Development of versatile multiaperture negative ion sources

Cavenago, M.; Serianni, G.; Antoni, V.; Bigi, M.; Muri, M. De; Pasqualotto, R.; Recchia, M.; Veltri, P.; Agostinetti, P.; Barbisan, M.; Baseggio, L.; Cervaro, V.; Cazzador, M.; Agostini, F. Degli; Franchin, L.; Kulevoy, T. V.; Laterza, B.; Mimo, A.; Minarello, A.; Petrenko, S. V.; Ravarotto, D.; Rossetto, F.; Sattin, Marta; Zaniol, B.; Zucchetti, S.

doi:10.1063/1.4916448

Cited by 6 publications

(1 citation statement)

References 30 publications

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“…Optimizing the production of H -/Dion beams is a crucial task for the operation and the efficiency of future fusion reactors. To contribute to this purpose Consorzio RFX and INFN-LNL have designed, built and operated the NIO1 (Negative Ion Optimization 1) experiment [1][2][3]. NIO1 hosts a small (10 cm diameter x 21 cm length) and flexible negative ion source, in which a plasma is created thanks to the RF power (max.…”

Section: Introductionmentioning

confidence: 99%

Electron density and temperature in NIO1 RF source operated in oxygen and argon

Barbisan

Zaniol

Cavenago³

et al. 2017

AIP Conference Proceedings

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The NIO1 experiment, built and operated at Consorzio RFX, hosts an RF negative ion source, from which it is possible to produce a beam of maximum 130 mA in Hions, accelerated up to 60 kV. For the preliminary tests of the extraction system the source has been operated in oxygen, whose high electronegativity allows to reach useful levels of extracted beam current. The efficiency of negative ions extraction is strongly influenced by the electron density and temperature close to the Plasma Grid, i.e. the grid of the acceleration system which faces the source. To support the tests, these parameters have been measured by means of the Optical Emission Spectroscopy diagnostic. This technique has involved the use of an oxygen-argon mixture to produce the plasma in the source. The intensities of specific Ar I and Ar II lines have been measured along lines of sight close to the Plasma Grid, and have been interpreted with the ADAS package to get the desired information. This work will describe the diagnostic hardware, the analysis method and the measured values of electron density and temperature, as function of the main source parameters (RF power, pressure, bias voltage and magnetic filter field). The main results show that not only electron density but also electron temperature increase with RF power; both decrease with increasing magnetic filter field. Variations of source pressure and plasma grid bias voltage appear to affect only electron temperature and electron density, respectively.

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Section: Introductionmentioning

confidence: 99%

Electron density and temperature in NIO1 RF source operated in oxygen and argon

Barbisan

Zaniol

Cavenago³

et al. 2017

AIP Conference Proceedings

Self Cite

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First experiments with the negative ion source NIO1

Cavenago

Serianni²,

Muri

et al. 2015

Review of Scientific Instruments

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Neutral Beam Injectors (NBIs), which need to be strongly optimized in the perspective of DEMO reactor, request a thorough understanding of the negative ion source used and of the multi-beamlet optics. A relatively compact radio frequency (rf) ion source, named NIO1 (Negative Ion Optimization 1), with 9 beam apertures for a total H(-) current of 130 mA, 60 kV acceleration voltage, was installed at Consorzio RFX, including a high voltage deck and an X-ray shield, to provide a test bench for source optimizations for activities in support to the ITER NBI test facility. NIO1 status and plasma experiments both with air and with hydrogen as filling gas are described. Transition from a weak plasma to an inductively coupled plasma is clearly evident for the former gas and may be triggered by rising the rf power (over 0.5 kW) at low pressure (equal or below 2 Pa). Transition in hydrogen plasma requires more rf power (over 1.5 kW).

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The characterization and optimization of NIO1 ion source extraction aperture using a 3D particle-in-cell code

Taccogna

Minelli

Cavenago

et al. 2015

Review of Scientific Instruments

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The geometry of a single aperture in the extraction grid plays a relevant role for the optimization of negative ion transport and extraction probability in a hybrid negative ion source. For this reason, a three-dimensional particle-in-cell/Monte Carlo collision model of the extraction region around the single aperture including part of the source and part of the acceleration (up to the extraction grid (EG) middle) regions has been developed for the new aperture design prepared for negative ion optimization 1 source. Results have shown that the dimension of the flat and chamfered parts and the slope of the latter in front of the source region maximize the product of production rate and extraction probability (allowing the best EG field penetration) of surface-produced negative ions. The negative ion density in the plane yz has been reported.

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Development of versatile multiaperture negative ion sources

Cited by 6 publications

References 30 publications

Electron density and temperature in NIO1 RF source operated in oxygen and argon

Electron density and temperature in NIO1 RF source operated in oxygen and argon

First experiments with the negative ion source NIO1

The characterization and optimization of NIO1 ion source extraction aperture using a 3D particle-in-cell code

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