789 research outputs found
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EXTENSION OF THE 1D FOUR-GROUP ANALYTIC NODAL METHOD TO FULL MULTIGROUP
In the mid 80’s, a four-group/two-region, entirely analytical 1D nodal benchmark appeared. It was readily acknowledged that this special case was as far as one could go in terms of group number and still achieve an analytical solution. In this work, we show that by decomposing the solution to the multigroup diffusion equation into homogeneous and particular solutions, extension to any number of groups is a relatively straightforward exercise using the mathematics of linear algebra
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Some recent developments in treatment planning software and methodology for BNCT
Over the past several years the Idaho National Engineering Laboratory (INEL) has led the development of a unique, internationally-recognized set of software modules (BNCT-rtpe) for computational dosimetry and treatment planning for Boron Neutron Capture Therapy (BNCT). The computational capability represented by this software is essential to the proper administration of all forms of radiotherapy for cancer. Such software addresses the need to perform pretreatment computation and optimization of the radiation dose distribution in the target volume. This permits the achievement of the optimal therapeutic ratio (tumor dose relative to critical normal tissue dose) for each individual patient via a systematic procedure for specifying the appropriate irradiation parameters to be employed for a given treatment. These parameters include angle of therapy beam incidence, beam aperture and shape, and beam intensity as a function of position across the beam front. The INEL software is used for treatment planning in the current series of human glioma trials at Brookhaven National Laboratory (BNL) and has also been licensed for research and developmental purposes to several other BNCT research centers in the US and in Europe
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VERIFICATION OF THE INL/COMBINE7 NEUTRON ENERGY SPECTRUM CODE
We construct semi-analytic benchmarks for the neutron slowing down equations in the thermal, resonance and fast energy regimes through mathematical embedding. The method features a fictitious time-dependent slowing down equations solved via Taylor series expansion over discrete “time” intervals. Two classes of benchmarks are considered- the first treats methods of solution and the second the multigroup approximation itself. We present several meaningful benchmark methods comparisons with the COMBINE7 energy spectrum code and a simple demonstration of convergence of the multigroup approximation
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Providing Nuclear Criticality Safety Analysis Education through Benchmark Experiment Evaluation
One of the challenges that today's new workforce of nuclear criticality safety engineers face is the opportunity to provide assessment of nuclear systems and establish safety guidelines without having received significant experience or hands-on training prior to graduation. Participation in the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and/or the International Reactor Physics Experiment Evaluation Project (IRPhEP) provides students and young professionals the opportunity to gain experience and enhance critical engineering skills
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A NEW SINGLE-CRYSTAL FILTERED THERMAL NEUTRON SOURCE FOR NEUTRON CAPTURE THERAPY RESEARCH AT THE UNIVERSITY OF MISSOURI
Parameter studies, design calculations and initial neutronic performance measurements have been completed for a new thermal neutron beamline to be used for neutron capture therapy cell and small-animal radiobiology studies at the University of Missouri Research Reactor. The beamline features the use of single-crystal silicon and bismuth sections for neutron filtering and for reduction of incident gamma radiation. The calculated and measured thermal neutron flux produced at the irradiation location is on the order of 9.5x108 neutrons/cm2-s, with a measured cadmium ratio (Au foils) of 105, indicating a well-thermalized spectrum
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Preliminary Measurements From A New Flat Plate Facility For Aerodynamic Research
This paper details the design and preliminary measurements used in the characterisation of a new flat plate research facility. The facility is designed specifically to aid in the understanding of entropy generation throughout the boundary layer with special attention given to non-equilibrium flows. Hot-wire measurements were obtained downstream of two turbulence generating grids. The turbulence intensity, integral and dissipation length scale ranges measured are 1.6%-7%, 5mm-17mm and 0.7mm-7mm, respectively. These values compared well to existing correlations. The flow downstream of both grids was found to be homogenous and isotropic. Flow visualisation is employed to determine aerodynamic parameters such as flow 2-dimensionality and the effect of the flap angle on preventing separation at the leading edge. The flow was found to be 2-dimensional over all measurement planes. The non-dimensional pressure distribution of a modern turbine blade suction surface is simulated on the flat plate through the use of a variable upper wall. The Reynolds number range based on wetted plate length and inlet velocity is 70,000-4,000,000
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Performance of a New Composite Single-Crystal Filtered Thermal Neutron Beam for Neutron Capture Therapy Research at the University of Missouri
The University of Missouri (MU) Institute for Nano and Molecular Medicine, the Idaho National Laboratory (INL) and the University of Missouri Research Reactor (MURR) have undertaken a new collaborative research initiative to further the development of improved boron delivery agents for BNCT. The first step of this effort has involved the design and construction of a new thermal neutron beam irradiation facility for cell and small-animal radiobological research at the MURR. In this paper we present the beamline design with the results of pertinent neutronic design calculations. Results of neutronic performance measurements, initiated in February 2008, will also be available for inclusion in the final paper. The new beam will be located in an existing 152.4 mm (6’) diameter MURR beam tube extending from the core to the right in Figure 1. The neutron beam that emanates from the berylium reflector around the reactor is filtered with single-crystal silicon and single-crystal bismuth segments to remove high energy, fission spectrum neutrons and reactor gamma ray contamination. The irradiation chamber is downstream of the bismuth filter section, and approximately 3.95 m from the central axis of the reactor. There is sufficient neutron flux available from the MURR at its rated power of 10 MW to avoid the need for cryogenic cooling of the crystals. The MURR operates on average 150 hours per week, 52 weeks a year. In order to take advantage of 7800 hours of operation time per year the small animal BNCT facility will incorparate a shutter constucuted of boral, lead, steel and polyethylene that will allow experimenters to access the irradiation chamber a few minutes after irradiation. Independent deterministic and stochastic models of the coupled reactor core and beamline were developed using the DORT two-dimensional radiation transport code and the MCNP-5 Monte Carlo code, respectively. The BUGLE-80 47-neutron, 20-gamma group cross section library was employed for the DORT computations, in keeping with previous practice for analysis of a number of other NCT neutron facilities worldwide. The standard ENDF/B Version 6.8 cross section libraries were used with MCNP, except that special calculated cross section sets for the single-crystal bismuth and silicon filters in the MCNP calculations were provided to MU and INL specifically for this study by the Korean Atomic Energy Research Institute and, independently, by North Carolina State University. Cross sections for the amorphous bismuth and silicon files on the BUGLE-80 library used with DORT were modified to account for the single-crystal form of these materials using correction factors computed using MCNP. A number of parameter studies were conducted, independently varying the thicknesses of the silicon and bismuth filter sections to find an optimum that maximizes the thermal neutron flux while maintaining the fast-neutron and gamma components of the beam within acceptable ranges. Both the DORT and MCNP beamline optimization computations led to the conclusion that the silicon filtering section should be approximately 55 cm in thickness and the bismuth section should be 8 cm in thickness. The total estimated thermal neutron flux delivered to the irradiation location by the filtered beam, integrated to 0.414 eV, is approximately 9.0 x 108 neutrons/cm2-s. The calculations also yielded an epithermal and fast-neutron kerma of approximately 1.0 x 10-11 cGy-cm2
A novel TPR-BEN domain interaction mediates PICH-BEND3 association
PICH is a DNA translocase required for the maintenance of chromosome stability in human cells. Recent data indicate that PICH co-operates with topoisomerase IIα to suppress pathological chromosome missegregation through promoting the resolution of ultra-fine anaphase bridges (UFBs). Here, we identify the BEN domain-containing protein 3 (BEND3) as an interaction partner of PICH in human cells in mitosis. We have purified full length PICH and BEND3 and shown that they exhibit a functional biochemical interaction in vitro. We demonstrate that the PICH-BEND3 interaction occurs via a novel interface between a TPR domain in PICH and a BEN domain in BEND3, and have determined the crystal structure of this TPR-BEN complex at 2.2 Å resolution. Based on the structure, we identified amino acids important for the TPR-BEN domain interaction, and for the functional interaction of the full-length proteins. Our data reveal a proposed new function for BEND3 in association with PICH, and the first example of a specific protein-protein interaction mediated by a BEN domain
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INL Capabilities For Nuclear Data Measurements Using The Argonne Intense Pulsed Neutron Source Facility
The relevant facts concerning the Argonne National Laboratory – Intense Pulsed Neutron Source (ANL/IPNS) and the Idaho National Laboratory (INL) apparatus for use at the ANL/IPNS facility to measure differential neutron interaction cross sections of interest for advanced reactor physics applications are presented. The INL apparatus, which consists of an array of multiple types of multiple detectors operated in coincidence, signal electronics, and a data acquisition system, is presented as an application of new means and methods to measure the relevant parameters described. The immediate measurement goals involve measurement of neutron induced interaction cross sections for 240Pu and 242Pu with 241Pu, 241Am, with measurements for other nuclides of interest for advanced reactor physics applications to follow later. Specific uncertainties and error limits are presented and methods for controlling these uncertainties are described. The post experiment analysis using data sorts and data selection from a large, self-consistent data set to produce spectra that will be analyzed for direct results and used to determine cross sections is also discussed
Recommended from our members
Some recent developments in treatment planning software and methodology for BNCT
Over the past several years/the Idaho National Engineering Laboratory (INEL) has led the development of a unique, internationally-recognized set of software modules (BNCT rtpe) for computational dosimetry and treatment planning for Boron Neutron Capture Therapy (BNCT). The computational capability represented by this software is essential to the proper administration of all forms of radiotherapy for cancer. Such software addresses the need to perform pretreatment computation and optimization of the radiation dose distribution in the target volume. This permits the achievement of the optimal therapeutic ratio (tumor dose relative to critical normal tissue dose) for each individual patient via a systematic procedure for specifying the appropriate irradiation parameters to be employed for a given treatment. These parameters include angle of therapy beam incidence, beam aperture and shape,and beam intensity as a function of position across the beam front. The INEL software is used for treatment planning in the current series of human glioma trials at Brookhaven National Laboratory (BNL) and has also been licensed for research and developmental purposes to several other BNCT research centers in the US and in Europe
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