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NIU Workshop R. Frey1 Reconstruction Issues for Silicon/Tungsten ECal R. Frey U. Oregon NIU Workshop, Nov 8, 2002

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NIU Workshop R. Frey2 Outline ECal Physics Goals Current implementations SD TESLA The hardware constraints Resolution requirements What simulation studies do the detector prototypers (we) want the simulators (us) to do -- discussion

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NIU Workshop R. Frey3 ECal Goals Photons in Jets Id. with high efficiency and measure with reasonable E resolution … in a very busy environment. Demand eff>95% with high purity Photon shower imaging vertexing (impact param. resolution 1 cm) º→ Separation from nearby photons, MIPs, h-shower fragments MIP tracking (h , muons) Id. Hadrons which shower in ECal Reconstruction of taus (eg → → º → - -mip) b/c reconstruction – include neutrals in M Q estimate e’s and Bhabhas (Lum. spectrum) – easy (readout dynamic range) Backgrounds immunity Segmentation Timing

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4 SD Si/W 5x5 mm 2 pixel 50M pixels For each (6 inch) wafer: 1000 pixels (approx) One readout chip (ROC) Simple, scalable detector design: Minimum of fab. steps Use largest available wafers Detector cost below $2/cm 2 Electronics cost even less A reasonable (cheap?) cost M. Breidenbach, D. Freytag, G. Haller, M. Huffer, J.J Russell Stanford Linear Accelerator Center R. Frey, D. Strom U. Oregon V. Radeka Brookhaven National Lab

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5 Readout chip connections Use bump-bonding technique to mate ROC to array of pads on wafer

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6 Pad Silicon wafer PCB Aluminium Cooling tube VFE chip 1.3 mm 1.0 mm 0.5 mm Thermal contact Gluing for electrical contact AC coupling elements ? power line command line signal out CALICE design with electronics inside detector

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NIU Workshop R. Frey7 Si Timing Dynamic range: MIPs to Bhabhas About factor 2000 range per pixel Want to maintain resolution at both ends of scale Timing: What do we need? NLC: 200 ns bunch trains – Do we need to resolve cal. hits within a bunch? Bhabhas: 15 Hz for >60 mrad at 10 34 What about 2-photon/non-HEP background overlays? Exotic new physics signatures Can try to provide timing for each pixel Is ≈10 ns resolution sufficient ?

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NIU Workshop R. Frey8 What are the constraints from the hardware? Dynamic range OK Transverse segmentation almost independent of cost within reasonable range (watch thermal load) Segmentation < Moliere radius is OK Radiation damage probably non-issue Timing perhaps possible with resolution of 10-20 ns Moliere radius ( 9mm x 2) Energy resolution ↔ long. sampling ↔ Money More coarse with ECal depth Also: pattern recognition implications

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NIU Workshop R. Frey9 e+e-→jj, 200 GeV; LCDRoot FastMC Perfect pattern recog. 0.01/sqrt(E) 0.01 (EM) 0.01/sqrt(E) 0.01 (HAD) ← 0.10/sqrt(Ej) ← 0.11/sqrt(Mjj)

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NIU Workshop R. Frey10 EM: 0.12/sqrt(E) 0.01 HAD: 0.50/sqrt(E) 0.02 0.18/sqrt(Ej) 0.19/sqrt(Ej) EM: 0.20/sqrt(E) 0.01 HAD: 0.70/sqrt(E) 0.02 0.20/sqrt(Ej)

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11 E > 0.5 GeV 0.19/sqrt(Ej) EE E h0 E > 1 GeV, E h0 >1 GeV 0.20/sqrt(Ej) E > 2 GeV 0.20/sqrt(Ej)

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NIU Workshop R. Frey12 What simulations studies do we need? EFA tuning ↔ segmentation -MIP separation , tau, pi-zero reconstruction Background overlays ↔ timing requirement Longitudinal sampling EGS4 Geant4 Distribution of hit occupancy in a detector wafer

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