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Development of a Compact Electron Beam Ion Source Cooled with Liquid Nitrogen

1989; Institute of Physics; Volume: 28; Issue: 6R Linguagem: Inglês

10.1143/jjap.28.1124

1347-4065

K. Okuno,

Plasma Diagnostics and Applications

A small-sized EBIS type ion source (mini-EBIS) for production of highly charged ions has been developed. The whole system, namely, the electron gun, ion drift tube, electron collector, ion extraction lens and liquid nitrogen reservoir containing solenoid coil is housed in a vacuum envelope, 150 mmφ in diameter and 500 mm in length. The idea of cooling the solenoid to 77 K has proved very effective to miniaturize the solenoid and its power supply. Moreover, the wall of the liquid nitrogen reservoir exhibits a cryogenic pumping function at the ionization region. In the D C ion extraction mode with an electron current of 15 mA at 2 keV, beam intensities obtained for C 6+ , N 7+ , O 8+ , Ne 9+ and Ar 16+ ions are at least 5×10 4 , 3×10 4 , 1×10 4 , 5×10 3 and 3×10 3 counts per second, respectively.