Infrared thermography in metallic environments of WEST and ASDEX Upgrade

Design, justification, and prototyping of the visible and infrared wide angle viewing system diagnostic for ITER equatorial port 12

The ITER equatorial visible and infrared Wide Angle Viewing System (WAVS) will play a major role in the protection of plasma facing components by providing surface temperature measurements of these components. It will also image the plasma emission in the visible range. The WAVS is composed of 15 lines of sight located in four Equatorial Ports (EPs) 3, 9, 12, and 17. Its development is being carried out by the Consortium constituted by CEA, CIEMAT, INTA, and Bertin Technologies, within grant contracts financed by F4E. In the EP12, the in-vessel and ex-vessel components of the WAVS are at their final design phase. This article presents an overview of the opto-mechanical design of the WAVS in the EP12 presented at the final design review.

Active thermo-reflectometry for absolute temperature measurement by infrared thermography on specular materials

Knowledge of material emissivity maps and their true temperatures is of great interest for contactless process monitoring and control with infrared cameras when strong heat transfer and temperature change are involved. This approach is always followed by emissivity or reflections issues. In this work, we describe the development of a contactless infrared imaging technique based on the pyro-reflectometry approach and a specular model of the material reflection in order to overcome emissivities and reflections problems. This approach enables in situ and real-time identification of emissivity fields and autocalibration of the radiative intensity leaving the sample by using a black body equivalent ratio. This is done to obtain the absolute temperature field of any specular material using the infrared wavelength. The presented set up works for both camera and pyrometer regardless of the spectral range. The proposed method is evaluated at room temperature with several heterogeneous samples covering a large range of emissivity values. From these emissivity fields, raw and heterogeneous measured radiative fluxes are transformed into complete absolute temperature fields.

Indirect Thermographic Temperature Measurement of a Power-Rectifying Diode Die

This article concerns the indirect thermographic temperature measurement of a die of the semiconductor diode D00-250-10. The article shows how the goal was achieved. The methodology of selecting the point at which thermographic measurements of the temperature of the diode cases were performed is discussed. The method of thermographic measurement of the case temperature and the measuring system used is described. The method of simulations making it possible to obtain the die’s temperature on the basis of thermographic casing temperature measurement is presented. In order to enable a better understanding of the discussed issues, the construction of the diode used and the heat flow equation are described. As a result of the work carried out, the point at which the temperature is closest to the die temperature was indicated on the diode case. It is shown that the difference between the casing temperature and the die temperature does not exceed 2 °C at the point indicated. An indirect measurement of the die’s temperature is carried out for different values of the power dissipated on the die.

Bidirectional reflectance measurement of tungsten samples to assess reflection model in WEST tokamak

This paper presents the measurement of the bidirectional reflectance distribution function of tungsten (W) samples and the resulting reflection models in the nuclear fusion device WEST (tokamak). For this, an experimental gonio-spectrophotometer was developed to fully characterize the material's optical and thermal-radiative properties of metallic samples with different roughnesses. Ray-tracing photonic simulation was then carried out to predict the photon behavior in a fully metallic environment as a function of reflectance measurement. Low emissivity (0.1 at 4 μm) and highly specular reflectance (fitting with a Gaussian distribution around the specular direction with a small width lower than 10°) are found for W samples. These measurements have been used as input for the photonic simulation, and the resulting synthetic image reproduced the reflection features well on the upper divertor, detected in WEST infrared experimental images.