eat neasuremente at a height of three fest. ( Fast field experiences has indicated that the gamma reading from ionisation-typs survey meters at ground level is about 50% higher than at three feet. Therefore if it be assumed that a ground leve] gamma reading of a survey uster is equivalert te a surface dose rate, the ratio ef beta dose rate at 7 mg/em” to gamma dose rate at Shree is about 200 tw i. Another approach te estinating the ratio of beta dose rate at 7 ng/en* to gamma ose rate at three fect is as follows. Ascuming a wmifore distri- bution of 1.0 megacurie per square eile of gamma activity, the dose rete reading from an infinite field is about 4.1 roentgens/hour." Caleulations given in appendix 3 indicate that e« like eoncemtration ef fallout material will produce ebout 430 reps/hour at 7 ag/ont?. This suggests a beta te gums ratio of about 100 te 1 whieh is about « factor ef two lover than the first approach. added support to this latter method of estinating beta doses is found in appendix C. Suah considerations may be franght with pitfalls. Por exemple, the above discussion implies a unifore distribution ef ratersWvrtal. viously, thie is not correct but how far this deviates froe the facts and to what extent this influences the results 1s difficult to assess, indicate that the production of recognisable beta burns particle requires a high specifle aetivity. Calculations from a single (See Policy III fer disoussion.) It nay/be,however, that the partieles of fallout are close encugh te have overlapping of radiation flelds and thus require signifieantly apecifie activity of the particles to produce beta burns. *"Effects of Atomia Weapens", 19506 lower This hypothesis