Status of the carioca project
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Status of the CARIOCA project. Walter Bonivento CERN / INFN Cagliari for the LHCb collaboration and the CERN MIC group. The LHCb muon detector. LHCb muon detector: main task provide L0 trigger for b   X Five stations, M1 to M5; four radial regions, R1 to R4.

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Status of the CARIOCA project

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Status of the carioca project

Status of the CARIOCA project

Walter Bonivento

CERN / INFN Cagliari

for the LHCb collaboration

and the CERN MIC group


The lhcb muon detector

The LHCb muon detector

LHCb muon detector: main task provide L0 trigger for b   X

Five stations, M1 to M5; four radial regions, R1 to R4

R3-R4 of M4-M5 RPC 48% area

rate cap. 1kHz/cm2

R1-R2 of M1 t.b.d. 1% area

rate cap. 1MHz/cm2

the rest MWPC 52% area

rate cap. 100kHz/cm2

W.Bonivento CERN/INFN Cagliari


Readout electronics for mwpc a detector architecture

Readout electronicsfor MWPC:a) detector architecture

Main performance requirement:

efficiency in 20ns >99%

2 bi-gap logically OR-ed

(DIALOG chip)

2mm gap, 1.5mm wire spacing

wire, cathode and combined readout

W.Bonivento CERN/INFN Cagliari


Readout electronics for mwpc b requirements

Readout electronicsfor MWPC:b) requirements

Detector signal: current with fast (ns) rise, fall

Detector capacitance from 20pF to 200pF

One threshold for time stamping: time resolution from slewing effect

Optimum amplifier peaking time

compromise between

noise and slewing

W.Bonivento CERN/INFN Cagliari


Readout electronics for mwpc b requirements1

Readout electronicsfor MWPC:b) requirements

Optimum amplifier peaking time: about 10ns

At large Cdet weak dependence of time resolution on peaking time

To be able to set the threshold at about 6 p.e.

Measurements on a prototype chamber performed with a

hybrid from PNPI and a modified version of ASDQ chip

(M.Newcomer-Penn)

noise <2fC for Cdet 40-250pF

At gas gain of 105

average 40fC for wires and 20fC for cathode

range 150fC for 95% of the signals

W.Bonivento CERN/INFN Cagliari


Readout electronics for mwpc b requirements2

Readout electronicsfor MWPC:b) requirements

High rate: dead time

pulse width <50ns

unipolar and tail cancellation

wire signals AC coupled with RLCdec= 100s

baseline shifts baseline restoration

Low cross-talk : Zin< 50 

W.Bonivento CERN/INFN Cagliari


Carioca project overview

CARIOCAProject overview

80k FE channels at 1Mrad dose in 10 years

custom chip in radiation tolerant technology 0.25 m CMOS

Final goal: differential structure

Cancels

1/t

tail

Cancels

preamp

tail

W.Bonivento CERN/INFN Cagliari


Carioca project overview1

CARIOCAProject overview

PROTOTYPE CHIPS: step by step approach

  • 2000: positive preamp+current discriminator

  • +LVDS 4ch (1 analog ch.)

  • 2001: positive preamp+current discriminator

  • +LVDS 14ch

W.Bonivento CERN/INFN Cagliari


Carioca project overview2

CARIOCAProject overview

  • 2001: negative preamp 8ch analog

  • 2001: positive preamp+shaper 4ch analog (diff. out.)

  • 2001: positive preamp+shaper+voltage discriminator+LVDS 4ch (diff. out.)

  • 2002: positive and negative full chain with baseline restorer (diff.out.)

W.Bonivento CERN/INFN Cagliari


The positive preamplifier a design

The positive preamplifier:a) design

Current amplifier NMOS with current mode feedback; unipolar

Large input transistor

W/L=1600m/0.7m

Id=2mA

at about 20MHz, the other two at

150MHz and 300MHz

Dominant pole

Followed by current discriminator (presented at LEB2000 by D.Moraes

and replaced by a voltage discriminator in next version) +LVDS driver

W.Bonivento CERN/INFN Cagliari


The positive preamplifier b measurements

The positive preamplifier:b) measurements

Digital (S-curve)...

...and analog measurements

Linearity

Response to a delta

Sensitivity: 8mV/fC (measurement)

W.Bonivento CERN/INFN Cagliari


The positive preamplifier b measurements1

The positive preamplifier:b) measurements

Response to a delta

Threshold

vs.Cd

Noise vs. Cd

ENC = 867e- + 36e-/pF

Channel uniformity of noise and threshold: 7% r.m.s.

Cross talk around 1%

Power consumption of about 18mW per channel dominated by

LVDS driver

Analog measurement

Digital measurement

Simulation (CADENCE)

calculation from noise

theory

W.Bonivento CERN/INFN Cagliari


The positive preamplifier b measurements2

The positive preamplifier:b) measurements

Problems of the discriminator:

1) it does not work below 10fC (need 5fC).

It was tested on a chamber prototype

efficiency plateau shifted by 100V w.r.t. to

our best measurement (with ASDQ chip).

2) it slows down the signal rise-time significantly (input C of discr.)

Peaking time

vs.Cd

7ns are expected from p.a. alone

Discriminator changed

in next versions of the chip

W.Bonivento CERN/INFN Cagliari


The negative preamplifier a design

The negative preamplifier:a) design

N2,N3,N4 replaced by PMOS

W.Bonivento CERN/INFN Cagliari


The negative and positive preamp frequency response

The negative and positive preamp:frequency response

negative

CADENCE simulation

positive

Closed loop gain

  • 3dB level is at:

  • 16 MHz for negative

  • 23 MHz for positive

Cdet=60pF

Input impedance: below 50

W.Bonivento CERN/INFN Cagliari


The negative preamplifier b measurements

The negative preamplifier:b) measurements

Response to a delta

Cd=15pF

Cd=100pF

Linearity

Measurements

Simulation

W.Bonivento CERN/INFN Cagliari


The negative preamplifier b measurements1

The negative preamplifier:b) measurements

Response to a delta

Peaking time vs. Cd

improved w.r.t first

prototype

Sensitivity vs. Cd

Noise vs. Cd

ENC= 951e- + 31e-/pF

Channel uniformity of noise and threshold: 7% r.m.s.

Measurements

Simulation

W.Bonivento CERN/INFN Cagliari


The negative preamplifier b measurements2

The negative preamplifier:b) measurements

Response to a quasi 1/t pulse

Cd=15pF

Cd=100pF

quasi 1/t injector

W.Bonivento CERN/INFN Cagliari


The shaper a design

The shaper:a) design

Folded cascode fully differential balanced (CMF)

Designed for 1ns peaking time (not to add to the preamp)

Dominant pole (neglecting p.z. comp)

at 160MHz

W.Bonivento CERN/INFN Cagliari


The shaper a design1

The shaper:a) design

  • 2-pole/zero network to compensate for the 1/t tail

  • basic idea from R.A.Boie et al.,NIM 192(1982)365

  • adapted to a differential amplifier design (M.Newcomer, Penn)

Cdet=60pF

W.Bonivento CERN/INFN Cagliari


The shaper b measurements

The shaper:b) measurements

This prototype chip with the positive preamplifier

Response to a delta: single ended ouptut (true output will be differential)

Cd=15pF

Cd=100pF

W.Bonivento CERN/INFN Cagliari


The shaper b measurements1

The shaper:b) measurements

Response to a delta: single ended output (true output will be differential). Saturation current on ( ) and off ( )

Measurements

Simulation

Linearity: improved with saturation current ON (changes the DC level at the drain of N0)

W.Bonivento CERN/INFN Cagliari


The shaper b measurements2

The shaper:b) measurements

Response to a delta: single ended output (true output will be differential). Saturation current on.

Cd=100pF

Cd=15pF

W.Bonivento CERN/INFN Cagliari


The shaper b measurements3

The shaper:b) measurements

Response to a delta: single ended output

Sensitivity vs. Cd

Peaking time vs. Cd.

Faster than negative

consistent with different

bandwidth

ENC= 1290e- + 40e-/pF

with saturation current ON

Noise vs. Cd

Parallel noise term higher than

preamp alone due to two

preamplifiers at shaper input

Measurements

Simulation

W.Bonivento CERN/INFN Cagliari


The shaper b measurements4

The shaper:b) measurements

Response to a quasi 1/t pulse

Cd=100pF

Cd=15pF

W.Bonivento CERN/INFN Cagliari


The shaper b measurements5

The shaper:b) measurements

Response to a quasi 1/t pulse

Peaking time vs. Cd

Measurements

Simulation

Sensitivity vs. Cd

Pulse width vs. Cd

W.Bonivento CERN/INFN Cagliari


Conclusions and perspectives

Conclusions and perspectives

Negative preamplifier and positive preamplifier with shaper

chips tested and satisfying the requirements for LHCb operation

  • Amplifier+shaper+Voltage discriminator chip (following ATLAS MDT chip design) under test

  • +Baseline restoration chip under design

W.Bonivento CERN/INFN Cagliari


The end

THE END


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