CERN modulator outlook Pulsed High Power Modulators

1. CERN modulator outlookPulsed High Power Modulators 09/03/2010 CERN Pulsed Power Modulators

2. Modulators for LINAC4 (LP-SPL) (CERN) Rise time fall time time Flat-top Pulse width • Cathode power supply • Pulse width: 2.3 ms • Flat-top duration 2 ms • Rise/fall times (99% / 1%): 300µs • Repetition rate: 2 Hz • Nominal voltage: 110 kV • Nominal current: 50 A • Nominal power (peak): 5.5 MW • Average power: 23 kW • Flat-top droop: < 1% • HF ripple at flat-top: < 0.1% • Cooling: Air (natural or forced) • Maximum energy in case of arc: < 20 J 3MeV Teststand CERN Pulsed Power Modulators

3. Modulators for LINAC4 (LP-SPL) CERN Pulsed Power Modulators

4. Layout of the new injectors SPS PS2 ISOLDE PS SPL Linac4 CERN Pulsed Power Modulators

5. Layout of the new injectors CERN Pulsed Power Modulators

6. 180 MeV 5 GeV 50 MeV 643 MeV 3 MeV 102 MeV H- source RFQ DTL chopper CCDTL PIMS β=0.65 β=1.0 352.2 MHz 704.4 MHz HP-SPL Linac4 (160 MeV) SC-linac (5 GeV) Length: 540 m HP-SPL beam characteristics CERN Pulsed Power Modulators

7. Future Modulators for HP-SPL • Cathode power supply • Preliminary specification • Pulse width: 2.4 ms • Flat-top duration 2.1 ms • Rise/fall times (99% / 1%): 300µs • Repetition rate: 50 Hz • Nominal voltage: 110 kV • Nominal current: 30 A • Nominal power (peak): 3 MW • Average power: 360 kW • Flat-top droop: < 5% (1%) • HF ripple at flat-top: < 0.1% • Cooling: Air (natural or forced) • Maximum energy in case of arc: < 20 J Assumes 1.5 MW klystron with 50% efficiency The effect on RF power should be evaluated to find an optimum (1% is a typical design objective). CERN Pulsed Power Modulators

8. Future Modulators for ESS • Cathode power supply • (2 cavities/klystron preliminary values) • Pulse width: 2.4 ms • Flat-top duration 2.1 ms • Rise/fall times (99% / 1%): 300µs • Repetition rate: 20 Hz • Nominal voltage: 135 kV • Nominal current: 50 A • Nominal power (peak): 6.2 MW • Average power: 250 kW • Flat-top droop: < 3% ? • HF ripple at flat-top: < 0.1% ? • Cooling: Air (natural or forced) • Maximum energy in case of arc: < 20 J CERN Pulsed Power Modulators

9. CLIC Layout CERN Pulsed Power Modulators

10. Future Modulators for CLIC Rise time fall time time Flat-top Pulse width • Cathode power supply • Preliminary specification • Pulse width: <0.2 ms • Flat-top duration 0.15 ms • Rise/fall times (99% / 1%): <50µs • Repetition rate: 50 Hz • Nominal voltage: 150 kV • Nominal current: 150 A • Nominal power (peak): 23 MW • Average power: 175 kW • Flat-top droop: < 2% (1%) • HF ripple at flat-top: < 0.1% • Pulse to pulse stability: <0.001% • Cooling: Air (natural or forced) • Maximum energy in case of arc: < 20 J • Approximate quantity: 1500 Ability to run at 100Hz but same average power? Assumes 15 MW klystron with 65% efficiency The effect on RF power should be evaluated to find an optimum (1% is a typical design objective). CERN Pulsed Power Modulators

11. Future Modulators for CLIC CERN Pulsed Power Modulators

12. Future Modulators for CLIC CERN Pulsed Power Modulators

13. Modulators for SNS (LANL) Rise time fall time time Flat-top Pulse width • Cathode power supply • Pulse width: 1.6 ms • Repetition rate: 60 Hz • Nominal voltage: 140 kV • Nominal current: 70 A • Nominal power (peak): 9.8 MW • Average power: 980 kW • Flat-top droop: < 1% • HF ripple at flat-top: < 0.3% But accelerator works with >5% Vdroop and RF feedforward… CERN Pulsed Power Modulators

14. The SNS modulator (LANL) The Oak Ridge Nat Lab (SNS) type modulator, Bill Reass and Al. Los Alamos Lab AC/DC input converter not shown Several reliability issues. New design of some parts currently in progress. CERN Pulsed Power Modulators

15. Selected long-pulse modulators Preliminary figures CERN Pulsed Power Modulators

16. Definition of a voltage pulse Klystron: Energy deposited in case of quench <10J ‘pre-beam energy consumption’ PC + LLRF stabilisation time Fall time Beam time Rise time Droop (1 – 5% nominal) Klystron: -20% of nominal (max) time ‘Flat-top’ Pulse width Reset time Min repetition period CERN Pulsed Power Modulators

17. Key Unknowns • Technology • What is the best topology for a given application/pulse width? • What are the technology limitations (magnetics, switches, etc)? • Efficiency • How to get the best efficiency for usable output power? • Minimise rise times and system power losses? • Size (+ weight + layout) • What infrastructure is required? Can the system be split? Underground installation? • Cost • Initially first order cost is sufficient, with improving estimates as design is refined CERN Pulsed Power Modulators

18. CERN Modulator Requirements • CERN is currently constructing the first of 15 LINAC4 modulators • Some modulator projects dealing with high power levels, such as that required for HP-SPL, have experienced difficulties in their realization • CERN must further develop competence in high-power modulators that are compatible with future accelerator requirements CERN Pulsed Power Modulators

19. Modulator Roadmap • The CERN Electrical Power Converter group is starting a study on high-power modulators to investigate • Appropriate modulator technologies • Detailed design of critical sub-systems • Prototype evaluation of key sub-systems • Objectives • Propose well evaluated technical solutions for future accelerator requirements, in particular HP-SPL and CLIC • Provide estimates of cost, volume and other pertinent data • The project is structured such that a working modulator prototype for SPL or CLIC could be envisaged for ~2014 CERN Pulsed Power Modulators

20. Discussion objectives The objectives of the 2-day discussion • explore existing and new pulsed power topologies • agree the development directions • agree on the short-term objectives for 2010/2011 CERN Pulsed Power Modulators