Tests and foreseen developments of fibered-OSLD gamma-heating measurements in low-power reactors
Abstract
In this paper, test measurements of a fibered optically stimulated luminescent dosimeter (OSLD) system performed during a dedicated experimental phase in EOLE zeropower reactor are presented. The measurement setup consists of an OSLD crystal connected onto the extremity of an optical fiber and a laser stimulation system, manufactured by the CEA/LIST, Saclay, France. The OSL sensor is remotely stimulated via an optical fiber using a diode-pumped solid-state laser. The OSL light is collected and guided back along the same fiber to a photomultiplier tube through appropriate optical filters. OSL signals are corrected for background noise and integrated to provide the absorbed doses thanks to calibration coefficients. The light stimulation also fully bleaches the crystal (reusable for the next measurement).
Results obtained using this system are compared to usual gamma-heating measurement protocol using OSLD pellets. Both measurement processes were calibrated to ensure the comparison of absolute doses in gray at the same positions in the core. The presence of induced radioluminescence in the OSLD during the irradiation was also observed and could be used to monitor the gamma flux. The feasibility of remote measurements is achieved, whereas further developments could be conducted to improve this technique since the readout procedure still requires to withdraw the OSLD off the gamma flux (hence from the core) on account of the dose rate (around a few Gy·h$^{-1}$ ), and the readout time remains quite long for online applications. Several improvements are foreseen and will be tested in the forthcoming years.
Keywords
Crystals
Optical fiber sensors
gamma-heating measurement protocol
gamma flux
OSLD pellets
light stimulation
OSL signals
OSL light
diode-pumped solid-state laser
OSL sensor
laser stimulation system
optical fiber
OSLD crystal
EOLE zeropower reactor
luminescent dosimeter system
low-power reactors
fibered-OSLD gamma-heating measurements
ionizing radiation
Optical Fiber Sensor
Distributed and Quasi-distributed sensing
sensor
instrumentation
nuclear instrumentation
laser
electronic architecture
signal processing
gamma-rays
radiotherapy
Irradiation
Nuclear heating
optical fibers
optically stimulated luminescent dosimeters (OSLD)
remote readout
calibration
dosimeters
dosimetry
fibre optic sensors
optical filters
photomultipliers
radiation therapy
Optical fiber testing
Radiation effects
Heating systems
Inductors