Title : " A 13.56 Mhz Multicusp Ion Source for High Intensing Ar Beam"

Researcher : Deerawan Boonyawan

Office of Researcher : PHYSICS


A 13.56 MHz radio frequency (rf) inductively coupled multicusp ion source has been developed for producing an intense argon ion beam with current density in excess of 30 mA cm-2 . The source chamber is a 10 cm diameter aluminum cylinder surrounded by 20 rows of 3.5 kG Sm-Co5 magnets which form a longtitudinal line-cusp field configuration. The rf antenna coil, placed inside the source chamber, is made of a braided wire threaded through a 2 turns pyrex tube 6 cm in diameter to prevent electrical leakage and ion sputtering. A 10:1 turns-ratio matching transformer is used to match the 50 output impedance of the rf generator to the impedance of the plasma load.

Preliminary measurements were carried out with single and 4-hole aperture using argon gas. For a single hole extraction with pressure at 5 mTorr and rf power at 500 W, the ion current density was 27 mAcm-2 . With the same operating condition, the current density was about 25 mAcm-2 for a 4-hole extraction system.

Presented at The 8th International Conference on Ion Sources (ICIS'99X, Kyoto, Japan, 6-10 September, 1999.