A Search for Primary Cosmic Gamma-Radiation. I

A search has been made for primary cosmic gamma-radiation in the energy range 3.4 to 90 Mev. The apparatus was a counter telescope in which ionizing rays were excluded by anticoincidence and $\gamma$-rays detected by their conversion products in lead. The apparatus was carried above the atmosphere in a V-2 rocket launched at White Sands, New Mexico. The recorded $\gamma$-ray counting rate is reduced about a factor of 2 by corrections of various sorts. The variation of detection efficiency with energy permits the results to be stated in terms of the energy crossing unit horizontal area in unit time. The result is 1.4 Mev/${\mathrm{cm}}^2$/sec. This is 1300 times less than the corresponding figure for the total cosmic-ray energy at this latitude. Considering the smallness of the result and the nature of the corrections, it is possible that the result is actually a null one.