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. (1990) The ^(54)Mn Clock and Its Implications for Cosmic Ray Propagation and Fe Isotope Studies. In: Proceedings of the 21st International Cosmic Ray Conference. Vol.3. Department of Physics and Mathematical Physics, The University of Adelaide , Northfield, South Australia, pp. 397-400.

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 B-decay halflife 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 (<l GeV/nuc) ^(54)Mn produced by Fe fragmentation had decayed. Using a propagation code that includes improved fragmentation cross-sections, and data from HEA0-3 and other spacecraft, we have re-examined the evidence for ^(54)Mn decay. We conclude that present cosmic ray data cannot distinguish the possibility of ^(54)Mn decay in cosmic rays, 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:Book Section
Related URLs:
URLURL TypeDescription
Mewaldt, R. A.0000-0003-2178-9111
Additional Information:© Organizing Committee of the 21st Int. Cosmic Ray Conference. Provided by the NASA Astrophysics Data System. This work was supported in part by NASA under grants NAG8-618 and NCR 05-002-160. We appreciate the assistance of T. L. Garrard.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
NASANCR 05-002-160
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory1989-22
Record Number:CaltechAUTHORS:20140714-161626711
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:47197
Deposited By: Deborah Miles
Deposited On:22 Jul 2014 20:21
Last Modified:22 Nov 2019 09:58

Repository Staff Only: item control page