engleski

Secondary standard dosimetry laboratory at the Ruđer Bošković Institute

The Secondary Standard Dosimetry Laboratory at the Ruđer Bošković Institute, Zagreb, Croatia, was installed during the several last years. The installation of this Laboratory was strongly supported by the International Atomic Energy Agency (IAEA) through the Technical Cooperation Project (CRO 1/004/ ; Establishing Calibration Services). Inside the country this Technical Cooperation Project was supported by the State Office for Standardization and Metrology, State Office for Radiation Protection and the Ministry of Health of the Republic of Croatia. The Secondary Standard Dosimetry Laboratory at the Ruđer Bošković Institute, Zagreb, Croatia was installed in two calibration rooms. The both of these calibration rooms are 9.6 meters long and 6 meters wide. In the both of these calibration rooms the proper climatization was installed. The walls of the both calibration rooms are thick enough (1 meter of concrete) and the entrance doors are protected by Pb to protect any radiation hazard in control rooms, in neighbouring rooms and in environment. In the first calibration room, placed in the basement, two sealed sources share the same calibration bench (produced by Hopewell Designs, Inc., USA) between them which is 6 meters long. On one side is Co-60 source of the 30 TBq activity (December 2004) for the calibration of radiotherapy ionizing chambers and the other equipment in the field of high dose rate range. On the other side is irradiation unit consists of 2 sealed sources for radiation protection purposes: (1) Cs-137 source, activity of 740 MBq (February 2004) and (2) Co-60 source, activity of 185 MBq (February 2004). For this second source three attenuators are provided that give a nominal attenuation of x10, x100 and x1000. In the second calibration room placed just above the first one the X-ray unit (gift from PTB, Germany, ISOVOLT 420, 40-300 kV, 1-20 mA) is placed. In front of this are: (1.) Aperture Wheel Assembly designed to modifay the beam diameter of the X-ray to meet the various beam configurations required for calibration instruments, (2.) a set of Filter Assembly to produce the beam definition as called for in the ISO 4037-3, and (3.) the Half-Value Layer Kit, all of them in front of calibration bench (produced by Hopewell Designs, Inc., USA) 5 meters long.

SSDL; gamma ray sources; dosimeters; calibration

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