J. W. Zhang

Calibration algorithms of RPC detectors at Daya Bay Neutrino Experiment

During the commissioning of RPC detector systems at the Daya Bay Reactor Neutrino Experiment, calibration algorithms were developed and tuned, in order to evaluate and optimize the performance of the RPC detectors. Based on a description of the hardware structure of the RPC detector systems, this paper introduces the algorithms used for detector calibration, including trigger rate, efficiency, noise rate, purity and muon flux.

Spatial resolution measurement of triple-GEM detector and diffraction imaging test at synchrotron radiation

A triple-GEM detector with two-dimensional readout is developed. The detector provides high position resolution for powder diffraction experiments at synchrotron radiation. Spatial resolution of the detector is measured in the lab using a 55Fe X-ray source. A resolution of about 110 μm FWHM is achieved. The energy resolution is better than 27% for 5.9 keV X-rays. The detectors validity under illumination of photons in particular energy range is verified using a Cu X-ray tube. Imaging of the head of a wire stripper with X-ray tube demonstrates its imaging ability. A diffraction imaging experiment using the sample of powder SiO2 is successfully carried out at 1W2B laboratory of Beijing Synchrotron Radiation Facility (BSRF). Different diffraction rings are clearly seen under various X-ray energies.

HEPS-BPIX, a hybrid pixel detector system for the High Energy Photon Source in China

A hybrid pixel detector with single photon counting mode has been designed for the High Energy Photon Source in China. It features a pixel size of 150 μm × 150 μm and a frame rate up to 1.2 kHz with 20-bit dynamic range. Six modules were assembled as the first prototype system, covering an area of 9 cm × 10 cm with 360k pixels. Images have been taken using X-ray and synchrotron radiation light, and the preliminary detector performance is presented.

Developments of oil-free Bakelite resistive plate chambers for particle physics experiments

In this paper, we sumarized a Bakelite Resistive Plate Chamber (RPC) with non-oil surface treatment. This type of RPC has been installed and run smoothly in BESIII Muon identification system and Daya Bay cosmic Muon veto system. Based on its good performances, it has been futher studied as the sensitive detector of a digital hadron calorimeter for measuring the energies of particles in a hadron jet and as a thermal neutron detector. In addition, since the bulk resistivity of Bakelite plates can be controlled, futher developments with low bulk resistivity are being undertaken to guarantee high rate capability in experiments.

The study and design of the large area neutron monitor with RPC-Gd

Thermal neutron absorber gadolinium (Gd) with a large reaction cross section is applied to resistive plate chamber detectors, so a gaseous detector RPC-Gd is developed to discriminate thermal neutrons. Through analyzing the operation principle of RPC-Gd detectors and testing n/gamma spectrum, a method by supplying different operation high voltage of RPC module is used for discriminating thermal neutrons and gamma. In the end, based on the production technology and operation principle of RPC, two prototypes of single/double RPC modules are designed for producing large area and low cost detector to monitor thermal neutron.

The properties of glass resistive plate chambers made of different glasses

Glass resistive plate chambers (GRPCs) have been proposed as the basic element for the JUNO top tracker detector. With good uniform performance and low cost, GRPCs are well suited for large area experiments. Glass RPCs used in underground experiments require specially designed cassette and gas flow systems, since the glass is fragile and easily corroded by acid generated by water entering the gas-filled chamber. High-strength and chemical-resistant glasses have been proposed for underground experiments. We present here the test results of four GRPC chambers made of different glasses: normal thin glass, two high-strength glasses, and a chemical-resistant glass. The chemical-resistant and high-strength glasses have good surface quality, but their volume resistivities are higher. Higher resistivities lead to a higher required voltage to reach plateau operation, meaning that these glasses can only work in a very low rate experiment.