Interaction of metastable helium atoms with a Mo [110] surface. Secondary electron spectroscopy

A source for a high-intensity pulsed beam of metastable helium atoms

“…The metastableatom flux is then given by j (He * ) = 4πr 2 nv H e . With the experimental values listed above we derive lower limits for the metastable-atom density in the interaction region of n(He * ) > 6×10 3 atoms mm −3 and for the flux of metastable atoms of j (He * ) > 4×10 15 atoms sr −1 s −1 . This corresponds to an efficiency of production of metastable atoms of about 10 −7 related to the flux of ground state helium atoms in the supersonic beam, which is lower than the efficiency typically obtained in set-ups with continuous low-density atomic beams [28].…”

“…We have presented the design and the performance of a pulsed gas discharge supported by injection of electrons as a stable and easy-to-operate source for a high-intensity beam of metastable helium atoms (flux > 4×10 15 atoms sr −1 s −1 ). Such a source will prove useful also when other species are used and is in particular a reliable tool for experiments which require a high pulsed flux of metastable helium atoms.…”

“…The internal energy is used, e.g. in reaction dynamics and collision induced processes [1][2][3][4][5][6][7][8][9][10][11], in surface analysis and lithography [12][13][14][15][16][17][18][19][20][21], in spectroscopy [22,23] and for the generation of radiation in the vacuum ultraviolet [24][25][26][27].…”

Probing the Local Density of States of Metal Surfaces by Deexcitation of Metastable Noble-Gas Atoms

“…7 FEBRUARY 1983 kinetic energy (-10 eV) of the ions involved. 2,4 This difficulty may be overcome by the use of electronically excited, metastable noble-gas atoms with thermal kinetic energy (<0.1 eV): The usefulness of this probe has already been recognized previously, 5 " 9 and the literature also contains reports on the deconvolution of recorded spectra 6,8 which were, however, at least partly questionable. In this Letter we describe what is believed to be the first reliable analysis of data obtained by this method and demonstrate what kind of information on the surface density of states (SDOS) can be obtained.…”