1 GeV CW nonscaling FFAG for ADS, and magnet parameters (open access)

1 GeV CW nonscaling FFAG for ADS, and magnet parameters

Multi-MW proton driver capability remains a challenging, critical technology for many core HEP programs, particularly the neutrino ones such as the Muon Collider and Neutrino factory, and for high-profile energy applications such as Accelerator Driven Subcritical Reactors (ADS) and Accelerator Transmutation of Waste for nuclear power and waste management. Work is focused almost exclusively on an SRF linac, as, to date, no re-circulating accelerator can attain the 10-20 MW capability necessary for the nuclear applications. Recently, the concept of isochronous orbits has been explored and developed for nonscaling FFAGs using powerful new methodologies in FFAG accelerator design. Work is progressing on a stable, high-intensity, 1 GeV isochronous FFAG. Initial specifications of novel magnets with the nonlinear radial fields required to support isochronous operation are also reported here.
Date: May 20, 2012
Creator: Johnstone, C.; Meot, F.; Snopok, P. & Weng, W.
Object Type: Article
System: The UNT Digital Library
2011 Annual Summary Report for the Area 3 and Area 5 Radioactive Waste Management Sites at the Nevada National Security Site, Nye County, Nevada: Review of the Performance Assessments and Composite Analyses (open access)

2011 Annual Summary Report for the Area 3 and Area 5 Radioactive Waste Management Sites at the Nevada National Security Site, Nye County, Nevada: Review of the Performance Assessments and Composite Analyses

The Maintenance Plan for the Performance Assessments and Composite Analyses for the Area 3 and Area 5 Radioactive Waste Management Sites at the Nevada Test Site (National Security Technologies, LLC, 2007a) requires an annual review to assess the adequacy of the Performance Assessments (PAs) and Composite Analyses (CAs), with the results submitted annually to U.S. Department of Energy (DOE) Office of Environmental Management. The Disposal Authorization Statements for the Area 3 and Area 5 Radioactive Waste Management Sites (RWMSs) also require that such reviews be made and that secondary or minor unresolved issues be tracked and addressed as part of the maintenance plan (DOE, 1999a; 2000). The U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office performed an annual review of the Area 3 and Area 5 RWMS PAs and CAs for fiscal year (FY) 2011. This annual summary report presents data and conclusions from the FY 2011 review, and determines the adequacy of the PAs and CAs. Operational factors (e.g., waste forms and containers, facility design, and waste receipts), closure plans, monitoring results, and research and development (R and D) activities were reviewed to determine the adequacy of the PAs. Likewise, the environmental restoration activities at the …
Date: March 20, 2012
Creator: NSTec Environmental Management
Object Type: Report
System: The UNT Digital Library
2012 ATOMIC AND MOLECULAR INTERACTIONS GORDON RESEARCH CONFERENCE AND GORDON RESEARCH SEMINAR, JULY 15-20, 2012 (open access)

2012 ATOMIC AND MOLECULAR INTERACTIONS GORDON RESEARCH CONFERENCE AND GORDON RESEARCH SEMINAR, JULY 15-20, 2012

At the 2012 Atomic and Molecular Interactions Gordon Conference, there will be talks in several broadly defined and partially overlapping areas:  Intramolecular and single-collision reaction dynamics;  Photophysics and photochemistry of excited states;  Clusters, aerosols and solvation;  Interactions at interfaces;  Conformations and folding of large molecules;  Interactions under extreme conditions of temperature and pressure. The theme of the Gordon Research Seminar on Atomic & Molecular Interactions, in keeping with the tradition of the Atomic and Molecular Interactions Gordon Research Conference, is far-reaching and involves fundamental research in the gas and condensed phases along with application of these ideas to practical chemical fields. The oral presentations, which will contain a combination of both experiment and theory, will focus on four broad categories:  Ultrafast Phenomena;  Excited States, Photoelectrons, and Photoions;  Chemical Reaction Dynamics;  Biomolecules and Clusters.
Date: July 20, 2012
Creator: Zwier, Timothy
Object Type: Article
System: The UNT Digital Library
2012 SINGLE MOLECULE APPROACHES TO BIOLOGY GORDON RESEARCH CONFERENCE (JULY 15-20, 2012 - MOUNT SNOW RESORT, WEST DOVER VT) (open access)

2012 SINGLE MOLECULE APPROACHES TO BIOLOGY GORDON RESEARCH CONFERENCE (JULY 15-20, 2012 - MOUNT SNOW RESORT, WEST DOVER VT)

Single molecule techniques are rapidly occupying a central role in biological research at all levels. This transition was made possible by the availability and dissemination of robust techniques that use fluorescence and force probes to track the conformation of molecules one at a time, in vitro as well as in live cells. Single-molecule approaches have changed the way many biological problems are studied. These novel techniques provide previously unobtainable data on fundamental biochemical processes that are essential for all forms of life. The ability of single-molecule approaches to avoid ensemble averaging and to capture transient intermediates and heterogeneous behavior renders them particularly powerful in elucidating mechanisms of the molecular systems that underpin the functioning of living cells. Hence, our conference seeks to disseminate the implementation and use of single molecule techniques in the pursuit of new biological knowledge. Topics covered include: Molecular Motors on the Move; Origin And Fate Of Proteins; Physical Principles Of Life; Molecules and Super-resolution Microscopy; Nanoswitches In Action; Active Motion Or Random Diffusion?; Building Blocks Of Living Cells; From Molecular Mechanics To Physiology; Tug-of-war: Force Spectroscopy Of Single Proteins.
Date: April 20, 2012
Creator: Fernandez, Julio
Object Type: Article
System: The UNT Digital Library
3D Equilibrium Effects Due to RMP Application on DIII-D (open access)

3D Equilibrium Effects Due to RMP Application on DIII-D

The mitigation and suppression of edge localized modes (ELMs) through application of resonant magnetic perturbations (RMPs) in Tokamak plasmas is a well documented phenomenon [1]. Vacuum calculations suggest the formation of edge islands and stochastic regions when RMPs are applied to the axisymmetric equilibria. Self-consistent calculations of the plasma equilibrium with the VMEC [2] and SPEC [3] codes have been performed for an up-down symmetric shot (142603) in DIII-D. In these codes, a self-consistent calculation of the plasma response due to the RMP coils is calculated. The VMEC code globally enforces the constraints of ideal MHD; consequently, a continuously nested family of flux surfaces is enforced throughout the plasma domain. This approach necessarily precludes the observation of islands or field-line chaos. The SPEC code relaxes the constraints of ideal MHD locally, and allows for islands and field line chaos at or near the rational surfaces. Equilibria with finite pressure gradients are approximated by a set of discrete "ideal-interfaces" at the most irrational flux surfaces and where the strongest pressure gradients are observed. Both the VMEC and SPEC calculations are initialized from EFIT reconstructions of the plasma that are consistent with the experimental pressure and current profiles. A 3D reconstruction using …
Date: June 20, 2012
Creator: Lazerson, S.; Lazarus, E.; Hudson, S.; Pablant, N. & Gates, D.
Object Type: Article
System: The UNT Digital Library
3D Equilibrium Effects Due to RMP Application on DIII-D (open access)

3D Equilibrium Effects Due to RMP Application on DIII-D

The mitigation and suppression of edge localized modes (ELMs) through application of resonant magnetic perturbations (RMPs) in Tokamak plasmas is a well documented phenomenon. Vacuum calculations suggest the formation of edge islands and stochastic regions when RMPs are applied to the axisymmetric equilibria. Self-consistent calculations of the plasma equilibrium with the VMEC and SPEC codes have been performed for an up-down symmetric shot in DIII-D. In these codes, a self-consistent calculation of the plasma response due to the RMP coils is calculated. The VMEC code globally enforces the constraints of ideal MHD; consequently, a continuously nested family of flux surfaces is enforced throughout the plasma domain. This approach necessarily precludes the observation of islands or field-line chaos. The SPEC code relaxes the constraints of ideal MHD locally, and allows for islands and field line chaos at or near the rational surfaces. Equilibria with finite pressure gradients are approximated by a set of discrete "ideal-interfaces" at the most irrational flux surfaces and where the strongest pressure gradients are observed. Both the VMEC and SPEC calculations are initialized from EFIT reconstructions of the plasma that are consistent with the experimental pressure and current profiles. A 3D reconstruction using the STELLOPT code, which …
Date: June 20, 2012
Creator: Lazerson, S.; Lazarus, E.; Hudson, S.; Pablant, N. & Gates, D.
Object Type: Report
System: The UNT Digital Library
3D simulations of multipacting in the 56 MHz SRF cavity (open access)

3D simulations of multipacting in the 56 MHz SRF cavity

The 56 MHz SRF Quarter-Wave Resonator (QWR) is designed for RHIC as a storage cavity to improve the collider performance. 2D multipacting simulation has been done for the cavity alone. Ripples were added to the outer body of the cavity for multipacting suppression based on the simulation findings. During operation, there will be four higher order mode (HOM) couplers. All of these components will be exposed to high RF fields. In this paper we compare 2D and 3D codes simulation results for multipacting in the cavity. We also report 3D simulation results for multipacting simulation at the couplers.
Date: May 20, 2012
Creator: Q., Wu; Belomestnykh, S.; Ge, L.; Ko, K.; Li, Z.; Ng, C. et al.
Object Type: Article
System: The UNT Digital Library
The AGS synchrotron with four helical magnets (open access)

The AGS synchrotron with four helical magnets

The idea of using two partial helical magnets was applied successfully to the AGS synchrotron to preserve the proton beam polarization. In this paper we explore in details the idea of using four helical magnets placed symmetrically in the AGS ring. The placement of four helical magnets in the AGS ring provides many advantages over the present setup of the AGS which uses two partial helical magnets. First, the symmetric placement of the four helical magnets allows for a better control of the AGS optics with reduced values of the beta functions especially near beam injection, second, the vertical spin direction during beam injection and extraction is closer to vertical, and third, it provides for a larger 'spin tune gap', which allows the vertical and horizontal tunes to be placed, and prevent the horizontal and vertical intrinsic spin resonances of the AGS to occur during the acceleration cycle. Although the same spin gap can be obtained with a single or two partial helices, the required high field strength of a single helix makes its use impractical, and that of the double helix rather difficult. In this paper we will provide results on the spin tune and on the optics of …
Date: May 20, 2012
Creator: Tsoupas, N.; Huang, H.; Roser, T.; MacKay, W. W. & Trbojevic, D.
Object Type: Article
System: The UNT Digital Library
Analysis of beam loss induced abort kicker instability (open access)

Analysis of beam loss induced abort kicker instability

Through more than a decade of operation, we have noticed the phenomena of beam loss induced kicker instability in the RHIC beam abort systems. In this study, we analyze the short term beam loss before abort kicker pre-fire events and operation conditions before capacitor failures. Beam loss has caused capacitor failures and elevated radiation level concentrated at failed end of capacitor has been observed. We are interested in beam loss induced radiation and heat dissipation in large oil filled capacitors and beam triggered thyratron conduction. We hope the analysis result would lead to better protection of the abort systems and improved stability of the RHIC operation.
Date: May 20, 2012
Creator: Zhang, W.; Sandberg, J.; Ahrens, L.; Fischer, W.; Hahn, H.; Mi, J. et al.
Object Type: Article
System: The UNT Digital Library
ANALYSIS OF DWPF SLUDGE BATCH 6 (MACROBATCH 7) POUR STREAM GLASS SAMPLES (open access)

ANALYSIS OF DWPF SLUDGE BATCH 6 (MACROBATCH 7) POUR STREAM GLASS SAMPLES

The Defense Waste Processing Facility (DWPF) began processing Sludge Batch 6 (SB6), also referred to as Macrobatch 7 (MB7), in June 2010. SB6 is a blend of the heel of Tank 40 from Sludge Batch 5 (SB5), H-Canyon Np transfers and SB6 that was transferred to Tank 40 from Tank 51.1 SB6 was processed using Frit 418. Sludge is received into the DWPF Chemical Processing Cell (CPC) and is processed through the Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator Tank (SME). The treated sludge slurry is then transferred to the Melter Feed Tank (MFT) and fed to the melter. During processing of each sludge batch, the DWPF is required to take at least one glass sample to meet the objectives of the Glass Product Control Program (GPCP) and to complete the necessary Production Records so that the final glass product may be disposed of at a Federal Repository. The DWPF requested various analyses of radioactive glass samples obtained from the melter pour stream during processing of SB6 as well as reduction/oxidation (REDOX) analysis of MFT samples to determine the impact of Argon bubbling. Sample analysis followed the Task Technical and Quality Assurance Plan (TTQAP) and an Analytical …
Date: January 20, 2012
Creator: Johnson, F.
Object Type: Report
System: The UNT Digital Library
Analysis of kicker noise induced beam emittance growth (open access)

Analysis of kicker noise induced beam emittance growth

Over the last few years, physicists have occasionally observed the presence of noise acting on the RHIC beams leading to emittance growth at high beam energies. While the noise was sporadic in the past, it became persistent during the Run-11 setup period. An investigation diagnosed the source as originating from the RHIC dump kicker system. Once identified the issue was quickly resolved. We report in this paper the investigation result, circuit analysis, measured and simulated waveforms, solutions, and future plans.
Date: May 20, 2012
Creator: Zhang, W.; Sandberg, J.; Ahrens, L.; Blacker, I. M.; Brennan, M.; Blaskiewicz, M. et al.
Object Type: Article
System: The UNT Digital Library
ANALYSIS OF THE TANK 5F FINAL CHARATERIZATION SAMPLES-2011 (open access)

ANALYSIS OF THE TANK 5F FINAL CHARATERIZATION SAMPLES-2011

The Savannah River National Laboratory (SRNL) was requested by SRR to provide sample preparation and analysis of the Tank 5F final characterization samples to determine the residual tank inventory prior to grouting. Two types of samples were collected and delivered to SRNL: floor samples across the tank and subsurface samples from mounds near risers 1 and 5 of Tank 5F. These samples were taken from Tank 5F between January and March 2011. These samples from individual locations in the tank (nine floor samples and six mound Tank 5F samples) were each homogenized and combined in a given proportion into 3 distinct composite samples to mimic the average composition in the entire tank. These Tank 5F composite samples were analyzed for radiological, chemical and elemental components. Additional measurements performed on the Tank 5F composite samples include bulk density and water leaching of the solids to account for water soluble species. With analyses for certain challenging radionuclides as the exception, all composite Tank 5F samples were analyzed and reported in triplicate. The target detection limits for isotopes analyzed were based on customer desired detection limits as specified in the technical task request documents. SRNL developed new methodologies to meet these target detection …
Date: January 20, 2012
Creator: Oji, L.; Diprete, D.; Coleman, C. & Hay, M.
Object Type: Report
System: The UNT Digital Library
ANALYTICAL RESULTS OF MOX COLEMANITE CONCRETE SAMPLE PBC-44.2 (open access)

ANALYTICAL RESULTS OF MOX COLEMANITE CONCRETE SAMPLE PBC-44.2

The Mixed Oxide Fuel Fabrication Facility (MFFF) will use colemanite bearing concrete neutron absorber panels credited with attenuating neutron flux in the criticality design analyses and shielding operators from radiation. The Savannah River National Laboratory is tasked with measuring the total density, partial hydrogen density, and partial boron density of the colemanite concrete. Sample PBC-44.2 was received on 9/20/2012 and analyzed. The average total density measured by the ASTM method C 642 was 2.03 g/cm{sup 3}, within the lower bound of 1.88 g/cm3. The average partial hydrogen density was 6.64E-02 g/cm{sup 3} as measured using method ASTM E 1311 and met the lower bound of 6.04E-02 g/cm{sup 3}. The average measured partial boron density was 1.70E-01 g/cm{sup 3} which met the lower bound of 1.65E-01 g/cm{sup 3} measured by the ASTM C 1301 method.
Date: December 20, 2012
Creator: Best, D.; Cozzi, A. & Reigel, M.
Object Type: Report
System: The UNT Digital Library
ANALYTICAL RESULTS OF MOX COLEMANITE CONCRETE SAMPLES POURED AUGUST 29, 2012 (open access)

ANALYTICAL RESULTS OF MOX COLEMANITE CONCRETE SAMPLES POURED AUGUST 29, 2012

The Mixed Oxide Fuel Fabrication Facility (MFFF) will use colemanite bearing concrete neutron absorber panels credited with attenuating neutron flux in the criticality design analyses and shielding operators from radiation. The Savannah River National Laboratory is tasked with measuring the total density, partial hydrogen density, and partial boron density of the colemanite concrete. Samples poured 8/29/12 were received on 9/20/2012 and analyzed. The average total density of each of the samples measured by the ASTM method C 642 was within the lower bound of 1.88 g/cm{sup 3}. The average partial hydrogen density of samples 8.6.1, 8.7.1, and 8.5.3 as measured using method ASTM E 1311 met the lower bound of 6.04E-02 g/cm{sup 3}. The average measured partial boron density of each sample met the lower bound of 1.65E-01 g/cm{sup 3} measured by the ASTM C 1301 method. The average partial hydrogen density of samples 8.5.1, 8.6.3, and 8.7.3 did not meet the lower bound. The samples, as received, were not wrapped in a moist towel as previous samples and appeared to be somewhat drier. This may explain the lower hydrogen partial density with respect to previous samples.
Date: December 20, 2012
Creator: Best, D.; Cozzi, A. & Reigel, M.
Object Type: Report
System: The UNT Digital Library
THE APPARENT SOLUBILITY OF ALUMINUM(III) IN HANFORD HIGH-LEVEL WASTE TANKS (open access)

THE APPARENT SOLUBILITY OF ALUMINUM(III) IN HANFORD HIGH-LEVEL WASTE TANKS

The solubility of aluminum in Hanford nuclear waste impacts on the process ability of the waste by a number of proposed treatment options. For many years, Hanford staff has anecdotally noted that aluminum appears to be considerably more soluble in Hanford waste than the simpler electrolyte solutions used as analogues. There has been minimal scientific study to confirm these anecdotal observations, however. The present study determines the apparent solubility product for gibbsite in 50 tank samples. The ratio of hydroxide to aluminum in the liquid phase for the samples is calculated and plotted as a function of total sodium molarity. Total sodium molarity is used as a surrogate for ionic strength, because the relative ratios of mono, di and trivalent anions are not available for all of the samples. These results were compared to the simple NaOH-NaAl(OH{sub 4})H{sub 2}O system, and the NaOH-NaAl(OH{sub 4})NaCl-H{sub 2}O system data retrieved from the literature. The results show that gibbsite is apparently more soluble in the samples than in the simple systems whenever the sodium molarity is greater than two. This apparent enhanced solubility cannot be explained solely by differences in ionic strength. The change in solubility with ionic strength in simple systems is …
Date: June 20, 2012
Creator: JG, REYNOLDS
Object Type: Article
System: The UNT Digital Library
APPLICATION OF COLUMN EXTRACTION METHOD FOR IMPURITIES ANALYSIS ON HB-LINE PLUTONIUM OXIDE IN SUPPORT OF MOX FEED PRODUCT SPECIFICATIONS (open access)

APPLICATION OF COLUMN EXTRACTION METHOD FOR IMPURITIES ANALYSIS ON HB-LINE PLUTONIUM OXIDE IN SUPPORT OF MOX FEED PRODUCT SPECIFICATIONS

The current mission at H-Canyon involves the dissolution of an Alternate Feedstocks 2 (AFS-2) inventory that contains plutonium metal. Once dissolved, HB-Line is tasked with purifying the plutonium solution via anion exchange, precipitating the Pu as oxalate, and calcining to form plutonium oxide (PuO{sub 2}). The PuO{sub 2} will provide feed product for the Mixed Oxide (MOX) Fuel Fabrication Facility, and the anion exchange raffinate will be transferred to H-Canyon. The results presented in this report document the potential success of the RE resin column extraction application on highly concentrated Pu samples to meet MOX feed product specifications. The original 'Hearts Cut' sample required a 10000x dilution to limit instrument drift on the ICP-MS method. The instrument dilution factors improved to 125x and 250x for the sample raffinate and sample eluent, respectively. As noted in the introduction, the significantly lower dilutions help to drop the total MRL for the analyte. Although the spike recoveries were half of expected in the eluent for several key elements, they were between 94-98% after Nd tracer correction. It is seen that the lower ICD limit requirements for the rare earths are attainable because of less dilution. Especially important is the extremely low Ga limit …
Date: March 20, 2012
Creator: Jones, M.; Diprete, D. & Wiedenman, B.
Object Type: Report
System: The UNT Digital Library
Assessment and Mitigation of Diagnostic-Generated Electromagnetic Interference at the National Ignition Facility (open access)

Assessment and Mitigation of Diagnostic-Generated Electromagnetic Interference at the National Ignition Facility

Electromagnetic interference (EMI) is an ever-present challenge at laser facilities such as the National Ignition Facility (NIF). The major source of EMI at such facilities is laser-target interaction that can generate intense electromagnetic fields within, and outside of, the laser target chamber. In addition, the diagnostics themselves can be a source of EMI, even interfering with themselves. In this paper we describe EMI generated by ARIANE and DIXI, present measurements, and discuss effects of the diagnostic-generated EMI on ARIANE's CCD and on a PMT nearby DIXI. Finally we present some of the efforts we have made to mitigate the effects of diagnostic-generated EMI on NIF diagnostics.
Date: April 20, 2012
Creator: Brown, C. G.; Ayers, M. J.; Felker, B.; Ferguson, W.; Holder, J P; Nagel, S. R. et al.
Object Type: Article
System: The UNT Digital Library
Asynchronous Checkpoint Migration with MRNet in the Scalable Checkpoint / Restart Library (open access)

Asynchronous Checkpoint Migration with MRNet in the Scalable Checkpoint / Restart Library

Applications running on today's supercomputers tolerate failures by periodically saving their state in checkpoint files on stable storage, such as a parallel file system. Although this approach is simple, the overhead of writing the checkpoints can be prohibitive, especially for large-scale jobs. In this paper, we present initial results of an enhancement to our Scalable Checkpoint/Restart Library (SCR). We employ MRNet, a tree-based overlay network library, to transfer checkpoints from the compute nodes to the parallel file system asynchronously. This enhancement increases application efficiency by removing the need for an application to block while checkpoints are transferred to the parallel file system. We show that the integration of SCR with MRNet can reduce the time spent in I/O operations by as much as 15x. However, our experiments exposed new scalability issues with our initial implementation. We discuss the sources of the scalability problems and our plans to address them.
Date: March 20, 2012
Creator: Mohror, K.; Moody, A. & de Supinski, B. R.
Object Type: Article
System: The UNT Digital Library
Award ER25844: Minimizing System Noise Effects for Extreme-Scale Scientific Simulation Through Function Delegation (open access)

Award ER25844: Minimizing System Noise Effects for Extreme-Scale Scientific Simulation Through Function Delegation

In software running on distributed computing clusters, time spent on communication between nodes in the cluster can be a significant portion of the overall computation time; background operating system tasks and other computational �noise� on the nodes of the system can have a significant impact on the amount of time this communication takes, especially on large systems. The research completed in this period has improved understanding of when such noise will have a significant impact. Specifically, it was demonstrated that not just noise on the nodes, but also noise on the network between nodes can have a significant impact on computation time. It was also demonstrated that noise patterns matter more than noise intensity: very regular noise can cause less disruption than lighter (on average) but less regular noise. It was also demonstrated that the effect of noise is more prominent as the speed of the network between nodes is increased. Furthermore, a tracing tool, Netgauge, was improved via our work, and a system simulator, LogGOPSim, was developed; they can be used by application developers to improve performance of their program and by system designers to mitigate the effects of noise by adjusting the noise characteristics of the operating system. …
Date: November 20, 2012
Creator: Lumsdaine, Andrew
Object Type: Report
System: The UNT Digital Library
Beam Experiments Towards High-Intensity Beams in RHIC (open access)

Beam Experiments Towards High-Intensity Beams in RHIC

Proton bunch intensities in RHIC are planned to be increased from 2 {center_dot} 10{sup 11} to 3 {center_dot} 10{sup 11} protons per bunch to increase the luminosity, together with head-on beam-beam compensation using electron lenses. To study the feasibility of the intensity increase, beam experiments are being performed. Recent experimental results are presented.
Date: May 20, 2012
Creator: Montag, C.; Ahrens, L.; Brennan, J. M.; Blaskiewicz, M.; Drees, A.; Fischer, W. et al.
Object Type: Article
System: The UNT Digital Library
Beam optics and the pp2pp experiment at RHIC (open access)

Beam optics and the pp2pp experiment at RHIC

The newly installed forward detector system at the STAR experiment at RHIC measures small angle elastic and inelastic scattering of polarized protons on polarized protons. The detector system makes use of a pair of Roman Pot (RP) detectors, instrumented with silicon detectors, and located on either side of the STAR intersection region downstream of the DX and D0 dipoles and quadrupole triplets. The parallel to point optics is designed so that scattering angles are determined from position measurements at the RP's with small error. The RP setup allows measurement of position and angle for a subset of the scattered protons. With this position/angle correlations at the RP's can be compared with optics model predictions to get a measure of the accuracy of the quadrupole triplet current settings. The current in each quadrupole in the triplets is comprised of sums and differences of up to six power supplies and an overall 1% error in the triplet field strengths results in a 4% error in four-momentum transfer squared. This technique is also useful to check the polarity of the skew elements located in each quadrupole triplet. Results of the analysis will be presented.
Date: May 20, 2012
Creator: H., Pile P.; Guryn, W.; Lee, J. H.; Tepikian, S. & Yip, K.
Object Type: Article
System: The UNT Digital Library
Benchmarking a New Closed-Form Thermal Analysis Technique Against a Traditional Lumped Parameter, Finite-Difference Method (open access)

Benchmarking a New Closed-Form Thermal Analysis Technique Against a Traditional Lumped Parameter, Finite-Difference Method

A benchmarking effort was conducted to determine the accuracy of a new analytic generic geology thermal repository model developed at LLNL relative to a more traditional, numerical, lumped parameter technique. The fast-running analytical thermal transport model assumes uniform thermal properties throughout a homogenous storage medium. Arrays of time-dependent heat sources are included geometrically as arrays of line segments and points. The solver uses a source-based linear superposition of closed form analytical functions from each contributing point or line to arrive at an estimate of the thermal evolution of a generic geologic repository. Temperature rise throughout the storage medium is computed as a linear superposition of temperature rises. It is modeled using the MathCAD mathematical engine and is parameterized to allow myriad gridded repository geometries and geologic characteristics [4]. It was anticipated that the accuracy and utility of the temperature field calculated with the LLNL analytical model would provide an accurate 'birds-eye' view in regions that are many tunnel radii away from actual storage units; i.e., at distances where tunnels and individual storage units could realistically be approximated as physical lines or points. However, geometrically explicit storage units, waste packages, tunnel walls and close-in rock are not included in the MathCAD …
Date: August 20, 2012
Creator: Huff, K. D. & Bauer, T. H. (Nuclear Engineering Division)
Object Type: Report
System: The UNT Digital Library
Bunch compressor design for potential FEL operation at eRHIC (open access)

Bunch compressor design for potential FEL operation at eRHIC

N/A
Date: May 20, 2012
Creator: Y., Jing; Hao, Y. & Litvinenko, V.
Object Type: Article
System: The UNT Digital Library
Calculation of synchrotron radiation from high intensity electron beam at eRHIC (open access)

Calculation of synchrotron radiation from high intensity electron beam at eRHIC

The Electron-Relativistic Heavy Ion Collider (eRHIC) at Brookhaven National Lab is an upgrade project for the existing RHIC. A 30 GeV energy recovery linac (ERL) will provide a high charge and high quality electron beam to collide with proton and ion beams. This will improve the luminosity by at least 2 orders of magnitude. The synchrotron radiation (SR) from the bending magnets and strong quadrupoles for such an intense beam could be penetrating the vacuum chamber and producing hazards to electronic devices and undesired background for detectors. In this paper, we calculate the SR spectral intensity, power density distributions and heat load on the chamber wall. We suggest the wall thickness required to stop the SR and estimate spectral characteristics of the residual and scattered background radiation outside the chamber.
Date: May 20, 2012
Creator: Y., Jing; Chubar, O. & Litvinenko, V.
Object Type: Article
System: The UNT Digital Library