Laser-driven positron sources for applications in fundamental science and industry

Abstract

Sub-micron defects represent a well-known fundamental problem in manufacturing since they significantly affect performance and lifetime of virtually any high-value component. Positron annihilation lifetime spectroscopy (PALS) is arguably the only established method able to detect defects down to the sub-nanometer scale but, to date, it only works for surface studies, and with limited resolution. Here, we show that laser-driven positrons [1], once aptly collimated and energy-selected, can overcome these well-known limitations, by providing ps-scale beams with a kinetic energy tuneable from 500 keV up to 2 MeV and a number of positrons per shot in a 50 keV bandwidth of the order of 103. Numerical simulations of the expected performance of a typical mJ-scale kHz laser demonstrate the possibility of generating narrow-band and ultra-short positron beams with a flux exceeding 105 positrons/s, of interest for fast volumetric scanning of materials at high resolution [2]. The implications of these novel positron sources in industry and for the next generation of high-quality plasma-based accelerators (such as EuPRAXIA [3]) will be discussed. [1] A. Alejo, et al., Laser-Wakefield Electron Beams as Drivers of High-Quality Positron Beams and Inverse-Compton-Scattered Photon Beams, Front. Phys., 7 (2019), 49. [2] T. Audet et al., Ultra-short, MeV-scale laser-plasma positron source for positron annihilation lifetime spectroscopy, arXiv:2009.05521 (2020). [3] R. W. Assman et al., EuPRAXIA Conceptual Design Report, Eur. Phys. J. Spec. Top. 229 (2020), 3675.