2016 Volume 11 Pages 2402101
The InfraRed imaging Video Bolometer (IRVB) provides absolutely calibrated images of the plasma radiation. In this paper we present the design of four imaging bolometers viewing divertor and non divertor regions of Wendelstein7-X (W7-X). This design assumes a 640 × 480 pixel, 30 fps, 100 mK, IR camera imaging each IRVB foil. The bolometer cameras consist of a 9 cm × 7 cm × 2 µm thick Pt foils blackened with graphite, which are located distances ranging 6cm to 8cm from a 4.3 mm × 4.3 mm aperture. The 8 cm × 6 cm central section of the foil is divided into 24 × 18 IRVB channels each consisting of 504 IR camera pixels. Using a previously derived expression, the noise equivalent power of the IRVB is calculated as 109 µW/cm2. Assuming 5 MW of radiated power uniformly emanating from the 30 m3 plasma, the signal level is estimated as ranging from 4.5 to 8.1 mW/cm2 giving signal to noise ratios between 42 and 74.
