Search

As a two dimensional arrays of micro-channel X-ray imaging precision optics, detection efficiency and imaging quality are crucial to micro-channel optics (MPO). As a key factor of the detection efficiency and imaging quality, cell packed geometries in the Wolter type micro-channel optics were investigated in the paper. The characteristics of simulative images for different cell packed geometries were compared with the software Tracepro by ray trace method of Monte Carlo algorithm. The influences for the amount of symmetry axes, chamber types and stacked density of layers on the focal imaging characteristics and detection efficiency of Wolter type micro-channel optics were explored. The results indicated that the detection efficiency and the quality of focal imaging changing both obeyed Parabola distribution with the increasing of the numbers of symmetry axis from three to six. In the cambered stacking models, focusing images showed a petaline shape dispersion background with the same symmetry axis in non-full-cambered stacking types. In the close-packed loss model, it had a minimal and maximal impact on the detection efficiency in the outmost layer and subouter layer, respectively. Besides, characteristics of simulative images for Lobster eye micro-channel optics (L-MPO) and Wolter type micro-channel optics (W-MPO) were compared by ray trace method in this paper. Results indicated that under a constant illumination with the same cell size, the simulated detection efficiency of ideal W-MPO was over 41.0%, which was 1.3 times than that of ideal L-MPO.

With the development of electronic displays becoming flat and portable, field emission displays (FED) get the widespread attention because they have the advantages of flat-panel displays and CRT displays together. At present, as one of the core components in FED, the screen is still the short board in the application of FED. With thin film phosphor as the phosphor layer, the screen will be very beneficial to the application of FED because of many advantages of extremely high resolution, strong adhesion, good smoothness, low release of gas, good conductivity and so on. That highlights the important application value and research significance of thin film phosphor in FED. In this review, we summarize the recent advances in the thin film phosphors for FED with emphasis on the film materials, preparation technology, and the main problems in the film. And the further study of thin film phosphors in FED is also presented.

Micro-channel plate (MCP) is a two dimensional arrays of microscopic channel charge particle multiplier. Silicate composition and hydrogen reduction are keys to determine surface morphology of micro-channel wall in MCP. In this paper, lead silicate glass micro-channel plates in two different cesium contents (0at%, 0.5at%) and two different hydrogen reduction temperatures (400°C,450°C) were present. The nano-scale morphology, elements content and chemical states of microporous wall surface treated under different alkaline compositions and reduction conditions was investigated by Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS), respectively. Meanwhile, the electrical characterizations of MCP, including the bulk resistance, electron gain and the density of dark current, were measured in a Vacuum Photoelectron Imaging Test Facility (VPIT).The results indicated that the granular phase occurred on the surface of microporous wall and diffuses in bulk glass is an aggregate of Pb atom derived from the reduction of Pb2+. In micro-channel plate, the electron gain and bulk resistance were mainly correlated to particle size and distribution, the density of dark current (DDC) went up with the increasing root-mean-square roughness (RMS) on the microporous wall surface. Adding cesiums improved the size of Pb atomic aggregation, lowered the relative concentration of [Pb] reduced from Pb2+ and decreased the total roughness of micro-channel wall surface, leading a higher bulk resistance, a lower electron gain and a less dark current. Increasing hydrogen reduction temperature also improved the size of Pb atomic aggregation, but enhanced the relative concentration of [Pb] and enlarged the total roughness of micro-channel wall surface, leading a higher bulk resistance, a lower electron gain and a larger dark current. The reasons for the difference of electrical characteristics were discussed.