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Description: To enhance the measurement capability of EICs to alpha spectrometry, measurements at FIU-HCET were performed on different energy alpha sources, and response factors of ST electrets in 960-mL chamber were determined. Earlier, EIC was considered as only a charge-integrating device without spectrometric capability. This is a potentially significant development accomplished by FIU-HCET. It could appreciably lower the current cost of spectral characterization. FIU-HCET has been invited to participate in the Operating Engineers' National Hazmat program's assessment of the Mini Mitter, commercially known as the VitalSense{trademark} Telemetric Monitoring System. This evaluation is scheduled for early July 1999. Additional health and safety technology evaluations, in which FIU-HCET will also participate, are also scheduled for later in the summer. The Technology Information System (TIS), MISD, and DASD are now complete and accessible through the Internet website http://www.DandD.org/tis.
Date: June 30, 1999
Creator: Ebadian, M.A.
Partner: UNT Libraries Government Documents Department


Description: The authors describe experiments with liquid-xenon-filled wire chambers operating in the proportional mode and the difficulty of achieving useful gain when the anode wires have a spacing < 1 mm. As a result, they have largely turned our attention to chambers with closely spaced wires operated in the ionization mode. They have previously demonstrated a spatial resolution of 15 {micro} rms in this mode, using a 5-wire chamber and a collimated alpha source. They describe the construction of two small high-resolution test chambers to be filled with liquid argon, krypton, or xenon. The chambers consist of two flat cathodes 1 to 2.5 mm apart with a wire plane between them. The wire plane is an array of 24 wires, 5 {micro} in diameter, spaced on 20-{micro} centers, and a charge amplifier is attached to each wire. The space resolution (expected rms < 20 {micro}), time resolution (expected rms < 50 ns), and efficiency will be measured in an accelerator beam. Chambers of this type with only a few hundred wires have sufficient area to cover nearly every beam at NAL.
Date: April 1, 1973
Creator: Derenzo, S.E.; Schwemin, A.; Smits, R.G.; Zaklad, H. & Alvarez, L.W.
Partner: UNT Libraries Government Documents Department

Measurement of the Internal Magnetic Field of Plasmas using an Alpha Particle Source

Description: The internal magnetic fields of plasmas can be measured under certain conditions from the integrated v x B deflection of MeV alpha particles emitted by a small radioactive source. This alpha source and large-area alpha particle detector would be located inside the vacuum vessel but outside the plasma. Alphas with a typical energy of 5.5 MeV (241Am) can reach the center of almost all laboratory plasmas and magnetic fusion devices, so this method can potentially determine the q(r) profile of tokamaks or STs. Orbit calculations, background evaluations, and conceptual designs for such a vxB (or ''AVB'') detector are described.
Date: May 13, 2004
Creator: Zweben, S.J.; Darrow, D.S.; Ross, P.W.; Lowrance, J.L. & Renda, G.
Partner: UNT Libraries Government Documents Department


Description: A series of fires and explosions in U. S. Atomic Energy Commission facilities handling alpha -active materiais during the last five years resulted in reconsideration of safety problems associated with glove boxes and other equipment used to contain these materials. The literature on construction and operation of glove boxes for work with toxic inorganic materials not requiring biological shielding is reviewed as a contribution to this re-examination, with special emphasis on methods and equipment for working safely with plutonium and other alpha -active materials. An effort was made to point out the direction of current trends in this field. Detailed discussions of glove box designs and methods of experimentation in these enclosures are not included in this report but sufficient information is furnished for finding needed details in the referenced material. Methods for the detection and measurement of alpha -active materials and of impurities in controlled atmospheres are discussed. In addition, the literature on controlled atmosphere enclosures, glove boxes for non- toxic inorganic materials, and the technique of experimenting with such enclosures is reviewed. Some previously unpublished developments are reported. (auth)
Date: June 14, 1961
Creator: Barton, C.J.
Partner: UNT Libraries Government Documents Department


Description: A new rapid method for the determination of actinides in soil and sediment samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for samples up to 2 grams in emergency response situations. The actinides in soil method utilizes a rapid sodium hydroxide fusion method, a lanthanum fluoride soil matrix removal step, and a streamlined column separation process with stacked TEVA, TRU and DGA Resin cartridges. Lanthanum was separated rapidly and effectively from Am and Cm on DGA Resin. Vacuum box technology and rapid flow rates are used to reduce analytical time. Alpha sources are prepared using cerium fluoride microprecipitation for counting by alpha spectrometry. The method showed high chemical recoveries and effective removal of interferences. This new procedure was applied to emergency soil samples received in the NRIP Emergency Response exercise administered by the National Institute for Standards and Technology (NIST) in April, 2009. The actinides in soil results were reported within 4-5 hours with excellent quality.
Date: November 9, 2009
Creator: Maxwell, S.; Culligan, B. & Noyes, G.
Partner: UNT Libraries Government Documents Department


Description: A Po/sup 210/ source was used to furnish a reliab1e ground for both electron and positron sources. This was done to prevent the electron and positron sources from charging during BETA spectral studies in magnetic lens spectrometers. An approximately 20- mu c Po/sup 210/ source was placed 1.2 in. behind a 4- mu c Na/sup 2 / 2>s positron emitter backed by 20- mu g/cm/sup 2/ Formvar in the spectrometer; this arrangement resulted in a charging rate decrease of approximately 80%. When the source was placed 0.5 in. away, no charging was detectable over a period of more than one week. The discharge is attributed mainly to the loss of electrons from the source and backing caused by ionization of alpha particles since few alpha particles are stopped near the source. (B.O.G.)
Date: December 1, 1960
Creator: Nichols, R.T. & Jensen, E.N.
Partner: UNT Libraries Government Documents Department

Alpha irradiation modeling

Description: With the end of the Cold War and the associated limitations imposed on the nuclear weapons stockpile by strategic arms treaties, much has changed in the stockpile stewardship program. Weapons that were originally designed for stockpile lives on the order of 15 to 20 years are now being evaluated for much longer periods: in some cases as much as 60 years. As such, issues that were once considered to be of no consequence are being reexamined. Among these is the extent of the radiation dose received by secondary organics over time that results from the intrinsic alpha source of the weapon components. This report describes the results of work performed to estimate the alpha radiation deposition in the organic components of an LLNL system at specific points in its stockpile life. Included are discussions of the development of the intrinsic time- and energy-dependent alpha source term per unit mass, estimation of the effective source and absorber material thicknesses, development of a simplified model for the total intrinsic alpha source term and energy deposition in the absorber, and the alpha radiation deposition in the organic components of a selected LLNL weapon.
Date: March 26, 1999
Creator: Keeton, S C & Mount, M E
Partner: UNT Libraries Government Documents Department


Description: A study was made of the preparation of alpha, gamma, and neutron sources using the long-lived radioisotope of americium, Am/sup 241/. Americium-241 is an artificiallyproduced radioelement which has a half-life of 462 plus or minus 10 years and decays to Np/sup 237/ by alpha emission followed by low-energy gamma emission. The high specific activity of americium-241 (7.0 x 10/sup 9/ d/m/mg) combined with its reasonably long half-life makes it ideally sulted for the preparation of radioactive sources. The chemical and physical properties of Am/ sup 241/ and the physical manipulations involved in fabricating alpha, gamma, and neutron sources are generally described in this report. Uses for each type of source are discussed and data are presented to indicate the respective properties and usefulness of each source type. (auth)
Date: September 1, 1962
Creator: Strain, J.E. & Leddicotte, G.W.
Partner: UNT Libraries Government Documents Department


Description: A transistorized instrument prototype was designed and constructed to replace a vacuum-tube instrument in an alpha gauge, which measures the thickness density of gases. The instrument amplifies, shapes, discriminates, and counts alpha pulses from a Au-Si surface-barrier detector exposed to an alpha source in a gas-filled chamber. The circuit consists of a charge-sensitive preamplifier, a main amplifier with pulse clipping, a Schmitt trigger, a diode pump, and a count rate meter. Preliminary tests gave results comparable to the vacuum-tube instrument. Accuracy of counting was within 10% for 0.5- to 10-Mev alpha particles emitted at a maximum rate of 10/sup 6 per sec. The instrument was stable at 25 to 55 deg C, is small and portable, and costs less than 0. An infinitely thick, alpha source that will give a high count rate is being constructed for final tests. (auth)
Date: August 23, 1962
Creator: Kopp, M.C.
Partner: UNT Libraries Government Documents Department

Radioactive check sources for alpha and beta sensitive radiological instrumentation

Description: Since 1991, the Westinghouse Hanford Company has examined the construction and use of alpha and beta radioactive check sources for calibrating instruments and for performing response checks of instruments used for operational and environmental radiation detection. The purpose of using a radioactive check source is to characterize the response of a radiation monitoring instrument in the presence of radioactivity. To accurately calibrate the instrument and check its response, the check source used must emulate as closely as possible the actual physical and isotopic conditions being monitored. The isotope employed and the physical methods used to fabricate the check source (among other factors) determine instrument response. Although information from applicable national and international standards, journal articles, books, and government documents was considered, empirical data collected is most valuable when considering the type of source to use for a particular application. This paper presents source construction methods, use considerations, and standard recommendations. The results of a Hanford Site evaluation of several types of alpha and beta sources are also given.
Date: June 1, 1994
Creator: Barnett, J. M. & Kane, J. E. II
Partner: UNT Libraries Government Documents Department

Report for General Research January 8, to April 30, 1951 (Alpha - Neutron Volume)

Description: An experimental, gamma-sensitive, coaxial radioelectric cell has been tested by the Control Section. It was found to be as precise as the rotating sample gamma counter but much faster and simpler to operate. A gamma-sensitive, radioelectric cell of improved design has been constructed for the 'Y' Section. A neutron sensitive radioelectric cell has been tested over a range of pressures with various filling gases and with several combinations of hydrogenous electrode backings. Neutron to gamma discrimination ratios as high as 2,000 to 1 were obtained, A multiple electrode, alpha radiation, radioelectric cell using coated plastic electrodes gave increased current output, but the electrode life was quite short. Preliminary life tests indicated that aluminum electroscope foil would give excellent electrode life and techniques were worked out for making good electrodes of both aluminum and of gold electroscope foil. The vacuum-pressure gas system has been redesigned and completely rebuilt (p. 5) The fast-neutron scintillation counter is much smaller and lighter than a B-wall proportional counter and a large moderator. The former is more efficient for polonium-beryllium neutron sources but is less efficient for radium-beryllium neutron sources or for polonium sources producing lower energy neutrons The fast neutron scintillation counter would thus be very useful if the neutron to gamma discrimination ratio could be markedly improved. Preliminary experiments indicate that this ratio can be improved by carefully tailoring the frequency response characteristics of the amplifier used. Phosphors are also being investigated from the standpoint of improving this ratio. Preliminary attempts to detect neutrons by measuring the neutron-capture gamma of cadmium were unsuccessful. However, the conversion gamma from alpha-beryllium neutron sources can be detected with high efficiency; and this might be used to determine the neutron flux from such sources even in the presence of high backgrounds of lower energy gammas (p. 8). Maximum ...
Date: January 4, 1951
Creator: Haring, M.M.
Partner: UNT Libraries Government Documents Department