A Caltech Library Service

The ^(54)Mn Clock and Its Implications for Cosmic Ray Propagation and Fe Isotope Studies

Grove, J. E. and Hayes, B. T. and Mewaldt, R. A. and Webber, W. R. (1991) The ^(54)Mn Clock and Its Implications for Cosmic Ray Propagation and Fe Isotope Studies. Astrophysical Journal, 377 (2). pp. 680-684. ISSN 0004-637X. doi:10.1086/170395.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


Radioactive ^(54)Mn suggested as a 'clock' for measuring the lifetime of heavy cosmic rays, has a poorly known β-decay half-life estimated to be in the range from ~10^5 to 10 ^7 yr. Some years ago Koch et al. concluded from measurements of the Mn/Fe ratio that a significant fraction of low-energy (<1 GeV/nucleon) ^(54)Mn produced by Fe fragmentation had decayed. Using a propagation code that includes improved fragmentation cross-sections, and recent data from HEAO 3 and a number of other spacecraft, we have reexamined the evidence for ^(54)Mn decay in cosmic rays. We conclude that present cosmic-ray data cannot establish the degree of ^(54)Mn decay, but point out that this question has important implications for studies of the ^(54)Fe abundance in cosmic-ray source material, as well as for cosmic-ray propagation studies.

Item Type:Article
Related URLs:
URLURL TypeDescription
Mewaldt, R. A.0000-0003-2178-9111
Additional Information:Copyright 1991 American Astronomical Society. Received 1990 August 27; accepted 1991 February 20. This work was supported in part by NASA under grants NAG8-678, NAG5-722, and NAGW-1919. We appreciate the assistance of T. L. Garrard with the propagation calculations. Some of this work was performed while B. T. Hayes was the recipient of a Caltech Summer Undergraduate Research Fellowship (SURF).
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Summer Undergraduate Research Fellowship (SURF), CaltechUNSPECIFIED
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory1990-15
Issue or Number:2
Record Number:CaltechAUTHORS:20140509-084205965
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:45629
Deposited By: Deborah Miles
Deposited On:09 May 2014 19:48
Last Modified:10 Nov 2021 17:14

Repository Staff Only: item control page