Evaluated spectroscopic data and level schemes are presented for 166(Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, and Pt) isotopes, based on the measured decay and nuclear reaction studies. This evaluation for A=166 supersedes the earlier one by C.M. Baglin ([2008Ba14]). About 540 new gamma transitions and 200 excited levels are adopted in this evaluation from new measurements, compared to those in the previous evaluation. The new gammas and levels mostly belong to 166Er, 166Ta, 166Re, and 166Os nuclides, studied mainly by (HI,x) reactions and decay (mostly 166Ho to 166Er). In 166Tm, the energy of the isomeric state with t1/2=348 ms is not known yet, there are different assumptions in [1996Dr07] and [2002Ca46]. Also there is an ambiguity in 166Re, whether the unknown level labeled as 0.0+x represents the ground state or an excited state. New measurements are needed to resolved the issues of these low lying levels in 166Tm and 166Re.Throughout this evaluation, rotational band parameters are calculated from the standard energy equation:E(J,K)=E0+A[J(J+1)+δK,1/2(−1)J+1/2a(J+1/2)]+BJ2(J+1)2 where A is given in keV, B is given in eV, and the decoupling constant a is dimensionless. When not explicitly stated, B is assumed to be 0. The minimum number possible of the lowest energy levels was used to calculate each set of parameters, unless noted otherwise.
This work presents a comprehensive and critical evaluation of experimental nuclear spectroscopic data from reactions and decays for all 11 known nuclides with mass number A=220 (Pb, Bi, Po, At, Rn, Fr, Ra, Ac, Th, Pa, and Np). Recommended values are produced for level energies, spins and parities, half-lives, and radiation properties including energies, branching ratios, and multipolarities of γ rays, as well as characteristics of β and α radiation decays, based on all available experimental data. This work supersedes previous A=220 evaluations: 2011Br05, 1997Ar04, 1986Ma45, 1976El04.
(Received 2025; April 2026) Abstract: This work presents a comprehensive and critical evaluation of experimental nuclear spectroscopic data from reactions and decays for all 11 known nuclides with mass number 35 (Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K, Ca). Recommended values are produced for level energies, spins and parities, half-lives, and radiation properties including energies, branching ratios, and multipolarities of y rays, as well as characteristics of /3 radiation decays, based on a rigorous assessment of all available experimental data. Discrepancies among existing results are carefully addressed. This work supersedes earlier full evaluations of A=35 published by 2011Ch48, 1990En08 (also 1998En04 update) and 1978En02.
The integral gamma and electron spectra emitted by fission products, also known as delayed gamma and electron spectra, were measured at Oak Ridge National Laboratory in the 1970s for the thermal-neutron induced fission of 235U and 239,241Pu. Scintillator detectors were used to measure these spectra, data used later on to obtain decay heat values - that is, the spectra mean values per unit time as function of time - work that was published in the Nuclear Science and Technology journal; the spectral data, however, was only published in laboratory reports. In this work, we analyze the gamma spectra data using modern methods and nuclear databases to reveal the signature of individual fission products as well as to gauge the performance of the ENDF/B-VIII.0 decay data sub-library, concluding about possible future enhancements in predictive capabilities.
Over the last decade, there has been significant improvement in the understanding and modeling of the decay of fission fragments by both prompt and delayed emission. These model improvements open the door for performing consistent evaluations across multiple fission observables, providing not only mean values but also covariances between observables. One such model is the Hauser-Feshbach Fission Fragment Decay model implemented in BeoH, which uses distributions of initial conditions of fission fragments to perform a Hauser-Feshbach decay for prompt neutron and γ-ray emission and evaluated decay data to calculate cumulative fission product yields. This manuscript describes a new evaluation procedure for independent and cumulative fission product yields, including full correlations among the fission products. We use a Bayesian Kalman filter to fit both experimental cumulative fission product yields and those from the ENDF/B-VIII.0 evaluated library, producing mean values and covariances. In addition to comparing the fission products from these optimizations, we calculate prompt and delayed neutron and γ-ray multiplicities using the fitted parameters and compare to some available experimental data. We see reasonable agreement, even when these quantities are not included in the optimization.
