Comparison of the performance of the Quantulus GCT 6220 and the Quantulus 1220 for the determination of 55Fe and 63Ni

An experimental study of the response of the newer Quantulus GTC 6220 liquid scintillation spectrometer has been conducted with the objective of determining the performance of this counter for the determination of 55 Fe and 63 Ni in the environment. Its response has been compared to that of the well-established Quantulus 1220. For this, Guard Compensation Technology (GCT) was used to reduce the Lower Limit of Detection (LLD in what follows). Two scintillation cocktails, Hidex ProSafe HC+ and Revvity OptiPhase HiSafe 3 were compared in this work. The parameters employed for this assessment were background count rate, counting efficiency, and LLD. • An alternative to the older, now out of maintenance Quantulus 1220, should be found to carry out research on the environmental radioactive impact of nuclear fuel cycle activities. • The newer Quantulus GCT 6220 liquid scintillation spectrometer has proven to be a competitive system for determining low levels of 55 Fe and 63 Ni if GCT technology is used. • The REACH-compliant scintillation cocktail Hidex ProSafe HC+ wast proved to be a suitable scintillator when GCT is used.