Status of the CARIOCA project
description
Transcript of Status of the CARIOCA project
LEB Conference, Stockholm 2001
Status of the CARIOCA projectStatus of the CARIOCA projectWalter BoniventoWalter Bonivento
CERN / INFN CagliariCERN / INFN Cagliarifor the LHCb collaborationfor the LHCb collaborationand the CERN MIC groupand the CERN MIC group
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The LHCb muon The LHCb muon detectordetector
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
LHCb muon detector: main task provide L0 trigger for b X
Five stations, M1 to M5; four radial regions, R1 to R4
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
Readout electronicsReadout electronicsfor MWPC:for MWPC:
a) detector architecture a) detector architecture
2mm gap, 1.5mm wire spacing
wire, cathode and combined readout
Main performance requirement: efficiency in 20ns >99%
2 bi-gap logically OR-ed (DIALOG chip)
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
Detector signal: current with fast (ns) rise, fall
Detector capacitance from 20pF to 200pF
One threshold for time stamping: time resolution from slewing effect
Readout electronicsReadout electronicsfor MWPC:for MWPC:
b) requirementsb) requirements
Optimum amplifier peaking time compromise between noise and slewing
5.1)(1nst
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
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.
Readout electronicsReadout electronicsfor MWPC:for MWPC:
b) requirementsb) requirements
Measurements on a prototype chamber performed with ahybrid 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
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
High rate: dead time
pulse width <50ns unipolar and tail cancellation
wire signals AC coupled with RLCdec= 100s
baseline shifts baseline restoration
Low cross-talk : Zin< 50
Readout electronicsReadout electronicsfor MWPC:for MWPC:
b) requirementsb) requirements
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
CARIOCACARIOCAProject overviewProject 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 preamp
tail
Cancels 1/ttail
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
CARIOCACARIOCAProject overviewProject overview
PROTOTYPE CHIPS: step by step approach
•2000: positive preamp+current discriminator +LVDS 4ch (1 analog ch.)
•2001: positive preamp+current discriminator +LVDS 14ch
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
CARIOCACARIOCAProject overviewProject 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.)
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The positive The positive preamplifier:preamplifier:
a) designa) designCurrent amplifier NMOS with current mode feedback; unipolar
feed
NN
CRgmgm
p 2321 Dominant pole at about 20MHz, the other two at
150MHz and 300MHz
Large input transistor W/L=1600m/0.7mId=2mA
6I
I
3
4
IN
OUT N
N
gmgm
Followed by current discriminator (presented at LEB2000 by D.Moraes and replaced by a voltage discriminator in next version) +LVDS driver
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The positive The positive preamplifier:preamplifier:
b) measurementsb) measurements
Response to a delta Linearity...and analog measurements
Sensitivity: 8mV/fC (measurement)
Digital (S-curve)...
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The positive The positive preamplifier:preamplifier:
b) measurementsb) measurements
Threshold vs.Cd
Response to a delta
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
Simulation (CADENCE)
Analog measurementDigital measurement
Noise vs. Cd
ENC = 867e- + 36e-/pF
calculation from noise theory
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The positive The positive preamplifier:preamplifier:
b) measurementsb) measurementsProblems 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
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The negative The negative preamplifier:preamplifier:
a) designa) design
N2,N3,N4 replaced by PMOS
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The negative and The negative and positive preamp:positive preamp:
frequency responsefrequency response negative positive
Input impedance: below 50
3dB level is at:• 16 MHz for negative• 23 MHz for positive
CADENCE simulation
Closed loop gain
Cdet=60pF
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The negative The negative preamplifier:preamplifier:
b) measurementsb) measurementsResponse to a delta
Linearity
Cd=100pFCd=15pF
MeasurementsSimulation
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
Peaking time vs. Cdimproved w.r.t firstprototype
Sensitivity vs. Cd
The negative The negative preamplifier:preamplifier:
b) measurementsb) measurements
Noise vs. Cd
Response to a delta
ENC= 951e- + 31e-/pF
MeasurementsSimulation
Channel uniformity of noise and threshold: 7% r.m.s.
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The negative The negative preamplifier:preamplifier:
b) measurementsb) measurements
Response to a quasi 1/t pulse
Cd=15pF
Cd=100pFquasi 1/t injector
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The shaper:The shaper:a) designa) design
Designed for 1ns peaking time (not to add to the preamp)
Folded cascode fully differential balanced (CMF)
Dominant pole (neglecting p.z. comp)at 160MHz
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The shaper:The shaper:a) design a) design
snnsnsns
ss
ss
405.3809
/1/1
/1/1
42
31
4
3
2
1
Cdet=60pF
• 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)
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The shaper:The shaper:b) measurementsb) measurements
Response to a delta: single ended ouptut (true output will be differential)
Cd=15pF Cd=100pF
This prototype chip with the positive preamplifier
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The shaper:The shaper:b) measurementsb) measurements
Response to a delta: single ended output (true output will be differential). Saturation current on ( ) and off ( )
Linearity: improved with saturation current ON (changes the DC level at the drain of N0)
MeasurementsSimulation
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The shaper:The shaper:b) measurementsb) measurements
Response to a delta: single ended output (true output will be differential). Saturation current on.
Cd=15pF
Cd=100pF
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The shaper:The shaper:b) measurementsb) measurements
Noise vs. Cd
Sensitivity vs. Cd
Response to a delta: single ended output
ENC= 1290e- + 40e-/pFwith saturation current ON
MeasurementsSimulation
Parallel noise term higher thanpreamp alone due to twopreamplifiers at shaper input
Peaking time vs. Cd.Faster than negative consistent with different bandwidth
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The shaper:The shaper:b) measurementsb) measurements
Response to a quasi 1/t pulse
Cd=15pF
Cd=100pF
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
The shaper:The shaper:b) measurementsb) measurements
Peaking time vs. Cd
Sensitivity vs. Cd
Pulse width vs. Cd
Response to a quasi 1/t pulse
MeasurementsSimulation
LEB Stockholm 2001
W.Bonivento CERN/INFN Cagliari
Conclusions and Conclusions and perspectivesperspectives
• Amplifier+shaper+Voltage discriminator chip (following ATLAS MDT chip design) under test • +Baseline restoration chip under design
Negative preamplifier and positive preamplifier with shaperchips tested and satisfying the requirements for LHCb operation
LEB Conference, Stockholm 2001
THE ENDTHE END