Schwetzingen, Germany
Schwetzingen, Germany

Time filter

Source Type

Kirchner P.,FH Aachen | Kirchner P.,Jülich 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.


Kirchner P.,FH Aachen | Kirchner P.,Jülich Research Center | Li B.,FH Aachen | Spelthahn H.,FH Aachen | And 7 more authors.
Sensors and Actuators, B: Chemical | Year: 2011

In common aseptic filling processes, hydrogen peroxide vapour is a predominantly applied antimicrobial for the inactivation of microorganisms in packages. During this process, the germicidal effectivity of the antimicrobial treatment depends especially on the H2O2 concentration of the gas mixture. For the detection of H2O2 in aseptic filling processes, a novel thin-film calorimetric gas sensor based on a differential set-up of a catalytically activated and a passivated temperature sensing element has been realised in the present work. The sensor device contains two meander-shaped platinum resistances as temperature sensing elements; both have been passivated with spin-coated perfluoralkoxy. As catalytically active materials for the calorimetric gas sensor, palladium, platinum black and manganese oxide particles have been studied in the developed experimental set-up, wherein MnO2 has shown the highest sensitivity of 0.57 °C/% (v/v) towards H2O2. Afterwards, the characteristic of the sensor device with MnO2 particles as catalyst has been examined at various H2O2 concentrations and additionally, the influence of gas temperature and gas flow rate on the sensor signal has been validated in the experimental set-up. © 2010 Elsevier B.V. All rights reserved.


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.


Falke P.,German Aerospace Center | Fischer H.-H.,German Aerospace Center | Seidensticker K.J.,German Aerospace Center | Thiel K.,University of Cologne | And 4 more authors.
Acta Astronautica | Year: 2016

On its more than 10. years journey to comet 67P/Churyumov-Gerasimenko, Rosetta carried RadFET ionising dose monitors in the central electronics of the orbiter instrument COSIMA and the lander instrument SESAME. The readings of the dosimeters were corrected for the temperature of the devices during measurements. Because the sensitivity of RadFETs depends on the energy of impinging charged particles, a mean efficiency factor for the prevalent proton radiation was determined by applying nine efficiency models to proton energy spectra of Rosetta's radiation environment.The resulting dose profiles show linear increases of the accumulated dose with time, mainly caused by galactic cosmic radiation, and the arrival of two solar particle events in 2005. The accumulated dose (in Silicon) during 3909 days in space from 2004-03-02 to 2014-11-14 was 3.2±0.6Gy in case of COSIMA and 1.9±0.4Gy for SESAME. The deviation of the two measurements is mainly due to the solar particle event in September 2005, which had a 5.3±1.0 times stronger impact on the COSIMA RadFET. Measured dose levels are one order of magnitude lower than those expected before launch for not being exceeded on the 90% confidence level, which is mainly due to the low solar activity during the mission so far. © 2016 IAA.


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.


Haarmann R.,Kayser Threde GmbH | Jaumann R.,German Aerospace Center | Claasen F.,German Aerospace Center | Apfelbeck M.,German Aerospace Center | And 5 more authors.
Planetary and Space Science | Year: 2012

In late 2010, the DLR Space Administration invited the German industry to submit a proposal for a study about a Mobile Payload Element (MPE), which could be a German national contribution to the ESA Lunar Lander Mission. Several spots in the south polar region of the moon come into consideration as landing site for this mission. All possible spots provide sustained periods of solar illumination, interrupted by darkness periods of several 10 h. The MPE is outlined to be a small, autonomous, innovative vehicle in the 10 kg class for scouting and sampling the environment in the vicinity of the lunar landing site. The novel capabilities of the MPE will be to acquire samples of lunar regolith from surface, subsurface as well as shadowed locations, define their geological context and bring them back to the lander. This will enable access to samples that are not contaminated by the lander descent propulsion system plumes to increase the chances of detecting any indigenous lunar volatiles contained within the samples. Kayser-Threde, as prime industrial contractor for Phase 0/A, has assembled for this study a team of German partners with relevant industrial and institutional competence in space robotics and lunar science. The primary scientific objective of the MPE is to acquire clearly documented samples and to bring them to the lander for analysis with the onboard Lunar Dust Analysis Package (L-DAP) and Lunar Volatile Resources Analysis Package (L-VRAP). Due to the unstable nature of volatiles, which are of particular scientific interest, the MPE design needs to provide a safe storage and transportation of the samples to the lander. The proposed MPE rover concept has a four-wheeled chassis configuration with active suspension, being a compromise between innovation and mass efficiency. The suspension chosen allows a compact stowage of the MPE on the lander as well as precise alignment of the solar generators and instruments. Since therefore no further complex mechanics are necessary, the active suspension significantly contributes to the lightweight MPE design. The thermal control system enables the MPE to operate in shaded areas for about 2 h and hibernate darkness periods of about 14 h. Increasing the hibernation capability requires additional battery capacity and thus increases the MPE mass. As operational modes teleoperations from earth and autonomous navigation are foreseen. The MPE payload includes navigation cameras, a close-up imager and a mole as sampling device. The MPE phase 0/A study finished in early 2012. This article describes the resulting MPE rover concept with focus on its scientific benefit for the Lunar Lander Mission. © 2012 Elsevier Ltd. All rights reserved.


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.


Klingelhofer G.,Johannes Gutenberg University Mainz | Girones Lopez J.,Johannes Gutenberg University Mainz | Bruckner J.,Max Planck Institute for Chemistry | D'Uston C.,Roche Holding AG | And 4 more authors.
IEEE Nuclear Science Symposium Conference Record | Year: 2012

Both Alpha Particle X-ray Spectrometer (APXS) and the Miniaturized Moessbauer Spectrometer (MIMOS II) have shown their performances in space missions and terrestrial applications. Taking advantage of the challenges of space missions both instruments have become very powerful tools, even small in mass and dimensions. © 2011 IEEE.


Schroder C.,Johannes Gutenberg University Mainz | Schroder C.,University of Tübingen | Klingelhofer G.,Johannes Gutenberg University Mainz | Morris R.V.,NASA | And 8 more authors.
Geochemistry: Exploration, Environment, Analysis | Year: 2011

Iron occurs naturally as Fe2+, Fe3+, and, to a lesser extent, as Fe0. Many fundamental (bio)geochemical processes are based on redox cycling between these oxidation states. Mössbauer spectroscopy provides quantitative information about the distribution of Fe among its oxidation states, identification of Fe-bearing phases, and relative distribution of Fe among those phases. Portable, miniaturized Mössbauer spectrometers were developed for NASA's Mars Exploration Rovers (in operation since 2004) and provide a means for non-destructive, in-situ field investigations. On Mars, these instruments provided evidence for aqueous activity with implications for habitability, were applied in geological mapping of the landing sites, and helped to identify meteorites, for example. On Earth, they were used in field studies of green rust, the identification of air pollution sources, or the study of archaeological artefacts. Their application to in-situ resource utilisation (ISRU) on the Moon has been demonstrated in a recent NASA field test of hardware for oxygen production. A new detector system in an advanced version of these instruments is based on Si Drift Detectors and permits the simultaneous acquisition of X-ray fluorescence spectra to determine elemental compositions. © 2011 AAG/Geological Society of London.


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.

Loading Von Hoerner and Sulger GmbH collaborators
Loading Von Hoerner and Sulger GmbH collaborators