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Bibliographic Details
Main Authors: Giha, N. P., Marin, S., Tolstukhin, I. A., Oberling, M. B., Knaack, R. A., Mueller-Gatermann, C., Korichi, A., Bhatt, K., Carpenter, M. P., Fougères, C., Karayonchev, V., Kay, B. P., Lauritsen, T., Seweryniak, D., Watwood, N., Duke, D. L., Mosby, S., Montoya, K. B., Connolly, D. S., Loveland, W., Hernandez, I. E., Clarke, S. D., Pozzi, S. A., Tovesson, F.
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2412.15898
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Table of Contents:
  • We measure the average spin of $^{144}$Ba, a common fragment produced in $^{252}$Cf(sf), as a function of the total kinetic energy (TKE). We combined for the first time a twin Frisch-gridded ionization chamber with a world-class $γ$-ray spectrometer that was designed to measure high-multiplicity $γ$-ray events, Gammasphere. The chamber, loaded with a $^{252}$Cf(sf) source, provides a fission trigger, the TKE of the fragments, the approximate fragment masses, and the polar angle of the fission axis. Gammasphere provides the total $γ$-ray yield, fragment identification through the tagging of decay $γ$ rays, and the feeding of rotational bands in the fragments. We determine the dependence of the average spin of $^{144}$Ba on the fragments' TKE by correlating the fragment properties with the distribution of discrete levels that are fed. We find that the average spin only changes by about $0.5$ $\hbar$ across the TKE range of 158-203 MeV. The virtual independence of the spin on TKE suggests that spin is not solely generated through the statistical excitation of rotational modes, and more complex mechanisms are required.