BARTINGTON INSTRUMENTS
Page 30 of 61 OM1800/26
The number of lines of data recorded will be determined by the size of the Grid and the line
spacing selected as
lines/m
. For the Grad601-1 single sensor gradiometer, one line of data will
be recorded for each traverse. For the Grad601-2 dual sensor gradiometer, two lines of data will
be recorded for each traverse. The traverse number is displayed during the survey.
Values of the magnetic gradient will be recorded at a series of positions along each traverse. The
number of samples per metre, selected in the
Set parameters
menu, determines the number of
positions and is set by the operator at 1, 2, 4 or 8 samples per metre. The readings will start at
Position 1.
Traverses are walked in either parallel pattern (Figure 10), where each traverse starts at the
same side of the Grid, or zigzag pattern (Figure 11), where traverses start at alternate sides of
the Grid. A zigzag pattern is normally used to minimise the distance walked.
17.2. Single and Multiple Sensors
The sensors of the Grad601-2 dual sensor gradiometer are arranged to the left and right of the
operator with a fixed separation of 1m. The operator therefore walks between two data lines
recorded during each traverse. The
Trav
(traverse) number will correspond to two lines of data
recorded simultaneously.
When using a single sensor gradiometer, the
Trav
(traverse) number shown in the display will
correspond to the data line number.
The number of data lines per metre required is set in the
Set parameters
menu. Therefore, if data
is required at a density of one line per metre with a dual sensor gradiometer, then the operator
Figure 11: Zigzag traverse pattern.
