o. kester, jahrestagung des khuk, bad honnef, 30.11.2012 fair accelerator r&d oliver kester gsi...

O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012

FAIR accelerator R&D

Oliver KesterGSI Helmholtzzentrum für Schwerionenforschung

Darmstadt and

IAP Goethe-Universität Frankfurt


Outline

Introduction Challenges FAIR heavy ion accelerators Preparation of the injectors at GSI

Accelerator challenges and R&D High current ion sources Beam dynamics and cavities Injection / Extraction Cryomodules SIS100

Outlook

Introduction Challenges FAIR heavy ion accelerators Preparation of the injectors at GSI

Accelerator challenges and R&D High current ion sources Beam dynamics and cavities Injection / Extraction Cryomodules SIS100

Outlook


FAIR accelerator challenges

FLAIR

Superconducting magnets

Rf-cavities

Beam cooling

Diagnostic and XHV at highest intensities


UNILAC upgradeHigh power (high intensity),

short pulses Increase of beam brilliance (Beam

current / emittance) Increase of transported beam currents Improvements of high current beam

diagnostics / operation

SIS 18 upgradeFast ramping, enhanced intensity

per pulse Increase of injection acceptance Improvement of lifetime for low-

charged U-ions Increase of beam-intensity per time

due to reduction of SIS18- cycle time

Exchange of 35 years old Alverez accelerator

With modern interdigital H-type structures

Higher intensities 28 GHz ECRIS

Preparation of the injector chain


Filament driven Vacuum Arc driven

MUCIS, MUCIS New,

CHORDIS

MEVVA, VARIS

Working material:

Gases Metalls and Gases

High Duty factor

PIG

Metalls and Gases

GSI high current sources


VARIS (Vacuum Arc Ion Source)Optimized for Uranium (67% of 238U4+)

Emission current density

170 mA/cm2

156 mA @ 32 kV

55 mA @ 131 kV

20 mA in front of the RFQ

9 mA behind the RFQ

Vacuum Arc Driven Sources

Improving the beam quality at plasma extraction

Improvement of beam transport Lifetime of cathodes 3 Hz operation


UNILAC modifications and the HE-linac

Ion source and beam transport upgrade 4 Alvarez tanks, almost 40 years old exchange by modern IH-structures Charge state stripper technology higher charge states (high intensities) High intensity beam diagnostics

HLI

Stripper und Separator 1.4 MeV/u

ALVAREZ

MUCIS,

MEVVA

PIG


H-Mode Resonators for LINACs

E-Field

B-Field B-Field

E-Field

IH-Structure(interdigital H-type)

4-vane RFQIH-RFQ

CH-Structure(cross bar H-type)


The FAIR Proton Injector

Beam Energy

Beam Current (design/oper.)

Beam Pulse

Repetition Rate

Frequency

Norm. Emittance at output

Momentum Spread

Beam Loading (peak)

RF Power (peak)

Klystron (3 MW Peak Power)

Solid State Amplifier (50 kW)

Total Length (RFQ + CH)

70 MeV

70 / 35 mA

36 µs

4 Hz

325.224 MHz

2.1 / 4.2 µm

≤ ± 10-3

4.9 MW

2.5 MW

7

3

≈ 27 m

CH-DTL

Klystron


Charge state stripper for intense heavy ion beams

C-foil stripper

- short lifetime at highest intensities, but

highest charge states

gas stripper- High intensity capabilities, but lower

charge states

- Equilibrium charge state (efficiency)

10 m

mEdge of the foil before irradiation

Unused foil

Beam inBeam out Beam inBeam out

MIT Plasma window in a test setup at BNL

MIT Plasma window in a test setup at BNL

Plasma stripper- Need to increase the gas density – plasma

window for differential pumping

- Or dense plasma channel separated by

plasma windows


Emittance transferT

K3

QS

5

Co

il P

air

TK

3Q

D6

Ver. Chicane skewed triplet

• pepper pottriplet

H3+ 3p

Fo

il S

trip

pe

r

→

0.0

0.4

0.8

1.2

1.6

2.0

2002 2003 2004 2005 2006 2007 2008 2009

Year

Bea

m B

rilli

anz

[em

A /

µm]

hor. achieved (Ar) unstripped

hor. FAIR Design (U73+)ver. achieved (Ar) unstripped

ver. FAIR Design (U73+)

Future

Ex*Ey = const

Reminder:

Bx/y:= (q/A)*Current / Emittancex/y

emittance transfer from horizontalto vertical plane should help to increase the injection efficiency

transfer should preserve xy


The Synchrotron

QuadrupoleQuadrupole

Sextupole

bending

correction

focusing

Magnetic field and rf-frequency areramped synchronousto the particle energy.

Magnetic field and rf-frequency areramped synchronousto the particle energy.

MagnetsMagnets

Dipole

qvBr

mv

2


SIS100 169 high current (> 4 kA) quadrupolesSIS100 Injection/Extraction 4 low current (< 1 kA) quadrupoles

Main Characteristics of the SIS100 quadrupole:B‘ = 27 T/m, Effective length = 1,3 m

A modules comprises:

• two quadrupoles,• multipole corrector, steerer,

chromaticity sextupole• cryocollimator• beam position monitor (BPM)

Complex system concerning:• Girders, bus bars• helium headers• thermal shield, cryostat• vacuum chamber

SIS100 Quadrupole modules


Cold beam position monitorsIn SIS100 quadrupole modules

Signal transfer from 4 K levelto room temperature level

Cold BPMs

QDQD BPMBPM STST QDQD


Cryocatcher in Quadrupole Module

SIS100 Qaudrupole Cryostat L. Bozyk


Dynamic Vacuum effect and collimation

P. PuppelDipole

Target-Ionisation

Projectile-Ionisation

Coulomb-Scattering,Intra-Beam-Scattering

Desorption

adsorbed residual gas

U29+

Solid Body

Adsorbed Residual Gas

Desorbed Gas


0 10 20 30 40 50 60 70 80 90 1000.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

I E

SR

/

I SIS

t (s)

ptrans

t

circulating, cooled beam

rf-Barriers

Creation of a gap for injection of additional particles

New injected bunch

Cooling

Circulation time

Stacking of particles in the FAIR storage rings


Fast bunch rotation in the CR

Challenges:• Short bunch from SIS100 (50 ns)

• For stochastic cooling de-bunching required

• High voltage (200 kV) required for fast rotation and reduction of momentum spread after production target

Gap voltage 40 kV

Length 1 m

Rotation time ~ 100 s


Summary FAIR accelerator developments

High current ion sources and optimized beam transport

Cavity development for LINACS – H-type cavities

p-Linac and HE-Linac

Charge state stripper technologies

Emittance transfer – injection into synchrotrons

Cryogenic SIS100 modules and dynamic vacuum effect Accumulation of secondary particles via barrier

bucket injection

High current ion sources and optimized beam transport

Cavity development for LINACS – H-type cavities

p-Linac and HE-Linac

Charge state stripper technologies

Emittance transfer – injection into synchrotrons

Cryogenic SIS100 modules and dynamic vacuum effect Accumulation of secondary particles via barrier

bucket injection

o. kester, jahrestagung des khuk, bad honnef, 30.11.2012 fair accelerator r&d oliver kester gsi...

Documents

bad honnef

beam quality

bozyk slide

puppel slide

plasma windows slide

beam transport upgrade

hz operation slide

injector chain slide