Purpose of the flight and payload description
The objective of the flight was to observe gamma rays in the cosmic radiation from 30 to 500 MeV using a spark chamber. The flight was a cooperative effort between the Case Institute of Technology from Cleveland, Ohio and the Space Sciences Laboratory of the University of California in Berkeley.
In the image at left can be seen an scheme of the geometry of the spark chamber and triggering counters.
The spark-chamber system was designed to have an energy threshold well below the peak in the 77° decay spectrum at 67.5 MeV. An electron-positron pair created in the chamber within the acceptance cone of counters 2 and 3 would trigger the chamber. Counter 1 was an anticoincidence shield. The minimum energy of 30 MeV was determined by the thickness of the absorber above counter 3. The maximum energy at which a pair originating in the center of the chamber would give two resolvable tracks was ~ 500 MeV.
The instantaneous orientation of the chamber for each event in celestial coordinates was monitored by photographing a pair of levels and a magnetometer on the same 16-mm frame which recorded the two stereoscopic views of the chamber.
Details of the balloon flight
Balloon launched on: 2/6/1964 at 6:49 cst
Launch site: Columbia Scientific Balloon Facility, Palestine, Texas, US
Balloon launched by: National Center for Atmospheric Research (NCAR)
Balloon manufacturer/size/composition: Zero Pressure Balloon Raven - 3.000.000 cuft (0.5 MIL.)
Balloon serial number: 2333-531-8201 Serial Nº 175
Flight identification number: 31P
End of flight (L for landing time, W for last contact, otherwise termination time): 2/6/1964
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): F 9 h 30 m
Landing site: 5 miles NNW of Roanoke, Alabama, US
Payload weight: 325 lbs