EPHIN - the Kiel particle experiment on SOHO
The electron
proton helium
instrument (EPHIN)
on board the ESA/NASA spaceprobe
SOHO (Solar and
Heliospheric Observatory)
is part of the
COSTEP experiment (Comprehensive
Suprathermal
and Energetic Particle Analyzer),
a international collaboration to investigate
energetic charged particles
of solar, planetary, interplanetary and galactic origin
in the inner solar system.
The experiments COSTEP and
ERNE
comprise the
CEPAC experiment (COSTEP-ERNE
Particle
Analyzer Collaboration)
on board of SOHO.
An identical instrument has been planned to be flown in the
AXAF-Mission.
Scientific objectives of the EPHIN experiment
- Stationary processes in the solar atmosphere,
- energy depostion and particle acceleration in the solar atmosphere,
- composition of the solar atmosphere,
- processes in the interplanetary medium.
Design of the EPHIN sensor
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/nucleon to more than 53 MeV/nucleon.
Charged particles are registered in the sensor by ionization.
The
EPHIN sensor
consists of a semiconductor stack (A through E) with five layers.
They are enclosed by a sixth semiconductor detector (F) and
a scintillation detector (G), operated in anticoncidence.
Time schedule of the EPHIN experiment
- Launch of the SOHO spaceprobe at Cape Canaveral: 2-Dec-1995
at 0808 UTC
- First switch on of the EPHIN sensor: 7-Dec-1995
- Arrival at target position (Lagrange point L1, 1.5 million km from
the earth) and start of the primary mission: March 1996
- end of the primary mission: April 1998
- end of (so far uncommisioned) secondary mission: April 2002
- References:
-
R. Müller-Mellin et al.
COSTEP - Comprehensive Suprathermal and Energetic Particle Analyzer.
Solar Physics 162, 483-504, 1995.
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kunow@kernphysik.uni-kiel.de