The scintillation properties of crystalline Ba${\mathrm{F}}_2$ have been investigated. It was found that this substance yields a reasonably well-defined photopeak when exposed to gamma rays from ${\mathrm{Na}}^{22}$. With DuMont K1306 and 6292 photomultipliers, the signals from Ba${\mathrm{F}}_2$ are about $\frac{1}{5}$ to $\frac{1}{10}$ as strong as those from NaI(Tl). With a Ba${\mathrm{F}}_2$ crystal as a target, the excitation function for the ${\mathrm{F}}^{19}(n, \alpha ){\mathrm{N}}^{16}$ reaction was observed in the region from an apparent threshold near 3.2 Mev up to $E_n=6\mathrm{}$ Mev. Several new resonances were found in this region. The cross section generally increases with increasing neutron energy, rising from 85 mb at 4.48 Mev to 200 mb near 6 Mev. Absolute accuracy of cross-section measurements was ±15%.

• Received 10 August 1959

DOI:https://doi.org/10.1103/PhysRev.117.514