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Yun-Long(池云龙), PEI Shi-Lun(裴士伦) 1) , PEI Guo-Xi(裴国玺), WANG Shu-Hong(王书鸿), CAO Jian-She(曹 建社), HOU Mi(侯汨), LIU Wei-Bin(刘渭滨), ZHOU Zu-Sheng(周祖圣), ZHAO Feng-Li(赵风利), LIU Rong(刘熔), KONG Xiang-Cheng(孔祥成), ZHAO Jing-Xia(赵敬霞), DENG Chang-Dong(邓昌东), SONG Hong(宋洪), LIU Jin-Tong(刘晋通), DAI Xu-Wen(戴旭文), YUE Jun-Hui(岳军会), YANG Qi(杨奇), HE Da-Yong(何大勇), HE Xiang(贺 祥), LE Qi(乐琪), LI Xiao-Ping(李小平), WANG Lin(汪林), WANG Xiang-Jian(王湘鉴), MA Hui-Zhou(麻惠洲), ZHAO Xiao-Yan(赵晓岩), SUI Yan-Feng(随艳峰), GUO Hai-Sheng(郭海生), MA Chuang-Xin(马创新), ZHAO Jian-Bing(赵建兵), CHEN Peng(陈鹏)

To establish a nuclear resonant scattering beamline at the High Energy Photon Source (HEPS), it is essential to develop tools for detection and cleaning of parasitic bunches, for meeting the stringent demands on bunch purity. To this end, a novel time-correlated singlephoton counting system was implemented at the electron storage ring of the Beijing Electron-Positron Collider II (BEPCII). The purity deterioration process over a weeklong operation was recorded by the system. In this study, the mechanism of impurity growth was analyzed by numerical methods and validated on measurements. The agreement between the experimental results and the calculation was fairly good. Two main sources of parasitic bunches, pre-accelerators and the Touschek scattering were confirmed. A bunch-cleaning technique, based on a sinusoidal signal mixed with a pseudo-square wave, was also developed and implemented, and its capability to improve the bunch purity to the level of 10 -7 was experimentally demonstrated. We present the experimental setup, principle, and measurement results of a system for detection and cleaning of parasitic bunches.