In situ quantification of plasma facing surface conditions in the uragan-2M torsatron

The method and device has been developed and used for operative estimation of impurity level, outgassing rate and number of impurity gases molecular layers, on the surface of the Uragan-2M (U-2M) vacuum chamber walls. It is based on the thermal desorption of gases into a vacuum vessel from the surface of a special stainless steel probe during its heating up to temperature of 300ºC. The investigations were carried out of an outgassing rate and number of molecular layers on the probe surface in situ in the torsatron Uragan-2M. Decrease released gas amount from the surface by more than two orders of magnitude was recorded after Uragan-2M vacuum chamber VHF/RF discharge cleaning in various regimes and pumping. The method had been also tested in the regime of the measurements of hydrogen gas release retained in the probe before and after impact of RF plasma pulse discharges in work regime.