Boivin L P
Appl Opt. 1977 Feb 1;16(2):377-84. doi: 10.1364/AO.16.000377.
The diffraction corrections associated with a circular aperture are calculated for the case of a point source and a detector aperture having a diameter approximately equal to that of the illuminated region. This investigation is made for monochromatic and complex (tungsten) radiation; two types of detectors are considered: a typical silicon diode and a neutral detector. The intensity distribution near the edge is calculated for the same cases. Some experimental results are also presented to corroborate the calculations and to suggest the behavior with extended sources. We show that strong diffraction effects are present close to the shadow edge even with a source-detector combination having a very extended wavelength band. In radiometric measurements, a suitable compromise between diffraction effects, stray light, and vignetting effects can be achieved by having the detector aperture diameter approximately half that of the illuminated region. An extended source will reduce diffraction effects. Finally, some suggestions are made with respect to making diffraction corrections for a series of apertures.
针对点光源以及直径近似等于照明区域直径的探测器孔径的情况，计算了与圆形孔径相关的衍射校正。本研究针对单色辐射和复合（钨）辐射进行；考虑了两种类型的探测器：典型的硅二极管和中性探测器。针对相同情况计算了边缘附近的强度分布。还给出了一些实验结果，以证实计算结果并表明扩展源的行为。我们表明，即使在源 - 探测器组合具有非常宽的波长范围时，在阴影边缘附近也存在强烈的衍射效应。在辐射测量中，通过使探测器孔径直径约为照明区域直径的一半，可以在衍射效应、杂散光和渐晕效应之间实现合适的折衷。扩展源将减少衍射效应。最后，针对一系列孔径的衍射校正提出了一些建议。
