ION-FOCUSED ELECTRON BEAM DIRECTIONAL MAGNETOMETER

摘要

Described is an electron beam magnetometer of the type adapted to detect disturbances in magnetic fields, particularly the magnetic field of the earth. This is accomplished by means of a space-charge-neutralized low voltage electron beam. Positive ions, obtained either by ion injection or weak ionization of a low pressure gas within an envelope through which the electron beam passes, hold the beam together along its path. The beam is normally centered by means of conventional horizontal and vertical deflection coils. Disturbances in a magnetic field traversing the beam cause it to deflect; and this deflection is sensed to indicate the disturbance.