SSAXI-Rocket delta-doped CMOS sensors

Current-generation solar observatories employ CCD image sensors to observe the Sun in the soft x-ray (SXR) and extreme ultraviolet (EUV) regimes. However, these observations are often compromised by pixel saturation and charge blooming in the CCD image sensors when observing large solar flares. To address these limitations, the Swift Solar Activity x-ray Imager Rocket (SSAXI-Rocket) program is developing CMOS image sensors (CIS) with low noise and high-speed readout (greater than 5Hz) for next-generation solar observatories. These CIS aim to enable the observation of large solar flares while significantly reducing the effects of pixel saturation and charge blooming. As a part of NASA’s 2024 solar flare sounding rocket campaign, the SSAXI-Rocket program demonstrated delta-doped CIS technology in a space environment by operating a novel camera as a sub-payload on board the High-Resolution Coronal Imager (Hi-C) sounding rocket. This paper describes the pre-launch laboratory tests performed with the SSAXI-Rocket CIS to characterize its linearity and soft x-ray spectral resolution.