Coincidence summing between X-rays and conversion electrons in 137Cs

The probability of coincidence summing between the conversion electrons and the X-rays emitted in the decay of the first excited state of 137Ba was measured in close geometry. It was shown that the probability of the registration of electrons decreases exponentially with the amount of material between the source and the detector. The probability of the registration of a conversion electron emitted in the solid angle subtended by the detector crystal amounts, in the absence of any material between the source and detector, to about 0.6.

► The number of conversion electrons was measured as a function of the thickness of the absorbing layer.
► For the measurement coincidence summing between electrons and gamma-rays from 137Cs was used.
► The probability for detecting the electrons drops off exponentially with the thickness of the layer.