_ A self-recording dose rate instrument is also installed in the aircraft which is equipped with timing markers to show cloud entry and exit. It aut- omatically starts recording when the radiation field reaches l-r/hr. The aircraft were equipped also with Bendix dosimeters, NBS film packs and film badges to indicate total dose received on the mission. The contamination studies consisted of surveying the aircraft with both gamma and beta survey instruments for the purpose of obtaining the general contamination level on and in the immediate vicinity of the air- craft. Based on these data individual film were placed at selected points on the aircraft. instrument survey. The exposure time for the films is determined from the These exposures give an autograph of the particle dis- tribution, the general background and a measure of the beta dose from the particulate material. Comparing these values with the gamma survey isone of the methods for determining the S/fratios. In addition film stacks are exposed to the aircraft to permit a study of the energy distribution of the beta spectrum and to determine thef/Uratio. Results The dose rates in the cloud and total dose received on the mission were = to or less than the predicted values. The pilot of the aircraft which penetrated at 449 minutes received a total dose of 3.3R as measured by a Rad—Safe film badge, The maximm dose rate in the cloud was about 300R/Hr with the average dose rate being about 120R/Hr. The "Contamina- tion Factor" on the aircraft was computed to be ,75%/min in the cloud. The pilot of the aircraft penetrating at £58 minutes received a total dose of 3.06R as measured by a Rad-Safe film badge. the cloud was about lOOR/Hr. The average rate in The "Contamination Factor" on the aircraft was 1,52%/Minute. Pleb/pogg LANL Re The third aircraft planned to penetrate at 50M ft at 465 minutes. - 25- wee. | 4 \