Purpose of the flight and payload description

This flight was part of a series of balloon missions carried out in the Fall of 1963 from Holloman AFB as a cooperative effort between the Air Force Cambridge Research Laboratories and the Istituto Nazionale di Fisica Nucleare, Milan University, from Italy.

The main objective on each flight was to measure the charge spectrum of heavy primaries and their diurnal variation, if any, using a payload developed by Dr. D. Shapiro at the Air Force Cambridge Research Laboratories. No further details of the instrument involved in this part of the mission were found.

By the italian part, the objective was to measure the flux of low neutrons employing a detector based on boron-plastic scintillator counters. At left we can see an image and scheme of the fast neutron detector. It consisted of two boron-plastic scintillator discs, A and B, each fitted in a paraffin block (to slow down the neutrons) and viewed by photomultipliers. Disc A contains boron enriched to 92 % in 10B isotopes while B is of natural boron (4 % 10B). The electronic circuits were lodged between the bases of the two photomultipliers. Twenty-four Ni-Cd cells with a 0.9 ampere-hours capacity were situated around the photomultipliers. These were capable to provide sufficient power for 14 hours of operation.

The whole instrument was encased in a pressure-tight aluminium container and weighed 6 kg.

The Boron plastic scintillators consisted of a plastic containing ZnS and boron plastic, in a ratio 2:1 by weight, pressed on to a 5 cm diameter plexiglass disc, in which were cut concentric grooves 0.9 mm deep, the whole backed by an aluminium disc of 0.5 mm thickness. The photomultipliers used were RCA 6655A, tile voltages applied being adjusted to obtain equal gain on both channels by means of a calibration with NaI crystal - Cs source assembly.

Two detection units were flown in this flight, with different sizes of moderators (1" and 4").

Details of the balloon flight

Balloon launched on: 10/8/1963
Launch site: Holloman Air Force Base, Alamogordo, New Mexico, US  
Balloon launched by: Air Force Cambridge Research Laboratories (AFCRL)
Balloon manufacturer/size/composition: Zero Pressure Balloon 2.690.000 cuft (1.5 mil.)
End of flight (L for landing time, W for last contact, otherwise termination time): 10/9/1963
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 28 h
Landing site: 30 miles NNW of Childress, Texas, US
Payload weight: 651 lbs

External references

Images of the mission

The team of the Milan University preparing the neutron detectors Balloon launch      

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