Investigations on α-AlO thermoluminescence for dosimetry of high energy photons.

This article presents a study of high-energy X-ray dosimetry carried out at CEA Gramat. In this study, we are interested in alumina as a new thermoluminescent dosimeter. We performed several pre-irradiation protocols to use alpha-alumina as a dosimeter over doses ranging from 0.

Monitoring of Ultra-High Dose Rate Pulsed X-ray Facilities with Radioluminescent Nitrogen-Doped Optical Fiber.

We exploited the potential of radiation-induced emissions (RIEs) in the visible domain of a nitrogen-doped, silica-based, multimode optical fiber to monitor the very high dose rates associated with experiments at different pulsed X-ray facilities. We also tested this sensor at lower dose rates associated with steady-state X-ray irradiation machines (up to 100 keV photon energy, mean energy of 40 keV). For transient exposures, dedicated experimental campaigns were performed at ELSA (Electron et Laser, Source X et Applications) and ASTERIX facilities from CEA (Commissariat à l'Energie Atomique-France) to characterize the RIE of this fiber when exposed to X-ray pulses with durations of a few µs or ns.

Study of silica-based intrinsically emitting nanoparticles produced by an excimer laser.

We report an experimental study demonstrating the feasibility to produce both pure and Ge-doped silica nanoparticles (size ranging from tens up to hundreds of nanometers) using nanosecond pulsed KrF laser ablation of bulk glass. In particular, pure silica nanoparticles were produced using a laser pulse energy of 400 mJ on pure silica, whereas Ge-doped nanoparticles were obtained using 33 and 165 mJ per pulse on germanosilicate glass. The difference in the required energy is attributed to the Ge doping, which modifies the optical properties of the silica by facilitating energy absorption processes such as multiphoton absorption or by introducing absorbing point defects.

Pixel pitch and particle energy influence on the dark current distribution of neutron irradiated CMOS image sensors.

The dark current produced by neutron irradiation in CMOS Image Sensors (CIS) is investigated. Several CIS with different photodiode types and pixel pitches are irradiated with various neutron energies and fluences to study the influence of each of these optical detector and irradiation parameters on the dark current distribution. An empirical model is tested on the experimental data and validated on all the irradiated optical imagers.

Production of mycophenolic acid by Penicillium roqueforti strains.

Sixteen strains of Penicillium roqueforti Thom, isolated from blue-molded cheeses, were studied. In vitro, all of these strains produced mycophenolic acid, some on the order of 0.8 to 4 mg/g od dry culture.