Micro Spectro-Gonio Radiometer

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Institut de Planétologie et Astrophysique de Grenoble
 
Institut de Planétologie et Astrophysique de Grenoble
 
   
 
   
CNRS - Université Grenoble Alpes  
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> CNRS - Université Grenoble Alpes  
  
 
Saint Martin d’Hères, France  
 
Saint Martin d’Hères, France  

Revision as of 08:46, 2 December 2014

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.

sample holders:

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.

Tools and sub-systems:

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]

Bidirectional Reflectance

- 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

Photometry:

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)


Samples

- 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:

Temperature:

- room temperature or heated

- down to -20°C (in cold room)

- down to -40°C (in SERAC environmental cell)


Experiment control:

- 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

Current state of system:

- 0.3 - 2.5 µm range: under develoment


- low temperature: to be tested in cold room down to -20°C


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:

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