1. Dec/1/2015WG3 in TTC Meeting 2015 @SLAC1 Test Result of STF-2 Cryomodule Kirk Jun/2013Jul/2015 Preliminary

2. superconducting rf test facility Brief history of STF-2 project Dec/1/2015WG3 in TTC Meeting 2015 @SLAC 2 DateContent 2011 ~ 2013V.T. for 12 cavities Jun/2013Cleaning up STF tunnel Jul/2013 ~ Apr/2014Cavity string assembly (three times) Oct/2013 ~ Jan/2014Module assembly (CM1/CM2a) Jul/2014Final inspection for High pressure Gas Code Oct/2014 ~ Dec/20141 st cool-down / low power test Apr/2015 ~ Jul/2015Klystron / waveguide preparation Jul/2015 ~ Sep/2015Coupler conditioning at room temperature Oct/2015 ~ Dec/20152 nd cool-down / high power test High power test is still on-going, then every result is preliminary!

3. superconducting rf test facility Brief history of STF-2 project Dec/1/2015WG3 in TTC Meeting 2015 @SLAC 3

4. superconducting rf test facility Experimental devices for CM1/2a in STF-2 Dec/1/2015WG3 in TTC Meeting 2015 @SLAC 4 Radiation monitor Vacuum I/L module Vacuum gauge controller Arc I/L module Peak-hold module for electron Tuner remote controller Pulsed power meter Piezo high voltage DATA logger Oscilloscope Tuner controller

5. CM1CM2a MHI-18MHI-19 MHI-20 MHI-21 MHI-22 MHI-24 MHI-15MHI-14 STF-2 Cryomodule (CM1/CM2a) MHI-17 MHI-23 MHI-25MHI-26 BPM/Quadrupole Cavity string 1 (cavity #1-#4) Cavity string 2 (Cavity #5-#8) Cavity string 3 (Cavity #9-#12) Dec/1/2015WG3 in TTC Meeting 2015 @SLAC 5 Vacuum tank is common between CM1 and CM2a. We had to do the string assembly three times, because of the clean room capacity.

6. Capture CM CM1 CM2a MHI-12 MHI-13 MHI-18 MHI-19 MHI-20 MHI-21 MHI-22 MHI-24 MHI-15 MHI-14 STF-2 Accelerator Layout MHI-17 MHI-23 MHI-25 MHI-26 To be constructed in 2016 Cold box RF Gun Chicane Dec/1/2015WG3 in TTC Meeting 2015 @SLAC 6

7. superconducting rf test facility Cavity performance in CM test Dec/1/2015WG3 in TTC Meeting 2015 @SLAC 7 Module test is still on-going, then this result is preliminary! 31.5MV/m @Short 32.4MV/m @Full First and third cavity string achieved “No degradation” in CM test. At this time, Q 0 measurement is not done yet (next year). Second had significant trouble (heavy field emission) due to additional clean room work (probably). ILC TDR parameters (TDR Vol.3, Part II, p.24) Q L : 5.4 x 10 6 Filling time : 924μsec Flat-top : 727μsec Total width : 1650μsec STF-2 parameters Q L : 5.0 x 10 6 Filling time : 900μsec Flat-top : 800μsec Total width : 1700μsec String 1 String 2String 3

8. superconducting rf test facility Radiation level in CM test Dec/1/2015WG3 in TTC Meeting 2015 @SLAC 8 Module test is still on-going, then this result is preliminary! Short pulse (900+100μsec)Full pulse (900+800μsec) MAR-781/-782 Radiation level is measured below the cavity, upstream and downstream. Field emission is observed for every cavity. Especially, cavity #5, #6, #7 and #9 had heavy F.E. We will continue RF conditioning for cavity #6 after return to KEK.

9. Why performance degradation occurred? Dec/1/2015WG3 in TTC Meeting 2015 @SLAC 9 We used the local/temporary clean booth to connect each cavity string, because of the clean room capacity. But, we have done some irregular works for this connection. They might be causes for degradation. We missed the direction of the pumping port, then some parts conflicted each other.

10. Complete result will be released in IPAC16! Dec/1/2015WG3 in TTC Meeting 2015 @SLAC 9 Thank you very much for your attention