Production of Protons by High Energy<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>γ</mml:mi></mml:math>-Rays

Abstract

The protons ejected from various nuclei by the gamma-ray beam of the 320-Mev Berkeley synchroton have been studied with a proportional counter telescope system. The energy distribution of the protons from carbon, copper, and lead from 7 Mev to 70 Mev at 90\ifmmode^\circ\else\textdegree\fi{} was roughly proportional to $\frac{1}{{E}^{2}}$. The angular distribution was spherically symmetrical for 10-Mev protons and showed a pronounced forward maximum for protons of about 40 Mev. The cross section per nucleus for the ejection of 40-Mev protons was found to be proportional to $Z$.The experimental results indicate that protons above 30 Mev arise primarily from the interaction of the $\ensuremath{\gamma}$-ray with some small subunit of the nucleus rather than through the formation of an excited compound nucleus.