The atomic magnetometer: A new era in biomagnetism

The high cost and impracticality of SQUID (Superconducting QUantum Interference Device) magnetometers has limited the expansion of magnetoencephalography (MEG) and magnetocardiography (MCG), especially in countries where the cost of liquid helium is high. A recent breakthrough, however, has the potential to radically change this situation. In 2003, a group at Princeton University demonstrated an atomic magnetometer, known as the SERF (spin-exchange free relaxation) magnetometer, with unprecedented sensitivity. Since then, several research groups have utilized SERF magnetometers to record MEG, MCG, and fetal MCG signals. Despite some modest drawbacks, it now seems almost certain that SERF magnetometers can replace SQUIDs for many applications. With a price tag that is likely to be far less than that of SQUIDs, SERF magnetometers can propel the next wave of growth in biomagnetism.