Imaging performances of an in-house compact high spatial resolution X-ray detector based on Electrowetting Liquid Lens

The performances of compact and efficient new X-ray detector for hard X-ray synchrotron applications have been evaluated. This detector consists of an indirect detector based on a thin scintillator coupled to a CMOS digital camera by an infinity corrected microscope objective and an electrowetting liquid lens. Using such an optical combination focuses the image by applying a simple stabilized current without any motorization, while keeping the same imaging performances. The optical properties in term of Modulation Transfer Function (MTF) and time stability have been measured at a visible wavelength and compared with a classical microscope. An X-ray microscope camera based on this proposed optical combination with a magnification of ten (10x) has been assembled and tested on a hard X-ray beamline at the SOLEIL synchrotron. A spatial resolution of 415 1p/mm (line of 1.2 mu m wide) and an X-ray area gain of 2.2 ADU/ph have been measured for a 12 keV energy beam. Results have been compared with those obtained with a classical microscope and also with a theoretical model. The compact X-ray microscope proposed can fit close to the sample in order to measure the X-ray incident beam size and intensity. Coupled with high performance scientific CMOS camera, this system can be used, for example, in a very restricted space on X-ray microscopy tomography beamline environment for 3D X-ray micro-tomography reconstruction.