This report presents the conceptual design of a new European research infrastructure EuPRAXIA. The concept has been established over the last four years in a unique collaboration of 41 laboratories within a Horizon 2020 design study funded by the European Union. EuPRAXIA is the first European project that develops a dedicated particle accelerator research infrastructure based on novel plasma acceleration concepts and laser technology. It focuses on the development of electron accelerators and underlying technologies, their user communities, and the exploitation of existing accelerator infrastructures in Europe. EuPRAXIA has involved, amongst others, the international laser community and industry to build links and bridges with accelerator science — through realising synergies, identifying disruptive ideas, innovating, and fostering knowledge exchange. The Eu-PRAXIA project aims at the construction of an innovative electron accelerator using laser- and electron-beam-driven plasma wakefield acceleration that offers a significant reduction in size and possible savings in cost over current state-of-the-art radiofrequency-based accelerators. The foreseen electron energy range of one to five gigaelectronvolts (GeV) and its performance goals will enable versatile applications in various domains, e.g. as a compact free-electron laser (FEL), compact sources for medical imaging and positron generation, table-top test beams for particle detectors, as well as deeply penetrating X-ray and gamma-ray sources for material testing. EuPRAXIA is designed to be the required stepping stone to possible future plasma-based facilities, such as linear colliders at the high-energy physics (HEP) energy frontier. Consistent with a high-confidence approach, the project includes measures to retire risk by establishing scaled technology demonstrators. This report includes preliminary models for project implementation, cost and schedule that would allow operation of the full Eu-PRAXIA facility within 8—10 years.

In this paper, a set of equations for relative motion description in lunar orbits is presented. The local-vertical local-horizon frame is selected to describe the relative dynamics of a chaser approaching a target in lunar orbit, allowing the development of relative guidance and navigation systems for rendezvous and docking. The model considers the Earth and Moon gravitational influence on the two spacecraft, which are assumed to have negligible masses. The proposed equations are intended for the study of rendezvous missions with a future cis-lunar space station, whose development is currently investigated by several space agencies as the next step for space exploration.

Relative guidance algorithms for space applications were identified by several space agencies as an enabling technology for future missions development. Whenever two or more space vehicles must coordinate their motion, or a terminal rendezvous has to be performed, a robust control of the relative motion occurring between the objects is necessary. Control must guarantee operation safety, and minimize fuel consumption, since refueling operations are currently too expensive. In this context, the paper proposes an extended linearization technique to design a nonlinear H-infinity controller for the relative motion. The developed controller is designed to minimize propellant consumption and to attenuate disturbances due to typical perturbations of low Earth orbits, such as atmospheric drag and J2 perturbation. Terminal rendezvous and formation control simulations were performed using data from realistic missions.

The paper presents a novel application of the State Dependent Riccati Equation (SDRE) guidance approach with state constraints for a chaser spacecraft in the close proximity of a passive target. The dynamics are described by full 6 degree of freedom rigid-body relative motion. The final trajectory is defined by a passively safe approaching cone, which acts as path constraint and follows the attitude motion of target. A Near Rectilinear Halo Orbit in the Earth-Moon system is the selected rendezvous scenario to fully validate the proposed solution, even though the parameters related to the constraints and weighting functions are kept as general as possible, thus applicable to other similar missions.

This document reviews the physics program of the KLOE-2 detector at DAΦNE upgraded in energy and provides a simple solution to run the collider above the φpeak (up to 2, possibly 2.5 GeV). It is shown how a precise measurement of the multihadronic cross section in the energy region up to 2 (possibly 2.5) GeV would have a major impact on the tests of the Standard Model through a precise determination of the anomalous magnetic moment of the muon and the effective fine-structure constant at the M Z scale. With a luminosity of about 10 32 cm −2 s −1 , DAΦNE upgraded in energy can perform a scan in the region from 1 to 2.5 GeV in one year by collecting an integrated luminosity of 20 pb −1 (corresponding to a few days of data taking) for single point, assuming an energy step of 25 MeV. A few years of data taking in this region would provide important tests of QCD and effective theories by γγ physics with open thresholds for pseudo-scalar (like the η ′ ), scalar (f 0 , f ′ 0 , etc...) and axial-vector (a 1 , etc...) mesons; vector-mesons spectroscopy and baryon form factors; tests of CVC and searches for exotics. In the final part of the document a technical solution for the energy upgrade of DAΦNE is proposed.