Sunil K. Singh, Liji Shaiju, Aashna Gupta, S. M. Tripathi, V. Sathian, Probal Chaudhury
{"title":"Estimation of Reference Gamma Radiation Field for Calibration of Radiation Monitors","authors":"Sunil K. Singh, Liji Shaiju, Aashna Gupta, S. M. Tripathi, V. Sathian, Probal Chaudhury","doi":"10.1007/s12647-023-00699-x","DOIUrl":null,"url":null,"abstract":"<div><p>Laboratories/facilities dealing with ionizing radiation encounter radiation field which are measured using suitable gamma radiation monitors, for area and personal monitoring. These radiation monitors are subjected to periodic calibrations to confirm that they are still fit for the purpose. In India, periodic calibration of these radiation monitors is carried out by NABL accredited calibration laboratories using source exposure devices containing radionuclide sources of <sup>137</sup>Cs and/or <sup>60</sup>Co. Calibration laboratories get the output from these source exposure devices standardized by RSSD, BARC, Mumbai. RSSD, BARC, provides a report on the measured output, in the form of air kerma rates at different distances, which is traceable to relevant national standards. The laboratory then uses the standardized radiation field in day-to-day calibration, by taking air kerma rate mostly at distance of 100 cm (fixed distance) as reference for estimating radiation fields at other distances by using inverse square law. The air kerma rate values obtained by the using inverse square law shows deviation from the measured values with an allowed deviation up to 5%. The impact of this deviation cannot be corrected thus is accounted in the form of uncertainty. This paper presents an average air kerma strength-based methodology which provides a simple and effective mechanism for estimating the conventional true value of air kerma rate at various distance which adds lower uncertainty to overall uncertainty, as compared to the method of using a fixed or reference distance (say 100 cm) based air kerma rate.</p></div>","PeriodicalId":689,"journal":{"name":"MAPAN","volume":"39 1","pages":"31 - 35"},"PeriodicalIF":1.0000,"publicationDate":"2023-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"MAPAN","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1007/s12647-023-00699-x","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"INSTRUMENTS & INSTRUMENTATION","Score":null,"Total":0}
引用次数: 0
Abstract
Laboratories/facilities dealing with ionizing radiation encounter radiation field which are measured using suitable gamma radiation monitors, for area and personal monitoring. These radiation monitors are subjected to periodic calibrations to confirm that they are still fit for the purpose. In India, periodic calibration of these radiation monitors is carried out by NABL accredited calibration laboratories using source exposure devices containing radionuclide sources of 137Cs and/or 60Co. Calibration laboratories get the output from these source exposure devices standardized by RSSD, BARC, Mumbai. RSSD, BARC, provides a report on the measured output, in the form of air kerma rates at different distances, which is traceable to relevant national standards. The laboratory then uses the standardized radiation field in day-to-day calibration, by taking air kerma rate mostly at distance of 100 cm (fixed distance) as reference for estimating radiation fields at other distances by using inverse square law. The air kerma rate values obtained by the using inverse square law shows deviation from the measured values with an allowed deviation up to 5%. The impact of this deviation cannot be corrected thus is accounted in the form of uncertainty. This paper presents an average air kerma strength-based methodology which provides a simple and effective mechanism for estimating the conventional true value of air kerma rate at various distance which adds lower uncertainty to overall uncertainty, as compared to the method of using a fixed or reference distance (say 100 cm) based air kerma rate.
期刊介绍:
MAPAN-Journal Metrology Society of India is a quarterly publication. It is exclusively devoted to Metrology (Scientific, Industrial or Legal). It has been fulfilling an important need of Metrologists and particularly of quality practitioners by publishing exclusive articles on scientific, industrial and legal metrology.
The journal publishes research communication or technical articles of current interest in measurement science; original work, tutorial or survey papers in any metrology related area; reviews and analytical studies in metrology; case studies on reliability, uncertainty in measurements; and reports and results of intercomparison and proficiency testing.