Evaluation on radiant characteristics of a honeycombed surface by Monte Carlo simulation

Blackbody (BB) cavities as standard radiation sources are used in calibration for various infrared (IR) instruments in IR detection, imaging, material emissivity measuring etc. A surface pitted with cell-like mini cavities as honeycombs whose radiant characteristics is evaluated by Monte Carlo method (MCM) is applied to develop a new surface BB. To improve the precision of MCM, make it more reliable, three requisite factors are considered. First, set up correct physical model in which the radiation of a surface comes from light emitting points across the surface consistently. Second, the uniformity of random number generators are investigated, which is the precondition for the MCM simulation. Third, to perform simulating with tremendous sampling number, after all light points and their rays are tracked, the statistical results become stable, fluctuate slightly, which increase the exactitude of MCM. To implement MCM simulation, every ray of the IR lights is tracked, the position of a light point, the direction of a ray, the state that if the ray is absorbed or reflected at a reflecting point etc. are all regarded as random variables which are sampled by random number according to their probability distribution. The effective emissivity of the surface is evaluated statistically via tracking numerous rays which involves setting up the ray equation, and coordinates transformation etc. The relationships between the accuracy of computation results and simulating model, sampling method, uniformity of pseudo-random number, and sampling number have been discussed. The results show the surface with honeycombs can provide a consistent radiation near to be a diffuse emitter even the material of the surface including spectral components, and the MCM simulating results provide the criteria for surface BB design.