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La nuova elettronica di front-end La nuova elettronica di front-end per il rivelatore RICH di COMPASSper il rivelatore RICH di COMPASS
Michela Chiosso Università di Torino – Dip. di Fisica Generale
INFN – Sezione di Torino
1th Congressino di DipartimentoDip. di Fisica Generale A. Avogadro, 7- 8 Aprile 2008
OutlineOutline
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 experimentThe COMPASS experimentCOmmon Muon Proton Apparatus for Structure and Spectroskopy
270 physicists, 25 institutes, 11 countries270 physicists, 25 institutes, 11 countries
nucleon structure measurements hadron spectroscopy measurements
The COMPASS spectrometerThe COMPASS spectrometerCOmmon Muon Proton Apparatus for Structure and Spectroskopy
Cherenkov EffectCherenkov Effect
cos c = n
Partice
lla ca
rica
Rich detector: a cherenkov counterRich detector: a cherenkov counter
The ingredients:The ingredients:
1. Radiator2. Light collector3. Large area photon detectors
0n
1Cthr
1n
1arccosmax
C
c2
2
22
sinz2
dxd
Nd
..
..
ep
ep
N
minimizing p.e
maximizing Np.e.
Cherenkov Light Imaging Technique:Cherenkov Light Imaging Technique:
the first paperthe first paper
.. . . .... . ..
RICHRICH
RRing ing IImage mage ChCherenkoverenkov
Gaseous radiator; image focusing by spherical or parabolic mirrors
1977 Ypsilantis & Seguinot1977 Ypsilantis & Seguinot
COMPASS RICH COMPASS RICH gaseous radiator gaseous radiator
Particle IdentificationParticle Identification
COMPASS RICHCOMPASS RICH
RadiatorRadiator
12 MWPC with CsI photocathodes 4 camera with multianode photomultipliers
Photon-detectorsPhoton-detectors
2 spherical mirrors:
total surface = 21m2
Angular acceptance: ± 250 mrad horizontal; ± 180 mrad vertical
Light collectorLight collector
C4F10 transmittance > 80% (=165 nm) n=1.0015
The photon detectorsThe photon detectors
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
MWPCs with CsI Photocathodes (already in use since 2001)
spherical surface
aspherical surface
planar surface
MAPMT
CsI MWPC
MaPMTOutsideOutside
MAD4 + F1
A photon-detector view…A photon-detector view…InsideInside
Phast photo-detection systemPhast 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
PerformancePerformancess
photons / ring (photons / ring (≈ 1) 65≈ 1) 65
time resolution <1nstime resolution <1ns ring ring ( ≈≈1) : 0.3 mrad
2 /K separation at ph> 55 GeV/c
Excellent suppression of Excellent suppression of -halo-halo
high rate capability: up to 100 kHzhigh rate capability: up to 100 kHz
Ch photons fromphysics event
Ch photons from-halo
Single photoelectron Single photoelectron detectiondetection
Wide dynamic range
pedestal
1 multiplication stage less
1 e
all these photoelectrons must be detected for good efficiency
~ 270 fC~ 30 fC ~ 90 fC
Hit multiplicity per event vs threshold
Large flat region between cross-talk and detection losses region
bialkali photocathode, 18x18 mm2 active surface, 16 pixels
UV extended glass window with borosilicate glass (200 – 700 nm)
Hamamatsu Hamamatsu R7600-03-M16 MAPMTR7600-03-M16 MAPMT
144 DREISAM boards
36 HOT-CMC
9 CATCH
144 gigabit optical fibres
1152 MAD4 boards
144 Roofboards
57616-channelPMT
MAD4 boards and Dreisam boards mounted close to the MAPMTs
MAPMT readout MAPMT readout electronicselectronics
Readout electronics of 1 Readout electronics of 1 quarterquarter
Analog electronics:Analog electronics: MAD4 boards + Roof MAD4 boards + Roof
boardboard 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 CMAD: the new front-end chip forfor
RICH-MAPMT RICH-MAPMT
.
Preserve the compatibility with the existing read-out
Chip designed to replace the older ASIC (MAD4)Chip designed to replace the older ASIC (MAD4)
Key requirements:Key requirements:
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 m BiCMOS
to 0.35 m CMOS
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 commonchannel 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 versus MAD4CMAD versus MAD4
MAD4
4 channels
fixed gain = 3.5 mV/fC
baseline restorer:up to 1 MHz/channel
CMAD:CMAD: Channel overviewChannel overview
FE
DAC b0
b7
One shot LVDSin out +
out -
FE
DAC b0
b9
One shot LVDSin out +
out -
DAC b0
b7
DAC b0
b9
VBL
VTH
PreampOTA
BLHVref_blh
-
+Vref_OTA
inVout
PreampOTA
BLHVref_blh
-
+Vref_OTA
inVout
From the 1th DAC
Variable gain preamp shaper baseline restorer
Front-end building blocksFront-end building blocks
CMAD: some test resultsCMAD: some test results
PreamplifierPreamplifier LinearityLinearity
Gain ControlGain Control
Threshold and baseline Threshold and baseline settingssettings
(DACs test)(DACs test)
Channels equalizationChannels equalizationChannel speedChannel speed
CMAD: some test resultsCMAD: some test results
PreamplifierPreamplifier LinearityLinearity
CMAD: some test resultsCMAD: some test results
Gain Control IGain Control I
R=R feedbackC=C feedback
Cdigit = Rdigit
CMAD: some test resultsCMAD: some test results
Gain Control IIGain Control II
CMAD: some test resultsCMAD: some test results Threshold and baseline Threshold and baseline
settingssettings(DACs test)(DACs test)
CMAD: some test resultsCMAD: some test results Threshold and baseline Threshold and baseline
settingssettings(DACs test)(DACs test)
Channels equalizationChannels equalization
CMAD: some test resultsCMAD: some test results
Channel speedChannel speed
CMAD: In production!CMAD: In production!
M.Chiosso, O. Cobanoglu, P. Delaurenti, M. Brusa, G. Mazza, D. Panzieri, A.
Rivetti
CMAD TeamCMAD Team
Thanks to many colleagues… Thanks to many colleagues… the COMPASS Torino groupthe COMPASS Torino group
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
Università di Torino – Dip. Di Fisica Generale A. AvogadroI.N.F.N – Sezione di Torino
Torino group responsabilities in COMPASSTorino group responsabilities in COMPASScollaborationcollaboration
Multiwire proportional chambers (MWPCs)
Rich-Wall
RICH electronics and mirrors
MW1 electronics
DetectorsDetectors
Pion polarizability analysis (Primakov)
polarization analysis
Drell-Yan physics at COMPASS (proposal)
Hadron run coordination
PhysicsPhysics
Spare Slides
New PID performances
Michela Chiosso 10th ICATPP 09/10/2007
Kaons identification efficiency
PID efficiency studies based on kaons from decay of exclusive Ch.threshold < pk < 60 GeV/c)
New PID performances
Michela Chiosso 10th ICATPP 09/10/2007
efficiency vs θk
2006 data
10 bit DAC10 bit DAC