FNAL Linac Downtime Overview Proton Source Workshop Fernanda G. Garcia Accelerator Division Proton Source Department December 7-8, 2010 X 3798

Few points you need to know...  Data presented in this talk was obtained using the Operations Department Downtime Logger (1977 is the earliest year logged)  Data was analyzed exporting data into excel file and filtering entries  Legend Linac Downtime Proton Source Workshop Fernanda G. Garcia December 7-8, 2010 TLDTotal Linac Downtime PDPre-Acc Downtime CDComplex Downtime Contribution

Linac Downtime History Linac Downtime Statistics Proton Source Workshop Fernanda G. Garcia December 7-8, 2010 Linac Availability : 89% TLDTotal Linac Downtime PDPre-Acc Downtime CDComplex Downtime Contribution TLD: ~ 3,470 hrs CD: 11.0% MiniBooNE April’02 Pbar stacking Aug’04 NuMI May’05 NuMI slipstacking Jan’08

Linac Downtime History Linac Downtime Statistics Proton Source Workshop Fernanda G. Garcia December 7-8, 2010 TLD: ~ 6,660 hrs CD: 10.5 % TLDTotal Linac Downtime PDPre-Acc Downtime CDComplex Downtime Contribution Linac Availability : 89.5 %

Linac Downtime History Comparing the past decade with the previous 2 decades Linac Downtime Statistics Proton Source Workshop Fernanda G. Garcia December 7-8, 2010 Data shows that  52% TLD happened in the past decade  Linac RF systems contributed 0.5% more to the CD in the past decade than it did in the previous 23 years  HE ~ 42% contribution  1 single failed contributed ~11% of HE downtime (KRF1 replacement)  LE ~ 58% contribution TLDTotal Linac Downtime PDPre-Acc Downtime CDComplex Downtime Contribution

Linac RF System Linac Downtime Statistics Proton Source Workshop Fernanda G. Garcia December 7-8, 2010 ~ 60% 200 MHz system TLD ~ 40% 805 MHz system TLD TLDTotal Linac Downtime PDPre-Acc Downtime CDComplex Downtime Contribution LRF1 LRF2 LRF3 LRF4 LRF5

Linac RF System Linac Downtime Statistics Proton Source Workshop Fernanda G. Garcia December 7-8, 2010 Modulator contribution LD ~ 57% Driver contribution LD ~ 35% Despite the fact the majority of the modulator downtime is < 30 min, these frequent interruptions Avg: ~4.5 hrs Avg: ~ 10 min Avg: ~ 45 min to running a smooth program, occupy manpower resources with local response, frequent tuning and constant attention to Linac beam quality. They are also a repeated stress on the system hardware.

Linac Downtime Concerns Linac Downtime Statistics Proton Source Workshop Fernanda G. Garcia December 7-8, 2010  200 MHz QPS  20 uF 1kV capacitors with 1.6 lb PCB oil  12 capacitors/supply ~ 120 supplies  Major downtime risk due to environmental impact and extensive of cleaning on other components which will get affected by this failure.  Currently replacing the PCB with non-PCB caps  Ignitron in the Modulator Capacitor bank  Hg -> environmental problem if it explodes  Drift Tube Failure  Historical fact: 5 quadrupole failures over Linac Operations  Tank 2:  3 failures, all caused by ground fault in the magnet.  Tank 5  2 failures initiated by water leak in the stem box  Typically is possible to adjust other magnets (isolation transformer)  Multiple failures, problem becomes more challenging and perhaps Impossible to sustain operations until magnets are replaced.

Pre-Accelerator Downtime System Linac Downtime Statistics Proton Source Workshop Fernanda G. Garcia December 7-8, 2010 During the past 10 years 11.5% TLD 1.2% CD H - system (6.7% TLD, 0.7% CD) I - system (3.3% TLD, 0.4% CD) TLDTotal Linac Downtime PDPre-Acc Downtime CDComplex Downtime Contribution Largest Single Downtime  2006  26 hrs: Short on the H - extractor. I - turn on/tune up.  2010  52 hrs: H - source repair. I - column under repair and H - source died  Operation Risks  Haefely failure  lack of experience  Overall lack of experience past 2 years Dept. lost 120 years of expertise/experience  Loss of redundancy

Pre-Accelerator Downtime System Linac Downtime Statistics Proton Source Workshop Fernanda G. Garcia December 7-8, 2010 During the past 33 years ~ 15% TLD ~ 1.5% CD TLDTotal Linac Downtime PDPre-Acc Downtime CDComplex Downtime Contribution Largest Single Downtime  1983  15 hrs: I - source replacement  1993  22 hrs: H - generator died Reliability is a concern for instance in 1988 there was no single failure. The downtime was a combination of small power supply trips, regulation issues which caused interruption to a smooth running. Downtime (hrs)

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