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Radioisotopes at Work for Agriculture

Description: Introduction: The Office of Isotopes Development of the United States Atomic Energy Commission has requested that Stanford Research Institute prepare a report on the applications of radioisotopes in agriculture.
Date: October 1959
Creator: Homan, A. Gerlof & Tarrice, Richard R.
Partner: UNT Libraries Government Documents Department

Use of fluorescent screens for isotope radiography

Description: Radiographic examination can be performed on items beyond the limitation of conventional isotope radiography without a great loss of resolution. With proper film and screen selection and scatter radiation control, fluorescent screens can be a valuable additional tool for radiography.
Date: January 1, 1979
Creator: Hubbard, S. K.
Partner: UNT Libraries Government Documents Department

Budgets and behaviors of uranium and thorium series isotopes in the Santa Monica Basin off the California Coast

Description: Samples from three time-series sediment traps deployed in the Santa Monica Basin off the California coast were analyzed to study the flux and scavenging of uranium and thorium series isotopes. Variations of uranium and thorium series isotopes fluxes in the water column were obtained by integrating these time-series deployment results. Mass and radionuclide fluxes measured from bottom sediment traps compare favorably with fluxed determined from sediment core data. This agreement suggests that the near-bottom sediment traps are capable of collecting settling particles representative of the surface sediment. The phase distributions of {sup 234}Th in the water column were calculated by an inverse method using sediment trap data, which help to study the variations of {sup 234}Th scavenging in the water column. Scavenging and radioactive decay of {sup 234}Th are the two principal processes for balancing {sup 234}Th budget in the water column. The residence times of dissolved and particulate {sup 234}Th were determined by a {sup 234}Th scavenging model.
Date: December 16, 1991
Creator: Yu, Lei.
Partner: UNT Libraries Government Documents Department

Low capacitance large volume shaped-field germanium detector

Description: A large volume (150 cm/sup 3/) germanium detector with a full- depletion capacitance of only approx.1 pf has been fabricated. The effect of impurity space-charge was utilized to obtain an appropriate electric field distribution in the detector so that carriers are collected on a small area electrode. Detectors based on this principle are capable of very low noise operation and have immediate applications in direct detection dark matter particle experiments. Detector pulse shapes and carrier trapping effects were also examined for possible applications involving higher energy radiations. 9 refs., 10 figs.
Date: October 1, 1988
Creator: Luke, P. N.; Goulding, F. S.; Madden, N. W. & Pehl, R. H.
Partner: UNT Libraries Government Documents Department

Development of resin-bead isotope-dilution mass spectrometric techniques for Tc-99 analysis

Description: An isotope dilution mass spectrometric method was developed for the analysis of Tc-99 after isolating it onto anion exchange resin beads. A single resin bead containing Tc-99 and Tc-97 spike is loaded onto a rhenium V-shaped filament for thermal emission mass spectrometry. The application of this technique requires the use of a mass spectrometer of high abundance sensitivity and pulse counting capability for the necessary ion detection sensitivity. This paper discusses the development of the technique, including the mass spectrometer, choice of filament material, scanning modes, interferences, and present achievable sample sensitivities.
Date: January 1, 1979
Creator: Walker, R.L.
Partner: UNT Libraries Government Documents Department

Thermal Analysis of LANL Ion Exchange Column

Description: This document reports results from an ion exchange column heat transfer analysis requested by Los Alamos National Laboratory (LANL). The object of the analysis is to demonstrate that the decay heat from the Pu-238 will not cause resin bed temperatures to increase to a level where the resin significantly degrades.
Date: June 16, 1999
Creator: Laurinat, J.E.
Partner: UNT Libraries Government Documents Department

Tritium operating safety seminar, Los Alamos, New Mexico, July 30, 1975

Description: A seminar for the exchange of information on tritium operating and safety problems was held at the Los Alamos Scientific Laboratory. The topics discussed are: (1) material use (tubing, lubricants, valves, seals, etc.); (2) hardware selection (valves, fittings, pumps, etc.); (3) biological effects; (4) high pressure; (5) operating procedures (high pressure tritium experiment at LLL); (6) incidents; and (7) emergency planning. (TFD)
Date: March 1, 1976
Partner: UNT Libraries Government Documents Department

Half-Lives of Long-Lived a-Decay, B-Decay, Bb-Decay and Spontaneous Fission Nuclides.

Description: In his review of radionuclides for dating purposes, Roth noted that there were a large number of nuclides, normally considered ''stable'' but which are radioactive with a very long half-life. Roth suggested that I review the data on the half-life values of these long-lived nuclides for a discussion session at the next meeting. These half-life values for long-lived nuclides include those due to various decay modes, {alpha}-decay, {beta}-decay, electron capture decay, {beta}{beta}-decay and spontaneous fission decay. This report is preliminary but will provide a quick overview of the extensive table of data on the recommendations from that review.
Date: June 29, 2001
Creator: Holden, N. E.
Partner: UNT Libraries Government Documents Department

Kinetics of total body retention and clearance of xenon and krypton after inhalation. [/sup 127/Xe, /sup 79/Kr, /sup 85/Kr]

Description: The total body retention of Xe-127 and Kr-79 and their clearance rates following inhalation were measured in vivo. These data are useful for refined Xe-127 dosimetry calculations, to determine the potential radiation hazard of fission product Kr-85, and more generally to study the behavior of anesthetic gases. While data are available on the solubilities and partition coefficients of Xe and Kr in fat, blood, and other individual body constituents, few measurements of their retention and clearance from the entire body have been reported.
Date: January 1, 1976
Creator: Susskind, H.; Atkins, H. L.; Cohn, S. H.; Ellis, K. J. & Richards, P.
Partner: UNT Libraries Government Documents Department

Tritium monitor for fusion reactors

Description: This report describes the design, operation, and performance of a flow-through ion-chamber instrument designed to measure tritium concentrations in air containing /sup 13/N, /sup 16/N, and /sup 41/Ar produced by neutrons generated by D-T fusion devices. The instrument employs a chamber assembly consisting of two coaxial ionization chambers. The inner chamber is the flow-through measuring chamber and the outer chamber is used for current subtraction. A thin wall common to both chambers is opaque to the tritium betas. Currents produced in the two chambers by higher energy radiation are automatically subtracted, leaving only the current due to tritium.
Date: August 1, 1982
Creator: Jalbert, R. A.
Partner: UNT Libraries Government Documents Department

(The determination of sup 222 Rn flux from soils based on sup 210 Pb and sup 226 Ra disequilibrium)

Description: The emanating fraction of radon in soils from the southern part of the United States is about 40% greater than in those from the northern part. The mean {sup 226}Ra activity in the southern soils is also slightly higher and as a consequence the {sup 222}Rn flux derived from the top 50 cm. is greater in the southern samples. We tentatively attribute these observations to the greater degree of weathering associated with the pre-glacial age of the parent material of many of the southern soils. The weathering has concentrated {sup 226}Ra near grain surfaces and results in an increased emanating power for {sup 222}Rn. The estimated correction in {sup 210}Pb analyses described above results in a small decrease in our estimate of the mean loss rate of {sup 222}Rn from the upper 50 cm of soils.
Date: January 1, 1991
Creator: Turekian, K. K.
Partner: UNT Libraries Government Documents Department

Experimental level-structure determination in odd-odd actinide nuclei

Description: The status of experimental determination of level structure in odd-odd actinide nuclei is reviewed. A technique for modeling quasiparticle excitation energies and rotational parameters in odd-odd deformed nuclei is applied to actinide species where new experimental data have been obtained by use of neutron-capture gamma-ray spectroscopy. The input parameters required for the calculation are derived from empirical data on single-particle excitations in neighboring odd-mass nuclei. Calculated configuration-specific values for the Gallagher-Moszkowski splittings are used. Calculated and experimental level structures for /sup 238/Np, /sup 244/Am, and /sup 250/Bk are compared, as well as those for several nuclei in the rare-earth region. The agreement for the actinide species is excellent, with bandhead energies deviating 22 keV and rotational parameters 5%, on the average. Applications of this modeling technique are discussed.
Date: April 4, 1985
Creator: Hoff, R.W.
Partner: UNT Libraries Government Documents Department

State of the science of blood cell labeling

Description: Blood cell labeling can be considered a science in as far as it is based on precise knowledge and can be readily reproduced. This benchmark criterion is applied to all current cell labeling modalities and their relative merits and deficiencies are discussed. Mechanisms are given where they are known as well as labeling yields, label stability, and cell functionality. The focus is on the methodology and its suitability to the clinical setting rather than on clinical applications per se. Clinical results are cited only as proof of efficacy of the various methods. The emphasis is on technetium as the cell label, although comparisons are made between technetium and indium, and all blood cells are covered. 52 refs., 6 figs., 7 tabs.
Date: January 1, 1989
Creator: Srivastava, S. C. & Straub, R. F.
Partner: UNT Libraries Government Documents Department

Radiolabeled red blood cells: status, problems, and prospects

Description: Radionuclidic labels for red cells can be divided into two main categories - cohort or pulse labels, and random labels. The random labels are incorporated into circulating cells of all ages and the labeling process is usually carried out in vitro. The red cell labels in predominant use involve random labeling and employ technetium-99m, chromium-51, indium-111, and gallium-68, roughly in that order. The extent of usefulness depends on the properties of the label such as the half-life, decay mode, and in-vivo stability, etc. Labeled cells can be used for red cell survival measurements when the half-life of the radionuclide is sufficiently long. The major portion of this article deals with random labels.
Date: January 1, 1983
Creator: Srivastava, S.C.
Partner: UNT Libraries Government Documents Department

Detecting isotopic ratio outliers

Description: An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers. 6 refs., 3 figs., 3 tabs.
Date: January 1, 1985
Creator: Bayne, C.K. & Smith, D.H.
Partner: UNT Libraries Government Documents Department

New ideas in dosimetry and damage calculations for fusion materials irradiations

Description: Nuclear data and techniques are being developed to improve our ability to characterize fusion materials irradiations in terms of neutron fluence and spectra as well as damage parameters such as atomic displacements, gas production, and other transmutation. The production of long-lived isotopes are being measured near 14 MeV, including reactions from Al, Fe, and Mo to /sup 26/Al, /sup 53/Mn, and /sup 94/Nb, and measurements for other reactions are in progress. These data can be used for fusion reactor dosimetry, plasma diagnostics, and the estimation of radioactivity in fusion reactor materials. Dosimetry cross sections are being measured for fission reactors using Be(d,n) sources (E/sub d/= 7 to 40 MeV) and monoenergetic neutron sources from 1 to 14 MeV. These data can be used to adjust activation cross sections. Spallation cross sections are being measured for higher-energy accelerator neutron sources. Helium production cross sections are being tested at all fusion irradiation facilities. We have recently discovered a new thermal helium production in copper, similar to the well-known effect in nickel. Recommended procedures have been published for the calculation of helium from both copper and nickel in mixed-spectrum reactors. A new program SPECOMP has recently been developed to calculate displacement damage for compounds. This program uses the SPECTER recoil atom distributions and integrates over secondary displacement functions for each combination of incident ion and matrix material to determine displacement cross sections for alloys, insulators, and breeder materials.
Date: January 1, 1986
Creator: Greenwood, L.R.
Partner: UNT Libraries Government Documents Department

Monitoring tritium in air containing other radioactive gases

Description: A brief survey is presented of methods that have been developed for active tritium monitoring that may be applied to measure tritium concentrations in air containing /sup 13/N, /sup 16/N, and /sup 41/Ar produced by D-T neutrons. Included are instruments that employ current subtraction to achieve discriminations and others that selectively remove atmospheric water vapor from stream of activated air.
Date: September 1, 1982
Creator: Jalbert, Roland A.
Partner: UNT Libraries Government Documents Department

On the measurement of /sup 107/Ag//sup 109/Ag ratios in meteorites

Description: The detection of stable Ag isotopes in meteorites at the ppB level was attempted in an AMS experiment using the Munich MP tandem accelerator in conjunction with a time-of-flight detection system. The sensitivity of detecting Ag at this level was established by observing a counting rate of 17 ions of /sup 107/Ag per sec from a Au sample, which had been spiked with the radioisotope /sup 105/Ag (T/sub 1/2/ = 41 d) at a concentration of 1.0 ppB. A blank Ta sample gave no /sup 105/Ag counts in 13 min, which corresponds to a detection limit of 7.5 x 10/sup -5/ ppB. Although this sensitivity was clearly sufficient to perform /sup 107/Ag and /sup 109/Ag measurements in the desired concentration range, experiments with these isotopes were hampered by a currently irreducable background of stable Ag in the ppM range, possibly originating from the ion source itself. Indications of extraordinarily high Ag concentrations, far above this background, were observed in some of the investigated meteorites, but conclusions on their actual existence must await a better understanding of the origin of the general Ag background. 10 refs., 4 figs., 3 tabs.
Date: January 1, 1986
Creator: Kutschera, W.; Faestermann, T.; Gillitzer, A. & Fortuna, G.
Partner: UNT Libraries Government Documents Department

Very Elongated Nuclei Near a = 194

Description: A {gamma}-ray cascade in {sup 191}Hg of 12 members with average energy spacing 37 keV and Q{sub t} {equals} 18(3)eb was reported by Moore, and coworkers in 1989. This was the first report of very elongated nuclei (superdeformation) in this mass region. Since then, some 25 {gamma}-ray cascades have been observed in 11 (slightly neutron deficient) Hg, Pb and Tl nuclei. The bands have similar dynamic moments-of-inertia. Some nuclei exhibit multiple bands, and the backbending phenomena has been observed. Level spins can be obtained from comparison of transition energies to rotational model formulas. Selected bands (in different nuclei) have equal transition energies (within 0.1%). Alignment in integer multiples of {h bar} has been observed. Properties of these bands will be described. 27 refs., 3 figs.
Date: October 1, 1990
Creator: Becker, J. A.; Henry, E. A.; Yates, S. W.; Wang, T. F.; Kuhnert, A. (Lawrence Livermore National Lab., CA (USA)); Brinkman, M. J. et al.
Partner: UNT Libraries Government Documents Department
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