3.5 OPERATION TUMBLER-SNAPPER (U) Greration Tumbler-Snapper was conducted at the NTS during April, May, and June 1952. The operation consisted of four airdrops and four tower shots. The pertinent shot information is presented in Table 3.27, and the meteorological data at shot time are presented in Table 2.28. (U) The gamma measurements were made by two groups: 30) and SCEL (Reference 31). LASL (Reference LASL used film in the AW holder,mounted on cthich Pt WF) angle-iron stakes; SCEL used film in the N35 holder attacred to aluminum stakes. Neither group mentions azimuth or fallout effects -- except for nacper III -- when the cloud passed over the LASL line. It was assumed hat the films were placed upwind of the otner snots where fallout had ittle effect. However, the LASL results are consistently higher than he SCEL results, and possibly the LASL films recorded some fallout radiaion. Shot 1 was not instrumented for gamma measurements. (U) The neutron data for Shots 3, 4, and 8 were taken from measurements made by the Naval Research Lab (NRL) (References 32 z-d 14). The LASL obtained neutron data at Shots 4, 5, 6, 7, 8, which «re recurded in Reference 33. Reference 13 records neutron-flux data for all eight shots during this operation. (U) The SCEL gamma data for Shots 2 thru 8 are presented in Tables 3.29 thru 3.35 with their appropriate correction factors. Tables 3.36 thru 3.42 give the LASL film data without neutron corrections. 3.22 thru 3.28 present the squared versus slant-range. 3.6 Pigures corrected SCEL gamma-dose-times-slant-range- OPERATION IVY (U) Operation Ivy, held at the PPG during October and November 1952, consisted of two large-yield shots: airdrop. Mike, a surface shot, and King, an Shot information and meteorological data are given in Tables 3.43 and 3.44, resvectively. (U) Gamma measurements were made by LASL on both shots with film (Reference 34). The film types used are the same as syecified for Cyueration Tumoler-Snapper. To obtain initial gamma data in the heavy-fallout field expected from iMike, a film-drop gadget »as used whereby films exposed to radiation for a predetermined time would automatically drop below ground ° level into a radistion-protected area. Unfortunately these gadgets did not work, and many were filied with water, sand, and debris. The few 31