tation did not record for a sufficiently long time to determine definitively the half life of this isotope. Reliability of Residual-Radiation Data. i general, the residual in- strumentation 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;- Tv T T T = N . o tT T roy tT 4 » 4 a 2 2 rT L £ a / | + T 7 io —_ @ ‘N oN 4 __ 2 - uJ o pf a E Ee | 4-. C po r non | ry L 10 to 1 |i ~ fi 4 4 \ by | | 10° \ Ny 4 4 —t || 0.1 pt a pe 4 -_ ' mo 4 ‘A t BS thf 2 @ 4 L : oO o A _LN } ' i tt : 10° 1 pia 10 Time After Shots , Minutes Figure 3.1 Residval exposure rate within blast shield versus time for Shot Zuni; Station 221.05, range 68,600 feet. For unshielded rate multiply by 1.4. Total 72.9-hour exposure, 502r. tioning of the recorders was anticipated prior to the opeation; however, lack of funds and time torced the use of these recorders. The recorders thet worked were checked with a Timemastcr and adjusted tu withn 40.069 pei: cnt accuracy. The repcated calibrations cf the instrument systems indicated a maximum total 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 28 Text continued on Page 43.