1. 7/6/2011ECAL Studies1/7 ECAL Studies Jacopo Nardulli

2. 7/6/2011ECAL Studies2/7 Why the ECAL is as it is ? The LOI ILD Ecal structuring comes from an old optimization from H. Videau available here ECAL Optimization from H. Videau He considers a few scenarios with different nr of layers and different absorber thickness Similar studies have now also been done by a LLR PhD student M.S.Amjad and have been presented at the CALICE Meeting in CasablancaCALICE Meeting in Casablanca

3. 7/6/2011ECAL Studies3/7 Two possible studies Keep same radiation length: ECAL with less layers Less expensive, energy resolution can be worse, as the pattern recognition Varying nr of layers and absorber thickness, not the Si thickness Change the radiation length: ECAL with less layers Less expensive, overall performance changes If I change the X0, can have more leakage into the HCAL which could be fixed with a combined ECAL/HCAL analysis Varying nr of layers, absorber thickness and studying performance as a function of the X0 similar to what Angela has done for HCAL.

4. 7/6/2011ECAL Studies4/7 Now only first study: Different ECAL models Altering the number of layers and their absorber thickness in such a way that Total Absorber thickness in the detector remains the same. The analyses included in this talk were done with Single Photon with θ and φ varying in the full range and Energies of 1, 10, 100 and 500 GeV Default model 20 layers in 1 st stack and 9 layers in 2 nd stack

5. 7/6/2011ECAL Studies5/7 Disclaimers Here showing the Energy Resolution vs. the Energy but to get the energy resolution I am not using the official MarlinProcessor which does that –rms90 and mean90- but single Gaussian fits. So do not look at absolute numbers, but at the general trend of the plots THIS IS WORK IN PROGRESS: Not all plots are fully understood

6. 7/6/2011ECAL Studies6/7 Results: changing nr layers in 1 st stack E nergy resolution degrades for low energy We fail to get all the energy and the mean is much lower than the input Energy  Need to use different calibration constants Mean Rec. Energy vs Input Energy Energy Res. vs Input Energy 5.5 55 278

7. 7/6/2011ECAL Studies7/7 Results: changing nr layers in 2 nd stack Mean Rec. Energy vs Input Energy Energy Res. vs Input Energy E nergy resolution degrades, while we have lower degradation in the rec. of all the energy in the event Changing 2 nd stack affects high energy photons which deposit more energy 9.5 89 420

8. 7/6/2011ECAL Studies8/7 Results: changing nr layers in 1 st and 2 nd stack Mean Rec. Energy vs Input Energy Energy Res. vs Input Energy 8.6 81 360

9. 7/6/2011ECAL Studies9/7 Spares All same plots in barrel and forward region

10. 7/6/2011ECAL Studies10/7 Barrel Results: changing nr layers in 1 st stack

11. 7/6/2011ECAL Studies11/7 Barrel Results: changing nr layers in 2 nd stack

12. 7/6/2011ECAL Studies12/7 Barrel Results: nr layers in 1 st and 2 nd stack

13. 7/6/2011ECAL Studies13/7 Forward Results: changing nr layers in 1 st stack

14. 7/6/2011ECAL Studies14/7 Forward Results: changing nr layers in 2 nd stack

15. 7/6/2011ECAL Studies15/7 Forward Results: nr layers in 1 st and 2 nd stack