1. 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

2. 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
~ V for 10 assemblies + fixture

3. 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

4. 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

5. 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

6. 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