OPERATION HARDIACK I - DATE: TIME: PPG Time 22 July 1958 1620 Juniper GMT 22 duly 1958 0420 Sponsor: SITE: UCRL PPG - Bikini - 4,000 ft from west end cf Tare 11° 29' 165° 22' L6" 15" Site elevation: HEIGHT OF BURST: N £E Sea level 12.11 ft TYPE OF BURST AND PLACEMENT: CLOUD TOP HEIGHT: Surface burst from barge 40,000 ft MSL CLOUD BOTTOM HRIGHT: on water 24,000 ft MSL REMARKS: Only individual island dose rates are available. These were obtained from Radiological Safety organization helicopter surveys at H+ hours. The helicopter survey technique called for the pilot either to land the aircraft at the desired spot, so that a ground reading could be obtained, or to make a slow pass over the desired spot at an elevation of 25 feet. Readings taken at 25 feet were multiplied by a factor of 2 in order to cbtain a reasonab.2 approximation ot the true ground reading. The basic instrument used in the aerial surveys was the AN/PDR-39 survey meter modified to read up to 500 r/hr. The tl"? decay approximation was used to extrapolate the H+ hour dose-rate readings to H+1l hour. 295