Energy spectra, backscattering

Fig. 3.18 Pulse-height analysis (PHA) spectrum (or energy spectrum) for Co/Rh Mossbauer source radiation backscattered nonresonantly and/or resonantly from aluminum and stainless steel plates. Data were obtained with Si-PIN diodes with sensitive area of 1 cm per diode and a thickness of 400 pm (from [36, 46])...

Figure 4.9. Sketch of CSTR representation of the SR model for 1 < Sc. Each wavenumber band is assumed to be well mixed in the sense that it can be represented by a single variable

In principle, the forward and backward transfer rates can be computed directly from DNS (see Appendix A). However, they are more easily computed by assuming idealized forms for the scalar energy spectrum (Fox 1995). In the general formulation (Fox 1999), they include both a forward cascade (a) and backscatter (/() ... 

Rutherford backscattering spectrometry spect A method of determining the concentrations of various elements as a function of depth beneath the surface of a sample, by measuring the energy spectrum of ions which are backscattered out of a beam directed at the surface. roth-or-ford bak,skad-3-rir spek tram-o-tre rutherfordium chem A chemical element, symbolized Rf, atomic number 104, a synthetic element the first element beyond the actinide series, and the twelfth transuranium element., r3lh 3t fdr-de-3m ... 

The energy spectrum of the backscattered He ions yields a peak for each atomic species. Its size is proportional to its concentration. As the He ions are submitted to further ineslastic energy losses during their way in and out, broad signals appear that depict the depth profile of the element. Usually the depth resolution is poor and corresponds to the energy resolution of the detector (ca. 5 nm). This method is therefore well suited for thick films. An example on the anodic oxidation of Cu/Al will be presented in a following chapter. 

LEIS measurements result in an energy spectrum of the backscattered ions from the sample surface. The energy of scattered ions provides information on the mass of the surface atoms, which is directly related to their chemical identity. The cross-section, solid angle and transmission factor (the analyser acts as an energy filter, with transmission characteristics that depend on the mode of operation) are used for these calculations. 

There is a sharp drop at the end of the continuous energy spectrum of the Compton electrons, the Compton edge, distinctly below the full energy of the original photon. The electron energy reaches its maximum when the photon is totally back scattered 9 - 180°). The energy of such backscattered photons - Ey — is therefore at minimum, but for... 

Figure 77. Schematic energy spectrum of emitted electrons with secondary (SE), backscattered (BSE), elastically reflected (ERE), low-loss (LEE), and Auger electrons (AE)...

Various methods of analyzing surfaces for chanical composition and physical texture. Electron spectroscopy for chemical analysis and Auger analysis [19] are techniqnes that have been used to identily chemical species in thin films. In Rutherford backscattering spectrometry incident He ions are scattered elastically by nuclei. The energy spectrum thus obtained can... 

Figure Bl.24.5. Backscattering spectrum of a thin Ni film (950 A) with near monolayers ( 30 x 10 at cm of An on the front and back surfaces of the Ni film. The signals from the front and back layers of An are shown and are separated in energy from each other by nearly the same energy width as the Ni signal.

Figure Bl.24.10. Random and aligned (chaimelled) backscattering spectrum from a single crystal sample of silicon. The aligned spectrum has a peak at the high energy end of the Si signal. This peak represents helium...

Figure 2 Micrographs of the same region of a specimen in various imaging modes on a high-resolution SEM (a) and (b) SE micrographs taken at 25 and 5 keV, respectively (c) backscattered image taken at 25 keV (d) EDS spectrum taken from the Pb-rich phase of the Pb-Sn solder (e) and (f) elemental maps of the two elements taken by accepting only signals from the appropriate spectral energy regions.

Figure 2 Molybdenum K-edge X-ray absorption spectrum, ln(i /i ) versus X-ray energy (eV), for molybdenum metal foil (25- jjn thick), obtained by transmission at 77 K with synchrotron radiation. The energy-dependent constructive and destructive interference of outgoing and backscattered photoelectrons at molybdenum produces the EXAFS peaks and valleys, respectively. The preedge and edge structures marked here are known together as X-ray absorption near edge structure, XANES and EXAFS are provided in a new compilation of literature entitled X-rsy Absorption Fine Structure (S.S. Hasain, ed.) Ellis Norwood, New York, 1991.

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