Observation of reduction of secondary electron emission from helium ion impact due to plasma-generated nanostructured tungsten fuzz

Hollmann, E. M.; Doerner, R.; Nishijima, D.; Pigarov, A. Yu.

doi:10.1088/1361-6463/aa8be3

Cited by 8 publications

(4 citation statements)

References 38 publications

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“…Recently, tungsten fuzz has generated interest due to its natural occurrence under tokamak disturbance-like conditions [20][21][22][23][24], which could allow for the sustained reduction of SEE (as opposed to conventional manufactured surfaces, where features gradually erode away). A similar reduction in the yield has also been measured for ion-induced SEE from tungsten fuzz [25].…”

Section: Introductionsupporting

confidence: 75%

Secondary electron emission from textured surfaces

Huerta¹,

Patino²,

Wirz³

2018

J. Phys. D: Appl. Phys.

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In this work, a Monte Carlo model is used to investigate electron induced secondary electron emission for varying effects of complex surfaces by using simple geometric constructs. Geometries used in the model include: vertical fibers for velvet-like surfaces, tapered pillars for carpet-like surfaces, and a cage-like configuration of interlaced horizontal and vertical fibers for nano-structured fuzz. The model accurately captures the secondary electron emission yield dependence on incidence angle. The model shows that unlike other structured surfaces previously studied, tungsten fuzz exhibits secondary electron emission yield that is independent of primary electron incidence angle, due to the prevalence of horizontally-oriented fibers in the fuzz geometry. This is confirmed with new data presented herein of the secondary electron emission yield of tungsten fuzz at incidence angles from 0–60°.

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Section: Introductionsupporting

confidence: 75%

Secondary electron emission from textured surfaces

Huerta¹,

Patino²,

Wirz³

2018

J. Phys. D: Appl. Phys.

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“…In addition to the exchange of kinetic energy, the internal state of the particles changed during the collision or transformed into other particles is called inelastic scattering. Inelastic scattering can be divided into single-electron excitation and plasma excitation [24][25][26][27]. Inelastic scattering is characterized by the energy loss function (ELF), in which the dielectric function reflects the response of the solid to external electromagnetic perturbations.…”

Section: Inelastic Scattering Propertiesmentioning

confidence: 99%

Modelling the Impact of Graphene Coating of Different Thicknesses on Polyimide Substrate on the Secondary Electron Yield

Qi,

Ma,

Liu

et al. 2023

Coatings

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Polyimide material is widely used in the aerospace field, but its secondary electron emission yield is high. In this study, a graphene coating was used to suppress its secondary electron emission, and the secondary electron emission yield of graphene-coated materials with different thicknesses was calculated using the GEANT4 numerical simulation method. The suppression effect of different thicknesses of graphene coatings on the secondary electron emission was analyzed. The simulation results showed that the optimal graphene coating thicknesses for the lowest secondary electron yield of polyimide materials were 1 nm and 5 nm, which reduced the secondary electron emission yield by 13% in terms of simulation. The 5 nm graphene coating reduced the secondary electron emission yield by 6% compared to the polyimide material from an experimental perspective. The 5 nm coating showed better results at higher energies and was experimentally verified by preparing five layers of graphene coating, which showed good agreement between the simulation and experiment. Meanwhile, with the increase in graphene coating thickness, the surface secondary electron emission displacement range decreased, and the secondary electrons produced at the surface were of low energy. The results of this study can provide technical reference for polyimide in aerospace applications and secondary electron emission simulation.

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“…The SEY is a surface property of the material and is strongly influenced by many factors [11,12], among which, surface adsorption is a significant one. It is well known, for example, that a metallic surface exposed to air has a much higher SEY than the corresponding clean metal [13,14].…”

Section: Introductionmentioning

confidence: 99%

Secondary electron yield of Cu (1 1 0) with adsorbed nitrogen: a 3D Monte Carlo simulation

Hu¹,

Xiao²,

Zhu³

et al. 2018

J. Phys. D: Appl. Phys.

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We developed an adsorption model to examine secondary electron (SE) emission from a surface adsorbed by N 2 molecules. In this model, the scattering processes of electrons and N 2 molecules are simulated by Monte Carlo method. The traces of both primary electrons (PEs) and SEs are tracked by combining the electron scattering in the material and adsorbed layer. The SE yield (SEY) is then calculated from the final states of electrons that can emit out from the adsorbed layers. Moreover, the effects of the work function variation induced by adsorption are also taken into account in the model. The SE emission properties of the surface under different pressures and surface coverage are examined by our adsorption model. We find that the SEY reaches its minimum for an intermediate coverage of 1 ~ 2 × 10 15 /cm 2 for the Cu substrate. Further investigations on returning and outgoing ratios and energy distributions of SEs indicate that an adsorbed layer can generate new electrons but weaken the electron energy, especially at a high PE energy. The competing mechanism of 'SE generation event' and 'energy losing event' controls the variation of SEY. Accordingly, our model could serve as a powerful tool and our results can provide comprehensive insight into the SE emission of the surface covered by gas molecules, thereby helping us to find a rationale for the behaviour of SEs under various surface conditions.

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Observation of reduction of secondary electron emission from helium ion impact due to plasma-generated nanostructured tungsten fuzz

Cited by 8 publications

References 38 publications

Secondary electron emission from textured surfaces

Secondary electron emission from textured surfaces

Modelling the Impact of Graphene Coating of Different Thicknesses on Polyimide Substrate on the Secondary Electron Yield

Secondary electron yield of Cu (1 1 0) with adsorbed nitrogen: a 3D Monte Carlo simulation

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