The cosmic gamma-ray spectrum between 0.3 and 27 MeV measured on Apollo 15.

Results of new measurements of the total cosmic gamma-ray spectrum in the 0.3- to 27-MeV range obtained on Apollo 15. These data were obtained with an isotropic scintillation counter similar to that used on Ranger 3 and ERS-18. The new high-precision data permit extension and clarification of the spectrum above 1 MeV, where recent balloon and earth-satellite observations have caused doubts as to the validity of the ERS-18 data.