New TDS software for computer-based optimisation of thermodynamic conditions in Advanced Environmental Scanning Electron Microscopy (A-ESEM)

0568607 - ÚPT 2023 RIV CZ eng A - Abstract
Neděla, Vilém - Tihlaříková, Eva - Macálka, A. - Martinů, P.
New TDS software for computer-based optimisation of thermodynamic conditions in Advanced Environmental Scanning Electron Microscopy (A-ESEM).
16th Multinational Congress on Microscopy, 16MCM, 04-09 September 2022, Brno, Czech Republic. Book of abstracts. Brno: Czechoslovak Microscopy Society, 2022 - (Krzyžánek, V.; Hrubanová, K.; Hozák, P.; Müllerová, I.; Šlouf, M.). s. 148-149. ISBN 978-80-11-02253-2.
[Multinational Congress on Microscopy /16./. 04.09.2022-09.09.2022, Brno]
R&D Projects: GA ČR(CZ) GA19-03909S; GA MPO(CZ) EG17_176/0015020
Institutional support: RVO:68081731
Keywords : CFD simulations * ESEM * regression methods * machine learning * thermodynamic conditions * humidity
OECD category: Computer hardware and architecture
https://www.16mcm.cz/wp-content/uploads/2022/09/16MCM-abstract-book.pdf

Environmental scanning electron microscope (ESEM) allows direct observation of electrically non-conductive and fully hydrated samples from living and non-living nature with minimal
preparation or in fully native state under elevated gas pressure (tens to thousands of Pa) and electron beam energy (1 - 20 keV). Dynamical in situ studies of sample hydration, drying or static observation under conditions of thermodynamic equilibrium are possible when water vapour pressure and sample temperature are precisely controlled. This is a key factor for successful observations, but also a major challenge, as these parameters are difficult to accurately measure in close vicinity to irradiated sample surface. Consequently, new observation methods based on mathematical and physical simulations (computational fluid dynamics, electron interactions etc.) are necessary. These methods, high efficiency detectors, custom designed hardware and software for the Advanced ESEM (A-ESEM) is developed by our scientific group. New Thermo-Dynamic Software (TDS) for simulation of water vapour pressure, sample surface temperature and relative humidity (RH) was developed within a grant cooperation of Environmental electron microscopy group and private company NUM solution. The TDS allows very fast and precise determination of environmental conditions suitable for the different observation in ESEM Quanta 650 FEG. Parameters as working distance, type of the sample and sample holder geometry are considered and final working conditions (temperature/pressure/RH) are calculated according to operator’s requirement. Thermo-dynamical conditions, calculated for the individual experiment guarantee successful results of observation in the A-ESEM. From these outputs, the user is able to see conditions in close vicinity around the sample, the gun above it and the detector. TDS is based on combination of computational fluid dynamics (CFD), numerical simulations in ANSYS CFX and the support vector regression method (ε-SVR) which was used to predict the output results. The regression algorithm is based on machine learning - support vector machine which works on statistical learning theory. Accuracy of the TDS software was tested in experimental measurements using humidity sensors. The ability of the TDS to simulate parameters for dynamical in-situ observation under 100% RH was tested on water droplet formation. Results show that the TDS software allow easy, fast and highly precise determination of working parameters directly according to requirements of the experiment.
Permanent Link: https://hdl.handle.net/11104/0339876