Characteristics of a 13.56 Mhz radiofrequency-driven multicusp ion source

• Main Authors: Boonyawan D., Chiraphatpimol N., Vilaithong T.
• Format: Article
• Language: English
• Published: 2014
• Online Access: http://www.scopus.com/inward/record.url?eid=2-s2.0-0036861411&partnerID=40&md5=5b9e283c5a87d4ff45d701a77047fd9f; http://cmuir.cmu.ac.th/handle/6653943832/5305
• Institution: Chiang Mai University

The characteristics of a radiofrequency (rf)-driven multicusp ion source are investigated. The ion source is an Nd-Fe-B magnetic multicusp type operated at 13.56 MHz with an internal quartz covered antenna. The source has been diagnosed by an rf-compensated Langmuir probe for uniformity, density and electron temperature. A retarding field energy analyser, and a multi-wire beam profile monitor and quadrupole magnet system have been used for beam energy spread and emittance measurements. Experiments were performed with argon gas and rf power up to 500 W. A plasma density of up to 1.5 × 1018 m-3 was obtained. The rms beam emittance is found to be about 32 ∓ 4 mm mrad, and the energy spread of the argon beam is around 3.1 ∓ 0.5 eV at 3 kV extraction. The rf coupling to the extracting voltage could be suppressed by a 1.2 mH rf choke, which results in the reduction of the axial energy spread in the extracted beam.