Operation Hardtack Preliminary Report. Project 2.7, Nuclear Radiation From a Detonation at Very-High Altitude.
NAVAL RESEARCH LAB WASHINGTON DC
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The objective was to measure the neutron spectrum and total prompt gamma ray flux produced by the detonation of a nuclear device of low yield approximately 2 kt at an altitude of about 90,000 feet. This information was to be obtained by suitable detectors In the vicinity of the nuclear device and telemetered to the ground to be recorded and subsequently analyzed. The theory and instrumentation for measurement of neutron spectrum and total prompt gamma ray flux from a nuclear device detonated at an altitude of 85,000 feet is described. Measurement of neutron time of flight with a Li6I scintillator-photodiode detector, with a similar Li6I detector for gamma-ray correction of the Li6I detector, was planned. Tile measurement was to have extended to plus 120 msec. A CsI scintillation detector, whose output was integrated for the first 10 microsec after the zero time, and a KBr crystal, whose darkening was measured as a function of time for 120 msec after zero time, were to be used to detect gamma flux. Tile detector outputs were to have been electronically encoded and recorded on a magnetic tape recorder programmed to record for 120 msec after zero time, reduce its speed to 116 of the recording speed, and continuously play back the data. The recorder output modulated a 70-kc voltage controlled oscillator used in a standard frequency modulated telemetering system. A ground station received and recorded the signal. The Bendix command system shared by this project and Projects 1.10 and 8.2 failed, and no data was obtained.
- Nuclear Weapons