First pump–probe–probe hard X-ray diffraction experiments with a 2D hybrid pixel detector developed at the SOLEIL synchrotron

Abstract

A new photon‐counting camera based on hybrid pixel technology has been developed at the SOLEIL synchrotron, making it possible to implement pump–probe–probe hard X‐ray diffraction experiments for the first time. This application relies on two specific advantages of the UFXC32k readout chip, namely its high frame rate (50 kHz) and its high linear count rate (2.6 × 106 photons s−1 pixel−1). The project involved the conception and realization of the chips and detector carrier board, the data acquisition system, the server with its specific software, as well as the mechanical and cooling systems. This article reports on in‐laboratory validation tests of the new detector, as well as on tests performed at the CRISTAL beamline within the targeted experimental conditions. A benchmark experiment was successfully performed, showing the advantages of the pump–probe–probe scheme in correcting for drifts of the experimental conditions.

Temporal and spatial tracking of ultrafast light-induced strain and polarization modulation in a ferroelectric thin film

“…The pump beam irradiates nearly entirely the sample surface, while the probe x-ray beam is made at least twice smaller (maximum size of the x-ray footprint on sample: 90 μm by 500 μm). The various Bragg reflections studied were imaged using a photon-counting camera that was newly developed at SOLEIL, which enables simultaneous measurements at positive and negative pump-probe delays ( 55 ). Bragg reflections with high Miller indices (such as 403 m and 530 m ) were chosen to increase the sensitivity of the measurement to the light-induced strain.…”

EIGER2 hybrid-photon-counting X-ray detectors for advanced synchrotron diffraction experiments

“…Modern HPC detectors have the potential to exploit the pulsed nature of synchrotron sources without the need for additional beamline optics. Electronic gating allows individual X-ray pulses from a single bunch of the storage ring bunch structure to be isolated (Ejdrup et al, 2009;Kraft et al, 2009;Burian et al, 2020;Bachiller-Perea et al, 2020;Schmidt et al, 2021). This approach allows for time-resolved experiments that are not limited by the readout speed of the detector, but only by the duration of the X-ray pulse, which is usually < 100 ps (Burian et al, 2020;Nakaye et al, 2021).…”

X-ray detectors at Diamond Light Source, evolution and future challenges

“…For these reasons it is difficult to use the current generation of detectors in time resolved experiments if the dynamic is much faster than one millisecond. However, if the experiment is cyclic, such as in pump and probe experiments, it is possible to exploit the logic gate shown in figure 2 to gate the detector with an external signal and enable the acquisition for a very short time interval which can go down to 100 ns or less [17]. As the gate signal delay is moved with respect to a time reference (for instance a laser pulse used as a pump) the dynamic of the experiment is reconstructed with time resolution corresponding to the gate duration.…”