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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
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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