ESS RF Development at Uppsala University FREIA Division, Department of Physics and Astronomy Uppsala University, Sweden ESS: European Spallation Source - High intensity neutron spallation source - Construction starts in 2013 - First neutrons in 2019 - Long pulse faciliy - 22 independent instruments for the study of materials - To be built in Lund Schematic layout of the ESS accelerator FREIA develops the RF power system prototype for spoke resonator cavities, and do high power test of the first prototype spoke cryo module. The superconducting spoke resonator cavities accelerate the beam from the normal conducting section to the first family of superconducting elliptical cavities Cryomodules Cavity/module Frequency Input Energy Output Energy ESS 36 2 352.21 MHz 50 MeV 200 MeV FREIA 1 2 352.21 MHz n.a. n.a. Spoke Cavity Section Spoke Cavity Main Parameters β Length Diameter Thickness Material Operation Temperature Operation Gradient E peak /E acc B peak /E acc RF Power to Beam RF Power Input RF Power from Source RF Power for conditioning 0.50 687 mm 492 mm 4 mm Niobium 2 K 8.5 MV/m 4.1 9 mT/(MV/m) 165 kW 245 kW 350 kW 400kW ESS D. Dancila, T. Ekelöf, K. Gajewski, V. Goryashko, L. Hermansson, M. Jacewicz, N. Johansson, T. Lofnes, M. Noor, R. Ruber, A. Rydberg, R. Santiago Kern, R. Wedberg, R. Yogi, V. Ziemann. Contact: rocio.santiago [email protected] ESS Main Parameters: Average Beam Power 5 MW Pulse Repetition Rate 14 Hz Proton Kinetic Energy 2.5 GeV Beam Intensity 50 mA Beam Pulse Length 2.86 ms Bunch Frequency 352.21 MHz Total Linac Length 583 m Number of Target Stations 1 Number of Instruments 22 (44 max) Annual Operating Period 5200 h Source Proton Source LEBT Low Energy Beam Transport RFQ Radio-Frequency Quadrupole MEBT Medium Energy Beam Transport DTL Drift Tube Linac Spokes Superconducting spoke cavities Low-β Superconducting elliptical cavities High-β Superconducting elliptical cavities HEBT High Energy Beam Transport Target Solid rotating tungsten Target ESS RF Development at FREIA Typical RF system layout