Results on photon and neutron irradiation of semitransparent amorphous-silicon sensors

Semitransparent amorphous-silicon sensors are basic elements for laser 2D position reconstruction in the CMS multipoint alignment link system. Some of the sensors have to work in a very hard radiation environment. Two different sensor types have been irradiated with ⁶⁰Co photons (up to 100 kGy) and fast neutrons (up to 10 ¹⁵ cm^-2), and the subsequent change in their performance has been measured.