A Transverse Beam Size And Position Measurement System Based On Oscilloscope

In the electron storage ring,the transverse beam size and position of the electron beam both are the important parameters to evaluate the status of the electron beam.Not only can we monitor the running status of the electron beam,but also can study the instability of the electron beam,to facilitate further optimization of accelerator performance and machine upgrades by measuring the transverse size and position of the electron beam.The traditional transverse section measurement system chooses the CCD camera as the photoelectric detector,but because of the low frame rate of the CCD camera,the measurement result is often the average measurement result of many circles or many bunches,it is not possible to make a fast measurement of the transverse size of the beam on a turn-by-turn or on a bunch-by-bunch basis.Considering the practical need of transverse beam measurement and diagnosis in the storage ring light source,multi-anode Photomultiplier tubes MAPMT with higher conversion rate is used as the photoelectric detector,a fast beam transverse size and position measurement system based on wideband oscilloscope sampling is designed for HLS-Ⅱ storage ring light source.In this paper,firstly,the research situation and development in the field of fast beam lateral size and position measurement are investigated through a large number of literatures.In this paper,a logarithmic processing algorithm is used to extract the transverse dimension and position of the light spot,which is different from the research and analysis of foreign laboratories which use the Photomultiplier tubes to output up to a dozen optical signals at the same time,the design cost and complexity of the experimental measurement system are greatly reduced by only Photomultiplier tubes four continuous channels of photo voltage signal.Secondly,the construction of the fast beam cross section measurement system is introduced,including the fast conversion photoelectric detector,optical imaging system,signal acquisition system and data processing modules.For the optical part,we designed the magnification ratio in both directions of the imaging optical path,and used the direct imaging method of synchrotron light to magnify and image the spot,and used the multi-anode Photomultiplier tubes made by Hamamatsu for the fast photoelectric conversion detector,the rise time is 0.6 ns and the bottom width is about 4 ns,which can satisfy the requirement of 4.9 ns of HLS-Ⅱ bundle spacing,and the D-type slot assembly E6736 is chosen as the high voltage power supply circuit of the Photomultiplier tubes,select the PS300 series of SRS high-voltage power supply module PS310 as MAPMT high-voltage power supply voltage.Then,the oscilloscope with high bandwidth and high sampling rate is used to collect the signal,and the data collected by the oscilloscope is resampled to extract the peak value of the beam signal by MATLAB,finally,the position and transverse size of the beam are calculated by the logarithmic processing algorithm.The logarithmic processing algorithm is introduced,and the relationship between size signal and spot size,and between position signal and spot position is obtained by numerical simulation.Because of the channel difference of MAPMT,the algorithm is modified by using the beam transverse size information measured by CMOS.Then,a data processing system based on high-speed oscilloscope is built,and the data collected by the oscilloscope is resampled and the signal amplitude is extracted by using MATLAB software,and the logarithmic processing algorithm is used,the transverse size and position of the bunches are calculated,and the transverse size and position of bunches in the case of multiple loops are analyzed.