Pay for Performance (“P4P”) Bangkok December 2009 December 2009.
AXRO, DECEMBER 2009
-
Upload
vielka-schultz -
Category
Documents
-
view
32 -
download
1
description
Transcript of AXRO, DECEMBER 2009
AXRO, DECEMBER 2009 1
X-ray Optics:
Wolter versus KB system
Veronika Marsikovaa, Libor Sveda b, Adolf Inneman a,
Jiri Marsik a, Rene Hudecc, Ladislav Pinab
a) Rigaku Innovative Technologies Europe, s.r.o.
b) Czech Technical University in Prague, FNSPE
c) Astronomical Institute of Academy of Sciences of Czech Republic
AXRO, DECEMBER 2009 2
Motivation
• Manufacturing Wolter system needs very
expensive mandrels (3D aspheric).
• Manufacturing KB system can be easier and
cheaper (2D aspheric).
• Substrates can be glass and/or silicon with
excellent flatness and micro-roughness which
is necessary for long focus optics.
AXRO, DECEMBER 2009 3
Wolter system
• Double reflection X-ray Optics - Wolter type I optics consists of rotationally symmetric mirrors which are parabolic mirror followed by a hyperbolic mirror.
• Set of nested mirrors is arranged concentrically to the optical axis. Each ray coming is reflected at the parabolic surface first, then at the hyperbolic surface.
• The quality of the focal spot image of the X-ray source depends on quality of substrates (shape, microroughness).
• Optical error is rectified (astigmatic and coma error).
• Replicated technology requires very expensive mandrel.
XMM
http://imagine.gsfc.nasa.gov
horizontal focusing mirror
vertical focusing mirror
AXRO, DECEMBER 2009 4
KirckPatrick Baez system
• Double reflection X-ray Optics consists of two mirror sets – one is aligned vertically and the second is aligned horizontally.
• Both mirrors have to be curved parabolically – the first mirror focuses in vertical plane and the second mirror focuses in horizontal plane. Single focal point is formed in the crossection of the two focal planes.
• The quality of the focal spot image depend on quality of substrates (shape, microroughness).
• Technology is not necessarily based on precise and expensive mandrel.
• Classic technologies for laboratory KB-mirrors are expensive, complicated and based on heavy optics.
http://imagine.gsfc.nasa.gov/
http://www.x-ray-optics.de
AXRO, DECEMBER 2009 6
ComparisonKB W
Type of optics Parabolic-parabolic planar Parabolic-hyperbolic rotational
Number of reflections 2 2
Focal length - Aperture20 m – 913 x 913 mm
40 m – 1826 x 1826 mm10 m – dia 913 mm
20 m – dia 1826 mm
First mirror134 mm from axis268 mm from axis
134 mm from axis268 mm from axis
Number of mirrors420 840
394 788
Length of substrate 300 mm 300 mm
Material substrate silicon glass
Surface gold gold
AXRO, DECEMBER 2009 7
Focal length
W system
KB system
If W and KB have the same aperture, focal length of KB system is
twice as large as Wolter system.
L
2L
AXRO, DECEMBER 2009 8
Input conditions• Minimum distance between mirrors: 1 mm• Energy range: 1.0 – 10.0 keV• Last mirror reflection:
70% reflection (after 1st reflection @ 1keV)
50% reflection (after 2nd reflection @ 1keV)
AXRO, DECEMBER 2009 10
Reflectivity at first mirror set
(Focal length 10m KB and 20m W)
KB systemW system
AXRO, DECEMBER 2009 11
Source spectrum
• Crab Nebula
Images of Crab Nebula from Chandra X-ray Observatory. Physics News Graphics, AIP.
http://chandra.harvard.edu/photo/0052/index.html
]///1[)( 2)1( HzscmAS
2
Toor & Seward (1974)
Focal length optimization
AXRO, DECEMBER 2009 18
• “ideal” focal length for both sets results in asymmetric peak
• focal length of mirror set one was optimized
• Difference ideal-optimal ~ 4 mm
Next year enhancements
• Reflectivity efficiency maps.
• Segment based KB design as a result of efficiency maps (flower-like KB).
• Comparison to standard designs.
AXRO, DECEMBER 2009 19
AXRO, DECEMBER 2009 22
RITE technologies
• Based on industrial substrates (glass and or Si wafer) with very
good surface quality (shape, microroughness) => low cost.
• Technology process retains surface quality and polishing
process is not needed.
• Technology allows composite materials and/or relatively light-
weight materials.
• Cubic geometry means easer assembling of the system.
Gorenstein, Paul,Proc. SPIE Vol. 3444, p. 382-392
ISRO Meeting Prague, October 2009 23
MFO technology
X-ray optics–Substrates
•Glass•Silicon•Nickel
–Type of optics•KB system•Lobster Eye
AXRO, DECEMBER 2009 25
Si substrates
Analysis of formed Si wafer by TH profilometer.
Analysis of formed Si wafer by AFM.
Comparison of convex side of bent Si wafers (left) and flat Si wafer (right)
AXRO, DECEMBER 2009 26
RITE modules
•Model based on ray-tracing (11 profiles)
•Two sets of mirrors from Si chips 100x100x0.525 mm
•Total optics length 600 mm, aperture 40x40 mm
AXRO, DECEMBER 2009 28
Conclusion
• KB vs. W
• Comparable effective area at f=2*f
• KB has more homogeneous intensity
• KB has comparable angular resolution
• KB samples manufactured from multiple small Si chips
(substrates)
• Tests are expected at the beginning of 2010
• Future enhancements of KB (simulation + manufacturing
– silicon and glass substrates)
AXRO, DECEMBER 2009 29
Acknowledgment• We acknowledge support of:
• Grant Ministry of Education, Youth and Sports, grant
“Applications of Kirkpatrick Baez Imaging Systems in
Space”, No. ME09004.
• Grant ESA - PECS, grant “Novel X-ray Optics Technologies
for ESA X-ray Astrophysics Missions”, No. 98039.
• Grant Agency of Academy of Sciences of the Czech
Republic, grant “Material and X-Ray Optical Properties of
Formed Silicon Monocrystals”, No. IAAX01220701.
• Project MSMT INGO “Vyzkum v ramci Mezinarodniho centra
husteho magnetizovaneho plasmatu”.