An electron beam of very high energy (50–250 MeV) can potentially produce a more favourable radiotherapy dose distribution compared to a state-of-the-art photon based radiotherapy technique. To produce an electron beam of sufficiently high energy to allow for a long penetration depth (several cm), very large accelerating structures are needed when using conventional radio-frequency technology, which may not be possible due to economical or spatial constraints. In this paper, we show transport and focusing of laser wakefield accelerated electron beams with a maximum energy of 160 MeV using electromagnetic quadrupole magnets in a point-to-point imaging configuration, yielding a spatial uncertainty of less than 0.1 mm, a total charge variation below $$1 \%$$ 1 % and a focal spot of $$2.3 \times 2.6\;{\text {mm}}^2$$ 2.3 × 2.6 mm 2 . The electron beam was focused to control the depth dose distribution and to improve the dose conformality inside a phantom of cast acrylic slabs and radiochromic film. The phantom was irradiated from 36 different angles to obtain a dose distribution mimicking a stereotactic radiotherapy treatment, with a peak fractional dose of 2.72 Gy and a total maximum dose of 65 Gy. This was achieved with realistic constraints, including 23 cm of propagation through air before any dose deposition in the phantom.

Many state-of-the-art applications for linear accelerators, such as free-electron lasers (FELs) and plasmawakefield accelerators (PWFAs), require small normalized emittances, and PWFAs in particular are very sensitive to transverse slice offsets along the beam. Dispersive systems, such as bunch compressors, can cause different chromatic aberrations, one of which yields transverse slice offsets. In this paper, we show a design approach to double-achromat bunch compressors which greatly reduces different chromatic aberrations and mitigates coherent synchrotron radiation effects.

In this letter we report for the first time the possibility of visualizing an atomizing spray by simultaneously recording X-ray absorption and 2photon laser-induced fluorescence imaging. This unique illumination/detection scheme was made possible thanks to the use of soft X-rays emitted from a laser-driven X-ray source. An 800 mJ laser pulse of 38 fs duration is used to generate an X-ray beam with up to 4 × 10 8 photons ranging from 1 to 10 keV, allowing projection radiography of water jets generated by an automotive port fuel injector. In addition, a fraction of the laser pulse (∼ 10 mJ) is employed to form a light sheet and to induce 2-photon fluorescence in a dye added to the water. The resulting high-contrast fluorescence images provide fine details of the spray structure, with reduced blur from multiple light scattering, while the integrated liquid mass is extracted from the X-ray radiography. In this proof-of-principle we show that the combination of these two highly complementary techniques, both in the visible and in the soft X-ray regime, is very promising for the future characterization of challenging spray, as well as for further understanding the physics of liquid atomization.

Highly collimated betatron radiation from a laser wakefield accelerator is a promising tool for spectroscopic measurements. Therefore there is a requirement to create spectrometers suited to the unique properties of such a source. We demonstrate a spectrometer which achieves an energy resolution of <5 eV at 9 keV (E/∆E > 1800) and is angularly resolving the x-ray emission allowing the reference and spectrum to be recorded at the same time. The single photon analysis is used to significantly reduce the background noise. Theoretical performance of various configurations of the spectrometer is calculated by a ray-tracing algorithm. The properties and performance of the spectrometer including the angular and spectral resolution are demonstrated experimentally on absorption above the K-edge of a Cu foil backlit by laser-produced betatron radiation x-ray beam.