Hi, Peter
Thanks for your reply.According to my understanding of your reply, there is no incidence angle correction, here is one of the PPT (from David Small, Nuno Miranda, Erich Meier ),pay attention to the formula in the red box, I think that the sin(incidence angle) term is just like the term sin（θ），if you wang to get Gamma naught (not Sigma naught)just replace it with tan(incidence angle).Right? I’m not sure whether i understand it correctly.
In addition, the effect from incidence angle shouldn’t be ignored when comparing the sigma0 of a feature at a different incidence angle. So, it is necessary to correct the incident angle after radiation calibration.Of course ,just a coarse correction.
Chen