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Malinowski K, Chernyshova M, Jabłoński S, Czarski T, Wojeński A, Kasprowicz G. Two-Dimensional Plasma Soft X-ray Radiation Imaging System: Optimization of Amplification Stage Based on Gas Electron Multiplier Technology. SENSORS (BASEL, SWITZERLAND) 2024; 24:5113. [PMID: 39204809 PMCID: PMC11359351 DOI: 10.3390/s24165113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2024] [Revised: 07/17/2024] [Accepted: 07/22/2024] [Indexed: 09/04/2024]
Abstract
The objective of the proposed research is to develop plasma soft X-ray (SXR) radiation imaging that includes spectral information in addition to standard SXR tomography for the purpose of studying, for example, tungsten transport and its interplay with magnetohydrodynamics (MHD) in tokamak plasmas in an ITER-relevant approach. The SXR radiation provides valuable information about both aspects, particularly when measured with high spatial and temporal resolution and when tomographic reconstructions are performed. The spectral data will facilitate the tracking of both light and high-Z impurities. This approach is pertinent to both the advancement of a detailed understanding of physics and the real-time control of plasma, thereby preventing radiative collapses. The significance of this development lies in its ability to provide three-dimensional plasma tomography, a capability that extends beyond the scope of conventional tomography. The utilization of two-dimensional imaging capabilities inherent to Gas Electron Multiplier (GEM) detectors in a toroidal view, in conjunction with the conventional poloidal tomography, allows for the acquisition of three-dimensional information, which should facilitate the study of, for instance, the interplay between impurities and MHD activities. Furthermore, this provides a valuable opportunity to investigate the azimuthal asymmetry of tokamak plasmas, a topic that has rarely been researched. The insights gained from this research could prove invaluable in understanding other toroidal magnetically confined plasmas, such as stellarators, where comprehensive three-dimensional measurements are essential. To illustrate, by attempting to gain access to anisotropic radiation triggered by magnetic reconnection or massive gas injections, such diagnostics will provide the community with enhanced experimental tools to understand runaway electrons (energy distribution and spatial localization) and magnetic reconnection (spatial localization, speed…). This work forms part of the optimization studies of a detecting unit proposed for use in such a diagnostic system, based on GEM technology. The detector is currently under development with the objective of achieving the best spatial resolution feasible with this technology (down to approximately 100 µm). The diagnostic design focuses on the monitoring of photons within the 2-15 keV range. The findings of the optimization studies conducted on the amplification stage of the detector, particularly with regard to the geometrical configuration of the GEM foils, are presented herein. The impact of hole shape and spacing in the amplifying foils on the detector parameters, including the spatial size of the avalanches and the electron gain/multiplication, has been subjected to comprehensive numerical analysis through the utilization of Degrad (v. 3.13) and Garfield++ (v. bd8abc76) software. The results obtained led to the identification of two configurations as the most optimal geometrical configurations of the amplifying foil for the three-foil GEM system for the designed detector. The first configuration comprises cylindrical holes with a diameter of 70 μm, while the second configuration comprises biconical holes with diameters of 70/50/70 μm. Both configurations had a hole spacing of 120 μm.
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Affiliation(s)
- Karol Malinowski
- Institute of Plasma Physics and Laser Microfusion, Hery 23, 01-497 Warsaw, Poland; (K.M.); (S.J.); (T.C.)
| | - Maryna Chernyshova
- Institute of Plasma Physics and Laser Microfusion, Hery 23, 01-497 Warsaw, Poland; (K.M.); (S.J.); (T.C.)
| | - Sławomir Jabłoński
- Institute of Plasma Physics and Laser Microfusion, Hery 23, 01-497 Warsaw, Poland; (K.M.); (S.J.); (T.C.)
| | - Tomasz Czarski
- Institute of Plasma Physics and Laser Microfusion, Hery 23, 01-497 Warsaw, Poland; (K.M.); (S.J.); (T.C.)
| | - Andrzej Wojeński
- Institute of Electronic Systems, Warsaw University of Technology, Nowowiejska 15/19, 00-665 Warsaw, Poland; (A.W.); (G.K.)
| | - Grzegorz Kasprowicz
- Institute of Electronic Systems, Warsaw University of Technology, Nowowiejska 15/19, 00-665 Warsaw, Poland; (A.W.); (G.K.)
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2
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Ramaiya N, Manchanda R, Chowdhuri MB, Yadava N, Dey R, Kumar A, Shah K, Patel S, Jadeja KA, Patel KM, Kumar R, Aich S, Pathak SK, Tanna RL, Ghosh J. Initial results from near-infrared spectroscopy on ADITYA-U tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:113552. [PMID: 36461425 DOI: 10.1063/5.0101850] [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: 09/12/2022] [Indexed: 06/17/2023]
Abstract
Spectroscopy in vacuum ultraviolet (VUV) and visible ranges plays an important role in the investigation and diagnosis of tokamak plasmas. However, under harsh environmental conditions of fusion grade devices, such as ITER, VUV-visible systems encounter many issues due to the degradation of optical components used in such systems. Here, near-infrared (NIR) spectroscopy has become an effective tool in understanding the edge plasma dynamics. Considering its importance, a NIR spectroscopic diagnostic has been developed and installed on the ADITYA-U tokamak. The system consists of a 0.5 m spectrometer having three gratings with different groove densities, and it is coupled with a linear InGaAs photodiode array. Radiation from the ADITYA-U edge plasma has been collected using a collimating lens and optical fiber combination and transported to the spectrometer. The spectrum in the NIR range from the ADITYA-U plasma has been recorded using this system, in which Paβ and Paγ along with many spectral lines from neutral and singly ionized impurities have been observed. The influxes of H and C have been estimated from measurements. The H influx value is found to be 2.8 × 1016 and 1.9 × 1016 particles cm-2 s-1 from neutral hydrogen lines Hα and Paβ, respectively, and the C influx value is found to be 3.5 × 1015 and 2.9 × 1015 particles cm-2 s-1 from the neutral carbon and singly ionized carbon, respectively. A good agreement is seen between these results and the results obtained by using a routine photomultiplier tube based diagnostic.
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Affiliation(s)
- N Ramaiya
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - R Manchanda
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - M B Chowdhuri
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - N Yadava
- Institute of Science, Nirma University, Ahmedabad 382 481, India
| | - R Dey
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - A Kumar
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - K Shah
- Department of Physics, Pandit Deendayal Energy University, Raisan, Gandhinagar 382 007, India
| | - S Patel
- Department of Physics, Pandit Deendayal Energy University, Raisan, Gandhinagar 382 007, India
| | - K A Jadeja
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - K M Patel
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - R Kumar
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - S Aich
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - S K Pathak
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - R L Tanna
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - J Ghosh
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
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Zhang XY, Qing WJ, Zhang XL, Jiao SD, Li Q, Ding YH, Wang L, Cheng ZF. Upgrade of vacuum ultraviolet spectroscopy system on J-TEXT tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:073503. [PMID: 34340446 DOI: 10.1063/5.0043449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
The vacuum ultraviolet (VUV) spectroscopy system on the Joint Texas Experimental Tokamak has been upgraded to achieve fast acquisition for the study of impurity transport in transient modulated experiments. In this upgrade, the previous high-energy charge-coupled device detector was replaced by a microchannel plate with a CsI-coated photocathode and P43 phosphor to transform the VUV light to visible light, which is then acquired by a high-speed electron-multiplying charge-coupled device. Two-stage focusing was achieved using a reference slit plate illuminated successively by a green light source and the Lyman series hydrogen spectral lines from the vacuum-conditioning plasma. The spatial resolution was evaluated as ∼4 mm based on the level of image blurring from the alignment plate. A response time of ∼2 ms was obtained with the ten-vertical-track setup.
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Affiliation(s)
- X Y Zhang
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - W J Qing
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - X L Zhang
- Advanced Energy Research Center, Shenzhen University, Shenzhen 518060, China
| | - S D Jiao
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Q Li
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Y H Ding
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - L Wang
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Z F Cheng
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, Huazhong University of Science and Technology, Wuhan 430074, China
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4
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Li Q, Cheng Z, Zhang X, Zhang X, Jiao S, Qing W, Chen Z. Design of fast response Doppler spectroscopy system for HUST field-reversed configuration device. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:063522. [PMID: 34243503 DOI: 10.1063/5.0043310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 06/08/2021] [Indexed: 06/13/2023]
Abstract
A fast response Doppler spectroscopy system with high throughput and high resolution is under development for studying the drifting velocity, rotation velocity, and ion temperature on the HUST field-reversed configuration (HFRC) device. The system has been designed to observe the spectral line of oxygen V (O V) ion emission at 278.1 nm (1s22s3p → 1s22s3s) over the lifetime (∼0.5 ms) of the FRC plasma. A high throughput Czerny-Turner monochromator with 3600 g/mm grating and 670 mm focal length is applied to achieve high spectral resolution; a 32-channel multi-anode photomultiplier tube (PMT) detector is utilized to achieve the high-speed response of up to 1 MHz; a 1D magnification optics combined with a cylindrical lens assembly and a fiber optic expansion is developed to magnify the spectral dispersion fitting the PMT channel interval. Through the ray-tracing analysis, the system's final spectral resolution is evaluated to be ∼0.03 nm. Taking into account the system sensitivity and O V line emissivity in HFRC plasma, the system is expected to be workable with the temporal response of 1 µs.
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Affiliation(s)
- Qiong Li
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhifeng Cheng
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xiaolong Zhang
- Advanced Energy Research Center, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - XiaoYi Zhang
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shaodong Jiao
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wanjun Qing
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhipeng Chen
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
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5
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Huang XL, Zhang YP, Zhu YB, Li X, He L, Li YX, Zhou J, Cheng SK, Yang YM, Bai RH, Zhao X, Tao RY, Chen B, Dai LL, Zeng GQ, Liu Y, Liu MS. Toroidal soft x-ray array on the EXL-50 spherical tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:053501. [PMID: 34243359 DOI: 10.1063/5.0040511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/12/2021] [Indexed: 06/13/2023]
Abstract
A toroidal soft x-ray array system for spectrum and intensity measurements on the EXL-50 spherical tokamak is described. Silicon drift detectors and digital multichannel analyzers are adopted for all 21 channels of the array, and an average energy resolution of 147 eV at 5.89 keV has been achieved at count rates over 500 kcps. In total, 20 channels of the array are symmetrically observed in both co- and counter-current directions on the EXL-50 mid-plane with a spatial resolution of around 10 cm, and the remaining one serves as a background reference channel. Tungsten emissions from tungsten coating of the limiters on the central post are observed. The influence of hard x rays on measured soft x-ray spectra and system operation is discussed.
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Affiliation(s)
- X L Huang
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - Y P Zhang
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
| | - Y B Zhu
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - X Li
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
| | - L He
- Chengdu University of Technology, Chengdu 610059, China
| | - Y X Li
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - J Zhou
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
| | - S K Cheng
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - Y M Yang
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - R H Bai
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - X Zhao
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - R Y Tao
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - B Chen
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - L L Dai
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - G Q Zeng
- Chengdu University of Technology, Chengdu 610059, China
| | - Y Liu
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
| | - M S Liu
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
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6
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Donné AJH, Barth CJ, Weisen H. Chapter 4: Laser-Aided Plasma Diagnostics. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst08-a1676] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- A. J. H. Donné
- Association EURATOM-FOM FOM-Institute for Plasma Physics Rijnhuizen, Partner in the Trilateral Euregio Cluster P.O. Box 1207, 3430 BE Nieuwegein, The Netherlands
| | - C. J. Barth
- Association EURATOM-FOM FOM-Institute for Plasma Physics Rijnhuizen, Partner in the Trilateral Euregio Cluster P.O. Box 1207, 3430 BE Nieuwegein, The Netherlands
| | - H. Weisen
- Centre de Recherches en Physique des Plasmas, Association EURATOM-Suisse Ecole Polytechnique Fédérale de Lausanne, EPFL, 1015 Lausanne, Switzerland
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7
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Failure mode analysis of preliminary design of ITER divertor impurity monitor. FUSION ENGINEERING AND DESIGN 2016. [DOI: 10.1016/j.fusengdes.2016.07.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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8
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Widmann K, Beiersdorfer P, Magee EW, Boyle DP, Kaita R, Majeski R. High-resolution grazing-incidence grating spectrometer for temperature measurements of low-Z ions emitting in the 100-300 Å spectral band. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:11D630. [PMID: 25430206 DOI: 10.1063/1.4894388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have constructed a high-resolution grazing-incidence spectrometer designed for measuring the ion temperature of low-Z elements, such as Li(+) or Li(2 +), which radiate near 199 Å and 135 Å, respectively. Based on measurements at the Livermore Electron Beam Ion Trap we have shown that the instrumental resolution is better than 48 mÅ at the 200 Å setting and better than 40 mÅ for the 135-Å range. Such a high spectral resolution corresponds to an instrumental limit for line-width based temperature measurements of about 45 eV for the 199 Å Li(+) and 65 eV for the 135 Å Li(2 +) lines. Recently obtained survey spectra from the Lithium Tokamak Experiment at the Princeton Plasma Physics Laboratory show the presence of these lithium emission lines and the expected core ion temperature of approximately 70 eV is sufficiently high to demonstrate the feasibility of utilizing our high-resolution spectrometer as an ion-temperature diagnostic.
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Affiliation(s)
- K Widmann
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - P Beiersdorfer
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - E W Magee
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - D P Boyle
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - R Kaita
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - R Majeski
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
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9
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Lepson JK, Beiersdorfer P, Clementson J, Bitter M, Hill KW, Kaita R, Skinner CH, Roquemore AL, Zimmer G. High-resolution time-resolved extreme ultraviolet spectroscopy on NSTX. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:10D520. [PMID: 23126861 DOI: 10.1063/1.4731753] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report on upgrades to the flat-field grazing-incidence grating spectrometers X-ray and Extreme Ultraviolet Spectrometer (XEUS) and Long-Wavelength Extreme Ultraviolet Spectrometer (LoWEUS), at the National Spherical Torus Experiment (NSTX) at the Princeton Plasma Physics Laboratory. XEUS employs a variable space grating with an average spacing of 2400 lines/mm and covers the 9-64 Å wavelength band, while LoWEUS has an average spacing of 1200 lines/mm and is positioned to monitor the 90-270 Å wavelength band. Both spectrometers have been upgraded with new cameras that achieve 12.5 ms time resolution. We demonstrate the new time resolution capability by showing the time evolution of iron in the NSTX plasma.
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Affiliation(s)
- J K Lepson
- Space Sciences Laboratory, University of California, Berkeley, California 94720, USA.
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10
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Zhou H, Cui Z, Morita S, Fu B, Goto M, Sun P, Dong C, Gao Y, Xu Y, Lu P, Yang Q, Duan X. Absolute sensitivity calibration of vacuum and extreme ultraviolet spectrometer systems and Z(eff) measurement based on bremsstrahlung continuum in HL-2A tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:10D507. [PMID: 23126850 DOI: 10.1063/1.4729671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A grazing-incidence flat-field extreme ultraviolet (EUV) spectrometer has been newly developed in HL-2A tokamak. Typical spectral lines are observed from intrinsic impurities of carbon, oxygen, iron, and extrinsic impurity of helium in the wavelength range of 20 Å-500 Å. Bremsstrahlung continuum is measured at different electron densities of HL-2A discharges to calibrate absolute sensitivity of the EUV spectrometer system and to measure effective ionic charge, Z(eff). The sensitivity of a vacuum ultraviolet (VUV) spectrometer system is also absolutely calibrated in overlapped wavelength range of 300 Å-500 Å by comparing the intensity between VUV and EUV line emissions.
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Affiliation(s)
- Hangyu Zhou
- Southwestern Institute of Physics, PO Box 432, Chengdu 610041, China.
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11
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Weller ME, Safronova AS, Clementson J, Kantsyrev VL, Safronova UI, Beiersdorfer P, Petkov EE, Wilcox PG, Osborne GC. Extreme ultraviolet spectroscopy and modeling of Cu on the SSPX Spheromak and laser plasma "Sparky". THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:10E101. [PMID: 23126923 DOI: 10.1063/1.4727916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Impurities play a critical role in magnetic fusion research. In large quantities, impurities can cool and dilute plasma creating problems for achieving ignition and burn; however in smaller amounts the impurities could provide valuable information about several plasma parameters through the use of spectroscopy. Many impurity ions radiate within the extreme ultraviolet (EUV) range. Here, we report on spectra from the silver flat field spectrometer, which was implemented at the Sustained Spheromak Physics experiment (SSPX) to monitor ion impurity emissions. The chamber within the SSPX was made of Cu, which makes M-shell Cu a prominent impurity signature. The Spect3D spectral analysis code was utilized to identify spectral features in the range of 115-315 Å and to more fully understand the plasma conditions. A second set of experiments was carried out on the compact laser-plasma x-ray∕EUV facility "Sparky" at UNR, with Cu flat targets used. The EUV spectra were recorded between 40-300 Å and compared with results from SSPX.
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Affiliation(s)
- M E Weller
- University of Nevada, Reno, Nevada 89557, USA.
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12
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Jones B, Jennings CA, Bailey JE, Rochau GA, Maron Y, Coverdale CA, Yu EP, Hansen SB, Ampleford DJ, Lake PW, Dunham G, Cuneo ME, Deeney C, Fisher DV, Fisher VI, Bernshtam V, Starobinets A, Weingarten L. Doppler measurement of implosion velocity in fast Z-pinch x-ray sources. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:056408. [PMID: 22181529 DOI: 10.1103/physreve.84.056408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 05/13/2011] [Indexed: 05/31/2023]
Abstract
The observation of Doppler splitting in K-shell x-ray lines emitted from optically thin dopants is used to infer implosion velocities of up to 70 cm/μs in wire-array and gas-puff Z pinches at drive currents of 15-20 MA. These data can benchmark numerical implosion models, which produce reasonable agreement with the measured velocity in the emitting region. Doppler splitting is obscured in lines with strong opacity, but red-shifted absorption produced by the cooler halo of material backlit by the hot core assembling on axis can be used to diagnose velocity in the trailing mass.
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Affiliation(s)
- B Jones
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
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13
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Williamson KM, Kantsyrev VL, Safronova AS, Wilcox PG, Cline W, Batie S, LeGalloudec B, Nalajala V, Astanovitsky A. Grazing incidence extreme ultraviolet spectrometer fielded with time resolution in a hostile z-pinch environment. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:093506. [PMID: 21974586 DOI: 10.1063/1.3626930] [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
This recently developed diagnostic was designed to allow for time-gated spectroscopic study of the EUV radiation (4 nm < λ < 15 nm) present during harsh wire array z-pinch implosions. The spectrometer utilizes a 25 μm slit, an array of 3 spherical blazed gratings at grazing incidence, and a microchannel plate (MCP) detector placed in an off-Rowland position. Each grating is positioned such that its diffracted radiation is cast over two of the six total independently timed frames of the MCP. The off-Rowland configuration allows for a much greater spectral density on the imaging plate but only focuses at one wavelength per grating. The focal wavelengths are chosen for their diagnostic significance. Testing was conducted at the Zebra pulsed-power generator (1 MA, 100 ns risetime) at the University of Nevada, Reno on a series of wire array z-pinch loads. Within this harsh z-pinch environment, radiation yields routinely exceed 20 kJ in the EUV and soft x-ray. There are also strong mechanical shocks, high velocity debris, sudden vacuum changes during operation, energic ion beams, and hard x-ray radiation in excess of 50 keV. The spectra obtained from the precursor plasma of an Al double planar wire array contained lines of Al IX and AlX ions indicating a temperature near 60 eV during precursor formation. Detailed results will be presented showing the fielding specifications and the techniques used to extract important plasma parameters using this spectrometer.
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Affiliation(s)
- K M Williamson
- Plasma Physics and Diagnostics Laboratory, Physics Department, University of Nevada, Reno, Nevada 89557, USA
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14
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Safronova AS, Ouart ND, Lepson JK, Beiersdorfer P, Stratton B, Bitter M, Kantsyrev VL, Cox PG, Shlyaptseva V, Williamson KM. X-ray spectroscopy of Cu impurities on NSTX and comparison with Z-pinch plasmas. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:10E305. [PMID: 21034004 DOI: 10.1063/1.3478673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
X-ray spectroscopy of mid-Z metal impurities is important in the study of tokamak plasmas and may reveal potential problems if their contribution to the radiated power becomes substantial. The analysis of the data from a high-resolution x-ray and extreme ultraviolet grating spectrometer, XEUS, installed on NSTX, was performed focused on a detailed study of x-ray spectra in the range 7-18 Å. These spectra include not only commonly seen iron spectra but also copper spectra not yet employed as an NSTX plasma impurity diagnostic. In particular, the L-shell Cu spectra were modeled and predictions were made for identifying contributions from various Cu ions in different spectral bands. Also, similar spectra, but from much denser Cu plasmas produced on the UNR Z-pinch facility and collected using the convex-crystal spectrometer, were analyzed and compared with NSTX results.
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Clementson J, Beiersdorfer P, Magee EW. Grazing-incidence spectrometer on the SSPX spheromak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:10F538. [PMID: 19044680 DOI: 10.1063/1.2965776] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The silver flat field spectrometer (SFFS) is a high-resolution grazing-incidence diagnostic for magnetically confined plasmas. It covers the wavelength range of 25-450 A with a resolution of Delta lambda=0.3 A full width at half maximum. The SFFS employs a spherical 1200 lines/mm grating for flat-field focusing. The imaging is done using a backilluminated Photometrics charge-coupled device camera allowing a bandwidth of around 200 A per spectrum. The spectrometer has been used for atomic spectroscopy on electron beam ion traps and for plasma spectroscopy on magnetic confinement devices. Here we describe the design of the SFFS and the spectrometer setup at the sustained spheromak physics experiment in Livermore.
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Affiliation(s)
- J Clementson
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
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Soukhanovskii VA. Near-infrared spectroscopy for burning plasma diagnostic applications. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:10F539. [PMID: 19044681 DOI: 10.1063/1.2964230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Ultraviolet and visible (UV-VIS, 200-750 nm) atomic spectroscopy of neutral and ionized fuel species (H, D, T, and Li) and impurities (e.g., He, Be, C, and W) is a key element of plasma control and diagnosis on International Thermonuclear Experimental Reactor and future magnetically confined burning plasma experiments (BPXs). Spectroscopic diagnostic implementation and performance issues that arise in the BPX harsh nuclear environment in the UV-VIS range, e.g., degradation of first mirror reflectivity under charge-exchange atom bombardment (erosion) and impurity deposition, permanent and dynamic loss of window, and optical fiber transmission under intense neutron and gamma-ray fluxes, are either absent or not as severe in the near-infrared (NIR, 750-2000 nm) range. An initial survey of NIR diagnostic applications has been undertaken on the National Spherical Torus Experiment. It is demonstrated that NIR spectroscopy can be used for machine protection and plasma control applications, as well as contribute to plasma performance evaluation and physics studies. Emission intensity estimates demonstrate that NIR measurements are possible in the BPX plasma operating parameter range. Complications in the NIR range due to the parasitic background emissions are expected to occur at very high plasma densities, low impurity densities, and at high plasma-facing component temperatures.
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Affiliation(s)
- V A Soukhanovskii
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
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