LSO-Based Single Crystal Film Scintillator for Synchrotron-Based Hard X-Ray Micro-Imaging

X-ray detector systems are powerful tools: in combination with tomographic methods they provide volumetric data of samples in a non-destructive manner which is of high interest for, e.g., biology, medicine or materials research. The detector able to provide images with submicrometer spatial resolution frequently consists of a scintillator screen, light microscopy optics and a digital camera. Here, the scintillator converts the X-rays into a visible light image which is projected onto the camera by the light optics. In order to perform high resolution imaging Single Crystal Film (SCF) scintillators 1μ mto 30μ mthin are required due to the limited depth of focus of the microscopy optics. Thin SCFs can be obtained via liquid phase epitaxy (LPE). A drawback is that a detector working with SCFs suffers from low efficiency (2% at 50 keV) owing to their limited thickness. The detective quantum efficiency (DQE) is here mainly limited by the low absorption of X-rays and the light yield in the thin scintillator layer. Performances, i.e absorption, light yield, afterglow of operational systems at the European Synchrotron Radiation Facility (ESRF) using YAG:Ce (Y ₃ Al ₅ O ₁₂:Ce), LAG:Eu (Lu ₃ Al ₅ O ₁₂:Eu) and GGG:Eu (Gd ₃ Ga ₅ O₁₂:Eu) scintillatorswill be presented and compared to new LSO:Tb (Lu ₂ SiO ₅:Tb) scintillators developed in the framework of an European project,. A new concept to improve the efficiency of detection in the 20 keV – 40 keV energy range with 1μ mspatial resolution will be presented. This concept based on multilayer scintillators is realised by the LPE process as well. First results will be illustrated with X-ray images and will demonstrate the absorption efficiency improvement of the X-ray detector. The expected performance is 7 times better than the LAG-based scintillators.