1. Comparison of Endcap CID-PID Klaus Föhl PID meeting 27/3/2007 panda-meeting Genova Focussing Lightguides Time-of-Propagation Proximity Focussing

2. Focussing Lightguides focal plane coord. [mm] lightguide number

3. Focussing Lightguides short focal plane 50mm ~1mm pixels needed optical errors exist thicker plate a problem 125mm disc-PMT focal plane 100mm pixel width 2-3mm benign optics thicker plate ok 200mm disc-PMT

4. Focussing Lightguides no LiF plate

5. Focussing Lightguides no LiF plate LiF plate performance decrease due to poor phi resolution for particle track near the edge, partial remedy to be investigated N.B. only rough matching of current geometry homework: for photon area of large angle tracks increase phi resolution by subdividing pixel length all calculations: =300nm-600nm Quantum Efficiency 20% n 0 =15.28/mm optimisation within the sum rule 6K pixels

6. Time-of-Propagation already investigated –excess radius –pixelisation effect  fall-off at larger angle to investigate –rectangular hole –different hole coatings  proper ray-tracing –several outer shapes –path ambiguties (with similar travel time) r=900mm and 1100mm r=900mm (23deg equivalent) 30ps 512 pixels 256 pixel 128 pixel not relevant not relevant

7. Time-of-Propagation hexagon with rectangular hole ToP disc Gießen Design Saclay version: hexagonal shape rectangular black hole reflective holeabsorbing hole 8 deg photon number corresponding to 54 tracks

8. Time-of-Propagation TOP  =70ps N 0 =344 n 0 =17.19/mm [ref: Markus Ehrenfried, Saclay talk] hexagon with rectangular hole circle black rectangle circle mirror rectangle hexagon mirror rectangle hexagon black rectangle circular with rectangular hole comparison: hexagon 960mm width or round disc 1100mm radius  t =30ps

9. Time-of-Propagation single photo timing crucial performance increase comes with more tracks in the time-angle-plane reflective holeabsorbing hole 16 deg these calculations: =400nm-800nm Quantum Efficiency 30% n 0 =17.19/mm per band:  n(group)=0.0213 (inspired by [480nm-600nm]   n=0.00615

10. Proximity Focussing design variation with mirror and the expansion volume upstream radiator placed closer to EMC

11. Proximity Focussing C6F14+ CsI+GEM radiator 15mm expansion 135mm [no] mirror

12. Proximity Focussing detection plane needs to be larger than the radiator size to catch all photons on the possible cones or mirrors at the fringes to fold Cherenkov cone back onto the active area design variation with mirror and the expansion volume upstream radiator placed closer to EMC

13. Performance comparison focussing lightguide ToP C6F14+ CsI+GEM radiator 15mm expansion 135mm [no] mirror

14. Performance comparison radiator X0 [ ]@QE n 0 [1/mm] N 0 N 0 *sin ^2 *geometry pixels photon rate..per area..per pixel Focussing 15mm SiO 2 12% 300nm-600nm@20% 15.28 225/cos 121 66 6K 4E9 1/s 1.25E6 1/s/cm^2 0.66E6 1/s/pixel ToP 20mm SiO 2 16% 400nm-800nm@30% 17.19 344/cos 185 100 (75) 1K (?) 6E9 1/s 4.5E6 1/s/cm^2 (100%) 6E6 (?) 1/s/pixel Proximity 15mm C 6 F 10 7% ( +window ) 40 24-40 3E4 – 1.2E5 2.4E8 1/s ~1E4 1/s/cm^2 Cherenkov photons N=d*n 0 *sin C ^2=N 0 *sin C ^2 lightguide PMT 128* 25cm2 2E7 interactions/s ; multiplicity 6 ; Endcap region ~50% in CM  6E7 particles/s

16. Time-of-Propagation

17. Proximity Focussing

20. Photon yield – visible photons photons produced in radiator plus CsI quantum efficiency absorption plus quantum efficiency 20mm 10mm curves show photon yield for an energy interval starting at E_photon=5.4eV r.home.cern.ch/r/richrd26/www/hmpid/richsim.html material properties from RICHSIM web page at CERN

21. Simulation ingredients proper Cherenkov photons number and colour refractive index dispersion –Cherenkov angles –Snell's law absorption length quantum efficiency statistical analysis normal incidence particles only  maths simplification no angular straggling liquid without vessel no detector pixels (assumed to be small) Fresnel formula simplified (Brewster angle being close) perfect mirror Simplifications & Approximations C6F14 CsI mirror

22. Hit pattern response shape (1000 particles) photons 1 particle  =0.99 The particle distance is the average of the photon radial distances resulting from one charged particle. Particle distance mean and sigma are computed for samples of 1000 events  =1 and 1000 events  =0.99 and sigma separation & 4  -limit derived.

23. Performance comparison focussing lightguide ToP C6F14+ CsI+GEM radiator 15mm expansion 135mm [no] mirror

24. potential edge effects detection plane needs to be larger than the radiator size to catch all photons on the possible cones or mirrors at the fringes to fold Cherenkov cone back onto the active area design variation with mirror and the expansion volume upstream radiator placed closer to EMC

25. performance – radiator width

26. angle dependence preliminary and approximate calculation

27. source of material properties material data used is shown left and below from a RICHSIM web page at CERN r.home.cern.ch/r/richrd26/www/hmpid/richsim.html

28. material transmission radiator thickness

29. Comparison of Endcap PID

31. Time-of-Propagation TOP  =30ps N 0 =344 n 0 =7.64/mm