Energy spectra at 90° in the laboratory were obtained for He, Li, Be, and B fragments from a uranium target irradiated with 4.9 GeV protons and 2.1 GeV/nucleon deuterons and $\alpha$ particles. Data at 25 and 155° were also obtained with the proton and $\alpha$ particle beams. In comparing the incident deuteron data with the incident proton data, it was found that the cross sections were a factor of 1.5 higher but the shapes of the energy spectra were unchanged. However, with incident $\alpha$ particles it was found that the cross sections were a factor of 3 to 4 larger, and the energy spectra were somewhat broadened indicating that the effective Coulomb barriers are 15% lower, and the apparent temperatures 1.5 MeV higher. It is concluded that in the $\alpha$ particle irradiations the deposition energies are larger than with either incident protons or incident deuterons.

NUCLEAR REACTIONS $\mathrm{U}(p, x)$, $E=4.9\mathrm{}$ GeV; $\mathrm{U}(\alpha , x)$, $E=2.1\mathrm{}$ GeV/nucleon; ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, ${}_{}{}^6{}_{}{}^{}\mathrm{He}$, ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ measured $E_x$ at 90°, $\sigma \left(\theta \right)$, $\sigma$; ${}_{}{}^8{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^9{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^{11}{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{Be}$ estimated $\sigma$. $\mathrm{U}(d, x)$, $E=2.1\mathrm{}$ GeV/nucleon; ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ measured $E_x$ at 90°, estimated $\sigma$; ${}_{}{}^6{}_{}{}^{}\mathrm{He}$, ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^8{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^9{}_{}{}^{}\mathrm{Li}$ estimated $\sigma$.

• Received 9 December 1974

DOI:https://doi.org/10.1103/PhysRevC.11.1280