Method of calculating radiation

摘要

The invention relates to a method, a storage medium and a computer system for calculating radiation. Conventionally, a coarse mesh having the same size, i.e., a calculation cell, was used regardless to whether the location is near or remote from radiation elements such as calculation cells and wall face elements. Therefore, it took very long calculation time to calculate an energy exchange between a remote location covered by a coarse mesh and a noted cell. Further, there were many non-influential cells for calculation in a location remote from a noted radiation element for radiation calculation, thus making the calculation accuracy low. The present invention provides a method of calculating radiation comprising a measure for completing the calculation rapidly while keeping the calculation accuracy high. Near at a calculation cell from which radiation energy is emitted or at a calculation cell P into which radiation energy is absorbed, a small (level 0) cell is used, and at a remote location from the calculation cell P, a large (level n) cell formed by combining plural small cells is used. Further, a largest calculation cell which comes into the field of view angle DELTA OMEGA covered by a ray is selected. As a result, the accuracy of the radiation calculation is enhanced, the calculation time is shortened and the amount of memory necessary for the calculation can be reduced.