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

A (64)Cu 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 4pibeta liquid scintillation spectrometry with (3)H-standard efficiency tracing. Relatively short (64)Cu 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 (64)Zn(d,2p) (64)Cu reaction. Significant efforts were made to identify and quantify the impurities of (61)Cu and (65)Zn in the mother solution, which were activated through the (64)Zn(d,alphan) (61)Cu and (64)Zn(d,p) (65)Zn reactions, respectively. To this purpose, a new procedure for the determination of pure beta-emitter impurities by the CIEMAT/NIST method has been applied. A transfer standard portable well-type ionisation chamber was also calibrated with minimum uncertainty.