Operation of thin metal foil bolometer for radiation loss measurement in a toroidal plasma on Heliotron E

A thin metal foil bolometric detector for time-resolved radiation loss measurements in the Heliotron E toroidal plasma confining experiment is described. The bolometer consists of a 10 or 50 gm thick stainless-steel radiation absorber, an insulation layer and a nickel resistor pattern. The bolometric detector, its electronics, the construction of the array and installation under vacuum and high-temperature conditions in toroidal plasma devices are reported. The physical principles of detection of the wavelength integrated total radiative loss from plasmas are described. The detector array consists of wide-angle bolometers to monitor the time-resolved total radiative loss power and a recently tested 17-channel bolometer array camera to measure the profiles of radiative loss. Typical radiative loss measurements in helical plasmas on Heliotron E with ECRH and NBI heating are presented.