The Calorimeter Upgrade

1. gap used to form trigger and sample baselines 3.56 ms Run I 6x6 superbunch gap 4.36 ms 2.64 ms 396ns Run II 36x36 2” write address decoder/control reset input ..x48.. out ref cap ref read address decoder/control VME • Pulser : • Controler • DC Generator Trigger 6 commands (3x2) 96 curents 1 motherboard (48 channels) ADC-ADCfit ADCmax Preamp. box 2 Fanout (2x3x16 switchs) switch The Calorimeter Upgrade • Run I  Run II • increase of the Beam Energy • E (TeV): 1.8 2.0 • increase of the Luminosity : • L (cm-2 sec-1): 2x1031 2x1032 • modification of bunch structure: • decrease of interaction time • Dt : 3.6 ms 396 (132) ns this gap is too small to form trigger and sample baseline Run II : No modification of the calorimeter structure New Electronics due to timing constraints • DØ Calorimeter: • Uranium / liquid Argon • 55000 channels • |  |<4 • D  D = 0.1  0.1 • (em) = 15% / E • (had) = 50% / E • Excellent Run I performances : • low noise: 10 MeV • linearity < 0.5 % SCA analog delay > 4 ms, alternate new low noise preamp & driver • Signal shaping with peak • sampling time at 400 ns • Analog buffering for 4ms • before L1 trigger decision Trig. sum Bank 0 Electronic Calibration SCA (48 deep) SCA (48 deep) x 1 Filter/ Shaper Output Buffer Preamp/ Driver SCA BLS x 8 SCA (48 deep)  Replacement of Preamps, Shapers, BLS  addition of SCA  new calibration. SCA (48 deep) Bank 1 Additional buffering for L2 & L3 Replace cables for impedance match Shorter shaping 400ns Switched Capacitor Array Preamplifiers • Not designed for simultaneous • read and write operations • Calorimeter preamp: • hybrid on ceramic • 48 preamps on • one motherboard • similar to previous version except • Dual FET frontend • Compensation for detector capacitance • Faster recovery time  two SCA banks alternate reading and writing • approximately deadtimeless • to L1 rate up to 100kHz • Only 12 bit dynamic range preamp driver New output driver for terminated signal transmission FET  low and high gain path for each readout channel (X8/X1)  maintain 15 bit dynamic range Electronic Calibration System • Expected Run II Noise contributions: • (compared to Run I) • Electronics noise:  1.6 • increases due to shorter shaping times (2 ms to 400 ns: as t) • decrease due to lower noise preamp (2 FET input: as 1/  2) • Uranium noise:  2.3 • decrease due to shorter shaping times (as  t) • Pile-up noise:  1.3 • increase due to luminosity (as  L) • decrease due to shorter shaping times (as  t) • fast pulse similar to physics signal • optimized calibration for various • detector capacitances possible • precision better than 1% Pulser linearity Frédéric.Machefert@in2p3.fr Pulse height Run II calorimeter electronics performances equivalent to Run I for a 10 times higher luminosity .