Purpose of the flight and payload description
The instrument used for the measurement of the alpha particle flux consisted of a combination of two scintillation counters and a Cerenkov counter as can be seen schematically in the figure at left.
A concidence between counter 1 and counter 3 was required to trigger the apparatus. A simultaneous measurement of the energy loss of the particle in counter 1 and its velocity in the Cerenkov counter 2 was then made, which yielded good discrimination between protons and alpha particles down to 450 Mev/nucleon.
Details of the balloon flight
Balloon launched on: 9/27/1959
Launch site: Joe Foss field, Sioux Falls, South Dakota, US
Balloon manufacturer/size/composition: Zero Pressure Balloon
End of flight (L for landing time, W for last contact, otherwise termination time): 7/18/1959
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): F 12 h 20 m
These measurements were performed in Sioux Falls, South Dakota, where the Enrico Fermi Institute for Nuclear Studies had two sets of equipment ready to launch on short notice after the occurrence of a solar event.