Speaker
Description
The European Synchrotron Radiation Facility builds a new ultra-bright synchrotron source, the ESRF-EBS [1] in the period 2015-2022, which will deliver an X-ray beam with performances multiplied by 100 in terms of brightness and coherence. In this context, diffraction and X-ray imaging experiments will benefit from X-ray detectors covering a large dynamic range (above 16 bits), large field of view (at least 10cmx10cm), while operating at high X-ray energies (between 30keV and 100keV) and high frame rates (above 100 frames per second). In the case of X-ray diffraction, indirect detection scheme using a scintillator to absorb and convert X-ray photons into light is important at high X-ray energies (starting from 30keV). Concerning X-ray imaging, indirect detection is the only scheme able to cope with the huge intensities of the X-ray beams while providing down to micrometer spatial resolution. Therefore, we plan to develop structured scintillators optimized for synchrotron radiation applications. The scintillating screen will be a key component, as it will determine the final X-ray absorption efficiency, speed, precision as well as stability of the detection system under high energy and intense X-ray flux.
In this context, we will present the evaluation of structured scintillators for synchrotron X-ray applications up to X-ray energies of 100keV. At these X-ray energies, the structuration of the scintillating screen is important to guide the emitted scintillation light and thus avoid the degradation of the Line Spread Function due to the spread of optical photons within the bulk of the scintillator. The properties of the scintillating screen will be focused on: spatial resolution below 50µm, low afterglow to solve at least 16bit dynamic range, high thermal and radiation stability, X-ray absorption >80% in the range 30keV-100keV, decay time <500µs, easily four-side buttable to cover large areas >10cmx10cm.
The presentation will be focused on experimental measurements of spatial resolution and afterglow. For the tests, we coupled the scintillating screens via a Fiber Optics face plate with 3µm diameter fibers to a 6.5µm pixel size sCMOS Andor Zyla 5.5 camera. The screens were exposed to a bright (flux >1010 ph/s/mm2) monochromatic X-ray beam at the ESRF BM05 beamline [2].
The spatial resolution measurements are compared with simulations using the Mantis-based simulation tool installed, modified and recompiled at the ESRF [ 3].
