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Development of precision hard X-ray multilayer optics with sub-arcminute performance. X-ray Instruments. Science Goals. Columbia Astrophysics Laboratory Jim Chonko, Chuck Hailey, Jason Koglin , Mike Sileo, Marcela Stern, David Windt, Haitao Yu - PowerPoint PPT Presentation
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X-ray InstrumentsX-ray Instruments
Development of precision hard X-ray multilayer Development of precision hard X-ray multilayer optics with sub-arcminute performanceoptics with sub-arcminute performance
Optics Assembly ApproachOptics Assembly Approach• Graphite spacers are epoxied onto a mandrel and machined to the correct radius and angle.
• Coated glass substrates are epoxied to the spacers.
• After epoxy cure, the next layer of spacers is epoxied to the previous layer of glass.
• These spacers are machined and another layer of glass is epoxied to the spacers.
• In a similar way, subsequent layers are added to the optic.
Thermally Formed GlassThermally Formed GlassQ u ar tz M an d re l
a ) c )
G lass M icrosh e e t
b ) d )
Multilayer CoatingsMultilayer Coatings Enhanced reflectivity from multiple interfaces of two materials with large optical contrast (e.g. W/Si).
Metrology Metrology TechniquesTechniques
Non-focusing Detectors:• Previous instruments for hard X-rays: coded aperture (e.g. GRATIS) and collimated. • Detector background determines the minimum detectable X-ray flux. • Detector area Collecting area
Focusing Telescopes:• Soft X-ray telescopes (e.g., ASCA, Chandra) focus via total external reflection.• Crit 1/Energy very small incidence angles are required for hard X-rays.• Detector area << Collecting area• Improved imaging capability
NASA/CXC/SAO
• Glass microsheets (originally developed for the flat panel industry) are positioned on a Quartz mandrel in a commercially available oven.
• As the oven is headed, the glass slowly assumes the large scale figure of the mandrel
• The process is terminated just before it touches the mandrel by decreasing the oven temperature.
• Near net shaped optic substrates are produced without perturbing the excellent initial X-ray properties of the glass micro-sheet (~3.5 Å roughness), even without the aid of highly polished and very expensive mandrels.
• The formed shells are cut to the appropriate size – this also removes the curled edges
Columbia Astrophysics LaboratoryJim Chonko, Chuck Hailey, Jason Koglin, Mike Sileo, Marcela Stern, David Windt, Haitao Yu
Caltech Space Radiation LaboratoryHubert Chen, Fiona Harrison
Danish Space Research InstituteFinn Christensen, Carsten Jensen
Lawrence Livermore National LaboratoryBill Craig, Todd Decker, Kurt Gunderson
Science GoalsScience Goals• Imaging and spectroscopy of 44Ti emissions in young Supernova remnants
• Sensitive observations of obscured Active Galactic Nuclei (AGN)
• Spectroscopic observations of accreting high-magnetic field pulsars
• Mapping the Galactic Center
Correspondence: [email protected], http://astro.columbia.edu/~koglin
This work is supported in part by several NASA grants.
A new generation of hard X-ray telescopes using focusing optics are required to dramatically improve the sensitivity and angular resolution at energies above 10 keV
a) Lay down and machine graphite spacers
b) Lay down glass
c) Lay down and machine graphite spacers
d) Lay down glass
Assembly MetrologyAssembly MetrologyThe Spacers are machined very flat and uniform. The ~1.5 m peak to valley spacer roughness is typically on a millimeter length scale, much shorter than the scale at which the glass can be deformed.
The conformance of the glass directly on top of these spacers is superb (24" figure). Much of this can be attributed to the intrinsic figure of the substrate (~60") and not to errors in the assembly process, which is estimated to be only 8".
0 5 1 0 1 5 2 0
-2 0 0-1 0 0
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O p t ic a l A x is [cm ]
A z im u th a l A x is [d eg re e ]
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0 2 4 6 8 1 0A x ia l L e n g th [c m ]
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Prototype DevelopmentPrototype DevelopmentSeveral prototypes were built in two-bounce configurations with various size and thickness of AF45 and D263 glass – segments were cut to either 5 or 10 cm long and ~5 cm arclength (~35).• Sample LVDT measurements are shown for each type of glass• The results of X-ray pencil beam scans are also shown for each prototype with the Half Power Diameter (HPD) indicated.• The individual performance results for the 34 segments in the 10 cm x 300 m prototype are histogramed – this length and type of substrate has been adopted for HEFT.• The 200 m thick glass meet the Con-X HXT angular resolution requirement – in addition, these substrates are light enough to meet the severe weight restriction of this mission.• The performance of our thermally formed substrates is largely limited by axial bows that are introduced in the forming process – in this way, shorter segments yield improved performance.
A two-bounce prototype optic with three full layers was built & characterized with three separate metrology techniques – LVDT surface metrology, & X-ray pencil beam scans, full illumination with UV – all yielded consistent results.
10 cm long, 300 10 cm long, 300 m thick substratesm thick substrates 5 cm long, 300 5 cm long, 300 m thick substratesm thick substrates
10 cm long, 200 10 cm long, 200 m thick substratesm thick substrates
NASA/CXC/SAO/RutgersJ.Hughes
NASA/CXC/SAOH. Marshall et al.
F. R. Harnden (CfA)
GRANAT
0 5 10 15 20 25 30
Azimuth [degree]
Optic Axis [cm]5
67
89
10
-15-10-5
05
1015
Hei
ght
[m
]
0 50 100 150Performance [arcsec]
0.0
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0.4
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1.0
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ctio
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osed
-10 -5 0 5 10Optic Axis [cm]
-15
-10
-5
0
5
10
15
Hei
ght
[m
]
b)
a)
c)
Upper SegmentsLower Segments
HPD = 45"
X-ray data for 5 cm, 300 m segments
-6-4-20246
Hei
ght
[um
]
0 50 100 150Performance [arcsec]
0.0
0.2
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-10 -5 0 5 10Optic Axis [cm]
-10
-5
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5
10
Hei
ght
[um
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0 5 10 15 20 25 30
Azimuth [degree]0
24
68
10Optic Axis [cm]
b)
a)
c)
Lower Segment Upper Segment
HPD = 58"
X-ray data for 10 cm, 200 m segments
0 5 10 15 20 25 30
Azimuth [degree]10
1214
1618
20Optic Axis [cm]
-6-4-20246 c)
0 50 100 150Performance [arcsec]
0.0
0.2
0.4
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1.0
Fra
ctio
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0 5 10 15 20 25 30
Azimuth [degree]-10
-12-14
-16-18
-20Optic Axis [cm]
-6-4-20246
Hei
ght
[um
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b)
c)
-20 -10 0 10 20Optic Axis [cm]
-15
-10
-5
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5
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Hei
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[um
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a)
Lower Segments Upper Segments
HPD = 54"
Hei
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[um
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Performance [arcsec]
0
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25 45 65 85 105
125
14535 55 75 95 115
135
155
d)
e)
X-ray data for 10 cm, 300 m segments
LVDT data for 10 cm, 300 m segments
Broad-band energy response by using a range layer thicknesses.
