A multi-shot target assembly and automatic alignment procedure for laser–plasma proton acceleration at high repetition rate are introduced. The assembly is based on a multi-target rotating wheel capable of hosting more than 5000 targets, mounted on a 3D motorized stage to allow rapid replenishment and alignment of the target material between laser irradiations. The automatic alignment procedure consists of a detailed mapping of the impact positions at the target surface prior to the irradiation that ensures stable operation of the target, which alongside the purpose-built design of the target wheel, enables operation at rates up to 10 Hz. Stable and continuous laser-driven proton acceleration at 10 Hz is demonstrated, with observed cut-off energy stability about 15%.

Laser–plasma proton sources and their applications to preclinical research has become a very active field of research in recent years. In addition to their small dimensions as compared to classical ion accelerators, they offer the possibility to study the biological effects of ultra-short particle bunches and the correspondingly high dose rates. We report on the design of an experimental setup for the irradiation of cell cultures at the L2A2 laboratory at the University of Santiago de Compostela, making use of a 1.2 J Ti: Sapphire laser with a 10 Hz repetition rate. Our setup comprises a proton energy separator consisting of two antiparallel magnetic fields realized by a set of permanent magnets. It allows for selecting a narrow energy window around an adaptable design value of 5 MeV out of the initially broad spectrum typical for Target Normal Sheath Acceleration (TNSA). At the same time, unwanted electrons and X-rays are segregated from the protons. This part of the setup is located inside the target vessel of the L2A2 laser. A subsequent vacuum flange sealed with a thin kapton window allows for particle passage to external sample irradiation. A combination of passive detector materials and real-time monitors is applied for measurement of the deposited radiation dose. A critical point of this interdisciplinary project is the manipulation of biological samples under well-controlled, sterile conditions. Cell cultures are prepared in sealed flasks with an ultra-thin entrance window and analysed at the nearby Fundación Pública Galega Medicina Xenómica and IDIS. The first trials will be centred at the quantification of DNA double-strand breaks as a function of radiation dose.

X-ray sources with high photon fluxes and small source sizes have been widely pursued in the last decades. With synchrotron and XFEL facilities being complex, scarce and not easily accessible, laser-driven x-ray sources have emerged as a promising option because of their compactness, high photon yield and micrometric source size. In this work, we present the optimisation of an x-ray source driven by means of 0.8 mJ, 35 fs laser pulses focused on a solid Cu target in air. A detailed characterisation of the main x-ray beam parameters is included. A Cu Kα flux of 2.3·10⁹ photons/s has been measured in 2π sr. Despite the simplicity of our setup, this flux is competitive with respect to that achieved with vacuum-based sources. A clear non-isotropic distribution of the x-ray continuum has been recorded, differing from the isotropic emission reported in dedicated studies. The beam is emitted within a cone with a semiangle of ≈14°, directed primarily along the target normal. Given the achieved flux, this source stands as a competitive alternative to more complex laser-driven x-ray sources operating in vacuum or in a He environment.