Three component spinner magnetometer featuring rapid measurement times

We describe the fabrication and performance of a spinning rock magnetometer for measuring the intensity and direction of the remanent magnetisation of rock specimens collected in palaeomagnetic surveys. The strength of these fields is measured using a high temperature superconductor (HTS) rf SQUID. Samples are rotated around two orthogonal axes to facilitate the calculation of the three-component remanence vector with a minimum of operator intervention. Measurements of remanence values ranging from 10¹ to 10^-5 A/m, with errors of 1×10^-5 A/m, have been achieved in measurement times of 20 s, while operating the instrument in a typical geophysical laboratory environment. In this paper we discuss the design requirements and data processing necessary to achieve a user-friendly system