Tweet
I have found a lot of discussion on sensor for proton magnetometer. The most widespread opinion is that toroidal sensor is the best. The main advantage is its lack of sensitivity for rotation. In my opinion this is not so important. I live in the mid lattitude region (54N) and I have built several proton magnetometers, mainly for wreck hunting. My sensor is solenoidal. The main reason of such solution was minimal dimension perpendicular to the direction of towing. Signal ratio (as a function of direction of movement) is always lower than two. It is possible to compensate such low difference in signal amplitude with a bit higher gain in the main amplifier. My device has noise about 0.2 nT, for polarisation time 2 sec. Liquid volume is about 150 ml. Solenoid winding is divided (4 sections) for obtaining short time of field switch off. Digital part is composed mainly of CMOS logic of low scale of integration (4000 series). Power supply is accu 9 Ah. Its capacity is enough for 5 hours of work. I have worked a bit with toroidal sensor but I have abandoned this idea. It was too heavy and hard for refilling. Also winding was very time consuming in comparision with the solenoid.
Mike
Mike