Article

Toward an usage of americium-241 for filter calibration

¹ Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES/SCA/LPMA, F-91400 Saclay, France
² Université Paris Saclay, CEA, LIST, Laboratoire National Henri Becquerel (LNE-LNHB), F-91120 Palaiseau, France

^* Corresponding author: gregoire.dougniaux@irsn.fr

Received: 8 November 2024
Accepted: 28 November 2024

Abstract

In nuclear safety and environmental studies, it is necessary to measure the activity of aerosols collected on filters. The calibration of these filters’ measurement chains currently involves producing a reference filter with a controlled deposit of aerosol marked by a specific radionuclide. In France, commonly used radionuclides include ¹³⁷Cs for gamma or beta emitters, ⁹⁰Sr/⁹⁰Y for beta emitters, and ²³⁹Pu for alpha emitters. However, using ²³⁹Pu presents several issues, notably the destruction of the filter required to determine its traceable activity and the associated uncertainties. The challenge of this project is to propose a radionuclide enabling non-destructive, SI-traceable measurement while retaining the reference filter. The proposed radionuclide is ²⁴¹Am, which is both alpha and gamma-emitting and allows for precise non-destructive measurements. Reference filters are produced on the IRSN’s ICARE test bench with calibrated aerosols tagged with ²⁴¹Am. The reference activity of theses filters is measured by gamma spectrometry on CEA/LNHB reference counter. A series of tests confirmed that ²⁴¹Am provides accurate activity determination with minimal uncertainty. Consequently, adopting ²⁴¹Am can significantly improve the reliability of radioactive contamination monitoring while avoiding practical challenges associated with plutonium.