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Ultra-fast differential front-end electronics. 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 .
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Ultra-fast differential front-end electronics • 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) • Front-end Electronics • preamplifier • preamplifiers & shapers & comparators • test system • cooling and grounding • Main requirements: • 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 • Impedance adaptation • Amplitude resolution • Time resolution • Noise cut Low Z Voltage source + Zo Z Rp - Low Z T Francis ANGHINOLFI ELEC-2005Electronics in High Energy PhysicsWinter 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
+ Rp Z - Detector 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) • Advantages: - excellent E resolution - friendly pulse shape analysis • Disadvantages: - channel-to-channel crosstalk - pile up above 40 k c.p.s. - sensitivity to e.m.c. FEE (Input stage) G. Pascovici, IKP-Cologne, FEE Meeting, Saclay, 04 Dec. 2008
+ Rp Z - Detector 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. • Advantages: - limited signal pile up - limited channel-to-channel crosstalk - low sensitivity to parasitic signals - good timing resolution • Disadvantages: - pour signal/noise ratio FEE (Input stage) 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. • Advantages: - limited signal pile up - limited channel-to-channel crosstalk - low sensitivity to parasitic signals - good timing resolution • Disadvantages: - pour signal/noise ratio Single ended structure
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)
Charge Sensitive Preamplifier • Active Integrator (“Charge Sensitive (Pre)Amplifier”) • 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, • sensitivityA(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: • 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 • miniature, SMD technology -3 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
AGATA Single & Dual Gain Core reworked frequency compensations internal network compensation Lead comp. (1. OpAmp) Cryostat wiring as part of the front-end electronics external network compensation - minimum Miller effect (min.) - lead compensation (min.) - lead-lag compensation (adj.) - dominant pole compensation (adj.)
LYCCA CSPs (32- channels) block diagram - basic structure Input:68x high density flat band cable (SE*GND) Output:32xDifferential 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 ~ 500ps, • expected tr~ 200ps !) • energy output tf~10 µs • (no P/Z cancellation) • high counting rates • timing > ~1 Mcps • 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 • BF861 (1,B,C); BF862; BF 889 • b) GaAs-FETs (E-pHEMT) • ATF-35143; ATF-55143; ATF-38143 • Idrain, Vdrain to optimize the • noise & bandwidth characteristics • (10-15 mA, 2-2.7 V, 20-30mW) Pulse generator: Tektronix PG502 modified (less than 700ps rise/fall time) Scope: Tektronix TDS 3032 (300 MHz, 2.5 GHz sampling) tr ~ 930 ps
jFET, FET, HEMT selection • a)jFET, FET • BF861 (1,B,C); BF862; BF 889 • b) GaAs-FETs (E-pHEMT) • ATF-35143; ATF-55143; ATF-38143 • Idrain, Vdrain to optimize the • noise & bandwidth characteristics • (10-15 mA, 2-2.7 V, 20-30mW) tr ~ 505 ps Pulse generator: Tektronix PG502 modified (less than 700ps rise/fall time) Scope: LeCroy 44Xs (400 Mhz, 2.5 GHz sampling) tr ~ 499 ps
jFET, FET, HEMT selection • a)jFET, FET • BF861 (1,B,C); BF862; BF 889 • b)GaAs-FETs (E-pHEMT) • ATF-35143; ATF-55143; ATF-38143 • Idrain, Vdrain to optimize the • noise & bandwidth characteristics • (10-15 mA, 2-2.7 V, 20-30mW) tf ~ 498 ps Pulse generator: Tektronix PG502 modified (less than 700ps rise/fall time) Scope: LeCroy 44Xs (400 Mhz, 2.5 GHz sampling) tf ~ 498 ps 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 flat band cable (SE*GND) Outputs: 16x [E] ch. - differential 100 Ohm*, 32E out of 68 x high density flat band cable (10µs) (a) Diff. Comp. CML, LV-PECL, LVDS (b) tf ~10ns* (opt. ~ 100ns) Outputs: 16x [T] ch. - differential 100 Ohm*, 32T out of 68x high density flat band cable x 16 channels 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 output Ch. 1 input Ch. 2 input Ch. 2 output Ch2- timing • Advantages: • very fast • compact, small size • low PS (450mW/ch) • Disadvantages: • power consumption in vacuum ? • motherboard architecture • impedance matching for UHF ? w. motherboard • cooling in vacuum (~ 2D structure) • no motherboard architecture • impedance matching for UHF • solution only for small number of channels, • distribution of infrastructure signals (PS, adj.) no motherboard
Sensitivity: A(t) ~100 mV/10 fC slope: • [ walk ] • dynamic range, • even for constant • rise/fall times • CFD, ELD (extrapolated • leading edge), ARC • correlated 2. channel [ jitter ] • intrinsic noise, • intrinsic jitter • noise distribution • bandwidth Timing jitter Intrinsic jitter Ratio: amplifier rise time/ collection time • intrinsic jitter • BW[Hz] bandwidth, Nd ~spectral density • noise dispersion • intrinsic time resolution M. Ciobanu et al, A FEE card comprising a high-gain amplifier and a fast discriminator for TOF measurements
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…