The development of gas-sealed type position-sensitive counter utilizing peculiar electron-avalanche mode

在这项研究中，我们为利用特殊的电子雪崩模式研制气密型位置灵敏计数器做了基础研究。(1)有限比例区高压正比计数器的工作机理和性能(A)详细分析了由于特征X射线引起的晕效应，并对这种效应引起的正比计数器的响应进行了充分的解释。首次发现在RLP中，晕事件的气体放大程度大于光峰事件。从实际的观点来看，这一事实是有帮助的，因为简单的脉冲高度选择能够排除已知会降低位置分辨率的晕事件。研究结果发表在第号文章。(1)。(B)在带电粒子加速器实验中验证了位置灵敏正比计数器的可行性。结果表明，高烯…(2)(C)证实了在7-ATM Ar+30%CH_4中存在由初级电子云结构变化引起的雪崩模式突变。(3)(D)在KEK光子工厂测试了PSPC对10-60keV高能光子束的性能。获得了较好的位置分辨率，20-keVX射线的位置分辨率为122um(Fwhm)，35-keVX射线为140um。文章(4)给出了部分结果。(E)最近，用6 MeV质子束轰击多个目标，使用我们的PSPC所配备的晶体光谱仪进行了高分辨率X射线测量。结果揭示了反常的峰结构，清楚地显示了原子体系的多体效应。在本研究项目的进一步完善中，我们完成了新改进的PSPC、除氧除水的气体净化系统和改变计数气体和混合比例的气体混合系统的建设。气体系统与无油涡轮分子泵相结合。对于Ar气体，当气体被密封在PSPC中时，获得了较好的性能；而对于Xe气体，需要改进气体系统，特别是气体净化系统的性能。较少

In this research, we have made basic studies for the development of gas-sealed type position-sensitive counter utilizing peculiar electron-avalanche mode. Our achievements are as follows :(1) Operational mechanism and performance of high-preessure proportional counter in the region of limited proportionality (RLP) (a) Detailed analysis was performed for the halo effect due to characteristic X rays, and the response of proportional counter caused by this effect was fully explained. It was first found that, in RLP,the degree of gas amplification for the halo events is greater than that for the photo-peak events. From the practical view-point, this fact helps since a simple pulseheight selection is able to exclude the halo events which is known to deteriorate position resolution. The results are published in the article No. (1). (b) The feasibility of our position-sensitive proportional counter (PSPC) was examined in charged-particle accelerator experiment. The result showed that high-ene … More rgy (position) resolving power of the PSPC enables to analyze trace elements to be studied in PIXE.(the article No.(2)) (c) It was confimed that the sudden change of avalanche mode due to strutural change of primary-electron cloud exists in 7-atm Ar+30% CH_4. (the article No.(3)) (d) The performance of the PSPC for 10-60 KeV high-energy photon beams was tested in KEK Photon Factory. Fairly good position resolitions of 122mum (fwhm) for 20-keVX rays and 140mum for 35-keVX rays were obtained. A part of the results is given in the article No.(4). (e) Recently, high-resolution X-ray measurement using crystal spectrometer equipped with our PSPC was made by bombarding several targets with 6-MeV proton beams. The results reveled anomalous peak structures which clearly show many-body effect of atomic system. The elaborate analysis is being proceeded to publish paper as soon as possible.(2) Further improvement In this research project, we have completed to construct a newly improved PSPC,gas purification system to remove oxygen and water, and a gas mixing system to vary counting gases and mixing ratio. The gas systems are combined with oil-free turbo molecular pump. For Ar gas, relatively good performance was obtained when the gas is sealed in the PSPC.For Xe gas, however, it is needed to improve gas system especially the performance of the gas-purification system. Less