The Photodisintegration Cross Section of Beryllium at 2.185 Mev

The cross section for the photodisintegration of ${\mathrm{Be}}^9$ at 2.185 Mev has been measured using gamma-rays which follow the beta-decay of ${\mathrm{Pr}}^{144}$. A value of 3.9×${10}^{-28\mathrm{}}$ ${\mathrm{cm}}^2$ was found, in reasonably good agreement with the valence neutron model. This value is lower than the values at 1.81 Mev and 2.50 Mev, in agreement with the theoretical prediction that a minimum value of the cross section should be found near 2.2 Mev.