1. 12 th CBM Collaboration Meeting October 13-18, 2008, JINR, Dubna A. Zinchenko 1 (L.Naumann 2, D.Peshekhonov 1, V.Peshekhonov 1 ) 1 VBLHEP, JINR, Dubna 2 Forschungszentrum Dresden-Rossendorf, FZD Feasibility study of the straw tube detector option for some MUCH stations

2. Dubna, 15-October-2008A.Zinchenko2 1.MC 2.Reconstruction 3.Some performance numbers 4.Summary and outlook Outline

3. Dubna, 15-October-2008A.Zinchenko3 Tube diameters: 4, 4, 4, 4 mm; σ drift = 0.2 mm 6 layers per station arranged in 3 doublets: Y, U (+10 o ), V(-10 o ) Geometry

4. Dubna, 15-October-2008A.Zinchenko4 Straw tube occupancy for Au-Au @ 25 GeV

5. Dubna, 15-October-2008A.Zinchenko5 Straw tube occupancy for Au-Au @ 25 GeV

6. Dubna, 15-October-2008A.Zinchenko6 Makes use of L1 Kalman Filter framework (CbmL1SttTrackFinder) Starts from STS tracks Tracking strategy: extrapolate track to STT plane and select hits around track with χ 2 < 20 (100) Track accepted if contains hits from all STT doublets Track reconstruction

7. Dubna, 15-October-2008A.Zinchenko7 Reference tracks: muon tracks from J/ψ found in STS and passing through all layers of STT (producing STT MC points with given MC track ID) Tracking efficiency

8. Dubna, 15-October-2008A.Zinchenko8 J/ψ to dimuon @ 25 GeV w/out background 1165 / 1185 = 98.3 % 1166 / 1194 = 97.7 % 1165 / 1185 = 98.3 % 1166 / 1194 = 97.7 % 100 1106 / 1185 = 93.3 % 1113 / 1194 = 93.2 % 1113 / 1185 = 93.9 % 1118 / 1194 = 93.6 % 20 4 stations (hit merging) 3 stations (hit merging) 4 stations3 stationsχ 2 -cut

9. Dubna, 15-October-2008A.Zinchenko9 J/ψ to dimuon + central Au-Au @ 25 GeV 1157 / 1183 = 97.8 % 1162 / 1195 = 97.2 % 1160 / 1183 = 98.1 % 1162 / 1195 = 97.2 % 100 1063 / 1183 = 89.9 % 1110 / 1195 = 92.9 % 1107 / 1183 = 93.6 % 1120 / 1195 = 93.7 % 20 4 stations (hit merging) 3 stations (hit merging) 4 stations3 stationsχ 2 -cut

10. Dubna, 15-October-2008A.Zinchenko10 STT occupancy inside MUCH is below 10% in stations 4-6 for central Au-Au for 25 GeV/c first track reconstruction results from STS seeds (without MUCH tracking) look promising both for 3 and 4 STT stations Summary

11. Dubna, 15-October-2008A.Zinchenko11 realistic STT geometry STT software performance with MUCH tracks Outlook