1. Simulation / reconstruction with GEMs at BM@N BM@N DAC 22.06.2016 A.Zinchenko, A.Kapishin, V.Vasendina for the BM@N collaboration VBLHEP, JINR, Dubna, Russia

2. 2 Outline 1. GEM tracker acceptance 2.„Microsimulation“ of GEMs 3.Performance of GEM tracker start version 4.STS + GEM tracker

3. 3 GEM tracker acceptance

4. 4

5. 5 GEM detector parameters D. Baranov

6. GEM microsimulation D. Baranov 6

7. GEM angular characteristics D. Baranov 7

8. 8 GEM detector start configuration 6 stations: Z (cm) = 30 – 45 – 60 – 80 – 100 – 130 Stereo angles: 0 – 15 deg in stat. 1-6 Pitch: 800 um in stat. 1-6 1-4 stations beam

9. 9 Momentum resolution Generator: QGSM, d + 12 C, E kin = 4 GeV, minbias Geometry: 6 stations of GEM Magnetic field: FieldMap - field_sp41v1_ascii_Extrap.dat (B = 0.44)

10. 10 Λ reconstruction (d+C) Data set Generator: QGSM, d + 12 C, E kin = 4 GeV, minbias, 0.5M events Geometry 1: 6 thin stations of GEM Geometry 2: 6 thick stations of GEM (3mm) Magnetic field: B = 0.44 No PID 1 2

11. 11 Λ reconstruction (C+C) Data set Generator: UrQMD, 12 C + 12 C, E kin = 4 GeV, b = 0 - 3 fm, 0.1M events Geometry: 6 thin stations of GEM Magnetic field: B = 0.44 No PID

12. 12 BM@N geometry CBM STS stations: 1+1+2+2 BM@N: STS + GEM STS: 48x40, 48x40, 72x40, 72x40 cm

13. 13 STS geometry 6.2 cm × 2.2 cm6.2 cm × 4.2 cm6.2 cm × 6.2 cm few sizes, small numbers fill gaps at beam hole standard sensors throughout the stations Silicon microstrip sensors: 1024 strips per sensor 15° stereo angle 60 µm strip pitch  Stations have a modular structure and are constructed from 300 µm thick double-sided silicon microstrip sensors.  Groups of sensors (sectors) are individually read out with electronics located at the perimeter of the stations.  Signals from the sectors are sent through thin aluminum-polyimide micro-cables to the front-end electronics.

14. 14 Track reconstruction

15. 15 Λ reconstruction (Au+Au) GEM (12 stations) STS (4 stations) + GEM (8 stations) Data set Generator: UrQMD, Au+Au, E kin = 4.5 GeV, b = 0 - 3 fm, 10 kevents Geometry 1: STS (4 stations) + GEM (8 thick stations) Z (cm) : 30, 40, 50, 60, 90, 120, 150, 180, 220, 260, 305, 350 Geometry 2: GEM (12 thick stations) Z (cm) : 30, 45, 60, 80, 100, 130, 160, 190, 230, 270, 315, 360 Magnetic field: B = 0.44 No PID Size: 4 GEM- 60x60, 60x60, 80x80, 80x80 cm 4 STS - 48x40, 48x40, 72x40, 72x40 cm

16. 16 Summary 1.Simulation details do not seem to affect detector performance too much 2.Several silicon first stations (STS) could improve the performance