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The description of physical processes with many-particle systems is a key approach to the modeling of numerous physical systems. For example in storage rings, where ultrarelativistic particles are agglomerated in dense bunches, the modeling and measurement of their phase-space distribution is of paramount importance: at any time the phase-space distribution not only determines the complete space-time evolution but also provides fundamental performance characteristics for storage ring operation. Here, we demonstrate a non-destructive tomographic imaging technique for the 2D longitudinal phase-space distribution of ultrarelativistic electron bunches. For this purpose, we utilize a unique setup, which streams turn-by-turn near-field measurements of bunch profiles at MHz repetition rates. To demonstrate the feasibility of our method, we induce a non-equilibrium state and show that the phase-space distribution microstructuring as well as the phase-space distribution dynamics can be observed in great detail. Our approach offers a pathway to control ultrashort bunches and supports, as one example, the development of compact accelerators with low energy footprints. [ABSTRACT FROM AUTHOR]

Because proficiency testing (PT) is increasingly used for the accreditation of testing laboratories and as a tool for backing up existing multilateral recognition arrangements between accreditation bodies, the question of performance and comparability of the proficiency-test providers arises. In this paper different approaches to assess the equivalence of European PT schemes and the competence of their providers are presented. As a first step a workshop is proposed to agree on a pilot study. The final aim is to create confidence in the existing PT schemes in Europe and to use them as common European tools. [ABSTRACT FROM AUTHOR]