Nuclear Data Sheets最新文献

Most evaluated elemental fission product yield distributions are not experimentally measured. Instead, the majority of evaluated distributions are based on analytic expressions of the Zp-model for relevant cumulative yields. Here we report independent elemental fission product yield distributions of a ²³⁵U target for incident neutron energies ranging from 0.11 MeV through 92.4 MeV. Atomic numbers are calculated by an approach that combines a 2E analysis with a stopping force analysis method, developed within this paper. These analyses are applied to more than 6.1 × 10⁶ fission fragment ionization tracks captured within the NIFFTE (Neutron Induced Fission Fragment Tracking Experiment) collaboration fission time projection chamber (fissionTPC). A 3-Z resolution was obtained with the fissionTPC spatial and energy resolutions. Tabulated results are presented for the atomic yield and experimentally derived Zp values as a function of pre-neutron-emission fragment masses for the complete range of incident neutron energies. The stopping-force-derived Zp values tend to support the unchanged charge distribution theory within uncertainty.

Experimental nuclear spectroscopic data are evaluated for 11 known nuclides of mass 31 (F, Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K). Detailed evaluated information is presented for each reaction and decay experiment. Combining all the available data, recommended values are provided for energies, spins and parities, and half-lives of levels, with energies, branching ratios and multipolarities of γ radiations, and characteristics of β and α radiations in radioactive decays. ³¹P is the most extensively studied one among all nuclides via various reactions and decays, followed by ³¹S, ³¹Si, ³¹Mg and ³¹Al. Information for excited states in ³¹Ne, ³¹Na, ³¹Cl, ³¹Ar and ³¹K are limited; no excited states have yet been identified in ³¹F, even its ground-state half-life is unknown. Significant new data have become available for the structure of ³¹S, with its relevance to astrophysical applications. This work supersedes the earlier evaluation of A=31 by 2013Ou01, with literature cutoff date of Feb 15, 2013.

Evaluated spectroscopic data and level schemes from radioactive decay and nuclear reaction studies are presented for ¹⁸⁶Lu, ¹⁸⁶Hf, ¹⁸⁶Ta, ¹⁸⁶W, ¹⁸⁶Re, ¹⁸⁶Os, ¹⁸⁶Ir, ¹⁸⁶Pt, ¹⁸⁶Au, ¹⁸⁶Hg, ¹⁸⁶Tl, ¹⁸⁶Pb, ¹⁸⁶Bi, and ¹⁸⁶Po. This evaluation for A=186 supersedes the earlier evaluation 2003Ba44 by C. M. Baglin. Highlights of this evaluation are the following: ¹⁸⁶Re: Revised %ε and %β⁻ branches. New values are almost same as of the earlier ones. Adopted improved level energy for the long-lived (8⁺) isomer at 148.2 keV 5 based on the study reported in 2015Ma60 (¹⁸⁷Re(n, 2nγ)) compared to 149 keV 7 in previous evaluation (2003Ba44). ¹⁸⁶Hg: Discrepancies in the level schemes between 1992Po01 and 1993Ma02 remain to resolve experimentally, arise primarily due to the assigned multipolarity of the ≈607 keV γ transition between the 1228 keV bandhead and the 2⁺ 621 keV level. See general comments in Adopted Levels, Gammas dataset. ¹⁸⁶Tl: From α decay studies, 2020St11 propose spin-parity (2⁻) for the g.s. and (7⁺) for the excited level at 0.0+x of level energy of 77 keV 56. From mass measurements, 2014Bo26 propose the (7⁻) level energy of 20 keV 40 earlier.

Information on the production, identification, half-lives and decay modes for experimentally known nuclides with mass numbers of 267, 271, 275, 279, 283, 287, and 291, along with attempts to observe nuclides with mass numbers of 295 and 299, are presented along with the recommended values. Data here supersede data from the previous evaluation in this region, 2005Gu33. Since the previous evaluation many new and conclusive experiments have explored the region of superheavy nuclei, thus significantly expanding our knowledge of the nuclear chart in this area.

Experimental nuclear structure and decay data are evaluated for all of 10 known nuclides of mass 236 (Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf). For each nuclide, detailed evaluated spectroscopic information is presented in each reaction and decay, and the best values combining all available data are recommended for level properties, γ and β radiations, and other spectroscopic properties in the Adopted Levels and Gammas. The present evaluation supersedes the earlier one on A=236 by E. Browne, J. K. Tuli (2006Br20), published in Nuclear Data Sheets 107, 2641 (2006).

Information on the production, identification, half-lives and decay modes for experimentally known nuclides with mass numbers of 269, 273, 277, 281, 285, 289, and 293 are presented along with the recommended values. Data here supersede data from the previous evaluation in this region, 2005Gu33. Since the previous evaluation many new and conclusive experiments have explored the region of superheavy nuclei, thus significantly expanding our knowledge of the nuclear chart in this area.