Degradation of Gamma Rays in Water

The spectra of degraded gamma rays from ${\mathrm{Co}}^{60}$ and ${\mathrm{Hg}}^{203}$ have been examined with a scintillation spectrometer, as a function of distance from the source, in an infinite water medium. The energy region below 0.150 Mev corresponding to multiple scattering was studied in greatest detail. Both the attenuation and the spectrum shape showed good agreement with the theoretical predictions of Spencer and Fano.