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Estimating the Cerenkov neutron sensitivity of Suprasil (SiO/sub 2/) and Lucite (C/sub 5/H/sub 8/O/sub 2/)

Description: Fast neutrons hitting a sample of suprasil will produce light. This light is Cerenkov light produced by high energy (> .2 MeV) electrons traversing the transparent medium. Neutrons produce these electrons in a two step process. First, the neutrons inelastically scatter with either the silicon (Si) or the oxygen (O) atoms producing inelastic gamma rays. Some of these gammas, in turn, will also react producing, primarily, Compton electrons with some pair production electrons possible. The majority of these Compton electrons will have enough energy to induce Cerenkov light production. For intermediate energy neutrons (2 to 20 MeV), this process is efficient enough to produce a relatively simple neutron detector with some desirable properties. Estimations of the Cherenkov/neutron sensitivities of suprasil and lucite are presented. (WHK)
Date: April 20, 1982
Creator: Clark, D.
Partner: UNT Libraries Government Documents Department

PROCEEDINGS OF THE CONFERENCE ON RADIOIODINE SPONSORED BY THE ARGONNE CANCER RESEARCH HOSPITAL, UNITED STATES ATOMIC ENERGY COMMISSION, AND THE CLINICS OF THE UNIVERSITY OF CHICAGO, NOVEMBER 5 AND 6, 1956, CHICAGO, ILLINOIS

Description: Applications of the various iodine isotopes in diagnosis and therapy are discussed. Problems of dosimetry and radiation exposure to patients and hospital personnel are considered. Some quantitative aspects of radiation damage in mammals relevant to the clinical use of radioiodine are reviewed. Emphasis is placed on applications of iodine-131 in diagnosis and therapy of hyperthyroidism and hypothyroidism; in the treatmeat of thyroid carcinoma; and in thyroid ablation for cardiac disease. 54 references. (C.H.)
Date: October 31, 1958
Creator: Clark, D.E. ed.
Partner: UNT Libraries Government Documents Department

Conference summary

Description: A brief review is given of the main results presented at the International Conference on Heavy Ion Sources, October 27--30, 1975. The sections are as follows: highlights, general observations, fundamental processes in sources, positive ion sources, negative ion sources, beam formation and emittance measurements, stripping, accelerators and experiments, and future prospects. (auth)
Date: October 1, 1975
Creator: Clark, D.J.
Partner: UNT Libraries Government Documents Department

Interim economic and demographic profile, Benton and Franklin Counties, Washington: Working draft

Description: This report is organized into five sections. Section 2 summarizes the methods used to compile and analyze the data presented in the report. It includes a discussion of the Qualilty Assurance context within which the data were collected, analyzed, and stored; a definition of the variables and time period included in the profile; description of the secondary and primary data collection, compilation, and analysis procedures used in preparing the report; and a summary of the database management system that will be used to store and provide access to the data presented in the the report. Section 3 contains the profile information, organized by topic. A combination of tables, figures, and text are used to describe the economic and demographic conditions in Benton and Franklin counties. Section 4 summarizes outstanding technical issues and data requirements, and Section 5 provides a bibliography of the documents and personal communications from which the data in this report were obtained. 27 refs., 4 figs., 17 tabs.
Date: November 1, 1987
Creator: Clark, D.C.
Partner: UNT Libraries Government Documents Department

Emittance measurements on the LBL ECR source

Description: Measurements of radial emittance and the upper limit of energy spread have been made using a scanning Faraday cup after a waist, on beams of oxygen, argon and krypton. The general features are that the divergence seen at the scanning cup shows a central core and tails on each side. The un-normalized emittance of the beam core decreases with increasing Q/A in a way that is not explained by simple assumptions about the plasma or extraction system. Data from an experimental 1 mm diameter extraction aperture indicates that plasma density is about the same as over the standard aperture, but that the plasma energy spread is reduced to an upper limit of .2 to .4 V, and beam brightness is up by a factor of 10 for medium charge states. 9 refs., 10 figs., 1 tab.
Date: November 1, 1987
Creator: Clark, D.J.
Partner: UNT Libraries Government Documents Department

Ion sources for cyclotrons

Description: This paper describes the principles, performance and future prospects of ion sources used for cyclotrons. Sources discussed include the filament, PIG, ECR, and EBIS sources. 56 references.
Date: September 1, 1981
Creator: Clark, D.J.
Partner: UNT Libraries Government Documents Department

High-charge-state ion sources

Description: Sources of high charge state positive ions have uses in a variety of research fields. For heavy ion particle accelerators higher charge state particles give greater acceleration per gap and greater bending strength in a magnet. Thus higher energies can be obtained from circular accelerators of a given size, and linear accelerators can be designed with higher energy gain per length using higher charge state ions. In atomic physics the many atomic transitions in highly charged ions supplies a wealth of spectroscopy data. High charge state ion beams are also used for charge exchange and crossed beam experiments. High charge state ion sources are reviewed. (WHK)
Date: June 1, 1983
Creator: Clark, D.J.
Partner: UNT Libraries Government Documents Department

Recent progress in ion sources and preaccelerators

Description: Recent progress in ion sources is reviewed. The types of sources discussed include positive and negative proton and deuteron sources developed for conventional preaccelerators and for neutral beam applications. Positive heavy ion sources for conventional linacs and for induction linacs are included. Negative heavy ion sources are used for tandem electrostatic accelerators. Positive and negative polarized ion sources for protons and deuterons inject cyclotrons, tandems, and linacs. Some recent preaccelerator designs are summarized.
Date: September 1, 1979
Creator: Clark, D.J.
Partner: UNT Libraries Government Documents Department

Cyclotrons as mass spectrometers

Description: The principles and design choices for cyclotrons as mass spectrometers are described. They are illustrated by examples of cyclotrons developed by various groups for this purpose. The use of present high energy cyclotrons for mass spectrometry is also described. 28 references, 12 figures.
Date: April 1, 1984
Creator: Clark, D.J.
Partner: UNT Libraries Government Documents Department

Thiophene metabolism by E. coli

Description: The objective of this project is to investigate the mechanism of degradation of sulfur containing heterocyclic molecules such as those found in coal, by mutants of Escherichia coli K-12. We previously isolated multiple mutants of E. coli which were selected for improved oxidation of furan and thiophene derivatives. We have focused on the thdA mutation in our subsequent research as it appears to be of central importance in thiophene oxidation. We hope that analysis of the thd genes of E. coli will lead to improvement of our thiophene metabolizing bacterial strains. 1 tab.
Date: January 1, 1990
Creator: Clark, D.P.
Partner: UNT Libraries Government Documents Department

Thiophene metabolism by E. coli

Description: The objective of this project is to investigate the mechanism of degradation of sulfur-containing heterocyclic molecules by mutant strains of Escherichia coli K-12. We have previously isolated multiple mutants of E. coli which had gained the capacity to oxidize thiophene compounds and their furan analogs. We have focused on the thdA mutation in our subsequent research, as this appears to be in a regulatory gene central to the thiophene/furan oxidation system. The thdF gene appears to be more directly involved in the oxidation reactions, whereas thdC and thdD are apparently required for increased protection against the toxic effects of thiophene and furan compounds. 4 tabs.
Date: January 1, 1991
Creator: Clark, D.P.
Partner: UNT Libraries Government Documents Department

Thiophene metabolism by E. coli

Description: The objective for this project was to continue the genetic analysis of the thiophene oxidation system, in particular: 1. characterization of the biochemical pathway for thiophene oxidation, 2. identification and mapping of any further genes involved in thiophene degradation, 3. analysis of how the thd genes are regulated, and 4. cloning and sequencing of at least some of the thd genes.
Date: January 1, 1991
Creator: Clark, D.P.
Partner: UNT Libraries Government Documents Department

Iron-masonite shield status interim report No. 6

Description: This is number six in a planned series of reports intended to show the status and rates of deterioration of the iron-masonite biological shields of B, Dg DR, F, and H reactors. Since DR, F, and H reactors are in the deactivated state this is the final such report for them. Following the deactivation of D Reactor at the end of June, 1967, B Reactor will be the only one (out of the five with which the shield deterioration study began) to continue operating. Data for this report pertain to the top and left (far) side of the reactors and covers the period from January, 1963, through December, 1966.
Date: June 30, 1967
Creator: Clark, D.E.
Partner: UNT Libraries Government Documents Department

U235: a gamma ray analysis code for uranium isotopic determination

Description: A {sup 235}U analysis code, U235, has been written that can nondestructively determine the percentage of {sup 235}U in a uranium sample from the analysis of the emitted gamma rays. The code is operational and work is now underway to improve the accuracy of the calculation, particularly at the high (>90%) and low (<0.7%) {sup 235}U concentrations. A technique has been found to evaluate low {sup 235}U concentrations that works well on the existing standards. Work is now under way to evaluate this technique for other detectors and other types of samples. Work is also proceeding on: (1) ways to better determine gamma backgrounds, (2) techniques to determine the equivalent thickness of the sample to correct for gamma attenuation, (3) evaluation of the existing data base of branching ratios of {sup 235}U, {sup 238}U and their daughters gamma rays to allow better results and (4) evaluation of the existing data base on the emission ratios for uranium, thorium, and protactinium x-rays.
Date: December 1, 1997
Creator: Clark, D.
Partner: UNT Libraries Government Documents Department

Synchrotrons in cyclotron territory

Description: Synchrotrons and cyclotrons have an overlap in their particle and energy ranges. In proton radiotherapy, synchrotrons are proposed at 250 MeV, an energy usually served by cyclotrons. Heavy ion therapy has been synchrotron territory, but cyclotrons may be competitive. In nuclear science, heavy ion synchrotrons can be used in the cyclotron energy range of 10-200 MeV/u. Storage rings are planned to increase the flexibility of several cyclotrons. For atomic physics research, several storage rings are under construction for the energy range of 10 MeV/u and below.
Date: October 1, 1986
Creator: Clark, D.J. & Gough, R.A.
Partner: UNT Libraries Government Documents Department

Operation of the LBL ECR source injection system

Description: The injection system for the LBL 88-Inch Cyclotron ECR source has been in operation since October 1984. It consists of 7 meters of horizontal beam line following the ECR source analyzing magnet, and 4 meters of vertical beam line down the axis of the cyclotron. Beams throughout the cyclotron energy range of 1 to 32 MeV/u, and particles from protons to xenon have been injected and accelerated in the cyclotron on 1st, 3rd, 5th and 7th harmonic modes. A non-scaling mode of operation is used in which a source voltage of about 10 kV is used for all beams. The overall transmission from source analyzing magnet to cyclotron external beam is typically 10%. The reliability and stability of the system has been excellent.
Date: October 1, 1986
Creator: Clark, D.J. & Lyneis, C.M.
Partner: UNT Libraries Government Documents Department

Definition of the waste package environment for a repository located in salt

Description: The expected environmental conditions for emplaced waste packages in a salt repository are simulated in the materials testing program to evaluate performance. Synthetic brines, based on the analyses of actual brines (both intrusion and inclusion), are used for corrosion and leach testing. Elevated temperatures (to 150/sup 0/C) and radiation fields of up to 10/sup 3/ rad/h are employed as conservative conditions to bracket expected performance and provide data for worst case scenarios. Obtaining a precise definition of the waste package environment in a salt repository and its change with time is closely tied to detailed site characterization of the candidate salt repository horizon. It is expected that field testing can augment some of the materials testing currently under way and can provide increased confidence in the predicted site-specific near-field conditions. 17 references, 5 figures, 1 table.
Date: January 1, 1983
Creator: Clark, D. E. & Bradley, D. J.
Partner: UNT Libraries Government Documents Department

The production of beams from solid materials at the LBL ECR source

Description: Two ovens are described for the feed of vapor from solid materials in the LBL ECR source. A low temperature oven, operating up to 700 /degree/ C, has been used for Li, Mg, P, K, Ca, Ti and Bi. A high temperature oven operating up to 2000/degree/C, has been used for Sc, Fe, Ni, Cu, Ag, La and Tb. At the 1 e..mu..A level the charge states from the oven beams are very close to those from gases. 4 refs., 5 figs., 2 tabs.
Date: September 1, 1988
Creator: Clark, D. J. & Lyneis, C. M.
Partner: UNT Libraries Government Documents Department

First operation of the LBL ERC ion source with the 88-inch cyclotron

Description: The LBL ECR ion source and new injection system are now in regular operation with the 88-Inch Cyclotron supplying stable, reliable heavy ion beams for both nuclear physics and applied research. The ions accelerated to date cover the mass range from nitrogen to xenon, and the energy range of 3 to 27 MeV/nucleon. Overall transmission of up to 14% from source to external cyclotron beam has been obtained. A beam from solid material, magnesium, has been used successfully for an experimental run. The emittance has been measured, at 10 kV accelerating voltage, for a variety of ions and has been found to vary from 100..pi.. mm mrad for the low charge states to 20..pi.. mm mrad for high charge states, for about 50% of the beam. 10 refs., 1 fig., 2 tabs.
Date: May 1, 1985
Creator: Lyneis, C.M. & Clark, D.J.
Partner: UNT Libraries Government Documents Department