which was extremely prevalent following Mike detonation. Major repair problems did not arise because instrumentu were provided in excess. Inoperative instruments were deadlined and returned to the United States for major repairs. Alpha-radiation-detection instruments whose probes had been sealed against humidity leaks were adequate for thia operation. 6.2 PHOTODOSIMETRY AND RECORDS SECTION The responsibilities of this section were to 1. Issuc, receive, process, and interpret all photographic film badges. 2. Issue, receive, read, and record all Task Group 132.1 (TG 132.1) personnel dosimeters. 3. Maintain records of exposures which will be available to proper authorities. 4. Forward photodosimetry reports to the appropriate service surgeon or civilian laboratory at the comnletion of the operation. §. Forward processed 1ilm to AFSWPforfinal storage at the completion of the operation. A record of exposures will accompany this shipment. 8. Forward all film records to the Division of Biology and Medicine, AEC. 6.2.1 Operational Activities Except for minor changes the procedures of photodosimetry were followed according to the operating procedure given in Appendix D. This procedure proved of great value in orlenting all personnel and is suggested as a guide in the standardization of future test photodosimetry operations. Difficulties were experienced because of lack of space and a shortage of clerical help. Owing to difficulties of mixing, the use of Ansco developer did not prove as satisfactory as Kodak developer and fixer. An all-weather calibration site was sorely needed for long-period calibration exposures; use of an empty warehouse is not a reliable expedient. 6.2.2 Summary of Exposures No serious overexposure of Task Force personnel was encountered, although several incidents of exposures exceeding the Task Force limit did occur. Nineteen personnel of TG 132.4 participated in the flights of the C-54 and the SA-16 aircraft into the material falling from the Mike cloud within 1 to 2 hr after detonation. The SA-16 aircraft was engaged in search and rescue operations for which tolerance limits had been waived. The C-54 aircraft was engaged in photographic operations at altitudes which appeared to be less than 2000 ft and at times less than 1'4 hr after detonation. This maneuver violated preshot instructions to fly the photographic mission at 5000 ft no earlier than 2 hr after detonation. The film-badge readings for these personnel varied from a low of 8.6 to a high of 17.8 r. Two personnel of TG 132.1 exceeded the Task Force tolerance limit of 3.9 r during continued recovary cperations following King shot. Both were minor in nature and less than 4.1 r. No overexpogures occurred within TG 132.2 or TG 132.3. A total of 5000 film badges were utilized and processed during Operation Ivy. 6.3 RADIOCHEMICAL SECTION, LABORATORY GROUP The mobile Radiological Field Laboratory, AN/MDQ-1(XE-3), designed by the Nucleonics Branch, Signa) Corps Engineering Laboratories (SCEL), was assigned to the Rad-Safe group during Operation lvy to participate in its health-physics program. The mission of the laboratory was tc obtain information on the radiation hazards existing in airborne material, Mquids, and solids to supplement the gamma-fiux measurements obtainable by area surveys. The samples received were assayed to determine the intensity of alpha, beta, and 30 - + ce ge ee ee ee wee ee