BASROC and CONFORM
This overview highlights the key discussions from the BASROC (British Accelerator Science Radiation and Oncology Consortium) and CONFORM workshops, focusing on the establishment and development of UK hadron therapy centers using Fixed Field Alternating Gradient (FFAG) technology. The workshops, held in April 2008, addressed challenges such as the high costs of proton accelerators compared to conventional machines, and proposed solutions through innovative nsFFAG designs. These advancements promise more effective cancer treatments while aiming to enhance the UK’s standing in the field of radiation therapy.
BASROC and CONFORM
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Presentation Transcript
BASROC and CONFORM Roger Barlow Instrumentation workshop 11th 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 • 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/
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 scan Energy loss damages DNA more effectively than X rays Evidence that Carbon nuclei may be even more effective! They’re expensive… but effective
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
FFAG Cyclotron: 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
FFAG frequencies As particle energy increases: v increases T falls f increases L increases T increases f falls For cyclotrons these cancel exactly For 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 ~kHz ~50% ~MHz
Properties and Uses Hadron therapy Muon acceleration Proton drivers Rapid acceleration DC magnets High duty cycle High Rep rate Variable energy extraction Large acceptance
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
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!
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/
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 bending Major components ordered Build starts summer 08 Commissioning Summer 09
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
The ADSR Accelerator Driven Subcritical Reactor Reactor Core Neutrons Protons ~1 GeV Accelerator Neutron multiplication factor typically k=0.98 Spallation Target
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
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 MW High current rules out synchrotron Compare: PSI proton cyclotron: 590 MeV, 72 MeV injection 2mA, 1MW
KURRI 3 stage FFAGs at 120Hz 0.1 – 2.5 MeV 2.5 – 20 MeV ( ½) 20 – 150 MeV (?) Current ~1 nA ‘ADS demonstrator’ Aim: study neutron production
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
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
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
Treatment Scenario Deliver doses at ~100 Hz Scan 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?
And so … we need Instrumentation ideas
