CHARGING OF THE LISA TEST MASSES: SOURCES, CONSEQUENCES AND MANAGEMENT

摘要

Energetic particle radiation in the form of galactic cosmic rays and solar particles will cause the LISA test masses to become charged. This will give rise to disturbing forces on the test masses through both Lorentz and Couloumb interactions which can translate into acceleration noise, coupling of the spacecraft and test mass motion and coherent signals in the measurement bandwidth. To minimise these effects, the charge management system on LISA will control the amount of charge on the test masses through the photo-electric effect using a system of UV illumination. We present the estimates of the exposure of the spacecraft to energetic particles and the resultant test mass charging rates based on detailed charging simulations using GEANT4. We also describe the system used to measure and manage the charge on the test masses.