Home

keVedge

KeVedge is a term used in X-ray spectroscopy to denote the energy of a K-edge, expressed in kiloelectronvolts (keV). The K-edge marks the binding energy of the K-shell electrons in an atom. When photon energy is just below Eedge, K-shell photoionization is not possible; just above Eedge, photoelectric absorption increases sharply because K-shell ionization becomes possible. In observed spectra, this appears as a discontinuity or edge in the photoelectric absorption coefficient atop the continuum.

The exact edge energy depends on the element and its ionization state. For example, neutral iron has

In spectral modeling, keVedge or an edge component is used with parameters for Eedge and the associated

a
K-edge
near
7.112
keV,
while
neutral
oxygen’s
K-edge
is
around
0.543
keV.
The
edge
shape
is
influenced
by
atomic
structure,
solid-state
effects,
and
instrumental
response.
The
edge
depth,
often
described
by
an
optical
depth
parameter,
relates
to
the
column
density
of
absorbing
material
along
the
line
of
sight.
optical
depth
to
fit
absorption
features
and
to
infer
elemental
abundances
and
column
densities.
The
edge
energy
serves
as
a
diagnostic
of
chemical
composition
and
physical
conditions
in
astrophysical
plasmas,
interstellar
and
intergalactic
media,
and
in
the
calibration
of
X-ray
detectors.
The
concept
is
part
of
the
broader
study
of
photoelectric
absorption
and
absorption
edges
across
the
electromagnetic
spectrum,
with
K-edges
representing
a
key
subset.