The measurement setup in the shielded MEG room

The Weakest Magnetic Field Ever Measured

October 10, 2013

Here's one for the record books: The Martinos Center’s Sheraz Khan and David Cohen have reported the weakest magnetic field measured. This qualifies them for the Guinness Book of World Records.

The measurement was to determine the magnetic field of the wall in the magnetically shielded MEG room at the Martinos Center; MEG is used to map brain activity in the brain. Here, in order to measure the magnetic fields generated by the brain, researchers must account for the influence of other magnetic sources – in this case, the wall of the room housing the technology. The magnetic field of the wall? 0.5 femtotesla/√Hz, the weakest ever measured.

Khan and Cohen published the findings in the Review of Scientific Instruments in May of this year.