关键词: 分幅变像管/
动态空间分辨率/
调制传递函数
English Abstract
Calibration of the dynamic spatial resolution of framing image-converter
Yuan Zheng,Dong Jian-Jun,
Li Jin,
Chen Tao,
Zhang Wen-Hai,
Cao Zhu-Rong,
Yang Zhi-Wen,
Wang Jing,
Zhao Yang,
Liu Shen-Ye,
Yang Jia-Min,
Jiang Shao-En
1.Reserch Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Fund Project:Project supported by the Development Foundation of China Academy of Engineering Physics (Grant No. 2014B0102010).Received Date:21 December 2015
Accepted Date:09 February 2016
Published Online:05 May 2016
Abstract:In order to improve the two-dimensional imaging diagnostic accuracy of inertial confinement fusion (ICF) experiment, a calibration method of the dynamic spatial resolution of X-ray framing image-converter (XFIC) is proposed. When an object with straight edge function is projected onto the photocathode of XFIC as an input, edge spread function can be obtained by recording an image of the XFIC output. The first derivative of the edge spread function produces the line spread function (LSF). Then the modulation transfer function (MTF) of the system can be worked out by Fourier transform of the LSF. Therefore, the spatial resolution can be deduced. According to this theory, the spatial resolution of XFIC can be obtained. Based on SG-Ⅱ laser facility, the calibrating X-ray source is generated by 8 bundled lasers bombarding the target. High-Z knife-edge is irradiated by the X-ray and imaged on the photocathode of XFIC, and then a dynamic image is obtained as the system works in the gating mode. By handling the dynamic image, the LSF of XFIC is given by analyzing the edge image. Then the MTF of the camera can be indicated by the Fourier transform of the LSF. When the MTF is 0.1, the corresponding spatial resolution of the imaging system is 20 lp/mm. According to the dynamic spatial resolution theory of framing image-converter, the extreme spatial resolution is 22.8 lp/mm. The calibration result agrees with the theoretical results. By contrast, the static spatial resolution of the same X-ray framing image-converter calibrated by the traditional method is presented here. The calibrated static spatial resolution is 22 lp/mm, a little higher than the dynamic one. During the two-dimensional imaging diagnosis, the X-ray framing image-converter works in the dynamic gating mode, thus the calibrated dynamic spatial resolution can be more truthful to reflect its imaging diagnosis ability.
Keywords: framing image-converter/
dynamic spatial resolution/
modulation transfer function
