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Title: Preliminary design of a tangentially viewing imaging bolometer for NSTX-U

Abstract

The InfraRed imaging Video Bolometer measures plasma radiated power images using a thin metal foil. Two different designs with a tangential view of NSTX-U are made assuming a 640 x 480 (1280 x 1024) pixel, 30 (105) fps, 50 (20) mK, IR camera imaging the 9 cm x 9 cm x 2 μm Pt foil. The foil is divided into 40 x 40 (64 x 64) IRVB channels. This gives a spatial resolution of 3.4 (2.2) cm on the machine mid-plane. The noise equivalent power density of the IRVB is given as 113 (46) μW/cm 2 for a time resolution of 33 (20) ms. Synthetic images derived from SOLPS data using the IRVB geometry show peak signal levels ranging from ~0.8 - ~80 (~0.36 - ~26) mW/cm 2.

Authors:
 [1];  [2];  [3];  [3];  [4];  [3];  [1];  [3]; ORCiD logo [5];  [4]
  1. National Inst. for Fusion Science, Toki (Japan); Graduate Univ. for Advance Studies (SOKENDAI), Toki (Japan)
  2. National Inst. for Quantum and Radiological Science and Technology, Naka, Ibaraki (Japan)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  5. Dutch Foundation for Fundamental Research on Matter (FOM), Eindhoven (The Netherlands). Dutch Inst. for Fundamental Energy Research (DIFFER)
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE; National Institute for Fusion Science (Japan); National Institutes for Natural Sciences (Japan)
OSTI Identifier:
1368172
Grant/Contract Number:
AC02-09CH11466; AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 87; Journal Issue: 11; Journal ID: ISSN 0034-6748
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION

Citation Formats

Peterson, B. J., Sano, R., Reinke, M. L., Canik, J. M., Delgado-Aparicio, L. F., Lore, J. D., Mukai, K., Gray, T. K., van Eden, G. G., and Jaworski, M. A.. Preliminary design of a tangentially viewing imaging bolometer for NSTX-U. United States: N. p., 2016. Web. doi:10.1063/1.4955278.
Peterson, B. J., Sano, R., Reinke, M. L., Canik, J. M., Delgado-Aparicio, L. F., Lore, J. D., Mukai, K., Gray, T. K., van Eden, G. G., & Jaworski, M. A.. Preliminary design of a tangentially viewing imaging bolometer for NSTX-U. United States. doi:10.1063/1.4955278.
Peterson, B. J., Sano, R., Reinke, M. L., Canik, J. M., Delgado-Aparicio, L. F., Lore, J. D., Mukai, K., Gray, T. K., van Eden, G. G., and Jaworski, M. A.. 2016. "Preliminary design of a tangentially viewing imaging bolometer for NSTX-U". United States. doi:10.1063/1.4955278. https://www.osti.gov/servlets/purl/1368172.
@article{osti_1368172,
title = {Preliminary design of a tangentially viewing imaging bolometer for NSTX-U},
author = {Peterson, B. J. and Sano, R. and Reinke, M. L. and Canik, J. M. and Delgado-Aparicio, L. F. and Lore, J. D. and Mukai, K. and Gray, T. K. and van Eden, G. G. and Jaworski, M. A.},
abstractNote = {The InfraRed imaging Video Bolometer measures plasma radiated power images using a thin metal foil. Two different designs with a tangential view of NSTX-U are made assuming a 640 x 480 (1280 x 1024) pixel, 30 (105) fps, 50 (20) mK, IR camera imaging the 9 cm x 9 cm x 2 μm Pt foil. The foil is divided into 40 x 40 (64 x 64) IRVB channels. This gives a spatial resolution of 3.4 (2.2) cm on the machine mid-plane. The noise equivalent power density of the IRVB is given as 113 (46) μW/cm2 for a time resolution of 33 (20) ms. Synthetic images derived from SOLPS data using the IRVB geometry show peak signal levels ranging from ~0.8 - ~80 (~0.36 - ~26) mW/cm2.},
doi = {10.1063/1.4955278},
journal = {Review of Scientific Instruments},
number = 11,
volume = 87,
place = {United States},
year = 2016,
month = 8
}

Journal Article:
Free Publicly Available Full Text
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  • The infrared imaging video bolometer (IRVB) measures plasma radiated power images using a thin metal foil. Two different designs with a tangential view of NSTX-U are made assuming a 640 × 480 (1280 × 1024) pixel, 30 (105) fps, 50 (20) mK, IR camera imaging the 9 cm × 9 cm × 2 μm Pt foil. The foil is divided into 40 × 40 (64 × 64) IRVB channels. This gives a spatial resolution of 3.4 (2.2) cm on the machine mid-plane. The noise equivalent power density of the IRVB is given as 113 (46) μW/cm{sup 2} for a timemore » resolution of 33 (20) ms. Synthetic images derived from Scrape Off Layer Plasma Simulation data using the IRVB geometry show peak signal levels ranging from ∼0.8 to ∼80 (∼0.36 to ∼26) mW/cm{sup 2}.« less
  • 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 cm 2 Pt foil and monitors the resulting spatio-temporal temperature evolution using an IR camera. The power flux incident on the foil is calculated by solvingmore » 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.« less
  • 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 cm{sup 2} Pt foil and monitors the resulting spatio-temporal temperature evolution using an IR camera. The power flux incident on the foil is calculated by solvingmore » 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. 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.« less
  • A second fast ion D-alpha (FIDA) installation is planned at NSTX to complement the present perpendicular viewing FIDA diagnostics. Following the present diagnostic scheme, the new diagnostic will consist of two instruments: a spectroscopic diagnostic that measures fast ion spectra and profiles at 16 radial points with 5-10 ms resolution and a system that uses a band pass filter and photomultiplier to measure changes in FIDA light with 50 kHz sampling rate. The new pair of FIDA instruments will view the heating beams tangentially. The viewing geometry minimizes spectral contamination by beam emission or edge sources of background emission. Themore » improved velocity-space resolution will provide detailed information about neutral-beam current drive and about fast ion acceleration and transport by injected radio frequency waves and plasma instabilities.« less
  • Two 32-channel side-viewing soft x-ray diode arrays will be installed on PBX-M which will provide profile information in the horizontal and vertical directions with a time resolution up to 1 ..mu..s. The information from these arrays can be reconstructed to provide a high time-resolution poloidal emission profile using a maximum-entropy-based technique which incorporates the reconstructed profile from a tangentially viewing soft x-ray pinhole camera. The pinhole camera provides lower time-resolution (about 5 ms) shape information which has been reconstructed with the assumption of toroidal symmetry. The pinhole camera information supplements the information from the diode arrays, allowing a reconstruction whichmore » can resolve MHD fluctuations of the equilibrium profile. The pinhole camera information need only be a better approximation to the real emission profile than the assumption of a flat profile since the algorithm uses it as a first-order solution which is perturbed by the information from the diode arrays. The algorithm can also explicitly include the bean-shaped PBX-M vacuum vessel and the vignetting of some detectors by the pusher coil.« less