Calibration and sensitivity of the infrared imaging video bolometer

The infrared (IR) imaging video bolometer (IRVB) is an imaging bolometer which uses a large (9?cm×9?cm) thin (1 μm) gold foil and an IR camera to provide images of radiation from the plasma. Calibration of the IRVB using a lamp has been performed to compensate for any nonuniformities in the foil’s thickness and its thermal properties due to blackening of the foil with graphite to improve the IR emissivity. This calibration revealed close to expected values for the calibration coefficient proportional to the product of the thermal conductivity and the foil thickness in the central region of the foil, while these values were anomalously high near the foil edge. The calibration coefficient proportional to the thermal diffusivity is a factor of 2 smaller than the expected value at the center and drops further at the edge of the foil. Using a derived expression for the IRVB noise equivalent power, a sensitivity comparison shows the IRVB using current IR technologies to be ? 200 times less sensitive than an equivalent conventional resistive bolometer operating under ideal conditions