Black-body radiation source with conductive cavity heated by induction

摘要

The conductive cavity (2) is machined in a bar of tungsten and is enclosed by thermal insulation (4) to reduce the effect on the surrounding 3 mm thick transparent quartz crucible (8). The assembly is placed in an evacuated quartz cylinder (10) around which the helical induction coil (6) is wound. The mass of the cavity is sufficient to smooth out fluctuations in power from the heater, which is supplied with alternating current at about 4 kHz. The insulation consists of agglomerated grains of zirconium or thorium oxide. An alternative embodiment has a graphite bar with graphite foam insulation.