David Findlay
Head, Accelerator Division
ISIS Department
Rutherford Appleton Laboratory / STFC
ASTeC 10 Years On, Thursday 13 October 2011

ISIS, FETS,
ASTeC (IBG),RAL
Electric field at 1 m: ~10 GV/m
ASTeC, DL
Electron-proton dipole
Dipole moment
~1 C.m
~10 30 Debye units

Overview of talk
ISIS
Science programme
Accelerator R&D
Upgrades
Front End Test Stand
Rôle of ASTeC
3

But first — protons in the UK
At AERE 1 /Harwell/NIRNS 2 /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)
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Harwell tandem

PLA —
Proton
Linear
Accelerator

Aimed down runway
Never built

PLA tank going into Building R12 at RAL

PLA tank in R5.1 — as part of new injector for Nimrod

Remedial work on other tanks for new injector for Nimrod

PLA tank in R5.1 — as part of injector for ISIS

Cockcroft at ground-breaking ceremony for Nimrod

Construction of Nimrod synchrotron hall

4.6 MVA alternator (+ 5100 HP motor + 24 ton flywheel) × 2

First beam from Nimrod

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
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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
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Global challenges
Energy
Impact of ISIS science
Living with environmental change
Global threats to security
Ageing: Life-long health and wellbeing
Digital economy
Nanoscience: through engineering to application
ISIS
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ISIS from air

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 × H
2
O, 1 × liq. CH
4
TS-2: 1 × liq. H
2
/ solid CH
4
, 1 × liq. H
2
, 1 × solid CH
4
Instruments: TS-1: 20 TS-2: 7 (+ 4 more now funded)
~340 staff
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–35 kV H – ion source

665 keV 4-rod 202 MHz RFQ

70 MeV 202 MHz 4-tank H
– linac

1.3
–3.1 + 2.6–6.2 MHz 70–800 MeV proton synchrotron

Superperiods 9, 0 and 1 of 800 MeV synchrotron

Protons to TS-2
Protons to TS-1
EPB1 and EPB2 to TS-1 and TS-2 above synchrotron

ISIS TS-1 experimental hall, 20 instruments

ISIS TS-2 experimental hall, 7 instruments + 4 under way

TS-1 tungsten target, plates

TS-2 tungsten target, solid cylinder

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 800 MeV Linac and 3.2
GeV 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 the power and energy needs of the Neutrino Factory

decay ring to Norsaq
155 m below ground muon
FFAG
RLA 2
RLA 1 muon linac cooling phase rotation bunching
NF on Harwell Oxford site
• Extensive geological survey data available, but needs work to interpret implications for deep excavation and ground water activation
• UKAEA land now not to be decommissioned until at least 2040
(unless we pay for it!) 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
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ISIS 665 kV Cockcroft-Walton (1984 –2004)

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
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Key components of FETS
High-intensity, high-duty factor, H –
(60 mA, 2 ms, 50 pps) ion source
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]
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In R8 at RAL

Ion source and LEBT optimisation
Low measured emittance at high current in the FETS LEBT
60 mA H
– beam current demonstrated
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RFQ design + manufacture
RFQ cold model
Integrated electromagnetic, thermal, fluid flow and mechanical design
Weld test models under investigation at
Imperial
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Beam chopper
Essential for all high-power proton accelerators with rings
FETS chopper
Two-stage for wide-band functionality
Basis for ESS design
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4 metres 46

Helical prototype Planar prototype
Re-bunching cavities
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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”)
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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
…
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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 enable
Nimrod

ISIS
ESS designs (1990s, early 2000s)
ISIS second harmonic RF upgrade
TS-2
FETS
ISIS Accel. Theory Group

ASTeC Intense Beams
Group (IBG) — IBG still in ISIS R2 building
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ASTeC — has enabled ISIS
— is enabling FETS
— will enable ISIS upgrades
Happy birthday!
And many happy returns!
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