Description
Electron scattering off nuclei is a unique high-precision probe to study the structure of hadronic systems such as nuclei and nucleons, and the only one that gives access to the spatial distribution of nuclear charge and magnetism. Since the pioneering work of R. Hofstadter distinguished by the Nobel prize in 1961, decades of experimentation have led to unprecedented progress in the understanding of the internal structure of atomic nuclei. But these studies, restricted to stable targets, dried up in the late 1990s. The immense progress on electron accelerator technologies accomplished since then --such as the one represented by the advent of the ERL and its incarnation in PERLE-- constitutes a historic opportunity to extend these measurements to unstable nuclei.
Electron scattering off Radioactive Ions (e-RI) thus represents a new frontier and one of the highest and most exciting ambitions of the 21st century in nuclear physics. These ambitions are presented in the proposal entitled "A unique probe for nuclear structure in a future European radioactive ion-electron collider" by Lapoux et al. already submitted in response to this call, and which is co-authored by several authors of the present submission. Demonstrating the technical feasibility of ion trapping to achieve the high targeted luminosities for electron scattering is key to the success of this future project. DESTIN@PERLE is proposed as a stepping-stone e-RI demonstrator facility to be developed and operated later this decade in the context of PERLE in Orsay, an Energy Recovery R&D facility prioritized in the context of the European Accelerator R&D Roadmap for particle physics. PERLE in Orsay facility will provide an interaction point and dedicated infrastructures for hosting this R&D e-RI programme.
The DESTIN project includes three aspects: (1) radioactive ion beam production, purification and cooling, (2) fixed-target formation and stability, and (3) electron spectroscopy. The first objective of the DESTIN project will be to remove the technological barriers on these three aspects individually, but also to take up the challenges related to the coupling of the three sub-assemblies. The second objective is to train a new generation of physicists, engineers and technicians in these new technologies in Europe. Finally, the last objective will be to achieve world firsts in nuclear-radius physics, allowing a new generation of physicists to acquire the know-how on the analysis of electron scattering data and to extract the physics information of interest.
The advent of PERLE at Orsay offers a unique opportunity to achieve these three goals in the next decade, paving the way for an even more ambitious e-RI program in the longer term.