Accelerator Design for FFAG-KUCA　 ADSR

Y.Ishi Mitsubishi Electric Corp.July 7 2003

What is ADSR?Accelerator Driven Subcritical Reactor

charged particle

accelerator

subcritical reactor

target for generating neutron

Beam off chain reaction stopsSafer system !

FFAG for ADSRAccelerators should have high power efficiency

Pbeam / Ploss > 30%FFAG • Fixed field

-extremely high rep. rate(1kHz) high intensity

-superconducting magnet small Ploss

• Alternating gradient -compact size

ADSR in Kyoto University Research Reactor Institute(KURRI)

Feasibility study of ADSR

Five-year program 2002 – 2006

Subject1. Accelerator technology -variable energy FFAG 2. Reactor technology -basic experiments for energy dependence

of the reactor physics

Beam specifications

Beam species

Energy

Average beam current

Rep. rate

H ＋

20-150MeV

1A

120Hz

H ＋

200MeV

100A

１ kHz

future upgradebasic experiments

FFAG – KUCA ADSR system schematic diagram

ion source

injector

main ring KUCA

subcritical reactor

booster

100keV 2.5MeV 20MeV 150MeV

Parameters of the Accelerator Complex

Einj

Eext

Lattice type

Acc. scheme

# of cells

k value

coil/pole

Pext/Pinj

Rinj

Rext

Injector

100keV

2.5MeV

Spiral

Induction

8

2.5

coil

5.00

0.60m

0.99m

Booster

2.5MeV

20MeV

Radial DFD

rf

8

4.5

coil

2.84

1.42m

1.71m

Main ring

20MeV

150MeV

Radial DFD

rf

12

7.6

pole

2.83

4.54m

5.12m

Beam intensity schedule

Ion source

Injector inj.

Injector ext.

Booster inj.

Booster ext.

Main ring inj.

Main ring ext.

Scheme

continuous

continuous

12-turn

1-turn

1-turn

1-turn

pulse length

50s

5s

5s

50ns

50ns

65ns

peak current

5mA

-

32mA

-

2.4A

-

1.6A

Efficiency

90%

70%

80%

95%

95%

95%

<I>=1.6A ×65ns ×1kHz = 108A

Injector

Space charge effects in the injector

x=0.05,

y=0.16

when

x=50mm-mrad

y=100mm-mrad

Pulse structure of the beam

continuous injection to the injector

compressed pulse from the injector

Vgap=2kV

Vgap=30kV

acc. period spill

5s

acc. Voltageinjection

50s

Acceleration voltage pattern

Injection efficiency of the injector

0

20

40

60

80

100

120

0 1 2 3 4 5EnergyGain(keV/ turn)

Inje

ctio

n E

ffici

ency

(%)

K=4.5K=3.0

Specifications of the injectoritem

Energy<I>

Rep. ratePulse length

kspiral angle

tuneSize

Weight

MeV２．５μ A０－２

Hz- 1kHz１２０μ s１－５

3500Wx6000Dx2500H３０ｔ

(2.2,1.3)

specs

40 degree2.5

Lattice structure of the booster

Lattice functions of the booster

T （ MeV)

B （ Tm)

k

Vrf(kV)

Rmin(m)

Rmax(m)

frev(MHz)

BF/FD

tune

injection

2.5

0.2286

1.346

1.467

2.412

0.633/0.633

extraction

20

0.6496

1.650

1.774

5.564

1.487/1.487

4.5

3(10)

(3.24,1.56)

Specifications of the booster

Variable energy

• Extraction energy of the injector is fixed at 2.5MeV

• Momentum ratio in the main ring is fixed at 2.81

• Need to vary k value in the booster

k T(MeV) T(MeV)

booster main ring

0.5 3.0 23

4.5 20 150

Tune vs k

0

0.5

1

1.5

2

2.5

3

3.5

0 1 2 3 4 5

nxny

ｋ

Flat-pole multi-coil

B=B0(r/r0)k

Current distribution of the booster coil

0

500

1000

1500

2000

2500

1 2 3 4 5 6 7 8 9 10111213 141516 17181920 2122

Coil No.

[A]

電流

2d calculation of magnetic field

k value vs r

0

1

2

3

4

5

6

7

160 170 180 190 200 210

r [cm]半径

k v

alue

Specifications of the main ring(the same design as KEK 150MeV)

T （ MeV)

B （ Tm)

k

Rmin(m)

Rmax(m)

frev(MHz)

BF/FD

tune

injection

20

0.6496

4.451

4.633

2.106

0.678/0.398

extraction

150

1.8390

5.023

5.229

4.651

1.699/0.998

7.6

(3.73,1.55)

Layout

Main ring

Booster

Injector

4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3

Ion source and injector(competitive bid) Design and engineering

construction

assembly and testing

installation and alignment

on site testingBooster

Design and engineering

constructioncomponent testing

installation and alignment

on site testingMain ring

Engineering

constructioncomponent testing

installation and alignment

on site testingSystem

commissioning

2003 2004 2005

Construction Schedule