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A. Denker Reliability gemäß LEO: Ausfallsicherheit Betriebssicherheit Funktionsfähigkeit Verlässlichkeit Zuverlässigkeit . Bericht vom Accelerator Reliability Workshop ARW 2011. Statistik: Übersicht. 1. 2002 ESRF 2. 2009 Triumf 3. 2011 Kapstadt 41 Beiträge von Beschleunigern
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A. Denker Reliability gemäß LEO: Ausfallsicherheit Betriebssicherheit Funktionsfähigkeit Verlässlichkeit Zuverlässigkeit Bericht vomAccelerator Reliability WorkshopARW 2011
Statistik: Übersicht • 1. 2002 ESRF2. 2009 Triumf3. 2011 Kapstadt • 41 Beiträge von Beschleunigern • 78 Teilnehmer, ohne “Locals”: 1/3 Amerika, 1/5 Asien, knapp ½ Europa • 3 Beiträge aus anderen Einrichtungen • Kernkraftwerk Koeberg, • SALT (South African Large Telescope): jwd, Temp.gradienten • South African Square Kilometer Array Project: jwd, möglichst ferngesteuert, da bereits ein Handy stört • Zwei Diskussionsrunden • Magnete • Webseite/Forum
Statistik: wer war da • Lichtquellen:SLAC, BNL, Diamond, ESRF, PSI, Australian synchroton, Spring8, SSRF • Spallationsquellen:PSI, SNS • Zyklotrons:allg.: NSCL, iThemba, Uppsala, RIKEN, IBAmed.: MGH, Orsay, HZB, • Sonstige:GSI, HIMAC, INFN, DaLinac, Siemens, CERN, Fermilab
Automatisierung: Australien • Lichtquellen:SLAC, BNL, Diamond, ESRF, PSI, Australian synchroton, Spring8, SSRF • Spallationsquellen:PSI, SNS • Zyklotrons:allg.: NSCL, iThemba, Uppsala, RIKEN, IBAmed.: MGH, Orsay, HZB, • Sonstige:GSI, HIMAC, INFN, DaLinac, Siemens, CERN, Fermilab
RF verbessert: RIKEN Ringzyklotron Erreichtdurch • Vakuumverbessert • CW – konditionieren…
RF verbessert: DALINAC Temp.sensor auf RF Regelkarte
Diagnose: DiamondRemotely Controlled, Mobile, Thermal Imaging Platform
Reliability unter besonderen Umständen uptime: 94%
Zusammenfassung • Erfahrungsberichte aus der Praxis – nicht geschönt • große Unterschiede zwischen den Beschleunigeranwendungen: • die Probleme sind jedoch bei allen ähnlich • intensiver Austausch, sowohl in Podiumsdiskussionen • Lüdeke - zentrale Datenbank für Reliability, andreas.luedeke@psi.ch • Spencer - http://slac.stanford.edu/pubs/slactns/tn04/slac-tn-09-001.pdf als auch mit den Teilnehmern • viele Ideen für zu Hause mitgebracht
History • 1977: start of cyclotron operation for nuclear physics (VICKSI) • 1995 – 2006: Ionenstrahllabor ISL – laboratory for ion beam applications • internal and external (~ 70%) users • ion energy: eV < Eion< 800 MeV • research areas: • materials modification and ion-solid-interaction • materials analysis • medical applications • since 2007: accelerator operation for therapy purposes only
Accelerator Layout 5.5 MV Van-de-Graaff RFQ 2 x 14.5 GHz ECR sources on 150 kV platforms 16 dedicated target stations k = 132
Accelerator Performance cyclotron in operation since 1977 averaged downtime before 1995: 10 % start of therapy start of RFQ operation for users
Reduction of Downtime step by step process addressing all subsystems:sources, injectors, beam lines, cyclotron, control system • preventive maintenance • increased redundancy • modernisation • improved diagnosis • reduction of elements
Preventive Maintenance • regular belt change of Van-de-Graaff • service of rotating parts • cyclic change of spare power supplies used on HV terminal • drying of SF6 gas • cleaning of isolators • service on vacuum pumps: oil, bearings • replacement of water tubes
Modernisation • new computers for control system • replacement of old dipole power supplies • exchange of shunt against transducer regulation in quadrupole power supplies (gain in stability: factor 10) • discrete rectifiers replaced by complete 3-phase modules • replacement of main coil power supply of cyclotronside effect: less energy consumption
Redundancy / Reduction of elements • smaller variety of pumps, vacuum gauges, power supplies…. • whenever possible: spare parts for quick exchange • low intensity proton beams: no pre-bunching • no water cooling of deflector plates in beam line dipoles
Improved Diagnostics • display of accelerator status
Improved Diagnostics • display of accelerator status • 24 h charts start of main magnet overshoot procedure
Improved Diagnostics • display of accelerator status • 24 h charts • beam stability programme
ISL Protons for Therapy (PT) • 11/04: decision to close ISL at the end of 2006 • Post-Docs and technical staff on temporary positions left • people were transferred to other departments • stop of investments • 9/06: start of planning operation solely for PT • reduced man-power(less beam-time) • reduction of beam lines, cables… • this step: almost completed • nevertheless:maintain reliability
Accelerator Performance small number of beam time hours: major events have huge impact on statistics ~ 4500 hours/year ~ 1750 hours/year
ISL PT: Operation Comparison • H, 68 MeV • cyclotron fixed frequency • one NMR-probe/dipole • 2 target stations, identical focusing • 1/4 of existing beam line system • 12 therapy weeks/year • 2 shift operation (6:00 -22:00) • Thursday: start up and tuning • Friday: quality control of accelerator • weekend: standby* • Monday-Friday: Therapy • changing ion species and energies • ~ 15 target stations varying requirements on focusing • 34 weeks/year • 3 shifts a day (24/24) • exceptions on weekends: - experiments- infants, requiring more than 4 sessions
PT: Reliability • availability 95 % in 20072/3 of downtime due to one major event: electrostatic injection • preventive maintenance • replacement of Ta shields by Ti (good experience in ECR source) • after one week: failure • fault of new ceramics ? • Ti shields (now Ta again) • delay of 2 days • uptime 2008: 98 %worst case: failure in electricity supply at 6:00 am • delay of 2 hours
Accelerator Operation: Reliability • uptime 2009: 95 %1/3 of downtime again due to one major event: water leak in RF • interruption of therapy week for the first time since 1998 (110 therapy weeks) • availability 2010: 95 %frequent drops in RFerror difficult to find: isolator problems on tube socket of anode power supply
Lessons Learned • turbo pumps on 60 % of rotational speed (standby mode) increases service intervals about factor 5 • analysis of residual gas for water • logging of electricity for failure analysis cryo pumps on cryo pumps off