Studies of the chemical composition of cosmic rays withZ=3?30 at high and low energies

Results on the Energy Dependence of Cosmic-Ray Charge Composition 1.

“…We have used the Ai franm Webber et al, (1972) to extrapolate the observed flux to the top of the atmosphere. Table 2 gives the integral flux of the different groups of nuclei at the top of the atmosphere.…”

Propagation of cosmic rays in the galaxy

“…It is possible to deduce the source composition from the observed elemental abundances by making use of the available fragmentation cross-sections of cosmic ray nuclei and plausible models of propagation in interstellar space. Many attempts have been made in the past to determine source composition, either for groups of nuclei or for prominent elements using the slab model for the propagation of cosmic rays (Hayakawa et al, 1958;Aizu et al, 1960;Badhwar et al, 1962;Kristiansson, 1966;Beck and Yiou, 1968;Waddington, 1969); more recently it has been carried out by using different propagation models (Shapiro et al, 1970aRamaty and Ligenfelter, 1971;Webber et al, 1972;Casse and Goret, 1973;Cowsik and Wilson, 1973). In all these calculations, the fragmentation cross-sections used are mostly based on semi-empirical relations.…”

“…In Table 4.1, we show the cosmic ray source abundances relative to carbon as calculated by Shapiro et al, (1973), who made use of the Webber et al, 1972;Casse and Goret, 1973). The abundances given in this Table 4.1 assume a power law spectrum in energy per nucleon, but if the spectrum obeys a power law in rigidity, then the value for hy'drogen would be 2 x 104 instead of 5 x 104.…”

A cosmochemical view of cosmic rays and solar particles

“…In the interval from He up to Fe, careful measurements with high-resolution detectors in satellites (Cartwright et al, 1971), in balloons (Webber et al, 1972;Casse et al, 1971;Juliusson et al, 1972;Webber et al, 1973;Smith et al, 1973), and on the lunar surface Chan and Price, 1973) have recently established that the composition of cosmic rays slowly changes with energy. The changes are of two types, as Figure 5 shows: the relative proportion of secondary nuclei such as the elements with 17~Z~<25 ( Figure 5a) and the elements Li, Be and B decrease with increasing energy (Figure 5b).…”

“…A pathlength distribution is regarded as acceptable if rare nuclei covering a very broad charge interval simultaneously disappear. The method has been discussed in detail in Shapiro and Silberberg (1970), by Webber et al (1972), and more recently by Cartwright et al (1973). For the high-Z cosmic rays, which have very short breakup mean free paths, (Shirk et al, 1973) is considerably steeper than the spectra of He, CNO, and Fe and suggests that different sources may be contributing ultra-heavy cosmic rays of low energy.…”