Improvements of the versatile multiaperture negative ion source NIO1

Cavenago, M.; Serianni, G.; Muri, M. De; Veltri, P.; Antoni, V.; Baltador, C.; Barbisan, M.; Brombin, M.; Galatà, A.; Ippolito, N.; Kulevoy, T. V.; Pasqualotto, R.; Petrenko, S. V.; Pimazzoni, A.; Recchia, M.; Sartori, E.; Taccogna, F.; Variale, V.; Zaniol, B.; Barbato, P.; Baseggio, L.; Cervaro, V.; Fasolo, D.; Franchin, L.; Ghiraldelli, R.; Laterza, B.; Maniero, M.; Martini, D.; Migliorato, Luisa; Minarello, A.; Molon, F.; Moro, G.; Patton, T.; Ravarotto, D.; Rizzieri, R.; Rizzolo, A.; Sattin, M.; Stivanello, F.; Zucchetti, S.

doi:10.1063/1.4995727

Cited by 10 publications

(6 citation statements)

References 26 publications

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“…NIO1 (Negative Ion Optimization phase 1) is a radiofrequency Hion source, built and operated by Consorzio RFX and INFN-LNL, with the aim of studying the production and acceleration of negative ions, to address present and future issues and needs of negative ions sources for neutral beam injectors in fusion reactor (DEMO in particular) [ [1]- [4]]. The NIO1 source is designed to be compact and flexible for the test of new concepts, components and instrumentation.…”

Section: Introductionmentioning

confidence: 99%

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Cs Evaporation in a Negative Ion Source and Cs Cleaning Tests by Plasma Sputtering

Barbisan

Delogu

Pimazzoni

et al. 2022

IEEE Trans. Plasma Sci.

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The compact radio frequency negative ion source NIO1 (Negative Ion Optimization phase 1) has been designed, built and operated by Consorzio RFX and INFN-LNL in order to study and optimize the production and acceleration of Hions in continuous operation. In 2020 Cs was evaporated in the source to increase the total extracted ion current. After an initial reduction of extracted electron to ion ratio and subsequently an increase of extracted negative ion current, the source performances progressively worsened, because of the excessive amount of Cs evaporated in the source; the extracted electron to ion ratio increased from below 1 to more than 10, while ion current density reduced from max. 67 A/m 2 ion current to not more than 30 A/m 2 ). The paper presents the experimental observations collected during Cs evaporation (reduction of plasma light, Cs emission and Hβ/Hγ ratio, etc.) that can help stopping the process before an excessive amount of Cs is introduced in the source. The paper also reports the cleaning techniques tested to remove the Cs excess by the action of hydrogen or argon plasmas; while argon was predictably more effective in surface sputtering, a 3 h Ar plasma treatment was not sufficient to recover from overcesiation.

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Section: Introductionmentioning

confidence: 99%

“…2 and 10 of ref. [1]), and the source body. During the experimental campaign, which is object of this paper, the two bias plates were electrically connected outside vacuum and will be hereafter referred as a single bias plate (BP).…”

Section: Introductionmentioning

confidence: 99%

Cs Evaporation in a Negative Ion Source and Cs Cleaning Tests by Plasma Sputtering

Barbisan

Delogu

Pimazzoni

et al. 2022

IEEE Trans. Plasma Sci.

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“…The test of such a system in the small negative ion beam system NIO1 the topic of this paper, which describes the feasibility study for a beam driven plasma neutralizer test in a small ion source such as NIO1 [16,17]. Due to its versatility NIO ion source is considered for testing other advanced concept for NBIs [18].…”

Section: Neutralization Efficiency and Beam-driven Plasma Neutralizersmentioning

confidence: 99%

Preliminary studies for a beam-generated plasma neutralizer test in NIO1

Sartori

Veltri

Balbinot

et al. 2017

AIP Conference Proceedings

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“…The study presented in this paper will show the main measurements obtained by the OES diagnostic on NIO1, during the experimental campaigns in which hydrogen was replaced by a mixture of oxygen (90%) and argon (10 %) [6]. This mixture was preferred to hydrogen to perform the tests for the acceleration system; oxygen is indeed more electronegative than hydrogen, therefore it is possible to extract a higher current of negative ions from the source.…”

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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Improvements of the versatile multiaperture negative ion source NIO1

Cited by 10 publications

References 26 publications

Cs Evaporation in a Negative Ion Source and Cs Cleaning Tests by Plasma Sputtering

Cs Evaporation in a Negative Ion Source and Cs Cleaning Tests by Plasma Sputtering

Preliminary studies for a beam-generated plasma neutralizer test in NIO1

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

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