1. Eiji Kako (KEK, Japan)TTC at Cornell, 2013 June 13 1 HOM absorbers; KEK HOM couplers in injector Eiji Kako (KEK, Japan)

2. 15 HOM Couplers 15 RF Feedthroughs Eiji Kako (KEK, Japan)TTC at Cornell, 2013 June 132 cERL Injector Cryomdule e - beam 0.5  5.5 MeV 10 mA

3. Eiji Kako (KEK, Japan)TTC at Cornell, 2013 June 133 OUTLINE 1. Design and RF measurements 2. RF feedthroughs 3. Vertical test results 4. Thermal anchors at 2K, 5K, 80K 5. Static temperature around HOM couplers 6. Dynamic temperature around HOM couplers 7. External Q of HOM couplers (filter) 8. Summary and next step

4. Eiji Kako (KEK, Japan)TTC at Cornell, 2013 June 134 Design and Measurement By K. Watanabe

5. Eiji Kako (KEK, Japan)TTC at Cornell, 2013 June 135 RF Feedthroughs By K. Watanabe Mo Cu Sus Cu Nb Al 2 O 3 Type-II’m (i.c: Mo, o.c: Cu) “male pin” Order for next, Type-III ; Al 2 O 3  Sapphire Sus flange  Ti

6. Eiji Kako (KEK, Japan)TTC at Cornell, 2013 June 136 Vertical tests with 5 RF feedthroughs

7. Eiji Kako (KEK, Japan)TTC at Cornell, 2013 June 137 Thermal Anchors at 2K (He-Jacket)

8. Eiji Kako (KEK, Japan)TTC at Cornell, 2013 June 138 Thermal Anchors at 5K and 80K 5K Panel 80K Shield Feedthrough (2K-Jaket)  5K Panel  80K shield  300K flange 15 HOM cables : 2.0 m + 2.0 m + 2.5m (Cu)

9. Eiji Kako (KEK, Japan)TTC at Cornell, 2013 June 139 Static Temperature around HOM Couplers (top/feed) HOM-1 HOM-2 HOM-3 HOM-4 HOM-5 Cavity 1 6.3 / 5.2 6.3 / 6.2 4.4 / 7.9 3.4 / 7.0 3.5 / 8.9 Cavity 2 3.3 / 6.5 3.6 / 6.1 4.4 / 7.7 3.7 / 6.3 3.7 / 5.7 Cavity 3 3.7 / 6.5 3.8 / 6.5 4.0 / 9.2 3.7 / 6.2 5.0 / 6.9 ave. T 4.4 / 6.1 4.6 / 6.2 4.2 / 8.1 3.6 / 6.5 4.1 / 7.1 HOM-1 HOM-2 HOM-3 HOM-4 HOM-5

10. Eiji Kako (KEK, Japan)TTC at Cornell, 2013 June 1310 Dynamic Temperature around HOM Couplers (1) Cavity -1 : CW Cavity -2 : CW 5.1MV/m 6.6MV/m 7.8MV/m Input-SUS Input-Nb HOM-top 7.5MV/m 5.0MV/m 9.2MV/m 6.6MV/m HOM- feedthrough HOM-top Input-SUS Input-Nb HOM- feedthrough

11. Eiji Kako (KEK, Japan)TTC at Cornell, 2013 June 1311 Dynamic Temperature around HOM Couplers (2) Cavity -2 : CW Input-SUS Input-Nb HOM-top 5MV/m Cavity -3 : CW HOM-top Cavity -3 : CW 8.1MV/m Input-SUS Input-Nb Quench HOM- feedthrough HOM- feedthrough

12. Eiji Kako (KEK, Japan)TTC at Cornell, 2013 June 1312 Dynamic Temperature around HOM Couplers (3) No.3 Cavity (50 ms, 2 Hz, 10%) No.3 Cavity (CW) HOM-1: 1.7 MV/m HOM-2: 2 MV/m HOM-3: 1.7 MV/m HOM-4: 5 MV/m HOM-5: 3 MV/m No.3 Cavity (10% Duty) HOM-1: 4 MV/m HOM-2: 6 MV/m HOM-3: 3 MV/m HOM-4: 15 MV/m HOM-5: 3 MV/m Eacc at antenna quench HOM- feedthrough HOM- feedthrough HOM-top

13. Eiji Kako (KEK, Japan)TTC at Cornell, 2013 June 1313 External Q of HOM Couplers (filter)

14. Eiji Kako (KEK, Japan)TTC at Cornell, 2013 June 1314 Summary and Next Step Excessive heating up at RF feedthroughs of HOM couplers was observed. This was caused by quench at the tip of Nb pick-up antenna. RF feedthrough will be replaced to new one with good thermal conductivity like sapphire. RF cables with smaller heat leaks and thermal anchors with efficient cooling will be investigated.

15. Eiji Kako (KEK, Japan)TTC at Cornell, 2013 June 1315 Thank you for your attentions. END