基于CT算法的束团横向相空间测量

Transverse Phase Space Measurement Based on Computerized Tomography

精确测量束团的发射度和横向相空间,在高亮度电子束的产生和应用中具有重要意义．传统测量方法在测量发射度时需要对束团在相空间内分布进行初始假设,且只能给出相椭圆的twiss参数；基于CT(computerized tomography)算法的束团横向相空间测量方法无需先验假设,能给出粒子在相空间内的真实分布,测量结果更为精确．介绍了基于CT算法的束团横向相空间测量的原理和初步实验结果,并与四极透镜扫描法测量的结果进行了比较．

Precise measurements of emittance and transverse phase space are essential to generation and applications of high brightness electron beams. Compared to the quadrupole-scanning technique which treats the phase space distributions as ellipses and only measure the sigma matrices that define the ellipses, the measurement of transverse phase space based on CT（computerized tomography） measures the actual phase space distributions while making no a priori assumptions about the distributions. This process is capable of reconstructing transverse phase space distributions that are not elliptical. The theories of CT based measurements are studied. The preliminary experiment result is presented which is in good agreement with that obtained from quadruple scanning.