Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker...

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Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction using strip-line kicker at ATF Preliminary test Magnets and power supplies for pulse bump Experiment plan T.Naito

description

Strip-line kicker system for ILC ~20 units for 0.6mrad kick angle

Transcript of Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker...

Page 1: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

Plan for Beam Extraction using strip-line kicker with pulse bump orbit

•Present extraction kicker system

•Strip-line kicker system for ILC

•Beam extraction using strip-line kicker at ATF

• Preliminary test

•Magnets and power supplies for pulse bump

•Experiment plan

T.Naito

Page 2: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

Septum MagnetExtraction Line

Damping Ring

Injected Beam

Extracted Beam

Extraction kicker(2nd kicker)

Damping Ring

Extraction kicker (1st kicker)

Injection kicker

L1 L2 L3 L4 L5 L6 L7 L8 L9 L10 L11 L12 Lec2 L13 L14 L15 L16Lec1

Damping Ring

S-band injector Linac

L0

KEK/ATF(Accelerator Test Facility) Beam Transport

Line

Extraction Line

Present beam extraction (Pulse magnet kicker system)

1st kicker2nd kicker

Beam

design orbit

extra kickΔθ1

Δθ2

Phase advance π

Kick angle Stability1x10-3 -> 2.8x10-4

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1↓

1↓

2 >

2 >

1) Ch1: 10 mV 50 ns

2) Ch1: 100 mV 50 ns Thy. Current 1 Amplitude Droop at 300ns

3 bunches, 154ns spacing

308ns pulse width

The number of bunches are limited.

Page 3: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

Strip-line kicker system for ILC

Delay Delay

TriggerSeptum

Delay

Circular beam orbit

Extracted beam orbit

DummyLoad

LBeam

stlip-line

d V

PPS-5kV

PPS+5kVDelay

Trigger

V

Delay

PPS : Pulse Power Supply

DummyLoad

~20 units for 0.6mrad kick angle

Δθ = 2g eVE

Ld

L = strip − line lengthd = distance between the electrodesV = pulse voltageE = Beam energy

g = tanh πω2d ⎛ ⎝ ⎜

⎞ ⎠ ⎟

ω = strip − line widthd = distance between the electrodes

Page 4: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

Design of Strip-line electrode for ILC

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The shape of the electrode is designed to keep good uniformity of the deflecting field. The calculated flatness is 0.07% in the area of +/-1.8mm from the center.

Max field2.0MV/m

1.27MV/m

Geometric factor(analytical) =0.955

Page 5: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

FID FPG5-3000M(1)

-1000

0

1000

2000

3000

4000

5000

-200 0 200 400 600 800 1000 1200Time(us)

FID FPG-3000M (3MHz, 3000 pulses)

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Burst pulses(3MHz, 3000pulses) droop : ~3%

Single pulse waveform

Page 6: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

FID FPG5-3000M(2)Pulse width(FWHM) = 2nsPulse height = 5.8kVRise time = 1.5ns(5%~95%)Time jitter = 29psAmplitude jitter = 0.72%(limited by the scope resolution)

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Timing jitter measurement29ps(1s)

Amplitude jitter measurement0.72%(1s)

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Page 7: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

Beam kick experiment at ATF-DR

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Single unit of strip-line kicker

DummyLoad

LBeam

stlip-line

d V

PPS+5kV

DummyLoad

DelayTrigger

The kick effect of the single strip-line kicker was measured by measuring the amplitude of the betatron oscillation in the ring. A turn-by-turn BPM system was used for the measurement of the betatron oscillation.

Page 8: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

Timing scan of the kick pulse

Rise time = 3.2ns(1%~100%)Fall time = 4.0ns(100%~1%)

Beam kick profile measurementThe timing of the kick pulse is scanned for the timing of the beam with 200ps steps.

The kick angle is estimated from the amplitude of the betatron frequency of the FFT signal.

Page 9: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

Septum MagnetExtraction Line

Damping Ring

Injected Beam

Extracted Beam

Extraction kicker(2nd kicker)

Damping Ring

Extraction kicker (1st kicker)

Injection kicker

L1 L2 L3 L4 L5 L6 L7 L8 L9 L10 L11 L12 Lec2 L13 L14 L15 L16Lec1

Damping Ring

S-band injector Linac

L0

KEK/ATF(Accelerator Test Facility) Beam Transport

Line

Extraction Line

Location of strip-line kicker

Strip-line kicker

The bunch spacing in extraction line does not completely the same interval. A 2.8ns( or 5.6 ns) is added at every three bunches, for example, 154ns, 154ns, 154ns, 156.8ns, 154ns . . . .

The extraction pulse magnet is replaced by two units of strip-line kickers. Three cycles of the injected beam, which include up to 60 bunches, are extracted bunch-by-bunch with 154ns (or 308ns) spacing.

Page 10: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

Strip-line electrode and pulser for ATF beam extraction

Electrode distance:12mmChamber diameter : 24mmImpedance :50ohmMax field at 10kV : 4.7MV/m

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FID developed 6MHz burst,7kV peak pulser.

Page 11: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

A 60cm long kicker magnet makes a 4.6mrad kick angle. Two strip-line kickers can make only1.3mrad kick angle. It is not enough for the kick angle to extract the beam.

Replacement plan from kicker magnet to strip-line kicker

Page 12: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

Beam extraction design with two strip-line kicker

The kick angle of the strip-line kicker is not enough to make the beam extraction orbit. A design uses pulse bump magnets and an auxiliary septum magnet, which has thin separator, to help in making the extraction orbit. This design makes a bump orbit after the beam damping, then the selected beam is extracted bunch-by-bunch by the strip-line kicker.

Page 13: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

Timing chart of 60(30) bunches beam extractionThe bump orbit is gradually increased after all of the bunches have been damped. The strip-line kicker kicks out the beams at the timing of the flat-top of the bump orbit. The beams are extracted as one long bunch train, which is a 10micro-sec long with 154ns (or 308 ns) spacing.

Page 14: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

Local bump test by using present magnets and DC power supplies(1)

The aperture survey was carried out by using present magnets and DC power supplies. The required bump height is 5mm to separate the extraction beam and the circular beam. However, the local bump could make only +4mm and -2mm height.

Page 15: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

Local bump test by using present magnets and DC power supplies(2)

Bump height

The measurement has agreed with the optics settings. The aperture limit at +4mm and -2mm are assumed that the limits show the miss-alignment of the septum or a large orbit distortion at the location.

Page 16: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

Beam extraction design with two strip-line

The bump orbit is optimized to eliminate the aperture limit at the septum area. This design has no orbit change at the septum area, however the bending angle of the bump magnets is increased.

Bump orbit

Page 17: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

Required magnet parameters

1. Magnets(not yet designed)• Steering magnets

• Bending angle: 9mrad(max)• Effective length 100mm• 0.4T(max)

• Septum magnet • Bending angle: 14mrad• 1000AT, 0.6m, 1 turn coil

2. Power supplies• Steering magnets - 50A(MAX), 10V(pulse)• Septum magnet - 1000A, 1V(DC)

Page 18: Plan for Beam Extraction using strip-line kicker with pulse bump orbit Present extraction kicker system Strip-line kicker system for ILC Beam extraction.

Proposed Schedule

•10kV fast pulser order and test Summer 2007

•Fabrication strip-line electrodes Fall 2007

•Fabrication bump magnets and pulse PS Summer 2007

•Pulse bump magnet test Fall 2007

•Fabrication Septum magnet Fall 2007 -

•Installation strip-line electrodes and septum Spring 2008

•Beam test Spring 2008