56 Matching Results

Search Results

Advanced search parameters have been applied.

An Evaluation of Activated Bismuth Isotopes in Environmental Samples From the Former Western Pacific Proving Grounds

Description: {sup 207}Bi (t{sub 1/2}=32.2 y) was generated by activation of weapons material during a few ''clean'' nuclear tests at the U.S. Western Pacific Proving Grounds of Enewetak and Bikini Atolls. The radionuclides first appeared in the Enewetak environment during 1958 and in the environment of Bikini during 1956. Crater sediments from Bikini with high levels of {sup 207}Bi were analyzed by gamma spectrometry in an attempt to determine the relative concentrations of {sup 208}Bi (t{sup 1/2} = 3.68 x 10{sup 5} y). The bismuth isotopes were probably generated during the ''clean'', 9.3 Mt Poplar test held on 7/12/58. The atom ratio of {sup 208}Bi to {sup 207}Bi (R value) ranges from {approx}12 to over 200 in sections of core sediments from the largest nuclear crater at Bikini atoll. The presence of bismuth in the device is suggested to account for R values in excess of 10.
Date: March 21, 2000
Creator: Robison, W.L.; Brunk, J.A. & Jokela, T.A.
Partner: UNT Libraries Government Documents Department

Behavior of Intruder Based States in Light Bi and Tl Isotopes: The Study of <sup>187</sup>Bi Alpha Decay

Description: The excitation energies of the single-particle normal and intruder levels in both `83T1 and 187Bi were measured for the first time via the ct decay of 187Bi produced in the 97Mo(92Mo,pn) 187Bi reaction. The previously unobserved 187Bi ground state (kw) to 183T1 ground state (s1/2) a transition was identified establishing the 187Bi intruder state excitation energy to be 112(21) keV, 70 keV less than that of the same level in 189Bi.
Date: November 13, 1998
Creator: Batchelder, J.C.; Bingham, C.R.; Brown, L.T.; Conticchio, L.F.; Davids, C.N.; DeCoster, C. et al.
Partner: UNT Libraries Government Documents Department

Behavior of intruder based states in light Bi and Tl isotopes: the study of {sup 187 Bi} {alpha} decay

Description: Intruder state excitation energies in odd-mass nuclei just outside a closed proton shell plotted versus neutron number generally exhibit parabola-shaped curves with minima near neutron mid-shells. The Bi isotopes, however, do not seem to follow this trend. Recent experiments performed at Argonne National Laboratory have identified the previously unobserved {sup 187}Bi ground state (h{sub 9/2}) to {sup 183}TI ground state s{sub 1/2} {alpha} transition. Its energy when combined with those of two earlier known transitions, namely {sup 187}Bi (h{sub 9/2}) {yields} {sup 183m}Tl (h{sub 9/2}) and {sup 187m}Bi (s{sub 1/2}) {yields} {sup 183}Tl(s{sub 1/2}), establishes the excitation energies of the {sup 183m}Tl and {sup 187m}Bi to be 620(20) keV and 110(20) keV, respectively. This value for {sup 187m}Bi is 80 keV lower than the excitation energy of the same intruder level in {sup 189}Bi. Implications of this result with respect to intruder-state systematics are discussed.
Date: January 1, 1997
Creator: Batchelder, J.C. & Zganjar, E.F.
Partner: UNT Libraries Government Documents Department

Production and identification of new, neutron-rich nuclei in the {sup 208}Pb region

Description: The recently developed methods allowing the experimental studies on new neutron-rich nuclei beyond doubly-magic {sup 208}Pb are briefly described. An identification of new neutron-rich isotopes {sup 215}Pb and {sup 217}Bi, and new decay properties of {sup 216}Bi studied by means of a pulsed release element selective technique at PS Booster-ISOLDE are reported.
Date: November 1, 1998
Creator: Rykaczewski, K.; Kurpeta, J. & Plochocki, A.
Partner: UNT Libraries Government Documents Department

New heavy proton radioactivities

Description: The new proton radioactivities {sup 165,166,167}Ir, {sup 171}Au, and {sup 185}Bi have been observed, extending our knowledge of proton radioactivity up to and beyond the Z=82 closed shell. For Z=77 and 79, the transitions can be explained using simple shell-model arguments. The case of {sup 185}Bi represents the first example of proton radioactivity from an intruder state.
Date: August 1, 1995
Creator: Davids, C.N.; Woods, P.J. & Batchelder, J.C.
Partner: UNT Libraries Government Documents Department

A rapid, simple method for the determination of the radon content of water

Description: The historical approach to the separation of radon from water is liberation of the radon from the sample by boiling under vacuum in the presence of a strong acid; flushing the liberated radon, with an inert gas, into an ionization chamber or an alpha proportional counters and measuring the collected activity. Such an analysis requires a manipulation time of approximately one hour, a waiting period of two to three hours before measurement to allow transitory equilibrium to be reached, and finally a measurement time, resulting in 4 to 6 hours for one analysis. In addition, specialized equipment including a vacuum train is required. If it is desired to count the alpha particles from radon and its daughters in a proportional counter, absorption trains to remove all oxygen, a poor counting gas, are required. The method presented herein requires only 20--25 minutes for a complete analysis and except for the beta counter utilizes standard laboratory equipment.
Date: June 29, 1950
Creator: Thorburn, R. C. & Healy, J. W.
Partner: UNT Libraries Government Documents Department

Systematics of Alpha-Radioactivity

Description: Correlations of alpha-decay energies in terms of mass number and atomic number have been made for all of the alpha-emitting species now numbering over 100. For each element isotopes show increase in alpha-energy with decrease in mass number except in the region of 126 neutrons where there is an explainable reversal. This reversal has the effect of creating a region of relatively low alpha-energy and long half-life at low mass numbers for such elements as astatine, emanation, francium, and possibly higher elements as had been noted already for bismuth and polonium. Methods and examples of using alpha-decay data to define the energy surface in the heavy element region are discussed. The regularities in alpha-decay are used for predictions of nuclear properties including prediction of the beta-stable nuclides among the heavy elements. The half-life vs. energy correlations show that the even-even nuclides conform well with existing alpha-decay theory, but all nuclear types with odd nucleons show prohibited decay. The reason for this prohibition is not found in spin changes in the alpha-emission but in the assembly of the components of the alpha particle, and this theory is discussed further in terms of observations made on nuclides having two or more alpha-groups. Using most of the even-even nuclei to define 'normal nuclear radius' calculations are now able to show the shrinkage in the regions of lead and of 126 neutrons to amount to about 10%. The much greater change in 'effective radius' for bismuth isotopes can be dissociated into the effects of odd nucleons superimposed on the actual decrease in nuclear radius. The simple expression r = 1.48 A{sup 1/3} {center_dot} 10{sup -13} cm seems to fit the data for the even-even nuclei outside of the region of 126 neutrons better than more complex functions.
Date: September 12, 1949
Creator: Perlman, I.; Ghiorso, A. & Seaborg, G.T.
Partner: UNT Libraries Government Documents Department

Removal of isobaric interferences via pulsed laser resonance ionization mass spectrometry (RIMS) for lead and bismuth mixtures

Description: Pulsed laser single color 2 + 1 multiphoton ionization is used to eliminate isobaric interferences for lead and bismuth mixtures detected via resonance ionization mass spectrometry.
Date: January 1, 1987
Creator: Fearey, B.L.; Anderson, J.E.; Miller, C.M.; Nogar, N.S. & Rowe, M.W.
Partner: UNT Libraries Government Documents Department

Structure of neutron deficient odd-proton nuclei near the shell closure at Z = 82

Description: The experimental data on neutron-deficient, odd-proton isotopes of Au(Z = 79), Tl(Z = 81), and Bi(Z = 83) relevant to core particle coupling schemes and the shell model intruder state phenomenon are presented. The data show that, near the Z = 82 closed proton shell, the unpaired necleon can be used to probe the structure of the core. It is demonstrated that the description of this process in terms of core-particle coupling models enables on to quantify and systematize a large body of experimental data and, consequently, to provide new insights into the relevant nuclear structure. The purity of the particle/hole configurations is discussed. Information on the mechanisms responsible for the disappearance of the Z = 82 shell model gap as the neutron number decreases is obtained from the spectrum of states which result from the coupling of the intruder particle and the even-even core. The observed band structure indicates that the instrusion of the extra shell proton (or proton hole) into the low-energy structure of the neutron-deficient odd-A Au, Tl, and Bi isotopes is not strongly related to the deformation of the core. 6 figures.
Date: January 1, 1979
Creator: Zganjar, E.F.
Partner: UNT Libraries Government Documents Department

Decay of /sup 199m,g/Po: isomeric transitions in /sup 199/Po and /sup 199/Bi

Description: The M4 isomeric transition (E/sub ..gamma../ = 238 keV) of the 13/2/sup +/ state in /sup 199/Po to the 5/2/sup -/ level, with a half life of 4.17 min, has been observed in mass separated sources. An approx. 72 keV transition in coincidence with the isomeric transition suggests the placement of the 5/2/sup -/ level above the 3/2/sup -/, and when combined with ..cap alpha..-decay Q values, this results in a placement of the 13/2/sup +/ isomeric state in /sup 195/Pb at approx. 200 keV. The transition rate for the M4 transition in /sup 199/Po is similar to those for other M4 transitions in this region. Contrastingly, a M4 transition in /sup 199/Bi, which is highly likely to occur on the basis of systematics of 1/2/sup +/ and 9.2/sup -/ states and a sequence of gamma rays among low spin states observed in our data, is highly retarded. Although, this M4 transition is not observable in our data, an upper limit for its strength is established at approx. 1/1000 the intensity of typical M4 transitions in this region. Possible interpretations of this retardation are discussed.
Date: January 1, 1981
Creator: Bingham, C.R.; Stone, R.E.; Riedinger, L.L.; Lide, R.W.; Carter, H.K.; Mlekodaj, R.L. et al.
Partner: UNT Libraries Government Documents Department

Evaluation at the medium energy region for Pb-208 and Bi-209

Description: Medium energy nuclear data in the 1--1000 MeV range is necessary to accelerator applications which include spallation neutron sources for radioactive waste treatment and accelerator shielding design, medical applications which include isotopes production and radiation therapy, and space applications. For the design of fission and fusion reactors, the nuclear data file for neutrons below 20 MeV is available and well evaluated. Evaluated nuclear data for protons and data in the medium energy region, however, have not been prepared completely. Evaluation in the medium energy region was performed using the theoretical calculation code ALICE-P or experimental data. In this paper, the evaluation of neutron and proton induced nuclear data for Pb-208 and Bi-209 has been performed using ALICE-P, empirical calculations and new systematics for the fission cross section. The evaluated data are compiled for possible inclusion in the ENDF/B-VI High Energy File. 204 refs., 51 figs., 9 tabs.
Date: January 1, 1991
Creator: Fukahori, Tokio & Pearlstein, S.
Partner: UNT Libraries Government Documents Department

Low-level gamma-ray spectrometry

Description: Low-level gamma-ray spectrometry generally equates to high-sensitivity gamma-ray spectrometry that can be attained by background reduction, selective signal identification, or some combination of both. Various methods for selectively identifying gamma-ray events and for reducing the background in gamma-ray spectrometers are given. The relative magnitude of each effect on overall sensitivity and the relative cost'' for implementing them are given so that a cost/benefit comparison can be made and a sufficiently sensitive spectrometer system can be designed for any application without going to excessive or unnecessary expense. 10 refs., 8 figs.
Date: October 1, 1990
Creator: Brodzinski, R.L.
Partner: UNT Libraries Government Documents Department

A method to automate the radiological survey process

Description: This document describes the USRAD system, a hardware/software ranging and data transmission system, that provides real-time position data and combines it with other portable instrument measurements. Live display of position data and onsite data reduction, presentation, and formatting for reports and automatic transfer into databases are among the unusual attributes of USRADS. Approximately 25% of any survey-to-survey report process is dedicated to data recording and formatting, which is eliminated by USRADS. Cost savings are realized by the elimination of manual transcription of instrument readout in the field and clerical formatting of data in the office. Increased data reliability is realized by ensuring complete survey coverage of an area in the field, by elimination of mathematical errors in conversion of instrument readout to unit concentration, and by elimination of errors associated with transcribing data from the field into report format. The USRAD system can be adapted to measure other types of pollutants or physical/chemical/geological/biological conditions in which portable instrumentation exists. 2 refs., 2 figs.
Date: January 1, 1987
Creator: Berven, B.A. & Blair, M.S.
Partner: UNT Libraries Government Documents Department

Recoil spectrometer for the detection of single atoms

Description: A much improved version of our gas-filled spectrometer for heavy-ion-induced fusion reactions is described. This instrument (SASSY II) is of the type D-Q-D wherein the dipoles are made with strong vertically-focussing gradients. The problems associated with experiments with cross sections in the picobarn range are discussed. In such experiments, it is necessary to identify single atoms with a high degree of confidence.
Date: April 1, 1987
Creator: Ghiorso, A.
Partner: UNT Libraries Government Documents Department

Aerial radiological survey of the United States Department of Energy's Battelle Nuclear Science Facility, West Jefferson, Ohio, date of survey: May 1977

Description: An aerial radiological survey to measure terrestrial gamma radiation was carried out over the United States Department of Energy's Battelle Nuclear Science Facility located in West Jefferson, Ohio. Gamma ray data were collected over a 5.5 km/sup 2/ area centered on the facility by flying east-west lines spaced 61 m apart. Processed data indicated that on-site radioactivity was primarily due to radionuclides currently being processed due to the hot lab operations. Off-site data showed the radioactivity to be due to naturally occurring background radiation consistent with variations due to geologic base terrain and land use of similar areas.
Date: May 1, 1979
Creator: Feimster, E.L.
Partner: UNT Libraries Government Documents Department

Polarizability of nuclear wave functions in heavy ion reactions. [/sup 208/Pb(/sup 12/C,/sup 11/B)/sup 209/Be, 78 MeV]

Description: Evidence is presented for the polarizability of nuclear wave functions in heavy-ion transfer reactions. The polarization of the wave function of the transferred nucleon is largest for weakly bound nucleons, depends on the bombarding energy (being largest for low-energy (slow) collisions) and produces a shift toward forward angle. Results of an adiabatic estimate employing two-center-shell-model wave functions in a DWBA amplitude are presented. A dynamical theory is sketched which involves a superposition of many transitions through excited bound and continuum states of the weakly bound nucleon. It is shown how the adiabatic amplitude emerges as the lowest approximation. 7 figures.
Date: August 1, 1977
Creator: Charlton, L.A.; Delic, G.; Glendenning, N.K. & Pruess, K.
Partner: UNT Libraries Government Documents Department

Estimating population sizes in a mixture of two radioactive populations

Description: The event times are observed of a mixture of two kinds of radioactive atoms, each producing alpha particles. The probability of observing an event is p, 0 < p < 1, and of missing the observation is 1 - p. A maximum likelihood statistical method is given for estimating the size of the two populations. A second discussion assumes that the populations themselves are samples from parent populations. Bayesian methods are given for estimating parameters of the parent populations. An example is presented of an experiment involving the search for particle-bound polyneutron systems. 2 figures, 3 tables.
Date: April 1, 1978
Creator: Beyer, W.A. & Qualls, C.
Partner: UNT Libraries Government Documents Department

Measurement of the size distributions of radon progeny in indoor air

Description: A major problem in evaluating the health risk posed by airborne radon progeny in indoor atmospheres is the lack of available information on the activity-weighted size distributions that occur in the domestic environment. With an automated, semicontinuous, graded screen array system, we made a series of measurements of activity-weighted size distributions in several houses in the northeastern United States. Measurements were made in an unoccupied house, in which human aerosol-generating activities were simulated. The time evolution of the aerosol size distribution was measured in each situation. Results of these measurements are presented.
Date: January 1, 1990
Creator: Hopke, P.K.; Ramamurthi, M. & Li, C.S.
Partner: UNT Libraries Government Documents Department

Alpha particle emitters in medicine

Description: Radiation-induced cancer of bone, liver and lung has been a prominent harmful side-effect of medical applications of alpha emitters. In recent years, however, the potential use of antibodies labeled with alpha emitting radionuclides against cancer has seemed promising because alpha particles are highly effective in cell killing. High dose rates at high LET, effectiveness under hypoxic conditions, and minimal expectancy of repair are additional advantages of alpha emitters over antibodies labeled with beta emitting radionuclides for cancer therapy. Cyclotron-produced astatine-211 ({sup 211}At) and natural bismuth-212 ({sup 212}Bi) have been proposed and are under extensive study in the United States and Europe. Radium-223 ({sup 223}Ra) also has favorable properties as a potential alpha emitting label, including a short-lived daughter chain with four alpha emissions. The radiation dosimetry of internal alpha emitters is complex due to nonuniformly distributed sources, short particle tracks, and high relative specific ionization. The variations in dose at the cellular level may be extreme. Alpha-particle radiation dosimetry, therefore, must involve analysis of statistical energy deposition probabilities for cellular level targets. It must also account fully for nonuniform distributions of sources in tissues, source-target geometries, and particle-track physics. 18 refs., 4 figs.
Date: September 1, 1989
Creator: Fisher, D.R.
Partner: UNT Libraries Government Documents Department