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renovation of the 200 MHz RF system. LLRF issues. Cavities redistribution. 2011 : 4 cavities 2 x 4 sections 2 x 5 sections + 3 spare sections. 2018 : 6 cavities 4 x 3 sections 2 x 4 sections + 1 spare section. Courtesy of Elena Shaposhnikova.
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renovation of the200 MHz RF system LLRF issues
Cavities redistribution • 2011 : 4 cavities 2 x 4 sections 2 x 5 sections + 3 spare sections • 2018 : 6 cavities 4 x 3 sections 2 x 4 sections + 1 spare section Courtesy of Elena Shaposhnikova 14th LIU-SPS Coordination Meeting
1.7 MW amplifier, i.e 1.4 MW cavity • To have 1.4 MW available at the cavity input, 1.7 MW at the Final output are needed • A major improvement to present systems would be to have individual SSA drivers per PA • Taking advantage of the long experience we have with tetrodes and combiners, the solution will be 16 x PAs combined through 3 dB combiners • Four contracts : • Drivers (SSA) • Finals (SSA or Tetrodes) • Combiners (3 dB above 100 kW) • Transmission lines (coaxial, 345 mm outer) From Beam Control 1/16 splitter Drivers 16 SSA Final 16 PAs 1.7 MW -0.6 dB total 3 dB combiners and power loads 1.5 MW 120 m and 180 m Coaxial lines -0.2 dB 1.4 MW To cavity input 120 m away 14th LIU-SPS Coordination Meeting
16 Tetrodesvs 2048 SSA • Tetrodes tube costs over 20 years will be added : • 20 years * 3/4 * 335 * 24 * 16 * 2 = 3’859’200 total hours • With 20’000 hours per tube = ~ 200 tubes • SSA : • + 20% to 25% additional transistors (not module) • Individual circulators are mandatory • Wall plug efficiency will be part of the adjudication • HVPS included (Tetrodes) • Losses in all SSA combiners, circulators and loads included 16 x 106 kW Tetrodes 16 x 128 x 830 W SSA 1.7 MW 14th LIU-SPS Coordination Meeting
First upgrade: Present amplifiers 14th LIU-SPS Coordination Meeting
More Power with Present amplifiers • Increase filament voltages : • Very expensive (562’000 CHF -> 1’111’000 CHF per year) • Effective efficiency not tested ! • Additional down time 14th LIU-SPS Coordination Meeting
More Power with Present amplifiers • HVPS Siemens improvements : • Full re-cabling • Air cooling modification • Philips amplifiers improvement : • Air cooling modification • ‘pre-modifications’ during next 2011-2012 Xmas stop to test new configuration during a MD in 2012 : • TX3 Siemens HVPS • TX5 Air cooling Siemens HVPS need a full re-cabling with new cable spacers Siemens HVPS need an air cooling improvement 14th LIU-SPS Coordination Meeting
More Power with Present amplifiers • Driver over coupled trick already used nowadays on all TXs • Maximum Power strongly proportional to BW • Driver over coupled trick already used nowadays on all TXs Pout [kW] BW -3dB [MHz] 14th LIU-SPS Coordination Meeting
Present amplifiers BW • The effective BW of the 1-Turn feedback is limited by • The TX gain BW: When the TX gain drops by ~ 20 dB, the overall loop has no more gain • The TX phase non-linearity: When the phase shift exceeds +-50 degree the overall loop gain must have dropped by more than 20 dB to keep the system stable • Conclusion: Good correction only in the band limited by +-30 deg phase non-linearity, and with an effectiveness that drops as the TX gain BW 14th LIU-SPS Coordination Meeting
BW specifications ? • New plan : • Present amplifiers connected to 3 sections cavities with higher bandwidth than 4 and 5 sections as per nowadays • New amplifiers connected to 5 sections cavities • What is the acceptable BW limit ? : • For ‘Siemens’ and ‘Philips’ • For new amplifiers • 2018 : 6 cavities 4 x 3 sections 2 x 4 sections + 1 spare section 14th LIU-SPS Coordination Meeting
Operation modes (on a match power load) 14th LIU-SPS Coordination Meeting
Operation modes (on a match power load) 14th LIU-SPS Coordination Meeting
New RF building • No more ‘Power’ in BB3 Faraday Cage • Specific ‘Power’ control room in new RF building, Cavity controllers, Conditioning systems, amplifiers monitoring • BB3-FC large enough for 6 systems ? 14th LIU-SPS Coordination Meeting
Draft schedule Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 2011 2012 2013 2018 2014 2015 2016 2017 Cavities re-arrangement within a LS ( > 6 months) RF : Studies (amplifiers, couplers, cavities, LLRF) Tendering (s) Build new hardware Install Commissioning Tunnel : Studies Build New hardware Installation phase 1 (pickups + dampers + EL + coax lines …) Installation phase 2 (cavities + pickups + CV + EL + vacuum) Building: Studies Authorizations Building Services Services 14th LIU-SPS Coordination Meeting
LLRF/Beam Control open issues ? • What is the acceptable lower BW limit ? : • For ‘Siemens’ and ‘Philips’ • For new amplifiers • Technical Specifications ? • BB3-FC large enough for 6 systems ? • Is a 3 sections cavity available in new RF building earlier useful ? • Is the draft schedule still correct ? • Time table • Resources • Money • How many time for commissioning without/with beam ? • What if LS2 earlier ? (later ?) • What else ? 14th LIU-SPS Coordination Meeting