Results: Dose rates in the mushroom portion of the cloud were exactly as predicted. Dose rates in the stem of the cloud below the mushroom were a factor of ten below predicted dose rates in the cloud at the times of penetration, The highest dose rate was recorded by the aircraft which penetrated at an altitude of 50,000 feet at A,] minutes. The average dose rate in the cloud which this aircraft experienced was about 150 R/Hr. The time in the cloud was about 3 minutes, giving a dose of 7.5 to the pilot while in the cloud and 1.3 R on the return flight. The contamination factor on the airplane was computed to be 0.5 per cent/minute in the cloud. The total dose recorded by a Rad-Safe film badge was 7590 mr. The duration of the penetration made at 45,000 feet was two minutes and 50 seconds. It began at # 38 minutes. The average dose rate in the cloud was about 75 R/Hr, yielding a total dose in the cloud of about 3 R. The contamination factor on the aircraft was computed to be 0.6% /minute in the cloud. This corresponded to a come home dose of about 0.5 R. The total dose recorded by a Rad-Safe film badge was 2230 mr. The dosages received by the two aircraft which penetrated at 35,000 feet and 40,000 feet were quite low. 260 mr respectively. The total mission dose was 150 and These aircraft were in the radiation field of the cloud for from 60 to 180 seconds. oy Again on this shot, as on the RR cemoxe and the DELETED. it was noted that the dose rate was lower in the stem of the cloud than in the mushroom by a factor of at least ten. The pilots reported none to slight turbulence in the cloud, COPIED/ DOE vat Qn 4 - Saeee The only Ma O