Decay of $^{99m}$Tc as part of calibration procedure for $^{192}$Ir activity measurements using a well type ionization chamber

TL;DR

This paper investigates the non-linear response of an ionization chamber during calibration of $^{192}$Ir activity measurements, identifying electrometer range switching as the main cause and proposing a correction method for accurate $^{99m}$Tc activity determination.

Contribution

It introduces a model to correct non-linearity in ionization chamber response, improving the accuracy of $^{99m}$Tc activity measurements during calibration.

Findings

Non-linearity caused mainly by electrometer range switching.

The proposed correction method yields accurate $^{99m}$Tc activity measurements.

The model assumes non-linearity does not affect the decay constant.

Abstract

In this work the linearity in the response of an ionization-chamber as a function of $^{99m}$Tc activity was checked as part of a calibration procedure for $^{192}$Ir activity measurements. The non-linearity was found to be caused mainly by the electrometer range switching. A model based on the hypothesis that the non-linear effect did not influence the decay constant was tested. This method allowed to correct the non-linear effect and obtain the 99mTc activity with good acuracy.