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Neutron beam irradiation study of workload dependence of SER in a microprocessor

Description: It is known that workloads are an important factor in soft error rates (SER), but it is proving difficult to find differentiating workloads for microprocessors. We have performed neutron beam irradiation studies of a commercial microprocessor under a wide variety of workload conditions from idle, performing no operations, to very busy workloads resembling real HPC, graphics, and business applications. There is evidence that the mean times to first indication of failure, MTFIF defined in Section II, may be different for some of the applications.
Date: January 1, 2009
Creator: Michalak, Sarah E; Graves, Todd L; Hong, Ted; Ackaret, Jerry; Sonny, Rao; Subhasish, Mitra et al.
Partner: UNT Libraries Government Documents Department

Conceptual Design of a Rapid-Cycling Synchrotron for the KFA-Juelich Spallation Neutron Source

Description: An accelerator group was established at ANL by the request of KFA-Juelich to carry out a conceptual design study and cost estimate for a rapid-cycling synchrotron as a possible first stage program on spallation neutron sources at KFA-Juelich. This set of notes is the individual notes which form the basis of the final report under this proposal prepared in January 1983. This document contains 37 papers/notes for Advanced Accelerator Development - Neutron Source Series Notes...numbered AAD-N-1 through AAD-N-37. Each note or paper is written by various authors.
Date: January 1983
Creator: ANL-KFA Study Group
Partner: UNT Libraries Government Documents Department


Description: The program of neutron activation analysis service at Oak Ridge National Laboratory is described. The techniques used, the limits of measurement, and the general applications of the method are discussed. (T.R.H.)
Date: July 22, 1958
Creator: Leddicotte, G.W. & Reynolds, S.A.
Partner: UNT Libraries Government Documents Department

A workshop on enhanced national capability for neutron scattering

Description: This two-day workshop will engage the international neutron scattering community to vet and improve the Lujan Center Strategic Plan 2007-2013 (SP07). Sponsored by the LANL SC Program Office and the University of California, the workshop will be hosted by LANSCE Professor Sunny Sinha (UCSD). Endorsement by the Spallation Neutron Source will be requested. The discussion will focus on the role that the Lujan Center will play in the national neutron scattering landscape assuming full utilization of beamlines, a refurbished LANSCE, and a 1.4-MW SNS. Because the Lujan Strategic Plan is intended to set the stage for the Signature Facility era at LANSCE, there will be some discussion of the long-pulse spallation source at Los Alamos. Breakout groups will cover several new instrument concepts, upgrades to present instruments, expanded sample environment capabilities, and a look to the future. The workshop is in keeping with a request by BES to update the Lujan strategic plan in coordination with the SNS and the broader neutron community. Workshop invitees will be drawn from the LANSCE User Group and a broad cross section of the US, European, and Pacific Rim neutron scattering research communities.
Date: January 1, 2009
Creator: Hurd, Alan J; Rhyne, James J & Lewis, Paul S
Partner: UNT Libraries Government Documents Department

Neutron Beams from Deuteron Breakup at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory

Description: Accelerator-based neutron sources offer many advantages, in particular tunability of the neutron beam in energy and width to match the needs of the application. Using a recently constructed neutron beam line at the 88-Inch Cyclotron at LBNL, tunable high-intensity sources of quasi-monoenergetic and broad spectrum neutrons from deuteron breakup are under development for a variety of applications.
Date: July 31, 2007
Creator: McMahan, M.A.; Ahle, L.; Bleuel, D.L.; Bernstein, L.; Braquest, B.R.; Cerny, J. et al.
Partner: UNT Libraries Government Documents Department

Lattice dynamics of LuPO{sub 4}

Description: Lutetium orthophosphate is an important nonmagnetic host material for rare-earth-activated luminescence applications. We have measured the LuPO{sub 4} phonon density of states and dispersion curves along the [{xi}00],[{xi}{xi}0], and [00{xi}] symmetry directions by neutron spectroscopy using polycrystalline and single-crystal samples. A quantitative analysis of the neutron results was carried out using a lattice-dynamical shell model.
Date: June 1996
Creator: Nipko, J. C.; Loong, C.-K.; Loewenhaupt, M.; Reichardt, W.; Braden, M. & Boatner, L. A.
Partner: UNT Libraries Government Documents Department

Detector array design

Description: Neutron scattering facility at Oak-Ridge National is used to measure residual stresses in many different materials. Neutron beam from the reactor can be used to penetrate the inner atomic distances of metals which then can be diffracted to a detector to measure the strain. The strain data later can be converted to stresses. The facility currently uses only one detector to carry the measurement. By designing an array of detectors data can be obtained at a much faster rate and or having a much better and improved resolution. The purpose of this report is to show design of such array of detectors and their movements (rotation) for possible maximum data collection at a faster rate.
Date: February 1, 1996
Creator: Lari, S.
Partner: UNT Libraries Government Documents Department

Variational correction to the FERMI beam solution

Description: We consider the time-independent, monoenergetic searchlight problem for a purely scattering, homogeneous slab with a pencil beam of nuclear particles impinging upon one surface. The scattering process is assumed sufficiently peaked in the forward direction so that the Fokker-Planck differential scattering operator can be used. Further, the slab is assumed sufficiently thin so that backscattering is negligibly small. Generally, this problem is approximated by the classic Fermi solution. A number of modifications of Fermi theory, aiming at improved accuracy, have been proposed. Here, we show that the classic Fermi solution (or any approximate solution) can I be improved via a variational formalism.
Date: October 1, 1996
Creator: Su, Bingjing & Pomraning, G.C.
Partner: UNT Libraries Government Documents Department

The structure of carbon black-elastomer composites by small-angle neutron scattering and the method of contrast variation

Description: We have been exploring the use of small-angle neutron scattering and the method of contrast variation to give a new look at a very old problem: reinforcement of elastomers by carbon black in durable rubber products. Carbon black has a hierarchy of structures consisting of particles covalently bound into aggregates, which in turn associate by weak interactions into agglomerates. We found that in one carbon black, HSA, the aggregates are rodlike, containing an average of 4-6 particles. The aggregates have an outer graphitic shell and an inner core of lower density carbon. The core is continuous throughout the carbon black aggregate. Contrast variation of swollen HSA-polyisoprene gels shows that the HSA is completely embedded in polyisoprene and that the agglomerates are formed predominantly by end on associations of the rodlike aggregates. The surface structure of the carbon black appears smooth over length scales above about 10 {angstrom}. Further studies using production carbon blacks suggest that these structural characteristics are generally present in commercial rubber composites.
Date: July 1, 1996
Creator: Hjelm, R.P.; Wampler, W. & Gerspacher, M.
Partner: UNT Libraries Government Documents Department

Radiation-induced segregation in alloy X-750

Description: Microstructural and microchemical evolution of an Alloy X-750 heat under neutron irradiation was studied in order to understand the origin of irradiation-assisted stress corrosion cracking. Both clustering of point defects and radiation-induced segregation at interfaces were observed. Although no significant changes in the precipitate structure were observed, boundaries exhibited additional depletion of Cr and Fe and enrichment of Ni.
Date: December 31, 1996
Creator: Kenik, E.A.
Partner: UNT Libraries Government Documents Department

Study on severe accident fuel dispersion behavior in the Advanced Neutron Source reactor at Oak Ridge National Laboratory

Description: Core flow blockage events are a leading contributor to core damage initiation risk in the Advanced Neutron Source (ANS) reactor. During such an accident, insufficient cooling of the fuel could result in core heatup and melting under full coolant flow condition. Coolant inertia forces acting on the melt surface would likely break up the melt into small particles. Under thermal-hydraulic conditions of ANS coolant channel, micro-fine melt particles are expected. Heat transfer between melt particle and coolant, which affects particle breakup, was studied. The study indicates that the thermal effect on melt fragmentation seems to be negligible because the time corresponding to the breakup due to hydrodynamic forces is much shorter than the time for the melt surface to solidify. The study included modeling and analyses to predict transient behavior and transport of debris particles throughout the coolant system. The transient model accounts for the surface forces acting on the particle that results from the pressure variation on the surface, inertia, virtual mass, viscous force due to relative motion of particle in the coolant, gravitation, and resistance due to inhomogenous coolant velocity radially across piping due to possible turbulent coolant motions. Results indicate that debris particles would reside longest in heat exchangers because of lower coolant velocity there. Also core debris tends to move together upon melting and entrainment.
Date: December 31, 1995
Creator: Kim, S.H.; Taleyarkhan, R.P.; Navarro-Valenti, S.; Georgevich, V. & Xiang, J.Y.
Partner: UNT Libraries Government Documents Department

Status Report on the Spallation Neutron Source

Description: The purpose of the Spallation Neutron Source Project (SNS) is to generate low-energy neutrons (ambient [{approximately}200 meV] and cold [{approximately}50 meV]) which can be used by up to 18 neutron beam lines to study the structure and functionality of materials. The neutrons are generated by the spallation process initiated by the interactions of 1-GeV protons with a Hg target. These neutrons are reflected by a Pb reflector and are moderated by 2 water (ambient) and 2 super critical hydrogen (cryogenic) moderators. The pulse structure for the 1 MW proton beam is 60 Hertz and < 0.7 {micro}s/pulse. The facility must be upgradable to higher power levels (2- and 4- MW) with minimal operational interruptions. Although not included in the current funding or baseline, a second target station and associated support structure which will be designed to utilize cold neutrons is also considered to be an upgrade that must be incorporated with minimal impact on operations.
Date: October 12, 1998
Creator: Gabriel, T.A.
Partner: UNT Libraries Government Documents Department

Validation of computational methods for treatment planning of fast-neutron therapy using activation foil techniques

Description: A closed-form direct method for unfolding neutron spectra from foil activation data is presented. The method is applied to measurements of the free-field neutron spectrum produced by the proton-cyclotron-based fast-neutron radiotherapy facility at the University of Washington (UW) School of Medicine. The results compare favorably with theoretical expectations based on an a-priori calculational model of the target and neutron beamline configuration of the UW facility.
Date: December 1, 1997
Creator: Nigg, D.W.; Wemple, C.A.; Hartwell, J.K.; Harker, Y.D.; Venhuizen, J.R. & Risler, R.
Partner: UNT Libraries Government Documents Department

High performance X-ray and neutron microfocusing optics. Phase II final report.

Description: The use of extremely small diameter x-ray beams at synchrotron radiation facilities has become an important experimental technique for investigators in many other scientific disciplines. While there have been several different optical elements developed for producing such microbeams, this SBIR project was concerned with one particular device: the tapered-monocapillary optic.
Date: January 14, 2000
Creator: Hirsch, Gregory
Partner: UNT Libraries Government Documents Department

Chemistry and Physics Challenges in Spallation Neutron Source Safety Analyses

Description: The SNS is a Department of Energy (DOE) research facility under construction near Oak Ridge, Tennessee. The SNS includes a 300-m long, 1 GeV, 2 MW, linear accelerator that produces neutrons by collisions of high-energy protons with mercury target nuclei. The mercury target atoms are in a circulating mercury loop that is water-cooled. The mercury loop operates at a nominal average temperature of 75 C (60 C nominal cold leg temperature and 90 C nominal hot leg temperature). The overall target system also includes circulating fluid systems for supercritical cryogenic hydrogen (to moderate product neutrons to low energy), heavy water (for cooling of shielding), and several light water systems (for shielding cooling, proton beam window and neutron beam window cooling, and to moderate neutrons to energies higher than those from the cryogenic hydrogen moderator).
Date: June 13, 2001
Creator: Lowrie, RR
Partner: UNT Libraries Government Documents Department

Accelerators for cancer therapy

Description: The vast majority of radiation treatments for cancerous tumors are given using electron linacs that provide both electrons and photons at several energies. Design and construction of these linacs are based on mature technology that is rapidly becoming more and more standardized and sophisticated. The use of hadrons such as neutrons, protons, alphas, or carbon, oxygen and neon ions is relatively new. Accelerators for hadron therapy are far from standardized, but the use of hadron therapy as an alternative to conventional radiation has led to significant improvements and refinements in conventional treatment techniques. This paper presents the rationale for radiation therapy, describes the accelerators used in conventional and hadron therapy, and outlines the issues that must still be resolved in the emerging field of hadron therapy.
Date: June 23, 2000
Creator: Lennox, Arlene J.
Partner: UNT Libraries Government Documents Department

Optimizing a three-element core design for the Advanced Neutron Source Reactor

Description: Source of neutrons in the proposed Advanced Neutron Source facility is a multipurpose research reactor providing 5-10 times the flux, for neutron beams, of the best existing facilities. Baseline design for the reactor core, based on the ``no new inventions`` rule, was an assembly of two annular fuel elements similar to those used in the Oak Ridge and Grenoble high flux reactors, containing highly enriched U silicide particles. DOE commissioned a study of the use of medium- or low-enriched U; a three-element core design was studied as a means to provide extra volume to accommodate the additional U compound required when the fissionable {sup 235}U has to be diluted with {sup 238}U to reduce the enrichment. This paper describes the design and optimization of that three-element core.
Date: December 31, 1995
Creator: West, C.D.
Partner: UNT Libraries Government Documents Department