Planetary Spectroscopy Laboratory (PSL)

 

Facility name:	Planetary Spectroscopy Laboratory (PSL)
Location:	Institute of Planetary Research DLR – German Aerospace Center Rutherfordstrasse 2, 12489 Berlin, Germany
Persons in charge:	Scientific : Jörn Helbert, Research director & Alessandro Maturilli, Laboratory Manager Technical : Ines Büttner, Sample preparation facility

General description

The Planetary Spectroscopy Laboratory (PSL) is equipped with two Bruker Vertex80V FTIR instruments allowing to measure emissivity, bidirectional reflectance and transmittance spectra of various types of planetary materials (fine powder to granular to compact) over a very wide spectral range under vacuum, purged air or inert gas atmosphere.

Bi-directional reflectance measurements entirely cover the UV to FIR spectral range (0.2 to 150 µm) and can be performed with independent incident and emission angles from 13° to 85°.
Transmittance measurements of pressed pellets and optical filters or windows are measured thanks to a parallel beam accessory (working without refraction and beam shift effects) in the whole 0.2 to 150 µm spectral range.
Emissivity measurements are recorded by using an external emissivity chamber (home-designed) at the Planetary Emissivity Laboratory (PEL) from the visible to the far-IR (from 0.4 to 150 µm), with a high SNR for sample temperatures from 300 to 1000 Kelvin. Induction system is used to heat up stainless steel cups containing the sample.

Accessory emissivity measurements are recorded under purged air by means of an external chamber attached to one of the Vertex80V spectrometers. A KBr and a CsI windows are used to close the spectrometer external port (allowing evacuation of the instrument) to measure in the 1 to 150 µm spectral range. The external chamber can be cooled down to 0° to minimize its influence on the measured radiation. Sample temperature can be set in the range 20°-150°C.
A Terra In-Xitu (http://www.olympus-ims.com/sv/xrf-xrd/mobile-benchtop-xrd/terra/) XRD system on loan from the ExoMars project is temporarily available for sample characterization.
The instruments are located in an air-conditioned room. The instruments and the accessory units used are fully automatized and the data calibration and reduction are made with homemade software.
 

Tools and sub-systems:

A number of sample preparation and analysis tools and experiment sub-systems are available to the facility:

For samples preparation: a collection of hundreds of rocks and minerals, synthetic minerals, an Apollo 16 lunar sample, several meteorites, set of sample holders for reflectance (plastic, aluminum or stainless steel), various sets of sieves, grinders, mortars, saw, balances, microscope, an oven (20° to 300°C), ultra-pure water, wet chemistry materials, a second ovens (30° to 3000°C) for sample treatments, a press to produce pellets (10mm or 20mm diameter), a large dry cabinet (moisture < 1%) for sample storage, 3 small exsiccators (moisture < 20%) for sample storage, a rotating device for producing intimate mixtures, purge gas generator for water and CO2 free air, liquid-nitrogen tank, an ultrasonic cleaning unit, 2 microscopes, air compressor pistol for cleaning.
 

Technical characteristics:

Spectral range:	0.2 - 150 µm (with high S/N, in vacuum, purged air or inert gas atmosphere)
Atmospheric pressure:	0.7 – 1000 mbar
Spectral resolution:	variable - mini: 0.1 cm-1 - maxi: 8 cm-1
Bidirectional Reflectance:	Incidence angle: 13° to 85° ; step 1° Emergence angle: 13° to 85° ; step 1° Sample holder diameter: 10 mm Sample holder depth: 1 to 2 mm
Emissivity:	Emergence angle: 0°, 5°, 10 to 60° ; step 10° Sample holder diameter: 50 mm Sample thickness: 1 to 3 mm (can be larger for slabs or solid samples, to 10mm) Sample weight: to fill a cup, depending on the grain size, 3 to 5 grams of material are needed Cup rim height: 0mm or 20mm or 50mm, depending on the experiment and the need to minimize thermal gradients in the samples heated in vacuum Picture: Reflectance and transmission unit Picture: Overview of the sample preparation
Samples:	Types: rocks, minerals, metals, ceramics, paints, blankets, optical filters or windows Texture: compact or granular Grain size: typical <25 µm, 25-63 µm, 63-125 µm, 125-250 µm + larger + slabs
Temperature:	room temperature or heated (emissivity)
Experiment control:	PC/Windows, fully software controlled. Automatic acquisition of all spectral/geometric configurations
Acquisition time:	Depending on the number of consecutive scans on the same target typical: 5 to 7 min for 500 scans in VIS and TIR under one geometrical configuration

 

Availability to community:

• Technical improvements/calibration (20%)
• DLR + associated laboratories measurements (60%)
• open as facility or to specific collaborations w. funding (20%)

 

This laboratory has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 871149.

To apply for time in this laboratory under the EuroPlanet Research Infrastructure please go to "TA2 Facility 5 – DLR Planetary Spectroscopy Laboratory – Europlanet Society".

References:

Maturilli A, Helbert J, Witzke A, Moroz L (2006) Emissivity measurements of analogue materials for the interpretation of data from PFS on Mars Express and MERTIS on Bepi-Colombo. PSS 54(11):1057-1064

Maturilli A, Helbert J, Moroz L (2008) The Berlin emissivity database (BED). PSS 56(3-4):420-425

Helbert J, Maturilli A (2009) The emissivity of a fine-grained labradorite sample at typical Mercury dayside temperatures. EPSL 285(3–4):347–354, DOI: 10.1016/j.epsl.2009.02.031.

Sprague AL, Donaldson Hanna KL, Kozlowski RWH, Helbert J, Maturilli A, Warell JB, Hora JL (2009) Spectral emissivity measurements of Mercury's surface indicate Mg- and Ca-rich mineralogy, K-spar, Na-rich plagioclase, rutile, with possible perovskite, and garnet. PSS 57(3):364-383

Helbert J, Hiesinger H, Walter I, Sauberlich T, Maturilli A, D'Amore M, Knollenberg J, Lorenz E, Peter G, Arnold G (2010) MERTIS: understanding Mercury's surface composition from mid-infrared spectroscopy. Proc. SPIE 7808, 78080J, DOI:10.1117/12.859816

Vernazza P, Carry B, Emery J, Hora JL, Cruikshank H, Binzel RP, Jackson J, Helbert J, Maturilli A (2010) Mid-infrared spectral variability for compositionally similar asteroids: Implications for asteroid particle size distributions. Icarus 207(2):800-809

Helbert J, Maturilli A, D’Amore M (2013a) Visible and near-infrared reflectance spectra of thermally processed synthetic sulfides as a potential analog for the hollow forming materials on Mercury. EPSL 369-370:233-238, doi:10.1016/j.epsl.2013.03.045

Helbert  J, Nestola F, Ferrari S, Maturilli A, et al. (2013b) Olivine thermal emissivity under extreme temperature ranges: Implication for Mercury surface. EPSL 371:252–257, doi: 10.1016/j.epsl.2013.03.038.

Maturilli A, Helbert J (2014) Characterization, testing, calibration, and validation of the Berlin emissivity database. Journal of Applied Remote Sensing. doi:10.1117/1.JRS.8.084985

Maturilli A, Helbert J, St. John JM, Head III JW, Vaughan WM, D’Amore M, Gottschalk M, Ferrari S (2014) Komatiites as Mercury surface analogues: Spectral measurements at PEL. EPSL 398:58-65. doi:10.1016/j.epsl.2014.04.035