Development of energy compensated Geiger Muller detector based on the T2416A Canberra Co. GM detector

Abstract

Geiger Muller counters have been a fundamental device in radiation detection for decades due to their simplicity and low cost. Canberra Company has been designing and manufacturing Geiger Muller detectors in various designs for radiation monitoring and field characterization. However, these devices have a draw back when it comes to radiation activity measurements due to the over response of the detector in low energy range i.e., 20 - 250 keV. One of the widely used Geiger Muller counter in the industrial sector is the T2416A. This device is used not only as a survey meter in high intensity gamma radiation fields, but also as a detection device employed in different survey meters for calibration purposes. Among such instruments one can cite the Inspector 1000 and the RadiaGem system. The T2416A GM detector has an over response in the low energy region of about a factor of 6 to 40 relative to 137Cs energy (i.e. 662 keV). In an attempt to flatten this response, in this study, the counter has been redesigned to be an energy compensated Geiger Muller counter. To achieve this goal, a special filtering material has been designed with a composition of different materials and in different thicknesses. The work has been carried out by adopting an approach of simulating the response of the detector with different materials as well as measurements at different photon energies up to 250 keV with and without filtering materials. A series of experimental and simulation data has been analyzed and compared against each other.