1. W Prototype Simulations Linear Collider Physics & Detector Meeting December 15, 2009 Christian Grefe CERN, Bonn University

2. Page 2 December 15, 2009, Christian Grefe Outline Prototype Models & Simulation Calibration & Linearity Resolution Time Structure

3. Page 3 December 15, 2009, Christian Grefe GEANT4 Model Four different prototype geometries CALICE iron prototype (Fe): 16mm Fe + casette (30mm total gap size) W, including steel support plate: 10mm W + 2mm Fe + cassette (30mm total) W, no steel support (W_noFe): 10mm W + cassette (30mm total) W, no steel and minimal air gap (W_noAir): 10mm W + cassette (22mm total) Compact.xml allows for easy and quick modification (more setups can be studied easily)

4. Page 4 December 15, 2009, Christian Grefe Simulation slic v. 2.7.2 (GEANT4 v.9.2.0) All four different geometries Pions and electrons with 1, 5, 10, 15, 20, 25, 30 GeV 1000 events each Total of 56000 events 30 GeV pion

5. Page 5 December 15, 2009, Christian Grefe Hit Combination & Digitization Simulation uses 3x3 cm 2 cells Hits are combined during analysis according to CALICE AHCAL modules Threshold set to 250 keV (~1/4 MIP) Timecut at 250 ns Use (almost) only 66x66 cm 2 W area, because of current module layout 66x66 cm 2 W area

6. Page 6 December 15, 2009, Christian Grefe Cut on MIP-like events More mip-events Introduce cut-off Need to remove MIP-like events in order to improve calibration Use mean and RMS to calculate linearity and resolution

7. Page 7 December 15, 2009, Christian Grefe Linearity (electrons) Very good linearity (as expected) Can clearly separate the Fe, W and W without extra Fe layer cases (different sampling fraction) No impact from short prototype

8. Page 8 December 15, 2009, Christian Grefe Linearity (pions) Bad linearity for low energetic particles Can compensate some of the leakage with different sampling fraction

9. Page 9 December 15, 2009, Christian Grefe Resolution Again well separated results for electrons – lower radiation length leads to better resolution for steel Pions have slightly worse resolution in all W cases – short prototype setup is equally bad for all cases electrons pions

10. Page 10 December 15, 2009, Christian Grefe Impact of Radial Leakage Energy deposition in outer region and inner region are correlated Event selection based on hits in outer region is unlikely to improve linearity and resolution Further studies needed

11. Page 11 December 15, 2009, Christian Grefe Time Structure of Showers For 10 ns resolution the time structure of the shower in Fe and W are very different 50 ns might still be enough to investigate the difference Impact of steel support plate is marginal

12. Page 12 December 15, 2009, Christian Grefe Time Structure of Showers (Short Case) Also the short case would allow to investigate the time structure if the modules would allow for a high time resolution

13. Page 13 December 15, 2009, Christian Grefe Conclusion Simulations performed for four different prototype geometries Even a rather simple analysis shows differences between W and Fe prototypes Big potential for studying hadronic showers in tungsten Already the small setup (20 layers, only use inner 66x66 cm 2 area) can be used to investigate the hadronic shower structure