fo cnaneh FrPES ee Road blocks were established en Highways 93 and 91 following shots numbers seven and nine of Upshot-Knothole. The highest reading on a private automobile was 100 mr/hr (gamma) inside and 110 mr/hr outside at H plus 33 hours, monitored), About 75 cars were washed (rougtly 1/8 of the total All of the cars that were washed except the one meniticned above, had outside dose rate reacings less than half of the kignhest, The ratio of dose rate readings on the outside of the car to inside varied from unity to about 4/1. Probably one of the important factors here is the difference between driving with windows and/or ventilators opened or closed. One bus read 250 ur/hr outside and average of 1CO mr/br inside with a high inside reading over the rear seat of 140 mr/hr at EH plus § 3/4 hours. Considering the azount of time one normally spends in an automolile, these dose rates do not necessarily represent a health hazard in terms of gatsa doses, What is probably a more limiting factor is the direct con= especizlly when changing 04 . tae tamination ome might acquire by rubbing against the outside cf the cer, a tire. it is assumed that monitoring will be accomplished outside a gcnerzl ERENTremit.reer eeeeg 5 a TREQ Me radiation field. Theoretical calculations (appendix D) indicate that gaicoa dose rate readirgs taken at fowr inckesfroma surface will be 512, 42%, and 27% of those by a meter at three feet above an equally contaminated infinite field when the radii of contamination are respectively 3 feet, 2 feet, and 1 foot. These data suggest that when the gamma dose rate reading at four inches from a generally contaminated car is about one half that for an infinite plane taken at three feet, the degree of contamination per unit area will be about equal; and when the wheels are being monitored 1/2 to 1/4 of a cor te vrene ; t