Ring Coded Aperture Imaging And Digital Reconstruction

X-ray imaging is often used to diagnose inertial confinement fusion (ICF) targets. To explore the hydrodynamic of a laser-drive implosion, both high spatial resolution and fast temporal resolution is needed. Because wavelength of X-ray is very short, the refractive index of most materials is less than 1 and X-ray can be strongly absorbed in air and other media in the X-ray imaging field. So the general lens is difficult to apply. In X-ray imaging field, transmission imaging and reflection imaging is often used. Coded aperture imaging technique stands for transmission imaging. Coded aperture imaging is a preferable imaging scheme in X-ray imaging technique, which provides a method of increasing the signal throughout, being capable of imaging in weak X-ray, while keeping high resolution-capability and high SNR.The objective of the study is to manufacture coded aperture microscope, which is used to gain prefect images of all phases of ICF to go deep into the study of ICF.In fact, coded-aperture imaging includes two steps. In the first step, a great deal of information is collected from the objective using the ring coded-aperture microscope, and then the visible image of the objective is restored and reconstructed using image processing technique or optics processing technique in the second step. In this paper, wiener filter is applied in the reconstruction process.Coded aperture microscope adopts coded aperture imaging technique. The aperture is fabricated using a combination of thick photolithography and electroplating. The annular mask which can be penetrated by X-ray begins by coating a silicon wafer with a layer of SiN by low-pressure chemical deposition. The equipment which can image and diagnose in X-ray fields is applied to inertial confinement fusion (ICF). The spatial resolution of the coded aperture microscope can reach 5-10 um.The coded aperture microscope is successfully used to X-ray diagnose of laser fusion. The experiment indicates that the coded aperture microscope can image successfully, act agilely and have a high spatial resolution, which reach the request. It proves that the design method is accurate and the technics is scientific.