Estimates of foil thickness, signal, noise, and nuclear heating of imaging bolometers for ITER

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Peterson, B.J. and Nishitani, T. and Reichle, R. and Munechika, K. and O'Mullane, M.G. and Mukai, K. (2022) Estimates of foil thickness, signal, noise, and nuclear heating of imaging bolometers for ITER. Journal of Instrumentation, 17 (6). P06034. ISSN 1748-0221 (https://doi.org/10.1088/1748-0221/17/06/p06034)

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Abstract

Imaging bolometers have been studied for ITER to serve as a complementary diagnostic to the resistive bolometers for the measurement of radiated power. Two tangentially viewing InfraRed imaging Video Bolometers (IRVB) could be proposed for an ITER equatorial port, one having a view of the entire plasma cross-section (core viewing) and one tilted down 43 degrees from the horizontal to view the divertor (divertor viewing). The IRVBs have 7 cm (horizontal) by 9 cm (vertical) Pt sensor foils, 6 mm × 6 mm apertures, 15 × 20 pixels and focal lengths of 7.8 cm and 21 cm, respectively. Using SANCO and SOLPS models for a 840 m3 plasma radiating 67.3 MW, synthetic images from the IRVBs are calculated to estimate the maximum signal strengths to be 246 W/m2 and 62 W/m2, respectively. We propagate the X-ray energy spectra from the models through the synthetic diagnostics to give the photon energy spectrum for each IRVB pixel, which are used to calculate the fraction of the power absorbed by the foil as a function of foil thickness. Using a criteria of >95% absorbed power fraction, we selected foil thicknesses of 30 μm and 10 μm, respectively. We used these thicknesses and assumed IR systems having 105 fps, 1024×1280 pixels and sensitivities of 15 mK, to calculate the IRVB sensitivities of 3.19 W/m2 and 1.05 W/m2, and signal to noise ratios of 77 and 59, respectively. Using the Monte Carlo Nuclear Particle code we calculated for the core viewing IRVB the foil heating by neutrons to be 1.0 W/m2 and by gammas to be 117 W/m2. This indicates that countermeasures may be needed to remove the nuclear heating signal.

ORCID iDs

Peterson, B.J., Nishitani, T., Reichle, R., Munechika, K., O'Mullane, M.G. ORCID logoORCID: https://orcid.org/0000-0002-2160-4546 and Mukai, K.;
  • Item type:Article
    ID code:81298
    Dates:
    Date
    Event
    27 June 2022
    Published
    16 May 2022
    Accepted
    15 February 2022
    Submitted
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:29 Jun 2022 14:00
    Last modified:20 Nov 2024 07:43
    URI:https://strathprints.strath.ac.uk/id/eprint/81298
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