Based on the Monte-Carlo method

cylindrical blackbody cavity model is established

effective emissivity of blackbody cavity model is calculated

analyze impact of different cavity geometry structure

emissivity of cavity materials

distance from detector and other factors on black body cavity effective emissivity

and compare with the results obtained by finite element analysis method. The results show that the results obtained by MonteCarlo method are in accord with that by finite element analysis method

namely the longer diameter is larger

the aperture ratio is smaller

the cavity material emissivity is larger

while blackbody cavity has larger effective emissivity.