Consideration of signal to noise ratio for an imaging bolometer for ITER

An infrared imaging video bolometer (IRVB) is proposed for ITER having a tangential view of the entire ITER cross section. For the initial estimate of the signal level, a 840 m plasma is assumed to uniformly radiate 67.3 MW. A more detailed estimate of the signal strength is provided by synthetic images based on radiation data from SOLPS and SANCO models for the edge and core plasma, respectively. The Pt foil used as the radiation absorber would have the dimensions of 7 × 9 cm and a thickness of 16 μm that will stop 95% of the radiated power. Two different InSb based IR cameras having a sensitivity of 15 mK are considered for measuring the temperature rise of the foil due to the radiation. The first has 1280 × 1024 pixel and a frame rate of 105 fps. The second has 640 × 512 pixel and a frame rate of 1000 fps. The resulting IRVBs have 40 × 30 pixel , 10 ms time resolution, and a signal to noise ratio (SNR) of 17 and 20 × 15 pixel , 3 ms time resolution, and a SNR of 35, respectively. The synthetic image data give SNRs of 30 and 59, respectively.