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在射线探伤中选择最佳的条件可获得正确的缺陷检测结果,目前已对厚度为0.02～2mm的铅、钢,钛和聚乙烯增感屏进行研究,证明固有不清晰度是影响象质的一个重要因素。当采用Co~(60)γ射线源和8Mv直线加速器作为射线源时,如预料一样,固有不清晰度随着增感屏厚度和射线能量的增加而增加。在这两种射线能量之间,一般情况下在可比较的增感屏厚度范围内,钢和钛增感屏的固有不清晰度值最低。若在Co~(60)γ射线源与胶片之间安放一块钢质滤板,所测定的不清晰度曲线的宽度将是不安放滤板时的两倍,这是由于钢质滤板所产生的散射线而形成的几何不清晰度值迭加而造成。
Choosing the best conditions for radiographic inspection leads to the correct detection of defects. Lead, steel, titanium and polyethylene sensitiv- ity screens of 0.02 to 2 mm in thickness have been studied to demonstrate that inherent unsharpness is a factor affecting the quality of the image An important factor. When using Co 60 γ ray sources and 8 MV linear accelerators as the ray source, as expected, intrinsic unsharpness increases with increase in screen thickness and energy of the rays. Between these two ray energies, steel and titanium sensitization screens typically have the lowest inherent inaccuracies over a comparable thickness of the sensitizing screen. If a steel filter plate is placed between the Co ~ (60) γ-ray source and the film, the measured width of the unsharp curve will be twice that of the filter plate, as a result of the steel filter plate The scattering of the formation of the geometric unsharp value caused by superposition.