Question What are the differences between the standard MFAM and the SX version?

The only difference between the standard and SX version is the sensitivity is 4pT/rt-Hz and 20 pT/rt-Hz respectively.

Here is an expected response with the magnetometer moving past a generic magnetic projectile:

In this case the amplitude is about 1nT in total from peak to peak. The feature itself is quite distinguishable. This is assuming there is no noise in the system.

Here is what the data looks like with 4pT/rt-Hz noise:

You can see the general structure is still there but there is a little more wiggle on the trace that is associated with the noise of the system.

Here is the data with 20 pT/rt-Hz noise:

Again, here the structure is clearly visible but the data looks a bit noisier. With some signal processing technique, such as low pass filtering, noises can be further reduced.  Please note that in real surveys, detecting 1nT peak-peak anomalies is always a big challenge even with the most sensitive magnetometers due to other noise sources, such as motion noises and environmental noises. Therefore, SX version is in general NOT the limiting factor for conducting surveys.

To understand this concept better, you can use the magnetic gradient tool developed by our partner in the UK, Geomatrix Earth Science.