Development of an angular-resolved momentum analyzer system to study particle reflections from solid surfaces

Abstract

An experimental system designed to study systematically interactions of beams with solid surface is being developed. A small magnetic multicusp-type ion source is used to produce both positive and negative ions with a pair of removable filter magnets. The mass-separated extracted ions are then directed onto a solid target, and the angular distributions and energy spectra of the reflected ions are measured with a magnetic momentum analyzer. The performance of the system is tested by investigating the particle reflections from a polycrystalline W surface bombarded by low-energy (1–2 keV) H and O ions.

Particle reflections of low energy light ions from a vanadium alloy (V–4Cr–4Ti)

“…1 shows examples of the energy and angular resolved intensity contour map of H + and H À ions at the incident angle of 20°at room temperature, reflected from (a) Mo, (b) carbon on Mo, (c) W and (d) Vanadium alloy targets, respectively. We observe similar trends for all targets [5,6]. We always observe the positive and negative ion reflections for both cases of the positive and negative hydrogen ion injections.…”

“…When the oxygen beam was injected onto the vanadium alloy, we observed the reflected ion intensity only in the negative ion side and there were no positive ions, while very weak O + ions were observed from a W target [6]. Compared with the cases of Mo and W targets, energies at which the energy distributions of reflected ions from vanadium take their maxima show stronger angle dependence for both cases of hydrogen and oxygen beam injections.…”

“…In the H + beam injection the intensities of the reflected positive ions are usually higher than those of the negative ions in this energy range. The normalized intensities of the reflected ions for the vanadium target are the same order as those for W and Mo [5,6]. The energy spectra of the reflected ions from the vanadium target depend upon the reflection angle b more strongly than other targets.…”

“…The detail of the experimental system has already been reported elsewhere [5,6]. Several improvements have been made to study hydrogen-absorbing characteristic of vanadium alloys.…”

“…The system has successfully produced ion spectra reflected from Mo, carbon coated Mo, and W targets [3][4][5][6]. In this paper we report the first results of the study on particle reflections from the NIFSHEATs vanadium alloy bombarded by low energy (1-2 keV) hydrogen ions.…”