A DEVELOPMENT OF X-RAY IMAGER AND POLARIMETER IN WIDE ENERGY RANGES BY GAS COUNTER WITH MICROCHANNEL PLATE

我们用微通道板的双向产物毛细管板研制了一种新型的气体正比计数器，它具有良好的位置分辨和能量分辨能力。毛细管板由一束细小的玻璃毛细管组成，入口和出口上都有电极。该玻璃为铅玻璃，与典型的微通道板相比，具有更高的电阻率。所研究的毛细管直径为100微米，长度为800微米。板的直径有效地为20 mm。卡管板安装在真空密闭气室中，并通过在入口和出口之间施加电压在气体中操作。填充气体为Ar+5%甲烷，充气压力为1L/L。用X射线对毛细管板气体正比计数器(CGPC)的性能进行了研究。由此产生的正比计数器被发现在没有击穿的情况下工作到10^4的增益。气体增益与外加电压的函数关系和汤森电离系数的分析表明，CGPC的电子倍增是由于每个毛细管中的气体倍增所致。当气体密度为7000时，5.9keV X射线的能量分辨率为26%。2.9keV能量的逃逸峰与主峰明显分开。除了开启高压后的前15分钟，CGPC的气体增益在10小时以上的长时间内是稳定的。CGPC的一个要点是气体在每根毛细管中发生倍增，因此进入每根毛细管的电子云的每一部分都在非常小的区域内被识别出来。作为CGPC的一个应用，我们可以用它来探测毛细管中的X射线和部分电子云中的X射线。我们可以从结果中展望精细X射线成像探测器和X射线偏振仪的发展。

We have developed a new type of gas proportional counter with the capability of fine position resolution and energy resolution by using a capillary plate, which is bi-product of a micro-channel plate. The capillary plate consists of a bundle of fine glass capillaries with electrodes on both the inlet and the outlet. The glass is lead glass and has higher resistivity, compared with the typical microchannel plates. The diameter and length of a capillary investigated are 100mum and 800mum, respectively. The diameter of the plate is effectively 20mm. The cappilary plate is installed in a vacuum tight gas chamber and is operated in gas by applying voltages between the inlet and the outlet. The fill gas was argon+5% methane at a pressure of latm.The characteristics of the capillary plate gas proportional counter (CGPC) were investifgated in using _<55>Fe 5.9keV X-rays. The resulting proportional counter was found to operate up to a gain of 10^4 without the onset of breakdown. The gas gain as the function of applied voltage and an analysis of Townsend ionization coefficient indicate that the electron multiplication of the CGPC is due to gas multiplication in each capillary. An energy resolution was 26% for 5.9keV X-rays at a gas gein of 7000. The escape peak in the energy of 2.9keV was clearly separated from the main peak. The gas gain of the CGPC was stable for long term operation over 10hours except during the first 15minutes after turning on the high voltages.An inportant point of the CGPC is that the gas multiplication occurs in each capillary and hence each part of the electron cloud entered in each capillary is identified in a very small domain. As an application of CGPC,we are available it to detect a X-ray in a capillary and a part of a electron cloud. We can envision development of a fine X-ray imaging detector and X-ray polarimeter from the results.