1 Beam Test Results of USTC LMRPC modules (50cm) Yongjie Sun presnted by Hongfang Chen

2 Outline  Long-strip MRPC structure  Results of August beam test at GSI  Summary

3 MRPC structure (endview) 5 x 250μm gaps Readout strips HV 2.5cm Readout strips: 2.5 cm x 50 cm HV electrode: Licron spray ~40 M Ω/ □ Made of window glass of 0.7 mm thick

4 MRPC #1 (topview) 55 cm 24.1cm 2.5cm 0.6cm Gaps between strips: 0.6 cm

5 MRPC #2 (topview) Top/bottom pcb The readout strips are “ hollowed-out ” alternately. Removed: 5 mm x 4 Left: 1 mm x 5 Removed: 2.5 mm x 9 Left: 0.25 mm x 10

6 MRPC #3 (topview) 55 cm 24.1cm 2.5cm 0.7cm Gaps between strips: 0.7 cm (upper part) 0.8 cm (lower part) 0.8cm

7 6m Setup Proton Beam Pb 2m 42 cm PMT 1,2 PMT 3,4 PMT 5,6 TSU MRPC USTC MRPC Platform x y

8 Photo of the setup

9 DAQ Logic TDCTDC QDCQDC PMT 1-4(5) Discriminator NIM  ECLVULOM, Logic Delay NIM  ECL LMRPC 1-6 (left) 7-12(right) FEE DelayDiscriminatorNIM  ECL Delay Gate Trigger area: 2 cm x 4 cm (without back_scint.) STOP

10 ADC 1 ADC 2 ADC 3 ADC 4 PMT calibration ADC 1 ADC 2 ADC 3 ADC 4

11 ((t 3 +t 4 )-(t 1 +t 2 ))/4 Resolution~67 ps

12 T-(t1+t2+t3+t4)/4 ADC ADC MRPC Calibration Intrinsic timing resolution = 67 ps (including momentum spread) HV=  7kV

13 Efficiency and resolution plateau 67 ps 97%

14 Position scan (±7 kV) No significant efficiency drop in the gap Trigger Area: 2 cm wide From both “ charge sharing ” and cross talk.

15 Valid TDCs and valid QDCs (3 sigma above pedestal) Valid TDCs Cross Talk MRPC #1 Trigger on the strip center: “ Cross talk ” at neighbor strips: <~3% Trigger Area: 2 cm wide

16 Cross Talk MRPC #2 Valid TDCs and QDCs

17 Efficiency vs. Position MRPC #2 Valid TDCs HV=  7kV

18 Valid TDCs and valid QDCs (3 sigma above pedestal)

19 Cross Talk MRPC #3

20 Efficiency vs. Position MRPC #3 Valid TDCs

21 Track information using the data of SSD the following analysis is based on the instruction of : Y.P. Zhang,P.-A. Loizeau Data structure of final NTUPLE and a short description about how to use the silicon tracking system the data files used : run_0005.root, run_0006.root,......, run_0020.root, where the USTC-MRPC was settled at the same position. run_0021.root, the MRPC moved by 12mm.

22 Hits position profile on MRPC the profile is about 3cm x 2 cm the following analysis will base on these SSD position cuts and charge cuts

23 Tranverse profile-- efficiency vs position for MRPC#1 run

24 Efficiency vs Position for MRPC#1 data file, run_0021.root edge effects 6mm-gap

25 Combined data

26 Summary  The cross talk for neighbour strip ~3% for modules MRPC#1, 2, 3. (50cm strip)  Next step 1m long strip Thank You ！ 谢谢 ！

27

28 Signal Charge vs Position near the edge of stripat the middle of strip

29 Time Resolution of PMT timing ( (t3+t4)-(t1+t2) )/4 after T-A correction Sigma(pmt) = 2.08 *35ps = 73ps

30 RPC time resolution cuts: SSD cust PMT cuts resolution: sigma(rpc) = 69 ps 35ps/ch

31 Hit tranverse profile position distribution

32 pmt resolution vs position ((t3 + t4) - (t1 + t2) )/4

33 rpc

34 rpc resolution vs position

35 eff and reo vs position

36 Longitudinal

37 edge effects the profile is also quite clear, and we can see that the beam hits between two strips of the MRPC

38  (2) pmt cuts:  pmt-pair charge: q1+q2, q3+q4  take out 5% at the low range side, and take another 25% at the high range side  time difference: T1-T2, T3-T4  2.5%, 2.5%  position difference: (T1-T2)-(T3-T4)  2.5%, 2.5%  time of flight: ((T3+T4)-(T1+T2))/4  0.5%, 0.5%

39 edge effects