FIELD: instrumentation. SUBSTANCE: thermo-capillary convection in thin layer of clear liquid on absorbing non-heat-conducting backing induced by thermal action of measured radiation of laser is used in process of measurement. Radiation power is determined with the use of device visualizing diameter of interference picture formed as result of reflection of portion of radiation inducing convection from free surface of liquid deformed by thermo-capillary convection. Thermo-capillary convection is excited in sealed metal coveted with clear window which is partially filled with chemically inactive, low- viscous and non-volatile clear liquid. Coveted carries radiator ribs for thermostating liquid under temperature of air surrounding it. Blackened non-heat-conducting membrane located in center of symmetric platform floating in liquid that ensures exact horizontal position of layer of liquid on membrane submerged in liquid to specified depth is employed as element absorbing radiation. There is provided possibility of discrete change of thickness of layer of liquid by means of two sets of ferromagnetic ballast washers. Washers of different sets have different masses. EFFECT: simplified measurement process, exclusion of effect of background radiation. 4 cl, 5 dwg
