1. A monodirectional beam of 500-kilo electronvolt x-rays having an intensity of 10' x-rays/cm2 - sec is incident on an iron slab 20 cm thick. Calculate: 1. the exposure rate in the absence of the iron 2. the uncollided flux 3. the buildup flux 4. the exposure rate behind the slab(a) Here To= 103 x-ray cm2 /sec. ie Io gives an exposure rate Implhr at 500 kev. in the absence of ison, exposure, rate is given by XO = 107 = 10 mR/hr 103 107) 10 RIh8. (b) uncollided flux, Pu = Xoexp (- Mt ) where " M = 0:65 20m so pre= (co MR (hx ) - (0 . 652 4/ (20 (ng) ) = 21.7 8 / cm2 . see. (C ) build up flax, where Bm= 17-u. B = 17.4 x 21.78 (cm). see 2 377 - 58 91 / Cm 2- sec. (d) Expression rate behind the slab is X = 4 B = 377-58 8 (Cm2- sec 18 x-raycm? / see 0. 37:758 MR/ ho