Download G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec - CEA-Irfu

Ultra-fast differential front-end
electronics
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Detectors as signal generators ~ Overview
Low Z vs High Z Front-End Electronics (FEE),
Differential vs. single ended FEE,
Preliminary design & measurements
G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
Front-end electronics – overview
Detector as a fast signal generator  electron-hole pairs collection
 only electrons (or particles)
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Front-end Electronics
preamplifier
preamplifiers & shapers & comparators
test system
cooling and grounding
Main requirements:
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gain (sensibility),
dynamic range (directly and/or ToT),
S/N,
rise/fall time and/or counting rates,
crosstalk, EMI, EMC,
power consumption etc.
G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
Detector Signal Collection
Circuit
High Z
Low Z
+
Rp
Voltage source
Zo
Z
-
• Impedance adaptation
• Amplitude resolution
• Time resolution
• Noise cut
Low Z
T
Francis ANGHINOLFI
ELEC-2005
Electronics in High Energy Physics
Winter Term: Introduction to electronics in HEP
Quo vadis ?
Low Z output voltage source circuit can drive any load
Output signal shape adapted to subsequent stage (ADC)
Signal shaping is used to reduce noise (unwanted fluctuations) vs. signal
Front-end electronics – overview
Detector as fast signal generator  electron-hole pairs collection
 only electrons (or particles)
if Z is high
charge is kept on capacitor nodes and voltage
builds up (until capacitor is discharged)
+
Rp
•
Z
- excellent E resolution
- friendly pulse shape analysis
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Detector
FEE
(Input stage)
Advantages:
Disadvantages:
- channel-to-channel crosstalk
- pile up above 40 k c.p.s.
- sensitivity to e.m.c.
G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
Front-end electronics – overview
Detector as fast signal generator  electron-hole pairs collection
 only electrons (or particles)
if Z is low
charge flows as a current through the impedance
in a short time.
+
Rp
•
Z
- limited signal pile up
- limited channel-to-channel crosstalk
- low sensitivity to parasitic signals
- good timing resolution
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Detector
FEE
(Input stage)
Advantages:
Disadvantages:
- pour signal/noise ratio
G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
MRCP detectors for LHC
Front-end electronics – overview
Detector as fast signal generator  electron-hole pairs collection
 only electrons (or particles)
if Z is low
charge flows as a current through the impedance
in a short time.
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Advantages:
- limited signal pile up
- limited channel-to-channel crosstalk
- low sensitivity to parasitic signals
- good timing resolution
Single ended structure
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Disadvantages:
- pour signal/noise ratio
Front-end electronics – overview
Specifications:
- Fully differential transimpedance
- 0.18µm standard CMOS techn.
- 10 GHz bandwidth
- dynamic range 25 µA -2.5 mA
- power consumption 88mW (2V)
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Charge Sensitive Preamplifier
Active Integrator (“Charge Sensitive (Pre)Amplifier”)
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Input impedance very high ( i.e. NO signal current flows into amplifier),
Cf (Rf) feedback capacitor (resistor) between output and input,
very large equivalent dynamic capacitance,
sensitivity A(q) ~ q / Cf,
large open loop gain Ao ~ 10,000 - 150,000
Ci ~ “dynamic” input capacitance
Rf
G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
Standard Charge Sensitive preamplifiers developed
at IKP Cologne et al.
Main achievements:
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low noise, fast preamplifiers (segmented HP-GE & DSSSD)
clean transfer function  pulse shape …(no over/under-shoots)
differential outputs for HP-Ge detectors & DSSSD-Si
high dynamic range
highly accurate spectroscopic TOT method (up to ~200MeV)
incorporated programmable pulser (50 ppm long term)
cryostat wiring (cold part), crosstalk less then 10 -3
miniature, SMD technology
Who are our main users?
- large arrays of segmented HP-Ge detectors :
Miniball (CERN), Rising (GSI), SeGa (MSU), Tigress (Triumf), AGATA (EU)
- DSSD Si detectors: LuSia (Lund,GSI), Miniball@IKP, LYCCA (GSI)…
G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
Miniball HeKo basic structure
Advantages:
- discrete electronic components
(e.g. HEMT, GaAs, SiGe)
- can be easily integrated,
- flexible open loop gain,
- frequency compensation vs.
detector unfriendly wiring
Disadvantages:
- to low open-loop gain
- larger size
G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
LYCCA CSPs
Charge Sensitive Loop - basic structure
Advantages:
- the use of advanced current
feedback operational amplifier,
- very fast,
- compact, small size, low PS
Disadvantages:
- to large open-loop gain,
- limited frequency compensation
vs. detector unfriendly wiring
G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
GALI -S66
(GSI)
G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
internal network
compensation
Miller
2x
D
N
reworked frequency compensations
G
AGATA Single & Dual Gain Core
Z
Lead comp.
(1. OpAmp)
L
D
N
L
C
- minimum Miller effect
(min.)
- lead compensation
(min.)
external network
compensation
C
C
C
Detector
AGATA
C
C
central
electrode
F
C
R,
G
F
i
R
C
Pole
j-FET
L
R
Dominant
C
D
N
G
Lead-lag
0
Cryostat wiring as part of the front-end electronics
- lead-lag compensation
(adj.)
segment
L
R,
L
R,
L
R,
L
R,
wiring
+
capsule
detector
AGATA
L
L
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1
Segment
preamplifiers
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R,
D
N
G
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2..35
Segment
R,
to
36
Segment
D
N
G
- dominant pole compensation (adj.)
LYCCA CSPs (32- channels)
block diagram - basic structure
Input: 68x high density
flat band cable (SE*GND)
Output: 32x Differential 100 Ohm*,
68x high density flat band cable
x 32 channels
G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
LYCCA - CSPs Transfer Function
a) energy channel (differential out.)
tr ~ 18 ns (Gain x1; Cd~10pF)
tr ~ 29 ns (Gain x3; Cd~10pF)
b) up-graded time channels
(also with differential outputs)
tr ~ 200 pS (tentative)
LYCCA CSPs
200 MeV & 4 GeV
32 channels only with
energy diff. outputs
or
16 channels with both,
energy and ultra fast
diff. outputs
mean
min
max
Sub - nanosecond CSP
• GaAs – HEMT
(Q1, Q2)
• ultra-fast, narrow
time output
(note: measured with
existing scopes: tr ~ 500 ps,
expected tr ~ 200ps !)
• energy output tf~10 µs
(no P/Z cancellation)
• high counting rates
timing > ~1 Mcps
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dominant pole
compensation included
low power, only +/- 6V E
+/- 3V T)
G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
LYCCA CSP modified for
fast timing outputs:
jFET: Bf861; BF862,
FET: BF988
HEMT: ATF-55143
Id ~ from 2mA – 10 mA
tr ~ 720 ps
jFET, FET, HEMT selection
a)
jFET, FET
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BF861 (1,B,C); BF862; BF 889
b)
GaAs-FETs (E-pHEMT)
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ATF-35143; ATF-55143; ATF-38143
c) Idrain, Vdrain  to optimize the
noise & bandwidth characteristics
(10-15 mA, 2-2.7 V, 20-30mW)
tr ~ 930 ps
Pulse generator:
Tektronix PG502 modified
(less than 700ps rise/fall time)
Scope:
Tektronix TDS 3032
(300 MHz, 2.5 GHz sampling)
jFET, FET, HEMT selection
tr ~ 505 ps
a)
jFET, FET
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BF861 (1,B,C); BF862; BF 889
b)
GaAs-FETs (E-pHEMT)
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ATF-35143; ATF-55143; ATF-38143
c) Idrain, Vdrain  to optimize the
noise & bandwidth characteristics
(10-15 mA, 2-2.7 V, 20-30mW)
Pulse generator:
tr ~ 499 ps
Tektronix PG502 modified
(less than 700ps rise/fall time)
Scope:
LeCroy 44Xs
(400 Mhz, 2.5 GHz sampling)
jFET, FET, HEMT selection
tf ~ 498 ps
a)
jFET, FET
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BF861 (1,B,C); BF862; BF 889
b)
GaAs-FETs (E-pHEMT)
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ATF-35143; ATF-55143; ATF-38143
c) Idrain, Vdrain  to optimize the
noise & bandwidth characteristics
(10-15 mA, 2-2.7 V, 20-30mW)
Pulse generator:
tf ~ 498 ps
Tektronix PG502 modified
(less than 700ps rise/fall time)
Scope:
LeCroy 44Xs
(400 Mhz, 2.5 GHz sampling)
G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
• Read-out from a
MCP + dual delay line based
position sensitive detector
• Two mutually perpendicular delay lines *
- Sobottka & Williams, IEEE Trans. NS
(1988),35, p348
- Kozulin, Kondratiev et al.,Nucl.Exp.Tech., 2008
No 58, p.44-58
Preliminary design - test measurements
Read-out from a MCP-based position sensitive detector
LT6411
• 3300V/µs
• 650 MHz
• 50-100 mW / ch.
G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
LYCCA CSPs (32- channels)
block diagram - basic structure
Input: 68x high density
flat band cable (SE*GND)
Outputs: 32x E - differential 100 Ohm*,
68x high density flat band cable
x 32 channels
G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
LYCCA like CSPs with implemented ultra-fast
differential time outputs – 16x channels
Input: 68x high density
Outputs: 16x [E] ch. - differential 100 Ohm*,
flat band cable (SE*GND)
32E out of 68 x high density flat band cable
(10µs)
(a) Diff. Comp.
CML, LV-PECL, LVDS
(b) tf ~10ns*
(opt. ~ 100ns)
x 16 channels
Outputs: 16x [T] ch. - differential 100 Ohm*,
32T out of 68x high density flat band cable
G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
To be decided: - with TOT ?
- with spectroscopic TOT ?
- differential signals standard: PECL, NECL, CML ?
To be decided: - with TOT ? And where ? On [E] or on [T] channel ?
- with spectroscopic TOT ? Or quasi spectroscopic?
- differential signals standard: PECL, NECL, CML ?
TOT circuitry?
- requirements has
to be decided ?
-E
or/and T
ch.?
GaAs(HEMT) +Transimpedance preamplifier-amplifier
~450 mW/ch
+ jFET
1 or 2 stages
GaAs(HEMT) +Si-Ge amplifier+ Si-Ge ultrafast comparator
~60 mW/ch
+ jFET
Potential solution with “motherboard”
LYCCA architecture (8 -16 channels)
Potential solution without “motherboard”
Input Output architecture (2 - 4 channels)
Ch1- timing
Ch. 1
input
Ch. 2
input
Ch2- timing
Advantages:
• very fast
• compact, small size
• low PS  (450mW/ch)
• cooling in vacuum (~ 2D structure)
• no motherboard architecture
• impedance matching for UHF
Ch. 1
output
Ch. 2
output
Disadvantages:
w. motherboard
no motherboard
- power consumption  in vacuum ?
- motherboard architecture
- impedance matching for UHF ?
• solution only for small number of channels,
• distribution of infrastructure signals (PS, adj.)
• Sensitivity: A(t) ~100 mV/10 fC
slope:
Timing jitter
[ walk ]
 dynamic range,
even for constant
rise/fall times
Intrinsic
jitter
Ratio: amplifier rise time/ collection time
M. Ciobanu et al, A FEE card comprising a high-gain
amplifier and a fast discriminator for TOF measurements
• CFD, ELD (extrapolated
leading edge), ARC
• correlated 2. channel
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[ jitter ]
 intrinsic noise,
 intrinsic jitter
• noise distribution
• bandwidth
intrinsic jitter
BW[Hz] bandwidth, Nd ~spectral density
noise dispersion
intrinsic time resolution
IE1I+IE2I
Electronic Design, Vol.46, No.25,1988
LVDS, CML differential interfaces
common-mode range compared to
single-ended noise margin.
The effective noise margin is 2 to 4
times better using LVDS, CML…