Un sistema automatico per la misura di tre componenti del campo geomagnetico utilizzante un magnetometro a precessione nucleare

Recording in digital form from the start is almost a necessary step in<br />Geomagnetic Observatories; we propose in this paper a simple method<br />based on the use of a proton precession magnetometer equipped with two<br />Helmholtz coils. A small microprocessor has been used to transform<br />the signal frequency measured by the electronic counter to obtain the<br />components absolute values and to automatize the set of measures.<br />A sophisticated equipment for the current generation and control was<br />necessary to maintain the current flowing in the Helmoholtz coils within<br />2 [iA for successive measurements. To maximize the signal coming from<br />the sensor inside the coils, for the different components, a simple arrangement<br />of two ortogonal small coils in only one sensor has been made.<br />The system proposed can furnish a very good stability and accuracy<br />(~ 1.5 riT) in the measured components (H, D, Z) and could avoid the<br />absolute measurements.<br />The time sampling for the complete set of components is ~ 20 sec;<br />the instrument can be used then to obtain informations of the geomagnetic<br />variations with period T > 1 min. The Observatory use is<br />suggested for an automatic hourly means computation.

Abstract licence: CC BY

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