Transcript Slides

Soft X-ray and X-ray multilayers
for Chinese Telescopes
Zhanshan Wang
Institute of Precision Optical Engineering (IPOE)
School of Physics Science and Engineering
Tongji University, Shanghai 200092, China
Outline
 Soft X-ray Polarimetry with LAMP
 Multilayers for LAMP
 X-ray Timing and Polarization(XTP) project
 Depth-graded multilayers for XTP
 Summary and outlook
In the late 1970’s Chinese Academy of Sciences
launched a X-ray telescope project and in the early
1980’s, it was cancelled.
There were nearly no any experience in China
on making grazing incidence X-ray telescopes
In 2004, the plan for exploring Moon was started.
In 2007, a EUV telescope worked on the Moon was planned.
On Dec. 2, 2013, the EUV telescope was launched and now is in the orbit.
[email protected] for He-II , [email protected] for He-I
A EUV telescope on the moon
30.4nm imaging of magnetosphere
58.4nm light from ionsphere
[email protected] for He-II , [email protected] for He-I
1
periodic Mg/SiC multilayer
aperiodic Mg/SiC dual-function multilayer
[email protected],[email protected]
(a)
Reflectivity
0.1
0.01
1E-3
1E-4
20
30
40
50
Wavelength (nm)
60
70
Soft X-ray Polarimetry with LAMP
Lightweight Asymmetry and Magnetism Probe (LAMP)
LAMP is in the framework of a small satellite
unpolarized
E
polarized
Soft X-ray Polarimetry with LAMP
Science with LAMP
• Pulsars
– To measure the geometry of B-field
– To constrain the equation of state
– Be able to identify “bare quark stars”
• Relativistic jets in Blazars
– To measure the B-field in the X-ray jet
• Black hole binaries and active galactic nuclei
– To measure the disk inclination and help constrain BH spin
Multilayers for LAMP
Soft X-ray
Y
Using multilayer mirrors
working at ~250 eV
Parabolic
Surface
θ
Camera
p/2
P
Surface A
O
Total collection area :
1300cm2
201.39
40°
286.03
X
50°
Multilayers for LAMP
Multilayers for LAMP
The incident angle is different
at different positions of the surface
incidence angle(degree)
52
50
field:0 degree
48
46
44
42
At central field, the incident
40
angle is in the range from 40
38
200
220
240
260
X-coordinate(mm)
280
300
to 50 degrees
Multilayers for LAMP
1
3.91
3.27 3.32 3.37 3.43 3.48 3.55 3.61 3.68 3.75 3.83
Cr/C multilayer
Reflectivity
0.1
0.01
N=120
1E-3
D=3.27-3.91nm
1E-4
Rs=23%~26%~31%
1E-5
at =0.45-0.4-0.3nm
1E-6
1E-7
38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
Incidence Angle(deg)
Multilayers for LAMP
0.010
0.27%
Magnetron Sputtering
Target size
125mm450mm
D/D
0.005
0.000
-0.005
-0.010
0
20
40
60
80
100
120
X position (mm)
140
160
180
200
Multilayers for LAMP
Near-normal Incidence Reflectance
Cr/C multilayers，D=2.3nm
0.14
N=250
N=300
0.12
Reflectance, R (a.u.)
Reflectance, R
E=8.05keV
N=150
N=200
N=250
0.10
0.08
0.06
0.04
0.02
N=300
0.00
44.2
0
1
N=200
N=150
2
3
4
44.4
44.6
44.8
45.0
45.2
45.4
Wavelength,  (angstrom)
Grazing Incidence Angle,  (degree)
Multilayers for LAMP, D=3.27-3.91nm
period is larger than that at normal incident
The multilayers were made for LAMP and are waiting for
polarization measurements
X-ray Timing and Polarization(XTP) project
The X-ray Timing and Polarization (XTP) mission, proposed
by IHEP, is currently being developed in China to explore
some main physical problems by observing the Black Holes
and other compact objects.
X-ray Timing and Polarization(XTP) project
X-ray
rut
ruo
rub rlt
rlo
rlb
f
Optical axis
Lp
Lh
2g
Focal
plane
detector
E=2-30 keV, f=4m
Primary
Secondary
It is very important to increase sensitivity in this energy band
Lp
Segmented and highly nested conical approximation to a Wolter I geometry
Depth-graded multilayers for XTP
Design of depth-graded multilayers
Key parameters
X-ray
rut
ruo
rub rlt
rlo
Emax=30 keV
f
Optical axis
Lp
Lh
2g
Primary
Lp
rlb
Secondary
Focal
plane
detector
f =4m
Bilayer thickness = 2.5 nm
Bragg Law: 2dsin = 
Depth-graded multilayers for XTP
Design of depth-graded multilayers
Merit functions
Keys of design
Optimized algorithms
Starting structures
Merit functions:
m
M F   [ R s ( j )  R 0 ]2
j 1
Rs(j): reflectivity of each photon energy point
R0 :
reflectivity target value
Depth-graded multilayers for XTP
Design of depth-graded multilayers
Optimized algorithms
1 simulated annealing algorithm
SA is a global optimization algorithm
However, slow convergence and long calculation time
Some modifications
a) Using more sophisticated new solution generation mechanism
How to determine the new multilayer structure
b) Annealing schedule in an optimized layer-thickness range
How to optimize: which way
The good results can be obtained in short time
Depth-graded multilayers for XTP
Design of depth-graded multilayers
Optimized algorithms
2 Random search method
Thickness of each layer: random change
Some good results: long time
3 Local optimized algorithms
Short time, sometimes good results
Design results: starting structures
Depth-graded multilayers for XTP
Design of depth-graded multilayers
Starting structures
1 Power law progression of bilayer thicknesses
2 Multilayer stacks with a varieties of periods
Depth-graded multilayers for XTP
Design of depth-graded multilayers
Table. Design parameters of XTP
Focal length
4m
Outer Diameter
170 mm
Inner Diameter
60 mm
Mirror length
20 cm
Mirror thickness
Number of nested shells
Energy range: 2-30 keV
0.2 mm
62
Depth-graded multilayers for XTP
Design of depth-graded multilayers
Number of groups
Grazing incident angles
2 groups
0.20°, 0.30°
4 groups
0.15°, 0.20°, 0.25°, 0.30°
6 groups
0.15°, 0.18°, 0.21°, 0.24°, 0.27°, 0.30°
8 groups
0.15°, 0.17°, 0.19°, 0.21°, 0.23°, 0.25°, 0.27°, 0.30°
10 groups
0.15°, 0.16°, 0.17°, 0.18°, 0.20°, 0.22°, 0.24°, 0.26°, 0.28°, 0.30°
12 groups
0.15°, 0.16°, 0.17°, 0.18°, 0.19°, 0.20°, 0.21°, 0.22°, 0.24°, 0.26°,
0.28°, 0.30°
14 groups
0.15°, 0.16°, 0.17°, 0.18°, 0.19°, 0.20°, 0.21°, 0.22°, 0.23°, 0.24°,
0.25°, 0.26°, 0.28°, 0.30°
16 groups
0.15°, 0.16°, 0.17°, 0.18°, 0.19°, 0.20°, 0.21°, 0.22°, 0.23°, 0.24°,
0.25°, 0.26°, 0.27°, 0.28°, 0.29°, 0.30°
Depth-graded multilayers for XTP
Design of depth-graded multilayers
Depth-graded multilayers for XTP
Design of depth-graded multilayers
Depth-graded multilayers for XTP
Fabrication of supermirrors
Magnetron Sputtering systems
X-ray Timing and Polarization(XTP) project
There are mainly two ways to build highly segmented nested optics
The main process for making depth-graded multilayers
is different between NuSTAR and Astro-H
The depth-graded multilayers used in NuSTAR
were deposited on slumped glass shells
The depth-graded multilayers used in Astro-H
were deposited on cylindrical glass mandrels
X-ray Timing and Polarization(XTP) project
New Magnetron Sputtering Coater
Deposition on slumped glass shells
on cylindrical glass mandrels
Depth-graded multilayers for XTP
XE－100 atomic force microscope
D1 X-ray diffractometer
made by Bede Company
X-ray reflectometer in SR
Depth-graded multilayers for XTP
Depth-graded multilayers for XTP
Comparison of different designs
Depth-graded multilayers for XTP
Correction of the deposition rate
Depth-graded multilayers for XTP
Schematic of replication of a multilayer
Depth-graded multilayers for XTP
The reflectivity of a
multilayer after replication
The reflectivity of a
multilayer before replication
Depth-graded multilayers for XTP
Primary results about performance of depth-graded multilayers
with power law progression of bilayer thicknesses
W/Si multilayer
Thickness distribution
Grazing angle =0.3degrees
Depth-graded multilayers for XTP
Primary results about performance of depth-graded multilayers
with power law progression of bilayer thicknesses
W/Si multilayer
Thickness distribution
Grazing angle =0.35degrees
Depth-graded multilayers for XTP
Primary results about performance of depth-graded multilayers
with power law progression of bilayer thicknesses
W/Si multilayer
Thickness distribution
Grazing angle =0.4degrees
Summary and outlook
The LAMP and XTP multilayer mirrors have been
designed and primarily fabricated.
The primary experimental results were obtained
Improving the performance of mirrors and
making prototype for LAMP
Improving the performance of mirrors and
making prototype of a telescope for XTP
Acknowledgements
• IPOE multilayer group, Tongji University, China
• BSRF Soft X-ray Group,China (M.Q.Cui, L.J.Sun, J. Zhu)
• NSRL Spectral Radiation Standard and Metrology (H.J.Zhou)
Strategic Priority Research Program on Space
Science, the Chinese Academy of Sciences
Natural Science Foundation of China
National 863 High Technology Program