Speaker
Description
Reliable communication and control of distributed electronics is essential for safe and efficient accelerator operations at CERN. This work presents the first application of new C++ library designed to manage Beam Loss Monitoring (BLM) acquisition electronics using Low-Power Gigabit Transceivers (LpGBT). This library enables real-time communication between tunnel-based and surface-level processing subsystems, delivering high performance and robust reliability. It supports redundant optical links, custom medium access, internal and external LpGBT control, and I²C links. Although LpGBT is widely deployed in LHC experiments, this marks the first integration in CERN’s Accelerator Technologies sector, offering enhanced control capabilities via radiation-tolerant, bidirectional communication.
Summary (500 words)
Introduction
The Beam Loss Monitoring (BLM) system is critical to the optimisation and safe operation of the Super Proton Synchrotron (SPS) at CERN. As part of ongoing modernisation efforts, there is an increasing need for robust and efficient control of radiation-hardened acquisition electronics located as close as possible to the beamline. This requires reliable bidirectional communication over LpGBT links and integration within CERN’s accelerator control infrastructure.
Motivation and Background
In the LHC experiments, LpGBT control mechanisms often rely on Python-based libraries while adequate and functional for that environment, these implementations are suboptimal for critical and time-sensitive tasks operating in front-end computers. To meet the real-time performance and reliability requirements of accelerator controls, we present a newly developed C++ control library, inspired by the Python library provided by CERN’s EP department, and designed to interface with BLM acquisition electronics via LpGBT links. This development represents the first application of such a solution within CERN’s Accelerator Technologies sector and is fully compatible with CERN’s Front-End Software Architecture (FESA) framework.
LpGBT Control Library
The C++ library provides low-latency, high-reliability communication with remote electronics. It supports multiple LpGBT link configurations, including redundant link management and flexible medium access options such as internal and external control (IC/EC) paths and I²C slave buses. The use of C++ ensures deterministic execution and improved performance over Python-based implementations, making it suitable for real-time applications. Full compatibility with FESA allows seamless integration with existing supervisory and control infrastructure.
API and System Architecture
A generic application programming interface (API) has been developed to facilitate interaction between the LpGBT control library and the software framework. The API provides a structured mechanism for managing link configurations and hardware interfaces while supporting fault tolerance through link redundancy. The control architecture has been designed with modularity and maintainability in mind, as illustrated in the accompanying system diagram.
Deployment and Outlook
Deployment of the library is scheduled for the upcoming Long Shutdown 3 (LS3) as part of the BLM system upgrade. Validation and performance testing are ongoing. Thanks to its modular design and general-purpose interface, the library has potential applications beyond the BLM system and could serve as foundation for broader adoption in other beam instrumentation systems and other accelerator subsystems.
Conclusion
This work focuses on the development of a high-performance, LpGBT-based control solution for tunnel electronics and with full integration into the FESA framework. The approach aims to deliver a scalable, reliable, and real-time-capable solution for future accelerator control applications at CERN. Preliminary results are promising, with further testing and validation planned ahead of system deployment.
