line" analysis such as analysing the suplhur content of oil etc;
(2)
Gamma logging instruments:
seams. The logging instrument
These are used for finding coal
equipped with a cobalt-60 source
and a detector is placed into a borehole. The gamma rays emmitted
in all
radiation in different ways,
directions. Since
gamma
different levels of gamma radiation.
thickness of the coal seam can be accurately distuinguished
measured.
from the cobalt-60 penetrate the walls of the bore hole
coal seams and rock strata scatter and absorb
detector the
measures
As a result, the depth and
and
(3)
Neutron
logging
instruments:
exploitation of oil fields.
These are
used
in
the
The logger, equipped with a neutron
The neutron source gives
off
source, is placed in a borehole. fast neutrons in all directions. Hydrogen is very good at slowing down neutrons. Other elements are not so effective.
down neutrons are captured by other
The slowed
elements and
a
nuclear
reaction (n, gamma) occurs in which gamma radiation is given off. measuring the intensity of the gamma radiation it is possible to discover the hydrogen content of the rock strata and work
By
out
levels. Neutron logging
the position of
oil,
gas and water
provides
reliable
data
to aid the
rational
exploitation
and
consistently high production of oil fields.
1.
The use of excitation and ionization
The following isotopic instruments have been designed on the principle that matter is excited and ionized through irradiation. (1) Ionic smoke detector and automatic fire alarm: This uses the
effect of radiation from a radio-isotope on air
ionization
and
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