Set up and test of an anticoincidence system for the detection of radioactive xenon by gamma spectrometry system

Hassan Mubashir; Mohamed Mahmoud Mounja; Stefano Salvi; Chiara Telloli; Flavio Cicconi; Antonietta Rizzo

doi:10.1016/j.jenvrad.2022.107107

Set up and test of an anticoincidence system for the detection of radioactive xenon by gamma spectrometry system

J Environ Radioact. 2023 Apr:259-260:107107. doi: 10.1016/j.jenvrad.2022.107107. Epub 2023 Jan 14.

Authors

Hassan Mubashir¹, Mohamed Mahmoud Mounja², Stefano Salvi³, Chiara Telloli⁴, Flavio Cicconi³, Antonietta Rizzo³

Affiliations

¹ Electrical Engineering Department, Bologna University, Viale del Risorgimento 2, Bologna, Italy.
² ARSN, Mauritanian National Authority of Radiation Protection, Nuclear Security, and Safety, Nouakchott, Mauritania.
³ ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development Fusion and Technology for Nuclear Safety and Security Department Nuclear Safety, Security and Sustainability Division, via Martiri di Monte Sole 4, Bologna, Italy.
⁴ ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development Fusion and Technology for Nuclear Safety and Security Department Nuclear Safety, Security and Sustainability Division, via Martiri di Monte Sole 4, Bologna, Italy. Electronic address: chiara.telloli@enea.it.

PMID: 36646011
DOI: 10.1016/j.jenvrad.2022.107107

Abstract

The aim of this work is based on the optimisation of a gamma spectrometry system in anticoincidence for the detection of noble gases, in particular the radioactive isotopes of xenon. These four radionuclides are of particular interest for the Comprehensive Nuclear Test-Ban Treaty (CTBT). The Laboratory of the ENEA Research Centre of Brasimone, where the experimental apparatus has been set up to carry out the measurements of ^131mXe, ¹³³Xe, ^133mXe and ¹³⁵Xe, is able to provide, if necessary, data and analysis on noble gases. The apparatus provides for the sampling of outdoor air, the passage through filters and in activated carbons maintained at cryogenic temperatures to allow xenon absorption. Finally, gas extraction and xenon volumes are analyzed by means of gas chromatography and a thermal conductivity detector. At the end of the extraction an aluminium cylinder containing radioxenon is analyzed by high resolution gamma spectroscopy using a High Purity Germanium Detector P-type. The signals produced by the interaction of cosmic rays with the crystal have been recognized as the main cause of the increase of the detector background because they give rise to the Compton continuum and, as a result, they affect the value of the minimum detectable activity (MDA). In order to overcome this effect, a system in anticoincidence has been developed using two plastic scintillators, placed over the shielding of the HPGe detector, which send pulses recording within a time delay window located in the germanium multichannel analyzer: at the time the signal arrives from the scintillator, the gate blocks data acquisition to avoid recording pulses generated by cosmic radiation. For both configurations of the system (with and without the anticoincidence apparatus operating) the energy, and efficiency calibrations have been carried out using a certified multigamma-ray calibration source to assess the performance.

Keywords: Anticoincidence system; HPGe detector; Plastic scintillator; Radioxenon.

MeSH terms

Air Pollutants, Radioactive* / analysis
Germanium* / analysis
Radiation Monitoring* / methods
Radioisotopes / analysis
Spectrometry, Gamma
Xenon / analysis
Xenon Radioisotopes / analysis

Substances

Xenon
Xenon Radioisotopes
Germanium
Air Pollutants, Radioactive
Radioisotopes