as in international and national standards The general meaning is unambiguous but a value depends on a number of conditions and the purpose Hence a clear on a numerical
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1
in radiation protection is still weak fr
in radiation protection is still weak from an up to date point of view in texts as
as in international and national standards. The general meaning is unambiguous, but a
value depends on a number of conditions and the purpose. Hence, a clear
on a numerical value of the energy threshold beyond a radiation has to be
as "ionizing " is still missing. The existing definitions are, therefore, either correct
very general or theoretical and hence not applicable. This paper reviews existing
and suggests
a a
a
a a
a
a a
a
takes about
eV of energy to produce a ionization. Most human exposures to radiation are of energies of
electron vol
2
ts (MeV) - energies at which many ioniza
ts (MeV) - energies at which many ionizations occur as the radiation passes through
a a
the
process is not the only process by which energy of the radiation may be transferred to a
A second important phenomenon is excitation, a process which can also have physical,
or biological consequences. A radiation, such as low energy photons, may be ionizing in one
but not in the choice of a suitable which a radiation is
as non-ionizing, will depend on circumstances. The definitions given in this report apply to
specified fixed cutoff value where relevant.
bestimmte Teilchenenergie als Grenze zwischen nichtionisierender
(zum Beispiel sicht
3
bares Licht) und ionisierender Strahlung
bares Licht) und ionisierender Strahlung la'Bt sich nicht angeben, da die
StoBionisation benotigte Energie auch von der Art des ionisierten Gases abhangt. Die in der
angewendeten Strahlungen haben im allgemeinen Teilchenenergien oberhalb 1 keV und
dehalb eindeutig zu den ionisierenden Strahlungen.
the energy needed to cause a valence electron to escape an
is of the order of 4 - 25 eV, radiations must carry kinetic or quantum energies in excess of this
to be called "ionizing". As will be seen, this criterion would seem to include electromagnetic
with wavelengths up to about 320 nm, which includes most of the ultraviolet (UV) radiatio
4
n
(~ 10 - 400 nm). However, for practic
n
(~ 10 - 400 nm). However, for practical purposes these marginally ionizing UV radiations are not
considered in the context of radiological physics, since they are even less capable of
through matter than is visible light, while other ionizing radiations are generally more
dieser Definition wird Strahlung
einer Energie uber 5keV als ionisierende Strahlung festgelegt. Eine physikalische Abgrenzung zu
Strahlung ist nicht moglich, weil die lonisation vom Material abhangig ist.
a a
a
a
a
a
a
A
6
a
a
a a
a
A
not a final
a
4 biological
N
a
E
a
1 a
a
a a
a a
a
a
a
takes cross
1 2
of Radiology, 6
1
2
A
from