The design of Hefei advanced light facility timing system

Abstract

BackgroundHefei Advanced Light Facility (HALF) is a fourth-generation synchrotron radiation light source based on diffraction-limited storage ring. The timing system provides trigger signals for the HALF injector, storage ring and beamline, coordinates injection and beam measurement, and achieves filling of the storage ring bucket with any designated bunch pattern.PurposeThis study aims to design a timing system for HALF to reduce the trigger signal jitter of the HALF device to less than 30 ps, and stabilize the signal drift caused by the optical fiber length change.MethodsBased on the MTCA.4 event-driven products from Micro-Research Finland Oy (MRF), the event timing technology scheme was adopted to implement the timing system. Appropriate system frequencies for electron gun, microwave system and storage ring were selected to achieve different modes of storage ring bucket filling scheme. The timing system software was developed under Experimental Physics and Industrial Control System (EPICS) to coordinate with the control system of HALF, including an EPICS driver, database records, and operation interfaces. Delay compensation was applied to signal drift caused by the variation of optical fiber length. Finally, a prototype of the timing system was developed for performance tests.Results & ConclusionsThe results show that the jitter of the trigger signal is less than 24 ps, and the signal drift is controlled at about 3 ps after delay compensation, both meet the design requirements of HALF timing system.

Keywords

• half
• timing system
• arbitrary bucket filling
• mtca.4