Cao, S.S. Chen, J. Leng, Y.B. Yuan, R.X. JACoW Geneva, Switzerland 978-3-95450-192-2 10.18429/JACoW-IBIC2017-TUPCC18 English 193-195 TUPCC18 ion cavity FEL pick-up experiment Contribution to a conference proceedings 2018 2018-03 https://doi.org/10.18429/JACoW-IBIC2017-TUPCC18 http://jacow.org/ibic2017/papers/tupcc18.pdf Shanghai Soft X-ray Free Electron Laser (SXFEL) is a fourth-generation light source which could provide coherent X-rays for various scientific researches. One of the key issues of its operation is the measurement of bunch arrival time which is important for the synchronization of a bunch and seeded laser. The measurement utilized a newly designed beam arrival time monitor (BAM) which contains two cavities at a different frequency. Thus a new way, dual-cavities mixing method, is applied in this experiment to evaluate the beam arrival time resolution. In this paper, we presented the scheme and different measured resolution of various measurement methods and evaluated the stability of the new monitor.