ILC Interaction Point Intra-Train Feedback Kicker

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ILC Interaction PointIntra-Train FeedbackKicker

• November 1, 2005
• Steve Smith

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Layout/Requirements

• What kind of kicker and kicker driver are
  required for an ILC IP feedback?
• From the Oct. 4 BDS meeting
• Kicker 7 m from IP
• Space for kicker 1m
• Desire 100 s capture range (IP s)
• sy 5nm ? 500 nm capture range for the Y
  feedback
• sx 600nm ? limited to a few s capture range in
  X

Crossing Scheme R12 R34 Kicker Aperture
20 mradian 8.9 m 3.8 m 20 mm
2 mradian 16.4 m 4.7 m 180 mm
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Kickers

• Investigate two plausible solutions
• Unloaded stripline kicker
• Ferrite-loaded single-turn kicker.
• Both seem to be achievable.
• Many details are left out

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Unloaded Stripline Kicker

• XY kickers can coexist in the same structure.
• Assume four striplines
• each stripline covers 20 of the circumference.
• Electric field at the center E0 90Vstrip/R
• Y kick angle of q 500nm/3.8m 130 nanoradian
  kick.
• At p 250Gev/c ? 160 V max each stripline (20mr
  crossing)
• ? 1400 V max (2 mr
  crossing)
• Strip impedance 50 Ohms, ? 500W peak (20 mr)
• ? 35
  kW peak ! (2 mr)
• For lower stripline Z impedance, the current
  power go up.
• These drive requirement can be met.
• Example MOSFET driver proposed for the damping
  ring kickers requires 5 times the drive voltage
  and 100 times faster risetime
• But at the kV levels one should think of
  ferrite-loaded kickers to reduce the drive
  requirements.

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Ferrite Kicker

• Y and X kickers no longer coexisist
• must be at different zs.
• The model for a kicker is a single-turn ferrite
  loaded kicker.
• Assume a drive impedance of 12.5 Ohms.
• (without design or calculation)
• Use formulas for inductance and field that are
  appropriate for low gap height-to-width
• then apply to a kicker with hw so take the
  details with grains of salt.
• Needs a kicker designer

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20 mr Crossing Scheme Kicker
Parameter Value
Length 1 m
Turns 1
Gap height 20 mm
Gap width 40 mm
Impedance 25 Ohms
Max kick 130 nradians
Parameter Value
Current 2 Amps
Voltage 43 Volts
Power 75 Watt
Inductance 2.5 mH
Rise time 100 ns (L/Z)
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2 mr Crossing Scheme Kicker
Parameter Value
Length 1 m
Turns 1
Gap height 180 mm
Gap width 180 mm
Impedance 12.5 Ohms
Max kick 100 nradians
Parameter Value
Current 13 Amps
Voltage 300 Volts
Power 4 kW
Inductance 1.3 mH
Rise time 100 ns (L/Z)
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Mathcad Calculation
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Further simplification

• 300 ns is lots of time
• Forget matched transmission line
• Drive kicker as a shorted inductor.

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X Feedback

• Cannot deflect beam by q 60mm/10 m 6
  microradians in X.
• Can the capture range be reduced?
• Propose limiting x kick to a few times that of y
  kicker
• e.g. a few microns
• Get some help from ratio of R12/R34 2-3
• Use the same kicker design