Thursday, September 18, 2014, 16:00
WHGA/Auditorium
Georg Bison, PSI
Abstract:
Atomic magnetometers use the precession of atomic spins to accomplish highly sensitive measurements of magnetic fields. The atoms are spin polarized using optical pumping with laser light. The same light is also used to detect the spin precession frequency which is proportional to the modulus of the magnetic field. Such magnetometers can detect magnetic field changes of a few fT, nine orders of magnitude smaller than the earth’s magnetic field. This high magnetic field resolution is needed for fundamental physics experiments that require precise magnetic field control, such as the neutron EDM experiment at PSI.
A different application of the same sensors is the detection of magnetic fields generated by the electrophysiological processes in the human body. Especially biomagnetic signals from the heart (magnetocardiography, MCG) and brain (magnetoencephalography, MEG) are studied in order to gain information about the complex processes that control our bodies. Arrays of sensitive magnetometers provide a map of the magnetic field which can be used to localize biomagnetic sources. In this way bio-magnetometer systems provide images of heart or brain activity in a non-invasive way.