Hard Xray Optics: From HEFT to NuSTAR

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Hard X-ray OpticsFrom HEFT to NuSTAR
Columbia Astrophysics Laboratory Jason Koglin,
Jim Chonko, Chuck Hailey, Marcela Stern, David
Windt
Caltech Space Radiation Laboratory Hubert Chen,
Fiona Harrison
Danish Space Research Institute Finn Christensen,
Carsten Jensen, Kristin Madsen
Lawrence Livermore National Laboratory Bill
Craig, Todd Decker, Michael Pivovaroff
European Synchrotron Radiation Facility Eric
Ziegler
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HEFT Optics Design

• Conic-approximation Wolter-I
• 3 optics modules assembled
• 6 m focal length
• 400 mm optic length
• Segmented glass optics
• 300 mm thin substrates
• 1.3 X-ray measured HPD
• W/SiC Multilayers
• 20 70 keV response
• EMAAL Mounting
• zero stack-up error
• 5 sectors/layer
• 5 graphite spacers/sector
• 1.6 mm spacers

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NuSTAR Optics Design

• Conic-approximation Wolter-I
• 3 optics modules
• 10 m focal length
• 400 mm optic length
• Segmented glass optics
• 200 um thin substrates
• 40 HPD goal
• Pt/SiC W/SiC Multilayers
• 5 80 keV response
• EMAAL Mounting
• zero stack-up error
• 8 sectors/layer
• 5 graphite spacers/sector
• narrow (0.75 mm) spacers

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Optics Production Process
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Error-compensating Monolithic Assembly
Alignment (EMAAL)

• Each spacer is machined to the precise radius
  and angle with respect to the optic axis.
• No stack-up errors are propagated throughout
  optic build.
• Multilayer mirror segments are constrained to
  spacers with epoxy.
• Only near net shaped shells required to obtain
  high performance.

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Three HEFT Flight Optics Are Completed Flight
Ready

• Demonstrated use of intermediate mandrel
• Repeatability in dismounting/remounting
• Fast Assembly one layer per day
• Monolithic structure for mechanical robustness

HF3
HF2
HF1
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Calibration Methods
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HF2 8 keV X-ray Calibration
Pencil beam measurements performed every 2.5º
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HF3 LVDT Performance
Continued improvement in substrate production and
mounting quality control
57 HPD
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HEFT Individual SegmentLVDT Performance
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Glass Selection 1st Step

• Perform 11 axial scans over 20 cm glass
  substrate.

• Cut away warped edges analyze central 10 cm.

• Select pieces with lt90 HPD for 2nd Step.

72

• OK

20 cm
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Glass Selection 2nd Step

• Rescan selected substrates with 31 axial scans.

• Analyze left, center right 45 octant sections.

• Select best octant section with lt50 HPD.

• 33

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300 mm Glass Laser Metrology
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300 mm Glass Laser Metrology
Down select glass cut to octant (45) segments
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300 mm Glass Laser Metrology
Best performing octant segments for NuSTAR
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200 mm Glass Laser Metrology
Entire Inventory of 200 mm, quint (72) segment
glass
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200 mm Glass Laser Metrology
NuSTAR down select glass cut to octant (45)
segments
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200 mm Glass Laser Metrology
Best performing octant segments for NuSTAR
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40 Glass Selection Prototype

• Glass specs
• Schott AF45
• 300 mm thick
• 45 degrees
• 115 mm radius
• 32 mirrors

• 360 pencil beam scans _at_ 8 and 40 keV were
  performed every degree.
• Individual scan performance 15-65

• Octant sector performance 35-45
• Overall 8 keV performance 405

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W/aSiC Reflectivity _at_ 40 keV
Measured Reflectivity for Wolter I optic with
W/aSiC multilayers is in good agreement with
theoretical expectation Þ 3.5 Å micro-roughness
measured
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Pt/SiC Multilayer Response
New Pt/SiC multilayers necessary for 70-80 keV
response perform as predicted. Þ 3.0 Å
micro-roughness measured
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From HEFT to NuSTAR