4 research outputs found
PREPARATION OF THE POLYMERIC COMPOSITES OF BASED ON CHITOSAN AND POLYVINYLPYRROLIDONE
The process of the preparing compositions based on chitosan and water-soluble monomer N-vinylpyrrolidone in the presence of ammonium persulfate polymerization initiator are deter-mined. The viscometric studies in the presence of chitosan solutions of ammonium persulfate are conducted. The optimum conditions for the synthesis of copolymers with chitosan and polyvinylpyrrolidone (temperature, pH, mixing ratio) are proposed
First demonstration of in-beam performance of bent Monolithic Active Pixel Sensors
International audienceA novel approach for designing the next generation of vertex detectors foresees to employ wafer-scale sensors that can be bent to truly cylindrical geometries after thinning them to thicknesses of 20-40m. To solidify this concept, the feasibility of operating bent MAPS was demonstrated using 1.53cm ALPIDE chips. Already with their thickness of 50m, they can be successfully bent to radii of about 2cm without any signs of mechanical or electrical damage. During a subsequent characterisation using a 5.4 GeV electron beam, it was further confirmed that they preserve their full electrical functionality as well as particle detection performance. In this article, the bending procedure and the setup used for characterisation are detailed. Furthermore, the analysis of the beam test, including the measurement of the detection efficiency as a function of beam position and local inclination angle, is discussed. The results show that the sensors maintain their excellent performance after bending to radii of 2cm, with detection efficiencies above 99.9% at typical operating conditions, paving the way towards a new class of detectors with unprecedented low material budget and ideal geometrical properties