A Personal Dosimetry Intercomparison Study in Asian and Pacific Region

The IAEA/RCA (Regional Cooperative Agreement) project to strengthen and harmonize radiation protection infrastructures in Asian and Pacific region started in 1988. The number of the RCA member countries is 17 at present. In the early stages of the project, there was little information on the status of radiation protection and their technical abilities of radiation protection measurements in RCA member countries. Since individual monitoring for occupational protection was performed in every country where radiation was used industrially and/or medically, it was thought that the intercomparison of dosimetry services could bring fruitful results and provide a good index of the technical stages of member countries. The first RCA personal dosimeter intercomparison (Phase 1) was conducted during the years of 1990 1992. At that time few regional dosimetry services calibrated dosimeters on backscatter phantoms, so the intercomparisons were mainly conducted with the traditional physical quantity, exposure, in units of "R". The results of the first phase RCA personal dosimeter intercomparison were published [1], and the program was seen to have contributed significantly to the technical improvement of personal dosimetry systems of many RCA member countries. In 1990, the International Commission on Radiological Protection (ICRP) published new recommendations on radiation protection principles [2]. At about the same time, the International Commission on Radiation Units and Measurements (ICRU) defined a the new set of operational quantities for radiation protection [3, 4, 5, and 6]. These were recommended for use in the International Basic Safety Standards [7]. Furthermore, the International Standard Organization (ISO) proceeded with development of recommendations on the calibration methodology for radiation protection instruments for the operational quantities [8]. Increasing international use of the operational quantities was the primary motivation for initiating the second RCA intercomparison program for individual monitoring. In 1994, the RCA Workshop on Calibration of Dosimeters and Survey Instruments for Photons was held in Tokai, Japan and the operational quantities for individual monitoring were also discussed and the second dosimeter intercomparison was proposed and planned for the period 1995 1996. The objectives of the second phase personal dosimeter intercomparison were as follows;