Feasibility study of a current mode gamma radiation dosimeter based on a commercial pin photodiode and a custom made auto-ranging electrometer

Marko Andjelkovic, Goran Ristic
2013 Nuclear Technology and Radiation Protection  
Ap plied Phys ics Lab o ra tory (APL), Fac ulty of Elec tronic En gi neer ing, Uni ver sity of Niš, Niš, Ser bia Sci en tific pa per An ex per i men tal study has been con ducted to eval u ate the fea si bil ity of a cur rent mode gamma ra di a tion do sim e ter, con sist ing of a com mer cial PIN photodiode as a ra di a tion sensor, and a cus tom made auto-rang ing electrometer for real-time mea sure ment of the PIN photodiode's re sponse un der ra di a tion ex po sure. The ra di a tion in
more » ... d di rect cur rent response for sin gle PIN photodiodes with dif fer ent ac tive ar eas, as well as for mul ti ple PIN photodiodes con nected in par al lel, has been in ves ti gated. Three types of com mer cial sil i con PIN photodiodes have been cho sen for eval u a tion -S1223, BPW34, and PS100-6-CER2 PIN. Dur ing the ex per i ment, five sam ples have been tested -three sam ples made of sin gle PIN photodiodes (one sam ple of each photodiode type) and two sam ples formed by con necting mul ti ple photodiodes in par al lel (two BPW34 photodiodes in par al lel and four BPW34 photodiodes in par al lel). The sam ples have been ir ra di ated with a 60 Co gamma ray source and the re la tions be tween the in duced photocurrent and the dose rate, and be tween the ac cu mulated charge and the ab sorbed dose, have been de ter mined. For mea sur ing the photodiodes re sponse, a cus tom made auto-rang ing electrometer con trolled by a per sonal com puter, and ca pa ble of mea sur ing di rect cur rents from 50 pA to 10 mA with rel a tive er ror less than 2.5%, has been used. Ob tained re sults have shown very good lin ear ity be tween the dose rate and the in duced photocurrent for dose rates rang ing from 0.93 Gy/h to 67 Gy/h. Also, very good linear ity has been ob served be tween the ac cu mu lated charge and the ab sorbed dose for all tested sam ples, within the in ves ti gated range of ab sorbed doses from 472 mGy to 3.3 Gy. On the basis of the ob tained re sults, a sim ple model has been de rived, en abling the es ti ma tion of the photodiode's cur rent re sponse as a func tion of the dose rate and the photodiode's ge om e try (ac tive area and de ple tion layer width). Key words: cur rent mode ra di a tion do sim e ter, PIN photodiode, auto-rang ing electrometer M. S. Andjelkovi}, et al.: Fea si bil ity Study of a Cur rent Mode Gamma Ra di a tion .
doi:10.2298/ntrp1301073a fatcat:zyp3ftjsdzb3xoa5qhjuzhqkiq