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29 September 2004 New estimates of test-mass charging in the LISA mission
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The accretion of electrostatic charge in the isolated LISA test masses due to energetic particles in the space environment hinders the drag-free operation of the gravitational inertial sensors. Robust predictions of charging rates and associated stochastic fluctuations are therefore required for the exposure scenarios expected throughout the mission. We report on detailed charging simulations with the Geant4 toolkit, using comprehensive geometry and physics models, for galactic cosmic-ray protons and helium nuclei. These predict net charging rates of up to +100 elementary charges per second during the solar minimum period, decreasing by half at solar maximum. Charging from sporadic solar events involving energetic protons was also investigated. Other physical processes hitherto overlooked as potential charging mechanisms have been assessed. Significantly, the kinetic emission of very low-energy secondary electrons due to bombardment of the inertial sensors by primary cosmic rays and their secondaries can produce charging currents comparable with the Monte Carlo rates.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Henrique Araujo, Peter Wass, Diana Shaul, and Timothy John Sumner "New estimates of test-mass charging in the LISA mission", Proc. SPIE 5500, Gravitational Wave and Particle Astrophysics Detectors, (29 September 2004);

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