OPERATION HARDTACK I - DATE: TIME: PPG Time Olive GMT 23 July 1998 Sponsor: 22 July 1956 0830 2030 SITE: UCRL PPG - Eniwetok - SW of Janet, 4,000 ft from the nearest edge of island (Sta. 1312) 11° 39' 48" N 162° 13' 48" &£ Site elevation: HEIGHT OF BURST: CLOUD TOP HEIGHT: 50,000 ft MSL CLOUD BOTTOM HEIGHT: Sea level 6.0 ft TYPE OF BURST AND PLACEMENT: 16,000 ft MSL Surface burst on water from barge REMARKS: Only individual dose rates are available. These were obtained from Radiological Safety orgnization nelicopter surveys at H+4 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 reet. Readings taken at 25 feet were multiplied by a factor of 2 in order to obtain a reasonable approximation of 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 t-!*® decay approximation was used to extrapolate the H+ hour dose-rate readings to H+l hour. 299