| 摘要 |
PURPOSE:To increase the brightness as observed from the mass spectrometer of an FAB ion source by arranging a mesh or a lattice stuck with a sample in parallel with an ion acceleration electrode and radiating a neutral atom beam to the sample from behind the mesh or the lattice. CONSTITUTION:A neutral atom beam A coincides with the center line of an ion acceleration electrode 4, and the face of a mesh 5 is at a right angle to this neutral atom beam A. An orifice and a repeller electrode 6 are at the same potential and are set to the same potential as that of the mesh 5 or a potential slightly higher than that (in case of positive ions). The neutral atom beam A passes the center hole of the repeller electrode 6 and hits the mesh 5. The mesh 5 is arranged in parallel with and near the ion acceleration electrode 4, the equipotential surface U with a potential lower than that of the mesh 5 (in case of positive ions) penetrates between wires of the mesh 5, and on the other hand, there is the repeller electrode 6 in the back, thereby nearly all the sample molecule ions sprung out through the wires of the mesh 5 are extracted toward the acceleration electrode 4. |
