arXiv subjects

X. F. D. Stragier

Publications and source records attributed to X. F. D. Stragier.

3 recordsLinked to original sources

arXiv2025

First x-rays from a compact and tunable LINAC-based Compton scattering source

In this paper, we present the first measurements of x-rays produced with a compact, narrowband, and tunable inverse Compton scattering-based x-ray source, developed at Eindhoven University of Technology. A flux of $1.2 \cdot 10^3$ photons per shot was measured, in agreement with simulations. Using a high-resolution spectral camera, we show that the photon energy can be tuned continuously from 5.8~keV to 10.7~keV with a bandwidth of 4\%. The measured x-ray pulse length was in the picosecond range. Additionally, we show that the source allows full control over the x-ray polarization control. By optimizing experimental parameters, implementing improvements to the setup and further conditioning of the accelerator structure, a brilliance of $10^{12}$ photons/(s $\times$ mrad$^2$ $\times$ mm${^{2}}$ $\times$ 0.1\% BW) can be achieved, with photon energies up to 40 keV. Because the complete electron beamline fits on a single optical table, it is suitable as an in-house x-ray source for university laboratories, industrial production lines, museums, and hospitals.

physics.acc-ph↗

arXiv2019

Gigahertz repetition rate thermionic electron gun concept

We present a novel concept for the generation of gigahertz repetition rate high brightness electron bunches. A custom design 100 kV thermionic gun provides a continuous electron beam, with the current determined by the filament size and temperature. A 1 GHz rectangular RF cavity deflects the beam across a knife-edge, creating a pulsed beam. Adding a higher harmonic mode to this cavity results in a flattened magnetic field profile which increases the duty cycle to 30%. Finally, a compression cavity induces a negative longitudinal velocity-time chirp in a bunch, initiating ballistic compression. Adding a higher harmonic mode to this cavity increases the linearity of this chirp and thus decreases the final bunch length. Charged particle simulations show that with a 0.15 mm radius LaB6 filament held at 1760 K, this method can create 279 fs, 3.0 pC electron bunches with a radial rms core emittance of 0.089 mm mrad at a repetition rate of 1 GHz.

physics.acc-ph↗

arXiv2017

Theory and particle tracking simulations of a resonant radiofrequency deflection cavity in TM$_{110}$ mode for ultrafast electron microscopy

We present a theoretical description of resonant radiofrequency (RF) deflecting cavities in TM$_{110}$ mode as dynamic optical elements for ultrafast electron microscopy. We first derive the optical transfer matrix of an ideal pillbox cavity and use a Courant-Snyder formalism to calculate the 6D phase space propagation of a Gaussian electron distribution through the cavity. We derive closed, analytic expressions for the increase in transverse emittance and energy spread of the electron distribution. We demonstrate that for the special case of a beam focused in the center of the cavity, the low emittance and low energy spread of a high quality beam can be maintained, which allows high-repetition rate, ultrafast electron microscopy with 100 fs temporal resolution combined with the atomic resolution of a high-end TEM. This is confirmed by charged particle tracking simulations using a realistic cavity geometry, including fringe fields at the cavity entrance and exit apertures.

physics.acc-ph↗