Fiber Optic remote gamma dosimeters based on Optically Stimulated Luminescence: State-of-the-art at CEA

Optically Stimulated Luminescence (OSL) used in conjunction with optical fibres allows remote measurements of both dose and dose rate for the purpose of radiation protection in nuclear industry and medecine (radiology, radiotherapy), monitoring of installations (dismantling) as well as in process controls. Since 1995, two types of OSL systems have been developed by the Optical Measurement Laboratory (CEA) for gamma detection. The first system relies on rare-earth-doped Alkaline-Earth Sulphides and operates in the red/near-infrared part of the spectrum. It does not provide a tissue-equivalent dose measurement and is dedicated for dismantling operations and process control where a great fiber length is required (100 meters). Several systems of this kind are routinely used by COGEMA and CEA for assistance in their dismantling operations as they provide real-time in-situ operation in areas out of reach for usual dosimeters. The second system relies on alumina crystals and operates in the blue/green part of the visible spectrum. It has been developed for radiation protection purposes and may involve a patented compensation technique (both for angular incidence and photon energy).