Rad hardness tests – Sept. 2003 Capacitor assemblies Thermal glue (optional) capacitor barrel sealant Two separate samples: At Georgia Tech – Co60 source, 20 Mrad At N.C. State – reactor, ~50 years LHC

Production Capacitors: Novacap 1808N821K202NX 1808 smaller than previous Johanson 1812 Nominal 820 pF, actual ~875 ~8000 assemblies already produced, uncoated 15 in each radiation sample: 5 with HV experience 10 fresh, coated with Loctite Hysol PC18M Results: No observed effect of radiation ~10 nA @ 2750 V for 10 assemblies + fixture

Looking for radiation induced: Thermal Glue: CHO-THERM 1641, mostly Al2O3 Thermal conductivity 0.9 W/m-K Looking for radiation induced: Change in thermal conductivity Loss of adhesion

Results: Both types of irradiated samples slightly yellow No loss of adhesion to FR4, aluminum, DTMROC, with or without primer Thermal conductivities (preliminary, thick samples not properly cured: Co60: <10% decrease in thermal conductivity reactor: not yet measured

Capacitor barrel sealants Hopefully won’t be needed 3 silicone RTV’s: GE RTV11 – 2 part, viscosity 11000 GE RTV160 – 1 part, viscosity 38000 GE RTV615 – 2 part, viscosity 4000 Samples: filled ULTEM capacitor barrels

Results: No effect from either irradiation RTV11 sticks well, but is removable, with or without primer RTV160 bonds to ULTEM RTV615 very runny, slow curing, removable