The prototype DynamiX camera system - a high-frame-rate high-dynamic-range hard X-ray integrating detector for...

The development of fourth-generation synchrotrons, including the Diamond-II upgrade, promises 10-100× flux increases, reaching up to 10¹² photons s^-1 mm^-2 at the detector, across a broad range of energies from 20 to 100 keV. To exploit fully these impressive photon fluxes and high X-ray energies, readout chips must achieve high frame rates and dynamic ranges, while the use of high-Z sensor materials is essential. To address these challenges, the UK's Science and Technology Facilities Council has developed DynamiX, a test structure for a novel two-stage charge cancellation circuit on a 65 nm CMOS process with a dynamic range from single photon(s) per pixel per frame to >9000 photons per pixel per frame (10¹¹-10¹² photons s^-1 mm^-2) at 20 keV photon energy. The application-specific integrated circuit has 16 ×16 pixels on 110 µm pitch and is hybridized with 2 mm thick Redlen high-flux cadmium zinc telluride (HF-CdZnTe). Data are read out at 534000 frames per second over a 14 Gbps serialiser and frames are assembled and saved with a custom data acquisition system. Measurements were made on the Diamond Light Source (DLS) B16 Test Beamline using monochromatic X-ray beams of different sizes and energies to evaluate the detector performance. A sub-pixel beam of size ∼60 µm × ∼15 µm was used to probe pixels to measure single photons with a noise performance of σ = 5.7 ± 0.1 keV. These single photons are used to calibrate the test pulse and pixel cancellation packet sizes. The linearity of the detector response under increasing flux was measured from <1 photon per pixel per frame to ∼10⁹ photons s^-1 mm^-2 at 20 keV with an r.m.s. linearity of 6.2%. A polychromatic X-ray set was used to reach higher fluxes of ∼3 × 10¹⁰ photons s^-1 mm^-2 (20 keV equivalent), yielding an r.m.s. linearity of 3.2%. Finally, the full sensor area was used to image a rotating slitted disc at 534000 frames per second.