**Flat-cone geometry in D10 (J. Rodríguez-Carvajal)**
The banana detector of radius R is supposed to be fixed to the arm along the **x**_{L} axis and has the possibility to be rotated by an angle *µ* around **x**_{D}=**x**_{L}. We defined a detector frame having the same orientation as the laboratory system when *µ*=0. Notice that for D10 we use a Busing-Levy L-system with the **z**_{L}-axis pointing downwards. For a general position of the detector the relation between the L and D systems is given by the matrix providing the components of a vector in the D system when their components in L are known:
A diffracted beam impinging the detector is shown in the following figure. We can deduce the relations between the angles (*µ*, *α*) of the detector and the angles (*γ*, *ν*) of the diffracted beam from the geometry shown in the figure.
From the figure on the left side one can see that:
OO’=OP=R, OS = R cos**, SP = R sin**.
So, in the detector system the vector |