Modification of optical characteristics of metallic amorphous mirrors under ion bombardment

Abstract

In-vessel mirrors are necessary for optical diagnostics of plasmas in next-step fusion devices. These mirrors will be under the influence of the harsh fusion environment, and in these conditions the mirror material should perform its functions. This article describes experiments that have been carried out to evaluate the prospect of amorphous mirrors retaining their optical characteristics under the impact of deuterium or argon plasma ions of different energy. The experiments were undertaken with the use of mirror samples prepared from amorphous alloys Vitreloy-1 and Vitreloy-4. The data reported demonstrate the principal ability of mirrors made of amorphous materials to preserve the initial optical quality in the process of long-term sputtering, and should be considered as proof of the possibility of using amorphous metal mirrors in the erosion-dominated zone of a fusion reactor.

Development of surface relief on polycrystalline metals due to sputtering

“…After crystallization by annealing at 773 K for 1 h, the position of the peaks in a diffractogram indicated the existence of the following nanocrystals: Zr 2 Ni, Ti 2 Ni, Zr 2 Cu, and Zr x Cu y with x and y exceeding two. For the amorphous mirrors, Ar + sputtering to an averaged sputter depth of 13.4 μm was found to have little impact on the optical characteristics [6]. However, the optical properties of the crystallized mirrors were found to degrade very rapidly by sputtering.…”

“…A comparison of sputtering behavior and optical characteristics of amorphous and crystallized mirror specimens fabricated by annealing from an amorphous alloy with composition Zr(41.2%)Ti(13.8%)Cu(12.5%)Ni(10%)Be(22.5%), in atomic percents, was presented in [6]. After crystallization by annealing at 773 K for 1 h, the position of the peaks in a diffractogram indicated the existence of the following nanocrystals: Zr 2 Ni, Ti 2 Ni, Zr 2 Cu, and Zr x Cu y with x and y exceeding two.…”

“…In the present paper, we compile and analyze the results of some of our experiments on this subject (in [5][6][7] and some new data) and make comparisons with numerical simulations of surface roughness development on polycrystalline materials with single-or multi-sized grains having randomly distributed crystal orientation.…”

Role of Recrystallization of Tungsten in Formation of a Roughness of Its Surface Under Influence of Successive Action of Neutrons and Sputtering

“…7), означают, что эллипсомет-рия «не видит» ту шероховатость, которая хорошо видна на микро-фотографиях, и которая даёт рассеяние и, соответственно, падение отражения. Этот эффект нами ранее обсуждался и связан с принци-пиальным различием физических процессов, лежащих в основе этих двух методик [18,19]. Этот результат означает, что на поверх-ности формируются шероховатые структуры двух масштабов -микро-и наношероховатость (см.…”

“…Можно заметить резкий сдвиг интер-ференционных полос на границах некоторых зёрен (отмечен стрел-ками на рис. 8, в, г), что свидетельствует о развитии ступенчатой структуры поверхности и типично для поликристаллических мате-риалов, подвергающихся длительному распылению [18,19]. Дан-ные изменения одинаковы для обеих сторон образца (необлучённая сторона (рис.…”