Activity standardization and decay data of 64Cu.

The activity of a solution of (64)Cu was measured by 4pibeta(PC)-gamma coincidence counting and liquid scintillation counting using the CIEMAT/NIST method. In addition, 4pi ionization chambers were used to establish and preserve calibration factors for secondary standardizations and for a determination of the half-life, for which a value of 12.704(5)h was measured. The photon emission probabilities were determined using gamma-ray spectrometry, finding values of p(511 keV)=0.3512(22) and p(1346 keV)=0.00474(5). The results were checked for consistency, and an ampoule was submitted to the BIPM to have the activity result entered into the database of the International Reference System (SIR), yielding the first entry for this radionuclide.