the standard deviation of all the errors in the terms of the characteristics
of the concentrator.
The normal distribution of the radiation at the focal point Eq. (8)
is given by Abramowitz and Stegun [25]; however, there are more
exact descriptions of the error distribution [21]. It is not necessary
to include additional parameters that are not included in the present
study. When considering the STSC, the maximum error of the
approximation of the polynomial I(a) is a continuous function
z(x), unlike the model proposed by Stine and Harrigan [22].