Showing papers by "Michael Fiederle published in 2022"
TL;DR: In this article , the purity and crystallinity of solution-grown Cs 2 AgBiBr 6 single crystals with cubic Fm $$\overline{3}$$ were corroborated by powder XRD measurements, while the single crystal XRD patterns reveal the dominant {111} lattice planes parallel to the sample surfaces.
Abstract: Abstract Single crystals of lead-free halide double perovskite Cs 2 AgBiBr 6 sensor material manifest a remarkable potential for application in radiation detection and imaging. In this study, the purity and crystallinity of solution-grown Cs 2 AgBiBr 6 single crystals with cubic Fm $$\overline{3}$$ 3 ¯ m symmetry have been corroborated by powder XRD measurements, while the single crystal XRD patterns reveal the dominant {111} lattice planes parallel to the sample surfaces. A wider range of lower resistivity values (10 6 –10 9 Ωcm) was obtained from the I-V measurements compared to the 1.55 × 10 9 –6.65 × 10 10 Ωcm values from the van der Pauw method, which is typically higher for the Ag than for the carbon paint electrodes. Charge-carrier mobility values estimated from the SCLC method for the carbon paint-Cs 2 AgBiBr 6 (1.90–4.82 cm 2 V −1 s −1 ) and the Ag-Cs 2 AgBiBr 6 (0.58–4.54 cm 2 V −1 s −1 ) including the density of trap states (10 9 –10 10 cm −3 ) are comparable. Similar values of 1.89 cm 2 V −1 s −1 and 2.36 cm 2 V −1 s −1 are derived from the Hall effect measurements for a sample with carbon and Ag electrodes, respectively. The key electrical parameters including the X-ray photoresponse measurements indicate that the Cs 2 AgBiBr 6 samples synthesized in this study satisfy requirements for radiation sensors. Graphical abstract
6 citations
DOI•
TL;DR: The presented work describes the capabilities of a state-of-the-art spectroscopic photon-counting hybrid pixel detector for use in non-destructive testing, as a contaminant detector with potential uses in the food and pharmaceutical industries.
Abstract: The presented work describes the capabilities of a state-of-the-art spectroscopic photon-counting hybrid pixel detector for use in non-destructive testing, as a contaminant detector with potential uses in the food and pharmaceutical industries. A pharmaceutical hard capsule containing vitamin powder, contaminated with Steel (ST) and Tungsten (W) was prepared under controlled conditions. Both contaminants are distinguished from the powder by combining sub-pixel imaging with spectroscopic imaging analysis, made possible by the use of a 2 mm CdZnTe sensor coupled to a Timepix3 ASIC, operated in Time-over-Threshold and Time-of-Arrival mode. The sub-pixelization technique achieves a spatial resolution of 18.3 μm, with a maximum photon flux of 2.5× 106 photons/s· cm2. For the spectral analysis technique implemented, each energy bin image is energy-weighted, with weights optimally defined by considering the bin contrast and noise behavior, and combined to form an integrated-spectrum enhanced image with increased contaminant visibility. Contrast-to-Noise Ratio (CNR) for each contaminant type was used for performance assessment of the approach. A CNR increase of 106% above the reference unweighted-spectrum image was achieved for the ST contaminant, while the denser W contaminant showed a CNR increase of 80%. This means that the presented spectroscopic imaging technique is feasible for implementation in material visibility enhancement.
2 citations