Simple method for absolute activity measurement of 60Co source

The activity of 60Co source was measured using the full absorption, sum and random coincidence (pile-up) peaks and the total spectrum area. It is shown that if the true and random coincidences in the single detector are treated correctly, no additional data are needed for absolute source strength measurement. With the source on the detector end-cap (when the angular correlation effects are negligible), this simple method yields absolute activity values deviating from the reference activity by about 1%.