Development of diagnostic beams for alpha particle measurement on ITER

Sasao, M.; Taniike, Akira; Nomura, I.; Wada, M.; Yamaoka, H.; Satō, Masayasu

doi:10.1088/0029-5515/35/12/i25

Cited by 22 publications

(8 citation statements)

References 16 publications

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“…The properties of high-Z materials have been studied under plasma and beam irradiation, but there is not enough systematic experimental data (especially for polycrystalline materials) to simulate accurately the phenomena in the plasma boundary, and therefore to design a divertor system for the future fusion device. Recently, we have developed an experimental system to study fundamental processes of surface negative ion production for negative ion beam based plasma diagnostic system [1][2][3]. The angular resolved energy distributions of reflected ions from a target sample can be measured Fig.…”

Section: Introductionmentioning

confidence: 99%

Angular resolved energy distributions of low energy light ions reflected from a polycrystalline Mo surface

Yamaoka¹,

Matsumoto²,

Nishiura³

et al. 2005

Journal of Nuclear Materials

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Section: Introductionmentioning

confidence: 99%

Angular resolved energy distributions of low energy light ions reflected from a polycrystalline Mo surface

Yamaoka¹,

Matsumoto²,

Nishiura³

et al. 2005

Journal of Nuclear Materials

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“…Due to the strong beam attenuation, the measurement range is limited to r/a > 0.6. Charge exchange neutralization with high energy neutral beams was proposed [40]. This method uses a tangential 3 He beam with an energy of 0.8-1.5 MeV.…”

Section: Fusion Product Measurementsmentioning

confidence: 99%

Chapter 7: Diagnostics

et al. 2007

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In order to support the operation of ITER and the planned experimental programme an extensive set of plasma and first wall measurements will be required. The number and type of required measurements will be similar to those made on the present-day large tokamaks while the specification of the measurements-time and spatial resolutions, etc-will in some cases be more stringent. Many of the measurements will be used in the real time control of the plasma driving a requirement for very high reliability in the systems (diagnostics) that provide the measurements.The implementation of diagnostic systems on ITER is a substantial challenge. Because of the harsh environment (high levels of neutron and gamma fluxes, neutron heating, particle bombardment) diagnostic system selection and design has to cope with a range of phenomena not previously encountered in diagnostic design. Extensive design and R&D is needed to prepare the systems. In some cases the environmental difficulties are so severe that new diagnostic techniques are required.The starting point in the development of diagnostics for ITER is to define the measurement requirements and develop their justification. It is necessary to include all the plasma parameters needed to support the basic and advanced operation (including active control) of the device, machine protection and also those needed to support the physics programme. Once the requirements are defined, the appropriate (combination of) diagnostic techniques can be selected and their implementation onto the tokamak can be developed. The selected list of diagnostics is an important guideline for identifying dedicated research and development needs in the area of ITER diagnostics.This paper gives a comprehensive overview of recent progress in the field of ITER diagnostics with emphasis on the implementation issues. After a discussion of the measurement requirements for plasma parameters in ITER and their justifications, recent progress in the field of diagnostics to measure a selected set of plasma parameters is presented. The integration of the various diagnostic systems onto the ITER tokamak is described. Generic research and development in the field of irradiation effects on materials and environmental effects on first mirrors are briefly presented. The paper ends with an assessment of the measurement capability for ITER and a forward of what will be gained from operation of the various diagnostic systems on ITER in preparation for the machines that will follow ITER. Performance assessment relative to requirements Design meets requirements S339 A.J.H. Donné et alPhysics Basis [7] and remains essentially the same. However, for ITER, the specific limits have changed. 2.1.2.Measurements needed for plasma control and evaluation. The measurements needed for plasma control and evaluation are naturally directly linked to the experimental programme, and particularly to the operating phase (i.e. H, D or D/T) and the operating scenario (H-mode, hybrid, etc). Since there is expected to be a phased introduction of po...

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“…In this method, plasma perturbation should be studied carefully. Charge exchange neutralization with high-energy neutral beams was proposed by Sasao et al [19]. This method uses a tangential 3 He beam with energy of 0.8-1.5 MeV injected from port 6.…”

Section: Confined Alpha Measurementmentioning

confidence: 99%

Overview of neutron and confined escaping alpha diagnostics planned for ITER

Sasao

Krasilnikov

Nishitani

et al. 2004

Plasma Phys. Control. Fusion

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Fusion product measurements planned for ITER are reviewed from the viewpoint of alpha particle-related physics studies. Recent advances in fusion plasma physics have extended the desirable measurement requirements to the megahertz region for neutron emission rate, better resolution of neutron profiles for the study of internal transport barriers (ITBs), etc. Employing threshold counters and/or scintillation detectors confers megahertz capability on neutron emission rate measurement. The changes in the neutron/alpha particle birth profile due to the formation of ITB and its deviation from uniformity on the magnetic flux surface can be measured by addition of eight viewing chords in an equatorial port plug and seven viewing chords from the divertor to the original radial neutron camera. On the other hand, it is still difficult to measure the distributions of confined and escaping alpha particles. Several proposals to resolve these difficulties are currently under investigation.

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Development of diagnostic beams for alpha particle measurement on ITER

Cited by 22 publications

References 16 publications

Angular resolved energy distributions of low energy light ions reflected from a polycrystalline Mo surface

Angular resolved energy distributions of low energy light ions reflected from a polycrystalline Mo surface

Chapter 7: Diagnostics

Overview of neutron and confined escaping alpha diagnostics planned for ITER

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