Input coupler assembly, high power and thermal performance in S1-Global at KEK E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing

Outline Introduction and QL of variable coupling Conditioning at room temperature High power performance and Inspection Measurement of dynamic heat load Summary S1-Global cryomodule installed in the STF tunnel E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing

Input Couplers in S1-Global Cryomodule AES004 ACC011 Z108 Z109 MHI-05 MHI-06 MHI-07 MHI-09 FNAL cavity DESY cavity KEK cavity Four STF-2 Coupler (KEK) Four TTF-III Couplers (DESY/FNAL) E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing

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

High Power System in S1-Global Cryomodule-A 4 KEK cavities (MHI-05, MHI-06, MHI-07, MHI-09) 4 STF-2 couplers (coaxial disk rf window, 60f ) Cryomodule-C FNAL (AES004, ACC011) cav. DESY (Z108, Z109) cavities 4 TTF-III couplers (cylindrical rf window, 40f ) E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing

RF Processing of Input Couplers Cryomodule-C /KLY#1 (2MW) Cryomodule-A /KLY#2 (5MW) 0.5 ms, 5 Hz, 500 kW 1.5 ms, 5 Hz, 200 kW Aug. 25 ~ Sept. 07 (10 days) E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing

RF Processing Time of Input Couplers at room temperature Cryomodule-A (STF-2 couplers) ave. processing time ~ 13 hours 20 hr Cryomodule-C (TTF-III couplers) ave. processing time ~ 21 hours 20 hr . Vacuum I/L ; 2.x10-4 Pa E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing

Operational RF power level for 8-cavity operation Stable operating Eacc (individual cavity operation) Calc. ave. Eacc C : 24 MV/m A : 28 MV/m C&A : 26 MV/m 0.5 ms 1.0 ms After warm-up to an intermediate temperature due to the trouble of cryogenic system, deterioration of vacuum pressure was suddenly occurred in A1 coupler, and operational RF power level was reduced. E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing

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

Inspection of TTF-III Couplers after Disassembly C1/ FNAL C2/ FNAL C3/ DESY C4/ DESY 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

Dynamic Loss Measurements in S1-G by N. Ohuchi (KEK) C-4 C-1 A-3 A-2 4 C Cavities 4 A Cavities 4 A Cavities 7 Cavities Date 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 Detuned Loss 0.09 W 0.18 W 0.7 W 1.8 W 1.2 W 0.5 W 4.6 W 0.2 W 2.5 W 1.6 W Dynamic Loss at Cavity 0.75W 1.26 W 2.0 W 2.9 W 1.3 W 4.4 W 7.0 W 3.2 W Q0 8.8E9 4.3E9 4.2E9 6.5E9 C1=22.2 C2=18.9 C3=14.9 C4=24.3 A1=15.8 A2=37.6 A3=32.9 A4=21.4 C1=25.2 C2=NA C3=17.6 C4=28.8 A1=15.3 A2=37.4 A3=32.4 A4=20.9 C1=20.1 C3=14.1 C4=23.0 A1=12.3 A2=30.4 A3=26.0 A4=16.7 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

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

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

Temperature Distribution around 5K in A2 Cavity E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing

Temperature Distribution around 80K in A1/A2 Cavity E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing

Further studies in STF-2 couplers 　Reduction of static loss 　Reduction of dynamic loss 　Efficient cooling by thermal anchor STF-2 input coupler for S1-G Two input couplers for QB-Cryomodule 0.8t SUS + Ni strike plating (0.2um) + Cu plating (3um) → Ni/Cu alloy (high R) Elimination of bellows (Coupler-B, 10um) (Coupler-A, 5um) Poor cooling to 5K → avoiding Ni-strike plating E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing

Sample tests of Cu plating on Au strike plating 1. Gold strike plating of 0.2 um and Cupper plating of 3 um on 0.8t SUS pipe 2. After 800 oC Heat Treatment 3. After 1st heat cycle to 4.2 K 4. After 2nd heat cycle to 4.2 K E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing

SUMMARY Four TTF-III input couplers and four STF-2 input couplers were successfully conditioned and operated at high RF power of 100~450 kW in S1-G cryomodule. Vacuum deterioration occurred in one STF-2 coupler. Disassembly troubles happened in two TTF-III couplers. Larger dynamic heat loads in STF-2 couplers than that in TTF-III couplers were observed. Improvements of RF losses in STF-2 couplers are under going. E. KAKO (KEK) 2011' Dec. 07 TTC meeting in Beijing

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

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