1. The way to fast and "loss-free" SPS kickers E. Gaxiola With contributions from AB-BT-KSL section and F. Caspers, T. Kroyer, M. Timmins, J. Uythoven

2. Kicker Functional specification: Fast rise- and fall-time very stable magnetic field pulse Rise-, fall-times:200 ns to 1.1 μs Flattop ripple:0.5 to 1% Induction field0.08 to 0.16 T PS / SPS days – 13/01/2005 Limitations: Ferrite Curie temperature:Beam induced losses Beam impedance:Beam stability Maximum operating voltageSwitches Maximum currentFerrite core saturation B sat  Pulsed powerLow impedance travelling wave magnet  Speciality magnets* Vacuum; * High voltage; * High currents

3. Today’s kicker systems Upgraded thyratron switch performance Semiconductor components applications Heat conductance cooling Reduced beam impedance (longitudinal + transverse) Beam stability?!

4. Injection MKP 2001 4 batch LHC-type injection Modernisation/upgrade MKP systems #1 to #3 Impedance increase 12.5 Ω  16.7 Ω Faster rise time Improved flattop ripple PFN’s upgrade:Pulse fine tuning 2004 Rise time improvements for MKP system #4 2006 Final fine tuning (as was done for MKE)

5. Extraction MKE LSS4 2003 Magnet cooling for reduced beam induced heating Power semiconductor diode stacks  Increased reliability + lifetime (more cost efficient solution) from LHC MKD kicker generator development 2004 Shortened MKE Generator PFN lengths Optimized rise timePFN front cell adjustments + adjustable PFN first coil Reduced kicker rippleMagnet damping resistors Optimized fall timeMis-matched TMR values + Use of SPS transverse feedback system (tested in SPS MD)  CNGS double batch extraction practically within specs

6. The hardware limits of the present MKE kicker system are practically reached Oct 2003Step 1: As installed in 2003 July 2004Step 3: Mismatched TMR values Nov 2004Step 4: Fine-tuning adjustable PFN first coil for each MKE generator April 2004Step 2: Adding Magnet Damping Resistors + PFN front cell adjustments

7. Tune kicker MKQH Beam impedance reduction Test bench MKQH kicker magnet with ceramic inserts with resistive layer coating Proof of principle 2004  positive results for beam impedance

8. Approach I Not applicable to MKE:Due to significantly increased rise time! Alumina profile with Resistive coating

9. Results MKQH kicker magnet < 20042004 T * Curie reached at T MKE,reference =45ºC>90ºC Rise time 1-99%:0.6 µs2.9 µs

10. Results Impedance Measurements MKQH

11. Further improvements Studies underway Capacitive coupling by using metallic finger type strips:  Beam impedance reduction Im{Z} and Re{Z}  Reduced heating via Re{Z} 2006 Machine implementation on one MKE magnet (2 cells out of 7 cells) If successful:  Possible full 9 MKE fast extraction kicker upgrade LSS4 and LSS6 for 2007 and beyond (in e.g. shutdowns)

12. Approach II Bypass- insert: Double sided comb structure

13. Approach III Strips Printed Directly on Ferrites Interdigital comb structure 20mm spacing surface discharge

14. Results Impedance Measurements Single Kicker Cell (Approaches II and III)

15. MKE / MKQH kickers 2004 Lab:Significantly reduced beam impedance!  Reduced losses Next step(s): 2005 Study vacuum high voltage breakdown discharge characteristics Travelling wave kicker:To be X-checked 2006 SPS tests in LSS6

16. Summary Very useful knowledge build-up phase’98 – 2006 New kicker diagnostics were added over the past years. Tests for SPS ComplexApplication 2003 – 2008 Confirmation of the positive impact of the upgrade of the injectors for LHC “Old” recuperated equipment  Upgraded “modern” performance. This is only a preliminary summary of the findings. More extended analysis + documentation required. More detailed modelling  Compare measurements and simulations. Proven solutions  recommendations. CERN at the frontier: bigger and ….

17. Summary (continued) MKP:Rise time improvements done Further simulations + tuning to be done Higher reproducibility needed Spare to be finalized with increased diagnostics MKQH:Useful test-bed with proof of principle, not straight forward applicable to other kickers Beam impedance reduction realized MKE:Further tests to be done with stripes for voltage holding, vacuum, pulse shape in 2006 beam tests Larger scale applications in 2007 …. 2008 ? If not successful  New concept (Alternative new kickers, lots of $ + my) MKE pulse specs:After lots of modifications (not possible for 2003 tests) now practically at their limit together with damper practically fulfilling CNGS double batch specs (is damper use the definitive solution?)