Collimated x-rays emitted through laser-driven plasma lensing

Abstract The Laser wakefield accelerator (LWFA) can be used as a powerful x-ray source, with diverse applications, such as medical imaging, tomography and x-ray absorption spectroscopy for warm dense matter. However, due to the large x-ray divergence, typically on the order of tens of milliradians at full width at half maximum, an effective beam transport to the sample and subsequent detection becomes challenging which limits the signal to noise ratio. By using a laser-plasma lens of high density positioned a few millimetres downstream from the LWFA, x-ray radiation with only a few milliradians divergence is produced. The lens consists of nitrogen gas ionised by the drive laser, within which a wake is excited mainly by the LWFA electron bunch. As the LWFA electrons propagate through this second plasma they generate strong transverse fields, which focuses the beam and produces bright x-rays. In this work, the preliminary parametric study of the x-ray lens radiation is presented.