Study of solid-conversion gaseous detector based on GEM for high energy X-ray industrial CT

Abstract

The general gaseous ionization detectors are not suitable for high energy X-ray industrial computed tomography (HEICT) because of their inherent limitations, especially low detective efficiency and large volume. The goal of this study was to investigate a new type of gaseous detector to solve these problems. The novel detector was made by a metal foil as X-ray convertor to improve the conversion efficiency, and the Gas Electron Multiplier (hereinafter "GEM") was used as electron amplifier to lessen its volume. The detective mechanism and signal formation of the detector was discussed in detail. The conversion efficiency was calculated by using EGSnrc Monte Carlo code, and the transport course of photon and secondary electron avalanche in the detector was simulated with the Maxwell and Garfield codes. The result indicated that this detector has higher conversion efficiency as well as less volume. Theoretically this kind of detector could be a perfect candidate for replacing the conventional detector in HEICT.

CT Scanning of Structural Characteristics of Glacial Till in Moxi River Basin, Sichuan Province

“…It then obtains the X-ray attenuation coefficient from each voxel, arranges them into a digital matrix, applies a digital converter to convert the numbers in the matrix into black, white and gray squares (pixels), and finally, the pixels are arranged in a matrix to form CT Scanning images. Thus, the essence of a CT image is a reconstructed image of the substance [19][20][21]. The process of CT scan image processing is shown in Figure 6.…”

“…in a matrix to form CT Scanning images. Thus, the essence of a CT image is a reconstructed image of the substance [19][20][21]. The process of CT scan image processing is shown in Figure 6.…”

Comparative Study of Seismic Ground Motion Parameters in Deep-Cut and High-Fill Engineering before and after Ground Leveling

“…Due to the needs of the approval process to carry out construction projects in China ,the seismic safety evaluation has been finished mainly based on the original topography in the early stages of construction planning review. But the construction of the building is built in the site after ground leveling, and there are excavation foundation and fill foundation, and the filling thickness varies [1][2][3]. Comparing to soil structure of untreated site in the period of the seismic safety evaluation, the stratigraphic conditions of the various types of buildings built on high fill foundations has changed .…”