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La nuova elettronica di front-end per il rivelatore RICH di COMPASS Michela Chiosso Università di Torino – Dip. di Fisica Generale INFN – Sezione di Torino 1th Congressino di Dipartimento Dip. di Fisica Generale A. Avogadro, 7- 8 Aprile 2008. Outline. Cherenkov counters
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La nuova elettronica di front-end per il rivelatore RICH di COMPASS Michela Chiosso Università di Torino – Dip. di Fisica Generale INFN – Sezione di Torino 1th Congressino di Dipartimento Dip. di Fisica Generale A. Avogadro, 7- 8 Aprile 2008
Outline Cherenkov counters The COMPASS RICH: general description the multi-anode photomultipliers photon-detection the read-out electronics CMAD-V3, a new front-end chip for the multi-anode photomultipliers
The COMPASS experiment COmmon Muon Proton Apparatus for Structure and Spectroskopy 270 physicists, 25 institutes, 11 countries nucleon structure measurements hadron spectroscopy measurements
The COMPASS spectrometer COmmon Muon Proton Apparatus for Structure and Spectroskopy
Rich detector: a cherenkov counter Particella carica Cherenkov Effect cosqc = 1/bn The ingredients: 1. Radiator 2. Light collector 3. Large area photon detectors minimizing sp.e maximizing Np.e.
Cherenkov Light Imaging Technique:the first paper . . . . . . . . . . .
RICHRing Image Cherenkov 1977 Ypsilantis & Seguinot Gaseous radiator; image focusing by spherical or parabolic mirrors Particle Identification COMPASS RICH gaseous radiator
COMPASS RICH Radiator C4F10 transmittance > 80% (l=165 nm) n=1.0015 Light collector 2 spherical mirrors: total surface = 21m2 Angular acceptance: ± 250 mrad horizontal; ± 180 mrad vertical Photon-detectors 12 MWPC with CsI photocathodes 4 camera with multianode photomultipliers
The photon detectors MWPCs with CsI Photocathodes (already in use since 2001) FAST photon detection system • MAPMTs 576 in total • telescopes of fused silica lenses • read-out electronics: sensitive FE: MAD4 chip TDC: F1 Time resolution: few ns MAPMT aspherical surface spherical surface planar surface
A photon-detector view… Outside MAD4 + F1 CsI MWPC MaPMT Inside
Phast photo-detection system Photon detectors : MAPMT • wide wavelength range • time resolution < 1 nsec • adequate for high rate operation – up to which rate ? • robust Summarising: • good for next RICH generation • but expensive for large surfaces our challenges: • large ratio of the collection and photocathode areas with minimal image distortion ratio = 7.3 achieved LENS SYSTEM, critical design • make use of the UV range fused silica LENSES couple to a read-out system able to guarantee efficiency, high rate operation and to preserve time resolution
Performances Ch photons from physics event photons / ring (≈ 1) 65 time resolution <1ns ring (≈1) : 0.3 mrad 2 /K separation at ph> 55 GeV/c Excellent suppression of m-halo high rate capability: up to 100 kHz Ch photons from m-halo
Single photoelectron detection ~ 90 fC ~ 270 fC ~ 30 fC Hamamatsu R7600-03-M16 MAPMT pedestal bialkali photocathode, 18x18 mm2 active surface, 16 pixels UV extended glass window with borosilicate glass (200 – 700 nm) 1 multiplication stage less 1 e Wide dynamic range all these photoelectrons must be detected for good efficiency Hit multiplicity per event vs threshold Large flat region between cross-talk and detection losses region
MAPMT readout electronics MAD4 boards and Dreisam boards mounted close to the MAPMTs 144 DREISAM boards 576 16-channel PMT 9 CATCH 144 Roof boards 1152 MAD4 boards 144 gigabit optical fibres 36 HOT-CMC
Analog electronics: MAD4 boards + Roof board • Based on MAD4 chip: • pre-amplifier + shaper + comparator • Low noise: 5-7fC • Average PMT signal: 500 fC • Up to 1MHz/channel 7 fC
CMAD: the new front-end chip for RICH-MAPMT Chip designed to replace the older ASIC (MAD4) Key requirements: Preserve the compatibility with the existing read-out Gain optimized for MAPMT read-out 8 channels per chip Gain programmable channel by channel Threshold and baseline adjustable channel by channel (on board DACs) • . Hits rate > 5 MHz From 0.8 mm BiCMOS to 0.35 mm CMOS
CMAD versus MAD4 MAD4 4 channels fixed gain = 3.5 mV/fC baseline restorer: up to 1 MHz/channel CMAD 8 channels programmable gain channel by channel: from 0.4mV/fC to 1.2mV/fC in step of 0.08; additional 4x gain multiplication improved baseline restorer: able to cope with a rate > 5MHz/channel programmable threshold on each single programmable common channel threshold for 4 channels programmable baseline on each single ------------------- channel 10 bits threshold DAC on chip 8 bits threshold setting the full biasing circuit is incorporated on chip
CMAD:Channel overview out + out + VBL in in FE FE LVDS LVDS One shot One shot VTH out out - - b9 b7 DAC DAC b0 b0 b7 b9 DAC DAC b0 b0 From the 1th DAC Front-end building blocks • Variable gain preamp • shaper • baseline restorer
CMAD: some test results Preamplifier Linearity Gain Control Threshold and baseline settings (DACs test) Channel speed Channels equalization
CMAD: some test results Preamplifier Linearity
CMAD: some test results R=R feedback C=C feedback Cdigit = Rdigit Gain Control I
CMAD: some test results Gain Control II
CMAD: some test results Threshold and baseline settings (DACs test)
CMAD: some test results Threshold and baseline settings (DACs test) Channels equalization
CMAD: some test results Channel speed
CMAD: In production! CMAD Team M.Chiosso, O. Cobanoglu, P. Delaurenti, M. Brusa, G. Mazza, D. Panzieri, A. Rivetti
Thanks to many colleagues… the COMPASS Torino group Università di Torino – Dip. Di Fisica Generale A. Avogadro I.N.F.N – Sezione di Torino Raffaello GARFAGNINI Ivan GNESI Antonino GRASSO Angelo MAGGIORA Marco MAGGIORA Daniele PANZIERI Bakur PARSAMYAN Guido PIRAGINO Elena ROCCO Stefano SOSIO Maxim ALEKSEEV Antonio AMOROSO Ferruccio BALESTRA Raimondo BERTINI Maria P. BUSSA Michela CHIOSSO Marialaura COLANTONI Oleg Yu. DENISOV Andrea FERRERO
Torino group responsabilities in COMPASS collaboration Detectors Multiwire proportional chambers (MWPCs) Rich-Wall RICH electronics and mirrors MW1 electronics Physics Pion polarizability analysis (Primakov) L polarization analysis Drell-Yan physics at COMPASS (proposal) Hadron run coordination
New PID performances Kaons identification efficiency • PID efficiency studies based on kaons from decay of exclusive F (1020) • (Ch.threshold < pk < 60 GeV/c) Michela Chiosso 10th ICATPP 09/10/2007
New PID performances 2006 data efficiency vs θk Michela Chiosso 10th ICATPP 09/10/2007