VISUALIZATION OF THE SUPERSONIC GAS JETS, SEEDED
WITH COPPER ATOMS, WITH PLIF-TECHNIQUE IN NUCLEAR
SPECTROSCOPY STUDIES
ALEXANDRA ZADVORNAYA (INSTITUTE FOR NUCLEAR AND RADIATION PHYSICS. KU LEUVEN )
The purpose of this work is to study the formation and characteristics of the supersonic gas jets created
in a special type of convergent-divergent nozzle, known as ‘de Laval’. Besides its standard application
in steam turbines and rocket engines [1], the ‘de Laval’ nozzle is proposed to be used in spectroscopic
studies of short-lived radioactive isotopes in the framework of the new IGLIS technique; and thus,
characterization of the new technique must be done in details. The In-Gas-jet Laser Ionization and
Spectroscopy (IGLIS) technique is based on in-gas-jet resonance ionization spectroscopy using highpower, high-repetition-rate, narrow-bandwidth lasers and heavy elements’ isotopes [2]. Reduction of
Lorentz and Gauss broadening is essential for laser spectroscopy studies and can be achieved while
accelerating gas flow up to the supersonic velocities in ‘de Laval’ nozzle.
Experimental setup optimization requires more studies on gas jet formation processes: in advance via
computer simulations and also experimentally. Computer simulations were performed in COMSOL
Multiphysics software (Figure 1). During the experiment the Planar Laser-Induced Fluorescence (PLIF)
technique [3] was applied to visualize the supersonic argon gas jet seeded with copper atoms in order
to: 1) compare the jet structure with the computer simulations results, 2) verify the jet parameters fulfill
the optimal experimental conditions required for spectroscopy and isotope’s ion production. Measuring
the relative density, velocity and temperature profiles of the gas jet is possible through exiting the
fluorescence radiation transition of the copper atoms with the UV-laser light at a wavelength within
copper absorption range.
The original supersonic gas jet images were obtained with an ICCD camera for different cases of
background pressure (Figure 2) and will be presented in the current contribution together with a detailed
comparison with the computer simulations results.
[1] Sutton, George P. and Biblarz, Os., Rocket Propulsion Elements, A Wiley-Interscience Publication,
chapter 3, 2010
[2] R. Ferrer et al., NIM B 3187B (2014) p. 570-581.
[3] Noel T. Clemens, Encyclopedia of Imaging Science and Technology by Joseph P. Hornak, A WileyInterscience Publication, p. 390 - 419, 2002
Supersonic gas jet velocity profile for the case of the optimal
background pressure.
PLIF-images of the supersonic gas jet for 3 different cases of
the background pressure.