Simulations have been done assuming a misplacement of the WAB of 2mm in x and y direction (z is the direction of the main beam) and 1 degree rotation around x and y axis.

The assumptions of shift and rotation are based on the maximum tolerable misplacement of any baffle in KAGRA.

Result: no important impact on the sensitivity of the interferometer has been found.

However, the effect on the power due to the rotation turns out to be 10000 times stronger than due to the shifting!