Multiple Scattering of Fast Protons in Photographic Emulsions

Abstract

Measurements have been made of the multiple Coulomb scattering of protons with energies of 337±1 Mev and 218±2 Mev in Ilford G-5 emulsions. A total of 261 tracks with a combined length of 130.4 cm were analyzed by the determination of the lateral multiple scattering deflections according to the "coordinate method." The results are summarized in terms of the customary scattering factors which, for a given cell length, indicate the proportionality of the average multiple scattering deflection to the quantity "charge/momentum×velocity" of the scattered particle. Scattering factors are given for cell lengths of 250, 500, 750, and 1000 microns. These results are compared with the predictions of various theories of multiple scattering, including those of Moliere, Snyder, and Scott, as well as a proposed extension of the theory of Goudsmit and Saunderson, which has the advantage of being directly and conveniently applicable to the analysis of lateral multiple scattering deflections. The predicted theoretical scattering factors in fair agreement with the experimental values, but slightly larger; the discrepancies are either within, or just outside of, the limits of the experimental error (3-6 percent).