Department of Physics, University of Michigan SNAP NIR Detector Packaging Development: First results from FEA of SiC / EA9361 / Moly Package Bruce C. Bigelow Department of Physics, University of Michigan 30 June 2005

FEA of SiC Package with insert Motivations: Investigate effects on NIR package due to epoxy bonded moly insert Sub-model of insert and surrounding SiC Material CTE values included as a function of temperature (120-295K) Temperature excursion from 295 to 120K Still need epoxy (Hysol 9361) E(T) data Moly insert (TZM later) Nominal bond line of 200 microns First results are for insert offset by 50 microns in ideally located hole Package depth is 8mm Insert height is 6mm Air gap above insert 0.5mm 30 June 2005 B. C. Bigelow -- UM Physics

UM SNAP NIR Package Design 30 June 2005 B. C. Bigelow -- UM Physics

Full geometry FEA model (1/2 shown) Note epoxy bond variation due to insert decentering 30 June 2005 B. C. Bigelow -- UM Physics

Constraints on base of insert 30 June 2005 B. C. Bigelow -- UM Physics

Equiv. Stresses in materials (Pa) 30 June 2005 B. C. Bigelow -- UM Physics

Equiv. Stresses epoxy (Pa) 30 June 2005 B. C. Bigelow -- UM Physics

Equiv. Stresses in SiC (Pa) 30 June 2005 B. C. Bigelow -- UM Physics

Opt. axis motion in SiC (m) 30 June 2005 B. C. Bigelow -- UM Physics

Deflection in top surf. of pkg (m) 30 June 2005 B. C. Bigelow -- UM Physics

NIR Package with insert FEA Conclusions: First results only – more coming as a function of insert offset, mat props, etc Stresses in all materials are very low Deflections at top of package are negligible 30 June 2005 B. C. Bigelow -- UM Physics