Relative High Energy Neutron Yields from Targets Bombarded with Protons and Deuterons

Relative neutron yields in the forward direction from various target elements bombarded with 340-Mev protons and 190-Mev deuterons have been measured. Bismuth fission chambers with a threshold of about 50 Mev were used to detect the high energy neutrons. When a deuteron beam is used, the neutron yields for light elements agree with the values predicted by the deuteron stripping theory. For the heavy elements, the observed values are fitted best by adding a function proportional to $Z^2$ to the stripping theory values. This can be interpreted as evidence for the production of high energy neutrons by the electric field disintegration of the deuteron. The neutron yields from the proton beam vary approximately as ${\mathrm{}(A-Z)\mathrm{}}^{\frac{2}{3}}$ for target elements from carbon to uranium. This indicates that the heavy elements are not completely transparent to 340-Mev protons. Beryllium has an anomalous neutron yield 50 percent higher than that for carbon.