Improvement of infrared imaging video bolometer for application to deuterium experiment on the large helical device

Mukai, K.; Abe, Ryohei; Peterson, B.J.; Takayama, S.

doi:10.1063/1.5038947

Cited by 5 publications

(4 citation statements)

References 11 publications

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“…Blackening of the foil is also an important aspect for IRVB. In this case a vacuum evaporated carbon coating has been developed which significantly enhanced reproducibility and uniformity of the calibration process so that uncertainties less than about 10 % could be achieved [31,32].…”

Section: Spectral Sensitivity Of Bolometer Sensorsmentioning

confidence: 99%

“…To tackle the challenging calibration of the IRVB system an improved approach has been presented recently [32]. It is based on a removable unit which can be attached to the IRVB viewing system and uses a visible laser of known power to illuminate individual pixels of the detection foil.…”

Section: Irvb Concept For Itermentioning

confidence: 99%

“…Combined with the improved carbon coatings (see section 4.2) calibration errors could be suppressed to less than about 10 %. Furthermore, the application of this system during a deuterium campaign on LHD demonstrated a good resilience against neutrons and plasma radiation from both, plasma discharges and glow discharges [32].…”

Section: Irvb Concept For Itermentioning

confidence: 99%

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Bolometer developments in diagnostics for magnetic confinement fusion

et al. 2019

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The plasma radiation is an essential part of the power balance in current and future magnetic confinement fusion experiments and gives crucial insight for the challenges of power exhaust and divertor detachment as well as valuable information to understand plasma instabilities and transport effects. It is typically measured using various types of bolometers. Present day experimental devices, both the tokamak and stellarator, make use of metal resistor bolometers and infrared imaging video bolometers (IRVB), depending on the main focus of the respective measurement. The well-established sensor for absolutely calibrated measurements is the metal resistor bolometer. AXUV diodes, often used in conjunction with bolometers, are ideal for observing fast transient events in a plasma due to their very short response times, but their sensitivity varies significantly over the full radiation spectrum and degrades over their lifetime. In cases where many lines-of-sight are needed to observe radiation profiles in complex geometries IRVB offers the ability to integrate high channel counts in rather narrow installation volumes. Fibre-optic bolometers are a new development promising measurements immune to electro-magnetic interference. These diagnostic concepts are presented as well as their pros and cons.For future devices like ITER and DEMO, R&D efforts are required to adapt sensors and diagnostic schemes to the harsh nuclear environment. An overview will be given over the activities for sensor development and integration challenges, which may also be relevant for long pulse operation in present experiments. K: Photon detectors for UV, visible and IR photons (vacuum), Nuclear instruments and methods for hot plasma diagnostics, bolometer, ITER, DEMO

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Section: Spectral Sensitivity Of Bolometer Sensorsmentioning

confidence: 99%

Section: Irvb Concept For Itermentioning

confidence: 99%

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Bolometer developments in diagnostics for magnetic confinement fusion

et al. 2019

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“…However, it is too costly, especially for radiation profile measurement with a number of channels. On the other hand, InfraRed imaging Video Bolometer (IRVB) can realize a multi-dimensional measurement using only a foil absorber and an infrared (IR) camera [5][6][7][8][9]. Preliminary results of an IRVB on GAMMA10/PDX suggested that the sensitivity of the IRVB should be improved to realize the sensitivity comparable to that of the measurement on the Large Helical Device, LHD.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity improvement of infrared imaging video bolometer for divertor plasma measurement

Mukai

Peterson

Ezumi

et al. 2021

Review of Scientific Instruments

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The sensitivity of an infrared imaging video bolometer (IRVB) was improved for the measurement of relatively low energy plasma radiation from the viewpoint of the metal foil absorber material. The photon energy of the radiation was considered up to 1 keV for the divertor plasma measurement. The thickness of the foil absorber was evaluated not only for conventional heavy elements, e.g., platinum, but also for light elements by the relation between the photon energy and attenuation length and by mechanical strength. A heat-transfer calculation using ANSYS suggested that light elements with practical foil thickness provide a higher temperature rise of the foil absorber compared with heavier elements with practical foil thickness. The maximum of the temperature rise was evaluated using He–Ne laser irradiation onto absorber samples. The material dependence of the temperature rise has a similar tendency between calculations and experiments. Experimentally, the sensitivity of the IRVB improved from 280 to 110 µW/cm2 using titanium with 1 µm thickness compared with conventional platinum with 2.5 µm thickness. Consequently, the signal-to-noise ratio of the IRVB could be improved from 2.8 to 9.1.

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