Time-of-flight analyzer system to detect reflected particles from a solid surface following low-energy particle injection

Abstract

We have developed a time-of-flight analyzer to measure energy distributions of reflected particles from solid surfaces bombarded by low-energy (1–2keV) ions. The analyzer yields energy distributions of neutrals which can be compared with the energy distributions of charged particles measured by a magnetic deflection-type momentum analyzer. We have tested the system to measure the angular dependence of energy and intensity for neutrals reflected from a polycrystalline W target. The energies of the reflected neutrals are much smaller than the incident ion energies, suggesting multiple scattering in the target. No angular dependence is observed under the condition that the sum of the incident and reflected angles is constant. The intensity of the reflected neutrals takes the maximum around the mirror angle. We compare these characteristics of neutral particle reflections with those of reflected ions.

Low-energy particle interaction at carbon nanowalls on W surface

“…The energies of reflected particles were smaller than those of the incident particles, due to the energy losses by multiple scattering inside the target surface layer. This trend is very similar to the ones reported for polycrystalline metal samples [13,14]. The dependence of the particle energy and intensity upon the incident angle is shown in Fig.…”

“…We employed two fixed TOFA systems as shown in Fig. 2(a): 0°-TOFA along with the axis of the incident beam for the time calibration and 45°-TOFA aligned at 45°with respect to the incident beam [14]. The TOFA may detect the neutrals of down to a few hundreds eV.…”

“…The details of the experimental system were reported elsewhere [13,14]. The analyzer angle against the incident beam was calibrated by directly injecting the weak primary beam from the ion source to the analyzer.…”

“…We have been developing an experimental system for studying fundamental processes of the particle interactions with solid surfaces [9][10][11][12][13][14]. This system successfully yielded data on reflected ions and neutrals from polycrystalline metal surfaces (Mo, C, W, V-alloy) following low-energy (1-3 keV) beam injections.…”

“…The angular distributions and energy spectra of positive and negative ions reflected from the materials were measured by a magnetic momentum analyzer (MMA) [11][12][13]. Recently, we added a timeof-flight analyzer (TOFA) to the existing MMA so we could make complementary measurements of neutral particles during ion bombardment [14]. In this paper we report the experimental results of using the MMA-TOFA system to measure low-energy particle injection onto a carbon nanowall (CNW) coated W surface.…”