Standardisation and precise determination of the half-life of 44Sc

The half-life of the positron-emitter 44Sc has been determined by following the decay rate with two measurement systems; an Ionisation Chamber and a HPGe detector. The combination of seven results gives a value of T1/2=4.042 (25) h, about 2% higher than the recommended value of T1/2=3.97 (4) h (Browne, 2011) and with a lower uncertainty. This radionuclide has also been standardised by coincidence counting, and liquid scintillation counting techniques. A 44Ti/44Sc generator developed at CIEMAT was used to obtain the 44Sc solutions used in all measurements.