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TY - UNPB AU - He, J. AU - Yue, J.H. ED - Tavares, Daniel ED - Picoreti, Renan ED - Bruno, Gustavo ED - Marques, Sergio ED - Schaa, Volker R.W. TI - Bunch Purity Measurement and Improvement J2 - Proc. of IBIC2020, Santos, Brazil, 14-18 September 2020 CY - Santos, Brazil T2 - International Beam Instrumentation Conference T3 - 9 LA - english AB - A signal electron level purity is mandatory for a nuclear resonant scattering experiment. For the establishing such kind of beamlines on High Energy Photon Source (HEPS), a new time-correlated single photon counting system has been implemented on the storage ring of Beijing Electron-Positron Collider II (BEPCII), which is used to monitor the purity. The system could track the purity deterioration process. The possible reason of impurity growth is analysed, the measurement results confirmed that Touschek scattering and pre-accelerators of the storage ring are the main mechanisms of impurity growth. A bunch cleaning technique based on a sinusoidal signal mixed a pseudo-square wave has been verified which could improve the purity to the level of 10⁻⁷. This paper mainly describes the experiment details and measurement results of purity measurement and improvement. PB - JACoW Publishing CP - Geneva, Switzerland ER -