Design And Application Of The Beam Loss Monitoring System For The Storage Ring Of SSRF

The beam loss monitoring system (BLM system) is designed for measuring beam loss around accelerator. The BLM system is widly used in today's accelerators as a beam diagnostic and machine protection tool.Shanghai Synchrotron Radiation Facility (SSRF) is the first third-generation synchrotron radiation light source built in Chinese mainland. The 3.5GeV electron energy is fourth in the world.This thesis has built a new BLM system for the storage ring of SSRF. This BLM system can provide the beam loss distribution along the storage ring, which is affected by machine parameters and status. So the information from BLM can be an interesting clue for finding the problem such as vacuum leakage, improving the machine performance and so on.The beam loss mechanism is studied in the thesis, followed by beam dynamics analysis which gives the location of lost particles along SSRF storage ring. A detailed beam trajectory tracking with the DBA structure of SSRF storage ring under different energy loss ratios also helps to predict the appropriate positions of beam loss monitoring.The beam loss mechanism points out that when particles hit the vacuum chamber wall a shower process occurs. Among this process, shower electrons carry more distinct position information of lost particles than photos and neutrons do. The PIN photodiode BLM detector originally designed at DESY is then employed in this situation for detecting the shower electrons, which is sensitive to shower electrons, but nearly has no response to photos and neutrons. A Monter-Carlo calculation gives the shower election distribution outside the vaccum pipe surface, helping to fix the accurate detecting position for BLM detectors around the beam pipe.The detectors are installed along the 432 meter ring, most of them are located at the appropriate positions given by calculation and few are mobile to provide more flexibility. A distributed data acquisition system based on embedded system and synchronous ethernet technology is also designed to collect the signals from all the detectors and transfer to the data storage and analyse workstation.The BLM System described in this thesis has been built and contributed to the commissioning of the SSRF storage ring, and been qualified as a sensitive and steady machine diagnostic and radiation protection tool.