Overview of neutron and confined escaping alpha diagnostics planned for ITER

Sasao, M.; Krasilnikov, A. V.; Nishitani, T.; Batistoni, P.; Zaveryaev, V.S.; Kaschuck, Yu. A.; Popovichev, S.; Iguchi, Tetsuo; Jarvis, O.N.; Källne, J.; Fiore, C. L.; Roquemore, L.; Heidbrink, W. W.; Donné, A. J. H.; Costley, A. E.; Walker, Chris

doi:10.1088/0741-3335/46/7/s08

Cited by 39 publications

(86 citation statements)

References 20 publications

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“…It is well known that the self-heating of a DT plasma by alpha-particles is the key to realize a selfsustainable thermonuclear plasma. The alpha-diagnostics for a fusion reactor is reviewed in some recent papers [1,2]. As described in the review papers, it is still difficult to measure the distributions of confined and escaping alphaparticles and several proposals to solve such difficulties and related problems are now under examination [2].…”

Section: Inroductionmentioning

confidence: 99%

“…The alpha-diagnostics for a fusion reactor is reviewed in some recent papers [1,2]. As described in the review papers, it is still difficult to measure the distributions of confined and escaping alphaparticles and several proposals to solve such difficulties and related problems are now under examination [2].We find difficulty in using normal alpha-particle detectors such as a semiconductor detector and a scintillation detector under the condition of high temperature. Ceramic material is fundamentally tough against the effects of highenergy particles, high temperature, high voltage and other severe conditions.…”

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confidence: 99%

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Development of a Simple and Tough Alpha-Particle Detector Used at High Temperature

Iida

Sato

Kato

et al. 2007

Plasma and Fusion Research

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Several ceramic detectors were made by use of the insulation layer formed on two types of substrate, i.e. aluminum and silicon. Each detector was irradiated with alpha-rays from an Am-241 source and the electric charge induced in the detector was measured in the temperature range from room temperature up to 450 K. The alpha-ray detection signals were well observed with an oscilloscope at the properly high bias-voltage only for very short time from several seconds to several tens of seconds before the start of the sweeping insulation breakdown. Though this type of the simple detector made of a thin ceramic layer can be hardly used for the energy analysis, it might be effectively applicable to the measurement of the flux of alpha-particles at high temperature. Keywords: alpha-particle detector, ceramic detector, insulation breakdown, surface oxidation, anodic oxidation, alpha-particle flux monitor DOI: 10.1585/pfr.2.S1085 InroductionIt is very important to measure neutrons and confined/escaping alpha-particles in the burning plasma experiments. It is well known that the self-heating of a DT plasma by alpha-particles is the key to realize a selfsustainable thermonuclear plasma. The alpha-diagnostics for a fusion reactor is reviewed in some recent papers [1,2]. As described in the review papers, it is still difficult to measure the distributions of confined and escaping alphaparticles and several proposals to solve such difficulties and related problems are now under examination [2].We find difficulty in using normal alpha-particle detectors such as a semiconductor detector and a scintillation detector under the condition of high temperature. Ceramic material is fundamentally tough against the effects of highenergy particles, high temperature, high voltage and other severe conditions. Thus we have examined the possibility of the substitution of ceramic material for the semiconductor and scintillation material. If an alpha-particle detector is made of ceramic material, such a detector will be more effectively and conveniently used for the alpha-diagnostics. The purpose of this paper is to show fundamental data from some experiments for the development of the ceramic detector. At first, this paper describes how to make two types of ceramic detectors and then shows results on alpha-ray response of the detectors. Experiment Formation of detector samplesSeveral detector samples were formed on two types author's e-mail: iida@eei.eng.osaka-u.ac.jp of substrate, i.e., aluminum and silicon. The thickness of the substrate was 0.5 mm. The surface of each substrate was first polished and then was oxidized for the formation of an insulation layer. Finally an about 400 Å thick silver film was made as an electrode on the insulation layer by an evaporation process. The size of the electrode was 10 mm in diameter.The anodic oxidation method [3] was applied to the aluminum substrate (A-type detector) for the formation of the thick insulation layer on the surface, though the quality of the layer may be poor. A current of 500 mA was gi...

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Section: Inroductionmentioning

confidence: 99%

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Development of a Simple and Tough Alpha-Particle Detector Used at High Temperature

Iida

Sato

Kato

et al. 2007

Plasma and Fusion Research

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“…Alpha particle loss measurements in particular remain extremely difficult [2,3]. A number of standard measurement methods [4][5][6][7][8][9][10] have been proposed but techniques capable of operating in the fusion reactor conditions need further developments. Direct charged particle detection in the fusion alpha energy range (3.6 MeV) relies on two fundamental interaction processes: (i) inelastic scattering on atomic electrons and (ii) nuclear reactions.…”

Section: Introductionmentioning

confidence: 99%

Fusion alpha loss diagnostic for ITER using activation technique

Bonheure

Hult

Orduña

et al. 2011

Fusion Engineering and Design

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“…2͒ and NSTX ͑Ref. 3͒ and are being considered as a lost alpha particle diagnostic for ITER, 4 it may be useful to consider the present proposed solution for these machines as well.…”

Section: Introductionmentioning

confidence: 99%

The anomalous currents in the front foils of the JET lost alpha diagnostic KA-2

Cecil

Kiptily

Salmi

et al. 2010

Review of Scientific Instruments

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We have examined the observed currents in the front foils of the JET Faraday cup lost alpha particle diagnostic KA-2. In particular, we have sought to understand the currents during Ohmic plasmas for which the ion flux at the detectors was initially assumed to be negligible. We have considered two sources of this current: plasma ions ͑both deuterium and impurity͒ in the vicinity of the detector ͑including charge exchange neutrals͒ and photoemission from scattered UV radiation. Based upon modeling and empirical observation, the latter source appears most likely and, moreover, seems to be applicable to the currents in the front foil during ELMy H-mode plasmas. A very thin gold or nickel foil attached to the present detector aperture is proposed as a solution to this problem, and realistic calculations of expected fluxes of lost energetic neutral beam ions during TF ripple experiments are presented as justification of this proposed solution.

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Overview of neutron and confined escaping alpha diagnostics planned for ITER

Cited by 39 publications

References 20 publications

Development of a Simple and Tough Alpha-Particle Detector Used at High Temperature

Development of a Simple and Tough Alpha-Particle Detector Used at High Temperature

Fusion alpha loss diagnostic for ITER using activation technique

The anomalous currents in the front foils of the JET lost alpha diagnostic KA-2

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