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in subjects: "Neutron Beams"

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Polarized neutrons and their applications

The role of polarized neutrons in the study of magnetic and nonmagnetic materials is discussed. magnetic structure, spin density, nuclear magnetism and spin dynamics are listed as magnetic properties which may be accessed by polarized neutrons. Low dimensional magnets, disordered magnetic systems, surface magnetism are discussed as well as topography and depolarization. Polarization techniques are discussed for both study state and pulsed modes. 4 refs. (WRF)

Date: January 1, 1985

Creator: Moon, R.; Endoh, Y.; Felcher, G.; Majkrzak, C.; Mezei, F.; Pynn, R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Intercomparison study of elemental abundances in raw and spent oil shales

Two samples each of raw oil shale and spent oil shale were prepared as reference samples and analyzed by four laboratories using neutron activation analysis, x-ray fluorescence spectrometry, atomic absorption spectroscopy, and other techniques. Excellent agreement was obtained between techniques and laboratories except for the thin-film XRF technique. The %RMS deviations were less than or equal to 10% for 85% of the values. In general, the INAA analysis procedures yielded the most accurate and … more

Date: March 1, 1979

Creator: Fox, J.P.; Evans, J.C.; Wildeman, T.R. & Fruchter, J.S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Measured neutron beam line shielding effectiveness of several iron/polyethylene configurations

Neutron and gamma-ray leakage measurements were taken at various stages of shield construction of neutron flight path 5 (the Lash-up flight path) at LANSCE, to compare the relative effectiveness of several configurations. Dose equivalent rates were determined for three categories: ''low-energy neutrons'', below 20 MeV; ''high- energy neutrons'', above 20 MeV; and gamma rays, as measured by hand-held survey instruments. The low energy neutrons were measured by activation of an indium foil in a p… more

Date: January 1, 1988

Creator: Legate, G.L.; Howe, M.L. & Mundis, R.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Measurement of lithium in target slugs by neutron transmission

An instrument was developed to measure nondestructively the lithium content of target slugs for the SRP reactors. The slugs consist of cylindrical pieces of Li-Al alloy, approximately 0.8 inches in diameter and 12 inches in length, clad with aluminum. The instrument utilizes neutron transmission to determine the Li content in the range 3% to 7% Li.

Date: February 1, 1955

Creator: Dexter, A.H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Oxygen enhancement ratio as a function of neutron energy with mammalian cells in culture

Chinese hamster cells (V79) in culture under oxic and hypoxic conditions were irradiated with several neutron beams spanning a wide energy range. Eight essentially monoenergetic neutron beams, ranging from 0.22 to 13.6 MeV and a 0.11 MeV neutron spectrum, were produced at the Radiological Research Accelerator Facility (RARAF) at Brookhaven National Laboratory. Additional experiments were performed at the Naval Research Laboratory, Washington, D.C., where neutrons are produced for radiotherapy b… more

Date: unknown

Creator: Rini, F. J.; Hall, E. J. & Marino, S. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Status report on conversion of the Georgia Tech Research Reactor to low enrichment fuel

The 5 MW Georgia Tech Research Reactor (GTRR) is a heterogeneous, heavy water moderated and cooled reactor, fueled with highly-enriched uranium aluminum alloy fuel plates. The GTRR is required to convert to low enrichment (LEU) fuel in accordance with USNRC policy. The US Department of Energy is funding a program to compare reactor performance with high and low enrichment fuels. The goals of the program are: (1) to amend the SAR and the Technical Specifications of the GTRR so that LEU U{sub 3}S… more

Date: January 1, 1991

Creator: Karam, R. A.; Matos, J. E.; Mo, S. C. & Woodruff, W. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Nuclear-pumped lasers for large-scale applications

Efficient initiation of large-volume chemical lasers may be achieved by neutron induced reactions which produce charged particles in the final state. When a burst mode nuclear reactor is used as the neutron source, both a sufficiently intense neutron flux and a sufficient short initiation pulse may be possible. Proof-of-principle experiments are planned to demonstrate lasing in a direct nuclear-pumped large-volume system: to study the effects of various neutron absorbing materials on laser perf… more

Date: January 1, 1988

Creator: Anderson, R. E.; Leonard, E. M.; Shea, R. E. & Berggren, R. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Magnetic scattering and polarized neutrons

The last few years have witnessed considerable progress in the use of polarized neutron beam techniques for the study of condensed matter physics. Among the methods actively pursued at present are neutron spin echo as pioneered by Mezei for ultra high resolution and the energy integrated magnetic scattering measurement technique developed by Brown and Ziebeck. We have concentrated on a medium resolution range utilizing 5 to 100 MeV polarized neutrons. In this review we discuss recent work at Br… more

Date: January 1, 1985

Creator: Shirane, G. & Majkrzak, C.F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Measurement of Ultracold Neutrons Produced by Using Doppler-Shifted Bragg Reflection at a Pulsed-Neutron Source

Ultracold neutrons (UCN) have been produced at the Argonne pulsed-neutron source by the Doppler shift of 400-m/s neutrons Bragg reflected from a moving crystal. The peak density of UCN produced at the crystal exceeds 0.1 n/cm/sup 3/.

Date: January 1, 1979

Creator: Brun, T. O.; Carpenter, J. M.; Krohn, V. E.; Ringo, G. R.; Cronin, J. W.; Dombeck, T. W. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Use of a semi-opaque beamstop for monitoring sample transmissions at GLAD (Glass, Liquid, and Amorphous Materials Diffractometer)

Accurate corrections for many types of measurements made on time-of-flight neutron diffractometers require data on the macroscopic transmission cross-section of the sample used, and this data must span the entire wavelength range covered by the instrument. This report describes a transmission monitor consisting of a semi-opaque beamstop in from of a portion of the array of position-sensitive detectors used for diffraction measurements on the GLAD prototype. The semi-opaque beamstop was made of … more

Date: January 1, 1990

Creator: Montague, D.G.; Carpenter, J.M.; Crawford, R.K.; Dejus, R.; Price, D.L. & Susman, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Description and performance characteristics for the neutron Coincidence Collar for the verification of reactor fuel assemblies

An active neutron interrogation method has been developed for the measurement of /sup 235/U content in fresh fuel assemblies. The neutron Coincidence Collar uses neutron interrogation with an AmLi neutron source and coincidence counting the induced fission reaction neutrons from the /sup 235/U. This manual describes the system components, operation, and performance characteristics. Applications of the Coincidence Collar to PWR and BWR types of reactor fuel assemblies are described.

Date: August 1, 1981

Creator: Menlove, H. O.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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LANSCE (Manuel Lujan, Jr. Neutron Scattering Center) target system performance

We measured neutron beam fluxes at LANSCE using gold foil activation techniques. We did an extensive computer simulation of the as-built LANSCE Target/Moderator/Reflector/Shield geometry. We used this mockup in a Monte Carlo calculation to predict LANSCE neutronic performance for comparison with measured results. For neutron beam fluxes at 1 eV, the ratio of measured data to calculated varies from /approx/0.6-0.9. The computed 1 eV neutron leakage at the moderator surface is 3.9 /times/ 10/sup … more

Date: January 1, 1989

Creator: Russell, G. J.; Gilmore, J. S.; Robinson, H.; Legate, G. L.; Bridge, A.; Sanchez, R. J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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New look at displacement factor and point of measurement corrections in ionization chamber dosimetry

A new technique is presented for determination of the effective point of measurement when cavity ionization chambers are used to measure the absorbed dose due to ionizing radiation in a dense medium. An algorithm is derived relating the effective point of measurement to the displacement correction factor. This algorithm relates variations of the displacement factor to the radiation field gradient. The technique is applied to derive the magnitudes of the corrections for several chambers in a p(6… more

Date: January 1, 1983

Creator: Awschalom, M.; Rosenberg, I. & Ten Haken, R.K.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Fail-safe ion chamber errant beam detector tailored for personnel protection

This fail-safe ion chamber system is designed to be part of the personnel safety system (PSS) for the Los Alamos Neutron Scattering Center (LANSCE) at the Los Alamos National Laboratory. Its job is to protect the occupants of the experimental areas from large radiation doses caused by errant beam conditions during beam transport from the Proton Storage Ring (PSR) to the LANSCE neutron spallation target. The worst case beam spill scenario is calculated to result in a personnel exposure of about … more

Date: January 1, 1989

Creator: Plum, M. A.; Browman, A. A.; Brown, D.; Lee, D. M. & McCabe, C. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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High-energy-neutron damage in Nb/sub 3/Sn: changes in critical properties, and damage-energy analysis

Filamentary wires of Nb/sub 3/Sn have been irradiated with fission-reactor, 14.8-MeV, and d-Be neutrons and the changes in critical properties measured. The changes observed scale reasonably well with the calculated damage energies for the irradiations. A critical dose for operation of these conductors in fusion-magnet applications is determined to be 0.19 eV/atom damage energy or 0.0019 dpa.

Date: January 1, 1981

Creator: Snead, C. L., Jr.; Parkin, D. M. & Guinan, M. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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New instruments and techniques in neutron capture studies

Three general topics are addressed. The first deals with crystal diffraction gamma-ray spectrometers, in particular, with the highly productive GAMS spectrometers at the ILL reactor in Grenoble. They are described in detail because of their great potential for producing capture gamma-ray data of the highest quality. Future possibilities for other developments in the area of crystal diffraction spectroscopy of capture gamma rays are also mentioned. Improved neutron beam facilities for capture ga… more

Date: January 1, 1978

Creator: Kane, W.R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Studies of neutron irradiation effects at IPNS-REF

Neutron irradiation effects studies at the Radiation Effects Facility (REF) at the Intense Pulsed Neutron Source (IPNS) located at Argonne National Laboratory (ANL) are reviewed. A brief history of the development of this user facility is followed by an overview of the scientific program. Experiments unique to a spallation neutron source are covered in more detail. Future direction of research at this facility is suggested.

Date: September 1, 1983

Creator: Kirk, M.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Characteristics of A-150 plastic-equivalent gas in A-150 plastic ionization chambers for p(66)Be(49) neutrons

The evaluation of a gas mixture having an atomic composition similar to that of A-150 TE-plastic has been extended to a high energy neutron therapy beam. A-150 gas, air and methane-based TE gas were each flowed through A-150 plastic-walled ion chambers of different sizes and irradiated with p(66)Be(49) neutrons. A tentative value for anti W(A-150) of 27.3 +- 0.5 J C/sup -1/ was derived for this beam. The anti W value of the A-150 gas mixture is compared to those of methane-based TE gas and of a… more

Date: July 8, 1982

Creator: Awschalom, M.; Rosenberg, I.; Ten Haken, R. K.; Pearson, D. W.; Attix, F. H. & DeLuca, P. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Mechanisms affecting swelling in alloys with precipitates

In alloys under irradiation many mechanisms exist that couple phase instability to cavity swelling. These are compounded with the more familiar mechanisms associated with point defect behavior and the evolution of microstructure. The mechanisms may be classified according to three modes of operation. Some affect cavity swelling directly by cavity-precipitate particle association, others operate indirectly by precipitate-induced changes in sinks other than cavities and finally there are mechanis… more

Date: January 1, 1980

Creator: Mansur, L.K.; Haynes, M.R. & Lee, E.H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Neutron resonance averaging with filtered beams

Neutron resonance averaging using filtered beams from a reactor source has proven to be an effective nuclear structure tool within certain limitations. These limitations are imposed by the nature of the averaging process, which produces fluctuations in radiative intensities. The fluctuations have been studied quantitatively. Resonance averaging also gives us information about initial or capture state parameters, in particular the photon strength function. Suitable modifications of the filtered … more

Date: January 1, 1985

Creator: Chrien, R. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Inelastic Neutron Scattering From Amorphous Hydride of Zr/sub 2/Pd

Time-of-flight inelastic neutron scattering data was obtained on hydrided Zr/sub 2/Pd metallic glass using the Crystal Analyzer Spectrometer at the Los Alamos pulsed spallation neutron source. Energy transfers from about 40 MeV to several hundred MeV were obtained with sufficiently good statistics and signal to noise ratio to show the second harmonic as well as the fundamental hydrogen optic mode.

Date: January 1, 1983

Creator: Williams, A.; Eckert, J.; Yeh, X. L.; Atzmon, M. & Samwer, K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Polarizing multilayer spectrometer for neutrons

Polarizing neutron monochromators were prepared by sputtering thin-film multilayers with d-spacings from 40 to 85A on large float-glass substrates. Peak reflectivities as great as 90% and polarizing efficiencies of 98% were measured. Increased angular acceptances were obtained by fabricating multilayers with multiple d- spacings. A planned polarized beam spectrometer which incorporates the multilayers and which has a variable energy resolution independent of angular beam divergence is described. more

Date: January 1, 1981

Creator: Majkrzak, C.F.; Passell, L. & Saxena, A.M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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High-let radiation carcinogenesis

Recent results for neutron radiation-induced tumors are presented to illustrate the complexities of the dose-response curves for high-LET radiation. It is suggested that in order to derive an appropriate model for dose-response curves for the induction of tumors by high-LET radiation it is necessary to take into account dose distribution, cell killing and the susceptibility of the tissue under study. Preliminary results for the induction of Harderian gland tumors in mice exposed to various heav… more

Date: January 1, 1982

Creator: Fry, R.J.M.; Powers-Risius, P.; Alpen, E.L.; Ainsworth, E.J. & Ullrich, R.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Recent activities of the International Group on Research Reactors (IGORR) and of the Advanced Neutron Source (ANS). [Advanced Neutron Source Project]

The International Group on Research Reactors (IGORR) was formed in 1990 to facilitate the sharing of knowledge and experience among those institutions and individuals who are actively working to design, build, and promote new research or to make significant upgrades to existing facilities. The Advanced Neutron Source Project expects to complete conceptual design in mid-1992. In the present design concept, the neutron source is a heavy-water-cooled, moderated, and reflected reactor of about 350 … more

Date: January 1, 1991

Creator: West, C.D.

Item Type: Article

Partner: UNT Libraries Government Documents Department