Development of a Time of Flight section for a Mass Spectrometer for the future Plasma Observatory mission.

In this presentation we report on the development of an Ion mass instrument onboard of small Sat as part of the Plasma Observatory mission. This new Ion Mass Spectrometer that will be developed for this mission is similar to the IES-D instrument successfully flown on the Cluster II mission. The IMS instrument developed for the THOR mission. The TOF (Time of Flight) section is similar but smaller than designed for the THOR mission. That clearly indicates a high level of heritage of this Mass Spectrometer. Hence this IMCA like instrument for Plasma Observatory this is a new instrument that will have a smaller TOF chamber we have redesigned the TOF section by using SIMION and TRIM simulations to evaluate the performance/geometric factor of this new instrument and the effect of thin carbon foils. The first results of this study indicated that we will be able to measure Hydrogen, Helium and Oxygen ions with sufficient high statistic in all science areas of this mission. covering the thermal and suprathermal energies, with a time resolution enabling to resolve ion scales and an energy and angular resolution permitting to study the non-Maxwellian features in distribution functions. Thus, the energy range will be 10eV - 30keV with a 20% resolution, a temporal resolution: 2s and an angular resolution: 22.5°. It is also planned to add a flux reducer to this sensor the handle a large dynamic range. In this presentation we will report on the current status of this development.