Absorption coefficients in water

The first term in the bracket is the contribution from the primary gamma rays (1.17 and 1.33 Mev.) at the point P, r cm. from the point source and the last term is the contribution from the scattered gamma rays at the point P. d is the dose rate in rads per sec. r is the distance in water from the point isotropic 60Co source of C curies fit = 0.0632 cm."1 is the total linear absorption coefficient in water for 1.25 Mev. photons ... 

---