Definition of Baseline Lens Material The Mitsubishi-000 ultra pure UVT-PMMA is the current baseline lens material. The dispersion of the index of refraction is lower compared to other samples of UVT-PMMA. The transmittance in the wavelength region nm is higher compared to standard UVT-PMMA.

Definition of Baseline Lens Material

The requirements of the optical sub-system have identified two design goals for the lens material: The absolute value of the dispersion of the index of refraction must satisfy, Δn  , in the wavelength interval nm. The transmission must be equal to or greater than the values: 97% at 400 nm, 95% at 360 nm, and 92% at 330 nm for a thickness of 10 mm.

Definition of Baseline Lens Material PMMA Measurement Optical ProperitiesValueUnitsProcedure/Conditions dN/dT - change in index of refraction with temperature1.05E-04/ºC dN/dl - change in index of refraction with wavelengthn d =1.491 UV Light Transmission (bulk material)92%400 nm, 3 mm plate Mechanical Properties Coefficient of Thermal Expansion8.00E-05/ o C Density g/cm 3 Tensile Strength at the Yield Point kg/cm 2 Ultimate tensile strength kg/cm 2 Thermal Conductivity4.96E-04cal/cm/sec/ o C Young's Modulus of Elasticity3.16E+04kg/cm 2 ASTM D 638 (ISO 527-1) Glass Transistion Temperature Range oCoC Water Absorbency0.3%Measured at 60 o C

Definition of Baseline Lens Material Allow the manufacturer the freedom to achieve these two goals by varying other physical parameters such as the index of refraction, and the density. One an example of this approach is the partial fluorination of UVT-PMMA. Outer cladding of double clad optical fiber Kuraray Plastics, Inc. (n = 1.42) NRL Chemistry Division ( n = 1.437) Note: Fully fluorinated co-polymer CYTOP (n = 1.34) has a density of 2.0 g/cm 3.

Definition of Baseline Lens Material U.S. Plastic Manufacturers: Reynolds Polymer Technology, Inc. Gained experience fabricating the acrylic containment vessel as part of the Sudbury Neutrino Observatory (SNO) experiment. Can manufacture 3 m X 3 m lens blanks. Spartech/Polycast (2 m X 2 m lens blanks) CYRO Industries (Maximum thickness 1 inch) Japanese Plastic Manufacturers: CI Industry Co. (Non-additive UVT-resin) Mitsubishi (000) Asahi Glass (Fluoropolymers, CYTOP)