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

2. 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

3. 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

4. 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

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

6. 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

7. 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 ?

8. 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

9. 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)

10. 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)

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

12. 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