Sun Yong-Jie

A prototype MRPC beam test for the BESIII ETOF upgrade

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%.

Time calibration for the end cap TOF system of BESIII

The time calibration for end cap TOF system of BESIII is studied in this paper. It has achieved about 110 ps time resolution for muons in dimu events. The pulse height correction using electronic scan curve and the predicted time calculated using Kalman filter method are introduced. This paper also describes the study of using electrons and muons as calibration samples.

A large-area GEM detector using a novel self-stretching technique

A Gas Electron Multiplier (GEM) detector with an effective area of 300 mm×300 mm has been constructed using a novel self-stretching technique, which allows a highly flexible and efficient GEM detector assembly free of glue or spacers. This makes the re-opening and repair of the GEM detectors possible and significantly reduces the scrap rate in the mass production of large-area GEM detectors. With the technique, the assembly time can be limited to a few hours, a factor of ten improvement compared to that using gluing techniques. The details of design and assembly procedure of the 300 mm×300 mm GEM detector are described in this paper. This detector was tested with 8 keV X-rays for the effective gain, energy resolution and performance uniformity. The results show that the typical energy resolution is 20% at an effective gain of about 104, with fairly good uniformity.

An X-ray imaging device based on a GEM detector with delay-line readout

An X-ray imaging device based on a triple-GEM (Gas Electron Multiplier) detector, a fast delay-line circuit with 700 MHz cut-off frequency and two dimensional readout strips with 150 μm width on the top and 250 μm width on the bottom, is designed and tested. The localization information is derived from the propagation time of the induced signals on the readout strips. This device has a good spatial resolution of 150 μm and works stably at an intensity of 105 Hz/mm2 with 8 keV X-rays.

A cosmic ray test platform based on high time resolution MRPC technology

In order to test the performance of detector prototypes in a laboratory environment, we design and build a large area (90 cm×52 cm) test platform for cosmic rays based on a well-designed Multi-gap Resistive Plate Chamber (MRPC) with excellent time resolution and a high detection efficiency for minimum ionizing particles. The time resolution of the MRPC module used is tested to be ~80 ps, and the position resolution along the strip is ~5 mm, while the position resolution perpendicular to the strip is ~12.7 mm. The platform constructed by four MRPC modules can be used for tracking cosmic rays with a spatial resolution of ~6.3 mm, and provide a reference time ~40 ps.

Design of the photomultiplier tube bases for high dynamic range readout in WCDA

The photomultiplier tube (PMT) used in the water Cherenkov detector array (WCDA) of the Large High Altitude Air Shower Observatory (LHAASO) requires a good single photoelectron (SPE) spectrum and a charge dynamic range from 1 to 4000 photoelectrons. In this paper, the bases design and improvement of the photomultiplier tube R5912 are presented. The results show that at the gain of 2.6 × 106, the anode output has a good single photoelectron spectrum, and its charge non-linearity is within 5% when the number of photoelectrons (nPE) is 3500. The charge non-linearity of the 8th dynode output is within 2% when the number of nPE is 4000, which satisfies the dynamic range requirement.

New type gaseous detector-MRPC

We review the development of a new type gaseous detector, MRPC (Multi-gap Resistive Plate Chamber, MRPC) in the last decade in China. With the successful operation in the STAR experiment at RHIC (Relativistic Heavy Ion Collider, RHIC) and the outstanding importance in charged particle identification, the MRPC technology has gained extensive interest and progress in the high-energy nuclear and particle physics.

Cosmic ray test for a T0 detector

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 (T0) detector needs to be built to offer a high quality reference time for the MRPCs beam test. So a T0 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. T0 detector timing resolutions of ~41–62 ps are achieved, which means that the T0 detector can be used in the MRPC beam test.

Beam test of signal cross-talk and transmission for LMPRC

A new prototype of large area Multi-gap Resistive Plate Chamber (MRPC) with long readout strips was built. This Long-strip Multi-gap Resistive Plate Chamber (LMRPC) is double stacked and has ten 250 μm-thick gas gaps. Signals are read out from the two ends of each strip with an active area of 50 cm × 2.5 cm in each. The detector was tested at FOPI in GSI, using the secondary particles of proton beams (E = 3.5 GeV) colliding with a Pb target. The results show that the LMRPC prototype has a time resolution of about 60–70 ps; the detecting efficiency is over 98% and the ratio of cross-talk is lower than 2%. The detector also has a good spatial resolution of 0.36 cm along the strip direction.

BESIII barrel time-of-flight （TOF） calibration using cosmic ray data

The principle of the method for the BESⅢ TOF calibration using cosmic ray data without magnetic field are reported in this paper. After applying calibration constants, the single-end readout time resolution could reach about 150 ps, and the time resolution for one layer is achieved to be about 110 p...