Neutrons from the Proton Bombardment ofP31

The reaction ${\mathrm{P}}^{31}(p, n){\mathrm{S}}^{31}$ has been studied at $E_p=17.2\mathrm{}$ Mev. The energy spectrum of the neutrons was determined by means of proton recoil measurements in nuclear emulsions. The mass excess, $M-A$, of ${\mathrm{S}}^{31}$ was calculated to be -10.04±0.20 Mev. Excited states of ${\mathrm{S}}^{31}$ have been located at 1.15±0.15, 2.28±0.20, 3.35±0.20, 4.51±0.15, 5.94±0.30, and 6.41±0.20 Mev.