Micro Spectro-Gonio Radiometer
Laboratory Experiment facility
Facility name:
Micro Spectro-Gonio Radiometer
Location:
Institut de Planétologie et Astrophysique de Grenoble
> CNRS - Université Grenoble Alpes
Saint Martin d’Hères, France
Persons in charge:
- Scientific : Pierre Beck, Assistant Professor & Bernard Schmitt, Research director
- Technical : Olivier Brissaud, Engineer
General description
The new spectro-gonio radiometer currently under developement will be optimized for the measurement at low temperature of bidirectional reflectance spectra, over the visible and near-IR (at least from 400 to 4800 nm), of dark and very small samples (organics, meteorites…) down to about 1 mm3 in volume.
It will have 2 major sample holder configurations:
- Open sample holders (various sizes down to 3 mm diameter, 0.1 mm depth) over the -20°C ─ +20°C temperature range (cold chamber).
- The SERAC environmental cell (-40°C ─ +80°C ) previously described with a set of sample holders (small sizes) adapted to this new setup.
A number of sample preparation tools and experiment sub-systems are available to the facility:
- For samples preparation: another cold chamber (down to -20°C), set of sample holders, several specific tools for ice sample preparation, set of sieves, grinders, mortars, saw, balances, microscope, owen, ultra-pure water, several pure gasses, wet chemistry materials a, several owens (up to 1200°C) for sample treatments.
- For the experiment: a thermodynamic volumetric system with high accuracy pressure gauges (10-6 to 1 bar), a flow meter (1-10 sccm) and pumps. He-Ne laser + detectors, camera for sample monitoring, …
Technical characteristics:
Spectral range : 0.3 - 4.5 µm (-> 4.8 µm: lower S/N) (4.2-4.3µm: atm. CO2 limited)
Spectral resolution : variable
- mini: < 0.1 nm (but S/N limited)
- maxi: 6 nm (<750nm), 12 nm (<1500nm), 24 nm (<3000nm), 48nm (>3000nm) [May change with future new monochromator]
- Incidence angle: 0° to 85° ; resolution: 0.1° ; maximum sampling : 0.1°
- Emergence angle: 0° to 80° for dark / fine grained samples ; resolution : ± 2° (may be reduced to < ± 0.5°, but S/N limited) ; max. sampling : 0.1°
- Azimuth angle: 0° to 180° ; resolution : ± 2° (may be reduced to < ± 0.5°, but S/N limited) ; max. sampling : 0.1°
- Phase angle: mini to 165° ; mini : ~ 4° for dark / fine grained samples
- Illumination diameter (nadir): 2 mm - Observation diameter (nadir): 20 mm
Absolute: [will be determined during calibration and test phase end 2015 - 2016]
- 0.3-1.0 µm: expected better than 1% over all configurations (relative to a calibrated Spectralon 0.99 reference panel)
- 1.0-2.5 µm: expected better than 1% over all configurations
- 2.5-4.5 µm : expected better than 2% over all configurations
Relative :
- better than 0.5% (0.3-2.5 µm)
- Types: rocks, minerals, (from very bright to dark)
- Texture: compact or granular
- Grain size: sub-µm to a 200 µm
- Size:
maxi: 20mm diameter, 5 mm deep (for dark or fine grained samples)
mini: 4 mm x 20 mm (for principal plane observation down to 80°) OR 4 mm x 8 mm (for principal plane observation down to 60°)
[[File:|500px]]
Picture:
[[File:|500px]]
Picture:
- room temperature or heated
- down to -20°C (in cold room)
- down to -40°C (in SERAC environmental cell)
- PC/Windows, fully software controlled (LabView©). Automatic acquisition of all spectral/geometric configurations
Acquisition time: [will be determined during calibration and test phase end 2015 - 2016]
- typical: 1 mn for 200 spectral channels in visible (S/N dependent)
- total: <1 hour for 100 spectral channels and 100 geometries
- 0.3 - 2.5 µm range: under develoment
- low temperature: to be tested in cold room down to -20°C
- Characteristics: File:Micro-Spectro-Gonio characteristics.pdf
- Article: [[File:]]
Availability to community: [after 2017]
- Technical improvements/calibration (20%)
- IPAG + associated laboratories measurements (60%)
- open as facility or to specific collaborations w. funding (20%)
References:
