Simulation of the response of an ionization chamber to 214Bi emission. Application to the measurement of 222Rn.

ABSTRACT

PENELOPE simulations of a Vinten ionization chamber (IC) were performed to investigate the influence of the thickness of glass-ampoules used in 222Rn standardization. The simulation reveals a non-negligible variation of the energy deposited in the chamber gas region (which may induce a proportional variation of the measured current) when considering the ß transition emissions of the daughters of 222Rn. This reinforces the idea of using a specialist container (made of metal to preserve the integrity of the container) that would circulate between the metrology laboratories in the context of international comparison exercises using the BIPM international reference system (SIR).