T23:59:59.000Z

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


101

A search for resonant Z pair production  

SciTech Connect

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

Boveia, Antonio; /UC, Santa Barbara

2008-12-01T23:59:59.000Z

102

Heat capacity and pairing transition in nuclei  

E-Print Network (OSTI)

A simple model based on the canonical-ensemble theory is outlined for hot nuclei. The properties of the model are discussed with respect to the Fermi gas model and the breaking of Cooper pairs. The model describes well the experimental level density of deformed nuclei in various mass regions. The origin of the so-called S-shape of the heat capacity curve Cv(T) is discussed.

M. Guttormsen; M. Hjorth-Jensen; E. Melby; J. Rekstad; A. Schiller; S. Siem

2001-04-30T23:59:59.000Z

103

Simple, pulsed, polarisation entangled photon pair source  

E-Print Network (OSTI)

We report the realisation of a fibred polarisation entangled photon-pair source at 1560 nm based on a type-II non linear interaction and working in the picosecond regime. By taking advantage of a set of filters, we deterministically separate the photons and project them into wavelength separable states. A standard entanglement measurement with a net interference visibility close to 1, proves the relevance of our approach as an enabling technology for entanglement-based quantum communication.

N. Bruno; E. Zambrini Cruzeiro; A. Martin; R. T. Thew

2013-11-26T23:59:59.000Z

104

MUCOOL: Ionization Cooling R&D  

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

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

105

Ionization-chamber smoke detector system  

DOE Patents (OSTI)

This invention relates to an improved smoke-detection system of the ionization-chamber type. In the preferred embodiment, the system utilizes a conventional detector head comprising a measuring ionization chamber, a reference ionization chamber, and a normally non-conductive gas triode for discharging when a threshold concentration of airborne particulates is present in the measuring chamber. The improved system is designed to reduce false alarms caused by fluctuations in ambient temperature. Means are provided for periodically firing the gas discharge triode and each time recording the triggering voltage required. A computer compares each triggering voltage with its predecessor. The computer is programmed to energize an alarm if the difference between the two compared voltages is a relatively large value indicative of particulates in the measuring chamber and to disregard smaller differences typically resulting from changes in ambient temperature.

Roe, Robert F. (Jackson, OH)

1976-10-19T23:59:59.000Z

106

Stable optical vortex solitons in pair plasmas  

Science Conference Proceedings (OSTI)

It is shown that the pair plasmas with small temperature asymmetry can support existence of localized as well as delocalized optical vortex solitons. Coexistence of such solitons is possible due to peculiar form of saturating nonlinearity which has a focusing-defocusing nature--for weak amplitudes being focusing becoming defocusing for higher amplitudes. It is shown that delocalized vortex soliton is stable in entire region of its existence while single- and multicharged localized vortex solitons are unstable for low amplitudes and become stable for relativistic amplitudes.

Berezhiani, V. I.; Shatashvili, N. L. [Plasma Physics Department, Andronikashvili Institute of Physics, Tbilisi 0177 (Georgia); Department of Physics, Faculty of Exact and Natural Sciences, Javakhishvili Tbilisi State University, Tbilisi 0128 (Georgia); Mahajan, S. M. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)

2010-05-15T23:59:59.000Z

107

Pair Production in Rotating Electric Fields  

E-Print Network (OSTI)

We explore Schwinger pair production in rotating time-dependent electric fields using the real-time DHW formalism. We determine the time evolution of the Wigner function as well as asymptotic particle distributions neglecting back-reactions on the electric field. Whereas qualitative features can be understood in terms of effective Keldysh parameters, the field rotation leaves characteristic imprints in the momentum distribution that can be interpreted in terms of interference and multiphoton effects. These phenomena may seed characteristic features of QED cascades created in the antinodes of a high-intensity standing wave laser field.

Blinne, Alexander

2013-01-01T23:59:59.000Z

108

Pair Production in Rotating Electric Fields  

E-Print Network (OSTI)

We explore Schwinger pair production in rotating time-dependent electric fields using the real-time DHW formalism. We determine the time evolution of the Wigner function as well as asymptotic particle distributions neglecting back-reactions on the electric field. Whereas qualitative features can be understood in terms of effective Keldysh parameters, the field rotation leaves characteristic imprints in the momentum distribution that can be interpreted in terms of interference and multiphoton effects. These phenomena may seed characteristic features of QED cascades created in the antinodes of a high-intensity standing wave laser field.

Alexander Blinne; Holger Gies

2013-11-07T23:59:59.000Z

109

THE HEALTH EFFECTS IN WOMEN EXPOSED TO LOW-LEVELS OF IONIZING RADIATION  

E-Print Network (OSTI)

and Effects of Ionizing Radiation. New York, United Nations,Effects of Ionizing Radiation (BEIR III). The EffectsLevels of Ionizing Radiation. Washington, D.C. , National

Fabrikant, J.I.

2010-01-01T23:59:59.000Z

110

Boson-Fermion pairing in a Boson-Fermion environment  

E-Print Network (OSTI)

Propagation of a Boson-Fermion (B-F) pair in a B-F environment is considered. The possibility of formation of stable strongly correlated B-F pairs, embedded in the continuum, is pointed out. The new Fermi gas of correlated B-F pairs shows a strongly modified Fermi surface. The interaction between like particles is neglected in this exploratory study. Various physical situations where our new pairing mechanism could be of importance are invoked.

A. Storozhenko; P. Schuck; T. Suzuki; H. Yabu; J. Dukelsky

2005-04-10T23:59:59.000Z

111

Supermassive Black Holes and the Warm Ionized  

E-Print Network (OSTI)

Supermassive Black Holes and the Warm Ionized Gas in Early-type Galaxies Renbin Yan University stars actively. (late-type galaxies) #12;Prevalence of Supermassive Black Holes in Massive Galaxies MBH merging Right after coalescing Post-merger Star Formation Rate Black Hole Accretion Rate #12;Maintenance

Wang, Ming-Jye

112

Route to direct multiphoton multiple ionization  

Science Conference Proceedings (OSTI)

We address the concept of direct multiphoton multiple ionization in atoms exposed to intense, short-wavelength radiation and explore the conditions under which such processes dominate over the sequential. Their contribution is shown to be quite robust, even under intensity fluctuations and interaction volume integration, and reasonable agreement with experimental data is also found.

Lambropoulos, P. [Institute of Electronic Structure and Laser, FORTH, P.O. Box 1527, GR-71110 Heraklion (Greece); Department of Physics, University of Crete, P.O. Box 2208, GR-71003 Heraklion, Crete (Greece); Kavli Institute for Theoretical Physics, Santa Barbara, California 93106 (United States); Nikolopoulos, G. M. [Institute of Electronic Structure and Laser, FORTH, P.O. Box 1527, GR-71110 Heraklion (Greece); Kavli Institute for Theoretical Physics, Santa Barbara, California 93106 (United States); Papamihail, K. G. [Department of Physics, University of Crete, P.O. Box 2208, GR-71003 Heraklion, Crete (Greece)

2011-02-15T23:59:59.000Z

113

Efficient pairing computation on Elliptic curves in Hessian form  

Science Conference Proceedings (OSTI)

Pairings in elliptic curve cryptography are functions which map a pair of elliptic curve points to a non-zero element of a finite field. In recent years, many useful cryptographic protocols based on pairings have been proposed. The fast implementations ... Keywords: Elliptic curve, Hessian form, tate paring

Haihua Gu; Dawu Gu; WenLu Xie

2010-12-01T23:59:59.000Z

114

Brief paper: Branch and bound method for multiobjective pairing selection  

Science Conference Proceedings (OSTI)

Most of the available methods for selection of input-output pairings for decentralized control require evaluation of all alternatives to find the optimal pairings. As the number of alternatives grows rapidly with process dimensions, pairing selection ... Keywords: Computer-aided control system design, Decentralized control, Global optimization, Large-scale systems, Multiobjective optimizations, Relative gain array, Structured singular value

Vinay Kariwala; Yi Cao

2010-05-01T23:59:59.000Z

115

Electron Ionization Library Component of the NIST/EPA/NIH ...  

Science Conference Proceedings (OSTI)

Electron Ionization Library Component of the NIST/EPA/NIH Mass Spectral Library and NIST GC Retention Index Database. Summary: ...

2013-07-10T23:59:59.000Z

116

Probe measurements of the ionization of air behind strong shocks  

SciTech Connect

Detailed measurements of the ionization of air behind strong shocks over a broad range of shocks velocities are reported. (AIP)

Gorelov, V.A.; Kil' dyushova, L.A.

1981-11-01T23:59:59.000Z

117

Cooper pairing near charged black holes  

E-Print Network (OSTI)

We show that a quartic contact interaction between charged fermions can lead to Cooper pairing and a superconducting instability in the background of a charged asymptotically Anti-de Sitter black hole. For a massless fermion we obtain the zero mode analytically and compute the dependence of the critical temperature T_c on the charge of the fermion. The instability we find occurs at charges above a critical value, where the fermion dispersion relation near the Fermi surface is linear. The critical temperature goes to zero as the marginal Fermi liquid is approached, together with the density of states at the Fermi surface. Besides the charge, the critical temperature is controlled by a four point function of a fermionic operator in the dual strongly coupled field theory.

Hartman, Thomas

2010-01-01T23:59:59.000Z

118

Cooper pairing near charged black holes  

E-Print Network (OSTI)

We show that a quartic contact interaction between charged fermions can lead to Cooper pairing and a superconducting instability in the background of a charged asymptotically Anti-de Sitter black hole. For a massless fermion we obtain the zero mode analytically and compute the dependence of the critical temperature T_c on the charge of the fermion. The instability we find occurs at charges above a critical value, where the fermion dispersion relation near the Fermi surface is linear. The critical temperature goes to zero as the marginal Fermi liquid is approached, together with the density of states at the Fermi surface. Besides the charge, the critical temperature is controlled by a four point function of a fermionic operator in the dual strongly coupled field theory.

Thomas Hartman; Sean A. Hartnoll

2010-03-09T23:59:59.000Z

119

Method for sequencing DNA base pairs  

DOE Patents (OSTI)

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.

Sessler, A.M.; Dawson, J.

1993-12-14T23:59:59.000Z

120

Improved method for sequencing DNA base pairs  

DOE Patents (OSTI)

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. 1 ref.

Sessler, A.M.; Dawson, J.

1990-12-31T23:59:59.000Z

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


121

Improved method for sequencing DNA base pairs  

DOE Patents (OSTI)

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. 1 ref.

Sessler, A.M.; Dawson, J.

1990-01-01T23:59:59.000Z

122

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

E-Print Network (OSTI)

Collaboratory for Advanced Computing and Simulations, Department of Physics & Astronomy, Department of Chemical at the Collaboratory for Advanced Computing and Simulations. 1K. L. McNesby, A. W. Miziolek, T. Nguyen, F. C. Delucia 78, 024304 (2008). 74J. Rylance and D. Stubley, Thermochim. Acta 13, 253 (1975). 75J. F. Baytos

Utah, University of

123

Composite scintillators for detection of ionizing radiation  

DOE Patents (OSTI)

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

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

2010-12-28T23:59:59.000Z

124

Alloy nanoparticle synthesis using ionizing radiation  

DOE Patents (OSTI)

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

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

2011-08-16T23:59:59.000Z

125

Nucleic Acid Standards | Base Pair Geometry  

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

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

126

A Bell pair in a generic random matrix environment  

E-Print Network (OSTI)

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

Carlos Pineda; Thomas H. Seligman

2006-05-18T23:59:59.000Z

127

Correlated photon pairs generated from a warm atomic ensemble  

E-Print Network (OSTI)

We present measurements of the cross-correlation function of photon pairs at 780 nm and 1367 nm, generated in a hot rubidium vapor cell. The temporal character of the biphoton is determined by the dispersive properties of the medium where the pair generation takes place. We show that short correlation times occur for optically thick samples, which can be understood in terms of off-resonant pair generation. By modifying the linear response of the sample, we produce near-resonant photon pairs, which could in principle be used for entanglement distribution.

Willis, R T; Orozco, L A; Rolston, S L

2010-01-01T23:59:59.000Z

128

Correlated photon pairs generated from a warm atomic ensemble  

E-Print Network (OSTI)

We present measurements of the cross-correlation function of photon pairs at 780 nm and 1367 nm, generated in a hot rubidium vapor cell. The temporal character of the biphoton is determined by the dispersive properties of the medium where the pair generation takes place. We show that short correlation times occur for optically thick samples, which can be understood in terms of off-resonant pair generation. By modifying the linear response of the sample, we produce near-resonant photon pairs, which could in principle be used for entanglement distribution.

R. T. Willis; F. E. Becerra; L. A. Orozco; S. L. Rolston

2010-11-11T23:59:59.000Z

129

Waveshifters and Scintillators for Ionizing Radiation Detection  

Science Conference Proceedings (OSTI)

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.

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

2007-12-11T23:59:59.000Z

130

Pairing: from atomic nuclei to neutron-star crusts  

E-Print Network (OSTI)

Nuclear pairing is studied both in atomic nuclei and in neutron-star crusts in the unified framework of the energy-density functional theory using generalized Skyrme functionals complemented with a local pairing functional obtained from many-body calculations in homogeneous nuclear matter using realistic forces.

Chamel, N; Goriely, S

2013-01-01T23:59:59.000Z

131

High speed flexible pairing cryptoprocessor on FPGA platform  

Science Conference Proceedings (OSTI)

This paper presents a Pairing Crypto Processor (PCP) over Barreto-Naehrig curves (BN curves). The proposed architecture is specifically designed for field programmable gate array (FPGA) platforms. The design of PCP utilizes the efficient implementation ... Keywords: Barreto-Naehrig curves, Fpk-arithmetic, FPGA, ellipticcurve cryptography (ECC), pairing-based cryptography

Santosh Ghosh; Debdeep Mukhopadhyay; Dipanwita Roychowdhury

2010-12-01T23:59:59.000Z

132

Exceptional Lie Algebras, SU(3) and Jordan Pairs  

E-Print Network (OSTI)

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

Piero Truini

2011-12-06T23:59:59.000Z

133

Hindi paired word recognition using probabilistic neural network  

Science Conference Proceedings (OSTI)

Automatic speech recognition has been a subject of active research interest since last few decades. In the present paper, spoken Hindi (Indian national language) Paired Word Recognition (HPWR) has been examined with the help of intelligent ... Keywords: HPWR, Hindi, PNN, automatic speech recognition, broad acoustic classes, classification, hybrid computing, paired word recognition, pattern recognition, probabilistic neural networks, wavelet transforms

Dinesh Kumar Rajoriya; R. S. Anand; R. P. Maheshwari

2010-08-01T23:59:59.000Z

134

LCPHSM2004006 Study of Higgs Boson Pair Production at  

E-Print Network (OSTI)

LC­PHSM­2004­006 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

135

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

136

Dielectric liquid ionization chambers for detecting fast neutrons  

E-Print Network (OSTI)

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

Boyd, Erin M

2008-01-01T23:59:59.000Z

137

Impact of Low-Dose Ionizing Irradiation on Histone Modification...  

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

Impact of Low-Dose Ionizing Irradiation on Histone Modification and Chromatin Organization Hunter W. Richards Lawrence Berkeley National Laboratory Abstract Goal Our goal is to...

138

Impact of Low-Dose Ionizing Irradiation on Histone Modification...  

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

Low-Dose Ionizing Irradiation on Histone Modification and Chromatin Organization Hunter W. Richards, Steven D. Ayers, Shutao Cai, Yoshinori Kohwi, Gary Karpen, Sylvain Costes and...

139

Intense laser field ionization of atom and molecular ion.  

E-Print Network (OSTI)

??In order to understand how does the intense laser interact with matter we first of all study the ionization process. In this highly nonlinear region… (more)

Long, Zi Jian

2008-01-01T23:59:59.000Z

140

Ionized channel generation of an intense-relativistic electron beam  

DOE Patents (OSTI)

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

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

1988-01-01T23:59:59.000Z

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


141

NIST Ionizing Radiat. Div. - 2004: Strategic Focus 1  

Science Conference Proceedings (OSTI)

... and to determine exposure or dose-rate values ... to maximize the energy absorption of the ionizing radiation. ... the calibration of an 55 Fe low-energy x ...

142

Template:LabelValuePair | Open Energy Information  

Open Energy Info (EERE)

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

143

Inflation of the screening length induced by Bjerrum pairs  

E-Print Network (OSTI)

Within a modified Poisson-Boltzmann theory we study the effect of Bjerrum pairs on the typical length scale $1/\\bar{\\kappa}$ over which electric fields are screened in electrolyte solutions, taking into account a simple association-dissociation equilibrium between free ions and Bjerrum pairs. At low densities of Bjerrum pairs, this length scale is well approximated by the Debye length $1/\\kappa\\propto 1/\\sqrt{\\rho_\\mathrm{s}}$, with $\\rho_\\mathrm{s}$ the free ion density. At high densities of Bjerrum pairs, however, we find $1/\\bar{\\kappa}\\propto \\sqrt{\\rho_\\mathrm{s}}$ which is significantly larger than $1/\\kappa$ due to the enhanced effective permittivity of the electrolyte, caused by the polarization of Bjerrum pairs. We argue that this mechanism may explain the recently observed anomalously large colloid-free zones between an oil-dispersed colloidal crystal and a colloidal monolayer at the oil-water interface.

Jos Zwanikken; René van Roij

2009-05-12T23:59:59.000Z

144

Amplifier Design for Proportional Ionization Chambers  

SciTech Connect

This paper presents the requirements of a nuclear amplifier of short resolving time, designed to accept pulses of widely varying amplitudes. Data are given which show that a proportional ionization chamber loaded with a 1,000-ohm resistor develops pulses of 0.5 microsecond duration and several volts amplitude. Results indicate that seven basic requirements are imposed on the amplifier when counting soft beta and gamma radiation in the presence of alpha particles, without absorbers. It should, (1) have a fast recovery time, (2) have a relatively good low frequency response, (3) accept pulses of widely varying heights without developing spurious pulsed, (4) have a limiting output stage, (5) preserve the inherently short rise time of the chamber, (6) minimize pulse integration, and (7) have sufficient gain to detect the weak pulses well below the chamber voltage at which continuous discharge takes place. The results obtained with an amplifier which meets these requirements is described. A formula is derived which indicates that redesign of the proportional ionization chamber might eliminate the need for an amplifier. This may be possible if the radioactive particles are collimated parallel to the collecting electrode.

Baker, W. H.

1950-08-24T23:59:59.000Z

145

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

Science Conference Proceedings (OSTI)

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

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

2010-08-15T23:59:59.000Z

146

QED peripheral mechanism of pair production at colliders  

Science Conference Proceedings (OSTI)

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

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

2008-10-01T23:59:59.000Z

147

General heart construction for twin torsion pairs on triangulated categories  

E-Print Network (OSTI)

In our previous article, we constructed an abelian category from any torsion pair on a triangulated category. This generalizes the heart of a $t$-structure and the ideal quotient by a cluster tilting subcategory. Recently, generalizing the quotient by a cluster tilting subcategory, Buan and Marsh showed that an integral preabelian category can be constructed as a quotient, from a rigid object in a triangulated category with some conditions. In this article, by considering a pair of torsion pairs, we make a simultaneous genralization of these two constructions.

Nakaoka, Hiroyuki

2011-01-01T23:59:59.000Z

148

Phase space evolution of pairs created in strong electric fields  

E-Print Network (OSTI)

We study the process of energy conversion from overcritical electric field into electron-positron-photon plasma. We solve numerically Vlasov-Boltzmann equations for pairs and photons assuming the system to be homogeneous and anisotropic. All the 2-particle QED interactions between pairs and photons are described by collision terms. We evidence several epochs of this energy conversion, each of them associated to a specific physical process. Firstly pair creation occurs, secondly back reaction results in plasma oscillations. Thirdly photons are produced by electron-positron annihilation. Finally particle interactions lead to completely equilibrated thermal electron-positron-photon plasma.

Benedetti, Alberto; Vereshchagin, Gregory; 10.1016/j.physleta.2012.11.026

2013-01-01T23:59:59.000Z

149

Photon-pair generation in random nonlinear layered structures  

E-Print Network (OSTI)

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.

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

2009-08-25T23:59:59.000Z

150

The Nature of Ionized Gas in Giant Elliptical Galaxies  

E-Print Network (OSTI)

I review the current understanding of the origin and nature of ``warm'' ionized gas in giant elliptical galaxies in the light of results of recent imaging and spectroscopic surveys. CCD imaging surveys have revealed that emission-line disks or filaments are (as a rule) associated with dust absorption, even in the X-ray brightest systems. This strongly suggests that the origin of this ionized gas is generally not through ``cooling flows''; galaxy interactions are favored instead. Using data from a new spectrophotometric survey of ``normal'' elliptical galaxies covering the whole optical range, the extended ionized gas in giant ellipticals is found to be --without exception-- of the LINER class, and most probably NOT powered by star formation activity. I discuss two independent pieces of evidence which suggest that the extended gas in giant ellipticals is ionized by means of a distributed source of ionization: (i) A significant correlation exists between the H-alpha+[NII]luminosity and the optical luminosity within the region occupied by the ionized gas, and (ii) the ionization parameter of the gas does not change significantly with galactocentric radius. Two potential sources of ionization are evaluated: Photoionization by old hot stars (of post-AGB and/or AGB-Manque' type) and mechanical energy flux from electron conduction in hot, X-ray-emitting gas.

Paul Goudfrooij

1998-09-04T23:59:59.000Z

151

Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation  

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

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

152

Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation  

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

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

153

Electron-positron pairs production in a macroscopic charged core  

E-Print Network (OSTI)

Classical and semi-classical energy states of relativistic electrons bounded by a massive and charged core with the charge-mass-radio Q/M and macroscopic radius R_c are discussed. We show that the energies of semi-classical (bound) states can be much smaller than the negative electron mass-energy (-mc^2), and energy-level crossing to negative energy continuum occurs. Electron-positron pair production takes place by quantum tunneling, if these bound states are not occupied. Electrons fill into these bound states and positrons go to infinity. We explicitly calculate the rate of pair-production, and compare it with the rates of electron-positron production by the Sauter-Euler-Heisenberg-Schwinger in a constant electric field. In addition, the pair-production rate for the electro-gravitational balance ratio Q/M = 10^{-19} is much larger than the pair-production rate due to the Hawking processes.

Ruffini, Remo

2011-01-01T23:59:59.000Z

154

Electron-positron pairs production in a macroscopic charged core  

E-Print Network (OSTI)

Classical and semi-classical energy states of relativistic electrons bounded by a massive and charged core with the charge-mass-radio Q/M and macroscopic radius R_c are discussed. We show that the energies of semi-classical (bound) states can be much smaller than the negative electron mass-energy (-mc^2), and energy-level crossing to negative energy continuum occurs. Electron-positron pair production takes place by quantum tunneling, if these bound states are not occupied. Electrons fill into these bound states and positrons go to infinity. We explicitly calculate the rate of pair-production, and compare it with the rates of electron-positron production by the Sauter-Euler-Heisenberg-Schwinger in a constant electric field. In addition, the pair-production rate for the electro-gravitational balance ratio Q/M = 10^{-19} is much larger than the pair-production rate due to the Hawking processes.

Remo Ruffini; She-Sheng Xue

2011-06-24T23:59:59.000Z

155

Squark pair production in the MSSM with explicit CP violation  

Science Conference Proceedings (OSTI)

We analyze effects of the CP-odd soft phases in the MSSM on the pair productions of colored superpartners in pp collisions at the LHC energies. We find that, among all pair-production processes, those of the scalar quarks in the first and second generations are particularly sensitive to the CP-odd phases, more precisely, to the phases of the gluinos and neutralinos. We compute pair-production cross sections, classify various production modes according to their dependencies on the gluino and neutralino phases, perform a detailed numerical analysis to determine individual as well as total cross sections, and give a detailed discussion of 2. electric dipole moment (EDM) bounds. We find that pair productions of first and second generation squarks serve as a viable probe of the CP violation sources in the gaugino sector of the theory even if experiments cannot determine chirality, flavor and electric charge of the squarks produced.

Alan, Ahmet T. [Department of Physics, Abant Izzet Baysal University, TR14280 (Turkey); Cankocak, Kerem [Department of Physics, Mugla University, TR48000 (Turkey); Demir, Durmus A. [Department of Physics, Izmir Institute of Technology, IZTECH, TR35430 (Turkey)

2007-05-01T23:59:59.000Z

156

Evolution of Fermion Pairing from Three to Two Dimensions  

E-Print Network (OSTI)

We follow the evolution of fermion pairing in the dimensional crossover from three-dimensional to two-dimensional as a strongly interacting Fermi gas of [superscript 6]Li atoms becomes confined to a stack of two-dimensional ...

Sommer, Ariel Tjodolv

157

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

Science Conference Proceedings (OSTI)

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

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

2012-10-15T23:59:59.000Z

158

Threshold energy surface and Frenkel-pair resistivity for Cu  

Science Conference Proceedings (OSTI)

In-situ electrical resistivity damage-rate measurements in the high voltage electron microscope have been used to study electron-irradiation-induced defect production in copper single crystals at T and surrounded by regions of much higher threshold energy. The corresponding damage function exhibits a plateau of 0.6 Frenkel pairs. the present results imply a Frenkel pair resistivity for C of (2.75/sub -0.2//sup +0.6/) x ..cap omega..-cm.

King, W.E.; Merkle, K.L.; Meshii, M.

1982-01-01T23:59:59.000Z

159

Scaling quark gluon plasma by HBT interferometry with lepton pairs  

E-Print Network (OSTI)

We study the intensity interferometry with lepton pairs for nuclear collisions at RHIC and LHC energies. It is argued that the invariant mass dependence of HBT radii extracted from the correlation functions of dilepton pairs can be used as an efficient tool to scale the size and life time of the quark gluon plasma expected to be formed in nuclear collisions at RHIC and LHC. Quantitatively different magnitudes of HBT radii are obtained at RHIC and LHC indicating stronger radial flow at LHC.

Payal Mohanty; Jan-e Alam

2012-02-10T23:59:59.000Z

160

Enhanced Schwinger's pair production in many-center systems  

E-Print Network (OSTI)

Electron-positron pair production is considered for many-center systems with multiple bare nuclei immersed in a constant electric field. It is shown that there are two distinct regimes where the pair production rate is enhanced. At small interatomic distance, the effective charge of the nuclei approaches the critical charge where the ground state dives into the negative continuum. This facilitates the transition from the negative to the positive energy states, which in turns, increases the pair production rate. At larger atomic distance, the enhancement is due to the crossing of resonances and the pair production proceeds by the Resonantly Enhanced Pair Production (REPP) mechanism. These processes are studied within a simple one-dimensional model. A numerical method is developed to evaluate the transmission coefficient in relativistic quantum mechanics, which is required in the calculation of the pair production rate. The latter is evaluated for systems with many (up to five) nuclei. It is shown that the production rate for many-center systems can reach a few orders of magnitude above Schwinger's tunnelling result in a static field.

François Fillion-Gourdeau; Emmanuel Lorin; André D. Bandrauk

2013-05-24T23:59:59.000Z

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


161

Photon Splitting and Pair Conversion in Strong Magnetic Fields  

E-Print Network (OSTI)

The magnetospheres of neutron stars provide a valuable testing ground for as-yet unverified theoretical predictions of quantum electrodynamics (QED) in strong electromagnetic fields. Exhibiting magnetic field strengths well in excess of a TeraGauss, such compact astrophysical environments permit the action of exotic mechanisms that are forbidden by symmetries in field-free regions. Foremost among these processes are single-photon pair creation, where a photon converts to an electron-positron pair, and magnetic photon splitting, where a single photon divides into two of lesser energy via the coupling to the external field. The pair conversion process is exponentially small in weak fields, and provides the leading order contribution to vacuum polarization. In contrast, photon splitting possesses no energy threshold and can operate in kinematic regimes where the lower order pair conversion is energetically forbidden. This paper outlines some of the key physical aspects of these processes, and highlights their manifestation in neutron star magnetospheres. Anticipated observational signatures include profound absorption turnovers in pulsar spectra at gamma-ray wavelengths. The shapes of these turnovers provide diagnostics on the possible action of pair creation and the geometrical locale of the photon emission region. There is real potential for the first confirmation of strong field QED with the new GLAST mission, to be launched by NASA in 2008. Suppression of pair creation by photon splitting and its implications for pulsars is also discussed.

Matthew G. Baring

2008-04-05T23:59:59.000Z

162

Plasmadynamics and ionization kinetics of thermionic energy conversion  

DOE Green Energy (OSTI)

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

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

1982-02-01T23:59:59.000Z

163

Table  

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

b(E) 10 6 cm 2 g -1 for Sodium nitrate NaNO 3 ZA 0.49415 E GeV b brems b pair b nucl b tot 2. 0.3298 0.1482 0.4566 0.9346 5. 0.4470 0.3631 0.4840 1.2941 10. 0.5431...

164

Table  

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

b(E) 10 6 cm 2 g -1 for Chlorine gas (Cl 2 ), Z 17, A 35.453(2) E GeV b brems b pair b nucl b tot 2. 0.5866 0.2765 0.4289 1.2920 5. 0.7980 0.6769 0.4568 1.9317 10....

165

Table  

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

b(E) 10 6 cm 2 g -1 for Liquid chlorine (Cl 2 ), Z 17, A 35.453(2) E GeV b brems b pair b nucl b tot 2. 0.5866 0.2765 0.4289 1.2920 5. 0.7980 0.6769 0.4568 1.9317 10....

166

Table  

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

Methane based) ZA 0.54993 E GeV b brems b pair b nucl b tot 2. 0.2587 0.1125 0.4738 0.8450 5. 0.3510 0.2787 0.5012 1.1309 10. 0.4276 0.4232 0.4859 1.3367 20. 0.5086 0.5806...

167

Table  

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

b(E) 10 6 cm 2 g -1 for Compact bone (ICRU) ZA 0.53010 E GeV b brems b pair b nucl b tot 2. 0.3535 0.1593 0.4614 0.9742 5. 0.4801 0.3928 0.4889 1.3618 10. 0.5841 0.5875...

168

Table  

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

b(E) 10 6 cm 2 g -1 for Plutonium, Z 94, A 244.06420(4) E GeV b brems b pair b nucl b tot 2. 2.1316 0.2707 0.3572 2.7595 5. 2.9643 1.9434 0.3812 5.2888 10. 3.6451...

169

Table  

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

b(E) 10 6 cm 2 g -1 for Plutonium dioxide (PuO 2 ) ZA 0.40583 E GeV b brems b pair b nucl b tot 2. 1.9169 0.2552 0.3693 2.5414 5. 2.6644 1.7544 0.3937 4.8124 10. 3.2756...

170

Table  

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

b(E) 10 6 cm 2 g -1 for Technetium, Z 43, A 97.90722(3) E GeV b brems b pair b nucl b tot 2. 1.2093 0.5181 0.3896 2.1169 5. 1.6623 1.4129 0.4163 3.4915 10. 2.0305...

171

Table  

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

b(E) 10 6 cm 2 g -1 for Benzene C 6 H 6 ZA 0.53769 E GeV b brems b pair b nucl b tot 2. 0.2319 0.0995 0.4765 0.8079 5. 0.3146 0.2475 0.5035 1.0656 10. 0.3835 0.3777...

172

Table  

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

b(E) 10 6 cm 2 g -1 for Butane (C 4 H 10 ) ZA 0.59497 E GeV b brems b pair b nucl b tot 2. 0.2191 0.0928 0.4841 0.7961 5. 0.2977 0.2326 0.5114 1.0417 10. 0.3637 0.3582...

173

Table  

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

b(E) 10 6 cm 2 g -1 for Thorium, Z 90, A 232.03806(2) E GeV b brems b pair b nucl b tot 2. 2.0665 0.3212 0.3589 2.7466 5. 2.8718 1.9386 0.3831 5.1934 10. 3.5299 3.1965...

174

Table  

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

b(E) 10 6 cm 2 g -1 for Liquid propane (C 3 H 8 ) ZA 0.58962 E GeV b brems b pair b nucl b tot 2. 0.2179 0.0921 0.4849 0.7949 5. 0.2961 0.2311 0.5122 1.0394 10. 0.3618...

175

Table  

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

b(E) 10 6 cm 2 g -1 for Propane (C 3 H 8 ) ZA 0.58962 E GeV b brems b pair b nucl b tot 2. 0.2179 0.0921 0.4849 0.7949 5. 0.2961 0.2311 0.5122 1.0394 10. 0.3618 0.3563...

176

Table  

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

b(E) 10 6 cm 2 g -1 for Tissue-equivalent gas (Propane based) ZA 0.55027 E GeV b brems b pair b nucl b tot 2. 0.2506 0.1085 0.4751 0.8342 5. 0.3400 0.2692 0.5024 1.1116...

177

Table  

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

b(E) 10 6 cm 2 g -1 for Rhenium, Z 75, A 186.207(1) E GeV b brems b pair b nucl b tot 2. 1.8307 0.4713 0.3667 2.6686 5. 2.5366 1.8861 0.3916 4.8143 10. 3.1125 2.9839...

178

Table  

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

b(E) 10 6 cm 2 g -1 for Carbon (graphite), Z 6, A 12.0107(8) E GeV b brems b pair b nucl b tot 2. 0.2422 0.1049 0.4703 0.8175 5. 0.3282 0.2595 0.4971 1.0848 10. 0.3994...

179

Table  

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

b(E) 10 6 cm 2 g -1 for Carbon (amorphous), Z 6, A 12.0107(8) E GeV b brems b pair b nucl b tot 2. 0.2422 0.1049 0.4703 0.8175 5. 0.3282 0.2595 0.4971 1.0848 10. 0.3994...

180

Table  

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

b(E) 10 6 cm 2 g -1 for Carbon (compact), Z 6, A 12.0107(8) E GeV b brems b pair b nucl b tot 2. 0.2422 0.1049 0.4703 0.8175 5. 0.3282 0.2595 0.4971 1.0848 10. 0.3994...

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


181

Table  

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

b(E) 10 6 cm 2 g -1 for Carbon (gem diamond), Z 6, A 12.0107(8) E GeV b brems b pair b nucl b tot 2. 0.2422 0.1049 0.4703 0.8175 5. 0.3282 0.2595 0.4971 1.0848 10....

182

Effects of prenatal exposure to ionizing radiation  

SciTech Connect

Prenatal exposure to ionizing radiation induces some effects that are seen at birth and others that cannot be detected until later in life. Data from A-bomb survivors in Hiroshima and Nagasaki show a diminished number of births after exposure under 4 wk of gestational age. Although a wide array of congenital malformations has been found in animal experimentation after such exposure to x rays, in humans only small head size (exposure at 4-17 wk) and mental retardation (exposure primarily at 8-15 wk) have been observed. In Hiroshima, small head size occurred after doses of 0.10-0.19 Gy or more, and an excess of mental retardation at 0.2-0.4 Gy or more. Intelligence test scores were reduced among A-bomb survivors exposed at 8-15 wk of gestational age by 21-29 IQ points per Gy. Other effects of in-utero exposure to atomic radiation include long-lasting complex chromosome abnormalities.

Miller, R.W. (National Cancer Institute, Bethesda, MD (USA))

1990-07-01T23:59:59.000Z

183

Dosimetry for non-ionizing radiation  

SciTech Connect

Several commercially available phosphor-teflon dosimeters were subjected to thermal fade studies. The thermoluminescence dosimetry (TLD) tags were washed and air dried prior to each ionizing radiation pretreatment. Readings made over 3 weeks on the CaF2:Mn and CaF2:Dy TLD tags did not produce measurable thermal-fade characteristics for the 22 to 31/sup 0/C temperature range. Nonionizing radiation treatments were at 2.45 GHz. While the results obtained did demonstrate decreases in signal levels over time and temperature changes, the patterns were not smooth, making it impossible to establish differences in TLD readings as quantitative measures of temperature differences which could serve as measures of long-term exposures to nonionizing radiation. The authors concluded that, due to the irregularities that existed in the thermal fade characteristics, the dosimeter would not be suitable for quantifying exposures to nonionizing radiation. There was significant potential in the device, however, as an indicator of radiation leakage or exposure.

Fanslow, G.E.

1981-03-01T23:59:59.000Z

184

Highly ionized atoms in tokamak discharges  

DOE Green Energy (OSTI)

Tokamak discharges are characterized by electron densities usually approximately 0.3 to 1.0 x 10/sup 14/ cm/sup -3/ and temperatures from a few hundred eV to several keV. In addition to the working gas (H or He), the plasma normally contains some light impurities (approximately 10/sup 12/ cm/sup -3/ O or C) that are completely stripped except at the outer periphery, and heavier elements from the vacuum wall and current-aperture limiter (Fe, Cr, Ni, W, Mo and others, approximately 10/sup 10/-10/sup 11/ cm/sup -3/) that remain partly stripped, hence relatively strongly radiating, throughout the discharge. Other elements, especially noble gases, may be deliberately added for diagnostic purposes. Resonance lines of Fe and Ar in the beryllium and lithium sequences, of Fe, Kr, and Mo in the magnesium and sodium sequences, and of Mo and Xe in the zinc and copper sequences have been used for rough determination of plasma composition. Since crucial plasma characteristics such as temperature and confinement time are sensitively affected by the local composition, it is essential to improve the available atomic data necessary for more accurate analysis: wavelengths, transition probabilities, excitation, ionization and recombination rates, especially for the heavier elements.

Hinnov, E.

1976-05-01T23:59:59.000Z

185

Ionization cooling in the muon collider  

SciTech Connect

The muon beams in a high luminosity muon collider are produced with a very large emittance. The process of ionization cooling offers a method for reducing the 6-dimensional normalized emittance of the beam by a factor of {approx} 10{sup 6}. A simple analytic theory has been developed that demonstrates the dependence of the net cooling on various experimental parameters. The simple theory has been checked and realistic arrangements have been examined using Monte Carlo simulations. Transverse cooling of the initial beam can be achieved using passive Li absorbers in a FOFO lattice. The last factor of 10 in transverse cooling probably requires the use of current-carrying Li lenses. Efficient longitudinal cooling requires the use of wedge shaped absorbers in a dispersive section of the beam line. An example, multi-stage cooling scenario has been developed that meets the requirements of the muon collider. Preliminary designs have been made of solenoids for use in the FOFO lattice and of solenoids and dipoles for use in the emittance exchange sections. Detailed simulation work, farther optimization, and preparations for experimental demonstrations of critical components are currently in progress.

Fernow, R.C.; Gallardo, J.C.; Kirk, H.G.; Palmer, R.B. [and others

1996-10-01T23:59:59.000Z

186

Ionizing wet scrubber for air pollution control  

Science Conference Proceedings (OSTI)

Air pollution control equipment manufacturers are continually developing sophisticated systems designed to dramatically reduce plant emissions. One such system, the ionizing wet scrubber (IWS), has demonstrated outstanding air pollution control characteristics while meeting the challenge of energy efficiency. The IWS system removes fine solid and liquid particulate down to 0.05 micron at high collection efficiencies and low energy comsumption. It also simultaneously removes noxious, corrosive and odor-bearing gases from flue gas streams as well as coarse particulate matter above 1 micron in diameter. Due to its simplified design and low pressure drop, operating energy costs of the IWS are only a fraction of those for alternative air pollution control equipment. Pressure drop through a single-stage IWS is only 0.5 to 1.5 in. Water (125 to 374 pa) column and is controlled primarily by pressure drop through the wet scrubber section. Total system energy usage is approximately 2.0-2.5 bhp/1,000 actual ft/sup 3//min (0.7-0.9 kw/m/sup 3//min) for a single-stage IWS and 4.0-5.0 bhp/1,000 actual ft/sup 3//min for a two-stage installation. These energy requirements represent a significant savings as opposed to other air pollution control systems such as Venturi scrubbers.

Sheppard, S.V.

1986-02-01T23:59:59.000Z

187

e+e- pair production from 10 GeV to 10 ZeV  

E-Print Network (OSTI)

e + e ? Pair Production from 10 GeV to 10 ZeV Spencer R.very high energies, pair production (? ? e + e ? ) exhibitsatoms reduces the pair production cross section considerably

Klein, Spencer R.

2004-01-01T23:59:59.000Z

188

Schwinger pair production in AdS2  

E-Print Network (OSTI)

We analyze the pair production of charged particles in two-dimensional Anti-de Sitter space (AdS_2) with a constant, uniform electric field. We compute the production rate both at a semi-classical level, viewing Schwinger pair production as a tunneling event, and at the full quantum level, by extracting the imaginary part of the one-loop amplitude. In contrast to the usual Schwinger pair production in flat space, pair production in AdS_2 requires a sufficiently large electric field E^2> M^2+1/4 in order to overcome the confining effect of the AdS geometry -- put in another way, the presence of an electric field E raises the Breitenlohner-Freedman bound to M^2 > -1/4 + E^2. For E greater than this threshold, the vacuum is unstable to production of charged pairs in the bulk. We expect our results to be helpful in constructing supersymmetric AdS_2 X S^2 perturbative string vacua, which enter in the near-horizon limit of extremal charged black holes. Although the generalized Breitenlohner-Freedman bound is obeyed in these cases, production of BPS particles at threshold is possible and relevant for AdS_2 fragmentation.

B. Pioline; J. Troost

2005-01-20T23:59:59.000Z

189

22.01 Introduction to Ionizing Radiation, Fall 2003  

E-Print Network (OSTI)

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

Coderre, Jeffrey A.

190

Determination of the first ionization potential of technetium  

Science Conference Proceedings (OSTI)

The first ionization potential (IP) of technetium (Tc) has been determined by evaluating Rydberg convergences toward the first ionization potential as well as toward two low-lying excited states of the singly charged Tc ion. The Rydberg states were excited and detected by applying multiphoton resonance ionization mass spectrometry (RIMS) on the long-lived isotope {sup 99g}Tc using a three-color excitation scheme. The observed Rydberg convergences yield a result for the first ionization potential of Tc V{sub IP}(Tc)=7.119380(32) eV. This precise value for V{sub IP}(Tc) is somewhat lower than the so far published data of 7.23 eV or 7.28 eV, dating back to the 1950s.

Mattolat, C.; Gottwald, T.; Raeder, S.; Rothe, S.; Schwellnus, F.; Wendt, K.; Thoerle-Pospiech, P.; Trautmann, N. [Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, D-55099 Mainz (Germany); Institut fuer Kernchemie, Johannes Gutenberg-Universitaet Mainz, D-55099 Mainz (Germany)

2010-05-15T23:59:59.000Z

191

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

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

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

192

Long slit spectroscopy of diffuse ionized gas in NGC 55  

E-Print Network (OSTI)

Spectroscopic measurements of emission line ratios and velocities are presented for ionized gas across the central plane of NGC 55, a late-type galaxy in the Sculptor group. The low metallicity in NGC 55 leads to relatively low line ratios of [S II]/H$\\alpha$ and [N II]/H$\\alpha$ for H II regions as well as the diffuse ionized gas. These are the first spectroscopical measurements of line ratios in ionized gas exterior to the stellar disc of NGC 55. Analysis of the line ratios and the relative velocities of different features suggests that photoionization is a plausible explanation for the ionization of this diffuse gas. The observed shell structures and the corresponding velocities support the idea of diffuse gas being pushed into the halo by supernova explosions and stellar winds.

B. Otte; R. -J. Dettmar

1999-01-21T23:59:59.000Z

193

Evolution of the Ionizing Background at High Redshifts  

E-Print Network (OSTI)

We use a Maximum-Likelihood analysis to constrain the value and evolution of the ionizing background for 2

Andrew Cooke; Brian Espey; Bob Carswell

1996-09-16T23:59:59.000Z

194

BSA 08-14: A Multi-Anode Ionization Chamber  

BSA 08-14: A Multi-Anode Ionization Chamber. BNL Reference Number: BSA 08-14. Patent Status: U.S. Patent Number 7,858,949 was issued on December 28, 2010

195

Experiments on electron-impact excitation and ionization of ions  

Science Conference Proceedings (OSTI)

The present review covers some of the fundamental aspects of electron-impact ionization. Highlights are described of some of the important experimental results which have been produced since 1981. (MOW)

Phaneuf, R.A.

1985-01-01T23:59:59.000Z

196

Conference report for nuclear fusion phenomena in ionized gases  

SciTech Connect

A summary of the Conference on Phenomena in Ionized Gases, held in Eindhoven, The Netherlands, is given. In particular, the format of the conference and the content of the review papers are summarized. (auth)

Porkolab, M.

1975-10-01T23:59:59.000Z

197

Ionized channel generation of an intense relativistic electron beam  

DOE Patents (OSTI)

An intense relativistic electron beam generator uses an ionized channel to guide electrons from a cathode past an anode to a remote location without the use of a foil.

Frost, C.A.; Leifeste, G.T.; Shope, S.L.

1986-03-31T23:59:59.000Z

198

Energy Efficiency and Fitness - A Complementary Pair | Department of  

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

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

199

Energy Efficiency and Fitness - A Complementary Pair | Department of  

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

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

200

Pair correlations of an expanding superfluid Fermi gas  

E-Print Network (OSTI)

The pair correlation function of an expanding gas is investigated with an emphasis on the BEC-BCS crossover of a superfluid Fermi gas at zero temperature. At unitarity quantum Monte Carlo simulations reveal the occurrence of a sizable bunching effect due to interactions in the spin up-down channel which, at short distances, is larger than that exhibited by thermal bosons in the Hanbury-Brown and Twiss effect. We propose a local equilibrium ansatz for the pair correlation function which we predict will remain isotropic during the expansion even if the trapping potential is anisotropic, contrary to what happens for non-interacting gases. This behavior is understood to be a consequence of the violation of scaling of the pair correlation function due to interactions.

C. Lobo; I. Carusotto; S. Giorgini; A. Recati; S. Stringari

2006-04-11T23:59:59.000Z

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


201

Mixed-Spin Pairing Condensates in Heavy Nuclei  

Science Conference Proceedings (OSTI)

We show that the Bogoliubov-de Gennes equations for nuclear ground-state wave functions support solutions in which the condensate has a mixture of spin-singlet and spin-triplet pairing. We find that such mixed-spin condensates do not occur when there are equal numbers of neutrons and protons, but only when there is an isospin imbalance. Using a phenomenological Hamiltonian, we predict that such nuclei may occur in the physical region within the proton dripline. We also solve the Bogoliubov-de Gennes equations with variable constraints on the spin-singlet and spin-triplet pairing amplitudes. For nuclei that exhibit this new pairing behavior, the resulting energy surface can be rather soft, suggesting that there may be low-lying excitations associated with the spin mixing.

Gezerlis, Alexandros; Luo, Y. L. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Bertsch, G. F. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195-1560 (United States)

2011-06-24T23:59:59.000Z

202

Semiclassical calculation of photon-stimulated Schwinger pair creation  

Science Conference Proceedings (OSTI)

We consider the electron-positron pair creation by a photon in an external constant electric field. The presented treatment is based on a purely quasiclassical calculation of the imaginary part of the on-shell photon polarization operator. By using this approach we find the pair production rate for photons with polarization parallel as well as orthogonal to the external electric field in the leading order in the parameter eE/m{sup 2}, which has been recently found by other methods. For the orthogonal polarization we also find a new contribution to the rate, which is leading in the ratio of the photon energy to the electron mass {omega}/m. We also reproduce by a purely geometrical calculation the exponential factor in the probability of the stimulated pair creation at arbitrary energy of the photon.

Monin, A.; Voloshin, M. B. [School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States); William I. Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

2010-04-15T23:59:59.000Z

203

LSP sneutrino decays into heavy standard model pairs  

E-Print Network (OSTI)

In bilinear R-parity violation (BRpV), in which the superpotential includes a bilinear term between the lepton doublet and the up-type Higgs superfields, a sneutrino LSP can decay into pairs of heavy standard model states: W's, Z's, tops or Higgs bosons. These finals states can dominate over the traditionally considered bottom pair final state. This would lead to unique and novel supersymmetric signals with each supersymmetric event possibly producing two pairs of these heavy standard model fields. We investigate this possibility and find that the branching ratio into heavier states dominates when the bilinear term is much smaller than the sneutrino vacuum expectation value for a given sneutrino flavor. When BRpV is the only source of neutrino masses these decays can only dominate for one of the sneutrino generations. Relaxing this constraint opens these channels for all three generations.

D. Aristizabal Sierra; D. Restrepo; S. Spinner

2012-12-13T23:59:59.000Z

204

Search for Squeezed-Pair Correlations at RHIC  

E-Print Network (OSTI)

Squeezed correlations of particle-antiparticle pairs, also called Back-to-Back Correlations, are predicted to appear if the hadron masses are modified in the hot and dense hadronic medium formed in high energy nucleus-nucleus collisions. Although well-established theoretically, the squeezed-particle correlations have not yet been searched for experimentally in high energy hadronic or heavy ion collisions, clearly requiring optimized forms to experimentally search for this effect. Within a non-relativistic treatment developed earlier we show that one promising way to search for the BBC signal is to look into the squeezed correlation function of pairs of phi-mesons at RHIC energies, plotted in terms of the average momentum of the pair, K12=(k1+k2)/2. This variable's modulus, 2|K12|, is the non-relativistic limit of the variable Q_bbc, introduced herewith. The squeezing effects on the HBT correlation function are also discussed.

Sandra S. Padula; O. Socolowski Jr.; T. Csorgo; M. I. Nagy

2008-05-02T23:59:59.000Z

205

The Propagation of Photons in the Dilute Ionized Gas  

E-Print Network (OSTI)

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.

Yijia Zheng

2013-05-02T23:59:59.000Z

206

The Propagation of Photons in the Dilute Ionized Gas  

E-Print Network (OSTI)

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.

Zheng, Yijia

2013-01-01T23:59:59.000Z

207

Cross sections for short pulse single and double ionization ofhelium  

SciTech Connect

In a previous publication, procedures were proposed for unambiguously extracting amplitudes for single and double ionization from a time-dependent wavepacket by effectively propagating for an infinite time following a radiation pulse. Here we demonstrate the accuracy and utility of those methods for describing two-photon single and one-photon double ionization of helium. In particular it is shown how narrow features corresponding to autoionizing states are easily resolved with these methods.

Palacios, Alicia; Rescigno, Thomas N.; McCurdy, C. William

2007-11-27T23:59:59.000Z

208

Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation  

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

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

209

Muon Bremsstrahlung and Muonic Pair Production in Air Showers  

E-Print Network (OSTI)

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

A. Cillis; S. J. Sciutto

2000-06-08T23:59:59.000Z

210

Entanglement dynamics of photon pairs emitted from quantum dots  

Science Conference Proceedings (OSTI)

We present a model that describes states of photon pairs, which have been generated by biexciton cascade decays of self-assembled quantum dots, the use of which yields a finding that agrees well with the experimental result. Furthermore, we calculate the concurrence and determine the temperature behavior associated with the so-called entanglement sudden death that prevents quantum dots emitting entangled photon pairs at raised temperatures. The relationship between the fine-structure splitting and the sudden death temperature is also provided.

Zou, Yang; Gong, Ming; Li, Chuan-Feng; Chen, Geng; Tang, Jian-Shun; Guo, Guang-Can [Key Laboratory of Quantum Information, University of Science and Technology of China, CAS, Hefei 230026 (China)

2010-06-15T23:59:59.000Z

211

Magnetic moments of T=3/2 mirror pairs  

Science Conference Proceedings (OSTI)

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

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

2010-12-15T23:59:59.000Z

212

Counting the number of correlated pairs in a nucleus  

E-Print Network (OSTI)

We suggest that the number of correlated nucleon pairs in an arbitrary nucleus can be estimated by counting the number of proton-neutron, proton-proton, and neutron-neutron pairs residing in a relative $S$ state. We present numerical calculations of those amounts for the nuclei $^{4}$He, $^{9}$Be, $ ^{12}$C, $ ^{27}$Al, $ ^{40}$Ca, $ ^{48}$Ca, $ ^{56}$Fe, $ ^{63}$Cu, $ ^{108}$Ag, and $ ^{197}$Au. The results are used to predict the values of the ratios of the per-nucleon electron-nucleus inelastic scattering cross section to the deuteron in the kinematic regime where correlations dominate.

Maarten Vanhalst; Wim Cosyn; Jan Ryckebusch

2011-05-05T23:59:59.000Z

213

Screening of nuclear pairing in nuclear and neutron matter  

E-Print Network (OSTI)

The screening potential in the $^1S_0$ and $^3S_1$ pairing channels in neutron and nuclear matter in different approximations is discussed. It is found that the vertex corrections to the potential are much stronger in nuclear matter than in neutron matter.

Caiwan Shen; Umberto Lombardo; Peter Schuck

2005-03-03T23:59:59.000Z

214

Interpreting motion events of pairs of moving objects  

Science Conference Proceedings (OSTI)

When accumulating large quantities of positional data with ubiquitous positioning techniques, methods are required that can efficiently make use of these data. This work proposes a representation that approximates motion events of pairs of objects. It ... Keywords: Change in direction, Motion events/patterns, Spatiotemporal reasoning

Björn Gottfried

2011-04-01T23:59:59.000Z

215

Solar absorption refrigeration system using new working fluid pairs  

Science Conference Proceedings (OSTI)

Absorption refrigeration systems powered by solar energy increasingly attract research interests in the last years. In this study, thermodynamic analyses for different working fluid pairs are performed. A computer simulation model has been developed ... Keywords: NH3-LiNO3, absorption, crystallization, generator, performance, refrigeration, solar energy

Jasim M. Abdulateef; Kamaruzzaman Sopian; M. A. Alghoul; Mohd Yusof Sulaiman; Azami Zaharim; Ibrahim Ahmad

2008-02-01T23:59:59.000Z

216

Radiative proton-antiproton annihilation to a lepton pair  

Science Conference Proceedings (OSTI)

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

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

2010-11-01T23:59:59.000Z

217

Pair Production of Tau Sneutrinos at Linear Colliders  

E-Print Network (OSTI)

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

Ari, V

2010-01-01T23:59:59.000Z

218

Singlet Free Energies of a Static Quark-Antiquark Pair  

E-Print Network (OSTI)

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.

Konstantin Petrov

2004-09-01T23:59:59.000Z

219

Secure SMS based automatic device pairing approach for mobile phones  

Science Conference Proceedings (OSTI)

Bluetooth is recognized as one of the efficient way of data transmission at short distances wirelessly. Despite the fact that Bluetooth is widely accepted wireless standard for data transmission, there are also some security issues associated with Bluetooth. ... Keywords: global system for mobiles (GSM), mobile device pairing, out of band (OOB) channel, short messaging service (SMS)

Shoohira Aftab, Amna Khalid, Asad Raza, Haider Abbas

2013-07-01T23:59:59.000Z

220

A Complementary Pair of Four-Terminal Silicon Synapses  

Science Conference Proceedings (OSTI)

We have developed a complementary pair of pFET and nFET floating-gate silicon MOS transistors for analog learning applications. The memory storage is nonvolatile; hot-electron ... Keywords: floating-gate MOSFET, silicon learning, synapse transistor

Chris Diorio; Paul Hasler; Bradley A. Minch; Carver Mead

1997-05-01T23:59:59.000Z

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


221

Set-sharing is redundant for pair-sharing  

Science Conference Proceedings (OSTI)

Although the usual goal of sharing analysis is to detect which pairs of variables share, the standard choice for sharing analysis is a domain that characterizes set-sharing. In this paper, we question, apparently for the first time, whether this domain ... Keywords: abstract interpretation, data-flow analysis, logic programming, sharing analysis

Roberto Bagnara; Patricia M. Hill; Enea Zaffanella

2002-04-01T23:59:59.000Z

222

Pairing Functions, Boolean Evaluation and Binary Decision Diagrams  

E-Print Network (OSTI)

A ``pairing function'' J associates a unique natural number z to any two natural numbers x,y such that for two ``unpairing functions'' K and L, the equalities K(J(x,y))=x, L(J(x,y))=y and J(K(z),L(z))=z hold. Using pairing functions on natural number representations of truth tables, we derive an encoding for Binary Decision Diagrams with the unique property that its boolean evaluation faithfully mimics its structural conversion to a a natural number through recursive application of a matching pairing function. We then use this result to derive {\\em ranking} and {\\em unranking} functions for BDDs and reduced BDDs. The paper is organized as a self-contained literate Prolog program, available at \\url{http://logic.csci.unt.edu/tarau/research/2008/pBDD.zip}. {\\em Keywords:} logic programming and computational mathematics, pairing/unpairing functions, encodings of boolean functions, binary decision diagrams, natural number representations of truth tables

Tarau, Paul

2008-01-01T23:59:59.000Z

223

Efficient device pairing using "Human-comparable" synchronized audiovisual patterns  

Science Conference Proceedings (OSTI)

"Pairing" is referred to as the operation of achieving authenticated key agreement between two human-operated devices over a short- or medium-range wireless communication channel (such as Bluetooth, WiFi). The devices are ad hoc in nature, i.e., they ...

Ramnath Prasad; Nitesh Saxena

2008-06-01T23:59:59.000Z

224

A pair of disjoint 3-GDDs of type gtu1  

Science Conference Proceedings (OSTI)

Pairwise disjoint 3-GDDs can be used to construct some optimal constant-weight codes. We study the existence of a pair of disjoint 3-GDDs of type g t u 1 and establish that its necessary conditions ... Keywords: 05B05, Constant-composition code, Constant-weight code, Disjoint, Group divisible design, Idempotent Latin square, Modified group divisible design, Resolvable

Yanxun Chang; Yeow Meng Chee; Junling Zhou

2011-07-01T23:59:59.000Z

225

PAIR DISTRIBUTION FUNCTIONS OF BACTERIORHODOPSIN AND RHODOPSIN IN MODEL  

E-Print Network (OSTI)

information upon simple visual inspection. Recently methods have been devised to quantitate the distribution techniques (Donnell and Finegold, 1981; Pearson et al., 1979). In the present work we employ the pair distribution function (Perelson, 1978; Gershon et al., 1979; Markovics et al., 1974) to obtain a quantitative

226

Monte Carlo Photoionization Simulations of Diffuse Ionized Gas  

E-Print Network (OSTI)

We demonstrate that the observed increase of some nebular line ratios with height above the midplane in the diffuse ionized gas (DIG) in the Milky Way and other galaxies is a natural consequence of the progressive hardening of the radiation field far from the midplane ionizing sources. To obtain increasing temperatures and line ratios away from the midplane, our photoionization simulations of a multi-component interstellar medium do not require as much additional heating (over and above that from photoionization) as previous studies that employed one dimensional, spherically averaged models. Radiation leaking into the DIG from density bounded H II regions is generally harder in the H-ionizing continuum and has its He-ionizing photons suppressed compared to the ionizing source of the H II region. In line with other recent investigations, we find that such leaky H II region models can provide elevated temperatures and line ratios, and a lower He+ fraction in the DIG. For a composite model representing the relat...

Wood, K; Wood, Kenneth; Mathis, John S.

2004-01-01T23:59:59.000Z

227

Monte Carlo Photoionization Simulations of Diffuse Ionized Gas  

E-Print Network (OSTI)

We demonstrate that the observed increase of some nebular line ratios with height above the midplane in the diffuse ionized gas (DIG) in the Milky Way and other galaxies is a natural consequence of the progressive hardening of the radiation field far from the midplane ionizing sources. To obtain increasing temperatures and line ratios away from the midplane, our photoionization simulations of a multi-component interstellar medium do not require as much additional heating (over and above that from photoionization) as previous studies that employed one dimensional, spherically averaged models. Radiation leaking into the DIG from density bounded H II regions is generally harder in the H-ionizing continuum and has its He-ionizing photons suppressed compared to the ionizing source of the H II region. In line with other recent investigations, we find that such leaky H II region models can provide elevated temperatures and line ratios, and a lower He+ fraction in the DIG. For a composite model representing the relative spectral types of O stars in the solar neighbourhood, we find that additional heating less than 1.0E-26 n_e ergs/s/cm^3 can reproduce the observed elevated line ratios in the DIG. This additional heating is considerably less than previous estimates due to the natural hardening of the radiation field reaching large heights in our simulations.

Kenneth Wood; John S. Mathis

2004-02-17T23:59:59.000Z

228

Ionization-Based Multi-directional Flow Sensor  

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

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

229

Novel target configurations for selective ionization state studies in molybdenum  

Science Conference Proceedings (OSTI)

Details of experiments aimed at achieving low ionization state selectivity in molybdenum are presented. Targets are excited with a 10 J CO{sub 2} laser and the resultant VUV spectrum (300--700 {Angstrom}) has been studied. Combinations of focal spot size, target depth, and target geometries are compared. Simple attenuation of energy is shown not to vary ionization stage composition significantly. Experiments conducted with grazing incidence targets result only in a hot plasma. Modular targets with cooling cylinders of various radii demonstrated good selectivity of the ionization states, but with low absolute signals. Finally, results from combinations of focal spot adjustment and radiative cooling illustrate increased control over desired plasma temperature and density for spectroscopic studies of molybdenum. 7 refs., 14 figs.

Ilcisin, K.J.; Feldman, U.; Schwob, J.L.; Wouters, A. (Princeton Univ., NJ (USA). Plasma Physics Lab.); Suckewer, S. (Princeton Univ., NJ (USA). Plasma Physics Lab. Princeton Univ., NJ (USA). Dept. of Mechanical and Aerospace Engineering)

1990-03-01T23:59:59.000Z

230

Rayleigh-Taylor Instability at Ionization Fronts: Perturbation Analysis  

E-Print Network (OSTI)

The linear growth rate of the Rayleigh-Taylor instability (RTI) at ionization fronts is investigated via perturbation analysis in the limit of incompressible fluids. In agreement with previous numerical studies is found that absorption of ionizing radiation inside the HII region due to hydrogen recombinations suppresses the growth of instabilities. In the limit of a large density contrast at the ionization front the RTI growth rate has the simple analytical solution n=-nur+(nur^2+gk)^(1/2), where nur is the hydrogen recombination rate inside the HII region, k is the perturbation's wavenumber and g is the effective acceleration in the frame of reference of the front. Therefore, the growth of surface perturbations with wavelengths lambda >> lambda_{cr} = 2\\pi g/nur^2 is suppressed by a factor (lambda_{cr}/4lambda)^(1/2) with respect to the non-radiative incompressible RTI. Implications on stellar and black hole feedback are briefly discussed.

Ricotti, Massimo

2013-01-01T23:59:59.000Z

231

The kinematics of the diffuse ionized gas in NGC 4666  

E-Print Network (OSTI)

The global properties of the interstellar medium with processes such as infall and outflow of gas and a large scale circulation of matter and its consequences for star formation and chemical enrichment are important for the understanding of galaxy evolution. In this paper we studied the kinematics and morphology of the diffuse ionized gas (DIG) in the disk and in the halo of the star forming spiral galaxy NGC 4666 to derive information about its kinematical properties. Especially, we searched for infalling and outflowing ionized gas. We determined surface brightness, radial velocity, and velocity dispersion of the warm ionized gas via high spectral resolution (R ~ 9000) Fabry-P\\'erot interferometry. This allows the determination of the global velocity field and the detection of local deviations from this verlocity field. We calculated models of the DIG distribution and its kinematics for comparison with the measured data. In this way we determined fundamental parameters such as the inclination and the scale h...

Voigtländer, Pierre; Marcelin, Michel; Bomans, Dominik J; Dettmar, Ralf-Jürgen

2013-01-01T23:59:59.000Z

232

Scaling Cross Sections for Ion-atom Impact Ionization  

DOE Green Energy (OSTI)

The values of ion-atom ionization cross sections are frequently needed for many applications that utilize the propagation of fast ions through matter. When experimental data and theoretical calculations are not available, approximate formulas are frequently used. This paper briefly summarizes the most important theoretical results and approaches to cross section calculations in order to place the discussion in historical perspective and offer a concise introduction to the topic. Based on experimental data and theoretical predictions, a new fit for ionization cross sections is proposed. The range of validity and accuracy of several frequently used approximations (classical trajectory, the Born approximation, and so forth) are discussed using, as examples, the ionization cross sections of hydrogen and helium atoms by various fully stripped ions.

Igor D. Kaganovich; Edward Startsev; Ronald C. Davidson

2003-06-06T23:59:59.000Z

233

Spatially resolved thermal desorption/ionization coupled with mass spectrometry  

DOE Patents (OSTI)

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

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

2013-02-26T23:59:59.000Z

234

Collision-induced dissociation reactions and pulsed field ionization photoelectron  

DOE Green Energy (OSTI)

This report summarized the four parts of the research study and describes the general conclusions. Individual chapters have been removed for separate processing. The chapter titles are: A study of the dissociation of CH{sub 3}SH{sup +} by collisional activation: Observation of non-statistical behavior; High resolution vacuum ultraviolet pulsed field ionization photoelectron band for OCS{sup +}(X{sup 2}{Pi}): An experimental and theoretical study; Rotationally resolved pulsed field ionization photoelectron bands of H{sub 2}{sup +} ({Chi}{sup 2}{Sigma}{sup +}{sub g}, v{sup +} = 0--18); and Rotationally resolved pulsed field ionization photoelectron bands of HD{sup +} ({Chi}{sup 2}{Sigma}{sup +}, v{sup +} = 0--21).

Stimson, S.

1999-02-12T23:59:59.000Z

235

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

Science Conference Proceedings (OSTI)

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

Isselhardt, B H

2011-09-06T23:59:59.000Z

236

Schwinger Vacuum Pair Production in Chirped Laser Pulses  

E-Print Network (OSTI)

The recent developments of high intensity ultra-short laser pulses have raised the hopes of observing Schwinger vacuum pair production which is one of the important non-perturbative phenomena in Quantum electrodynamics (QED). The quantitative analysis of realistic high intensity laser pulses is vital for understanding the effect of the field parameters on the momentum spectrum of the produced particles. In this study, we analyze chirped laser pulses with a sub-cycle structure, and investigate the effects of the chirp parameter on the momentum spectrum of the produced particles. The combined effect of the chirp and carrier phase of the laser pulse is also analyzed. These effects are qualitatively explained by investigating the turning point structure of the potential within the framework of the complex WKB scattering approach to pair production.

Cesim K. Dumlu

2010-06-19T23:59:59.000Z

237

Pair creation by a photon in an electric field  

E-Print Network (OSTI)

The process of pair creation by a photon in a constant and homogeneous electric field is investigated basing on the polarization operator in the field. The total probability of the process is found in a relatively simple form. At high energy the quasiclassical approximation is valid. The corrections to the standard quasiclassical approximation (SQA) are calculated. In the region relatively low photon energies, where SQA is unapplicable, the new approximation is used. It is shown that in this energy interval the probability of pair creation by a photon in electric field exceeds essentially the corresponding probability in a magnetic field. This approach is valid at the photon energy much larger than "vacuum" energy in electric field: $\\omega\\gg eE/m$. For smaller photon energies the low energy approximation is developed. At $\\omega\\ll eE/m$ the found probability describes the absorption of soft photon by the particles created by an electric field.

V. N. Baier; V. M. Katkov

2009-12-29T23:59:59.000Z

238

Threshold energy surface and Frenkel-pair resistivity for Cu  

SciTech Connect

In-situ electrical resistivity damage-rate measurements in the high voltage electron microscope have been used to study electron-irradiation-induced defect production in copper single crystals at T < 10/sup 0/K. Analysis of the directional and energy dependence yields a threshold energy surface that is significantly different from those of previous investigations: two pockets of low threshold energy centered at <100> and <110> surrounded by regions of much higher threshold energy. The corresponding damage function exhibits a plateau of 0.6 Frenkel pairs. the present results imply a Frenkel pair resistivity for C of (2.75/sub -0.2//sup +0.6/) x ..cap omega..-cm.

King, W.E.; Merkle, K.L.; Meshii, M.

1982-01-01T23:59:59.000Z

239

Electron and positron pair production of compact stars  

E-Print Network (OSTI)

Neutral stellar core at or over nuclear densities is described by a positive charged baryon core and negative charged electron fluid since they possess different masses and interactions. Based on a simplified model of a gravitationally collapsing or pulsating baryon core, we approximately integrate the Einstein-Maxwell equations and the equations for the number and energy-momentum conservation of complete degenerate electron fluid. We show possible electric processes that lead to the production of electron-positron pairs in the boundary of a baryon core and calculate the number and energy of electron-positron pairs. This can be relevant for understanding the energetic sources of supernovae and gamma-ray bursts.

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

2011-10-04T23:59:59.000Z

240

Microwave and THz sensing using slab-pair-based metamaterials  

SciTech Connect

In this work the sensing capability of an artificial magnetic metamaterial based on pairs of metal slabs is demonstrated, both theoretically and experimentally, in the microwave regime. The demonstration is based on transmission measurements and simulations monitoring the shift of the magnetic resonance frequency as one changes a thin dielectric layer placed between the slabs of the pairs. Strong dependence of the magnetic resonance frequency on both the permittivity and the thickness of the dielectric layer under detection was observed. The sensitivity to the dielectrics? permittivity (?) is larger for dielectrics of low ? values, which makes the approach suitable for sensing organic materials also in the THz regime. The capability of our approach for THz sensing is also demonstrated through simulations.

Kenanakis, G.; Shen, Nianhai; Mavidis, Ch.; Katsarakis, N.; Kafesaki, M.; Soukoulis, Costas M.; Economou, E.N.

2012-10-15T23:59:59.000Z

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


241

Direct measurements of the ionization profile in krypton helicon plasmas  

SciTech Connect

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

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

2012-12-15T23:59:59.000Z

242

Nonclassical correlation of cascaded photon pairs emitted from quantum dots  

SciTech Connect

We studied the quantum correlation of the photon pairs generated by biexciton cascade decays of self-assembled quantum dots, and determined the correlation sudden-change temperature, which is shown to be independent of the background noise, far lower than the entanglement sudden-death temperature, and therefore, easier to be observed in experiments. The relationship between the fine-structure splitting and the sudden-change temperature is also provided.

Li, Chuan-Feng; Zou, Yang; Xu, Jin-Shi; Ge, Rong-Chun; Guo, Guang-Can [Key Laboratory of Quantum Information, University of Science and Technology of China, CAS, Hefei 230026 (China)

2011-11-15T23:59:59.000Z

243

Exact Solution of the Isovector Neutron-Proton Pairing Hamiltonian  

SciTech Connect

The complete exact solution of the T=1 neutron-proton pairing Hamiltonian is presented in the context of the SO(5) Richardson-Gaudin model with nondegenerate single-particle levels and including isospin symmetry-breaking terms. The power of the method is illustrated with a numerical calculation for {sup 64}Ge for a pf+g{sub 9/2} model space which is out of reach of modern shell-model codes.

Dukelsky, J.; Errea, B.; Lerma, S.H. [Instituto de Estructura de la Materia, CSIC. Serrano 123, 28006 Madrid (Spain); Gueorguiev, V.G. [Lawrence Livermore National Laboratory, Livermore, California (United States); Institute of Nuclear Research and Nuclear Energy, BAS, Sofia 1784 (Bulgaria); Van Isacker, P. [Grand Accelerateur National d'Ions Lourds, BP 55027, F-14076 Caen Cedex 5 (France); Dimitrova, S. [Institute of Nuclear Research and Nuclear Energy, BAS, Sofia 1784 (Bulgaria)

2006-02-24T23:59:59.000Z

244

Top quark pair production cross section at the Tevatron  

SciTech Connect

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

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

2008-04-01T23:59:59.000Z

245

A compact neutron generator using a field ionization source  

Science Conference Proceedings (OSTI)

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.

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

2011-10-31T23:59:59.000Z

246

Weak Interaction Neutron Production Rates in Fully Ionized Plasmas  

E-Print Network (OSTI)

Employing the weak interaction reaction wherein a heavy electron is captured by a proton to produce a neutron and a neutrino, the neutron production rate for neutral hydrogen gases and for fully ionized plasmas is computed. Using the Coulomb atomic bound state wave functions of a neutral hydrogen gas, our production rate results are in agreement with recent estimates by Maiani {\\it et al}. Using Coulomb scattering state wave functions for the fully ionized plasma, we find a substantially enhanced neutron production rate. The scattering wave function should replace the bound state wave function for estimates of the enhanced neutron production rate on water plasma drenched cathodes of chemical cells.

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

2013-05-19T23:59:59.000Z

247

Partially Ionized Atmospheres of Neutron Stars with Strong Magnetic Fields  

DOE Green Energy (OSTI)

We construct hydrogen atmosphere models for strongly magnetized neutron stars in thermodynamic equilibrium, taking into account partial ionization. The presence of bound states affects the equation of state, absorption coefficients, and polarizability tensor of a strongly magnetized plasma. Therefore the partial ionization influences the polarization vectors and opacities of normal electromagnetic waves, and thus the spectra of outgoing radiation. Here we review a model suitable for the most typical neutron-star atmospheres and focus on the problems that remain to be solved for its extension to other atmospheric parameters.

Potekhin, A.

2005-01-28T23:59:59.000Z

248

Third-harmonic generation and multiphoton ionization spectroscopy  

SciTech Connect

Nonlinear phenomena, such as multiphoton excitation (MPE) processes leading to ionization and third-harmonic generation (THG) in gases have become the issue of extensive studies over recent years. Studies in rare gases in particular have resulted in several interesting observations in this respect. Thus, it has been established that three-photon resonantly enhanced multiphoton ionization (MPI) in the vicinity of states which are single photon optically coupled to the ground state may occur in efficient competition with THG. The present work demonstrates several new effects which may appear when third-harmonic radiation is present during MPI.

Fotakis, C.; Stockdale, J.A.D.; Proctor, M.J.

1987-01-01T23:59:59.000Z

249

Resonance enhancement of nonsequential double ionization by a magnetic field  

Science Conference Proceedings (OSTI)

We investigate nonsequential double ionization (NSDI) of helium by using an additional magnetic field parallel to the polarization of the laser pulse. By exploring the ability of a magnetic field for focusing the selected trajectories that contribute to the NSDI, we have found that the yield of NSDI, as a function of the magnetic-field strength, shows different behavior for different laser intensities. As a result, an additional magnetic field provides a way to identify that the NSDI mechanism of laser-assisted collision ionization begins to play an important role as the laser intensity increases.

Li Hongyun [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, Beijing 100871 (China); Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Chen Jing; Liu Jie [Center for Nonlinear Studies, Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Jiang Hongbing; Gong Qihuang [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, Beijing 100871 (China); Fu Panming; Wang Bingbing [Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Yan Zongchao [Department of Physics, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3 (Canada)

2011-01-15T23:59:59.000Z

250

Ionization Induced Trapping in a Laser Wakefield Accelerator  

Science Conference Proceedings (OSTI)

Experimental studies of electrons produced in a laser wakefield accelerator indicate trapping initiated by ionization of target gas atoms. Targets composed of helium and controlled amounts of various gases were found to increase the beam charge by as much as an order of magnitude compared to pure helium at the same electron density and decrease the beam divergence from 5.1+-1.0 to 2.9+-0.8 mrad. The measurements are supported by particle-in-cell modeling including ionization. This mechanism should allow generation of electron beams with lower emittance and higher charge than in preionized gas.

McGuffey, C.; Thomas, A. G. R.; Schumaker, W.; Matsuoka, T.; Chvykov, V.; Dollar, F. J.; Kalintchenko, G.; Yanovsky, V.; Maksimchuk, A.; Krushelnick, K.; Bychenkov, V. Yu.; Glazyrin, I. V.; Karpeev, A. V. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); P. N. Lebedev Physics Institute, Russian Academy of Science, Leninskii Prospect 53, Moscow 119991 (Russian Federation); RFNC-VNIITF, Snezhinsk 456770, Chelyabinsk region (Russian Federation)

2010-01-15T23:59:59.000Z

251

Charge Distribution about an Ionizing Electron Track in Liquid Helium  

E-Print Network (OSTI)

The dependence on an applied electric field of the ionization current produced by an energetic electron stopped in liquid helium can be used to determine the spatial distribution of secondary electrons with respect to their geminate partners. An analytic expression relating the current and distribution is derived. The distribution is found to be non-Gaussian with a long tail at larger distances.

G. M. Seidel; T. M. Ito; A. Ghosh; B. Sethumadhavan

2013-10-04T23:59:59.000Z

252

Three-photon above-threshold ionization of magnesium  

Science Conference Proceedings (OSTI)

Three-photon ionization cross sections from the ground state, and two-photon ionization from the 3 {sup 1}P(3s3p) state have been calculated for Mg in the region between the 3p and 4s ionization thresholds. These processes include an above-threshold ionization process for the last absorbed photon. We have used the Green's-function method in the Feshbach formalism and an L{sup 2} close coupling approach, with a basis of L{sup 2} integrable B-spline functions. We report the positions, widths, and assignments of a number of relevant {sup 1}P{sup o} and{sup 1}F{sup o} doubly excited Feshbach states. We also observe unusually high cross sections due to a bound-bound transition from the 3 {sup 1}S(3s{sup 2}) to the 3 {sup 1}P(3s3p) state, a core excitation process, and the population of an intermediate doubly excited state. Both total cross sections and angular distributions are reported.

Reber, A.; Berry, R.S. [Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637 (United States); Martin, F. [Departamento de Quimica C-9, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Bachau, H. [Centre des Lasers Intenses et Applications (UMR 5107 du CNRS), Universite de Bordeaux I, 351 Cours de la Liberation, F-33405 Talence (France)

2003-12-01T23:59:59.000Z

253

Functional Proteomic Pattern Identification under Low Dose Ionizing Radiation  

Science Conference Proceedings (OSTI)

The goal of this study is to explore and to understand the dynamic responses of signaling pathways to low dose ionizing radiation (IR). Low dose radiation (10 cGy or lower) affects several signaling pathways including DNA repair, survival, cell cycle, ... Keywords: low dose radiation, functional proteomics

Young Bun Kim; Jean Gao; Ying Dong; Chin-Rang Yang

2008-11-01T23:59:59.000Z

254

Parametric-Resonance Ionization Cooling of Muon Beams  

Science Conference Proceedings (OSTI)

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

V.S. Morozov, Ya.S. Derbenev, A. Afanasev, R.P. Johnson, B. Erdelyi, J.A. Maloney

2012-12-01T23:59:59.000Z

255

Parametric-resonance ionization cooling of muon beams  

Science Conference Proceedings (OSTI)

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

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

2012-12-21T23:59:59.000Z

256

Effects of a static electric field on nonsequential double ionization  

SciTech Connect

Using a three-dimensional semiclassical method, we perform a systematic analysis of the effects of an additional static electric field on nonsequential double ionization (NSDI) of a helium atom in an intense, linearly polarized laser field. It is found that the static electric field influences not only the ionization rate, but also the kinetic energy of the ionized electron returning to the parent ion, in such a way that, if the rate is increased, then the kinetic energy of the first returning electron is decreased, and vice versa. These two effects compete in NSDI. Since the effect of the static electric field on the ionization of the first electron plays a more crucial role in the competition, the symmetric double-peak structure of the He{sup 2+} momentum distribution parallel to the polarization of the laser field is destroyed. Furthermore, the contribution of the trajectories with multiple recollisions to the NSDI is also changed dramatically by the static electric field. As the static electric field increases, the trajectories with two recollisions, which start at the time when the laser and the static electric field are in the same direction, become increasingly important for the NSDI.

Li Hongyun [Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, Beijing 100871 (China); Wang Bingbing; Li Xiaofeng; Fu Panming [Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Chen Jing; Liu Jie [Center for Nonlinear Studies, Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Jiang Hongbing; Gong Qihuang [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, Beijing 100871 (China); Yan Zongchao [Department of Physics, University of New Brunswick, P.O. Box 4400, Fredericton, New Brunswick, E3B 5A3 (Canada); Research Academy of Science and Technology, Harbin Institute of Technology, Harbin 150001 (China)

2007-09-15T23:59:59.000Z

257

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

E-Print Network (OSTI)

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 ...

Velasquez-Heller, Luis Fernand

258

RF, Thermal and Structural Analysis of the 201.25 MHz Muon Ionization Cooling Cavity  

E-Print Network (OSTI)

THERMAL AND STRUCTURAL ANALYSIS OF THE 201.25 MHZ MUON IONIZATION COOLINGthe thermal performance of the cavity, including the coolingthermal and structural behavior of the prototype 201.25 MHz cavity for a muon ionization cooling

Virostek, S.; Li, D.

2005-01-01T23:59:59.000Z

259

RAYLEIGH-TAYLOR INSTABILITY IN PARTIALLY IONIZED COMPRESSIBLE PLASMAS  

Science Conference Proceedings (OSTI)

We study the modification of the classical criterion for the linear onset and growing rate of the Rayleigh-Taylor instability (RTI) in a partially ionized plasma in the two-fluid description. The plasma is composed of a neutral fluid and an electron-ion fluid, coupled by means of particle collisions. The governing linear equations and appropriate boundary conditions, including gravitational terms, are derived and applied to the case of the RTI in a single interface between two partially ionized plasmas. The limits of collisionless, no gravity, and incompressible fluids are checked before addressing the general case. We find that both compressibility and ion-neutral collisions lower the linear growth rate, but do not affect the critical threshold of the onset of the RTI. The configuration is always unstable when a lighter plasma is below a heavier plasma regardless the value of the magnetic field strength, the ionization degree, and the ion-neutral collision frequency. However, ion-neutral collisions have a strong impact on the RTI growth rate, which can be decreased by an order of magnitude compared to the value in the collisionless case. Ion-neutral collisions are necessary to accurately describe the evolution of the RTI in partially ionized plasmas such as prominences. The timescale for the development of the instability is much longer than in the classical incompressible fully ionized case. This result may explain the existence of prominence fine structures with life times of the order of 30 minutes. The timescales derived from the classical theory are about one order of magnitude shorter and incompatible with the observed life times.

Diaz, A. J. [Instituto de Astrofisica de Canarias, 38205, C/ Via Lactea, s/n, La Laguna, Tenerife (Spain); Soler, R. [Centre for Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, 3001 Leuven (Belgium); Ballester, J. L., E-mail: tdiaz@iac.es, E-mail: roberto.soler@wis.kuleuven.be, E-mail: dfsjlb0@uib.es [Departament de Fisica, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain)

2012-07-20T23:59:59.000Z

260

Designed Diamond Ground State via Optimized Isotropic Monotonic Pair Potentials  

E-Print Network (OSTI)

We apply inverse statistical-mechanical methods to find a simple family of optimized isotropic, monotonic pair potentials, under certain constraints, whose ground states for a wide range of pressures is the diamond crystal. These constraints include desirable phonon spectra and the widest possible pressure range for stability. We also ascertain the ground-state phase diagram for a specific optimized potential to show that other crystal structures arise for other pressures. Cooling disordered configurations interacting with our optimized potential to absolute zero frequently leads to the desired diamond crystal ground state, revealing that the capture basin for the global energy minimum is large and broad relative to the local energy minima basins.

Etienne Marcotte; Frank H. Stillinger; Salvatore Torquato

2012-12-15T23:59:59.000Z

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


261

Wave localization and density bunching in pair ion plasmas  

SciTech Connect

By investigating the nonlinear propagation of high intensity electromagnetic (EM) waves in a pair ion plasma, whose symmetry is broken via contamination by a small fraction of high mass immobile ions, it is shown that this new and interesting state of (laboratory created) matter is capable of supporting structures that strongly localize and bunch the EM radiation with density excess in the region of localization. Testing of this prediction in controlled laboratory experiments can lend credence, inter alia, to conjectures on structure formation (via the same mechanism) in the MEV era of the early universe.

Mahajan, Swadesh M. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States); Shatashvili, Nana L. [Faculty of Exact and Natural Sciences, Javakhishvili Tbilisi State University, Tbilisi 0128 (Georgia) and Andronikashvili Institute of Physics, Tbilisi 0177, Georgia (United States)

2008-10-15T23:59:59.000Z

262

Asymmetry-driven structure formation in pair plasmas  

SciTech Connect

The nonlinear propagation of electromagnetic waves in pair plasmas, in which the electrostatic potential plays a very important but subdominant role of a 'binding glue' is investigated. Several mechanisms for structure formation are investigated, in particular, the 'asymmetry' in the initial temperatures of the constituent species. It is shown that the temperature asymmetry leads to a (localizing) nonlinearity that is qualitatively different from the ones originating in ambient mass or density difference. The temperature-asymmetry-driven focusing-defocusing nonlinearity supports stable localized wave structures in 1-3 dimensions, which, for certain parameters, may have flat-top shapes.

Mahajan, S. M.; Shatashvili, N. L.; Berezhiani, V. I. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States); Andronikashvili Institute of Physics, Tbilisi 0177 (Georgia) and Faculty of Exact and Natural Sciences, Department of Physics, Javakhishvili Tbilisi State University, Tbilisi 0128 (Georgia)

2009-12-15T23:59:59.000Z

263

A canonical form for Projected Entangled Pair States and applications  

E-Print Network (OSTI)

We show that two different tensors defining the same translational invariant injective Projected Entangled Pair State (PEPS) in a square lattice must be the same up to a trivial gauge freedom. This allows us to characterize the existence of any local or spatial symmetry in the state. As an application of these results we prove that a SU(2) invariant PEPS with half-integer spin cannot be injective, which can be seen as a Lieb-Shultz-Mattis theorem in this context. We also give the natural generalization for U(1) symmetry in the spirit of Oshikawa-Yamanaka-Affleck, and show that a PEPS with Wilson loops cannot be injective.

Perez-Garcia, D; Gonzalez-Guillen, C E; Wolf, M M; Cirac, J I

2009-01-01T23:59:59.000Z

264

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

E-Print Network (OSTI)

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

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

2001-01-01T23:59:59.000Z

265

HOM Survey of the First CEBAF Upgrade Style Cavity Pair  

SciTech Connect

The planned upgrade of the Continuous Electron Beam Accelerator Facility (CEBAF) at the Thomas Jefferson National Accelerator Laboratory (JLab) requires ten new superconducting rf (SRF) cavity cryomodules to double the beam energy to the envisaged 12 GeV. Adequate cavity Higher Order Mode (HOM) suppression is essential to avoid multipass, multibunch beam break-up (BBU) instabilities of the recirculating beam. We report on detailed HOM surveys performed for the first two upgrade style cavities tested in a dedicated cavity pair cryomodule at 2K. The safety margin to the BBU threshold budget at 12 GeV has been assessed.

Marhauser, Frank; Davis, G; Drury, Michael; Grenoble, Christiana; Hogan, John; Manus, Robert; Preble, Joseph; Reece, Charles; Rimmer, Robert; Tian, Kai

2009-05-01T23:59:59.000Z

266

Evaluation of Incompatibility Between an Electronic Air Ionizer and Digital Clock  

Science Conference Proceedings (OSTI)

This power quality (PQ) case study evaluates the incompatibility between an electronic air ionizer and a digital clock.

2003-12-31T23:59:59.000Z

267

Residual ionization in the expansion of a laser-produced plasma  

SciTech Connect

A condition is found for determining the stage of plasma expansion in vacuum at which ionization quenching occurs.

Busygin, A.I.

1977-11-01T23:59:59.000Z

268

Higgs boson pair production at the LHC in the $b \\bar{b} W^+ W^-$ channel  

E-Print Network (OSTI)

We consider Higgs boson pair production at the LHC in the $b \\bar{b} W^+ W^-$ channel, with subsequent decay of the $W^+W^-$ pair into $\\ell \

Papaefstathiou, Andreas; Zurita, José

2012-01-01T23:59:59.000Z

269

Connection between the Green functions of the supersymmetric pair of Dirac Hamiltonians  

E-Print Network (OSTI)

The Sukumar theorem about the connection between the Green functions of the supersymmetric pair of the Schr\\"odinger Hamiltonians is generalized to the case of the supersymmetric pair of the Dirac Hamiltonians.

Ekaterina Pozdeeva

2007-09-10T23:59:59.000Z

270

Computational phenotype prediction of ionizing-radiation-resistant bacteria with a multiple-instance learning model  

Science Conference Proceedings (OSTI)

Ionizing-radiation-resistant bacteria (IRRB) are important in biotechnology. The use of these bacteria for the treatment of radioactive wastes is determined by their surprising capacity of adaptation to radionuclides and a variety of toxic molecules. ... Keywords: ionizing-radiation-resistant bacteria, ionizing-radiation-sensitive bacteria, multiple-instance learning, phenotypic prediction, protein sequences

Sabeur Aridhi; Mondher Maddouri; Haitham Sghaier; Engelbert Mephu Nguifo

2013-08-01T23:59:59.000Z

271

Investigation of the nuetralino pair production at LHC  

E-Print Network (OSTI)

In this article, we investigate the Drell-Yan process of the light neutralino pair $\\widetilde{\\chi}_{i}^{0}\\widetilde{\\chi}_{j}^{0}$ ($i,j=1,2$) productions at proton-proton collisions and we present the general formulate for the differential cross sections. We conduct an extensive examination of the dependence of the total cross section of the subprocesses $q \\bar q \\to \\widetilde \\chi_{i}^{0}\\widetilde\\chi_{j}^{0}$ on the beam energy, on the mass of the squarks and also on the $M_2$ gaugino for the three extremely different scenarios. For all three cases, the outcomes are as follows. The dependence of the total cross section of the subprocesses $q \\bar q \\to \\widetilde \\chi_{i}^{0} \\widetilde \\chi_{j}^{0}$ on the beam energy is dominated by one of the subprocesses, $q \\bar q \\to \\widetilde \\chi_{1}^{0} \\widetilde \\chi_{2}^{0}$. On the other hand, the dependence of the total cross section of the subprocesses $q \\bar q \\to \\widetilde \\chi_{i}^{0} \\widetilde \\chi_{j}^{0}$ on the mass of the squarks is dominated by one of the subprocesses, $q \\bar q \\to \\widetilde \\chi_{1}^{0} \\widetilde \\chi_{2}^{0}$. We derive there from that our findings may lead to new insights relating to experimental investigations and these dependencies may be used as bases of an experimental research for the neutralino pair at LHC.

A. I. Ahmadov; I. Boztosun; R. Kh. Muradov; A. Soylu; E. A. Dadashov

2006-04-20T23:59:59.000Z

272

Photon polarisation in electron-seeded pair-creation cascades  

E-Print Network (OSTI)

An electromagnetic pair-creation cascade seeded by an electron or a photon in an intense plane wave interacts in a complicated way with the external field. Many simulations neglect the vector nature of photons by including their interaction using unpolarised cross-sections. After deriving rates for the tree-level processes of nonlinear Compton scattering and pair creation with an arbitrary linearly-polarised photon in a constant-crossed field, we present results of numerical simulations that include the photon's vector nature. The simulations of seed electrons in a rotating electric field of optical frequency on the one hand support the approximation of using unpolarised cross-sections for tree-level processes, which predicts the same number of created particles when using polarised cross-section to within around 5 percent. On the other hand, these simulations show that when the polarisation of the photon can be influenced by its environment, the asymmetry in the polarisation distribution could be used to significantly increase the rates of each process.

B. King; N. Elkina; H. Ruhl

2013-01-29T23:59:59.000Z

273

Charge insensitive qubit design derived from the Cooper pair box  

E-Print Network (OSTI)

Short dephasing times pose one of the main challenges in realizing a quantum computer. Different approaches have been devised to cure this problem for superconducting qubits, a prime example being the operation of such devices at optimal working points, so-called "sweet spots." This latter approach led to significant improvement of $T_2$ times in Cooper pair box qubits [D. Vion et al., Science 296, 886 (2002)]. Here, we introduce a new type of superconducting qubit called the "transmon." Unlike the charge qubit, the transmon is designed to operate in a regime of significantly increased ratio of Josephson energy and charging energy $E_J/E_C$. The transmon benefits from the fact that its charge dispersion decreases exponentially with $E_J/E_C$, while its loss in anharmonicity is described by a weak power law. As a result, we predict a drastic reduction in sensitivity to charge noise relative to the Cooper pair box and an increase in the qubit-photon coupling, while maintaining sufficient anharmonicity for selective qubit control. Our detailed analysis of the full system shows that this gain is not compromised by increased noise in other known channels.

Jens Koch; Terri M. Yu; Jay Gambetta; A. A. Houck; D. I. Schuster; J. Majer; Alexandre Blais; M. H. Devoret; S. M. Girvin; R. J. Schoelkopf

2007-02-28T23:59:59.000Z

274

Creation of Electron Spinless Pairs in the Superconductivity  

E-Print Network (OSTI)

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

V. N. Minasyan

2009-03-02T23:59:59.000Z

275

Role of BCS-type pairing in light deformed nuclei: A relativistic mean field approach  

E-Print Network (OSTI)

We calculate the binding energy and deformation parameter for light nuclei with and without pairing using a deformed relativistic mean field model. The role of BCS-type pairing effect is analyzed for Ne and F isotopes. The calculated odd-even staggering and the deformation parameters argue strongly against the role of pairing in the light nuclei.

P. Arumugam; T. K. Jha; S. K. Patra

2003-11-25T23:59:59.000Z

276

An incremental approach to closest pair queries in spatial networks using best-first search  

Science Conference Proceedings (OSTI)

This paper addresses the problem of k Closest Pairs (kCP) query in spatial network databases. A Best-First search approach namely BFCP (Best-First Closest Pair) is proposed. Given two data sets of objects in a spatial network, BFCP first finds the 1st ... Keywords: buffer management, closest pair, location-based services, spatial networks

Chunan Chen; Weiwei Sun; Baihua Zheng; Dingding Mao; Weimo Liu

2011-08-01T23:59:59.000Z

277

Field Ionization of Cold Atoms near the Wall of a Single Carbon Nanotube  

E-Print Network (OSTI)

We observe the capture and field ionization of individual atoms near the side wall of a single suspended nanotube. Extremely large cross sections for ionization from an atomic beam are observed at modest voltages due to the nanotube's small radius and extended length. The effects of the field strength on both the atomic capture and the ionization process are clearly distinguished in the data, as are prompt and delayed ionizations related to the locations at which they occur. Efficient and sensitive neutral atom detectors can be based on the nanotube capture and wall ionization processes.

Anne Goodsell; Trygve Ristroph; J. A. Golovchenko; Lene Vestergaard Hau

2010-04-15T23:59:59.000Z

278

Triple Differential Cross sections and Nuclear Recoil in Two-Photon Double Ionization of Helium  

SciTech Connect

Triple differential cross sections (TDCS) for two-photon double ionization of helium are calculated using the method of exterior complex scaling both above and below the threshold for sequential ionization (54.4 eV). It is found that sequential ionization produces characteristic behavior in the TDCS that identifies that process when it is in competition with nonsequential ionization. Moreover we see the signature in the TDCS and nuclear recoil cross sections of"virtual sequential ionization" below the threshold for the sequential process.

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

2008-04-29T23:59:59.000Z

279

Ionic Liquids and Ionizing Radiation: Reactivity of Highly Energetic  

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

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

280

Oxidative Stress and Skeletal Health with Low Dose, Ionizing Radiation  

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

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

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281

Low Dose Radiation Research Program: Research Highlights - Ionizing  

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

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

282

Low dose ionizing radiation induces tumor growth promoting factors in  

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

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

283

Pulsed extraction of ionization from helium buffer gas  

E-Print Network (OSTI)

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

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

2008-08-13T23:59:59.000Z

284

Rayleigh-Taylor Instability of Ionization Front around Black Holes  

E-Print Network (OSTI)

We examine the role of ionizing radiation emitted from black holes (BHs) in suppressing the growth of the Rayleigh-Taylor instability (RTI) across the ionization front (I-front) that forms when the gas fueling the BH is neutral. We use radiation-hydrodynamic simulations to show that the RTI is suppressed for non-accelerating fronts on all scales resolved in our simulations. A necessary condition for the stability of the I-front is that the radius of the Str\\"omgren sphere is larger than the Bondi radius. When this condition is violated the I-front collapses producing an accretion luminosity burst. Transient growth of the RTI occurs only during the accretion burst when the effective acceleration in the frame of reference of the I-front increases significantly due to the rapid expansion of the Str\\"omgren sphere.

Park, KwangHo; Di Matteo, Tiziana; Reynolds, Christopher S

2013-01-01T23:59:59.000Z

285

INTERACTION OF MUON BEAM WITH PLASMA DEVELOPED DURING IONIZATION COOLING  

Science Conference Proceedings (OSTI)

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.

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

2012-07-01T23:59:59.000Z

286

Resonance Ionization Mass Spectrometry System for Measurement of Environmental Samples  

Science Conference Proceedings (OSTI)

A resonance ionization mass spectrometry (RIMS) system has been developed at the National Institute of Standards and Technology (NIST) for sensitive and selective determination of radio?cesium in the environment. The overall efficiency was determined to be 4×10?7 with a combined (laser and mass spectrometer) selectivity of 108 for both 135Cs and 137Cs with respect to 133Cs. RIMS isotopic ratio measurements of 135Cs/ 137Cs were performed on a nuclear fuel burn?up sample and compared to measurements on a similar system at Pacific Northwest National Laboratory (PNNL) and to conventional thermal ionization mass spectrometry (TIMS). Results of preliminary RIMS investigations on a freshwater lake sediment sample are also discussed.

L. Pibida; C. A. McMahon; W. Nörtershäuser; B. A. Bushaw

2002-01-01T23:59:59.000Z

287

Study of the response of low pressure ionization chambers  

E-Print Network (OSTI)

The Beam Loss Monitoring System (BLM) of the Large Hadron Collider (LHC) is based on parallel plate Ionization Chambers (IC) with active volume 1.5l and a nitrogen filling gas at 0.1 bar overpressure. At the largest loss locations, the ICs generate signals large enough to saturate the read-out electronics. A reduction of the active volume and filling pressure in the ICs would decrease the amount of charge collected in the electrodes, and so provide a higher saturation limit using the same electronics. This makes Little Ionization Chambers (LIC) with both reduced pressure and small active volume a good candidate for these high radiation areas. In this contribution we present measurements performed with several LIC monitors with reduced active volume and various filling pressures. These detectors were tested under various conditions with different beam setups, with standard LHC ICs used for calibration purposes

Nebot Del Busto, E; Effinger, E; Grishin, V; Herranz Alvarez, J

2012-01-01T23:59:59.000Z

288

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

Science Conference Proceedings (OSTI)

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.

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. [Physics and Astronomy Department, University of Delaware, Newark, Delaware 19716 (United States)

2010-10-15T23:59:59.000Z

289

Optics for Phase Ionization Cooling of Muon Beams  

DOE Green Energy (OSTI)

The realization of a muon collider requires a reduction of the 6D normalized emittance of an initially generated muon beam by a factor of more than 106. Analytical and simulation studies of 6D muon beam ionization cooling in a helical channel filled with pressurized gas or liquid hydrogen absorber indicate that a factor of 106 is possible. Further reduction of the normalized 4D transverse emittance by an additional two orders of magnitude is envisioned using Parametric-resonance Ionization Cooling (PIC). To realize the phase shrinkage effect in the parametric resonance method, one needs to design a focusing channel free of chromatic and spherical aberrations. We report results of our study of a concept of an aberration-free wiggler transport line with an alternating dispersion function. Resonant beam focusing at thin beryllium wedge absorber plates positioned near zero dispersion points then provides the predicted PIC effect.

R.P. Johnson; S.A. Bogacz; Y.S. Derbenev

2006-06-26T23:59:59.000Z

290

Hugoniot Data for Helium in the Ionization Regime  

Science Conference Proceedings (OSTI)

Hugoniot data were obtained for fluid He in the 100 GPa pressure range by shock compression of samples statically precompressed in diamond-anvil cells. The initial (precompressed) He density ({rho}{sub 1}) for each experiment was tuned to a value between {rho}{sub 0L}=}3{rho}{sub 0L} (i.e., {rho}/{rho}{sub 0L}{>=}12). Data show an increase in compressibility at the onset of ionization, similar to theoretical predictions.

Eggert, J.; Celliers, P. M.; Hicks, D. G.; Collins, G. W. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Brygoo, S. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Departement de Physique, Theorique et Applications, CEA, Commissariat a l'Energie Atomique, 91680 Bruyeres-le-Chatel (France); Loubeyre, P. [Departement de Physique, Theorique et Applications, CEA, Commissariat a l'Energie Atomique, 91680 Bruyeres-le-Chatel (France); McWilliams, R. S. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); University of California, Berkeley, California (United States); Boehly, T. R. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York (United States); Jeanloz, R. [University of California, Berkeley, California (United States)

2008-03-28T23:59:59.000Z

291

Interference in above-threshold-ionization electron distributions from molecules  

SciTech Connect

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

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

2011-05-15T23:59:59.000Z

292

Effects of Ionization in a Laser Wakefield Accelerator  

Science Conference Proceedings (OSTI)

Experimental results are presented from studies of the ionization injection process in laser wakefield acceleration using the Hercules laser with laser power up to 100 TW. Gas jet targets consisting of gas mixtures reduced the density threshold required for electron injection and increased the maximum beam charge. Gas mixture targets produced smooth beams even at densities which would produce severe beam breakup in pure He targets and the divergence was found to increase with gas mixture pressure.

McGuffey, C.; Schumaker, W.; Matsuoka, T.; Dollar, F. J.; Chvykov, V.; Kalintchenko, G.; Yanovsky, V.; Thomas, A. G. R.; Maksimchuk, A.; Krushelnick, K. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, MI (United States); Kneip, S. [Imperial College London, SW 7 2AZ (United Kingdom); Bychenkov, V. Yu. [P. N. Lebedev Physics Institute, Leninskij prospekt, 53, Moscow (Russian Federation); Glazyrin, I. V.; Karpeev, A. V. [Russian Federal Nuclear Centre All-Russian Institute of Technical Physics, 456770, Snezhinsk, Chelyabinsk Region (Russian Federation)

2010-11-04T23:59:59.000Z

293

Electrostatic ion waves in non-Maxwellian pair-ion plasmas  

SciTech Connect

The electrostatic ion waves are studied for non-Maxwellian or Lorentzian distributed unmagnetized pair-ion plasmas. The Vlasov equation is solved and damping rates are calculated for electrostatic waves in Lorentzian pair-ion plasmas. The damping rates of the electrostatic ion waves are studied for the equal and different ion temperatures of pair-ion species. It is found that the Landau damping rate of the ion plasma wave is increased in Lorentzian plasmas in comparison with Maxwellian pair-ion plasmas. The numerical results are also presented for illustration by taking into account the parameters reported in fullerene pair-ion plasma experiments.

Arshad, Kashif [Department of Physics, Quaid-i-Azam University, Islamabad 44000 (Pakistan); National Centre for Physics, Quaid-i-Azam University Campus, Shadhra Valley Road, Islamabad 44000 (Pakistan); Mahmood, S. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan); National Centre for Physics, Quaid-i-Azam University Campus, Shadhra Valley Road, Islamabad 44000 (Pakistan)

2010-12-15T23:59:59.000Z

294

The ionization structure of early-B supergiant winds  

E-Print Network (OSTI)

We present empirically determined ionization conditions for the winds of 106 luminous B0 to B5 stars observed by IUE. The UV wind lines are modelled to extract products of mass-loss rates (Mdot) times ionization fractions (Mdot q_i(w), where w = v/v_infty) for N V, C IV, Si IV, Si III, Al III and C II. We describe the general behaviour of the Mdot q_i(w) and their ratios, demonstrating that the wind ionization increases with distance from the star, contrary to recent findings for O star winds. Using empirical mass-loss rates (from H alpha observations) and model prescriptions, we derive mean q_i(w) values integrated over the wind, . These are quite small, never exceeding 15% for Al III or 2% for Si IV. This is surprising, since the for these ions clearly peak within the observed spectral range. We conclude that the low arise because the are underestimated by the wind models, which assume that the outflows are smooth when they are, in fact, highly structured.

R. K. Prinja; D. Massa; S. C. Searle

2004-12-13T23:59:59.000Z

295

The effect of microhydration on ionization energies of thymine  

Science Conference Proceedings (OSTI)

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

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

2011-01-03T23:59:59.000Z

296

The effect of microhydration on ionization energies of thymine  

SciTech Connect

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

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

2011-01-03T23:59:59.000Z

297

High-resolution ionization detector and array of such detectors  

DOE Patents (OSTI)

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

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

2001-01-16T23:59:59.000Z

298

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

Science Conference Proceedings (OSTI)

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

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

2011-09-15T23:59:59.000Z

299

Reduction in maximum time uncertainty of paired time signals  

DOE Patents (OSTI)

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

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

1981-02-11T23:59:59.000Z

300

A pair distribution function analysis of zeolite beta  

SciTech Connect

We describe the structural refinement of zeolite beta using the local structure obtained with the pair distribution function (PDF) method. A high quality synchrotron and two neutron scattering datasets were obtained on two samples of siliceous zeolite beta. The two polytypes that make up zeolite beta have the same local structure; therefore refinement of the two structures was possible using the same experimental PDF. Optimized structures of polytypes A and B were used to refine the structures using the program PDFfit. Refinements using only the synchrotron or the neutron datasets gave results inconsistent with each other but a cyclic refinement with the two datasets gave a good fit to both PDFs. The results show that the PDF method is a viable technique to analyze the local structure of disordered zeolites. However, given the complexity of most zeolite frameworks, the use of both X-ray and neutron radiation and high-resolution patterns is essential to obtain reliable refinements.

Martinez-Inesta, M.M.; Peral, I.; Proffen, T.; Lobo, R.F. (Delaware); (LANL)

2010-07-20T23:59:59.000Z

Note: This page contains sample records for the topic "ionization brems pair" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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301

Photoproduction of {pi}{pi} Pairs off {sup 7}Li  

Science Conference Proceedings (OSTI)

This paper reports on the quasi-free photoproduction of {pi}{sup 0}{pi}{sup 0} and {pi}{sup 0}{pi}{sup +/-} pairs from {sup 7}Li in view of the in-medium properties of hadrons. Measurements have been done using the CB/TAPS detector setup and the Glasgow photon tagging spectrometer for incident photon energies up to 820 MeV. At small invariant masses, an enhancement of the neutral invariant mass distributions is seen compared to the mixed charged channel and could be explained either by an in-medium modification of the {pi}{pi} interaction in the I = J = 0 channel or by effects related to the final state interactions.

Maghrbi, Yasser [Department of Physics, University of Basel, CH-4056 Basel (Switzerland)

2011-10-21T23:59:59.000Z

302

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

Science Conference Proceedings (OSTI)

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

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

2012-05-14T23:59:59.000Z

303

Measurement of jet multiplicity in top pair events  

E-Print Network (OSTI)

The normalized differential $t\\bar t$ cross section in jet multiplicity bins is presented, measured in proton-proton collisions using 5.0~fb$^{-1}$ of data collected at $\\sqrt{s}$ = 7~\\TeV. The analysis is performed in the electron + jets and the muon + jets channels. The jet multiplicity distribution is sensitive to initial state radiation. A comparison of the data with different Monte Carlo generators is shown. After background subtraction, the data are in agreement with $t\\bar t$ signal Monte Carlo distributions. Additionally, the measurement of the top quark pair differential cross-section in the number of radiated additional hard partons in the muon + jets channel is presented. The measured fractions of events with $t\\bar t$ + 0, 1, and $\\geq$ 2 additional partons are in good agreement with different Monte Carlo predictions.

CMS Collaboration

2012-01-01T23:59:59.000Z

304

High energy ionization in liquids: The free ion yield  

SciTech Connect

This paper considers some recent experimental results (n-hexane, neopentane, 2,2,4,4-tetramethylpentane, 2,2,4-trimethylpentane) which show how G{sub fi}(number of ion pairs or free ions per 100 eV absorbed) depends on conditions. The results provide insight into factors which determine free ion yield: molecular structure, field, temperature, tracks, density.

Holroyd, R.

1993-09-01T23:59:59.000Z

305

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

SciTech Connect

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

OUYANG,S.; VAIRAVAMURTHY,M.A.

1999-06-13T23:59:59.000Z

306

Ionized gas and stellar kinematics of seventeen nearby spiral galaxies  

E-Print Network (OSTI)

Ionized gas and stellar kinematics have been measured along the major axes of seventeen nearby spiral galaxies of intermediate to late morphological type. We discuss the properties of each sample galaxy distinguishing between those characterized by regular or peculiar kinematics. In most of the observed galaxies ionized gas rotates more rapidly than stars and have a lower velocity dispersion, as is to be expected if the gas is confined in the disc and supported by rotation while the stars are mostly supported by dynamical pressure. In a few objects, gas and stars show almost the same rotational velocity and low velocity dispersion, suggesting that their motion is dominated by rotation. Incorporating the spiral galaxies studied by Bertola et al. (1996), Corsini et al. (1999, 2003) and Vega Beltran et al. (2001) we have compiled a sample of 50 S0/a-Scd galaxies, for which the major-axis kinematics of the ionized gas and stars have been obtained with the same spatial (~1'') and spectral (~50km/s) resolution, and measured with the same analysis techniques. This allowed us to address the frequency of counterrotation in spiral galaxies. It turns out that less than 12% and less than 8% (at the 95% confidence level) of the sample galaxies host a counterrotating gaseous and stellar disc, respectively. The comparison with S0 galaxies suggests that the retrograde acquisition of small amounts of external gas gives rise to counterrotating gaseous discs only in gas-poor S0s, while in gas-rich spirals the newly acquired gas is swept away by the pre-existing gas. Counterrotating gaseous and stellar discs in spirals are formed only from the retrograde acquisition of large amounts of gas exceeding that of pre-existing gas, and subsequent star formation, respectively.

A. Pizzella; E. M. Corsini; J. C. Vega-Beltran; F. Bertola

2004-04-28T23:59:59.000Z

307

Two-photon production of charged pion and kaon pairs  

E-Print Network (OSTI)

A measurement of the cross section for the combined two-photon production of charged pion and kaon pairs is performed using 1.2~\\rm fb^{-1} of data collected by the CLEO II detector at the Cornell Electron Storage Ring. The cross section is measured at invariant masses of the two-photon system between 1.5 and 5.0~GeV/c^2, and at scattering angles more than 53^\\circ away from the \\gamma\\gamma collision axis in the \\gamma\\gamma center-of-mass frame. The large background of leptonic events is suppressed by utilizing the CsI calorimeter in conjunction with the muon chamber system. The reported cross section is compared with leading order QCD models as well as previous experiments. In particular, although the functional dependence of the measured cross section disagrees with leading order QCD at small values of the two-photon invariant mass, the data show a transition to perturbative behavior at an invariant mass of approximately 2.5~GeV/c^2. hardcopies with figures can be obtained by writing to to: Pam Morehouse ...

Dominick, J; Sanghera, S; Shelkov, V; Skwarnicki, T; Stroynowski, R; Volobuev, I P; Wei, G; Zadorozhny, P; Artuso, M; Goldberg, M; He, D; Horwitz, N; Kennett, R; Mountain, R; Moneti, G C; Muheim, F; Mukhin, Y; Playfer, S; Rozen, Y; Stone, S; Thulasidas, M; Vasseur, G; Zhu, G; Bartelt, J; Csorna, S E; Egyed, Z; Jain, V; Kinoshita, K; Edwards, K W; Ogg, M; Britton, D I; Hyatt, E R F; MacFarlane, D B; Patel, P M; Akerib, D S; Barish, B C; Chadha, M; Chan, S; Cowen, D F; Eigen, G; Miller, J S; O'Grady, C; Urheim, J; Weinstein, A J; Acosta, D; Athanas, M; Masek, G E; Paar, H P; Sivertz, M; Gronberg, J B; Kutschke, R; Menary, S R; Morrison, R J; Nakanishi, S; Nelson, H N; Nelson, T K; Qiao, C; Richman, J D; Ryd, A; Tajima, H; Sperka, D; Witherell, M S; Procario, M; Balest, R; Cho, K; Daoudi, M; Ford, W T; Johnson, D R; Lingel, K; Lohner, M; Rankin, P; Smith, J G; Alexander, J P; Bebek, C; Berkelman, K; Bloom, K; Browder, T E; Cassel, David G; Cho, H A; Coffman, D M; Drell, P S; Ehrlich, R; Gaidarev, P B; Galik, R S; García-Sciveres, M; Geiser, B; Gittelman, B; Gray, S W; Hartill, D L; Heltsley, B K; Jones, C D; Jones, S L; Kandaswamy, J; Katayama, N; Kim, P C; Kreinick, D L; Ludwig, G S; Masui, J; Mevissen, J; Mistry, N B; Ng, C R; Nordberg, E; Patterson, J R; Peterson, D; Riley, D; Salman, S; Sapper, M; Würthwein, F; Avery, P; Freyberger, A P; Rodríguez, J; Stephens, R; Yang, S; Yelton, J; Cinabro, D; Henderson, S; Liu, T; Saulnier, M; Wilson, R; Yamamoto, H; Bergfeld, T; Eisenstein, B I; Gollin, G; Ong, B; Palmer, M; Selen, M; Thaler, J J; Sadoff, A J; Ammar, R; Ball, S; Baringer, P; Bean, A; Besson, D; Coppage, D; Copty, N K; Davis, R; Hancock, N; Kelly, M; Kwak, N; Lam, H; Kubota, Y; Lattery, M; Nelson, J K; Patton, S; Perticone, D; Poling, R A; Savinov, V; Schrenk, S; Wang, R; Alam, M S; Kim, I J; Nemati, B; O'Neill, J J; Severini, H; Sun, C R; Zoeller, M M; Crawford, G; Daubenmier, C M; Fulton, R; Fujino, D; Gan, K K; Honscheid, K; Kagan, H; Kass, R; Lee, J; Malchow, R L; Skovpen, Y; Sung, M; White, C; Butler, F; Fu, X; Kalbfleisch, G R; Ross, W R; Skubic, P L; Snow, J; Wang, P L; Wood, M; Brown, D N; Fast, J; McIlwain, R L; Miao, T; Miller, D H; Modesitt, M; Payne, D; Shibata, E I; Shipsey, I P J; Wang Pei Ning; Battle, M; Ernst, J; Kwon, Y; Roberts, S; Thorndike, E H; Wang, C H

1994-01-01T23:59:59.000Z

308

Modeling heavy ion ionization loss in the MARS15 code  

E-Print Network (OSTI)

The needs of various accelerator and space projects stimulated recent developments to the MARS Monte Carlo code. One of the essential parts of those is heavy ion ionization energy loss. This paper describes an implementation of several corrections to dE/dx in order to take into account the deviations from the Bethe theory at low and high energies as well as the effect of a finite nuclear size at ultra-relativistic energies. Special attention is paid to the transition energy region where the onset of the effect of a finite nuclear size is observed. Comparisons with experimental data and NIST data are presented.

I. L. Rakhno; N. V. Mokhov; S. I. Striganov

2005-05-05T23:59:59.000Z

309

The ionizing radiation environment in space and its effects  

Science Conference Proceedings (OSTI)

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

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

2012-11-20T23:59:59.000Z

310

Ionization potential for excited S states of the lithium atom  

Science Conference Proceedings (OSTI)

Nonrelativistic, relativistic, quantum electrodynamic, and finite nuclear mass corrections to the energy levels are obtained for the nS{sub 1/2},n=3,...,9 states of the lithium atom. Computational approach is based on the explicitly correlated Hylleraas functions with the analytic integration and recursion relations. Theoretical predictions for the ionization potential of nS{sub 1/2} states and transition energies nS{sub 1/2{yields}}2S{sub 1/2} are compared to known experimental values for {sup 6,7}Li isotopes.

Puchalski, M. [Faculty of Physics, University of Warsaw, Hoza 69, PL-00681 Warsaw (Poland); Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, PL-60780 Poznan (Poland); KePdziera, D. [Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 7, PL-87100 Torun (Poland); Pachucki, K. [Faculty of Physics, University of Warsaw, Hoza 69, PL-00681 Warsaw (Poland)

2010-12-15T23:59:59.000Z

311

Helical FOFO snake for 6D ionization cooling of muons  

DOE Green Energy (OSTI)

A channel for 6D ionization cooling of muons is described which consists of periodically inclined solenoids of alternating polarity, liquid hydrogen absorbers placed inside solenoids and RF cavities between them. Important feature of such channel (called Helical FOFO snake) is that it can cool simultaneously muons of both signs. Theoretical considerations as well as results of simulations with G4Beamline are presented which show that 200MHz HFOFO snake has sufficient acceptance to be used for initial 6D cooling in muon colliders and neutrino factories.

Alexahin, Y.; /Fermilab

2009-10-01T23:59:59.000Z

312

Atomic ionization of germanium due to neutrino magnetic moments  

E-Print Network (OSTI)

An ab initio calculation of atomic ionization of germanium (Ge) by neutrinos was carried out in the framework of multiconfiguration relativistic random phase approximation. The main goal is to provide a more accurate cross section formula than the conventional one, which is based on the free electron approximation, for searches of neutrino magnetic moments with Ge detectors whose threshold is reaching down to the sub-keV regime. Limits derived with both methods are compared, using reactor neutrino data taken with low threshold germanium detectors.

Jiunn-Wei Chen; Hsin-Chang Chi; Keh-Ning Huang; C. -P. Liu; Hao-Tse Shiao; Lakhwinder Singh; Henry T. Wong; Chih-Liang Wu; Chih-Pan Wu

2013-11-21T23:59:59.000Z

313

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

E-Print Network (OSTI)

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

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

2011-01-01T23:59:59.000Z

314

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

E-Print Network (OSTI)

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.

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

2009-08-13T23:59:59.000Z

315

COSMIC EVOLUTION OF STAR FORMATION ENHANCEMENT IN CLOSE MAJOR-MERGER GALAXY PAIRS SINCE z = 1  

Science Conference Proceedings (OSTI)

The infrared (IR) emission of 'M {sub *} galaxies' (10{sup 10.4} {star} {star formation enhancement induced by galaxy-galaxy interaction. Both the mean IR spectral energy distribution and mean IR luminosity of star-forming galaxies (SFGs) in SFG+SFG (S+S) pairs in the redshift bin of 0.6 star formation enhancement. SFGs in S+S pairs in a lower redshift bin of 0.2 star formation enhancement. Together with the significant and strong sSFR enhancement shown by SFGs in a local sample of S+S pairs (obtained using previously published Spitzer observations), our results reveal a trend for the star formation enhancement in S+S pairs to decrease with increasing redshift. Between z = 0 and z = 1, this decline of interaction-induced star formation enhancement occurs in parallel with the dramatic increase (by a factor of {approx}10) of the sSFR of single SFGs, both of which can be explained by the higher gas fraction in higher-z disks. SFGs in mixed pairs (S+E pairs) do not show any significant star formation enhancement at any redshift. The difference between SFGs in S+S pairs and in S+E pairs suggests a modulation of the sSFR by the intergalactic medium (IGM) in the dark matter halos hosting these pairs.

Xu, C. K.; Shupe, D. L.; Bock, J.; Bridge, C.; Cooray, A.; Lu, N.; Schulz, B. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Bethermin, M.; Aussel, H.; Elbaz, D.; Le Floc'h, E.; Riguccini, L. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu, CNRS, Universite Paris Diderot, CE-Saclay, pt courrier 131, F-91191 Gif-sur-Yvette (France); Berta, S.; Lutz, D.; Magnelli, B. [Max-Planck-Institut fuer Extraterrestrische Physik (MPE), Postfach 1312, D-85741 Garching (Germany); Conley, A. [Center for Astrophysics and Space Astronomy 389-UCB, University of Colorado, Boulder, CO 80309 (United States); Franceschini, A. [Dipartimento di Astronomia, Universita di Padova, vicolo Osservatorio, 3, I-35122 Padova (Italy); Marsden, G. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Oliver, S. J. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Pozzi, F. [INAF-Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monte Porzio Catone (Italy); and others

2012-11-20T23:59:59.000Z

316

Emission of photon pairs at discontinuities of nonlinearity in spontaneous parametric down-conversion  

E-Print Network (OSTI)

In order to fulfil the continuity requirements for electric- and magnetic-field amplitudes at discontinuities of chi2 nonlinearity additional photon pairs have to be emitted in the area of discontinuity. Generalized two-photon spectral amplitudes can be used to describe properties of photon pairs generated in this process that we call surface spontaneous parametric down-conversion. The spectral structure of such photon pairs is similar to that derived for photon pairs generated in the volume. Surface and volume contributions to spontaneous down-conversion can be comparable as an example of nonlinear layered structures shows.

Jan Perina Jr; Antonin Luks; Ondrej Haderka

2009-10-02T23:59:59.000Z

317

Photonic crystal fibre source of photon pairs for quantum information processing  

E-Print Network (OSTI)

We demonstrate two key components for optical quantum information processing: a bright source of heralded single photons; and a bright source of entangled photon pairs. A pair of pump photons produces a correlated pair of photons at widely spaced wavelengths (583 nm and 900 nm), via a $\\chi^{(3)}$ four-wave mixing process. We demonstrate a non-classical interference between heralded photons from independent sources with a visibility of 95%, and an entangled photon pair source, with a fidelity of 89% with a Bell state.

Jeremie Fulconis; Olivier Alibart; Jeremy L. O'Brien; William J. Wadsworth; John G. Rarity

2006-11-22T23:59:59.000Z

318

Natural orbits of atomic Cooper pairs in a nonuniform Fermi gas  

E-Print Network (OSTI)

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

Y. H. Pong; C. K. Law

2006-05-08T23:59:59.000Z

319

Cherenkov Radiation from e+e- Pairs and Its Effect on nu e Induced Showers  

E-Print Network (OSTI)

5] J. V. Jelley, Cherenkov Radiation and its applications (calculated the Cherenkov radiation from e + e ? pairs as a? 2 [1?? 2 ?(?)]), the radiation is suppressed compared to

Mandal, Sourav K.; Klein, Spencer R.; Jackson, J. David

2005-01-01T23:59:59.000Z

320

The observed ionization rate of the intergalactic medium and the ionizing emissivity at z >5: Evidence for a photon starved and extended epoch of reionization  

E-Print Network (OSTI)

We use a large set of hydrodynamical simulations, combined with measurements of the Lyman alpha opacity of the IGM taken from the literature, to obtain robust estimates for the photoionization rate per hydrogen atom at z=5 and 6. We find the photoionization rate drops by a factor of two and four, respectively, compared to our recent measurements at z = 2 - 4. The number of ionizing photons emitted by known sources at z=5 and 6, based on an extrapolation of source numbers below the detection limit and standard assumptions for the relationship between the ionizing emissivity and observed luminosity density at 1500 Angstroms, are in reasonable agreement with the photoionization rates inferred from the Lyman alpha forest if the escape fraction of ionizing photons from galaxies is large (>= 20 per cent). Claims to the contrary may be attributed to the adoption of an unduly high value for the clumping factor of ionized hydrogen. Using physically motivated assumptions for the mean free path of ionizing photons our measurements of the photoionization rate can be turned into an estimate of the ionizing emissivity. In comoving units the inferred ionizing emissivity is nearly constant over the redshift range 2-6 and corresponds to 1.5-3 photons emitted per hydrogen atom over a time interval corresponding to the age of the Universe at z=6. This strongly suggests that the epoch of reionization was photon-starved and extended. [Abridged

James S. Bolton; Martin G. Haehnelt

2007-03-13T23:59:59.000Z

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


321

Investigation of non-targeted effects of low dose ionizing radiation...  

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

Investigation of non-targeted effects of low dose ionizing radiation on the mammary gland utilizing three-dimensional culture models of mammary cells derived from mouse strains...

322

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

DOE Patents (OSTI)

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

Vertes, Akos; Nemes, Peter

2013-07-16T23:59:59.000Z

323

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

DOE Patents (OSTI)

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

Vertes, Akos; Nemes, Peter

2013-07-16T23:59:59.000Z

324

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

DOE Patents (OSTI)

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

Vertes, Akos; Nemes, Peter

2012-10-30T23:59:59.000Z

325

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

SciTech Connect

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

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

2011-11-29T23:59:59.000Z

326

Role of ATM kinase in ionizing radiation induced DNA damage response...  

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

ATM kinase in ionizing radiation induced DNA damage response in human neural stemprogenitor cells and differentiated cell types Adayabalam Balajee Columbia University Medical...

327

Using Co-Regulation to Understand Low-Dose Ionizing Radiation...  

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

with low and high doses of ionizing radiation (IR). Pathway analysis suggested that chromatin structure, as well as transcription control, plays a large role in linking gene...

328

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

Science Conference Proceedings (OSTI)

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

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

2010-06-15T23:59:59.000Z

329

Asymptotically-Equal-To 10 eV ionization shift in Ir K{alpha}{sub 2} from a near-coincident Lu K-edge  

SciTech Connect

Close to an x-ray filter's K-edge the transmission depends strongly on the photon energy. For a few atom pairs, the K-edge of one is only a few tens of eV higher than a K-line energy of another, so that a small change in the line's energy becomes a measurable change in intensity behind such a matching filter. Lutetium's K-edge is Asymptotically-Equal-To 27 eV above iridium's K{alpha}{sub 2} line, Asymptotically-Equal-To 63.287 keV for cold Ir. A Lu filter reduces this line's intensity by Asymptotically-Equal-To 10 % when it is emitted by a plasma, indicating an ionization shift {Delta}E Asymptotically-Equal-To 10{+-}1 eV.

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

2012-10-15T23:59:59.000Z

330

Study of Higgs Boson Pair Production at Linear Collider  

E-Print Network (OSTI)

We study the potential of the TESLA linear collider operated at a center-of-mass energy of 500 to 1000 GeV 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 b-quark and tau-lepton pairs is considered. An integrated luminosity of 500 fb^{-1} is assumed at each energy. The Higgs boson masses and production cross sections are measured by reconstructing the bbbb and bb\\tau\\tau final states. The precision of these measurements is evaluated in dependence of the Higgs boson masses. Under the assumed experimental conditions a statistical accuracy ranging from 0.1 to 1.0 GeV is achievable on the Higgs boson mass. The topological cross section \\sigma(e+e- -> HA -> bbbb) can be determined with the relative precision of 1.5 - 6.6 % and cross sections \\sigma(e+e- -> HA -> bb \\tau\\tau) and \\sigma(e+e- -> HA -> \\tau\\tau bb) with precision of 4 - 30 %. Constraints on the Higgs boson widths can be set exploiting bb\\tau\\tau channel. The 5\\sigma discovery limit corresponds to the Higgs mass of around 385 GeV for the degenerate Higgs boson masses in the HA -> bbbb channel at \\sqrts = 800 GeV with integrated luminosity of 500 fb^{-1}. The potential of the Higgs mass determination for the benchmark point SPS 1a for the process e+e- -> HA -> bbbb at \\sqrt{s} = 1 TeV and luminosity 1000 fb^{-1} is investigated.

K. Desch; T. Klimkovich; T. Kuhl; A. Raspereza

2004-06-21T23:59:59.000Z

331

Integrated Photon Pair Sources, Quantum Memories, and Lasers in Lithium Niobate  

E-Print Network (OSTI)

Integrated Photon Pair Sources, Quantum Memories, and Lasers in Lithium Niobate W. Sohler1 , H developments in the field of integrated quantum optics [1] exploiting lithium niobate (LN) waveguide technology: single photon pair sources with Ti:PPLN (periodically poled lithium niobate) waveguide, quantum memories

332

Precoding by Pairing Subchannels to Increase MIMO Capacity With Discrete Input Alphabets  

E-Print Network (OSTI)

Abstract—We consider Gaussian multiple-input multiple-output (MIMO) channels with discrete input alphabets. We propose a nondiagonal precoder based on the X-Codes in [1] to increase the mutual information. The MIMO channel is transformed into a set of parallel subchannels using singular value decomposition (SVD) and X-Codes are then used to pair the subchannels. X-Codes are fully characterized by the pairings and a 2 2 2 real rotation matrix for each pair (parameterized with a single angle). This precoding structure enables us to express the total mutual information as a sum of the mutual information of all the pairs. The problem of finding the optimal precoder with the above structure, which maximizes the total mutual information, is solved by: i) optimizing the rotation angle and the power allocation within each pair and ii) finding the optimal pairing and power allocation among the pairs. It is shown that the mutual information achieved with the proposed pairing scheme is very close to that achieved with the optimal precoder by Cruz et al., and is significantly better than Mercury/waterfilling strategy by Lozano et al. Our approach greatly simplifies both the precoder optimization and the detection complexity, making it suitable for practical applications. Index Terms—Condition number, multiple-input multiple-output (MIMO), mutual information, orthogonal frequency division multiplexing (OFDM), precoding, singular value decomposition (SVD). I.

Saif Khan Mohammed; Emanuele Viterbo; Yi Hong; Senior Member; Ananthanarayanan Chockalingam; Senior Member

2010-01-01T23:59:59.000Z

333

Pairing and alpha-like quartet condensation in N=Z nuclei  

E-Print Network (OSTI)

We discuss the treatment of isovector pairing by an alpha-like quartet condensate which conserves exactly the particle number, the spin and the isospin. The results show that the quartet condensate describes accurately the isovector pairing correlations in the ground state of systems with an equal number of protons and neutrons

N. Sandulescu; J. Dukelsky; D. Negrea

2011-07-21T23:59:59.000Z

334

Induction logging device with a pair of mutually perpendicular bucking coils  

SciTech Connect

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.

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

1981-01-01T23:59:59.000Z

335

MODULI SPACES OF PARABOLIC HIGGS BUNDLES AND PARABOLIC K(D) PAIRS OVER SMOOTH CURVES: I  

E-Print Network (OSTI)

MODULI SPACES OF PARABOLIC HIGGS BUNDLES AND PARABOLIC K(D) PAIRS OVER SMOOTH CURVES: I HANS U. BODEN AND K â?? OJI YOKOGAWA Abstract. This paper concerns the moduli spaces of rank two parabolic Higgs bundles and parabolic K(D) pairs over a smooth curve. Precisely which parabolic bundles occur in stable K

Boden, Hans U.

336

An Improved Test Case Generation Method of Pair-Wise Testing  

Science Conference Proceedings (OSTI)

Pair-wise testing is a testing criterion based on specification, which requires that for each pair of parameters, every combination of their valid value should be covered by at least one test case in the test set. This paper presents an improved method ...

Qian Feng-an; Jiang Jian-hui

2007-10-01T23:59:59.000Z

337

Nonperturbative enhancement of heavy quark-pair production in a strong SU(2) color field  

Science Conference Proceedings (OSTI)

Nonperturbative charm and bottom quark-pair production is investigated in the early stage of heavy-ion collisions. The time-dependent study is based on a kinetic description of fermion-pair production in strong non-Abelian fields. We introduce a time-dependent chromo-electric external field with a pulselike time evolution to simulate the overlap of two colliding heavy ions. The calculations is performed in a SU(2) color model with finite current quark masses. Yields of heavy quark pairs are compared to the ones of light and strange quark pairs. We show that the small inverse duration time of the field pulse determines the efficiency of the quark-pair production. The expected suppression for heavy quark production, as follows from the Schwinger formula for a constant field, is not seen, but rather an enhanced heavy quark production appears at ultrarelativistic energies.

Levai, Peter; Skokov, Vladimir [KFKI RMKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, Budapest 1525 (Hungary); Gesellschaft fuer Schwerionenforschung mbH, Planckstr. 1, D-64291 Darmstadt (Germany)

2010-10-01T23:59:59.000Z

338

Low-lying states of heavy nuclei within the nucleon pair approximation  

Science Conference Proceedings (OSTI)

In this article we perform systematic calculations on low-lying states of 33 nuclei with A=202-212, using the nucleon pair approximation of the shell model. We use a phenomenological shell-model Hamiltonian that includes single-particle energies, monopole and quadrupole pairing interactions, and quadrupole-quadrupole interactions. The building blocks of our model space include one J=4 valence neutron pair, and one J=4,6,8 valence proton pair, in addition to the usual S and D pairs. We calculate binding energies, excitation energies, electric quadrupole and magnetic dipole moments of low-lying states, and E2 transition rates between low-lying states. Our calculated results are reasonably consistent with available experimental data. The calculated quadrupole moments and magnetic moments, many of which have not yet been measured for these nuclei, are useful for future experimental measurements.

Xu, Z. Y.; Lei, Y. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhao, Y. M. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China); CCAST, World Laboratory, P.O. Box 8730, Beijing 100080 (China); Xu, S. W.; Xie, Y. X. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Arima, A. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Science Museum, Japan Science Foundation, 2-1 Kitanomaru-koen, Chiyoda-ku, Tokyo 102-0091 (Japan)

2009-05-15T23:59:59.000Z

339

Table  

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

E GeV b brems b pair b nucl b tot 2. 0.2843 0.1249 0.4706 0.8798 5. 0.3858 0.3088 0.4982 1.1927 10. 0.4697 0.4666 0.4832 1.4195 20. 0.5582 0.6382 0.4608 1.6572 50. 0.6786...

340

Table  

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

fluoride (LiF) ZA 0.46262 E GeV b brems b pair b nucl b tot 2. 0.2703 0.1209 0.4631 0.8543 5. 0.3668 0.2972 0.4895 1.1536 10. 0.4464 0.4463 0.4751 1.3679 20. 0.5299 0.6083...

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


341

Table  

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

fluoride (CaF 2 ) ZA 0.49670 E GeV b brems b pair b nucl b tot 2. 0.5234 0.2436 0.4381 1.2051 5. 0.7116 0.5985 0.4659 1.7760 10. 0.8649 0.8837 0.4539 2.2026 20. 1.0236 1.1853...

342

Table  

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

fluoride (BaF 2 ) ZA 0.42207 E GeV b brems b pair b nucl b tot 2. 1.1904 0.4473 0.3939 2.0317 5. 1.6414 1.3428 0.4200 3.4042 10. 2.0088 2.0396 0.4108 4.4591 20. 2.3862 2.7132...

343

Table  

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

fluoride CH 2 CHF 2 n ZA 0.49973 E GeV b brems b pair b nucl b tot 2. 0.2888 0.1285 0.4625 0.8800 5. 0.3917 0.3160 0.4897 1.1974 10. 0.4765 0.4748 0.4755 1.4269 20. 0.5656...

344

Table  

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

fluoride MgF 2 ZA 0.48153 E GeV b brems b pair b nucl b tot 2. 0.3729 0.1703 0.4493 0.9925 5. 0.5058 0.4161 0.4767 1.3985 10. 0.6144 0.6183 0.4638 1.6966 20. 0.7276 0.8364...

345

Table  

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

fluoride (CsF) ZA 0.42132 E GeV b brems b pair b nucl b tot 2. 1.2915 0.4882 0.3881 2.1679 5. 1.7810 1.4610 0.4141 3.6561 10. 2.1794 2.2166 0.4053 4.8014 20. 2.5885 2.9458...

346

Table  

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

Methane (CH 4 ) ZA 0.62334 E GeV b brems b pair b nucl b tot 2. 0.2088 0.0873 0.4904 0.7865 5. 0.2841 0.2205 0.5178 1.0224 10. 0.3477 0.3424 0.5009 1.1909 20. 0.4158 0.4754...

347

Table  

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

Ethanol (C 2 H 5 OH) ZA 0.56437 E GeV b brems b pair b nucl b tot 2. 0.2493 0.1077 0.4770 0.8341 5. 0.3385 0.2678 0.5044 1.1107 10. 0.4126 0.4080 0.4888 1.3095 20. 0.4912...

348

Table  

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

Air (dry, 1 atm) ZA 0.49919 E GeV b brems b pair b nucl b tot 2. 0.2898 0.1282 0.4628 0.8808 5. 0.3927 0.3151 0.4901 1.1979 10. 0.4774 0.4735 0.4758 1.4267 20. 0.5663 0.6460...

349

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

SciTech Connect

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

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

2012-11-20T23:59:59.000Z

350

Hydrocarbon rate coefficients for proton and electron impact ionization, dissociation, and recombination in a hydrogen plasma.  

DOE Green Energy (OSTI)

We estimate cross sections and rate coefficients for proton and electron impact ionization, dissociation, and recombination of neutral and ionized hydrocarbon molecules and fragments of the form C{sub x}H{sub y}{sup k}, x = 1-3, y = 1-6, k = 0,1 in a thermalized hydrogen-electron plasma.

Alman, D.A.; Brooks, J.N.; Ruzic, D.N.; Wang, Z.

1999-07-21T23:59:59.000Z

351

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

E-Print Network (OSTI)

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

Dunham, Scott

352

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

E-Print Network (OSTI)

, and area monitors to characterize the general background radiation environment harmful to humansDevelopment of Pattern Recognition Software for Tracks of Ionizing Radiation In Medipix2-Based tool for the automated identification and classification of tracks of ionizing radiation as measured

Vilalta, Ricardo

353

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

DOE Patents (OSTI)

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

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

1999-06-29T23:59:59.000Z

354

Multidimensional high harmonic spectroscopy: A semi-classical perspective on measuring multielectron rearrangement upon ionization  

E-Print Network (OSTI)

High harmonic spectroscopy has the potential to combine attosecond temporal with sub-Angstrom spatial resolution of the early nuclear and multielectron dynamics in molecules. It involves strong field ionization of the molecule by the IR laser field followed by time-delayed recombination of the removed electron with the molecular ion. The time-delay is controlled on the attosecond time scale by the oscillation of the IR field and is mapped into the harmonic number, providing a movie of molecular dynamics between ionization and recombination. One of the challenges in the analysis of high harmonic signal stems from the fact that the complex dynamics of both ionization and recombination with their multiple observables are entangled in the harmonic signal. Disentangling this information requires multidimensional approach, capable of mapping ionization and recombination dynamics into different independent parameters. We suggest multidimensional high harmonic spectroscopy as a tool for characterizing of ionization and recombination processes separately allowing for simultaneous detection of both the ionization delays and sub-cycle ionization rates. Our method extends the capability of the two dimensional (2D) set-up suggested recently by Shafir et al on reconstructing ionization delays, while keeping the reconstruction procedure as simple as in the original proposal. The scheme is based on the optimization of the high harmonic signal in orthogonally polarized strong fundamental and relatively weak multicolour control fields.

Valeria Serbinenko; Olga Smirnova

2013-05-12T23:59:59.000Z

355

Low Dose Ionizing Radiation Modulates Immune Function New Project Overview  

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

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

356

Recombining WMAP: constraints on ionizing and resonance radiation at recombination  

E-Print Network (OSTI)

We place new constraints on sources of ionizing and resonance radiation at the epoch of the recombination process using the recent CMB temperature and polarization spectra coming from WMAP. We find that non-standard recombination scenarios are still consistent with the current data. In light of this we study the impact that such models can have on the determination of several cosmological parameters. In particular, the constraints on curvature and baryon density appear to be weakly affected by a modified recombination scheme. However, it may affect the current WMAP constraints on inflationary parameters like the spectral index and its running. Physically motivated models, like those based on primordial black hole or super heavy dark matter decay, are able to provide a good fit to the current data. Future observations in both temperature and polarization will be needed to more stringently test these models.

Rachel Bean; Alessandro Melchiorri; Joe Silk

2003-06-18T23:59:59.000Z

357

Ionization detector, electrode configuration and single polarity charge detection method  

DOE Patents (OSTI)

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

He, Zhong (Ann Arbor, MI)

1998-01-01T23:59:59.000Z

358

Ionization detector, electrode configuration and single polarity charge detection method  

DOE Patents (OSTI)

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

He, Z.

1998-07-07T23:59:59.000Z

359

Non-Equilibrium Ionization States of GRB Environments  

E-Print Network (OSTI)

Iron spectral features are thought to be the best tracer of a progenitor of gamma-ray bursts (GRBs). The detections of spectral features such as an iron line and/or a Radiative Recombination edge and Continuum (RRC) were reported in four X-ray afterglows of GRBs. However their properties were different each other burst by burst. For example, Chandra observation of GRB 991216 reported both the strong H-like iron line together with its RRC. On the contrary, Yoshida et al. (2001) report only a detection of the strong RRC in GRB 970828 with ASCA. Since it is difficult to produce the strong RRC, we have to consider special condition for the line and/or the RRC forming region. In this paper, we point out a possibility of a ``non-equilibrium ionization state'' for the line and the RRC forming region.

Yonetoku, D; Masai, K; Yoshida, A; Kawai, N; Namiki, M

2001-01-01T23:59:59.000Z

360

Non-Equilibrium Ionization States of GRB Environments  

E-Print Network (OSTI)

Iron spectral features are thought to be the best tracer of a progenitor of gamma-ray bursts (GRBs). The detections of spectral features such as an iron line and/or a Radiative Recombination edge and Continuum (RRC) were reported in four X-ray afterglows of GRBs. However their properties were different each other burst by burst. For example, Chandra observation of GRB 991216 reported both the strong H-like iron line together with its RRC. On the contrary, Yoshida et al. (2001) report only a detection of the strong RRC in GRB 970828 with ASCA. Since it is difficult to produce the strong RRC, we have to consider special condition for the line and/or the RRC forming region. In this paper, we point out a possibility of a ``non-equilibrium ionization state'' for the line and the RRC forming region.

D. Yonetoku; T. Murakami; K. Masai; A. Yoshida; N. Kawai; M. Namiki

2001-07-18T23:59:59.000Z

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


361

CORROSION PRODUCT TRANSPORT AND DEPOSITION UNDER IONIZING RADIATION  

DOE Green Energy (OSTI)

A study was made of corrosion product transport and deposition on Zircaloy-2 and AISI 304 stainless steel in the presence and absence of ionizing radiation. Three 100-hour irradiation tests, using 2-Mev electrons from a Van de Graaff accelerator, and four 100-hour nonradiation tests were performed in 6O0 deg F pressurized water. Data from the seven runs and an additional exploratory run are presented. In addition, complete experimental procedures and descriptions of the apparatus are included. Control of pH was obtained by using H and OH form ion exchange resias for pH 7 and Li and OH form ion exchange resins for pH 10. The major conclusion to be drawn from the present work is that the deposition on Zircaloy-2 at pH 10 and 600 deg F is higher than on AISI 304 stainless steel at the same conditions. (auth)

Thomas, C.C. Jr.; Lacock, H.W.; Cadoff, H.Y. ed.

1958-12-01T23:59:59.000Z

362

Multiplexed electronically programmable multimode ionization detector for chromatography  

DOE Patents (OSTI)

Method and apparatus for detecting and differentiating organic compounds based on their electron affinity. An electron capture detector cell (ECD) is operated in a plurality of multiplexed electronically programmable operating modes to alter the detector response during a single sampling cycle to acquire multiple simultaneous chromatograms corresponding to each of the different operating modes. The cell is held at a constant subatmospheric pressure while the electron collection bias voltage applied to the cell is modulated electronically to allow acquisition of multiple chromatograms for a single sample elution from a chromatograph representing three distinctly different response modes. A system is provided which automatically controls the programmed application of bias pulses at different intervals and/or amplitudes to switch the detector from an ionization mode to the electron capture mode and various degrees therebetween to provide an improved means of tuning an ECD for multimode detection and improved specificity. 6 figs.

Wise, M.B.; Buchanan, M.V.

1988-05-19T23:59:59.000Z

363

Simulations of laser propagation and ionization in l'OASIS experiments  

Science Conference Proceedings (OSTI)

We have conducted particle-in-cell simulations of laser pulse propagation through neutral He, including the effects of tunneling ionization, within the parameter regime of the l'OASIS experiments [1,2] at the Lawrence Berkeley National Laboratory (LBNL). The simulations show the theoretically predicted [3] blue shifting of the laser frequency at the leading edge of the pulse. The observed blue shifting is in good agreement with the experimental data. These results indicate that such computations can be used to accurately simulate a number of important effects related to tunneling ionization for laser-plasma accelerator concepts, such as steepening due to ionization-induced pump depletion, which can seed and enhance instabilities. Our simulations show self-modulation occurring earlier when tunneling ionization is included then for a pre-ionized plasma.

Dimitrov, D.A.; Bruhwiler, D.L.; Leemans, W.; Esarey, E.; Catravas, P.; Toth, C.; Shadwick, B.; Cary, J.R.; Giacone, R.

2002-06-30T23:59:59.000Z

364

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

Science Conference Proceedings (OSTI)

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

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

2010-10-19T23:59:59.000Z

365

Three-Dimensional Studies of the Warm Ionized Medium in the Milky Way using WHAM  

E-Print Network (OSTI)

The Wisconsin H-Alpha Mapper (WHAM) is a high throughput Fabry-Perot facility developed specifically to detect and explore the warm, ionized component of the interstellar medium at high spectral resolution. It began operating at Kitt Peak, Arizona in 1997 and has recently completed the WHAM Northern Sky Survey (WHAM-NSS), providing the first global view of the distribution and kinematics of the warm, diffuse H II in the Milky Way. This H-alpha survey reveals a complex spatial and kinematic structure in the warm ionized medium and provides a foundation for studies of the temperature and ionization state of the gas, the spectrum and strength of the ionizing radiation, and its relationship to other components of the interstellar medium and sources of ionization and heating within the Galactic disk and halo. More information about WHAM and the Survey can be found at http://www.astro.wisc.edu/wham/.

R. J. Reynolds; L. M. Haffner; G. J. Madsen

2002-01-23T23:59:59.000Z

366

Three-Dimensional Studies of the Warm Ionized Medium in the Milky Way using WHAM  

E-Print Network (OSTI)

The Wisconsin H-Alpha Mapper (WHAM) is a high throughput Fabry-Perot facility developed specifically to detect and explore the warm, ionized component of the interstellar medium at high spectral resolution. It began operating at Kitt Peak, Arizona in 1997 and has recently completed the WHAM Northern Sky Survey (WHAM-NSS), providing the first global view of the distribution and kinematics of the warm, diffuse H II in the Milky Way. This H-alpha survey reveals a complex spatial and kinematic structure in the warm ionized medium and provides a foundation for studies of the temperature and ionization state of the gas, the spectrum and strength of the ionizing radiation, and its relationship to other components of the interstellar medium and sources of ionization and heating within the Galactic disk and halo. More information about WHAM and the Survey can be found at http://www.astro.wisc.edu/wham/.

Reynolds, R J; Madsen, G J

2002-01-01T23:59:59.000Z

367

Pressure dependence of the relativistic rise in neon and highest attainable ionization sampling resolution in neon, argon, ethylene and propane  

E-Print Network (OSTI)

Pressure dependence of the relativistic rise in neon and highest attainable ionization sampling resolution in neon, argon, ethylene and propane

Lehraus, Ivan; Tejessy, W

1983-01-01T23:59:59.000Z

368

Two-photon interference of photon pairs created in photonic crystal fibers  

E-Print Network (OSTI)

We investigate a method to produce photon pairs by four-wave mixing in photonic crystal fibers (PCFs). By controlling the wavelength of the pump light, which determines the phase matching condition for four-wave mixing, we can obtain a broader spectrum of photon pairs than undesired Raman-scattered photons. We observe two-photon interference of photon pairs from a PCF with the help of an unbalanced Mach-Zehnder interferometer. Two-photon interference fringes with 83% visibility, which exceeds the classical limit of 50%, are obtained.

Toshihiro Nakanishi; Kazuo Sakemi; Hirokazu Kobayashi; Kazuhiko Sugiyama; Masao Kitano

2009-02-01T23:59:59.000Z

369

Almost optimal pairing strategy for Tic-Tac-Toe with numerous directions  

E-Print Network (OSTI)

We show that there is an $m=2n+o(n)$, such that, in the Maker-Breaker game played on $\\Z^d$ where Maker needs to put at least $m$ of his marks consecutively in one of $n$ given winning directions, Breaker can force a draw using a pairing strategy. This improves the result of Kruczek and Sundberg who showed that such a pairing strategy exits if $m\\ge 3n$. A simple argument shows that $m$ has to be at least $2n+1$ if Breaker is only allowed to use a pairing strategy, thus the main term of our bound is optimal.

Mukkamala, Padmini

2010-01-01T23:59:59.000Z

370

Distribution of Primes and of Interval Prime Pairs Based on $?$ Function  

E-Print Network (OSTI)

$\\Theta$ 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.

Yifang Fan; Zhiyu Li

2010-04-19T23:59:59.000Z

371

SURFACE LAYER ACCRETION IN CONVENTIONAL AND TRANSITIONAL DISKS DRIVEN BY FAR-ULTRAVIOLET IONIZATION  

Science Conference Proceedings (OSTI)

Whether protoplanetary disks accrete at observationally significant rates by the magnetorotational instability (MRI) depends on how well ionized they are. Disk surface layers ionized by stellar X-rays are susceptible to charge neutralization by small condensates, ranging from {approx}0.01 {mu}m sized grains to angstrom-sized polycyclic aromatic hydrocarbons (PAHs). Ion densities in X-ray-irradiated surfaces are so low that ambipolar diffusion weakens the MRI. Here we show that ionization by stellar far-ultraviolet (FUV) radiation enables full-blown MRI turbulence in disk surface layers. Far-UV ionization of atomic carbon and sulfur produces a plasma so dense that it is immune to ion recombination on grains and PAHs. The FUV-ionized layer, of thickness 0.01-0.1 g cm{sup -2}, behaves in the ideal magnetohydrodynamic limit and can accrete at observationally significant rates at radii {approx}> 1-10 AU. Surface layer accretion driven by FUV ionization can reproduce the trend of increasing accretion rate with increasing hole size seen in transitional disks. At radii {approx}<1-10 AU, FUV-ionized surface layers cannot sustain the accretion rates generated at larger distance, and unless turbulent mixing of plasma can thicken the MRI-active layer, an additional means of transport is needed. In the case of transitional disks, it could be provided by planets.

Perez-Becker, Daniel [Department of Physics, University of California, Berkeley, CA 94720 (United States); Chiang, Eugene [Departments of Astronomy and Earth and Planetary Science, University of California, Berkeley, CA 94720 (United States)

2011-07-01T23:59:59.000Z

372

Automatic Analysis of Stereoscopic Satellite Image Pairs for Determination of Cloud-Top Height and Structure  

Science Conference Proceedings (OSTI)

A massively parallel processor (MPP) computer has made it practical to do automatic stereo analysis of cloud-top heights from stereoscopic satellite image pairs. The automatic analysis is of equivalent quality to manual analysis while taking ...

A. F. Hasler; J. Strong; R. H. Woodward; H. Pierce

1991-03-01T23:59:59.000Z

373

The power of linkage analysis of a disease-related endophenotype using asymmetrically ascertained sib pairs  

Science Conference Proceedings (OSTI)

A linkage study of a qualitative disease endophenotype in a sample of sib pairs, consisting of one disease affected proband and one sibling is considered. The linkage statistic compares marker allele sharing with the proband in siblings with an abnormal ...

Heejong Sung; Fei Ji; Deborah L. Levy; Steven Matthysse; Nancy Role Mendell

2009-03-01T23:59:59.000Z

374

A versatile waveguide source of photon pairs for chip-scale ...  

Science Conference Proceedings (OSTI)

... SD Dyer, MJ Stevens, B. Baek, and SW Nam, “High-efficiency, ultra low-noise all-fiber photon-pair source,” Opt. Express 16, 9966-9977 (2008). 30. ...

2010-08-19T23:59:59.000Z

375

Which Is Better, an Ensemble of Positive–Negative Pairs or a Centered Spherical Simplex Ensemble?  

Science Conference Proceedings (OSTI)

New methods to center the initial ensemble perturbations on the analysis are introduced and compared with the commonly used centering method of positive–negative paired perturbations. In the new method, one linearly dependent perturbation is ...

Xuguang Wang; Craig H. Bishop; Simon J. Julier

2004-07-01T23:59:59.000Z

376

Composite pairing in a mixed-valent two-channel Anderson model  

E-Print Network (OSTI)

Using a two-channel Anderson model, we develop a theory of composite pairing in the 115 family of heavy fermion superconductors that incorporates the effects of f-electron valence fluctuations. Our calculations introduce ...

Nevidomskyy, Andriy H.

377

Applications of correlated photon pairs : sub-shot noise interferometry and entanglement  

E-Print Network (OSTI)

Using cesium atoms weakly coupled to a low-finesse cavity, we have generated photon pairs that are highly correlated in a non-classical way, as demonstrated by a large violation of the Cauchy-Schwartz inequality G = 760 ...

Loh, Huanqian

2006-01-01T23:59:59.000Z

378

Fermionic superfluids : from cold atoms to high density QCD : gapless (breached pair) superfluidity and kaon condensation  

E-Print Network (OSTI)

In this thesis, we explore aspects of fermionic superfluidity through a mean-field approximation. Our framework is extremely general, includes both pairing and Hartree-Fock contributions, and is derived rigorously from a ...

Forbes, Michael McNeil

2005-01-01T23:59:59.000Z

379

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

E-Print Network (OSTI)

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

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

2011-01-01T23:59:59.000Z

380

The Role of Nuclear Motion in the Photo-Double Ionization ofMolecular Hydrogen  

DOE Green Energy (OSTI)

We examine the origin of recently observed variations with internuclear distance (R) of the fully differential cross sections for double ionization of aligned H2 by absorption of a single photon. Using the results of fully converged numerical solutions of the Schroedinger equation, we show that these variations arise primarily from pronounced differences in the R-dependence of the parallel and perpendicular components of the ionization amplitude. We also predict that R-dependences should be readily observable in the asymmetry parameter for photo-double ionization, even in experimental measurements that are not differential in the energy sharings between ejected photo-electrons.

Horner, Daniel A.; Vanroose, Wim; Rescigno, Thomas N.; Martin,Fernando; McCurdy, C. William

2006-10-26T23:59:59.000Z

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


381

Generation of Ultrahigh-Velocity Ionizing Shocks with Petawatt-Class Laser Pulses  

Science Conference Proceedings (OSTI)

Ultrahigh-velocity shock waves (approx10 000 km/s or 0.03c) are generated by focusing a 350-TW laser pulse into low-density helium gas. The collisionless ultrahigh-Mach-number electrostatic shock propagates from the plasma into the surrounding gas, ionizing gas as it becomes collisional. The shock undergoes a corrugation instability due to propagation of the ionizing shock within the gas (the Dyakov-Kontorovich instability). This system may be relevant to the study of very high-Mach-number ionizing shocks in astrophysical situations.

Nilson, P. M.; Mangles, S. P. D.; Willingale, L.; Kaluza, M. C.; Thomas, A. G. R.; Najmudin, Z.; Evans, R. G.; Dangor, A. E.; Krushelnick, K. [Department of Physics, Imperial College, London SW7 2AZ United Kingdom (United Kingdom); Tatarakis, M.; Lancaster, K. L. [Technological Educational Institute of Crete, Romanou, 3-GR73133 Chania (Greece); Clarke, R. J. [CLF, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon., OX11 0QX United Kingdom (United Kingdom); Karsch, S. [Max-Planck Institut fuer Quantenoptik, Hans-Kopfermann-Strasse, D-85748, Garching (Germany); Schreiber, J. [Max-Planck Institut fuer Quantenoptik, Hans-Kopfermann-Strasse, D-85748, Garching (Germany); Ludwig-Maximilians-Universistaet Munchen, Am Coulombwall, D-85748, Garching (Germany)

2009-12-18T23:59:59.000Z

382

Ionization and charge transfer in high-energy ion-atom collisions  

DOE Green Energy (OSTI)

Electron capture and loss by fast highly charged ions in a gas target, and ionization of the target by passage of the fast projectile beam, are fundamental processes in atomic physics. These processes, along with excitation, can be experimentally studied separately (''singles'') or together (''coincidence''). This paper is a review of recent results on singles measurements for electron capture and loss and for target ionization, for velocities which are generally high relative to the active electron, including recent ionization measurements for a nearly relativistic projectile. 11 refs., 6 figs.

Schlachter, A.S.; Berkner, K.H.; Stearns, J.W.; Schmidt-Boecking, H.; Kelbch, S.; Ullrich, J.; Hagmann, S.; Richard, P.; Stockli, M.P.; Graham, W.G.

1986-11-01T23:59:59.000Z

383

Reaction operators for spin-selective chemical reactions of radical pairs  

E-Print Network (OSTI)

Spin-selective reactions of radical pairs have traditionally been modelled theoretically by adding phenomenological rate equations to the quantum mechanical equation of motion of the radical pair spin density matrix. More recently an alternative set of rate expressions, based on a quantum measurement approach, has been suggested. Here we show how these two reaction operators can be seen as limiting cases of a more general reaction scheme.

Jones, Jonathan A; Hore, Peter J

2011-01-01T23:59:59.000Z

384

Reaction operators for spin-selective chemical reactions of radical pairs  

E-Print Network (OSTI)

Spin-selective reactions of radical pairs have traditionally been modelled theoretically by adding phenomenological rate equations to the quantum mechanical equation of motion of the radical pair spin density matrix. More recently an alternative set of rate expressions, based on a quantum measurement approach, has been suggested. Here we show how these two reaction operators can be seen as limiting cases of a more general reaction scheme.

Jonathan A. Jones; Kiminori Maeda; Peter J. Hore

2011-03-30T23:59:59.000Z

385

Schwinger Pair Production in dS_2 and AdS_2  

E-Print Network (OSTI)

We study Schwinger pair production in scalar QED from a uniform electric field in dS_2 with scalar curvature R_{dS} = 2 H^2 and in AdS_2 with R_{AdS} = - 2 K^2. With suitable boundary conditions, we find that the pair-production rate is the same analytic function of the scalar curvature in both cases.

Sang Pyo Kim; Don N. Page

2008-03-18T23:59:59.000Z

386

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

E-Print Network (OSTI)

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

Kleinert, Hagen; Xue, She-Sheng

2008-01-01T23:59:59.000Z

387

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

E-Print Network (OSTI)

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

Hagen Kleinert; Remo Ruffini; She-Sheng Xue

2008-07-06T23:59:59.000Z

388

Symmetrization of the Coulomb pairing potential by electron-phonon interaction  

Science Conference Proceedings (OSTI)

It is shown that the Coulomb superconducting pairing in systems with the Fermi contour nesting can be described by a quasi-one-dimensional potential oscillating in real space. The supplement of this repulsive potential with an isotropic pairing attraction corresponding to the phonon superconductivity mechanism and including the effect of predominant forward scattering upon electron-phonon interaction leads to symmetrization of this potential and a considerable increase in the superconducting transition temperature.

Belyavsky, V. I., E-mail: vib45@mail.ru; Kapaev, V. V.; Kopaev, Yu. V.; Mikhailyan, D. I. [Russian Academy of Sciences, Lebedev Physics Institute (Russian Federation)

2012-08-15T23:59:59.000Z

389

Regularized perturbative series for the ionization potential of atomic ions  

E-Print Network (OSTI)

We study N-electron atoms with nuclear charge Z. It is well known that, in the cationic (Z > N) high-Z region, the atom behaves as a weakly interacting system. The anionic (Z < N) regime, on the other hand, is characterized by an instability threshold at $Z \\lesssim N-1$ below which the atom spontaneously emits an electron. We construct a regularized perturbative series (RPS) for the ionization potential of ions in an isoelectronic sequence that exactly reproduces both, the large Z and the Z near $Z_c$ limits. The large-Z expansion coefficients are analytically computed from perturbation theory, whereas the slope of the energy curve at Z=N-1 is computed from a kind of zero-range forces theory that uses as input the electron affinity and the covalent radius of the neutral atom with N-1 electrons. Relativistic effects at the level of first-order perturbation theory in the one-particle Hamiltonian are considered. Our RPS results are compared with numbers from the NIST database.

Gil, G

2013-01-01T23:59:59.000Z

390

Progress on muon parametric-resonance ionization cooling channel development  

SciTech Connect

Parametric-resonance Ionization Cooling (PIC) is intended as the final 6D cooling stage of a high-luminosity muon collider. To implement PIC, a continuous-field twin-helix magnetic channel was developed. A 6D cooling with stochastic effects off is demonstrated in a GEANT4/G4beamline model of a system where wedge-shaped Be absorbers are placed at the appropriate dispersion points in the twin-helix channel and are followed by short rf cavities. To proceed to cooling simulations with stochastics on, compensation of the beam aberrations from one absorber to another is required. Initial results on aberration compensation using a set of various-order continuous multipole fields are presented. As another avenue to mitigate the aberration effect, we optimize the cooling channel's period length. We observe a parasitic parametric resonance naturally occurring in the channel's horizontal plane due to the periodic beam energy modulation caused by the absorbers and rf. We discuss options for compensating this resonance and/or properly combining it with the induced half-integer parametric resonance needed for PIC.

V.S. Morozov, Ya.S. Derbenev, A. Afanasev, K.B. Beard, R.P. Johnson, B. Erdelyi, J.A. Maloney

2012-07-01T23:59:59.000Z

391

Analytical models for total dose ionization effects in MOS devices.  

DOE Green Energy (OSTI)

MOS devices are susceptible to damage by ionizing radiation due to charge buildup in gate, field and SOI buried oxides. Under positive bias holes created in the gate oxide will transport to the Si / SiO{sub 2} interface creating oxide-trapped charge. As a result of hole transport and trapping, hydrogen is liberated in the oxide which can create interface-trapped charge. The trapped charge will affect the threshold voltage and degrade the channel mobility. Neutralization of oxidetrapped charge by electron tunneling from the silicon and by thermal emission can take place over long periods of time. Neutralization of interface-trapped charge is not observed at room temperature. Analytical models are developed that account for the principal effects of total dose in MOS devices under different gate bias. The intent is to obtain closed-form solutions that can be used in circuit simulation. Expressions are derived for the aging effects of very low dose rate radiation over long time periods.

Campbell, Phillip Montgomery; Bogdan, Carolyn W.

2008-08-01T23:59:59.000Z

392

Regime for a Self-ionizing Raman Laser Amplifier  

DOE Green Energy (OSTI)

Backward Raman amplification and compression at high power might occur if a long pumping laser pulse is passed through a plasma to interact resonantly with a counter-propagating short seed pulse [V.M. Malkin, et al., Phys. Rev. Lett. 82 (1999) 4448-4451]. One critical issue, however, is that the pump may be unacceptably depleted due to spontaneous Raman backscatter from intrinsic fluctuations in the amplifying plasma medium prior to its useful interaction with the seed. Premature backscatter may be avoided, however, by employing a gaseous medium with pump intensities too low to ionize the medium, and using the intense seed to produce the plasma by rapid photoionization as it is being amplified [V.M. Malkin, et al., Phys. Plasmas (2001)]. In addition to allowing that only rather low power pumps be used, photoionization introduces a damping of the short pulse which must be overcome by the Raman growth rate for net amplification to occur. The parameter space of gas densities, laser wavelengths, and laser intensities is surveyed to identify favorable regimes for this effect. Output laser intensities of 10(superscript ''17'') W/cm(superscript ''2'') for 0.5 mm radiation are found to be feasible for such a scheme using a pump of 10(superscript ''13'') W/cm(superscript ''2'') and an initial seed of 5 x 10(superscript ''14'') W/cm(superscript ''2'') over an amplification length of 5.6 cm in hydrogen gas.

D.S. Clark; N.J. Fisch

2001-10-04T23:59:59.000Z

393

Neutron And Gamma Detector Using An Ionization Chamber With An Integrated  

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

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

394

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

E-Print Network (OSTI)

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

Davidson, Matthew Allen

2011-01-01T23:59:59.000Z

395

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

E-Print Network (OSTI)

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

Chen, Liang-Yu, 1979-

2007-01-01T23:59:59.000Z

396

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

E-Print Network (OSTI)

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 ...

Velasquez-Garcia, Luis Fernando

397

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

SciTech Connect

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

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

2005-09-15T23:59:59.000Z

398

A Chemical Ionization Mass Spectrometer for Ground-Based Measurements of Nitric Acid  

Science Conference Proceedings (OSTI)

A chemical ionization mass spectrometer (CIMS) instrument has been developed for high-precision measurements of gaseous nitric acid (HNO3) specifically under high- and variable-humidity conditions in the boundary layer. The instrument’s ...

Kazuyuki Kita; Yu Morino; Yutaka Kondo; Yuichi Komazaki; Nobuyuki Takegawa; Yuzo Miyazaki; Jun Hirokawa; Shigeru Tanaka; Thomas L. Thompson; Ru-Shan Gao; David W. Fahey

2006-08-01T23:59:59.000Z

399

Multiwavelength WHAM Observations of Extra-planar Warm Ionized Gas in the Galaxy  

E-Print Network (OSTI)

Abstract. We report on observations of several optical emission lines toward a variety of newly revealed faint, large-scale H?-emitting structures in the warm ionized medium (WIM) of the Galaxy. The lines include [N II] ?6583,

G. J. Madsen

2004-01-01T23:59:59.000Z

400

Regulation of Annexin A2 by Ionizing Radiation in Human Skin...  

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

Annexin A2 by Ionizing Radiation in Human Skin Equivalent Culture: Does A Nuclear Annexin A2-Protein Kinase C Epsilon Complex Contribute To Reduced Cancer Risks At Low Dose...

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


401

Regulation of Annexin A2 by Ionizing Radiation in Human Skin...  

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

of Annexin A2 by Ionizing Radiation in Human Skin Equivalent Culture: Does A Nuclear Annexin A2-Protein Kinase C Epsilon Complex Contribute To Reduced Cancer Risks At Low...

402

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

E-Print Network (OSTI)

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

S. Huang; C. Chandre; T. Uzer

2007-08-09T23:59:59.000Z

403

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

Science Conference Proceedings (OSTI)

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

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

2011-10-17T23:59:59.000Z

404

Simultaneous ionization-excitation of helium to He ,,2p... magnetic sublevels by proton impact  

E-Print Network (OSTI)

-5698 Received 3 October 2001; published 12 December 2001 Experimental magnetic substate cross section ratios 0 ionization- excitation mechanism from the He(1s2 ) 1 S ground state to the final ionic state He (2p) 2 P0

Godunov, Alexander L.

405

Solar Activity and Cloud Opacity Variations: A Modulated Cosmic Ray Ionization Model  

Science Conference Proceedings (OSTI)

The observed correlation between global low cloud amount and the flux of high energy cosmic rays supports the idea that ionization plays a crucial role in tropospheric cloud formation. This idea is explored quantitatively with a simple model ...

David Marsden; Richard E. Lingenfelter

2003-02-01T23:59:59.000Z

406

Study on the Properties of Ionized Metal Plasma Methodology on Titanium  

Science Conference Proceedings (OSTI)

Ionized Metal Plasma (IMP) deposition was used in depositing metal interconnection of titanium metal film. Inductively coupled plasma (ICP) was attached to chamber wall where it creates an electromagnetic field, thus, ionizing the sputtered metal atoms from target. The film morphology was observed by scanning electron microscope (SEM). Acoustic measurement of titanium film thickness showed that there was a comparable result with film resistance measured by 4-point probe. Results show that higher plasma density would cause tensile properties on the film stress.

Leow, M. T. [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Infineon Technologies (Kulim) Sdn Bhd, Lot 10 and 11, Jalan Hi-Tech 7, Industrial Zone Phase 2, Kulim Hi-Tech Park, 09000, Kulim, Kedah Darul Aman (Malaysia); Hassan, Z. [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Lee, K. E.; Omar, G.; Lim, S. P.; Chan, C. F.; Siew, E. T.; Chuah, Z. M. [Infineon Technologies (Kulim) Sdn Bhd, Lot 10 and 11, Jalan Hi-Tech 7, Industrial Zone Phase 2, Kulim Hi-Tech Park, 09000, Kulim, Kedah Darul Aman (Malaysia)

2010-07-07T23:59:59.000Z

407

Unexpected photoreactivation of Vibrio harveyi bacteria living in ionization environment  

SciTech Connect

Bacteria undergoing environmental effects is extremely interesting for structural, mechanistic, and evolutionary implications. Luminescent bacteria that have evolved in a specific ambient have developed particular responses and their behavior can give us new suggestions on the task and production of luciferina proteins. To analyze the UV interaction under controlled laboratory conditions, we used photoluminescent bacterial strains belonging to a new species evolutionarily close to Vibrio harveyi sampled from a coastal cave with a high radon content that generates ionizing radiation. The survival of the bacterial strains was analyzed, in the light and in the dark, following a variety of genotoxic treatments including UV radiation exposure. The strains were irradiated by a germicide lamp. The results demonstrated that most of the strains exhibited a low rate of survival after the UV exposure. After irradiation by visible light following the UV exposure, all strains showed a high capability of photoreactivation when grown. This capability was quite unexpected because these bacteria were sampled from a dark ambient without UV radiation. This leads us to hypothesize that the photoreactivation in these bacteria might have been evolved to repair DNA lesions also induced by different radiation sources other than UV (e.g., x-ray) and that the luminescent bacteria might use their own light emission to carry out the photoreactivation. The high capability of photoreactivation of these bacteria was also justified by the results of deconvolution. The deconvolution was applied to the emission spectra and it was able to show evidence of different light peaks. The presence of the visible peak could control the photolysis enzyme.

Alifano, P.; Tala, A.; Tredici, S. M. [Dipartimento Microbiologia, Di.S.Te.B.A., Universita del Salento, via Provinciale Lecce-Monteroni, C.P. 193, 73100 Lecce (Italy); Nassisi, V. [Laboratorio di Elettronica Applicata e Strumentazione, LEAS, Dipartimento di Fisica, Universita del Salento and INFN-Lecce, Via Provinciale Lecce-Monteroni, 73100 Lecce (Italy); Siciliano, M. V. [Laboratorio di Elettronica Applicata e Strumentazione, LEAS, Dipartimento di Fisica, Universita del Salento and INFN-Lecce, Via Provinciale Lecce-Monteroni, 73100 Lecce (Italy); Dipartimento di Scienza dei Materiali, University of Salento, via Provinciale Lecce- Monteroni, C.P. 193, 73100 Lecce (Italy)

2011-05-15T23:59:59.000Z

408

Ionizing radiation risks to satellite power systems (SPS) workers  

DOE Green Energy (OSTI)

The radiation risks to the health of workers who will construct and maintain solar power satellites in the space environment were examined. For ionizing radiation, the major concern will be late or delayed health effects, particularly the increased risk of radiation-induced cancer. The estimated lifetime risk for cancer is 0.8 to 5.0 excess deaths per 10,000 workers per rad of exposure. Thus, for example, in 10,000 workers who completed ten missions with an exposure of 40 rem per mission, 320 to 2000 additional deaths in excess of the 1640 deaths from normally occurring cancer, would be expected. These estimates would indicate a 20 to 120% increase in cancer deaths in the worker-population. The wide range in these estimates stems from the choice of the risk-projection model and the dose-response relationsip. The choice between a linear and a linear-quadratic dose-response model may alter the risk estimate by a factor of about two. The method of analysis (e.g., relative vs absolute risk model) can alter the risk estimate by an additional factor of three. Choosing different age and sex distributions can further change the estimate by another factor of up to three. The potential genetic consequences could be of significance, but at the present time, sufficient information on the age and sex distribution of the worker population is lacking for precise estimation of risk. The potential teratogenic consequences resulting from radiation are considered significant. Radiation exposure of a pregnant worker could result in developmental abnormalities.

Lyman, J.T.; Ainsworth, E.J.; Alpen, E.L.; Bond, V.; Curtis, S.B.; Fry, R.J.M.; Jackson, K.L.; Nachtwey, S.; Sondhaus, C.; Tobias, C.A.; Fabrikant, J.I.

1980-11-01T23:59:59.000Z

409

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

E-Print Network (OSTI)

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 of intensities inherent in all laser beams reduces the resolution of this information. This research focuses on recovering the intensity-resolved ATI spectra from experimental data using a deconvolution algorithm. Electron ionization yields of xenon were measured for a set of laser pulse intensities using a time of flight (TOF) setup. Horizontally polarized, unchirped, 50fs pulses were used in the ionization process. All laser parameters other than the radiation intensity were held constant over the set of intensity measurements. A deconvolution algorithm was developed based on the experimental parameters. Then the deconvolution algorithm was applied to the experimental data to obtain the intensity-resolved total yield probability and ATI spectra. Finally, an error analysis was performed to determine the stability and accuracy of the algorithm as well as the quality of the data. It was found that the algorithm produced greater contrast for peaks in the ATI spectra where atom specific resonant behavior is observed. Additionally, the total yield probability showed that double ionization may be observed in the ionization yield. The error analysis revealed that the algorithm was stable under the experimental conditions for a range of intensities.

Hart, Nathan Andrew

2011-08-01T23:59:59.000Z

410

Two-photon double ionization of the helium atom by ultrashort pulses  

SciTech Connect

Two-photon double ionization of the helium atom was the subject of early experiments at FLASH and will be the subject of future benchmark measurements of the associated electron angular and energy distributions. As the photon energy of a single femtosecond pulse is raised from the threshold for two-photon double ionization at 39.5 eV to beyond the sequential ionization threshold at 54.4 eV, the electron ejection dynamics change from the highly correlated motion associated with nonsequential absorption to the much less correlated sequential ionization process. The signatures of both processes have been predicted in accurate \\textit{ab initio} calculations of the joint angular and energy distributions of the electrons, and those predictions contain some surprises. The dominant terms that contribute to sequential ionization make their presence apparent several eV below that threshold. In two-color pump probe experiments with short pulses whose central frequencies require that the sequential ionization process necessarily dominates, a two-electron interference pattern emerges that depends on the pulse delay and the spin state of the atom.

Palacios, Alicia; Horner, Daniel A; Rescigno, Thomas N; McCurdy, C William

2010-05-14T23:59:59.000Z

411

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

DOE Patents (OSTI)

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

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

2009-05-12T23:59:59.000Z

412

Ionization and scintillation response of high-pressure xenon gas to alpha particles  

E-Print Network (OSTI)

High-pressure xenon gas is an attractive detection medium for a variety of applications in fundamental and applied physics. In this paper we study the ionization and scintillation detection properties of xenon gas at 10 bar pressure. For this purpose, we use a source of alpha particles in the NEXT-DEMO time projection chamber, the large scale prototype of the NEXT-100 neutrinoless double beta decay experiment, in three different drift electric field configurations. We measure the ionization electron drift velocity and longitudinal diffusion, and compare our results to expectations based on available electron scattering cross sections on pure xenon. In addition, two types of measurements addressing the connection between the ionization and scintillation yields are performed. On the one hand we observe, for the first time in xenon gas, large event-by-event correlated fluctuations between the ionization and scintillation signals, similar to that already observed in liquid xenon. On the other hand, we study the field dependence of the average scintillation and ionization yields. Both types of measurements may shed light on the mechanism of electron-ion recombination in xenon gas for highly-ionizing particles. Finally, by comparing the response of alpha particles and electrons in NEXT-DEMO, we find no evidence for quenching of the primary scintillation light produced by alpha particles in the xenon gas.

NEXT Collaboration; V. Álvarez; F. I. G. M. Borges; S. Cárcel; S. Cebrián; A. Cervera; C. A. N. Conde; T. Dafni; J. Díaz; M. Egorov; R. Esteve; P. Evtoukhovitch; L. M. P. Fernandes; P. Ferrario; A. L. Ferreira; E. D. C. Freitas; V. M. Gehman; A. Gil; A. Goldschmidt; H. Gómez; J. J. Gómez-Cadenas; D. González-Díaz; R. M. Gutiérrez; J. Hauptman; J. A. Hernando Morata; D. C. Herrera; 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; T. Miller; A. Moiseenko; F. Monrabal; C. M. B. Monteiro; F. J. Mora; L. M. Moutinho; J. Muñoz Vidal; H. Natal da Luz; G. Navarro; M. Nebot-Guinot; D. Nygren; C. A. B. Oliveira; R. Palma; J. Pérez; J. L. Pérez Aparicio; J. Renner; L. Ripoll; A. Rodríguez; J. Rodríguez; F. P. Santos; J. M. F. dos Santos; L. Segui; L. Serra; D. Shuman; A. Simón; C. Sofka; M. Sorel; J. F. Toledo; A. Tomás; J. Torrent; Z. Tsamalaidze; D. Vázquez; J. F. C. A. Veloso; R. Webb; J. T White; N. Yahlali

2012-11-19T23:59:59.000Z

413

Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides  

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

Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides Print Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides Print "Ferroelectricity," by analogy to ferromagnetism, is defined as the presence of spontaneous electrical polarization in a material, often arising from distortions in the material's crystal structure. In oxides of the metals lead and bismuth, such distortions were for many years attributed to the existence of "lone pair" electrons: pairs of chemically inert, nonbonding valence electrons in hybrid orbitals that leave noticeable voids in the crystal structure. At the ALS, researchers from the U.K., Ireland, and the U.S. have now obtained definitive experimental evidence that this lone-pair model must be revised. High-resolution x-ray photoemission spectroscopy (XPS) and soft x-ray emission spectroscopy (XES) have clarified the subtle electronic origins of the prototypical distortions in these crystal structures. The results have important implications for the tantalizing possibility of spintronic or superconducting devices combining ferroelectric and ferromagnetic properties.

414

Signature of a Pairing Transition in the Heat Capacity of Finite Nuclei  

E-Print Network (OSTI)

The heat capacity of iron isotopes is calculated within the interacting shell model using the complete (pf + 0g9/2)-shell. We identify a signature of the pairing transition in the heat capacity that is correlated with the suppression of the number of spin-zero neutron pairs as the temperature increases. Our results are obtained by a novel method that significantly reduces the statistical errors in the heat capacity calculated by the shell model Monte Carlo approach. The Monte Carlo results are compared with finite-temperature Fermi gas and BCS calculations. Typeset using REVTEX 1 Pairing effects in finite nuclei are well known; examples include the energy gap in the spectra of even-even nuclei and an odd-even effect observed in nuclear masses. However, less is known about the thermal signatures of the pairing interaction in nuclei. In a macroscopic conductor, pairing leads to a phase transition from a normal metal to a superconductor below a certain critical temperature, and in the BCS theory [1] the heat capacity is characterized

S. Liu; Y. Alhassid

2000-01-01T23:59:59.000Z

415

Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides  

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

Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides Print Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides Print "Ferroelectricity," by analogy to ferromagnetism, is defined as the presence of spontaneous electrical polarization in a material, often arising from distortions in the material's crystal structure. In oxides of the metals lead and bismuth, such distortions were for many years attributed to the existence of "lone pair" electrons: pairs of chemically inert, nonbonding valence electrons in hybrid orbitals that leave noticeable voids in the crystal structure. At the ALS, researchers from the U.K., Ireland, and the U.S. have now obtained definitive experimental evidence that this lone-pair model must be revised. High-resolution x-ray photoemission spectroscopy (XPS) and soft x-ray emission spectroscopy (XES) have clarified the subtle electronic origins of the prototypical distortions in these crystal structures. The results have important implications for the tantalizing possibility of spintronic or superconducting devices combining ferroelectric and ferromagnetic properties.

416

Mechanics and Dynamics of X-Chromosome Pairing at X Inactivation  

E-Print Network (OSTI)

At the onset of X Chromosomes Inactivation, the vital process whereby female mammal cells equalize X products with respect to males, the X chromosomes are colocalized along their Xic (X-Inactivation Center) regions. The mechanism inducing recognition and pairing of the X's remains, though, elusive. Starting from recent discoveries on the molecular factors and on the DNA sequences (the so-called ``pairing sites'') involved, we dissect the mechanical basis of Xic colocalization by using a Statistical Physics model. We show that soluble DNA specific binding molecules, as those experimentally identified, can be indeed sufficient to induce the spontaneous colocalization of the homologous chromosomes, but only when their concentration, or chemical affinity, rises above a threshold value, as a consequence of a thermodynamic phase transition. We derive the likelihood of pairing and its probability distribution. Chromosome dynamics has two stages: an initial independent Brownian diffusion followed, after a characteristic time scale, by recognition and pairing. Finally, we investigate the effects of DNA deletion/insertions in the region of pairing sites and compare model predictions to available experimental data.

A. Scialdone; M. Nicodemi

2009-10-13T23:59:59.000Z

417

Interesting features of nonlinear shock equations in dissipative pair-ion-electron plasmas  

SciTech Connect

Two dimensional nonlinear electrostatic waves are studied in unmagnetized, dissipative pair-ion-electron plasmas in the presence of weak transverse perturbation. The dissipation in the system is taken into account by incorporating the kinematic viscosity of both positive and negative ions. In the linear case, a biquadratic dispersion relation is obtained, which yields the fast and slow modes in a pair-ion-electron plasma. It is shown that the limiting cases of electron-ion and pair-ion can be retrieved from the general biquadratic dispersion relation, and the differences in the characters of the waves propagating in both the cases are also highlighted. Using the small amplitude approximation method, the nonlinear Kadomtsev Petviashvili Burgers as well as Burgers-Kadomtsev Petviashvili equations are derived and their applicability for pair-ion-electron plasma is explained in detail. The present study may have relevance to understand the formation of two dimensional electrostatic shocks in laboratory produced pair-ion-electron plasmas.

Masood, W. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad 54000 (Pakistan); National Centre for Physics (NCP), Shahdara Valley Road, 44000 Islamabad (Pakistan); Rizvi, H. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad 54000 (Pakistan)

2011-09-15T23:59:59.000Z

418

Optimizing electron-positron pair production on kilojoule-class high-intensity lasers for the purpose of pair-plasma creation  

Science Conference Proceedings (OSTI)

Expressions for the yield of electron-positron pairs, their energy spectra, and production rates have been obtained in the interaction of multi-kJ pulses of high-intensity laser light interacting with solid targets. The Bethe-Heitler conversion of hard x-ray bremsstrahlung [D. A. Gryaznykh, Y. Z. Kandiev, and V. A. Lykov, JETP Lett. 67, 257 (1998); K. Nakashima and H. Takabe, Phys. Plasmas 9, 1505 (2002)] is shown to dominate over direct production (trident process) [E. P. Liang, S. C. Wilks, and M. Tabak, Phys. Rev. Lett. 81, 4887 (1998)]. The yields and production rates have been optimized as a function of incident laser intensity by the choice of target material and dimensions, indicating that up to 5x10{sup 11} pairs can be produced on the OMEGA EP laser system [L. J. Waxer et al., Opt. Photonics News 16, 30 (2005)]. The corresponding production rates are high enough to make possible the creation of a pair plasma.

Myatt, J.; Delettrez, J. A.; Maximov, A. V.; Meyerhofer, D. D.; Short, R. W.; Stoeckl, C.; Storm, M. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States)

2009-06-15T23:59:59.000Z

419

Probing Material Reactivity Using X-ray Pair Distribution Function Methods  

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

Material Reactivity Using X-ray Pair Distribution Material Reactivity Using X-ray Pair Distribution Function Methods Karena W. Chapman X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA Understanding how advanced functional materials react and transform, at an atomic scale, is a characterization challenge with many diverse phenomena possible; components with varying particle size, morphology, and microstructure can evolve from multi-atom clusters to multi-million atom crystals. The pair distribution function (PDF) method shows great promise for providing quantitative insight such reactions. Recent advances in experimental methods, have improved the efficiency of X-ray PDF measurements, to allow time-resolved experiments with sufficient resolution to study reactions in solid

420

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

SciTech Connect

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

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

2008-06-19T23:59:59.000Z

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421

A Method for Constructing a Lax Pair for the Ernst Equation  

E-Print Network (OSTI)

A systematic construction of a Lax pair and an infinite set of conservation laws for the Ernst equation is described. The matrix form of this equation is rewritten as a differential ideal of gl(2,R)-valued differential forms, and its symmetry condition is expressed as an exterior equation which is linear in the symmetry characteristic and has the form of a conservation law. By means of a recursive process, an infinite collection of such laws is then obtained, and the conserved "charges" are used to derive a linear exterior equation whose components constitute a Lax pair.

C. J. Papachristou; B. Kent Harrison

2008-05-09T23:59:59.000Z

422

Signature of a Pairing Transition in the Heat Capacity of Finite Nuclei  

E-Print Network (OSTI)

The heat capacity of iron isotopes is calculated within the interacting shell model using the complete $(pf+0g_{9/2})$-shell. We identify a signature of the pairing transition in the heat capacity that is correlated with the suppression of the number of spin-zero neutron pairs as the temperature increases. Our results are obtained by a novel method that significantly reduces the statistical errors in the heat capacity calculated by the shell model Monte Carlo approach. The Monte Carlo results are compared with finite-temperature Fermi gas and BCS calculations.

S. Liu; Y. Alhassid

2000-09-05T23:59:59.000Z

423

Extrinsic orbital angular momentum of entangled photon-pairs in spontaneous parametric down-conversion  

E-Print Network (OSTI)

Starting from the standard Hamiltonian describing the optical non-linear process of spontaneous parametric down-conversion, we theoretically show that the generated entangled photon-pairs carry non-negligible orbital angular momentum in the degrees of freedom of relative movement in the type-II cases due to spatial symmetry breaking. We also show that the orbital angular momentum carried by photon-pairs in these degrees of freedom escapes detection in the traditional measurement scheme, which demands development of new techniques for further experimental investigations.

Sheng Feng; Prem Kumar

2008-05-13T23:59:59.000Z

424

P-wave contribution to third-order top-quark pair production near threshold  

E-Print Network (OSTI)

The next-to-leading order (NLO) P-wave Coulomb Green function contributes at third-order to top-pair production in e+ e- collisions near threshold. In this paper we compute the NLO P-wave Green function in dimensional regularization, as required for a consistent combination with non-resonant production of the W+ W- b\\bar{b} final state, and present a phenomenological analysis of the P-wave contribution. We further briefly discuss squark production near threshold and top-pair production in gamma gamma collisions, where no S-wave contribution is present, and the P-wave thus constitutes the dominant production process.

M. Beneke; J. Piclum; T. Rauh

2013-12-17T23:59:59.000Z

425

Slow light enhanced correlated photon pair generation in photonic-crystal coupled-resonator optical waveguides  

E-Print Network (OSTI)

We demonstrate the generation of quantum-correlated photon pairs from a Si photonic-crystal coupled-resonator optical waveguide. A slow-light supermode realized by the collective resonance of high-Q and small-mode-volume photonic-crystal cavities successfully enhanced the efficiency of the spontaneous four-wave mixing process. The generation rate of photon pairs was improved by two orders of magnitude compared with that of a photonic-crystal line defect waveguide without a slow-light effect.

Matsuda, Nobuyuki; Shimizu, Kaoru; Tokura, Yasuhiro; Kuramochi, Eiichi; Notomi, Masaya; 10.1364/OE.21.008596

2013-01-01T23:59:59.000Z

426

Pairing in 4-component fermion systems: the bulk limit of SU(4)-symmetric Hamiltonians  

E-Print Network (OSTI)

Fermion systems with more than two components can exhibit pairing condensates of much more complex structure than the well-known single BCS condensate of spin-up and spin-down fermions. In the framework of the exactly solvable SO(8) Richardson-Gaudin model with SU(4)-symmetric Hamiltonians, we show that the BCS approximation remains valid in the thermodynamic limit of large systems for describing the ground state energy and the canonical and quasiparticle excitation gaps. Correlations beyond BCS pairing give rise to a spectrum of collective excitations, but these do not affect the bulk energy and quasiparticle gaps.

Bertsch, G F; Errea, B; Esebbag, C

2009-01-01T23:59:59.000Z

427

Two Higgs Pair Heterotic Vacua and Flavor-Changing Neutral Currents  

E-Print Network (OSTI)

We present a vacuum of heterotic M-theory whose observable sector has the MSSM spectrum with the addition of one extra pair of Higgs-Higgs conjugate superfields. The quarks/leptons have a realistic mass hierarchy with a naturally light first family. The double elliptic structure of the Calabi-Yau compactification threefold leads to two ``stringy'' selection rules. These classically disallow Yukawa couplings to the second Higgs pair and, hence, Higgs mediated flavor-changing neutral currents. Such currents are induced in higher-dimensional interactions, but are naturally suppressed. We show that our results fit comfortably below the observed upper bounds on neutral flavor-changing processes.

Michael Ambroso; Volker Braun; Burt A. Ovrut

2008-07-21T23:59:59.000Z

428

Validity of pair truncation of the nuclear shell model in {sup 46}Ca  

SciTech Connect

We study the validity of pair truncation of the nuclear shell model by using the semimagic nucleus {sup 46}Ca. We present low-lying states and their E2 transition rates based on both nucleon pair approximation (NPA) and exact shell-model (SM) calculations. We also calculate overlaps between wave functions of low-lying states calculated by using the NPA and those calculated by using the SM. Our calculated results show a remarkable agreement between the NPA results and the SM results, although the NPA is a drastic truncation of the SM.

Lei, Y.; Xu, Z. Y. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhao, Y. M. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China); CCAST, World Laboratory, Post Office Box 8730, Beijing 100080 (China); Arima, A. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Science Museum, Japan Science Foundation, 2-1 Kitanomaru-koen, Chiyoda-ku, Tokyo 102-0091 (Japan)

2009-12-15T23:59:59.000Z

429

Coherently manipulating two-qubit quantum information using a pair of simultaneous laser pulses  

E-Print Network (OSTI)

Several sequential operations are usually needed for implementing controlled quantum gates and generating entanglement between a pair of quantum bits. Based on the conditional quantum dynamics for a two-ion system beyond the Lamb-Dicke limit, here we propose a theoretical scheme for manipulating two-qubit quantum information, i.e., implementing a universal two-qubit quantum gate and generating a two-qubit entangled state, by using a pair of simultaneous laser pulses. Neither the Lamb-Dicke approximation nor the auxiliary atomic level are required. The experimental realizability of this simple approach is also discussed.

L. F. Wei; Franco Nori

2004-11-18T23:59:59.000Z

430

Study of correlations between photoproduced pairs of charmed particles at Experiment E831/FOCUS  

SciTech Connect

The authors present the study of the charm-pair correlations produced in photon-nucleon interactions at = 175 GeV/c, by the Fermilab fixed target experiment E831/FOCUS. The E831/FOCUS experiment produced and reconstructed over one million charm particles. This high statistics allows the reconstruction of more than 7000 charm-pair mesons D{bar D}, 10 times the statistic of former experiments, and also allows to get, for the first time, about 600 totally reconstructed charm-pairs in the DD{sub s} and D{Lambda}{sub c} channels. They were able to study, with some detail, the kinematical correlations between the charm and anticharm particle forming a pair, in the square transverse momentum (p{sub T}{sup 2}), azimuthal angle difference ({Delta}{phi}), rapidity difference ({Delta}y) and the charm-pair mass variables. They observe some correlation for the longitudinal momenta, and a significant correlation for the transverse momenta of the charm and anticharm particles. They compare the experimental distributions with theoretical predictions based on the photon-gluon fusion model (PGF), for the production of c{bar c} quarks, and the standard Lund hadronization model. These models are implemented by the PYTHIA Monte Carlo event generator. The PYTHIA program allows the inclusion, in the simulation, of non-perturbative effects that have been shown to be important for charm production. In order to compare data and simulation, they have generated two Monte Carlo samples, the first one set to favor the production of D{bar D} pairs (MCDD2), and the second one set to favor the production of DD{sub s} and D{Lambda}{sub c} pairs, where each one uses different functions and parameters values for the theoretical models in the simulation. They observe, for the correlation distributions, that the set of parameters used by the MCDD2 model together with the intrinsic transverse momentum (k{sub {perpendicular}}) of the partons inside the nucleons, has a better agreement with data distributions than the one used by the MCDSLC model. Finally, the relative pair/anti-pair yield production ratio is calculated for five sets of charm-pairs, D{sup +}D{sup 0}, D{sup +}D{sub s}{sup -}, D{sup 0}D{sub s}{sup -}, D{sup +}{Lambda}{sub c}{sup -} e D{sup 0}{Lambda}{sub c}{sup -}, both for data as well as for the two Monte Carlo samples. They observe that the MCDSLC model predicts charm-pair yield production ratios closer to the yield ratios data than the MCDD2 model.

Castromonte Flores, Cesar Manuel; /Rio de Janeiro, CBPF

2008-08-01T23:59:59.000Z

431

Double and single ionization of He and H{sub 2} by slow protons and antiprotons  

DOE Green Energy (OSTI)

Double and single ionization of He and H{sub 2} by proton (p) and antiproton ({bar p})impact in the energy region below 50 keV was studied theoretically by using the semiclassical molecular picture. As the energy decreased, the ratio of the double- to the single-ionization cross section increased for impact and decreased for p impact for both He and H{sub 2}. These trends are consistent with recent measurements for He. Ionization mechanisms differ distinctly for p impact and {bar p} impact. For p impact, the dominant mechanism for double ionization at the lower energies is sequential ladder climbing by the two electrons through various excited channels and finally into the continuum. For {bar p} impact, in contrast, the approaching negative charge distorts both the He and H{sub 2} electron clouds toward the other side of the nucleus and decreases the electron binding energies. These effects enhance electron-electron interactions, increasing double ionization. For the H{sub 2}, an effect of molecular orientation is an additional complication in determining the dynamics.

Kimura, Mineo [Argonne National Lab., IL (United States)]|[Rice Univ., Houston, TX (United States). Dept. of Physics; Shimamura, Isao [Riken, Inc., Wako, Saitama (Japan). Institute of Physical and Chemical Research; Inokuti, Mitio [Argonne National Lab., IL (United States)

1994-12-31T23:59:59.000Z

432

Ionization of Stark states with half-cycle pulses: Interference effects in the continuum  

SciTech Connect

We study the ionization of extreme Stark states in sodium by THz electromagnetic half-cycle pulses. The results of our full-quantum calculations reveal the presence of an oscillatory pattern in the ionization spectra of extreme red (downhill) states that have been kicked away from the ion core (downhill with respect to the potential imposed by the Stark field). We find no oscillations in the spectra of extreme blue (uphill) states that have been kicked towards the ion core (also downhill with respect to the Stark potential). The oscillatory pattern in the red state ionization spectra is explained with a one-dimensional semiclassical model in terms of interferences between two classical paths. This model also predicts that the blue state ionization spectra should also show oscillatory behavior. The absence of the oscillations in the full calculations can be regarded as a breakdown of the one-dimensional model in representing the ionization dynamics of these states. We find that the one-dimensional model fails when the duration of the THz pulse is comparable to the classical Kepler orbit time.

Manescu, Corneliu; Krause, Jeffrey L. [Quantum Theory Project, University of Florida, Gainesville, Florida 32611-8435, USA (United States); Schafer, Kenneth J. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803-4001, USA (United States)

2003-07-01T23:59:59.000Z

433

Grain size distributions and photo-electric heating in ionized media  

E-Print Network (OSTI)

Ever since the pioneering study of Spitzer, it has been widely recognized that grains play an important role in the heating and cooling of photo-ionized environments. A detailed code is necessary to model grains in a photo-ionized medium. In this paper we will use the spectral synthesis code Cloudy for this purpose. The grain model of this code has recently undergone a comprehensive upgrade. Part of this is the newly developed hybrid grain charge model, which will be described in detail. This model allows discrete charge states of very small grains to be modelled accurately while simultaneously avoiding the overhead of fully resolving the charge distribution of large grains, thus making the model both accurate and computationally efficient. A comprehensive comparison with the fully resolved charge state models of Weingartner & Draine (2001) shows that the agreement is very satisfactory for realistic size distributions. The effect of the grain size distribution on the line emission from photo-ionized regions is studied by taking standard models for an H II region and a planetary nebula and adding a dust component to the models with varying grain size distributions. A comparison of the models shows that varying the size distribution has a dramatic effect on the emitted spectrum, and affects the ionization balance as well. These results clearly demonstrate that the grain size distribution is an important parameter in photo-ionization models.

P. A. M. van Hoof; J. C. Weingartner; P. G. Martin; K. Volk; G. J. Ferland

2004-02-16T23:59:59.000Z

434

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

E-Print Network (OSTI)

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

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

2007-09-24T23:59:59.000Z

435

Pulse mode readout techniques for use with non-gridded industrial ionization chambers  

SciTech Connect

Highly sensitive readout technique for precision long-term radiation measurements has been developed and tested in the Radiation Control Department at Jefferson Lab. The new electronics design is used to retrieve ionization data in a pulse mode. The dedicated data acquisition system works with M=Audio Audiophile 192 High-Definition 24-bit/192 kHz audio cards, taking data in continuous waveform recording mode. The on-line data processing algorithms extract signals of the ionization events from the data flow and measure the ionization value for each event. Two different ion chambers are evaluated. The first is a Reuter-Stokes Argon-filled (at 25 atm) High Pressure Ionization Chamber (HPIC), commonly used as a detector part in many GE Reuter-Stokes instruments of the RSS series. The second is a VacuTec Model 70181, 5 atm Xenon-filled ionization chamber. Results for both chambers indicate that the techniques allow using industrial ICs for high sensitivity and precision long-term radiation measurements, while at the same time providing information about spectral characteristics of the radiation fields.

Popov, Vladimir E. [JLAB; Degtiarenko, Pavel V. [JLAB

2011-10-01T23:59:59.000Z

436

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

E-Print Network (OSTI)

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.

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

2013-01-01T23:59:59.000Z

437

Next-to-leading order QCD corrections to light Higgs Pair production via vector boson fusion  

E-Print Network (OSTI)

We present the NLO QCD corrections for light Higgs pair production via vector boson fusion at the LHC within the CP conserving type II two higgs doublet model in the form of a fully flexible parton--level Monte Carlo program. Scale dependences on integrated cross sections and distributions are reduced with QCD K-factors of order unity.

Terrance Figy

2008-06-13T23:59:59.000Z

438

QCD Corrections to Vector Boson Pair Production via Weak Boson Fusion  

E-Print Network (OSTI)

NLO-QCD corrections to vector boson pair production via weak boson fusion have recently been calculated and implemented into flexible parton-level Monte-Carlo programs. These allow for the computation of cross sections and kinematical distributions within realistic experimental cuts. We summarize the basic elements of the calculation and review phenomenological results for the LHC.

B. Jager; C. Oleari; D. Zeppenfeld

2006-08-24T23:59:59.000Z

439

Iterated Peiffer pairings in the Moore complex of a simplicial group.  

E-Print Network (OSTI)

We introduce a pairing structure within the Moore complex NG of a simplicial group G and use it to investigate generators for NG_n\\cap D_n where D_n is the subgroup generated by degenerate elements. This is applied to the study of algebraic models for homotopy types.

A Mutlu; T Porter.

440

The Computation of Cloud-Base Height from Paired Whole-Sky Imaging Cameras  

Science Conference Proceedings (OSTI)

The authors have developed a novel approach to the extraction of cloud-base height (CBH) from pairs of whole-sky images. The core problem is to spatially register cloud fields from widely separated whole-sky imaging (WSI) cameras; this complete ...

Mark C. Allmen; W. Philip Kegelmeyer Jr.

1996-02-01T23:59:59.000Z

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


441

Fixing variable values in the capacitated facility location problem through pairing and surrogate constraint analysis  

Science Conference Proceedings (OSTI)

The Osorio and Glover (2003) use of dual surrogate analysis is exploited to fix variables in capacitated facility location problems (CFLP). The surrogate constraint is obtained by weighting the original problem constraints by their associated dual values ... Keywords: capacitated facility location problem, constraint pairing, duality, surrogate constraints

Maria A. Osorio; Abraham Sánchez

2009-06-01T23:59:59.000Z

442

Afterglow emission from pair-loaded blast waves in gamma-ray bursts  

E-Print Network (OSTI)

The MeV radiation front of gamma-ray bursts creates copious e+- pairs as it propagates through an ambient medium. The created pairs enrich the leptonic component of the medium by a large factor at distances R load ~ 10^{16} cm from the burst center. The following blast wave sweeps up the pair-rich medium and then emits the observed afterglow radiation. We find that the afterglow has a "memory" of e+- loading outside R_load. The e+- pairs remain in the swept-up material and slowly cool down by emitting synchrotron radiation. They are likely to dominate the blast-wave emission in IR, optical, and UV bands during the first minutes of the observed afterglow. The expected e+- radiation is described by a simple formula, which is derived analytically and checked by numerical integration of synchrotron emission over the blast material; a suitable Lagrangian formalism is developed for such calculations. The main signature of e+- radiation is its flat ("white") spectrum in a broad range of frequencies from IR to UV and possibly soft X-rays. This radiation can be detected by Swift satellite, which would enable new observational tests for the explosion physics.

Andrei M. Beloborodov

2005-03-02T23:59:59.000Z

443

Stable pinching by a pair of robot fingers with soft tips under the effect of gravity  

Science Conference Proceedings (OSTI)

This paper analyses lumped-parameter dynamics of a pair of robot fingers with soft and deformable tips pinching a rigid object under the effect of a gravity force. The dynamics of the system in which area contacts between the finger-tips and the surfaces ... Keywords: Gravity, Lumped-parameter dynamics, Robot fingers, Soft tips, Stable pinching

Suguru Arimoto; Zoe Doulgeri; Pham Thuc Anh Nguyen; John Fasoulas

2002-05-01T23:59:59.000Z

444

The Jones-Hore theory of radical-ion-pair reactions is not self-consistent  

E-Print Network (OSTI)

It is shown that the master equation introduced by Jones & Hore and purported to describe radical-ion-pair reactions is not self-consistent. This is because the average of single-molecule realizations does not reproduce the predictions of the master equation.

Kominis, I K

2010-01-01T23:59:59.000Z

445

Analyses of humanchimpanzee orthologous gene pairs to explore evolutionary hypotheses of aging  

E-Print Network (OSTI)

Analyses of human­chimpanzee orthologous gene pairs to explore evolutionary hypotheses of aging Joa Abstract Compared to chimpanzees (Pan troglodytes), the onset of aging appears to be delayed in the human acting on genes associated with aging in different model systems, which allowed us to explore

Church, George M.

446

A Paired-Orientation Alignment Problem in a Hybrid Tracking System for Computer Assisted Surgery  

Science Conference Proceedings (OSTI)

Coordinate Alignment (CA) is an important problem in hybrid tracking systems involving two or more tracking devices. CA typically associates the measurements from two or more tracking systems with respect to distinct base frames and makes them comparable ... Keywords: Computer assisted surgery (CAS), Coordinate alignment, Paired-Orientation Alignment (POA), Quaternions, Surgical navigation

Hongliang Ren; Peter Kazanzides

2011-08-01T23:59:59.000Z

447

Construction of Hilbert Transform Pairs of Wavelet Bases and Gabor-like Transforms  

E-Print Network (OSTI)

We propose a novel method for constructing Hilbert transform (HT) pairs of wavelet bases based on a fundamental approximation-theoretic characterization of scaling functions--the B-spline factorization theorem. In particular, starting from well-localized scaling functions, we construct HT pairs of biorthogonal wavelet bases of L^2(R) by relating the corresponding wavelet filters via a discrete form of the continuous HT filter. As a concrete application of this methodology, we identify HT pairs of spline wavelets of a specific flavor, which are then combined to realize a family of complex wavelets that resemble the optimally-localized Gabor function for sufficiently large orders. Analytic wavelets, derived from the complexification of HT wavelet pairs, exhibit a one-sided spectrum. Based on the tensor-product of such analytic wavelets, and, in effect, by appropriately combining four separable biorthogonal wavelet bases of L^2(R^2), we then discuss a methodology for constructing 2D directional-selective complex...

Chaudhury, Kunal Narayan

2009-01-01T23:59:59.000Z

448

CP Asymmetry in the Higgs Decay into the Top Pair Due to the Stop Mixing  

SciTech Connect

We investigate a potentially large CP violating asymmetry in the decay of a neutral scalar or pseudoscalar Higgs boson into the top-anti-top pair. The source of the CP nonconservation is the complex mixing in the (left-right) stop sector. One of the interesting consequence is the different rates of the Higgs boson decays into CP conjugate polarized states.

Chang, Darwin

2001-07-25T23:59:59.000Z

449

Calix[4]pyrrole: A New Ion-Pair Receptor As Demonstrated by Liquid-Liquid Extraction  

SciTech Connect

Solvent extraction studies provide confirming evidence that meso-octamethylcalix[4]pyrrole acts as an ion-pair receptor for cesium chloride and cesium bromide in nitrobenzene solution. The stoichiometry of the interaction under extraction conditions from water to nitrobenzene was determined from plots of the cesium distribution ratios vs. cesium salt and receptor concentration, indicating the formation of an ion-paired 1:1:1 cesium:calix[4]pyrrole:halide complex. The extraction results were modeled to evaluate the equilibria inherent to the solvent extraction system, either with chloride or bromide. The binding energy between the halide anion and the calix[4]pyrrole was found to be about 7 kJ/mol larger for cesium chloride than for the cesium bromide. The ion-pairing free energies between the calix[4]pyrrole-halide complex and the cesium cation are nearly the same within experimental uncertainty for either halide, consistent with a structural model in which the Cs+ cation resides in the calix bowl. These results are unexpected since nitrobenzene is a very polar solvent that generally leads to dissociated complexes in the organic phase when used as a diluent in extraction studies of univalent ions. Control studies involving nitrate revealed no evidence of ion-pairing for CsNO3 under conditions identical to those where it is observed for CsCl and CsBr.

Wintergerst, Mr. Matthieu [Ecole Nationale Superieure de Chimie de Paris; Levitskaia, Tatiana G. [Pacific Northwest National Laboratory (PNNL); Moyer, Bruce A [ORNL; Sessler, Jonathan L. [University of Texas; Delmau, Laetitia Helene [ORNL

2008-01-01T23:59:59.000Z

450

Limits of heralded single photon sources based on parametric photon pair generation  

E-Print Network (OSTI)

We derive calculations on the statistics of a heralded single photon source based on parametric photon pair generation. These calculations highlight fundamental and practical limits for these sources, and show which physical parameters can be optimized to improve the quality of a real source.

Virally, Stéphane; Godbout, Nicolas

2009-01-01T23:59:59.000Z

451

Limits of heralded single photon sources based on parametric photon pair generation  

E-Print Network (OSTI)

We derive calculations on the statistics of a heralded single photon source based on parametric photon pair generation. These calculations highlight fundamental and practical limits for these sources, and show which physical parameters can be optimized to improve the quality of a real source.

Stéphane Virally; Suzanne Lacroix; Nicolas Godbout

2009-10-13T23:59:59.000Z

452

A simple model for the quenching of pairing correlations effects in rigidly deformed rotational bands  

E-Print Network (OSTI)

Using Chandrasekhar's S-type coupling between rotational and intrinsic vortical modes one may simply reproduce the HFB dynamical properties of rotating nuclei within Routhian HF calculations free of pairing correlations yet constrained on the relevant so-called Kelvin circulation operator. From the analogy between magnetic and rotating systems, one derives a model for the quenching of pairing correlations with rotation, introducing a critical angular velocity -- analogous to the critical field in supraconductors -- above which pairing vanishes. Taking stock of this usual model, it is then shown that the characteristic behavior of the vortical mode angular velocity as a function of the global rotation angular velocity can be modelised by a simple two parameter formula, both parameters being completely determined from properties of the band-head (zero-spin) HFB solution. From calculation in five nuclei, the validity of this modelised Routhian approach is assessed. It is clearly shown to be very good in cases where the evolution of rotational properties is only governed by the coupling between the global rotation and the pairing-induced intrinsic vortical currents. It therefore provides a sound ground base for evaluating the importance of coupling of rotation with other modes (shape distortions, quasiparticle degrees of freedom).

P. Quentin; H. Laftchiev; D. Samsoen; I. N. Mikhailov

2003-07-25T23:59:59.000Z

453

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

E-Print Network (OSTI)

Nuclear Physics A 781 (2007) 317­341 Symmetry energies, pairing energies, and mass equations J of the respective mass equation since symmetry energies are related to the curvature of the nuclear mass surface.10.Dr; 21.10.Hw; 21.30.Fe; 21.60.-n Keywords: NUCLEAR STRUCTURE Z = 1­118; analyzed isobaric analog

O'Donnell, Tom

454

Towards laboratory-produced relativistic electron-positron pair-plasmas  

Science Conference Proceedings (OSTI)

Relativistic pair-plasmas and jets are believed to exist in many astrophysical objects and are often invoked to explain energetic phenomena related to Gamma Ray Bursts and Black Holes. On earth, positrons from radioactive isotopes or accelerators are used extensively at low energies (sub-MeV) in areas related to surface science positron emission tomography and basic antimatter science. Experimental platforms capable of producing the high-temperature pair-plasma and high-flux jets required to simulate astrophysical positron conditions have so far been absent. In the last few years, we performed extensive experiments generating positrons with intense lasers where we found that relativistic electron and positron jets are produced by irradiating a solid gold target with an intense picosecond laser pulse. The positron temperatures in directions parallel and transverse to the beam both exceeded 0.5 MeV, and the density of electrons and positrons in these jets are of order 10{sup 16} cm{sup -3} and 10{sup 13} cm{sup -3}, respectively. With the advent of high-energy ultra-short laser pulses, we expect that a charge-neutral, relativistic pair-plasma is achievable, a novel regime of laboratory-produced hot dense matter. This talk will present some details of the laser-produced pair-plasma experiments.

Chen, H; Wilks, S C; Meyerhofer, D D; Beiersdorfer, P; Cauble, R; Dollar, F; Falk, K; Hazi, A; Murphy, C D; Park, J; Seely, J; Szabo, C I; Shepherd, R; Tommasini, R; Zulick, K

2010-08-31T23:59:59.000Z

455

Müller: Modeling the Impact of a Learning Phase on the Business Value of a Pair Programming Project. APSEC 11  

E-Print Network (OSTI)

Abstract. Pair programmers need a ”warmup phase” before the pair can work at full speed. The length of the learning interval varies, depending on how experienced the developers are with pair programming and how familiar they are with each other. We study how large the impact of the lower pair productivity during warmup is on the business value of the pair programming project. To this end, we extend our net present value model for pair programming to explicitly include a learning interval for pairs. We then carry out a simulation study where we vary the shape of the learning curve, the length of the learning interval, the final productivity level of the pairs, the market pressure, and the size of the workforce. Our simulations show that the cost of the warmup phase is reasonably small compared to the project value, but nonetheless must be taken into account when estimating the project. Our results also suggest that the learning overhead is not an obstacle to introducing and using pair programming in a real environment.

Frank Padberg

2004-01-01T23:59:59.000Z

456

Influence of pairing on the distribution of independent yield strengths in neutron-induced fission  

SciTech Connect

This report is a summary of the current status of an ongoing investigation of the influence of the pairing force in the distribution of independent yields. At this time pairing systematics have been obtained for /sup 235/U thermal and fast fission yields by a comparison of experimental data to the normal yield curves predicted by the phenomenological model. A semiempirical formalism has been developed and tested (insofar as the available data permits) by which estimates for the magnitudes of the pairing effects can be easily incorporated into the version of the phenomenological model to be used in the ENDF/B-V Fission Product Evaluated Data File. The formalism is based upon the /sup 235/U thermal and fast fission data analysis and has been extended to other proposed ENDF/B-V fissionable nuclides. Neutron energy dependence has been incorporated (in a simple fashion) in terms of excitation energies of the compound system and measured fission barriers. Again, the energy dependence has been expressed in a manner which is easily assimilated by the ENDF/B-V yield model. The initial efforts in this study have been governed by the need to include some quantitative description of the pairing effects within the framework of the existing phenomenological treatment. The results reported herein are thus empirically based and it is to be expected that they will change with the accumulation of more (and better) data. Hopefully this work will provide important clues to a more detailed calculation of the pairing influence as well as other theoretical work in progress.

Madland, D.G.; England, T.R.

1976-07-01T23:59:59.000Z

457

Molecular mechanisms and cellular consequences of low-dose exposure to ionizing  

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

mechanisms and cellular consequences of low-dose exposure to ionizing mechanisms and cellular consequences of low-dose exposure to ionizing radiation Andrew J. Wyrobek 1 , Francesco Marchetti 1 , Xiu Lowe 1 , Xiaochen Lu 2 , Terumi Kohwi- Shigematsu 1 , Brian Davy 1 , Thomas E. Schmid 1 , Sylvia Ahn 1 , Tarlochan Nijjar 1 Matthew A. Coleman 2 , Contact information: ajwyrobek@gmail.com 1 Life Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 2 BioSciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA. The objectives of this research are to characterize the genome-wide molecular responses to low-dose ionizing radiation (<10cGy), to identify tissue and cell-type specific differences in pathways responses, and to identify the pivotal molecular pathway responses that control risks to genome integrity and health. This project utilizes mouse in

458

Heating of ions by low-frequency Alfv\\'{e}n waves in partially ionized plasmas  

E-Print Network (OSTI)

In the solar atmosphere, the chromospheric and coronal plasmas are much hotter than the visible photosphere. The heating of the solar atmosphere, including the partially ionized chromosphere and corona, remains largely unknown. In this paper we demonstrate that the ions can be substantially heated by Alfv\\'{e}n waves with very low frequencies in partially ionized low beta plasmas. This differs from other Alfv\\'{e}n wave related heating mechanisms such as ion-neutral collisional damping of Alfv\\'{e}n waves and heating described by previous work on resonant Alfv\\'{e}n wave heating. In this paper, we find that the non-resonant Alfv\\'{e}n wave heating is less efficient in partially ionized plasmas than when there are no ion-neutral collisions, and the heating efficiency depends on the ratio of the ion-neutral collision frequency to the ion gyrofrequency.

Dong, Chuanfei; 10.1063/1.3555532

2011-01-01T23:59:59.000Z

459

Identification of novel ionizing radiation signaling targets in reconstituted human skin  

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

of novel ionizing radiation signaling targets in reconstituted human skin of novel ionizing radiation signaling targets in reconstituted human skin Feng Yang, Katrina M. Waters, Bobbie-Jo Webb-Robertson, Lye-Meng Markillie, Rachel M. Wirgau, Shawna M. Hengel, Ljiljana Pasa-Tolic, and David L. Stenoien. Pacific Northwest National Laboratory Our focus has been on identifying the early events that occur after low dose ionizing radiation exposure that precede and often regulate downstream events such as altered transcription, protein secretion and epigenetic regulation. Phosphorylation is one of the earliest detectible events that occurs following radiation exposure and plays important roles in multiple biological pathways including DNA damage repair, transcription, apoptosis, and cell cycle progression. Very robust

460

Investigation of non-targeted effects of low dose ionizing radiation on the mammary gland  

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

non-targeted effects of low dose ionizing radiation on the mammary gland non-targeted effects of low dose ionizing radiation on the mammary gland utilizing three-dimensional culture models of mammary cells derived from mouse strains that differ in susceptibility to tumorigenesis Joni D. Mott, Antoine M. Snijders, Alvin Lo, Dinah Levy-Groesser, Bahram Parvin, Andrew J. Wyrobek, Jian-Hua Mao, and Mina J. Bissell Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720 Goal: Within the Lawrence Berkeley National Laboratory's SFA, Project 2, our studies focus on utilizing three dimensional (3D) cell culture models as surrogates for in vivo studies to determine how low doses of ionizing radiation influence mammary gland tissue architecture and how this may relate both to tumor progression and/or adaptive response.

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


461

Low Dose Radiation Research Program: Low Dose Ionizing Radiation-Induced  

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

Low Dose Ionizing Radiation-Induced Effects in Irradiated and Low Dose Ionizing Radiation-Induced Effects in Irradiated and Unirradiated cells: Pathways Analysis in Support of Risk Assessment. Authors: B.E. Lehnert, R. Cary, D. Gadbois, and G. Gupta. Institutions: Bioscience Division, Los Alamos National Laboratory. The scientific literature presents a confusing picture concerning health risks due to low dose ionizing radiation (LDIR), e.g., <1-10 cGy. Some effects of LDIR such as enhanced rates of cell proliferation and the induction of radioadaptation may be benign under some circumstances. Other evidence suggests LDIR can be hazardous and that a threshold for potentially detrimental responses, e.g., increases in intracellular reactive oxygen species (ROS), increases in sister chromatid exchanges (SCE), alterations in gene or protein expression profiles, and increased

462

Controlling double ionization of atoms in an intense bichromatic laser pulse  

SciTech Connect

We consider the classical dynamics of a two-electron system subjected to an intense bichromatic linearly polarized laser pulse. By varying the parameters of the field, such as the phase lag and the relative amplitude between the two colors of the field, we observe several trends from the statistical analysis of a large ensemble of trajectories initially in the ground-state energy of the helium atom: high sensitivity of the sequential double-ionization component, low sensitivity of the intensities where nonsequential double ionization occurs, while the corresponding yields can vary drastically. All these trends hold irrespective of which parameter is varied: the phase lag or the relative amplitude. We rationalize these observations by an analysis of the phase-space structures that drive the dynamics of this system and determine the extent of double ionization. These trends turn out to be mainly regulated by the dynamics of the inner electron.

Kamor, A.; Uzer, T. [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430 (United States); Mauger, F.; Chandre, C. [Centre de Physique Theorique, CNRS, Aix-Marseille Universite, Campus de Luminy, case 907, 13288 Marseille cedex 09 (France)

2011-03-15T23:59:59.000Z

463

Does nitrate deposition following astrophysical ionizing radiation events pose an additional threat to amphibians?  

E-Print Network (OSTI)

It is known that amphibians are especially susceptible to the combination of heightened UVB radiation and increased nitrate concentrations. Various astrophysical events have been suggested as sources of ionizing radiation that could pose a threat to life on Earth, through destruction of the ozone layer and subsequent increase in UVB, followed by deposition of nitrate. In this study, we investigate whether the nitrate deposition following an ionizing event is sufficiently large to cause an additional stress beyond that of the heightened UVB previously considered. We have converted predicted nitrate depositions to concentration values, utilizing data from the New York State Department of Environmental Conservation Acid Rain Monitoring Network web site. Our results show that the increase in nitrate concentration in bodies of water following the most intense ionization event likely in the last billion years would not be sufficient to cause a serious additional stress on amphibian populations and may actually provide some benefit by acting as fertilizer.

Brian C. Thomas; Michelle D. Honeyman

2008-04-22T23:59:59.000Z

464

Amphibian nitrate stress as an additional terrestrial threat from astrophysical ionizing radiation events?  

E-Print Network (OSTI)

As diversity in amphibian species declines, the search for causes has intensified. Work in this area has shown that amphibians are especially susceptible to the combination of heightened UVB radiation and increased nitrate concentrations. Various astrophysical events have been suggested as sources of ionizing radiation that could pose a threat to life on Earth, through destruction of the ozone layer and subsequent increase in UVB, followed by deposition of nitrate. In this study, we investigate whether the nitrate deposition following an ionizing event is sufficiently large to cause an additional stress beyond that of the heightened UVB previously considered. We have converted predicted nitrate depositions to concentration values, utilizing data from the New York State Department of Environmental Conservation Acid Rain Monitoring Network web site. Our results show that the increase in nitrate concentration in bodies of water following the most intense ionization event likely in the last billion years would no...

Thomas, Brian C

2008-01-01T23:59:59.000Z

465

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

Science Conference Proceedings (OSTI)

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.

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)

2011-02-15T23:59:59.000Z

466

Mechanisms Underlying Cellular Responses to Low Doses/Low LET Ionizing Radiation in Primary Haemopoietic Cells.  

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

Mechanisms Underlying Cellular Responses to Low Doses/Low LET Ionizing Radiation Mechanisms Underlying Cellular Responses to Low Doses/Low LET Ionizing Radiation in Primary Haemopoietic Cells. Munira Kadhim 1 , Stefania Militi 1 , Debbie Bowler 1 , Denise Macdonald 1 and Kevin Prise 2 1 Radiation and Genome Stability Unit, MRC, Harwell, Didcot, Oxon, OX11 0RD, UK 2 Gray Cancer Institute ,PO Box 100, Mount Vernon Hospital, Northwood, HA6 2JR, UK Because the human population is genetically heterogeneous, it is important to understand the role that heterogeneity may play in radiation response. Exposure to ionizing radiation can lead to a suite of changes, including increased mutation rate, delayed reproductive cell death, and delayed chromosomal aberrations, all of which are manifestations of the complex genomic instability (GI) phenotype. Following exposure to either high LET

467

Relativistic theory of frequency blue-shift of an intense ionizing laser beam in a plasma  

SciTech Connect

Frequency up-conversion of a laser beam causing gas ionization in a cavity is considered in a fully relativistic fashion. A simple ionization model, based on one-photon and multiphoton processes is used. A Vlasov fully nonlinear and ionization-model independent description is used in calculating the current which drives the wave equation for the electric field. The evolution of the wave frequency and its upshift are contrasted with those obtained in the nonrelativistic limit. It is found that the nonrelativistic treatment overestimates the frequency upshift by a factor more than two. Purely relativistic effects, such as a significant frequency modulation and a respective temporal pulse compression, are observed in the exact case.

Hizanidis, K.; Vomvoridis, J.L. [National Technical Univ. of Athens (Greece); Mendonca, J.T. [Instituto Superior Tecnico, Lisbon (Portugal). Dept. of Physics; Frantzeskakis, D.J. [Univ. of Athens (Greece). Dept. of Physics

1996-04-01T23:59:59.000Z

468

ENERGY DISTRIBUTION OF TWO-ELECTRON IONIZATION OF HELIUM IN AN INTENSE LASER FIELD.  

DOE Green Energy (OSTI)

It is well known that a neutral atom interacting with a strong laser field will ionize at sufficiently high intensity even for photon energies well below the ionization threshold. When the required number of photons becomes very large, this process is best described by the suppression of the Coulomb barrier by the laser's oscillating electric field, allowing the electron to tunnel into the continuum. As the laser intensity is increased, more tightly bound electrons may be successively liberated by this mechanism. Such a sequential multiple ionization, long accepted as a reasonable approach to the formidable problem of a multielectron atom interacting nonperturbatively with an intense electromagnetic field, provides fair estimates of the various charge state appearance intensities while the tunneling rates are in excellent agreement with single ionization yields. However, more accurate measurements revealed systematic and very large deviations from the tunneling rates: near appearance intensity under standard experimental conditions, the observed double ion yield is several orders of magnitude larger than predicted by the sequential rate. It soon became clear that electrons could not be considered as independent and that electron-electron correlation had to be taken into account. Dynamic correlations have been considered in several theories. First qualitatively in the shakeoff model; then empirically through the e-2e cross-section in the quantum/classical three-step model (tunnel ionization, acceleration by the oscillating electric field and e-2e recollision with the ion); recently through the so-called intense field many-body-S-matrix theory and a purely empirical model of collective tunnel ionization. The validity of these ideas has been examined using numerical models. The measurement of total ion yields over a dynamic range exceeding ten orders of magnitude, a major breakthrough made possible by the availability of high-repetition rate lasers at the beginning of the 90's, was for a long time the only quantitative data to confront theory.

LAFON,R.; CHALOUPKA,J.L.; SHEEHY,B.; DIMAURO,L.F.; PAUL,P.M.; AGOSTINI,P.; KULANDER,K.C.

2000-09-24T23:59:59.000Z

469

Advances Toward Inner-Shell Photo-Ionization X-Ray Lasing at 45 (Angstrom)  

Science Conference Proceedings (OSTI)

The inner-shell photo-ionization (ISPI) scheme requires photon energies at least high enough to photo-ionize the K-shell. {approx}286 eV, in the case of carbon. As a consequence of the higher cross-section, the inner-shell are selectively knocked out, leaving a hole state 1s2s{sup 2}2p{sup 2} in the singly charged carbon ion. This generates a population inversion to the radiatively connected state 1s{sup 2}2s{sup 2}2p in C+, leading to gain on the 1s-2p transition at 45 {angstrom}. The resonant character of the lasing transition in the single ionization state intrinsically allows much higher quantum efficiency compared to other schemes. Competing processes that deplete the population inversion include auto-ionization, Auger decay, and in particular collisional ionization of the outer-shell electrons by electrons generated during photo-ionization. These competing processes rapidly quench the gain. Consequently, the pump method must be capable of populating the inversion at a rate faster than the competing processes. This can be achieved by an ultra-fast, high intensity laser that is able to generate an ultra-fast, bright x-ray source. With current advances in the development of high-power, ultra-short pulse lasers it is possible to realize fast x-ray sources based that can deliver powerful pulses of light in the multiple hundred terawatt regime and beyond. They will discuss in greater detail concept, target design and a series of x-ray spectroscopy investigations they have conducted in order to optimize the absorber/x-ray converter--filter package.

Moon, S J; Weber, F A; Celliers, P M; Eder, D C

2002-07-18T23:59:59.000Z

470

Ab initio studies of ionization potentials of hydrated hydroxide and hydronium  

E-Print Network (OSTI)

The ionization potential distributions of hydrated hydroxide and hydronium are computed with many-body approach for electron excitations with configurations generated by {\\it ab initio} molecular dynamics. The experimental features are well reproduced and found to be closely related to the molecular excitations. In the stable configurations, the ionization potential is mainly perturbed by water molecules within the first solvation shell. On the other hand, electron excitation is delocalized on both proton receiving and donating complex during proton transfer, which shifts the excitation energies and broadens the spectra for both hydrated ions.

Swartz, Charles W

2013-01-01T23:59:59.000Z

471

IONIZED GAS IN THE FIRST 10 kpc OF THE INTERSTELLAR GALACTIC HALO: METAL ION FRACTIONS  

SciTech Connect

We present direct measures of the ionization fractions of several sulfur ions in the Galactic warm ionized medium (WIM). We obtained high-resolution ultraviolet absorption-line spectroscopy of post-asymptotic giant branch stars in the globular clusters Messier 3 [(l, b) = (42.{sup 0}2, +78.{sup 0}7), d = 10.2 kpc, and z = 10.0 kpc] and Messier 5 [(l, b) = (3.{sup 0}9, +46.{sup 0}8), d = 7.5 kpc, and z = +5.3 kpc] with the Hubble Space Telescope and Far Ultraviolet Spectroscopic Explorer to measure, or place limits on, the column densities of S I, S II, S III, S IV, S VI, and H I. These clusters also house millisecond pulsars, whose dispersion measures give an electron column density from which we infer the H II column in these directions. We find fractions of S{sup +2} in the WIM for the M 3 and M 5 sight lines x(S{sup +2}) {identical_to} N(S{sup +2})/N(S) = 0.33 {+-} 0.07 and 0.47 {+-} 0.09, respectively, with variations perhaps related to location. With negligible quantities of the higher ionization states, we conclude that S{sup +} and S{sup +2} account for all of the S in the WIM. We extend the methodology to study the ion fractions in the warm and hot ionized gas of the Milky Way, including the high ions Si{sup +3}, C{sup +3}, N{sup +4}, and O{sup +5}. The vast majority of the Galactic ionized gas is warm (T {approx} 10{sup 4} K) and photoionized (the WIM) or very hot (T > 4 Multiplication-Sign 10{sup 5} K) and collisionally ionized. The common tracer of ionized gas beyond the Milky Way, O{sup +5}, traces <1% of the total ionized gas mass of the Milky Way.

Howk, J. Christopher [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Consiglio, S. Michelle, E-mail: jhowk@nd.edu, E-mail: smconsiglio@ucla.edu [Current address: Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA 90095 (United States)

2012-11-10T23:59:59.000Z

472

The WHAM Northern Sky Survey and the Nature of the Warm Ionized Medium in the Galaxy  

E-Print Network (OSTI)

The Wisconsin H-Alpha Mapper (WHAM) has completed a velocity-resolved map of diffuse H-alpha emission of the entire northern sky, providing the first comprehensive picture of both the distribution and kinematics of diffuse ionized gas in the Galaxy. WHAM continues to advance our understanding of the physical conditions of the warm ionized medium through observations of other optical emission lines throughout the Galactic disk and halo. We discuss some highlights from the survey, including an optical window into the inner Galaxy and the relationship between HI and HII in the diffuse ISM.

Madsen, G J

2003-01-01T23:59:59.000Z

473

THE WHAM NORTHERN SKY SURVEY AND THE NATURE OF THE WARM IONIZED MEDIUM IN THE GALAXY  

E-Print Network (OSTI)

The Wisconsin H-Alpha Mapper (WHAM) has completed a velocity-resolved map of diffuse H? emission of the entire northern sky, providing the first comprehensive picture of both the distribution and kinematics of diffuse ionized gas in the Galaxy. WHAM continues to advance our understanding of the physical conditions of the warm ionized medium through observations of other optical emission lines throughout the Galactic disk and halo. We discuss some highlights from the survey, including an optical window into the inner Galaxy and the relationship between H I and H II in the diffuse ISM. 1.

G. J. Madsen

2003-01-01T23:59:59.000Z

474

The WHAM Northern Sky Survey and the Nature of the Warm Ionized Medium in the Galaxy  

E-Print Network (OSTI)

The Wisconsin H-Alpha Mapper (WHAM) has completed a velocity-resolved map of diffuse H-alpha emission of the entire northern sky, providing the first comprehensive picture of both the distribution and kinematics of diffuse ionized gas in the Galaxy. WHAM continues to advance our understanding of the physical conditions of the warm ionized medium through observations of other optical emission lines throughout the Galactic disk and halo. We discuss some highlights from the survey, including an optical window into the inner Galaxy and the relationship between HI and HII in the diffuse ISM.

G. J. Madsen

2003-10-13T23:59:59.000Z

475

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

Science Conference Proceedings (OSTI)

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.

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)

2012-07-11T23:59:59.000Z

476

A 3D Monte Carlo Photoionization Code for Modeling Diffuse Ionized Gas  

E-Print Network (OSTI)

We have developed a three dimensional Monte Carlo photoionization code tailored for the study of Galactic H II regions and the percolation of ionizing photons in diffuse ionized gas. We describe the code, our calculation of photoionization, heating & cooling, and the approximations we have employed for the low density H II regions we wish to study. Our code gives results in agreement with the Lexington H II region benchmarks. We show an example of a 2D shadowed region and point out the very significant effect that diffuse radiation produced by recombinations of helium has on the temperature within the shadow.

Wood, K; Ercolano, B

2004-01-01T23:59:59.000Z

477

Fosmid Cre-LoxP Inverse PCR Paired-End (Fosmid CLIP-PE), a Novel Method for Constructing Fosmid Pair-End Library (Seventh Annual Sequencing, Finishing, Analysis in the Future (SFAF) Meeting 2012)  

SciTech Connect

Ze Peng from DOE JGI presents "Fosmid Cre-LoxP Inverse PCR Paired-End (Fosmid CLIP-PE), a Novel Method for Constructing Fosmid Pair-End Library" at the 7th Annual Sequencing, Finishing, Analysis in the Future (SFAF) Meeting held in June, 2012 in Santa Fe, NM.

Peng, Ze [DOE JGI

2012-06-01T23:59:59.000Z

478

Chemical Ionization Mass Spectrometer (CIMS) Shanhu Lee, Kent State University (http://www.personal.kent.edu/~slee19/)  

E-Print Network (OSTI)

Chemical Ionization Mass Spectrometer (CIMS) Shanhu Lee, Kent State University (http ionization mass spectrometry (PTR-CIMS). A typical CIMS instrument can be constructed from an ion source, an ion molecular reactor, and a quadrupole mass spectrometer. Shown below is schematic diagram of a CIMS

Lee, Shan-Hu

479

A Proposal of Pulse-Pair Doppler Operation on a Spaceborne Cloud-Profiling Radar in the W Band  

Science Conference Proceedings (OSTI)

Pulse-pair Doppler operation is considered for the spaceborne mission. In a formalism, the condition that a measured Doppler velocity on pulse-pair operation corresponds to that on the FFT operation is derived. The coherent coupling effect of the ...

Satoru Kobayashi; Hiroshi Kumagai; Hiroshi Kuroiwa

2002-09-01T23:59:59.000Z

480

An efficient remote user authentication and key agreement protocol for mobile client-server environment from pairings  

Science Conference Proceedings (OSTI)

With the continue evaluation of mobile devices in terms of the capabilities and services, security concerns increase dramatically. To provide secured communication in mobile client-server environment, many user authentication protocols from pairings ... Keywords: Bilinear pairing, ID-based, Key agreement, Mobile device, Mutual authentication, Provable security

Debiao He

2012-08-01T23:59:59.000Z

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


481

Double-plateau in the energy distribution of electrons scattered by ions-pairs in a strong laser field  

E-Print Network (OSTI)

Double-plateau in the energy distribution of electrons scattered by ions-pairs in a strong laser) The energy distribution of electrons scattered from single ions and from pairs of ions in a strong laser solution of the energy distribution for instantaneous Coulomb collisions in three dimensions

Kull, Hans-Jörg

482

Polarization Effects In The Charged Lepton Pair Production By A Neutrino (Antineutrino) In A Magnetic Field  

Science Conference Proceedings (OSTI)

The probability of the process of the charged lepton pair production by a neutrino (an antineutrino) with allowance for the longitudinal and transverse polarizations of the charged leptons in a magnetic field is presented. The dependence of the probability of the process on the spin variables of the charged leptons and on the azimuthal and polar angles of the initial and final neutrinos (antineutrinos) are investigated. It is shown that the probability of the process is sensitive to the spin variables of the charged leptons and to the direction of the neutrino (antineutrino) momentum. It is determined that the neutrino (antineutrino) energy and momentum loss through the production of a charged lepton pair happens asymmetrically.

Huseynov, Vali A. [Department of General and Theoretical Physics, Nakhchivan State University, AZ 7000, Nakhchivan (Azerbaijan); Laboratory of Physical Research, Nakhchivan Division of Azerbaijan National Academy of Sciences, AZ 7000, Nakhchivan (Azerbaijan); Ahmad, Ali S. [Department of General and Theoretical Physics, Nakhchivan State University, AZ 7000, Nakhchivan (Azerbaijan)

2007-06-13T23:59:59.000Z

483

Pion-pair formation and the pion dispersion relation in a hot pion gas  

E-Print Network (OSTI)

The possibility of pion--pair formation in a hot pion gas, based on the bosonic gap equation, is pointed out and discussed in detail. The critical temperature for condensation of pion pairs (Evans--Rashid transition) is determined as a function of the pion density. As for fermions, this phase transition is signaled by the appearance of a pole in the two--particle propagator. In bose systems there exists a second, lower critical temperature, associated with the appearance of the single--particle condensate. Between the two critical temperatures the pion dispersion relation changes from the usual quasiparticle dispersion to a Bogoliubov--like dispersion relation at low momenta. This generalizes the non-relativistic result for an attractive bose gas by Evans et al. Possible consequences for the inclusive pion spectra measured in heavy--ion collisions at ultra--relativistic energies are discussed.

T. Alm; G. Chanfray; P. Schuck; G. Welke

1996-09-13T23:59:59.000Z

484

Bound-Free Electron-Positron Pair Production in Relativistic Heavy-Ion Collisions  

E-Print Network (OSTI)

The bound-free electron-positron pair production is considered for relativistic heavy ion collisions. In particular, cross sections are calculated for the pair production with the simultaneous capture of the electron into the 1s ground state of one of the ions and for energies that are relevant for the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Colliders (LHC). In the framework of perturbation theory, we applied Monte-Carlo integration techniques to compute the lowest-order Feynman diagrams amplitudes by using Darwin wave functions for the bound states of the elec- trons and Sommerfeld-Maue wave functions for the continuum states of the positrons. Calculations were performed especially for the collision of Au + Au at 100 GeV/nucleon and Pb + Pb at 3400 GeV/nucleon.

M. Y. Sengul; M. C. Guclu; S. Fritzsche

2009-07-30T23:59:59.000Z

485

NNLL threshold resummation for top-pair and single-top production  

E-Print Network (OSTI)

I discuss threshold resummation at NNLL accuracy in the standard moment-space approach in perturbative QCD for top-pair and single-top production. For top quark pair production I present new approximate NNLO results for the total cross section and for the top quark transverse momentum and rapidity distributions at 8 TeV LHC energy. I discuss the accuracy of the soft-gluon approximation and show that the NLO and NNLO approximate results from resummation are practically indistinguishable from exact NLO and partial NNLO results. For single top production I present new approximate NNLO results for the total cross sections in all three channels at the LHC and also for the top quark transverse momentum distributions in t-channel production and in top-quark associated production with a W boson. For both ttbar and single-top production the agreement of theoretical results with LHC and Tevatron data is excellent.

Nikolaos Kidonakis

2012-10-29T23:59:59.000Z

486

A photoinduced persistent structural transformation of the special pair of a bacterial reaction center  

SciTech Connect

Structural modification of photosynthetic reaction centers is an important approach for understanding their charge-separation processes. An unprecedented persistent structural transformation of the special pair (dimer) of bacterioclorophyll molecules can be produced by light absorption alone. The nonphotochemical hole-burned spectra for the reaction center of Rhodopeseudomonas viridis show that the phototransformation leads to a red shift of 150 wave numbers for the special pair's lowest energy absorption band, P960, and a comparable blue shift for a state at 850 nanometers, which can now be definitively assigned as being most closely associated with the upper dimer component. Additional insights on excited-state electronic structure include the identification of a new state.

Reddy, N.R.S.; Kolaczkowski, S.V.; Small, G.J. (Iowa State Univ., Ames (United States))

1993-04-02T23:59:59.000Z

487

Rotating-filaments-pairs in a hexagonal superlattice state in dielectric barrier discharge  

SciTech Connect

Rotating-filaments-pairs in a hexagonal superlattice state (HSS) are studied in a dielectric barrier discharge system. The evolution and phase diagrams of HSS are given. The wavelength of HSS and the mean diameter of the two rotating filaments all decrease with the increase of applied voltage. The instantaneous orientations of rotating-filaments-pairs are equal probability approximately. There is a larger peak and a smaller one in both the probability density functions of the rotation speed ({omega}) of rotating filaments and that of the distance (D) between two rotating filaments. According to the fitting curves of ln{omega}{sup 2} vs. lnD, {omega}{sup 2} is inversely proportional to D{sup 7}. The rotation of filaments is discussed theoretically by the force among surface charges.

Dong Lifang; Yang Yujie; Li Ben; Fan Weili; Song Qian [College of Physics Science and Technology, Hebei University, Baoding 071002 (China) and Hebei Key Laboratory of Optic-electronic Information Materials, Baoding 071002 (China)

2011-12-15T23:59:59.000Z

488

Implosion and explosion of electrostatic cylindrical and spherical shocks in asymmetric pair-ion plasmas  

SciTech Connect

Nonlinear electrostatic shock waves are studied in unmagnetized, dissipative pair-ion plasmas. The dissipation in the system is taken into account by considering the effect of kinematic viscosity of both positive and negative ions in plasmas. The system of fluid equations for asymmetric pair-ion plasma is reduced to Korteweg-deVries-Burgers equation in the limit of small amplitude perturbation. It is observed that the system under consideration admits rarefactive shocks. Keeping in view the practical applications, the nonlinear propagation of both the exploding and imploding shocks is investigated and the differences are expounded in detail. The present study may have relevance in the study of the formation of electrostatic shocks in laser-induced implosion devices, star formation, supernovae explosion, etc.

Masood, W. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad 54000 (Pakistan); National Centre for Physics (NCP), Shahdara Valley Road, Islamabad 44000 (Pakistan); Rizvi, H. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad 54000 (Pakistan)

2011-04-15T23:59:59.000Z

489

Linear and nonlinear coupled drift and ion acoustic waves in collisional pair ion-electron magnetoplasma  

SciTech Connect

Linear and nonlinear coupled electrostatic drift and ion acoustic waves are studied in inhomogeneous, collisional pair ion-electron plasma. The Korteweg-de Vries-Burgers (KdVB) equation for a medium where both dispersion and dissipation are present is derived. An attempt is made to obtain exact solution of KdVB equation by using modified tanh-coth method for arbitrary velocity of nonlinear drift wave. Another exact solution for KdVB is obtained, which gives a structure of shock wave. Korteweg-de Vries (KdV) and Burgers equations are derived in limiting cases with solitary and monotonic shock solutions, respectively. Effects of species density, magnetic field, obliqueness, and the acoustic to drift velocity ratio on the solitary and shock solutions are investigated. The results discussed are useful in understanding of low frequency electrostatic waves at laboratory pair ion plasmas.

Mushtaq, A. [Theoretical Plasma Physics Division, Pakistan Institute of Nuclear Science and Technology (PINSTECH), Nilore, Islamabad 45660 (Pakistan); School of Physics, University of Sydney, New South Wales 2006 (Australia); Saeed, R.; Haque, Q. [Theoretical Plasma Physics Division, Pakistan Institute of Nuclear Science and Technology (PINSTECH), Nilore, Islamabad 45660 (Pakistan)

2011-04-15T23:59:59.000Z

490

Effects of crystal length on the angular spectrum of spontaneous parametric downconversion photon pairs  

E-Print Network (OSTI)

We present a theoretical and experimental analysis of the joint effects of the transverse electric field distribution and of the nonlinear crystal characteristics on the properties of photon pairs generated by spontaneous parametric downconversion (SPDC). While it is known that for a sufficiently short crystal the pump electric field distribution fully determines the joint signal-idler properties, for longer crystals the nonlinear crystal properties also play an important role. In this paper we present experimental measurements of the angular spectrum (AS) and of the conditional angular spectrum (CAS) of photon pairs produced by spontaneous parametric downconversion (SPDC), carried out through spatially-resolved photon counting. In our experiment we control whether or not the source operates in the short-crystal regime through the degree of pump focusing, and explicitly show how the AS and CAS measurements differ in these two regimes. Our theory provides an understanding of the boundary between these two regimes and also predicts the corresponding differing behaviors.

Roberto Ramirez-Alarcon; Hector Cruz-Ramirez; Alfred B. U'Ren

2013-06-20T23:59:59.000Z

491

Search for Higgs decays to tau lepton pairs at the Tevatron  

E-Print Network (OSTI)

We present a search for neutral supersymmetric Higgs bosons decaying to tau+tau- pairs produced in ppbar collisions at sqrt{s}=1.96 TeV. The data have been collected with the CDF II and D0 detectors at the Tevatron collider at Fermilab (1 fb^-1 of integrated luminosity per experiment). No significant excess above the standard model backgrounds is observed. We set exclusion limits on the Higgs production cross-section times the branching fraction of its decay to tau+tau- pairs for Higgs masses in the range from 90 to 250 GeV/c^2. We also set exclusion limits on MSSM parameters m_A and tan_beta in several benchmark scenarios.

I. Kravchenko; for the CDF; D0 Collaborations

2007-10-26T23:59:59.000Z

492

Search for the standard model Higgs boson in tau lepton pair final states  

Science Conference Proceedings (OSTI)

We present a search for the standard model Higgs boson in final states with an electron or muon and a hadronically decaying tau lepton in association with zero, one, or two or more jets using data corresponding to an integrated luminosity of up to 7.3 fb{sup -1} collected with the D0 detector at the Fermilab Tevatron collider. The analysis is sensitive to Higgs boson production via gluon gluon fusion, associated vector boson production, and vector boson fusion, and to Higgs boson decays to tau lepton pairs or W boson pairs. Observed (expected) limits are set on the ratio of 95% C.L. upper limits on the cross section times branching ratio, relative to those predicted by the Standard Model, of 14 (22) at a Higgs boson mass of 115 GeV and 7.7 (6.8) at 165 GeV.

Abazov, V.M.

2012-03-01T23:59:59.000Z

493

Effects of crystal length on the angular spectrum of spontaneous parametric downconversion photon pairs  

E-Print Network (OSTI)

We present a theoretical and experimental analysis of the joint effects of the transverse electric field distribution and of the nonlinear crystal characteristics on the properties of photon pairs generated by spontaneous parametric downconversion (SPDC). While it is known that for a sufficiently short crystal the pump electric field distribution fully determines the joint signal-idler properties, for longer crystals the nonlinear crystal properties also play an important role. In this paper we present experimental measurements of the angular spectrum (AS) and of the conditional angular spectrum (CAS) of photon pairs produced by spontaneous parametric downconversion (SPDC), carried out through spatially-resolved photon counting. In our experiment we control whether or not the source operates in the short-crystal regime through the degree of pump focusing, and explicitly show how the AS and CAS measurements differ in these two regimes. Our theory provides an understanding of the boundary between these two regi...

Ramirez-Alarcon, Roberto; U'Ren, Alfred B

2013-01-01T23:59:59.000Z

494

Spatial correlation of photon pairs produced in spontaneous parametric down-conversion  

SciTech Connect

We report the observation of spatial biphoton correlation in spontaneous parametric down conversion. The optical bench includes a type-I BBO crystal of effective length 2 mm, pumped by a 100 mW violet laser diode centered at 405.38 nm. Photon pairs are created with degenerate wavelength {approx_equal}810.76 nm. Once the horizontal counting rates have been measured, a simple geometrical recipe is shown to be useful in calculating bounds for the width of vertical counting rates. The spatial correlation between idler and signal photons is illustrated with a coincidence distribution of the coordinate pair (x{sub s},x{sub i}), with x{sub i,s} the idler (signal) detector position in horizontal scan.

Procopio, L. M. [Departamento de Fisica, Cinvestav, A.P. 14-740, Mexico D.F. 07000 (Mexico); Rosas-Ortiz, O. [Departamento de Fisica, Cinvestav, A.P. 14-740, Mexico D.F. 07000 (Mexico); Instituto de Fisica, Universidad Nacional Autonoma de Mexico, A.P. 20-364, Mexico D.F. 01000 (Mexico); Velazquez, V. [Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, A.P. 20-364, Mexico D.F. 04510 (Mexico)