Bias in the measurement of radon gas using ionization chambers: Application to SIR.

Two main non-destructive techniques can be used to measure standard Rn gas ampoules: well-type ionization chambers and gamma-ray spectrometry, the former being used in the Système International de Référence (SIR) for international comparison purposes. The reliability of these techniques requires that the variability of the flame-sealed gas glass ampoules used have a negligible influence on the detector response. This variability is studied in this work by considering three parameters: the volume of the ampoule, the position of the sealing point and the thickness of the glass.

Comparison of I activity measurements at the NCBJ RC POLATOM and the ENEA-INMRI linked to the BIPM SIR system.

A bilateral comparison between ENEA-INMRI (Italy) and NCBJ RC POLATOM (Poland) of I-solution activity measurements was organized in the year 2015 and piloted by POLATOM, which provided the sources for the comparison. The I master solution was standardized independently at both institutes by using Liquid Scintillation Counting and ionization chamber techniques. The I master solution was then sent by POLATOM to the BIPM International Reference System (SIR).

Consultative committee on ionizing radiation: Impact on radionuclide metrology.

In response to the CIPM MRA, and to improve radioactivity measurements in the face of advancing technologies, the CIPM's consultative committee on ionizing radiation developed a strategic approach to the realization and validation of measurement traceability for radionuclide metrology. As a consequence, measurement institutions throughout the world have devoted no small effort to establish radionuclide metrology capabilities, supported by active quality management systems and validated through prioritized participation in international comparisons, providing a varied stakeholder community with measurement confidence.

Standardization, decay data measurements and evaluation of 64Cu.

The purposes of this study were to create national activity standards of (64)Cu, to make possible the definition of an international key comparison reference value and to determine the decay data in order to improve the decay scheme. Four laboratories measured the activity of a (64)Cu solution; these results were compared through the International Reference System. Moreover, the laboratories carried out new measurements of the photon emission intensities and of the half-life.

Comparison of triple-to-double coincidence ratio (TDCR) efficiency calculations and uncertainty assessments for 99Tc.

A comparison exercise for data analysis was recently conducted by the Liquid Scintillation Counting Working Group (LSCWG) of the International Committee on Radionuclide Metrology (ICRM) to evaluate the uncertainties involved in applying different analysis methodologies (including computer programs) for the triple-to-double coincidence ratio (TDCR) method. The goals of the comparison were to (1) study differences in calculation results from different TDCR analysis programs, (2) investigate differences in analysis techniques and uncertainty assessment philosophies between laboratories, and (3) study the effect of not taking asymmetry of photomultiplier tube (PMT) efficiencies into account on the calculated activity. To achieve this, a single set of TDCR data for the pure beta emitter (99)Tc, was distributed to the participants, who analyzed the data according to their normal procedures and report the activity concentration of the (99)Tc solution from their results.