A test system is developed for the BESIII ETOF/MRPC beam tests of data acquisition, environment monitoring and automatic control. The software framework is based on the CAMAC bus, VME bus and Serial Port,which are res...A test system is developed for the BESIII ETOF/MRPC beam tests of data acquisition, environment monitoring and automatic control. The software framework is based on the CAMAC bus, VME bus and Serial Port,which are responsible for communications with the detectors. The monitor system works well in the beam test.展开更多
The endcap of time-of-flight （ETOF） detector in BES （Beijing Spectrometer） III is planned to be upgraded by using multi-gap resistive plate chambers （MRPCs） and the designed time resolution of the MRPCs is aroun...The endcap of time-of-flight （ETOF） detector in BES （Beijing Spectrometer） III is planned to be upgraded by using multi-gap resistive plate chambers （MRPCs） and the designed time resolution of the MRPCs is around 50 ps. Thus a time-zero （TO） detector needs to be built to offer a high quality reference time for the MRPCs beam test. So a TO detector is built using plastic scintillator tiles （BC420） to couple with four fast phototubes （PMTs, Hamamatsu H6533）. The timing properties of the detector is studied by using a cosmic ray test and factors related to the time resolution, such as plastic scintillator size, readout mode and angle effects, are discussed. TO detector timing resolutions of -41-62 ps are achieved, which means that the TO detector can be used in the MRPC beam test.展开更多
LiYSiO4：Ce is a promising scintillator and some of its properties have been reported in previous papers. In this paper, samples doped with different concentrations of Ce are prepared and studied. First, the relative ...LiYSiO4：Ce is a promising scintillator and some of its properties have been reported in previous papers. In this paper, samples doped with different concentrations of Ce are prepared and studied. First, the relative light yields of the samples are measured as 28.1%-37.1% compared with a standard anthracene crystal being irradiated by a particles and as -27.270 compared with NaI being irradiated by X-rays. Second, the effects of sample thicknesses on light yields are presented. Finally the timing behaviors of samples with different doped concentrations being irradiated with alpha particles and X-rays are discussed. The result shows that LiYSiOa：Ce is a kind of fast scintillator （- 30 ns） with a moderate light yield that can be used for neutron detection.展开更多
We report an improved measurement of the neutrino mixing angle θ13 from the Daya Bay Reactor Neutrino Experiment. We exclude a zero value for sin22θ13 with a significance of 7.7 standard deviations. Electron antineu...We report an improved measurement of the neutrino mixing angle θ13 from the Daya Bay Reactor Neutrino Experiment. We exclude a zero value for sin22θ13 with a significance of 7.7 standard deviations. Electron antineutrinos from six reactors of 2.9 GWm th were detected in six antineutrino detectors deployed in two near （flux-weighted baselines of 470 m and 576 m） and one far （1648 m） underground experimental halls. Using 139 days of data, 28909 （205308） electron antineutrino candidates were detected at the far hall （near halls）. The ratio of the observed to the expected number of antineutrinos assuming no oscillations at the far hall is 0.944± 0.007（stat.） ± 0.003（syst.）. An analysis of the relative rates in six detectors finds sin22θ13=0.089± 0.010（stat.）±0.005（syst.） in a three-neutrino framework.展开更多
A position-sensitive detector is designed for neutron detection. It uses a single continuous screen of a self-made lithium glass scintillator, rather than discrete crystal implementations, coupling with a multi-anode ...A position-sensitive detector is designed for neutron detection. It uses a single continuous screen of a self-made lithium glass scintillator, rather than discrete crystal implementations, coupling with a multi-anode PMT （MaPMT）. The scintillator is fast and efficient; with a decay time of 34 ns and thermal neutron detection efficiency of around 95.8% for the 3 mm thick screen, and its light yield is around 5670 photons per neutron and 3768 photons per MeV γ rays deposition. The spatial resolution is around 1.6 mm （FWHM） with the energy resolution around 34.7% by using α （5.2 MeV） rays test.展开更多
In order to study the possibility of improving the timing performance of the time of flight （TOF） systems, which are made of plastic scintillator counters, and read out by photomultiplier tubes （PMT） with mesh dyn...In order to study the possibility of improving the timing performance of the time of flight （TOF） systems, which are made of plastic scintillator counters, and read out by photomultiplier tubes （PMT） with mesh dynodes and conventional electronics, we have conducted a study using faster PMTs and ultra fast waveform digitizers to read out the plastic scintillators. Different waveform analysis methods are used to calculate the time resolution of such a system. Results are compared with the conventional discriminating method based on a threshold and pulse height. Our tests and analysis show that significant timing performance improvements can be achieved by using this new system.展开更多
A prototype multi-gap resistive plate chamber （MRPC） with a 2 × 6 gap structure is developed for the upgrading of the endcap time-of-flight （ETOF） detector in the Beijing Spectrometer （BESⅢ ）. The prototyp...A prototype multi-gap resistive plate chamber （MRPC） with a 2 × 6 gap structure is developed for the upgrading of the endcap time-of-flight （ETOF） detector in the Beijing Spectrometer （BESⅢ ）. The prototype MRPC is tested in the E3 beam line of the Beijing Electron Positron Collider （BEPC） with secondary charged particles （π and p, etc） of 600 MeV/c. The test results show that the time resolution of the MRPC can reach 50 ps and that the detection efficiency is greater than 98%.展开更多
基金Supported by the State Key program of National Natural Science of China(No.10979003)National Natural Science Foundation of China(No.10775181)China Postdoctoral Science Foundation(No.20090460521)
文摘A test system is developed for the BESIII ETOF/MRPC beam tests of data acquisition, environment monitoring and automatic control. The software framework is based on the CAMAC bus, VME bus and Serial Port,which are responsible for communications with the detectors. The monitor system works well in the beam test.
基金Supported by State Key program of National Natural Science of China (10979003,10775181,10875140)China PostdoctoralScience Foundation (20090460521)
文摘The endcap of time-of-flight （ETOF） detector in BES （Beijing Spectrometer） III is planned to be upgraded by using multi-gap resistive plate chambers （MRPCs） and the designed time resolution of the MRPCs is around 50 ps. Thus a time-zero （TO） detector needs to be built to offer a high quality reference time for the MRPCs beam test. So a TO detector is built using plastic scintillator tiles （BC420） to couple with four fast phototubes （PMTs, Hamamatsu H6533）. The timing properties of the detector is studied by using a cosmic ray test and factors related to the time resolution, such as plastic scintillator size, readout mode and angle effects, are discussed. TO detector timing resolutions of -41-62 ps are achieved, which means that the TO detector can be used in the MRPC beam test.
基金Supported by National Natural Science Foundation of China(10875140)
文摘LiYSiO4：Ce is a promising scintillator and some of its properties have been reported in previous papers. In this paper, samples doped with different concentrations of Ce are prepared and studied. First, the relative light yields of the samples are measured as 28.1%-37.1% compared with a standard anthracene crystal being irradiated by a particles and as -27.270 compared with NaI being irradiated by X-rays. Second, the effects of sample thicknesses on light yields are presented. Finally the timing behaviors of samples with different doped concentrations being irradiated with alpha particles and X-rays are discussed. The result shows that LiYSiOa：Ce is a kind of fast scintillator （- 30 ns） with a moderate light yield that can be used for neutron detection.
基金Supported by the Ministry of Science and Technology of Chinathe United States Department of Energy+15 种基金the Chinese Academy of Sciencesthe National Natural Science Foundation of Chinathe Guangdong provincial governmentthe Shenzhen municipal governmentthe China Guangdong Nuclear Power GroupShanghai Laboratory for Particle Physics and Cosmologythe Research Grants Council of the Hong Kong Special Administrative Region of ChinaUniversity Development Fund of The University of Hong Kongthe MOE program for Research of Excellence at NTU, NCTUNSC fund support from Taipeithe U.S. National Science Foundationthe Alfred P. Sloan Foundationthe Ministry of EducationYouth and Sports of the Czech Republicthe Czech Science Foundationthe Joint Institute of Nuclear Research in Dubna,Russia
文摘We report an improved measurement of the neutrino mixing angle θ13 from the Daya Bay Reactor Neutrino Experiment. We exclude a zero value for sin22θ13 with a significance of 7.7 standard deviations. Electron antineutrinos from six reactors of 2.9 GWm th were detected in six antineutrino detectors deployed in two near （flux-weighted baselines of 470 m and 576 m） and one far （1648 m） underground experimental halls. Using 139 days of data, 28909 （205308） electron antineutrino candidates were detected at the far hall （near halls）. The ratio of the observed to the expected number of antineutrinos assuming no oscillations at the far hall is 0.944± 0.007（stat.） ± 0.003（syst.）. An analysis of the relative rates in six detectors finds sin22θ13=0.089± 0.010（stat.）±0.005（syst.） in a three-neutrino framework.
基金Supported by the National Natural Science Foundation of China(10875140,10890092)
文摘A position-sensitive detector is designed for neutron detection. It uses a single continuous screen of a self-made lithium glass scintillator, rather than discrete crystal implementations, coupling with a multi-anode PMT （MaPMT）. The scintillator is fast and efficient; with a decay time of 34 ns and thermal neutron detection efficiency of around 95.8% for the 3 mm thick screen, and its light yield is around 5670 photons per neutron and 3768 photons per MeV γ rays deposition. The spatial resolution is around 1.6 mm （FWHM） with the energy resolution around 34.7% by using α （5.2 MeV） rays test.
基金Supported by National Natural Science Foundation of China(10979003)Main Direction Program of Knowledge Innovation Project of Chinese Academy of Sciences
文摘In order to study the possibility of improving the timing performance of the time of flight （TOF） systems, which are made of plastic scintillator counters, and read out by photomultiplier tubes （PMT） with mesh dynodes and conventional electronics, we have conducted a study using faster PMTs and ultra fast waveform digitizers to read out the plastic scintillators. Different waveform analysis methods are used to calculate the time resolution of such a system. Results are compared with the conventional discriminating method based on a threshold and pulse height. Our tests and analysis show that significant timing performance improvements can be achieved by using this new system.
基金Supported by National Natural Science Foundation of China (10979003, 10875120)Major State Basic Research Development Program (2008CB817702)
文摘A prototype multi-gap resistive plate chamber （MRPC） with a 2 × 6 gap structure is developed for the upgrading of the endcap time-of-flight （ETOF） detector in the Beijing Spectrometer （BESⅢ ）. The prototype MRPC is tested in the E3 beam line of the Beijing Electron Positron Collider （BEPC） with secondary charged particles （π and p, etc） of 600 MeV/c. The test results show that the time resolution of the MRPC can reach 50 ps and that the detection efficiency is greater than 98%.
