具有时间分辨能力的强流电子束束剖面测量系统

Time-resolved measurement system for electron beam profile of high current LIA

高能强流电子束的束参数测量是加速器研制过程中重要的一项测量工作,由于光学渡越辐射具有时间响应快、分辨率高等特点而被用于测量电子束的具有时间分辨能力的束剖面、发散角、能量等多个参数;通过电子束束参数的时间分辨测量则能够了解电子束产生、输运中的问题,非常有利于加速器的研究与调试。一种具有时间分辨能力的、利用光学渡越辐射进行高能强流电子束束斑测量的系统在中国工程物理研究院被建立起来,并在12MeVLIA的电子束束斑的测量中用于电子束传输研究,该系统拍摄图像的间隔时间最小为10ns,最小的曝光时间为3ns,具有一次可以拍摄8幅图像的能力,并获得了12MeVLIA约100ns内相应的时间分辨的束斑变化情况,观察到了一些过去未观察到的现象,为加速器的研究提供了又一个新测试方法。

The beam parameters of high energy and high current L1A are very important for the debugging work. For its ul-trafast response and high resolution, OTR is used to measure both spatial and angular profiles of an electron beam. A time-resolved measurement result of an electron beam produced by L1A can provide much more detailed information. Such a time-resolved measurement system for electron beam profile using OTR has been developed recently in the Institute of Fluid Physics of CAEP and has been put into practice. Typical time-resolved measurement results of an electron beam produced by 12 MeV L1A are shown in the paper. Many phenomena are observed for the first time. This system can capture 8 frame images at a time in the minimum time interval of 10ns while the exposure time is 3 ns. The frame time interval has 8 levels which change from 10 ns to 1280 ns in power of 2 and the exposure time can change in three levels of 3, 5, 10 ns. The image has a resolution of 1 376 × 1 035 pixels and the object plane size can reach φ80 mm. This system has provided a new measurement method in study of LIA.