IN SITU SURFACE ELASTIC WAVE STUDY OF THE METAL - ELECTROLYTE INTERFACE

Les procès d'electrochimie sur des interface métal-électrolyte et absorption d'hydrogène dans les minces couches superficielles influencent comme on peut voir, pour propagation des élastique ondes superficielle.Some electrochemical processes on the metal - electrolyte interface and an absorption of hydrogen within a thin subsurface layer were shown to affect the propagation of the surface elastic waves

A Highly Efficient, Angle-Insensitive Solar Quantum Concentrator Based on Microstructured Plastic Optical Fiber

International audienceA new device made of very specific microstructured fluorescent plastic optical fibers, capable of concentrating solar radiation towards photovoltaic solar cells is studied in the QUYOS project. This device transforms a multidirectionnal and polychromatic flux of solar light to a monochromatic and monodirectionnal intense flux of light with a high conversion efficiency. The very specific behaviour of these fibers is due to the convergence of several quantum phenomena. Mainly the coincidence of the fluorescent band of the dye with the forbidden band of the photonic crystal from the microstructured fiber restricts the phase space of desexcitation only along the axis of the fiber. Moreover, a coupling of the fluorescence with the allowed modes of the central waveguide of the fiber does enhance the radiative desexcitation thanks to the Purcell effect

Fabrication of ultra-low radioactivity detector holders for Edelweiss-II

International audienceIn its first stage, the EDELWEISS-II dark matter experiment will use 21×320 g ionization-heat bolometers with NTD thermal sensors. To improve the present sensitivity of EDELWEISS to WIMP interactions by a further factor 100, ultra-low radioactivity detector holders exclusively made of copper and Teflon have been designed. The new design is using the relative expansion coefficients of copper, Teflon and germanium to hopefully ensure a dissipation-free detector holding. In order to validate this new holder, we need to compare the vibration behavior of the old holder and the new one. The amplitude of the bolometer vibrations is measured using the variation of capacitance between electrodes sputtered on the Ge crystal and reference electrodes fixed above the detector holders. We present noise measurements and compare them to the equivalent measurements using the detector holders of the Edelweiss-I experiment, which gave very satisfying results

Reinigung metallhaltiger Loesungen durch Festbettelektrolyse - Prozesstechnik Abschlussbericht. Abschlussdatum: Juli 1981

Technische Informationsbibliothek Hannover: RN 2598 (82-007)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Trimethyl Bismuth Optical Properties for Particle Detection and the CaLIPSO Detector

International audienceTrimethyl bismuth (TMBi) is a "heavy" transparent and dielectric organometallic liquid. This paper focuses on the measurement of TMBi's optical properties relevant for particle detection. We measured the TMBi transmission curve and refraction index versus wavelength, as well as the light production yield and the timing performance on a small size cell

CaLIPSO: An Novel Detector Concept for PET Imaging

International audienceThe CaLIPSO project focuses on the development of an innovative energetic-photon detector. The detector uses a "heavy" organometallic liquid: the TriMethyl Bismuth (TMBi), 82% by weight of Bismuth. TMBi efficiently converts through the photo-electric effect photons of energies below 1 MeV. The ionisation signal and light produced in the liquid are both detected. Beyond the measurement of gamma photon energies, this detector will allow locating photon interactions in the detector in three dimensions down to 1 mm3 and a sub nanosecond timing accuracy. All these desirable properties can be obtained simultaneously with liquid TMBi detector