Real-time monitoring of longitudinal beam quality across the CERN accelerator complex

Abstract

Acquiring and processing longitudinal beam profiles in the CERN injector complex is essential for maintaining high beam quality for both the Large Hadron Collider and fixed-target experiments. This paper describes a new and common framework across the injector chain to continuously monitor longitudinal profiles, based on digitizers connected to wall current monitors. A new software class has been developed using the Front-End Software Architecture framework to improve real-time monitoring of longitudinal beam quality along the whole beam production cycle. The new implementation supports efficient data acquisition with highly flexible configuration options, including per-profile and per-cycle settings management. This acquisition class reduces data transfer time from the hardware and enables simultaneous beam monitoring and optimization for multiple users across the CERN accelerator complex. Beyond the raw data acquisition layer, real-time processing analyses have been developed on the Unified Controls Acquisition and Processing platform to perform bunch length, bunch-by-bunch intensity, and bunch spacing measurements, and tomographic reconstruction of the longitudinal phase space to provide key longitudinal parameters such as momentum spread and emittance. This new monitoring framework paves the way for preparing and executing the filling of the LHC in an automated manner and for optimizing fixed-target cycles for physics users.