Impact ionization mass spectra of anorthite cosmic dust analogue particles

Anorthite, the Ca-rich end-member of plagioclase feldspar, is a dominant mineral component of the Lunar highlands. Plagioclase feldspar is also found in comets, meteorites and stony asteroids. It is therefore expected to contribute to the population of interplanetary (and circumplanetary) dust grains within the solar system. After coating micron- and submicron-sized grains of Anorthite with a conductive layer of Platinum, the mineral was successfully accelerated to hypervelocity speeds in the Max Planck Institut für Kernphysik’s Van de Graaff accelerator. We present impact ionization mass spectra generated following the impacts of anorthite grains with a prototype mass spectrometer (the Large Area Mass Analyser, LAMA) designed for use in space, and discuss the behavior of the spectra with increasing impact energy. Correlation analysis is used to identify the compositions and sources of cations present in the spectra, enabling the identification of several molecular cations (e.g., CaAlO2, CaSiO2, Ca2AlO3/CaAlSi2O2) which identify anorthite as the progenitor bulk grain material

An on-line aerosol laser mass spectrometer with three, easily interchangeable laser based ionisation methods for characterisation of inorganic and aromatic compounds on particles.

An aerosol mass spectrometric set-up is presented comprising three different laser based techniques for on-line analysis of particles. The implemented methods are one-step laser desorption/ionisation (LDI), two-step laser desorption/photoionisation (LDPI) and thermal desorption/photoionisation (TDPI). Photoirmisation processes for the latter two methods are based on resonance enhanced multiphoton ionisation (REMPI), which is highly selective and sensitive for polyaromatic hydrocarbons (PAH). LDI is especially suitable for the detection of inorganic compounds and the determination of sum values such as elemental carbon content. Investigated samples were particles from spruce wood ash generated by an oxygen-controlled residential heating system and exhaust gases from a gasoline driven passenger car. In the positive LDI mass spectra several metal cations such as potassium and iron are detectable, whereas carbon clusters can be observed with the negative mode. With LD-REMPI and TD-REMPI various PAH such as phenanthrene and derivatives, pyrene, etc., become visible. In the wood ash samples relatively high yields of retene were found, which could be used as tracer compound for coniferous wood combustion. All three modes can be applied with only slight modifications of the instrument. Thus, it allows characterising single particles on a real time basis and, depending on the application, the most convenient technique can be selected

Bilan de fonctionnement 2014 des stations LSPIV en Ardèche

[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU [Relecteur_IRSTEA]Braud, I. ; Le Coz, J.Four stations were equipped with a permanent LSPIV data acquisition system we developed and installed, which consists of an analog video-camera driven by an industrial PC powered by Debian Linux with a dedicated application, the water level being measured with an external radar. This report explain the network and what happened in 2014.Bilan de fonctionnement 2014 des stations hydrométriques par analyse d'image en Ardèche