Commissioning of helium injector for coupled radio frequency quadrupole and separated function radio frequency quadrupole accelerator

• Published in: Review of scientific instruments 2014-02, Vol.85 (2), p.02A712-02A712
• Main Authors: Peng, Shixiang, Chen, Jia, Ren, Haitao, Zhao, Jie, Xu, Yuan, Zhang, Tao, Zhang, Ailing, Xia, Wenlong, Gao, Shuli, Wang, Zhi, Luo, Yuting, Guo, Zhiyu, Chen, Jia'er
• Format: Article
• Language: English
• Subjects: ACCELERATORS; BEAM TRANSPORT; COMMISSIONING; ECR ION SOURCES; GHZ RANGE 01-100; PARTICLE ACCELERATORS; PERMANENT MAGNETS; RADIOWAVE RADIATION
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.4828375

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%.