Rob Edgecock, Roger Barlow, David Bruton, Basil Gonsalves, Carol Johnstone & Jordan Taylor Industrial partners: GE & Tesla Compact High Current FFAG for

Rob Edgecock, Roger Barlow, David Bruton, Basil Gonsalves, Carol Johnstone & Jordan

Taylor

Industrial partners: GE & Tesla

Compact High Current FFAG for Compact High Current FFAG for Radioisotope ProductionRadioisotope Production

• Reminder about FFAGs

• Status of radioisotope FFAG- results from beam dynamics- first look at machine components

• Potential performance

• Next Steps

• Conclusions

FFAGsFFAGs

Fixed Field Alternating Gradient accelerators:

Very similar to cyclotrons

Two types (sort of): scaling and non-scaling

Scaling invented in late 1950s

20 to 400 keV machine

Operated at MURA in 1956

Sector focussed

cyclotron but much larger

flutter and field gradient

Scaling for constant

betatron tunes

Bohr

Chandrasekhar

Scaling FFAGsScaling FFAGs

Re-invented in Japan in late 1990s

For muon acceleration

Has resulted in the construction of >6 scaling machines

Non-scaling FFAGsNon-scaling FFAGs

Invented in US in late 1990s

For muon acceleration

First type: linear non-scaling FFAG

o Large beam acceptance

o Parabolic time of flight

/p

Path length

/p

Travel time

27

14

8

First (and only) non-scaling FFAGFirst (and only) non-scaling FFAG

20MeV electron proof of principle accelerator

EMMA

Carbon Therapy FFAGCarbon Therapy FFAG

PAMELA – non-linear non-scaling FFAG

Our FFAGOur FFAG

More cyclotron-like

Wedge-shaped magnets

o Gradient focussing

o Edge focussing

o Weak focussing

Allows simultaneous tune and tof control

o Flat(ish) tunes

o Isochronous enough for fixed RF frequency

o CW operation

Three designs done:

o ~ 28 MeV for radioisotope production

o 330 MeV for proton therapy and proton CT

o 430MeV/n for therapy with ions up to neon

Radioisotope machineRadioisotope machine

Four identical wedge-shaped magnets

No reverse bend, fields to sextupole

Assumed 2 RF cavities – 200 keV/turn

Plenty of space for:- injection- extraction- instrumentation- pumps

Studied using COSY Infinity & Opal

Injection energy: 75 keV

Extraction: 10 MeV – 102cm 14 MeV – 120cm 28 MeV – 170cm

Performance from trackingPerformance from tracking

Time of flight

Protons to 28 MeV:

isochronous to 0.3%


Tunes

Protons to 28 MeV

250 keV – just over one turn


Acceptances14

MeV10

MeV

20 MeV 28 MeV

1 MeV


Energy/MeV 0.075 0.1 0.25 0.5 0.75 1 2 4 6 8 10 12 14 16 19 22 25 28

x/π.m.mrad 5.4 24.5 33.4 40.0 35.6 60.0 46.8 37.9 34.7 32.0 29.9 25.7 23.8 22.2 19.1 23.5 20.4 22.1

y/π.m.mrad 2.0 3.1 1.9 1.6 1.4 1.2 0.86 0.92 0.75 0.63 0.56 0.53 0.49 0.45 0.42 0.39 0.37 0.35

Acceptances

Protons to 28 MeV – huge!

In Opal, with space charge, 20mA to 28 MeV


Manufacturer Cyclotron Energy/MeV Maximum Current/mA

ACS TR30 30 ~1

ACS TR24 24 ~0.3

ACS TR19 19 ~0.3

IBA Cyclone 30 30 1.2



Siemens Eclipse HP 11 0.12

GE PETrace 16.5 ~0.1

From IAEA Tech Report 465 2008

FlexibilityFlexibility

Alphas:

28 MeV protons = 28.2 MeV α Acceleration to 28.2 MeV works with same field map TOF ~twice

- use 1st and 2nd RF harmonics?- but with small frequency change- needs to be studied

Variable energy:

10 MeV orbit moved to 28 MeV radius by simple field scaling

TOF a little worse Fixed by a very small tweak But RF frequency quite different?

InjectionInjection

Use external ion sources: - high beam current - more flexibility - easier to replace

But beam capture more difficult Usually, axial injection Various methods used to steer vertical beam into horizontal plane

InjectionInjection

Spiral inflector

Left dee

Right dee

Problems:-Complicated 3D fields-Tends to be lossy

InjectionInjection

Alternative: horizontal injection Allows higher energy Use septum, electrostatic deflector, etc to steer beam onto EO Separation between first two orbits >7cm, plenty of space Beam dynamics under investigation

Magnet ConceptsMagnet Concepts

Sector gradient magnets Scaling FFAGs and AVF cyclotrons (higher energy cyclotrons have gradient

magnets)

Several designs under study Vary gap size as a function of energy to create increasing gradient Coils - TRIUMF and PSI cyclotrons have coils to tune gradients Hybrid designs exploiting permanent magnet yoke material with

electromagnets

High energy gradient magnet (left) and hybrid permanent magnet design (right) which can be scaled to achieve the correct radial gradient. Coils can be added to slots in poles in both designs.

CavitiesCavities

Initial thoughts only Use cyclotron Dee cavity designs:

- 2 cavities- double gap(?)

- 50 kV/gap- tunable for α’s

Main issue: gap at low energy- higher energy injection?- variable voltage with energy

Central region needs optimisation Need expert input!

PSI injector double gap cavity400 kV/gap

Target OptionsTarget Options

Two possibilities

• Internal:- pass the beam through thin target many times- restore lost energy every turn- relies on large acceptance- similar to ERIT, but heavier target

• External:- multiple targets


Internal:200keV energy loss ≈ 10μm 100Mo

Yield/turn = 0.1mCi/μAh at 14 MeV

External target yield = 4.74mCi/μAh

→ 48 turns

Internal target issues:cooling

outgasingprocessing


External – two options:

• Charge exchange extraction, as used in cyclotrons:- lossy- not possible for α’s- foil heating and lifetime can be a problem

• Electrostatic deflector and septum

Radioisotope ProductionRadioisotope Production

Yields of various imaging isotopes – all identified of importance by IAEA - using Talys for 1 hr at 2mA

Isotope Production Beam Energy

Beam Typical patient

doses/hr99mTc - SPECT 100Mo(p,2n)99mTc 14 MeV p 2300123I - SPECT 124Te(p,2n)123I 28 MeV p 18000111In – SPECT 109Ag(α,2n)111In 28 MeV α 10018F - PET 18O(p,n)18F 10 MeV p 1300011C - PET 14N(p,α)11C 10 MeV p 1600068Ga - PET 68Zn(p,n)68Ga 14 MeV p 80000

Therapeutic RadioisotopesTherapeutic Radioisotopes

• All reactor produced

• None in the UK

• Supply can be a problem

• Some isotopes need α:211At, 67Cu, 47Sc, 161Tb

• Recent review said:

UK situation:

It is recommended that a national strategy for the use of radiotherapeutics for cancer treatment should be developed to

address the supply of radiotherapeutics, projected costs of drugs and resources, the clinical introduction of new radioactive drugs, national

equality of access to treatments and resource planning.

Therapeutic RadioisotopesTherapeutic Radioisotopes

• All reactor produced

• None in the UK

• Supply can be a problem

• Some isotopes need α:211At, 67Cu, 47Sc, 161Tb

• Recent review said:

UK situation:

It is recommended that a national strategy for the use of radiotherapeutics for cancer treatment should be developed to

address the supply of radiotherapeutics, projected costs of drugs and resources, the clinical introduction of new radioactive drugs, national

equality of access to treatments and resource planning.



Isotope Production Beam Energy

Beam Yield/mCi

177Lu natHf(p,x)177Lu 28 MeV p 281153Sm 150Nd(α,n)153Sm 28 MeV α 8211At 209Bi(α,2n)211At 28 MeV α 118967Cu 64Ni(α,p)67Cu 28 MeV α 1947Sc 44Ca(α,p)47Sc 28 MeV α 199225Ac 226Ra(p,2n)225Ac 19 MeV p 607

Next stepsNext steps

• Continue to search for funding!

• Continue modelling:- optimise lattice - study internal targets- study extraction and beam delivery

- look at central region and beam capture

• Engineering:- magnet design- RF design- injection and extraction - target design

→ Business case

• Aim:- build it to make and sell radioisotopes- commercialise the FFAG- proof of principle of higher energy machines

Next stepsNext steps

ConclusionsConclusions

• New type of FFAG/SFC looks very promising for:- radioisotope production- proton therapy & pCT- ion therapy

• For radioisotopes, very large acceptance:- beam current up to 20mA- possibility of internal target

• Main next step: engineering, especially magnets

• Business case would open up opportunities for construction

Documents

Rob Edgecock, Roger Barlow, David Bruton, Basil Gonsalves, Carol Johnstone & Jordan Taylor Industrial partners: GE & Tesla Compact High Current FFAG for