The scintillation counter probe encloses a NaI crystal of 13 inches diameter and 13 inches in length, and a Dumont photo multiplier tube in a steel pipes 7.8 centimeters in diameter, The probe was con- nected to a count rate meter by a very long cable on a reel, and used to take readings at varying depths below the surface, During the voyage from Japan, gamma background for the scintillation counter was reported to us as 2400 cpm. We were advised that 500 <pm was equivalent to 0.7 milliroentgens per week. During the survey of the TAKUYO on 26 July, a rough check was made to compare the background readings of the Japanese scintillation couter with our MX=-5. The following results indicate a reasonable check: Scintillation counter; MX-5: 3315 cpm gamma (equivalent to 0.03 mr/hr) 0,045 mr/hr ganma The equipment on the SATUMA MARU consistea of one laboratory type geiger counter similar to that on the TAKUYO, and one 0-200 millirocentgen self-reading dosimeter and charger. The dosimeter was of Japanese manu- facture and similar to our Keleket 0-200 milliroentgen dosimeter. During the voyage of the SATUMA, the dosimeter hung in a plastic bag filled with a dessicant in a bulkhead doorway to the "Scientific Observation Room", The door reméined open at all times and the dosimeter was therefore in an exposed position. Readings taken daily by the scientific personnel aboard are shown in Tab A, Appendix IV, The readings show the doses of 26 milliroentgens from 8 to 15 July, and 24 milliroentgens from 15 July to 19 July. There was no air sampling equipment aboard either ship. The wnits for the air data (cpm per cubic meter) listed on the ships course plots DOE ARCIYVE3 47