Validating a MCNPX Model of Mg(Ar) and TE(TE) Ionisation Chambers Exposed to 60Co Gamma-rays

For an accurate determination of the absorbed doses in complex radiation fields (e.g. mixed neutron-gamma fields), a better interpretation of the response of ionisation chambers is required. This study investigates a model of the ionisation chambers using a different approach, analysing the collected charge per minute as a response of the detector instead of the dose. The MCNPX Monte Carlo code is used. In this paper, the model is validated using a well-known irradiation field only: a 60Co source. The detailed MCNPX models of a Mg(Ar) and TE(TE) ionisation chamber is investigated comparing the measured charge per minute obtained free-in-air and in a water phantom with the simulated results. The difference between the calculations and the measurements for the TE(TE) chamber is within +2% whereas for the Mg(Ar) chamber is around 17%. The systematic discrepancy in the case of Mg(Ar) chamber is expected to be caused by an overestimation of the sensitive volume.

ROCA Antoaneta;  NIEVAART Victor Alexander;  MOSS Raymond;  STECHER-RASMUSSEN Finn;  ZAMFIR Nicolae Victor; 

2008-12-05

OXFORD UNIV PRESS

JRC48460

0144-8420,   

http://rpd.oxfordjournals.org/,    https://publications.jrc.ec.europa.eu/repository/handle/JRC48460,   

10.1093/rpd/ncm484,