Optimization of the Configuration of Pixilated Detectors Based on the Sgabbib-Nyquist Theory for the X-ray Spectroscopy of Hot Tokamak Plasmas (open access)

Optimization of the Configuration of Pixilated Detectors Based on the Sgabbib-Nyquist Theory for the X-ray Spectroscopy of Hot Tokamak Plasmas

This paper describes an optimization of the detector configuration, based on the Shannon-Nyquist theory, for two major x-ray diagnostic systems on tokamaks and stellarators: x-ray imaging crystal spectrometers and x-ray pinhole cameras. Typically, the spectral data recorded with pixilated detectors are oversampled, meaning that the same spectral information could be obtained using fewer pixels. Using experimental data from Alcator C-Mod, we quantify the degree of oversampling and propose alternate uses for the redundant pixels for additional diagnostic applications.
Date: August 9, 2012
Creator: : E. Wang, P. Beiersdorfer, M. Bitter, L.F. Delgado-Apricio, K.W. Hill and N. Pablant
System: The UNT Digital Library
A Model-Independent Search for the decay B->l nu gamma (open access)

A Model-Independent Search for the decay B->l nu gamma

The authors present a search for the radiative leptonic decay B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}}{gamma}, where {ell} = e, {mu}, using a data sample of 465 million B{bar B} pairs collected by the BABAR experiment. In this analysis, they fully reconstruct the hadronic decay of one of the B mesons in {Upsilon}(4S) {yields} B{sup +}B{sup -} decays, then search for evidence of B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}}{gamma} in the rest of the event. They observe no significant evidence of signal decays and report model-independent branching fraction upper limits of {Beta}(B{sup +} {yields} e{sup +}{nu}{sub e}{gamma}) < 17 x 10{sup -6}, {Beta}(B{sup +} {yields} {mu}{sup +}{nu}{sub {mu}}{gamma}) < 24 x 10{sup -6}, and {Beta}(B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}}{gamma}) < 15.6 x 10{sup -6} ({ell} = e or {mu}), all at the 90% confidence level.
Date: October 9, 2012
Creator: Aubert, Bernard; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E.; Prudent, X. et al.
System: The UNT Digital Library
Developing of superconducting RF guns at BNL (open access)

Developing of superconducting RF guns at BNL

N/A
Date: September 9, 2012
Creator: Belomestnykh, S.; Altinbas, Z.; Ben-Zvi, Ilan; Boulware, C. H.; Brutus, J. C.; Burrill, A. et al.
System: The UNT Digital Library
Superconducting RF linac for eRHIC (open access)

Superconducting RF linac for eRHIC

N/A
Date: September 9, 2012
Creator: Belomestnykh, S.; Ben-Zvi, Ilan; Brutus, J. C.; Hahn, H.; Kayran, D.; Litvinenko, V. et al.
System: The UNT Digital Library
The high-current ERL at BNL (open access)

The high-current ERL at BNL

N/A
Date: September 9, 2012
Creator: Ben-Zvi, Ilan
System: The UNT Digital Library
INTERCOMPARISON OF 14C ANALYSIS OF CARBONACEOUS AEROSOLS: EXERCISE 2009 (open access)

INTERCOMPARISON OF 14C ANALYSIS OF CARBONACEOUS AEROSOLS: EXERCISE 2009

None
Date: November 9, 2012
Creator: Bench, G
System: The UNT Digital Library
Cavity Beam Position Monitor System for ATF2 (open access)

Cavity Beam Position Monitor System for ATF2

The Accelerator Test Facility 2 (ATF2) in KEK, Japan, is a prototype scaled demonstrator system for the final focus required for a future high energy lepton linear collider. The ATF2 beam-line is instrumented with a total of 38 C and S band resonant cavity beam position monitors (CBPM) with associated mixer electronics and digitizers. The current status of the BPM system is described, with a focus on operational techniques and performance. The ATF2 C-band system is performing well, with individual CBPM resolution approaching or at the design resolution of 50 nm. The changes in the CBPM calibration observed over three weeks can probably be attributed to thermal effects on the mixer electronics systems. The CW calibration tone power will be upgraded to monitor changes in the electronics gain and phase. The four S-band CBPMs are still to be investigated, the main problem associated with these cavities is a large cross coupling between the x and y ports. This combined with the large design dispersion in that degion makes the digital signal processing difficult, although various techniques exist to determine the cavity parameters and use these coupled signals for beam position determination.
Date: July 9, 2012
Creator: Boogert, Stewart; /Oxford U., JAI; Boorman, Gary; /Oxford U., JAI; Swinson, Christina; /Oxford U., JAI et al.
System: The UNT Digital Library
Novel Perspectives for Hadron Physics (open access)

Novel Perspectives for Hadron Physics

I discuss several novel and unexpected aspects of quantum chromodynamics. These include: (a) the nonperturbative origin of intrinsic strange, charm and bottom quarks in the nucleon at large x; the breakdown of pQCD factorization theorems due to the lensing effects of initial- and final-state interactions; (b) important corrections to pQCD scaling for inclusive reactions due to processes in which hadrons are created at high transverse momentum directly in the hard processes and their relation to the baryon anomaly in high-centrality heavy-ion collisions; and (c) the nonuniversality of quark distributions in nuclei. I also discuss some novel theoretical perspectives in QCD: (a) light-front holography - a relativistic color-confining first approximation to QCD based on the AdS/CFT correspondence principle; (b) the principle of maximum conformality - a method which determines the renormalization scale at finite order in perturbation theory yielding scheme independent results; (c) the replacement of quark and gluon vacuum condensates by 'in-hadron condensates' and how this helps to resolve the conflict between QCD vacuum and the cosmological constant.
Date: March 9, 2012
Creator: Brodsky, Stanley J.
System: The UNT Digital Library
S-wave scattering of strangeness -3 baryons (open access)

S-wave scattering of strangeness -3 baryons

None
Date: January 9, 2012
Creator: Buchoff, M; Luu, T & Wasem, J
System: The UNT Digital Library
Future Synchrotron Light Sources Based on Ultimate Storage Rings (open access)

Future Synchrotron Light Sources Based on Ultimate Storage Rings

The main purpose of this talk is to describe how far one might push the state of the art in storage ring design. The talk will start with an overview of the latest developments and advances in the design of synchrotron light sources based on the concept of an 'ultimate' storage ring. The review will establish how bright a ring based light source might be, where the frontier of technological challenges are, and what the limits of accelerator physics are. Emphasis will be given to possible improvements in accelerator design and developments in technology toward the goal of achieving an ultimate storage ring. An ultimate storage ring (USR), defined as an electron ring-based light source having an emittance in both transverse planes at the diffraction limit for the range of X-ray wavelengths of interest for a scientific community, would provide very high brightness photons having high transverse coherence that would extend the capabilities of X-ray imaging and probe techniques beyond today's performance. It would be a cost-effective, high-coherence 4th generation light source, competitive with one based on energy recovery linac (ERL) technology, serving a large number of users studying material, chemical, and biological sciences. Furthermore, because of the experience accumulated …
Date: April 9, 2012
Creator: Cai, Yunhai
System: The UNT Digital Library
Moduli Stabilization and the Holographic RG for AdS and dS (open access)

Moduli Stabilization and the Holographic RG for AdS and dS

None
Date: November 9, 2012
Creator: Dong, Xi; Horn, Bart; Silverstein, Eva & Torroba, Gonzalo
System: The UNT Digital Library
Laser-induced gas plasma etching of fused silica under ambient conditions (open access)

Laser-induced gas plasma etching of fused silica under ambient conditions

None
Date: November 9, 2012
Creator: Elhadj, S.; Guss, G.; Matthews, M. & Bass, I.
System: The UNT Digital Library
Beam Measurements at LCLS (open access)

Beam Measurements at LCLS

None
Date: May 9, 2012
Creator: Frisch, J.; Akre, R.; Decker, F. J.; Ding, Y.; Dowell, D.; Emma, P. et al.
System: The UNT Digital Library
Performance Modeling of Algebraic Multigrid on Blue Gene/Q: Lessons Learned (open access)

Performance Modeling of Algebraic Multigrid on Blue Gene/Q: Lessons Learned

None
Date: September 9, 2012
Creator: Gahvari, H.; Gropp, W.; Jordan, K. E.; Schulz, M. & Yang, U. M.
System: The UNT Digital Library
2012 BATTERIES GORDON RESEARCH CONFERENCE, MARCH 4-9, 2012 (open access)

2012 BATTERIES GORDON RESEARCH CONFERENCE, MARCH 4-9, 2012

The Gordon Research Conference on BATTERIES was held at Four Points Sheraton / Holiday Inn Express, Ventura, California, March 4-9, 2012. The Conference was well-attended with 176 participants. Gordon Research Conferences does not permit publication of meeting proceedings.
Date: March 9, 2012
Creator: Harris, Stephen
System: The UNT Digital Library
DETERMINATION OF THE DISTRIBUTION AND INVENTORY OF RADIONUCLIDES WITHIN A SAVANNAH RIVER SITE WATERWAY (open access)

DETERMINATION OF THE DISTRIBUTION AND INVENTORY OF RADIONUCLIDES WITHIN A SAVANNAH RIVER SITE WATERWAY

An investigation was conducted to evaluate the radionuclide inventory within the Lower Three Runs (LTR) Integrator Operable Unit (IOU) at the U.S. Department of Energy’s (DOE’s) Savannah River Site (SRS). The scope of this effort included the analysis of previously existing sampling and analysis data as well as additional streambed and floodplain sampling and analysis data acquired to delineate horizontal and vertical distributions of the radionuclide as part of the ongoing SRS environmental restoration program, and specifically for the LTR IOU program. While cesium-137 (Cs-137) is the most significant and abundant radionuclide associated with the LTR IOU it is not the only radionuclide, hence the scope included evaluating all radionuclides present and includes an evaluation of inventory uncertainty for use in sensitivity and uncertainty analyses. The scope involved evaluation of the radionuclide inventory in the P-Reactor and RReactor cooling water effluent canal systems, PAR Pond (including Pond C) and the floodplain and stream sediment sections of LTR between the PAR Pond Dam and the Savannah River. The approach taken was to examine all of the available Sediment and Sediment/Soil analysis data available along the P- and R-Reactor cooling water re-circulation canal system, the ponds situated along those canal reaches and …
Date: November 9, 2012
Creator: Hiergesell, R. & Phifer, M.
System: The UNT Digital Library
2011 Raditation & Climate Gordon Research Conference (July 10-15 2011- Colby College, Waterville, Maine) (open access)

2011 Raditation & Climate Gordon Research Conference (July 10-15 2011- Colby College, Waterville, Maine)

The 2011 Gordon Research Conference on Radiation and Climate will present cutting-edge research on outstanding issues in climate change, particularly those in which the interactions between clouds, aerosols, and precipitation play a major role. The Conference will feature a broad range of topics, including grand challenges in atmospheric radiation and climate, cloud and water vapor feedbacks, aerosol-cloud-precipitation-climate interactions across scales, new approaches for remote sensing and in-situ observations of clouds, aerosols and precipitation, and multi-scale modeling challenges. The invited speakers will present the most important recent advances and future challenges in these areas. The Conference will bring together a collection of leading investigators who are at the forefront of their field, and will provide opportunities for scientists, especially junior scientists and graduate students, to present their work in poster format and exchange ideas with leaders in the field. The collegial atmosphere of this Conference, with programmed discussion sessions as well as opportunities for informal gatherings in the afternoons and evenings, provides an avenue for scientists from different disciplines to brainstorm and promotes cross-disciplinary collaborations in the various research areas represented.
Date: February 9, 2012
Creator: Hoggblom, Prof. Max
System: The UNT Digital Library
Uncovering Selective Excitations Using the Resonant Profile of Indirect Inelastic X-ray Scattering in Correlated Materials: Observing Two-magnon Scattering and Relation to the Dynamical Structure Factor (open access)

Uncovering Selective Excitations Using the Resonant Profile of Indirect Inelastic X-ray Scattering in Correlated Materials: Observing Two-magnon Scattering and Relation to the Dynamical Structure Factor

None
Date: October 9, 2012
Creator: Jia, C. J.; Chen, C. C.; Sorini, A. P.; Moritz, B. & Devereaux, T. P.
System: The UNT Digital Library
Quarkonium Physics at a Fixed-Target Experiment Using the LHC Beams (open access)

Quarkonium Physics at a Fixed-Target Experiment Using the LHC Beams

We outline the many quarkonium-physics opportunities offered by a multi-purpose fixed-target experiment using the p and Pb LHC beams extracted by a bent crystal. This provides an integrated luminosity of 0.5 fb{sup -1} per year on a typical 1cm-long target. Such an extraction mode does not alter the performance of the collider experiments at the LHC. With such a high luminosity, one can analyse quarkonium production in great details in pp, pd and pA collisions at {radical}s{sub NN} {approx_equal} 115 GeV and at {radical}s{sub NN} {approx_equal} 72 GeV in PbA collisions. In a typical pp (pA) run, the obtained quarkonium yields per unit of rapidity are 2-3 orders of magnitude larger than those expected at RHIC and about respectively 10 (70) times larger than for ALICE. In PbA, they are comparable. By instrumenting the target-rapidity region, the large negative-x{sub F} domain can be accessed for the first time, greatly extending previous measurements by Hera-B and E866. Such analyses should help resolving the quarkonium-production controversies and clear the way for gluon PDF extraction via quarkonium studies. The nuclear target-species versatility provides a unique opportunity to study nuclear matter and the features of the hot and dense matter formed in PbA collisions. …
Date: April 9, 2012
Creator: Lansberg, J. P.; Brodsky, S.J.; Fleuret, F. & Hadjidakis, C.
System: The UNT Digital Library
Toward fully self-consistent simulation of the interaction of E-Clouds and beams with WARP-POSINST (open access)

Toward fully self-consistent simulation of the interaction of E-Clouds and beams with WARP-POSINST

To predict the evolution of electron clouds and their effect on the beam, the high energy physics community has relied so far on the complementary use of 'buildup' and 'single/multi-bunch instability' reduced descriptions. The former describes the evolution of electron clouds at a given location in the ring, or 'station', under the influence of prescribed beams and external fields [1], while the latter (sometimes also referred as the 'quasi-static' approximation [2]) follows the interaction between the beams and the electron clouds around the accelerator with prescribed initial distributions of electrons, assumed to be concentrated at a number of discrete 'stations' around the ring. Examples of single bunch instability codes include HEADTAIL [3], QuickPIC [4, 5], and PEHTS [6]. By contrast, a fully self-consistent approach, in which both the electron cloud and beam distributions evolve simultaneously under their mutual influence without any restriction on their relative motion, is required for modeling the interaction of high-intensity beams with electron clouds for heavy-ion beam-driven fusion and warm-dense matter science. This community has relied on the use of Particle-In-Cell (PIC) methods through the development and use of the WARP-POSINST code suite [1, 7, 8]. The development of novel numerical techniques (including adaptive mesh refinement, …
Date: April 9, 2012
Creator: Lawrence Livermore National Laboratory
System: The UNT Digital Library
Evidence for an excess of B to D(*) Tau Nu decays (open access)

Evidence for an excess of B to D(*) Tau Nu decays

Based on the full BABAR data sample, we report improved measurements of the ratios R(D{sup (*)}) = {Beta}({bar B} {yields} D{sup (*)} {tau}{sup -}{bar {nu}}{sub {tau}})/{Beta}({bar B} {yields} D{sup (*)} {ell}{sup -}{bar {nu}}{sub {ell}}), where {ell} is either e or {mu}. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure R(D) = 0.440 {+-} 0.058 {+-} 0.042 and R(D*) = 0.332 {+-} 0.024 {+-} 0.018, which exceed the Standard Model expectations by 2.0{sigma} and 2.7{sigma}, respectively. Taken together, our results disagree with these expectations at the 3.4{sigma} level. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model. We also report the observation of the decay {bar B} {yields} D{tau}{sup -} {bar {nu}}{sub {tau}}, with a significance of 6.8{sigma}.
Date: October 9, 2012
Creator: Lees, J. P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.
System: The UNT Digital Library
Model-Independent Results for the Decay B \to L Nu(L) Gamma at BaBar (open access)

Model-Independent Results for the Decay B \to L Nu(L) Gamma at BaBar

We present a search for the radiative leptonic decays B{sub +} {yields} e{sup +} {nu}{sub e}{gamma} and B{sup +} {yields} {mu}{sup +}{nu}{sub {mu}}{gamma} using data collected by the BABAR detector at the PEP-II B factory. We fully reconstruct the hadronic decay of one of the B mesons in {Upsilon}(4S) {yields} B{sup +}B{sup -} and then search for evidence of the signal decay within the rest of the event. This method provides clean kinematic information on the signal's missing energy and high momentum photon and lepton, and allows for a model-independent analysis of this decay. Using a data sample of 465 million B-meson pairs, we obtain sensitivity to branching fractions of the same order as predicted by the Standard Model. We report a model-independent branching fraction upper limit of {Beta}(B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}}{gamma}) < 15.6 x 10{sup -6} ({ell} = e or {mu}) at the 90% confidence level.
Date: April 9, 2012
Creator: Lindemann, D. M.
System: The UNT Digital Library
Lepton-Flavor-Violating Tau Decays at BaBar (open access)

Lepton-Flavor-Violating Tau Decays at BaBar

We present the most recent searches for lepton-flavor-violating (LFV) {tau} decays in BABAR. We find no evidence of {tau} decaying to three charged leptons or to a charged lepton and a neutral meson (K{sub S}{sup 0}, {rho}, {phi}, K*{sup 0}, {bar K}*{sup 0}), and set upper limits on the corresponding branching fractions (BF) between 1.8 and 19 x 10{sup -8} at 90% confidence level (CL).
Date: April 9, 2012
Creator: Marchiori, G. & /Paris, LPTHE
System: The UNT Digital Library