1. Multilayer Overview Current application Optimization of Multilayers Model Designs for GRI

2. Grazing Incidence Optics: Past/Present/Future Chandra and XMM Monolitic and replicated Wolter- 1 optics Single layer coated; Ir, Au Hero, High-energy replicated optics InFocus, International Focusing Optics Collaboration, Pt/C HEFT, High Energy Focusing Optics, W/Si NuSTAR, XEUS, Constallation-X

3. High Energy Focusing Telescope (HEFT) 6 m focal length Depth-graded W/Si Multilayers Energy range 20 – 70 keV Effective Area: ~70 cm 2 @ 40 keV Over-constrained optics: 1.2’ HPD Field of view: 17’ @ 20 keV Collaboration: California institute of technology, Lawrence Livermore National Lab., Columbia University, Danish National Space Center

4. The HEFT Optics Parameters: Number: 3Type : Conical Approximation optic Size : 24 cm x 40 cmMaterial : W/Si, multilayers Energy range : 5 – 69 keV

5. Multilayers: HEFT Production Thermally slumped AF 45 borosilicate glass Mirror thickness, 0.3 mm Mirror length = 10 cm Mirror radii: 4 cm < R < 12 cm

6. Multilayers: Design Power law:

7. Multilayers: Optimization, The Figure Of Merit A(E) effective area –A(E) = 2  r  L * [R(E,  )] 2 [R(E,  )] 2 reflectivity matrix, calculated with Nevot-Croce formalism W inc ( ,  ) angular weigthing function – Very CPU intensive W E energy weigthing function = E(keV)/100 + 0.7 P. H. Mao et al, Applied Optics 38,p.4766-4775, 1999a

8. Multilayers: Optimization Constants a and b are uniquely determined by D min and D max For a given max and min graze angle for a group D min and D max are determined by the Bragg equation Multilayer recipes are optimized over: number of bilayers N high Z fraction  power law index c Power law:

9. Model Designs for GRI Double reflectionRadius= 0.1 – 1.0 m Optimized E range = 20 – 500 keV Modified Radius= 0.17 – 0.56 m Double reflection Optimized E range= 40 – 500 keV Single reflectionRadius= 0.09 – 0.44 m Optimized E range= 80 – 200 keV Common Parameters: Substrate thickness = 0.2 mmMirror length = 0.6 m Focal length = 150 mMaterial Combination = W/Si Substrate = SiRadial Obs. Factor = 20%

10. Design 1a: Double reflection R = 0.1 – 1.0 m  = 0.57’ – 5.73’

11. Design 1a Total mass = 2057 kg Number of shells = 1144 Aeff @20 keV200 keV cm2139002023

12. Design 1b: modified double reflection Total mass = 824 kg Number of shells = 582 R = 0.17 – 0.56 m  1.02’ – 3.22’ Aeff @20 keV200 keV cm236531568 Design 1a Design 1b

13. Design 2:Single Reflection R = 0.09 – 0.45 m  = 1.03’ – 5.125’

14. Design 2 Total mass = 190 kg Number of shells = 433 Aeff cm2 @Mass kg 20 keV200 keV Design 219027161160 Optionally: Same design can be used at F = 75 m, as a real focusing System, but with a slight loss in effective area.

15. Conclusions Mass versus Effective area –Real focusing system or single reflection Material combinations –W/Si chosen as a baseline –Pt/C, Pt/SiC, WC/SiC, ( Cu/SiC) Substrate technology –For arcsec performance new developments in substrates are needed –Inherited technology from XEUS, Constallation-X Aeff cm2 @Mass kg 20 keV200 keV Design 1a2057139002023 Design 1b82436531568 Design 219027161160

17. Grp 1 2 S Emin Emax dmin dmax N c Gamma Thick FOM 1 Si W Si 50 200 53.9 495.9 50 0.160 0.287 0.360 9.96 2 Si W Si 50 200 46.9 431.7 63 0.179 0.314 0.393 13.47 3 Si W Si 50 200 40.9 375.8 97 0.190 0.333 0.517 17.90 4 Si W Si 50 200 35.6 327.1 151 0.195 0.344 0.691 22.22 5 Si W Si 50 200 30.9 284.8 187 0.213 0.371 0.755 26.72 6 Si W Si 50 200 26.9 247.9 332 0.207 0.376 1.145 30.22 7 Si W Si 50 200 23.4 215.8 647 0.205 0.370 1.925 33.03 8 Si W Si 50 200 20.4 187.9 1010 0.202 0.372 2.601 32.74