MTE: Statistics of kickers faults Etienne Carlier, Luis Feliciano, Laurent Ducimetière, Brennan Goddard, Luc Sermeus 1 19 October 2015 MTE internal review

2 Estimation of fast failure rates for MTE kickers (faulty shots) and comparison with other system (KFA71-79) Slow failure statistics Impact of additional user cycles Ageing effect & concerns Outline 19 October 2015 MTE internal review

3 19 October 2015 MTE internal review

4 SystemNumber of pulses (millions) Faulty shots (spontaneous) Fault rate per million pulses KFA13-21, Gen # KFA13-21, Gen # KFA13-21, Gen # KFA 4, Gen #1 with east & TOF Main switch Dump switch KFA 4, Gen #1 MTE only (25 Sept) Main switch Dump switch For comparison : KFA71-79 Total Ratio Max/min 143 KFA71-79 min KFA71-79 max October 2015 MTE internal review Thyratron spontaneous triggering : beam losses, unclosed bump … Estimation of fast failure rate Not detected before extraction

5 KFA13-21 generators HT50 Lemo connectors: 4 ( switch to spare =1/2 days off ) 1 man·day to repair KFA4 generators Magnet spark: 100, operation resume normally Missing pulse; other possible cause Timing error, or open contact in the timing chain Thyratron trigger unit, or open contact in the triggering chain Estimation of fast failure rate Not detected before extraction 19 October 2015 MTE internal review

6 KFA13-21 generators Capacitor unit: 2 ( few hours off ) Charge Control unit: 9 ( few hours off, now fixed ) HV Capacitor in PFN: 1 ( switch to spare =1/2 days off ) 4 man·week to repair KFA4 generators Thyratron: 2 ( 1/2 days off ) Thyratron bias unit: 2 ( 1/2 days off ) Charge Control unit: 1 ( few hours off ) Accidental water in oil system: 1 ( 2 weeks off ) 4 man·week to repair Slow failure statistics Detected before extraction 19 October 2015 MTE internal review

7 Fast failure rate largely dependant of individual thyratron Additional user cycles will increase fast failure: Proportionally to number of shots Additional fault due to varying the operational voltage Impact of additional user cycles 19 October 2015 MTE internal review

8 Limited components life time, depending of applied voltage Thyratron, regularly changed (20 kCHF + 2 man.days) require increasing adjustment effort with age (1 thyratron = 15% of PS kicker budget); Capacitors Contacts (Transmission cables) (Step-up charge transformer) Concerns KFA 13-21: Adapted from design for short pulses KFA 13-21: no spare KFA 4 : one spare magnet module, no tank Ageing effect & concerns 19 October 2015 MTE internal review

Conclusion Large range of statistics for fast failure rate Additional users will increase fault rate more than proportionally Ageing effect can impact availability No spare magnet / tank  Detailed implications to be defined (consolidation strategy, spares, controls, exploitation budget, manpower);  Justify maintaining the CT operational as fall back for the fixed target October 2015 MTE internal review