FIR SPECTROSCOPY AND BUNCH SHAPE MEASUREMENT BY COHERENT SYNCHROTRON RADIATION

利用东北大学原子核科学研究室的直线加速器，我们观测了相干同步辐射的基本性质。我们通过用干涉仪观察干涉图样，观察到来自各个束团的光的波包的相干性，并使用高分辨率光谱仪确认了由于干涉引起的光谱精细结构。我们观察到的抑制的相干辐射的平行板的金属的屏蔽效应。对相干跃迁辐射的光谱强度、强度与发射长度的关系、强度的角分布等性质进行了理论分析和研究，以高分辨率在长波长区域观察玻璃材料的固态试样的透射率，直到3 mm，使用100 ns的渡越辐射脉冲和来自加速器的电子束，在从0.2到几mm的波长范围内进行辐解的高速测量。已经证实，相干同步辐射和相干渡越辐射的分析以及给出了电子在聚束中的分布函数，其宽度为0.26 ~ 0.27mm，近似为高斯型，对相干跃迁辐射的角分布进行了分析，并给出了光束的发射度。这些结果表明，相干辐射的观测是皮秒级高分辨率光束诊断的一种新方法。

Using a linear accelerator at Laboratory for Nuclear Science, Tohoku University, We have observed most fundamental properties of coherent synchrotron radiation. We observed the coherence of the wave packet of light from individual bunches by the observation of interference pattern with an interferometer, and confirmed spectral fine structure due to the interference using a high resolution spectrometer. We observed the suppression of the coherent radiation by a shielding effect of parallel plates of metal. properties of coherent transition radiation such as the spectrul intensity, dependence of the intensity on the emission lengths, angular distribution of the intensity have also been investigated and analyzed well by theory.By the coherent transition radiation, the transmission of a solid state specimen of a glass material was observed with high resolution in the long wavelength region to 3 mm and the measurement of transmission was confirmed to be possible up to 5 mm. Using a 100 ns pulse of transition radiation and the electron beam from the accelerator, a high speed measurement of radiolysis was done in the wavelength range from 0.2 to a few mm.It has been confirmed that analysis of coherent synchrotron radiation and coherent transition radiation as well gives the distribution function of the electron in a bunch, which is of almost the Gaussian shape with the width of 0.26 to 0.27 mm. The analysis of the angular distribution of coherent transition radiation also gives the emittance of the beam. These results indicates that the observation of the coherent radiation is a new method of the beam diagnosis with a high resolution of picosecond.