Absolute measurement of electron cyclotron emission using radiometer with SIS tunnel junction

Calibration of a W-band 8-channel heterodyne receiver for the measurement of the electron cyclotron emission (ECE) from W VII-A stellarator may be realized by adding a further channel with SIS mixer of high sensitivity as a reference in which ECE, attenuated to about 1000 K, is compared with the emission of well known blackbody sources at 77 K and 290 K.