CERN, Geneva
The BBQ tune (Q) and chromaticity (Q') diagnostic systems played a crucial role during LHC commissioning, both in establishing circulating beam and for the first ramps. Early on, they allowed identification of issues such as the residual tune stability, beam spectrum interferences and beam-beam effects – all of which may impact beam life times and are therefore being addressed in view of nominal LHC operation. This contribution discusses the initial beam stability in relation to the achieved instrumentation sensitivity, corresponding tune frequency and chromaticity resolution.
CERN, Geneva
The LHC Beam Loss Monitoring (BLM) system is one of the most complex instrumentation systems deployed in the LHC. In addition to protecting the collider, the system also needs to provide a means of diagnosing machine faults and deliver feedback of losses to the control room as well as to several systems for their setup and analysis. It has to transmit and process signals from over 4,000 monitors, and has nearly 3 million configurable parameters. In a system of such complexity, firmware reliability is a critical issue. The integrity of the signal chain of the LHC BLM system and its ability to correctly detect unwanted scenarios and thus provide the required protection level must be ensured. In order to analyze the reliability and functionality, a test bench has been developed that emulates different types of loss signals and monitors the performance and response of the FPGA-based data analysis firmware. This paper will report on the numerous tests that have been performed and on how the results are used to quantify the reliability of the system.