Status report on the Asian Solid State Tracking R&D

1. Status report on the Asian Solid State Tracking R&D March 31, 2003 M. Iwasaki University of Tokyo

2. There are two groups working on SI tracker in Asian LC Group • Si m-strip central tracker: • Univ. of Tokyo • Si m-strip intermediate Tracker: • Kyungpook National Univ., • Ewha Univ., Yonsei Univ., • Korea Univ. • Today, I introduce these two groups activities

3. Si m-strip central tracker R&D by Tokyo Group • Univ. of Tokyo Group: M. Iwasaki, H. Aihara • GEANT4 Full simulation study on the SI tracker • 1. Basic detector parameter studies • 2. Photon BG estimation

4. In Linear Collider environment, Central Tracker must be robust  SI tracker is one of the good candidate for LC U. Tokyo Group works on the Full detector simulation of the SI central tracker In our simulation, we use GEANT4 Full detector simulation + tracker hit position smearing Assuming NLC-SD detector parameters (SDMar01): 5 double-sided Si m-strip layers R = 20cm - 125 cm B = 5.0 Tesla Track finding … cheater (gathering hits from the same particle) Track fitting … Using Kalman Filter (implemented by T.Abe)

5. Silicon Central Tracker

6. Tracker Hit Occupancy e+e- tt  6 Jets, s=500 GeV, noISR, no beamstrahlung (strip pitch size * length) 10-310-2at inner most

7. Track Reconstruction Efficiency (Central tracker + VXD) • - - #hit1 in central • & #VXD hit=5 • - - #hit2 in central • & #VXD hit=5 - - - #hit3 in central - - - #hit=5 in central |cosq|<0.8 Vertex Detector linking is important to reconstruct low-P tracks

8. Momentum resolution Generate single particle at |cosq| = 0

9. Photon BG from IR region (from beamstrahlung) We use the g BG data made by T. Maruyama Energy distribution for BG photon from IR SDMar01 Tracker region: 180 photons / bunch  180*190 = ~34000 g/event Ave. Energy = 1.0 MeV (Peak at 0.511MeV  positron annihilation) We input this g data go through GEANT4 detector simulation

10. BG photon detector simulation using GEANT4 (input ~34000 g/event) *On average, ~2000 g/event make hits in a SI tracker *Ave. Energy of the photons which make hits in a tracker = 0.7 MeV *Assuming 50mm*20cm strip : one g makes 1.04 hits in average (Note: Hits which are seen between layers are from End-cap )

11. Tracker Hit Occupancy Signal: e+e- tt 6 Jets, s=500 GeV, noISR, no beamstrahlung Due to the g BG, occupancy increases by an order of magnitude .. But still 1% level at inner most (for 50mm*20cm)

12. GEANT4 Beam Delivery System simulation study at Tokyo K. Tanabe (JLC Road Map report design) • Currently we have outputs (ROOT) • Using this BDS simulation, we’re going to do more detail detector BG studies

13. 2) Si m-strip intermediate tracker R&D • H. Park (KNU), I.H. Park (Ewha U.), • H.J. Kim (Yonsei U.), • J.S.Kang, HC Ha (Korea U.) • 1. Simulation • 2. Design and Fabrication • 3. Measurements • 4. Applications in LC

14. Intermediate Tracker • Require good σrΦ and σz • Reasonable (moderate) cost

15. CDC, 50 wires Support Tube IT, 5 layers VTX, 4 layers Beam pipe e- e+ Application in LC: Intermediate Tracker • 5 layers at r=9 to 37 cm • angular coverage: |cosΘ|<0.9 • spatial resolution: σ = 40μm • thickness of a layer: 0.6% radiation length

16. Momentum Resolution • Full detector simulation • 1 GeV single muon: • reconstruction including energy loss and multiple scattering

17. Effect of Spatial resolution is dominant Multiple scattering, dominant Momentum Resolution - as function of spatial resolution for different energies of the incident particle

18. Current P+ 0.6um (1,1,1) 5 kWN-type N+1.0um High Energy Particle Floating Vf Vf Floating Metal Metal Metal Metal Oxide Oxide P+ P+ P+ P+ 50mm 100mm N-sub N-sub Design/Simulation/Fabrication of Si PIN diode Clean wafer Oxidation N+Diffusion Cover with photoresist Expose through mask Develop Etch, Stip P+ImplantationAnneal Metallization

19. 30um 10um Design and Fabrication •wafer (500/625/380 m) - n-type highresistivity - (111) orientation -single side polished - A pad size : 1.5 x 1.4 cm2

20. Leakage Current Measurement 176nA 68nA Leakage current : 70nA/1cm2 at 250V

21. Assembly: Ladder

22. Dark box sensor Photodiode Pb Pb Beta (90Sr) source S/N Ratio Measurement

24. Heavy Ion Beam with A/Z=2, E=30GeV

25. Silicon Sensor vs dE/dx Correlation

26. Design of Si Strip

27. 20000um 700um 700um 200 200 100 200 200 250 Al SiO2 0.4um 50um 100um n-type wafer 300um For metal contact (n+) 0.4um Aluminum 0.3um Design of Si Strip

28. Summary 1) Si m-strip central tracker Using GEANT4, full simulation studies have been done * Several basic parameters are studied … Vertex Detector Linking is important to reconstruct low-momentum tracks under the high magnetic field * Estimated the photon BG from IR-region … We are also working for the IR/beam-delivery system simulation using GEANT4 at Tokyo  useful for the detail BG study in Si tracker * Track-fitting.. Use Kalman filter * Track-finding.. Not yet Need to be implemented

29. 2) Si m-strip intermediate tracker * Korean group is accumulating knowHow of SI detector * Korean group fabricated SI detector and test results showed that it is as good as others * Submitted R&D proposal for SSD in LC * Apply/extend to silicon detector (Intermediate tracker, Calorimetry) in LC * Need study momentum resolution vs # of layers, thickness, ……