TY  - JOUR
A1  - Michalik-Onichimowska, Aleksandra
A1  - Beitz, Toralf
A1  - Panne, Ulrich
A1  - Löhmannsröben, Hans-Gerd
A1  - Riedel, Jens
T1  - Microsecond mid-infrared laser pulses for atmospheric pressure laser ablation/ionization of liquid samples
JF  - Sensors and actuators : B, Chemical
N2  - 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.
KW  - Laser ablation
KW  - Ion mobility spectrometry
KW  - Pulse duration
KW  - Plume
KW  - Ionization
Y1  - 2016
U6  - https://doi.org/10.1016/j.snb.2016.06.155
SN  - 0925-4005
VL  - 238
SP  - 298
EP  - 305
PB  - Elsevier
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Meier, Patrick
A1  - Motschmann, Uwe
A1  - Schmidt, Jurgen
A1  - Spahn, Frank
A1  - Hill, Thomas W.
A1  - Dong, Yaxue
A1  - Jones, Geraint H.
A1  - Kriegel, Hendrik
T1  - Modeling the total dust production of Enceladus from stochastic charge equilibrium and simulations
JF  - Planetary and space science
KW  - Enceladus
KW  - Plume
KW  - Nanograin charge
KW  - CAPS
Y1  - 2015
U6  - https://doi.org/10.1016/j.pss.2015.10.002
SN  - 0032-0633
VL  - 119
SP  - 208
EP  - 221
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Meier, Patrick
A1  - Kriegel, Hendrik
A1  - Motschmann, Uwe
A1  - Schmidt, Jürgen
A1  - Spahn, Frank
A1  - Hill, Thomas W.
A1  - Dong, Yaxue
A1  - Jones, Geraint H.
T1  - A model of the spatial and size distribution of Enceladus' dust plume
JF  - Planetary and space science
KW  - Enceladus
KW  - Plume
KW  - Nanograins
KW  - Cassini
KW  - Tail
Y1  - 2014
U6  - https://doi.org/10.1016/j.pss.2014.09.016
SN  - 0032-0633
VL  - 104
SP  - 216
EP  - 233
PB  - Elsevier
CY  - Oxford
ER  -