Calibration of gamma spectrometers in regional laboratories and the laboratories in the Ministry of ecology and water

The calibration of the low-background gamma spectrometers in Bulgaria cover all the regional laboratories and the laboratories of the Ministry of Ecology, as well as other laboratories around the country. The regional laboratories for complete spectrometric analysis have been established in 1988 after the Chernobyl accident. In this calibration 25 standard sources have been used, prepared in the Institute of Nuclear Research and Nuclear Energy. The methodology of the calibration is described in details. In most of the cases the measured relative efficiency of the detectors is in compliance with the documentation. In a few cases significant differences are detected. Some of the laboratories took part in the interlaboratory comparison and the results are given at the seminar. The measurements show the state of the regional laboratories and problems to be solved. The main problems are: absence of the regulations for the operation of the laboratories and their place in the structure of the radiation protection system in Bulgaria; financial problems; software problems; need of reconsidering of the placement of the equipment