EPHIN (Electron Proton Helium Instrument)

The COSTEP sensor unit EPHIN
Figure 1: The COSTEP sensor unit EPHIN

The Electron Proton Helium Instrument on board the ESA/NASA spaceprobe SOHO is one of our instruments being part of the COSTEP experiment. It's objectives are to understand stationary processes in the solar atmosphere, energy depostion and particle acceleration in the solar atmosphere, composition of the solar atmosphere and to learn more about processes in the interplanetary medium.

EPHIN is a novel telescope for the measurement of energy spectra of electrons from 250 keV to more than 8.7 MeV and of hydrogen and helium isotopes from 4 MeV/n to more than 53 MeV/n. Charged particles are registered in the sensor by ionization. The EPHIN sensor consists of a semiconductor stack with five layers. They are enclosed by a sixth semiconductor detector and a scintillation detector, operated in anticoincidence.

The SOHO spaceprobe was launched at Cape Canaveral on December 2, 1995. EPHIN was switched on December 7, 1995. The primary mission started in March 1996 and ended in April 1998. Still today EPHIN works and sends data to Earth.

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The EPHIN pages are based upon
R. Müller-Mellin et. al.
COSTEP - Comprehensive Suprathermal And Energetic Particle Analyser
Solar Physics 162: 483-504, 1995