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Alice  Instrument, Optical Details

The Alice optical design consists of:

  • 40 x 40 mm2 off-axis parabolic primary
  • Rowland circle design for the spectrograph
  • Holographic grating by Y. Jobin
  • SiC coated optics on Ni polished surface on Al substrate

Optical Performance Summary

Bandpass 700 - 2050 Angstroms
Spectral Resolution 5.6 Angstroms, point source
12.5 Angstroms, extended source at 700 Angstroms
9.8 Angstroms, extended source at 2050 Angstroms
Spatial Resolution 0.1 x 6.0 degree2
(70 x 420 m2 at 40 km)
Active FOV 0.1 x 6.0 degree2
Nominal Effective Area 0.03 (1900 Angstroms) - 0.53 cm2 (1150 Angstroms)
Nominal Sensitivity 0.5 (1900 Angstroms) - 7.8 (1150 Angstroms) cs-1 R-1
Detector Dark Current Rate 3 - 7 count s-1

Resolving Power Graph

Spectral Resolution vs Slit Width

Predicted resolving power of ALICE for point sources and extended sources (0.1 x 6 deg.2) as a function of wavelength

Point Source Spot Diagrams

Point Source Spot Diagrams

ALICE point source spot diagrams at 700, 1300 and 2000 Angstroms. Pixel size for the (512 x 32)-pixel format is 0.068mm in X-dimension by 0.625 mm in Y-dimension.