@conference{
author = "Sarap, Nataša and Dejković, Stefana and Janković, Marija and Krneta Nikolić, Jelena and Stanić, Vojislav and Rajačić, Milica",
year = "2023",
abstract = "In the Radiation and Environmental Protection Department, Vinča Institute of Nuclear Sciences, the validated radiochemical analytical method for 90Sr determination in environmental samples is used. The Laboratory for Radiation Measurements within mentioned Department is accredited according to ISO/IEC 17025. The activity of 90Sr is determined indirectly, by beta counting of its daughter product 90Y, and after established radioactive equilibrium during 18 days from the moment of 90Y radiochemical separation. Beta spectrometry by gas flow proportional counter Thermo Eberline FHT 770T is used for detection of 90Sr activity in investigated samples. In order to assure the reliability of the measurement results in accordance with Standard ISO/IEC 17025:2017, quality assurance and quality control (QA/QC) corresponding procedures need to be applied. For this purpose, activities ought to be planned in a systematic manner as described in the quality control documentation. The efficiency calibration of the detection system needs to be performed in a proper manner. The calibration of the detector for beta counting is performed using the Sr-90 certified radioactive standard point source (9031-OL-335/11, produced by Czech Metrology Institute) which is traceable to Bureau International des Poids et Mesures (BIPM). As lowlevel measurements require strict QA/QC requests, the accuracy and reproducibility of measurement systems must be verified periodically. A regular internal quality control of the gas flow proportional counter is performed once a week. Quality control activities include the background measurement and checking of efficiency using adequate radioactive standard source. The measurement values are recorded and verified if they are within the acceptance limits. The obtained results together with acceptance limits during the period of 3 months are graphically presented in control charts. The acceptance limits are set to be ±2σ and ±3σ in relation to the calculated mean value and standard deviation. The results of QC verification within ±2σ are considered to be satisfactory, those within ±3σ are warning, while those that exceeding ±3σ indicate that there is a problem with the measurement system. Consequently, the analysis of causes and design, as well as the application of corrective measures is needed.",
publisher = "Belgrade : Institute of Technical Sciences of SASA",
journal = "21st Young Researchers' Conference Materials Sciences and Engineering : program and the book of abstracts",
title = "Quality control of gas flow proportional counter for beta spectrometric determination of 90Sr",
pages = "25-25",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12308"
}
