Sputtering of Mo and Al in D2/N2 plasma cleaning discharge. (August 2017)

• Record Type: Journal Article
• Authors: Bukhovets, V.L.; Gorodetsky, A.E.; Zalavutdinov, R.Kh.; Markin, A.V.; Kazansky, L.P.; Arkhipushkin, I.A.; Zakharov, A.P.; Dmitriev, A.M.; Razdobarin, A.G.; Mukhin, E.E.
• Is Part Of: Nuclear materials and energy. Volume 12(2017)
• Page Start: 458
• Page End: 461
• Publication Date: 2017-08
• Subjects: Nuclear energy -- Periodicals; Nuclear fuels -- Periodicals; Nuclear reactors -- Materials -- Periodicals; Radioactive substances -- Periodicals; 621.4833
• DOI: 10.1016/j.nme.2017.05.002
• Languages: English
• ISSNs: 2352-1791

Abstract

Highlights: The N2 addition of the D2 plasma accompanied by the synthesis of ND3 . The sputtering rate of Al and Mo increased with the N2 fraction up to 15%. The Be sputtering rate was practically unchanged. A further increase in N2 fraction led to a decrease in metal sputtering rate. Plasma cleaning of Mo mirrors don't cause the deterioration of optical properties. Abstract: Sputtering of Mo and Al (as Be proxy) in mixed D2 /N2 DC glow discharge was studied in view of the first mirror performance. The composition of the working gas was varied from 100% D2 to 100% N2, while keeping a total pressure of 15 Pa. The ion energies striking the sample surface were defined by its 100 V biasing negative to a floating potential. It has been obtained that the sputtering yield of Mo and Al increases gradually with N2 concentration up to 4‒16 mol% and decreases with further N2 addition. In contrast, the sputtering yield of Be remains unchanged up to 10 mol% of N2 . Adding 16 mol% leads to three-fold decrease in the sputtering rate. The sputtering behavior is discussed in context of surface data analysis and mass spectroscopy of the discharge gas exhaust. Variation in reflectivity of a single crystalline Mo due to plasma exposure under similar conditions is also presented and discussed.