# Input coupler assembly high power and thermal performance

- Slides: 21

Input coupler assembly, high power and thermal performance in S 1 -Global at KEK E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 1

Outline • • • Introduction and QL of variable coupling Conditioning at room temperature High power performance and Inspection Measurement of dynamic heat load Summary Measurement of dynamic heat load S 1 -Global cryomodule installed in the STF tunnel E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 2

Input Couplers in S 1 -Global Cryomodule C 1 C 2 AES 004 ACC 011 FNAL cavity C 3 C 4 Z 108 Z 109 DESY cavity Four TTF-III Couplers (DESY/FNAL) E. KAKO (KEK) 2011' Dec. 07 A 1 A 2 A 3 A 4 MHI-05 MHI-06 MHI-07 MHI-09 KEK cavity Four STF-2 Coupler (KEK) TTC meeting in Beijing 3

QL of Variable Input Coupler QL = 2. 4 x 106 D f bw = 542 Hz Cryomodule – A (STF-2 couplers) Cryomodule – C (TTF-III couplers) 2. 4 X 106 E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 4

High Power System in S 1 -Global Cryomodule-A 4 KEK cavities (MHI-05, MHI-06, MHI-07, MHI-09) 4 STF-2 couplers (coaxial disk rf window, 60 f ) Cryomodule-C FNAL (AES 004, ACC 011) cav. DESY (Z 108, Z 109) cavities 4 TTF-III couplers (cylindrical rf window, 40 f ) E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 5

RF Processing of Input Couplers Cryomodule-C /KLY#1 (2 MW) Cryomodule-A /KLY#2 (5 MW) 0. 5 ms, 5 Hz, 500 k. W 1. 5 ms, 5 Hz, 200 k. W Aug. 25 ~ Sept. 07 (10 days) E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 6

RF Processing Time of Input Couplers at room temperature Cryomodule-A (STF-2 couplers) ave. processing time ~ 13 hours Cryomodule-C (TTF-III couplers) 20 hr ave. processing time ~ 21 hours . Vacuum I/L ; 2. x 10 -4 Pa E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 7

Operational RF power level for 8 -cavity operation Stable operating Eacc (individual cavity operation) 0. 5 ms 1. 0 ms Calc. ave. Eacc C : 24 MV/m A : 28 MV/m C&A : 26 MV/m After warm-up to an intermediate temperature due to the trouble of cryogenic system, deterioration of vacuum pressure was suddenly occurred in A 1 coupler, and operational RF power level was reduced. E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 8

Inspection of STF-2 Couplers after Disassembly Cold couplers E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 9

Inspection of TTF-III Couplers after Disassembly C 1/ FNAL C 2/ FNAL C 3/ DESY C 4/ DESY 10 E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing

Calculated and Measured Static Heat Load by N. Ohuchi (KEK) E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 11

Dynamic Loss Measurements in S 1 -G by N. Ohuchi (KEK) C-4 C-1 A-3 A-2 4 C Cavities 4 A Cavities 4 C Cavities 4 A Cavities 7 Cavities Nov. 17 Nov. 19 Nov. 23 Nov. 24 Nov. 25 Nov. 26 Nov. 30 Dec. 2 Dec. 3 Dec. 9 Dec. 10 Gradient 28 MV/m 25. 2 MV/m 32. 3 MV/m 38 MV/m 32 MV/m Detune 20. 0 MV/m 26. 9 MV/m 25. 4 MV/m 20. 4 MV/m Dynamic Loss 0. 84 W 1. 44 W 2. 8 W 4. 8 W 2. 6 W 2. 7 W 6. 9 W 9. 6 W 4. 8 W Detuned Loss 0. 09 W 0. 18 W 0. 7 W 1. 8 W 1. 2 W 0. 2 W 2. 5 W 2. 6 W 1. 6 W Dynamic Loss at Cavity 0. 75 W 1. 26 W 2. 0 W 2. 9 W 1. 3 W 2. 5 W 4. 4 W 7. 0 W 3. 2 W Q 0 8. 8 E 9 4. 3 E 9 4. 2 E 9 6. 5 E 9 C 1=22. 2 C 2=18. 9 C 3=14. 9 C 4=24. 3 A 1=15. 8 A 2=37. 6 A 3=32. 9 A 4=21. 4 C 1=25. 2 C 2=NA C 3=17. 6 C 4=28. 8 A 1=15. 3 A 2=37. 4 A 3=32. 4 A 4=20. 9 C 1=20. 1 C 2=NA C 3=14. 1 C 4=23. 0 A 1=12. 3 A 2=30. 4 A 3=26. 0 A 4=16. 7 Date 0. 5 W 4. 6 W Dynamic losses of KEK couplers was 9 times larger than those of TTF-III couplers. E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 12

Dynamic RF Loss of TTF-III Input Couplers by N. Ohuchi (KEK) E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 13

Dynamic RF Loss of STF-2 Input Couplers by N. Ohuchi (KEK) E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 14

Temperature Distribution around 5 K in A 2 Cavity E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 15

Temperature Distribution around 80 K in A 1/A 2 Cavity E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 16

Further studies in STF-2 couplers n Reduction of static loss n Reduction of dynamic loss n Efficient cooling by thermal anchor STF-2 input coupler for S 1 -G Two input couplers for QB-Cryomodule 0. 8 t SUS + Ni strike plating (0. 2 um) + Cu plating (3 um) → Ni/Cu alloy (high R) Elimination of bellows (Coupler-B, 10 um) Poor cooling to 5 K E. KAKO (KEK) 2011' Dec. 07 (Coupler-A, 5 um) → avoiding Ni-strike plating TTC meeting in Beijing 17

Sample tests of Cu plating on Au strike plating 1. Gold strike plating of 0. 2 um and Cupper plating of 3 um on 0. 8 t SUS pipe 2. After 800 o. C Heat Treatment 3. After 1 st heat cycle to 4. 2 K E. KAKO (KEK) 2011' Dec. 07 4. After 2 nd heat cycle to 4. 2 K TTC meeting in Beijing 18

SUMMARY n Four TTF-III input couplers and four STF-2 input couplers were successfully conditioned and operated at high RF power of 100~450 k. W in S 1 -G cryomodule. n Vacuum deterioration occurred in one STF-2 coupler. n Disassembly troubles happened in two TTF-III couplers. n Larger dynamic heat loads in STF-2 couplers than that in TTF-III couplers were observed. n Improvements of RF losses in STF-2 couplers are under going. E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 19

END Thank you for your attentions ! E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 20

E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing 21