ILC-BCD: Cavity PackageInternational Linear Collider - Baseline Configuration Document: Cavity Package

Lutz.Lilje@desy.de

DESY -MPY-

04/21/23 Lutz Lilje DESY -MPY-

Overview • Please look at:

– BCD Home• http://www.linearcollider.org/wiki/doku.php?id=bcd:bcd_home

– Main Linac• http://www.linearcollider.org/wiki/doku.php?

id=bcd:main_linac:main_linac_home

• Terminology– BCD: Baseline– ACD: Alternative configuration

04/21/23 Lutz Lilje DESY -MPY-

Cavity Package

• Cavity– Materials– Shape– Fabrication– Preparation

• Coupler• HOM Scheme• Tuner• Module

04/21/23 Lutz Lilje DESY -MPY-

Cavity• Materials– BCD: Fine grain– ACD: Large grain

• serious R&D effort recommended

• Shape– BCD: TESLA shape

• Very well know– ACD:

• Low-loss– serious R&D effort recommended

• Re-entrant– Multi-cell perceived to be difficult to prepare

• Superstructure– Would need superconducting seal as preparation for full unit is

perceived difficult» R&D effort recommended to develop seal

04/21/23 Lutz Lilje DESY -MPY-

Cavity (ctd.)

• Fabrication– BCD: Electron-beam welding– ACD: Hydroforming. Spinning

• Work on costing needed• Tube fabrication needs R&D

• Preparation– BCD: 800C furnace + EP + 120 C Bake

– serious R&D effort recommended

– ACD: 1400 C + EP´+ 120 C bake

04/21/23 Lutz Lilje DESY -MPY-

Coupler

• BCD: TTF III– Very well-known

• ACD:– Several ideas

• E.g. 2 KEK designs, LAL disk window

04/21/23 Lutz Lilje DESY -MPY-

HOM Scheme

• BCD: TESLA with minor mods + HOM absorber a la XFEL

• ACD: demountable rotationally symmetric couplers

04/21/23 Lutz Lilje DESY -MPY-

Tuner

• BCD: none

• ACD: – Blade– Saclay II

• XFEL choice• Would need modification for more compactness

– 2 KEK versions

04/21/23 Lutz Lilje DESY -MPY-

Module

• BCD: TTF III+ with modifications– Probably only 8 cavities

• Are 12 cavities really cheaper (less interconnects etc.)

– Quad at the center– Cavity spacing as small as possible

• BCD: 283 mm• Still need space for putting screws…..

• ACD– Movers on quad– Movers on module– Separate quad from cavity string and put in separate cryostat