FFAG Studies at BNL

FFAG Studies at BNL

Alessandro G. RuggieroBrookhaven National Laboratory

FFAG’06 - KURRI, Osaka, Japan - November 6-10, 2006

November 8, 2006 A.G. Ruggiero (BNL) -- FFAG'06 2 of 17

FFAG Studies at Brookhaven

South Corner: Muons

Palmer, Berg, … North Corner: Protons

Ruggiero, Trbojevic

Dejan -> Medical, Gantry, eRHIC,…

Sandro -> AGS-FFAG,

Neutrino Factory,

MA-LE-PD, (RIA, electrons,…)


AGS-FFAGNew AGS Injector for Upgrade to 1-4 MW at 28 GeVRep Rate 2.5 - 5.0 HzProtons 1014 pppCircumference 809 mFFAG FDF Triplet

Non-Scaling Lattice Linear Field Profile

Linac FFAG AGS After-Burner

400 MeV 1.5 GeV 20 GeV 40 GeV

All in the same AGS Tunnel

FFAG Reference Design


NuFact - Requirements

Kinetic Energy 5 - 15 GeV 11.6 GeVAverage Power 4 MW 4 MWRepetition Rate 50 Hz 50 HzNumber of Bunches 3 - 5 5Bunch Length (rms) 1 - 3 ns 2 ns

Number of Protons 4.31 x 1013 per pulseProtons per Bunch 0.862 x 1013


Accelerator Architectures

Rapid-Cycling SynchrotronsSuper-Conducting LinacsFFAG (cyclotrons, RLA, microtrons, …)

SCL CEBAF

Dog-Bone

FFAG

The case for a Non-Scaling FFAGA.G. Ruggiero, BNL Report C-A/AP/219, Oct. 2005also in proceedings of NuFact’06, Frascati, June 2005


FFAG Accelerators for Proton Driver

F F D

Extraction Trajectory

Injection Trajectory

Single-turn Extraction

Single-turn Transfer

400-MeV Injector

3 FFAG Rings0.4 - 1.5 GeV1.5 - 4.45 GeV4.45 - 11.6 GeV

Multi-turn Injection

FFAG’s are Non-Scaling of about the same circumference and similar structure, located in the same enclosure. Bunch Compression is done in the last ring at the end of acceleration.

The scheme allows flexibility of choice of energy, intensity, rep rate. It can suit any requirements for muon production and collection


Three - FFAG Accelerator Rings (1)Injector Ring *

Low-EnergyRing

High-EnergyRing

Kinetic Energy: Inj. Ext.

GeV 0.401.50

1.504.45

4.4511.6

Inj. Ext.

0.71310.9230

0.92300.9847

0.98470.9972

p/p ±% 40.45 40.43 40.41

Circumference m 807.091 817.852 828.613

No. of Periods 136 136 136

Period Length m 5.934 6.014 6.093

Harmonic Number 75 76 77

RF

= 10.7612 m

MHz

MHz/ms

19.8925.69

0.6

26.0627.78

0.2

28.1728.50

0.03

* A.G. Ruggiero, “1.5-GeV FFAG Proton Accelerator for the AGS Upgrade”, Invited Talk to EPAC-04, July 6-11, 2004, Lucerne, Switzerland. Ta = 10 ms


Lattice Parameters

D FFS S

gg

Non-Scaling Lattice

InjectorRing

Low-Energy Ring

High-EnergyRing

Drifts: S g

mm

2 x 1.267250.30

2 x 1.285880.3044

2 x 1.30450.3088

F-sector: Length Field min Field max Gradient

mkGkG

kG/m

0.70-0.784093.7944526.5817

0.71029-1.849188.9487660.8858

0.72059-4.2351820.4415139.476

D-sector: Length Field min Field max Gradient

mkGkG

kG/m

1.401.83450

-1.39962-23.2956

1.420584.32645

-3.30084-53.3590

1.441189.90888

-7.51787-122.236

x max, in F in D

cmcm

17.2213.88

17.4614.07

17.6914.26


Linear Field Distribution (kG vs. cm)

Injector Ring

High-Energy

Ring

Low-Energy Ring


Lattice Functions

Phase Adv. / Cell H V

105.234o

99.9395o

Betatron Tune, H V

39.75537.755

Nat. Chromaticity, H V

-0.9263-1.8052

Transition Energy, T 105.482 i

All Rings

Linear Field Profile

Injection Extraction


Tune Variation & Radial Compactnesssame result for all Rings

QH

QV

x in cm

s in m injection

extraction

= (p - pinj) / pinj

F D F

Half a Period


Three - FFAG Accelerator Rings (2)

Injector Ring

Low-EnergyRing

High-EnergyRing

Energy Gain / Turn MeV 0.25 0.50 1.00

No. of Revolutions 4400 6000 7200

RF Peak Voltage MVolt 0.50 1.00 2.00

Acceleration Period ms 13.962 16.776 19.514

Injection Period ms 4.924 -- --

Repetition Rate Hz 52.95 59.61 51.25

Gap Voltage kVolt 50 50 50

Gaps per Cavity 2 2 2

No. of Cavities 5 10 20


Three - FFAG Accelerator Rings (3)

Injector Ring

Low-EnergyRing

High-EnergyRing

Protons / Cycle 4.31 x 1013 4.31 x 1013 4.31 x 1013

Average Current mA 0.345 0.345 0.345

Average Power MW 0.517 1.53 4.0

Nor. Emittance (full) mm-mrad 400 400 400

Act. Inj. Emittance mm-mrad 393.3 166.8 70.1

Half Vert. Beam Size cm 6.87 4.47 2.90

Half Hor. Beam Size cm 4.43 2.89 1.87

Bunching Factor, B / √2π 2.0 4.0 8.0

rms Bunch Length, ns 7.2 3.6 1.8

Tune-Shift 0.272 0.127 0.048

Injection

Injection


RF Frequency & Power

Injector Ring

Low-Energy

Ring

High-Energy

Ring

MHz

MHz

MHz MW

MW

# turns

# turns

# turns

# turns

# turns

# turns

MW

250 kW/cavity


Injector Ring and InjectionInjection Energy MeV 400

H– Source Current mA 35

RFQ Transmission % 80

Chopping Ratio % 5/75 x 75

Inject. Beam Current mA 1.4

Inj. Protons / turn 0.33 x 1011

Injected Turns 1306

Pulse Length ms 4.924

Duty Cycle 0.246

Chopping Frequency MHz 1.326

B1B2

C1 Foil C2From DTL

Injection Orbit

Bump Orbit

RF Ion Source ?

4 cm x 4 cm foil

17 cm

25 cm

14 cm


Extraction and TargettingThe Revolution Period at Extraction from the High-Energy Ring

T0 = 2.70 µsBeam Bunches are extracted individually every n turns

Pulse Duration

n = 1 n T0 = 2.70 µs 10.80 µs2 5.40 21.603 8.10 32.404 10.80 43.205 13.50 54.00

Kicker Septum

F D F F D F F D F


NuFact - Conclusions

FFAG Accelerators for Neutrino Factories are feasible Issues:

Space Charge at Injection

Multiple Resonance Crossing

Injector Linac (400-MeV DTL or ????)

Multi-turn Injection of H–

Magnet Feasibility

Fast RF sweep (ferrite, RF power)

Collimation

Numerical Tracking

Cost Estimate It is possible to raise the Repetition Rate --> 1 kHz

or CW Mode of Operation (Harmonic Number Jump)

Documents

FFAG Studies at BNL