SLAC, Menlo Park, California, USA
BPM measurements in booster synchrotrons are often only critical during accelerator commissioning or when a problem occurs. As a result, many facilities do not make large investments in booster BPM signal processors; they either have very few BPMs and/or use older generation processors. The SPEAR3 booster BPM processor system, for instance, has operated since 1990 with commercial multiplexers to switch between BPM button signals into a single dated analog BPM processor that was developed at SLAC*. This system has reached its end-of-life so we are in the process of upgrading to modern multiplexers that feed a pair of turn-by-turn Libera SPARK-ERXR processors. This low-cost solution gives us the ability to arbitrarily multiplex between BPM signals during the energy ramp with modern BPM processors. The system can either measure 2 BPMs turn-by-turn in parallel during the entire energy ramp, or sequentially measure all BPMs (2 at a time) at different time slices within the ramp. Here we show measurements of the MiniCircuits switch we chose as well as our architecture for the upgrade.
*W. Lavender et al., "The SSRL injector beam position monitoring systems," 1991 IEEE Particle Accelerator Conference, San Francisco, CA, USA, 1991, pp. 1151-1153 vol.2, doi: 10.1109/PAC.1991.164563.
SLAC, Menlo Park, California, USA
I-Tech, Solkan, Slovenia
We are actively upgrading BPM processors in the SPEAR3 accelerator complex as several of the existing systems are reaching end-of-life. To consolidate the resources required for development and maintenance we have evaluated and installed several processors from the Libera SPARK hardware series. We found that two common deployment methods typically used with these modules, micro-SD card and network boot, are either hard to maintain or lack flexibility. Instead we have developed an automated method based on a network boot scheme where an external EPICS soft IOC manages the assignment of specific SPARK modules to physical BPMs in the accelerator. Each module queries the soft IOC at boot time to determine which BPM it is assigned to and then starts its IOC with the appropriate BPM prefix for the PV names. This deployment method allows for quick, seamless swapping of SPARK modules by machine operators or physicists. It addition, it allows us to bring additional modules online for testing, or to move modules to different locations with a different PV prefix for the new location. This method is applicable to other EPICS-enabled devices where the device hardware also hosts an IOC.