Abstract
We employ the Monte Carlo particle collision code DPMJET3.04 to determine the multiplicity spectra of various secondary particles (in addition to pi(0,s)) with gamma's as the final decay state, that are produced in cosmic-ray (p's and a's) interactions with the interstellar medium. We derive an easy-to-use gamma-ray production matrix for cosmic rays with energies up to about 10 PeV. This gamma-ray production matrix is applied to the GeV excess in diffuse Galactic gamma-rays observed by EGRET, and we conclude the non-pi(0) decay components are insufficient to explain the GeV excess, although they have contributed a different spectrum from the pi(0)-decay component. We also test the hypothesis that the TeV-band gamma-ray emission of the shell-type SNR RX J1713.7-3946 observed with HESS is caused by hadronic cosmic rays which are accelerated by a cosmic-ray modified shock. By the chi(2') statistics, we find a continuously softening spectrum is strongly preferred, in contrast to expectations. A hardening spectrum has about 1% probability to explain the HESS data, but then only if a hard cutoff at 50-100 TeV is imposed on the particle spectrum.
