Experimental Method And Gratings Related Research On Grating Based X-ray Phase-contrast Imaging

X-ray is a kind of strong penetrability and invisible short wavelength radiation, its imaging performance is a kind of effective detection methods. Scientists are constantly researching on X ray imaging more than one hundred years, and successfully expanding the scope of the application domain. X-ray imaging can reveal the internal structure of the material through their difference on absorption performance, which make great sense on the fields of medical diagnosis and industrial inspection. When we put forward the demand of observation of materials which are composed of light elements, researchers develop new theory called X-ray phase-contrast imaging which combines X-ray’s penetrability and phase-shift characteristic.Nowadays there are several developed X-ray phase-contrast imaging methods, but many of them are limited within the laboratory and Large scientific devices. While Geometric projection gratings based X-ray phase-contrast imaging solves the dependence on the high level light source, can get widely studied in conventional experimental conditions and obtain strong expectations on practical use. The grating imaging components plays a key role in efficiency, energy level and quality of imaging, this dissertation is carried out on the following work of structure design and quality detection of gratings:1. Optimize data collection procedures and imaging methodDue to the mismatching between image acquisition module of the CCD detector and the grating mobile platform, it waste a lot of time to carry out the experiment. Write automatic acquisition program through the dynamic link library of Labview development kit to implement coordinated operation of gratings, sample stage and CCD detector. Carry out experiment by bucket integral method to improve the stability of mechanical system, effectively reduce radiation dose.2. Development on grating components of X-ray phase-contrast imaging setupCombining LIGA technology and ultraviolet exposure technology, Grope process of high aspect ratio and large grating. Aiming at questions on grating grooves’collapse, warp, breakage, shedding phenomenon, we improve the processing technic and design high strength structure. We analyze the feasibility through the finite element simulation and reduce the damage of pattern by adjust the progress of development, rinse and dry.3. Research on the impact of grating quality on X-ray phase-contrast imagingBased on the data processing of sample’s background image, we find a special phenomenon which is very different from conventional absorption signal, that refraction information reflect big abnormal stripes. We design experiment to find what causes this result, and finally come to the conclusion that the remnants of the SU-8 photoresist brings the abnormal refraction signals. And we further put forward a solution of nondestructive testing of high precision components and write the patent.This article provides some research experience. In terms of grating development process, Finite element analysis can help save a lot of time and materials costs to test new structures. The detection capability of X-ray phase-contrast imaging give a way to test grating quality and internal structure, and feedback to improve the manufacturing process.