Collisions of low-energy Ar+, N-2(+), and D-2(+) ions with room-temperature and heated surfaces of mixed beryllium-tungsten thin films of different composition

0506908 - ÚFCH JH 2020 RIV NL eng J - Journal Article
Harnisch, M. - Keim, A. - Scheier, P. - Herman, Zdeněk
Collisions of low-energy Ar+, N-2(+), and D-2(+) ions with room-temperature and heated surfaces of mixed beryllium-tungsten thin films of different composition.
International Journal of Mass Spectrometry. Roč. 365, MAY 2014 (2014), s. 316-323. ISSN 1387-3806. E-ISSN 1873-2798
Institutional support: RVO:61388955
Keywords : polyatomic ions * metals * Ion surface collisions, Mass spectra of product ions * Mixed film Be-W surfaces * Ar+, N-2(+), D-2(+) projectiles
OECD category: Physical chemistry
Impact factor: 1.972, year: 2014
Method of publishing: Limited access

Collisions of Ar+, N-2(+), and D-2(+) ions of incident energies 20-100 eV with thin mixed beryllium-tungsten films of different composition (BeW(90:10), BeW(50:50), BeWO(60:22:11)) and different temperatures of the samples (room temperature, 150 degrees C, 300 degrees C) were investigated using a tandem mass spectrometer system. Mass spectra of product ions arising from Ar+ collisions with the three samples showed sputtering of the basic material of the sample substrate (Be+, BeH+, BeOH+, Li+, Na+, K+) and of hydrocarbon ions from the hydrocarbon coverage of the sample that decreased with increasing temperature. Sputtering of W+ or its compounds could not be detected. Normalized relative ion yields of Be+ and its compounds were not proportional to the Be content in the sample. Mass spectra from N-2(+) collisions were very similar to those of Ar+. Surface-induced dissociation of N-2(+) to N+ was not detected. The most conspicuous difference between mass spectra from D-2(+) impact and from Ar+ impact was a much lower sputtering efficiency of D-2(+) (by a factor of 50-100 or, for alkali ions, even more). The relative ion yield of Be+ strongly increased when the temperature of the sample was raised to 400 degrees C and 450 degrees C. A surface chemical reaction between the incident D-2(+) and surface Be leading to BeD+ was observed. The data may be of interest as basic information relevant to plasma-wall interactions in fusion devices. (C) 2014 Elsevier B.V. All rights reserved.
Permanent Link: http://hdl.handle.net/11104/0298044