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Hard X-ray Optics:From HEFT to NuSTAR: 

Hard X-ray Optics: From HEFT to NuSTAR Caltech Space Radiation Laboratory Hubert Chen, Fiona Harrison Columbia Astrophysics Laboratory Jason Koglin, Jim Chonko, Chuck Hailey, Marcela Stern, David Windt 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

HEFT Optics Design: 

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

NuSTAR Optics Design: 

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

Optics Production Process: 

Optics Production Process

Error-compensating Monolithic Assembly & Alignment (EMAAL): 

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.

Three HEFT Flight Optics Are Completed & Flight Ready: 

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 HF1 HF2 HF3

Calibration Methods: 

Calibration Methods

HF2: 8 keV X-ray Calibration : 

HF2: 8 keV X-ray Calibration Pencil beam measurements performed every 2.5º

HF3 LVDT Performance : 

HF3 LVDT Performance Continued improvement in substrate production and mounting quality control 57” HPD

HEFT Individual SegmentLVDT Performance: 

HEFT Individual Segment LVDT Performance

Glass Selection: 1st Step: 

Glass Selection: 1st Step Perform 11 axial scans over 20 cm glass substrate. 20 cm 72° Cut away warped edges & analyze central 10 cm. Select pieces with <90” HPD for 2nd Step. OK

Glass Selection: 2nd Step: 

Glass Selection: 2nd Step Rescan selected substrates with 31 axial scans. Analyze left, center & right 45° octant sections. Select best octant section with <50” HPD. 33”

300 mm Glass Laser Metrology: 

300 mm Glass Laser Metrology

300 mm Glass Laser Metrology: 

Down select glass cut to octant (45°) segments 300 mm Glass Laser Metrology

300 mm Glass Laser Metrology: 

Best performing octant segments ® for NuSTAR 300 mm Glass Laser Metrology

200 mm Glass Laser Metrology: 

Entire Inventory of 200 mm, quint (72°) segment glass 200 mm Glass Laser Metrology

200 mm Glass Laser Metrology: 

NuSTAR down select glass cut to octant (45°) segments 200 mm Glass Laser Metrology

200 mm Glass Laser Metrology: 

Best performing octant segments ® for NuSTAR 200 mm Glass Laser Metrology

40” Glass Selection Prototype: 

40” Glass Selection Prototype 360 pencil beam scans @ 8 and 40 keV were performed every degree. Individual scan performance: 15-65” Glass specs Schott AF45 300 mm thick 45 degrees 115 mm radius 32 mirrors Octant sector performance: 35-45” Overall 8 keV performance: 40±5”

W/aSiC Reflectivity @ 40 keV: 

W/aSiC Reflectivity @ 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

Pt/SiC Multilayer Response: 

Pt/SiC Multilayer Response New Pt/SiC multilayers necessary for 70-80 keV response perform as predicted. Þ 3.0 Å micro-roughness measured

From HEFT to NuSTAR: 

From HEFT to NuSTAR