Speaker
Description
The advent of fourth-generation synchrotrons, such as the Diamond II upgrade, offers unprecedented flux increases of 10–100×, reaching up to $10^{12}$ photons/s/mm² over a wide energy range (20–100 keV). Fully leveraging these photon fluxes and high X-ray energies necessitates readout chips with exceptional frame rates and dynamic ranges, alongside the use of high-Z sensor materials. To address these requirements, STFC has developed DynamiX, a novel test structure using a two-stage charge cancellation circuit fabricated on a 65 nm CMOS process. This design achieves a dynamic range spanning 0.2 ph/pix/frame to $3 \times 10^{11}$ ph/s/mm² at 30 keV. The ASIC features a 16 × 16-pixel array on a 110 μm pitch, which is hybridized to a 2-mm-thick Redlen high-flux cadmium zinc telluride (HF-CdZnTe) sensor. Operating at 533,000 fps, the device outputs data via a 14 Gbps serializer, with frames assembled and stored using a custom DAQ system. Performance evaluations were conducted at the Diamond Light Source B16 beamline using a monochromatic X-ray beam with varied beam sizes and energies. Results include measurements with sub-pixel beam for single-photon detection, and an X-ray tube was used for linearity studies up to $2 \times 10^{10}$ ph/s/mm² (30 keV equivalent). These results feed directly into the design of the scaled-up 192x144-pixel version of the ASIC.
| Workshop topics | Detector systems |
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