SatisGeo PMG-2, User Manual

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3. DESCRIPTION OF THE INSTRUMENT
The proton magnetometer PMG2 consists of a processing unit, measuring
sensors, and a post.
3.1. Measuring Sensor With Accessories
The measuring sensor contains two coils properly arranged to suppress a
disturbing external field. The coils are placed in a laminated cylinder container filled with
a liquid rich in hydrocarbons.
North and south are marked on
the container of the sensor. The ‘north’ mark
should point to the geographical north. The orientation of the sensor does not affect the
value of the measured magnetic field, but it does affect the intensity of the signal from the
sensor and, thus, the size of the error of the measurement.
Figure 3.1 - Post assembly for line measurement.
For measurements, the sensor is mounted on a post which is assembled using up
to five half meter long sticks joined with screw coupling. In this way, the sensor can be
set to various heights above the ground
– see Figure 3.1. For gradient measurement, an
extension (gradient stick) is used to keep both sensors 0.5 or 1 m apart
– see Figure 3.2.
The gradient stick allows the position of the sensors to be set so that the orientation of
both sensors to the Earth´s magnetic field may be the same. For AUTO mode
measurements (diurnal variations), an anchor ring with ropes and pins is supplied to hold
the post in place.
The measuring sensors and the processing unit are connected via 2.5 m long
cables.