Lab Report TEMF - TU Darmstadt · 2004. 1. 21. · 4 TEMF, TU Darmstadt TESLA Meeting, DESY, Zeuthen, 01/21/04 Parameters used for Simulations (1) EAcc = 42 MV/m, ϕ= 33° •RF-Gun

Institut fürTheorie Elektromagnetischer Felder

TechnischeTechnische UniversitätUniversität Darmstadt, Darmstadt, FachbereichFachbereich ElektrotechnikElektrotechnik und und InformationstechnikInformationstechnikSchloßgartenstrSchloßgartenstr. 8, 64289 Darmstadt, Germany. 8, 64289 Darmstadt, Germanyweilandweiland@@temftemf..tutu--darmstadtdarmstadt.de, www.TEMF.de.de, www.TEMF.de

Lab ReportTEMF - TU DarmstadtW. Ackermann, R. Hampel, M. Kunze

T. Lau, W.F.O. Müller, S. Setzer, T. Weiland, I. Zagorodnov

TESLA Collaboration MeetingDESY, Zeuthen, 01/21/04

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4Outline

• Wakefield Simulations for the PITZ-Injector(W. Ackermann, S. Setzer)

• Wakefields in the 3rd Harmonic Structure (I. Zagorodnov)

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4Gun Layout

MAFIA

ASTRA

Handover

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4ASTRA to MAFIA Interface

• ASTRA♦ fast & efficient♦ no interaction between boundary and beam

• MAFIA♦ full set of Maxwells equations♦ interaction with surrounding structures♦ limited by cpu time & memory

z

z

Interface

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4Parameters used for Simulations (1)

AccE = 42 MV/m, = 33°ϕ

• RF-Gun Settings

zB 175 mT, z = 0.275 m=

• Solenoid Settings

These parameters resultin minimum

transverse emittance @ EMSY

Mag. Fluxdensity on axis

0.0 0.2 0.4 0.6 0.80

255075

100125150175

Bz(r

=0) /

mT

z / m

FWHM Rise

RMS

20 ps, 5 ps (Flat-Top)x,y = 0.5 mmQ = 1 nC

T T= =• Bunch Parameters

50.000 Macroparticles

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4Parameters used for Simulations (2)

Transverse Emittance calculated with ASTRA

0.0 0.5 1.0 1.5 2.00

5

10

15

x,y-

Em

ittan

ce / π

mm

-mra

d

z / m

EMSY

1.852

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4Interface Validation (1): Drift Tube

0.0 0.5 1.0 1.5 2.00.0

0.1

0.2

0.3

0.4

0.5 ASTRA (Complete run) MAFIA (Bunch from ASTRA) ASTRA (Bunch from MAFIA)

x-E

mitt

ance

/ π

mm

-mra

d

z / m

Zoom onnext slide

Comparison without Space Charge

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0.6 0.8 1.0 1.2 1.4 1.60.27

0.28

0.29

0.30

0.31 X-Emittance ASTRA Y-Emittance ASTRA X-Emittance MAFIA (Bunch from ASTRA) Y-Emittance MAFIA (Bunch from ASTRA) X-Emittance ASTRA (Bunch from MAFIA) Y-Emittance ASTRA (Bunch from MAFIA)

E

mitt

ance

/ π

mm

-mra

d

z / m

Comparison without Space Charge

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0.0 0.5 1.0 1.5 2.00

5

10

15 ASTRA (Complete run) MAFIA (Bunch from ASTRA) ASTRA (Bunch from MAFIA)

x-E

mitt

ance

/ π

mm

-mra

d

z / m

Zoom onnext slide

Comparison including Space Charge

30 cmTube

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0.6 0.8 1.0 1.2 1.4 1.61.5

2.0

2.5

3.0

3.5 X-Emittance ASTRA Y-Emittance ASTRA X-Emittance MAFIA (Bunch from ASTRA) Y-Emittance MAFIA (Bunch from ASTRA) X-Emittance ASTRA (Bunch from MAFIA) Y-Emittance ASTRA (Bunch from MAFIA)

Em

ittan

ce / π

mm

-mra

d

z / m

Comparison including Space Charge

Deviations caused by different space charge calculation methods

∆ε = 0.091 π mm mrad

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4Influence of Diagnostic Doublecross (1)

0.0 0.5 1.0 1.5 2.00

5

10

15 ASTRA (Up to diagnostic cross) MAFIA (Bunch from ASTRA) ASTRA (Bunch from MAFIA)

x-E

mitt

ance

/ π

mm

-mra

d

z / m

Cross without Mirror (0 mm Beam Offset)

Zoom onnext slide

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Cross without Mirror (0 mm Beam Offset)

0.079 π mm mradε∆ =

0.6 0.8 1.0 1.2 1.4 1.6

2.0

2.5

3.0 ASTRA (Up to diagnostic cross) MAFIA (Bunch from ASTRA) ASTRA (Bunch from MAFIA)

x-

Em

ittan

ce / π

mm

-mra

d

z / m

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4Influence of Laser Mirror

• Model of Laser Mirror

Laser

12.5 mm - offset 18.5 mm

Beam

x

z

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0.0 0.5 1.0 1.5 2.00

5

10


x-E

mitt

ance

/ π

mm

-mra

d

z / m

Cross with Mirror (0 mm Beam Offset)

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0.0 0.5 1.0 1.5 2.00

5

10


x-E

mitt

ance

/ π

mm

-mra

d

z / m


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0.0 0.5 1.0 1.5 2.00

5

10


x-E

mitt

ance

/ π

mm

-mra

d

z / m


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0.0 0.5 1.0 1.5 2.00

5

10


x-E

mitt

ance

/ π

mm

-mra

d

z / m


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0.0 0.5 1.0 1.5 2.00

5

10


x-E

mitt

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/ π

mm

-mra

d

z / m


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0.6 0.8 1.0 1.2 1.4 1.6

2.0

2.5

3.0

ASTRA MAFIA (Bunch from ASTRA) ASTRA (Bunch from MAFIA)

Diagnostic Cross, no Mirror

x-E

mitt

ance

/ π

mm

-mra

d

z / m

4 mm

0 mm1 mm

2 mm

3 mm

?

Summary: Influence of Beam Offset on x-Emittance

∆εx

= 0.

655 π

mm

mra

d

Influence of Diagnostic Doublecross (7)

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4 mm

0 mm

Summary: Influence of Beam Offset on y-Emittance

0.6 0.8 1.0 1.2 1.4 1.6

2.0

2.5

3.0

ASTRA MAFIA (Bunch from ASTRA) ASTRA (Bunch from MAFIA)

Diagnostic Cross, no Mirror

y-E

mitt

ance

/ π

mm

-mra

d

z / m

∆εy

= 0.

295 π

mm

mra

d

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4

• „ MAFIA ↔ ASTRA“ interface implemented♦ MAFIA TS3 bunch can be used as starting condition for ASTRA at

any position along the beam line (and vice versa)

♦ Validated by reference runs (with and without Space Charge)

• Simulation results♦ Optimal simulation parameters used

(min. emittance @ EMSY)

♦ Effect of the diagnostic doublecross on the transverse beam emittance @ EMSY (1.618 m) is about 0.08 π mm mmrad

♦ Effect of the laser mirror on the transverse beam emittance depends on the beam offset

♦ 4 mm Offset causes emittance growth @ EMSY∆εx = 0.655 π mm mrad ; ∆εy = 0.295 π mm mrad

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4Outline

• Wakefield Simulations for the PITZ-Injector(W. Ackermann, S. Setzer)

• Wakefields in the 3rd Harmonic Structure(I. Zagorodnov)

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4Wake functions of the3rd Harmonic Section

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4Geometry

1460 1470 1480 1490 1500 1510-4

-2

0

2

4

/z cm

/r cm

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4Long Range Wake Function

0 20 40 60 80 100

-100

-50

0

500

||

/W

V pC

/s cm0 5 10 15 200

0.5

1

1.5

2x 10130

||ZT Ω

/f G H z14

||1

2( ) 2 ( ) cos( )i ii

w s s K f scπθ

=

= ∑

1mmσ =

if /GHz 3.90 5.65 5.73 6.97 7.54 7.69 8.65

iK /(V/pC) 18.3 0.73 0.61 0.20 7.44 3.08 0.22

if , GHz 9.98 10.7 11.6 12.5 13.9 15.3 16.3

iK /(V/pC) 0.63 0.72 2.08 0.60 1.25 0.34 0.41

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4LOLA Cavity

σσyy

LOLA RF deflecting cavity to measure the bunch length at

the end of the linac

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4Wake Function of the LOLA Cavity

0 0.5 1 1.5 2 2.5-250

-200

-150

-100

-50

00

||

/WV pC

/s cm

1mmσ =

short range−

long range−

The short-range (dashed line) and long-range (dot-dashed line) longitudinal wake functions

Lab ReportTEMF - TU DarmstadtOutlineGun LayoutASTRA to MAFIA InterfaceParameters used for Simulations (1)Parameters used for Simulations (2)Interface Validation (1): Drift TubeInterface Validation (1): Drift TubeInterface Validation (2): Drift TubeInterface Validation (2): Drift TubeInfluence of Diagnostic Doublecross (1)Influence of Diagnostic Doublecross (1)Influence of Laser MirrorInfluence of Diagnostic Doublecross (2)Influence of Diagnostic Doublecross (3)Influence of Diagnostic Doublecross (4)Influence of Diagnostic Doublecross (5)Influence of Diagnostic Doublecross (6)Influence of Diagnostic Doublecross (7)Influence of Diagnostic Doublecross (8)OutlineWake functions of the3rd Harmonic SectionGeometryLong Range Wake FunctionLOLA CavityWake Function of the LOLA Cavity

Documents

Lab Report TEMF - TU Darmstadt · 2004. 1. 21. · 4 TEMF, TU Darmstadt TESLA Meeting, DESY, Zeuthen, 01/21/04 Parameters used for Simulations (1) EAcc = 42 MV/m, ϕ= 33° •RF-Gun