• Fast pulsed operation of a small non-radioactive electron source with continuous emission current control 

  Cochems, Philipp; Kirk, Ansgar T.; Bunert, Erik; Runge, M.; Goncalves, P.; Zimmermann, Stefan (College Park, MA : American Institute of Physics (AIP), 2015)

  Non-radioactive electron sources are of great interest in any application requiring the emission of electrons at atmospheric pressure, as they offer better control over emission parameters than radioactive electron sources ...
• A compact high-resolution X-ray ion mobility spectrometer 

  Reinecke, Tobias; Kirk, Ansgar T.; Heptner, Andre; Niebuhr, D.; Böttger, S.; Zimmermann, Stefan (College Park, MA : American Institute of Physics (AIP), 2016)

  For the ionization of gaseous samples, most ion mobility spectrometers employ radioactive ionization sources, e.g., containing 63Ni or 3H. Besides legal restrictions, radioactive materials have the disadvantage of a constant ...
• Shutterless ion mobility spectrometer with fast pulsed electron source 

  Bunert, Erik; Heptner, Andre; Reinecke, T.; Kirk, Ansgar T.; Zimmermann, Stefan (College Park, MA : American Institute of Physics (AIP), 2017)

  Ion mobility spectrometers (IMS) are devices for fast and very sensitive trace gas analysis. The measuring principle is based on an initial ionization process of the target analyte. Most IMS employ radioactive electron ...
• A sensitive gas chromatography detector based on atmospheric pressure chemical ionization by a dielectric barrier discharge 

  Kirk, Ansgar T.; Last, Torben; Zimmermann, Stefan (Amsterdam : Elsevier, 2017)

  In this work, we present a novel concept for a gas chromatography detector utilizing an atmospheric pressure chemical ionization which is initialized by a dielectric barrier discharge. In general, such a detector can be ...
• Ion mobility spectrometer with orthogonal X-Ray source for increased sensitivity 

  Bunert, Erik; Reinecke, Tobias; Kirk, Ansgar T.; Bohnhorst, Alexander; Zimmermann, Stefan (Amsterdam : Elsevier, 2018)

  Ion mobility spectrometers (IMS) are compact devices for extremely sensitive detection of proton and electron affine volatile compounds down to low pptv concentrations within less than a second. The measuring principle ...
• A simple centripetal force model for explaining the focusing effect of ion funnels 

  Allers, Maria; Kirk, Ansgar T.; Zimmermann, Stefan (Amsterdam : Elsevier, 2018)

  The ion funnel is one of the key components for transferring ions from higher pressure into vacuum. While known for over twenty years and thoroughly analyzed by mathematical means and simulations, its working principle ...
• Pulsed electron source for atmospheric pressure chemical ionization in ion mobility spectrometry 

  Bunert, Erik; Heptner, Andre; Kirk, Ansgar T.; Käbein, Oliver; Zimmermann, Stefan; Kusch, Alexander; Wurz, Marc Christopher (Piscataway, NJ : IEEE, 2017)

  Ion mobility spectrometers (IMS) are measurement devices for fast and ultra-sensitive trace gas analysis. Most IMS employ radioactive electron sources, such as 3 H or 63 Ni, to provide free electrons with high kinetic ...
• Ionenmobilitätsspektrometrie 

  Kirk, Ansgar T.; Zimmermann, Stefan (Weinheim : Wiley, 2016)

  Ionenmobilitätsspektrometer sind extrem schnelle und sensitive Sensoren für Spurengase, welche diese anhand ihrer Bewegung durch ein Neutralgas unter dem Einfluss eines elektrischen Feldes identifizieren. In diesem Artikel ...
• In-circuit-measurement of parasitic elements in high gain high bandwidth low noise transimpedance amplifiers 

  Cochems, Philipp; Kirk, Ansgar T.; Zimmermann, Stefan (College Park, MA : American Institute of Physics (AIP), 2014)

  Parasitic elements play an important role in the development of every high performance circuit. In the case of high gain, high bandwidth transimpedance amplifiers, the most important parasitic elements are parasitic ...
• Bradbury-Nielsen vs. Field switching shutters for high resolution drift tube ion mobility spectrometers 

  Kirk, Ansgar T.; Zimmermann, Stefan (Berlin, Heidelberg : Springer, 2014)

  A key component in the design of every drift tube ion mobility spectrometer (IMS) is the ion shutter which controls the injection of ions into the drift tube. Especially, compact drift tube IMS require very short injection ...
• Pushing a compact 15 cm long ultra-high resolution drift tube ion mobility spectrometer with R = 250 to R = 425 using peak deconvolution 

  Kirk, Ansgar T.; Zimmermann, Stefan (Berlin, Heidelberg : Springer, 2015)

  Recently, we have published an analytical model describing the resolution and signal-to-noise-ratio of peaks present in an ion mobility spectrum acquired by a drift tube instrument. Based on this model, we designed a ...
• An analytical model for the optimum drift voltage of drift tube ion mobility spectrometers with respect to resolving power and detection limits 

  Kirk, Ansgar T.; Zimmermann, Stefan (Berlin, Heidelberg : Springer, 2015)

  One of the key experimental parameters of measurements using a drift tube ion mobility spectrometer is the drift voltage applied across its length, as it governs a multitude of processes during the ion drift. While the ...
• Transient simulation of moving ion clouds in time-of-flight ion mobility spectrometers operating with DC and AC fields 

  Allers, M.; Bohnhorst, A.; Kirk, Ansgar T.; Ungethüm, B.; Walte, A.; Zimmermann, S. (Berlin, Heidelberg : Springer, 2015)

  Ion mobility spectrometers can be divided by their principle of ion separation. For example, classical drift tube time-of-flight Ion Mobility Spectrometers (IMS) separate ions by the absolute value of their low field ion ...
• Simulation aided design of a low cost ion mobility spectrometer based on printed circuit boards 

  Bohnhorst, A.; Kirk, Ansgar T.; Zimmermann, S. (Berlin, Heidelberg : Springer, 2016)

  Miniaturized low-cost drift tubes with high analytical performance are a key component for the design of powerful and mass-deployable hand-held ion mobility spectrometers. Thus, a simple model that estimates the influence ...
• A universal relationship between optimum drift voltage and resolving power 

  Kirk, Ansgar T.; Bakes, Kai; Zimmermann, Stefan (Berlin, Heidelberg : Springer, 2017)

  The drift voltage is one of the key experimental parameters of any drift tube ion mobility spectrometer. In this work, we show that a universal relationship between optimum drift voltage and the resolving power reached at ...
• Acetone and perdeuterated acetone in UV-IMS 

  Raddatz, Christian-Robert; Allers, Maria; Kirk, Ansgar T.; Zimmermann, Stefan (Berlin, Heidelberg : Springer, 2018)

  Measuring a mixture of acetone and perdeuterated acetone (acetone-d6) with an ultra-high resolution drift time ion mobility spectrometer (resolving power of Rp = 235) and ultraviolet ionization (10.6 eV) at ambient pressure ...
• A Simple Analytical Model for Predicting the Detectable Ion Current in Ion Mobility Spectrometry Using Corona Discharge Ionization Sources 

  Kirk, Ansgar T.; Kobelt, Tim; Spehlbrink, Hauke; Zimmermann, Stefan (Cham : Springer Nature Switzerland AG, 2018)

  Corona discharge ionization sources are often used in ion mobility spectrometers (IMS) when a non-radioactive ion source with high ion currents is required. Typically, the corona discharge is followed by a reaction region ...
• Coupling of a High-Resolution Ambient Pressure Drift Tube Ion Mobility Spectrometer to a Commercial Time-of-flight Mass Spectrometer 

  Allers, Maria; Timoumi, Laila; Schlottmann, Florian; Zimmermann, Stefan (Cham : Springer Nature Switzerland AG, 2018)

  Ion mobility spectrometry provides information about molecular structures of ions. Hence, high resolving power allows separation of isomers which is of major interest in several applications. In this work, we couple our ...
• Analyzing and improving diversification, privacy, and information management on the web 

  Djafari Naini, Kaweh (Hannover : Institutionelles Repositorium der Leibniz Universität Hannover, 2019)

  Today, the World Wide Web has become the main source and medium for people to access, share, and manage information. Since user expectations towards all three types of functionalities are high and information volumes are ...
• Properties and structure of magnetic alkali-borosilicate glasses prepared by induction melting 

  Naberezhnov, A.; Nacke, B.; Nikanorov, A.; Koroleva, E.; Vanina, P.; Alekseeva, O.; Tomkovich, M.; Andreeva, N. (Bristol : Institute of Physics Publishing, 2018)

  In this contribution we present the first results devoted to studies of structure, morphology and magnetic properties of magnetic alkali-borosilicate glasses prepared by induction melting. This procedure permits to fabricate ...

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