Magnetic valley is a project aiming at the development of operational products and services, based on the expertise of the RMI Geophysical Centre, in order to contribute to the socio-economic revival. For more than 50 years, the fields of expertise in which the Geophysical Centre is a world reference are: the Earth's magnetic field, the ionosphere and the environmental magnetism.
Autodif makes it possible to automate completely the absolute measurements of the geomagnetic field declination and inclination. Automation without disturbing observations has been a real challenge to overcome since many key elements like sensors, motors or electronics generally contain ferromagnetic elements and conduct electrical currents.
The geomagnetic observatory community needs nonmagnetic theodolites equipped with a fluxgate (a so-called DIflux or DIM) in order to accurately measure the orientation of the geomagnetic field vector.
Magnetic Valley is proud to announce the innovative WIDIF and FLM4 DIflux instruments based on the BOIF TDJ6E-NM nonmagnetic theodolites manufactured in China and equipped with our an in-house electronics console. Two versions of the DIflux are proposed:
The WIDIF (Figure 1) where the console is mounted on the telescope. This results in a very compact instrument adressing the needs of the surveyor in the field.
The FLM4 (Figure 2) which has its console linked by wire to the fluxgate and theodolite. The FLM4 has been designed for highly accurate measurements in an observatory environment.
The electronic console contains the magnetometer electronics for reading the fluxgate output but not only:
- a GNSS receiver provides precise timing worldwide and latitude/longitude,
- a sunshot computer gives the azimuth of the Sun to the nearest arcsecond for the time and coordinates observed in situ (see figure 3),
- a data logger can transform the DIflux in a recording variometer,
- power is provided by a nonmagnetic lithium-polymer battery.
We are offering currently measurements of
- magnetic properties (e.g. susceptibility, remanent magnetisation, hysteresis)
- non-magnetic properties (e.g. volume, density, porosity, dry matter)
Archaeomagnetic dating is based on our current knowledge of the secular variation of the geomagnetic field in the past and on the property of baked and burned materials such as baked clays, carried at high temperatures, to acquire during their cooling a stable remanent magnetisation called thermoremanent magnetisation. For isotropic and homogeneous materials, the direction of this magnetisation is parallel to the ambient geomagnetic field and its intensity is proportional to the field intensity.