Contribution of Cerenkov radiation in high-energy x-ray and electron beam film dosimetry using water-substitute phantoms

2003 ◽  
Vol 48 (6) ◽  
pp. N105-N109 ◽  
Author(s):  
Tatsuya Fujisaki ◽  
Hidetoshi Saitoh ◽  
Takeshi Hiraoka ◽  
Akio Kuwabara ◽  
Shinji Abe ◽  
...  
Keyword(s):  
Electron Beam ◽  
High Energy ◽  
Cerenkov Radiation ◽  
Film Dosimetry ◽  
X Ray

Surface Structure of Sulfur Coated GaAs

1989 ◽  
Vol 163 ◽  
Author(s):  
Yoshihisa Fujisaki ◽  
Shigeo Goto
Keyword(s):  
Electron Beam ◽  
Surface Structure ◽  
Chemical Bond ◽  
Photoelectron Spectroscopy ◽  
Strong Dependence ◽  
High Energy ◽  
Chemical Bonds ◽  
High Energy Electron ◽  
X Ray ◽  
Beam Diffraction

AbstractSurface structure of (NH4)2S treated GaAs. is investigated using PL (PhotoLuminescence), XPS (X-ray Photoelectron Spectroscopy) and RHEED (Reflection of High Energy Electron beam Diffraction). The data taken with these techniques show the strong dependence upon the crystal orientations coming from the stabilities of chemical bonds of Ga-S and As-S on GaAs crystals. The greater enhancement of PL intensity, the clearer RHEED patterns and the smaller amount of oxides on (111)A than (111)B implies the realization of a more stable structure composed mainly of the Ga-S chemical bond.

X-ray spectroscopy and spectropolarimetry of high energy density plasma complemented by LLNL electron beam ion trap experiments

2003 ◽  
Vol 74 (3) ◽  
pp. 1947-1950 ◽  
Author(s):  
A. S. Shlyaptseva ◽  
D. A. Fedin ◽  
S. M. Hamasha ◽  
S. B. Hansen ◽  
C. Harris ◽  
...  
Keyword(s):  
Electron Beam ◽  
Energy Density ◽  
Ion Trap ◽  
High Energy ◽  
High Energy Density ◽  
X Ray ◽  
Electron Beam Ion Trap ◽  
Density Plasma

scholarly journals The importance of EBIT data for Z-pinch plasma diagnostics

2008 ◽  
Vol 86 (1) ◽  
pp. 267-276 ◽  
Author(s):  
A S Safronova ◽  
V L Kantsyrev ◽  
P Neill ◽  
U I Safronova ◽  
D A Fedin ◽  
...  
Keyword(s):  
Electron Beam ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Theoretical Models ◽  
High Energy ◽  
High Energy Density ◽  
Strong Electron ◽  
Model Calculations ◽  
X Ray ◽  
Z Pinch

The results from the last six years of X-ray spectroscopy and spectropolarimetry of high-energy density Z-pinch plasmas complemented by experiments with the electron beam ion trap (EBIT) at the Lawrence Livermore National Laboratory (LLNL) are presented. The two topics discussed are the development of M-shell X-ray W spectroscopic diagnostics and K-shell Ti spectropolarimetry of Z-pinch plasmas. The main focus is on radiation from a specific load configuration called an “X-pinch”. In this work the study of X-pinches with tungsten wires combined with wires from other, lower Z materials is reported. Utilizing data produced with the LLNL EBIT at different energies of the electron beam the theoretical prediction of line positions and intensity of M-shell W spectra were tested and calibrated. Polarization-sensitive X-pinch experiments at the University of Nevada, Reno (UNR) provide experimental evidence for the existence of strong electron beams in Ti and Mo X-pinch plasmas and motivate the development of X-ray spectropolarimetry of Z-pinch plasmas. This diagnostic is based on the measurement of spectra recorded simultaneously by two spectrometers with different sensitivity to the linear polarization of the observed lines and compared with theoretical models of polarization-dependent spectra. Polarization-dependent K-shell spectra from Ti X-pinches are presented and compared with model calculations and with spectra generated by a quasi-Maxwellian electron beam at the LLNL EBIT-II electron beam ion trap.PACS Nos.: 32.30.Rj, 52.58.Lq, 52.70.La

Energy-Dispersive Spectroscopy in A 400Kv Electron Microscope

1985 ◽  
Vol 43 ◽  
pp. 146-147
Author(s):  
S. Suzuki ◽  
Y. Bando ◽  
H. Kitajima ◽  
T. Honda ◽  
Y. Harada ◽  
...  
Keyword(s):  
Electron Beam ◽  
Energy Dispersive Spectroscopy ◽  
High Energy ◽  
Energy Dispersive ◽  
Resolving Power ◽  
Total Thickness ◽  
High Energy Electron ◽  
X Ray ◽  
Basic Performance ◽  
Electron Energy Loss

A Si(Li) detector for X-ray energy dispersive spectroscopy (EDS) has been installed on a 400 kV EM, the JEM-4000EX, which is also interfaced with a scanning device (ASID40) and electron energy loss spectrometer (ASEA40). The EM's basic performance, i.e., resolving power, is 0.23 nm at 400 kV. X-ray microanalysis in a high-voltage EM has many advantages, but few reports have been published because of some severe instrumental problems originating from it's high energy electron beam. To overcome these problems many modifications have been made on the EM column.The modifications are divided into two aspects. One is the reduction of bremsstrahlung and the other is the protection of the Si(Li) detector from hard X-ray radiation from the upper parts of the detector, especially condenser lens (CL) aperture. To reduce bremsstrahlung many parts of the wall which electron beam might hit are covered with graphite and the materials for CL fixed apertures are changed to light elements. To protect the detector X-ray shielding parts made of heavy metals (W, Ta, Pb) and with a total thickness of more than 30 mm are set between the CL aperture and the Si(Li) detector.

AEM: From microns to atoms

1992 ◽  
Vol 50 (2) ◽  
pp. 1464-1465
Author(s):  
Graham Cliff ◽  
Gordon W. Lorimer
Keyword(s):  
Electron Beam ◽  
Analytical Electron Microscopy ◽  
High Energy ◽  
Simple Relationship ◽  
X Ray ◽  
Physics Department ◽  
The University ◽  
University Of Manchester ◽  
A Current ◽  
Made In

The “Manchester Connection” with analytical electron microscopy (AEM) goes back to 1913 and the work of Moseley which was carried out in the Physics Department of the University of Manchester. It was Moseley who first pointed out that there is a simple relationship between Z, the atomic number of an element, and Ek,the energy of the characteristic K-shell X-ray. This relationship is enshrined in Moseley's Law, Ek = 10.3(Z-1).The origin of the modern bulk microprobe analyzer lies in the Ph.D. project of Castaing. Under the supervision of Guinier, Castaing combined an electron microscope and an X-ray spectrometer and obtained a current of a few nA in an electron beam under a micron in diameter. Although enormous advances were made in instrumentation and quantification in the 1950's and 1960's, the spatial resolution for microprobe analysis remained at about 1 μm3 or a mass of about 10-12g, no matter how small the diameter of the incident electron beam. This limitation arises from the physics of the interaction of a high energy electron beam with a solid sample.

scholarly journals Assesment Assessment of X-Ray converter for electron beam radiation processing facility

2020 ◽  
Vol 4 (4) ◽  
pp. First
Author(s):  
Nguyen Anh Tuan ◽  
Chau Van Tao
Keyword(s):  
Electron Beam ◽  
Cooling Water ◽  
High Energy ◽  
Radiation Processing ◽  
Beam Radiation ◽  
X Ray ◽  
High Area ◽  
Processing Facility ◽  
Circulating Cooling Water ◽  
Sludge Waste

Recently, a high energy electron beam from accelerators studied on the application for foods and medical devices irradiation, therapy, denature material, discolored semi-precious stones and degradation of environment pollution (Gas, Water, and Sludge Waste). The advantages of electron beam from accelerators are high power density and easy focusing on the target, but electron beam is only useful to irradiate on the surface of the irradiation product because their penetration is short. In order to irradiate high area density products, the X-ray converter is used to generate photon (bremsstrahlung effect). In this article, converting efficiency and direction of X-ray emission is measured by film dosimeter and simulated by MCNP-4c2 code. Measurement and simulation results show that converting efficiency depends on materials of the targets and electron energy, the converting efficiency of Ti – H2O – Pb converter at electron beam energy 5.0 MeV, 7.5 MeV, and 10.0 MeV are 5.57 %, 7.12 %, and 13.54 %. Ti – H2O – Pb converter is made up of 3 layers of Ti wrap material with the function of bearing, heat resistance, circulating cooling water between Ti and Pb layers to cooling, so it is applied for the accelerator.

Reflection Electron Diffraction of Catalase

1975 ◽  
Vol 33 ◽  
pp. 672-673
Author(s):  
T. K. Chatterjee ◽  
J. A. Spadaro ◽  
R. W. Vook
Keyword(s):  
Electron Beam ◽  
Electron Diffraction ◽  
Preliminary Report ◽  
Water Vapor Pressure ◽  
High Energy ◽  
High Energy Electron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Reflection Electron Diffraction

Matricardi et al. have shown that high energy electron diffraction patterns of unstained and unfixed catalase may be obtained with a high voltage TEM using a hydration stage and that without such a stage TED patterns could not be obtained. They showed that such patterns were observed only when the water vapor pressure in the vicinity of the catalase was greater than 90 percent of the equilibrium value. They attributed their results to the destruction of the crystallinity of catalase when it is vacuum dried. Similar results using X-ray diffraction techniques have been reported. Matricardi et al. also noted effects due to radiation damage, whereby the number of reflections observed using the hydration stage decreased substantially with electron beam exposure. In the present preliminary report, it is shown that electron diffraction patterns can be obtained from unstained and unfixed catalase even when the crystals are exposed directly to the vacuum of the TEM but under such conditions whereby the electron beam intensity is reduced by up to approximately two orders of magnitude from that usually obtained in normal TED work on a TEM.

scholarly journals Vertical intensity modulation for improved radiographic penetration and reduced exclusion zone

2016 ◽  
Vol 44 ◽  
pp. 1660213 ◽  
Author(s):  
J. Bendahan ◽  
W.G.J. Langeveld ◽  
V. Bharadwaj ◽  
J. Amann ◽  
C. Limborg ◽  
...  
Keyword(s):  
Electron Beam ◽  
High Energy ◽  
Dual Energy ◽  
X Rays ◽  
Exclusion Zone ◽  
Bremsstrahlung Radiation ◽  
Radiographic Images ◽  
Power Sources ◽  
X Ray ◽  
Energy Beam

In the present work, a method to direct the X-ray beam in real time to the desired locations in the cargo to increase penetration and reduce exclusion zone is presented. Cargo scanners employ high energy X-rays to produce radiographic images of the cargo. Most new scanners employ dual-energy to produce, in addition to attenuation maps, atomic number information in order to facilitate the detection of contraband. The electron beam producing the bremsstrahlung X-ray beam is usually directed approximately to the center of the container, concentrating the highest X-ray intensity to that area. Other parts of the container are exposed to lower radiation levels due to the large drop-off of the bremsstrahlung radiation intensity as a function of angle, especially for high energies (>6 MV). This results in lower penetration in these areas, requiring higher power sources that increase the dose and exclusion zone. The capability to modulate the X-ray source intensity on a pulse-by-pulse basis to deliver only as much radiation as required to the cargo has been reported previously. This method is, however, controlled by the most attenuating part of the inspected slice, resulting in excessive radiation to other areas of the cargo. A method to direct a dual-energy beam has been developed to provide a more precisely controlled level of required radiation to highly attenuating areas. The present method is based on steering the dual-energy electron beam using magnetic components on a pulse-to-pulse basis to a fixed location on the X-ray production target, but incident at different angles so as to direct the maximum intensity of the produced bremsstrahlung to the desired locations. The details of the technique and subsystem and simulation results are presented.

scholarly journals Residual Lattice Strain and Phase Distribution in Ti-6Al-4V Produced by Electron Beam Melting

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 667 ◽  
Author(s):  
Tuerdi Maimaitiyili ◽  
Robin Woracek ◽  
Magnus Neikter ◽  
Mirko Boin ◽  
Robert Wimpory ◽  
...  
Keyword(s):  
Residual Stress ◽  
Electron Beam ◽  
Electron Beam Melting ◽  
Phase Distribution ◽  
High Energy ◽  
Process Parameter ◽  
Electron Backscattered Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Residual Strains

Residual stress/strain and microstructure used in additively manufactured material are strongly dependent on process parameter combination. With the aim to better understand and correlate process parameters used in electron beam melting (EBM) of Ti-6Al-4V with resulting phase distributions and residual stress/strains, extensive experimental work has been performed. A large number of polycrystalline Ti-6Al-4V specimens were produced with different optimized EBM process parameter combinations. These specimens were post-sequentially studied by using high-energy X-ray and neutron diffraction. In addition, visible light microscopy, scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) studies were performed and linked to the other findings. Results show that the influence of scan speed and offset focus on resulting residual strain in a fully dense sample was not significant. In contrast to some previous literature, a uniform α- and β-Ti phase distribution was found in all investigated specimens. Furthermore, no strong strain variations along the build direction with respect to the deposition were found. The magnitude of strain in α and β phase show some variations both in the build plane and along the build direction, which seemed to correlate with the size of the primary β grains. However, no relation was found between measured residual strains in α and β phase. Large primary β grains and texture appear to have a strong effect on X-ray based stress results with relatively small beam size, therefore it is suggested to use a large beam for representative bulk measurements and also to consider the prior β grain size in experimental planning, as well as for mathematical modelling.

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