1. Fast TRD - R&D Status Mihai Petrovici, CBM-Meeting, Feb. 26-29, 2008, GSI Introduction Short review - First HCRTRD prototypes: - MWPC – w & w/o drift zone - GEM - Second HCRTRD prototypes - MWPC – double sided - GEM Counting rate performance: charge pulse height position resolution e/  discrimination Third HCRTRD prototype – real size cell Conclusions B C M

2. Baseline Detector Setup Tracking: STS, TRD Vertexing: STS Hadron ID : TOF Electron ID: RICH, TRD, ECAL γ, n: ECAL The Challenge: very rare probes in Au+Au at reaction rates up to 10 7 events/sec ~ 1000 charged particle/event CBM - TRD Counting rates ~ 10 5 part/sec/cm 2 High granularity -  rej (at 90% e efficiency) > 100

3. First HCRTRD - prototype -type: radiator + MWPC -anode-cathode distance–3 mm -2.5 mm anode pitch - maximum drift time ~ 100 ns - channel size ~ 6 cm 2 1 GeV/c U A = 1900 V Xe,CO 2 (15%) Rohacell

4. ALICE-TRD

5. Readout electrode pad size: 5 x 10 mm 2 Anode 20 μm, WAu 2.5 mm pitch Second HCRTRD - prototype

6. High Counting Rate Effect Xe,CO 2 (15%), p-1.5 GeV/c 1.2 %  6.1 % - 5.1 %  4.3 %

7. Rate Dependence for 30 0 Tilted Chamber 2.5 %  1.2 % 3.4 %  1.2 % 1.2 %  1.2 % 1800 V

8. Rate Dependence of the Position Resolution

10. log(p e /p  )p e /(p e + p  ) 20/500/120  1800 V, foils, ~ 0.7 %  rejection 20/500/120  20/200/220, 1.4 better e/  discrimination performance 1.5 GeV/c

11. e/  discrimination performance 1 GeV/c,U A = 1900 V 1.5 GeV/c,U A = 1800 V Xe,CO2(15%)

12. e/  discrimination performance ALICE - TRD Taku Gunji – ALICE TRD

13.  e e/  discrimination – counting rate dependence

14. TRD based on compact geometry MWPC works up to > 210 5 particles/cm 2 /sec with negligible change of pulse height or charge (~2-3%) The position resolution at low rate is ~160  m; the observed degradation is ~20  m at 210 5 particles/cm2/sec ; A double-sided pad readout electrode brings the performance of these TRD at a  rejection factor of ~200 for 6 layers using appropriate foil stack radiator.  The solution for: -high counting rate - high granularity - high e/  rejection factor - minimum material budget - minimum electronic channels Conclusions

15. Third HCRTRD - prototype

21. Participants NIPNE-Bucharest University of Münster D. Bartos M. Petris M. Hoppe I. Berceanu M. Petrovici A. Wilk V. Catanescu V. Simion J.P. Wessels A. Herghelegiu P. Dima C. Magureanu A. Radu D. Moisa GSI - Darmstadt University of Heidelberg A. Andronic C. Lippmann D. Emschermann P. Braun-Munzinger D. Miskowiecz I. Rusanov C. Garabados R. Simon H.K. Solveit J. Hehner H. Stelzer J. Stachel M. Kalisky F. Uhling University of Frankfurt JINR Dubna H. Appelshäuser V. Babkin V. Golovatiouk S. Chernenko Yu. Zanevsky V. Geger V. Zryuev Double sided read-out pad plane electrode prototype : In beam tests :