Pomiary 60Co w obiektach z żelazną matrycą

Radioactive cobalt isotope 60Co is produced in neutron activation process of stable isotope 59Co by neutron capture reaction 59Co(n,g)60Co, in solar wind charge exchange 60Ni(n,p)60Co or in spallation process 62Ni(n,p2n)60Co. These processes are responsible for isotope 60Co production either in nuclear reactor on Earth or beyond – in stars and in meteorites (induced by cosmic rays). In this work the results of 60Co measurements in metal sources by gamma spectrometry laboratory are presented. A metal reference radioactive standards made up of steel cast with discs shaped geometries and different diameters have been tested in gamma-ray spectrometry measurement system. The reference activity concentrations of 60Co were in the range of (0.291±0.010) Bq·g–1 to (1.544±0.030) Bq·g–1. The mean minimal detectable activities (MDA) obtained by series of the 6 to 18 hours lasting measurements of described above standards with HPGe detectors carried out in NCBJ OR POLATOM were in the range of 6.1 mBq·g–1 to 8.5 mBq·g–1. The results correspond to the values of 60Co activity concentration measured in the iron meteorites with young terrestrial ages.