Adaptive X-Ray Optics with a Deformable Mirror

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Adaptive X-Ray Optics with a Deformable Mirror

• Shunji Kitamoto,a,b, Norimasa Yamamotob,
  Takayoshi Kohmurab.c, Kazuharu Sugaa.b , Hiroyuki
  Sekiguchia,b, ,Junichi Satoa, Keisuke Sudoa,
  Takeshi Watanabea, Youhei Ohkuboa, Akiko
  Sekiguchia and Masahiro Tsujimotoa
• Rikkyo University, 3-34-1, Nishi-Ikebukuro,
  Toshima-ku Tokyo, 171-8501, Japan

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Abstract

• We started development of an ultra high precision
  X-ray Telescope using adaptive X-ray optics,
  named X-ray milli-arc-sec Project (X-mas
  Project).
• I will report our current activity of this
  project.

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OUTLINE

• Introduction
• Telescope Design
• Components
• Primary Mirror
• Deformable Mirror
• Wave Front Sensor
• Back side CCD
• Optical Blocking Filter
• X-ray Source
• Conclusion

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1. Introduction

• X-ray Astronomy Satellite Chandara was launched
  in July 1999 and it has 0.5 arc-sec resolution.
• Chandra is providing us wonderful X-ray images
  and we are enjoying lots of important scientific
  results.
• However, the current achievement of the image
  quality is still far from the theoretical
  diffraction limit!

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1.Introduction
Telescopes plotted on the wave length-diameter
plane

• If we have a diffraction limit X-ray telescope
  with 1 m diameter, the resolution will be less
  than 1 milli-arc-sec.

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What is the problem?

• Requirement of Small-scale Roughness several Å
• Requirement of Large-scale Figure Error 1nm

Easy
very difficult
(1) optical monitoring of the optics
(2) adaptive optics system with a deformable
mirror
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Some Technical Consideration

• A normal incident telescope is easier than the
  grazing incident telescope, in order to have a
  large effective area.
• Possible precision of the shape measurement is a
  few nm.

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Test Configuration
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Primary Mirror

• Off Axis Paraboloid
• D80mm
• f2000mm
• The diffraction limit is 41 milli-arc-sec

80mm
Shinsedai Kakou System X-ray Company
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Secondary MirrorDeformable Mirror (DFM)

• 31 elements-Bimorph piezo-electric plates
• two layer piezos with the opposite polarity.
• Each plate can make a curvature of concave or
  convex shape.
• 55mmf effective diameter

CILAS
Bimorph piezo-electric plates
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Flat plane made by DFM

• Using Zygo Interferometer
• 5.26nm rms flat plane had been achieved.

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Mo/Si Multi-Layer Coating on DFM

• Surface Roughness
• rms 0.321nm
• Figure Error
• 5.9 nm rms
• (after remove tilt and sphere)

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Optical Image of Current Telescope
Optical Image of a anode-cap shined by a filament

• No adaptive Optics
• No tuning
• wrong optics

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Wave Front Sensor

• HASO32 (Imagine Optic)
• Shack-Hartmann Sensor
• consist of a Micro-lens array and CCD

cartoon of HASO32
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Precision of the Wave Front Sensor

• Spherical wave is constructed by a pin hole with
  1 m m diameter.
• Remove the tilt and spherical component form
  obtained wave shape.
• Calculate the residuals and rms variation

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Wave front Control with Optical Light
Confirm the closed loop control
all biases are 0 V 0.143 mm, (rms)
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X-ray Detector

• Back-illumination CCD (HPK)
• 30 detection efficiency at 13.5nm
• 512x512 pixels
• 24 mm square
• Expected image size is 0.3 mm
• We have to study a sub-pixel read-out method
• and/or
• we need a X-ray detector with finer position
  resolution.

Image of 55Fe X-rays
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Optical Blocking Filter

• 2 x 150nm Zr
• Optical transmission 10-9
• 13.5nm Transmission 0.25

Transmission of 100nm Zr
UV blocked by SiO2
from Luxel
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Optical Blocking Filter

• Measurement of the X-ray transmission at KEK-PF.

45 transmission at 13.5nm
Transmission of two filters is 20
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X-ray Source

• Manson Ultrasoft X-ray Source (Model-2)
• Anode Cap Al/Si alloy
• Si 16.4
• 13.55nm Si L transition

Home-made monochrromator
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Conclusion

• All the components are almost prepared.
• Optical closed loop system has been demonstrated.
• X-ray source is now ready.
• However, current precision is far from the goal
• Next step
• fine tuning/alignment of the components
• the X-ray imaging with adaptive optics.

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Plan

• Propose the X-mas satellite mission in futur
• Try to challenge the shorter wave length and
  larger diameter

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• Thank you for attention.

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X-ray Optical Separation Filter

• Zr filter has a good transmission

Zr 150nm On the donuts-shape frame with a few A
surface roughness and 5nm rms figure error.
20mm
X-ray Company Luxel
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Testing the precision of the wave front sensor

• Installed in a clean booth covered by a Black
  Curtain

Laser source with pin hole
Wave Front Sensor
Imagine Optic
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X-ray landing position and its event pattern
X???????????????????????????????
1 pixel
???????????X?????????
???????? ??????????????????
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X-ray Detection on a CCD
CCD?????
X?
??
Single event
Corner event
???
Horizontally split event
Vertically Split event
???
CCD??????
???X?????????????????????????????????? ???X???????
???????????? X?????????????????????????????
Hiraga
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2.Design for Laboratory Experiment
The primary mirror has 80mm diameter and 2000mm
focal length. The optical source, deformable
mirror, wave front sensor, make it possible to
monitor the shape of the telescope and the
adaptive feedback system.
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3. ???????????
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X-ray Source

• Measure the reflectivity of known Mo/Si
  multilayers (2d26nm)
• Clear peak at the incident angle of 33 deg.