Pulsed electron beam deposition

Pulsed electron beam deposition (PED) Pulsed electron beam source emitting 100 ns long electron pulses with 10-20 keV and kA intensity into the deposition chamber, no excimer laser is required, innovative complimentary technique to PLD, further extending the range of materials to be grown as thin films by pulsed energy techniques [128,135]... 

Other coating processes involving fluoridated apatite have been investigated to improve the long-term adhesion and promote osteointegration of cementless titanium-based metal implants pulsed laser deposition, electron beam deposition and ion beam sputter deposition techniques, and sol-gel methods, for example. They lead to fluor-containing calcium phosphates (apatites in most cases) with different compositions and crystallinity states. 

A series of pulsed electron beam tests were conducted on dextrinated and RD-1333 Pb azide pellets by Avrami et al (Ref 232), From the limited data in Table 14 it can be seen that sample ambient pressure, sample thickness and type of Pb azide are all important factors in the sensitivity of initiation by pulsed electron beam The question arises as to what mechanism can explain the observed pressure, thickness and type of Pb azide dependence. A purely thermal initiation mechanism or a compressive shock initiation resulting from nearly instantaneous energy deposition can account for some of the observations but not all... 

Fig. 1. Optical absorption spectra for various a-Si films ar.d laser treatments. E440 represents the absorption coefficient for electron-beam-deposited a-Si at 440°C substrate temperature, whereas LA and LC represent the laser-annealed and laser-crystallized spectra, respectively. The absorptivity curve of the CVD film is from Janai and Moser (1982) after pulse crystallization the curve PLA was measured.

Energy deposited from irradiation by a pulsed electron beam in 7-22 nm Si02 particles crosses the solid-liquid interface and appears as solvated electrons in the aqueous phase. 

Liu Z, Gao W, Dahm K L, Wang F, The effect of coating grain size on the selective oxidation hehaviour of Ni-Cr-Al alloy , Scripta Mater, 37 (1997) 1551-1558 Strauss D, Muller G, Schumacher G, Engelko V, Stamm W, Clemens D, Quadakkers W J, Oxide scale growth on MCrAlY bond coatings after pulsed electron beam treatment and deposition of EBPVD-TBC , Surf Coat Technol, 2001, 135(2—3), 196-201... 

Much of the energy deposited in a sample by a laser pulse or beam ablates as neutral material and not ions. Ordinarily, the neutral substances are simply pumped away, and the ions are analyzed by the mass spectrometer. To increase the number of ions formed, there is often a second ion source to produce ions from the neutral materials, thereby enhancing the total ion yield. This secondary or additional mode of ionization can be effected by electrons (electron ionization, El), reagent gases (chemical ionization. Cl), a plasma torch, or even a second laser pulse. The additional ionization is often organized as a pulse (electrons, reagent gas, or laser) that follows very shortly after the... 

Engineering the required texture in a (RE)BCO tape is a much more complex matter than in the case of the Bi-2223 tape. One approach is to prepare a nickel tape with a carefully controlled crystalline surface texture. This forms the substrate for the development of a correspondingly textured thermally grown oxide layer which, in turn, forms the substrate for the epitaxial growth of MgO by electron beam evaporation. The textured MgO serves as the substrate for the epitaxial growth of the 1 /mi thick (RE)BCO via pulsed laser deposition. 

Shock initiation of lead azide by an electron beam has been compared with that of potassium dinitrobenzofuroxan (KDNBF), lead styphnate, and lead mononitroresorcinate (LMNR) [49], An aluminum slab was heated rapidly by electron deposition, generating a pressure pulse that propagated through the slab and was transmitted to a specimen bonded to its rear. The mean energy of the electrons was in the range of 900 keV and produced a stress pulse in the aluminum with a duration of approximately 0.2 psec. 

The effective P may be determined with the electron beam apparatus. When the sample (slab geometry) is thick enough to absorb all of the incident electrons, a compressive stress wave propagates from the irradiated region into the sample bulk. A transducer, located just beyond the deposition depth, may be used to record the stress pulse. Alternatively, the displacement or velocity of the rear surface of sample may be observed optically and used to infer the initial pressure distribution from the experimentally measured stress history. Knowledge of the energy-deposition profile then permits the determination of the Gruneisen coefficient. 

Fig. 3. Carbon K emission band for the carbon deposited by action of electron beam for a target potential of 4000 V, a beam current of 1.4 mA, and a deviation of 1% (n is the number of pulses per second).

Lasers and electron beams. These can be used to provide local heating or to heat small quantities. The temperature control is not great, but these techniques are very versatile. Electron beams are used to vaporize silicon for thin-film deposition using molecular-beam epitaxy. A focused laser beam is the basis of the pulsed-laser deposition (PLD) thin-film growth technique (Chapter 28). 

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