Speaker
Description
Detectors for photon science inherit concepts and technologies originally developed for vertex detectors in high-energy physics, driven by shared demands for high granularity, low noise, radiation tolerance, and fast frame rates. While the underlying sensors and readout chips show strong commonality, the experimental requirements differ fundamentally: unlike HEP vertex systems, photon-science detectors do not perform particle tracking due to the point-like absorption of X-rays, but instead focus on precise photon counting, imaging, spectroscopy, and operation across an extreme dynamic range. To meet these needs, photon-science instrumentation has developed advanced readout techniques to achieve both single-photon sensitivity and very high dynamic range. While single-photon counting revolutionized science at synchrotrons, charge-integrating detectors with dynamic gain switching are essential to achieve a dynamic range of 10^4 photons at X-ray Free Electron Lasers (XFELs). The rapid increase in source brilliance at synchrotrons and in repetition rate at X-ray free-electron lasers creates challenges analogous to those faced in collider experiments, particularly regarding data throughput, power density, and frame-rate capability.
From the sensor side, while planar silicon pixel sensors, as used in vertex detectors, are the standard choice, current research explores the customization of Low Gain Avalanche Detectors (LGADs) for soft X-ray detection, exploiting their internal gain to detect low-energy X-rays with improved signal-to-noise performance. At higher photon energies, compound semiconductor materials such as CdTe and GaAs can provide superior stopping power compared with silicon, and current research aims at developing materials with improved homogeneity and charge-collection properties.
The significant advances achieved in photon-science detector development can now provide valuable feedback to the vertex detector community, particularly through the characterization, the operational experience and the development of novel concepts and technologies, highlighting the importance of continued exchange and collaboration between the two communities.