Low frequency response characteristics of B-dot monitor in cavity

The frequency response of B-dot monitors fielded in the cavity of magnetically-insulated transmission lines is analyzed. The equivalent sensitivity of B-dot monitors in the cavity could be increased at low frequencies. The B-dot monitor behaves approximately as if its signal were transmitted though a high-pass RC filter with negative RC time constant, and the lower frequency components are amplified. The experiments were carried on at different equivalent frequencies. It shows that both the characteristic flux-penetration time and the mutual inductance between the main circuit and the B-dot monitor are different while the frequency of the test signal is changed. The equivalent bandwidth of calibration waveform should approach the real waveform to get the exact correcting coefficients.