Research of Baseline Shift of Beam Current Transformer

The beam current transformer (BCT) shows bandpass characteristic in the frequency domain, and the low-frequency cut-off character is the reason of baseline shift. In this paper, the analysis of the baseline shift for single bunch and continuous bunches was presented using high pass filter model. Two methods as baseline manipulation and primary harmonic algorithm were used to do baseline restoration. And the measurement relative error of the high frequency continuous bunches is reduced from 20% to less than 3%.