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