Sheng Lizhi

A Single Photon Counting Detector Based on One-Dimensional Vernier Anode

The mathematical expression on decoding the one-dimensional (1D) Vernier anode is deduced theoretically, and the corresponding 1D-Vernier anode collector is developed. A photon counting imaging and detection system is constructed based on a 1D-Vernier anode detector and electronic readout subsystem. With wavelengths of 253.7 nm from the mercury lamp as the ultraviolet emission source, the spatial resolution of the prototype is proved to be better than 100μm along the x-direction in experiment.

Imaging properties of a tetra wedge readout

The decoding principle of a tetra wedge anode, which is a development of the wedge and strip anode, is described. The influence of charge cloud size on decoding accuracy is studied using the Monte Carlo method. Simulation results show that the decoding error is large when the size of charge clouds collected by the anode is small. Thus, the charge clouds collected by the tetra wedge anode should reach a necessary size to ensure accurate decoding. Finally, using the ultraviolet photon counting imaging system, the linearity and the spatial resolution of the system are tested. Experimental results show that the system has a good linearity and the spatial resolution is better than 100 μm.

Fluorescence X-ray source used for calibrating the detector of X-ray navigation

Lots of research work on the X-ray pulsar navigation detector has been carried out, but the rigorous quantitative calibration results of these detectors have never been given out. In order to further promote the research process in X-ray pulsar navigation field, a kind of high-precision X-ray source which could be tunable in energy distribution and photon flux is necessary. A new method has been proposed to generate such an X-ray source, in which a conventional X-ray tube which is called the original level tube is used to excite a special fluorescence target to generate fluorescence X-ray source. Firstly, the primary experiment system is built, with which the intensity of the fluorescence X-ray source is measured in atmospheric environment. The result indicates that the fluorescence X-ray source can be implemented in vacuum system to calibrate the detectors. Then an integral fluorescence X-ray source is fabricated which can be used in vacuum system and its intensity is measured under the condition of D-x = 300 cm and I-a = 200 mu A. The photo fluxes are obtained to be 19.57 phs/s at 4.51 keV, 25.22 phs/s at 5.41 keV, and 33.27 phs/s at 8.05 keV. These data demonstrate the correctness of our method and that this new fluorescence X-ray source can be used to calibrate the x-ray pulsar navigation detector.

A space audio cummunication system based on X-ray

In this paper, an X-ray communication program, which consists of a sender of grid controlled X-ray source and a receiver of X-ray single-photon detector based on micro-channel plate, is presented. With the detailed information about the signal modulation transmitter, the micro-channel-based X-ray single-photon detector as well as the signal receiving demodulator, a space audio communication system based on X-ray is built. The communication rate of more than 20 kbit/s is realized. According to the preliminary test result analyses of the X-ray space audio communication system test, the X-ray emission success rate restricts the communication speed by the influence of different X-ray intensities, signal shaping time and threshold settings respectively. Therefore, a scheme for further increasing X-ray communication performance is suggested.

Two-dimensional photon counting imaging detector based on a Vernier position sensitive anode readout

A two-dimensional photon counting imaging detector based on a vernier position sensitive anode is reported. the decode principle and design of a two-dimensional vernier anode are introduced in detail. a photon counting imaging system was built based on a vernier anode. the image of very weak optical radiation can be reconstructed by image processing in a period of integration time. the resolution is superior to 100 mu m according to the resolution test. the detector may realize the imaging of very weak particle flow of high-energy photons, electrons and ions, so it can be used for high-energy physics, deep space exploration, spectral measurement and bio-luminescence detection.