1. CBM-Meeting, Darmstadt26-29.02.2008 A.Schüttauf for the FOPI- collaboration FOPIs new MMRPC-barrel

2. CBM-Meeting, Darmstadt26-29.02.2008 Outlook  The MMRPC parameters  Installation of the RPC-barrel  First experiment using the barrel  Results and system performance  Summary and Outlook

3. CBM-Meeting, Darmstadt26-29.02.2008 FOPI ToF Upgrade (Reminder) For high granularities experiments price is an issue. FOPI TOF: Size ~5 m 2 Channels ~ 4800  ToF <100 ps   <0.5 cm Central Au-Au collision at 1.45 AGeV has ~60- particles in the acceptance of the proposed RPC barrel This needs a granularity of 700 cells (2500 strips)

4. CBM-Meeting, Darmstadt26-29.02.2008 MMRPCs production parameters FOPIs MMRPC parameters: 90 x 4.6 cm 2 active area 1.1 & 0.5 mm 10 glass plates 8 x 220 µm gaps (fishing rope) 16 strips 1.64/0.9 mm strip/gap ~9.5 kV applied voltage Gas: C 2 F 4 H 2 /isobutane/SF6 80/5/15 Multi-pin connector Multi-strip anode Capacitor block Glass stack 8 gaps Stesalit support Mounting table MMRPC glass stack

5. CBM-Meeting, Darmstadt26-29.02.2008 FOPIs Super Module (SM) 5 MMRPC in a Super Module (SM) 30 SMs within FOPI Gas box HV-connector Gas in/outlets End-flange 1 MMRPC Interface between MMRPC & Electronics SAMTEC 50 Ω multi-coaxial cable 0.8 mm pitch. In total 80 connections (16 used).

6. CBM-Meeting, Darmstadt26-29.02.2008 Full Readout System FEE5 + TAC/QDC-Digitizer 16 ch. G ~ 160 TAC ~10 ps/ch  f ~ 1.5 GHz Zero-suppression P F ~ 0.56 W/ch P T ~ 0.5 W/ch Full system electronic resolution  E < 25 ps Free running common stop system at 40 MHz. Individual TAC resets 0.033-2.0 µs. Electronic resolution FEE ~ 18 ps TAC ~ 10 ps  t ~ 15 ps TAC < 2 ps + FEE < 3 ps + Card  10 ps + Clock  10 ps   t ~ 15 ps M.Ciobanu, K.Koch

7. CBM-Meeting, Darmstadt26-29.02.2008 Final signal shape for the MMRPC Primary RPC signal The primary charge for a RPC-strip signal is 40-100 fC which is in our case between 1-7 mV. The optimal adaption to 50 Ω leads to a nearly perfect primary signal shape. After amplification (G~160) the signal has a threshold due to rest oscillations from the discriminator of U thr >80 mV Amplified RPC signal

8. CBM-Meeting, Darmstadt26-29.02.2008 MMRPC: Housing & Joining Building Super Module 0 December 2005 K.D.Hildenbrand M.Kis X.Zhang Y.J.Kim

9. CBM-Meeting, Darmstadt26-29.02.2008 Setup for in beam tests with SM0 Front ViewTop View Trigger  PMT1 & PMT2 Efficiency  PMT1 & PMT2 & PMT3 Side View PMT 2PMT 1 PMT 3 RPCs PMT 1PMT 2 PMT 3 Beam , p, d Measurements: Timing, efficiency & cluster size Rate dependence of float glass MRPCs

10. CBM-Meeting, Darmstadt26-29.02.2008 Timing and efficiency for SM0: RPC versus PMT system Our first module (SM0) delivered for E-Fields > 107 kV/cm the following results: Rate 80-150 Hz/cm 2 RPC b + Start σ t < 96 ps Start σ ts < 78 ps RPC σ RPC < 56 ps Efficiency  > 99 %

11. CBM-Meeting, Darmstadt26-29.02.2008 Timing and efficiency for SM0: RPC (b) versus RPC (d) Our first module (SM0) delivered for E-Fields > 107 kV/cm the following results: Rate 80-150 Hz/cm 2 RPC b + RPC d σ t < 84 ps RPC bd \√2 σ RPC < 59 ps Efficiency  > 99 % It confirms the RPC versus PMT measurement within the errors. Both show consistently a time resolution σ RPC < 60 ps.

12. CBM-Meeting, Darmstadt26-29.02.2008 Timing and Efficiency for SM0: At high rates 3-5 kHz/cm 2 Our first module (SM0) delivered for E-Fields > 107 kV/cm the following results: Rate 3-5kHz/cm 2 RPC b + Start σ t < 135 ps Start σ ts < 78 ps RPC σ RPC < 110 ps Efficiency  > 75 % T.I Kang FOPI needs a rate capability between 10-50 Hz/cm 2.

13. CBM-Meeting, Darmstadt26-29.02.2008 Cluster size and charge for SM0 =: Mean number of strips fired for a particle. RMS(nstr) =: Width of the cluster distribution. The cluster size is smaller then 2.5 strips ( ) with a width below 1.5 strips (RMS(nstr)). =: Mean charge for a strip RMS(Q) =: Width of the charge distribution The mean cluster charge and its RMS is nearly linear depended on the electric field.

14. CBM-Meeting, Darmstadt26-29.02.2008 Production of 30 SMs in 2006 All SMs under permanent Ar gas flow All 30 SMs were tested up to 13 kV. In the final measurement regime, between 100-110 kV/cm (8.8-9.6 kV), all SM were below 0.4 Hz/cm 2. Rate Hz/cm 2 E-Field (kV/cm) 0.3 Hz/cm 2

15. CBM-Meeting, Darmstadt26-29.02.2008 FOPIs new ToF-barrel was used during the first Ni+Ni run in Sepember 2007

16. CBM-Meeting, Darmstadt26-29.02.2008 Timing and position resolution for the full system After all corrections the Time of Flight resolution is σ ToF < 95 ps including the start resolution with σ Start < 65-70 ps The final  -resolution is Δ  < 0.14 o which is Δx < 2.5 mm.

17. CBM-Meeting, Darmstadt26-29.02.2008 Cluster size in relation to the energy loss of the particle With the P t cut we select similar angles for the traversing particle in the RPC. The dE/dx is measured by the CDC independently. The RPCs shows a strong cluster size ( ) dependence on the dE/dx. Varying from ~ 2.5 for MIP like particles up to ~ 4.3 for slow particles with high dE/dx. For a high P t and low primary dE/dx We see the expected behavior of ~2.5 Plotting the mean summed RPC charge versus the CDC dE/dx, we see a strong correlation between both measurements.

18. CBM-Meeting, Darmstadt26-29.02.2008 Avalanche size in relation to primary charge and gap thickness Gap size variationPrimary charge variation

19. CBM-Meeting, Darmstadt26-29.02.2008 The final PID performance: v [cm/ns] p [GeV/c] p d t ++ -- K+K+ K-K- K.Piasecki K - - PID: S/B > 10 K-K-

20. CBM-Meeting, Darmstadt26-29.02.2008 How to improve ? Gas mixture Timing:  t = 1.28255/(  -  )v  -  = Effective Townsend coefficient v = Drift velocity I.Deppner

21. CBM-Meeting, Darmstadt26-29.02.2008 GSI-FOPI : K.Hildenbrand T.I.Kang Y.J.Kim M.Kis P.Koczon Y.Leifels M.Marquardt W.Reisdorf M.S.Ryu A.Schüttauf J.Weinert X.Zhang N.Zernezki GSI-EE E.Badura R.Hardel K.Koch N.Kurz W.Ott R.Schulze HD-University M.Ciobanu I.Deppner A.Reischl K.Piasetzki N.Herrmann NIPNE, Bucharest M.Petrovici V.Simion People: Summary: Our final electronic resolution is  E <25 ps for the final system. R&DTiming SM0: A) Single hits MMRPC  t <48 ps (RPC) B) Single hits MMRPC  t <55 ps (RPC+E.) C) Single hits MMRPC  t <85 ps (Full) Efficiency: A)Single hits  > 99% Full system performance (2200 strips): Timing A) Single hits MMRPC  t <60 ps (RPC) B) Single hits MMRPC  t <65 ps (RPC+E.) C) Single hits MMRPC  t <95 ps (Full) Efficiency: A) Single hits  > 95% Cluster size: Is bigger than expected ~ 2.5-4.0 and depending on the dE/dx of the particle. It’s ~2-2.5 for MIPs. PID: K - pid is possible with a S/B =10/1 Korea University, Seoul B.Hong Conclusion: FOPI successfully commissioned the new MMRPC-barrel which can now be used for the anticipated physics program.

22. CBM-Meeting, Darmstadt26-29.02.2008 Future developments at the GSI/FAIR facility for the CBM-ToF M.Ciobanu M.Kis A.Schuettauf An ASIC based Preamplifier Discriminator (PADI) for the CBM-TOF system

23. CBM-Meeting, Darmstadt26-29.02.2008 ToF, dE/dx, Kaon iD

24. CBM-Meeting, Darmstadt26-29.02.2008

25. CBM-Meeting, Darmstadt26-29.02.2008 Q/A:  -tests for all SM Test setup for gamma-ray test High voltage: 9.5 kV Gas flow : 2-3 days Hit rate: 50-70 Hz/counter Timing resolution: σ TOF < 150-250 ps The results of SM17 for the gamma

26. CBM-Meeting, Darmstadt26-29.02.2008 Q/A: Dark-rate measurements E-Field kV/cm Rate Hz/cm 2 E-Field kV/cm Rate Hz/cm 2 X.Zhang

27. CBM-Meeting, Darmstadt26-29.02.2008 Signal

28. CBM-Meeting, Darmstadt26-29.02.2008 Final SM for the installation into FOPI 9.5 kV

29. CBM-Meeting, Darmstadt26-29.02.2008 Multi-strip-MRPC (MMRPC)

30. CBM-Meeting, Darmstadt26-29.02.2008 dE/dx dependence of RPCs

31. CBM-Meeting, Darmstadt26-29.02.2008

32. CBM-Meeting, Darmstadt26-29.02.2008