urn:nasa:pds:context:instrument:relab.bd-vnir 1.0 1.11.0.0 Product_Context 2020-04-09 1.0 Post-peer-review version. urn:nasa:pds:context:facility:laboratory.relab instrument_to_facility RELAB Bidirectional Spectrometer Spectrometer Bi-directional Ultraviolet, Visible, and Near Infrared Spectrometer Operating Spectral Range: Nominal (0.32 to 2.55 µm); Possible (0.3 to 2.6 µm) Mode Range (µm) Resolution (nm) Grating Detector Light source A 0.30-0.42 < 1.7 1200 Photomultiplier Xenon B 0.40-0.85 < 1.7 1200 Photomultiplier Halogen C 0.60-1.80 < 3.4 600 InSb Halogen D 1.70-2.60 < 6.8 300 InSb Halogen Sampling Interval: 5 or 10 nm standard, 1 nm minimum. Precision: Instrumental error is less than 1/4 % in reflectance. Geometry: Bidirectional reflectance; Spectral goniometry. Incident and reflected beam can each be varied from normal to 70*. (-10 < i < 70; -70 < e < 70). Phase angle minimum 12*, maximum 140*. Specimen: Particulate specimen or soil (reflectance): Measured horizontal and uncovered (normally rotated slowly). Optimal sample amount is 500 mg. Specimen should be no smaller than 20 mg. Specimen should be no larger than 10 g. Chip or rock (reflectance): Measured horizontal and uncovered on a height-adjustable stage. Smallest reliable spot size is ~1.5 mm. Maximum Specimen diameter is 10 cm (2.5 cm if it is to be spun). Thin section (reflectance or transmittance): Measured horizontal on halon (reflectance) or on an aperture (transmittance). Regions to be measured should be no smaller than 1.5 mm. Surface should be polished and clean (no carbon coating). Reference Standard: Halon (pressed) or Spectralon (by Labsphere). Corrections based on the NBS calibration and relative measurement to diffuse gold (at longer than 2 µm in wavelength) are applied automatically. Light Source: Quartz halogen or Xenon lamp. Oriel monochromator. Optics: Order sorting filters, front surface mirrors, depolarizer, apertures. Typical Run Time: Measurements over a spectral range of 0.32 to 2.55 µm at 5 nm sampling interval take ~2 hours per specimen.