The ESS Accelerator. For Norwegian Industry and Research. Oslo, 24 Sept Håkan Danared Deputy Head Accelerator Division Group Leader Beam Physics

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1 The ESS Accelerator For Norwegian Industry and Research Oslo, 24 Sept 2013 Håkan Danared Deputy Head Accelerator Division Group Leader Beam Physics

2 The Hadron Intensity Frontier Courtesy of M. Seidel (PSI) and E. Laface (ESS) Håkan Danared Norwegian Industry and Research Page 2

3 Operating Spallation Neutron Sources LANSCE, USA 1977Linac+ring 800 MeV 17 ma in linac 100 kw ISIS, UK 1984RCS 800 MeV 200 ma extracted 160 kw SINQ, Switzerland 1997Cyclotron 590 MeV 2.2 ma extracted 1.3 MW SNS, USA 2006Linac+ring 1 GeV 26 ma in linac 1.4 MW J-PARC, Japan 2008RCS 3 GeV 330 ma extracted 1 MW (planned) Håkan Danared Norwegian Industry and Research Page 3

4 Planned Spallation Neutron Sources CSNS, China RCS 1.6 GeV 15 ma in linac 100 kw ISNS, India Linac+ring 1 GeV ma in linac 1 MW ESS, Sweden Linac 2 GeV 62.5 ma 5 MW Håkan Danared Norwegian Industry and Research Page 4

5 ESS Linac Parameters Particle species p Energy 2.0 GeV Current 62.5 ma Average power 5 MW Peak power 125 MW Pulse length 2.86 ms Rep rate 14 Hz Max cavity surface field 45 MV/m Operating time 5200 h/year Reliability (all facility) 95% Håkan Danared Norwegian Industry and Research Page 5

6 Ion Source and Normal-Conducting Linac Prototype proton source operational, and under further development, in Catania. Output energy 70 kev. Design exists for ESS RFQ similar to 5 m long IPHI RFQ at Saclay. Energy 70 kev->3.6 MeV. DTL design work at ESS and in Legnaro, 3.6 ->79 MeV. Design work at ESS Bilbao for MEBT with instrumentation, chopping and collimation. Picture from CERN Linac4 DTL. Håkan Danared Norwegian Industry and Research Page 6

7 Spoke Cavities and Cryomodules Superconducting double-spoke accelerating cavity, for particles with beta = 0.5, energy 79->220 MeV. Cold tuner, to mechanically fine-tune the 352 MHz resonance frequency. Cryomodule, holding two cavities at 2 K with superfluid helium. Length 2.9 m, diameter 1.3 m. Power coupler, the antenna feeding up to 300 kw RF power to the cavities. Single-spoke prototype for EURISOL Cavity design done at IPN, Orsay, and prototype cavity has been ordered. Niobium procured and sent to manufacturer. Cryomodule design highly advanced but not complete. Håkan Danared Norwegian Industry and Research Page 7

8 Elliptical Cavities and Cryomodules Superconducting five-cell elliptical cavity (not ESS). Two families, for beta = 0.67, energy 220->520 MeV and beta = 0.86, energy 520->2000 MeV. Electrical field lines in ESS-like 5-cell cavity, 704 MHz, with cross section constructed from ellipses and straight lines. Cavity and cryomodule design well advanced at Saclay. Elliptical Cavities Cryomodule Technology Demonstrator, ECCTD, to be ready ESS elliptical cryomodule (not final) with 4 5-cell cavities and 4 power couplers for up to ~1 MW peak RF power. Håkan Danared Norwegian Industry and Research Page 8

9 High-Energy Beam Transport Quadrupole doublet for linac and HEBT Example of beam profile on target (160 mm 60 mm) with a peak current density of 49 µa/cm 2 Beam expansion on target with quadrupole magnets plus two octupoles The HEBT design is a contribution from Århus. Rastering will supersede octupoles Håkan Danared Norwegian Industry and Research Page 9

10 Beam Physics Beam density from RFQ to target with aperture Longitudinal acceptance s x,y Small emittance growths in all three planes... although full beam size, including halo, is more important than RMS emittance Maximum 1 W/m beam losses allowed Effect of magnet misaligment, magneticfield errors, RF jitter on beam radius. For three different magnitudes of errors Håkan Danared Norwegian Industry and Research Page 10

11 RF Systems Main features: - One RF power source (klystron, IOT,...) per resonator - Two klystrons per modulator for ellipticals - Pulsed-cathode klystrons for RFQ, DTL and ellipticals - Gridded tubes (tetrodes or IOTs) for spokes - Klystrons grouped across RF gallery - Bundled waveguide layout SNS klystron gallery Frequency (MHz) No. of couplers Max power (kw) RFQ DTL Spokes Medium betas High betas Proposed layout of ESS linac tunnel and klystron gallery Håkan Danared Norwegian Industry and Research Page 11

12 Further Components not mentioned for lack of time - Beam instrumentation - Control system - Machine protection - Personnel protection - Cryogenics/cryoplant - Vacuum - Test stands - Conventional facilities - Installation - Commissioning plans - Upgrade possibilities - Etc. Quadrupole doublet on girder with BPMs and diagnostics box Beam-loss simulations Control-box prototype Cryogenic distribution Cryomodule test stand Håkan Danared Norwegian Industry and Research Page 12

13 Reliability and Availability ESS aim is 95% availiability for entire facility. ESS - Higher than any existing facility - Based on discussions with users - Using weighted percentage of scheduled beam power >70% averaged over 1 second For example, consider a day with: - One hour of 70% power - 4 hrs with 90% power hrs with 100% power - 6 min accelerator trip Gives an availability of 96.66%. Contribution to down time (>0.4%) E. S. Lessner and P. N. Ostroumov (2005) Håkan Danared Norwegian Industry and Research Page 13

14 Development of Prototypes Søren Pape Møller Sebastien Bousson Roger Ruber Pierre Bosland Anders J Johansson CERN The National Center for Nuclear Research, Swierk Roger Barlow Ibon Bustinduy Santo Gammino Håkan Danared Norwegian Industry and Research Page 14

15 Cost Drivers Main cost drivers are for the accelerator are - RF systems 37% - Modulators 15% - Klystrons 14% High Beta RF System Costs LLRF & Controls 9% - Elliptical cryomodules 19% - Cryogenics 14% Modulator 40% Klystron 39% Distribution 12% Håkan Danared Norwegian Industry and Research Page 15