Investigation of a SiPM-GGAG:Ce,B scintillator detector for environmental gamma radiation monitoring

A study of a silicon photomultiplier (SiPM) coupled with a GGAG:Ce,B scintillator detector for environmental gamma radiation monitoring is presented in this paper. FLUKA based Monte Carlo simulations were carried out for the optimization of scintillator material and geometry for this application. Based on the simulation study, the dimensions of GGAG:Ce,B scintillator crystal were finalized and the scintillator was prepared. The detector was assembled by optically coupling to a commercially available SiPM. The analog output pulses of the SiPM were amplified by a voltage sensitive amplifier and subsequently counted using a microcontroller. The linearity of the detector response with gamma dose rate was verified using Cs-137 standard gamma source. The radiation response of the detector for different gamma energies was investigated using standard Cs-137, Am-241 and Co-60 sources. The variation of detector sensitivity with SiPM overvoltage was measured for choosing an optimal overvoltage for the SiPM operation. The experimentally observed response of the SiPM-GGAG:Ce,B detector was very linear in the measurement range of 3.5-300 mu Gy/h with a sensitivity of 2.44 cps/pGy/h. The gamma response study of the detector confirm the suitability of the developed detector for making a compact and low power gamma monitor for environmental gamma radiation monitoring network.