Techniques for mass resolution improvement achieved by typical plasma analyzers: Modeling and simulations 1 G. Nicolaou, 1 M. Yamauchi, 1 M. Wieser, 1 S. Barabash, 2 A. Fedorov 1 Swedish Institute of Space Physics (IRF), Kiruna, Sweden 2 Institut de Recherche en Astrophysique et Planetologie (IRAP), CNRS/Universite de Toulouse, Toulouse, France Higher mass resolution → answer science questions Distinct Nitrogen ion at Earth’s environment: Origin of life (ancient atmospheric composition) Planetary atmosphere (origin and evolution) Example Motivation

Techniques for mass resolution improvement achieved by typical plasma analyzers: Modeling and simulations 1 G. Nicolaou, 1 M. Yamauchi, 1 M. Wieser, 1 S. Barabash, 2 A. Fedorov 1 Swedish Institute of Space Physics (IRF), Kiruna, Sweden 2 Institut de Recherche en Astrophysique et Planetologie (IRAP), CNRS/Universite de Toulouse, Toulouse, France Deflectors: Elevation Angle Electrostatic Analyzer: Energy/charge Magnetic separator: mass/charge STEP 1 Use simulation software (SIMION) to cross- calibrate an instrument design e.g.: Ion Composition Analyser (ICA) on board Rosetta STEP 1 Use simulation software (SIMION) to cross- calibrate an instrument design e.g.: Ion Composition Analyser (ICA) on board Rosetta

Techniques for mass resolution improvement achieved by typical plasma analyzers: Modeling and simulations 1 G. Nicolaou, 1 M. Yamauchi, 1 M. Wieser, 1 S. Barabash, 2 A. Fedorov 1 Swedish Institute of Space Physics (IRF), Kiruna, Sweden 2 Institut de Recherche en Astrophysique et Planetologie (IRAP), CNRS/Universite de Toulouse, Toulouse, France STEP 2 Modify geometry to increase resolution at: Specific mass species (C,N,O) Low energy range ( eV/q) STEP 2 Modify geometry to increase resolution at: Specific mass species (C,N,O) Low energy range ( eV/q)

Step 1: Cross-calibration Ion Composition Analyzer (ICA) on ROSETTA Ion Mass Analyzer (IMA) on Mars Express and Venus Express Electrostatic Analyzer

Step 1: Cross-calibration 3d SIMION simulations of ICA and IMA instruments on board Rosetta and Mars and Venus Express respectively Position of species on MCP Examine the position/shape of the peaks Future tasks: Detailed adjustment of magnets/B-field Compare with flight data

Ion Composition Analyser (ICA) on board Rosetta Mass peaks and shapes for specific post acceleration voltages and energies Step 1: Cross-calibration

Ion Mass Analyser (IMA) on Mars Express Mass peaks and shapes for specific post acceleration voltages and energies Step 1: Cross-calibration

Ion Mass Analyser (IMA) on Venus Express Mass peaks and shapes for specific post acceleration voltages and energies Step 1: Cross-calibration

Checked the position of the detected species as a function of energy The “knee” of the spectrograms is reproducible Future tasks: Examine differences Check response of different sectors Adjust magnets/B-field * The above figures are to be qualitatively compared (not exact same case) Step 1: Cross-calibration Position vs Energy mass lines from flight data FlightSimulation

Step 2: modifications Units to modify: Size and shape of the magnets Location of the magnets: magnetic assembly structure Size and shape of the ESA Voltage settings (e.g. post acceleration unit) MCP location

Step 2: modifications Simplified geometry tests: Larger magnets → bigger particle paths inside the assembly Smaller azimuth sectors → Limits the azimuth spread on the detector Bigger ESA → different angle of entry in the assembly → bigger path MCP location adjusted to the focal points → have to be optimal for the energy range we are interested

Step 2: modifications Counts vs radial distance on MCP ↓

More to be considered Shape of the magnets for better focusing: Fringe fields: sector sizes, magnetic assembly structure: Magnetic field in the center of the magnetic assembly Scattered beam gets focused on the detector more effectively for different magnet shapes

More to be considered Proton scatter: Proton’s can be reflected on the instrument’s wall. Shape of wall can trap protons Shape of the MCP: Cone shaped MCP → particles hit the detector vertically Focusing properties of the ESA: Control the spread of particles in the ESA so we the azimuth resolution is not reduced Use non-uniform sized sector’s : Less magnets for total mass reduction

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