Design and development of Ionization Profile Monitor for the Cryogenic sections of the ESS Linac

CEA Saclay, Institut de Recherche sur les lois Fondamentales de l’Univers, Gif-sur-Yvette, France
European Spallation Source ERIC, Lund, Sweden

F. Benedetti is with the Département d’Électronique des Détecteurs et d’Informatique pour la Physique, Commissariat à l’Énergie Atomique et aux énergies alternatives, Saclay, 91400 France, (email: florian.benedetti@cea.fr)

Published online: 20 January 2020

Abstract

Saclay CEA/IRFU is working for the delivery of five Non-Invasive Profile Monitors in the frame of the in-kind contribution agreement signed with the European Spallation Source. Neutrons will be produced by spallation reactions of 2 GeV proton beam impinging on a Tungsten target. To accelerate protons a powerful linear accelerator of 5MW is under construction. Diagnostic devices are mandatory tools for the tuning and protection of the machine. The non-invasive profile monitors provide a measurement of the beam profile in transverse directions to the beam propagation. This project raises several physical and technical challenges including low signal detection of ions or electrons, profile distortions induced by the beam Space Charge effect and non-uniformities of electric field. Simulation and model of the critical aspects of the detector have been performed in order to prove the performance and the feasibility of the detector. A series of prototypes has been built with different readout types, and tested in real conditions at the 3MeV proton accelerator IPHI. All of them show some advantages and drawbacks revealed by the tests in real beam conditions. In this paper we present the results of the tests for the various configuration readout systems to agree with the model and simulation of the detector. In concluding remarks, we will discuss the performance of the prototypes and point out the camerabased one to be the more suitable for the final design.