Measurements have been made of the yields and angular distributions of deuterons resulting from the bombardment of ${\mathrm{B}}^{10}$ by 14-Mev neutrons. The spectrum of charged reaction products was measured by means of a coincidence-telescope spectrometer consisting of two proportional counters and a thin NaI scintillator. The telescope was rotated to obtain measurements at various angles. Deuterons corresponding to the ground state and 2.43-Mev excited state of ${\mathrm{Be}}^9$ were identified by measurements of both their energy and $\frac{\mathrm{dE}}{\mathrm{dx}}$ values. The ground-state angular distribution was found to match the expected Butler inverse-stripping curve for $l_p=1\mathrm{}$. The Butler analysis for the excited-state deuterons also gave $l_p=1\mathrm{}$, corresponding to odd parity and spin $\frac{3}{2}$, $\frac{5}{2}$, $\frac{7}{2}$, or $\frac{9}{2}$ for the first excited state of ${\mathrm{Be}}^9$. In particular, the spin value 1/2, to be expected from the $L-S$ coupling model, is excluded. The cross sections, integrated from zero to 90 degrees (center of mass), are 21±3 and 16±2 millibarns, respectively, for the ground- and excited-state reactions.

• Received 1 February 1954

DOI:https://doi.org/10.1103/PhysRev.94.934