The invention discloses a
black body cavity
radiation source which comprises a liquid
thermostat, a
black body cavity, a temperature controller, a pump and a standard
thermometer. The
black body cavity and the temperature controller are installed in the liquid
thermostat, the black
body cavity comprises a cavity inner shell and a cavity outer shell, and the inner wall of the cavity inner shell and the inner wall of the cavity outer shell are coated with black
diffuse reflection coatings. The cavity inner shell with the front end being a
conical cavity and the rear end being a columniform cavity is coaxially installed in the liquid
thermostat, and the cavity outer shell with the same shape as that of the cavity inner shell is installed outside the cavity inner shell to form an equally spaced hollow interlayer. The end surface of the cavity inner shell is connected with the outer wall of the liquid thermostat, a
conical cavity opening of the cavity outer shell is communicated with a pump shell, the pump shell is communicated with the liquid thermostat through the opening, an
impeller in the pump shell is connected with a motor through a pump shaft, the standard
thermometer is arranged in the hollow interlayer, and openings are equally distributed on the cavity outer shell. In the invention, the cavity outer shell and the pump are additionally arranged to enable
liquid medium in the thermostat to flow in a circulating way in the hollow interlayer, thereby improving the temperature distribution of a black
body cavity, enabling the black
body cavity to have the characteristic of isothermy and further enhancing the
emissivity of the black body cavity.