Gérard Sarrabayrouse

Radiation Monitoring in Mixed Environments at CERN: From the IRRAD6 Facility to the LHC Experiments

RadFET and p-i-n diode semiconductor dosimeters from different manufacturers will be used for radiation monitoring at the Experiments of the CERN LHC accelerator. In this work these sensors were exposed over three months in the CERN-IRRAD6 facility that provides mixed high-energy particles at low rates. The aim was to validate the operation of such sensors in a radiation field where the conditions are close to the ones expected inside full working LHC particle detectors. The results of this long-term irradiation campaign are presented, discussed and compared with measurements by other dosimetric means as well as Monte Carlo simulations. Finally, the integration of several dosimetric devices in one sensor carrier is also presented.

Sensitive Volume and Triggering Criteria of SEB in Classic Planar VDMOS

This paper presents 2-D numerical simulation results which allow the definition of the sensitive volume and triggering criteria of SEBs for VDMOS in classic planar-type technology. The results analysis allows for a better understanding of the SEB mechanism.

SEB characterisation of commercial power MOSFETs with backside laser and heavy ions of different ranges

This paper presents a validation of the methodology based upon backside laser irradiations to characterize the sensitivity of power devices towards single-event burnout. This is done thanks to high-energy heavy ion testing and device simulations.

Assessment of a new p-MOSFET usable as a doserate insensitive gamma dose sensor

The DGA/CEB has made an assessment of the dosimetric response of a single unbiased MOSFET gamma-radiation sensor, designed and created by LAAS-CNRS. This transistor is to be the sensor of a military personnel dosimeter to record gamma doses emitted at a doserate higher than 20 Gy/h.

MOS radiation dosimeter: sensitivity and stability

The main properties of MOS radiation dosimeters are presented. The sensitivity at high field ranges between 2 mV/Rad and 20 mV/Rad. The post-irradiation recovery can be as low as 0,1% for 1000 h at ambient temperature.<<ETX>>

A monolithic optical phase-shift detector on silicon

A novel monolithically integrated device used as an optical phase-shift detector is presented. It consists of a diffraction grating etched at the surface of a p-n photodiode fabricated by a process compatible with a standard silicon CMOS technology. When two coherent light beams are collimated toward the surface of the device, the detected optical power generates a current depending on the relative phase between the two incident beams. The operating principle of this detector and the results obtained by finite-difference time-domain modeling are presented. The fabrication process of the first devices is described and the experimental validation of the concept is demonstrated.

A monolithic phase measurement photodetector

A novel monolithically integrated photodetector used as an optical phase-shift sensor is presented It consists of a diffraction grating etched at the surface of a p-n photodiode fabricated by standard silicon CMOS technology. This device provides the phase relationship between two coherent light beams collimated toward the surface of the photodetector. The operating principle of this sensor is presented along with the first devices fabricated and the experimental validation of the concept is demonstrated by performance characterization.

Monolithic diffractive interference detector on silicon

The presented interference detector comprises a standard pn junction in a silicon substrate and a corrugation grating engraved at its surface. Two beams with unknown phase difference impinge onto the detector under the Littrow condition for some diffraction order of the grating. The detected power exhibits a non-zero AC component as the relative phase between the incident beams changes. The present paper describes the operation principle and brings the evidence of non-zero interference contrast in the application case of a displacement sensor.

Superficial photoluminescence and PV conversion of nanoscale Si-layered systems at 400 nm

A surprising photovoltaic (PV) conversion at 400 nm has been observed in nanoscale Si-layered systems (ns-Si-ls) during spectral response measurements. In conventional solar cells the UV and blue PV conversion may be poor because of the surface recombination within a thin superficial layer. In multi-interface novel devices (MIND) containing ns-Si-ls this conversion is always negligible within an even thicker surface dead zone from which practically no free-carriers can be collected. So the measured 400 nm band PV conversion in MIND cells is totally inconsistent with usually observed effects. Another CE paradox concerns its inversely proportional variation versus incident flux intensity, lower the intensity higher the CE, which value can even exceed unity. This new effect is also localized at the superficial nanostratum and originates from postimplantation defects and nanostructures formed during the implantation process. A similar low energy free-carrier generation has been observed recently in MIND cells with buried ns-Si-ls having a relatively very thin superficial stratum because of an excellent electronic passivation. No available publication mentions such an effect despite extensive investigations on the subject of structural and optical properties of Si nanoparticles, Si nanolayers, new Si-based materials such as semiconductor silicides and the luminescence-center doped Si materials. In this work, the carrier collection properties of the superficial Si nanostratum are reported and discussed in detail in relation to incident flux intensity. An additional low energy generation was observed experimentally. The effect could have capital importance for a breakthrough in the PV conversion efficiency in Si solar cells with nanotransformations.