Libera数字束流位置处理器在工作点测量中的应用

Application of digital beam position processor Libera on tune measurement

数字信号处理技术在现代束流诊断中有成熟的应用,特别是在束流位置检测器信号分析和工作点测量时有优越的性能。在合肥光源工作点测量中,采用高斯白噪声激励起束流横向振荡,再利用Libera数字束流位置处理器采集激励后的束流位置信号,并进行幅度解调得到束流横向振荡频率,再利用Matlab进行快速傅里叶分析处理,得到工作点的小数部分,从而实现工作点测量。在合肥光源上进行实验,测量得到其水平工作点是3.535 2,垂直工作点是2.629 9。

Digital signal processing （DSP） is widely used in the field of beam diagnostics. Especially, DSP achieves very good performance in beam position signal analysis and betatron tune measurement. In Hefei light source, when beam was excited by narrow-band Gaussian white noise, Libera, a digital beam position processor, was used to process the signals from beam position monitor （BPM）, which contained betatron oscillation. Fast Fourier transform （FFT） was applied to finding out betatron resonance frequency, from which the decimal part of betatron oscillation tune was calculated. By this means, the measure of horizontal tune was 3. 535 2 and the measure of vertical tune is 2. 629 9.