Nuclear interactions of 950 MeV protons

Ilford G5 emulsions have been exposed to the 950 MeV beam of the Birmingham proton synchrotron. A mean free path for nuclear interaction of 37·0 ± 2·3 cm was obtained. The disintegrations were separated into those occurring in the light (carbon, nitrogen and oxygen) and heavy (silver and bromine) nuclei of the emulsions, and the mean cross-sections for star production were estimated to be 200 ± 50 and 1100 ± 120 mb, respectively. The results have been used to calculate the value of the constant r0 in the expression for the nuclear radius R = r0A½ and a value of 1·30 ± 0·05 × 10-13 cm was obtained. The possible effects of meson production are discussed; it is shown that the results are consistent with the assumption of a probability for meson production of approximately 0·6 per star.