Status of Vertical Tests of SSR1 Cavities A. Sukhanov for the - PowerPoint PPT Presentation

Status of Vertical Tests of SSR1 Cavities A. Sukhanov for the group of testers: T. Khabiboulline, D. Sergatskov, O. Melnychuk, Y. Pischalnikov, M. Hassan, L. Ristori, A. Rowe, I. Terechkine

Cavity Processing prior Vertical Test Allan Rowe 1. Incoming QC/QA a. Visual inspection • 4 weeks to process one cavity b. CMM c. RF QC • Few cavities can be processed in pipeline d. Vacuum leak check 2. US degreasing/UPW rinse 3. Bulk BCP (60+60 um) 4. US degreasing/UPW rinse 5. HPR in B101 to prepare for H 2 degassing 6. 600C bake 10h plateau in MP9 oven 7. RF tuning 8. US degreasing/UPW rinse 9. Light BCP (20-30 um) 10. HPR in G150 (horizontal) 11. HPR in B101 (vertical) 12. Cleanroom assembly 13. Evacuation/leak check (10 -10 mbar-l/s or better) 14. 120C vacuum bake in IB1 or MP9 120C ovens (24h hold minimum) 2

Cavity Processing prior Vertical Test Allan Rowe • 120C bake is beneficial for removing water from the cavity surface ‣ Shortens multipactor processing time during cold test ‣ Possible reduction of Q 0 by 30-40%? • Improvised 120C bake in IB1 using blankets and Al foil • ‣ 105,107,108 (1st test) & 109 TOP CAP JACKET #1 SKIRT FLAP DELRIN CLIP STRAP TYP + = TYP ZONE "A" SENSORS JACKET #2 PWR LDS CLOSING SEAM FLAP TYP TYP ZONE "B" SENSORS SKIRT FLAP JACKET #3 4" 4.2" 3

Cavity Processing prior Vertical Test Allan Rowe • 120C oven in MP9 ‣ 110 & 108 (2nd test) 4

Preparation of SSR1 Cavity for Vertical Test in IB1 Pictures courtesy of Dmitri Sergatskov Installation of the 2 nd sound system Cavity mounted on top plate Cage and P inc coupler 5

SSR1 Vertical Test Typical Sequence • Multipactor conditioning ‣ Usually at 4.4 K to save LHe • Cool-down from 4.4 K to 2 K ‣ Keep cavity on resonance at low field (3-5 MV/m) ‣ Measure df/dp and Q 0 vs T • Cavity performance evaluation at 2 K ‣ Q 0 vs E acc ‣ Maximum field, Q 0 and radiation at maximum field - approximate quench location w/ SS system ‣ FE (if present) onset field • Additional studies ‣ Induced quench studies (Dmitri & Iouri T.) 6

Multipactor Conditioning • S1H-NR-105 S1H-NR-105 (no 120C bake): March 27, 2012 (4.4K) Cleaned MP 14 after 3 h S1H-NR-105 (120C bake): April 16, 2012 (2K) S1H-NR-105 (HPR, 120C bake): June 23, 2012 (4.4K) 12 FE & MP are present after 6 h of processing Passed MP barrier , MV/m 10 after 3 h MP is present after 10 h ! 8 " / acc =V 6 acc E 4 2 0 00:00 02:00 04:00 06:00 08:00 10:00 Time elapsed, h 7

Multipactor Conditioning • S1H-NR-107 & S1H-NR-108 S1H-NR-107 : July 27, 2012 (4.4K) 14 S1H-NR-108 : October 30, 2012 (4.4K) S1H-NR-108 (HPR): January 16, 2013 (4.4K) 12 MP is present Cleaned MP after 9 h processing , MV/m after 3.5 h 10 ! 8 " / acc =V 6 acc E 4 Cleaned MP after 4 h 2 0 00:00 02:00 04:00 06:00 08:00 10:00 Time elapsed, h 8

Multipactor Conditioning • S1H-NR-109 & S1H-NR-110 S1H-NR-109 (HPR): November 13, 2012 (4.4K) 14 S1H-NR-110 (HPR): January 8, 2013 (4.4K) 12 Cleaned MP after 9 h , MV/m 10 ! 8 " / acc =V 6 acc E 4 MP is present after 11 h of processing 2 0 00:00 02:00 04:00 06:00 08:00 10:00 Time elapsed, h 9

Frequency vs Pressure, df/dp Measurements • Average df/dp is about -650 Hz/Torr at 2 K (unconstrained cavity) 0.4 S1H-NR-108, January 16, 2013: dF/dP = ( -683.1 1.9) Hz/Torr ± S1H-NR-108, November 1, 2012: dF/dP = ( -625.8 8.5) Hz/Torr ± S1H-NR-105, June 27, 2012: dF/dP = ( -451.8 5.6) Hz/Torr 0.3 ± S1H-NR-105, March 29, 2012: dF/dP = ( -645.4 1.9) Hz/Torr ± 0.2 f, MHz 0.1 ! 0 -0.1 -0.2 0 100 200 300 400 500 600 700 800 900 1000 LHe Pressure, Torr 10

Q 0 vs T Measurements • R s =G/Q 0 , G=84 Ohm for SSR1 80 C " Fit to: R (T) = R + exp - s T T 0 70 S1H-NR-108, November 1, 2012; R = ( 6.4 0.2) n ± ! 0 60 S1H-NR-105, June 27, 2012; R = ( 8.5 0.1) n ± ! 0 S1H-NR-105, March 29, 2012; R = ( 6.0 0.1) n ± ! 50 0 ! , n 40 s R 30 20 10 0 1 1.5 2 2.5 3 3.5 4 4.5 5 T, K 11

Q 0 and Radiation vs Field at 2K Q - solid marker, X-ray - empty marker 0 11 10 10 S1B-RK-102: March 3, 2009 S1H-NR-105: June 27, 2012 S1H-NR-107: July 30, 2012 S1H-NR-109: November 14, 2012 S1H-NR-108: January 16, 2013 PX specifications Radiation, mR/h 10 1 10 0 Q 9 -1 10 10 -2 10 0 5 10 15 20 25 E =V / , MV/m " ! acc acc 0 10 20 30 40 50 60 70 80 90 E , MV/m pk 0 20 40 60 80 100 120 140 B , mT pk 12

Q 0 at Low Field, 2K R 0*) , n Ω Cavity Test date Q 0 @ 3 Mv/m, × 10 10 S1H-NR-105 June 27, 2012 0.95 8.0 S1H-NR-107 July 30, 2012 1.02 7.4 S1H-NR-109 November 14, 2012 1.22 6.1 S1H-NR-108 January 16, 2013 1.54 4.7 *) we assume here that R BCS (2K) = 0.8 n Ω • Some gradual improvement in Q 0 (residual resistance) from earlier to later tests ‣ Improvement (or drift) in processing/preparation of cavities? 13

S1H-NR-110 Test Results at 2K • Q 0 ~ 1.3 × 10 10 at low field • Strong FE turn on at 8.5 MV/m • Maximum field achieved 13.7 MV/m (power limited) • Radiation ~1 mR/h • Observed excitation of 1588 MHz HOM (effective cavity length 135 mm) 14

Summary and Plans • Cavity processing procedure is established • 8 vertical tests of 5 SSR1 cavities ‣ 105 tested 3 times, 108 tested twice ‣ 4 cavities (105, 107, 108 & 109) qualified for PXIE cryomodule - observed some gradual improvement in Q 0 from earlier to last tests ‣ 110 performance limited by FE - optical inspection (using borescope) in clean room - RF measurements - (light BCP) - HPR - retest • Vertical tests of the rest of available SSR1 cavities ‣ 113 & 110 (March) ‣ 111, 112 & 114 (April-May) 15