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Theory of Alpha Decay

Description: The relationship between nuclear reactions and nuclear decay derived by F. T. Smith is presented and illustrated by a simple example. (auth)
Date: August 1, 1962
Creator: Tobocman, W.
Partner: UNT Libraries Government Documents Department

Theoretical Alpha Star Populations in Loaded Nuclear Emulsions

Description: Abstract: "Calculations have been made of alpha star populations in loaded nuclear emulsions. Equations are presented for calculation of star types for each significant emitter in the three naturally radioactive series. The application of five-branched star populations as a method of quantitative analysis for microgram amounts of thorium is proposed."
Date: November 1953
Creator: Senftle, F. E.; Farley, T. A. & Stieff, L. R.
Partner: UNT Libraries Government Documents Department

Lightest Isotope of Bh Produced Via the 209Bi(52Cr,n)260BhReaction

Description: The lightest isotope of Bh known was produced in the new {sup 209}Bi({sup 52}Cr,n){sup 260}Bh reaction at the Lawrence Berkeley National Laboratory's 88-Inch Cyclotron. Positive identification was made by observation of eight correlated alpha particle decay chains in the focal plane detector of the Berkeley Gas-Filled Separator. {sup 260}Bh decays with a 35{sub -9}{sup +19} ms half-life by alpha particle emission mainly by a group at 10.16 MeV. The measured cross section of 59{sub -20}{sup +29} pb is approximately a factor of four larger than compared to recent model predictions. The influences of the N = 152 and Z = 108 shells on alpha decay properties are discussed.
Date: May 7, 2007
Creator: Nelson, Sarah L.; Gregorich, Kenneth E.; Dragojevic, Irena; Garcia, Mitch A.; Gates, Jacklyn M.; Sudowe, Ralf et al.
Partner: UNT Libraries Government Documents Department

²³⁵U(n,f), ²³⁸U(n, gamma), ²³⁸U(n,f), ²³⁹Pu(n,f) Reaction Rate Measurement Calibrations at ZPPR

Description: New reference deposits for uranium-235, plutonium-239 and uranium-238 have been established with mass uncertainties of <0.2%. These new deposits replace the older reference deposits which were used during the last 17 years and improve the uncertainty of reaction rate measurements due to reference mass uncertainties by about a factor of 6. Measurements of the fission fragment absorption in 2 pi and low-geometry count rates. Two measurements of the uranium-238 capture rate in depleted uranium samples based upon the thermal cross sections of uranium-238(n, gamma), uranium-235(n,f) and plutonium-239(n,f) and based upon the americium-243 calibration technique confirm the ZPPR measurement technique within the quoted uncertainty of +/-0.5%
Date: January 1987
Creator: Poenitz, W. P.; Maddison, D. W.; Gasidlo, J. M.; Carpenter, S.G. & Armani, R. J.
Partner: UNT Libraries Government Documents Department

Alpha decay studies of {sup 189}Bi{sup m}, {sup 190}Po and {sup 180 }Pb using a rapidly rotating recoil catcher wheel system

Description: The {alpha} decays of very neutron deficient nuclei near the Z = 82 closed proton shell are of interest because they provide us with structure information that is relevant with regard to the shell model. We used a rapidly rotating recoil catcher wheel system to study the {alpha} decays of {sup 189}Bi{sup {ital m}}, {sup 190}Po, and {sup 180}Pb. The system works as follows. Recoils from the back of the target, after passing through an Al degrader placed behind the target, are stopped in 300-{mu}g/cm{sup 2} Al catcher foils fixed at the edges of the wheel. These are inclined at an angle of 20 degrees with respect to the beam to maximize the catcher efficiency while keeping the thickness that {alpha} particles must travel in order to emerge of the Al foil to a minimum. This arrangement results in an effective thickness of {approx} 900 {mu}g/cm{sup 2} for recoils, but only 150 {mu}g/cm{sup 2} for the emitted {alpha} particles. Stopped recoils are then rotated between an array of 6 Si detectors in series (solid angle of 8% of 4{pi}). Half-life information can be obtained by determining the difference in counts between the detectors. This instrument has proven to be an effective tool for the study of nuclei far from stability with half-lives in the range of 1-50 ms.
Date: September 1, 1996
Creator: Batchelder, J.C.; Toth, K.S. & Moltz, D.M.
Partner: UNT Libraries Government Documents Department

Maximum Alpha to Minimum Fission Pulse Amplitude for a Parallel-Plate and Hemispherical Cf-252 Ion-Chamber Instrumented Neutron Source

Description: In an instrumented Cf-252 neutron source, it is desirable to distinguish fission events which produce neutrons from alpha decay events. A comparison of the maximum amplitude of a pulse from an alpha decay with the minimum amplitude of a fission pulse shows that the hemispherical configuration of the ion chamber is superior to the parallel-plate ion chamber.
Date: December 7, 2000
Creator: Oberer, R.B.
Partner: UNT Libraries Government Documents Department

THE PRESENT EXPERIMENTAL AND THEORETICAL STATUS OF THE PROBLEM OF ELECTRON EJECTION IN THE ALPHA DECAY OF Po$sup 21$$sup 0$

Description: The experimental measurements of electron ejection in Po/sup 210/ decay are discussed, and the theory of the process is outlined. The order-of-magnitude discrepancy between theory and experiment that was evident a decade ago has not yet been definitively resolved. The discrepancy is ascribed to an inadequacy of the theory, in particular to the use of an asymptotic expansion in that theory. Brief mention is made of some very recent unpublished calculations by G. W. Schaefer in which a reasonable estimate of the K-ejection probability is obtained by a procedure that avoids the asymptotic expansion. (auth)
Date: January 1, 1963
Creator: Rubinson, W.
Partner: UNT Libraries Government Documents Department

New Isotope 263Hs

Description: A new isotope of Hs was produced in the reaction 208Pb(56Fe, n)263Hs at the 88-Inch Cyclotron of the Lawrence Berkeley National Laboratory. Six genetically correlated nuclear decay chains have been observed and assigned to the new isotope 263Hs. The measured cross section was 21+13-8.4 pb at 276.4 MeV lab-frame center-of-target beam energy. 263Hs decays with a half-life of 0.74 ms by alpha-decay and the measured alpha-particle energies are 10.57 +- 0.06, 10.72 +- 0.06, and 10.89 +- 0.06 MeV. The experimental cross section is compared to a theoretical prediction based on the Fusion by Diffusion model [W. J. Swiatecki et al., Phys. Rev. C 71, 014602 (2005)].
Date: March 16, 2010
Creator: Dragojevic, I.; Gregorich, K.E.; Dullmann, Ch.E.; Dvorak, J.; Ellison, P.A.; Gates, J.M. et al.
Partner: UNT Libraries Government Documents Department

HEAVY ELEMENTS RESEARCH NOTES BASED ON A SERIES OF LECTURES DELIVERED AT THE NOBEL INSTITUTE FOR PHYSICS, STOCKHOLM, SPRING, 1953

Description: Lectures are included on pile and accelerator production of transuranium nuclides, the systematics of alpha decay, and the chemistry of the heaviest elements. The chemistry lecture is given only in outline form with literature references. A table of gamma (y) for alpha decay rate calculations is included in an appendix. (M.H.R.)
Date: March 31, 1954
Creator: Rasmussen, J.O.
Partner: UNT Libraries Government Documents Department

The {alpha}-decay properties of {sup 181}Pb

Description: Following the production of {sup 181}Pb in {sup 92}Mo irradiations of {sup 90}Zr the isotope`s {alpha}-decay energy was measured to be 7065 (20) keV. This E{sub {alpha}} agrees with one previously published value for {sup 181}Pb but not with another.
Date: December 1995
Creator: Toth, K. S.; Batchelder, J. C. & Conticchio, L. F.
Partner: UNT Libraries Government Documents Department

Review of alpha-decay data from doubly-even nuclei

Description: Alpha-decay data from doubly-even nuclei throughout the periodic table are reviewed and evaluated. From these data, nuclear radius parameters are calculated by using the Preston formula for {alpha}- decay probabilities. The radius parameters for each element behave rather regularly as a function of neutron number. The show minima at the major closed shells, increase sharply for parents just above the closed shells, and decrease smoothly toward the next shell closure. The same trend is observed for {alpha} reduced widths calculated using the Rasmussen formalism. Any irregularity or large departure from this behavior indicates probable incorrect input data. This systematic behavior can also be utilized to estimate partial half- lives.
Date: September 1, 1996
Creator: Akovali, Y.A.
Partner: UNT Libraries Government Documents Department

User`s manual for the radioactive decay and accumulation code RADAC

Description: The RADAC computer code calculates radioactive decay and accumulation of decayed products using an algorithm based on the direct use of the Bateman equations and referred to here as the yield factor method. This report explains the yield factor method, gives an overview of the various modules in the RADAC code system, and describes the decay and accumulation code in detail. The RADAC code has capacity for two waste types and can accommodate up to 60 years of annual waste inputs. Decay times as high as 1 million years can be calculated. The user supplies the undecayed composition and radioactivity of the waste placed in storage each year. The code calculates the decayed composition, radioactivity, and thermal power of the accumulated waste at the end of each year and gives the results in terms of grams and curies of individual radionuclides. Calculations can be made for up to 19 waste storage sites in a single run. For each site and each waste type, calculations can be made by 1-year steps up to 60 years, by 10-year steps to 160 years, and by 6 discrete steps to 1 million years. Detailed outputs can be printed for each waste site and each time step by individual radionuclides. Summarized outputs are also available. Excluding data-preparation time, RADAC requires about 2 min to run 19 waste sites with two types of transuranic waste at each site, using a 486 DX computer with a clock speed of 33 MHz. Because RADAC uses a preselected set of decay times and does not make in-reactor calculations, it should not be viewed as a substitute for ORIGEN2. RADAC is intended for use in applications in which accumulations at the decay times provided by the code are sufficient for the user`s purposes.
Date: November 1, 1995
Creator: Salmon, R.; Loghry, S.L. & Ashline, R.C.
Partner: UNT Libraries Government Documents Department

Radiation effects and annealing kinetics in crystalline silicates, phosphates and complex Nb-Ta-Ti oxides. FInal Report

Description: Interaction of heavy particles (alpha-recoil nuclei, fission fragments, implanted ions) with ceramics is complex because they have a wide range of structure types, complex compositions and chemical bonding is variable. Radiation damage can produce diverse results, but most commonly, crystalline periodic materials become either polycrystalline or aperiodic (metamict state). We studied the transition from crystalline to aperiodic state in natural materials that have been damaged by alpha recoil nuclei in the U and Th decay series and in synthetic, analogous structure types which have been amorphized by ion implantation. Transition from crystalline to aperiodic was followed by analysis of XRD, high resolution TEM, and EXAFS/XANE spectroscopy. Use of these techniques with increasing dose provided data on an increasing finer scale as the damage process progressed.
Date: August 10, 1987
Creator: Ewing, R.C.
Partner: UNT Libraries Government Documents Department

Alpha-emitters for medical therapy workshop

Description: A workshop on ``Alpha-Emitters for Medical Therapy`` was held May 30-31, 1996 in Denver Colorado to identify research goals and potential clinical needs for applying alpha-particle emitters and to provide DOE with sufficient information for future planning. The workshop was attended by 36 participants representing radiooncology, nuclear medicine, immunotherapy, radiobiology, molecular biology, biochemistry, radiopharmaceutical chemistry, dosimetry, and physics. This report provides a summary of the key points and recommendations arrived at during the conference.
Date: December 31, 1996
Creator: Feinendegen, L.E. & McClure, J.J.
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

Evolution of collective motion in light polonium nuclei.

Description: The {gamma}-ray spectroscopy of even- and odd-mass isotopes of polonium have been studied using arrays of Ge detectors coupled to recoil-mass analyzers, including recoil-decay tagging techniques. The level energies and B(E2) branching ratios can be reproduced by theoretical frameworks which do not explicitly include proton particle-hole excitations across the Z = 82 shell, conclusions in contrast to those deduced from alpha-decay measurements.
Date: July 13, 1998
Creator: Cizewski, J. A.
Partner: UNT Libraries Government Documents Department

New Radionuclide Generator Systems for Use in Nuclear Medicine

Description: A current emphasis in nuclear medicine is to better match the physical lifetime of the radionuclides used in vivo for diagnosis and treatment to the biological lifetime of the diagnostic procedure or to minimize radiation dose to areas other than those to be treated. In many cases the biological lifetime is on the order of minutes. Since the direct production of radionuclides with half lives of minutes requires the user to be near a suitable reactor or accelerator, this study was undertaken to produce short-lived radionuclides indirectly. If a long-lived radionuclide decays into a short-lived radionuclide, quick separation of the daughter activity from the parent enables the user to have a short-lived daughter while freeing him from the constraint of proximity to a cyclotron. Systems where a short-lived daughter is separated from a long-lived parent are called radionuclide generators. Two generator systems were developed for use in nuclear medicine, one in diagnostic work and the other for therapeutic work. The yield and breakthrough characteristics were within the limits required to minimize unnecessary radiation exposure in patients. Two parent radionuclides were produced using the beams available from medium energy cyclotrons. The yield was high enough to produce generators that would be useful in clinical applications.
Date: 1979
Creator: Atcher, Robert Whitehill
Partner: UNT Libraries Government Documents Department

Study of {sup 189}Bi{sup m} {alpha} decay

Description: In a series of {sup 48}Ti bombardments of {sup 144}Sm the decay energy of the {sup 189}Bi{sup m} ({pi}s{sub 1/2}) {alpha} transition that proceeds to the {pi}s{sub 1/2} ground state of {sup 185}Tl was measured to be 7.30(4) MeV. This result establishes the excitation energy of {sup 189}Bi{sup m} as 190(40) keV rather than the adopted 92(10)-keV value. Our data thus indicate a leveling off in excitation energy at N {approx} 106 for the s{sub 1/2} intruder state in odd-A Bi isotopes.
Date: December 1995
Creator: Batchelder, J. C.; Zganjar, E. F. & Toth, K. S.
Partner: UNT Libraries Government Documents Department

Quantitative determination of {sup 252}Cf.

Description: Sealed {sup 252}Cf sources in the microCurie to milliCurie range are routinely used in industry and research. At present, no reliable analytical method is available for precise determination of the activity. Very strong sources can be analyzed by neutron counting but the error is large. The authors propose to use gamma-ray spectroscopy for such analysis. In particular, high-energy gamma rays (above 1 MeV) of fission fragments in equilibrium with the source are very convenient because they have little absorption in materials surrounding the source. They have measured the gamma/alpha ratio for {sup 252}Cf with an uncertainty of better than 5%. The experiment involved the preparation of several thin {sup 252}Cf sources, alpha pulse height analysis, determination of alpha decay rate, and the measurement of gamma singles spectrum with a well shielded germanium spectrometer. The measured ratio and the gamma ray spectroscopy of unknown samples can provide the activity of {sup 252}Cf in these samples.
Date: May 1, 2002
Creator: Ahmad, I.; Moore, E. F.; Greene, J. P.; Porter, C. E. & Felker, L. K.
Partner: UNT Libraries Government Documents Department

Lung cancer risk of low-level exposures to alpha emitters: critical reappraisal and experiments based on a new cytodynamic model

Description: Ecologic U.S. county data suggest negative associations between residential radon exposure and lung cancer mortality (LCM)-inconsistent with clearly positive associations revealed by occupational data on individual miners, but perhaps explained by competing effects of cell killing vs. mutations in alpha-exposed bronchial epithelium. To assess the latter possibility, a biologically based �cytodynamic 2-stage� (CD2) cancer-risk model was fit to combined 1950-54 age- specific person-year data on lung cancer mortality (LCM) in white females of age 40+ y in 2,821 U.S. counties (-90% never-smokers), and in 5 cohorts of underground miners who never smoked. New estimates of household annual average radon exposure in U.S. counties were used, which were found to have a significant negative ecologic association with 1950-54 LCM in U.S. white females, adjusted for age and all subsets of two among 21 socioeconomic, climatic and other factors considered. A good CD2 fit was obtained to the combined residential/miner data, using biologically plausible parameter values. Without further optimization, the fit also predicted independent inverse dose-rate effects shown (for the first time) to occur in nonsmoking miners. Using the same U.S. county-level LCM data, a separate study revealed a positive ecologic association between LCM and bituminous coal use in the U.S., in agreement with epidemiological data on LCM in women in China. The modeling results obtained are consistent with the CD2-based hypothesis that residential radon exposure has a nonlinear U-shaped relation to LCM risk, and that current linear no-threshold extrapolation models substantially overestimate such risk. A U-shaped dose-response corresponds to a CD2-model prediction that alpha radiation kills more premalignant cells than it generates at low exposure levels, but not at higher levels. To test this hypothesis, groups of Japanese medaka (ricefish minnows) were exposed for 10 to 14 weeks to different concentrations of aqueous radon; histological and quantitative-morphometry analysis of proliferative (premalignant) ...
Date: February 20, 1999
Creator: Bogen, K T
Partner: UNT Libraries Government Documents Department

Nuclear Thermodynamics of the Heaviest Elements. II

Description: The masses of the isotopes of the heaviest elements have been calculated from known decay data in the region, extended by means of decay energies calculated from closed decay-energy cycles and estimated from the systematics of alpha and beta decay energies. The absolute values of the masses are based on the mass-spectrometrically determined mass of Pb{sup 208} and a few measured neutron binding energies. The half-life systematics of alpha decay and spontaneous fission are also presented, and some predictions of the properties of as yet undiscovered nuclides are made.
Date: October 1, 1957
Creator: Foreman Jr., Bruce M. & Seaborg, Glenn T.
Partner: UNT Libraries Government Documents Department