扫描电镜工作距离和加速电压与图像清晰度的关系研究

The relationship between the image definition of SEM and different work distances and accelerating voltages of electron beam

为阐明工作距离和电子束加速电压对扫描电镜图像清晰度的影响,实验比较了在不同的工作距离和加速电压条件下,大肠杆菌的扫描电镜图像清晰度和分辨率。并通过理论分析得出：工作距离缩短能加大入射角,导致图像分辨率提高;提高加速电压可增加样品中的二次电子发射,从而提高图像的清晰度,不过加速电压要适当,过低或偏高都会影响图像清晰度。

In order to make clear the effect of different work distances and accelerating voltages of electron beam on the image definition of SEM,the paper compared the images of Escherichia coli under different work distances and accelerating voltages of electron beam with scanning electronic microscopy.The results indicated that shortening the distance between the sample and the object lens can widen the incident angle,which can improve the image definition;the outcomes of the experiment also showed that increasing the accelerating voltage of electron beam can stimulate the sample to emit more secondary electrons,which can make the image more legible.