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1. chinaXiv:201609.01042 [pdf]

The cosmic ray test of MRPCs for the BESIII ETOF upgrade

Wang Xiao-Zhuang; Heng Yue-Kun; Wu Zhi; Li Cheng; Sun Yong-Jie; Dai Hong-Liang; Sun Sheng-Sen; Yang Rong-Xing; Cao Ping; Zhang Jie; Wang Yun; Sun Wei-Jia; Wang Si-Yu; Ji Xiao-Lu; Zhao Jin-Zhou; Gong Wen-Xuan; Ye Mei; Ma Xiao-Yan; Chen Ming-Ming; Xu Mei-hang
Subjects: Physics >> Nuclear Physics

In order to improve the particle identification capability of the Beijing Spectrometer III (BESIII),t is proposed to upgrade the current endcap time-of-flight (ETOF) detector with multi-gap resistive plate chamber (MRPC) technology. Aiming at extending ETOF overall time resolution better than 100ps, the whole system including MRPC detectors, new-designed Front End Electronics (FEE), CLOCK module, fast control boards and time to digital modules (TDIG), was built up and operated online 3 months under the cosmic ray. The main purposes of cosmic ray test are checking the detectors' construction quality, testing the joint operation of all instruments and guaranteeing the performance of the system. The results imply MRPC time resolution better than 100ps, efficiency is about 98%燼nd the noise rate of strip is lower than 1Hz/(scm2) at normal threshold range, the details are discussed and analyzed specifically in this paper. The test indicates that the whole ETOF system would work well and satisfy the requirements of upgrade.

submitted time 2016-09-14 Hits2116Downloads1370 Comment 0

2. chinaXiv:201609.01023 [pdf]

Study of the Tracking Method and Expected Performance of the Silicon Pixel Inner Tracker Applied in BESIII

Qinglei Xiu; Mingyi Dong; Weidong Li; Huaimin Liu; Qiumei Ma; Qun Ouyang; Zhonghua Qin; Liangliang Wang; Linghui Wu; Ye Yuan; Yao Zhang
Subjects: Physics >> Nuclear Physics

The inner drift chamber of the BESIII is encountering serious aging problem after five year's running. For the first layer, the decrease in gas gain is about 26% from 2009 to 2013. The upgrade of the inner tracking detector has become an urgent problem for the BESIII experiment. An inner tracker using CMOS pixel sensors is an important candidate because of its great advantages on spatial resolution and radiation hardness. In order to carry out a Monte Carlo study on the expected performance, a Geant4-based full simulation for the silicon pixel detector has been implemented. The tracking method combining the silicon pixel inner tracker and outer drift chamber has been studied and a preliminary reconstruction software was developed. The Monte Carlo study shows that the performances including momentum resolution, vertex resolution and the tracking efficiency are significantly improved due to the good spatial resolution and moderate material budget of the silicon pixel detector.

submitted time 2016-09-14 Hits1459Downloads825 Comment 0

3. chinaXiv:201609.00946 [pdf]

Preliminary study of light yield dependence on LAB liquid scintillator composition

YE Xing-Chen; YU Bo-Xiang; ZHOU Xiang; ZHAO Li; DING Ya-Yun; LIU Meng-Chao; DING Xue-Feng; ZHANG Xuan; JIE Quan-Lin; ZHOU Li; FANG Jian; CHEN Hai-Tao; HU Wei; NIU Shun-Li; YAN Jia-Qing; ZHAO Hang; HONG Dao-Jin
Subjects: Physics >> Nuclear Physics

Liquid scintillator (LS) will be adopted as the detector material in JUNO (Jiangmen Underground Neutrino Observatory). The energy resolution requirement of JUNO is 3%, which has never previously been reached. To achieve this energy resolution, the light yield of liquid scintillator is an important factor. PPO (the fluor) and bis-MSB (the wavelength shifter) are the two main materials dissolved in LAB. To study the influence of these two materials on the transmission of scintillation photons in LS, 25 and 12 cm-long quartz vessels were used in a light yield experiment. LS samples with different concentration of PPO and bis-MSB were tested. At these lengths, the light yield growth is not obvious when the concentration of PPO is higher than 4 g/L. The influence from bis-MSB becomes insignificant when its concentration is higher than 8 mg/L. This result could provide some useful suggestions for the JUNO LS.

submitted time 2016-09-13 Hits1610Downloads891 Comment 0

4. chinaXiv:201609.00925 [pdf]

Study of the Beamstrahlung Effects at the CEPC

Xiu Qinglei; Zhu Hongbo; Lou Xinchou
Subjects: Physics >> Nuclear Physics

The discovery of a 125 GeV Higgs boson at the LHC marked a breakthrough in particle physics. The relative lightness of the new particle inspires the consideration of a high luminosity Circular Electron Positron Collider (CEPC) as a Higgs Factory to study the Higgs boson in a clean environment. At the CEPC, the beamstrahlung might represent one of the most important sources of beam-induced backgrounds that will impact the detector. It will introduce additional backgrounds to the CEPC detector through the subsequent electron-positron pair production and the hadronic process. Therefore its impacts should be carefully evaluated. In this paper, the beamstrahlung-induced backgrounds are first estimated with analytical methods and are further evaluated in detail with Monte Carlo simulation. The detector occupancy due to the beamstrahlung at the location where the first vertex detector layer may be placed is found to be well below 0.5%. Radiation levels characterised as non-ionising energy loss (NIEL) and total ionising dose (TID) are estimated to be ~?0111燤eV爊eq/cm2/yr and ~ 300 kRad/yr, respectively.

submitted time 2016-09-13 Hits1326Downloads693 Comment 0

5. chinaXiv:201609.00914 [pdf]

Aging effect in the BESIII drift chamber

DONG Ming-Yi; XIU Qing-Lei; WU Ling-Hui; WU Zhi; QIN Zhong-Hua; SHEN Pin; AN Fen-Fen; JU Xu-Dong; LIU Yi; ZHU Kai; OU-YANG Qun; CHEN Yuan-Bo
Subjects: Physics >> Nuclear Physics

As the main tracking detector of BESIII, the drift chamber works for accurate measurements of the tracking and the momentum of the charged particles decayed from the reaction of BEPCII e+ and e-. After operation six years, the drift chamber is suffering from aging problems due to huge beam related background. The gains of the cells in the first ten layers experience an obvious decrease, reaching a maximum of about 29% for the first layer cells. Two calculation methods for the gains change (Bhabha events and accumulated charges with 0.3% aging ratio for inner chamber cells) get almost the same results. For the Malter effect encountered by the inner drift chamber in Jan., 2012, about 0.2% water vapor was added to MDC gas mixture to solve this cathode aging problem. These results provide an important reference for MDC operation high voltage setting and the upgrade of the inner drift chamber.

submitted time 2016-09-13 Hits1677Downloads966 Comment 0

6. chinaXiv:201609.00908 [pdf]

Evaluation of new large area PMT with high quantum efficiency

LEI Xiang-Cui; HENG Yue-Kun; QIAN Sen; XIA Jing-Kai; LIU Shu-Lin; WU Zhi; YAN Bao-Jun; XU Mei-Hang; WANG Zheng LI Xiao-Nan; RUAN Xiang-Dong; Wang Xiao-Zhuang; YANG Yu-Zhen; WANG Wen-Wen; FANG Can; LUO Feng-Jiao; LIANG Jing-Jing 1,4 YANG Lu-Ping 1,7 YANG Biao 1,2
Subjects: Physics >> Nuclear Physics

The neutrino detector of the Jiangmen Underground Neutrino Observatory (JUNO) is designed to use 20 kilotons of liquid scintillator and approximately 16,000 20-inch photomultipliers (PMTs).One of the options is to use the 20-inch R12860 PMT with high quantum efficiency which has recently been developed by Hamamatsu Photonics. The performance of the newly developed PMT preproduction samples is evaluated. The results show that its quantum efficiency is?0%燼t?00nm. Its Peak/Valley (P/V) ratio for the single photoelectron is 4.75 and the dark count rate is?7kHz燼t the threshold of 3 mV while the gain is at??07. The transit time spread of a single photoelectron is2.86ns. Generally the performances of this new 20-inch PMT are improved over the old one of R3600.

submitted time 2016-09-13 Hits1562Downloads936 Comment 0

7. chinaXiv:201609.00888 [pdf]

The study of the aging behavior on large area MCP-PMT

WANG Wen-Wen; QIAN Sen; QI Minga XIA Jing-Kai; CHENG Ya-Ping; NING Zhe; LUO Feng-Jiao; HENG Yue-Kun; LIU Shu-Lin; SI Shu-Guang; Sun Jian-Ning; LI Dong; WANG Xing-Chao; HUANG Guo-Rui; TIAN Jing-Shou; WEI Yong-Lin; LIU Hu-Lin; LI Wei-Hua; WANG Xing; XIN Li-Wei
Subjects: Physics >> Nuclear Physics

Aging experiments of a novel type of large area MCP-PMT made by JUNO collaboration were conducted.In these aging experiments, the multi-photoelectron spectrum and single photoelectron spectrum were measured daily,as well as the MCP resistance of the second PMT before and after the experiment. Two PMTs were aged successivelyfor cross check. The first PMT was aged for 52 days, while the other one was aged for 84 days. In order to study the mechanism of the aging process, the high voltage on the second PMT was increased to accelerate its aging process when the cumulative output of charge from its anode was about 4 C. From our study, it can be known that large area MCP-PMT aging had a strong relationship with the related MCPs. In accordance with the PMT aging curve,a PMT aging model was setup and a general aging formula was given.

submitted time 2016-09-13 Hits1596Downloads933 Comment 0

8. chinaXiv:201609.00885 [pdf]

Test of a fine pitch SOI pixel detector with laser beam

LIU Yi; LU Yunpeng; JU Xudong; OUYANG Qun
Subjects: Physics >> Nuclear Physics

A silicon pixel detector with fine pitch size of 19x19 um, developed base on SOI (silicon on insulator) technology, was tested under the illumination of infrared laser pulses. As an alternative way to particle beam tests, the laser pulses were tuned to very short duration and small transverse profile to simulate the tracks of MIPs (minimum ionization particles) in silicon. Hit cluster sizes were measured with focused laser pulses propagating through the SOI detector perpendicular to its surface and most of the induced charge was found to be collected inside the seed pixel. For the first time, the signal amplitude as a function of the applied bias voltage was measured for this SOI detector, deepening understanding of its depletion characteristics.

submitted time 2016-09-13 Hits1394Downloads756 Comment 0

9. chinaXiv:201609.00002 [pdf]

The test of the electronics system for the BESIII ETOF upgrade

WANG Xiao-Zhuang; DAI Hong-Liang; WU Zhi; HENG Yue-Kun; Zhang Jie; CAO Ping; JI Xiao-Lu; Li Cheng; SUN Wei-Jia; WANG Si-Yu; WANG Yun
Subjects: Physics >> Nuclear Physics

It is proposed to upgrade the endcap time-of-flight (ETOF) of the Beijing Spectrometer III (BESIII) with multi-gap resistive plate chamber (MRPC), aiming at overall time resolution about 80 ps. After the entire electronics system is ready, some experiments, such as heat radiating, irradiation hardness and large-current beam tests,are carried out to certify the electronics' reliability and stability. The on-detector test of the electronics is also performed with the beam at BEPCII E3 line, the test results indicate that the electronics system fulfills its design requirements.

submitted time 2016-09-01 Hits2178Downloads1131 Comment 0

10. chinaXiv:201608.00212 [pdf]

Design and optimization of resistive anode for a two-dimensional imaging triple-GEM detector

JU Xu-Dong; DONG Ming-Yi; ZHAO Yi-Chen; ZHOU Chuan-Xing; OUYANG Qun
Subjects: Physics >> Nuclear Physics

The optimization of resistive anode for two dimensional imaging detectors which consists of a series of high resistive square pads surrounding by low resistive strips has been studied by both numerical simulations and experimental tests. It has been found that to obtain good detector performance, the resistance ratio of the pad to the strip should be larger than 5, the nonuniformity of the pad surface resistivity had better be less than?20%, a smaller pad width leads to a smaller spatial resolution and when the pad width is?6mm, the spatial resolution (σ) can reach about?105μm. Based on the study results, a 2-D GEM detector prototype with the optimized resistive anode is constructed and a good imaging performance is achieved.

submitted time 2016-08-31 Hits1580Downloads838 Comment 0

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