Development of a primary standard for calibration of 64Cu activity measurement systems

A 64Cu national primary standard, was developed by the National Institute for Ionising Radiation Metrology (INMRI) of the ENEA (ENEA-INMRI) using the CIEMAT/NIST method of 4πβ liquid scintillation spectrometry with 3H-standard efficiency tracing. Relatively short 64Cu half-life is required for the work to be performed at the production site. It was produced at the Scanditronix MC40 Cyclotron of the Joint Research Centre (JRC) of the European Commission (Ispra, Italy) through the 64Zn(d,2p) 64Cu reaction. Significant efforts were made to identify and quantify the impurities of 61Cu and 65Zn in the mother solution, which were activated through the 64Zn(d,αn) 61Cu and 64Zn(d,p) 65Zn reactions, respectively. To this purpose, a new procedure for the determination of pure β-emitter impurities by the CIEMAT/NIST method has been applied. A transfer standard portable well-type ionisation chamber was also calibrated with minimum uncertainty.