荫罩式平板探测器的探测性能与优化

Improvement of Novel Shadow-Mask Flat Panel Detector

荫罩式平板探测器是在等离子体显示器的基础上发展的一种新型气体探测器。该探测器可以继承等离子体的制作工艺,具有结构简单,制造成本低,易于实现大面积探测等优点。本文主要通过模拟荫罩式平板探测器内的电子倍增过程,研究了这种气体探测器的探测性能。从荫罩结构、电极宽度和荫罩高度入手,对探测器的结构进行优化。结果表明:将荫罩拓展到介质层对增益影响不大,适度调整荫罩高度,减少阴极宽度是改善平板探测器的探测特性的有效途径。在单元采用直孔荫罩结构,阴极宽度为120μm,单元宽600μm,荫罩高300μm时,阳极施加600 V电压,有效增益和实际增益分别为60和342。

Here, we addressed the optimized design of a novel type of shadow-mask flat panel detector, with its structures and fabrication technologies closely resembling to those of a plasma display panel （PDP）. The behavior of parti- cle in the cell,particularly the electron avalanche, was modeled,and simulated with 2-D software package based on PIC- MCC. The influence of major factors, including the height and structure of the shadow mask and electrode width, on the gain was calculated. The simulated results showed that the detector gain strongly depends on the shadow-mask height and cathode width,but weakly on the expension of the shadow mask onto the dielectric layers. In a 600 μm wide-cell with straight shadow-mask height of 300 μm and a cathode width of 120 μm, the effective gain and realistic gain, biased at 600 V, were found to be up to 60 and 342, respectively.