Standardization of 75Se and X-ray emission probability data

A 75Se solution has been standardized by combining the 4π(KX + e)—γ-coincidence measurements at two different γ-ray window settings. The component to the total uncertainty that originated from the correction associated with the metastable level was estimated to be 0.1%. The 4πKX—γ-coincidence method with zero registration of low-energy conversion electrons was also used. The measured activity has been used to determine the 75Se KX-ray emission probability with the aid of a calibrated Si(Li) spectrometer.