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γ -ray spectroscopy of Tl209

Authors :
P. Chowdhury
W. Loveland
A. D. Ayangeakaa
B. M. S. Amro
C. J. Lister
John P. Greene
W. B. Walters
R. Yanez
J. S. Barrett
J. L. Harker
M. P. Carpenter
R. V. F. Janssens
S. Zhu
E. A. McCutchan
C. J. Chiara
Alejandro Sonzogni
T. Lauritsen
Source :
Physical Review C. 95
Publication Year :
2017
Publisher :
American Physical Society (APS), 2017.

Abstract

States in $^{209}\mathrm{Tl}$ were populated using a multinucleon transfer reaction with a $^{136}\mathrm{Xe}$ beam impinging on a thick $^{208}\mathrm{Pb}$ target at $E=785$ MeV. The beam was pulsed at 825-ns intervals in order to perform isomer decay spectroscopy. The known ${J}^{\ensuremath{\pi}}=17/{2}^{+}$ isomer in $^{209}\mathrm{Tl}$ was located at 1228(4) keV and measured to have a half-life of ${T}_{1/2}=146(10)$ ns. A second isomer with ${J}^{\ensuremath{\pi}}=13/{2}^{+}$ was found to have ${T}_{1/2}=14(5)$ ns. The previously suggested low-energy X and Y transitions were found to have energies 57(2) and 47(2) keV respectively, while the measurement of conversion coefficients and a new decay path make the spin assignments below the isomers experimentally firm. Correlating the delayed $\ensuremath{\gamma}$ transitions with the prompt beam flash allowed the decay of states above the isomer to be found. The longer-lived isomer represents full alignment of the simplest two-particle, one-hole configuration and illuminates the remarkably weak coupling of the proton hole to the $^{210}\mathrm{Pb}$ core.

Details

ISSN :
24699993 and 24699985
Volume :
95
Database :
OpenAIRE
Journal :
Physical Review C
Accession number :
edsair.doi...........a3182f1eb778018103334c3b9bfd06a1