CHANNELING EXPERIMENTS WITH ELECTRONS AT THE MAINZ MICROTRON MAMI

2010 ◽  
Vol 25 (supp01) ◽  
pp. 136-143 ◽  
Author(s):  
W. LAUTH ◽  
H. BACKE ◽  
P. KUNZ ◽  
A. RUEDA
Keyword(s):  
Energy Loss ◽  
Crystal Orientation ◽  
High Energy ◽  
Low Energy ◽  
Crystal Thickness ◽  
Beam Direction ◽  
Bremsstrahlung Photon ◽  
Total Electron ◽  
Total Electron Energy ◽  
Energy Signal

The dechanneling process of electrons in silicon single crystals has been studied at the Mainz Microtron MAMI for (110)-planar channeling of electrons at beam energies between 195 and 855 MeV. Dechanneling lengths were derived from a high and a low energy loss signal of the electrons which were recorded as function of the crystal orientation with respect to the beam direction for various crystal thicknesses in the range between 14.7 µm and 467 µm. The high energy loss signal corresponds to an energy loss of about 75 % of the total electron energy by emission of a bremsstrahlung photon, while the low energy signal to an energy loss of 0.7-1.7 % by emission of channelling radiation. While the high energy signal saturates as function of the crystal thickness, the low energy signal does not. The nearly constant dechanneling length of about 35 µm, as extracted from the high energy signal, is interpreted to originate from a small fraction of electron which initially occupy deeply bound quantum states.

Thickness Measurement of Focused Ion Beam Thinned Silicon Crystals Using Convergent Beam.Electron Diffraction and Electron Energy Loss Spectroscopy.

1999 ◽  
Vol 5 (S2) ◽  
pp. 898-899
Author(s):  
D. Delille ◽  
R. Pantel ◽  
G. Auvert ◽  
E. Van Cappellen
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
High Energy ◽  
Thickness Measurement ◽  
Crystal Thickness ◽  
Ion Milling ◽  
Electron Energy Loss

1. IntroductionThe FIB (focused ion beam) is now widely accepted as the most site-specific TEM preparation tool and as such proves to be highly valuable when analysing ULSI devices. However, using high-energy Gallium ions for milling induces amorphization of the crystal surfaces. A method able to quantify this surface alteration on silicon using a combination of CBED (convergent beam electron diffraction) and EELS (electron energy loss spectroscopy) is presented. CBED is a powerful tool that also can generate an accurate measure of crystal thickness. EELS can yield the total sample thickness, so from the difference the combined amorphous layers can be assessed. Two sets of application results are presented: the first one is obtained on a FIB thinned sample using an ion energy of 50 keV and the second set of results confirms the validity of the proposed method on a mechanically polished specimen with no subsequent ion milling.

scholarly journals Identification of 90Sr and 204Tl beta radiation sources by energy distribution with a 3GEM detector

DYNA ◽  
2020 ◽  
Vol 87 (215) ◽  
pp. 174-179
Author(s):  
Freddy Fuentes Robayo ◽  
Rafael Maria Gutierrez Salamanca
Keyword(s):  
Energy Loss ◽  
Energy Distribution ◽  
Industrial Application ◽  
Radiation Source ◽  
Radiation Detection ◽  
High Energy ◽  
Low Energy ◽  
Beta Radiation ◽  
Detection And Identification ◽  
Radiation Sources

This paper presents the performance of a 3GEM in terms of identification of high and low beta energy radiation sources through the energy distribution of the main beta radiation sources used for industrial application 90Sr and 204Tl. We compare the beta radiation theoretical energy loss into the drift zone with experimental energy distribution at different 3GEM voltages. The experimental results show that the Most Probable Value (MPV) of the fitted Landau distribution obtained from 90Sr and 204Tl obtained a degree of error lower than 14% in comparison to the theoretical calculation. Additionally, high energy beta radiation source (90Sr) is identified in comparison to low energy (204Tl) - taking into account the MPV and sigma values from the fitted Landau distribution. These results are essential to design and implement a new application that utilizes the performance and special characteristics of the 3GEM for beta radiation detection and identification.

Angle-Resolved Energy-Loss Spectra of Gd2O3

1990 ◽  
Vol 48 (2) ◽  
pp. 20-21
Author(s):  
P. Schattschneider ◽  
F. Hofer
Keyword(s):  
Energy Loss ◽  
Loss Function ◽  
Energy Resolution ◽  
Intensity Variation ◽  
High Energy ◽  
Low Energy ◽  
Double Scattering ◽  
Interband Transitions ◽  
Diffraction Mode ◽  
Energy Maximum

Energy loss spectra of heavy rare earths oxides show two well defined plasmon-like peaks below 40 eV and some intensity variation beyond. Since the high-energy maximum is at about twice the energy as the low-energy maximum, double scattering contributions may mask the former. This effect induces artifacts when one attempts to determine the dielectric function ε(ω) from Kramers-Kronig-analysis (KKA) of the loss spectrum. Knowledge of ε(ω) allows to heuristically assign interband transitions or plasma excitations to particular maxima. Measurements in diffraction mode allow detection of dispersive features in ε(ω,q).Polycrystalline Gd2O3-films of of 40 nm thickness were investigated at 120 kV in a Philips EM420, attached to which is a Gatan 607 Spectrometer. Spectra were taken in diffraction mode (image coupling) at 8 scattering angles with a q-resolution of ≈ 0.03 Å-1. Energy resolution was ≈ 2 eV. The spectra were combined to a q-dependent loss function, using aperture correction.

scholarly journals Mg-Based Hydrogen Absorbing Materials for Thermal Energy Storage—A Review

2018 ◽  
Vol 8 (8) ◽  
pp. 1375 ◽  
Author(s):  
Bo Li ◽  
Jianding Li ◽  
Huaiyu Shao ◽  
Liqing He
Keyword(s):  
Energy Storage ◽  
Energy Density ◽  
Energy Loss ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Storage ◽  
High Energy ◽  
Low Energy ◽  
Potential Candidate ◽  
Chemical Heat

Utilization of renewable energy such as solar, wind, and geothermal power, appears to be the most promising solution for the development of sustainable energy systems without using fossil fuels. Energy storage, especially to store the energy from fluctuating power is quite vital for smoothing out energy demands with peak/off-peak hour fluctuations. Thermal energy is a potential candidate to serve as an energy reserve. However, currently the development of thermal energy storage (TES) by traditional physical means is restricted by the relatively low energy density, high temperature demand, and the great thermal energy loss during long-period storage. Chemical heat storage is one of the most promising alternatives for TES due to its high energy density, low energy loss, flexible temperature range, and excellent storage duration. A comprehensive review on the development of different types of Mg-based materials for chemical heat storage is presented here and the classic and state-of-the-art technologies are summarized. Some related chemical principles, as well as heat storage properties, are discussed in the context. Finally, some dominant factors of chemical heat storage materials are concluded and the perspective is proposed for the development of next-generation chemical heat storage technologies.

RESONANT INELASTIC SOFT X-RAY SCATTERING OF INSULATING CUPRATES

2002 ◽  
Vol 09 (02) ◽  
pp. 1103-1108 ◽  
Author(s):  
L.-C. DUDA ◽  
T. SCHMITT ◽  
J. NORDGREN ◽  
G. DHALENNE ◽  
A. REVCOLEVSCHI
Keyword(s):  
High Resolution ◽  
Energy Loss ◽  
Lower Energy ◽  
High Energy ◽  
Low Energy ◽  
The Novel ◽  
Excitation Peak ◽  
X Ray ◽  
X Ray Scattering ◽  
Large Spread

We have performed high-resolution inelastic X-ray emission scattering experiments at the Cu 3p-, Cu 3s-, and O 1s-resonances of the insulating cuprates CuGeO 3, CuO, La 2 CuO 4, and SrCuO 2. We introduce the novel low-energy s-edge Cu-RIXS which reveals a dd-excitation peak, which was previously unobserved due to insufficient resolution and intensity in high-energy (Cu 1s RIXS). Also, O 1s-RIXS of all cuprate sample is investigated. Surprisingly, there is a large spread in the energy loss values of the RIXS features for different compounds and we explain this by assigning the larger energy features to the occurrence of a Zhang–Rice singlet while the lower energy feature (only observed for CuGeO 3) is assigned to a dd-excitation.

scholarly journals The low energy β-rays of radium E

1934 ◽  
Vol 147 (862) ◽  
pp. 442-454 ◽  
Keyword(s):  
Energy Loss ◽  
Continuous Spectrum ◽  
Energy Region ◽  
High Energy ◽  
Experimental Information ◽  
Low Energy ◽  
Expansion Chamber ◽  
High Energy Part ◽  
Energy Part ◽  
Γ Ray

The object of this work was to obtain information about the shape of the low energy end of the continuous β-ray spectrum of radium E, an element convenient because of its negligible γ-ray emission. The failure of theory to explain the continuous spectrum makes it of interest to obtain all possible experimental information, and although much is now known about the high energy part of the curve, the low energy region has remained obscure owing to certain experimental difficulties. The chief of these has been the contamination of the low energy end of the curve by rays reflected with unknown energy loss from the material on which the radioactive body was deposited. This effect can be eliminated by mounting it on sufficiently thin metal leaf so that no particles can be reflected with appreciable loss of energy. Such a source would be too weak to use in a magnetic spectrograph, and the method therefore adopted in this work was out to mount it in a Wilson expansion chamber and take stereoscopic photographs from which the ranges of any slow tracks formed could be measured, a method already used by the writer for radium D.

scholarly journals Grain size effect on the radiation damage tolerance of cubic zirconia against simultaneous low and high energy heavy ions: Nano triumphs bulk

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Parswajit Kalita ◽  
Santanu Ghosh ◽  
Gaëlle Gutierrez ◽  
Parasmani Rajput ◽  
Vinita Grover ◽  
...  
Keyword(s):  
Grain Size ◽  
Energy Loss ◽  
Radiation Damage ◽  
Damage Tolerance ◽  
High Energy ◽  
Electronic Energy ◽  
Nuclear Industry ◽  
Low Energy ◽  
Cubic Zirconia ◽  
High Energy Particles

AbstractIrradiation induced damage in materials is highly detrimental and is a critical issue in several vital science and technology fields, e.g., the nuclear and space industries. While the effect of dimensionality (nano/bulk) of materials on its radiation damage tolerance has been receiving tremendous interest, studies have only concentrated on low energy (nuclear energy loss (Sn) dominant) and high energy (electronic energy loss (Se) dominant) irradiations independently (wherein, interestingly, the effect is opposite). In-fact, research on radiation damage in general has almost entirely focused only on independent irradiations with low and/or high energy particles till date, and investigations under simultaneous impingement of energetic particles (which also correspond to the actual irradiation conditions during real-world applications) are very scarce. The present work elucidates, taking cubic zirconia as a model system, the effect of grain size (26 nm vs 80 nm) on the radiation tolerance against simultaneous irradiation with low energy (900 keV I) and high energy (27 meV Fe) particles/ions; and, in particular, introduces the enhancement in the radiation damage tolerance upon downsizing from bulk to nano dimension. This result is interpreted within the framework of the thermal-spike model after considering (1) the fact that there is essentially no spatial and time overlap between the damage events of the two ‘simultaneous’ irradiations, and (2) the influence of grain size on radiation damage against individual Sn and Se. The present work besides providing the first fundamental insights into how the grain size/grain boundary density inherently mediates the radiation response of a material to simultaneous Sn and Se deposition, also (1) paves the way for potential application of nano-crystalline materials in the nuclear industry (where simultaneous irradiations with low and high energy particles correspond to the actual irradiation conditions), and (2) lays the groundwork for understanding the material behaviour under other simultaneous (viz. Sn and Sn, Se and Se) irradiations.

Fast calibration of CBED patterns for quantitative analysis

1993 ◽  
Vol 51 ◽  
pp. 674-675
Author(s):  
M.A. Gribelyuk ◽  
M. Rühle
Keyword(s):  
Reciprocal Lattice ◽  
Accurate Determination ◽  
Incident Beam ◽  
Crystal Thickness ◽  
Structure Model ◽  
Beam Direction ◽  
Transmitted Beam ◽  
Reciprocal Vector ◽  
On Line

A new method is suggested for the accurate determination of the incident beam direction K, crystal thickness t and the coordinates of the basic reciprocal lattice vectors V1 and V2 (Fig. 1) of the ZOLZ plans in pixels of the digitized 2-D CBED pattern. For a given structure model and some estimated values Vest and Kest of some point O in the CBED pattern a set of line scans AkBk is chosen so that all the scans are located within CBED disks.The points on line scans AkBk are conjugate to those on A0B0 since they are shifted by the reciprocal vector gk with respect to each other. As many conjugate scans are considered as CBED disks fall into the energy filtered region of the experimental pattern. Electron intensities of the transmitted beam I0 and diffracted beams Igk for all points on conjugate scans are found as a function of crystal thickness t on the basis of the full dynamical calculation.

Monte Carlo Modelling of Secondary Electron Yield from Rough Surfaces

1990 ◽  
Vol 48 (1) ◽  
pp. 422-423
Author(s):  
John C. Russ
Keyword(s):  
Monte Carlo ◽  
Energy Loss ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Analytical Calculation ◽  
Mean Free Path ◽  
Single Scattering ◽  
High Energy ◽  
Secondary Electron Yield ◽  
Electron Yield

Monte-Carlo programs are well recognized for their ability to model electron beam interactions with samples, and to incorporate boundary conditions such as compositional or surface variations which are difficult to handle analytically. This success has been especially powerful for modelling X-ray emission and the backscattering of high energy electrons. Secondary electron emission has proven to be somewhat more difficult, since the diffusion of the generated secondaries to the surface is strongly geometry dependent, and requires analytical calculations as well as material parameters. Modelling of secondary electron yield within a Monte-Carlo framework has been done using multiple scattering programs, but is not readily adapted to the moderately complex geometries associated with samples such as microelectronic devices, etc.This paper reports results using a different approach in which simplifying assumptions are made to permit direct and easy estimation of the secondary electron signal from samples of arbitrary complexity. The single-scattering program which performs the basic Monte-Carlo simulation (and is also used for backscattered electron and EBIC simulation) allows multiple regions to be defined within the sample, each with boundaries formed by a polygon of any number of sides. Each region may be given any elemental composition in atomic percent. In addition to the regions comprising the primary structure of the sample, a series of thin regions are defined along the surface(s) in which the total energy loss of the primary electrons is summed. This energy loss is assumed to be proportional to the generated secondary electron signal which would be emitted from the sample. The only adjustable variable is the thickness of the region, which plays the same role as the mean free path of the secondary electrons in an analytical calculation. This is treated as an empirical factor, similar in many respects to the λ and ε parameters in the Joy model.

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