Performance tests of the B-RAD radiation survey meter

This article discusses performance tests of the B-RAD by ELSE NUCLEAR. The B-RAD is a portable survey meter for l. 101 γ-ray spectrometry and l. 101 γ-ray dose rate measurements able to operate in the presence of a strong magnetic field. The detector uses a 15 mm right cylinder LaBr 3 crystal coupled with a 16-pixel Silicon Photomultiplier array. The crystal, the photodetector and the front-end electronics (the probe) are enclosed in a case connected with a cable to a control unit. The latter includes the main electronics, a customised battery pack, two displays and a Faraday cage. More in detail, this paper investigates the instrument performance inside magnetic field, including linearity of its response and its angular response. An operational test is also reported to demonstrate a practical application. The performed tests show that the B-RAD can TI:\query[no=73,change=ferrullifrancesca@gmail.com]Q3 qid="AUT009": Please confirm that the provided email "ferrullifrancesca@gmail.com" is the correct address for official communication, else provide an alternate e-mail address to replace the existing one, because private e-mail addresses should not be used in articles as the address for communication. operate inside magnetic fields up to 2.5 T. Two small shortcomings were observed: a pulling force is felt especially on the control unit, which becomes rather intense for values of the magnetic fields above 1 T, and a slight reduction of the signal gain with increasing magnetic field intensity when the control unit is inside the field. The latter causes a variation of the measured dose rate of less than 10% at 1.5 T. The response of the B-RAD with dose rate is linear up to 20 mSv/h with discrepancies between the reference and the measured dose rate within 10%. The response is isotropic from −120° to ＋120°; beyond this limit the measured dose rate drops by 66% probably because of the scattering of the source photons with the case and some shielding effects.