Exploranium KT-9 User Manual page 83

In the field
In most field conditions, rock samples being measured have
uneven surfaces. In this case, the P
advantages.
P Mode
IN
Field experience has shown
that effects due to surface
unevenness is minimized in
the P mode.
IN
By taking a series of measure-
ments (5 minimum) over vari-
ous portions of the rock
sample, and using the KT-9's
averaging ability, the truest
value of the samples suscepti-
bility is obtained. This is due
to the pin sometimes being
placed on a peak or valley of
the surface.
In most cases the outer thin layer of the rock is oxidized
(weathered) and the susceptibility value from this thin layer is
not representative of the actual sample.
The KT-9 has an air-cored coil and 80% of the measured signal
arises from a 20mm layer below the face of the coil.
The pin spaces the coil away
from the weathered surface
and minimizes the effect of
the weathered layer on the
susceptibility measurement.
Data Accuracy
mode has distinct
IN
N
Uneven surfaces
With the sensor being in
direct contact to the surface, a
correction factor must be
applied to the readings.
The correction factor is based
upon the maximum elevation
difference of the peaks and
valleys of the sample surface
in the area being measured.
Some correction factors are:
1 mm = 1.07
5 mm = 1.41
10 mm = 1.96
The reading must always be
multiplied by the correction
factor, as the error always
results in too low of a reading.
Weathering
The largest influence is
directly at the face of the coil
and system sensitivity falls off
away from the coil face.
75
-P Mode
O IN