OPERATION HARDTACK IPPG Time 13 May 1955 0630 TOTAL YIELD: Time to Ond maximum: Radius at 2nd maximum: Diameter: Depth: Lip: SITE: LASL PPG - Eniwetok - West end of Gene 12° 4o't 30" N 1620 12' 20" 8 Site elevation: Sea level 1.37 Mt FIREBALL DATA: Time to lst minimum: CRATER DATA: Sponsor: GMT 12 May 1958 1830 100 msec 0.94 to 1.35 sec 3,641 ft 4,000 ft 171 ft HEIGHT OF BURST: 3 ft TYPE OF BURST AND PLACEMENT: Surface burst from 10 ft deep tank of water sitting on coral soil CLOUD TOP HEIGHT: T2,eCO ft MSL CLOUD BOTTOM HEIGHT: NM Apparently washed away REMARKS: Only individual island dose rates are available. These were cbtained from Radiological Safety organization helicopter surveys at H+ hours. The heliccpter survey technique called for the pilot either to land une aircraft at the desired spot, so that a sround 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 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-1-2 decay approximation was used to extrapolate the H+4 hour dose rate readings to H+l1 hour. 201 — DATE: TIME: Koa