Photoprotons Produced by 245±15-Mev Gamma Rays on Carbon

Abstract

A carbon target was bombarded by 342-Mev bremsstrahlung from the Berkeley synchrotron. The energy spectrum of protons produced at 60 deg was measured from 90-250 Mev. Interactions due to 245±15 Mev gamma rays were selected out by requiring a coincidence between the protons from the target and the electrons associated with these gamma rays. Analysis was made using the quasi-deuteron model of Levinger. In contrast with previous analyses of this kind, conservation of both momentum and energy were taken into account in a fairly accurate way. Results of this analysis determine the momentum distribution of the centers of mass of the quasi-deuterons. The momentum distribution that results in the observed proton spectrum, normalized to one quasi-deuteron, is given by $\frac{d^{3}N}{d{P_D}^3}=\frac{0.2}{{\left(4\mathrm{}\pi M{E}_1\right)}^{\frac{3}{2}}}\exp \left(-\frac{{P_D}^2}{4M{E}_1}\right)+\frac{0.8}{{\left(4\mathrm{}\pi M{E}_2\right)}^{\frac{3}{2}}}\exp \left(-\frac{{P_D}^2}{4M{E}_2}\right),$ where $E_1=1.6\mathrm{}$ Mev, $E_2=20\mathrm{}$ Mev.