Magnetoencephalogram systems developed at KIT

We have developed new systems for magnetoencephalography (MEG). The pick up coil is a coaxial type first-order gradiometer with 50-mm base line. The m agnetic field resolution of the system is about 4 fT/Hz(0.5) or 0.8 (fT/cm) /Hz(0.5) at white noise region. The unique feature of the system is the gan try-free horizontal dewar, which is fabricated through what we call a "ship -in-a-bottle approach". Less than 10-liter/day liquid helium consumption fo r the 100-liter capacity is realized. One of the merits of the horizontal d ewar is that a small room is sufficient for installation because of the low height (0.89 m) of the dewar. Another merit is that the patient can be mea sured in lying position which is more relaxing compared to the conventional vertical type.