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A High Repetition Rate VUV-Soft X-Ray FEL Concept (open access)

A High Repetition Rate VUV-Soft X-Ray FEL Concept

We report on design studies for a seeded FEL light source that is responsive to the scientific needs of the future. The FEL process increases radiation flux by several orders of magnitude above existing incoherent sources, and offers the additional enhancements attainable by optical manipulations of the electron beam: control of the temporal duration and bandwidth of the coherent output, reduced gain length in the FEL, utilization of harmonics to attain shorter wavelengths, and precise synchronization of the x-ray pulse with seed laser systems. We describe an FEL facility concept based on a high repetition rate RF photocathode gun, that would allow simultaneous operation of multiple independent FEL's, each producing high average brightness, tunable over the VUV-soft x-ray range, and each with individual performance characteristics determined by the configuration of the FEL. SASE, enhanced-SASE (ESASE), seeded, harmonic generation, and other configurations making use of optical manipulations of the electron beam may be employed, providing a wide range of photon beam properties to meet varied user demands.
Date: June 24, 2007
Creator: Corlett, J.; Byrd, J.; Fawley, W. M.; Gullans, M.; Li, D.; Lidia, S. M. et al.
System: The UNT Digital Library
Energy dependence of jet transport parameter and parton saturationin quark-gluon plasma (open access)

Energy dependence of jet transport parameter and parton saturationin quark-gluon plasma

We study the evolution and saturation of the gluondistribution function in the quark-gluon plasma as probed by apropagating parton and its effect on the computation of jet quenching ortransport parameter $\hat q $. For thermal partons, the saturation scale$Q2_s$ is found to be proportional to the Debye screening mass $\mu_D2$.For hard probes, evolution at small $x=Q2_s/6ET$ leads to jet energydependence of hat q. We study this dependence for both a conformal gaugetheory in weak and strong coupling limit and for (pure gluon) QCD. Theenergy dependence can be used to extract the shear viscosity $\eta$ ofthe medium since $\eta$ can be related to the transport parameter forthermal partons in a transport description. We also derive upper boundson the transport parameter for both energetic and thermal partons. Thelater leads to a lower bound on shear viscosity-to-entropy density ratiowhich is consistent with the conjectured lower bound $\eta/s\geq 1/4\pi$.Implications on the study of jet quenching at RHIC and LHC and the bulkproperties of the dense matter are discussed.
Date: June 24, 2007
Creator: Casalderrey-Solana, Jorge & Wang, Xin-Nian
System: The UNT Digital Library
The Next Generation Air Particle Detectors for the United States Navy (open access)

The Next Generation Air Particle Detectors for the United States Navy

Design and testing of the United States Navy’s next generation air particle detector (NGAPD) is presently underway. The NGAPD is intended for use in nuclear applications for the United States Navy and is being designed to detect airborne Co-60 with a reduction in false alarms and improved ease of use. Features being developed include gamma compensation, low maintenance, commercial off-the-shelf electronics, and spectrum simulation for quality assurance and functional testing applications. By supplying a spectrum simulator, the radon stripping algorithm can be running when a simulated anthropogenic source spectrum (e.g., from Co-60 or transuranics) is superimposed on the radon progeny spectrum. This will allow alarm levels to be tested when the air flow is running and the radon stripping algorithm is providing the instrument response output. Modern units evaluate source spectra with the air flow off and the radon spectrum absent thereby not testing the true system performance which comes out of the radon stripping algorithm. Testing results of the preliminary prototype show promise along with computer simulations of source spectra. Primary testing results taken to date include gamma compensation, thermal insults, vibration and spectrum simulation.
Date: June 24, 2007
Creator: Hayes, Robert & Marianno, Craig
System: The UNT Digital Library
Progress in Finite Temperature Lattice Qcd. (open access)

Progress in Finite Temperature Lattice Qcd.

I review recent progress in finite temperature lattice calculations, including the determination of the transition temperature, equation of state, screening of static quarks and meson spectral functions.
Date: June 24, 2007
Creator: Petreczky, P.
System: The UNT Digital Library
Updating the NRC Standard Review Plan - Chapter 8 - Electrical Systems (open access)

Updating the NRC Standard Review Plan - Chapter 8 - Electrical Systems

The Standard Review Plan (SRP) (Reference 2), provides guidance to the regulatory staff of the Nuclear Regulatory Commission (NRC) on performing their safety reviews of applications to construct or operate nuclear power plants, and applications to approve standard designs and sites for nuclear power plants. Chapter 8 of the SRP provides guidance related to the review of station electrical distribution systems described by the applicant in its Design Control Document (DCD) or Safety Analysis Report (SAR). As part of the 2006-2007 SAR update, all sections in this Chapter (8.1, 8.2, 8.3.1, 8.3.2, Appendix 8A, and Appendix 8B) were revised to incorporate new analyses, design approaches, and the lessons learned from the review of the AP 1000 design certification and to assure consistency with the draft Regulatory Guide DG-1145, ''Combined License Applications for Nuclear Power Plants (LWR Edition)''.
Date: June 24, 2007
Creator: Sullivan, K.
System: The UNT Digital Library
Rad-hard Luminosity Monitoring for the LHC (open access)

Rad-hard Luminosity Monitoring for the LHC

Luminosity measurements at the high luminosity points of the LHC are very challenging due to the extremely high radiation levels in the order of 180 MGy/yr. They have designed an ionization chamber that uses a flowing inorganic gas mixture and a combination of metals and ceramics. With such a choice, an additional challenge is achieving the necessary speed to be able to resolve bunch-by-bunch luminosity data. They present the design, analysis and experimental results of the early demonstration tests of this device.
Date: June 24, 2007
Creator: Beche, J. F.; Byrd, J. M.; Chow, K.; Denes, P.; Ghiorso, W.; Matis, H. S. et al.
System: The UNT Digital Library