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Kremeyer T, Flesch K, Schmitz O, Schlisio G, Wenzel U. Wisconsin In Situ Penning (WISP) gauge: A versatile neutral pressure gauge to measure partial pressures in strong magnetic fields. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:043504. [PMID: 32357759 DOI: 10.1063/1.5125863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 03/13/2020] [Indexed: 06/11/2023]
Abstract
A new type of in-vessel Penning gauge, the Wisconsin In Situ Penning (WISP) gauge, has been developed and successfully operated in the Wendelstein 7-X (W7-X) island divertor baffle and vacuum vessel. The capacity of the quantitative measurements of the neutral reservoir for light impurities, in particular, helium, is important for tokamaks as well as stellarator divertors in order to avoid fuel dilution and radiative energy loss. Penning gauges assisted by spectroscopy are a powerful tool to obtain the total neutral pressure as well as fractional neutral pressures of specific impurities. The WISP gauge is a miniaturized Penning gauge arrangement, which exploits the ambient magnetic field of magnetic confinement fusion experiments to establish the Penning discharge. Then, in situ spectroscopy is conducted to separate the fractional neutral pressures of hydrogen, helium, and possibly also other impurities. The WISP probe head was qualified using the magnetic field of the Magnetized Dusty Plasma Experiment at Auburn University between 0.25 T and 3.5 T [E. Thomas et al., J. Plasma Phys. 81, 345810206 (2015)]. The in-depth quantitative evaluation for hydrogen and helium will be shown as well as an exploration of nitrogen, argon, and neon. A power law scaling between current I and pressure p, I = f(Gas,V) · pn(Gas, B), was shown. The factor f is gas and anode potential dependent, while n is gas and magnetic field strength dependent. Pressure measurements from 0.1 mbar and down to 1 × 10-5 mbar were achieved, demonstrating a reliable operating range for relevant pressure levels in the divertor and main vessel regions in current and future fusion devices, with a time resolution of up to 1 kHz. The lowest achievable pressure measurement increases with an increase in B and can be shifted with the anode potential V. At W7-X, the WISP probe head was mounted on an immersion tube setup that passes through the cryostat and places the probe head close to the plasma. Two probe heads were positioned in different divertor pump gaps, top and bottom, and one close to the plasma on the midplane in one module. The gauges were in situ calibrated together with the ASDEX pressure gauges [G. Haas and H.-S. Bosch, Vacuum 51, 39 (1998)]. Data were taken during the entire operation phase 1.2b, and measurements were coherent with other neutral gas pressure gauges. For the spectroscopic partial pressure measurements, channels of a spectroscopic detection system based on photo-multipliers, a so-called filterscope [R. J. Colchin et al., Rev. Sci. Instrum. 74, 2068 (2003)], provided by the Oak Ridge National Lab were used.
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Affiliation(s)
- T Kremeyer
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - K Flesch
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - O Schmitz
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - G Schlisio
- Max Planck Institute for Plasma Physics, 17491 Greifswald, Germany
| | - U Wenzel
- Max Planck Institute for Plasma Physics, 17491 Greifswald, Germany
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Boivin RL, Luxon JL, Austin ME, Brooks NH, Burrell KH, Doyle EJ, Fenstermacher ME, Gray DS, Groth M, Hsieh CL, Jayakumar RJ, Lasnier CJ, Leonard AW, McKee GR, Moyer RA, Rhodes TL, Rost JC, Rudakov DL, Schaffer MJ, Strait EJ, Thomas DM, Van Zeeland M, Watkins JG, Watson GW, Wong CPC. DIII-D Diagnostic Systems. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst05-a1043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | | | - M. E. Austin
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of Texas–Austin, Austin, Texas
| | | | | | - E. J. Doyle
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of California–Los Angeles, Los Angeles, California
| | - M. E. Fenstermacher
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- Lawrence Livermore National Laboratory, Livermore, California/University of California–Los Angeles, Los Angeles, California
| | - D. S. Gray
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of California–San Diego, La Jolla, California
| | - M. Groth
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- Lawrence Livermore National Laboratory, Livermore, California/University of California–Los Angeles, Los Angeles, California
| | | | - R. J. Jayakumar
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- Lawrence Livermore National Laboratory, Livermore, California/University of California–Los Angeles, Los Angeles, California
| | - C. J. Lasnier
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- Lawrence Livermore National Laboratory, Livermore, California/University of California–Los Angeles, Los Angeles, California
| | | | - G. R. McKee
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of Wisconsin–Madison, Madison, Wisconsin
| | - R. A. Moyer
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of California–San Diego, La Jolla, California
| | - T. L. Rhodes
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of California–Los Angeles, Los Angeles, California
| | - J. C. Rost
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - D. L. Rudakov
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of California–San Diego, La Jolla, California
| | | | | | | | - M. Van Zeeland
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of Wisconsin–Madison, Madison, Wisconsin
| | - J. G. Watkins
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- Sandia National Laboratories, Albuquerque, New Mexico
| | - G. W. Watson
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of California–Irvine, Irvine, California
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DeBoo JC, Baker DR, Wade MR. Transport Studies in DIII-D with Modulated Heat and Particle Sources. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst05-a1054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- J. C. DeBoo
- General Atomics P.O. Box 85608, San Diego, California 92186-5608
| | - D. R. Baker
- General Atomics P.O. Box 85608, San Diego, California 92186-5608
| | - M. R. Wade
- General Atomics P.O. Box 85608, San Diego, California 92186-5608
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Mahdavi MA, Allen SL, Fenstermacher ME, Maingi R, Schaffer MJ, Stambaugh RD, Wade MR. Divertor Physics and Concept Development on DIII-D and Doublet-III Tokamaks. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst05-a1061] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- M. A. Mahdavi
- General Atomics, P.O. Box 85608 San Diego, California 92186-5608
| | - S. L. Allen
- General Atomics, P.O. Box 85608 San Diego, California 92186-5608
| | | | - R. Maingi
- General Atomics, P.O. Box 85608 San Diego, California 92186-5608
| | - M. J. Schaffer
- General Atomics, P.O. Box 85608 San Diego, California 92186-5608
| | - R. D. Stambaugh
- General Atomics, P.O. Box 85608 San Diego, California 92186-5608
| | - M. R. Wade
- General Atomics, P.O. Box 85608 San Diego, California 92186-5608
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Thomas DM, McKee GR, Burrell KH, Levinton F, Foley EL, Fisher RK. Chapter 6: Active Spectroscopy. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst08-a1678] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- D. M. Thomas
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
| | - G. R. McKee
- University of Wisconsin-Madison, Madison, Wisconsin
| | - K. H. Burrell
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
| | | | | | - R. K. Fisher
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
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Lasnier CJ, Allen SL, Boedo JA, Groth M, Brooks NH, McLean A, LaBombard B, Skinner CH, Rudakov DL, West WP, Wong CPC. Chapter 10: First Wall and Operational Diagnostics. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst08-a1682] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- C. J. Lasnier
- Lawrence Livermore National Laboratory, Livermore, California 94550
| | - S. L. Allen
- Lawrence Livermore National Laboratory, Livermore, California 94550
| | - J. A. Boedo
- University of California, San Diego, California 92093
| | - M. Groth
- Lawrence Livermore National Laboratory, Livermore, California 94550
| | - N. H. Brooks
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
| | - A. McLean
- University of Toronto, Toronto, Ontario M3H 5T6, Canada
| | - B. LaBombard
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - C. H. Skinner
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - D. L. Rudakov
- University of California, San Diego, California 92093
| | - W. P. West
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
| | - C. P. C. Wong
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
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Flesch K, Kremeyer T, Schmitz O, Soukhanovskii V, Wenzel U. Development of miniaturized, spectroscopically assisted Penning gauges for fractional helium and hydrogen neutral pressure measurements. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:11E529. [PMID: 27910409 DOI: 10.1063/1.4960815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Direct measurements of the helium (He) fractional neutral pressure in the neutral gas around fusion devices is challenging because of the small mass difference between the abundant D2 molecules and the He ash which will be produced by deuterium-tritium fusion. To study He exhaust, an in situ Penning gauge system is being developed at UW-Madison that is optimized for good pressure and high spectroscopic sensitivity. Three different anode geometries have been studied regarding their vacuum electrostatic fields, light output, and ion current. The light output of the two new anode configurations are at least one order of magnitude above the currently available designs, hence improving the spectroscopic sensitivity at similar total neutral pressure resolution.
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Affiliation(s)
- K Flesch
- Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - T Kremeyer
- Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - O Schmitz
- Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - V Soukhanovskii
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - U Wenzel
- Max Planck Institute for Plasma Physics, 17491 Greifswald, Germany
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