V. Korbel, DESYECFA-DESY Workshop, NIKHEF1 Readout for the minical and Tile-HCAL prototype, 15’ The VFE RO: The light signals Photo-detectors 1) APD’s (Hamamatsu, ) 2) Si-PM’s (MEPhI) 3) MA-PMs(Hamamatsu) 4) MRS-APD’s(Obninsk) Preamplifiers, shaper charge sensitive (ECAL-LAL, Minsk) voltage sensitive (Prague) the electrical signals 0-3Volt range, dyn. range 1-75 (100) MIPs/cell ns rise 150 ns (95%) buffering and multiplexing digitising calibration and monitoring minical : pre-prototype Tile-HCAL The different photodetectors front end electronics (VFE) time schedule, needs event format and DAQ (P.Daucey)

V. Korbel, DESYECFA-DESY Workshop, NIKHEF2 The light signals produced number of photons by MIP: ~ 150 ph/MIP/tile, loss in fibre-RO: ~20%, tile; = 1/3 cell 1 (absorber plate+tile) deposes ~24 MeV >> in a cell ~ 72 MeV maximal energy deposit/cell ~ 4.5 GeV (in rare tails) ratio maximum/MIP = 65

V. Korbel, DESYECFA-DESY Workshop, NIKHEF3 The photodetectors receive the light from the scintillator tiles of the sampling calorimeter. options studied are: -Si-APD's, with 3x3 to 4x4 mm 2 photo-cathodes, in arrays of individuals or matrix assembly, as in study at Hamamatsu, Japan and -Si-PM's, with 1x1 to 2x2 mm 2 photo-cathode, from MEPhI/PULSAR(Moscow), 576 >>> 1000 pix/mm 2 All systems are in still in development, no dedicated choice can be made at present. The photodetectors

V. Korbel, DESYECFA-DESY Workshop, NIKHEF4 Required gain for pre-amps, 2 options A) for APD’s: 150 photons/tile = 450 photons/cell, ~80% transmission, 80% photo-conversion efficiency: possible intrinsic gain ~ (to be verified) >>> e - / MIP= fC/cell conventional stable intrinsic gain ~ >>> e - / MIP= fC/cell slope/width of photodetector signal: ~ 2-5ns/20-30 ns width required dynamic range: 65! If MIP in cell channel 16 >>> 4.5 GeV: channel 3000, 12 bit ADC, ch 4096 = 3 V and >>>> ch 16 =12 mV preamp gain required: 12 mV/7.2 fC = 1.7 mV/fC 12 mV/1.8 fC = 6.8 mV/fC Resolution: 10 bit ADC: -4.5 MeV/bin 12 bit ADC, -optimal in range: ~ 1 MeV/bin

V. Korbel, DESYECFA-DESY Workshop, NIKHEF5 Required gain for preamps, 2 options B) For the Si-PM's: much less preamp gain is needed SiPM intrinsic gain is ~10 6 a VFE RO-board development is under way at MEPhI and PULSAR (both Moscow), based on the H1-PM preamps. They also look in an alternative pre-amp/shaper concept. more on the photodetectors and pre-amps can be found in: and....../DESY-Zeuthen_ pdf.

V. Korbel, DESYECFA-DESY Workshop, NIKHEF6 more on preamplifiers for APD’s CALICE-ECAL: prototype: ~10 mm 2 preamp chip, modified OPERA type for APD modifications specified and simulated in chip, design ready next week submission of modified design for prototypes 25 x18 ch. delivery in June Use in minical Summer 2003 Minsk/Protvino: 2 types tested with APD and MIP’s 10 preamps available 100 preamps in February 2003, design of 16 channel MPC prototype: (~ 8000 Euro needed??) Prague (I.Polak): voltage amplifier, (probably not optimal for APD’s??), signals seen in DESY test, signal/noise??? agreed to produce 16 channels PT end Febr development financed by Prague DESY trans-impedance type, tested with APD’s, mod. CMS-type, cheap !, P. Smirnov Test of all oreamps from above in minical tests when available in time. Decision on what to use in preprototype: October 2003

V. Korbel, DESYECFA-DESY Workshop, NIKHEF7 Electrical signals from the minical Noise, randoms cosmics LED-pulses CAMAC Read-Out, LC-2249A MA-PM as photodetector now up to 144 channels needed in summer 81 Si-PMs 27 APDs 3 MA-PMs (up to 48 channels)

V. Korbel, DESYECFA-DESY Workshop, NIKHEF8 More on photodetectors Hamamatsu,multianode PM,4  4mm 2 pixel Hamamatsu,APD, 5  5 mm 2 Hamamatsu,APD-array,1  1 mm 2 pixel MEPHI, Si-PM, 1  1 mm 2 pixel Detailed investigation of available photodetectors with 5  5 cm 2 scintillator tiles in test beams MIP peaks clearly separated from pedestals. satisfactory performance none yet tested in high field all will be used in minical to establish performance and get operation experience than decision which to use!! V sensitive pre-amp, Prague pre-amp from MEPhI PM pre-amp, DESY-H1 Q sensitive pre-amp, Minsk

V. Korbel, DESYECFA-DESY Workshop, NIKHEF9 The VFE-ROB-scheme Array of Photo detectors pulse shapers Sample & hold Multi plexer (analog) Trigger/ RO clock LED signals PIN diode for LED monitoring HV for Photo detectors sensitive preamps pedestals Online Gain/HV monitoring? cosmic beam

V. Korbel, DESYECFA-DESY Workshop, NIKHEF10 The Read-Out Boards (VFE-ROB’s) for prototype It is foreseen to place the photodetectors on the surface of a ROB (read-out board), as tight together as possible, on special sockets to be developed, about 108 (6 x 18) pieces on one board. For the Si-PMs probably 3-4 times more have to be placed on a ROB. About ROB's are needed for the Tile_HCAL prototype end ( ??? channels) The signals from the pre-amps, which have to deliver signals of 8mV/fC input charge, have to be shaped (shaping time ~ ns) and stored in sample and hold (S&H) pipelines for a time period of about 1-2 msec. Than a multiplexed read-out, clocked by the DAQ, will empty the pipelines.

V. Korbel, DESYECFA-DESY Workshop, NIKHEF11 Calibration on VFE-ROB’s Cosmic muon calibration: the FE boards should be permanently operational to allow, between test-beam pulses, continuos collection of the low rate cosmic muons penetrating the calorimeter, which are used for real time on-line calibration. They generate their own calibration triggers. Low rate process, for precise calibration of whole chain Preamp calibration: by charge injection, >> dynamic range linearity, high rate process, tests electronic chain only

V. Korbel, DESYECFA-DESY Workshop, NIKHEF12 Electronic calibration Polarisation (-200V) Diode Déclenchement Calibrage Chip VFE I calib LR C injection 6 circuits de calibrage opérant sur 18 diodes chacun Le premier PCB du prototype physique Studies with CALICE-ECAL chip

V. Korbel, DESYECFA-DESY Workshop, NIKHEF13 Photodetector monitoring on VFE-ROB’s LED monitoring: The ROB should also integrate a few light emitting diodes (LED's) with LED-light distribution by clear optical fibres. to all individual photodetectors for stability monitoring, and also to a few stable Si-photodiodes (stable against temperature and bias voltage fluctuations) to monitor the LED light output. The analogue signals of the LED monitoring photodiodes and the Si-PD’s (some?) have also to be amplified, shaped and stored in the same S&H pipeline. LED monitoring has to be triggered in the gaps between the test-beam pulses and during the read-out!

V. Korbel, DESYECFA-DESY Workshop, NIKHEF14 More on VFE-ROB duties The ROB has to integrate the active elements (chips, to be developed) and in tight package all the signal lines up to the S&H and multiplexer, the power lines for the individual photodetectors (~400V for the APD's, or ~30V for the Si-PM's), where each photodetectors operation voltage will be adjusted individually for equal gain on the level of ~0.1V. It is hoped, that we can profit considerably from the design of the ROB prototypes of the CALICE-ECAL at LAL/Orsay. Group strongly interested in taking over VFE and DAQ duties: DUBNA: (I. Golutvin, I. Tyapkin)

V. Korbel, DESYECFA-DESY Workshop, NIKHEF15 On chip Amp Vdc = -200V OPA DC block Detector Charge preampshaperTrack & hold channel architecture, chip ECAL >> HCAL LAL-Oray, F. Richard,dela Taille, offered to us to modify the ECAL-preamp/shaper chip for the requirements of the Tile-HCAL APD’s >>>>>

V. Korbel, DESYECFA-DESY Workshop, NIKHEF16 FLC_HCAL pinout Charge inputs Voltage outputs MUX output Package : CQFP64 64 pins FLC_HCAL chip 1,7mm 2,5mm 25/03/03, LAL pre-amp layout

V. Korbel, DESYECFA-DESY Workshop, NIKHEF17 LAL/Orsay studies for Tile-HCAL pre-amps simulation studies for linearity Linearity preamp Linearity shaper/buffer

V. Korbel, DESYECFA-DESY Workshop, NIKHEF18 LAL/Orsay studies for Tile-HCAL pre-amps output signal shapes Output signal shaper Output signal preamp

V. Korbel, DESYECFA-DESY Workshop, NIKHEF19 18 charge inputs/18 voltage outputs/1 MUX output Gain= 6.7mV/fc  450 fC max input charge (70 MIP) 2.8V dynamic range below 1% non-linearity 25/03/03, LAL FLC_HCAL characteristics, next steps DESY will order 25 of such prototype chips at the 7.April 2003 >>> 25 x 18 =450 preamp channels delivered in mid June 2003 DESY gets test-board from LAL line driver prepared to run 30 channels for APD-minical studies (July-September 2003) If prototype chips are ok, we have enough channels to equip the APD-cells ( , to be decided in May) of the prototype calorimeter!

V. Korbel, DESYECFA-DESY Workshop, NIKHEF20 Draft of conclusions from the DUBNA meeting We need: ~ 1000 RO-channels at beginning of 2004 for the 1m 3 prototype test --APD’s (Hamamatsu) and Si-PM’s (MEPhI) will be used --photodetectors and preamps have to be optimised soon! --The size of APD’s will be ~3x3 mm 2 the gain required was specified, the combined gain of APD and preamp should result in 2-8 fC/MIP, the electronic noise should be below 4-5 sigma of MIP, the capacity of the APD’s will be ~ 25 pF, the stability of the MIP signal should be in the range of 1%, shaping time has to fit to the minimum bunch distance (180 ns), dynamic range required between MIP(4 bit) and max. signal is >/~65

V. Korbel, DESYECFA-DESY Workshop, NIKHEF21 Draft of conclusions from the DUBNA meeting Due to the short time available we probably have to proceed in 2 stages: 1. Use CALICE-ECAL VFE board with minimal modifications keep 108 channels/board keep ECAL preamps, noise,shaping,... modify implementation/arrangement of photodetectors on board modify photodetector power supply add LED monitoring for all channels Design a versatile VFE concept allowing use of different competing elements (preamps, HV distribution, monitoring..) 3. When useful VFE boards available for first 1000 channel tests: and more experience gained, (probably year later) implement optimal preamps (capacity, noise, gain), shaping optimise power supply and individual adjustment optimise online LED stabilisation

V. Korbel, DESYECFA-DESY Workshop, NIKHEF22 The VFE-ROB-scheme, APDs Array of single APDs or matrices pulse shapers Sample & hold Multi plexer (analog) Trigger/ RO clock LED signals PIN diode for LED monitoring HV, V dV/V~10 -4 charge sensitive preamps pedestals Online/Offline Gain/HV monitoring? cosmic beam Charge injection DAC