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International audience; Optoelectronic components are the most sensitive devices of systems exposed to radiation environments. Displacement damage (DD) effects can severely degrade the performances of such devices, which are extensively used in critical electronic systems installed in particle accelerators or nuclear power plants. This work investigates the use of application-specific radiation spectra for damage estimations in operation instead of mono-energetic proton or neutron irradiations. An analysis of the characteristics of the Large Hadron Collider (LHC) radiation environment in terms of DD is presented in this work along with the demonstration of the ability of the CERN High Energy Accelerator Mixed Field (CHARM) facility of CERN to reproduce them. Then, a set of optocouplers made of gallium arsenide (GaAs), indium gallium arsenide (InGaAs), and aluminum gallium arsenide (AlGaAs) are tested under these environments, and the results are compared to proton and neutron irradiations.

International audience; The Low Power GigaBit Transimpedance Amplifier (lpGBTIA) is the optical receiver amplifier in the lpGBT chipset. It is a highly sensitive transimpedance amplifier designed to operate at 2.56 Gbps. It is implemented in a commercial 65 nm CMOS process. The device has been designed for radiation tolerance and, in particular, to accommodate the radiation effects in photodiodes that manifest themselves as an increase of both their dark current and junction capacitance. The optical receiver consisting of the lpGBTIA connected to an InGaAs photodiode has been successfully tested and irradiation tests showed that the power penalty remains below 4 dBm for exposition to a very high neutron fluences of the order of 10$^{15}$ n/cm$^2$.

International audience; In this work, a new method of qualifying COTS-based optocouplers adapted to the neutron dominated LHC radiation environment is studied. The responses of components made of different materials irradiated with protons and neutrons are analyzed.

We report on the first Q^{2}-dependent measurement of the beam-normal single spin asymmetry A_{n} in the elastic scattering of 570 MeV vertically polarized electrons off ^{12}C. We cover the Q^{2} range between 0.02 and 0.05 GeV^{2}/c^{2} and determine A_{n} at four different Q^{2} values. The experimental results are compared to a theoretical calculation that relates A_{n} to the imaginary part of the two-photon exchange amplitude. The result emphasizes that the Q^{2} behavior of A_{n} given by the ratio of the Compton to charge form factors cannot be treated independently of the target nucleus.

9 pp. (2007)., Displacement damage caused by fast neutrons in unbiased Gallium Arsenide (GaAs) Light Emitting Diodes (LED) resulted in a reduction of the light output. On the other hand, a similar type of LED irradiated with gamma rays from a 60Co source up to a dose level in excess of 1.0 kGy (1.0 × 105 rad) was found to show no significant drop of the light emission. This phenomenon was used to develop a low cost passive fluence monitor and kerma dosemeter for accelerator-produced neutrons. These LED-dosemeters were used to assess the integrated fluence of photoneutrons, which were contaminated with a strong bremsstrahlung gamma-background generated by the 730 MeV superconducting electron linac of the FLASH (Free Electron Laser at Hamburg) at Deutsches Elektronen-Synchrotron (DESY). The applications of GaAs LED as a routine neutron fluence monitor and displacement damage precursor for the electronic components located in high-energy accelerator environment are highlighted

17 pp. (2007)., Sophisticated electronic devices comprised of sensitive microelectronic components have been installed in the close proximity of the 720 MeV superconducting electron linear accelerator (linac) driving FLASH, the Free Electron Laser in Hamburg, presently in operation at DESY in Hamburg. Microelectronic chips are inherently vulnerable to ionising radiations, usually generated during routine operation of high-energy particle accelerator facilities like FLASH. Hence, in order to assess the radiation effect on microelectronic chips and to develop suitable mitigation strategy, it becomes imperative to characterise the radiation field in the FLASH environment. We have evaluated the neutron and gamma energy (spectra) and dose distributions at critical locations in the FLASH tunnel using superheated emulsion (bubble) detectors, GaAs light emitting diodes (LED), LiF-Thermoluminescence dosimeters (TLD) and radiochromic (Gafchromic EBT) films. This report highlights the application of the passive dosimeters for an accurate analysis of the radiation field in produced by high-energy electron linear accelerators.