FAST PYROBOLOMETERS FOR MEASUREMENTS OF PLASMA HEAT FLUXES AND RADIATION LOSSES IN THE MADISON SYMMETRICAL TORUS REVERSED-FIELD PINCH

Two types of fast bolometers are described for the plasma energy transport study in the Madison symmetric torus plasma confinement device. Both types use pyrocrystals of LiTaO3 or LiNbO3 as the sensors. One type is used for measurements of the radiated heat losses and is situated at the vacuum shell inner surface. Another type is insertable in the plasma and measures the plasma particle heat flux. The frequency response of the bolometers is measured to be in the 150-200 kHz range. The range of the measured power fluxes is 0.1 W/cm2-10 kW/cm2 and can be adjusted by changing the size of the entrance aperture. The lower limit is determined by the amplifier noise and the frequency bandwidth, the higher limit by destruction of the bolometer sensor.