Reference orbit

The recombination/separation dipoles D1 and D2 are defined as main dipoles and therefore they define the reference orbit. For this reason their action on the beam trajectory cannot be seen via the X and Y variables since they are defined with respect to the reference orbit. The definition of reference orbit in the experimental insertions can be found here. Of course, this does not apply to the orbit correctors which are defined as below and their actions on the beam can be seen in the variable X and Y.