At the heart of this advancement lies the Hadamard transform - a mathematical technique traditionally used in spectroscopy and imaging. The researchers adapted this method to the time domain, enabling the encoding of X-ray probe pulses into complex, patterned sequences. These sequences allow for the reconstruction of a sample’s transient response with high temporal resolution and improved signal-to-noise ratio, even when using fewer photons.
To implement this sophisticated timing control, the team deployed the WaveGate pulse picker. This solid-state device uses a controlled deformation of piezoelectric crystals to diffract X-ray pulses with nanosecond precision. By synchronizing the WaveGate with the X-ray source and by using external triggers, researchers can generate customizable pulse patterns that follow Hadamard matrices—mathematical constructs that ensure efficient and accurate data acquisition.
The benefits of this approach were demonstrated in two test measurements at the PETRA III synchrotron in Hamburg. In one, the team tracked the motion of a translation stage using Debye-Scherrer diffraction, successfully reconstructing its position over time despite motion blur. In another, they monitored the micromechanical oscillation of a thin silicon nitride membrane excited by nanosecond lang laser pulses. The Hadamard method enabled the detection of subtle structural changes that would have been missed using conventional pump-probe techniques.
The WaveGate pulse picker, which enables the generation of Hadamard-encoded X-ray pulse sequences, was developed by the IKZ - Desy start-up TXproducts. Together with IKZ and DESY, a research center of the Helmholtz Association, TXproducts operates a test and demonstration facility for the development of novel X-ray photonics components. The facility will be used by IKZ researchers for time-resolved material science studies.
Contact
Leibniz-Institut für Kristallzüchtung (IKZ)
Crystalline Materials for Photonics
Group X-Ray Optics
Dr. Peter Gaal
Phone +49 (0) 30 / 246 499 614
Email carsten.hartmannikz-berlin.de
