Angular Distribution of Photoprotons from Deuterium from 9 to 23 Mev

Photoprotons from a deuterated paraffin target irradiated with betatron x-rays have been detected with a NaI(Tl) scintillator. The angle and energy of the protons have been measured, and the data has been fitted to the angular distribution form $f\left(\theta \right)=(A+B{sin}^2\theta )(1+2\mathrm{}\beta cos\theta )$. The ratio $\frac{A}{B}$ rises from a value of 0.015±0.041 for the 9- to 12-Mev photon group to a value of 0.133±0.020 for the 20- to 23-Mev group. $\frac{A}{B}$ increases in a complicated way suggesting several contributions to the isotropic component. The value determined for $\beta$ agrees with the calculation of $\frac{v_p}{c}$. A Schiff thin-target spectrum is assumed for the incident photons, and the cross section obtained is consistent with the Marshall and Guth calculations, although the energy dependence of the data has slightly less slope than the calculated values.