2.1GHz cavity without cell-to-cell coupling slots – 1.875” beam pipe Binping Xiao Aug

Cavity overview No coupling slots between cells. Beam pipe aperture: cell to cell & end cell 1.875” Dimensions (cavity radius, FPC slot height, nose cones etc) are fine tuned. A = 1.875”A

Center cell (beta=1) h [mm]Rd [mm]f [GHz]Rsh [ohm]R/Q [ohm]QE-bound f [GHz]fh-fe[MHz] E E E E E E E

End cell aperture: radius in mm h2.5mm he0mm ∆L [mm]10(beta=1) r7 [mm]Rd [mm]f [GHz]Rsh [ohm] R/Q [ohm]Q E E E E r7 blending

3-cell Center cell h = 2.5 mm, cell radius: mm End cell h = 0 mm with 2 mm blending, cell radius: mm Fundamental mode: GHz, 6.69 MΩ shunt impedance, power on cavity W. Modes separation: GHz π/3 mode (+++), GHz 2π/3 mode (+0-), GHz π mode (+-+).

Tuner Lt [mm]f [GHz]R/Q [ohm]QQextQtuner Rsh [Mohm]QLPcavity [W]Ptuner [W] E E E E E

RF loss , R/Q [ohm] Voltage [V] MaterialQPower [W] standing wave power [W] 12.35E E E E E E E E E E E E E E E E E total power

And more Alumina window RF loss: 5 Watt (1.25 Watt for travelling wave) with 250 kV. Fixed tuner 3/8” dia, 5mm insertion, frequency increases 0.32 MHz. To compensate the possible Q-degradation brought by surface roughness or brazing. We choose FPC stub 50mm away from the bottom of the flat area on the "V" waveguide, assuming the cavity is 1cm in thickness, we can use 2.75" flange with 1.625" clearance, and 1.5" bolt with 1" dia thread and 10mm insertion. FPC stub position [mm]QextQFPCtuner No21989na E+08

Summary For the 2.1 GHz warm RF system: 3-cell cylindrical cavity with nose cones and without coupling slots is designed, and is optimized on shunt impedance. A vacuum pump will be attached to the cavity using a Tee on one of the beam pipe. Cavity is fine tuned for field flatness. Cavity performance at different tuners’ penetrations is evaluated. To do list: Error analysis, HOM modes up to 5 GHz, Pickup coupler.