The ABCD3TA is a 128-channel ASIC with binary architecture for the readout of silicon strip particle detectors in the Semiconductor Tracker of the ATLAS experiment at the Large Hadron Collider (LHC). The chip comprises fast front-end and amplitude discriminator circuits using bipolar devices, a binary pipeline for first level trigger latency, a second level derandomising buffer and data compression circuitry based on CMOS devices. It has been designed and fabricated in a BiCMOS radiation resistant process. Extensive testing of the ABCD3TA chips assembled into detector modules show that the design meets the specifications and maintains the required performance after irradiation up to a total ionising dose of 10 Mrad and a 1-MeV neutron equivalent fluence of 2×1014 n/cm2, corresponding to 10 years of operation of the LHC at its design luminosity. Wafer screening and quality assurance procedures have been developed and implemented in large volume production to ensure that the chips assembled into modules meet the rigorous acceptance criteria

Dual resonance in a waveguide-coupled ring microresonator j iříč t y r o ký 1, * , i va n r i c h t e r 2 a n d m i l a nš iň o r 2 Abstract. Eigenmodes of an isolated circular ring or disk microresonator are degenerate because of its rotational symmetry. Coupling of the microresonator to a straight bus guide breaks the rotational symmetry of the device. As a result, two slightly different resonant frequencies occur. While this effect is known in microring lasers, it is usually neglected in microring-based filters and add-drop de/multiplexers for telecom applications. Resonant frequency splitting does not follow from the usual 'optical circuit' analysis of the microring devices in which the coupling between the bus guide and ring is described by the 2 × 2 coupling matrix. It is shown here that the full 4 × 4 scattering matrix that takes into account also the back-reflections in the coupling region has to be used in order to include this effect into consideration. The magnitude of the resonant frequency splitting due to coupling to the bus guides in small high-contrast structures is estimated by two-dimensional numerical modelling based on bi-directional mode expansion and FDTD algorithms.

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In a spectroscopic study of non-irradiated and proton-irradiated silicon diodes, the detectors were illuminated from the front side and from the rear side by various alpha particle sources (mainly ThC') and by monoenergetic protons with energies from 1.0 to 2.5 MeV. Their response characteristics have been studied as a function of the incoming particle energy and the applied bias voltage. The charge collection eciency was determined as a function of uence.