Conducting research and operator training while maintaining top-up reliability using the Advanced Photon Source linear accelerator

In recent years many changes have been made to the Advanced Photon Source (APS) linear accelerator (linac) to support multiple tasks. The primary purpose of the linac is to provide beam to fill the APS storage ring, which is done using thermionic cathode rf guns. At the same time we provide support for research projects, including a new facility that will be used for future operator training and testing of injector components. With each task requiring a different lattice and timing configuration, while at the same time using common rf systems, the complexity of operations has increased significantly with even greater demands being made on reliability and performance. In addition, personnel safety and equipment protection concerns have become more complex. We approached these challenges by developing three new subsystems: a highly automated linac operation using APS's Procedure Execution Manager (PEM) software; a new interlock system based on programmable logic controllers; and an automated S-band rf switching system. In this paper, we discuss how these developments have improved the flexibility and reliability of the APS linac, and how we intend to conduct operator training and test new injector components while maintaining storage ring injections.