130 likes | 276 Views
Do you believe in Operation Statistics? Presented at the Accelerator Reliability Workshop 2011. Paul Scherrer Institut. Andreas Lüdeke. Paul Scherrer Institute (PSI), Switzerland. PSI: Swiss national research center 1300 employees. Proton facility: 1 MW cw beam Spallation neutron source.
E N D
Do you believe in Operation Statistics?Presented at the Accelerator Reliability Workshop 2011 Paul Scherrer Institut Andreas Lüdeke
Paul Scherrer Institute (PSI), Switzerland PSI: Swiss national research center 1300 employees • Proton facility: 1MW cw beam • Spallation neutron source • Proscan SC cyclotron • Cancer therapy • Swiss Light Source (SLS) • e- storage ring • 400mA, 2.4 GeV PSI West: Large Research Facilities Andreas Lüdeke, Paul Scherrer Institute at the ARW11 in Cape town, 11-Apr-2011 Slide 1
Swiss Light Source Operation • Swiss Light Source is • In operation since 2001 • A user facility with 19 beam-lines in operation • Providing ~ 5000 hours beam to users per year • Users need to apply for beam time • Just 30% of the proposals are accepted • Accepted users need to wait about 6 month for beam time • One important metric to judge machine quality Andreas Lüdeke, Paul Scherrer Institute at the ARW11 in Cape town, 11-Apr-2011 Slide 2
3rd Generation Synchrotron Light Sources: Availability Availability [%] Year Andreas Lüdeke, Paul Scherrer Institute at the ARW11 in Cape town, 11-Apr-2011 Slide 3
Availability: "Concours des Alpes" Availability [%] Year Andreas Lüdeke, Paul Scherrer Institute at the ARW11 in Cape town, 11-Apr-2011 Slide 4
Availability: "Concours des Alpes" Availability [%] Year Andreas Lüdeke, Paul Scherrer Institute at the ARW11 in Cape town, 11-Apr-2011 Slide 5
Metrics of the Swiss Light Source (SLS) Availability definition: “Delivered_Beam_Time” = “Beam_for_Users” during “User_Time” “User_Time" = “Scheduled_User_Time" + "User_Reserve_Time” Example for 2005: • Uncompensated Availability Andreas Lüdeke, Paul Scherrer Institute at the ARW11 in Cape town, 11-Apr-2011 Slide 6
Elettra Metrics for Availability • Thunderstorms are excluded from failure statistics at Elettra • Example from 2005: • Availability including outages from thunderstorms: Andreas Lüdeke, Paul Scherrer Institute at the ARW11 in Cape town, 11-Apr-2011 Slide 7
Availability: "Concours des Alpes” corrected Bare Availability [%] Year Andreas Lüdeke, Paul Scherrer Institute at the ARW11 in Cape town, 11-Apr-2011 Slide 8
Special Events: ESRF 2005 and the Crotch Absorber • In March 2005 • A water-to-vacuum leak • Five days of user operation lost • 120 hours downtime • ESRF statistics 2005 • Availability 97.6%, • Total User Operation 5496 hours • 131 hours downtime • How can that be? • All users of 5 days re-scheduled • Not counted as downtime Andreas Lüdeke, Paul Scherrer Institute at the ARW11 in Cape town, 11-Apr-2011 Slide 9
What can we learn from this? • Availability statistics not proportional to system reliability • But large effort spend to compile downtime statistics • Accurate failure data exists, but kept internal. Why? • If that would be public, what could it be used for? Andreas Lüdeke, Paul Scherrer Institute at the ARW11 in Cape town, 11-Apr-2011 Slide 10
RF arcing at the Swiss Light Source • Background • SLS has 60 to 100 beam outages per year • About 20 outages were caused by RF arcs • Inquiry • Asking around at the EPAC’08: “What is your experience with arc detectors?” • Answer: arc detectors are often unreliable! • Action • We are replacing detectors with arc-coincidence detectors • Result • No arc interlock from any upgraded detector! • Single diodes still show arcs, but do not cause interlocks • Conclusion • We had in 10 years 200 unnecessary beam losses! Andreas Lüdeke, Paul Scherrer Institute at the ARW11 in Cape town, 11-Apr-2011 Slide 11
What can we do? • What we do now • We do your own mistakes • Sometimes we share selected insights during workshops • What we should do • Learn from the failures of others • Create a database of all outages of many facilities! • How to do that? • Define a simple document format • Provide a web-platform to publish downtime event data • I’ll start, will you join? • Participate in the Friday morning discussion! • . • . Andreas Lüdeke, Paul Scherrer Institute at the ARW11 in Cape town, 11-Apr-2011 Slide 12