WorldWideScience

Sample records for electron irradiation damage

  1. Irradiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Howe, L.M

    2000-07-01

    There is considerable interest in irradiation effects in intermetallic compounds from both the applied and fundamental aspects. Initially, this interest was associated mainly with nuclear reactor programs but it now extends to the fields of ion-beam modification of metals, behaviour of amorphous materials, ion-beam processing of electronic materials, and ion-beam simulations of various kinds. The field of irradiation damage in intermetallic compounds is rapidly expanding, and no attempt will be made in this chapter to cover all of the various aspects. Instead, attention will be focused on some specific areas and, hopefully, through these, some insight will be given into the physical processes involved, the present state of our knowledge, and the challenge of obtaining more comprehensive understanding in the future. The specific areas that will be covered are: point defects in intermetallic compounds; irradiation-enhanced ordering and irradiation-induced disordering of ordered alloys; irradiation-induced amorphization.

  2. Irradiation damage

    International Nuclear Information System (INIS)

    Howe, L.M.

    2000-01-01

    There is considerable interest in irradiation effects in intermetallic compounds from both the applied and fundamental aspects. Initially, this interest was associated mainly with nuclear reactor programs but it now extends to the fields of ion-beam modification of metals, behaviour of amorphous materials, ion-beam processing of electronic materials, and ion-beam simulations of various kinds. The field of irradiation damage in intermetallic compounds is rapidly expanding, and no attempt will be made in this chapter to cover all of the various aspects. Instead, attention will be focused on some specific areas and, hopefully, through these, some insight will be given into the physical processes involved, the present state of our knowledge, and the challenge of obtaining more comprehensive understanding in the future. The specific areas that will be covered are: point defects in intermetallic compounds; irradiation-enhanced ordering and irradiation-induced disordering of ordered alloys; irradiation-induced amorphization

  3. Comparison of initial damage rates using neutron and electron irradiations

    International Nuclear Information System (INIS)

    Goldstone, J.A.R.

    1978-08-01

    The purpose of this experiment was twofold: (1) The number of interstitials that pin dislocations was studied as a function of neutron energy. (2) By comparison with electron irradiations on the sample, a correlation between the predicted and measured numbers of defects was found. All irradiations were performed on the same high purity copper sample. The sample was machined in the form of a cantilever beam with a flexural resonant frequency of 770 Hz. Changes in Young's modulus at constant strain amplitude were monitored continuously through changes in the resonant frequency of the sample. These changes in the modulus can be related to the number of pinning points added to dislocation lines, which are in turn related to the number of free interstitials produced. Neutron energy dependence experiments were done from 2 to 24 MeV on the copper sample and at 14 MeV on a gold sample. By equating pinning rates from electron and neutron irradiations and using the free interstitial production rate obtained from electron irradiations, an estimate of the free interstitial production cross section for neutrons of 2 to 24 MeV was made

  4. Effect of low energy electron irradiation on DNA damage by Cu{sup 2+} ion

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Hyung Ah; Cho, Hyuck [Dept. of Physics, Chungnam National University, Daejeon (Korea, Republic of); Park, Yeun Soo [Plasma Technology Research Center, National Fusion Research Institute, Gunsan (Korea, Republic of)

    2017-03-15

    The combined effect of the low energy electron (LEE) irradiation and Cu{sup 2+} ion on DNA damage was investigated. Lyophilized pBR322 plasmid DNA films with various concentrations (1–15 mM) of Cu{sup 2+} ion were independently irradiated by monochromatic LEEs with 5 eV. The types of DNA damage, single strand break (SSB) and double strand break (DSB), were separated and quantified by gel electrophoresis. Without electron irradiation, DNA damage was slightly increased with increasing Cu ion concentration via Fenton reaction. LEE-induced DNA damage, with no Cu ion, was only 6.6% via dissociative electron attachment (DEA) process. However, DNA damage was significantly increased through the combined effect of LEE-irradiation and Cu ion, except around 9 mM Cu ion. The possible pathways of DNA damage for each of these different cases were suggested. The combined effect of LEE-irradiation and Cu ion is likely to cause increasing dissociation after elevated transient negative ion state, resulting in the enhanced DNA damage. For the decrease of DNA damage at around 9-mM Cu ion, it is assumed to be related to the structural stabilization due to DNA inter- and intra-crosslinks via Cu ion.

  5. Subthreshold displacement damage in copper--aluminum alloys during electron irradiation

    International Nuclear Information System (INIS)

    Drosd, R.; Kosel, T.; Washburn, J.

    1976-12-01

    During electron irradiation at low energies which results in a negligible damage rate in a pure material, lighter solute atoms are displaced, which may in turn indirectly displace solvent atoms by a focussed replacement collision or an interstitial diffusion jump. The extent to which lighter solute atoms contribute to the subthreshold damage rate has been examined by irradiating copper--aluminum alloys at high temperatures in a high voltage electron microscope. The damage rate, as measured by monitoring the growth rate of dislocation loops, at 300 kV was found to increase linearly with the aluminum concentration

  6. Simulating Neutron Radiation Damage of Graphite by In-situ Electron Irradiation

    International Nuclear Information System (INIS)

    Mironov, Brindusa E; Freeman, H M; Brydson, R M D; Westwood, A V K; Scott, A J

    2014-01-01

    Radiation damage in nuclear grade graphite has been investigated using transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). Changes in the structure on the atomic scale and chemical bonding, and the relationship between each were of particular interest. TEM was used to study damage in nuclear grade graphite on the atomic scale following 1.92×10 8 electrons nm −2 of electron beam exposure. During these experiments EELS spectra were also collected periodically to record changes in chemical bonding and structural disorder, by analysing the changes of the carbon K-edge. Image analysis software from the 'PyroMaN' research group provides further information, based on (002) fringe analysis. The software was applied to the micrographs of electron irradiated virgin 'Pile Grade A' (PGA) graphite to quantify the extent of damage from electron beam exposure

  7. Electron Beam Irradiation Dose Dependently Damages the Bacillus Spore Coat and Spore Membrane

    Directory of Open Access Journals (Sweden)

    S. E. Fiester

    2012-01-01

    Full Text Available Effective control of spore-forming bacilli begs suitable physical or chemical methods. While many spore inactivation techniques have been proven effective, electron beam (EB irradiation has been frequently chosen to eradicate Bacillus spores. Despite its widespread use, there are limited data evaluating the effects of EB irradiation on Bacillus spores. To study this, B. atrophaeus spores were purified, suspended in sterile, distilled water, and irradiated with EB (up to 20 kGy. Irradiated spores were found (1 to contain structural damage as observed by electron microscopy, (2 to have spilled cytoplasmic contents as measured by spectroscopy, (3 to have reduced membrane integrity as determined by fluorescence cytometry, and (4 to have fragmented genomic DNA as measured by gel electrophoresis, all in a dose-dependent manner. Additionally, cytometry data reveal decreased spore size, increased surface alterations, and increased uptake of propidium iodide, with increasing EB dose, suggesting spore coat alterations with membrane damage, prior to loss of spore viability. The present study suggests that EB irradiation of spores in water results in substantial structural damage of the spore coat and inner membrane, and that, along with DNA fragmentation, results in dose-dependent spore inactivation.

  8. Damage structure of gallium arsenide irradiated in a high-voltage electron microscope

    International Nuclear Information System (INIS)

    Loretto, D.; Loretto, M.H.

    1989-01-01

    Semi-insulating undoped gallium arsenide has been irradiated in a high-voltage electron microscope between room temperature and about 500 0 C for doses of up to 5 x 10 22 electrons cm -2 at 1 MeV. Room-temperature irradiation produces small (less than 5 nm) damage clusters. As the temperature of the irradiation is increased, the size of these clusters increases, until at about 300 0 C a high density of dislocation loops can be resolved. The dislocation loops, 20 nm or less in diameter, which are produced at about 500 0 C have been analysed in a bright field using a two-beam inside-outside method which minimises the tilt necessary between micrographs. It is concluded that the loops are an interstitial perfect-edge type with a Burgers vector of (a/2) . (author)

  9. Multiwalled carbon nanotube destruction in the radiation damages to electron irradiation

    Directory of Open Access Journals (Sweden)

    T. M. Pinchuk-Rugal’

    2015-10-01

    Full Text Available Behavior of the X-ray diffraction and vibrational Raman spectra of multiwalled carbon nanotubes (MWCNT under high-energy electron irradiation (Ee = 1.8 MeV with large doses of absorption to 10 MGy were studied. With increasing dose uptake to 10.0 MGy, the interlayer correlation in the distribution of the individual graphene nanotubes nets not only is maintained, but is even improved. Defective bands D, D' and G band with increasing dose absorption have significant transformation, which show radiation damages of MWCNT. The destruction of nanotubes under electron irradiation is accompanied by increased regulation in the arrangement of individual nanotubes by interlayer cross-links involving interstitial atoms. The severity of degradation and cross-linking of MWCNT depends on the electron absorption dose.

  10. High-energy electron irradiation of NdFeB permanent magnets: Dependence of radiation damage on the electron energy

    International Nuclear Information System (INIS)

    Bizen, Teruhiko; Asano, Yoshihiro; Marechal, Xavier-Marie; Seike, Takamitsu; Aoki, Tsuyoshi; Fukami, Kenji; Hosoda, Naoyasu; Yonehara, Hiroto; Takagi, Tetsuya; Hara, Toru; Tanaka, Takashi; Kitamura, Hideo

    2007-01-01

    High-energy electron-beam bombardment of Nd 2 Fe 14 B-type permanent magnets induces radiation damage characterized by a drop in the magnetic field. Experiments carried out at the SPring-8 booster synchrotron, with 4, 6, and 8 GeV electrons, show that the drop in magnetic field is energy dependent. Electromagnetic shower simulations suggest that most of the radiation damage happens in a small region around the irradiation axis, and that the contribution of neutrons with large scattering angles or with low energies to the magnetic field change is small

  11. High-energy electron irradiation of NdFeB permanent magnets: Dependence of radiation damage on the electron energy

    Energy Technology Data Exchange (ETDEWEB)

    Bizen, Teruhiko [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan)]. E-mail: bizen@spring8.or.jp; Asano, Yoshihiro [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); RIKEN SPring-8 Center, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Marechal, Xavier-Marie [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Seike, Takamitsu [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Aoki, Tsuyoshi [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Fukami, Kenji [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Hosoda, Naoyasu [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Yonehara, Hiroto [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Takagi, Tetsuya [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Hara, Toru [RIKEN SPring-8 Center, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Tanaka, Takashi [RIKEN SPring-8 Center, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Kitamura, Hideo [RIKEN SPring-8 Center, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

    2007-05-11

    High-energy electron-beam bombardment of Nd{sub 2}Fe{sub 14}B-type permanent magnets induces radiation damage characterized by a drop in the magnetic field. Experiments carried out at the SPring-8 booster synchrotron, with 4, 6, and 8 GeV electrons, show that the drop in magnetic field is energy dependent. Electromagnetic shower simulations suggest that most of the radiation damage happens in a small region around the irradiation axis, and that the contribution of neutrons with large scattering angles or with low energies to the magnetic field change is small.

  12. Radiation damage studies on natural and synthetic rock salt utilizing measurements made during electron irradiation

    International Nuclear Information System (INIS)

    Swyler, K.J.; Levy, P.W.

    1977-01-01

    The numerous radiation damage effects which will occur in the rock salt surrounding radioactive waste disposal canisters are being investigated with unique apparatus for making optical and other measurements during 1 to 3 MeV electron irradiation. This equipment, consists of a computer controlled double beam spectrophotometer which simultaneously records 256 point absorption and radioluminescence spectra, in either the 200 to 400 or 400 to 800 nm region, every 40 seconds. Most often the measurements commence as the irradiation is started and continue after it is terminated. This procedure provides information on the kinetics and other details of the damage formation process and, when the irradiation is terminated, on both the transient and stable damage components. The exposure rates may be varied between 10 2 or 10 3 to more than 10 8 rad per hour and the sample temperature maintained between 25 and 800 or 900 0 C. Although this project was started recently, measurements have been made on synthetic NaCl and on natural rock salt from two disposal sites and two mines. Both unstrained and purposely strained samples have been used. Most recently, measurements at temperatures between 25 and 200 0 C have been started. The few measurements completed to date indicate that the damage formation kinetics in natural rock salt are quite different from those observed in synthetic NaCl

  13. Molecular dynamics simulations of the role of electronic losses in damage creation of ion irradiated Tungsten

    International Nuclear Information System (INIS)

    Maya, P.N.; Deshpande, S.P

    2014-01-01

    Damage creation due to the irradiation of 14 MeV fusion neutrons and the subsequent mechanical failure and alteration of the fuel retention properties of tungsten plasma-facing materials is one of the major concerns of the fusion reactors. In addition to nuclear reactions and the subsequent transmutations, the energetic neutron impars its kinetic energy either partly or completely to a lattice tungsten atom thereby creating a primary knock-on atom (PKA) which, is considered as the onset of damage creation in the lattice. The PKA continues to undergo collisions with the lattice atoms which eventually leads to a collision cascade. In order to understand the collision process, one often simulates such systems using surrogate ions, such as energetic W ions itself, in particle accelerators and due to the experimental constraints (such as the stability of the beam) one often has to opt for high energetic ion beams (∼ 30 MeV) which surpasses the PKA energies created by neutron (∼100s of KeV) in W. Hence it is important to distinguish how the very high energetic tungsten atoms interact with the lattice atoms in comparison with the low energy PKA created by the neutron. One of the key difference is that at higher energies the electronic losses become important which decides the collision dynamics. In this presentation the effect of electronic losses in the damage creation using molecular dynamics simulations have been discussed

  14. Effect of proton and electron-irradiation intensity on radiation-induced damages in silicon bioolar transistors

    International Nuclear Information System (INIS)

    Bannikov, Yu.A.; Gorin, B.M.; Kozhevnikov, V.P.; Mikhnovich, V.V.; Gusev, L.I.

    1981-01-01

    The increase of radiation-induced damages of bipolar n-p-n transistors 8-12 times with the irradiation intensity decrease by protons from 4.07x1010 to 2.5x107 cm-2 x c-1 has been found experimentally. damages of p-n-p transistors vary in the opposite way - they are decreased 2-3 times with the irradiation intensity decrease within the same limits. the dependence of damages on intansity of proton irradiation occurs at the dose rate by three orders less than it has been observed for electron irradiation. the results obtained are explained by the dependence of radiation defectoformation reactions on charge state of defects with account for the role of formation of disordering regions upon proton irradiation [ru

  15. Recovery of damage in rad-hard MOS devices during and after irradiation by electrons, protons, alphas, and gamma rays

    Science.gov (United States)

    Brucker, G. J.; Van Gunten, O.; Stassinopoulos, E. G.; Shapiro, P.; August, L. S.; Jordan, T. M.

    1983-01-01

    This paper reports on the recovery properties of rad-hard MOS devices during and after irradiation by electrons, protons, alphas, and gamma rays. The results indicated that complex recovery properties controlled the damage sensitivities of the tested parts. The results also indicated that damage sensitivities depended on dose rate, total dose, supply bias, gate bias, transistor type, radiation source, and particle energy. The complex nature of these dependencies make interpretation of LSI device performance in space (exposure to entire electron and proton spectra) difficult, if not impossible, without respective ground tests and analyses. Complete recovery of n-channel shifts was observed, in some cases within hours after irradiation, with equilibrium values of threshold voltages greater than their pre-irradiation values. This effect depended on total dose, radiation source, and gate bias during exposure. In contrast, the p-channel shifts recovered only 20 percent within 30 days after irradiation.

  16. Discrimination of damages depending on the types of lactic dehydrogenase isozymes in electron beam irradiation

    International Nuclear Information System (INIS)

    Ohta, Akishige; Matsubayashi, Takashi; Liu Xiaolan; Takizawa, Haruki.

    1995-01-01

    Lactate dehydrogenase (EC 1.1.1.27,LDH) was a tetrameric molecule. The five different combinations of two different polypeptide chains can be readily identified by electrophoresis and ion-exchange chromatography. Injury patterns of LDH activity following electron-beam irradiation was investigated by assaying activities of three isozymes (pig heart LDH;M 4 , rabbit muscle LDH;H 4 , chicken heart LDH;M 3 H 1 ). Following results were obtained in the electron beam irradiation to three kinds of LDH isozymes: 1) Each isozyme has respective different reactivities to the electron beam irradiation. 2) Among the isozymes, M 4 enzyme was increased its enzymatic activity by the irradiations of low-level doses. 3) For the H 4 enzymes, an increasing phenomenon of -SH group was found in the low-level doses of electron beam irradiation. (author)

  17. Alternative approaches to electronic damage by ion-beam irradiation: Exciton models

    Energy Technology Data Exchange (ETDEWEB)

    Agullo-Lopez, F.; Munoz-Martin, A.; Zucchiatti, A. [Centro de Micro-Analisis de Materiales, Universidad Autonoma de Madrid, 28049, Madrid (Spain); Climent-Font, A. [Centro de Micro-Analisis de Materiales, Universidad Autonoma de Madrid, 28049, Madrid (Spain); Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, 28049, Madrid (Spain)

    2016-11-15

    The paper briefly describes the main features of the damage produced by swift heavy ion (SHI) irradiation. After a short revision of the widely used thermal spike concept, it focuses on cumulative mechanisms of track formation which are alternative to those based on lattice melting (thermal spike models). These cumulative mechanisms rely on the production of point defects around the ion trajectory, and their accumulation up to a final lattice collapse or amorphization. As to the formation of point defects, the paper considers those mechanisms relying on direct local conversion of the excitation energy into atomic displacements (exciton models). A particular attention is given to processes based on the non-radiative recombination of excitons that have become self-trapped as a consequence of a strong electron-phonon interaction (STEs). These mechanisms, although operative under purely ionizing radiation in some dielectric materials, have been rarely invoked, so far, to discuss SHI damage. They are discussed in this paper together with relevant examples to materials such as Cu{sub 3}N, alkali halides, SiO{sub 2}, and LiNbO{sub 3}. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Correlations for damage in diffused-junction InP solar cells induced by electron and proton irradiation

    International Nuclear Information System (INIS)

    Yamaguchi, M.; Takamoto, T.; Taylor, S.J.; Walters, R.J.; Summers, G.P.; Flood, D.J.; Ohmori, M.

    1997-01-01

    The damage to diffused-junction n + -p InP solar cells induced by electron and proton irradiations over a wide range of energy from 0.5 to 3 MeV and 0.015 to 20 MeV, respectively, has been examined. The experimental electron and proton damage coefficients have been analyzed in terms of displacement damage dose, which is the product of the particle fluence and the calculated nonionizing energy loss [G. P. Summers, E. A. Burke, R. Shapiro, S. R. Messenger, and R. J. Walters, IEEE Trans. Nucl. Sci. 40, 1300 (1993).] Degradation of InP cells due to irradiation with electrons and protons with energies of more than 0.5 MeV show a single curve as a function of displacement damage dose. Based on the deep-level transient spectroscopy analysis, damage equivalence between electron and proton irradiation is discussed. InP solar cells are confirmed to be substantially more radiation resistant than Si and GaAs-on-Ge cells. copyright 1997 American Institute of Physics

  19. Radiation damage of multipixel Geiger-mode avalanche photodiodes irradiated with low-energy γ's and electrons

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Y.; Yun, Y. B. [Yonsei University, Seoul (Korea, Republic of); Ha, J. M. [Yonsei University, Seoul (Korea, Republic of); Electronics and Telecommunications Research Institute, Daejeon (Korea, Republic of); Lee, J. S.; Yoon, Y. S. [Electronics and Telecommunications Research Institute, Daejeon (Korea, Republic of); Eun, J. W. [Namseoul University, Cheonan (Korea, Republic of)

    2012-05-15

    A few types of multipipixel Geiger-mode avalanche photodiodes (also referred to as silicon photomultipliers SiPMs) are irradiated with 1 to 2.5 MeV γ's and electrons. We characterize radiation damage effects appearing in the reverse bias current, the dark current and count rate, the pixel gain, and the photon detection efficiency of the devices. An interesting observation on the dark current and count rate is made and linked to the specific damage caused by the irradiation.

  20. Vascular damage after acute local irradiation: a light and electron microscope study

    International Nuclear Information System (INIS)

    Verola, O.; Brocheriou, C.

    1986-01-01

    A pig model was used to examine histological and ultrastructural changes after high-dose local irradiation. This model was chosen to simulate accidents which have occurred in man, enabling the determination of several post-irradiation phases. After an initial phase, with superficial lesions, ischaemic necrosis occurred 3 weeks after irradiation as the result of early vascular alterations. After 2 months, expanding necrosis became obvious in the deep muscle, preceded by an initial spread of vascular lesions: these alterations were obvious from the 30th day by light microscopy but could be detected by electron microscopy from the 9th day. (author)

  1. Neutron irradiation damage of nuclear graphite studied by high-resolution transmission electron microscopy and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Krishna, R. [Dalton Cumbrian Facility, Dalton Nuclear Institute, The University of Manchester, Westlakes Science & Technology Park, Moor Row, Whitehaven, Cumbria, CA24 3HA (United Kingdom); Jones, A.N., E-mail: Abbie.Jones@manchester.ac.uk [Nuclear Graphite Research Group, School of MACE, The University of Manchester, Manchester, M13 9PL (United Kingdom); McDermott, L.; Marsden, B.J. [Nuclear Graphite Research Group, School of MACE, The University of Manchester, Manchester, M13 9PL (United Kingdom)

    2015-12-15

    Nuclear graphite components are produced from polycrystalline artificial graphite manufacture from a binder and filler coke with approximately 20% porosity. During the operational lifetime, nuclear graphite moderator components are subjected to fast neutron irradiation which contributes to the change of material and physical properties such as thermal expansion co-efficient, young's modulus and dimensional change. These changes are directly driven by irradiation-induced changes to the crystal structure as reflected through the bulk microstructure. It is therefore of critical importance that these irradiation changes and there implication on component property changes are fully understood. This work examines a range of irradiated graphite samples removed from the British Experimental Pile Zero (BEPO) reactor; a low temperature, low fluence, air-cooled Materials Test Reactor which operated in the UK. Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM) have been employed to characterise the effect of increased irradiation fluence on graphite microstructure and understand low temperature irradiation damage processes. HRTEM confirms the structural damage of the crystal lattice caused by irradiation attributed to a high number of defects generation with the accumulation of dislocation interactions at nano-scale range. Irradiation-induced crystal defects, lattice parameters and crystallite size compared to virgin nuclear graphite are characterised using selected area diffraction (SAD) patterns in TEM and Raman Spectroscopy. The consolidated ‘D’peak in the Raman spectra confirms the formation of in-plane point defects and reflected as disordered regions in the lattice. The reduced intensity and broadened peaks of ‘G’ and ‘D’ in the Raman and HRTEM results confirm the appearance of turbulence and disordering of the basal planes whilst maintaining their coherent layered graphite structure. - Highlights: • Irradiated graphite

  2. Neutron irradiation damage of nuclear graphite studied by high-resolution transmission electron microscopy and Raman spectroscopy

    International Nuclear Information System (INIS)

    Krishna, R.; Jones, A.N.; McDermott, L.; Marsden, B.J.

    2015-01-01

    Nuclear graphite components are produced from polycrystalline artificial graphite manufacture from a binder and filler coke with approximately 20% porosity. During the operational lifetime, nuclear graphite moderator components are subjected to fast neutron irradiation which contributes to the change of material and physical properties such as thermal expansion co-efficient, young's modulus and dimensional change. These changes are directly driven by irradiation-induced changes to the crystal structure as reflected through the bulk microstructure. It is therefore of critical importance that these irradiation changes and there implication on component property changes are fully understood. This work examines a range of irradiated graphite samples removed from the British Experimental Pile Zero (BEPO) reactor; a low temperature, low fluence, air-cooled Materials Test Reactor which operated in the UK. Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM) have been employed to characterise the effect of increased irradiation fluence on graphite microstructure and understand low temperature irradiation damage processes. HRTEM confirms the structural damage of the crystal lattice caused by irradiation attributed to a high number of defects generation with the accumulation of dislocation interactions at nano-scale range. Irradiation-induced crystal defects, lattice parameters and crystallite size compared to virgin nuclear graphite are characterised using selected area diffraction (SAD) patterns in TEM and Raman Spectroscopy. The consolidated ‘D’peak in the Raman spectra confirms the formation of in-plane point defects and reflected as disordered regions in the lattice. The reduced intensity and broadened peaks of ‘G’ and ‘D’ in the Raman and HRTEM results confirm the appearance of turbulence and disordering of the basal planes whilst maintaining their coherent layered graphite structure. - Highlights: • Irradiated graphite exhibits

  3. Displacement damage analysis and modified electrical equivalent circuit for electron and photon-irradiated silicon solar cells

    Science.gov (United States)

    Arjhangmehr, Afshin; Feghhi, Seyed Amir Hossein

    2014-10-01

    Solar modules and arrays are the conventional energy resources of space satellites. Outside the earth's atmosphere, solar panels experience abnormal radiation environments and because of incident particles, photovoltaic (PV) parameters degrade. This article tries to analyze the electrical performance of electron and photon-irradiated mono-crystalline silicon (mono-Si) solar cells. PV cells are irradiated by mono-energetic electrons and poly-energetic photons and immediately characterized after the irradiation. The mean degradation of the maximum power (Pmax) of silicon solar cells is presented and correlated using the displacement damage dose (Dd) methodology. This method simplifies evaluation of cell performance in space radiation environments and produces a single characteristic curve for Pmax degradation. Furthermore, complete analysis of the results revealed that the open-circuit voltage (Voc) and the filling factor of mono-Si cells did not significantly change during the irradiation and were independent of the radiation type and fluence. Moreover, a new technique is developed that adapts the irradiation-induced effects in a single-cell equivalent electrical circuit and adjusts its elements. The "modified circuit" is capable of modeling the "radiation damage" in the electrical behavior of mono-Si solar cells and simplifies the designing of the compensation circuits.

  4. Radiation damage in uranium under electron irradiation of energies up to 20 MeV

    International Nuclear Information System (INIS)

    Emets, N.L.; Zelenskij, V.F.; Kuz'menko, V.A.; Ranyuk, Yu.N.; Reznichenko, Eh.A.; Shilyaev, B.A.; Yamnitskij, V.A.

    1980-01-01

    The problem of conservation of primary radiation-induced defects in uranium irradiated by electrons with the energy exceeding photo fission threshold is considered. Calculation of uranium burnout is carried out. Calculations are conducted by the method of mathematical simulation, using some nuclear models; development of electromagnetic cascade in uranium, photofission process, elastic and inelastic electron scattering, as well as some secondary processes are taken into account. Proved is the fact of anomalous growth of uranium under electron irradiation, registered earlier experimentally. It is shown, that in case of acquiring the value Ed=15 eV radiation uranium growth at low levels of burnout can be explained by the complete capture of all the primary radiationn-induced defects into dislocation loops [ru

  5. Effect of electron-excitation on radiation damage in ion-irradiated FCC metals

    International Nuclear Information System (INIS)

    Iwase, Akihiro

    1989-06-01

    FCC metals (Al, Cu, Ag, Ni) were irradiated with 0.5-1.8 MeV H, He, N and Ar ions, and 84-126 MeV C, F, Si, Cl, Br and I ions at liquid helium temperatures. After the irradiations, thermal annealing experiments were performed up to 300 K. Anomalous reduction of Stage-I recovery was observed in Al and Ni irradiated with high-energy (∼100 MeV) heavy ions. Radiation annealing by 100 MeV I ions was studied in predoped Ni and Cu. The experimental results were analyzed by using a new model which describes the production and radiation annealing of two or more types of defects. The extraordinarily large cross sections for subthreshold recombination of Stage-I defects were obtained in Ni. These results show that in Al and Ni, the energies transferred from the excited electrons to lattice through the electron-lattice interaction contribute to the annihilations of defects during irradiation. (author)

  6. Radiation damage measurements on nonmetals made during irradiation with 1 to 3 MeV electrons. Final Report

    International Nuclear Information System (INIS)

    Levy, P.W.

    1982-01-01

    To investigate the fundamental processes producing radiation damage in nonmetals a unique facility has been developed for making optical absorption, luminescence and other measurements during irradiation with 1 to 3 MeV electrons. Measurements are made with a 13 meter long double beam spectrometer arranged so that all sensitive components, e.g., phototubes, are outside of the irradiation chamber. A computer provdies automatic control and data recording. A 256 point absorption and a 256 point luminescence spectra are recorded as often as every 40 seconds in either the 200-400 or 400-800 mm wavelength range. Samples are irradiated, at temperatures between 20 and 900 C, in an electronically controlled chamber containing He exchange gas and equipped with thin Havar windows to transmit the electron beam and high purity fused silica windows for the spectrophotometer beams. Radiation induced luminescence and absorption in the chamber windows, etc. is eliminated by the double beam spectrophotometer. Studies made with this equipment demonstrate clearly that many of the processes occurring during damage formation are transient

  7. Irradiation damage of II-VI compounds in a high-voltage electron microscope

    International Nuclear Information System (INIS)

    Yoshiie, T.; Iwanaga, H.; Shibata, N.; Suzuki, K.; Ichihara, M.; Takeuchi, S.

    1983-01-01

    Dislocation loops produced by electron irradiation in a 1 MV electron microscope have been studied above room temperature for five II-VI compounds: CdS and ZnO, with the wurtzite structure, and CdTe, ZnSe and ZnS, with the zincblende structure. For all the crystals the density of loops decreased as the irradiation temperature increased, until no loops were produced above a certain temperature which varied from crystal to crystal. However, the loop density did not depend on the electron flux intensity, suggesting the heterogeneous nucleation at some impurity complex of equilibrium concentration. Diffraction contrast analyses showed that the loops are of interstitial type in each crystal, with Burgers vectors as follows: 1/2[0001] and 1/3 for wurtzite crystals, the density ratio of the former type to the latter being increased with increasing temperature; mostly 1/3 and a few 1/2 for zincblende crystals, the latter type being presumably formed as a result of unfaulting in the former. An effect of crystal polarity on the shape of the loops in zincblende crystals has been observed. (author)

  8. Analysis of radiation damage to Si solar cells under high-fluence electron irradiation

    International Nuclear Information System (INIS)

    Yamaguchi, Masafumi; Taylor, S.J.; Yang, Ming-Ju; Matsuda, Sumio; Kawasaki, Osamu; Hisamatsu, Tadashi.

    1996-01-01

    Radiation testing of Si n + -p-p + space solar cells has revealed an anomalous increase in short-circuit current I sc , followed by an abrupt decrease and cell failure, induced by high-fluence (>10 16 cm -2 ) electron irradiation. A model which can be used to explain these phenomena by expressing the change in majority-carrier concentration p of the base region as a function of the electron fluence has been proposed in addition to the well-known model in which I sc is decreased due to minority-carrier lifetime reduction with irradiation. The reduction in p due to majority-carrier trapping by radiation-induced defects has two effects; one is broadening of the depletion layer which contributes to the increase in the generated photocurrent and that in the recombination-generation current in the depletion layer, and the second is an increase in the resistivity of the base layer resulting in an abrupt decrease of I sc and failure of the solar cells. (author)

  9. Radiation-induced damage and recovery effects in GG17 glass irradiated by 1 MeV electrons

    International Nuclear Information System (INIS)

    Wang Qingyan; Zhang Zhonghua; Geng Hongbin; Sun Chengyue; Yang Dezhuang; He Shiyu; Hu Zhaochu

    2012-01-01

    The optical properties and microstructural damage of GG17 glasses, as well as their recovery during annealing at room temperature, are investigated after exposure to 1 MeV electrons with various fluences. Experimental results show that the electrons lead to severe optical degradation in the GG17 glass, and induce the formation of paramagnetic defects which can be mainly attributed to the boron–oxygen hole centers. With increasing annealing time at room temperature their decay serves as long-lived defects following first order kinetics. Except for the strong absorption bands located at 334–352 nm and 480 nm that corresponds to the boron–oxygen hole centers, weaker absorption bands appear at 780 nm or 794.6 nm after irradiation, inducing a decrease in transmittance by approximately 17% for a fluence of 1 × 10 16 cm −2 . It is shown that electron irradiation could cause a harmful effect on rubidium lamps when GG17 glass is used as the lamp envelope material.

  10. Irradiation damage in superconductors

    International Nuclear Information System (INIS)

    Quere, Y.

    1989-01-01

    Most superconductors are quite sensitive to irradiation defects. Critical temperatures may be depressed, critical currents may be increased, by irradiation, but other behaviours may be encountered. In compounds, the sublattice in which defects are created is of significant importance. 24 refs

  11. Electron beam irradiating device

    Energy Technology Data Exchange (ETDEWEB)

    Shinohara, K

    1969-12-20

    The efficiency of an electron beam irradiating device is heightened by improving the irradiation atmosphere and the method of cooling the irradiation window. An irradiation chamber one side of which incorporates the irradiation windows provided at the lower end of the scanner is surrounded by a suitable cooling system such as a coolant piping network so as to cool the interior of the chamber which is provided with circulating means at each corner to circulate and thus cool an inert gas charged therewithin. The inert gas, chosen from a group of such gases which will not deleteriously react with the irradiating equipment, forms a flowing stream across the irradiation window to effect its cooling and does not contaminate the vacuum exhaust system or oxidize the filament when penetrating the equipment through any holes which the foil at the irradiation window may incur during the irradiating procedure.

  12. Multispecimen dual-beam irradiation damage chamber

    International Nuclear Information System (INIS)

    Packan, N.H.; Buhl, R.A.

    1980-06-01

    An irradiation damage chamber that can be used to rapidly simulate fast neutron damage in fission or fusion materials has been designed and constructed. The chamber operates in conjunction with dual Van de Graaff accelerators at ORNL to simulate a wide range of irradiation conditions, including pulsed irradiation. Up to six experiments, each with up to nine 3-mm disk specimens, can be loaded into the ultrahigh vacuum chamber. Specimen holders are heated with individual electron guns, and the temperature of each specimen can be monitored during bombardment by an infrared pyrometer. Three different dose levels may be obtained during any single bombardment, and the heavy-ion flux on each of the nine specimens can be measured independently with only a brief interruption of the beam. The chamber has been in service for nearly three years, during which time approximately 250 bombardments have been successfully carried out. An appendix contains detailed procedures for operating the chamber

  13. Unusual surface and edge morphologies, sp2 to sp3 hybridized transformation and electronic damage after Ar+ ion irradiation of few-layer graphene surfaces.

    Science.gov (United States)

    Al-Harthi, Salim Hamood; Elzain, Mohammed; Al-Barwani, Muataz; Kora'a, Amal; Hysen, Thomas; Myint, Myo Tay Zar; Anantharaman, Maliemadom Ramaswamy

    2012-08-19

    Roughness and defects induced on few-layer graphene (FLG) irradiated by Ar+ ions at different energies were investigated using X-ray photoemission spectroscopy (XPS) and atomic force microscopy techniques. The results provide direct experimental evidence of ripple formation, sp2 to sp3 hybridized carbon transformation, electronic damage, Ar+ implantation, unusual defects and edge reconstructions in FLG, which depend on the irradiation energy. In addition, shadowing effects similar to those found in oblique-angle growth of thin films were seen. Reliable quantification of the transition from the sp2-bonding to sp3-hybridized state as a result of Ar+ ion irradiation is achieved from the deconvolution of the XPS C (1s) peak. Although the ion irradiation effect is demonstrated through the shape of the derivative of the Auger transition C KVV spectra, we show that the D parameter values obtained from these spectra which are normally used in the literature fail to account for the sp2 to sp3 hybridization transition. In contrast to what is known, it is revealed that using ion irradiation at large FLG sample tilt angles can lead to edge reconstructions. Furthermore, FLG irradiation by low energy of 0.25 keV can be a plausible way of peeling graphene layers without the need of Joule heating reported previously.

  14. Precise measurements of spatial density distributions of damages introduced into GaP by MeV-electron beam irradiations based on its optical properties

    International Nuclear Information System (INIS)

    Endo, T.; Hashimoto, Y.; Nakanishi, Y.; Wada, T.

    1985-01-01

    GaP crystals were irradiated uniformly on their flat surfaces by 10 MeV-electrons. The 'below-gap' absorption coefficient Δαsub(b)(hν) and the normalized white-light optical density D/d in these samples increased linearly with a dose phi as Δαsub(b)(2.0) = 3.3 x 10 -16 phi and D/d = 1.42 x 10 -16 phi. The free electron density n in the conduction band estimated from the X 1 -> X 3 absorption band decreased with phi, and as the decrease in the free electron density Δn is equivalent to the density of introduced defects N, it could be expressed that N = Δn = Rsub(c)phi where the value of the carrier removal rate Rsub(c) was 5.8 cm -1 for the S-doped sample. These expressions lead to the basic relation that N is proportional to D/d as expressed in N = 4.1 x 10 16 D/d. Two-dimensional distributions of D/d were measured in the samples irradiated by collimated electron beams at 10 and 16 MeV by using a microdensitometer, and they were converted into the two-dimensional distributions of damage density according to the linear relation of N-D/d. Damages gradually spread laterally with increasing depth at first and then shrink. (author)

  15. Splitting diffraction peak in different thickness LL-interferometer and determination of thickness of damaged layer induced by electron irradiation of plates

    International Nuclear Information System (INIS)

    Truni, K.G.; Sedrakyan, A.G.; Papoyan, A.A.; Bezirganyan, P.A.

    1988-01-01

    Amplitude of twice reflected beam is calculated analytically, oscillatory dependence of peak intensity in the centre of diffraction image on the small variations in thickness is shown. The expression, clearly binding the splitting value of diffraction peak with variation in thickness of the interferometer plates, is received. The effect of variation in thickness on the splitting value of focal line is studied experimentally in case of irradiation of the equal-arm Π-shaped interferometer blocks by fast electron flow, thickness of the originated damaged layers are determined

  16. Lattice damage caused by the irradiation of diamond

    CERN Document Server

    Campbell, B; Mainwood, A; Newton, M; Davies, G

    2002-01-01

    Diamond is perceived to be radiation-hard, but the damage caused to the diamond is not well understood. The intrinsic defects (vacancies and interstitials) which are created by radiation damage are immobile at room temperature in diamond, unlike in silicon. Therefore, once the mechanisms of damage are understood for one type and energy of the particle, the dose and energy dependence of irradiation by other particles at a range of energies can be extrapolated. When a crystal is irradiated, the generation rates of vacancies and self-interstitials are generally determined by optical or electron paramagnetic resonance (EPR) spectroscopy experiments carried out after the irradiation has stopped. However, as the irradiation proceeds some of the carbon atoms displaced from their lattice sites may relax back into the vacant site, and the damage event will not be observed in the later measurement. In this paper, the mechanisms for radiation damage by charged particles in particular electrons and photons are investigat...

  17. Spectroscopy of electron irradiated polymers in electron microscope

    International Nuclear Information System (INIS)

    Faraj, S.H.; Salih, S.M.

    1981-01-01

    The damage induced by energetic electrons in the course of irradiation of polymers in a transmission electron microscope was investigated spectroscopically. Damage on the molecular level has been detected at very low exposure doses. These effects have been induced by electron doses less than that received by the specimen when it is situated at its usual place of the specimen stage in the electron microscope by a factor of 1,000. (author)

  18. Electron irradiation of zeolites

    International Nuclear Information System (INIS)

    Wang, S.X.; Wang, L.M.; Ewing, R.C.

    1999-01-01

    Three different zeolites (analcime, natrolite, and zeolite-Y) were irradiated with 200 keV and 400 keV electrons. All zeolites amorphized under a relatively low electron fluence. The transformation from the crystalline-to-amorphous state was continuous and homogeneous. The electron fluences for amorphization of the three zeolites at room temperature were: 7.0 x 10 19 e - /cm 2 (analcime), 1.8 x 10 20 e - /cm 2 (natrolite), and 3.4 x 10 20 e - /cm 2 (zeolite-Y). The different susceptibilities to amorphization are attributed to the different channel sizes in the structures which are the pathways for the release of water molecules and Na + . Natrolite formed bubbles under electron irradiation, even before complete amorphization. Analcime formed bubbles after amorphization. Zeolite-Y did not form bubbles under irradiation. The differences in bubble formation are attributed to the different channel sizes of the three zeolites. The amorphization dose was also measured at different temperatures. An inverse temperature dependence of amorphization dose was observed for all three zeolites: electron dose for amorphization decreased with increasing temperature. This unique temperature effect is attributed to the fact that zeolites are thermally unstable. A semi-empirical model was derived to describe the temperature effect of amorphization in these zeolites

  19. Radiation damage of uranium-thorium oxide, irradiated in water

    International Nuclear Information System (INIS)

    Bloem, P.J.C.; Nagel, W.; Plas, T. van der; Kema, N.V.

    1977-01-01

    A suspension in water of spherical particles of UO 2 -ThO 2 with diameter 5μm has been considered as the working fluid in an aqueous, homogeneous, thermal nuclear reactor. Irradiation experiments have shown that these particles suffer a gradual breakdown when irradiated in water. This behaviour is markedly different from that shown on irradiation in absence of water. As damage was defined the amount of solid dissolved by an etching liquid. Electron microscopic pictures showed that at higher irradiation temperatures in water the actual damage was larger than the etching values indicated. (orig.) [de

  20. Sewage sludge irradiation with electrons

    International Nuclear Information System (INIS)

    Tauber, M.

    1976-01-01

    The disinfection of sewage sludge by irradiation has been discussed very intensively in the last few months. Powerful electron accelerators are now available and the main features of the irradiation of sewage sludge with fast electrons are discussed and the design parameters of such installations described. AEG-Telefunken is building an irradiation plant with a 1.5 MeV, 25 mA electron accelerator, to study the main features of electron irradiation of sewage sludge. (author)

  1. Neutron irradiation damage in transition metal carbides

    International Nuclear Information System (INIS)

    Matsui, Hisayuki; Nesaki, Kouji; Kiritani, Michio

    1991-01-01

    Effects of neutron irradiation on the physical properties of light transition metal carbides, TiC x , VC x and NbC x , were examined, emphasizing the characterization of irradiation induced defects in the nonstoichiometric composition. TiC x irradiated with 14 MeV (fusion) neutrons showed higher damage rates with increasing C/Ti (x) ratio. A brief discussion is made on 'cascade damage' in TiC x irradiated with fusion neutrons. Two other carbides (VC x and NbC x ) were irradiated with fission reactor neutrons. The irradiation effects on VC x were not so simple, because of the complex irradiation behavior of 'ordered' phases. For instance, complete disordering was revealed in an ordered phase, 'V 8 C 7 ', after an irradiation dose of 10 25 n/m 2 . (orig.)

  2. Damage nucleation in Si during ion irradiation

    International Nuclear Information System (INIS)

    Holland, O.W.; Fathy, D.; Narayan, J.

    1984-01-01

    Damage nucleation in single crystals of silicon during ion irradiation is investigated. Experimental results and mechanisms for damage nucleation during both room and liquid nitrogen temperature irradiation with different mass ions are discussed. It is shown that the accumulation of damage during room temperature irradiation depends on the rate of implantation. These dose rate effects are found to decrease in magnitude as the mass of the ions is increased. The significance of dose rate effects and their mass dependence on nucleation mechanisms is discussed

  3. Damages to gladiolu corm caused by fast neutron irradiation

    International Nuclear Information System (INIS)

    Zhang Zhiwei; Wang Dan; Zhang Dongxue; Zheng Chun

    2007-01-01

    Gladiolus corms were irradiated to 100-500kGy by fast neutrons in the CFBR-II pulsed reactor, Scanning electron microscope images of the irradiated samples revealed significant radiation damages to the gladiolus corms, and the mutagenic effects were studied by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Within the dose range, radiation damage to the corm increased with the dose, with corm epidermis of the samples irradiated in vertical incidence being more serious than those irradiated in side-incidence to the same dose. Biological characters were investigated via field experiments, and the bands of protein subunit were analyzed by SDS-PAGE. The results showed that the fast neutrons irradiation inhibited growth of M1 generation seedling significantly. Protein expression was obviously inhibited by the irradiation. The study indicates that fast neutron induction is an effective way for gladiolus breeding. And the results may lay a foundation for studies on fast neutron mutation breeding. (authors)

  4. Effect of dose rate, temperature and impurity content on the radiation damage in the electron irradiated NaCl crystals

    NARCIS (Netherlands)

    Dubinko, V.I.; Turkin, A.A.; Vainshtein, D.I.; Hartog, H.W. den

    The dependencies of void formation and radiolytic sodium accumulation on the irradiation dose, dose rate, temperature and impurity content are analyzed within a framework of a theoretical model, which is based on a new mechanism of dislocation climb. The mechanism involves the production of V-F

  5. Cytometric analysis of irradiation damaged chromosomes

    International Nuclear Information System (INIS)

    Wilder, M.E.; Raju, M.R.

    1982-01-01

    Irradiation of cells in interphase results in dose-dependent damage to DNA which is discernable by flow-cytometric analysis of chromosomes. The quantity (and possibly the quality) of chromosomal changes is different in survival-matched doses of x and α irradiation. It may, therefore, be possible to use these methods for analysis of dose and type of exposure in unknown cases

  6. Damage and fatigue crack growth of Eurofer steel first wall mock-up under cyclic heat flux loads. Part 1: Electron beam irradiation tests

    Energy Technology Data Exchange (ETDEWEB)

    You, J.H., E-mail: you@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, Euratom Association, Boltzmannstr. 2, 85748 Garching (Germany); Höschen, T. [Max-Planck-Institut für Plasmaphysik, Euratom Association, Boltzmannstr. 2, 85748 Garching (Germany); Pintsuk, G. [Forschungszentrum Jülich GmbH, IEK2, Euratom Association, 52425 Jülich (Germany)

    2014-04-15

    Highlights: • Clear evidence of microscopic damage and crack formation at the notch root in the early stage of the fatigue loading (50–100 load cycles). • Propagation of fatigue crack at the notch root in the course of subsequent cyclic heat-flux loading followed by saturation after roughly 600 load cycles. • No sign of damage on the notch-free surface up to 800 load cycles. • No obvious effect of the pulse time duration on the crack extension. • Slight change in the grain microstructure due to the formation of sub-grain boundaries by plastic deformation. - Abstract: Recently, the idea of bare steel first wall (FW) is drawing attention, where the surface of the steel is to be directly exposed to high heat flux loads. Hence, the thermo-mechanical impacts on the bare steel FW will be different from those of the tungsten-coated one. There are several previous works on the thermal fatigue tests of bare steel FW made of austenitic steel with regard to the ITER application. In the case of reduced-activation steel Eurofer97, a candidate structural material for the DEMO FW, there is no report on high heat flux tests yet. The aim of the present study is to investigate the thermal fatigue behavior of the Eurofer-based bare steel FW under cyclic heat flux loads relevant to DEMO operation. To this end, we conducted a series of electron beam irradiation tests with heat flux load of 3.5 MW/m{sup 2} on water-cooled mock-ups with an engraved thin notch on the surface. It was found that the notch root region exhibited a marked development of damage and fatigue cracks whereas the notch-free surface manifested no sign of crack formation up to 800 load cycles. Results of extensive microscopic investigation are reported.

  7. Electron damage in organic crystals

    International Nuclear Information System (INIS)

    Howitt, D.G.; Thomas, G.

    1977-01-01

    The effects of radiation damage in three crystalline organic materials (l-valine, cytosine, copper phthalocyanine) have been investigated by electron microscopy. The degradation of these materials has been found to be consistent with a gradual collapse of their crystal structures brought about by ionization damage to the comprising molecules. It is inferred that the crystallinity of these materials is destroyed by ionizing radiation because the damaged molecules cannot be incorporated into the framework of their original structures. (author)

  8. Irradiation damage to the lung

    International Nuclear Information System (INIS)

    Fennessy, J.J.

    1987-01-01

    While some degree of injury to normal, non-tumor-bearing, intrathoracic structures always occurs following irradiation for cure or palliation of neoplastic disease, clinical expression of this injury is uncommon. However, under certain circumstances, clinical manifestations may be severe and life threatening. Acute radiographic manifestations of pulmonary injury usually appear either synchronous with or, more typically, seven to ten days after the onset of the clinical syndrome. The acute signs of edema and slight volume loss within the irradiated zone are nonspecific except for their temporal and spatial relationship to the irradiation of the patient. Resolution of the acute changes is followed by pulmonary cicatrization, which is almost always stable within one year after completion of therapy. Change in postirradiation scarring following stabilization of the reaction must always be assumed to be due to some other process. While the radiograph primarily reveals pulmonary injury, all tissues, including the heart and major vessels, are susceptible, and the radiologist must recognize that any change within the thorax of a patient who has undergone thoracic irradiation may be a complication of that treatment. Differentiation of irradiation injury from residual or recurrent tumor, drug reaction, or opportunistic infection may be difficult and at times impossible

  9. Electron irradiation of power transistors

    International Nuclear Information System (INIS)

    Hower, P.L.; Fiedor, R.J.

    1982-01-01

    A method for reducing storage time and gain parameters in a semiconductor transistor includes the step of subjecting the transistor to electron irradiation of a dosage determined from measurements of the parameters of a test batch of transistors. Reduction of carrier lifetime by proton bombardment and gold doping is mentioned as an alternative to electron irradiation. (author)

  10. Facilities for studying radiation damage in nonmetals during irradiation

    International Nuclear Information System (INIS)

    Levy, P.W.

    1984-08-01

    Two facilities have been developed for making optical absorption, luminescence and other measurements on a single sample before, during and after irradiation. One facility uses 60 Co gamma rays and the other 0.5 to 3 MeV electrons from an accelerator. Optical relays function as spectrophotometers, luminescenc detectors, etc. All radiation sensitive components are outside of walk-in irradiation chambers; all measurement control and data recording is computerized. Irradiations are made at controlled temperatures between 5K and 900 0 C. The materials studied include glasses, quartz, alkali halides (especially natural rock salt), organic crystals, etc. As determined from color center measurements the damage formation rate in all materials studied at 25 0 C or above is strongly temperature dependent. The defect concentration during irradiation is usually much greater than that measured after irradiation. The fraction of defects annealing after irradiation and the annealing rate usually increases as the irradiation temperature increases. The completed studies demonstrate that, in most cases, the extent of maximum damage and the damage formation and annealing kinetics can be determined only by making measurements during irradiation

  11. Damage of lymphocytes by ionizing irradiation

    International Nuclear Information System (INIS)

    Rose, H.; Moldenhauer, H.; Kehrberg, G.

    1985-01-01

    After a short review, how lymphocytes of the peripheral blood are influenced by radiotherapy, the damage of lymphocytes by whole-body irradiation is pointed out in animal experiments and after in vitro irradiation. The special sensibility of B-cells and their homogeneity in fields of radiobiology are opposed to the heterogeneity of T-cells. The radiosensibility of cytotoxic lymphocytes, suppressor cells, and helper cells are discussed. It appears, that within these functional criteria, there is a different radiosensibility, too. (author)

  12. DNA damage induced by radionuclide internal irradiation

    International Nuclear Information System (INIS)

    Cui Fengmei; Zhao Jingyong; Hong Chengjiao; Lao Qinhua; Wang Liuyi; Yang Shuqin

    2004-01-01

    Objective: To study the DNA damage of peripheral blood mononuclear cell (PBMC) in rats exposed to radionuclide internal irradiation. Methods: The radionuclides were injected into the rats and single cell get electrophoresis (SCGE) was performed to detect the length of DNA migration in the rat PBMC. Results: DNA migration in the rat PBMC increased with accumulative dose or dose-rate. It showed good relationship of dose vs. response and of dose-rate vs. response, both relationship could be described as linear models. Conclusion: Radionuclide internal irradiation could cause DNA damage in rat PBMC. (authors)

  13. Study of damages by neutron irradiation in lithium aluminates

    International Nuclear Information System (INIS)

    Palacios G, O.

    1999-01-01

    Lithium aluminates proposed to the production of tritium in fusion nuclear reactors, due to the thermal stability that they present as well as the behavior of the aluminium to the irradiation. As a neutron flux with profile (≅ 14 Mev) of a fusion reactor is not available. A irradiation experiment was designed in order to know the micro and nano structure damages produced by fast and thermal neutrons in two irradiation positions of the fusion nuclear reactor Triga Mark III: CT (Thermal Column) and SIFCA (System of Irradiation Fixed of Capsules). In this work samples of lithium aluminate were characterized by XRD (X-Ray Diffraction), TEM (Transmission Electron Microscopy) and SEM (Scanning Electron Microscopy). Two samples were prepared by two methods: a) coalition method and b) peroxide method. This characterization comprised original and irradiated samples. The irradiated sample amounted to 4 in total: one for each preparation method and one for each irradiation position. The object of this analysis was to correlate with the received neutron dose the damages suffered by the samples with the neutron irradiation during long periods (440 H), in their micro and nano structure aspects; in order to understand the changes as a function of the irradiation zone (with thermal and fast neutron flux) and the preparation methods of the samples and having as an antecedent the irradiation in SIFCA position by short times (2h). The obtained results are referred to the stability of γ -aluminate phase, under given conditions of irradiation and defined nano structure arrangement. They also refer to the proposals of growth mechanism and nucleation of new phases. The error associated with the measurement of neutron dose is also discussed. (Author)

  14. Irradiation damage of SiC semiconductor device (I)

    International Nuclear Information System (INIS)

    Park, Ji Yeon; Kim, Weon Ju

    2000-09-01

    This report reviewed the irradiation damage of SiC semiconductor devices and examined a irradiation behavior of SiC single crystal as a pre-examination for evaluation of irradiation behavior of SiC semiconductor devices. The SiC single was crystal irradiated by gamma-beam, N+ ion and electron beam. Annealing examinations of the irradiated specimens also were performed at 500 deg C. N-type 6H-SiC dopped with N+ ion was used and irradiation doses of gamma-beam, N+ion and electron beam were up to 200 Mrad, 1x10 16 N + ions/cm 2 and 3.6 x 10 17 e/cm 2 and 1.08 x 10 18 e/cm 2 , respectively. Irradiation damages were analyzed by the EPR method. Additionally, properties of SiC, information about commercial SiC single crystals and the list of web sites with related to the SiC device were described in the appendix

  15. Irradiation damage of SiC semiconductor device (I)

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Yeon; Kim, Weon Ju

    2000-09-01

    This report reviewed the irradiation damage of SiC semiconductor devices and examined a irradiation behavior of SiC single crystal as a pre-examination for evaluation of irradiation behavior of SiC semiconductor devices. The SiC single was crystal irradiated by gamma-beam, N+ ion and electron beam. Annealing examinations of the irradiated specimens also were performed at 500 deg C. N-type 6H-SiC dopped with N+ ion was used and irradiation doses of gamma-beam, N+ion and electron beam were up to 200 Mrad, 1x10{sup 16} N{sup +} ions/cm{sup 2} and 3.6 x 10{sup 17} e/cm{sup 2} and 1.08 x 10{sup 18} e/cm{sup 2} , respectively. Irradiation damages were analyzed by the EPR method. Additionally, properties of SiC, information about commercial SiC single crystals and the list of web sites with related to the SiC device were described in the appendix.

  16. Krypton irradiation damage in Nd-doped zirconolite and perovskite

    International Nuclear Information System (INIS)

    Davoisne, C.; Stennett, M.C.; Hyatt, N.C.; Peng, N.; Jeynes, C.; Lee, W.E.

    2011-01-01

    Understanding the effect of radiation damage and noble gas accommodation in potential ceramic hosts for plutonium disposition is necessary to evaluate their long-term behaviour during geological disposal. Polycrystalline samples of Nd-doped zirconolite and Nd-doped perovskite were irradiated ex situ with 2 MeV Kr + at a dose of 5 x 10 15 ions cm -2 to simulate recoil of Pu nuclei during alpha decay. The feasibility of thin section preparation of both pristine and irradiated samples by Focused Ion Beam sectioning was demonstrated. After irradiation, the Nd-doped zirconolite revealed a well defined amorphous region separated from the pristine material by a thin (40-60 nm) damaged interface. The zirconolite lattice was lost in the damaged interface, but the fluorite sublattice was retained. The Nd-doped perovskite contained a defined irradiated layer composed of an amorphous region surrounded by damaged but still crystalline layers. The structural evolution of the damaged regions is consistent with a change from orthorhombic to cubic symmetry. In addition in Nd-doped perovskite, the amorphisation dose depended on crystallographic orientation and possibly sample configuration (thin section or bulk). Electron Energy Loss Spectroscopy revealed Ti remained in the 4+ oxidation state but there was a change in Ti coordination in both Nd-doped perovskite and Nd-doped zirconolite associated with the crystalline to amorphous transition.

  17. Radiation damage in heavy irradiated aluminum nitride

    International Nuclear Information System (INIS)

    Atobe, Kozo; Honda, Makoto; Fukuoka, Noboru; Okada, Moritami; Nakagawa, Masuo.

    1996-01-01

    AlN, one of candidate for ceramic materials used in nuclear fusion reactor, was irradiated by fast and thermal neutrons. The high concentration of irradiated defects and the nuclear transformation elements were detected by electron spin resonance (ESR) and x-ray photoelectron spectroscopy (XPS) method. The exposure of fast neutron and thermal neutron were 1.2x10 20 n/cm 2 and 1.2x10 21 n/cm 2 , respectively. The spreads of ESR spectra of ultra hyperfine structure depending on interaction between 27 Al nuclear spin and electron trapped in tetrahedron consisted of Al atoms was found in the spectra of heavy irradiated AlN. F type defects was estimated 10 19 n/cm 3 . Photoelectrons from 2s and 2p in 28 Si which produced in process of β-decay of 27 Al(n,γ) 28 Al were observed in XPS spectra of irradiated samples. (S.Y.)

  18. Ion irradiation damage in ilmenite under cryogenic conditions

    International Nuclear Information System (INIS)

    Mitchell, J.N.; Yu, N.; Devanathan, R.; Sickafus, K.E.; Nastasi, M.A.

    1996-01-01

    A natural single crystal of ilmenite was irradiated at 100 K with 200 keV Ar 2+ . Rutherford backscattering spectroscopy and ion channeling with 2 MeV He + ions were used to monitor damage accumulation in the surface region of the implanted crystal. At an irradiation fluence of 1 x 10 15 Ar 2+ cm -2 , considerable near-surface He + ion dechanneling was observed, to the extent that ion yield from a portion of the aligned crystal spectrum reached the yield level of a random spectrum. This observation suggests that the near-surface region of the crystal was amorphized by the implantation. Cross-sectional transmission electron microscopy and electron diffraction on this sample confirmed the presence of a 150 mm thick amorphous layer. These results are compared to similar investigations on geikielite (MgTiO 3 ) and spinel (MgAl 2 O 4 ) to explore factors that may influence radiation damage response in oxides

  19. Neutron irradiation damage of a stress relieved TZM alloy

    International Nuclear Information System (INIS)

    Abe, K.; Masuyama, T.; Satou, M.; Hamilton, M.L.

    1992-01-01

    The objective of this work is to study defect microstructures and irradiation hardening in a stress relieved TZM alloy after irradiation in the Fast Flux Test Facility (FFTF) using the Materials Open Test Assembly (MOTA). Disk specimens of the molybdenum alloy TZM that had been stress relieved at 1199 K (929 C) for 0.9 ks (15 min.) were irradiated in the FFTF/MOTA 1F at 679, 793 and 873 K (406, 520, and 600 C) to a fast fluence of ∼9.6 x 10 22 n/cm 2 . Microstructures were observed in a transmission electron microscope (TEM). Dislocation structures consisted of isolated loops, aggregated loops (rafts) and elongated dislocations. The size of the loops increased with the irradiation temperature. Void swelling was about 1 and 2% at 793 and 873 K (520 and 600 C), respectively. A void lattice was developed in the body centered cubic (bcc) structure with a spacing of 26 - 28 nm. The fine grain size (0.5 - 2 μm) was retained following high temperature irradiation, indicating that the stress relief heat treatment may extend the material's resistance to radiation damage up to high fluence levels. Microhardness measurements indicated that irradiation hardening increased with irradiation temperature. The relationship between the microstructure and the observed hardening was determined

  20. Radiation damage to electronic components

    International Nuclear Information System (INIS)

    Battisti, S.; Bossart, R.; Schoenbacher, H.; Van de Voorde, M.

    1975-01-01

    Characteristic properties are presented of some 40 different electronic components (resistors, capacitors, diodes, transistors, and integrated circuits) which were irradiated in a nuclear reactor up to 1015 n/cm 2 (E > 1 MeV). Complete circuits (e.g. RF amplifiers and detectors, mixers, differential amplifiers, voltage-to-frequency converters, oscillators, power supplies) were irradiated near the CERN Intersecting Storage Rings up to 106 rad(RPL) (dose measured with radiophotoluminescent dosimeters) under simulated operational conditions. Representative measured parameters, such as resistance, capacitance, forward voltage, reverse current, toggle frequencies, are given in graphs as a function of radiation dose. The results are discussed in detail and lead to the over-all conclusion that the operation of electronic components and circuits is seriously affected by radiation environments with doses in the order of 10 13 n/cm 2 or 10 4 rad(RPL); some components and circuits fail completely at doses of 10 14 n/cm 2 or 10 5 rad(RPL). (Author)

  1. Damage induced in semiconductors by swift heavy ion irradiation

    International Nuclear Information System (INIS)

    Levalois, M.; Marie, P.

    1999-01-01

    The behaviour of semiconductors under swift heavy ion irradiation is different from that of metals or insulators: no spectacular effect induced by the inelastic energy loss has been reported in these materials. We present here a review of irradiation effects in the usual semiconductors (silicon, germanium and gallium arsenide). The damage is investigated by means of electrical measurements. The usual mechanisms of point defect creation can account for the experimental results. Besides, some results obtained on the wide gap semiconductor silicon carbide are reported. Concerning the irradiation effects induced by heavy ions in particle detectors, based on silicon substrate, we show that the deterioration of the detector performances can be explained from the knowledge of the substrate properties which are strongly perturbed after high doses of irradiation. Finally, some future ways of investigation are proposed. The silicon substrate is a good example to compare the irradiation effects with different particles such as electrons, neutrons and heavy ions. It is then necessary to use parameters which account for the local energy deposition, in order to describe the damage in the material

  2. Radiation damage in heavy irradiated aluminum nitride

    Energy Technology Data Exchange (ETDEWEB)

    Atobe, Kozo; Honda, Makoto; Fukuoka, Noboru [Naruto Univ. of education, Tokushima (Japan); Okada, Moritami; Nakagawa, Masuo

    1996-04-01

    AlN, one of candidate for ceramic materials used in nuclear fusion reactor, was irradiated by fast and thermal neutrons. The high concentration of irradiated defects and the nuclear transformation elements were detected by electron spin resonance (ESR) and x-ray photoelectron spectroscopy (XPS) method. The exposure of fast neutron and thermal neutron were 1.2x10{sup 20}n/cm{sup 2} and 1.2x10{sup 21}n/cm{sup 2}, respectively. The spreads of ESR spectra of ultra hyperfine structure depending on interaction between {sup 27}Al nuclear spin and electron trapped in tetrahedron consisted of Al atoms was found in the spectra of heavy irradiated AlN. F type defects was estimated 10{sup 19}n/cm{sup 3}. Photoelectrons from 2s and 2p in {sup 28}Si which produced in process of {beta}-decay of {sup 27}Al(n,{gamma}){sup 28}Al were observed in XPS spectra of irradiated samples. (S.Y.)

  3. Apparatus for irradiation with electron beam

    International Nuclear Information System (INIS)

    Uehara, K.; Ito, A.; Nishimune, K.; Fujita, K.

    1976-01-01

    An irradiation apparatus with high energy electrons is disclosed in which a wire shaped or linear object to be irradiated is moved back and forth many times under an electron window so as to irradiate it with an electron beam. According to one feature of the invention, an electron beam, which leaks through gaps between the objects to be irradiated or which penetrates the objects to be irradiated, is reversed by a magnetic field approximately perpendicular to the scanning face of the electron beam by means of a magnet which is disposed under the objects to be irradiated, and the reversed electron beam is thereby again applied to the objects to be irradiated. A high utilization rate of the electron beam is accomplished, and the objects can be thereby uniformly irradiated with the electron beam. 4 claims, 6 drawing figures

  4. Relative effectiveness of electron-proton damage on organic coatings

    International Nuclear Information System (INIS)

    Bartolomei, P.; Cabrini, A.

    1988-01-01

    With aim to verify the validity of simulation with photon irradiators, of damage caused on internal containment coatings by beta plus gamma mixed field following to a LOCA in LWR, irradiation tests with Co 60 photon and with nearly 1.5 MeV mean energy electrons have been performed. Changes of some properties of coating film have been verified versus absorbed doses up to 1000 KGy (100 Mrad). A special technique for measurement of dose absorbed in thin film of coating has been tested, to be related to absorbed dose in organic dosimeters and in water (Fricke solution) dosimeter. The changes of considered properties (tensile strength, ease to decontamination, color, brightness) do not allow at the moment, to determine undoubtedly the degree of equivalence between radiation damage to coatings by two types of radiation. A strong backscatter effect mainly evident in electron irradiation, has been pointed out, which contribute to damage to coating film

  5. Damage studies on tungsten due to helium ion irradiation

    International Nuclear Information System (INIS)

    Dutta, N.J.; Buzarbaruah, N.; Mohanty, S.R.

    2014-01-01

    Highlights: • Used plasma focus helium ion source to study radiation induced damage on tungsten. • Surface analyses confirm formation of micro-crack, bubbles, blisters, pinholes, etc. • XRD patterns confirm development of compressive stress due to thermal load. • Reduction in hardness value is observed in the case of exposed sample. - Abstract: Energetic and high fluence helium ions emitted in a plasma focus device have been used successfully to study the radiation induced damage on tungsten. The reference and irradiated samples were characterized by optical microscopy, field emission scanning electron microscopy, X-ray diffraction and by hardness testers. The micrographs of the irradiated samples at lower magnification show uniform mesh of cracks of micrometer width. However at higher magnification, various types of crystalline defects such as voids, pinholes, bubbles, blisters and microcracks are distinctly noticed. The prominent peaks in X-ray diffraction spectrum of irradiated samples are seen shifted toward higher Bragg angles, thus indicating accumulation of compressive stress due to the heat load delivered by helium ions. A marginal reduction in hardness of the irradiated sample is also noticed

  6. Electron accelerator technology research in food irradiation

    International Nuclear Information System (INIS)

    Jin Jianqiao; Ye Mingyang; Zhang Yue; Yang Bin; Xu Tao; Kong Xiangshan

    2014-01-01

    Electronic accelerator was applied to instead of cobalt sources for food irradiation, to keep food quality and to improve the effect of the treatment. Appropriate accelerator parameters lead to optimal technique. The irradiation effect is associated with the relationship between uniformity and irradiating speed, the effect of cargo size on radiation penetration, as well as other factors that affect the irradiation effects. Industrialization of electron accelerator irradiation will be looked to the future. (authors)

  7. Radiation damage in nonmetallic solids under dense electronic excitation

    International Nuclear Information System (INIS)

    Itoh, Noriaki; Tanimura, Katsumi; Nakai, Yasuo

    1992-01-01

    Basic processes of radiation damage of insulators by dense electronic excitation are reviewed. First it is pointed out that electronic excitation of nonmetallic solids produces the self-trapped excitons and defect-related metastable states having relatively long lifetimes, and that the excitation of these metastable states, produces stable defects. The effects of irradiation with heavy ions, including track registration, are surveyed on the basis of the microscopic studies. It is pointed out also that the excitation of the metastable states plays a role in laser-induced damage at relatively low fluences, while the laser damage has been reported to be governed by heating of free electrons produced by multiphoton excitation. Difference in the contributions of the excitation of metastable defects to laser-induced damage of surfaces, or laser ablation, and laser-induced bulk damage is stressed. (orig.)

  8. Electron irradiation-induced destruction of carbon nanotubes in electron microscopes

    International Nuclear Information System (INIS)

    Molhave, Kristian; Gudnason, Sven Bjarke; Pedersen, Anders Tegtmeier; Clausen, Casper Hyttel; Horsewell, Andy; Boggild, Peter

    2007-01-01

    Observations of carbon nanotubes under exposure to electron beam irradiation in standard transmission electron microscope (TEM) and scanning electron microscope (SEM) systems show that such treatment in some cases can cause severe damage of the nanotube structure, even at electron energies far below the approximate 100 keV threshold for knock-on damage displacing carbon atoms in the graphene structure. We find that the damage we observe in one TEM can be avoided by use of a cold finger. This and the morphology of the damage imply that water vapour, which is present as a background gas in many vacuum chambers, can damage the nanotube structure through electron beam-induced chemical reactions. Though, the dependence on the background gas makes these observations specific for the presently used systems, the results demonstrate the importance of careful assessment of the level of subtle structural damage that the individual electron microscope system can do to nanostructures during standard use

  9. Ion irradiation damage in ilmenite at 100 K

    International Nuclear Information System (INIS)

    Mitchell, J.N.; Yu, N.; Devanathan, R.; Sickafus, K.E.; Nastasi, M.A.

    1997-01-01

    A natural single crystal of ilmenite (FeTiO 3 ) was irradiated at 100 K with 200 keV Ar 2+ . Rutherford backscattering spectroscopy and ion channeling with MeV He + ions were used to monitor damage accumulation in the surface region of the implanted crystal. At an irradiation fluence of 1 x 10 15 Ar 2+ cm -2 , considerable near-surface He + ion dechanneling was observed, to the extent that ion yield from a portion of the aligned crystal spectrum reached the yield level of a random spectrum. This observation suggests that the near-surface region of the crystal was amorphized by the implantation. Cross-sectional transmission electron microscopy and electron diffraction on this sample confirmed the presence of a 150 nm thick amorphous layer. These results are compared to similar investigations on geikielite (MgTiO 3 ) and spinel (MgAl 2 O 4 ) to explore factors that may influence radiation damage response in oxides

  10. Ion irradiation damage in ilmenite at 100 K

    Science.gov (United States)

    Mitchell, J.N.; Yu, N.; Devanathan, R.; Sickafus, K.E.; Nastasi, M.A.; Nord, G.L.

    1997-01-01

    A natural single crystal of ilmenite (FeTiO3) was irradiated at 100 K with 200 keV Ar2+. Rutherford backscattering spectroscopy and ion channeling with 2 MeV He+ ions were used to monitor damage accumulation in the surface region of the implanted crystal. At an irradiation fluence of 1 ?? 1015 Ar2+/cm2, considerable near-surface He+ ion dechanneling was observed, to the extent that ion yield from a portion of the aligned crystal spectrum reached the yield level of a random spectrum. This observation suggests that the near-surface region of the crystal was amorphized by the implantation. Cross-sectional transmission electron microscopy and electron diffraction on this sample confirmed the presence of a 150 nm thick amorphous layer. These results are compared to similar investigations on geikielite (MgTiO3) and spinel (MgAl2O4) to explore factors that may influence radiation damage response in oxides.

  11. Irradiation damage in U{sub 3}Si

    Energy Technology Data Exchange (ETDEWEB)

    MacEwan, J R; Bethune, B

    1969-04-15

    The ordered body-centered tetragonal structure of U{sub 3}S1 transforms allotropically or by irradiation damage to ordered and disordered face -centered cubic structures respectively. An exposure of about 6 x 10{sup 16} fissions/cm{sup 3} at 100{sup o}C produced X-ray diffraction patterns of the cubic form with a 0.6% decrease in X-ray density. However, immersion density measurements showed a volume increase of 2.3% at a similar exposure. Further irradiation removed all but two peaks from the diffraction pattern indicating a trend to an amorphous structure. Electrical resistivity measurements showed that U{sub 3}Si is an electronic conductor with a large positive temperature coefficient. Measurements made below the irradiation temperature of 100{sup o}C showed that the temperature coefficient decreased with irradiation and approached zero at high exposure, Amorphous materials have a negligible temperature coefficient, so the result confirms the trend observed by X-ray analyses. (author)

  12. Study of irradiation damage structures in austenitic stainless steels

    International Nuclear Information System (INIS)

    Hamada, Shozo

    1997-08-01

    The irradiation damage microstructures in austenitic stainless steels, which have been proposed to be a candidate of structural materials of a fusion reactor, under ions and neutrons irradiation have been studied. In ion irradiation experiments, cross-sectional observation of the depth distribution of damage formed due to ion irradiation became available. Comparison and discussion between experimental results with TEM and the calculated ones in the depth profiles of irradiation damage microstructures. Further, dual-phase stainless steels, consisted of ferritic/austenitic phases, showed irradiation-induced/enhanced precipitation during ion irradiation. High Flux Isotope Reactor with high neutron fluxes was employed in neutron-irradiation experiments. Swelling of 316 steel showed irradiation temperature dependence and this had strong correlation with phase instability under heavy damage level. Swelling resistance of Ti-modified austenitic stainless steel, which has good swelling resistance, decreased during high damage level. This might be caused by the instability of Ti-carbide particles. The preparation method to reduce higher radioactivity of neutron-irradiated TEM specimen was developed. (author). 176 refs

  13. Study of irradiation damage structures in austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, Shozo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-08-01

    The irradiation damage microstructures in austenitic stainless steels, which have been proposed to be a candidate of structural materials of a fusion reactor, under ions and neutrons irradiation have been studied. In ion irradiation experiments, cross-sectional observation of the depth distribution of damage formed due to ion irradiation became available. Comparison and discussion between experimental results with TEM and the calculated ones in the depth profiles of irradiation damage microstructures. Further, dual-phase stainless steels, consisted of ferritic/austenitic phases, showed irradiation-induced/enhanced precipitation during ion irradiation. High Flux Isotope Reactor with high neutron fluxes was employed in neutron-irradiation experiments. Swelling of 316 steel showed irradiation temperature dependence and this had strong correlation with phase instability under heavy damage level. Swelling resistance of Ti-modified austenitic stainless steel, which has good swelling resistance, decreased during high damage level. This might be caused by the instability of Ti-carbide particles. The preparation method to reduce higher radioactivity of neutron-irradiated TEM specimen was developed. (author). 176 refs.

  14. (100) faceted anion voids in electron irradiated fluorite

    International Nuclear Information System (INIS)

    Johnson, E.

    1979-01-01

    High fluence electron irradiation of fluorite crystals in the temperature range 150 to 320 K results in formation of a simple cubic anion void superlattice. Above 320 K the damage structure changes to a random distribution of large [001] faceted anion voids. This voidage behaviour, similar to that observed in a range of irradiated metals, is discussed in terms points defect rather than conventional colour centre terminology. (Auth.)

  15. Elemental process of amorphization induced by electron irradiation in Si

    International Nuclear Information System (INIS)

    Yamasaki, Jun; Takeda, Seiji; Tsuda, Kenji

    2002-01-01

    We recently found that amorphization is induced in Si by electron irradiation. Examining the amorphization systematically, we have established the diagram of steady states under electron irradiation, either amorphous Si (a-Si) or crystalline Si (c-Si) as a function of incident electron energy, electron dose, and irradiation temperature. Utilizing transmission electron microscopy, electron energy filtered diffraction and electron energy-loss spectroscopy, we have characterized the atomic structure, the electronic structure, and the thermal stability of a-Si induced by electron irradiation. Based on the experimental data, we have also concluded that the amorphization is caused by the accumulation of not point defects but small cascade damages. Analyzing the change in the intensity of halo diffraction rings during amorphization, we have clarified that the smallest cascade damage that contributes to amorphization includes only about four Si atoms. This presumably supports the amorphization mechanism that four self-interstitial atoms form the quasistable structure I4 in c-Si and it becomes an amorphous embryo

  16. Microstructure and damage behavior of W-Cr alloy under He irradiation

    Science.gov (United States)

    Huang, Ke; Luo, Lai-Ma; Zan, Xiang; Xu, Qiu; Liu, Dong-Guang; Zhu, Xiao-Yong; Cheng, Ji-Gui; Wu, Yu-Cheng

    2018-04-01

    In this study, a large-power inductively coupled plasma source was designed to perform the continuous helium ion irradiations of W-Cr binary alloy (W-20 wt%Cr) under relevant conditions of the International Thermonuclear Experimental Reactor. Surface damages and microstructures of irradiated W-20Cr were observed by using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. The addition of Cr dramatically enhanced the micro-hardness of the obtained bulk materials, and the interface between the W matrix and the second phase Cr-O is a semi-coherent interface. After irradiation, the doping of Cr element effectively reduces the damage of the W matrix during the irradiation process. The semi-coherent interface between the second phase and the W matrix improves the anti-irradiation performance of the W-20Cr alloy.

  17. Assessment of electron beam-induced abnormal development and DNA damage in Spodoptera litura (F.) (Lepidoptera: Noctuidae)

    International Nuclear Information System (INIS)

    Yun, Seung- Hwan; Lee, Seon-Woo; Koo, Hyun-Na; Kim, Gil- Hah

    2014-01-01

    The armyworm, Spodoptera litura (F.) is a polyphagous and important agricultural pest worldwide. In this study, we examined the effect of electron beam irradiation on developmental stages, reproduction, and DNA damage of S. litura. Eggs (0–24 h old), larvae (3rd instar), pupae (3 days old after pupation), and adults (24 h after emergence) were irradiated with electron beam irradiation of six levels between 30 and 250 Gy. When eggs were irradiated with 100 Gy, egg hatching was completely inhibited. When the larvae were irradiated, the larval period was significantly delayed, depending on the doses applied. At 150 Gy, the fecundity of adults that developed from irradiated pupae was entirely inhibited. However, electron beam irradiation did not induce the instantaneous death of S. litura adults. Reciprocal crosses between irradiated and unirradiated moths demonstrated that females were more radiosensitive than males. We also conducted the comet assay immediately after irradiation and over the following 5 days period. Severe DNA fragmentation in S. litura cells was observed just after irradiation and the damage was repaired during the post-irradiation period in a time-dependent manner. However, at more than 100 Gy, DNA damage was not fully recovered. - Highlights: • Electron beam irradiation induced abnormal development of the cutworm. • Electron beam irradiation induced the sterility of the cutworm. • Electron beam irradiation increased levels of DNA damage. • DNA damage by high irradiation exposure was not completely repaired

  18. Radiation damage of pixelated photon detector by neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Isamu [KEK, 1-1 Oho Tsukuba 305-0801 (Japan)], E-mail: isamu.nakamura@kek.jp

    2009-10-21

    Radiation Damage of Pixelated Photon Detector by neutron irradiation is reported. MPPC, one of PPD or Geiger-mode APD, developed by Hamamatsu Photonics, is planned to be used in many high energy physics experiments. In such experiments radiation damage is a serious issue. A series of neutron irradiation tests is performed at the Reactor YAYOI of the University of Tokyo. MPPCs were irradiated at the reactor up to 10{sup 12}neutron/cm{sup 2}. In this paper, the effect of neutron irradiation on the basic characteristics of PPD including gain, noise rate, photon detection efficiency is presented.

  19. Dose distributions in electron irradiated plastic tubing

    International Nuclear Information System (INIS)

    Miller, A.; Pederson, W.B.

    1981-01-01

    Plastic tubes have been crosslinked by irradiation at a 10 MeV linear electron accelerator and at a 400 keV DC electron accelerator at different irradiation geometries. The diameter of the different tubes was 20, 33 and 110 millimeters. Dose distributions have been measured with thin radiochromic dye films, indicating that in all cases irradiation from two sides is a necessary and sufficient condition for obtaining a satisfactory dose distribution. (author)

  20. Pharmacology of post-irradiation damage of blood capillaries

    International Nuclear Information System (INIS)

    Pospisil, J.; Pouckova, P.

    1979-01-01

    Available literature data are summed up on the effect of a number of substances on irradiation damage to blood capillaries. The substances include vitamins, bioflavonoids, serotonine, histamine, bradykinin, ACTH, adrenal hormones, vasopressin, estrogens, prostaglandins, escin 1-butanol, diisopropylfluorophosphate, phenoxybenzamine, 1,4-dihydroxybenzenesulphonic acid derivatives, and xi-aminohexanoic acid. The data include the effects of the substances administered before and after irradiation on blood capillary damage and on mortality. (Ha)

  1. Effects of electron beam irradiation on inorganic exchanger AMP

    International Nuclear Information System (INIS)

    Rao, K.L.N.; Mathew, C.; Deshpande, R.S.; Jadhav, A.V.; Pande, B.M.; Shukla, J.P.

    1996-01-01

    The heteropolyacid salt inorganic exchanger ammonium molybdophosphate (AMP) was subjected to an electron dose upto 2 MGy to assess any possible radiation damage. The breakthrough and total exchange capacity of AMP for Cs + from simulated fission product solutions were determined for both control and irradiated samples. The scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX) were deployed to examine any marked microscopic changes taking place in this exchanger. (author). 3 refs., 3 figs

  2. Un-repairable DNA damage in cell due to irradiation

    International Nuclear Information System (INIS)

    Yoshii, Giichi

    1992-01-01

    Radiation-induced cell reproductive deactivation is caused by damage to DNA. In a cell, cellular DNA radical reacts with diffusion controlled rate and generates DNA peroxide radical. The chemical repair of DNA radical with hydrogen donation by thiol competes with the reaction of oxygen with same radicals in the DNA molecules. From the point reaction rates, the prolongation of radical life time is not as great as expected from the reduction in the glutathione content of the cell. This indicates that further reducting compounds (protein bound thiol) are present in the cell. The residual radicals are altered to strand breaks, base damages and so on. The effective lesions for a number of endpoints is un-repaired double strand break, which has been discovered in a cluster. This event gives risk to high LET radiation or to a track end of X-rays. For X- or electron irradiations the strand breaks are frequently induced by the interactions between sublesions on two strands in DNA. A single strand break followed by radical action may be unstable excited state, because of remaining sugar radical action and of having negative charged phosphates, in which strands breaks will be rejoined in a short time to stable state. On the same time, a break in the double helix will be immediately produced if two breaks are on either or approximately opposite locations. The formation of a double strand break in the helix depends on the ion strength of the cell. The potassium ions are largely released from polyanionic strand during irradiation, which results in the induction of denatured region. Double strand break with the denatured region seems to be un-repairable DNA damage. (author)

  3. Irradiation damage in boron carbide: point defects, clusters and helium bubbles

    International Nuclear Information System (INIS)

    Stoto, T.; Zuppiroli, L.

    1986-06-01

    Boron carbide is a refractory hard and light material of interest in nuclear technology (fission and also fusion). Transmission electron microscopy was used to examine the properties of radiation induced damage. Firstly, the production of point defects and their clustering was studied in samples irradiated by 1 MeV electron in a high voltage electron microscope at selected temperatures from 12 K to 1000 K. Secondly, conventional transmission electron microscopy was used to understand the production of helium bubbles in neutron irradiated boron carbide and their role in the generation of microcracks. Finally, the interaction between point defects and bubbles was also examined

  4. Use of high voltage electron microscope to simulate radiation damage by neutrons

    International Nuclear Information System (INIS)

    Mayer, R.M.

    1976-01-01

    The use of the high voltage electron microscope to simulate radiation damage by neutrons is briefly reviewed. This information is important in explaining how alloying affects void formation during neutron irradiation

  5. Effect of melatonin and time of administration on irradiation-induced damage to rat testes

    Directory of Open Access Journals (Sweden)

    G. Take

    2009-07-01

    Full Text Available The effect of ionizing irradiation on testes and the protective effects of melatonin were investigated by immunohistochemical and electron microscopic methods. Eighty-two adult male Wistar rats were divided into 10 groups. The rats in the irradiated groups were exposed to a sublethal irradiation dose of 8 Gy, either to the total body or abdominopelvic region using a 60Co source at a focus of 80 cm away from the skin in the morning or evening together with vehicle (20% ethanol or melatonin administered 24 h before (10 mg/kg, immediately before (20 mg/kg and 24 h after irradiation (10 mg/kg, all ip. Caspace-3 immunoreactivity was increased in the irradiated group compared to control (P < 0.05. Melatonin-treated groups showed less apoptosis as indicated by a considerable decrease in caspace-3 immunoreactivity (P < 0.05. Electron microscopic examination showed that all spermatogenic cells, especially primary spermatocytes, displayed prominent degeneration in the groups submitted to total body and abdominopelvic irradiation. However, melatonin administration considerably inhibited these degenerative changes, especially in rats who received abdominopelvic irradiation. Total body and abdominopelvic irradiation induced identical apoptosis and testicular damage. Chronobiological assessment revealed that biologic rhythm does not alter the inductive effect of irradiation. These data indicate that melatonin protects against total body and abdominopelvic irradiation. Melatonin was more effective in the evening abdominopelvic irradiation and melatonin-treated group than in the total body irradiation and melatonin-treated group.

  6. Electron damage and defects in organic crystals

    International Nuclear Information System (INIS)

    Howitt, D.G.

    1976-06-01

    The nature of the defects discernable from and the radiation damage that is induced by high resolution electron microscopy is reported. The structural aspects of the radiation damage process can be correlated to the expected radiochemical decomposition of these materials and these effects identified. The types of local defect formed by radiation damage are often clearly distinguishable, in high resolution images, from those inherent in the microstructure. Techniques used in this type of electron microscopy and the limitations imposed by radiation damage are described as are the relevant radiochemical characteristics of these processes. In copper pthalocyanine, microstructural features distinct from those induced by radiation damage were identified which are consistent with those predicted and described by other workers in similar materials. The high resolution studies indicate that some of the microstructures observed are caused by structural rearrangements that can account, to some extent, for additional crystallographic forms that have been identified in this material and the photochemical behaviour of related structures

  7. Green coffee decontamination by electron beam irradiation

    International Nuclear Information System (INIS)

    Nemtanu, Monica R.; Brasoveanu, Mirela; Grecu, Maria Nicoleta; Minea, R.

    2005-01-01

    Microbiological load of green coffee is a real problem considering that it is extremely sensitive to contamination. Irradiation is a decontamination method for a lot of foodstuffs, being a feasible, very effective and environment friendly one. Beans and ground green coffee were irradiated with electron beams up to 40 kGy. Microbial load, rheological behavior, electron paramagnetic resonance (EPR) and visible spectroscopy were carried out. The results show that electron beam irradiation of green coffee could decontaminate it without severe changes in its properties

  8. Structural changes induced by electron irradiation

    International Nuclear Information System (INIS)

    Koike, J.; Pedraza, D.F.

    1993-01-01

    Highly oriented pyrolytic graphite was irradiated at room temperature with 300 kV electrons. Transmission electron microscopy and electron energy loss spectroscopy were employed to study the structural changes produced by irradiation. The occurrence of a continuous ring intensity in the selected area diffraction (SAD) pattern obtained on a specimen irradiated with the electron beam parallel to the c-crystallographic axis indicated that microstructural changes had occurred. However, from the SAD pattern obtained for the specimens tilted relative to the irradiation direction, it was found that up to a fluence of 1.1x10 27 e/m 2 graphite remained crystalline. An SAD pattern of a specimen irradiated with the electron beam perpendicular to the c-axis confirmed the persistence of crystalline order. High resolution electron microscopy showed that ordering along the c-axis direction remained. A density reduction of 8.9% due to irradiation was determined from the plasmon frequency shift. A qualitative model is proposed to explain these observations. A new determination of the threshold displacement energy, Ed, of carbon atoms in graphite was done by examining the appearance of a continuous ring in the SAD pattern at various electron energies. A value of 30 eV was obtained whether the incident electron beam was parallel or perpendicular to the c-axis, demonstrating that Ed is independent of the displacement direction

  9. Leydig cell damage after testicular irradiation for lymphoblastic leukemia

    International Nuclear Information System (INIS)

    Shalet, S.M.; Horner, A.; Ahmed, S.R.; Morris-Jones, P.H.

    1985-01-01

    The effect of testicular irradiation on Leydig cell function has been studied in a group of boys irradiated between 1 and 5 years earlier for a testicular relapse of acute lymphoblastic leukemia. Six of the seven boys irradiated during prepubertal life had an absent testosterone response to HCG stimulation. Two of the four boys irradiated during puberty had an appropriate basal testosterone level, but the testosterone response to HCG stimulation was subnormal in three of the four. Abnormalities in gonadotropin secretion consistent with testicular damage were noted in nine of the 11 boys. Evidence of severe Leydig cell damage was present irrespective of whether the boys were studied within 1 year or between 3 and 5 years after irradiation, suggesting that recovery is unlikely. Androgen replacement therapy has been started in four boys and will be required by the majority of the remainder to undergo normal pubertal development

  10. Neutron and gamma irradiation damage to organic materials.

    Energy Technology Data Exchange (ETDEWEB)

    White, Gregory Von, II; Bernstein, Robert

    2012-04-01

    This document discusses open literature reports which investigate the damage effects of neutron and gamma irradiation on polymers and/or epoxies - damage refers to reduced physical chemical, and electrical properties. Based on the literature, correlations are made for an SNL developed epoxy (Epon 828-1031/DDS) with an expected total fast-neutron fluence of {approx}10{sup 12} n/cm{sup 2} and a {gamma} dosage of {approx}500 Gy received over {approx}30 years at < 200 C. In short, there are no gamma and neutron irradiation concerns for Epon 828-1031/DDS. To enhance the fidelity of our hypotheses, in regards to radiation damage, we propose future work consisting of simultaneous thermal/irradiation (neutron and gamma) experiments that will help elucidate any damage concerns at these specified environmental conditions.

  11. Electron microscopy of boron carbide before and after electron irradiation

    International Nuclear Information System (INIS)

    Stoto, T.; Zuppiroli, L.; Beauvy, M.; Athanassiadis, T.

    1984-06-01

    The microstructure of boron carbide has been studied by electron microscopy and related to the composition of the material. After electron irradiations in an usual transmission electron microscope and in a high voltage electron microscope at different temperatures and fluxes no change of these microstructures have been observed but a sputtering of the surface of the samples, which has been studied quantitatively [fr

  12. Electron spin resonance identification of irradiated fruits

    International Nuclear Information System (INIS)

    Raffi, J.J.; Agnel, J.-P.L.

    1989-01-01

    The electron spin resonance spectrum of achenes, pips, stalks and stones from irradiated fruits (stawberry, raspberry, red currant, bilberry, apple, pear, fig, french prune, kiwi, water-melon and cherry) always displays, just after γ-treatment, a weak triplet (a H ∼30 G) due to a cellulose radical; its left line (lower field) can be used as an identification test of irradiation, at least for strawberries, raspberries, red currants or bilberries irradiated in order to improve their storage time. (author)

  13. Electron beam irradiation effect on GaN HEMT

    International Nuclear Information System (INIS)

    Lou Yinhong; Guo Hongxia; Zhang Keying; Wang Yuanming; Zhang Fengqi

    2011-01-01

    In this work, GaN HEMTs (High Electron Mobility Transistor) were irradiated by 0.8 and 1.2 MeV electron beams, and the irradiation effects were investigated. The results show that the device damage caused by 0.8 MeV electrons is more serious than that by 1.2 MeV electrons. Saturation drain current increase and threshold voltage negative shift are due to trapped positive charge from ionization in the AlGaN layer and N, Ga vacancy from non-ionizing energy loss in the GaN layer. Electron traps and trapped positive charges from non-ionizing in the AlGaN layer act as trap-assisted-tunneling centers that increase the gate leakage current.(authors)

  14. Minimizing material damage using low temperature irradiation

    International Nuclear Information System (INIS)

    Craven, E.; Hasanain, F.; Winters, M.

    2012-01-01

    Scientific advancements in healthcare driven both by technological breakthroughs and an aging and increasingly obese population have lead to a changing medical device market. Complex products and devices are being developed to meet the demands of leading edge medical procedures. Specialized materials in these medical devices, including pharmaceuticals and biologics as well as exotic polymers present a challenge for radiation sterilization as many of these components cannot withstand conventional irradiation methods. The irradiation of materials at dry ice temperatures has emerged as a technique that can be used to decrease the radiation sensitivity of materials. The purpose of this study is to examine the effect of low temperature irradiation on a variety of polymer materials, and over a range of temperatures from 0 °C down to −80 °C. The effectiveness of microbial kill is also investigated under each of these conditions. The results of the study show that the effect of low temperature irradiation is material dependent and can alter the balance between crosslinking and chain scission of the polymer. Low temperatures also increase the dose required to achieve an equivalent microbiological kill, therefore dose setting exercises must be performed under the environmental conditions of use. - Highlights: ► A study is performed to quantify low temperature irradiation effects on polymer materials and BIs. ► Low temperature irradiation alters the balance of cross-linking and chain scissoning in polymers. ► Low temperatures provide radioprotection for BIs. ► Benefits of low temperatures are application specific and must be considered when dose setting.

  15. High energy electron irradiation of flowable materials

    International Nuclear Information System (INIS)

    Offermann, B.P.

    1975-01-01

    In order to efficiently irradiate a flowable material with high energy electrons, a hollow body is disposed in a container for the material and the material is caused to flow in the form of a thin layer across a surface of the body from or to the interior of the container while the material flowing across the body surface is irradiated. (U.S.)

  16. Correlation of simulated TEM images with irradiation induced damage

    International Nuclear Information System (INIS)

    Schaeublin, R.; Almeida, P. de; Almazouzi, A.; Victoria, M.

    2000-01-01

    Crystal damage induced by irradiation is investigated using transmission electron microscopy (TEM) coupled to molecular dynamics (MD) calculations. The displacement cascades are simulated for energies ranging from 10 to 50 keV in Al, Ni and Cu and for times of up to a few tens of picoseconds. Samples are then used to perform simulations of the TEM images that one could observe experimentally. Diffraction contrast is simulated using a method based on the multislice technique. It appears that the cascade induced damage in Al imaged in weak beam exhibits little contrast, which is too low to be experimentally visible, while in Ni and Cu a good contrast is observed. The number of visible clusters is always lower than the actual one. Conversely, high resolution TEM (HRTEM) imaging allows most of the defects contained in the sample to be observed, although experimental difficulties arise due to the low contrast intensity of the smallest defects. Single point defects give rise in HTREM to a contrast that is similar to that of cavities. TEM imaging of the defects is discussed in relation to the actual size of the defects and to the number of clusters deduced from MD simulations

  17. Minimizing material damage using low temperature irradiation

    Science.gov (United States)

    Craven, E.; Hasanain, F.; Winters, M.

    2012-08-01

    Scientific advancements in healthcare driven both by technological breakthroughs and an aging and increasingly obese population have lead to a changing medical device market. Complex products and devices are being developed to meet the demands of leading edge medical procedures. Specialized materials in these medical devices, including pharmaceuticals and biologics as well as exotic polymers present a challenge for radiation sterilization as many of these components cannot withstand conventional irradiation methods. The irradiation of materials at dry ice temperatures has emerged as a technique that can be used to decrease the radiation sensitivity of materials. The purpose of this study is to examine the effect of low temperature irradiation on a variety of polymer materials, and over a range of temperatures from 0 °C down to -80 °C. The effectiveness of microbial kill is also investigated under each of these conditions. The results of the study show that the effect of low temperature irradiation is material dependent and can alter the balance between crosslinking and chain scission of the polymer. Low temperatures also increase the dose required to achieve an equivalent microbiological kill, therefore dose setting exercises must be performed under the environmental conditions of use.

  18. TEM study of damage recovery in SiC by swift Xe ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Skuratov, V.A., E-mail: skuratov@jinr.ru [Joint Institute for Nuclear Research, Dubna (Russian Federation); O’Connell, J. [Centre for HRTEM, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Sohatsky, A.S. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Neethling, J. [Centre for HRTEM, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa)

    2014-05-01

    The microstructure of 4H–SiC samples subsequently irradiated with low energy He (10 keV), Ti (220 keV) and high energy (167 MeV) Xe ions has been studied using cross-sectional transmission electron microscopy. It was found that xenon ions with fluences above 10{sup 13} cm{sup −2} restore crystallinity in a heavily damaged partially amorphous zone. No, or negligible damage recovery is observed in fully amorphized layers of silicon carbide.

  19. TEM study of damage recovery in SiC by swift Xe ion irradiation

    International Nuclear Information System (INIS)

    Skuratov, V.A.; O’Connell, J.; Sohatsky, A.S.; Neethling, J.

    2014-01-01

    The microstructure of 4H–SiC samples subsequently irradiated with low energy He (10 keV), Ti (220 keV) and high energy (167 MeV) Xe ions has been studied using cross-sectional transmission electron microscopy. It was found that xenon ions with fluences above 10 13 cm −2 restore crystallinity in a heavily damaged partially amorphous zone. No, or negligible damage recovery is observed in fully amorphized layers of silicon carbide

  20. Void formation in pure aluminium irradiated with high-energetic electron beams and gamma-quanta

    DEFF Research Database (Denmark)

    Gan, V. V.; Ozhigou, L. S.; Yamnitsky, V. A.

    1983-01-01

    The spatial distribution of displaced atoms and helium atoms and also the spectra of damaging energies of primary displaced atoms in a thick aluminium target irradiated with electrons of 225 MeV energy were calculated. Pure aluminium (99.9999%) irradiated up to 0.04 dose was studied by electron...

  1. Food irradiation by low energy electrons

    International Nuclear Information System (INIS)

    Bird, J.R.

    1985-01-01

    For some special cases, the use of low energy electrons has advantages over the use of gamma-rays or higher energy electrons for the direct irradiation of food. These advantages arise from details of the interaction processes which are responsible for the production of physical, chemical and biological effects. Factors involved include depth of penetration, dose distribution, irradiation geometry, the possible production of radioactivity and costs

  2. Low damage electrical modification of 4H-SiC via ultrafast laser irradiation

    Science.gov (United States)

    Ahn, Minhyung; Cahyadi, Rico; Wendorf, Joseph; Bowen, Willie; Torralva, Ben; Yalisove, Steven; Phillips, Jamie

    2018-04-01

    The electrical properties of 4H-SiC under ultrafast laser irradiation in the low fluence regime (engineering spatially localized structural and electronic modification of wide bandgap materials such as 4H-SiC with relatively low surface damage via low temperature processing.

  3. In-situ observation system for dual ion irradiation damage

    International Nuclear Information System (INIS)

    Furuno, Shigemi; Hojou, Kiichi; Otsu, Hitoshi; Sasaki, T.A.; Izui, Kazuhiko; Tukamoto, Tetsuo; Hata, Takao.

    1992-01-01

    We have developed an in-situ observation and analysis system during dual ion beam irradiation in an electron microscope. This system consists of an analytical electron microscope of JEM-4000FX type equipped with a parallel EELS and an EDS attachments and linked with two sets of ion accelerators of 40 kV. Hydrogen and helium dual-ion beam irradiation experiments were performed for SiC crystals. The result of dual-ion beam irradiation was compared with those of helium and hydrogen single ion irradiations. It is clearly seen that the dual-ion irradiation has the effect of suppressing bubble formation and growth in comparison with the case of single helium ion irradiation. (author)

  4. Comparison of ion irradiation damage in three grades of unalloyed molybdenum

    International Nuclear Information System (INIS)

    Bradley, E.R.

    1976-01-01

    Transmission electron microscopy has been employed to characterize the ion irradiation damage in three grades of unalloyed molybdenum. The materials were irradiated with 5 MeV Ni 2+ ions at temperatures of 900 and 1000 0 C. Major differences exist in both the void and dislocation components of the damage and are attributed to differences in the carbon content of the three materials. A model, whereby carbon atoms segregate to small loops and decrease the bias for self interstitials, is used to qualitatively explain the observed variations in microstructure

  5. Effects of electron irradiation on LDPE/MWCNT composites

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jianqun [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Li, Xingji, E-mail: lxj0218@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Liu, Chaoming; Rui, Erming [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Liqin [School of Mechatronics, Harbin Institute of Technology, Harbin 150001 (China)

    2015-12-15

    In this study, mutiwalled carbon nanotubes (MWCNTs) were incorporated into low density polyethylene (LDPE) in different concentrations (2%, 4% and 8%) using a melt blending process. Structural, thermal stability and tensile property of the unirradiated/irradiated LDPE/MWCNT composites by 110 keV electrons were investigated by means of scanning electron microscopy (SEM), small angle X-ray scattering (SAXS), Raman spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, thermogravimetric analysis (TGA) and uniaxial tensile techniques. Experimental results show that the addition of MWCNTs obviously increases the ultimate tensile strength of LDPE and decreases the elongation at break, which is attributed to the homogeneous distribution of the MWCNTs in LDPE and intense interaction between MWCNTs and LDPE matrix. Also, the electron irradiation further increases the ultimate tensile strength of LDPE/MWCNT composites, which can be ascribed to the more intense interaction between MWCNTs and LDPE matrix, and the formation of crosslinking sites in LDPE matrix induced by the electron irradiation. The addition of MWCNTs significantly enhances thermal stability of the LDPE due to the hindering effect and the scavenging free radicals, while the electron irradiation decreases thermal stability of the LDPE/MWCNT composites since the structure of the MWCNTs and LDPE matrix damages.

  6. Role of charged particle irradiations in the study of radiation damage correlation

    International Nuclear Information System (INIS)

    Ishino, S.; Sekimura, N.

    1990-01-01

    Charged particle irradiations were originally expected to provide means to simulate the effect of neutron irradiations. However, it has been recognized that quantitative and sometimes even qualitative simulation of neutron radiation damage is difficult and the role of the charged particle irradiations has shifted to establishing fission-fusion correlation based on fundamental understanding of the radiation damage phenomena. The authors have been studying radiation effects in fusion materials using energetic ions from the latter standpoint. In this paper, the authors review recent results using a heavy-ion/electron microscope link facility together with sets of small heavy ion and light ion accelerators on cascade damage produced by energetic primary recoils and on the effect of helium on microstructural and microchemical evolution. Some of the other applications of the ion accelerators will also be mentioned. (orig.)

  7. Mono and sequential ion irradiation induced damage formation and damage recovery in oxide glasses: Stopping power dependence of the mechanical properties

    International Nuclear Information System (INIS)

    Mir, A.H.; Monnet, I.; Toulemonde, M.; Bouffard, S.; Jegou, C.; Peuget, S.

    2016-01-01

    Simple and complex borosilicate glasses were irradiated with single and double ion beams of light and heavy ions over a broad fluence and stopping power range. As a result of the heavy ion irradiation (U, Kr, Au), the hardness was observed to diminish and saturate after a decrease by 35 ± 1%. Unlike slow and swift heavy ion irradiation, irradiation with light ions (He,O) induced a saturation hardness decrease of 18 ± 1% only. During double ion beam irradiation; where glasses were first irradiated with a heavy ion (gold) and then by a light ion (helium), the light ion irradiation induced partial damage recovery. As a consequence of the recovery effect, the hardness of the pre-irradiated glasses increased by 10–15% depending on the chemical composition. These results highlight that the nuclear energy loss and high electronic energy loss (≥4 keV/nm) result in significant and similar modifications whereas light ions with low electronic energy loss (≤1 keV/nm) result in only mild damage formation in virgin glasses and recovery in highly pre-damaged glasses. These results are important to understand the damage formation and recovery in actinide bearing minerals and in glasses subjected to self-irradiation by alpha decays. - Highlights: • Behavior of glasses strongly depends on the electronic energy loss (Se) of the ions. • High Se (≥4 keV/nm) induces large changes in comparison to lower Se values. • Apart from mild damage formation, low Se causes recovery of pre-existing damage. • Alpha induced partial recovery of the damage would occur in nuclear waste glasses.

  8. Possible genetic damage from diagnostic x irradiation. A review

    International Nuclear Information System (INIS)

    Withrow, T.J.; Andersen, F.A.; Yao, K.T.S.; Stratmeyer, M.E.

    1980-08-01

    Although it is known that x irradiation is capable of producing mutations and chromosomal abnormalities in experimental systems, there is little or no direct evidence of such phenomena in humans. This report reviews some human genetic diseases and chromosomal abnormalities as well as the evidence for x-ray induced mutations and chromosomal abnormalities in experimental systems. The examination of these areas reveals that spontaneous chromosomal abnormalities and genetic diseases are associated with the same type of DNA damage that x irradiation produces in experimental systems. Therefore, it is concluded that genetic radiation damage in humans may mainfest itself as an increase in the spontaneous genetic diseases rather than as any unique disease

  9. Functional and morphologic damage in the neonatally irradiated canine kidney

    International Nuclear Information System (INIS)

    Peneyra, R.S.; Jaenke, R.S.

    1985-01-01

    Perinatal irradiation of the developing kidney results in progressive glomerulosclerosis (PGS) and renal failure. This syndrome may result from direct radiation damage to mature deep cortical nephrons and/or nephron functional adaptations resulting from outer cortical nephron ablation. Beagle dogs received single, whole-body exposures (330 R) to 60 Co gamma radiation at 4 days of age (IR4) to study the combined effects of direct radiation damage and nephron loss, or at 30 days of age (IR30) to study the effects of renal irradiation alone. To study the effects of nephron loss alone, dogs underwent unilateral nephrectomy (UN4) or superficial hyperthermic renal ablation (HY4) at 4 days of age. Nephron loss due to irradiation (IR4) and partial renal ablation (UN4 and HY4) was associated with compensatory nephron hypertrophy and increased single nephron glomerular filtration rate (SNGFR), while irradiation at 30 days resulted in transitory decreased SNGFR. Similar degrees of PGS occurred in IR4 dogs which experienced both irradiation and loss of nephrons and UN4 and HY4 dogs which experienced only loss of nephrons. PGS of lesser severity also occurred in IR30 dogs. These findings indicate that PGS associated with perinatal renal irradiation results from direct radiation damage to deep cortical nephrons and compensatory functional changes occurring in response to loss of renal mass

  10. Calculations on neutron irradiation damage in reactor materials

    International Nuclear Information System (INIS)

    Sone, Kazuho; Shiraishi, Kensuke

    1976-01-01

    Neutron irradiation damage calculations were made for Mo, Nb, V, Fe, Ni and Cr. Firstly, damage functions were calculated as a function of neutron energy with neutron cross sections of elastic and inelastic scatterings, and (n,2n) and (n,γ) reactions filed in ENDF/B-III. Secondly, displacement damage expressed in displacements per atom (DPA) was estimated for neutron environments such as fission spectrum, thermal neutron reactor (JMTR), fast breeder reactor (MONJU) and two fusion reactors (The Conceptual Design of Fusion Reactor in JAERI and ORNL-Benchmark). then, damage cross section in units of dpa. barn was defined as a factor to convert a given neutron fluence to the DPA value, and was calculated for the materials in the above neutron environments. Finally, production rates of helium and hydrogen atoms were calculated with (n,α) and (n,p) cross sections in ENDF/B-III for the materials irradiated in the above reactors. (auth.)

  11. Radiation safety of gamma and electron irradiation facilities

    International Nuclear Information System (INIS)

    1992-01-01

    There are currently some 160 gamma irradiation facilities and over 600 electron beam facilities in operation throughout virtually all Member States of the IAEA. The most widespread uses of these facilities are for the sterilization of medical and pharmaceutical products, the preservation of foodstuffs, polymer synthesis and modification, and the eradication of insect infestation. The safety record of this industry has been very good. Nevertheless, there is a potential for accidents with serious consequences. Gamma and electron beam facilities produce very high dose rates during irradiation, so that a person accidentally present in the irradiation chamber can receive a lethal dose within minutes or seconds. Precautions against uncontrolled entry must therefore be taken. Furthermore, gamma irradiation facilities contain large amounts of radioactivity and if the mechanism for retracting the source is damaged, the source may remain exposed, inhibiting direct access to carry out remedial work. Contamination can result from corroded or damaged sources, and decontamination can be very expensive. These aspects clearly indicate the need to achieve a high degree of safety and reliability in the facilities. This can be accomplished by effective quality control together with careful design, manufacture, installation, operation and decommissioning. The guidance in this Safety Series publication is intended for competent authorities responsible for regulating the use of radiation sources as well as the manufacturers, suppliers, installers and users of gamma and electron beam facilities. 20 refs, 6 figs

  12. Interferon synthesis in mouse peritoneal cells damaged by x irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Szolgay, E; T' alas, M

    1976-01-01

    NDV-induced interferon of peritoneal cells of irradiated (x-rays, 400 R) and control mice was investigated in vitro. Irradiation or treatment with hydroxyurea (10(-5) M) and mitomycin C (25 microng/ml) did not change interferon synthesis in spite of an 80 to 90% inhibition of 3H-thymidine incorporation. Increased doses of mitomycin C and treatment with actinomycin D and puromycin blocked interferon production. De novo interferon synthesis occurred in cells with damaged replicative activity of DNA caused by irradiation or by treatment with antimetabolites.

  13. Apparatus for electron beam irradiation of objects

    International Nuclear Information System (INIS)

    Dmitriev, S.P.; Ivanov, A.S.; Sviniin, M.P.; Fedotov, M.T.

    1984-01-01

    This patent provides an apparatus for electron beam irradiation of objects, comprising a shaper of a ribbon-shaped electron beam and a deflecting electromagnet having a frame-type magnetic circuit and used to direct said electron beam onto an irradiated object substantially at an angle of 90 degrees. The deflecting electromagnet has two poles extended over the width of the irradiated object and comprises two windings embracing said poles and connected to a d.c. source. The deflecting electromagnet is arranged in such a manner that the trajectories of the electrons at an area from the shaper to the electromagnet are inclined to the plane of the frame of its magnetic circuit

  14. Void swelling behaviour of austenitic stainless steel during electron irradiation

    International Nuclear Information System (INIS)

    Sheng Zhongqi; Xiao Hong; Peng Feng; Ti Zhongxin

    1994-04-01

    The irradiation swelling behaviour of 00Cr17Ni14Mo2 austenitic stainless steel (AISI 316L) was investigated by means of high voltage electron microscope. Results showed that in solution annealed condition almost no swelling incubation period existed, and the swelling shifted from the transition period to the steady-state one when the displacement damage was around 40 dpa. In cold rolled condition there was evidently incubation period, and when the displacement damage was up to 84 dpa the swelling still remained in the transition period. The average size and density of voids in both conditions were measured, and the factors, which influenced the void swelling, were discussed. (3 figs.)

  15. Electron irradiation of dry food products

    International Nuclear Information System (INIS)

    Gruenewald, Th.

    1983-01-01

    The interest of the industrial food producer is increasing in having the irradiation facility installed in the food processing chain. The throughput of the irradiator should be high and the residence time of the product in the facility should be short. These conditions can be accomplished by electron irradiators. To clarify the irradiation conditions spices taken out of the industrial process, food grade salt, sugar, and gums as models of dry food products were irradiated. With a radiation dose of 10 kGy microbial load can be reduced on 10**4 microorganisms/g. The sensory properties of the spices were not changed in an atypical way. For food grade salt and sugar changes of colour were observed which are due to lattice defects or initiated browning. The irradiation of several gums led only in some cases to an improvement of the thickness properties in the application below 50 deg C, in most cases the thickness effect was reduced. The products were packaged before irradiation. But it would be possible also to irradiate the products without packaging moving the product through the irradiation field in a closed conveyor system. (author)

  16. Electron irradiation of dry food products

    Energy Technology Data Exchange (ETDEWEB)

    Gruenewald, Th [Bundesbahn-Zentralamt, Minden (Germany, F.R.)

    1983-01-01

    The interest of the industrial food producer is increasing in having the irradiation facility installed in the food processing chain. The throughput of the irradiator should be high and the residence time of the product in the facility should be short. These conditions can be accomplished by electron irradiators. To clarify the irradiation conditions spices taken out of the industrial process, food grade salt, sugar, and gums as models of dry food products were irradiated. With a radiation dose of 10 kGy microbial load can be reduced on 10**4 microorganisms/g. The sensory properties of the spices were not changed in an atypical way. For food grade salt and sugar changes of colour were observed which are due to lattice defects or initiated browning. The irradiation of several gums led only in some cases to an improvement of the thickness properties in the application below 50 deg C, in most cases the thickness effect was reduced. The products were packaged before irradiation. But it would be possible also to irradiate the products without packaging moving the product through the irradiation field in a closed conveyor system.

  17. Damage and repair of irradiated mammalian brain

    International Nuclear Information System (INIS)

    Frankel, K.; Lo, E.; Phillips, M.; Fabrikant, J.; Brennan, K.; Valk, P.; Poljak, A.; Delapaz, R.; Woodruff, K.

    1989-07-01

    We have demonstrated that focal charged particle irradiation of the rabbit brain can create well-defined lesions which are observable by nuclear magnetic resonance imaging (NMR) and positron emission tomography (PET) imaging techniques. These are similar, in terms of location and characteristic NMR and PET features, to those that occur in the brain of about 10% of clinical research human subjects, who have been treated for intracranial vascular malformations with stereotactic radiosurgery. These lesions have been described radiologically as ''vasogenic edema of the deep white matter,'' and the injury is of variable intensity and temporal duration, can recede or progress to serious neurologic sequelae, and persist for a considerable period of time, frequently 18 mon to 3 yr. 8 refs., 6 figs

  18. Damage and repair of irradiated mammalian brain

    Energy Technology Data Exchange (ETDEWEB)

    Frankel, K.; Lo, E.; Phillips, M.; Fabrikant, J.; Brennan, K.; Valk, P.; Poljak, A.; Delapaz, R.; Woodruff, K. (Lawrence Berkeley Lab., CA (USA); Stanford Univ., CA (USA). Medical Center; Brookside Hospital, San Pablo, CA (USA))

    1989-07-01

    We have demonstrated that focal charged particle irradiation of the rabbit brain can create well-defined lesions which are observable by nuclear magnetic resonance imaging (NMR) and positron emission tomography (PET) imaging techniques. These are similar, in terms of location and characteristic NMR and PET features, to those that occur in the brain of about 10% of clinical research human subjects, who have been treated for intracranial vascular malformations with stereotactic radiosurgery. These lesions have been described radiologically as vasogenic edema of the deep white matter,'' and the injury is of variable intensity and temporal duration, can recede or progress to serious neurologic sequelae, and persist for a considerable period of time, frequently 18 mon to 3 yr. 8 refs., 6 figs.

  19. Ion Irradiation Damage in Zirconate and Titanate Ceramics for Pu Disposition

    International Nuclear Information System (INIS)

    Stewart, Martin W.; Begg, Bruce D.; Finnie, K.; Colella, Michael; Li, H.; McLeod, Terry; Smith, Katherine L.; Zhang, Zhaoming; Weber, William J.; Thevuthasan, Suntharampillai

    2004-01-01

    In this paper, we discuss the effect of ion irradiation on pyrochlore-rich titanate and defect-fluorite zirconate ceramics designed for plutonium immobilization. Samples, with Ce as an analogue for Pu, were made via oxide routes and consolidated by cold-pressing and sintering. Ion irradiation damage was carried out with 2 MeV Au2+ ions to a fluence of 5 ions nm-2 in the accelerator facilities within the Environmental Molecular Sciences Laboratory at Pacific Northwest National Laboratory. Irradiated and non-irradiated samples were examined by x-ray diffraction, scanning and transmission electron microscopy, x-ray photoelectron and infrared spectroscopy, and spectroscopic ellipsometry. Samples underwent accelerated leach testing at pH 1.75 (nitric acid) at 90 C for 28 days. The zirconate samples were more ion-irradiation damage resistant than the titanate samples, showing little change after ion-irradiation whereas the titanate samples formed an amorphous surface layer ∼ 500 nm thick. While all samples had high aqueous durability, the titanate leach rate was ∼ 5 times that of the zirconate. The ion-irradiation increased the leach rate of the titanate without impurities by ∼ 5 times. The difference in the leach rates between irradiated and unirradiated zirconate samples is small. However, the zirconates were less able to incorporate impurities than the titanate ceramics and required higher sintering temperatures, ∼ 1500 C compared to 1350 C for the titanates.

  20. Extra spots in the electron diffraction patterns of neutron irradiated zirconium and its alloys

    International Nuclear Information System (INIS)

    Madden, P.K.

    1977-01-01

    Specimens of neutron irradiated zirconium and its alloys were examined in the transmission electron microscope. Groups of extra spots, often exhibiting four-fold symmetry, were observed in thin foil electron diffraction patterns of these specimens. The 'extra-spot' structure, like the expected black-dot/small scale dislocation loop neutron irradiated damage, is approximately 100 A in size. Its nature is uncertain. It may be related to irradiation damage or to some artefact introduced during specimen preparation. If it is the latter, then published irradiation damage defect size distributions and determined irradiation growth strains of other investigators, may require modification. The present inconclusive results indicate that extra-spot structure is likely to consist of oxide particles, but may correspond to hydride precipitation or decoration effects, or even, to electron beam effects. (author)

  1. Irradiation of Gemstones using Electron Beam

    International Nuclear Information System (INIS)

    Sarada Idris; Mohd Suhaimi Jusoh; Siti Aiasah Hashim

    2011-01-01

    Gemstone irradiation treatment using radiation is one of the studies conducted in the ALURTRON. The purpose of radiation is to study the effects of radiation on the gems. Through studies conducted on freshwater pearls and stones such as Topaz, Kunzite, TOURMALINE, Aquamarine, Quartz and so on, electron beam irradiation method can highlight the jewel colors but also to reduce the effects of haze on gemstones. The dose of radiation used is 25 kGy to 200 kGy. (author)

  2. DNA damage caused by UV- and near UV-irradiation

    International Nuclear Information System (INIS)

    Ohnishi, Takeo

    1986-01-01

    Much work with mutants deficient in DNA repair has been performed concerning UV-induced DNA damage under the condition where there is no artificial stimulation. In an attempt to infer the effects of solar wavelengths, the outcome of the work is discussed in terms of cellular radiation sensitivity, unscheduled DNA synthesis, and mutation induction, leading to the conclusion that some DNA damage occurs even by irradiation of the shorter wavelength light (270 - 315 nm) and is repaired by excision repair. It has been thought to date that pyrimidine dimer (PD) plays the most important role in UV-induced DNA damage, followed by (6 - 4) photoproducts. As for DNA damage induced by near UV irradiation, the yield of DNA single-strand breaks and of DNA-protein crosslinking, other than PD, is considered. The DNA-protein crosslinking has proved to be induced by irradiation at any wavelength of UV ranging from 260 to 425 nm. Near UV irradiation causes the inhibition of cell proliferation to take place. (Namekawa, K.)

  3. Irradiation damage 'displacement zone'; Dommages sous irradiation zone de deplacements

    Energy Technology Data Exchange (ETDEWEB)

    Genthon, J P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    It is well known that a charged particle (ion, primary atom, etc...) moving in a solid slows down and can cause a cascade of displacements of the atoms in the solid. A study is made here of the extent to which the cascade is made up, or not, of independent collisions, as a function of the energy of the initial charged particle. When the distance between the collisions is small, these latter are no longer independent; the cascade, which then has to be considered as a whole, perturbs and locates, in the irradiated solid , a zone which has been named a 'displacement zone'. It is shown that the proportion of displacement zones increases with increasing atom size (high atomic number Z), with decreasing atomic distance D in the substance considered and with decreasing energy of the ion undergoing the slowing down process (although always remaining above a few hundred eV). The proportions obtained are higher than those corresponding to the calculations of J. A. Brinkman [3]. An interatomic potential required for this work has also been determined. (author) [French] On sait qu'une particule chargee (ions, atomes primaires, etc...) en mouvement dans un solide se ralentit, avec eventuellement deplacement en cascade d'atomes du solide. On etudie ici dans quelle proportion, en fonction de l'energie de la particule chargee initiale, la cascade est constituee, ou non, de 'chocs independants'. Lorsque la distance entre chocs est petite, ceux-ci ne sont plus independants; la cascade, qui doit alors etre consideree dans son ensemble, perturbe et definit dans le solide irradie, une zone qu'on a appele zone de deplacements. On montre que la proportion de zones de deplacements est d'autant plus grande que les atomes sont gros (nombre atomique Z grand), que la distance interatomique D est petite dans le corps considere, et que l'energie de l'ion en ralentissement est petite (tout en restant superieure a quelques centaines d'eV). Les proportions obtenues sont superieures a celles qui

  4. Locomotor damage in rats after x-irradiation in Utero

    International Nuclear Information System (INIS)

    Mullenix, P.; Norton, S.; Culver, B.

    1975-01-01

    Alterations in gait were found in rats after whole-body irradiation with 125 R on day 14, 15, and 16 of gestation. No effects on locomotion were detected after irradiation on day 17 with 125 R or after irradiation on day 14 with 50 R. A technique was set up for quantitative evaluation of locomotion based on a modification of other methods. Walking patterns of irradiated rats were recorded, when they were adults, by requiring them to walk up a 10 0 incline through a corridor after their feet had been dipped in ink. Rats irradiated on gestational day 14 had an in-phase, hopping gait with the sine of the angle between the hind feet and the direction of progression over 0.9. Rats irradiated on gestational days 15 and 16 had an alternating, waddling gait with wider stance and broader angle than control rats. Histologic examination of serial sections of the brains of these rats showed that the 14-day rats lacked all telencephalic commissures except for a few fibers which crossed in some rats. There was a progressive improvement in the condition of the anterior and ventral hippocampal commissures up to day 17, but the corpus callosum and doral hippocampal commissure were lacking or markedly reduced in all day 17 rats. No animals showed damage to the mesencephalic posterior commissure. Since rats which used the in-phase mode of locomotion were never observed to use alternating gait, the possible causal relationship of the commissural damage to the altered locomotor patterns was considered. In view of the restricted period of damage found for the anterior and ventral hippocampal commissures and the restriction of altered locomotion to damage in the same period, primary involvement of the corpus callosum and dorsal hippocampal commissure could be excluded, but a possible role for the other telencephalic commissures remained

  5. MCNPX calculations for electron irradiated semiconductor detectors

    International Nuclear Information System (INIS)

    Sedlackova, K.; Necas, V.; Sagatova, A.; Zatko, B.

    2014-01-01

    This study aimed to treat some practical problems of (not only) semiconductor material irradiation by high energy electron beam using MCNPX simulation code. The relation between the absorbed dose and the fluency was found and the energy distribution of electron flux density was simulated on the top and back side of 270 μm thick GaAs, SiC and Si detectors. Furthermore, the dose depth profiles were calculated for GaAs, SiC and Si materials irradiated by 4 and 5 MeV electron beams. For the GaAs detector, a very good agreement with the experiment was shown. To match the absolute values of the absorbed dose with experimentally obtained values, the electron source emissivity has to be determined in relation to the electron beam setting parameters. (authors)

  6. Characterization of matrix damage in ion-irradiated reactor vessel steel

    International Nuclear Information System (INIS)

    Fujii, Katsuhiko; Fukuya, Koji

    2004-01-01

    Exact nature of the matrix damage, that is one of radiation-induced nano-scale microstructural features causing radiation embrittlement of reactor vessel, in irradiated commercial steels has not been clarified yet by direct characterization using transmission electron microscopy (TEM). We designed a new preparation method of TEM observation samples and applied it to the direct TEM observation of the matrix damage in the commercial steel samples irradiated by ions. The simulation irradiation was carried out by 3 MeV Ni 2+ ion to a dose of 1 dpa at 290degC. Thin foil specimens for TEM observation were prepared using the modified focused ion beam method. A weak-beam TEM study was carried out for the observation of matrix damage in the samples. Results of this first detailed observation of the matrix damage in the irradiated commercial steel show that it is consisted of small dislocation loops. The observed and analyzed dislocation loops have Burgers vectors b = a , and a mean image size and the number density are 2.5 nm and about 1 x 10 22 m -3 , respectively. In this experiment, all of the observed dislocation loops were too small to determine the vacancy or interstitial nature of the dislocation loops directly. Although it is an indirect method, post-irradiation annealing was used to infer the loop nature. Most of dislocation loops were stable after the annealing at 400degC for 30 min. This result suggests that their nature is interstitial. (author)

  7. Investigation of radiation damage effects in neutron irradiated CCD

    International Nuclear Information System (INIS)

    Brau, James E.; Igonkina, Olga; Potter, Chris T.; Sinev, Nikolai B.

    2005-01-01

    A Charge Coupled Devices (CCD)-based vertex detector is a leading option for vertex detection at the future linear collider. A major issue for this application is the radiation hardness of such devices. Tests of radiation hardness of CCDs used in the SLD vertex detector, VXD3, have been reported earlier. The first measurements of 1998 involved a spare VXD3 CCD that was irradiated with neutrons from a radioactive source (Pu-Be), and from a nuclear reactor. In 2003, we had the opportunity to disassemble the VXD3 detector and study the nature of the radiation damage it incurred during 3 years of operation at SLC. In the preparation for this study, additional experiments with the spare VXD3 CCD were performed. These included measurements of trapping times in neutron irradiated CCDs. Results, reported here, will help us better understand the mechanism of radiation damage effects and develop techniques to minimize performance degradation due to radiation damage

  8. Amorphization kinetics of Zr3Fe under electron irradiation

    International Nuclear Information System (INIS)

    Motta, A.T.; Howe, L.M.; Okamoto, P.R.

    1992-10-01

    0.9 MeV electron irradiations were performed at 28--220 K in a high-voltage electron microscope (HVEM). By measuring onset, spread and final size of the amorphous region, factoring in the Guassian distribution of the beam, a kinetic description of the amorphization in terms of dose, dose rate and temperature was obtained. The critical temperature for amorphization by electron irradiation was found to be ∼220 K, compared to 570--625 K for 40 Ar ion irradiation. Also, the dose-to-amorphization increased exponentially with temperature. Results indicated that the rate of growth of the amorphous region under the electron beam decreased with increasing temperature and the does-to-amorphization decreased with increasing dose rate. The size of the amorphous region saturated after a region dose, the final size decreasing with increasing temperature, and it was argued that this is related to the existence of a critical dose rate, which increased with temperature, below which no amorphization occurred. The above observations can be understood in the framework of the kinetics of damage accumulation under irradiation

  9. Electron-irradiation-induced phase transformation in alumina

    International Nuclear Information System (INIS)

    Chen, C.L.; Arakawa, K.; Lee, J.-G.; Mori, H.

    2010-01-01

    In this study, electron-irradiation-induced phase transformations between alumina polymorphs were investigated by high-resolution transmission electron microscopy. It was found that the electron-irradiation-induced α → κ' phase transformation occurred in the alumina under 100 keV electron irradiation. It is likely that the knock-on collision between incident electrons and Al 3+ cations is responsible for the occurrence of electron-irradiation-induced phase transformation from α-alumina to κ'-alumina.

  10. Comparison of electron and ion irradiation effects on order-disorder transition in Ni4Mo

    International Nuclear Information System (INIS)

    Banerjee, S.; Sundararaman, M.

    1996-01-01

    The effects of radiation damage in metals and alloys caused by electron and heavy ion beams are quite distinct from the consideration of cascade formation. Microstructural changes occurring with progressive dose of irradiation under cascade forming heavy ion irradiation and under electron irradiation have been systematically studied in Ni 4 Mo in the temperature range of 300 to 1050 K. The ordering transformation in this alloy can be used in understanding the fundamental processes of radiation damage. Conversely, radiation experiments provide an insight into the ordering mechanisms. The ordering in this alloy is governed by a competition between a second order and a first order ordering process. Steady state structures developed at different temperatures have been characterised by electron diffraction and imaging. The steady state diagrams are constructed and compared for both electron and ion irradiation. The essential difference between the nature of cascade forming and non-cascade forming irradiation on the order-disorder transformation has been discussed. (orig.)

  11. Electron beam irradiation technology for environmental conservation

    International Nuclear Information System (INIS)

    Tokunaga, Okihiro; Arai, Hidehiko; Hashimoto, Shoji

    1992-01-01

    This paper reviews research and development of application of electron beam (EB) irradiation technology for treatment of flue gas and waste water, and for disinfection of sewage sludge. Feasibility studies on EB purification of flue gases have been performed with pilot-scale experiments in Japan, the USA and Germany, and is being carried out in Poland for flue gases from iron-sintering furnaces or coal burning boilers. Based on results obtained by experiments using simulated flue gas, pilot scale test for treatment of flue gas of low-sulfur containing coal combustion has recently started in Japan. Organic pollutants in waste water and ground water have been found to be decomposed by EB irradiation. Synergetic effect of EB irradiation and ozone addition was found to improve the decomposition efficiency. Electron beam irradiation technology for disinfection of water effluent from water treatment plants was found to avoid formation of chlorinated organic compounds which are formed in using chlorine. Efficient process for composting of sewage sludge disinfected by EB irradiation has been developed by small scale and pilot scale experiments. In the new process, disinfection by EB irradiation and composing can be done separately and optimum temperature for composting can be, therefore, selected to minimize period of composting. (author)

  12. The influence of non-equilibrium fluctuations on radiation damage and recovery of metals under irradiation

    International Nuclear Information System (INIS)

    Dubinko, V.I.; Klepikov, V.F.

    2007-01-01

    In the conventional theory of radiation damage, it is assumed that the main effect of irradiation is due to formation of Frenkel pairs of vacancies and self-interstitial atoms (SIAs) and their clusters. The difference in absorption of vacancies and SIAs by primary or radiation-induced extended defects (EDs) is thought to be the main reason of microstructural evolution under irradiation. On the other hand, the recovery of radiation damage is thought to be driven exclusively by thermal fluctuations resulting in the vacancy evaporation from voids (void annealing) or dislocations (thermal creep) and in the fluctuation-driven overcoming of obstacles by gliding dislocations (plastic strain). However, these recovery mechanisms can be efficient only at sufficiently high temperatures. At lower irradiation temperatures, the main driving force of the recovery processes may be due to nonequilibrium fluctuations of energy states of the atoms surrounding EDs arising as a result of scattering of radiation-induced excitations of atomic and electronic structure at EDs. In the present paper, the mechanisms of nonequilibrium fluctuations that result in such phenomena as the void shrinkage under irradiation at low temperatures (or high dose rates), irradiation creep and irradiation-induced increase of plasticity under sub-threshold irradiation was considered

  13. AECL IMPELA electron beam industrial irradiators

    International Nuclear Information System (INIS)

    Labrie, J.P.; Drewell, N.H.; Ebrahim, N.A.; Lawrence, C.B.; Mason, V.A.; Ungrin, J.; White, B.F.

    1989-01-01

    A family of industrial irradiators is being developed by AECL to cover an electron-beam energy range from 5 to 18 MeV at beam powers between 20 and 250 kW. The IMPELA family of irradiators is designed for push button, reliable operation. The major irradiator components are modular, allowing for later upgrades to meet increased demands in either electron or X-ray mode. Interface between the control system, irradiator availability and dose quality assurance is in conformance with the most demanding specifications. The IMPELA irradiators use a klystron-driven, standing-wave, L-band accelerator structure with direct injection from a rugged, triode electron gun. Direct control of the accelerating field during the beam pulse ensures constant output beam energy, independent of beam power. The first member of the family, the IMPELA 10/50 (10 MeV, 50 kW), is in the final stages of assembly at Chalk River Nuclear Laboratories. The IMPELA 10/50 is constructed around a 3.25 m long, high-power-capacity accelerator structure operated at a duty factor of 5%. Beam loading exceeds 60%. The rf power is provided by a 2 MW/150 kW modulated-anode klystron protected from load mismatches by a circulator. This prototype will be used to demonstrate the reliability and dose uniformity targets of the IMPELA family. Full beam operation of the IMPELA 10/50 is scheduled for early 1989. (orig.)

  14. Electron microscopy at reduced levels of irradiation

    International Nuclear Information System (INIS)

    Kuo, I.A.M.

    1975-05-01

    Specimen damage by electron radiation is one of the factors that limits high resolution electron microscopy of biological specimens. A method was developed to record images of periodic objects at a reduced electron exposure in order to preserve high resolution structural detail. The resulting image would tend to be a statistically noisy one, as the electron exposure is reduced to lower and lower values. Reconstruction of a statistically defined image from such data is possible by spatial averaging of the electron signals from a large number of identical unit cells. (U.S.)

  15. Damage profiles and ion distribution in Pt-irradiated SiC

    Energy Technology Data Exchange (ETDEWEB)

    Xue, H.Z. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Zhang, Y., E-mail: Zhangy1@ornl.gov [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Zhu, Z. [Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 (United States); Zhang, W.M. [Department of Radiation Therapy, Peking University First Hospital, Beijing 100034 (China); Bae, I.-T. [Small Scale Systems Integration and Packaging Center, State University of New York at Binghamton, P.O. Box 6000, Binghamton, NY 13902 (United States); Weber, W.J. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2012-09-01

    Single crystalline 6H-SiC samples were irradiated at 150 K with 2 MeV Pt ions. The local volume swelling was determined by electron energy loss spectroscopy (EELS), and a nearly sigmoidal dependence on irradiation dose is observed. The disorder profiles and ion distribution were determined by Rutherford backscattering spectrometry (RBS), transmission electron microscopy, and secondary ion mass spectrometry. Since the volume swelling reaches 12% over the damage region at high ion fluence, the effect of lattice expansion is considered and corrected for in the analysis of RBS spectra to obtain depth profiles. Projectile and damage profiles are estimated by SRIM (Stopping and Range of Ions in Matter). When compared with the measured profiles, the SRIM code predictions of ion distribution and the damage profiles are underestimated due to significant overestimation of the electronic stopping power for the slow heavy Pt ions. By utilizing the reciprocity method, which is based on the invariance of the inelastic energy loss in ion-solid collisions against interchange of projectile and target atom, a much lower electronic stopping power is deduced. A simple approach, based on reducing the density of SiC target in SRIM simulation, is proposed to compensate the overestimated SRIM electronic stopping power values, which results in improved agreement between predicted and measured damage profiles and ion ranges.

  16. Immunological aspect of the electron-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, K [Hyogo College of Medicine, Nishinomiya (Japan)

    1978-05-01

    In the present study, sciatic nerve tissues of the cat were emulsified with the complete Freund's adjuvant and injected into the foot-pads of the guinea pig. Frozen and frozen-irradiated feline sciatic nerve tissues were treated in the similar manner, and their encephalitogenicity was comparatively studied. Affected animals became skinny, weak in the hind limbs and sometimes solid their tails. Antigenic mixtures of the fresh peripheral nerves with adjuvant have sensitized 75% (15 out of 20) of guinea pigs, whereas none of the 41 animals manifested any sign of experimental allergic neuritis (EAN) after intradermal Frozen-preserved peripheral nerve-adjuvant mixtures gave rise to EAN in 29% (6 out of 21) of guinea pigs. The present results appear to show that the electron-beam irradiation might have modified the specific chemical structures of the myelin basic protein to completely suppress the encephalitogenicity of the peripheral nerve-tissues. High-voltage cathode irradiations would be capable of depressing the antigenicity of the transplantation immunology when the antigenic determinants have the chemical structures in common with the encephalitogenic antigens. Excessive amount of the irradiation used to result in severe tissue damages, therefore, an optimum dosis of electron-beams should be determined for each tissue destined for grafting. As the frozen peripheral nerve-adjuvant mixtures have been less encephalitogenic, freezing alone might well be considered partially to improve the acceptability of the grafts. Cryopreservation of the irradiated allografts would be worth further studying.

  17. Immunological aspect of the electron-beam irradiation

    International Nuclear Information System (INIS)

    Ikeda, Kimiyuki

    1978-01-01

    In the present study, sciatic nerve tissues of the cat were emulsified with the complete Freund's adjuvant and injected into the foot-pads of the guinea pig. Frozen and frozen-irradiated feline sciatic nerve tissues were treated in the similar manner, and their encephalitogenicity was comparatively studied. Affected animals became skinny, weak in the hind limbs and sometimes solid their tails. Antigenic mixtures of the fresh peripheral nerves with adjuvant have sensitized 75% (15 out of 20) of guinea pigs, whereas none of the 41 animals manifested any sign of experimental allergic neuritis (EAN) after intradermal Frozen-preserved peripheral nerve-adjuvant mixtures gave rise to EAN in 29% (6 out of 21) of guinea pigs. The present results appear to show that the electron-beam irradiation might have modified the specific chemical structures of the myelin basic protein to completely suppress the encephalitogenicity of the peripheral nerve-tissues. High-voltage cathode irradiations would be capable of depressing the antigenicity of the transplantation immunology when the antigenic determinants have the chemical structures in common with the encephalitogenic antigens. Excessive amount of the irradiation used to result in severe tissue damages, therefore, an optimum dosis of electron-beams should be determined for each tissue destined for grafting. As the frozen peripheral nerve-adjuvant mixtures have been less encephalitogenic, freezing alone might well be considered partially to improve the acceptability of the grafts. Cryopreservation of the irradiated allografts would be worth further studying. (author)

  18. User Support of Electron Irradiation Facility

    International Nuclear Information System (INIS)

    Park, S. H.; Cha, H. K.; Lee, B. C.

    2007-06-01

    The KAERI (Korean Atomic Energy Research Institute) high-power electron beam irradiation facility, operating at the energies between 0.3 MeV and 10 MeV,has provided irradiation services to users in industries, universities, and institutes via 'Project of utilization and cooperation of users of a large research facility' since 2004. A great attraction of many researchers, almost 750 persons so far according to surveys, to e-beam irradiation technology as well as the growth of participants on Workshop on Electron Beam Applications from 121 to 176 indicate the increase of demands of irradiation service. Comparing to the cases of advanced nations in this area, such as America, Japan, China, and Russia, Korea is relatively much behind in radiation technology. It is mainly due to the lack of governmental supports and investments. Active support and investment on construction and operation of electron beam user facilities would be principal factors on developments of advanced technologies. In this project, we would like to satisfy users' requests by developing the effective managing and operating system for prompt services, processes, and QA and to ultimately assist users to create additional new results, by maximizing the utilization of all available resources and activating the developments of technologies of electron beam processing

  19. Development of an irradiation device for electron beam wastewater treatment

    International Nuclear Information System (INIS)

    Rela, Paulo Roberto

    2003-01-01

    When domestic or industrial effluents with synthetic compounds are disposed without an adequate treatment, they impact negatively the environment with damages to aquatic life and for the human being. Both population and use of goods and services that contribute for the hazardous waste are growing. Hazardous regulations are becoming more restrictive and technologies, which do not destroy these products, are becoming less acceptable. The electron beam radiation process is an advanced oxidation process, that produces highly reactive radicals resulting in mineralization of the contaminant. In this work was developed an irradiation system in order to optimize the interaction of electron beam delivered from the accelerator with the processed effluent. It is composed by an irradiation device where the effluent presents to the electron beam in an up flow stream and a process control unit that uses the calorimetric principle. The developed irradiation device has a different configuration from the devices used by others researchers that are working with this technology. It was studied the technical and economic feasibility, comparing with the literature the results of the irradiation device demonstrated that it has a superior performance, becoming an process for use in disinfection and degradation of hazardous organic compounds of wastewater from domestic and industrial origin, contributing as an alternative technology for Sanitary Engineering. (author)

  20. Response of zircon to electron and Ne+ irradiation

    International Nuclear Information System (INIS)

    Devanathan, R.; Weber, W.J.; Boatner, L.A.

    1997-01-01

    Zircon (ZrSiO 4 ) is an actinide host phase in vitreous ceramic nuclear waste forms and a potential host phase for the disposition of excess weapons plutonium. In the present work, the effects of 800 and 900 keV electron and 1 MeV Ne + irradiations on the structure of single crystals of ZrSiO 4 have been investigated. The microstructural evolution during the irradiations was studied in situ using a high-voltage electron microscope interfaced to an ion accelerator at Argonne National Laboratory. The results indicate that electron irradiation at 15 K cannot amorphize ZrSiO 4 even at fluences an order of magnitude higher than that required for amorphization by 1.5 MeV Kr + ions. However, the material is readily amorphized by 1 MeV Ne + irradiation at 15 K. The temperature dependence of this amorphization is discussed in light of previous studies of radiation damage in ZrSiO 4

  1. Irradiation damage in aluminium single crystals produced by 50-keV aluminium and copper ions

    DEFF Research Database (Denmark)

    Henriksen, L.; Johansen, A.; Koch, J.

    1968-01-01

    Aluminium single crystals, thin enough to be examined by electron microscopy, have been irradiated with 50-keV aluminium and copper ions. The irradiation fluxes were in the range 1011–1014 cm−2 s−1 and the doses were from 6 × 1012 to 6 × 1014 cm−2. Irradiation along either a or a direction produces...... rows of dislocation loops all lying parallel to one particular direction. If the aluminium target is quenched from 600 °C and annealed at room temperature prior to irradiation with aluminium ions, the rows of loops are suppressed. The amount of damage observed is considerably less than would...

  2. Thermal conductivity of electron-irradiated graphene

    Science.gov (United States)

    Weerasinghe, Asanka; Ramasubramaniam, Ashwin; Maroudas, Dimitrios

    2017-10-01

    We report results of a systematic analysis of thermal transport in electron-irradiated, including irradiation-induced amorphous, graphene sheets based on nonequilibrium molecular-dynamics simulations. We focus on the dependence of the thermal conductivity, k, of the irradiated graphene sheets on the inserted irradiation defect density, c, as well as the extent of defect passivation with hydrogen atoms. While the thermal conductivity of irradiated graphene decreases precipitously from that of pristine graphene, k0, upon introducing a low vacancy concentration, c reduction of the thermal conductivity with the increasing vacancy concentration exhibits a weaker dependence on c until the amorphization threshold. Beyond the onset of amorphization, the dependence of thermal conductivity on the vacancy concentration becomes significantly weaker, and k practically reaches a plateau value. Throughout the range of c and at all hydrogenation levels examined, the correlation k = k0(1 + αc)-1 gives an excellent description of the simulation results. The value of the coefficient α captures the overall strength of the numerous phonon scattering centers in the irradiated graphene sheets, which include monovacancies, vacancy clusters, carbon ring reconstructions, disorder, and a rough nonplanar sheet morphology. Hydrogen passivation increases the value of α, but the effect becomes very minor beyond the amorphization threshold.

  3. Polymeric materials obtained by electron beam irradiation

    International Nuclear Information System (INIS)

    Dragusin, M.; Moraru, R.; Martin, D.; Radoiu, M.; Marghitu, S.; Oproiu, C.

    1995-01-01

    Research activities in the field of electron beam irradiation of monomer aqueous solution to produce polymeric materials used for waste waters treatment, agriculture and medicine are presented. The technologies and special features of these polymeric materials are also described. The influence of the chemical composition of the solution to ba irradiated, absorbed dose level and absorbed dose rate level are discussed. Two kinds of polyelectrolytes, PA and PV types and three kinds of hydrogels, pAAm, pAAmNa and pNaAc types, the production of which was first developed with IETI-10000 Co-60 source and then adapted to the linacs built in Accelerator Laboratory, are described. (author)

  4. Irradiation damage of alkali halide crystals during positron bombardment

    International Nuclear Information System (INIS)

    Arefiev, K.P.; Arefiev, V.P.; Vorobiev, S.A.

    1978-01-01

    The bleaching effect of positron irradiation of KCl and KBr single crystals previously coloured with electrons or protons was investigated. Positrons injection in the coloured alkali halide samples reduced the F-centres concentration considerably. For KCl crystals thicker than the positrons range the appearance of additional bands in the absorption spectra is noticeable. The experimental data show that the bleaching phenomenon should be observed merely throughout the positron exposure both for irradiated and non-irradiated regions of the sample. Irradiation effects, due to positron source, on the peak counting rate of (γ-γ) angular correlation in KCl crystals under applied magnetic field were also investigated. The growth of peak counting rate shows the increase of positronium-like states formation near defects of cation sublattice. (author)

  5. Dose effects on damage of thymidylic acid and its components irradiated by A N+ ion beam

    International Nuclear Information System (INIS)

    Shao Chunlin; Yu Zengliang

    1996-08-01

    Research into damage of DNA components is an important field in mechanism study to the low energy ion beam irradiation. It was found that the UV difference spectra of irradiated thymine (T) had two positive peaks caused by the changes of π electron conjugation of the pyrimidine ring, and that the residual activity of T sample irradiated by a N + ion beam was not influenced by treatments of acid and alkali as well as heat. In addition, the residual activities of irradiated thymidine (dTR) and thymidine 5'-phosphate (5'-dTMP) with and without treating of strong acid and strong alkali were also measured. With UV absorption spectrophotometry, the yield of T released from the irradiated samples of dTR and 5'-dTMP and the residual concentration of these target molecules were deduced, and it was found that the yield of T increased when the solution of the irradiated dTR sample was treated by heat but decreased when this solution was treated by acid and alkali for these treatments splitting T-S or T-S-P. On the other hand, the yield of inorganic phosphate released from the irradiated 5'-dTMP was investigated and found that it was increased by the treatment of alkali and that the increase degree was depended on the time scale of the treatment. Moreover, G(Pi) of the irradiated 5'-dTMP non-linearly decreased with increasing dose. (10 figs.)

  6. Dependency of irradiation damage density on tritium migration behaviors in Li2TiO3

    International Nuclear Information System (INIS)

    Kobayashi, Makoto; Toda, Kensuke; Oya, Yasuhisa; Okuno, Kenji

    2014-01-01

    Tritium migration behaviors in Li 2 TiO 3 with the increase of irradiation damage density were investigated by means of electron spin resonance and thermal desorption spectroscopy. The irradiation damages of F + -centers and O − -centers were formed by neutron irradiation, and their damage densities were increased with increasing neutron fluence. Tritium release temperature was clearly shifted toward higher temperature side with increasing neutron fluence, i.e. increasing damage density. The rate determining process for tritium release was also clearly changed depending on the damage density. Tritium release was mainly controlled by tritium diffusion process in crystalline grain of Li 2 TiO 3 at lower neutron fluence. The apparent tritium diffusivity was reduced as the damage density in Li 2 TiO 3 increased due to the introduction of tritium trapping/detrapping sites for diffusing tritium. Then, tritium trapping/detrapping processes began to control the overall tritium release with further damage introductions as the amount of tritium trapping sites increased enough to trap most of tritium in Li 2 TiO 3 . The effects of water vapor in purge gas on tritium release behaviors were also investigated. It was considered that hydrogen isotopes in purge gas would be dissociated and adsorbed on the surface of Li 2 TiO 3 . Then, hydrogen isotopes diffused inward Li 2 TiO 3 would occupy the tritium trapping sites before diffusing tritium reaches to these sites, promoting apparent tritium diffusion consequently. Kinetics analysis of tritium release for highly damaged Li 2 TiO 3 showed that the rate determining process of tritium release was the detrapping process of tritium formed as hydroxyl groups. The rate of tritium detrapping as hydroxyl groups was determined by the kinetic analysis, and was comparable to tritium release kinetics for Li 2 O, LiOH and Li 4 TiO 4 . The dangling oxygen atoms (O − -centers) formed by neutron irradiation would contribute strongly on the

  7. Irreversible electron attachment--a key to DNA damage by solvated electrons in aqueous solution.

    Science.gov (United States)

    Westphal, K; Wiczk, J; Miloch, J; Kciuk, G; Bobrowski, K; Rak, J

    2015-11-07

    The TYT and TXT trimeric oligonucleotides, where X stands for a native nucleobase, T (thymine), C (cytosine), A (adenine), or G (guanine), and Y indicates a brominated analogue of the former, were irradiated with ionizing radiation generated by a (60)Co source in aqueous solutions containing Tris as a hydroxyl radical scavenger. In the past, these oligomers were bombarded with low energy electrons under an ultra-high vacuum and significant damage to TXT trimers was observed. However, in aqueous solution, hydrated electrons do not produce serious damage to TXT trimers although the employed radiation dose exceeded many times the doses used in radiotherapy. Thus, our studies demonstrate unequivocally that hydrated electrons, which are the major form of electrons generated during radiotherapy, are a negligible factor in damage to native DNA. It was also demonstrated that all the studied brominated nucleobases have a potential to sensitize DNA under hypoxic conditions. Strand breaks, abasic sites and the products of hydroxyl radical attachment to nucleobases have been identified by HPLC and LC-MS methods. Although all the bromonucleobases lead to DNA damage under the experimental conditions of the present work, bromopyrimidines seem to be the radiosensitizers of choice since they lead to more strand breaks than bromopurines.

  8. Positron lifetime studies of electron irradiated copper

    International Nuclear Information System (INIS)

    Hadnagy, T.D.

    1976-01-01

    Single-crystal copper was irradiated with 4.5-MeV electrons producing simple Frenkel defects as well as a significant concentration of divacancies. Mean positron lifetime characteristics, which are sensitive to the presence of vacancies and multivacancies in copper, was monitored after isochronal anneals between 80 and 800 0 K to determine the relative change of characteristic mean lifetimes and their associated intensities. Also a study of the dependence of the mean positron lifetime on the total electron fluence was made and compared with existing theories relating these lifetimes to vacancy or multivacancy concentrations. Numerical data from curve fitting procedures using a conventional trapping model for defect-induced changes in positron lifetimes indicate that upon irradiation with 4.5-MeV electrons at 80 0 K, about 8 percent of the defects produced are divacancy units. Divacancy units appear to be several times more effective in trapping positrons than are monovacancies. Further, the experimental data suggest that the stage III annealing processes in electron-irradiated copper most probably involve the motion and removal of both monovacancies and divacancies. A conglomerate (multivacancy) unit appears to exist as a stable entity even after annealing procedures are carried out at temperatures slightly above the stage III region. Such a stable unit could serve as a nucleation center for the appearance of voids

  9. Stress relaxation under cyclic electron irradiation

    International Nuclear Information System (INIS)

    Bystrov, L.N.; Reznitskij, M.E.

    1990-01-01

    The kinetics of deformation process in a relaxating sample under 2 MeV electron cyclic irradiation was studied experimentally. The Al-Mg alloys with controllable and different (in dislocation density precipitate presence and their character) structure were used in experiments. It was established that after the beam was switched on the deformation rate increased sharply and then, during prolonged irradiation, in a gradual manner. After the switching-off the relaxation rate decreases by jumps up to values close to extrapolated rates of pre-radiation relaxation. The exhibition of these effects with radiation switching-off and switchin-on is dependent on the initial rate of thermal relaxation, the test temperature, the preliminary cold deformation and the dominating deformation dislocation mechanism. The preliminary cold deformation and test temperature elevation slightly decrease the effect of instantaneous relaxation acceleration with the irradiation switch-on. 17 refs., 5 figs

  10. Characterisation of neutron irradiation damage in zirconium alloys - a 'Round Robin' experiment

    International Nuclear Information System (INIS)

    Kelly, P.M.; Blake, R.G.; Jostsons, A.

    1977-01-01

    The nature of the damage structure in the neutron-irradiated zirconium specimens supplied as part of an international 'Round Robin' experiment has been studied using transmission electron microscopy. The damage structure consists entirely of a/3 dislocation loops and no evidence has been found for c component loops. Both vacancy and interstitial loops were found in specimens where inside/outside contrast analysis was possible. Quantitative measurements of loop size distributions and loop concentrations are reported. All specimens exhibited corduroy contrast to varying degress. (author)

  11. Ion-irradiation studies of cascade damage in metals

    International Nuclear Information System (INIS)

    Averback, R.S.

    1982-03-01

    Ion-irradiation studies of the fundamental aspects of cascade damage in metals are reviewed. The emphasis of these studies has been the determination of the primary state of damage (i.e. the arrangement of atoms in the cascade region prior to thermal migration of defects). Progress has been made towards understanding the damage function (i.e. the number of Frenkel pairs produced as a function of primary recoil atom energy), the spatial configuration of vacancies and interstitials in the cascade and the cascade-induced mixing of atoms. It is concluded for these studies that the agitation of the lattice in the vicinity of energetic displacement cascades stimulates the defect motion and that such thermal spike motion induces recombination and clustering of Frenkel defects. 9 figures

  12. Clustered DNA damage induced by proton and heavy ion irradiation

    International Nuclear Information System (INIS)

    Davidkova, M.; Pachnerova Brabcova, K; Stepan, V.; Vysin, L.; Sihver, L.; Incerti, S.

    2014-01-01

    Ionizing radiation induces in DNA strand breaks, damaged bases and modified sugars, which accumulate with increasing density of ionizations in charged particle tracks. Compared to isolated DNA damage sites, the biological toxicity of damage clusters can be for living cells more severe. We investigated the clustered DNA damage induced by protons (30 MeV) and high LET radiation (C 290 MeV/u and Fe 500 MeV/u) in pBR322 plasmid DNA. To distinguish between direct and indirect pathways of radiation damage, the plasmid was irradiated in pure water or in aqueous solution of one of the three scavengers (coumarin-3-carboxylic acid, dimethylsulfoxide, and glycylglycine). The goal of the contribution is the analysis of determined types of DNA damage in dependence on radiation quality and related contribution of direct and indirect radiation effects. The yield of double strand breaks (DSB) induced in the DNA plasmid-scavenger system by heavy ion radiation was found to decrease with increasing scavenging capacity due to reaction with hydroxyl radical, linearly with high correlation coefficients. The yield of non-DSB clusters was found to occur twice as much as the DSB. Their decrease with increasing scavenging capacity had lower linear correlation coefficients. This indicates that the yield of non-DSB clusters depends on more factors, which are likely connected to the chemical properties of individual scavengers. (authors)

  13. Electron beam irradiation induces abnormal development and the stabilization of p53 protein of American serpentine leafminer, Liriomyza trifolii (Burgess)

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Hyun-Na; Yun, Seung-Hwan; Yoon, Changmann [Department of Plant Medicine, College of Agriculture, Life and Environment Sciences, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Kim, Gil-Hah, E-mail: khkim@chungbuk.ac.kr [Department of Plant Medicine, College of Agriculture, Life and Environment Sciences, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)

    2012-01-15

    The American serpentine leafminer fly, Liriomyza trifolii (Burgess), is one of the most destructive polyphagous pests worldwide. In this study, we determined electron beam doses for inhibition of normal development of the leaf miner and investigated the effect of electron beam irradiation on DNA damage and p53 stability. Eggs (0-24 h old), larvae (2nd instar), puparia (0-24 h old after pupariation) and adults (24 h after emergence) were irradiated with increasing doses of electron beam irradiation (six levels between 30 and 200 Gy). At 150 Gy, the number of adults that developed from irradiated eggs, larvae and puparia was lower than in the untreated control. Fecundity and egg hatchability decreased depending on the doses applied. Reciprocal crosses between irradiated and unirradiated flies demonstrated that males were more radiotolerant than females. Adult longevity was not affected in all stages. The levels of DNA damage in L. trifolii adults were evaluated using the alkaline comet assay. Our results indicate that electron beam irradiation increased levels of DNA damage in a dose-dependent manner. Moreover, low doses of electron beam irradiation led to the rapid appearance of p53 protein within 6 h; however, it decreased after exposure to high doses (150 Gy and 200 Gy). These results suggest that electron beam irradiation induced not only abnormal development and reproduction but also p53 stability caused by DNA damage in L. trifolii. We conclude that a minimum dose of 150 Gy should be sufficient for female sterilization of L. trifolii. - Highlights: > Electron beam irradiation inhibited normal development of the leaf miner. > Electron beam irradiation inhibited normal reproduction of the leaf miner. > Electron beam irradiation increased levels of DNA damage. > Electron beam irradiation induced p53 stability.

  14. Exhaust gas treatment by electron beam irradiation

    International Nuclear Information System (INIS)

    Shibamura, Yokichi; Suda, Shoichi; Kobayashi, Toshiki

    1991-01-01

    Among global environmental problems, atmospheric pollution has been discussed since relatively old days, and various countermeasures have been taken, but recently in connection with acid rain, the efficient and economical treatment technology is demanded. As the denitration and desulfurization technology for the exhaust gas from the combustion of fossil fuel, the incineration of city trash and internal combustion engines, three is the treatment method by electron beam irradiation. By irradiating electron beam to exhaust gas, nitrogen oxides and sulfur oxides are oxidized to nitric acid and sulfuric acid, and by promoting the neutralization of these acids with injected alkali, harmless salts are recovered. This method has the merit that nitrogen oxides and surfur oxides can be removed efficiently with a single system. In this report, as for the exhaust gas treatment by electron beam irradiation, its principle, features, and the present status of research and development are described, and in particular, the research on the recent exhaust gas treatment in city trash incineration is introduced. This treatment method is a dry process, accordingly, waste water disposal is unnecessary. The reaction products are utilized as fertilizer, and waste is not produced. (K.I.)

  15. Electron beam irradiation effects on carbon fiber reinforced PEEK composite

    International Nuclear Information System (INIS)

    Sasuga, Tsuneo; Hagiwara, Miyuki; Odajima, Tosikazu; Sakai, Hideo; Nakakura, Toshiyuki; Masutani, Masahiro.

    1987-03-01

    Carbon fiber(CF) reinforced composites, using polyarylether-sulfone (PES) or polyarylether-ether-ketone (PEEK) as matrix material, were prepared and their electron beam irradiation effects were studied on the basis of changes in mechanical and dynamic viscoelastic properties and observation of fracture surfaces. The flexural strength of PES-CF composite decreased to 70 % of the initial strength after the irradiation of 3 MGy and 40 % after 15 MGy. The change in the profile of stress-strain (S-S) curves and fractographic observation by electron microscopy indicated that this composite irradiated with over 3 MGy was fractured by delamination caused by to the degradation of matrix polymer. The mechanical properties of PEEK-CF composite were scarcely decreased even after irradiated up to 180 MGy and this composite showed very high radiation resistance. The change in the profile of S-S curves and fractographic observation showed that this composite fractured due to destruction of fiber in the dose range less than 180 MGy, indicating that PEEK was excellent matrix material used in high radiation field. PEEK-PES-CF composite which was composed of the carbon fibers coated with PES solution showed less radiation resistance compared with PEEK-CF composite; the flexural strength decreased to 85 % of the initial value after the irradiation with 90 MGy. It was revealed from the changes in the profile of S-S curve that the specimen irradiated over 120 MGy was fractured due to not only fiber destruction but delamination. Deterioration mechanism of PEEK-PES-CF composite was studied by dynamic viscoelastic measurements in connection with the damage on matrix-fiber interface. It was suggested that the deterioration in mechanical properties of this composite was caused by the degradation of PES that coated on the surface of the carbon fibers. (author)

  16. Electron irradiation effects on lithium peroxide

    Science.gov (United States)

    Kikkawa, Jun; Shiotsuki, Taishi; Shimo, Yusuke; Koshiya, Shogo; Nagai, Takuro; Nito, Takehiro; Kimoto, Koji

    2018-03-01

    In this study, electron irradiation effects on lithium peroxide (Li2O2), which is an important discharge product of Li-air (or Li-O2) batteries, were investigated using selected-area electron diffraction (SAED) and high-energy resolution electron energy-loss spectroscopy (EELS). The results obtained show that Li2O2 to Li2O transformation occurs with 80 and 300 keV incident electrons under high electron dose rates at 20 and -183 °C. The Li2O2 to Li2O transformation rate for 300 keV was 1/5 of that for 80 keV with the irradiation taking place at -183 °C. We also present a series of the EELS spectra that can be used as a criterion to judge the molar ratio of Li2O to Li2O2 in the general systems where Li2O2 and Li2O coexist.

  17. Radiation damage in stainless steel under varying temperature neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Naoaki [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics

    1998-03-01

    Microstructural evolution of model alloys of 316SS was examined by neutron irradiation at JMTR under cyclic temperature varying condition. In the case of Fe-16Cr-17Ni, formation of interstitial loops and voids are strongly suppressed by varying the temperature from 473K to 673K. By adding Ti as miner element (0.25wt%), however, abnormal accumulation of vacancies (void swelling of 11%dpa at 0.1dpa) was observed. Theoretical analysis standing on the rate theory of defect clustering and simulation irradiation experiments with heavy ions indicates that the vacancy-rich condition which appears temporally during and after changing the temperature from low to high brings these results. It was also shown that only 1 dpa pre-irradiation at low temperature changes swelling behavior at high temperature above several 10 dpa. The understanding of non-steady-state defect processes under temperature varying irradiation is very important to estimate the radiation damage under fusion environment where short-term and long-term temperature variation is expected. (author)

  18. UVA Irradiation of Dysplastic Keratinocytes: Oxidative Damage versus Antioxidant Defense

    Science.gov (United States)

    Nechifor, Marina T.; Niculiţe, Cristina M.; Urs, Andreea O.; Regalia, Teodor; Mocanu, Mihaela; Popescu, Alexandra; Manda, Gina; Dinu, Diana; Leabu, Mircea

    2012-01-01

    UVA affects epidermal cell physiology in a complex manner, but the harmful effects have been studied mainly in terms of DNA damage, mutagenesis and carcinogenesis. We investigated UVA effects on membrane integrity and antioxidant defense of dysplastic keratinocytes after one and two hours of irradiation, both immediately after exposure, and 24 h post-irradiation. To determine the UVA oxidative stress on cell membrane, lipid peroxidation was correlated with changes in fatty acid levels. Membrane permeability and integrity were assessed by propidium iodide staining and lactate dehydrogenase release. The effects on keratinocyte antioxidant protection were investigated in terms of catalase activity and expression. Lipid peroxidation increased in an exposure time-dependent manner. UVA exposure decreased the level of polyunsaturated fatty acids, which gradually returned to its initial value. Lactate dehydrogenase release showed a dramatic loss in membrane integrity after 2 h minimum of exposure. The cell ability to restore membrane permeability was noted at 24 h post-irradiation (for one hour exposure). Catalase activity decreased in an exposure time-dependent manner. UVA-irradiated dysplastic keratinocytes developed mechanisms leading to cell protection and survival, following a non-lethal exposure. The surviving cells gained an increased resistance to apoptosis, suggesting that their pre-malignant status harbors an abnormal ability to control their fate. PMID:23222638

  19. Use of electron accelerators in food irradiation

    International Nuclear Information System (INIS)

    Sanyal, Bhaskar

    2013-01-01

    Preservation of food by ionizing radiations involves controlled application of energy of radiation to agricultural commodities, foods and food ingredients, for improving storage life, hygiene and safety. Insects and microbes cause major economic losses to stored crops. Many of our food products are contaminated with diseases causing germs and toxin producing molds. Without improvement in microbial quality and getting properly treated to overcome quarantine barriers our agricultural products cannot get international markets. In this respect electron accelerators have immense potential in commercial radiation processing of foods. Both low and high dose applications with increased process rates can be achieved using accelerators to cover a wide spectrum of food commodities approved for commercial radiation processing as per the recent gazette notification under Atomic Energy (Radiation Processing of Food and Allied Products) Rule, 2012. The effectiveness of processing of food by ionizing radiation depends on proper delivery of absorbed dose and its reliable measurement. For food destined for international trade, it is important that the dosimetry used for dose determination is carried out accurately and that the process is monitored in accordance with the internationally accepted procedures. Experiments using alanine-EPR system were carried out to optimize the process parameters of 10 MeV electron beam for commercial irradiation of food. Different food commodities namely, mango, potato and rawa (semolina) were irradiated to measure the absorbed dose distribution. The actual depth dose profile in food products and useful scan width of the electron beam were determined for commercial radiation processing of food using electron beam. (author)

  20. Determination of the electron beam irradiated area

    International Nuclear Information System (INIS)

    Zarbout, K.; Kallel, A.; Moya, G.

    2005-01-01

    The investigation of the charge trapping properties of non-conductive materials open the way to an understanding of the degradation of their characteristics due to ageing and catastrophic phenomena, such as breakdown, which originate from the rapid relaxation of trapped charges. The defects, in particular those introduced during the fabrication process, are responsible for the charging phenomena which limit the technological performances and the reliability of these materials. Several characterisation techniques have been developed and among them the one which uses the electron beam of the scanning Electron Microscope (SEM). The study of the charge trapping properties in non-conductive solids by using the electron beam of a SEM requires the knowledge of the current beam and injected charges densities. These densities depend on the irradiated sample area. For this reason, we report in this work two experimental procedures allowing a direct determination of the irradiated area size by the incident defocused beam. The first is based on the charging effect of oxide surfaces (SiO2, MgO, AL2O3) and the second is derived from the electron beam lithography technique. The latter procedure constitutes a convenient experimental method

  1. Radiation damage in proton-irradiated epitaxial silicon detectors

    International Nuclear Information System (INIS)

    Lange, Joern

    2009-07-01

    In this work radiation hardness of 75 μm, 100 μm and 150 μm thick epitaxial silicon pad diodes of both standard and oxygenated material was investigated. Damage after 24 GeV/c proton irradiation in a 1MeV neutron equivalent fluence range between 10 14 cm -2 and 10 16 cm -2 was studied and isothermal annealing experiments at 80 C were carried out. Standard CV/IV measurements could be performed up to 4 x 10 15 cm -2 . The volume-normalised reverse current was found to increase linearly with fluence with a slope independent of the thickness and impurity concentration. However, due to large fluctuations the fluences had to be renormalised using the current-related damage parameter. Concerning the depletion voltage, nearly all materials remained at a moderate level up to 4 x 10 15 cm -2 . During short-term annealing acceptors annealed out, whereas others were introduced during the long-term annealing. The stable damage was characterised by donor removal at low fluences and fluence-proportional predominant donor introduction for highly irradiated diodes, depending on the oxygen level. No type inversion was observed. Time-resolved measurements with a new 670 nm laser-TCT setup made the determination of the trapping time constant with the charge correction method possible. The results agreed with expectations and showed a linear increase of trapping probability with fluence. The electric field exhibited a double peak structure in highly irradiated diodes. Charge collection efficiency measurements with α-particles were independent of oxygen concentration, but showed an improved efficiency for thinner diodes. A comparison to simulation revealed systematic discrepancies. A non-constant trapping time parameter was proposed as possible solution. (orig.)

  2. Radiation damage in proton-irradiated epitaxial silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lange, Joern

    2009-07-15

    In this work radiation hardness of 75 {mu}m, 100 {mu}m and 150 {mu}m thick epitaxial silicon pad diodes of both standard and oxygenated material was investigated. Damage after 24 GeV/c proton irradiation in a 1MeV neutron equivalent fluence range between 10{sup 14} cm{sup -2} and 10{sup 16} cm{sup -2} was studied and isothermal annealing experiments at 80 C were carried out. Standard CV/IV measurements could be performed up to 4 x 10{sup 15} cm{sup -2}. The volume-normalised reverse current was found to increase linearly with fluence with a slope independent of the thickness and impurity concentration. However, due to large fluctuations the fluences had to be renormalised using the current-related damage parameter. Concerning the depletion voltage, nearly all materials remained at a moderate level up to 4 x 10{sup 15} cm{sup -2}. During short-term annealing acceptors annealed out, whereas others were introduced during the long-term annealing. The stable damage was characterised by donor removal at low fluences and fluence-proportional predominant donor introduction for highly irradiated diodes, depending on the oxygen level. No type inversion was observed. Time-resolved measurements with a new 670 nm laser-TCT setup made the determination of the trapping time constant with the charge correction method possible. The results agreed with expectations and showed a linear increase of trapping probability with fluence. The electric field exhibited a double peak structure in highly irradiated diodes. Charge collection efficiency measurements with {alpha}-particles were independent of oxygen concentration, but showed an improved efficiency for thinner diodes. A comparison to simulation revealed systematic discrepancies. A non-constant trapping time parameter was proposed as possible solution. (orig.)

  3. Experimental investigations of chromosomal aberrations following irradiation with fast electrons at various irradiation depths as influenced by sulfoguanidine

    International Nuclear Information System (INIS)

    Donnerstag, R.

    1975-01-01

    Root tips of Vicia faba were irradiated with fast electrons (14.2 MeV, 120 rad) in the phantom at a depth of 100% and 30% relative depth dose in culture medium and sulphoguanidine solution and were fixed after 3, 6, 9, 12 and 24 h. In contrast to the controls, a transitory mitotic depression was observed after irradiation. This effect was more marked for root tips irradiated in culture medium and much less pronounced in root tips irradiated in sulphoguanidine. When quantitatively assessing the anaphasal aberrations, the highest damage rate was found at 3 h p.r. This was attributed to the facts that these cells had been irradiated in the earliest G 2 phase. A second aberration peak was found 9 h after irradiation at 30% relative depth dose. These cells had been irradiated in the middle of the S phase. It is assumed that with increasing LET, euchromatic DNA regions are most readily damaged. When the two irradiation depths were compared, it was found that the aberration rate was significantly reduced after irradiation in sulphoguanidine solution at a depth of 30% relative dose. A qualitative assessment showed that fragments made up the highest and bridges the lowest fraction of aberrations, although there were variations in the single values depending on the irradiation conditions and culture media used. It was assumed that sulfoguanidine may have a positive influence on repair processes in damaged DNA, and that this influence depends on the energy spectrum of the irradiation. Furthermore, the possibility of a biochemical mechanism was discussed. (orig./MG) [de

  4. Commercializing ALURTRONs electron beam irradiation services

    International Nuclear Information System (INIS)

    Siti Aiasah Hashim; Mohd Sidek Othman; Shari Jahar; Sarada Idris; Naurah Mohd Isa; Muhamad Zahidee Taat

    2010-01-01

    ALURTRON has been the nation's sole electron irradiation service provider for research sectors. The main irradiation is done by utilising the EPS 3000 Cockcroft-Walton type 3.0 MeV, 90 k Watts electron beam machine (EBM). With more than 15 years experience in the operation and maintenance of the EPS, the challenge is now to commercialize the service at a larger and profitable scale. Medical products sterilization at commercial level has been ruled out since the energy is insufficient to penetrate dense and non-homogenous items. Recently, the demand for irradiation of wire and heat shrinkable tubes is showing bigger commercial potential. Therefore, prudent planning considerations need to be taken to ensure profitable return to the agency. Calculations were made to estimate ALURTRON service capacity, based on the existing EBM and its auxiliary systems. Details of the calculation including all the variables are presented. Results indicated that Alurtron should be able to process a minimum of 1000 km of small wires per month, running at 150 m/ min, working in two shifts, 5 days a week. The projected revenue is dependent on the charges imposed on the basis of total length delivered. (author)

  5. Electron beam irradiation experiments of monoblock divertor mock-up

    International Nuclear Information System (INIS)

    Satoh, Kazuyoshi; Akiba, Masato; Araki, Masanori; Suzuki, Satoshi; Yokoyama, Kenji; Smid, I.; Cardella, A.; Duwe, R.; Di Pietro, E.

    1993-03-01

    It is one of the key issues for ITER to develop the divertor plate. Electron beam irradiation tests were carried out on a NET divertor mock-up using JEBIS at JAERI under a collaboration between The NET team, JAERI and KFA Juelich. Screening tests (maximum heat flux of 23 MW/m 2 ) and thermal cycling tests (18 MW/m 2 , 30s, 1000cycle) were carried out. As a result of the screening tests, the erosion caused by sublimation of C/C was observed on the surface of armor tile. No serious damage such as cracks or detachments, however, were found. As a result of the thermal cycling tests, no major damage was detected on the C/C surface. However cooling time constant of the divertor mock-up increased over 600cycle. Therefore it implies that some defects would occur at the brazing interface of the divertor mock-up. (author)

  6. Positron annihilation in hydrogenated and electron-irradiated titanium alloys

    International Nuclear Information System (INIS)

    Mukashev, K.M.; Zaikin, Yu.A.

    2002-01-01

    Important information on hydrogen behavior in titanium can be obtained from studies of radiation damage in previously hydrogenated metal. For this purpose annealed titanium samples were hydrogenated at the temperature 500 deg. C during 1 hour. Then both the original annealed samples and hydrogenated samples were irradiated by 4 MeV electrons in the fluence range 3·10 7 -1·10 19 cm - 2 at the temperature 60 deg. C. It is known that electron irradiation in these conditions predominantly creates vacancy-type defects with an average radius R ν =0.81 Angstrom. It was stated that annihilation probability after electron irradiation of previously hydrogenated titanium samples always has some intermediate values between those characteristic for hydrogenated and irradiated states of previously annealed metal. This is a reason to suppose that radiation defects of the vacancy type in previously hydrogenated titanium combine with hydrogen atoms in favorable conditions of their partial ionization. The estimated value of the average radius for such a complex is R ν =1.1 Angstrom, that is higher than vacancy size but lower than an atom radius. No dose dependence of hydrogen interaction with radiation defects was observed in our experiments.The results of isochrone annealing of the materials under study have shown that the single annealing recovery stage with activation energy E a equal to 1.22 eV is observed in electron irradiated but not previously hydrogenated titanium in the temperature range 170-240 deg. C. Electron irradiation of the previously hydrogenated metal shifts beginning of the first recovery stage to the temperature about 225-230 deg. C and finishes near the temperature 330 deg. C. Therefore, the bound state vacancy-hydrogen in titanium is characterized by higher temperature range of dissociation and annealing with activation energy equal to 1.38 eV. However, subsequent measurements, of the angular distribution of annihilation photons (ADAP) have demonstrated

  7. WEBEXPIR: Windowless target electron beam experimental irradiation

    International Nuclear Information System (INIS)

    Dierckx, Marc; Schuurmans, Paul; Heyse, Jan; Rosseel, Kris; Tichelen, Katrien Van; Nactergal, Benoit; Vandeplassche, Dirk; Aoust, Thierry; Abs, Michel; Guertin, Arnaud; Buhour, Jean-Michel; Cadiou, Arnaud; Abderrahim, Hamid Ait

    2008-01-01

    The windowless target electron beam experimental irradiation (WEBEXPIR) program was set-up as part of the MYRRHA/XT-ADS R and D effort on the spallation target design to investigate the interaction of a proton beam with a liquid lead-bismuth eutectic (LBE) free surface. In particular, possible free surface distortion or shockwave effects in nominal conditions and during sudden beam on/off transient situations, as well as possible enhanced evaporation were assessed. An experiment was conceived at the IBA TT-1000 Rhodotron, where a 7 MeV electron beam was used to simulate the high power deposition at the MYRRHA/XT-ADS LBE free surface. The geometry and the LBE flow characteristics in the WEBEXPIR set-up were made as representative as possible of the actual situation in the MYRRHA/XT-ADS spallation target. Irradiation experiments were carried out at beam currents of up to 10 mA, corresponding to 40 times the nominal beam current necessary to reproduce the MYRRHA/XT-ADS conditions. Preliminary analyses show that the WEBEXPIR free surface flow was not disturbed by the interaction with the electron beam and that vacuum conditions stayed well within the design specifications

  8. Krypton and helium irradiation damage in neodymium-zirconolite

    International Nuclear Information System (INIS)

    Gilbert, M.; Davoisne, C.; Stennett, M.; Hyatt, N.; Peng, N.; Jeynes, C.; Lee, W.E.

    2011-01-01

    A leading candidate for the immobilisation of actinides, zirconolite's suitability as a potential ceramic host for plutonium disposition, both in storage and geological disposal, has been the subject of much research. One key aim of this study is to understand the effects of radiation damage and noble gas accommodation within the zirconolite material. To this end, a series of ex situ irradiations have been performed on polycrystalline (Ca 0.8 Nd 0.2 )Zr(Ti 1.8 Al 0.2 )O 7 zirconolite samples. Zirconolite samples, doped with Nd 3+ (as a Pu surrogate) on the Ca-site and charge-balanced by substituting Al 3+ onto the Ti-site, were irradiated with 36 Kr + (2 MeV) ions at fluences of 1 x 10 14 and 5 x 10 15 cm -2 and 4 He + (200 keV) ions at fluences of 1 x 10 14 , 5 x 10 15 and 1 x 10 17 cm -2 to simulate the impact of alpha decay on the microstructure. Microstructural analysis revealed no damage present at the lower Kr + fluence, but that the higher 36 Kr + fluence rendered the zirconolite completely amorphous. Similarly, evidence of helium accumulation was only seen at the highest 4 He + fluence (1 x 10 17 cm -2 ). Monte Carlo simulations using the TRIM code predict the highest concentration of helium accumulating at a depth of 720 nm, in good agreement with the experimental observations.

  9. Lack of correlation between villus and crypt damage in irradiated mouse intestine

    International Nuclear Information System (INIS)

    Carr, K.E.; Hamlet, R.; Nias, A.H.W.; Watt, C.

    1979-01-01

    It has been observed that scanning electron microscopy is a more sensitive indicator of mucosal damage at low radiation dose levels than conventional quantitative crypt counting techniques. Three different fractionation schedules were subjected to investigation by both of these methods to try and elucidate some features of irradiation damage to the whole of the intestinal mucosa, at dose levels commonly used in clinical practice. Despite variations in the qualitative observations, there was a marked difference in two of the schedules between damage expressed as crypt counts and that described by the qualitative techniques. In the first case high crypt numbers were associated with severe mucosal damage, whereas the second schedule produced a reduced crypt count in association with low damage to the surface mucosa. A third schedule produced results in which there was a general agreement between low crypt numbers and considerable surface mucosal damage. However, observations were made of mucosal formations not previously seen on damaged mucosa; surfaces. These resembled the appearance normally associated with the gut of patients suffering from coeliac disease. Variations in the qualitative observations were seen in the schedules so that their interpretation in terms of perturbation of cellular kinetics is difficult. (author)

  10. Experimental investigations on chronic irradiation damage of the heart

    International Nuclear Information System (INIS)

    Lauk, S.

    1984-02-01

    Irradiation of rat hearts induced the following clinical phenomena: increasingly severe dyspnea, associated flank respiration and deterioration of the general condition bordering on a prefinal syndrome. Dissection of the sick animals and thoracal x-rays taken regularly revealed extensive pesicardial and pleural effusions. The tissue of the pericardium was thickened and edematous. The most striking histological finding consisted in a focal degeneration and destruction of the myocardium without an increase in collagenous fibres. This damage to the heart muscle was quite severe and seen in all dose groups from 15 to 40 Gy. At the same time there was a reduction of the capillary density as a function of the radiation dose. Clinical symptoms were also observed in animals irradiated with 10 Gy only. All animals irradiated with at least 20 Gy, attained a state where death was imminent. Consequently, the LD-50 must be lower than 20 Gy. The latency period was over a year at 15 Gy but decreased considerably as the dose increased. (orig.) [de

  11. Irradiation damage behavior of low alloy steel wrought and weld materials

    International Nuclear Information System (INIS)

    Stofanak, R.J.; Poskie, T.J.; Li, Y.Y.; Wire, G.L.

    1993-01-01

    A study was undertaken to evaluate the irradiation damage response of several different types of low alloy steel: vintage type ASTM A302 Grade B (A302B) plates and welds containing different Ni and Cu concentrations, 3.5% Ni steels similar to ASTM A508 Class 4, welds containing about 1% Ni (similar to type 105S), and 3.5% Ni steels with ''superclean'' composition. All materials were irradiated at several different irradiation damage levels ranging from 0.0003 to 0.06 dpa at 232C (450F). Complete Charpy V-notch impact energy transition temperature curves were generated for all materials before and after irradiation to determine transition temperature at 4IJ (30 ft-lb) or 47J (35 ft-lb) and the upper shelf energy. Irradiation damage behavior was measured by shift in Charpy 41J or 47J transition temperature (ΔTT4 41J or ΔTT 47J ) and lowering of upper shelf Charpy energy at a given irradiation damage level. It was found that chemical composition greatly influenced irradiation damage behavior; highest irradiation damage (greatest ΔTT) was found in an A302B type weld containing 1.28% Ni and 0.20% Cu while the least damage was found in 3.5% Ni, 0.05% Cu, superclean wrought materials. Combination of Ni and Cu was found to affect irradiation damage behavior at higher irradiation damage levels in the A302B welds where the 1.28% Ni, 0.20% Cu weld showed more damage than a 0.60% Ni, 0.31% Cu weld. For the 3.5% Ni steels, fabrication influenced irradiation behavior in that a silicon (Si) killed material showed greater irradiation damage than a low silicon material. In general, the 3.5% Ni materials with low copper showed less irradiation damage than the A302B materials

  12. Electron beam irradiation of fluoropolymers containing polyethers

    Science.gov (United States)

    Bucio, E.; Burillo, G.; Tapia, F.; Adem, E.; Cedillo, G.; Cassidy, P. E.

    2009-02-01

    A highly fluorinated monomer, 1,3-bis(1,1,1,3,3,3-hexafluoro-2-pentafluorophenyl methoxy-2-propyl)benzene (12F-FBE) was polymerized with some diphenols by polycondensation and then was electron beam irradiated between 100 and 1000 kGy to determine degradation radiochemistry yield ( Gs) by gel permeation chromatography (GPC). The samples were characterized after irradiation by DSC, FTIR, and nuclear magnetic resonance (NMR). The fluoropolymers show apparent degradation in mechanical properties at 300 kGy, except 12F-FBE polymerized with biphenol and bisphenol A, when they did not show any apparent physical change up to 300 kGy; and continue to be flexible and transparent, with a radiochemical yield scission ( Gs) of 0.75, 0.53, 0.88, and 0.38 for 12F-FBE/SDL aliphatic, 12F-FBE/biphenol, 12F-FBE/bisphenol A, and 12F-FBE/bisphenol O, respectively. The number average molecular weights for three of the polymers decrease upon 1000 kGy irradiation to 10% of their original values; however, the polymer from bisphenol A is much more stable and its Mn decreases to only 24% of original.

  13. Electron beam irradiation of fluoropolymers containing polyethers

    International Nuclear Information System (INIS)

    Bucio, E.; Burillo, G.; Tapia, F.; Adem, E.; Cedillo, G.; Cassidy, P.E.

    2009-01-01

    A highly fluorinated monomer, 1,3-bis(1,1,1,3,3,3-hexafluoro-2-pentafluorophenyl methoxy-2-propyl)benzene (12F-FBE) was polymerized with some diphenols by polycondensation and then was electron beam irradiated between 100 and 1000 kGy to determine degradation radiochemistry yield (G s ) by gel permeation chromatography (GPC). The samples were characterized after irradiation by DSC, FTIR, and nuclear magnetic resonance (NMR). The fluoropolymers show apparent degradation in mechanical properties at 300 kGy, except 12F-FBE polymerized with biphenol and bisphenol A, when they did not show any apparent physical change up to 300 kGy; and continue to be flexible and transparent, with a radiochemical yield scission (G s ) of 0.75, 0.53, 0.88, and 0.38 for 12F-FBE/SDL aliphatic, 12F-FBE/biphenol, 12F-FBE/bisphenol A, and 12F-FBE/bisphenol O, respectively. The number average molecular weights for three of the polymers decrease upon 1000 kGy irradiation to 10% of their original values; however, the polymer from bisphenol A is much more stable and its M n decreases to only 24% of original

  14. FTIR spectroscopy of electron irradiated polymers

    International Nuclear Information System (INIS)

    Finch, D.S.

    1988-04-01

    The chemical changes in electron beam irradiated polymers, in particular PVC, are considered in order to relate the formation of conjugated structures to changes in the electrical properties. Infrared spectroscopy has been used to measure these changes. Fourier Transform techniques and computing facilities make better data processing possible. A method for base line interpretation is demonstrated whereby a shift parallel to the abscisal axis in a region of the polymer that is non absorbing is used to evaluate the baseline. This technique has proved to be highly reproducible providing that the polymer films to be examined are optically homogeneous. Evaluation of the rate of decay of the total area of the carbon chlorine region of the polymer has been compared with the chlorine decay curve analysed by the measurement of x-ray emission during irradiation of bulk samples. The significant reduction in the evolution of atomic chlorine through x-ray analysis has been attributed to the trapping of HCl within the polymer film and its subsequent slow diffusion out of the polymer. With PVC, one of the main products as a result of irradiation is the formation of conjugated sequences. These were studied by the use of uv-visible spectroscopy. (author)

  15. Windowless Electron Beam Experimental Irradiation WEBExplr

    International Nuclear Information System (INIS)

    Heyse, J.

    2009-01-01

    The design of the MYRRHA/XT-ADS, the European eXperimental Accelerator Driven System for the demonstration of Transmutation, includes a high power windowless spallation target operating with liquid LBE (Lead-Bismuth Eutectic) that will be irradiated with a 600 MeV proton beam at currents of up to 2.5 mA. When considering such a high power windowless target design, a number of questions need to be addressed, such as the stability of the free surface flow and its ability to remove the power deposited by the proton beam by forced convection, the compatibility of a large hot LBE reservoir with the beam line vacuum and the outgassing of the LBE in the spallation target circuit. These issues have been studied during previous experiments supported by numerical simulations. Another crucial point in the development of the spallation target is the demonstration of the safe and stable operation of the free LBE surface during irradiation with a high power proton beam. As a first step in this program, the WEBExpIr (Windowless target Electron Beam Experimental Irradiation) experiment was set up. The purpose of the WEBExpIr experiment was to investigate the influence of LBE surface heating caused by a charged particle beam in a situation representative of the MYRRHA/XT-ADS. More in particular, we wanted to assess possible free surface distortion or shockwave effects in nominal conditions and during sudden beam on/off transient situations, as well as possible enhanced evaporation

  16. Cerenkov light and the production of photoreactivatable damage in X-irradiated E. coli

    International Nuclear Information System (INIS)

    Redpath, J.L.; Zabilansky, E.; Morgan, T.; Ward, J.F.

    1981-01-01

    Survival curve data for oxygenated E. coli AB2480 irradiated with 6 MVp photons in the absence and presence of DNA are presented for bacteria which have or have not received photoreactivation treatment following x-ray exposure. At the concentration of DNA used (OD = 4.4 at 260 nm) partial protection against induction of photoreactivatable damage was attained. Following photoreactivation the survival curves had the same slope, irrespective of the presence or absence of DNA. Survival data for oxygenated E.coli AB2480 irradiated with 50 Gy of 6 MVp photons in the presence of DNA at varying concentrations (OD range 0.5 to 12) and then processed with or without exposure to photoreactivating light are also presented. Survival increased with DNA concentration in the absence, but not in the presence, of photoreactivation. It is concluded that theoretical considerations and experimental data are consistent with Cerenkov light being responsible for the production of a major part of the photoreactivatable damage induced in E.coli DNA by high energy X-,γ- or electron irradiation, but that the data obtained with low energy X-rays (300 kVp) and with high energy X-rays (6 MVp) plus DNA as a 'scavenger' of Cerenkov light, are indicative of a component of the photoreactivatable damage being induced by a mechanism not involving Cerenkov light. (U.K.)

  17. Cerenkov light and the production of photoreactivatable damage in X-irradiated E. coli

    Energy Technology Data Exchange (ETDEWEB)

    Redpath, J L; Zabilansky, E; Morgan, T [California Univ., Irvine (USA). Dept. of Radiological Sciences; Ward, J F [California Univ., San Diego, La Jolla (USA). Dept. of Radiology

    1981-05-01

    Survival curve data for oxygenated E. coli AB2480 irradiated with 6 MVp photons in the absence and presence of DNA are presented for bacteria which have or have not received photoreactivation treatment following x-ray exposure. At the concentration of DNA used (OD = 4.4 at 260 nm) partial protection against induction of photoreactivatable damage was attained. Following photoreactivation the survival curves had the same slope, irrespective of the presence or absence of DNA. Survival data for oxygenated E.coli AB2480 irradiated with 50 Gy of 6 MVp photons in the presence of DNA at varying concentrations (OD range 0.5 to 12) and then processed with or without exposure to photoreactivating light are also presented. Survival increased with DNA concentration in the absence, but not in the presence, of photoreactivation. It is concluded that theoretical considerations and experimental data are consistent with Cerenkov light being responsible for the production of a major part of the photoreactivatable damage induced in E. coli DNA by high energy X-, ..gamma..- or electron irradiation, but that the data obtained with low energy X-rays (300 kVp) and with high energy X-rays (6 MVp) plus DNA as a scavenger of Cerenkov light, are indicative of a component of the photoreactivatable damage being induced by a mechanism not involving Cerenkov light.

  18. Radiation damage structure in irradiated and annealed 440 WWER-Type reactor pressure vessel steels

    International Nuclear Information System (INIS)

    Kocik, J.; Keilova, E.

    1993-01-01

    A review of irradiation damages in WWER-type RPV steels based on conventional Transmission Electron Microscopy investigations in a power reactor and a research reactor, is presented; the samples consist in Cr-Mo-V ferritic steel (15Kh2MFA type). The visible part of radiation-induced defects consists of very fine vanadium carbide precipitates, small dislocation loops and black dots (presumably corresponding to clusters and particle embryos formed from vacancies and solute-atoms (vanadium, copper, phosphorus) and carbon associated with vanadium. Radiation-induced defects are concentrated at dislocation substructure during irradiation in a power reactor, revealing the role of radiation-enhanced diffusion in damage structure forming process. Contrarily, the distribution of defects resulting from annealing of specimens irradiated in the research reactor is pre-determined by an homogenous distribution of radiation-induced defects prior to annealing. Increasing the number of re-irradiation and annealing cycles, the amount of dislocation loops among all defects seems to be growing. Simultaneously, the dislocation substructure recovers considerably. (authors). 14 refs., 11 figs., 3 tabs

  19. Radiation damage structure in irradiated and annealed 440 WWER-Type reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Kocik, J; Keilova, E [Czech Nuclear Society, Prague (Czech Republic)

    1994-12-31

    A review of irradiation damages in WWER-type RPV steels based on conventional Transmission Electron Microscopy investigations in a power reactor and a research reactor, is presented; the samples consist in Cr-Mo-V ferritic steel (15Kh2MFA type). The visible part of radiation-induced defects consists of very fine vanadium carbide precipitates, small dislocation loops and black dots (presumably corresponding) to clusters and particle embryos formed from vacancies and solute-atoms (vanadium, copper, phosphorus) and carbon associated with vanadium. Radiation-induced defects are concentrated at dislocation substructure during irradiation in a power reactor, revealing the role of radiation-enhanced diffusion in damage structure forming process. Contrarily, the distribution of defects resulting from annealing of specimens irradiated in the research reactor is pre-determined by an homogenous distribution of radiation-induced defects prior to annealing. Increasing the number of re-irradiation and annealing cycles, the amount of dislocation loops among all defects seems to be growing. Simultaneously, the dislocation substructure recovers considerably. (authors). 14 refs., 11 figs., 3 tabs.

  20. High-flux He+ irradiation effects on surface damages of tungsten under ITER relevant conditions

    International Nuclear Information System (INIS)

    Liu, Lu; Liu, Dongping; Hong, Yi; Fan, Hongyu; Ni, Weiyuan; Yang, Qi; Bi, Zhenhua; Benstetter, Günther; Li, Shouzhe

    2016-01-01

    A large-power inductively coupled plasma source was designed to perform the continuous helium ions (He + ) irradiations of polycrystalline tungsten (W) under International Thermonuclear Experimental Reactor (ITER) relevant conditions. He + irradiations were performed at He + fluxes of 2.3 × 10 21 –1.6 × 10 22 /m 2  s and He + energies of 12–220 eV. Surface damages and microstructures of irradiated W were observed by scanning electron microscopy. This study showed the growth of nano-fuzzes with their lengths of 1.3–2.0 μm at He + energies of >70 eV or He + fluxes of >1.3 × 10 22 /m 2  s. Nanometer-sized defects or columnar microstructures were formed in W surface layer due to low-energy He + irradiations at an elevated temperature (>1300 K). The diffusion and coalescence of He atoms in W surface layers led to the growth and structures of nano-fuzzes. This study indicated that a reduction of He + energy below 12–30 eV may greatly decrease the surface damage of tungsten diverter in the fusion reactor.

  1. 90Y/90 Sr electron induced damages in an essential eucalyptus oil related to the absorbed dose

    International Nuclear Information System (INIS)

    Heredia Cardona, J.A.; Diaz Rizo, O.; Martinez Luzardo, F.; Quert, R.

    2007-01-01

    A good irradiation geometry was achieved in order to carry out the irradiation of an essential eucalyptus oil with a 90 Y/ 90 Sr electron source. The Monte Carlo simulation code MCNP-4C was employed to determine the absorbed doses in this particular experimental configuration. It also helped us to understand which electrons (from an energetic point of view) were responsible for the damages. In order to identify the induced damages, the irradiated samples were studied by mass spectrometry. The obtained results were related to the absorbed doses determined by the computational simulation

  2. Electron-beam damaged high-temperature superconductor Josephson junctions

    International Nuclear Information System (INIS)

    Pauza, A.J.; Booij, W.E.; Herrmann, K.; Moore, D.F.; Blamire, M.G.; Rudman, D.A.; Vale, L.R.

    1997-01-01

    Results are presented on the fabrication and characterization of high critical temperature Josephson junctions in thin films of YBa 2 Cu 3 O 7-δ produced by the process of focused electron-beam irradiation using 350 keV electrons. The junctions so produced have uniform spatial current densities, can be described in terms of the resistive shunted junction model, and their current densities can be tailored for a given operating temperature. The physical properties of the damaged barrier can be described as a superconducting material of either reduced or zero critical temperature (T c ), which has a length of ∼15nm. The T c reduction is caused primarily by oxygen Frenkel defects in the Cu - O planes. The large beam currents used in the fabrication of the junctions mean that the extent of the barrier is limited by the incident electron-beam diameter, rather than by scattering within the film. The properties of the barrier can be calculated using a superconductor/normal/superconductor (SNS) junction model with no boundary resistance. From the SNS model, we can predict the scaling of the critical current resistance (I c R n ) product and gain insight into the factors controlling the junction properties, T c , and reproducibility. From the measured I c R n scaling data, we can predict the I c R n product of a junction at a given operating temperature with a given current density. I c R n products of ∼2mV can be achieved at 4.2 K. The reproducibility of several junctions in a number of samples can be characterized by the ratio of the maximum-to-minimum critical currents on the same substrate of less than 1.4. Stability over several months has been demonstrated at room and refrigerator temperatures (297 and 281 K) for junctions that have been initially over damaged and then annealed at temperatures ∼380K. (Abstract Truncated)

  3. Corrosion of electron-irradiated Zr-2.5Nb and Zircaloy-2

    Energy Technology Data Exchange (ETDEWEB)

    Woo, O.-T.; McDougall, G.M.; Hutcheon, R.M.; Urbanic, V.F.; Griffiths, M.; Coleman, C.E

    2000-07-01

    We used 10-MeV electrons to rapidly produce radiation damage in zirconium alloys, investigated whether electrons produced the same microstructural changes as neutrons, then performed post-irradiation corrosion tests to determine whether electron-irradiated materials displayed similar corrosion behavior to neutron-irradiated materials. Two irradiations were completed using 10-MeV electrons with the beam normal to thin disks of material of 4 diameter slightly larger than the beam. The beam distribution. and disk cooling were designed to produce radial temperature and dose distributions having maxima at the disk center. A high-temperature irradiation was performed on annealed Zr-2.5Nb disks, achieving a central dose of 1.3 dpa and at a central temperature of {approx}450 deg C. After irradiation, the samples contained needle-like {beta}-Nb precipitates in the {alpha}-Zr matrix similar to those produced by neutrons. A low-temperature irradiation was performed on half-moon disks of Zr-2.5Nb and Zircaloy-2 pressure tube materials at 310 deg C central temperature and 1.3-dpa central dose. Dislocation loops were observed, again similar to those produced in neutron-irradiated materials. Some of the high-temperature electron-irradiated disks were exposed to 300 deg C moist air (saturated with D{sub 2}O), and in separate tests, high- and low-temperature irradiated disks were corroded in 300 deg C D{sub 2}0 (11.0 pD at room temperature) in an autoclave. Measurements of oxide thickness by Fourier Transform Infrared Reflectance (FTIR) spectroscopy showed that electron irradiation reduced the corrosion rate of Zr-2.5Nb compared with that of unirradiated material, as observed for neutron irradiation. For exposures to moist air and to D{sub 2}O, the theoretical deuterium uptakes for the electron-irradiated materials were, respectively, about 4 times and 1.5 to 2 times those for the unirradiated materials. This is also in good agreement with results for neutron-irradiated pressure

  4. Corrosion of electron-irradiated Zr-2.5Nb and Zircaloy-2

    International Nuclear Information System (INIS)

    Woo, O.-T.; McDougall, G.M.; Hutcheon, R.M.; Urbanic, V.F.; Griffiths, M.; Coleman, C.E.

    2000-01-01

    We used 10-MeV electrons to rapidly produce radiation damage in zirconium alloys, investigated whether electrons produced the same microstructural changes as neutrons, then performed post-irradiation corrosion tests to determine whether electron-irradiated materials displayed similar corrosion behavior to neutron-irradiated materials. Two irradiations were completed using 10-MeV electrons with the beam normal to thin disks of material of 4 diameter slightly larger than the beam. The beam distribution. and disk cooling were designed to produce radial temperature and dose distributions having maxima at the disk center. A high-temperature irradiation was performed on annealed Zr-2.5Nb disks, achieving a central dose of 1.3 dpa and at a central temperature of ∼450 deg C. After irradiation, the samples contained needle-like β-Nb precipitates in the α-Zr matrix similar to those produced by neutrons. A low-temperature irradiation was performed on half-moon disks of Zr-2.5Nb and Zircaloy-2 pressure tube materials at 310 deg C central temperature and 1.3-dpa central dose. Dislocation loops were observed, again similar to those produced in neutron-irradiated materials. Some of the high-temperature electron-irradiated disks were exposed to 300 deg C moist air (saturated with D 2 O), and in separate tests, high- and low-temperature irradiated disks were corroded in 300 deg C D 2 0 (11.0 pD at room temperature) in an autoclave. Measurements of oxide thickness by Fourier Transform Infrared Reflectance (FTIR) spectroscopy showed that electron irradiation reduced the corrosion rate of Zr-2.5Nb compared with that of unirradiated material, as observed for neutron irradiation. For exposures to moist air and to D 2 O, the theoretical deuterium uptakes for the electron-irradiated materials were, respectively, about 4 times and 1.5 to 2 times those for the unirradiated materials. This is also in good agreement with results for neutron-irradiated pressure tube materials. Thus, 10-Me

  5. First results from electron-photon damage equivalence studies on a generic ethylene-propylene rubber

    International Nuclear Information System (INIS)

    Buckalew, W.H.

    1986-04-01

    As part of a simulator adequacy assessment program, the relative effectiveness of electrons and photons to produce damage in a generic ethylene propylene rubber (EPR) has been investigated. The investigation was limited in extent in that a single EPR material, in three thickness, was exposed to Cobalt-60 photons and three electron beam energies. Basing material damage on changes in the EPR mechanical properties elongation and tensile strength, we observed that EPR damage was a smoothly varying function of absorbed energy and independent of irradiating particle type. EPR damage tracked equally well as a function of both incident particle energy and material front surface dose. Based on these preliminary data, we tentatively concluded that a correlation between particle, particle energy, and material damage (as measured by changes in material elongation and/or tensile strength) has been demonstrated. 14 figs

  6. Surface damage in the small intestine of the mouse after X - or neutron irradiation

    International Nuclear Information System (INIS)

    Hamlet, R.; Carr, K.E.; Nias, A.H.; Watt, C.

    1981-01-01

    Damage after X-irradiation includes lateral villous collapse, progressing after 3 - 5 days to villi which sometimes show signs of vertical collapse. After neutron irradiation vertical villous collapse is established earlier, with less swelling of villous tips. It seems, therefore, that at radiobiologically equivalent doses, neutron and X-irradiation produce different levels of surface damage, with neutron irradiation being the more destructive. Early villous tip damage may perhaps be due to disruption of susceptible cells already at the extrusion zone, or to stromal damage

  7. Quantitative Analysis of Electron Beam Damage in Organic Thin Films

    OpenAIRE

    Leijten, Zino J. W. A.; Keizer, Arthur D. A.; de With, Gijsbertus; Friedrich, Heiner

    2017-01-01

    In transmission electron microscopy (TEM) the interaction of an electron beam with polymers such as P3HT:PCBM photovoltaic nanocomposites results in electron beam damage, which is the most important factor limiting acquisition of structural or chemical data at high spatial resolution. Beam effects can vary depending on parameters such as electron dose rate, temperature during imaging, and the presence of water and oxygen in the sample. Furthermore, beam damage will occur at different length s...

  8. Repair of sublethal damage in mammalian cells irradiated at ultrahigh dose rates

    International Nuclear Information System (INIS)

    Gerweck, L.E.; Epp, E.R.; Michaels, H.B.; Ling, C.C.; Peterson, E.C.

    1979-01-01

    The lethal response of asynchronous Chinese hamster ovary (CHO) cells exposed to single and split doses of radiation at conventional or ultrahigh dose rates has been examined to determine whether repair of sublethal damage occurs in cells irradiated at ultrahigh dose rates. The high-intensity irradiations were performed with electrons delivered in single 3-nsec pulses from a 600-kV field emission source under medium-removed, thin-layer conditions. Conventional dose-rate experiments were done under identical thin-layer conditions with 50-kVp x rays, or under full-medium conditions with 280-kVp x rays. Oxygenated cells were irradiated and maintained at 22 to 24 0 C between exposures. Survival did not increase as the time between two doses of pulsed electrons increased from 0 to 4 min, indicating no evidence of fast repair. However, increased survival was observed when 30 to 90 min was allowed to elapse between the split doses. The half-time for maximum repair was approx. = 30 min irrespective of the exposure conditions and radiation modality used. Observed repair ratios increased from approx. = 2 to 4 as the single-dose surviving fraction decreased from 10 -2 to 5 x 10 -4 . Over this survival range the repair ratios, measured at the same value of surviving fraction, were independent of dose rate. The observed repair ratios imply that the shoulder regions of the nonfractionated x-ray and pulsed-electron survival curves were not completely restored between the split doses. However, the fraction of the shoulder restored between split doses of radiation was dose-rate-independent. It is concluded that sublethal damage can be repaired in oxygenated CHO cells irradiated at dose rates of the order of 10 11 rad/sec

  9. Radiation effects and damage formation in semiconductors due to high-energy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kamarou, A.

    2006-11-07

    The object of this thesis was the study of ion-beam induced damage formation and annealing in crystalline and conventionally predamaged Ge, GaAs, and InP. The samples were irradiated either at {approx}80 K or at room temperature with Kr, Xe, or Au ions with specific energy of about 0.3 MeV/u to 3 MeV/u. Thereafter the samples were studied by means of Rutherford backscattering spectroscopy and/or transmission electron microscopy.

  10. Radiation effects and damage formation in semiconductors due to high-energy ion irradiation

    International Nuclear Information System (INIS)

    Kamarou, A.

    2006-01-01

    The object of this thesis was the study of ion-beam induced damage formation and annealing in crystalline and conventionally predamaged Ge, GaAs, and InP. The samples were irradiated either at ∼80 K or at room temperature with Kr, Xe, or Au ions with specific energy of about 0.3 MeV/u to 3 MeV/u. Thereafter the samples were studied by means of Rutherford backscattering spectroscopy and/or transmission electron microscopy

  11. Damage under irradiation of lithium aluminate γ-LiAlO2

    International Nuclear Information System (INIS)

    Auvray-Gely, M.H.

    1987-11-01

    Electron paramagnetic resonance and optical absorption have been used to detect the point defects created by different irradiations (electrons, He + ions, protons, X and gamma photons), transmission electron microscopy has been used to analyse samples before irradiation and observe the extended defects produced by irradiation. Defect nature is also discussed [fr

  12. Radiation damage of silicon structures with electrons of 900 MeV

    CERN Document Server

    Rachevskaia, I; Bosisio, L; Dittongo, S; Quai, E; Rizzo, G

    2002-01-01

    We present first results on the irradiation of double-sided silicon microstrip detectors and test structures performed at the Elettra synchrotron radiation facility at Trieste, Italy. The devices were irradiated with 900 MeV electrons. The test structures we used for studying bulk, surface and oxide irradiation damage were guard ring diodes, gated diodes and MOS capacitors. The test structures and the double-sided microstrip detectors were produced by Micron Semiconductor Ltd. (England) and IRST (Trento, Italy). For the first time, bulk-type inversion is observed to occur after high-energy electron irradiation. Current and inter-strip resistance measurements performed on the microstrip detectors show that the devices are still usable after type inversion.

  13. Electromagnetic Dissociation and Spacecraft Electronics Damage

    Science.gov (United States)

    Norbury, John W.

    2016-01-01

    When protons or heavy ions from galactic cosmic rays (GCR) or solar particle events (SPE) interact with target nuclei in spacecraft, there can be two different types of interactions. The more familiar strong nuclear interaction often dominates and is responsible for nuclear fragmentation in either the GCR or SPE projectile nucleus or the spacecraft target nucleus. (Of course, the proton does not break up, except possibly to produce pions or other hadrons.) The less familiar, second type of interaction is due to the very strong electromagnetic fields that exist when two charged nuclei pass very close to each other. This process is called electromagnetic dissociation (EMD) and primarily results in the emission of neutrons, protons and light ions (isotopes of hydrogen and helium). The cross section for particle production is approximately defined as the number of particles produced in nucleus-nucleus collisions or other types of reactions. (There are various kinematic and other factors which multiply the particle number to arrive at the cross section.) Strong, nuclear interactions usually dominate the nuclear reactions of most interest that occur between GCR and target nuclei. However, for heavy nuclei (near Fe and beyond) at high energy the EMD cross section can be much larger than the strong nuclear interaction cross section. This paper poses a question: Are there projectile or target nuclei combinations in the interaction of GCR or SPE where the EMD reaction cross section plays a dominant role? If the answer is affirmative, then EMD mechanisms should be an integral part of codes that are used to predict damage to spacecraft electronics. The question can become more fine-tuned and one can ask about total reaction cross sections as compared to double differential cross sections. These issues will be addressed in the present paper.

  14. Photoreactivation of ultraviolet-irradiation damage in Staphylococcus aureus

    International Nuclear Information System (INIS)

    Adkins, B. Jr.; Allen, W.E.

    1982-01-01

    This study reports the capacity of Staphylococcus aureus strain 7 - 8 to undergo photoenzymatic repair of UV-irradiation induced damage and compares it to the photoreactivation (PR) response of Escherichia coli strain B. Staphylococcus aureaus showed greater inhibition by UV irradiation than E. coli, consistent with its higher adenine and thymine content of DNA. Staphylococcus aureus showed an enhanced rate of photoreactivation with no lag in initiation of the PR response at low PR doses compared to E. coli. Maximum PR capacity of both cultures was about equal and occurred in cultures incubated at 23 - 25 0 . The PR responses at 11 - 12 and 35 - 37 0 for S. aureus and E. coli differed although both were capable of PR at each of these temperatures. The PR response of E. coli was directly related to the dosage of PR light (J/m 2 ); however, the photoenzymatic capacity of S. aureus was not directly responsive to continued decrease in light intensity. The capacity of S. aureus to undergo liquid holding recovery (LHR) occurred at 23 - 25 0 (not at 11 - 12 0 or 35 - 37 0 ), whereas E. coli underwent LHR at 11 - 12 0 and 23 - 25 0 but not at 35 - 37 0 . The LHR response of S. aureus was somewhat more effective than E. coli and did not show the direct response to increased liquid-holding period as did E. coli. (author)

  15. Study of damages by neutron irradiation in lithium aluminates; Estudio de danos por irradiacion neutronica en aluminatos de litio

    Energy Technology Data Exchange (ETDEWEB)

    Palacios G, O

    1999-06-01

    Lithium aluminates proposed to the production of tritium in fusion nuclear reactors, due to the thermal stability that they present as well as the behavior of the aluminium to the irradiation. As a neutron flux with profile ({approx_equal} 14 Mev) of a fusion reactor is not available. A irradiation experiment was designed in order to know the micro and nano structure damages produced by fast and thermal neutrons in two irradiation positions of the fusion nuclear reactor Triga Mark III: CT (Thermal Column) and SIFCA (System of Irradiation Fixed of Capsules). In this work samples of lithium aluminate were characterized by XRD (X-Ray Diffraction), TEM (Transmission Electron Microscopy) and SEM (Scanning Electron Microscopy). Two samples were prepared by two methods: a) coalition method and b) peroxide method. This characterization comprised original and irradiated samples. The irradiated sample amounted to 4 in total: one for each preparation method and one for each irradiation position. The object of this analysis was to correlate with the received neutron dose the damages suffered by the samples with the neutron irradiation during long periods (440 H), in their micro and nano structure aspects; in order to understand the changes as a function of the irradiation zone (with thermal and fast neutron flux) and the preparation methods of the samples and having as an antecedent the irradiation in SIFCA position by short times (2h). The obtained results are referred to the stability of {gamma} -aluminate phase, under given conditions of irradiation and defined nano structure arrangement. They also refer to the proposals of growth mechanism and nucleation of new phases. The error associated with the measurement of neutron dose is also discussed. (Author)

  16. A comparative study on the effects of electron beam irradiation on imidacloprid-resistant and -susceptible Aphis gossypii (Hemiptera: Aphididae)

    International Nuclear Information System (INIS)

    Yun, Seung-Hwan; Koo, Hyun-Na; Lee, Seon-Woo; Kim, Hyun Kyung; Kim, Yuri; Han, Bumsoo; Kim, Gil-Hah

    2015-01-01

    The melon and cotton aphid, Aphis gossypii, is a polyphagous insect pest. This study compared the development, reproduction, DNA damage, recovery, and gene expression in imidacloprid-resistant (IMI-R) and -susceptible (S) strains of A. gossypii by electron beam irradiation. When 1st instar nymphs were irradiated with 100 Gy, the fecundity (nymphs of F 1 generation) of the resultant adults were completely inhibited. When adults were irradiated with 200 Gy, the number of total 1st instar nymphs produced per adult was 3.0±1.7 and 1.9±1.4 in the S and IMI-R strains, respectively, but adult development was completely suppressed. However, electron beam irradiation did not affect adult longevity in either the S or IMI-R strain. There was no statistically significant difference between the effect of irradiation on the S and IMI-R strains. Therefore, electron beam irradiation at 200 Gy could be used as a phytosanitary irradiation treatment for both S and IMI-R strains of A. gossypii. The DNA damage caused by electron beam irradiation was evaluated by an alkaline comet assay. Exposure to an electron beam (50 Gy) induced DNA damage that was repaired to a similar level as the untreated control group (0 Gy) over time. However, at more than 100 Gy, the DNA damage was not completely repaired. The expression of P450, HSP70, cuticle protein, and elongation factor genes were higher in the IMI-R strain than in the S strain. - Highlights: • Electron beam irradiation induces abnormal development in both the IMI-R and -S strain. • Electron beam irradiation induces DNA damage in both the S and IMI-R strain. • The expression of several specific genes were higher in the IMI-R strain. • 200 Gy could be used as a phytosanitary treatment for both strains of this species

  17. Application of electron beam irradiation. 4. Treatment of pollutants by electron beam irradiation

    International Nuclear Information System (INIS)

    Tokunaga, Okihiro; Arai, Hidehiko

    1994-01-01

    Electron beam irradiation is capable of dissolving and removing pollutants, such as sulfur oxides, nitrogen oxides, and organic compounds, by easy production of OH radicals in flue gas and water. This paper deals with current status in the search for techniques for treating flue gas and waste water, using electron beam irradiation. Pilot tests have been conducted during the period 1991-1994 for the treatment of flue gas caused by coal and garbage burning and road tunnels. Firstly, techniques for cleaning flue gas with electron beams are outlined, with special reference to their characteristics and process of research development. Secondly, the application of electron beam irradiation in the treatment of waste water is described in terms of the following: (1) disinfection of sewage, (2) cleaning of water polluted with toxic organic compounds, (3) treatment for eliminating sewage sludge, (4) promotion of sewage sludge sedimentation, (5) disinfection and composting of sewage sludge, and (6) regeneration of activated carbon used for the treatment of waste water. (N.K.)

  18. Photoreactivity in Saccharomyces cerevisiae cells after irradiation with 25 MeV electrons

    International Nuclear Information System (INIS)

    Tsyb, T.S.; Seleva, N.G.; Myasnik, M.N.; Kabakova, N.M.

    1986-01-01

    Significant photoreactivation was noted in radio- and UV-sensitive rad-mutants of Saccharomyces cerevisiae cells exposed to 25 MeV electrons. In order to make the photoreactivable damage be manifest anoxic conditions of irradiation should be chosen as optimal ones. It was shown that the low oxygen effect was partially associated with the photoreactivable damage involved in the lethal effect of ionizing radiation

  19. In-situ observations of point-defect precipitation at dislocations in electron-irradiated silver

    International Nuclear Information System (INIS)

    Jenkins, M.L.; Hardy, G.J.; Kirk, M.A.

    1986-09-01

    In-situ weak-beam observations of the development of electron irradiation damage at dislocations in silver are described. Dislocations constrict and promote in their vicinity the formation of stacking-fault tetrahedra. The possibility that these are of interstitial nature is discussed

  20. Irradiation test of the HCAL Forward and Endcap upgrade electronics at the CHARM facility at CERN

    CERN Document Server

    AUTHOR|(CDS)2068434; Costanza, Francesco; Karakaya, Tugba; Sahin, Mehmet Ozgur; Lincoln, Don; Strobbe, Nadja; Kaminskiy, Alexander; Tlisov, Danila; Wang, Yanchu; Hirschauer, James Francis

    2016-01-01

    In the period October 21 – 28, 2015, the CMS HCAL group did a radiation tolerance study for the Phase I Upgrade HF, HE and HB front end electronics. The test was conducted at the CERN CHARM facility, which is a mixed field radiation facility. No permanent damages were observed. Effects observed during the irradiation are presented.

  1. The electron irradiation effects in different structures of diodes

    International Nuclear Information System (INIS)

    Li Quanfen; Wang Jiaxu

    1993-01-01

    This paper describes the different electron irradiation effects in different structures of diodes and the different results produced by different irradiation ways. From this work, we can know how to choose proper manufacture arts and comprehensive factors according to the structures of diodes and the irradiation conditions

  2. Sprout inhibition of potatoes by electron irradiation, (2)

    International Nuclear Information System (INIS)

    Furuta, Junichiro; Hiraoka, Eiichi; Okamoto, Shinichi; Fujishiro, Masatoshi; Kanazawa, Tamotsu; Ohnishi, Tokuhiro; Tsujii, Yukio; Hori, Shiro

    1982-01-01

    Sprouting of potatoes are inhibited usually by the gamma-ray irradiation. The buds of potatoes exist in a very thin layer near surface of each tuber. So the inhibition will be performed sufficiently by surface irradiation using electron beams. To irradiate all surfaces of each potato uniformly, the authors prepare a new apparatus which is a conveyer passing under an electron beam scanner of accelerator rotating the potatoes by many rotating rollers. The sprout inhibition experiment of potatoes was performed by following three methods to obtain the performance of this apparatus, and the results were compared. 1) turn over irradiation method --- potatoes were arranged in one layer in plastic baskets and were irradiated on the conveyor. After irradiation, the potatoes were turned over and were irradiated again. 2) rotating irradiation method --- potatoes were rotated on the rotating roller apparatus set on the conveyer and were passed under the electron beam scanner. 3) rotating irradiation method with an improved rotating roller apparatus --- the rotating rollers have many protuberances on their surface to irradiate all of potato surface more uniform. 550 keV electron beams by Cockcroft-Walton type accelerator were used for the irradiation and the irradiated dose was 5 to 20 krad. 40 pieces of potates, ''Danshaku'' variety yielded in June 1981, were irradiated for each dose in the beginning of August. Prior to these irradiation experiments, the dose and dose uniformity were checked by the agar color dosimeters. After the irradiation, potatoes were stored in natural condition and their sprouting was observed. The potatoes irradiated by the improved rotating roller apparatus were almost completely sprout-inhibited by 20 krad irradiation. (author)

  3. Radiation-damage studies, irradiations and high-dose dosimetry for LHC detectors

    CERN Document Server

    Coninckx, F; León-Florián, E; Leutz, H; Schönbacher, Helmut; Sonderegger, P; Tavlet, Marc; Sopko, B; Henschel, H; Schmidt, H U; Boden, A; Bräunig, D; Wulf, F; Cramariuc, R; Ilie, D; Fattibene, P; Onori, S; Miljanic, S; Paic, G; Razen, B; Razem, D; Rendic, D; CERN. Geneva. Detector Research and Development Committee

    1991-01-01

    The proposal is divided into a main project and special projects. The main project consists of a service similar to the one given in the past to accelerator construction projects at CERN (ISR,SPS,LEP) on high-dose dosimetry, material irradiations, irradiations tests, standardization of test procedures and data compilations. Large experience in this field and numerous radiation damage test data of insulating and structural materials are available. The special projects cover three topics which are of specific interest for LHC detector physicists and engineers at CERN and in other high energy physics institutes, namely: Radiation effects in scintillators; Selection of radiation hard optical fibres for data transmission; and Selection and testing of radiation hard electronic components.

  4. An investigation of the electron irradiation of graphite in a helium atmosphere using a modified electron microscope

    International Nuclear Information System (INIS)

    Burden, A.P.; Hutchison, J.L.

    1997-01-01

    The behaviour of graphite particles immersed in helium gas and irradiated with an electron-beam has been investigated. Because this treatment was performed in a modified high resolution transmission electron microscope, the rapid morphological and microstructural changes that occurred could be directly observed. The results have implications for future controlled environment microscopy of carbonaceous materials and the characterisation of such microscopes. It is also shown that the processes can provide insight into ion-irradiation induced damage of graphite and the mechanism of fullerene generation. (Author)

  5. A study of the effect of helium concentration and displacement damage on the microstructure of helium ion irradiated tungsten

    Science.gov (United States)

    Harrison, R. W.; Greaves, G.; Hinks, J. A.; Donnelly, S. E.

    2017-11-01

    Transmission electron microscopy (TEM) with in-situ He ion irradiation has been used to examine the damage microstructure of W when varying the helium concentration to displacement damage ratio, irradiation temperature and total dose. Irradiations employed 15, 60 or 85 keV He ions, at temperatures between 500 and 1000 °C up to doses of ∼3.0 DPA. Once nucleated and grown to an observable size in the TEM, bubble diameter as a function of irradiation dose did not measurably increase at irradiation temperatures of 500 °C between 1.0 and 3.0 DPA; this is attributed to the low mobility of vacancies and He/vacancy complexes at these temperatures. Bubble diameter increased slightly for irradiation temperatures of 750 °C and rapidly increased when irradiated at 1000 °C. Dislocation loops were observed at irradiation temperatures of 500 and 750 °C and no loops were observed at 1000 °C. Burgers vectors of the dislocations were determined to be b = ±½ type only and both vacancy and interstitial loops were observed. The proportion of interstitial loops increased with He-appm/DPA ratio and this is attributed to the concomitant increase in bubble areal density, which reduces the vacancy flux for both the growth of vacancy-type loops and the annihilation of interstitial clusters.

  6. Monte Carlo study of electron irradiation effect on YBCO dpa profiles

    International Nuclear Information System (INIS)

    Pinnera, I.; Cruz, C.; Abreu, Y.; Leyva, A.; Van Espen, P.

    2011-01-01

    The Monte Carlo assisted Classical Method (MCCM) consists on a calculation procedure for determining the displacements per atom (dpa) distribution in solid materials. This algorithm allows studying the gamma and electron irradiation damage in different materials. It is based on the electrons elastic scattering classic theories and the use of Monte Carlo simulation for the physical processes involved. The present study deals with the Monte Carlo simulation of electron irradiation effects on YBa 2 Cu 3 O 7-x (YBCO) slabs using the MCNPX code system. Displacements per atom distributions are obtained through the MCCM for electron irradiation up to 10 MeV. In-depth dpa profiles for electrons and positrons are obtained and analyzed. Also, for each atomic species in the material, the dpa distributions are calculated. All the results are discussed in the present contribution. (Author)

  7. Characterization of damaging in apatitic materials irradiated with heavy ions and thermally annealed

    International Nuclear Information System (INIS)

    Tisserand, R.

    2004-12-01

    Some minerals belonging to the family of apatite are seen to be potential candidates for use as conditioning matrices or transmutation targets for high level nuclear waste management. Indeed, studies of natural nuclear reactors (Oklo) highlighted the strong ability of these minerals to anneal irradiation damage. In order to determine the global behaviour of these materials, we performed a fundamental study on the evolution of irradiation damage induced by various heavy ions in two apatites: a natural phospho-calcic fluor-apatite from Durango and a synthetic sintered mono-silicated fluor-apatite, called britholite. The damage in these materials was measured by using channelling R.B.S. and X-ray diffraction respectively and by determining an amorphization effective radius Re. The results revealed a similar behaviour for both apatites according to the electronic energy deposit at the entrance of the material. In addition, the effect of an isothermal annealing at 300 C was quantified on a mono-silicated britholite previously irradiated with Kr ions. We highlighted in this case the return of the lattice parameters to their initial values, followed by a partial and slow rebuilding of the crystalline lattice versus the annealing time. Finally, we followed the changes in the morphology of etch pits in the Durango fluor-apatite after acid dissolution as a function of the energy deposit by the ions. We showed that the influence of crystallography leads quickly to opening angles close to 30 degrees. The calculation of etching velocities within the irradiated material highlighted that there is a range of deposit energy where the velocity ratio increases strongly before becoming constant. (author)

  8. Design of electron detection system for pulse electron irradiator

    International Nuclear Information System (INIS)

    Anjar Anggraini H; Agus Purwadi; Lely Susita RM; Bambang Siswanto; Agus Wijayanto

    2016-01-01

    Design of electron detection system for pulse electron irradiator has been conducted on the Plasma Cathode Electron Source by Rogowski coil technique. Rogowski coil has ability to capture the induced magnetic field of the electric current, subsequent induced magnetic field will provide voltage after passing integrator. This diagnostic used combination of copper wire, ferrite and RC integrator. The design depends on the pulse width and the value of plasma current that passes through the coil, thus the number of windings, coil area and integrator can be designed. For plasma spots current of IDPS expected to be 10 A and pulse width 10 μs the Rogowski coil using MnZn ferrite with inductance L = 0.275 mH and permeability μr = 200 H/m. For the current of plasma arc ADPS expected to be 100 A and pulse width 100 μs by using inductance L=1.9634 mH and permeability μr = 6256 H/m. Electron current in extraction system expected to be 30 A and pulse width 100 μs the Rogowski coil using inductance L=51.749 mH and permeability μr= 4987 H/m. Design integrator used is the type of RC integrator. (author)

  9. Effect of low dose pre-irradiation on DNA damage and genetic material damage caused by high dosage of cyclophosphamide

    International Nuclear Information System (INIS)

    Yu Hongsheng; Zhu Jingjuan; Shang Qingjun; Wang Zhuomin; Cui Fuxian

    2007-01-01

    Objective: To study the effect of low dose γ-rays pre-irradiation on the induction of DNA damage and genetic material damage in peripheral lymphocytes by high dosage of cyclophosphamide (CTX). Methods: Male Kunming strain mice were randomly divided into five groups: control group, sham-irradiated group, low dose irradiated group(LDR group), cyclophosphamide chemotherapy group(CTX group) and low dose irradiation combined with chemotherapy group(LDR + CTX group). After being feeded for one week, all the mice were implanted subcutaneously with S180 cells in the left groin (control group excluded). On days 8 and 11, groups of LDR and LDR + CTX were administered with 75 mGy of whole-body irradiation, 30 h later groups CTX and LDR + CTX were injected intraperitoneally 3.0 mg cyclophosphamide. All the mice were sacrificed on day 13. DNA damage of the peripheral lymphocytes was analyzed using single cell gel electrophoresis (SCGE). Genetic material damage was analyzed using micronucleus frequency(MNF) of polychromatoerythrocytes(PCE) in bone marrow. Results: (1) Compared with control group and sham-irradiated group, the DNA damage of peripheral lymphocytes in CTX group were increased significantly (P 0.05). Conclusions: (1) High- dosage of CTX chemotherapy can cause DNA damage in peripheral lymphocytes. 75 mGy y-irradiation before chemotherapy may have certain protective effect on DNA damage. (2) CTX has potent mutagenic effect, giving remarkable rise to MNF of PCE. 75 mGy γ-ray pre-irradiation has not obvious protection against genetic toxicity of high-dose CTX chemotherapy. (authors)

  10. Study on radioprotection of alliin and damage mechanism in hepatocyte after irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Tae Jeong; Kim, Won Tae [Dept, of Radiological Science, Kaya University, Kimhae (Korea, Republic of)

    2016-12-15

    Liver tissue damage by a radiation exposure caused a jaundice and ascitic fluid e form harden atrophy. The reason for this lies in morphological damage of a liver cells. This study tried that observe damage mechanism of the cell organelles. It was especially observed mitochondria, endoplasmic reticulum and nuclear membrane associated with energy metabolizable. also, This study had with a radio-protector development research at the same time. Radio-protector was used to alliin that has an blood flow increase. Cell observation make used of transmission electron microscope(TEM). The result of an experiment, 7Gy of whole body irradiation was caused an inflammation in cell organelles and hypertrophy of the nucleus membrane. After 20 days, The hepatocyte has been observed in a damaged membrane on peroxisome, mitochondria and vacuole of the cell organelles. After 30 days, The hepatocyte has been observed in disconnected ribosomes on a rough endoplasmic reticulum. There was looked a giant lipoblast. There was clearly normal observed a mitochondria and nucleus membrane in the hepatocyte after alliin injection. aslo, It was no damaged the nucleus membrane. Therefore, It was identified portion a radio-protector effect from alliin.

  11. Simulation model for electron irradiated IGZO thin film transistors

    Science.gov (United States)

    Dayananda, G. K.; Shantharama Rai, C.; Jayarama, A.; Kim, Hyun Jae

    2018-02-01

    An efficient drain current simulation model for the electron irradiation effect on the electrical parameters of amorphous In-Ga-Zn-O (IGZO) thin-film transistors is developed. The model is developed based on the specifications such as gate capacitance, channel length, channel width, flat band voltage etc. Electrical parameters of un-irradiated IGZO samples were simulated and compared with the experimental parameters and 1 kGy electron irradiated parameters. The effect of electron irradiation on the IGZO sample was analysed by developing a mathematical model.

  12. Coating composition curable by electron beam irradiation

    International Nuclear Information System (INIS)

    Masuda, Hiromasa; Iijima, Ken-ichi.

    1971-01-01

    Here is provided a coating composition curable with low dose of electron beams to give a smooth coating film having no surface tackiness. In one example, 126 parts of melamine was reacted with 682 parts of formalin followed by 697 parts of β-hydroxyethyl acrylate to produce component (A) (viscosity 780 cp). On the other hand, 900 parts of tung oil was reacted with 343 parts of maleic anhydride followed by 22 parts of dimethylaminoethyl methacrylate and 406 parts of β-hydroxyethyl acrylate. The resulting product was diluted with 508 parts of methyl methacrylate to give component (B) (dark red, viscous substance). 900 parts of (A), 100 parts of (B), 0.5 part of bees wax and 0.2 part of paraffin wax were blended together. A sized material was coated with the mixture and irradiated with electron beams (6 Mrad) in the presence of air. A smooth film free from surface tackiness was obtained. β-hydroxyethyl acrylate may be replaced by other hydroxyalkyl esters of α,β-unsaturated acids, and melamine may be replaced by urea, benzoguanamine or acetoguanamine. Tung oil may be replaced by linseed, safflower, soybean, rice, oiticica or cotton seed oil. A more flexible film is obtained by using component (B) in a larger proportion. (A)/(B) ratio should be in the range of 90/10 to 10/90 by wt. (Kaichi, S.)

  13. Radiation damage relative to transmission electron microscopy of biological specimens at low temperature: a review

    International Nuclear Information System (INIS)

    Glaeser, R.M.; Taylor, K.A.

    1978-01-01

    When biological specimens are irradiated by the electron beam in the electron microscope, the specimen structure is damaged as a result of molecular excitation, ionization, and subsequent chemical reactions. The radiation damage that occurs in the normal process of electron microscopy is known to present severe limitations for imaging high resolution detail in biological specimens. The question of radiation damage at low temperatures has therefore been investigated with the view in mind of reducing somewhat the rate at which damage occurs. The radiation damage protection found for small molecule (anhydrous) organic compounds is generally rather limited or even non-existent. However, large molecule, hydrated materials show as much as a 10-fold reduction at low temperature in the rate at which radiation damage occurs, relative to the damage rate at room temperature. In the case of hydrated specimens, therefore, low temperature electron microscopy offers an important advantage as part of the overall effort required in obtaining high resolution images of complex biological structures. (author)

  14. Lattice damage assessment and optical waveguide properties in LaAlO3 single crystal irradiated with swift Si ions

    Science.gov (United States)

    Liu, Y.; Crespillo, M. L.; Huang, Q.; Wang, T. J.; Liu, P.; Wang, X. L.

    2017-02-01

    As one of the representative ABO3 perovskite-structured oxides, lanthanum aluminate (LaAlO3) crystal has emerged as one of the most valuable functional-materials, and has attracted plenty of fundamental research and promising applications in recent years. Electronic, magnetic, optical and other properties of LaAlO3 strongly depend on its crystal structure, which could be strongly modified owing to the nuclear or electronic energy loss deposited in an ion irradiation environment and, therefore, significantly affecting the performance of LaAlO3-based devices. In this work, utilizing swift (tens of MeV) Si-ion irradiation, the damage behavior of LaAlO3 crystal induced by nuclear or electronic energy loss has been studied in detail utilizing complementary characterization techniques. Differing from other perovskite-structured crystals in which the electronic energy loss could lead to the formation of an amorphous region based on the thermal spike mechanism, in this case, intense electronic energy loss in LaAlO3 will not induce any obvious structural damage. The effects of ion irradiation on the mechanical properties, including hardness increase and elastic modulus decrease, have been confirmed. On the other hand, considering the potential applications of LaAlO3 in the field of integrated optoelectronics, the optical-waveguide properties of the irradiation region have been studied. The significant correspondence (symmetrical inversion) between the iWKB-reconstructed refractive-index profile and SRIM-simulated dpa profile further proves the effects (irradiation-damage production and refractive-index decrease) of nuclear energy loss during the swift-ion penetration process in LaAlO3 crystal. In the case of the rather-thick damage layer produced by swift-ion irradiation, obtaining a damage profile will be constrained owing to the analysis-depth limitation of the characterization techniques (RBS/channeling), and our analysis process (optical guided-mode measurement and

  15. Lattice damage assessment and optical waveguide properties in LaAlO3 single crystal irradiated with swift Si ions

    International Nuclear Information System (INIS)

    Liu, Y; Wang, T J; Liu, P; Wang, X L; Crespillo, M L; Huang, Q

    2017-01-01

    As one of the representative ABO 3 perovskite-structured oxides, lanthanum aluminate (LaAlO 3 ) crystal has emerged as one of the most valuable functional-materials, and has attracted plenty of fundamental research and promising applications in recent years. Electronic, magnetic, optical and other properties of LaAlO 3 strongly depend on its crystal structure, which could be strongly modified owing to the nuclear or electronic energy loss deposited in an ion irradiation environment and, therefore, significantly affecting the performance of LaAlO 3 -based devices. In this work, utilizing swift (tens of MeV) Si-ion irradiation, the damage behavior of LaAlO 3 crystal induced by nuclear or electronic energy loss has been studied in detail utilizing complementary characterization techniques. Differing from other perovskite-structured crystals in which the electronic energy loss could lead to the formation of an amorphous region based on the thermal spike mechanism, in this case, intense electronic energy loss in LaAlO 3 will not induce any obvious structural damage. The effects of ion irradiation on the mechanical properties, including hardness increase and elastic modulus decrease, have been confirmed. On the other hand, considering the potential applications of LaAlO 3 in the field of integrated optoelectronics, the optical-waveguide properties of the irradiation region have been studied. The significant correspondence (symmetrical inversion) between the iWKB-reconstructed refractive-index profile and SRIM-simulated dpa profile further proves the effects (irradiation-damage production and refractive-index decrease) of nuclear energy loss during the swift-ion penetration process in LaAlO 3 crystal. In the case of the rather-thick damage layer produced by swift-ion irradiation, obtaining a damage profile will be constrained owing to the analysis-depth limitation of the characterization techniques (RBS/channeling), and our analysis process (optical guided

  16. Irradiation damage and recovery in shoot apices of sweet cherry (Prunus avium L.)

    International Nuclear Information System (INIS)

    Saamin, S.; Thompson, M.M.

    1990-01-01

    Full text: Dormant scions of 'Bing' were exposed to fractionated 6kR gamma rays and then grafted. Irradiated and unirradiated main buds were sampled at 3 day intervals for one month. Buds were fixed in FAA, longitudinally sectioned, and stained with hematoxylin. Both random and localised cell damage was observed in irradiated apices. There was evidence of radiosensitivity gradient in the shoot apex. Recovery from irradiation damage was via flank meristem, central meristem, or leaf primordia and axillary meristems. (author)

  17. Electron trapping during irradiation in reoxidized nitrided oxide

    International Nuclear Information System (INIS)

    Mallik, A.; Vasi, J.; Chandorkar, A.N.

    1993-01-01

    Isochronal detrapping experiments have been performed following irradiation under different gate biases in reoxidized nitrided oxide (RNO) MOS capacitors. These show electron trapping by the nitridation-induced electron traps at low oxide fields during irradiation. A difference in the detrapping behavior of trapped holes and electrons is observed, with trapped holes being detrapped at relatively lower temperatures compared to trapped electrons. Electron trapping shows a strong dependence on tile magnitude of the applied gate bias during irradiation but is independent of its polarity. Conventional oxide devices, as expected, do not show any electron trapping during irradiation by the native electron traps. Finally, a comparison of the isochronal detrapping behavior following irradiation and following avalanche injection of electrons has been made to estimate the extent of electron trapping. The results show that electron trapping by the nitridation-induced electron traps does not play the dominant role in improving radiation performance of RNO, though its contribution cannot be completely neglected for low oxide field irradiations

  18. Comparison of electron-irradiation and gamma-irradiation as a decontamination treatment of spices

    International Nuclear Information System (INIS)

    Hayashi, Toru; Todoriki, Setsuko; Mamun.

    1993-01-01

    Electron-irradiation at 10 kGy decontaminated all the eight kinds of spices (black pepper, white pepper, nutmeg, red pepper, parsley, paprika, laurel and onion powder) to the microbial levels lower than 10 2 /g. Similar sterilization effects by the irradiation were observed on heat-resistant bacterial spores. The 10 kGy irradiation did not significantly affect the contents of essential oils and colors of the spices. These results indicate that electron-irradiation at 10 kGy effectively decontaminates spices without notable adverse effect on the qualities. The disinfecting effect of electron beams on spices was smaller than that of gamma-rays. (author)

  19. Electron dosimetry in irradiation processing with rad-hard diodes

    International Nuclear Information System (INIS)

    Santos, Thais Cavalheri dos

    2012-01-01

    This work had the aim of the development of dosimetric systems based on Si special diodes, resistant to radiation damage to online monitoring of irradiation processing using 1.5 MeV electrons energy and for relative dosimetry and clinical electron beam scanning within an energy range of 6 MeV up to 21 MeV. The diodes used were produced by Float Zone standard (FZ), Magnetic Czochralski (MCz) and epitaxy growth (EPI) methods. In order to use the diodes as detectors, they were fixed on alumina base to allow the connection of the polarization electrodes and the signals extraction. After the diode assembly on the base, each one was housed in a black acrylic probe with aluminized Mylar® window and LEMO® connector. With the devices operating in photovoltaic mode, the integration of the current signals as a function of irradiation time allowed obtain the charge produced in the sensitive volume of each diode irradiated. The electron accelerator used for high doses irradiation was the DC 1500/25/4 JOB 188 of the 1.5 MeV installed at the Radiation Technology Center of the IPEN/CNEN-SP. The current profile as function of exposure time, the response repeatability, the sensitivity as function of absorbed dose and the dose response curve were studied for each device. In comparison to FZ diode, we observed a greater decrease in the sensitivity for MCz diode, and good repeatability in both cases. Also, the increasing of the charge with the absorbed dose was well fitted by a second order polynomial function. In the EPI diode characterization, this one exhibited repeatability better than CTA dosimeters applied routinely in radiation processing. The above results indicate the potential use of these radiation hardness Si diodes in online dosimetry to high doses applications. For low doses irradiation were used the linear accelerators KD2 and Primus, both manufactured by Siemens and located at Sirio-Libanes Hospital. The diodes responses were evaluated for electron beams within the

  20. Further study of the glassy low-temperature properties of irradiated crystalline quartz: neutron and electron irradiation

    International Nuclear Information System (INIS)

    Laermans, C.; Daudin, B.

    1979-01-01

    Recently it has been shown that a quartz crystal after light fast neutron irradiation shows low temperature hypersonic properties which are similar to those found in glasses although the sample was still crystalline. Additional measurements have been carried out in the neutron-irradiated sample and a sample irradiated with high energy electrons has also been investigated. (Fast neutron dose 6 x 10 18 n/cm 2 , 2 MeV electron dose 3 x 10 19 e/cm 2 ). A magnetic field up to 1.5 T was found to have no influence in the hypersonic saturation behaviour of the neutron-irradiated sample (9 GHz, 1.65 K) and thermal conductivity measurements are consistent with a number of two level systems (2 LS) an order of magnitude lower than in vitreous silica as found before. Low temperature hypersonic measurements as a function of acoustic intensity and temperature as well as thermal conductivity measurements give no evidence for the presence of 2 LS in the electron irradiated sample. Considering the damage created in both samples this indicates that 2 LS are probably not related to point defects

  1. Effect of electron beam irradiation on seed germination

    Energy Technology Data Exchange (ETDEWEB)

    Han, Seunghee; Bae, Youngmin [Changwon Univ., Changwon (Korea, Republic of)

    2013-07-01

    Effect of electron beam irradiation on seed germination was investigated in this research. Electron beam of 0.5, 1.0, 1.5 and 2.0 kGy was irradiated to the seeds of lettuce, green onion and cucumber, and the irradiated seeds were incubated at 25 .deg. Cn Nitsch medium solidified with 0.2% Phytagel. Germination percentage and the length of the sprouts were determined after 72 hours. Germination percentage of lettuce seeds was greatly reduced by the irradiation, and that of the green onion and cucumber were moderately reduced or unchanged by the irradiation. Although average length of the lettuce sprouts was reduced severely, that of the green onion and cucumber was unchanged or moderately reduced. Conclusively, electron beam irradiation might be a useful way of disinfecting some plant seeds including green onion and cucumber.

  2. Effect of electron beam irradiation on seed germination

    International Nuclear Information System (INIS)

    Han, Seunghee; Bae, Youngmin

    2013-01-01

    Effect of electron beam irradiation on seed germination was investigated in this research. Electron beam of 0.5, 1.0, 1.5 and 2.0 kGy was irradiated to the seeds of lettuce, green onion and cucumber, and the irradiated seeds were incubated at 25 .deg. Cn Nitsch medium solidified with 0.2% Phytagel. Germination percentage and the length of the sprouts were determined after 72 hours. Germination percentage of lettuce seeds was greatly reduced by the irradiation, and that of the green onion and cucumber were moderately reduced or unchanged by the irradiation. Although average length of the lettuce sprouts was reduced severely, that of the green onion and cucumber was unchanged or moderately reduced. Conclusively, electron beam irradiation might be a useful way of disinfecting some plant seeds including green onion and cucumber

  3. Damage growth in Si during self-ion irradiation: A study of ion effects over an extended energy range

    International Nuclear Information System (INIS)

    Holland, O.W.; El-Ghor, M.K.; White, C.W.

    1989-01-01

    Damage nucleation/growth in single-crystal Si during ion irradiation is discussed. For MeV ions, the rate of growth as well as the damage morphology are shown to vary widely along the track of the ion. This is attributed to a change in the dominant, defect-related reactions as the ion penetrates the crystal. The nature of these reactions were elucidated by studying the interaction of MeV ions with different types of defects. The defects were introduced into the Si crystal prior to high-energy irradiation by self-ion implantation at a medium energy (100 keV). Varied damage morphologies were produced by implanting different ion fluences. Electron microscopy and ion-channeling measurements, in conjunction with annealing studies, were used to characterize the damage. Subtle changes in the predamage morphology are shown to result in markedly different responses to the high-energy irradiation, ranging from complete annealing of the damage to rapid growth. These divergent responses occur over a narrow range of dose (2--3 times 10 14 cm -2 ) of the medium-energy ions; this range also marks a transition in the growth behavior of the damage during the predamage implantation. A model is proposed which accounts for these observations and provides insight into ion-induced growth of amorphous layers in Si and the role of the amorphous/crystalline interface in this process. 15 refs, 9 figs

  4. Radiation damage and materials performance in irradiation environment

    International Nuclear Information System (INIS)

    Singh, B.N.

    2009-01-01

    Collisions of energetic projectile particles with host atoms produce atomic displacements in the target materials. Subsequently, some of these displacements are transformed into lattice defects and survive in the form of single defects and of defect clusters. Depending on the ambient temperature, these defects and their clusters diffuse, interact, annihilate, segregate and accumulate in various forms and are responsible for the evolution of the irradiation-induced microstructure. Naturally, both physical and mechanical properties and thereby the performance and lifetime of target materials are likely to be determined by the nature and the magnitude of the accumulated defects and their spatial dispositions. The defect accumulation, microstructural evolution and the resulting materials response gets very complicated particularly under the reactor operational conditions. The complication arises from the fact that the materials used in the structural components will experience concurrently generation of defects produced by the flux of neutrons and generation of dislocations due to plastic deformation. In other words, the defect accumulation will have to be considered under the conditions of two interactive reaction kinetics operating simultaneously. Both materials and experimental variables are likely to affect the damage accumulation and thereby the materials performance. Experimental and theoretical results pertaining to effects of major materials and experimental variables on materials performance will be briefly examined. (au)

  5. Cost evaluation of irradiation system with electron accelerator

    International Nuclear Information System (INIS)

    Kashiwagi, M.

    2003-01-01

    The features of electron beam irradiation system using electron accelerator are direct energy pour into the irradiated material, no third material mixture such as catalyst, suitable for mass production and easy operation and maintenance work available. These features can bring the various applications such as cross-linking action, graft polymerization, radical polymerization and others. The selection of electron accelerator ratings is made under consideration of quality, width and thickness of irradiated material, production amount, dose required for reaction and irradiation atmosphere. Especially in a case of irradiation of wire with high insulation material such as polyethylene, the consideration of maximum thickness toward irradiation direction is necessary to avoid the discharge (Lichtenberg discharge) by charged-up electrons inside insulation material. Therefore, the acceleration voltage should be selected to make the maximum penetration larger than maximum irradiation thickness. The actual model case of estimate the irradiation cost was selected that the irradiation object was polyethylene insulated wire up to AWG no.14, irradiation amount was 5,000 km/month, necessary dose was 200 kGy, operation time was 22 d/month and 8 h/day and actual operation efficiency was considered loss time such as bobbin changing as 80%. The selected ratings of electron accelerator were acceleration voltage of 800 kV, beam current of 100 mA and irradiation width of 180 cm with irradiation pulleys stand of 60 turns x 3 lanes. The initial total cost was estimated as 3 M$(US) and operation cost was evaluated as 215 k$(US). Therefore, the irradiation cost of wire was evaluated as 0.0036 $/m. (author)

  6. Electron irradiation induced nanocrystal formation in Cu-borosilicate glass

    Energy Technology Data Exchange (ETDEWEB)

    Sabri, Mohammed Mohammed; Möbus, Günter, E-mail: g.moebus@sheffield.ac.uk [University of Sheffield, Department of Materials Science and Engineering (United Kingdom)

    2016-03-15

    Nanoscale writing of Cu nanoparticles in glasses is introduced using focused electron irradiation by transmission electron microscopy. Two types of copper borosilicate glasses, one with high and another with low Cu loading, have been tested at energies of 200–300 keV, and formation of Cu nanoparticles in a variety of shapes and sizes using different irradiation conditions is achieved. Electron energy loss spectroscopy analysis, combined with high-resolution transmission electron microscopy imaging, confirmed the irradiation-induced precipitated nanoparticles as metallic, while furnace annealing of the glass triggered dendrite-shaped particles of copper oxide. Unusual patterns of nanoparticle rings and chains under focused electron beam irradiation are also presented. Conclusively, electron beam patterning of Cu-loaded glasses is a promising alternative route to well-established femtosecond laser photoreduction of Cu ions in glass.

  7. Demonstration plant of smoke treatment by electron beam irradiation

    International Nuclear Information System (INIS)

    Kawamura, Keita

    1989-01-01

    The acid rain caused by sulfur oxides and nitrogen oxides has become the large social problem as it damages forests, lakes and agricultural crops and also buildings in Europe and America. In such circumstances, concern has been expressed in various countries on the smoke treatment technology, EBA process, which removes the sulfur oxides and nitrogen oxides contained in smoke simultaneously by irradiating electron beam on the smoke which is exhausted from power station boilers and industrial boilers and mainly causes acid rain. The research and development of this technology were begun in 1971 based on the original idea of Ebara Corp., and from 1972, those were advanced as the joint research with Japan Atomic Energy Research Institute. Thereafter, by the joint research with the technical research association on prevention of nitrogen oxides in iron and steel industry, by ammonia addition and irradiation process, the desulfurization and denitration performance was heightened, and the byproduct was successfully captured as powder, in this way, the continuous dry treatment process was established. The demonstration test plant was constructed in a coal-firing power station in Indiana, USA, and the trial operation was carried out from 1985 for two years. (K.I.)

  8. Electron beam irradiation and zeolites adsorption applied to dyeing effluents

    International Nuclear Information System (INIS)

    Higa, Marcela C.; Fungaro, Denise A.; Somessari, Elizabeth S.R.; Magdalena, Carina P.; Grosche, Lucas C.; NNeto, Antonio C.; Borrely, Sueli I.

    2007-01-01

    Wastewater generated from the textile industries contain large amount of azo dyes and many of them present low biodegradability capability. Today several countries are facing with evidences that water pollution is related to toxicity, mutagenicity and carcinogenic nature. Once reactive dyes are commercial products they will be discharged to the waterways and rivers causing ecological damages and health problems. The aim of this paper was to consider the potential of two techniques for colour and toxicity removal: ionizing radiation and adsorption by zeolites synthesized from fly ash. Real effluents from chemical and textile industries (hardly coloured) were submitted to radiation and adsorption using zeolites. It was necessary to dilute some effluents prior the treatments in order to get any success. When electrons irradiation was performed radiation doses applied were from 0.5 kGy up to 20 kGy. This radiation process accounted for a partial decolouring as higher doses were implemented. Coal fly ashes were used as starting material for zeolite synthesis by means of hydrothermal treatment with alkaline medium. The adsorption was performed by batch experiments. It was obtained about 77% - 90% color removal from dye wastewater after 24h of contact time with two types of zeolite. The irradiation accounted for 72% of the initial toxicity. The ionizing radiation and adsorption by zeolites synthesized from fly ash can be used as an alternative for the treatment of aqueous waste containing dyes. (author)

  9. Repair of radiation damage of Micrococcus radioproteolyticus due to gamma and UV irradiation

    International Nuclear Information System (INIS)

    Ryznar, L.; Drasil, V.

    1982-01-01

    Cells were irradiated in dry state with gamma radiation and UV radiation. The post-irradiation warming of freeze dried cells (2 hours to 60deg or to 80deg) influenced the ability to repair sublethal damage. Heating to 80deg caused a mild reduction in survival. The repair of irradiated and heated cells required more time than that of cells which had only been irradiated. (M.D.)

  10. Identification of irradiated chicken meat using electron spin resonance spectroscopy

    International Nuclear Information System (INIS)

    Chawla, S.P.; Thomas, Paul

    2004-01-01

    Studies were carried out on detection of irradiation treatment in chicken using electron spin resonance (ESR) spectroscopy. The effect of gamma- irradiation treatment on radiation induced signal in different types of chicken namely, broiler, deshi and layers was studied. Irradiation treatment induced a characteristic ESR signal that was not detected in non-irradiated samples. The shape of the signal was not affected by type of the bone. The intensity of radiation induced ESR signal was affected by factors such as absorbed radiation dose, bone type irradiation temperature, post-irradiation storage, post-irradiation cooking and age of the bird. Deep-frying resulted in the formation of a symmetric signal that had a different shape and was weaker than the radiation induced signal. This technique can be effectively used to detect irradiation treatment in bone-in chicken meat even if stored and/or subjected to various traditional cooking procedures. (author)

  11. Dose controlled low energy electron irradiator for biomolecular films.

    Science.gov (United States)

    Kumar, S V K; Tare, Satej T; Upalekar, Yogesh V; Tsering, Thupten

    2016-03-01

    We have developed a multi target, Low Energy Electron (LEE), precise dose controlled irradiator for biomolecular films. Up to seven samples can be irradiated one after another at any preset electron energy and dose under UHV conditions without venting the chamber. In addition, one more sample goes through all the steps except irradiation, which can be used as control for comparison with the irradiated samples. All the samples are protected against stray electron irradiation by biasing them at -20 V during the entire period, except during irradiation. Ethernet based communication electronics hardware, LEE beam control electronics and computer interface were developed in house. The user Graphical User Interface to control the irradiation and dose measurement was developed using National Instruments Lab Windows CVI. The working and reliability of the dose controlled irradiator has been fully tested over the electron energy range of 0.5 to 500 eV by studying LEE induced single strand breaks to ΦX174 RF1 dsDNA.

  12. Dose controlled low energy electron irradiator for biomolecular films

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S. V. K., E-mail: svkk@tifr.res.in; Tare, Satej T.; Upalekar, Yogesh V.; Tsering, Thupten [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005 (India)

    2016-03-15

    We have developed a multi target, Low Energy Electron (LEE), precise dose controlled irradiator for biomolecular films. Up to seven samples can be irradiated one after another at any preset electron energy and dose under UHV conditions without venting the chamber. In addition, one more sample goes through all the steps except irradiation, which can be used as control for comparison with the irradiated samples. All the samples are protected against stray electron irradiation by biasing them at −20 V during the entire period, except during irradiation. Ethernet based communication electronics hardware, LEE beam control electronics and computer interface were developed in house. The user Graphical User Interface to control the irradiation and dose measurement was developed using National Instruments Lab Windows CVI. The working and reliability of the dose controlled irradiator has been fully tested over the electron energy range of 0.5 to 500 eV by studying LEE induced single strand breaks to ΦX174 RF1 dsDNA.

  13. Damage evolution in Xe-ion irradiated rutile (TiO2) single crystals

    International Nuclear Information System (INIS)

    Li, F.; Sickafus, K.E.; Evans, C.R.; Nastasi, M.

    1999-01-01

    Rutile (TiO 2 ) single crystals with (110) orientation were irradiated with 360 keV Xe 2+ ions at 300 K to fluences ranging from 2 x 10 19 to 1 x 10 20 Xe/m 2 . Irradiated samples were analyzed using: (1) Rutherford backscattering spectroscopy combined with ion channeling analysis (RBS/C); and (2) cross-sectional transmission electron microscopy (XTEM). Upon irradiation to a fluence of 2 x 10 19 Xe/m 2 , the sample thickness penetrated by the implanted ions was observed to consist of three distinct layers: (1) a defect-free layer at the surface (thickness about 12 nm) exhibiting good crystallinity; (2) a second layer with a low density of relatively large-sized defects; and (3) a third layer consisting of a high concentration of small defects. After the fluence was increased to 7 x 10 19 Xe/m 2 , a buried amorphous layer was visible by XTEM. The thickness of the amorphous layer was found to increase with increasing Xe ion fluence. The location of this buried amorphous layer was found to coincide with the measured peak in the Xe concentration (measured by RBS/C), rather than with the theoretical maximum in the displacement damage profile. This observation suggests the implanted Xe ions may serve as nucleation sites for the amorphization transformation. The total thickness of the damaged microstructure due to ion irradiation was always found to be much greater than the projected range of the Xe ions. This is likely due to point defect migration under the high stresses induced by ion implantation

  14. ESR investigataions of electron-beam irradiated cellulose nitrate

    International Nuclear Information System (INIS)

    Chipara, M.I.; Catana, D.; Grecu, V.; Romero, J.R.; Chipara, D.

    1994-01-01

    Electron spin resonance investigations on an electron-beam irradiated solid state nuclear track detector, based on cellulose nitrate (KODAK LR-311) are reported. The nature of free radicals induced in polymers by irradiation is discussed. The dependence of resonance spectral parameters on irradiation times, as well as on storage time and temperature, is studied. The experimental results are related to the stability of latent tracks and its is concluded that the free radicals induced by irradiation are located within the latent tracks. We have shown that both latent track and free radical thermal fading obey an Arrhenius-like dependence, with the same activation energy. (Author)

  15. ESR investigataions of electron-beam irradiated cellulose nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Chipara, M.I.; Catana, D. [Institute of Atomic Physics, Bucharest (Romania); Grecu, V.; Romero, J.R. [Bucharest Univ. (Romania). Faculty of Physics; Coca, S. [Chemical Research Inst., Bucharest (Romania); Chipara, D. [Research Inst. for Electrotechnics, Bucharest (Romania)

    1994-10-01

    Electron spin resonance investigations on an electron-beam irradiated solid state nuclear track detector, based on cellulose nitrate (KODAK LR-311) are reported. The nature of free radicals induced in polymers by irradiation is discussed. The dependence of resonance spectral parameters on irradiation times, as well as on storage time and temperature, is studied. The experimental results are related to the stability of latent tracks and its is concluded that the free radicals induced by irradiation are located within the latent tracks. We have shown that both latent track and free radical thermal fading obey an Arrhenius-like dependence, with the same activation energy. (Author).

  16. ESR investigations of electron-beam irradiated cellulose nitrate

    International Nuclear Information System (INIS)

    Chipara, M.I.; Grecu, V.; Catana, D.; Romero, J.R.; Coca, S.; Chipara, M.D.

    1994-01-01

    Electron spin resonance investigations on an electron-beam irradiated solid state nuclear track detector, based on cellulose nitrate (KODAK LR-311), are reported. The nature of free radicals induced in polymers by irradiation is discussed. The dependence of resonance spectral parameters on irradiation times, as well as on storage time and temperature, is studied. The experimental results are related to the stability of latent tracks and it is concluded that the free radicals induced by irradiation are located within the latent tracks. We have shown that both latent track and free radical thermal fading obey an Arrhenius-like dependence, with the same activation energy. (Author)

  17. Electron beam influence on the carbon contamination of electron irradiated hydroxyapatite thin films

    International Nuclear Information System (INIS)

    Hristu, Radu; Stanciu, Stefan G.; Tranca, Denis E.; Stanciu, George A.

    2015-01-01

    Highlights: • Carbon contamination mechanisms of electron-beam-irradiated hydroxyapatite. • Atomic force microscopy phase imaging used to detect carbon contamination. • Carbon contamination dependence on electron energy, irradiation time, beam current. • Simulation of backscattered electrons confirms the experimental results. - Abstract: Electron beam irradiation which is considered a reliable method for tailoring the surface charge of hydroxyapatite is hindered by carbon contamination. Separating the effects of the carbon contamination from those of irradiation-induced trapped charge is important for a wide range of biological applications. In this work we focus on the understanding of the electron-beam-induced carbon contamination with special emphasis on the influence of the electron irradiation parameters on this phenomenon. Phase imaging in atomic force microscopy is used to evaluate the influence of electron energy, beam current and irradiation time on the shape and size of the resulted contamination patterns. Different processes involved in the carbon contamination of hydroxyapatite are discussed

  18. Growth rate of dislocation loop in Fe-Ni-Cr alloy under Kr+ ion and electron irradiation

    International Nuclear Information System (INIS)

    Kimoto, T.; Allen, C.W.; Rehn, L.E.

    1991-10-01

    In order to examine the effect of irradiating particle species on the growth rate of radiation-induced dislocation loops, a solution-annealed Fe-25Ni-15Cr-0.02C alloy was irradiated at 723 K first by 1.5 MeV Kr + ions for 2520 sec, then by 1.5 MeV Kr + ions and 1.0 MeV electrons simultaneously for 780 sec, and finally by 1.0 MeV electrons for 780 sec with the HVEM-Tandem Facility in Argonne National Laboratory. The calculated damage rate by 1.5 MeV Kr + ions was 5.8 x 10 -4 dpa/s, and that by 1.0 MeV electrons was 1 x 10 -4 dpa/s. The growth rate of a dislocation loop located at the center of the specimen was 7 x 10 -3 nm/s for the Kr + ion irradiation, 4 x 10 -2 nm/s for the simultaneous Kr + and electron irradiation, and (2--3) x 10 -2 nm/s for the electron irradiation. This implies that the electron irradiation is about 19 times more effective in the growth of radiation-induced dislocation loops than the Kr + ion irradiation. The dislocation loop growth rate under the simultaneous Kr + and electron irradiation is higher than the sum of the growth rates under the individual Kr + and electron irradiations. 5 refs., 4 figs

  19. Testicular damage in rats fed on irradiated diets

    International Nuclear Information System (INIS)

    Kushwaha, A.K.S.; Hasan, S.S.

    1986-01-01

    Feeding effect of irradiated diets was studied on the pups born to mother fed either on irradiated normal diet or irradiated low protein diet. The study indicated that pups born to mother fed on the irradiated low protein diet had fewer spermatogonial cells in the testes than those given irradiated normal diet and unirradiated low protein diet. Similarly, pups maintained on the irradiated low protein diet showed marked decrease in alkaline phosphatase and cholesterol contents in the testes rather than in the pups fed irradiated normal as well as unirradiated low protein diets. The irradiated low protein diet fed pups showed increased depletion and vacuolization of adrenocortical and medullary cells. 13 refs., 15 figures. (author)

  20. Testicular damage in rats fed on irradiated diets

    Energy Technology Data Exchange (ETDEWEB)

    Kushwaha, A K.S.; Hasan, S S

    1986-12-01

    Feeding effect of irradiated diets was studied on the pups born to mother fed either on irradiated normal diet or irradiated low protein diet. The study indicated that pups born to mother fed on the irradiated low protein diet had fewer spermatogonial cells in the testes than those given irradiated normal diet and unirradiated low protein diet. Similarly, pups maintained on the irradiated low protein diet showed marked decrease in alkaline phosphatase and cholesterol contents in the testes rather than in the pups fed irradiated normal as well as unirradiated low protein diets. The irradiated low protein diet fed pups showed increased depletion and vacuolization of adrenocortical and medullary cells. 13 refs., 15 figures.

  1. Analysis of electron-irradiated poly-ether ether ketone by X-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Oyabu, Matashige; Kobayashi, Yoshinori; Seguchi, Tadao; Sasuga, Tsuneo; Kudoh, Hisaaki.

    1995-01-01

    Organic polymers used in atomic power plants or space are damaged by ionizing irradiation. Radicals produced by irradiation cause oxidation, chain scission and crosslinking, all of which lead to degradation of the material. In this paper, the surface of electron-irradiated poly-ether ether ketone (PEEK) was studied by X-ray photoelectron spectroscopy (XPS). The irradiation in air was found to oxidize the PEEK surface producing carboxyl groups, the content of which dependant on the dose. Carboxyl groups were not produced in helium gas. Quantitative spectral analysis indicated that the aromatic structure might be decomposed. Some comparison was made between the semicrystalline and amorphous samples. The oxygen content resulting from irradiation, of semicrystalline PEEK increased more than that of amorphous PEEK. (author)

  2. Investigation of instability of M23C6 particles in F82H steel under electron and ion irradiation conditions

    Science.gov (United States)

    Kano, Sho; Yang, Huilong; Shen, Jingjie; Zhao, Zishou; McGrady, John; Hamaguchi, Dai; Ando, Mamami; Tanigawa, Hiroyasu; Abe, Hiroaki

    2018-04-01

    In order to clarify the instability of M23C6 in F82H steel under irradiation, both electron irradiation using a high voltage electron microscope (HVEM) and ion irradiation using an ion accelerator were performed. For the electron irradiation, in-situ observation under 2 MV electron irradiation and ex-situ high resolution electron microscopic (HREM) analysis were utilized to evaluate the response of M23C6 against irradiation. The temperature dependence of the irradiation induced instability of the carbide was first confirmed: 293 K indicating severe loss of crystallinity due to dissolution of the constituent atoms though irradiation-enhanced diffusion under the vacancy diffusion by the focused electron beam irradiation. For the ion irradiation, 10.5 MeV-Fe3+ ion was applied to bombard the F82H steel at 673 K to achieve the displacement damage of ≈20 dpa at the depth of 1.0 μm from surface. Cross-section TEM specimens were prepared by a focused ion beam technique. The shrinkage of carbide particles was observed especially near the irradiation surface. Besides, the lattice fringes at the periphery of carbide were observed in the irradiated M23C6 by the HREM analysis, which is different from that observed in the electron irradiation. It was clarified that the instability of M23C6 is dependent on the irradiation conditions, indicating that the flow rate of vacancy type defects might be the key factor to cause the dissolution of constituent atoms of carbide particles into matrix under irradiation.

  3. Carboxylated nanodiamonds inhibit γ-irradiation damage of human red blood cells.

    Science.gov (United States)

    Santacruz-Gomez, K; Silva-Campa, E; Melendrez-Amavizca, R; Teran Arce, F; Mata-Haro, V; Landon, P B; Zhang, C; Pedroza-Montero, M; Lal, R

    2016-04-07

    Nanodiamonds when carboxylated (cNDs) act as reducing agents and hence could limit oxidative damage in biological systems. Gamma (γ)-irradiation of whole blood or its components is required in immunocompetent patients to prevent transfusion-associated graft versus host disease (TA-GVHD). However, γ-irradiation of blood also deoxygenates red blood cells (RBCs) and induces oxidative damage, including abnormalities in cellular membranes and hemolysis. Using atomic force microscopy (AFM) and Raman spectroscopy, we examined the effect of cNDs on γ-irradiation mediated deoxygenation and morphological damage of RBCs. γ-Radiation induced several morphological phenotypes, including stomatocytes, codocytes and echinocytes. While stomatocytes and codocytes are reversibly damaged RBCs, echinocytes are irreversibly damaged. AFM images show significantly fewer echinocytes among cND-treated γ-irradiated RBCs. The Raman spectra of γ-irradiated RBCs had more oxygenated hemoglobin patterns when cND-treated, resembling those of normal, non-irradiated RBCs, compared to the non-cND-treated RBCs. cND inhibited hemoglobin deoxygenation and morphological damage, possibly by neutralizing the free radicals generated during γ-irradiation. Thus cNDs have the therapeutic potential to preserve the quality of stored blood following γ-irradiation.

  4. Atomic structure of radiation damages in FCC-metals after neutron irradiation

    International Nuclear Information System (INIS)

    Popova, E.V.; Ivchenko, V.A.; Kozlov, A.V.

    2005-01-01

    Full text: Radiation clusters, formed at a neutron irradiation, are a product of evolution of cascade areas. The quantitative information about clusters can be used for verification of calculations of cascade damage ability, in particular, cascade efficiency. Data about concentration clusters and an average of the vacancies containing in them, allow to receive total of the vacancies reserved in them and to use them for comparison to results of calculations of cascade damage ability. A correctness of such comparison by that above, than below temperature of a neutron irradiation. The purpose of work was experimental studying radiation clusters formed in FCC-metals at a low temperature neutron irradiation methods of dilatometry, field ion (FIM) and transmission electronic microscopy (TEM). Radiation clusters were studied: in industrial austenite steel C0.05Crl6Nil5Mo2Mnl, irradiated in reactor Rw-2a at temperature 310 K up to fluence intermediate and fast neutrons (with E > 0,1 MeV) 6.7·l0 21 m -2 ; in a modelling material - Pt (cleanliness of 99.99 %) with the same - FCC-structure in an initial condition and after an irradiation in reactor RWW-2M at temperature 310 K up to fluence intermediate and fast neutrons (with E > 0.1 MeV) 3.5·10 22 m -2 . As a result of an irradiation of steel and pure Pt, in these materials by methods FIM and TEM many radiation clusters, the accelerated neutrons initiated by interaction with substance was revealed. It is established that these damage areas represent the depleted zones containing separate vacancies, and also small vacancy complexes, with the 'belt' interstitial atoms. The quantitative estimation of the sizes of such radiating defects is lead and their density in volume is experimentally established. So the neutron irradiation of steel at temperature 310 K up to fluence 6.7·10 21 m -2 causes formation radiation clusters which average diameter according to TEM makes 3 nanometers. Observable by methods FIM clusters have the

  5. Influence of high-energy electron irradiation on field emission properties of multi-walled carbon nanotubes (MWCNTs) films

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Sandip S. [Center for Advanced Studies in Material Science and Condensed Matter Physics, Department of Physics, University of Pune, Pune 411007 (India); Koinkar, Pankaj M. [Center for International Cooperation in Engineering Education (CICEE), University of Tokushima, 2-1 Minami-Josanjima-Cho, Tokushima 770-8506 (Japan); Dhole, Sanjay D. [Center for Advanced Studies in Material Science and Condensed Matter Physics, Department of Physics, University of Pune, Pune 411007 (India); More, Mahendra A., E-mail: mam@physics.unipune.ac.i [Center for Advanced Studies in Material Science and Condensed Matter Physics, Department of Physics, University of Pune, Pune 411007 (India); Murakami, Ri-ichi, E-mail: murakami@me.tokushima-u.ac.j [Department of Mechanical Engineering, University of Tokushima, 2-1 Minami-Josanjima-Cho, Tokushima 770-8506 (Japan)

    2011-04-15

    The effect of very high energy electron beam irradiation on the field emission characteristics of multi-walled carbon nanotubes (MWCNTs) has been investigated. The MWCNTs films deposited on silicon (Si) substrates were irradiated with 6 MeV electron beam at different fluence of 1x10{sup 15}, 2x10{sup 15} and 3x10{sup 15} electrons/cm{sup 2}. The irradiated films were characterized using scanning electron microscope (SEM) and micro-Raman spectrometer. The SEM analysis clearly revealed a change in surface morphology of the films upon irradiation. The Raman spectra of the irradiated films show structural damage caused by the interaction of high-energy electrons. The field emission studies were carried out in a planar diode configuration at the base pressure of {approx}1x10{sup -8} mbar. The values of the threshold field, required to draw an emission current density of {approx}1 {mu}A/cm{sup 2}, are found to be {approx}0.52, 1.9, 1.3 and 0.8 V/{mu}m for untreated, irradiated with fluence of 1x10{sup 15}, 2x10{sup 15} and 3x10{sup 15} electrons/cm{sup 2}. The irradiated films exhibit better emission current stability as compared to the untreated film. The improved field emission properties of the irradiated films have been attributed to the structural damage as revealed from the Raman studies.

  6. Precipitation in Ni-Si during electron and ion irradiation

    Science.gov (United States)

    Lucas, G. E.; Zama, T.; Ishino, S.

    1986-11-01

    This study was undertaken to further investigate how the nature of the irradiation condition affects precipitation in a dilute Ni-Si system. Transmission electron microscopy (TEM) discs of a solution annealed Ni alloy containing 5 at% Si were irradiated with 400 keV Ar + ions, 200 keV He + ions and 1 MeV electrons at average displacement rates in the range 2 × 10 -5dpa/s to 2 × 10 -3dpa/s at temperatures in the range 25°C to 450°C. Samples irradiated with electrons were observed in situ in an HVEM, while ion irradiated specimens were examined in a TEM after irradiation. Precipitation of Ni 3Si was detected by the appearance of superlattice spots in the electron diffraction patterns. It was found that as the mass of the irradiating species increased, the lower bound temperature at which Ni 3Si precipitation was first observed increased. For electron irradiation, the lower bound temperature at 2 × 10 -3dpa/s was ˜125°C, whereas for 400 keV Ar + irradiation at a similar average displacement rate the lower boundary was approximately 325°C. This suggests that cascade disordering competes with radiation induced solute segregation.

  7. Precipitation in Ni-Si during electron and ion irradiation

    International Nuclear Information System (INIS)

    Lucas, G.E.; Zama, T.; Ishino, S.

    1986-01-01

    This study was undertaken to further investigate how the nature of the irradiation condition affects precipitation in a dilute Ni-Si system. Transmission electron microscopy (TEM) discs of a solution annealed Ni alloy containing 5 at% Si were irradiated with 400 keV Ar + ions, 200 keV He + ions and 1 MeV electrons at average displacement rates in the range 2x10 -5 dpa/s to 2x10 -3 dpa/s at temperatures in the range 25 0 C to 450 0 C. Samples irradiated with electrons were observed in situ in an HVEM, while ion irradiated specimens were examined in a TEM after irradiation. Precipitation of Ni 3 Si was detected by the appearance of superlattice spots in the electron diffraction patterns. It was found that as the mass of the irradiating species increased, the lower bound temperature at which Ni 3 Si precipitation was first observed increased. For electron irradiation, the lower bound temperature at 2x10 -3 dpa/s was ∝125 0 C, whereas for 400 keV Ar + irradiation at a similar average displacement rate the lower boundary was approximately 325 0 C. This suggests that cascade disordering competes with radiation induced solute segregation. (orig.)

  8. Electron irradiation-induced defects in {beta}-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, Ryuichiro [Osaka Prefectural Univ., Sakai (Japan). Reseach Inst. for Advanced Science and Technology

    1996-04-01

    To add information of point defects in cubic crystal SiC, polycrystal {beta}-SiC on the market was used as sample and irradiated by neutron and electron. In situ observation of neutron and electron irradiation-induced defects in {beta}-SiC were carried out by ultra high-voltage electronic microscope (UHVEM) and ordinary electronic microscope. The obtained results show that the electron irradiation-induced secondary defects are micro defects less than 20 nm at about 1273K, the density of defects is from 2x10{sup 17} to 1x10{sup 18}/cc, the secondary defects may be hole type at high temperature and the preexistant defects control nuclear formation of irradiation-induced defects, effective sink. (S.Y.)

  9. Using electron irradiation to probe iron-based superconductors

    Science.gov (United States)

    Cho, Kyuil; Kończykowski, M.; Teknowijoyo, S.; Tanatar, M. A.; Prozorov, R.

    2018-06-01

    High-energy electron irradiation at low temperatures is an efficient and controlled way to create vacancy–interstitial Frenkel pairs in a crystal lattice, thereby inducing nonmagnetic point-like scattering centers. In combination with London penetration depth and resistivity measurements, the electron irradiation was used as a phase-sensitive probe to study the superconducting order parameter in iron-based superconductors (FeSCs), lending strong support to sign-changing s ± pairing. Here, we review the key results of the effect of electron irradiation in FeSCs.

  10. Changing in tool steels wear resistance under electron irradiation

    International Nuclear Information System (INIS)

    Braginskaya, A.E.; Manin, V.N.; Makedonskij, A.V.; Mel'nikova, N.A.; Pakchanin, L.M.; Petrenko, P.V.

    1983-01-01

    The tool steels and alloys wear resistance under dry friction after electron irradiation has been studied. Electron irradiation of a wide variety of steels is shown to increase wear resistance. In this case phase composition and lattice parameters changes are observed both in matrix and carbides. The conclusion is drawn that an appreciable increase of steel wear resistance under electron irradiation can be explained both by carbide phase volume gain and changes in it's composition and the formation of carbide phase submicroscopic heterogeneities and, possibly, complexes of defects

  11. Effect of electron beam irradiation on pollen mother cells of gladiolus 'chaoji'

    International Nuclear Information System (INIS)

    Zhang Zhiwei; Wang Dan; Wen Fangping Zhang Xiaoxue

    2008-01-01

    In order to test the effects of various doses of electron beam on M1 generation pollen mother cells (PMC), the corm of gladiolus 'chaoji' was irradiated by electron beam with 3 MeV energy. Some abnormalities of meiosis of pollen mother cells were studied and the bands of protein subunit were analyzed by SDS-PAGE for the irradiated corm. The genetic damage at meiosis of gladiolus is observed, and the types of chromosomal aberrations are laggard chromosomes, chromosomal bridge, chromosome outside nucleus, unequal separation of chromosome, micronuclei and so on. Some trispores and paraspores are viewed at tetraspore period. The shape and size of the microspores vary in some treated materials, and most of microspores display little volume. The statistic of aberrance types and frequencies in PMCs show that aberrance types are chromosome outside nucleus and micronuclei mostly. The SDS-PAGE result shows that protein expression of M1 generation pollen is obviously changed by electron beam irradiation. Low dose of electron beam has obvious effects, and some special proteins subunit bands are found among varieties of irradiation dosage respectively. The protein bands are absent at the dose more than 160 Gy compared to low dose of electron beam. The results indicate that electron beam irradiation is an effective way for gladiolus breeding. (authors)

  12. Effects of electron beam irradiation on cut flowers and mites

    International Nuclear Information System (INIS)

    Dohino, Toshiyuki; Tanabe, Kazuo

    1994-01-01

    Two spotted spider mite, Tetranychus urticae KOCH were irradiated with electron beams (2.5MeV) to develop an alternative quarantine treatment for imported cut flowers. The tolerance of eggs increased with age (1-5-day-old). Immature stages (larva-teleiochrysalis) irradiated at 0.4-0.8kGy increased tolerance with their development. Mated mature females irradiated at 0.4kGy or higher did not produce viable eggs, although temporary recovery was observed at 0.2kGy. Adult males were sterilized at 0.4kGy because non-irradiated virgin females mated with yielded female progeny malformed and sterilized. Various effects of electron beam irradiation were observed when nine species of cut flowers were irradiated in 5MeV Dynamitron accelerator. Chrysanthemum and rose were most sensitive among cut flowers. (author)

  13. Mouse skin damages caused by fractionated irradiation with carbon ions

    Energy Technology Data Exchange (ETDEWEB)

    Ando, K; Chen, Y J; Ohira, C; Nojima, K; Ando, S; Kobayashi, N; Ohbuchi, T; Shimizu, W [Space and Particle Radiation Science Research Group, Chiba (Japan); Koike, S; Kanai, T [National Inst. of Radiological Sciences, Chiba (Japan). Div. of Accelerator Physics

    1997-09-01

    We have investigated carbon-dose responses of early and late skin damages after daily fractionations to the mouse leg. Depilated legs were irradiated with 7 different positions within 290 MeV/u carbon beams. Fractionation schedules were 1, 2, 4 and 8 daily fractions. Skin reaction was scored every other day for 32 days. Five highest scores in individual mice were averaged, and used as averaged peak reaction. The isoeffect doses to produce an averaged peak skin reaction of 3.0 (moist desquamation) on dose-response curves were calculated with 95% confidence limit. The isoeffect dose for control gamma rays constantly increased with an increase in the number of fraction. The isoeffect doses in low LET carbon ions of 14- and 20 keV/{mu}m also increased up to 4 fractions, but did not increase when 4 fractions increased to 8 fractions. The saturation of isoeffect dose was more prominently observed for 40 keV/{mu}m in such that the isoeffect doses did not change among 2, 4 and 8 fractions. The isoeffect doses for LET higher than 50 keV/{mu}m were smaller than those for lower LET. However, the isoeffect doses for 50-, 60-, 80- and 100 keV/{mu} steadily increased with an increase in the number of fraction and did not show any saturation up to 8 fractions. Relation between LET and RBE was linear for all fractionation schedules. The slope of regression line in 4 fractions was steepest, and significantly (P<0.05) different from that in 1 fraction. (orig.)

  14. Mouse skin damages caused by fractionated irradiation with carbon ions

    International Nuclear Information System (INIS)

    Ando, K.; Chen, Y.J.; Ohira, C.; Nojima, K.; Ando, S.; Kobayashi, N.; Ohbuchi, T.; Shimizu, W.; Koike, S.; Kanai, T.

    1997-01-01

    We have investigated carbon-dose responses of early and late skin damages after daily fractionations to the mouse leg. Depilated legs were irradiated with 7 different positions within 290 MeV/u carbon beams. Fractionation schedules were 1, 2, 4 and 8 daily fractions. Skin reaction was scored every other day for 32 days. Five highest scores in individual mice were averaged, and used as averaged peak reaction. The isoeffect doses to produce an averaged peak skin reaction of 3.0 (moist desquamation) on dose-response curves were calculated with 95% confidence limit. The isoeffect dose for control gamma rays constantly increased with an increase in the number of fraction. The isoeffect doses in low LET carbon ions of 14- and 20 keV/μm also increased up to 4 fractions, but did not increase when 4 fractions increased to 8 fractions. The saturation of isoeffect dose was more prominently observed for 40 keV/μm in such that the isoeffect doses did not change among 2, 4 and 8 fractions. The isoeffect doses for LET higher than 50 keV/μm were smaller than those for lower LET. However, the isoeffect doses for 50-, 60-, 80- and 100 keV/μ steadily increased with an increase in the number of fraction and did not show any saturation up to 8 fractions. Relation between LET and RBE was linear for all fractionation schedules. The slope of regression line in 4 fractions was steepest, and significantly (P<0.05) different from that in 1 fraction. (orig.)

  15. Thermal damage produced by high-irradiance continuous wave CO2 laser cutting of tissue.

    Science.gov (United States)

    Schomacker, K T; Walsh, J T; Flotte, T J; Deutsch, T F

    1990-01-01

    Thermal damage produced by continuous wave (cw) CO2 laser ablation of tissue in vitro was measured for irradiances ranging from 360 W/cm2 to 740 kW/cm2 in order to investigate the extent to which ablative cooling can limit tissue damage. Damage zones thinner than 100 microns were readily produced using single pulses to cut guinea pig skin as well as bovine cornea, aorta, and myocardium. Multiple pulses can lead to increased damage. However, a systematic decrease in damage with irradiance, predicted theoretically by an evaporation model of ablation, was not observed. The damage-zone thickness was approximately constant around the periphery of the cut, consistent with the existence of a liquid layer which stores heat and leads to tissue damage, and with a model of damage and ablation recently proposed by Zweig et al.

  16. Development of UV absorbing PET through Electron Irradiation

    International Nuclear Information System (INIS)

    Kim, Jung Woo; Lee, Na Eun; Lim, Hyung San; Park, Yang Jeong; Cho, Sung Oh

    2017-01-01

    Experiment to increase UV absorbance through electron beam irradiation on PET was performed. Moreover, surface hardness and roughness of each sample were observed to find the key factor increasing UV absorbance. PET sheets were irradiated with an electron beam at various fluences. The irradiated samples, as well as pristine sample, were subjected to UV-visible spectral study(UV-Vis), pencil hardness test, and scanning electron microscopy(SEM) experiment. In this study, PET samples irradiated at several conditions were analyzed through various measurements. UV absorbance-another meaning of transmittance in this study- of irradiated PET sample increased compared with pristine sample as fluence was increased in UV-Visible spectroscopy experiment.

  17. Radiation damage studies on STAR250 CMOS sensor at 300 keV for electron microscopy

    International Nuclear Information System (INIS)

    Faruqi, A.R.; Henderson, R.; Holmes, J.

    2006-01-01

    There is a pressing need for better electronic detectors to replace film for recording high-resolution images using electron cryomicroscopy. Our previous work has shown that direct electron detection in CMOS sensors is promising in terms of resolution and efficiency at 120 keV [A.R. Faruqi, R. Henderson, M. Prydderch, R. Turchetta, P. Allport, A. Evans, Nucl. Instr. and Meth. 546 (2005) 170], but in addition, the detectors must not be damaged by the electron irradiation. We now present new measurements on the radiation tolerance of a 25 μm pitch CMOS active-pixel sensor, the STAR250, which was designed by FillFactory using radiation-hard technology for space applications. Our tests on the STAR250 aimed to establish the imaging performance at 300 keV following irradiation. The residual contrast, measured on shadow images of a 300 mesh grid, was >80% after corrections for increased dark current, following irradiation with up to 5x10 7 electrons/pixel (equivalent to 80,000 electron/μm 2 ). A CMOS sensor with this degree of radiation tolerance would survive a year of normal usage for low-dose electron cryomicroscopy, which is a very useful advance

  18. Effect of electron beam irradiation on fisheries water

    International Nuclear Information System (INIS)

    Sarala Selambakkannu; Khomsaton Abu Bakar; Jamaliah Shariff; Suhairi Alimon

    2012-01-01

    This paper studies about water obtained from fish pond of fisheries research centre. Usual water quality parameters such as pH, COD, Turbidity and Ammonia content were analyzed before and after irradiation. Electron beam irradiation was used to irradiate the water with the dose 100 kGy, 200 kGy and 300 kGy. Only high dose was applied on this water as only a limited amount of samples was supplied. All the parameters indicated a slight increase after irradiation except for the ammonia content, which showed a gradual decrease as irradiation dose increases. Sample condition was changed before irradiation in order to obtain more effective results in the following batch. The water sample from fisheries was diluted with distilled water to the ratio of 1:1.This was followed with irradiation at 100 kGy, 200 kGy and 300 kGy. The results still showed an increase in all parameters after irradiation except for ammonia content. For the following irradiation batch, the pH of the sample was adjusted to pH 4 and pH 8 before irradiation. For this sample the irradiation dose selected was only 100 kGy. A higher value of ammonia was observed for the sample with pH 4 after irradiation. Other parameters were almost the same as the first two batches. (author)

  19. Electron beam irradiation on cation exchanger used for strontium recovery

    International Nuclear Information System (INIS)

    Watanabe, Sou; Nakamura, Masahiro; Nomura, Kazunori; Nakajima, Yasuo; Okamoto, Yoshihiro

    2014-01-01

    Titanate is promising material for radioactive Sr recovery from liquid waste generated in the nuclear facilities. "9"0Sr is one of the most important nuclides in order to release the liquid waste into the environment due to its strong beta-ray decay energy. Although the titanate is applied to radioactive Sr decontamination facility, their resistance to irradiations from radioactive elements adsorbed is not widely investigated so far. In this study, durability of a hydrous titanic acid ion exchanger against beta-ray irradiation were evaluated through electron beam irradiation, elution behaviour of Sr after the irradiation and local structural analysis of the titanate. 1.4 MGy irradiation led to 1% of Sr elution, and the elution could be attributed to defects of O in the titanate induced by the irradiation. Chemical state of Ti of the titanate must be stable up to 2.7 MGy irradiation. (author)

  20. Generation and development of damage in double forged tungsten in different combined regimes of irradiation with extreme heat loads

    Science.gov (United States)

    Paju, Jana; Väli, Berit; Laas, Tõnu; Shirokova, Veroonika; Laas, Katrin; Paduch, Marian; Gribkov, Vladimir A.; Demina, Elena V.; Prusakova, Marina D.; Pimenov, Valeri N.; Makhlaj, Vadym A.; Antonov, Maksim

    2017-11-01

    Armour materials in fusion devices, especially in the region of divertor, are exposed to a continuous heat and particle load. In addition, several off-normal events can reach the material during a work session. Calculations show that the effects of plasma and heat during such events can lead to cracking, erosion and detachment of the armour material. On the other hand, mutual and combined influences of different kinds of heat and particle loads can lead to the amplification of defects or vice versa, to the mitigation of damages. Therefore, the purpose of the study is to investigate the plasma induced damages on samples of double forged tungsten, which is considered a potential candidate for armour material of future tokamak's divertor. The combined effect of different kinds of plasma induced damages was investigated and analysed in this research. The study was conducted by irradiating the samples in various irradiation regimes twice, to observe the accumulation of the damages. Afterwards the analysis of micro-topography, scanning electron microscopy images and electrical conductivity measurements was used. Results indicate that double-forging improved the tungsten's durability to irradiation. Nevertheless, powerful pulses lead to significant damage of the sample, which will lead to further deterioration in the bulk. Although the average micro-roughness on the sample's surface does not change, the overall height/depth ratios can change.

  1. Technology of irradiation of liquids by electron beams

    International Nuclear Information System (INIS)

    Tofaute, K.

    1979-01-01

    The methods of pretreatment, the technical details of the irradiating equipment, the applied radiation doses and the general requirements of the effectively working system are described. The extent of reinfection is compared in cases of heat-treated and electron-irradiated mud. The latter method gave significantly better results. (L.E.)

  2. The effect of composition, electron irradiation and quenching on ...

    Indian Academy of Sciences (India)

    The ionic conductivity at room temperature exhibits a characteristic double peak for the composition = 20 and 70. Both electron beam irradiation and quenching at low temperature have resulted in an increase in conductivity by 1–2 orders of magnitude. The enhancement of conductivity upon irradiation and quenching is ...

  3. Regeneration of used activated carbon by electron beam irradiation

    International Nuclear Information System (INIS)

    Arai, H.; Hosono, M.; Zhu, G.; Miyata, T.

    1992-01-01

    The adsorbing power of granular activated carbons which adsorbed sodium laurylsulfate were most effectively recovered by irradiation of high energy electron beams in nitrogen stream, and the carbon was hardly lost by irradiation. The regeneration was induced mainly by microscopic heating of adsorption sites. Regeneration was also confirmed by adsorption endotherms. Regeneration cost was tentatively evaluated. (author)

  4. Effects of electron beam irradiation on tin dioxide gas sensors

    Indian Academy of Sciences (India)

    WINTEC

    sensitivity increases more rapidly under high doses of irra- diation than under low doses of irradiation. The electron beam irradiation effects were simulated and the mecha- nism was discussed. Acknowledgements. The authors gratefully acknowledge financial support from the MOST 973 program, grant no. 2006CB705604 ...

  5. Space-charge dynamics of polymethylmethacrylate under electron beam irradiation

    CERN Document Server

    Gong, H; Ong, C K

    1997-01-01

    Space-charge dynamics of polymethylmethacrylate (PMMA) under electron beam irradiation has been investigated employing a scanning electron microscope. Assuming a Gaussian space-charge distribution, the distribution range (sigma) has been determined using a time-resolved current method in conjunction with a mirror image method. sigma is found to increase with irradiation time and eventually attain a stationary value. These observations have been discussed by taking into account radiation-induced conductivity and charge mobility. (author)

  6. Effect of hydration on the annealing of chemical radiation damage in gamma-irradiated strontium bromate

    International Nuclear Information System (INIS)

    Nair, S.M.K.; Sahish, T.S.

    1991-01-01

    Rehydration of γ-irradiated anhydrous strontium bromate induces direct recovery of damage. The recovery process is unimolecular and the rehydrated salt is susceptible to thermal annealing. (author) 11 refs.; 2 figs

  7. Method of determining the position of an irradiated electron beam

    International Nuclear Information System (INIS)

    Fukuda, Wataru.

    1967-01-01

    The present invention relates to the method of determining the position of a radiated electron beam, in particular, the method of detecting the position of a p-n junction by a novel method when irradiating the electron beam on to the semi-conductor wafer, controlling the position of the electron beam from said junction. When the electron beam is irradiated on to the semi-conductor wafer which possesses the p-n junction, the position of the p-n junction may be ascertained to determine the position of the irradiated electron beam by detecting the electromotive force resulting from said p-n junction with a metal disposed in the proximity of but without mechanical contact with said semi-conductor wafer. Furthermore, as far as a semi-conductor wafer having at least one p-n junction is concerned, the present invention allows said p-n junction to be used to determine the position of an irradiated electron beam. Thus, according to the present invention, the electromotive force of the electron beam resulting from the p-n junction may easily be detected by electrostatic coupling, enabling the position of the irradiated electron beam to be accurately determined. (Masui, R.)

  8. Waste treatment by microwave and electron beam irradiation

    International Nuclear Information System (INIS)

    Martin, D.; Craciun, G.; Manaila, E.; Ighigeanu, D; Oproiu, C.; Iacob, N.; Togoe, I.; Margaritescu, I.

    2007-01-01

    Comparative results obtained by applying separate and combined (successive and simultaneous) electron beam (EB) and microwave (MW) irradiation to waste treatment, such as food residuals (minced beef, wheat bran and wheat flour) and sewage sludge performed from a food industry wastewater treatment station (vegetable oil plant), are presented. The research results demonstrated that the simultaneous EB and MW irradiation produces the biggest reduction of microorganisms. The tests also demonstrated that the irradiation time and the upper limit of required EB absorbed dose, which ensures a complete sterilization effect, could be reduced by a factor of two by an additional use of MW energy to EB irradiation

  9. Damage production by fast electrons in dilute alloys of vanadium, niobium and molybdenum

    International Nuclear Information System (INIS)

    Jung, P.

    1975-01-01

    Vanadium, niobium and molybdenum samples containing about 300 ppm of zirconium were irradiated at helium temperature with electrons of energies between 0,6 and 3.1 MeV. The measured damage rates were analysed in terms of minimum threshold energy, damage function and resistivity per unit concentration of Frenkel pairs. For the minimum threshold energy T(Sub)d, values of 25+-2 eV (V) 28+-2 e V(Nb) and 34+-2 e V(Mo) were obtained. Pronounced differences between the displacement functions of molybdenum and that of niobium and vanadium are found which are explained by different stability of the defects during the irradiation at helium temperature

  10. Contribution of scanning Auger microscopy to electron beam damage study

    International Nuclear Information System (INIS)

    Fontaine, J.M.

    1983-04-01

    Electron bombardment can produce surface modifications of the analysed sample. The electron beam effects on solid surfaces which have been discussed in the published literature can be classified into the following four categories: (1) heating and its consequent effects, (2) charge accumulation in insulators and its consequent effects, (3) electron stimulated adsorption (ESA), and (4) electron stimulated desorption and/or decomposition (ESD). In order to understand the physico-chemical processes which take place under electron irradiation in an Al-O system, we have carried out experiments in which, effects, such as heating, charging and gas contamination, were absent. Our results point out the role of an enhanced surface diffusion of oxygen during electron bombardment of an Al (111) sample. The importance of this phenomenon and the contribution of near-elastic scattering of the primary electrons (5 keV) to the increase of the oxidation degree observed on Al (111) are discussed, compared to the generally studied effects

  11. Sterilization of ground spices by electron beams irradiation

    International Nuclear Information System (INIS)

    Hashigiwa, Masayuki; Nakachi, Ayako; Kobayashi, Hiroshi

    1999-01-01

    Each ground spice (Black Pepper, Turmeric, Ginger, Paprika and Basil), which was packaged into polyethylene film, was irradiated by electron beams at 5 different levels: 2, 4, 6, 8 and 10 kGy. Bacteriological tests for total bacterial count were carried out on spices before and after irradiation, but the tests for microfiora were carried out only before irradiation. Total bacterial count decreased in proportion to the level of electron beams. But the decreasing rate for Turmeric, Ginger and Basil was lower compared with that of other spices. The reason seems that rate of contamination by B. pumilus, which is thought as radiation resistant bacteria, was higher on these spices. (author)

  12. Sterilization of ground spices by electron beams irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hashigiwa, Masayuki; Nakachi, Ayako; Kobayashi, Hiroshi [K. Kobayashi and Co., Ltd., Kako, Hyogo (Japan)

    1999-09-01

    Each ground spice (Black Pepper, Turmeric, Ginger, Paprika and Basil), which was packaged into polyethylene film, was irradiated by electron beams at 5 different levels: 2, 4, 6, 8 and 10 kGy. Bacteriological tests for total bacterial count were carried out on spices before and after irradiation, but the tests for microfiora were carried out only before irradiation. Total bacterial count decreased in proportion to the level of electron beams. But the decreasing rate for Turmeric, Ginger and Basil was lower compared with that of other spices. The reason seems that rate of contamination by B. pumilus, which is thought as radiation resistant bacteria, was higher on these spices. (author)

  13. Electronic-excitation induced radiation damage in glasses

    Energy Technology Data Exchange (ETDEWEB)

    Vigouroux, J P

    1985-01-01

    In order to understand the microscopic nature of radiation induced defects in insulators, we have studied localization of negative and positive charges in amorphous and monocrystalline SiO2. The behaviour of these charges is linked to creation of point defects by electronic excitation. The role of intense electric fields under irradiation is pointed out.

  14. Application of EPR, thermoluminescence as well as DNA damage examination methods and sprout inhibition for identification of irradiated food

    International Nuclear Information System (INIS)

    Malec-Czechowska, K.; Stachowicz, W.; Dancewicz, A.M.; Szot, Z.

    1998-01-01

    Irradiation of food with doses up to 10 kGy of gamma, X-rays or electron beam is a relatively new technology improving hygienic quality of food, diminishing morbidity due to food pathogens and reducing losses during food storage. Application of this technology increases constantly in the world; more and more irradiated food appears on the market in various countries. In Europe it is agreed notion that detection of irradiated foods should be obligatory procedure included into administrative control system of foodstuffs. For this purpose the reliable methods are needed by which detection of irradiation fact will be possible. Such methods are not easy to be worked out because irradiation induces changes which are to small to be detected by methods commonly applied for food control. Working out the methods suitable for identification of irradiated food has been carried out in many countries in the world and during the last decade within several local and/or international programmes including the intercomparison of results obtained in different laboratories. In our institute such investigations began already in the 80-ties using EPR spectrometry and thermoluminescence measurements. Applications of these methods were approved in 1996 as European Community Standards. Other methods are still under investigation. They include the analyses of DNA damage in irradiated foodstuffs of animal or plant origin and measurements of germination effectiveness of irradiated grains and fruits. In this communication we present some results obtained upon application of forementioned methods to detection of different kinds of food irradiated with gamma rays or electron beam. (author)

  15. The reaction rates of electrons with native and irradiated ribonuclease

    International Nuclear Information System (INIS)

    Schuessler, H.; Ebert, M.; Davies, J.V.

    1977-01-01

    The rate of reaction of hydrated electrons with proteins depends, amongst other things, on the conformational structure of the protein, and irradiation itself causes conformational changes in proteins. A study has been made of variations in the reaction rates of hydrated electrons with RNase pre-irradiated by the Linac or by a 60 Co γ-source. The reaction rate constants varied with the pre-irradiation dose, the concentration of phosphate buffer, the enzyme concentration and also the presence of 10 -2 M ethanol. These variations serve to emphasize the importance of the tertiary structure of biological molecules in irradiation processes and have significant implications in the mathematical analysis of the inactivation of enzymes in steady-state irradiation processes. (U.K.)

  16. Strengthening of Poly Methyl Methacrylate (PMMA) through Electron Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Sung Ho; Lim, Hyung San; Ha, Jun Mok; Cho, Sung Oh [KAIST, Daejeon (Korea, Republic of)

    2015-05-15

    Poly Methyl Methacrylate (PMMA) was previously known to show the deteriorating mechanical properties when irradiated with electrons. This is true for low electron irradiation does, but it was found, through experimentation, that at high irradiation dose, PMMA demonstrates improved mechanical properties. With enough electron irradiation dose, the scissions can form new links amongst one another to achieve stability that surpasses that of the PMMA in pre-irradiation treatment state. With higher irradiation dosage and beam strength, hardness of irradiated PMMA could be increased to a much greater extent. Electrons with 50keV of energy can only penetrate around 30 μm of PMMA, thus increasing the beam energy could potentially allow for hardening of not just the surface of the PMMA samples, but the whole samples themselves. Furthermore, Pencil Hardness Test is a method to roughly analyze a material's hardness and does not provide an accurate feedback on the mechanical properties of the material of interest. Hence, a more thorough and effective method of measuring data from the use of equipment such as IZOD Impact Tester, Strain-Stress Tester and Haze Meter will be utilized in the future.

  17. Application of electron beam irradiation, (1). Development and application of electron beam processors

    International Nuclear Information System (INIS)

    Katsumura, Yosuke

    1994-01-01

    This paper deals with characteristics, equipment (principle and kinds), present conditions, and future issues in the application of electron beam irradiation. Characteristics of electron beams are described in terms of the following: chemical and biological effects of radiation; energy and penetrating power of electron beams; and principle and kinds of electron beam accelerator. Industrial application of electron beam irradiation has advantages of high speed procedure and producibility, less energy, avoidance of poisonous gas, and extreme reduction of organic solvents to be used. The present application of electron beam irradiation cen be divided into the following: (1) hardening of resin or coated membrane; (2) improvement of macromolecular materials; (3) environmental protection; (4) sterilization; (5) food sterilization. The present equipment for electron beam irradiation is introduced according to low energy, medium energy, and high energy equipment. Finally, future issues focuses on (1) the improvement of traceability system and development of electron dosimetric techniques and (2) food sterilization. (N.K.)

  18. On the threshold of damage formation in aluminum oxide via electronic excitations

    Energy Technology Data Exchange (ETDEWEB)

    Skuratov, V.A., E-mail: skuratov@jinr.ru [Joint Institute for Nuclear Research, Dubna (Russian Federation); O’Connell, J. [Centre for HRTEM, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Kirilkin, N.S. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Neethling, J. [Centre for HRTEM, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa)

    2014-05-01

    This work is aimed to determine the threshold of dense ionization induced damage formation and their morphology in sapphire single crystals irradiated with 1.2 MeV/amu Xe ions. Cross-sectional TEM examination of r-oriented Al{sub 2}O{sub 3} specimens irradiated to fluences of 2 × 10{sup 12} and 2 × 10{sup 13} cm{sup −2} has revealed discontinuous ion tracks visible from the irradiated surface up to a depth of 7.6 ± 0.1 μm. According to the SRIM code calculation, the threshold electronic stopping power for track formation in Al{sub 2}O{sub 3} is within the range 9.8 ÷ 10.5 keV/nm. This value agrees with those predicted by both inelastic and analytical thermal spike models.

  19. On the threshold of damage formation in aluminum oxide via electronic excitations

    International Nuclear Information System (INIS)

    Skuratov, V.A.; O’Connell, J.; Kirilkin, N.S.; Neethling, J.

    2014-01-01

    This work is aimed to determine the threshold of dense ionization induced damage formation and their morphology in sapphire single crystals irradiated with 1.2 MeV/amu Xe ions. Cross-sectional TEM examination of r-oriented Al 2 O 3 specimens irradiated to fluences of 2 × 10 12 and 2 × 10 13 cm −2 has revealed discontinuous ion tracks visible from the irradiated surface up to a depth of 7.6 ± 0.1 μm. According to the SRIM code calculation, the threshold electronic stopping power for track formation in Al 2 O 3 is within the range 9.8 ÷ 10.5 keV/nm. This value agrees with those predicted by both inelastic and analytical thermal spike models

  20. Electrical properties of gallium arsenide irradiated with electrons and neutrons

    International Nuclear Information System (INIS)

    Kol'chenko, T.I.; Lomako, V.M.

    1975-01-01

    A study was made of changes in the electrical properties of GaAs doped with Te, S, Se, Si, Ge, Sn (n 0 approximately 10 16 -10 18 cm -3 ) and irradiated either with 2.5-28 MeV electrons or with fast reactor neutrons. An analysis of changes in the electron density indicated that the rate of carrier removal by electron bombardment was independent of the dopant but was governed by isolated radiation defects. The change in the mobility due to irradiation with 2.5-10 MeV electrons was also governed by isolated defects. When the electron energy was increased to 28 MeV the main contribution to the change in the mobility was made by defect clusters. In the neutron-irradiation case the changes in the carrier density and mobility were mainly due to defect clusters and the nature of changes in the electrical properties was again independent of the dopant

  1. Electron irradiation effect on single crystal of niobium

    International Nuclear Information System (INIS)

    Otero, M.P.; Lucki, G.

    1984-01-01

    The effect of electron irradiation (900 KeV) on gliding dislocations of single crystal Nb with its tensile axe in the [941] orientation was observed for the in-situ deformation in a high voltage electron microscope (HVEM) at Argonne National Laboratory. The experimental was carried out by the 1 hour-electron irradiation with no stress applied. Straight dislocations actuating as sinks for the electron produced defects became helicoidal as the irradiation proceeded. Frenkel pairs were created in Nb for electron energies > = 650 KeV and, as the single vacancies do not undergo long-range migration in Nb at temperatures much below 620 K, the defects that are entrapped by the dislocations are self-interstitials produced by electron displacement. Applying the stress it was possible to observe that modified dislocations did not glide while the dislocations not affected by the irradiation are visibly in movement. This important result explains the neutron and electron-irradiation induced work-hardening effect for Nb that was previously observed. (Author) [pt

  2. The role of electron irradiation history in liquid cell transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Moser, Trevor H.; Mehta, Hardeep S.; Park, Chiwoo; Kelly, Ryan T.; Shokuhfar, Tolou; Evans, James E.

    2018-04-20

    In situ liquid cell transmission electron microscopy (LC-TEM) allows dynamic nanoscale characterization of systems in a hydrated state. Although powerful, this technique remains impaired by issues of repeatability that limit experimental fidelity and hinder the identification and control of some variables underlying observed dynamics. We detail new LC- TEM devices that improve experimental reproducibility by expanding available imaging area and providing a platform for investigating electron flux history on the sample. Irradiation history is an important factor influencing LC-TEM results that has, to this point, been largely qualitatively and not quantitatively described. We use these devices to highlight the role of cumulative electron flux history on samples from both nanoparticle growth and biological imaging experiments and demonstrate capture of time zero, low-dose images on beam-sensitive samples. In particular, the ability to capture pristine images of biological samples, where the acquired image is the first time that the cell experiences significant electron flux, allowed us to determine that nanoparticle movement compared to the cell membrane was a function of cell damage and therefore an artifact rather than visualizing cell dynamics in action. These results highlight just a subset of the new science that is accessible with LC-TEM through the new multiwindow devices with patterned focusing aides.

  3. A comparison of ionizing radiation damage in CMOS devices from 60Co gamma rays, electrons and protons

    International Nuclear Information System (INIS)

    He Baoping; Yao Zhibin; Zhang Fengqi

    2009-01-01

    Radiation hardened CC4007RH and non-radiation hardened CC4011 devices were irradiated using 60 Co gamma rays, 1 MeV electrons and 1-9 MeV protons to compare the ionizing radiation damage of the gamma rays with the charged particles. For all devices examined, with experimental uncertainty, the radiation induced threshold voltage shifts (ΔV th ) generated by 60 Co gamma rays are equal to that of 1 MeV electron and 1-7 MeV proton radiation under 0 gate bias condition. Under 5 V gate bias condition, the distinction of threshold voltage shifts (ΔV th ) generated by 60 Co gamma rays and 1 MeV electrons irradiation are not large, and the radiation damage for protons below 9 MeV is always less than that of 60 Co gamma rays. The lower energy the proton has, the less serious the radiation damage becomes. (authors)

  4. Irradiation effect of electronic beam on older larvae of Lasioderma serricorne (Fabricius)

    International Nuclear Information System (INIS)

    Chen Yuntang; Guo Dongquan; Zhang Jianwei; Yang Baoan

    2010-01-01

    Cigarette beetle [ Lasioderma serricorne (Fabricius) ] is an important pest of stored tobacco distributing over the world, and it is also one of the most serious pests in the tobacco warehouse. The larvae is the most serious detriment in the four states of cigarette beetle. The objective of this study was to control the damage on tobacco from cigarette beetle. The irradiation effects of electronic beam on the older larvae of cigarette beetle in tobacco were studied. The results showed that the older larvae irradiated by the doses higher than 480 Gy could prevent the development to adults; and no new generation was found after 300 Gy irradiation for older larvae. Thus 300Gy irradiation could prevent the reproduction of cigarette beetle for the older larvae in the tobacco. (authors)

  5. Electron microscope study of irradiated beryllium oxide

    International Nuclear Information System (INIS)

    Bisson, A.A.

    1965-06-01

    The beryllium oxide is studied first by fractography, before and after irradiation, using sintered samples. The fractures are examined under different aspects. The higher density sintered samples, with transgranular fractures are the most interesting for a microscopic study. It is possible to mark the difference between the 'pores' left by the sintering process and the 'bubbles' of gases that can be produced by former thermal treatments. After irradiation, the grain boundaries are very much weakened. By annealing, it is possible to observe the evolution of the gases produced by the reaction (n, 2n) and (n. α) and gathered on the grain boundaries. The irradiated beryllium oxide is afterwards studied by transmission. For that, a simple method has been used: little chips of the crushed material are examined. Clusters of point defects produced by neutrons are thus detected in crystals irradiated at the three following doses: 6 x 10 19 , 9 x 10 19 and 2 x 10 20 n f cm -2 at a temperature below 100 deg. C. For the irradiation at 6 x 10 19 n f cm -2 , the defects are merely visible, but at 2 x l0 20 n f cm -2 the crystals an crowded with clusters and the Kikuchi lines have disappeared from the micro-diffraction diagrams. The evolution of the clusters into dislocation loops is studied by a series of annealings. The activation energy (0,37 eV) calculated from the annealing curves suggests that it must be interstitials that condense into dislocation loops. Samples irradiated at high temperatures (650, 900 and 1100 deg. C) are also studied. In those specimens the size of the loops is not the same as the equilibrium size obtained after out of pile annealing at the same temperature. Those former loops are more specifically studied and their Burgers vector is determined by micro-diffraction. (author) [fr

  6. Irradiation damages in Ti3SiC2

    International Nuclear Information System (INIS)

    Nappe, J.C.; Grosseau, Ph.; Guilhot, B.; Audubert, F.; Beauvy, M.

    2007-01-01

    Carbides, by their remarkable properties, are considered as possible materials (fuel cans) in reactor of generation IV. Among those studied, Ti 3 SiC 2 is particularly considered because it joins both the ceramics and metals properties. Nevertheless, its behaviour under irradiation is not known. Characterizations have been carried out on samples irradiated at 75 MeV krypton ions. They have revealed that TiO 2 (formed at the surface of Ti 3 SiC 2 ) is pulverized by the irradiation and that the crystal lattice of Ti 3 SiC 2 dilates with c. (O.M.)

  7. Effect of foil orientation on damage accumulation during irradiation in magnesium and annealing response of dislocation loops

    International Nuclear Information System (INIS)

    Khan, A.K.; Yao, Z.; Daymond, M.R.; Holt, R.A.

    2012-01-01

    Highlights: ► Effect of foil orientation on electron irradiation damage in Mg is analyzed. ► Prism plane defects increases in prism foils as compared to basal foils. ► Basal faults were interstitial and prism plane defects were mixed in character. ► Shrinkage of interstitial dislocations takes place by the self diffusion mechanism. - Abstract: The effect of foil orientation on damage accumulation behavior in commercial purity magnesium is investigated by in situ electron and ion irradiation. Transmission electron microscope has been used to study the dislocation loops formed by the agglomeration of point defects during irradiation. It has been observed that the ratio of prism plane to basal plane defects increases as the foil orientation is changed from basal to the prism foil. The ratio of vacancy to interstitial defects also increases in prism foils as compared to the basal foils. This point defect accumulation behavior is reversed when magnesium is irradiated with 1 MeV Kr 2+ ions and the formation of basal plane dislocation loops were only observed in prism foils and did not take place in the basal foils. Analysis showed that all the basal plane dislocation loops have Burgers vector of the type 1/(6〈202 ¯ 3〉) and are interstitial in nature whereas prism plane dislocation loops have Burgers vector of the type 1/(3〈112 ¯ 0〉) and are of mixed interstitial/vacancy in character. In situ annealing experiments at different temperatures performed on electron irradiated magnesium foils suggest that those dislocation loops that become thermodynamically unstable anneal out in a matter of few seconds whereas other stable dislocation loops continue to shrink by absorbing surrounding vacancy clusters. The activation energy for the shrinkage of the interstitial dislocation loops has been derived and the results show that the shrinkage of interstitial dislocation loops takes place by the mechanism of vacancy assisted self diffusion.

  8. High dose radiation damage in nuclear energy structural materials investigated by heavy ion irradiation simulation

    International Nuclear Information System (INIS)

    Zheng Yongnan; Xu Yongjun; Yuan Daqing

    2014-01-01

    Structural materials in ITER, ADS and fast reactor suffer high dose irradiations of neutrons and/or protons, that leads to severe displacement damage up to lOO dpa per year. Investigation of radiation damage induced by such a high dose irradiation has attracted great attention along with the development of nuclear energy facilities of new generation. However, it is deeply hampered for the lacking of high dose neutron and proton sources. Irradiation simulation of heavy ions produced by accelerators opens up an effective way for laboratory investigation of high dose irradiation induced radiation damage encountered in the ITER, ADS, etc. Radiation damage is caused mainly by atomic displacement in materials. The displacement rate of heavy ions is about lO 3 ∼10 7 orders higher than those of neutrons and protons. High displacement rate of heavy ions significantly reduces the irradiation time. The heavy ion irradiation simulation technique (HIIS) technique has been developed at China Institute of Atomic Energy and a series of the HIIS experiments have been performed to investigate radiation damage in stainless steels, tungsten and tantalum at irradiation temperatures from room temperature to 800 ℃ and in the irradiation dose region up to 100 dpa. The experimental results show that he radiation swelling peak for the modified stainless steel appears in the temperature region around 580 ℃ and the radiation damage is more sensitive to the temperature, the size of the radiation induced vacancy cluster or void increase with the increasing of the irradiation dose, and among the three materials the home-made modified stainless steel has the best radiation resistant property. (authors)

  9. Analysis of Low Dose Irradiation Damages in Structural Ferritic/Martensitic Steels by Proton Irradiation and Nanoindentation

    International Nuclear Information System (INIS)

    Waseem, Owais A.; Ryu, Ho Jin; Park, Byong Guk; Jeong, Jong Ryul; Maeng, Cheol Soo; Lee, Myoung Goo

    2016-01-01

    As a result, ferritic-martensitic steels find applications in the in-core and out-of-core components which include ducts, piping, pressure vessel and cladding, etc. Due to ferromagnetism of F/M steel, it has been successfully employed in solenoid type fuel injector. Although the irradiation induced degradation in ferritic martensitic steels is lower as compare to (i) reduced activation steels, (ii) austenitic steels and (iii) martensitic steels, F/M steels are still prone to irradiation induced hardening and void swelling. The irradiation behavior may become more sophisticated due to transmutation and production of helium and hydrogen. The ductile to brittle transition temperature of F/M steels is also expected to increase due to irradiation. These irradiation induced degradations may deteriorate the integrity of F/M components. As a result of these investigations, it has found that the F/M steels experience no irradiation hardening above 400 .deg. C, but below this temperature, up to 350 .deg. C, weak hardening is observed. The irradiation hardening becomes more pronounced below 300 .deg. C. Moreover, the irradiation hardening has also found dependent upon radiation damage. The hardening was found increasing with increasing dose. Due to pronounced irradiation hardening below 300 .deg. C and increasing radiation damage with increasing dose (even at low dpa), it is required to investigate the post irradiation mechanical properties of F/M steel, in order to confirm its usefulness in structural and magnetic components which experience lifetime doses as low as 1x10"-"5 dpa.

  10. Analysis of Low Dose Irradiation Damages in Structural Ferritic/Martensitic Steels by Proton Irradiation and Nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Waseem, Owais A.; Ryu, Ho Jin; Park, Byong Guk [KAIST, Daejeon (Korea, Republic of); Jeong, Jong Ryul [Chungnam University, Daejeon (Korea, Republic of); Maeng, Cheol Soo; Lee, Myoung Goo [KEPCO, Daejeon (Korea, Republic of)

    2016-05-15

    As a result, ferritic-martensitic steels find applications in the in-core and out-of-core components which include ducts, piping, pressure vessel and cladding, etc. Due to ferromagnetism of F/M steel, it has been successfully employed in solenoid type fuel injector. Although the irradiation induced degradation in ferritic martensitic steels is lower as compare to (i) reduced activation steels, (ii) austenitic steels and (iii) martensitic steels, F/M steels are still prone to irradiation induced hardening and void swelling. The irradiation behavior may become more sophisticated due to transmutation and production of helium and hydrogen. The ductile to brittle transition temperature of F/M steels is also expected to increase due to irradiation. These irradiation induced degradations may deteriorate the integrity of F/M components. As a result of these investigations, it has found that the F/M steels experience no irradiation hardening above 400 .deg. C, but below this temperature, up to 350 .deg. C, weak hardening is observed. The irradiation hardening becomes more pronounced below 300 .deg. C. Moreover, the irradiation hardening has also found dependent upon radiation damage. The hardening was found increasing with increasing dose. Due to pronounced irradiation hardening below 300 .deg. C and increasing radiation damage with increasing dose (even at low dpa), it is required to investigate the post irradiation mechanical properties of F/M steel, in order to confirm its usefulness in structural and magnetic components which experience lifetime doses as low as 1x10{sup -5} dpa.

  11. Transmission electron microscope study of neutron irradiation-induced defects in silicon

    International Nuclear Information System (INIS)

    Oshima, Ryuichiro; Kawano, Tetsuya; Fujimoto, Ryoji

    1994-01-01

    Commercial Czochralski-grown silicon (Cz-Si) and float-zone silicon (Fz-Si) wafers were irradiated with fission neutrons at various fluences from 10 19 to 10 22 n/cm 2 at temperatures ranging from 473 K to 1043 K. The irradiation induced defect structures were examined by transmission electron microscopy and ultra high voltage electron microscopy, which were compared with Marlowe code computer simulation results. It was concluded that the vacancy-type damage structure formed at 473 K were initiated from collapse of vacancy-rich regions of cascades, while interstitial type defect clusters formed by irradiation above 673 K were associated with interstitial oxygen atoms and free interstitials which diffused out of the cascades. Complex defect structures were identified to consist of {113} and {111} planar faults by the parallel beam illumination diffraction analysis. (author)

  12. Ultrastructural changes following electron irradiation in three-dimensional culture of normal human dermal fibroblasts

    International Nuclear Information System (INIS)

    Han, Chunmao; Ishikura, Naotaka; Tsukada, Sadao

    1994-01-01

    The present study was designed to examine the effect of electron irradiation on fibroblasts and extracellular matrices electron-microscopically. The three-dimensional dermal fibroblast culture was exposed to one, 4 or 10 Gy of electron beams. One day after irradiation, fibroblasts were vacuolated in all irradiated groups and intercellular spaces were increased in a dose-dependent manner. Seven days later, intercellular spaces became dense in both one and 4 Gy groups, although they were still extremely increased in the 10 Gy group. The remaining fibroblasts were still activated in all groups. Thirty days after irradiation, myofibroblastic cells were scarcely observed, but extracellular fine fibrils and collagen fibrils were observed in all irradiated groups. The other ultrastructural findings were similar to those in the control group. In conclusion, electron beams damaged not only cells but also extracellular matrix. The extracellular matrix may be repaired by activated residual fibroblasts, resulting in the mixture of new and old collagen fibrils having different diamters. (N.K.)

  13. Paraelasticity in electron-irradiated molybdenum

    International Nuclear Information System (INIS)

    Beuneu, Brigitte; Quere, Yves.

    1981-11-01

    The relaxation of a radiation-induced point defect-most probably the rotation of a dumbell-is observed during isothermal anneals of irradiated molybdenum by resistivity measurements. The recovery of close pairs is not affected, in first analysis, by the presence of a uniaxial stress

  14. Radiation Damage Effects and Performance of Silicon Strip Detectors using LHC Readout Electronics

    CERN Document Server

    AUTHOR|(CDS)2067734

    1998-01-01

    Future high energy physics experiments as the ATLAS experiment at CERN, will use silicon strip detectors for fast and high precision tracking information. The high hadron fluences in these experiments cause permanent damage in the silicon.Additional energy levels are introduced in the bandgap thus changing the electrical properties such as leakage current and full depletion voltage V_fd .Very high leakage currents are observed after irradiation and lead to higher electronic noise and thus decrease the spatial resolution.V_fd increases to a few hundred volts after irradiation and eventually beyond the point of stable operating voltages. Prototype detectors with either p-implanted strips (p-in-n) and n-implanted strip detectors (n-in-n) were irradiated to the maximum expected fluence in ATLAS.The irradiation and the following study of the current and V_fd were carried out under ATLAS operational conditions.The evolution of V_fd after irradiation is compared to models based on diode irradiations.The qualitative ...

  15. Repair of membrane damage in X-irradiated E. coli

    International Nuclear Information System (INIS)

    Gillies, N.E.; Ratnajothi, N.H.; Hewamanna, R.; Obioha, F.I.

    1984-01-01

    When E. coli B/r or E. coli K12 AB1157 were X-irradiated in the presence of oxygen and incubated immediately after irradiation in broth containing penicillin in concentration that on its own was not lethal to unirradiated bacteria, substantial additional killing was caused. When treatment with penicillin was delayed for increasing times after irradiation the additional killing became progressively less. These results were interpreted as demonstrating the repair or removal of oxygen-dependent radiation-induced lesions in the bacterial membranes. Removal of these lesions was inhibited by incubation of the irradiated bacteria at low temperature before treatment with penicillin or by exposing the cells to a non-lethal concentration of toluene before irradiation. These observations suggest that an enzymatic repair process may be involved in the removal of the membrane lesions. The fatty acid mutant E. coli K 1060 proved exceptional in that some additional killing by penicillin was detectable after anaerobic as well as aerobic irradiation. This points to the importance of membrane composition in the development of those radiation lesions that are brought to light by penicillin treatment. (author)

  16. Estimation of γ irradiation induced genetic damage by Ames test

    International Nuclear Information System (INIS)

    Hosoda, Eiko

    1999-01-01

    Mutation by 60 Co γ irradiation was studied in five different histidine-requiring auxotrophs of Salmonella typhimurium. The strains TA98 (sensitive to frameshift) and TA100 (sensitive to base-pair substitution) were irradiated (10-84 Gy and 45-317 Gy, respectively) and revertants were counted. TA98 exhibited radiation-induced revertants, 2.8 fold of spontaneous revertants, although no significant increase was detected in TA100. Then, three other frameshift-sensitive strains TA1537, TA1538 and TA94 were irradiated in a dose of 61-167 Gy. Only in TA94, revertants increased 3.5 fold. Since spontaneous revertants are known to be independent of cell density, a decrease of bacterial number by γ irradiation was confirmed not to affect the induced revertants by dilution test. Thus the standard Ames Salmonella assay identified γ irradiation was confirmed not to affect the induced revertants by dilution test. Thus the standard Ames Salmonella assay identified γ irradiation as a mutagenetic agent. The mutagenicity of dinitropyrene, a mutagen widely existing in food, and dismutagenicity of boiling water insoluble fraction of Hizikia fusiforme, edible marine alga, were tested on γ induced revertant formation in TA98 and TA94. Dinitropyrene synergistically increased γ induced revertants and Hizikia insoluble fraction reduced the synergistic effect of dinitropyrene dependently on the concentration. (author)

  17. Electron irradiation experiments in support of fusion materials development

    International Nuclear Information System (INIS)

    Gelles, D.S.; Ohnuki, S.; Takahashi, H.; Matsui, H.; Kohno, Y.

    1991-11-01

    Microstructural evolution in response to 1 MeV irradiation has been investigated for three simple ferritic alloys, pure beryllium, pure vanadium, and two simple vanadium alloys over a range of temperatures and doses. Microstructural evolution in Fe-3, -9, and -18Cr ferritic alloys is found to consist of crenulated, faulted a loops and circular, unfaulted a/2 loops at low temperatures, but with only unfaulted loops at high temperatures. The complex dislocation evolution is attributed to sigma phase precipifaults arising from chromium segregation to point defect sinks. Beryllium is found to be resistant to electron damage; the only effect observed was enhanced dislocation mobility. Pure vanadium, V-5Fe, and V-1Ni microstructural response was complicated by precipitation on heating to 400 degrees C and above, but dislocation evolution was investigated in the range of room temperature to 300 degrees C and at 600 degrees C. The three materials behaved similarly, except that pure vanadium showed more rapid dislocation evolution. This difference does not explain the enhanced swelling observed in vanadium alloys

  18. Polymerization of vinyl stearate multilayers by electron beam irradiation

    International Nuclear Information System (INIS)

    Nishii, Masanobu; Hatada, Motoyoshi

    1975-01-01

    Studies on the radiation-induced polymerization of vinyl stearate (VST) multilayers were carried out. The VST multilayers built-up on an aluminum plated glass plate by Langmuir-Blodgett technique were irradiated with electron beams from a Van de Graaff electron accelerator in nitrogen atmosphere. The structure of the multilayers and the effects of irradiation were investigated by X-ray diffractometry, contact angle measurement, multireflection infrared spectroscopy, and scanning electron microscopy. The VST multilayers became insoluble to methanol by the irradiation, and the multi-reflection infrared spectrum of the VST multilayers turned into that of poly (VST) with increasing dosage. The polymerization proceeded during the irradiation at the temperature range between -10 0 and 10 0 C, and the conversion attained to 90% within 2.5 minutes (total dose, 5.6 Mrads). The multilayers irradiated above 13 Mrads turned into the polymer film insoluble to benzene, indicating that the polymer chains were cross-linked by the irradiation. Stearic acid which was formed by the irradiation of VST at nitrogen-water interface as a hydrolysis product was not detected in this system. (auth.)

  19. Postharvest quality of cut roses following electron-beam irradiation

    International Nuclear Information System (INIS)

    Chang, A.Y.; Gladon, R.J.; Gleason, M.L.; Parker, S.K.; Agnew, N.H.; Olson, D.G.

    1997-01-01

    Cut Rosa x hybrida L. 'Royalty' flowers were used to determine the efficacy of electron-beam irradiation for increasing postharvest quality and decreasing petal infection by Botrytis cinerea Pers. In an experiment for determining the injury threshold, roses received electron-beam irradiation of 0, 0.5, 1, 2, and 4 kGy. Irradiation dosages greater than or equal to 4 kGy caused necrosis on petal tissue and decreased postharvest life at 20 degrees C. In a second experiment to evaluate postharvest quality, roses were irradiated at 0, 0.25, 0.5, 0.75, and 1 kGy. Dosages of 0.25 and 0.5 kGy slowed the rate of flower bud opening for 2 days but did not decrease postharvest quality when compared with nonirradiated roses. Roses that received irradiation dosages of 0.75 and 1 kGy showed unacceptable quality. In a third experiment, roses that had or had not been inoculated with B. cinerea were irradiated at 0, 0.25, 0.5, and 0.75 kGy. Irradiation did not control B. cinerea populations, and rose quality decreased as dosage increased. In a fourth experiment to determine the effect of irradiation on B. cinerea, conidia on water-agar plates exposed to dosages less than or equal to 1, 2, and 4 kGy germinated at rates of approximately 90%, 33%, and 2%, respectively, within 24 h

  20. Preparation of PbSe nanoparticles by electron beam irradiation

    Indian Academy of Sciences (India)

    A novel method has been developed by electron beam irradiation to prepare PbSe nanoparticles. 2 MeV 10mA GJ-2-II electronic accelerator was used as radiation source. Nanocrystalline PbSe was prepared rapidly at room temperature under atmospheric pressure without any kind of toxic reagents. The structure and ...

  1. Silver nanoparticles: synthesis and size control by electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Bogle, K A; Dhole, S D; Bhoraskar, V N [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Pune-411007 (India)

    2006-07-14

    Silver nanoparticles were synthesized by irradiating solutions, prepared by mixing AgNO{sub 3} and poly-vinyl alcohol (PVA), with 6 MeV electrons. The electron-irradiated solutions and the thin coatings cast from them were characterized using the ultraviolet-visible (UV-vis), x-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques. During electron irradiation, the process of formation of the silver nanoparticles appeared to be initiated at an electron fluence of {approx}2 x 10{sup 13} e cm{sup -2}. This was evidenced from the solution, which turned yellow and exhibited the characteristic plasmon absorption peak around 455 nm. Silver nanoparticles of different sizes in the range 60-10 nm, with a narrow size distribution, could be synthesized by varying the electron fluence from 2 x 10{sup 13} to 3 x 10{sup 15} e cm{sup -2}. Silver nanoparticles of sizes in the range 100-200 nm were also synthesized by irradiating an aqueous AgNO{sub 3} solution with 6 MeV electrons.

  2. A comparative study on the effects of electron beam irradiation on imidacloprid-resistant and -susceptible Aphis gossypii (Hemiptera: Aphididae)

    Science.gov (United States)

    Yun, Seung-Hwan; Koo, Hyun-Na; Lee, Seon-Woo; Kim, Hyun Kyung; Kim, Yuri; Han, Bumsoo; Kim, Gil-Hah

    2015-07-01

    The melon and cotton aphid, Aphis gossypii, is a polyphagous insect pest. This study compared the development, reproduction, DNA damage, recovery, and gene expression in imidacloprid-resistant (IMI-R) and -susceptible (S) strains of A. gossypii by electron beam irradiation. When 1st instar nymphs were irradiated with 100 Gy, the fecundity (nymphs of F1 generation) of the resultant adults were completely inhibited. When adults were irradiated with 200 Gy, the number of total 1st instar nymphs produced per adult was 3.0±1.7 and 1.9±1.4 in the S and IMI-R strains, respectively, but adult development was completely suppressed. However, electron beam irradiation did not affect adult longevity in either the S or IMI-R strain. There was no statistically significant difference between the effect of irradiation on the S and IMI-R strains. Therefore, electron beam irradiation at 200 Gy could be used as a phytosanitary irradiation treatment for both S and IMI-R strains of A. gossypii. The DNA damage caused by electron beam irradiation was evaluated by an alkaline comet assay. Exposure to an electron beam (50 Gy) induced DNA damage that was repaired to a similar level as the untreated control group (0 Gy) over time. However, at more than 100 Gy, the DNA damage was not completely repaired. The expression of P450, HSP70, cuticle protein, and elongation factor genes were higher in the IMI-R strain than in the S strain.

  3. Irradiation damages of semiconductor devices and their improvement

    Energy Technology Data Exchange (ETDEWEB)

    Uwatoko, Yoshiya [Saitama Univ., Urawa (Japan); Ohyama, Hidenori; Hayama, Kiyoteru; Hakata, Tetsuya; Kudou, Tomohiro

    1998-01-01

    In this study, effect of radiation on semiconductor devices was evaluated at both sides of electrical and crystalline properties for two years from 1995 fiscal years. And, damage of Si(sub 1-x)Ge(sub x) device was considered at viewpoints of Ge content and sprung-out atomic number and non ionization energy loss of constituting atom formed by radiation on its radiation source dependency of damage. This paper was a report on proton beam damage of the Si(sub 1-x)Ge(sub x) device, neutron damage of InGaAs photodiode, and effect of Ga content and kinds of beam on their damages. (G.K.)

  4. Field-ion microscope studies of the defect structure of the primary state of damage of irradiated metals

    International Nuclear Information System (INIS)

    Seidman, D.N.

    1975-01-01

    A review is presented of field ion microscope applications in studies of point defect distribution in irradiated metals. FIM results on the primary state of radiation damage in neutron and ion-irradiated iridium and tungsten, at both room-temperature and 78 0 K, showed that it consists of: (1) isolated vacancies; (2) depleted zones; (3) compact vacancy clusters of voids; and (4) dislocation loops. The fraction of vacancies stored in the dislocation loops represented a small fraction of the total vacancy concentration; in the case of tungsten it was approximately 10 percent. These FIM observations provide a simple explanation of the low yield-factor, determined by transmission electron microscopy, for a number of ion-irradiated metals

  5. Radiation defects in electron-irradiated InP crystals

    International Nuclear Information System (INIS)

    Brailovskii, E.Yu.; Karapetyan, F.K.; Megela, I.G.; Tartachnik, V.P.

    1982-01-01

    The results are presented of formation and annealing of defects in InP crystals at 1 to 50 MeV electron irradiation. The recovery of electrical properties in the range of 77 to 970 K during annealing processes is studied. Five low temperature annealing states in n-InP and the reverse annealing in p-InP are observed at 77 to 300 K. Four annealing stages at temperatures higher than 300 K are present. When the electron energy is increased more complicated thermostable defects are formed, and at 50 MeV electron energy besides of the point defect clusters are formed, which anneal at temperatures of 800 to 970 K. It is shown that the peculiarities of the Hall mobility at irradiation and annealing are caused by the scattering centres E/sub c/ - 0.2 eV. The 'limiting' position of the Fermi level in electron irradiated InP crystals is discussed. (author)

  6. 'The future of the electron beam irradiation service business'

    International Nuclear Information System (INIS)

    Yamase, Yutaka

    1998-01-01

    The high energy electron beam has less penetration power in comparison with the gamma ray which has been used from before. However, the dose rate of the electron beam is considerably high in comparison with the gamma ray with more than several thousand times. Therefore, the irradiation of the product can be done in a short time, and there are cheap characteristics further in the irradiation cost as well. And, an electron beam is the technology which is very easy to accept in the country of a nuclear allergy constitution like our country so that it may not use radioactive substance. This time, I'd like to think about the present condition of the electron beam irradiation service business and a future based on the experience of Tsukuba EBcenter until now. (J.P.N.)

  7. An evaluation of the effects of epidermal growth factor on irradiation lip mucosa damage in mice

    International Nuclear Information System (INIS)

    Feng Yan

    1994-01-01

    The effect of epidermal growth factor (EGF) on lip mucosa damage by irradiation was explored in mice. EGF was administered in doses of 100 μg/kg/day using different schedules. Mucosal damage was assessed. The metaphase arrest method with vinblastine was used to evaluate the diurnal rhythm of mitosis. EGF in regimens employed did not protect the mouse lip epithelial cells from irradiation induced damage, but it has a demonstrable stimulatory effect on cell proliferation in lip mucosa which is dependent on the schedules of administration. The reasons and mechanisms are discussed

  8. Electron beam dosimetry for a thin-layer absorber irradiated by 300-keV electrons

    International Nuclear Information System (INIS)

    Kijima, Toshiyuki; Nakase, Yoshiaki

    1993-01-01

    Depth-dose distributions in thin-layer absorbers were measured for 300-keV electrons from a scanning-type irradiation system, the electrons having penetrated through a Ti-window and an air gap. Irradiations of stacks of cellulose triacetate(CTA) film were carried out using either a conveyor (i.e. dynamic irradiation) or fixed (i.e. static) irradiation. The sample was irradiated using various angles of incidence of electrons, in order to examine the effect of obliqueness of electron incidence at low-energy representative of routine radiation curing of thin polymeric or resin layers. Dynamic irradiation gives broader and shallower depth-dose distributions than static irradiation. Greater obliqueness of incident electrons gives results that can be explained in terms of broader and shallower depth-dose distributions. The back-scattering of incident electrons by a metal(Sn) backing material enhances the absorbed dose in a polymeric layer and changes the overall distribution. It is suggested that any theoretical estimations of the absorbed dose in thin layers irradiated in electron beam curing must be accomplished and supported by experimental data such as that provided by this investigation. (Author)

  9. Edaravone protects human peripheral blood lymphocytes from γ-irradiation-induced apoptosis and DNA damage.

    Science.gov (United States)

    Chen, Liming; Liu, Yinghui; Dong, Liangliang; Chu, Xiaoxia

    2015-03-01

    Radiation-induced cellular injury is attributed primarily to the harmful effects of free radicals, which play a key role in irradiation-induced apoptosis. In this study, we investigated the radioprotective efficacy of edaravone, a licensed clinical drug and a powerful free radical scavenger that has been tested against γ-irradiation-induced cellular damage in cultured human peripheral blood lymphocytes in studies of various diseases. Edaravone was pre-incubated with lymphocytes for 2 h prior to γ-irradiation. It was found that pretreatment with edaravone increased cell viability and inhibited generation of γ-radiation-induced reactive oxygen species (ROS) in lymphocytes exposed to 3 Gy γ-radiation. In addition, γ-radiation decreased antioxidant enzymatic activity, such as superoxide dismutase and glutathione peroxidase, as well as the level of reduced glutathione. Conversely, treatment with 100 μM edaravone prior to irradiation improved antioxidant enzyme activity and increased reduced glutathione levels in irradiated lymphocytes. Importantly, we also report that edaravone reduced γ-irradiation-induced apoptosis through downregulation of Bax, upregulation of Bcl-2, and consequent reduction of the Bax:Bcl-2 ratio. The current study shows edaravone to be an effective radioprotector against γ-irradiation-induced cellular damage in lymphocytes in vitro. Finally, edaravone pretreatment significantly reduced DNA damage in γ-irradiated lymphocytes, as measured by comet assay (% tail DNA, tail length, tail moment, and olive tail moment) (p edaravone offers protection from radiation-induced cytogenetic alterations.

  10. Damage of chromosoms under irradiation of human blood lymphocytes and development of bystander effect.

    Science.gov (United States)

    Shemetun, O V

    2016-12-01

    the research the distribution of radiation induced damages among chromosomes and their bands in irra diated in vitro human blood lymphocytes and in unirradiated bystander cells.Material and methods of research: cultivation of human peripheral blood lymphocytes by semi micromethod D.A. Hungerford, modeling of radiation induced bystander effect in mixed cultures consisting of irradiated in vitro and non irradiated blood lymphocytes from persons of different gender, GTG staining of metaphase chromosomes and their cytogenetic analysis. Break points in chromosomes under the formation of aberrations were identified in exposed in vitro human peripheral blood lymphocytes in doses 0.25 Gy (95 breaks in 1248 cells) and 1.0 Gy (227 breaks in 726 cells) and in non irradiated bystander cells under their joint cultivation with irradiated in vitro human lymphocytes (51 breaks in 1137 cells at irradiation of adjacent populations of lymphocytes in dose 0.25 Gy and 75 breaks in 1321 cells at irradiation of adjacent population of lymphocytes in a dose 1.0 Gy). The distribution of injuries among the chromo somes and their bands was investigated. in radiation exposed in vitro human peripheral blood lymphocytes as well as in bystander cells the fre quency of damaged bands and number of breaks which localized in them exceeded the control value (p chromosomes were damaged according to their relative length. Location of bands with increasing number of breaks coincided with the «hot spots» of chromosome damage following irradiation and fragile sites. More sensitive to damage were G negative euchromatin chromosome bands, in which were localized 82 88 % breaks. Damageability of telomeric regions in the irradiated cells had no significant difference from the control, while in bystander cells was lower than control value (p < 0.05). O. V. Shemetun.

  11. DNA damage in synchronized hela cells irradiated with ultraviolet

    International Nuclear Information System (INIS)

    Downes, C.S.; Collins, A.R.S.; Johnson, R.T.

    1979-01-01

    The lethal effect of uv radiation on HeLa cells is least in mitosis and greatest in late G 1 -early S. Photochemical damage to HeLa DNA, as measured by thymine-containing dimer formation and by alkaline sucrose sedimentation, also increases from mitosis towards early S phase. Computer simulations of uv absorption by an idealized HeLa cell at different stages of the cell cycle indicate that changes in damage could be due solely to changes in chromatin geometry. But survival is not exclusively a function of damage

  12. DAMAGE IN MOLYBDENUM ASSOCIATED WITH NEUTRON IRRADIATION AND SUBSEQUENT POST-IRRADIATION ANNEALING

    Energy Technology Data Exchange (ETDEWEB)

    Mastel, B.

    1963-07-23

    Molybdemum containing carbon was studied in an attempt to establish the combined effect of impurity content and neutron irradiation on the properties and structure of specific metals. Molybdenum foils were punched into discs and heat treated in vacuum. They were then slow-cooled and irradiated. After irradiation and subsequent decay of radioactivity to a low level the foils were subjected to x-ray diffraction measurements. Cold-worked foils with less than 10 ppm carbon showed no change in microstructure due to irradiation. Molybdenum foils that were annealed prior to irradiation showed spot defects. In foils containing up to 500 ppm carbon, it was concluded that the small loops present after irradiation are due to the clustering of point defects at interstitial carbon atoms, followed by collapse to form a dislocation loop. The amount of lattice expansion after irradiation was strongly dependent on impurity content. Neutron irradiation was found to reduce the number of active slip systems. (M.C.G.)

  13. Electron Beam Induced Radiation Damage of the Semiconductor Radiation Detector based on Silicon

    International Nuclear Information System (INIS)

    Kim, Han Soo; Kim, Yong Kyun; Park, Se Hwan; Haa, Jang Ho; Kang, Sang Mook; Chung, Chong Eun; Cho, Seung Yeon; Park, Ji Hyun; Yoon, Tae Hyung

    2005-01-01

    A Silicon Surface Barrier (SSB) semiconductor detector which is generally used to detect a charged particle such as an alpha particle was developed. The performance of the developed SSB semiconductor detector was measured with an I-V curve and an alpha spectrum. The response for an alpha particle was measured by Pu-238 sources. A SSB semiconductor detector was irradiated firstly at 30sec, at 30μA and secondly 40sec, 40μA with a 2MeV pulsed electron beam generator in KAERI. And the electron beam induced radiation damage of a homemade SSB detector and the commercially available PIN photodiode were investigated. An annealing effect of the damaged SSB and PIN diode detector were also investigated using a Rapid Thermal Annealing (RTA). This data may assist in designing the silicon based semiconductor radiation detector when it is operated in a high radiation field such as space or a nuclear power plant

  14. Behaviour of some fresh fruits under electron-beam irradiation

    International Nuclear Information System (INIS)

    Ferdes, O.; Stroia, A.L.; Potcoava, A.; Cojocaru, M.; Mihnea, R.; Oproiu, C.

    1994-01-01

    The use of ionizing radiation in preservation of fruits and vegetables is widely recognized. In this paper it is presented a study of the effect of electron-beam irradiation of some fresh, early and perishable fruits, like strawberries, cherries, and sour cherries concerning their shelf-life time extension. The irradiations were performed on common varieties in normal conditions to the IPTRD's electron-beam accelerator (Bucharest-Magurele) having the following parameters: flow current 10 μA, power 60 W and electron mean energy 6.23 MeV. The irradiation doses varied between 0.5-3.0 kGy and the dose rates between 100-1500 Gy/min. It was observed the fruit preservation capability of the treatment and it was analysed the main characteristics as organoleptic properties, weight of dry component, acidity, total and reducing sugars, ascorbic acid content and others. It was evidenced an increase in freshness and shelf-life extension by 5-7 days for strawberries and up to two weeks for cherries without any significant changes in the values of the considered parameters. Otherwise, for the applied doses, the electron-beam irradiation did not produce any significant changes in the values of fruit characteristic parameters. The results lead to the conclusion that the electron-beam irradiation is a good technological solution for fresh fruit processing. (Author) 1 Tab., 7 Refs

  15. Electron beam irradiation of gemstone for color enhancement

    Science.gov (United States)

    Idris, Sarada; Ghazali, Zulkafli; Hashim, Siti A'iasah; Ahmad, Shamshad; Jusoh, Mohd Suhaimi

    2012-09-01

    Numerous treatment of gemstones has been going on for hundreds of years for enhancing color and clarity of gems devoid of these attributes. Whereas previous practices included fraudulent or otherwise processes to achieve the color enhancement, the ionizing radiation has proven to be a reliable and reproducible technique. Three types of irradiation processes include exposure to gamma radiation, electron beam irradiation and the nuclear power plants. Electron Beam Irradiation of Gemstone is a technique in which a gemstone is exposed to highly ionizing radiation electron beam to knock off electrons to generate color centers culminating in introduction of deeper colors. The color centers may be stable or unstable. Below 9MeV, normally no radioactivity is introduced in the exposed gems. A study was conducted at Electron Beam Irradiation Centre (Alurtron) for gemstone color enhancement by using different kind of precious gemstones obtained from Pakistan. The study shows that EB irradiation not only enhances the color but can also improves the clarity of some type of gemstones. The treated stones included kunzite, tourmaline, topaz, quartz, aquamarine and cultured pearls. Doses ranging from 25 kGy to 200 KGy were employed to assess the influence of doses on color and clarity and to select the optimum doses. The samples used included both the natural and the faceted gemstones. It is concluded that significant revenue generation is associated with the enhancement of the color in clarity of gemstones which are available at very cheap price in the world market.

  16. Electron beam irradiation of gemstone for color enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Idris, Sarada; Ghazali, Zulkafli; Hashim, Siti A' iasah; Ahmad, Shamshad; Jusoh, Mohd Suhaimi [Malaysian Nuclear Agency, Bangi, Selangor (Malaysia); School of Chemicals and Material Engineering, NUST Islamabad (Pakistan); Malaysian Nuclear Agency, Bangi, Selangor (Malaysia)

    2012-09-26

    Numerous treatment of gemstones has been going on for hundreds of years for enhancing color and clarity of gems devoid of these attributes. Whereas previous practices included fraudulent or otherwise processes to achieve the color enhancement, the ionizing radiation has proven to be a reliable and reproducible technique. Three types of irradiation processes include exposure to gamma radiation, electron beam irradiation and the nuclear power plants. Electron Beam Irradiation of Gemstone is a technique in which a gemstone is exposed to highly ionizing radiation electron beam to knock off electrons to generate color centers culminating in introduction of deeper colors. The color centers may be stable or unstable. Below 9MeV, normally no radioactivity is introduced in the exposed gems. A study was conducted at Electron Beam Irradiation Centre (Alurtron) for gemstone color enhancement by using different kind of precious gemstones obtained from Pakistan. The study shows that EB irradiation not only enhances the color but can also improves the clarity of some type of gemstones. The treated stones included kunzite, tourmaline, topaz, quartz, aquamarine and cultured pearls. Doses ranging from 25 kGy to 200 KGy were employed to assess the influence of doses on color and clarity and to select the optimum doses. The samples used included both the natural and the faceted gemstones. It is concluded that significant revenue generation is associated with the enhancement of the color in clarity of gemstones which are available at very cheap price in the world market.

  17. Electron beam irradiation of gemstone for color enhancement

    International Nuclear Information System (INIS)

    Idris, Sarada; Ghazali, Zulkafli; Hashim, Siti A'iasah; Ahmad, Shamshad; Jusoh, Mohd Suhaimi

    2012-01-01

    Numerous treatment of gemstones has been going on for hundreds of years for enhancing color and clarity of gems devoid of these attributes. Whereas previous practices included fraudulent or otherwise processes to achieve the color enhancement, the ionizing radiation has proven to be a reliable and reproducible technique. Three types of irradiation processes include exposure to gamma radiation, electron beam irradiation and the nuclear power plants. Electron Beam Irradiation of Gemstone is a technique in which a gemstone is exposed to highly ionizing radiation electron beam to knock off electrons to generate color centers culminating in introduction of deeper colors. The color centers may be stable or unstable. Below 9MeV, normally no radioactivity is introduced in the exposed gems. A study was conducted at Electron Beam Irradiation Centre (Alurtron) for gemstone color enhancement by using different kind of precious gemstones obtained from Pakistan. The study shows that EB irradiation not only enhances the color but can also improves the clarity of some type of gemstones. The treated stones included kunzite, tourmaline, topaz, quartz, aquamarine and cultured pearls. Doses ranging from 25 kGy to 200 KGy were employed to assess the influence of doses on color and clarity and to select the optimum doses. The samples used included both the natural and the faceted gemstones. It is concluded that significant revenue generation is associated with the enhancement of the color in clarity of gemstones which are available at very cheap price in the world market.

  18. Bulk and interface defects in electron irradiated InP

    International Nuclear Information System (INIS)

    Peng Chen; Sun Heng-hui

    1989-01-01

    Systematic studies on the structure of defects in InP caused by electron irradiation are conducted based on experimental measurements and theoretical calculations. The rates of introduction and annealing-out temperatures of In and P vancancies are estimated using proper theoretical models. These calculations reveal that after room temperature irradiation only complexes may exist. It is also supported by our experimental data that the sum of introducing rates of three detected levels are less than the theoretical value calculated for single vacancies. According to our equation on the relation between interface states and DLTS signal and from the results of computer calculation we believe that the broad peak appearing in the DLTS diagram before irradiation is related to interface states. Its disappearance after electron irradiation suggests the reduction of interface states; this is further confirmed by the reduction of surface recombination rate derived from the results of surface photovoltage measurement

  19. Manufacture of electron beam irradiation vessel and its characteristics

    International Nuclear Information System (INIS)

    Kanazawa, Takao; Haruyama, Yasuyuki; Yotsumoto, Keiichi

    1992-05-01

    Electron beam irradiation vessel, which is used for the irradiation of samples under an inert or a vacuum atmosphere, is made by considering the temperature control during or after irradiation. The vessel was composed of the temperature controlable samples supporting plate, beam slit with water cooling plate and the insert of thermosensor. The four samples supporting plate was produced with the materials made up of aluminium, stainless steel (SUS304), and copper. The stainless steel supporting plate has a heater inside the cooling pipes for the high temperature treatment of samples without exposure to atmosphere after the irradiation. In this report, the temperature distribution and dose characteristics such as dose distribution and effects of backscattered electron were studied by using several supporting plate and the comparison of the experimental results with the simulated results was also carried out. (author)

  20. Analytical electron microscopy of neutron-irradiated reactor alloys

    International Nuclear Information System (INIS)

    Thomas, L.E.

    1982-01-01

    Exposure to the high neutron fluxes and temperatures from 400 to 650 0 C in the core region of a fast breeder reactor profoundly alters the microstructure and properties of structural steels and superalloys. The development of irradiation-induced voids, dislocations and precipitates, as well as segregation of alloying elements on a microscopic scale has been related to macroscopic swelling, creep, hardening and embrittlement which occur during prolonged exposures in reactor. Microanalytical studies using TEM/STEM methods, primarily energy dispersive x-ray (EDX) microanalysis, have greatly aided understanding of alloy behavior under irradiation. The main uses of analytical electron microscopy in studying irradiated alloys have been the identification of irradiation-induced precipitates and determination of the changes in local composition due to irradiation-induced solute segregation

  1. Electron beam irradiation effect on nanostructured molecular sieve catalysts

    International Nuclear Information System (INIS)

    Yuan Zhongyong; Zhou Wuzong; Parvulescu, Viorica; Su Baolian

    2003-01-01

    Electron impact can induce chemical changes on particle surfaces of zeolites and molecular sieve catalysts. Some experimental observations of electron irradiation effect on molecular sieve catalysts are presented, e.g., electron-beam-induced growth of bare silver nanowires from zeolite crystallites, formation of vesicles in calcium phosphate, migration of microdomains in iron-oxide doped mesoporous silicas, structural transformation from mesostructured MCM-41 to microporous ZSM-5, etc. The formation mechanisms of the surface structures are discussed

  2. Clarification of leachate from reclaimed ground by electron beam irradiation

    International Nuclear Information System (INIS)

    Yamazaki, Masao; Sawai, Teruko; Shimokawa, Toshinari; Sawai, Takeshi

    1985-01-01

    To decompose organic matters such as humic acid and fulvous acid in the leachate from reclaimed ground, an electron beam irradiation technique was examined because of availability of higher dose rate than a 60 Co γ-ray source. This paper describes results of the above-mentioned preliminary examination. Test water was collected from No.15 dumping site at the Tokyo Bay. Irradiation sample was prepared by filtration with a filter and decarbonation with sulfuric acid. Fulvous acid solution by eliminating humic acid was also served for the examination. Electron beam irradiation of the sample solution was made with a Van de Graaf accelerator by 1.5 MeV, 140 Gy/sec of irradiation condition and with a dynamitron by 2.0 MeV, 25 kGy/pass of the condition. It was clarified that oxygen bubbling velocity during the irradiation did not affect much for the decrease rate of total organic matters (TOC) within 0.5 to 3.0 1/min of an experimental condition. As for radiation doses and TOC decrease, TOC was decreased much for lower dose rate irradiation (Van de Graaf accelerator), lower initial TOC concentration, or addition of hydrogen peroxide. For the combined treatment of radiation and flocculation to aim at irradiation dose decrease, fulvous acid solution was served for the test. Lower dose irradiation with a 60 Co source showed better TOC elimination and it was concluded that combination with flocculation was effective for the dose reduction. It was also found experimentally that TOC decrease behavior by the both radiation source was different due to temperature effect and further study should be made for the development of the practical electron beam irradiation technique. (Takagi, S.)

  3. Tumor induction and hair follicle damage for different electron penetrations in rat skin

    International Nuclear Information System (INIS)

    Burns, F.J.; Sinclair, I.P.; Albert, R.E.; Vanderlaan, M.

    1976-01-01

    The penetration and dose of an electron beam were varied in an attempt to locate the depth in growing-phase rat skin where irradiation was most effective in inducing tumors and morphological damage to the hair follicles. The hair was plucked to initiate the growing phase of the hair cycle, and 12 days later the dorsal skin was irradiated with electrons penetrating 0.5, 1.0, or 2.0 mm at doses from 500 to 4000 rad. Differences in the curves of tumor incidence as a function of dose for different penetrations were best resolved by plotting the results against the 0.4 mm dose, while comparable curves for destruction of the follicles were best resolved by the 0.8 mm dose. Since 0.8 mm corresponded approximately to the depth of the follicles, these results indicated that the target tissues for follicular damage and tumor induction were separated in depth and that the target for tumor induction was probably located in the region above or near the midpoint of the follicles. When the radiation penetrated sufficiently to reach the entire follicle, the number of tumors produced was not significantly greater than the number observed previously in resting-phase skin, and it was inferred that the additional size and greater mitotic activity of the growing-phase follicles at the time of irradiation did not increase the probability of tumor induction

  4. Surface damages of polycrystalline W and La2O3-doped W induced by high-flux He plasma irradiation

    Science.gov (United States)

    Liu, Lu; Li, Shouzhe; Liu, Dongping; Benstetter, Günther; Zhang, Yang; Hong, Yi; Fan, Hongyu; Ni, Weiyuan; Yang, Qi; Wu, Yunfeng; Bi, Zhenhua

    2018-04-01

    In this study, polycrystalline tungsten (W) and three oxide dispersed strengthened W with 0.1 vol %, 1.0 vol % and 5.0 vol % lanthanum trioxide (La2O3) were irradiated with low-energy (200 eV) and high-flux (5.8 × 1021 or 1.4 × 1022 ions/m2ṡs) He+ ions at elevated temperature. After He+ irradiation at a fluence of 3.0 × 1025/m2, their surface damages were observed by scanning electron microscopy, energy dispersive spectroscopy, scanning electron microscopy-electron backscatter diffraction, and conductive atomic force microscopy. Micron-sized holes were formed on the surface of W alloys after He+ irradiation at 1100 K. Analysis shows that the La2O3 grains doped in W were sputtered preferentially by the high-flux He+ ions when compared with the W grains. For irradiation at 1550 K, W nano-fuzz was formed at the surfaces of both polycrystalline W and La2O3-doped W. The thickness of the fuzz layers formed at the surface of La2O3-doped W is 40% lower than the one of polycrystalline W. The presence of La2O3 could suppress the diffusion and coalescence of He atoms inside W, which plays an important role in the growth of nanostructures fuzz.

  5. Damage in solids irradiated by a single shot of XUV free-electron laser: irreversible changes investigated using X-ray microdiffraction, atomic force microscopy and Nomarski optical microscopy

    Czech Academy of Sciences Publication Activity Database

    Pelka, J. B.; Sobierajski, R.; Klinger, D.; Paszkowicz, W.; Krzywinski, J.; Jurek, M.; Zymierska, D.; Wawro, A.; Petroutchik, A.; Juha, Libor; Hájková, Věra; Cihelka, Jaroslav; Chalupský, Jaromír; Burian, T.; Vyšín, Luděk; Toleikis, S.; Sokolowski-Tinten, K.; Stojanovic, N.; Zastrau, U.; London, R.; Hau-Riege, S.; Riekel, C.; Davies, R.; Burghammer, M.; Dynowska, E.; Szuszkiewicz, W.; Caliebe, W.; Nietubyc, R.

    2009-01-01

    Roč. 78, Suppl. 10 (2009), S46-S52 ISSN 0969-806X R&D Projects: GA AV ČR KAN300100702; GA MŠk LC510; GA MŠk(CZ) LC528; GA MŠk LA08024; GA AV ČR IAA400100701 Institutional research plan: CEZ:AV0Z10100523 Keywords : XUV FEL * radiation damage * ablation * structure modifications * x-ray diffraction Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.149, year: 2009

  6. Void shrinkage in stainless steel during high energy electron irradiation

    International Nuclear Information System (INIS)

    Singh, B.N.; Foreman, A.J.E.

    1976-03-01

    During irradiation of thin foils of an austenitic stainless steel in a high voltage electron microscope, steadily growing voids have been observed to suddenly shrink and disappear at the irradiation temperature of 650 0 Cthe phenomenon has been observed in specimens both with and withoutimplanted helium. Possible mechanisms for void shrinkage during irradiation are considered. It is suggested that the dislocation-pipe-diffusion of vacancies from or of self-interstitial atoms to the voids can explain the shrinkage behaviour of voids observed during our experiments. (author)

  7. High dose neutron irradiation damage in beryllium as blanket material

    Energy Technology Data Exchange (ETDEWEB)

    Chakin, V.P. E-mail: fae@niiar.ru; Kazakov, V.A.; Teykovtsev, A.A.; Pimenov, V.V.; Shimansky, G.A.; Ostrovsky, Z.E.; Suslov, D.N.; Latypov, R.N.; Belozerov, S.V.; Kupriyanov, I.B. E-mail: vniinm.400@g23.relkom.ru

    2001-11-01

    The paper presents the investigation results of beryllium products that operated in the SM and BOR-60 reactors up to neutron doses of 2.8x10{sup 22} and 8.0x10{sup 22} cm{sup -2} (E>1 MeV), respectively. The calculated and experimental data are given on helium and tritium accumulation, swelling, micro-hardness and thermal conductivity. The microstructural investigation results of irradiated beryllium are also presented. It is shown that the rate of helium and tritium accumulation in beryllium in the SM and BOR-60 reactors is high enough, which is of interest from the viewpoint of modeling the working conditions of the DEMO fusion reactor. Swelling of beryllium at irradiation temperature of 70-150 deg. C and neutron fluence of 2.8x10{sup 22} cm{sup -2} (E>1 MeV) makes up 0.8-1.5%, at 400 deg. C and fluence of 8x10{sup 22} cm{sup -2} (E>1 MeV)-3.2-5.0%. Irradiation hardening and decrease of thermal conductivity strongly depend on the irradiation temperature and are more significant at reduced temperatures. All results presented in the paper were analyzed with due account of the supposed working parameters of the DEMO fusion reactor blanket.

  8. High dose neutron irradiation damage in beryllium as blanket material

    International Nuclear Information System (INIS)

    Chakin, V.P.; Kazakov, V.A.; Teykovtsev, A.A.; Pimenov, V.V.; Shimansky, G.A.; Ostrovsky, Z.E.; Suslov, D.N.; Latypov, R.N.; Belozerov, S.V.; Kupriyanov, I.B.

    2001-01-01

    The paper presents the investigation results of beryllium products that operated in the SM and BOR-60 reactors up to neutron doses of 2.8x10 22 and 8.0x10 22 cm -2 (E>1 MeV), respectively. The calculated and experimental data are given on helium and tritium accumulation, swelling, micro-hardness and thermal conductivity. The microstructural investigation results of irradiated beryllium are also presented. It is shown that the rate of helium and tritium accumulation in beryllium in the SM and BOR-60 reactors is high enough, which is of interest from the viewpoint of modeling the working conditions of the DEMO fusion reactor. Swelling of beryllium at irradiation temperature of 70-150 deg. C and neutron fluence of 2.8x10 22 cm -2 (E>1 MeV) makes up 0.8-1.5%, at 400 deg. C and fluence of 8x10 22 cm -2 (E>1 MeV)-3.2-5.0%. Irradiation hardening and decrease of thermal conductivity strongly depend on the irradiation temperature and are more significant at reduced temperatures. All results presented in the paper were analyzed with due account of the supposed working parameters of the DEMO fusion reactor blanket

  9. Electronic control system for irradiation probes

    International Nuclear Information System (INIS)

    Gluza, E.; Neumann, J.; Zahalka, F.

    1980-01-01

    The EROS-78 system for the supply and power control of six heating sections of the irradiation probe of the CHOUCA type placed in the reactor vessel is described. The system allows temperature control at the location of the heat sensor with an accuracy of +-1% of the rated value within the region of 100 to 1000 degC. The equipment is provided with its own quartz controlled clock. The temperature is picked up by a chromel-alumel jacket thermocouple. The power input of the heating elements is thyristor controlled. (J.B.)

  10. Radiosensitivity of chlorella after medium energy accelerated electron irradiation

    International Nuclear Information System (INIS)

    Roux, J.C.

    1966-06-01

    The survival curves (capability of multiplication) of chlorella pyrenoidosa after irradiations can be used for soft electrons (0.65 and 1 MeV), hence penetrating into only 2 to 4 millimeters of water: the algae are laying on porous membranes and the doses are calculated from the power of the electron beam measured by the electric current on a metallic target or by Fricke's dosimetry. With these techniques, it is showed and discussed the part of anoxia in the radioprotection (magnitude or reduction of the dose calculated from the slope of survival curves: 2.5 ) that is more important than the restoration studied by the fractionation of the dose. The 0.65 and 1 MeV electrons have a biologic effect lesser than 180 keV X-rays (RBE - relative biological efficiency - calculated on the slope of survival curves is 0.92 in aerated irradiation, 0.56 in the deoxygenated irradiation). (author) [fr

  11. Degradation behaviour of fiber reinforced plastic under electron beam irradiation

    International Nuclear Information System (INIS)

    Sonoda, Katsumi; Yamamoto, Yasushi; Hashimoto, Osamu

    1989-01-01

    Various mechanical properties of four kinds of glass fiber-reinforced plastics irradiated with electron beams were examined at three temperatures; room temperature, 123 K and 77 K. Dynamic viscoelastic properties were measured, and fractography by means of scanning electron microscopy was observed in order to clarify degradation behaviour. A considerable decrease in interlaminar shear strength (ILSS) at room temperature was observed above 60 MGy. On the other hand, the three-point bending strength at 77 K and the ILSS at 123 K decreased with increasing irradiation. Fractography reveals that the degradation of the interface layer between matrix resin and fiber plays an important role in the strength reduction at 123 K and 77 K. These findings suggest that the interface between matrix resin and fiber loses its bondability at 123 K arid 77 K after electron beam irradiation. (author)

  12. The use of electron accelerators for fresh fruit irradiation

    International Nuclear Information System (INIS)

    Ferdes, O.; Minea, R.

    2000-01-01

    There are presented the results of tests concerning the effects of accelerated electron-beam to some early fresh fruits like strawberries, cherries, sour-cherries and apples. The irradiation were performed on common varieties, in normal conditions, to the NILPRP-Electron Accelerator Laboratory facility consisting in electron-beam accelerators which have the following parameters: - mean beam current, 5 μA; - electron mean energy approximately, 7 MeV; - pulse period, 3.5 μs. The doses varied between 0.5-3.0 kGy and the dose rate was about 1500 Gy/min. It was determined the fruit shelf life and there were analysed the main organoleptic and nutritional properties, as: size, shape, colour, dry weight, acidity, total and reducing sugars, ascorbic acid content and other. For the electron-beam treated fruits it was pointed out an increase in freshness and shelf life extension by 5-7 days for strawberries and more than two weeks for cherries. Otherwise, for the applied doses, the electron-beam irradiation did not produce any significant changes in the fruit characteristic values. These results lead to the conclusion that the electron accelerators could be successfully used as a technological solution for the fresh fruits processing, in view of shelf life extension. There are presented also some technical and economical considerations on the feasibility of this technology and on the use of electron-beam machines for food irradiation. (authors)

  13. [Scanning electron microscopy of heat-damaged bone tissue].

    Science.gov (United States)

    Harsanyl, L

    1977-02-01

    Parts of diaphyses of bones were exposed to high temperature of 200-1300 degrees C. Damage to the bone tissue caused by the heat was investigated. The scanning electron microscopic picture seems to be characteristic of the temperature applied. When the bones heated to the high temperature of 700 degrees C characteristic changes appear on the periostal surface, higher temperatura on the other hand causes damage to the compact bone tissue and can be observed on the fracture-surface. Author stresses the importance of this technique in the legal medicine and anthropology.

  14. Recovery of electron irradiated V-Ga alloys

    International Nuclear Information System (INIS)

    Leguey, T.; Monge, M.; Pareja, R.; Hodgson, E.R.

    2000-01-01

    The recovery characteristics of electron-irradiated V-Ga alloys with 1.2 and 4.6 at.% Ga have been investigated by positron annihilation spectroscopy (PAS). It is found that vacancies created by electron irradiation become mobile in these alloys at ∼293 K. This temperature is noticeably lower than that in pure V and V-Ti alloys. The vacancies aggregate into microvoids in V-4.6Ga, but do not in V-1.2Ga. The results indicate that vacancies are bound to Ga-interstitial impurity pairs

  15. Variation of carrier concentration and interface trap density in 8MeV electron irradiated c-Si solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, Sathyanarayana, E-mail: asharao76@gmail.com; Rao, Asha, E-mail: asharao76@gmail.com [Department of Physics, Mangalore Institute of Technology and Engineering, Moodabidri, Mangalore-574225 (India); Krishnan, Sheeja [Department of Physics, Sri Devi Institute of Technology, Kenjar, Mangalore-574142 (India); Sanjeev, Ganesh [Microtron Centre, Department of Physics, Mangalore University, Mangalagangothri-574199 (India); Suresh, E. P. [Solar Panel Division, ISRO Satellite Centre, Bangalore-560017 (India)

    2014-04-24

    The capacitance and conductance measurements were carried out for c-Si solar cells, irradiated with 8 MeV electrons with doses ranging from 5kGy – 100kGy in order to investigate the anomalous degradation of the cells in the radiation harsh environments. Capacitance – Voltage measurements indicate that there is a slight reduction in the carrier concentration upon electron irradiation due to the creation of radiation induced defects. The conductance measurement results reveal that the interface state densities and the trap time constant increases with electron dose due to displacement damages in c-Si solar cells.

  16. The co-evolution of microstructure features in self-ion irradiated HT9 at very high damage levels

    Energy Technology Data Exchange (ETDEWEB)

    Getto, E., E-mail: getto@usna.edu [Department of Mechanical Engineering, United States Naval Academy, Annapolis, MD, 21402 (United States); Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, 48109 (United States); Vancoevering, G.; Was, G.S. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, 48109 (United States)

    2017-02-15

    Understanding the void swelling and phase evolution of reactor structural materials at very high damage levels is essential to maintaining safety and longevity of components in Gen IV fast reactors. A combination of ion irradiation and modeling was utilized to understand the microstructure evolution of ferritic-martensitic alloy HT9 at high dpa. Self-ion irradiation experiments were performed on alloy HT9 to determine the co-evolution of voids, dislocations and precipitates up to 650 dpa at 460 °C. Modeling of microstructure evolution was conducted using the modified Radiation Induced Microstructure Evolution (RIME) model, which utilizes a mean field rate theory approach with grouped cluster dynamics. Irradiations were performed with 5 MeV raster-scanned Fe{sup 2+} ions on samples pre-implanted with 10 atom parts per million He. The swelling, dislocation and precipitate evolution at very high dpa was determined using Analytical Electron Microscopy in Scanning Transmission Electron Microscopy (STEM) mode. Experimental results were then interpreted using the RIME model. A microstructure consisting only of dislocations and voids is insufficient to account for the swelling evolution observed experimentally at high damage levels in a complicated microstructure such as irradiated alloy HT9. G phase was found to have a minimal effect on either void or dislocation evolution. M{sub 2}X played two roles; a variable biased sink for defects, and as a vehicle for removal of carbon from solution, thus promoting void growth. When accounting for all microstructure interactions, swelling at high damage levels is a dynamic process that continues to respond to other changes in the microstructure as long as they occur.

  17. In which metals are high electronic excitations able to create damage?

    International Nuclear Information System (INIS)

    Legrand, P.; Dunlop, A.; Lesueur, D.; Lorenzelli, N.; Morillo, J.; Bouffard, S.

    1992-01-01

    Since a few years a certain number of results have shown that high energy deposition through electronic excitation can lead to damage creation in metallic targets. In order to test which is the right parameter favouring damage creation (high d-electrons density favouring electron-phonon coupling, various electrical conductivities, existence of different displacive phase transformations . . .) chosen metallic targets (Zr, Co, Ti, Ag, Pd, Pt, W, Ni) were irradiated on the french accelerator GANIL in Caen, at cryogenic temperatures with GeV-ions (Pb, O). In situ electrical resistance variation measurements at low temperature were achieved, followed by isochronal annealing of defects and post-X-ray observations at room temperature. This study shows that a very strong enhancement of the damage production occurs only in Zr, Ti and Co which present different allotropic phases and in particular a displacive transformation associated with soft modes in the phonon spectrum. The structure of stage I recovery of all the samples depends on the electronic stopping power

  18. Study of damaged depth profiles of ion-irradiated PEEK

    Czech Academy of Sciences Publication Activity Database

    Vacík, Jiří; Hnatowicz, Vladimír; Červená, Jarmila; Apel, P. Yu.; Posta, S.; Kobayashi, Y.

    2007-01-01

    Roč. 201, 19-20 (2007), s. 8370-8372 ISSN 0257-8972 R&D Projects: GA MPO(CZ) 1H-PK2/05; GA MŠk 1P04LA213 Institutional research plan: CEZ:AV0Z10480505 Keywords : Oxygen irradiation * Poly-aryl-ether-ether ketone * Thermal neutron depth profiling (TNDP) Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.678, year: 2007

  19. Damage of the forest tree layer exposed to the acute gamma- irradiation in different phenophases

    International Nuclear Information System (INIS)

    Karaban', R.T.; Mishenkov, N.N.; Spirin, D.A.; Prister, B.S.; Aleksakhin, R.M.

    1980-01-01

    A programme of radioecological investigations using a specially designed powerful accurate source of gamma radiation (32 kCi 137 Cs) has been initiated in our country to study the consequences of the acute forest irradiation. The irradiation has been carried out twice - in autumn (September, 1973) and in spring (May, 1977). Pine and birch sections of the forest 26-30 years old have been subjected to irradiation. Exposures during autumn and spring irradiation constitute 16 and 8 days, respectively. Forest irradiation has been carried out so as to form isodose sections of considerable square to have a sufficient amount of tress in every isodose section. Pine-trees that perished due to the effect of ionizing radiation have been counted. Presented are the data on pine trees that perished depending on the dose absorbed and new pine shoots one year old (shoots of 1978) depending on the dose in the second year after spring irradiation. The data on the damage of shoots and buds used as the indices of pine radiation damage have been used to forecast that LD 100 for the period of acute effects (4-5 years) in the case of spring irradiation is approximately 1.5-2 krad, i.e. the spring effect on pine trees is 2-2.7 times more radiosensitive, than in autumn. The supposition is made that doses absorbed (about 1-2 krad) are minimum lethal doses for coniferous forests when irradiating them in most radiosensitive phases

  20. Evolution of graphene nanoribbons under low-voltage electron irradiation

    KAUST Repository

    Zhu, Wenpeng

    2012-01-01

    Though the all-semiconducting nature of ultrathin graphene nanoribbons (GNRs) has been demonstrated in field-effect transistors operated at room temperature with ∼105 on-off current ratios, the borderline for the potential of GNRs is still untouched. There remains a great challenge in fabricating even thinner GNRs with precise width, known edge configurations and specified crystallographic orientations. Unparalleled to other methods, low-voltage electron irradiation leads to a continuous reduction in width to a sub-nanometer range until the occurrence of structural instability. The underlying mechanisms have been investigated by the molecular dynamics method herein, combined with in situ aberration-corrected transmission electron microscopy and density functional theory calculations. The structural evolution reveals that the zigzag edges are dynamically more stable than the chiral ones. Preferential bond breaking induces atomic rings and dangling bonds as the initial defects. The defects grow, combine and reconstruct to complex edge structures. Dynamic recovery is enhanced by thermal activation, especially in cooperation with electron irradiation. Roughness develops under irradiation and reaches a plateau less than 1 nm for all edge configurations after longtime exposure. These features render low-voltage electron irradiation an attractive technique in the fabrication of ultrathin GNRs for exploring the ultimate electronic properties. © 2012 The Royal Society of Chemistry.

  1. Absorption and luminescence of crystalline quartz under electron nanosecond irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Gritsenko, B P; Lisitsyn, V M; Stepanchuk, V N [Tomskij Politekhnicheskij Inst. (USSR)

    1981-02-01

    The purpose of the study is continuation of investigations of principal regularities of production and destruction of short-lived defects in quartz and accompanying luminescence under electron pulse irradiation. For investigation purposes samples of crystalline synthetic quartz have been used. The irradiation has been performed at 80-400 K temperatures by means of an electron pulse accelerator with parameters: electron flow pulse duration 10 ns, pulse current density up to 1000 A/cm/sup 2/, electron mean energy 200 keV. Temperature-time characteristics of absorption and luminescence spectrum are studied. It has been found that quartz irradiation by electron pulses of nanosecond duration leads to appearance of short-lived bands of optical absorption at 4.1 and 5.15 eV to which by kinetic parameters correspond luminescence bands at 2.6 and 3.1 eV, respectively. The enumerated absorption bands are induced by quartz irradiation independently of the prehistory and phase state of the sample and are caused obviously by intrinsic radiation defects. Possible models of such defects are suggested.

  2. Cluster dynamics models of irradiation damage accumulation in ferritic iron. I. Trap mediated interstitial cluster diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Kohnert, Aaron A.; Wirth, Brian D. [University of Tennessee, Knoxville, Tennessee 37996-2300 (United States)

    2015-04-21

    The microstructure that develops under low temperature irradiation in ferritic alloys is dominated by a high density of small (2–5 nm) defects. These defects have been widely observed to move via occasional discrete hops during in situ thin film irradiation experiments. Cluster dynamics models are used to describe the formation of these defects as an aggregation process of smaller clusters created as primary damage. Multiple assumptions regarding the mobility of these damage features are tested in the models, both with and without explicit consideration of such irradiation induced hops. Comparison with experimental data regarding the density of these defects demonstrates the importance of including such motions in a valid model. In particular, discrete hops inform the limited dependence of defect density on irradiation temperature observed in experiments, which the model was otherwise incapable of producing.

  3. Evaluation of electron beam irradiation for disinfection of turmeric fingers

    Energy Technology Data Exchange (ETDEWEB)

    Yasumoto, Kyoden; Fujino, Masayuki; Supriyadi (Kyoto Univ., Uji (Japan). Research Inst. for Food Science); Suzuki, Tetsuya; Hayashi, Toru

    1991-08-01

    Turmeric finger as one of the most popular spices has been widely used for food manufacturing. However, it has also been a major cause of bacterial infestation of food materials especially in curry, ham and sausage manufacturing. In this study decontamination of bacteria in turmeric finger by electron beam irradiation was evaluated by comparing with several other decontamination methods: i.e., boiling, microwave irradiation, treatment by twin screw extruder and gamma-ray irradiation. By estimation of colony counting on nutrient agar plate, turmeric finger without any treatment gave total viable cell at 10{sup 8}/g. Turmeric finger which was irradiated by electron beam at 10 kGy dose dramatically reduced thermotolerant cell population below self restriction level (<1000/g), which has been required by food hygiene law. The same level of sterilization effect was obtained only by gamma-ray irradiation at 10 kGy and 20 kGy. On the other hand, although treatment through twin screw extruder slightly reduced bacterial numbers, neither boiling nor microwave irradiation gave sufficient decontamination effect on turmeric fingers. (author).

  4. Evaluation of electron beam irradiation for disinfection of turmeric fingers

    International Nuclear Information System (INIS)

    Yasumoto, Kyoden; Fujino, Masayuki; Supriyadi; Suzuki, Tetsuya; Hayashi, Toru.

    1991-01-01

    Turmeric finger as one of the most popular spices has been widely used for food manufacturing. However, it has also been a major cause of bacterial infestation of food materials especially in curry, ham and sausage manufacturing. In this study decontamination of bacteria in turmeric finger by electron beam irradiation was evaluated by comparing with several other decontamination methods: i.e., boiling, microwave irradiation, treatment by twin screw extruder and gamma-ray irradiation. By estimation of colony counting on nutrient agar plate, turmeric finger without any treatment gave total viable cell at 10 8 /g. Turmeric finger which was irradiated by electron beam at 10 kGy dose dramatically reduced thermotolerant cell population below self restriction level (<1000/g), which has been required by food hygiene law. The same level of sterilization effect was obtained only by gamma-ray irradiation at 10 kGy and 20 kGy. On the other hand, although treatment through twin screw extruder slightly reduced bacterial numbers, neither boiling nor microwave irradiation gave sufficient decontamination effect on turmeric fingers. (author)

  5. Evaluation of electron beam irradiation for disinfection of turmeric fingers

    International Nuclear Information System (INIS)

    Yasumoto, K.; Fujino, M.; Supriyadi; Suzuki, T.; Hayashi, T.

    1991-01-01

    Turmeric finger as one of the most popular spices has been widely used for food manufacturing. However, it has also been a major cause of bacterial infestation of food materials especially in curry, ham and sausage manufacturing. In this study decontamination of bacteria in turmeric finger by electron beam irradiation was evaluated by comparing with several other decontamination methods: i.e., boiling, microwave irradiation, treatment by twin screw extruder and gamma-ray irradiation. By estimation of colony counting on nutrient agar plate, turmeric finger without any treatment gave total viable cell at 10 8 /g. Turmeric finger which was irradiated by electron beam at 10kGy dose dramatically reduced thermotolerant cell population below self restriction level (<1000/g), which has been required by food hygiene law. The same level of sterilization effect was obtained only by gamma-ray irradiation at 10kGy and 20kGy. On the other hand, although treatment through twin screw extruder slightly reduced bacterial numbers, neither boiling nor microwave irradiation gave sufficient decontamination effect on turmeric fingers

  6. Damage accumulation in MgO irradiated with MeV Au ions at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Bachiller-Perea, Diana, E-mail: dianabachillerperea@gmail.com [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Univ. Paris-Sud, CNRS-IN2P3, Université Paris-Saclay, 91405, Orsay Cedex (France); Centro de Micro-Análisis de Materiales, Universidad Autónoma de Madrid, C/Faraday 3, 28049, Madrid (Spain); Dpto. de Física Aplicada, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, 28049, Madrid (Spain); Debelle, Aurélien, E-mail: aurelien.debelle@u-psud.fr [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Univ. Paris-Sud, CNRS-IN2P3, Université Paris-Saclay, 91405, Orsay Cedex (France); Thomé, Lionel [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Univ. Paris-Sud, CNRS-IN2P3, Université Paris-Saclay, 91405, Orsay Cedex (France); Behar, Moni [Instituto de Física, Universidade Federal do Rio Grande do Sul, C.P. 15051, 91501-970, Porto Alegre, RS (Brazil)

    2016-09-15

    The damage accumulation process in MgO single crystals under medium-energy heavy ion irradiation (1.2 MeV Au) at fluences up to 4 × 10{sup 14} cm{sup −2} has been studied at three different temperatures: 573, 773, and 1073 K. Disorder depth profiles have been determined through the use of the Rutherford backscattering spectrometry in channeling configuration (RBS/C). The analysis of the RBS/C data reveals two steps in the MgO damage process, irrespective of the temperature. However, we find that for increasing irradiation temperature, the damage level decreases and the fluence at which the second step takes place increases. A shift of the damage peak at increasing fluence is observed for the three temperatures, although the position of the peak depends on the temperature. These results can be explained by an enhanced defect mobility which facilitates defect migration and may favor defect annealing. X-ray diffraction reciprocal space maps confirm the results obtained with the RBS/C technique. - Highlights: • High-temperature MeV-ion irradiated MgO exhibits a two-step damage process. • The occurrence of the second step is delayed with increasing temperature. • The damage level decreases with increasing temperature. • A shift of the damage peak is observed with increasing fluence. • A high defect mobility at high temperatures in MgO is clearly evidenced.

  7. DNA Damage Induction and Repair Evaluated in Human Lymphocytes Irradiated with X-Rays an Neutrons

    International Nuclear Information System (INIS)

    Niedzwiedz, W.; Cebulska-Wasilewska, A.

    2000-12-01

    The objective of this study was to evaluate the kinetic of the DNA damage induction and their subsequent repair in human lymphocytes exposed to various types of radiation. PBLs cells were isolated from the whole blood of two young healthy male subjects and one skin cancer patient, and than exposed to various doses of low LET X-rays and high LET neutrons from 252 Cf source. To evaluate the DNA damage we have applied the single cell get electrophoresis technique (SCGE) also known as the comet assay. In order to estimate the repair efficiency, cells, which had been irradiated with a certain dose, were incubated at 37 o C for various periods of time (0 to 60 min). The kinetic of DNA damage recovery was investigated by an estimation of residual DNA damage persisted at cells after various times of post-irradiation incubation (5, 10, 15, 30 and 60 min). We observed an increase of the DNA damage (reported as a Tail DNA and Tail moment parameters) in linear and linear-quadratic manner, with increasing doses of X-rays and 252 Cf neutrons, respectively. Moreover, for skin cancer patient (Code 3) at whole studied dose ranges the higher level of the DNA damage was observed comparing to health subjects (Code 1 and 2), however statistically insignificant (for Tail DNA p=0.056; for Tail moment p=0.065). In case of the efficiency of the DNA damage repair it was observed that after 1 h of post-irradiation incubation the DNA damage induced with both, neutrons and X-rays had been significantly reduced (from 65% to 100 %). Furthermore, in case of skin cancer patient we observed lover repair efficiency of X-rays induced DNA damage. After irradiation with neutrons within first 30 min, the Tail DNA and Tail moment decreased of about 50%. One hour after irradiation, almost 70% of residual and new formed DNA damage was still observed. In this case, the level of unrepaired DNA damage may represent the fraction of the double strand breaks as well as more complex DNA damage (i.e.-DNA or DNA

  8. Characterisation of radiation damage in perovskite using high angular resolution electron channeling x-ray spectroscopy (HARECXS)

    International Nuclear Information System (INIS)

    Smith, K.L.; Zaluzec, N.J.

    2002-01-01

    Full text: Predicting and/or modelling the occurrence of radiation damage induced defects and their effects on physical properties (eg. amorphisation induced swelling, electrical conductivity., optical response etc.) in ceramic phases requires knowledge of the displacement energies, E d , of cations and anions in those phases. In this study, High Angular Resolution Electron Channelling X-ray Spectroscopy (HARECXS) spectra were collected from perovskite (CaTiO 3 ) samples that had been exposed to high-energy electrons or high-energy heavy ions. Calculations based on experimental data were then used to indicate the E d of the cations in perovskite. The HARECXS measurements were conducted on a Philips EM 420T AEM (LaB6 source, operated at 120 kV) fitted with an EDAX ultra thin window Si(Li) detector. The specimen was first manually oriented to an appropriate zone axis. Then control of the relative orientation of the incident probe was accomplished via direct computer control of the beam tilt coils, Typical acquisition times for a complete two-dimensional scan were 18-24 hours, while one dimensional scans ranged from 1-5 hours. Our experiments established that: a) HARECXS can detect radiation damage in perovskite caused by either high energy heavy ions or high energy electrons, b) the HARECXS signature of perovskite shows a systematic change with ion dose, c) HARECXS detects damage in perovskite that has been irradiated with 900kV electrons and does not detect damage in perovskite that has been irradiated with 620kV electrons, indicating the existance of an electron irradiation damage threshold. Calculations based on the latter results indicate that the displacement energy, E d of calcium and titanium in perovskite lie between 50 and 85eV. Copyright (2002) Australian Society for Electron Microscopy Inc

  9. 1-Chloronaphthalene decomposition in air using electron beam irradiation

    International Nuclear Information System (INIS)

    Chmielewski, A.G.; Sun, Y.; Bulka, S.; Zimek, Z.

    2006-01-01

    A method for the preparation of model gas containing 1-chloronaphthalene can be referred to 1,1-DCE (dichloroethene). A pulsed electron beam (EB) accelerator ILU-6 (2.0 MeV max., 20 kW max.) was used as an irradiation source. The absorbed dose rate inside the irradiation vessel was 10.835 kGy/min. Total absorbed dose was adjusted by changing irradiation time of the Pyrex glass vessels. 1-Chloronaphthalene concentration was analyzed using gas-chromatography. It has been found, that 1-chloronaphthalene can be decomposed in air or N 2 using EB irradiation. Decomposition efficiency of 1-chloronaphthalene in air is higher than that in N 2 . Positive charge transfer reactions and OH radicals' reaction may play a main role in 1-chloronaphthalene decomposition process

  10. Application of electron irradiation to food containers and packaging materials

    International Nuclear Information System (INIS)

    Ueno, Koji

    2010-01-01

    Problems caused by microbial contamination and hazardous chemicals have attracted much attention in the food industry. The number of systems such as hygienic management systems and Hazard Analysis Critical Control Point (HACCP) systems adopted in the manufacturing process is increasing. As manufacturing process control has become stricter, stricter control is also required for microbial control for containers and packaging materials (from disinfection to sterilization). Since safe and reliable methods for sterilizing food containers and packaging materials that leave no residue are required, electron beam sterilization used for medical equipment has attracted attention from the food industry. This paper describes an electron irradiation facility, methods for applying electron beams to food containers and packaging materials, and products irradiated with electron beams. (author)

  11. Trapped electrons in irradiated single crystals of polyhydroxy compounds

    International Nuclear Information System (INIS)

    Box, H.C.; Budzinski, E.E.; Freund, H.G.; Potter, W.R.

    1979-01-01

    The intermolecular trapping of electrons has been observed in single crystals of dulcitol and L(+) arabinose x-irradiated at 4.2 0 K. Attribution of a major component of the ESR absorption to trapped electrons is based upon the character of the hyperfine pattern, which arises from multiple anisotropic hyperfine interactions with exchangeable protons, and on the g value of the absorption, which is always less than the free spin value. The removal of the trapped electron absorption upon irradiation with visible light has also been demonstrated. In these experiments all of the electrons are trapped in identical sites. This circumstance provides some important advantages in the study of the factors affecting the stabilization of charge in an environment of polarizable molecules

  12. Blood vessel damage correlated with irradiance for in vivo vascular targeted photodynamic therapy

    Science.gov (United States)

    Zhang, Jinde; Tan, Zou; Niu, Xiangyu; Lin, Linsheng; Lin, Huiyun; Li, Buhong

    2016-10-01

    Vascular targeted photodynamic therapy (V-PDT) has been widely utilized for the prevention or treatment of vascular-related diseases, including age-related macular degeneration, port-wine stains and prostate cancer. In order to quantitative assessment the blood vessel damage during V-PDT, nude mice were implanted with Titanium dorsal skin window chambers for in vivo V-PDT studies. For treatments, various irradiances including 50, 75, 100 and 200 mW/cm2 provided by a 532 nm semiconductor laser were performed with the same total light dose of 30 J/cm2 after the mice were intravenously injection of Rose Bengal for 25 mg/Kg body weight. Laser speckle imaging and microscope were used to monitor blood flow dynamics and vessel constriction during and after V-PDT, respectively. The V-PDT induced vessel damages between different groups were compared. The results show that significant difference in blood vessel damage was found between the lower irradiances (50, 75 and 100 mW/cm2) and higher irradiance (200 mW/cm2), and the blood vessel damage induced by V-PDT is positively correlated with irradiance. This study implies that the optimization of irradiance is required for enhancing V-PDT therapeutic efficiency.

  13. Exploring ultrashort high-energy electron-induced damage in human carcinoma cells

    International Nuclear Information System (INIS)

    Rigaud, O.; Fortunel, N.O.; Vaigot, P.; Cadio, E.; Martin, M.T.; Lundh, O.; Faure, J.; Rechatin, C.; Malka, V.; Gauduel, Y.A.

    2010-01-01

    In conventional cancer therapy or fundamental radiobiology research, the accumulated knowledge on the complex responses of healthy or diseased cells to ionizing radiation is generally obtained with low-dose rates. Under these radiation conditions, the time spent for energy deposition is very long compared with the dynamics of early molecular and cellular responses. The use of ultrashort pulsed radiation would offer new perspectives for exploring the 'black box' aspects of long irradiation profiles and favouring the selective control of early damage in living targets. Several attempts were previously performed using nanosecond or picosecond pulsed irradiations on various mammalian cells and radiosensitive mutants at high dose rate. The effects of single or multi-pulsed radiations on cell populations were generally analyzed in the framework of dose survival curves or characterized by 2D imaging of γ-H2AX foci and no increase in cytotoxicity was shown compared with a delivery at a conventional dose rate. Moreover, when multi-shot irradiations were performed, the overall time needed to obtain an integrated dose of several Grays again overlapped with the multi-scale dynamics of bio-molecular damage-repair sequences and cell signalling steps. Ideally, a single-shot irradiation delivering a well-defined energy profile, via a very short temporal window, would permit the approach of a real-time investigation of early radiation induced molecular damage within the confined spaces of cell compartments. Owing to the potential applications of intense ultrashort laser for radiation therapy, the model of the A431 carcinoma cell line was chosen. An ultrafast single-shot irradiation strategy was carried out with these radio-resistant human skin carcinoma cells, using the capacity of an innovating laser-plasma accelerator to generate quasi mono-energetic femtosecond electron bunches in the MeV domain and to deliver a very high dose rate of 10 13 Gy s -1 per pulse. The alkaline comet

  14. Prediction of irradiation damage effects by multi-scale modelling: EURATOM 3 Framework integrated project perfect

    International Nuclear Information System (INIS)

    Massoud, J.P.; Bugat, St.; Marini, B.; Lidbury, D.; Van Dyck, St.; Debarberis, L.

    2008-01-01

    Full text of publication follows. In nuclear PWRs, materials undergo degradation due to severe irradiation conditions that may limit their operational life. Utilities operating these reactors must quantify the aging and the potential degradations of reactor pressure vessels and also of internal structures to ensure safe and reliable plant operation. The EURATOM 6. Framework Integrated Project PERFECT (Prediction of Irradiation Damage Effects in Reactor Components) addresses irradiation damage in RPV materials and components by multi-scale modelling. This state-of-the-art approach offers potential advantages over the conventional empirical methods used in current practice of nuclear plant lifetime management. Launched in January 2004, this 48-month project is focusing on two main components of nuclear power plants which are subject to irradiation damage: the ferritic steel reactor pressure vessel and the austenitic steel internals. This project is also an opportunity to integrate the fragmented research and experience that currently exists within Europe in the field of numerical simulation of radiation damage and creates the links with international organisations involved in similar projects throughout the world. Continuous progress in the physical understanding of the phenomena involved in irradiation damage and continuous progress in computer sciences make possible the development of multi-scale numerical tools able to simulate the effects of irradiation on materials microstructure. The consequences of irradiation on mechanical and corrosion properties of materials are also tentatively modelled using such multi-scale modelling. But it requires to develop different mechanistic models at different levels of physics and engineering and to extend the state of knowledge in several scientific fields. And the links between these different kinds of models are particularly delicate to deal with and need specific works. Practically the main objective of PERFECT is to build

  15. Low energy electron-driven damage in biomolecules

    International Nuclear Information System (INIS)

    Sanche, L.

    2005-01-01

    The damage induced by the impact of low energy electrons (LEE) on biomolecules is reviewed from a radiobiological perspective with emphasis on transient anion formation. The major type of experiments, which measure the yields of fragments produced as a function of incident electron energy (0.1 - 30 eV), are briefly described. Theoretical advances are also summarized. Several examples are presented from the results of recent experiments performed in the gas-phase and on bio-molecular films bombarded with LEE under ultra-high vacuum conditions. These include the results obtained from DNA films and those obtained from the fragmentation of elementary components of the DNA molecule (i.e., the bases, sugar and phosphate group analogs and oligonucleotides) and of proteins (e.g. amino acids). By comparing the results from different experiments and theory, it is possible to determine fundamental mechanisms that are involved in the dissociation of the biomolecules and the production of single- and double-strand breaks in DNA. Below 15 eV, electron resonances (i.e., the formation of transient anions) play a dominant role in the fragmentation of all biomolecules investigated. These transient anions fragment molecules by decaying into dissociative electronically excited states or by dissociating into a stable anion and a neutral radical. These fragments can initiate further reactions within large biomolecules or with nearby molecules and thus cause more complex chemical damage. Dissociation of a transient anion within DNA may occur by direct electron attachment at the location of dissociation or by electron transfer from another subunit. Damage to DNA is dependent on the molecular environment, topology, type of counter ion, sequence context and chemical modifications. (author)

  16. Damage saturation effects on volume and resistivity changes induced by fission-fragment irradiation of copper

    International Nuclear Information System (INIS)

    Birtcher, R.C.; Blewitt, T.H.

    1981-01-01

    Damage production and saturation has been monitored in copper by simultaneous electrical resistivity- and length-change measurements. Damage was introduced by 235 U fission fragments at either 7 or 85 K. At both temperatures, the resistivity and length changes were linearly related to each other for resistivity changes less than 80% saturation resistivity. The linear relationship was the same for both irradiation temperatures and was the same as that observed previously for 10 B fission fragment irrations at 4 K. These results are interpreted to show that the resistivity change per defect is unaffected by irradiation under conditions which lead to interstitial clustering. (orig.)

  17. Depth distribution of displacement damage in α-iron under triple beam ion irradiation

    International Nuclear Information System (INIS)

    Horton, L.L.; Bentley, J.; Jesser, W.A.

    1981-01-01

    The depth dependence of the defect structures was determined for iron irradiated at 850 0 K with 4 MeV Fe 2+ and energetic helium and deuteron ions to 10 dpa and fusion levels of helium and deuterium. From the damage profiles, a sectioning depth of 0.9 μm was selected for studies of iron and bcc iron alloys, such as ferritic steels, utilizing similar irradiation parameters. A comparison of the experimental damage profile to the deposited energy and deposited ion profiles calculated by E-DEP-1 indicated a possible overestimate of the LSS stopping power of at least 22%

  18. Relationship between peel damage and the accumulation of limonene in four varieties of irradiated oranges

    International Nuclear Information System (INIS)

    Belli-Donini, M.L.; Baraldi, D.

    1977-01-01

    The effects of radiation with regard to damage in Citrus fruits are studied in relation to the concentration of limonene, the main component of the oil glands. Control samples of four orange varieties showed no exocarp damage during storage, whereas the irrdiated samples showed varying degrees of browning depending of variety, exposure (100 to 200 krads), storage temperature (5 and 20 0 C) and the ripening stage at which the oranges were irradiated. A correlation has been shown to exist between peel browning during storage and both extracted and volatile limonene content. Irradiation appeared to increase the permeability of the epidermal tissues and the synthesis of limonene. (author)

  19. Alleviation of acute radiation damages by post-irradiation treatments

    International Nuclear Information System (INIS)

    Kurishita, A.; Ono, T.

    1992-01-01

    Radiation induced hematopoietic and gastro-intestinal damages in mice were tried to alleviate experimentally by post-treatment. Combined treatment of OK-432 and aztreonam clearly prevented the radiation induced sepsis and elevated the survival rate in mice; the survival was 80% in the OK-432 plus aztreonam group while it was 55% in the group treated with OK-432 alone and 0% with saline. Irsogladine maleate, an anti-ulcer drug, increased the survival rate of jejunal crypt stem cells with a clear dose-related trend. The D 0 for irsogladine maleate was 2.8 Gy although it was 2.3 Gy for saline, These findings suggest that some conventional drugs are effective for radiation induced hematopoietic and gastro-intestinal damages and the possibility that they can be applied for people exposed to radiation accidentally. (author)

  20. Deuterium ion irradiation damage and deuterium trapping mechanism in candidate stainless steel material (JPCA2) for fusion reactor

    International Nuclear Information System (INIS)

    Ashizuka, Norihiro; Kurita, Takaaki; Yoshida, Naoaki; Fujiwara, Tadashi; Muroga, Takeo

    1987-01-01

    An improved austenitic stainless steel (JPCA), a candidate material for fusion reactor, is irradiated at room temperature with deuterium ion beams. Desorption spectra of deuterium gas is measured at various increased temperatures and defects formed under irradiation are observed by transmission electron microscopy to determine the mechanism of the thermal release of deuteriums and the characteristics of irradiation-induced defects involved in the process. In the deuterium deportion spectra observed, five release stages are found to exist at 90 deg C, 160 deg C, 220 deg C, 300 deg C and 400 deg C, referred to as Stage I, II, III, IV and V, respectively. Stage I is interpreted as representing the release of deuteriums trapped in point defects (presumably vacancies) formed under irradiation. The energy of desorption from the trapping sites is estimated at 0.8 eV. Stage II is concluded to be associated with the release of deuteriums trapped in a certain kind of existing defects. Stage III involves the release of deuteriums that are trapped in dislocations, dislocation loops or dislocated portions of stacking fault tetrahedra. This release occurs significantly in processed materials and other materials irradiated with high energy ion beams that may cause cascade damage. Stage IV is interpreted in terms of thermal decomposition of small deuterium clusters. Stage V is associated with the decomposition of rather large deuterium clusters grown on the {111} plane. (Nogami, K.)

  1. Ion irradiation and biomolecular radiation damage II. Indirect effect

    OpenAIRE

    Wang, Wei; Yu, Zengliang; Su, Wenhui

    2010-01-01

    It has been reported that damage of genome in a living cell by ionizing radiation is about one-third direct and two-thirds indirect. The former which has been introduced in our last paper, concerns direct energy deposition and ionizing reactions in the biomolecules; the latter results from radiation induced reactive species (mainly radicals) in the medium (mainly water) surrounding the biomolecules. In this review, a short description of ion implantation induced radical formation in water is ...

  2. Remarks on the mathematical description of materials damage by irradiation

    International Nuclear Information System (INIS)

    Steinbach, E.

    1987-01-01

    In describing radiation damage processes in materials, the chemical rate theory proves to be the most effective mathematical method. The applicability, and even the validity, of this theory, which has been successfully applied in many other scientific fields, have been questioned by some authors. After rigorous mathematical analysis of the relevant rate equations and the corresponding self-consistent calculation of sink strengths, the main criticisms on this subject can be disproved

  3. Challenges in validating radiation sterilization with low energy electron irradiation

    International Nuclear Information System (INIS)

    Miller, A.; Helt-Hansen, J.

    2011-01-01

    Complete text of publication follows. Low energy electron irradiation (80-300 keV) is used increasingly for sterilization or decontamination in connection with isolators for aseptic filling lines in the pharmaceutical industry. It is not defined how validation for this process shall be carried out. A method can be derived from the medical device standard for radiation sterilization, ISO 11137, because the principles described in this standard can be applied to almost any industrial irradiation process. The validations elements are: Process definition, concerning specification of the dose required for the process and the maximum acceptable dose for the product. Installation qualification, concerning acceptance the irradiation facility. Operational qualification, concerning characterization of the facility. Performance qualification, concerning setting up the process. Process control, concerning routine monitoring. The limited penetration of the low energy electrons leads to problems with respect to executing these validation steps. This paper discusses these problems, and shows with examples how they can be solved.

  4. Impact of electron irradiation on particle track etching response in ...

    Indian Academy of Sciences (India)

    In the present work, attempts have been made to investigate the modification in particle track etching response of polyallyl diglycol carbonate (PADC) due to impact of 2 MeV electrons. PADC samples pre-irradiated to 1, 10, 20, 40, 60, 80 and 100 Mrad doses of 2 MeV electrons were further exposed to 140 MeV 28Si beam ...

  5. Immunologic proof of DNS irradiation damages and their repair in stationary yeast cells

    International Nuclear Information System (INIS)

    Waller, H.

    1980-08-01

    In rabbits an antiserum was produced by injecting UV-irradiated denaturated calf-thymus DNS; after inhibiting unspecific bindings, a specific serological reaction with UV-induced irradiation damages could be taken as present in this antiserum. By the ammonium sulphate precipitation as immunologic method of detection, after UV-irradiation the genesis of damages at certain sites in the DNS of different yeast lineages and their repair was observed. The elemination of UV-induced DNS damages was observed after an incubation in a nutrien medium, after photo-reactivation and after combining both therapeutic treatments. The following results were obtained: the detected DNS damage (number of induced dimeres/yeast genomes) had the same degree in the four yeast lineages. Apart from the excision-negative mutante 2094 for all yeast lineages a repair efficiency of 60% could be detected. All yeast lineages presented themselves as photographically to be reactivated; however, in all cases a DNS damage of 40 to 50% remained. The examinations for the specificity of antiserum against roentgenologically irradiated DNS led to the conclusion that the antibody population of the serum consisted mainly of immunoglobulines against unchanged DNS areas. A specific immunological reaction of only about 10% could be achieved. (orig./MG) [de

  6. Effects of cavitation on damage calculations in ion-irradiated P7 alloy

    International Nuclear Information System (INIS)

    Sindelar, R.L.; Farrens, S.N.; Kulcinski, G.L.

    1985-01-01

    The purpose of this study is to investigate the effect of voids on the depth-dependent damage energy in ion-irradiated metals. Corrections to the dose at the swelling peak will be used to obtain the swelling rate of ion-irradiated 316-type stainless steels. Samples of the P7 alloy were ion-irradiated to four fluence levels up to a peak dose level of 100 dpa at 650 0 C. The depth-dependent void parameters extracted in cross section were used to model the effect of voids on the depth-dependent damage produced during 14 MeV nickel ion irradiation. An increase in the range of damage produced from the original foil surface for the target containing voids was modeled as a first-order correction to the damage profile. A second-order effect, void straggling, was shown to cause a time-dependent decrease in the damage rate at the peak swelling depth. Corrections applied to the dose at the peak swelling depth yield swelling rates approaching 0.7%/dpa

  7. The morphology of radiation damage in copper irradiated with neutrons at elevated temperatures

    International Nuclear Information System (INIS)

    Kemm, K.R.

    1977-01-01

    This thesis is an investigation of the radiation damage morphology of high purity copper crystals irradiated with fast neutrons at temperatures in the range of 250 to 400 degrees C. At these high temperatures neutron damage is found to accumulate into large 3-dimensional rafts up to 100 μm in size, and the well known homogeneous distribution of black dot damage which is characteristic of irradiations at low temperatures is not observed. The characteristics and composition of the rafts of damage at different temperatures in the range 250 to 400 degrees C have been compared and found to differ to a large extent. It has also been shown that the background areas between rafts contain a rather low density of damage at all temperatures studied. It is therefore concluded that many of the interstitial atoms formed during irradiation migrate over large distances through the crystal lattice to precipitate at the sites of the dislocations forming the large rafts, and so denuded inter-rafts areas are left behind. It is proposed that these large rafts originate from grown-in dislocations present in the crystal before irradiation

  8. A 20 keV electron gun system for the electron irradiation experiments

    International Nuclear Information System (INIS)

    Mahapatra, S.K.; Dhole, S.D.; Bhoraskar, V.N.

    2005-01-01

    An electron gun consisting of cathode, focusing electrode, control electrode and anode has been designed and fabricated for the electron irradiation experiments. This electron gun can provide electrons of any energy over the range 1-20 keV, with current upto 50 μA. This electron gun and a Faraday cup are mounted in the cylindrical chamber. The samples are fixed on the Faraday cup and irradiated with electrons at a pressure ∼10 -7 mbar. The special features of this electron gun system are that, at any electron energy above 1 keV, the electron beam diameter can be varied from 5 to 120 mm on the Faraday cup mounted at a distance of 200 mm from the anode in the chamber. The variation in the electron current over the beam spot of 120 mm diameter is less than 15% and the beam current stability is better than 5%. This system is being used for studying the irradiation effects of 1-20 keV energy electrons on the space quality materials in which the irradiation time may vary from a few tens of seconds to hours

  9. A 20 keV electron gun system for the electron irradiation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Mahapatra, S.K. [Department of Physics, University of Pune, Pune 411007 (India); Dhole, S.D. [Department of Physics, University of Pune, Pune 411007 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411007 (India)]. E-mail: vnb@physics.unipune.ernet.in

    2005-01-01

    An electron gun consisting of cathode, focusing electrode, control electrode and anode has been designed and fabricated for the electron irradiation experiments. This electron gun can provide electrons of any energy over the range 1-20 keV, with current upto 50 {mu}A. This electron gun and a Faraday cup are mounted in the cylindrical chamber. The samples are fixed on the Faraday cup and irradiated with electrons at a pressure {approx}10{sup -7} mbar. The special features of this electron gun system are that, at any electron energy above 1 keV, the electron beam diameter can be varied from 5 to 120 mm on the Faraday cup mounted at a distance of 200 mm from the anode in the chamber. The variation in the electron current over the beam spot of 120 mm diameter is less than 15% and the beam current stability is better than 5%. This system is being used for studying the irradiation effects of 1-20 keV energy electrons on the space quality materials in which the irradiation time may vary from a few tens of seconds to hours.

  10. Amorphization kinetics of Zr3Fe under electron irradiation

    International Nuclear Information System (INIS)

    Motta, A.T.; Howe, L.M.; Okamoto, P.R.

    1994-11-01

    Previous investigations using 40 Ar ion bombardments have revealed that Zr 3 Fe, which has an orthorhombic crystal structure, undergoes an irradiation-induced transformation from the crystalline to the amorphous state. In the present investigation, 0.9 MeV electron irradiations were performed at 28 - 220 K in a high-voltage electron microscope (HVEM). By measuring the onset, spread and final size of the amorphous region, factoring in the Gaussian distribution of the beam, a kinetic description of the amorphization in terms of dose, dose rate and temperature was obtained. The critical temperature for amorphization by electron irradiation was found to be ∼ 220 K, compared with 570 - 625 K for 40 Ar ion irradiation. Also, the dose-to-amorphization increased exponentially with temperature. Results indicated that the rate of growth of the amorphous region under the electron beam decreased with increasing temperature and the dose-to-amorphization decreased with increasing dose rate. The size of the amorphous region saturated after a given dose, the final size decreasing with increasing temperature, and it is argued that this is related to the existence of a critical dose rate, which increases with temperature, and below which no amorphization occurs. (author). 26 refs., 6 figs

  11. Electron spin resonance investigations on polycarbonate irradiated with U ions

    Energy Technology Data Exchange (ETDEWEB)

    Chipara, M.I.; Reyes-Romero, J

    2001-12-01

    Electron spin resonance investigations on polycarbonate irradiated with uranium ions are reported. The dependence of the resonance line parameters (line intensity, line width, double integral) on penetration depth and dose is studied. The nature of free radicals induced in polycarbonate by the incident ions is discussed in relation with the track structure. The presence of severe exchange interactions among free radicals is noticed.

  12. Effect of irradiation on kinetic behavior of Salmonella Typhimurium and Staphylococcus aureus in lettuce and damage of bacterial cell envelope

    International Nuclear Information System (INIS)

    Shim, Won-Bo; Je, Gil-Soo; Kim, Kyeongyeol; Mtenga, Adelard B.; Lee, Won-Gyeong; Song, Jeong-Un; Chung, Duck-Hwa; Yoon, Yohan

    2012-01-01

    This study evaluated effect of gamma irradiation on survival of Salmonella Typhimurium and Staphylococcus aureus on lettuce and damage of cell envelope. S. Typhimurium and S. aureus were inoculated on red leaf lettuce, and they were irradiated at 0, 0.5, 1, 1.5, 2, 2.5, and 3 kGy, and the samples were then stored at 7 and 25 °C for 7 days. Survival of S. Typhimurium and S. aureus were enumerated on xylose lysine deoxycholate agar and Baird–Parker agar, respectively. D 10 value (dose required to reduce 1 log CFU/leaf) was calculated, and kinetic parameters (maximum specific growth rate; μ max and lag phase duration; LPD) were calculated by the modified Gompertz model. In addition, cell envelope damage of the pathogens was observed by scanning electron microscope (SEM) and transmission electron microscope (TEM). D 10 values were 0.35 and 0.33 kGy for S. Typhimurium and S. aureus, respectively. During storage at 7 °C, S. Typhimurium and S. aureus had significant (P max , respectively. At 25 °C, cell counts of S. Typhimurium and S. aureus on the samples irradiated at 0 and 0.5 kGy increased (P max of both pathogens were higher in 0 kGy (1.08–2.27 log CFU/leaf/day) and 0.5 kGy (0.58–0.92 log CFU/leaf/day), and LPDs ranged from 1.53 to 3.14 day. SEM and TEM observations showed that cells irradiated at 1.5 and 3 kGy showed disrupted cell membrane. These results indicate that gamma irradiation could be a useful decontamination technology to improve food safety of lettuce by destroying cells of S. Typhimurium and S. aureus. - Highlights: ► Low dose of gamma irradiation destroyed cell envelope of the pathogens. ► Gamma irradiation decreased cell counts of the pathogens on lettuce. ► Gamma irradiation could be useful in improving food safety of lettuce.

  13. Behavior of high resistance to He{sup 2+} induced irradiation damage in metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bin [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Mei, Xianxiu, E-mail: xxmei@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Hou, Wenjing; Wang, Younian [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Wang, Zhiguang [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Dong, Chuang [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China)

    2013-10-01

    Highlights: •Metallic glasses and W were irradiated with 500 keV He{sup 2+} at different fluences. •Metallic glasses could maintain amorphous state at different irradiation fluences. •The resistance to He{sup 2+} irradiation of metallic glasses was superior to the one in W metal. •Cu- and Zr-based metallic glasses had better resistance to He{sup 2+} irradiation. -- Abstract: This study details the irradiation of various metallic glasses ((Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5}, Zr{sub 64}Cu{sub 17.8}Ni{sub 10.7}Al{sub 7.5}, Co{sub 61.2}B{sub 26.2}Si{sub 7.8}Ta{sub 4.8}) and metallic W using He{sup 2+} ions with an energy of 500 keV at irradiation fluences of 2 × 10{sup 17}, 1 × 10{sup 18} and 2 × 10{sup 18} ions/cm{sup 2} to investigate the radiation-resistant properties of these metallic glasses compared to the conventional irradiation-resistant material W. These three metallic glasses were able to maintain an amorphous state during these irradiation fluences. There was no significant irradiation damage at the low irradiation fluence. When the irradiation fluence was increased to 2 × 10{sup 18} ions/cm{sup 2}, a damage layer appeared up to a distance corresponding to the range of the ions away from the surfaces of the Cu- and Zr-based metallic glasses without any visible damage on the surface. Significant surface stripping damage appeared in the Co-based metallic glass. Relatively speaking, surface layer peeling appeared in metallic W along the crystal boundary at a fluence of 1 × 10{sup 18} ions/cm{sup 2}. When the fluence was increased to 2 × 10{sup 18} ions/cm{sup 2}, multilayer peeling, stripping, etc. appeared. The roughness of the Cu- and Zr-based metallic glass showed further smoothing with increasing fluence, while the opposite occurred in the Co-based metallic glass. Within the wavelength range of 400–1700 nm, after irradiation of He{sup 2+} at a fluence of 1 × 10{sup 18} ions/cm{sup 2}, the reflectance of the Cu-based and Co

  14. Change in the dibenzyldimethylammonium accumulation by irradiated Streptococcus cells caused by radiation damage modifiers

    International Nuclear Information System (INIS)

    Fomenko, B.S.; Leont'eva, G.A.

    1975-01-01

    Anoxia, concentrated cell suspension, glutathione (10 -4 -10 -2 M) or low concentrations of cysteine (10 -4 -10 -3 M) exerted a radioprotective effect and suppressed the accumulation of dibenzyldimethylammonium chloride (DDA + ) by γ-irradiated (40 krad) S. faecalis cells. Dilution of the cell suspensions and higher cysteine concentrations (>10 -3 M) increased the effects of irradiation on bacterial accumulation of DDA + and decreased the cell survival. The lethal action of irradiation apparently involves damage to the mechanisms which maintain a normal membrane potential

  15. Void nucleation at elevated temperatures under cascade-damage irradiation

    International Nuclear Information System (INIS)

    Semenov, A.A.; Woo, C.H.

    2002-01-01

    The effects on void nucleation of fluctuations respectively due to the randomness of point-defect migratory jumps, the random generation of free point defects in discrete packages, and the fluctuating rate of vacancy emission from voids are considered. It was found that effects of the cascade-induced fluctuations are significant only at sufficiently high total sink strength. At lower sink strengths and elevated temperatures, the fluctuation in the rate of vacancy emission is the dominant factor. Application of the present theory to the void nucleation in annealed pure copper neutron-irradiated at elevated temperatures with doses of 10 -4 -10 -2 NRT dpa showed reasonable agreement between theory and experiment. This application also predicts correctly the temporal development of large-scale spatial heterogeneous microstructure during the void nucleation stage. Comparison between calculated and experimental void nucleation rates in neutron-irradiated molybdenum at temperatures where vacancy emission from voids is negligible showed reasonable agreement as well. It was clearly demonstrated that the athermal shrinkage of relatively large voids experimentally observable in molybdenum at such temperatures may be easily explained in the framework of the present theory

  16. Electron beam irradiation facility for low to high dose irradiation applications

    International Nuclear Information System (INIS)

    Petwal, V.C.; Wanmode, Yashwant; Verma, Vijay Pal; Bhisikar, Abhay; Dwivedi, Jishnu; Shrivastava, P.; Gupta, P.D.

    2013-01-01

    Electron beam based irradiation facilities are becoming more and more popular over the conventional irradiator facilities due to many inherent advantages such as tunability of beam energy, availability of radiation both in electron mode and X-ray mode, wide range of the dose rate, control of radiation from a ON-OFF switch and other safety related merits. A prototype experimental facility based on electron accelerator has been set-up at RRCAT to meet the low-dose, medium dose and high-dose requirements for radiation processing of food, agricultural and medical products. The facility can be operated in the energy range from 7-10 MeV at variable power level from 0.05-3 kW to meet the dose rate requirement of 100 Gy to kGy. The facility is also equipped with a Bremsstrahlung converter optimized for X-ray irradiation at 7.5 MV. Availability of dose delivery in wide range with precision control and measurement has made the facility an excellent tool for researchers interested in electron/X-ray beam irradiation. A precision dosimetry lab based on alanine EPR and radiochromic film dosimetry system have been established to characterize the radiation field and precise dose measurements. Electron beam scattering technique has been developed to achieve low dose requirement for EB irradiation of various seeds such as groundnut, wheat, soybeans, moong beans, black gram etc. for mutation related studies. This paper describes various features of the facility together with the dosimetric measurements carried out for qualification of the facility and recent irradiation experiments carried out using this facility. (author)

  17. DNA damage by ethylbenzenehydroperoxide formed from carcinogenic ethylbenzene by sunlight irradiation

    International Nuclear Information System (INIS)

    Toda, Chitose; Uchida, Takafumi; Midorikawa, Kaoru; Murata, Mariko; Hiraku, Yusuke; Okamoto, Yoshinori; Ueda, Koji; Kojima, Nakao; Kawanishi, Shosuke

    2003-01-01

    Ethylbenzene, widely used in human life, is a non-mutagenic carcinogen. Sunlight-irradiated ethylbenzene caused DNA damage in the presence of Cu 2+ , but unirradiated ethylbenzene did not. A Cu + -specific chelator bathocuproine inhibited DNA damage and catalase showed a little inhibitory effect. The scopoletin assay revealed that peroxides and H 2 O 2 were formed in ethylbenzene exposed to sunlight. These results suggest that Cu + and alkoxyl radical mainly participate in DNA damage, and H 2 O 2 partially does. When catalase was added, DNA damage at thymine and cytosine was inhibited. Ethylbenzenehydroperoxide, identified by GC/MS analysis, induced the formation of 8-oxo-7,8-dihydro-2 ' -deoxyguanosine and caused DNA damage at consecutive guanines, as observed with cumenehydroperoxide. Equimolar concentrations of H 2 O 2 and acetophenone were produced by the sunlight-irradiation of 1-phenylethanol, a further degraded product of ethylbenzene. These results indicate a novel pathway that oxidative DNA damage induced by the peroxide and H 2 O 2 derived from sunlight-irradiated ethylbenzene may lead to expression of the carcinogenicity

  18. SPECTER-ANL, Neutron Damage for Material Irradiation

    International Nuclear Information System (INIS)

    1989-01-01

    1 - Description of program or function: SPECTER calculates spectral- averaged displacements, recoil spectra, gas production, and total damage energy (Kerma) for 41 pure elements using ENDF/B-V derived cross sections. The user need only specify a neutron energy spectrum. Because SPECTER does not handle compounds, SPECOMP was developed to determine displacement damage for alloys, insulators, and breeder materials. 2 - Method of solution: In SPECTER elastic scattering is treated exactly including angular distributions from ENDF/B-V. Inelastic scattering calculations consider both discrete and continuous nuclear level distributions. Multiple (n,xn) reactions use a Monte Carlo technique to derive the recoil distributions. The (n,d) and (n,t) reactions are treated as (n,p) and (n, 3 He) as (n, 4 He). The neutron-gamma reaction and subsequent beta-decay are also included, using a new treatment of gamma-gamma coincidences, angular correlations, beta-neutrino correlations and the incident neutron energy. The Lindhard model was used to compute the energy available for nuclear displacement at each recoil energy. SPECOMP reads the required files from SPECTER, computes secondary displacement functions for each combination of recoil and matrix atom, and then integrates over recoil energy to find the net displacement cross section at each neutron energy. Damage due to neutron, gamma-ray and beta decay events is then added in and the results are summed to obtain the total dpa cross section. 3 - Restrictions on the complexity of the problem: The DISCS computer code was used to process ENDF/B-V data for 41 pure elements for use with SPECTER-ANL. SPECOMP can use any combination of four elements in a single run

  19. Self-ion Irradiation Damage of F/M and ODS steels

    International Nuclear Information System (INIS)

    Kang, Suk Hoon; Chun, Young-Bum; Noh, Sanghoon; Jang, Jinsung; Kim, Tae Kyu

    2014-01-01

    Oxide dispersion strengthened (ODS) ferritic steels are potential high-temperature materials that are stabilized by dispersed particles at elevated temperatures. These dispersed particles improve the tensile strength and creep rupture strength, they are expected to increase the operation temperature up to approximately 650 .deg. C and also enhance the energy efficiency of the fusion reactor. Some reports described that the nano-clusters are strongly resistant to coarsening by annealing up to 1000 .deg. C, and nanoclusters do not change after ion irradiation up to 0.7 dpa at 300 .deg. C. ODS steels will be inevitably exposed to neutron irradiation condition; the irradiation damages, creep and swelling are always great concern. The dispersed oxide particles are believed to determine the performance of the steel, even the radiation resistance. In this study, F/M and ODS model alloys of Korea Atomic Energy Research Institute (KAERI) were irradiated by Fe 3+ self-ion to emulate the neutron irradiation effect. In this study, Fe 3+ self-ion irradiation is used as means of introducing radiation damage in F/M steel and ODS steel. The ion accelerator named DuET (in Kyoto University, Japan) was used for irradiation of Fe 3+ ion by 6.4 MeV at 300 .deg. C. The maximum damage rate in F/M and ODS steels were estimated roughly 6 dpa. After radiation, point or line defects were dominantly observed in F/M steel, on the other hands, small circular cavities were typically observed in ODS steel. Nanoindentation is a useful tool to determine the irradiationinduced hardness change in the damage layer of ionirradiated iron base alloys

  20. Surgical management of irradiation-induced small bowel damage

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.T.; Seski, J.C.; Copeland, L.J.; Gershenson, D.M.; Edwards, C.L.; Herson, J.

    1985-04-01

    Seventy-seven patients, presenting with radiation small bowel injuries at the University of Texas M. D. Anderson Hospital and Tumor Institute at Houston between 1962 and 1978, were analyzed retrospectively. The patients were divided into two categories: bowel bypass without resection, and resection of irradiated bowel. Each group was then analyzed for its short- and long-term complications. Ileocolectomy with end-to-end anastomosis was the surgical procedure of choice in those people undergoing resection. There was no difference in short-term complications noted between the two groups. The long-term complications of fistula formation and continued small bowel necrosis could be prevented by resection, as a primary procedure. The surgical details of ileocolectomy with end-to-end anastomosis are presented, along with an analysis of the complications encountered in both groups.

  1. Surgical management of irradiation-induced small bowel damage

    International Nuclear Information System (INIS)

    Smith, S.T.; Seski, J.C.; Copeland, L.J.; Gershenson, D.M.; Edwards, C.L.; Herson, J.

    1985-01-01

    Seventy-seven patients, presenting with radiation small bowel injuries at the University of Texas M. D. Anderson Hospital and Tumor Institute at Houston between 1962 and 1978, were analyzed retrospectively. The patients were divided into two categories: bowel bypass without resection, and resection of irradiated bowel. Each group was then analyzed for its short- and long-term complications. Ileocolectomy with end-to-end anastomosis was the surgical procedure of choice in those people undergoing resection. There was no difference in short-term complications noted between the two groups. The long-term complications of fistula formation and continued small bowel necrosis could be prevented by resection, as a primary procedure. The surgical details of ileocolectomy with end-to-end anastomosis are presented, along with an analysis of the complications encountered in both groups

  2. Effect of ATM heterozygosity on heritable DNA damage in mice following paternal F0 germline irradiation

    International Nuclear Information System (INIS)

    Baulch, Janet E.; Li, M.-W.; Raabe, Otto G.

    2007-01-01

    The ataxia telangiectasia mutated (ATM) gene product maintains genome integrity and initiates cellular DNA repair pathways following exposures to genotoxic agents. ATM also plays a significant role in meiotic recombination during spermatogenesis. Fertilization with sperm carrying damaged DNA could lead to adverse effects in offspring including developmental defects or increased cancer susceptibility. Currently, there is little information regarding the effect of ATM heterozygosity on germline DNA repair and heritable effects of paternal germline-ionizing irradiation. We used neutral pH comet assays to evaluate spermatozoa 45 days after acute whole-body irradiation of male mice (0.1 Gy, attenuated 137 Cs γ rays) to determine the effect of ATM heterozygosity on delayed DNA damage effects of Type A/B spermatogonial irradiation. Using the neutral pH sperm comet assay, significant irradiation-related differences were found in comet tail length, percent tail DNA and tail extent moment, but there were no observed differences in effect between wild-type and ATM +/- mice. However, evaluation of spermatozoa from third generation descendants of irradiated male mice for heritable chromatin effects revealed significant differences in DNA electrophoretic mobility in the F 3 descendants that were based upon the irradiated F 0 sire's genotype. In this study, radiation-induced chromatin alterations to Type A/B spermatogonia, detected in mature sperm 45 days post-irradiation, led to chromatin effects in mature sperm three generations later. The early cellular response to and repair of DNA damage is critical and appears to be affected by ATM zygosity. Our results indicate that there is potential for heritable genetic or epigenetic changes following Type A/B spermatogonial irradiation and that ATM heterozygosity increases this effect

  3. Electron beam deposition system causing little damage to organic layers

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Minoru [Research Center for Solar Energy Chemistry, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Business Incubation Department, Hitachi Zosen Corporation, 2-11 Funamachi 2-Chome, Taisho-ku, Osaka 551-0022 (Japan); Matsumura, Michio, E-mail: matsu@chem.es.osaka-u.ac.jp [Research Center for Solar Energy Chemistry, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Maeda, Yasuhiro [Business Incubation Department, Hitachi Zosen Corporation, 2-11 Funamachi 2-Chome, Taisho-ku, Osaka 551-0022 (Japan)

    2011-07-29

    Conditions for deposition of an aluminum (Al) layer on an organic light-emitting layer with an electron beam (EB) deposition system were optimized with respect to deposition rate and damage to organic layers. The damage to the organic layers was found to be mostly caused by X-rays emitted from a target bombarded with accelerated electrons. In order to decrease the X-ray intensity while maintaining a high deposition rate, we used an EB source which emits high-density EB at low acceleration voltage. In addition, we inserted a heat reflector and a sintered-carbon liner between the Al target and copper crucible to improve heat insulation. As a result, the voltage needed for the deposition of Al electrodes at a rate of about 8 nm/s was lowered from normal voltages of 2.0 kV or higher to as low as 1.5 kV. To reduce the number of electrons hitting the substrate, we set pole pieces near the target and an electron trap in the chamber. The devices on which Al electrodes were deposited with the EB system showed almost the same properties as those of devices on which the Al electrodes were deposited by a resistive-heating method.

  4. Damage generation by electronic excitations in crystalline metals

    International Nuclear Information System (INIS)

    Dunlop, A.; Lesueur, D.

    1992-01-01

    This paper will give a rapid overview of the main experimental results concerning the effects of high electronic energy deposition in metallic targets and present a tentative model based on the Coulomb explosion mechanism. More detailed reviews have been made recently concerning both the experiments and the theoretical model. High levels of localized energy deposition in electronic excitation are easily obtained using GeV heavy ions which during their slowing-down typically transfer a few keV/A to the electronic system of the target and a few eV/A in elastic collisions with target nuclei. In insulators and organic materials, it is well-known that both slowing-down processes contribute to damage creation, whereas in metals it has been claimed for a long time that the sole nuclear collisions are involved in damage processes. Although this last assertion remains true for some metals such as Cu, Ag, W, Cu 3 Au...[2], high levels of electronic excitation can induce a partial annealing of the defects resulting from nuclear collisions in Fe, Ni, Nb, Pt..., lead to additional defect creation in Fe, Co, Zr, Ti...[2] or even to phase transformations in NiZr 2 [5], Ni 3 B [6], NiTi [7], Ti [8]... In the following, we shall only focus on the last two effects. (author). 15 refs

  5. Improvement in properties of plastic teeth by electron beam irradiation

    International Nuclear Information System (INIS)

    Sano, Yuko; Ishikawa, Shun-ichi; Seguchi, Tadao

    2011-01-01

    Improvement of the comfort and esthetics of artificial plastic teeth is desirable for the recently increasing numbers of elderly in society. Plastic teeth made of polycarbonate (PC) were modified by electron beam (EB) irradiation under specific conditions, and the change in the chemical properties of the PC was investigated. The water absorption, glucose attachment, level of bis-phenol-A (BPA) extraction, maltose adhesion, and mucin adhesion on the PC teeth were measured before and after EB irradiation. EB irradiation to a dose of 3.5 kGy at 150 o C in a nitrogen gas atmosphere reduced the water absorption by 20%, glucose absorption by 40%, maltose adhesion by 20%, and the amount of various amino acids, formed as the hydrolysis products of mucin, adhering on the PC teeth were reduced by 60-99%. The BPA content was lower than the detection limit for analysis of both the original and the EB irradiated PC teeth. - Highlights: → Radiation improvement of polycarbonate for plastic teeth by EB irradiation 3.5 kGy at 150 o C in inert gas. → Water and glucose absorption and maltose adhesion on PC teeth were much reduced. → Bis-phenol-A content from PC teeth was lower than the detection limit after irradiation.

  6. Positron lifetime measurements on electron irradiated amorphous alloys

    International Nuclear Information System (INIS)

    Moser, P.; Hautojaervi, P.; Chamberod, A.; Yli-Kauppila, J.; Van Zurk, R.

    1981-08-01

    Great advance in understanding the nature of point defects in crystalline metals has been achieved by employing positron annihilation technique. Positrons detect vacancy-type defects and the lifetime value of trapped positrons gives information on the size of submicroscopic vacancy aglomerates and microvoids. In this paper it is shown that low-temperature electron irradiations can result in a considerable increase in the positron lifetimes in various amorphous alloys because of the formation of vacancy-like defects which, in addition of the pre-existing holes, are able to trap positrons. Studied amorphous alloys were Fe 80 B 20 , Pd 80 Si 20 , Cu 50 Ti 50 , and Fe 40 Ni 40 P 14 B 6 . Electron irradiations were performed with 3 MeV electrons at 20 K to doses around 10 19 e - /cm 2 . After annealing positron lifetime spectra were measured at 77 K

  7. Investigation of the effect of some irradiation parameters on the response of various types of dosimeters to electron irradiation

    International Nuclear Information System (INIS)

    Farah, K.; Kuntz, F.; Kadri, O.; Ghedira, L.

    2004-01-01

    Several undyed and dyed polymer films are commercially available for dosimetry in intense radiation fields, especially for radiation processing of food and sterilisation of medical devices. The effects of temperature during irradiation and post-irradiation stability, on the response of these dosimeters are of importance to operators of irradiation facilities. The present study investigates the effects of temperature during irradiation by 2.2 MeV electrons beam accelerator and post irradiation storage on the response of several types of dosimeter films. All dosimeters showed a significant effect of temperature during irradiation and post-irradiation storage

  8. Investigation of the effect of some irradiation parameters on the response of various types of dosimeters to electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Farah, K. E-mail: k.farah@cnstn.rnrt.tn; Kuntz, F.; Kadri, O.; Ghedira, L

    2004-10-01

    Several undyed and dyed polymer films are commercially available for dosimetry in intense radiation fields, especially for radiation processing of food and sterilisation of medical devices. The effects of temperature during irradiation and post-irradiation stability, on the response of these dosimeters are of importance to operators of irradiation facilities. The present study investigates the effects of temperature during irradiation by 2.2 MeV electrons beam accelerator and post irradiation storage on the response of several types of dosimeter films. All dosimeters showed a significant effect of temperature during irradiation and post-irradiation storage.

  9. Study on radiation damage of electron and γ-rays and mechanism of nuclear hardening

    International Nuclear Information System (INIS)

    Jing Tao

    2001-01-01

    Radiation damage effects of electrons and γ-rays are presented. The damage defects are studied by experimental methods. On the basis of these studies the damage mechanism and nuclear hardening techniques are studied

  10. Slow elimination of DNA damaged bases in the liver of old gamma-irradiated mice

    Energy Technology Data Exchange (ETDEWEB)

    Gaziev, A I; Malakhova, L V; Fomenko, L A [AN SSSR, Pushchino-na-Oke. Inst. Biologicheskoj Fiziki

    1981-01-01

    Elimination of the DNA damaged bases in the liver of old and young mice after their gamma-irradiation is studied. It is established that the incision rate of DNA gamma-damaged bases in the liver of old mice is lower than in the liver of the young ones. It is supposed to be connected with the decrease of the activity of DNA reparation ferments or with the presence of limitations in chromatin for the access of these ferments to the damaged parts of DNA in the cells of old animals.

  11. Photoreactivable sector of lethal damage in ultraviolet-irradiated Escherichia coli cells

    International Nuclear Information System (INIS)

    Balgavy, P.

    1976-01-01

    The photoreactivable sector of lethal damage in Escherichia coli Bsub(s-1), Escherichia coli B/r Hcr - and Escherichia coli B/r Hcr + cells after ultraviolet irradiation at 254 nm is 0.823 +- 0.004, 0.70 +- 0.01 and 0.53 +- 0.06, respectively, at 99% confidence limits. For the low values of the photoreactivable sector in the B/r Hcr - and B/r Hcr + strains are likely to be responsible dark repair processes which eliminate lethal damage, brought about by pyrimidine dimers, preferably in comparison with lethal damage caused by photoproducts of another type. (author)

  12. Impacts of damage production and accumulation on materials performance in irradiation environment

    DEFF Research Database (Denmark)

    Singh, B.N.

    1998-01-01

    and needs to be extended to temperatures below stage V and to materials of practical interests. This requires, however, that the information regarding the effects of alloying elements and impurity atoms on the nature of the primary damage state are available from molecular dynamics and kinetic Monte Carlo...... the damage accumulation, irradiation hardening and the loss of ductility. The recently developed production bias model together with one-dimensional glide of interstitial clusters produced in the cascades has been shown to describe the damage accumulation at temperatures above stage V for pure metals...... type of simulations. (C) 1998 Elsevier Science B.V. All rights reserved....

  13. Effect of ammonia and electron beam irradiation on lignocelulosic materials

    International Nuclear Information System (INIS)

    Mastro, N.L. del; Gennari, S.M.; Castagnet, A.C.G.

    1986-01-01

    Reports on some of the effects produced on sugarcane bagasse and eucaliptus wood saccharification by combining irradiation and NH 3 treatment. The samples irradiated at 10 5 Gy, 2x10 5 Gy and 5x10 5 Gy with an electron accelerator were treated with anhydrous gaseous ammonia. Cellulase complex from T. reesei was used for hydrolysis assays. Bromatological analysis and 'in vitro' digestibility tests were performed. The combination of EBI and ammonia treatments produced and increase in the saccharification yield, 'in vitro' digestibility and protein content for the two kinds of sample. (Author) [pt

  14. Segregation of a copper-nickel alloy after electron irradiation

    International Nuclear Information System (INIS)

    Wagner, W.

    1979-09-01

    In the present work measurement of diffuse neutron scattering are used to determine short range segregation effects of the alloy Cu 0 sub(.) 414 Ni 0 sub(.) 586 after thermal annealing and 3 MeV electron irradiation in the temperature range between 370 K and 600 K. In addition neutron small angle scattering measurement are performed after irradiation to study possible long range segregation effects. Residual resistivity measurements are performed in parallel in order tp orientate the relatively expensive neutron scattering measurements with respect to the residual changes (orig./KBI) [de

  15. Responses and damages during long-term continuous irradiation in plants

    International Nuclear Information System (INIS)

    Watanabe, Yoshito

    2011-01-01

    Effects of long-term continuous irradiation are relevant to studies in radiation ecotoxicology. To investigate plants biological responses to continuous irradiation, we performed metabolome and transcriptome analysis in a model plant, arabidopsis. Comprehensive analysis of primary metabolites using capillary electrophoresis mass spectrometry revealed extensive metabolic changes at early onset of growth inhibition in plants exposed to gamma rays at the dose rate of 20 Gy/day. The changes included elevated levels of B vitamins and second metabolites, commonly responsive to many abiotic and biotic stresses. Responses at early onset of growth inhibition were also observed in the transcriptome analysis using microarray, which showed up-regulation of 55 genes in plants exposed to gamma rays at 20 Gy/day. Although about a half of the up-regulated genes were also responsive just after acute irradiation, the other half was responsive only during long-term continuous irradiation. Database analyses showed that the specifically up-regulated genes to long-term continuous irradiation included genes relating to general stress responses and protein metabolism. The results of these analyses appear to reflect plants responses to progressive radiation damages, from radiation-specific responses, which repair primary DNA damage, to more general stress responses, which maintain homoeostasis against secondary damages. (author)

  16. Self-irradiation damage in 4H-SiC by molecular dynamics simulation

    International Nuclear Information System (INIS)

    Han Miaomiao; Wang Qingyu; Li Taosheng; Li Zhongyu

    2014-01-01

    The development of nuclear technology is closely and inseparably related to the improvements of materials irradiation performance. The irradiation damage of nuclear materials is an important issue of characteristics and difficulties. Because of the excellent features, SiC becomes one of the candidate materials for the cladding material and structure material in fast neutron reactor and fusion reactor. As one of the polytypes, 4H-SiC has prospective important applications in a strong irradiation environment. In this work, molecular dynamics (MD) simulation was performed to study the irradiation-induced cascade damage in single-crystalline 4H-SiC to get the microscopic evolution during the irradiation, in the aim of getting access to the detail that we cannot get from experiments. The software LAMMPS was used to simulate the damage formation process and the recovery process. The results showed that the initial project direction, the temperature and PKA energy exerted significant effects on the number and morphology of defects. (authors)

  17. Potentiality of Melatonin as a Radiation Protector against Hemoglobin Damage in the Experimental Animals Due to Gamma Irradiation

    International Nuclear Information System (INIS)

    Farag, H.; Hassan, R. A.; Mohamed, Sh.

    2013-01-01

    Ionizing radiation causes serious damage in biological system. Some drugs and antioxidants are used to prevent such damage. In the present study two doses of melatonin (10 mg⁄kg and 30 mg⁄kg) were selected to be used for such purpose. The radioprotective effects of melatonin on hemoglobin of red blood cells from female mice was studied through UV absorption spectrum, ESR spectroscopy, dielectric measurements and relative viscosity .The results of Hemoglobin absorption indicate that a pronounced increase in the average value of peak position and width at half maximum W hmax followed by a decrease in the absorbance of sort band, decrease in absorption ratio A 578 / A 540 in addition to disappearance of globin band at 275 nm. The free radicals which are expected to be formed after exposing to γ-irradiation are detected by electron spin resonance spectroscopy (ESR). The results indicate that the intensity of ESR signal for hemoglobin extracted from animals exposed to γ- irradiation is greater as compared with normal hemoglobin. Dielectric measurements indicate that there is an increase in dielectric permittivity (ε‵), the dielectric loss (ε‶) and the a.c conductivity (σ ac ) while some decrease is noticed in the viscosity measurements after exposing to irradiation. The data obtained from the whole studied parameters after treating animals with melatonin become closer to those for unirradiated samples.

  18. The irradiation action on human dental tissue by X-rays and electrons. A nanoindenter study

    Energy Technology Data Exchange (ETDEWEB)

    Fraenzel, Wolfgang [Halle-Wittenberg Univ., Halle (Germany). Dept. of Physics; Gerlach, Reinhard [Halle-Wittenberg Univ., Halle (Germany). Clinic of Radiation Therapy

    2009-07-01

    It is known that ionizing radiation is used in medicine for Roentgen diagnostics and for radiation therapy. The radiation interacts with matter, in particular with biological one, essentially by scattering, photoelectric effect, Compton effect and pair production. To what extent the biological material is changed thereby, depends on the type and the amount of radiation energy, on the dose and on the tissue constitution. In modern radiation therapy two different kinds of radiation are used: high energy X-rays and electron radiation. In the case of head-neck tumors the general practice is an irradiation with high energy X-rays with absorbed dose to water up to 70 Gy. Teeth destruction has been identified as a side effect during irradiation. In addition, damage to the salivary glands is often observed which leads to a decrease or even the complete loss of the salivary secretion (xerostomia). This study shows how the different energy and radiation types damage the tooth tissue. The effects of both, high X-ray energy and high energy electrons, on the mechanical properties hardness and elasticity of the human dental tissue are measured by the nanoindentation technique. We compare these results with the effect of the irradiation of low X-ray energy on the dental tissue. (orig.)

  19. The irradiation action on human dental tissue by X-rays and electrons. A nanoindenter study

    International Nuclear Information System (INIS)

    Fraenzel, Wolfgang; Gerlach, Reinhard

    2009-01-01

    It is known that ionizing radiation is used in medicine for Roentgen diagnostics and for radiation therapy. The radiation interacts with matter, in particular with biological one, essentially by scattering, photoelectric effect, Compton effect and pair production. To what extent the biological material is changed thereby, depends on the type and the amount of radiation energy, on the dose and on the tissue constitution. In modern radiation therapy two different kinds of radiation are used: high energy X-rays and electron radiation. In the case of head-neck tumors the general practice is an irradiation with high energy X-rays with absorbed dose to water up to 70 Gy. Teeth destruction has been identified as a side effect during irradiation. In addition, damage to the salivary glands is often observed which leads to a decrease or even the complete loss of the salivary secretion (xerostomia). This study shows how the different energy and radiation types damage the tooth tissue. The effects of both, high X-ray energy and high energy electrons, on the mechanical properties hardness and elasticity of the human dental tissue are measured by the nanoindentation technique. We compare these results with the effect of the irradiation of low X-ray energy on the dental tissue. (orig.)

  20. Evaluation of radio-protective effect of melatonin on whole body irradiation induced liver tissue damage.

    Science.gov (United States)

    Shirazi, Alireza; Mihandoost, Ehsan; Ghobadi, Ghazale; Mohseni, Mehran; Ghazi-Khansari, Mahmoud

    2013-01-01

    Ionizing radiation interacts with biological systems to induce excessive fluxes of free radicals that attack various cellular components. Melatonin has been shown to be a direct free radical scavenger and indirect antioxidant via its stimulatory actions on the antioxidant system.The aim of this study was to evaluate the antioxidant role of melatonin against radiation-induced oxidative injury to the rat liver after whole body irradiation. In this experimental study,thirty-two rats were divided into four groups. Group 1 was the control group, group 2 only received melatonin (30 mg/kg on the first day and 30 mg/kg on the following days), group 3 only received whole body gamma irradiation of 10 Gy, and group 4 received 30 mg/kg melatonin 30 minutes prior to radiation plus whole body irradiation of 10 Gy plus 30 mg/kg melatonin daily through intraperitoneal (IP) injection for three days after irradiation. Three days after irradiation, all rats were sacrificed and their livers were excised to measure the biochemical parameters malondialdehyde (MDA) and glutathione (GSH). Each data point represents mean ± standard error on the mean (SEM) of at least eight animals per group. A one-way analysis of variance (ANOVA) was performed to compare different groups, followed by Tukey's multiple comparison tests (p<0.05). The results demonstrated that whole body irradiation induced liver tissue damage by increasing MDA levels and decreasing GSH levels. Hepatic MDA levels in irradiated rats that were treated with melatonin (30 mg/kg) were significantly decreased, while GSH levels were significantly increased, when compared to either of the control groups or the melatonin only group. The data suggest that administration of melatonin before and after irradiation may reduce liver damage caused by gamma irradiation.

  1. Ionization versus displacement damage effects in proton irradiated CMOS sensors manufactured in deep submicron process

    International Nuclear Information System (INIS)

    Goiffon, V.; Magnan, P.; Saint-Pe, O.; Bernard, F.; Rolland, G.

    2009-01-01

    Proton irradiation effects have been studied on CMOS image sensors manufactured in a 0.18μm technology dedicated to imaging. The ionizing dose and displacement damage effects were discriminated and localized thanks to 60 Co irradiations and large photodiode reverse current measurements. The only degradation observed was a photodiode dark current increase. It was found that ionizing dose effects dominate this rise by inducing generation centers at the interface between shallow trench isolations and depleted silicon regions. Displacement damages are is responsible for a large degradation of dark current non-uniformity. This work suggests that designing a photodiode tolerant to ionizing radiation can mitigate an important part of proton irradiation effects.

  2. Genotoxic damage in non-irradiated cells: contribution from the bystander effect

    International Nuclear Information System (INIS)

    Zhou, H.; Randers-Pherson, G.; Suzuki, M.; Waldren, C.A.; Hei, T.K.

    2002-01-01

    It has always been accepted dogma that the deleterious effects of ionising radiation such as mutagenesis and carcinogenesis are due mainly to direct damage to DNA. Using the Columbia University charged-particle microbeam and the highly sensitive A L cell mutagenic assay, it is shown here that non-irradiated cells acquire the mutagenic phenotype through direct contact with cells whose nuclei are traversed with 2 alpha particles each. Pre-treatment of cells with lindane, a gap junction inhibitor, significantly decreased the mutant yield. Furthermore, when irradiated cells were mixed with control cells in a similar ration as the in situ studies, no enhancement in bystander mutagenesis was detected. Our studies provide clear evidence that genotoxic damage can be induced in non-irradiated cells, and that gap junction mediated cell-cell communication plays a critical role in the bystander phenomenon. (author)

  3. Analysis of WWER-440 and PWR RPV welds surveillance data to compare irradiation damage evolution

    Energy Technology Data Exchange (ETDEWEB)

    Debarberis, L. [Joint Research Centre of the European Commission, Institute for Energy, P.O. Box 2, 1755 ZG Petten (Netherlands)]. E-mail: luigi.debarberis@cec.eu.int; Acosta, B. [Joint Research Centre of the European Commission, Institute for Energy, P.O. Box 2, 1755 ZG Petten (Netherlands)]. E-mail: beatriz.acosta-iborra@jrc.nl; Zeman, A. [Joint Research Centre of the European Commission, Institute for Energy, P.O. Box 2, 1755 ZG Petten (Netherlands); Sevini, F. [Joint Research Centre of the European Commission, Institute for Energy, P.O. Box 2, 1755 ZG Petten (Netherlands); Ballesteros, A. [Tecnatom, Avd. Montes de Oca 1, San Sebasitan de los Reyes, E-28709 Madrid (Spain); Kryukov, A. [Russian Research Centre Kurchatov Institute, Kurchatov Square 1, 123182 Moscow (Russian Federation); Gillemot, F. [AEKI Atomic Research Institute, Konkoly Thege M. ut 29-33, 1121 Budapest (Hungary); Brumovsky, M. [NRI, Nuclear Research Institute, Husinec-Rez 130, 25068 Rez (Czech Republic)

    2006-04-15

    It is known that for Russian-type and Western water reactor pressure vessel steels there is a similar degradation in mechanical properties during equivalent neutron irradiation. Available surveillance results from WWER and PWR vessels are used in this article to compare irradiation damage evolution for the different reactor pressure vessel welds. The analysis is done through the semi-mechanistic model for radiation embrittlement developed by JRC-IE. Consistency analysis with BWR vessel materials and model alloys has also been performed within this study. Globally the two families of studied materials follow similar trends regarding the evolution of irradiation damage. Moreover in the high fluence range typical of operation of WWER the radiation stability of these vessels is greater than the foreseen one for PWR.

  4. The application analysis of high energy electron accelerator in food irradiation processing

    International Nuclear Information System (INIS)

    Deng Wenmin; Chen Hao; Feng Lei; Zhang Yaqun; Chen Xun; Li Wenjun; Xiang Chengfen; Pei Ying; Wang Zhidong

    2012-01-01

    Irradiation technology of high energy electron accelerator has been highly concerned in food processing industry with its fast development, especially in the field of food irradiation processing. In this paper, equipment and research situation of high energy electron accelerator were collected, meanwhile, the similarities and differences between high energy electron beam and 60 Co γ-rays were discussed. In order to provide more references of high energy electron beam irradiation, the usages of high energy electron in food irradiation processing was prospected. These information would promote the development of domestic food irradiation industry and give a useful message to irradiation enterprises and researchers. (authors)

  5. Surface damage and gas trapping profile measurements in copper during 20 kev He+ irradiation

    International Nuclear Information System (INIS)

    Terreault, B.; Veilleux, G.

    1980-01-01

    Surface damage due to 20 keV he + irradiation of OFHC Cu was studied by optical and scanning electron microscopy, and by gas trapping profile measurements with proton backscattering and elastic recoil detection. Both annealed (1 h at 773 K) and unannealed Cu were implanted, at 300 K (0.22Tsub(m)) and 500 K(0.37 Tsub(m)), up to fluences of 3 x 10 18 cm -2 . Additional results with thin (1 μm) evaporated films and stressed cold-rolled foils (3 μm) were obtained. At 500 K in bulk OFHC Cu pores and/or large (approx. 1μm) but scattered blisters appear; at 300 K in bulk or thin film Cu blisters are large and abundant. In all these cases a very large (>=1.5 x 10 1 7 cm -2 ) and sudden release of deeply implanted helium takes place, leading to a depleted profile at a depth of about 90 nm (approx. Rsub(p)). In contrast in cold-rolled foils the blisters are small (approx. 0.4 μm) and the profiles are undepleted. These results are explained by fissuration of helium-pressurized cavities. At high fluence blisters disappear, leaving a porous structure at 500 K and a rough micro-relief at 300 K; the helim profiles are flat and very wide (2-3 Rsub(p)). Blister disappearance, absence of flaking, and porous structure are discussed in terms of the width of the profiles and the formation of a helium-saturated, highly damaged (recrystallized), and permeable layer. (orig.)

  6. Electron microbeam specifications for use in cell irradiation experiments

    International Nuclear Information System (INIS)

    Kim, E.-H.; Choi, M.-C.; Lee, D.-H.; Chang, M.; Kang, C.-S.

    2003-01-01

    The microbeam irradiation system was devised originally to identify the hit and unhit cells by confining the beam within the target cell. The major achievement through the microbeam experiment studies has turned out to be the discovery of the 'bystander effect'. Microbeam experiments have been performed with alpha and proton beams in major and with soft x-rays in minor. The study with electron microbeam has been deferred mainly due to the difficulty in confining the electron tracks within a single target cell. In this paper, the electron microbeam irradiation system under development in Korea is introduced in terms of the beam specifications. The KIRAMS electron microbeam irradiation system consists of an electron gun, a vacuum chamber for beam collimation into 5 μm in diameter and a biology stage. The beam characteristics in terms of current and energy spectrum of the electrons entering a target cell and its neighbor cells were investigated by Monte Carlo simulation for the electron source energies of 25, 50, 75 and 100 keV. Energy depositions in the target cell and the neighbor cells were also calculated. The beam attenuation in current and energy occurs while electrons pass through the 2 μm-thick Mylar vacuum window, 100 μm-thick air gap and the 2 μm-thick Mylar bottom of cell dish. With 25 keV electron source, 80 % of decrease in current and 30 % of decrease in average energy were estimated before entering the target cell. With 75 keV electron source, on the other hand, 55 % of decrease in current and less than 1 % of decrease in average energy were estimated. Average dose per single collimated electron emission was 0.067 cGy to the target cell nucleus of 5 μm in diameter and 0.030 cGy to the cytoplasm of 2.5 μm in thickness with 25 keV electron source while they were 0.15 cGy and 0.019 cGy, respectively, with 75 keV electron source. The multiple scattering of electrons resulted in energy deposition in the neighbor cells as well. Dose to the first

  7. Biological significance of the focus on DNA damage checkpoint factors remained after irradiation of ionizing radiation

    International Nuclear Information System (INIS)

    Yamauchi, Motohiro; Suzuki, Keiji

    2005-01-01

    This paper reviews recent reports on the focus formation and participation to checkpoint of (such phosphorylated (P-d) as below) ATM and H2AX, MDC1, 53BP1 and NBS1, and discusses their role in DNA damage checkpoint induction mainly around authors' studies. When the cell is irradiated by ionizing radiation, the subtype histone like H2AX is P-d and the formed focus', seen in the nucleus on immuno-fluorographic observation, represents the P-d H2AX at the damaged site of DNA. The role of P-d ATM (the product of causative gene of ataxia-telangiectasia mutation, a protein kinase) has been first shown by laser beam irradiation. Described are discussions on the roles and functions after irradiation in focus formation and DNA damage checkpoint of P-d H2AX (a specific histone product by the radiation like γ-ray as above), P-d ATM, MDC1 (a mediator of DNA damage check point protein 1), 53BP1, (a p53 binding protein) and NBS1 (the product of the causative gene of Nijmegen Breakage Syndrome). Authors have come to point out the remained focal size increase as implications of the efficient repair of damaged DNA, and the second cycled p53 accumulation, of tumor suppression. Thus evaluation of biological significance of these aspects, scarcely noted hitherto, is concluded important. (S.I.)

  8. Arrest of irradiated G1, S, or G2 cells at mitosis using nocodazole promotes repair of potentially lethal damage

    International Nuclear Information System (INIS)

    Iliakis, G.; Nuesse, M.

    1984-01-01

    The ability of synchronized Ehrlich ascites tumor cells, irradiated in G1, S, and G2 phases, to repair potentially lethal damage when arrested at mitosis by using 0.4 μg/ml nocodazole, a specific inhibitor of microtubule polymerization, has been studied. Cells irradiated in these phases were found to repair potentially lethal damage at mitosis. The extent of this repair was similar to that observed for cells irradiated at the same stages in the cell cycle but allowed to repair potentially lethal damage by incubating in balanced salt solution for 6 hr after X irradiation

  9. Plastic coating on paper by electron beam irradiation

    International Nuclear Information System (INIS)

    Ametani, Kazuo; Tsuchiya, Mitsuaki; Sawai, Takeshi

    1984-01-01

    It has been known long since that the resin system of unsaturated polyester and vinylmonomer mixture cures by irradiation. Ford of USA for the first time industrialized the radiation curing reaction of resins for the coating of automobile parts. Thereafter, accompanying the development and technical advance of the low energy electron beam irradiation apparatus which is suitable to surface treatment such as coating and easy to handle and the development of resins, the electron beam curing method has become to be utilized for coating hardboard and wooden doors, coating automobile tire rims, adhering printing papers and others. The electron beam curing method has advantage such as energy conservation, resource saving and little pollution because solvent is not used, high production rate and small floor space. In glossing industry, for the purpose of developing the techniques to apply electron beam curing method to glazed paper production, the selection of the composition of resins suitable to glazed papers, the irradiating condition and the properties of cured films were examined. The films withstanding bending can be obtained at low dose with urethane group, ester group or the combination of monomers. (Kako, I.)

  10. Quantitative analysis of complexes in electron irradiated CZ silicon

    International Nuclear Information System (INIS)

    Inoue, N.; Ohyama, H.; Goto, Y.; Sugiyama, T.

    2007-01-01

    Complexes in helium or electron irradiated silicon are quantitatively analyzed by highly sensitive and accurate infrared (IR) absorption spectroscopy. Carbon concentration (1x10 15 -1x10 17 cm -3 ) and helium dose (5x10 12 -5x10 13 cm -2 ) or electron dose (1x10 15 -1x10 17 cm -2 ) are changed by two orders of magnitude in relatively low regime compared to the previous works. It is demonstrated that the carbon-related complex in low carbon concentration silicon of commercial grade with low electron dose can be detected clearly. Concentration of these complexes is estimated. It is clarified that the complex configuration and thermal behavior in low carbon and low dose samples is simple and almost confined within the individual complex family compared to those in high concentration and high dose samples. Well-established complex behavior in electron-irradiated sample is compared to that in He-irradiated samples, obtained by deep level transient spectroscopy (DLTS) or cathodoluminescence (CL), which had close relation to the Si power device performance

  11. Radiation defects in electron-irradiated InP crystals

    Energy Technology Data Exchange (ETDEWEB)

    Brailovskii, E.Yu.; Karapetyan, F.K.; Megela, I.G.; Tartachnik, V.P. (AN Ukrainskoj SSR, Kiev. Inst. Yadernykh Issledovanij)

    1982-06-16

    The results are presented of formation and annealing of defects in InP crystals at 1 to 50 MeV electron irradiation. The recovery of electrical properties in the range of 77 to 970 K during annealing processes is studied. Five low temperature annealing states in n-InP and the reverse annealing in p-InP are observed at 77 to 300 K. Four annealing stages at temperatures higher than 300 K are present. When the electron energy is increased more complicated thermostable defects are formed, and at 50 MeV electron energy besides of the point defect clusters are formed, which anneal at temperatures of 800 to 970 K. It is shown that the peculiarities of the Hall mobility at irradiation and annealing are caused by the scattering centres E/sub c/ - 0.2 eV. The 'limiting' position of the Fermi level in electron irradiated InP crystals is discussed.

  12. DOMPAC dosimetry experiment. Neutronic simulation of the thickness of a PWR pressure vessel. Irradiation damages

    International Nuclear Information System (INIS)

    Alberman, A.; Faure, M.; Thierry, M.; Hoclet, O.; Le Dieu de Ville, A.; Nimal, J.C.; Soulat, P.

    1979-01-01

    For suitable extrapolation of irradiated PWR ferritic steel results, proper irradiation of the pressure vessel has been 'simulated' in test reactor. For this purpose, a huge steel block (20 cm in depth) was loaded with Saclay's graphite (GAMIN) and tungsten damage detectors. Core-block water gap was optimized through spectrum indexes method, by ANISN and SABINE codes so that spectrum in 1/4 thickness matches with ANISN computations for PWR Fessenheim 1. A good experimental agreement is found with calculated dpa damage gradient. 3D Monte Carlo computation (TRIPOLI), was performed on the DOMPAC device, and spectrum indexes evolution was found consistent with experimental results. Surveillance rigs behind a 'thermal shield' were also simulated, including damage and activation monitors. Dosimetry results give an order of magnitude of accuracies involved in projecting steel sample embrittlement to the pressure vessel [fr

  13. A structure development in electron-irradiated type Ia diamond

    International Nuclear Information System (INIS)

    Novikov, N.V.; Ositinskaya, T.D.; Tkach, V.N.

    1998-01-01

    A type Ia diamond crystal with nitrogen impurity in different forms was irradiated by 3.5 MeV electrons with increasing doses 5 centre dot 10 16 , 2 centre dot 10 17 , 4 centre dot 10 17 , 2 centre dot 10 18 e/cm 2 and investigated before and after each dose by positron annihilation, EPR, and optical spectroscopy. After irradiation with the highest dose, the effect of development of a visible defective structure of the crystal is revealed. A description of this effect and data of EPR and IR-measurements depending on irradiation doses are presented. First results of cathodoluminescence (CL) studies in the form CL-topograms and CL-spectra for difference zones of the crystal are also given

  14. Improvement of carbon fiber surface properties using electron beam irradiation

    International Nuclear Information System (INIS)

    Pino, E.S.; Machado, L.D.B.; Giovedi, C.

    2007-01-01

    Carbon fiber-reinforced advance composites have been used for structural applications, mainly on account of their mechanical properties. The main factor for a good mechanical performance of carbon fiber-reinforced composite is the interfacial interaction between its components, which are carbon fiber and polymeric matrix. The aim of this study is to improve the surface properties of the carbon fiber using ionizing radiation from an electron beam to obtain better adhesion properties in the resultant composite. EB radiation was applied on the carbon fiber itself before preparing test specimens for the mechanical tests. Experimental results showed that EB irradiation improved the tensile strength of carbon fiber samples. The maximum value in tensile strength was reached using doses of about 250 kGy. After breakage, the morphology aspect of the tensile specimens prepared with irradiated and non-irradiated car- bon fibers were evaluated. SEM micrographs showed modifications on the carbon fiber surface. (authors)

  15. Tailoring crystallinity and configuration of silica nanotubes by electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, Tomitsugu, E-mail: taguchi.tomitsugu@jaea.go.jp; Yamaguchi, Kenji

    2015-05-01

    Highlights: •Single-crystal SiO{sub 2} nanotubes were successfully synthesized for the first time. •The single-crystal SiO{sub 2} was α-crystobalite. •Desired area of single-crystal nanotube can be changed to amorphous by electron irradiation. •The configuration of nanotube can be controlled using the focused electron irradiation technique. -- Abstract: SiO{sub 2} nanotubes show potential in applications such as nanoscale electronic and optical devices, bioseparation, biocatalysis, and nanomedicine. As-grown SiO{sub 2} nanotubes in the previous studies always have an amorphous wall, and here we demonstrate the successful synthesis of single-crystal nanotubes for the first time by the heat treatment of SiC nanotubes at 1300 °C for 10 h under low-vacuum conditions. According to TEM observations, the single-crystal SiO{sub 2} was α-cristobalite. We also demonstrate that single-crystal SiO{sub 2} nanotubes can be transformed into amorphous SiO{sub 2} nanotubes by electron beam irradiation. Moreover, we synthesized a crystalline/amorphous SiO{sub 2} composite nanotube, in which crystalline and amorphous SiO{sub 2} coexisted in different localized regions. In addition, for biomedical applications such as drug delivery systems, controlling the configuration of the open end, the diameter, and capsulation of SiO{sub 2} nanotubes is crucial. We can also obturate, capsulate, and cut a SiO{sub 2} nanotube, as well as modify the inner diameter of the nanotube at a specific, nanometer-sized region using the focused electron beam irradiation technique.

  16. Defect creation rates in CdTe irradiated by electrons

    International Nuclear Information System (INIS)

    Caillot, M.

    1978-01-01

    Up to now, the defect creation rates in CdTe irradiated by electrons were unknown. They have been calculated for different electron kinetic energies. As the samples studied are thick, the energy loss when the electrons penetrate the material has been taken into account. The cross-sections of Cd and Te displacements vs the depth of electron penetration were determined for different electron kinetic energies, and the defect creation rates obtained for each sublattice. These creation rates have been compared with those deduced from experiments and it was found that the experimental creation rates were lower than the calculated ones. This discrepancy can be explained in terms of creation of neutral Frenkel pairs. (Auth.)

  17. Dislocation climb and interstitial loop growth under cascade damage irradiation

    International Nuclear Information System (INIS)

    Woo, C.H.; Semenov, A.A.

    1993-01-01

    The effects of intracascade clustering and recombination in radiation damage have been considered previously in semiquantitative calculations involving vacancy accumulation at voids, within the concept of production bias. To model void swelling and microstructural evolution quantitatively, similar effects on dislocation climb and interstitial loop growth have to be considered. In this regard, at elevated temperatures (such as in the peak-swelling temperature regime), the concentration of freely migrating vacancies is much higher than that of the interstitials, owing to the evaporation from the primary vacancy clusters (i.e. those produced by intracascade clustering). It is not immediately obvious how the dislocations can be net interstitials sinks, and hence that the observed nucleation and growth of the interstitial loops at elevated temperatures can be correctly predicted as in the conventional theory. To address these basic questions, a rate theory model is formulated in this paper, which describes the dislocation climb and loop growth in the presence of intracascade primary clusters. Within this model, conservation equations for the concentrations and average radii of the two kinds of primary cluster are derived, and the corresponding steady-state concentrations and average radii are calculated. From this, the dislocation climb velocity and interstitial loop growth rate are calculated. On the basis of the results of this calculation, some of the basic questions of production bias are discussed. (Author)

  18. Direct round window membrane application of dexamethasone in the protection of the guinea pigs'cochlea against irradiation damage

    International Nuclear Information System (INIS)

    Li Ying; Guo GuangWei; Su Jiping

    2009-01-01

    Objective: To investigate the protective effect of dexamethasone applied to round window membrane (RWM) against radiation-induced inner ear damage in guinea pigs, in order to provide the evidence for preventing and treating radiation-induced inner ear damage. Methods: 130 guinea pigs were randomly divided into four groups. (1) Dexamethasone group( n = 45): The guinea pigs were injected with dexamethasone through an intact RWM on right ear for one time after being treated with 70 Gy 60 Co γ irradiation. (2) Irradiation group(n = 45) : The guinea pigs were treated with 70 Gy 60 Co γ irradiation. (3) Saline group (n = 30): Applying of normal saline through an intact RWM on right ear for one time after being treated with 70 Gy 60 Co γ irradiation. (4) Control group(n =45) : Auditory brainstem response (ABR) was tested before the 3 rd day, the second week and the second month after irradiation (treatment) in the first three groups. The animals were sacrificed right after the ABR test and the middle ear mucosa was observed simultaneously. The hair cells were observed by surface preparation of the basilar membrane and scanning electron microscope ( SEM). Results: The normal ABR threshold is (8.2 ± 2.8) dB. The ABR thresholds increased in those of the three groups treated with irradiation and were rising with time. At the 3rd day, the second week and the second month, ABR thresholds of the dexamethasone group were (24.0 ± 14.1), (27.1 ± 9.9) and (38.0 ± 15.1) dB, respectively, while the irradiation group were (24.5 ± 13.5), (39.5 ± 15.4) and (57.2 ± 18.4) dB. The saline group were (27.0 ± 14.6) and (42.8 ± 13.5) dB, respectively. ABR thresholds of the dexamethasone group at the second week and the second month both decreased compared with those of the irradiation group and saline group ( P < 0.05) . In the control group, the outer hair cell lost by 8.0 ± 2.7 and inner hair cell by 3.7 ± 1.2. The lost quantities of the inner hair cells and outer hair cells

  19. Irradiation of aluminium alloy materials with electron beam

    International Nuclear Information System (INIS)

    Konno, Osamu; Masumoto, Kazuyoshi

    1982-01-01

    It is a theme with a room for discussion to employ the stainless steel composed of longer half-life materials for the vacuum system of accelerators, from the viewpoint of radiation exposure. Therefore, it is desirable to use aluminium of shorter half-life in place of stainless steel. As a result of investigation on the above theme in the 1.2 GeV electron linac project in Tohoku University, it has been concluded that aluminium alloy vacuum chambers can reduce exposure dose by about one or two figures as compared with stainless steel ones. Of course, aluminium alloy contains trace amounts of Mg, Si, Ti, Cr, Mn, Fe, Zn, Cu and others. Therefore, four kinds of aluminium alloy considered to be usable have been examined for induced radioactivity by electron beam irradiation. Stainless steel SUS 304 has been also irradiated for comparison. Radiation energy has been 30 MeV and 200 MeV. When stainless steel and aluminium alloy were compared, aluminium alloy was very effective for reducing surface dose in low energy irradiation. In 200 MeV irradiation, the dose ratio of aluminium alloy to stainless steel became 1/30 to 1/100 after one week, though the dose difference between these two materials became smaller in 100 days or more after irradiation. If practical inspection and repair are implemented during the period from a few days to one week after shutdown, the aluminium alloy is preferable for exposure dose reduction even in high energy irradiation. (Wakatsuki, Y.)

  20. A permanent magnet electron beam spread system used for a low energy electron irradiation accelerator

    International Nuclear Information System (INIS)

    Huang Jiang; Xiong Yongqian; Chen Dezhi; Liu Kaifeng; Yang Jun; Li Dong; Yu Tiaoqin; Fan Mingwu; Yang Bo

    2014-01-01

    The development of irradiation processing industry brings about various types of irradiation objects and expands the irradiation requirements for better uniformity and larger areas. This paper proposes an innovative design of a permanent magnet electron beam spread system. By clarifying its operation principles, the author verifies the feasibility of its application in irradiation accelerators for industrial use with the examples of its application in electron accelerators with energy ranging from 300 keV to 1 MeV. Based on the finite element analyses of electromagnetic fields and the charged particle dynamics, the author also conducts a simulation of electron dynamics in magnetic field on a computer. The results indicate that compared with the traditional electron beam scanning system, this system boosts the advantages of a larger spread area, non-power supply, simple structure and low cost, etc., which means it is not only suitable for the irradiation of objects with the shape of tubes, strips and panels, but can also achieve a desirable irradiation performance on irregular constructed objects of large size. (authors)

  1. Study on DNA Damage Induced by Neon Beam Irradiation in Saccharomyces Cerevisiae

    International Nuclear Information System (INIS)

    Lu Dong; Li Wenjian; Wu Xin; Wang Jufang; Ma Shuang; Liu Qingfang; He Jinyu; Jing Xigang; Ding Nan; Dai Zhongying; Zhou Jianping

    2010-01-01

    Yeast strain Saccharomyces cerevisiae was irradiated with different doses of 85 MeV/u 20 Ne 10+ to investigate DNA damage induced by heavy ion beam in eukaryotic microorganism. The survival rate, DNA double strand breaks (DSBs) and DNA polymorphic were tested after irradiation. The results showed that there were substantial differences in DNA between the control and irradiated samples. At the dose of 40 Gy, the yeast cell survival rate approached 50%, DNA double-strand breaks were barely detectable, and significant DNA polymorphism was observed. The alcohol dehydrogenase II gene was amplified and sequenced. It was observed that base changes in the mutant were mainly transversions of T→G and T→C. It can be concluded that heavy ion beam irradiation can lead to change in single gene and may be an effective way to induce mutation.

  2. Study on DNA Damage Induced by Neon Beam Irradiation in Saccharomyces Cerevisiae

    Science.gov (United States)

    Lu, Dong; Li, Wenjian; Wu, Xin; Wang, Jufang; Ma, Shuang; Liu, Qingfang; He, Jinyu; Jing, Xigang; Ding, Nan; Dai, Zhongying; Zhou, Jianping

    2010-12-01

    Yeast strain Saccharomyces cerevisiae was irradiated with different doses of 85 MeV/u 20Ne10+ to investigate DNA damage induced by heavy ion beam in eukaryotic microorganism. The survival rate, DNA double strand breaks (DSBs) and DNA polymorphic were tested after irradiation. The results showed that there were substantial differences in DNA between the control and irradiated samples. At the dose of 40 Gy, the yeast cell survival rate approached 50%, DNA double-strand breaks were barely detectable, and significant DNA polymorphism was observed. The alcohol dehydrogenase II gene was amplified and sequenced. It was observed that base changes in the mutant were mainly transversions of T→G and T→C. It can be concluded that heavy ion beam irradiation can lead to change in single gene and may be an effective way to induce mutation.

  3. Effect of electron-beams irradiation for inactivation of microorganisms on spices

    International Nuclear Information System (INIS)

    Ito, Hitoshi; Islam, Md.S.

    1993-01-01

    Total aerobic bacteria in spices used in this study were determined to be 1x10 6 to 6x10 7 per gram. A study on the inactivation of microorganisms in spices showed that doses of 6 to 9 kGy of EB (electron-beams) or gamma irradiation were required to reduce the total aerobic bacteria tobelow 10 3 per gram. However, a little increase of resistance was observed on the inactivation of total aerobic bacteria in many spices in case of EB irradiation. These difference of radiation sensitivities between EB and gamma-rays was explained by dose rate effect on oxidation damage to microorganisms from the results of radiation sensitivities of Bacillus pumilus and B. megaterium spores at dry conditions. On the other hand, these high dose rate of EB irradiation suppressed the increase of peroxide values in spices at high dose irradiation up to 80 kGy. Components of essential oils in spices were not changed even irradiated up to 50 kGy with EB and gamma-rays. (author)

  4. Detection of electron beam irradiated crude drugs by electron spin resonance (ESR)

    International Nuclear Information System (INIS)

    Yamaoki, Rumi; Kimura, Shojiro; Aoki, Kenji; Nishimoto, Susumu

    2007-01-01

    Perillae Herba, Sennae Folium, Cinnamomi Cortex, Phellodendri Cortex, Ginseng Radix, Glycyrrhizae Radix, Paeoniae Radix, and Zingiberis Rhizoma were irradiated with electron beam (5 MeV) and organic radicals were detected by ESR measurement, before and after irradiation (10 kGy). A single line spectrum was detected at around g=2.005 in non-irradiated crude drugs, and radical concentrations were high in the leaf varieties of crude drugs. After irradiation, the signal intensity around g=2.005 increased, and a new subsignal was detected as a 3 mT shoulder of this signal. Broad, asymmetrically divided signals were also detected in irradiated root varieties of crude drugs. The free radical localized on the organic components of irradiated crude drugs tended to decrease with the water content. After irradiation, signal intensity reduced and reached a steady state after about 1 to 2 months. However, specificity of the ESR signal shape appearing after irradiation continued to be detectable for 6 months in leaf varieties and for a year in bark and root varieties of crude drugs. Consequently, it was concluded that ESR could be applied as an initial screening procedure to detect irradiated crude drugs. (author)

  5. Color formation study of irradiated polymers by electron beam

    International Nuclear Information System (INIS)

    Nardi, Daniela Teves

    2004-01-01

    Color formation on national and commercial polymers (polymethyl methacrylate, polystyrene and polycarbonate) irradiated by electrons beam was investigated by colorimetry (CIELab), electron spectroscopy resonance (ESR), photoacoustic infrared spectroscopy (FTIR-PAS) and differential exploratory calorimetry (DSC). The heat effect on colorimetric properties was investigated after heating (110 deg C for 1 hour) of irradiated polymers at 150 kGy. The rule of oxygen in colorimetric properties of irradiated polycarbonate was investigated in the air presence and absence (p = 10 -3 mmHg). The visual aspect did not agree with colorimetric parameters only for polycarbonate. Yellow color and darkness were induced by radiation for all studied polymers varying only the intensity and behavior in function of post-irradiation time and heating. Polymethyl methacrylate and polystyrene ESR spectra showed that radicals could be responsible by yellow color centers. Wherever, in polycarbonate, color centers were not due radical species. The nature of color centers for any studied polymer was not study by FTIR-PAS because there were no changes in FTIR-PAS spectra neither in function of dose nor heating. Polycarbonate was the most radiosensible and polystyrene was the most radioresistant of all studied polymers in concern of colorimetric properties. (author)

  6. Improvement of carbon fibre surface properties using electron beam irradiation

    International Nuclear Information System (INIS)

    Eddy Segura Pino; Luci Diva Brocardo Machado; Claudia Giovedi

    2006-01-01

    Carbon fiber-reinforced advance composites have been used for structural applications, mainly due to their mechanical properties, and additional features such as high strength-to-weight ratio, stiffness-to-weight ratio, corrosion resistance and wear properties. The main factor for a good mechanical performance of carbon fiber-reinforced composite is the interfacial interaction between the components that are fiber and polymeric matrix. The greatest challenge is to improve adhesion between components having elasticity modulus which differ by orders of magnitude and furthermore they are immiscible in each other. Another important factor is the sizing material on the carbon fiber, which protects the carbon fiber filaments and must be compatible with the matrix material in order to improve the adhesion process. The interaction of ionizing radiation from electron beam can induce in the irradiated material the formation of very active centers and free radicals. Further evolution of these active species can significantly modify structure and properties not only in the irradiated polymeric matrix but also on the fiber surface. So that, fiber and matrix play an important role in the production of chemical bonds, which promote better adhesion between both materials improving the composite mechanical performance. The aim of this work was to improve the surface properties of the carbon fiber surface using ionizing radiation from an electron beam in order to obtain improvement of the adhesion properties in the resulted composite. Commercial carbon fiber roving of high tensile strength with 12 000 filaments named 12 k, and sizing material of epoxy resin modified by ester groups was studied. EB irradiation has been carried out at the Institute for Nuclear and Energy Research (IPEN) facilities using a 1.5 MeV 37.5 kW Dynamitron electron accelerator model JOB-188. Rovings of carbon fibers with 1.78 g cm -3 density and 0.13 mm thickness were irradiated with 0.555 MeV, 6.43 mA and

  7. [Protective Effect of S-isopentenyl-L-cysteine against DNA Damage in Irradiated Mice].

    Science.gov (United States)

    Zheng, Qi-sheng; Yu, Guang-yun; He, Xin; Jiang, Ming; Chu, Xiao-fei; Zhao, Shu-yi; Fan, Sai-jun; Liu, Pei-xun

    2015-10-01

    To evaluate the protective effect of S-isopentenyl-L-cysteine,a new cysteine derivative,on DNA damage induced by radiation by using acute radiation injury animal models. Forty ICR mice were randomly divided into five groups:the control group,1.0Gy gamma irradiation group,1.0Gy gamma irradiation combined with S-isopentenyl-L-cysteine group,7.2Gy gamma irradiation group,and 7.2Gy gamma irradiation combined with S-isopentenyl-L-cysteine group,with 8 mice in each group.The comet assay and bone marrow polychromatic micronucleus experiments were performed to evaluate the double-strand DNA breaks in ICR mice exposed to 1.0 and 7.2Gy gamma-ray, respectively. The tail DNA percentage,tail length,tail moment,and olive tail moment of peripheral blood lymphocytes in 7.2Gy gamma irradiation group were significantly higher than that of the control group (PL-cysteine group was significantly less than that of 7.2Gy gamma irradiation group (PL-cysteine before irradiation,the micronucleus rate of ICR mice exposed to 1.0 and 7.2Gy gamma-ray decreased from (39.5000 ± 3.3141)‰ to (28.1667±4.1345)‰ (P=0.033) and from (76.5000 ± 4.6242)‰ to (22.8333 ± 3.6553)‰(P=0.000),respectively. The bone marrow polychromatic micronucleus experiment indicated that the value of polychromatic erythrocyte (PCE)/normochromatic erythrocyte(NCE) of ICR mice exposed to 1.0 and 7.2Gy gamma-ray was less than the control group(PL-cysteine before irradiation was significantly higher than the corresponding groups (PL-cysteine has a good protective effect against DNA damage induced by radiation.

  8. Defects in low temperature electron irradiated InP

    International Nuclear Information System (INIS)

    Suski, J.; Bourgoin, J.

    1984-01-01

    n and p-InP has been irradiated at 25K with 1MeV electrons and the created defects were studied by deep level transient spectroscopy (DLTS) in the range 25K-400K. In n-InP, four traps are directly observed, with low introduction rates except for one. They anneal in three stages, and four new centers of still lower concentration appear after 70 0 C heat treatment. In p-InP, two dominant traps stable up to approx.= 400K with introduction rates close to the theoretical ones, which might be primary defects are found, while another one is clearly a secondary defect likely associated to Zn dopant. At least two of the low concentration irradiation induced electron traps, created between 25K and 100K are also secondary defects, which implies a mobility of some primary defects down to 100K at least. (author)

  9. Effect of electron beam irradiation on forensic evidence. 2. Analysis of writing inks on porous surfaces.

    Science.gov (United States)

    Ramotowski, Robert S; Regen, Erin M

    2007-05-01

    The effect of electron beam irradiation on a series of different writing inks is described. As the anthrax-tainted letters were discovered in October 2001, the U.S. government began to experiment with the use of the electron beam irradiation process for destroying such biological agents. Plans initially considered a large-scale countrywide use of this technology. However, over time the scope of this plan as well as the radiation dosage were reduced, especially when some adverse consequences to mailed items subjected to this process were observed. Little data existed at the time to characterize what level of damage might be expected to occur with common items sent through the mail. This was especially important to museums and other institutions that routinely ship valuable and historic items through the mail. Although the Smithsonian Institution initiated some studies of the effect of electron beam irradiation on archived materials, little data existed on the effect that this process would have on forensic evidence. Approximately 97 different black, blue, red, green, and yellow writing inks were selected. Writing ink types included ballpoint, gel, plastic/felt tip, and rollerball. All noncontrol samples were subjected to standard mail irradiation conditions used by the U.S. Postal Service at the time this experiment was performed. A video spectral comparator and thin-layer chromatography (TLC) analysis were used to evaluate both the control and the irradiated samples. Some published studies reported changes in the presence/absence of dye bands in the chromatograms of irradiated writing inks. Some of these studies report the formation of additional dye bands on the chromatogram while others report missing dye bands. However, using standard testing guidelines and procedures, none of the 97 irradiated inks tested were found to show any significant optical or chemical differences from the control samples. In addition, random testing of some of the ink samples using a

  10. Reproductive-phase and interphase lethal cell damage after irradiation and treatment with cytostatics

    International Nuclear Information System (INIS)

    Hagemann, G.

    1979-01-01

    After X-ray irradiation of manual cells, two lethal fractions occur due to reproductive and interphase death under low and high radiation doses. The damage kinetics on which this fact is based is compared with hypothetical tumour frequencies and leucemia induction caused in experiments. The reproductive-lethal damage can be manifested by means of colony size spectrometry, with the median colony size class differences (MCD) serving as measure for the damage found. The simultaneous effects of the cytostatics BLEOMYCIN or ICRF 159 and X-rays on reproductive lethal and interphase-lethal damage are measured by means of MCD and survival fraction, and the additive and intensifying effect' is judged with the help of suitably defined terms. This shows that the clinically used ICRF 159 has an additive effect on interphase-lethal and a sub-additive effect on reproductive-lethal cell damage. Thus, favourable results may be expected for the electivity factor in fractionated irradiation and with regard to delayed damage in healthy tissue. (orig.) 891 MG/orig. 892 RDG [de

  11. Surface damage on 6H–SiC by highly-charged Xeq+ ions irradiation

    International Nuclear Information System (INIS)

    Zhang, L.Q.; Zhang, C.H.; Han, L.H.; Xu, C.L.; Li, J.J.; Yang, Y.T.; Song, Y.; Gou, J.; Li, J.Y.; Ma, Y.Z.

    2014-01-01

    Surface damage on 6H–SiC irradiated by highly-charged Xe q+ (q = 18, 26) ions to different fluences in two geometries was studied by means of AFM, Raman scattering spectroscopy and FTIR spectrometry. The FTIR spectra analysis shows that for Xe 26+ ions irradiation at normal incidence, a deep reflection dip appears at about 930 cm −1 . Moreover, the reflectance on top of reststrahlen band decreases as the ion fluence increases, and the reflectance at tilted incidence is larger than that at normal incidence. The Raman scattering spectra reveal that for Xe 26+ ions at normal incidence, surface reconstruction occurs and amorphous stoichiometric SiC and Si–Si and C–C bonds are generated and original Si–C vibrational mode disappears. And the intensity of scattering peaks decreases with increasing dose. The AFM measurement shows that the surface swells after irradiation. With increasing ion fluence, the step height between the irradiated and the unirradiated region increases for Xe 18+ ions irradiation; while for Xe 26+ ions irradiation, the step height first increases and then decreases with increasing ion fluence. Moreover, the step height at normal incidence is higher than that at tilted incidence by the irradiation with Xe 18+ to the same ion fluence. A good agreement between the results from the three methods is found

  12. Electron spin resonance of gamma, electron, neutron and fission fragments irradiated K2SO4

    International Nuclear Information System (INIS)

    Kamali, J.; Walton, G.N.

    1985-01-01

    The electron spin resonance (ESR) of K 2 SO 4 irradiated by γ, electron, neutron and fission fragments has been investigated. The ESR spectra are attributed mainly to the formation of SO 3 - , SO 4 - , SO 2 - , and O 3 - radical ions. The most intense radical ion observed was due to the SO 3 - , and the other radicals were relatively much lower in intensity. Thermal annealing showed a significant decrease in the concentration of radical ions. The concentration of SO 3 - was measured in γ-irradiated K 2 SO 4 and K 2 SO 4 containing fission fragments. In fission fragments irradiated K 2 SO 4 , the G-value observed for SO 3 - radical formation was about eight times higher than that of γ-irradiated K 2 SO 4 . This was attributed to the high LET (Linear Energy Transfer) of the fission fragments. (author)

  13. Damage evaluation of proton irradiated titanium deuteride thin films to be used as neutron production targets

    Science.gov (United States)

    Suarez Anzorena, Manuel; Bertolo, Alma A.; Gagetti, Leonardo; Gaviola, Pedro A.; del Grosso, Mariela F.; Kreiner, Andrés J.

    2018-06-01

    Titanium deuteride thin films have been manufactured under different conditions specified by deuterium gas pressure, substrate temperature and time. The films were characterized by different techniques to evaluate the deuterium content and the homogeneity of such films. Samples with different concentrations of deuterium, including non deuterated samples, were irradiated with a 150 keV proton beam. Both deposits, pristine and irradiated, were characterized by optical profilometry and scanning electron microscopy.

  14. Bulk Cutting of Carbon Nanotubes Using Electron Beam Irradiation

    Science.gov (United States)

    Ziegler, Kirk J. (Inventor); Rauwald, Urs (Inventor); Hauge, Robert H. (Inventor); Schmidt, Howard K. (Inventor); Smalley, Richard E. (Inventor); Kittrell, W. Carter (Inventor); Gu, Zhenning (Inventor)

    2013-01-01

    According to some embodiments, the present invention provides a method for attaining short carbon nanotubes utilizing electron beam irradiation, for example, of a carbon nanotube sample. The sample may be pretreated, for example by oxonation. The pretreatment may introduce defects to the sidewalls of the nanotubes. The method is shown to produces nanotubes with a distribution of lengths, with the majority of lengths shorter than 100 tun. Further, the median length of the nanotubes is between about 20 nm and about 100 nm.

  15. Positron lifetime study of electron-irradiated epoxy resins

    International Nuclear Information System (INIS)

    Suevegh, K.; Vertes, A.; Wojnarovits, L.; Foeldiak, G.; Liszkai, L.; Kajcsos, Zs.

    1990-01-01

    Two bisphenol-A type epoxy resins were irradiated by electron beam and studied afterwards by positron lifetime spectroscopy. An interesting result is that despite of the considerable amount of free-radicals, no inhibition of positronium formation was observed in the two epoxies. Nevertheless, several serious differences were detected between the studied polymers. The results suggest that the radiation-resistant properties of epoxies depend strongly on the amount of the curing agent. (author) 8 refs.; 2 figs

  16. Improving the reverse recovery of power MOSFET integral diodes by electron irradiation

    International Nuclear Information System (INIS)

    Baliga, B.J.; Walden, J.P.

    1983-01-01

    Using 3 MeV electron irradiation at room temperature it was found that the reverse recovery charge in the integral diode could be continuously reduced in a well controlled manner from over 500nC to less than 100nC without any significant increase in the forward voltage drop of the integral diode under typical operating peak currents. The reverse recovery time was also observed to decrease from 3 microseconds to less than 200 nsec when the radiation dose was increased from 0 to 16 Megarads. The damage produced in gate oxide of the MOSFET due to the electron radiation damage was found to cause an undesirable decrease in the gate threshold voltage. This resulted in excessive channel leakage current flow in the MOSFET at zero gate bias. It was found that this channel leakage current was substantially reduced by annealing the devices at 140 0 C without influencing the integral diode reverse recovery speed. Thus, the electron irradiation technique was found to be effective in controlling the integral diode reverse recovery characteristics without any degradation of the power MOSFET characteristics. (author)

  17. Improving the bulk laser-damage resistance of KDP by baking and pulsed-laser irradiation

    International Nuclear Information System (INIS)

    Swain, J.E.; Stokowski, S.E.; Milam, D.; Rainer, F.

    1981-01-01

    Isolated bulk damage centers are produced when KDP crystals are irradiated by 1-ns 1064-nm pulses. We have tested about 100 samples and find the median threshold to be 7 J/cm 2 when the samples are irradiated only once at each test volume (1-on-1 tests). The median threshold increased to 11 J/cm 2 when the test volumes were first subjected to subthreshold laser irradiation (n-on-1 tests). We baked several crystals at temperatures from 110 to 165 0 C and remeasured their thresholds. Baking increased thresholds in some crystals, but did not change thresholds of others. The median threshold of baked crystals ranged from 8 to 10 J/cm 2 depending on the baking temperature. In crystals that had been baked, subthreshold irradiation produced a large change in the bulk damage threshold, and reduced the volume density of damage centers relative to the density observed in unbaked crystals. The data are summarized in the table

  18. Repair of potentially lethal and sublethal radiation damage in x-irradiated ascites tumor cells

    International Nuclear Information System (INIS)

    Tsuboi, Atsushi; Okamoto, Mieko; Tsuchiya, Takehiko.

    1985-01-01

    The ability of cells to repair cellular radiation damage during the growth of TMT-3 ascites tumor and the effect of host reaction on the repair ability were examined by using an in vitro assay of cell clonogenicity after in situ irradiation of tumor cells. In single-dose experiments, the repair of potentially lethal radiation damage (PLD) was observed in stationary phase cells (12-day tumor) of the unirradiated host, but not in exponential phase cells (3-day tumor) of the unirradiated host animals. However, if previously irradiated host animals were used, even the exponentially growing tumor cells showed repair of PLD. In two-dose experiments, the ability to repair sublethal radiation damage (SLD) in exponential phase tumor cells was less than that of stationary phase cells in the unirradiated host. In the pre-irradiated host, the extent of the repair in exponential phase cells was somewhat enhanced. These results suggest that irradiation of host animals might suppress a factor that inhibits repair, resulting in enhancement of the repair capability of tumor cells. (author)

  19. Effect of propolis feeding on rat tissues damaged by X-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Hoon; Seo, Eul Won [Andong National Univ., Andong (Korea, Republic of); Ji, Tae Jeong [Kaya Univ., Goryeong (Korea, Republic of)

    2007-06-15

    Present study aimed to investigate the radioprotective effects of propolis feeding on rat tissues damaged by X-ray irradiation. It was shown that the number of white blood cell in X-ray irradiated group supplemented with propolis increased as much to those of the control group and also the GOT activities among the blood components were decreased after propolis feeding. The mineral contents such as Mg, Fe, Ca, Mn, Cu, Mo, Ni, As in liver were increased as compared with those of the control group but maintained lower level than those of only irradiated groups, implying that the propolis feeding elevated the recovery capability of white blood cell effectively and propolis have a potential resistance to cell damage by X-ray. According to histological observations of the testis, intestine and liver tissues which are irradiated after feeding propolis, the numbers of damaged undifferentiated cells were decreased in testis and the shape of the goblet cells and inner and outer muscular layers in intestine were restored to the original state and the hepatocytes and interlobular veins were shown intact in liver, suggesting that propolis has a potential capacity to restore cell shapes or resist deformation of cell.

  20. Thermoluminescence in KBr:D electron irradiated at room temperature

    International Nuclear Information System (INIS)

    Paredes Campoy, J.C.; Lopez Carranza, E.

    1991-07-01

    The thermoluminescence of KBr:D samples electron irradiated at room temperature after thermal annealing at 673 K for 1 hour have been studied in the temperature range 360-730 K. The experimental TL-curve was discomposed by computer analysis in seven overlapping TL peaks, giving for them the order of the kinetics of thermal stimulation, the activation energy, the frequency factor, the relative values of the electronic concentration in traps at the initial heating temperature and the temperature at the maximum of the peak. (author). 18 refs, 1 fig., 3 tabs

  1. Kinetics of radiation-induced structural alterations in electron-irradiated polymer-based composites

    International Nuclear Information System (INIS)

    Zaikin, Yu.A.; Potanin, A.S.; Koztaeva, U.P.

    2002-01-01

    Complete text of publication follows. In our previous studies measurements of internal friction temperature dependence were used for characterization of thermally activated and radiation-induced structural evolution in different types of polymer-based composites. This paper supplements these measurements with kinetic studies of internal friction (IF) parameters and EPR signals in a glass-cloth epoxy-filled laminate ST-ETF after electron irradiation up to doses of 1-10 MGy. Experiment have shown that the lifetime of free radicals in this composite considerably exceeds the characteristic time of molecular structural rearrangement due to scission and cross-linking after irradiation, as determined from IF measurements. This result is explained by slow proceeding of sterically hindered disproportionation reactions that stabilize the end groups of the macro-chain disrupt during irradiation and finally fix the act of scission. A mathematical model is formulated for description of structural evolution and alterations of IF parameters in polymer-based composites during and after electron irradiation. The description is based on the track model of radiation damage in polymers and phenomenological theory of radiation-induced structural transformations. General description does not give details of radiation-chemical conversion in different structural components of composites but indicates the direction of their structural evolution. In the model considered a composite material was divided into three parts (binder, filler, and a boundary layer). It was supposed that after primary distribution of radiation energy radiation-chemical conversion proceeds independently in each of these regions. It was also suggested that all the radical reactions were of the second order. On the example of glass-cloth laminate ST-ETF it is shown that this model allows to describe alterations in composite structural characteristics during irradiation and in the course of their self-organization after

  2. Compositional redistribution in alloy films under high-voltage electron microscope irradiation

    Science.gov (United States)

    Lam, Nghi Q.; Leaf, O. K.; Minkoff, M.

    1983-10-01

    The problem of nonequilibrium segregation in alloy films under high-voltage electron microscope (HVEM) irradiation at elevated temperatures is re-examined in the present work, taking into account the damage-rate gradients caused by radial variation in the electron flux. Axial and radial compositional redistributions in model solid solutions, representative of concentrated Ni-Cu, Ni-Al and Ni-Si alloys, were calculated as a function of time, temperature, and film thickness, using a kinetic theory of segregation in binary alloys. The numerical results were achieved by means of a new software package (DISPL2) for solving convection-diffusion-kinetics problems with general orthogonal geometries. It was found that HVEM irradiation-induced segregation in thin films consists of two stages. Initially, due to the proximity of the film surfaces as sinks for point defects, the usual axial segregation (to surfaces) occurs at relatively short irradiation times, and rapidly attains quasi-steady state. Then, radial segregation becomes more and more competitive, gradually affecting the kinetics of axial segregation. At a given temperature, the buildup time to steady state is much longer in the present situation than in the simple case of one-dimensional segregation with uniform defect production. Changes in the alloy composition occur in a much larger zone than the irradiated volume. As a result, the average alloy composition within the irradiated region can differ greatly from that of the unirradiated alloy. The present calculations may be useful in the interpretation of the kinetics of certain HVEM irradiation-induced processes in alloys.

  3. The target theory applied to the analysis of irradiation damages in organic detectors

    International Nuclear Information System (INIS)

    Mesquita, Carlos Henrique de

    2005-01-01

    The Target Theory was used to explain the radiation damage in samples containing 1% (g//L) of 2,5-diphenyl-oxazolyl (PPO) diluted in toluene and irradiated with 60 Co (1.8 Gy/s). The survival molecules of irradiated PPO obeys the bi-exponential mathematical model [74.3 x exp(-D/104.3) + 25.7 x exp(-D/800,0)]. It indicates that 74.3% of the molecules decay with D37=104.3 kGy and 25.7% decay with D37=800 kGy. From the Target Theory it was inferred the energies involved in the irradiation damages which were 0.239 ± 0.031 eV (G=418.4 ± 54.1. damages/100 eV) and 1.83 ± 0.30 eV (54.5 ± 8.9 damages/100 eV). The diameter of PPO molecule estimated from the Target Theory is in the interval of 45.5 to 64.9 angstrom. (author)

  4. A COMPARISON OF DNA DAMAGE PROBES IN TWO HMEC LINES WITH X-IRRADIATION

    Energy Technology Data Exchange (ETDEWEB)

    Wisnewski, C.L.; Bjornstad, K.A.; Rosen, C.J.; Chang, P.Y.; Blakely, E.A.

    2007-01-01

    In this study, we investigated γH2AXser139 and 53BP1ser25, DNA damage pathway markers, to observe responses to radiation insult. Two Human Mammary Epithelial Cell (HMEC) lines were utilized to research the role of immortalization in DNA damage marker expression, HMEC HMT-3522 (S1) with an infi nite lifespan, and a subtype of HMEC 184 (184V) with a fi nite lifespan. Cells were irradiated with 50cGy X-rays, fi xed with 4% paraformaldehyde after 1 hour repair at 37°C, and processed through immunofl uorescence. Cells were visualized with a fl uorescent microscope and images were digitally captured using Image-Pro Plus software. The 184V irradiated cells exhibited a more positive punctate response within the nucleus for both DNA damage markers compared to the S1 irradiated cells. The dose and time course will be expanded in future studies to augment the preliminary data from this research. It is important to understand whether the process of transformation to immortalization compromises the DNA damage sensor and repair process proteins of HMECs in order to understand what is “normal” and to evaluate the usefulness of cell lines as experimental models.

  5. A comparison of DNA damage probes in two HMEC lines withX-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wisnewski, Christy L.; Bjornstad, Kathleen A.; Rosen, ChristoperJ.; Chang, Polly Y.; Blakely, Eleanor A.

    2007-01-19

    In this study, we investigated {gamma}H2AX{sup ser139} and 53BP1{sup ser25}, DNA damage pathway markers, to observe responses to radiation insult. Two Human Mammary Epithelial Cell (HMEC) lines were utilized to research the role of immortalization in DNA damage marker expression, HMEC HMT-3522 (S1) with an infinite lifespan, and a subtype of HMEC 184 (184V) with a finite lifespan. Cells were irradiated with 50 cGy X-rays, fixed with 4% paraformaldehyde after 1 hour repair at 37 C, and processed through immunofluorescence. Cells were visualized with a fluorescent microscope and images were digitally captured using Image-Pro Plus software. The 184V irradiated cells exhibited a more positive punctate response within the nucleus for both DNA damage markers compared to the S1 irradiated cells. We will expand the dose and time course in future studies to augment the preliminary data from this research. It is important to understand whether the process of transformation to immortalization compromises the DNA damage sensor and repair process proteins of HMECs in order to understand what is 'normal' and to evaluate the usefulness of cell lines as experimental models.

  6. Dosimetry study for electron beam irradiation in radiation processing

    International Nuclear Information System (INIS)

    Sunaga, Hiromi; Haruyama, Yasuyuki; Takizawa, Haruki; Kojima, Takuji; Yotsumoto, Keiichi

    1995-01-01

    For certain critical applications such as medical device sterilization and food irradiation, accurate calibration of electron energy and absorbed dose is required to assure the quality of irradiated products. To meet this requirement, TRCRE, JAERI has carried out research and development on high dose radiation dosimetry for electron beams in the energy range used in radiation processing (0.15 - 3.0 MeV). JAERI has developed a simultaneous electron beam energy and dosimeter calibration system that consist of a total absorption calorimeter, an electron current density meter, and a stacked thin-film dosimeter set. For low energy electrons, where it is important to measure the depth-dose profile in materials with high depth resolution, we studied the feasibility of a method using Gafchromic film dosimeters. This film, which has an 8-μm thick sensitive layer, is combined with a stepped array of absorber films of the same thickness to produce a high-resolution depth-dose profile on the Gafchromic film. The depth-dose profile obtained in this manner has about five times greater resolution than conventional radiochromic film dosimetry. (author)

  7. Space-charge-limited currents in electron-irradiated dielectrics

    International Nuclear Information System (INIS)

    Nunes de Oliveira, L.; Gross, B.

    1975-01-01

    This paper develops the theory of steady-state currents generated in a dielectric placed between positively or negatively biased electrodes and irradiated with a partially penetrating electron beam. The dielectric is divided into an irradiated region (IR), which extends from the electrode of incidence to the extrapolated range of the beam, and a nonirradiated region (NIR). In the IR the primary beam generates an electron-hole plasma. Its end plane acts as a virtual electrode embedded in the dielectric. Currents are space-charge limited in the NIR and Ohmic in the IR which is characterized by a uniform radiation-induced conductivity. Depending on the polarity of the electrode bias, electrons or holes are drawn from the IR into the NIR. The theory correctly predicts an apparent threshold effect for the inset of steady-state currents: the current amplitudes remain small as long as the electron range is smaller than half the sample thickness, and increase strongly only afterwards. Calculated current curves for different beam energies are in satisfactory agreement with experimental results. The role of the electron beam as a virtual electrode is discussed

  8. Disinfection of wastewaters: high-energy electron vs gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Farooq, S [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Dept. of Civil Engineering; Kurucz, C N; Waite, T D [Miami Univ., Coral Gables, FL (United States); Cooper, W J [Florida International Univ., Miami, FL (United States). Drinking Water Research Center

    1993-07-01

    A study was undertaken to examine the sensitivity of a wastewater population of coliphage, total coliforms and total flora present in raw sewage and secondary effluent after irradiating with similar doses delivered by a high-energy electron beam and [gamma]-radiation. The electron beam study was conducted on a large scale at the Virginia Key Wastewater Treatment Plant, Miami, Florida. The facility is equipped with a 1.5 MeV, 50 mA electron accelerator, with a wastewater flow rate of 8ls[sup -1]. Concurrent [gamma]-radiation studies were conducted at laboratory scale using a 5000 Ci, [sup 60]Co [gamma]-source. Three logs reduction of all three test organisms were observed at an electron beam dose of 500 krads, while at least four logs reduction were observed at the same dose utilizing the [gamma]'source. (Author).

  9. Inactivation of catalase monolayers by irradiation with 100 keV electrons

    International Nuclear Information System (INIS)

    Hahn, M.; Seredynski, J.; Baumeister, W.

    1976-01-01

    A catalase monolayer adsorbed on a layer of arachidic acid deposited on a solid support was irradiated with 100 keV electrons simulating the conditions of electron microscopic imaging. Effective doses were calculated taking into account the angular and energy distribution of backscattered electrons. Enzymatic inactivation was chosen as the criterion for damage and was monitored by a rapid and quantifiable but nevertheless sensitive assay. Dose-response curves revealed that inactivation is a one-hit--multiple-target phenomenon, which is consistent with biochemical evidence for a cooperative function of subunits. The experimentally determined target size coincides fairly well with both calculated cross sections for inelastic interactions based on the atomic composition of catalase and with calculated cross sections for ionizing events based on the chemical bonds involved. This legitimates both types of calculations even for complex biomolecules

  10. Implementing displacement damage calculations for electrons and gamma rays in the Particle and Heavy-Ion Transport code System

    Science.gov (United States)

    Iwamoto, Yosuke

    2018-03-01

    In this study, the Monte Carlo displacement damage calculation method in the Particle and Heavy-Ion Transport code System (PHITS) was improved to calculate displacements per atom (DPA) values due to irradiation by electrons (or positrons) and gamma rays. For the damage due to electrons and gamma rays, PHITS simulates electromagnetic cascades using the Electron Gamma Shower version 5 (EGS5) algorithm and calculates DPA values using the recoil energies and the McKinley-Feshbach cross section. A comparison of DPA values calculated by PHITS and the Monte Carlo assisted Classical Method (MCCM) reveals that they were in good agreement for gamma-ray irradiations of silicon and iron at energies that were less than 10 MeV. Above 10 MeV, PHITS can calculate DPA values not only for electrons but also for charged particles produced by photonuclear reactions. In DPA depth distributions under electron and gamma-ray irradiations, build-up effects can be observed near the target's surface. For irradiation of 90-cm-thick carbon by protons with energies of more than 30 GeV, the ratio of the secondary electron DPA values to the total DPA values is more than 10% and increases with an increase in incident energy. In summary, PHITS can calculate DPA values for all particles and materials over a wide energy range between 1 keV and 1 TeV for electrons, gamma rays, and charged particles and between 10-5 eV and 1 TeV for neutrons.

  11. Radiation Damage in Silicon Detectors Caused by Hadronic and Electromagnetic Irradiation

    CERN Document Server

    Fretwurst, E.; Stahl, J.; Pintilie, I.

    2002-01-01

    The report contains various aspects of radiation damage in silicon detectors subjected to high intensity hadron and electromagnetic irradiation. It focuses on improvements for the foreseen LHC applications, employing oxygenation of silicon wafers during detector processing (result from CERN-RD48). An updated survey on hadron induced damage is given in the first article. Several improvements are outlined especially with respect to antiannealing problems associated with detector storage during LHC maintenance periods. Open questions are outlined in the final section, among which are a full understanding of differences found between proton and neutron induced damage, process related effects changing the radiation tolerance in addition to the oxygen content and the lack of understanding the changed detector properties on the basis of damage induced point and cluster defects. In addition to float zone silicon, so far entirely used for detector fabrication,Czochralski silicon was also studied and first promising re...

  12. Recovery from sublethal damage during fractionated irradiation of human FaDu SCC

    International Nuclear Information System (INIS)

    Petersen, Cordula; Zips, Daniel; Krause, Mechthild; Voelkel, Wolfram; Thames, Howard D.; Baumann, Michael

    2005-01-01

    Background and purpose: The present study addresses whether recovery of sublethal damage in tumours may change during fractionated irradiation in FaDu human squamous cell carcinoma and whether such an effect might contribute to the pronounced time factor of fractionated irradiation previously found in this tumour. Patients and methods: FaDu tumours were transplanted s.c. into the right hind leg of NMRI nu/nu mice. Single doses or 2, 4, and 8 equal fractions in 3.5 days were applied in previously unirradiated tumours and after priming with 18 fractions of 3 Gy in 18 or 36 days. All irradiations were given under clamp hypoxic conditions. Experimental endpoints were tumour control dose 50% (TCD 50 ) and α/β values without and after priming. Results: Without priming TCD 50 increased with increasing number of fractions from 38.8 Gy (95% CI 35;45) after single dose irradiation to 54.0 Gy (42;57) after 8 fractions. No increase in TCD 50 when given in 1, 2, 4, or 8 fractions in 3.5 days was found after priming with 18 3-Gy fractions in 18 and 36 days. After priming with 18 fractions in 18 days TCD 50 remained constant at 25 Gy and after priming with 18 fractions in 36 days at 42 Gy. The α/β ratio without priming was 68 Gy (42;127). After fractionated irradiation with 18 3-Gy fractions in 18 and 36 days the α/β ratio increased to 317 Gy (38;∞) and to infinite, respectively. Conclusions: Our results indicate that clonogenic cells in FaDu tumours lose entirely their capacity to recover from sublethal radiation damage during fractionated irradiation. Therefore, an increased repair capacity as an explanation for the pronounced time factor of fractionated irradiation in this tumour can be ruled out

  13. Gamma irradiation of the fetus damages the developing hemopoietic microenvironment rather than the hemopoietic progenitor cells

    International Nuclear Information System (INIS)

    Yang, F.T.; Lord, B.I.; Hendry, J.H.

    1995-01-01

    Hemopoiesis is the product of two components: the hemopoietic tissue and the regulatory stromal microenvironment in which it resides. Plutonium-239, incorporated during fetal development in mice, is known to cause deficient hemopoiesis. A predetermined equivalent γ-ray dose has now been used in combination with cross-transplantation experiments to separate these two components and define where the damage arises. It was confirmed that 1.8 Gy γ irradiation at midterm gestation caused a 40% reduction in the hemopoietic stem (spleen colony-forming) cell population of their offspring which persisted to at least 24 weeks of age. Spleen colony formation after sublethal doses of γ rays reflected this reduced complement of endogenous stem cells. The regulatory hemopoietic microenvironment, measured as fibroblastoid colony-forming cells, was similarly depleted. Normal growth of the CFU-S population after transplantation into standard recipients showed that the quality of the stem cell population in the offspring of irradiated mothers was not affected. By contrast, when used as recipients of a bone marrow transplant from either normal or irradiated offspring, the offspring of irradiated mothers were unable to support normal growth: there was a twofold difference in the number of CFU-S per femur for at least 100 days after transplantation. There were 70% fewer CFU-F in the femur 1 month after bone marrow transplantation when the offspring of irradiated mothers were used as transplant recipients compared to when normal offspring were used. This not only confirmed their reduced capacity to host normal stem cells but also indicated that CFU-F in the transplant were unable to compensate for the poor microenvironment in the irradiated offspring hosts. It is concluded that irradiation at midterm gestation damages the developing regulatory microenvironment but not the hemopoietic stem cell population that it hosts. 12 refs., 1 fig., 4 tabs

  14. Effects of piracetam supplementation on cochlear damage occuring in guinea pigs exposed to irradiation

    International Nuclear Information System (INIS)

    Altas, E.; Ertekin, M.V.; Kuduban, O.; Gundogdu, C.; Demirci, E.; Sutbeyaz, Y.

    2006-01-01

    In this study we aimed to determine the role of piracetam (PIR) in preventing radiation induced cochlear damage after total-cranium irradiation (radiotherapy; RT). Male albino guinea pigs used in the study were randomly divided into three groups. Group 1 (Control group) (n=11) received neither PIR nor irradiation, but received saline solution intraperitoneally (i.p.) and received sham irradiation. Group 2 (RT group) (n=32) was exposed to total cranium irradiation of 33 Gy in 5 fractions of 6.6 Gy/d for five successive days, with a calculated (α/β=3.5) biological effective dose of fractionated irradiation equal to 60 Gy conventional fractionation, then received saline solution for five successive days i.p. Group 3 (PIR+RT group) (n=33) received total cranium irradiation, plus 350 mg/kg per day PIR for five successive days i.p. After the last dose of RT, the guinea pigs were all sacrificed at the 4th, 24th and 96th hours, respectively. Their cochleas were enucleated for histopathologic examination. It was observed that total cranium irradiation (RT group) promoted degeneration in stria vascularis (SV), spiral ganglion cells (SG), outer hair cells (OHC) and inner hair cell (IHC) of cochleas at these times (p 0.05) and IHC at 4th, 24th hours (p>0.05), there was a significant difference on radiation-induced cochlear degeneration in SV and OHC at 24th and 96th hours (p<0.05), IHC at 96th hour (p<0.05) and SG at 4th, 24th and 96th hours (p<0.05). There was no any cochlear degeneration in the control group. Piracetam might reduce radiation-induced cochlear damage in the guinea pig. These results are pioneer to studies that will be performed with PIR for radiation toxicity protection. (author)

  15. The effect of simultaneous electron and Kr+ irradiation on amorphization of CuTi

    International Nuclear Information System (INIS)

    Koike, J.; Okamoto, P.R.; Rehn, L.E.; Meshii, M.

    1989-01-01

    CuTi was irradiated with 1-MeV electrons and Kr + ions simultaneously at temperatures from 10 to 423 K. Retardation of Kr + -induced amorphization was observed with simultaneous electron irradiation at 295 and 423 K. The retardation effect increased with increasing irradiation temperature and relative electron-to-Kr dose rate. In contrast, simultaneous irradiation below 100 K showed an additive effect of electron- and Kr + -induced amorphization. The results can be explained by the mobility point defects introduced by electron irradiation interacting with Kr + -induced displacement cascades. 6 refs., 6 figs

  16. Assessment of DNA damage induced by terrestrial UV irradiation of dried bloodstains: forensic implications.

    Science.gov (United States)

    Hall, Ashley; Sims, Lynn M; Ballantyne, Jack

    2014-01-01

    Few publications have detailed the nature of DNA damage in contemporary (i.e. non-ancient) dried biological stains. The chief concern, from a forensic standpoint, is that the damage can inhibit polymerase-mediated primer extension, ultimately resulting in DNA typing failure. In the work described here, we analyzed the effects of UVA and UVB irradiation on cell-free solubilized DNA, cell-free dehydrated DNA and dehydrated cellular DNA (from bloodstains). After UV exposure ranging from 25 J cm(-2) to 1236 J cm(-2), we assayed for the presence of bipyrimidine photoproducts (BPPPs), oxidative lesions and strand breaks, correlating the damage with the inhibition of STR profiling. Subsequent to irradiation with either UVA and UVB, the incidence of BPPPs, oxidative products and strand breaks were observed in decreasing quantities as follows: cell-free solubilized DNA>cell-free dehydrated DNA>bloodstain DNA. UVA irradiation did not result in even the partial loss of a STR profile in any sample tested. Somewhat different results were observed after genetic analysis of UVB exposed samples, in that the ability to produce a complete STR profile was affected earliest in bloodstain DNA, next in cell-free solubilized DNA and not at all in cell-free dehydrated DNA. Therefore, it is likely that other types of damage contributed to allele-drop-out in these samples but remained undetected by our assays, whereby the endonucleases did not react with the lesions or the presence of the lesions was masked by strand breaks. Under the conditions of the study, strand breaks appeared to be the predominant types of damage that ultimately resulted in DNA typing failure from physiological stains, although some evidence suggested oxidative damage may have played a role as well. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  17. Vulcanization of rubber mixtures by simultaneous electron beam and microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Martin, D. E-mail: martin@ifin.nipne.ro; Ighigeanu, D.; Mateescu, E.; Craciun, G.; Ighigeanu, A

    2002-08-01

    The comparative results obtained by applying separate electron beam (EB) irradiation and simultaneous EB and microwave (MW) irradiation to vulcanization of rubber mixtures based on natural rubber and polybutadiene rubber with carbon black are presented. In the absence of MW, EB irradiation doses of 200-250 kGy are required in order to obtain a higher vulcanization degree. The irradiation doses as well as irradiation times were markedly diminished, from 2 to 6 times, by simultaneous EB and MW irradiation.

  18. Methodology for determining void swelling at very high damage under ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Getto, E., E-mail: embecket@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Sun, K. [Department of Materials Science Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Taller, S.; Monterrosa, A.M.; Jiao, Z. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Was, G.S. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Department of Materials Science Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)

    2016-08-15

    At very high damage levels in ion irradiated samples, the decrease in effective density of the irradiated material due to void swelling can lead to errors in quantifying swelling. HT9 was pre-implanted with 10 appm He and subjected to a raster-scanned beam with a damage rate of ∼1 × 10{sup −3} dpa/s at 460{sup o}C. Voids were characterized from 0 to 1300 nm. Fixed damage rate and fixed depth methods were developed to account for damage-dependent porosity increase and resulting dependence on depth. The fixed depth method was more appropriate as it limits undue effects from the injected interstitial while maintaining a usable void distribution. By keeping the depth fixed and accounting for the change in damage rate due to reduced density, the steady state swelling rate was 10% higher than calculation of swelling from raw data. This method is easily translatable to other materials, ion types and energies and limits the impact of the injected interstitial.

  19. Validity of reciprocity rule on mouse skin thermal damage due to CO2 laser irradiation

    Science.gov (United States)

    Parvin, P.; Dehghanpour, H. R.; Moghadam, M. S.; Daneshafrooz, V.

    2013-07-01

    CO2 laser (10.6 μm) is a well-known infrared coherent light source as a tool in surgery. At this wavelength there is a high absorbance coefficient (860 cm-1), because of vibration mode resonance of H2O molecules. Therefore, the majority of the irradiation energy is absorbed in the tissue and the temperature of the tissue rises as a function of power density and laser exposure duration. In this work, the tissue damage caused by CO2 laser (1-10 W, ˜40-400 W cm-2, 0.1-6 s) was measured using 30 mouse skin samples. Skin damage assessment was based on measurements of the depth of cut, mean diameter of the crater and the carbonized layer. The results show that tissue damage as assessed above parameters increased with laser fluence and saturated at 1000 J cm-2. Moreover, the damage effect due to high power density at short duration was not equivalent to that with low power density at longer irradiation time even though the energy delivered was identical. These results indicate the lack of validity of reciprocity (Bunsen-Roscoe) rule for the thermal damage.

  20. Lifetime of Macroradicals in UHMWPE Irradiated with Electron Beam

    International Nuclear Information System (INIS)

    Costa, L.

    2006-01-01

    Interaction of high energy radiation with UHMWPE leads to the scission of C-C and C-H bonds both in the amorphous and in the criystalline phase, giving H radicals, macroradicals and trans vinylene double bonds. If oxygen is present, alkyl macroradicals react immediately with it and the oxidation chain process begins. In this case the main products are hydroperoxides. In our laboratory ultra high molecular weight polyethylene (medical grade GUR 1050) has been irradiated with electron beam in vacuum and in presence of oxygen at room temperature. Electron beam irradiation has been considered in order to neglect irradiation time, that is shorter (maximum 2 minutes) than gamma irradiation time and negligible compared to the following observation time. UHMWPE irradiated has been examined with two different techniques, FTIR and EPR spectroscopy. Micro FTIR Spectroscopy has been carried out on UHMWPE to evaluate hydroperoxide concentration in samples irradiated in presence of oxygen. Hydroperoxides and their distribution inside samples can be observed very well with FTIR microscopy after a derivatization process (with NO). The obtained hydroperoxide profile decreases when distance from the outer surface increases till it achieves a plateau. The first decrease can be attributed to macroradicals reaction with oxygen, that can diffuse only in the amorphous phase. Value obtained in the centre of block is correlated only with oxygen dissolved in UHMWPE before irradiation. If radicals live for some hours, oxygen can diffuse into UHMWPE during the macroradicals lifetime and the hydroperoxides profile is a curve similar to that obtained. Comparing the oxygen diffusion curve, calculated in the function of Fick's law, with the hydroperoxide profile, we have obtained a good agreement when oxygen diffusion is calculated over two hours. This means that the macroradicals must survive at least for two hours in the amorphous phase. EPR Spectroscopy was undertaken to explore the nature of

  1. Radiation doses inside industrial irradiation installation with linear electron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Alexandre R., E-mail: alexandre.lima@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil); Pelegrineli, Samuel Q.; Alo, Gabriel F., E-mail: samuelfisica@yahoo.com.br, E-mail: gabriel.alo@aceletron.com.br [Aceletron Irradiacao Industrial, Aceletrica Comercio e Representacoes Ltda, Rio de Janeiro, RJ (Brazil); Silva, Francisco C.A. Da, E-mail: dasilva@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    Aceletron Industrial Irradiation Company is the unique installation in South America to provide industrial irradiation service using two linear electron accelerators of 18 kW and 10 MeV energy. The electron beam technology allows using electrons to irradiate many goods and materials, such as hospital and medical equipment, cosmetics, herbal products, polymers, peat, gemstones and food. Aceletron Company uses a concrete bunker with 3.66 m of thickness to provide the necessary occupational and environmental radiation protection of X-rays produced. The bunker is divided in main four areas: irradiation room, maze, tower and pit. Inside the irradiation room the x-rays radiation rates are measured in two ways: direct beam and 90 deg C. The rates produced in the conveyor system using 10 MeV energy are 500 Gy/min/mA and 15 Gy/min/mA, respectively. For a 1.8 mA current, the rates produced are 900 Gy/min and 27 Gy/min, respectively. Outside the bunker the radiation rate is at background level, but in the tower door and modulation room the radiation rate is 10 μSv/h. In 2014, during a routine operation, an effective dose of 30.90 mSv was recorded in a monthly individual dosimeter. After the investigation, it was concluded that the dose was only in the dosimeter because it felt inside the irradiation room. As Aceletron Company follows the principles of safety culture, it was decided to perform the radiation isodose curves, inside the four areas of the installation, to know exactly the hotspots positions, exposure times and radiation doses. Five hotspots were chosen taking into account worker's routes and possible operational places. The first experiment was done using a package with three TLD and OSLD dosimeters to obtain better statistical results. The first results for the five hotspots near the accelerator machine showed that the radiation dose rates were between 26 Gy/h and 31 Gy/h. The final measurements were performed using a package with one TLD and one OSLD

  2. Radiation doses inside industrial irradiation installation with linear electron accelerator

    International Nuclear Information System (INIS)

    Lima, Alexandre R.; Pelegrineli, Samuel Q.; Alo, Gabriel F.; Silva, Francisco C.A. Da

    2015-01-01

    Aceletron Industrial Irradiation Company is the unique installation in South America to provide industrial irradiation service using two linear electron accelerators of 18 kW and 10 MeV energy. The electron beam technology allows using electrons to irradiate many goods and materials, such as hospital and medical equipment, cosmetics, herbal products, polymers, peat, gemstones and food. Aceletron Company uses a concrete bunker with 3.66 m of thickness to provide the necessary occupational and environmental radiation protection of X-rays produced. The bunker is divided in main four areas: irradiation room, maze, tower and pit. Inside the irradiation room the x-rays radiation rates are measured in two ways: direct beam and 90 deg C. The rates produced in the conveyor system using 10 MeV energy are 500 Gy/min/mA and 15 Gy/min/mA, respectively. For a 1.8 mA current, the rates produced are 900 Gy/min and 27 Gy/min, respectively. Outside the bunker the radiation rate is at background level, but in the tower door and modulation room the radiation rate is 10 μSv/h. In 2014, during a routine operation, an effective dose of 30.90 mSv was recorded in a monthly individual dosimeter. After the investigation, it was concluded that the dose was only in the dosimeter because it felt inside the irradiation room. As Aceletron Company follows the principles of safety culture, it was decided to perform the radiation isodose curves, inside the four areas of the installation, to know exactly the hotspots positions, exposure times and radiation doses. Five hotspots were chosen taking into account worker's routes and possible operational places. The first experiment was done using a package with three TLD and OSLD dosimeters to obtain better statistical results. The first results for the five hotspots near the accelerator machine showed that the radiation dose rates were between 26 Gy/h and 31 Gy/h. The final measurements were performed using a package with one TLD and one OSLD

  3. Application of electron paramagnetic resonance to identify irradiated soybean

    International Nuclear Information System (INIS)

    Bhaskar, S.; Behere, Arun; Sharma, Arun

    2006-01-01

    Full text: Electron paramagnetic resonance spectroscopy was applied to study free radicals in soy bean seed after gamma irradiation and to establish the potential of these radiation induced free radicals as the indicator of the radiation treatment. The radiation doses administered to the samples were 1 to 30 kGy. A stable doublet signal was detected at g = 2.0279 with hyperfine coupling constant of 2.8 mT, produced only by radiolysis. This signal can be used to identify irradiated soy bean seed samples. With the increase of the radiation dose the central line intensity and the intensities of the satellite lines showed almost a linear rise having linear correlation factors of 0.99724 and 0.99996, respectively. Thermal treatment at 373 deg K in air was studied. No line specific to thermolysis was observed. The spectrometer was operated with power 0.253 mW, microwave frequency 9.74 GHz, modulation frequency 100 kHz and scan range 10 mT. To study the stability of the signal, EPR spectra were obtained from the irradiated skin part of soy bean seeds samples following 1 and 90 days of storage after radiation treatment. The two satellite lines of g left = 2.0279 and g right 1.99529 were detected in all samples. This suggests that the signal is associated with a stable radical and therefore, the detection of a particular free radical as a marker of irradiation is proposed

  4. Irradiation Effects of Electron Beam on Optical Fibers

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Kyu; Cho, Gyu Seong [KAIST, Daejeon (Korea, Republic of); Choi, Hong Gu; Oh, Kyung Hwan [Yonsei University, Seoul (Korea, Republic of); Cho, Ho Jin [Nucron Co. Ltd., Seoul (Korea, Republic of)

    2009-10-15

    The surveillance or monitoring systems used in space station, nuclear power plant and nuclear waste repository, are often equipped with optical fibers to remotely locating expensive camera systems so as to protect them from direct irradiation. Especially in nuclear power plant and nuclear waste repository, irradiation by gamma-ray and beta-ray are most concerned. The effective life-time of such surveillance system may depend on the soundness of the optical fiber because it is the component to be exposed the high intensity of radiation field by purpose. Though the degradation of mechanical properties such as hardness and elasticity may occur but the degradation of the optical property such as spectral transmittance is the most possible cause of the effective life-time limitation. Generally 30 % reduction of light signal transmittance is considered as the life-time threshold point of such optical systems. In this paper, we studied irradiation effects on spectral transparency of various commonly-used optical fibers with high energy electron beam to conveniently simulate the both gamma-ray and beta-ray irradiation situation.

  5. Electron beam irradiation effects on xanthan gum. Rheological aspects

    International Nuclear Information System (INIS)

    Vieira, F.F.; Del Mastro, N.L.

    2001-01-01

    The paper describes the application of electron beam irradiation to xanthum gum as used as ingredient by the food or cosmetics industry in order to establish their radiosensitivity. The edible powder of xanthum gum samples were irradiated in 1mm thick layers of Petri dishes covered by a transparent PVC of films using an EB accelerator Dynamitron (Radiation Dynamics Inc.) model JOB 188, dose rate 11.17 kGy/s, 0.637 MeV, 1.78 mA, 5 kGy per passage, 3.36 m min -1 with doses of 5, 10, 20 and 50kGy. One % aqueous solutions from irradiated and non-irradiated xanthum gum were prepared and the radiation effects were measured following viscosity changes at 25 deg. C using a Brookfield viscometer; model DVIII, spindel L, with Rheocalc software. Viscosity measurements were performed according to our previous experience and the results are the mean of at least 3 experiments

  6. An experimental investigation of wastewater treatment using electron beam irradiation

    Science.gov (United States)

    Emami-Meibodi, M.; Parsaeian, M. R.; Amraei, R.; Banaei, M.; Anvari, F.; Tahami, S. M. R.; Vakhshoor, B.; Mehdizadeh, A.; Fallah Nejad, N.; Shirmardi, S. P.; Mostafavi, S. J.; Mousavi, S. M. J.

    2016-08-01

    Electron beam (EB) is used for disinfection and treatment of different types of sewage and industrial wastewater. However, high capital investment required and the abundant energy consumed by this process raise doubts about its cost-effectiveness. In this paper, different wastewaters, including two textile sewages and one municipal wastewater are experimentally studied under different irradiation strategies (i.e. batch, 60 l/min and 1000 m3/day) in order to establish the reliability and the optimum conditions for the treatment process. According to the results, EB improves the efficiency of traditional wastewater treatment methods, but, for textile samples, coagulation before EB irradiation is recommended. The cost estimation of EB treatment compared to conventional methods shows that EB has been more expensive than chlorination and less expensive than activated sludge. Therefore, EB irradiation is advisable if and only if conventional methods of textile wastewater treatment are insufficient or chlorination of municipal wastewater is not allowed for health reasons. Nevertheless, among the advanced oxidation processes (AOP), EB irradiation process may be the most suitable one in industrial scale operations.

  7. Optical properties of electron-irradiated gallium phosphide

    International Nuclear Information System (INIS)

    Brailovskii, E.Yu.; Grigoryan, N.E.; Eritsyan, G.N.

    1980-01-01

    Results of optical absorption and photoconductivity measurements in the 0.1 to 2.4 eV range of GaP crystals irradiated with 7.5 and 50 MeV electrons are presented. The absorption of irradiated crystals near the edge can be represented by two exponential regions. In the free carrier absorption region one can observe as a result of irradiation a decrease of the power index p in the dependence α proportional to lambdap. Photoconductivity with long-time relaxation takes place in the spectral interval where the additional absorption is observed. The quenching of residual conductivity can be observed at hν=1.0eV. Variations in absorption and photoconductivity are attributed to the 'tails' of density states near the zone edges arising at introduction of both point defects and disordered regions. At hν=2.1eV one can observe a resonance band which is attributed to intra-centre transitions on point defects. A recovery of the optical properties of GaP at annealing is studied. In heavily irradiated GaP crystals point defects can form gatherings which display themselves as disordered regions. (author)

  8. Irradiation damage in gamma lithium aluminate - LiAlO2

    International Nuclear Information System (INIS)

    Auvray-Gely, M.H.

    1989-01-01

    Single crystals of gamma lithium aluminate (of tetragonal structure) are irradiated) with various projectiles (electrons, He ions, protons, X and gamma photons) and we used (i) electronic paramagnetic resonance (EPR) and optical absorption to detect the defects produced, and (ii) transmission electron microscopy (TEM). The lithium aluminate single crystals irradiated with electrons or ions contain five different paramagnetic defects. Each of them has several anisotropic configurations whose EPR signals (i) have a Lande factor close to 2, (ii) exhibit a resolved hyperfine structure and (iii) are identical only when the static magnetic field is along /001/. In addition, four optical absorption bands appear in the range 1-6 eV in the same irradiation conditions. But only three among the five paramagnetic defects and one of the optical bands appear in X-and gamma-ray irradiated samples. Using these observations, we discuss the nature of the detected defects and we conclude about the type of their production mechanism. Particularly, we assign a six-line EPR signal and an optical band in the ultraviolet range to the F + -centre. We compare this hypothesis to a defect model based on the computation of approximate electronic wave functions using the variational method. Our TEM study shows that when gamma-LiAlO 2 single crystals are irradiated with 1 MeV electrons (fluence: 10 20 electrons/sqcm), tridimensional defects (of mean dimension 100 nm) appear. At lower energies, the defect production is hidden by a thermal effect that is sufficient to induce the evaporation of lithium oxyde and the formation of LiAl 5 0 8 [fr

  9. Histochemical evidence for the relationship between peel damage and the accumulation of phenolic compounds in gamma-irradiated citrus fruit

    International Nuclear Information System (INIS)

    Riov, J.

    1975-01-01

    The first symptoms of radiation damage to citrus fruit were noted 24 to 48 hr after irradiation with 240 krad of gamma rays. At about the same time, radiation-damaged cells were observed in peel cross sections in the flavedo, the outer colored peel layers. The damaged cells were deformed and their protoplasts stained much darker with haematoxylin-safranin than protoplasts of intact cells. The cytoplasm in damaged cells either thickened at one side of the cell, sometimes filling up most of the cell space, or contracted into a small mass. Using several histochemical reagents, a considerable accumulation of phenolic compounds was found to occur in the damaged cells shortly after irradiation. No accumulation of phenolic compounds was observed in intact cells of irradiated fruit. It is suggested that the phenolic compounds which accumulate in flavedo cells following irradiation cause cell death and consequent peel necrosis (pitting). (author)

  10. DNA damage response signaling in lung adenocarcinoma A549 cells following gamma and carbon beam irradiation.

    Science.gov (United States)

    Ghosh, Somnath; Narang, Himanshi; Sarma, Asitikantha; Krishna, Malini

    2011-11-01

    Carbon beams (5.16MeV/u, LET=290keV/μm) are high linear energy transfer (LET) radiation characterized by higher relative biological effectiveness than low LET radiation. The aim of the current study was to determine the signaling differences between γ-rays and carbon ion-irradiation. A549 cells were irradiated with 1Gy carbon or γ-rays. Carbon beam was found to be three times more cytotoxic than γ-rays despite the fact that the numbers of γ-H2AX foci were same. Percentage of cells showing ATM/ATR foci were more with γ-rays however number of foci per cell were more in case of carbon irradiation. Large BRCA1 foci were found in all carbon irradiated cells unlike γ-rays irradiated cells and prosurvival ERK pathway was activated after γ-rays irradiation but not carbon. The noteworthy finding of this study is the early phase apoptosis induction by carbon ions. In the present study in A549 lung adenocarcinoma, authors conclude that despite activation of same repair molecules such as ATM and BRCA1, differences in low and high LET damage responses might be due to their distinct macromolecular complexes rather than their individual activation and the activation of cytoplasmic pathways such as ERK, whether it applies to all the cell lines need to be further explored. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. ALK1 heterozygosity delays development of late normal tissue damage in the irradiated mouse kidney

    International Nuclear Information System (INIS)

    Scharpfenecker, Marion; Floot, Ben; Korlaar, Regina; Russell, Nicola S.; Stewart, Fiona A.

    2011-01-01

    Background and Purpose: Activin receptor-like kinase 1 (ALK1) is a transforming growth factor β (TGF-β) receptor, which is mainly expressed in endothelial cells regulating proliferation and migration in vitro and angiogenesis in vivo. Endothelial cells also express the co-receptor endoglin, which modulates ALK1 effects on endothelial cells. Our previous studies showed that mice with reduced endoglin levels develop less irradiation-induced vascular damage and fibrosis, caused by an impaired inflammatory response. This study was aimed at investigating the role of ALK1 in late radiation toxicity. Material and Methods: Kidneys of ALK +/+ and ALK1 +/- mice were irradiated with 14 Gy. Mice were sacrificed at 10, 20, and 30 weeks after irradiation and gene expression and protein levels were analyzed. Results: Compared to wild type littermates, ALK1 +/- mice developed less inflammation and fibrosis at 20 weeks after irradiation, but displayed an increase in pro-inflammatory and pro-fibrotic gene expression at 30 weeks. In addition, ALK1 +/- mice showed superior vascular integrity at 10 and 20 weeks after irradiation which deteriorated at 30 weeks coinciding with changes in the VEGF pathway. Conclusions: ALK1 +/- mice develop a delayed normal tissue response by modulating the inflammatory response and growth factor expression after irradiation.

  12. The irradiation induced creep of graphite under accelerated damage produced by boron doping

    International Nuclear Information System (INIS)

    Brocklehurst, J.E.

    1975-01-01

    The presence of boron enhances fast neutron irradiation damage in graphite by providing nucleation sites for interstitial loop formation. Doping with 11 B casues an increase in the irradiation induced macroscopic dimensional changes, which have been shown to result from an acceleration in the differential crystal growth rate for a given carbon atom displacement rate. Models of irradiation induced creep in graphite have centred around those in which creep is induced by internal stresses due to the anisotopic crystal growth, and those in which creep is activated by atomic displacements. A creep test on boron doped graphite has been performed in an attempt to establish which of these mechanisms is the determining factor. An isotropic nuclear graphite was doped to a 11 B concentration of 0.27 wt.%. The irradiation induced volume shrinkage rate at 750 0 C increased by a factor of 3 over that of the virgin graphite, in agreement with predictions from the earlier work, but the total creep strains were comparable in both doped and virgin samples. This observation supports the view that irradiation induced creep is dependent only on the carbon atom displacement rate and not on the internal stress level determined by the differential crystal growth rate. The implications of this result on the irradiation behaviour of graphite containing significant concentrations of boron are briefly discussed. (author)

  13. A New Understanding of Near-Threshold Damage for 200 keV Irradiation In Silicon

    International Nuclear Information System (INIS)

    Stoddard, Nathan; Duscher, Gerd J.M.; Windl, Wolfgang; Rozgonyi, G.A.

    2005-01-01

    Recently we reported room temperature point defect creation and subsequent extended defect nucleation in nitrogen-doped silicon during 200 kV electron irradiation, while identical irradiation of nitrogen-free silicon produced no effect. In this paper, first principles calculations are combined with new transmission electron microscope (TEM) observations to support a new model for elastic electron-silicon interactions in the TEM, which encompasses both nitrogen doped and nitrogen free silicon. Specifically, the nudged elastic band method was used to study the energetics along the diffusion path during an electron collision event in the vicinity of a nitrogen pair. It was found that the 0 K estimate for the energy barrier of a knock-on event is lowered from ∼12 to 6.2 eV. However, this is still inadequate to explain the observations. We therefore propose an increase in the energy barrier for Frenkel pair recombination associated with N 2 -V bonding. Concerning pure silicon, stacking fault formation near irradiation-induced holes demonstrates the participation of bulk processes. In low oxygen float zone material, 2--5 nm voids were formed, while oxygen precipitation in Czochralski Si has been verified by electron energy-loss spectroscopy. Models of irradiation-induced point defect aggregation are presented and it is concluded that these must be bulk and not surface mediated phenomena.

  14. Physicochemical Study of Irradiated polypropylene/Organo :Modified Montmorillonite Composites by Using Electron Beam Irradiation Technique

    International Nuclear Information System (INIS)

    Hassan, M.S.

    2008-01-01

    Polypropylene/ Organo modified montmorillonite composites (PP/ OMMT) were prepared by melt blending with a twin screw extruder. The thermal properties by thermo gravimetric analysis (TGA), the dispersion of OMMT of macromolecules by X-ray diffraction (XRD), mechanical properties and the morphology by scanning electron microscopy (SEM) were investigated. The effect of electron beam irradiation on these properties was also studied. The results showed an intercalation between the silicate layers and the PP polymer matrix. The (PP/ OMMT) composites exhibit higher thermal stability and lower mechanical properties than pure polypropylene

  15. Oxidative decomposition of aromatic hydrocarbons by electron beam irradiation

    Science.gov (United States)

    Han, Do-Hung; Stuchinskaya, Tatiana; Won, Yang-Soo; Park, Wan-Sik; Lim, Jae-Kyong

    2003-05-01

    Decomposition of aromatic volatile organic compounds (VOCs) under electron beam irradiation was studied in order to examine the kinetics of the process, to characterize the reaction product distribution and to develop a process of waste gas control technology. Toluene, ethylbenzene, o-, m-, p-xylenes and chlorobenzene were used as target materials. The experiments were carried out at doses ranging from 0.5 to 10 kGy, using a flow reactor utilized under electron beam irradiation. Maximum degrees of decomposition carried out at 10 kGy in air environment were 55-65% for “non-chlorinated” aromatic VOC and 85% for chlorobenzene. It was found that a combination of aromatic pollutants with chlorobenzene would considerably increase the degradation value up to nearly 50% compared to the same compounds in the absence of chlorine groups. Based on our experimental observation, the degradation mechanism of the aromatic compounds combined with chloro-compound suggests that a chlorine radical, formed from EB irradiation, induces a chain reaction, resulting in an accelerating oxidative destruction of aromatic VOCs.

  16. Discussion on the re-irradiated fuel assembly with damaged guide vanes

    International Nuclear Information System (INIS)

    Li Ligang

    2013-01-01

    In January 2011, during the second plant of CNNC Nuclear Power Operations Management Co., Ltd.(hereinafter referred to as the second plant) refueling outage, the visual inspection found the guide vanes of fuel assembly A had felling off. After the National Nuclear Safety Administration (NNSA) estimated and approved, the fuel assembly A was reloaded in the specified location of reactor core. During the refueling outage in March 2012, the fuel assembly A was removed again from the reactor core. Visual inspection confirmed that the fuel assembly A was complete and without abnormal changes. The practice provides reference for re-irradiated of fuel assembly with the same type of damaged guide vanes, and provides case support for standard development for the same type of re-irradiated fuel assembly with damaged guide vanes. (author)

  17. Role of isolated and clustered DNA damage and the post-irradiating repair process in the effects of heavy ion beam irradiation

    International Nuclear Information System (INIS)

    Tokuyama, Yuka; Terato, Hiroaki; Furusawa, Yoshiya; Ide, Hiroshi; Yasui, Akira

    2015-01-01

    Clustered DNA damage is a specific type of DNA damage induced by ionizing radiation. Any type of ionizing radiation traverses the target DNA molecule as a beam, inducing damage along its track. Our previous study showed that clustered DNA damage yields decreased with increased linear energy transfer (LET), leading us to investigate the importance of clustered DNA damage in the biological effects of heavy ion beam radiation. In this study, we analyzed the yield of clustered base damage (comprising multiple base lesions) in cultured cells irradiated with various heavy ion beams, and investigated isolated base damage and the repair process in post-irradiation cultured cells. Chinese hamster ovary (CHO) cells were irradiated by carbon, silicon, argon and iron ion beams with LETs of 13, 55, 90 and 200 keV µm -1 , respectively. Agarose gel electrophoresis of the cells with enzymatic treatments indicated that clustered base damage yields decreased as the LET increased. The aldehyde reactive probe procedure showed that isolated base damage yields in the irradiated cells followed the same pattern. To analyze the cellular base damage process, clustered DNA damage repair was investigated using DNA repair mutant cells. DNA double-strand breaks accumulated in CHO mutant cells lacking Xrcc1 after irradiation, and the cell viability decreased. On the other hand, mouse embryonic fibroblast (Mef) cells lacking both Nth1 and Ogg1 became more resistant than the wild type Mef. Thus, clustered base damage seems to be involved in the expression of heavy ion beam biological effects via the repair process. (author)

  18. Electron arc therapy: chest wall irradiation of breast cancer patients

    International Nuclear Information System (INIS)

    McNeely, L.K.; Jacobson, G.M.; Leavitt, D.D.; Stewart, J.R.

    1988-01-01

    From 1980 to October 1985 we treated 45 breast cancer patients with electron arc therapy. This technique was used in situations where optimal treatment with fixed photon or electron beams was technically difficult: long scars, recurrent tumor extending across midline or to the posterior thorax, or marked variation in depth of target tissue. Forty-four patients were treated following mastectomy: 35 electively because of high risk of local failure, and 9 following local recurrence. One patient with advanced local regional disease was treated primarily. The target volume boundaries on the chest wall were defined by a foam lined cerrobend cast which rested on the patient during treatment, functioning as a tertiary collimator. A variable width secondary collimator was used to account for changes in the radius of the thorax from superior to inferior border. All patients had computerized tomography performed to determine Internal Mammary Chain depth and chest wall thickness. Electron energies were selected based on these thicknesses and often variable energies over different segments of the arc were used. The chest wall and regional node areas were irradiated to 45 Gy-50 Gy in 5-6 weeks by this technique. The supraclavicular and upper axillary nodes were treated by a direct anterior photon field abutted to the superior edge of the electron arc field. Follow-up is from 10-73 months with a median of 50 months. No major complications were observed. Acute and late effects and local control are comparable to standard chest wall irradiation. The disadvantages of this technique are that the preparation of the tertiary field defining cast and CT treatment planning are labor intensive and expensive. The advantage is that for specific clinical situations large areas of chest wall with marked topographical variation can be optimally, homogeneously irradiated while sparing normal uninvolved tissues

  19. Sesamol attenuates cytogenetic damages in bone marrow cells of whole body gamma irradiated mice

    International Nuclear Information System (INIS)

    Kumar, Arun; Tamizh Selvan, G.; Adhikari, Jawahar S.; Chaudhury, N.K.

    2014-01-01

    Whole body radiation exposure cause damages to all vital organs and bone marrow is the most sensitive. Pre-treatment with antioxidant as single prophylactic dose is expected to lower induction of damages in bone marrow. In the present study we have focused on sesamol, a dietary antioxidant mediated radioprotection in bone marrow cells of gamma irradiated mice and compared with melatonin. Male C57BL/6 mice were intraperitoneally administered with sesamol (10 and 20 mg/kg body) and after 30 minutes exposed to whole body gamma radiation using 60 Co Teletherapy unit. Mice were injected with 0.2 ml of a metaphase arresting agent (0.05% colchicine) intra-peritoneally 3 hours prior to sacrifice (24 hrs. post-irradiation). Bone marrow cells were flushed out from femurs of each animal and processed for chromosomal aberration assay. Another set of experiment without colchicine injection was performed to access the DNA damage in bone marrow using alkaline comet assay. At least 100 metaphases per animal were scored under light microscope to record various aberrations and total chromosomal aberrations (TCA) was calculated. Similar measurements were performed with melatonin for comparing the efficacy of sesamol. Gamma irradiation has increased the chromatid type aberrations (break formation, fragment) and chromosomal type aberrations (ring formation, acentric) in bone marrow cells. The results have shown significant (p< 0.001) increase in TCA of irradiated mice than control. While pre-treatment of sesamol and melatonin 10 mg/kg significantly (p<0.05) reduced the TCA. The extend of protection has increased at 20 mg/kg significantly (p<0.001) as evident from the reduced TCA compared to irradiated group. Interestingly, sesamol and melatonin have shown similar extent of reduction of TCA. Thus sesamol has demonstrated strong ability to protect bone marrow at low dosage. These investigations on sesamol mediated protection in bone marrow are likely to benefit development of

  20. Correlation of beam electron and LED signal losses under irradiation and long-term recovery of lead tungstate crystals

    International Nuclear Information System (INIS)

    Batarin, V.A.; Butler, J.; Davidenko, A.M.; Derevschikov, A.A.; Goncharenko, Y.M.; Grishin, V.N.; Kachanov, V.A.; Konstantinov, A.S.; Kravtsov, V.I.; Kubota, Y.; Lukanin, V.S.; Matulenko, Y.A.; Melnick, Y.M.; Meschanin, A.P.; Mikhalin, N.E.; Minaev, N.G.; Mochalov, V.V.; Morozov, D.A.; Nogach, L.V.; Ryazantsev, A.V.; Semenov, P.A.; Semenov, V.K.; Shestermanov, K.E.; Soloviev, L.F.; Stone, S.; Uzunian, A.V.; Vasiliev, A.N.; Yakutin, A.E.; Yarba, J.

    2005-01-01

    Radiation damage in lead tungstate crystals reduces their transparency. The calibration that relates the amount of light detected in such crystals to incident energy of photons or electrons is of paramount importance to maintaining the energy resolution the detection system. We report on tests of lead tungstate crystals, read out by photomultiplier tubes, exposed to irradiation by monoenergetic electron or pion beams. The beam electrons themselves were used to measure the scintillation light output, and a blue light emitting diode (LED) was used to track variations of crystals transparency. We report on the correlation of the LED measurement with radiation damage by the beams and also show that it can accurately monitor the crystal recovery from such damage

  1. Synchrotron microbeam irradiation induces neutrophil infiltration, thrombocyte attachment and selective vascular damage in vivo

    OpenAIRE

    Br?nnimann, Daniel; Bouchet, Audrey; Schneider, Christoph; Potez, Marine; Serduc, Rapha?l; Br?uer-Krisch, Elke; Graber, Werner; von Gunten, Stephan; Laissue, Jean Albert; Djonov, Valentin

    2016-01-01

    International audience; Our goal was the visualizing the vascular damage and acute inflammatory response to micro-and minibeam irradiation in vivo. Microbeam (MRT) and minibeam radiation therapies (MBRT) are tumor treatment approaches of potential clinical relevance, both consisting of parallel X-ray beams and allowing the delivery of thousands of Grays within tumors. We compared the effects of microbeams (25– 100 μm wide) and minibeams (200–800 μm wide) on vasculature, inflammation and surro...

  2. New crosslinked polyvinyl chloride insulated wire by electron beam irradiation

    International Nuclear Information System (INIS)

    Takahata, Norio; Shingyouchi, Kazuo; Sato, Masakatsu; Sasaki, Hidemi; Terunuma, Haruji

    1978-01-01

    The polyvinyl chloride-coated wires crosslinked by electron beam irradiation have made rapid progress as electric and electronic wiring material and grown to hold a firm position in this field. In response to the requirements for wires with the advance of electronic equipments, Hitachi Cable Ltd. developed a peculiar graft polymer consisting of chlorinated polyethylene and polyvinyl chloride. To this polymer, the characteristics of a very wide range from toughness to flexibility can be given, and the crosslinked polyvinyl chloride wires utilizing these characteristics were put in practical use. Many kinds of the wires were developed as follows; 105 deg. C rating crosslinked vinyl-coated wires authorized by UL and CSA standards, crosslinked vinyl-coated wires with excellent flexibility, high strength crosslinked vinyl-coated wires with thin coating and crosslinked vinyl-coated wires for automobiles. They are expected to be developed into other new fields and applications. (Kobatake, H.)

  3. A set of dosimetry systems for electron beam irradiation

    International Nuclear Information System (INIS)

    Lin Min; Lin Jingwen; Chen Yundong; Li Huazhi; Xiao Zhenhong; Gao Juncheng

    1999-01-01

    To follow the rapid development of radiation processing with electron beams, it is urgent to set up a set of dosimetric standards to provide Quality Assurance (QA) of electron beam irradiation and unify the values of the quality of the absorbed dose measurements for electron beams. This report introduces a set of dosimetry systems established in Radiometrology Center of China Institute of Atomic Energy (RCCIAE), which have been or will be used as dosimetric standards in the Nuclear Industry System (NIS) in China. For instance, the potassium (silver) dichromate and ceric-cerous sulfate dosimetry systems will be used as standard dosimeters, while alanine-ESR dosimetry system as a transfer dosimeter, and FJL-01 CTA as a routine dosimeter. (author)

  4. Comparison of three techniques for skin total irradiation with electrons

    International Nuclear Information System (INIS)

    Batista, Delano V.S.; Bardella, Lucia H.; Rosa, Luiz A.R. da

    2011-01-01

    This paper compared three techniques of skin total irradiation with electrons: 1) horizontal positioning, 2) vertical positioning - rotatory technique and 3) vertical positioning - six fields technique. For that, a anthropomorphic phantom was positioned according to the recommendation for each technique and was i radiated at the linear accelerator by using the 6 MeV electrons. Radiochromic films were positioned on the surface in various regions of the phantom for measurement of absorbed dose. A ionization chamber was positioned inside of equivalent issue plates for dose evaluation due to the photons produced by electron stopping. The technique 2 and 3 have shown too similar in the results and number or discrepant points (8 and 10 respectively) of prescription lower than the technique 1 (22 points). The total body dose of photons of the 1, 2 and 3 techniques was 2.2%, 5.3% and 5.2% respectively

  5. Study of irradiation damage by fast neutrons in samples of Portland cement

    International Nuclear Information System (INIS)

    Lucki, G.; Rosa Junior, A.A.

    1984-01-01

    The effect of neutron irradiation in samples of Portland cement was evaluated, using the resonance frequency method and pulse velocity of ultra-sound techniques. The samples were divided in three groups: 1) monitoring samples; 2) samples submitted to gamma heating; 3) Irradiated samples. In the sample preparation, it was used the Portland Santa Rita CP 320 cement, and water-cement rate of 0.40 l/Kg. The irradiation was done in the research reactor IEA-R1, at IPEN - CNEN/SP, with an integrated flux of 7.2 x 10 18 n/cm 2 (E approx. 1 MeV). Some damage were detected, due to the neutron flux, and by the thermal effect of gamma heating. (E.G.) [pt

  6. Irradiation damage to the gonads caused by radiotherapy of benign diseases. Pt. 2

    International Nuclear Information System (INIS)

    Hassenstein, E.; Nuesslin, F.

    1976-01-01

    The irradiation damage to the gonads caused by the radiotherapy of parotiditis and mastitis and of cheloids was determined partially under different irradiation methods. The measurements were carried out with LiF dosimeters in the Alderson phantom with a tube tension of 250 kV for the inflammatory diseases and 55 kV for the cheloids. The gonad dose measured at the surface was within the range of hundreths of permille for the parotiditis, for the mastitis it was between tenths of permille and 2 0 / 00 depending on the therapy method. The gonad dose of the cheloid irradiations showed a clear relation to the distance between radiation source and gonads. The importance of radiation protection is emphasized. (orig.) [de

  7. Irradiation damage of ferritic/martensitic steels: Fusion program data applied to a spallation neutron source

    International Nuclear Information System (INIS)

    Klueh, R.L.

    1997-01-01

    Ferritic/martensitic steels were chosen as candidates for future fusion power plants because of their superior swelling resistance and better thermal properties than austenitic stainless steels. For the same reasons, these steels are being considered for the target structure of a spallation neutron source, where the structural materials will experience even more extreme irradiation conditions than expected in a fusion power plant first wall (i.e., high-energy neutrons that produce large amounts of displacement damage and transmutation helium). Extensive studies on the effects of neutron irradiation on the mechanical properties of ferritic/martensitic steels indicate that the major problem involves the effect of irradiation on fracture, as determined by a Charpy impact test. There are indications that helium can affect the impact behavior. Even more helium will be produced in a spallation neutron target material than in the first wall of a fusion power plant, making helium effects a prime concern for both applications. 39 refs., 10 figs

  8. Standardization of accelerator irradiation procedures for simulation of neutron induced damage in reactor structural materials

    Science.gov (United States)

    Shao, Lin; Gigax, Jonathan; Chen, Di; Kim, Hyosim; Garner, Frank A.; Wang, Jing; Toloczko, Mychailo B.

    2017-10-01

    Self-ion irradiation is widely used as a method to simulate neutron damage in reactor structural materials. Accelerator-based simulation of void swelling, however, introduces a number of neutron-atypical features which require careful data extraction and, in some cases, introduction of innovative irradiation techniques to alleviate these issues. We briefly summarize three such atypical features: defect imbalance effects, pulsed beam effects, and carbon contamination. The latter issue has just been recently recognized as being relevant to simulation of void swelling and is discussed here in greater detail. It is shown that carbon ions are entrained in the ion beam by Coulomb force drag and accelerated toward the target surface. Beam-contaminant interactions are modeled using molecular dynamics simulation. By applying a multiple beam deflection technique, carbon and other contaminants can be effectively filtered out, as demonstrated in an irradiation of HT-9 alloy by 3.5 MeV Fe ions.

  9. Damage behavior in helium-irradiated reduced-activation martensitic steels at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Fengfeng [Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Guo, Liping, E-mail: guolp@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Chen, Jihong; Li, Tiecheng; Zheng, Zhongcheng [Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Yao, Z. [Department of Mechanical and Materials Engineering, Queen’s University, Kingston K7L 3N6, ON (Canada); Suo, Jinping [State Key Laboratory of Mould Technology, Institute of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2014-12-15

    Dislocation loops induced by helium irradiation at elevated temperatures in reduced-activation martensitic steels were investigated using transmission electron microscopy. Steels were irradiated with 100 keV helium ions to 0.8 dpa between 300 K and 723 K. At irradiation temperatures T{sub irr} ⩽ 573 K, small defects with both Burger vectors b = 1/2〈1 1 1〉 and b = 〈1 0 0〉 were observed, while at T{sub irr} ⩾ 623 K, the microstructure was dominated by large convoluted interstitial dislocation loops with b = 〈1 0 0〉. Only small cavities were found in the steels irradiated at 723 K.

  10. Radiation damage and deuterium trapping in deuterium-ion-irradiated Fe–9Cr alloy

    Energy Technology Data Exchange (ETDEWEB)

    Iwakir, Hirotomo, E-mail: iwakiri@edu.u-ryukyu.ac.jp [Faculty and Graduate School of Education, University of the Ryukyus, Nishihara, Okinawa 903-0213 (Japan); Tani, Munechika [Interdisciplinary Graduate School of Engineering Sciences, Kyusyu University, Kasuga, Fukuoka 816-8580 (Japan); Watanabe, Yoshiyuki [Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212 (Japan); Yoshida, Naoaki [Research Institute for Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan)

    2014-01-15

    Thermal desorption of deuterium (D{sub 2}) from deuterium-ion (D{sub 2}{sup +})-irradiated Fe–9Cr was correlated with the microstructural evolution of the alloy during irradiation with 8-keV D{sub 2}{sup +} ions following annealing to determine the retention and desorption behavior of the implanted deuterium and to identify effective traps for them, particularly at high temperature. After irradiation at 573 K, a new desorption stage formed between 650 and 1100 K at higher fluences, and cavities were observed using transmission electron microscopy. The total amount of trapped deuterium following irradiation with a fluence of 3.0 × 10{sup 22} ions/m{sup 2} was 6.8 × 10{sup 17} D{sub 2}/m{sup 2}, or approximately 0.007%. These results indicate that the deuterium atoms recombined to form D{sub 2} molecules at the surfaces of the cavities.

  11. Evaluation of damage induced by high irradiation levels on α-Ni-Ni3Si eutectic structure

    Science.gov (United States)

    Camacho Olguin, Carlos Alberto; Garcia-Borquez, Arturo; González-Rodríguez, Carlos Alberto; Loran-Juanico, Jose Antonio; Cruz-Mejía, Hector

    2015-06-01

    Diluted alloys of the binary system Ni-Si have been used as target of beam of ions, electrons, neutrons and so on because in this kind of alloy occurs transformations order-disorder, when the temperature is raised. This fact has permitted to evaluate the phenomena associated with the damage induced by irradiation (DII). The results of these works have been employed to understand the behavior under irradiation of complex alloys and to evaluate the reliability of the results of mathematical simulation of the evolution of the DII. The interest in the alloy system Ni-Si has been reborn due to the necessity of developing materials, which have better resistance against the corrosion on more aggressive environments such as those generated on the nuclear power plants or those that exist out of the Earth's atmosphere. Now, a growing interest to use concentrated alloys of this binary system on diverse fields of the materials science has been taking place because up to determined concentration of silicon, a regular eutectic is formed, and this fact opens the possibility to develop lamellar composite material by directional solidification. However, nowadays, there is a lack of fundamental knowledge about the behavior of this type of lamellar structure under aggressive environments, like those mentioned before. Hence, the task of this work is to evaluate the effect that has the irradiation over the microstructure of the concentrated alloy Ni22at%Si. The dendritic region of the hypereutectic alloy consists of an intermetallic phase Ni3Si, whereas the interdendritic region is formed by the alternation of lamellas of solid solution α-Ni and intermetallic phase Ni3Si. Such kind of microstructure has the advantage to get information of the DII over different phases individually, and at the same time, about of the microstructure influence over the global damage in the alloy. The hypereutectic Ni22at%Si alloy was irradiated perpendicularly to its surface, with 3.66 MeV - Ni ions up

  12. Radiation Safety of Gamma, Electron and X Ray Irradiation Facilities. Specific Safety Guide (Spanish Edition)

    International Nuclear Information System (INIS)

    2015-01-01

    The objective of this Safety Guide is to provide recommendations on how to meet the requirements of the BSS with regard to irradiation facilities. This Safety Guide provides specific, practical recommendations on the safe design and operation of gamma, electron and X ray irradiators for use by operating organizations and the designers of these facilities, and by regulatory bodies. SCOPE. The facilities considered in this publication include five types of irradiator, whether operated on a commercial basis or for research and development purposes. This publication is concerned with radiation safety issues and not with the uses of irradiators, nor does it cover the irradiation of product or its quality management. The five types of irradiator are: - Panoramic dry source storage irradiators; - Underwater irradiators, in which both the source and the product being irradiated are under water; - Panoramic wet source storage irradiators; - Electron beam irradiation facilities, in which irradiation is performed in an area that is potentially accessible to personnel, but that is kept inaccessible during the irradiation process; - X ray irradiation facilities, in which irradiation is performed in an area that is potentially accessible to personnel, but that is kept inaccessible during the irradiation process. Consideration of non-radiation-related risks and of the benefits resulting from the operation of irradiators is outside the scope of this Safety Guide. The practices of radiotherapy and radiography are also outside the scope of this Safety Guide. Category I gamma irradiators (i.e. 'self-shielded' irradiators) are outside the scope of this Safety Guide

  13. Electron-irradiation-induced crystallization of amorphous orthophosphates

    International Nuclear Information System (INIS)

    Meldrum, A.; Ewing, R.C.; Boatner, L.A.

    1996-12-01

    Amorphous LaPO 4 , EuPO 4 , GdPO 4 , ScPO 4 , and fluorapatite [Ca 5 (PO 4 ) 3 F] were irradiated by electron beam in a TEM. Irradiations were done at -150 to 300 C, 80 to 200 keV, and current densities from 0.3 to 16 A/cm 2 . In all cases, the materials crystallized to form a randomly oriented polycrystalline assemblage. Crystallization is driven dominantly by inelastic processes, although ballistic collisions with target nuclei can be important above 175 keV, particularly in apatite. Using a high current density, crystallization is so fast that continuous lines of crystallites can be ''drawn'' on the amorphous matrix

  14. Electron spin resonance intercomparison studies on irradiated foodstuffs

    International Nuclear Information System (INIS)

    Raffi, J.

    1992-01-01

    The results of intercomparison studies organized by the Community Bureau of Reference on the use of electron spin resonance spectroscopy for the identification of irradiated food are presented. A qualitative intercomparison was carried out using beef and trout bones, sardine scales, pistachio nut shells, dried grapes and papaya. A quantitative intercomparison involving the use of poultry bones was also organized. There was no difficulty in identifying meat bones, dried grapes and papaya. In the case of fish bones there is a need for further kinetic studies using different fish species. The identification of pistachio nut shells is more complicated and further research is needed prior to the organization of a further intercomparison. Laboratories were able to distinguish between chicken bones irradiated in the range 1 to 3 KGy or 7 to 10 KGy although there was a partial overlap between the results from different laboratories

  15. Electron spin resonance intercomparison studies on irradiated foodstuffs

    Energy Technology Data Exchange (ETDEWEB)

    Raffi, J [CEA Centre d` Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (FR)

    1992-07-01

    The results of intercomparison studies organized by the Community Bureau of Reference on the use of electron spin resonance spectroscopy for the identification of irradiated food are presented. A qualitative intercomparison was carried out using beef and trout bones, sardine scales, pistachio nut shells, dried grapes and papaya. A quantitative intercomparison involving the use of poultry bones was also organized. There was no difficulty in identifying meat bones, dried grapes and papaya. In the case of fish bones there is a need for further kinetic s