Coherent optical transition radiation (COTR) from femtosecond electron bunches is simulated using an earlier proposed model. It is shown that partial screening of the COTR field followed by focusing with a lens allows increasing the spatial resolution and makes it possible to measure transverse bunch sizes accurate within a few microns. It is demonstrated that the most reasonable lens screening ratio equals to 50%. Given this, it is possible to eliminate the ring-like structure typically observed on bunch images as a result of coherence.

中文翻译：

---

相干光跃迁辐射的部分聚焦和飞秒电子束的横向尺寸测量

飞秒电子束的相干光跃迁辐射（COTR）使用较早提出的模型进行了模拟。结果表明，对COTR场进行部分屏蔽，然后用透镜聚焦，可以提高空间分辨率，并可以测量几微米以内的横向束尺寸。事实证明，最合理的镜片遮挡率等于50％。鉴于此，有可能消除由于相干而通常在束图像上观察到的环状结构。