A suite of diagnostics to validate and optimize the prototype ITER neutral beam injector

Pasqualotto, R.; Agostini, M.; Barbisan, M.; Brombin, M.; Cavazzana, R.; Croci, G.; Palma, M. Dalla; Delogu, R.; Muri, M. De; Muraro, A.; Peruzzo, S.; Pimazzoni, A.; Pomaro, N.; Rebaı̈, M.; Rizzolo, A.; Sartori, E.; Serianni, G.; Spagnolo, S.; Spolaore, M.; Tardocchi, M.; Zaniol, B.; Zaupa, M.

doi:10.1088/1748-0221/12/10/c10009

Cited by 30 publications

(16 citation statements)

References 25 publications

(25 reference statements)

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“…After a shutdown started at the end of November 2018, including the installation of the plasma grid mask, SPIDER operations resumed at mid-April 2019 and were devoted to the following activities: characterisation of the RF circuits; characterisation of the ion source; test of the extraction and accelerator power supplies; first characterisation of the SPIDER beam. As of 2019 most of SPIDER diagnostic systems 18 are operating: the list of source diagnostics 19 include source emission spectroscopy, surface and calorimetry thermocouples, Halpha detectors, visible cameras and electrical measurements at the various power supplies. The electrostatic sensors embedded in the plasma grid and in the bias plate 20 are under commissioning; the diagnostic systems more tightly related with caesium operation, like laser absorption spectroscopy 21 and cavity ring-down spectroscopy, will soon be installed and commissioned.…”

Section: Iib Source and Beam Characterisationmentioning

confidence: 99%

First operation in SPIDER and the path to complete MITICA

Serianni

Toigo

Bigi

et al. 2020

Review of Scientific Instruments

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The requirements of ITER neutral beam injectors (1 MeV, 40 A negative deuterium ion current for 1 h) have never been simultaneously attained; therefore, a dedicated Neutral Beam Test Facility (NBTF) was set up at Consorzio RFX (Padova, Italy). The NBTF includes two experiments: SPIDER (Source for the Production of Ions of Deuterium Extracted from Rf plasma), the full-scale prototype of the source of ITER injectors, with a 100 keV accelerator, to investigate and optimize the properties of the ion source; and MITICA, the full-scale prototype of the entire injector, devoted to the issues related to the accelerator, including voltage holding at low gas pressure. The present paper gives an account of the status of the procurements, of the timeline, and of the voltage holding tests and experiments for MITICA. As for SPIDER, the first year of operation is described, regarding the solution of some issues connected with the radiofrequency power, the source operation, and the characterization of the first negative ion beam.

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Section: Iib Source and Beam Characterisationmentioning

confidence: 99%

First operation in SPIDER and the path to complete MITICA

Serianni

Toigo

Bigi

et al. 2020

Review of Scientific Instruments

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“…SPIDER goal includes the validation of the design of ITER NBI support plants: cooling plant, removing thermal power (10MW) from power supplies, ion source, and beam dump [15]; central Instrumentation and Control systems (I&C) [16], providing conventional control (CODAS, Control and Data Acquisition System) [17], personnel protection (Central safety System) [18], investment protection (Central Interlock System, CIS) [19], managing also breakdowns in between the acceleration grids). SPIDER is equipped with a large set of diagnostic systems performing the measurements of the significant physics quantities [20]: thermocouples mounted on ion source, vacuum vessel and beam dump, flow and pressure sensors, electrostatic probes, emission and absorption spectroscopy, plasma light, visible and infrared cameras, beam tomography, neutron monitoring, cavity ring-down spectroscopy, STRIKE (Short-Time Retractable Instrumented Kalorimeter Experiment). Lines-of-sight (LoSs) observing the inside of the source through each of the drivers are used both for source emission spectroscopy and for total light emission [21].…”

Section: Spidermentioning

confidence: 99%

SPIDER in the roadmap of the ITER neutral beams

Serianni

Toigo

Bigi

et al. 2019

Fusion Engineering and Design

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To reach fusion conditions and control plasma configuration in ITER, a suitable combination of additional heating and current drive systems is necessary. Among them, two Neutral Beam Injectors (NBI) will provide 33MW hydrogen/deuterium particles electrostatically accelerated to 1MeV; efficient gas-cell neutralisation at such beam energy requires negative ions, obtained by caesium-catalysed surface conversion of atoms inside the ion source. As ITER NBI requirements have never been simultaneously attained, a Neutral Beam Test Facility (NBTF) was set up at Consorzio RFX (Italy), including two experiments. MITICA is the full-scale NBI prototype with 1MeV particle energy. SPIDER, with 100keV particle energy, aims at testing and optimising the full-scale ion source: extracted beam uniformity, negative ion current density (for one hour) and beam optics (beam divergence <7mrad; beam aiming direction within 2mrad). This paper outlines the worldwide effort towards the ITER NBI realisation: the main results of the ELISE facility (IPP-Garching, Germany), equipped with a half-size source, are described along with the status of MITICA; specific issues are investigated by small specific facilities and by joint experiments at QST and NIFS (Japan). The SPIDER experiment, just come into operation, will profit from strong modelling activities, to simulate and interpret experimental scenarios, and from advanced diagnostic instruments, providing thorough plasma and beam characterisation. Finally, the results of the first experiments in SPIDER are presented, aimed at a preliminary source plasma characterisation by plasma light detectors and plasma spectroscopy.

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“…Measuring the divergence of these ion beams is a challenge because of their high power density, large size, and overlapping beamlets. Diagnostics for doing so at full power and duration are by necessity spatially averaged measurements: either Beam Emission Spectroscopy (BES) observing a line of sight [13]; or beam dump calorimetry, where the beam footprint can be measured with a typical resolution of several centimetres at a position several metres from the grid system [14].…”

Section: Introductionmentioning

confidence: 99%