Coding metal aperture array plate based high-contrast X-ray pseudo-thermal source

Abstract

A coding metal aperture array plate based high-contrast X-ray pseudo-thermal source comprises an X-ray generator, an X-ray transmission modulation system and a pseudo-thermal X-ray generation system which are arranged in an anti-radiation casing. Broadband thermal X-ray generated by the X-ray generator reaches a broadband beam limiting diaphragm of the X-ray transmission modulation system through transmission firstly, then the X-ray after beam limiting enters a monochromator and becomes narrowband X-ray after passing the monochromator, the narrowband X-ray after being subjected to beam limiting via a narrowband beam limiting diaphragm is irradiated to the pseudo-thermal X-ray generation system, then the X-ray sequentially passes through a coding aperture plate and a metal aperture array plate, dynamic X-ray speckles are formed in the rear of the metal aperture array plate under control of a metal aperture array plate movement controller, the dynamic X-ray speckles exit via an X-ray exit window in the anti-radiation casing, and accordingly an X-ray pseudo-thermal light field is formed. The coding metal aperture array plate based high-contrast X-ray pseudo-thermal source has the advantages of X-ray band applicability, high contrast, high resolution, high brightness and adjustability.

Description

technical field [0001] The invention relates to an X-ray light source, in particular to a high-contrast X-ray pseudoheat source based on a coded metal hole array plate, which can be used as an X-ray light source in the field of X-ray intensity correlation imaging. Background technique [0002] In intensity-correlated imaging applications, an important issue is the need to obtain a detectable thermo-optic field. For the short coherence time of thermal light, the existing photodetectors cannot measure the instantaneous intensity of thermal light fluctuations. In 1964, Martienssen et al. invented a continuous pseudothermal light source [see W.Martienssen and E.Spiller, "Coherence and Fluctuations in Light Beams", American Journal of Physics 32, 8 (1964)]. In 2006, in order to overcome the problem that the continuous pseudothermal light source does not meet the cross-spectrum purity conditions of the real thermal optical field, Han Shensheng and others from the Shanghai Institu...

AI Technical Summary

Problems solved by technology

For the short coherence time of thermal light, the existing photodetectors cannot measure the instantaneous intensity of thermal light fluctuations. In 1964, Martienssen et al. invented a continuous pseudothermal light source [see W.Martienssen and E.Spiller, "Coherence and Fluctuations in LightBeams", American Journal of Physics 32, 8 (1964)]

In 2006, in order to overcome the problem that the continuous pseudothermal light source does not meet the cross-spectrum purity conditions of the real thermal optical field, Han Shensheng and others from the Shanghai Institute of Optics and Fine Mechanics of the Chinese Academy of Sciences invented a high-brightness pulsed pseudothermal light source (invention patent No. ZL200710036968.X)

[0003] 1. There is no practical coherent light source for X-rays similar to lasers in the visible light band, and the X-ray coherence time (picosecond level) is far shorter than the response time of existing detectors (nanosecond level);

[0004] 2. The X-ray has a short wavelength and high penetrability. There is no suitable space transformation modulation element, and the ground glass scattering effect cannot be used to obtain pseudothermal speckle.

However, due to the high penetrability and partial coherence of X-rays, the X-ray speckle contrast ratio produced by this microporous film-based X-ray pseudoheat source is only 0.05, and more than 90% of the incident light becomes the noise background, which has no effect on the intensity correlation. The image quality has a great influence

Images