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Half-Life of Polonium

Description: Abstract: "The half-life of polonium has been measured by a calorimetric method using samples several thousand times larger than have been previously available. The value is found to be 138.3 +/- 0.1% days."
Date: September 9, 1946
Creator: Beamer, William H. & Easton, William E.
Partner: UNT Libraries Government Documents Department

The Half Life of Am²⁴³

Description: This report calculates the alpha half-life of americium-243 and reporting a measurement error.
Date: 1953
Creator: Diamond, Herbert; Fields, Paul R.; Mech, Joseph; Inghram, Mark Gordon & Hess, David C.
Partner: UNT Libraries Government Documents Department

THE ROLE OF THE CYCLOTRON IN MEDICAL RESEARCH

Description: The uses of radioactive isotopes in medical research can be conveniently divided into three principal categories; namely, the applications as tracers for the study of metabolic phenomena, as diagnostic aids in clinical medicine, and finally their role in therapy. Frequently radioisotopes available from the chain-reacting pile do not have a sufficient degree of specific activity for satisfactory use. A number of radioisotopes which can be produced with high specific activity in the pile possess half-lives too short to be of any practical value. Then, there are a few cases in which the desired radioisotope may be made in the pile with high specific activity, but concomitantly there is formed another radioisotope of the same element whose half-life is of such duration as to render its use hazardous in man. Finally, there are several elements of biological and medical interest whose radioactive isotopes can be produced only by the cyclotron.
Date: April 19, 1950
Creator: Hamilton, Joseph G.
Partner: UNT Libraries Government Documents Department

Radiation of Pu²⁴³

Description: "The radiations of Pu²⁴³ were studied with beta and gamma scintillation spectrometers alone and in coincidence. An incomplete disintegration scheme is deduced which leads to a total beta disintegration energy of 560 kev. A half-life of 4.98 ± 0.02 hours was observed."
Date: October 1952
Creator: Engelkemeir, D. W.; Fields, Paul R. & Huizenga, John R.
Partner: UNT Libraries Government Documents Department

EFFECTIVE HALF-LIFE OF CESIUM-137 IN VARIOUS ENVIRONMENTAL MEDIA AT THE SAVANNAH RIVER SITE

Description: During the operational history of the Savannah River Site (SRS), many different radionuclides have been released from site facilities into the SRS environment. However, only a relatively small number of pathways, most importantly {sup 137}Cs in fish and deer, have contributed significantly to doses and risks to the public. The “effective” half-lives (T{sub e}) of {sup 137}Cs (which include both physical decay and environmental dispersion) in Savannah River floodplain soil and vegetation and in fish and white-tailed deer from the SRS were estimated using long-term monitoring data. For 1974–2011, the T{sub e}s of {sup 137}Cs in Savannah River floodplain soil and vegetation were 17.0 years (95% CI = 14.2–19.9) and 13.4 years (95% CI = 10.8–16.0), respectively. These T{sub e}s were greater than in a previous study that used data collected only through 2005 as a likely result of changes in the flood regime of the Savannah River. Field analyses of {sup 137}Cs concentrations in deer collected during yearly controlled hunts at the SRS indicated an overall T{sub e} of 15.9 years (95% CI = 12.3–19.6) for 1965–2011; however, the T{sub e} for 1990–2011 was significantly shorter (11.8 years, 95% CI = 4.8–18.8) due to an increase in the rate of {sup 137}Cs removal. The shortest T{sub e}s were for fish in SRS streams and the Savannah River (3.5–9.0 years), where dilution and dispersal resulted in rapid {sup 137}Cs removal. Long-term data show that T{sub e}s are significantly shorter than the physical half-life of {sup 137}Cs in the SRS environment but that they can change over time. Therefore, it is desirable have a long period of record for calculating Tes and risky to extrapolate T{sub e}s beyond this period unless the processes governing {sup 137}Cs removal are clearly understood.
Date: December 12, 2013
Creator: Jannik, T.; Paller, M. & Baker, R.
Partner: UNT Libraries Government Documents Department

Measurement of the {sup 44}Ti half-life and its significance for supernova.

Description: In 1998, we reported the three-laboratory measurement of the {sup 44}Ti half-life which was determined relative to the well known value (5.2714 {+-} 0.0005 yr) of the {sup 60}Co half-life. We have continued the measurement at Argonne and Jerusalem and inclusion of data points for additional two years does not change our published value of 59.0 {+-} 0.6 yr.
Date: August 28, 1999
Creator: Ahmad, I.; Greene, J. P.; Kutschera, W. & Paul, M.
Partner: UNT Libraries Government Documents Department

TABLE OF RADIOISOTOPES ARRANGED ACCORDING TO HALF-LIFE

Description: The tabulated data on radioisotopes are taken directly from the General Electric Chart of the Nuclides, Fifth Edition. The half lives, decay particles and energies, gamma energies, and total energy or mass are included in the table. (J.E.D.)
Date: December 1, 1957
Creator: Daniels, E. comp.
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

On Double-Beta Decay Half-Life Time Systematics

Description: Recommended 2{beta}(2{nu}) half-life values and their systematics were analyzed in the framework of a simple empirical approach. T{sub 1/2}{sup 2{nu}} {approx} 1/E{sup 8} trend has been observed for {sup 128,130}Te recommended values. This trend was used to predict T{sub 1/2}{sup 2{nu}} for all isotopes of interest. Current results were compared with other theoretical and experimental works.
Date: April 14, 2010
Creator: Pritychenko, B.
Partner: UNT Libraries Government Documents Department

The Half-Lives of Aluminum25 and Aluminum26

Description: The availability of separated isotopes of Mg makes it easy to determine the half life of Al{sup 26}, a member of the Wigner series which has long been suspected to have a half life of approximately 7 seconds, but which has not been confirmed because of the masking 7 second activity of Al{sup 26}. Mg{sup 24}, Mg{sup 25} and Mg{sup 26} (in the form of MgO) have been bombarded with protons from the Berkeley Linear Accelerator, with the following results: (1) Mg{sup 24} yields an activity of approximately 23 seconds half life, presumably due to Na{sup 21} from the reaction Mg{sup 24}(p,a)Na{sup 21}; (2) the Mg{sup 25} yields an activity of approximately 8 seconds half life, which they assign to the reaction Mg{sup 25}(p,n)Al{sup 25}; and (3) The Mg{sup 26} yields an activity of approximately 6 seconds half life, assigned to Al{sup 26} according to a similar reaction. It seems probable therefore that the 7 seconds half life normally given for Al{sup 26} is a mixture of these two activities.
Date: April 24, 1948
Creator: Bradner, Hugh & Gow, J.D.
Partner: UNT Libraries Government Documents Department

THE FIRST ISOLATION OF AMERICIUM IN THE FORM OF PURE COMPOUNDS - THE SPECIFIC ALPHA-ACTIVITY AND HALF-LIFE OF Am241

Description: The microgram scale isolation and preparation of pure compounds of americium is described. Data are presented to show that the alpha-half-life of the isotope Am{sup 241} is 490 {+-} 14 years. The absorption spectrum of Am(III) in 1M nitric acid in the range 3500-8000 mu is given. The wave lengths of 10 of the most prominent lines in the copper spark emission spectrum of americium are given to the nearest 0.01 {angstrom}. Evidence is presented to show that the potential for the Am(III)-Am(IV) couple in acid solution is more negative than -2v and that the potential for the Am(II)-Am(III) couple is more positive than +0.9v.
Date: July 20, 1950
Creator: Cunningham, B.B. & Asprey, L.B.
Partner: UNT Libraries Government Documents Department

Nuclear Reactions of Arsenic with 190 Mev Deuterons

Description: Isotopes formed in the bombardment of {sub 33}As{sup 75} with 190 Mev deuterons range in atomic number up to 24 (or more) mass units lighter than As{sup 75}. Identification of these isotopes was based on chemical behavior and half-life determination. Relative yields have been calculated and show that 80% of the observed reactions produce isotopes within 8 mass units of As{sup 75}. Three new isotopes have been observed: 9.5 d. Se{sup 72} (K), 44 m, Se{sup 71} ({beta}{sup +}), and 52 m, As{sup 71} ({beta}{sup +}).
Date: January 21, 1948
Creator: Hopkins Jr, H.H. & Cunningham, B.B.
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

ORIGEN-S Decay Data Library and Half-Life Uncertainties

Description: The results of an extensive update of the decay data of the ORIGEN-S library are presented in this report. The updated decay data were provided for both the ORIGEN-S and ORIGEN2 libraries in the same project. A complete edit of the decay data plus the available half-life uncertainties are included in Appendix A. A detailed description of the types of data contained in the library, the format of the library, and the data sources are also presented. Approximately 24% of the library nuclides are stable, 66% were updated from ENDF/B-VI, about 8% were updated from ENSDF, and the remaining 2% were not updated. Appendix B presents a listing of percentage changes in decay heat from the old to the updated library for all nuclides containing a difference exceeding 1% in any parameter.
Date: January 1, 1998
Creator: Hermann, O.W.
Partner: UNT Libraries Government Documents Department

Proton radioactivity studies at the FMA

Description: A double sided silicon strip (DSSD) setup is installed at the Argonne National Laboratory recoil separator FMA. Ground state proton emitters {sup 146,147}Tm, {sup 160}Re, {sup 156}Ta, {sup 150,151}Lu were produced in a series of test experiments. Improved T{sub 1/2} values were obtained for {sup 147}Tm, {sup 160}Re, and {sup 156}Ta. Improved alpha T{sub 1/2} value of (13.2 {plus_minus} 1.1) ms was obtained for {sup 161}Re. In a search of new proton radioactivities a (5 {plus_minus} 2)% proton decay branch with E{sub p} = (1345 {plus_minus} 13) keV for {sup 161}Re was found.
Date: December 31, 1995
Creator: Penttila, H.; Davids, C.N. & Woods, P.J.
Partner: UNT Libraries Government Documents Department

Nuclear structure information derived from proton radioactivity measurements

Description: Proton decay presents an opportunity to obtain nuclear structure information for a nucleus situated beyond the proton drip line. This relatively rare decay mode is a quantum tunneling phenomenon where the decay rate is determined by a delicate interplay between the Coulomb and centrifugal terms of the nuclear potential. Ground-state proton emitters have been discovered for the odd-Z elements having Z = 51--55, 63, and 67--83. Recent results on proton radioactivity are described. Nuclear structure information such as spins, single particle orbital orderings, spectroscopic factors, and mass excesses have been obtained for a number of spherical proton emitters. New results on deformed proton emitters are discussed.
Date: October 1, 1997
Creator: Davids, C.N.
Partner: UNT Libraries Government Documents Department

High-field penning-malmberg trap: confinement properties and use in positron accumulation

Description: This dissertation reports on the development of the 60 kG cryogenic positron trap at Lawrence Livermore National Laboratory, and compares the trap`s confinement properties with other nonneutral plasma devices. The device is designed for the accumulation of up to 2{times}10{sup 9} positrons from a linear-accelerator source. This positron plasma could then be used in Bhabha scattering experiments. Initial efforts at time-of-flight accumulation of positrons from the accelerator show rapid ({approximately}100 ms) deconfinement, inconsistent with the long electron lifetimes. Several possible deconfinement mechanisms have been explored, including annihilation on residual gas, injection heating, rf noise from the accelerator, magnet field curvature, and stray fields. Detailed studies of electron confinement demonstrate that the empirical scaling law used to design the trap cannot be extrapolated into the parameter regime of this device. Several possible methods for overcoming these limitations are presented.
Date: September 1, 1997
Creator: Hartley, J.H.
Partner: UNT Libraries Government Documents Department

TABLE OF RADIOACTIVE ELEMENTS.

Description: For those chemical elements which have no stable nuclides with a terrestrial isotopic composition, the data on radioactive half-lives and relative atomic masses for the nuclides of interest and importance have been evaluated and the recommended values and uncertainties are listed.
Date: June 29, 2001
Creator: HOLDEN,N.E.
Partner: UNT Libraries Government Documents Department

Proton Emission from Gamow Resonance

Description: We demonstrated that it is possible to calculate the complex energy of the deformed Gamow state with a precision that is high enough so that the half-life calculated from the imaginary part of the energy is meaningful. We also performed a comparison between non-adiabatic and adiabatic calculations. It can be concluded that, in many cases, the corrected adiabatic treatment cannot be used as a substitute for the full non-adiabatic calculations.
Date: October 19, 2001
Creator: Vertse, T.
Partner: UNT Libraries Government Documents Department