TileCal Electronics A Status Report J. Pilcher 17-Sept-1998

17-Sept-98 Outline A status report on the front-end and digitizing electronics Overview of requirements Development status July ’98 test beam results  Barrel module 0 equipped with 2 superdrawers –90 channels  First system tests with “in-drawer” digitizers

17-Sept-98 REQUIREMENTS Process 10,000 PMT signals Located in 256 electronics drawers Up to 45 PMT/drawer Each module self-contained with own electronics

17-Sept-98 REQUIREMENTS Performance 16 bit dynamic range  Up to 2 TeV in single cell  Must see muons –Calibration and monitoring –Enhance muon ID Readout resolution should not degrade calorimeter energy resolution  Calorimeter resolution > ~2%  Need readout resolution of a few percent in each cell  Jet populates many channels –averaging effects

17-Sept-98 REQUIREMENTS In situ calibration Gives readout conversion factor (pC/count) Measures linearity Calibrates source integrator  Slow integrator for PMT current LVL1 trigger tower sums

17-Sept-98 ORGANIZATION 3-in-1 Card One per PMT Plugs into PMT anode  Near-ideal current source Pulse shaped signals to digitizers Integrator for source calibration and monitoring min-bias current  Gain switching  Output gating Charge injection for electronics calibration LVL1 Trigger output  Gated

17-Sept-98 ORGANIZATION Mother Boards set of 4 in tandem per drawer Services and control signals to 3-in-1 Digitizer Boards set of 4 (or 8) per drawer Connections to drawer TTC fiber S-LINK fiber D.C. Power CANbus

17-Sept-98 Bigain pulse shaper 7-pole Bessel filter (purely passive)  Exploit current source nature of PMT  No noise, no power  Very linear Clamping amplifiers and drivers  Gain ratio 64:1 for dual 10-bit ADCs 3-in-1 Card Status

17-Sept-98 Output pulse to digitizers Low Gain (1 GeV/mV)  Full scale signal High Gain (16 MeV/mV)  Muon signal 3-in-1 Card Status

17-Sept-98 Linearity and calibration Residuals < 1 count over full dynamic range 3-in-1 Card Status ±1 count

17-Sept-98 Source integrator Essential for Cs calibration and monitoring of calorimeter  See preceding talk Cs calibration has short-term reproducibility of ~ 0.1%  Should be matched by electronics stability 3-in-1 Card Status

17-Sept-98 independent readout for each drawer ADC board + CANbus  Multiplexed to individual 3-in-1 cards Integrator Readout Status

17-Sept-98 Source Integrator Stability better than 0.1% over 2 months (calibrator + integrator)

17-Sept-98 Digitizer Status Partially equipped Barrel Module 0 (30 channels) in July ’98 First system test of “in-drawer” digitizers Two 10-bit 40 MSPS ADCs per channel High gain scale GeV (16 MeV/count) Low gain scale GeV (1 GeV/count) Commercial components TTC input on optical fiber 40 MHz clock, LVL1 accept, digitizer control data

17-Sept-98 Digitizer Status Pipeline delay via custom ASIC Digital memory unit (DMU) Originally developed for PHENIX TEC Output via optical S-LINK Read with optical LDC/PMC, RIO processor

17-Sept-98 July ’98 Test Beam Results Laser calibration Measure linearity and stability of PMT and electronics  3 PIN diodes to monitor laser

17-Sept-98 July ’98 Test Beam Results Digitized signals More pedestal noise on high gain channel Digitizing clock not synchronized to beam

17-Sept-98 July ’98 Test Beam Results Pedestal Noise Noise for high gain branch ~ 1.1 counts  Corresponds to ~ 0.4 photoelectrons in PMT (17 MeV)  SPICE simulation predicts 1.2 counts Noise for low gain branch ~0.5 counts  SPICE simulation of 3-in-1 card predicts 0.3 counts  Digital noise < ~ 0.4 counts

17-Sept-98 July ’98 Test Beam Results Muon response for the 3 sampling depths (  =90  ) Pedestal superimposed  Using “signal” from empty events  Width reflects energy algorithm as well as electronics –10 digitizations used for each measurement (not optimized) Muon signal well resolved from pedestal

17-Sept-98 July ’98 Test Beam Results Electron response Most energy in a single cell Channel-to-channel intercalibration less important  Calibration not yet available 50 GeV and 100 GeV electrons

17-Sept-98 July ’98 Test Beam Results Use e - response to measure readout resolution Fit for a reflects readout resolution and energy algorithm

17-Sept-98 Energy resolution gives readout resolution of 0.5 counts/sample ADC quantization error  noise ... Noise study gave 0.5 counts Well understood result Readout will not limit resolution of hadronic calorimeter July ’98 Test Beam Results

17-Sept-98 July ’98 Test Beam Results Pion energy resolution from test beam Under analysis Needs cell-to-cell intercalibration  Electron shower largely contained in single cell

17-Sept-98 Future Planning Radiation hardness tests this fall Design review this fall Electronics PRR spring ’99 3-in-1 production to start spring ’99 Version 2 of digitizer to be demonstrated spring ’99 Final electronics needed for module calibration in ’00, ’01, ’02 Finish production of electronics in ’02 Before start of installation

17-Sept-98 Conclusions TileCal electronics shows good performance Achieved required dynamic range with linear system  Very low system noise Electron energy resolution used to measure readout resolution First successful tests of “in-drawer” digitizers No unexpected problems so far Still a lot of work to do! Expect to start production on schedule