CORNELL ERL COUPLERS 1 COUPLER FOR ERL MAIN
- Slides: 12
CORNELL ERL COUPLERS: 1. COUPLER FOR ERL MAIN LINAC V. Veshcherevich Cornell University June 13, 2013 TTC Workshop 2013
ERL Main Linac Cavity Each 7 -cell cavity of the Cornell ERL Main Linac has one coupler June 13, 2013 TTC Workshop 2013 2
RF power and Qext requirements 10 RF power [W] 8 0 Hz 6 10 Hz 20 Hz 4 30 Hz 2 0 7 -cell cavity @16. 2 MV/m 40 Hz 6 10 7 10 8 Q 10 9 10 L RF power and Qext requirements are determined by microphonics (+ possible beam loss, beam return time errors, etc. ) June 13, 2013 TTC Workshop 2013 3
TTF-III Coupler as Prototype The design of the ERL Main Linac coupler is based on the design of classic TTF-III input coupler June 13, 2013 TTC Workshop 2013 4
Parameters of ERL Main Linac Coupler Operating frequency Maximum power (CW) June 13, 2013 1. 3 GHz 5 k. W Qext (fixed) 6. 5× 107 Cold coaxial line impedance 70 Ohm Warm coaxial line impedance 46 Ohm Cold coax line outer diameter 40 mm Warm coax line outer diameter 62 mm TTC Workshop 2013 5
Main Linac Coupler Challenges Main challenges for the linac coupler: Ø Mechanical flexibility to accommodate large movement (> 10 mm) of cold mass inside the cryomodule during the cool down Ø Minimizing cryogenic heat loads June 13, 2013 TTC Workshop 2013 6
ERL Main Linac Coupler W 650 Waveguide Flange Copper plating: 5μ Warm Ceramic Window 40 K Flange Cavity Flange (2 K) 40 K He Gas Cooling Air Cooling 300 K Flange Bellows Instrumentation Port Pump Port Antenna 5 K Intercept June 13, 2013 Cold Ceramic Window TTC Workshop 2013 7
Mechanical Flexibility Coupler has great flexibility for accommodating large movement (> 10 mm) of cold mass inside the cryomodule during the cool down. June 13, 2013 TTC Workshop 2013 8
ERL Main Linac Coupler: Main Parts 5 K Cooling Unit Waveguide Box Cold Coupler Warm Inner Conductor Warm Outer Conductor Air Cooling Socket June 13, 2013 TTC Workshop 2013 9
Heat Load on Cryogenics Heat Load for 5 k. W of RF power June 13, 2013 Static Heat Load Dynamic Heat Load Full Heat Load To 2 K 0. 05 W 0. 06 W 0. 11 W To 5 K 0. 64 W 0. 32 W 0. 96 W To 40 K 3. 78 W 5. 94 W 9. 72 W TTC Workshop 2013 10
Coupler Test Stand Termination Cavity Ion Pump RF Power from Transmitter Support Plate Coupler under Test June 13, 2013 TTC Workshop 2013 11
Coupler Performance Summary of the Main Linac coupler performance: Ø Two couplers have been fabricated by CPI, Beverly and tested at Cornell on the test stand up to 5 k. W CW. No major issues were noticed during the test. Ø One coupler was attached to the prototype linac cavity. The cavity was successfully tested (w/o beam) with great results achieved inside the horizontal test cryomodule (HTC). Ø Five more couplers are ordered for the Main Linac Cryomodule (MLC) Prototype. June 13, 2013 TTC Workshop 2013 12