Funded by the European Union WP leaders meeting, CERN 3 and 4 December 2019 W. Wuensch, CERN WP4 Summary General observations: • RF system and module baseline established. Overall parameters fixed and consistent with other WPs, going forward with detailed design. • Long-range transverse wakes are being calculated for double bunch operation. • Harmonic linearizer 3 MW source baseline established. Full rf system including pulse compressor established. • Work started on industrialization of accelerating structures. • WP4 part of PBS OK. Cost estimate data OK.
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WP4 Summary · • WP4 part of PBS OK. Cost estimate data OK. Funded by the European Union WP leaders meeting, CERN 3 and 4 December 2019 W. Wuensch, CERN WP4 Summary WP4.1 status
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Funded by theEuropean Union
WP leaders meeting, CERN 3 and 4 December 2019 W. Wuensch, CERN
WP4 Summary
General observations:
• RF system and module baseline established. Overall parameters fixed and consistent with other WPs, going forward with detailed design.
• Long-range transverse wakes are being calculated for double bunch operation.• Harmonic linearizer 3 MW source baseline established. Full rf system including pulse
compressor established.• Work started on industrialization of accelerating structures.• WP4 part of PBS OK. Cost estimate data OK.
Funded by theEuropean Union
WP leaders meeting, CERN 3 and 4 December 2019 W. Wuensch, CERN
WP4 Summary
WP4.1 status
Linac RF design and optimization
Optimized X-band RF accelerating section designed on the base of specificationsprovided by other WPs, namely the average accelerating gradient (65 MV/m, WP2) andthe minimal average iris aperture of the cells (3.5 mm, WP6). State-of-the-art pulsecompressors have been included in the optimization.
Accelerating section design
The baseline accelerating section is TW type, 2π/3 phaseadvance, 90 cm long (108 cells) and shows a linearly taperediris aperture profile. A fine tuning of the entire structure toachieve the required field flatness is undergoing.
Complete model geometry and computed field distributionhave been transferred to WP6 for general beam dynamicsstudies and specific evaluations on BBU instabilities.
Funded by theEuropean Union
WP leaders meeting, CERN 3 and 4 December 2019 W. Wuensch, CERN
WP4 Summary
A baseline RF accelerating module has been defined for the Eupraxia@SparcLab project, consisting in 4structures powered by 1 RF klystron through a pulse compressor. This could be taken as a good reference forthe XLS module since the basic RF specifications are the same.
Two slightly different modules have been designed for the low-energy and high-energy linac sectors.
The module design has been based on a 50 MW, 1.5 µs, 100 Hz rep rate klystron (CPI VKX-8311A) capable todrive the 4 sections to the 65 MV/m nominal average gradient including a reasonable safety margin.
RF Accelerating module
WP4.1 status (cont’d)
Funded by theEuropean Union
WP leaders meeting, CERN 3 and 4 December 2019 W. Wuensch, CERN
WP4 Summary
Different scenarios have been considered to increase the operational rep rates towards the 1 kHz frontier at expense of a gradientreduction.
A first approach is based on the reduction of the RF pulse duration to the minimum allowed by the structure filling time (≈150 ns).250 Hz could be in principle reached but pulse compressors can not be used in this case.
A second approach is based on adding an additional RF power source to the module for high rep rate operation, which gives theoption of reaching 1 kHz at gradients larger than 30 MV/m.
Different linac configurations based on these modules are under considerations in collaboration with WP2.
High rep rate scenariosWP4.1 status (cont’d)
Funded by the
European Union
WP4, 1st August 2019 M. Aicheler, UH/HIP 3
Acc-Structure
Quad
103cm 12cm
Acc-Structure
Acc-Structure
Sector valve
10cm 5cm
Conn.
Baseline Module layout Low-Energy (up to 2 GeV)
Acc-Structure
Quad
Quad
Quad
Splitter
PC
Klystron/Modulator
Mode converters+ circular WG
100Hz@50MW1kHz@6MWPower
SwitchKlystron/Modulator
Module length: 5.10 m; RF-fill factor: 71%
Quad contains BPM&Corrector
Two WFM per AS with pumping
Funded by the
European Union
WP4, 1st August 2019 M. Aicheler, UH/HIP 5
Acc-Structure
Quad
103cm 12cm
Acc-Structure
Acc-Structure
Sector valve
10cm 5cm
Conn
103cm
Baseline Module layout Medium-Energy (up to 5.5 GeV)
Acc-Structure
Quad
Splitter
PC
Klystron/Modulator
Mode converters+ circular WG
100Hz@50MW1kHz@6MWPower
SwitchKlystron/Modulator
Module length: 4.76 m; RF-fill factor: 76%
5cm
Quad contains BPM&Corrector
Two WFM per AS with pumping
Funded by the
European Union
WP4, 1st August 2019 M. Aicheler, UH/HIP 5
Acc-Structure
103cm 12cm
Acc-Structure
Acc-Structure
Sector valve
10cm 5cm
Conn
103cm
Baseline Module layout High-Energy (up to 5.5 GeV)
Acc-Structure
Quad
Splitter
PC
Klystron/Modulator
Mode converters+ circular WG
100Hz@50MW1kHz@6MWPower
SwitchKlystron/Modulator
Module length: 4.59 m; RF-fill factor: 78%
Quad contains BPM&Corrector
Two WFM per AS with pumping
Funded by theEuropean Union
WP leaders meeting, CERN 3 and 4 December 2019 W. Wuensch, CERN
WP4 Summary
Task 4.3 Klystron and Modulator technologyInvestigating hardware choices for the three options of XLS linac and RF units Maintaining close contact with manufacturers to push for development of high rep rate tubes
Funded by theEuropean Union
WP leaders meeting, CERN 3 and 4 December 2019 W. Wuensch, CERN