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Sample records for investigate radiation damage

  1. Investigation of solar cell radiation damage

    International Nuclear Information System (INIS)

    Bernard, J.; Reulet, R.; Arndt, R.A.

    1974-01-01

    Development of communications satellites has led to the requirement for a greater and longer lived solar cell power source. Accordingly, studies have been undertaken with the aim of determining which solar cell array provides the greatest power at end of life and the amount of degradation. Investigation of the damage done to thin silicon and thin film CdS solar cells is being carried out in two steps. First, irradiations were performed singly with 0.15, 1.0 and 2.0MeV electrons and 0.7, 2.5 and 22MeV proton. Solar cells and their cover materials were irradiated separately in order to locate the sites of the damage. Diffusion length and I.V. characteristics of the cells and transmission properties of the cover materials were measured. All neasurements were made in vacuum immediately after irradiation. In the second part it is intended to study the effect of various combinations of proton, electron and photon irradiation both with and without an electrical load. The results of this part show whether synergism is involved in solar cell damage and the relative importance of each of three radiation sources if synergism is found [fr

  2. Investigations into radiation damages of reactor materials by computer simulation

    International Nuclear Information System (INIS)

    Bronnikov, V.A.

    2004-01-01

    Data on the state of works in European countries in the field of computerized simulation of radiation damages of reactor materials under the context of the international projects ITEM (European Database for Multiscale Modelling) and SIRENA (Simulation of Radiation Effects in Zr-Nb alloys) - computerized simulation of stress corrosion when contact of Zr-Nb alloys with iodine are presented. Computer codes for the simulation of radiation effects in reactor materials were developed. European Database for Multiscale Modelling (EDAM) was organized using the results of the investigations provided in the ITEM project [ru

  3. 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

  4. Investigation of damage mechanism by ionising radiation on biomolecules

    International Nuclear Information System (INIS)

    Lau How Mooi

    1996-01-01

    Occupational radiation hazard is a very controversial subject. Effects from high radiation doses are well known from past experiences. However, hazard from low doses is still a subject that is hotly debated upon until now. The occupational dosimetry used now is based on a macroscopic scale. Lately, microdosimetry is fast gaining recognition as a more superior way of measuring hazard. More importantly, scientists are researching the basic damage mechanism that leads to biological effects by ionising radiation. In this report, a simulation study of the basic damage mechanism is discussed . This simulation is based upon Monte Carlo calculations and using polyuridylic acid (Poly-U) as the DNA model This simulation tries to relate the physics and chemistry of interactions of ionising radiation with biomolecules. The computer codes used in this simulation, OREC and RADLYS were created by Hamm et al. (1983) in Oak Ridge National Laboratory. The biological endpoints in this simulation are the strand break and base release of the DNA, which is the precursor of all biological effects. These results are compared with model studies that had been done experimentally to check the validity of this simulation. The G-values of strand break and base release from this simulation were -2.35 and 2.75 and compared well with results from irradiation experiments by von Sonntag (I 98 7) from Max Plank's Institute, Germany

  5. Radiation damage

    CERN Document Server

    Heijne, Erik H M; CERN. Geneva

    1998-01-01

    a) Radiation damage in organic materials. This series of lectures will give an overview of radiation effects on materials and components frequently used in accelerator engineering and experiments. Basic degradation phenomena will be presented for organic materials with comprehensive damage threshold doses for commonly used rubbers, thermoplastics, thermosets and composite materials. Some indications will be given for glass, scintillators and optical fibres. b) Radiation effects in semiconductor materials and devices. The major part of the time will be devoted to treat radiation effects in semiconductor sensors and the associated electronics, in particular displacement damage, interface and single event phenomena. Evaluation methods and practical aspects will be shown. Strategies will be developed for the survival of the materials under the expected environmental conditions of the LHC machine and detectors. I will describe profound revolution in our understanding of black holes and their relation to quantum me...

  6. 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)

  7. Role of noble metal nanoparticles in DNA base damage and catalysis: a radiation chemical investigation

    International Nuclear Information System (INIS)

    Sharma, Geeta K.

    2011-01-01

    In the emerging field of nanoscience and nanotechnology, tremendous focus has been made by researcher to explore the applications of nanomaterials for human welfare by converting the findings into technology. Some of the examples have been the use of nanoparticles in the field of opto-electronic, fuel cells, medicine and catalysis. These wide applications and significance lies in the fact that nanoparticles possess unique physical and chemical properties very different from their bulk precursors. Numerous methods for the synthesis of noble nanoparticles with tunable shape and size have been reported in literature. The goal of our group is to use different methods of synthesis of noble metal nanoparticles (Au, Ag, Pt and Pd) and test their protective/damaging role towards DNA base damage induced by ionizing radiation (Au and Ag) and to test the catalytic activity of nanoparticles (Pt and Pd) in certain known organic synthesis/electron transfer reactions. Using radiation chemical techniques such as pulse radiolysis and steady state radiolysis complemented by the product analysis using HPLC/LC-MS, a detailed mechanism for the formation of transient species, kinetics leading to the formation of stable end products is studied in the DNA base damage induced by ionizing radiation in presence and absence of Au and Ag nanoparticles. Unraveling the complex interaction between catalysts and reactants under operando conditions is a key step towards gaining fundamental insight in catalysis. The catalytic activity of Pt and Pd nanoparticles in electron transfer and Suzuki coupling reactions has been determined. Investigations are currently underway to gain insight into the interaction between catalysts and reactants using time resolved spectroscopic measurements. These studies will be detailed during the presentation. (author)

  8. Radiation damage prediction system using damage function

    International Nuclear Information System (INIS)

    Tanaka, Yoshihisa; Mori, Seiji

    1979-01-01

    The irradiation damage analysis system using a damage function was investigated. This irradiation damage analysis system consists of the following three processes, the unfolding of a damage function, the calculation of the neutron flux spectrum of the object of damage analysis and the estimation of irradiation effect of the object of damage analysis. The damage function is calculated by applying the SAND-2 code. The ANISN and DOT3, 5 codes are used to calculate neutron flux. The neutron radiation and the allowable time of reactor operation can be estimated based on these calculations of the damage function and neutron flux. The flow diagram of the process of analyzing irradiation damage by a damage function and the flow diagram of SAND-2 code are presented, and the analytical code for estimating damage, which is determined with a damage function and a neutron spectrum, is explained. The application of the irradiation damage analysis system using a damage function was carried out to the core support structure of a fast breeder reactor for the damage estimation and the uncertainty evaluation. The fundamental analytical conditions and the analytical model for this work are presented, then the irradiation data for SUS304, the initial estimated values of a damage function, the error analysis for a damage function and the analytical results are explained concerning the computation of a damage function for 10% total elongation. Concerning the damage estimation of FBR core support structure, the standard and lower limiting values of damage, the permissible neutron flux and the allowable years of reactor operation are presented and were evaluated. (Nakai, Y.)

  9. Investigation of radiation damage to biological specimens at water window wavelengths

    International Nuclear Information System (INIS)

    Foster, G.F.; Buckley, C.J.; Burge, R.E.; Bennett, P.M.

    1992-01-01

    This article reports the continuation of a series of experiments investigating the effects of soft x-ray radiation damage on the contractile elements of mammalian striated muscle (myofibrils), using their ability to contract as a functional assay. The myofibrils were exposed to 385 eV x rays. This energy is within the ''water window'' between the oxygen and carbon K edges, where the x-ray absorption coefficient of biological materials, such as protein, is about an order of magnitude greater than that for water. An exposure of 8x10 5 photons μm -1 was found to prevent contraction in the majority of myofibrils. Preliminary results indicate that it is possible to increase this exposure level by approximately 25% by adding the radioprotective dimethyl sulphoxide (DMSO), an OH radical scavenger to the myofibril buffer during irradiation. This suggests that OH radicals are important in the inactivation of myofibrils through irradiation

  10. Radiation damage of nonmetallic solids

    International Nuclear Information System (INIS)

    Goland, A.N.

    1975-01-01

    A review of data and information on radiation damage in nonmetallic solids is presented. Discussions are included on defects in nonmetals, radiation damage processes in nonmetals, electronic damage processes, physical damage processes, atomic displacement, photochemical damage processes, and ion implantation

  11. Radiation damage to mushrooms

    International Nuclear Information System (INIS)

    Sattler, P.W.

    1986-01-01

    This document contains newspaper cuttings and correspondence with various ministries in Hessen on the subject of radiation damage to mushrooms from the Odenwald area. The reader is given, amongst other things, detailed information on radiation damage to different types of mushroom in 1986. (MG) [de

  12. Investigations of antioxidant-mediated protection and mitigation of radiation-induced DNA damage and lipid peroxidation in murine skin.

    Science.gov (United States)

    Jelveh, Salomeh; Kaspler, Pavel; Bhogal, Nirmal; Mahmood, Javed; Lindsay, Patricia E; Okunieff, Paul; Doctrow, Susan R; Bristow, Robert G; Hill, Richard P

    2013-08-01

    Radioprotection and mitigation effects of the antioxidants, Eukarion (EUK)-207, curcumin, and the curcumin analogs D12 and D68, on radiation-induced DNA damage or lipid peroxidation in murine skin were investigated. These antioxidants were studied because they have been previously reported to protect or mitigate against radiation-induced skin reactions. DNA damage was assessed using two different assays. A cytokinesis-blocked micronucleus (MN) assay was performed on primary skin fibroblasts harvested from the skin of C3H/HeJ male mice 1 day, 1 week and 4 weeks after 5 Gy or 10 Gy irradiation. Local skin or whole body irradiation (100 kVp X-rays or caesium (Cs)-137 γ-rays respectively) was performed. DNA damage was further quantified in keratinocytes by immunofluorescence staining of γ-histone 2AX (γ-H2AX) foci in formalin-fixed skin harvested 1 hour or 1 day post-whole body irradiation. Radiation-induced lipid peroxidation in the skin was investigated at the same time points as the MN assay by measuring malondialdehyde (MDA) with a Thiobarbituric acid reactive substances (TBARS) assay. None of the studied antioxidants showed significant mitigation of skin DNA damage induced by local irradiation. However, when EUK-207 or curcumin were delivered before irradiation they provided some protection against DNA damage. In contrast, all the studied antioxidants demonstrated significant mitigating and protecting effects on radiation-induced lipid peroxidation at one or more of the three time points after local skin irradiation. Our results show no evidence for mitigation of DNA damage by the antioxidants studied in contrast to mitigation of lipid peroxidation. Since these agents have been reported to mitigate skin reactions following irradiation, the data suggest that changes in lipid peroxidation levels in skin may reflect developing skin reactions better than residual post-irradiation DNA damage in skin cells. Further direct comparison studies are required to confirm

  13. Ultrastructural investigations of meiosis as a tool in assessing radiation damage in man

    Energy Technology Data Exchange (ETDEWEB)

    Bojko, M.

    1985-01-01

    Part I is an introduction to the problems of assessing the short-term effects of ionizing radiation on human meiosis. Part II is an investigation of the ultrastructure of human oocytes at pachytene and diplotene stages of meiotic prophase. Processes leading to crossing over and chiasma formation in the female are compared with those in the male and in other organisms. Part III is a study of short-term effects of ..gamma.. radiation on spermatocytes in larvae of the silk moth, Bombyx mori.

  14. Ultrastructural investigations of meiosis as a tool in assessing radiation damage in man

    International Nuclear Information System (INIS)

    Bojko, M.

    1985-11-01

    Part I is an introduction to the problems of assesing the short-term effects of ionizing radiation on human meiosis. Part II is an investigation of the ultrastructure of human oocytes at pachytene and diplotene stages of meiotic prophase. Processes leading to crossing over and chiasma formation in the female are compared with those in the male and in other organisms. Part III is a study of short-term effects of γ radiation on spermatocytes in larvae of the silk moth, Bombyx mori. (eg)

  15. Investigations of the effect of exogenous gibberellin on the electrophoretic repair of plant DNA damaged by the gamma radiation

    International Nuclear Information System (INIS)

    Kryukova, L.M.; Medvedkova, V.V.

    1981-01-01

    Effect of the exogenous gibberellin on the DNA of plants irradiated with high doses of γ-radiation is studied. Repair of the molecular weight of DNA can be judged on according to electrophoretic mobility in 1% agar sludge of DNA samples denaturated in alkaline. Investigation results reaffirm that exogenous gibberellin promotes to the repair of the DNA of plants damaged with high doses of radiation. The mechanism of the effect of the hormone is not yet studied, but it is supposed that physiological action of the phytohormone is realized through the ferment systems of plants [ru

  16. Investigation of pUC19 DNA damage induced by direct and indirect effect of 7Li ions radiation

    International Nuclear Information System (INIS)

    Sui Li; Zhao Kui; Guo Jiyu; Ni Meinan; Kong Fuquan; Cai Minghui; Yang Mingjian

    2006-01-01

    The effect of direct and indirect action on DNA damage in 7 Li ions radiation is investigated. Using 7 Li ions generated by HI-13 tandem accelerator, three conditions of pUC19 plasmid DNA samples including dry, with or without mannitol are irradiated at different doses in air. These irradiated DNA samples are analyzed with atomic force microscopy (AFM) in nanometer-scale. The changes of DNA forms as the dose increases are observed. The results show that free radical is the main factor in DNA strand breaks induced by 7 Li ions radiation under condition of aqueous solution. The mannitol can effectively scavenge free radical and reduce the yields of DNA strand breaks. The experimental results of this report can offered valuable basal data for cancer therapy by boron neutron capture therapy (BNCT) or heavy ion radiation method, etc. (author)

  17. An edge-TCT setup for the investigation of radiation damaged silicon sensors

    Energy Technology Data Exchange (ETDEWEB)

    Feindt, Finn; Scharf, Christian; Garutti, Erika; Klanner, Robert [Institute for Experimental Physics, Hamburg University, Luruper Chaussee 149, D-22761 Hamburg (Germany)

    2016-07-01

    The aim of this work is to measure the electric field, drift velocity and charge collection of electrons and holes in radiation-damaged silicon strip sensors. For this purpose the edge Transient Current Technique (TCT) is employed. In contrast to conventional TCT, this method requires light from a sub-ns pulsed, infrared laser to be focused to a μm-size spot and scanned across the polished edge of a strip sensor. Thus electron-hole pairs are generated at a known depth in the sensor. Electrons and holes drift in the electric field and induce transient currents on the sensor electrodes. The current wave forms are analyzed as a function of the applied voltage and the position of the laser focus in order to determine the electric field, the drift velocities and the charge collection. In this talk the setup and the procedure for polishing the sensor edge are described, and first results, regarding the measurement of the laser light focus are presented.

  18. Radiation damage of uranium

    International Nuclear Information System (INIS)

    Lazarevic, Dj.

    1966-11-01

    Study of radiation damage covered the following: Kinetics of electric resistance of uranium and uranium alloy with 1% of molybdenum dependent on the second phase and burnup rate; Study of gas precipitation and diffusion of bubbles by transmission electron microscopy; Numerical analysis of the influence of defects distribution and concentration on the rare gas precipitation in uranium; study of thermal sedimentation of uranium alloy with molybdenum; diffusion of rare gas in metal by gas chromatography method

  19. Investigation of microscopic radiation damage in waste forms using ODNMR and AEM techniques. (EMSP Project Final Report)

    International Nuclear Information System (INIS)

    Liu, G.; Luo, J.; Beitz, J.; Li, S.; Williams, C.; Zhorin, V.

    2000-01-01

    This project seeks to understand the microscopic effects of radiation damage in nuclear waste forms. The authors' approach to this challenge encompasses studies of ceramics and glasses containing short-lived alpha- and beta-emitting actinides with electron microscopy, laser and X-ray spectroscopic techniques, and computational modeling and simulations. In order to obtain information on long-term radiation effects on waste forms, much of the effort is to investigate α-decay induced microscopic damage in 18-year old samples of crystalline yttrium and lutetium orthophosphates that initially contained ∼ 1(wt)% of the alpha-emitting isotope 244 Cm (18.1 y half life). Studies also are conducted on borosilicate glasses that contain 244 Cm, 241 Am, or 249 Bk, respectively. The authors attempt to gain clear insights into the properties of radiation-induced structure defects and the consequences of collective defect-environment interactions, which are critical factors in assessing the long-term performance of high-level nuclear waste forms

  20. Investigation of microscopic radiation damage in waste forms using ODNMR and AEM techniques. (EMSP Project Final Report)

    Energy Technology Data Exchange (ETDEWEB)

    Liu, G.; Luo, J.; Beitz, J.; Li, S.; Williams, C.; Zhorin, V.

    2000-04-21

    This project seeks to understand the microscopic effects of radiation damage in nuclear waste forms. The authors' approach to this challenge encompasses studies of ceramics and glasses containing short-lived alpha- and beta-emitting actinides with electron microscopy, laser and X-ray spectroscopic techniques, and computational modeling and simulations. In order to obtain information on long-term radiation effects on waste forms, much of the effort is to investigate {alpha}-decay induced microscopic damage in 18-year old samples of crystalline yttrium and lutetium orthophosphates that initially contained {approximately} 1(wt)% of the alpha-emitting isotope {sup 244}Cm (18.1 y half life). Studies also are conducted on borosilicate glasses that contain {sup 244}Cm, {sup 241}Am, or {sup 249}Bk, respectively. The authors attempt to gain clear insights into the properties of radiation-induced structure defects and the consequences of collective defect-environment interactions, which are critical factors in assessing the long-term performance of high-level nuclear waste forms.

  1. Radiation damage in DNA

    International Nuclear Information System (INIS)

    Lafleur, V.

    1978-01-01

    A number of experiments are described with the purpose to obtain a better insight in the chemical nature and the biological significance of radiation-induced damage in DNA, with some emphasis on the significance of alkali-labile sites. It is shown that not only reactions of OH radicals but also of H radicals introduce breaks and other inactivating damage in single-standed phiX174 DNA. It is found that phosphate buffer is very suitable for the study of the reactions of H radicals with DNA, as the H 2 PO 4 - ions convert the hydrated electrons into H radicals. The hydrated electron, which does react with DNA, does not cause a detectable inactivation. (Auth.)

  2. Investigation on the effect of developed product and new food for radiation-induced skin damage

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Ho; Kim, Jong Chun; Bae, Chun Sik; Kim, Se Ra; Lee, Hae Jun; Bang, Dae Won; Lee, Jin Hee; Kim, Joong Sun; Ki, Sun Ah; Song, Myung Seop [Chonnam National University, Gwangju (Korea, Republic of)

    2007-07-15

    In vivo evaluation of the developed pilot product on the skin protection against UV irradiation and screening of new candidate materials. Project Results are Establishment of experimental methods for 3 morphological indices of UV-induced skin damages -Establishment of experimental methods for whitening effect evaluation -Evaluation of HemoHIM administration on the skin damage indices -Evaluation of HemoHIM skin application on the skin damage indices -Evaluation of HemoTonic administration on the skin damage indices -Evaluation of HemoTonic skin application on the skin damage indices -Evaluation of HemoHIM on the antiinflamatory effects in the inflammation stage 1 -Evaluation of HemoHIM on the antiinflamatory effects in the inflammation stage 2 -Evaluation of HemoHIM on the antiinflamatory effects in the inflammation stage 3 -Evaluation of HemoHIM on the antiinflamatory effects in the TNBS-induced colitis -Evaluation of HemoHIM on the anti-wrinkle effects in the skin -Evaluation of HemoHIM on the protective effects on the skin tissue (epidermal thickening, dermal cellularity, dermal cyst) -Evaluation of HemoHIM on the protective effects on the skin tumor development

  3. Investigation on the effect of developed product and new food for radiation-induced skin damage

    International Nuclear Information System (INIS)

    Kim, Sung Ho; Kim, Jong Chun; Bae, Chun Sik; Kim, Se Ra; Lee, Hae Jun; Bang, Dae Won; Lee, Jin Hee; Kim, Joong Sun; Ki, Sun Ah; Song, Myung Seop

    2007-07-01

    In vivo evaluation of the developed pilot product on the skin protection against UV irradiation and screening of new candidate materials. Project Results are Establishment of experimental methods for 3 morphological indices of UV-induced skin damages -Establishment of experimental methods for whitening effect evaluation -Evaluation of HemoHIM administration on the skin damage indices -Evaluation of HemoHIM skin application on the skin damage indices -Evaluation of HemoTonic administration on the skin damage indices -Evaluation of HemoTonic skin application on the skin damage indices -Evaluation of HemoHIM on the antiinflamatory effects in the inflammation stage 1 -Evaluation of HemoHIM on the antiinflamatory effects in the inflammation stage 2 -Evaluation of HemoHIM on the antiinflamatory effects in the inflammation stage 3 -Evaluation of HemoHIM on the antiinflamatory effects in the TNBS-induced colitis -Evaluation of HemoHIM on the anti-wrinkle effects in the skin -Evaluation of HemoHIM on the protective effects on the skin tissue (epidermal thickening, dermal cellularity, dermal cyst) -Evaluation of HemoHIM on the protective effects on the skin tumor development

  4. Radiation damage by high-energy electrons in GaAs: DLTS investigation

    International Nuclear Information System (INIS)

    Lehmann, B.

    1991-10-01

    An isothermal variation of the DLTS technique is developed and applied to the study of displacement damage in GaAs, through the determination of threshold energies and displacement cross sections. Its results correspond to those of an LED based method. A pronounced anisotropy is found for the threshold energy. A linearly increasing displacement probability function is shown to properly model the displacement cross section in direction, as compared with the direction which requires only a single step function. Differences in the damage between these two directions are as large as a factor of two. (orig.) [de

  5. Radiation damage to histones

    International Nuclear Information System (INIS)

    Mee, L.K.; Adelstein, S.J.

    1985-01-01

    The damage to histones irradiated in isolation is being elaborated to aid the identification of the crosslinking sites in radiation-induced DNA-histone adducts. Histones are being examined by amino acid analysis to determine the destruction of residues and by polyacrylamide gel electrophoresis to delineate changes in conformation. For the slightly lysine-rich histone, H2A, a specific attack on selective residues has been established, the aromatic residues, tyrosine and phenylalanine, and the heterocyclic residue, histidine, being significantly destroyed. In addition, a significant increase in aspartic acid was found; this may represent a radiation product from scission of the ring in the histidine residues. The similarity of the effects on residues in nitrous oxide-saturated and nitrogen-saturated solutions suggests that OH . and e/sub aq//sup -/ are equally efficient and selective in their attack. On gel electrophoresis degradation of the histone H2A was found to be greatest for irradiations in nitrous oxide-saturated solutions, suggesting CH . is the most effective radical for producing changes in conformation; O/sub 2//sup -/ was essentially ineffective. Other histones are being examined for changes in amino acid composition, conformation, and for the formation of radiation products

  6. Corneal Damage from Infrared Radiation

    National Research Council Canada - National Science Library

    McCally, Russell

    2000-01-01

    ...) laser radiation at 10.6 (micrometer) and Tm: YAG laser radiation at 2.02 (micrometer). Retinal damage from sources with rectangular irradiance distributions was also modeled. Thresholds for CO(2...

  7. Radiation Damage in Scintillating Crystals

    CERN Document Server

    Zhu Ren Yuan

    1998-01-01

    Crystal Calorimetry in future high energy physics experiments faces a new challenge to maintain its precision in a hostile radiation environment. This paper discusses the effects of radiation damage in scintillating crystals, and concludes that the predominant radiation damage effect in crystal scintillators is the radiation induced absorption, or color center formation, not the loss of the scintillation light yield. The importance of maintaining crystal's light response uniformity and the feasibility to build a precision crystal calorimeter under radiation are elaborated. The mechanism of the radiation damage in scintillating crystals is also discussed. While the damage in alkali halides is found to be caused by the oxygen or hydroxyl contamination, it is the structure defects, such as oxygen vacancies, cause damage in oxides. Material analysis methods used to reach these conclusions are presented in details.

  8. Investigations of the effects of UV and X-ray radiation and the repair of radiation damage in the ciliate Stylonychia mytilus

    International Nuclear Information System (INIS)

    Dittmann, F.N.

    1978-01-01

    Using the example of Stylomychia mytilus, the effects of UV-radiation and ionizing X-ray radiation are compared. The effects on cell division and on the repair of radiation damage in DNA are compared. Sensitivity to UV radiation differs between the stages of the cell cycle while the effects of X-ray radiation are independent of phase. There is no difference in repair processes. (AJ) 891 AJ/AJ 892 MKO [de

  9. An EPR investigation of room temperature radiation damage and molecular motion in the ferroelectric phosphates

    International Nuclear Information System (INIS)

    Dalal, N.S.; Herak, J.N.; McDowell, C.A.

    1976-01-01

    Several types of paramagnetic centers have been detected in the room temperature irradiated KH 2 PO 4 , KD 2 PO 4 , KH 2 PO 4 -KH 2 AsO 4 , KD 2 PO 4 -KD 2 AsO 4 and in the newly discovered ferroelectric NaTh 2 (PO 4 ) 3 . Comparative studies of temperature dependence in the EPR spectra show that as in KH 2 PO 4 -type crystals, the ferroelectric phase transition in NaTh 2 (PO 4 ) 3 crystals also seems to be related to the motion of the PO 4 units. The results help to clarify some earlier observed anomalies on the effects of γ-irradiation on dielectric properties of KH 2 PO 4 and in particular, show that the extent of the damage can be controlled by changing the impurity content of the unirradiated samples. (Auth.)

  10. Investigation of microscopic radiation damage in waste forms using ODNMR and AEM techniques. 1998 annual progress report

    International Nuclear Information System (INIS)

    Liu, G.

    1998-01-01

    'This project seeks to understand the microscopic effects of radiation damage in nuclear waste forms. The authors approach to this challenge encompasses studies of crystals and glass containing short-lived alpha- and beta-emitting actinides with electron microscopy, laser spectroscopy, and computational modeling and simulation. Much of the initial effort has focused on alpha-decay induced microscopic damage in 17-year old samples of crystalline yttrium and lutetium orthophosphates and thorium dioxide that initially contained ∼1% of the alpha-emitting isotope Cm-244 (18.1 y half life) or the beta-emitting isotope Bk-249 (0.88 y half life). Studies will also be conducted on borosilicate glasses that contain Cm-244 or Am-241, respectively. The goal is to gain clear insight into accumulated radiation damage and the influence of aging on such damage, which are critical factors in the long-term performance of high-level nuclear waste forms. Amorphization previously has been thought to be the most important effect of radiation damage in crystalline and ceramic materials. The studies show that for alpha-emitting actinide ions in certain crystalline phosphates, amorphization is not a significant effect of radiation damage. Instead, formation of microscopic cavities (bubbles) is an important consequence of alpha-decay events. This amorphization-resistant property makes orthophosphates a very attractive high level nuclear waste form. However, aggregation and mobilization of cavities (bubbles) might increase the leach rate of radionuclides and influence the long-term stability of the waste forms. Further research is needed before the authors can draw a final conclusion on the long-term effects of radiation damage in high level waste forms.'

  11. Edge-TCT for the investigation of radiation damaged silicon strip sensors

    Energy Technology Data Exchange (ETDEWEB)

    Feindt, Finn

    2017-02-15

    The edge Transient Current Technique (TCT) is a method for the investigation of silicon sensors. This method requires infrared light from a sub-ns pulsed laser to be focused to a μm-size spot and scanned across the polished cut edge of a sensor. Electron-hole pairs are generated along the light beam in the sensor. These charge carriers drift in the electric field and induce transient currents on the sensor electrodes. The current transients are analyzed as a function of the applied voltage, temperature, absorbed dose and position of the laser-light focus, in order to determine the the drift velocities, electric field and the charge collection in the strip sensor. In the scope of this work, a new edge-TCT setup is commissioned, a procedure for the polishing of the cut edge is implemented and a method to position the focus of the laser light with respect to the sensor is developed. First edge-TCT measurements are performed on non-irradiated, 285 μm thick n-type strip sensors, and the pulse shape and charge collection is studied under different conditions. Furthermore, the prompt current of the transients is extracted, which is the first step towards the determination of the electric field. A new method to measure the attenuation of light in silicon is tested on a non-irradiated sensor and on sensors irradiated with up to a 1 MeV neutron equivalent fluence of 1.14 x 10{sup 15} cm{sup -2}, using laser light with a wavelength of 1052 nm.

  12. Edge-TCT for the investigation of radiation damaged silicon strip sensors

    International Nuclear Information System (INIS)

    Feindt, Finn

    2017-02-01

    The edge Transient Current Technique (TCT) is a method for the investigation of silicon sensors. This method requires infrared light from a sub-ns pulsed laser to be focused to a μm-size spot and scanned across the polished cut edge of a sensor. Electron-hole pairs are generated along the light beam in the sensor. These charge carriers drift in the electric field and induce transient currents on the sensor electrodes. The current transients are analyzed as a function of the applied voltage, temperature, absorbed dose and position of the laser-light focus, in order to determine the the drift velocities, electric field and the charge collection in the strip sensor. In the scope of this work, a new edge-TCT setup is commissioned, a procedure for the polishing of the cut edge is implemented and a method to position the focus of the laser light with respect to the sensor is developed. First edge-TCT measurements are performed on non-irradiated, 285 μm thick n-type strip sensors, and the pulse shape and charge collection is studied under different conditions. Furthermore, the prompt current of the transients is extracted, which is the first step towards the determination of the electric field. A new method to measure the attenuation of light in silicon is tested on a non-irradiated sensor and on sensors irradiated with up to a 1 MeV neutron equivalent fluence of 1.14 x 10"1"5 cm"-"2, using laser light with a wavelength of 1052 nm.

  13. Programmed cellular response to ionizing radiation damage

    International Nuclear Information System (INIS)

    Crompton, N.E.A.

    1998-01-01

    Three forms of radiation response were investigated to evaluate the hypothesis that cellular radiation response is the result of active molecular signaling and not simply a passive physicochemical process. The decision whether or not a cell should respond to radiation-induced damage either by induction of rescue systems, e.g. mobilization of repair proteins, or induction of suicide mechanisms, e.g. programmed cell death, appears to be the expression of intricate cellular biochemistry. A cell must recognize damage in its genetic material and then activate the appropriate responses. Cell type is important; the response of a fibroblast to radiation damage is both quantitatively and qualitatively different form that of a lymphocyte. The programmed component of radiation response is significant in radiation oncology and predicted to create unique opportunities for enhanced treatment success. (orig.)

  14. Investigation on the radiation damage behavior of various alloys in a fusion reactor using thorium molten salt

    International Nuclear Information System (INIS)

    Ubeyli, Mustafa; Demir, Teyfik

    2008-01-01

    In fusion reactors, one of the most important problems is the need for the frequent change of the first wall material during the reactor's operation due to the radiation damage induced by high energetic particles, especially fusion neutrons coming from fusion plasma. In order to solve this problem, in HYLIFE-II fusion reactor design, a liquid wall between the fusion plasma and first wall is used. This study presents the radiation damage behaviors of candidate structural materials (9Cr-2WVTa, V-4Cr-4Ti and W-5Re alloys) considered to be used in fusion reactors to determine the optimum thickness of the liquid wall in HYLIFE-II fusion reactor. In the liquid wall, a thorium molten salt consisting of 75%LiF-23%ThF 4 -2% 233 UF 4 was used. Calculations were carried out with respect to the variable liquid wall thickness and for an operation period of 30 years. Numerical results related to atomic displacement and helium generation damage pointed out that the liquid wall thickness should be at least 42, 66 and 81 cm for the materials, W-5Re, 9Cr-2WVTa, V-4Cr-4Ti, respectively in order not to exceed relevant damage limits after a reactor operation of 30 years

  15. Radiation damage in biomolecular systems

    CERN Document Server

    Fuss, Martina Christina

    2012-01-01

    Since the discovery of X-rays and radioactivity, ionizing radiations have been widely applied in medicine both for diagnostic and therapeutic purposes. The risks associated with radiation exposure and handling led to the parallel development of the field of radiation protection. Pioneering experiments done by Sanche and co-workers in 2000 showed that low-energy secondary electrons, which are abundantly generated along radiation tracks, are primarily responsible for radiation damage through successive interactions with the molecular constituents of the medium. Apart from ionizing processes, which are usually related to radiation damage, below the ionization level low-energy electrons can induce molecular fragmentation via dissociative processes such as internal excitation and electron attachment. This prompted collaborative projects between different research groups from European countries together with other specialists from Canada,  the USA and Australia. This book summarizes the advances achieved by these...

  16. Radiation damage in lithium orthosilicate

    Energy Technology Data Exchange (ETDEWEB)

    Noda, K.; Nakazawa, T.; Ishii, Y.; Fukai, K.; Watanabe, H. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment); Matsui, H.; Vollath, D.

    1993-11-01

    Radiation damage in lithium orthosilicate (Li[sub 4]SiO[sub 4]) and Al-doped Li[sub 4]SiO[sub 4] (Li[sub 3.7]Al[sub 0.1]SiO[sub 4]) irradiated with oxygen ions was studied with ionic conductivity measurements, Raman spectroscopy, Fourier transform infrared photo-acoustic spectroscopy (FT-IR PAS) and transmission electron microscopy. It was seen from the ionic conductivity measurements that lithium-ion vacancies were introduced as irradiation defects for Li-ions sites in both materials due to the irradiation. By the Raman spectroscopy, oxygen atoms in SiO[sub 4] tetrahedra were considered to be preferentially displaced due to the irradiation for Li[sub 4]SiO[sub 4], although only a decrease of the number of SiO[sub 4] tetrahedra occurred for Li[sub 3.7]Al[sub 0.1]SiO[sub 4] by displacement of both silicon and oxygen atoms. Decomposition of SiO[sub 4] tetrahedra and formation of some new phases having Si-O-Si and Si-O bonds were found to take place for both Li[sub 4]SiO[sub 4] and Li[sub 3.7]Al[sub 0.1]SiO[sub 4] by FT-IR PAS. In the electron microscopy, damage microstructure consisting of many voids or cavities and amorphization were observed for Li[sub 4]SiO[sub 4] irradiated with oxygen ions. The recovery behavior of radiation damage mentioned above was also investigated. (author).

  17. Neutron induced radiation damage

    International Nuclear Information System (INIS)

    Williams, M.M.R.

    1977-01-01

    We derive a general expression for the number of displaced atoms of type j caused by a primary knock-on of type i. The Kinchin-Pease model is used, but considerably generalised to allow for realistic atomic potentials. Two cases are considered in detail: the single particle problem causing a cascade and the neutron initiated problem which leads to multiple subcascades. Numerical results have been obtained for a variety of scattering laws. An important conclusion is that neutron initiated damage is much more severe than atom-initiated damage and leads to the number of displaced atoms being a factor of (A+1) 2 /4A larger than the single primary knock-on theory predicts. A is the ratio of the atomic mass to the neutron mass. The importance of this result to the theory of neutron sputtering is explained. (orig.) [de

  18. Radiation damages in superconducting materials

    International Nuclear Information System (INIS)

    Heinz, W.; Seibt, E.

    1978-01-01

    Radiation damage investigations of technical superconductors are reported and discussed with respect to their main properties like critical current jsub(c), transition temperature Tsub(c), upper critical field Bsub(c2), pinning and annealing behaviour. Ordered A15 type alloys (like Nb 3 Sn and V 3 Ga) show significant reductions of all critical parameters above a threshold of about 2x10 21 m -2 with 50 MeV deuterons corresponding to 2x10 22 neutrons/m 2 (Esub(n)>0.1 MeV). Pure metals and disordered B1 type alloys (like Nb or NbTi) show only a small linear decrease in critical parameters (except Bsub(c2) of niobium). Experimental results are compared with theoretical calculations. (author)

  19. An investigation into the radiation damage of the silicon detectors of the H1-PLUG calorimeter within the HERA environment

    International Nuclear Information System (INIS)

    Hildesheim, W.; Seidel, M.

    1995-07-01

    The silicon detectors used in the H1-PLUG calorimeter have shown increasing aging effects during the '94 run period of the electron proton storage ring HERA. These effects were particularly manifest as degradation of the signal to noise level and the calibration stability. The reasons for this behaviour have been found to be correlated with radiation damage to the silicon oxide passivation edges of the detectors in strong and fluctuating increases of the leakage currents and in severe changes of the flat band voltages. Depletion voltages however are found to be stable and therefore bulk damage of the silicon can be excluded. A comparison with measurements made by thermoluminescence dosimeters as well as related laboratory experiments suggest that the aging is due to very low energetic electrons and photons. (orig.)

  20. Radiation Damage and Dimensional Changes

    International Nuclear Information System (INIS)

    El-Barbary, A.A.; Lebda, H.I.; Kamel, M.A.

    2009-01-01

    The dimensional changes have been modeled in order to be accommodated in the reactor design. This study has major implications for the interpretation of damage in carbon based nuclear fission and fusion plant materials. Radiation damage of graphite leads to self-interstitials and vacancies defects. The aggregation of these defects causes dimensional changes. Vacancies aggregate into lines and disks which heal and contract the basal planes. Interstitials aggregate into interlayer disks which expand the dimension

  1. Radiation-induced liver damage

    International Nuclear Information System (INIS)

    Marcial, V.A.; Santiago-Delpin, E.A.; Lanaro, A.E.; Castro-Vita, H.; Arroyo, G.; Moscol, J.A.; Gomez, C.; Velazquez, J.; Prado, K.

    1977-01-01

    Due to the recent increase in the use of radiation therapy in the treatment of cancer with or without chemotherapy, the risk of liver radiation damage has become a significant concern for the radiotherapist when the treated tumour is located in the upper abdomen or lower thorax. Clinically evident radiation liver damage may result in significant mortality, but at times patients recover without sequelae. The dose of 3000 rads in 3 weeks to the entire liver with 5 fractions per week of 200 rads each, seems to be tolerated well clinically by adult humans. Lower doses may lead to damage when used in children, when chemotherapy is added, as in recent hepatectomy cases, and in the presence of pre-existent liver damage. Reduced fractionation may lead to increased damage. Increased fractionation, limitation of the dose delivered to the entire liver, and restriction of the high dose irradiation volume may afford protection. With the aim of studying the problems of hepatic radiation injury in humans, a project of liver irradiation in the dog is being conducted. Mongrel dogs are being conditioned, submitted to pre-irradiation studies (haemogram, blood chemistry, liver scan and biopsy), irradiated under conditions resembling human cancer therapy, and submitted to post-irradiation evaluation of the liver. Twenty-two dogs have been entered in the study but only four qualify for the evaluation of all the study parameters. It has been found that dogs are susceptible to liver irradiation damage similar to humans. The initial mortality has been high mainly due to non-radiation factors which are being kept under control at the present phase of the study. After the initial experiences, the study will involve variations in total dose and fractionation, and the addition of anticoagulant therapy for possible prevention of radiation liver injury. (author)

  2. Radiation damage in plastic scintillators

    International Nuclear Information System (INIS)

    Majewski, S.

    1990-01-01

    Results of radiation damage studies in plastic scintillators are reviewed and critically analyzed from the point of view of applications of plastic scintillators in calorimetric detectors for the SSC. Damage to transmission and to fluorescent yield in different conditions is discussed. New directions in R ampersand D are outlined. Several examples are given of the most recent data on the new scintillating materials made with old and new plastics and fluors, which are exhibiting significantly improved radiation resistance. With a present rate of a vigorous R D programme, the survival limits in the vicinity of 100 MRad seem to be feasible within a couple of years

  3. Mechanisms for radiation damage in DNA

    International Nuclear Information System (INIS)

    Sevilla, M.D.

    1993-12-01

    In this project the author has proposed several mechanisms for radiation damage to DNA and its constituents, and has detailed a series of experiments utilizing electron spin resonance spectroscopy, HPLC, GC-mass spectroscopy and ab initio molecular orbital calculations to test the proposed mechanisms. In this years work he has completed several experiments on the role of hydration water on DNA radiation damage, continued the investigation of the localization of the initial charges and their reactions on DNA, investigated protonation reactions in DNA base anions, and employed ab initio molecular orbital theory to gain insight into the initial events of radiation damage to DNA. Ab initio calculations have provided an understanding of the energetics evolved in anion and cation formation, ion radical transfer in DNA as well as proton transfer with DNA base pair radical ions. This has been extended in this years work to a consideration of ionization energies of various components of the DNA deoxyribose backbone and resulting neutral sugar radicals. This information has aided the formation of new radiation models for the effect of radiation on DNA. During this fiscal year four articles have been published, four are in press, one is submitted and several more are in preparation. Four papers have been presented at scientific meetings. This years effort will include another review article on the open-quotes Electron Spin Resonance of Radiation Damage to DNAclose quotes

  4. A tan in a test tube - in vitro models for investigating ultraviolet radiation-induced damage in skin.

    Science.gov (United States)

    Fernandez, Tara L; Dawson, Rebecca A; Van Lonkhuyzen, Derek R; Kimlin, Michael G; Upton, Zee

    2012-06-01

    Presently, global rates of skin cancers induced by ultraviolet radiation (UVR) exposure are on the rise. In view of this, current knowledge gaps in the biology of photocarcinogenesis and skin cancer progression urgently need to be addressed. One factor that has limited skin cancer research has been the need for a reproducible and physiologically-relevant model able to represent the complexity of human skin. This review outlines the main currently-used in vitro models of UVR-induced skin damage. This includes the use of conventional two-dimensional cell culture techniques and the major animal models that have been employed in photobiology and photocarcinogenesis research. Additionally, the progression towards the use of cultured skin explants and tissue-engineered skin constructs, and their utility as models of native skin's responses to UVR are described. The inherent advantages and disadvantages of these in vitro systems are also discussed. © 2012 John Wiley & Sons A/S.

  5. Radiation exposure and chromosome damage

    International Nuclear Information System (INIS)

    Lloyd, D.

    1979-01-01

    Chromosome damage is discussed as a means of biologically measuring radiation exposure to the body. Human lymphocytes are commonly used for this test since the extent of chromosome damage induced is related to the exposure dose. Several hundred lymphocytes are analysed in metaphase for chromosome damage, particularly dicentrics. The dose estimate is made by comparing the observed dicentric yield against calibration curves, previously produced by in vitro irradiation of blood samples to known doses of different types of radiation. This test is useful when there is doubt that the film badge has recorded a reasonable whole body dose and also when there is an absence of any physical data. A case of deliberate exposure is described where the chromosome damage test estimated an exposure of 152 rads. The life span of cell aberrations is also considered. Regular checks on radiotherapy patients and some accidental overdose cases have shown little reduction in the aberration levels over the first six weeks after which the damage disappears slowly with a half-life of about three years. In conclusion, chromosome studies have been shown to be of value in resolving practical problems in radiological protection. (U.K.)

  6. Tooth-germ damage by ionizing radiation

    International Nuclear Information System (INIS)

    Sobkowiak, E.M.; Beetke, E.; Bienengraeber, V.; Held, M.; Kittner, K.H.

    1977-01-01

    Experiments on animals (four-week-old dogs) were conducted in an investigation made to study the possibility of dose-dependent tooth-germ damage produced by ionizing radiation. The individual doses were 50 R and 200 R, respectively, and they were administered once to three times at weekly intervals. Hyperemia and edemata could be observed on tooth-germ pulps from 150 R onward. Both of these conditions became more acute as the radiation dose increased (from 150 R to 600 R). Possible damage to both the dentin and enamel is pointed out. (author)

  7. Dermal damage from ultraviolet radiation

    International Nuclear Information System (INIS)

    Kligman, L.H.

    1988-01-01

    Ultraviolet (UV) radiation is increasingly recognized as the cause of a vast number of changes in the skin of humans and animals. These include alterations at the molecular, cellular, tissue and systematic levels. In the recent past, much has been learned about the immediate effects in skin of acute UV exposure (i.e. sunburn) with its epidermal cell death, inflammation and vasolidation. With chronic exposure, many of the clinical and histologic effects can be seen only after decades. Visually, these are hyper- and hypopigmented macules, dry scaly, wrinkled skin with a variety of benign, pre-malignant and malignant neoplasms. All epidermal in origin, they lead, inexorably in humans, to the appearance the authors described as photo-aged. Underlying many of these visible manifestations are drastic changes in the dermis. These relate chiefly to destruction of mature collagen, with a compensatory overproduction of reticulin fibers, hyperplasia of elastic fibers eventuating in elastosis, increased levels of the glycosaminoglycans (GAGs) comprising the ground substance and changes in the microvasculature. First described in actinically damaged humans, systematic investigation required an animal model

  8. Radiation damage in silicon detectors

    CERN Document Server

    Lindström, G

    2003-01-01

    Radiation damage effects in silicon detectors under severe hadron and gamma-irradiation are surveyed, focusing on bulk effects. Both macroscopic detector properties (reverse current, depletion voltage and charge collection) as also the underlying microscopic defect generation are covered. Basic results are taken from the work done in the CERN-RD48 (ROSE) collaboration updated by results of recent work. Preliminary studies on the use of dimerized float zone and Czochralski silicon as detector material show possible benefits. An essential progress in the understanding of the radiation-induced detector deterioration had recently been achieved in gamma irradiation, directly correlating defect analysis data with the macroscopic detector performance.

  9. Differential Processing of Low and High LET Radiation Induced DNA Damage: Investigation of Switch from ATM to ATR Signaling

    Science.gov (United States)

    Saha, Janapriya; Wang, Minli; Hada, Megumi; Cucinotta, Francis A.

    2011-01-01

    The members of the phosphatidylinositol kinase-like kinase family of proteins namely ataxia-telangiectasia mutated (ATM) and ATM- and Rad3-related (ATR) are directly responsible for the maintenance of genomic integrity by mounting DDR through signaling and facilitating the recruitment of repair factors at the sites of DNA damage along with coordinating the deployment of cell cycle checkpoints to permit repair by phosphorylating Checkpoint kinase Chk1, Chk2 and p53. High LET radiation from GCR (Galactic Cosmic Rays) consisting mainly of protons and high energy and charged (HZE) particles from SPE (Solar Particle Event) pose a major health risk for astronauts on their space flight missions. The determination of these risks and the design of potential safeguards require sound knowledge of the biological consequences of lesion induction and the capability of the cells to counter them. We here strive to determine the coordination of ATM and ATR kinases at the break sites directly affecting checkpoint signaling and DNA repair and whether differential processing of breaks induced by low and high LET radiation leads to possible augmentation of swap of these damage sensors at the sites of DNA damage. Exposure of cells to IR triggers rapid autophosphorylation of serine-1981 that causes dimer dissociation and initiates monomer formation of ATM. ATM kinase activity depends on the disruption of the dimer, which allows access and phosphorylation of downstream ATM substrates like Chk2. Evidence suggests that ATM is activated by the alterations in higher-order chromatin structure although direct binding of ATM to DSB ends may be a crucial step in its activation. On the other hand, in case of ATR, RPA (replication protein A)-coated ssDNA (single-stranded DNA) generated as a result of stalled DNA replication or during processing of chromosomal lesions is crucial for the localization of ATR to sites of DNA damage in association with ATR-interacting protein (ATRIP). Although the

  10. Mechanisms for radiation damage in DNA

    International Nuclear Information System (INIS)

    Sevilla, M.D.

    1987-01-01

    Several mechanisms are proposed for radiation damage to DNA and its constituents, and a series of experiments utilizing electron spin resonance spectrometry have been used to test the proposed mechanisms. In the past we have concentrated chiefly on investigating irradiated systems of DNA constituents. In this year's effort we have concentrated on radiation effects on DNA itself. In addition studies of radiation effects on lipids and model compounds have been performed which shed light on the only other proposed site for cell kill, the membrane

  11. Radiation induced genetic damage in Aspergillus nidulans

    International Nuclear Information System (INIS)

    Georgiou, J.T.

    1984-01-01

    The mechanism by which ionizing radiation induces genetic damage in haploid and diploid conidia of Aspergillus nidulans was investigated. Although the linear dose-response curves obtained following low LET irradiation implied a 'single-hit' action of radiation, high LET radiations were much more efficient than low LET radiations, which suggests the involvement of a multiple target system. It was found that the RBE values for non-disjunction and mitotic crossing-over were very different. Unlike mitotic crossing-over, the RBE values for non-disjunction were much greater than for cell killing. This suggests that non-disjunction is a particularly sensitive genetical endpoint that is brought about by damage to a small, probably non-DNA target. Radiosensitisers were used to study whether radiation acts at the level of the DNA or some other cellular component. The sensitisation to electrons and/or X-rays by oxygen, and two nitroimidazoles (metronidazole and misonidazole) was examined for radiation induced non-disjunction, mitotic crossing-over, gene conversion, point mutation and cell killing. It was found that these compounds sensitised the cells considerably more to genetic damage than to cell killing. (author)

  12. Radiation damage of structural materials

    International Nuclear Information System (INIS)

    Koutsky, J.; Kocik, J.

    1994-01-01

    Maintaining the integrity of nuclear power plants (NPP) is critical in the prevention or control of severe accidents. This monograph deals with both basic groups of structural materials used in the design of light-water nuclear reactors, making the primary safety barriers of NPPs. Emphasis is placed on materials used in VVER-type nuclear reactors: Cr-Mo-V and Cr-Ni-Mo-V steel for reactor pressure vessels (RPV) and Zr-Nb alloys for fuel element cladding. The book is divided into seven main chapters, with the exception of the opening one and the chapter providing phenomenological background for the subject of radiation damage. Chapters 3-6 are devoted to RPV steels and chapters 7-9 to zirconium alloys, analyzing their radiation damage structure, changes of mechanical properties due to neutron irradiation as well as factors influencing the degree of their performance degradation. The recovery of damaged materials is also discussed. Considerable attention is paid to a comparison of VVER-type and western-type light-water materials

  13. Radiation damage of structural materials

    CERN Document Server

    Koutsky, Jaroslav

    1994-01-01

    Maintaining the integrity of nuclear power plants is critical in the prevention or control of severe accidents. This monograph deals with both basic groups of structural materials used in the design of light-water nuclear reactors, making the primary safety barriers of NPPs. Emphasis is placed on materials used in VVER-type nuclear reactors: Cr-Mo-V and Cr-Ni-Mo-V steel for RPV and Zr-Nb alloys for fuel element cladding. The book is divided into 7 main chapters, with the exception of the opening one and the chapter providing a phenomenological background for the subject of radiation damage. Ch

  14. Damages by radiation in glasses

    International Nuclear Information System (INIS)

    Olguin, F.; Gutierrez, C.; Cisniega, G.; Flores, J.H.; Golzarri, J.I.; Espinoza, G.

    1997-01-01

    As a part of the works carried out to characterize the electrons beam from the Pelletron accelerator of the Mexican Nuclear Center aluminium-silicate glass samples were irradiated. The purpose of these irradiations is to cause alterations in the amorphous microstructure of the material by means of the creation of color centers. The population density of these defects, consequence to the irradiation, is function of the exposure time which varied from 1 to 30 minutes, with an electronic beam energy of 400 keV, doing the irradiations at free atmosphere. the obtained spectra are correlated by damage which the radiation produced. (Author)

  15. Health effects of radiation damage

    International Nuclear Information System (INIS)

    Gasimova, K; Azizova, F; Mehdieva, K.

    2012-01-01

    Full text : A summary of the nature of radiactive contamination would be incomplete without some mention of the human health effects relatied to radioactivity and radioactive materials. Several excellent reviews at the variety of levels of detail have been written and should be consulted by the reader. Internal exposures of alpha and beta particles are important for ingested and inhaled radionuclides. Dosimetry models are used to estimate the dose from internally deposited radioactive particles. As mentioned above weighting parameters that take into account the radiation type, the biological half-life and the tissue or organ at risk are used to convert the physically absorbed dose in units of gray (or red) to the biologically significant committed equivalent dose and effective dose, measured in units of Sv (or rem). There is considerable controversy over the shape of the dose-response curve at the chronic low dose levels important for enviromental contamination. Proposed models include linear models, non-linear models and threshold models. Because risks at low dose must be extrapolated from available date at high doses, the shape of the dose-response curve has important implications for the environmental regulations used to protect the general public. The health effect of radiation damage depends on a combination of events of on the cellular, tissue and systemic levels. These lead to mutations and cellular of the irradiated parent cell. The dose level at which significant damage occurs depends on the cell type. Cells that reproduce rapidily, such as those found in bone marrow or the gastrointestinal tract, will be more sensitive to radiation than those that are longer lived, such as striated muscle or nerve cells. The effects of high radiation doses on an organ depends on the various cell types it contains

  16. Radiation damage to DNA constituents

    International Nuclear Information System (INIS)

    Bergene, R.

    1977-01-01

    The molecular changes of the DNA molecule, in various systems exposed to inoizing radiation, have been the subject of a great number of studies. In the present work electron spin resonance spectroscopy (ESR) has been applied to irradiated crystalline systems, in particular single crystals of DNA subunits and their derivatives. The main conclusions about the molecular damage are based on this technique in combination with molecular orbital calculations. It should be emphasized that the ESR technique is restricted to damage containing unpaired electrons. These unstable intermediates called free radicals seem, however, to be involved in all molecular models describing the action of radiation on DNA. One of the premises for a detailed theory of the radiation induced reactions at the physico-chemical level seems to involve exact knowledge of the induced free radicals as well as the modes of their formation and fate. For DNA, as such, it is hardly possible to arrive at such a level of knowledge since the molecular complexity prevents selective studies of the many different radiation induced products. One possible approach is to study the free radicals formed in the constituents of DNA. In the present work three lines of approach should be mentioned. The first is based on the observation that radical formation in general causes only minor structural alterations to the molecule in question. The use of isotopes with different spin and magnetic moment (in particular deuterium) may also serve a source of information. Deuteration leads to a number of protons, mainly NH - and OH, becoming substituted, and if any of these are involved in interactions with unpaired protons the resonance pattern is influeneed. The third source of information is molecular orbital calculation. The electron spin density distribution is a function in the three dimensional space based on the system's electronic wave functions. This constitutes the basis for the idea that ESR data can be correlated with

  17. Study of radiation damage to the CMS Hadronic Endcap Calorimeter and investigation into new physics using multi-boson measurements

    International Nuclear Information System (INIS)

    Belloni, Alberto

    2016-01-01

    This document is the final report for the U.S. D.O.E. Grant No. DE-SC0014088, which covers the period from May 15, 2015 to March 31, 2016. The funded research covered the study of multi-boson final states, culminated in the measurement of the W"+"-γγ and, for the first time at an hadronic collider, of the Z?? production cross sections. These processes, among the rarest multi-boson final states measurable by LHC experiments, allow us to investigate the possibility of new physics in a model-independent way, by looking for anomalies in the standard model couplings among electroweak bosons. In particular, these 3-boson final states access quartic gauge couplings; the W"+"-γγ analysis performed as a part of this proposal sets limits on anomalies in the WWγγ quartic gauge coupling. The award also covered R&D activities to define a radiation-tolerant material to be used in the incoming upgrade of the CMS hadronic endcap calorimeter. In particular, the usage of a liquid-scintillator-based detector was investigated. The research work performed in this direction has been collected in a paper recently submitted for publication in the Journal of Instrumentation (JINST).

  18. Study of radiation damage to the CMS Hadronic Endcap Calorimeter and investigation into new physics using multi-boson measurements

    Energy Technology Data Exchange (ETDEWEB)

    Belloni, Alberto [Univ. of Maryland, College Park, MD (United States)

    2016-03-31

    This document is the final report for the U.S. D.O.E. Grant No. DE-SC0014088, which covers the period from May 15, 2015 to March 31, 2016. The funded research covered the study of multi-boson final states, culminated in the measurement of the W±γγ and, for the first time at an hadronic collider, of the Zγγ production cross sections. These processes, among the rarest multi-boson final states measurable by LHC experiments, allow us to investigate the possibility of new physics in a model-independent way, by looking for anomalies in the standard model couplings among electroweak bosons. In particular, these 3-boson final states access quartic gauge couplings; the W±γγ analysis performed as a part of this proposal sets limits on anomalies in the WWγγ quartic gauge coupling. The award also covered R&D activities to define a radiation-tolerant material to be used in the incoming upgrade of the CMS hadronic endcap calorimeter. In particular, the usage of a liquid-scintillator-based detector was investigated. The research work performed in this direction has been collected in a paper recently submitted for publication in the Journal of Instrumentation (JINST).

  19. Computer simulations of radiation damage in protein crystals

    International Nuclear Information System (INIS)

    Zehnder, M.

    2007-03-01

    The achievable resolution and the quality of the dataset of an intensity data collection for structure analysis of protein crystals with X-rays is limited among other factors by radiation damage. The aim of this work is to obtain a better quantitative understanding of the radiation damage process in proteins. Since radiation damage is unavoidable it was intended to look for the optimum ratio between elastically scattered intensity and radiation damage. Using a Monte Carlo algorithm physical processes after an inelastic photon interaction are studied. The main radiation damage consists of ionizations of the atoms through the electron cascade following any inelastic photon interaction. Results of the method introduced in this investigation and results of an earlier theoretical studies of the influence of Auger-electron transport in diamond are in a good agreement. The dependence of the radiation damage as a function of the energy of the incident photon was studied by computer-aided simulations. The optimum energy range for diffraction experiments on the protein myoglobin is 10-40 keV. Studies of radiation damage as a function of crystal volume and shape revealed that very small plate or rod shaped crystals suffer less damage than crystals formed like a cube with the same volume. Furthermore the influence of a few heavy atoms in the protein molecule on radiation damage was examined. Already two iron atoms in the unit cell of myoglobin increase radiation damage significantly. (orig.)

  20. Radiation-induced damage of membranes

    International Nuclear Information System (INIS)

    Yonei, Shuji

    1977-01-01

    An outline of membranous structure was stated, and radiation-induced damage of membranes were surveyed. By irradiation, permeability of membranes, especially passive transportation mechanism, was damaged, and glycoprotein in the surface layers of cells and the surface layer structures were changed. The intramembranous damage was induced by decrease of electrophoresis of nuclear mambranes and a quantitative change of cytochrome P450 of microsomal membranes of the liver, and peroxidation of membranous lipid and SH substitute damage of membranous protein were mentioned as the mechanism of membranous damage. Recovery of membranous damage depends on radiation dose and temperature, and membranous damage participates largely in proliferation death. (tsunoda, M.)

  1. Radiation damage in nanostructured metallic films

    Science.gov (United States)

    Yu, Kaiyuan

    High energy neutron and charged particle radiation cause microstructural and mechanical degradation in structural metals and alloys, such as phase segregation, void swelling, embrittlement and creep. Radiation induced damages typically limit nuclear materials to a lifetime of about 40 years. Next generation nuclear reactors require materials that can sustain over 60 - 80 years. Therefore it is of great significance to explore new materials with better radiation resistance, to design metals with favorable microstructures and to investigate their response to radiation. The goals of this thesis are to study the radiation responses of several nanostructured metallic thin film systems, including Ag/Ni multilayers, nanotwinned Ag and nanocrystalline Fe. Such systems obtain high volume fraction of boundaries, which are considered sinks to radiation induced defects. From the viewpoint of nanomechanics, it is of interest to investigate the plastic deformation mechanisms of nanostructured films, which typically show strong size dependence. By controlling the feature size (layer thickness, twin spacing and grain size), it is applicable to picture a deformation mechanism map which also provides prerequisite information for subsequent radiation hardening study. And from the viewpoint of radiation effects, it is of interest to explore the fundamentals of radiation response, to examine the microstructural and mechanical variations of irradiated nanometals and to enrich the design database. More importantly, with the assistance of in situ techniques, it is appealing to examine the defect generation, evolution, annihilation, absorption and interaction with internal interfaces (layer interfaces, twin boundaries and grain boundaries). Moreover, well-designed nanostructures can also verify the speculation that radiation induced defect density and hardening show clear size dependence. The focus of this thesis lies in the radiation response of Ag/Ni multilayers and nanotwinned Ag

  2. Radiation damages in solids and tissues

    International Nuclear Information System (INIS)

    Cevc, P.; Kogovsek, F.; Kanduser, A.; Peternelj, M.; Skaleric, U.; Funduk, N.

    1977-01-01

    In submitted research work we have studied radiation damages in ferroelectric crystals and application of ferroelectric crystals. Studying the radiation damages we have introduced new technique of EPR measurements under high hydrostatic pressure, that will enable us to obtain additional data on crystal lattice dynamics. A change of piroelectric coefficient with high radiation doses in dopped TGS has been measured also

  3. Radiation damage at LHCb, results and expectations

    CERN Multimedia

    Faerber, Christian

    2011-01-01

    The LHCb Detector is a single-arm spectrometer at the LHC designed to detect new physics through measuring CP violation and rare decays of heavy flavor mesons. The detector consists of vertex detector, tracking system, dipole magnet, 2 RICH detectors, em. calorimeter, hadron calorimeter, muon detector which all use different technologies and suffer differently from radiation damage. These radiation damage results and the investigation methods will be shown. The delivered luminosity till July 2011 was about 450 pb−1. The Vertex detector receives the highest particle flux at LHCb. The currents drawn by the silicon sensors are, as expected, increasing proportional to the integrated luminosity. The highest irradiaton regions of the n-bulk silicon sensors are observed to have recently undergone space charge sign inversion. The Silicon Trackers show increasing leakage currents comparable with earlier predictions. The electromagentic calorimeter and hadron calorimeter suffer under percent-level signal decrease whi...

  4. Metamict state radiation damage in crystalline materials

    International Nuclear Information System (INIS)

    Haaker, R.F.; Ewing, R.C.

    1979-01-01

    Metamict minerals provide an excellent basis for the evaluation of long-term radiation damage effects, particularly such changes in physical and chemical properties as microfracturing, hydrothermal alteration, and solubility. This paper summarizes pertinent literature on metamictization and proposes experiments that are critical to the elucidation of structural controls on radiation damage in crystalline phases

  5. [Mechanisms of electromagnetic radiation damaging male reproduction].

    Science.gov (United States)

    Xue, Lei; Chen, Hao-Yu; Wang, Shui-Ming

    2012-08-01

    More and more evidence from over 50 years of researches on the effects of electromagnetic radiation on male reproduction show that a certain dose of electromagnetic radiation obviously damages male reproduction, particularly the structure and function of spermatogenic cells. The mechanisms of the injury may be associated with energy dysmetabolism, lipid peroxidation, abnormal expressions of apoptosis-related genes and proteins, and DNA damage.

  6. Repair of radiation damage in mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Setlow, R.B.

    1981-01-01

    The responses, such as survival, mutation, and carcinogenesis, of mammalian cells and tissues to radiation are dependent not only on the magnitude of the damage to macromolecular structures - DNA, RNA, protein, and membranes - but on the rates of macromolecular syntheses of cells relative to the half-lives of the damages. Cells possess a number of mechanisms for repairing damage to DNA. If the repair systems are rapid and error free, cells can tolerate much larger doses than if repair is slow or error prone. It is important to understand the effects of radiation and the repair of radiation damage because there exist reasonable amounts of epidemiological data that permits the construction of dose-response curves for humans. The shapes of such curves or the magnitude of the response will depend on repair. Radiation damage is emphasized because: (a) radiation dosimetry, with all its uncertainties for populations, is excellent compared to chemical dosimetry; (b) a number of cancer-prone diseases are known in which there are defects in DNA repair and radiation results in more chromosomal damage in cells from such individuals than in cells from normal individuals; (c) in some cases, specific radiation products in DNA have been correlated with biological effects, and (d) many chemical effects seem to mimic radiation effects. A further reason for emphasizing damage to DNA is the wealth of experimental evidence indicating that damages to DNA can be initiating events in carcinogenesis.

  7. Nature of radiation damage in ceramics

    International Nuclear Information System (INIS)

    Bunch, J.M.

    1976-01-01

    Efforts to determine the equivalence between different sources of radiation damage in ceramics are reviewed. The ways in which ceramics differ from metals are examined and proposed mechanisms for creation and stabilization of defects in insulators are outlined. Work on radiation damage in crystalline oxides is summarized and suggestions for further research are offered

  8. Repair of radiation damage in mammalian cells

    International Nuclear Information System (INIS)

    Setlow, R.B.

    1981-01-01

    The responses, such as survival, mutation, and carcinogenesis, of mammalian cells and tissues to radiation are dependent not only on the magnitude of the damage to macromolecular structures - DNA, RNA, protein, and membranes - but on the rates of macromolecular syntheses of cells relative to the half-lives of the damages. Cells possess a number of mechanisms for repairing damage to DNA. If the repair systems are rapid and error free, cells can tolerate much larger doses than if repair is slow or error prone. It is important to understand the effects of radiation and the repair of radiation damage because there exist reasonable amounts of epidemiological data that permits the construction of dose-response curves for humans. The shapes of such curves or the magnitude of the response will depend on repair. Radiation damage is emphasized because: (a) radiation dosimetry, with all its uncertainties for populations, is excellent compared to chemical dosimetry; (b) a number of cancer-prone diseases are known in which there are defects in DNA repair and radiation results in more chromosomal damage in cells from such individuals than in cells from normal individuals; (c) in some cases, specific radiation products in DNA have been correlated with biological effects, and (d) many chemical effects seem to mimic radiation effects. A further reason for emphasizing damage to DNA is the wealth of experimental evidence indicating that damages to DNA can be initiating events in carcinogenesis

  9. Radiation damage in semiconductor detectors

    International Nuclear Information System (INIS)

    Kraner, H.W.

    1981-12-01

    A survey is presented of the important damage-producing interactions in semiconductor detectors and estimates of defect numbers are made for MeV protons, neutrons and electrons. Damage effects of fast neutrons in germanium gamma ray spectrometers are given in some detail. General effects in silicon detectors are discussed and damage constants and their relationship to leakage current is introduced

  10. Ion - biomolecule interactions and radiation damage

    International Nuclear Information System (INIS)

    Schlathoelter, T.

    2004-01-01

    Full text: The biological effects of ionizing radiation in living cells are not a mere result of the direct impact of high energy quanta of radiation. Secondary particles such as low energy electrons, radicals and (multiply charged) ions are formed within the track. The interaction of these secondary particles with biologically relevant molecules is responsible for a large fraction of biological radiation damage to a cell, as well. Singly and multiply charged ions can be of importance as both, primary and secondary particles, and are known to cause severe biological damage. For instance, in heavy ion therapy and proton therapy the pronounced Bragg peak of fast (typically a few 100 MeV/u) ions in biological tissue is utilized. The Bragg peak is located at a depth, where the ions (mostly C q+ or protons) are slowed down to about 100 keV/u and have their maximum linear energy transfer (LET) to the medium. This depth is reasonably well defined and depends on the initial ion kinetic energy. Since the ions are rapidly stopped in this energy range, penetration beyond the Bragg peak is weak and it is thus possible to 'scan' the Bragg peak through a malignant tumour without excessive damage of the surrounding tissue by mere variation of the ion kinetic energy (i.e. the penetration depth). Severe biological damage is almost only possible, when the track of a primary quantum of ionizing radiation crosses the nucleus of a cell. Particularly the induction of double strand breaks of DNA or clustered DNA lesions is potentially lethal or mutagenic. A primary particle interacting with individual molecules within this environment leads to molecular excitation, ionization and fragmentation. In the process, the primary particle looses energy and slow secondary electrons and ions are formed, which might induce further damage. For a deep understanding of biological radiation damage on the level of individual molecules it is thus important to quantify excitation, ionization and

  11. Radiation damage in optical fibers

    International Nuclear Information System (INIS)

    Lyons, P.B.; Looney, L.D.; Ogle, J.W.

    1983-01-01

    Optical fibers provide important advantages over coaxial cables for many data transmission applications. Some of these applications require that the fibers transmit data during a radiation pulse. Other applications utilize the fiber as a radiation-to-light transducer. In either case, radiation-induced luminescence and absorption must be understood. Most studies of radiation effects in fibers have emphasized time scales of interest in telecommunication systems, from the msec to hour range. Few studies have concentrated on response at times below 1 + s. At Los Alamos, both laboratory electron accelerators and nuclear tests have been used as radiation sources to probe this early time region. The use of a fiber (or any optical medium) as a Cerenkov radiation-to-light transducer is discussed. Since the radiation induces attenuation in the medium, the light output is not proportional to the radiation input. The nonlinearity introduced by this attenuation is calculated

  12. Thermal annealing of natural, radiation-damaged pyrochlore

    Energy Technology Data Exchange (ETDEWEB)

    Zietlow, Peter; Beirau, Tobias; Mihailova, Boriana; Groat, Lee A.; Chudy, Thomas; Shelyug, Anna; Navrotsky, Alexandra; Ewing, Rodney C.; Schlüter, Jochen; Škoda, Radek; Bismayer, Ulrich

    2017-01-01

    Abstract

    Radiation damage in minerals is caused by the α-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400–1000 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia [6.4 wt% Th, 23.1·10

  13. Radiation damage for the spallation target of ADS

    International Nuclear Information System (INIS)

    Fan Sheng; Ye Yanlin; Xu Chuncheng; Chen Tao; Sobolevsky, N.M.

    2000-01-01

    By using SHIELD codes system, the authors investigate the radiation damage, such as radiation damage cross section, displacement atom cross section and the rate of displacement atom, gas production cross section, the rate of gas production and the ratio, R, of the helium and displacement production rates in target, container window and spallation neutron source materials as W and Pb induced from intermediate energy proton and neutron incident. And the study of radiation damage in the thick Pb target with long 60 cm, radius 20 cm is presented

  14. Radiation damage in barium fluoride detector materials

    International Nuclear Information System (INIS)

    Levey, P.W.; Kierstead, J.A.; Woody, C.L.

    1988-01-01

    To develop radiation hard detectors, particularly for high energy physics studies, radiation damage is being studied in BaF 2 , both undoped and doped with La, Ce, Nd, Eu, Gd and Tm. Some dopants reduce radiation damage. In La doped BaF 2 they reduce the unwanted long lifetime luminescence which interferes with the short-lived fluorescence used to detect particles. Radiation induced coloring is being studied with facilities for making optical measurements before, during and after irradiation with 60 C0 gamma rays. Doses of 10 6 rad, or less, create only ionization induced charge transfer effects since lattice atom displacement damage is negligible at these doses. All crystals studied exhibit color center formation, between approximately 200 and 800 nm, during irradiation and color center decay after irradiation. Thus only measurements made during irradiation show the total absorption present in a radiation field. Both undoped and La doped BaF 2 develop damage at minimum detectable levels in the UV---which is important for particle detectors. For particle detector applications these studies must be extended to high dose irradiations with particles energetic enough to cause lattice atom displacement damage. In principle, the reduction in damage provided by dopants could apply to other applications requiring radiation damage resistant materials

  15. Radiation damage to nucleoprotein complexes in macromolecular crystallography

    International Nuclear Information System (INIS)

    Bury, Charles; Garman, Elspeth F.; Ginn, Helen Mary; Ravelli, Raimond B. G.; Carmichael, Ian; Kneale, Geoff; McGeehan, John E.

    2015-01-01

    Quantitative X-ray induced radiation damage studies employing a model protein–DNA complex revealed a striking partition of damage sites. The DNA component was observed to be far more resistant to specific damage compared with the protein. Significant progress has been made in macromolecular crystallography over recent years in both the understanding and mitigation of X-ray induced radiation damage when collecting diffraction data from crystalline proteins. In contrast, despite the large field that is productively engaged in the study of radiation chemistry of nucleic acids, particularly of DNA, there are currently very few X-ray crystallographic studies on radiation damage mechanisms in nucleic acids. Quantitative comparison of damage to protein and DNA crystals separately is challenging, but many of the issues are circumvented by studying pre-formed biological nucleoprotein complexes where direct comparison of each component can be made under the same controlled conditions. Here a model protein–DNA complex C.Esp1396I is employed to investigate specific damage mechanisms for protein and DNA in a biologically relevant complex over a large dose range (2.07–44.63 MGy). In order to allow a quantitative analysis of radiation damage sites from a complex series of macromolecular diffraction data, a computational method has been developed that is generally applicable to the field. Typical specific damage was observed for both the protein on particular amino acids and for the DNA on, for example, the cleavage of base-sugar N 1 —C and sugar-phosphate C—O bonds. Strikingly the DNA component was determined to be far more resistant to specific damage than the protein for the investigated dose range. At low doses the protein was observed to be susceptible to radiation damage while the DNA was far more resistant, damage only being observed at significantly higher doses

  16. Investigating α-particle radiation damage in phyllosilicates using synchrotron microfocus-XRD/XAS: implications for geological disposal of nuclear waste

    Science.gov (United States)

    Bower, W. R.; Pearce, C. I.; Pimblott, S. M.; Haigh, S. J.; Mosselmans, J. F. W.; Pattrick, R. A. D.

    2014-12-01

    The response of mineral phases to the radiation fields that will be experienced in a geological disposal facility (GDF) for nuclear waste is poorly understood. Phyllosilicates are critical phases in a GDF with bentonite clay as the backfill of choice surrounding high level wastes in the engineered barrier, and clays and micas forming the most important reactive component of potential host rocks. It is essential that we understand changes in mineral properties and behaviour as a result of damage from both α and γ radiation over long timescales. Radiation damage has been demonstrated to affect the physical integrity and oxidation state1 of minerals which will also influence their ability to react with radionuclides. Using the University of Manchester's newly commissioned particle accelerator at the Dalton Cumbrian Facility, UK, model phyllosilicate minerals (e.g. biotite, chlorite) were irradiated with high energy (5MeV) alpha particles at controlled dose rates. This has been compared alongside radiation damage found in naturally formed 'radiohalos' - spherical areas of discolouration in minerals surrounding radioactive inclusions, resulting from alpha particle penetration, providing a natural analogue to study lattice damage under long term bombardment1,2. Both natural and artificially irradiated samples have been analysed using microfocus X-ray absorption spectroscopy and high resolution X-ray diffraction mapping on Beamline I18 at Diamond Light Source; samples were probed for redox changes and long/short range disorder. This was combined with lattice scale imaging of damage using HR-TEM (TitanTM Transmission Electron Microscope). The results show aberrations in lattice parameters as a result of irradiation, with multiple damage-induced 'domains' surrounded by amorphous regions. In the naturally damaged samples, neo-formed phyllosilicate phases are shown to be breakdown products of highly damaged regions. A clear reduction of the Fe(III) component has been

  17. Radiation damage analysis by positron annihilation spectroscopy

    International Nuclear Information System (INIS)

    Siegel, R.W.

    1979-01-01

    The application of positron annihilation spectroscopy (PAS) to the characterization and study of defects in metals produced by radiation damage is discussed. The physical basis for the positron annihilation techniques (lifetime, Doppler broadening, angular correlation) is introduced and the techniques briefly described. Some examples of the application of PAS to radiation damage analysis are presented with a view toward elucidating the particular advantages of PAS over more traditional defect characterization techniques

  18. DNA Damage Signals and Space Radiation Risk

    Science.gov (United States)

    Cucinotta, Francis A.

    2011-01-01

    Space radiation is comprised of high-energy and charge (HZE) nuclei and protons. The initial DNA damage from HZE nuclei is qualitatively different from X-rays or gamma rays due to the clustering of damage sites which increases their complexity. Clustering of DNA damage occurs on several scales. First there is clustering of single strand breaks (SSB), double strand breaks (DSB), and base damage within a few to several hundred base pairs (bp). A second form of damage clustering occurs on the scale of a few kbp where several DSB?s may be induced by single HZE nuclei. These forms of damage clusters do not occur at low to moderate doses of X-rays or gamma rays thus presenting new challenges to DNA repair systems. We review current knowledge of differences that occur in DNA repair pathways for different types of radiation and possible relationships to mutations, chromosomal aberrations and cancer risks.

  19. Investigation of Combined Action of Food Supplement's and Ionizing Radiation on the Cytogenetic Damage Induction and Ehrlich Ascite Carcinoma Growth on Mice in Vivo

    Science.gov (United States)

    Sorokina, Svetlana; Zaichkina, Svetlana; Dyukina, Alsu; Rozanova, Olga; Balakin, Vladimir; Peleshko, Vladimir; Romanchenko, Sergey; Smirnova, Helena; Aptikaeva, Gella; Shemyakov, Alexander

    In recent ten years one of the major problems of modern radiobiology is the study of radiation protective mechanisms with the help of different substances as well as activation of internal resources of the organism. Internal resources mean such phenomena as hormesis and adaptive response which represent cell or body reaction on low doses of inducing factors and predetermine their further high dose effect resistance. At present special interest is attracted by studies of biological effects of low-dose-rate high-LET radiation because of searching for new types of radiation for more effective cancer therapy and searching for new methods of radiation protection. Since natural biologically active substances have low toxicity and are capable of affecting physiological processes taking place in human’s organism and increasing organism’s natural defense system, the interest to protective means of vegetal origin and search of special food supplements intensifies every year. The purpose of this study is to investigate the combined influence of food supplement, low dose rate high-LET radiation simulating high-altitude flight conditions and X-ray radiations on radiosensitivity, induction of radiation adaptive response (RAR) and growth of Ehrlich ascite carcinoma as well. Experiments were performed with males of SHK mice at the age of two months. The animals were being irradiated with low-dose-rate high-LET radiation with the dose of 11,6 cGy (0,5 cGy/day) behind the concrete shield of the 70 GeV protons accelerator (Protvino). The X-ray irradiation was carried out on the RTH device with a voltage of 200 kV (1 Gy/min; Pushchino). The diet composition included products containing big amount of biologically active substances, such as: soybeam meat, buckwheat, lettuce leaves and drug of cod-liver oil. Four groups of mice were fed with selected products mentioned above during the whole irradiation period of 22 days. The control groups received the same food without irradiation

  20. Radiation damage analysis by positron annihilation spectroscopy

    International Nuclear Information System (INIS)

    Siegel, R.W.

    1982-01-01

    Positron annihilation spectroscopy (PAS) has in recent years become a valuable new tool for investigating defects in metals. The ability of the positron to localize in a trapped state at various defect sites, in which the positron annihilates with unique characteristics, has enabled the positron to be used as a localized probe of these defect sites. Several reviews of the application of PAS to the study of defects in metals have been published, as have more general treatises on the applications of positron annihilation to the study of solids. PAS has made, and has considerably greater potential for, a significant contribution to radiation damage analysis in two areas of importance: (1) the determination of atomic-defect properties, a knowledge of which is necessary for the modeling required to couple the results of model experiments using electron and ion irradiation with the expected irradiation conditions of reactor systems, and (2) the monitoring and characterization of irradiation-induced microstructure development. A unique aspect of PAS for radiation damage analysis is the defect specificity of the annihilation characteristics of a trapped positron. In addition to its value as an independent analytical tool, PAS can be a useful complement to more traditional techniques for defect studies

  1. Hydration-annealing of chemical radiation damage in calcium nitrate

    International Nuclear Information System (INIS)

    Nair, S.M.K.; James, C.

    1984-01-01

    The effect of hydration on the annealing of chemical radiation damage in anhydrous calcium nitrate has been investigated. Rehydration of the anhydrous irradiated nitrate induces direct recovery of the damage. The rehydrated salt is susceptible to thermal annealing but the extent of annealing is small compared to that in the anhydrous salt. The direct recovery of damage on rehydration is due to enhanced lattice mobility. The recovery process is unimolecular. (author)

  2. Radiation damage of metal uranium

    International Nuclear Information System (INIS)

    Mihajlovic, A.

    1965-01-01

    This report is concerned with the role of dispersion second phase in uranium and burnup rate. The role of dispersion phases in radiation stability of metal uranium was studies by three methods: variation of electric conductivity dependent on the neutron flux and temperature of pure uranium for different states of dispersion second phase; influence of dispersion phase on the radiation creep; transmission electron microscopy of fresh and irradiated uranium

  3. Molecular mechanisms in radiation damage to DNA

    International Nuclear Information System (INIS)

    Osman, R.

    1991-01-01

    The objectives of this work are to elucidate the molecular mechanisms that are responsible for radiation-induced DNA damage. The overall goal is to understand the relationship between the chemical and structural changes produced by ionizing radiation in DNA and the resulting impairment of biological function expressed as carcinogenesis or cell death. The studies are based on theoretical explorations of possible mechanisms that link initial radiation damage in the form of base and sugar damage to conformational changes in DNA. These mechanistic explorations should lead to the formulation of testable hypothesis regarding the processes of impairment of regulation of gene expression, alternation in DNA repair, and damage to DNA structure involved in cell death or cancer

  4. Radiation Damage in Electronic Memory Devices

    OpenAIRE

    Fetahović, Irfan; Pejović, Milić; Vujisić, Miloš

    2013-01-01

    This paper investigates the behavior of semiconductor memories exposed to radiation in order to establish their applicability in a radiation environment. The experimental procedure has been used to test radiation hardness of commercial semiconductor memories. Different types of memory chips have been exposed to indirect ionizing radiation by changing radiation dose intensity. The effect of direct ionizing radiation on semiconductor memory behavior has been analyzed by using Monte Carlo simula...

  5. New concepts for radiation damage

    International Nuclear Information System (INIS)

    Michelin, Severino C.

    2004-01-01

    Evidence accumulated over the past two decades has indicated that exposure of cell populations to ionizing radiation results in significant biological effects occurring in both the irradiated and non-irradiated cells in the population. This phenomenon, termed the 'bystander response', has been shown to occur both in vitro and in vivo. Experiments have indicated that genetic alterations, changes in gene expression and lethality occur in bystander cells that neighbour directly irradiated cells. Furthermore, cells recipient of growth medium harvested from irradiated cultures exhibit responses similar to those of the irradiated cells. Several mechanisms involving secreted soluble factors, gap-junction intercellular communication and oxidative metabolism have been proposed to regulate the radiation-induced bystander effect. In this lecture, our current knowledge of this phenomenon and its potential impact both on the estimation of risks of exposure to low doses/low fluences of ionizing radiation and on radiotherapy is discussed. (author)

  6. Analysis of radiation damaged nanocrystals

    International Nuclear Information System (INIS)

    Sitek, J.; Dekan, J.; Sedlackova, K.; Sagatova, A.

    2014-01-01

    Ribbon-shaped specimens of the master alloy were prepared by planar flow casting. The ribbons with nominal composition of (Fe_1_-_xN_x)_8_1Nb_7B_1_2 (x = 0, 0.25, 0.5, 0.75) were about 25 μm thick and 10 mm wide. To achieve nanocrystalline state, the amorphous ribbons were annealed in vacuum at the temperature of 550 grad C for 1 hour. Samples were irradiated by neutrons in nuclear reactor with fluence of 10"1"6 n/cm"2 and 10"1"7 n/cm"2. and by electrons in linear accelerator with dose 1 MGy at the Slovak Medical University. Moessbauer spectra were collected in transmission geometry by a conventional constant-acceleration spectrometer with a "5"7Co(Rh) source. All spectra were measured at room temperature and evaluated by the CONFIT program, which allows simultaneous treatment of crystalline and residual amorphous phase by means of individual lines and distribution of hyperfine components. After summarizing all obtained results, the fluence 10"1"6 n/cm"2 is still not sufficiently high significantly damage amorphous and crystalline structure. This fluence more or less modify the structure than damage. After fluence 10"17"n/cm"2 we observed beginning of the. structural damage. Our results show, that high electron dose also modify the structure of nanocrystaline alloys. In further study of this alloy it would be necessary to find the limit of electron dose under that the alloy is resistant against electron's damage. From point of view Moessbauer spectroscopy the most sensitive parameter is direction of net magnetic moment. (authors)

  7. Protection of DNA damage by radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Ho; Kim, In Gyu; Lee, Kang Suk; Kim, Kug Chan; Oh, Tae Jung

    1998-12-01

    The SOS response of Escherichia coli is positively regulated by RecA. To examine the effects of polyamines on The SOS response of E. Coli, we investigated the expression of recA gene in polyamine-deficient mutant and wild type carrying recA'::lacZ fusion gene. As a result, recA expression by mitomycin C is higher in wild type than that of polyamine-deficient mutant, but recA expression by UV radiation is higher in wild type than of mutant. We also found that exogenous polyamines restored the recA expression in the polyamine-deficient mutant to the wild type level. These results proposed that polyamines play an important role in mechanism of intracellular DNA protection by DNA damaging agents.

  8. Protection of DNA damage by radiation exposure

    International Nuclear Information System (INIS)

    Lee, Jeong Ho; Kim, In Gyu; Lee, Kang Suk; Kim, Kug Chan; Oh, Tae Jung

    1998-12-01

    The SOS response of Escherichia coli is positively regulated by RecA. To examine the effects of polyamines on The SOS response of E. Coli, we investigated the expression of recA gene in polyamine-deficient mutant and wild type carrying recA'::lacZ fusion gene. As a result, recA expression by mitomycin C is higher in wild type than that of polyamine-deficient mutant, but recA expression by UV radiation is higher in wild type than of mutant. We also found that exogenous polyamines restored the recA expression in the polyamine-deficient mutant to the wild type level. These results proposed that polyamines play an important role in mechanism of intracellular DNA protection by DNA damaging agents

  9. Protection of DNA damage by radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Ho; Kim, In Gyu; Lee, Kang Suk; Kim, Kug Chan; Oh, Tae Jung

    1998-12-01

    The SOS response of Escherichia coli is positively regulated by RecA. To examine the effects of polyamines on The SOS response of E. Coli, we investigated the expression of recA gene in polyamine-deficient mutant and wild type carrying recA'::lacZ fusion gene. As a result, recA expression by mitomycin C is higher in wild type than that of polyamine-deficient mutant, but recA expression by UV radiation is higher in wild type than of mutant. We also found that exogenous polyamines restored the recA expression in the polyamine-deficient mutant to the wild type level. These results proposed that polyamines play an important role in mechanism of intracellular DNA protection by DNA damaging agents.

  10. Development of fusion first-wall radiation damage facilities

    International Nuclear Information System (INIS)

    McElroy, R.J.; Atkins, T.

    1986-11-01

    The report describes work performed on the development of fusion-reactor first-wall simulation facilities on the Variable Energy Cyclotron, at Harwell, United Kingdom. Two irradiation facilities have been constructed: i) a device for helium and hydrogen filling up to 1000 ppm for post-irradiation mechanical properties studies, and ii) a helium implantation and damage facility for simultaneous injection of helium and radiation damage into a specimen under stress. These facilities are now fully commissioned and are available for investigations of first-wall radiation damage and for intercorrelation of fission- and fusion -reactor materials behaviour. (U.K.)

  11. Radiation protection in radionuclide investigations

    International Nuclear Information System (INIS)

    Taylor, D.M.

    1985-01-01

    The subject is covered in sections: introduction; radiation and radioactivity; alpha particles; beta particles; neutrons; electromagnetic radiation; units of radioactivity and radiation; biological effects of radiation; the philosophy of radiation protection (ALARA principle); practical aspects of radiation protection; work with unsealed radiation sources; radionuclide studies in experimental animals; radiation safety during clinical investigations; legislative control of radiation work; radioactive waste disposal; emergency procedures; conclusion. (U.K.)

  12. Nanofoams Response to Radiation Damage

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Engang [Los Alamos National Laboratory; Serrano De Caro, Magdalena [Los Alamos National Laboratory; Wang, Yongqiang [Los Alamos National Laboratory; Nastasi, Michael [Nebraska Center for Energy Sciences Research, University of Nebraska-Lincoln, NE 68508; Zepeda-Ruiz, Luis [PLS, Lawrence Livermore National Laboratory, Livermore, CA 94551; Bringa, Eduardo M. [CONICET and Inst. Ciencias Basicas, Universidad Nacional de Cuyo, Mendoza, 5500 Argentina; Baldwin, Jon K. [Los Alamos National Laboratory; Caro, Jose A. [Los Alamos National Laboratory

    2012-07-30

    Conclusions of this presentation are: (1) np-Au foams were successfully synthesized by de-alloying process; (2) np-Au foams remain porous structure after Ne ion irradiation to 1 dpa; (3) SFTs were observed in irradiated np-Au foams with highest and intermediate flux, while no SFTs were observed with lowest flux; (4) SFTs were observed in irradiated np-Au foams at RT, whereas no SFTs were observed at LNT irradiation; (5) The diffusivity of vacancies in Au at RT is high enough so that the vacancies have enough time to agglomerate and thus collapse. As a result, SFTs were formed; (6) The high flux created much more damage/time, vacancies don't have enough time to diffuse or recombine. As a result, SFTs were formed.

  13. Radiation damage in organic materials

    International Nuclear Information System (INIS)

    Campbell, F.J.

    1981-01-01

    A surprising number of electrical components and seals are listed as being inside the containment building of a nuclear power plant. The types of radiation and their interaction with organic materials lead to a dosimetry discussion, and then a brief description of the chemical mechanisms which predominate in typical organic materials follows. Relative stability of polymer structures and the types of additives that contribute stabilization to the basic polymer matrix in formulated compounds are reviewed. However, the emphasis must now be directed toward the need to consider the total environment of nuclear plant service on the degradation of these materials if maximum reliability is to be achieved. The degradation mechanisms may be strongly affected by the dose-rate/oxidation effect. Temperature, steam and physical stress, when applied concurrently with the radiation field, can also influence the amount of absorbed dose required to produce a given change in the property being tested. Determining the degree of these influences and developing standardized test procedures to evaluate them have become the objective of several prominent research programs and international committee efforts. (author)

  14. 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)

  15. Mechanisms for radiation damage in DNA

    International Nuclear Information System (INIS)

    Sevilla, M.D.

    1985-07-01

    Radiation damage to DNA results from the direct interaction of radiation with DNA where positive ions, electrons and excited states are formed in the DNA, and the indirect effect where radical species formed in the surrounding medium by the radiation attack the DNA. The primary mechanism proposed for radiation damage, by the direct effect, is that positive and negative ions formed within the DNA strand migrate through the stacked DNA bases. The ions can then recombine, react with the DNA bases most likely to react by protonation of the anion and deprotonation or hydroxylation of the cation or transfer out of the DNA chain to the surrounding histone protein. This work as aimed at understanding the possible reactions of the DNA base ion radicals, as well as their initial distribution in the DNA strand. 31 refs

  16. Size effect in radiation damage

    International Nuclear Information System (INIS)

    Brumovsky, M.

    1979-01-01

    Radiation embrittlement of nuclear reactor pressure vessel steels is mostly measured using small standard specimens in dynamic bend tests. Their dimensions are much smaller than those of the reactor. The increase in the critical temperature (transition temperature from the brittle-to-ductile fracture) is normally measured using standard Charpy-V type specimens or small CT-type specimens. This increase is then used as the main parameter for the pressure vessel safety evaluation. The philosophy of experiments is discussed used for the nonirradiated and irradiated pressure vessel steels. A comparison of the increase in the transition temperature measured in different types of specimens using various testing methods (static and dynamic bend tests with notch or crack) is also made. The results of this comparison and another study showed a relatively good agreement. (author)

  17. Radiation Damage in Reactor Materials. Part of the Proceedings of the Symposium on Radiation Damage in Solids and Reactor Materials

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1963-08-15

    Radiation damage has presented a new design parameter for the selection of materials to be used in fuel and cladding elements, moderators, structural components and pressure vessels in nuclear reactors. The severe and novel requirements for certain optimum combinations of physical and nuclear properties have emphasized the need for a better understanding of the basic mechanisms of radiation damage. This knowledge is not only essential for progress in the field of nuclear energy, but has direct applications to space technology and semi-conductor research as well. The IAEA, as part of its programme of promoting nuclear technology, therefore convened the Symposium on Radiation Damage in Solids and Reactor Materials, 7-11 May 1962. At the invitation of, and with generous material assistance from, the Government of Italy, the Symposium was held at Venice. The Symposium was primarily concerned with the investigation of the fundamental processes of radiation that underlie the behaviour of metals, alloys and ceramics that are actually useful or potentially useful reactor materials. Two sessions were devoted to studies of irradiation effects on simple metals, as these effects are easiest to interpret. Other topics included general theory, alloys, fissionable and moderator materials and special experimental techniques for radiation damage studies. The properties influenced by irradiation which were of main concern were those of primary importance to the behaviour of solids as reactor materials (e. g. dimensional stability, phase transformation, radiation hardening, fracture, fission-gas escape from uranium and its compounds). Other properties, such as optical, electrical and magnetic properties, and effects on semiconductors, ionic and other non-metallic crystals are also of interest in that these studies can increase our knowledge of the mechanism of radiation damage in solids and provide a tool for investigation into the physics of the solid state by offering a means of

  18. Radiation Damage in Reactor Materials. Part of the Proceedings of the Symposium on Radiation Damage in Solids and Reactor Materials

    International Nuclear Information System (INIS)

    1963-01-01

    Radiation damage has presented a new design parameter for the selection of materials to be used in fuel and cladding elements, moderators, structural components and pressure vessels in nuclear reactors. The severe and novel requirements for certain optimum combinations of physical and nuclear properties have emphasized the need for a better understanding of the basic mechanisms of radiation damage. This knowledge is not only essential for progress in the field of nuclear energy, but has direct applications to space technology and semi-conductor research as well. The IAEA, as part of its programme of promoting nuclear technology, therefore convened the Symposium on Radiation Damage in Solids and Reactor Materials, 7-11 May 1962. At the invitation of, and with generous material assistance from, the Government of Italy, the Symposium was held at Venice. The Symposium was primarily concerned with the investigation of the fundamental processes of radiation that underlie the behaviour of metals, alloys and ceramics that are actually useful or potentially useful reactor materials. Two sessions were devoted to studies of irradiation effects on simple metals, as these effects are easiest to interpret. Other topics included general theory, alloys, fissionable and moderator materials and special experimental techniques for radiation damage studies. The properties influenced by irradiation which were of main concern were those of primary importance to the behaviour of solids as reactor materials (e. g. dimensional stability, phase transformation, radiation hardening, fracture, fission-gas escape from uranium and its compounds). Other properties, such as optical, electrical and magnetic properties, and effects on semiconductors, ionic and other non-metallic crystals are also of interest in that these studies can increase our knowledge of the mechanism of radiation damage in solids and provide a tool for investigation into the physics of the solid state by offering a means of

  19. Radiation Damage in CaF{sub 2}2 and BaF{sub 2} Investigated by the Channeling Technique

    Energy Technology Data Exchange (ETDEWEB)

    Hellborg, R; Skog, G

    1973-04-15

    The radiation damage in single crystals of CaF{sub 2} and BaF{sub 2} due to room temperature bombardment with 2.0 MeV helium ions has been studied by the channeling technique. Back scattering spectra for the <111> and <110> axial directions were taken after different doses of random irradiation. A slight in crease of the aligned yield with radiation dose has been found for both crystals at doses below 1017 ions/cm2. For CaF{sub 2} at a dose of about 1.4x1017 ions/cm2 a steep increase is found, after which the aligned yield saturates at a high value. Analyses of spectra measured along different aligned directions indicate that the structures of defects in CaF{sub 2} and BaF{sub 2} differ

  20. Radiation Damage in Electronic Memory Devices

    Directory of Open Access Journals (Sweden)

    Irfan Fetahović

    2013-01-01

    Full Text Available This paper investigates the behavior of semiconductor memories exposed to radiation in order to establish their applicability in a radiation environment. The experimental procedure has been used to test radiation hardness of commercial semiconductor memories. Different types of memory chips have been exposed to indirect ionizing radiation by changing radiation dose intensity. The effect of direct ionizing radiation on semiconductor memory behavior has been analyzed by using Monte Carlo simulation method. Obtained results show that gamma radiation causes decrease in threshold voltage, being proportional to the absorbed dose of radiation. Monte Carlo simulations of radiation interaction with material proved to be significant and can be a good estimation tool in probing semiconductor memory behavior in radiation environment.

  1. Radiation damage testing at the SSC [Superconducting Super Collider

    International Nuclear Information System (INIS)

    Chinowsky, W.; Thun, R.

    1990-06-01

    A Task Force on Radiation Damage Testing met at the SSC Laboratory on March 5--6, 1990. This Task Force was asked to assess the availability of appropriate facilities for radiation damage tests of SSC detector materials and components. The Task Force was also instructed to review the techniques and standards for conducting such tests. Semiconductors were considered separately from other detector materials. Radiation damage test of electronic devices generally require exposures to both ionizing radiation and neutrons, whereas non-electric components such as plastic scintillating materials, adhesives, cable insulation, and other organic polymers are adequately tested with ionizing radiation only. Test standards are discussed with respect to irradiation techniques, environmental factors, dosimetry, and mechanisms whereby various materials are damaged. It is emphasized that radiation sources should be chosen to duplicate as much as possible the expected SSC environment and that the effects from ionizing particles and from neutrons be investigated separately. Radiation damage tests at reactors must be designed with particular care complex spectra of neutrons and gamma rays are produced at such facilities. It is also essential to investigate dose-rate effects since they are known to be important in many cases. The required irradiations may last several months and are most easily carried out with dedicated radioactive sources. Environmental factors such as the presence of oxygen when testing plastic scintillators, or temperature when measuring semiconductor annealing effects, must also be taken into account. The importance of reliable dosimetry is stressed and suitable references cited. Finally, it is noted that an understanding of the mechanisms for radiation damage in semiconductor and other materials is important in planning irradiations and evaluating results

  2. State of damage of radiation facilities in great Hanshin earthquake

    International Nuclear Information System (INIS)

    1995-01-01

    The southern Hyogo Prefecture earthquake of magnitude 7.2 occurred in the early morning of January 17, 1995. The outline of the earthquake and dead and injured, the damages of buildings, life lines, roads, railways and harbors, liquefaction phenomena, the state of occurrence of fires and so on are reported. The districts where the earthquakes of magnitude 5 or stronger occurred, and the radiation facilities in those districts are shown. The state of damage of radiation facilities in past earthquakes is summarized. From January 17 to 19 after the earthquake, Science and Technology Agency gave necessary instruction to and heard the state of damage from 79 permitted facilities in the areas of magnitude 7 or 6 by telephone, and received the report that there was not the fear of radiation damage in all facilities. Also the state of damage of radiation facilities was investigated at the actual places, and the questionnaires on the state of radiation facilities and the action at the time of the earthquake were performed. The state of radiation facilities accompanying the earthquake is reported. The matters to be reflected to the countermeasures to earthquakes anew for the protection of facilities, communication system, facility checkup system and the resumption of use are pointed out. (K.I.)

  3. Radiation damage effect on avalanche photodiodes

    CERN Document Server

    Baccaro, S; Cavallari, F; Da Ponte, V; Deiters, K; Denes, P; Diemoz, M; Kirn, Th; Lintern, A L; Longo, E; Montecchi, M; Musienko, Y; Pansart, J P; Renker, D; Reucroft, S; Rosi, G; Rusack, R; Ruuska, D; Stephenson, R; Torbet, M J

    1999-01-01

    Avalanche Photodiodes have been chosen as photon sensors for the electromagnetic calorimeter of the CMS experiment at the LHC. These sensors should operate in the 4T magnetic field of the experiment. Because of the high neutron radiation in the detector extensive studies have been done by the CMS collaboration on the APD neutron radiation damage. The characteristics of these devices after irradiation have been analized, with particular attention to the quantum efficiency and the dark current. The recovery of the radiation induced dark current has been studied carefully at room temperature and at slightly lower and higher temperatures. The temperature dependence of the defects decay-time has been evaluated.

  4. The Status of Radiation Damage Experiments

    International Nuclear Information System (INIS)

    Strachan, Denis M.; Scheele, Randall D.; Icenhower, Jonathan P.; Kozelisky, Anne E.; Sell, Richard L.; Legore, Virginia L.; Schaef, Herbert T.; O'Hara, Matthew J.; Brown, Christopher F.; Buchmiller, William C.

    2001-01-01

    Experiments have been on-going for about two years to determine the effects that radiation damage have on the physical and chemical properties of candidate titanate ceramics for the immobilization of plutonium. We summarize the results of these experiments in this document

  5. Radiation damage of polymers in ultrasonic fields

    Energy Technology Data Exchange (ETDEWEB)

    Anbalagan, Poornnima

    2008-07-01

    Radiation damage has always been a topic of great interest in various fields of sciences. In this work, an attempt is made to probe into the effect of subthreshold ultrasonic waves on the radiation damage created by irradiation of deuterons in polymer samples wherein the polymer samples act as model systems. Two equal volumes of radiation damage were produced in a single polymer sample wherein a standing wave of ultrasound was introduced into one. Three polymers namely, Polycarbonate, Polymethylmethacrylate and Polyvinyl chloride were used in this work. Four independent techniques were used to analyze the irradiated samples and visualize the radiation damage. Interferometric measurements give a measure of the refractive index modulation in the irradiated sample. Polymers, being transparent, do not absorb in the visible region of the electromagnetic spectrum. UV-Vis absorption spectroscopy shows absorption peaks in the visible region in irradiated polymer samples. Ion irradiation causes coloration of polymers. The light microscope is used to measure the absorption of white light by the irradiated polymers. Positron annihilation spectroscopy is used to obtain a measure of the open volume created by irradiation in polymers. A comparison between the irradiated region and the region exposed to ultrasonic waves simultaneously with irradiation in a polymer sample shows the polymer specific influence of the ultrasonic standing wave. (orig.)

  6. Radiation damage of polymers in ultrasonic fields

    International Nuclear Information System (INIS)

    Anbalagan, Poornnima

    2008-01-01

    Radiation damage has always been a topic of great interest in various fields of sciences. In this work, an attempt is made to probe into the effect of subthreshold ultrasonic waves on the radiation damage created by irradiation of deuterons in polymer samples wherein the polymer samples act as model systems. Two equal volumes of radiation damage were produced in a single polymer sample wherein a standing wave of ultrasound was introduced into one. Three polymers namely, Polycarbonate, Polymethylmethacrylate and Polyvinyl chloride were used in this work. Four independent techniques were used to analyze the irradiated samples and visualize the radiation damage. Interferometric measurements give a measure of the refractive index modulation in the irradiated sample. Polymers, being transparent, do not absorb in the visible region of the electromagnetic spectrum. UV-Vis absorption spectroscopy shows absorption peaks in the visible region in irradiated polymer samples. Ion irradiation causes coloration of polymers. The light microscope is used to measure the absorption of white light by the irradiated polymers. Positron annihilation spectroscopy is used to obtain a measure of the open volume created by irradiation in polymers. A comparison between the irradiated region and the region exposed to ultrasonic waves simultaneously with irradiation in a polymer sample shows the polymer specific influence of the ultrasonic standing wave. (orig.)

  7. Acoustic emission sensor radiation damage threshold experiment

    International Nuclear Information System (INIS)

    Beeson, K.M.; Pepper, C.E.

    1994-01-01

    Determination of the threshold for damage to acoustic emission sensors exposed to radiation is important in their application to leak detection in radioactive waste transport and storage. Proper response to system leaks is necessary to ensure the safe operation of these systems. A radiation impaired sensor could provide ''false negative or false positive'' indication of acoustic signals from leaks within the system. Research was carried out in the Radiochemical Technology Division at Oak Ridge National Laboratory to determine the beta/gamma radiation damage threshold for acoustic emission sensor systems. The individual system consisted of an acoustic sensor mounted with a two part epoxy onto a stainless steel waveguide. The systems were placed in an irradiation fixture and exposed to a Cobalt-60 source. After each irradiation, the sensors were recalibrated by Physical Acoustics Corporation. The results were compared to the initial calibrations performed prior to irradiation and a control group, not exposed to radiation, was used to validate the results. This experiment determines the radiation damage threshold of each acoustic sensor system and verifies its life expectancy, usefulness and reliability for many applications in radioactive environments

  8. Enhancement of radiation damage in germinating wheat seeds by hyperthermia

    International Nuclear Information System (INIS)

    Guo Fangqing; Gu Ruiqi

    1994-01-01

    Enhancement of X-ray induced radiation damage in germinating wheat seeds by heat treatment (44 degree C or 41 degree C, 20 min) has been investigated. The enhancement effect of heat treatment after irradiation was more significant than that of heat treatment before irradiation at dose range of 4.3-8.6 Gy. It was observed that germinating wheat seeds were very sensitive to heat treatment within 15 min after irradiation, which indicated that the repair of radiation damage was very active and rapid in a short period after irradiation. The repair of radiation damage in interval of fractionated irradiation was severely inhibited by heat treatment. The sensitivity of seeds to heat treatment corresponded with the levels of their repair activities. The more active the repairs of the seeds are, the more sensitive to heat treatment the seeds show. It was assumed that the enhancement of radiation damage by heat treatment in germinating wheat seeds was attributed to the inhibition of radiation damage repair by heat treatment, which is similar to the results of animal experiments

  9. Radiation damage studies of nuclear structural materials

    International Nuclear Information System (INIS)

    Barat, P.

    2012-01-01

    Maximum utilization of fuel in nuclear reactors is one of the important aspects for operating them economically. The main hindrance to achieve this higher burnups of nuclear fuel for the nuclear reactors is the possibility of the failure of the metallic core components during their operation. Thus, the study of the cause of the possibility of failure of these metallic structural materials of nuclear reactors during full power operation due to radiation damage, suffered inside the reactor core, is an important field of studies bearing the basic to industrial scientific views.The variation of the microstructure of the metallic core components of the nuclear reactors due to radiation damage causes enormous variation in the structure and mechanical properties. A firm understanding of this variation of the mechanical properties with the variation of microstructure will serve as a guide for creating new, more radiation-tolerant materials. In our centre we have irradiated structural materials of Indian nuclear reactors by charged particles from accelerator to generate radiation damage and studied the some aspects of the variation of microstructure by X-ray diffraction studies. Results achieved in this regards, will be presented. (author)

  10. Damage of DNA by radiation and it's recovery, 3

    International Nuclear Information System (INIS)

    Narita, Noboru; Matsuura, Tomio; Sato, Hiroyuki.

    1974-01-01

    The damage and recovery of DNA was investigated by the incorporation of thymine derivatives (DHT, I trans, II trans, cis and glycol) into exponentially growing Tetrahymena cells. The strain employed was Tetrahymena pyriformis, Variety I, mating type IV. It is well known that these thymine derivatives are induced in vivo by radiation. The in vivo damage of DNA induced by radiation, and its recovery, were confirmed experimentally by means of gradient separation of sucrose density and by analytical ultra centrifugation (UVC). The recovery of DNA, its excision repair and its recombinational repair were compared with the recovery of Bacillus subtilis whose recovery kinetics were already known. 1) The damage of DNA was more sensitive to glycol than to II trans and cis. On the other hand, DHT is not sensitive for breaking DNA strand. 2) In its recovery damaged DNA was no more sensitive to glycol than to hhp as was true for Bacillus subtilis. (author)

  11. Radiation-damage calculations with NJOY

    International Nuclear Information System (INIS)

    MacFarlane, R.E.; Muir, D.W.; Mann, F.W.

    1983-01-01

    Atomic displacement, gas production, transmutation, and nuclear heating can all be calculated with the NJOY nuclear data processing system using evaluated data in ENDF/B format. Using NJOY helps assure consistency between damage cross sections and those used for transport, and NJOY provides convenient interface formats for linking data to application codes. Unique features of the damage calculation include a simple momentum balance treatment for radiative capture and a new model for (n, particle) reactions based on statistical model calculations. Sample results for iron and nickel are given and compared with the results of other methods

  12. Study on DNA damages induced by UV radiation

    International Nuclear Information System (INIS)

    Doan Hong Van; Dinh Ba Tuan; Tran Tuan Anh; Nguyen Thuy Ngan; Ta Bich Thuan; Vo Thi Thuong Lan; Tran Minh Quynh; Nguyen Thi Thom

    2015-01-01

    DNA damages in Escherichia coli (E. coli) exposed to UV radiation have been investigated. After 30 min of exposure to UV radiation of 5 mJ/cm"2, the growth of E. coli in LB broth medium was about only 10% in compared with non-irradiated one. This results suggested that the UV radiation caused the damages for E. coli genome resulted in reduction in its growth and survival, and those lesions can be somewhat recovered. For both solutions of plasmid DNAs and E. coli cells containing plasmid DNA, this dose also caused the breakage on single and double strands of DNA, shifted the morphology of DNA plasmid from supercoiled to circular and linear forms. The formation of pyrimidine dimers upon UV radiation significantly reduced when the DNA was irradiated in the presence of Ganoderma lucidum extract. Thus, studies on UV-induced DNA damage at molecular level are very essential to determine the UV radiation doses corresponding to the DNA damages, especially for creation and selection of useful radiation-induced mutants, as well as elucidation the protective effects of the specific compounds against UV light. (author)

  13. Radiation damage in nuclear waste materials

    International Nuclear Information System (INIS)

    Jencic, I.

    2000-01-01

    Final disposal of high-level radioactive nuclear waste is usually envisioned in some sort of ceramic material. The physical and chemical properties of host materials for nuclear waste can be altered by internal radiation and consequently their structural integrity can be jeopardized. Assessment of long-term performance of these ceramic materials is therefore vital for a safe and successful disposal. This paper presents an overview of studies on several possible candidate materials for immobilization of fission products and actinides, such as spinel (MgAl 2 O 4 ), perovskite (CaTiO 3 ), zircon (ZrSiO 4 ), and pyrochlore (Gd 2 Ti 2 O 7 and Gd 2 Zr 2 O 7 ). The basic microscopic picture of radiation damage in ceramics consists of atomic displacements and ionization. In many cases these processes result in amorphization (metaminctization) of irradiated material. The evolution of microscopic structure during irradiation leads to various macroscopic radiation effects. The connection between microscopic and macroscopic picture is in most cases at least qualitatively known and studies of radiation induced microscopic changes are therefore an essential step in the design of a reliable nuclear waste host material. The relevance of these technologically important results on our general understanding of radiation damage processes and on current research efforts in Slovenia is also addressed. (author)

  14. Nonuniform radiation damage in permanent magnet quadrupoles.

    Science.gov (United States)

    Danly, C R; Merrill, F E; Barlow, D; Mariam, F G

    2014-08-01

    We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL's pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.

  15. Nonuniform radiation damage in permanent magnet quadrupoles

    International Nuclear Information System (INIS)

    Danly, C. R.; Merrill, F. E.; Barlow, D.; Mariam, F. G.

    2014-01-01

    We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL’s pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components

  16. Nonuniform radiation damage in permanent magnet quadrupoles

    Energy Technology Data Exchange (ETDEWEB)

    Danly, C. R.; Merrill, F. E.; Barlow, D.; Mariam, F. G. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

    2014-08-15

    We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL’s pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.

  17. Radiation Damage in the LHCb VELO

    CERN Multimedia

    Harrison, Jon

    2011-01-01

    The VErtex LOcator (VELO) is a silicon strip detector designed to reconstruct particle tracks and vertices produced by proton-proton interactions near to the LHCb interaction point. The excellent track resolution and decay vertex separation provided by the VELO are essential to all LHCb analyses. For the integrated luminosity delivered by the LHC up to the end of $2011$ the VELO is exposed to higher particle fluences than any other silicon detector of the four major LHC experiments. These proceedings present results from radiation damage studies carried out during the first two years of data taking at the LHC. Radiation damage has been observed in all of the $88$ VELO silicon strip sensors, with many sensors showing evidence of type-inversion in the highest fluence regions. Particular attention has been given to the two \

  18. Comparative investigations of sodium arsenite, arsenic trioxide and cadmium sulphate in combination with gamma-radiation on apoptosis, micronuclei induction and DNA damage in a human lymphoblastoid cell line

    International Nuclear Information System (INIS)

    Hornhardt, Sabine; Gomolka, Maria; Walsh, Linda; Jung, Thomas

    2006-01-01

    In the field of radiation protection the combined exposure to radiation and other toxic agents is recognised as an important research area. To elucidate the basic mechanisms of simultaneous exposure, the interaction of the carcinogens and environmental toxicants cadmium and two arsenic compounds, arsenite and arsenic trioxide, in combination with gamma-radiation in human lymphoblastoid cells (TK6) were investigated. Gamma-radiation induced significant genotoxic effects such as micronuclei formation, DNA damage and apoptosis, whereas arsenic and cadmium had no significant effect on these indicators of cellular damage at non-toxic concentrations. However, in combination with gamma-radiation arsenic trioxide induced a more than additive apoptotic rate compared to the sum of the single effects. Here, the level of apoptotic cells was increased, in a dose-dependent way, up to two-fold compared to the irradiated control cells. Arsenite did not induce a significant additive effect at any of the concentrations or radiation doses tested. On the other hand, arsenic trioxide was less effective than arsenite in the induction of DNA protein cross-links. These data indicate that the two arsenic compounds interact through different pathways in the cell. Cadmium sulphate, like arsenite, had no significant effect on apoptosis in combination with gamma-radiation at low concentrations and, at high concentrations, even reduced the radiation-induced apoptosis. An additive effect on micronuclei induction was observed with 1 μM cadmium sulphate with an increase of up to 80% compared to the irradiated control cells. Toxic concentrations of cadmium and arsenic trioxide seemed to reduce micronuclei induction. The results presented here indicate that relatively low concentrations of arsenic and cadmium, close to those occurring in nature, may interfere with radiation effects. Differences in action of the two arsenic compounds were identified

  19. Genomic damage in children accidentally exposed to ionizing radiation

    DEFF Research Database (Denmark)

    Fucic, A; Brunborg, G; Lasan, R

    2007-01-01

    During the last decade, our knowledge of the mechanisms by which children respond to exposures to physical and chemical agents present in the environment, has significantly increased. Results of recent projects and programmes focused on children's health underline a specific vulnerability of chil...... and efficient preventive measures, by means of a better knowledge of the early and delayed health effects in children resulting from radiation exposure....... of children to environmental genotoxicants. Environmental research on children predominantly investigates the health effects of air pollution while effects from radiation exposure deserve more attention. The main sources of knowledge on genome damage of children exposed to radiation are studies performed...... after the Chernobyl nuclear plant accident in 1986. The present review presents and discusses data collected from papers analyzing genome damage in children environmentally exposed to ionizing radiation. Overall, the evidence from the studies conducted following the Chernobyl accident, nuclear tests...

  20. Radiation damage of uranium; Radijaciono ostecenje urana

    Energy Technology Data Exchange (ETDEWEB)

    Lazarevic, Dj [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

    1966-11-15

    Study of radiation damage covered the following: Kinetics of electric resistance of uranium and uranium alloy with 1% of molybdenum dependent on the second phase and burnup rate; Study of gas precipitation and diffusion of bubbles by transmission electron microscopy; Numerical analysis of the influence of defects distribution and concentration on the rare gas precipitation in uranium; study of thermal sedimentation of uranium alloy with molybdenum; diffusion of rare gas in metal by gas chromatography method.

  1. DNA damage caused by ionizing radiation

    International Nuclear Information System (INIS)

    Sachs, R.K.; Peili Chen; Hahnfeldt, P.J.; Klatky, L.R.

    1992-01-01

    A survey is given of continuous-time Markov chain models for ionizing radiation damage to the genome of mammalian cells. In such models, immediate damage induced by the radiation is regarded as a batch-Poisson arrival process of DNA double-strand breaks (DSBs). Enzymatic modification of the immediate damage is modeled as a Markov process similar to those described by the master equation of stochastic chemical kinetics. An illustrative example is the restitution/complete-exchange model. The model postulates that, after being induced by radiation, DSBs subsequently either undergo enzymatically mediated restitution (repair) or participate pairwise in chromosome exchanges. Some of the exchanges make irremediable lesions such as dicentric chromosome aberrations. One may have rapid irradiation followed by enzymatic DSB processing or have prolonged irradiation with both DSB arrival and enzymatic DSB processing continuing throughout the irradiation period. Methods for analyzing the Markov chains include using an approximate model for expected values, the discrete-time Markov chain embedded at transitions, partial differential equations for generating functions, normal perturbation theory, singular perturbation theory with scaling, numerical computations, and certain matrix methods that combine Perron-Frobenius theory with variational estimates. Applications to experimental results on expected values, variances, and statistical distributions of DNA lesions are briefly outlined. Continuous-time Markov chains are the most systematic of those radiation damage models that treat DSB-DSB interactions within the cell nucleus as homogeneous (e.g., ignore diffusion limitations). They contain virtually all other relevant homogeneous models and semiempirical summaries as special cases, limiting cases, or approximations. However, the Markov models do not seem to be well suited for studying spatial dependence of DSB interactions. 51 refs., 5 figs

  2. Pathology of radiation induced lung damage

    International Nuclear Information System (INIS)

    Kawabata, Yoshinori; Murata, Yoshihiko; Ogata, Hideo; Katagiri, Shiro; Sugita, Hironobu; Iwai, Kazuo; Sakurai, Isamu.

    1985-01-01

    We examined pathological findings of radiation induced lung damage. Twenty-three cases are chosen from our hospital autopsy cases for 9 years, which fulfil strict criteria of radiation lung damage. Lung damage could be classified into 3 groups : 1) interstitial pneumonia type (9 cases), 2) intermediate pneumonia type (8 cases), and 3) alveolar pneumonia type (6 cases), according to the degree of intra-luminal exudation. These classification is well correlated with clinical findings. Pathological alveolar pneumonia type corresponds to symptomatic, radiologic ground glass pneumonic shadow. And pathologic interstitial type corresponds to clinical asymptomatic, radiologic reticulo-nodular shadow. From the clinico-pathological view point these classification is reasonable one. Radiation affects many lung structures and showed characteristic feature of repair. Elastofibrosis of the alveolar wall is observed in every cases, obstructive bronchiolitis are observed in 5 cases, and obstructive bronchiolitis in 9 cases. They are remarkable additional findings. Thickening of the interlobular septum, broncho-vascular connective tissue, and pleural layer are observed in every cases together with vascular lesions. (author)

  3. Radiation damage in CTR magnet components

    International Nuclear Information System (INIS)

    Ullmaier, H.

    1976-01-01

    Data are reviewed (already existing or to be acquired) which should allow prediction of the behavior of large superconducting coils in the radiation field of a future fusion reactor. The electrical and mechanical stability of such magnets is determined by the irradiation induced deterioration of the magnet components, i.e., (a) changes in critical current, field and temperature of the superconductor (NbTi, A-15 phases), (b) resistivity increase in the stabilizer (Cu, Al), and (c) changes in mechanical and dielectric properties of insulators and spacers. Recent low temperature simulation experiments (with fission neutrons and heavy ions) show that the superconductor will not be the critical component of a fusion magnet--at least as far as radiation damage is concerned. Much more severe is the loss of stability due to the resistivity increase of the stabilizing material. It seems, however, that the magnitude of this effect can be predicted rather reliably and therefore taken into account in the coil design. Almost no data exist about the low temperature behavior of insulator and spacer materials in a radiation field. Furthermore, very little is known about the nature of the radiation damage in non-metals, which makes extrapolations of the few existing data to other materials or to other doses highly speculative. Only future experiments can decide if the insulators will be the limiting component of a CTR magnet or not

  4. Investigation of DNA damage and repair mechanism using deinococcus radiodurans

    International Nuclear Information System (INIS)

    Lau How Mooi; Kikuchi, M.; Kobayashi, Y.; Narumi, I.; Watanabe, H.

    1997-01-01

    Deninococcus Radiodurans, formerly known as Micrococcus Radiodurans, is a popular bacterium because of its high resistance to damage by carcinogens such as ionizing radiation (Dean et. al. 1966; Kitayama and Matsuyama 1968) and UV radiation (Gasvon et. al., 1995; Arrange et. al. 1993). In this report, we investigated the high resistance to ionizing radiation by this bacterium. The bacteria had been exposed from I to 5 kGy of gamma radiation and then incubated in TGY medium to study their ability to repair the broken DNA. The repair time was measured by Pulse Field Gel Electrophoresis (PFGE) method. The repair time for each dose was determined. Also in order to ensure that the repair was perfect, the bacterium was subjected to a second exposure of ionizing radiation after it has fully repaired. It was found that the 'second' repair characteristic was similar to the first repair. This confirmed that the repair after the exposure to the ionizing radiation was perfect

  5. Radiation damage in the alkali halide crystals

    International Nuclear Information System (INIS)

    Diller, K.M.

    1975-10-01

    A general review is given of the experimental data on radiation damage in the alkali halide crystals. A report is presented of an experimental investigation of irradiation produced interstitial dislocation loops in NaCl. These loops are found to exhibit the usual growth and coarsening behaviour during thermal annealing which operates by a glide and self-climb mechanism. It is shown that the recombination of defects in these crystals is a two stage process, and that the loss of interstitials stabilized at the loops is caused by extrinsic vacancies. The theoretical techniques used in simulating point defects in ionic crystals are described. Shell model potentials are derived for all the alkali halide crystals by fitting to bulk crystal data. The fitting is supplemented by calculations of the repulsive second neighbour interactions using methods based on the simple electron gas model. The properties of intrinsic and substitutional impurity defects are calculated. The HADES computer program is used in all the defect calculations. Finally the report returns to the problems of irradiation produced interstitial defects. The properties of H centres are discussed; their structure, formation energies, trapping at impurities and dimerization. The structure, formation energies and mobility of the intermediate and final molecular defects are then discussed. The thermodynamics of interstitial loop formation is considered for all the alklai halide crystals. The nucleation of interstitial loops in NaCl and NaBr is discussed, and the recombination of interstitial and vacancy defects. The models are found to account for all the main features of the experimental data. (author)

  6. Radiation induced crystallinity damage in poly(L-lactic acid)

    CERN Document Server

    Kantoglu, O

    2002-01-01

    The radiation-induced crystallinity damage in poly(L-lactic acid) (PLLA) in the presence of air and in vacuum, is studied. From the heat of fusion enthalpy values of gamma irradiated samples, some changes on the thermal properties were determined. To identify these changes, first the glass transition temperature (T sub g) of L-lactic acid polymers irradiated to various doses in air and vacuum have been investigated and it is found that it is independent of irradiation atmosphere and dose. The fraction of damaged units of PLLA per unit of absorbed energy has been measured. For this purpose, SAXS and differential scanning calorimetry methods were used, and the radiation yield of number of damaged units (G(-u)) is found to be 0.74 and 0.58 for PLLA samples irradiated in vacuum and air, respectively.

  7. Radiation damage studies for the D0 silicon detector

    International Nuclear Information System (INIS)

    Lehner, F.

    2004-01-01

    We report on irradiation studies performed on spare production silicon detector modules for the current D0 silicon detector. The lifetime expectations due to radiation damage effects of the existing silicon detector are reviewed. A new upgrade project was started with the goal of a complete replacement of the existing silicon detector. In that context, several investigations on the radiation hardness of new prototype silicon microstrip detectors were carried out. The irradiation on different detector types was performed with 10 MeV protons up to fluences of 10 14 p/cm 2 at the J.R. Mcdonald Laboratory at Kansas State University. The flux calibration was carefully checked using different normalization techniques. As a result, we observe roughly 40-50% less radiation damage in silicon for 10 MeV p exposure than it is expected by the predicted NIEL scaling

  8. Radiation damage studies for the DOe silicon detector

    International Nuclear Information System (INIS)

    Lehner, Frank

    2004-01-01

    We report on irradiation studies performed on spare production silicon detector modules for the current DOe silicon detector. The lifetime expectations due to radiation damage effects of the existing silicon detector are reviewed. A new upgrade project was started with the goal of a complete replacement of the existing silicon detector. In that context, several investigations on the radiation hardness of new prototype silicon microstrip detectors were carried out. The irradiation on different detector types was performed with 10 MeV protons up to fluences of 10 14 p/cm 2 at the J.R. Mcdonald Laboratory at Kansas State University. The flux calibration was carefully checked using different normalisation techniques. As a result, we observe roughly 40-50% less radiation damage in silicon for 10 MeV p exposure than it is expected by the predicted NIEL scaling

  9. Involvement of membrane lipids in radiation damage to potassium-ion permeability of Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, S [Tokyo Univ. (Japan). Inst. for Medical Science; Akamatsu, Y

    1978-02-01

    Radiation damage to K/sup +/ permeability of an unsaturated fatty acid auxotroph of E.coli grown with oleate or linolenate was investigated at different temperatures. A remarkable effect of radiation was observed at 0/sup 0/C with cells that had been grown in linolenate at 42/sup 0/C. This indicates that, besides protein, membrane lipids at least are involved in the radiation damage. The damage also seems to be affected by the fluidity of membrane lipids.

  10. Radiation damage effects in solids special topic volume with invited peer reviewed papers only

    CERN Document Server

    Virk, Hardev Singh

    2013-01-01

    Public interest and concern about radiation damage effects has increased during recent times. Nuclear radiation proved to be a precursor for the study of radiation damage effects in solids. In general, all types of radiation, e.g. X-ray, gamma ray, heavy ions, fission fragments and neutrons produce damage effects in materials. Radiation damage latent tracks in solids find applications in nuclear and elementary particle physics, chemistry, radiobiology, earth sciences, nuclear engineering, and a host of other areas such as nuclear safeguards, virus counting, ion track filters, uranium exploration and archaeology. Radiation dosimetry and reactor shielding also involve concepts based on radiation damage in solids. This special volume consists of ten Chapters, including Review and Research Papers on various topics in this field.Physical scientists known to be investigating the effects of radiation on material were invited to contribute research and review papers on the areas of their specialty. The topics include...

  11. Studies on the strategies of minimizing radiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Hee Yong; Sohn, Young Sook

    1998-04-01

    We studied on the strategies of minimizing radiation damage in animal system. To this end we studied following areas of research (1) mechanisms involved in bone marrow damage after total body irradiation, (2) extraction of components that are useful in protecting hematopoietic system from radiation damage, (3) cell therapy approach in restoring the damaged tissue, (4) development of radioprotective chemical reagent, and (5) epidemiological study on the population that had been exposed to radiation.

  12. Studies on the strategies of minimizing radiation damage

    International Nuclear Information System (INIS)

    Chung, Hee Yong; Sohn, Young Sook

    1998-04-01

    We studied on the strategies of minimizing radiation damage in animal system. To this end we studied following areas of research 1) mechanisms involved in bone marrow damage after total body irradiation, 2) extraction of components that are useful in protecting hematopoietic system from radiation damage, 3) cell therapy approach in restoring the damaged tissue, 4) development of radioprotective chemical reagent, and 5) epidemiological study on the population that had been exposed to radiation

  13. Compilation of radiation damage test data. I

    International Nuclear Information System (INIS)

    Schoenbacher, H.; Stolarz-Izycka, A.

    1979-01-01

    This report summarizes radiation damage test data on commercially available organic cable insulation and jacket materials: ethylene-propylene rubber, Hypalon, neoprene rubber, polyethylene, polyurethane, polyvinylchloride, silicone rubber, etc. The materials have been irradiated in a nuclear reactor to integrated absorbed doses from 5 X 10 5 to 5 X 10 6 Gy. Mechanical properties, e.g. tensile strength, elongation at break, and hardness, have been tested on irradiated and non-irradiated samples. The results are presented in the form of tables and graphs, to show the effect of the absorbed dose on the measured properties. (Auth.)

  14. Radiation damage to DNA-protein complexes

    Czech Academy of Sciences Publication Activity Database

    Spotheim-Maurizot, M.; Davídková, Marie

    2011-01-01

    Roč. 261, zima (2011), s. 1-10 ISSN 1742-6588. [COST Chemistry CM0603-MELUSYN Joint Meeting Damages Induced in Biomolecules by Low and High Energy Radiations. Paříž, 09.03.2010-12.03.2010] R&D Projects: GA AV ČR IAA1048103; GA AV ČR KJB4048401; GA MŠk 1P05OC085; GA MŠk OC09012; GA AV ČR IAB1048901 Institutional research plan: CEZ:AV0Z10480505 Keywords : radiolysis * molecular-dynamics simulation * hydroxyl radical attack * induced strand breakage Subject RIV: BO - Biophysics

  15. Ultraviolet radiation, sun damage and preventing

    International Nuclear Information System (INIS)

    Johnsen, B.; Christensen, T.; Nilsen, L.T.; Hannevik, M.

    2013-01-01

    The report focuses on the large impact of health damages due to excessive UV exposure from natural sun. The first part of the report gives background information on factors significantly affecting the intensity of UV radiation. The second part gives an overview of health effects related to UV exposure, with recommendations on how to avoid excessive UV exposure and still enjoy the positive sides of outdoor activity. The report is intended to contribute to informational activities about sun exposure as recommended by the World Health Organisation and the World Meteorology Organisation. (Author)

  16. Radiation damage calculations for the LANSCE degrader

    International Nuclear Information System (INIS)

    Ferguson, P.D.; Sommer, W.F.; Dudziak, D.J.; Wechsler, M.S.; Barnett, M.H.; Corzine, R.K.

    1998-01-01

    The A-6 water degrader at the Los Alamos Neutron Science Center (LANSCE) linear proton accelerator has an outer shell of Inconel 718. The degrader was irradiated by 800-MeV protons during 1988--1993 to an exposure of 5.3 ampere-hours (A h). As described in Ref. 1, material from the Inconel is currently being cut into specimens for microhardness, three-point bending, ball punch, microscopy, and corrosion tests. This paper is devoted to calculations of radiation damage, particularly displacement and He production, sustained by the degrader Inconel

  17. Neutron radiation damage studies on silicon detectors

    International Nuclear Information System (INIS)

    Li, Zheng; Chen, W.; Kraner, H.W.

    1990-10-01

    Effects of neutron radiation on electrical properties of Si detectors have been studied. At high neutron fluence (Φ n ≥ 10 12 n/cm 2 ), C-V characteristics of detectors with high resistivities (ρ ≥ 1 kΩ-cm) become frequency dependent. A two-trap level model describing this frequency dependent effect is proposed. Room temperature anneal of neutron damaged (at LN 2 temperature) detectors shows three anneal stages, while only two anneal stages were observed in elevated temperature anneal. 19 refs., 14 figs

  18. Ultraviolet Radiations: Skin Defense-Damage Mechanism.

    Science.gov (United States)

    Mohania, Dheeraj; Chandel, Shikha; Kumar, Parveen; Verma, Vivek; Digvijay, Kumar; Tripathi, Deepika; Choudhury, Khushboo; Mitten, Sandeep Kumar; Shah, Dilip

    2017-01-01

    UV-radiations are the invisible part of light spectra having a wavelength between visible rays and X-rays. Based on wavelength, UV rays are subdivided into UV-A (320-400 nm), UV-B (280-320 nm) and UV-C (200-280 nm). Ultraviolet rays can have both harmful and beneficial effects. UV-C has the property of ionization thus acting as a strong mutagen, which can cause immune-mediated disease and cancer in adverse cases. Numbers of genetic factors have been identified in human involved in inducing skin cancer from UV-radiations. Certain heredity diseases have been found susceptible to UV-induced skin cancer. UV radiations activate the cutaneous immune system, which led to an inflammatory response by different mechanisms. The first line of defense mechanism against UV radiation is melanin (an epidermal pigment), and UV absorbing pigment of skin, which dissipate UV radiation as heat. Cell surface death receptor (e.g. Fas) of keratinocytes responds to UV-induced injury and elicits apoptosis to avoid malignant transformation. In addition to the formation of photo-dimers in the genome, UV also can induce mutation by generating ROS and nucleotides are highly susceptible to these free radical injuries. Melanocortin 1 receptor (MC1R) has been known to be implicated in different UV-induced damages such as pigmentation, adaptive tanning, and skin cancer. UV-B induces the formation of pre-vitamin D3 in the epidermal layer of skin. UV-induced tans act as a photoprotection by providing a sun protection factor (SPF) of 3-4 and epidermal hyperplasia. There is a need to prevent the harmful effects and harness the useful effects of UV radiations.

  19. Radiation damage in non-metals

    International Nuclear Information System (INIS)

    Stoneham, A.M.

    1980-01-01

    Work on the problem of radiation damage in non-metals over the past 25 years is reviewed with especial emphasis on the contribution made at AERE, Harwell and in particular by members of the Theoretical Physics Division. In the years between 1954 and the end of the 1960's the main thrust in the radiation damage of non-metals was model-building including devising defect models and mechanisms that were qualitatively acceptable, and compiling systematic data. The early 1970's made greater quantitative demands as computer techniques made theory more powerful. In many cases it was possible to predict defect properties accurately, so that one could distinguish between different defect models which were hard to tell apart by experiment alone. In the late 1970's the most important aspect has moved towards mechanisms of defect processes, especially in cases where experiment by itself is limited by timescale, by complexity, by the unintentional impurities inevitable in real crystals, or by the extreme conditions required. (UK)

  20. Radiation damage to DNA-binding proteins

    International Nuclear Information System (INIS)

    Culard, G.; Eon, S.; DeVuyst, G.; Charlier, M.; Spotheim-Maurizot, M.

    2003-01-01

    The DNA-binding properties of proteins are strongly affected upon irradiation. The tetrameric lactose repressor (a dimer of dimers) losses its ability to bind operator DNA as soon as at least two damages per protomer of each dimer occur. The monomeric MC1 protein losses its ability to bind DNA in two steps : i) at low doses only the specific binding is abolished, whereas the non-specific one is still possible; ii) at high doses all binding vanishes. Moreover, the DNA bending induced by MC1 binding is less pronounced for a protein that underwent the low dose irradiation. When the entire DNA-protein complexes are irradiated, the observed disruption of the complexes is mainly due to the damage of the proteins and not to that of DNA. The doses necessary for complex disruption are higher than those inactivating the free protein. This difference, larger for MC1 than for lactose repressor, is due to the protection of the protein by the bound DNA. The oxidation of the protein side chains that are accessible to the radiation-induced hydroxyl radicals seems to represent the inactivating damage

  1. Solar radiation and mitochondrial DNA damage

    International Nuclear Information System (INIS)

    Hill, H.Z.; Locitzer, J.; Nassrin, E.; Ogbonnaya, A.; Hubbard, K.

    2003-01-01

    The 16.6 kB human mitochondrial DNA contains two homologous 13 base pair direct repeats separated by about 5 kB. During asynchronous mitochondrial DNA replication, the distant repeat sequences are thought to anneal, resulting in the looping out of a portion of the non-template strand which is subsequently deleted as a result of interaction with reactive oxygen species (ROS). A normal daughter and a deleted daughter mitochondrion result from such insults. This deletion has been termed the common deletion as it is the most frequent of the known mitochondrial DNA deletions. The common deletion is present in high frequency in several mitochondrial disorders, accumulates with age in slow turnover tissues and is increased in sun-exposed skin. Berneburg, et al. (Photochem. Photobiol. 66: 271, 1997) induced the common deletion in normal human fibroblasts after repeated exposures to UVA. In this study, the common deletion has been shown to be induced by repeated non-lethal exposures to FS20 sunlamp irradiation. Increases in the common deletion were demonstrated using nested PCR which produced a 303 bp product that was compared to a 324 bp product that required the presence of the undeleted 5 kB region. The cells were exposed to 10 repeated doses ranging from 0.5 (UVB) - 0.24 (UVA) J/sq m to 14.4 (UVB) - 5.8 J/sq m (UVA) measured using a UVX digital radiometer and UVB and UVA detectors respectively. Comparison with the earlier study by Berneberg, et al. suggests that this type of simulated solar damage is considerably more effective in fewer exposures than UVA radiation alone. The common deletion provides a cytoplasmic end-point for ROS damage produced by low dose chronic irradiations and other low level toxic exposures and should prove useful in evaluating cytoplasmic damage produced by ionizing radiation as well

  2. Molecular mechanisms in radiation damage to DNA: Final report

    International Nuclear Information System (INIS)

    Osman, R.

    1996-01-01

    The objectives of this work were to elucidate the molecular mechanisms that were responsible for radiation-induced DNA damage. The studies were based on theoretical explorations of possible mechanisms that link initial radiation damage in the form of base and sugar damage to conformational changes in DNA

  3. Computer simulations of radiation damage in protein crystals; Simulationsrechnungen zu Strahlenschaeden an Proteinkristallen

    Energy Technology Data Exchange (ETDEWEB)

    Zehnder, M

    2007-03-15

    The achievable resolution and the quality of the dataset of an intensity data collection for structure analysis of protein crystals with X-rays is limited among other factors by radiation damage. The aim of this work is to obtain a better quantitative understanding of the radiation damage process in proteins. Since radiation damage is unavoidable it was intended to look for the optimum ratio between elastically scattered intensity and radiation damage. Using a Monte Carlo algorithm physical processes after an inelastic photon interaction are studied. The main radiation damage consists of ionizations of the atoms through the electron cascade following any inelastic photon interaction. Results of the method introduced in this investigation and results of an earlier theoretical studies of the influence of Auger-electron transport in diamond are in a good agreement. The dependence of the radiation damage as a function of the energy of the incident photon was studied by computer-aided simulations. The optimum energy range for diffraction experiments on the protein myoglobin is 10-40 keV. Studies of radiation damage as a function of crystal volume and shape revealed that very small plate or rod shaped crystals suffer less damage than crystals formed like a cube with the same volume. Furthermore the influence of a few heavy atoms in the protein molecule on radiation damage was examined. Already two iron atoms in the unit cell of myoglobin increase radiation damage significantly. (orig.)

  4. Thermal Decomposition of Radiation-Damaged Polystyrene

    International Nuclear Information System (INIS)

    J Abrefah, J.; Klinger, G.S.

    2000-01-01

    The radiation-damaged polystyrene material (''polycube'') used in this study was synthesized by mixing a high-density polystyrene (''Dylene Fines No. 100'') with plutonium and uranium oxides. The polycubes were used on the Hanford Site in the 1960s for criticality studies to determine the hydrogen-to-fissile atom ratios for neutron moderation during processing of spent nuclear fuel. Upon completion of the studies, two methods were developed to reclaim the transuranic (TRU) oxides from the polymer matrix: (1) burning the polycubes in air at 873 K; and (2) heating the polycubes in the absence of oxygen and scrubbing the released monomer and other volatile organics using carbon tetrachloride. Neither of these methods was satisfactory in separating the TRU oxides from the polystyrene. Consequently, the remaining polycubes were sent to the Hanford Plutonium Finishing Plant (PFP) for storage. Over time, the high dose of alpha and gamma radiation has resulted in a polystyrene matrix that is highly cross-linked and hydrogen deficient and a stabilization process is being developed in support of Defense Nuclear Facility Safety Board Recommendation 94-1. Baseline processes involve thermal treatment to pyrolyze the polycubes in a furnace to decompose the polystyrene and separate out the TRU oxides. Thermal decomposition products from this degraded polystyrene matrix were characterized by Pacific Northwest National Laboratory to provide information for determining the environmental impact of the process and for optimizing the process parameters. A gas chromatography/mass spectrometry (GC/MS) system coupled to a horizontal tube furnace was used for the characterization studies. The decomposition studies were performed both in air and helium atmospheres at 773 K, the planned processing temperature. The volatile and semi-volatile organic products identified for the radiation-damaged polystyrene were different from those observed for virgin polystyrene. The differences were in the

  5. Radiation damage assessment of Nb tunnel junction devices

    International Nuclear Information System (INIS)

    King, S.E.; Magno, R.; Maisch, W.G.

    1991-01-01

    This paper reports on the radiation hardness of a new technology using Josephson junctions that was explored by an irradiation using a fluence of 7.6 x 10 14 protons/cm 2 at an energy of 63 MeV from the U.C. Davis cyclotron. In what the authors believe is the first radiation assessment of Nb/Al 2 O 3 /Nb devices, the permanent damage in these devices was investigated. No permanent changes in the I-V characteristics of the junctions were observed indicating no significant level of material defects have occurred at this level of irradiation

  6. Functional analysis of molecular mechanisms of radiation induced apoptosis, that are not mediated by DNA damages

    International Nuclear Information System (INIS)

    Angermeier, Marita; Moertl, Simone

    2012-01-01

    The effects of low-dose irradiation pose new challenges on the radiation protection efforts. Enhanced cellular radiation sensitivity is displayed by disturbed cellular reactions and resulting damage like cell cycle arrest, DNA repair and apoptosis. Apoptosis serves as genetically determinate parameter for the individual radiation sensitivity. In the frame of the project the radiation-induced apoptosis was mechanistically investigated. Since ionizing radiation induced direct DNA damage and generates a reactive oxygen species, the main focus of the research was the differentiation and weighting of DNA damage mediated apoptosis and apoptosis caused by the reactive oxygen species (ROS).

  7. Radiation Damage In Reactor Cavity Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G [ORNL; Le Pape, Yann [ORNL; Naus, Dan J [ORNL; Remec, Igor [ORNL; Busby, Jeremy T [ORNL; Rosseel, Thomas M [ORNL; Wall, Dr. James Joseph [Electric Power Research Institute (EPRI)

    2015-01-01

    License renewal up to 60 years and the possibility of subsequent license renewal to 80 years has established a renewed focus on long-term aging of nuclear generating stations materials, and recently, on concrete. Large irreplaceable sections of most nuclear generating stations include concrete. The Expanded Materials Degradation Analysis (EMDA), jointly performed by the Department of Energy, the Nuclear Regulatory Commission and Industry, identified the urgent need to develop a consistent knowledge base on irradiation effects in concrete. Much of the historical mechanical performance data of irradiated concrete does not accurately reflect typical radiation conditions in NPPs or conditions out to 60 or 80 years of radiation exposure. To address these potential gaps in the knowledge base, The Electric Power Research Institute and Oak Ridge National Laboratory are working to disposition radiation damage as a degradation mechanism. This paper outlines the research program within this pathway including: (i) defining the upper bound of the neutron and gamma dose levels expected in the biological shield concrete for extended operation (80 years of operation and beyond), (ii) determining the effects of neutron and gamma irradiation as well as extended time at temperature on concrete, (iii) evaluating opportunities to irradiate prototypical concrete under accelerated neutron and gamma dose levels to establish a conservative bound and share data obtained from different flux, temperature, and fluence levels, (iv) evaluating opportunities to harvest and test irradiated concrete from international NPPs, (v) developing cooperative test programs to improve confidence in the results from the various concretes and research reactors, (vi) furthering the understanding of the effects of radiation on concrete (see companion paper) and (vii) establishing an international collaborative research and information exchange effort to leverage capabilities and knowledge.

  8. Compilation of radiation damage test data

    International Nuclear Information System (INIS)

    Schoenbacher, H.; Tavlet, M.

    1989-01-01

    This report summarizes radiation damage test data on commercially available organic cable insulation and jacket materials: Ethylene-propylene rubbers, polyethylenes, polyurethanes, silicone rubbers, and copolymers based on polyethylene. The materials have been irradiated either in a nuclear reactor, or with a cobalt-60 source, or in the CERN accelerators, at different dose rates. The absorbed doses were between 10 3 and 5x10 6 Gy. Mechanical properties, e.g. tensile strength, elongation at break, and hardness, have been tested on irradiated and non-irradiated samples, according to the recommendations of the International Electrotechnical Commission. The results are presented in the form of tables and graphs to show the effect of the absorbed dose on the measured properties. (orig.)

  9. Compilation of radiation damage test data. II

    International Nuclear Information System (INIS)

    Schoenbacher, H.; Stolarz-Izycka, A.

    1979-01-01

    This report summarizes radiation damage test data on thermosetting and thermoplastic resins, with the main emphasis on epoxy resins used for magnet coil insulations. Also, other materials such as polyesters, phenolics, polyurethanes, silicones, etc., are represented. The materials have been irradiated in a nuclear reactor to integrated absorbed doses between 5x10 6 Gy and 1x10 8 Gy. The mechanical properties, e.g. the flexural strength, deflection at break, and tangent modulus of elasticity, have been measured on irradiated and non-irradiated samples. The results are given as variation of these parameters versus absorbed dose and are presented in the form of tables and graphs. The tested materials are catalogued in alphabetical order. (Auth.)

  10. Measurement of radiation damage on an optical reflector

    International Nuclear Information System (INIS)

    Peng, K.C.; Sahu, S.K.; Huang, H.C.; Ueno, K.; Chang, Y.H.; Wang, C.H.; Hou, W.S.

    1997-01-01

    We measured the radiation damage on an optical white fluorocarbon reflector called Goretex, which is to be used for aerogel threshold counters and crystal calorimeters of the BELLE detector of the KEK B-factory. Reflectance of the Goretex surface was monitored to see any effect of the radiation damage. Maximum equivalent dose was 8.6 Mrad. No radiation damage is observed within measurement errors. (orig.)

  11. Thermal annealing of natural, radiation-damaged pyrochlore

    Energy Technology Data Exchange (ETDEWEB)

    Zietlow, Peter; Mihailova, Boriana [Hamburg Univ. (Germany). Dept. of Earth Sciences; Beirau, Tobias [Hamburg Univ. (Germany). Dept. of Earth Sciences; Stanford Univ., CA (United States). Dept. of Geological Sciences; and others

    2017-03-01

    Radiation damage in minerals is caused by the α-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400-1000 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia [6.4 wt% Th, 23.1.10{sup 18} α-decay events per gram (dpg)], Panda Hill/Tanzania (1.6 wt% Th, 1.6.10{sup 18} dpg), and Blue River/Canada (10.5 wt% U, 115.4.10{sup 18} dpg), are compared with a crystalline reference pyrochlore from Schelingen (Germany). The type of structural recovery depends on the initial degree of radiation damage (Panda Hill 28%, Blue River 85% and Miass 100% according to XRD), as the recrystallization temperature increases with increasing degree of amorphization. Raman spectra indicate reordering on the local scale during annealing-induced recrystallization. As Raman modes around 800 cm{sup -1} are sensitive to radiation damage (M. T. Vandenborre, E. Husson, Comparison of the force field in various pyrochlore families. I. The A{sub 2}B{sub 2}O{sub 7} oxides. J. Solid State Chem. 1983, 50, 362, S. Moll, G. Sattonnay, L. Thome, J. Jagielski, C. Decorse, P. Simon, I. Monnet, W. J. Weber, Irradiation damage in Gd{sub 2}Ti{sub 2}O{sub 7} single crystals: Ballistic versus ionization processes. Phys. Rev. 2011, 84, 64115.), the degree of local order was deduced from the ratio of the integrated intensities of the sum of the Raman bands between 605 and 680 cm{sup -1} divided by the sum of the integrated intensities of the bands between 810 and 860 cm{sup -1}. The most radiation damaged pyrochlore (Miass) shows an abrupt recovery of both, its short- (Raman) and long-range order (X-ray) between 800 and 850 K, while the weakly damaged pyrochlore (Panda Hill) begins to recover at considerably lower temperatures (near 500 K

  12. Spallation radiation damage and the radiation damage facility at the LAMPF A-6 target station

    Energy Technology Data Exchange (ETDEWEB)

    Wechsler, M.S.; Sommer, W.F. (Los Alamos National Lab., NM (USA))

    1984-05-01

    A redesign of the Clinton P. Anderson Los Alamos Meson Physics Facility (LAMPF) A-6 Target Station is underway that will permit materials irradiations to be conducted in the proton beam and in the spallation neutron environment under more controlled conditions than has been possible heretofore. The protons of energy near 800 MeV and beam current approaching one mA are able to produce radiation damage rates (displacement production rates) as high as can be achieved in fission reactors, and the damage is uniform over macroscopic dimensions. The spallation neutrons have a degraded fission spectrum energy distribution, with the important admixture of a high energy tail up to 800 MeV. Irradiations in these radiation environments can be used to address important problems in the development of materials for fusion reactors. The redesign of the A-6 Target Station is described and plans for its use are discussed.

  13. Low dose radiation damage effects in silicon strip detectors

    International Nuclear Information System (INIS)

    Wiącek, P.; Dąbrowski, W.

    2016-01-01

    The radiation damage effects in silicon segmented detectors caused by X-rays have become recently an important research topic driven mainly by development of new detectors for applications at the European X-ray Free Electron Laser (E-XFEL). However, radiation damage in silicon strip is observed not only after extreme doses up to 1 GGy expected at E-XFEL, but also at doses in the range of tens of Gy, to which the detectors in laboratory instruments like X-ray diffractometers or X-ray spectrometers can be exposed. In this paper we report on investigation of radiation damage effects in a custom developed silicon strip detector used in laboratory diffractometers equipped with X-ray tubes. Our results show that significant degradation of detector performance occurs at low doses, well below 200 Gy, which can be reached during normal operation of laboratory instruments. Degradation of the detector energy resolution can be explained by increasing leakage current and increasing interstrip capacitance of the sensor. Another observed effect caused by accumulation of charge trapped in the surface oxide layer is change of charge division between adjacent strips. In addition, we have observed unexpected anomalies in the annealing process.

  14. Low dose radiation damage effects in silicon strip detectors

    Science.gov (United States)

    Wiącek, P.; Dąbrowski, W.

    2016-11-01

    The radiation damage effects in silicon segmented detectors caused by X-rays have become recently an important research topic driven mainly by development of new detectors for applications at the European X-ray Free Electron Laser (E-XFEL). However, radiation damage in silicon strip is observed not only after extreme doses up to 1 GGy expected at E-XFEL, but also at doses in the range of tens of Gy, to which the detectors in laboratory instruments like X-ray diffractometers or X-ray spectrometers can be exposed. In this paper we report on investigation of radiation damage effects in a custom developed silicon strip detector used in laboratory diffractometers equipped with X-ray tubes. Our results show that significant degradation of detector performance occurs at low doses, well below 200 Gy, which can be reached during normal operation of laboratory instruments. Degradation of the detector energy resolution can be explained by increasing leakage current and increasing interstrip capacitance of the sensor. Another observed effect caused by accumulation of charge trapped in the surface oxide layer is change of charge division between adjacent strips. In addition, we have observed unexpected anomalies in the annealing process.

  15. The annealing of radiation damage in type Ia diamond

    International Nuclear Information System (INIS)

    Collins, Alan T; Kiflawi, Isaac

    2009-01-01

    The kinetics of the recovery of radiation damage in type Ia diamond has been investigated using isothermal annealing at 600 deg. C. In diamonds having a reasonably homogeneous distribution of nitrogen the decay of the vacancy concentration with time can be approximately described by a single exponential. Previous investigations have identified 'fast' and 'slow' components in the annealing, and we show that the existence of more than one time constant is associated with inhomogeneous nitrogen concentrations. The measurements show further that, in order to obtain the oscillator strengths of nitrogen-vacancy centres, studies must be restricted to diamonds with moderately high nitrogen concentrations.

  16. 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

  17. Basic aspects of spallation radiation damage to materials

    Energy Technology Data Exchange (ETDEWEB)

    Wechsler, M.S.; Lin, C. [North Carolina State Univ., Raleigh, NC (United States); Sommer, W.F. [Los Alamos National Laboratory, NM (United States)

    1995-10-01

    The nature of radiation effects, as learned from investigations using reactor neutron irradiations, is reviewed, and its relevance to spallation radiation damage to materials in accelerator-driven neutron sources is discussed. Property changes upon irradiation are due to (1) displaced atoms, producing vacancy and interstitial defect clusters, which cause radiation hardening and embrittlement; (2) helium production, the helium then forming bubbles, which engenders high-temperature grain-boundary fracture; and (3) transmutations, which means that impurity concentrations are introduced. Methods for analyzing displacement production are related, and recent calculations of displacement cross sections using SPECTER and LAHET are described, with special reference to tungsten, a major candidate for a target material in accelerator-driven neutron systems.

  18. Radiation damage: special reference to gas filled radiation detectors

    International Nuclear Information System (INIS)

    Gaur, Sudha; Joshi, Pankaj Kumar; Rathore, Shakuntla

    2012-01-01

    Radiation damage is a term associated with ionizing radiation. In gas filled particle detectors, radiation damage to gases plays an important role in the device's ageing, especially in devices exposed to high intensity radiation, e.g. detector for the large hadrons collide. Ionization processes require energy above 10 eV, while splitting covalent bond in molecules and generating free radical require only 3-4 eV. The electrical discharges initiated by the ionization event by the particles result in plasma populated by large amount of free radical. The highly reactive free radical can recombine back to original molecules, or initiate a chain of free radical polymerization reaction with other molecules, yielding compounds with increasing molecular weight. These high molecular weight compounds then precipitate from gases phase, forming conductive or non-conductive deposits on the electrodes an insulating surfaces of the detector and distorting it's response. Gases containing hydrocarbon quenchers, e.g. argon-methane, are typically sensitive to ageing by polymerization; addition of oxygen tends to lower the ageing rates. Trace amount of silicon oils, present form out gassing of silicon elastomers and especially from traces of silicon lubricant tend to decompose and form deposits of silicon crystals on the surfaces. Gases mixture of argon (or xenon) with CO 2 and optimally also with 2-3 % of oxygen are highly tolerant to high radiation fluxes. The oxygen is added as noble gas with CO 2 has too high transparency for high energy photons; ozone formed from the oxygen is a strong absorber of ultra violet photons. Carbon tetra fluoride can be used as a component of the gas for high-rate detectors; the fluorine radical produced during the operation however limit the choice of materials for the chambers and electrodes (e.g. gold electrodes are required, as the fluorine radicals attack metals, forming fluorides). Addition of carbon tetra fluoride can however eliminate the

  19. Radiation damage to integrated injection logic cells

    International Nuclear Information System (INIS)

    Pease, R.L.; Galloway, K.F.; Stehlin, R.A.

    1975-01-01

    The effects of neutron and total dose gamma irradiations on the electrical characteristics of an integrated injection logic (l 2 L) cell and an l 2 L multiple inverter circuit were investigated. These units were designed and fabricated to obtain circuit development information and did not have radiation hardness as a goal. The following parameters of the test structures were measured as a function of total dose and neutron fluence: the dc common-base current gain of the lateral pnp transistor; the dc common-emitter current gain of the vertical npn transistor; the forward current-voltage characteristics of the injector-substrate junction, and the propagation delay versus power dissipation per gate for the multiple inverter circuit. The limitations of the present test structures in a radiation environment and possible hardening techniques are discussed

  20. Radiation damage of DNA. Model for direct ionization of DNA

    International Nuclear Information System (INIS)

    Kobayashi, Kazuo; Tagawa, Seiichi

    2004-01-01

    Current aspects of radiation damage of DNA, particularly induced by the direct effect of radiation, and author's method of pulse radiolysis are described in relation to behavior of ions formed by radiation and active principles to induce the strand break. In irradiation of DNA solution in water, the direct effect of radiation is derived from ionization of DNA itself and indirect one, from the reaction between DNA and radicals generated from water molecules and the former direct one has been scarcely investigated due to difficulty of experimental approach. Radicals generated in sugar moiety of DNA are shown important in the strand break by recent studies on crystalline DNA irradiated by X-ray, DNA solution by electron and photon beams, hydrated DNA by γ-ray and by high linear energy transfer (LET) ion. Author's pulse radiolysis studies have revealed behaviors of guanine and adenine radical cations in dynamics of DNA oxidation. Since reactions described are the model, the experimental approach is thought necessary for elucidation of the actually occurring DNA damage in living cells. (N.I.)

  1. Radiation Damage Monitoring in the ATLAS Pixel Detector

    CERN Document Server

    Seidel, S

    2013-01-01

    We describe the implementation of radiation damage monitoring using measurement of leakage current in the ATLAS silicon pixel sensors. The dependence of the leakage current upon the integrated luminosity is presented. The measurement of the radiation damage corresponding to integrated luminosity 5.6 fb$^{-1}$ is presented along with a comparison to the theoretical model.

  2. Use of heavy ions to model radiation damage of metals

    International Nuclear Information System (INIS)

    Shirokov, S.V.; Vyshemirskij, M.P.

    2011-01-01

    The methods for modeling radiation damage of metals using heavy ions are reviewed and the results obtained are analyzed. It is shown that irradiation of metals with heavy ion can simulate neutron exposure with the equivalent dose with adequate accuracy and permits a detailed analysis of radiation damage of metals

  3. Constructive and critical approach of the radiation damage simulation

    International Nuclear Information System (INIS)

    Becquart, Ch.

    2002-11-01

    This work deals with the problem of radiation damage in materials for applications in development of fission and nuclear fusion technologies. It is organised in 3 sections. In section 1 are presented the mechanisms of formation and the evolution kinetics of the primary damage. Section 2 is devoted to the study of the sensitivity of the radiation damage at different approximations. Section 3 discusses the contribution of the ab initio calculations to the study of radiation damage and more particularly the point defects in a dilute Fe-Cu ferritic alloy. This work is illustrated by several publications added in each section. (O.M.)

  4. Radiation damage to DNA: the effect of LET

    Energy Technology Data Exchange (ETDEWEB)

    Ward, J F; Milligan, J R [California Univ., San Diego, La Jolla, CA (United States). School of Medicine

    1997-03-01

    Mechanisms whereby ionizing radiation induced damage are introduced into cellular DNA are discussed. The types of lesions induced are summarized and the rationale is presented which supports the statement that radiation induced singly damaged sites are biologically unimportant. The conclusion that multiply damaged sites are critical is discussed and the mechanisms whereby such lesions are formed are presented. Structures of multiply damaged sites are summarized and problems which they present to cellular repair systems are discussed. Lastly the effects of linear energy transfer on the complexity of multiply damaged sites are surveyed and the consequences of this increased complexity are considered in terms of cell survival and mutation. (author)

  5. Biologically important radiation damage in DNA

    International Nuclear Information System (INIS)

    Ward, J.F.

    1994-01-01

    Most DNA damage by the hydroxyl radical is confined to the bases, and this base damage represents an important component of locally multiply demanded sites (LMOS). The yields of the major damaged bases have been determined by gas chromatography mass spectrometry. For our propose, it was necessary to convert a known fraction of these damaged bases to strand breaks and then assay these labile sites as the increase in strand break yield over the normally observed level. Three potential agents by which this strategy of conversion of base damage to strand break could be implemented were identified in the original application: 1, Sl nuclease; 2, piperidine; and 3, base damage specific enzymes

  6. Radiation damage in a high Ni weld

    International Nuclear Information System (INIS)

    Brumovsky, M.; Kytka, M.; Kopriva, R.

    2015-01-01

    WWER-1000 RPV weld metals are characterized by a high content of nickel, mostly about 1.7 mass % with content of manganese around 0.8 mass % with a very low copper content - about 0.05 mass %. In such material some late blooming phase effect should be observed during irradiation. Such typical weld material was irradiated in the experimental reactor LVR-15 in N RI Rez at the irradiation temperature 290 C degrees and at five neutron fluences from 1.5 to 9.5 *10 23 m -2 (E>1 MeV). Charpy V-notch impact tests, static fracture toughness tests, tensile and hardness measurement were performed to obtain effect of neutron fluence on radiation hardening as well as embrittlement. Neutron fluence dependences of all these property changes have monotonic character but with a high neutron embrittlement exponent around 0.8. Scanning electron microscope of fracture surfaces showed no or very small portion of intercrystalline fracture. Transmission electron microscopy was performed on specimens from all neutron fluences. Only low density of black-dot damage has been observed. It is assumed that most of defect are dislocation loops. The late blooming phase which may be observed from results of mechanical properties are probably below the resolution of the used JEM-2010, i.e. 1.5 nm. (authors)

  7. Chemistry of radiation damage to wire chambers

    International Nuclear Information System (INIS)

    Wise, J.

    1992-08-01

    Proportional counters are used to study aspects of radiation damage to wire chambers (wire aging). Principles of low-pressure, rf plasma chemistry are used to predict the plasma chemistry in electron avalanches (1 atm, dc). (1) Aging is studied in CF 4 /iC 4 H 10 gas mixtures. Wire deposits are analyzed by Auger electron spectroscopy. An apparent cathode aging process resulting in loss of gain rather than in a self-sustained current is observed in CF 4 -rich gases. A four-part model considering plasma polymerization of the hydrocarbon, etching of wire deposits by CF 4 , acceleration of deposition processes in strongly etching environments, and reactivity of the wire surface is developed to understand anode wire aging in CF 4 /iC 4 H 10 gases. Practical guidelines suggested by the model are discussed. (2) Data are presented to suggest that trace amounts of Freons do not affect aging rates in either dimethyl ether or Ar/C 2 H 6 . Apparent loss of gain is explained by attachment of primary electrons to a continuously increasing concentration of Freon 11 (CCl 3 F) in the counter gas. An increase in the concentration of Freon 11 in dimethyl ether is caused by a distillation process in the gas supply bottle and is a natural consequence of the unequal volatilities of the two compounds

  8. Radiation damage in flash memory cells

    International Nuclear Information System (INIS)

    Claeys, C.; Ohyama, H.; Simoen, E.; Nakabayashi, M.; Kobayashi, K.

    2002-01-01

    Results are presented of a study on the effects of total ionization dose and displacement damage, induced by high-energy electrons, protons and alphas, on the performance degradation of flash memory cells integrated in a microcomputer. A conventional stacked-gate n-channel flash memory cell using a 0.8 μm n-polysilicon gate technology is employed. Irradiations by 1-MeV electrons and 20-MeV protons and alpha particles were done at room temperature. The impact of the fluence on the input characteristics, threshold voltage shift and drain and gate leakage was investigated. The threshold voltage change for proton and alpha irradiations is about three orders of magnitude larger than that for electrons. The performance degradation is mainly caused by the total ionization dose (TID) damage in the tunnel oxide and in the interpoly dielectric layer and by the creation of interface traps at the Si-SiO 2 interface. The impact of the irradiation temperature on the device degradation was studied for electrons and gammas, pointing out that irradiation at room temperature is mostly the worst case. Finally, attention is given to the impact of isochronal and isothermal annealing on the recovery of the degradation introduced after room temperature proton and electron irradiation

  9. Radiation damage measurements in room temperature semiconductor radiation detectors

    International Nuclear Information System (INIS)

    Franks, L.A.; Olsen, R.W.; James, R.B.; Brunett, B.A.; Walsh, D.S.; Doyle, B.L.; Vizkelethy, G.; Trombka, J.I.

    1998-01-01

    The literature of radiation damage measurements on cadmium zinc telluride (CZT), cadmium telluride (CT), and mercuric iodide (HgI 2 ) is reviewed and in the case of CZT supplemented by new alpha particle data. CZT strip detectors exposed to intermediate energy (1.3 MeV) proton fluences exhibit increased interstrip leakage after 10 10 p/cm 2 and significant bulk leakage after 10 12 p/cm 2 . CZT exposed to 200 MeV protons shows a two-fold loss in energy resolution after a fluence of 5 x 10 9 p/cm 2 in thick (3 mm) planar devices but little effect in 2 mm devices. No energy resolution effects were noted from moderated fission spectrum of neutrons after fluences up to 10 10 n/cm 2 , although activation was evident. Exposures of CZT to 5 MeV alpha particle at fluences up to 1.5 x 10 10 α/cm 2 produced a near linear decrease in peak position with fluence and increases in FWHM beginning at about 7.5 x 10 9 α/cm 2 . CT detectors show resolution losses after fluences of 3 x 10 9 p/cm 2 at 33 MeV for chlorine-doped detectors. Indium doped material may be more resistant. Neutron exposures (8 MeV) caused resolution losses after fluences of 2 x 10 10 n/cm 2 . Mercuric iodide has been studied with intermediate energy protons (10 to 33 MeV) at fluences up to 10 12 p/cm 2 and with 1.5 GeV protons at fluences up to 1.2 x 10 8 p/cm 2 . Neutron exposures at 8 MeV have been reported at fluences up to 10 15 n/cm 2 . No radiation damage was reported under these irradiation conditions

  10. Radiation damage and its repair in non-sporulating bacteria

    International Nuclear Information System (INIS)

    Moseley, B.E.B.

    1984-01-01

    A review is given of radiation damage and its repair in non-sporulating bacteria. The identification and measurement of radiation damage in the DNA of the bacteria after exposure to ultraviolet radiation and ionizing radiation is described. Measuring the extent of DNA repair and ways of isolating repair mutants are also described. The DNA repair mechanisms for UV-induced damage are discussed including photoreactivation repair, excision repair, post-replication recombination repair and induced error-prone repair. The DNA repair mechanisms for ionizing radiation damage are also discussed including the repair of both single and double-strand breaks. Other aspects discussed include the effects of growth, irradiation medium and recovery medium on survival, DNA repair in humans, the commercial use of UV and ionizing radiations and the future of ionizing irradiation as a food treatment process. (U.K.)

  11. Delayed damage after radiation therapy for head and neck cancer

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Yoshiyuki [Osaka Dental Univ., Hirakata (Japan)

    2000-03-01

    I investigated radiation damage, including osteoradionecrosis, arising from tooth extraction in fields that had received radiation therapy for head and neck cancer, and evaluated the effectiveness of pilocarpine for xerostomia. Between January 1990 and April 1996, I examined 30 patients for bone changes after tooth extraction in fields irradiated at the Department of Oral Radiology, Osaka Dental University Hospital. Nineteen of the patients had been treated for nasopharyngeal cancer and 11 for oropharyngeal cancer. Between January and April 1996, 4 additional patients were given pilocarpine hydrochloride (3-mg, 6-mg and 9-mg of KSS-694 orally three times a day) for 12 weeks and evaluated every 4 weeks as a base line. One had been treated for nasopharyngeal carcinoma, two for cancer of the cheek and one for an unknown carcinoma. Eighteen of the patients (11 with nasopharyngeal carcinoma and 7 with oropharyngeal carcinoma) had extractions. Use of preoperative and postoperative radiographs indicated that damage to the bone following tooth extraction after radiation exposure was related to whether antibiotics were administered the day before the extraction, whether forceps or elevators were used, and whether the tooth was in the field of radiation. Xerostomia improved in all 4 of the patients who received 6-mg or 9-mg of pilocarpine. It improved saliva production and relieved the symptoms of xerostomia after radiation therapy for head and neck cancer, although there were minor side effects such as fever. This information can be used to improve the oral environment of patients who have received radiation therapy for head and neck cancer, and to better understand their oral environment. (author)

  12. Delayed damage after radiation therapy for head and neck cancer

    International Nuclear Information System (INIS)

    Matsumoto, Yoshiyuki

    2000-01-01

    I investigated radiation damage, including osteoradionecrosis, arising from tooth extraction in fields that had received radiation therapy for head and neck cancer, and evaluated the effectiveness of pilocarpine for xerostomia. Between January 1990 and April 1996, I examined 30 patients for bone changes after tooth extraction in fields irradiated at the Department of Oral Radiology, Osaka Dental University Hospital. Nineteen of the patients had been treated for nasopharyngeal cancer and 11 for oropharyngeal cancer. Between January and April 1996, 4 additional patients were given pilocarpine hydrochloride (3-mg, 6-mg and 9-mg of KSS-694 orally three times a day) for 12 weeks and evaluated every 4 weeks as a base line. One had been treated for nasopharyngeal carcinoma, two for cancer of the cheek and one for an unknown carcinoma. Eighteen of the patients (11 with nasopharyngeal carcinoma and 7 with oropharyngeal carcinoma) had extractions. Use of preoperative and postoperative radiographs indicated that damage to the bone following tooth extraction after radiation exposure was related to whether antibiotics were administered the day before the extraction, whether forceps or elevators were used, and whether the tooth was in the field of radiation. Xerostomia improved in all 4 of the patients who received 6-mg or 9-mg of pilocarpine. It improved saliva production and relieved the symptoms of xerostomia after radiation therapy for head and neck cancer, although there were minor side effects such as fever. This information can be used to improve the oral environment of patients who have received radiation therapy for head and neck cancer, and to better understand their oral environment. (author)

  13. Heavy ion linear accelerator for radiation damage studies of materials

    Energy Technology Data Exchange (ETDEWEB)

    Kutsaev, Sergey V.; Mustapha, Brahim; Ostroumov, Peter N.; Nolen, Jerry; Barcikowski, Albert; Pellin, Michael; Yacout, Abdellatif

    2017-03-01

    A new eXtreme MATerial (XMAT) research facility is being proposed at Argonne National Laboratory to enable rapid in situ mesoscale bulk analysis of ion radiation damage in advanced materials and nuclear fuels. This facility combines a new heavy-ion accelerator with the existing high-energy X-ray analysis capability of the Argonne Advanced Photon Source. The heavy-ion accelerator and target complex will enable experimenters to emulate the environment of a nuclear reactor making possible the study of fission fragment damage in materials. Material scientists will be able to use the measured material parameters to validate computer simulation codes and extrapolate the response of the material in a nuclear reactor environment. Utilizing a new heavy-ion accelerator will provide the appropriate energies and intensities to study these effects with beam intensities which allow experiments to run over hours or days instead of years. The XMAT facility will use a CW heavy-ion accelerator capable of providing beams of any stable isotope with adjustable energy up to 1.2 MeV/u for U-238(50+) and 1.7 MeV for protons. This energy is crucial to the design since it well mimics fission fragments that provide the major portion of the damage in nuclear fuels. The energy also allows damage to be created far from the surface of the material allowing bulk radiation damage effects to be investigated. The XMAT ion linac includes an electron cyclotron resonance ion source, a normal-conducting radio-frequency quadrupole and four normal-conducting multi-gap quarter-wave resonators operating at 60.625 MHz. This paper presents the 3D multi-physics design and analysis of the accelerating structures and beam dynamics studies of the linac.

  14. Heavy ion linear accelerator for radiation damage studies of materials.

    Science.gov (United States)

    Kutsaev, Sergey V; Mustapha, Brahim; Ostroumov, Peter N; Nolen, Jerry; Barcikowski, Albert; Pellin, Michael; Yacout, Abdellatif

    2017-03-01

    A new eXtreme MATerial (XMAT) research facility is being proposed at Argonne National Laboratory to enable rapid in situ mesoscale bulk analysis of ion radiation damage in advanced materials and nuclear fuels. This facility combines a new heavy-ion accelerator with the existing high-energy X-ray analysis capability of the Argonne Advanced Photon Source. The heavy-ion accelerator and target complex will enable experimenters to emulate the environment of a nuclear reactor making possible the study of fission fragment damage in materials. Material scientists will be able to use the measured material parameters to validate computer simulation codes and extrapolate the response of the material in a nuclear reactor environment. Utilizing a new heavy-ion accelerator will provide the appropriate energies and intensities to study these effects with beam intensities which allow experiments to run over hours or days instead of years. The XMAT facility will use a CW heavy-ion accelerator capable of providing beams of any stable isotope with adjustable energy up to 1.2 MeV/u for 238 U 50+ and 1.7 MeV for protons. This energy is crucial to the design since it well mimics fission fragments that provide the major portion of the damage in nuclear fuels. The energy also allows damage to be created far from the surface of the material allowing bulk radiation damage effects to be investigated. The XMAT ion linac includes an electron cyclotron resonance ion source, a normal-conducting radio-frequency quadrupole and four normal-conducting multi-gap quarter-wave resonators operating at 60.625 MHz. This paper presents the 3D multi-physics design and analysis of the accelerating structures and beam dynamics studies of the linac.

  15. Effects of radiation damage on the silicon lattice

    Science.gov (United States)

    Dumas, Katherine A.; Lowry, Lynn; Russo, O. Louis

    1987-01-01

    Silicon was irradiated with both proton and electron particle beams in order to investigate changes in the structural and optical properties of the lattice as a result of the radiation damage. Lattice expansions occurred when large strain fields (+0.34 percent) developed after 1- and 3-MeV proton bombardment. The strain was a factor of three less after 1-MeV electron irradiation. Average increases of approximately 22 meV in the 3.46-eV interband energy gap and 14 meV in the Lorentz broadening parameter were measured after the electron irradiation.

  16. Progress on clustered DNA damage in radiation research

    International Nuclear Information System (INIS)

    Yang Li'na; Zhang Hong; Di Cuixia; Zhang Qiuning; Wang Xiaohu

    2012-01-01

    Clustered DNA damage which caused by high LET heavy ion radiation can lead to mutation, tumorigenesis and apoptosis. Promoting apoptosis of cancer cells is always the basis of cancer treatment. Clustered DNA damage has been the hot topic in radiobiology. The detect method is diversity, but there is not a detail and complete protocol to analyze clustered DNA damage. In order to provide reference for clustered DNA damage in the radiotherapy study, the clustered DNA damage characteristics, the latest progresses on clustered DNA damage and the detecting methods are reviewed and discussed in detail in this paper. (authors)

  17. Radiation damage in silicon exposed to high-energy protons

    International Nuclear Information System (INIS)

    Davies, Gordon; Hayama, Shusaku; Murin, Leonid; Krause-Rehberg, Reinhard; Bondarenko, Vladimir; Sengupta, Asmita; Davia, Cinzia; Karpenko, Anna

    2006-01-01

    Photoluminescence, infrared absorption, positron annihilation, and deep-level transient spectroscopy (DLTS) have been used to investigate the radiation damage produced by 24 GeV/c protons in crystalline silicon. The irradiation doses and the concentrations of carbon and oxygen in the samples have been chosen to monitor the mobility of the damage products. Single vacancies (and self-interstitials) are introduced at the rate of ∼1 cm -1 , and divacancies at 0.5 cm -1 . Stable di-interstitials are formed when two self-interstitials are displaced in one damage event, and they are mobile at room temperature. In the initial stages of annealing the evolution of the point defects can be understood mainly in terms of trapping at the impurities. However, the positron signal shows that about two orders of magnitude more vacancies are produced by the protons than are detected in the point defects. Damage clusters exist, and are largely removed by annealing at 700 to 800 K, when there is an associated loss of broad band emission between 850 and 1000 meV. The well-known W center is generated by restructuring within clusters, with a range of activation energies of about 1.3 to 1.6 eV, reflecting the disordered nature of the clusters. Comparison of the formation of the X centers in oxygenated and oxygen-lean samples suggests that the J defect may be interstitial related rather than vacancy related. To a large extent, the damage and annealing behavior may be factorized into point defects (monitored by sharp-line optical spectra and DLTS) and cluster defects (monitored by positron annihilation and broadband luminescence). Taking this view to the limit, the generation rates for the point defects are as predicted by simply taking the damage generated by the Coulomb interaction of the protons and Si nuclei

  18. Radiation damage monitoring in the ATLAS pixel detector

    International Nuclear Information System (INIS)

    Seidel, Sally

    2013-01-01

    We describe the implementation of radiation damage monitoring using measurement of leakage current in the ATLAS silicon pixel sensors. The dependence of the leakage current upon the integrated luminosity is presented. The measurement of the radiation damage corresponding to an integrated luminosity 5.6 fb −1 is presented along with a comparison to a model. -- Highlights: ► Radiation damage monitoring via silicon leakage current is implemented in the ATLAS (LHC) pixel detector. ► Leakage currents measured are consistent with the Hamburg/Dortmund model. ► This information can be used to validate the ATLAS simulation model.

  19. Fundamental Technology Development for Radiation Damage in Nuclear Materials

    International Nuclear Information System (INIS)

    Kwon, Sang Chul; Kwon, J. H.; Kim, E. S. and others

    2005-04-01

    This project was performed to achieve technologies for the evaluation of radiation effects at materials irradiated at HANARO and nuclear power plants, to establish measurement equipment and software for the analysis of radiation defects and to set up facilities for the measurements of radiation damage with non-destructive methods. Major targets were 1) establishment of hot laboratories and remote handling facilities/ technologies for the radioactive material tests, 2) irradiation test for the simulation of nuclear power plant environment and measurement/calculation of physical radiation damage, 3) evaluation and analysis of nano-scale radiation damage, 4) evaluation of radiation embrittlement with ultrasonic resonance spectrum measurement and electromagnetic measurement and 5) basic research of radiation embrittlement and radiation damage mechanism. Through the performance of 3 years, preliminary basics were established for the application research to evaluation of irradiated materials of present nuclear power plants and GEN-IV systems. Particularly the results of SANS, PAS and TEM analyses were the first output in Korea. And computer simulations of radiation damage were tried for the first time in Korea. The technologies will be developed for the design of GEN-IV material

  20. Photobiological aspects of radiation damage to bacteria

    International Nuclear Information System (INIS)

    Myasnik, M.N.; Skvortsov, V.G.; Sokolov, V.A.

    1981-01-01

    In this report, we, submit a critical analysis of experiments aimed to estimate the contribution of the processes of ionization and electron excitation to lethal and mutagenic effects of ionizing radiation. In discussing the phenomenon of photoreactivation after the effect of ionizing radiation, we arrived at a conclusion that the processes of electron excitation, initiated by either Vavilov-Cerenkov light or the direct reaction of radiation energy with the substance, play an important role in the biological effect of ionizing radiation [ru

  1. Radiation damage on sub-cellular scales: beyond DNA

    International Nuclear Information System (INIS)

    Byrne, H L; McNamara, A L; Domanova, W; Kuncic, Z; Guatelli, S

    2013-01-01

    This study investigates a model cell as a target for low-dose radiation using Monte Carlo simulations. Mono-energetic electrons and photons are used with initial energies between 10 and 50 keV, relevant to out-of-field radiotherapy scenarios where modern treatment modalities expose relatively large amounts of healthy tissue to low-dose radiation, and also to microbeam cell irradiation studies which show the importance of the cytoplasm as a radiation target. The relative proportions of number of ionizations and total energy deposit in the nucleus and cytoplasm are calculated. We show that for a macroscopic dose of no more than 1 Gy only a few hundred ionizations occur in the nucleus volume whereas the number of ionizations in the cytoplasm is over a magnitude larger. We find that the cell geometry can have an appreciable effect on the energy deposit in the cell and can cause a nonlinear increase in energy deposit with cytoplasm density. We also show that changing the nucleus volume has negligible effect on the total energy deposit but alters the relative proportion deposited in the nucleus and cytoplasm; the nucleus volume must increase to approximately the same volume as the cytoplasm before the energy deposit in the nucleus matches that in the cytoplasm. Additionally we find that energy deposited by electrons is generally insensitive to spatial variations in chemical composition, which can be attributed to negligible differences in electron stopping power for cytoplasm and nucleus materials. On the other hand, we find that chemical composition can affect energy deposited by photons due to non-negligible differences in attenuation coefficients. These results are of relevance in considering radiation effects in healthy cells, which tend to have smaller nuclei. Our results further show that the cytoplasm and organelles residing therein can be important targets for low-dose radiation damage in healthy cells and warrant investigation as much as the conventional focus

  2. DNA Damage by Radiation in Tradescantia Leaf Cells

    International Nuclear Information System (INIS)

    Han, Min; Hyun, Kyung Man; Ryu, Tae Ho; Kim, Jin Kyu; Nili, Mohammad

    2010-01-01

    The comet assay is currently used in different areas of biological sciences to detect DNA damage. The comet assay, due to its simplicity, sensitivity and need of a few cells, is ideal as a short-term genotoxicity test. The comet assay can theoretically be applied to every type of eukaryotic cell, including plant cells. Plants are very useful as monitors of genetic effects caused by pollution in the atmosphere, water and soil. Tradescantia tests are very useful tools for screening the mutagenic potential in the environment. Experiments were conducted to study the genotoxic effects of ionizing radiations on the genome integrity, particularly of Tradescantia. The increasingly frequent use of Tradescantia as a sensitive environmental bioindicator of genotoxic effects. This study was designed to assess the genotoxicity of ionizing radiation using Tradescnatia-comet assay. The development of comet assay has enabled investigators to detect DNA damage at the levels of cells. To adapt this assay to plant cells, nuclei were directly obtained from Tradescantia leaf samples. A significant dose-dependent increase in the average tail moment values over the negative control was observed. Recently the adaptation of this technique to plant cells opens new possibilities for studies in variety area. The future applications of the comet assay could impact some other important areas, certainly, one of the limiting factors to its utility is the imagination of the investigator.

  3. DNA Damage by Radiation in Tradescantia Leaf Cells

    Energy Technology Data Exchange (ETDEWEB)

    Han, Min; Hyun, Kyung Man; Ryu, Tae Ho; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Advanced Radiation Technology Institute, Jeongeup (Korea, Republic of); Nili, Mohammad [Dawnesh Radiation Research Institute, Barcelona (Spain)

    2010-04-15

    The comet assay is currently used in different areas of biological sciences to detect DNA damage. The comet assay, due to its simplicity, sensitivity and need of a few cells, is ideal as a short-term genotoxicity test. The comet assay can theoretically be applied to every type of eukaryotic cell, including plant cells. Plants are very useful as monitors of genetic effects caused by pollution in the atmosphere, water and soil. Tradescantia tests are very useful tools for screening the mutagenic potential in the environment. Experiments were conducted to study the genotoxic effects of ionizing radiations on the genome integrity, particularly of Tradescantia. The increasingly frequent use of Tradescantia as a sensitive environmental bioindicator of genotoxic effects. This study was designed to assess the genotoxicity of ionizing radiation using Tradescnatia-comet assay. The development of comet assay has enabled investigators to detect DNA damage at the levels of cells. To adapt this assay to plant cells, nuclei were directly obtained from Tradescantia leaf samples. A significant dose-dependent increase in the average tail moment values over the negative control was observed. Recently the adaptation of this technique to plant cells opens new possibilities for studies in variety area. The future applications of the comet assay could impact some other important areas, certainly, one of the limiting factors to its utility is the imagination of the investigator.

  4. Current study on ionizing radiation-induced mitochondial DNA damage and mutations

    International Nuclear Information System (INIS)

    Zhou Xin; Wang Zhenhua; Zhang Hong

    2012-01-01

    Current advance in ionizing radiation-induced mitochondrial DNA damage and mutations is reviewed, in addition with the essential differences between mtDNA and nDNA damage and mutations. To extent the knowledge about radiation induced mitochondrial alterations, the researchers in Institute of Modern Physics, Chinese Academy of Sciences developed some technics such as real-time PCR, long-PCR for accurate quantification of radiation induced damage and mutations, and in-depth investigation about the functional changes of mitochondria based on mtDNA damage and mutations were also carried out. In conclusion, the important role of mitochondrial study in radiation biology is underlined, and further study on mitochondrial study associated with late effect and metabolism changes in radiation biology is pointed out. (authors)

  5. Radiation damage measurements in room-temperature semiconductor radiation detectors

    CERN Document Server

    Franks, L A; Olsen, R W; Walsh, D S; Vizkelethy, G; Trombka, J I; Doyle, B L; James, R B

    1999-01-01

    The literature of radiation damage measurements on cadmium zinc telluride (CZT), cadmium telluride (CT), and mercuric iodide (HgI sub 2) is reviewed and in the case of CZT supplemented by new alpha particle data. CZT strip detectors exposed to intermediate energy (1.3 MeV) proton fluences exhibit increased interstrip leakage after 10 sup 1 sup 0 p/cm sup 2 and significant bulk leakage after 10 sup 1 sup 2 p/cm sup 2. CZT exposed to 200 MeV protons shows a two-fold loss in energy resolution after a fluence of 5x10 sup 9 p/cm sup 2 in thick (3 mm) planar devices but little effect in 2 mm devices. No energy resolution effects were noted from a moderated fission spectrum of neutrons after fluences up to 10 sup 1 sup 0 n/cm sup 2 , although activation was evident. Exposures of CZT to 5 MeV alpha particles at fluences up to 1.5x10 sup 1 sup 0 alpha/cm sup 2 produced a near linear decrease in peak position with fluence and increases in FWHM beginning at about 7.5x10 sup 9 alpha/cm sup 2. CT detectors show resolution...

  6. Activation and radiation damage in the environment of hadron accelerators

    CERN Document Server

    Kiselev, Daniela

    2013-01-01

    A component which suffers radiation damage usually also becomes radioactive, since the source of activation and radiation damage is the interaction of the material with particles from an accelerator or with reaction products. However, the underlying mechanisms of the two phenomena are different. These mechanisms are described here. Activation and radiation damage can have far-reaching consequences. Components such as targets, collimators, and beam dumps are the first candidates for failure as a result of radiation damage. This means that they have to be replaced or repaired. This takes time, during which personnel accumulate dose. If the dose to personnel at work would exceed permitted limits, remote handling becomes necessary. The remaining material has to be disposed of as radioactive waste, for which an elaborate procedure acceptable to the authorities is required. One of the requirements of the authorities is a complete nuclide inventory. The methods used for calculation of such inventories are presented,...

  7. High LET radiation and mechanism of DNA damage repair

    International Nuclear Information System (INIS)

    Furusawa, Yoshiya

    2004-01-01

    Clarifying the mechanism of repair from radiation damage gives most important information on radiation effects on cells. Approximately 10% of biological experiments groups in Heavy Ion Medical Accelerator in Chiba (HIMAC) cooperative research group has performed the subject. They gave a lot of new findings on the mechanism, and solved some open questions. The reason to show the peak of relative biological effectiveness RBE at around 100-200 keV/μm causes miss-repair of DNA damage. Sub-lethal damage generated by high linear energy transfer (LET) radiation can be repaired fully. Potentially lethal damages by high-LET radiation also repaired, but the efficiency decreased with the LET, and so on. (author)

  8. Positron annihilation and perturbed angular correlation studies of radiation damage

    International Nuclear Information System (INIS)

    Zhu Jiazheng; Li Anli; Xu Yongjun; Wang Zhiqiang; Zhou Dongmei; Zheng Yongnan; Zhu Shengyun; Iwata, T.

    2002-01-01

    The positron annihilation and perturbed angular correlation techniques have been employed to study radiation damage in Si and Nb. The results obtained by the positron annihilation are consistent with those given by the perturbed angular correlation

  9. Single Molecule Scanning of DNA Radiation Oxidative Damage, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal will develop an assay to map genomic DNA, at the single molecule level and in a nanodevice, for oxidative DNA damage arising from radiation exposure;...

  10. Radiation damage to the brain: neuropsychiatric aspects

    International Nuclear Information System (INIS)

    McMahon, T.; Vahora, S.

    1986-01-01

    Although radiation necrosis of the brain is a recognized complication of irradiation of the central nervous system, the psychiatric aspects of this phenomenon are less well defined. Two cases of radiation necrosis in which psychiatric symptoms were a prominent part of the clinical picture are presented. Factors that determine the evolution and clinical presentation of radiation necrosis are reviewed. In particular, the role of the consultation psychiatrist in the diagnosis and management of such patients is discussed

  11. Automated analysis of damages for radiation in plastics surfaces

    International Nuclear Information System (INIS)

    Andrade, C.; Camacho M, E.; Tavera, L.; Balcazar, M.

    1990-02-01

    Analysis of damages done by the radiation in a polymer characterized by optic properties of polished surfaces, of uniformity and chemical resistance that the acrylic; resistant until the 150 centigrade grades of temperature, and with an approximate weight of half of the glass. An objective of this work is the development of a method that analyze in automated form the superficial damages induced by radiation in plastic materials means an images analyst. (Author)

  12. Macroscopic morphology of radiation damage in copper

    International Nuclear Information System (INIS)

    Black, K.E.

    1977-01-01

    This Thesis describes the damage produced in copper single crystals when they are irradiated with neutrons from a nuclear reactor, and shows that the morphology of the damage is dependent on the temperature of irradiation. The production of point defects in the initial stages of the bombardment and their subsequent diffusion is described in Chapter One. Chapter Two describes the techniques used to etch and thus make visible the damage regions. The defect clusters were examined with a microscope. A typical selection of micrographs of the damage is presented and discussed in Chapter Three. In the final chapter, Chapter Four, the results of the present work are discussed in the light of work done by other research workers. The Thesis ends with a brief suggestion for future work to be carried out on neutron irradiated copper single crystals

  13. Radio-oxidative membrane damage and its possible role as an indicator of radiation exposure

    International Nuclear Information System (INIS)

    Amit Kumar; Pandey, B.N.; Mishra, K.P.

    2004-01-01

    Cellular membranes have been recognized as a sensitive target in the mechanism of ionizing radiation-induced cell killing. In our laboratory, studies have been devoted to investigations on gamma radiation induced oxidative damage to model and cellular membrane damage by employing fluorescence and electron spin resonance (ESR) methods Considerable evidences has accumulated to suggest that radiation induced oxidative damage was related to apoptotic death of a variety of cells in culture. Radiation induced damage involving lipid peroxidation, altered bilayer fluidity, permeability changes and intracellular generated ROS have been evaluated by chemical and physical methods. Modification of damage by structural modulating agents such as cholesterol and antioxidants such as eugenol, ascorbic acid, ellagic acid, triphala have been extensively investigated. Generation of intracellular ROS in radiation stressed normal cell e.g. mouse thymocytes, tumor cells e.g. Ehrlich ascites cells and human cervical cell line were evaluated after exposure from low to moderate doses of α-radiation. Results suggest that modulation of intracellular ROS level may be an important approach to alter radio-cytotoxicity of cells. This presentation would describe results of our study together with an overview of free radical mediated oxidative damage to cellular membrane as an indicator of radiation exposure. (author)

  14. Radiation damage to DNA: The importance of track structure

    CERN Document Server

    Hill, M A

    1999-01-01

    A wide variety of biological effects are induced by ionizing radiation, from cell death to mutations and carcinogenesis. The biological effectiveness is found to vary not only with the absorbed dose but also with the type of radiation and its energy, i.e., with the nature of radiation tracks. An overview is presented of some of the biological experiments using different qualities of radiation, which when compared with Monte Carlo track structure studies, have highlighted the importance of the localized spatial properties of stochastic energy deposition on the nanometer scale at or near DNA. The track structure leads to clustering of damage which may include DNA breaks, base damage etc., the complexity of the cluster and therefore its biological repairability varying with radiation type. The ability of individual tracks to produce clustered damage, and the subsequent biological response are important in the assessment of the risk associated with low-level human exposure. Recent experiments have also shown that...

  15. A review on radiation damage of erythrocyte membranes

    International Nuclear Information System (INIS)

    Wang Junling; Wang Weidong; Qin Guangyong

    2007-01-01

    Biomembrane has very important biological function. Its damage will seriously disturb the directivity, the orderly nature and coordination of cell metabolism, and finally causes the cell death. This paper reviewed the effects of radiation damage on erythrocyte membrane in membrane composition, membrane function and oxidation resistance system. (authors)

  16. Radiation-induced brain damage in children

    International Nuclear Information System (INIS)

    Oi, Shizuo; Kokunai, Takashi; Ijichi, Akihiro; Matsumoto, Satoshi; Raimondi, A.J.

    1990-01-01

    The nature and sequence of the radiation-induced changes in the brain were studied postmortem in 34 children with glioma, 22 of whom underwent central nervous system radiation therapy. Twenty received whole-brain or whole-neuroaxis radiation at a total mean dosage of 4063 cGy. Brain tissue alternations were analyzed histologically by means of various staining methods, including immunohistochemical techniques. The histological features of irradiated brains were compared with those of non-irradiated brains. Microscopic findings included demyelination (seven cases), focal necrosis (six cases), cortical atrophy (four cases), endothelial proliferation (four cases), and telangiectatic vascular proliferation with vascular thickening and oozing of a thick fluid (one case). Such findings were rare in non-irradiated patients. Demyelination was observed earliest in a patient who died 5 months after radiation therapy and was more common after 9 months. Focal necrosis was first observed 9 months post-irradiation but was more advanced and extensive after 1 year. Calcified foci were found only after 60 months. Various vascular changes such as vascular thickening and thrombosis suggested ischemic insult to the brain as a late effect of radiation injury. The results of this study suggest that the immature brain may be more sensitive to radiation than is the adult brain, and that the manifestations of radiation-induced injury depend on the time elapsed after irradiation. (author)

  17. Chemical aspects of radiation damage processes: radiolysis

    International Nuclear Information System (INIS)

    Asmus, K.D.

    1975-01-01

    The formation of primary species and radiation chemical yields are discussed. In a section on chemical scavenging of primary species the author considers scavenging kinetics and competition reactions and gives a brief outline of some experimental methods. The radiation chemistry of aqueous solutions is discussed as an example for polar solvents. Cyclohexane is used as an example for non-polar solvents. The importance of excited states and energy transfer is considered. Reactions in the solid state are discussed and results on linear energy transfer and average ion pair formation for various kinds of radiation are surveyed. (B.R.H.)

  18. Radiation damage in molybdenum and tungsten in high neutron fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Veljkovic, S; Milasin, N [Institute of Nuclear Sciences Boris Kidric, Department of Reactor Materials, Vinca, Beograd (Serbia and Montenegro)

    1964-04-15

    The effects of radiation on molybdenum and tungsten in high neutron fluxes are presented. The changes induced, particularly defects with a high migration activation energy, are analyzed. The correlation of these changes with the basic concepts of radiation damage in solids is considered. An attempt is made to relate the defects studied with the changes in macroscopic properties (author)

  19. Early mechanisms in radiation-induced biological damage

    International Nuclear Information System (INIS)

    Powers, E.L.

    1983-01-01

    An introduction to the mechanisms of radiation action in biological systems is presented. Several questions about the nature of the radiation damage process are discussed, including recognition of the oxygen effects, dose-response relationships, and the importance of the hydroxyl radical

  20. Radiation damage in molybdenum and tungsten in high neutron fluxes

    International Nuclear Information System (INIS)

    Veljkovic, S.; Milasin, N.

    1964-01-01

    The effects of radiation on molybdenum and tungsten in high neutron fluxes are presented. The changes induced, particularly defects with a high migration activation energy, are analyzed. The correlation of these changes with the basic concepts of radiation damage in solids is considered. An attempt is made to relate the defects studied with the changes in macroscopic properties (author)

  1. Issues of damage estimation under radiation emergency situation

    International Nuclear Information System (INIS)

    Volobuev, P.V.; Kozlova, N.I.

    2005-01-01

    The specificity of social, economical and ecological consequences of major radiation emergency situation is considered in the paper. The definitions and structure of direct and indirect damage under radiation emergency situation are given. The priority components of immediate expenses and those of long-term living on the contaminated territories are considered in the paper. (author)

  2. Radiation damage calculations for compound materials

    International Nuclear Information System (INIS)

    Greenwood, L.R.

    1990-01-01

    This paper reports on the SPECOMP computer code, developed to calculate neutron-induced displacement damage cross sections for compound materials such as alloys, insulators, and ceramic tritium breeders for fusion reactors. These new calculations rely on recoil atom energy distributions previously computed with the DISCS computer code, the results of which are stored in SPECTER computer code master libraries. All reaction channels were considered in the DISCS calculations and the neutron cross sections were taken from ENDF/B-V. Compound damage calculations with SPECOMP thus do not need to perform any recoil atom calculations and consequently need no access to ENDF or other neutron data bases. The calculations proceed by determining secondary displacements for each combination of recoil atom and matrix atom using the Lindhard partition of the recoil energy to establish the damage energy

  3. Radiation damage calculations for compound materials

    International Nuclear Information System (INIS)

    Greenwood, L.R.

    1989-01-01

    Displacement damage calculations can be performed for 40 elements in the energy range up to 20 MeV with the SPECTER computer code. A recent addition to the code, called SPECOMP, can intermix atomic recoil energy distributions for any four elements to calculate the proper displacement damage for compound materials. The calculations take advantage of the atomic recoil data in the SPECTER libraries, which were determined by the DISCS computer code, using evaluated neutron cross section and angular distribution data in ENDF/B-V. Resultant damage cross sections for any compound can be added to the SPECTER libraries for the routine calculation of displacements in any given neutron field. Users do not require access to neutron cross section files. Results are presented for a variety of fusion materials and a new ceramic superconductor material. Future plans and nuclear data needs are discussed. 11 refs., 6 figs., 1 tab

  4. Investigation of radiation damage in lead

    International Nuclear Information System (INIS)

    Boehm, R.; Christiansen, J.; Hammer, E.; Heubes, P.; Keitel, R.; Klinger, W.; Loeffler, W.; Sandner, W.; Schatz, G.; Schultheiss, C.

    1977-01-01

    The experiments have been carried out on the Hamburg university cyclotron. The 8 + level of 210 Pb (T 1 / 2 = 112 nsec) populated via the 208 Pb (α,2n) 210 Po reaction at an injection energy of Esub(α) = 27 MeV was used for the measurements. The external magnetic field had a strength of 1.3 T; the target temperature was varied between 100 K and 530 K. (WL) [de

  5. Relation of radiation damage of metallic solids to electronic structure. Pt. 5

    International Nuclear Information System (INIS)

    Shalaev, A.M.; Adamenko, A.A.

    1977-01-01

    The problem of relating a damage in metal solids to the parameters of radiation fluxes and the physical nature of a target is considered. Basing upon experimental and theoretical investigations into the processes of interaction of particle fluxes with solids, the following conclusions have been reached. Threshold energy of ion displacement in the crystal lattice of a metal solid is dependent on the energy of a bombarding particle, which is due to ionization and electroexcitation stimulated by energy transfer from a fast particle to a system of collectivized electrons. The rate of metal solid damage by radiation depends on the state of the crystal lattice, in particular on its defectness. Variations of local electron density in the vicinity of a defect are related with changing thermodynamic characteristics of radiation-induced defect formation. A type of atomic bond in a solid affects the rate of radiation damage. The greatest damage occurs in materials with a covalent bond

  6. Properties and recrystallization of radiation damaged pyrochlore and titanite

    Energy Technology Data Exchange (ETDEWEB)

    Zietlow, Peter

    2016-11-02

    Radiation damage in minerals is caused by the alpha-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400-1400 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG) (Zietlow et al., in print). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia (6.4 wt% Th, 23.1.10{sup 18} a-decay events per gram (dpg)), Zlatoust/Russia (6.3 wt% Th, 23.1.10{sup 18} dpg), Panda Hill/Tanzania (1.6 wt% Th, 1.6.10{sup 18} dpg), and Blue River/Canada (10.5 wt% U, 115.4.10{sup 18} dpg), are compared with a crystalline reference pyrochlore from Schelingen (Germany). The type of structural recovery depends on the initial degree of radiation damage (Panda Hill 28 %, Blue River 85 %, Zlatoust and Miass 100 % according to XRD), as the recrystallization temperature increases with increasing degree of amorphization. Raman spectra indicate reordering on the local scale during annealing-induced recrystallization. As Raman modes around 800 cm{sup -1} are sensitive to radiation damage (Vandenborre and Husson 1983, Moll et al. 2011), the degree of local order was deduced from the ratio of the integrated intensities of the sum of the Raman bands between 605 and 680 cm{sup -1} devided by the sum of the integrated intensities of the bands between 810 and 860 cm{sup -1}. The most radiation damaged pyrochlores (Miass and Zlatoust) show an abrupt recovery of both, its short- (Raman) and long-range order (X-ray) between 800 and 850 K. The volume decrease upon recrystallization in Zlatoust pyrochlore was large enough to crack the sample repeatedly. In contrast, the weakly damaged pyrochlore (Panda Hill) begins to recover at considerably lower temperatures (near 500 K), extending over a temperature range of ca. 300 K, up to 800 K (Raman). The pyrochlore from Blue River shows in its

  7. Molecular mechanisms in radiation damage to DNA. Progress report

    International Nuclear Information System (INIS)

    Osman, R.

    1994-01-01

    The objectives of this work are to elucidate the molecular mechanisms that are responsible for radiation-induced DNA damage. The overall goal is to understand the relationship between the chemical and structural changes produced by ionizing radiation in DNA and the resulting impairment of biological function expressed as carcinogenesis or cell death. The studies are based on theoretical explorations of possible mechanisms that link initial radiation damage in the form of base and sugar damage to conformational changes in DNA. These mechanistic explorations should lead to the formulation of testable hypotheses regarding the processes of impairment of regulation of gene expression, alteration in DNA repair, and damage to DNA structure involved in cell death or cancer

  8. The role of radiation damage analysis in the fusion program

    International Nuclear Information System (INIS)

    Doran, D.G.

    1983-01-01

    The objective of radiation damage analysis is the prediction of the performance of facility components exposed to a radiation environment. The US Magnetic Fusion Energy materials program includes an explicit damage analysis activity within the Damage Analysis and Fundamental Studies (DAFS) Program. Many of the papers in these Proceedings report work done directly or indirectly in support of the DAFS program. The emphasis of this program is on developing procedures, based on an understanding of damage mechanisms, for applying data obtained in diverse radiation environments to the prediction of component behavior in fusion devices. It is assumed that the Fusion Materials Irradiation Test Facility will be available in the late 1980s to test (and calibrate where necessary) correlation procedures to the high fluences expected in commercial reactors. (orig.)

  9. Radiation investigations during space flight

    International Nuclear Information System (INIS)

    Akatov, A.Yu.; Nevzgodina, L.V.; Sakovich, V.A.; Fekher, I.; Deme, Sh.; Khashchegan, D.

    1986-01-01

    Results of radiation investigations during ''Salyut-6'' orbital station flight are presented. The program of studying the environmental radioactivity at the station included ''Integral'' and ''Pille'' experiments. In the course of the ''Integral'' experiment absorbed dose distributions of cosmic radiation and heavy charged particle fluence for long time intervals were studied. Method, allowing one to study dose distributions and determine individual doses for any time interval rapidity and directly on board the station was tested in the course of ''Pille'' experiment for the first time. Attention is paid to measuring equipment. Effect of heavy charged particles on the cellular structure of air-dry Lactuca sativa lettuce seeds was studied in the course of radiobiological experiments conducted at ''Salyut-6'' station. It is shown, that with the increase of flight duration the frequency of cells with chromosomal aberrations increases

  10. Introduction of neutron metrology for reactor radiation damage

    International Nuclear Information System (INIS)

    Alberman, A.; Genthon, J.P.; Schneider, W.; Wright, S.B.; Zijp, W.L.

    1979-01-01

    The background of the procedures for determining irradiation parameters which are of interest in radiation damage experiments is described. The first two chapters outline the concept of damage functions and damage models. The next two chapters give information on methods to determine neutron fluences and neutron spectra. The fifth chapter gives a review of correlation data available for graphite and steels. The last chapter gives guidance how to report the relevant irradiation parameters. Attention is given to the role of the neutron spectrum in deriving values for damage fluence, energy transferred to the lattice, and number of displacements

  11. Chemical implications of heat and radiation damage to rock salt

    International Nuclear Information System (INIS)

    Pederson, L.R.

    1984-11-01

    Chemical changes induced in Palo Duro and Paradox Basin natural rock salts and in synthetic NaCl by heat and gamma radiation were investigated. Heating of unirradiated natural rock salts to 300 0 C resulted in HCl (most prevalent), SO 2 , CO 2 , and H 2 S evolution, and increased the base content of the remaining salt by not more than 10 microequivalents per gram; whereas, heating of synthetic NaCl gave no product. Gamma irradiation produced sodium colloids and neutral chlorine in amounts similar to the results of Levy and coworkers. When the irradiated salts were heated, three reactions were apparent: (1) radiation-induced defects recombined; (2) neutral chlorine was evolved; and (3) HCl, SO 2 , CO 2 , and H 2 S were evolved, similar to results for unirradiated salts. Because reaction (1) appeared to dominate over reaction (2), it is expected that the influence of radiation damage to salt on the near-field chemical environment will be minor. 4 figures, 1 table

  12. Rosiglitazone attenuates pulmonary fibrosis and radiation-induced intestinal damage

    International Nuclear Information System (INIS)

    Mangoni, M.; Gerini, C.; Sottili, M.; Cassani, S.; Stefania, G.; Biti, G.; Castiglione, F.; Vanzi, E.; Bottoncetti, A.; Pupi, A.

    2011-01-01

    Full text of publication follows: Purpose.-The aim of the study was to evaluate radioprotective effect of rosiglitazone (RGZ) on a murine model of late pulmonary damage and of acute intestinal damage. Methods.- Lung fibrosis: C57 mice were treated with the radiomimetic agent bleomycin, with or without rosiglitazone (5 mg/kg/day). To obtain an independent qualitative and quantitative measure for lung fibrosis we used high resolution CT, performed twice a week during the entire observation period. Hounsfield Units (HU) of section slides from the upper and lower lung region were determined. On day 31 lungs were collected for histological analysis. Acute intestinal damage: mice underwent 12 Gy total body irradiation with or without rosiglitazone. Mice were sacrificed 24 or 72 h after total body irradiation and ileum and colon were collected. Results.- Lung fibrosis: after bleomycin treatment, mice showed typical CT features of lung fibrosis, including irregular septal thickening and patchy peripheral reticular abnormalities. Accordingly, HU lung density was dramatically increased. Rosiglitazone markedly attenuated the radiological signs of fibrosis and strongly inhibited HU lung density increase (60% inhibition at the end of the observation period). Histological analysis revealed that in bleomycin-treated mice, fibrosis involved 50-55% of pulmonary parenchyma and caused an alteration of the alveolar structures in 10% of parenchyma, while in rosiglitazone-treated mice, fibrosis involved only 20-25% of pulmonary parenchyma, without alterations of the alveolar structures. Acute intestinal damage: 24 h after 12 Gy of total body irradiation intestinal mucosa showed villi shortening, mucosal thickness and crypt necrotic changes. Rosiglitazone showed a histological improvement of tissue structure, with villi and crypts normalization and oedema reduction. Conclusion.- These results demonstrate that rosiglitazone displays a protective effect on pulmonary fibrosis and radiation

  13. Rosiglitazone attenuates pulmonary fibrosis and radiation-induced intestinal damage

    Energy Technology Data Exchange (ETDEWEB)

    Mangoni, M.; Gerini, C.; Sottili, M.; Cassani, S.; Stefania, G.; Biti, G. [Radiotherapy Unit, Clinical Physiopathology Department, University of Florence, Firenze (Italy); Castiglione, F. [Department of Human Pathology and Oncology, University of Florence, Firenze (Italy); Vanzi, E.; Bottoncetti, A.; Pupi, A. [Nuclear Medicine Unit, Clinical Physiopathology Department, University of Florence, Firenze (Italy)

    2011-10-15

    Full text of publication follows: Purpose.-The aim of the study was to evaluate radioprotective effect of rosiglitazone (RGZ) on a murine model of late pulmonary damage and of acute intestinal damage. Methods.- Lung fibrosis: C57 mice were treated with the radiomimetic agent bleomycin, with or without rosiglitazone (5 mg/kg/day). To obtain an independent qualitative and quantitative measure for lung fibrosis we used high resolution CT, performed twice a week during the entire observation period. Hounsfield Units (HU) of section slides from the upper and lower lung region were determined. On day 31 lungs were collected for histological analysis. Acute intestinal damage: mice underwent 12 Gy total body irradiation with or without rosiglitazone. Mice were sacrificed 24 or 72 h after total body irradiation and ileum and colon were collected. Results.- Lung fibrosis: after bleomycin treatment, mice showed typical CT features of lung fibrosis, including irregular septal thickening and patchy peripheral reticular abnormalities. Accordingly, HU lung density was dramatically increased. Rosiglitazone markedly attenuated the radiological signs of fibrosis and strongly inhibited HU lung density increase (60% inhibition at the end of the observation period). Histological analysis revealed that in bleomycin-treated mice, fibrosis involved 50-55% of pulmonary parenchyma and caused an alteration of the alveolar structures in 10% of parenchyma, while in rosiglitazone-treated mice, fibrosis involved only 20-25% of pulmonary parenchyma, without alterations of the alveolar structures. Acute intestinal damage: 24 h after 12 Gy of total body irradiation intestinal mucosa showed villi shortening, mucosal thickness and crypt necrotic changes. Rosiglitazone showed a histological improvement of tissue structure, with villi and crypts normalization and oedema reduction. Conclusion.- These results demonstrate that rosiglitazone displays a protective effect on pulmonary fibrosis and radiation

  14. Radiation damage in nuclear waste ceramics

    International Nuclear Information System (INIS)

    Turcotte, R.P.; Roberts, F.P.; Rusin, J.M.; Wald, J.W.

    1982-01-01

    The text contains a number of specific observations about the radiation-induced changes in glass, glass-ceramic, and supercalcine nuclear waste forms. Other, more general conclusions can be summarized: Radiation-induced property changes follow an exponential ingrowth curve to saturation. Actinide host phases in both crystalline waste forms become X-ray amorphous. The magnitudes of the waste-form density changes observed could not be directly related to observed changes in the primary actinide phases. Although large crystal-structure changes occur in the materials studied, obvious physical degradation was not observed

  15. Effect of Mercuric Nitrate on Repair of Radiation-induced DNA Damage

    Energy Technology Data Exchange (ETDEWEB)

    Paneka, Agnieszka; Antonina, Cebulska Wasilewska [The Henryk Niewodniczanski Institute of Nuclear Physics, Krakow (Poland); Han, Min; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2009-10-15

    High concentrations of mercury can cause serious damage to the nervous system, immune system, kidneys and liver in humans. And mercury is toxic to developing embryos because mercury ions can penetrate the blood.placenta barrier to reach the embryo. Studies from human monitoring of occupational exposure to mercury vapours have shown that mercury can alter the ability of lymphocytes to repair radiation-induced DNA damage. The aim of this in vitro study was to investigate, on the molecular and cytogenetic levels, the effect of exposure to mercury ions on the kinetics of the repair process of DNA damage induced by ionising radiation.

  16. Radiation damage at the molecular level: Nanodosimetry

    International Nuclear Information System (INIS)

    Blanco, F.; Munoz, A.; Lagares, J. I.; Nunez, L.; Garcia, G.

    2013-01-01

    One of the main practical use of the model is its use as a tool of nanodosimetry which basically consists in characterizing the effect of radiation on nano volumes (comparable to the DNA of volumes) in terms of link breaks and molecular dissociations. (Author)

  17. Radiation damage on high polymer epoxies

    Energy Technology Data Exchange (ETDEWEB)

    Pak, H M [Royal Military Coll. of Canada, Kingston, ON (Canada)

    1994-12-31

    The effect of irradiation in a SLOWPOKE-2 reactor on the adhesive strength of epoxy resins was studied using the ASTM D897 standard testing procedure. Although the results were variable, indicating the doses were not well defined, nevertheless, there was evidence of strengthening associated with radiation-induced crosslinking. 2 figs., 1 tab.

  18. Radioactivity, shielding, radiation damage, and remote handling

    International Nuclear Information System (INIS)

    Wilson, M.T.

    1975-01-01

    Proton beams of a few hundred million electron volts of energy are capable of inducing hundreds of curies of activity per microampere of beam intensity into the materials they intercept. This adds a new dimension to the parameters that must be considered when designing and operating a high-intensity accelerator facility. Large investments must be made in shielding. The shielding itself may become activated and require special considerations as to its composition, location, and method of handling. Equipment must be designed to withstand large radiation dosages. Items such as vacuum seals, water tubing, and electrical insulation must be fabricated from radiation-resistant materials. Methods of maintaining and replacing equipment are required that limit the radiation dosages to workers.The high-intensity facilities of LAMPF, SIN, and TRIUMF and the high-energy facility of FERMILAB have each evolved a philosophy of radiation handling that matches their particular machine and physical plant layouts. Special tooling, commercial manipulator systems, remote viewing, and other techniques of the hot cell and fission reactor realms are finding application within accelerator facilities. (U.S.)

  19. The suppressive effect of etoposide on recovery from sublethal radiation damage in Chinese hamster V 79 cells

    International Nuclear Information System (INIS)

    Saito, Tsutomu; Shimada, Yuji; Kawamori, Jiro; Kamata, Rikisaburo

    1992-01-01

    The combined effect of radiation and etoposide on the survival of cultured Chinese hamster V 79 cells was investigated. Cells in exponential growth phase were treated with various combinations of radiation and etoposide. The surviving fraction was assessed by colony formation. Etoposide significantly reduced so-called shoulder width, as expressed in Dq (quasithreshold dose), of radiation survival curves. The reduction depended on the increase of etoposide concentrations, although steepening of slopes of exponentially regressing portions of the radiation survival curves was slight. Split dose experiments showed that cells did not recover from sublethal radiation damage in the presence of low concentration of etoposide, although they did recover from sublethal radiation damage under a drug free condition. The results show the suppressive effect of etoposide on recovery from sublethal radiation damage. The effect of a sequential combination of radiation and etoposide was also investigated. The effect was more marked when the interval between radiation and etoposide was shorter regardless of the sequence. (author)

  20. Request from radiation damage evaluation in materials

    International Nuclear Information System (INIS)

    Fukuya, Koji; Kimura, Itsuro

    2003-01-01

    Radiation transport calculations in a PWR using cross-section data sets based on JENDL3.2 showed that the calculated neutron fluence agreed well with the dosimeter measurements and that the fast neutron flux and dpa rate differed within 10% from to those calculated using ENDF/B-IV and ENDF/B-VI based data sets. Calculations of helium generation in structural materials in the PWR using ENDF/B-VI showed that the dominant source of helium is the (n, α) reaction of 59 Ni and that the calculated helium content agreed with the measurements. For accurate estimation of radiation field from a material viewpoint, it is desirable to construct proper cross-section libraries, which have a proper energy group structure and contain sufficient elements including 59 Ni as an indispensable element. (author)

  1. Extra lethal damage due to residual incompletely repaired sublethal damage in hyperfractionated and continuous radiation treatment

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.; van de Geijn, J.; Goffman, T. (ROB, DCT, NCI, NIH, Bethesda, Maryland 20892 (US))

    1991-05-01

    In the conventional linear--quadratic model of single-dose response, the {alpha} and {beta} terms reflect lethal damage created {ital during} the delivery of a dose, from two different presumed molecular processes, one linear with dose, the other quadratic. With the conventional one-fraction-per-day (or less) regimens, the sublethal damage (SLD), presumably repairing exponentially over time, is essentially completely fixed by the time of the next dose of radiation. If this assumption is true, the effects of subsequent fractions of radiation should be independent, that is, there should be little, if any, reversible damage left from previous fractions, at the time of the next dose. For multiple daily fractions, or for the limiting case, continuous radiation, this simplification may overlook damaged cells that have had insufficient time for repair. A generalized method is presented for accounting for extra lethal damage (ELD) arising from such residual SLD for hyperfractionation and continuous irradiation schemes. It may help to predict differences in toxicity and tumor control, if any, obtained with unconventional'' treatment regimens. A key element in the present model is the finite size and the dynamic character of the pool of sublethal damage. Besides creating the usual linear and quadratic components of lethal damage, each new fraction converts a certain fraction of the existing SLD into ELD, and creates some new SLD.

  2. Extra lethal damage due to residual incompletely repaired sublethal damage in hyperfractionated and continuous radiation treatment

    International Nuclear Information System (INIS)

    Chen, J.; van de Geijn, J.; Goffman, T.

    1991-01-01

    In the conventional linear--quadratic model of single-dose response, the α and β terms reflect lethal damage created during the delivery of a dose, from two different presumed molecular processes, one linear with dose, the other quadratic. With the conventional one-fraction-per-day (or less) regimens, the sublethal damage (SLD), presumably repairing exponentially over time, is essentially completely fixed by the time of the next dose of radiation. If this assumption is true, the effects of subsequent fractions of radiation should be independent, that is, there should be little, if any, reversible damage left from previous fractions, at the time of the next dose. For multiple daily fractions, or for the limiting case, continuous radiation, this simplification may overlook damaged cells that have had insufficient time for repair. A generalized method is presented for accounting for extra lethal damage (ELD) arising from such residual SLD for hyperfractionation and continuous irradiation schemes. It may help to predict differences in toxicity and tumor control, if any, obtained with ''unconventional'' treatment regimens. A key element in the present model is the finite size and the dynamic character of the pool of sublethal damage. Besides creating the usual linear and quadratic components of lethal damage, each new fraction converts a certain fraction of the existing SLD into ELD, and creates some new SLD

  3. APD Properties and Recovery from Radiation Damage

    CERN Document Server

    Baccaro, Stefania; Caruso, S; Cavallari, Francesca; Dafinei, Ioan; Diemoz, Marcella; Emeliantchik, Igor; Festinesi, Armando; Longo, Egidio; Montecchi, Marco; Organtini, Giovanni; Rosi, G

    1997-01-01

    Avalanche photodiodes will be used to detect scintillation light from PWO crystals in the CMS electromagnetic calorimeter. Properties of Hamamatsu APD are reported special attention has been devoted to the study of radiation hardness and room temperature annealing. We found a fast recovery with a time constant of 1.3 days a medium fast recovery with a lifetime of the order of 10 days and indication of a third component with very long time constant of the order of 300 days.

  4. The dependence of radiation damage analysis on neutron dosimetry

    International Nuclear Information System (INIS)

    Goland, A.N.; Parkin, D.M.

    1977-01-01

    The characteristics of defect production in neutron spectra can be determined by utilizing neutron cross section data (e.g. ENDF/B), detailed neutron spectral data and radiation damage models. The combination of neutron cross section and spectral data is a fundamental starting point in applying damage models. Calculations using these data and damage models show that there are significant differences in the way defects are produced in various neutron spectra. Nonelastic events dominate the recoil energy distribution in high-energy neutron sources such as those based upon fusion and deuteron-breakup reactions. Therefore, high-energy neutron cross sections must be measured or calculated to supplement existing data files. Radiation damage models can then be used to further characterize the diverse neutron spectra

  5. Time-scale invariances in preseismic electromagnetic radiation, magnetization and damage evolution of rocks

    Directory of Open Access Journals (Sweden)

    Y. Kawada

    2007-10-01

    Full Text Available We investigate the time-scale invariant changes in electromagnetic and mechanical energy releases prior to a rock failure or a large earthquake. The energy release processes are caused by damage evolutions such as crack propagation, motion of charged dislocation, area-enlargement of sheared asperities and repetitive creep-rate changes. Damage mechanics can be used to represent the time-scale invariant evolutions of both brittle and plastic damages. Irreversible thermodynamics applied to the damage mechanics reveals that the damage evolution produces the variations in charge, dipole and electromagnetic signals in addition to mechanical energy release, and yields the time-scale invariant patterns of Benioff electromagnetic radiation and cumulative Benioff strain-release. The irreversible thermodynamic framework of damage mechanics is also applicable to the seismo-magnetic effect, and the time-scale invariance is recognized in the remanent magnetization change associated with damage evolution prior to a rock failure.

  6. Simulation of radiation damage in Fe and Fe-Cr

    International Nuclear Information System (INIS)

    Lagerstedt, Christina

    2005-11-01

    Steel is an important structural material in nuclear reactors used for example in pressure vessels and fast reactor cladding. In reactor environments it has been observed that ferritic steels are more resistant to swelling than the austenitic steels typically used. Much effort has been put into developing basic models of FeCr alloys which can serve as model alloys for describing ferritic steels. As a result, a number of interatomic potentials for Fe and FeCr alloys exist today. For the work in this thesis, basic material properties coming from experiments or ab initio calculations were used to fit interatomic potentials for Fe, Cr and FeCr implementing both the embedded atom method and the Finnis-Sinclair formalisms. The potentials were then validated by molecular dynamic calculations of material properties such as defect formation energies, migration energies and thermal expansion. Further studies of potential performance were carried out in simulations of radiation damage cascades and thermal aging. The influence of the interatomic potential on the primary defect state in materials under irradiation was analyzed in a study comparing results obtained using four different potentials. The objective of the study was to find correlations between potential properties and the primary damage state produced in simulations of displacement cascades. The defect evolution and clustering during different cascade stages were also investigated to try to gain a better understanding of these processes

  7. THE ROLE OF RADIATION ACCIDENTS AND INDUSTRIAL APPLICATIONS OF IONIZING RADIATION SOURCES IN THE PROBLEM OF RADIATION DAMAGE

    OpenAIRE

    Кіхтенко, Ігор Миколайович

    2016-01-01

    Subject of research – the relevance of radiation damage at modern development of industry and medicine. In the world of radiation sources used in different fields of practice and their application in the future will increase, which greatly increases the likelihood of injury in a significant contingent of people.Research topic – the definition of the role of nuclear energy and the industrial use of ionizing radiation sources in the problem of radiation damage. The purpose of research – identif...

  8. Role of endothelium in radiation-induced normal tissue damages

    International Nuclear Information System (INIS)

    Milliat, F.

    2007-05-01

    More than half of cancers are treated with radiation therapy alone or in combination with surgery and/or chemotherapy. The goal of radiation therapy is to deliver enough ionising radiation to destroy cancer cells without exceeding the level that the surrounding healthy cells can tolerate. Unfortunately, radiation-induced normal tissue injury is still a dose limiting factor in the treatment of cancer with radiotherapy. The knowledge of normal tissue radiobiology is needed to determine molecular mechanisms involved in normal tissue pathogenic pathways in order to identify therapeutic targets and develop strategies to prevent and /or reduce side effects of radiation therapy. The endothelium is known to play a critical role in radiation-induced injury. Our work shows that endothelial cells promote vascular smooth muscle cell proliferation, migration and fibro-genic phenotype after irradiation. Moreover, we demonstrate for the first time the importance of PAI-1 in radiation-induced normal tissue damage suggesting that PAI-1 may represent a molecular target to limit injury following radiotherapy. We describe a new role for the TGF-b/Smad pathway in the pathogenesis of radiation-induced damages. TGF-b/Smad pathway is involved in the fibro-genic phenotype of VSMC induced by irradiated EC as well as in the radiation-induced PAI-1 expression in endothelial cells. (author)

  9. Radiation Damage Theory: Past, Present and Future

    International Nuclear Information System (INIS)

    Barashev, Aleksandr; Golubov, Stanislav I.

    2009-01-01

    Efforts of many scientists for more than a half of a century have resulted in substantial understanding of the response of various materials to irradiation. The theory has contributed significantly to this process but has not acquired a status allowing it to play a decisive role in creating radiation-resistant materials. Moreover, some theoretical predictions are in contradiction with observations, which indicates that something important has escaped attention. In the present paper, the current theoretical framework and experimental data are analyzed to elucidate the reasons for such a situation. A way of developing a predictive theory is proposed.

  10. Animal Models of Ionizing Radiation Damage

    Science.gov (United States)

    1992-01-01

    194. Stepanovic, S.R., and J.L. Nikolic, The Effect of X -irradiation on the Amount of Dopamine in Corpus Striatum of the Rat, Experientia, 35:111...Effect of X -irradiation on the Fragility of Rat Spleen Lysosomes, Radiat. Res., 20:741-750, 1963. 324. Rappaport, D.A., Influence of Total-body X -rays...NUMER C DOMB No. 0704-0188 Pubk€ "mt burden for Vft collectio al 0.0oni is san i jo avwa I how nemeai m n k x W o rqvWin srucilim seard" af da sources

  11. Radiation damage effects on calorimeter compensation

    International Nuclear Information System (INIS)

    Gabriel, T.A.; Handler, T.

    1990-01-01

    An important consideration in the design of a detector that is to be used at the Superconducting Super Collider (SSC) is the response of the calorimeter to electromagnetic and hadronic particles and the equality of those responses for different types of particles at equal incident energies, i.e. compensation. However, as the simulations that are reported show, the compensation characteristics of a calorimeter can be seriously compromised over a relatively short period of time due to the large radiation levels that are expected in the SSC environment. 6 refs., 3 figs

  12. ANL/WSU radiation damage studies

    International Nuclear Information System (INIS)

    Jankowski, D.; Lopiano, D.; Proudfoot, J.; Underwood, D.; Miles, L.; Neidiger, J.; Tripard, G.

    1993-01-01

    We report preliminary results for the radiation hardness of (polystryrene) plastic scintillator stacks using a spectrum of energy hardened neutrons from a MARK-III TRIGA reactor. The total dose ranged from 100 KRad to 3MRad. The corresponding fluence was 3.8 x 10 13 to 3.8 x 10 14 (n/cm/cm) with the gamma contribution on the order 2--3% (of fluence). The measurements used Li-6, Li-7 Thermo-luminescence dosimeters. Radiochromic/GaF- Chromic film, and activated foils simultaneously allowing an inter-comparison of these various methods of dosimetry

  13. Raman study of radiation-damaged zircon under hydrostatic compression

    Science.gov (United States)

    Nasdala, Lutz; Miletich, Ronald; Ruschel, Katja; Váczi, Tamás

    2008-12-01

    Pressure-induced changes of Raman band parameters of four natural, gem-quality zircon samples with different degrees of self-irradiation damage, and synthetic ZrSiO4 without radiation damage, have been studied under hydrostatic compression in a diamond anvil cell up to ~10 GPa. Radiation-damaged zircon shows similar up-shifts of internal SiO4 stretching modes at elevated pressures as non-damaged ZrSiO4. Only minor changes of band-widths were observed in all cases. This makes it possible to estimate the degree of radiation damage from the width of the ν3(SiO4) band of zircon inclusions in situ, almost independent from potential “fossilized pressures” or compressive strain acting on the inclusions. An application is the non-destructive analysis of gemstones such as corundum or spinel: broadened Raman bands are a reliable indicator of self-irradiation damage in zircon inclusions, whose presence allows one to exclude artificial color enhancement by high-temperature treatment of the specimen.

  14. 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.

  15. Multiscale approach to the physics of radiation damage with ions

    Energy Technology Data Exchange (ETDEWEB)

    Surdutovich, Eugene [Physics Department, Oakland University, 2200 N. Squirrel Rd., Rochester MI 48309 (United States); Solov' yov, Andrey V. [Frankfurt Institute for Advanced Studies, Goethe University, Ruth-Moufang-Str. 1, Frankfurt am Main 60438 (Germany)

    2013-04-19

    We review a multiscale approach to the physics of ion-beam cancer therapy, an approach suggested in order to understand the interplay of a large number of phenomena involved in radiation damage scenario occurring on a range of temporal, spatial, and energy scales. We briefly overview its history and present the current stage of its development. The differences of the multiscale approach from other methods of understanding and assessment of radiation damage are discussed as well as its relationship to other branches of physics, chemistry and biology.

  16. Advances in SSTR techniques for dosimetry and radiation damage measurements

    International Nuclear Information System (INIS)

    Gold, R.; Roberts, J.H.; Ruddy, F.H.

    1979-01-01

    Solid state track recorders (SSTR) have been applied in the diverse nuclear reactor research. Two recent advances are described which possess outstanding relevance for reactor research, namely the evolvement of SSTR radiation damage monitors and the development of CR-39, a new plastic SSTR of extremely high sensitivity. Results from high fluence irradiations of natural quartz crystal SSTR are used to illustrate the concept of the SSTR radiation damage monitor. Response characteristics of CR-39 are presented with emphasis on the remarkable proton sensitivity of this new SSTR

  17. 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.)

  18. 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.)

  19. Radiation damage in BaF2 crystals

    International Nuclear Information System (INIS)

    Woody, C.L.; Kierstead, J.A.; Levy, P.W.; Stoll, S.

    1991-01-01

    The effects of radiation damage and recovery have been studied in BaF 2 crystals exposed to 60 Co radiation. The change in optical transmission and scintillation light output have been measured as a function of dose up to 4.7 x 10 6 rad. Although some crystals exhibit a small change in transmission, a greater change in scintillation light output is observed. Several 25 cm long crystals whichhave been irradiated show large changes in both transmission and light output. Recovery from radiation damage has been studied as a function of time and exposure to UV light. A long lived radiation induced phosphorescence has been observed in all irradiated samples which is distinct from the standard fast and slow scintillation emissions. The emission spectrum of the phosphorescence has been measured and shown a peakat ∼330 nm, near the region of the slow scintillation component. Results are given on the dependence of the decay time of the phosphorescence with dose

  20. 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)

  1. Radiation induced DNA damage and repair in mutagenesis

    International Nuclear Information System (INIS)

    Strniste, G.F.; Chen, D.J.; Okinaka, R.T.

    1987-01-01

    The central theme in cellular radiobiological research has been the mechanisms of radiation action and the physiological response of cells to this action. Considerable effort has been directed toward the characterization of radiation-induced DNA damage and the correlation of this damage to cellular genetic change that is expressed as mutation or initiating events leading to cellular transformation and ultimately carcinogenesis. In addition, there has been a significant advancement in their understanding of the role of DNA repair in the process of mutation leading to genetic change in cells. There is extensive literature concerning studies that address radiation action in both procaryotic and eucaryotic systems. This brief report will make no attempt to summarize this voluminous data but will focus on recent results from their laboratory of experiments in which they have examined, at both the cellular and molecular levels, the process of ionizing radiation-induced mutagenesis in cultured human cells

  2. Conformational variation of proteins at room temperature is not dominated by radiation damage

    International Nuclear Information System (INIS)

    Russi, Silvia; González, Ana; Kenner, Lillian R.; Keedy, Daniel A.; Fraser, James S.; Bedem, Henry van den

    2017-01-01

    Protein crystallography data collection at synchrotrons is routinely carried out at cryogenic temperatures to mitigate radiation damage. Although damage still takes place at 100 K and below, the immobilization of free radicals increases the lifetime of the crystals by approximately 100-fold. Recent studies have shown that flash-cooling decreases the heterogeneity of the conformational ensemble and can hide important functional mechanisms from observation. These discoveries have motivated increasing numbers of experiments to be carried out at room temperature. However, the trade-offs between increased risk of radiation damage and increased observation of alternative conformations at room temperature relative to cryogenic temperature have not been examined. A considerable amount of effort has previously been spent studying radiation damage at cryo-temperatures, but the relevance of these studies to room temperature diffraction is not well understood. Here, the effects of radiation damage on the conformational landscapes of three different proteins (T. danielli thaumatin, hen egg-white lysozyme and human cyclophilin A) at room (278 K) and cryogenic (100 K) temperatures are investigated. Increasingly damaged datasets were collected at each temperature, up to a maximum dose of the order of 10 7 Gy at 100 K and 10 5 Gy at 278 K. Although it was not possible to discern a clear trend between damage and multiple conformations at either temperature, it was observed that disorder, monitored by B-factor-dependent crystallographic order parameters, increased with higher absorbed dose for the three proteins at 100 K. At 278 K, however, the total increase in this disorder was only statistically significant for thaumatin. A correlation between specific radiation damage affecting side chains and the amount of disorder was not observed. Lastly, this analysis suggests that elevated conformational heterogeneity in crystal structures at room temperature is observed despite radiation

  3. Energy Dependence of Proton Radiation Damage in Si-Sensors

    CERN Document Server

    AUTHOR|(CDS)2084399; Neubüser, C.

    2014-01-01

    Irradiation experiments on silicon sensors are used to mimic the radiation environment at collider experiments with the aim to forecast the change of the electrical properties of a detector with irradiation. Measurements on irradiated sensors are invaluable in choosing a material well suited for a silicon tracking detector. This is especially true for the upgraded detectors to be used in the high-luminosity phase of the LHC (HL-LHC), where silicon sensors as currently used would suffer severe loss in signal from irradiation with charged and neutral hadrons.\\\\ The CMS Tracker Collaboration has initiated irradiation studies with protons with energies ranging from 23 MeV to 23 GeV. They are often used instead of charged hadrons, their radiation induced damage to the silicon being rather similar. However, in oxygen rich silicon, NIEL violation concerning the full depletion voltage has been observed.\\\\ In this paper results from investigations on bulk defects compared to the change of the electrical properties of ...

  4. 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.)

  5. 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 ...

  6. Monitoring the Radiation Damage of the ATLAS Pixel Detector

    CERN Document Server

    Cooke, M; The ATLAS collaboration

    2012-01-01

    The Pixel Detector is the innermost charged particle tracking component employed by the ATLAS experiment at the CERN Large Hadron Collider (LHC). The instantaneous luminosity delivered by the LHC, now routinely in excess of 5x10^{33} cm^{-2} s^{-1}, results in a rapidly increasing accumulated radiation dose to the detector. Methods based on the sensor depletion properties and leakage current are used to monitor the evolution of the radiation damage, and results from the 2011 run are presented.

  7. Monitoring the radiation damage of the ATLAS pixel detector

    International Nuclear Information System (INIS)

    Cooke, M.

    2013-01-01

    The pixel detector is the innermost charged particle tracking component employed by the ATLAS experiment at the CERN Large Hadron Collider (LHC). The instantaneous luminosity delivered by the LHC, now routinely in excess of 5×10 33 cm −2 s −1 , results in a rapidly increasing accumulated radiation dose to the detector. Methods based on the sensor depletion properties and leakage current are used to monitor the evolution of the radiation damage, and results from the 2011 run are presented

  8. Modification of radiation damage by naturally occurring substances

    International Nuclear Information System (INIS)

    Prasad, K.N.

    1984-01-01

    The major objectives of studying the modification of radiation sensitivity have been (1) to identify a compound that will produce a differential protection or sensitization of the effect of irradiation on normal and tumor tissue, and (2) to understand more about the mechanisms of radiation damage. In spite of massive research on this particular problem since World War II, the first objective remains elusive. During this period, numerous radioprotective and radiosensitizing agents have been identified. These agents have served as important biologic tools for increasing our understanding of radiation injuries. Most of these substances are synthetic compounds and are very toxic to humans. In addition, very few of the compounds provide differential modifications of the effect of radiation on tumor and normal cells. This chapter presents objectives for identifying naturally occurring substances that modify the effect of x-radiation on mammalian cells and discusses the role of physiologic substances in modifying radiation injuries on mammalian normal and tumor cells

  9. Radiation damage to DNA: The importance of track structure

    International Nuclear Information System (INIS)

    Hill, M.A.

    1999-01-01

    A wide variety of biological effects are induced by ionizing radiation, from cell death to mutations and carcinogenesis. The biological effectiveness is found to vary not only with the absorbed dose but also with the type of radiation and its energy, i.e., with the nature of radiation tracks. An overview is presented of some of the biological experiments using different qualities of radiation, which when compared with Monte Carlo track structure studies, have highlighted the importance of the localized spatial properties of stochastic energy deposition on the nanometer scale at or near DNA. The track structure leads to clustering of damage which may include DNA breaks, base damage etc., the complexity of the cluster and therefore its biological repairability varying with radiation type. The ability of individual tracks to produce clustered damage, and the subsequent biological response are important in the assessment of the risk associated with low-level human exposure. Recent experiments have also shown that biological response to radiation is not always restricted to the 'hit' cell but can sometimes be induced in 'un-hit' cells near by

  10. Radiation damage in carbon-carbon composites

    International Nuclear Information System (INIS)

    Burchell, T.D.; Eartherly, W.P.; Nelson, G.E.

    1992-01-01

    Graphite and carbon-carbon composite materials are widely used in plasma facing applications in current Tokamak devices such as TFTR and DIIID in the USA, JET, Tore Supra and TEXTOR in Europe, and JT-60U in Japan. Carbon-carbon composites are attractive choices for Tokamak limiters and diverters because of their low atomic number, high thermal shock resistance, high melting point, and high thermal conductivity. Next generation machines such as the International Thermonuclear Experimental Reactor (ITER) will utilize carbon-carbon composites in their first wall and diverter. ITER will be an ignition machine and thus will produce substantial neutron fluences from the D-T fusion reaction. The resultant high energy neutrons will cause carbon atom displacements in the plasma facing materials which will markedly affect their structure and physical properties. The effect of neutron damage on graphite has been studied for over forty years. Recently the effects of neutron irradiation on the fusion relevant graphite GraphNOL N3M was reviewed. In contrast to graphite, relatively little work has been performed to elucidate the effects of neutron irradiation on carbon-carbon composites. The results of our previous irradiation experiments have been published elsewhere. Here the irradiation induced dimensional changes in 1D, 2D, and 3D carbon-carbon composites are reported for fluences up to 4.7 dpa at an irradiation temperature of 600 degree C

  11. 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)

  12. Radiation-induced normal tissue damage: implications for radiotherapy

    International Nuclear Information System (INIS)

    Prasanna, Pataje G.

    2014-01-01

    Radiotherapy is an important treatment modality for many malignancies, either alone or as a part of combined modality treatment. However, despite technological advances in physical treatment delivery, patients suffer adverse effects from radiation therapy due to normal tissue damage. These side effects may be acute, occurring during or within weeks after therapy, or intermediate to late, occurring months to years after therapy. Minimizing normal tissue damage from radiotherapy will allow enhancement of tumor killing and improve tumor control and patients quality of life. Understanding mechanisms through which radiation toxicity develops in normal tissue will facilitate the development of next generation radiation effect modulators. Translation of these agents to the clinic will also require an understanding of the impact of these protectors and mitigators on tumor radiation response. In addition, normal tissues vary in radiobiologically important ways, including organ sensitivity to radiation, cellular turnover rate, and differences in mechanisms of injury manifestation and damage response. Therefore, successful development of radiation modulators may require multiple approaches to address organ/site-specific needs. These may include treatments that modify cellular damage and death processes, inflammation, alteration of normal flora, wound healing, tissue regeneration and others, specifically to counter cancer site-specific adverse effects. Further, an understanding of mechanisms of normal tissue damage will allow development of predictive biomarkers; however harmonization of such assays is critical. This is a necessary step towards patient-specific treatment customization. Examples of important adverse effects of radiotherapy either alone or in conjunction with chemotherapy, and important limitations in the current approaches of using radioprotectors for improving therapeutic outcome will be highlighted. (author)

  13. LHCb: Radiation Damage in the LHCb VELO

    CERN Multimedia

    Rodriguez Perez, P

    2012-01-01

    LHCb is a dedicated experiment to study new physics in the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. The beauty and charm hadrons are identified through their flight distance in the Vertex Locator (VELO), and hence the detector is critical for both the trigger and offline physics analyses. The 88 VELO sensors are all n-on-n type but one, which is made from n-on-p silicon, and is the only n-on-p module silicon sensor operated at the LHC. The sensors have an inner radius of only 7 mm from the LHC beam and an outer radius of 42 mm, consequently the sensors receive a large and non-uniform radiation dose. The LHCb is planned to record an integrated luminosity up to 5 $fb^{-1}$ with collision energies between 7 and 14 TeV before 2018. The leakage current in the sensors has increased significantly following the delivered luminosity, and decreased during shutdown periods due to annealing. The effective depletion voltage of the sensors is measured from the charge collection effi...

  14. Radiation Damage Studies of Silicon Photomultipliers

    CERN Document Server

    Bohn, P; Hazen, E.; Heering, A.; Rohlf, J.; Freeman, J.; Los, Sergey V.; Cascio, E.; Kuleshov, S.; Musienko, Y.; Piemonte, C.

    2008-01-01

    We report on the measurement of the radiation hardness of silicon photomultipliers (SiPMs) manufactured by Fondazione Bruno Kessler in Italy (1 mm$^2$ and 6.2 mm$^2$), Center of Perspective Technology and Apparatus in Russia (1 mm$^2$ and 4.4 mm$^2$), and Hamamatsu Corporation in Japan (1 mm$^2$). The SiPMs were irradiated using a beam of 212 MeV protons at Massachusetts General Hospital, receiving fluences of up to $3 \\times 10^{10}$ protons per cm$^2$ with the SiPMs at operating voltage. Leakage currents were read continuously during the irradiation. The delivery of the protons was paused periodically to record scope traces in response to calibrated light pulses to monitor the gains, photon detection efficiencies, and dark counts of the SiPMs. The leakage current and dark noise are found to increase with fluence. Te leakage current is found to be proportional to the mean square deviation of the noise distribution, indicating the dark counts are due to increased random individual pixel activation, while SiPM...

  15. UV and ionizing radiations induced DNA damage, differences and similarities

    Science.gov (United States)

    Ravanat, Jean-Luc; Douki, Thierry

    2016-11-01

    Both UV and ionizing radiations damage DNA. Two main mechanisms, so-called direct and indirect pathways, are involved in the degradation of DNA induced by ionizing radiations. The direct effect of radiation corresponds to direct ionization of DNA (one electron ejection) whereas indirect effects are produced by reactive oxygen species generated through water radiolysis, including the highly reactive hydroxyl radicals, which damage DNA. UV (and visible) light damages DNA by again two distinct mechanisms. UVC and to a lesser extend UVB photons are directly absorbed by DNA bases, generating their excited states that are at the origin of the formation of pyrimidine dimers. UVA (and visible) light by interaction with endogenous or exogenous photosensitizers induce the formation of DNA damage through photosensitization reactions. The excited photosensitizer is able to induce either a one-electron oxidation of DNA (type I) or to produce singlet oxygen (type II) that reacts with DNA. In addition, through an energy transfer from the excited photosensitizer to DNA bases (sometime called type III mechanism) formation of pyrimidine dimers could be produced. Interestingly it has been shown recently that pyrimidine dimers are also produced by direct absorption of UVA light by DNA, even if absorption of DNA bases at these wavelengths is very low. It should be stressed that some excited photosensitizers (such as psoralens) could add directly to DNA bases to generate adducts. The review will described the differences and similarities in terms of damage formation (structure and mechanisms) between these two physical genotoxic agents.

  16. Potential radiation damage: Storage tanks for liquid radioactive waste

    International Nuclear Information System (INIS)

    Caskey, G.R. Jr.

    1992-01-01

    High level waste at SRS is stored in carbon steel tanks constructed during the period 1951 to 1981. This waste contains radionuclides that decay by alpha, beta, or gamma emission or are spontaneous neutronsources. Thus, a low intensity radiation field is generated that is capable of causing displacement damage to the carbon steel. The potential for degradation of mechanical properties was evaluated by comparing the estimated displacement damage with published data relating changes in Charpy V-notch (CVN) impact energy to neutron exposure. Experimental radiation data was available for three of the four grades of carbonsteel from which the tanks were constructed and is applicable to all four steels. Estimates of displacement damage arising from gamma and neutron radiation have been made based on the radionuclide contents for high level waste that are cited in the Safety Analysis Report (SAR) for the Liquid Waste Handling Facilities in the 200-Area. Alpha and beta emissions do not penetrate carbon steel to a sufficient depth to affect the bulk properties of the tank walls but may aggravate corrosion processes. The damage estimates take into account the source of the waste (F- or H-Area), the several types of tank service, and assume wateras an attenuating medium. Estimates of displacement damage are conservative because they are based on the highest levels of radionuclide contents reported in the SAR and continuous replenishment of the radionuclides

  17. Nuclear data for radiation damage assessment and related safety aspects

    International Nuclear Information System (INIS)

    Kocherov, N.P.

    1989-12-01

    The IAEA Advisory Group Meeting on Nuclear Data for Radiation Damage Assessment and Related Safety Aspects was held at the IAEA Headquarters in Vienna, 19-22 September 1989. This report contains the conclusions and recommendations of this meeting. The papers which the participants prepared for and presented at the meeting will be published as an IAEA Technical Document. (author)

  18. Effect of Rosiglitazone on Radiation Damage in Bone Marrow Hemopoiesis

    International Nuclear Information System (INIS)

    Benko', Klara; Pintye, Eva; Szabo, Boglarka; Geresi, Krisztina; Megyeri, Attila; Benko, Ilona

    2008-01-01

    To study radiobiological effects and drugs, which can modify radiation injury, has an importance if we would like to avoid harmful effects of radiation due to emergency situations or treat patients with malignant diseases by radiotherapy. During the long treatment schedules patients may be treated by not only anticancer but many other drugs because of accompanying diseases. These drugs may also modify radiobiological effects. Rosiglitazone pre-treatment proved to be myeloprotective and accelerated recovery of 5-fluorouracil-damaged bone marrow in our previous experiments. Our new studies are designed to evaluate whether rosiglitazone has similar beneficial effects in radiation-damaged hemopoiesis. Bone marrow damage was precipitated by total body irradiation (TBI) using single increasing doses (2-10 Gy) of γ--irradiation in groups of mice. Lethality was well correlated with damage in hemopoiesis measured by cellularity of bone marrow (LD 50 values were 4.8 and 5.3 gray respectively). Rosiglitazone, an insulin-sensitizing drug, had no significant effect on bone marrow cellularity. Insulin resistance associated with obesity or diabetes mellitus type 2 is intensively growing among cancer patients requiring some kind of radiotherapy. Therefore it is important to know whether drugs used for their therapy can modify radiation effects.

  19. Effect of Rosiglitazone on Radiation Damage in Bone Marrow Hemopoiesis

    Science.gov (United States)

    Benkő, Klára; Pintye, Éva; Szabó, Boglárka; Géresi, Krisztina; Megyeri, Attila; Benkő, Ilona

    2008-12-01

    To study radiobiological effects and drugs, which can modify radiation injury, has an importance if we would like to avoid harmful effects of radiation due to emergency situations or treat patients with malignant diseases by radiotherapy. During the long treatment schedules patients may be treated by not only anticancer but many other drugs because of accompanying diseases. These drugs may also modify radiobiological effects. Rosiglitazone pre-treatment proved to be myeloprotective and accelerated recovery of 5-fluorouracil-damaged bone marrow in our previous experiments. Our new studies are designed to evaluate whether rosiglitazone has similar beneficial effects in radiation-damaged hemopoiesis. Bone marrow damage was precipitated by total body irradiation (TBI) using single increasing doses (2-10 Gy) of γ—irradiation in groups of mice. Lethality was well correlated with damage in hemopoiesis measured by cellularity of bone marrow (LD50 values were 4.8 and 5.3 gray respectively). Rosiglitazone, an insulin-sensitizing drug, had no significant effect on bone marrow cellularity. Insulin resistance associated with obesity or diabetes mellitus type 2 is intensively growing among cancer patients requiring some kind of radiotherapy. Therefore it is important to know whether drugs used for their therapy can modify radiation effects.

  20. Experimental data available for radiation damage modelling in reactor materials

    International Nuclear Information System (INIS)

    Wollenberger, H.

    Radiation damage modelling requires rate constants for production, annihilation and trapping of defects. The literature is reviewed with respect to experimental determination of such constants. Useful quantitative information exists only for Cu and Al. Special emphasis is given to the temperature dependence of the rate constants

  1. Ion bombardment simulation: a review related to fusion radiation damage

    International Nuclear Information System (INIS)

    Brimhall, J.L.

    1975-01-01

    Prime emphasis is given to reviewing the ion bombardment data on the refractory metals molybdenum, niobium and vanadium which have been proposed for use in advanced fusion devices. The temperature and dose dependence of the void parameters are correlated among these metals. The effect of helium and hydrogen gas on the void parameters is also included. The similarities and differences of the response of these materials to high dose, high temperature radiation damage are evaluated. Comparisons are made with results obtained from stainless steel and nickel base alloys. The ion bombardment data is then compared and correlated, as far as possible, with existing neutron data on the refractory metals. The theoretically calculated damage state produced by neutrons and ions is also briefly discussed and compared to experimental data wherever possible. The advantages and limitations of ion simulation in relation to fusion radiation damage are finally summarized

  2. Radiation damage resistance in mercuric iodide X-ray detectors

    Energy Technology Data Exchange (ETDEWEB)

    Patt, B E; Dolin, R C; Devore, T M; Markakis, J M [EG and G Energy Measurements, Inc., Goleta, CA (USA); Iwanczyk, J S; Dorri, N [Xsirius, Inc., Marina del Rey, CA (USA); Trombka, J [National Aeronautics and Space Administration, Greenbelt, MD (USA). Goddard Space Flight Center

    1990-12-20

    Mercuric iodide (HgI{sub 2}) radiation detectors show great potential as ambient-temperature solid-state detectors for X-rays, gamma rays and visible light, with parameters that are competitive with existing technologies. In a previous experiment, HgI{sub 2} detectors irradiated with 10 MeV protons/cm{sup 2} exhibited no damage. The 10 MeV protons represent only the low range of the spectrum of energies that are important. An experiment has been conducted at the Saturne accelerator facility at Saclay, France, to determine the susceptibility of these detectors to radiation damage by high-energy (1.5 GeV) protons. The detectors were irradiated to a fluence of 10{sup 8} protons/cm{sup 2}. This fluence is equivalent to the cosmic radiation expected in a one-year period in space. The resolution of the detectors was measured as a function of the integral dose. No degradation in the response of any of the detectors or spectrometers was seen. It is clear from this data that HgI{sub 2} has extremely high radiation-damage resistance, exceeding that of most other semiconductor materials used for radiation detectors. Based on the results shown to date, HgI{sub 2} detectors are suitable for applications in which they may be exposed to high integral dose levels. (orig.).

  3. Radiation induced damage to the lipid contents of bacteria and cultured mammalian cells

    International Nuclear Information System (INIS)

    Gholipour Khalili, K.

    1993-01-01

    In this study, exponentially growing phase of E. Coli. K12-N167 and cultured mouse leukemic L5178Y were used to study the effect of gamma irradiation on phospholipid contents. Following irradiation, both bacteria and cultured cells were incubated with either 14 C or 32 P labelled precursors for periods of cell division time. Phospholipid composition and their contents were detected in both the bacteria and cultured cells by using liquid scintillation counting and autoradiography methods. In contrast, as radiation dose increased, the Phospholipid contents were decreased in the both bacteria and cultured cells. It was concluded that the changes of phospholipid contents may result to altered activities of phospholipid pathway enzymes damaged by a radiation dose. The results of this investigation would be helpful in control of induced radiation damages in cell killings in radiation workers and radiation treatment of human cancer in the clinics. (author). 35 refs, 3 figs, 4 tabs

  4. Temperature effects on radiation damage in plastic detectors

    International Nuclear Information System (INIS)

    Mendoza A, D.

    1996-01-01

    The objective of present work was to study the temperature effect on radiation damage registration in the structure of a Solid State Nuclear Track Detector of the type CR-39. In order to study the radiation damage as a function of irradiation temperature, sheets of CR-39 detectors were irradiated with electron beams, simulating the interaction of positive ions. CR-39 detectors were maintained at a constant temperature from room temperature up to 373 K during irradiation. Two techniques were used from analyzing changes in the detector structure: Electronic Paramagnetic Resonance (EPR) and Infrared Spectroscopy (IR). It was found by EPR analysis that the amount of free radicals decrease as irradiation temperature increases. The IR spectrums show yield of new functional group identified as an hydroxyl group (OH). A proposed model of interaction of radiation with CR-39 detectors is discussed. (Author)

  5. Introduction to neutron metrology for reactor radiation damage

    International Nuclear Information System (INIS)

    Alberman, A.; Genthon, J.P.; Wright, S.B.; Zijp, W.L.

    1977-01-01

    This document, prepared by members of the Irradiation Damage Subgroup of the Euratom Working Group on Reactor Dosimetry (EWGRD) describes the background of the procedures for determining irradiation parameters which are of interest in radiation damage experiments. The first two chapters outline the concept of damage functions and damge models. The next two chapters give information on methods to determine neutron fluences and neutron spectra. The fifth chapter gives a review of correlation data available for graphite and steels. The last chapter gives guidance how to report the relevant irradiation parameters. Attention is given to the role of the neutron spectrum in deriving values for damage fluence, energy transferred to the lattice, and number of displacements. A suggested list to report data relevant to the irradiation, the instrumentation and the testing of material is included

  6. Radiation damage in A-15 materials: EXAFS studies

    International Nuclear Information System (INIS)

    Knapp, G.S.; Kampwirth, R.T.; Georgopoulos, P.; Brown, B.S.

    1980-01-01

    EXAFS measurements are useful in determining the local atomic environment of a particular element in a solid. Since there has been some controversy about the nature of the defects produced in A-15 materials by radiation damage, such studies were carried out on some A-15 compounds, V 3 Ga which was damaged by neutrons, as well as Nb 3 Ge damaged by 2.5 MeV a particles. In the V 3 Ga sample, site exchange disorder seems to be the most important result of the neutron damage with less than 20% of the vanadium atoms on wrong sites. However, in the Nb 3 Ge samples in addition to site exchange disorder, an unusual splitting of the first near-neighbor distance between the Ge and Nb is found. This splitting, approximately 0.2 A, may explain the large Debye Waller factors observed by Burbank et al

  7. Radiation damage and annealing in plutonium tetrafluoride

    Science.gov (United States)

    McCoy, Kaylyn; Casella, Amanda; Sinkov, Sergey; Sweet, Lucas; McNamara, Bruce; Delegard, Calvin; Jevremovic, Tatjana

    2017-12-01

    A sample of plutonium tetrafluoride that was separated prior to 1966 at the Hanford Site in Washington State was analyzed at the Pacific Northwest National Laboratory (PNNL) in 2015 and 2016. The plutonium tetrafluoride, as received, was an unusual color and considering the age of the plutonium, there were questions about the condition of the material. These questions had to be answered in order to determine the suitability of the material for future use or long-term storage. Therefore, thermogravimetric/differential thermal analysis and X-ray diffraction evaluations were conducted to determine the plutonium's crystal structure, oxide content, and moisture content; these analyses reported that the plutonium was predominately amorphous and tetrafluoride, with an oxide content near ten percent. Freshly fluorinated plutonium tetrafluoride is known to be monoclinic. During the initial thermogravimetric/differential thermal analyses, it was discovered that an exothermic event occurred within the material near 414 °C. X-ray diffraction analyses were conducted on the annealed tetrafluoride. The X-ray diffraction analyses indicated that some degree of recrystallization occurred in conjunction with the 414 °C event. The following commentary describes the series of thermogravimetric/differential thermal and X-ray diffraction analyses that were conducted as part of this investigation at PNNL.

  8. Radiation damage and annealing in plutonium tetrafluoride

    Energy Technology Data Exchange (ETDEWEB)

    McCoy, Kaylyn; Casella, Amanda; Sinkov, Sergey; Sweet, Lucas; McNamara, Bruce; Delegard, Calvin; Jevremovic, Tatjana

    2017-12-01

    Plutonium tetrafluoride that was separated prior to 1966 at the Hanford Site in Washington State was analyzed at the Pacific Northwest National Laboratory (PNNL) in 2015 and 2016. The plutonium tetrafluoride, as received, was an off-normal color and considering the age of the plutonium, there were questions about the condition of the material. These questions had to be answered in order to determine the suitability of the material for future use or long-term storage. Therefore, Thermogravimetric/Differential Thermal Analysis and X-ray Diffraction evaluations were conducted to determine the plutonium’s crystal structure, oxide content, and moisture content; these analyses reported that the plutonium was predominately amorphous and tetrafluoride, with an oxide content near ten percent. Freshly fluorinated plutonium tetrafluoride is known to be monoclinic. During the initial Thermogravimetric/Differential Thermal analyses, it was discovered that an exothermic event occurred within the material near 414°C. X-ray Diffraction analyses were conducted on the annealed tetrafluoride. The X-ray Diffraction analyses indicated that some degree of recrystallization occurred in conjunction with the 414°C event. The following commentary describes the series of Thermogravimetric/Differential Thermal and X-ray Diffraction analyses that were conducted as part of this investigation at PNNL, in collaboration with the University of Utah Nuclear Engineering Program.

  9. Radiation damage and annealing in plutonium tetrafluoride

    International Nuclear Information System (INIS)

    McCoy, Kaylyn; Casella, Amanda; Sinkov, Sergey

    2017-01-01

    A sample of plutonium tetrafluoride that was separated prior to 1966 at the Hanford Site in Washington State was analyzed at the Pacific Northwest National Laboratory (PNNL) in 2015 and 2016. The plutonium tetrafluoride, as received, was an unusual color and considering the age of the plutonium, there were questions about the condition of the material. These questions had to be answered in order to determine the suitability of the material for future use or long-term storage. Therefore, thermogravimetric/differential thermal analysis and X-ray diffraction evaluations were conducted to determine the plutonium's crystal structure, oxide content, and moisture content; these analyses reported that the plutonium was predominately amorphous and tetrafluoride, with an oxide content near ten percent. Freshly fluorinated plutonium tetrafluoride is known to be monoclinic. And during the initial thermogravimetric/differential thermal analyses, it was discovered that an exothermic event occurred within the material near 414 °C. X-ray diffraction analyses were conducted on the annealed tetrafluoride. The X-ray diffraction analyses indicated that some degree of recrystallization occurred in conjunction with the 414 °C event. This commentary describes the series of thermogravimetric/differential thermal and X-ray diffraction analyses that were conducted as part of this investigation at PNNL.

  10. Post-flood damage data: requirements for disaster forensic investigation

    Directory of Open Access Journals (Sweden)

    Dolan Martin

    2016-01-01

    Full Text Available Disaster forensic investigation analyses the unfolding of a disaster and attempts to identify its multiple causes of damage which can lead to (i improved disaster prevention and management from lessons learnt, and (ii more effective mitigation measures in the aftermath of a disaster. The way in which damage data are collected after a flood event as well as the types of collected data influences their usability within forensic investigations. In order to explore whether or not existing data can be used for disaster forensic analysis, the European Project IDEA (Improving Damage assessments to Enhance cost-benefit Analyses is investigating existing gaps in damage information so as to identify possible paths towards improving data quality. This paper focuses in detail on a forensic analysis of the interlinked damage to economic activities and infrastructure in the Severn floods of 2007 in the UK. Besides investigating the usability of existing data, this research investigated: (i the relative weight of direct and indirect costs to business and infrastructure companies; (ii to what extent damage to infrastructure has impacted on indirect damage to businesses. Finally recommendations for improving the data for use in forensic investigation are offered.

  11. Compilation of radiation damage test data. Pt. 3

    International Nuclear Information System (INIS)

    Beynel, P.; Maier, P.; Schoenbacher, H.

    1982-01-01

    This handbook gives the results of radiation damage tests on various engineering materials and components intended for installation in radiation areas of the CERN high-energy particle accelerators. It complements two previous volumes covering organic cable-insulating materials and thermoplastic and thermosetting resins. The irradiation have been carried out at various radiation sources and the results of the different tests are reported, sometimes illustrated by tables and graphs to show the variation of the measured property with absorbed radiation dose. For each entry, an appreciation of the radiation resistance is given, based on measurement data, indicating the range of damage (moderate to severe) for doses from 10 to 10 8 Gy. Also included are tables, selected from published reports, of general relative radiation effects for several groups of materials, to which there are systematic cross-references in the alphabetical part. This third and last volume contains cross-references to all the materials presented up to now, so that it can be used as a guide to the three volumes. (orig.)

  12. Radiation damage in natural materials: implications for radioactive waste forms

    International Nuclear Information System (INIS)

    Ewing, R.C.

    1981-01-01

    The long-term effect of radiation damage on waste forms, either crystalline or glass, is a factor in the evaluation of the integrity of waste disposal mediums. Natural analogs, such as metamict minerals, provide one approach for the evaluaton of radiation damage effects that might be observed in crystalline waste forms, such as supercalcine or synroc. Metamict minerals are a special class of amorphous materials which were initially crystalline. Although the mechanism for the loss of crystallinity in these minerals (mostly actinide-containing oxides and silicates) is not clearly understood, damage caused by alpha particles and recoil nuclei is critical to the metamictization process. The study of metamict minerals allows the evaluation of long-term radiation damage effects, particularly changes in physical and chemical properties such as microfracturing, hydrothermal alteration, and solubility. In addition, structures susceptible to metamictization share some common properties: (1) complex compositions; (2) some degree of covalent bonding, instead of being ionic close-packed MO/sub x/ structures; and (3) channels or interstitial voids which may accommodate displaced atoms or absorbed water. On the basis of these empirical criteria, minerals such as pollucite, sodalite, nepheline and leucite warrant careful scrutiny as potential waste form phases. Phases with the monazite or fluorite structures are excellent candidates

  13. Analyses of the Secondary Particle Radiation and the DNA Damage it Causes to Human Keratinocytes

    Energy Technology Data Exchange (ETDEWEB)

    Lebel E. A.; Tafrov S.; Rusek, A.; Sivertz, M. B.; Yip, K.; Thompson, K. H.

    2011-11-01

    High-energy protons, and high mass and energy ions, along with the secondary particles they produce, are the main contributors to the radiation hazard during space explorations. Skin, particularly the epidermis, consisting mainly of keratinocytes with potential for proliferation and malignant transformation, absorbs the majority of the radiation dose. Therefore, we used normal human keratinocytes to investigate and quantify the DNA damage caused by secondary radiation. Its manifestation depends on the presence of retinol in the serum-free media, and is regulated by phosphatidylinositol 3-kinases. We simulated the generation of secondary radiation after the impact of protons and iron ions on an aluminum shield. We also measured the intensity and the type of the resulting secondary particles at two sample locations; our findings agreed well with our predictions. We showed that secondary particles inflict DNA damage to different extents, depending on the type of primary radiation. Low-energy protons produce fewer secondary particles and cause less DNA damage than do high-energy protons. However, both generate fewer secondary particles and inflict less DNA damage than do high mass and energy ions. The majority of cells repaired the initial damage, as denoted by the presence of 53BPI foci, within the first 24 hours after exposure, but some cells maintained the 53BP1 foci longer.

  14. Multiscale approach to the physics of radiation damage with ions

    International Nuclear Information System (INIS)

    Surdutovich, E.; Solov'yov, A.

    2014-01-01

    The multiscale approach to the assessment of bio-damage resulting upon irradiation of biological media with ions is reviewed, explained and compared to other approaches. The processes of ion propagation in the medium concurrent with ionization and excitation of molecules, transport of secondary products, dynamics of the medium, and biological damage take place on a number of different temporal, spatial and energy scales. The multiscale approach, a physical phenomenon-based analysis of the scenario that leads to radiation damage, has been designed to consider all relevant effects on a variety of scales and develop an approach to the quantitative assessment of biological damage as a result of irradiation with ions. Presently, physical and chemical effects are included in the scenario while the biological effects such as DNA repair are only mentioned. This paper explains the scenario of radiation damage with ions, overviews its major parts, and applies the multiscale approach to different experimental conditions. On the basis of this experience, the recipe for application of the multiscale approach is formulated. The recipe leads to the calculation of relative biological effectiveness. (authors)

  15. Positron annihilation lifetime study of radiation-damaged natural zircons

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, J. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra (Australia); Gaugliardo, P. [Centre for Antimatter-Matter Studies, School of Physics, University of Western Australia (Australia); Farnan, I.; Zhang, M. [Department of Earth Sciences, University of Cambridge (United Kingdom); Vance, E.R.; Davis, J.; Karatchevtseva, I.; Knott, R.B. [Australian Nuclear Science and Technology Organisation (Australia); Mudie, S. [The Australian Synchrotron, Victoria (Australia); Buckman, S.J. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra (Australia); Institute for Mathematical Sciences, University of Malaya, Kuala Lumpur (Malaysia); Sullivan, J.P., E-mail: james.sullivan@anu.edu.au [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra (Australia)

    2016-04-01

    Zircons are a well-known candidate waste form for actinides and their radiation damage behaviour has been widely studied by a range of techniques. In this study, well-characterised natural single crystal zircons have been studied using Positron Annihilation Lifetime Spectroscopy (PALS). In some, but not all, of the crystals that had incurred at least half of the alpha-event damage of ∼10{sup 19} α/g required to render them structurally amorphous, PALS spectra displayed long lifetimes corresponding to voids of ∼0.5 nm in diameter. The long lifetimes corresponded to expectations from published Small-Angle X-ray Scattering data on similar samples. However, the non-observation by PALS of such voids in some of the heavily damaged samples may reflect large size variations among the voids such that no singular size can be distinguished or. Characterisation of a range of samples was also performed using scanning electron microscopy, optical absorption spectroscopy, Raman scattering and X-ray scattering/diffraction, with the degree of alpha damage being inferred mainly from the Raman technique and X-ray diffraction. The observed void diameters and intensities of the long lifetime components were changed somewhat by annealing at 700 °C; annealing at 1200 °C removed the voids entirely. The voids themselves may derive from He gas bubbles or voids created by the inclusion of small quantities of organic and hydrous matter, notwithstanding the observation that no voidage was evidenced by PALS in two samples containing hydrous and organic matter. - Highlights: • Study of a range of naturally occurring zircons damaged by alpha radiation. • Characterised using a range of techniques, including PALS spectroscopy. • Effects on hydrous material appear important, rather than direct radiation damage. • Annealing is shown to remove the observed voids.

  16. Radiation-induced Pulmonary Damage in Lung Cancer Patients

    International Nuclear Information System (INIS)

    Chung, Su Mi; Choi, Ihl Bohng; Kang, Mi Mun; Kim, In Ah; Shinn, Kyung Sub

    1993-01-01

    Purpose: A retrospective analysis was performed to evaluate the incidence of radiation induced lung damage after the radiation therapy for the patients with carcinoma of the lung. Method and Materials: Sixty-six patients with lung cancer (squamous cell carcinoma 27, adenocarcinoma 14, large cell carcinoma 2, small cell carcinoma 13, unknown 10) were treated with definitive, postoperative or palliative radiation therapy with or without chemotherapy between July 1987 and December 1991. There were 50 males and 16 females with median age of 63 years(range: 33-80 years). Total lung doses ranged from 500 to 6,660 cGy (median 3960 cGy) given in 2 to 38 fractions (median 20) over a range of 2 to 150 days (median 40 days) using 6 MV or 15 MV linear accelerator. To represent different fractionation schedules of equivalent biological effect, the estimated single dose(ED) model, ED=D·N-0.377·T-0.058 was used in which D was the lung dose in cGy, N was the number of fractions, and T was the overall treatment time in days. The range of ED was 370 to 1357. The endpoint was a visible increase in lung density within the irradiated volume on chest X-ray as observed independently by three diagnostic radiologists. Patients were grouped according to ED, treatment duration, treatment modality and age, and the percent incidence of pulmonary damage for each group was determined. Result: In 40 of 66 patients, radiation induced change was seen on chest radiographs between 11 days and 314 days after initiation of radiation therapy. The incidence of radiation pneumonitis was increased according to increased ED, which was statistically significant (p=0.001). Roentgenographic charges consistent with radiation pneumonitis were seen in 100% of patients receiving radiotherapy after lobectomy or pneumonectomy, which was not statistically significant. In 32 patients who also received chemotherapy, there was no difference in the incidence of radiation induced charge between the group with radiation

  17. Monitoring radiation damage in the ATLAS pixel detector

    CERN Document Server

    Schorlemmer, André Lukas; Quadt, Arnulf; Große-Knetter, Jörn; Rembser, Christoph; Di Girolamo, Beniamino

    2014-11-05

    Radiation hardness is one of the most important features of the ATLAS pixel detector in order to ensure a good performance and a long lifetime. Monitoring of radiation damage is crucial in order to assess and predict the expected performance of the detector. Key values for the assessment of radiation damage in silicon, such as the depletion voltage and depletion depth in the sensors, are measured on a regular basis during operations. This thesis summarises the monitoring program that is conducted in order to assess the impact of radiation damage and compares it to model predictions. In addition, the physics performance of the ATLAS detector highly depends on the amount of disabled modules in the ATLAS pixel detector. A worrying amount of module failures was observed during run I. Thus it was decided to recover repairable modules during the long shutdown (LS1) by extracting the pixel detector. The impact of the module repairs and module failures on the detector performance is analysed in this thesis.

  18. Radiation damage in CaF2: Gd

    International Nuclear Information System (INIS)

    Prado, L.

    1979-01-01

    Calcium fluoride crystals doped with Gd 3+ at four different concentrations were irradiated at room temperature. The damage produced by radiation and the primary and secondary effects as well were studied by optical spectroscopy. The increase in optical absorption (with loss of transparency) varied from sample as a function of concentration and dose. The coloration curves showed an evolution from two to three radiation damage steps when going from a pure to the most Gd 3+ concentrated sample. The obtained spectra were analysed at characteristic wave lenghts of electronic defects (photochromic centers, F and its aggregates) and of Gd 3+ and Gd 2+ defects. As a result of the radiation damage the valence change (Gd 3+ →Gd 2+ ) and its reversible character under thermal activation were directly observed. These effects were correlated with other observed effects such as the room temperature luminescence after the irradiation ceased. The non radiative F centers formation from the interaction of holes and photochromic centers was also observed and analysed. A thermal activation study of the several defects responsible for the different absorption bands was made. Values of activation energies were obtained as expected for the kind of defects involved in these processes [pt

  19. Laser annealing heals radiation damage in avalanche photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jin Gyu [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); Anisimova, Elena; Higgins, Brendon L.; Bourgoin, Jean-Philippe [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Jennewein, Thomas [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Canadian Institute for Advanced Research, Quantum Information Science Program, Toronto, ON (Canada); Makarov, Vadim [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada)

    2017-12-15

    Avalanche photodiodes (APDs) are a practical option for space-based quantum communications requiring single-photon detection. However, radiation damage to APDs significantly increases their dark count rates and thus reduces their useful lifetimes in orbit. We show that high-power laser annealing of irradiated APDs of three different models (Excelitas C30902SH, Excelitas SLiK, and Laser Components SAP500S2) heals the radiation damage and several APDs are restored to typical pre-radiation dark count rates. Of nine samples we test, six APDs were thermally annealed in a previous experiment as another solution to mitigate the radiation damage. Laser annealing reduces the dark count rates further in all samples with the maximum dark count rate reduction factor varying between 5.3 and 758 when operating at -80 C. This indicates that laser annealing is a more effective method than thermal annealing. The illumination power to reach these reduction factors ranges from 0.8 to 1.6 W. Other photon detection characteristics, such as photon detection efficiency, timing jitter, and afterpulsing probability, fluctuate but the overall performance of quantum communications should be largely unaffected by these variations. These results herald a promising method to extend the lifetime of a quantum satellite equipped with APDs. (orig.)

  20. Primary radiation damage and disturbance in cell divisions

    International Nuclear Information System (INIS)

    Kim, Jin Kyu; Lee, Yun-Jong; Kim, Jae-Hun; Petin, Vladislav G.; Nili, Mohammad

    2008-01-01

    Survived cells from a homogeneous population exposed to ionizing radiation form various colonies of different sizes and morphology on a solid nutrient medium, which appear at different time intervals after irradiation. Such a phenomenon agrees well with the modern theory of microdosimetry and classical hit-and-target models of radiobiology. According to the hit-principle, individual cells exposed to the same dose of radiation are damaged in different manners. It means that the survived cells can differ in the content of sublethal damage (hits) produced by the energy absorbed into the cell and which is not enough to give rise to effective radiation damage which is responsible for cell killing or inactivation. In diploid yeast cells, the growth rate of cells from 250 colonies of various sizes appeared at different time intervals after irradiation with 600 Gy of gamma radiation from a 60 Co isotopic source was analyzed. The survival rate after irradiation was 20%. Based on the analyses results, it was possible to categorize the clones grown from irradiated cells according to the number of sub-lesions from 1 to 4. The clones with various numbers of sub-lesions were shown to be different in their viability, radiosensitivity, sensitivity to environmental conditions, and the frequency of recombination and respiratory deficient mutations. Cells from unstable clones exhibited an enhanced radiosensitivity, and an increased portion of morphologically changed cells, nonviable cells and respiration mutants, as well. The degree of expression of the foregoing effects was higher if the number of primary sublethal lesions was greater in the originally irradiated cell. Disturbance in cell division can be characterized by cell inactivation or incorrect distribution of mitochondria between daughter cells. Thus, the suggested methodology of identification of cells with a definite number of primary sublethal lesions will promote further elucidation of the nature of primary radiation

  1. Electron Microscopy Study of Stainless Steel Radiation Damage Due to Long-Term Irradation by Alpha Particles Emitted From Plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Unlu, Kenan [Univ. of Texas, Austin, TX (United States); Rios-Martinez, Carlos [Univ. of Texas, Austin, TX (United States); Saglam, Mehmet [Univ. of Texas, Austin, TX (United States); Hart, Ron R. [Texas A & M Univ., College Station, TX (United States); Shipp, John D. [Texas A & M Univ., College Station, TX (United States); Rennie, John [Texas A & M Univ., College Station, TX (United States)

    1998-04-16

    Radiation damage and associated surface and microstructural changes produced in stainless steel encapsulation by high-fluence alpha particle irradiations from weapons-grade plutonium of 316-stainless steel are being investigated.

  2. Consequential late radiation damage in the skin in nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Li Wei; Kong Ling; Zhang Youwang; Hu Chaosu; Wu Yongru

    2008-01-01

    Objective: To evaluate the relationship between early and late radiation damage in skin. Methods: 335 patients with nasopharyngeal carcinoma treated with radical radiotherapy were evaluated. 240 patients had lymph nodes in the neck at initial diagnosis. The median doses were 70 Gy (55-86 Gy) to the nasopharyngeal region by external beam radiotherapy. The median doses were 64 Gy (46-72 Gy) to the neck with lymph node metastases, 55 Gy (21-67 Gy) to the node-negative neck. 71 patients were treated with facial-neck fields, while 264 patients were treated with pre-auricular fields. Chemotherapy was given in 48 patients. According to the 1995 SOMA scales late radiation damage in the skin was evaluated. Results: The median time from the radiotherapy to follow up was 14 years (range, 5-38 years). 63 patients have grade 0 late radiation reactions in the neck skin, the grade 1,2, 3,4 late radiation reactions in the neck skin were 43.9% (147 patients), 20.9% (70 patients), 13.7% (46 patients) and 2.7% (9 patients), respectively. 44 patients had moist desquamation in the medical records. The grade 1,2,3,4 late radiation reactions in the neck skin were 41%, 23%, 30% and 5%, respectively in patients with moist desquamation, while in patients without moist desquamation, the corresponding rates were 44.3%, 20.6%, 11.3% and 2.4%, respectively. The difference were significant between these two groups by chi-square analysis(χ 2 =17.42, P=0.002). Furthermore, whether patients had positive lymph node in the neck or not, the size of facial-neck fields and higher doses to the neck had more severe late radiation reaction in the neck skin, while age, gender and chemotherapy failed to show any effects on the development of late radiation reactions in the neck skin. Conclusion: The severe early radiation damage in the skin possibly increases the late radiation damage in the neck skin. (authors)

  3. Feasibility of OCT to detect radiation-induced esophageal damage in small animal models (Conference Presentation)

    Science.gov (United States)

    Jelvehgaran, Pouya; Alderliesten, Tanja; Salguero, Javier; Borst, Gerben; Song, Ji-Ying; van Leeuwen, Ton G.; de Boer, Johannes F.; de Bruin, Daniel M.; van Herk, Marcel B.

    2016-03-01

    Lung cancer survival is poor and radiotherapy patients often suffer serious treatment side effects. The esophagus is particularly sensitive leading to reduced food intake or even fistula formation. Only few direct techniques exist to measure radiation-induced esophageal damage, for which knowledge is needed to improve the balance between risk of tumor recurrence and complications. Optical coherence tomography (OCT) is a minimally-invasive imaging technique that obtains cross-sectional, high-resolution (1-10µm) images and is capable of scanning the esophageal wall up to 2-3mm depth. In this study we investigated the feasibility of OCT to detect esophageal radiation damage in mice. In total 30 mice were included in 4 study groups (1 main and 3 control groups). Mice underwent cone-beam CT imaging for initial setup assessment and dose planning followed by single-fraction dose delivery of 4, 10, 16, and 20Gy on 5mm spots, spaced 10mm apart. Mice were repeatedly imaged using OCT: pre-irradiation and up to 3 months post-irradiation. The control groups received either OCT only, irradiation only, or were sham-operated. We used histopathology as gold standard for radiation-induced damage diagnosis. The study showed edema in both the main and OCT-only groups. Furthermore, radiation-induced damage was primarily found in the highest dose region (distal esophagus). Based on the histopathology reports we were able to identify the radiation-induced damage in the OCT images as a change in tissue scattering related to the type of induced damage. This finding indicates the feasibility and thereby the potentially promising role of OCT in radiation-induced esophageal damage assessment.

  4. Measuring Radiation Damage from Heavy Energetic Ions in Aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Kostin, M., PI-MSU; Ronningen, R., PI-MSU; Ahle, L., PI-LLNL; Gabriel, T., Scientific Investigation and Development; Mansur, L., PI-ORNL; Leonard, K., ORNL; Mokhov, N., FNAL; Niita, K., RIST, Japan

    2009-02-21

    An intense beam of 122 MeV/u (9.3 GeV) 76Ge ions was stopped in aluminum samples at the Coupled Cyclotron Facility at NSCL, MSU. Attempts were made at ORNL to measure changes in material properties by measuring changes in electrical resistivity and microhardness, and by transmission electron microscopy characterization, for defect density caused by radiation damage, as a function of depth and integrated ion flux. These measurements are relevant for estimating damage to components at a rare isotope beam facility.

  5. Study of radiation damage in metals by positron annihilation

    International Nuclear Information System (INIS)

    Gauster, W.B.

    1977-01-01

    Positron annihilation is a sensitive technique for probing defects in metals and it has recently been shown to be a valuable tool for the study of radiation damage. After an introduction to the three basic experimental methods (angular correlation, Doppler broadening, and lifetime measurements), the interaction of positrons with lattice defects is reviewed. Results for the annealing of damage after low temperature irradiation are used to show that positron annihilation has provided new information on annealing kinetics. The role of positron techniques in characterizing complex defect structures resulting from high-temperature neutron irradiation is reviewed and the possible utility of positron annihilation as a nondestructive monitor of property changes is pointed out

  6. Genetic damage from low-level and natural background radiation

    International Nuclear Information System (INIS)

    Oftedal, P.

    1988-01-01

    Relevant predictions that have been made of possible low level biological effects on man are reviewed, and the estimate of genetic damage is discussed. It is concluded that in spite of a number of attempts, no clear-cut case of effects in human populations of radiation at natural levels has been demonstrated. The stability of genetic material is dynamic, with damage, repair and selection running as continuous processes. Genetic materials are well protected and are conservative in the extreme, not least because evolution by genetic adaptation is an expensive process: Substitution of one allele A 1 by another A 2 means the death of the whole A 1 population

  7. Development and anneal of radiation damage in salt

    International Nuclear Information System (INIS)

    Garcia Celma, A.; Donker, H.; Soppe, W.J.; Miralles, L.

    1993-12-01

    Laboratory gamma-irradiations at a constant temperature (100 C) were carried out in two sorts of experiments, one at variable and another at approximately constant dose rates. The damage developed during irradiation was analyzed by thermal analysis, microstructural analysis and small angle neutron scattering. The results were compared with the yields of the Jain-Lidiard model for each experiment. Experiments at a constant dose rate were planned to obtain information on radiation damage development and anneal in conditions as near as possible to those of radioactive waste repository concepts. For this reason the dose rates were kept low. (orig./DG)

  8. Depth distributions of DNA damage in Antarctic marine phyto- and bacterioplankton exposed to summertime UV radiation

    NARCIS (Netherlands)

    Buma, A.G.J.; de Boer, M.K.; Boelen, P.

    During a survey from January to March 1998, the occurrence of W-B radiation (UVBR)-induced DNA damage in Antarctic marine phytoplankton and bacterioplankton was investigated, Sampling was done in Ryder Bay, off the British base Rothera Station, 67 degreesS, 68 degreesW (British Antarctic Survey).

  9. Modification of radiation-induced oxidative damage in liposomal and microsomal membrane by eugenol

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, B.N. [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Lathika, K.M. [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Mishra, K.P. [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)]. E-mail: kpm@magnum.barc.ernet.in

    2006-03-15

    Radiation-induced membrane oxidative damage, and their modification by eugenol, a natural antioxidant, was investigated in liposomes and microsomes. Liposomes prepared with DPH showed decrease in fluorescence after {gamma}-irradiation, which was prevented significantly by eugenol and correlated with magnitude of oxidation of phospholipids. Presence of eugenol resulted in substantial inhibition in MDA formation in irradiated liposomes/microsomes, which was less effective when added after irradiation. Similarly, the increase in phospholipase C activity observed after irradiation in microsomes was inhibited in samples pre-treated with eugenol. Results suggest association of radio- oxidative membrane damage with alterations in signaling molecules, and eugenol significantly prevented these membrane damaging events.

  10. Chromatin damage induced by fast neutrons or UV laser radiation

    Energy Technology Data Exchange (ETDEWEB)

    Radu, L.; Constantinescu, B.; Gazdaru, D.; Mihailescu, I

    2002-07-01

    Chromatin samples from livers of Wistar rats were subjected to fast neutron irradiation in doses of 10-100 Gy or to a 248 nm excimer laser radiation, in doses of 0.5-3 MJ.m{sup -2}. The action of the radiation on chromatin was monitored by chromatin intrinsic fluorescence and fluorescence lifetimes (of bound ethidium bromide to chromatin) and by analysing fluorescence resonance energy transfer between dansyl chloride and acridine orange coupled to chromatin. For the mentioned doses of UV excimer laser radiation, the action on chromatin was more intense than in the case of fast neutrons. The same types of damage are produced by the two radiations: acidic and basic destruction of chromatin protein structure, DNA strand breaking and the increase of the distance between DNA and proteins in chromatin. (author)

  11. Chromatin damage induced by fast neutrons or UV laser radiation

    International Nuclear Information System (INIS)

    Radu, L.; Constantinescu, B.; Gazdaru, D.; Mihailescu, I.

    2002-01-01

    Chromatin samples from livers of Wistar rats were subjected to fast neutron irradiation in doses of 10-100 Gy or to a 248 nm excimer laser radiation, in doses of 0.5-3 MJ.m -2 . The action of the radiation on chromatin was monitored by chromatin intrinsic fluorescence and fluorescence lifetimes (of bound ethidium bromide to chromatin) and by analysing fluorescence resonance energy transfer between dansyl chloride and acridine orange coupled to chromatin. For the mentioned doses of UV excimer laser radiation, the action on chromatin was more intense than in the case of fast neutrons. The same types of damage are produced by the two radiations: acidic and basic destruction of chromatin protein structure, DNA strand breaking and the increase of the distance between DNA and proteins in chromatin. (author)

  12. [Cellphone electromagnetic radiation damages the testicular ultrastructure of male rats].

    Science.gov (United States)

    Gao, Xiao-Hui; Hu, Hui-Rong; Ma, Xue-Lian; Chen, Jie; Zhang, Guo-Hong

    2016-06-01

    To investigate the influence of cellphone electromagnetic radiation (CER) on the testicular ultrastructure and the apoptosis of spermatogenic cells in male rats.atability, feasibility, applicability, and controllability in the construction of experimental animal models, we compared the major anatomic features of the penis of 20 adult beagle dogs with those of 10 adult men. Using microsurgical techniques, we performed cross-transplantation of the penis in the 20 (10 pairs) beagle dogs and observed the survival rate of the transplanted penises by FK506+MMF+MP immune induction. We compared the relevant indexes with those of the 10 cases of microsurgical replantation of the amputated penis. Thirty adult male SD rats were equally randomized into a 2 h CER, a 4 h CER, and a normal control group, the former two groups exposed to 30 days of 900 MHz CER for 2 and 4 hours a day, respectively, while the latter left untreated. Then the changes in the ultrastructure of the testis tissue were observed under the transmission electron microscope and the apoptosis of the spermatogenic cells was determined by TUNEL. Compared with the normal controls, the rats of the 2 h CER group showed swollen basement membrane of seminiferous tubules, separated tight junction of Sertoli cells, increased cell intervals, apparent vacuoles and medullization in some mitochondria, and increased apoptosis of spermatogenic cells, mainly the apoptosis of primary spermatocytes (P<0.05 ). In comparison with the 2 h CER group, the animals of the 4 h CER group exhibited swollen basement membrane of seminiferous tubules, more separated tight junction of Sertoli cells, wider cell intervals, incomplete membrane of spermatogonial cells, fragments of cytoplasm, nuclear pyknosis and notch, slight dilation of perinuclear space, abnormalities of intracellular mitochondria with vacuoles, fuzzy structure, and fusion or disappearance of some cristae, and increased damage of mitochondria and apoptosis of spermatogenic

  13. Umbelliferone suppresses radiation induced DNA damage and apoptosis in hematopoietic cells of mice

    International Nuclear Information System (INIS)

    Jayakumar, S.; Bhilwade, H.N.; Chaubey, R.C.

    2012-01-01

    Radiotherapy is one of the major modes of treatment for different types of cancers. But the success of radiotherapy is limited by injury to the normal cells. Protection of the normal cells from radiation damage by radioprotectors can increase therapeutic efficiency. These radioprotectors can also be used during nuclear emergency situations. Umbelliferone (UMB) is a wide spread natural product of the coumarin family. It occurs in many plants from the Apiaceae family. In the present study radioprotective effect of UMB was investigated in vitro and in vivo. Anti genotoxic effect of Umbelliferone was tested by treating the splenic lymphocytes with various doses of UMB (6.5 μM - 50 μM) prior to radiation (6Gy) exposure. After the radiation exposure, extent of DNA damage was assessed by comet assay at 5 mm and two hours after radiation exposure. At both the time points, it was observed that the pretreatment of UMB reduced the radiation induced DNA damage to a significant extent in comparison to radiation control. UMB pretreatment also significantly reduced the radiation induced apoptosis enumerated by propidium iodide staining assay. Results of clonogenic survival assay using intestinal cell line showed that pretreatment with UMB significantly protected against radiation induced loss of colony forming units. To assess the anti genotoxic role of umbelliferone in vivo two different doses of UMB (20 mg/Kg and 40 mg/Kg of body weight) were injected into Swiss mice or with vehicle and exposed to radiation. Thirty minutes after the radiation comet assay was performed in peripheral leukocytes. Frequency of micro nucleated erythrocytes was scored in bone marrow cells. It was observed that UMB alone did not cause any significant increase in DNA damage in comparison to control. Animals which are exposed to radiation alone showed significant increase in DNA damage and micronuclei frequency. But animals treated with UMB prior to the radiation exposure showed significant decrease

  14. Protection from ionizing radiation induced damages by phytoceuticals and nutraceuticals

    International Nuclear Information System (INIS)

    Nair, C.K.K.

    2012-01-01

    Exposure of living systems to ionizing radiation cause a variety of damages to DNA and membranes due to generation of free radicals and reactive oxygen species. The radiation induced lesions in the cellular DNA are mainly strand breaks, damage to sugar moiety, alterations and elimination of bases, cross links of the intra and inter strand type and cross links to proteins while peroxidation of the lipids and oxidation of proteins constitute the major lesions in the membranes. The radioprotectors elicit their action by various mechanisms such as i) by suppressing the formation of reactive species, ii) detoxification of radiation induced species, iii) target stabilization and iv) enhancing the repair and recovery processes. The radioprotective compounds are of importance in medical, industrial, environmental, military and space science applications. Radiation protection might offer a tactical advantage on the battlefield in the event of a nuclear warfare. Radioprotectors might reduce the cancer risk to populations exposed to radiations directly or indirectly through industrial and military applications. The antioxidant and radioprotective properties a few of these agents under in vitro and in vivo conditions in animal models will be discussed

  15. Radiation damage studies of detector-compatible Si JFETs

    International Nuclear Information System (INIS)

    Dalla Betta, Gian-Franco; Boscardin, Maurizio; Candelori, Andrea; Pancheri, Lucio; Piemonte, Claudio; Ratti, Lodovico; Zorzi, Nicola

    2007-01-01

    We have largely improved the performance of our detector-compatible Si JFETs by optimizing the fabrication technology. New devices feature thermal noise values close to the theoretical ones, and remarkably low 1/f noise figures. In view of adopting these JFETs for X-ray imaging and HEP applications, bulk and surface radiation damage tests have been carried out by irradiating single transistors and test structures with neutrons and X-rays. Selected results from static and noise characterization of irradiated devices are discussed in this paper, and the impact of radiation effects on the performance of JFET-based circuits is addressed

  16. Radiation damage and induced tetraploidy in mulberry (Morus alba L.)

    International Nuclear Information System (INIS)

    Katagiri, K.

    1976-01-01

    Vigorously growing mulberry shoots were exposed to 5 kR of gamma rays at the rate of 0.2 kR/hr and 5.0 kR/hr and successively pruned three times in two growing seasons. The most radiosensitive part of both the apical and axillary meristems was the second cell layer. The younger axillary bud primordia were more sensitive to radiation then the older ones. Recovery from radiation damage was assumed to be from the flank meristem in the shoot apex. The frequency of mutations was much lower than that of tetraploidy. Among the tetraploids 50% were 2-4-4 chimeras. (author)

  17. Prediction of radiation-related small-bowel damage

    International Nuclear Information System (INIS)

    Potish, R.A.

    1980-01-01

    In order to predict which patients have a high risk for radiation-related small-bowel damage, the concept of the dose-response curve was applied to the predisposing factors (number of previous laparotomies, extent of surgery, thin physique, hypertension, age, cancer stage, number of treatment days, fractionation, and weight change during radiotherapy) present in 92 patients receiving identical radiation doses and volumes This analysis allows an estimate of the probability of complication to be assigned to individual patients. The utility and limitations of the dose-response concept are discussed

  18. Influence of radiation damage on internal friction background

    International Nuclear Information System (INIS)

    Burbelo, R.M.; Grinik, Eh.U.; Paliokha, M.I.; Orlinskij, A.B.

    1984-01-01

    Influence of radiation damage on internal friction background in samples of polycrystalline nickel and iron irradiated by a fast neutron flux approximately 10 14 neutr/(cm 2 xs) at 350 deg C has been studied using the low-frequency unit of the reverse torsion pendulum type. It has been established experimentally that a high-temperature background of internal friction of iron and nickel samples decreases as accumulating radiation defects occurring under neutron irradiation. Assumptions on a possible mechanism of the effect have been proposed. Simple expression for the background magnitude evaluation has been suggested

  19. Radiation damage measurements on CZT drift strip detectors

    DEFF Research Database (Denmark)

    Kuvvetli, Irfan; Budtz-Jørgensen, Carl; Korsbech, Uffe C C

    2003-01-01

    from 2 x 10(8) to 60 x 10(8) p(+)/cm(2). Even for the highest fluences, which had a dramatic effect on the spectroscopic performance, we were able to recover the detectors after an appropriate annealing procedure. The radiation damage was studied as a function of depth inside the detector material...... with the proton dose. The radiation contribution to the electron trapping was found to obey the following relation: (mutau(e)(-1))(rad) = (2.5+/-0.2) x 10(-7) x Phi (V/cm)(2) with the proton fluence, Phi in p(+)/cm(2). The trapping depth dependence, however, did not agree well with the damage profile calculated...

  20. Intensification of ultraviolet-induced dermal damage by infrared radiation

    International Nuclear Information System (INIS)

    Kligman, L.H.

    1982-01-01

    To assess the role of IR in actinic damage to the dermis, albino guinea pigs were irradiated for 45 weeks with UV-B and UV-A, with and without IR. Control animals received IR only or no irradiation at all. Unirradiated dermis contains small amounts of elastic fibers in the upper dermis with greater depositions around follicles and sebaceous glands. After irradiation with UV, the fibers became more numerous, thicker, and more twisted; IR alone producd many fine, feathery fibers. The addition of IR to UV resulted in dense matlike elastic fiber depositions that exceeded what was observed with either irradiation alone. In combination or alone UV and IR radiation produced a large increase in ground substance, a finding also seen in actinically damaged human skin. Infrared radiation, in the physiologic range, though pleasant is not innocuous. (orig./MG) [de

  1. Mexamine used to decrease radiation damage to Wistar rat embryogenesis

    International Nuclear Information System (INIS)

    Palyga, G.F.; Zakoshchikov, K.F.

    1987-01-01

    In experiments with 330 Wistar rats experiencing their pregnancy and 1430 neonatal rats of the first generation a study was made on the toxicity and radioprotective efficiency of a single subcutaneous injection of 10 mg/kg mexamine on days 3, 11 and 19 pregnancy. The agent caused various abnormalities in pregnancy, delivery and postnatal development of the offspring of nonirradiated animals, and it was almost ineffective when used for the prevention of radiation damages during the anrnatal ontogenesis

  2. Effect of radiation damage on the infrared properties of apatite

    International Nuclear Information System (INIS)

    Anis Faridah Md Nori; Yusof Mohd Amin; Rosli Mahat; Burhanuddin Kamaluddin

    1991-01-01

    Apatites are known to contain radioactive elements such as uranium and thorium at a few ppm in concentration. These elements decay and produce fission tracks inside the crystals. The presence of such tracks have been known to affect the thermoluminescence (TL) properties of apatites. These fission tracks can be removed by annealing the crystals in air. In this paper we present the result of a preliminary study on the effect of radiation damage on the infrared transmission of apatites

  3. Reduction in thermal conductivity of ceramics due to radiation damage

    International Nuclear Information System (INIS)

    Klemens, P.G.; Hurley, G.F.; Clinard, F.W. Jr.

    1976-01-01

    Ceramics are required for a number of applications in fusion reactors. In several of these applications, the thermal conductivity is an important design parameter as it affects the level of temperature and thermal stress in service. Ceramic insulators are known to suffer substantial reduction in thermal conductivity due to neutron irradiation damage. The present study estimates the reduction in thermal conductivity at high temperature due to radiation induced defects. Point, extended, and extended partly transparent defects are considered

  4. Radiation damage status of the ATLAS silicon strip detectors (SCT)

    CERN Document Server

    Kondo, Takahiko; The ATLAS collaboration

    2017-01-01

    The Silicon microstrip detector system (SCT) of the ATLAS experiment at LHC has been working well for about 7 years since 2010. The innermost layer has already received a few times of 10**13 1-MeV neutron-equivalent fluences/cm2. The evolutions of the radiation damage effects on strip sensors such as leakage current and full depletion voltages will be presented.

  5. Ascorbic acid (AA) metabolism in protection against radiation damage

    International Nuclear Information System (INIS)

    Rose, R.C.; Koch, M.J.

    1986-01-01

    The possibility is considered that AA protects tissues against radiation damage by scavenging free radicals that result from radiolysis of water. A physiologic buffer (pH 6.7) was incubated with 14 C-AA and 1 mM thiourea (to slow spontaneous oxidation of AA). Aliquots were assayed by HPLC and scintillation spectrometry to identify the 14 C-label. Samples exposed to Cobalt-60 radiation had a half time of AA decay of 30 minutes) indicating that AA scavenges radiation-induced free radicals and forms the ascorbate free radical (AFR). Pairs of 14 C-AFR disproportionate, with the net effect of 14 C-dehydroascorbic acid formation from 14 C-AA. Having established that AFR result from ionizing radiation in an aqueous solution, the possibility was evaluated that a tissue factor reduces AFR. Cortical tissue from the kidneys of male rats was minced, homogenized in buffer and centrifuged at 8000 xg. The supernatant was found to slow the rate of radiation-induced AA degradation by > 90% when incubated at 23 0 C in the presence of 15 μM 14 C-AA. Samples of supernatant maintained at 100 0 C for 10 minutes or precipitated with 5% PCA did not prevent radiation-induced AA degradation. AA may have a specific role in scavenging free radicals generated by ionizing radiation and thereby protect body tissues

  6. Historical update of past and recent skin damage radiation accidents

    International Nuclear Information System (INIS)

    Lushbaugh, C.C.; Fry, S.A.; Ricks, R.C.; Hubner, K.F.; Burr, W.W.

    1986-01-01

    Records of radiation accidents worldwide since 1944 are maintained at the Radiation Accident Registry of the Radiation Emergency Assistance Center/Training Site (REAC/TS) in Oak Ridge. These records show that in 263 major radiation accidents there have been 150 severe local radiation injuries, of which 117 have been exposure to sealed radioactive sources. Most lesions resulted from the unsafe handling of 192 Ir radiography sources. Recent redesign of these devices, used for testing the integrity of welds, promises to eliminate these accidents. However, many other kinds of irradiators used in industry and scientific research still remain in the public domain, capable of causing irreparable dermal damage. Registry records reveal many unsolved physical and medical problems whose solution is urgently needed to improve the prognosis and therapy of such lesions. Pathologically, radiation-induced skin lesions are well described and an approximate dose-response relationship is univerally accepted even though the actual 'dose' is rarely known at first. Radiation dose is estimated biologically after the lesion has run its pathological course or after a medical physicist has prepared a retrospective 'mock-up' of the accident. (author)

  7. Radiobiology in clinical radiation therapy - Part III: Normal tissue damage

    International Nuclear Information System (INIS)

    Travis, Elizabeth L.

    1996-01-01

    Objective: This is the third part of a course designed for residents in radiation oncology preparing for their boards. This part of the course will focus on the mechanisms underlying damage in normal tissues. Although conventional wisdom long held that killing and depletion of a critical cell(s) in a tissue was responsible for the later expression of damage, histopathologic changes in normal tissue can now be explained and better understood in terms of the new molecular biology. The concept that depletion of a single cell type is responsible for the observed histopathologic changes in normal tissues has been replaced by the hypothesis that damage results from the interaction of many different cell systems, including epithelial, endothelial, macrophages and fibroblasts, via the production of specific autocrine, paracrine and endocrine growth factors. A portion of this course will discuss the clinical and experimental data on the production and interaction of those cytokines and cell systems considered to be critical to tissue damage. It had long been suggested that interindividual differences in radiation-induced normal tissue damage was genetically regulated, at least in part. Both clinical and experimental data supported this hypothesis but it is the recent advances in human and mouse molecular genetics which have provided the tools to dissect out the genetic component of normal tissue damage. These data will be presented and related to the potential to develop genetic markers to identify sensitive individuals. The impact on clinical outcome of the ability to identify prospectively sensitive patients will be discussed. Clinically it is well-accepted that the volume of tissue irradiated is a critical factor in determining tissue damage. A profusion of mathematical models for estimating dose-volume relationships in a number of organs have been published recently despite the fact that little data are available to support these models. This course will review the

  8. Investigating Undergraduate Students’ Conceptions of Radiation

    Science.gov (United States)

    Romine, James M.; Buxner, Sanlyn; Impey, Chris; Nieberding, Megan; Antonellis, Jessie C.

    2014-11-01

    Radiation is an essential topic to the physical sciences yet is often misunderstood by the general public. The last time most people have formal instruction about radiation is as students in high school and this knowledge will be carried into adulthood. Peoples’ conceptions of radiation influence their attitude towards research regarding radiation, radioactivity, and other work where radiation is prevalent. In order to understand students’ ideas about radiation after having left high school, we collected science surveys from nearly 12,000 undergraduates enrolled in introductory science courses over a span of 25 years. This research investigates the relationship between students’ conceptions of radiation and students’ personal beliefs and academic field of study.Our results show that many students in the sample were unable to adequately describe radiation. Responses were typically vague, brief, and emotionally driven. Students’ field of study was found to significantly correlate with their conceptions. Students pursuing STEM majors were 60% more likely to describe radiation as an emission and/or form of energy and cited atomic or radioactive sources of radiation twice as often as non-STEM students. Additionally, students’ personal beliefs also appear to relate to their conceptions of radiation. The most prominent misconception shown was that radiation is a generically harmful substance, which was found to be consistent throughout the duration of the study. In particular, non-science majors in our sample had higher rates of misconceptions, often generalized the idea of radiation into a broad singular topic, and had difficulty properly identifying sources.Generalized ideas of radiation and the inability to properly recognize sources of radiation may contribute to the prevalent misconception that radiation is an inexplicably dangerous substance. A basic understanding of both electromagnetic and particulate radiation and the existence of radiation at various

  9. Gamma radiation damage in pixelated detector based on carbon nanotubes

    International Nuclear Information System (INIS)

    Leyva, A.; Pinnera, I.; Leyva, D.; Abreu, Y.; Cruz, C. M.

    2013-01-01

    The aim of this paper is to evaluate the possible gamma radiation damage in high pixelated based on multi-walled carbon nanotubes detectors, grown on two different substrata, when it is operating in aggressive radiational environments. The radiation damage in displacements per atom (dpa) terms were calculated using the MCCM algorithm, which takes into account the McKinley-Feshbach approach with the Kinchin-Pease approximation for the damage function. Was observed that with increasing of the gamma energy the displacement total number grows monotonically reaching values of 0.39 displacements for a 10 MeV incident photon. The profiles of point defects distributions inside the carbon nanotube pixel linearly rise with depth, increasing its slope with photon energy. In the 0.1 MeV - 10 MeV studied energy interval the electron contribution to the total displacement number become higher than the positron ones, reaching this last one a maximum value of 12% for the 10 MeV incident photons. Differences between the calculation results for the two used different substrata were not observed. (Author)

  10. 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

  11. Acetylation dynamics of human nuclear proteins during the ionizing radiation-induced DNA damage response

    DEFF Research Database (Denmark)

    Bennetzen, Martin; Andersen, J.S.; Lasen, D.H.

    2013-01-01

    Genotoxic insults, such as ionizing radiation (IR), cause DNA damage that evokes a multifaceted cellular DNA damage response (DDR). DNA damage signaling events that control protein activity, subcellular localization, DNA binding, protein-protein interactions, etc. rely heavily on time...

  12. Recovery and permanent radiation damage of plastic scintillators at different dose rates

    International Nuclear Information System (INIS)

    Bicken, B.; Holm, U.; Marckmann, T.; Wick, K.; Rhode, M.

    1990-01-01

    This paper reports on the radiation stability of plastic scintillators and wavelength shifters for the calorimeter of the ZEUS detector by irradiating them with protons, a 60 Co-source, and depleted uranium. Changes in light yield, absorption length and absorption coefficient have been measured for storage in inert and oxygen atmospheres during and after irradiation. Radiation doses up to 40 kGy with dose rates of 30 up to 2000 Gy/h have been applied. The polystyrene based scintillator SCSN-38 and the wavelength shifters Y-7 and K-27 in PMMA show an additional absorption but a recovery in air to a low permanent damage (at 10 kGy) which is proportional to the applied dose. Series investigations on samples of all production cycles of the ZEUS scintillators with high dose rates show only minor differences in radiation hardness. The recovery is described by a simple oxygen diffusion model for high and medium dose rates down to 30 Gy/h. During long term irradiations at low dose rates (<100 Gy/h) of 3 mm thick SCSN-38 in air the radiation damage recovers to a permanent damage which does not depend on the dose rate. On the other hand the radiation damage at very low dose rates (17 Gy/a) seems to be higher than expected for the accumulated dose

  13. PUMN: part I of the WINERY radiation damage computer simulation system

    International Nuclear Information System (INIS)

    Kuspa, J.P.; Edwards, D.R.; Tsoulfanidis, N.

    1976-01-01

    Results of computer work to simulate the response of crystalline materials to radiation are presented. To organize this and future work into a long range program of investigation, the WINERY Radiation Damage Computer Simulation System is proposed. The WINERY system is designed to solve the entire radiation damage problem from the incident radiation to the property changes which occur in the material, using a set of interrelated computer programs. One portion of the system, the PUMN program, has been used to obtain important radiation damage results with Fe 3 Al crystal. PUMN simulates the response of the atoms in a crystal to a knock-on atom. It yields the damage configuration of the crystal by considering the dynamic interaction of all the atoms of the computational cell, up to 1000 atoms. The PUMN program provides the WINERY system with results for the number of displacements, N/sub d/, due to knock-on atoms with various energies. The values of N/sub d/ for Fe 3 Al were obtained at two different energies, 100 and 500 eV, for a variety of initial directions. These values are to be used to form a table of results for use in WINERY

  14. Experimental studies on radiation damages of CsI(Tl) crystals

    International Nuclear Information System (INIS)

    He Jingtang; Mao Yufang; Dong Xiaoli; Chen Duanbao; Li Zuhao

    1997-01-01

    The results of experimental studies on radiation damage of CsI(Tl) crystal were reported. There are radiation damage effects on CsI(Tl) crystal. Experimental studies on recovery of damaged CsI(Tl) crystals were made. It seems that after heating at 200 degree C for 4 hours, the damaged crystals could be recovered completely

  15. Clinical Investigation of Radiation Retinopathy Fundus and Fluorescein Angiographic Features

    Institute of Scientific and Technical Information of China (English)

    LiMei; QiuGT

    1999-01-01

    Purpose:To investigate the fundus and fluorescein angiographic features in the patients with radiation retinopathy.Clinical Materials:Color fundus photography and/or fluorescein angiography from 13 patients with nasopharyngeal carcinomas received external beam radiation were retrospectively analyzed.Reslts:In this study,26 damaged eyes of 13 patients eveloped some degree of radiation retinopathy.The earliest and most common finding was macular microvascular changes (microaneurysms and/or telangiectasia),which was observed in 100%(26/26)of the eyes.Intraretinal hemorrhages,macular capillary nonperfusion,and macular edema were noted in 84%,50%,and 42% of the eyes,respectively.Conclusions:Radiation retinopathy is common after external beam radiation of nasopharyngeal carcinomas.The prominent changes include maular microvascular changes,intraretinal hemorrhages and macular capillary nonperfusion.

  16. Chromatin modifications and the DNA damage response to ionizing radiation

    International Nuclear Information System (INIS)

    Kumar, Rakesh; Horikoshi, Nobuo; Singh, Mayank; Gupta, Arun; Misra, Hari S.; Albuquerque, Kevin; Hunt, Clayton R.; Pandita, Tej K.

    2013-01-01

    In order to survive, cells have evolved highly effective repair mechanisms to deal with the potentially lethal DNA damage produced by exposure to endogenous as well as exogenous agents. Ionizing radiation exposure induces highly lethal DNA damage, especially DNA double-strand breaks (DSBs), that is sensed by the cellular machinery and then subsequently repaired by either of two different DSB repair mechanisms: (1) non-homologous end joining, which re-ligates the broken ends of the DNA and (2) homologous recombination, that employs an undamaged identical DNA sequence as a template, to maintain the fidelity of DNA repair. Repair of DSBs must occur within the natural context of the cellular DNA which, along with specific proteins, is organized to form chromatin, the overall structure of which can impede DNA damage site access by repair proteins. The chromatin complex is a dynamic structure and is known to change as required for ongoing cellular processes such as gene transcription or DNA replication. Similarly, during the process of DNA damage sensing and repair, chromatin needs to undergo several changes in order to facilitate accessibility of the repair machinery. Cells utilize several factors to modify the chromatin in order to locally open up the structure to reveal the underlying DNA sequence but post-translational modification of the histone components is one of the primary mechanisms. In this review, we will summarize chromatin modifications by the respective chromatin modifying factors that occur during the DNA damage response.

  17. Radiation-induced neuropathies: collateral damage of improved cancer prognosis

    International Nuclear Information System (INIS)

    Pradat, Pierre-Francois; Maisonobe, Thierry; Psimaras, Dimitri; Lenglet, Timothee; Porcher, Raphael; Lefaix, J.L.; Delenian, S.

    2012-01-01

    Because of the improvement of cancer prognosis, long-term damages of treatments become a medical and public health problem. Among the iatrogenic complications, neurological impairment is crucial to consider since motor disability and pain have a considerable impact on quality of life of long cancer survivors. However, radiation-induced neuropathies have not been the focus of great attention. The objective of this paper is to provide an updated review about the radiation-induced lesions of the peripheral nerve system. Radiation-induced neuropathies are characterized by their heterogeneity in both symptoms and disease course. Signs and symptoms depend on the affected structures of the peripheral nerve system (nerve roots, nerve plexus or nerve trunks). Early-onset complications are often transient and late complications are usually progressive and associated with a poor prognosis. The most frequent and well known is delayed radiation-induced brachial plexopathy, which may follow breast cancer irradiation. Radiation-induced lumbosacral radiculoplexopathy is characterized by pure or predominant lower motor neuron signs. They can be misdiagnosed, confused with amyotrophic lateral sclerosis (ALS) or with leptomeningeal metastases since nodular MRI enhancement of the nerve roots of the cauda equina and increased cerebrospinal fluid protein content can be observed. In the absence of specific markers of the link with radiotherapy, the diagnosis of post-radiation neuropathy may be difficult. Recently, a posteriori conformal radiotherapy with 3D dosimetric reconstitution has been developed to link a precise anatomical site to unexpected excess irradiation. The importance of early diagnosis of radiation-induced neuropathies is underscored by the emergence of new disease-modifying treatments. Although the pathophysiology is not fully understood, it is already possible to target radiation-induced fibrosis but also associated factors such as ischemia, oxidative stress and

  18. Radiation damage and rate limitations in tracking devices

    International Nuclear Information System (INIS)

    Gilchriese, M.G.D.

    1984-01-01

    In this note the author briefly discusses radiation damage to wire chambers and silicon strip devices and the electronics that may be associated with each of these. Scintillating fibers and CCD's are not discussed although the former appears to be a potentially radiation-resistant detector. In order to calculate radiation levels and rates the author assumed the following: an inelastic cross section of 100 mb at the SSC - six charged particles per unit of rapidity - photons and neutrons do not contribute to the background (photon conversions are negligible with a thin Be beam pipe) - beam gas interactions and beam losses (except during injection when I assume that the detector is ''off'') are negligible. This is discussed in a later section. - 1 Rad = 3.5 x 10 7 minimum ionizing particlescm 2

  19. PREFACE: Radiation Damage in Biomolecular Systems (RADAM07)

    Science.gov (United States)

    McGuigan, Kevin G.

    2008-03-01

    The annual meeting of the COST P9 Action `Radiation damage in biomolecular systems' took place from 19-22 June 2007 in the Royal College of Surgeons in Ireland, in Dublin. The conference was structured into 5 Working Group sessions: Electrons and biomolecular interactions Ions and biomolecular interactions Radiation in physiological environments Theoretical developments for radiation damage Track structure in cells Each of the five working groups presented two sessions of invited talks. Professor Ron Chesser of Texas Tech University, USA gave a riveting plenary talk on `Mechanisms of Adaptive Radiation Responses in Mammals at Chernobyl' and the implications his work has on the Linear-No Threshold model of radiation damage. In addition, this was the first RADAM meeting to take place after the Alexander Litvenenko affair and we were fortunate to have one of the leading scientists involved in the European response Professor Herwig Paretzke of GSF-Institut für Strahlenschutz, Neuherberg, Germany, available to speak. The remaining contributions were presented in the poster session. A total of 72 scientific contributions (32 oral, 40 poster), presented by 97 participants from 22 different countries, gave an overview on the current progress in the 5 different subfields. A 1-day pre-conference `Early Researcher Tutorial Workshop' on the same topic kicked off on 19 June attended by more than 40 postgrads, postdocs and senior researchers. Twenty papers, based on these reports, are included in this volume of Journal of Physics: Conference Series. All the contributions in this volume were fully refereed, and they represent a sample of the courses, invited talks and contributed talks presented during RADAM07. The interdisciplinary RADAM07 conference brought together researchers from a variety of different fields with a common interest in biomolecular radiation damage. This is reflected by the disparate backgrounds of the authors of the papers presented in these proceedings

  20. Contribution of endogenous and exogenous damage to the total radiation-induced damage in the bacterial spore

    International Nuclear Information System (INIS)

    Jacobs, G.P.; Samuni, A.; Czapski, G.

    1980-01-01

    Radical scavengers such as polyethylene glycol 4000 and bovine albumin have been used to define the contribution of exogenous and endogenous damage to the total radiation-induced damage in aqueous buffered suspensions of Bacillus pumilus spores. The results indicate that this damage in the bacterial spore is predominantly endogenous

  1. Investigation of graphene-based nanoscale radiation sensitive materials

    Science.gov (United States)

    Robinson, Joshua A.; Wetherington, Maxwell; Hughes, Zachary; LaBella, Michael, III; Bresnehan, Michael

    2012-06-01

    Current state-of-the-art nanotechnology offers multiple benefits for radiation sensing applications. These include the ability to incorporate nano-sized radiation indicators into widely used materials such as paint, corrosion-resistant coatings, and ceramics to create nano-composite materials that can be widely used in everyday life. Additionally, nanotechnology may lead to the development of ultra-low power, flexible detection systems that can be embedded in clothing or other systems. Graphene, a single layer of graphite, exhibits exceptional electronic and structural properties, and is being investigated for high-frequency devices and sensors. Previous work indicates that graphene-oxide (GO) - a derivative of graphene - exhibits luminescent properties that can be tailored based on chemistry; however, exploration of graphene-oxide's ability to provide a sufficient change in luminescent properties when exposed to gamma or neutron radiation has not been carried out. We investigate the mechanisms of radiation-induced chemical modifications and radiation damage induced shifts in luminescence in graphene-oxide materials to provide a fundamental foundation for further development of radiation sensitive detection architectures. Additionally, we investigate the integration of hexagonal boron nitride (hBN) with graphene-based devices to evaluate radiation induced conductivity in nanoscale devices. Importantly, we demonstrate the sensitivity of graphene transport properties to the presence of alpha particles, and discuss the successful integration of hBN with large area graphene electrodes as a means to provide the foundation for large-area nanoscale radiation sensors.

  2. Curcumin Attenuates Gamma Radiation Induced Intestinal Damage in Rats

    International Nuclear Information System (INIS)

    EI-Tahawy, N.A.

    2009-01-01

    Small Intestine exhibits numerous morphological and functional alterations during radiation exposure. Oxidative stress, a factor implicated in the intestinal injury may contribute towards some of these alterations. The present work was designed to evaluate the efficacy of curcumin, a yellow pigment of turmeric on y-radiation-induced oxidative damage in the small intestine by measuring alterations in the level of thiobarbituric acid reactive substances (TSARS), serotonin metabolism, catecholamine levels, and monoamine oxidase (MAO) activity in parallel to changes in the architecture of intestinal tissues. In addition, monoamine level, MAO activity and TSARS level were determined in the serum. Curcumin was supplemented orally via gavages, to rats at a dose of (45 mg/ Kg body wt/ day) for 2 weeks pre-irradiation and the last supplementation was 30 min pre exposure to 6.5 Gy gamma radiations (applied as one shot dose). Animals were sacrificed on the 7th day after irradiation. The results demonstrated that, whole body exposure of rats to ionizing radiation has induced oxidative damage in small intestine obvious by significant increases of TSARS content, MAO activity and 5-hydroxy indole acetic acid (5-HIAA) and by significant decreases of serotonin (5-HT), dopamine (DA), norepinephrine (NE) and epinephrine (EPI) levels. In parallel histopathological studies of the small intestine of irradiated rats through light microscopic showed significant decrease in the number of villi, villus height, mixed sub mucosa layer with more fibres and fibroblasts. Intestinal damage was in parallel to significant alterations of serum MAO activity, TBARS, 5-HT, DA, NE and EPI levels. Administration of curcumin before irradiation has significantly improved the levels of monoamines in small intestine and serum of irradiated rats, which was associated with significant amelioration in MAO activity and TBARS contents

  3. Defense mechanisms against radiation induced teratogenic damage in mice

    International Nuclear Information System (INIS)

    Kato, F.; Ootsuyama, A.; Nomoto, S.; Norimura, T.

    2002-01-01

    Experimental studies with mice have established that fetuses at midgestational stage are highly susceptible to malformation at high, but not low, doses of radiation. When DNA damage is produced by a small amount of radiation, it is efficiently eliminated by DNA repair. However, DNA repair is not perfect. There must be defense mechanisms other than DNA repair. In order to elucidate the essential role of p53 gene in apoptotic tissue repair, we compared the incidence of radiation-induced malformations and deaths (deaths after day 10) in wild-type p53 (+/+) mice and null p53 (-/-) mice. For p53 (+/+) mice, an X-ray dose of 2 Gy given at a high dose-rate (450 mGy/min) to fetuses at 9.5 days of gestation was highly lethal and considerably teratogenic whereas it was only slightly lethal but highly teratogenic for p53 (-/-) fetuses. This reciprocal relationship of radiosensitivity to malformations and deaths supports the notion that fetal tissues have a p53 -dependent idguardianln of the tissue that aborts cells bearing radiation-induced teratogenic DNA damage. When an equal dose of 2 Gy given at a 400-fold lower dose-rate (1.2 mGy/min), this dose became not teratogenic for p53 (+/+) fetuses exhibiting p53 -dependent apoptosis, whereas this dose remained teratogenic for p53 (-/-) fetuses unable to carry out apoptosis. Furthermore, when the dose was divided into two equal dose fractions (1+1 Gy) at high dose rate, separated by 24 hours, the incidences of malformations were equal with control level for p53 (+/+), but higher for p53 (-/-) mice. Hence, complete elimination of teratogenic damage from irradiated tissues requires a concerted cooperation of two mechanisms; proficient DNA repair and p53-dependent apoptotic tissue repair

  4. Low doses of radiation: epidemiological investigations

    International Nuclear Information System (INIS)

    Dikiy, N.P.; Dovbnya, A.N.; Medvedeva, E.P.

    2013-01-01

    Influence of small dozes of radiation was investigated with the help epidemiologic evidence. Correlation analysis, regression analysis and frequency analysis were used for investigating morbidity of various cancer illnesses. The pollution of the environment and the fallout of radionuclides in 1962 and 1986 years have an influence upon morbidity of cancer. Influence of small dozes of radiation on health of the population is multifactorial. Therefore depending on other adverse external conditions the influence of radiation in small dozes can be increased or is weakened. Such character of influence of radiation in small dozes proposes the differentiated approach at realization of preventive measures. Especially it concerns regions with favorable ecological conditions.

  5. Severe fuel damage investigations of KFK/PNS

    International Nuclear Information System (INIS)

    Fiege, A.

    1983-01-01

    This report is a comprehensive review of the objectives, the program planning, the status and the further procedure of the investigations of KfK/PNS on severe core damage. The investigations were started in 1981 and will be finished in 1985/86. (orig.) [de

  6. The effect on radiation damage of structural material in a hybrid system by using a Monte Carlo radiation transport code

    International Nuclear Information System (INIS)

    Günay, Mehtap; Şarer, Başar; Kasap, Hızır

    2014-01-01

    Highlights: • The effects of some fluids on gas production rates in structural material were investigated. • The MCNPX-2.7.0 Monte Carlo code was used for three-dimensional calculations. • It was found that biggest contribution to gas production rates comes from Fe isotope of the. • The desirable values for 5% SFG-PuO 2 with respect to radiation damage were specified. - Abstract: In this study, the molten salt-heavy metal mixtures 99–95% Li20Sn80-1-5% SFG-Pu, 99–95% Li20Sn80-1-5% SFG-PuF4, 99-95% Li20Sn80-1-5% SFG-PuO2 were used as fluids. The fluids were used in the liquid first-wall, blanket and shield zones of the designed hybrid reactor system. 9Cr2WVTa ferritic steel with the width of 4 cm was used as the structural material. The parameters of radiation damage are proton, deuterium, tritium, He-3 and He-4 gas production rates. In this study, the effects of the selected fluid on the radiation damage, in terms of individual as well as total isotopes in the structural material, were investigated for 30 full power years (FPYs). Three-dimensional analyses were performed using the most recent version of the MCNPX-2.7.0 Monte Carlo radiation transport code and the ENDF/B-VII.0 nuclear data library

  7. Protective Effect of HSP25 on Radiation Induced Tissue Damage

    International Nuclear Information System (INIS)

    Lee, Hae-June; Lee, Yoon-Jin; Kwon, Hee-Choong; Bae, Sang-Woo; Lee, Yun-Sil; Kim, Sung Ho

    2007-01-01

    Control of cancer by irradiation therapy alone or in conjunction with combination chemotherapy is often limited by organ specific toxicity. Ionizing irradiation toxicity is initiated by damage to normal tissue near the tumor target and within the transit volume of radiotherapy beams. Irradiation-induced cellular, tissue, and organ damage is mediated by acute effects, which can be dose limiting. A latent period follows recovery from the acute reaction, then chronic irradiation fibrosis (late effects) pose a second cause of organ failure. HSP25/27 has been suggested to protect cells against apoptotic cell death triggered by hyperthermia, ionizing radiation, oxidative stress, Fas ligand, and cytotoxic drugs. And several mechanisms have been proposed to account for HSP27-mediated apoptotic protection. However radioprotective effect of HSP25/27 in vivo system has not yet been evaluated. The aim of this study was to evaluate the potential of exogenous HSP25 expression, as delivered by adenoviral vectors, to protect animal from radiation induced tissue damage

  8. Closure of laryngotracheal cavity and tracheostomy for intractable aspiration secondary to radiation encephalopathy or radiation damage of cranial nerve after radiotherapy of nasopharyngeal carcinoma.

    Science.gov (United States)

    Qu, Shenhong; Su, Zhengzhong; He, Xiaoguang; Li, Min; Li, Tianying

    2006-09-01

    Closure of the laryngotracheal cavity and tracheostomy is especially suitable for intractable aspiration secondary to radiation encephalopathy or damage of cranial nerve after radiation for nasopharyngeal carcinoma (NPC). To investigate the clinical value, technique, indications and contraindications of closure of the laryngotracheal cavity and tracheostomy for intractable aspiration secondary to radiation encephalopathy (REP) or radiation damage of cranial nerve after radiotherapy of NPC. Thirty patients, suffering from intractable aspiration secondary to radiotherapy for nasopharyngeal carcinoma, were treated with closure of the laryngotracheal cavity and tracheostomy and were observed for at least 1 year. Intractable aspiration and dyspnea were completely eradicated in all patients. The quality of their life was greatly improved.

  9. Protective Effects of Polysaccharides from Soybean Meal Against X-ray Radiation Induced Damage in Mouse Spleen Lymphocytes

    Directory of Open Access Journals (Sweden)

    Xin Yang

    2011-11-01

    Full Text Available The aim of this study was to investigate radioprotective effect of the polysaccharides from soybean meal (SMP against X-ray radiation-induced damage in mouse spleen lymphocytes. MTT and comet assay were performed to evaluate SMP’s ability to prevent cell death and DNA damage induced by radiation. The results show that, X-ray radiation (30 KV, 10 mA, 8 min (4 Gy can significantly increase cell death and DNA fragmentation of mouse spleen lymphocytes. Pretreatment with SMP for 2 h before radiation could increase cell viability, moreover, the SMP can reduce X-ray radiation-induced DNA damage. The percentage of tail DNA and the tail moment of the SMP groups were significantly lower than those of the radiation alone group (p < 0.05. These results suggest SMP may be a good candidate as a radioprotective agent.

  10. Modeling Radiation Damage to Pixel Sensors in the ATLAS Detector

    CERN Document Server

    Ducourthial, Audrey; The ATLAS collaboration

    2017-01-01

    Silicon pixel detectors are at the core of the current and planned upgrade of the ATLAS detector at the Large Hadron Collider (LHC). As the closest detector component to the interaction point, these detectors will be subjected to a significant amount of radiation over their lifetime: prior to the High-Luminosity LHC (HL-LHC), the innermost layers will receive a fluence in excess of $10^{15} n_{eq}/cm^2$ and the HL-HLC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. Simulating radiation damage is critical in order to make accurate predictions for current future detector performance that will enable searches for new particles and forces as well as precision measurements of Standard Model particles such as the Higgs boson. We present a digitization model that includes radiation damage effects to the ATLAS pixel sensors for the first time. In addition to thoroughly describing the setup, we present first predictions for basic pixel cluster properties alongside...

  11. Modeling Radiation Damage to Pixel Sensors in the ATLAS Detector

    CERN Document Server

    Rossini, Lorenzo; The ATLAS collaboration

    2018-01-01

    Silicon pixel detectors are at the core of the current and planned upgrade of the ATLAS detector at the Large Hadron Collider (LHC). As the closest detector component to the interaction point, these detectors will be subjected to a significant amount of radiation over their lifetime: prior to the High-Luminosity LHC (HL-LHC), the innermost layers will receive a fluence in excess of 10^15 neq/cm^2 and the HL-HLC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. Simulating radiation damage is critical in order to make accurate predictions for current and future detector performance that will enable searches for new particles and forces as well as precision measurements of Standard Model particles such as the Higgs boson. We present a digitization model that includes radiation damage effects to the ATLAS pixel sensors for the first time and considers both planar and 3D sensor designs. In addition to thoroughly describing the setup, we compare predictions for b...

  12. Modeling radiation damage to pixel sensors in the ATLAS detector

    CERN Document Server

    Ducourthial, Audrey; The ATLAS collaboration

    2017-01-01

    Silicon pixel detectors are at the core of the current and planned upgrade of the ATLAS detector at the Large Hadron Collider (LHC). As the closest detector component to the interaction point, these detectors will be subjected to a significant amount of radiation over their lifetime: prior to the High-Luminosity LHC (HL-LHC), the innermost layers will receive a fluence in excess of $10^{15}n_{eq}/cm^2$ and the HL-HLC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. Simulating radiation damage is critical in order to make accurate predictions for current future detector performance that will enable searches for new particles and forces as well as precision measurements of Standard Model particles such as the Higgs boson. We present a digitization model that includes radiation damage effects to the ATLAS pixel sensors for the first time. In addition to thoroughly describing the setup, we present first predictions for basic pixel cluster properties alongside ...

  13. Modeling radiation damage to pixel sensors in the ATLAS detector

    Science.gov (United States)

    Ducourthial, A.

    2018-03-01

    Silicon pixel detectors are at the core of the current and planned upgrade of the ATLAS detector at the Large Hadron Collider (LHC) . As the closest detector component to the interaction point, these detectors will be subject to a significant amount of radiation over their lifetime: prior to the High-Luminosity LHC (HL-LHC) [1], the innermost layers will receive a fluence in excess of 1015 neq/cm2 and the HL-LHC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. Simulating radiation damage is essential in order to make accurate predictions for current and future detector performance that will enable searches for new particles and forces as well as precision measurements of Standard Model particles such as the Higgs boson. We present a digitization model that includes radiation damage effects on the ATLAS pixel sensors for the first time. In addition to thoroughly describing the setup, we present first predictions for basic pixel cluster properties alongside early studies with LHC Run 2 proton-proton collision data.

  14. Modeling Radiation Damage to Pixel Sensors in the ATLAS Detector

    CERN Document Server

    Rossini, Lorenzo; The ATLAS collaboration

    2018-01-01

    Silicon pixel detectors are at the core of the current and planned upgrade of the ATLAS detector at the Large Hadron Collider (LHC). As the closest detector component to the interaction point, these detectors will be subjected to a significant amount of radiation over their lifetime: prior to the High- Luminosity LHC (HL-LHC), the innermost layers will receive a fluence in excess of 10^15 neq/cm2 and the HL-HLC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. Simulating radiation damage is critical in order to make accurate predictions for current future detector performance that will enable searches for new particles and forces as well as precision measurements of Standard Model particles such as the Higgs boson. We present a digitization model that includes radiation damage effects to the ATLAS pixel sensors for the first time and considers both planar and 3D sensor designs. In addition to thoroughly describing the setup, we compare predictions for basic...

  15. Pathological investigation of radiation necrosis

    International Nuclear Information System (INIS)

    Nakamura, Nishio; Yoshimura, Noriaki; Ikuta, Fusahiro

    1975-01-01

    The brain and spinal cord of an 18-year-old male, who suffered from cerebellar medulloblastoma with subarachnoid spread, had been irradiated by a large amount of Linac X-ray: 14,450 rads to the lower thoracic segments and 7,400 rads to the lumbar segments. The tumor at the roof of the 4th ventricle had disseminated along the ventricular system but was limited to the subarachnoid space of the cervical spinal cord. No remarkable changes were found in the volume or consistency of the thoracic and lumbar cord. Elasticity of the lower thoracic segment was greatly diminished and the cut surfaces were yellowish white and fragile. Microscopically extensive coagulation necrosis was observed with complete disintegration of myelin and axon. Vascular changes were most prominent in the smaller vessels, eg. hyalinous thickening, concentric cleavage, adventitial fibrosis and edema of small artery perivascular spaces, fibrin thrombi occulusion of arterioles and capillaries, and telangiectasia. In the lumbar spinal cord, moderate neuronal degeneration and protoplasmic astrocytosis were observed. Changes in the lumbar posterior white column were considered to be not only secondary degeneration but also a primary lesion caused by irradiation. Liquefactive necrosis in the gray matter of the cervical cord was thought to be a nonspecific circulatory disturbance because of the absence of vascular changes. Vascular changes were thought to be very important in the histological diagnosis of radiation myelopathy and it was supposed that increased permeability of the vessel walls was a factor in coagulation necrosis. They considered this case to have typical histology of radiation myelopathy. (Evans, J.)

  16. An approach to modelling radiation damage by fast ionizing particles

    International Nuclear Information System (INIS)

    Thomas, G.E.

    1987-01-01

    The paper presents a statistical approach to modelling radiation damage in small biological structures such as enzymes, viruses, and some cells. Irreparable damage is assumed to be caused by the occurrence of ionizations within sensitive regions. For structures containing double-stranded DNA, one or more ionizations occurring within each strand of the DNA will cause inactivation; for simpler structures without double-stranded DNA a single ionization within the structure will be sufficient for inactivation. Damaging ionizations occur along tracks of primary irradiating particles or along tracks of secondary particles released at primary ionizations. An inactivation probability is derived for each damage mechanism, expressed in integral form in terms of the radius of the biological structure (assumed spherical), rate of ionization along primary tracks, and maximum energy for secondary particles. The performance of each model is assessed by comparing results from the model with those derived from data from various experimental studies extracted from the literature. For structures where a single ionization is sufficient for inactivation, the model gives qualitatively promising results; for larger more complex structures containing double-stranded DNA, the model requires further refinements. (author)

  17. Importance of the neutron spectrum for determination of radiation damage

    International Nuclear Information System (INIS)

    Hehn, G.; Stiller, P.; Mattes, M.

    1977-01-01

    Since the radiation effects of neutrons depend strongly on the neutron energy, the correlation between the induced damage and the fluence of the fast neutrons shows appreciable disadvantages. The measured values of changes in material properties resulted in large differences for the same fast neutron fluence, being partly due to different neutron spectra. The uncertainties in damage data led to strong overdesign of important structural components. Different neutron environment at surveillance sample position may give an underestimation of the embrittlement in the reactor pressure vessel, which has to be avoided. The application of damage functions combined with accurately calculated neutron spectra, promise to be a reasonable solution. The damage function has the advantage of a phenomenological quantity that all spectral effects are included. But the correlation quantity has to be determined of high experimental costs. Therefore approximations of its energy distributions are very important. For the keV energy region the kerma function is reasonably good. For the MeV energy region a higher effort is needed to calculate the displacement cross section. The same holds for the low energy part. In all three parts the formation of stable material property levels may vary, so that the final correlation can be determined only by measurements of material properties in different neutron spectra. In material samples the spectra distribution of the displacement production rate was determined at different local positions outside the reactor core of a PWR and a fast breeder showing the most important energy regions of both reactors. (orig.) [de

  18. Repair of radiation damage caused by cyclotron-produced neutrons

    International Nuclear Information System (INIS)

    Martins, B.I.

    1979-01-01

    Hall et al. present experimental data on repair of sublethal damage in cultured mammalian cells exposed to 35 MeV neutrons and 60 Co γ rays. Hall and Kraljevic present experimental data on repair of potentially lethal damage in cultured mammalian cells exposed to 35 MeV neutrons and 210 kVp x rays. These results of Hall et al. are very difficult to explain from basic concepts in radiobiology. Contrary to Rossi, these data do not support his thesis that repair of radiation damage is dose-dependent and linear energy transfer independent. Nor do these results meet the expectations of multitarget-single hit theory which would require dose-independent repair equal to n. The observation of the same extrapolation number for neutrons and for x rays is also surprising. From the point of view of radiotherapy, the doses of interest are about 140 rad for neutrons and about 300 rad for x rays. There are no data for repair of potentially lethal damage below 800 rad for x rays and 400 rad for neutrons. The difference in survival between single and split dose is negligible up to a total of about 600 rad of x rays or of neutrons. These data of Hall et al. therefore have little significance to radiotherapists and are an enigma to radiobiologists

  19. Long-term radiation damage to a spaceborne germanium spectrometer

    CERN Document Server

    Kurczynski, P; Hull, E L; Palmer, D; Harris, M J; Seifert, H; Teegarden, B J; Gehrels, N; Cline, T L; Ramaty, R; Sheppard, D; Madden, N W; Luke, P N; Cork, C P; Landis, D A; Malone, D F; Hurley, K

    1999-01-01

    The Transient Gamma-Ray Spectrometer aboard the Wind spacecraft in deep space has observed gamma-ray bursts and solar events for four years. The germanium detector in the instrument has gradually deteriorated from exposure to the approx 10 sup 8 p/cm sup 2 /yr(>100 MeV) cosmic-ray flux. Low-energy tailing and loss of efficiency, attributed to hole trapping and conversion of the germanium from n- to p-type as a result of crystal damage, were observed. Raising the detector bias voltage ameliorated both difficulties and restored the spectrometer to working operation. Together, these observations extend our understanding of the effects of radiation damage to include the previously unsuccessfully studied regime of long-term operation in space. (author)

  20. Stem cell therapy for the treatment of radiation-induced normal tissue damage

    International Nuclear Information System (INIS)

    Chapel, A.; Benderitter, M.; Gourmelon, P.; Lataillade, J.J.; Gorin, N.C.

    2013-01-01

    Radiotherapy may induce irreversible damage on healthy tissues surrounding the tumour. In Europe, per year, 1.5 million patients undergo external radiotherapy. Acute adverse effect concern 80% of patients. The late adverse effect of radiotherapy concern 5 to 10% of them, which could be life threatening. Eradication of these manifestations is crucial. The French Institute of Radioprotection and Nuclear Safety (IRSN) contribute to understand effect of radiation on healthy tissue. IRSN is strongly implicated in the field of regeneration of healthy tissue after radiotherapy or radiological accident and in the clinical use of cell therapy in the treatment of irradiated patients. Our first success in cell therapy was the correction of deficient hematopoiesis in two patients. The intravenous injection of Mesenchymal Stem Cells (MSC) has restored bone marrow micro-environment after total body irradiation necessary to sustain hematopoiesis. Cutaneous radiation reactions play an important role in radiation accidents, but also as a limitation in radiotherapy and radio-oncology. We have evidenced for the first time, the efficiency of MSC therapy in the context of acute cutaneous and muscle damage following irradiation in five patients. Concerning the medical management of gastrointestinal disorder after irradiation, we have demonstrated the promising approach of the MSC treatment. We have shown that MSC migrate to damaged tissues and restore gut functions after radiation damage. The evaluation of stem cell therapy combining different sources of adult stem cells is under investigation

  1. The Juno Radiation Monitoring (RM) Investigation

    DEFF Research Database (Denmark)

    Becker, H. N.; Alexander, J. W.; Adriani, A.

    2017-01-01

    The Radiation Monitoring Investigation of the Juno Mission will actively retrieve and analyze the noise signatures from penetrating radiation in the images of Juno’s star cameras and science instruments at Jupiter. The investigation’s objective is to profile Jupiter’s > 10-MeV electron environmen...

  2. Modelling single shot damage thresholds of multilayer optics for high-intensity short-wavelength radiation sources

    NARCIS (Netherlands)

    Loch, R.A.; Sobierajski, R.; Louis, Eric; Bosgra, J.; Bosgra, J.; Bijkerk, Frederik

    2012-01-01

    The single shot damage thresholds of multilayer optics for highintensity short-wavelength radiation sources are theoretically investigated, using a model developed on the basis of experimental data obtained at the FLASH and LCLS free electron lasers. We compare the radiation hardness of commonly

  3. Compilation of radiation damage test data cable insulating materials

    CERN Document Server

    Schönbacher, H; CERN. Geneva

    1979-01-01

    This report summarizes radiation damage test data on commercially available organic cable insulation and jacket materials: ethylene- propylene rubber, Hypalon, neoprene rubber, polyethylene, polyurethane, polyvinylchloride, silicone rubber, etc. The materials have been irradiated in a nuclear reactor to integrated absorbed doses from 5*10/sup 5/ to 5*10/sup 6/ Gy. Mechanical properties, e.g. tensile strength, elongation at break, and hardness, have been tested on irradiated and non-irradiated samples. The results are presented in the form of tables and graphs, to show the effect of the absorbed dose on the measured properties. (13 refs).

  4. The cost of the radiation damage by the ALARA conception

    International Nuclear Information System (INIS)

    Kononovich, A.L.; Nosov, A.V.; Ivanov, A.V.; Pechkurov, A.V.

    2000-01-01

    A basis for the determination of the cost of the radiation risk as a method for its optimization are given. The correlation between different components of the risk is considered. The aim for optimization as a requirement on decrease of the cumulative risk is formulated. The reliability in the use of mathematic modelling on the determination of the cost of the risk and damage is noted. The lines of approach to determination of the cost of the risk based on the direct analysis of financial expenses are proposed. The results of estimation of the cost of the risk are given. The use of suggested approach is demonstrated on a hypothetical example [ru

  5. Radiation damage in an amorphous Lennard-Jones solid

    International Nuclear Information System (INIS)

    Chaki, T.K.; Li, J.C.M.

    1985-01-01

    A molecular-dynamics simulation of radiation damage in an amorphous Lennard-Jones solid has been undertaken. A three-dimensional structure of 685 atoms with periodic boundary conditions was used. An atom was injected inward from the middle of one surface, and as it lost its energy its velocity and position were recorded. The temperature profile around the injection direction was also calculated. The amorphous structure was examined before and after irradiation by calculating the volume distribution of the Voronoi polyhedra and its time evolution. The production of vacancies and interstitials was observed. The interstitials were found to disappear rapidly, and the vacancies slowly. (author)

  6. Radiation damage assessment by digital correlation of images

    International Nuclear Information System (INIS)

    Frank, J.; Salih, S.M.; Cosslett, V.E.

    1974-01-01

    Structural changes in the electron microscopic specimen due to radiation damage are conveniently studied by electron diffraction. However, two disadvantages of this method are that it does not work for amorphous specimens and that it is not sensitive to structural changes that affect only the phase of the structure factor. It has been proposed that a series of successive images taken under minimum exposure conditions could provide additional information in those cases where the relationship between object function and image intensity can be established. In order to test the proposed method, both lattice images and diffraction patterns of coronene crystals were recorded in separate experiments at controlled levels of exposure. (author)

  7. Molecular dynamics simulation of radiation damage cascades in diamond

    Energy Technology Data Exchange (ETDEWEB)

    Buchan, J. T. [Department of Physics and Astronomy, Curtin University, Perth, Western Australia 6845 (Australia); Robinson, M. [Nanochemistry Research Institute, Curtin University, Perth, Western Australia 6845 (Australia); Christie, H. J.; Roach, D. L.; Ross, D. K. [Physics and Materials Research Centre, School of Computing, Science and Engineering, University of Salford, Salford, Greater Manchester M5 4WT (United Kingdom); Marks, N. A. [Department of Physics and Astronomy, Curtin University, Perth, Western Australia 6845 (Australia); Nanochemistry Research Institute, Curtin University, Perth, Western Australia 6845 (Australia)

    2015-06-28

    Radiation damage cascades in diamond are studied by molecular dynamics simulations employing the Environment Dependent Interaction Potential for carbon. Primary knock-on atom (PKA) energies up to 2.5 keV are considered and a uniformly distributed set of 25 initial PKA directions provide robust statistics. The simulations reveal the atomistic origins of radiation-resistance in diamond and provide a comprehensive computational analysis of cascade evolution and dynamics. As for the case of graphite, the atomic trajectories are found to have a fractal-like character, thermal spikes are absent and only isolated point defects are generated. Quantitative analysis shows that the instantaneous maximum kinetic energy decays exponentially with time, and that the timescale of the ballistic phase has a power-law dependence on PKA energy. Defect recombination is efficient and independent of PKA energy, with only 50% of displacements resulting in defects, superior to graphite where the same quantity is nearly 75%.

  8. Modeling Radiation Damage to Pixel Sensors in the ATLAS Detector

    CERN Document Server

    Nachman, Benjamin Philip; The ATLAS collaboration

    2017-01-01

    Silicon Pixel detectors are at the core of the current and planned upgrade of the ATLAS detector. As the detector in closest proximity to the interaction point, these detectors will be subjected to a significant amount of radiation over their lifetime: prior to the HL-LHC, the innermost layers will receive a fluence in excess of $10^{15}$ 1 MeV $n_\\mathrm{eq}/\\mathrm{cm}^2$ and the HL-LHC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. This talk presents a digitization model that includes radiation damage effects to the ATLAS Pixel sensors for the first time. After a thorough description of the setup, predictions for basic Pixel cluster properties are presented alongside first validation studies with Run 2 collision data.

  9. Assessment of DNA damage and oxidative stress induced by radiation in Eisenia fetida

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Tae Ho; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Nili, Mohammad [Dawnesh Radiation Research Institute, Barcelona (Spain)

    2012-04-15

    Exposure of eukaryotic cells to ionizing radiation results in the immediate formation of free radicals and the occurrence of oxidative cell damage. Recently International Commission on Radiological Protection (ICRP) requires the effect data of ionizing radiation on non-human biota for the radiological protection of the environment. Based on their radioecological properties and their important role in the soil ecosystem, earthworms have been identified by the ICRP as one of the reference animals and plants (RAPs) to be used in environmental radiation protection. The investigation shows that oxidative stress is closely related to the exposed dose of radiation in the environment. To evaluate oxidative stress by ionizing radiation in the earthworm, we performed several experiments. The comet assay is known as a measurement which is one of the best techniques in assessing the DNA damage by oxidative stress. The SOD is a key enzyme in protecting cells against oxidative stress. An increase in the level of antioxidant enzyme such as SOD indicated that the exposure to radiation caused stress responses. Glutathione oxidation is considered as a maker for detection of reactive oxygen species (ROS). The GSSG levels increased progressively with increased exposure dose of ionizing radiation, which suggested a dose-dependent ROS generation.

  10. Protecting the radiation-damaged skin from friction: a mini review

    International Nuclear Information System (INIS)

    Herst, Patries M

    2014-01-01

    Radiation-induced skin reactions are an unavoidable side effect of external beam radiation therapy, particularly in areas prone to friction and excess moisture such as the axilla, head and neck region, perineum and skin folds. Clinical studies investigating interventions for preventing or managing these reactions have largely focussed on formulations with moisturising, anti-inflammatory, anti-microbial and wound healing properties. However, none of these interventions has emerged as a consistent candidate for best practice. Much less emphasis has been placed on evaluating ways to protect the radiation-damaged skin from friction and excess moisture. This mini review analyses the clinical evidence for barrier products that form a protective layer by adhering very closely to the skin folds and do not cause further trauma to the radiation-damaged skin upon removal. A database search identified only two types of barrier products that fitted these criteria and these were tested in two case series and six controlled clinical trials. Friction protection was most effective when the interventions were used from the start of treatment and continued for several weeks after completion of treatment. Soft silicone dressings (Mepilex Lite and Mepitel Film) and Cavilon No Sting Barrier Film, but not Cavilon Moisturizing Barrier Cream, decreased skin reaction severity, most likely due to differences in formulation and skin build-up properties. It seems that prophylactic use of friction protection of areas at risk could be a worthwhile addition to routine care of radiation-damaged skin

  11. A new cryostat for 'in situ' radiation damage studies

    International Nuclear Information System (INIS)

    Hariharan, Y.; Radhakrishnan, T.S.

    1977-01-01

    Conventional cryostats to study properties of materials between 4deg K and 300deg K base their designs either on continuous flow or bath type. A new cryostat which incorporates the advantages of both these has been designed and fabricated. This essentially has three chambers isolated from each other by poor thermal links. These are enclosed in a vacuum chamber and the whole assembly is immersed in a 4 He bath. The lowermost chamber is kept in good thermal contact with the bath. The second chamber can be maintained between 4deg K and 77deg K by circulation of cold 4 He vapour. The uppermost chamber can be maintained between 77deg K and 300deg K by circulating cold nitrogen vapours. There is a through axial hole in the centre, through which the sample can be moved up and down by means of a thin walled stainless steel tube. This comes out from the top of the cryostat through a Wilson seal. Thus the specimen can be anchored in any of the three chambers. This cryostat can be used to study the radiation damages caused by α-particles the sample being kept at 4.2deg K. There is provision for isolating the sample from the radiation zone. Isothermal and isochronal annealing of the damage caused can also be studied. Provision for taking out electrical leads from both inside and outside the sample chamber are also there. (auth.)

  12. Analytical studies into radiation-induced starch damage in black and white peppers

    International Nuclear Information System (INIS)

    Farkas, J.; Sharif, M.M.; Barabassy, S.

    1990-01-01

    In order to develop detection methods of radiation treatment, ground black pepper samples equilibrated to water activity levels of 0.25, 0.50 and 0.75 a w , respectively, were irradiated with gamma radiation doses of 0, 4, 8, 16 or 32 kGy, and their damaged starch content, reduced sugar content and alcohol induced turbidity of their aqueous extracts were investigated. The colorimetric method and the alcohol-induced turbidity showed statistically significant increase of starch damage at 4 kGy or higher dose levels. However, all investigated analytical indices of starch radio-depolymerization were changed less dramatically by irradiation than the apparent viscosity of the gelatinized suspensions of spices reported previously. (author) 15 refs.; 4 tabs

  13. Analysis of radiation damage in on-orbit solar array of Venus explorer Akatsuki

    International Nuclear Information System (INIS)

    Toyota, Hiroyuki; Shimada, Takanobu; Takahashi, You; Imamura, Takeshi; Hada, Yuko; Ishii, Takako T.; Isobe, Hiroaki; Asai, Ayumi; Shiota, Daikou

    2013-01-01

    This paper describes an analysis of radiation damage in solar array of Venus explorer Akatsuki observed on orbit. The output voltage of the solar array have shown sudden drops, which are most reasonably associated with radiation damage, three times since its launch. The analysis of these radiation damages is difficult, because no direct observation data of the spectra and the amount of the high-energy particles is available. We calculated the radiation damage using the relative damage coefficient (RDC) method assuming a typical spectral shape of protons. (author)

  14. 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

  15. Relation between four types of radiation damage and induced repair

    International Nuclear Information System (INIS)

    Radar, M.L.

    1977-08-01

    Four strains of Escherichia coli were exposed to uv and gamma radiation. Procedures are described for mutational studies, classification of revertants, inhibition of postirradiation DNA degradation and radioresistance. Comparisons were made of induction of the error-prone repair (epr) system with four mutagens; uv radiation, near uv radiation, gamma radiation, and DNA-protein crosslinks. An increase in the number of mutations was shown in every case. The observation that induction of mutagenesis, induction of inhibition of post-irradiation DNA degradation, and induction of radioresistance are closely parallel phenomena led to the investigation of the possibility that DNA-protein crosslinks which were known mutagens were also inducers of the epr system. The significance of the results is discussed

  16. An investigation of the damaged zone created by perforating

    International Nuclear Information System (INIS)

    Pucknell, J.K.; Behrmann, L.A.

    1991-01-01

    This paper reports on underbalance perforation flow experiments performed on reservoir and outcrop sandstones to investigate the perforation damaged zone. Cores from several different formations were perforated under reservoir conditions. After perforating, the cores were examined using CAT scans (Computer Aided tomography), thin sections and mercury porosimetry. In conjunction with these measurements, permeabilities in the damaged zone were measured using a minipermeameter and radial flow permeameter or were estimated from pore size distribution. The density and porosity of the damaged zone (at least for saturated rocks) is essentially the same as that in the undamaged rock. The damaged zone is not compacted, contrary to suggestions made in earlier work. However, the creation of this zone involves the destruction of large pores. The volume lost from these pores is replaced by microfractures created when rock grains are fractured by penetration of the shaped charge jet. This reduction in the average pore size causes a reduction in the permeability with the damaged zone. Although direct measurement of this permeability was made difficult by naturally occurring permeability variations, unambiguous measurements were obtained

  17. A Simplified Algorithm for Statistical Investigation of Damage Spreading

    International Nuclear Information System (INIS)

    Gecow, Andrzej

    2009-01-01

    On the way to simulating adaptive evolution of complex system describing a living object or human developed project, a fitness should be defined on node states or network external outputs. Feedbacks lead to circular attractors of these states or outputs which make it difficult to define a fitness. The main statistical effects of adaptive condition are the result of small change tendency and to appear, they only need a statistically correct size of damage initiated by evolutionary change of system. This observation allows to cut loops of feedbacks and in effect to obtain a particular statistically correct state instead of a long circular attractor which in the quenched model is expected for chaotic network with feedback. Defining fitness on such states is simple. We calculate only damaged nodes and only once. Such an algorithm is optimal for investigation of damage spreading i.e. statistical connections of structural parameters of initial change with the size of effected damage. It is a reversed-annealed method--function and states (signals) may be randomly substituted but connections are important and are preserved. The small damages important for adaptive evolution are correctly depicted in comparison to Derrida annealed approximation which expects equilibrium levels for large networks. The algorithm indicates these levels correctly. The relevant program in Pascal, which executes the algorithm for a wide range of parameters, can be obtained from the author.

  18. Action of the chlorophyllin on the genetic damage induced by gamma radiation in germinal cells of Drosophila Melanogaster

    International Nuclear Information System (INIS)

    Cruces, M.P.; Pimentel, A.E.; Moreno, A.; Moreno, R.

    2003-01-01

    The obtained results using somatic cells, they have evidenced that the chlorophyllin (CHLN) it can act inhibiting or increasing the damage caused by different mutagens. The objective of this investigation is to evaluate the effect of the CHLN on the damage induced by gamma radiation in germinal cells of Drosophila. Two tests were used, the lost of the X chromosome and the conventional test of lethal recessive bound to the sex (LRLS); both with a system of litters. The obtained results in both essays, indicated that the CHLN doesn't reduce the damage induced by the gamma radiation in none of the cellular monitored states. (Author)

  19. Study of the effect of dose-rate on radiation-induced damage to human erythrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Krokosz, Anita [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland)]. E-mail: krokosz@biol.uni.lodz.pl; Koziczak, Renata [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland); Gonciarz, Marta [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland); Szweda-Lewandowska, Zofia [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland)

    2006-01-15

    Human erythrocytes suspended in an isotonic Na-phosphate buffer, pH 7.4 (hematocrit of 2%) were irradiated with {gamma}-rays at three dose-rates of 66.7, 36.7, 25 Gy min{sup -1} in order to investigate the influence of the dose-rate on radiation-induced membrane damage, hemoglobin oxidation and loss of reduced glutathione. The obtained results showed that such processes as erythrocyte hemolysis, lipid and protein destruction depend on the radiation dose-rate. The parameter values describing these processes showed an inverse dose-rate effect.

  20. Study of the effect of dose-rate on radiation-induced damage to human erythrocytes

    International Nuclear Information System (INIS)

    Krokosz, Anita; Koziczak, Renata; Gonciarz, Marta; Szweda-Lewandowska, Zofia

    2006-01-01

    Human erythrocytes suspended in an isotonic Na-phosphate buffer, pH 7.4 (hematocrit of 2%) were irradiated with γ-rays at three dose-rates of 66.7, 36.7, 25 Gy min -1 in order to investigate the influence of the dose-rate on radiation-induced membrane damage, hemoglobin oxidation and loss of reduced glutathione. The obtained results showed that such processes as erythrocyte hemolysis, lipid and protein destruction depend on the radiation dose-rate. The parameter values describing these processes showed an inverse dose-rate effect

  1. Synchrotron radiation. 4. Analyses of biological samples using synchrotron radiation. 3. Research on radiation damage to DNA using synchrotron radiation

    International Nuclear Information System (INIS)

    Takakura, Kaoru

    1998-01-01

    This review described how the synchrotron radiation (SR) is used to solve problems unknown hitherto in radiation biology. Historically, the target substance of UV light in bacterial death was suggested to be nucleic acid in 1930. Researches on the radiation damage to DNA were begun at around 1960 and have mainly used UV light, X-ray and γray. Soft X-ray and vacuum UV whose energy covering from several eV to scores of keV have not been used since UV and X-ray lack the energy of this range. This is one of reasons why detailed process leading to radiation-induced death, carcinogenicity and mutation has not been known hitherto. RS possesses wide range of energy, i.e., from UV to hard X-ray, of high intensity, which is helpful for studying the unknown problems. The RS studies were begun in nineteen-seventies. Those include the action spectrum studies and atomic target studies. In the former, the course of the effect, e.g., the mechanism of DNA double strand breakage, can be elucidated. In the latter, photon of known energy can be irradiated to the specified atom like phosphorus in DNA which elucidating the precise physicochemical process of the breakage. Use of RS in these studies is thought still meaningful in future. (K.H.) 62 refs

  2. Radiation damages in chemical components of organic scintillator detectors

    International Nuclear Information System (INIS)

    Fernandes Neto, Jose Maria

    2003-01-01

    Samples containing PPO (1%, g/ml), diluted in toluene, they were irradiated in a 60 Co irradiator (6.46 kGy/h) at different doses. The PPO concentration decay bi-exponentially with the dose, generating the degradation products: benzoic acid, benzamide and benzilic alcohol. The liquid scintillator system was not sensitive to the radiation damage until 20 kGy. Otherwise, the pulse height analysis showed that dose among 30 to 40 kGy generate significant loss of quality of the sensor (liquid scintillating) and the light yield was reduced in half with the dose of (34.04 ± 0.80) kGy. This value practically was confirmed by the photo peak position analysis that resulted D 1/2 = (31.7 ± 1,4) kGy, The transmittance, at 360 nm, of the irradiated solution decreased exponentially. The compartmental model using five compartments (fast decay PPO, slow decay PPO, benzamide, benzoic acid and benzilic alcohol) it was satisfactory to explain the decay of the PPO in its degradation products in function of the dose. The explanation coefficient r 2 = 0.985636 assures that the model was capable to explain 98.6% of the experimental variations. The Target Theory together with the Compartmental Analysis showed that PPO irradiated in toluene solution presents two sensitive molecular diameters both of them larger than the true PPO diameter. >From this analysis it showed that the radiolytic are generated, comparatively, at four toluene molecules diameter far from PPO molecules. For each one PPO-target it was calculated the G parameter (damage/100 eV). For the target expressed by the fast decay the G value was (418.4 ± 54.1) damages/100 eV, and for the slow decay target the G value was (54.5 ± 8.9) damages/100 eV. The energies involved in the chemical reactions were w (0.239 ± 0.031) eV/damage (fast decay) and w = (1 834 ± 0.301) eV/damage (slow decay). (author)

  3. Mitigating radiation damage of single photon detectors for space applications

    Energy Technology Data Exchange (ETDEWEB)

    Anisimova, Elena; Higgins, Brendon L.; Bourgoin, Jean-Philippe [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Cranmer, Miles [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); Choi, Eric [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); Magellan Aerospace, Ottawa, ON (Canada); Hudson, Danya; Piche, Louis P.; Scott, Alan [Honeywell Aerospace (formerly COM DEV Ltd.), Ottawa, ON (Canada); Makarov, Vadim [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); Jennewein, Thomas [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Canadian Institute for Advanced Research, Quantum Information Science Program, Toronto, ON (Canada)

    2017-12-15

    Single-photon detectors in space must retain useful performance characteristics despite being bombarded with sub-atomic particles. Mitigating the effects of this space radiation is vital to enabling new space applications which require high-fidelity single-photon detection. To this end, we conducted proton radiation tests of various models of avalanche photodiodes (APDs) and one model of photomultiplier tube potentially suitable for satellite-based quantum communications. The samples were irradiated with 106 MeV protons at doses approximately equivalent to lifetimes of 0.6, 6, 12 and 24 months in a low-Earth polar orbit. Although most detection properties were preserved, including efficiency, timing jitter and afterpulsing probability, all APD samples demonstrated significant increases in dark count rate (DCR) due to radiation-induced damage, many orders of magnitude higher than the 200 counts per second (cps) required for ground-to-satellite quantum communications. We then successfully demonstrated the mitigation of this DCR degradation through the use of deep cooling, to as low as -86 C. This achieved DCR below the required 200 cps over the 24 months orbit duration. DCR was further reduced by thermal annealing at temperatures of +50 to +100 C. (orig.)

  4. Grape Seed Oil Extract Protects Against Radiation-Induced Oxidative Damage in Rats Eyes

    International Nuclear Information System (INIS)

    Naguib, N.I.

    2011-01-01

    The present study was carried out to investigate the beneficial effects of grape seed oil on radiation-induced oxidative stress in the irradiated rat eyes. The rats were divided into three groups; control group that received distilled water, irradiated group (R) that exposed to gamma radiation as a single dose of 6.4 Gy and irradiated + grape seed oil group (R+GSO) that administered grape seed oil for seven consecutive days then exposed to the same single gamma radiation dose followed by grape seed oil for seven additional days. Histopathological results revealed protective effect of grape seed oil on the eye tissues of rat. The results lead to the conclusion that administration of GSO prior to radiation exposure may be a promising attempt in attenuating the extent of oxidative damage accompanying radiotherapy

  5. Investigation of cutting-induced damage in CMC bend bars

    Directory of Open Access Journals (Sweden)

    Neubrand A.

    2015-01-01

    Full Text Available Ceramic matrix composites (“CMC” with a strong fibre-matrix interface can be made damage-tolerant by introducing a highly porous matrix. Such composites typically have only a low interlaminar shear strength, which can potentially promote damage when preparing specimens or components by cutting. In order to investigate the damage induced by different cutting methods, waterjet cutting with and without abrasives, laser-cutting, wire eroding and cutoff grinding were used to cut plates of two different CMCs with a matrix porosity up to 35 vol.-%. For each combination of cutting method and composite, the flexural and interlaminar shear strength of the resulting specimens was determined. Additionally, the integrity of the regions near the cut surfaces was investigated by high-resolution x-ray computer tomography. It could be shown that the geometrical quality of the cut is strongly affected by the cutting method employed. Laser cut and waterjet cut specimens showed damage and delaminations near the cut surface leading to a reduced interlaminar shear strength of short bend bars in extreme cases.

  6. High and Low LET Radiation Differentially Induce Normal Tissue Damage Signals

    International Nuclear Information System (INIS)

    Niemantsverdriet, Maarten; Goethem, Marc-Jan van; Bron, Reinier; Hogewerf, Wytse; Brandenburg, Sytze; Langendijk, Johannes A.; Luijk, Peter van; Coppes, Robert P.

    2012-01-01

    Purpose: Radiotherapy using high linear energy transfer (LET) radiation is aimed at efficiently killing tumor cells while minimizing dose (biological effective) to normal tissues to prevent toxicity. It is well established that high LET radiation results in lower cell survival per absorbed dose than low LET radiation. However, whether various mechanisms involved in the development of normal tissue damage may be regulated differentially is not known. Therefore the aim of this study was to investigate whether two actions related to normal tissue toxicity, p53-induced apoptosis and expression of the profibrotic gene PAI-1 (plasminogen activator inhibitor 1), are differentially induced by high and low LET radiation. Methods and Materials: Cells were irradiated with high LET carbon ions or low LET photons. Cell survival assays were performed, profibrotic PAI-1 expression was monitored by quantitative polymerase chain reaction, and apoptosis was assayed by annexin V staining. Activation of p53 by phosphorylation at serine 315 and serine 37 was monitored by Western blotting. Transfections of plasmids expressing p53 mutated at serines 315 and 37 were used to test the requirement of these residues for apoptosis and expression of PAI-1. Results: As expected, cell survival was lower and induction of apoptosis was higher in high -LET irradiated cells. Interestingly, induction of the profibrotic PAI-1 gene was similar with high and low LET radiation. In agreement with this finding, phosphorylation of p53 at serine 315 involved in PAI-1 expression was similar with high and low LET radiation, whereas phosphorylation of p53 at serine 37, involved in apoptosis induction, was much higher after high LET irradiation. Conclusions: Our results indicate that diverse mechanisms involved in the development of normal tissue damage may be differentially affected by high and low LET radiation. This may have consequences for the development and manifestation of normal tissue damage.

  7. Nuclear radiation applications in hydrological investigations

    International Nuclear Information System (INIS)

    Rao, S.M.

    1978-01-01

    The applications of radiation sources for the determination of water and soil properties in hydrological investigations are many and varied. These include snow gauging, soil moisture and density determinations, measurement of suspended sediment concentrations in natural streams and nuclear well logging for groundwater exploitation. Besides the above, many radiation physics aspects play an important role in the development of radiotracer techniques, particularly in sediment transport studies. The article reviews the above applications with reference to their limitations and advantages. (author)

  8. Radiation damage studies on natural rock salt from various geological localities of interest to the radioactive waste disposal program

    International Nuclear Information System (INIS)

    Levy, P.W.

    1981-01-01

    As part of a program to investigate radiation damage in geological materials of interest to the radioactive waste disposal program, radiation damage, particularly radiation induced sodium metal colloid formation, has been studied in 14 natural rock salt samples. All measurements were made with equipment for making optical absorption and other measurements on samples, in a temperature controlled irradiation chamber, during and after 0.5 to 3.0 MeV electron irradiation. Samples were chosen for practical and scientific purposes, from localities that are potential repository sites and from different horizons at certain localities

  9. Imperfection and radiation damage in protein crystals studied with coherent radiation

    International Nuclear Information System (INIS)

    Nave, Colin; Sutton, Geoff; Evans, Gwyndaf; Owen, Robin; Rau, Christoph; Robinson, Ian; Stuart, David Ian

    2016-01-01

    Coherent diffraction observations from polyhedra crystals at cryotemperature are reported. Information is obtained about the lattice strain and the changes with radiation damage. Fringes and speckles occur within diffraction spots when a crystal is illuminated with coherent radiation during X-ray diffraction. The additional information in these features provides insight into the imperfections in the crystal at the sub-micrometre scale. In addition, these features can provide more accurate intensity measurements (e.g. by model-based profile fitting), detwinning (by distinguishing the various components), phasing (by exploiting sampling of the molecular transform) and refinement (by distinguishing regions with different unit-cell parameters). In order to exploit these potential benefits, the features due to coherent diffraction have to be recorded and any change due to radiation damage properly modelled. Initial results from recording coherent diffraction at cryotemperatures from polyhedrin crystals of approximately 2 µm in size are described. These measurements allowed information about the type of crystal imperfections to be obtained at the sub-micrometre level, together with the changes due to radiation damage

  10. Imperfection and radiation damage in protein crystals studied with coherent radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nave, Colin, E-mail: colin.nave@diamond.ac.uk [Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom); Sutton, Geoff [Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Evans, Gwyndaf; Owen, Robin; Rau, Christoph [Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom); Robinson, Ian [University College London, 17–19 Gordon Street, London WC1H 0AH (United Kingdom); Stuart, David Ian [Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom)

    2016-01-01

    Coherent diffraction observations from polyhedra crystals at cryotemperature are reported. Information is obtained about the lattice strain and the changes with radiation damage. Fringes and speckles occur within diffraction spots when a crystal is illuminated with coherent radiation during X-ray diffraction. The additional information in these features provides insight into the imperfections in the crystal at the sub-micrometre scale. In addition, these features can provide more accurate intensity measurements (e.g. by model-based profile fitting), detwinning (by distinguishing the various components), phasing (by exploiting sampling of the molecular transform) and refinement (by distinguishing regions with different unit-cell parameters). In order to exploit these potential benefits, the features due to coherent diffraction have to be recorded and any change due to radiation damage properly modelled. Initial results from recording coherent diffraction at cryotemperatures from polyhedrin crystals of approximately 2 µm in size are described. These measurements allowed information about the type of crystal imperfections to be obtained at the sub-micrometre level, together with the changes due to radiation damage.

  11. Protection of DPPC phospholipid liposomal membrane against radiation oxidative damage by antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Marathe, D.L.; Pandey, B.N.; Mishra, K.P [Bhabha Atomic Research Centre, Mumbai (India)

    2000-05-01

    Investigations in our laboratory on egg lecithin liposomes have recently showed a marked protection against damage by gamma radiation when cholesterol was present in the composition of vesicles suggesting a role of bilayer molecular architecture in the mechanism of free radical mediated lipid peroxidation. Present study was designed to determine the changes in bilayer permeability in DPPC unilamelar vesicles after exposure to gamma radiation by monitoring the leakage of pre-loaded carboxyfluorescein (CF), a marker loaded in aqueous interior of vesicle and fluidity alterations in the bilayer using fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH), a membrane bilayer probe. It was found that radiation doses of an order of magnitude higher were required to produce detectable changes in vesicles of DPPC than in the vesicles of egg lecithin suggesting a modulating role of chemical nature of composition in the membrane radiation sensitivity. It was significant to find that the leakage of CF from and incorporation of DPH into vesicle bilayer showed similar response pattern to radiation doses (0.1-6 kGy) which was also found to be dose rate dependent. Presence of antioxidants; alpha-tocopherol (0.15 mole %) in the bilayer membrane or ascorbic acid (0.1 mM) in the aqueous region significantly protected DPPC vesicles from radiation damage as determined from DPH uptake kinetics suggesting involvement of reactive free radicals of lipids as well as water radicals in the mechanism of membrane peroxidative damage. The magnitude of protection was found to increase with the increasing concentration of both these antioxidants but comparisons showed that {alpha}-tocopherol was far more effective in protecting the vesicles than ascorbic acid. These results contribute to our understanding of the mechanism of radiation oxidative damage and its modification by radical scavenging and/or organizational modulation which emphasize the importance of structure and composition of

  12. Protection of DPPC phospholipid liposomal membrane against radiation oxidative damage by antioxidants

    International Nuclear Information System (INIS)

    Marathe, D.L.; Pandey, B.N.; Mishra, K.P

    2000-01-01

    Investigations in our laboratory on egg lecithin liposomes have recently showed a marked protection against damage by gamma radiation when cholesterol was present in the composition of vesicles suggesting a role of bilayer molecular architecture in the mechanism of free radical mediated lipid peroxidation. Present study was designed to determine the changes in bilayer permeability in DPPC unilamelar vesicles after exposure to gamma radiation by monitoring the leakage of pre-loaded carboxyfluorescein (CF), a marker loaded in aqueous interior of vesicle and fluidity alterations in the bilayer using fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH), a membrane bilayer probe. It was found that radiation doses of an order of magnitude higher were required to produce detectable changes in vesicles of DPPC than in the vesicles of egg lecithin suggesting a modulating role of chemical nature of composition in the membrane radiation sensitivity. It was significant to find that the leakage of CF from and incorporation of DPH into vesicle bilayer showed similar response pattern to radiation doses (0.1-6 kGy) which was also found to be dose rate dependent. Presence of antioxidants; alpha-tocopherol (0.15 mole %) in the bilayer membrane or ascorbic acid (0.1 mM) in the aqueous region significantly protected DPPC vesicles from radiation damage as determined from DPH uptake kinetics suggesting involvement of reactive free radicals of lipids as well as water radicals in the mechanism of membrane peroxidative damage. The magnitude of protection was found to increase with the increasing concentration of both these antioxidants but comparisons showed that α-tocopherol was far more effective in protecting the vesicles than ascorbic acid. These results contribute to our understanding of the mechanism of radiation oxidative damage and its modification by radical scavenging and/or organizational modulation which emphasize the importance of structure and composition of

  13. Effects of ionizing radiation on laser-induced damage in SiO/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Soileau, M J; Mansour, N; Canto, E; Griscom, D L

    1988-05-01

    The effects of radiation damage on bulk laser-induced damage in SiO/sub 2/ were investigated. Samples studied included Spectrasil A, B, and WF (water free). Measurements of laser-induced breakdown were conducted with 532 and 1064 nm laser pulses of approximately 20 ns duration. Reductions of up to 40% in the laser-induced breakdown threshold were observed at 532 nm for samples exposed to 10/sup 8/ rad of ..gamma..-radiation. The decrease in breakdown threshold for irradiated SiO/sub 2/ samples at 532 nm was found to be proportional to the linear absorption of the specimen at 266 nm. These results are in good agreement with a proposed model which suggests that two-photon absorption initiated avalanche process is responsible for laser-induced breakdown for these materials.

  14. Silicon P.I.N. Junctions used for studies of radiation damage

    International Nuclear Information System (INIS)

    Lanore, J.

    1964-06-01

    Irradiation of silicon P.I.N. junction has been studied primarily for the purpose of developing a radiation damage dosimeter, but also for the purpose of investigating silicon itself. It is known that the rate of recombination of electrons and holes is a linear function of defects introduced by neutron irradiation. Two methods have been used to measure that rate of recombination: forward characteristic measurements, recovery time measurements. In order to explain how these two parameters depend on recombination rate we have given a theory of the P.I.N. junction. We have also given an idea of the carrier lifetime dependence versus temperature. Annealing effects in the range of 70 to 700 K have also been studied, we found five annealing stages with corresponding activation energies. As an application for these studies, we developed a radiation damage dosimeter with which we made several experiments in facilities such as Naiade or Marias. (author) [fr

  15. Collision density approach of radiation damage in a multispecies medium

    International Nuclear Information System (INIS)

    Lux, I.; Pazsit, I.

    1981-01-01

    Space-energy dependent forward type equations for the collision densities of energetic atoms in a multispecies semi-infinite homogeneous medium are formulated. Introduction of the one-dimensional isotropic forward-backward model of Fermi for the scattering and application of the Laplace transform with respect to the lethargy variable will lead to a linear differential equation system with constant coefficients. This equation system is solved for an arbitrary number of species and relations between the collision densities and defect distributions of the different species are given in the Kinchin-Pease model of radiation damage. The case of an alien particle incident on a two-component target is examined in some detail and the sputtering spectra for the three species are given numerically. (author)

  16. Radiation damage in amorphous solids - a computer simulation

    International Nuclear Information System (INIS)

    Chaki, T.K.; Li, J.C.M.

    1984-01-01

    It is known for crystalline materials that injection of high energy atoms introduces point defects. The nature of defects is not known for amorphous solids. So a molecular dynamic simulation of radiation damage in an amorphous metal was carried out. An amorphous structure of 685 atoms with periodic boundary conditions in all 3 dimensions was equilibrated first. Then one atom on the surface was given a high initial velocity so it was injected inward. Radial temperature distribution around the line of injection was calculated as a function of time. Void distribution and its evolution with time in the direction of injection was calculated by counting the atomic centers in thin slabs perpendicular to the line of injection. The swelling of the whole solid was calculated also. Some results are compared with experiments

  17. Radiation diagnosis of pelvic ring damages in acute injury

    International Nuclear Information System (INIS)

    Dytalov, M.M.

    2000-01-01

    Data on 58 victims with multifocal damages to the pelvic ring were used to examine the diagnostic potentialities of different radiation diagnostic techniques and to compare their resolving power. The later was 65.1, 83.3 and 94.7% in plain and multidimensional X-ray studies, and computed tomography, respectively. Complex of signs is described closed sacral fractures on the plain and oblique pelvic inlet (caudal) radiograms proposed, which could improve the diagnosis of fractures by 8.8 times, and an original orthopedic gauze-plate for the detection and estimation of invisible pelvic bone displacement, and an original procedure for pelvic X-ray study with target load in acute injury. This all can improve the quality of examination of casualties substantially and define indications for different treatments more precise [ru

  18. Sensitization of ultraviolet radiation damage in bacteria and mammalian cells

    International Nuclear Information System (INIS)

    Fisher, G.J.; Watts, M.E.; Patel, K.B.; Adams, G.E.

    1978-01-01

    Bacteria (Serratia marcescens) and mammalian cells (Chinese hamsters V79-379A) were irradiated in monolayers with ultraviolet light at 254 nm or 365 nm in the presence or absence of radiosensitizing drugs. At 254 nm, killing is very efficient (Dsub(37) approximately equal 1 J m -2 exposure, or approximately equal 6 x 10 4 photons absorbed by DNA per bacterium), and sensitizers have no effect. At 365 nm, cells are not killed in buffer, but are inactivated in the presence of nifurpipone or misonidazole. Lethal exposures (approximately equal 5 x 10 3 J m -2 at 10 nM misonidazole) correspond to about 10 7 photons absorbed by sensitizer molecules per bacterium. Toxicity of stable photoproducts of the drugs is not involved, nor is oxygen required. Hence the transient species formed by photo-excitation of radiosensitizer molecules are capable of killing cells in the absence of other types of radiation damage. (author)

  19. Collision density approach of radiation damage in a multispecies medium

    Energy Technology Data Exchange (ETDEWEB)

    Lux, I; Pazsit, I [Koezponti Elelmiszeripari Kutato Intezet, Budapest (Hungary)

    1981-01-01

    Space-energy dependent forward type equations for the collision densities of energetic atoms in a multispecies semi-infinite homogeneous medium are formulated. Introduction of the one-dimensional isotropic forward-backward model of Fermi for the scattering and application of the Laplace transform with respect to the lethargy variable will lead to a linear differential equation system with constant coefficients. This equation system is solved for an arbitrary number of species and relations between the collision densities and defect distributions of the different species are given in the Kinchin-Pease model of radiation damage. The case of an alien particle incident on a two-component target is examined in some detail and the sputtering spectra for the three species are given numerically.

  20. Biological rhythms for rehabilitation of radiation damage of population

    International Nuclear Information System (INIS)

    Goncharova, T.G.; Vasil'eva, G.S.; Efimov, M.L.

    1999-01-01

    Considerable disturbances in biological eurhythmycal structure of redoracu were discovered for people living in Borodulikha area of the Semipalatinsk test site. The deep desynchronise may result in a development of the cardiovascular, bronco-pulmonary, endocrine, oncologic, neuro psychic diseases. A method to correct the biological eurhythmycal structure was developed. Homeopathic doses of melatonin ('rhythm driver' managing the most regenerating and immune systems) and uthynol (promoting production of dehydroepiandrosterone of maternal prehormone of 27 hormones) were used to provide the general correction. The endocrine diseases are not practically subjected to the homeopathic correction. The sub correction was sometimes carried out after 5 months. The developed methods of rehabilitation of the radiation damages are unique, since they allow performing the homeopathic correction using the acupuncture monitoring

  1. Measurement of radiation damage on an epoxy-based optical glue

    International Nuclear Information System (INIS)

    Huang, H.C.; Peng, K.C.; Sahu, S.K.; Ueno, K.; Chang, Y.H.; Wang, C.H.; Hou, W.S.

    1997-01-01

    We measured the radiation damage on an optical glue called Eccobond-24, which is a candidate for CsI and BGO crystal calorimeters of the BELLE detector of the KEK B-factory. Absorption spectrophotometry in the range 300-800 nm was used to monitor the radiation damage. The maximum equivalent dose was 1.64 Mrad. The glue shows effects of damage, but is acceptable for the radiation level in the above-mentioned experiment. (orig.)

  2. Ultraviolet radiation-mediated damage to cellular DNA

    International Nuclear Information System (INIS)

    Cadet, Jean; Sage, Evelyne; Douki, Thierry

    2005-01-01

    Emphasis is placed in this review article on recent aspects of the photochemistry of cellular DNA in which both the UVB and UVA components of solar radiation are implicated individually or synergistically. Interestingly, further mechanistic insights into the UV-induced formation of DNA photoproducts were gained from the application of new accurate and sensitive chromatographic and enzymic assays aimed at measuring base damage. Thus, each of the twelve possible dimeric photoproducts that are produced at the four main bipyrimidine sites can now be singled out as dinucleoside monophosphates that are enzymatically released from UV-irradiated DNA. This was achieved using a recently developed high-performance liquid chromatography-tandem mass spectrometry assay (HPLC-MS/MS) assay after DNA extraction and appropriate enzymic digestion. Interestingly, a similar photoproduct distribution pattern is observed in both isolated and cellular DNA upon exposure to low doses of either UVC or UVB radiation. This applies more specifically to the DNA of rodent and human cells, the cis-syn cyclobutadithymine being predominant over the two other main photolesions, namely thymine-cytosine pyrimidine (6-4) pyrimidone adduct and the related cyclobutyl dimer. UVA-irradiation was found to generate cyclobutane dimers at TT and to a lower extent at TC sites as a likely result of energy transfer mechanism involving still unknown photoexcited chromophore(s). Oxidative damage to DNA is also induced although less efficiently by UVA-mediated photosensitization processes that mostly involved 1 O 2 together with a smaller contribution of hydroxyl radical-mediated reactions through initially generated superoxide radicals

  3. Micronuclei: sensitivity for the detection of radiation induced damage

    International Nuclear Information System (INIS)

    Di Giorgio, M.; Nasazzi, N.B.; Taja, M.R.

    1998-01-01

    The in vitro cytokinesis-block (CB) micronucleus (MN) assay for human peripheral blood has been used extensively for the assessment of chromosomal damage induced by ionizing radiation and chemicals and considered a suitable biological dosimeter for estimating in vivo whole body exposures, particularly in the case of large scale radiation accidents. One of the major drawbacks of the MN assay is its reduced sensitivity for the detection of damage induced by low doses of low LET radiation, due to the high variability among the spontaneous MN frequencies. It is suggested that age, smoking habit and sex are the main confounding factors that contribute to the observed variability. Previous work in our laboratory, shows a significant positive correlation of the spontaneous and radiation induced MN frequencies with age and smoking habit, the latter being the strongest confounder. These findings led to in vitro studies of the dose-response relationships for smoking and non smoking donors evaluated separately, using 60 Co γ rays. The objectives of the present work are: 1-To increase the amount of data of the dose-response relationships, using γ rays from a 60 Co source, for smoking and non smoking donors, in order to find, if applicable, a correction factor for the calibration curve that takes into account the smoking habit of the individual in the case of accidental overexposure dose assessment, particularly in the low dose range. 2-To establish general conclusions on the current state of the technique. The sample for smoking and non smoking calibration curves was enlarged in the range of 0Gy to 2Gy. The fitting of both curves, performed up to the 2Gy dose, resulted in a linear quadratic model. MN distribution among bi nucleated cells was found to be over dispersed with respect to Poisson distribution, the average ratio of variance to mean being 1.13 for non smokers and 1.17 for smokers. Each fitted calibration curve, for smoking and non smoking donors, fell within the 95

  4. Dislocations and radiation damage in α-uranium

    International Nuclear Information System (INIS)

    Leteurtre, J.

    1969-01-01

    Dislocations in α-uranium were studied by electron microscopy. Electropolishing of thin foils was performed at low temperature (-110 deg. C) to prevent oxidation. Burgers vectors of twins dislocations are defined. Interactions between slip and twinning are studied from both experimental and theoretical point of view. Samples irradiated at several burn-up were examined. In order to explain our micrographic results, and also all information gathered in literature about radiation damage in α-uranium, a coherent model is propound for the fission particles effects. We analyse the influences of parameters: temperature, dislocation density, impurity content. The number of point defects created by one initial fission is determined for pure and annealed metal. The importance of the self-anneal which occurs immediately in each displacement spike, and the anneal due to a new fission on the damage resulting from a previous fission, are estimated. The focussing distance in [100] direction is found to be about 1000 Angstrom, at 4 deg. K. (author) [fr

  5. Long term radiological features of radiation-induced lung damage.

    Science.gov (United States)

    Veiga, Catarina; Landau, David; McClelland, Jamie R; Ledermann, Jonathan A; Hawkes, David; Janes, Sam M; Devaraj, Anand

    2018-02-01

    To describe the radiological findings of radiation-induced lung damage (RILD) present on CT imaging of lung cancer patients 12 months after radical chemoradiation. Baseline and 12-month CT scans of 33 patients were reviewed from a phase I/II clinical trial of isotoxic chemoradiation (IDEAL CRT). CT findings were scored in three categories derived from eleven sub-categories: (1) parenchymal change, defined as the presence of consolidation, ground-glass opacities (GGOs), traction bronchiectasis and/or reticulation; (2) lung volume reduction, identified through reduction in lung height and/or distortions in fissures, diaphragm, anterior junction line and major airways anatomy, and (3) pleural changes, either thickening and/or effusion. Six patients were excluded from the analysis due to anatomical changes caused by partial lung collapse and abscess. All remaining 27 patients had radiological evidence of lung damage. The three categories, parenchymal change, shrinkage and pleural change were present in 100%, 96% and 82% respectively. All patients had at least two categories of change present and 72% all three. GGOs, reticulation and traction bronchiectasis were present in 44%, 52% and 37% of patients. Parenchymal change, lung shrinkage and pleural change are present in a high proportion of patients and are frequently identified in RILD. GGOs, reticulation and traction bronchiectasis are common at 12 months but not diagnostic. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Dislocation dynamics modelling of radiation damage in thin films

    International Nuclear Information System (INIS)

    Ferroni, Francesco; Tarleton, Edmund; Fitzgerald, Steven

    2014-01-01

    Transmission electron microscopy is a key tool for the extraction of information on radiation damage, the understanding of which is critical for materials development for nuclear fusion and fission reactors. Dislocations in TEM samples are subject to strong image forces, owing to the nanometric sample thicknesses, which may introduce artifacts in the damage analysis. Using dislocation dynamics, we elucidate the roles played by dislocation–surface interactions, dislocation–dislocation interactions and self-interactions due to climb for loop types observed in TEM. Comparisons with analytic solutions for a dislocation loop and an edge dislocation in a half-space are included, and the relationship between glide force and loop tilt examined. The parameters for convergence of the zero-traction boundary conditions are obtained, after which the evolution of dislocation structures in a thin film is studied. It is found that three main length scales govern the physical processes: the image force is governed by the distance of the loop from the surface and scales with the film thickness; the glide force is governed by the image stress as well as the loop–loop interaction stress which is in turn governed by the loop spacing L∼1/√ρ, where ρ is the loop density; finally, the climb force depends on the loop size. The three forces compete and their relative magnitudes define the evolution pathway of the dislocation structure. (paper)

  7. Perinatal radiation-induced renal damage in the beagle

    International Nuclear Information System (INIS)

    Jaenke, R.S.; Angleton, G.M.

    1990-01-01

    The developing perinatal kidney is particularly sensitive to radiation. The pathogenesis of the radiation-induced lesion is related to the destruction of outer cortical developing nephrons and direct radiation injury with secondary hemodynamic alterations in remnant nephrons. In this study, which is part of a life span investigation of the effects of whole-body gamma radiation during prenatal and early postnatal life, dogs were given 0, 0.16, 0.83, or 1.25 Gy irradiation at either 55 days postcoitus or 2 days postpartum and were examined morphometrically and histopathologically at 70 days of age. Although irradiated dogs showed no reduction in the total number of nephrons per kidney, there was a significant increase in the total number and relative percentage of immature, dysplastic glomeruli. In addition, deeper cortical glomeruli of irradiated kidneys exhibited mesangial sclerosis similar to that associated with progressive renal failure in our previous studies. These findings are in accord with those reported at doses of 2.24 to 3.57 Gy and demonstrate that the perinatal kidney is affected by radiation doses much lower than previously demonstrated

  8. Bystander effects: intercellular transmission of radiation damage signals

    Energy Technology Data Exchange (ETDEWEB)

    Little, J.B.; Azzam, E.I.; Toledo, S.M. de; Nagasawa, H

    2002-07-01

    Biological effects were examined in confluent cultures of fibroblasts and epithelial cells exposed to very low mean doses of alpha radiation, doses by which only 1-2% of the cells were actually traversed by an alpha particle. Enhanced frequencies of sister chromatid exchanges and HPRT mutations occurred in the non-irradiation, 'bystander' cells associated with a similar increase in the frequency of micronuclei, indicating the induction of DNA damage in these cells. In order to gain information concerning molecular pathways, changes in gene expression were examined in bystander cells by western analysis and in situ immunofluorescence staining. The expression levels of p53, p21 and MDM2 were significantly modulated in bystander cells: the damage signals leading to these changes were transmitted from irradiated to bystander cells by gap junction mediated intracellular communication. The bystander response was suppressed by incubation with superoxide dismutase as well as an inhibitor of NADPH oxidase, suggesting the effect may be mediated by oxidative stress. To examine other signalling pathways responsive to oxidative stress, the activation of stress-related kinases and their downstream transcription factors were analysed in bystander cells by western blotting and electrophoretic mobility shift assays: a 2-4 fold increase in the phosphorylation levels of JNK, EPK1/2, p90RSK, Elk-1 and ATF2 was observed. These changes were detected by 15 min after irradiation and persisted for at least 1 h. These findings indicate the activation of multiple signal transduction pathways in bystander cells, involving signals arising from the plasma membrane as well as from DNA damage. (author)

  9. 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

  10. Effect of substrate temperature on the radiation damage from MeV Si implantation in Si

    International Nuclear Information System (INIS)

    Yu, X.K.; Shao Lin; Rusakova, Irene; Wang, X.M.; Ma, K.B.; Chen, H.; Liu, Jiarui; Chu, W.-K.

    2006-01-01

    We have investigated the radiation damage by MeV implantation of Si in Si and its evolution under thermal annealing. Si wafers were implanted with MeV Si at various substrate temperatures. Damages were characterized by Rutherford-backscattering (RBS) channeling and by transmission electron microscopy (TEM). Defect formation after post-implantation annealing is very sensitive to the substrate temperatures during implantation. When the substrate temperature was decreased to 200 K, TEM revealed two distinct bands of damage after annealing: one around the mean projected ion range and another at half the projected range. Our study indicates that the formation of defects at half range results from the solid phase epitaxy growth of initial buried amorphous layers

  11. Factors influencing heterogeneity of radiation-induced DNA-damage measured by the alkaline comet assay

    Directory of Open Access Journals (Sweden)

    Seidel Clemens

    2012-04-01

    Full Text Available Abstract Background To investigate whether different conditions of DNA structure and radiation treatment could modify heterogeneity of response. Additionally to study variance as a potential parameter of heterogeneity for radiosensitivity testing. Methods Two-hundred leukocytes per sample of healthy donors were split into four groups. I: Intact chromatin structure; II: Nucleoids of histone-depleted DNA; III: Nucleoids of histone-depleted DNA with 90 mM DMSO as antioxidant. Response to single (I-III and twice (IV irradiation with 4 Gy and repair kinetics were evaluated using %Tail-DNA. Heterogeneity of DNA damage was determined by calculation of variance of DNA-damage (V and mean variance (Mvar, mutual comparisons were done by one-way analysis of variance (ANOVA. Results Heterogeneity of initial DNA-damage (I, 0 min repair increased without histones (II. Absence of histones was balanced by addition of antioxidants (III. Repair reduced heterogeneity of all samples (with and without irradiation. However double irradiation plus repair led to a higher level of heterogeneity distinguishable from single irradiation and repair in intact cells. Increase of mean DNA damage was associated with a similarly elevated variance of DNA damage (r = +0.88. Conclusions Heterogeneity of DNA-damage can be modified by histone level, antioxidant concentration, repair and radiation dose and was positively correlated with DNA damage. Experimental conditions might be optimized by reducing scatter of comet assay data by repair and antioxidants, potentially allowing better discrimination of small differences. Amount of heterogeneity measured by variance might be an additional useful parameter to characterize radiosensitivity.

  12. Factors influencing heterogeneity of radiation-induced DNA-damage measured by the alkaline comet assay

    International Nuclear Information System (INIS)

    Seidel, Clemens; Lautenschläger, Christine; Dunst, Jürgen; Müller, Arndt-Christian

    2012-01-01

    To investigate whether different conditions of DNA structure and radiation treatment could modify heterogeneity of response. Additionally to study variance as a potential parameter of heterogeneity for radiosensitivity testing. Two-hundred leukocytes per sample of healthy donors were split into four groups. I: Intact chromatin structure; II: Nucleoids of histone-depleted DNA; III: Nucleoids of histone-depleted DNA with 90 mM DMSO as antioxidant. Response to single (I-III) and twice (IV) irradiation with 4 Gy and repair kinetics were evaluated using %Tail-DNA. Heterogeneity of DNA damage was determined by calculation of variance of DNA-damage (V) and mean variance (Mvar), mutual comparisons were done by one-way analysis of variance (ANOVA). Heterogeneity of initial DNA-damage (I, 0 min repair) increased without histones (II). Absence of histones was balanced by addition of antioxidants (III). Repair reduced heterogeneity of all samples (with and without irradiation). However double irradiation plus repair led to a higher level of heterogeneity distinguishable from single irradiation and repair in intact cells. Increase of mean DNA damage was associated with a similarly elevated variance of DNA damage (r = +0.88). Heterogeneity of DNA-damage can be modified by histone level, antioxidant concentration, repair and radiation dose and was positively correlated with DNA damage. Experimental conditions might be optimized by reducing scatter of comet assay data by repair and antioxidants, potentially allowing better discrimination of small differences. Amount of heterogeneity measured by variance might be an additional useful parameter to characterize radiosensitivity

  13. Radiation damage of austenitic stainless steels and zirconium alloys; Pregled radijacionog ostecenja austenitnih nerdjajucih celika i legura cirkonijuma

    Energy Technology Data Exchange (ETDEWEB)

    Stefanovic, V [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

    1965-11-15

    This review contains analyses of available data concerning texture deformations and radiation damage of zirconium and zircaloy-2; radiation damage, influence of neutron radiation on the mechanical properties of austenitic, ferritic and other types of stainless steels.

  14. The alteration of chromatin domains during damage repair induced by ionizing radiation

    International Nuclear Information System (INIS)

    Cress, A.E.; Olson, K.M.; Olson, G.B.

    1995-01-01

    Several groups previously have reported the ability of chromatin structure to influence the production of damage induced by ionizing radiation. The authors' interest has been to determine whether chromatin structural alterations exist after ionizing radiation during a repair interval. The earlier work investigated this question using biochemical techniques. The crosslinking of nuclear structural proteins to DNA after ionizing radiation was observed. In addition, they found that the chromatin structure in vitro as measured by sucrose density gradient sedimentation, was altered after ionizing radiation. These observations added to earlier studies in which digital imaging techniques showed an alteration in feulgen-positive DNA after irradiation prompted the present study. The object of this study was to detect whether the higher order structure of DNA into chromatin domains within interphase human cells was altered in interphase cells in response to a radiation induced damage. The present study takes advantage of the advances in the detection of chromatin domains in situ using DNA specific dyes and digital image processing of established human T and B cell lines

  15. Field oxide radiation damage measurements in silicon strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Laakso, M [Particle Detector Group, Fermilab, Batavia, IL (United States) Research Inst. for High Energy Physics (SEFT), Helsinki (Finland); Singh, P; Shepard, P F [Dept. of Physics and Astronomy, Univ. Pittsburgh, PA (United States)

    1993-04-01

    Surface radiation damage in planar processed silicon detectors is caused by radiation generated holes being trapped in the silicon dioxide layers on the detector wafer. We have studied charge trapping in thick (field) oxide layers on detector wafers by irradiating FOXFET biased strip detectors and MOS test capacitors. Special emphasis was put on studying how a negative bias voltage across the oxide during irradiation affects hole trapping. In addition to FOXFET biased detectors, negatively biased field oxide layers may exist on the n-side of double-sided strip detectors with field plate based n-strip separation. The results indicate that charge trapping occurred both close to the Si-SiO[sub 2] interface and in the bulk of the oxide. The charge trapped in the bulk was found to modify the electric field in the oxide in a way that leads to saturation in the amount of charge trapped in the bulk when the flatband/threshold voltage shift equals the voltage applied over the oxide during irradiation. After irradiation only charge trapped close to the interface is annealed by electrons tunneling to the oxide from the n-type bulk. (orig.).

  16. Nuclear data for analysis of radiation damage processes

    International Nuclear Information System (INIS)

    Aruga, Takeo

    1999-01-01

    Parameters needed to analyze radiation damages for neutron irradiations are presented, taking iron samples irradiated with JMTR neutrons for an example. Special interests have been put on a comparison between results obtained by irradiations for one case with a full neutron spectrum and the other with a Cd-shielded neutron spectrum. A possibility is described that although atomic displacement rates for the two case differ only less than 2%, production rates of freely migrating defects can differ appreciably, due to recoiled atoms by (n, γ) reactions. More over, it is also suggested that although the median energy of PKA, defined as a PKA energy above (or below) which one half of the total atomic displacements are to be produced, may differ only slightly between the two cases, final radiation effects can be significantly different. The effects of charged particles emitted with high energies due to nucleon irradiations are stressed in relation to the significance of defects produced by PKAs with lower energies than several keV, especially for the case of irradiations with highly energetic nucleons as anticipated in GeV proton irradiations. (author)

  17. Nuclear data for analysis of radiation damage processes

    Energy Technology Data Exchange (ETDEWEB)

    Aruga, Takeo [Department of Materials Science Research, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)

    1999-03-01

    Parameters needed to analyze radiation damages for neutron irradiations are presented, taking iron samples irradiated with JMTR neutrons for an example. Special interests have been put on a comparison between results obtained by irradiations for one case with a full neutron spectrum and the other with a Cd-shielded neutron spectrum. A possibility is described that although atomic displacement rates for the two case differ only less than 2%, production rates of freely migrating defects can differ appreciably, due to recoiled atoms by (n, {gamma}) reactions. More over, it is also suggested that although the median energy of PKA, defined as a PKA energy above (or below) which one half of the total atomic displacements are to be produced, may differ only slightly between the two cases, final radiation effects can be significantly different. The effects of charged particles emitted with high energies due to nucleon irradiations are stressed in relation to the significance of defects produced by PKAs with lower energies than several keV, especially for the case of irradiations with highly energetic nucleons as anticipated in GeV proton irradiations. (author)

  18. Study of the radiation damage of silicon photomultipliers

    Energy Technology Data Exchange (ETDEWEB)

    Nitschke, Michael; Chmill, Valery; Garutti, Erika; Klanner, Robert; Schwandt, Joern [Institute for Experimental Physics, Hamburg University, Luruper Chaussee 149, D-22761 Hamburg (Germany)

    2016-07-01

    Radiation damage significantly changes the performance of silicon photomultipliers (SiPM). In this work, we first have characterized KETEK SiPMs with a pixel size of 15 x 15 μm{sup 2} using I-V (current-voltage), C/G-V/f (capacitance/impedance-voltage/frequency) and Q-V (charge-voltage) measurements with and without illumination with blue light of 470 nm from an LED. The SiPM parameters determined are DCR (dark count rate), relative PDE (photon detection efficiency), G (Gain), XT (cross-talk), Geiger breakdown characteristics, C{sub pix} (pixel capacitance) and R{sub q} (quenching resistance). Following this first characterization, the SiPMs were irradiated using reactor neutrons with fluences of 10{sup 9}, 10{sup 10}, 10{sup 11}, 5 . 10{sup 11}, and 10{sup 12} n/cm{sup 2}. Afterwards, the same measurements were repeated, and the dependence of the SiPM parameters on neutron fluence was determined. The results are used to optimize the radiation tolerance of SiPMs.

  19. Increase of radiation damage to potassium-ion permeability in E. coli cells with decrease in membrane fluidity

    International Nuclear Information System (INIS)

    Suzuki, S.

    1980-01-01

    Membrane lipids of an auxotroph of E. coli requiring unsaturated fatty acid were manipulated by supplementing the growth medium with unsaturated fatty acids of different chain lengths and/or configurations, and the radiation damage to K + -permeability of the resulting modified cells was investigated in relation with factors influencing membrane fluidity, such as temperature and procaine. Radiation had greater effects on membranes supplemented with unsaturated fatty acids of the trans configuration with a longer chain than on those of the cis configuration with a shorter chain. Radiation damage also increased with decrease in temperature. Furthermore, procaine-treated membranes showed increased resistance to radiation. All these results indicate that the damage was affected by the physical character of membrane lipids and that it was greater in membranes with decreased fluidity. (author)

  20. Multi-scale approach to radiation damage induced by ion beams: complex DNA damage and effects of thermal spikes

    International Nuclear Information System (INIS)

    Surdutovich, E.; Yakubovich, A.V.; Solov'yov, A.V.; Surdutovich, E.; Yakubovich, A.V.; Solov'yov, A.V.

    2010-01-01

    We present the latest advances of the multi-scale approach to radiation damage caused by irradiation of a tissue with energetic ions and report the calculations of complex DNA damage and the effects of thermal spikes on biomolecules. The multi-scale approach aims to quantify the most important physical, chemical, and biological phenomena taking place during and following irradiation with ions and provide a better means for clinically-necessary calculations with adequate accuracy. We suggest a way of quantifying the complex clustered damage, one of the most important features of the radiation damage caused by ions. This quantification allows the studying of how the clusterization of DNA lesions affects the lethality of damage. We discuss the first results of molecular dynamics simulations of ubiquitin in the environment of thermal spikes, predicted to occur in tissue for a short time after an ion's passage in the vicinity of the ions' tracks. (authors)

  1. Radiation Damage and Fission Product Release in Zirconium Nitride

    Energy Technology Data Exchange (ETDEWEB)

    Egeland, Gerald W. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States)

    2005-08-29

    Zirconium nitride is a material of interest to the AFCI program due to some of its particular properties, such as its high melting point, strength and thermal conductivity. It is to be used as an inert matrix or diluent with a nuclear fuel based on transuranics. As such, it must sustain not only high temperatures, but also continuous irradiation from fission and decay products. This study addresses the issues of irradiation damage and fission product retention in zirconium nitride through an assessment of defects that are produced, how they react, and how predictions can be made as to the overall lifespan of the complete nuclear fuel package. Ion irradiation experiments are a standard method for producing radiation damage to a surface for observation. Cryogenic irradiations are performed to produce the maximum accumulation of defects, while elevated temperature irradiations may be used to allow defects to migrate and react to form clusters and loops. Cross-sectional transmission electron microscopy and grazing-incidence x-ray diffractometry were used in evaluating the effects that irradiation has on the crystal structure and microstructure of the material. Other techniques were employed to evaluate physical effects, such as nanoindentation and helium release measurements. Results of the irradiations showed that, at cryogenic temperatures, ZrN withstood over 200 displacements per atom without amorphization. No significant change to the lattice or microstructure was observed. At elevated temperatures, the large amount of damage showed mobility, but did not anneal significantly. Defect clustering was possibly observed, yet the size was too small to evaluate, and bubble formation was not observed. Defects, specifically nitrogen vacancies, affect the mechanical behavior of ZrN dramatically. Current and previous work on dislocations shows a distinct change in slip plane, which is evidence of the bonding characteristics. The stacking-fault energy changes dramatically with

  2. Experimental studies of radiation damage of silicon detectors

    International Nuclear Information System (INIS)

    Angelescu, T.; Ghete, V.M.; Ghiordanescu, N.; Lazanu, I.; Mihul, A.; Golutvin, I.; Lazanu, S.; Savin, I.; Vasilescu, A.; Biggeri, U.; Borchi, E.; Bruzzi, M.; Li, Z.; Kraner, H.W.

    1994-02-01

    New particle physics experiments are correlated with high luminosity and/or high energy. The new generation of colliding beam machines which will be constructed will make an extrapolation of a factor of 100 in the center of mass energy and of 1000 in luminosity beyond present accelerators. The scientific community hopes that very exciting physics results could be achieved this way, from the solution to the problem of electroweak symmetry breaking to the possible discovery of new, unpredicted phenomena. The particles which compose the radiation field are: electrons, pions, neutrons, protons and photons. It has become evident that the problem of the radiation resistance of detectors in this severe environment is a crucial one. This situation is complicated more by the fact that detectors must work all the run time of the machine, and better all the time of the experiment, without replacement (part or whole). So, studies related to the investigation of the radiation hardness of all detector parts, are developing. The studies are in part material and device characterization after irradiation, and in part technological developments, made in order to find harder, cheaper technologies, for larger surfaces. Semiconductor detectors have proven to be a good choice for vertex and calorimeter. Both fixed target machines and colliders had utilized in the past silicon junction detectors as the whole or part of the detection system. Precision beam hodoscopes and sophisticated trigger devices with silicon are equally used. The associated electronics in located near the detectors, and is subjected to the same radiation fields. Studies of material and device radiation hardness are developing in parallel. Here the authors present results on the radiation hardness of silicon, both as a bulk material and as detectors, to neutron irradiation at high fluences

  3. Radiation damage in silicon. Defect analysis and detector properties

    International Nuclear Information System (INIS)

    Hoenniger, F.

    2008-01-01

    Silicon microstrip and pixel detectors are vital sensor-components as particle tracking detectors for present as well as future high-energy physics (HEP) experiments. All experiments at the large Hadron Collider (LHC) are equipped with such detectors. Also for experiments after the upgrade of the LHC (the so-called Super-LHC), with its ten times higher luminosity, or the planned International Linear Collider (ILC) silicon tracking detectors are forseen. Close to the interaction region these detectors have to face harsh radiation fields with intensities above the presently tolerable level. defect engineering of the used material, e. g. oxygen enrichment of high resistivity float zone silicon and growing of thin low resistivityepitaxial layers on Czochralski silicon substrates has been established to improve the radiation hardness of silicon sensors. This thesis focuses mainly on the investigation of radiation induced defects and their differences observed in various kinds of epitaxial silicon material. Comparisons with other materials like float zone or Czochralski silicon are added. Deep Level Transient Spectroscopy (DLTS) and Thermally Stimulated Current (TSC) measurements have been performed after γ-, electron-, proton- and neutron-irradiation. The differenced in the formation of vacancy and interstitial related defects as well as so-called clustered regions were investigated for various types of irradiation. In addition to the well known defects VO i , C i O i , C i C s , VP or V 2 several other defect complexes have been found and investigated. Also the material dependence of the defect introduction rates and the defect annealing behavior has been studied by isothermal and isochronal annealing experiments. Especially the IO 2 defect which is an indicator for the oxygen-dimer content of the material has been investigated in detail. On the basis of radiation induced defects like the bistable donor (BD) defect and a deep acceptor, a model has been introduced to

  4. Radiation damage in silicon. Defect analysis and detector properties

    Energy Technology Data Exchange (ETDEWEB)

    Hoenniger, F.

    2008-01-15

    Silicon microstrip and pixel detectors are vital sensor-components as particle tracking detectors for present as well as future high-energy physics (HEP) experiments. All experiments at the large Hadron Collider (LHC) are equipped with such detectors. Also for experiments after the upgrade of the LHC (the so-called Super-LHC), with its ten times higher luminosity, or the planned International Linear Collider (ILC) silicon tracking detectors are forseen. Close to the interaction region these detectors have to face harsh radiation fields with intensities above the presently tolerable level. defect engineering of the used material, e. g. oxygen enrichment of high resistivity float zone silicon and growing of thin low resistivityepitaxial layers on Czochralski silicon substrates has been established to improve the radiation hardness of silicon sensors. This thesis focuses mainly on the investigation of radiation induced defects and their differences observed in various kinds of epitaxial silicon material. Comparisons with other materials like float zone or Czochralski silicon are added. Deep Level Transient Spectroscopy (DLTS) and Thermally Stimulated Current (TSC) measurements have been performed after {gamma}-, electron-, proton- and neutron-irradiation. The differenced in the formation of vacancy and interstitial related defects as well as so-called clustered regions were investigated for various types of irradiation. In addition to the well known defects VO{sub i}, C{sub i}O{sub i}, C{sub i}C{sub s}, VP or V{sub 2} several other defect complexes have been found and investigated. Also the material dependence of the defect introduction rates and the defect annealing behavior has been studied by isothermal and isochronal annealing experiments. Especially the IO{sub 2} defect which is an indicator for the oxygen-dimer content of the material has been investigated in detail. On the basis of radiation induced defects like the bistable donor (BD) defect and a deep

  5. Influence of Hot Implantation on Residual Radiation Damage in Silicon Carbide

    International Nuclear Information System (INIS)

    Rawski, M.; Zuk, J.; Kulik, M.; Drozdziel, A.; Pyszniak, K.; Turek, M.; Lin, L.; Prucnal, S.

    2011-01-01

    Remarkable thermomechanical and electrical properties of silicon carbide (SiC) make this material very attractive for high-temperature, high-power, and high-frequency applications. Because of very low values of diffusion coefficient of most impurities in SiC, ion implantation is the best method to selectively introduce dopants over well-defined depths in SiC. Aluminium is commonly used for creating p-type regions in SiC. However, post-implantation radiation damage, which strongly deteriorates required electric properties of the implanted layers, is difficult to anneal even at high temperatures because of remaining residual damage. Therefore implantation at elevated target temperatures (hot implantation) is nowadays an accepted method to decrease the level of the residual radiation damage by avoiding ion beam-induced amorphization. The main objective of this study is to compare the results of the Rutherford backscattering spectroscopy with channeling and micro-Raman spectroscopy investigations of room temperature and 500 o C Al + ion implantation-induced damage in 6H-SiC and its removal by high temperature (up to 1600 o C) thermal annealing. (author)

  6. Grape (Vitis vinifera) extracts protect against radiation-induced oxidative stress and DNA damage

    International Nuclear Information System (INIS)

    Singha, Indrani; Das, Subir Kumar; Saxena, S.; Gautam, S.

    2016-01-01

    Ionizing radiation (IR) causes oxidative stress through the overwhelming generation of reactive oxygen species (ROS) in the living cells leading further to the oxidative damage to biomolecules. Grapes (Vitis vinifera) contain several bioactive phytochemicals and are the richest source of antioxidant. In this study, we investigated and compared in vitro antioxidant activity and DNA damage protective property of the grape extracts of four different cultivars, including the Thompson seedless, Flame seedless, Kishmish chorni and Red globe. The activities of ascorbic acid oxidase and catalase significantly (p<0.01) differed among extracts within the same cultivar, while that of peroxidase and polyphenol oxidase did not differ significantly among extracts of any cultivar. In vitro antioxidant activities were assessed by ferric-reducing antioxidant power (FRAP) assay and ABTS. The superoxide radical-scavenging activity was higher in the seed as compared to the skin or pulp of the same cultivar. DNA damage was evaluated in acellular system using pBR322 plasmid relaxation. Grape extract was able to effectively scavenge free radicals in vitro. It could significantly prevent radiation-induced DNA damage. Furthermore, the protective action of grape depends on the source of extract and type of the cultivars. (author)

  7. Characterization and calibration of radiation-damaged double-sided silicon strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kaya, L. [Institut für Kernphysik, Universität zu Köln, D-50937 Köln (Germany); Vogt, A., E-mail: andreas.vogt@ikp.uni-koeln.de [Institut für Kernphysik, Universität zu Köln, D-50937 Köln (Germany); Reiter, P.; Birkenbach, B.; Hirsch, R.; Arnswald, K.; Hess, H.; Seidlitz, M.; Steinbach, T.; Warr, N.; Wolf, K. [Institut für Kernphysik, Universität zu Köln, D-50937 Köln (Germany); Stahl, C.; Pietralla, N. [Institut für Kernphysik, Technische Universität Darmstadt, D-64291 Darmstadt (Germany); Limböck, T.; Meerholz, K. [Physikalische Chemie, Universität zu Köln, D-50939 Köln (Germany); Lutter, R. [Maier-Leibnitz-Laboratorium, Ludwig-Maximilians-Universität München, D-85748 Garching (Germany)

    2017-05-21

    Double-sided silicon strip detectors (DSSSD) are commonly used for event-by-event identification of charged particles as well as the reconstruction of particle trajectories in nuclear physics experiments with stable and radioactive beams. Intersecting areas of both p- and n-doped front- and back-side segments form individual virtual pixel segments allowing for a high detector granularity. DSSSDs are employed in demanding experimental environments and have to withstand high count rates of impinging nuclei. The illumination of the detector is often not homogeneous. Consequently, radiation damage of the detector is distributed non-uniformly. Position-dependent incomplete charge collection due to radiation damage limits the performance and lifetime of the detectors, the response of different channels may vary drastically. Position-resolved charge-collection losses between front- and back-side segments are investigated in an in-beam experiment and by performing radioactive source measurements. A novel position-resolved calibration method based on mutual consistency of p-side and n-side charges yields a significant enhancement of the energy resolution and the performance of radiation-damaged parts of the detector.

  8. Surface-structure dependence of healing radiation-damage mechanism in nanoporous tungsten

    Science.gov (United States)

    Duan, Guohua; Li, Xiangyan; Sun, Jingjing; Hao, Congyu; Xu, Yichun; Zhang, Yange; Liu, Wei; Liu, C. S.

    2018-01-01

    Under nuclear fusion environments, displacement damage in tungsten (W) is usually caused by neutrons irradiation through producing large quantities of vacancies (Vs) and self-interstitial atoms (SIAs). These defects not only affect the mechanical properties of W, but also act as the trap sites for implanted hydrogen isotopes and helium. Nano-porous (NP) W with a high fraction of free surfaces has been developed to mitigate the radiation damage. However, the mechanism of the surface reducing defects accumulation is not well understood. By using multi-scale simulation methods, we investigated the interaction of the SIA and V with different surfaces on across length and time scales. We found that, at a typical operation temperature of 1000 K, surface (1 1 0) preferentially heals radiation damage of W compared with surface (1 0 0) and boundary (3 1 0). On surface (1 1 0), the diffusion barrier for the SIA is only 0.68 eV. The annihilation of the SIA-V happens via the coupled motion of the V segregation towards the surface from the bulk and the two-dimensional diffusion of the SIA on the surface. Such mechanism makes the surface (1 1 0) owe better healing capability. On surface (1 0 0), the diffusion energy barrier for the SIA is 2.48 eV, higher than the diffusion energy barrier of the V in bulk. The annihilation of the SIA-V occurs via the V segregation and recombination. The SIA was found to migrate one-dimensionally along a boundary (3 1 0) with a barrier of 0.21 eV, leading to a lower healing efficiency in the boundary. This study suggested that the on-surface process plays an important role in healing radiation damage of NP W in addition to surface-enhanced diffusion and annihilation near the surface. A certain surface structure renders nano-structured W more radiation-tolerant.

  9. Report of the radiation group on radiation backgrounds and damage in the ISABELLE intersection regions

    International Nuclear Information System (INIS)

    Ludlam, T.; Kistiakowsky, V.; Toohig, T.E.

    1976-01-01

    The Radiation Group was charged to examine radiation aspects of the current ISABELLE design and the projected experimental arrangements. Some samples of questions to be addressed were: (1) how does the overall shielding design impact the experimental design, (2) what backgrounds might be expected from the proposed beam scraping, shaving, etc. schemes, (3) what are the radiation damage considerations for experimental electronics near the beam, and (4) what backgrounds might be expected in an experiment from operation of another experiment in the same or the adjacent intersection region. A review is given based on the ISABELLE Proposal, The Proceedings of the 1975 ISABELLE Summer Study, and the estimate of ISABELLE shielding requirements by Stevens and Thorndike

  10. (De)coupled zircon metamictization, radiation damage, and He diffusivity

    Science.gov (United States)

    Ault, A. K.; Guenthner, W.; Reiners, P. W.; Moser, A. C.; Miller, G. H.; Refsnider, K. A.

    2017-12-01

    We develop and apply a new protocol for targeting crystals for the zircon (U-Th)/He (He) thermochronometry to maximize effective U (eU) and corresponding closure temperature variability to develop zircon He date-eU correlations observed in some datasets. Our approach exploits visual proxies for radiation damage accumulation (metamictization) during zircon selection. We show that by purposefully targeting a spectrum of zircon textures from pristine to metamict grains, it is possible to generate broad eU variation in suites of zircon from a single sample and zircon He date-eU-metamictization trends that can be exploited to resolve increasingly complex thermal histories. We present plane light photographs, eU concentration, and zircon He results from 59 individual zircons from nine crystalline rock samples. Six of the nine samples come from exposed Proterozoic granitoids on SE Baffin Island, Canada; Boulder Creek, CO; Sandia Mountains, NM; and Mecca Hills, CA. We report data from three Archean Baffin samples to compare with the Proterozoic Baffin sample date-eU-metamictization trend. In each Proterozoic sample, target zircons display a spectrum of metamictization from pristine, transparent crystals to purple-brown, translucent grains. Progressive loss of transparency and increase in discoloration consistently corresponds to an increase in eU in all samples. Individual zircon eU varies from 89-1885 ppm and, within each sample, the total eU spread is 538 ppm to 1374 ppm. For any given eU value, the Archean zircon appear comparatively more metamict than the Proterozoic Baffin grains and samples collectively define a 1681 ppm range in eU, with more restrictive intrasample eU spreads (199-1120 ppm). Proterozoic samples from Baffin, Sandia, and Front Range yield negative zircon He date-eU correlations with intrasample date ranges of 90-783 Ma. Increasing eU and younger dates correspond with increasing metamictization. In contrast, all three Proterozoic Mecca Hills samples

  11. Low intensity microwave radiation induced oxidative stress, inflammatory response and DNA damage in rat brain.

    Science.gov (United States)

    Megha, Kanu; Deshmukh, Pravin Suryakantrao; Banerjee, Basu Dev; Tripathi, Ashok Kumar; Ahmed, Rafat; Abegaonkar, Mahesh Pandurang

    2015-12-01

    Over the past decade people have been constantly exposed to microwave radiation mainly from wireless communication devices used in day to day life. Therefore, the concerns over potential adverse effects of microwave radiation on human health are increasing. Until now no study has been proposed to investigate the underlying causes of genotoxic effects induced by low intensity microwave exposure. Thus, the present study was undertaken to determine the influence of low intensity microwave radiation on oxidative stress, inflammatory response and DNA damage in rat brain. The study was carried out on 24 male Fischer 344 rats, randomly divided into four groups (n=6 in each group): group I consisted of sham exposed (control) rats, group II-IV consisted of rats exposed to microwave radiation at frequencies 900, 1800 and 2450 MHz, specific absorption rates (SARs) 0.59, 0.58 and 0.66 mW/kg, respectively in gigahertz transverse electromagnetic (GTEM) cell for 60 days (2h/day, 5 days/week). Rats were sacrificed and decapitated to isolate hippocampus at the end of the exposure duration. Low intensity microwave exposure resulted in a frequency dependent significant increase in oxidative stress markers viz. malondialdehyde (MDA), protein carbonyl (PCO) and catalase (CAT) in microwave exposed groups in comparison to sham exposed group (pmicrowave exposed groups (pmicrowave exposed animal (pmicrowave exposed groups as compared to their corresponding values in sham exposed group (pmicrowave radiation induces oxidative stress, inflammatory response and DNA damage in brain by exerting a frequency dependent effect. The study also indicates that increased oxidative stress and inflammatory response might be the factors involved in DNA damage following low intensity microwave exposure. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Gymnemagenin-a triterpene saponin prevents γ-radiation induced cellular DNA damage

    International Nuclear Information System (INIS)

    Arunachalam, Kantha Deivi; Arun, Lilly Baptista; Annamalai, Sathesh Kumar; Hari, Shanmugasundaram

    2014-01-01

    Gymnema sylvestre an ethno-medicinally important plant was investigated for its protecting activity against radiation induced DNA damage. The major bioactive component present in Gymnema sylvestre such as gymnemic acid and gymnemagenin a triterpene saponin, were tested for its radioprotective effects against 60 Co irradiation induced DNA damage in fish model using fresh water fish Pangasius sutchi. Fishes subjected to a dose of 133 Gy of gamma radiation and observed for eight days. The genotoxic assessment by micronucleus assay showed us that that the plant extract helped in reducing the frequency of micronucleated and binucleated erythrocytes compared to the irradiated control group. The genotoxic assessment by alkaline comet assay by single gel electrophoresis shows that pretreatment with the plant extract appreciably decreased the percentage of tail DNA towards the levels close to those of normal control group. The gradual increase in the level of the antioxidant enzymes: superoxide dismutase (SOD) and catalase (CAT) during the course of the experiment indicates that the antioxidant enzyme activities play an important role in protecting organisms against gamma radiation-induced cellular oxidative stress. In conclusion the leaf extracts of Gymnema sylvstre exerts its radio protective potential by suppressing the toxic assault of ROS generated by the ionizing radiation through its ability to boost the levels of antioxidant enzymes (CAT and SOD) due to the presence of its phytochemicals like gymnemgenenin- a Triterpene Saponin. (author)

  13. 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

  14. 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.

  15. Comparison between cytogenetic damage induced in human lymphocytes by environmental chemicals or radiation

    Energy Technology Data Exchange (ETDEWEB)

    Cebulska-Wasilewska, A. [Institute of Nuclear Physics, Cracow (Poland)

    1997-12-31

    Author compared cytogenetic effects of chemicals (benzene and the member at benzene related compounds) and ionizing radiation on the human lymphocytes. Levels of various types of cytogenetic damage observed among people from petroleum plants workers groups are similar to the levels of damages detected in the blood of people suspected of the accidental exposure to a radiation source

  16. Comparison between cytogenetic damage induced in human lymphocytes by environmental chemicals or radiation

    International Nuclear Information System (INIS)

    Cebulska-Wasilewska, A.

    1997-01-01

    Author compared cytogenetic effects of chemicals (benzene and the member at benzene related compounds) and ionizing radiation on the human lymphocytes. Levels of various types of cytogenetic damage observed among people from petroleum plants workers groups are similar to the levels of damages detected in the blood of people suspected of the accidental exposure to a radiation source

  17. Radiation damage of UO{sub 2} fuel; Radijaciono ostecenje UO{sub 2} goriva

    Energy Technology Data Exchange (ETDEWEB)

    Stevanovic, M; Sigulinski, F [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

    1966-11-15

    Radiation damage study of fuel and fuel elements covers: study of radiation damage methods in Sweden; analysis of testing the fuel and fuel elements at the RA reactor; feasibility study of irradiation in the Institute compared to irradiation abroad in respect to the reactor possibilities. Tasks included in this study are relater to testing of irradiated UO{sub 2} and ceramic fuel elements.

  18. Design of offline measuring system for radiation damage effects on linear CCD

    International Nuclear Information System (INIS)

    Zhang Yong; Tang Benqi; Xiao Zhigang; Wang Zujun; Huang Fang; Huang Shaoyan

    2004-01-01

    The paper discusses the hardware design of offline measuring system for radiation damage effects on linear CCD. Some credible results were achieved by using this system. The test results indicate that the system is available for the study of the radiation damage effects on linear CCD. (authors)

  19. Radiation damage studies related to nuclear waste forms

    International Nuclear Information System (INIS)

    Gray, W.J.; Wald, J.W.; Turcotte, R.P.

    1981-12-01

    Much of the previously reported work on alpha radiation effects on crystalline phases of importance to nuclear waste forms has been derived from radiation effects studies of composite waste forms. In the present work, two single-phase crystalline materials, Gd 2 Ti 2 O 7 (pyrochlore) and CaZrTi 2 O 7 (zirconolite), of relative importance to current waste forms were studied independently by doping with 244 Cm at the 3 wt % level. Changes in the crystalline structure measured by x-ray diffraction as a function of dose show that damage ingrowth follows an expected exponential relationship of the form ΔV/V 0 = A[1-exp(-BD)]. In both cases, the materials became x-ray amorphous before the estimated saturation value was reached. The predicted magnitudes of the unit cell volume changes at saturation are 5.4% and 3.5%, respectively, for Gd 2 Ti 2 O 7 and CaZrTi 2 O 7 . The later material exhibited anisotropic behavior in which the expansion of the monoclinic cell in the c 0 direction was over five times that of the a 0 direction. The effects of transmutations on the properties of high-level waste solids have not been studied until now because of the long half-lives of the important fission products. This problem was circumvented in the present study by preparing materials containing natural cesium and then irradiating them with neutrons to produce 134 Cs, which has only a 2y half-life. The properties monitored at about one year intervals following irradiation have been density, leach rate and microstructure. A small amount of x-ray diffraction work has also been done. Small changes in density and leach rate have been observed for some of the materials, but they were not large enough to be of any consequence for the final disposal of high level wastes

  20. 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

  1. Radiation damage in natural and synthetic halite. Progress report January 1992 - February 1993

    International Nuclear Information System (INIS)

    Garcia Celma, A.

    1993-12-01

    This report complements the information presented in the report of December 1992 regarding the research performed at the ECN on radiation damage in salt. It consists of two parts. The first part regards the amount of stored energy which can be developed by gamma-irradiation on different types of halite and considers both the effect of low dose rates in developing radiation damage, and the possible saturation level of radiation damage in natural halite. The second part presents a model to simulate radiation damage development which incorporates some extensions in the Jain-Lidiard model. Due to malfunction of the Small Angle Neutron Scattering installation, neither the previously reported results nor the newly obtained can be trusted and therefore are not reported here. These results regard the shape, size and size distribution of radiation damage defects. (orig.)

  2. Clustered DNA damages induced in human hematopoietic cells by low doses of ionizing radiation

    Science.gov (United States)

    Sutherland, Betsy M.; Bennett, Paula V.; Cintron-Torres, Nela; Hada, Megumi; Trunk, John; Monteleone, Denise; Sutherland, John C.; Laval, Jacques; Stanislaus, Marisha; Gewirtz, Alan

    2002-01-01

    Ionizing radiation induces clusters of DNA damages--oxidized bases, abasic sites and strand breaks--on opposing strands within a few helical turns. Such damages have been postulated to be difficult to repair, as are double strand breaks (one type of cluster). We have shown that low doses of low and high linear energy transfer (LET) radiation induce such damage clusters in human cells. In human cells, DSB are about 30% of the total of complex damages, and the levels of DSBs and oxidized pyrimidine clusters are similar. The dose responses for cluster induction in cells can be described by a linear relationship, implying that even low doses of ionizing radiation can produce clustered damages. Studies are in progress to determine whether clusters can be produced by mechanisms other than ionizing radiation, as well as the levels of various cluster types formed by low and high LET radiation.

  3. Scopolamine methylbromide mitigates radiation induced damage and lethality in zebrafish

    International Nuclear Information System (INIS)

    Shrivastava, Nitisha; Joshi, Jayadev; Ghosh, Subhajit; Dimri, Manali; Prem Kumar, Indracanti; Sehgal, Neeta

    2014-01-01

    In view of the strategic importance radiation countermeasures hold, the present study was undertaken to screen a collection of small molecule clinical compounds for possible radioprotective action using zebrafish as a model system. Preliminary screening in developing zebrafish embryos (24 hour post fertilization, (hpf)) using damage manifestations and survival as end point identified scopolamine methylbromide (SMB), a muscarinic receptor antagonist, as a potential radiomitigator. It was found to be optimal (60% survival advantage after 6 th post irradiation day) at a dose of 80 μM when added 3 h post 20 Gy exposure. Mechanistic studies suggested that SMB though exhibited no significant antioxidant potential, but was found to limit radiation induced apoptosis (pre G1 population) quantified through flow cytometry (6 and 5% reduction after 8 or 24 h after treatments) and annexin V staining (8% reduction). Further, quantitative analysis, using caspase 3 assay, revealed a 2.46 fold increase in apoptosis in irradiated group and treatment of irradiated zebrafish embryos with SMB led to a significant reduction in global apoptosis (1.7 fold; p<0.05) when compared to irradiated group. In silico studies based on structural and functional similarity with known radioprotectors suggested similarities with atropine, a known anti-inflammatory agent with muscarinic antagonism and radioprotective potential. In view of this SMB was tested, in silico, for possible anti-inflammatory action. Molecular docking studies revealed that SMB interacts (B.E-8.0 Kcal/mole) with cycloxygenase-2 (COX-2). In lieu of this, anti-inflammation activity was assessed through ChIN (chemically induced inflammation) method in 3 dpf (days post fertilization) embryos and SMB was found to significantly inhibit inflammation at all doses studied from 20-200 μM at 3 and 6 hpi (hours post inflammation). Overall the result suggests that scopolamine methylbromide mitigates radiation induced injury and lethality in

  4. Radiation damage in diatomic materials at high doses

    International Nuclear Information System (INIS)

    Hobbs, L.W.; Hughes, A.E.

    1975-10-01

    Radiation effects in diatomic materials can differ structurally from those in metals because of the need to take into account different displacement rates on the two sublattices and the inevitable stoichiometric implications; in most diatomic insulators the anion species has the greater displacement cross section. Anion point defect stabilisation in heavily-irradiated (0.1 to 10 dpa) diatomic insulators has been studied using radiolysis of alkali and alkaline earth halides. A temperatures > 0.3 Tsub(m), all anion defects are mobile and can aggregate. Aggregation of anion interstitials results in creation of perfect dislocation loops without the need for primary cation displacements; simultaneous formation of substitutional anion molecular centres provides the necessary cation interstitials. Aggregation of anion vacancies leads to formation of metallic inclusions of the cation species, in some cases in an ordered array, which is the analogue, on a single sublattice, to the void lattice in metals. Availability of sinks for both anion interstitials and anion vacancies yields defect growth kinetics similar to those observed during formation of voids in irradiated metals, and a very high level of damage (approximately 10%) can be sustained in the lattice. The width of the temperature region concerned is much narrower, however, due to the possibility of recombination of aggregated or re-emitted anion vacancies with mobile or dispersed anion molecular defects; the latter can also aggregate to form fluid anion molecular inclusions and so complete the decomposition of the solid into separate phases of its constituent elements. (author)

  5. Radiation displacement damage estimates for a radionuclide waste stabilization material

    International Nuclear Information System (INIS)

    Dolan, K.W.

    1977-01-01

    Estimates of the number of atomic displacements produced in pollucite by the radioactive decay of Cs-134 are made. Pollucite is a candidate material for radionuclide waste stabilization, while Cs-134 is one of the radionuclide products which would be chemically bound in the pollucite lattice. At the maximum concentration of Cs-134 in pollucite, assuming a threshold displacement energy of 15.0 eV, the displacement rate is estimated to be 4.3 x 10 12 atoms/cm 3 /second which includes all atomic species in the pollucite lattice. It was found that most of the displacements, 85 percent, were caused by elastic scattering of photoelectrons and Compton electrons which are products of γ-ray interactions in the material. Most of the remaining displacements are caused by elastic scattering of β-particles. Recoil energies of the Ba daughter product are insufficient to cause displacement. Atomic displacements of nearest neighbors, atoms within one lattice spacing of the decay site, are estimated to be 2.7 x 10 6 atoms/cm 3 /second. These estimates provide a starting point for assessing the long term stability of pollucite to radiation damage

  6. Radiation damage to DNA in DNA-protein complexes.

    Science.gov (United States)

    Spotheim-Maurizot, M; Davídková, M

    2011-06-03

    The most aggressive product of water radiolysis, the hydroxyl (OH) radical, is responsible for the indirect effect of ionizing radiations on DNA in solution and aerobic conditions. According to radiolytic footprinting experiments, the resulting strand breaks and base modifications are inhomogeneously distributed along the DNA molecule irradiated free or bound to ligands (polyamines, thiols, proteins). A Monte-Carlo based model of simulation of the reaction of OH radicals with the macromolecules, called RADACK, allows calculating the relative probability of damage of each nucleotide of DNA irradiated alone or in complexes with proteins. RADACK calculations require the knowledge of the three dimensional structure of DNA and its complexes (determined by X-ray crystallography, NMR spectroscopy or molecular modeling). The confrontation of the calculated values with the results of the radiolytic footprinting experiments together with molecular modeling calculations show that: (1) the extent and location of the lesions are strongly dependent on the structure of DNA, which in turns is modulated by the base sequence and by the binding of proteins and (2) the regions in contact with the protein can be protected against the attack by the hydroxyl radicals via masking of the binding site and by scavenging of the radicals. 2011 Elsevier B.V. All rights reserved.

  7. A novel theory of radiation damage at high doses

    International Nuclear Information System (INIS)

    Seeger, A.; Stuttgart Univ.

    1989-01-01

    Deviations of radiation damage (in the case of metals usually monitored by the residual electrical resistivity) from proportionality with the irradiation dose have so far been analysed almost exclusively in terms of extensions of models originally developed for small doses. The present theory considers the opposite limit i.e. the quasi-saturated state. It is argued that at high doses the Lueck-Sizmann effect may result in a self-organization of clusters of vacancies and self-interstitials, forming a heterogeneous froth. Possible structures of this froth and its effect on the electrical resistivity of metals are discussed. The model is shown to account for the dependence of the ''saturation resistivity'' on the nature of the irradiation as well as for several other hitherto poorly explained observations. Among them are the electrical-resistivity variation induced by high-dose irradiation with heavy ions, the amorphization of certain alloys by high-dose electron irradiation, and the occurrence of ordered arrays of stacking-fault tetrahedra after in-situ irradiations in high-voltage electron microscopes. (author)

  8. A hybrid model of primary radiation damage in crystals

    International Nuclear Information System (INIS)

    Samarin, S.I.; Dremov, V.V.

    2009-01-01

    The paper offers a hybrid model which combines molecular dynamics and Monte Carlo (MD+MC) methods to describe primary radiation damage in crystals, caused by particles whose energies are no higher than several tens of keV. The particles are tracked in accord with equations of motion with account for pair interaction. The model also considers particle interaction with the mean-field potential (MFP) of the crystal. Only particles involved in cascading are tracked. Equations of motion for these particles include dissipative forces which describe energy exchange between cascade particles and electrons. New particles - the atoms of the crystal in the cascade region - have stochastic parameters (phase coordinates); they are sampled by the Monte Carlo method from the distribution that describes the classic canonical ensemble of non-interacting particles subjected to the external MFP. The introduction of particle interaction with the MFP helps avoid difficulties related to crystal stability and the choice of an adequate interparticle interaction potential in the traditional MD methods. Our technique is many times as fast as the traditional MD methods because we consider only particles which are involved in cascading and apply special methods to speedup the calculation of forces by accounting for the short-range pair potential used

  9. Monitoring radiation damage in the LHCb Silicon Tracker

    CERN Multimedia

    Graverini, Elena

    2018-01-01

    The purpose of LHCb is to search for indirect evidence of new physics in decays of heavy hadrons. The LHCb detector is a single-arm forward spectrometer with precise silicon-strip detectors in the regions with highest particle occupancies. The non-uniform exposure of the LHCb sensors makes it an ideal laboratory to study radiation damage effects in silicon detectors. The LHCb Silicon Tracker is composed of an upstream tracker, the TT, and of the inner part of the downstream tracker (IT). Dedicated scans are regularly taken, which allow a precise measurement of the charge collection efficiency (CCE) and the calibration of the operational voltages. The measured evolution of the effective depletion voltage $V_{depl}$ is shown, and compared with the Hamburg model prediction. The magnitudes of the sensor leakage current are also analysed and compared to their expected evolution according to phenomenological models. Our results prove that both the TT and the IT will withstand normal operation until the end of the L...

  10. 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)

  11. Neutron dosimetry for radiation damage in fission and fusion reactors

    International Nuclear Information System (INIS)

    Smith, D.L.

    1979-01-01

    The properties of materials subjected to the intense neutron radiation fields characteristic of fission power reactors or proposed fusion energy devices is a field of extensive current research. These investigations seek important information relevant to the safety and economics of nuclear energy. In high-level radiation environments, neutron metrology is accomplished predominantly with passive techniques which require detailed knowledge about many nuclear reactions. The quality of neutron dosimetry has increased noticeably during the past decade owing to the availability of new data and evaluations for both integral and differential cross sections, better quantitative understanding of radioactive decay processes, improvements in radiation detection technology, and the development of reliable spectrum unfolding procedures. However, there are problems caused by the persistence of serious integral-differential discrepancies for several important reactions. There is a need to further develop the data base for exothermic and low-threshold reactions needed in thermal and fast-fission dosimetry, and for high-threshold reactions needed in fusion-energy dosimetry. The unsatisfied data requirements for fission reactor dosimetry appear to be relatively modest and well defined, while the needs for fusion are extensive and less well defined because of the immature state of fusion technology. These various data requirements are examined with the goal of providing suggestions for continued dosimetry-related nuclear data research

  12. Contributions of each isotope in structural material on radiation damage in a hybrid reactor

    International Nuclear Information System (INIS)

    Günay, Mehtap

    2016-01-01

    In this study, the fluids were used in the liquid first-wall, blanket and shield zones of the designed hybrid reactor system. In this study, salt-heavy metal mixtures consisting of 93–85% Li_2_0Sn_8_0 + 5% SFG-PuO_2 and 2-10% UO_2, 93–85% Li_2_0Sn_8_0 + 5% SFG-PuO_2 and 2-10% NpO_2, and 93–85% Li_2_0Sn_8_0 + 5% SFG-PuO_2 and 2-10% UCO were used as fluids. In this study, the effect on the radiation damage of spent fuel-grade (SFG)-PuO_2, UO_2, NpO_2 and UCO contents was investigated in the structural material of a designed fusion–fission hybrid reactor system. In the designed hybrid reactor system were investigated the effect on the radiation damage of the selected fluid according to each isotopes of structural material in the structural material for 30 full power years (FPYs). Three-dimensional analyses were performed using the most recent MCNPX-2.7.0 Monte Carlo radiation transport code and the ENDF/B-VII.0 nuclear data library

  13. Characterization of ionizing radiation damage in DNA. Progress report, May 1, 1975--April 30, 1976

    International Nuclear Information System (INIS)

    Hawkins, R.B.

    1976-01-01

    The objective of this research is the characterization and quantitative assay of ionizing radiation-induced damage in DNA and nucleoprotein. Two lines of investigation have been pursued. The first is aimed at detection and assay of DNA to protein covalent cross linkage in coliphage T7. Protein and DNA are labeled with 14 C and 32 P, respectively. Cross linkage is assessed from the amount of labeled protein distributing like DNA and labeled DNA distributing like protein on a phenol-water countercurrent distribution system. It has been found that damage involving cross linkage occurs by two modes of radiation action in phage irradiated with 60 Co γ rays in .001M histidine medium. Indirect effects play a large role in one mode and direct effects play a large role in the other. In the second line of investigation, the hydrodynamic and viscoelastic properties of DNA from irradiated phage and cells will be examined to determine the extent to which DNA to DNA cross linkage and points of altered flexibility are introduced by radiation. An instrument for viscoelastic measurements has been constructed in preparation for these studies

  14. Molecular dynamics study of radiation damage and microstructure evolution of zigzag single-walled carbon nanotubes under carbon ion incidence

    Science.gov (United States)

    Li, Huan; Tang, Xiaobin; Chen, Feida; Huang, Hai; Liu, Jian; Chen, Da

    2016-07-01

    The radiation damage and microstructure evolution of different zigzag single-walled carbon nanotubes (SWCNTs) were investigated under incident carbon ion by molecular dynamics (MD) simulations. The radiation damage of SWCNTs under incident carbon ion with energy ranging from 25 eV to 1 keV at 300 K showed many differences at different incident sites, and the defect production increased to the maximum value with the increase in incident ion energy, and slightly decreased but stayed fairly stable within the majority of the energy range. The maximum damage of SWCNTs appeared when the incident ion energy reached 200 eV and the level of damage was directly proportional to incident ion fluence. The radiation damage was also studied at 100 K and 700 K and the defect production decreased distinctly with rising temperature because radiation-induced defects would anneal and recombine by saturating dangling bonds and reconstructing carbon network at the higher temperature. Furthermore, the stability of a large-diameter tube surpassed that of a thin one under the same radiation environments.

  15. Evaluation of DNA damage induced by gamma radiation in gill and muscle tissues of Cyprinus carpio and their relative sensitivity.

    Science.gov (United States)

    M K, Praveen Kumar; Shyama, Soorambail K; D'Costa, Avelyno; Kadam, Samit B; Sonaye, Bhagatsingh Harisingh; Chaubey, Ramesh Chandra

    2017-10-01

    The effect of radiation on the aquatic environment is of major concern in recent years. Limited data is available on the genotoxicity of gamma radiation on different tissues of aquatic organisms. Hence, the present investigation was carried out to study the DNA damage induced by gamma radiation in the gill and muscle tissues and their relative sensitivity using the comet assay in the freshwater teleost fish, common carp (Cyprinus carpio). The comet assay was optimized and validated in common carp using cyclophosphamide (CP), a reference genotoxic agent. The fish were exposed (acute) to various doses of gamma radiation (2, 4, 6, 8 and 10Gy) and samplings (gill and muscle tissue) were done at regular intervals (24, 48 and 72h) to assess the DNA damage. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA for all doses of gamma radiation in both tissues. We also observed a dose-related increase and a time-dependent decrease of DNA damage. In comparison, DNA damage showed different sensitivity among the tissues at different doses. This shows that a particular dose may have different effects on different tissues which could be due to physiological factors of the particular tissue. Our study also suggests that the gills and muscle of fish are sensitive and reliable tissues for evaluating the genotoxic effects of reference and environmental agents, using the comet assay. Copyright © 2017. Published by Elsevier Inc.

  16. Hollow-duct radiation delivery system investigation

    Directory of Open Access Journals (Sweden)

    Kramer D.

    2013-05-01

    Full Text Available Investigation of hollow-duct structure for high-power laser-diode-array radiation delivery into the end-pumped large-aperture gain media is reported. A ray tracing method has been used to evaluate the performance of the structure designed for maximum transmission efficiency and output beam profile homogeneity. Variable hollow-duct lengths as well as emanating angles of laser-diode-array have been taken into account.

  17. Cytogenetic damage at low doses and the problem of bioindication of chronic low level radiation exposure

    International Nuclear Information System (INIS)

    Geras'kin, S.A.; Dikarev, V.G.; Nesterov, E.B.; Vasiliev, D.V.; Dikareva, N.S.

    2000-01-01

    radioactive wastes located at Sosnovy Bor in the Leningrad region was carried out in 1995-1999. Results of this research give evidence on pronounced genotoxic influence presence in investigated sites and as against the 30-km ChNPP zone in the Sosnovy Bor region chemical toxicants make the significant contribution to pollution of the environment. The seeds collected in control and experimental population were compared by acute γ-irradiation resistance. This comparison has revealed the selection toward the increase of repair system efficiency. The received results give evidence that although the cytogenetic damage frequency within low dose range cannot be used in biological dosimetry, but the indexes based on it are informative and important for the man-made effect bioindication and for identification of groups at risk of long term health consequences of radiation. (author)

  18. Radiation damage related to fusion-reactor materials

    International Nuclear Information System (INIS)

    Brimhall, J.L.

    1982-03-01

    Three reasons why the fusion irradiation environment could produce different damage microstructure will be discussed: (1) the primary damage state induced by a higher energy primary knock-on-spectra; (2) increased helium generation due to high eta, α cross sections; and (3) pulsed operation of the irradiation environment. Examples of the microstructural damage caused by each of the above will be given

  19. 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

  20. Post-irradiation dietary vitamin E does not affect the development of radiation-induced lung damage in rats

    NARCIS (Netherlands)

    Wiegman, EA; van Gameren, MA; Kampinga, HH; Szabo, BG; Coppes, RP

    The purpose of this study was to investigate whether application of post-irradiation vitamin E, an anti-oxidant, could prevent the development of radiation induced lung damage. Wistar rats were given vitamin E enriched or vitamin E deprived food starting from 4 weeks after 18 Gy single dose

  1. Radiation Dosimetry Management: Quality Assurance and Investigations

    International Nuclear Information System (INIS)

    Perle, S.

    2001-01-01

    Full text: In a litigation-prone society, it is prudent for any business to evaluate its potential exposure to legal action, initiated by either an employee or a member of the general public. This potential is exacerbated when the phobia of radiation exposure and radioactive materials is interjected into the equation. This phobia is fuelled by the perceived risks of radiation exposure, be they fact or fantasy. With the current cancer incidence rate being approximately 1 in every 2.5 individuals (for all types of cancer), it is imperative that all facilities take a proactive look at their business vulnerability. When radiation exposure is the issue, records documentation is a critical factor, and a significant amount of effort should be expended to implement a comprehensive records management system. A comprehensive Radiation Dosimetry Management Program is essential if a business is going to mitigate any regulatory or legal intervention. This lecture will address appropriate Records Quality Assurance, and, the appropriate requirements for investigations of dosimetry results. (author)

  2. High resolution transmission electron microscopy and microdiffraction for radiation damage analysis

    International Nuclear Information System (INIS)

    Sinclair, R.

    1982-01-01

    High resolution TEM techniques have developed to quite a sophisticated level over the past few years. In addition TEM instruments with a scanning capability have become available commercially which permit in particular the formation of a small electron probe at the specimen. Thus direct resolution and microdiffraction investigations of thin specimens are now possible, neither of which have been employed to any great extent in the analysis of radiation damage. Some recent advances which are thought to be relevant to this specific area of research are highlighted

  3. Annealing of natural metamict zircons. I low degree of radiation damage

    CERN Document Server

    Colombo, M

    1998-01-01

    In-situ time dependent high temperature X-ray powder diffraction was used to investigate the ordering process occurring during annealing of natural zircons with a low degree of radiation damage. It was possible to distinguish two stages of this process. Firstly, the diffusion of defects induced by alpha-particles, this stage contributes only to a certain degree of relaxation in the unit cell. In the second stage there is some degree of recrystallization. A hkl-dependence in the variation of the integrated intensity is observed and the increase in the volume of crystalline zircon is therefore related to a process of migration of dislocations.

  4. Modulation of radiation induced DNA damage by natural products in hemopoietic tissue of mice

    International Nuclear Information System (INIS)

    Jayakumar, S.; Bhilwade, H.N.; Chaubey, R.C.

    2014-01-01

    Ionizing radiation is known to induce oxidative stress through generation of ROS leading to a variety of DNA lesions. However, the most dangerous DNA lesions which are responsible for the origin of lethal effects, mutagenesis, genomic instability and carcinogenesis are the DSBs. During recent years efforts are being made to identify phytochemicals, antioxidants or neutraxeuticals which can reduce harmful effect of radiation during accidental exposure or prevent normal tissue injury during radiotherapy. In the present study, we have investigated the radioprotective role of curcumin, a dietary antioxidant, taurine, malabaricone-C, and umbelliferone, for their radioprotective properties in hemopoietic cells of mice. Groups of mice-were fed 1% of curcumin in diet for three weeks. Similarly other groups of mice were injected i.p. with 50 mg/kg body weight of taurine for five consecutive days. After the completion of the treatment mice pre-treated with curcumin and taurine were exposed to 3 Gy of gamma rays. Malabaricone-C was tested for its radiomodulation potential in vitro, in spleenocytes of mouse. Spleenocytes were isolated and treated with different concentrations (0.5-25 ìM) of malabaricone-C. Immediately after irradiation, alkaline comet assay were performed using standard procedures. Twenty four post radiation exposure mice were sacrificed for micronucleus test. Results of these studies showed significant reduction in DNA damage by curcumin. The micronucleus data showed marginal increase in the frequency of micronucleated erythrocytes in curcumin fed group as compared to the controls. Mice receiving curcumin for 3 weeks in diet followed by gamma radiation (3 Gy), showed approximately 50% reduction in the frequency of micro nucleated polychromatic erythrocytes. Pre-treatment of mice with taurine significantly (p < 0.01) reduced the frequency of gamma rays induced mn-PCEs in bone marrow tissue. Malabaricone-C at 1.5 ìM concentration showed very good protection

  5. Wheat Germ Oil Attenuates Gamma Radiation- Induced Skeletal Muscles Damage in Rats

    International Nuclear Information System (INIS)

    Said, U.Z.; Saada, H.N.; Shedid, Sh.M.; Mahdy, E.M.E.; Shousha, W.Gh.

    2008-01-01

    Muscular strength is important in sport as well as in daily activities. Exposure to ionizing radiation is thought to increase oxidative stress and damage muscle tissue. Wheat germ oil is a natural unrefined vegetable oil. It is an excellent source of vitamin E, octacosanol, linoleic and linolenic essential fatty acids, which may be beneficial in neutralizing the free oxygen radicals. The present study was designed to investigate the efficacy of wheat germ oil, on radiation-induced oxidative damage in rats skeletal muscle. Wheat germ oil was supplemented orally via gavages to rats at a dose of 54 mg/ kg body weight/day for 14 successive days pre- and 7 post-exposure to 5 Gy (one shot dose) of whole body gamma irradiation. Animals were sacrificed 7, 14 and 21 days post radiation exposure. The results revealed that whole body gamma-irradiation of rats induces oxidative stress in skeletal muscles obvious by significant elevation in the level of thiobarbituric acid reactive substances (TBARS) associated with significant decreases in the content of reduced glutathione (GSE1), as well as decreases in superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities. Irradiated rats showed, also, significant decreases in creatine phosphokinase (CPK), glutamate dehydrogenase (GDH) and glucose-6-phosphate dehydrogenase (G-6-PD) activities. Furthermore, total iron, total copper and total calcium levels were significantly increased in skeletal muscles of irradiated rats group compared to control group. Wheat germ oil treated-irradiated rats showed significantly less sever damage and remarkable improvement in all the measured parameters, compared to irradiated rats. It could be concluded that wheat germ oil by attenuating radiation induced oxidative stress might play a role in maintaining skeletal muscle integrity

  6. Development of radiation biological dosimetry and treatment of radiation-induced damaged tissue

    International Nuclear Information System (INIS)

    Cho, Chul Koo; Kim, Tae Hwan; Lee, Yun Sil

    2000-04-01

    Util now, only a few methods have been developed for radiation biological dosimetry such as conventional chromosome aberration and micronucleus in peripheral blood cell. However, because these methods not only can be estimated by the expert, but also have a little limitation due to need high technique and many times in the case of radiation accident, it is very difficult to evaluate the absorbed dose of victims. Therefore, we should develop effective, easy, simple and rapid biodosimetry and its guideline(triage) to be able to be treated the victims as fast as possible. We established the apoptotic fragment assay, PCC, comet assay, and micronucleus assay which was the significant relationship between dose and cell damages to evaluate the irradiated dose as correct and rapid as possible using lymphocytes and crypt cells, and compared with chromosome dosimetry and micronucleus assay

  7. Development of radiation biological dosimetry and treatment of radiation-induced damaged tissue

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Chul Koo; Kim, Tae Hwan; Lee, Yun Sil [and others

    2000-04-01

    Util now, only a few methods have been developed for radiation biological dosimetry such as conventional chromosome aberration and micronucleus in peripheral blood cell. However, because these methods not only can be estimated by the expert, but also have a little limitation due to need high technique and many times in the case of radiation accident, it is very difficult to evaluate the absorbed dose of victims. Therefore, we should develop effective, easy, simple and rapid biodosimetry and its guideline(triage) to be able to be treated the victims as fast as possible. We established the apoptotic fragment assay, PCC, comet assay, and micronucleus assay which was the significant relationship between dose and cell damages to evaluate the irradiated dose as correct and rapid as possible using lymphocytes and crypt cells, and compared with chromosome dosimetry and micronucleus assay.

  8. Reductive effects of poria cocos on radiation-induced damage

    International Nuclear Information System (INIS)

    Oh, Heon; Park, Hae-Ran; Jo, Sung-Kee; Kim, Sung-Ho

    2002-01-01

    In order to screen a radioprotective material from nontoxic natural products, the effects of Poria cocos (PC), known as a blood tonic of traditional Oriental herbs, were investigated in HL-60 cells and ICR mice. The water extract of PC was administrated to mice and then the mice were irradiated with - rays. The jejunal crypt survival, endogenous spleen colony formation and apoptosis in jejunal crypt cells were investigated in mice irradiated with 12 Gy, 6.5 Gy, 2 Gy of -rays, respectively. The administration of the PC extract protected the jejunal crypts (p<0.005) and decreased the apoptosis frequency (p<0.05). The formation of endogenous spleen colony was increased but not significantly. The micronuclei (MN) formation and the alkaline single-cell gel electrophoresis (SCGE; comet assay) were investigated in HL- 60 cells irradiated 2 Gy of -rays. The frequency of MN was decreased (p<0.001) and the tail movement, which was a marker of DNA strand breaks in the SCGE, was decreased in groups treated with PC extract (p<0.01) before exposure to-irradiation. These results indicated that PC protects stem cells and reduces DNA damage induced by -rays. Therefore, Poria cocos might be a useful radioprotector, especially since it is a relatively nontoxic product

  9. Comparison of damage induced by mercury chloride and ionizing radiation in the susceptible rat model

    International Nuclear Information System (INIS)

    Kim, Ji Hyang; Yoon, Yong Dal; Kim, Jin Kyu

    2003-01-01

    Mercury (Hg), one of the most diffused and hazardous organ-specific environmental contaminants, exists in a wide variety of physical and chemical states. Although the reports indicate that mercury induces a deleterious damage, little has been reported from the investigations of mercury effects in living things. The purpose of this study is to evaluate the effects of mercury chloride and ionizing radiation. Prepubertal male F-344 rats were administered mercury chloride in drinking water throughout the experimental period. Two weeks after whole body irradiation, organs were collected for measuring the induced injury. Serum levels of GOT, GPT, ALP, and LDH were checked in the experimental groups and the hematological analysis was accomplished in plasma. In conclusion, the target organ of mercury chloride seems to be urinary organs and the pattern of damage induced by mercury differs from that of the irradiated group

  10. Analytical studies into radiation-induced starch damage in black and white peppers

    International Nuclear Information System (INIS)

    Sharif, M.M.; Farkas, J.

    1993-01-01

    Temperature dependence of the apparent viscosity of heat-generalized suspensions of untreated and irradiated pepper samples has been investigated. There was a close linear correlation between the logarithm of ''fluidity'' (reciprocal of the apparent viscosity) and the reciprocal absolute temperature of the measurement. The slope of the regression line (the temperature dependence of fluidity) increased with the radiation dose. Gelatinization thermograms of aqueous suspensions of ground pepper samples were obtained by differential scanning calorimetry. Temperature characteristics of heat-gelatinization endotherms showed no significant differences between untreated and irradiated samples. A calorimetric method for damaged starch, the estimation of reducing power, and the alcohol-induced turbidity of aqueous extracts showed statistically significant increases of starch damage at doses higher than 4 kGy. These indices of starch-depolymerization have been changed less dramatically by irradiation than the apparent viscosity of the heat-gelatinized suspensions. (author)

  11. Fast heavy-ion radiation damage of glycine in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, Shinji [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Tsuchida, Hidetsugu, E-mail: tsuchida@nucleng.kyoto-u.ac.jp [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Quantum Science and Engineering Center, Kyoto University, Uji 611-0011 (Japan); Furuya, Ryosuke [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Majima, Takuya; Itoh, Akio [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Quantum Science and Engineering Center, Kyoto University, Uji 611-0011 (Japan)

    2016-12-15

    Fast heavy-ion radiolysis of biomolecules in aqueous solution is investigated for an atomistic understanding of radiation damage to normal cells during heavy-particle beam therapy. The smallest amino acid glycine was used as a model biomaterial. Microjets of aqueous glycine solutions under vacuum were irradiated with 4.0-MeV carbon ions corresponding to energies in the Bragg peak region. To understand the effects of the water environment on molecular damage, the yield of glycine dissociation was measured by secondary ion mass spectroscopy. The yield was significantly reduced relative to gas-phase glycine targets. This implies that the numerous water molecules surrounding a single glycine molecule act as a buffer that suppresses dissociation. This is an environmental effect similar to that observed for other biomolecular cluster targets.

  12. Survey of Damage Investigation of Babbitted Industrial Bearings

    Directory of Open Access Journals (Sweden)

    Lyle A. Branagan

    2015-04-01

    Full Text Available This survey collects the efforts to understand the sources and consequences of damage to babbitted industrial bearings, which operate by means of a hydrodynamic, or hydrostatic, film. Major individual damage types are discussed in the context of major damage categories.

  13. Investigation of retinal damage during refractive eye surgery

    Science.gov (United States)

    Schumacher, S.; Sander, M.; Dopke, C.; Grone, A.; Ertmer, W.; Lubatschowski, H.

    2005-04-01

    Ultrashort laser pulses are increasingly used in refractive eye surgery to cut inside transparent corneal tissue. This is exploited by the fs-LASIK procedure which affords the opportunity to correct ametropia without any mechanical effects. The cutting process is caused by the optical breakdown occurring in the laser focus. During this process only a certain amount of the pulse energy is deposited into the tissue. The remaining pulse energy propagates further through the eye and interacts with the retina and the strong absorbing tissue layers behind. Therefore this investigation shall clarify if the intensity of the remaining laser pulse and the resulting temperature field can damage the retina and the surrounding tissue. Threshold values of the retinal tissue and theoretical calculations of the temperature field will be presented.

  14. Radiation damage calculations for the APT materials test program

    International Nuclear Information System (INIS)

    Corzine, R.K.; Wechsler, M.S.; Dudziak, D.J.; Ferguson, P.D.; James, M.R.

    1999-01-01

    A materials irradiation was performed at the Los Alamos Neutron Science Center (LANSCE) in the fall of 1996 and spring of 1997 in support of the Accelerator Production of Tritium (APT) program. Testing of the irradiated materials is underway. In the proposed APT design, materials in the target and blanket are to be exposed to protons and neutrons over a wide range of energies. The irradiation and testing program was undertaken to enlarge the very limited direct knowledge presently available of the effects of medium-energy protons (∼1 GeV) on the properties of engineering materials. APT candidate materials were placed in or near the LANSCE accelerator 800-MeV, 1-mA proton beam and received roughly the same proton current density in the center of the beam as would be the case for the APT facility. As a result, the proton fluences achieved in the irradiation were expected to approach the APT prototypic full-power-year values. To predict accurately the performance of materials in APT, radiation damage parameters for the materials experiment must be determined. By modeling the experiment, calculations for atomic displacement, helium and hydrogen cross sections and for proton and neutron fluences were done for representative samples in the 17A, 18A, and 18C areas. The LAHET code system (LCS) was used to model the irradiation program, LAHET 2.82 within LCS transports protons > 1 MeV, and neutrons >20 MeV. A modified version of MCNP for use in LCS, HMCNP 4A, was employed to tally neutrons of energies <20 MeV

  15. Radiation damage in Fe-Cr alloys: Atomistic studies

    International Nuclear Information System (INIS)

    Terentyev, Dmitry; Malerba, Lorenzo; Bonny, Giovanni; Castin, Nicolas

    2009-01-01

    High-Cr ferritic-martensitic steels are the most promising candidate structural materials for future advanced fission reactors, as well as for fusion systems, due to their better thermomechanical properties and higher radiation resistance as compared to austenitic steels. The performance of these steels, especially under irradiation, appears to be largely determined by the Cr content. For instance, the current choice of steel compositions around ∼9 wt% Cr is mainly based on the observation of a local minimum in the ductile-brittle transition temperature shift at this composition. On the other hand, reduced void swelling is observed between 3 and 12 wt% Cr. The origin of these and other Cr-dependent effects remained unexplained for a long time, thereby calling for a physical modelling effort addressing these questions. In this presentation, an overview is given on the effort made in recent years to construct a whole modelling framework, from ab initio to dislocations, to provide explanations to the above-mentioned issues. Ab initio calculations combined to the development of the interatomic potentials capable of grasping key features of Cr atoms embedded in perfect and defected Fe matrix, were required. Primary damage, defect migration, Cr mass transport, phase separation, Cr-defect segregation and dislocation-defect interactions could then be studied using fully atomistic approaches. Our research shows that many of the effects of Cr content on the behaviour of these alloys under irradiation can be attributed to the only recently highlighted high solubility of Cr in Fe (∼10 wt%), below which, in addition, Cr atoms tend to order. The presentation will clarify how this aspect, combined with the high affinity between Cr atoms and self-interstitials defects, influences and partly explain both microstructure evolution and mechanical behaviour of high-Cr steels under irradiation. (author)

  16. DNA Damage in Melania Snail (Semisulcospira libertine) Irradiated with Gamma Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Tae Ho; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Advanced Radiation Technology Institute, Jeongeup (Korea, Republic of); An, Kwang Guk [Chungnam National University, Daejeon (Korea, Republic of); Nili, Mohammad [Dawnesh Radiation Research Institute, Barcelona (Spain)

    2010-10-15

    Generally radiological protection has focused on human. But International Commission on Radiological Protection (ICRP) requires the effect data of ionizing radiation on nonhuman biota for the radiological protection of the environment. The choice of a melania snail as a model for environmental biomonitoring of radiation genotoxicity took into account that invertebrates represent one of aquatic species. The comet assay or single cell gel electrophoresis (SCGE) assay, first introduced by Ostling and Johanson, was used to detect DNA single strand breaks and to investigate the application of this technique as a tool for aquatic biomonitoring. Comet assay offers considerable advantages over some other assays used in DNA damage detection, such as chromosomal aberrations, sister chromatid Exchange and the micronucleus test, since there is no need for cells to be in a dividing state. Other advantages are its rapidity, relatively low coast, and wide applicability to virtually any nucleated cell type. In this study, we evaluated DNA damage in cells of Semisulcospira libertina after irradiation with {sup 60}Co gamma radiation by using the comet assay

  17. Radiation damage in room-temperature data acquisition with the PILATUS 6M pixel detector.

    Science.gov (United States)

    Rajendran, Chitra; Dworkowski, Florian S N; Wang, Meitian; Schulze-Briese, Clemens

    2011-05-01

    The first study of room-temperature macromolecular crystallography data acquisition with a silicon pixel detector is presented, where the data are collected in continuous sample rotation mode, with millisecond read-out time and no read-out noise. Several successive datasets were collected sequentially from single test crystals of thaumatin and insulin. The dose rate ranged between ∼ 1320 Gy s(-1) and ∼ 8420 Gy s(-1) with corresponding frame rates between 1.565 Hz and 12.5 Hz. The data were analysed for global radiation damage. A previously unreported negative dose-rate effect is observed in the indicators of global radiation damage, which showed an approximately 75% decrease in D(1/2) at sixfold higher dose rate. The integrated intensity decreases in an exponential manner. Sample heating that could give rise to the enhanced radiation sensitivity at higher dose rate is investigated by collecting data between crystal temperatures of 298 K and 353 K. UV-Vis spectroscopy is used to demonstrate that disulfide radicals and trapped electrons do not accumulate at high dose rates in continuous data collection.

  18. Radiation damage in room-temperature data acquisition with the PILATUS 6M pixel detector

    Energy Technology Data Exchange (ETDEWEB)

    Rajendran, Chitra, E-mail: chitra.rajendran@psi.ch; Dworkowski, Florian S. N.; Wang, Meitian; Schulze-Briese, Clemens [Swiss Light Source at Paul Scherrer Institute, CH-5232 Villigen (Switzerland)

    2011-05-01

    Observations of the dose-rate effect in continuous X-ray diffraction data acquisition at room temperature are presented. The first study of room-temperature macromolecular crystallography data acquisition with a silicon pixel detector is presented, where the data are collected in continuous sample rotation mode, with millisecond read-out time and no read-out noise. Several successive datasets were collected sequentially from single test crystals of thaumatin and insulin. The dose rate ranged between ∼1320 Gy s{sup −1} and ∼8420 Gy s{sup −1} with corresponding frame rates between 1.565 Hz and 12.5 Hz. The data were analysed for global radiation damage. A previously unreported negative dose-rate effect is observed in the indicators of global radiation damage, which showed an approximately 75% decrease in D{sub 1/2} at sixfold higher dose rate. The integrated intensity decreases in an exponential manner. Sample heating that could give rise to the enhanced radiation sensitivity at higher dose rate is investigated by collecting data between crystal temperatures of 298 K and 353 K. UV-Vis spectroscopy is used to demonstrate that disulfide radicals and trapped electrons do not accumulate at high dose rates in continuous data collection.

  19. Analysis of ionizing radiation-induced foci of DNA damage repair proteins

    International Nuclear Information System (INIS)

    Veelen, Lieneke R. van; Cervelli, Tiziana; Rakt, Mandy W.M.M. van de; Theil, Arjan F.; Essers, Jeroen; Kanaar, Roland

    2005-01-01

    Repair of DNA double-strand breaks by homologous recombination requires an extensive set of proteins. Among these proteins are Rad51 and Mre11, which are known to re-localize to sites of DNA damage into nuclear foci. Ionizing radiation-induced foci can be visualized by immuno-staining. Published data show a large variation in the number of foci-positive cells and number of foci per nucleus for specific DNA repair proteins. The experiments described here demonstrate that the time after induction of DNA damage influenced not only the number of foci-positive cells, but also the size of the individual foci. The dose of ionizing radiation influenced both the number of foci-positive cells and the number of foci per nucleus. Furthermore, ionizing radiation-induced foci formation depended on the cell cycle stage of the cells and the protein of interest that was investigated. Rad51 and Mre11 foci seemed to be mutually exclusive, though a small subset of cells did show co-localization of these proteins, which suggests a possible cooperation between the proteins at a specific moment during DNA repair

  20. Computer simulation of radiation damage in NaCl using a kinetic rate reaction model

    International Nuclear Information System (INIS)

    Soppe, W.J.

    1993-01-01

    Sodium chloride and other alkali halides are known to be very susceptible to radiation damage in the halogen sublattice when exposed to ionizing radiation. The formation of radiation damage in NaCl has generated interest because of the relevance of this damage to the disposal of radioactive waste in rock salt formations. In order to estimate the long-term behaviour of a rock salt repository, an accurate theory describing the major processes of radiation damage in NaCl is required. The model presented in this paper is an extended version of the Jain-Lidiard model; its extensions comprise the effect of impurities and the colloid nucleation stage on the formation of radiation damage. The new model has been tested against various experimental data obtained from the literature and accounts for several well known aspects of radiation damage in alkali halides which were not covered by the original Jain-Lidiard model. The new model thus may be expected to provide more reliable predictions for the build-up of radiation damage in a rock salt nuclear waste repository. (Author)

  1. Thermal annealing of radiation damage in CMOS ICs in the temperature range -140 C to +375 C

    Science.gov (United States)

    Danchenko, V.; Fang, P. H.; Brashears, S. S.

    1982-01-01

    Annealing of radiation damage was investigated in the commercial, Z- and J-processes of the RCA CD4007A ICs in the temperature range from -140 C to +375 C. Tempering curves were analyzed for activation energies of thermal annealing, following irradiation at -140 C. It was found that at -140 C, the radiation-induced shifts in the threshold potentials were similar for all three processes. The radiation hardness of the Z- and J-process is primarily due to rapid annealing of radiation damage at room temperature. In the region -140 to 20 C, no dopant-dependent charge trapping is seen, similar to that observed at higher temperatures. In the unbiased Z-process n-channels, after 1 MeV electron irradiation, considerable negative charge remains in the gate oxide.

  2. Sestrin2 protects the myocardium against radiation-induced damage

    International Nuclear Information System (INIS)

    Zeng, Yue-Can; Chi, Feng; Xing, Rui; Gao, Song; Chen, Jia-Jia; Duan, Qiong-Yu; Sun, Yu-Nan; Niu, Nan; Tang, Mei-Yue; Wu, Rong; Zeng, Jing; Wang, Hong-Mei

    2016-01-01

    The purpose of this study was to investigate the role of Sestrin2 in response to radiation-induced injury to the heart and on the cardiomyopathy development in the mouse. Mice with genetic deletion of the Sestrin2 (Sestrin2 knockout mice [Sestrin2 KO]) and treatment with irradiation (22 or 15 Gy) were used as independent approaches to determine the role of Sestrin2. Echocardiography (before and after isoproterenol challenge) and left ventricular (LV) catheterization were performed to evaluate changes in LV dimensions and function. Masson's trichrome was used to assess myocardial fibrosis. Immunohistochemistry and Western blot were used to detect the capillary density. After 22 or 15 Gy irradiation, the LV ejection fraction (EF) was impaired in wt mice at 1 week and 4 months after irradiation when compared with sham irradiation. Compared to wt mice, Sestrin2 KO mice had significant reduction in reduced LVEF at 1 week and 4 months after irradiation. A significant increase in LV end-diastolic pressure and myocardial fibrosis and a significant decrease in capillary density were observed in irradiation-wt mice, as well as in irradiation-Sestrin2 KO mice. Sestrin2 involved in the regulation of cardiomyopathy (such as myocardial fibrosis) after irradiation. Overexpression of Sestrin2 might be useful in limiting radiation-induced myocardial injury. (orig.)

  3. Sestrin2 protects the myocardium against radiation-induced damage

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Yue-Can; Chi, Feng; Xing, Rui; Gao, Song; Chen, Jia-Jia; Duan, Qiong-Yu; Sun, Yu-Nan; Niu, Nan; Tang, Mei-Yue; Wu, Rong [Shengjing Hospital of China Medical University, Department of Medical Oncology, Cancer Center, Shenyang (China); Zeng, Jing [University of Washington School of Medicine, Department of Radiation Oncology, Seattle, WA (United States); Wang, Hong-Mei [Nanfang Hospital of Southern Medical University, Department of Radiation Oncology, Guangzhou (China)

    2016-05-15

    The purpose of this study was to investigate the role of Sestrin2 in response to radiation-induced injury to the heart and on the cardiomyopathy development in the mouse. Mice with genetic deletion of the Sestrin2 (Sestrin2 knockout mice [Sestrin2 KO]) and treatment with irradiation (22 or 15 Gy) were used as independent approaches to determine the role of Sestrin2. Echocardiography (before and after isoproterenol challenge) and left ventricular (LV) catheterization were performed to evaluate changes in LV dimensions and function. Masson's trichrome was used to assess myocardial fibrosis. Immunohistochemistry and Western blot were used to detect the capillary density. After 22 or 15 Gy irradiation, the LV ejection fraction (EF) was impaired in wt mice at 1 week and 4 months after irradiation when compared with sham irradiation. Compared to wt mice, Sestrin2 KO mice had significant reduction in reduced LVEF at 1 week and 4 months after irradiation. A significant increase in LV end-diastolic pressure and myocardial fibrosis and a significant decrease in capillary density were observed in irradiation-wt mice, as well as in irradiation-Sestrin2 KO mice. Sestrin2 involved in the regulation of cardiomyopathy (such as myocardial fibrosis) after irradiation. Overexpression of Sestrin2 might be useful in limiting radiation-induced myocardial injury. (orig.)

  4. Infrared A radiation promotes survival of human melanocytes carrying ultraviolet radiation-induced DNA damage.

    Science.gov (United States)

    Kimeswenger, Susanne; Schwarz, Agatha; Födinger, Dagmar; Müller, Susanne; Pehamberger, Hubert; Schwarz, Thomas; Jantschitsch, Christian

    2016-06-01

    The link between solar radiation and melanoma is still elusive. Although infrared radiation (IR) accounts for over 50% of terrestrial solar energy, its influence on human skin is not well explored. There is increasing evidence that IR influences the expression patterns of several molecules independently of heat. A previous in vivo study revealed that pretreatment with IR might promote the development of UVR-induced non-epithelial skin cancer and possibly of melanoma in mice. To expand on this, the aim of the present study was to evaluate the impact of IR on UVR-induced apoptosis and DNA repair in normal human epidermal melanocytes. The balance between these two effects is a key factor of malignant transformation. Human melanocytes were exposed to physiologic doses of IR and UVR. Compared to cells irradiated with UVR only, simultaneous exposure to IR significantly reduced the apoptotic rate. However, IR did not influence the repair of UVR-induced DNA damage. IR partly reversed the pro-apoptotic effects of UVR via modification of the expression and activity of proteins mainly of the extrinsic apoptotic pathway. In conclusion, IR enhances the survival of melanocytes carrying UVR-induced DNA damage and thereby might contribute to melanomagenesis. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. 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

  6. Mechanisms for radiation damage in DNA. Progress report, January 1, 1980-December 31, 1980

    International Nuclear Information System (INIS)

    Sevilla, M.D.

    1980-09-01

    In this project several mechanisms are proposed for radiation damage to DNA constituents and DNA, and a series of experiments detailed utilizing electron spin resonance spectrometry to test the proposed mechanisms. Under current investigation are irradiated systems of DNA constituents which may shed light on indirect effects. In addition, studies of radiation effects on lipids have been undertaken which will shed light on the only other proposed site for cell kill, the membrane. Studies completed during the past year are: (1) π cations produced in DNA bases by attack of oxidizing radicals; (2) INDO studies of radicals produced in peptides and carboxylic acid model compounds; (3) electron reactions with carboxylic acids, ketones and aldehydes; and (4) γ-irradiation of esters and triglycerides. Progress has been made this year in a study of radicals generated in model compounds for the sugar-phosphate backbone

  7. Mechanisms for radiation damage in DNA, Progress report, November 1, 1977--October 31, 1978

    International Nuclear Information System (INIS)

    Sevilla, M.D.

    1978-06-01

    In this project we have proposed several mechanisms for radiation damage to DNA constituents and DNA, and have detailed a series of experiments utilizing electron spin resonance spectrometry to test the proposed mechanisms. In the past we have concentrated chiefly on the direct affect of radiation on DNA. We are currently investigating systems of DNA constituents and peptides which may shed light on indirect effects. Studies which we have completed during the past year are: π-cation radicals in DNA and dinucleoside phosphates, and conformational effects on the ESR Spectra of amino acids and peptides. Studies of γ-Irradiated Peptide Solutions at 77 0 K, and studies of spin transfer in γ-irradiated nucleoside--peptide solutions were also conducted

  8. Study of Engraftment of human cord blood cells to rescue the sublethal radiation damage mice

    International Nuclear Information System (INIS)

    Cao Xiangshan; Zou Zhenghui; Yu Fei; Zhang Zhilin; Lin Baojue

    1997-01-01

    To investigate alternative source of hematopoiesis stem cells to rescue the sublethal radiation damage (SRD) casualties. Human-umbilical cord blood hematopoietic cells were transplanted into SRD mice, the survival rate and the hematopoiesis reconstitution of bone marrow were assessed. The survival rate, in the mice transplanted and the untransplanted, were 90% and 10% respectively. Bone marrow and spleen of survival mice showed human leukocytic antigen CD45 + cells. Presence of multilineage engraftment, including myeloid and erythroid lineages, were found indicating that immature human cells home to the mouse bone marrow. conclusion: engraftment of umbilical cord blood cells is very useful to reconstitute hematopoiesis of SRD casualties. As cord blood has many advantages over bone marrow and peripheral blood, it is important in rescuing radiation accidental casualties

  9. Multiscale modeling of radiation damage in Fe-based alloys in the fusion environment

    International Nuclear Information System (INIS)

    Wirth, B.D.; Odette, G.R.; Marian, J.; Ventelon, L.; Young-Vandersall, J.A.; Zepeda-Ruiz, L.A.

    2004-01-01

    Ferritic alloys represent a technologically important class of candidate materials for fusion first wall and blanket structures. A detailed understanding of the mechanisms of defect accumulation and microstructure evolution, and the corresponding effects on mechanical properties is required to predict their in-service structural performance limits. The physical processes involved in radiation damage, and its effects on mechanical properties, are inherently multiscale and hierarchical, spanning length and time scales from the atomic nucleus to meters and picosecond to decades. In this paper, we present a multiscale modeling methodology to describe radiation effects within the fusion energy environment. Selected results from atomic scale investigation are presented, focusing on (i) the mechanisms of self-interstitial dislocation loop formation with Burgers vector of a in iron relative to vanadium, (ii) helium transport and (iii) the interaction between helium and small self-interstitial clusters in iron, and (iv) dislocation-helium bubble interactions in fcc aluminum

  10. Flavonoids can protect maize DNA from the induction of ultraviolet radiation damage

    International Nuclear Information System (INIS)

    Stapleton, A.E.; Walbot, V.

    1994-01-01

    Diverse flavonoid compounds are widely distributed in angiosperm families. Flavonoids absorb radiation in the ultraviolet (UV) region of the spectrum, and it has been proposed that these compounds function as UV filters. We demonstrate that the DNA in Zea mays plants that contain flavonoids (primarily anthocyanins) is protected from the induction of damage caused by UV radiation relative to the DNA in plants that are genetically deficient in these compounds. DNA damage was measured with a sensitive and simple assay using individual monoclonal antibodies, one specific for cyclobutane pyrimidine dimer damage and the other specific for pyrimidine(6,4)pyrimidone damage. (author)

  11. Radiation damage in diagnostic windows for the TFTR

    International Nuclear Information System (INIS)

    Primak, W.

    1979-01-01

    Radiation effects in diagnostic window materials are being estimated and additional experimental data on the radiation behavior are being sought. The materials considered thus far are vitreous silica, crystal quartz, and synthetic sapphire

  12. Postbuckling Investigations of Piezoelectric Microdevices Considering Damage Effects

    Science.gov (United States)

    Sun, Zhigang; Wang, Xianqiao

    2014-01-01

    Piezoelectric material has been emerging as a popular building block in MEMS devices owing to its unique mechanical and electrical material properties. However, the reliability of MEMS devices under buckling deformation environments remains elusive and needs to be further explored. Based on the Talreja's tensor valued internal state damage variables as well as the Helmhotlz free energy of piezoelectric material, a constitutive model of piezoelectric materials with damage is presented. The Kachanvo damage evolution law under in-plane compressive loads is employed. The model is applied to the specific case of the postbuckling analysis of the piezoelectric plate with damage. Then, adopting von Karman's plate theory, the nonlinear governing equations of the piezoelectric plates with initial geometric deflection including damage effects under in-plane compressive loads are established. By using the finite difference method and the Newmark scheme, the damage evolution for damage accumulation is developed and the finite difference procedure for postbuckling equilibrium path is simultaneously employed. Numerical results show the postbuckling behaviors of initial flat and deflected piezoelectric plates with damage or no damage under different sets of electrical loading conditions. The effects of applied voltage, aspect ratio of plate, thick-span ratio of plate, damage as well as initial geometric deflections on the postbuckling behaviors of the piezoelectric plate are discussed. PMID:24618774

  13. Investigation of damage in KDP using scattering techniques

    International Nuclear Information System (INIS)

    Woods, B.; Runkel, M.; Yan, M.; Staggs, M.; Zaitseva, N.; Kozlowski, M.; De Yoreo, J.

    1997-01-01

    Interest in producing high damage threshold KH 2 PO 4 (KDP) and (D x H 1-x ) 2 PO 4 (DKDP)(also called KD*P) for frequency conversion and optical switching applications is driven by the requirements of the National Ignition Facility (NIF). Presently only the best crystals meet the NIF system requirements at the third harmonic (351 nm) and only after a laser conditioning process. Neither the mechanism for damage in bulk KDP nor the mechanism for conditioning is understood. As part of a development effort to increase the damage thresholds of KDP and DKDP, we have been developing techniques to pinpoint the locations where damage will initiate in the bulk material. After we find these locations we will use other measurement techniques to determine how these locations differ from the other surrounding material and why they cause damage. This will allow crystal growers to focus their efforts to improve damage thresholds. Historically damage thresholds have increased it is believed as a consequence of increased purity of the growth solution and through the use of constant filtration during the growth process. As a result we believe that damage is caused by defects in the crystals and have conducted a series of experiments using light scatter to locate these defects and to determine when and where damage occurs. In this paper we present results which show a low correlation between light scatter from bulk defects in KDP and the initiation sites for damage. We have also studied the effects of thermal conditioning on light scatter, strain induced birefringence and damage threshold. We have seen evidence that regions of high strain also exhibit lower damage threshold than the surrounding lower strain material. When thermally conditioned, these crystals show a decrease in some of the strong linear scattering features and a decrease in the strain birefringence while the damage threshold in these regions increased to that of the surrounding bulk material

  14. Investigation of Magnetospheric Line Radiation above China

    Science.gov (United States)

    Sheng, X.; Wu, J.; Pu, X.

    2017-12-01

    Magnetospheric Line Radiation (MLR) is a kind of VLF emission that is considered by some researchers to be related with the power system on ground, and in frequency-time spectrograms of electromagnetic field, it has a line structure with large frequency bandwidth. These emission waves propagate through the magnetosphere and strongly interact with energetic electrons trapped in the earth's magnetic field. Such a wave-particle interaction amplifies the radiation and scatters energetic electrons, which may trigger new radiations. We detected 328 MLR events by analyzing the electric field data observed by DEMETER satellite in the space above China from the year of 2008 to 2010. Their characteristics and possible cause have been investigated systematically. There were more MLR events in daytime than in nighttime and more in winter than in summer. Such diurnal and seasonal differences were closely associated with whistlers and ionosphere conditions. Comparing Kp indices at the occurring time of MLR events and nationwide Kp indices through the analyzed years, we found these MLR events were not significantly dependent on geomagnetic activity. Most of events were distributed in the low latitude, while their peak intensities in frequency-time spectrograms seemed to be independent of latitude. The frequency intervals of MLR events were between 50 to 95Hz, and the frequency drifts were mostly in 0 0.4Hz/s. The above characteristics of MLR events were similar to those of Power Line Harmonic Radiation (PLHR) events observed in the space above China, therefore we inferred that these two emissions have close relation.

  15. Radiation damage studies on polystyrene-based scintillators

    International Nuclear Information System (INIS)

    Britvich, G.I.; Peresypkin, A.I.; Rykalin, V.I.

    1991-01-01

    The radiation resistance of polystyrene-based scintillators containing various scintillation dopes is reported. All samples were irradiated to 137 Cs gamma rays in air at room temperature. The examination of radiation resistance of about thirty fluorescence compounds has been made. The most radiation-hard fluores are X25, X31, 3HF and M3HF. 1 fig.; 6 tabs

  16. Caffeine potentiates or protects against radiation-induced DNA and chromosomal damage in human lymphocytes depending on temperature and concentration

    Energy Technology Data Exchange (ETDEWEB)

    Stoilov, L.M. (Department of Molecular Genetics, Institute of Genetics, Sofia (Bulgaria)); Mullenders, L.H.F.; Natarajan, A.T. (J.A. Cohen Institute, Interuniversity Research Institute for Radiopathology and Radiation Protection, Leiden (Netherlands))

    1994-12-01

    The effect of caffeine on radiation-induced chromosomal aberrations and DNA strand breaks in unstimulated human lymphocytes was investigated. When present prior to and during the radiation exposure, caffeine treatment was found to cause either potentiation or protection against induction of chromosomal aberrations depending on the concentration and temperature. When the nucleoid sedimentation technique was applied, enhancement or reduction of radiation-induced DNA strand breaks by caffeine was also found to be dependent on temperature and caffeine concentration. It is proposed that caffeine, in addition to its suspected ability to influence DNA repair, can also influence the induction of DNA damage, leading to alterations in the yield of chromosomal aberrations.

  17. Caffeine potentiates or protects against radiation-induced DNA and chromosomal damage in human lymphocytes depending on temperature and concentration

    International Nuclear Information System (INIS)

    Stoilov, L.M.; Mullenders, L.H.F.; Natarajan, A.T.

    1994-01-01

    The effect of caffeine on radiation-induced chromosomal aberrations and DNA strand breaks in unstimulated human lymphocytes was investigated. When present prior to and during the radiation exposure, caffeine treatment was found to cause either potentiation or protection against induction of chromosomal aberrations depending on the concentration and temperature. When the nucleoid sedimentation technique was applied, enhancement or reduction of radiation-induced DNA strand breaks by caffeine was also found to be dependent on temperature and caffeine concentration. It is proposed that caffeine, in addition to its suspected ability to influence DNA repair, can also influence the induction of DNA damage, leading to alterations in the yield of chromosomal aberrations

  18. Investigation of Sideband Index Response to Prototype Gear Tooth Damage

    Science.gov (United States)

    Dempsey, Paula J.

    2013-01-01

    The objective of this analysis was to evaluate the ability of gear condition indicators (CI) to detect contact fatigue damage on spiral bevel gear teeth. Tests were performed in the NASA Glenn Spiral Bevel Gear Fatigue Rig on eight prototype gear sets (pinion/gear). Damage was initiated and progressed on the gear and pinion teeth. Vibration data was measured during damage progression at varying torque values while varying damage modes to the gear teeth were observed and documented with inspection photos. Sideband indexes (SI) and root mean square (RMS) CIs were calculated from the time synchronous averaged vibration data. Results found that both CIs respond differently to varying torque levels, damage levels and damage modes

  19. Electronic excitations and their effect on the interionic forces in simulations of radiation damage in metals

    International Nuclear Information System (INIS)

    Race, C P; Mason, D R; Sutton, A P

    2009-01-01

    Using time-dependent tight-binding simulations of radiation damage cascades in a model metal we directly investigate the nature of the excitations of a system of quantum mechanical electrons in response to the motion of a set of classical ions. We furthermore investigate the effect of these excitations on the attractive electronic forces between the ions. We find that the electronic excitations are well described by a Fermi-Dirac distribution at some elevated temperature, even in the absence of the direct electron-electron interactions that would be required in order to thermalize a non-equilibrium distribution. We explain this result in terms of the spectrum of characteristic frequencies of the ionic motion. Decomposing the electronic force into four well-defined components within the basis of instantaneous electronic eigenstates, we find that the effect of accumulated excitations in weakening the interionic bonds is mostly (95%) accounted for by a thermal model for the electronic excitations. This result justifies the use of the simplifying assumption of a thermalized electron system in simulations of radiation damage with an electronic temperature dependence and in the development of temperature-dependent classical potentials.

  20. Electronic excitations and their effect on the interionic forces in simulations of radiation damage in metals.

    Science.gov (United States)

    Race, C P; Mason, D R; Sutton, A P

    2009-03-18

    Using time-dependent tight-binding simulations of radiation damage cascades in a model metal we directly investigate the nature of the excitations of a system of quantum mechanical electrons in response to the motion of a set of classical ions. We furthermore investigate the effect of these excitations on the attractive electronic forces between the ions. We find that the electronic excitations are well described by a Fermi-Dirac distribution at some elevated temperature, even in the absence of the direct electron-electron interactions that would be required in order to thermalize a non-equilibrium distribution. We explain this result in terms of the spectrum of characteristic frequencies of the ionic motion. Decomposing the electronic force into four well-defined components within the basis of instantaneous electronic eigenstates, we find that the effect of accumulated excitations in weakening the interionic bonds is mostly (95%) accounted for by a thermal model for the electronic excitations. This result justifies the use of the simplifying assumption of a thermalized electron system in simulations of radiation damage with an electronic temperature dependence and in the development of temperature-dependent classical potentials.

  1. Photoprotection beyond ultraviolet radiation--effective sun protection has to include protection against infrared A radiation-induced skin damage.

    Science.gov (United States)

    Schroeder, P; Calles, C; Benesova, T; Macaluso, F; Krutmann, J

    2010-01-01

    Solar radiation is well known to damage human skin, for example by causing premature skin ageing (i.e. photoageing). We have recently learned that this damage does not result from ultraviolet (UV) radiation alone, but also from longer wavelengths, in particular near-infrared radiation (IRA radiation, 760-1,440 nm). IRA radiation accounts for more than one third of the solar energy that reaches human skin. While infrared radiation of longer wavelengths (IRB and IRC) does not penetrate deeply into the skin, more than 65% of the shorter wavelength (IRA) reaches the dermis. IRA radiation has been demonstrated to alter the collagen equilibrium of the dermal extracellular matrix in at least two ways: (a) by leading to an increased expression of the collagen-degrading enzyme matrix metalloproteinase 1, and (b) by decreasing the de novo synthesis of the collagen itself. IRA radiation exposure therefore induces similar biological effects to UV radiation, but the underlying mechanisms are substantially different, specifically, the cellular response to IRA irradiation involves the mitochondrial electron transport chain. Effective sun protection requires specific strategies to prevent IRA radiation-induced skin damage. 2010 S. Karger AG, Basel.

  2. An investigation of the alternating fractionation formula of the Cumulative Radiation Effect

    International Nuclear Information System (INIS)

    Hamlet, R.; Kirk, J.; Perry, A.M.

    1980-01-01

    The alternating fractionation formula of the Cumulative Radiation Effect (CRE) system was investigated using the mouse intestinal crypt system as a method of assessment of the amount of radiation damage in a normal tissue. The experimental results revealed that the formula is correct in predicting an increased effect with alternating large and small sized fractions, when compared with a standard schedule where the fraction size was kept constant but achieved the same total dose. However, the results also demonstrated that the order in which the alternate fractions were administered affected the amount of radiation damage produced in the tissue. This observation is in contradiction to another prediction of the formula, that the order in which equal numbers of fractions of different magnitudes are administered, will have no effect on the biological end point. The formula, therefore, is only an approximate model of radiation damage in normal tissue and much more information is required before it can be improved upon. (author)

  3. Bruce B fuelling-with-flow operations: fuel damage investigation

    Energy Technology Data Exchange (ETDEWEB)

    Manzer, A.M. [CANTECH Associates Ltd., Burlington, Ontario (Canada); Morikawa, D. [Atomic Energy of Canada Limited, Mississauga, Ontario (Canada); Hains, A.J.; Cichowlas, W.M. [Nuclear Safety Solutions Limited, Toronto, Ontario (Canada); Roberts, J.G.; Wylie, J. [Bruce Power, Ontario (Canada)

    2005-07-01

    This paper summarizes the fuel bundle damage characterization done by Nuclear Safety Solutions Limited (NSS) and the out-reactor flow visualization tests done at Atomic Energy of Canada Limited (AECL) to reproduce the damage observed on irradiated fuel bundles. The bearing pad damage mechanism was identified and the tests showed that a minor change to the fuelling sequence would eliminate the mechanical interaction. The change was implemented in January 2005. Since then, the bearing pad damage appears to have been greatly reduced based on the small number of discharged bundles inspected to date. (author)

  4. Bruce B fuelling-with-flow operations: fuel damage investigation

    International Nuclear Information System (INIS)

    Manzer, A.M.; Morikawa, D.; Hains, A.J.; Cichowlas, W.M.; Roberts, J.G.; Wylie, J.

    2005-01-01

    This paper summarizes the fuel bundle damage characterization done by Nuclear Safety Solutions Limited (NSS) and the out-reactor flow visualization tests done at Atomic Energy of Canada Limited (AECL) to reproduce the damage observed on irradiated fuel bundles. The bearing pad damage mechanism was identified and the tests showed that a minor change to the fuelling sequence would eliminate the mechanical interaction. The change was implemented in January 2005. Since then, the bearing pad damage appears to have been greatly reduced based on the small number of discharged bundles inspected to date. (author)

  5. Cytogenetic techniques as biological indicator and dosimeter of radiation damage

    International Nuclear Information System (INIS)

    Hadjidekova, V.; Hristova, R.

    2006-01-01

    Full text: The cytogenetic methods are established techniques for bio monitoring and bio dosimetry of professionally and accidentally exposed to ionizing radiation subjects. They are applied to continue the evaluation of the physical dosimetry and to consider the individual radiosensitivity. The results of cytogenetic monitoring and dosimetry of radiation exposed subjects carried out during the last 5 years in laboratory of Radiation Genetics, NCRRP is reported. Laboratory of Radiation genetics performs cytogenetic monitoring of low dose radiation professionally or medically exposed subjects: workers in Kozloduy NPP, radioactive waste repository workers, X-rays diagnostically exposed patients, and radiotherapy exposed as well. Three cytogenetic indicators are applied as the most sensitive indicators for human radiation exposure: analysis of micronuclei (MN), chromosomal aberrations (CA) and stable translocations (FISH). The optimized methodology for application of different cytogenetic techniques for radiation estimation is discussed

  6. Radiation and transposon-induced genetic damage in Drosophila melanogaster

    International Nuclear Information System (INIS)

    Balter, H.; Griffith, C.S.; American Museum of Natural History, New York; Margulies, L.

    1992-01-01

    The interaction of X-ray-induced and transposon-induced damage was investigated in P-M hybrid dysgenesis in Drosophila melanogaster. X-ray dose-response of 330-1320 rad was monitored for sterility, fecundicity and partial X/Y chromosome loss among F 2 progeny derived from dysgenic cross of M strain females xP strain males (cross A) and its reciprocal (cross B), using a weaker and the standard Harwich P strain subline. The synergistic effect of P element activity and X-rays on sterility was observed only in cross A hybrids and the dose-response was nonlinear in hybrids derived from the strong standard reference Harwich subline, H W . This finding suggests that lesions induced by both mutator systems which produce the synergistic effects are 2-break events. Effect of increasing dose on the decline of fecundicity was synergistic, but linear, in hybrids of either subline. There was no interaction evident and thus no synergism in X/Y nondisjunction and partial Y chromosome loss measured by the loss of the B s marker alone or together with the y + marker. Interaction was detected in the loss of the y + marker alone from the X and Y chromosomes. The possible three-way interaction of X-rays (660 rad), post-replication repair deficiency and P elements mobility was assessed by measuring transmission distortion in dysgenic males derived from the Π 2 P strain. (author). 38 refs.; 5 tabs

  7. Quantification of complex DNA damage by ionising radiation. An experimental and theoretical approach

    International Nuclear Information System (INIS)

    Fulford, J.

    2000-05-01

    Ionising radiation potentially produces a broad spectrum of damage in DNA including single and double strand breaks (ssb and dsb) and base damages. It has been hypothesised that sites of complex damage within cellular DNA have particular biological significance due to an associated decreased efficiency in repair. The aim of this study is to gain further understanding of the formation of complex DNA damage. Irradiations of plasmid DNA illustrate that an increase in ionising density of the radiation results in a decrease in ssb yields/Gy but an increase in dsb per ssb, indicative of an increase in the number of complex damage sites per simple isolated damage site. As the mechanism for damage formation shifts from purely indirect at low scavenging capacities to a significant proportion of direct at higher scavenging capacities the proportion of complex damage increases. Comparisons with the yields of ssb and dsb simulated by Monte-Carlo calculations for Al K USX and α-particles also indicate this correspondence. The ionisation density of low energy, secondary electrons produced by photons was assessed experimentally from the dependence of the yield of OH radicals escaping intra-track recombination on photon energy. As energy decreases the OH radical yield initially decreases reflecting an increased ionisation density. However, with further decrease in photon energy the yield of OH radicals increases in line with theoretical calculations. Base damage yields were determined for low and high ionising density radiation over a range of scavenging capacities. As scavenging capacity increases the base damage: ssb ratios increases implying a contribution from electrons to base damage. It is proposed that base damage contributes to DNA damage complexity. Complex damage analysis reveals that at cell mimetic scavenging capacities, 23% and 72% of ssb have an additional spatially close damage site following γ-ray and α-particle irradiation respectively. (author)

  8. Radiation-induced DNA damage and cellular lethality

    International Nuclear Information System (INIS)

    Sakai, K.; Okada, S.

    1984-01-01

    Radiation-induced DNA scissions and their repair were investigated in mammalian cells using an alkaline separation method. DNA breaks in mouse L5178Y cells and Chinese hamster V79 cells were grouped into three in terms of their repair profile; fast-reparable breaks (FRBs; T1/2 = 5 min), slow-reparable breaks (SRBs; T1/2 = 70 min) and non-reparable breaks (NRBs). The three types of DNA lesions were studied under conditions where cellular radiosensitivity was modified. The authors obtained the following results: 1. Cell cycle fluctuation: L5178Y showed maximum sensitivity at M and G/sub 1/-S boundary, and minimum sensitivity at G/sub 1/ and late S. Cycle dependency was not found for FRBs or SRBs, but NRBs showed bimodal fluctuation with peaks at M and G/sub 1/-S, and with bottoms at G/sub 1/ and late S. 2. Different sensitivity of L5178Y and V79: L5178Y cells were more sensitive to X-rays (D/sub ο/ = 0.9 Gy) than V79 (D/sub ο/ = 1.8 Gy). The amount of FRBs or SRBs was identical in the two cell lines. However, the amount of NRBs in L5178Y was greater than that in V79. 3. Split dose irradiation: The time interval between two doses resulted in a gradual decrease of NRBs. The time course of the decrease was similar to the split dose recovery in terms of cell death. The parallel relationship between NRBs and cell killing implies that NRBs could play an important role in radiation-induced cell death

  9. The interactions of radiation damage with grain boundaries

    International Nuclear Information System (INIS)

    King, A.H.

    1979-01-01

    This thesis reports a theoretical and experimental study of the fundamental effects giving rise to zones adjacent to grain boundaries which are denuded of irradiation-induced damage. The results, however, have significance in the wider field of point-defect absorption (and emission) by grain boundaries. Particular emphasis has been laid upon correlating the point-defect sink behaviour of grain boundaries with their structures and to this end, grain boundaries with periodically repeating structures have been chosen for study. The hypotheses that point-defect absorption is achieved by the climb of grain boundary dislocation spirals, loops and structural arrays have been investigated and firm evidence has been found to support the two latter mechanisms in specific cases. Loops, in particular, have been found to grow only on coherent twin boundary planes. Chapter two of the thesis investigates the crystallographic nature of the possible reactions of point-defects with periodic boundaries and demonstrates that effects such as grain boundary migration and grain translations may be associated with point-defect absorption. Chapter three presents a theoretical study of the effects of elastic interactions between point-defects and grain boundary dislocations and gives predictions of sink strength and bias of a grain boundary as a function of its structure. Chapter four consists of experimental examples of grain boundaries observed during and after irradiation. Chapter five discusses the results of chapters two, three and four considering their implications for the various hypotheses and presents the conclusions of the thesis and some suggestions for further work. (author)

  10. Non-Destructive Detection and Separation of Radiation Damaged Cells in Miniaturized, Inexpensive Device, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — There is a clear and well-identified need for rapid, efficient, non-destructive detection and isolation of radiation damaged cells. Available commercial technologies...

  11. 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

  12. Account of the effect of nuclear collision cascades in model of radiation damage of RPV steels

    International Nuclear Information System (INIS)

    Kevorkyan, Yu.R.; Nikolaev, Yu.A.

    1997-01-01

    A kinetic model is proposed for describing the effect of collision cascades in model of radiation damage of reactor pressure vessel steels. This is a closed system of equations which can be solved only by numerical methods in general case

  13. The use of the SRIM code for calculation of radiation damage induced by neutrons

    Science.gov (United States)

    Mohammadi, A.; Hamidi, S.; Asadabad, Mohsen Asadi

    2017-12-01

    Materials subjected to neutron irradiation will being evolve to structural changes by the displacement cascades initiated by nuclear reaction. This study discusses a methodology to compute primary knock-on atoms or PKAs information that lead to radiation damage. A program AMTRACK has been developed for assessing of the PKAs information. This software determines the specifications of recoil atoms (using PTRAC card of MCNPX code) and also the kinematics of interactions. The deterministic method was used for verification of the results of (MCNPX+AMTRACK). The SRIM (formely TRIM) code is capable to compute neutron radiation damage. The PKAs information was extracted by AMTRACK program, which can be used as an input of SRIM codes for systematic analysis of primary radiation damage. Then the Bushehr Nuclear Power Plant (BNPP) radiation damage on reactor pressure vessel is calculated.

  14. Radiation damages and electro-conductive characteristics of Neutron-Transmutation-Doped GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Kuriyama, Kazuo; Sato, Masataka; Sakai, Kiyohiro [Hosei Univ., Koganei, Tokyo (Japan). Coll. of Engineering; Okada, Moritami

    1996-04-01

    Neutron Transmutation Doping (NTD) method made it possible to do homogeneous doping of impurities and to easily control the doping level. Thus, the method has been put into practice for some materials such as silicon. Here, the annealing behavior of anti-site defects generated in neutron-irradiated GaAs was studied. Electric activations of NTD-impurities were started around 550degC in P1 and P2 radiation fields, which were coincident with the beginning of extinction of electron trapping which was caused by anti-site defects due to fast neutron radiation. The electric resistivities of GaAs in neutron radiation fields; P1, P2 and P3 changed depending with the annealing temperature. The electric resistivities of GaAs in P1 and P2 fields indicate the presence of hopping conduction through radiation damages. The resistance of GaAs irradiated in P1 was smaller by nearly 2 orders than that of the untreated control. Further, the electric activation process for NTD-impurities was investigated using ESR and Raman spectroscopy. (M.N.)

  15. Radiation damage to tetramethylsilane and tetramethylgermanium ionization chambers

    International Nuclear Information System (INIS)

    Hoshi, Y.; Higuchi, M.; Oyama, K.

    1994-01-01

    Two detector media suitable for a warm liquid, ionization chamber filled with tetramethylsilane (TMS) and tetramethylgermanium (TMG) were exposed to γ radiation form a 60 Co source up to dose 579 Gray and 902 Gray, respectively. The electron lifetimes and the free ion yields were measured as a function of accumulated radiation dose. A similar behavior of the electron lifetimes and the free ion yields with increasing radiation does was observed between the TMS and TMG ionization chambers

  16. Pudendal Nerve and Internal Pudendal Artery Damage May Contribute to Radiation-Induced Erectile Dysfunction

    Energy Technology Data Exchange (ETDEWEB)

    Nolan, Michael W., E-mail: mwnolan@ncsu.edu [Department of Clinical Sciences, and Center for Comparative Medicine and Translational Research, North Carolina State University, Raleigh, North Carolina (United States); Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado (United States); Marolf, Angela J. [Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado (United States); Ehrhart, E.J. [Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado (United States); Rao, Sangeeta [Department of Clinical Sciences, Colorado State University, Fort Collins, Colorado (United States); Kraft, Susan L. [Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado (United States); Engel, Stephanie [Department of Clinical Sciences, Colorado State University, Fort Collins, Colorado (United States); Yoshikawa, Hiroto; Golden, Anne E. [Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado (United States); Wasserman, Todd H. [Department of Radiation Oncology, Washington University, St. Louis, Missouri (United States); LaRue, Susan M. [Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado (United States)

    2015-03-15

    Purpose/Objectives: Erectile dysfunction is common after radiation therapy for prostate cancer; yet, the etiopathology of radiation-induced erectile dysfunction (RI-ED) remains poorly understood. A novel animal model was developed to study RI-ED, wherein stereotactic body radiation therapy (SBRT) was used to irradiate the prostate, neurovascular bundles (NVB), and penile bulb (PB) of dogs. The purpose was to describe vascular and neurogenic injuries after the irradiation of only the NVB or the PB, and after irradiation of all 3 sites (prostate, NVB, and PB) with varying doses of radiation. Methods and Materials: Dogs were treated with 50, 40, or 30 Gy to the prostate, NVB, and PB, or 50 Gy to either the NVB or the PB, by 5-fraction SBRT. Electrophysiologic studies of the pudendal nerve and bulbospongiosus muscles and ultrasound studies of pelvic perfusion were performed before and after SBRT. The results of these bioassays were correlated with histopathologic changes. Results: SBRT caused slowing of the systolic rise time, which corresponded to decreased arterial patency. Alterations in the response of the internal pudendal artery to vasoactive drugs were observed, wherein SBRT caused a paradoxical response to papaverine, slowing the systolic rise time after 40 and 50 Gy; these changes appeared to have some dose dependency. The neurofilament content of penile nerves was also decreased at high doses and was more profound when the PB was irradiated than when the NVB was irradiated. These findings are coincident with slowing of motor nerve conduction velocities in the pudendal nerve after SBRT. Conclusions: This is the first report in which prostatic irradiation was shown to cause morphologic arterial damage that was coincident with altered internal pudendal arterial tone, and in which decreased motor function in the pudendal nerve was attributed to axonal degeneration and loss. Further investigation of the role played by damage to these structures in RI-ED is

  17. Involvement of inducible nitric oxide synthase in radiation-induced vascular endothelial damage

    International Nuclear Information System (INIS)

    Hong, Chang-Won; Lee, Joon-Ho; Kim, Suwan; Noh, Jae Myoung; Kim, Young-Mee; Pyo, Hongryull; Lee, Sunyoung

    2013-01-01

    The use of radiation therapy has been linked to an increased risk of cardiovascular disease. To understand the mechanisms underlying radiation-induced vascular dysfunction, we employed two models. First, we examined the effect of X-ray irradiation on vasodilation in rabbit carotid arteries. Carotid arterial rings were irradiated with 8 or 16 Gy using in vivo and ex vivo methods. We measured the effect of acetylcholine-induced relaxation after phenylephrine-induced contraction on the rings. In irradiated carotid arteries, vasodilation was significantly attenuated by both irradiation methods. The relaxation response was completely blocked by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a potent inhibitor of soluble guanylate cyclase. Residual relaxation persisted after treatment with L-N ω -nitroarginine (L-NA), a non-specific inhibitor of nitric oxide synthase (NOS), but disappeared following the addition of aminoguanidine (AG), a selective inhibitor of inducible NOS (iNOS). The relaxation response was also affected by tetraethylammonium, an inhibitor of endothelium-derived hyperpolarizing factor activity. In the second model, we investigated the biochemical events of nitrosative stress in human umbilical-vein endothelial cells (HUVECs). We measured iNOS and nitrotyrosine expression in HUVECs exposed to a dose of 4 Gy. The expression of iNOS and nitrotyrosine was greater in irradiated HUVECs than in untreated controls. Pretreatment with AG, L-N 6 -(1-iminoethyl) lysine hydrochloride (a selective inhibitor of iNOS), and L-NA attenuated nitrosative stress. While a selective target of radiation-induced vascular endothelial damage was not definitely determined, these results suggest that NO generated from iNOS could contribute to vasorelaxation. These studies highlight a potential role of iNOS inhibitors in ameliorating radiation-induced vascular endothelial damage. (author)

  18. Lovastatin attenuates ionizing radiation-induced normal tissue damage in vivo

    International Nuclear Information System (INIS)

    Ostrau, Christian; Huelsenbeck, Johannes; Herzog, Melanie; Schad, Arno; Torzewski, Michael; Lackner, Karl J.; Fritz, Gerhard

    2009-01-01

    Background and purpose: HMG-CoA-reductase inhibitors (statins) are widely used lipid-lowering drugs. Moreover, they have pleiotropic effects on cellular stress responses, proliferation and apoptosis in vitro. Here, we investigated whether lovastatin attenuates acute and subchronic ionizing radiation-induced normal tissue toxicity in vivo. Materials and methods: Four hours to 24 h after total body irradiation (6 Gy) of Balb/c mice, acute pro-inflammatory and pro-fibrotic responses were analyzed. To comprise subchronic radiation toxicity, mice were irradiated twice with 2.5 Gy and analyses were performed 3 weeks after the first radiation treatment. Molecular markers of inflammation and fibrosis as well as organ toxicities were measured. Results: Lovastatin attenuated IR-induced activation of NF-κB, mRNA expression of cell adhesion molecules and mRNA expression of pro-inflammatory and pro-fibrotic marker genes (i.e. TNFα, IL-6, TGFβ, CTGF, and type I and type III collagen) in a tissue- and time-dependent manner. γH2AX phosphorylation stimulated by IR was not affected by lovastatin, indicating that the statin has no major impact on the induction of DNA damage in vivo. Radiation-induced thrombopenia was significantly alleviated by lovastatin. Conclusions: Lovastatin inhibits both acute and subchronic IR-induced pro-inflammatory and pro-fibrotic responses and cell death in normal tissue in vivo. Therefore, lovastatin might be useful for selectively attenuating acute and subchronic normal tissue damage caused by radiotherapy.

  19. Impact of oxygen concentration on yields of DNA damages caused by ionizing radiation

    Czech Academy of Sciences Publication Activity Database

    Štěpán, Václav; Davídková, Marie

    2008-01-01

    Roč. 101, 012015 (2008), s. 1-4 ISSN 1742-6588. [Radiation Damage in Biomolecular Systems, RADAM'07. Dublin, 19.06.2007-22.06.2007] R&D Projects: GA ČR(CZ) GD202/05/H031; GA ČR GA202/05/2728 Institutional research plan: CEZ:AV0Z10480505 Keywords : radiation damage to DNA * oxygen concentration * theoretical modeling Subject RIV: BO - Biophysics

  20. The Future of the South Atlantic Anomaly and Implications for Radiation Damage in Space

    Science.gov (United States)

    Heirtzler, J. R.; Smith, David E. (Technical Monitor)

    2000-01-01

    South Atlantic Anomaly of the geomagnetic field plays a dominant role in where radiation damage occurs in near Earth orbits. The historic and recent variations of the geomagnetic field in the South Atlantic are used to estimate the extent of the South Atlantic Anomaly until the year 2000. This projection indicates that radiation damage to spacecraft and humans in space will greatly increase and cover a much larger geographic area than present.