Filters
Results 1 - 1 of 1
Results 1 - 1 of 1.
Search took: 0.033 seconds
AbstractAbstract
[en] For radiological cleanliness purpose, nuclear operators have to assess surface residual activity such as beta contamination. To this aim, contamination monitors are essential. In this context, EDF R and D proposed a research project in order to study the feasibility of an innovative contamination monitor to detect beta surface activity in situ which is until now performed ex situ. The main objective is to detect a 0.4 Bq/cm2 beta surface contamination in a high gamma background up to 100 μSv/h. This demands the detector to have a high beta/gamma discrimination performance. Several technologies based on scintillator and/or gas filled detector have been investigated. Geant4 simulations have been carried out to optimise the configuration of the chosen detector such as geometry, materials, etc. Two simulation-optimised prototypes based on Phoswich detectors have been developed and tested with beta and gamma sources in a laboratory framework (LPC Caen). Furthermore, two experimental campaigns have been conducted in a nuclear power plant (NPP of Chinon) in order to evaluate the performance of the developed prototypes in a realistic gamma background environment. The Geant4 simulations and the experimental work are discussed in this thesis. (author)
[fr]
A des fins de proprete radiologique, les exploitants nucleaires doivent evaluer l'activite surfacique residuelle, telle que la contamination beta. Pour cela, les contaminametres sont essentiels. Dans ce cadre, EDF R et D a propose un projet de recherche visant a etudier la faisabilite d'un contaminametre innovant permettant de detecter l'activite surfacique beta in situ, alors qu'elle est actuellement mesuree ex-situ.L'objectif principal de ce travail est de detecter une contamination beta surfacique de 0,4 Bq/cm2 dans un environnement gamma eleve, jusqu'a 100 μSv/h. Cela exige un detecteur ayant une performance de discrimination beta/gamma elevee. Plusieurs technologies basees sur un scintillateur et/ou un detecteur a gaz ont ete etudiees. Des simulations Geant4 ont ete effectuees pour optimiser la configuration des technologies retenues (geometrie, materiaux, etc.). Suite a ces simulations, deux prototypes, de type Phoswich, optimises ont ete fabriques et testes a l'aide de sources beta et gamma au laboratoire (LPC Caen). En outre, deux campagnes d'essai ont ete menees dans une centrale nucleaire (CNPE de Chinon) afin d'evaluer les performances des prototypes developpes dans un bruit de fond gamma realiste. Les simulations Geant4 et les tests sont discutes dans cette these. (auteur)Original Title
Etude de faisabilite d'un detecteur dedie a la discrimination beta/gamma
Primary Subject
Source
4 Dec 2018; 246 p; 90 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses; These de doctorat, Specialite: physique
Record Type
Miscellaneous
Literature Type
Thesis/Dissertation
Report Number
Country of publication
BACKGROUND NOISE, BETA DETECTION, CESIUM 137, CHINON-B1 REACTOR, COBALT 60, COINCIDENCE METHODS, COMPUTERIZED SIMULATION, DALITZ PLOT, FEASIBILITY STUDIES, G CODES, GAMMA DETECTION, OPTICAL FIBERS, PARTICLE DISCRIMINATION, PLASTIC SCINTILLATORS, PROPORTIONAL COUNTERS, RADIOMETERS, SURFACE CONTAMINATION, ZINC SULFIDES
BETA DECAY RADIOISOTOPES, BETA-MINUS DECAY RADIOISOTOPES, CESIUM ISOTOPES, CHALCOGENIDES, CHARGED PARTICLE DETECTION, COBALT ISOTOPES, COMPUTER CODES, CONTAMINATION, COUNTING TECHNIQUES, DETECTION, DIAGRAMS, ENRICHED URANIUM REACTORS, FIBERS, INFORMATION, INORGANIC PHOSPHORS, INTERMEDIATE MASS NUCLEI, INTERNAL CONVERSION RADIOISOTOPES, ISOMERIC TRANSITION ISOTOPES, ISOTOPES, MEASURING INSTRUMENTS, MINUTES LIVING RADIOISOTOPES, NOISE, NUCLEI, ODD-EVEN NUCLEI, ODD-ODD NUCLEI, PARTICLE IDENTIFICATION, PHOSPHORS, POWER REACTORS, PWR TYPE REACTORS, RADIATION DETECTION, RADIATION DETECTORS, RADIOISOTOPES, REACTORS, SCATTERPLOTS, SIMULATION, SULFIDES, SULFUR COMPOUNDS, THERMAL REACTORS, WATER COOLED REACTORS, WATER MODERATED REACTORS, YEARS LIVING RADIOISOTOPES, ZINC COMPOUNDS
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue