tation did not record for a sufficiently long time to determine definitively the half life of this isotope. Reliability of Residual-Radiation Data. In general, the residual instrumentation functioned either well or not at all. Tables 3.1 through 3.4 show that the major malfunctions were due to inoperative chart drives. The possibility of malfunc2 10 T T TAT . T Y NX, jer Z T I Fr qT r T | 4 4 ~ pm 4 ho & c N ® \ oO x OF 2 C NoN — \ a © <L |}.-+ E - ‘\ E o © q KY tJ Oo 7 \ ~ ' | i OD 2 N ‘\ ee zB i i ~~ ® & < r wa. _ 0.1 10 1 1 4 \—- 7 ! i Ny t pot i 10° 4 piped ' 10° l | i 1o* Time After Shots , Minutes Figure 3.1 Residual exposure rate within blast shield versus time for Shot Zuni; Station 221.05, range 68,6C0 feet. 72.9-hour exposure, 502r. For unshielded rate multiply by 1.4. Total tioning of the recorders was anticipated prior to the operation; however, lack of funds and time torced the use of these recorders. The recorders thet worked were checked with a Timemaster and adjusted to within + 0.069 percent accuracy. The repcated calibrations cf the instrument systems indicated a maximumtotal error of less than 10 percent. Figures 3.1, 3.3, 3.7, 3.8, 3.9, 3.13, 3.14, 3.15, 3.16, 3.17, and 3.18 present data taken with the detector heads inside a steel pipe which served as blast and thermal protection. The results from these stations should be increased by a factor of about 1.4 to compensate for the shielding of the blast housings. This estimate of the shielding 29 Text continued on Page 43.

Select target paragraph3