ION BEAM GENERATING METHOD AND ELECTRON FIELD IONIZATION TYPE GAS PHASE ION SOURCE

摘要

PURPOSE: To provide an ion beam generating method capable of cleaning the surface of an emitter in a relatively low evaporating electron field and to provide an electron field ionization type gas phase ion source. ;CONSTITUTION: A control circuit 14 monitors the temperature at the tip of a cryostat 3 (actually, temperature of an emitter 1), and controls a heater controller 11 to maintain the temperature of 100K. When the temperature of the emitter 1 becomes 100K, the control circuit 14 controls a drawing-out voltage power source 7, and voltage V1 for electric field evaporating the emitter 1 is applied across the emitter 1 and a drawing-out electrode 5. After electric field evaporation operation was conducted for several seconds, the control circuit 14 controls the heater controller 11 to stop heating current supplied to a heater 10. The emitter 1 is gradually cooled. After confirming that the temperature of the emitter 1 decreased to 10K, the drawing-out voltage power source 7 is controlled, and drawing-out voltage is applied so that an angular current density of 1-2μA/sr is obtained between the emitter 1 and the drawing- out electrode 5.;COPYRIGHT: (C)1995,JPO