On the Photodisintegration of Beryllium and Deuterium

High voltage x-rays have been used to redetermine the thresholds for the photodisintegration of beryllium and deuterium nuclei, giving 1.627\ifmmode\pm\else\textpm\fi{}0.010 Mv and 2.183\ifmmode\pm\else\textpm\fi{}0.012 Mv, respectively. The ratio of the two cross sections ($\frac{{\ensuremath{\sigma}}_{\mathrm{Be}}}{{\ensuremath{\sigma}}_{\mathrm{D}}}$) at 15 kv above the threshold voltage is approximately 10. The angular distribution of the neutrons from the photodisintegration of deuterium has been investigated, with x-rays of 2.43 Mev maximum energy, and found to be approximately isotropic. On the basis of these data, the value of the ratio of the photomagnetic to photoelectric cross section is estimated to be 6 to 1.