Thermal characteristics of foils for an imaging bolometer

The IR imaging video bolometer is an imaging bolometer which provides the intensity and distribution of plasma radiation. The sensitivity of the IR imaging bolometer is dependent on the properties of the bolometer foil. An evaluation of the thermal characteristics of various materials and thicknesses of the bolometer foil provides information on the sensitivity which is useful to choose the best foil material. We irradiated foils of various materials and thicknesses with a He-Ne laser (wavelength 633 nm), and measured the change in temperature distribution with an IR camera. As for foil materials,W, Ta, Au and Pt were employed. The foils were blackened either on both sides or on one side by graphite. For the same material foil, the temperature rise in the singleside blackened foil was always greater than the double-side blackened foil. For the double blacken foil, Ta had the largest temperature rise among foils with the same thickness. Pt had the shortest time constant for the temperature rise/decayamong foils except Au. In consideration of the attenuation thickness versus photon energy of each material, the Pt foil was the most suitable for the bolometer among the evaluated materials. (author)