Helium Processing Progress M. Drury SRF
Schedule vs. Actual Actual Schedule Zone Baseline Meas He Proc Cryocycle Post Proc Meas Baseline Meas He Proc Cryocycle Post Proc Meas 1L02 2L02 2L03 2L04 75 2L05 2L06 100 100 2L07 100 100 100 100 2L08 2L09 2L10 2L11 100 100 2L12 100 100 100 100 100 100 100 2L13 2L14 2L15 2L16 100 100 100 2L17 2L18 100 100 100 100 2L19 2L20 2L21 1L22 2L22 2L23 25 2L24 2L25 100 2L26 Thomas Jefferson National Accelerator Facility Page 2 TTC 14
Gain in Field Emission Free Voltage (MV) Zone Integrated Change FE Gradient (MV) 1L02 5.7 2L02 2L03 2L04 2L05 2L06 2L07 5.3 2L08 5.0 2L09 2L10 2L11 2L12 3.9 2L13 3.4 2L14 2L15 2L16 2L17 2.5 2L18 2L19 C20 /C50 Average Gain 3.9 2L20 1.6 2L21 1L22 7.14 2L22 2L23 2L24 2L25 11.3 8.2 2L26 6.2 C100 Average Gain 5.2 Overall Average Gain Thomas Jefferson National Accelerator Facility Page 3 TTC 14
Distribution of FE Onset Deltas 12 Includes 1L02 and 1L22 – Processed in Jan 2015 10 Average Change = 1.1 MV/m 8 Frequency 6 4 2 0 -1.5 -1.1 -0.7 -0.3 0.1 0.5 0.9 1.3 1.7 2.1 2.5 2.9 3.3 3.7 4.1 4.5 4.9 Change in FE Onset (MV/m) Thomas Jefferson National Accelerator Facility Page 4 TTC 14
GM Tube Locations BL BL Top Center Ret Sup WG2 WG8 WG4/5 WG1 WG3 WG6 WG7 WG30 WG40 BL BL Top Center Sup Ret WG50 WG20 WG tubes and Top Center = Radial BL Supply and Return = BL Thomas Jefferson National Accelerator Facility Page 5 TTC 14
Change in Maximum BL Radiation by Cavity 30000 20000 Average Change in BL Radiation = -6944 mR/hr per cavity 10000 Radiation (mR/hr) 0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 -10000 -20000 -30000 Processed Cavity Thomas Jefferson National Accelerator Facility Page 6 TTC 14
Change in Maximum Radial Radiation by Cavity 20000 15000 Average Change in Radial Radiation = -2846 mR/hr per cavity 10000 5000 Radiation (mR/hr 0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 -5000 -10000 -15000 -20000 -25000 Processed Cavity Thomas Jefferson National Accelerator Facility Page 7 TTC 14
Concerns • Higher Than Expected Attrition Rate for GM Tubes • Cold Window Leaks • Eight cavities so far not processed as a result • Several CWWT failures • Result is two cavities not processed and another with no final results • Viewer Replacement work • Forced to skip over zones while BL Vacs are recovered to a usable level • Causes delays • 2L24-7 Quench • Quench caused Performance Degradation – • New Emax ~12 MV/m (Formerly 23 MV/m) • High Field Emission at low gradient • Quench Detection Circuit did not protect (?) • Procedural and software changes aim to prevent a recurrence Thomas Jefferson National Accelerator Facility Page 8 TTC 14
Conclusions • Nine Cryomodules processed since 6/15 • Data for Eight included here • Ten Cavities not processed in this group (14%) • Average increase in Field Emission Onset = 1.1 MV/m • Average Change in Maximum BL Directed radiation = -6.9 R/hr • Average Change in Maximum Radial Directed Radiation = -2.8 R/hr • Schedule says 11 cryomodules finished - 9 actual • Work continues Thomas Jefferson National Accelerator Facility Page 9 TTC 14
Recommend
More recommend
