Radiation-hard optoelectronic data readout for the ATLAS SCT

The ATLAS experiment is currently in the final pre-production design phase to allow timely installation at the CERN Large Hadron Collider in 2005. The sub-systems closest to the interaction point the tracking detectors, will be subject to significant total radiation dose at high flux. Optical data transmission has been chosen for the Pixel and SemiConductor Tracker to both deliver timing and control information to the detector modules and transmit tracking data to the remote counting room. Of considerable concern is the radiation hardness, both transient and total dose, of not just the optoelectronic components but also the driver/receiver electronics. In this paper we report on total dose radiation testing of the VCSEL driver and photodiode receiver ASICs designed using a range of techniques in a nominally radiation-soft process. Both ASICs will be shown to be tolerant to a total gamma dose of 100 kGy and a total neutron fluence (1 MeV equiv.) of 2*10/sup 14/ n/cm/sup 2/, as required for this system. Single-event upset (SEU) studies have also been carried out using a high-energy pion beam, showing the system to be sufficiently robust to SEU at an ATLAS-like particle flux. (9 refs).