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Visualization of laser-induced liquid micro-jet disintegration by means of high-speed video stroboscope

Stasicki, Boleslaw and Abel, B. and Charvat, A. and Faubel, M. (2004) Visualization of laser-induced liquid micro-jet disintegration by means of high-speed video stroboscope. In: 26th International Congress on High-Speed Photography and Photonics. 26th International Congress on High-Speed Photography and Photonics, 2004-09-19 - 2004-09-24, Alexandria, Virginia (USA).

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Abstract

In the present paper we describe a novel approach to monitor and to investigate laser induced liquid water jet disintegration in air and in vacuum. The features of liquid beam disintegration in vacuum are of importance for pulsed laser induced liquid beam desorption mass spectrometry and micro-calorimetry. Due to the small liquid beam diameter of 12-15 µm, its high speed of 50-100 m/s, and a total event duration of a less than a few microseconds only, the microscopic visualization of the jet disintegration was a challenging task. Good quality video sequences have been recorded with a high-speed video stroboscope system running in the back illumination mode. The light pulses were synchronized carefully with the shutter circuit of the stroboscope camera and the IR-laser pulses. With a continuously changing time delay between the desorption laser pulses and the shutter opening a slow-motion effect has been achieved. The delay was changed in steps of 25 ns which corresponds to an equivalent framing speed of about 40,000,000 fps. With a high-brightness light emitting diode (LED) as a light source an exposure time of about 200 ns an effective time resolution of several hundred nanoseconds could be achieved. Using a pulsed Nd:YAG laser instead, the exposure time and time resolution could be reduced down to about 10 ns and 25 ns, respectively. Due to the well known speckle problem when using coherent light sources for illumination we have finally used a Nd:YAG laser excited dye solution of Rhodamine 6G (10-3 M) in methanol solution in a quartz cuvette placed in front of the liquid beam keeping the short exposure time of about 10 ns. In this nearly speckle free visualization mode the real-time slow-motion imaging of the jet disintegration and the study of the desorption process has been made possible with a time resolution of 25 ns (currently limited by the phase shifter steps) and an exposure time of ~10 ns only. It has been found that the laser induced desorption is so fast that the measurement in the gas phase represents a “snapshot” of the situation (structure, complexation, interaction) in solution. The new desorption technique enables very promising studies of the function, structure and interaction of biopolymers in their natural environment.

Document Type:Conference or Workshop Item (Speech)
Additional Information: LIDO-Berichtsjahr=2004, monograph_id=Session 9,
Title:Visualization of laser-induced liquid micro-jet disintegration by means of high-speed video stroboscope
Authors:
AuthorsInstitution or Email of Authors
Stasicki, BoleslawUNSPECIFIED
Abel, B.Universität Göttingen
Charvat, A.Max-Planck-Institut für Biophysikalische Chemie
Faubel, M.Max-Planck-Institut für Strömungsforschung
Date:2004
Journal or Publication Title:26th International Congress on High-Speed Photography and Photonics
Refereed publication:No
In SCOPUS:No
In ISI Web of Science:No
Editors:
EditorsEmail
Thompso, UNSPECIFIED
Status:Published
Keywords:High-speed stroboscopy, liquid water micro-jet disintegration, liquid beam desorption mass spectrometry, biopolymers
Event Title:26th International Congress on High-Speed Photography and Photonics
Event Location:Alexandria, Virginia (USA)
Event Type:international Conference
Event Dates:2004-09-19 - 2004-09-24
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Flight Physics
Location: Köln-Porz , Braunschweig , Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology
Deposited By: Ilka Micknaus
Deposited On:15 Feb 2006
Last Modified:27 Apr 2009 05:00

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