@article{MichalikOnichimowskaBeitzPanneetal.2017, author = {Michalik-Onichimowska, Aleksandra and Beitz, Toralf and Panne, Ulrich and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Riedel, Jens}, title = {Microsecond mid-infrared laser pulses for atmospheric pressure laser ablation/ionization of liquid samples}, series = {Sensors and actuators : B, Chemical}, volume = {238}, journal = {Sensors and actuators : B, Chemical}, publisher = {Elsevier}, address = {Lausanne}, issn = {0925-4005}, doi = {10.1016/j.snb.2016.06.155}, pages = {298 -- 305}, year = {2017}, abstract = {In many laser based ionization techniques with a subsequent drift time separation, the laser pulse generating the ions is considered as the start time to. Therefore, an accurate temporal definition of this event is crucial for the resolution of the experiments. In this contribution, the laser induced plume dynamics of liquids evaporating into atmospheric pressure are visualized for two distinctively different laser pulse widths, Delta t = 6 nanoseconds and Delta tau = 280 microseconds. For ns-pulses the expansion of the generated vapour against atmospheric pressure is found to lead to turbulences inside the gas phase. This results in spatial and temporal broadening of the nascent clouds. A more equilibrated expansion, without artificial smearing of the temporal resolution can, in contrast, be observed to follow mu s-pulse excitation. This leads to the counterintuitive finding that longer laser pulses results in an increased temporal vapour formation definition. To examine if this fume expansion also eventually results in a better definition of ion formation, the nascent vapour plumes were expanded into a linear drift tube ion mobility spectrometer (IMS). This time resolved detection of ion formation corroborates the temporal broadening caused by collisional impeding of the supersonic expansion at atmospheric pressure and the overall better defined ion formation by evaporation with long laser pulses. A direct comparison of the observed results strongly suggests the coexistence of two individual ion formation mechanisms that can be specifically addressed by the use of appropriate laser sources.}, language = {en} } @article{MeierMotschmannSchmidtetal.2015, author = {Meier, Patrick and Motschmann, Uwe and Schmidt, Jurgen and Spahn, Frank and Hill, Thomas W. and Dong, Yaxue and Jones, Geraint H. and Kriegel, Hendrik}, title = {Modeling the total dust production of Enceladus from stochastic charge equilibrium and simulations}, series = {Planetary and space science}, volume = {119}, journal = {Planetary and space science}, publisher = {Elsevier}, address = {Oxford}, issn = {0032-0633}, doi = {10.1016/j.pss.2015.10.002}, pages = {208 -- 221}, year = {2015}, language = {en} } @article{MeierKriegelMotschmannetal.2014, author = {Meier, Patrick and Kriegel, Hendrik and Motschmann, Uwe and Schmidt, J{\"u}rgen and Spahn, Frank and Hill, Thomas W. and Dong, Yaxue and Jones, Geraint H.}, title = {A model of the spatial and size distribution of Enceladus' dust plume}, series = {Planetary and space science}, volume = {104}, journal = {Planetary and space science}, publisher = {Elsevier}, address = {Oxford}, issn = {0032-0633}, doi = {10.1016/j.pss.2014.09.016}, pages = {216 -- 233}, year = {2014}, language = {en} }