BASROC and CONFORM

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/


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


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


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


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%


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


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


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!


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/


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


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


Slide 13

The ADSR

Accelerator Driven Subcritical Reactor

Accelerator

Protons ~1 GeV

Spallation Target

Neutrons

Reactor Core

Neutron multiplication factor typically k=0.98


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


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


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


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


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


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


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?


Slide 21

And so

… we need Instrumentation ideas

BASROC and CONFORM

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