# Characterisation of a laser plasma betatron source for high resolution x-ray imaging

O.J. Finlay, J.-N. Gruse, C Thornton, Ric Allott, Chris Armstrong, C.D. Baird, N. Bourgeois, Ceri M. Brenner, Silvia Cipiccia, Jason Cole, C Gregory, Steven Jamison, Y. Katzir, N.C. Lopes, S.P.D. Mangles, C.D. Murphy, Z. Najmudin, David Neely, Laura Rhian Pickard, Kevin D PotterP.P. Rajeev, Dean R. Rusby, MP Selwood, D.R. Symes, C.I.D. Underwood, J.C. Wood, A G R Thomas, M.J.V. Streeter

Research output: Contribution to journalArticle (Academic Journal)peer-review

## Abstract

We report on the characterisation of an x-ray source, generated by a laser-driven plasma wakefield accelerator. The spectrum of the optimised source was consistent with an on-axis synchrotron spectrum with a critical energy of $13.8^{+2.2}_{-1.9}$ keV and the number of photons per pulse generated above 1 keV was calculated to be $6^{+1.2}_{-0.9} \times 10^{\, 9}$. The x-ray beam was used to image a resolution grid placed 37 cm from the source, which gave a measured spatial resolution of 4 µm ×  5 µm. The inferred emission region had a radius and length of 0.5 ± 0.2 µm and 3.2 ± 0.9 mm respectively. It was also observed that laser damage to the exit aperture of the gas cell led to a reduction in the accelerated electron beam charge and a corresponding reduction in x-ray flux due to the change in the plasma density profile.
Original language English 084010 Plasma Physics and Controlled Fusion 63 8 13 Jul 2021 Published - Aug 2021