 SQUID magnetometers require cooling with liquid helium () or liquid nitrogen () to operate, hence the packaging requirements to use them are rather stringent both from a thermal-mechanical as well as magnetic standpoint.SQUID magnetometers are most commonly used to measure the magnetic fields produced by laboratory samples, also for brain or heart activity (magnetoencephalography and magnetocardiography, respectively).Geophysical surveys use SQUIDs from time to time, but the logistics of cooling the SQUID are much more complicated than other magnetometers that operate at room temperature.