A low-noise small-pixel hybrid CMOS detector for future x-ray observatories
Abstract
To meet the requirements of future high-throughput and high spatial resolution Lynx-like X-ray observatories, the Pennsylvania State University High-Energy Astrophysics Detector and Instrumentation Lab, in collaboration with Teledyne Imaging Sensors (TIS), has developed a next-generation small-pixel soft X-ray hybrid CMOS detector (HCD). The Small-Pixel-1024 is an HCD with a 1024×1024 grid of 12.5-micron pitch pixels, featuring a high-gain capacitive transimpedance amplifier and in-pixel correlated double sampling. The Small-Pixel-1024 can operate in full-frame and windowed modes, with full-frame readout speeds up to 149 frames/s and windowed readout rates exceeding 1 kHz. For development efforts, two separate pixel designs were created using different feedback capacitance circuit schemes to restore pixel full-well post pixel reset, allowing for X-ray sensitivity up to 20 keV. The ‘A0’ pixels use a capacitor that can be enabled or disabled and retains heritage from a prototype small-pixel detector. The ‘A1’ pixels use the more traditional CMOS scheme of a complementary passgate that cannot be disabled. Here, we report on the methods and results for the characterization and optimization of the Small-Pixel-1024 dark current, read noise, gain variation, and energy resolution, including a comparison between the two pixel types.