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- ItemA new concept for temporal gating of synchrotron X-ray pulses(Chester : IUCr, 2021) Schmidt, D.; Bauer, R.; Chung, S.; Novikov, D.; Sander, M.; Pudell, J.E.; Herzog, M.; Pfuetzenreuter, D.; Schwarzkopf, J.; Chernikov, R.; Gaal, P.A new concept for temporal gating of synchrotron X-ray pulses based on laser-induced thermal transient gratings is presented. First experimental tests of the concept yield a diffraction efficiency of 0.18%; however, the calculations indicate a theoretical efficiency and contrast of >30% and 10−5, respectively. The full efficiency of the pulse picker has not been reached yet due to a long-range thermal deformation of the sample after absorption of the excitation laser. This method can be implemented in a broad spectral range (100 eV to 20 keV) and is only minimally invasive to an existing setup.
- ItemReciprocal space slicing: A time-efficient approach to femtosecond x-ray diffraction(Melville, NY : AIP Publishing LLC, 2021) Zeuschner, S.P.; Mattern, M.; Pudell, J.-E.; von Reppert, A.; Rössle, M.; Leitenberger, W.; Schwarzkopf, J.; Boschker, J.E.; Herzog, M.; Bargheer, M.An experimental technique that allows faster assessment of out-of-plane strain dynamics of thin film heterostructures via x-ray diffraction is presented. In contrast to conventional high-speed reciprocal space-mapping setups, our approach reduces the measurement time drastically due to a fixed measurement geometry with a position-sensitive detector. This means that neither the incident (ω) nor the exit ( 2θ ) diffraction angle is scanned during the strain assessment via x-ray diffraction. Shifts of diffraction peaks on the fixed x-ray area detector originate from an out-of-plane strain within the sample. Quantitative strain assessment requires the determination of a factor relating the observed shift to the change in the reciprocal lattice vector. The factor depends only on the widths of the peak along certain directions in reciprocal space, the diffraction angle of the studied reflection, and the resolution of the instrumental setup. We provide a full theoretical explanation and exemplify the concept with picosecond strain dynamics of a thin layer of NbO2.