Method and apparatus for producing a monatomic beam of ground- state atoms

摘要

A specimen of molecules containing the desired element is contained in a low-pressure environment and is exposed to a beam of electrons of predetermined energy, causing the electrons to be captured by the molecules. The reaction is chosen so that there is a natural dissociation into an ion containing the desired element. The reaction region is subjected to an electrical field that accelerates the ions and removes them from the reaction region, at which time the ions are exposed to a laser beam of a wavelength sufficient to photodetach a substantial number of electrons from the ions, producing neutral atoms of the desired element. The entire particle stream exiting the interaction region is subjected to a magnetic field that bends the charged ions away from the neutral atoms so that the neutral atoms can then be directed to a test specimen or collection device, as the case may be. The apparatus for carrying out the method includes a pressure vessel for maintaining the environment in which the reactions take place at a pressure in the neighborhood of 10.sup.-4 Torr and, typically, the same magnetic field that is used to separate the ions from the neutral atoms is also used to collimate the electron beam for better localization, to interact with the molecules.