Nirmalya Parua March 25-29, 2002 The RunII D0 Calorimeter Electronics Upgrade & Its Performance Nirmalya Parua State University of New York Stony Brook Calor th International Conference on Calorimetry in High Energy Physics CalTech, Pasadena March 25-29, 2002

Nirmalya Parua March 25-29, 2002 Tevatron Run I ( ) Very successful Run I p-pbar collisions at √s = 1.8 TeV  L dt ~ 120 pb -1 delivered to DØ and CDF Peak luminosity ~ 1.6 x cm -2 s -1 Many exciting studies, including Top discovery M t =  5.2 (stat.)  4.9 (syst.) GeV/c 2  tt = 5.9  1.7 pb (DØ combined) W mass measurement M W = ± GeV (DØ combined) Limits on anomalous gauge couplings Limits on SUSY, LQ, compositeness, other exotica Tests of QCD + Electroweak b-quark physics 116 published papers >60 PhD theses

Nirmalya Parua March 25-29, 2002 Fermilab Accelerator Upgrade Two new machines at FNAL for Run II: Main Injector 150 GeV conventional proton accelerator Supports luminosity upgrade for the collider Recycler 8 GeV permanent magnet (monoenergetic) storage ring permits antiproton recycling from the collider Tevatron Status and Schedule 1.8 Tev  1.96 TeV Goal:  L dt = 2 fb -1 in Run 2a 15 fb -1 + in Run 2b Very first p-pbar collisions seen (August 2000) Main Injector (new) Tevatron DØCDF Chicago   p source Booster

Nirmalya Parua March 25-29, 2002 Bunch Structure 132 ns 0% 10% 20% 30% 40% # of Ints. / Crossing % Crossings 396 ns Detector readout and trigger system upgrade must take into account smaller bunch crossing time 3.56us 4.36us 2.64us superbunchgap 396ns gap used to form trigger and sample baselines Run I 6x6 Run II 36x36

Nirmalya Parua March 25-29, 2002 Overview of D0 Upgrade  Upgrade Calorimeter Readout  Add scintillator detector in muon system for faster trigger  Silicon and Fiber tracker with 2 Tesla solenoid magnetic field for central tracking and momentum measurement.  Add Pre-shower detectors.  Pipelined 3 Level trigger

Nirmalya Parua March 25-29, 2002 Calorimeter Overview L. Ar in gap 2.3 mm Ur absorber Cu pad readout on 0.5 mm G10 with resistive coat epoxy Liquid argon sampling Stable, uniform response, rad. hard, fine spatial seg. LAr purity important Uranium absorber (Cu or Steel for coarse hadronic) Compensating e/   1, dense  compact Uniform, hermetic with full coverage  < 4.2 (   2 o ),  int  total) Energy Resolution e:  E / E = 15% /  E  + 0.3%  :  E / E = 45% /  E + 4% Drift time 430 ns

Nirmalya Parua March 25-29, 2002 Intercryostat Detector (ICD)  Design  Scintillator based with phototube readout similar to Run I design. Re-use existing PMT’s (Hamamatsu R647).  16 supertile modules per cryostat with a total of 384 scintillator tiles  WLS fiber readout of scintillator tiles  Clear fiber light piping to region of low field ~40-50% signal loss over 5-6m fiber.  Readout/calibration scheme for electronics same as for L. Ar. Calorimeter but with adapted electronics and pulser shapes  LED pulsers used for PMT calibration  Relative yields measured > 20 p.e./m.i.p. Objectives Improve coverage for the region 1.1 < |  | < 1.4 Improves jet E T and E T Maintain the performance in the presence of a magnetic field ICD FPS

Nirmalya Parua March 25-29, 2002 Upgrade of Calorimeter Readout Objectives and Performance Criteria reduced minimum bunch spacing from 3.5  s to 396 ns (132 ns at RunII B). Storage of analog signal for 4  s for L1 trigger formation Generate trigger signals for calorimeter L1 trigger Maintain present level of noise performance and pile-up performance Methods Replace preamplifiers Replace shapers Add analog storage Replace calibration system Replace timing and control system Keep Run I ADCs, crates and most cabling to minimize cost and time

Nirmalya Parua March 25-29, ” FET driverpreamp Upgrade of Calorimeter Readout Bank 1 Preamp/ Driver Trig. sum Filter/ Shaper x1 x8 SCA (48 deep) Bank 0 Calorimeter Calibration 55k readout channels SCA(48 deep ) A n. B u f ADCADC 48 1 peak base Cable replaced for impedence matching

Nirmalya Parua March 25-29, 2002 Preamplifier FET 2” driverpreamp New calorimeter preamp Hybrid on ceramic 48 preamps on a motherboard New low-noise switching power supplies in steel box Dual FET Frontend Compensation for Det. Cap. Faster Recovery Time New output Driver for terminated signal 1152 boards hybrids

Nirmalya Parua March 25-29, 2002 Base Line Subtracter (BLS) ADC’s have 12 bit dynamic range. To achieve 15 bit dynamic range SCAs have low and high gain path for each readout channel (X8/X1) SCAs are not designed for simultaneous read/write operations. Two banks of SCAs, upper and lower (can’t see in the picture), for alternate read/write operation. Readout time ~6 µs (length of SCA buffers 132 X 46 >6 µs). Trigger tower formation 0.2 X 0.2 for Level 1. Trigger summers/Drivers 1152 BLS boards 4608 SCA cards SCAs Trig Summers

Nirmalya Parua March 25-29, 2002 T&C cards Timing and control CardTrigger system BLSADC Pulser Calorimeter Preamplifier  Receives trigger, accelerator, clock information  Samples BLS shapers at the signal peak and base.  Keeps track of the memory location of crossings.  Generates busy signal when system is not ready.  Coordinates pulser calibration. 12 T&C boards and 1 controller board is used

Nirmalya Parua March 25-29, 2002 Impedance Measurement PreAmp-Cryostat Cable Feedthrough various detector capacitances Broken cable Total 31 (<0.6%) are found

Nirmalya Parua March 25-29, 2002 Debugging and Noise Presently we have very few bad readout channels (<0.1%) Shows the level of Noise We are using 2.5*  as the zero suppression limit while taking data. Fine Tuning this limit is underway.

Nirmalya Parua March 25-29, 2002Calor 2002 Finer Debugging           ….…. …          ….…. …                  x8 x1  L1 SCA up L2 SCA ADC down Mean value ADC counts L1 SCA up L1 SCA down L2 SCA  Most problems are traced to slower SCA chips.  More than 250 SCA chips (~1%) have been replaced

Nirmalya Parua March 25-29, 2002 Coherent Noise Studies. Normalized Covariance = (1/n)  { ( Xi – Xave ) ( Yi – Yave ) / (  x  y ) } Look at the coherence with other channels. Check the noise introduced by the other detectors.

Nirmalya Parua March 25-29, 2002 L1 Calorimeter Trigger Miscabling All towers at |  | <0.8 are instrumented, complete coverage coming soon

Nirmalya Parua March 25-29, 2002 Summary of Installation & Commissioning  Only missing piece is Trigger readout for |  |>0.8

Nirmalya Parua March 25-29, ns 98.01% -20 ns 99.69% -10 ns 99.92% 10 ns 99.93% 20 ns 99.71% 50 ns 98.23% Sampling time vs amount sampled Nominal sampling time varies from ±10ns  Pedestal Values were different for Early, Nominal or Late sampling.  Corrected after putting additional CAPS on BLS boards. Timing Studies 132 ns early 132 ns later Nominal

Nirmalya Parua March 25-29, 2002 Online Data Quality Check  Shifter’s are continuously monitoring quality of data.  When hot cells are found corresponding readout channels are suppressed.

Nirmalya Parua March 25-29, 2002 Calibration Using Pulser Pulser signal injected here (measured in DAC counts) DAC/1000  Non linearity 1000  For Lower DAC values non linearity is significant but can be parametrized (same for all channels). ADC 8181 saturation pulser ADC readout pulser shaper output More in Ursula Bassler’s talk

Nirmalya Parua March 25-29, 2002 Effect of Non Linearity Non Linearity seems to have significant effect but can be corrected off line.

Nirmalya Parua March 25-29, 2002 W/Z candidate With Non-linearity correction put in W  e (no jets) selection Events/2 GeV/c 2 M T (GeV/c 2 ) Events/2 GeV/c 2 M T (GeV/c 2 ) W(  e  +jets selection 118 events Signal:~ events Signal:~200 Mean 83.7 Mean 89.4

Nirmalya Parua March 25-29, 2002Calor 2002 Multi jet events 2-jets event E T jet1 ~230GeV E T jet2 ~190GeV 3-jets event E T jet1 ~310GeV E T jet2 ~240GeV E T jet3 ~110GeV E T ~8GeV A. Kupco

Nirmalya Parua March 25-29, 2002 QCD Physics Only statistical errors

Nirmalya Parua March 25-29, 2002 Jet Energy Scale Et=27 GeV Et=24 GeV Photon-jet Events

Nirmalya Parua March 25-29, 2002 Outlook  D0 has undergone major detector upgrade.  Liquid Argon Calorimeter remained untouched.  But major upgrade for readout has been done.  We are making rapid progress in understanding new calibration, energy scale etc.  Benchmark Physics processes are being scrutinized to better understand the detector.  New results will become available soon.