Bombardment, ion

Once a sample is properly oriented and polished, it is placed into a UHV chamber for the final preparation steps. Samples are processed in situ by a variety of methods in order to produce an atomically clean and flat surface. Ion bombardment and aimealing (IBA) is the most conunon method used. Other methods include cleaving and film growth. 

Dodonoy A I, Mashkova E S and Molchanov V A 1989 Medium-energy ion scattering by solid surfaces. Ill ejection of fast recoil atoms from solids under ion bombardment Rad. Eff. Def Sol. 110 227-341... 

Figure C2.18.3. Relationship between ion-assisted etching and directionality in plasma etching, (a) Demonstration of the synergy between ion bombardment and reactive species during ion-assisted etching, (b) Ions incident on an etched feature. This situation prevails in glow discharges when the feature dimensions are much less than the plasma sheath thickness. Reproduced from [35]...

Vitkavage D J, Dale C J, Chu W K, Finstad T G and Mayer T M 1986 Ion channeling studies of low energy ion bombardment induced crystal damage in silicon Nucl. Instrum. Methods B 13 313-18... 

Abrams C F and Graves D B 1998 Energetic Ion bombardment of SIOj surfaces molecular dynamics simulations J. Vac. Sc/. Technol. A 16 3006-19... 

To achieve sufficient vapor pressure for El and Cl, a nonvolatile liquid will have to be heated strongly, but this heating may lead to its thermal degradation. If thermal instability is a problem, then inlet/ionization systems need to be considered, since these do not require prevolatilization of the sample before mass spectrometric analysis. This problem has led to the development of inlet/ionization systems that can operate at atmospheric pressure and ambient temperatures. Successive developments have led to the introduction of techniques such as fast-atom bombardment (FAB), fast-ion bombardment (FIB), dynamic FAB, thermospray, plasmaspray, electrospray, and APCI. Only the last two techniques are in common use. Further aspects of liquids in their role as solvents for samples are considered below. 

The impact of a primary beam of fast atoms or ions on a target matrix (substrate and solvent) causes desorption of molecular or quasi-molecular ions characteristic of the substrate. The process is called FAB for atom bombardment or LSIMS for ion bombardment. 

Although there has been theoretical and experimental interest in the effects of ion bombardment on materials since about 1960 (153), the growth in ion implantation technology and appHcations since then is due almost solely to the semiconductor (integrated circuit) industry. The advantages of ion implantation for semiconductor doping were first pointed out in 1955 (154), but these advantages were not widely accepted until about 1970. 

O. AucieUo and R. KeUy, eds.. Ion Bombardment Modfication of Suf aces Fundamentals and Applications, Elsevier, Amsterdam, 1984. 

Plant capacity is a function of feed size distribution and Hberation. Separators can accept a size range as wide as 50—1000 p.m. Capacities are typically 1000 2500 kg/(h-m) based on rotor length which could be up to 3 m and have dia 150—250 mm. The feed should be as dry as possible because moisture interferes seriously with separation. Heaters are usually provided before the feed enters the charged field. Final cleaning is often conducted in electrostatic-type separators. Electrostatic shape separation, a newer form of ion bombardment separation, involves separation of particles based on shape and density without consideration to conductivities (37). 

The head of the femoral component then articulates with an ion-bombarded, HDPE, high walled, acetabular liner which fits iato a screwed ia, machined, titanium, chromium—cobalt—molybdenum or vanadium—aluminum metallic alloy hydroxyapatite-coated acetabular shell/cup. Each of the separate parts of the modular system for total hip arthroplasty is manufactured ia several different sizes. 

Ion Bombardment fFig. 19-55c) The most positive and strongest method of charging particles for electrostatic separation is ion bombardment. Use of ion bombardment in charging materials of... 

The common types of other industrial electrostatic separators employ charging bv conductive induction anchor ion bombardment. Figure 19-56 illustrates the principles of application,... 

Charging bv ion bombardment is the technique used in most mineral separations. The conductive-induction (nonionizing) plate types of separators have also been used Application.s of this device in the minerals indiisti v include its use as a final cleaning step when concentrating rutile and zircon,... 

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