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COUNTING METHODS FOR THE ASSAY OF RADIOACTIVE SAMPLES

Description: A guide is presented for problems involved in counting methods and techniques used in avoiding or correcting . them. Beta, alpha, and gamma counting is treated. Among the items discussed are the geometry factor, absorption, scattering, and background. A bibliography of 164 references is included. (D.J.C.)
Date: May 1, 1961
Creator: Steinberg, E.P.
Partner: UNT Libraries Government Documents Department

Half-Life for Double Beta-Decay

Description: Fireman(1) has reported the results of a rather difficult beta-particle coincidence counting experiment in which the decay of Sn{sup 124} by the simultaneous emission of two negative beta-particles, with a half-life between 0.4 x 10{sup 16} years and 0.9 x 10{sup 16} years, seems to have been observed. This note reports the results obtained from a different and somewhat simpler method of looking for the phenomenon of simultaneous emission of two beta-particles. These results are negative so far and show that this process is considerably less probable in the case chosen by us than in that reported by Fireman. The method consists of looking in uranium samples for 90-year Pu{sup 238} which would come from U{sup 238} by the double beta-particle mechanism since Np{sup 238} is heavier than U{sup 238}, which in turn is substantially heavier than Pu{sup 238}, in the isobaric triplet {sub 92}U{sup 238}-{sub 93}Np{sup 238}-{sub 94}Pu{sup 238}. This chemical method of investigation is particularly applicable to this isobaric triplet because there appears to be no other mechanisms to account for the Pu{sup 238} should it be found. The energetics of the situation are summarized in the following diagram, where the disintegration energies are derived from sources which may be traced through a recent compilation.
Date: October 21, 1949
Creator: Levine, C.A.; Ghiorso, A. & Seaborg, G.T.
Partner: UNT Libraries Government Documents Department

Studies with Colloids Containing Radioisotopes of Yttrium, Zirconium, Columbium, and Lanthanum: 1. The Chemical Principles and Methods Involved in Preparation of Colloids of Yttrium, Zirconium, Columbium, and Lanthanum

Description: For a number of investigations, including fundamental studies of radiation effects on living tissues and therapeutic utilization of radioisotopes, it is valuable to have methods for the selective localization of radioisotopes in certain tissues. Finely dispersed anhydrous chromic phosphate has been found useful by Jones, Wrobel, and Lyons in selectively irradiating the liver and spleen with p{sup 32} beta particles. The present studies, reported in this and the following communication, are concerned with methods for controlled selective localization of colloids (incorporating radioisotopes) in the liver, spleen, or bone marrow, and with an analysis of some of the factors involved in the phenomenon of localization.
Date: April 21, 1948
Creator: Gofman, John W.
Partner: UNT Libraries Government Documents Department

HEAT RELEASE IN NUCLEAR REACTORS

Description: Discussions are included on energy sources and modes of local deposition of heat, fission fragment and BETA decay energy, neutron energy, energy release by BETA decay of activated nuclei, neutron flux distribution, gamma heating calculations, and integration of the gamma heating equation for simple cases. (M.H.R.)
Date: October 1, 1956
Creator: Alexander, L.G.
Partner: UNT Libraries Government Documents Department

SUMMARY REPORT ON THE STUDY OF BETA TREATMENT OF URANIUM

Description: A study was made on the effects of beta treatment variables on the texture, grain size, and distortion in unalloyed dingot and ingot uranium. The effects of delta heat treatment, various cooling regimes, recrystallization, etc., were studied. (D.L.C.)
Date: April 1, 1963
Creator: Russell, R.B. & Wolff, A.K.
Partner: UNT Libraries Government Documents Department

The transmission of differing energy beta particles through various materials

Description: The transmission of beta particles is frequently calculated in the same fashion as that of gamma rays, where the mass attenuation coefficient is defined by the slope of the exponential function. Numerous authors have used this approximation including Evans (1955), Loevinger (1952), and Chabot et. al. (1988). Recent work by McCarthy et. al. (1995) indicated that the exponential function seemed to fit well over a particular region of the transmission curve. Upon further investigation, the author decided to verify McCarthy`s results by the use of different absorber materials and attempt to reproduce the experiments. A theoretical method will be used to estimate the transmission of the beta particles through the three absorbers, aluminum, zirconium, and iron. An alternate Monte Carlo code, the Electron Gamma Shower version 4 code (EGS4) will also be used to verify that the experiment is approximating a pencil beam of beta particles. Although these two methods offer a good cross check for the experimental data, they pose a conflict in regards to the type of beam that is to be generated. The experimental lab setup uses a collimated beam of electrons that will impinge upon the absorber, while the codes are written using a pencil beam. A minor discrepancy is expected to be observed in the experimental results and is currently under investigation by McCarthy. The results of this project supported the theory that the beta mass attenuation coefficient was accurately represented by the slope of an exponential function, but only for that particular region of the transmission curve that has a minimal absorber thickness. By fitting the data beyond 50% of the beta particle range this theory does not hold true. The theory generated by McCarthy (1995) and the EGS4 Monte Carlo code indicated that the transmission curve for a pencil beam was not accurately ...
Date: April 1, 1996
Creator: Quayle, D.R.
Partner: UNT Libraries Government Documents Department

A Calculation of the Beta Energy Absorbed by Tritiated Gases in Spherical Vessels

Description: A calculation of tritium beta energy absorption in spherical bulbs filled with mixtures of tritium and other gases is ' carried out under the empirically substantiated assumption that the energy absorption per spherical shell surrounding a point tritium source is representable by a pure exponential function. Primary and successive backscattering at the wall of the vessel is taken into account by means of a very approximate calculation. The computed energy absorption function for hydrogen gas in a silvered bulb agrees within plus or minus 3% over a wide range of gas pressure with the one available set of spherical ionization chamber data. (auth)
Date: May 22, 1961
Creator: Mueller, M M
Partner: UNT Libraries Government Documents Department

The Eight New Synthetic Elements

Description: In an early continuation of the investigation of the radioactive isotopes of element number 43 (technetium) Segre and Seaborg produced by the deuteron and neutron bombardment of molybdenum the isotope Tc{sup 99}, which they observed to decay by means of an isomeric transition with a half-life of 6.6 hours to a lower isomeric state with a half-life greater than 40 years. The upper isomeric state of this isotope was observed by Segre and C. S. Wu to be produced in the fission of uranium and more recently R. P. Schumann and also D. C. Lincoln and W. H Sullivan working on the Plutonium Project of the Manhattan District have independently observed the beta-particles of half-life about 10 years due to the lower isomeric state. Later work by E. E. Motta and G. E. Boyd sets a more accurate value of 9.4 x 10{sup 5} years for this half-life. Since this isotope is formed in rather large amounts, namely, a fission yield of 6.2%, in the slow neutron induced fission of uranium it is now possible to isolate technetium in weighable amounts and in rather substantial quantities. For example, a uranium pile operating at a power level of 10{sup 5} kw would produce about four grams of technetium, as the isotope T{sup 99}, per day. With such a long half-life the radioactivity associated with convenient amounts (some mg.) would be so small in intensity as to not create a problem provided reasonable care in handling were exercised.
Date: November 1, 1947
Creator: Seaborg, Glenn T.
Partner: UNT Libraries Government Documents Department

Report for General Research December 26, 1950 to April 16, 1951 (Supporting Research Volume)

Description: This volume presents the quarterly results of that portion of the research and development which is directed towards establishing new techniques and instruments and towards improving present methods for determining levels of radioactivity accurately and safely. The locally developed amplifier of high gain and of wide dynamic range has been shown to provide plateaus suitable for the simultaneous counting of alpha and beta particles. Commercially available amplifiers have failed to exhibit suitable plateaus when used under the same conditions. This locally developed amplifier in conjunction with the Nuclear Instruments PC1 chamber has made it possible to estimate beta energies down to 0.02 million electron volt, which is to be compared to a former lower limit of 0.1 million electron volt. A fast neutron survey meter must be simple, lightweight, portable and efficient and must provide discrimination against gamma rays. The first step, which is the design of a suitable detecting device has been successfully completed as good efficiency and good discrimination against gamma rays have been achieved. The necessary electronic circuits must now be engineered to provide the requisite simplicity lightweight and portability.
Date: May 21, 1951
Creator: Haring, M.M.
Partner: UNT Libraries Government Documents Department

Dose algorithm for EXTRAD 4100S extremity dosimeter for use at Sandia National Laboratories.

Description: An updated algorithm for the EXTRAD 4100S extremity dosimeter has been derived. This algorithm optimizes the binning of dosimeter element ratios and uses a quadratic function to determine the response factors for low response ratios. This results in lower systematic bias across all test categories and eliminates the need for the 'red strap' algorithm that was used for high energy beta/gamma emitting radionuclides. The Radiation Protection Dosimetry Program (RPDP) at Sandia National Laboratories uses the Thermo Fisher EXTRAD 4100S extremity dosimeter, shown in Fig 1.1 to determine shallow dose to the extremities of potentially exposed individuals. This dosimeter consists of two LiF TLD elements or 'chipstrates', one of TLD-700 ({sup 7}Li) and one of TLD-100 (natural Li) separated by a tin filter. Following readout and background subtraction, the ratio of the responses of the two elements is determined defining the penetrability of the incident radiation. While this penetrability approximates the incident energy of the radiation, X-rays and beta particles exist in energy distributions that make determination of dose conversion factors less straightforward in their determination.
Date: May 1, 2011
Creator: Potter, Charles Augustus
Partner: UNT Libraries Government Documents Department

Automatic Reader for Air-Monitoring Filter Paper

Description: An automatic reader was developed for scanning 4 x 9in. filter papers from systems that monitor particulate airborne activity. Paper tape shows alpha and betagamma activities, together with counting times and identifying data, for any samples exceeding a predetermined value a special indicator mark is added. (auth)
Date: September 28, 1959
Creator: Thaxter, M. D. & Taussig, Thomas
Partner: UNT Libraries Government Documents Department

ENVIRONMENTAL RADIOACTIVITY AT ARGONNE NATIONAL LABORATORY. Report for the Year 1956

Description: Concentrations of radioactivity in several types of samples obtained from the ANL site and from locations approximately 10, 25, and 100 miles from the Laboratory are given. Since ANL waste water is discharged into Sawmill Creek, which in turn empties into the Des Plaines River, special emphasis was placed on sampling these streams. Most of the results were obtained by coumting the total alpha and beta activities after suitable preparation of the samples. Some of the samples were also analyzed for specific elements and nuclides. The average total activities in water, bottom silt, surface soil, and plants during 1956 are shown. The average activities in these types of samples from 1952 through 1956 are compared. (J.S.R.)
Date: January 1, 1958
Creator: Sedlet, J.
Partner: UNT Libraries Government Documents Department