Cavity Degradation Experience at S1-Global TTC Meeting 2011 @Beijing Kirk 7/Dec/2011

Outline Vertical test and Cryomodule test Performance improvement and degradation Optical inspection after S1-Global Summary 7/Dec/2011 TTC Meeting 2011 @Beijing

Vertical test and Cryomodule test CW operation Variable coupler with almost no reflection Several hundred W from RF Amplifier Cryomodule test Pulse operation (5Hz/1.5ms) Variable coupler with total reflection Several hundred kW from Klystron The duty factor is considerably different! 7/Dec/2011 TTC Meeting 2011 @Beijing

S1-Global Cryomodule Cryomodule-C Cryomodule-A (4 TESLA cavities) (4 TESLA-like cavities) 7/Dec/2011 TTC Meeting 2011 @Beijing

Cavity Performance @V.T. 2 cavities from FNAL 2 cavities from DESY 4 cavities from KEK 8 Cavities for S1-Global (ave. 30 MV/m) E. Kako 7/Dec/2011 TTC Meeting 2011 @Beijing

Cavity performance between V.T. and C.T. Ave. 30MV/m @V.T. Ave. 28MV/m @C.T. (single cavity) Ave. 26MV/m @C.T. (7 cavities) Two cavity performance was degraded and one cavity improved! 7/Dec/2011 TTC Meeting 2011 @Beijing

Cavity performance between V.T. and C.T. drastic improvement severe drop! 7/Dec/2011 TTC Meeting 2011 @Beijing

MHI#5 on 12/Nov/2010 In this day, we tried the LFD compensation by Piezo. But, before that, we had to adjust the F.B. tuning by LLRF system. During this adjustment, the F.B. parameter was not optimized, and abnormally input power had been supplied to this cavity. Therefore, the vacuum level was too high, and the vacuum interlock worked many times with the arc interlock! Cavity gradient 12:00 19:00 Vacuum at warm side He level He pressure He flow 7/Dec/2011 TTC Meeting 2011 @Beijing

Optical inspection for MHI#5 after S1-Global 7/Dec/2011 TTC Meeting 2011 @Beijing

Optical inspection for MHI#5 after S1-G 3rd V.T. @16/Apr/2009 π, 7π/9, 5π/9, 3π/9 @27.6MV/m 6cell equator, t=320 deg 4π/9, 6π/9 @30.7MV/m 5cell equator, t=154 deg 7/Dec/2011 TTC Meeting 2011 @Beijing

Transition of heating location for MHI#5 1st V.T. @4/Dec/2008 2nd V.T. @26/Feb/2009 3rd V.T. @16/Apr/2009 5π/9 (25.6MV/m) π, 7π/9, 5π/9, 3π/9 (27.6MV/m) 7π/9 (29.2MV/m) π, 3π/9 (~29.1MV/m) 4π/9 (20.4MV/m) 6π/9 (32.9MV/m?) 4π/9, 6π/9 (30.7MV/m) π, 8π/9, 4π/9, 3π/9 (~21.4MV/m) pre-EP : 5μm EP1 : 100+20μm EP2 : 50μm EP2 : 50μm EP2 : 20μm 7/Dec/2011 TTC Meeting 2011 @Beijing

History of defect at 154° in Cell#5 As received After EP1 25μm 7/Dec/2011 After EP1 100μm TTC Meeting 2011 @Beijing After anneal

History of defect at 154° in Cell#5 After EP2 and VT After 2nd EP2 and VT 7/Dec/2011 After S1-G TTC Meeting 2011 @Beijing

History of defect at 320° in Cell#6 As received After EP1 25μm 7/Dec/2011 After EP1 100μm TTC Meeting 2011 @Beijing After anneal

History of defect at 320° in Cell#6 After EP2 and VT After 2nd EP2 and VT 7/Dec/2011 After S1-G TTC Meeting 2011 @Beijing

Optical inspection for MHI#6 after S1-Global 7/Dec/2011 TTC Meeting 2011 @Beijing

Optical inspection for MHI#6 after S1-G 6th V.T. @16/Sep/2009 4-5 iris, t=255 deg. 3 cell equator , t=9 deg. 5π/9 (35MV/m) 6π/9 (35MV/m) 4π/9, 8π/9, π (28~32MV/m) 4 cell equator , t=103 deg. 7/Dec/2011 TTC Meeting 2011 @Beijing 8-9 iris, t=261~280 deg.

Profile of defect at 255° in Iris#4-5 4-5 iris, t=255 deg. Bump size 50×350[μm] 7/Dec/2011 TTC Meeting 2011 @Beijing

History of defect at 255° in Iris#4-5 As received After bulk EP After 1st VT After 2nd VT After 3rd VT After S1-G 7/Dec/2011 TTC Meeting 2011 @Beijing

History of defect at 261~280° in Iris#8-9 8-9 iris, t=261 deg. After 3rd VT After S1-G 8-9 iris, t=270 deg. After 3rd VT After S1-G 7/Dec/2011 TTC Meeting 2011 @Beijing

History of defect at 261~280° in Iris#8-9 8-9 iris, t=280 deg. After 3rd VT After S1-G 7/Dec/2011 TTC Meeting 2011 @Beijing

Optical inspection for MHI#7 after S1-Global 7/Dec/2011 TTC Meeting 2011 @Beijing

Optical inspection for MHI#7 after S1-G Top bp, t=324～350 deg. 2nd V.T. @15/Sep/2009 3, 5π/9 @35, 43MV/m Bottom bp, t=214～278 deg. No defect at every cell 6, 7, 8π/9, π @33~34MV/m Bottom bp, t=81 deg. 7/Dec/2011 TTC Meeting 2011 @Beijing

Problematic EBW at beam pipe 324° 333° 342° 350° 7/Dec/2011 TTC Meeting 2011 @Beijing

Problematic EBW at beam pipe Bottom bp, t=81 deg. Bottom bp, t=108 deg. Bottom bp, t=108 deg. 7/Dec/2011 TTC Meeting 2011 @Beijing

Problematic EBW at beam pipe Bottom bp, t=214～278 deg. 214° 223° 232° 242° 251° 261° 270° 278° 7/Dec/2011 TTC Meeting 2011 @Beijing

Optical inspection for MHI#9 after S1-Global 7/Dec/2011 TTC Meeting 2011 @Beijing

Optical inspection for MHI#9 after S1-G 3rd V.T. @16/Dec/2009 4π/9, π @27~28MV/m 2 cell equator , t=222 deg. 7, 8π/9, π @17~27MV/m 5, 6, 7, 8π/9, π @27~35MV/m 8-9 iris, t=94 deg. 9 cell equator , t=317 deg. 7/Dec/2011 TTC Meeting 2011 @Beijing

Transition of heating location for MHI#9 1st V.T. @3/Sep/2009 2nd V.T. @12/Nov/2009 3rd V.T. @16/Dec/2009 3, 4π/9 @28~29MV/m 1st π @27MV/m 3, 4, 5, 7, 8π/9, π @16~18MV/m 4π/9, π @27~28MV/m 5π/9 @39MV/m 7, 8π/9, π @17~27MV/m 7, 8π/9, 2nd π @25~34MV/m 6π/9 @40MV/m 5, 6, 7, 8π/9, π @27~35MV/m pre-EP : 5μm EP1 : 100μm EP2 : 20μm Ethanol+HWR+HPR EP2 : 20μm Degreasing(FM-20) +HWR+HPR EP2 : 20μm Degreasing(FM-20) +HWR+HPR 7/Dec/2011 TTC Meeting 2011 @Beijing

History of defect at 222° in Cell#2 As received After bulk EP After 1st VT After 2nd VT After S1-G 7/Dec/2011 TTC Meeting 2011 @Beijing

History of defect at 317° in Cell#9 As received After bulk EP After 1st VT After 2nd VT After S1-G 7/Dec/2011 TTC Meeting 2011 @Beijing

History of defect at 94° in Iris#8-9 As received After bulk EP After 1st VT After 2nd VT After S1-G 7/Dec/2011 TTC Meeting 2011 @Beijing

Summary DESY and FNAL cavities should be also inspected Two cavity performances were degraded at cryomodule test. MHI#5 cavity had coupler trouble due to non-optimized F.B. system. MHI#6 cavity improved largely because of lower duty factor. Every MHI cavity has several defects at equator, iris or beampipe. DESY and FNAL cavities should be also inspected by Kyoto camera after disassembly! 7/Dec/2011 TTC Meeting 2011 @Beijing

Thank you for your attention. 7/Dec/2011 TTC Meeting 2011 @Beijing