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ISIS, FETS and ASTeC David Findlay Head, Accelerator Division ISIS Department Rutherford Appleton Laboratory / STFC ASTeC 10 Years On, Thursday 13 October 2011. ASTeC, DL. Electron-proton dipole. ISIS, FETS, ASTeC (IBG),RAL. Dipole moment ~1 C.m. Electric field at 1 m: ~10 GV/m.
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ISIS, FETS and ASTeC David Findlay Head, Accelerator Division ISIS Department Rutherford Appleton Laboratory / STFC ASTeC 10 Years On, Thursday 13 October 2011
ASTeC, DL Electron-proton dipole ISIS, FETS, ASTeC (IBG),RAL Dipole moment ~1 C.m Electric field at 1 m: ~10 GV/m ~1030 Debye units
Overview of talk • ISISScience programmeAccelerator R&DUpgrades • Front End Test Stand • Rôle of ASTeC
But first — protons in the UK • At AERE1/Harwell/NIRNS2/RHEL/RAL: • Harwell synchrocyclotron (1949, 165 MeV, 1 µA) • PLA (Proton Linear Accelerator, 1959–1969)50 MeV, 3-tank — originally was to be 600 MeV • Harwell ~7 MV tandem accelerator • Harwell VEC (Variable Energy Cyclotron, 1965–1980s) • Nimrod, 7 GeV proton synchrotron (1964–1978) • ISIS, 800 MeV proton synchrotron (1984– ) • 1 Atomic Energy Research Establishment (1946) • 2 National Institute for Research in Nuclear Science (1957)
Aimed down runway Never built
ISIS • World’s most productive spallation neutron source(if no longer highest beam power) • Flagship STFC facility [Sci. Tech. Facilities Council] • Driven by UK’s high-power proton accelerators • UK has largest national neutron user community of any country • Accelerator physics at ISIS necessary for continuing operations— and also for enabling entire programmes on materials R&D • Need to plan for upgrades
ISIS • Fundamental purpose — to investigate structure and dynamics of molecular matter • Neutron sources complement light sources • Neutrons: ~0.1 eV → ~1Å Structure Paracetamol Atomic motions
RFQ: 665 keV H–, 4-rod, 202 MHz Linac: 70 MeV H–, 25 mA, 202 MHz, 200 µs, 50 pps Synchrotron: 800 MeV proton, 50 Hz 5 µC each acceleration cycle Dual harmonic RF system [Chris Prior] Targets: 2 × W (Ta coated) Protons: 2 × ~100 ns pulses, ~300 ns apart Moderators: TS-1: 2 × H2O, 1 × liq. CH4, 1 × liq. H2 TS-2: 1 × liq. H2 / solid CH4, 1 × solid CH4 Instruments: TS-1: 20 TS-2: 7 (+ 4 more now funded) ~340 staff
Protons to TS-2 Protons to TS-1 EPB1 and EPB2 to TS-1 and TS-2 above synchrotron
ISIS Upgrades 0) Linac and TS-1 refurbishment 1) Linac upgrade, ~0.5 MW on TS-1 2) ~3 GeV booster synchrotron: MW target 3) 800 MeV direct injection: 2–5 MW target 4) Upgrade 3) + long pulse mode option
ISIS MW Upgrade Scenarios 1) Replace 70 MeV ISIS linac by new ~180 MeV linac (~0.5 MW) 2) ~3 GeV RCS fed by bucket-to-bucket transfer from ISIS 800 MeV synchrotron (1MW, perhaps more) 3) Charge-exchange injection from 800 MeV linac (2 – 5 MW) ASTeC staff vital to success
Common proton driver for neutron source and neutrino factory • Based on MW ISIS upgrade • with 800MeV Linac and 3.2GeV RCS • Assumes a sharing of the beam • power at 3.2 GeV between the • two facilities • Both facilities can have the • same ion source, RFQ, chopper, • linac, H− injection, accumulation • and acceleration to 3.2 GeV • Requires additional RCS machine in • order to meet thepower and energy • needs of theNeutrino Factory
NF on Harwell Oxford site • Extensive geological • survey data available, • but needs work to • interpret implications • for deep excavation and • ground water activation muon FFAG decay ring to Norsaq 155 m below ground • UKAEA land now • not to be • decommissioned • until at least 2040 • (unless we pay • for it!) RLA 2 RLA 1 muon linac cooling phase rotation bunching decay ring to INO 440 m below ground
FETS — Front End Test Stand • Actually the second front end test stand at RAL • First test stand was built to test RFQ to replace ISIS Cockcroft-Walton
665 keV 4-rod 202 MHz RFQ RFQ test stand ion source, LEBT, RFQ, diagnostics
Front End Test Stand (FETS) • Key technology demonstrator for next generation of high power pulsed proton accelerators • ISIS upgrades • Neutrino factories • Future spallation neutron sources • Accelerator-driven systems • Waste transmutation • ... • Only dedicated high-power proton accelerator hardware R&D project in the UK
Key components of FETS • High-intensity, high-duty factor, H– ion source(60 mA, 2 ms, 50 pps) • Magnetic low energy beam transport (LEBT) • 324 MHz 4-vane RFQ • Medium energy beam transport (MEBT) • Very high speed beam chopper • Comprehensive beam diagnostics • Collaboration — ISIS, ASTeC, Imperial College, Warwick University, ESS Bilbao consortium, Royal Holloway,[Huddersfield, UCL]
Ion source and LEBT optimisation 60 mA H–beam current demonstrated Low measured emittance at high current in the FETS LEBT
RFQ design + manufacture RFQ cold model Integrated electromagnetic, thermal, fluid flow and mechanical design Weld test models under investigation at Imperial
Beam chopper • Essential for all high-power proton accelerators with rings • FETS chopper • Two-stage for wide-band functionality • Basis for ESS design
Helical prototype Planar prototype Re-bunching cavities
Beam diagnostics • Already in use • Current transformers • Faraday cup • Slit-and-cup scanners for time-resolved 2D emittance • Scintillators for beam profiles • Pepper-pot for 4D phase space • Being developed • Laser photo-detachment(“laser wire”)
At present • Cutting metal for RFQ • Increasing laser power for laser wire • Continuing ion source development • … • In future • Commission RFQ • Demonstrate high-quality beam chopping • Spin out hands-on accelerator expertise • …
ASTeC • Re-packaging of long-held national lab. skills— larger package than in the past • Skills NINA, SRS, Nimrod, ISIS, Diamond, ... • “ASTeC” skills enabled / continue to enableNimrod ISISESS designs (1990s, early 2000s)ISIS second harmonic RF upgradeTS-2 FETS • ISIS Accel. Theory Group ASTeC Intense Beams Group (IBG) — IBG still in ISIS R2 building