https://hal-cea.archives-ouvertes.fr/cea-01799862Kossert, KarstenKarstenKossertPTB - Physikalisch-Technische Bundesanstalt [Braunschweig]Marganiec-Galazka, JustynaJustynaMarganiec-GalazkaPTB - Physikalisch-Technische Bundesanstalt [Braunschweig]Mougeot, XavierXavierMougeotLNHB - Laboratoire National Henri Becquerel - DM2I - Département Métrologie Instrumentation & Information - LIST (CEA) - Laboratoire d'Intégration des Systèmes et des Technologies - DRT (CEA) - Direction de Recherche Technologique (CEA) - CEA - Commissariat à l'énergie atomique et aux énergies alternatives - Université Paris-SaclayNaehle, Ole J.Ole J.NaehlePTB - Physikalisch-Technische Bundesanstalt [Braunschweig]Activity determination of 60Co and the importance of its beta spectrumHAL CCSD2018Beta spectrumCIEMAT/NIST efficiency tracingTDCR$^{60}$CoActivity standardizationCoincidence counting[PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex]Le Roy, LénaRadionuclide beta spectra metrology - MetroBeta - JRP EMPIR 15SIB10 - INCOMING - 2020-02-11 10:37:152022-02-17 10:08:032020-02-11 11:58:20enJournal articleshttps://hal-cea.archives-ouvertes.fr/cea-01799862/document10.1016/j.apradiso.2017.06.015application/pdf1The activity concentration of a $^{60}$Co solution was measured by means of two 4$\pi\beta$-$\gamma$ coincidence counting systems using a liquid scintillation counter and a proportional counter (PC) in the beta channel, respectively. Additional liquid scintillation measurements were carried out and CIEMAT/NIST efficiency tracing as well as the triple-to double coincidence ratio (TDCR) methods were applied to analyse the data. The last two methods require computed beta spectra to determine the counting efficiencies. The results of both 4$\pi\beta$-$\gamma$ coincidence counting techniques are in very good agreement and yield a robust reference value. The initial activity concentration determined with liquid scintillation counting was found to be significantly lower than the results from 4$\pi\beta$-$\gamma$ a coincidence counting. In addition, the results from TDCR and CIEMAT/NIST show some inconsistency. The discrepancies were resolved by applying new beta spectrum calculations for the dominant allowed beta transition of $^{60}$Co. The use of calculations which take screening effects as well as the atomic exchange effect into account leads to good agreement between all four methods; the combination of these techniques delivers an important validation of beta spectra.