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McCutchan, Elizabeth A.

Publications and source records attributed to McCutchan, Elizabeth A..

7 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Determination of the spins and parities for the 0$^{+}_{4}$ and 0$^{+}_{5}$ states in 100 Zr

Here, two 0 + states at 1294.5 and 1774.0 keV, together with three 2 + and one 4 + levels, were identified or unambiguously spin-parity assigned for the first time in 100 Zr utilizing γ-ray spectroscopy and γ–γ angular correlation techniques with the Gammasphere spectrometer, following the β – decay of neutron-rich, mass-separated 100,100m Y isotopes. Comparisons with recent Monte Carlo shell-model calculations indicate that these two states are candidates for the bandhead of a sequence in a shape-coexisting spherical minimum predicted to be located around ≈1500 keV. According to the measured relative B(E2) relative transition probabilities, the 0$^+_5$ state exhibits decay properties which more closely align with those predicted for a spherical shape, while the 0$^+_4$ level is suggested to be associated with a weakly deformed shape similar to one related to the 0$^+_2$ state.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Compilation and Evaluation of Beta-Delayed Neutron Emission Probabilities and Half-Lives for Z > 28 Precursors

We present a compilation and evaluation of experimental β-delayed neutron emission probabilities (P n ) and half-lives (T 1/2 ) for known or potential β-delayed neutron precursors with atomic number Z >28 ( 73 Cu – 233 Fr). This article includes the recommended values of both of these quantities, together with a compilation of experimental measurements when available. Some notable cases, as well as proposed standards forβ-delayed neutron measurements are also discussed. Evaluated data has also been compared to systematics using three different approaches.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Nuclear Data Sheets for A=212

Spectroscopic data for all nuclei with mass number A=212 have been evaluated and the corresponding level schemes from radioactive decay and reaction studies are presented. Highlights from this evaluation include the first observation of 212 Hg by 2010Al24 and the first measurement of the ground state half-life by 2012Be28and 2016Ca25. The first measurement of the β - decay of 212 Tl populating excited states in 2 12 Pb has been per-formed by 2014Mo02. Knowledge of excited levels and their half-lives in 212 Po has been significantly extended in the transfer reaction studies of 2010As01, 2010As03 and 2016Ko03, 2017Ko38. A new (9 - )isomer which α decays in 212 At was observed by 2007Ku30. The level scheme of 212 Rn was significantly extended through the(HI,xnγ) reaction studies of 2009Dr12 and 2008Dr01. New levels in 212 Ra were identified in a transfer reaction experiment by 2018Pa04. Finally, the α decay of both the ground state and an isomer in 216 U populating 212 Thwas reported for the first time by 2015Ma37 and 2015De22

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

First candidates for $γ$ vibrational bands built on the [ 505 ] 11 / 2 - neutron orbital in odd- A Dy isotopes

In this work, rotational structures have been measured using the Jurogam II and GAMMASPHERE arrays at low spin following the Gd 155 ( α , 2 n ) Dy 157 and Nd 148 ( C 12 , 5 n ) Dy 155 reactions at 25 and 65 MeV, respectively. We report high- K bands, which are conjectured to be the first candidates of a K π = 2 + γ vibrational band, built on the [ 505 ] 11 / 2 - neutron orbital, in both odd- A Dy 155 , 157 isotopes. The coupling of the first excited K = 0 + states or the so-called β vibrational bands at 661 and 676 keV in Dy 154 and Dy 156 to the [ 505 ] 11 / 2 - orbital, to produce a K π = 11 / 2 - band, was not observed in both Dy 155 and Dy 157 , respectively. The implication of these findings on the interpretation of the first excited 0 + states in the core nuclei Dy 154 and Dy 156 are also discussed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Multinucleon transfer in the interaction of 977 MeV and 1143 MeV Hg 204 with Pb 208

A previous study of symmetric collisions of massive nuclei has shown that current models of multinucleon transfer (MNT) reactions do not adequately describe the transfer product yields. To gain further insight into this problem, we have measured the yields of MNT products in the interaction of 977 (E/A = 4.79 MeV) and 1143 MeV (E/A = 5.60 MeV) 204 Hg with 208 Pb. We find that the yield of multinucleon transfer products are similar in these two reactions and are substantially lower than those observed in the reaction of 1257 MeV (E/A = 6.16 MeV) 204 Hg+ 198 Pt. We compare our measurements with the predictions of the GRAZING-F, dinuclear systems (DNS), and improved quantum molecular dynamics (ImQMD) models. We report that for the observed isotopes of the elements Au, Hg, Tl, Pb, and Bi, the measured values of the MNT cross sections are orders of magnitude larger than the predicted values. Furthermore, the various models predict the formation of nuclides near the N = 126 shell, which are not observed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗