Chapter 2 OPERATIONS and INSTRUMENTATION The instrumentation canisters and nuclear device were suspended from a large plastic balloon, launched at 1125:05, 28 April 1968, from the flight deck of the USS Boxer (CVS-21). Detonation occurred at 1440, 28 April 1958 at 85,000 feet at Latitude 12 degrees 37 minutes north and Longitude 163 degrees 01.5 minutes east, in the Eniwetok Proving Grounds. Command signals for operation of the equipment when floating altitude had been reached, as well as telemetering receiving and recording facilities, were provided by Project 1.10's “ground” station on the flight deck of the USS Boxer. Project 2.7 instrumentation was contained in a pressurized aluminum vessel, 22 inches high and 8'/ inches in diameter, comprising the upper half of the Canister 5. The detectors were mounted in the top of the half canister, with the more massive components in the bottom. The lower half of Canister 6 and the other four canisters contained instrumentation used by Projecta 8.2 and 1.10. Control and telemetering for Project 2.7 were accomplished by equipment mounted in the lower half of Canister 5, serving both Projects 2.7 and 1.10. At the time of detonation, Canister 5 waa 2,750 feet from the nuclear device, or at an altitude of about 82,280 feet. A ttme~of-flight neutron measurement was selected. Two scintillation detectors were used, one with a Li'l crystal and one with a normal Lil crystal. The Lil and Lil crystals should respond to gamma rays in the same way. tron component can be isolated. Two gamma-ray detectors were employed. By comparison of their outputs, the neu- The first used a Cal oryatal ag a scintil- lator, the second, a KBr crystal in which the darkening produced by gamma radiation was measured. The Cal detector channel was deaigned to measure the integral of the gamma radiation during the period from 0 to 10 nsec after detonation. The KBr detectoris in- herently an integrating device and would provide, at any time after detonation, the inte- gral of the gamma radiation from 0 to ¢. In the low-density air at 90,000 feet, it wag believed that the five canisters might hang in a straight line, since there would probably be little wind shear in the 3,000 feet between the nuclear device and Canister 5. This would interpose the mass of the upper four can- isters between the device and the detectors used by Project 2.7, introducing an unknown attenuation. To avoid this, Canister § was equipped with a small rocket (PET, manufactured by Atlantic Research Corporation, Alexandria, Virginia) producing 40 pounds of thrust for 1 second. This was to have been detonated at minus 2 seconds to produce a 0.8-g acceleration of the 80-poundogniuter.. The resulting deflection of the canister would have been approximately 30 feet at zero time and continued to about 90 feet at plus 7 seconds. The outputs of the four detectora were encoded electronically and recorded simultaneously on four parallel tracks of a magnetic-tape recorder having a recording time of about 120 msec. On completion of the recording operation, the tape speed was reduced to ‘4, of the recording speed and the data played out, one channel at a time, Into a standard Bendix 70-kc voltage-controlled oscillator and frequency-modulated transmitter lo14