P1253814641gtDOf

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Expected Improvements in Imaging
G. Pareschi
INAF Osservatorio Astronomico di Brera
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Outline

• Historical remarks on high energy imaging optics
• Hard X-ray focusing telescope Simbol-X
• Wide-field X-ray optics
• Future large size X-ray missions (XEUS)

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X-ray astronomical optics history in pills

• 1895 Roentgen discovers X-rays
• 1948 First succesfull attempt of the
  focalization of an X-ray beam by a
  total-reflection optics (Baez)
• 1952 H. Wolter proposes the use of
  two-reflection optics based on conics for X-ray
  microscopy
• 1960 R. Giacconi and B. Rossi propose the use
  of grazing incidence focusing optics for X-ray
  telescopes
• 1962 discovery by Giacconi et al. of Sco-X1,
  the first extra-solar X-ray source
• 1963 Giacconi and Rossi fly the first (small)
  Wolter I optics to take images of Sun in X-rays
• 1965 second flight of a Wolter I focusing
  optics (Giacconi Lindslay)
• 1973 SKYLAB carry onboard two small X-ray
  optics for the study of the Sun
• 1978 Einstein, the first satellite with
  focusing optics enterely dedicated to X-rays
• 1983 EXOSAT operated (first European mission
  with X-ray optics aboard)
• 1990 ROSAT, first All Sky Survey in X-rays by
  means of a focusing telescope with high imaging
  capabilities
• 1993 ASCA, a multimudular focusing telescope
  with enhanced effective area for spectroscopic
  purposes
• 1996 BeppoSAX, a broad-band satellite with Ni
  electroformed replicated optics
• 1999 launch of Chandra, the X-ray telescope
  with best angular resolution, and XMM-Newton, the
  X-ray telescope with most Effective Area
• 2004 launch of the Swift satellite devoted to
  the GRBs investigation (with aboard XRT)
• 2005 launch of Suzaku with high throughput
  optics for enhanced spectroscopy studies with
  bolometers

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Imaging experiments using Bragg reflection from
replicated mica pseudo-cylindrical optics
E. Fermi Thesis of Laurea, Formazione di
immagini con i raggi Roentgen (Imaging
formation with Roentgen rays), Univ. of Pisa
(1922)

Thanks to Giorgio Palumbo!
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Present Astronomical optics technologies HEW Vs
Mass/geometrical area
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Present Astronomical optics technologies HEW Vs
Mass/geometrical area
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Present Astronomical optics technologies HEW Vs
Mass/geometrical area
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X-ray optics by Ni electroforming replication
BeppoSAX
Jet-X/Swift
XMM-Newton
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X-ray optics by Ni electroforming replication
BeppoSAX
Now the Ni electroforming approach, born and
set-up by Citterio et al. For BeppoSAX is a
technology almost of-the-shelf for small/medium
size missions. It will be used for e-Rosita, SVOM
and Polar-X
Jet-X/Swift
XMM-Newton
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The focusing problem in the hard X-ray region (gt
10 keV)
F focal length R reflectivity L mirror
height q incidence angle
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The focusing problem in the hard X-ray region (gt
10 keV)
F focal length R reflectivity L mirror
height q incidence angle
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The focusing problem in the hard X-ray region (gt
10 keV)
At photon energies gt 10 keV the cut-off angles
for total reflection are very small also for
heavy metals ? the geometrical areas with usual
focal lengths (gt 10 m) are in general negligible
F focal length R reflectivity L mirror
height q incidence angle
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Focal Length Vs. Diameters for SIMBOL-X and other
X-ray telescopes
0.6 o
Aeff ? F2 x qc2 x R2
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Focal Length Vs. Diameters for SIMBOL-X and other
X-ray telescopes
0.6 o
The Formation Flight architecture offers the
opportunity to implement long FL telescopes!
Aeff ? F2 x qc2 x R2
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The formation flight contribution
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The formation flight contribution
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The formation flight contribution
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The formation flight contribution
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Wide band multilayers
X-ray supermirrors
Optical supermirrors in a beetle skin
b)

• Beetle Aspidomorpha Tecta
• TEM section of the skin
• b) Reflectivity in the optical band nel visibile.

CREDITS Dr. Naoyuki Ohnishi Chubu University
Japan Dr. Yasushi Ogasaka Nagoya Univ. - Japan
a)
1 mm
CREDITS Dr. A. R. Parker Dep. Of
Zoology Oxford University UK
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Top-level scientific requirements
Energy band 0.5 80 keV
Field of view (at 30 keV) 12 (diameter)
On-axis effective area 100 cm2 at 0.5 keV 1000 cm2 at 2 keV 600 cm2 at 8 keV 300 cm2 at 30 keV 100 cm2 at 70 keV 50 cm2 at 80 keV (goal)
Detectors background lt 2?10-4 cts s-1cm-2keV-1 HED lt 3?10-4 cts s-1cm-2keV-1 LED
On-axis sensitivity 10-14c.g.s.(0.5 µCrab), 10-40 keV band, 3s, 1Ms,
Line sensitivity at 68 keV lt 3 ?10-7 ph cm-2 s-1 (3s, 1Ms)
Angular resolution 20(HPD), E lt 30 keV 40(HPD) _at_ E 60 keV (goal)
Spectral resolution E/?E 40-50 at 6-10 keV E/?E 50 at 68 keV (goal)
Absolute timing accuracy 100 µs (50 µs goal)
Absolute pointing reconstruction 3? (radius, 90) (2 goal)
Mission duration 3 years including commissioning and calibrations (2 years of scientific program) provision for a possible 2 year extension
Total number of pointings gt 1000 (first 3 years, nominal mission) 500 (during the possible 2 year mission extension)
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Simbol-X core scientific objectives

• Black hole physics and census

• resolve at least 50 of the CXB in the energy
  range where it peaks (20 -30 keV)
• solve the puzzle on the origin of the hard Xray
  emission from the Galactic centre
• constrain the physics of the accretion flow onto
  both SMBH and solar mass BH

• Particle acceleration mechanisms

- constrain acceleration processes in
relativistic Jets of blazars and GRB - probe
acceleration mechanisms in the strong EM and
gravitational fields of pulsars - measure the
maximum energy of electron acceleration in
supernova remnants shocks
These two broad topics define the core scientific
objectives of Simbol-X
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Simbol-X core scientific objectives

• Black hole physics and census

• resolve at least 50 of the CXB in the energy
  range where it peaks (20 -30 keV)
• solve the puzzle on the origin of the hard Xray
  emission from the Galactic centre
• constrain the physics of the accretion flow onto
  both SMBH and solar mass BH

• Particle acceleration mechanisms

- constrain acceleration processes in
relativistic Jets of blazars and GRB - probe
acceleration mechanisms in the strong EM and
gravitational fields of pulsars - measure the
maximum energy of electron acceleration in
supernova remnants shocks
These two broad topics define the core scientific
objectives of Simbol-X
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Implementation Challenges

• Image quality large FOV ? 15 HPD 12 FWHM
  
• High throughput ? 0.3 1 ? 103 cm2 _at_30keV
• Low internal background Rejection of CXB from
  outside the FOV
• Wide energy response (0.5 80 keV) with high
  spectroscopic performances

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Multilayer coated Ni mirror shells tested at
Panter
See S. Romaine et al., SPIE Proc., 5900 (2005)

• N.B. a collaboration SAO/NASA-MSFC/INAF-OAB

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The Simbol-X focal plane assembly

• Spectro-imaging system 0.5-100 keV, fast reading
• Full size 8x8 cm2, 128x128 pixels of 625 mm
• Operation at -40C

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Simbol-X Optics

• Heritage from XMMNewton nickel shells obtained
  by electroforming replication method low mass
  obtained via a reduced thickness of shells

• Coating multi-layer Pt/C needed for requirement
  on large FOV and on sensitivity up to gt 80 keV

Focal length 20 m Shell diameters 30 to 70
cm Shell thickness 0.2 to 0.6 mm Number of
shells 100
N.B. I The optics module will have both sides
covered with thermal blankets
N.B. II a proton diverter will be implemented
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Expected Flux Sensitivity
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Angular resolution for past future Hard X-ray
Experiments
Experiment Year Imaging technique Angular resolution
SAX-PDS 1996 Rocking collimator gt 3600 arcsec (collimator pitch)
INTEGRAL-IBIS 2002 Coded mask 720 arcsec (mask pitch)
HEFT (baloon) 2005 Multilayer optics gt 90 arcsec HEW
NEXT 2013? Multilayer Optics 90-60 arcsec HEW
SIMBOL-X 2013 Multilayer Optics 15-20 arcsec HEW
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Wide Field Polynomial optics
R. Giacconi, AN EDUCATION IN ASTRONOMY, Annu.
Rev. Astro. Astrophys. 2005.43 1- 30, 22
A further extension of this line of thinking is
that experiments could be designed by modelling
both the hardware and software as part of the
initial design. I myself, together with Richard
Burg and Chris Burrows, used this approach in
designing in the 1980s what I believe was one of
the best experiments I ever conceived. The
purpose was to scan the sky and to detect distant
clusters of galaxies through their X-ray
emission. The idea was that it would be possible
to equal or exceed the sensitivity of Chandra
with an X-ray telescope of one tenth the area
(and cost). This could be achieved by dedicating
an entire mission of a small satellite to this
purpose and by designing a telescope that would
have a gt16-fold increase of the field of view
with respect to Chandra. ..
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X-ray optics with polynomial profile

• Mirrors are usually built in the Wolter I
  (paraboloid-hyperboloid) configuration which
  provides, in principle, perfect on-axis images.
• This design exhibits no spherical aberration
  on-axis but suffers from field curvature, coma
  and astigmatism, which make the angular
  resolution to degrade rapidly with increasing
  off-axis angles.
• More general mirror designs than Wolter's exist
  in which the primary and secondary mirror
  surfaces are expanded as a power series, and the
  height-to-focal-length ratio optimized
• These polynomial solutions are well suited for
  optimization purposes, which may be used to
  increase the angular resolution at large off-axis
  positions, degrading the on-axis performances
  (Burrows, Burgh and Giacconi 1992)
• A trade-off of the whole optics assembly of a
  wide-field telescope can further on increase the
  imaging capabilities off-axis of wide-field
  polynomial optics

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WFXT (ASI Phase A study)
Tests _at_ Panter-MPE Marshall XRF
WFXT (epoxy replication on carrier in SiC) Ø
60 cm Focal Length 300 cm HEW 10 arcsec
Ref. O. Citterio, et al., , SPIE Proc., 3766,
198 (1999).
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EDGE-WFI concept (I)
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EDGE-WFI concept (II)
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EDGE-WFI concept (II)
Flux Sensitivity (0.5 2 keV) 1.5 10-16 cgs in
1 Msec
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Geometric Area and Angular resolution for past
and future X-ray telescopes
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XEUS
(3 x10-18) _at_ 0.28 keV 4s
Sensitivity (cgs)
Effective Area
Angular Resolution

• 1 (1.5) m2 _at_ 0.2 keV
• 5 m2 _at_ 1 keV
• 2 m2 _at_ 7 keV
• 1 m2 _at_ 10 keV
• (0.1) m2 _at_ 30 keV

5 (2) arcsec _at_ lt 10 keV 10 arcsec _at_ 40 keV
Field-of-View
7 (10) arcmin diameter WFI, HXI 1.7 arcmin
diameter NFI
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XEUS Effective Area
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XEUS Optics Parameters

• Aperture radii 0.672.1 m
• Grazing reflection angles 0.270.86 deg
• Focal length 35 m
• Plate scale 170µm/arcsec
• Total mirror weight 1.3 tons

Optics error Budget Specifications (arcsec)
Inherent Intrinsic Extrinsic Environment
Total Goal 1.4 1.2 0.5
0.5 2.0 Req. 1.8
3.7 2.0 2.0
5.0
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X-ray Pore Optics System
Double-Cone approximation
N.B.concept introduced by D. Willingale et al,
Capri 1994
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Pore Optics technology
Credits ESA Cosine
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Cellular solids light weight structures with a
very high stiffness
Foamed
Regular cellular structures
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Preliminary imaging tests onto two-reflection
optics (I)
Credits ESA, Cosine, MPE
Collon et al, SPIE Proc 67898, in press (2007)
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Preliminary imaging tests onto two-reflection
optics (II)
Extrapolated HEW for the 4 the first four plates
and the entire stack width (1.2 cm2) of 17
arcsec HEW (BUT JUST IN ONE DIRECTION!)
Creditd Cosine ESA
Extrapolated performance of XOU-3 taking into
account beam spreading At 25 m distance (A) the
azimuthal focussing becomes visible and results
in a focus at 50 m distance (B). The HEW
calculated for the image B (plates 1-4, all 60
pores) is 17 without any corrections
Collon et al, SPIE Proc 67898, in press (2007)
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Alternative approach hot sluping of thin glass
segments
0.4 mm thick segment (without integration) HEW
5 arcsec
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Segment production sequence _at_ INAF-OAB
Ghigo et al, 2006
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Slumping tests on Borofloat33 glass sheets
The use of a vacuum muffle with the capability to
apply on the glass a uniform controlled pressure
(150 g/cm2) provided the best results so far.
The muffle protect the glass from the dust of the
oven and the vacuum avoid the convection of air
slumping (l/11 on 80 mm 50 nm rms) (l/2.9 on 130
mm)
No dust specks Circular fringes very sharp up to
the edge of the glass
150 mm Zerodur K20 mould
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SIMBOL-X