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A solution for the inner area of CBM-TOF with pad-MRPC
Nuclear Instruments and Methods in Physics Research A ∎ (∎∎∎∎) ∎∎∎–∎∎∎
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A solution for the inner area of CBM-TOF with pad-MRPC Y. Wang a, X.J. Huang a,n, P.F. Lyu a, D. Han a, B. Xie a, Y.J. Li a, N. Herrmann b, I. Deppner b, P. Loizeau b, C. Simon b, J. Frühauf c, M. Kiš c a Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education Department of Engineering Physics, Tsinghua University, Beijing 100084, China b Physikalisches Institute, University Heidelberg, Heidelberg, Germany c GSI Helmholtzzentrum fr Schwerionenforschung, GSI, Damstadt, Germany
art ic l e i nf o
a b s t r a c t
Article history: Received 15 March 2016 Received in revised form 27 June 2016 Accepted 29 June 2016
The Compressed Baryonic Matter (CBM) experiment has decided to use the Multi-gap Resistive Plate Chambers(MRPC) technology to build its Time-Of-Flight (TOF) wall. CBM-TOF requires a rate capability over 20 kHz/cm2 for inner region. A 10-gap pad-MRPC assembled with low resistive glass is designed to construct this area. The prototypes, which consist of 10 0.22 mm gas gaps and 2 8 20 mm 20 mm readout pads, require fewer electronic channels compared to the strip design. A timing resolution of around 60 ps and an efficiency above 98% were obtained in a cosmic test and a beam test taken in 2014 October GSI beam time. The results show that the real-size prototypes fulfill the requirements of the CBM-TOF. & 2016 Elsevier B.V. All rights reserved.
Keywords: CBM-TOF Pad-MRPC Beam test High rate Timing resolution
1. Introduction The Compressed Baryonic Matter (CBM) experiment, which aimed at the exploration of the QCD phase diagram in the region of high baryon densities using heavy-ion collisions, will be one of the four major scientific pillars of Facility for Antiproton and Ion Research (FAIR). The Time-of-Flight (TOF) system is one of the core detectors of the CBM experiment. It will provide particle identification for all charged hadrons produced in beam–target interactions and emitted to polar angles from 2.5° to 25°. The TOF wall, which will be located between 6 m and 10 m from the target depending on the physics needs, is 9 m in height and 13 m in width and covers an active area of about 120 m2 [1]. To separate hadrons with a momentum up to a few GeV/c, a TOF timing resolution of 80 ps at high efficiency is required according to simulations [2]. In the current design, the TOF wall is divided into four rate regions. The simulated particle flux ranges from 8 kHz/cm2 to 25 kHz/cm2 for the innermost region, and falls down to 500 Hz/cm2 in the outmost region [3], as shown in Fig. 1. The Multi-gap Resistive Plate Chambers(MRPC) technology, with the advantages of good timing resolution, high detection efficiency and relatively low cost [4], is considered as a good solution that can meet the requirements of CBM-TOF [1]. However, n
Corresponding author. E-mail address: [email protected] (X.J. Huang).
the MRPC assembled with float glass can only achieve a rate capability of hundreds of Hz/cm2 [5]. Tsinghua University had successfully developed a low resistivity glass with a resistivity on the order of 1010 Ω cm [6]. MRPC assembled with this kind of low resistivity glass can keep their performance at a flux rate up to 60 kHz/cm2 [7]. A simulation study indicated that a MRPC based on low resistivity glass with small readout pads can efficiently cope with a high flux rate of about 20 kHz/cm2 [7]. Thus padMRPC prototypes for the center region of CBM-TOF were designed and produced. In this paper the structure and the test results of the pad-MRPC prototypes are presented. The cosmic test was performed at Tsinghua. The beam test was performed at 2014 October GSI beam time. Secondary particles from a 152Sm beam hitting on a Pb target were used.
2. Module structure Real size MRPC prototypes with an active area of 176 mm 42 mm which are subdivided into sixteen 20 mm 20 mm readout pads with an 2 mm interval between pads were developed and were arranged into a double stack configuration with gas gaps of 10 0.22 mm, defined by nylon fish line. The thickness of outer glass is 1 mm and thickness of inner glass is 0.7 mm. Fig. 2 provides a schematic structure of the
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Please cite this article as: Y. Wang, et al., Nuclear Instruments & Methods in Physics Research A (2016), http://dx.doi.org/10.1016/j. nima.2016.06.133i
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Y. Wang et al. / Nuclear Instruments and Methods in Physics Research A ∎ (∎∎∎∎) ∎∎∎–∎∎∎
Fig. 3. A schematic view of a cosmic test system.
be presented in this section. A HV of 6 kV was applied and PADI electronics was used in the tests [10]. 3.1. Cosmic test Fig. 1. Simulated particle flux rate on the TOF wall. The TOF wall is separated into four regions with similar flux.
A cosmic test system was set up in our lab at Tsinghua. Fig. 3 left gives a schematic view of the cosmic test system. Where PMT 0 acts as trigger, PMTs 1–4 provide the timing reference and PMT 5, PMT 6 provide the efficiency reference. Three pad-MRPC modules were test in this system. Fig. 4 shows the timing difference between tested module MRPC3 and PMT reference. Each bin represents 25 ps and the reference timing resolution is 63 ps. The MRPC3 timing resolution was thus (3.577*25)2 − 632 = 63.3 ps. Table 1 summarizes the performance of the MRPC modules studied in the cosmic test. 3.2. Beam test The pad-MRPC prototypes were tested in the 2014 October GSI beam time using the secondary particles from a 152Sm beam hitting on a Pb target. Fig. 5 provides the layout of the beam test. The pad-MRPC modules and a thin strip MRPC module BucRef are the target detectors. The coincidence signal of the diamond detector and a target detector is used as the trigger of the DAQ system. And the two PMTs provide the flux rate measurement. A flux rate of
Fig. 2. A schematic structure of the pad readout MRPC.
module. Compared with the thin strip MRPC design for inner region of CBM-TOF, the pad-MRPC has advantages of requiring less electronic channels and supposed to have a smaller cluster size.
3. Detector performance and tests The MRPC modules with same glass material and same gas gap width were tested at IHEP, March, 2013. The HV scan was taken under a low flux rate. And a timing resolution of 45 ps and a efficiency of 98% was obtained when the applied HV is higher than 5.8 kV [8]. An aging test which measured the performance of the prototypes using cosmic ray while irradiated by X-rays was also taken. No obvious performance degradation was observed after 0.1 C/cm2 charge was accumulated [9]. The test results of a cosmic test and a beam test taken in the 2014 October GSI beam time will
Fig. 4. The timing difference between tested module MRPC 4 and PMT timing reference. The curve is a Gaussian fit to the distribution to obtain the total MRPCþ ref timing resolution.
Please cite this article as: Y. Wang, et al., Nuclear Instruments & Methods in Physics Research A (2016), http://dx.doi.org/10.1016/j. nima.2016.06.133i
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Table 1 Performance of Pad-MRPC prototype for CBM-TOF in cosmic test. Module Efficiency (%) Timing resolution (ps)
Dark rate (Hz/ cm2)
Cluster size
MRPC1 MRPC2 MRPC3
0.57 0.53 0.61
1.23 1.30 1.27
98.4 98.6 98.2
56.1 58.7 63.3
Fig. 5. Schematic diagram of the beam test at GSI, October 2014. 2
several hundreds Hz/cm was obtained in this beam test. The calibration was done by CBM-root and a program developed by Tsinghua group. The pad-MRPC and BucRef were used to calibration each other, and the diamond detector was used as a second reference. The fastest tdc from each detector in a cluster was selected. In Tsinghua's program, in the first step the relative offsets between each pad/strip and the diamond detector were extracted and removed. The second step was velocity correction. When the speed of particle is higher, its time of flight between diamond detector and pad-MRPC, and between pad-MRPC and BucRef will be smaller. And the speed limit it can approach is the speed of light. Fig. 6 provides an example of velocity correction. The ΔT = tdcpad − tdcBucRef versus ΔTdia = tdccpad − tdccdiamond are plotted, and the Gaussian means of each ΔTdia bin are fitted with a piecewise function. The velocity correction was done by subtracting this piecewise function. The third step was the slewing correction, which removed the ΔT jitter caused by different signal amplitudes. Fig. 7 shows an example of ΔT –TOT correlation and the fitted correction curve, where the TOT is the time over threshold of the MRPC signal, which represents the signal amplitude. The ΔT versus TOT are plotted, and the Gaussian means of each TOT bin are fitted with a 3rd-order polynomial. The slewing correction was done by subtracting this 3rd-order polynomial and was done to both pad-MRPC and BucRef in 3 loops. Fig. 8 shows a Gaussian fit to the ΔT distribution after all correction, implies a total timing resolution of about 95 ps for pad-MRPC þ BucRef, and 95/ 2 = 67 ps for single detector. The efficiency calculated by CBM-root for this dataset is 98.2%. The data was also used to build clusters to measure the crosstalk in chambers. The connected fired pads were required in cluster construction. The cluster size is 1.78 for pad-MRPC and 3.02 for BucRef, the cluster size distribution for pad-MRPC is shown in Fig. 9.
Fig. 7. An example of slewing correction curve, the Gaussian mean ΔT as a function of TOT. The curve is a third order polynomial fit to the data points.
Fig. 8. The ΔT distribution after all correction. The curve is a Gaussian fit to the distribution to obtain the pad-MRPC þ BucRef timing resolution.
Fig. 9. The cluster size distribution of pad-MRPC.
Fig. 6. An example of velocity correction curve, the Gaussian mean ΔT as a function of ΔTdia . The curve is a piecewise function fit to the data points.
To reduce the impact from clustering and investigate the timing ability difference between the two tested detectors, a single-hit event study was done. A single-hit event for pad-MRPC/BucRef means there is only one pad/strip fired in this event. The single-hit events for pad-MRPC/BucRef were selected and the calibration procedure was done to a single pad and strip again. Fig. 10 shows the result of single-hit events study. The up left plot is for all events, the ΔT distribution goes wider since not the fastest tdcs but the tdcs of a specific pad/strip are selected. The up right plot shows the single-hit event for pad, the timing resolution does not change much. The down left plot is for single-hit event for BucRef and the timing resolution improves a lot. The down right plot is for single-hit event for both pad-MRPC and strip, the timing
Please cite this article as: Y. Wang, et al., Nuclear Instruments & Methods in Physics Research A (2016), http://dx.doi.org/10.1016/j. nima.2016.06.133i
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Fig. 10. The ΔT distribution of different events in single-hit events study. The up left plot is for all events, the up right plot shows the single-hit event for pad, the down left plot is for single-hit event for BucRef and the down right plot is for single-hit event for both pad-MRPC and BucRef.
resolution is 87/ 2 = 62 ps for single detector. This study implies that the BucRef suffers more form clusters and pad-MRPC may have a better timing resolution for all events.
of China (11420101004, 11461141011, 11275108) and supported by the Ministry of Science and Technology under Grant no. 2015CB856905. We also thank the CBM Collaboration for their support.
4. Conclusion Real size MRPC prototypes have been developed for CBM-TOF inner region. The prototypes assembled with low resistive glass have 10 0.22 mm gas gaps. The active area of the prototypes is 176 mm 42 mm, which is sub-divided into sixteen 20 mm 20 mm readout pads with an 2 mm interval between pads. A timing resolution around 60 ps and an efficiency of over 98% were obtained in a cosmic test and a beam test at GSI. The results show that the real-size prototypes fulfill the requirements of the CBM-TOF.
References [1] Technical Design Report for the CBM Time-of-Flight System: 〈http://repository. gsi.de/record/109024/files/tof-tdr-final_rev6036.pdf〉. [2] I. Deppner, et al., J. Instrum. 7 (10) (2012) C10014. [3] I. Deppner, et al., Nucl. Instrum. Methods Phys. Res. Sect. A 661 (2012) 121. [4] A.N. Akindinov, et al., Nucl. Instrum. Methods Phys. Res. Sect. A 533 (2004) 74. [5] E.C. Zeballos, et al., Nucl. Instrum. Methods Phys. Res. Sect. A 374 (1996) 132. [6] Y. Wang, et al., J. Instrum. 9 (8) (2014) C08003. [7] J.B. Wang, et al., Nucl. Instrum. Methods Phys. Res. Sect. A 713 (2013) 40. [8] W.P. Zhu, et al., Nucl. Instrum. Methods Phys. Res. Sect. A 56.11 (2013) 2821. [9] J. Wang, et al., Online aging study of high rate MRPC: arXiv:1508.03394. [10] M. Ciobanu, et al., Proc. IEEE (2009) 401.
Acknowledgments This work is supported by National Natural Science Foundation
Please cite this article as: Y. Wang, et al., Nuclear Instruments & Methods in Physics Research A (2016), http://dx.doi.org/10.1016/j. nima.2016.06.133i
Contents lists available at ScienceDirect
Nuclear Instruments and Methods in Physics Research A journal homepage: www.elsevier.com/locate/nima
A solution for the inner area of CBM-TOF with pad-MRPC Y. Wang a, X.J. Huang a,n, P.F. Lyu a, D. Han a, B. Xie a, Y.J. Li a, N. Herrmann b, I. Deppner b, P. Loizeau b, C. Simon b, J. Frühauf c, M. Kiš c a Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education Department of Engineering Physics, Tsinghua University, Beijing 100084, China b Physikalisches Institute, University Heidelberg, Heidelberg, Germany c GSI Helmholtzzentrum fr Schwerionenforschung, GSI, Damstadt, Germany
art ic l e i nf o
a b s t r a c t
Article history: Received 15 March 2016 Received in revised form 27 June 2016 Accepted 29 June 2016
The Compressed Baryonic Matter (CBM) experiment has decided to use the Multi-gap Resistive Plate Chambers(MRPC) technology to build its Time-Of-Flight (TOF) wall. CBM-TOF requires a rate capability over 20 kHz/cm2 for inner region. A 10-gap pad-MRPC assembled with low resistive glass is designed to construct this area. The prototypes, which consist of 10 0.22 mm gas gaps and 2 8 20 mm 20 mm readout pads, require fewer electronic channels compared to the strip design. A timing resolution of around 60 ps and an efficiency above 98% were obtained in a cosmic test and a beam test taken in 2014 October GSI beam time. The results show that the real-size prototypes fulfill the requirements of the CBM-TOF. & 2016 Elsevier B.V. All rights reserved.
Keywords: CBM-TOF Pad-MRPC Beam test High rate Timing resolution
1. Introduction The Compressed Baryonic Matter (CBM) experiment, which aimed at the exploration of the QCD phase diagram in the region of high baryon densities using heavy-ion collisions, will be one of the four major scientific pillars of Facility for Antiproton and Ion Research (FAIR). The Time-of-Flight (TOF) system is one of the core detectors of the CBM experiment. It will provide particle identification for all charged hadrons produced in beam–target interactions and emitted to polar angles from 2.5° to 25°. The TOF wall, which will be located between 6 m and 10 m from the target depending on the physics needs, is 9 m in height and 13 m in width and covers an active area of about 120 m2 [1]. To separate hadrons with a momentum up to a few GeV/c, a TOF timing resolution of 80 ps at high efficiency is required according to simulations [2]. In the current design, the TOF wall is divided into four rate regions. The simulated particle flux ranges from 8 kHz/cm2 to 25 kHz/cm2 for the innermost region, and falls down to 500 Hz/cm2 in the outmost region [3], as shown in Fig. 1. The Multi-gap Resistive Plate Chambers(MRPC) technology, with the advantages of good timing resolution, high detection efficiency and relatively low cost [4], is considered as a good solution that can meet the requirements of CBM-TOF [1]. However, n
Corresponding author. E-mail address: [email protected] (X.J. Huang).
the MRPC assembled with float glass can only achieve a rate capability of hundreds of Hz/cm2 [5]. Tsinghua University had successfully developed a low resistivity glass with a resistivity on the order of 1010 Ω cm [6]. MRPC assembled with this kind of low resistivity glass can keep their performance at a flux rate up to 60 kHz/cm2 [7]. A simulation study indicated that a MRPC based on low resistivity glass with small readout pads can efficiently cope with a high flux rate of about 20 kHz/cm2 [7]. Thus padMRPC prototypes for the center region of CBM-TOF were designed and produced. In this paper the structure and the test results of the pad-MRPC prototypes are presented. The cosmic test was performed at Tsinghua. The beam test was performed at 2014 October GSI beam time. Secondary particles from a 152Sm beam hitting on a Pb target were used.
2. Module structure Real size MRPC prototypes with an active area of 176 mm 42 mm which are subdivided into sixteen 20 mm 20 mm readout pads with an 2 mm interval between pads were developed and were arranged into a double stack configuration with gas gaps of 10 0.22 mm, defined by nylon fish line. The thickness of outer glass is 1 mm and thickness of inner glass is 0.7 mm. Fig. 2 provides a schematic structure of the
http://dx.doi.org/10.1016/j.nima.2016.06.133 0168-9002/& 2016 Elsevier B.V. All rights reserved.
Please cite this article as: Y. Wang, et al., Nuclear Instruments & Methods in Physics Research A (2016), http://dx.doi.org/10.1016/j. nima.2016.06.133i
2
Y. Wang et al. / Nuclear Instruments and Methods in Physics Research A ∎ (∎∎∎∎) ∎∎∎–∎∎∎
Fig. 3. A schematic view of a cosmic test system.
be presented in this section. A HV of 6 kV was applied and PADI electronics was used in the tests [10]. 3.1. Cosmic test Fig. 1. Simulated particle flux rate on the TOF wall. The TOF wall is separated into four regions with similar flux.
A cosmic test system was set up in our lab at Tsinghua. Fig. 3 left gives a schematic view of the cosmic test system. Where PMT 0 acts as trigger, PMTs 1–4 provide the timing reference and PMT 5, PMT 6 provide the efficiency reference. Three pad-MRPC modules were test in this system. Fig. 4 shows the timing difference between tested module MRPC3 and PMT reference. Each bin represents 25 ps and the reference timing resolution is 63 ps. The MRPC3 timing resolution was thus (3.577*25)2 − 632 = 63.3 ps. Table 1 summarizes the performance of the MRPC modules studied in the cosmic test. 3.2. Beam test The pad-MRPC prototypes were tested in the 2014 October GSI beam time using the secondary particles from a 152Sm beam hitting on a Pb target. Fig. 5 provides the layout of the beam test. The pad-MRPC modules and a thin strip MRPC module BucRef are the target detectors. The coincidence signal of the diamond detector and a target detector is used as the trigger of the DAQ system. And the two PMTs provide the flux rate measurement. A flux rate of
Fig. 2. A schematic structure of the pad readout MRPC.
module. Compared with the thin strip MRPC design for inner region of CBM-TOF, the pad-MRPC has advantages of requiring less electronic channels and supposed to have a smaller cluster size.
3. Detector performance and tests The MRPC modules with same glass material and same gas gap width were tested at IHEP, March, 2013. The HV scan was taken under a low flux rate. And a timing resolution of 45 ps and a efficiency of 98% was obtained when the applied HV is higher than 5.8 kV [8]. An aging test which measured the performance of the prototypes using cosmic ray while irradiated by X-rays was also taken. No obvious performance degradation was observed after 0.1 C/cm2 charge was accumulated [9]. The test results of a cosmic test and a beam test taken in the 2014 October GSI beam time will
Fig. 4. The timing difference between tested module MRPC 4 and PMT timing reference. The curve is a Gaussian fit to the distribution to obtain the total MRPCþ ref timing resolution.
Please cite this article as: Y. Wang, et al., Nuclear Instruments & Methods in Physics Research A (2016), http://dx.doi.org/10.1016/j. nima.2016.06.133i
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Table 1 Performance of Pad-MRPC prototype for CBM-TOF in cosmic test. Module Efficiency (%) Timing resolution (ps)
Dark rate (Hz/ cm2)
Cluster size
MRPC1 MRPC2 MRPC3
0.57 0.53 0.61
1.23 1.30 1.27
98.4 98.6 98.2
56.1 58.7 63.3
Fig. 5. Schematic diagram of the beam test at GSI, October 2014. 2
several hundreds Hz/cm was obtained in this beam test. The calibration was done by CBM-root and a program developed by Tsinghua group. The pad-MRPC and BucRef were used to calibration each other, and the diamond detector was used as a second reference. The fastest tdc from each detector in a cluster was selected. In Tsinghua's program, in the first step the relative offsets between each pad/strip and the diamond detector were extracted and removed. The second step was velocity correction. When the speed of particle is higher, its time of flight between diamond detector and pad-MRPC, and between pad-MRPC and BucRef will be smaller. And the speed limit it can approach is the speed of light. Fig. 6 provides an example of velocity correction. The ΔT = tdcpad − tdcBucRef versus ΔTdia = tdccpad − tdccdiamond are plotted, and the Gaussian means of each ΔTdia bin are fitted with a piecewise function. The velocity correction was done by subtracting this piecewise function. The third step was the slewing correction, which removed the ΔT jitter caused by different signal amplitudes. Fig. 7 shows an example of ΔT –TOT correlation and the fitted correction curve, where the TOT is the time over threshold of the MRPC signal, which represents the signal amplitude. The ΔT versus TOT are plotted, and the Gaussian means of each TOT bin are fitted with a 3rd-order polynomial. The slewing correction was done by subtracting this 3rd-order polynomial and was done to both pad-MRPC and BucRef in 3 loops. Fig. 8 shows a Gaussian fit to the ΔT distribution after all correction, implies a total timing resolution of about 95 ps for pad-MRPC þ BucRef, and 95/ 2 = 67 ps for single detector. The efficiency calculated by CBM-root for this dataset is 98.2%. The data was also used to build clusters to measure the crosstalk in chambers. The connected fired pads were required in cluster construction. The cluster size is 1.78 for pad-MRPC and 3.02 for BucRef, the cluster size distribution for pad-MRPC is shown in Fig. 9.
Fig. 7. An example of slewing correction curve, the Gaussian mean ΔT as a function of TOT. The curve is a third order polynomial fit to the data points.
Fig. 8. The ΔT distribution after all correction. The curve is a Gaussian fit to the distribution to obtain the pad-MRPC þ BucRef timing resolution.
Fig. 9. The cluster size distribution of pad-MRPC.
Fig. 6. An example of velocity correction curve, the Gaussian mean ΔT as a function of ΔTdia . The curve is a piecewise function fit to the data points.
To reduce the impact from clustering and investigate the timing ability difference between the two tested detectors, a single-hit event study was done. A single-hit event for pad-MRPC/BucRef means there is only one pad/strip fired in this event. The single-hit events for pad-MRPC/BucRef were selected and the calibration procedure was done to a single pad and strip again. Fig. 10 shows the result of single-hit events study. The up left plot is for all events, the ΔT distribution goes wider since not the fastest tdcs but the tdcs of a specific pad/strip are selected. The up right plot shows the single-hit event for pad, the timing resolution does not change much. The down left plot is for single-hit event for BucRef and the timing resolution improves a lot. The down right plot is for single-hit event for both pad-MRPC and strip, the timing
Please cite this article as: Y. Wang, et al., Nuclear Instruments & Methods in Physics Research A (2016), http://dx.doi.org/10.1016/j. nima.2016.06.133i
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Fig. 10. The ΔT distribution of different events in single-hit events study. The up left plot is for all events, the up right plot shows the single-hit event for pad, the down left plot is for single-hit event for BucRef and the down right plot is for single-hit event for both pad-MRPC and BucRef.
resolution is 87/ 2 = 62 ps for single detector. This study implies that the BucRef suffers more form clusters and pad-MRPC may have a better timing resolution for all events.
of China (11420101004, 11461141011, 11275108) and supported by the Ministry of Science and Technology under Grant no. 2015CB856905. We also thank the CBM Collaboration for their support.
4. Conclusion Real size MRPC prototypes have been developed for CBM-TOF inner region. The prototypes assembled with low resistive glass have 10 0.22 mm gas gaps. The active area of the prototypes is 176 mm 42 mm, which is sub-divided into sixteen 20 mm 20 mm readout pads with an 2 mm interval between pads. A timing resolution around 60 ps and an efficiency of over 98% were obtained in a cosmic test and a beam test at GSI. The results show that the real-size prototypes fulfill the requirements of the CBM-TOF.
References [1] Technical Design Report for the CBM Time-of-Flight System: 〈http://repository. gsi.de/record/109024/files/tof-tdr-final_rev6036.pdf〉. [2] I. Deppner, et al., J. Instrum. 7 (10) (2012) C10014. [3] I. Deppner, et al., Nucl. Instrum. Methods Phys. Res. Sect. A 661 (2012) 121. [4] A.N. Akindinov, et al., Nucl. Instrum. Methods Phys. Res. Sect. A 533 (2004) 74. [5] E.C. Zeballos, et al., Nucl. Instrum. Methods Phys. Res. Sect. A 374 (1996) 132. [6] Y. Wang, et al., J. Instrum. 9 (8) (2014) C08003. [7] J.B. Wang, et al., Nucl. Instrum. Methods Phys. Res. Sect. A 713 (2013) 40. [8] W.P. Zhu, et al., Nucl. Instrum. Methods Phys. Res. Sect. A 56.11 (2013) 2821. [9] J. Wang, et al., Online aging study of high rate MRPC: arXiv:1508.03394. [10] M. Ciobanu, et al., Proc. IEEE (2009) 401.
Acknowledgments This work is supported by National Natural Science Foundation
Please cite this article as: Y. Wang, et al., Nuclear Instruments & Methods in Physics Research A (2016), http://dx.doi.org/10.1016/j. nima.2016.06.133i