The design of a new insert for calibration of LDR and HDR 192Ir sources in a well-type ionization chamber.

Abstract

Some well-type ionization chambers, present a very small sweet spot that are sufficient for small HDR sources. However, if a longer HDR source or LDR wires are calibrated, the positional uncertainty increases and an approximated correction factor must be applied, resulting in an increased uncertainty. One of the ways to avoid this problem would be to flatten the well chamber response by increasing its sweet spot region. This work uses the Monte Carlo code PENELOPE to simulate the response of a well-type chamber HDR-1000, with its original insert, by using an HDR 192Ir source and proposes a new insert design that increases its flatness region from 1.0 cm to approximately 4.0 cm (+/- 2.0 cm about the peak response).