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Banerjee S, Boyle DP, Maan A, Majeski R, Kaita R, Smith D, von Hellermann M, Hansen C, Capecchi W, Elliott D. Feasibility study of a high spatial and time resolution beam emission spectroscopy diagnostic for localized density fluctuation measurements in Lithium Tokamak eXperiment-β (LTX-β). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:113523. [PMID: 36461475 DOI: 10.1063/5.0101834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 09/28/2022] [Indexed: 06/17/2023]
Abstract
Trapped electron mode (TEM) is the main source of turbulence predicted for the unique operation regime of a flat temperature profile under low-recycling conditions in the LTX-β tokamak, while ion temperature gradient driven turbulence may also occur with gas fueling from the edge. To investigate mainly TEM scale density fluctuations, a high spatial and time resolution 2D beam emission spectroscopy (BES) diagnostic is being developed. Apart from spatially localized density turbulence measurement, BES can provide turbulence flow and flow shear dynamics. This BES system will be realized using an avalanche photodiode-based camera and narrow band interference filter. The system can acquire data at 2 MHz. Simulations with the Simulation of Spectra (SOS) code indicate that a high signal to noise ratio can be achieved with the proposed system. This will enable sampling the density fluctuations at this high time resolution. The design considerations and system optimization using the SOS code are presented.
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Affiliation(s)
- Santanu Banerjee
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - D P Boyle
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - A Maan
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - R Majeski
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - R Kaita
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - D Smith
- Department of Physics, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - M von Hellermann
- Institute for Energy and Climate Research IEK-4, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - C Hansen
- Department of Aeronautics and Astronautics, University of Washington, Seattle, Washington 98195, USA
| | - W Capecchi
- Department of Physics, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - D Elliott
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
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Zhou Y, Yu Y, Ke R, Jiang W, Xu M, Xiao C, Cheng Y, Li Z, Li B, Wang Z, Li J, Duan X, Ye M. Design of a Lyman-Alpha-Based BES for edge plasma density diagnosing on the HL-2A tokamak. FUSION ENGINEERING AND DESIGN 2021. [DOI: 10.1016/j.fusengdes.2021.112911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Numerical Considerations for Neutral Beam Spectroscopy Based Diagnostics in the Stellarator TJ-II. JOURNAL OF FUSION ENERGY 2020. [DOI: 10.1007/s10894-020-00248-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Wu Y, McKee G, Yu Y, Ke R, Yan Z, Jaehnig K, Xu M, Kriete M, Morton L, Qin X, Nie L, Wu T, Sun A, Lan T, Yuan B, Liu H, Gong S, Long T, Duan X, Ye M. Development of a 32-channel Beam Emission Spectroscopy diagnostic based on Neutral Beam Injection on HL-2A tokamak. FUSION ENGINEERING AND DESIGN 2020. [DOI: 10.1016/j.fusengdes.2020.111734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Wang HJ, Yu Y, Chen R, Wu YF, Yuan BD, Gong SB, Yu QJ, Lyu B, Shi YJ, Ye MY, Wan BN. Development of beam emission spectroscopy diagnostic on EAST. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:083505. [PMID: 28863624 DOI: 10.1063/1.4997074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Beam Emission Spectroscopy (BES) diagnostic based on Neutron Beam Injection (NBI) on the Experimental Advanced Superconducting Tokamak has been developed. This system consists of 16 × 8 channels which can diagnose the density fluctuation in a rectangular area of about 20 × 10 cm2 in the cross section, whose radial position is adjustable from the core to edge just by means of changing the angle of the rotation mirror. The spatial resolution is about 1-3 cm according to the diagnosed radial position. The temporal resolution is 1 μs. Space calibration of the diagnostic system is done based on the reversibility of the optical path. The NBI modulation experiment shows the success of BES development.
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Affiliation(s)
- H J Wang
- School of Nuclear Science and Technology, University of Science and Technology of China, No. 96 Jinzhai Road, 230026 Hefei, China
| | - Y Yu
- School of Nuclear Science and Technology, University of Science and Technology of China, No. 96 Jinzhai Road, 230026 Hefei, China
| | - R Chen
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - Y F Wu
- School of Nuclear Science and Technology, University of Science and Technology of China, No. 96 Jinzhai Road, 230026 Hefei, China
| | - B D Yuan
- School of Nuclear Science and Technology, University of Science and Technology of China, No. 96 Jinzhai Road, 230026 Hefei, China
| | - S B Gong
- School of Nuclear Science and Technology, University of Science and Technology of China, No. 96 Jinzhai Road, 230026 Hefei, China
| | - Q J Yu
- School of Nuclear Science and Technology, University of Science and Technology of China, No. 96 Jinzhai Road, 230026 Hefei, China
| | - B Lyu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - Y J Shi
- School of Nuclear Science and Technology, University of Science and Technology of China, No. 96 Jinzhai Road, 230026 Hefei, China
| | - M Y Ye
- School of Nuclear Science and Technology, University of Science and Technology of China, No. 96 Jinzhai Road, 230026 Hefei, China
| | - B N Wan
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
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Field AR, Dunai D, Gaffka R, Ghim YC, Kiss I, Mészáros B, Krizsanóczi T, Shibaev S, Zoletnik S. Beam emission spectroscopy turbulence imaging system for the MAST spherical tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:013508. [PMID: 22299952 DOI: 10.1063/1.3669756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A new beam emission spectroscopy turbulence imaging system has recently been installed onto the MAST spherical tokamak. The system utilises a high-throughput, direct coupled imaging optics, and a single large interference filter for collection of the Doppler shifted D(α) emission from the ~2 MW heating beam of ~70 keV injection energy. The collected light is imaged onto a 2D array detector with 8 × 4 avalanche photodiode sensors which is incorporated into a custom camera unit to perform simultaneous 14-bit digitization at 2 MHz of all 32 channels. The array is imaged at the beam to achieve a spatial resolution of ~2 cm in the radial (horizontal) and poloidal (vertical) directions, which is sufficient for detection of the ion-scale plasma turbulence. At the typical photon fluxes of ~10(11) s(-1) the achieved signal-to-noise ratio of ~300 at the 0.5 MHz analogue bandwidth is sufficient for detection of relative density fluctuations at the level of a few 0.1%. The system is to be utilised for the study of the characteristics of the broadband, ion-scale turbulence, in particular its interaction with flow shear, as well as coherent fluctuations due to various types of MHD activity.
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Affiliation(s)
- A R Field
- EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon, United Kingdom
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Kiss IG, Mészáros B, Dunai D, Zoletnik S, Krizsanóczi T, Field AR, Gaffka R. Mechanical design of the two dimensional beam emission spectroscopy diagnostics on mast. FUSION ENGINEERING AND DESIGN 2011. [DOI: 10.1016/j.fusengdes.2010.11.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Dunai D, Zoletnik S, Sárközi J, Field AR. Avalanche photodiode based detector for beam emission spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:103503. [PMID: 21034087 DOI: 10.1063/1.3488458] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
An avalanche photodiode based (APD) detector for the visible wavelength range was developed for low light level, high frequency beam emission spectroscopy (BES) experiments in fusion plasmas. This solid state detector has higher quantum efficiency than photomultiplier tubes, and unlike normal photodiodes, it has internal gain. This paper describes the developed detector as well as the noise model of the electronic circuit. By understanding the noise sources and the amplification process, the optimal amplifier and APD reverse voltage setting can be determined, where the signal-to-noise ratio is the highest for a given photon flux. The calculations are compared to the absolute calibration results of the implemented circuit. It was found that for a certain photon flux range, relevant for BES measurements (≈10(8)-10(10) photons/s), the new detector is superior to both photomultipliers and photodiodes, although it does not require cryogenic cooling of any component. The position of this photon flux window sensitively depends on the parameters of the actual experimental implementation (desired bandwidth, detector size, etc.) Several detector units based on these developments have been built and installed in various tokamaks. Some illustrative results are presented from the 8-channel trial BES system installed at Mega-Ampere Spherical Tokamak (MAST) and the 16-channel BES system installed at the Torus Experiment for Technology Oriented Research (TEXTOR).
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Affiliation(s)
- D Dunai
- KFKI Research Institute for Particle and Nuclear Physics, EURATOM Association, P.O. Box 49, H-1525 Budapest, Hungary
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Ghim Kim YC, Field AR, Zoletnik S, Dunai D. Calculation of spatial response of 2D beam emission spectroscopy diagnostic on MAST. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:10D713. [PMID: 21033906 DOI: 10.1063/1.3479037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The beam emission spectroscopy (BES) turbulence diagnostic on MAST is to be upgraded in June 2010 from a one-dimensional trial system to a two-dimensional imaging system (8 radial×4 poloidal channels) based on a newly developed avalanche photodiode array camera. The spatial resolution of the new system is calculated in terms of the point spread function to account for the effects of field-line curvature, observation geometry, the finite lifetime of the excited state of the beam atoms, and beam attenuation and divergence. It is found that the radial spatial resolution is ∼2-3 cm and the poloidal spatial resolution ∼1-5 cm depending on the radial viewing location. The absolute number of detected photons is also calculated, hence the photon noise level can be determined.
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Affiliation(s)
- Young-Chul Ghim Kim
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford OX1 3NP, United Kingdom
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