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M.J. Barnes CERN TE/ABT Also representing: Tony Fowler 1 , Gianfranco Ravida 1 , PowerPoint Presentation
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M.J. Barnes CERN TE/ABT Also representing: Tony Fowler 1 , Gianfranco Ravida 1 ,

M.J. Barnes CERN TE/ABT Also representing: Tony Fowler 1 , Gianfranco Ravida 1 ,

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M.J. Barnes CERN TE/ABT Also representing: Tony Fowler 1 , Gianfranco Ravida 1 ,

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  1. CTF3 Collaboration Technical Meeting TAIL-CLIPPER KICKER M.J. Barnes CERN TE/ABT Also representing: Tony Fowler1, Gianfranco Ravida1, Iker Rodríguez2 & Fernando Toral2 1 CERN 2 CIEMAT January 29, 2009

  2. OVERVIEW • Review of design and status of tail-clipper – several measurements presented; • Outstanding work for tail-clipper; • Future kicker systems that would be required for CLIC. January 29, 2009

  3. Extractionkicker Striplines installed Feb/Mar 2008 Tail Clipper Tail Clipper Hut (bat 6102) containing pulse generators Striplines Jan 2009 : kicker CTF3 Programme 2005 2004 Thermionic gun Linac DL CR 2006 2007 CLEX2007-2009 building in 2006 Photo injector / laser tests from 2006 TL2 2007 2007 30 GHz production (PETS line) and test stand January 29, 2009

  4. Jan. 2009 CTF3 & CLIC Stripline Kickers Generator 2007; Striplines 02/2008 January 29, 2009

  5. Beam Pulse The beam pulse extracted from the CR is 35 A and 140 ns. The tail-clipper must have a fast field rise-time, of 5 ns or less, to minimize uncontrolled beam loss. The flatness of the kick pulse is not important as deflected beam is to be thrown away. Schematic of Tail-Clipper Each pulse generator is composed of a 50Ω (Z) Pulse Forming Network (PFN), a fast semiconductor (Behlke) switch, 50 Ω stripline plates and a matched terminating resistor. Tail Clipper: Overview January 29, 2009

  6. 295mm Tail-Clipper Striplines (1) • Four sets of striplines. • Smooth transitions from coaxial feedthru to stripline. • Tapered electrodes preserving 50Ω characteristic impedance to minimize reflections. • At a radius of 10mm the deflection is up to 4.3% less than the on-axis deflection. • For an overall electrical length of 0.885m (3*0.295m), a current of ~53A into 50Ωprovides the specified kick of 1.2 mrad. • A 4th set of striplines provides redundancy. • “Over-driving” striplines also reduces field rise-time. 1.52m January 29, 2009

  7. Tail-Clipper Striplines (2) Pulse B in @ T0+1.27ns Pulse C in @ T0+2.54ns Pulse D in @ T0+3.80ns Pulse A to 50Ω Pulse A in @ T0 Pulse B to 50Ω Pulse C to 50Ω Pulse D to 50Ω BEAM from CR Pulse B to 50Ω Pulse D to 50Ω Pulse C to 50Ω Pulse A to 50Ω Pulse B in @ T0 + 1.27ns Pulse C in @ T0 + 2.54ns Pulse D in @ T0 + 3.80ns Pulse A in @ T0 1.2mrad deflection. Striplines fed from CLEX end. Pulse voltage: ±2.0kV for 1.18m; or ±2.65kV for 0.885m +ve: BEAM to DUMP (Collimator) 380mm (1.27ns) 295mm BEAM to CLEX -ve: January 29, 2009

  8. Virtual Ground +ve -ve Tail-Clipper Striplines (3) Measured pulse response with only one plate of a set of striplines driven: 2.87ns: 2 way delay of striplines & feedthrus Striplines in situ in TL2 Mismatch (S11=0.06): Z ≈ 56Ω. Impedance of 56Ω is due to only one-plate being driven (confirmed from simulations). To do: Double-check using a hybrid. January 29, 2009

  9. Tail Clipper: Block Diagram 2 x Current Transformers PFN: 50Ω, 170ns (+ve) [HTC-50-7-2] PFN: 50Ω, 170ns (−ve) [HTC-50-7-2] Coax: 50Ω, adjust delay (τP? &τN?) HTC-50-7-2: Coax, 50Ω, 10m 50Ω Terminator Behlke Switch HTC-50-7-2 HTC-50-7-2 Striplines TP1 τP1 SP1 BP1 PFN P1 TP2 τP2 SP2 BP2 Positive HV PS PFN P2 Positive HV distribution TP3 τP3 BP3 SP3 Timing In PFN P3 TP4 τP4 SP4 BP4 Control Unit PFN P4 GATE DRIVER PCB BEAM τN1 SN1 BN1 TN1 PFN N1 τN2 BN2 SN2 TN2 PFN N2 Negative HV distribution Negative HV PS Local τN3 BN3 SN3 TN3 PFN N3 To minimize relative jitter: same Gate Driver used for all 8 Behlke Switches. Remote τN4 SN4 TN4 BN4 PFN N4

  10. 10V Trigger from Gate Driver PCB Input Trigger (5V) To Load PFN Gate Driver PCB (9 Parallel 50Ω Outputs [8 Behlke Switches]) Previous measurements on Behlke switches show need for fast rising(few ns) trigger pulse ≥ 7V. Behlke Switch: Very Low Inductance Connections Tail-Clipper Hardware 9 Parallel 50Ω Outputs Peaking Capacitor January 29, 2009

  11. Meas. Waveforms: Normal Op. 5V Trigger Pulse 56A (53A [40A] reqd. for 3 [4] sets of striplines). Field rise-time of ~4.0ns [~3.2ns] predicted using PSpice (with td of 1.27ns), 0.25% to 99.75%, with measured current waveform, for 56A. Current in 50Ω load, 5.6kV PFN: (2.5ns rise 10% to 90%) Output of Gate Driver (2.5ns rise 0.5V to 7.5V) S/N 847409; 5x10pF Low noise within electronics & on trigger cable January 29, 2009

  12. Meas. Waveforms: S.Cct Load 5V Trigger Pulse Current in short-circuit load. ~104A amplitude (5.6kV PFN). (No significant reflections: 3 off DSEE-55-24N1F diodes, on HV board, terminate reflection from short-circuit). January 29, 2009

  13. “Top” CT to Control Room “Bottom” CT to Integrator or Local Diagnostics BACK VIEW Kicker Cabinet During Assembly 5 x Negative Polarity Switches 5 x Positive Polarity Switches HVPS Spare Switches January 29, 2009 FRONT VIEW

  14. Screen-Dump: Local Controls (courtesy of Jan Schipper) Diagnostics & Controls Four Channel Integrator Card, for “Online” Local Diagnostics January 29, 2009

  15. Tail-Clipper Status Striplines received at CERN early December 2008: • Shock detector activated during shipment !, but no problems apparent; • Impedance checked: 1 plate of a pair driven  56Ω (as per predictions); • HV pulses applied to striplines in air (6kV pulses to one plate at a time; ±5.6kV pulses to both plates of a stripline, simultaneously). No breakdowns; • Results from Jan Hansen, re vacuum: • Leak rate <1x10-10mbar•l/s; • 8.8x10-8mbar pressure on downstream gauge after 72 hours pumping; expected pressure in TL2 line of ~1x10-7mbar downstream of the kicker with the taper installed and using a standard CTF3 pumping port; • 3.4x10-9mbar pressure on downstream gauge 5 days after a 120°C bake out for 24 hours expected pressure in TL2 line of ~7x10-9mbar downstream of the kicker with the taper installed and using a standard CTF3 pumping port (no bake out of striplines foreseen in the machine). • Situated in TL2. • Fruitful collaboration with CIEMAT on BOTH TL2 Tail Clipper & CR Extraction kicker ! January 29, 2009

  16. Tail-Clipper Status & Ongoing Works • Tests on TL2 Pulse Generator: • show excellent (fast) rise-time; • system has been reliable • low noise levels within pulse generator. • Kicker cabinets installed in building 6102, January 2009. • Method developed to measure relative timing of Behlke Switches: method to be applied and, if necessary, relative timing modified. • Radiation will be higher than originally appreciated, therefore cable connecters with ceramic insulators ordered (to replace existing connecters with plastic insulators). • Cables between cabinets & striplines to be made, pulled & relative timing of pulses at striplines checked (before week 11 !!). • FID (Fast Ionization Dynistor) expected delivery in 2 months time!! – will be evaluated. January 29, 2009

  17. Future Kicker Requirements • DRIVE BEAM • Combiner Ring #1 Extraction (2.4GeV; ~830kHz burst rate for 63 pulses; 100Hz rep-rate; 240ns flattop; voltage may be very high?? – depending on aperture). • Combiner Ring #2 Extraction (2.4GeV; ~320kHz burst rate for 42 pulses; 100Hz rep-rate; 240ns flattop; voltage may be very high?? – depending on aperture). • Decelerating ring kickers (extraction into decelerating structure) – 42 systems!; Pulse to pulse stability may be important. • Phase feedback kickers (<100ns latency) – 96 kickers per side!. • MAIN BEAM • Injection and Extraction. Extraction requires a high stability flattop. • Inter-train feedback kickers at intersection points (pulse to pulse correction). 1TeV, 1nrad, <40ns latency (10ns preferred). • Beam Abort Kickers?? (e.g. 1 kicker per drive beam sector, 21st (final) kicker per side (1.5 TeV)  1T•m, 150Hz:R.W. Assmann, F. Zimmermann, “Efficient Collimation And Machine Protection For The Compact Linear Collider”, EPAC06). • DAMPING RING EXTRACTION • High precision (e.g. ±1x10-4), 2.9GeV, 50Hz, 160ns pulse width, 1μs rise & fall, ~5mm aperture. Table of preliminary parameters, for above, to be presented to kicker group, for discussion, in next couple of weeks ! – important for our input into CDR. January 29, 2009

  18. Questions ??? January 29, 2009

  19. Deflection due to Electric Field: Strip-line at positive voltage Fe From CTF3 CR Beam (e-) To CLEX Strip-line at negative voltage B B B B B B Deflection due to Magnetic Field: Strip-lines fed from CLEX end I +V Fm From CTF3 CR Beam (e-) To CLEX -V I Tail Clipper: Deflection January 29, 2009