Design and characterization of a prototype divertor viewing infrared video bolometer for NSTX-U

Journal Article · Tue Jul 12 00:00:00 EDT 2016 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4955487· OSTI ID:1368686

van Eden, G. G. ^[1]; Reinke, M. L. ^[2]; Peterson, B. J. ^[3]; Gray, T. K. ^[2]; Delgado-Aparicio, L. F. ^[4]; Jaworski, M. A. ^[4]; Lore, J. ^[2]; Mukai, K. ^[3]; Sano, R. ^[5]; Pandya, S. N. ^[6]; Morgan, T. W. ^[1]

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1. Dutch Institute for Fundamental Energy Research, AJ Eindhoven (The Netherlands)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
3. National Institute for Fusion Science, Toki (Japan)
4. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
5. National Institutes for Quantum and Radiological Science and Technology, Naka (Japan)
6. Institute for Plasma Research, Gujarat (India)

The InfraRed Video Bolometer (IRVB) is a powerful tool to measure radiated power in magnetically confined plasmas due to its ability to obtain 2D images of plasma emission using a technique that is compatible with the fusion nuclear environment. A prototype IRVB has been developed and installed on NSTX-U to view the lower divertor. The IRVB is a pinhole camera which images radiation from the plasma onto a 2.5 μm thick, 9 × 7 cm² Pt foil and monitors the resulting spatio-temporal temperature evolution using an IR camera. The power flux incident on the foil is calculated by solving the 2D+time heat diffusion equation, using the foil’s calibrated thermal properties. An optimized, high frame rate IRVB, is quantitatively compared to results from a resistive bolometer on the bench using a modulated 405 nm laser beam with variable power density and square wave modulation from 0.2 Hz to 250 Hz. The design of the NSTX-U system and benchtop characterization are presented where signal-to-noise ratios are assessed using three different IR cameras: FLIR A655sc, FLIR A6751sc, and SBF-161. The sensitivity of the IRVB equipped with the SBF-161 camera is found to be high enough to measure radiation features in the NSTX-U lower divertor as estimated using SOLPS modeling. Here, the optimized IRVB has a frame rate up to 50 Hz, high enough to distinguish radiation during edge-localized-modes (ELMs) from that between ELMs.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC02-09CH11466; AC05-00OR22725
• OSTI ID: 1368686
• Alternate ID(s): OSTI ID: 1412066; OSTI ID: 22596633
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 11 Vol. 87; ISSN 0034-6748; ISSN RSINAK
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

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