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L-band klystron development for the CLIC Drive Beam. Drive Beam klystron requirements Optimization of parameters Development and purchasing strategy and status. CLIC Layout at 3 TeV. Drive Beam Generation Complex. Main Beam Generation Complex. CLIC DB front end, Post CDR Project.
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L-band klystron development for the CLIC Drive Beam • Drive Beam klystron requirements • Optimization of parameters • Development and purchasing strategy and status
CLIC Layout at 3 TeV Drive Beam Generation Complex Main Beam Generation Complex
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
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)
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
Frequency dependence Thales assuming constant power
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
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
Total cost klystron/modulator Total cost of klystron/modulators units as a function of Pklystron [MCHF] Update, Davide’s model [MW] Roberto Corsini
Total Linac cost Total cost [GCHF] [GCHF] t [us] t [us] Pk [MW] Pk [MW] Roberto Corsini
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
Tentative klystron parameters Efficiency for 20 MW for different voltages (Thales study)
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
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