Http:// [email protected] A new accelerator for advanced research and cancer therapy...

http://www.adams-institute.ac.uk [email protected]

A new accelerator for advanced research

andcancer therapy

Ken PeachJohn Adams Institute for Accelerator Science

University of Oxford and Royal Holloway University of London

Princeton 11th October 2007

http://www.adams-institute.ac.uk/



mailto:[email protected]

Ken Peach John Adams Institute 11 x 07 2

Outline

• Introduction (Accelerators & Particle Physics)

• The Neutrino Factory(Why? The Muon Acceleration Challenge)

• The ns-FFAG Accelerator(non-scaling Fixed-Field Alternating Gradient)

EMMA

• Charged Particle Therapy (CPT)(proton and light-ion cancer treatment)

PAMELA

• Summary


Introduction

• There are more than 17,000 particle accelerators (> a few MeV) worldwide– Most are used in medicine

• Linacs, cyclotrons, some synchrotrons…

– Next most common in industry• Ion implantation etc

– Synchrotron Radiation Sources• Mostly synchrotrons, coming soon - linacs

– Neutron and radionuclide sources• Linacs, cyclotrons, synchrotrons, something weird

and– For particle physics!

• A few big synchrotrons (& colliders) – Often with Linacs at the front end

• And coming soon (maybe) the ILC


Classical Accelerator Types

Type Magnetic Field

RF Radius

Betatron Variable Fixed

Cyclotron Fixed Variable

Synchrotron Variable Fixed

FFAG Fixed ~Fixed

Linear acccelerators

(Linacs)

+ assorted others – electrostatic, RFQs etc …

+ new ideas (laser-plasma for example) …


The Bleeding Edge?

• Medical accelerators– Mainly linacs and cyclotrons

• Research accelerators– Mainly synchrotrons

• Particle Physics applications– Better synchrotrons (LHC)– Better linacs (ILC)

• Why do we need anything new?

– Because life presents new challenges!


HiggsHiggsBosonBosonHiggsHiggsBoson?Boson?

For

ceF

o rce

Car

rier

sC

arr i

ers

ZZ boson

WW boson

photon

ggluon

Generations of Generations of matter matter

-neutrino

tau

bbottom

ttop

III III

-neutrino

muon

sstrange

ccharm

II II

ee-neutrino

eelectron

ddown

upu

I I

Lep

tons

L

epto

ns

Qua

rks

Qua

rks

Particles and Forces

Each with its own

‘antiparticle’

© Brian Foster


The Standard ModelThe ParametersThe Parameters

• 6 quark masses– mu , mc, mt

– md, ms, mb

• 3 lepton masses– me, m, m

• 2 vector boson masses– Mw, MZ

• (m, mg=0)• 1 Higgs mass

– Mh

• 3 coupling constants– GF, , s

• 3 quark mixing angles– 12, 23, 13

• 1 quark phase–


Neutrino Factory

The “ultimate” neutrino facility






The Standard ModelThe ParametersThe Parameters

• 6 quark masses– mu , mc, mt

– md, ms, mb

• 3 lepton masses– me, m, m

• 2 vector boson masses– Mw, MZ

• (m, mg=0)• 1 Higgs mass

– Mh

• 3 coupling constants– GF, , s

• 3 quark mixing angles– 12, 23, 13

• 1 quark phase–

Neutrino sector

Neutrino masses identically 0!!!!


i

i

ii

ii

i

i

i

i

i

MNS

e

e

ccescscseccsss

scesssccecsssc

escscc

e

ecs

sc

ces

esc

cs

sc

U

1

1

1

1

1

231312231312231223131223

231312231312231223131223

1313121312

1212

1212

1313

1313

2323

2323

Neutrino Mixing

Parameters of neutrino oscillation

1 absolute mass scale

2 squared mass diffs

3 mixing angles

1 phase

2 Majorana phasesβα,

)esinθ always ( δ

θθθ

ΔmΔm

m

iδ13

132312

223

212

νe

, ,

,

221

232

231

2i

2j

2ji

ΔmΔmΔm

mmΔm

solarAtmospheric Majorana3G

cij=cosij

sij=sinij

O(1eV) masses

unknown ,,

unknown

0.045 sin

0.62)-(0.34 2tan

eV10 9.1)-(7.0

2.2)-(0.49tan

eV10 2.98)-(1.9

232

132

122

25-221

232

2-3232

mSign

m

m

2


a =22 GFneE = 7.6 10-5 E

Where is the electron density ; is the density (g/cm3) ; E is the neutrino energy (GeV)

eP

ELm

ELm

ELmsssccc 4442313122312

213

221

231

232 sinsinsinsin8

ELmccsc 4

2223

212

212

213

221sin4

EaL

ELm

ELm

ELm sssc 4

213444

223

213

213 21sinsincos8

221

231

232

231

2213211

mas

E

Lmssc 422

23213

213

213sin4

ELm

ELm

ELmsssccsssc 4442313122312231312

213

221

231

232 sinsincoscos8

ELmsssccsssccsc 4

21323122312

223

213

212

223

212

212

213

221sincos24

Why is it hard to measure the parameters?

(Richter: hep-ph/0008222)

aa

cij=cosij, sij=sinij


What to Measure?

Neutrinos

e disappearance

e appearance

e appearance

disappearance

e appearance

appearance

… and the corresponding antineutrino interactions

Note: the beam requirements for these experiments are:

high intensity known flux

known spectrum known composition (preferably no background)


CP-violation

FNAL Feasibality Study 1


A Neutrino Factory is …

… an accelerator complex designed to produce >1020 muon decays per year directed at a detector thousands of km away

Muon Acceleration

… need to accelerate muons very quickly

[@5 GeV, ~0.1msec]


Neutrino Factory cost drivers

• High Power proton drivers – MW power, ns pulses

• RLA or FFAG?– Which is cheaper?

• RF – 30% of the cost?

• Cooling– How much? (20% of the

cost?)

BNL Feasibality Study 2


The non-scaling FFAG Accelerator

Fixed-Field Alternating Gradient






Fixed Field Alternating Gradient accelerators

• Fixed-Field (like a cyclotron)

– Rapid acceleration possible– Rapid cycling possible

• Alternating Gradient (like a synchrotron)

– Focussing!!!!• Small(er) magnets/beam pipe/vacuum system

• … and large acceptance

• The best of both worlds!– So why is the world not full of FFAGs?

Type Magnetic Field RF Radius

FFAG Fixed ~Fixed


Early FFAGs (1955-1960)

• MURA built several electron FFAGs in the 1950s

20 to 400 keV machine

Chandrasekhar Bohr

Radial sector Spiral sector

Large complicated magnets• c.f. Cyclotron – large simple magnets

• c.f. Synchrotron – small simple magnets


Newer FFAG’s (post-2000)

• The Japanese have built two “proof of principle” proton FFAGs

500 keV proton FFAG @ KEK 150 MeV proton FFAG @ KEK


… but …

• Why?… the magnets are LARGE LARGE and COMPLICATEDCOMPLICATED

• Why does k have to be so large?1. Larger k means stronger focussing

2. k > 0 means horizontal focussing– This means that the average field increases with radius

3. The momentum compaction 1/(k+1)– Large momentum bite small orbit excursion p

pRR

Orbit excursion ~ 0.9m

+ k

r

rBB

00

where k >> 1

1 krp


Scaling and non-scaling FFAGs

k

r

rBB

00

where k >> 1

1 krp

k

r

rBB

00

where k = 1

LinearLinear magnets!

i.e. quadrupoles

Invented in 1999


Simpler Magnets

… the magnets are LARGE LARGE and COMPLICATEDCOMPLICATED … to something SMALLSMALL and SIMPLESIMPLE

r

B (r)


The ns-FFAG

• Should combine the advantages of FFAGs – Fixed Field

• Fast cycling (limited essentially by RF)• Simpler, cheaper power supplies• No eddy-currents• High intensity (pulsed, ~continuous)• Low beam losses• Easier maintenance and operation• Lower stresses

– Strong Focussing• Magnetic ring• Variable energy extraction• Higher energies (than cyclotrons)• Different ion species possible

• with relative ease of construction


… so … where is the catch?

• Variable tune!

Tune ~ c

Must crossresonances


Beam Acceleration

• Resonance is a coherentcoherent effect– Can fast acceleration circumvent the

resonances?• If the momentum changes by a large

amount during a single turns, is it possible to leap-frog over the resonance?

– Small variation of the path length with momentum (small momentum compaction)

• Fixed radio-frequency cavities?

10MeV

20MeV

|df/f|~0.1%

0.1ns

Plots for EMMA


Does it work?

• We do not know!– There is no “no-go” theorem

• Need for a “proof of principle” demonstrator– EMMA

• Electron Model for Many Applications– Originally Electron Model for Muon Acceleration

• Funding obtained in the UK to design and build a EMMA – the world’s first non-scaling FFAG accelerator!


Objectives of the CONFORM Project

1. Show the non-Scaling Fixed-Field Alternating Gradient Accelerators work

• Build an Electron Model (EMMA)• Design a prototype Charged Particle

Therapy machine based on ns-FFAGs• Protons and carbon ions

2. Develop applications of ns-FFAGs


EMMA Parameters

42 identical straight length 394.481 mm

Long drift 210.000 mm

F Quad 58.782 mm

Short drift 50.000 mm

D Quad 75.699 mm


Location of EMMA

Daresb

ury

Daresb

ury


EMMA at the ERLP@Daresbury

After Neil Bliss

ERLP Parameters


EMMA: Lattice & Magnets

B0 xB1

B0

xMagnet linear slide

After Neil Bliss


Diagnostics, injection & extraction

After Rob Edgecock


Status of EMMA

• Funded! (~$10M)– Started 1st April 2007

• Lattice - fixed

• Component design - ongoing– Prototype quads being measured now

• Final design - complete Jan 08

• Construction - complete Jul 09

• Beam studies - until Sep 10– At least …

After Tkeichiro Yokoi


CONFORM


PAMELA

Charged Particle Therapy (CPT)

BASROC & CONFORM






Incidence of Cancer in the UK

• 13.5% probability, all types (except skin cancer)– Around half are associated with specific risks– Statistically, some will be close to sensitive tissue

• and difficult to treat surgically or chemically

Source: Cancer Research UK


Why use protons?

After Bleddyn Jones

X-Rays100

80 80150

60

Protons

30050 50

60

0


Why use Carbon?

0

1

2

3

4

5

6

7

8

9

10

0 2 4 6 8 10 12 14

Depth in water [cm]]

effe

ctiv

e do

se [

rela

tive

units

]

photons

protons

biol. eff. dose: Carbon ions

Tumor

Daniela Schulz-Ertner, Heiddelberg

An important statisticAn important statistic

“ Radiotherapy remains a mainstay in the treatment of cancer. Comparison of the contribution towards cure by the major cancer treatment modalities shows that of those cured, 49% are cured by surgery, 40% by radiotherapy and 11% by chemotherapy”.

RCR document BFCO(03)3, (2003).

Chemotherapy provides by far the smallest contribution towards cancer cure yet is much more expensive than radiotherapy and generates a disproportionately large research and media interest.

Roger Dale, Hammersmith Hospital and Imperial College

What is RBE?RBE = Relative Biological Effectiveness.

A measure of the biological “potency” of a particular type of radiation relative to that of a reference radiation.

Reference radiation (conventional x-rays) has RBE = 1

For a given biological end-point:

Proton RBEs: ~ 1.1

Neutron RBEs: 3 - 5

Carbon ion RBEs: 3 - 5

radiationealternativwithrequiredDose

radiationreferencewithrequiredDoseRBE


The concept and definition of RBE are both straightforward. Unfortunately….

Even for a particular type of radiation, RBE is not fixed.

Its value depends on:

a) The size of the dose used at each treatment

b) The chosen biological end-point

c) The nature of the irradiated tissue



CPT facilities operating & planned


Hadron Therapy in Chiba (Japan)

Borrowed from Rob Edgecock


Cancer of the Kidney Stage I: TIa N0 M0 80GyE / 16fr. /4wks

Cancer of the Kidney Stage I: TIa N0 M0 80GyE / 16fr. /4wks

治療前

1 year1 year2 years2 years

3 years3 years4 years4 years


Prostate Cancer Results


We can do better

Monitoring and Control :Key issues for medical applications

time

Inte

gra

ted cu

rrent

Synchrotron & cyclotron

time

Inte

gra

ted cu

rrent

FFAG

Dose uniformity should be < ~2% To achieve the uniformity, precise intensity modulation is a must

Beam of FFAG is quantized. Active intensity control at the injection level and precise loss control are indispensable.

New approach to medical accelerator control is required in PAMELA (New postdoc is employed for the issue)

SOBP is formed by superposing Bragg peak

Gate width controls dose

Step size controls dose

intensity modulationintensity modulation

Takeichiro Yokoi


… much better


The requirements

• There are obvious potential benefits from proton/light ion therapy– Need to maximise the benefits

• Requirements– Rapid variable energy extraction– Rapid variable transverse spot scanning– Variable ion species– Accurate dose measurements

• Flux control


Synchrotron Cyclotron FFAG

Intensity (>100nA) Low Plenty Plenty

1-16nA >100nA

Maintenance Normal Hard Normal

Extraction eff Good Poor Good

Operation Not easy Easy Easy

Ions Yes No Yes

Variable energy Yes No Yes

Multi-extraction Possible No Yes

After Y.Mori KEK/Kyoto

Advantages of FFAG in Charged Particle Therapy


Ns-FFAG machine


PAMELA

• Preliminary ideas– Cyclotron injection @ ~20 MeV (or 8 MeV – 2 ring)– 1 or 2 ns-FFAG proton rings

• 20 MeV 250 MeV (1 ring)• 8 MeV 31 MeV & 31 MeV 250 MeV (2 ring)

– + 1 Ion ring • 69 MeV/u 450 MeV/u

– (proton ring equivalent to 69 MeV/u Carbon)


Injection and Extraction

Small beam excursion of NS-FFAG makes energy variable beam extraction easier

Unique feature for fixed field accelerator However, large tune change requires phase adjustment mechanism in injection & extraction multi-kicker system

QD QD QDQF QF QF

Kicker#2Kicker#1 Septum∆p/p=+0.0

Circulating beam

@2nd kicker

@septumSeptum boundary

By changing the field strength and direction, beam position in

phase space can be adjusted Example of beam extraction (PAMELA)


Superconducting FFAG Gantries

Fixed field of 3.7T Transports 150-400 MeV/u

Length ~15m

D Trbojevic/BNL


BASROC


Summary

• Non-scaling FFAG accelerators are:– New– Untried– Interesting for

• Neutrino physics• Cancer therapy

– And other applications » Spallation neutron sources, muon sources» Accelerator driven reactors, nuclear waste disposal

• We will know in ~3 years if they work– Let us hope that they do … they could be

very useful devices …

Http:// [email protected] A new accelerator for advanced research and cancer therapy...

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