Electro-photonic Detector Units

Pixel detectors provide the coordinates where charge is released due to the interaction of a passing particle or an X-ray photon with the sensor material. They can also provide additional information such as event time, cluster size, or topology. The primary limitation these detectors face is the speed of electrical data transmission. Advanced readout techniques, such as event-driven methods, may be used but the data bus onto which multiple pixel buffers are connected restricts readout speeds to O(100) Mpixels/s, even when using parallel buses for AER. Although used in some cases, frequency domain multiplexing for encoding individual bits or pixel addresses in the electrical domain is impractical due to the properties of interconnects in integrated circuits, including attenuation and the complexity of high-quality resonators. Conversely, in the photonic domain, optical domain multiplexing in a single waveguide is feasible and the resonators used for modulation are compact.

Earlier work has demonstrated a large-scale integrated nanophotonic phased array for visible wavelengths in a silicon nitride (SiN) platform. This array consists of 32×32 optical antenna elements and can project complex intensity patterns directly from the photonic integrated circuit in the far field at a wavelength of 635 nm. Related technological advancements in SiN include waveguides fabricated in a state-of-the-art 300-mm CMOS foundry and the development of active and passive photonic devices. We will take advantage of these advances by developing a highly-segmented,vertically integrated pixelated radiation detector with direct optical readout.

Deliverables

Design of photonic readout integrated circuit: Small photonic design in a pixelated form.

Design of hardware emulator of pixelated detector readout and integration with photonic counterpart: Small ASIC in a pixelated form matching photonic readout for integration.

Design of MAPS detector and integration and integration with photonic counterpart: Small MAPS detector matching photonic readout for integration.