ATLAS TRT Duke University CERN, Feb Barrel Capacitors With socket and bent pin, forms capacitor assembly Duke supplies capacitors, Hampton assembles
ATLAS TRT Duke University CERN, Feb Baseline: u 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
ATLAS TRT Duke University CERN, Feb HV discharging tests – Duke 2002: u 50 capacitors from each lot charged 2000V then shorted – repeat 3000 times u Measure capacitance, current leakage, arcing u Results: a few failures on surface (dirt?) Average capacitance decreases by a few % u Conclusion: capacitors pass test
ATLAS TRT Duke University CERN, Feb Radiation Hardness Test – Duke/N.C. State 2003 u PULSTAR reactor: 1 MW pool-type; 4% enriched pin-type fuel consisting of uranium dioxide pellets in zircaloy cladding
ATLAS TRT Duke University CERN, Feb Samples for exposure: u For each lot: (four lots) 10 capacitors soldered in parallel on board – will be at HV during test 10 capacitors left in reel packaging
ATLAS TRT Duke University CERN, Feb u All samples, plus assorted glue/tape samples, inside aluminum tube – 19 mm o.d. x 250 mm long – required to fit into reactor
ATLAS TRT Duke University CERN, Feb Radiation: 60 minutes of 30% reactor power u Fast and slow neutrons Total n fluence measured with Co foils – varied from 1.2 to 9 x / cm 2 (top to bottom) ~ 50 years LHC operation u Gammas ~ 2 Mrad 40 capacitors at 2000 V: u Leakage current:.4 μA before / after irradiation.8 μA during
ATLAS TRT Duke University CERN, Feb Results: u Mounted capacitors being kept at HV – no problems so far u Possible decrease in capacitance (< 3%) u Plan to do discharge test on unmounted ones – when they cool off u Will look for “Anatoli Desk Effect” u Plan to test NP0 version u Plan to test full assemblies from Hampton Conclusion: baseline capacitors OK