Purpose of the flight and payload description
The objective of the flight was to obtain measurements of proton and helium low-energy spectra (100-260 Mev) present in cosmic rays at stratospheric altitudes. The flight was part of a yearly program carried out at high and intermediate latitudes by the Department of Physics and Astronomy of the University of Maryland.
The detector consisted of a Geiger-tube hodoscope, a dE/dx scintillator, and a sandwich of lead and plastic scintillator plates, which constitute a total energy calorimeter. The term hodoscope is derived from the Greek roots hodos, meaning path, and scopes, meaning to watch. Thus the term hodoscope is used in particle physics to describe any device (usually electronic) that determines and displays the trajectory of a charged particle.
An schematic diagram of the hodoscope identifying its major components and indicating some triggering trajectories can be seen in the figure at left (click to enlarge). The hodoscope, made up of five pairs of crossed trays of Geiger tubes,defined the range and geometry of particles incident on the apparatus and detected nuclear interactions occurring in the lead. The dE/dx scintillator measured the rate of ionization loss of the incident particle. The combined light output of the five calorimeter plates was a sample of the total energy deposited in the lead absorber.
The amplitudes of the dE/dx and calorimeter signals were determined by independent logarithmic pulse-height analyzers, whose channel width was 33% (8 channels cover a factor of 10) and whose dynamic range was a factor of 100 in pulse height. The trays of 1.58-cm diameter Geiger tubes measured 15 by 15 cm, and the apparatus was 32 cm high. The absorber thickness was equivalent to 75 gm/cm2 of lead. The scintillation pulse heights and Geiger-tube discharges were processed in the flight apparatus, telemetered to a ground station and tape recorded for post-flight analysis by computer.
Details of the balloon flight
Balloon launched on: 7/23/1968 at 20:07 utc
Launch site: Fort Churchill Airport, Manitoba, Canada
Balloon launched by: Raven Industries Inc.
Balloon manufacturer/size/composition: Zero Pressure Balloon
Flight identification number: Raven Nº 1244
End of flight (L for landing time, W for last contact, otherwise termination time): 7/24/1968 at 13:21 utc
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 18 h