Design and analyses of a one-dimensional CFC calorimeter for SPIDER beam characterisation

Rizzolo, A.; Palma, M. Dalla; Muri, M. De; Serianni, G.

doi:10.1016/j.fusengdes.2010.09.003

Cited by 33 publications

(16 citation statements)

References 10 publications

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“…These effects are generally considered detrimental for the ITER NBI, as they are expected to cause higher heat loads on the ITER NBI neutralizer and decrease the overall beam quality (in terms of aiming and divergence). Hence the ion deflection should be considered and minimized also for the SPIDER device, where it will be possible to precisely investigate the beamlet footprint using an instrumented calorimeter relatively close to the accelerator exit [13]. A design optimization process has been carried out aiming at compensating these effects [24].…”

Section: Multi Beamlet Optics Analysesmentioning

confidence: 99%

Physics and engineering design of the accelerator and electron dump for SPIDER

et al. 2011

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The ITER Neutral Beam Test Facility (PRIMA) is planned to be built at Consorzio RFX (Padova, Italy). PRIMA includes two experimental devices: a full size ion source with low voltage extraction called SPIDER and a full size neutral beam injector at full beam power called MITICA. SPIDER is the first experimental device to be built and operated, aiming at testing the extraction of a negative ion beam (made of H − and in a later stage D − ions) from an ITER size ion source. The main requirements of this experiment are a H − / D − extracted current density larger than 355 / 285 A m −2 , an energy of 100 keV and a pulse duration of up to 3600 s. Several analytical and numerical codes have been used for the design optimization process, some of which are commercial codes, while some others were developed ad hoc. The codes are used to simulate the electrical fields (SLACCAD, BYPO, OPERA), the magnetic fields (OPERA, ANSYS, COMSOL, PERMAG), the beam aiming (OPERA, IRES), the pressure inside the accelerator (CONDUCT, STRIP), the stripping reactions and transmitted/dumped power (EAMCC), the operating temperature, stress and deformations (ALIGN, ANSYS) and the heat loads on the electron dump (EDAC, BACKSCAT). An integrated approach, taking into consideration at the same time physics and engineering aspects, has been adopted all along the design process. Particular care has been taken in investigating the many interactions between physics and engineering aspects of the experiment. According to the "robust design" philosophy, a comprehensive set of sensitivity analyses was performed, in order to investigate the influence of the design choices to the most relevant operating parameters. The design of the SPIDER accelerator, here described, has been developed in order to satisfy with reasonable margin all the requirements given by ITER, from the physics and engineering points of view. In particular, a new approach to the compensation of unwanted beam deflections inside the accelerator and a new concept for the Electron Dump have been introduced.

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Section: Multi Beamlet Optics Analysesmentioning

confidence: 99%

Physics and engineering design of the accelerator and electron dump for SPIDER

et al. 2011

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“…We propose to install the RFEA also in SPIDER; in that case, the hydrogen pressure in the vessel during operation is expected to be 0.05 Pa [20], high enough for a relatively dense secondary plasma to develop. The RFEA could be used in synergy with the instrumented calorimeter STRIKE [21], which can measure the drained current but not distinguish between beam ions and secondary charges such as plasma electrons or ions.…”

Section: Discussionmentioning

confidence: 99%

Development of an energy analyzer as diagnostic of beam-generated plasma in negative ion beam systems

Sartori

Carozzi

Veltri

et al. 2017

AIP Conference Proceedings

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“…The material employed for the target has been graphite or a special carbon-fibre-carbon composite exhibiting very good one-directional propagation capabilities. For SPIDER the instrumented calorimeter short time retractable instrumented kalorimeter experiment (STRIKE) was designed and is under construction for investigating beam divergence and halo in SPIDER and for measuring the uniformity of the negative ion beam [121]. The expected spatial resolution is around 2 mm.…”

Section: Measurement Of Beam Energy Flux By Direct Interceptionmentioning

confidence: 99%

Neutralisation and transport of negative ion beams: physics and diagnostics

Serianni¹,

Agostinetti²,

Agostini³

et al. 2017

New J. Phys.

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Neutral beam injection is one of the most important methods of plasma heating in thermonuclear fusion experiments, allowing the attainment of fusion conditions as well as driving the plasma current. Neutral beams are generally produced by electrostatically accelerating ions, which are neutralised before injection into the magnetised plasma. At the particle energy required for the most advanced thermonuclear devices and particularly for ITER, neutralisation of positive ions is very inefficient so that negative ions are used. The present paper is devoted to the description of the phenomena occurring when a high-power multi-ampere negative ion beam travels from the beam source towards the plasma. Simulation of the trajectory of the beam and of its features requires various numerical codes, which must take into account all relevant phenomena. The leitmotiv is represented by the interaction of the beam with the background gas. The main outcome is the partial neutralisation of the beam particles, but ionisation of the background gas also occurs, with several physical and technological consequences. Diagnostic methods capable of investigating the beam properties and of assessing the relevance of the various phenomena will be discussed. Examples will be given regarding the measurements collected in the small flexible NIO1 source and regarding the expected results of the prototype of the neutral beam injectors for ITER. The tight connection between measurements and simulations in view of the operation of the beam is highlighted. operating in the existing tokamaks. Consequently, PRIMA, the ITER Neutral Beam Test Facility [2], was set up to constitute a test-bed, where the solutions to all the issues related to the achievement of full performances in the heating NBI system for ITER are going to be addressed and optimised, particularly regarding critical aspects like density and uniformity of the extracted negative ion current, high voltage holding and heat loads on the components [3]. Megavolt ITER Injector Concept Advancement (MITICA) is the full-scale prototype of the ITER NBIs [4]; it includes an RF-driven plasma source for the production of negative ions and should operate at a pressure as low as 0.3 Pa in hydrogen or deuterium gasses. The negative ions are produced on the surface of the grid (Plasma Grid, PG) that closes the plasma region; their production is enhanced thanks to a thin caesium layer continuously deposited over the PG by evaporation. Negative ions are extracted through the 1280 apertures in the PG by application of a suitable positive voltage to the extraction grid (EG), located just downstream of the PG. The RF plasma source operates at an applied electric potential of about −1 MV. Five additional acceleration grids (AG1, AG2, AG3, AG4, GG), at intermediate electric potential increasing by 200 kV steps, are located downstream with respect to the EG, thus constituting a 5-stage electrostatic accelerator. The resulting negative ion beam at 1 MeV, after passing through a gas cell neutraliser and an electro...

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Design and analyses of a one-dimensional CFC calorimeter for SPIDER beam characterisation

Cited by 33 publications

References 10 publications

Physics and engineering design of the accelerator and electron dump for SPIDER

Physics and engineering design of the accelerator and electron dump for SPIDER

Development of an energy analyzer as diagnostic of beam-generated plasma in negative ion beam systems

Neutralisation and transport of negative ion beams: physics and diagnostics

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