TTF1/TTF2/XFEL/LC stability/reliability Stability: FEL requests beyond specs. What was measured? What needs to be measured What needs to be compared to simulation ….. Improving is a learning curve: first TTF1

TESLA Test Facility - Operation week 3 / 2002 FEL User Operation week 7 / 2002 Accelerator Studies 100% 80% 60% 40% 20% Beam uptime and operational uptime (users or acc.studies) The TTF Linac was operated 7 days per week, 24 hours. Approx. 50% of the time was allocated to FEL operation including a large percentage of user time. The FEL requires very stable beam conditions. In its different set-ups, approx. 13,000 hours beamtime were achieved since Based on the TTF experience several FELs using superconducting accelerator technology are proposed week Courtesy M. Minty

TTF OPERATIONS STATISTICS To direct accelerator improvements aimed at increased reliability, the operational statistics at the TTF are now logged on a per-shift basis. Initially these data were compiled to reveal outstanding hardware limitations. As reliability at the TTF continues to improve, correspondingly finer classifications have evolved. In the future, perhaps an automated analysis could be implemented. At present, the TTF operators are requested “to the best of his/hers ability” to classify the time spent during each shift into 1 of 5 categories: CATEGORIES: USERS - beam delivery for experimental programs using the intense SASE radiation (i.e. ABLO, Cluster, RAFEL) STUDIES - all studies pertaining to accelerator development aimed towards quantification and improvement of beam properties (i.e. CSR, BTM, BBA, etc) and /or demonstrating TESLA-like beam conditions (i.e. high charge, high gradient, long pulses, etc.) TUNING - all time spent with beam providing the required condition for the users or accelerator development DOWN - downtime caused by hardware failure or anything else which prohibits operations OFF - time with no beam arising from transitioning between experiments (e.g. ABLO/CLUSTER ), accelerator improvements, and holidays Courtesy M. Minty

TTF operations statistics Focus: rafel,cluster,sfpd How much of the 53% is really available for users (missing pulses)? What caused the downtime? What is the reason for tuning Different machine-setting Drift of the machine More accurate specification of machine status Courtesy M. Minty

DOWNTIME SUMMARY SINCE SHUTDOWN ( ): How do problems occur (once or regular) Courtesy Michiko Minty laser gun Gun vac CC Kly3 Cryo Vacuum

Machine Stability/performance What parameters need to be measured ( slice? ) SASE, Charge, offset/angle (orbit), energy, phases, losses…. What parameters need to be correlated How often do we need to store data (DAQ) Slow drifts (tuning), Fast fluctuations (instability) How flexible do we need to store data ….. ?

Modes of operation Gun/Injector/Analysis/Linac mode (BIS) Down/off/user/study/tuning mode (DOOCS panel) Information availability With mode definition All relevant information is available All important data are saved and easily accessible for data analysis (tools: history plots, correlation) Statistics is kept for logbook Leaving a mode stores changes of relevant parameters and plots in the logbook

Information gathering How to make sure that operators are in the correct mode Wrong mode=wrong information saved Unknown cause of failure/instability Get info from the DAQ (Much work: is it available?) Flexible DOOCS panels/tools for different modes