Spectrum determination and modification of the AFRL Co-60 cell

The spectrum of a Co-60 facility includes more than the two photopeaks of gamma ray emission. If there is a large low energy contribution from scattering, dose enhancement might be a problem. It is important to know the spectrum of a Co-60 facility and understand how experimental modifications can change that spectrum. The AFRL Co-60 cell spectrum is found to be a clean spectrum with small low energy contributions and dominant Co-60 photopeaks. Experimental modifications to reduce dose enhancement such as the use of a Pb/Al box and even better a Pb/Sn/Cu/Al box are found to decrease the low energy contributions. Experimental modifications to reduce dose rate such as using lead attenuators in front of the experiment and/or raising the source partially are found to significantly alter the spectrum, sometimes creating large low energy contributions