130 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Neutrons"  
Results: 1 - 24 next
open access

Position-sensitive detection of slow neutrons: Survey of fundamental principles

Description: This paper sets forth the fundamental principles governing the development of position-sensitive detection systems for slow neutrons. Since neutrons are only weakly interacting with most materials, it is not generally practical to detect slow neutrons directly. Therefore all practical slow neutron detection mechanisms depend on the use of nuclear reactions to convert'' the neutron to one or more charged particles, followed by the subsequent detection of the charged particles. The different conv… more
Date: January 1, 1992
Creator: Crawford, R.K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Code validation with EBR-II test data

Description: An extensive system of computer codes is used at Argonne National Laboratory to analyze whole-plant transient behavior of the Experimental Breeder Reactor 2. Three of these codes, NATDEMO/HOTCHAN, SASSYS, and DSNP have been validated with data from reactor transient tests. The validated codes are the foundation of safety analyses and pretest predictions for the continuing design improvements and experimental programs in EBR-II, and are also valuable tools for the analysis of innovative reactor … more
Date: January 1, 1992
Creator: Herzog, J.P.; Chang, L.K.; Dean, E.M.; Feldman, E.E.; Hill, D.J.; Mohr, D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Testing and COBRA-SFS analysis of the VSC-17 ventilated concrete, spent fuel storage cask

Description: A performance test of a Pacific Sierra Nuclear VSC-17 ventilated concrete storage cask loaded with 17 canisters of consolidated PWR spent fuel generating approximately 15 kW was conducted. The performance test included measuring the cask surface, concrete, air channel surface, and fuel temperatures, as well as cask surface gamma and neutron dose rates. Testing was performed using vacuum, nitrogen, and helium backfill environments. Pretest predictions of cask thermal performance were made using … more
Date: April 1, 1992
Creator: McKinnon, M.A.; Dodge, R.E. (Pacific Northwest Lab., Richland, WA (United States)) & Schmitt, R.C. (EG and G Idaho, Inc., Idaho Falls, ID (United States))
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Comparison of fracture behavior for low-swelling ferritic and austenitic alloys irradiated in the Fast Flux Test Facility (FFTF) to 180 DPA

Description: Fracture toughness testing was conducted to investigate the radiation embrittlement of high-nickel superalloys, modified austenitic steels and ferritic steels. These materials have been experimentally proven to possess excellent resistance to void swelling after high neutron exposures. In addition to swelling resistance, post-irradiation fracture resistance is another important criterion for reactor material selection. By means of fracture mechanics techniques the fracture behavior of those hig… more
Date: February 1, 1992
Creator: Huang, F.H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Convergence of the multiple scattering expansion in XAFS and XANES

Description: The convergence of the multiple-scattering expansion of XAFS and XANES by explicit path-bypath calculations. The approach is based on the fast scattering matrix formalism of Rehr and Albers, together with an automated path finder and filters that exclude negligible paths. High-order scattering terms are found to be essential, especially at low energies. Several factors including the magnitude of curved wave scattering amplitudes, inelastic losses and multiple-scattering Debye-Waller factors con… more
Date: January 1, 1992
Creator: Rehr, J.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Enhancement of the epithermal neutron beam at the Brookhaven Medical Research Reactor

Description: Improvements for the Brookhaven Medical Research Reactor (BMRR) epithermal neutron beam have been evaluated by MCNP calculations and measurements. Different dosimetric measurements have been made after one fuel element was in place of the graphite stringer in the core. Measurements show an 18% increase of beam intensity without reducing the beam quality. These results are consistent with the predictions of an MCNP calculation. Major changes to enhance the beam include rearranging the fuel eleme… more
Date: January 1, 1992
Creator: Liu, Hungyuan B.; Brugger, R. M. & Rorer, D. C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Experiments on the nuclear interactions of pions and electrons. [Dept. of Physics, Univ. of Virginia]

Description: The analysis of the deuterium content in the CD target used in an experiment to study the [pi] + d [yields] 2p reaction at incident pion energies from 4 to 20 MeV was completed. The final paper describing this experiment will be submitted for publication this summer. Analysis of LAMPF Exp. on pion absorption in [sup 4]He is continuing. In 1991, we collaborated with D. Pocanic from the Univ. of Virginia on a measurement at LAMPF of the [pi][sup 0] production in [pi] + p interactions. This run pr… more
Date: August 1, 1992
Creator: Minehart, R.C. & Ziock, K.O.H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Experiments With Energetic μ-d and μ-t Emitted From Solid Hydrogen

Description: A set of experiments is reviewed which makes use of the emission of muonic deuterium from the surface of a layer of solid hydrogen. The behavior of muons in a solid target system has been studied via detection of muon decay electrons, muonic x-rays, and fusion products (neutrons and charged particles). The emission of muonic deuterium is understood to result from the Ramsauer-Townsend scattering minimum. The energy distribution of the emitted atoms ranges from tenths of eV to about 10eV, and ca… more
Date: January 1, 1992
Creator: Marshall, G. M.; Beveridge, J. L.; Bailey, J. M.; Beer, G. A.; Knowles, P. E.; Mason, G. R. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Characterization of porosity via secondary reactions

Description: The new TPD-MS/TGA system has been constructed and successfully tested. This system is constructed around a new Cahn D-200 digital recording microbalance, which was purchased for this purpose. The TPD reactor is the hangdown'' tube for the microbalance. The system can operate at pressures from vacuum to atmospheric. Control and data logging of this new experimental system are performed using a Macintosh II microcomputer with a GW Instruments 625 Jr. interface. All the control software has been … more
Date: January 1, 1992
Creator: Calo, J.M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Gadolinium as an Element for Neutron Capture Therapy

Description: At BNL, preparations are being made to test in vitro compounds containing Gd and compare their response to the response of GD-DTPA to determine if one or several compounds can be located that enter the cells and enhance the Auger effect. Two similar rotators with positions for cell vials that have been constructed for these tests. The first rotator is made of only paraffin which simulates healthy tissue and provides control curves. The second rotator has 135 ppM of Gd-157 in the paraffin to sim… more
Date: January 1, 1992
Creator: Brugger, Robert M.; Liu, Hungyuan B.; Laster, Brenda H.; Gordon, Christopher R.; Greenberg, Dennis D. & Warkentien, Lynne S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The Weak Decay of Helium Hypernuclei

Description: A [Lambda] hyperon replaces a neutron in a nucleus to form a hypernucleus via the [sup A]X(K[sup [minus]], [pi][sup [minus]]) [sub [Lambda]][sup A]X reaction at 750 MeV/c (Brookhaven Experiment 788). The free [Lambda] decay rates [Gamma]([Lambda] [yields] p[pi][sup [minus]]) and [Gamma]([Lambda] [yields] n[pi][sup 0]) are diminished due to Pauli blocking; but a non-mesonic decay mode, nucleon stimulated decay N[Lambda] [yields] Nn, is present and is detected via the energetic decay nucleon(s) (… more
Date: August 1, 1992
Creator: Athanas, M. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Selected problems in experimental intermediate energy physics. [Dept. of Physics, Univ. of Houston]

Description: Objectives of this research program are to investigate forefront problems in experimental intermediate-energy physics, educate students in this field of research, and develop the instrumentation necessary. Generally, this research is designed to search for physical processes that cannot be explained by conventional models of elementary interactions. The program has three major thrusts: strange particle physics, where a strange quark is embedded in the nuclear medium; muon electro-weak decay, wh… more
Date: September 1, 1992
Creator: Mayes, B.W.; Hungerford, E.V. & Pinsky, L.S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

[Particle physics]. [Dept. of Physics, Univ. of California, Los Angeles]

Description: Research in basic particle and nuclear physics by the UCLA Particle Physics Research Group is reported in the following areas: rare decays of [eta] and [mu] to test charge conjugation invariance, QCD, and the Standard Model; tests of charge symmetry and isospin invariance; studies of baryon resonances: [pi]N scattering, inverse pion photoproduction, eta-meson photoproduction, and the production of the eta meson in [pi][sup [minus]]p[r arrow][eta]n; and exploratory investigations in support of n… more
Date: November 1, 1992
Creator: Nefkens, B.M.K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Characterization of porosity via secondary reactor

Description: In this quarterly technical Progress report, we summarize the progress which has been achieved with the development of the small angle scattering capability to be used in the current project. In particular, the following was accomplished during the reporting period. The parameter estimation code, MARQFIT, has been tested and is fully operational. The code has been applied to small angle neutron scattering (SANS) data on coals swollen with deuterated solvents. Application of the FPPS model to th… more
Date: January 1, 1992
Creator: Calo, J.M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Thermal-neutron multiplicity counter measurements

Description: An in-plant thermal-neutron multiplicity counter was designed and built to assay plutonium samples for which the relative ({alpha}, n)neutron yield and the neutron multiplication are not known. Such samples are difficult to assay with conventional neutron coincidence counting techniques. We have characterized this counter with various {sup 252}Cf sources and plutonium samples to study the neutron detection efficiency, electronic dead-time, and neutron die-away properties of the detector and ass… more
Date: January 1, 1992
Creator: Krick, M. S.; Langner, D. G.; Miller, D. W.; Wachter, J. R. & Hildner, S. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Many-body corrections in XAFS

Description: The importance of many-body effects in the theory of XAFS is reviewed. The dominant effects are inelastic losses: Extrinsic losses refer to inelastic losses in the propagation of the photoelectron and are treated using a complex, energy-dependent self-energy. The real part of the self-energy yields an important energy-dependent shift in the phase of the XAFS oscillations, while the imaginary part contributes to the mean-free-path. Intrinsic losses refer to losses associated with the creation of… more
Date: January 1, 1992
Creator: Rehr, J.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Hot Muonic Deuterium and Tritium From Cold Targets

Description: Experiments are described which use a solid hydrogen layer to form muonic hydrogen isotopes in vacuum. The method relies on transfer of the muon from protium to either a deuteron or a triton. The resulting muonic deuterium or muonic tritium will not immediately thermalize because of the very low elastic cross sections, and may be emitted from the surface of the layer. Measurements which detect decay electrons, muonic x-rays, and fusion products have been used to study the processes. A target ha… more
Date: January 1, 1992
Creator: Marshall, G. M.; Beveridge, J. L.; Bailey, J. M.; Beer, G. A.; Knowles, P. E.; Mason, G. R. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Detection of hot muonic hydrogen atoms emitted in vacuum using x-rays

Description: Negative muons are stopped in solid layers of hydrogen and neon. Muonic hydrogen atoms can drift to the neon layer where the muon is immediately transferred. It was found that the time structure of the muonic neon X-rays follows the exponential law where the rate is the same as the disappearance rate of [mu][sup -]p atoms. The pp[mu]-formation rate and the muon transfer rate to deuterium are deduced.
Date: 1992~
Creator: Jacot-Guillarmod, R.; Bailey, J. M.; Beer, G. A.; Knowles, P. E.; Mason, G. R.; Olin, A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Hydraulic testing of modified neutron source rod in type Q septifoil

Description: A Type Q septifoil, two modified partial length control rods, four full length control rods, a source rod containing a dummy neutron source and a guide tube assembly were installed in the Long Term Flow Facility (LTFF) of the HTL. The water level inside the guide tubes over the septifoil was measured by the use of sight tubes connected to pressure taps on the guide tubes or by pressure gages. Pressures were measured at tank bottom and inside the septifoil. The target tank bottom pressure for th… more
Date: October 1, 1992
Creator: Steimke, J. L. & Fowley, M. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

ATW system impact on high-level waste

Description: This report discusses the Accelerator Transmutation of Waste (ATW) concept which aims at destruction of key long-lived radionuclides in high-level nuclear waste (HLW), both fission products and actinides. This focus makes it different from most other transmutation concepts which concentrate primarily on actinide burning. The ATW system uses an accelerator-driven, sub-critical assembly to create an intense thermal neutron environment for radionuclide transmutation. This feature allows rapid tran… more
Date: January 1, 1992
Creator: Arthur, E. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Stress Corrosion Cracking Susceptibility of Irradiated Type 304 Stainless Steels

Description: Slow-strain-rate tensile tests and microstructural analysis by Auger electron spectroscopy were conducted on specimens of high- and commercial-purity (HP and CP) heats of Type 304 stainless steel obtained from neutron absorber tubes and a control blade sheath after irradiation up to 2.5 [times] 10[sup 2l] n[center dot]cm[sup [minus]2] (E > l MeV) in boiling water reactors (BWRs). The susceptibility of the HP absorber tubes to intergranular stress corrosion cracking (IGSCC) was higher than that … more
Date: August 1, 1992
Creator: Chung, H. M.; Ruther, W. E.; Sanecki, J. E. & Kassner, T. F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Stress Corrosion Cracking Susceptibility of Irradiated Type 304 Stainless Steels

Description: Slow-strain-rate tensile tests and microstructural analysis by Auger electron spectroscopy were conducted on specimens of high- and commercial-purity (HP and CP) heats of Type 304 stainless steel obtained from neutron absorber tubes and a control blade sheath after irradiation up to 2.5 {times} 10{sup 2l} n{center_dot}cm{sup {minus}2} (E > l MeV) in boiling water reactors (BWRs). The susceptibility of the HP absorber tubes to intergranular stress corrosion cracking (IGSCC) was higher than that … more
Date: August 1, 1992
Creator: Chung, H. M.; Ruther, W. E.; Sanecki, J. E. & Kassner, T. F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Gadolinium as an element for neutron capture therapy

Description: At BNL, preparations are being made to test in vitro compounds containing Gd and compare their response to the response of GD-DTPA to determine if one or several compounds can be located that enter the cells and enhance the Auger effect. Two similar rotators with positions for cell vials that have been constructed for these tests. The first rotator is made of only paraffin which simulates healthy tissue and provides control curves. The second rotator has 135 ppM of Gd-157 in the paraffin to sim… more
Date: December 31, 1992
Creator: Brugger, R. M.; Liu, H. B.; Laster, B. H.; Gordon, C. R.; Greenberg, D. D. & Warkentien, L. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
Back to Top of Screen