초록 ▼

An apparatus for generating and transporting a charged particle beam. The apparatus has a source which generates the charged particle beam at two current levels, and a magnet system for bending the beam. Particles of different energies are bent along different paths, whereby at a specific height wit

An apparatus for generating and transporting a charged particle beam. The apparatus has a source which generates the charged particle beam at two current levels, and a magnet system for bending the beam. Particles of different energies are bent along different paths, whereby at a specific height within the magnet system the radial displacement from the beam axis is a monotone function of the difference between the energy and the nominal energy. At this height there is provided an energy selection filter having at least one bimetallic element. This element projects into the beam and, thus, intercepts beam particles; it is designed such that its interception distance decreases with increasing beam current. As a result, the energy range of particles passing the filter is broader at the higher current level broader than at the lower current level.

대표청구항 ▼

An apparatus for generating and transporting a beam of charged particles, comprising: (a) a beam source for generating said beam of charged particles at two different current levels, said charged particles being energetically dispersed around a preset energy value; (b) a magnet system for transporti

An apparatus for generating and transporting a beam of charged particles, comprising: (a) a beam source for generating said beam of charged particles at two different current levels, said charged particles being energetically dispersed around a preset energy value; (b) a magnet system for transporting said beam of charged particles through a passageway, said charged particles being spatially dispersed around a beam axis such that along a selected direction in a specific plane across the beam axis the spatial dispersion of said charged particles is at least approximately a monotone function of their energy dispersion; and (c) an energy selection filter disposed in said specific plane within the passageway, said filter including a first bimetallic element projecting along said selected direction into the beam by a given interception distance which defines the energy range of the charged particles passing the electron selection filter, said bimetallic element being adapted such that at the lower of the two different current levels the interception distance is longer and thereby said energy range smaller than at the higher of the two current levels.