Dish shading algorithm

Dear all,
could you give me some reference for the reciprocal shading calculation in Dish Stirling solar field?
SAM's guide tells that the implemented model is different from Fraser's one but it does not give any other information.

Thanks in advance.

All the best

The Fraser thesis describes the Osborn shading model in an appendix. SAM's implementation is similar to that, but not identical. Here is the FORTRAN source code for the TRNSYS modules described in the Fraser thesis: ZIP 32 KB . SAM's implementation is adapted from this code, so you can explore how the shading model is implemented in those files.
Best regards,

Paul.