Development of NS-FFAG EMMA & PAMELA

Takeichiro Yokoi

Introduction ...• FFAG(Fixed Field Alternating Gradient) Accelerator has an ability

of rapid particle acceleration with large beam acceptance. wide varieties of applications

Particle physics -factory, muon source, proton driver

-factory-factory

FFAGMedical

Particle therapy, BNCT, X-ray source

Particle Particle therapytherapy

FFAG

Energy ADSR, Nucl. Transmutation

ADSRADSRFFAG

CONFORM CONFORM ((Construction of a Non-scaling FFAG for Oncology, Research and Medicine) aims to develop the Non-scaling FFAG as a versatile accelerator. (Project HP: www.conform.ac.uk)

EMMA

PAMELA

(PAMELA)

Scaling FFAG & Non-Scaling FFAGBoth have large acceptance and ability of fast acceleration * Acceleration speed of fixed field accelerator is unlimited (in synchrotron, ramping speed of magnet limits the repetition rate)

Scaling FFAG Similar orbit shape Large beam excursion Stable betatron tune Combined function(Brk)

Non-Scaling FFAG Non-similar orbit shape Small beam excursion (small path length variation) Large tune change Linear lattice (quadrupole etc)

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Already Constructed

PoP FFAG(KEK)

It has never been built

EMMA

CONFORM : Construction of a Non-scaling FFAG for Oncology, Research and Medicine

EMMA ( PM: R.Edgecock ) Rutherford Appleton Lab Daresbury Lab. Cockcroft Ins.

Manchester univ. John Adams Ins. BNL (US) FNAL (US) CERN LPNS (FR) TRIUMF (CA)

PAMELA (PM: K.Peach) Rutherford Appleton Lab Daresbury Lab. Cockcroft Ins.

Manchester univ. Oxford univ. John Adams Ins. Imperial college London Brunel univ. Gray Cancer Ins. Birmingham univ. FNAL (US) LPNS (FR) TRIUMF (CA)

JAI team (alphabetical)

J. Cobb, K. Peach, S. Sheehy, H. Witte T. Yokoi, (G.Morgan)

Two main projects are going on ….. (1) EMMAEMMA: Construction of electron machine (prototype for muon accelerator)

(2) PAMELAPAMELA : Design study of NS-FFAG particle therapy facility ( Proton & Carbon )

EMMA: Electron Model for Many Applications

Electron NS-FFAG as a proof of principle is to be built as 3-year project.(host lab: Daresbury lab.)

It is a scaled-down model of muon accelerator for neutrino factory. Research items are . . . (1) Research of beam dynamics of NS-FFAG (2) Demonstration of NS-FFAG as a practical accelerator (3) Demonstration of fast acceleration with fixed frequency RF

3mm(normalized)Acceptance

1.3GHzRF

10~20MeV(variable)Extraction energy

10~20MeV(variable)Injection energy

16.57mCircumference

42 (doublet Q) Number of Cell

5m5m

Muon Acceleration

EMMA development in Oxford

(1) Magnet design

(2) Tracking in 3D field

(3) Injection & Extraction

Vertical tune

Baseline model

Tracking

PAMELA : Particle Accelerator for MEdicaL Applications

Advantage of particle therapy : good dose concentration and better biological effectiveness Advantage of FFAG : (1) Higher intensity (compared to ordinary synchrotron ) (2) Flexible machine operation ( compared to cyclotron ) (3) Simultaneous(multi-port) beam extraction

Standard Photons

Standard Protons

photonphoton protonproton

PAMELA : design study of particle therapy facility for proton and carbon using NS-FFAG ( prototype or slow accelerating NS-FFAG Many applications!!! Ex. ADSR )

Spot scanning

PAMELA : Medical requirement Simultaneous energy and intensity modulation is a requirement for flat dose distribution in spot scanning

Intensity modulation of 1/100 is required to achieve the dose uniformity of 2%.

1kHz repetition can scan more than 100 voxel/sec 1 kHz repetition is a present goal (impossible for synchrotron)Medical requirements are now getting clear

By G. Morgan

PAMELA : Beam Dynamics

Field imperfection severely affects beam blow up in the resonance

crossing

rf: 5kv/celldx: 100µm(RMS)

dx: 10µm(RMS)

dx: 1µm(RMS)

Beam blow up rate can be estimated quantitatively Design Criteria for proton NS-FFAG is now in hand !!

Integer resonance

Half integer resonance

Challenges: Understanding the Challenges: Understanding the

dynamics in resonance crossingdynamics in resonance crossing

~2m

PAMELA : Lattice

Integer resonance crossing must be circumvented. Tune-stabilization by introducing higher order multipole field is required

One feasible option : Non-Linear NS-FFAG (simplified scaling FFAG) : B=B0 (R/R0)k B=B0 [1+k∆R/R0+k(k-1)/2 (∆R /R0 )

2 ····] * Eliminating higher order multipole

By S. Sheehy

(1) Long straight section (~2m)

(2) Small tune drift ( <1)

(3) Limited multipole (Up to decapole)

Beam dynamics is being investigated

Doable lattice option is now in hand !!

Challenges: Tune stabilized NS-FFAG latticeChallenges: Tune stabilized NS-FFAG lattice

PAMELA : Magnet

by H.Witte

Superposition of helical field can form multipole field

Dipole Quadrupole

DecapoleOctapole

Sectapole

Applicable to superconducting magnet Well-controlled field quality Present lattice parameters are within engineering limit

~17cm

40cm

Feasible option for magnet

Challenges: Large aperture, short length, strong fieldChallenges: Large aperture, short length, strong field

PAMELA : Beam Acceleration

time

Energy

1ms

Option 1

1mstime

Energy Option 2

Option 1: P Nrep2

Option 2: P Nrep

Multi-bunch acceleration is preferable from the viewpoint of efficiency and upgradeability

PRISM RF (Osaka univ)

Experiment using PRISM cavity is planned in this October

Beam acceleration experiment using real FFAG is also planned.

PRISM rf (Osaka univ. , Japan) has similar specifications to PAMELA

Challenges : Fast enough, but more efficient !Challenges : Fast enough, but more efficient !

1ms(PV2)

PAMELA : Beam Extraction

Resonance point

H

v

In scaling FFAG, vertical tune can be varied by changing relative field strength of bending magnets

Beam blow-up in half integer resonance can be used for resonant extraction

Fast extraction & energy variable slow extraction in fixed field accelerator !! (Ideal for practical application ex. ADS , Real Alternative of existing medium energy synchrotron )

Lattice is under investigation

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Challenges: High intensity, Flexibility, and reliabilityChallenges: High intensity, Flexibility, and reliability

PAMELA Parameter specification : Almost fixed Baseline design : by 2009 Refining design, Funding : 2010

R&Ds : Prototype helical magnet, Prototype RF cavity Multi-bunch acceleration Resources : 1 FTE engineer

EMMA Lattice : fixed Component designs : ongoing Measurement of test magnet : on going Design : to be completed by Jan 08 Construction : to be completed by Jul 09

+ 1Year of beam study

EMMA Lattice : fixed Component designs : fixed Measurement of test magnet : on-going Design : fixed (production : on-going) Construction : to be completed by Jul 09

+ 1Year of beam study

Status & Schedules ...

PAMELA Parameter specification : Almost fixed Baseline design : by 2009 Refining design, Funding : 2010

R&Ds : Prototype helical magnet, Prototype RF cavity Multi-bunch acceleration Prototype Ring Resources : 1 FTE engineer