Failure Mode: CPA

Surface Finish ProblemQA (Design)QC (Production) CPA edge tube surface scratches Shipping/handling procedures Visual inspection HV test HV cup surface scratches Shipping/handling procedures Visual inspection HV test Discharge along CPA hanger Design and prototype test HV test 2

Electrical Interconnect Thermal Cycle / After a Spark ProblemQA (Design)QC (Production) Connection between HV cup and HV bus Design and prototype testResistance check thermal cycle HV bus connection between modules Design and prototype testResistance check thermal cycle HV bus connection to the CPA corners Design and prototype testResistance check thermal cycle Connection between tube ends and the resistive tube Design and prototype testResistance check thermal cycle Resistor connection between main sheets and field shaping strips Design and prototype testResistance check thermal cycle Interconnect between neighboring resistive sheets Design and prototype testResistance check thermal cycle 3

Mechanical Problems ProblemQA (Design)QC (Production) Bad rounding radii on mating parts Design and prototype testVisual inspection Fasteners come loose after thermal cycling Design and prototype testThermal cycle Warping of structure after thermal cycling Design and prototype testThermal cycle Delamination of resistive film after thermal cycling Design and prototype testThermal cycle Uneven gap between modules in LAr Design and prototype test Specification 4