Energy spectra and angular distributions have been measured for high-energy gamma rays ($E_{\gamma }$>40 MeV) from the heavy-ion reaction ${}_{}{}^{136}{}_{}{}^{}$Xe+Sn at bombarding energies of E/A=89 and 124 MeV. Gamma rays are observed with energies up to 160 MeV, and the energy spectra are roughly exponential above 40 MeV. The angular distributions of the gamma rays are forward peaked in the laboratory frame and are consistent with emission from a source moving with a velocity equal to the nucleon-nucleon center-of-mass velocity. The angular distributions show no significant anisotropy in the nucleon-nucleon frame. The production cross sections agree with systematics observed for lighter systems.

• Received 3 April 1989

DOI:https://doi.org/10.1103/PhysRevC.40.1207