Optical alignment system for the ZEUS micro vertex detector

The electron–proton scattering experiment ZEUS will be equipped with a silicon vertex detector in preparation for the upgrade of the HERA collider. An optical alignment system for the vertex detector is being developed. The alignment system measures the position of the vertex detector with respect to the outer tracking detector as well as the shape of the vertex detector using semi-transparent amorphous-silicon sensors and diode lasers. A test of the alignment system was performed using the support structures of the vertex detector. The results are presented and discussed.