Large area hybrid detectors based on Medipix3RX: commissioning and characterization at Sirius beamlines

Abstract

Hybrid pixel detectors are inherently modular and typically operate at relative low noise levels, while providing high spatial resolution, easing the assembling of large area detectors. This report summarizes the procedures and results regarding the characterization studies performed on the Medipix3RX ASIC based detector, known as PIMEGA, which was developed and is deployed at Sirius synchrotron facility at the Brazilian Synchrotron Light Laboratory. They consist of modular constructions that reach up to 170 × 170 mm2 of active area, with 300 µm thick silicon sensors, and pixel size of 55 × 55 µm2. We investigated the spatial and energy resolutions, structural noise properties, and count-rate linearity up to large fluxes from the synchrotron beamlines. The Modulation Transfer Function presents a considerably slow decay rate as a function of the spatial frequency, reaching 30% at 10.5 lp/mm, for an operation with a threshold setting equivalent to half of the incident energy. We have also found that the energy resolutions of the two highest gain modes are around 15% for 17.5 keV incident photons. In particular, we have found that, for a noise-suppressing set of configurations, the detector presents a dead time of 460 ± 10 ns. Additionally, the pile-up effect leads to a 10% loss of linearity at input fluxes of 2.3 × 105 photons/pixel.s. These results open the possibility for operating these devices with in-depth knowledge of their performance, allowing various scientific experiments, such as X-ray diffraction, computed controlled tomography, and ptychography.

Characterization of Hybrid Pixel Detector With CdTe Sensor

“…In this work, the MTF was measured with the standard slanted-edge technique [22] by recording images of a slanted tungsten edge positioned close to the detector surface at approximately 2.5 degrees to a sensor row, as shown in Figure 4b and similarly performed previously for PIMEGA Si detector [23]. In order to determine the MTF, images of the radiopaque tungsten object with the slanted edge were acquired using the X-ray tube set at 70 kV and 50 mAs at a distance of 1.6 m, which corresponds to a radiation dose of 284.47 μGy.…”

Large area hybrid detectors at Sirius: Operation threshold optimization for Medipix3RX

“…Hybrid detectors are widely used for large area radiation imaging at synchrotron facilities. Among the reasons that make this kind of device appealing are the low noise level, energy discrimination, and relatively high count-rate capabilities, as recently described by our group on the PIMEGA detectors [1].…”

Patching-based deep-learning model for the inpainting of Bragg coherent diffraction patterns affected by detector gaps

“…Technological solutions are on the horizon, e.g. the PIMEGA or through-silicon via technology (Campanelli et al, 2023), but the majority of pixel detectors available at the time of writing have gaps between active areas.…”