The reaction ${\mathrm{Si}}^{28}(p,\gamma ){\mathrm{P}}^{29}$ at the $E_p=5.834\mathrm{}$ MeV resonance was used to populate the ${\mathrm{P}}^{29}$ 8.38-MeV level, thought to be the first ${\mathrm{P}}^{29}$ level with $T=\frac{3}{2}$. A 32-${\mathrm{cm}}^3$ Ge(Li) counter was used to study the $\gamma$ radiations from this state; $\gamma$-ray energies (keV), together with the ${\mathrm{P}}^{29}$ transition assignment (MeV), and branching ratios (%) are: 7000.0 ± 1.8 (8.38 → 1.38), 15.3 ± 1.5; 6430.3 ± 2.6 (8.38 → 1.95), 54.1 ± 2.4; and 5962.3 ± 2.6 (8.38 → 2.42), 30.6 ± 2.0. A search was made for a $\gamma$-ray branch analogous to the 20% branch of the mirror level in ${\mathrm{Si}}^{29}$, 8.31 → 4.90 MeV. The limits on two branches suggested by known ${\mathrm{P}}^{29}$ spin and parity assignments are: 8.38 → 4.97, (25 ± 14)% and 8.38 → 5.30, <3.4% (2 standard deviations). Angular distributions were measured for the 8.38 → 1.38, 8.38 → 1.95, and 8.38 → 2.42 transitions; the analysis of these distributions restricts $J\left(8.38\right)\mathrm{}$ to $\frac{3}{2}$ or $\frac{5}{2}$, and provides $\gamma$-ray multipole-mixing ratios. The radiative decay of this level is compared with the radiative decay of the mirror level in the conjugate nucleus, ${\mathrm{Si}}^{29}$. Incidental measurements were made of the energies of the second and third excited states in ${\mathrm{P}}^{29}$: $E_x \left(\mathrm{keV}\right)=1950.0\mathrm{}\pm 1.3 \mathrm{and} 2421.7\pm 1.3$, respectively. The excitation energy of the $T=\frac{3}{2}$ level was found to be $E_x=8382.1\mathrm{}\pm 2.8$ keV.

• Received 16 December 1971

DOI:https://doi.org/10.1103/PhysRevC.5.1351