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BASROC and CONFORM. Roger Barlow Instrumentation workshop 11 th April 2008. BASROC. British Accelerator Science Radiation and Oncology Consortium Universities + laboratories + hospitals + industry Goal is establishment of UK hadron therapy centres using FFAG technology - PowerPoint PPT Presentation
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BASROC and CONFORM
Roger Barlow
Instrumentation workshop
11th April 2008
Roger Barlow: BASROC and CONFORM
Slide 2
BASROC
British Accelerator Science Radiation and Oncology Consortium
•Universities + laboratories + hospitals + industry
•Goal is establishment of UK hadron therapy centres using FFAG technology
•UK lags behind France, Germany, Switzerland, US
•Difficulty with costs: proton accelerators are expensive
•nsFFAG should be smaller and cheaper than conventional machines
http://www.basroc.org.uk/
Roger Barlow: BASROC and CONFORM
Slide 3
Proton therapy
Irradiate with protons of energy 50-250 MeV such that they stop in the tumour.
No exposure behind the tumour.Small exposure before tumour (Bragg
peak maximum).Small spot size (mm) – can ‘paint’
dose with 3D raster scanEnergy loss damages DNA more
effectively than X raysEvidence that Carbon nuclei may be
even more effective!They’re expensive… but effective
Roger Barlow: BASROC and CONFORM
Slide 4
FFAG
Fixed Field (like a cyclotron)
B varies with space but not in time
Particles experience greater field as energy increases (like a synchrotron)
Cyclotron currents at Synchrotron energies
Roger Barlow: BASROC and CONFORM
Slide 5
FFAGCyclotron:
B constant, R varies
Nonrelativistic:
Low energies
FFAG:
R varies slightly
B varies with R but not t
High currents
High energies
Rapid acceleration
Synchrotron:
R constant, B varies
Magnets cycle
Low currents
Roger Barlow: BASROC and CONFORM
Slide 6
FFAG frequencies
As particle energy increases: v increases T falls f increases L increases T increases f fallsFor cyclotrons these cancel exactlyFor FFAGs these may cancel
approximately. May get away with constant RF frequency
Or can scan using low Q Finemet cavities. Go from CW to pulsed operation – high frequency and high duty cycle
~MHz
~kHz
~50%
Roger Barlow: BASROC and CONFORM
Slide 7
Properties and Uses
Hadron therapy
Muon acceleration
Proton drivers
Rapid acceleration
DC magnets
High duty cycle
High Rep rate
Variable energy extraction
Large acceptance
Roger Barlow: BASROC and CONFORM
Slide 8
FFAG energies
Increase in p= increase in B x increase in R
How big an increase in B can we manage?
• Magnet design
• Lattice
Realistic – factor 2: Optimistic – factor 5
How big an increase in R can we manage?
Realistic – factor 1: Optimistic – factor 2
Roger Barlow: BASROC and CONFORM
Slide 9
nsFFAGs
Conventional (scaling) FFAGs:
B( R)Rk
No Chromaticity:
Focussing scales with momentum
Constant tune
resonances avoidable
Nonscaling FFAGs: B(x)x
Focussing changes with momentum
resonances unavoidable but harmless(?)
More compact aperture
More compact ring (all magnets bending)
Never been built!
Roger Barlow: BASROC and CONFORM
Slide 10
1st Project: CONFORM
CONFORM - the COnstruction of a Non-scaling FFAG for Oncology, Research and Medicine
• Build world’s first nsFFAG: EMMA• Design an nsFFAG for hadron therapy: PAMELA• Look for other applications for nsFFAGs
£5.6 M funded through the Basic Technology Programme
http://www.conform.ac.uk/
Roger Barlow: BASROC and CONFORM
Slide 11
EMMA
Electron Machine with Many Applications
World’s first non-scaling FFAG
Accelerates electrons from 10 to 20 MeV in 16 turns
42x2 Quads
Off-axis for bendingMajor components ordered
Build starts summer 08
Commissioning Summer 09
Roger Barlow: BASROC and CONFORM
Slide 12
Applications
• Study effect of ions on cells (Surrey)
• High current proton accelerators for ADSR
• Muon accelerator for neutrino factory/muon collider
• High current proton accelerators for muon and neutron sources
Roger Barlow: BASROC and CONFORM
Slide 13
The ADSR
Accelerator Driven Subcritical Reactor
Accelerator
Protons ~1 GeV
Spallation Target
Neutrons
Reactor Core
Neutron multiplication factor typically k=0.98
Roger Barlow: BASROC and CONFORM
Slide 14
ADSR properties
• Manifestly inherently safe: switch off the accelerator and the reactor stops
• Uses unenriched 238U or 232Th as fuel• Thorium has very nice properties: proliferation-
resistant and short lived wastes• Large flux of neutrons can transmute waste from
conventional reactors (especially Pu)
Workshop May 7th at Daresbury
Roger Barlow: BASROC and CONFORM
Slide 15
Accelerator requirements
Proton Energy ~ 1 GeV For 1GW thermal power:• Need 3 1019 fissions/sec (200 MeV/fission)• 6 1017 spallation neutrons/sec (k=0.98 gives 50
fissions/neutron)• 3 1016 protons/sec (20 spallation neutrons each)Current 5 mA. Power = 5 MWHigh current rules out synchrotron Compare: PSI proton cyclotron: 590 MeV, 72 MeV injection2mA, 1MW
Roger Barlow: BASROC and CONFORM
Slide 16
KURRI
3 stage FFAGs at 120Hz0.1 – 2.5 MeV
2.5 – 20 MeV ( ½)
20 – 150 MeV (?)
Current ~1 nA
‘ADS demonstrator’
Aim: study neutron production
Roger Barlow: BASROC and CONFORM
Slide 17
PAMELA
Protons up to 250 MeV, Carbon ions up to 400 MeV/nucleon
Designs being considered
Goal is design we can take to MRC/NHS/Charities for funding at ~£50M
Roger Barlow: BASROC and CONFORM
Slide 18
Problems
• Injection and extraction are difficult
• Successive orbits are close together
• Gaps are small
• If we can break symmetry – racetrack instead of circle – life gets a lot easier
• Even so, the fewer rings the better
Roger Barlow: BASROC and CONFORM
Slide 19
PAMELA
Parameters
• Accelerate proton and carbon
• Dose rate 2-10 Gy/minute
• Voxel size 4x4x4 to 10x10x10 mm
• ~100 pulses per voxel to give dose control
• Cycle 100-1000 Hz
• Treatment time ~300 sec
Roger Barlow: BASROC and CONFORM
Slide 20
Treatment Scenario
Deliver doses at ~100 HzScan in 2D position through gantry
and beamline magnets, and in energy(=depth). Order not yet fixed
Need to reject pulses if patient alignment wrong or if dose already reached. (We have plenty of pulses, not a problem)
Need to know WHAT is being delivered and WHERE it is being delivered and WHERE you want it
Maybe 1+ GeV protons for tomography and 400 MeV/u Carbon for therapy?
Roger Barlow: BASROC and CONFORM
Slide 21
And so
… we need Instrumentation ideas