Page 207 - Open-Hole Log Analysis and Formation Evaluation

.
ray
the
stages
“dead
strikes
Today,
has
of light
shower
releases
measure
produce
electrical
a
becoming
the
‘containing
until
logging
then
the
radioactivity
time”
OPERATING
Traditionally,
struck
a
field
resistor
to
the
350
350
may
bundle
crystal,
and
two
practically
silver-magnesium.
montmorillonite
final
to
strikes
4.3%
a
swamped
be
of
of electrons.
a.sodium
a
all
industry:
can
4
strike
clay
by
types
give
Each
due
PRINCIPLE
sodium
This
a
number
of
to
and
iodide
contains
OF
electrode
gamma
electrons.
potassium,
another
register
8%
iodide
minerals
photon,
voltage
single photon
less
ray
process
numerous
gamma
crystal
photocathode
is
of gamma

20,000
These,
vary
many
GAMMA
20,000.
ray
practically
Geiger-Mueller
than
pulse
tools
conducts
crystal.
when
(fig.
in
the presence
electrode,
made
signals.
no
of light
a
RAY
1%.
and
is
The
use
potassium
per
repeated
counts
turn,
is
which
from
10.4).
hitting
detectors
small
unit
are
per
TOOLS

hard
system
‘Lithology
the
Qpenhole
producing
emitted.
potassium,
have
signals
to
When
of dissolved
through
cesium
an
has
a
:
a
scintillation
current
scintillation
a
(Appendix
that
This
(SGT)
of time).
second
(NGT)
find.
Occasionally,
been
a
even
3.5%
accelerated
tiny
4),

gamma
in
number
potassium
used
antimony
through
detectors.
or
or
very short
natural
without
photocathode,
flash
ray
and
potas-
bigger
detectors
an
‘in
gamma
Because
of
a_

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FIGURE 10.1 Classification of the Radioactive Disintegration Series.