Eddy Current Effect of the Bnl-Ags Vacuum Chamber on the Optics of the Bnl-Ags Synchrotron. (open access)

Eddy Current Effect of the Bnl-Ags Vacuum Chamber on the Optics of the Bnl-Ags Synchrotron.

During the acceleration cycle of the AGS synchrotron, eddy currents are generated within the walls of the vacuum chambers of the AGS main magnets. The vacuum chambers have elliptical cross section, are made of inconel material with a wall thickness of 2 mm and are placed within the gap of the combined-function main magnets of the AGS synchrotron. The generation of the eddy currents in the walls of the vacuum chambers, creates various magnetic multipoles, which affect the optics of the AGS machine. In this report these magnetic multipoles are calculated for various time interval starting at the acceleration cycle, where the magnetic field of the main magnet is {approx}0.1 T, and ending before the beam extraction process, where the magnetic field of the main magnet is almost constant at {approx}1.1 T. The calculations show that the magnetic multipoles generated by the eddy-currents affect the optics of the AGS synchrotron during the acceleration cycle and in particular at low magnetic fields of the main magnet. Their effect is too weak to affect the optics of the AGS machine during beam extraction at the nominal energies.
Date: March 29, 1999
Creator: Tsoupas, N.; Ahrens, L.; Brown, K. A.; Glenn, J. W. & Gardner, K.
Object Type: Article
System: The UNT Digital Library
Absolute dipole gamma-ray strength functions for /sup 176/Lu (open access)

Absolute dipole gamma-ray strength functions for /sup 176/Lu

We have derived absolute dipole strength-function information for /sup 176/Lu from an average resonance capture study of /sup 175/Lu with 2-keV neutrons, and from neutron capture cross-section measurements with neutrons from 30 keV to about 1 MeV. We found that we needed to increase our previous estimate of the relative M1/E1 strengths near 5 MeV by a factor of 3, and to revise downward the absolute magnitude of our E1 strength function. We accomplished the latter, while still maintaining continuity with the photonuclear data, by adjusting the one free parameter in our line shape. The present E1 and M1 strengths now seem correct both near the neutron separation energy and also around 1 MeV.
Date: August 29, 1984
Creator: Gardner, D. G.; Gardner, M. A. & Hoff, R. W.
Object Type: Article
System: The UNT Digital Library
Isomer ratio calculations using modeled discrete levels (open access)

Isomer ratio calculations using modeled discrete levels

We have calculated isomer ratios for the /sup 175/Lu(n,..gamma..), /sup 175/Lu(n,2n), /sup 237/Np(n,2n), /sup 241/Am(n,..gamma..), and /sup 243/Am(n,..gamma..) reactions using modeled level structures in the deformed, odd-odd product nuclei. We find: that the hundreds of discrete levels and their gamma-ray branching ratios provided by the modeling are necessary to achieve agreement with experiment, that many rotational bands must be included in order to obtain a sufficiently representative selection of K quantum numbers, and that the levels of each band must be extended to appropriately high values of angular momentum. 8 references.
Date: August 29, 1984
Creator: Gardner, M. A.; Gardner, D. G. & Hoff, R. W.
Object Type: Article
System: The UNT Digital Library
Use of gamma ray strength functions for predicting the neutron capture cross section of /sup 88/Y (open access)

Use of gamma ray strength functions for predicting the neutron capture cross section of /sup 88/Y

The present study indicates that the estimation of the gamma-ray strength function is the approach least subject to error when unmeasured capture cross sections are to be computed. An estimate is given for the /sup 88/..gamma..(n,..gamma..) cross section.
Date: July 29, 1977
Creator: Gardner, D. G. & Gardner, M. A.
Object Type: Report
System: The UNT Digital Library
An Alternative Lattice for the Spallation Neutron Source Accumulator Ring. (open access)

An Alternative Lattice for the Spallation Neutron Source Accumulator Ring.

As a key component of the Spallation Neutron Source (SNS) Project, the Accumulator Ring will collect the proton beam from the SNS LINAC at an intensity of 2 x 10{sup 14} per pulse at 60 Hz for a total power of 2 MW, exceeding present performance value of existing facilities. Requirements of minimum beam loss for hands-on maintenance and flexibility for future upgrade are essential for the lattice design. In this paper, we study an alternative lattice emphasizing various injection schemes and flexibility for future upgrade. Working points, sextupole families for chromaticity control, and alternate extraction schemes are also considered.
Date: March 29, 1999
Creator: Gardner, C. J.; Lee, Y. Y.; Tsoupas, N. & Wei, J.
Object Type: Article
System: The UNT Digital Library
Draft versus finished sequence data for DNA and protein diagnostic signature development (open access)

Draft versus finished sequence data for DNA and protein diagnostic signature development

Sequencing pathogen genomes is costly, demanding careful allocation of limited sequencing resources. We built a computational Sequencing Analysis Pipeline (SAP) to guide decisions regarding the amount of genomic sequencing necessary to develop high-quality diagnostic DNA and protein signatures. SAP uses simulations to estimate the number of target genomes and close phylogenetic relatives (near neighbors, or NNs) to sequence. We use SAP to assess whether draft data is sufficient or finished sequencing is required using Marburg and variola virus sequences. Simulations indicate that intermediate to high quality draft with error rates of 10{sup -3}-10{sup -5} ({approx} 8x coverage) of target organisms is suitable for DNA signature prediction. Low quality draft with error rates of {approx} 1% (3x to 6x coverage) of target isolates is inadequate for DNA signature prediction, although low quality draft of NNs is sufficient, as long as the target genomes are of high quality. For protein signature prediction, sequencing errors in target genomes substantially reduce the detection of amino acid sequence conservation, even if the draft is of high quality. In summary, high quality draft of target and low quality draft of NNs appears to be a cost-effective investment for DNA signature prediction, but may lead to underestimation …
Date: October 29, 2004
Creator: Gardner, S N; Lam, M W; Smith, J R; Torres, C L & Slezak, T R
Object Type: Article
System: The UNT Digital Library
High Intensity Performance of the Brookhaven AGS. (open access)

High Intensity Performance of the Brookhaven AGS.

The Brookhaven AGS provides 24 GeV protons for a multi-user program of fixed-target high energy physics experiments, such as the study of extremely rare Kaon decays. Up to 7 x 10{sup 13} protons are slowly extracted over 2.2 seconds each 5.1 seconds. The muon storage ring of the g-2 experiment is supplied with bunches of 7 x 10{sup 12} protons. Since the completion of the a 1.9 GeV Booster synchrotron and installation of a new high-power rf system and transition jump system in the AGS various modes of operation have been explored to overcome space charge limits and beam instabilities at these extreme beam intensities. Experiments have been done using barrier cavities to enable accumulation of debunched beam in the AGS as a potential path to significantly higher intensities. We report on the present understanding of intensity limitations and prospects for overcoming them.
Date: March 29, 1999
Creator: Ahrens, L. A.; Alessi, J.; Blaskiewicz, M.; Brennan, J. M.; Brown, K.; Gardner, C. et al.
Object Type: Article
System: The UNT Digital Library
Turn-by-Turn Analysis of Proton and Gold Beams at Injection in the AGS Booster. (open access)

Turn-by-Turn Analysis of Proton and Gold Beams at Injection in the AGS Booster.

In this paper we describe the latest version of a program we have used for several years to acquire and analyze turn-by-turn data from pick-up electrodes in the AGS Booster during injection. The program determines several parameters of the injected beam including the tunes and the position and angle of the incoming beam. Examples are given for both proton and gold injection.
Date: March 29, 1999
Creator: Gardner, C.; Ahrens, L. & Williams, N.
Object Type: Article
System: The UNT Digital Library
Beam-Loss Driven Design Optimization for the Spallation Neutron Source (SNS) Ring. (open access)

Beam-Loss Driven Design Optimization for the Spallation Neutron Source (SNS) Ring.

This paper summarizes three-stage design optimization for the Spallation Neutron Source (SNS) ring: linear machine design (lattice, aperture, injection, magnet field errors and misalignment), beam core manipulation (painting, space charge, instabilities, RF requirements), and beam halo consideration (collimation, envelope variation, e-p issues etc.).
Date: March 29, 1999
Creator: Wei, J.; Beebe-Wang, J.; Blaskiewicz, M.; Cameron, P.; Danby, G.; Gardner, C. J. et al.
Object Type: Article
System: The UNT Digital Library
Modeling of Long-Range Atmospheric Lasercom Links Between Static and Mobile Platforms (open access)

Modeling of Long-Range Atmospheric Lasercom Links Between Static and Mobile Platforms

We describe modeling and simulation of long-range terrestrial laser communications links between static and mobile platforms. Atmospheric turbulence modeling, along with pointing, tracking and acquisition models are combined to provide an overall capability to estimate communications link performance.
Date: July 29, 2003
Creator: Scharlemann, E T; Breitfeller, E F; Henderson, J R; Kallman, J S; Morris, J R & Ruggiero, A J
Object Type: Article
System: The UNT Digital Library
China Spallation Neutron Source Design (open access)

China Spallation Neutron Source Design

The China Spallation Neutron Source (CSNS) is an accelerator-based high-power project currently in preparation under the direction of the Chinese Academy of Sciences (CAS). The complex is based on an H- linear accelerator, a rapid cycling proton synchrotron accelerating the beam to 1.6 GeV, a solid tungsten target station, and five initial instruments for spallation neutron applications. The facility will operate at 25 Hz repetition rate with a phase-I beam power of about 120 kW. The major challenge is to build a robust and reliable user's facility with upgrade potential at a fractional of ''world standard'' cost.
Date: January 29, 2007
Creator: Wei, J.
Object Type: Article
System: The UNT Digital Library
Simulation of landscape disturbances and the effect of climatic change. Final report, July 15, 1989--July 14, 1990 (open access)

Simulation of landscape disturbances and the effect of climatic change. Final report, July 15, 1989--July 14, 1990

The purpose of this research is to understand how changes in climate may affect the structure of landscapes that are subject to periodic disturbances. A general model useful for examining the linkage between climatic change and landscape change has been developed. The model makes use of synoptic climatic data, a geographical information system (GRASS), field data on the location of disturbance patches, simulation code written in the SIMSCRIPT language, and a set of landscape structure analysis programs written specifically for this research project. A simplified version of the model, lacking the climatic driver, has been used to analyze how changes in disturbance regimes (in this case settlement and fire suppression) affect landscape change. Landscape change lagged in its response to changes in the disturbance regime, but the lags differed depending upon the character of the change and the particular measure considered. The model will now be modified for use in a specific setting to analyze the effects of changes in climate on the structure of flood-disturbed patches along the Animas River, Colorado.
Date: January 29, 1993
Creator: Baker, W. L.
Object Type: Report
System: The UNT Digital Library
Simulation of landscape disturbances and the effect of climatic change (open access)

Simulation of landscape disturbances and the effect of climatic change

The purpose of this research is to understand how changes in climate may affect the structure of landscapes that are subject to periodic disturbances. A general model useful for examining the linkage between climatic change and landscape change has been developed. The model makes use of synoptic climatic data, a geographical information system (GRASS), field data on the location of disturbance patches, simulation code written in the SIMSCRIPT language, and a set of landscape structure analysis programs written specifically for this research project. A simplified version of the model, lacking the climatic driver, has been used to analyze how changes in disturbance regimes (in this case settlement and fire suppression) affect landscape change. Landscape change lagged in its response to changes in the disturbance regime, but the lags differed depending upon the character of the change and the particular measure considered. The model will now be modified for use in a specific setting to analyze the effects of changes in climate on the structure of flood-disturbed patches along the Animas River, Colorado.
Date: January 29, 1993
Creator: Baker, W.L.
Object Type: Report
System: The UNT Digital Library
Hadron Spectroscopy and Structure from AdS/CFT (open access)

Hadron Spectroscopy and Structure from AdS/CFT

The AdS/CFT correspondence between conformal field theory and string states in an extended space-time has provided new insights into not only hadron spectra, but also their light-front wavefunctions. We show that there is an exact correspondence between the fifth-dimensional coordinate of anti-de Sitter space z and a specific impact variable {zeta} which measures the separation of the constituents within the hadron in ordinary space-time. This connection allows one to predict the form of the light-front wavefunctions of mesons and baryons, the fundamental entities which encode hadron properties and scattering amplitudes. A new relativistic Schroedinger light-front equation is found which reproduces the results obtained using the fifth-dimensional theory. Since they are complete and orthonormal, the AdS/CFT model wavefunctions can be used as an initial ansatz for a variational treatment or as a basis for the diagonalization of the light-front QCD Hamiltonian. A number of applications of light-front wavefunctions are also discussed.
Date: September 29, 2006
Creator: Brodsky, Stanley J.
Object Type: Article
System: The UNT Digital Library
Novel Heavy Quark Phenomena in QCD (open access)

Novel Heavy Quark Phenomena in QCD

None
Date: January 29, 2014
Creator: Brodsky, Stanley J.
Object Type: Article
System: The UNT Digital Library
Study of Longitudinal Injection/Stacking in the SNS Acummulator Ring. (open access)

Study of Longitudinal Injection/Stacking in the SNS Acummulator Ring.

Various longitudinal distributions, resulting from the specific injection and stacking methods, are considered to minimize longitudinal and transverse instabilities and particle losses in SNS accumulator ring. The longitudinal phase space paintings by linac energy ramping, increased linac energy spread and the use of a random phase RF debunching cavity are reported. Bunch lengthening and beam in gap rate as functions of injection energy spread, RF voltage and injection energy error is summarized. Finally, the energy error tolerance is concluded.
Date: March 29, 1999
Creator: Beebe-Wang, J.
Object Type: Article
System: The UNT Digital Library
TANK 4 CHARACTERIZATION, SETTLING, AND WASHING STUDIES (open access)

TANK 4 CHARACTERIZATION, SETTLING, AND WASHING STUDIES

A sample of PUREX sludge from Tank 4 was characterized, and subsequently combined with a Tank 51 sample (Tank 51-E1) received following Al dissolution, but prior to a supernate decant by the Tank Farm, to perform a settling and washing study to support Sludge Batch 6 preparation. The sludge source for the majority of the Tank 51-E1 sample is Tank 12 HM sludge. The Tank 51-E1 sample was decanted by SRNL prior to use in the settling and washing study. The Tank 4 sample was analyzed for chemical composition including noble metals. The characterization of the Tank 51-E1 sample, used here in combination with the Tank 4 sample, was reported previously. SRNL analyses on Tank 4 were requested by Liquid Waste Engineering (LWE) via Technical Task Request (TTR) HLE-TTR-2009-103. The sample preparation work is governed by Task Technical and Quality Assurance Plan (TTQAP), and analyses were controlled by an Analytical Study Plan and modifications received via customer communications. Additional scope included a request for a settling study of decanted Tank 51-E1 and a blend of decanted Tank 51-E1 and Tank 4, as well as a washing study to look into the fate of undissolved sulfur observed during the Tank 4 …
Date: September 29, 2009
Creator: Bannochie, C.; Pareizs, J.; Click, D. & Zamecnik, J.
Object Type: Report
System: The UNT Digital Library
Use of Electrochemical Noise to Assess Corrosion in Kraft Continuous Digesters (open access)

Use of Electrochemical Noise to Assess Corrosion in Kraft Continuous Digesters

Electrochemical noise (EN) probes were deployed in two continuous kraft digesters at a variety of locations representative of corrosion throughout the vessels. Current and potential noise, the temperature at each probe location, and the value of up to 60 process parameters (flow rates, liquor chemistry, etc.) were monitored continuously during each experiment. The results indicate that changes in furnish composition and process upsets were invariably associated with concurrent substantial changes in EN activity throughout the vessels. Post-test evaluation of the mild steel electrode materials in both vessels confirmed general corrosion of a magnitude consistent with historical trends in the respective vessels as well as values qualitatively (and semi-quantitatively) related to EN current sums for each electrode pair. Stainless steel electrodes representing 309LSi and 312 overlay repairs exhibited zero wastage corrosion--as did the actual overlays--but the EN data indicated periodic redox activity on the stainless steel that varied with time and position within the vessel. Little or no correlation between EN probe activity and other operational variables was observed in either vessel. Additional details for each digester experiment are summarized.
Date: November 29, 2004
Creator: Pawel, S.J.
Object Type: Report
System: The UNT Digital Library
Far-Field Accumulation of Fissile Material From Waste Packages Containing Plutonium Disposition Waste Form (open access)

Far-Field Accumulation of Fissile Material From Waste Packages Containing Plutonium Disposition Waste Form

The objective of this calculation is to estimate the quantity of fissile material that could accumulate in fractures in the rock beneath plutonium-ceramic (Pu-ceramic) and Mixed-Oxide (MOX) waste packages (WPs) as they degrade in the potential monitored geologic repository at Yucca Mountain. This calculation is to feed another calculation (Ref. 31) computing the probability of criticality in the systems described in Section 6 and then ultimately to a more general report on the impact of plutonium on the performance of the proposed repository (Ref. 32), both developed concurrently to this work. This calculation is done in accordance with the development plan TDP-DDC-MD-000001 (Ref. 9), item 5. The original document described in item 5 has been split into two documents: this calculation and Ref. 4. The scope of the calculation is limited to only very low flow rates because they lead to the most conservative cases for Pu accumulation and more generally are consistent with the way the effluent from the WP (called source term in this calculation) was calculated (Ref. 4). Ref. 4 (''In-Drift Accumulation of Fissile Material from WPs Containing Plutonium Disposition Waste Forms'') details the evolution through time (breach time is initial time) of the chemical composition of …
Date: September 29, 2000
Creator: Nicot, J.P.
Object Type: Report
System: The UNT Digital Library
PET IMAGING STUDIES IN DRUG ABUSE RESEARCH. (open access)

PET IMAGING STUDIES IN DRUG ABUSE RESEARCH.

There is overwhelming evidence that addiction is a disease of the brain (Leshner, 1997). Yet public perception that addiction is a reflection of moral weakness or a lack of willpower persists. The insidious consequence of this perception is that we lose sight of the fact that there are enormous medical consequences of addiction including the fact that a large fraction of the total deaths from cancer and heart disease are caused by smoking addiction. Ironically the medical school that educates physicians in addiction medicine and the cancer hospital that has a smoking cessation clinic are vanishingly rare and efforts at harm reduction are frequently met with a public indignation. Meanwhile the number of people addicted to substances is enormous and increasing particularly the addictions to cigarettes and alcohol. It is particularly tragic that addiction usually begins in adolescence and becomes a chronic relapsing problem and there are basically no completely effective treatments. Clearly we need to understand how drugs of abuse affect the brain and we need to be creative in using this information to develop effective treatments. Imaging technologies have played a major role in the conceptualization of addiction as a disease of the brain (Fowler et al., 1998a; …
Date: January 29, 2001
Creator: Fowler, J. S.; Volkow, N. D.; Ding, Y. S.; Logan, J. & Wang, G. J.
Object Type: Book
System: The UNT Digital Library
Development of Novel Water-Gas Shift Membrane Reactor (open access)

Development of Novel Water-Gas Shift Membrane Reactor

None
Date: December 29, 2004
Creator: Ho, W. S. Winston
Object Type: Report
System: The UNT Digital Library
Development of Novel Water-Gas Shift Membrane Reactor (open access)

Development of Novel Water-Gas Shift Membrane Reactor

This report summarizes the objectives, technical barrier, approach, and accomplishments for the development of a novel water-gas-shift (WGS) membrane reactor for hydrogen enhancement and CO reduction. We have synthesized novel CO{sub 2}-selective membranes with high CO{sub 2} permeabilities and high CO{sub 2}/H{sub 2} and CO{sub 2}/CO selectivities by incorporating amino groups in polymer networks. We have also developed a one-dimensional non-isothermal model for the countercurrent WGS membrane reactor. The modeling results have shown that H{sub 2} enhancement (>99.6% H{sub 2} for the steam reforming of methane and >54% H{sub 2} for the autothermal reforming of gasoline with air on a dry basis) via CO{sub 2} removal and CO reduction to 10 ppm or lower are achievable for synthesis gases. With this model, we have elucidated the effects of system parameters, including CO{sub 2}/H{sub 2} selectivity, CO{sub 2} permeability, sweep/feed flow rate ratio, feed temperature, sweep temperature, feed pressure, catalyst activity, and feed CO concentration, on the membrane reactor performance. Based on the modeling study using the membrane data obtained, we showed the feasibility of achieving H{sub 2} enhancement via CO{sub 2} removal, CO reduction to {le} 10 ppm, and high H{sub 2} recovery. Using the membrane synthesized, we have obtained …
Date: December 29, 2004
Creator: Ho, W. S. Winston
Object Type: Report
System: The UNT Digital Library
Transverse Phase Space Painting for Sns Accumulator Ring Injection. (open access)

Transverse Phase Space Painting for Sns Accumulator Ring Injection.

The result of investigation and comparison of a series of transverse phase space painting schemes for the injection of SNS accumulator ring [1] is reported. In this computer simulation study, the focus is on the creation of closed orbit bumps that give desired distributions at the target. Space charge effects such as tune shift, emittance growth and beam losses are considered. The results of pseudo end-to-end simulations from the injection to the target through the accumulator ring and Ring to Target Beam Transfer (RTBT) system [2] are presented and discussed.
Date: March 29, 1999
Creator: Beebe-Wang, J.; Lee, Y. Y.; Raparia, D. & Wei, J.
Object Type: Article
System: The UNT Digital Library