Measurement of the [sup.90]Sr absolute activity using the autocorrelation single-crystal scintillation method

It is shown for the first time that the ASCSTS technique we have introduced several years ago for lifetime measurements can be also used for measuring low level activities. A good example with practical relevance in this respect is [sup.90]Sr isotope. In order to apply this technique the radioactive isotope must have an isomeric state with a lifetime spanning the ns-[micro]s range. This method is adequate for measuring weak activities with high detection efficiency in a geometry close to 4[pi]. It is experimentally demonstrated that ASCSTS method is a reliable, high efficiency technique for measuring absolute radioactivity in the long radioactive chains. Keywords Radioactive sources * Autocorrelation single-crystal scintillation time spectrometer * Weak radioactivity * Lifetime measurement