Fourier denoising analysis in Bρ-defined isochronous mass spectrometry

B ρ - defined isochronous mass spectrometry (B ρ - IMS) based on heavy ion storage rings is a newly developed technique for precise measurement of short-lived nuclide mass. By installing two time-of-flight detectors on the straight section of the storage ring to measure the orbital time and velocity of stored ions, high-precision quality measurement can be achieved. The electromagnetic noise of the detection system is one of the main sources of uncertainty in the quality value of B ρ - IMS. In the development process of B ρ - IMS, digital Fourier denoising analysis was applied to process the full waveform timing signal sampled by a digital oscilloscope. In the analysis, multiple periodic electrical components were unexpectedly discovered in the timing signal, with frequencies that are exactly integer multiples of the oscilloscope sampling rate. Through this analysis, for nuclides with atomic numbers Z ≥ 15, the systematic bias in the re determined mass values is eliminated at the 1 σ confidence level; At the same time, the accuracy of the measured velocity and ion mass has also been improved to the same extent, with an increase of 7% to 20%. Further research has found that the amplitude of these periodic components is related to the voltage sampling range of the oscilloscope and exhibits quasi periodic variations at different times of the day. Given the widespread application of digital oscilloscopes, this discovery has reference significance for experiments using similar electronic devices.