SALT PFIS Preliminary Design Review

1
Southern African Large Telescope Prime Focus
Imaging Spectrograph

• Optical Integration and Test Plan
• Eric B. Burgh
• University of Wisconsin - Madison

2
Opto-Mechanical Issues

• Lens mount design
• Sealed triplets, thermal effects, coating issues,
  etc.
• Assembly, alignment, and testing
• Collimator, camera, gratings, etalons, etc.
• Integration with mechanisms

3
Instrument Breakdown

• Optics (Lenses/Filters)
• Gratings
• Fabry-Perot etalons
• Polarimetric components
• Detector Subsystem

4
Optics

• Lens mounting
• Coefficient of thermal expansion
• Fused silica ? 0.5 x 10-6 K-1
• NaCl ? 44 x 10-6 K-1
• Sealed NaCl triplets
• Protection from moisture
• Mounting issues
• AR Coatings
• SolGel/MgF2
• Ruggedness
• Application within mounts

5
Optics (continued..)

• Alignment
• Collimator (degree of collimation, focus travel)
• Camera (focus)
• Transmission / image quality
• Integrated collimator / camera setup
• Various combinations of filters
• (Image quality testing with Detector Subsystem?)
• Slit mask verification
• Measure width, edge roughness, relative slit
  positions to verify within tolerances

6
Grating Tests

• Throughput
• Dispersion
• Scattering
• Reproducibility of a

VPH
Monochromatic beam
a
PMT/CCD
7
Fabry-Perot Etalons

• Initial testing performed at Rutgers University
• Integration with PFIS at UW-Madison
• Assembly with structure
• Alignment with optics
• Sensitivity to degree of collimation

8
Polarimetric Components

• Repeatability of wave-plate rotation
• Wave-plate throughput
• Polarimetric efficiency
• Alignment and efficiency of mosaic beamsplitter

9
Detector Subsystem

• Tests that need the Detector Subsystem
• Image quality v. field position
• Field flatness/distortions
• Instrumental scattered light
• Detector pixel scale
• Grating resolution
• End-to-end throughput/detection efficiency

10
Integration

• Mechanism mechanical integration
• Control system integration
• Verification of reproducible alignments
• Change out of slits/gratings/filters

11
Required Lab Equipment

• Monochromator
• Continuum and Arc lamps
• Phototubes/CCD detector
• Multiple axis and rotating stages