2013•Review of Scientific InstrumentsRequires access
Commissioning of helium injector for coupled radio frequency quadrupole and separated function radio frequency quadrupole accelerator
Shixiang Peng, Jia Chen, Haitao Ren, Jie Zhao, Yuan Xu, Tao Zhang, Ailin Zhang, Wenlong Xia, Shuli Gao, Zhi Wang, Yuting Luo, Zhiyu Guo, Jiaer Chen
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Abstract
A project to study a new type of acceleration structure has been launched at Peking University, in which a traditional radio frequency quadrupole (RFQ) and a separated function radio frequency quadrupole are coupled in one cavity to accelerate the He+ beam. A helium injector for this project is developed. The injector consists of a 2.45 GHz permanent magnet electron cyclotron resonance ion source and a 1.16 m long low energy beam transport (LEBT). The commissioning of this injector was carried out and an onsite test was held in June 2013. A 14 mA He+ beam with the energy of 30 keV has been delivered to the end of the LEBT, where a diaphragm with the diameter of 7 mm is located. The position of the diaphragm corresponds to the entrance of the RFQ electrodes. The beam emittance and fraction were measured after the 7 mm diaphragm. Its rms emittance is about 0.14 π mm mrad and the fraction of He+ is about 99%.