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Electron Beam Ion Source Preinjector Project (EBIS) Conceptual Design Report.

Description: This report describes a new heavy ion pre-injector for the Relativistic Heavy Ion Collider (RHIC) based on a high charge state Electron Beam Ion Source (EBIS), a Radio Frequency Quadrupole (RFQ) accelerator, and a short Linear accelerator (Linac). The highly successful development of an EBIS at Brookhaven National Laboratory (BNL) now makes it possible to replace the present pre-injector that is based on an electrostatic Tandem with a reliable, low maintenance Linac-based pre-injector. Linac-ba… more
Date: September 1, 2005
Creator: Alessi, J.; Barton, D.; Beebe, E.; Gassner, D.; Grandinetti, R.; Hseuh, H. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The LCLS Gas Attenuator Revisited

Description: In the report ''X-ray attenuation cell'' [1] a preliminary analysis of the gas attenuator for the Linac Coherent Light Source (LCLS) was presented. This analysis was carried out for extremely stringent set of specifications. In particular, a very large diameter for the unobstructed beam was set (1 cm) to accommodate the spontaneous radiation; the attenuator was supposed to cover the whole range of energies of the coherent radiation, from 800 eV to 8000 eV; the maximum attenuation was set at the… more
Date: June 7, 2005
Creator: Ryutov, D
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Spectroscopy of Argon Excited in an Electron Beam Ion Trap

Description: Argon is one of the gases best investigated and most widely used in plasma discharge devices for a multitude of applications that range from wavelength reference standards to controlled fusion experiments. Reviewing atomic physics and spectroscopic problems in various ionization stages of Ar, the past use and future options of employing an electron beam ion trap (EBIT) for better and more complete Ar data in the x-ray, EUV and visible spectral ranges are discussed.
Date: April 18, 2005
Creator: Trabert, E
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

General computational spectroscopic framework applied to Z-pinch dynamic hohlraum K-shell argon spectra

Description: We describe a general computational spectroscopic framework for interpreting observed spectra. The framework compares synthetic spectra with measured spectra, then optimizes the agreement using the Dakota toolkit to minimize a merit function that incorporates established spectroscopic techniques. We generate synthetic spectra using the self-consistent nonlocal thermodynamic equilibrium atomic kinetics and radiative transfer code Cretin, relativistic atomic structure and cross section data from … more
Date: January 10, 2005
Creator: Adams, M L; Sinars, D B & Scott, H A
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A Rapid Compression Machine Modelling Study of the Heptane Isomers

Description: Previously we have reported on the combustion behavior of all nine isomers of heptane in a rapid compression machine (RCM) with stoichiometric fuel and ''air'' mixtures at a compressed gas pressure of 15 atm. The dependence of autoignition delay times on molecular structure was illustrated. Here, we report some additional experimental work that was performed in order to address unusual results regarding significant differences in the ignition delay times recorded at the same fuel and oxygen com… more
Date: May 10, 2005
Creator: Silke, E J; Curran, H J; Simmie, J M; Pitz, W J & Westbrook, C K
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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High Transverse Momentum Direct Photon Production at Fermilab Fixed-Target Energies

Description: This thesis describes a study of the production of high transverse momentum direct photons and {pi}{sup 0} mesons by proton beams at 530 and 800 GeV/c and {pi}{sup -} beams at 515 GeV/c incident on beryllium, copper, and liquid hydrogen targets. The data were collected by Fermilab experiment E706 during the 1990 and 1991-92 fixed target runs. The apparatus included a large, finely segmented lead and liquid argon electromagnetic calorimeter and a charged particle spectrometer featuring silicon s… more
Date: May 1, 2005
Creator: Apanasevich, Leonard
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

Quantum Efficiency and Topography of Heated and Plasma-Cleaned Copper Photocathode Surfaces

Description: We present measurements of photoemission quantum efficiency (QE) for copper photocathodes heated and cleaned by low energy argon and hydrogen ion plasma. The QE and surface roughness parameters were measured before and after processing and surface chemical composition was tracked in-situ with x-ray photoelectron spectroscopy (XPS). Thermal annealing at 230 C was sufficient to improve the QE by 3-4 orders of magnitude, depending on the initial QE. Exposure to residual gas slowly reduced the QE b… more
Date: August 4, 2005
Creator: Palmer, Dennis T.; Kirby, R. E. & King, F. K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A large liquid argon time projection chamber for long-baseline, off-axis neutrino oscillation physics with the NuMI beam

Description: Results from neutrino oscillation experiments in the last ten years have revolutionized the field of neutrino physics. While the overall oscillation picture for three neutrinos is now well established and precision measurements of the oscillation parameters are underway, crucial issues remain. In particular, the hierarchy of the neutrino masses, the structure of the neutrino mixing matrix, and, above all, CP violation in the neutrino sector are the primary experimental challenges in upcoming ye… more
Date: September 1, 2005
Creator: Finley, D.; Jensen, D.; Jostlein, H.; Marchionni, A.; Pordes, S.; Rapidis, P. A. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

X-Ray Diffraction and Raman Studies of Beryllium: Static and Elastic Properties at High Pressures

Description: We report combined x-ray and Raman studies of beryllium in helium or argon pressure medium at pressures approaching 200 GPa. Our results are generally consistent with recent studies confirming the stability of the hexagonal close-packed phase to the highest pressures. However, the quasi-hydrostatic conditions of our studies lead to a stiffer equation of state (K{sub 0} = 109.88, K'{sub 0} = 3.59) and a gradual approach toward a more ideal c/a ratio of 1.60 at 180 GPa. Combining our Raman and EO… more
Date: April 26, 2005
Creator: Evans, W. J.; Lipp, M. J.; Cynn, H.; Yoo, C. S.; Somayazulu, M.; Hausermann, D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Coarse-grained molecular dynamics: Nonlinear finite elements and finite temperature

Description: Coarse-grained molecular dynamics (CGMD) is a technique developed as a concurrent multiscale model that couples conventional molecular dynamics (MD) to a more coarse-grained description of the periphery. The coarse-grained regions are modeled on a mesh in a formulation that generalizes conventional finite element modeling (FEM) of continuum elasticity. CGMD is derived solely from the MD model, however, and has no continuum parameters. As a result, it provides a coupling that is smooth and provi… more
Date: May 30, 2005
Creator: Rudd, R E & Broughton, J Q
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Determining the neutrino mass hierarchy and CP violation in NoVA with a second off-axis detector

Description: We consider a Super-NOVA-like experimental configuration based on the use of two detectors in a long-baseline experiment as NOVA. We take the far detector as in the present NOVA proposal and add a second detector at a shorter baseline. The location of the second off-axis detector is chosen such that the ratio L/E is the same for both detectors, being L the baseline and E the neutrino energy. We consider liquid argon and water- Cerenkov techniques for the second off-axis detector and study, for … more
Date: October 1, 2005
Creator: Mena, Olga; Palomares-Ruiz, Sergio & Pascoli, Silvia
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Compatibility of the Radiating Divertor with High Performance Plasmas in DIII-D

Description: Excessive thermal power loading on the divertor structures presents a design difficulty for future-generation, high powered tokamaks. This difficulty may be mitigated by ''seeding'' the divertor with impurities which radiate a significant fraction of the power upstream of the divertor targets. For this ''radiating divertor'' concept to be practical, however, the confinement and stability of the plasma cannot be compromised by excessive leakage of the seeded impurities into the core plasma. One … more
Date: June 24, 2005
Creator: Petrie, T; Wade, M; Allen, S; Brooks, N; Fenstermacher, M; Ferron, J et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The Physics Analysis of a Gas Attenuator with Argon as a Working Gas

Description: A gas attenuator is an important element of the LCLS facility. The attenuator has to operate in a broad range of x-ray energies, provide attenuation coefficient between 1 and 10{sup 4} with the accuracy of 1% and, at the same time, be reliable and allow for many months of un-interrupted operation. A detailed design study of the attenuator based on the use of nitrogen as a working gas has been recently carried out by S. Shen et al [1]. In this note we assess the features of the attenuator based … more
Date: December 19, 2005
Creator: Ryutov, D. D.; Bionta, R. M.; McKernan, M. A.; Shen, S. & Trent, J. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Extending ion-track lithography to the low-energy ion regime

Description: Ion tracking and ion-track lithography have been performed almost exclusively using ions with energies near or above the maximum in electronic stopping, which occurs at {approx}1 MeV/amu. In this paper, ion-track lithography using ions with energies well below this maximum is discussed. The results of etching ion tracks created in polycarbonate films by ions with energies just above the anticipated threshold for creating etchable latent tracks with cylindrical geometry have been examined. Low-e… more
Date: October 14, 2005
Creator: Musket, R G
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Measurements of thermal accommodation coefficients.

Description: A previously-developed experimental facility has been used to determine gas-surface thermal accommodation coefficients from the pressure dependence of the heat flux between parallel plates of similar material but different surface finish. Heat flux between the plates is inferred from measurements of temperature drop between the plate surface and an adjacent temperature-controlled water bath. Thermal accommodation measurements were determined from the pressure dependence of the heat flux for a f… more
Date: October 1, 2005
Creator: Rader, Daniel John; Castaneda, Jaime N.; Torczynski, John R.; Grasser, Thomas W. & Trott, Wayne Merle
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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