CIEMAT ACTIVITIES ON STRIPLINE KICKERS

I. Rodríguez

22

Outline

CTF3 Combiner Ring Kicker

CTF3 TL2 Tail Clippers

Stripline kickers in ILC

Conclusions

33

CTF3 Combiner Ring Kicker (1)

Kicker location in CTF3 Combiner Ring (CR)

Extraction of beam after 4-turns combination in the CR

Substitution of an old magnetic kicker to improve beam impedance

KICKER

44

CTF3 Combiner Ring Kicker (2)

Specifications to meet

±1% homogeneity is the most challenging specification

MAGNITUDE VALUE UNITS

Energy 300 MeV

Deflection Angle 8 mrad

Transverse voltage (V ) 2.4 MV

Rise/Fall-times (0-100%) ≤70 ns

Pulse length (max.) 200 ns

Flat-top reproducibility ±0.1 %

Flat-top stability (including droop) ±0.25 %

Repetition rate (Initial-Nominal) 5-50 Hz

Available length (flange to flange) 2000 mm

Vertical aperture ≥40 mm

Horizontal aperture ≥40 mm

Field homogeneity (±1%) 30 mm

55

CTF3 Combiner Ring Kicker (3)

Design and calculations Several cross sections considered. Planar electrodes

chosen

3D model in HFSS: 1.7 m electrodes. Good transmission of pulse frequency content

Wakefields studied using CST Particle Studio at CIEMAT and GDFidl at CERN

Aperture: 41 mmElectrode height: 44 mmTube radius: 54 mmBorder angle : 42ºBorder length : 8.2 mmElectrode width : 2 mmZ0 = 49.99 Ω

Homogeneity: ±0.74 %

|S11|2=<0.03% (0 to 50 MHz)

66

CTF3 Combiner Ring Kicker (4)

Manufacturing: Fully in stainless-steel Many high vacuum welds required

Challenging stand-off support Special beam pipe transitions

77

CTF3 Combiner Ring Kicker (5)

Testing Vacuum test and leak rate successful. Mild bake out

required High voltage pulser test: 16 kV, 5 ns, 50 Ohm load

DC high voltage test: 18 kV successfully tested (14 kV nominal)

RF tests

0 0.5 1 1.5 2 2.5 3 3.5

x 107

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1S11 at low frequency: 0.3 to 35 MHz

Almost no reflection < 0.2% in power up to 35 MHz

0 1 2 3 4 5 6 7 8 9 10

x 108

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1S11 low range: 0 to 1 GHz

0 5 10 15 20 25 30 35 40 45 50

0

0.2

0.4

0.6

0.8

Pulse directly to the load

Time (ns)

0 100 200 300 400 500 600 700 800 900 10000

0.02

0.04

0.06

0.08

Pulse frequency content

Frequency (MHz)

0 5 10 15 20 25 30 35 40 45 50

0

0.2

0.4

0.6

0.8

Pulse over first strip-line

Time (ns)

0 100 200 300 400 500 600 700 800 900 10000

0.02

0.04

0.06

0.08

Pulse frequency content

Frequency (MHz)

88

CTF3 TL2 Tail Clippers (1)

Tail Clippers location in CTF3

Shorten the bunch trains for conditioning before PETS

Extremely fast response required to precisely cut the beam between bunches

TAIL CLIPPERS

99

CTF3 TL2 Tail Clippers (2)

Specifications to meet

High frequency transmission is the most challenging specification

Beam energy 200 MeV

Total kick deflection angle 1.2 mrad

Deflection plane vertical

Stripline plate separation 40 mm

Field homogeneity ±20 %

Characteristic impedance 50 ±1 Ohms

Pulse duration (maximum) 200 ns

Maximum field rise-time (0.25 to 99.75%) 3 ns

Maximum timing jitter 1 ns

Pulse repetition rate – nominal/maximum 5 / 50 Hz

Number of stripline sections 4

Stripline section length (between centre's of feedthroughs) 300 mm

Total available straight section length 1625 mm

Pumping ports none

Supports and Alignment system as per CR kicker

1010

CTF3 TL2 Tail Clippers (3) Design and calculations

Several cross sections considered

Smooth coax to stripline transitions for enhanced RF transmission

Excellent high frequency transmission up to 2 GHz Homog:±19%

Ø 66 mmHomog:±15%Ø 71 mm

Homog:±10%Ø 78 mm

1111

CTF3 TL2 Tail Clippers (4) Manufacturing

Stainless steel tube and aluminium electrodes

Electrodes fully manufactured using CNC High voltage 50 Ohm feedthroughs Challenging coax to stripline connections

1212

CTF3 TL2 Tail Clippers (5)

Testing Excellent leak test. Good vacuum. Mild bake-out

required High voltage pulser test. Excellent behaviour at high

freqs

DC high voltage test: 3 kV successfully tested (2 kV nominal)

RF tests

0 100 200 300 400 500 600 700 800 900 10000

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1S parameters at medium frequency: 2 to 1000 MHz

Freq.(MHz)

S p

aram

eter

S11

S21

-1 0 1 2 3 4 5

x 10-7

-4000

-3000

-2000

-1000

0

1000

2000

3000

4000Pulse response of Tail Clipper 2 using 130 ns pulse

Time (s)

Vol

tage

-50 0 50 100 150 200 250 300 350 400 4500

1000

2000

3000

400020 ns pulse directly to the load

Time (ns)

0 20 40 60 80 100 120 140 160 180 2000

100

200

300Pulse frequency content

Frequency (MHz)

-50 0 50 100 150 200 250 300 350 400 4500

1000

2000

3000

400020 ns pulse passing through Strip2 of TailClipper 2

Time (ns)

0 20 40 60 80 100 120 140 160 180 2000

100

200

300Pulse frequency content

Frequency (MHz)

1313

ILC stripline kickers

Many stripline kickers in different zones: DRs, RTML, etc

Most challenging ones: Damping Ring injection and extraction kickers. DRs 6.7 km, 5 GeV.

The electrical pulser requirements are extremely challenging.

MAGNITUDE VALUE*

Number of modules in DRs

21 (injection)11 (extraction)

Length 0.3 m

Voltage ±11 kV

Bunch spacing 3 ns

Pulse width < 4 ns

Pulse repetition rate 150 ns (6.6 MHz)

* ILC Reference Design Report (August, 2007)

-1

0

1

2

3

4

5

6

-5 10-9 0 5 10-9 1 10-8

FID(FPG-3000M) Waveform

Volt

age(

kV

)

Time(s)

1414

Conclusions

Two stripline kickers have been fully designed, manufactured and tested. Tail Clipper power supplies were designed at CERN.

ILC kickers are very similar except from the pulsed power supply.