Barrel Capacitors - PowerPoint PPT Presentation

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Barrel Capacitors

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  1. Barrel Capacitors • With socket and bent pin, forms capacitor assembly • Duke supplies capacitors, Hampton assembles

  2. Baseline: • Johanson 202S43W102KV4E: • 202: 2000V • S43: size 1812 = 4.45 x 3.18 x 2.16 mm • W: X7R dielectric – but NP0 now available • 102: 1,000 pF • K: tolerance ±10% • V: nickel barrier termination • 4: no marking • E: 7 inch embossed reel (1000 pieces) • Four reels from different lots purchased for tests

  3. HV discharging tests – Duke 2002: • 50 capacitors from each lot charged up @ 2000V then shorted – repeat 3000 times • Measure capacitance, current leakage, arcing • Results: • a few failures on surface (dirt?) • Average capacitance decreases by a few % • Conclusion: capacitors pass test

  4. Radiation Hardness Test – Duke/N.C. State 2003 • PULSTAR reactor: • 1 MW pool-type; 4% enriched pin-type fuel consisting of uranium dioxide pellets in zircaloy cladding

  5. Samples for exposure: • For each lot: (four lots) • 10 capacitors soldered in parallel on board – will be at HV during test • 10 capacitors left in reel packaging

  6. All samples, plus assorted glue/tape samples, inside aluminum tube – 19 mm o.d. x 250 mm long – required to fit into reactor

  7. Radiation: 60 minutes of 30% reactor power • Fast and slow neutrons • Total n fluence measured with Co foils – varied from 1.2 to 9 x 1014 / cm2 (top to bottom) • ~ 50 years LHC operation • Gammas • ~ 2 Mrad • 40 capacitors at 2000 V: • Leakage current: • .4 μA before / after irradiation • .8 μA during

  8. Results: • Mounted capacitors being kept at HV – no problems so far • Possible decrease in capacitance (< 3%) • Plan to do discharge test on unmounted ones – when they cool off • Will look for “Anatoli Desk Effect” • Plan to test NP0 version • Plan to test full assemblies from Hampton • Conclusion: baseline capacitors OK