Nuclear Data Sheets最新文献

Experimental nuclear spectroscopic data are evaluated for 12 known nuclides of mass number A=44 (Si, P, S, Cl, Ar, K, Ca, Sc, Ti, V, Cr, Mn). Detailed evaluated information are presented for each reaction and decay. Recommended values combining all available data are provided for all spectroscopic properties of each level, γ-ray, and decay radiation. No excited states have yet been identified in ⁴⁴Si, ⁴⁴P, ⁴⁴Cr, and ⁴⁴Mn. Information for excited states in ⁴⁴Cl and ⁴⁴V are limited. Nuclides of ⁴⁴S, ⁴⁴Ar and ⁴⁴K have been studied via only a few reactions and decays, while ⁴⁴Ca, ⁴⁴Sc and ⁴⁴Ti are the most investigated nuclides through various reactions and decays. Evaluators note that the half-life of the g.s. of ⁴⁴S has been measured independently, with fairly good statistics, in three references, most precise being 100 ms 1 by 2004Gr20, but this value is in disagreement with the values of 125.5 ms 25 and 119 ms 6 by 2022Tr03, and 123 ms 10 by 1995So03. We adopted the unweighted average of this discrepant dataset. Another outstanding issue is that of the β⁺-delayed proton decay of ⁴⁴Cr g.s. to ⁴⁴V, where the T=2, 0⁺ IAS state in ⁴⁴V is expected to be strongly populated by a superallowed β transition, but has not been definitely identified as discussed in detail by 2020Fu05. A detailed study of ⁴⁴Cr decay is required to unravel the status of the T=2, 0⁺ IAS state in ⁴⁴V. This work supersedes earlier ENSDF evaluations of A=44 by 2011Ch39 and 1999Ca45.

⁶⁵Zn is a common calibration source, moreover used as a radioactive tracer in medical and biological studies. In many cases, γ-spectroscopy is a preferred method of ⁶⁵Zn standardization, which relies directly on the branching ratio of Jπ(⁶⁵Zn) = 5/2⁻ → Jπ(⁶⁵Cu) = 5/2⁻ via electron capture (EC*). We measure the relative intensity of this branch to that proceeding directly to the ground state (EC⁰) using a novel coincidence technique, finding I_EC0/IEC* = 0.9684 ± 0.0018. Re-evaluating the decay scheme of ⁶⁵Zn by adopting the commonly evaluated branching ratio of I_β+ = 1.4271(7)% we obtain IEC* = (50.08 ± 0.06)%, and I_EC0 = (48.50 ± 0.06)%. The associated 1115 keV gamma intensity agrees with the previously reported NNDC value, and is now accessible with a factor of ∼2 increase in precision. Our re-evaluation removes reliance on the deduction of this gamma intensity from numerous measurements, some of which disagree and depend directly on total activity determination. The KDK experimental technique provides a new avenue for verification or updates to the decay scheme of ⁶⁵Zn, and is applicable to other isotopes.

Available information pertaining to the nuclear structure of ground and excited states for all known nuclei with mass numbers A=245 have been compiled and evaluated. The adopted level and decay schemes, as well as the detailed nuclear properties and configuration assignments based on experimental data, are presented for these nuclides. When there are insufficient data, expected values from systematics of nuclear properties and/or theoretical calculations are utilized. Unexpected or discrepant experimental results are also noted. Since the last evaluation, new rotational bands in ²⁴⁵Pu have been observed to high spin from transfer reaction ²⁴⁴Pu(²⁰⁹Bi, ²⁰⁸Biγ) by 2014Ho16. While in ²⁴⁵Am, the ²⁴⁹Bk α decay measurements by 2013Ah03 added a new rotational band based on π3/2[521] configuration. The ²⁴⁵Pu β⁻ decay scheme is basically what was proposed in the late 60's and 47 γ rays have still not been placed. In ²⁴⁵Cm, precise alpha energies and intensities were measured by 2015Ah03 in ²⁴⁹Cf α decay. Their reported alpha energies of the main α group were about 2 keV lower than in the previous evaluation. The spin and parity of the g.s. of ²⁴⁵Es is still ambiguous as more detailed information on the decay is needed. With the production of ²⁴⁹No via fusion evaporation reaction by groups in Dubna and GSI, it's alpha decay was studied and some properties of the daughter ²⁴⁵Fm were published and included in this evalaution. Information on the other nuclides is scarce and not much has been investigated since the last evaluation. A summary and compilation of the discovery of the various nuclides in this mass region is given in: 2013Fr02 (²⁴⁵Pu, ²⁴⁵Am, ²⁴⁵Cm, ²⁴⁵Bk, ²⁴⁵Cf), 2011Me01 (²⁴⁵Es), and 2013Th02 (²⁴⁵Md, ²⁴⁵Fm).

The experimental reaction and decay studies producing nuclei in the A=251 mass chain have been reviewed. Data on elements from uranium (Z=92) to nobelium (Z=102) are included, and level and decay schemes are presented for these nuclides. This work supersedes the previous evaluation for this mass chain (2013Br09).

Experimental nuclear spectroscopic data are evaluated for 12 known nuclides of mass number=71 (Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Kr). Detailed compiled and evaluated information is presented for each reaction and decay experiment. The β⁻n decay of ⁷²Co to ⁷¹Ni is included in this work, while for β⁻n decay of ⁷¹Co to ⁷⁰Ni, consult Nuclear Data Sheets for A=70 (2016Gu11) or the ENSDF database for ⁷⁰Ni. 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. Excited-states have not yet been identified in ⁷¹Mn, ⁷¹Fe, and ⁷¹Kr, with the ground-state half-life remaining unknown only for ⁷¹Mn; data for excited states in ⁷¹Co and ⁷¹Ni are very limited; ⁷¹Ga, ⁷¹Ge and ⁷¹As are the most extensively studied nuclides via various reactions and decays, followed by ⁷¹Cu, ⁷¹Zn, ⁷¹Se, and ⁷¹Br, however, except for ⁷¹Ge, the decay schemes of all other nuclides are considered as incomplete due to a large gap between the decay Q-value and the highest observed level. This work supersedes earlier evaluations of A=71 by 2011Ab01.

Production cross sections of light positron emitters ¹¹C (t_1/2=20.36 min), ¹³N (t_1/2=9.97 min) and ¹⁵O (t_1/2=122 s) have been measured for proton-induced reactions on the main relevant constituents of the human body (C, N and O) from threshold up to 200 MeV of proton incident energy. This has been accomplished by means of two complementary experiments at the clinical proton treatment centers WPE (Essen) and HIT (Heidelberg), both in Germany. In the first case, the multi-foil activation technique was combined with PET imaging, a methodology previously developed at CNA (Seville, Spain). In the second experiment, aimed at energies below 50 MeV, the activation of single foils was measured with conventional LaBr₃ detectors. In both cases the IAEA monitor reaction ^natCu(p,x)⁶³Zn data was used for validation purposes.

The most complete and accurate set of excitation functions for the production of light-positron emitters ¹¹C, ¹³N and ¹⁵O in proton induced reactions on human tissue up to 200 MeV is presented. These data are needed for nuclear reaction model development and are extremely important to improve the accuracy of the PET range verification in proton radiotherapy. Seven excitation functions have been measured: ¹²C(p,x)¹¹C, ¹⁴N(p,x)¹¹C, ¹⁴N(p,x)¹³N, ¹⁴N(p,γ)¹⁵O, ¹⁶O(p,x)¹¹C, ¹⁶O(p,x)¹³N and ¹⁶O(p,x)¹⁵O up to 200 MeV of proton incident energy.