Lone experiment with sheep, using sr20~y99 plaques, showed that 2500 reps at the plaques’ surface produced ulceration in one but not another of two sheep.* On the other hand, 1000 rads delivered to tissue depth of 7 ng/em” from a P= one inch diameter disk (type of animal not stated) produced tanning, prolonged erythema and desquanation, **/ It is to be remembered that the above discussion was first based on surface gamma dose rates whereas the monitors will be making their gamma measurements at a height of three feet. Past field experience has indicated that the gamma reading from ionization-type survey meters at ground level is about 50% higher than at three feet. Therefore if it be assumed that a ground level gamma reading of a survey meter is equivalent to a surface dose rate, the ratio of beta dose rate at 7 ng/cm* to gamma dose rate at threefeet is about 200 to 1. ‘Another approach to estimating the ratio of beta dose rate at V7 mg/en® to gamma dose rate at three feet is as follows. Assuming a uniform distribution of 1.0 megacurie per square mile of gamma activ~ ity, the dose rate reading from an infinite field is about 4.1 roent~ Calculations given in appendix B indicate that a like gens/hr.*** concentration of fallout material will produce about 430 reps/hour at 7 ng/en”. This suggests a beta to gamma ratio of about 100 to 1 which is about a factor of two lower than the first approach. Added support to this latter method of estimating beta doses is found in appendix C. Such considerations may be fraught with pitfalls. For example, the above discussion implies a uniform distribution of fallout *"Comparative Study of Experimentally Produced Beta Lesions and Skin Lesions in Utah Range Sheep", Hale, D. B. **HW-33068. Lushbaugh, C. E., Spalding, J. F., and LASL, November 30, 1953. A status report. (UNCLASSIFIED) September 15, 1954. ***Effects of Atomic Weapons. 195u - 18 « (CONFIDENTIAL) :