Observation of cosmic-ray particles with Z>35
Document Type
Article
Publication Date
1-1-1973
Abstract
Tracks of very heavy cosmic-ray particles have been recorded in nuclear emulsions and several different types of plastic detectors exposed during two high-altitude ballon flights in September 1968. Based on a total of 113 tracks, the following flux values have been derived for kinetic energies >1 GeV/nucleon: J(35≤Z≤40)=(16±4)×10-6 J(41≤Z≤50)=(28±6)×10-6 J(51≤Z≤60)=(9±2)×10-6 J(61≤Z≤70)=(1.8±0.7)×10-6 J(71≤Z≤85)=(3±1)×10-6 J(Z86)=(1.0±0.6)×10-6 The well-established presence of particles with Z86 requires a cosmic-ray source in which the r process of nucleosynthesis has been effective. The relative abundances over the charge region (51≤Z≤85) show agreement with solar-system abundances, but there appear to be significant departures for the two lower-charge groups. Calibration of the detectors and experimental problems are also discussed. © 1973 The American Physical Society.
Publication Source (Journal or Book title)
Physical Review D
First Page
1707
Last Page
1722
Recommended Citation
Blanford, G., Friedlander, M., Klarmann, J., Pomeroy, S., Walker, R., Wefel, J., Fowler, P., Kidd, J., Kobetich, E., Moses, R., & Thorne, R. (1973). Observation of cosmic-ray particles with Z>35. Physical Review D, 8 (6), 1707-1722. https://doi.org/10.1103/PhysRevD.8.1707