Instrument Details 
Name: Spinner Magnetometer – JR6, Made: AGICO, Czech Republic 

Specifications: 
Cylinder Specimen Size : 25.4 mm / 22 mm, Cubical Specimen Size : 20 mm on edge, 
Sensitivity : 2.4 x µA/m, Noise : 2.4 x µA/m, Accuracy : 1%, ± µA/m, Rotation Speed : High:  87.7 rps, Low:   16.7 rps, Measuring Ranges : up to 12,500 A/m, Power : 110 V / 60 Hz or 220 V / 50 Hz

Principle 
Rock specimens of defined size and shape rotates at a constant angular speed in the pick-up unit inside a pair of coils. An AC voltage is induced in the coils whose amplitude and phase depend on the magnitude and direction of the RM vector of the specimen. The voltage is amplified, filtered and digitized. By Fourier analysis the computer calculates two rectangular components of the projection of RM vector into the plane perpendicular to the axis of rotation.

Applications 
This instrument is used in palaeomagnetic applications, to measure Natural Remanent Magnetization (NRM) of the rock specimens with high precision. This instruments enable measurement of even very weakly magnetic sedimentary rocks including limestone.