1. pad design present understanding Tel Aviv University HEP Experimental Group Ronen Ingbir Collaboration High precision design Tel-Aviv Sep.05 1

2. High statistics MC, Fast simulation Design optimization (GEANT) : 1.Granularity and reconstruction algorithm (Log. Weighting).Granularity and reconstruction algorithm (Log. Weighting). 2.Electronics channels (Maximum peak shower design).Electronics channels (Maximum peak shower design). Present understanding design (head on ILC, Crossing angle). Method of counting Bhabha events Summary Collaboration High precision design Tel-Aviv Sep.05 2 Outline

3. Fast Detector Simulation Motivation : High statistics is required to notice precision of : There is an analytic calculation (and approximation) : (Which is the precision goal of the ILC) Luminosity precision determination : N 1 : Reconstructed and generated in acceptance region. N 2 : Generated in acceptance region but reconstructed outside. N 3 : Generated outside acceptance region but reconstructed inside. Collaboration High precision design 3 Tel-Aviv Sep.05

4. High Statistics Simulation BHWIDE generated properties + smearing to simulate detector Changing the bias with a fixed resolution. Collaboration High precision design 4 Tel-Aviv Sep.05

5. High Statistics Simulation Changing the detector resolution with no bias Collaboration High precision design 5 Tel-Aviv Sep.05

6. Data and MC In real life we can include the detector performance (which is measured in test beam) into MC. The only question is: How well should we know the detector performance ? Collaboration High precision design 6 Tel-Aviv Sep.05

7. Logarithmic Weighting Collaboration High precision design 7 Tel-Aviv Sep.05

8. Granularity in theta, GEANT results ResolutionBias Collaboration High precision design 8 Tel-Aviv Sep.05

9. Our basic detector is designed with 30 rings * 24 sectors * 15 cylinders = 10,800 channels Do we use these channels in the most effective way ? Maximum Peak Shower Design 30 rings 15 cylinders 20 cylinders 10 cylinders 24 sectors * 15 rings * (10 cylinders + 20 cylinders) = 10,800 channels 4 rings15 rings11 rings 10 cylinders Collaboration High precision design 9 Tel-Aviv Sep.05

10. Maximum peak shower design Basic Design Angular resolution improvement without changing the number of channels Other properties remain the same Polar Reconstruction 0.11e-3 rad 0.13e-3 rad Collaboration High precision design 10 Tel-Aviv Sep.05

11. Present Understanding (pad option) 15 layers (z) 11 layers (z) 4 layers (z) 10 cylinders (θ) 60 cylinders (θ) Collaboration High precision design Based on optimizing theta measurement 14 Cylinders (mrad) 11 Tel-Aviv Sep.05

12. X- angle background Collaboration High precision design Christian Grah, DESY-Zuethen Beamstrahlung pair background 250 GeV 12 Tel-Aviv Sep.05

13. Method of counting events Collaboration High precision design 13 Tel-Aviv Sep.05 Applying tight acceptance cut on one detector arm. Count events which satisfy the back to back requirement using a band cut. Maximum peak shower design and logarithmic weighting : working with a constant (Beam energy and cells size dependents) + applying differential weighting between the parts. Applying a looser acceptance cut on the second detector arm. Repeat method for the other side of the detector and compare results.

14. Tight cut Out In Eout-Ein Eout+Ein P= 3 cylinders 2 cylinders 1 cylinders Collaboration High precision design 14 Tel-Aviv Sep.05

15. Forward-Backward Balance R L Simulation distribution Distribution after acceptance and energy balance selection Right side PH Left side PH Right PH - Left PH Collaboration High precision design 15 Tel-Aviv Sep.05

16. Performance of present configuration Collaboration High precision design Pad PerformanceParameter 25%Energy resolution 3.5 * 10 -5 (rad) resolution 0.63 (deg) resolution ~ 1.5 * 10 -6 (rad) 25,200 ~19,000 (X-angle) Electronics channels With this performance the goal can be reached. 16 Tel-Aviv Sep.05

17. Next (and immediate) steps Collaboration High precision design 17 Tel-Aviv Sep.05 Taking the present understanding design as a basis design for future simulation. Understanding the criteria for identifying and selecting Bhabha event (maybe better detector resolutions are necessary). Testing the crossing angle recommendation design in a crossing angle Bhabha scattering simulation which includes serpentine magnetic field.