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Elemental technetium and promethium as cosmic-ray clocksThe possibility of using elemental Tc (Z = 43) and Pm (Z = 61) as clocks to measure the mean cosmic-ray confinement time in the Galaxy, tau(epsilon) is considered. For this purpose it is necessary to estimate the unknown beta(+) decay half-lives of several Tc and Pm isotopes; these estimates are obtained using beta-decay systematics. In the case of Tc it is possible to estimate the half-lives sufficiently well and show that this element can indeed be used as a cosmic-ray clock; in the case of Pm the half-lives are too uncertain to permit any conclusion. In order to make meaningful measurement of tau(epsilon) using elemental Tc, a comsic-ray detector must have a charge resolution less than about 0.25e in the region around Tc, and enough collecting power to detect a few hundred Tc nuclei.
Document ID
19870062574
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Drach, J.
(California Univ. Berkeley, CA, United States)
Salamon, M. H.
(California, University Berkeley, United States)
Date Acquired
August 13, 2013
Publication Date
August 1, 1987
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 319
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
87A49848
Funding Number(s)
CONTRACT_GRANT: NAS1-17806
Distribution Limits
Public
Copyright
Other

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