1. Pt as a release layer for IXO thermally formed glass optics: preliminary results S. Romaine, R. Bruni, P. Gorenstein, S. Park, P.Reid Harvard-Smithsonian Center for Astrophysics Platinum and boron nitride are two of the materials being considered as release layers for thermally slumping glass substrates for IXO. SAO is investigating the use of platinum as a release layer for IXO glass substrates. Recent experimental results using dc magnetron sputtered platinum coatings will be presented.

2. Process Clean substrates dc magnetron deposit ~ 450 Å Pt on glass Characterize (XRR, AFM, WYKO) Thermal anneal – flat mandrel (fused silica) Characterize (XRR, AFM, WYKO) Test Substrates: D263 schott glass 400 µm thick 5cm diameter

3. SAO Coating Facility R&D chamber – small substrates Chamber I.D. = 23.5 in. ; height = 13 in Turbo pump, base pressure = 1x10 -7 Torr RandD Chamber Cross Section Magnetron1Magnetron2 Substrate1Substrate2 Variable Height Rotary Platen

4. 54 hour slumping cycle 17.5 cm diameter fused silica flat mandrel 5 cm diameter D263 coated glass Max temp = 580

5. Pre vs. Post slumped 8 keV XRR data Graze angle (deg) Red = pre-slump data; Green = post-slump data

6. 8 keV XRR data - taken at SAO XRR facility Data Fit using D. Windt IMD software 8 keV XRR data+ models 525 Å thick Pt film on D263 400 µr thick glass substrate Model: µr(Pt) = 5.5 Å µr(sub) =4.0 Å Model: µr(Pt) = 14.0 Å µr(sub) = 7.0 Å Pre-slumpPost-slump Graze angle (deg) Reflectivity Red = data Green = model Red = data Green = model

7. 3 µm AFM scans: uncoated, pre-slump, post-slump Uncoated D263, µr =2.1 Pt coated, pre-slump, µr =4.0 Pt coated, post-slump, µr =9.1

8. AFM 1 µm scans: Uncoated, Pre-slump, Post-slump Uncoated D263 Pt coated, pre-slump Pt coated, post-slump

9. XRR (Å) **WYKO (Å) AFM (Å) PrePostPrepostPre-slumpedPost-slumped 1µ m sca n 3µm scan 10µm scan 1µm scan 3µm scan 10µm scan 1a5.5141.92.1--3.23.57710 2a5.015.51.72.03.43.23.17.51013 3a5.014.02.31.8--4.43.17911 6b4.5131.31.6--2.82.67.5714 *5b4.5n/a1.61.8*4.1 444.5 D263 -bare 3.01.71.6222.6n/a *Sample 5b was a control sample. It was coated with Pt and characterized, but was not slumped ** all WYKO data taken at MSFC (B.Ramsey, T. Kester) Microroughness data for Pt films pre and post slumping

10. Summary These are first – preliminary - results of this study Obvious advantages if release layer is also X-ray reflector – M.Ghigo/G. Pareschi found smaller effect (of roughness) with thicker substrates Work continues …….

11. END

12. XRR Z (Å) ρ Pt (%) ρ sub (%) σ Pt (Å) σ sub (Å) 1a pre 526991005.54.0 post 5229710014.07.0 2a pre 448991005.0 post 4419110014.77.0 3a pre 466991005.0 post 4659710014.07.0 6b pre 483991004.55.0 post 48597100137.0 5b 378991004.55.0

13. Pt on 400 µm D263 3 µm scan 10 µm scan(Preslumped)