1. Hold signal Variable Gain Preamp. Variable Slow Shaper S&H Bipolar Fast Shaper 64Trigger outputs Gain correction (6 bits/channel) discriminator threshold 10 bit DAC Multiplexed charge output MAROC : Multi-Anode Read-Out Chip ATLAS luminometer : Roman pots detectors used to calibrate absolute luminosity 10 staggered planes of 2x64 0.5 mm2 fibers (in UV configuration with 50 µm layer offset) 1 roman pot = 10*64 fibers in U + 10*64 fibers in V Readout with multi-anode PMT64, Hamamatsu H7546 PM gain : 3.10 5 to 10 6 MIP signal = 4-6 photoelectrons Variable differential CRRC2 shaper tp = 50-200 ns Fast differential CRRC shapers tp=20-200ns Track and Hold + Widlar buffer + 5 MHz MUX Low offset comparator Variable gain Preamplifier (G=0-4) “Super common base” current conveyor Trigger output Fast shaper : Peaking time tp = 15ns High gain : 3 V/pC Noise ~ 1 mV Pedestal spread : 2.2 mV rms Comparator : Differential bipolar pair Offset spread : ±1 mV Speed < 5 ns GTL output (0.6-1V) Trigger efficiency : 50% trigger at 50 fC @G=1 dispersion 4fC rms noise 1 fC crosstalk < 1% i in i out Preamplifiers “Super common base” input : Low input impedance (~50-100Ω) (tunable) Low bias current (20 µA) Low noise : e n = 2 nV/√Hz Current mirror : Scaled : 2, 1, 1/2, 1/4, 1/8, 1/16 (6 bits) Range : 0 to ~ 4 Linearity : ± 1 %  Technology: AMS SiGe 0.35µm  Chip area : 12 mm 2  Package : QFP100  Power consumption : 130 mW (2mW/channel)  submitted july 2005 chip requirements 64 low impedance (100Ω) inputs variable gain preamplifiers 0-4 to correct PM non uniformity (6 bits/channel) 64 discriminator outputs, threshold at 0.3 p.e. (50 fC) loaded by 10 bit DAC 1 multiplexed charge output with 20-200 ns variable shaping (max 5pC=30p.e.) Trigger at < 0.3 p.e. ± 0.1p.e. Dynamic range : 11 bits : Qmax = 5 pC, noise = 2 fC Linearity ~ 2% crosstalk < 1% 200 chips to be produced in 2007 Charge output Slow shaper : Sallen-Key CRRC 2 Peaking time t p = 20-200 ns Gain : 150 mV/pC (25 mV/p.e.) 1V max output Noise ~ 500 µV rms Pedestal spread : 3 mV rms Track & Hold : 2 pF storage capacitor Widlar differential buffer Readout speed : 5 MHz  preamp schematic Pierre BARRILLON, Sylvie BLIN,, Christophe de LA TAILLE, Patrick PUZO, Nathalie SEGUIN-MOREAU IN2P3/ LAL Orsay France RP IP 240m RP 10x MAPMTs MAPMT FE Mother board HV LV TTC Trigger Data Substrate coupling : Substrate resistance (~20Ω) couples mirror output to preamp ground return  oscillations for ground inductance > 20nH  chip on board mounting mandatory  will be alleviated by substrate separation MARO C ASIC 64ch PM socket USB port GPIB port Control Altera Hold signal Photomultiplicer 64 channels Photons Variable Gain Preamp. Variable Slow Shaper 20-100 ns S&H Bipolar Fast Shaper Unipolar Fast Shaper Gain correction 64*6bits 3 discriminator thresholds (3*12 bits) Multiplexed Analog charge output LUCID S&H 3 DACs 12 bits 80 MHz encoder 64 Wilkinson 12 bit ADC 64 trigger outputs Multiplexed Digital charge output MAROC2 : substrate separation unipolar fast shaper for counting rate up to 50MHz 3 discriminators/ch 80 MHz encoding 12bit Wilkinson ADC/ch submitted march 06 Vin= 1V AC vss1vss 2 R Cd 10 pF Variable I mirrors -200 dB -100 dB 0 dB Q1 SBC Vout= 1Ω*Iout Chip on baord MAROC ASIC PMF board = PMT + electronics in the shadow of PM ©B. Lundberg 64 PM inputs 10 bit DAC Chip on b64 ch multi-anode photomulitiplier PM gain dispersion Non uniformity : 1 to 3 Trigger efficiency vs channel number (“s curves”) 50% trigger efficiency vs channel number (G=1) average = 50 fC = 1/3 phtoelectron Crosstalk : up to 10 pC injected in channel 34, trigger at 50 fC, 2 direct neighbours trigeer at > Trigger efficiency for different preamp gains Signal waveforms for different preamp gainsLinearity vs preamp gain (0 to 4) Output waveforms for 0 to 5 pC input Pedestal dispersion Substrate resistance 10 bit DAC for common threshold MAROC Chip-On-Board testboard Roman pots with scintillating fibers for luminosity measurement ©CERN Readout electronics mounted on roman pots : 5x5 PM array ©CERN, Lund Substrate coupling modelization in preamp ground Synoptic diagramm of MAROC2 chip