Letter to the Editor
Evidence from Voyager and ISEE-3 spacecraft
Data for the decay of secondary K-electron capture isotopes during the propagation of cosmic rays in the Galaxy
A. Soutoul 1,
R. Legrain 1,
A. Lukasiak 2,
F.B. McDonald 2 and
W.R. Webber 3
Received 31 July 1997 / Accepted 12 May 1998
New data from the cosmic ray experiment on the Voyager spacecraft confirms and extends earlier data from a similar experiment on the ISEE-3 spacecraft which indicates the possibility of the decay of certain K-capture isotopes during the interstellar propagation of galactic cosmic rays. These cosmic ray measurements, along with the cross section measurements, indicate that 25% of the K-capture isotopes 51Cr and 49V produced as secondaries have decayed at interstellar energy of 400 MeV/nuc. This suggests a possible interstellar energy gain 100 MeV/nuc out of the current interstellar energy 500 MeV/nuc. This measurement suggests that the study of the K-capture isotopes may now have reached a level that will soon provide definitive information on the amount of re-acceleration that may occur during cosmic-ray propagation after an initial acceleration in the cosmic ray sources.
Key words: ISM: cosmic rays
This article contains no SIMBAD objects.
© European Southern Observatory (ESO) 1998
Online publication: July 27, 1998