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Bonofiglo PJ, Kiptily V, Goloborodko V, Štancar Ž, Podestà M, Cecil FE, Challis CD, Hobirk J, Kappatou A, Lerche E, Carvalho IS, Garcia J, Mailloux J, Maggi CF, Meigs AG. Lost alpha Faraday cup foil noise characterization during Joint European Torus plasma post-processing analysis. Rev Sci Instrum 2022; 93:093527. [PMID: 36182470 DOI: 10.1063/5.0099314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/18/2022] [Indexed: 06/16/2023]
Abstract
Capacitive plasma pickup is a well-known and difficult problem for plasma-facing edge diagnostics. This problem must be addressed to ensure an accurate and robust interpretation of the real signal measurements vs noise. The Faraday cup fast ion loss detector array of the Joint European Torus (JET) is particularly prone to this issue and can be used as a testbed to prototype solutions. The issue of separation and distinction between warranted fast ion signal and electromagnetic plasma noise has traditionally been solved with hardware modifications, but a more versatile post-processing approach is of great interest. This work presents post-processing techniques to characterize the signal noise. While hardware changes and advancements may be limited, the combination with post-processing procedures allows for more rapid and robust analysis of measurements. The characterization of plasma pickup noise is examined for alpha losses in a discharge from JET's tritium campaign. In addition to highlighting the post-processing methodology, the spatial sensitivity of the detector array is also examined, which presents significant advantages for the physical interpretation of fast ion losses.
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Affiliation(s)
- P J Bonofiglo
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - V Kiptily
- UKAEA, CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - V Goloborodko
- Kyiv Institute for Nuclear Research, Prospekt Nauky 47, Kyiv 03680, Ukraine
| | - Ž Štancar
- UKAEA, CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - M Podestà
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - F E Cecil
- Colorado School of Mines, Golden, Colorado 80401, USA
| | - C D Challis
- UKAEA, CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - J Hobirk
- Max-Planck-Institut für Plasmaphysik, D-85748 Garching, Germany
| | - A Kappatou
- Max-Planck-Institut für Plasmaphysik, D-85748 Garching, Germany
| | - E Lerche
- UKAEA, CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - I S Carvalho
- Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal
| | - J Garcia
- CEA-IRFM, F-13108 Saint Paul Lez Durance, France
| | - J Mailloux
- UKAEA, CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - C F Maggi
- UKAEA, CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - A G Meigs
- UKAEA, CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
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Conway NJ, Cackett AJ, Maggi CF, Meigs AG, Zastrow KD, Biewer TM, Hillis DL. Upgrades to the in-vessel calibration light source on JET. Rev Sci Instrum 2018; 89:10K107. [PMID: 30399841 DOI: 10.1063/1.5037713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 06/06/2018] [Indexed: 06/08/2023]
Abstract
Since 2010, an in-vessel calibration light source (ICLS) has been used periodically on JET to calibrate a range of diagnostics at UV, visible, and IR wavelengths. During shutdowns, the ICLS (which is essentially an integrating sphere) is positioned within the vacuum vessel by the remote handling (RH) system. Following the 2013 calibration runs, several changes were made to improve the efficiency and quality of the calibrations. Among these was the replacement of a 20 m "umbilical" cable which carried power and other electrical signals through a vessel port to/from a control cubicle. A lightweight 2 m cable now plugs directly into a single connector on the RH manipulator system, greatly reducing the time required for deployment and improving operational flexibility; e.g., the vessel access "floor" no longer needs to be installed. This change also means the system would be compatible with calibrations after a high neutron-fluence period of operation. An on-board micro-spectrometer now allows for real-time verification of the emitted spectrum. Finally, new "baffles" were designed and installed within the integrating sphere itself, greatly improving the spectral radiance uniformity at non-normal viewing angles (necessary due to orientation uncertainties with the RH system).
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Affiliation(s)
- N J Conway
- UKAEA/CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - A J Cackett
- UKAEA/CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - C F Maggi
- UKAEA/CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - A G Meigs
- UKAEA/CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - K-D Zastrow
- UKAEA/CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - T M Biewer
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6169, USA
| | - D L Hillis
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6169, USA
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Hawkes NC, Delabie E, Menmuir S, Giroud C, Meigs AG, Conway NJ, Biewer TM, Hillis DL. Instrumentation for the upgrade to the JET core charge-exchange spectrometers. Rev Sci Instrum 2018; 89:10D113. [PMID: 30399852 DOI: 10.1063/1.5037639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 06/06/2018] [Indexed: 06/08/2023]
Abstract
Charge-exchange spectroscopy on JET has become particularly challenging with the introduction of the ITER-like wall. The line intensities are weaker and contaminated by many nuisance lines. We have therefore upgraded the instrumentation to improve throughput and allow the simultaneous measurement of impurity and fuel-ion charge exchange by splitting the light between two pairs of imaging spectrometers using dichroic beam splitters. Imaging instruments allow us to stack 11 × 1 mm diameter fibres on the entrance slits without cross talk. CCD cameras were chosen to have 512 × 512 pixels to allow frame transfer times <0.2 ms which with minimum exposure times of 5 ms give tolerable smearing even without a chopper. The image plane is optically demagnified 2:1 to match the sensor size of these cameras. Because the image plane of the spectrometer is tilted, the CCD must also be tilted to maintain focus over the spectrum (Scheimpflug condition). To avoid transverse keystoning (causing the vertical height of the spectra to change across the sensor), the configuration is furthermore designed to be telecentric by a suitable choice of the lens separation. The lens configuration is built almost entirely from commercial off-the-shelf components, which allowed it to be assembled and aligned relatively rapidly to meet the deadline for in-vessel calibration in the JET shutdown.
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Affiliation(s)
- N C Hawkes
- UKAEA/CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - E Delabie
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6169, USA
| | - S Menmuir
- UKAEA/CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - C Giroud
- UKAEA/CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - A G Meigs
- UKAEA/CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - N J Conway
- UKAEA/CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - T M Biewer
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6169, USA
| | - D L Hillis
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6169, USA
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Huber V, Huber A, Kinna D, Balboa I, Collins S, Conway N, Drewelow P, Maggi CF, Matthews GF, Meigs AG, Mertens P, Price M, Sergienko G, Silburn S, Wynn A, Zastrow KD. In-vessel calibration of the imaging diagnostics for the real-time protection of the JET ITER-like wall. Rev Sci Instrum 2016; 87:11D430. [PMID: 27910322 DOI: 10.1063/1.4959912] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The in situ absolute calibration of the JET real-time protection imaging system has been performed for the first time by means of radiometric light source placed inside the JET vessel and operated by remote handling. High accuracy of the calibration is confirmed by cross-validation of the near infrared (NIR) cameras against each other, with thermal IR cameras, and with the beryllium evaporator, which lead to successful protection of the JET first wall during the last campaign. The operation temperature ranges of NIR protection cameras for the materials used on JET are Be 650-1600 °C, W coating 600-1320 °C, and W 650-1500 °C.
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Affiliation(s)
- V Huber
- Forschungszentrum Jülich GmbH, Supercomputing Centre, 52425 Jülich, Germany
| | - A Huber
- Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung-Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), 52425 Jülich, Germany
| | - D Kinna
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - I Balboa
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - S Collins
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - N Conway
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - P Drewelow
- MPI für Plasmaphysik, Greifswald, Germany
| | - C F Maggi
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - G F Matthews
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - A G Meigs
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - Ph Mertens
- Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung-Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), 52425 Jülich, Germany
| | - M Price
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - G Sergienko
- Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung-Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), 52425 Jülich, Germany
| | - S Silburn
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - A Wynn
- York Plasma Institute, University of York, Heslington, York YO10 5DD, United Kingdom
| | - K-D Zastrow
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
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Huber V, Huber A, Kinna D, Balboa I, Collins S, Conway N, Drewelow P, Maggi CF, Matthews GF, Meigs AG, Mertens P, Price M, Sergienko G, Silburn S, Wynn A, Zastrow KD. Publisher's Note: "In-vessel calibration of the imaging diagnostics for the real-time protection of the JET ITER-like wall" [Rev. Sci. Instrum. 87, 11D430 (2016)]. Rev Sci Instrum 2016; 87:11F903. [PMID: 27910683 DOI: 10.1063/1.4962987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Affiliation(s)
- V Huber
- Forschungszentrum Jülich GmbH, Supercomputing Centre, 52425 Jülich, Germany
| | - A Huber
- Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung-Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), 52425 Jülich, Germany
| | - D Kinna
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - I Balboa
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - S Collins
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - N Conway
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - P Drewelow
- MPI für Plasmaphysik, Greifswald, Germany
| | - C F Maggi
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - G F Matthews
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - A G Meigs
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - Ph Mertens
- Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung-Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), 52425 Jülich, Germany
| | - M Price
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - G Sergienko
- Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung-Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), 52425 Jülich, Germany
| | - S Silburn
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - A Wynn
- York Plasma Institute, University of York, Heslington, York YO10 5DD, United Kingdom
| | - K-D Zastrow
- CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
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Lomanowski BA, Meigs AG, Conway NJ, Zastrow KD, Sharples RM, Heesterman P, Kinna D. Enhanced visible and near-infrared capabilities of the JET mirror-linked divertor spectroscopy system. Rev Sci Instrum 2014; 85:11E432. [PMID: 25430339 DOI: 10.1063/1.4893426] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The mirror-linked divertor spectroscopy diagnostic on JET has been upgraded with a new visible and near-infrared grating and filtered spectroscopy system. New capabilities include extended near-infrared coverage up to 1875 nm, capturing the hydrogen Paschen series, as well as a 2 kHz frame rate filtered imaging camera system for fast measurements of impurity (Be II) and deuterium Dα, Dβ, Dγ line emission in the outer divertor. The expanded system provides unique capabilities for studying spatially resolved divertor plasma dynamics at near-ELM resolved timescales as well as a test bed for feasibility assessment of near-infrared spectroscopy.
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Affiliation(s)
- B A Lomanowski
- Centre for Advanced Instrumentation, Department of Physics, Durham University, Durham DH1 3LE, United Kingdom
| | - A G Meigs
- EURATOM/CCFE Fusion Association, Culham Science Center, Abingdon OX14 3DB, United Kingdom
| | - N J Conway
- EURATOM/CCFE Fusion Association, Culham Science Center, Abingdon OX14 3DB, United Kingdom
| | - K-D Zastrow
- EURATOM/CCFE Fusion Association, Culham Science Center, Abingdon OX14 3DB, United Kingdom
| | - R M Sharples
- Centre for Advanced Instrumentation, Department of Physics, Durham University, Durham DH1 3LE, United Kingdom
| | - P Heesterman
- EURATOM/CCFE Fusion Association, Culham Science Center, Abingdon OX14 3DB, United Kingdom
| | - D Kinna
- EURATOM/CCFE Fusion Association, Culham Science Center, Abingdon OX14 3DB, United Kingdom
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Giroud C, Meigs AG, Negus CR, Zastrow KD, Biewer TM, Versloot TW. Impact of calibration technique on measurement accuracy for the JET core charge-exchange system. Rev Sci Instrum 2008; 79:10F525. [PMID: 19068535 DOI: 10.1063/1.2974806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The core charge-exchange diagnostic at the Joint European Torus (JET) provides measurements of the impurity ion temperature T(i), toroidal velocity V(phi), and impurity ion densities n(imp), across the whole minor radius. A contribution to the uncertainty of the measured quantities is the error resulting from the multi-Gaussian fit and photon statistics, usually quoted for each measured data. Absolute intensity calibration and especially alignment of the viewing directions can introduce an important systematic error. The technique adopted at JET to reduce this systematic contribution to the error is presented in this paper. The error in T(i), V(phi), and n(imp) is then discussed depending on their use.
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Affiliation(s)
- Carine Giroud
- EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon OX14 3DB, United Kingdom.
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