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Schwetzingen, Germany

Rodionov D.S.,Johannes Gutenberg University Mainz | Klingelhoefer G.,Johannes Gutenberg University Mainz | Evlanov E.N.,Russian Academy of Sciences | Blumers M.,Johannes Gutenberg University Mainz | And 8 more authors.
Solar System Research | Year: 2010

Möessbauer spectroscopy is a powerful tool for the mineralogical analysis of Fe-bearing materials. The miniaturized Möessbauer spectrometer MIMOS II has already been working on the surface of Mars for 6 years as part of the NASA Mars Exploration Rovers mission. The improved version of the instrument is a component of the scientific payload of the Phobos-Grunt mission. The scientific objectives of the instrument are the following: to identify the iron-bearing phases, to determine the quantitative distribution of iron among these phases, and to determine the distribution of iron among its oxidation states. © 2010 Pleiades Publishing, Ltd.

Auer S.,A&M Associates | Lawrence G.,University of Colorado at Boulder | Grn E.,University of Colorado at Boulder | Grn E.,Max Planck Institute for Nuclear Physics | And 6 more authors.
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2010

A self-triggered dust trajectory sensor not only determines the trajectories of charged dust particles but also acts as a highly sensitive dust detector. The objective of a dust trajectory sensor (DTS) is to measure charges Q<100 aC and trajectories of submicron-sized grains with accuracies of ∼1° in direction and ∼1% in speed in the range v=1100 km/s. It determines the trajectories from the signals induced in an array of wire electrodes. Most signals are weak and distorted by amplifier noise. Transient recorders continuously store them until a trigger signal indicates the presence of a dust particle. A trigger signal was previously available only after the particle had passed through the DTS and was detected externally by impact ionization. In certain important applications, however, an external trigger is not available or too late. In this paper we discuss a method of generating a trigger from noisy DTS signals before the dust grain exits the sensor. Specifically, we use seven parallel, double-triangle-shaped velocity filters on each sensor electrode to cover the velocity range v=1128 km/s. Each velocity filter feeds into four parallel amplitude filters, two for single large signals and two for pairs of smaller but coincident signals from adjacent wires. We demonstrate by computer simulation that the probability of generating at least one trigger is high, typically pt<0.99 at v=20 km/s, charge-to-noise ratio QNR<6.25, and angle of incidence from 0° to 27°. The minimum QNR required to derive a trigger varies with dust velocity as ∼v1/2. The false event rate, caused by amplifier noise, is estimated to be on the order of one per year. © 2010 Elsevier B.V.

Reisert S.,FH Aachen | Henkel H.,Von Hoerner and Sulger GmbH | Schneider A.,Von Hoerner and Sulger GmbH | Schafer D.,Aseptiksysteme and Foodtechnology | And 3 more authors.
Physica Status Solidi (A) Applications and Materials Science | Year: 2010

A handheld sensor system for the online measurement of hydrogen peroxide (H2O2) in aseptic sterilisation processes has been developed. It is based on a calorimetric-type gas sensor that consists of a differential set-up of two temperature sensors, of which one is catalytically activated and the second one is passivated and used as reference. The sensor principle relies in detecting a rise in temperature on the active sensor due to the exothermic reaction of H2O2 on the catalytic surface. To characterise the sensor system towards H2O2 sensitivity and other influencing factors, measurements have been carried out both at an experimental set-up and a manufacturer's sterilisation machine. Physical sensor characterisation was done by means of the optical microscopy. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kirchner P.,FH Aachen | Kirchner P.,Julich Research Center | Ng Y.A.,FH Aachen | Spelthahn H.,FH Aachen | And 9 more authors.
Physica Status Solidi (A) Applications and Materials Science | Year: 2010

In aseptic filling systems, hydrogen peroxide vapour is commonly used for the reduction of microbial contaminations in carton packages. In this process, the germicidal efficiency of the vapour depends especially on the H 2O2 concentration. To monitor the H2O 2 concentration,acalorimetric H2O2 gas sensor based on a catalytically activated thin-film thermopile is investigated. Two different sensor layouts, namely a circular and a linear form, as well as two various material pairs such as tungsten/nickel and gold/nickel, have been examined for the realization of a thin-film thermopile. Additionally, manganese oxide and palladium particles have been compared as responsive catalysts towards H2O2. The thin-film sensors have been investigated at various H2O2 concentrations, gas temperatures and flow rates. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pavlov S.G.,German Aerospace Center | Jessberger E.K.,University of Munster | Hubers H.-W.,German Aerospace Center | Hubers H.-W.,TU Berlin | And 6 more authors.
Advances in Space Research | Year: 2011

Jupiter's icy moon Europa is one of most promising places in our Solar System where possible extraterrestrial life forms could exist either in the past or even presently. The Europa Lander mission, an exciting part of the international Europa Jupiter System Mission (EJSM/Laplace), considers in situ planetary exploration of the moon. The distance of Europa from the Earth and the Sun asks for autonomous analytical tools that maximize the scientific return at minimal resources, demanding new experimental concepts. We propose a novel instrument, based on the atomic spectroscopy of laser generated plasmas for the elemental analysis of Europa's surface materials as far as it is in reach of the lander for example by a robotic arm or a mole, or just onboard the lander. The technique of laser-induced plasma spectrometry provides quantitative elemental analysis of all major and many trace elements. It is a fast technique, i.e. an analysis can be performed in a few seconds, which can be applied to many different types of material such as ice, dust or rocks and it does not require any sample preparation. The sensitivity is in the range of tens of ppm and high lateral resolution, down to 50 μm, is feasible. In addition, it provides the potential of depth profiling, up to 2 mm in rock material and up to a few cm in more transparent icy matrices. Key components of the instrument are presently developed in Germany for planetary in situ missions. This development program is accompanied by an in-depth methodical investigation of this technique under planetary environmental conditions. © 2010 COSPAR. Published by Elsevier Ltd. All rights reserved.

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