Abstract:
A tri-axial square Helmholtz coil system for the
study of palaeomagnetic studies, manufactured by GEOFYZIKA
(former Czechoslovakia), was successfully commissioned
at the Alibag Magnetic Observatory (IAGA code:
ABG) in the year 1985. This system was used for a few years,
after which the system encountered technical problems with
the control unit. Rectification of the unit could not be undertaken,
as the information document related to this system
was not available, and as a result the system had been lying
in an unused state for a long time, until 2015, when the
system was recommissioned and upgraded to a test facility
for calibrating the magnetometer sensors. We have upgraded
the system with a constant current source and a data-logging
unit. Both of these units have been designed and developed
in the institute laboratory. Also, re-measurements of the existing
system have been made thoroughly. The upgraded system
is semi-automatic, enabling non-specialists to operate it
after a brief period of instruction. This facility is now widely
used at the parent institute and external institutions to calibrate
magnetometers and it also serves as a national facility.
Here the design of this system with the calibration results for
the space-borne fluxgate magnetometers is presented.
