The Thin Light Trigger for the UA9 experiment

We realized a Thin Light Trigger (TLT) device based on thin plastic scintillator layer and Multi Pixel-Photon Counters (MPPC) readout, controlled via Ethernet, for the H8 telescope of the UA9 experiment. The UA9 experimental equipment was installed in the CERN-SPS in the 2009. The UA9 goals are to demonstrate the feasibility of a collider collimation scheme with a crystal as the primary collimator Measurements of suitable crystals are being carried out in the SPS ring as well as in a fixed target experiment at the H8 line in the CERN North experimental area. The aim of the TLT is to supply an upstream trigger for the H8 beam line telescope in order to select incoming protons. It has to be thin enough to minimize multiple scattering, which increases angular divergence, and hadronic interaction probability but it has to be sufficiently thick to yield enough light. The detector is made up of a 9×9 mm2 scintillator window, made up of 2 layers of scintillating fibers, coupled with 4 Multi Pixel-Photon (MPPC). Hamamatsu S10362-33 MPPC are driven by an embedded board supplying bias voltage and analog readout channels made up of low-noise, high gain, fast recovery voltage amplifiers. ARDUINO based control electronics allows temperature monitoring and gain calibration of MPPC by Ethernet with a simple html-based user interface. TLT system was tested in June 2013 at The DAFNE Beam-Test Facility (LNF - Frascati (RM)) by fine-adjustable-multiplicity 500MeV electron´s beam.