Consider a collimated beam of 1 MeV photons impinging at a right angle on the surface of a pool of water (density = 1 g/cm3) with an intensity of 2 x 10 9 ?/cm2?s. According to the tables at the NIST website, (µ a/?) = 0.0311 cm2/g and (µ/?) = 0.0706 cm2/g for 1 MeV photons in water.
(a) What is the interaction rate at the surface of the water in interactions/cm3?s?
(b) What is the energy absorption rate at the surface of the water in MeV/cm3?s?
(c) What is the dose rate in rads/s at the surface?
(d) What is the uncollided beam intensity 28.4 cm below the surface? Note, 1 rad = 100 ergs/gram.