Application of the Intense Coherent Radiation to Far-Infrared Spectroscopy and Development of Accelerators

高能短电子束相干辐射在亚毫米波到毫米波波长范围内具有连续光谱，辐射强度高。本文将相干辐射光源应用于吸收光谱学。通过优化直线加速器的工作条件，大大提高了相干跃迁辐射的强度和稳定性。吸收光谱系统的波长范围为0.3-2 mm，波长分辨率为1%。对固体和液体样品的吸收系数和折射率由通过样品的光的测量光谱得到。建立了一种窄光束成像系统。获得了该系统的基本特性，并对一些生物材料和薄金箔纸进行了成像实验。用脉冲光激发固体表面，观察表面反射后的光谱。得到了脉冲辐射分解实验的基本特征。利用条纹相机和相干辐射光谱仪监测系统测量了电子束的形状。测量结果表明，束束形状一般为三角形。为了从电子束中获得较强的电场以实现未来的尾流场加速器，在该系统的监测下对电子束形状进行了优化。

The coherent radiation from high-energy short electron bunches has a continuous spectrum in a submillimeter to millimeter wavelength range and is highly intense. In this work the coherent radiation light source has been applied to absorption spectroscopy.The intensity and the stability of the coherent transition radiation have been considerably increased by optimizing the operational conditions of the linac. The wavelength range and the wavelength resolution of the absorption spectroscopy system are 0.3-2 mm and 1%, respectively.For solid and liquid samples the absorption coefficient and the refractive index have been obtained from the measured spectra of light passing the sample. An imaging system using a narrow light beam has been established. Basic characteristics of the system have been obtained and imaging experiments have been performed for some biomaterials and thin gold print on a sheet of paper. A solid surface has been excited with the pulsed light and spectrum of the light after the reflection at the surface has been observed. The basic features of the pulse radiolysis experiments have been obtained.The electron bunch shape has been measured with a monitoring system using a streak camera and spectrometer of the coherent radiation. The results of the measurement have shown that the bunch shape of the beam is generally triangular. To obtain relatively strong electric field from the electron bunch for realizing future wake-field accelerators the bunch shape has been optimized under being monitored with this system.