Original title: Fast Timing & Kickers (WG2,6,7,8)

1. IWLC 2010 Wednesday afternoon Session 3 (S. Smith, B. Jeanneret) Original title:Fast Timing & Kickers (WG2,6,7,8) Perhaps more appropriate title:Drive Beam phase stability and feedback; kickers

3. Out of the five presentation, four directly address different aspects of the problem of how to monitor and control the phase of the Drive Beam. The fifth (Serrano’s) talks about the precise timing system which will be required to solve this problem.Barnes presentation also gives a complete overview of the different uses of kickers by CLIC, and on the specific problems related to each application.

4. CLIC Fine Timing System (Serrano) • A bit of background theory on phase noise and phase-locked loops • A look at the CLIC requirements and at available technologies • No solution presented yet • Work oriented at • Getting clearer specifications from users • Start evaluating promising technologies • Cost optimisation • Synchro over 25 km fiber links • For the time being, femtosecond timing over 25 km has not been done anywhere

5. The Drive Beam -> Main Beam synchronization feedback

6. Reminder of phase feed-forward concept 1 C.Perry – Oxford – 15 Oct 2010

7. Amplifiers (Burrows & Perry) • Requirements and assumptions • Speed: 10 ns • Kickers: stripline kickers 1 m long • 4 kickers per bend; deflection +/- 180µrad per kicker (but requirements are still changing) • Modular, MOSFET amplifier • Unusual very low duty factor (0.002%) • Main issues: Cost and Size • 250kW power amplifier per kicker • Amplifier size: 60x60x30cm (=100 litre) min (double is more realistic) • Amplifier cost (approx): £75K per amplifier • Total cost: £60 M (+/- 30?) (16x48 amplifiers, 200MW total peak power)

8. Other important issues for the amplifiers • Reliability (saving money by reducing reliability is not an option) • Fault Tolerance (capability of gently downgraded operation) • Maintenance (easy access is needed to replace small modules)

9. Kickers (Barnes, +Holma, Smith, Uythoven) • Very complete and detailed presentation, not possible to make a short summary • Drive Beam: • Combined Ring extraction kickers (4) (what about the delay loop?) • Main challenge: high burst rate • Turn Around kickers (48) • Phase Feedback Fast Kickers (192 (why not 768?)) • Main Beam • IP Fast Kicker • Damping Rings (PDR and DR, injection, extraction) • (Turn Around kickers for stray field compensation) • Analysis on sources of instabilitiesand errors • Double kicker system as a possible mitigation • MACHINE PROTECTION ISSUES (it goes without saying)

10. Consideration on the Conceptual Phase Stabilisation System (Schulte + others)

11. Again, it is not easy to summarize this talkin two minutes • The schema for the generation and transport of the DB trains to the PETS seems to have converged • Phase stability and tolerances: many things repeated from previous versions, plus a few changes (but, are the changes stable? Are the tolerance figures final?) • Two timing options left open (maybe in combination?) • Timing signal provided by main beam • Global timing system • Need for pulse-to-pulse feedback

12. The talk ended on an optimistic note, referring to results achieved at DESY (timing), and to measurements at CTF3 on • RF phase stability* • RF ampli stability* • Current stability * Do these results apply to all klystrons, or only to the best one?

13. Measurements on phase stability at CTF3 (Morpurgo, +Dubrovskiy) • Only parasitic measurements until now • One interesting measurement in TBTS: signal induced by the combined beam in the PETS

14. 10 degrees at 12 GHz == 2.5 picoseconds two “almost identical” pulses 36 seconds apart • These pictures clearly show the necessity • to make more specific measurements at CTF3 • to implement a femtosecond timing system and a more precise measurement system to be able to study these phenomena

15. Thank you