Pon monitors. If two or three aircraft and aoproximately one dozen traired personnel are devoted solely to radiation monitoring duties it would be possible to delineate the general fall-out area adequately. A complete fall-out map could be prepared from the air readings where the contamination is given in relative units. Then all that is required is a few ground readings to change the relative readings of the fall-out are map to gamea roentgen dose values. If this suggestion is accepted, it should be kept in mind that air readings should not be utilized to deter- baal mine the contamination of such small areas ag ground zero etc., since it is futile to attempt to pin point the cortamination of a given small area from an airplane, <dxperience also indicates that although the conductive ity meter used in an airplane is very sensitive to contamination in the air, the normal radiological gamma indicating instruments (MX-5 and T13) are relatively insensitive to such contamination. If conductivity meters are used, the serial survey must be made 24 hours after shot tine to be sure that the air is cleared of all radioactive fall-out (within 200 miles of ground zero). If MX-5 or TI1B instruments are used the aerial survey could start two or three bcurs after shot time. The flight pattern will be governed by the radex plot to keep the airplane out of the path of the fall-out. Historically “here is oaly one incident in Which the MX=-5 or T1B instruments carried in the aircraft became contaminated during T/S or U/K Test Operations. This occurred during T/S, Fox Shot (see Reference #1) and is indicated in Mgure 2 of this report. During the first shot of U/K (Annie) the radex plot showed a very narrow path of fall-out, and it was indisated that the aircraft could De 1-3 of cms Suu GLay ~~ UNCLASSIFIED pal 2owe. |