multilayer overview current application optimization of multilayers model designs for gri
TRANSCRIPT
Multilayer Overview
• Current application• Optimization of
Multilayers• Model Designs for GRI
Grazing Incidence Optics: Past/Present/FutureChandra 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
High Energy Focusing Telescope (HEFT)
6 m focal length
Depth-graded W/Si Multilayers
Energy range 20 – 70 keV
Effective Area: ~70 cm2 @ 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
The HEFT Optics
Parameters: Number: 3 Type : Conical Approximation optic
Size : 24 cm x 40 cm Material : W/Si, multilayers
Energy range : 5 – 69 keV
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
a) Lay down andmachine graphite spacers
c) Lay down andmachine graphite spacers
b) Lay down glass
d) Lay down glass
Q u ar tz M an d re l G lass M icro sh ee t
(1 )
(3 ) (4 )
(2 )
Multilayers: Design
ciib
aD
)( Power law:
Multilayers: Optimization, The Figure Of Merit
• A(E) effective area– A(E) = 2rL * [R(E,)]2
• [R(E,)]2 reflectivity matrix, calculated with Nevot-Croce formalism
• Winc(,) angular weigthing function – Very CPU intensive
• WE energy weigthing function = E(keV)/100 + 0.7
E
N
i E
E
E
WEE
EWEAdE
)(
)()( FOM
minmax
1
max
min
P. H. Mao et al, Applied Optics 38,p.4766-4775, 1999a
Multilayers: Optimization
• Constants a and b are uniquely determined by Dmin and Dmax
• For a given max and min graze angle for a group Dmin and Dmax are determined by the Bragg equation
• Multilayer recipes are optimized over:
number of bilayers N
high Z fraction power law index c
sin2Ehc
D
ciib
aD
)( Power law:
Model Designs for GRI
• Double reflection Radius = 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 reflection Radius = 0.09 – 0.44 m
Optimized E range = 80 – 200 keV
Common Parameters:
Substrate thickness = 0.2 mm Mirror length = 0.6 m
Focal length = 150 m Material Combination = W/Si
Substrate = Si Radial Obs. Factor = 20%
Design 1a: Double reflection
Group Emin Emax dmin dmax N c Gamma Thick1 120 500 66,301 309,961 50 0,385 0,300 0,5122 120 500 59,091 276,253 27 0,185 0,500 0,2113 120 500 52,664 246,21 33 0,216 0,494 0,2344 120 500 46,937 219,435 51 0,204 0,472 0,3115 120 500 41,833 195,572 62 0,219 0,509 0,3406 80 500 37,284 261,455 106 0,212 0,404 0,5177 80 500 33,229 233,022 150 0,222 0,436 0,6548 80 500 29,615 207,681 206 0,231 0,428 0,8049 80 500 26,395 185,096 363 0,225 0,399 1,24510 80 300 39,207 164,964 87 0,214 0,468 0,43911 40 300 34,944 294,054 135 0,211 0,379 0,61712 40 300 31,143 262,076 187 0,218 0,394 0,76113 40 300 27,757 233,576 291 0,226 0,392 1,05614 40 300 24,738 208,175 453 0,227 0,361 1,46115 40 180 36,746 185,536 100 0,203 0,450 0,47016 20 180 32,75 330,718 195 0,196 0,327 0,81817 20 180 29,189 294,753 303 0,182 0,351 1,10318 20 180 26,014 262,699 378 0,198 0,356 1,24419 20 180 23,185 234,13 472 0,204 0,386 1,39120 20 180 20,664 208,669 737 0,209 0,385 1,938
R = 0.1 – 1.0 m = 0.57’ – 5.73’
Design 1aMass
0
50
100
150
200
250
300
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Group
Kg Mass
Total mass = 2057 kg
Number of shells = 1144
Aeff @ 200 keV
0
0,5
1
1,5
2
2,5
3
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Aeff/Mass/Ageom * 100cm2
Aeff/Ageom
Aeff/Mass
Aeff @ 20 keV 200 keV
cm2 13900 2023
Design 1b: modified double reflection
Emin Emax dmin dmax N c Gamma Thick80 500 37,284 261,455 106 0,212 0,404 0,51780 500 33,229 233,022 150 0,222 0,436 0,65480 500 29,615 207,681 206 0,231 0,428 0,80480 500 26,395 185,096 363 0,225 0,399 1,24580 300 39,207 164,964 87 0,214 0,468 0,43940 300 34,944 294,054 135 0,211 0,379 0,61740 300 31,143 262,076 187 0,218 0,394 0,76140 300 27,757 233,576 291 0,226 0,392 1,05640 300 24,738 208,175 453 0,227 0,361 1,46140 180 36,746 185,536 100 0,203 0,450 0,470
Total mass = 824 kg
Number of shells = 582
R = 0.17 – 0.56 m 1.02’ – 3.22’
Aeff @ 20 keV 200 keV
cm2 3653 1568
Design 1a
Design 1b
Design 2: Single Reflection
R = 0.09 – 0.45 m
= 1.03’ – 5.125’
Group Emin Emax dmin dmax N c Gamma Thick1 80 200 88,509 259,91 37 0,416 0,494 0,4782 80 200 75,351 221,272 30 0,104 0,606 0,2633 80 200 64,149 167,447 30 0,194 0,651 0,2414 80 200 54,613 142,554 30 0,243 0,636 0,2135 80 200 46,494 121,362 37 0,279 0,594 0,2286 80 200 39,582 116,235 57 0,285 0,478 0,3047 80 200 33,698 98,956 120 0,243 0,434 0,5248 80 200 28,688 74,884 233 0,242 0,383 0,8569 80 200 24,424 63,752 453 0,211 0,390 1,37910 80 200 20,793 54,275 262 2,841 0,339 0,891
Design 2
Total mass = 190 kg
Number of shells = 433
Aeff cm2 @ Mass kg
20 keV 200 keV
Design 2 190 2716 1160
Optionally:
Same design can be used at
F = 75 m, as a real focusing
System, but with a slight loss in effective area.
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 keV 200 keV
Design 1a 2057 13900 2023
Design 1b 824 3653 1568
Design 2 190 2716 1160
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
