Speaker
Description
Inverse Low-Gain Avalanche Diode (iLGAD) sensors with a thin entrance window (TEW) have emerged as a promising technology for extending the applications of hybrid pixel detectors into the soft X-ray regime. The latest iteration of our TEW technology achieves a quantum efficiency exceeding 85% at 250 eV, comparable to state-of-the-art soft X-ray detectors, and the internal charge amplification of the iLGAD enables reliable discrimination of low-energy photon signals, reaching a signal-to-noise-ratio (SNR) greater than 5 down to 400 eV. In this contribution, we present the recent characterization results from iLGAD sensors bonded to the charge-integrating JUNGFRAU ASIC, with a focus on performance parameters relevant for both synchrotron and free-electron laser applications.
We report systematic measurements of sensor leakage current, gain stability, and equivalent noise charge for different pixel and gain layer designs at various temperatures and sensor bias voltages. Spatial-resolution studies are presented for detectors employing rectangular pixels, which exploit charge sharing to achieve sub-micrometer interpolation accuracy in one dimension, ultimately aiming to provide a high-performance detector option for Resonant Inelastic X-ray Scattering (RIXS). Furthermore, we discuss the spectral response of the current iLGAD generation, including challenges of the inverse LGAD configuration, such as the depth-dependent multiplication factor and reduced quantum efficiency at grazing incidence. Based on these characterization results, we conclude with an outlook on the new iLGAD R&D batch currently in fabrication and expected by mid-2026, which is designed to provide substantially improved quantum efficiency and higher intrinsic gain.