https://indico.ihep.ac.cn/event/11423/contribution/11/material/slides/0.pdf The JC-134 paper describes the topic of Develop of low-energy X-ray detectors using LGAD sensor. This is the summary:

• Hybrid detectors have not yet been applied to low-energy X-rays due to their noise.
• However, LGAD maybe a good candidate to detect low-energy X-ray due to its internal gain.
• LGAD microstrip sensors fabricated by FBK were wire-bonded to single-photon- counting and charge-integrating readout electronics developed at the PSI in order to characterize their performance for soft X-ray detection.
• The results demonstrate the possibility of extending the minimal detectable energy of X-rays for PC and the single-photon resolution for CI microstrip detectors down to or below 2 keV.