High Current Ion Acceleration U.Ratzinger - DESYheraeus-technology.desy.de/e8/e44865/RatzingerIons.pdf · U. Ratzinger, Institute of Applied Physics (IAP), Goethe-University Frankfurt

U. Ratzinger, Institute of Applied Physics (IAP), Goethe-University Frankfurt 1

High Current Ion Acceleration

430. WE-HERAEUS-SEMINAR“Accelerators and Detectors at the Technology Frontier”

Physikzentrum Bad Honnef, April 27’th, 2009

U.Ratzinger


Outline

1. Activities at Goethe University Frankfurt,Institute of Applied Physics

2. E - field limits in the low β-rangea) Superconducting structuresb) Room temperature structures

3. Code development for high current beams

4. High current projectsa) Ion source optionsb) FRANZc) Proton Linac for FAIRd) UNILAC Upgrade for FAIRe) FAIR Facilityf) RF acceleration of p from laser source


• New Physics Faculty building in Frankfurt-Riedberg with 1100 m2

Experimental Hall.- First occupancy in March 2005.- Experiments in accelerator, atomic, nuclear and plasma physics.

• FRANZ (Frankfurt Neutron Source at the Stern-Gerlach-Zentrum) is the first lighthouse project within the Stern-Gerlach-Center.

Frankfurt Physics Faculty


Accelerator physics

U. RatzingerA. SchemppN. N.N. N.

Plasma physics(in house plasmas and ion beam driven

experiments at GSI, FAIR)

J. JacobyN. N.

Astrophysics(detector development,

Exp. at FAIR, FRANZ)

N. N.

Institute of Applied Physics (IAP) Structure


IAP Structure

r process

fusion up to iron

p process

rp process

number of neutrons

num

ber

of p

roto

ns

s process

r process

fusion up to iron

p process

rp process

number of neutrons

num

ber

of p

roto

ns

s process

• Investigation of stellar r - and s - processes at FRANZ and FAIR.

• Investigations relevant to states of matter within planets.

• Acceleration and accumulation of high current ion beams.


Cosmic Particle Acceleration

γ-Astronomy gives evidence for several 100 TeV particle energies !

High Energy Stereoscopic System H.E.S.S., Namibia

γ-quants originate from particle-particle interactions close to the source of high energy protons(Cosmic Accelerator).

Identification of 3 source types:

- γ‘s from shock wave, originating from a former supernova explosion.

- γ‘s from pulsars within a former supernova explosion (e- e+ - generation and acceleration within shockwaves and rotating magnetic dipole field).

- γ‘s from our galactic centre (super massive black hole).C. v. Eldik, W. Hofmann, Physik Journal Jan. 2008


Linac Development

Aiming for high voltage gains per meter

Fowler-Nordheim eq. for rf-operation:

;/)/1(/)/(ln( 5.2 βkEdEId F −=

field emission current;=FI electric field;=Ematerial dependent;)(Φ= fk

field enhancement factor;=β

for ideal surfaces

;EEF ⋅= β

surfEE =

Typical β-range: 100 - 1000


Linac Development


Kilpatrick criterion for the limiting electric field E = V/g, gap width g

;64.15.8

2 EeEf−

⋅= MHzfmMVE /;//

14030250

12022001

10015063

809438

402122

20429

1070

57.5

E / MV/mf / MHz

GSI-HSI, 36 MHztoo pessimistic

DESY-Tesla, 1.3 GHzSLAC

too optimisticCERN CLIC-TF

Fit to experiments


S.C. Electron Linac Development

Examples: XFEL, s.c. elliptical cavities


S.C. Electron Linac Development


Accelerating gradient / MV/m

Achieved Q/E curves for Tesla cavities at DESY, D.Reschke et al.

At ~ 50 MV/m the magnetic field limit of Nb (~ 200 mT) is reached for the TESLA type cavity.


Ion Linac DevelopmentComparison with actually applied and / or prototyped

s.c. low energy structures

Legnaro-type QWR

Argonne-type QWR and HWR(with field asymmetry compensation)

Jülich, 3-Spoke, f = 760 MHz, β = 0.2

ANL, 3-Spoke, f = 345 MHz, β = 0.5


Ion Linac Development

S.C. low energy structure development at IAP Frankfurt

Cylindrical girder inserts :

• Easy e-beam welding.• Large frequency range.• Suited for tuning the gap voltage distribution.

β2006 = 350β2007 = 200


Superconducting CH Cavity Development

Incoupled (yellow), reflected (blue) andoutcoupled (pink) rf signal; 100 ms per div.

Quality factor against effective field gradient.

Status of measurements at IAP Frankfurt.

GSI Collaborations with Universities



• Expertise of IAP in linac design and construction.

r.t. IH-DTLW < 30 MeV30-250 MHz

r.t. CH-DTLW < 150 MeV150-700 MHz

s.c. CH-DTLW < 150 MeV150-700 MHz

copper plated steel bulk niobium

• IAP contributions to: GSI injectors, CERN Linac 3, Medical Injector Linacs

• Actual involvement in the development of a novel Proton Injector for GSI.


H-type DTL’s

Tloss

gain

seff lP

VZ

⋅=⋅

2

2cos φ

Shunt Impedances



CERN Linac 3, 33 MV, 1% duty cycle

101 / 202 MHz combination, in operation since 1994.

IH-Tank 2



High power tests on CERN Linac 3, IH-Tank 2

Surface fields up to 54 MV/m, eff. acceleration up to 10.7 MV/m


Beam Dynamics Code Development

Main issues and perspectives

1. Available elements

- rf gaps and cavities- radio frequency quadrupole (RFQ)- magnetic lenses (quadrupole, solenoid)- bending magnets

2. Field modeling

- hard edge models- analytic, approximate representations- field maps for rf gaps or magn. focusing elements

from numeric solvers


3. Space charge solver

- Direct particle-particle (PP) interaction- 2 D r-z (for radial symmetric distributions only)- 3 D PIC Poisson spectral solver with open or closed boundary conditions


Main issues and perspectives (continued)

x

y

z

ρ

0xL

zL

yL

x∆ j

z∆ly∆

k

Ω

x

y

z

ρ

Ω

lk

jr,

,

G

∞→=∂=Ω∂=

Rat

Gon

on

0

0

0

ϕϕϕ

possible cases:


4. Parallel processing

5. Number of simulation particles

- Up to 106 on scalar codes,mainly limited by efficiency of space charge calculation

- Up to 108 on high level parallel codes

6. Machine error simulation tools

- misalignment of focusing elements- rf tuning errors (single gaps or whole cavities)- ……


Main issues and perspectives (continued)



Code examples

openclosed

3D PIC FFTnoUnixIMPACT [iii]

closed3D PIC FFTapartUnixHALODYN [ii]

openPPnoWindows

UnixDYNAMION [i]

BoundarySpace charge

solverGUIPlatformCode name

[i] A. Kolomiets, V. Pershin, I. Vorobyov, S. Yaramishev, J. Klabunde,„DYNAMION – The Code for Beam Dynamics Simulations in High Current Ion Linac“Proc. of the 1998 EPAC Conf., Stockholm, p. 1201-1203.

[ii] A. Franchi, M. Comunian, A. Pisent, G. Turchetti, S. Rambaldi, A. Bazzani,„HALODYN: A 3D Poisson-Vlasov Code to Simulate the Space Charge Effects in the High Intensity TRASCO Linac“Proc. of the 2002 LINAC Conf., Gyeongju, p. 653-655.

[iii] J. Qiang, R. D. Ryne, S. Habib, V. Decykz,„An Object-Oriented Parallel Particle-in-Cell Code for Beam Dynamics Simulation in Linear Accelerators“J. Comput. Phys. 163, p. 434–451 (2000).



Code examples (continued)

openPP;

2D R-Z („SCHEFF“)yesWindowsPATH

open3D PIC („PICNIC“);2D R-Z („SCHEFF“)

apartWindowsPARTRAN [iii]

open3D PIC („PICNIC“);2D R-Z („SCHEFF“)

apartWindowsPARMILA [ii]

closed3D PIC FFTyesWindows

UnixLORASR [i]

BoundarySpace charge solverGUIPlatformCode name

[i] R. Tiede, G. Clemente, H. Podlech, U. Ratzinger, A. Sauer, S. Minaev„LORASR Code Development“Proc. of the 2006 EPAC Conf., Edinburgh, p. 2194-2196.

[ii] H. Takeda,„Parmila“Los Alamos National Laboratory Report, LA-UR-98-4478 (2005).

[iii] R. Duperrier, N. Pichoff, D. Uriot,„CEA Saclay Codes Review for High Intensities Linacs Computations“Proc. of the 2002 International Conference on Computational Science ICCS, Amsterdam, p. 411-418.



Flow chart for linac design

effective gap voltage values

drift tube array with transverse focusing

space charge action

check of field levels

drift tube structures and focusing elements

technical design


Linac Development

RF amplifier power limits


Ion Source Options

10 4 10 6 10 8 10 10 10 12 10 14

10 2

1

10

10 3

10 4

10 5

neτc /cm-3·s

Ee

/eV

SINGLY CHARGED IONS

HIGH CURRENT

MULTIPLY CHARGED IONS

MEDIUM CURRENT

HIGHLY CHARGED IONS

LOW CURRENT

Types :

ECRLASEREBIS

PENNINGLASER

MEVVACHORDIS

10 4 10 6 10 8 10 10 10 12 10 14

10 2

1

10

10 3

10 4

10 5

neτc /cm-3·s

Ee

/eV

SINGLY CHARGED IONS

HIGH CURRENT

MULTIPLY CHARGED IONS

MEDIUM CURRENT

HIGHLY CHARGED IONS

LOW CURRENT

Types :

ECRLASEREBIS

PENNINGLASER

MEVVACHORDIS


ECR Sources

20 25 30 35 40 45 50

1

10

100

1000 28 GHz SC-ECRIS (extrapolated) 28 GHz SERSE 18 GHz SERSE 18 GHz RT-ECRIS 14 GHz GSI-CAPRICE II

inte

nsity

(eµ

A)

Xe charge state

Ion Source Options


GSI-CAPRICE ECR Ion Source

7070Zn10+

5058Fe9+

4050Cr8+

8026Mg5+

Intensity

(eµA)Ion Species

7070Zn10+

5058Fe9+

4050Cr8+

8026Mg5+

Intensity

(eµA)Ion Species

Technical standard of 1990and status quo until now at GSI

Continuously improved oventechnology

M8

ЈЈ

Ј

14.5 GHzMICROWAVEIRON YOKE

IRON

PLASMA CHAMBER

ID 66 x 160 mm

IRONPUMP

HV BREAK

WINDOW

INSULATOR

HEXAPOLE

100 mm

OVEN

Ion Source Options


ECR Sources

The GyroSerse Project

Sectional View

Magnetic System

2150 mmL cryostat

1000 mmφ cryostat

700 mmL chamber

180 mmφ chamber

3.5 TB2(extraction)

4.5 TB1 (injection)

3 TBradial

10 kWMax. RF power

28-37 GHzFrequency

2150 mmL cryostat

1000 mmφ cryostat

700 mmL chamber

180 mmφ chamber

3.5 TB2(extraction)

4.5 TB1 (injection)

3 TBradial

10 kWMax. RF power

28-37 GHzFrequency

S. Gammino, private communication

Ion Source Options


Metal Vapor Vacuum Arc source MEVVA

Ion Source Options



Extracted beam current: 100 mA

Flat top: about 200 µs

Ion Source Options



Ion Source Options


Multi Cusp Ion Source MUCIS

Extracted beam current: 30 mA, Ar1+

Pulse length (HSI operation): 1 ms

Ion Source Options


W = 120 keV P = 2.4 x 10 W

b

b

4

Chopper f = 250 kHz

Steerer

Beam DumpDetector Development

high n - flux (dc)7Li Target

BunchCompressor

W = 1.87 - 2.1 MeVb

P = 2.1 x 10 Wb,max

4

DipoleMagnet

IH

W = 0.7 MeVb

P = 7 x 10 Wb,max

3

Chopper t = 50-100ns

f = 250kHz∆

Volume TypeIon Source

150 kVTerminal

Rebuncher

7Li Target

FRANZ Key Parameters

FRANZ Overview

• Extracted source current : 200 mA dc

• Pulsed beam target : 107 n / cm2s at l=0.8 m

• ‘Straight’ beam target : 108 n / cm2s


FRANZ Design and ConstructionIH-DTL acceleration with rebuncher for final energy adjustment

Resulting normalizedrms-emittance areas:

εx,rms = εy,rms = 1.4 mm mradεz,rms = 8 keV ns

RFQ IH tank RebuncherQuadrupole lens

10

-20

-10

0

20

0 0.2 Z, m0.4 0.6 0.8 1.0 1.2 1.4 1.6

Xm , ymmm

10

-20

-10

0

20

0 0.2 Z, m0.4 0.6 0.8 1.0 1.2 1.4 1.6

10

-20

-10

0

20

0 0.2 Z, m0.4 0.6 0.8 1.0 1.2 1.4 1.6

Xm , ymmm

30

-60

-30

0

60

0 0.2 Z, m0.4 0.6 0.8 1.0 1.2 1.4 1.6

∆Φm ,deg

30

-60

-30

0

60

0 0.2 Z, m0.4 0.6 0.8 1.0 1.2 1.4 1.6

30

-60

-30

0

60

0 0.2 Z, m0.4 0.6 0.8 1.0 1.2 1.4 1.6

∆Φm ,deg

95% Transverse Envelopes95% Transverse Envelopes

95% Longitudinal Envelope95% Longitudinal Envelope

I = 150 mA


FRANZ Design and ConstructionPulse structure

(LEBT)

At the targetafter bunch compressor: 1 ns, 4⋅1010 protons


FRANZ Design and ConstructionPulse structure, bunch compressor

Dipolmagnete

TargetmagnetischerChopper

Mobley-type scheme extended for high space charge load, will include rebunching in the symmetry plane.


FAIR Proton Linac

Parameter list and DTL layout

0.2Duty Factor [%]

4.2Norm. Transv. emittance [µm]

17Norm. Long. emittance [keV ns]

325.244Frequency [MHz]

4Repetition Rate [Hz]

36Beam Pulse Length [µs]

7.8Protons per Pulse [1012]

35 (70 design)Peak Current [mA]

70Output Energy [MeV]

30Length [m]


FAIR Proton Linac

Parameter list and layout of prototype cavity 2

3000Total Length [mm]

20Aperture [mm]

0.3Coupling Constant [%]

6.4 - 5.8Average E0T [MV/m]

60Effective Shunt Impedance [MΩ/m]

15300Q0-Value

1.35Heat Loss [MW]

882.6beam loading [kW]

11.7-24.3Energy range [MeV]

27 (13+14)No. of gaps


FAIR Proton Linac

Inter tank section with quadrupole lens


UNILAC Upgrade for FAIR

Present status: HSI and HLI into Alvarez section

High Duty Cycle RF-Operation of the GSI- High Charge State Injector (HLI) and the Alvarez-accelerator

Alvarez

Rebuncher

Presently:

duty factor (beam)= 25 % (rf: 35 %),A/ξ ≤ 8

Upgrade:

(new RFQ-structure, highercharge state from 28 GHz-ECR)

A/ξ ≤ 6.5, duty factor = 50 % (rf: 60 %)

Performance of all rf-tube-amplifiers([email protected] MW, IH+RFQ+Single Gap@200 kW, Rebuncher@ 4 kW) is sufficient to meet therequirements

Rebuncher

HSI

11.4 AMeV1.4 AMeV



Present status: HSI close to specifications for FAIR injection (20 mA U4+)



Mid and long term design options (together with W. Barth et. al., GSI)

Status Quo

HSI Stripper Alvarez ERs

SIS 18

HSI IH Stripper CH

SIS 18

HE-Linac

Ausbauoption

HSI IH Stripper CH1 CH2

SIS 90

SIS 18

Status Quo


SIS 18

HSI IH Stripper CH

SIS 18

HE-Linac

Ausbauoption


SIS 90

SIS 18

HSI IH Stripper CH

SIS 18

HSI IH Stripper CH

SIS 18

Hochladungs-cw-Injektor

Materialforschung/ISL

SHIP

TASCAX1HSI IH Stripper CH

SIS 18

HSI IH Stripper CH

SIS 18



SHIP

TASCAX1

Status Quo


SIS 18

HSI IH Stripper CH

SIS 18

HE-Linac

Ausbauoption


SIS 90

SIS 18

Status Quo


SIS 18

HSI IH Stripper CH

SIS 18

HE-Linac

Ausbauoption


SIS 90

SIS 18

Status Quo


SIS 18

HSI IH Stripper CH

SIS 18

HE-Linac

Ausbauoption


SIS 90

SIS 18

Status Quo


SIS 18

HSI IH Stripper CH

SIS 18

HE-Linac

Ausbauoption


SIS 90

SIS 18

Status Quo


SIS 18

HSI IH Stripper CH

SIS 18

HE-Linac

Ausbauoption


SIS 90

SIS 18

HSI IH Stripper CH

SIS 18

HSI IH Stripper CH

SIS 18



SHIP

TASCAX1HSI IH Stripper CH

SIS 18

HSI IH Stripper CH

SIS 18



SHIP

TASCAX1



3.5 – 7.3 CW-Linac design with 216 MHz s.c. CH cavities

Quadrupole triplet Solenoid Accelerating cavity

QT S1

B1 C1 C2 C3

Rebuncher

S2 S3

C4 C5

Variable part

C6 C7 C8 C9 B2

S5 S6 S7 S4

Diagnostics

0 5 10 15 Z, m

5

-5

0

Transverse envelope, mm

50

0

Longitudinal envelope; deg

-50

HLI



Equidistant gap structure EQUUS

cφ∆

ψm ψo

ψ, deg -900 -180 -270

0.01

-0.01

∆β

βs

Z βλ/40 βλ/2−βλ/4

Travelling waveEo,MV/m

7

-7

2

1



CW Linac design with a long cryostat



Related international activities

E=200 MeV/u

Pmax=400 kW

Spiral 2, GANIL, CaenFRIB, MSU, Michigan



Related international activities

Spiral 2, GANIL, CaenFRIB, MSU, Michigan


FAIR Facility


FAIR Facility

Superconducting magnets for fast rampingSIS100 Magnet R&D

Nuclotron Cable Nuclotron D ipole in Cryostat

Main R&D goal: Reduction of AC losses during ramping by improved i ron yoke design 40 W/m > 13 W/m B max= 2 T, dB/dt= 4T/s, f= 1 Hz

Window frame magnet with superconducting coil


FAIR Facility

Actual status, see new magazine “target”


Superconducting magnets for fast rampingSIS300 Magnet R&D (GSI/BNL – GSI/IHEP)

FAIR Facility

Rutherford cable RHIC dipole (4T) UNK dipole (6T)

Main R&D goal: Reduction of AC losses during ramping by improved c able and coil design

Efficient conductor cooling Bmax = 6 T – dB/dt = 1 T/s

(HERA: 4 mT/s, RHIC; 42 mT/s, LHC; 8 mT/s)

Cosθθθθ - magnet with a two layer coil


FAIR Facility

900Impedance seen by thebeam (Ω)

1,2; 0,8; 1,3Dimensions (l,b,h) (m)

890 ΩShuntimpedance RP

48 µHInductivity LP825 pFCapacity CP

235, => 12/Corecooling power (W)

Pulsed operationParameters

0,8Frequency (MHz)

40Gap-Voltage (kV)

5*10-4Duty Cycle

235Average Power (W)

1,8shunt impedance (kΏ )

(without final rf-stage)

900Impedance seen by thebeam (Ω)

1,2; 0,8; 1,3Dimensions (l,b,h) (m)

890 ΩShuntimpedance RP

48 µHInductivity LP825 pFCapacity CP

235, => 12/Corecooling power (W)

Pulsed operationParameters

0,8Frequency (MHz)

40Gap-Voltage (kV)

5*10-4Duty Cycle

235Average Power (W)

1,8shunt impedance (kΏ )

(without final rf-stage)

Compact Metglas cavities for smooth bunching and bunch compressionSIS 18 h=1 MA-cavity


Matching an CH-Linac to a 10 MeV Laser Driven Proton S ource

A. Almomani, U. Ratzinger, I.Hofmann

Experiments with PHELIX at GSI, M. Roth, TUD, et al.

Ex. opening angle 200

9.6... 10.4 MeV

60 mm maximum radiusspot ~ 8 mm (closer to lens)

Solenoid Ex. opening angle 200

9.6... 10.4 MeV


Solenoid Ex. opening angle 200

9.6... 10.4 MeV



CH-linac behind 10 MeV Laser Source, 95% - Transverse Envelopes, 20000 Particles

10 MeV ± 500 keV 20 MeV ± 450 keV,“Single Bunch”, 1010 Protons ≙≙≙≙ 500 mA !!


Transverse Cluster x-x’ and y-y’


Longitudinal Cluster


Emittance Growth


Summary and Outlook

- Improved conditions for accelerator development at Goethe-University Frankfurt – Riedberg; In house facility FRANZ under construction.

- Actually very intense international R&D activities on cw and pulsed ion linacs.

- Challenging code development for loss predictions along high power linacs.

- Fascinating accelerator facility FAIR, construction to be started!

- Quite attractive activities around FAIR, like the PHELIX driven proton source and the unique pulsed neutron source FRANZ.

Documents

High Current Ion Acceleration U.Ratzinger - DESYheraeus-technology.desy.de/e8/e44865/RatzingerIons.pdf · U. Ratzinger, Institute of Applied Physics (IAP), Goethe-University Frankfurt