Optimization of the Entropy-Based Wavelet Method for Removing Strong RF and AC Interferences in a Charge Detection Linear Ion Trap Mass Spectrometer.

We developed an entropy-based wavelet method to effectively remove interference from strong radio frequency (RF) and auxiliary alternating current (AC) fields in a linear ion trap (LIT) mass spectrometer coupled to a charge sensing particle detector (CSPD). By optimizing the energy-to-Shannon entropy, we identified the optimal mother wavelet family and decomposition level and determined suitable threshold values based on the median of sub-band coefficients at each decomposition level. These thresholds were applied as rigid criteria across all decomposition levels to eliminate noise interferences and avoid the arbitrary choice of the threshold.