Calorimeter Upgrade The Tevatron and Dzero Upgrades Gregorio Bernardi on behalf of the Dzero Collaboration The Tevatron and Dzero Upgrades From Run I to Run II, in brief Preshower Detectors CPS: design, status... FPS : ...expected performances Calorimeter Electronics Constraints at Run II System Description Intercryostat Detector Objectives and status

Timings Bunch structure Run I 6x6 Run II 36x36 gap used to form trigger and sample baselines 3.56us Run I 6x6 superbunch gap 4.36us 2.64us 396ns Run II 36x36 this gap is too small to form trigger and sample baseline We expect the bunch structure to evolve to a minimum 132 ns between bunches - design to that We expect 3 gaps, gap size must be a multiple of 132ns (7 RF buckets)

Experiment Physics program at Run II (driven by high pT physics) Searches for phenomena beyond the SM Top quark studies Electroweak measurements QCD tests B physics Accelerator environment implies: Fast electronics, pipeline Sophisticated trigger systems Radiation hard detector components

E.M. Calibration Use J/Psi , Upsilon , Z

DÆ Upgrade Forward Scintillator + New Electronics, Trig, DAQ New Solenoid, Tracking System SMT, SciFi,Preshowers Shielding Forward Mini-drift chambers Forward Scintillator Central Scintillator + New Electronics, Trig, DAQ

Tracking System Fiber Tracker Silicon Microstrip Tracker Forward Preshower Solenoid Central Preshower

Central Preshower Central Preshower already mounted on the solenoid Scintillator + Lead Performances studied with MC and cosmic rays

Central Preshower Simulation results: Good spatial resolution Preshower recovers resolution.

Forward Preshower Azimuthal wedges (u,v) scintillator/lead with readout via fibers side view

Fwd Preshower Azimuthal Wedges ready Test beam results

Fwd Preshower Test Beam Results (FNAL ‘97)

Calorimeter Electronics Objectives: Accommodate reduced minimum bunch spacing from 3.5 us to 396 or 132 ns Storage of analog signal for 4us for L1 trigger formation Generate trigger signals for calorimeter L1 trigger Maintain present level of noise performance and pile-up performance Means Replace preamplifiers Replace shapers Add analog storage Replace Calibration System

Calorimeter Electronics SCA analog delay >4usec, alternate new low noise preamp & driver Trig. sum Bank 0 SCA (48 deep) SCA (48 deep) Preamp/ Driver Filter/ Shaper x1 Output Buffer BLS SCA Detc. x8 SCA (48 deep) SCA (48 deep) Bank 1 Additional buffering for L2 & L3 Replace cables for impedance match Shorter shaping 400ns 55K readout channels Replacement of Preamps, Shapers, BLS, addition of SCA, new calibration.

Preamplifier similar to previous version except Dual FET frontend Compensation for detector capacitance Faster recovery time New output driver for terminated signal transmission New calorimeter preamp, hybrid on ceramic. Forty eight preamps on a single motherboard 2” FET driver preamp

SCA Not designed for simultaneous read and write operations cap ref input write address decoder/control read address decoder/control ..x48.. ref reset out Not designed for simultaneous read and write operations two SCA banks alternate reading and writing approximately deadtimeless to L1 rate up to 100kHz Only 12 bit dynamic range low and high gain path for each readout channel (X8/X1) maintain 15 bit dynamic range

Calorimeter Electronics Upgrades Cables from cryostat to preamps replace 110 ohm cables with impedance matched 30 ohm cables to minimize sensitivity to reflection Preamp motherboards 48 preamp hybrids per motherboard -- for improved high frequency performance BLS motherboards/ Crate Controller 48 BLS hybrids/motherboard to accomodate new SCA and shaper New/additional controls:coordinating the 144 analog samples per channel Power Supplies use low noise commercial supplies power requirements increased New Calibration System accommodate timing constraints and have same or better precision.

Noise Contributions Reoptimized three contributions Electronics noise: increases due to shorter shaping times (2 microsnds to 400 ns) (as sqrt(t)) decrease due to lower noise preamp (2 FET input) (as 1/sqrt(2)) Uranium noise: decrease due to shorter shaping times (as sqrt(t) ) Pile-up noise: increase due to luminosity (as sqrt(L)) decrease due to shorter shaping times (as sqrt(t))

Expected Noise Design for Which leads to Pile-up effect on physics ? 400 ns shaping lower noise -- 2 FET input luminosity of 2x1032 Which leads to electronic noise increase of 1.6 uranium noise decrease of 2.3 pile-up noise increases by 1.3 comparable noise performance at 1032 with new electronics as with old electronics at 1031 Pile-up effect on physics ? The W mass “benchmark” has been simulated and confirms that pile-up will not limit our W mass at Run II.

Intercryostat Detector (ICD) Objectives Maintain ICD performance in presence of a magnetic field and additional material from solenoid Improve coverage for the region 1.1<eta<1.4 Design A scintillator based Intercryostat Detector (ICD) with phototube readout similar to Run I design Expected Physics output Provides improvement to jet energies and missing energy in the region between the central and end cryostats

ICD Design Detectors 16 super-tiles per end with total of 384 scintillator tiles covering 1.1<eta<1.4 WLS fiber readout of scintillator tiles. Re-use existing PMT’s Clear fiber light piping to region of low field Calibration scheme as for L.Ar calo. But with adapted pulse

Conclusions Dzero is upgrading its detector L.Argon calorimeter untouched Harder machine conditions and new environment (solenoid) New Calorimeter Electronics Improved ICD New Central and Forward Preshower Similar Performances Detectors close to be ready to start taking data in Summer 2000