Precise measurements of projectile charge changing cross sections for intermediate energy heavy ions

Ota, Shuya*; Yasuda, Nakahiro*; Sihver, L.*; Kodaira, Satoshi*; Ideguchi, Yusuke*; Hasebe, Nobuyuki*

Projectile charge-changing cross sections for nuclei in galactic cosmic rays (GCRs) on hydrogen play essentially important roles for the study of origin and source composition of GCRs. Previous experimental and theoretical works done so far made much progress on those cross sections. However, there are still uncertainties in much of the cross section data, and therefore the present knowledge of cross sections has not led to successful determination of the GCR source composition. To improve the uncertainties, a novel measurement system of projectile charge-changing cross section using CR-39 plastic nuclear track detectors with excellent position and nuclear charge resolutions has been developed. We carried out measurements of total and partial charge-changing cross sections for Fe and Mg on and targets at 0.1 to 1 GeV/n using the method.