A Photographic Spark Chamber for Manned Satellites

The advent of manned space flight for extended periods will allow the retrieval of important photographic data. Under construction is a gamma ray spark chamber with photographic recording which is a prototype for manned satellite applications. On a 14-day orbital flight it can detect a point source of ¿-rays of intensity 10-7 photons cm-2 sec-1 and can determine the power law dependence of the energy spectrum for a 10-6 source. The ¿-ray energy can be measured from 2.5¿107 to 5¿109 ev. The counter triggering arrangement will have a 3¿ anticoincidence shield plus a directional Cerenkov detector to minimize accidental triggerings of the chamber. A high altitude balloon flight of this system in Panama is scheduled for October, 1965. Two smaller spark chambers, designed to detect cosmic ray gamma rays and electrons, have been flown on a series of 15 flights from 120,000 to 140,000 ft. over the past two years.