COMPARATIVE-STUDY OF WLS FIBERS FOR THE ATLAS TILE CALORIMETER

The Wave Length Shifting (WLS) fibres are one of the most important co mponents of the ATLAS barrel hadronic tile calorimeter (Tilecal). The fibres collect the light produced in the injection molded scintillatin g tiles and transport it to the photomultipliers. Parameters like atte nuation length and light yield are important, as well as flexibility a nd radiation hardness. Comparative results of WLS fibres-produced by B icron, Kuraray and Pol.Hi.Tech are presented. The performance of the f ibres BCF91A from Bicron and S048 from Pol.Hi.Tech was significatively improved, but the most performant are still the double clad Y11 fibre s from Kuraray.