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The CLEO-c event environment Subsystem Plans Tracking Calorimetry Particle ID Muon Detector

CLEO-c Detector Issues. The CLEO-c event environment Subsystem Plans Tracking Calorimetry Particle ID Muon Detector Trigger DAQ Conclusions. Mats Selen University of Illinois. The CLEO-III Detector. Event Environment. Details depend on energy, although generally speaking:

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The CLEO-c event environment Subsystem Plans Tracking Calorimetry Particle ID Muon Detector

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  1. CLEO-c Detector Issues • The CLEO-c event environment • Subsystem Plans • Tracking • Calorimetry • Particle ID • Muon Detector • Trigger • DAQ • Conclusions Mats SelenUniversity of Illinois CLEO PAC 28/September/01 M. Selen, University of Illinois

  2. The CLEO-III Detector CLEO PAC 28/September/01 M. Selen, University of Illinois

  3. Event Environment • Details depend on energy, although generally speaking: • Multiplicities will be lower (about half). • Tracks & showers will be softer. • Physics cross-sections will be higher. • ~ 500 nb at the ” (includes Bhabhas) • ~ 1000 nb at the J/ (just resonance) • Relative backgrounds rates will be lower. CLEO PAC 28/September/01 M. Selen, University of Illinois

  4. Tracking System • CLEO-III drift chamber (DR3) is very well suited to running at lower energies. • We will probably lower the detector solenoid field from 1.5 T to 1.0 T. • This will shift the PT for a given curvature down by the same factor. • The silicon detector presents two problems. • It represents a lot of material • 1.6% X0 in several scattering layers. • CLEO-c momentum resolution as already multiple-scattering dominated(crossover momentum is ~1.5 GeV/c). • It seems to be dying from radiation damage. • Performance is degrading fast. CLEO PAC 28/September/01 M. Selen, University of Illinois

  5. ZD Upgrade Plan Replace the 4-layers of silicon with an inner drift chamber (dubbed the “ZD”). • Six layers. • 10mm cells • 300 sense wires. • All stereo (10.3o – 15.4o). CLEO PAC 28/September/01 M. Selen, University of Illinois

  6. ZD Upgrade Plan • Low mass is optimally distributed. • 1.2% X0, of which only 0.1% X0 is in the active tracking volume. • With DR3, this will provide better momentum resolution than silicon. CLEO PAC 28/September/01 M. Selen, University of Illinois

  7. ZD Upgrade Plan • Low cost & quick assembly. • Use same (left over) bushings, pins & wire as DR3. • Won’t have to hire stringers (only 300 cells). • Fabrication will be complete by late summer 2002. • Will use existing readout electronics. • Preamps build from existing parts & PCBs. • Eight 48-channel data-boards from slightly modified existing spares. • TDC’s from spare pool and from muon system. • Ten cell prototype has proven that design in sound (both mechanically and electrically). CLEO PAC 28/September/01 M. Selen, University of Illinois

  8. Calorimeter • Very well suited for CLEO-c operation. • Barrel calorimeter functioning as well as ever. • New DR3 endplates have improved the calorimeter end-cap significantly (now basically as good as the barrel). • The “good” coverage now extends to ~93% of 4p. • Large acceptance key for partial wave analyses and radiative decays studies. • No changes needed. CLEO PAC 28/September/01 M. Selen, University of Illinois

  9. Particle-ID • RICH works beautifully! • Complemented by excellent dE/dx. • Will provide virtually perfect K-p separation over entire CLEO-c momentum range. • No changes needed. RICH dE/dx p p K CLEO PAC 28/September/01 M. Selen, University of Illinois

  10. Muon Detector • Works as in CLEO-III. • No changes needed. CLEO PAC 28/September/01 M. Selen, University of Illinois

  11. Trigger • Tracking Trigger • For B = 1.5 T, the combined axial and stereo trigger hardware is ~100% efficient for tracks having PT > 200 MeV/c. • When B = 1.0 T, we expect to have ~100% efficiency for tracks having PT > 133 MeV/c. not real 200 MeV 200 MeV Tracking Trigger Efficiency versus 1/P(GeV) for hadrons Tracking Trigger Efficiency versus 1/P(GeV) for electrons CLEO PAC 28/September/01 M. Selen, University of Illinois

  12. Contained shower Simulated Efficiency Threshold = 500 MeV CLEO-II mode Shared mode Trigger… • Calorimeter Trigger • During CLEO-III running the mode of combining analog signals was the same as that used in CLEO-II. • The trigger was designed to operate in a more efficient “shared” mode, but this was not implemented due to relative timing uncertainties between shared signals. • This problem was addressed during the shutdown, and “shared mode” running will hopefully be implemented soon after turning back on. CLEO PAC 28/September/01 M. Selen, University of Illinois

  13. TILE Board Fixes to improve “Sharing Mode”: Added a coupleof capacitors to back of each board CLEO PAC 28/September/01 M. Selen, University of Illinois

  14. Trigger… • Global Level-1 • Flexible enough to design almost any needed trigger lines. • Rate is not an issue (trigger processing is effectively dead-time-less). • Spares & Maintenance • The spare situation is not ideal • Only a few spares of each kind • In particular, our 6 TPRO boards seem to be quite fragile and we only have 2 spares. • The Hard metric connectors on most of our boards require a very “trained” hand to swap a board without bending pins. • Hard metric connector technology has improved since we designed the trigger, and we are considering the task of rebuilding several back-planes and retrofitting many of the boards to avoid a serious problem as trigger experts leave. CLEO PAC 28/September/01 M. Selen, University of Illinois

  15. Data Acquisition System • Achieved Performance • Readout Rate 150 Hz (prior test) 300 Hz (expected now) 500 Hz (random trigger) • Average Event Size 25 kBytes • Data Transfer Rate 6 Mbytes/sec • Low dead-time: Trigger Rate ~ 100 Hz CLEO PAC 28/September/01 M. Selen, University of Illinois

  16. Data Acquisition System… • The biggest challenge will be running on the J/ resonance where the effective cross-section is ~ 1mb. • Physics Rate ~ 100-200 Hz if L = 1-2x1032 cm-2s-1 and DEbeam = 1 MeV. • We can handle 300 Hz. • With ZD replacing Silicon, the event size could be reduced significantly. • Under almost any assumption, average throughput to tape will be < 6 Mbyte/s, which is compatible with current online system. • Although not anticipated, if necessary there are several straight-forward incremental upgrade paths. • Gigabit switch (already bought). • Faster online computer. • One potential vulnerability is the shortage of spare readout components (TDC’s, for example). • Hope to augment this prior to running. CLEO PAC 28/September/01 M. Selen, University of Illinois

  17. Conclusions • The CLEO-III detector is a beautiful instrument for running at energies around 10 GeV. • It’s performance speaks for itself. • CLEO-c is a small perturbation of CLEO-III. • Apart from machining the end-plates, the whole ZD upgrade will be done in house using existing parts. • All other detector components are OK “as is”. • We are convinced that CLEO-c will be a beautiful instrument for studying charm and resonance physics in the 3-5 GeV regime. • Excellent tracking covers 93% of 4p. • Excellent calorimeter covers 93% of 4p. • RICH provides superb particle ID for 80% of 4p. • Fully capable trigger & DAQ. • Best device to ever accumulate data in this energy range. CLEO PAC 28/September/01 M. Selen, University of Illinois

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