40 i +— 80 38 75 70 po Ty 30 (A,O-4O0msshr ater (A .40-80mr/h er MR/HOUR 65 ~= ~ ° + 25 20 15 ~—+ 55 | 10 / i. oe | oO —Te| 2 4 6 8 | 10 7 Lo | 12 a . + 450 { wie | ee t i | ‘ { 14 16 (6 20 22 J 24 28 40 MICROAMPERES Figure 2.2 Mark I calibration from distant point source of radium, Site Elmer Rad~Safe compound, 10 May 1954. Microammeter: Weston 301, 0~20ua. experimental field reading of Mark II the calibration curves given in Figure 2.3, but only after these latter values have.been multiplied by a factor of 1.5; that is, after ordinates of the solid curves of Figure 2.3 have been displaced upward by multiplying them by the factor of 1.5. The Mark It instrument calibrated in this manner has been used as a standard for absolute intensity of radiation underwater throughout the cruise; all other instruments used during the trip have been in effect calibrated against the Mark II response. 2.1.3 Measurements Made. About 1,000 radiation measurements were made in the survey following Shot 5. The majority of these measurements were from the Mark I, I, 20