Ultra High Precision X-ray Telescope Project

Adaptive X-Ray Optics
with a Deformable
Mirror
Shunji Kitamoto*,a,b, Norimasa Yamamotob, Takayoshi Kohmurab.c,
Kazuharu Sugaa.b , Hiroyuki Sekiguchia,b, ,Jun’ichi Satoa, Keisuke
Sudoa, Takeshi Watanabea, Youhei Ohkuboa, Akiko Sekiguchia and
Masahiro Tsujimotoa
Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku Tokyo, 1718501, Japan
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.
OUTLINE
Introduction
Telescope Design
Components






Primary Mirror
Deformable Mirror
Wave Front Sensor
Back side CCD
Optical Blocking Filter
X-ray Source
Conclusion
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!
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.
What is the problem?
Requirement of Small-scale
Roughness : several Å
Easy
Requirement of Large-scale
Figure Error: ～1nm
very difficult
We are trying to overcome this difficulty by
applying two ideas
(1) optical monitoring of the optics
(2) adaptive optics system with a deformable mirror
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.
13.5nm band is currently best choice.
Mo/Si Multi-Layers have more than 70%
reflectivity for the normal incident mirror.

Test Configuration
All components are in the vacuum chamber and
on a stable table.
Primary Mirror
Off Axis Paraboloid
D=80mm
 f=2000mm
The diffraction limit is
~41 milli-arc-sec

Coating with Mo/Si Multilayers
30-50% reflectivity
Shinsedai Kakou System ＆
X-ray Company
80mm
Secondary Mirror
Deformable Mirror (DFM)
31 elements-Bimorph piezoelectric plates


two layer piezos with the
opposite polarity.
Each plate can make a
curvature of concave or convex
shape.
55mmφ effective diameter
CILAS
Bimorph piezo-electric plates
Flat plane made by DFM
Using Zygo
Interferometer

5.26nm rms flat plane
had been achieved.
Some examples of the deformation
Mo/Si Multi-Layer Coating on DFM
Surface Roughness
rms 0.321nm
Figure Error
5.9 nm rms
(after remove tilt and sphere)
reflectivity
65% for 13.5nm
Optical Image of Current Telescope
Optical Image of a anode-cap
shined by a filament
No adaptive Optics
No tuning

9mm
wrong optics
~0.1mm at 4350mm away from the
primary mirror. ~5 arc-sec
(Diffraction limit for 500nm
~1.5 arc sec)
1mm
Image of the Anode Cap
Wave Front Sensor
HASO32 (Imagine Optic)


Shack-Hartmann Sensor
consist of a Micro-lens array and CCD
cartoon of HASO32
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
We confirm the precision of
Less than 3nm rms
Wave front Control with Optical Light
closed loop control
0.060 mm (rms)
263nm
Confirm the closed loop control
121nm
520nm
all biases are 0 V
0.143 mm, (rms)
187nm
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 readout method
and/or
we need a X-ray detector with finer
position resolution.
Image of 55Fe X-rays
Optical Blocking Filter
Transmission of 100nm Zr
2 x 150nm Zr


Optical transmission
~ 10-9
13.5nm Transmission
~0.25
1
135nm
0.01
Otical
UV blocked
by SiO2
0.0001
from Luxel
10
100
Wave Length(nm)
1000
Optical Blocking Filter
Measurement of the Xray transmission at
KEK-PF.
~45% transmission at 13.5nm
Transmission of two filters is ~20%
X-ray Source
Manson Ultrasoft X-ray
Source (Model-2)

Anode Cap; Al/Si alloy
Si 16.4%
 13.55nm Si L transition

Confirm 13.55nm X-rays
by the measurement of the
reflectivity of a know Mo/Si
Multilayer (2d=26nm)
Home-made monochrromator
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.
Plan
Propose the X-mas satellite mission in
futur
Try to challenge the shorter wave length
and larger diameter
Fukue et al.
Challenge Direct imaging of the Black Holes.
Thank you for attention.
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
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
X-ray landing position and its event pattern
Ｘ線入射位置とそのイベントパターンはどう対応しているのだろうか？
1 pixel
シングルイベント
を作るＸ線入射位
置の分布。
シングルイベント
全電荷が一画素
に集められたイベ
ント。
3×3 pixels
X-ray Detection on a CCD
Ｘ線
CCD平面模式図
電極
Single event
Corner event
電子雲
Horizontally
split event
Vertically
Split event
空乏層
CCD断面の模式図
一個のＸ線光子により生成される信号
を計測するため、入射フラックスは弱
くする。
一個のＸ線光子がつくる電子雲はある
程度広がる。
Ｘ線光子一個を検出したイベントには
2015/9/30
さまざまなパターンがある。
Charge cloud
Event
pixel
Hiraga
phD thesis 2002
Split
pixel
27
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.
3. 望遠鏡の組み上げ真空化
X-ray Source
Measure the reflectivity of known Mo/Si
multilayers (2d~26nm)

Clear peak at the incident angle of 33 deg.

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