L-band klystron development for the CLIC Drive Beam

1. L-band klystron development for the CLIC Drive Beam • Drive Beam klystron requirements • Optimization of parameters • Development and purchasing strategy and status

2. CLIC Layout at 3 TeV Drive Beam Generation Complex Main Beam Generation Complex

3. CLIC DB front end, Post CDR Project Modulator-klystrons, 1 GHz, 15 MW 500 MHz Diagnostics SHB 1-2-3 Gun PB Buncher Acc. Structures ~ 3 MeV ~ 12 MeV ~ 140 keV For time being only major component development: GUN, SHB, high bandwidth 500 MHz source, 1 GHZ MBK, modulator and fully loaded accelerating structure

4. CLIC Drive Beam requirements 3 TeV CLIC (CDR): 1638 klystrons, 15 MW, 150 ms, 50 Hz 24.57 GW peak power, 184 MW average 0.05 º intra bunch jitter, 0.2% amplitude 500 GeV about half the klystrons and factor 6 in beam power depending on scenario Main power ‘eater’ in CLIC (~50 % for 3 TeV)

5. CLIC Drive Beam optimization • Rebaselineing effort after the CDR with emphasis on low energy machine, cost and power consumption • Obviously drive beam and its power source in the focus • On the other hand need to fix some parameters to start developing hardware which takes a long time • Frequency dependence on cost and power consumption briefly studied • Linac cost studied as a function of klystron peak power

6. Parameter Studies, Frequency & Power

7. Frequency dependence Thales assuming constant power

8. Klystron cost model Ckl= 0.08 x V + 0.28 x I1/3 +0.2 x V1/2 + 0.1 +0.12 x P + 0.22 x V1/2P1/10 + t1/2.75 • RF circuit • Pulse length • Solenoid • Body • Collector • Gun • ⇨ Ckl = Ckl (Pk) • Fixing efficiency (=70%) and number of beamlets • Where Igor Syratchev, Roberto Corsini

9. Klystron cost vs peak power Klystron cost scaling with peak power Per MW Erk Erk h=0.5 Igor h~0.2+0.3xVoltage3 h=0.2 Per tube Igor Applying learning curves and lifetime evaluation Roberto Corsini

10. Total cost klystron/modulator Total cost of klystron/modulators units as a function of Pklystron [MCHF] Update, Davide’s model [MW] Roberto Corsini

11. Total Linac cost Total cost [GCHF] [GCHF] t [us] t [us] Pk [MW] Pk [MW] Roberto Corsini

12. Klystronparameters

13. State of the Art

14. State of the Art

15. State of the Art In terms of achieved RF efficiency, the klystrons with RF circuit adopted by Toshiba and CPI provides values very close to the 70%, as is specified in CLIC CDR (67.8% for CPI and 68.8% for Toshiba. These values validate the feasibility of a slightly higher efficiency with minimised design/fabrication efforts, when scaled in frequency down to 1.0 GHz. Igor Syratchev

16. Tentative klystron parameters Efficiency for 20 MW for different voltages (Thales study)

17. Parameter Studies

18. Status of the CLIC L-band klystron • Strategy: Try to develop prototypes with two different vendors to minimize technical and financial risk • Launched call for tender for design and prototype fabrication of such klystrons with the CLIC specifications • In parallel modulator development program in the power group • Frist contract signed with Thales ? • Preparing second one for next finance committee in March

19. Tentative Development schedule Thales

20. Klystron Test Stand Together with the Modulator team a test stand will be created to test the rf unit in detail with special emphasis on the stability measurements Structure test bunker Modulator MBK Acc Structure Load LLRF: Driver and Diagnostics Feedback ? Possible location: Bldg: 112

21. End

22. Parameter Studies