Patent ID: 7180060

Claim:
An ion detector, comprising: a planar electrically conducting entrance plate, having an entrance window therein, said entrance window comprising a first transparent mesh; a converter assembly comprising a planar electrically conducting converter plate and a converter member for providing free electrons upon impact of ions, said converter member being supported by said converter plate; a planar electrically conducting exit plate, having an exit window therein; a magnet assembly for providing a homogeneous magnetic field in the space between the converter plate and the exit plate, respectively, and the entrance plate; and an electron detection assembly for detecting the electrons passing through said exit window, wherein: the planes of the exit plate the converter plate and the entrance plate are parallel, the converter plate and the exit plate are facing the entrance plate, such that the converter member is aligned with the entrance window, further the converter plate, the converter member and the exit plate are electrically biasable with respect to the entrance plate, in order to provide a homogeneous electric field between the converter plate and the exit plate, respectively and the entrance plate, the magnetic field extends parallel to the plane of the converter plate, and the ratio between the electric field and the magnetic field is such that the electrons emitted from the converter plate are traveling to the exit window.