Gamma Rays from the Proton Bombardment ofMg24

Further measurements on the ${\mathrm{Mg}}^{24}(p, \gamma ){\mathrm{Al}}^{25}$ reaction at the 1.66-Mev resonance have revealed a new level in ${\mathrm{Al}}^{25}$ at an excitation energy of 2.739±0.010 Mev. The level decays to the ground state, the second excited state at 0.95 Mev, and the fourth excited state at 1.81 Mev in the intensity ratios (8±6): (63±10): (29±14). This new level should correspond to a resonance at 0.47 Mev in the laboratory system. A careful search for the resonance failed to show it and an upper limit on its value of $\omega \left(\frac{{\Gamma }_p{\Gamma }_{\gamma }}{\Gamma }\right)$ is 0.6×${10}^{-3\mathrm{}}$ ev. Revised gamma-ray branching ratios for the decay of the level corresponding to the 1.66-Mev resonance have been established. The excitation energies of the first and second excited states in ${\mathrm{Al}}^{25}$ have been measured as 0.461±0.004 and 0.949±0.003 Mev, respectively. The $Q$ value for the ${\mathrm{Mg}}^{24}(p, \gamma ){\mathrm{Al}}^{25}$ reaction is found to be 2.287±0.006 Mev. The existence of the previously reported level at 1.61 Mev in ${\mathrm{Al}}^{25}$ is confirmed as is the fact that the proton width of the 0.418-Mev resonance in the ${\mathrm{Mg}}^{24}(p, \gamma )$ reaction is substantially greater than the gamma-ray width.