Radiation hardness of the optical ribbon transmitter for the level-0 muon trigger

In this note we present the radiation hardness tests performed on the Agilent HFBR-772BP ribbon optical transmitter. It carries data between the muon detector and the muon trigger. We irradiated it with a proton beam of 250 MeV/c at the Paul Scherrer Institute in December 2003. The component works within its specification up to a total dose of ~15 kRad, corresponding to an integrated flux of 2.5 10^11 p/cm2. This limit is a factor 7 above the total dose expected for the muon frond-end electronics after 10 years of operation. The cross-section for single event upsets is equal to (4.5+-10.1)10^{-10} cm2 per single optical link. The corresponding inefficiency on the level-0 muon trigger is below 10^-10 and therefore negligible. This component match well the requirements of the trigger interface implemented in the muon fond-end electronics.