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A key differentiator in customer satisfaction in the automotive industry is offering a choice of high-dimensional possibilities to customize an individual vehicle. In the luxury segment this equals more than one billion variants. Innovative data-driven processes are necessary for the planning and handling of vehicles in production and distribution in order to guarantee indispensable factors such as stability, flexibility and transparency across the entire supply chain and to deliver the right vehicle to the right place at the promised time. Highly complex business environments, multi-variant products, trends with effects on distribution networks and future mobility concepts confront manufacturers with new challenges. This paper provides a survey of currently used methods and technologies to handle the previously mentioned challenges in the area of the customer order management of an automotive manufacturer. A specific field of research is the concept of planned orders which are derived from early anticipated customer requirements and their utilization throughout the entire planning and order management process. In addition to the generic approaches for achieving integrated planning of sales and production programs as well as the resulting material requirements, artificial intelligence methods are investigated with regard to the concept of the planned orders. For this purpose, various existing approaches to anticipate planned orders and to effectively manage the supply chain are examined. In conclusion, this paper provides a survey of state of the art methods regarding artificial intelligence linked to current research on agile production systems. Despite existing uncertainty in the upcoming years the implementation of stable data-driven processes is crucial. In this context, the possibility to prepare an automotive manufacturer for the upcoming challenges in digitalization and globalization is evaluated.

Im Dezember 2013 verunfallte ein Rettungstransportwagen (RTW) bei einer Einsatzfahrt. Die transportierte Patientin verstarb. Anlasslich der Gerichtsverhandlung wurden im Rahmen der Beweisaufnahme Rechtsvorschriften und gangige Praxis der Anschnallpflicht erortert. Der 27-jahrige Fahrer wurde zu einer Geldstrafe verurteilt. Die gesetzlichen Vorgaben zur Anschnallpflicht, Sonderrechten und Wegerecht sind in der Strasenverkehrsordnung (StVO) festgelegt. Anhand des Fallbeispiels werden Moglichkeiten und Grenzen der medizinischen Versorgung wahrend eines Notfalltransports diskutiert.

Amorphous hydrogenated carbon (a-C:H) deposited on steel with plasma enhanced chemical vapor deposition can be used as elongation tolerant oxygen barrier. However, the elongation tolerance of the a-C:H film is lost if deposited on a poly(ethylene terephthalate) (PET) for reasons unknown. To assess this phenomenon, a-C:H was deposited on PET, silicon substrates, and silicon micro-cantilevers, and the stress was determined by measuring the radius of curvature. a-C:H deposited on PET showed lower compressive stress than on silicon. This difference is not due to the formation of a gradient layer or plastic deformation of PET. Instead, the most probable explanation is that energetic ions cause a partial release of biaxial orientation within the PET, thereby reducing the compressive stress.

Atomic layer deposition (ALD) is increasingly becoming commonplace to deposit high density, conformal films, as novel deposition techniques allow improved deposition rates on various substrates. Diffusion and miscibility of ALD precursors with polymers are known to affect film nucleation. To assess the influence of polymeric underlayer on the growth and mechanical behavior of ALD films, we deposited aluminum oxide (Al2O3) and titanium dioxide (TiO2) films on three different polymers with known reactivity to the ALD precursors and compared them to films on polyethylene terephthalate (PET). We present the trends in nucleation and penetration of the ALD films on the various polymers as well as the in situ mechanical behavior under tensile strain. X-ray photoelectron spectroscopy (XPS) revealed that Cytop, a fluorinated polymer and polyethyleneimine ethoxylated (PEIE) delay the nucleation of Al2O3 and TiO2 films. Time-of-flight mass spectrometry (ToFSIMS) shows the extent of diffusion of the ALD precursors into the polymer underlayer, delaying nucleation. Tensile tests show that while the crack onset strain remained unchanged despite the various polymer underlayers, the crack saturation density decreased for ALD films on PEIE and polyhydroxystyrene (PHOST). Films on Cytop showed no crack saturation limit until the nucleation delay was overcome indicating that judicious choice of the ALD film and polymer underlayer will allow tailoring of the length of the diffusion zone and crack saturation, but not the crack onset strain, which will be addressed in future studies.

Barrier performance and crack formation of amorphous silicon a-Si(O, H)/diamond-like carbon (a-C:H) bilayer thin films were studied under uniaxial stretch forming. The plasma polymer films were prepared on bare and PET film coated stainless steel substrates to enable the investigation of the influence of different substrate mechanics on the crack formation. In-situ electrochemical impedance spectroscopy (EIS) results indicated that film thickness reduction and onset of crack formation depend on the substrate mechanics. The reduced residual compressive internal stresses on the PET coated metal substrate caused film failure as early as at 3% strain. On the contrary, for the bare metal substrate, first cracks were observed at 8% strain, typically at defect sites. Moreover, it was demonstrated that for such a bilayer film system, individual layers can fail independently, indicating the importance of local stress fields.

The adhesion of thin CVD films on polyolefins is often critical due to the low surface free energy of the polymers. In this study, injection moulded PP samples are produced and investigated. The samples are treated in very well-characterized pulsed plasmas before a HMDSO-based coating is applied. The resulting bond strength is analyzed using pull-off tests. The fractured interfaces are characterized with XPS. Oxygen and argon plasma pre-treatments of the PP samples result in a bond strength improvement by a factor of about 2. Comparing oxygen and argon pre-treatments at equal ion fluences to the surface, it can be shown that the bond strength between CVD-coating and polymer is similar.

The carbon conversion in a N2-CH4 radiofrequency (RF) discharge is investigated by analyzing both the gas phase and the dust produced. HCN is identified as the main reactive product and both HCN and NH3 are quantified. This quantification allows determining the carbon conversion yield from CH4 to HCN, which appears to be surprisingly low. The comparison of the infrared absorbance spectra between dust produced in two similar RF plasma setups emphasizes small differences on the CH3/CH2 bonds ratio in the samples. This difference is explained by the aging processes of dust within the plasma.

Metastable states play an important role in many plasmas because they are often one of the main ionization channels and therefore essential for the discharge dynamics. Because of their high population, density fluxes of metastable states on surfaces are not negligible compared to fluxes of reactive species or ions. If the energy of argon metastable states (Arm) is high enough to cause bond breakage or other surface reactions, they can be an alternative component to treat substrates. In view of the role of Arm in an inductively coupled PECVD reactor for the deposition of barrier films on PET, the densities, lifetimes, and fluxes of Arm are quantified by means of tuneable diode laser absorption (TDLAS) and compared to the ion flux.

In this paper, we present the results of mechanical testing that reveals the onset crack strain and fatigue crack growth of TiO2 and Al2O3 films deposited by atomic layer deposition. Data show that both films have a strong thickness dependence of the onset crack strain, with the strain reducing with increasing film thickness. Additionally, TiO2 films have a lower onset crack strain and strain for fatigue damage than Al2O3. However, TiO2 films are more resilient in harsh environments where fatigue damage in Al2O3 films grows faster.

The growth of tungsten oxide (WO3) based thin films was achieved via metalorganic chemical vapor deposition using an all-nitrogen coordinated tungsten precursor in combination with oxygen. Film growth was performed on Si(100) substrates in the temperature range of 400–800 °C. Employing multi-technique approaches like X-ray diffraction, scanning electron microscopy, atomic force microscopy, Rutherford back scattering, nuclear reaction analysis and X-ray photoelectron spectroscopy, the variation of the growth characteristics and film properties with deposition temperature were studied in terms of crystallinity, structure, surface roughness and composition. Special attention was devoted to the investigation of variations in the film composition for the as-deposited and annealed films.

article i nfo Argon ions were implanted in metallic, semiconducting or insulating substrates, and investigated with X-ray photoelectron spectroscopy. Analysis of the Ar2p core level of argon showed clear differences in binding energy position and width as function of the matrix material, implantation energy, and post-annealing treatment. Although argon is not expected to form chemical bonds with the host matrix, the electronic shells within the gas atom can react to their environment according to different effects. It is shown that the precise determination and correct interpretation of the binding energy levels of the embedded gas atoms provides information about the local environment of the matrix such as amorphization of the crystalline structure, defect healing or gas bubble formation.

In2O3 thin films were grown by atomic vapor deposition (AVD) on Si(100) and glass substrates from a tris-guanidinate complex of indium [In(N(i)Pr2guanid)3] under an oxygen atmosphere. The effects of the growth temperature on the structure, morphology and composition of In2O3 films were investigated. X-ray diffraction (XRD) measurements revealed that In2O3 films deposited in the temperature range 450-700 degreesC crystallised in the cubic phase. The film morphology, studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM), was strongly dependent on the substrate temperature. Stoichiometric In2O3 films were formed under optimised processing conditions as was confirmed by X-ray photoelectron and X-ray excited Auger electron spectroscopies (XPS, XE-AES), as well as by Rutherford backscattering spectrometry (RBS). Finally, optical properties were investigated by photoluminescence (PL) measurements, spectroscopic ellipsometry (SE) and optical absorption. In2O3 films grown on glass exhibited excellent transparency (approximately 90%) in the Visible (Vis) spectral region.

Metal−organic chemical vapor deposition (MOCVD) of thin films of two representative rare-earth nitrides is reported here for the first time. Four homoleptic, all-nitrogen-coordinated, rare-earth (RE) complexes were evaluated as precursors for the respective nitride thin film materials. Two guanidinato complexes [RE{(iPrN)2C(NMe2)}3] [RE = Gd (1), Dy (2)] and two amidinato complexes [RE{(iPrN)2CMe}3] [RE = Gd (3), Dy (4)] were compared and used either as single source precursors or together with ammonia for MOCVD of gadolinium nitride (GdN) and dysprosium nitride (DyN), respectively. The thermal properties of the precursors were studied and the fragmentation patterns were characterized by high-resolution electron impact−mass spectrometry (HR EI-MS). The obtained nitride films were investigated using a series of techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), nuclear reaction analysis (NRA), Rutherford backscattering (RBS), and X-ray photoelectron spectroscopy (XPS). The f...

The progressive liquid-phase layer-by-layer (LbL) growth of anisotropic multicomponent layer-based porous coordination polymers (PCPs) of the general formula [M(L)(P)(0.5)] (M: Cu(2+), Zn(2+); L: dicarboxylate linker; P: dinitrogen pillar ligand) was investigated by using either pyridyl- or carboxyl-terminated self-assembled monolayers (SAMs) on gold substrates as templates. It was found that the deposition of smooth, highly crystalline, and oriented multilayer films of these PCPs depends on the conditions at the early growth cycles. In the case of a two-step process with an equimolar mixture of L and P, growth along the [001] direction is strongly preferred. However, employing a three-step scheme with full separation of all components allows deposition along the [100] direction on carboxyl-terminated SAMs. Interestingly, the growth of additional layers on top of previously grown oriented seeding layers proved to be insensitive to the particular growth scheme and full retention of the initial orientation, either along the [001] or [100] direction, was observed. This homo- and heteroepitaxial LbL growth allows full control over the orientation and the layer sequence, including introduction of functionalized linkers and pillars.

The resistance against cavitation erosion of hydrogenated a-C:H coated materials coated by PECVD process has been evaluated. Coatings of thicknesses between 50 and 300 nm were deposited on a pseudoelastic NiTi and two stainless steel substrates and were tested by vibratory cavitation. The results show that the incubation periods of the tested coatings deposited on steel substrates were differently modified as the coating thickness was increased depending on the type of steel substrate. On the other hand, a-C:H coatings below a critical thickness deposited on pseudoelastic NiTi exhibit an excellent resistance against cavitation erosion. The outstanding results observed in a-C:H coatings deposited on NiTi are attributed to the coating capability of copying the reversible deformation that takes place in the metallic substrate combined with a strong adhesive connection. Based on the above results, a promising application potential of a-C:H on pseudoelastic shape memory substrates is expected.

Space resolved concentrations of helium He* (3S1) and argon Ar* (3P2) metastable atoms in an atmospheric pressure radio frequency micro-plasma jet were measured using tunable diode laser absorption spectroscopy. Even small absorptions down to 10-4 could be measured using lock-in technique. The absolute density of metastable atoms densities at different rf-power, flow rate and gas mixture was deduced from measured absorption rates. Metastable concentrations range from 109 to 1011 cm-3. Analysis of spectral profiles provided the pressure broadening coefficients of both metastable atoms by helium. The spatial distribution of metastable atoms in the plasma volume was obtained for various discharge conditions. Density profiles between the electrodes reveal the sheath structure and reflect the plasma excitation distributions in the discharge volume. It reveals the dominance of the α-mode discharge.

A bilayer system consisting of amorphous hydrogenated carbon with an amorphous silicon interlayer has been developed to coat shape memory alloys made of nickel and titanium (NiTi) with an elastic wear resistant film. The plasma deposited film system exhibits excellent adhesion on NiTi. Tensile tests reveal high elasticity of the film system, in that it can be elongated up to 4.5% before the occurrence of fine cracks. The film system shows hardness values from 5 to 20 GPa, depending on deposition conditions. In micro scratch tests a high critical load is reached.

1. General The plasma absorption probe (PAP) is a recently developed tool for the efficient determination of electron densities, especially in reactive plasmas. A dielectric cover protects this probe against the influences in reactive plasmas and it withstands conditions where Langmuir probes are easily damageable. The detection principle of the probe is based on active resonance spectroscopy. Active resonance spectroscopy is a method applied by many precedent researchers and used at present in diverse applications. The lack of adequate calibration constants and the occurrence of multiple absorption signals were two major drawbacks of the PAP, which are successfully overcome in this work. Design variations are tested by numerical computation and the model-based achievements are established in experiment. This redesigned PAP is optimized for the easy determination of electron densities. This tool works fast and efficiently, in particular in discharges in reactive gases.

We have utilised in situ Rayleigh-Mie scattering ellipsometry to analyse the growth process of amorphous hydrogenated carbon nitride (a-C:H:N) nanoparticles synthesised in a plasma of nitrogen and acetylene. The validity of the measurements is shortly discussed. The complex refractive indices in dependence of the particle radius are carefully determined and compared with a-C:H(:N) films which are deposited under similar conditions and analysed via multiple wavelength ellipsometry. Internal structures of the nanoparticles are then deduced from the change of optical constants during the growth.

The plasma absorption probe has been developed to provide a fast and efficient diagnostic tool for the characterisation of discharges, especially of reactive plasmas. Unlike Langmuir probes, the plasma absorption probe measures electron densities in reactive plasmas undisturbed by coatings of the probe surface. It consists of a semirigid coaxial cable with protruding inner conductor as an antenna, covered by a dielectric tube. The measurement principle is based on active resonance spectroscopy. A network analyser feeds the coaxial cable with HF of variable frequency and the power reflection spectrum is detected. At resonant frequencies, characteristic for the discharge, absorption signals are observed. In this paper, we present measurements of the plasma absorption probe for various discharge conditions and we evaluate the probes' further potential for the analysis of reactive plasmas.

Thin film properties such as homogeneity (radial profiles), optical constants, carbon density in the film, and the surface structures are strongly dependent on deposition conditions. We have investigated a-C:H/a-C:H(N) thin film deposition by expanding Ar-CH4 and Ar/N2-CH4 surface wave sustained plasmas at a frequency of 2.45 GHz. The influence of the plasma parameters such as pressure, input power, gas mixture rate, and an external bias voltage on the change of the film properties is systematically studied. An external bias applied to the substrate leads to more dense and harder a-C:H films, i.e. change from soft polymer-like to hard diamond-like. Rutherford backscattering and atomic force microscope surface topology confirm the densification of the films.

In this paper, we analyse the morphology and chemistry of carbonaceous dust particles previously proposed as a candidate analogue material for dust in the diffuse interstellar medium (ISM). The particles were polymerized in a low pressure capacitively coupled radiofrequency discharge in mixtures of argon/acetylene and helium/acetylene. Infrared (IR) spectra of our dust particles reveal the strong presence of aliphatic features, both stretching and bending modes, which are very similar to astronomical data from diffuse interstellar dust. A comparison between the IR spectra obtained using argon or helium as buffer gases reveals the strong presence of C = C double bonds (skeletal modes) when helium is used. The presence of these skeletal modes is clearly visible through the broad absorption feature at 1600 cm−1 (6.25 µm). The origin of this feature in our laboratory analogue is related to the change in the plasma parameters due to the variation of the buffer gas used under the same discharge conditions. Observational data of interstellar polycyclic aromatic hydrocarbons also exhibit a feature at this wavelength.

Small particles with sizes between a few nanometers and a few 10 µm (dust) are formed in fusion devices by plasma–surface interaction processes. Though it is not a major problem today, dust is considered a problem that could arise in future long pulse fusion devices. This is primarily due to its radioactivity and due to its very high chemical reactivity. Dust formation is particularly pronounced when carbonaceous wall materials are used. Dust particles can be transported in the tokamak over significant distances. Radioactivity leads to electrical charging of dust and to its interaction with plasmas and electric fields. This may cause interference with the discharge but may also result in options for particle removal. This paper discusses some of the multi-faceted problems using information both from fusion research and from low-temperature dusty plasma work.

The formation of dust particles in reactive plasmas affects the electrical characteristics of the plasma. We have investigated the time resolved development of the electrical characteristics due to particle formation, i.e. the voltage and current at the surface of the powered electrode in capacitively coupled Ar–C2H2 and Ar–CH4 dusty plasmas. The stray impedances of the reaction chamber were characterized in order to trace the change in plasma impedance during particle formation. Using a simple equivalent circuit model the plasma impedance is represented as a series combination of a resistor and a capacitor. It was observed that the plasma impedance becomes more resistive as the particles grow. In the case of Ar–CH4 plasmas three different characteristic steps were observed, which might be related to the nucleation, coagulation and agglomeration phase of particle formation. Compared with other dust particle detection methods this technique is easy to implement, non-intrusive and very sensitive even for the smallest particles.

We have studied the characteristic behaviour of dust particle formation in the capacitively coupled standard GEC cell using Ar/CH 4 methane and Ar/C 2 H 2 mixtures. Laser light scattering and absorption by dust particles, plasma emission, spectrum analysis for the change of plasma impedance by the presence of dust particles, atomic spectral emission by argon atoms, and mass spectroscopic measurements are performed in-situ. Using the 7th harmonic signal as an external control parameter, we have successfully deposited two-dimensional periodic structures of ‘dust dots’.

The formation of dust particles in argon diluted C2H2 plasmas was studied by means of Fourier transform infrared absorption spectroscopy and mass spectroscopy. The detection limit for infrared absorption was significantly improved by the use of a multipass technique. Measuring the intensity of the Rayleigh/Mie scattering of the infrared signal we found a periodicity of dust formation/vanishing (period of about 35 min in our experimental conditions). The fast disappearance of the dust from the plasma region at the end of every period is the evidence of a narrow particle size distribution, as confirmed by secondary electron micrographs of the collected powder. Characteristic infrared absorption features have their origin in absorption within the dust particles. Besides the strong presence of aliphatic hydrocarbons characteristic for amorphous hydrocarbon films, a significant amount of aromatic structures was detected. Heavy positive ions measured by ion-mass spectroscopy originate from polyacetilenic (C2nH2) and aromatic compounds. Time resolved mass spectra gave insight into the plasma response to the dust formation. &copy ; ; ; 2003 American Institute of Physics.

This paper deals with the study of the temporal and spatial evolution of the dust formation in a capacitively coupled standard GEC cell in Ar/C2H2 and Ar/CH4 mixtures. To initiate the particle growth in the Ar/CH4 discharge, we have either to apply transiently high power to the discharge or to inject transiently a pulse of C2H2. In the Ar/C2H2 discharge, however, the particles are formed spontaneously at constant low power. The experiments underline the importance of acetylenic compounds for the nucleation process, i.e. for the first step of particle growth. Due to the different initiation process, the further temporal evolution of the dust formation is significantly different for both kinds of discharges. The dust particles are detected by means of laser beam scattering and by measuring the extinction of the laser beam after passing the discharge. The response of the plasma to the formation of dust has been analysed by emission spectroscopy and mass spectroscopy. The 7th harmonic signal of the rf driving voltage is a useful indicator for the presence of dust particles and their growth.

Experiments are reported on the interaction of thin (d≈20 nm) evaporated silver films with the afterglow of an argon nitrogen microwave discharge. A strong increase in the resistivity of the thin silver film (from 2.2×10−8 to more than 10−3 Ω m) due to the interaction with the spatial afterglow of a nitrogen plasma was observed. The initial low resistivity could be recovered by increasing the sample temperature from room temperature to 420 K or by treatment with an argon plasma. The effect is thus reversible. Sputtering processes could not be observed in the spatial afterglow of nitrogen discharges. The experimental results are assigned to dissolved nitrogen compounds in the thin silver film. A possible mechanism for the reversible increase in film resistivity in the nitrogen afterglow may be strong electron localization at the nitrogen-induced lattice defects.

In this paper a spectroscopic investigation of an expanding surface wave produced plasma is presented. The electron temperature is evaluated by means of emission spectroscopy. The results show a strong and sharp increase of the electron temperature toward the end of the discharge, where the plasma is expanding into a region with lowered gas pressure.

Modulated beam mass spectroscopy is applied as a quantitative method for the measurement of the atomic nitrogen concentration in an expanding remote plasma. The plasma is created in a quartz tube by an electromagnetic surface wave (the upstream pressure ranges between 10 and 20 mbar). The recombined plasma with its N radicals is expanded into a reaction chamber where the pressure is about 10-3 mbar. In order to take into account the losses of atomic nitrogen by sticking and recombination at the inner walls of the mass spectrometer, a chopper has been inserted between the orifice of the mass spectrometer and the ionization chamber. Hence, the measured signal is separated into a beam and a background component, with different dependencies on the expansion properties. The beam-to-background ratio is found to depend on discharge parameters such as total pressure or gas mixture composition. A correction factor for the wall losses which is independent of these parameters allows the quantitative measurement of the N flux.

The properties of plasma-enhanced chemical vapour deposition (PECVD) coatings on polymer materials depend to some extent on the surface and material properties of the substrate. Here, isotactic polypropylene (PP) substrates are coated with silicon oxide (SiO x ) films. Plasmas for the deposition of SiO x are energetic and oxidative due to the high amount of oxygen in the gas mixture. Residual stress measurements using single Si cantilever stress sensors showed that these coatings contain high compressive stress. To investigate the influence of the plasma and the coatings, residual stress, silicon organic (SiOCH) coatings with different thicknesses between the PP and the SiO x coating are used as a means to protect the substrate from the oxidative SiO x coating process. Pull-off tests are performed to analyse differences in the adhesion of these coating systems. It could be shown that the adhesion of the PECVD coatings on PP depends on the coatings' residual stress. In a PP/SiOCH/SiO x -multilayer system the residual stress can be significantly reduced by increasing the thickness of the SiOCH coating, resulting in enhanced adhesion.

International audience

International audience; A power-modulated radio-frequency (f = 13.56 MHz) argon plasma supplied by reactive acetylene to deposit an amorphous hydrocarbon film on the electrodes is studied. The effects of gradual film deposition on electron density, electron temperature, argon metastable Arm(3P2) density, and dc-bias voltage are investigated. The time evolutions of plasma parameters during a pulsing cycle are studied as a function of the applied RF power and the thickness of the deposited film. Analytical estimations show a slower expansion of the sheath size and a slower decay of the ion flux after film deposition on the electrodes. The observed changes in the plasma parameters during the power-on and afterglow phases of the pulsed plasma can be correlated with the presence of impurities desorbed from the chamber walls in the discharge volume.

In a fusion reactor like ITER, in-vessel materials are subjected to interactions with the plasma. One of the main consequences of these plasma-material interactions is the creation of co-deposited layers. Due to internal stresses, part of these layers can crack leading to micro particle creation. The purpose of the following paper is to review the Tokamak operation processes which lead to erosion and layer creation. Then, the proportion of these layers that is converted into micro-particles will be evaluated in the case of Tore Supra experiments and extrapolated for ITER. It is major importance to measure the ITER mobilizable dusts present in the Vacuum Vessel and compare the measured quantity with the safety limits. When approaching these limits, removal systems must be used in order to control the in-vessel dust inventory. In the second part of the paper, diagnostics and removal system under development will be presented.

The formation mechanisms of dust particles in fusion devices and the possible interactions of dust with fusion plasmas are discussed. The growth of small particles in the plasma edge of fusion discharges is suggested in analogy to the well-known growth in reactive process plasmas (dusty plasmas). Results from the analysis of collected dust from TEXTOR-94 and first in situ observations by laser light scattering are presented, giving indirect evidence for some of the discussed mechanisms. Dust formation is an important PSI issue with serious potential implications and deserves future in depth studies.

Summary form only given. High Power Pulsed Magnetron Sputtering (HPPMS) is a recently developed Ionized Physical Vapor Deposition (IPVD) technique. A bias voltage is applied to the target for a few hundred microseconds with a frequency of a few hundreds of Hertz, delivering several kW cm−2 of power to the target. This results in the production of an ultra dense plasma with a high ionization degree, showing some peculiar behaviors.

Absorption spectroscopy is known to be a powerful tool to gain spatially and temporally resolved information on excited and reactive species in a plasma discharge. Furthermore, the interaction of the discharge with short intense laser pulses can trigger the ignition and the transition into other transient states of the plasma. In this context laser-assisted ‘pump-probe’ experiments involving simultaneously generated supercontinuum radiation yield highly temporally resolved and spatially well-defined information on the transient phenomena. In this paper we demonstrate the possibility for ‘pump–probe’ experiments by initiating breakdown on a picosecond time scale (‘pump’) with a high-power beam and measuring the broadband absorption with the simultaneously provided supercontinuum (‘probe’). Since both pulses are generated from the same mode-locked master oscillator, they have a strong level of synchronization.

International audience; Reactive RF plasmas are an excellent source for the production of nanoparticles. The field of application of nanoparticles is nowadays rapidly growing, as well as the request for investigations on the nanoparticle material itself. Thus, we deal with the emerging need for targeted sampling of nanoparticles from the plasma. We developed a sampling system based on the effect of thermophoresis on the transport of nanoparticles within the plasma bulk.

Zero-dimensional, space-averaged global models of argon dust-free and dusty afterglow plasmas are developed, which describe the time behaviour of electron n e(t) and Ar* metastable n m(t) densities. The theoretical description is based on the assumption that the free electron density is smaller than the dust charge density. In pure argon, fairly good agreement with the experimentally measured densities and their decay times in the afterglow is obtained when the electron energy loss term to the chamber walls is included in the electron energy balance equation. In dusty plasma afterglow, the agreement between theory and experiment is less satisfactory. The calculated metastable density is 3 times smaller than the measured one and the electron decay is much faster in the late afterglows. The difference should probably arise from the assumption that the electron energy distribution function is Maxwellian. Different sources of secondary electrons in the dusty plasma afterglow are analysed. Comparison of the model with experimental results of argon dusty plasma suggests that the metastable pooling could be the source of the experimentally observed electron density increase in the early afterglow but electron generation from metastable–dust interactions cannot be fully discarded.

Axial emission profiles in a parallel plate dc micro discharge (feedgas: argon; discharge gap d=1mm; pressure p=10Torr) were studied by means of time resolved imaging with a fast ICCD camera. Additionally, volt-ampere (V-A) characteristics were recorded and Ar* metastable densities were measured by tunable diode laser absorption spectroscopy (TDLAS). Axial emission profiles in the steady state regime are similar to corresponding profiles in standard size discharges (d=1cm, p=1Torr). For some discharge conditions relaxation oscillations are present when the micro discharge switches periodically between low current Townsend-like mode and normal glow. At the same time the axial emission profile shows transient behavior, starting with peak distribution at the anode, which gradually moves towards the cathode during the normal glow. The development of argon metastable densities highly correlates with the oscillating discharge current. Gas temperatures in the low current Townsend-like mode (T= 320-400K) and the high current glow mode (T=469-526K) were determined by the broadening of the recorded spectral profiles as a function of the discharge current., Comment: submitted to Plasma Sources Sci. Technol

Space resolved concentrations of helium He metastable atoms in an atmospheric pressure radio-frequency micro-plasma jet were measured using tunable diode laser absorption spectroscopy. The spatial profile of metastable atoms in the volume between the electrodes was deduced for various electrode gap distances. Density profiles reveal the sheath structure and reflect the plasma excitation distribution, as well as the dominance of the α-mode discharge. Gap width variations show the transition from a normal glow plasma to a pure sheath discharge. In order to analyse and verify the experimentally observed profiles of the metastable atoms, a two-dimensional simulation model was set up. Applying an appropriate He/N2/O2 chemistry model, the correlation between the metastable profiles and the underlying excitation mechanisms was obtained.

Metastable and electron densities of pulsed argon plasma containing nano‐sized particles were measured by the means of Laser Absorption Spectroscopy and Microwave Interferometry, respectively. Laser Induced Fluorescence was probing the Ar* metastable axial distribution during one dust growing cycle. The experimental results of the dust‐free and dusty plasma afterglow were compared to the results obtained by a global model.

Space- and time-resolved measurements of Ar (3P2) metastable atoms at the exit of an atmospheric pressure radio-frequency micro-plasma jet are performed using tunable diode laser absorption spectroscopy. The discharge features a coaxial geometry with a hollow capillary as the inner electrode and a ceramic tube with a metal ring as the outer electrode. Absorption profiles of metastable atoms and optical emission measurements reveal the dynamics and the filamentary structure of the discharge. Single filaments with a diameter of 125 µm and metastable densities of about 1013 cm−3 are observed. The average spatial distribution of Ar metastables is characterized with and without a target in front of the jet, showing that the target potential and, therewith, the electric field distribution substantially change the filaments' expansion. Together with a detailed analysis of the ignition phase and the discharge's behavior under pulsed operation, the results give an insight into the excitation and de-excitation mechanisms.