Fast Protons from 270-Mevn−dCollisions

Abstract

The differential cross section for production of high energy protons in $n-d$ scattering, using the 270-Mev neutron beam of the 184-in. cyclotron, has been measured at scattering angles between 4° and 58°. For normalization, yields of protons from $n-p$ scattering were measured at each scattering angle. In all cases, only protons above a cut-off energy of 200 Mev ${cos}^2\Theta$ were accepted by the counter system. In addition, through the use of a magnetic analyzer, energy distributions of the $n-d$ protons were measured at 4° and 22.5°. The energy distributions closely resembled, in shape, the energy distributions of $n-p$ protons at the same angles, confirming the similarity in nature between collisions of high energy neutrons with free protons and collisions with protons bound in deuterium. Total yield of protons above the cut-off energy is lower for $n-d$ than for $n-p$ collisions, however, the ratio of the two being about 0.7 at all angles observed. Effects of the exclusion principle, of the internal momentum distribution of the deuteron, and of the difference in average potential energy between the dineutron and the deuteron are discussed as possible causes of the lowering of the $n-d$ proton yield below that from $n-p$ scattering.