Multisensorial SQUID arrays

In the framework of the Piano di Potenziamento della Rete Scientifica e Tecnologica “Componentistica Avanzata” under the project Sviluppo di componentistica avanzata e sua applicazione a strumentazione biomedica, we have developed a multisensorial SQUID array for a large multichannel system for magnetoencephalography.

The sensor array has been designed in a helmet shape. The measurement plane consists of 154 SQUID-channels suitably distributed over a fiberglass surface to cover the whole scalp and to record effectively the magnetoencephalographic signals. Further 9 channels, installed on three bakelite towers (three triplet each having three orthogonal SQUID sensors), are used as references in order to detect background residual magnetic field far from the scalp (about 9 cm) and to subtract its contribution, via software properly implemented to this aim, from the brain signal detected on the measurement plane.

The  sensor  array,  as  shown  by  the figure,  is  inserted  in  a  fiberglass  Dewar with a helmet shaped bottom, at a distance of 18 mm from the outside, where the head of patient is housed. To avoid any damage the helmet has been surrounded by thin fiberglass shields.

The magnetoencephalographic system is working at diagnosis and treatment institute "Hermitage Capodimonte" in Naples (Italy).