ABSTRACT
A solution of (55)Fe was measured by using liquid scintillation counting (LSC)-TDCR method. The measurement was performed within the frame of the CIPM CCRI(II)-K2.Fe-55 comparison during the year 2006. Two computation codes were used for the calculation of detection efficiency, the difference between the results being analyzed. The photomultipliers asymmetry and its influence on the results, as well as the long-term stability are also analyzed. The influence of the variation of kB value over the activity value is compared with the case of (3)H standardization.
ABSTRACT
The paper summarizes the IFIN-HH triple coincidence liquid scintillation counter used for the implementation of the TDCR method. The electronic unit was recently extended to record the three individual double coincidence ratios to take into account the differences in the quantum efficiencies of the three-photomultiplier tubes. Some details of the electronic system and the data processing are given. The critical point of a TDCR counter is to adjust correctly the discriminator levels on the three channels under the single electron peak. The paper describes the method of adjustment based on the evolution of the dark counting rate versus the discriminator level. Also indicated is the influence of the discrimination level on the activity results as measured at IFIN-HH using a 3H standard. The performances of the IFIN-HH TDCR counter was checked against the measurement results of the TDCR counters of CSIR NML (South Africa), RC (Poland) and LNHB (France). A set of ready-to-measure 63Ni sources in liquid scintillator, in sealed counting vials, was prepared and dispatched for measurement to all these laboratories. The paper describes designs of the TDCR counters used. An analysis and discussion of the measurement results is given.
Subject(s)
Radioisotopes/analysis , Scintillation Counting/instrumentation , Scintillation Counting/methods , Equipment Design , Equipment Failure Analysis , France , Radiation Dosage , Radioisotopes/chemistry , Radioisotopes/standards , Reproducibility of Results , Romania , Scintillation Counting/standards , Sensitivity and SpecificityABSTRACT
The paper presents the results obtained at IFIN-HH during a metrological certification of the commercially available radionuclide calibrator, the CURIEMENTOR2. Its performance was tested for the radionuclides: 57Co, 99mTc, 131I and 137Cs. The calibration factors determined by the manufacturer and those obtained at IFIN-HH differed by less than 3.5%. New calibration factors were determined for 60Co and 188Re, which have, until now, not been distributed by the manufacturer to the users. Furthermore, the linearity of instrument response and the dependence of measuring geometry were checked and found in accordance with the international accepted standards and legal requirements.
