Extending the energy range of Hybrid Photon Counting (HPC) detectors will allow scientist to realise ambitious projects. The new EIGER2 detector series is compatible with cadmium telluride (CdTe) sensors. This sensor material efficiently absorbs X-rays with energies above 20 keV. Combined with high dynamic range, high speed, and the absence of afterglow, HPC detectors with CdTe sensors pave the way for dynamic studies at high energies.
Experimental setup at beamline ID27 at ESRF. The insets show representative diffraction patters from CeO2 powder (left) and an enstatite crystal (right).
We have now collected first data with an EIGER2 X CdTe 1M prototype at a synchrotron. Mohamed Mezouar and his staff helped us collect test data at the high-pressure beamline ID27 at ESRF. In two days, we recorded more than 70 data sets at 33 keV and obtained high-quality data at a variety of exposure settings.
The high sensitivity of the CdTe sensor at high energies is important for fast and dynamic measurements. We recorded diffraction patterns from CeO2 powder in only a few milliseconds. "This is a 15-fold improvement compared to the previous detector used for dynamic measurements," says Mezouar. The strong reflections from the sample holder, a diamond anvil cell, did not spoil the measurement or data analysis. The sharp point spread function of EIGER2 X CdTe ensures that even the strongest reflections are spatially contained.
Single-crystal diffraction of enstatite in a diamond anvil cell. Slice through the reciprocal lattice of enstatite at k = 0 (left). Refined structure of enstatite (right).
Single-crystal diffraction of the mineral enstatite gave good results with an Rint of 8%, despite the low completeness of the data. Volodymyr Svitlyk, beamline scientist at ID27, was instrumental in the success of the measurements. He solved the structure from the collected data and refined the model with anisotropic displacement parameters. "With an increased effective area, data quality would be improved," predicts Svitlyk and concludes that "the tested EIGER2 X CdTe 1M detector is well adapted for single-crystal diffraction experiments at high energies".
DECTRIS presented the full CdTe detector series at SRI 2018 in Taipei. First detectors will ship in early 2020. To guide your beamline upgrade, contact us now for more information.