‘’ 15,000 feet and reported cloud radiation intensities about half those usually expected for this time, He was directed to make repeated penetrations through this small upper portion of the cloud until he received his assigned dosage, This was accomplished in 8 passes averaging about 35 seconds each, Red Two was then directed into the middle and thicker piece of cloud at 10,000 feet and reported radiation intensities about double those of the upper portion. White One and Two were then directed into the lower portion of the cloud at 5,000 feet and reported usual radiation intensities although the cloud was thin enough so that the aircraft were visible to Cassidy flying above them throughout their sampling penetrations, Hotshot was held until 30 minutes after Red Two had left the middle portion of the cloud and then directed in at 10,00 feet, He reported average cloud radiation intensities down by a factor of at least five from those reported by Red Two in the same portion of the cloud, NUMBER RATIOS The number of fissions measured in the samples by radio-chemistry at Los Alamos averaged about 30% of the number predicted at PPG from observati of radiation levels of the sample papers after they were removed from the aircraft. DELETED. Anis discrepancy is believed to be due to a muck larger than usual proportion of short-lived activities such as chlorine and sodium in the cloud which tend to buildup pilot dosages without giving the usual proportion of activity remaining on the filter papers when they arriv at Los Alamos, Pilot radiation exposure from aircraft background during return to base was somewhat higher than normal on the middle and lower F-8|, but normal for the highest aircraft, Red One, and the latest aircraft, Hots COPIED LANL Root ~ 33 - a ‘