Helium Processing Progress M. Drury SRF Schedule vs. Actual - - PowerPoint PPT Presentation

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Jan 05, 2024 484 likes •583 views

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

SLIDE 1

Helium Processing Progress

M. Drury

SRF

SLIDE 2

Thomas Jefferson National Accelerator Facility

Page 2 TTC 14

Schedule vs. Actual Schedule Actual

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

SLIDE 3

Thomas Jefferson National Accelerator Facility

Page 3 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 2L20 1.6 C20 /C50 Average Gain 3.9 2L21 1L22 7.14 2L22 2L23 2L24 2L25 11.3 2L26 6.2 C100 Average Gain

8.2

Overall Average Gain

5.2

SLIDE 4

Thomas Jefferson National Accelerator Facility

Page 4 TTC 14

2 4 6 8 10 12

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 Frequency Change in FE Onset (MV/m)

Distribution of FE Onset Deltas

Average Change = 1.1 MV/m

Includes 1L02 and 1L22 – Processed in Jan 2015

SLIDE 5

Thomas Jefferson National Accelerator Facility

Page 5 TTC 14

GM Tube Locations

Top Center WG2 WG3 WG6 WG4/5 WG7 WG8 WG1 BL Sup BL Ret BL Sup BL Ret Top Center WG20 WG30 WG40 WG50

WG tubes and Top Center = Radial BL Supply and Return = BL

SLIDE 6

Thomas Jefferson National Accelerator Facility

Page 6 TTC 14

30000
20000
10000

10000 20000 30000

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

Radiation (mR/hr) Processed Cavity

Change in Maximum BL Radiation by Cavity

Average Change in BL Radiation = -6944 mR/hr per cavity

SLIDE 7

Thomas Jefferson National Accelerator Facility

Page 7 TTC 14

25000
20000
15000
10000
5000

5000 10000 15000 20000 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

Radiation (mR/hr Processed Cavity

Change in Maximum Radial Radiation by Cavity

Average Change in Radial Radiation = -2846 mR/hr per cavity

SLIDE 8

Thomas Jefferson National Accelerator Facility

Page 8 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

SLIDE 9

Thomas Jefferson National Accelerator Facility

Page 9 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