08/09/2023
Diamond sensor measures the position of individual X-ray flashes
Using a special diamond sensor, researchers at European XFEL have succeeded in precisely measuring the position of the extremely intense and short X-ray flashes generated by the facility-in a pulse-resolved way at megahertz rate and with minimal disturbance of the X-ray beam.
To successfully carry out experiments at X-ray free-electron lasers such as the European XFEL, scientists need to know the intensity, spectrum, and position of the X-ray beam as accurately as possible. What's more, these parameters have to be measured in a least-invasive manner that affects the beam properties as little as possible.
As the X-ray flashes generated by the facility are extremely intense and short, with durations in the femtosecond range, these measurements are very challenging to realize. Present X-ray imaging systems, for example, deliver accurate beam shape and position information, but only at 10 hertz, i.e. ten times per second and thus averaged over several hundred pulses.
Using a special diamond sensor, scientists at European XFEL have now succeeded in measuring the horizontal and vertical position of the facility's X-ray beam non-invasively, at a repetition rate of 2.25 megahertz - i.e. on a pulse-by-pulse basis - with a measurement uncertainty of about 5 micrometres for a beam size of 500 micrometres, corresponding to an uncertainty of about 1%.
"The pulse-resolved beam position measurements delivered by our sensor will provide valuable input for experiments carried out at the European XFEL, taking their precision to a whole new level," emphasizes first author Tuba Çonka Yιldιz from the X-Ray Photon Diagnostics group. The team of researchers from European XFEL and CEA-List at Université Paris-Saclay in France have published their breakthrough in the journal Optica.
Source: European XFEL GmbH