BER US ING GEANT 4 MONTE CARLO SIM U LA TIONS by Abid HUSSAIN , Sikander M . MIR ZA , Nasir

GEANT4 based Monte Carlo sim u la tions have been car ried out for the de ter mi na tion of ef fi ciency and con ver sion fac tors of a gas-flow ion iza tion cham ber for beta par ti cles emit ted by 86 dif fer ent ra dio iso topes cov er ing the av er age-b en ergy range of 5.69 keV-2.061 MeV. Good agree ments were found be tween the GEANT4 pre dicted val ues and cor re spond ing ex per i men tal data, as well as with EGS4 based cal cu la tions. For the re ported set of b-emit ters, the val ues of the con ver sion fac tor have been es tab lished in the range of 0.5×1013-2.5×1013 Bqcm–3/A. The com puted xe non-to-air con ver sion fac tor ra tios have at tained the min i mum value of 0.2 in the range of 0.1-1 MeV. As the ra dius and/or vol ume of the ion cham ber in creases, con ver sion fac tors ap proach a flat en ergy re sponse. These sim u la tions show a small, but sig nif i cant de pend ence of ion iza tion ef fi ciency on the type of wall ma te rial.