1. BESIII端盖TOF升级 MRPC性能测试
第二次微结构气体探测器研究研讨会
Beijing, China, Jan. 5-6, 2012
BESIII端盖TOF升级 MRPC性能测试
Yongjie Sun
Center of Particle Physics and Technology
University of Science and Technology of China

2. BESIII ETOF MRPC Beam Test
Outline
Introduction
Beam test of the MRPC Prototypes
two-end readout MRPC
single-end readout MRPC
Summary and outlook
2019/5/30
BESIII ETOF MRPC Beam Test

3. Current ETOF and upgrade Target
μ: 110ps
Electron: 148ps
π: 138ps (average 1.1GeV for 2 σ π/K separation, but varying is from 0.9 to 1.3 GeV)
MRPC ETOF
Not too affected by scattering
Total <80ps
Non-intrinsic: 50ps
MRPC: 50ps
>1.4GeV for 2 σ π/K separation
The drawings are from Sun SS calibration result for almost all present data
The red line is representing the time resolution
of 80ps X3.38, that is 95% confidence level
2019/5/30
BESIII ETOF MRPC Beam Test

4. BESIII ETOF MRPC Beam Test
The conceptual design
36-overlapping modules for each E-cap
Module shape: trapezium
Gas gap: 2×6×0.22mm, in 2 stacks
Total thickness: < 25mm
(including gas box and hold structure)
Readout: single / two ends
Strips: 2.5cm wide, 8.6 – 14.1cm long
4mm wide gap between strips
24 channels for each module
4mm
8.6cm
14.1cm
2.5cm
2019/5/30
BESIII ETOF MRPC Beam Test

5. BESIII ETOF MRPC Beam Test
Beam test at BEPC E3 line
~600MeV/c Proton / Pion π p
Electronics: NINO+HPTDC
Work gas: 90%Freon+5%i-C4H10+5%SF6
Goals of the test:
Joint performance test: 50 ps ?
Readout method study:
single or two ends readout ?
Strip length dependence ?
At 600MeV/c, π is Minimum Ionization Particle, p is not.
π / p can be identified by the charge spectrum of T1 or T2.
Proton events were used for better statistics.
2019/5/30
BESIII ETOF MRPC Beam Test

6. Two-end readout: HV Scan
Proton
different particles' efficiency plateau
HV>=6.8kV:
Time resolution: <45ps
For Proton: HV>=6.4kV, efficiency>98%
For Pion: HV>=7.0kV, efficiency>98%
2019/5/30
BESIII ETOF MRPC Beam Test

7. Two-end readout: FEE Threshold Scan
Proton
Time Resolution: <45ps
For Th>150mV:
time resolution changes little with threshold increase
2019/5/30
BESIII ETOF MRPC Beam Test

8. Two-end readout: Pad Scan
Proton 1 12
Time resolution:<45ps
Strip length independent.
2019/5/30
BESIII ETOF MRPC Beam Test

9. Single-end readout MRPC
Beam
Two single-end readout MRPC prototypes were tested together to compare their performance.
2019/5/30
BESIII ETOF MRPC Beam Test

10. Single-end readout: HV Scan
For proton: HV>=5.8kV,efficiency>98%
For Pion:
HV>=6.6kV,efficiency>98%
different particles' efficiency plateau
2019/5/30
BESIII ETOF MRPC Beam Test

11. HV Scan results: comparison
Proton
Single-end readout time resolution: < 50ps ( trigger witdth = 2cm
 intrinsic: ~40ps )
Under work HV:
two-end readout shows better time resolution than single-end readout
(without T-P correction).
Two-end readout need
higher work HV.
2019/5/30
BESIII ETOF MRPC Beam Test

12. Single-end readout: cross-pad scan
trigger size: 5×2 cm2 1 2 3 4 5 6 7 8 9 10 11 12
The boxes represent the hit positions.
2019/5/30
BESIII ETOF MRPC Beam Test

13. Single-end readout: cross-pad scan
Proton
Two prototypes have similar performance.
Pad7 shows better time resolution than pad1/pad12.
Strip length seems affect the time resolution of single-end readout.
2019/5/30
BESIII ETOF MRPC Beam Test

14. Single-end readout: along pad6 scan1 2 3 4 5 6 7 8 9 10 11 12
Hit area: 5×2 cm2
The boxes represent the hit positions.
Scan step:1 cm.
2019/5/30
BESIII ETOF MRPC Beam Test

15. Single-end readout: along pad6 scan
Proton
Time resolution:<50ps
Hit postion(along pad6) seems affect single-end readout time resolution.
2019/5/30
BESIII ETOF MRPC Beam Test

16. Single-end readout: along pad11 scan
Hit area: 5×2 cm2 1 2 3 4 5 6 7 8 9 10 11 12
The boxes represent the hit positions
Scan step:1cm.
2019/5/30
BESIII ETOF MRPC Beam Test

17. Single-end readout: along pad11 scan
Proton
Pad11 time resolution is not as good as pad6 in overall.
For pad11, the influence of hit position is not so clear.
2019/5/30
BESIII ETOF MRPC Beam Test

18. BESIII ETOF MRPC Beam Test
Summary and outlook
Three MRPC prototypes show very good performance
Two-end readout:
time resolution (proton): <45ps
efficiency: >98%
Single-end readout:
the two prototypes almost have the same performance
time resolution(proton): ~50ps (without T-P correction)
efficency: >98%
Two-end readout: strip length does not affect the time resolution
Single-end readout: strip length has some relation with the time resolution
Due to the hit position uncertainty is less, the time resolution of two-end readout is better than single-end readout.
MRPC: main performance satisfy ETOF upgrade requirements.
More specific work needed to improve the performance.
Thank you
2019/5/30
BESIII ETOF MRPC Beam Test

19. Comparison between proton and pion
At 600MeV/c:
proton time resolution is systematically better than pion (MIP)
2019/5/30
BESIII ETOF MRPC Beam Test

20. BESIII ETOF MRPC Beam Test
2019/5/30
BESIII ETOF MRPC Beam Test