commit a6b620306bb85e5ee0ae703be77f077e682cc046 Author: Georg Schlisio Date: Fri Jun 30 14:05:28 2023 +0200 current state of the manuscript - early stage diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..bee6b7c --- /dev/null +++ b/.gitignore @@ -0,0 +1,9 @@ +*aux +*swp +*bbl +*blg +*log +*out +*synctex.gz +*bib +~$* diff --git a/Manuscript outline_2.docx b/Manuscript outline_2.docx new file mode 100644 index 0000000..4b21a76 Binary files /dev/null and b/Manuscript outline_2.docx differ diff --git a/img/Figure_1.pdf b/img/Figure_1.pdf new file mode 100644 index 0000000..69bac50 Binary files /dev/null and b/img/Figure_1.pdf differ diff --git a/img/isotope_molecules_mass_peak_overload.png b/img/isotope_molecules_mass_peak_overload.png new file mode 100644 index 0000000..1d36b8d Binary files /dev/null and b/img/isotope_molecules_mass_peak_overload.png differ diff --git a/manuscript.pdf b/manuscript.pdf new file mode 100644 index 0000000..33ab280 Binary files /dev/null and b/manuscript.pdf differ diff --git a/manuscript.tex b/manuscript.tex new file mode 100644 index 0000000..dbd134e --- /dev/null +++ b/manuscript.tex @@ -0,0 +1,187 @@ +\documentclass[% +superscriptaddress, +% aip, +iop, +% jmp, +% bmf, +% sd, +% rsi, +amsmath,amssymb, +preprint,% +% reprint,% +%author-year,% +author-numerical,% +% Conference Proceedings +]{revtex4-2} + +\usepackage{graphicx}% Include figure files +\usepackage{dcolumn}% Align table columns on decimal point +\usepackage{bm}% bold math +%\usepackage{filecontents} + +\usepackage[utf8]{inputenc} +\usepackage[T1]{fontenc} +\usepackage{mathptmx} +\usepackage{gensymb} +\usepackage{amsmath} +\usepackage[colorlinks=true,allcolors=black]{hyperref} +\usepackage{multirow} +\usepackage{booktabs} +\usepackage[exponent-product=\cdot]{siunitx} +\usepackage{chemformula} + +\begin{document} + +\preprint{PREPRINT: DRAFT} + +\title[Test operation of a novel Time-Of-Flight mass spectrometer on the gas exhaust of Wendelstein 7-X]{Test operation of a novel Time-Of-Flight mass spectrometer on the gas exhaust of Wendelstein 7-X} + +\author{G. Schlisio} +\email{georg.schlisio@ipp.mpg.de} +\affiliation{ + Max-Planck-Institut für Plasmaphysik, Wendelsteinstra{\ss}e 1, 17491 Greifswald, Germany +} +\author{S. Gasc} +\affiliation{ + Spacetek Technology AG, Brüggliweg 18, 3073 Gümligen, Switzerland +} +\author{L. Hofer} +\affiliation{ + Spacetek Technology AG, Brüggliweg 18, 3073 Gümligen, Switzerland +} +\author{C.C. Klepper} +\affiliation{ + Oak Ridge National Laboratory, Oak Ridge, Tennesse 37831, USA +} +\author{the W7-X team\footnote{See author list of Thomas Sunn Pedersen et al 2022 Nucl. Fusion 62 042022}} + +\date{\today}% It is always \today, today + +\begin{abstract} + A novel time-of-flight mass spectrometer was operated in Wendelstein 7-X, a magnetic confinement fusion (MCF) experiment, to assess the suitability and limitations in the use for gas exhaust analysis in MCF devices. + With a focus on high mass resolution sufficient for isotope separation, the permanent presence of magnetic field and a need for fast time resolution MCF presents a challenging environment for the operation of such devices. + +% TODO continue + +\end{abstract} + +\maketitle + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\section{\label{sec:intro}Introduction} + +Mass spectrometers of various measurement principles are indispensable in many applications, vacuum quality monitoring and gas composition being a prominent one. +Wendelstein 7-X (W7X) is an optimized modular stellarator experiment dedicated to magnetic confinement fusion research in high-temperature plasmas [TODO reference]. %TODO +Time-of-flight mass spectrometers (TOF-MS) measure mass to charge ratio m/z by accelerating ions against a retarding field and measure the response time in a detector. +The flight time is directly proportional to the ions m/z ratio, which allows the mass-resolved measurement of the injected ions. +The IonTamer® FA (ITFA) is a novel TOF-MS . %TODO +Possible applications of a fast high-resolution mass spectrometer in magnetic confinement fusion (MCF) research and future fusion reactors: +\begin{itemize} +\item Gas exhaust monitoring, especially accounting of DT fuel +\item He exhaust monitoring, e.g. for divertor effectiveness and efficiency +\item Impurity monitoring, e.g. for assessment of plasma chemistry and vacuum quality +\end{itemize} + +\section{Residual magnetic field influence on the TOF-MS measurement} +Many mass analyzers require free-streaming charged particles, and TOF-MS share this property. Fast free streaming particles are subject to a Lorentz force in a magnetic field. While MCF employs toroidal fields with a quadrupole far field characteristics, residual fields of several mT cannot entirely be avoided at reasonable distance of the torus system. +Therefore, magnetic shielding is frequently employed to reduce the residual magnetic field down to an acceptable level. +Over the test duration, we successively improved the magnetic shielding in steps and document the effect below. +While the residual field could not be measured in-situ, calculation of the residual field vectors were performed and the shielding structure was subjected to measurements in a test magnet setup thereafter. + +\section{Dynamic range dependence on pressure} +The TOF-MS is designed for pressures up to \SI{1e-3}{\pascal}. +Higher pressure means higher signal +Sudden changes in pressure can lead to safety deactivation of the instrument + + +%(ANALYSIS HINT: take data from 20230307 where we reach transient saturation at some point and a short pumpdown at ~12:57CET reduces pressure and signal drastically; see also data taken on 2023-03-09: stepwise h2 pressure increase up to saturation, subsequent tuning-down of the gain, and pressure increase up to 1e-5mbar, gain scan at elevated pressures and a comparison with the ITMS and its spectra; see also 50ks=13.9h integration spectrum @~2e-8mbar 20230309) + +\section{Time response} +Observing gas dynamics in the fusion exhaust requires a sub-second time resolution, which is often detrimental to dynamic range of instruments, as longer integration times give higher signal-to-noise ratio. +The ITFA in its present hard- and software configuration has a minimum integration time of \SI{0.1}{\second}, which in turn already contains the average of 1000 scans. + + +\section{Mass range} +The mass range of the ITFA is defined by hardware settings to ~\SI{1300}{u}. +Most of this range is of interest only for analysis of larger compounds, as found in chemistry analysis \cite{Gasc2022}. +For the purpose of fusion gas exhaust monitoring, a mass range up to \SI{100}{u} is mostly sufficient and a limitation of the mass range leads - due to the nature of a TOF - to significantly reduce data data footprint and lead to a speed-up, improving the time response. + + +\section{Observation of isotopes in common molecules} +While W7X does currently only run Hydrogen, and neither Deuterium nor Tritium is present in the machine, the question of deuterated and tritiated molecules poses itself in view of Deuterium-Tritium fuel foreseen for reactors. W7X is planning for Deuterium operation in the next years, Tritium will be utilized in ITER and beyond. +Identifying fuel-carrying molecules and precisely accounting for fuel will be a relevant and challenging part of the fusion fuel cycle. + +While new developments \cite{Day2019,Haertl2022} promise to extract over 90\% of the Tritium via direct internal recycling, the remaining mixture remains to be analyzed and monitored. +Due to the unavailability of D and T in the experimental setup, simulations have been performed and are presented here along with measurements as a prediction of the TOF-MS capabilities in this regard. + +\section{Other notable findings} +During operation of the ITFA in hydrogen-dominated sampling gas a prominent mass peak at $ \text{m}/\text{Z} = 3.024$ was reliably observed. +This corresponds to thrice the hydrogen mass and relates to \ch{H3+}, a molecule long known \cite{Thomson1911} and special relevance in astrophysics. +According to literature, it forms with a proton transfer process \ch{H2 + H2+ -> H3+ + H} which occurs in the ITFA analyzer. +This effect is well-documented \cite{Gauthier1995} but not common knowledge. + +\section{Discussion} +Future development of the ITFA and its analysis tools are planned, with features like mass range selection. + +\section*{Declaration of the authors} +The authors declare that SG and LH are employed by Spacetek Technologies AG, manufacturer and marketer of the discussed ITFA. + +\begin{acknowledgments} + The authors wish to acknowledge the support of S. Vartanian and E. Gauthier for discussions on H3+. + The authors further wish to acknowledge the fine lab work of A. Graband in support of the ITFA test, especially with regard to the magnetic shielding. + + This work has been carried out within the framework of the EUROfusion + Consortium and has received funding from the Euratom research and + training programme 2014-2018 and 2019-2020 under grant agreement No + 633053. The views and opinions expressed herein do not necessarily + reflect those of the European Commission. +\end{acknowledgments} + +\appendix + +\nocite{*} + +\begin{thebibliography}{10} + + \bibitem{Gasc2022} + S. Gasc, L. Hofer, Chimia 2022, DOI: 10.2533/chimia.2022.52 + + \bibitem{Schlisio2019} + G. Schlisio et al, RSI 2019, DOI: 10.1063/1.5098125 + + \bibitem{Schlisio2021} + G. Schlisio et al, NF 2021, DOI: 10.1088/1741-4326/abd63f + + \bibitem{Thomson1911} + Thomson, J. J. (1911). XXVI. Rays of positive electricity. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 21(122), 225-249. + + \bibitem{Gauthier1995} + E. Gauthier, (1995). Quantitative analysis of deuterium and helium after plasma shots by means of resolved mass spectrometry (EUR-CEA-FC--1557). France %(https://inis.iaea.org/search/search.aspx?orig_q=RN:27073670) + + \bibitem{McCall2000} + McCall Phil.Trans.R.Soc.Lond.A 2000, DOI: 10.1098/rsta.2000.0655 (H3+ spectroscopy) + + \bibitem{Day2019} + Day FusEngDes2019 https://doi.org/10.1016/j.fusengdes.2019.04.019 + + \bibitem{Haertl2022} + Haertl FusEngDes22 https://doi.org/10.1016/j.fusengdes.2021.112969 + + %\bibitem{loarer2005} % no DOI found, see https://inis.iaea.org/search/search.aspx?orig_q=RN:36078348 + %T. Loarer, et al., 20th IAEA fusion energy conference proceedings (2005): 36078348. + +% \bibitem{Grote2003} % DOI https://doi.org/10.1016/S0022-3115(02)01503-9 +% H. Grote, et al., J.Nuc.Mat. Volumes 313–316, March 2003, Pages 1298-1303 + +% \bibitem{Haas1998} +% G. Haas, H.-S. Bosch, Vacuum 51.1 (1998): 39-46. % DOI https://doi.org/10.1016/S0042-207X(98)00131-6 + +% \bibitem{Wenzel2019} +% U. Wenzel, et al., RSI (2019) % DOI https://doi.org/10.1063/1.5121203 + +% \bibitem{Kremeyer2020} +% T. Kremeyer, et al., RSI (2020) % https://doi.org/10.1063/1.5125863 + +\end{thebibliography} + +\end{document} \ No newline at end of file