1. HMPiD upgrade variant; simulation status N. Smirnov Physics Department, Yale University, May, 06. CERN visit

2. GEANT Simulation Y Z X 50 cm AeroGel, 10cm UV Mirror, spherical shape in ZY Double sided Read-out plane Triple GEM foils with CsI CaF2 Window C4F10 gas CF4 gas Particle track & UV photons R position: ~450 cm. Bz: 0.5 T Detector response: GEANT hits (π+, Pt~10. GeV/c; local coordinate system, cm) UV photoelectrons from “CF4 + Mirror” side UV photoelectrons from “C4F10 + Window” side MIP

3. ~ 2m ALICE Club - May 2, 2005 Paolo Martinengo

4. GEANT Simulation, ALICE set-up R Z Double sided Read-out plane Triple GEM foils with CsI CaF2 Window UV Mirror, spherical shape in ZY AeroGel, 10cm C4F10 gas CF4 gas VBHC GEM D. Realistic material budget and position for: Si Vertex, TPC*, TRD, ToF + 100 modules of HMPiD (100 x 100 x 100 cm 3 )

5. Occupancy; N of Hits / Detector / Event MIP hits Central HJ PbPb event “Standard” Central PbPb event UV hits C4F10 CF4 Sum Occupancy ( 5 x 5 mm 2 pad ) – (1.5 – 2. )% Detector Number

6. Who is “responsible” for … Particle Id, GEANT R Vertex, cm Particle Id, GEANT R Vertex, cm e+/- μ+/- π+/-

7. One detector (#61) response X - MIP position - Track “reflection” from mirror; “circle center” - Photo-electrons from “bottom” gas UV light + window. Red circle – track has hits in TPC - Photo-electrons from “top” gas UV light + mirror green means Sc. Light from CF4

8. One Detector response Particle, GEANT Identification P, GeV/c R vertex, cm e+/- μ+/- π+/-

9. GEANT Simulation, ALICE set-up R Z Double sided Read-out plane Triple GEM foils with CsI CaF2 Window UV Mirror, spherical shape in ZY AeroGel, 10cm C4F10 gas CF4 gas VBHC GEM D. 30 x 30 cm2 COMPAS read-out strip structure GEM D. Realistic material budget and position for: Si Vertex, TPC*, TRD, ToF + 100 modules of HMPiD (100 x 100 x 100 cm 3 ) *For TPC all “read-out” stuff is as realistic as possible to simulate dE/dX performance

10. High Pt trigger using “fast” tracking data (?!) “R2D” Does not need primary Vertex position “ALICE” Needs primary Vertex with ~n cm resolution SLFtoBLine R fit, DCA to Vertex in XY ToF hit Sigma (cm): 0.02 0.2 0.02 0.9 ~1 m ~4 m Straight Line Fit in RZ “Z” DCA to Vertex cut Y X Y X SLDtoV

11. Track finding and selection for HMPiD only (plus Primary Vertex) SLDtoV, cm Pt, GeV/c With cuts selected: (~ > 6. GeV/c ) I. 32 π+ /event; Pt = (8. – 10.) GeV/c  80% efficiency II. 32 π+ & Central PbPb HJ event ( ~ 2200 particles / rapidity)  70% efficiency (the SAME tracks that were found in step I ) III. Only “Standard Central ALICE” event ( ~ 8000 particles / rapidity )  1 track was found, Pt = 5.6 GeV/c This “high Pt trigger approach” can be checked / tested with “available” equipments and in reasonable short period of time

12. ALICE TPC: 159 pad-rows; 63x (0.75x0.4) + 64x(1.x0.6) + 32x(1.5x0.6) Ne+CO2 (10%), B=0.5 T, Dl = Dt = 220 μm/cm -1 Drift <= 250 cm. Vdr = 2.84 cm/μs (88 μs max) Cluster efficiency – 85%, Truncated – 60% dE/dX P, Gev/c π, K, p “Perfect” in simulation: gas amplification calibration, P – reconstruction, one particle / event, |η| < 0.9; No “tail subtraction” problem; FADC approach. Simulation approach: N inter./cm; N el. / cluster; For each e- : (Ekin, range, Drift, wire position, timing, gas amplification, charge on pads); FEE shaping and noise; Hit position and Q reconstruction.

13. Points to be discussed  Beam test 2 new frames foil support structure test/checking set-up HV connectors / dividers 15 foils (10x10 cm2)  3 GEM tracking detectors set-up like COMPAS size and read-out (?) FEE, Cables, HV, DAQ, Gas supply, …  Gas studies CF4 and mixtures(?) scintillations and N0(?) CF4 + CH4 as an example (?) Instead of Conclusion