Operation of RF driven negative ion source in a pure-hydrogen mode

Abstract

Abstract. The production of negative hydrogen ions in the radio-frequency driven long-pulsed source with external antenna is studied. RF drivers with various geometry of external antenna, Faraday shield and magnets at the rear flange were examined. H-beam extraction through the single emission aperture was performed in the source pure-hydrogen mode with no external seed of alkali additives. H-beam with ion emission current density up to 5 mA/cm 2 and energy up to 75 keV was regularly obtained in the 1 s pulses of the pure-hydrogen mode. The regular temporal increase of H-ion production due to deposition of impurities on the plasma grid surface was recorded. The H-emission current density increased up to 9 mA/cm 2 in this case.

Negative ion production in the RF multiaperture surface-plasma source

“…The ratio of H-beam current to the current of co-extracted electrons had the value I -/I e -1. The H-current, obtained in the hydrogen-cesium mode is about 3 times higher, than that in the pure-hydrogen mode [3], while the extracted current, recorded in the hydrogen-cesium mode was about 2 times lower, than the extracted current, obtained in the purehydrogen mode.…”

“…A Faraday screen (FS) is installed inside the ceramic cylinder to protect it from the erosion by plasma. Plasma production by the RF drivers with various configurations of the magnet, RF antenna and Faraday screen were studied at the separate test stand [3]. Drivers with no FS and with 0.5 mm thick molybdenum FS were used in the presented NI extraction experiments.…”

“…The apertures at the PG corners were kept plugged to prevent cesium bleeding to the extraction gap. Second, the magnet configuration at the RF driver back wall was changed to the checkerboard one to enhance the efficiency of RF power absorption [3]. The initial tests were done with no Faraday Screen installed in the RF driver.…”

“…This paper presents the results on H-beam production in the hydrogen-cesium mode. The results on beam production in the hydrogen mode with no cesium are discussed in the accompanying paper [3].…”

Πειραματική Μελέτη Της Παραγωγής Αρνητικών Ιόντων Η- Από Πλάσμα Κυκλοτρονικού Συντονισμού Ηλεκτρονίων

“…Δπηπξφζζεηα, ε ιεηηνπξγία ηεο πεγήο παξνπζηάδεη κεγάιε επαηζζεζία ζηηο δηαθπκάλζεηο θαη ηε κεηαθνξά ηνπ θαηζίνπ, ην νπνίν κπνξεί αθφκα θαη λα εηζρσξήζεη ζην ζχζηεκα εμαγσγήο θαη λα νδεγήζεη ζε ππν-νλνκαζηηθή ιεηηνπξγία ή αθφκα θαη αζηνρία. πλεπψο, ε παξαγσγή φγθνπ, έρνληαο ην πιενλέθηεκα ηεο ιεηηνπξγίαο ρσξίο θαίζην, απνηειεί αθφκα αληηθείκελν έξεπλαο κε πεγέο πνπ βαζίδνληαη ζε εθθελψζεηο ξαδηνζπρλνηήησλ [47][48][49], θπθινηξνληθνχ ζπληνληζκνχ ειεθηξνλίσλ [31,[49][50][51], ειηθνεηδψλ θπκάησλ [33] ή αθφκα θαη λεκαηίσλ Κεθάιαην 1. Δηζαγσγή -18 -ππξαθηψζεσο [52,53].…”