The isotopic composition of galactic cosmic ray lithium, beryllium and boronThe isotopic composition of galactic-cosmic-ray Li, Be, and B has been measured near 100 MeV/nucleon by using the University of Chicago IMP 7 and IMP 8 cosmic-ray telescopes during 1973-1975. The measured abundances allow detailed checks of models of interstellar propagation and solar modulation to be made and conclusions to be drawn concerning the spectral forms at the source and the minimum solar modulation level. For example, comparing these results with local interstellar spectra calculated by using a 'leaky box' model, it is found that if solar modulation is ignored, there is no unique leakage mean free path consistent with all the observations. However, by taking account of a sizable level of residual solar modulation, excellent agreement is obtained between the calculated and measured abundances. Thus, these isotopic abundances confirm the old hypothesis that cosmic-ray Li, Be, and B are produced as secondaries in interstellar space.
Document ID
19790053315
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Garcia-Munoz, M. (Chicago Univ. Chicago, IL, United States)
Mason, G. M. (Chicago Univ. Chicago, IL, United States)
Simpson, J. A. (Chicago, University Chicago, Ill., United States)