MHz frame rate hard X-ray phase-contrast imaging using synchrotron radiation.

Margie P Olbinado,Jean-Louis Gelet,Adrian Mancuso,Alexander Rack,Rita Graceffa,Pierre Lhuissier,Mario Scheel,Patrik Vagovic,John Morse,Joachim Schulz,Tokushi Sato,Xavier Just

doi:10.1364/oe.25.013857

Abstract

Third generation synchrotron light sources offer high photon flux, partial spatial coherence, and ~10-10 s pulse widths. These enable hard X-ray phase-contrast imaging (XPCI) with single-bunch temporal resolutions. In this work, we exploited the MHz repetition rates of synchrotron X-ray pulses combined with indirect X-ray detection to demonstrate the potential of XPCI with millions of frames per second multiple-frame recording. This allows for the visualization of aperiodic or stochastic transient processes which are impossible to be realized using single-shot or stroboscopic XPCI. We present observations of various phenomena, such as crack tip propagation in glass, shock wave propagation in water and explosion during electric arc ignition, which evolve in the order of km/s (µm/ns).

Highlights

Hard X-ray radiography based on attenuation-contrast has been the main approach employed to investigate transient processes, which evolve on timescales governed by material sound speeds in the order of km/s, in optically opaque objects
The multiple-frame recordings that were achieved are very relevant to dynamic studies that cannot be performed with a single-shot X-ray phase-contrast imaging (XPCI) achieved using synchrotron radiation and laser-based backlighters
We have demonstrated the high potential of the MHz repetition rates of high-brilliance synchrotron X-ray pulses for UHS-XPCI by visualizing aperiodic and stochastic transient processes which are impossible to be visualized using just single-shot XPCI such as crack tip propagation, shock wave propagation in liquid and plasma explosions

Summary

Introduction

Hard X-ray radiography based on attenuation-contrast has been the main approach employed to investigate transient processes, which evolve on timescales governed by material sound speeds in the order of km/s (μm/ns), in optically opaque objects. Propagation-based XPCI [5,6,7] is mostly applied for real-time imaging of transient dynamics as it does not require any specialized optical elements that reduce X-ray photon flux It has been adapted as a diagnostic for laser-induced-shock studies using laser-based backlighters, which generate 10−12 s width X-rays per flash, with limited sensitivity due to spatial incoherence and low spectral brightness of the source [8,9]. The MHz repetition rates of high-brilliance synchrotron X-ray pulses present enormous potential for UHS-XPCI It allows the visualization of aperiodic and stochastic transient processes which are impossible to be visualized using just single-shot XPCI such as crack tip propagation, shock wave propagation in liquids or porous materials, high-speed jetting and spallation, and plasma explosions. The high temporal and spatial resolutions were achieved by carefully considering image lag, scintillator decay, spectral matching between the scintillator emission and image sensor spectral responsivity, scintillator thickness and numerical aperture of the coupling optical lens

X-ray source

X-ray detector

X-ray phase-contrast imaging

Findings

Discussion

Summary