Skip to Main content Skip to Navigation
Theses

Développement d’un système de mesure ultra-compact à coïncidences électron/photon pour la détection et la caractérisation de radionucléides du xénon

Abstract : As part of the Comprehensive nuclear Test Ban Treaty (CTBT), an International Monitoring System (IMS) has been developed. This network consists of several hundred measuring stations whose role is to detect the signatures of a clandestine nuclear test. Four types of measurements are carried out: seismic, hydroacoustic, infrasound and radionuclide. In the particular case of an underground nuclear test, only the radionuclide measurement is adequate to detect the explosion and quantify its yield. Four xenon radionuclides with long half-lives are produced during a nuclear test: the 131m-Xe, the 133m-Xe, the 133-Xe and the 135-Xe. A small proportion of these gases may diffuse through the cracks in the cavity and end up in the atmosphere. Due to atmospheric dilution, the concentrations of these four radionuclides are extremely low and therefore difficult to detect. In addition, atmospheric background continues to increase as these radioactive gases are also produced by medical radioisotope facilities and nuclear power plants. In order to strengthen the IMS, the CEA-DAM has proposed to develop an ultra-compact and mobile system for detecting xenon radionuclides, in order to be able to carry out verification measurements directly on site, and thus to avoid the problem of atmospheric dilution. This work presents the development and optimization of this system. The system was first modelled on a computer and its performances in terms of detection efficiency were simulated by the Monte-Carlo method using Geant4 software. Measurements are made in electron-photon coincidence mode. In parallel, an ultra-compact acquisition chain has been developed, as well as a communication network to synchronize in time the various digital spectrometers used for signal processing (IEEE 1588 PTP protocol). The minimum detectable concentrations of this system are less than 5 mBq/m³ for a 12 h acquisition, for the four xenon radionuclides of interest.
Complete list of metadatas

Cited literature [395 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-02418010
Contributor : Abes Star :  Contact
Submitted on : Wednesday, December 18, 2019 - 2:49:11 PM
Last modification on : Monday, October 19, 2020 - 3:43:45 AM
Long-term archiving on: : Thursday, March 19, 2020 - 5:50:54 PM

File

83183_THOMAS_2019_archivage.pd...
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-02418010, version 1

Collections

STAR | CEA | DAM

Citation

Vincent Thomas. Développement d’un système de mesure ultra-compact à coïncidences électron/photon pour la détection et la caractérisation de radionucléides du xénon. Instrumentations et Détecteurs [physics.ins-det]. Université Paris Saclay (COmUE), 2019. Français. ⟨NNT : 2019SACLS454⟩. ⟨tel-02418010⟩

Share

Metrics

Record views

203

Files downloads

187