Angular Distribution of Electrons Elastically Scattered from Copper Surfaces, Polished and Textured by Argon Flux

1992 ◽  
Vol 279 ◽  
Author(s):  
Isay L. Krainsky
Keyword(s):  
Crystallization Process ◽  
Angular Distributions ◽  
Textured Surface ◽  
Ion Sputtering ◽  
Polycrystalline Structure ◽  
Secondary Electrons ◽  
Copper Surfaces ◽  
Atomic Scattering ◽  
Primary Electrons ◽  
Induced Crystallization

ABSTRACTAngular distributions of the elastically scattered secondary electrons from two kinds of Cu surfaces, polished and textured by 2 keV Ar+ have been studied in the energy range from 50 eV to 2 keV. The results show that for the polished Cu surface the elastic scattering process is dominated by atomic scattering from single atoms (although, contributions from othei processes are also important). However when the textured surface was studied, new multiple peaks appeared on the angular distributions. Positions of these peaks for the various angles of incidence and primary energies indicate that their origin lies in the diffraction of the primary electrons on some kind of a polycrystalline structure. This structure is probably created by the process of recrystallization induced by ion sputtering similar to the sputtering induced crystallization process already known for some oxides and nonmetallic compounds.

MAXIMUM SECONDARY ELECTRON YIELDS FROM SEMICONDUCTORS AND INSULATORS

2016 ◽  
Vol 24 (04) ◽  
pp. 1750045 ◽  
Author(s):  
A. G. XIE ◽  
Z. H. LIU ◽  
Y. Q. XIA ◽  
M. M. ZHU
Keyword(s):  
Electron Emission ◽  
Secondary Electron ◽  
Maximum Yield ◽  
Secondary Electron Emission ◽  
High Energy ◽  
Secondary Electrons ◽  
Backscattered Electrons ◽  
Universal Formula ◽  
Yield Formula ◽  
Primary Electrons

Based on the processes and characteristics of secondary electron emission and the formula for the yield due to primary electrons hitting on semiconductors and insulators, the universal formula for maximum yield [Formula: see text] due to primary electrons hitting on semiconductors and insulators was deduced, where [Formula: see text] is the maximum ratio of the number of secondary electrons produced by primary electrons to the number of primary electrons. On the basis of the formulae for primary range in different energy ranges of [Formula: see text], characteristics of secondary electron emission and the deduced universal formula for [Formula: see text], the formulae for [Formula: see text] in different energy ranges of [Formula: see text] were deduced, where [Formula: see text] is the primary incident energy at which secondary electron yields from semiconductors and insulators, [Formula: see text], are maximized to maximum secondary electron yields from semiconductors and insulators, [Formula: see text]; and [Formula: see text] is the maximum ratio of the number of total secondary electrons produced by primary electrons and backscattered electrons to the number of primary electrons. According to the deduced formulae for [Formula: see text], the relationship among [Formula: see text], [Formula: see text] and high-energy back-scattering coefficient [Formula: see text], the formulae for parameters of [Formula: see text] and the experimental data as well as the formulae for [Formula: see text] in different energy ranges of [Formula: see text] as a function of [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] were deduced, where [Formula: see text] and [Formula: see text] are the original electron affinity and the width of forbidden band, respectively. The scattering of [Formula: see text] was analyzed, and calculated [Formula: see text] values were compared with the values measured experimentally. It was concluded that the deduced formulae for [Formula: see text] were found to be universal for [Formula: see text].

scholarly journals Application of Polymers as a Tool in Crystallization—A Review

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2695
Author(s):  
Marcin Lemanowicz ◽  
Anna Mielańczyk ◽  
Tomasz Walica ◽  
Milena Kotek ◽  
Andrzej Gierczycki
Keyword(s):  
Crystallization Process ◽  
Rapid Development ◽  
Theoretical Models ◽  
Crystalline Materials ◽  
Crystal Properties ◽  
Efficient Control ◽  
Water And Wastewater ◽  
Controlled Crystallization ◽  
Scientific Periodicals ◽  
Induced Crystallization

The application of polymers as a tool in the crystallization process is gaining more and more interest among the scientific community. According to Web of Science statistics the number of papers dealing with “Polymer induced crystallization” increased from 2 in 1990 to 436 in 2020, and for “Polymer controlled crystallization”—from 4 in 1990 to 344 in 2020. This is clear evidence that both topics are vivid, attractive and intensively investigated nowadays. Efficient control of crystallization and crystal properties still represents a bottleneck in the manufacturing of crystalline materials ranging from pigments, antiscalants, nanoporous materials and pharmaceuticals to semiconductor particles. However, a rapid development in precise and reliable measuring methods and techniques would enable one to better describe phenomena involved, to formulate theoretical models, and probably most importantly, to develop practical indications for how to appropriately lead many important processes in the industry. It is clearly visible at the first glance through a number of representative papers in the area, that many of them are preoccupied with the testing and production of pharmaceuticals, while the rest are addressed to new crystalline materials, renewable energy, water and wastewater technology and other branches of industry where the crystallization process takes place. In this work, authors gathered and briefly discuss over 100 papers, published in leading scientific periodicals, devoted to the influence of polymers on crystallizing solutions.

Two contributions to the ratio of the mean secondary electron generation of backscattered electrons to primary electrons at high electron energy

2014 ◽  
Vol 28 (06) ◽  
pp. 1450046 ◽  
Author(s):  
Ai-Gen Xie ◽  
Chen-Yi Zhang ◽  
Kun Zhong
Keyword(s):  
Atomic Number ◽  
Secondary Electron ◽  
High Energy ◽  
Primary Electron ◽  
Experimental Results ◽  
High Electron ◽  
Secondary Electrons ◽  
Backscattered Electrons ◽  
The Mean ◽  
Primary Electrons

Based on the main physical processes of secondary electron emission, experimental results and the characteristics of backscattered electrons (BE), the formula was derived for describing the ratio (β angle ) of the number of secondary electrons excited by the larger average angle of emission BE to the number of secondary electrons excited by the primary electrons of normal incidence. This ratio was compared to the similar ratio β obtained in the case of high energy primary electrons. According to the derived formula for β angle and the two reasons why β > 1, the formula describing the ratio β energy of β to β angle , reflecting the effect that the mean energy of the BE W AV p0 is smaller than the energy of the primary electrons at the surface, was derived. β angle and β energy computed using the experimental results and the deduced formulae for β angle and β energy were analyzed. It is concluded that β angle is not dependent on atomic number z, and that β energy decreases slowly with z. On the basis of the two reasons why β > 1, the definitions of β and β energy and the number of secondary electrons released per primary electron, the formula for β E-energy (the estimated β energy ) was deduced. The β E-energy computed using W AV p0, energy exponent and the formula for β E-energy is in a good agreement with β energy computed using the experimental results and the deduced formula for β energy . Finally, it is concluded that the deduced formulae for β angle and β energy can be used to estimate β angle and β energy , and that the factor that W AV p0 increases slowly with atomic number z leads to the results that β energy decreases slowly with z and β decreases slowly with z.

scholarly journals The shape of the continuous β -spectrum of thorium C. C'

1937 ◽  
Vol 162 (910) ◽  
pp. 391-403 ◽  
Author(s):  
H. O. W. Richardson ◽  
Alice Leigh-Smith ◽  
James Chadwick
Keyword(s):  
Low Energy ◽  
Considerable Proportion ◽  
Secondary Electrons ◽  
Fast Electrons ◽  
Low Energies ◽  
Ionisation Chamber ◽  
Pass Through ◽  
Slow Electrons ◽  
Primary Electrons ◽  
Apparent Conflict

The theories of β -decay based on the neutrino hypothesis predict that a considerable proportion of the electrons emitted from a heavy nucleus will have low energies, owing to the Coulomb attraction between the electron and the nucleus. This prediction has been in apparent conflict with most experimental curves (Madgwick 1927; Scott 1935 ), which show the ordinate of the energy distribution falling to zero at the origin or even before it, thus even indicating a low energy end-point below which no β -rays are emitted. It is, however, probable that the experimental uncertainties in the methods which have been used are such that no definite conclusion can be drawn from them about the shape of the low energy end of the spectrum. In these methods the source is deposited on a solid mounting and the emitted β -particles pass through a window in entering the detecting apparatus, which may be a counter, a cloud chamber or an ionisation chamber. The window stops all β -particles below a certain energy, while those which pass through are reduced in energy and considerably scattered. These effects, which are well shown in curves given by Eddy (1928), produce a marked falling off in the observed number of β -particles of low energy. The use of a solid mounting for the source introduced opposite effects giving an increased number of slow electrons; for firstly, the fast electrons will eject slow secondary electrons from the solid mounting and, secondly, if the mounting is thick, a considerable reflexion of the primary electrons will occur with varying losses of energy inside the solid, so that the reflected spectrum will contain relatively more low energy rays.

In-situ observation of phase transformation in amorphous silicon during Joule-heating induced crystallization process

2011 ◽  
Vol 519 (16) ◽  
pp. 5516-5522 ◽  
Author(s):  
Dong-Hyun Kim ◽  
Won-Eui Hong ◽  
Jae-Sang Ro ◽  
Seong Hyuk Lee ◽  
Chang-Hoon Lee ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Amorphous Silicon ◽  
Joule Heating ◽  
Crystallization Process ◽  
In Situ Observation ◽  
Induced Crystallization

Angular distributions of secondary electrons emitted in Ar+-polycrystalline Al collisions

1984 ◽  
Vol 136 (2-3) ◽  
pp. A17
Author(s):  
Josette Mischler ◽  
Nicole Benazeth ◽  
Michel Nègre ◽  
Claude Benazeth
Keyword(s):  
Angular Distributions ◽  
Secondary Electrons
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