Development of a soft X-ray tomography device with variable field of view for plasma diagnostics

1.带前置放大器的小尺寸二极管列阵研制由高63 mm×宽26 mm×深69 mm的小尺寸二极管列阵和高时间分辨率的前置放大器组成的五个小尺寸列阵。二极管阵列采用离子注入的方法由硅片制成。每个二极管阵列有20个通道。这些带有前置放大器的小尺寸二极管阵列的时间分辨率小于5微秒，足以用于等离子体诊断。利用调幅样品光(波长850 nm)的时间响应测量了样品光的时间演化。每个通道之间的串扰水平是用光斑(直径0.1 mm)测量的。串扰电平的测量值小于1%，并且该值对于这些二极管阵列的空间分辨率并不重要。可变视距软X射线针孔相机的研制五个针孔相机，用于软X射线，具有可变视野，其中…并在WT-3托卡马克上对这些小孔相机进行了测试。在最大视场范围内，针孔相机可以观测到整个WT-3托马克等离子体，视场范围可以连续变化到最小视场范围。在最小的视场范围内，针孔摄像机可以观察到半个等离子体。计算机层析成像计算程序的研制开发了一个用于分析5个端口，即100个通道的数据的计算程序。重建的方法是傅里叶样条法，在WT-3.4的三端口计算机层析成像中得到了满意的结果。软X射线层析成像装置的测试在具有两种磁流体振荡的WT-3托卡马克等离子体中，可以观察到清晰的低噪声信号。重构检测到的信号。从重建的图像中提供了有关振荡位置和结构的信息，可以肯定这两种类型的MHD振荡分别具有M=1和2的结构。较少

1. Development of small size diode array with pre-amplifiers Five small size diode arrays with pre-amplifiers (height 63 mm X width 26 mm X depth 69 mm) which are composed of small size diode arrays and pre-amplifiers with high time resolution, are developed. The diode array are made of silicon wafer by use of the ion-plantation method. Each diode array has 20 channels. The time resolution of these small size diode arrays with pre-amplifiers is less than 5 mus and is sufficient for plasma diagnostics. The time evolution is measured with time response for amplitude modulated sample light (wavelength 850 nm). The level of cross talk among each channel is measured with pin-spot light (diameter 0.1 mm). The measured value of the level of cross talk is less than 1% and this value is insignificant for the spatial resolution of these diode arrays.2. Development of a pinhole camera for soft X-ray with variable range of view. Five pinhole cameras for soft X-ray with variable range of view, whic … More h can equip the small size diode arrays with pre-amplifiers, are developed The test of these pinhole cameras is carried out on the WT-3 tokamak. In the maximum range of view, the pinhole cameras can observe the whole of the WT-3 tomakak plasma and the range of view can be changed continuously down to the minimum range of view. In the minimum range of view, the pinhole cameras can observe the half of the plasma.3. Development of a calculation code for computer tomography A calculation code for analysis of data from 5 port , that is, 100 channel is developed. The method of reconstruction is Fourier spline method which give satisfactory results in 3 port computer tomography on WT-3.4. Test of the device for soft X-ray tomography The clear signal with low noise level can be observed in the WT-3 tokamak plasma which has two types of the MHD oscillation. The detected signal are reconstructed. The information on the position and structure of the oscillations is provided from the reconstructed images and it is sure the two types of MHD oscillations have M=1 and 2 structure, respectively. Less