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Calorimeter Parameters and Choices

Calorimeter Parameters and Choices. Peter Nemethy MECO Collaboration Meeting Irvine - February 6-7, 2005. Present Configuration (new) REF DESIGN. 135cm LONG (down fr.150cm) LEAD TUNGSTATE At Temp = –24deg C 4 VANES of 8 x 36 = 288 crystals Total: 1152 CRYSTALS PWO crystal size:

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Calorimeter Parameters and Choices

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  1. Calorimeter Parameters and Choices Peter Nemethy MECO Collaboration Meeting Irvine - February 6-7, 2005

  2. Present Configuration (new) REF DESIGN 135cm LONG (down fr.150cm) LEAD TUNGSTATE At Temp = –24deg C 4 VANES of 8 x 36 = 288 crystals Total: 1152 CRYSTALS PWO crystal size: 3.75 x 3.75 x 12 cm3 13.5 RL 2 APD/Crystal 13 x 13 mm2 Preamps at Detector Shaper Amps outside. Peter Nemethy Calorimeter Parameters and Choices

  3. Peter Nemethy Calorimeter Parameters and Choices

  4. PARAMETERS and CHOICES • LENGTH in Z (Scales ALL $ , exc. Mech. and cooling)? => ACCEPTANCE, EDGE EFFECTS. • CALORIMETER DEPTH (Scales XTAL Volume $)? => ACCEPTANCE, RESOL, EDGE EFFECTS, PUNCHTHRU • HV POWER SUPPLY GANGING (scales HV $)? • CRYSTAL Transverse Dimension(?): used • APD choice ? • 2 APD / Crystal to 1 (?) N. Peter Nemethy Calorimeter Parameters and Choices

  5. ACCEPANCE vs CAL LENGTH For 2 different Crystal depths: Peter Nemethy Calorimeter Parameters and Choices

  6. Peter Nemethy Calorimeter Parameters and Choices

  7. COST (w. CONT) vs ACCEPTANCE • [Previous: 150cm -> 135cm: Lose 2% Acceptance] • 12 cm deep, 135cm -> 120cm: • LOSE 3% ACCEPTANCE……save $ 572K • 12 cm deep, 135cm -> 112.5cm: • LOSE 8% ACCEPTANCE……save $ 858K • 12 cm deep, 135cm -> 105cm: • LOSE 13% ACCEPTANCE…save $ 1144K • 10 cm deep, 135cm -> 120cm: • LOSE 7% ACCEPANCE……save $ 799K Peter Nemethy Calorimeter Parameters and Choices

  8. Calorimeter Depth 12cm to 10cm • Save ~ $225K. Edge, Punchthru and APD Nuclear Counter worse. • Ratio of FWHH(10cm)/FWHH(12cm) = 5.6MeV / 3.1MeV = 1.8 • Punchthru and Nuclear Counter Effect needs detailed sim. Peter Nemethy Calorimeter Parameters and Choices

  9. (more) CHOICES • GANGING HV: 2 APD’s per CHANNEL. save $ 240K • Hardship and convenience: gain balancing harder; Level-0 trigger? 5V => 20% Gain Change (at 1700V) • CRYSTAL TRANSVERSE SIZE CHANGE Scaled already (3.75cm -> 3.0cm) Channels scaled by 1.5 Matches manufacturing capability and Moliere radius 2cm Light Collection Loss under study. Peter Nemethy Calorimeter Parameters and Choices

  10. (no more) CHOICES • APD CHOICE and smaller AREA: DEGRADE S/N and resolution. Complicated, studies and info needed, if… $ vs area scaling? 3 sources. need budgetary quotes. Physics =>resolution [now est. 7.9% (5.6%)] trigger rate? Elec noise scales with light coll, photostatistics w. sqrt of. Light Collection scales w. area (or somewhat better), Measuring at NYU now. Detector Capacitance varies widely, not area scaling: [ex. Hamamatsu 1x1cm 300puff -- RMD 1.3x1.3cm 150puff]. • 2 APD/ XTAL to 1 ? DON’T! Of course big save $ 900K. But lose control of APD nuclear counter effect (NCE). No trustable reconstructed energy (infinite tail) Increased trigger rate, NCE probab/event low but base is all >50MeV DIO showers, much higher rate. [Needs detailed MC study] Peter Nemethy Calorimeter Parameters and Choices

  11. CONCLUSIONS for DISCUSSION • SHORTER CALORIMETER: yes. $ and physics scaling understood. 120cm for sure, 112.5cm maybe, 105cm hurts. • Depth Change 12cm to 10cm, not as favorable as shorter cal. • HV ganging: doable though not convenient. • APD choices – prefer not to degrade. No offer on BLing timescale. • 1 APD/CRYSTAL: don’t. Peter Nemethy Calorimeter Parameters and Choices

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