An improved method of bunch-by-bunch beam position calculation in a heavy-ion synchrotron

The beam position monitor (BPM) system is a key element of the orbit correction system of a heavy-ion synchrotron. The bunch-by-bunch beam position calculation algorithm is one of the important parts of the BPM system, which determines the processing speed, accuracy and resolution of the beam position measurement. In this paper, a total least squares (TLS) algorithm based on an Exponentially Weighted Moving Average (EWMA) filter called EWMA TLS method is proposed, which applies to evaluate the beam position. A numerically simulated BPM signal, the signal from a test bench, as well as the real beam signal tested at the main Cooler Storage Ring of the Heavy Ion Research Facility in Lanzhou (HIRFL-CSRm) are analyzed using the new approach. The results demonstrate an improved accuracy of the position calculation of the bunches, and the method is much more robust against noise than previous methods, especially under the condition of a low signal-to-noise ratio (SNR), e.g. due to low beam intensities.