OPERATION HARDTACK I - TATE: TIME: PPG Time Walnut CMT Sponsor: 15 Jun 1958 1h Jun 1958 0630 1830 SITE: LASL PPG - Eniwetok - 5,000 ft OW of Janet 11° 39' 162° 13’ 37" 31" Site elevation: HEIGHT OF BURST: N & Sea level 7.21 ft TYPE OF BURST AND PLACEMENT: Surface burst from barge CLOUD TOP HEIGHT: 61,000 #t MSL CLOUD BOTTOM HEIGHT: NM on water REMARKS: Only individual island dose rates are available. These were obtained from Radiological Safety organization helicopter 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 cc:ld 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 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 t7°* decay approximation was used to extrapolate the H+4 hour dose-rate readings to H+l hour. 250