Study On High-precision Automatic Monitoring System For The Synchronization Of Accelerator

The ion accelerators are used to generate high-speed ion beams artificially,which is important for exploring fundamental interaction forces and looking into the structure of matter and the evolution of the universe,as well as developing advanced nuclear technologies that are relevant to socio-economic development and national security.Several ion accelerator facilities that are very different are designed and constructed by the Institute of Modern Physics,Chinese Academy of Sciences,including Heavy Ion Research Facility in Lanzhou(HIRFL-CSR),Space Environment Simulation and Research Infrastructure(SESRI),Proton Radiation Effects Facility(PREF),etc.Those facilities consist of a lot of hardware systems,like power supplies,radio frequency cavities,controls and so on,while all hardware systems are made up of many kinds of hardware.As the ramping rate of magnetic field becomes larger and larger,the synchronization between all hardware has much more detrimental impacts on the beam commissioning,operation,and the facility performance.It is necessary to measure and correct the synchronization of all accelerator hardware.Now,synchrotrons usually employ single-point synchronization measurement algorithm to fix the synchronization.But the algorithm only takes few moments in the readback waveform to compare with the ones in the theory waveform.Because only very little data is included in this algorithm,the algorithm could be influenced by hardware output precision,hardware noise,and acquisition system noise seriously,which leads to very unprecise measurement results,just about millisecond level.The single-point synchronization measurement algorithm cannot meet the synchronization requirements in the non-resonant rapid-cycling accelerators.To improve the beam commissioning efficiency and achieve better beam quality,this paper proposes a waveform matching-based synchronization measurement algorithm,which employs all readback waveform points to compare with the theory waveform points and can reduce the influence of noise and measurement errors.Compared with the single-point waveform matching algorithm,the waveform matching-based synchronization measurement algorithm has obvious advantages in measurement accuracy and reliability of automatic measurements.Based on this algorithm,an automatic synchronization measurement system for the whole accelerator facility is designed and developed in this paper.All hardware devices are synchronized by the new algorithm to a fixed time tick to calculate the delay time between each other.By adjusting the delay times to specific values,the synchronization of all hardware devices in the facility is achieved.It is necessary to verify that the new waveform matching-based synchronization measurement algorithm and the whole-facility automatic synchronization measurement system developed based on this algorithm are ready for deploying in the real machines,and they are very reliable for automatic measurements.So,a whole-facility automatic synchronization measurement system is built in the SESRI,a major infrastructure project of the National Twelfth Five-Year Plan.The system corrects the synchronization between the SESRI hardware devices to about 15 μs,and greatly improves the commissioning efficiency and performance of the SESRI.All results show that the automatic synchrotron measurement system can significantly improve the accuracy and the real-time capability of the synchronization measurements,which makes it possible to measure the synchronization of non-resonant rapid-cycling accelerators quickly and accurately.In the future,the waveform matching-based synchronization measurement algorithm and the whole-facility automatic synchronization measurement system will be widely used in the PREF,the next-generation heavy ion therapy facilities,and other non-resonant rapid-cycling accelerator facilities.