“…Elemental and isotopic abundances of spallogenic noble gases in iron meteorites have been the subject of many investigations since PANETH et al (1952) first reported the presence of spallogenic 'He in meteorites. Measurements of spallogenic He, Ne and Ar in iron meteorites (EBERT and WANKE, 1957;VINOGRADOV et al, 1957;NIER, 1958, 1959;FIRE MAN, 1958;GERLING and LEVSKII, 1958;NIER, 1960, 1962;SCHAEFFER and ZAHRIN GER, 1960;SCHAEFFER and FISHER, 1960;HEY MANN et al, 1966;NYQUIST et al, 1967NYQUIST et al, , 1972NYQUIST et al, , 1973HINTENBERGER et al, 1969;SCHULTZ et al, , 1971 are combined with measure ments of cosmic-ray produced radioactivities in iron meteorites (ARNOLD et al, 1961;LIPSCHTz et al, 1965;SCHAEFFER and HEYMANN, 1965) to obtain information about the length of time that bodies were exposed to cosmic rays, the pre atmospheric size. of the meteoroids, the energy spectrum of cosmic ray primaries and the at tenuation of primary and secondary cosmic ray particles in matter.…”