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X射线光栅干涉仪成像需要高条纹可见度以获得高信噪比图像. 最近的报道证实, X射线双矩形相位光栅干涉仪实验测量的条纹可见度较低. 为此, 提出了基于研究. 利用X射线双相位光栅干涉仪的强度变化规律, 对比研究了单色照明和不同多色照明下, 双三角形相位光栅X射线干涉仪与双矩形相位光栅干涉仪的条纹可见度随光栅间距的变化规律. 结果表明: 无论是单色照明还是多色照明, 的峰值随相移量的增加而增大. 当相移量为5π/2时, 在单色照明下比双矩形相位光栅干涉仪的条纹可见度提高约21%, 在多色照明下提高至少23%. 而在多色照明下, 随着X射线平均能量偏离光栅设计能量的增加或光源焦点尺寸的增加, 双相位光栅干涉仪条纹可见度的峰值均会单调下降. 这些结果可作为X射线双相位光栅干涉仪的参数设计和性能优化的理论指导.In recent years, the X-ray interferometer using dual phase gratings has been extensively studied. The large periodic fringes produced by the X-ray interferometer using dual phase gratings can be directly detected by ordinary detectors. At the same time, the X-ray interferometer using dual phase gratings can reduce the radiation dose of the sample without using absorption gratings. Meanwhile, a high fringe visibility is always preferred to achieve a high signal-to-noise ratio for X-ray grating interferometry. However, recent studies have reported that experimental fringe visibility in X-ray interferometer using dual rectangular phase gratings is relatively low. Therefore, it is necessary to further increase the fringe visibility in X-ray interferometry using dual phase gratings. This work focuses on the analysis of fringe visibility in X-ray interferometer using dual triangular phase gratings. Based on the fringe intensity distribution formula of X-ray dual phase grating interferometer, the fringe visibility of the dual triangular phase grating interferometer is investigated as a function of the grating spacing under monochromatic and polychromatic illumination, respectively. For comparison, the fringe visibility of the dual rectangular phase grating interferometer is also studied under the same condition. The results show that the maximum fringe visibility of the dual triangular phase grating interferometer increases with the phase shift increasing regardless of monochromatic or polychromatic illumination. Under monochromatic illumination, the maximum fringe visibility of dual 5π/2 triangular phase gratings is about 21% higher than that of dual rectangular phase gratings. Under polychromatic illumination, the fringe visibility of dual 5π/2 triangular phase gratings is at least 23% higher than that of dual rectangular phase gratings. Under polychromatic illumination, the greater the deviation of X-ray average energy from the grating design energy, the greater the decrease of maximum fringe visibility of the dual phase grating interferometer is. In addition, with the increase of the focal size of X-ray source, the maximum fringe visibility of the dual phase grating interferometer decreases, under polychromatic illumination. We hope that those results can be used as guidelines for designing and optimizing X-ray interferometer using dual triangular phase gratings.
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参数 双三角形相位光栅 双矩形相位光栅 π/2 π 3π/2 2π 5π/2 π/2 π $ {V_{\text{p}}} $ 0.25 0.48 0.64 0.68 0.74 0.34 0.61 s/mm 9.8 6.6. 4.8 3.7 3.0 10.8 3.7 W/mm 12.1 9.1 5.8 4.9 3.4 12.0 3.8 
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参数 双三角形相位光栅 双矩形相位光栅 π/2 π 3π/2 2π 5π/2 π/2 π $ {V_{\text{p}}} $ 0.25 0.41 0.56 0.58 0.63 0.30 0.51 s/mm 9.1 6.5 4.5 3.6 2.8 10.9 3.5 W/mm 12.3 10.4 6.8 5.5 4.2 15.0 4.0 下载:
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光源峰值电压/kV 参数 双三角形相位光栅 双矩形相位光栅 π/2 π 3π/2 2π 5π/2 π/2 π 55 $ {V_{\text{p}}} $ 0.20 0.32 0.37 0.41 0.42 0.22 0.28 s/mm 67.9 37.3 35.6 26.7 19.5 25.7 37.3 W/mm 117.3 96.3 81.5 69.3 67.6 44.8 52.9 75 $ {V_{\text{p}}} $ 0.14 0.27 0.31 0.34 0.37 0.16 0.25 s/mm 71.0 40.1 38.9 29.4 27.5 26.7 37.4 W/mm 116.7 105.7 96.6 85.8 79.9 51.8 53.6 95 $ {V_{\text{p}}} $ 0.11 0.20 0.26 0.29 0.32 0.13 0.22 s/mm 76.5 41.4 45.4 43.6 32.1 26.7 38.8 W/mm 116.7 111.3 104.1 98.3 92.1 55.3 54.1 下载:
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光源焦点尺/µm 参数 双三角形相位光栅 双矩形相位光栅 π/2 π 3π/2 2π 5π/2 π/2 π 7 $ {V_{\text{p}}} $ 0.20 0.32 0.37 0.41 0.42 0.22 0.28 s/mm 67.9 37.3 35.6 26.7 19.5 25.7 37.3 W/mm 117.3 96.3 81.5 69.3 67.6 44.8 52.9 25 $ {V_{\text{p}}} $ 0.14 0.25 0.31 0.34 0.38 0.17 0.17 s/mm 48.6 35.0 28.3 24.9 21.6 21.5 28.3 W/mm 75.8 66.2 61.3 57.5 54.5 34.3 43.3 40 $ {V_{\text{p}}} $ 0.10 0.19 0.26 0.31 0.34 0.12 0.11 s/mm 36.2 29.2 24.1 21.1 19.3 17.9 21.1 W/mm 52.5 49.1 46.3 44.1 42.3 27.9 25.4 下载:
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