Peter Križan, Ljubljana September 17, 2008 SuperB PID Peter Križan University of Ljubljana and J. Stefan Institute Forward PID: - SiPM as photon detectors – update - Forward region PID impact – new input

Peter Križan, Ljubljana September 17, 2008 SuperB PID SIPMs: improving signal/noise Improve the signal to noise ratio: Reduce the noise by a narrow (few ns) time window Increase the number of signal hits per single sensor by using light collectors and by adjusting the pad size to the ring thickness Light collector with reflective walls SiPM or combine a lens and mirror walls PCB

Peter Križan, Ljubljana September 17, 2008 SuperB PID Light guide should be as close as possible to the SiPM surface (now: air gap + epoxy layer)‏ Machined from a plastic plate (HERA-B RICH lens material). 1mm gap Light guide transmission 0.7 mm 1 mm Gap size (mm) Light collection: improve signal to noise ratio

Peter Križan, Ljubljana September 17, 2008 SuperB PID Cherenkov photons with light collectors Yield increase in agreement with the expectations Further improvements possible by Using SiPMs with a reduced epoxy protective layer using a better light collector First attempt: use the top of a blue LED Hits in Cherenkov space

Peter Križan, Ljubljana September 17, 2008 SuperB PID 1mm 2.5mm 4.3mm 10 o SiPM array with light guides Detector module design Aim: build a multi-channel module with light collectors and SiPMs on a printed board HERA-B RICH lens

Peter Križan, Ljubljana September 17, 2008 SuperB PID Light guide geometry optimisation

Peter Križan, Ljubljana September 17, 2008 SuperB PID Light guide geometry optimisation

Peter Križan, Ljubljana September 17, 2008 SuperB PID SiPMs: array of 8x8 SMD mount Hamamatsu S P with 0.3mm protective layer Detector module for beam tests at KEK SiPMs Light guides SiPMs + light guides 2cm

Peter Križan, Ljubljana September 17, 2008 SuperB PID SiPMs: array of 8x8 SMD mount Hamamatsu S P with 0.3mm protective layer 64 SiPMs 20mm Photon detector for the beam test

Peter Križan, Ljubljana September 17, 2008 SuperB PID

Peter Križan, Ljubljana September 17, 2008 SuperB PID

Peter Križan, Ljubljana September 17, 2008 SuperB PID

Peter Križan, Ljubljana September 17, 2008 SuperB PID Beam test set-up CERN, test beam, North area

Peter Križan, Ljubljana September 17, 2008 SuperB PID Beam test at CERN – last weekend

Peter Križan, Ljubljana September 17, 2008 SuperB PID Summary of beam tests Single Cherenkov photons were observed with SiPM RICH counter using cosmic rays and electron beam Different types of light guides were designed and studied A detector module was constructed using 8x8 array of MPPCs (SMD package) and a light guide array, and tested in the electron test beam Preliminary results of bench tests are roughly in agreement with expectations - further analysis is needed Beam test at CERN during the last week, data look OK, have to be analysed

Peter Križan, Ljubljana September 17, 2008 SuperB PID Open question: sensitivity to neutrons SiPMs are sensitive to neutron irradiation (dark count rate starts increasing drastically after ~10 10 neutrons/cm 2 )  We have to measure the neutron flux in the relevant detector region: calibrated Si diodes exposed in Belle in the winter/spring run period, have been extracted, to be determined: the integrated flux (fluence)  During the summer shut-down, we have also mounted a few SiPMs in the proper place in the spectrometer, will register their performance online during the 2008/09 running.

Peter Križan, Ljubljana September 17, 2008 SuperB PID Forward PID impact – some input As already reported some time ago, fast MC is in principle ready, could be built into the SuperB framework No manpower to work on this up to now... At the moment we only have Evgeniy’s results In the meantime, a study was carried out for the SuperKEKB by our colleagues at KEK. Their figures can be used to get a rough idea of what gains we are talking about. As test modes, B       were studied Results: luminosity gain B     B     (note the this is with respect to a spectrometer with a threshold Cherenkov counter in the forward region)