CYCLOTRONS FOR ADS

P.Mandrillon, J.Mandrillon, M.Conjat

AIMA DEVELOPPEMENT SA

ThEC13,CERN,Geneva, October 30 2013

- The PSI outstanding Cyclotron story

- Two examples of High power cyclotron drivers

- A new single stage cyclotron design

- Conclusions

OVERVIEW

PSI 1st Single stage with

Stripping Extraction of H-

HIGH INTENSITY CYCLOTRONS:

THE PSI CYCLOTRON OUTSTANDING STORY

PSI: Hans Willax and the SIN Team in 1973

1966: SIN early Design – Feb. 1974:1st 100 mA beam

The 72 MeV Philips injector

The 590 MeV Ring Cyclotron

1984: Towards Higher intensity

The new separate sectors Injector

Old injector

72 MeV

590 MeV

The PSI Layout

PSI: For H+ High extraction Efficiency is needed

> Increasing the separation d between turns

d=R/N*(g/(g+1))/nr2

> Reducing the number of turns N with

High power new RF copper cavities.

PSI: Main difficulties for higher intensities

The 2 stages geometry is fixed: a 72 MeV Injector for the 590 MeV

Booster ring.

Difficult Points: the various injection and extraction channels

Beam « distortions » on the long (70m) transport line

OUR EXPERIENCE ON CYCLOTRON DRIVERS

FOR ADS:

Energy Amplifier, 1995

TRADE Experiment, 2001

1995:The early cyclotron proposal for driving

the Energy Amplifier

1995: The early cyclotron proposal for driving

the Energy Amplifier with a 1 GeV 3 stages Cyclotron

H-

H+ 12 sectors- 6 Monogap cavities- 2FT cavities

4 sectors-2 delta cavities

1 Flat-top cavity

2001: THE ENEA TRADE EXPERIMENT

TRIGA reactor

Driver Cyclotron

The TRADE Cyclotron Driver: Stripping Extraction of

240 MeV-H2+ Providing 3mA-120 MeV Proton Beam

60 KeV injection Line: AIMA H2+ ion

source (50 mA/cm2) + LEBT

+ axial injection with spiral inflector.

TRADE CYCLOTRON: MEDIAN PLANE VIEW

AND PRINCIPLE OF H2+ EXTRACTION

Max Energy (H2+/P) 240/120 MeV

Nominal Extr. Intensity 3 mA proton (1.5 mA H2+)

External diameter 4.4 m

# of spiral sectors 4

Current density in SC coil 44 A/mm2

Radiofrequency 70.4 MHz

#/type of RF cavities 4/delta-2 gaps

Peak Voltage (Inj/Extr) 70/200 KVolts

RF Power Losses 280 KWatt

Stripper H2+

H+

NEW ADVANCED HIGH POWER

CYCLOTRONS DESIGNS FOR ADS

Texas A&M University

• Two Stages Cyclotron: 100

MeV SF injector + 800 MeV SF

booster.

• Stack of 3 Cyclotrons in //

• Booster: 12 Flux coupled

stack of dipole magnet

sectors

• 10 Superconducting 100 MHz

RF cavities providing a 20

MeV Energy Gain/turn

• Large turn separation

allowing to insert SF beam

transport channels made of

Panofsky Qpoles (G=6T/m)

TEXAS A&M: 800 MeV SUPERCONDUCTING

STRONG-FOCUSING CYCLOTRON

TEXAS A&M: 800 MeV SUPERCONDUCTING

STRONG-FOCUSING CYCLOTRON

The DEAdALUS Project:

3 High Power 800 MeV-2 mA Cyclotron Complex

For Neutrino Experiments in the USA

Cf. Roger Barlow Presentation in this session

The DEAdALUS Project:

The H2+ injector cyclotron

Conventional H2+ extraction

XXXVIII ECPM, 9-12 May, PSI - Zurich 4

Superconducting Ring Cyclotron

<1 mA> H2+ 800 MeV/n,

<1.6 MW>, Peak power 8 MW

Injector Cyclotron

< 1 mA> H2+ 60 MeV/n

<120 kW>, peak power 600 kW

Stripper foils

Extraction 1

Extraction 2

The DEAdALUS Project

800 MeV-2 mA High Power Cyclotron Complex:

3 Cyclotron Complex for Neutrino Oscillations Experiments

An innovative conceptual design for a cost

effective, compact and reliable ADS driver

The reverse valley B-field

separate sector Ring

Cyclotron (patent pending)

The reverse valley bends Cyclotron

Achieving isochronism while keeping

vertical focusing at high energies is

challenging: isochronism implies a large

+ve radial gradient of the average B-field

resulting in a strong vertical defocusing:

Dnz2 = -(g2-1) = - (d<B>/dr)r/<B>

which could be overcome by edge and

spiral focusing(cf. PSI Ring Cyclotron)

nz2 =-(g2-1)+F2(1+2 tan2z)

F2= Field Flutter = (<B2>-<B>2)/<B>2

z= spiral angle of the sector

A simpler Separate sector Cyclotron:

=> No spiral => Stronger Flutter

= Reverse valley B-field

Proton extraction through stripping of H2+ is simple !

The AIMA Reverse valley Field Cyclotron®

A major advantage: The +ve B-field in the central region !

Triple injection central region

40° of phase acceptance

A major advantage: The B-field configuration in the central

Region allows acceleration at low energies

An injector cyclotron is not needed anymore !

Central region for H2+ multi-injection

60 KVolts injection HV

Axial injection Line

Electrostatic spiral inflector E=18KV/cm

> Superconducting Coils . Rmin: 4.2m Rmax: 7.1m

.Total length ~50m

.Section: 160 mm * 310mm

.Current density 55 A/mm²

> 6 straight hill sectors (14 tons)

> 12 small valley sectors

Return yokes could be added to reduce the coil stored

energy ( 3 times lower than in a classical booster!)

Magnetic field layout of the 1600 MeV H2+ design

RF cavities H=6 / 36.3MHz

• 6 cavities inserted in the valleys

(12 accelerations gaps / turn)

• Pumping through the stem

1600 MeV H2+ layout

• 150 kV in the center up

to 450 kV at extraction

• Q = 6200 ->Total losses

3MW

RF-delta double gap cavities

Peak Voltage versus radius

Vertical cross-section through the valley axis

Initial condition:

5mm vertical amplitude @ 155MeV

New extraction concept for H2+ stripping:

short trajectory, no focusing elements, no complexity

Extraction

Simulation of H2+ acceleration up to 1600 MeV

The reverse valley B-field concept avoids the internal loop

(cf. DAEdALUS extraction) for the stripped proton beam from H2+.

Different extraction concepts of 800 MeV protons

Easier extraction of separated turns in the reverse valley field

No septum, only passive channel with

bars either side of the median plane

Possibility to house a very efficient

radiation protection in graphite

Acceleration and extraction of 800 MeV protons

Dr for the 3 last turns with 5MeV energy gain / turn

Energy (MeV)

CONCLUSIONS

A single stage 800 MeV Reverse Valley Field Cyclotron:

a good candidate for an industrial ADS demonstrator

ADVANTAGES

• Single stage accelerator

– Low construction budget and Low operational cost

– Less components than traditional solutions high reliability

– No transport / matching issues between stages

– Compact system (lower cost for the building)

– Stored energy at least 3x smaller than in conventional 2 stages superconducting

booster

• 3 sources + axial injection lines

– redundancy

– reliability

– Intensity Flexibility:

• 8 mA protons>4mA H2+ => 2 Ion sources on + 1 Ion source in Stand-by

• 12 mA protons>6mA H2+ => 3 Ion sources on

• Simplified Extraction system : No Septa required

– Increasing reliability

– less activation => easier maintenance

REverse VAlley CycloTRON

Thank you for your attention.

Pierre.Mandrillon@aima.fr

The Dreaming Machine for ADS…