Freiburg 2008 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

EP: Fachverband Extraterrestrische Physik

EP 8: The Sun and Heliosphere II

EP 8.8: Vortrag

Dienstag, 4. März 2008, 18:30–18:45, KGI-Aula

Helium energy spectra from 5 to >150 MeV/n from SOHO EPHIN — •Johannes Labrenz, Raúl Gómez-Herrero, Reinhold Müller-Mellin, Oliver Rother, and Bernd Heber — IEAP CAU Kiel

Since its launch in Dec 1995 the SOHO spacecraft is providing observations of energetic particles at the lagrangian point L1. On board is the Electron Proton Helium Instrument (EPHIN), which measures nominally electrons in the energy range from 250 keV to >10 MeV, protons from 4 MeV to >53 MeV and helium from 4 MeV/n to >53 MeV/n. The instrument is based on six semiconductor silicon detectors with an anticoincidence scintillator. The total thickness for stopping particles is 13.45mm. The well-proven De/dx-E method is used to determine energy and mass of the stopping particles. However, penetrating particles, i.e. electrons >10 MeV and nuclei >53 MeV/n, are registered in a single integral channel. In this work we make use of the dE/dx-dE/dx method and show that the energy range can successfully be extended to 150 MeV/n for helium. Energy spectra as well as their temporal evolution are presented in the investigation of the modulation of Anomalous cosmic rays (ACR) and Galactic cosmic rays (GCR).