Installation of an Electromagnetic Test Facility in Hungary

Electromagnetically clean room is planned to be built in the Széchenyi István Geophysical Observatory in western Hungary. The environmental magnetic field will be reduced by five order of magnitude, which is well below the interplanetary magnetic field near the Earth. One of the application of the laboratory is to support magnetic cleanliness program for space equipments. Moreover, in particular for space applications, it is planned to develop, test and calibrate a new generation of magnetometers called SERF (Spin Exchange Relaxation-Free). Active compensation of the terrestrial field will be achieved by means of large coils with current determined from the actual field, which is measured through a magnetometer placed in the observatory. Passive shielding will be provided by a cube shaped room covered with two layers of mumetal. The novelty of the facility is that the two shielding techniques will be harmonized. To this purpose, detailed model calculations were performed in order to determine the best setup for the coils. The results of the numerical calculations show that the size of the compensating coils should be much larger than the size of the room covered with mumetal layers.