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Sample records for irradiated melanosome particles

  1. Melanosomes are a primary target of Q-switched ruby laser irradiation in guinea pig skin

    Energy Technology Data Exchange (ETDEWEB)

    Polla, L.L.; Margolis, R.J.; Dover, J.S.; Whitaker, D.; Murphy, G.F.; Jacques, S.L.; Anderson, R.R.

    1987-09-01

    The specific targeting of melanosomes may allow for laser therapy of pigmented cutaneous lesions. The mechanism of selective destruction of pigmented cells by various lasers, however, has not been fully clarified. Black, brown, and albino guinea pigs were exposed to optical pulses at various radiant exposure doses from a Q-switched, 40 nsec, 694 nm ruby laser. Biopsies were analyzed by light and electron microscopy (EM). Albino animals failed to develop clinical or microscopic evidence of cutaneous injury after irradiation. In both black and brown animals, the clinical threshold for gross change was 0.4 J/cm2, which produced an ash-white spot. By light microscopy, alterations appeared at 0.3 J/cm2 and included separation at the dermoepidermal junction, and the formation of vacuolated epidermal cells with a peripheral cytoplasmic condensation of pigment. By EM, enlarged melanosomes with a central lucent zone were observed within affected epidermal cells at 0.3 J/cm2. At 0.8 and 1.2 J/cm2, individual melanosomes were more intensely damaged and disruption of melanosomes deep in the hair papillae was observed. Dermal-epidermal blisters were formed precisely at the lamina lucida, leaving basal cell membranes and hemidesmosomes intact. Possible mechanisms for melanosomal injury are discussed. These observations show that the effects of the Q-switched ruby laser are melanin-specific and melanin-dependent, and may be useful in the selective destruction of pigmented as well as superficial cutaneous lesions.

  2. Redistribution of melanosomal complexes within keratinocytes following UV-A irradiation

    International Nuclear Information System (INIS)

    Lavker, R.M.; Kaidbey, K.H.

    1982-01-01

    In contrast to other ultraviolet (UV) wavelengths, UV-A can induce long-term or 'true' pigmentation rapidly with little or no latency. The response cannot be clearly separated from immediate pigment darkening and is too rapid in onset to be explained by neomelanogenesis. In order to investigate possible mechanisms for this phenomenon, UV-irradiated skin was examined microscopically and ultrastructurally 18 h postirradiation. Specimens from skin sites tanned by exposure to melanogenic doses of UV-A showed a paradoxical reduction in the degree of basal melanization by light microscopy compared to unirradiated skin. Ultrastructurally, there was migration and dispersion of packaged melanosomes within keratinocytes from their normal, aggregated location around the nucleus towards the periphery of the cell. These changes were not observed in specimens exposed to melanogenic doses of UV-B. We propose that UV-A wavelengths can selectively cause redistribution of melanin-laden organelles within human keratinocytes in vivo and that this phenomenon accounts for the visually observed hyperpigmentation that develops soon after single exposures to these wavelengths. Dispersion of melanosomal complexes may be another mechanism by which UV-radiation (UVR) can induce tanning in human skin. (orig.)

  3. Redistribution of melanosomal complexes within keratinocytes following UV-A irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lavker, R.M.; Kaidbey, K.H.

    1982-03-01

    In contrast to other ultraviolet (UV) wavelengths, UV-A can induce long-term or 'true' pigmentation rapidly with little or no latency. The response cannot be clearly separated from immediate pigment darkening and is too rapid in onset to be explained by neomelanogenesis. In order to investigate possible mechanisms for this phenomenon, UV-irradiated skin was examined microscopically and ultrastructurally 18 h postirradiation. Specimens from skin sites tanned by exposure to melanogenic doses of UV-A showed a paradoxical reduction in the degree of basal melanization by light microscopy compared to unirradiated skin. Ultrastructurally, there was migration and dispersion of packaged melanosomes within keratinocytes from their normal, aggregated location around the nucleus towards the periphery of the cell. These changes were not observed in specimens exposed to melanogenic doses of UV-B. We propose that UV-A wavelengths can selectively cause redistribution of melanin-laden organelles within human keratinocytes in vivo and that this phenomenon accounts for the visually observed hyperpigmentation that develops soon after single exposures to these wavelengths. Dispersion of melanosomal complexes may be another mechanism by which UV-radiation (UVR) can induce tanning in human skin.

  4. Irradiation behaviors of coated fuel particles, (3)

    International Nuclear Information System (INIS)

    Fukuda, Kousaku; Kashimura, Satoru; Iwamoto, Kazumi; Ikawa, Katsuichi

    1980-07-01

    This report is concerning to the irradiation experiments of the coated fuel particles, which were performed by 72F-6A and 72F-7A capsules in JMTR. The coated particles referred to the preliminary design of VHTR were prepared for the experiments in 1972 and 1973. 72F-6A capsule was irradiated at G-10 hole of JMTR fuel zone for 2 reactor cycles, and 72F-7A capsule had been planned to be irradiated at the same irradiation hole before 72F-6A. However, due to slight leak of the gaseous fission products into the vacuum system controlling irradiation temperature, irradiation of 72F-7A capsule was ceased after 85 hrs since the beginning. In the post irradiation examination, inspection to surface appearance, ceramography, X-ray microradiography and acid leaching for the irradiated particle samples were made, and crushing strength of the two particle samples was measured. (author)

  5. Melanosomal dynamics assessed with a live-cell fluorescent melanosomal marker.

    Directory of Open Access Journals (Sweden)

    Jan M Bruder

    Full Text Available Melanocytes present in skin and other organs synthesize and store melanin pigment within membrane-delimited organelles called melanosomes. Exposure of human skin to ultraviolet radiation (UV stimulates melanin production in melanosomes, followed by transfer of melanosomes from melanocytes to neighboring keratinocytes. Melanosomal function is critical for protecting skin against UV radiation, but the mechanisms underlying melanosomal movement and transfer are not well understood. Here we report a novel fluorescent melanosomal marker, which we used to measure real-time melanosomal dynamics in live human epidermal melanocytes (HEMs and transfer in melanocyte-keratinocyte co-cultures. A fluorescent fusion protein of Ocular Albinism 1 (OA1 localized to melanosomes in both B16-F1 cells and HEMs, and its expression did not significantly alter melanosomal distribution. Live-cell tracking of OA1-GFP-tagged melanosomes revealed a bimodal kinetic profile, with melanosomes exhibiting combinations of slow and fast movement. We also found that exposure to UV radiation increased the fraction of melanosomes exhibiting fast versus slow movement. In addition, using OA1-GFP in live co-cultures, we monitored melanosomal transfer using time-lapse microscopy. These results highlight OA1-GFP as a specific and effective melanosomal marker for live-cell studies, reveal new aspects of melanosomal dynamics and transfer, and are relevant to understanding the skin's physiological response to UV radiation.

  6. Irradiation behaviors of coated fuel particles, (4)

    International Nuclear Information System (INIS)

    Fukuda, Kousaku; Kashimura, Satoru; Ogawa, Toru; Ikawa, Katsuichi; Iwamoto, Kazumi; Ishimoto, Kiyoshi

    1981-09-01

    Loose coated fuel particles prepared in confirmity to a preliminary design for the multi-purpose VHTR in fiscal 1972 - 1974 were irradiated by 73F - 12A capsule in JMTR. Main purpose for this irradiation experiment was to examine irradiation stability of the candidate TRISO coated fuel particles for the VHTR. Also the coated particles possessing low-density kernel (90%TD), highly anisotropic OLTI-PyC and ZrC coating layer were loaded with the candidate particles in this capsule. The coated particles were irradiated up to 1.5 x 10 21 n/cm 2 of fast neutron fluence (E > 0.18 MeV) and 3.2% FIMA of burnup. In the post irradiation examination it was observed that among three kinds of TRISO particles exposed to irradiation corresponding to the normal operating condition of the VHTR ones possessing poor characteristics of the coating layers did not show a good stability. The particles irradiated under abnormally high temperature condition (> 1800 0 C) revealed 6.7% of max. EOL failure fraction (95% confidence limit). Most of these particles were failed by the ameoba effect. Furthermore, among four kinds of the TRISO particles exposed to irradiation corresponding to the transient condition of the VHTR (--1500 0 C) the two showed a good stability, while the particles possessing highly anisotropic OLTI-PyC or poorly characteristic coating layers were not so good. (author)

  7. Modeling of coated fuel particles irradiation behavior

    International Nuclear Information System (INIS)

    Liang Tongxiang; Phelip, M.

    2006-01-01

    In this report, PANAMA code was used to estimate the CP performance under normal and accident condition. Under the normal irradiation test (1000 degree C 625 efpd, 10% FIMA), for intact CP fuel, failure fraction is in the level of 10 -7 . As-fabricated SiC failed particles results in the through coatings failed particles much earlier than the intact particles does, OPyC layer does not fail immediately after irradiation starts. The significant failures start at beyond the burnup of about 7% FIMA. Under the accident condition, the calculated results showed that when the heating temperature is much higher than 1850 degree C, the failure fraction of coated particle can reach the level of 1 percent. The CP fuel fails significantly if it has a buffer layer thinner than 65 urn, SiC layer thinner than 30 μm. High burnup CP need to develop small size kernel, thick buffer layer and thick SiC layer. (authors)

  8. Irradiation Testing of TRISO-Coated Particle Fuel in Korea

    International Nuclear Information System (INIS)

    Kim, Bong Goo; Yeo, Sunghwan; Jeong, Kyung-Chai; Eom, Sung-Ho; Kim, Yeon-Ku; Kim, Woong Ki; Lee, Young Woo; Cho, Moon Sung; Kim, Yong Wan

    2014-01-01

    In Korea, coated particle fuel is being developed to support development of a VHTR. At the end of March 2014, the first irradiation test in HANARO at KAERI to demonstrate and qualify TRISO-coated particle fuel for use in a VHTR was terminated. This experiment was conducted in an inert gas atmosphere without on-line temperature monitoring and control, or on-line fission product monitoring of the sweep gas. The irradiation device contained two test rods, one has nine fuel compacts and the other five compacts and eight graphite specimens. Each compact contains about 260 TRISO-coated particles. The duration of irradiation testing at HANARO was about 135 full power days from last August 2013. The maximum average power per particle was about 165 mW/particle. The calculated peak burnup of the TRISO-coated fuel was a little less than 4 atom percent. Post-irradiation examination is being carried out at KAERI’s Irradiated Material Examination Facility beginning in September of 2014. This paper describes characteristics of coated particle fuel, the design of the test rod and irradiation device for this coated particle fuel, and discusses the technical results of irradiation testing at HANARO. (author)

  9. mc1r Pathway regulation of zebrafish melanosome dispersion

    DEFF Research Database (Denmark)

    Richardson, Jennifer; Lundegaard, Pia Rengtved; Reynolds, Natalie L

    2008-01-01

    Zebrafish rapidly alter their pigmentation in response to environmental changes. For black melanocytes, this change is due to aggregation or dispersion of melanin in the cell. Dispersion and aggregation are controlled by intracellular cyclic adenosine monophosphate (cAMP) levels, which increase...... in mammals, and melanosome dispersal in cold-blood vertebrates, the pathway components are highly conserved. However, it has only been assumed that mc1r mediates melanosome dispersal in fish. Here, using morpholino oligonucleotides designed to knockdown mc1r expression, we find that mc1r morphants are unable...... to disperse melanosomes when grown in dark conditions. We also use chemical modifiers of the cAMP pathway, and find an unexpected response to the specific phosphodiesterase 4 (PDE4) inhibitor, rolipram, in melanosome dispersal. When treated with the drug, melanosomes fail to fully disperse in dark conditions...

  10. Single particle irradiation effect of digital signal processor

    International Nuclear Information System (INIS)

    Fan Si'an; Chen Kenan

    2010-01-01

    The single particle irradiation effect of high energy neutron on digital signal processor TMS320P25 in dynamic working condition has been studied. The influence of the single particle on the device has been explored through the acquired waveform and working current of TMS320P25. Analysis results, test data and test methods have also been presented. (authors)

  11. Nanoparticle production by UV irradiation of combustion generated soot particles

    International Nuclear Information System (INIS)

    Stipe, Christopher B.; Choi, Jong Hyun; Lucas, Donald; Koshland, Catherine P.; Sawyer, Robert F.

    2004-01-01

    Laser ablation of surfaces normally produce high temperature plasmas that are difficult to control. By irradiating small particles in the gas phase, we can better control the size and concentration of the resulting particles when different materials are photofragmented. Here, we irradiate soot with 193 nm light from an ArF excimer laser. Irradiating the original agglomerated particles at fluences ranging from 0.07 to 0.26 J/cm 2 with repetition rates of 20 and 100 Hz produces a large number of small, unagglomerated particles, and a smaller number of spherical agglomerated particles. Mean particle diameters from 20 to 50 nm are produced from soot originally having a mean electric mobility diameter of 265nm. We use a non-dimensional parameter, called the photon/atom ratio (PAR), to aid in understanding the photofragmentation process. This parameter is the ratio of the number of photons striking the soot particles to the number of the carbon atoms contained in the soot particles, and is a better metric than the laser fluence for analyzing laser-particle interactions. These results suggest that UV photofragmentation can be effective in controlling particle size and morphology, and can be a useful diagnostic for studying elements of the laser ablation process

  12. Irradiation testing of coated particle fuel at Hanaro

    International Nuclear Information System (INIS)

    Goo Kim, Bong; Sung Cho, Moo; Kim, Yong Wan

    2014-01-01

    TRISO-coated particle fuel is developing to support development of VHTR in Korea. From August 2013, the first irradiation testing of coated particle fuel was begun to demonstrate and qualify TRISO fuel for use in VHTR in the HANARO at KAERI. This experiment is currently undergoing under the atmosphere of a mixed inert gas without on-line temperature monitoring and control combined with on-line fission product monitoring of the sweep gas. The irradiation device contains two test rods, one contains nine fuel compacts and the other five compacts and eight graphite specimens. Each compact has 263 coated particles. After a peak burn-up of about 4 at% and a peak fast neutron fluence of about 1.7 x 10 21 n/cm 2 , PIE will be carried out at KAERI's Irradiated Material Examination Facility. This paper is described characteristics of coated particle fuel, the design of test rod and irradiation device for coated particle fuel, discusses the technical results for irradiation testing at HANARO. (authors)

  13. Irradiation of single cells with individual high-LET particles

    International Nuclear Information System (INIS)

    Nelson, J.M.; Braby, L.A.

    1993-01-01

    The dose-limiting normal tissue of concern when irradiating head and neck lesions is often the vascular endothelium within the treatment field. Consequently, the response of capillary endothelial cells exposed to moderate doses of high LET particles is essential for establishing exposure limits for neutron-capture therapy. In an effort to characterize the high-LET radiation biology of cultured endothelial cells, the authors are attempting to measure cellular response to single particles. The single-particle irradiation apparatus, described below, allows them to expose individual cells to known numbers of high-LET particles and follow these cells for extended periods, in order to assess the impact of individual particles on cell growth kinetics. Preliminary cell irradiation experiments have revealed complications related to the smooth and efficient operation of the equipment; these are being resolved. Therefore, the following paragraphs deal primarily with the manner by which high LET particles deposit energy, the requirements for single-cell irradiation, construction and assembly of such apparatus, and testing of experimental procedures, rather than with the radiation biology of endothelial cells

  14. Effects of heavy particle irradiation on central nervous system

    International Nuclear Information System (INIS)

    Nojima, Kumie; Nakadai, Taeko; Khono, Yukio

    2006-01-01

    Effects of low dose heavy particle radiation to central nervous system were studied using human embryonal carcinoma (Ntera2=NT2) and Human neuroblastoma cell (NB1). They exposed to heavy ions and X ray 80% confluent cells in culture bottles. The cells were different type about growth and differentiation in the neuron. The apoptosis profile was measured by AnnexinV-EGFP, PI stained and fluorescence-activated cell sorter (FACS). Memory and learning function of adult mice were studied using water maze test after carbon- or iron-ion irradiation. Memory functions were rapidly decreased after irradiation both ions. Iron -ion group were recovered 20 weeks after irradiation C-ion group were recovered 25 weeks after irradiation. Tier memory were still keep at over 100 weeks after irradiation. (author)

  15. Microscopic analysis of irradiated AGR-1 coated particle fuel compacts

    Energy Technology Data Exchange (ETDEWEB)

    Ploger, Scott A., E-mail: scott.ploger@inl.gov [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3855 (United States); Demkowicz, Paul A. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3855 (United States); Hunn, John D.; Kehn, Jay S. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6093 (United States)

    2014-05-01

    The AGR-1 experiment involved irradiation of 72 TRISO-coated particle fuel compacts to a peak compact-average burnup of 19.5% FIMA with no in-pile failures observed out of 3 × 10{sup 5} total particles. Irradiated AGR-1 fuel compacts have been cross-sectioned and analyzed with optical microscopy to characterize kernel, buffer, and coating behavior. Six compacts have been examined, spanning a range of irradiation conditions (burnup, fast fluence, and irradiation temperature) and including all four TRISO coating variations irradiated in the AGR-1 experiment. The cylindrical specimens were sectioned both transversely and longitudinally, then polished to expose from 36 to 79 individual particles near midplane on each mount. The analysis focused primarily on kernel swelling and porosity, buffer densification and fracturing, buffer–IPyC debonding, and fractures in the IPyC and SiC layers. Characteristic morphologies have been identified, 981 particles have been classified, and spatial distributions of particle types have been mapped. No significant spatial patterns were discovered in these cross sections. However, some trends were found between morphological types and certain behavioral aspects. Buffer fractures were found in 23% of the particles, and these fractures often resulted in unconstrained kernel protrusion into the open cavities. Fractured buffers and buffers that stayed bonded to IPyC layers appear related to larger pore size in kernels. Buffer–IPyC interface integrity evidently factored into initiation of rare IPyC fractures. Fractures through part of the SiC layer were found in only four classified particles, all in conjunction with IPyC–SiC debonding. Compiled results suggest that the deliberate coating fabrication variations influenced the frequencies of IPyC fractures and IPyC–SiC debonds.

  16. Temperature of loose coated particles in irradiation tests

    International Nuclear Information System (INIS)

    Conlin, J.A.

    1975-04-01

    An analysis is presented of the temperature of a monolayer bed of loose High-Temperature Gas-Cooled Reactor (HTGR) type fissioning fuel particles in an annular cavity. Both conduction and radiant heat transfer are taken into account, and the effect of particle contact with the annular cavity surfaces is evaluated. Charts are included for the determination of the maximum surface temperature of the particle coating for any size particle or power generation rate in a fuel bed of this type. The charts are intended for the design and evaluation of irradiation experiments on loose beds of coated fuel particles of the type used in HTGRs. Included in an Appendix is a method for estimating the temperature of a particle in circular hole. (U.S.)

  17. Melanosome evolution indicates a key physiological shift within feathered dinosaurs.

    Science.gov (United States)

    Li, Quanguo; Clarke, Julia A; Gao, Ke-Qin; Zhou, Chang-Fu; Meng, Qingjin; Li, Daliang; D'Alba, Liliana; Shawkey, Matthew D

    2014-03-20

    Inference of colour patterning in extinct dinosaurs has been based on the relationship between the morphology of melanin-containing organelles (melanosomes) and colour in extant bird feathers. When this relationship evolved relative to the origin of feathers and other novel integumentary structures, such as hair and filamentous body covering in extinct archosaurs, has not been evaluated. Here we sample melanosomes from the integument of 181 extant amniote taxa and 13 lizard, turtle, dinosaur and pterosaur fossils from the Upper-Jurassic and Lower-Cretaceous of China. We find that in the lineage leading to birds, the observed increase in the diversity of melanosome morphologies appears abruptly, near the origin of pinnate feathers in maniraptoran dinosaurs. Similarly, mammals show an increased diversity of melanosome form compared to all ectothermic amniotes. In these two clades, mammals and maniraptoran dinosaurs including birds, melanosome form and colour are linked and colour reconstruction may be possible. By contrast, melanosomes in lizard, turtle and crocodilian skin, as well as the archosaurian filamentous body coverings (dinosaur 'protofeathers' and pterosaur 'pycnofibres'), show a limited diversity of form that is uncorrelated with colour in extant taxa. These patterns may be explained by convergent changes in the key melanocortin system of mammals and birds, which is known to affect pleiotropically both melanin-based colouration and energetic processes such as metabolic rate in vertebrates, and may therefore support a significant physiological shift in maniraptoran dinosaurs.

  18. Microstructural characterization of second phase irradiated Zircaloy-4 particles

    International Nuclear Information System (INIS)

    Flores, Alejandra V.; Vizcaino, Pablo; Banchik, Abraham D.; Bozzano, Patricia B.; Versaci, Raul A.

    2007-01-01

    X-ray diffraction diagrams of neutron irradiated Zircaloy-4 were obtained at the LNLS with the aim to obtain bulk information about the amorphization process in which the Zircaloy-4 second phase particles (SPPs) undergoes due to neutron irradiation. Owing to the low concentration of the SPPs in the alloy (∼0.4 V %), no data regarding to the bulk were obtained until now. The synchrotron experiences allowed to detect five of the more intense lines of the phase C 14 (SPPs structure) in unirradiated Zircaloy-4: (110) θ, (103) θ, (112) θ, (201) θ and (004) θ in the 34 degrees ≤ θ2≤45 degrees Bragg angle range and others of minor intensity. The diagrams of the samples irradiated at moderate doses (1020n/cm 2 ) show these lines even in the as received samples. In contrast, none of these lines are observed for high fluence samples (∼1022neutrons/cm 2 ). In addition, in similar high fluence samples annealed 24 h or 72 h at 600 C degrees the intensity rises just at the 2q range where the C 14 lines were observed, showing a wide peak. That peak is interpreted as a result of the superposition of unresolved diffraction lines corresponding to the Zircaloy SPPs which are in a reconstitution process of crystallization. Analytical Electron Microscopy techniques were used, in order to study the effects on the Zircaloy-4 SPPs and compared with samples of the same material without irradiation. Spots in SAD patterns of non irradiated SPPS, evidences the presence of a C 14 structure, but in irradiated SSP SAD patterns evidences the beginning of an amorphization process. Another important feature to point out is the different Fe / Cr ratio presented in both irradiated and non irradiated SSPs. In non irradiated precipitates the Fe / Cr ratio is approximately 1.5, while in irradiated precipitates the Fe / Cr ratio becomes near 1.0. (author) [es

  19. Microstructure evolution of recrystallized Zircaloy-4 under charged particles irradiation

    Science.gov (United States)

    Gaumé, M.; Onimus, F.; Dupuy, L.; Tissot, O.; Bachelet, C.; Mompiou, F.

    2017-11-01

    Recrystallized zirconium alloys are used as nuclear fuel cladding tubes of Pressurized Water Reactors. During operation, these alloys are submitted to fast neutron irradiation which leads to their in-reactor deformation and to a change of their mechanical properties. These phenomena are directly related to the microstructure evolution under irradiation and especially to the formation of -type dislocation loops. In the present work, the radiation damage evolution in recrystallized Zircaloy-4 has been studied using charged particles irradiation. The loop nucleation and growth kinetics, and also the helical climb of linear dislocations, were observed in-situ using a High Voltage Electron Microscope (HVEM) under 1 MeV electron irradiation at 673 and 723 K. In addition, 600 keV Zr+ ion irradiations were conducted at the same temperature. Transmission Electron Microscopy (TEM) characterizations have been performed after both types of irradiations, and show dislocation loops with a Burgers vector belonging to planes close to { 10 1 bar 0 } first order prismatic planes. The nature of the loops has been characterized. Only interstitial dislocation loops have been observed after ion irradiation at 723 K. However, after electron irradiation conducted at 673 and 723 K, both interstitial and vacancy loops were observed, the proportion of interstitial loops increasing as the temperature is increased. The loop growth kinetics analysis shows that as the temperature increases, the loop number density decreases and the loop growth rate tends to increase. An increase of the flux leads to an increase of the loop number density and a decrease of the loop growth rate. The results are compared to previous works and discussed in the light of point defects diffusion.

  20. Luminescence imaging of water during alpha particle irradiation

    Science.gov (United States)

    Yamamoto, Seiichi; Komori, Masataka; Koyama, Shuji; Toshito, Toshiyuki

    2016-05-01

    The luminescence imaging of water using the alpha particle irradiation of several MeV energy range is thought to be impossible because this alpha particle energy is far below the Cerenkov-light threshold and the secondary electrons produced in this energy range do not emit Cerenkov-light. Contrary to this consensus, we found that the luminescence imaging of water was possible with 5.5 MeV alpha particle irradiation. We placed a 2 MBq of 241Am alpha source in water, and luminescence images of the source were conducted with a high-sensitivity, cooled charge-coupled device (CCD) camera. We also carried out such imaging of the alpha source in three different conditions to compare the photon productions with that of water, in air, with a plastic scintillator, and an acrylic plate. The luminescence imaging of water was observed from 10 to 20 s acquisition, and the intensity was linearly increased with time. The intensity of the luminescence with the alpha irradiation of water was 0.05% of that with the plastic scintillator, 4% with air, and 15% with the acrylic plate. The resolution of the luminescence image of water was better than 0.25 mm FWHM. Alpha particles of 5.5 MeV energy emit luminescence in water. Although the intensity of the luminescence was smaller than that in air, it was clearly observable. The luminescence of water with alpha particles would be a new method for alpha particle detection and distribution measurements in water.

  1. Luminescence imaging of water during alpha particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Seiichi, E-mail: s-yama@met.nagoya-u.ac.jp [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Komori, Masataka; Koyama, Shuji [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center (Japan)

    2016-05-21

    The luminescence imaging of water using the alpha particle irradiation of several MeV energy range is thought to be impossible because this alpha particle energy is far below the Cerenkov-light threshold and the secondary electrons produced in this energy range do not emit Cerenkov-light. Contrary to this consensus, we found that the luminescence imaging of water was possible with 5.5 MeV alpha particle irradiation. We placed a 2 MBq of {sup 241}Am alpha source in water, and luminescence images of the source were conducted with a high-sensitivity, cooled charge-coupled device (CCD) camera. We also carried out such imaging of the alpha source in three different conditions to compare the photon productions with that of water, in air, with a plastic scintillator, and an acrylic plate. The luminescence imaging of water was observed from 10 to 20 s acquisition, and the intensity was linearly increased with time. The intensity of the luminescence with the alpha irradiation of water was 0.05% of that with the plastic scintillator, 4% with air, and 15% with the acrylic plate. The resolution of the luminescence image of water was better than 0.25 mm FWHM. Alpha particles of 5.5 MeV energy emit luminescence in water. Although the intensity of the luminescence was smaller than that in air, it was clearly observable. The luminescence of water with alpha particles would be a new method for alpha particle detection and distribution measurements in water.

  2. Particle velocity measurements in laser irradiated foils using ORVIS

    International Nuclear Information System (INIS)

    Sheffield, S.A.; Fisk, G.A.

    1983-01-01

    Aluminum foils from 2- to 200-μm thick have been subjected to a Nd:YAG laser pulse of low irradiance (10 9 W/cm 2 , approx. 10 ns pulse) to produce laser-driven shocks in the foils. The particle velocity history of the foil side opposite the laser deposition was monitored with nanosecond resolution by a velocity interferometer system called ORVIS. These histories indicate a shock reverberation process accelerates the foil. Peak foil velocities can be adequately calculated using a ricket propulsion model developed from experiments at much higher irradiances. A velocity of 1 km/s was developed in a 2-μm-thick free foil in a time of 50 ns. Water-confined foils attained peak particle velocities about three times higher than those of free foils

  3. Impact of electron irradiation on particle track etching response in ...

    Indian Academy of Sciences (India)

    In the present work, attempts have been made to investigate the modification in particle track etching response of polyallyl diglycol carbonate (PADC) due to impact of 2 MeV electrons. PADC samples pre-irradiated to 1, 10, 20, 40, 60, 80 and 100 Mrad doses of 2 MeV electrons were further exposed to 140 MeV 28Si beam ...

  4. Failure of the capsule for coated particles irradiation

    International Nuclear Information System (INIS)

    Yamaki, Jikei; Nomura, Yasushi; Nagamatsuya, Takaaki; Yamahara, Takeshi; Sakai, Haruyuki

    1975-10-01

    During operation cycle No. 27 of the JMTR (Japan Material Testing Reactor) on May 20, 1974, leakage of the fission product gas occurred from the capsule 72F-7A, which contained coated particles for the irradiation; the coated particles are for the development of a multi-purpose high temperature gas cooled reactor. The capsule was designed for heat 1600 0 C. Three nickel plates as the heat reflector were sandwiched in between the plates of titanium and zirconium, which were adsorbents for the impurity gases in the cladding tube (Nb-1%Zr). Temperatures of the plates were about 1000 0 C under the irradiation, so one metal diffused into the other metal through interfaces, resulting in the formation of an alloy. Its melting point was lower than those of metals in the capsule. The cladding material Nb-1%Zr was melted by the alloy and finally a pin hole developed through the cladding. The process of failure, design of the capsule, post-irradiation test of the capsule and the failure-reproducing experiment with a mock-up capsule are described. (auth.)

  5. On transient irradiation behavior of HTGR fuel particles

    International Nuclear Information System (INIS)

    Mortenson, S.C.; Okrent, D.

    1977-01-01

    An examination of HTGR TRISO coated fuel particles was made in which the particles' stress-strain histories were determined during both steady-state and transient operating conditions. The basis for the examination was a modified version of a computer code written by Kaae which assumed spherical symmetry, isotropic thermal expansion, isotropic elastic constants, time-temperature-irradiation invariant materials properties, and steady state operation during particle exposure. Additionally, the Kaae code modelled potential separation of layers at the SiC-inner PyC interface and considered that several entrapped fission products could exist in either the gaseous or solid state, dependent upon particle operating conditions. Using the modified code which modelled transient behavior in a quasi-static fashion, a series of both steady-state and transient operating condition computer simulations was made. For the former set of runs, a candidate set of particle dimensions and a nominal set of materials' properties was assumed. Layer thicknesses were assumed to be normally distributed about the nominal thickenesses and a probability distribution of SiC tensile stresses was generated; sensitivity of the stress distribution to assumed standard deviation of the layer thicknesses was acute. Further, this series of steady-state runs demonstrated that for certain combinations of the assumed PyC-SiC bond interface strength and irradiation-induced creep constant, anomalous predicted stresses may be obtained in the PyC layers. The steady-state runs also suggest that transient behavior would most likely not be significant at fast neutron exposures below about 10 21 NVT due to both low fission gas pressure and likely beneficial interface separation

  6. Characteristic lesions in mouse retina irradiated with accelerated iron particles

    International Nuclear Information System (INIS)

    Malachowski, M.J.; Philpott, D.E.; Corbett, R.L.; Tobias, C.A.

    1981-01-01

    A program is underway to determine the radiation hazards of HZE particles using the Bevalac, a heavy-ion accelerator at LBL. Our earlier work with helium, carbon, neon, and argon particles, and exposure to rats to HZE particles in space flight demonstrated some deleterious biological effects. TEM studies have shown that some visual cells were missing and dislocated; these were termed channel lesions. Recently obtained is evidence that a single iron HZE particle may affect a series of cells. Mice were irradiated with 0.1, 0.3, 1, 10, or 25 rad of 590 MeV/amu initial kinetic energy iron particles in groups of 10 animals per dose point. Irradiated and control animals were sacrificed at intervals from one week to two years postirradiation. The eye samples were dehydrated, critical points dried with freon, fractured, and Au-Pd coated for SEM, or plastic embedded, sectioned, and stained for TEM. Additionally, dry fractured samples viewed with the SEM were embedded in plastic, sectioned, and stained for the TEM. Characteristic tunnel shaped lesions were observed with the SEM. Stereo pairs showed tunnels of various lengths up to 100 μm. Light microscopy of serially cut sections from the same material had vacuoles (V) extending the same length. TEM of the same specimen and specimens prepared only for TEM exhibited large vacuoles, greater than or equal to 2 μm, in the inner segment (IS) and outer segment (OS) layers. Severe membrane disruption was found bordering the vacuoles and gross nuclear degeneration (ND) and loose tissue (LT) were seen in the outer nuclear layer (ONL). The number of lesions increased with increasing dose. Microscopy of the control retina failed to demonstrate similar lesions

  7. Amorphization of complex ceramics by heavy-particle irradiations

    International Nuclear Information System (INIS)

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

    1994-11-01

    Complex ceramics, for the purpose of this paper, include materials that are generally strongly bonded (mixed ionic and covalent), refractory and frequently good insulators. They are distinguished from simple, compact ceramics (e.g., MgO and UO 2 ) by structural features which include: (1) open network structures, best characterized by a consideration of the shape, size and connectivity of coordination polyhedra; (2) complex compositions which characteristically lead to multiple cation sites and lower symmetry; (3) directional bonding; (4) bond-type variations within the structure. The heavy particle irradiations include ion-beam irradiations and recoil-nucleus damage resulting from a-decay events from constituent actinides. The latter effects are responsible for the radiation-induced transformation to the metamict state in minerals. The responses of these materials to irradiation are complex, as energy may be dissipated ballistically by transfer of kinetic energy from an incident projectile or radiolytically by conversion of radiation-induced electronic excitations into atomic motion. This results in isolated Frenkel defect pairs, defect aggregates, isolated collision cascades or bulk amorphization. Thus, the amorphization process is heterogeneous. Only recently have there been systematic studies of heavy particle irradiations of complex ceramics on a wide variety of structure-types and compositions as a function of dose and temperature. In this paper, we review the conditions for amorphization for the tetragonal orthosilicate, zircon [ZrSiO 4 ]; the hexagonal orthosilicate/phosphate apatite structure-type [X 10 (ZO 4 ) 6 (F,Cl,O) 2 ]; the isometric pyrochlores [A 1-2 B 2 O 6 (O,OH,F) 0-1p H 2 O] and its monoclinic derivative zirconotite [CaZrTi 2 O 7 ]; the olivine (derivative - hcp) structure types, α- VI A 2 IV BO 4 , and spinel (ccp), γ- VI A 2 IV BO 4

  8. Trends in nanosecond melanosome microcavitation up to 1540 nm

    Science.gov (United States)

    Schmidt, Morgan S.; Kennedy, Paul K.; Noojin, Gary D.; Vincelette, Rebecca L.; Thomas, Robert J.; Rockwell, Benjamin A.

    2015-09-01

    Thresholds for microcavitation of bovine and porcine melanosomes were previously reported, using single nanosecond (ns) laser pulses in the visible (532 nm) and the near-infrared (NIR) from 1000 to 1319 nm. Here, we report average radiant exposure thresholds for bovine melanosome microcavitation at additional NIR wavelengths up to 1540 nm, which range from ˜0.159 J/cm2 at 800 nm to 4.5 J/cm2 at 1540 nm. Melanosome absorption coefficients were also estimated, and decreased with increasing wavelength. These values were compared to retinal pigment epithelium coefficients, and to water absorption, over the same wavelength range. Corneal total intraocular energy retinal damage threshold values were estimated and compared to the previous (2007) and recently changed (2014) maximum permissible exposure (MPE) safe levels. Results provide additional data that support the recent changes to the MPE levels, as well as the first microcavitation data at 1540 nm, a wavelength for which melanosome microcavitation may be an ns-pulse skin damage mechanism.

  9. Effects of heavy particle irradiation on central nervous system

    International Nuclear Information System (INIS)

    Nojima, Kumie; Nakadai, Taeko; Khono, Yukio; Nagaoka, Shunji

    2004-01-01

    Effects of low dose heavy particle radiation to central nervous system were studied using mouse neonatal brain cells in culture exposed to heavy ions and X ray at fifth days of the culture. The subsequent biological effects were evaluated by an induction of apoptosis and the survivability of neurons focusing on the dependencies of the animal strains with different genetic types, and linear energy transfer (LET) of the different nucleons. Of the three mouse strains tested, SCID, B6, B6C3F1 and C3H, used for brain cell culture, SCID was the most sensitive. Radiation sensitivity of these cells ware SCID>B6>B6C3F1>C3H to both X-ray and carbon ion (290 MeV/n) when compared by 10% apoptotic induction. The LET dependency was compared with using SCID cells exposing to different ions, (X, C, Si, Ar, and Fe). Although no detectable LET dependency was observed at higher dose than 1 Gy, an enhancement was observed in the high LET region and at lower dose than 0.5 Gy. The survivability profiles of the neurons were different in the mouse strains and ions. Memory and learning function of adult mice were studied using water maze test after localized carbon- or iron-ion irradiation to hippocampus area. Memory function were rapidly decrease after irradiation both ions. C-ion group were recovered 20 weeks after irradiation, but Iron group were different. (author)

  10. The slaty mutation affects the morphology and maturation of melanosomes in the mouse melanocytes.

    Science.gov (United States)

    Hirobe, Tomohisa; Abe, Hiroyuki

    2006-10-01

    The slaty (Dct(slt)) mutation is known to reduce the activity of dopachrome tautomerase in melanocytes and to reduce the melanin content in skin, hairs and eyes. Although the melanosomes in slaty melanocytes are reported to be eumelanosome-like, detailed melanosome biogenesis is not well studied. To address this point, melanosomes in neonatal epidermal melanocytes from wild-type (Dct+/Dct+) mice at the slaty locus as well as its congenic mouse mutant (Dct(slt)/Dct(slt)) in serum-free primary culture were observed under the electron microscope. Wild-type melanocytes possessed exclusively elliptical melanosomes with internal longitudinal structures, whereas in mutant melanocytes, numerous spherical melanosomes with globular depositions of pigment and elliptical melanosomes as well as mixed type of the two melanosomes were observed. Mature stage IV melanosomes were greatly decreased in mutant melanocytes, whereas immature stage III melanosomes were more numerous than in wild-type melanocytes. These results suggest that the slaty mutation affects the morphology and maturation of melanosomes in mouse melanocytes.

  11. Study on cellular genotoxicities induced by alpha particles irradiation in combination with NNK treatment

    International Nuclear Information System (INIS)

    Li Ping; Yang Zhihua; Pan Xiujie; Cao Zhenshan; Mi Na; Chen Zhongmin; Liu Gang; Wei Han; Li Huiying; Zhu Maoxiang

    2006-01-01

    Objective: To investigate cellular genotoxicities of aplha particles irradiation in combination with NNK treatment. Methods: Exponentially growing immortalized human bronchial epithelial cells were divided into the normal control group (NC), alpha particles irradiation (α), NNK administration group (NNK), NNK administration (100 μg/ml) followed by alpha particles irradiation group (NNK + α), and alpha particles irradiation followed by NNK administration (100 μg/ml) group (μ + NNK). DNA damage were detected by single cell gel electrophoresis (SCGE); multinuclear cell assay was used to detect the frequency of the HPRT gene mutation; cell micronucleus frequency were detected by cytogenetic methods. Results: In the group exposed to both alpha particles irradiation and NNK, DNA damage, HPRT gene mutation frequency, and cell micronucleus frequency were significantly higher than those in the same dose groups irradiated with alpha particles or NNK administration alone. Subtracted the NNK effect, DNA damage, HPRT gene mutation frequency and cell micronucleus frequency in the group irradiated by alpha particles in combination with NNK administration were significantly higher than those of alpha particles irradiation alone. Conclusion: The genotoxicity of alpha particles irradiation in combination with NNK administration had synergistic effect. (authors)

  12. Experimental central nervous system injury after charged-particle irradiation

    International Nuclear Information System (INIS)

    Rodriguez, A.; Levy, R.P.; Fabrikant, J.I.

    1991-01-01

    This paper reports on the development of definite paralytic signs, used as an endpoint for the determination of latent periods, which reflect the presence of damage but do not reveal its pathologic characteristics. Paralysis was a nonstochastic effect for which both the probability and severity vary with dose and for which a threshold of dose-response existed. Histologically the primary lesion induced by both charged-particle irradiation and X- or γ-radiation was demyelination and necrosis of the white matter. This has been attributed generally to damage to the oligodendrocytes. The spinal cord tolerance toward fractionated helium radiation was similar to X- or γ-radiation, but the spinal cord was much more sensitive to heavier charged-particle radiation. There was much less sparing and decreased tissue tolerance in the high-LET spread Bragg peak regions of carbon- and neon-ion beams that in the plateau regions. A radiologic model for effects in CNS after charged-particle radiation indicated that the α/β values, a measure of tissue repair capacity, increased with LET as predicted. The α/β values for spinal cord injury with neon range from 2.52 to 12.0 depending on the LET; for helium, the α/β value was 1.52, similar to values for X rays

  13. Mechanism of melanosomes action in antioxidant reactions following optic irradiation

    Science.gov (United States)

    Lapina, Victoria A.; Dontsov, Alexander E.; Sakina, Natalia L.; Ostrovsky, Michail A.

    1996-05-01

    Hyphema is often associated with traumatic eye injuries. Its blood is subjected to considerable changes in aqueous humor and causes toxic effect on eye tissues. The metabolism disturbances in eye tissues unfavorably affecting their cell structures play a significant role in the development of pathologic conditions in cases of intraocular hemorrhages. This is to be attributed to the correlation of lipid peroxidation (LP) processes and antioxidant system (AOS) activity of both the cellular membrane and its environment necessary for maintaining cell homeostasis as a whole. The aim of the present work is an experimental study of LP processes of aqueous humor (AH) in total traumatic hyphema (TTH) after magnet-laser stimulation different doses (3 and 6 minutes). TTH and aqueous humor collection were made on the eyes on rabbit (Schinchilla) according to Krasnov A.M. under the local anaesthesia (dicaine 0.25%). The study of biochemical aqueous indices was carried out on healthy eyes and after development of hyphema on day 1, 3, 5, 7, 10, 14, 30, and 45. The animals were divided into three groups: in the first group the biochemical indices were defined in the aqueous humor in TTH; in the second and the third groups the similar investigation was carried out after magnet- laser radiation with 3 and 6 minutes exposition. The malonic dialdehyde (MDA) was defined according to Ishihara, Shiff's bases -- and their concentration was determined on the total amount of lipids (reagent kit of 'Lachema'). He-Ne laser (with power density of 0.05 mVt) was used, streaming impulsed magnet field voltage being 10 mTl. The magnet head of a magnet radiator was fixed 0.5 cm from the eye; laser beam being sent to the central hole of the magnet head. The duration of exposure was 3 minutes in the second group and 6 minutes in the third group, daily for 10 days. Significant increase of LP product concentration level with two clear ascending peaks was seen on the third and tenth days in the first group. The maximal increase of these indices was noted on the third day, that coincides with hemolysis of outpouring blood and release of powerful LP processes initiators into aqueous humor -- that is haemoglobin and Fe++2. The MDA and Shiff's bases concentration levels increased equally during this period with reference to their initial data, whereas on the tenth day the level of Shiff's bases concentration became higher than the MDA amount level. The normalized values of the indices studied were obtained on the 30 - 45th days. The use of magnet-laser radiation caused the significant fall in MDA concentration and Shiff's bases in aqueous humor in TTH in the second group (1.8 and 1.7 correspondingly). On the 7th - 10th days already the values of indices studied were reliably similar to norm (P greater than 0.05). In the third group the levels of LP product concentration fell in the first phase of hyphema resolution. It had been determined that the MDA values were lower than the values of indices of the first group on the third - fifth days (1.5 and 1.7 correspondingly). The values of Shiff's bases on the first day were 1.4 lower than the indices of the first group and were reliably similar to indices of the first group on the third - seventh days (P greater than 0.05).

  14. Spectral Analysis by XANES Reveals that GPNMB Influences the Chemical Composition of Intact Melanosomes

    Energy Technology Data Exchange (ETDEWEB)

    T Haraszti; C Trantow; A Hedberg-Buenz; M Grunze; M Anderson

    2011-12-31

    GPNMB is a unique melanosomal protein. Unlike many melanosomal proteins, GPNMB has not been associated with any forms of albinism, and it is unclear whether GPNMB has any direct influence on melanosomes. Here, melanosomes from congenic strains of C57BL/6J mice mutant for Gpnmb are compared to strain-matched controls using standard transmission electron microscopy and synchrotron-based X-ray absorption near-edge structure analysis (XANES). Whereas electron microscopy did not detect any ultrastructural changes in melanosomes lacking functional GPNMB, XANES uncovered multiple spectral phenotypes. These results directly demonstrate that GPNMB influences the chemical composition of melanosomes and more broadly illustrate the potential for using genetic approaches in combination with nano-imaging technologies to study organelle biology.

  15. AP-1/KIF13A Blocking Peptides Impair Melanosome Maturation and Melanin Synthesis

    Directory of Open Access Journals (Sweden)

    Cécile Campagne

    2018-02-01

    Full Text Available Melanocytes are specialized cells that generate unique organelles called melanosomes in which melanin is synthesized and stored. Melanosome biogenesis and melanocyte pigmentation require the transport and delivery of melanin synthesizing enzymes, such as tyrosinase and related proteins (e.g., TYRP1, from endosomes to maturing melanosomes. Among the proteins controlling endosome-melanosome transport, AP-1 together with KIF13A coordinates the endosomal sorting and trafficking of TYRP1 to melanosomes. We identify here β1-adaptin AP-1 subunit-derived peptides of 5 amino acids that block the interaction of KIF13A with AP-1 in cells. Incubating these peptides with human MNT-1 cells or 3D-reconstructed pigmented epidermis decreases pigmentation by impacting the maturation of melanosomes in fully pigmented organelles. This study highlights that peptides targeting the intracellular trafficking of melanocytes are candidate molecules to tune pigmentation in health and disease.

  16. Study on cytotoxicities induced by alpha particle irradiation combined with NNK treatment

    International Nuclear Information System (INIS)

    Li Ping; Yang Zhihua; Pan Xiujie; Cao Zhenshan; Mi Na; Chen Zhongmin; Liu Gang; Wei Han; Li Huiyin; Zhu Maoxiang

    2006-01-01

    Objective: To investigate cytotoxicities of alpha-particle irradiation combined with NNK treatment. Methods: Exponentially growing immortalized human bronchial epithelial cells were divided into normal control group (NC), alpha particle irradiation group (α), NNK administration group (NNK), NNK administration (100 μg/ml) followed by alpha particle irradiation group (NNK + α), and alphaparticle irradiation followed by NNK administration (100 μg/ml) group (α + NNK). Cell survival fractions were measured by cloning rate of low-density plating cell. Ethidium bromide and 2', 7'-dichlorofluorescein, fluorescent products of the membrane-permeable dyes hydroethine and 2', 7'-dichloroflurescindiacetate were used to monitor the inarticulate reactive oxygen species (ROS) . Damage to membrane permeability was evaluated through testing LDH activity in medium. Results: In the groups exposed to both alpha particles and NNK, the survival rates were significantly lower than that of the groups administrated with the same dose of alpha particles or NNK alone. The levels of intracellular ROS and the activity of LDH in medium were significantly higher than that of the groups administrated with the same dose of alpha particles or NNK alone. Subtracted the NNK effect, the survival rates of the groups received both alpha particle irradiation and NNK treatment were significantly lower than that of alpha particle irradiated only group. However, the intracellular ROS level and the activity of LDH in medium were significantly higher than that of alpha-particle irradiated only group. In addition, the survival rates of the cells in groups exposed to alpha particle irradiation followed by NNK administration were significantly lower than that of cells treated with NNK administration followed by alpha particle irradiation. Conclusions: Alpha particle irradiation and NNK administration had synergisticity in cytotoxicity, and furthermore different schedules of the administration resulted in

  17. Hyperosmotic stress reduces melanin production by altering melanosome formation.

    Science.gov (United States)

    Bin, Bum-Ho; Bhin, Jinhyuk; Yang, Seung Ha; Choi, Dong-Hwa; Park, Kyuhee; Shin, Dong Wook; Lee, Ai-Young; Hwang, Daehee; Cho, Eun-Gyung; Lee, Tae Ryong

    2014-01-01

    Many tissues of the human body encounter hyperosmotic stress. The effect of extracellular osmotic changes on melanin production has not yet been elucidated. In this study, we determined that hyperosmotic stress induced by organic osmolytes results in reduced melanin production in human melanoma MNT-1 cells. Under hyperosmotic stress, few pigmented mature melanosomes were detected, but there was an increase in swollen vacuoles. These vacuoles were stained with an anti-M6PR antibody that recognizes late endosomal components and with anti-TA99 and anti-HMB45 antibodies, implying that melanosome formation was affected by hyperosmotic stress. Electron microscopic analysis revealed that the M6PR-positive swollen vacuoles were multi-layered and contained melanized granules, and they produced melanin when L-DOPA was applied, indicating that these vacuoles were still capable of producing melanin, but the inner conditions were not compatible with melanin production. The vacuolation phenomenon induced by hyperosmotic conditions disappeared with treatment with the PI3K activator 740 Y-P, indicating that the PI3K pathway is affected by hyperosmotic conditions and is responsible for the proper formation and maturation of melanosomes. The microarray analysis showed alterations of the vesicle organization and transport under hyperosmotic stress. Our findings suggest that melanogenesis could be regulated by physiological conditions, such as osmotic pressure.

  18. New insights into melanosome transport in vertebrate pigment cells.

    Science.gov (United States)

    Aspengren, Sara; Hedberg, Daniel; Sköld, Helen Nilsson; Wallin, Margareta

    2009-01-01

    Pigment cells of lower vertebrates provide an excellent model to study organelle transport as they specialize in the translocation of pigment granules in response to defined chemical cues. This review will focus on the well-studied melanophore/melanocyte systems in fish, amphibians, and mammals. We will describe the roles of melanin, melanophores, and melanocytes in animals, current views on how the three motor proteins dynein, kinesin, and myosin-V are involved in melanosome transport along microtubules and actin filaments, and how signal transduction pathways regulate the activities of the motors to achieve aggregation and dispersion of melanosomes. We will also describe how melanosomes are transferred to surrounding skin cells in amphibians and mammals. Comparative studies have revealed that the ability of physiological color change is lost during evolution while the importance of morphological color change, mainly via transfer of pigment to surrounding skin cells, increases. In humans, pigment mainly has a role in protection against ultraviolet radiation, but also perhaps in the immune system.

  19. Unstable structure of ribosomal particles synthesized in. gamma. -irradiated Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, H; Morita, K [National Inst. of Radiological Sciences, Chiba (Japan)

    1975-06-01

    Stability of Escherichia coli ribosomes newly synthesized after ..gamma..-irradiation was compared with that of normal ribosomes. The ribosomal particles around 70-S synthesized in irradiated cells were more sensitive to digestion by pancreatic ribonuclease A. A larger number of the salt-unstable '50-S' precursor particles existed in the extract from irradiated cells than in the extract from unirradiated cells. These facts suggest that ribosomal particles, synthesized during an earlier stage in irradiated cells, maintain an incomplete structure even though they are not distinguishable from normal ribosomes by means of sucrose density-gradient centrifugation.

  20. Detection of Misdistribution of Tyrosinase from Melanosomes to Lysosomes and Its Upregulation under Psoralen/Ultraviolet A with a Melanosome-Targeting Tyrosinase Fluorescent Probe.

    Science.gov (United States)

    Zhou, Jin; Shi, Wen; Li, Lihong; Gong, Qiuyu; Wu, Xiaofeng; Li, Xiaohua; Ma, Huimin

    2016-04-19

    Tyrosinase is regarded as an important biomarker of melanoma cancer, and its metabolism is closely related to some severe skin diseases such as vitiligo. Since tyrosinase is mainly located in the melanosomes of melanocytes, a probe that can specifically detect and image tysosinase in melanosomes would be in urgent demand to study the behavior of the enzyme in cells, but unfortunately, no melanosome-targeting tyrosinase fluorescent probe has been reported so far to the best of our knowledge. In this work, we have developed such a new probe, Mela-TYR, which bears morpholine as a melanosome-targeting group and 4-aminophenol as a tyrosinase reaction group. The probe exhibits not only a highly sensitive and selective off-on response to tyrosinase via oxidization cleavage, but also an accurate targeting ability toward the acidic organelles of melanosomes and lyososomes, which is validated by colocalization experiments with mCherry-tagged melanosomes as well as DND-99 (a commercial dye). The probe has been used to image the relative contents of tyrosinase in different cells. Notably, because of the tyrosinase deficiency in normal lysosomes, the probe only fluoresces in melanosomes in principle although it can accumulate in other acidic organelles like lysosomes. By virtue of this property, the misdistribution of tyrosinase from melanosomes to lysosomes in murine melanoma B16 cells under the stimulation of inulavosin is imaged in real time for the first time. Moreover, the upregulation of melanosomal tyrosinase in live B16 cells under the stimulation of psoralen/ultraviolet A is detected with our probe, and this upregulation is further verified by standard colorimetric assay. The probe provides a simple, visual method to study the metabolism of tyrosinase in cells and shows great potential in clinical diagnosis and treatments of tyrosinase-associated diseases.

  1. Influence of Magnolol on the bystander effect induced by alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wong, T.P.W.; Law, Y.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Tse, A.K.W.; Fong, W.F. [Research and Development Division, School of Chinese Medicine, Hong Kong Baptist University, Baptist University Road, Kowloon Tong (Hong Kong); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)], E-mail: peter.yu@cityu.edu.hk

    2010-04-15

    In this work, the influence of Magnolol on the bystander effect in alpha-particle irradiated Chinese hamster ovary (CHO) cells was examined. The bystander effect was studied through medium transfer experiments. Cytokinesis-block micronucleus (CBMN) assay was performed to quantify the chromosome damage induced by alpha-particle irradiation. Our results showed that the alpha-particle induced micronuclei (MN) frequencies were suppressed with the presence of Magnolol.

  2. Irradiation of blood by 238Pu alpha particles

    International Nuclear Information System (INIS)

    Hungate, F.P.; Riemath, W.F.; Culver, G.G.; Gillis, M.F.; Ragan, H.A.

    1976-01-01

    A developmental 238 Pu blood irradiator produced no evidence of lymphopenia in a dog. Irradiation continued for a year at an estimated rate of about 100 rads/day, but this dosimetry is highly uncertain

  3. Development of a Charged Particle Microbeam for Single-Particle Subcellular Irradiations at the MIT Laboratory for Accelerator Beam Application

    International Nuclear Information System (INIS)

    Yanch, Jacquelyn C.

    2004-01-01

    The development of a charged particle microbeam for single particle, subcellular irradiations at the Massachusetts Institute of Technology Laboratory for Accelerator Beam Applications (MIT LABA) was initiated under this NEER aeard. The Microbeam apparatus makes use of a pre-existing electrostatic accelerator with a horizontal beam tube

  4. Effects of heavy particle irradiation on central nervous system

    International Nuclear Information System (INIS)

    Nojima, Kumie; Liu Cuihua; Nagaoka, Shunji

    2003-01-01

    Effects of low dose heavy particle radiation to central nervous system were studied using mouse neonatal brain cells in culture exposed to heavy ions and X ray at fifth days of the culture. The subsequent biological effects were evaluated by an induction of apoptosis and the survivability of neurons focusing on the dependencies of the animal strains with different genetic types, and linear energy transfer (LET) of the different nucleons. Of the three mouse strains tested, severe combined immunodeficiency (SCID), B6 and C3H, used for brain cell culture, SCID was the most sensitive and C3H the least sensitive to both X-ray and carbon ion (290 MeV/n) when compared by 10% apoptotic induction. The LET dependency was compared with using SCID cells exposing to different ions, (X, C, Si, Ar, and Fe). Although no detectable LET dependency was observed at higher dose than 1 Gy, an enhancement was observed in the high LET region and at lower dose than 0.5 Gy. The survivability profiles of the neurons were different in the mouse strains and ions. Memory and learning function of adult mice were studied using water maze test after localized carbon- or iron-ion irradiation to hippocampus area. (author)

  5. Secondary particle tracks generated by ion beam irradiation

    Science.gov (United States)

    García, Gustavo

    2015-05-01

    The Low Energy Particle Track Simulation (LEPTS) procedure is a powerful complementary tool to include the effect of low energy electrons and positrons in medical applications of radiation. In particular, for ion-beam cancer treatments provides a detailed description of the role of the secondary electrons abundantly generated around the Bragg peak as well as the possibility of using transmuted positron emitters (C11, O15) as a complement for ion-beam dosimetry. In this study we present interaction probability data derived from IAM-SCAR corrective factors for liquid environments. Using these data, single electron and positron tracks in liquid water and pyrimidine have been simulated providing information about energy deposition as well as the number and type of interactions taking place in any selected ``nanovolume'' of the irradiated area. In collaboration with Francisco Blanco, Universidad Complutense de Madrid; Antonio Mu noz, Centro de Investigaciones Energéticas Medioambientales y Tecnológicas and Diogo Almeida, Filipe Ferreira da Silva, Paulo Lim ao-Vieira, Universidade Nova de Lisboa. Supported by the Spanish and Portuguese governments.

  6. Bystander effect of alpha-particle irradiation on mutagenicity and its associated mechanism

    International Nuclear Information System (INIS)

    Lu Ying; Yang Zhihua; Cao Zhenshan; Fan Feiyue; Zhu Maoxiang

    2004-01-01

    The work is to investigate α-particle irradiation-induced bystander effects on the mutagenicity in human chromosome 11 in the human-hamster hybrid (A L cells) and its possible mechanism. A L cells were used for assaying mutation rates of human chromosome 11 through screening mutants in the presence of anti-CD59 surface antigen antibody (S1) and complement. A grid was interposed between α-particle source and the cells being irradiated, so as to fix proportion of the irradiated cells (15%) and the bystander effects on the mutagenicity were detected. Free radical scavenger DMSO and intercellular communication inhibitor Lindane were selected to investigate the potential mechanism of α-particle induced bystander effect. There was clear dose-dependent relationship between mutation rate and the dose of alpha particle radiation. However, the mutant fractions of cell population shielded by the grid in α-particle irradiation system were much higher than the expected levels of irradiated cells. Lindane, but not DMSO, could obviously decrease this bystander effect induced by α-particle irradiation. Alpha-particle irradiation can induce bystander effect on the mutagenicity, in which intercellular communication may play important roles

  7. Melanosomes are transferred from melanocytes to keratinocytes through the processes of packaging, release, uptake, and dispersion.

    Science.gov (United States)

    Ando, Hideya; Niki, Yoko; Ito, Masaaki; Akiyama, Kaoru; Matsui, Mary S; Yarosh, Daniel B; Ichihashi, Masamitsu

    2012-04-01

    Recent studies have described the role of shedding vesicles as physiological conveyers of intracellular components between neighboring cells. Here we report that melanosomes are one example of shedding vesicle cargo, but are processed by a previously unreported mechanism. Pigment globules were observed to be connected to the filopodia of melanocyte dendrites, which have previously been shown to be conduits for melanosomes. Pigment globules containing multiple melanosomes were released from various areas of the dendrites of normal human melanocytes derived from darkly pigmented skin. The globules were then captured by the microvilli of normal human keratinocytes, also derived from darkly pigmented skin, which incorporated them in a protease-activated receptor-2 (PAR-2)-dependent manner. After the pigment globules were ingested by the keratinocytes, the membrane that surrounded each melanosome cluster was gradually degraded, and the individual melanosomes then spread into the cytosol and were distributed primarily in the perinuclear area of each keratinocyte. These results suggest a melanosome transfer pathway wherein melanosomes are transferred from melanocytes to keratinocytes via the shedding vesicle system. This packaging system generates pigment globules containing multiple melanosomes in a unique manner.

  8. The semiconductor doping with radiation defects via proton and alpha-particle irradiation. Review

    CERN Document Server

    Kozlov, V A

    2001-01-01

    Paper presents an analytical review devoted to semiconductor doping with radiation defects resulted from irradiation by light ions, in particular, by protons and alpha-particles. One studies formation of radiation defects in silicon, gallium arsenide and indium phosphide under light ion irradiation. One analyzes effect of proton and alpha-particle irradiation on electric conductivity of the above-listed semiconducting materials. Semiconductor doping with radiation defects under light ion irradiation enables to control their electrophysical properties and to design high-speed opto-, micro- and nanoelectronic devices on their basis

  9. SILICON CARBIDE GRAIN BOUNDARY DISTRIBUTIONS, IRRADIATION CONDITIONS, AND SILVER RETENTION IN IRRADIATED AGR-1 TRISO FUEL PARTICLES

    Energy Technology Data Exchange (ETDEWEB)

    Lillo, T. M.; Rooyen, I. J.; Aguiar, J. A.

    2016-11-01

    Precession electron diffraction in the transmission electron microscope was used to map grain orientation and ultimately determine grain boundary misorientation angle distributions, relative fractions of grain boundary types (random high angle, low angle or coincident site lattice (CSL)-related boundaries) and the distributions of CSL-related grain boundaries in the SiC layer of irradiated TRISO-coated fuel particles. Two particles from the AGR-1 experiment exhibiting high Ag-110m retention (>80%) were compared to a particle exhibiting low Ag-110m retention (<19%). Irradiated particles with high Ag-110m retention exhibited a lower fraction of random, high angle grain boundaries compared to the low Ag-110m retention particle. An inverse relationship between the random, high angle grain boundary fraction and Ag-110m retention is found and is consistent with grain boundary percolation theory. Also, comparison of the grain boundary distributions with previously reported unirradiated grain boundary distributions, based on SEM-based EBSD for similarly fabricated particles, showed only small differences, i.e. a greater low angle grain boundary fraction in unirradiated SiC. It was, thus, concluded that SiC layers with grain boundary distributions susceptible to Ag-110m release were present prior to irradiation. Finally, irradiation parameters were found to have little effect on the association of fission product precipitates with specific grain boundary types.

  10. Standard Practice for Measurement of Mechanical Properties During Charged-Particle Irradiation

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1996-01-01

    1.1 This practice covers the performance of mechanical tests on materials being irradiated with charged particles. These tests are designed to simulate or provide understanding of, or both, the mechanical behavior of materials during exposure to neutron irradiation. Practices are described that govern the test material, the particle beam, the experimental technique, and the damage calculations. Reference should be made to other ASTM standards, especially Practice E 521. Procedures are described that are applicable to creep and creep rupture tests made in tension and torsion test modes. 1.2 The word simulation is used here in a broad sense to imply an approximation of the relevant neutron irradiation environment. The degree of conformity can range from poor to nearly exact. The intent is to produce a correspondence between one or more aspects of the neutron and charged particle irradiations such that fundamental relationships are established between irradiation or material parameters and the material respons...

  11. Scanning of irradiated silicon detectors using $\\alpha$ particles and low energy protons

    CERN Document Server

    Casse, G L; Glaser, M; Kohout, Z; Konícek, J; Lemeilleur, F; Leroy, C; Linhart, V; Mares, J J; Pospísil, S; Roy, P; Sopko, B; Sinor, M; Svejda, J; Vorobel, V; Wilhelm, I

    1999-01-01

    In a spectroscopic study of non-irradiated and proton-irradiated silicon diodes, the detectors were illuminated from the front side and from the rear side by various alpha particle sources (mainly ThC') and by monoenergetic protons with energies from 1.0 to 2.5~MeV. Their response characteristics have been studied as a function of the incoming particle energy and the applied bias voltage. The charge collection efficiency was determined as a function of fluence

  12. Effect of ion beam irradiation on metal particle doped polymer ...

    Indian Academy of Sciences (India)

    and converts polymeric structure into hydrogen depleted carbon network. ... Composite materials; ion beam irradiation; dielectric properties; X-ray diffraction. ..... Coat. Technol. 201 8225. Raja V, Sharma A K and Narasimha V V R 2004 Mater.

  13. EPR and UV spectrometry investigation of sucrose irradiated with carbon particles

    International Nuclear Information System (INIS)

    Karakirova, Yordanka; Yordanov, Nicola D.

    2010-01-01

    Solid state/EPR (SS/EPR) dosimeters of carbon ions irradiated sucrose are studied with EPR, and their water solutions - with UV spectroscopy. Doses between 20 and 200 Gy are used with linear energy transfer (LET) values for carbon ions of 63, 77, 96 and 230 keV μm -1 . After irradiation all samples show typical for irradiated sucrose EPR and UV spectra. The obtained data are compared with those previously reported for nitrogen particles and gamma rays irradiated sucrose. The identical shape of both the EPR and UV spectra of irradiated with various type radiation samples suggests that generated free radicals are not influenced by the nature of radiation. The lack of difference in the line width of the separate lines or the whole EPR spectrum, obtained for gamma and heavy particles irradiation, suggests negligible spin-spin interaction among the radiation-generated free radicals in the samples. The linear dependence of the EPR response on the absorbed dose radiation is found to be higher when generated by gamma rays, than by the same absorbed dose of heavy particles. In addition, the EPR response for carbon ions is higher than that for nitrogen ions. Water solutions of irradiated sucrose exhibit UV spectrum with absorption maximum at 267 nm, attributed to the recombination products of free radicals. The UV band intensity depends on the absorbed dose radiation. The UV spectra obtained for carbon, nitrogen and gamma rays irradiated sucrose are also compared.

  14. Antitumor bystander effect induced by radiation-inducible target gene therapy combined with α particle irradiation

    International Nuclear Information System (INIS)

    Liu Hui; Jin Chufeng; Wu Yican; Ge Shenfang; Wu Lijun; FDS Team

    2012-01-01

    In this work, we investigated the bystander effect of the tumor and normal cells surrounding the target region caused by radiation-inducible target gene therapy combined with α-particle irradiation. The receptor tumor cell A549 and normal cell MRC-5 were co-cultured with the donor cells irradiated to 0.5 Gy or the non-irradiated donor cells, and their survival and apoptosis fractions were evaluated. The results showed that the combined treatment of Ad-ET and particle irradiation could induce synergistic antitumor effect on A549 tumor cell, and the survival fraction of receptor cells co-cultured with the irradiated cells decreased by 6%, compared with receptor cells co-cultured with non-irradiated cells, and the apoptosis fraction increased in the same circumstance, but no difference was observed with the normal cells. This study demonstrates that Ad-ET combined with α-particle irradiation can significantly cause the bystander effect on neighboring tumor cells by inhibiting cell growth and inducing apoptosis, without obvious toxicity to normal cells. This suggests that combining radiation-inducible TRAIL gene therapy and irradiation may improve tumor treatment efficacy by specifically targeting tumor cells and even involving the neighboring tumor cells. (authors)

  15. Effects of gamma irradiation and silver nano particles on microbiological characteristics of saffron, using hurdle technology.

    Science.gov (United States)

    Hamid Sales, E; Motamedi Sedeh, F; Rajabifar, S

    2012-03-01

    Saffron, a plant from the Iridaceae family, is the world's most expensive spice. Gamma irradiation and silver nano particles whose uses are gradually increasing worldwide, have positive effects on preventing decay by sterilizing the microorganisms and by improving the safety without compromising the nutritional properties and sensory quality of the foods. In the present study combination effects of gamma irradiation and silver nano particles packaging on the microbial contamination of saffron were considered during storage. A combination of hurdles can ensure stability and microbial safety of foods. For this purpose, saffron samples were packaged by Poly Ethylene films that posses up to 300 ppm nano silver particles as antimicrobial agents and then irradiated in cobalt-60 irradiator (gamma cell PX30, dose rate 0.55 Gry/Sec) to 0, 1, 2,3 and 4 kGy at room temperature. The antimicrobial activities against Total Aerobic Mesophilic Bacteria, Entrobacteriace, Escherichia Coli and Clostridium Perfringines were higher in the irradiated samples, demonstrating the inhibition zone for their growth. Irradiation of the saffron samples packaged by Poly Ethylene films with nano silver particles showed the best results for decreasing microbial contamination at 2 kGy and for Poly Ethylene films without silver nano particles; it was 4 kGy.

  16. Formation of fine solid particles from aqueous solutions of sodium chloropalladate by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Hatada, Motoyoshi; Fujita, Iwao; Korekawa, Kei-ichi.

    1994-10-01

    Studies have been carried out on the radiation chemical formation of palladium fine particles in argon saturated aqueous solutions of sodium chloropalladate without organic stabilizer. The solutions were irradiated with gamma-rays from a cobalt gamma-ray source and the irradiated solutions were subjected to the dynamic light scattering analysis for the particle diameter measurements, and to the UV-visible optical absorption spectroscopy for the measurements of turbidity (absorption at 700 nm) and remaining chloropalladate ion concentrations in the solution. In the solution of pH = 1.95 by HCl, the turbidity increased after the irradiation and then decreased with time. The concentration of remaining palladate ion in the solution decreased by the irradiation, but it gradually increased with time after the irradiation. These phenomena were qualitatively explained by the reaction scheme in that a precursor to the solid particles still exists in the solution after the irradiation was terminated, and that intermediates including the precursor reacted with chloride ion to re-form chloropalladate ions. The average diameter of the particles after the irradiation was ca. 20 nm and it increased with time to 40 nm at 2.75 kGy, and to 80 nm at 8.25 kGy absorption of radiation. The solution of pH = 0.65 by HCl was found to give lower yields of particles than those observed for the solution of pH = 1.95, and to give the particles of diameters about 150-200 nm. In the solution containing HClO 4 instead of HCl, palladium particles were also formed by the irradiation, whereas no backward reaction after the irradiation was observed due to the low concentration of chloride ion in the solution. The average diameter of the particles after the irradiation was about 300 nm and increased with time after the irradiation to a final values which was found to depend on pH of the solution and dose. (author)

  17. Structural transformations in PbSe films irradiated by α-particles

    International Nuclear Information System (INIS)

    Freik, D.M.; Ostapchuk, A.I.; Ogorodnik, Ya.V.; Shkol'nyj, A.K.; Mezhilovskaya, L.I.

    1990-01-01

    Structural changes in PbSe epitaxial layers irradiated by 5 MeV alpha-particles in integral flux of 2x10 12 cm -2 are investigated. It is ascertained that irradiation by alpha-particles can be successfully used as a technological factor dfor directed change of lead selenide properties. Radiation treatment by alpha-particle of epitaxial layers by the doses of ∼ 10 12 cm -2 results in the dispersion of their structure up to polycrystal phase formation. Irradiation by alpha-particles causes donor effect leading to a decrease in hole concentration and to the growth of electronic constituent of conductivity and to the conductivity inversion from p- for n-type

  18. Manakins can produce iridescent and bright feather colours without melanosomes.

    Science.gov (United States)

    Igic, Branislav; D'Alba, Liliana; Shawkey, Matthew D

    2016-06-15

    Males of many species often use colourful and conspicuous ornaments to attract females. Among these, male manakins (family: Pipridae) provide classic examples of sexual selection favouring the evolution of bright and colourful plumage coloration. The highly iridescent feather colours of birds are most commonly produced by the periodic arrangement of melanin-containing organelles (melanosomes) within barbules. Melanin increases the saturation of iridescent colours seen from optimal viewing angles by absorbing back-scattered light; however, this may reduce the wide-angle brightness of these signals, contributing to a dark background appearance. We examined the nanostructure of four manakin species (Lepidothrix isidorei, L. iris, L. nattereri and L. coeruleocapilla) to identify how they produce their bright plumage colours. Feather barbs of all four species were characterized by dense and fibrous internal spongy matrices that likely increase scattering of light within the barb. The iridescent, yet pale or whitish colours of L. iris and L. nattereri feathers were produced not by periodically arranged melanosomes within barbules, but by periodic matrices of air and β-keratin within barbs. Lepidothrix iris crown feathers were able to produce a dazzling display of colours with small shifts in viewing geometry, likely because of a periodic nanostructure, a flattened barb morphology and disorder at a microstructural level. We hypothesize that iridescent plumage ornaments of male L. iris and L. nattereri are under selection to increase brightness or luminance across wide viewing angles, which may potentially increase their detectability by females during dynamic and fast-paced courtship displays in dim light environments. © 2016. Published by The Company of Biologists Ltd.

  19. Cell and tissue kinetics of the subependymal layer in mouse brain following heavy charged particle irradiation

    International Nuclear Information System (INIS)

    Manley, N.B.

    1988-01-01

    The following studies investigate the cellular response and cell population kinetics of the subependymal layer in the mouse brain exposed to heavy charged particle irradiation. Partial brain irradiation with helium and neon ions was confined to one cortex of the brain. Both the irradiated and the unirradiated contralateral cortex showed similar disturbances of the cell and tissue kinetics in the subependymal layers. The irradiated hemisphere exhibited histological damage, whereas the unirradiated side appeared normal histologically. The decrease in the values of the labeling indices 1 week after charged particle irradiation was dose- and ion-dependent. Mitotic indices 1 week after 10 and 25 Gy helium and after 10 Gy neon were the same as those seen in the control mice. Analysis of cell kinetics 1 week after 10 Gy helium and 10 Gy neon irradiation suggests the presence of a progenitor subpopulation that is proliferating with a shorter cell cycle. Comparison of the responses to the different charged particle beams indicates that neon ions are more effective in producing direct cellular damage than the helium ions, but the surviving proliferating cells several divisions later continue to maintain active cell renewal. Based on the 1 week post-irradiation H 3 -TdR labeling indices, a rough estimate of the RBE for neon ions is at least 2.5 when compared to helium ions

  20. PIE on Safety-Tested Loose Particles from Irradiated Compact 4-4-2

    Energy Technology Data Exchange (ETDEWEB)

    Hunn, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gerczak, Tyler J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Morris, Robert Noel [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Baldwin, Charles A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Montgomery, Fred C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-04-01

    Post-irradiation examination (PIE) is being performed in support of tristructural isotropic (TRISO) coated particle fuel development and qualification for High Temperature Gas-cooled Reactors (HTGRs). This work is sponsored by the Department of Energy Office of Nuclear Energy (DOE-NE) through the Advanced Reactor Technologies (ART) Office under the Advanced Gas Reactor Fuel Development and Qualification (AGR) Program. The AGR-1 experiment was the first in a series of TRISO fuel irradiation tests initiated in 2006. The AGR-1 TRISO particles and fuel compacts were fabricated at Oak Ridge National Laboratory (ORNL) in 2006 using laboratory-scale equipment and irradiated for 3 years in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) to demonstrate and evaluate fuel performance under HTGR irradiation conditions. Post-irradiation examination was performed at INL and ORNL to study how the fuel behaved during irradiation, and to test fuel performance during exposure to elevated temperatures at or above temperatures that could occur during a depressurized conduction cooldown event. This report summarizes safety testing and post-safety testing PIE conducted at ORNL on loose particles extracted from irradiated AGR-1 Compact 4-4-2.

  1. Role of Rab family GTPases and their effectors in melanosomal logistics.

    Science.gov (United States)

    Ohbayashi, Norihiko; Fukuda, Mitsunori

    2012-04-01

    Rab GTPases constitute a family of small GTPases that regulate a variety of membrane trafficking events in all eukaryotic cells by recruiting their specific effector molecules. Recent accumulating evidence indicates that members of the mammalian Rab small GTPase family are involved in certain physiological and pathological processes. In particular, functional impairments of specific Rab proteins, e.g. Rab38 and Rab27A, their regulators or their effectors cause pigmentation disorders in humans and coat colour variations in mice because such impairments cause defects in melanosomal logistics, i.e. defects in melanosome biogenesis and transport. Genetic and biochemical analyses of the gene products responsible for mammalian pigmentation disorders in the past decade have revealed that Rab-mediated endosomal transport systems and melanosome transport systems play crucial roles in the efficient darkening of mammalian hair and skin. In this article, we review current knowledge regarding melanosomal logistics, with particular focus on the roles of Rab small GTPases and their effectors.

  2. Manual for target thickness measurement by alpha particle irradiation

    International Nuclear Information System (INIS)

    Dias, J.F.; Martins, M.N.

    1990-04-01

    A system is described for thin-target thickness measurement through the alpha particle energy loss when them traverse the target. It is also described the program used in the analysis of the target thickness. (L.C.) [pt

  3. Impact of electron irradiation on particle track etching response in ...

    Indian Academy of Sciences (India)

    energy by an ionizing particle traversing a material medium. When the ... Their amorphous nature and radiation sensitivity further ... The samples were washed thoroughly in lukewarm soap solution to avoid non-uniformity in etching due to ...

  4. Measurement of kernel swelling and buffer densification in irradiated UCO-TRISO particles

    Energy Technology Data Exchange (ETDEWEB)

    Bower, Gordon R., E-mail: bowegr@inl.gov [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID, 83415-6188 (United States); Ploger, Scott A.; Demkowicz, Paul A. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID, 83415-6188 (United States); Hunn, John D. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN, 37830-6093 (United States)

    2017-04-01

    Radiation-induced volume changes in the fuel kernels and buffer layers of UCO-TRISO particles irradiated to an average burnup of 16.1% FIMA have been determined. Measurements of particle dimensions were made on polished cross-sections of 56 irradiated particles at several different polish planes. The data were then analyzed to compute the equivalent spherical diameters of the kernels and the various coating layers, and these were compared to the average as-fabricated values to determine changes due to irradiation. The kernel volume was found to have increased by an average of 26 ± 6%. Buffer volume decreased by an average of 39 ± 2% due to densification.

  5. Proton permeability of membranes of Streptococcus faecalis and submitochondrial particles of rats after irradiation

    International Nuclear Information System (INIS)

    Fomenko, B.S.; Pinchukova, V.A.

    1977-01-01

    It has been shown that at a changed, by HCl impulse, pH of Streptococcus faecalis suspension and submitochondrial liver particles (SLP) of rats, H + concentration decreases more rapidly in the irradiated bacteria and SLP than in the controls. The curves of energy dependence of accumulation of the penetrating ions were also displaced toward the alkaline zone depending on pH. These effects are suggested to be connected with an increased proton permeability of irradiated membranes

  6. Cell and tissue kinetics of the subependymal layer in mouse brain following heavy charged particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Manley, N.B.; Fabrikant, J.I.; Alpen, E.L.

    1988-12-01

    The following studies investigate the cellular response and cell population kinetics of the subependymal layer in the mouse brain exposed to heavy charged particle irradiation. Partial brain irradiation with helium and neon ions was confined to one cortex of the brain. Both the irradiated and the unirradiated contralateral cortex showed similar disturbances of the cell and tissue kinetics in the subependymal layers. The irradiated hemisphere exhibited histological damage, whereas the unirradiated side appeared normal histologically. This study concerns the cell population and cell cycle kinetics of the subependymal layer in the mouse brain, and the effects of charged particle irradiations on this cell population. Quantitative high resolution autoradiography was used to study the kinetic parameters in this cell layer. This study should help in understanding the effects of these high-energy heavy ions on normal mammalian brain tissue. The response of the mammalian brain exposure to charged particle ionizing radiation may be extremely variable. It varies from minimal physiological changes to overt tissue necrosis depending on a number of factors such as: the administered dose, dose-rate, the volume of the irradiated tissue, and the biological end-point being examined.

  7. Radiosensitivity of Prostate Cancer Cell Lines for Irradiation from Beta Particle-emitting Radionuclide ¹⁷⁷Lu Compared to Alpha Particles and Gamma Rays.

    Science.gov (United States)

    Elgqvist, Jörgen; Timmermand, Oskar Vilhelmsson; Larsson, Erik; Strand, Sven-Erik

    2016-01-01

    The purpose of the present study was to investigate the radiosensitivity of the prostate cancer cell lines LNCaP, DU145, and PC3 when irradiated with beta particles emitted from (177)Lu, and to compare the effect with irradiation using alpha particles or gamma rays. Cells were irradiated with beta particles emitted from (177)Lu, alpha particles from (241)Am, or gamma rays from (137)Cs. A non-specific polyclonal antibody was labeled with (177)Lu and used to irradiate cells in suspension with beta particles. A previously described in-house developed alpha-particle irradiator based on a (241)Am source was used to irradiate cells with alpha particles. External gamma-ray irradiation was achieved using a standard (137)Cs irradiator. Cells were irradiated to absorbed doses equal to 0, 0.5, 1, 2, 4, 6, 8, or 10 Gy. The absorbed doses were calculated as mean absorbed doses. For evaluation of cell survival, the tetrazolium-based WST-1 assay was used. After irradiation, WST-1 was added to the cell solutions, incubated, and then measured for level of absorbance at 450 nm, indicating the live and viable cells. LNCaP, DU145, and PC3 cell lines all had similar patterns of survival for the different radiation types. No significant difference in surviving fractions were observed between cells treated with beta-particle and gamma-ray irradiation, represented for example by the surviving fraction values (mean±SD) at 2, 6, and 10 Gy (SF2, SF6, and SF10) for DU145 after beta-particle irradiation: 0.700±0.090, 0.186±0.050 and 0.056±0.010, respectively. A strong radiosensitivity to alpha particles was observed, with SF2 values of 0.048±0.008, 0.018±0.006 and 0.015±0.005 for LNCaP, DU145, and PC3, respectively. The surviving fractions after irradiation using beta particles or gamma rays did not differ significantly at the absorbed dose levels and dose rates used. Irradiation using alpha particles led to a high level of cell killing. The results show that the beta-particle emitter

  8. Influence of catechins on bystander responses in CHO cells induced by alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Law, Y.L.; Wong, T.P.W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)], E-mail: peter.yu@cityu.edu.hk

    2010-04-15

    In this work, we studied alpha-particle induced and medium-mediated bystander effects in Chinese hamster ovary (CHO) cells through micronucleus (MN) assay. We showed that signal transduction from irradiated cells to bystander cells occur within a short time after irradiation. We then studied the effects of ROS (reactive oxygen species)-scavenging catechins in the medium before irradiation. We observed decreases in the percentage of bystander cells with MN formation and thus proved the protection effect of catechins on bystander cells from radiation.

  9. Performance evaluation of large U-Mo particle dispersed fuel irradiated in HANARO

    International Nuclear Information System (INIS)

    Ryu, Ho Jin; Park, Jong Man; Oh, Seok Jin; Jang, Se Jung; Yu, Byung Ok; Lee, Choong Seong; Seo, Chul Gyo; Chae, Hee Taek; Kim, Chang Kyu

    2008-01-01

    U-Mo/Al dispersion fuel is being developed as advanced fuel for research reactors. Irradiation behavior of U-Mo/Al dispersion fuel has been studied to evaluate its fuel performance. One of the performance limiting factors is a chemical interaction between the U-Mo particle and the Al matrix because the thermal conductivity of fuel meat is decreased with the interaction layer growth. In order to overcome the interaction problem, large-sized U-Mo particles were fabricated by controlling the centrifugal atomization conditions. The fuel performance behavior of U-Mo/Al dispersion fuel was estimated by using empirical models formulated based on the microstructural analyses of the post-irradiation examination (PIE) on U-Mo/Al dispersion fuel irradiated in HANARO reactor. Temperature histories of U-Mo/Al dispersion fuel during irradiation tests were estimated by considering the effect of an interaction layer growth on the thermal conductivity of the fuel meat. When the fuel performances of the dispersion fuel rods containing U-Mo particles with various sizes were compared, fuel temperature was decreased as the average U-Mo particle size was increases. It was found that the dispersion of a larger U-Mo particle was effective for mitigating the thermal degradation which is associated with an interaction layer growth. (author)

  10. Cell survival following alpha particle irradiation: critical sites and implications for carcinogenesis

    International Nuclear Information System (INIS)

    Lloyd, E.L.; Gemmell, M.A.; Henning, C.B.; Gemmell, D.S.; Zabransky, B.J.

    1976-01-01

    In experiments in which mammalian cells were irradiated with 5.6 MeV alpha particles from a Tandem Van de Graaff machine we have confirmed the finding of others that the mean lethal dose (D 0 ) is about 100 rad, but by measurements of the area of the cell nuclei as irradiated we found that this mean lethal dose corresponds not to 1, as expected, but to about 27 alpha particles per cell nucleus. (The exact number appears to change slightly with cell passage number.) This allows for the possibility that the direct action of alpha particles on the nucleus may be the important event in carcinogenesis, a theory which was previously difficult to accept if a single particle hitting the nucleus anywhere was considered to be lethal. Evidence is presented to implicate the nucleolus as a possible critical site for the inhibition of reproductive integrity of the cell

  11. Elevated sodium chloride concentrations enhance the bystander effects induced by low dose alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Han Wei; Zhu Lingyan; Jiang Erkang; Wang Jun; Chen Shaopeng; Bao Linzhi; Zhao Ye; Xu An; Yu Zengliang [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Wu Lijun [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)], E-mail: ljw@ipp.ac.cn

    2007-11-01

    Previous studies have shown that high NaCl can be genotoxic, either alone or combined with irradiation. However, little is known about the relationship between environmental NaCl at elevated conditions and radiation-induced bystander effects (RIBE). RIBE, which has been considered as non-targeted bystander responses, has been demonstrated to occur widely in various cell lines. In the present study, RIBE under the elevated NaCl culture condition was assessed in AG 1522 cells by both the induction of {gamma}-H2AX, a reliable marker of DNA double-strand break (DSB) for the early process (<1 h post irradiation), and the generation of micronuclei (MN), a sensitive marker for relative long process of RIBE. Our results showed that in the absence of irradiation, NaCl at elevated concentration such as 8.0, 9.0 and 10.0 g/L did not significantly increase the frequency of {gamma}-H2AX foci-positive cells and the number of foci per positive cell comparing with that NaCl at a normal concentration (6.8 g/L). However, with 0.2 cGy {alpha}-particle irradiation, the induced fraction of {gamma}-H2AX foci-positive cells and the number of induced {gamma}-H2AX foci per positive cell were significantly increased in both irradiated and adjacent non-irradiated regions. Similarly, the induction of MN by 0.2 cGy {alpha}-particle irradiation also increased with the elevated NaCl concentrations. With N{sup G}-methyl-L-arginine, an inhibitor of nitric oxide synthase, the induced fraction of foci-positive cells was effectively inhibited both in 0.2 cGy {alpha}-particle irradiated and adjacent non-irradiated regions under either normal or elevated NaCl conditions. These results suggested that the cultures with elevated NaCl medium magnified the damage effects induced by the low dose {alpha}-particle irradiation and nitric oxide generated by irradiation was also very important in this process.

  12. Deoxyarbutin Possesses a Potent Skin-Lightening Capacity with No Discernible Cytotoxicity against Melanosomes.

    Directory of Open Access Journals (Sweden)

    Fang Miao

    Full Text Available Safe and effective ingredients capable of removing undesired hyperpigmentation from facial skin are urgently needed for both pharmaceutical and cosmetic purposes. Deoxyarbutin (4-[(tetrahydro-2H-pyran-2-yl oxy] phenol, D-Arb is a glucoside derivative of hydroquinone. Here, we investigated the toxicity and efficacy of D-Arb at the sub-cellular level (directly on melanosomes and skin pigmentation using in vivo and in vitro models to compare with its parent compound hydroquinone (1,4-benzenediol, HQ. At first, we examined the ultrastructural changes of melanosomes in hyperpigmented guinea pig skin induced by 308-nm monochromatic excimer lightand/or treated with HQ and D-Arb using transmission electron microscopy. The results showed that prominent changes in the melanosomal membrane, such as bulb-like structure and even complete rupture of the outer membranes, were found in the skin after topical application of 5% HQ for 10 days. These changes were barely observed in the skin treated with D-Arb. To further clarify whether membrane toxicity of HQ was a direct result of the compound treatment, we also examinedultrastructural changes of individual melanosomes purified from MNT1 human melanoma cells. Similar observations were obtained from the naked melanosome model in vitro. Finally, we determined the effects of melanosomal fractions exposed to HQ or D-Arb on hydroxyl radical generation in the Fenton reaction utilizing an electron spin resonance assay. D-Arb-treated melanosomesexhibit a moderate hydroxyl radical-scavenging activity, whereas HQ-treated melanosomessignificantly generate more hydroxyl free radicals. This study suggests that D-Arb possesses a potent ability in skin lightening and antioxidation with less melanosome cytotoxicity.

  13. Deoxyarbutin Possesses a Potent Skin-Lightening Capacity with No Discernible Cytotoxicity against Melanosomes.

    Science.gov (United States)

    Miao, Fang; Shi, Ying; Fan, Zhi-Feng; Jiang, Shan; Xu, Shi-Zheng; Lei, Tie-Chi

    2016-01-01

    Safe and effective ingredients capable of removing undesired hyperpigmentation from facial skin are urgently needed for both pharmaceutical and cosmetic purposes. Deoxyarbutin (4-[(tetrahydro-2H-pyran-2-yl) oxy] phenol, D-Arb) is a glucoside derivative of hydroquinone. Here, we investigated the toxicity and efficacy of D-Arb at the sub-cellular level (directly on melanosomes) and skin pigmentation using in vivo and in vitro models to compare with its parent compound hydroquinone (1,4-benzenediol, HQ). At first, we examined the ultrastructural changes of melanosomes in hyperpigmented guinea pig skin induced by 308-nm monochromatic excimer lightand/or treated with HQ and D-Arb using transmission electron microscopy. The results showed that prominent changes in the melanosomal membrane, such as bulb-like structure and even complete rupture of the outer membranes, were found in the skin after topical application of 5% HQ for 10 days. These changes were barely observed in the skin treated with D-Arb. To further clarify whether membrane toxicity of HQ was a direct result of the compound treatment, we also examinedultrastructural changes of individual melanosomes purified from MNT1 human melanoma cells. Similar observations were obtained from the naked melanosome model in vitro. Finally, we determined the effects of melanosomal fractions exposed to HQ or D-Arb on hydroxyl radical generation in the Fenton reaction utilizing an electron spin resonance assay. D-Arb-treated melanosomesexhibit a moderate hydroxyl radical-scavenging activity, whereas HQ-treated melanosomessignificantly generate more hydroxyl free radicals. This study suggests that D-Arb possesses a potent ability in skin lightening and antioxidation with less melanosome cytotoxicity.

  14. Attempts of local irradiation of cells by microbeam. From ultraviolet to heavy particles

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Yasuhiko [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2002-03-01

    This review describes the history of attempts of local irradiation of cells by microbeam and present status of the study. Local irradiation of cells was attempted as early as in 1912 with use of short {alpha}-particle range and of focused UV beams. After the war, laser microbeams were then developed for microsurgery in embryology. In addition, microbeams of electron generated from the gun and of X-ray collimated were developed. In 1950s, the electron microbeam was generated from Van de Graaff accelerator in Chicago University and proton, deuteron and He-ion microbeams from the cyclotron, in BNL. In 1980s, Gesellschaft fuer Schwerionenforshung (Germany) used heavy ion microbeams from C to U generated from the linear accelerator and PNL, proton to {sup 4}He-ion microbeams from the tandem-electrostatic accelerator. At present in 2002, the equipments for microbeam for cell irradiation are the Van de Graaff accelerators in Gray Cancer Institute (England) and in Columbia University, and the cyclotron in TIARA in Japan. The purpose of the study in TIARA is to develop a system to generate heavy particle microbeams for cell irradiation for analysis of the biological effect of ultra-low fluence, high LET heavy particles like the galactic cosmic ray. Recently, the CHO-KI cell nucleus is irradiated by {sup 40}Ar and {sup 20}Ne ions. (K.H.)

  15. Attempts of local irradiation of cells by microbeam. From ultraviolet to heavy particles

    International Nuclear Information System (INIS)

    Kobayashi, Yasuhiko

    2002-01-01

    This review describes the history of attempts of local irradiation of cells by microbeam and present status of the study. Local irradiation of cells was attempted as early as in 1912 with use of short α-particle range and of focused UV beams. After the war, laser microbeams were then developed for microsurgery in embryology. In addition, microbeams of electron generated from the gun and of X-ray collimated were developed. In 1950s, the electron microbeam was generated from Van de Graaff accelerator in Chicago University and proton, deuteron and He-ion microbeams from the cyclotron, in BNL. In 1980s, Gesellschaft fuer Schwerionenforshung (Germany) used heavy ion microbeams from C to U generated from the linear accelerator and PNL, proton to 4 He-ion microbeams from the tandem-electrostatic accelerator. At present in 2002, the equipments for microbeam for cell irradiation are the Van de Graaff accelerators in Gray Cancer Institute (England) and in Columbia University, and the cyclotron in TIARA in Japan. The purpose of the study in TIARA is to develop a system to generate heavy particle microbeams for cell irradiation for analysis of the biological effect of ultra-low fluence, high LET heavy particles like the galactic cosmic ray. Recently, the CHO-KI cell nucleus is irradiated by 40 Ar and 20 Ne ions. (K.H.)

  16. Improvement of Electrical Conductivity of Single-Walled Carbon Nano tube Network Using Particle Irradiation

    International Nuclear Information System (INIS)

    Lim, Suntaek; Kim, Gonho

    2010-01-01

    Substitution for Indium Tin Oxide of transparent electrode Applications : Flat panel displays, Touch panel, Solar cell, EM wave shielding... For very low energy of 20 eV and 90 eV, argon ion irradiations, the surface of SWCNT bundles were sputtered and thinned the diameter of the bundle. With increasing the incident ion energy as 7.5 keV, SWCNT bundles were networked by amorphization of cross welded CNTs. → Less damage can be obtained from higher energy of irradiated particle due to less collision cross section. For 10 MeV proton and 800 keV electron irradiations, there are no severe damages. Electron irradiation is more effective on network with less damage than that of ion irradiation. → Network process can be proceeded with the generation of free carbon, the migration of free carbon on CNT and reconstruction of the cross linked CNTs, which processes require the latent energy on CNT body after collision. It can be controlled by the energy and dose of irradiation particle

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

    International Nuclear Information System (INIS)

    Ishino, S.; Sekimura, N.

    1990-01-01

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

  18. Irradiation performance of HTGR Biso fertile particles in HFIR experiments HT-17, -18, and -19

    International Nuclear Information System (INIS)

    Long, E.L. Jr.; Beatty, R.L.; Robbins, J.M.; Kania, M.J.; Eatherly, W.P.

    1978-11-01

    A series of Biso-coated fertile particles was irradiated in the target facility of the High-Flux Isotope Reactor. The primary objectives of this experiment were to relate the fast-neutron stability of dense propylene-derived pyrocarbons to preferred orientation and to relate irradiation performance to preirradiation characterization values. Coating characterization included x-ray BAF, optical anisotropy, gaseous permeability, small-angle x-ray scattering, and thickness and density determinations. Other objectives were to test Biso-coated large-diameter ThO 2 kernels and coatings derived from propylene diluted with CO 2 rather than argon. Visual examination of the irradiated particles showed that the majority had failed as a result of fast-neutron damage

  19. Influence of penetration controlled irradiation with charged particles on tobacco pollen

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Hiroshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Dept. of Radiation Research for Environment and Resources; Tanaka, Atsushi; Tano, Shigemitsu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Advanced Science Research Center; Inoue, Masayoshi [Kyoto Prefectural Univ. (Japan). Faculty of Agriculture

    1997-09-01

    To investigate the effect of local irradiation on biological systems, an apparatus for penetration controlled irradiation with charged particles was set up. By comparison of ranges of 1.5 MeV/u He{sup 2+} between the theoretically calculated ranges and the practical ranges using RCD dosimeter, it was demonstrated that the range of particles could be controlled linearly by changing the distance from the beam window in the atmosphere to a target. In addition, the penetration controlled irradiation of tobacco pollen increased the frequency of `leaky pollen`. The increased frequency of the leaky pollen suggests that a damage in the pollen envelope would be induced at the range-end. (orig.)

  20. A model of knock-out of oxygen by charged particle irradiation of Bi-2212

    International Nuclear Information System (INIS)

    Bandyopadhyay, S.K.; Sen, Pintu; Barat, P.; Mukherjee, P.; Das, S.K.; Ghosh, B.

    1996-01-01

    A model of knock-out of oxygen by charged particle (α and proton) irradiation of Bi 2 Sr 2 CaCu 2 O 8+x (Bi-2212) is proposed on the basis of Monte Carlo TRIM calculations. In Bi-2212, the loosely bound excess oxygen is vulnerable to be displaced by particle irradiation. Binding energy and hence, displacement energy of this loosely bound excess oxygen is less compared to that of stoichiometric lattice bound oxygen and other atoms. The displaced or knocked out oxygen goes to pores or intergranular region and generates large pressure inside the sample. Because of porosity of the material, this displaced oxygen diffuses out and there is a net reduction of oxygen content of the sample. The irradiation induced oxygen knock-out is dominant in the bulk where nonionizing energy loss is maximum. (author). 29 refs., 1 fig., 3 tabs

  1. Fossilized melanosomes and the colour of Cretaceous dinosaurs and birds.

    Science.gov (United States)

    Zhang, Fucheng; Kearns, Stuart L; Orr, Patrick J; Benton, Michael J; Zhou, Zhonghe; Johnson, Diane; Xu, Xing; Wang, Xiaolin

    2010-02-25

    Spectacular fossils from the Early Cretaceous Jehol Group of northeastern China have greatly expanded our knowledge of the diversity and palaeobiology of dinosaurs and early birds, and contributed to our understanding of the origin of birds, of flight, and of feathers. Pennaceous (vaned) feathers and integumentary filaments are preserved in birds and non-avian theropod dinosaurs, but little is known of their microstructure. Here we report that melanosomes (colour-bearing organelles) are not only preserved in the pennaceous feathers of early birds, but also in an identical manner in integumentary filaments of non-avian dinosaurs, thus refuting recent claims that the filaments are partially decayed dermal collagen fibres. Examples of both eumelanosomes and phaeomelanosomes have been identified, and they are often preserved in life position within the structure of partially degraded feathers and filaments. Furthermore, the data here provide empirical evidence for reconstructing the colours and colour patterning of these extinct birds and theropod dinosaurs: for example, the dark-coloured stripes on the tail of the theropod dinosaur Sinosauropteryx can reasonably be inferred to have exhibited chestnut to reddish-brown tones.

  2. Survival of Acholeplasma laidlawii, strain S2 after irradiation with alpha particles of /sup 241/Americium

    Energy Technology Data Exchange (ETDEWEB)

    Liska, B.; Drasil, V.; Brza, I. (Ceskoslovenska Akademie Ved, Brno. Biofysikalni Ustav)

    1985-05-23

    A thin layer of dry Acholeplasma laidlawii, strain S2 cells was irradiated with /sup 241/Am alpha particles. D/sub 0/ was 2.54 x 10/sup 7/ - 2.63 x 10/sup 7/ alpha particles/mm/sup 2/ (48 - 50 minutes, 409 - 422 Gy). The extrapolation number was 1.05 - 3.1. The effective cross section at D/sub 0/ was 0.038 - 0.039 ..mu..m/sup 2//alpha particle. A method of preparing thin dry layers of Acholeplasma cells was developed.

  3. Effects of heavy particle irradiation and diet on object recognition memory in rats

    Science.gov (United States)

    Rabin, Bernard M.; Carrihill-Knoll, Kirsty; Hinchman, Marie; Shukitt-Hale, Barbara; Joseph, James A.; Foster, Brian C.

    2009-04-01

    On long-duration missions to other planets astronauts will be exposed to types and doses of radiation that are not experienced in low earth orbit. Previous research using a ground-based model for exposure to cosmic rays has shown that exposure to heavy particles, such as 56Fe, disrupts spatial learning and memory measured using the Morris water maze. Maintaining rats on diets containing antioxidant phytochemicals for 2 weeks prior to irradiation ameliorated this deficit. The present experiments were designed to determine: (1) the generality of the particle-induced disruption of memory by examining the effects of exposure to 56Fe particles on object recognition memory; and (2) whether maintaining rats on these antioxidant diets for 2 weeks prior to irradiation would also ameliorate any potential deficit. The results showed that exposure to low doses of 56Fe particles does disrupt recognition memory and that maintaining rats on antioxidant diets containing blueberry and strawberry extract for only 2 weeks was effective in ameliorating the disruptive effects of irradiation. The results are discussed in terms of the mechanisms by which exposure to these particles may produce effects on neurocognitive performance.

  4. Molecular evidence of keratin and melanosomes in feathers of the Early Cretaceous bird Eoconfuciusornis.

    Science.gov (United States)

    Pan, Yanhong; Zheng, Wenxia; Moyer, Alison E; O'Connor, Jingmai K; Wang, Min; Zheng, Xiaoting; Wang, Xiaoli; Schroeter, Elena R; Zhou, Zhonghe; Schweitzer, Mary H

    2016-12-06

    Microbodies associated with feathers of both nonavian dinosaurs and early birds were first identified as bacteria but have been reinterpreted as melanosomes. Whereas melanosomes in modern feathers are always surrounded by and embedded in keratin, melanosomes embedded in keratin in fossils has not been demonstrated. Here we provide multiple independent molecular analyses of both microbodies and the associated matrix recovered from feathers of a new specimen of the basal bird Eoconfuciusornis from the Early Cretaceous Jehol Biota of China. Our work represents the oldest ultrastructural and immunological recognition of avian beta-keratin from an Early Cretaceous (∼130-Ma) bird. We apply immunogold to identify protein epitopes at high resolution, by localizing antibody-antigen complexes to specific fossil ultrastructures. Retention of original keratinous proteins in the matrix surrounding electron-opaque microbodies supports their assignment as melanosomes and adds to the criteria employable to distinguish melanosomes from microbial bodies. Our work sheds new light on molecular preservation within normally labile tissues preserved in fossils.

  5. Fission product Pd-SiC interaction in irradiated coated particle fuels

    International Nuclear Information System (INIS)

    Tiegs, T.N.

    1980-04-01

    Silicon carbide is the main barrier to fission product release from coated particle fuels. Consequently, degradation of the SiC must be minimized. Electron microprobe analysis has identified that palladium causes corrosion of the SiC in irradiated coated particles. Further ceramographic and electron microprobe examinations on irradiated particles with kernels ranging in composition from UO 2 to UC 2 , including PuO/sub 2 -x/ and mixed (Th, Pu) oxides, and in enrichment from 0.7 to 93.0% 235 U revealed that temperature is the major factor affecting the penetration rate of SiC by Pd. The effects of kernel composition, Pd concentration, other fission products, and SiC properties are secondary

  6. Improvement of a method for predicting failure rates of coated particles during irradiation

    International Nuclear Information System (INIS)

    Bongartz, K.

    1977-01-01

    A method for calculating the coating stress distribution resulting from the statistical spread of geometrical parameters in irradiated fuel particle batches has been developed by Gulden et al. The existing method utilizing coated particles is extended in two ways: 1. A more realistic treatment of the buffer layer is adopted, taking into account its physical properties. 2. A statistical distribution according to Weibull has been adopted for the silicon carbide layer strength. Calculations with both the new and the old assumptions were performed on one feed particle and one breed particle type. It is shown that the two modifications influence the results of the original method. It was found that the extension of the first assumption has no influence on the stress distribution and the fraction of breaking feed particles, but it changes the stress distribution of the breed particles significantly. The fraction of broken particles at end burnup is increased by a factor of approximately 10. The extension of the second assumption affects the fraction of broken feed as well as that of the breed particles. Depending on the Weibull parameter, m, the number of failed feed particles increases by a factor of 1.3 to 2; the corresponding factor for breed particles is between 3.5 and 60

  7. Irradiated-Microsphere Gamma Analyzer (IMGA): an integrated system for HTGR coated particle fuel performance assessment

    International Nuclear Information System (INIS)

    Kania, M.J.; Valentine, K.H.

    1980-02-01

    The Irradiated-Microsphere Gamma Analyzer (IMGA) System, designed and built at ORNL, provides the capability of making statistically accurate failure fraction measurements on irradiated HTGR coated particle fuel. The IMGA records the gamma-ray energy spectra from fuel particles and performs quantitative analyses on these spectra; then, using chemical and physical properties of the gamma emitters it makes a failed-nonfailed decision concerning the ability of the coatings to retain fission products. Actual retention characteristics for the coatings are determined by measuring activity ratios for certain gamma emitters such as 137 Cs/ 95 Zr and 144 Ce/ 95 Zr for metallic fission product retention and 134 Cs/ 137 Cs for an indirect measure of gaseous fission product retention. Data from IMGA (which can be put in the form of n failures observed in N examinations) can be accurately described by the binomial probability distribution model. Using this model, a mathematical relationship between IMGA data (n,N), failure fraction, and confidence level was developed. To determine failure fractions of less than or equal to 1% at confidence levels near 95%, this model dictates that from several hundred to several thousand particles must be examined. The automated particle handler of the IMGA system provides this capability. As a demonstration of failure fraction determination, fuel rod C-3-1 from the OF-2 irradiation capsule was analyzed and failure fraction statistics were applied. Results showed that at the 1% failure fraction level, with a 95% confidence level, the fissile particle batch could not meet requirements; however, the fertile particle exceeded these requirements for the given irradiation temperature and burnup

  8. Laser pulse heating of steel mixing with WC particles in a irradiated region

    Science.gov (United States)

    Shuja, S. Z.; Yilbas, B. S.; Ali, H.; Karatas, C.

    2016-12-01

    Laser pulse heating of steel mixing with tungsten carbide (WC) particles is carried out. Temperature field in the irradiated region is simulated in line with the experimental conditions. In the analysis, a laser pulse parameter is introduced, which defines the laser pulse intensity distribution at the irradiated surface. The influence of the laser parameter on the melt pool size and the maximum temperature increase in the irradiated region is examined. Surface temperature predictions are compared with the experimental data. In addition, the distribution of WC particles and their re-locations in the treated layer, due to combination of the natural convection and Marangoni currents, are predicted. The findings are compared to the experimental data. It is found that surface temperature predictions agree well with the experimental data. The dislocated WC particles form a streamlining in the near region of the melt pool wall, which agree with the experimental findings. The Gaussian distribution of the laser pulse intensity results in the maximum peak temperature and the maximum flow velocity inside the melt pool. In this case, the melt pool depth becomes the largest as compared to those corresponding to other laser pulse intensity distributions at the irradiated surface.

  9. Elevated sodium chloride concentrations enhance the bystander effects induced by low dose alpha-particle irradiation

    International Nuclear Information System (INIS)

    Han Wei; Zhu Lingyan; Jiang Erkang; Wang Jun; Chen Shaopeng; Bao Linzhi; Zhao Ye; Xu An; Yu Zengliang; Wu Lijun

    2007-01-01

    Previous studies have shown that high NaCl can be genotoxic, either alone or combined with irradiation. However, little is known about the relationship between environmental NaCl at elevated conditions and radiation-induced bystander effects (RIBE). RIBE, which has been considered as non-targeted bystander responses, has been demonstrated to occur widely in various cell lines. In the present study, RIBE under the elevated NaCl culture condition was assessed in AG 1522 cells by both the induction of γ-H2AX, a reliable marker of DNA double-strand break (DSB) for the early process ( G -methyl-L-arginine, an inhibitor of nitric oxide synthase, the induced fraction of foci-positive cells was effectively inhibited both in 0.2 cGy α-particle irradiated and adjacent non-irradiated regions under either normal or elevated NaCl conditions. These results suggested that the cultures with elevated NaCl medium magnified the damage effects induced by the low dose α-particle irradiation and nitric oxide generated by irradiation was also very important in this process

  10. Accelerator-Based Irradiation Creep of Pyrolytic Carbon Used in TRISO Fuel Particles for the (VHTR) Very High Temperature Reactors

    International Nuclear Information System (INIS)

    Wang, Lumin; Was, Gary

    2010-01-01

    Pyrolytic carbon (PyC) is one of the important structural materials in the TRISO fuel particles which will be used in the next generation of gas-cooled very-high-temperature reactors (VHTR). When the TRISO particles are under irradiation at high temperatures, creep of the PyC layers may cause radial cracking leading to catastrophic particle failure. Therefore, a fundamental understanding of the creep behavior of PyC during irradiation is required to predict the overall fuel performance.

  11. Luminescence yield in irradiating gases by X-rays and alpha particles

    International Nuclear Information System (INIS)

    Combecher, D.

    1973-01-01

    In this paper, the measurable light emission in the irradiation of gases as modle substances has been quantitatively determined. The gases Ar, H 2 , N 2 , air, and C 3 H 8 were irradiated with X-rays and α-particles at a pressure of 730 torr. The emitted light was measured in the spectral range between the short-wave absorption edge of the gases and 6000 A (spectral resolution: 20 A). The spectral light yield was determined from the efficiency of the apparatus and from the total energy absorbed in the gases. (HK) [de

  12. Ebselen is a new skin depigmenting agent that inhibits melanin biosynthesis and melanosomal transfer.

    Science.gov (United States)

    Kasraee, Behrooz; Nikolic, Damjan S; Salomon, Denis; Carraux, Pierre; Fontao, Lionel; Piguet, Vincent; Omrani, Gholamhossein R; Sorg, Olivier; Saurat, Jean-Hilaire

    2012-01-01

    We assessed the ability of ebselen, a glutathione peroxidase mimic, to reduce pigmentation in various models. In murine B16 melanocytes, 25 μm ebselen inhibited melanogenesis and induced a depolymerisation of actin filaments. In co-cultures of B16 melanocytes with BDVII keratinocytes, a pretreatment of melanocytes with ebselen resulted in a strong inhibition of melanosome transfer to keratinocytes, as shown under optical and electron microscopy. In reconstructed epidermis, topical 0.5% ebselen led to a twofold decrease of melanin without affecting the density of active melanocytes. A similar result was obtained with topical 0.5% ebselen in black guinea pig ears. Ebselen induced a decrease of epidermal melanin parallel to a localisation of melanin and melanosomes in the basal layer. Ebselen appears as a new depigmenting compound that inhibits melanin synthesis and melanosome transfer to keratinocytes. © 2011 John Wiley & Sons A/S.

  13. Irradiation test OF-2: high-temperature irradiation behavior of LASL-made fuel rods and LASL-made coated particles

    International Nuclear Information System (INIS)

    Wagner, P.; Reiswig, R.D.; Hollabaugh, C.M.; White, R.W.; O'Rourke, J.A.; Davidson, K.V.; Schell, D.H.

    1977-10-01

    Three LASL-made, substoichiometric ZrC-coated particles with inert kernels, and two high-density molded graphite fuel rods that contained LASL-made, ZrC-coated fissile particles were irradiated in the Oak Ridge Research Reactor test OF-2. The severest test conditions were 8.36 x 10 21 nvt (E greater than 0.18 MeV) at 1350 0 C. The graphite matrix showed no effect of the irradiation. There was no interaction between the matrix and any of the particle coats. The loose ZrC coated particles with inert kernels showed no irradiation effects. The graded ZrC-C coats on the fissile particles were cracked. It is postulated that the cracking is associated with the low LTI deposition rate and is not related to the ZrC

  14. The effects of heavy particle irradiation on exploration and response to environmental change

    Science.gov (United States)

    Casadesus, G.; Shukitt-Hale, B.; Cantuti-Castelvetri, I.; Rabin, B.; Joseph, J.

    Free radicals produced by exposure to heavy particles have been found to produce motor and behavioral toxicity effects in rats similar to those found during aging. The present research was designed to investigate the effects of exposure to 56Fe particles on the ability to detect novel arrangements in a given environment of male Sprague-Dawley rats. Using a test of spatial memory previously demonstrated to be sensitive to aging, open-field activity and reaction to spatial and non-spatial changes were measured in a group that received a dose of 1.5 Gy (n=10) of 56Fe heavy particle radiation or in non- radiated controls. Animals irradiated with 1.5 Gy of56Fe particles exhibited some age-like effects in animals tested, even though they were for the most part, subtle. Animals took longer to enter, visited less and spent significantly less time in the middle and the center portions of the open-field independently of total frequency and duration of activity of both groups. Likewise, irradiated subjects reacted significantly more to novel objects placed in the open-field than did controls. However, irradiated subjects did not vary from controls in their exploration patterns when objects in the open-field were spatially rearranged. Thus, irradiation with a dose of 1.5 Gy of 56Fe high-energy particle radiation elicited age-like effects in general open-field exploratory behavior, but did not elicit age- like effects during the spatial and non-spatial rearrangement tasks. Supported by N.A.S.A. Grant NAG9-1190.

  15. Irradiation test HT-31: high-temperature irradiation behavior of LASL-made extruded fuel rods and LASL-made coated particles

    International Nuclear Information System (INIS)

    Wagner, P.; Reiswig, R.D.; Hollabaugh, C.M.; White, R.W.; Davidson, K.V.; Schell, D.H.

    1977-04-01

    Three LASL-made extruded graphite and coated particle fuel rods have been irradiated in the Oak Ridge National Laboratory High Fluence Isotope Reactor test HT-31. Test conditions were about 9 x 10 21 nvt(E > .18 MeV) at 1250 0 C. The graphite matrix showed little or no effect of the irradiation. LASL-made ZrC containing coated particles with ZrC coats and ZrC-doped pyrolytic carbon coats showed no observable effects of the irradiation

  16. Specific features of reactor or cyclotron {alpha}-particles irradiated beryllium microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Khomutov, A M [A.A.Bochvar All-Russia Research Inst. of Inorganic Materials (VNIINM), Moscow (Russian Federation); Gromov, B F; Karabanov, V N [and others

    1998-01-01

    Studies were carried out into microstructure changes accompanying helium swelling of Be reactor neutron irradiated at 450degC or {alpha}-particles implanted in cyclotron to reach the same volume accumulation of He (6-8 ncm{sup 3} He/cm{sup 3} Be). The microstructures of reactor irradiated and implanted samples were compared after vacuum anneal at 600-800degC up to 50h. The irradiated samples revealed the etchability along the grain boundaries in zones formed by adequately large equilibrium helium pores. The width of the zones increased with the annealing time and after 50h reached 30{mu}. Depleted areas 2-3{mu} dia were observed in some regions of near grain boundary zones. The roles of grain boundaries and manufacturing pores as vacancies` sources and helium sinks are considered. (author)

  17. Changes in the surface electronic states of semiconductor fine particles induced by high energy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yamaki, Tetsuya; Asai, Keisuke; Ishigure, Kenkichi [Tokyo Univ. (Japan); Shibata, Hiromi

    1997-03-01

    The changes in the surface electronic states of Q-sized semiconductor particles in Langmuir-Blodgett (LB) films, induced by high energy ion irradiation, were examined by observation of ion induced emission and photoluminescence (PL). Various emission bands attributed to different defect sites in the band gap were observed at the initial irradiation stage. As the dose increased, the emissions via the trapping sites decreased in intensity while the band-edge emission developed. This suggests that the ion irradiation would remove almost all the trapping sites in the band gap. The low energy emissions, which show a multiexponential decay, were due to a donor-acceptor recombination between the deeply trapped carriers. It was found that the processes of formation, reaction, and stabilization of the trapping sites would predominantly occur under the photooxidizing conditions. (author)

  18. The effect of fast particles' irradiation on electrooptical properties of GaP LEDs

    International Nuclear Information System (INIS)

    Gontaruk, O.; Kovalenko, A.; Malyj, E.; Petrenko, I.; Pinkovska, M.; Polivtcev, L.; Tartachnyk, V.

    2013-01-01

    The electrooptical properties of industrial AL 102 GaP light-emitting diodes (LEDs) irradiated with fast particles have been studied. 2 MeV electrons and fast reactor neutrons were used and devices' microplsma emitting, current-voltage and capacitance-voltage characteristics were measured. It was shown that electron irradiation in the range (2-5)10 16 cm -2 leads to the drop of microplasma emitting intensity, decrease of capacity and reverse currents and increase of reverse bias. The annealing study of current-voltage characteristics after neutron irradiation of diodes confirms the assumption about prevailing radiation influence on diode base due to induce of deep levels. (authors)

  19. Wear behaviour of Armco iron after irradiation with neutrons and alpha particles

    International Nuclear Information System (INIS)

    Szatzschneider, K.

    1977-04-01

    The effects of neutron and alpha particle irradiation on the wear behaviour of Armco iron were studied. For the investigation, a pin-desk test facility was designed and built. From the experiments an influence upon wear of the type of irradiation, and the radiation dose was determined, which, however, cannot be explained - on the basis of existing wear theories - by the change in the macroscopic-mechanical properties of the material. It has again been shown that an indication of the hardness is not sufficient to describe wear. The influence of the history of the material (irradiation, annealing, deformation) is very strong and connot be predicted because of the multiplicity of interdependences. Wear in the low wear area was identified as being due to oxidation, in the high wear area as metallic. (orig./GSC) [de

  20. N-type doping of InGaN by high energy particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yu, K.M. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley CA, 94720 (United States)

    2009-06-15

    This article reviews our extensive studies of the effects of native defects introduced by high energy particles on the electrical and optical properties of InGaN alloys. We show that the electronic properties of irradiated InGaN can be well described by the amphoteric defect model. Because of the extremely low position of the conduction band edge of InN the formation energy of native donor defects is very low in In-rich InGaN alloys. High energy particle irradiation of InN and In-rich InGaN, will therefore produce donor defects and result in more n-type materials. As the irradiation dose increases, the electron concentration increases until the Fermi energy E{sub F} approaches the Fermi stabilization energy E{sub FS}. At this point both donor and acceptor-type defects are formed at similar rates, and compensate each other, leading to stabilization of E{sub F} and a saturation of the electron concentration. Hence a large increase and then saturation in the Burstein-Moss shift of the optical absorption edge is also observed. Furthermore we also found that mobilities in the irradiated films can be well described by scattering from triply charged defects, providing strong evidence that native defects in InN are triple donors. The excellent agreement between the experimental results and predictions based on the ADM suggests that particle irradiation can be an effective and simple method to control the doping (electron concentration) in In-rich In{sub x}Ga{sub 1-x}N via native point defects. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. N-type doping of InGaN by high energy particle irradiation

    International Nuclear Information System (INIS)

    Yu, K.M.

    2009-01-01

    This article reviews our extensive studies of the effects of native defects introduced by high energy particles on the electrical and optical properties of InGaN alloys. We show that the electronic properties of irradiated InGaN can be well described by the amphoteric defect model. Because of the extremely low position of the conduction band edge of InN the formation energy of native donor defects is very low in In-rich InGaN alloys. High energy particle irradiation of InN and In-rich InGaN, will therefore produce donor defects and result in more n-type materials. As the irradiation dose increases, the electron concentration increases until the Fermi energy E F approaches the Fermi stabilization energy E FS . At this point both donor and acceptor-type defects are formed at similar rates, and compensate each other, leading to stabilization of E F and a saturation of the electron concentration. Hence a large increase and then saturation in the Burstein-Moss shift of the optical absorption edge is also observed. Furthermore we also found that mobilities in the irradiated films can be well described by scattering from triply charged defects, providing strong evidence that native defects in InN are triple donors. The excellent agreement between the experimental results and predictions based on the ADM suggests that particle irradiation can be an effective and simple method to control the doping (electron concentration) in In-rich In x Ga 1-x N via native point defects. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Survival of human osteosarcoma cells and normal human fibroblasts following alpha particle irradiation

    International Nuclear Information System (INIS)

    Lloyd, E.L.; Gemmell, M.A.

    1981-01-01

    Cell survival of human osteosarcoma cells in culture following alpha particle irradiation is reported here for the first time. The osteosarcoma cell line (TE-85) is found to be less sensitive to inactivation by 5.6 MeV alpha particles (LET 86 keV/μm) than normal diploid human fibroblasts (NFS). Values for the mean lethal doses were estimated to be 103 rads for the TE-85 cells compared with 68 rads for the NFS cultures irradiated under identical conditions. It is postulated that the aneuploidy of the tumor cells with increased DNA chromosomal material may confer a selective advantage for the survival of tumor cells relative to normal cells with diploid chromosomes

  3. Water and sludge treatment device provided with a system for irradiating by accelerated charged particles

    International Nuclear Information System (INIS)

    Azam, Guy; Bensussan, Andre; Levaillant, Claude; Huber, Harry; Mevel, Emile; Tronc, Dominique.

    1977-01-01

    Treatment system for a fluid made up of water and sludge, provided with a system for irradiating the fluid by a beam of accelerated charged particles comprising means for obtaining a constant flow of the fluid to be treated, facilities for monitoring this flow, an irradiation channel located on the path of the beam, in which the fluid to be treated can flow, a portion of this channel having at least one window transparent to the beam of accelerated particles. A safety system associated with the system for monitoring the characteristics of the beam and with the system for monitoring the flow of the fluid to be treated, stops the flow of the fluid and the recycling of the fluid defectively treated [fr

  4. Performance Analysis Review of Thorium TRISO Coated Particles during Manufacture, Irradiation and Accident Condition Heating Tests

    International Nuclear Information System (INIS)

    2015-03-01

    Thorium, in combination with high enriched uranium, was used in all early high temperature reactors (HTRs). Initially, the fuel was contained in a kernel of coated particles. However, particle quality was low in the 1960s and early 1970s. Modern, high quality, tristructural isotropic (TRISO) fuel particles with thorium oxide and uranium dioxide (UO 2 ) had been manufactured since 1978 and were successfully demonstrated in irradiation and accident tests. In 1980, HTR fuels changed to low enriched uranium UO 2 TRISO fuels. The wide ranging development and demonstration programme was successful, and it established a worldwide standard that is still valid today. During the process, results of the thorium work with high quality TRISO fuel particles had not been fully evaluated or documented. This publication collects and presents the information and demonstrates the performance of thorium TRISO fuels.This publication is an outcome of the technical contract awarded under the IAEA Coordinated Research Project on Near Term and Promising Long Term Options for Deployment of Thorium Based Nuclear Energy, initiated in 2012. It is based on the compilation and analysis of available results on thorium TRISO coated particle performance in manufacturing and during irradiation and accident condition heating tests

  5. SERS study of transformation of phenylalanine to tyrosine under particle irradiation

    Science.gov (United States)

    Zhang, Jingjing; Huang, Qing; Yao, Guohua; Ke, Zhigang; Zhang, Hong; Lu, Yilin

    2014-08-01

    Surface enhanced Raman scattering or spectroscopy (SERS) is a very powerful analytical tool which has been widely applied in many scientific research and application fields. It is therefore also very intriguing for us to introduce SERS technique in the radiobiological research, where in many cases only a very few of biomolecules are subjected to changes which however can lead to significant biological effects. The radiation induced biochemical reactions are normally very sophisticated with different substances produced in the system, so currently it is still a big challenge for SERS to analyze such a mixture system which contains multiple analytes. In this context, this work aimed to establish and consolidate the feasibility of SERS as an effective tool in radiation chemistry, and this purpose, we employed SERS as a sensitive probe to a known process, namely, the oxidation of phenylalanine (Phe) under particle irradiation, where the energetic particles were obtained from either plasma discharge or electron-beam. During the irradiation, three types of tyrosine (Tyr), namely, p-Tyr, m-Tyr and o-Tyr were produced, and all these tyrosine isomers together with Phe could be identified and measured based on the SERS spectral analysis of the corresponding enhanced characteristic signals, namely, 1002 cm-1 for Phe, 1161 cm-1 for p-Tyr, 990 cm-1 for m-Tyr, and 970 cm-1 for o-Tyr, respectively. The estimation of the quantities of different tyrosine isomers were also given and verified by conventional method such as high performance liquid chromatography (HPLC). As for comparison of different ways of particle irradiation, our results also indicated that electron-beam irradiation was more efficient for converting Phe into Tyr than plasma discharge treatment, confirming the role of hydroxyl radicals in the Phe-Tyr conformation. Therefore, our work has not only demonstrated that SERS can be successfully applied in the radiobiological study, but also given insights into the

  6. Irradiation performance of coated fuel particles with fission product retaining kernel additives

    International Nuclear Information System (INIS)

    Foerthmann, R.

    1979-10-01

    The four irradiation experiments FRJ2-P17, FRJ2-P18, FRJ2-P19, and FRJ2-P20 for testing the efficiency of fission product-retaining kernel additives in coated fuel particles are described. The evaluation of the obtained experimental data led to the following results: - zirconia and alumina kernel additives are not suitable for an effective fission product retention in oxide fuel kernels, - alumina-silica kernel additives reduce the in-pile release of Sr 90 and Ba 140 from BISO-coated particles at temperatures of about 1200 0 C by two orders of magnitude, and the Cs release from kernels by one order of magnitude, - effective transport coefficients including all parameters which contribute to kernel release are given for (Th,U)O 2 mixed oxide kernels and low enriched UO 2 kernels containing 5 wt.% alumina-silica additives: 10g sub(K)/cm 2 s -1 = - 36 028/T + 6,261 (Sr 90), 10g Dsub(K)/cm 2 c -2 = - 29 646/T + 5,826 (Cs 134/137), alumina-silica kernel additives are ineffective for retaining Ag 110 m in coated particles. However, also an intact SiC-interlayer was found not to be effective at temperatures above 1200 0 C, - the penetration of the buffer layer by fission product containing eutectic additive melt during irradiation can be avoided by using additives which consist of alumina and mullite without an excess of silica, - annealing of LASER-failed irradiated particles and the irradiation test FRJ12-P20 indicate that the efficiency of alumina-silica kernel additives is not altered if the coating becomes defect. (orig.) [de

  7. Anisotropy variation of crystallographic orientation in pyrocarbon coatings of fuel particles by annealing and neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Koizlik, K.

    1973-04-15

    This document is a translation of those parts of the German report Jul-868-RW concerned with changes in anisotropy as determined using an optical technique on pyrocarbon coatings on fuel particles resulting from annealing and neutron irradiations. Two lists of contents are included, one is for the present document and the other is the full contents of the original report and is included for the generl interest of users.

  8. Post Irradiation TEM Investigation of ZrN Coated U(Mo) Particles Prepared with FIB

    Energy Technology Data Exchange (ETDEWEB)

    Van Renterghem, W.; Leenaers, A.; Van den Berghe, S.; Miller, B. D.; Gan, J.; Madden, J. W.; Keiser, D. D.; Palancher, H.; Hofman, G. L.; Breitkreuz, H.

    2015-10-01

    In the framework of the Selenium project, two dispersion fuel plates were fabricated with Si and ZrN coated fuel particles and irradiated in the Br2 reactor of SCK•CEN to high burn-up. The first analysis of the irradiated plate proved the reduced swelling of the fuel plate and interaction layer growth up to 70% burn-up. The question was raised how the structure of the interaction layer had been affected by the irradiation and how the structure of the fuel particles had evolved. Hereto, samples from the ZrN coated UMo particles were prepared for transmission electron microscopy (TEM) using focused ion beam milling (FIB) at INL. The FIB technique allowed to precisely select the area of the interaction layer and/or fuel to produce a sample that is TEM transparent over an area of 20 by 20 µm. In this contribution, the first TEM results will be presented from the 66% burn-up sample.

  9. Dense particles and slow sedimenting particles produced by ultraviolet irradiation of poliovirus

    International Nuclear Information System (INIS)

    Wetz, K.; Zeichhardt, H.; Willingmann, P.; Habermehl, K.-O.

    1983-01-01

    Low doses of u.v. radiation rapidly inactivate poliovirus, the virus progressively converting into dense particles (DPs) of buoyant density 1.44 g/ml in CsCl. The DPs are structurally and antigenically related to standard virus (N-antigen), i.e. indistinguishable from virus in their RNA and protein content and in sedimentation properties. Furthermore, there is no difference in reactivity of the structural proteins of virus and DPs with the monofunctional reagent [ 3 H]N-succinimidyl propionate ( 3 H-NSP). However, DPs differ from virus in that their capsids are permeable to several ions, and they can be degraded by RNase and protease. Increasing the radiation dose causes a successive transformation of DPs into 105S slow-sedimenting particles (SSPs), antigenically related to 76S artificial empty capsids (AECs) or H-antigen, but differing physically and structurally. The SSPs have a higher S value than AECs and contain all the capsid proteins, including VP4, and the RNA, both of these macromolecules being absent from AECs. It is concluded, therefore, that transformation from N- to H- antigenicity by u.v. radiation does not require release of RNA and VP4. Conversion of virus particles to SSPs correlates with altered reactivity of VP2 and to a lesser extent VP1 and VP3, with the monofunctional reagent 3 H-NSP. (author)

  10. Dense particles and slow sedimenting particles produced by ultraviolet irradiation of poliovirus

    Energy Technology Data Exchange (ETDEWEB)

    Wetz, K.; Zeichhardt, H.; Willingmann, P.; Habermehl, K.O. (Freie Univ. Berlin (Germany, F.R.))

    1983-06-01

    Low doses of u.v. radiation rapidly inactivate poliovirus, the virus progressively converting into dense particles (DPs) of buoyant density 1.44 g/ml in CsCl. The DPs are structurally and antigenically related to standard virus (N-antigen), i.e. indistinguishable from virus in their RNA and protein content and in sedimentation properties. Furthermore, there is no difference in reactivity of the structural proteins of virus and DPs with the monofunctional reagent (/sup 3/H)N-succinimidyl propionate (/sup 3/H-NSP). However, DPs differ from virus in that their capsids are permeable to several ions, and they can be degraded by RNase and protease. Increasing the radiation dose causes a successive transformation of DPs into 105S slow-sedimenting particles (SSPs), antigenically related to 76S artificial empty capsids (AECs) or H-antigen, but differing physically and structurally. The SSPs have a higher S value than AECs and contain all the capsid proteins, including VP4, and the RNA, both of these macromolecules being absent from AECs. It is concluded, therefore, that transformation from N- to H- antigenicity by u.v. radiation does not require release of RNA and VP4. Conversion of virus particles to SSPs correlates with altered reactivity of VP2 and to a lesser extent VP1 and VP3, with the monofunctional reagent /sup 3/H-NSP.

  11. Neutron irradiation of bacteria in the presence and absence of secondary charged-particle equilibrium

    International Nuclear Information System (INIS)

    Lunec, J.; Cramp, W.A.; Hornsey, S.

    1980-01-01

    The survival rate of Shigella flexneri has been measured for irradiation with 7-MeV neutrons in the presence and absence of secondary charged-particle equilibrium. The data were analyzed to assess the separate response of the cells to the knock-on proton and α-particle plus heavy-recoil components. A detailed consideration of the frequency of α-particle and heavy-recoil traversals of the cell has been made to explain our results, and in addition we have applied this approach to analyze the earlier results obtained with mammalian cells. We conclude that of the secondary charged-particles produced by the Hammersmith neutron beam, the highest LET particles, the heavy-recoil nuclei, contribute a minor proportion of damage to bacteria but form a major contribution of damage in mammalian cells. The reduction in oxygen enhancement ratio (OER) with neutrons compared with low LET radiation for mammalian cells is due almost entirely to the influence of the heavy recoils and the contribution of the α-particle and knock-on protons to the reduction of the OER is relatively minor. For Shigella flexneri the α particles and heavy recoils make approximately equal contributions to the reduction in OER

  12. Investigation on the biological effects of pharynx irradiation by single-particle microbeam and C.elegans immobilization

    International Nuclear Information System (INIS)

    Guo Xiaoying; Yang Gen; Chen Lianyun; Wu Lijun; Li Buqing

    2010-01-01

    Using C.elegans- with clear genetic background, easy genetic maneuverability, small individual, transparence, easily penetrated by a variety of particle as a in vivo model organism, irradiation damage at the individual level of the signal transduction and the mechanism research were investigated. In order to radiate accurately, the worms need Immobilize. The results showed that the ether: ethanol = 1:1 mixture, enabled the worms quickly anesthesia, and kept the worms Immobilization in the whole irradiation process, then quickly recovered after irradiation and recovery rate of 100%. On the basis, the laved and the apoptotic cells in the distal gonad would be test when the worm pharynx were irradiated by single-particle microbeam. The primary results showed that the apoptotic cells in distal gonad significantly increased when the worm pharynx were irradiated 5000 particles. (authors)

  13. Cooperation of endothelin-1 signaling with melanosomes plays a role in developing and/or maintaining human skin hyperpigmentation

    Directory of Open Access Journals (Sweden)

    Daiki Murase

    2015-10-01

    Full Text Available Skin hyperpigmentation is characterized by increased melanin synthesis and deposition that can cause significant psychosocial and psychological distress. Although several cytokine-receptor signaling cascades contribute to the formation of ultraviolet B-induced cutaneous hyperpigmentation, their possible involvement in other types of skin hyperpigmentation has never been clearly addressed. Since our continuous studies using skin specimens from more than 30 subjects with ethnic skin diversity emphasized a consistent augmentation in the expression of endothelin-1 (ET-1 and its receptor (Endothelin B receptor, ET-B in hyperpigmented lesions, including senile lentigos (SLs, the precise function of ET-1 signaling was investigated in the present study. In line with previous studies, ET-1 significantly induced melanogenesis followed by increases in melanosome transport in melanocytes and in its transfer to keratinocytes while inhibition of ET-B function substantially depressed melanogenic ability in tissue-cultured SLs. Additionally, in agreement with a previous report that the formation of autophagosomes rather than melanosomes is stimulated according to starvation or defective melanosome production, ET-1 was found to remarkably augment the expression of components necessary for early melanosome formation, indicating its counteraction against autophagy-targeting melanosome degradation in melanocytes. Despite the lack of substantial impact of ET-1 on keratinocyte melanogenic functions, the expression of ET-1 was enhanced following melanosome uptake by keratinocytes. Taken together, our data suggest that ET-1 plays a substantial role in the development and/or maintenance of skin hyperpigmentation in reciprocal cooperation with increased melanosome incorporation.

  14. Silencing of GPNMB by siRNA Inhibits the Formation of Melanosomes in Melanocytes in a MITF-Independent Fashion

    Science.gov (United States)

    Zhu, Cansheng; Yuan, Xiaoying; Li, Dongguang; Gu, Weijie; Ma, Huimin; Xie, Xin; Gao, Tianwen

    2012-01-01

    Background Melanosomes are specialized membrane-surrounded organelles, which are involved in the synthesis, storage and transport of melanin. Glycoprotein (transmembrane) non-metastatic melanoma protein b (GPNMB), a melanosome-specific structural protein, shares significant amino acid sequence homology with Pmel-17. Proteomic analysis demonstrated that GPNMB is present in all stages (I-IV) of melanosomes. However, little is known about the role of GPNMB in melanosomes. Methodology/Principal Findings Using real-time quantitative PCR, Western blotting and immunofluorescence analysis, we demonstrated that the expression of GPNMB in PIG1 melanocytes was up-regulated by ultraviolet B (UVB) radiation. Transmission electron microscopy analysis showed that the total number of melanosomes in PIG1 melanocytes was sharply reduced by GPNMB-siRNA transfection. Simultaneously, the expression levels of tyrosinase (Tyr), tyrosinase related protein 1 (Trp1), Pmel17/gp100 and ocular albinism type 1 protein (OA1) were all significantly attenuated. But the expression of microphthalmia-associated transcription factor (MITF) was up-regulated. Intriguingly, in GPNMB silenced PIG1 melanocytes, UVB radiation sharply reduced MITF expression. Conclusion Our present work revealed that the GPNMB was critical for the formation of melanosomes. And GPNMB expression down-regulation attenuated melanosome formation in a MITF-independent fashion. PMID:22912767

  15. Differential Effects of Alpha-Particle Radiation and X-Irradiation on Genes Associated with Apoptosis

    International Nuclear Information System (INIS)

    Chauhan, V.; Howland, M.; Chen, J.; Kutzner, B.; Wilkins, R.C.

    2011-01-01

    This study examined differential effects of alpha-(α) particle radiation and X-rays on apoptosis and associated changes in gene expression. Human monocytic cells were exposed to a-particle radiation and X-rays from 0 to 1.5 Gy. Four days postexposure, cell death was measured by flow cytometry and 84 genes related to apoptosis were analyzed using real-time PCR. On average, 33% of the cells were apoptotic at 1.5 Gy of a-particle radiation. Transcript profiling showed statistical expression of 15 genes at all three doses tested. Cells exposed to X-rays were <5% apoptotic at ∼1.5 Gy and induced less than a 2-fold expression in 6 apoptotic genes at the higher doses of radiation. Among these 6 genes, Fas and TNF-α were common to the α-irradiated cells. This data suggests that α-particle radiation initiates cell death by TNF-a and Fas activation and through intermediate signalling mediators that are distinct from X-irradiated cells

  16. Electron probe micro-analysis of irradiated Triso-coated UO2 particles, (1)

    International Nuclear Information System (INIS)

    Ogawa, Toru; Minato, Kazuo; Fukuda, Kosaku; Ikawa, Katsuichi

    1983-11-01

    The Triso-coated low-enriched UO 2 particles were subjected to the post-irradiation electron probe micro-analysis. Observations and analyses on the amoeba effect, inclusions and solutes in the UO 2 matrix were made. In the cooler side of the particle which suffered extensive kernel migration, two significant features were observed: (1) the wake of minute particles, presumably UO 2 , left by the moving kernel in the carbon phase and (2) carbon precipitation in the pores and along the grain boundaries of the UO 2 kernel. Both features could be hardly explained by the gas-phase mechanism of carbon transport and rather suggest the solid state mechanism. Two-types of 4d-transition metal inclusions were observed: the one which was predominantly Mo with a fraction of Tc and another which was enriched with Ru and containing significant amount of Si. The Mo and Si were also found in the UO 2 matrix; the observation led to the discussion of the oxygen potential in the irradiated Triso-coated UO 2 particle. (author)

  17. Melanosomal formation of PMEL core amyloid is driven by aromatic residues.

    Science.gov (United States)

    Hee, Jia Shee; Mitchell, Susan M; Liu, Xinran; Leonhardt, Ralf M

    2017-03-08

    PMEL is a pigment cell protein that forms physiological amyloid in melanosomes. Many amyloids and/or their oligomeric precursors are toxic, causing or contributing to severe, incurable diseases including Alzheimer's and prion diseases. Striking similarities in intracellular formation pathways between PMEL and various pathological amyloids including Aβ and PrP Sc suggest PMEL is an excellent model system to study endocytic amyloid. Learning how PMEL fibrils assemble without apparent toxicity may help developing novel therapies for amyloid diseases. Here we identify the critical PMEL domain that forms the melanosomal amyloid core (CAF). An unbiased alanine-scanning screen covering the entire region combined with quantitative electron microscopy analysis of the full set of mutants uncovers numerous essential residues. Many of these rely on aromaticity for function suggesting a role for π-stacking in melanosomal amyloid assembly. Various mutants are defective in amyloid nucleation. This extensive data set informs the first structural model of the CAF and provides insights into how the melanosomal amyloid core forms.

  18. The study of creep in stainless steel irradiated with fast neutron and alpha particles

    International Nuclear Information System (INIS)

    Correa, D.A.C.

    1985-01-01

    The objective of the present work is to study the creep behavior of the 316 type stainless steel 50% cold worked in different conditions of temperature and applied stress, after neutron radiation and Alfa particles implantation. For this experiment, non-irradiated samples, samples irradiated in the research reactor IEA-R1 with fast neutron (E≥ MeV) up to a fluence of 8.6.10 17 n/cm 2 , and samples implanted with Alfa particles in the cyclotron CV-28 with Helium concentrations of 5 and 26 appm, were creep tested with applied stresses of the 200-300 MPa at temperatures between 650 0 C and 700 0 C. The deformation versus time curves were plotted and it was observed tha the second stage is not well defined, with the creep rate increasing continuously until the occurrence of failure of the material. The study of the effect of increase from 200 MPa to 300 MPa at the same temperature was performed. It can be concluded that this increase produces an approximately 70% reductions in the fracture time of the material, with practically no influence in the total deformation. Samples were tested at different temperatures (650, 675 and 700 0 C) at a same applied stress (200 MPa). It has been observed that a temperature of 50 0 C produces 98,9% of reduction in the fracture time and almost doubles the total deformation. On neutron irradiated samples, creep tests were performed at the same temperature and stress of the non irradiated samples. Comparing the results obtained a tendency of embrittlement due to the neutron irradiation can be observed; no remarkable structure changes were detected due to small fast neutron. Microstructural and metalographic observations were performed before and after each creep test. (author) [pt

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

    Science.gov (United States)

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

    2018-04-01

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

  20. Bystander-induced apoptosis and premature differentiation in primary urothelial explants after charged particle microbeam irradiation

    International Nuclear Information System (INIS)

    Belyakov, O.V.; Folkard, M.; Mothersill, C.; Prise, K.M.; Michael, B.D.

    2002-01-01

    The ureter primary explant technique was developed to study bystander effects under in vivo like conditions where stem and differentiated cells are present. Irradiation was performed with a 3 He 2+ charged particle microbeam available at the Gray Cancer Institute, with high (∼2 μm) precision. Tissue sections from porcine ureters were pre-irradiated with the microbeam at a single location with 10 3 He 2+ particles (5 MeV; LET 70 keV.μm -1 ). After irradiation, the tissue section was incubated for 7 days, thus allowing the explant outgrowth to form. Total cellular damage (total fraction of micronucleated and apoptotic cells) was measured according to morphological criteria. Apoptosis was also assessed using a 3'-OH DNA end-labelling technique. Premature differentiation was estimated using antibodies to uroplakin III, a specific marker of terminal urothelial differentiation. Results of our experiments demonstrated a significant bystander-induced differentiation and a less significant increase in apoptotic and micronucleated cells. A hypothesis based on the protective nature of the bystander effect is proposed. (author)

  1. Thermoluminescence of NaF:Eu{sup 3+} phosphors exposed to beta particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Haro, A.R.; Cruz-Vazquez, C.; Orante-Barron, V.R. [Polymers and Materials Research Department, University of Sonora (Mexico); Bernal, R. [Physics Research Department, University of Sonora (Mexico); Kitis, G. [Nuclear Physics Laboratory, Aristotle University of Thessaloniki (Greece); Castano, V.M. [Applied Physics and Advanced Technology Center, Physics Institute, Autonomous National University of Mexico (Mexico)

    2013-02-15

    Pellet-shaped NaF:Eu{sup 3+} phosphors were synthesized by sintering. When a 5 K/s heating rate was used, the char-acteristic glow curves of beta particle irradiated samples exhibited two thermoluminescence (TL) maxima located at 401 K and 498 K, being the higher temperature max-imum the most intense. A peak located between 473 and 523 K is considered to have a position very suitable to assure good thermal stability of the stored TL, so this phosphor is attractive for radiation dosimetry. Beta particle irradiated samples displayed a TL response that increases as the radiation dose increased in the 0.08 to 42.5 Gy dose range, with a linear behavior below 10 Gy followed by a sublinear one for higher doses. Under storage after irradiation, the TL maximum at 498 K displayed a remarkable stability, and the TL fading revealed that the maximum at 401 K is not a single peak. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Alpha-particles microbeam irradiation: impact of reactive oxygen species in bystander effect

    International Nuclear Information System (INIS)

    Hanot, M.

    2008-11-01

    Ionizing radiation-induced bystander effects arise in bystander cells that receive signals from directly irradiated cells. To date, free radicals are believed to play an active role in the bystander response, but this is incompletely characterized. To mark temporal and spatial impacts of bystander effect, we employed a precise α-particle microbeam to target a small fraction of sub-confluent osteoblastic cell cultures (MC3T3-E1). We identified the cellular membrane and mitochondria like two distinct places generating reactive oxygen species. The global oxidative stress observed after irradiation was significantly attenuated after filipin treatment, evidencing the pivotal role of membrane in MC3T3-E1 cells bystander response. To determine impact of bystander effect at a cell level, cellular consequences of this membrane-dependant bystander effect were then investigated. A variable fraction of the cell population (10 to 100%) was individually targeted. In this case, mitotic death and micronuclei yield both increased in bystander cells as well as in targeted cells demonstrating a role of bystander signals between irradiated cells in an autocrine or paracrine manner. Our results indicate a complex interaction of direct irradiation and bystander signals that lead to a membrane-dependant amplification of cell responses. (author)

  3. Gas Generation from K East Basin Sludges and Irradiated Metallic Uranium Fuel Particles Series III Testing

    International Nuclear Information System (INIS)

    Schmidt, Andrew J.; Delegard, Calvin H.; Bryan, Samuel A.; Elmore, Monte R.; Sell, Rachel L.; Silvers, Kurt L.; Gano, Susan R.; Thornton, Brenda M.

    2003-01-01

    The path forward for managing of Hanford K Basin sludge calls for it to be packaged, shipped, and stored at T Plant until final processing at a future date. An important consideration for the design and cost of retrieval, transportation, and storage systems is the potential for heat and gas generation through oxidation reactions between uranium metal and water. This report, the third in a series (Series III), describes work performed at the Pacific Northwest National Laboratory (PNNL) to assess corrosion and gas generation from irradiated metallic uranium particles (fuel particles) with and without K Basin sludge addition. The testing described in this report consisted of 12 tests. In 10 of the tests, 4.3 to 26.4 g of fuel particles of selected size distribution were placed into 60- or 800-ml reaction vessels with 0 to 100 g settled sludge. In another test, a single 3.72-g fuel fragment (i.e., 7150-mm particle) was placed in a 60 ml reaction vessel with no added sludge. The twelfth test contained only sludge. The fuel particles were prepared by crushing archived coupons (samples) from an irradiated metallic uranium fuel element. After loading the sludge materials (whether fuel particles, mixtures of fuel particles and sludge, or sludge-only) into reaction vessels, the solids were covered with an excess of K Basin water, the vessels closed and connected to a gas measurement manifold, and the vessels back-flushed with inert neon cover gas. The vessels were then heated to a constant temperature. The gas pressures and temperatures were monitored continuously from the times the vessels were purged. Gas samples were collected at various times during the tests, and the samples analyzed by mass spectrometry. Data on the reaction rates of uranium metal fuel particles with water as a function of temperature and particle size were generated. The data were compared with published studies on metallic uranium corrosion kinetics. The effects of an intimate overlying sludge layer

  4. Fabrication of micropillar substrates using replicas of alpha-particle irradiated and chemically etched PADC films

    International Nuclear Information System (INIS)

    Ng, C.K.M.; Chong, E.Y.W.; Roy, V.A.L.; Cheung, K.M.C.; Yeung, K.W.K.; Yu, K.N.

    2012-01-01

    We proposed a simple method to fabricate micropillar substrates. Polyallyldiglycol carbonate (PADC) films were irradiated by alpha particles and then chemically etched to form a cast with micron-scale spherical pores. A polydimethylsiloxane (PDMS) replica of this PADC film gave a micropillar substrate with micron-scale spherical pillars. HeLa cells cultured on such a micropillar substrate had significantly larger percentage of cells entering S-phase, attached cell numbers and cell spreading areas. - Highlights: ► We proposed a simple method to fabricate micropillar substrates. ► Polyallyldiglycol carbonate films were irradiated and etched to form casts. ► Polydimethylsiloxane replica then formed the micropillar substrates. ► Attachment and proliferation of HeLa cells were enhanced on these substrates.

  5. Fabrication of micropillar substrates using replicas of alpha-particle irradiated and chemically etched PADC films

    Energy Technology Data Exchange (ETDEWEB)

    Ng, C.K.M. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Chong, E.Y.W. [Department of Orthopaedics and Traumatology, University of Hong Kong (Hong Kong); Roy, V.A.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Cheung, K.M.C.; Yeung, K.W.K. [Department of Orthopaedics and Traumatology, University of Hong Kong (Hong Kong); Yu, K.N., E-mail: appetery@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2012-07-15

    We proposed a simple method to fabricate micropillar substrates. Polyallyldiglycol carbonate (PADC) films were irradiated by alpha particles and then chemically etched to form a cast with micron-scale spherical pores. A polydimethylsiloxane (PDMS) replica of this PADC film gave a micropillar substrate with micron-scale spherical pillars. HeLa cells cultured on such a micropillar substrate had significantly larger percentage of cells entering S-phase, attached cell numbers and cell spreading areas. - Highlights: Black-Right-Pointing-Pointer We proposed a simple method to fabricate micropillar substrates. Black-Right-Pointing-Pointer Polyallyldiglycol carbonate films were irradiated and etched to form casts. Black-Right-Pointing-Pointer Polydimethylsiloxane replica then formed the micropillar substrates. Black-Right-Pointing-Pointer Attachment and proliferation of HeLa cells were enhanced on these substrates.

  6. Noise behaviour of semiinsulating GaAs particle detectors at various temperatures before and after irradiation

    International Nuclear Information System (INIS)

    Tenbusch, F.; Braunschweig, W.; Chu, Z.; Krais, R.; Kubicki, T.; Luebelsmeyer, K.; Pandoulas, D.; Rente, C.; Syben, O.; Toporowski, M.; Wittmer, B.; Xiao, W.J.

    1998-01-01

    We investigated the noise behaviour of surface barrier detectors (double sided Schottky contact) made of semiinsulating GaAs. Two types of measurements were performed: equivalent noise charge (ENC) and noise power density spectra in a frequency range from 10 Hz to 500 kHz. The shape of the density spectra are a powerful tool to examine the physical origin of the noise, before irradiation it is dominated by generation-recombination processes caused by deep levels. Temperature dependent noise measurements reveal the deep level parameters like activation energy and cross section, which are also extracted by analyzing the time transients of the charge pulse from α-particles. After irradiation with protons, neutrons and pions the influence of the deep levels being originally responsible for the noise is found to decrease and a reduction of the noise over the entire frequency range with increasing fluence is observed. (orig.)

  7. Modelling of a general purpose irradiation chamber using a Monte Carlo particle transport code

    International Nuclear Information System (INIS)

    Dhiyauddin Ahmad Fauzi; Sheik, F.O.A.; Nurul Fadzlin Hasbullah

    2013-01-01

    Full-text: The aim of this research is to stimulate the effectiveness use of a general purpose irradiation chamber to contain pure neutron particles obtained from a research reactor. The secondary neutron and gamma particles dose discharge from the chamber layers will be used as a platform to estimate the safe dimension of the chamber. The chamber, made up of layers of lead (Pb), shielding, polyethylene (PE), moderator and commercial grade aluminium (Al) cladding is proposed for the use of interacting samples with pure neutron particles in a nuclear reactor environment. The estimation was accomplished through simulation based on general Monte Carlo N-Particle transport code using Los Alamos MCNPX software. Simulations were performed on the model of the chamber subjected to high neutron flux radiation and its gamma radiation product. The model of neutron particle used is based on the neutron source found in PUSPATI TRIGA MARK II research reactor which holds a maximum flux value of 1 x 10 12 neutron/ cm 2 s. The expected outcomes of this research are zero gamma dose in the core of the chamber and neutron dose rate of less than 10 μSv/ day discharge from the chamber system. (author)

  8. Neutron activation analysis of several elements in the unicellular alga Cyanidium caldarium irradiated by α particles from neutron captured boron

    International Nuclear Information System (INIS)

    Yamaguchi, Shuho; Oota, Tadachika; Otani, Mayumi; Aso, Sueo

    1984-01-01

    The TRIGA MARK 2 atomic reactor was used not only for instrumental neutron activation analysis (INAA) but also as the irradiation source of α particles derived from the 10 B(n, α) 7 Li reaction for biological samples. The acidophilic and thermophilic unicellular alga (Cyanidium caldarium Geitler) was incubated for 20 hours after irradiation and then its elemental concentrations were analysed by INAA. An increase in the quantities of 56 Mn, 28 Al and 38 Cl, and a decrease of 27 Mg and 42 K were detected in the irradiated cells in contrast to non-irradiated cells. (author)

  9. Doping of semiconductors using radiation defects produced by irradiation with protons and alpha particles

    International Nuclear Information System (INIS)

    Kozlov, V.A.; Kozlovski, V.V.

    2001-01-01

    One of the modern methods for modifying semiconductors using beams of protons and alpha particles is analyzed; this modification is accomplished by the controlled introduction of radiation defects into the semiconductor. It is shown that doping semiconductors with radiation defects produced by irradiation with light ions opens up fresh opportunities for controlling the properties of semiconducting materials and for the development of new devices designed for optoelectronics, microelectronics, and nanoelectronics based on these materials; these devices differ favorably from those obtained by conventional doping methods, i.e., by diffusion, epitaxy, and ion implantation

  10. Two reactions method for accurate analysis by irradiation with charged particles

    International Nuclear Information System (INIS)

    Ishii, K.; Sastri, C.S.; Valladon, M.; Borderie, B.; Debrun, J.L.

    1978-01-01

    In the average stopping power method the formula error itself was negligible but systematic errors could be introduced by the stopping power data used in this formula. A method directly derived from the average stopping power method, but based on the use of two nuclear reactions, is described here. This method has a negligible formula error and does not require the use of any stopping power or range data: accurate and 'self-consistent' analysis by irradiation with charged particles is then possible. (Auth.)

  11. Momenta of particles emitted by target at intensive irradiation by low-energy ions

    CERN Document Server

    Beshenkov, V G; Marchenko, V A

    2002-01-01

    One measured the aggregate momenta of the target emitted particles at the intensive sputtering by E sub 0 approx = 0.5 keV energy heavy inert gases. For liquid and being under premelting temperature Ga target the measured values are close to the expected momenta of sputtered metallic atoms and reflection ions, for Cu and Zr targets they are essentially higher. One assumes that sputtering of atoms of gas-diffuser implanted into the target causes the surplus momentum. The estimated average energy of these atoms approx = 20 eV. Under Ga irradiation the implanted atoms diffuse mainly towards the surface and are desorbed

  12. Critical residues in the PMEL/Pmel17 N-terminus direct the hierarchical assembly of melanosomal fibrils

    Science.gov (United States)

    Leonhardt, Ralf M.; Vigneron, Nathalie; Hee, Jia Shee; Graham, Morven; Cresswell, Peter

    2013-01-01

    PMEL (also called Pmel17 or gp100) is a melanocyte/melanoma-specific glycoprotein that plays a critical role in melanosome development by forming a fibrillar amyloid matrix in the organelle for melanin deposition. Although ultimately not a component of mature fibrils, the PMEL N-terminal region (NTR) is essential for their formation. By mutational analysis we establish a high-resolution map of this domain in which sequence elements and functionally critical residues are assigned. We show that the NTR functions in cis to drive the aggregation of the downstream polycystic kidney disease (PKD) domain into a melanosomal core matrix. This is essential to promote in trans the stabilization and terminal proteolytic maturation of the repeat (RPT) domain–containing MαC units, precursors of the second fibrillogenic fragment. We conclude that during melanosome biogenesis the NTR controls the hierarchical assembly of melanosomal fibrils. PMID:23389629

  13. Performance of HTGR fertile particles irradiated in HFIR capsule HT-32

    International Nuclear Information System (INIS)

    Long, E.L. Jr.; Robbins, J.M.; Tiegs, T.N.; Kania, M.J.

    1980-04-01

    The HT-32 experiment was an uninstrumented capsule irradiated for four cycles in the target position of the High-Flux Isotope Reactor (HFIR). The experiment was designed to: provide supplemental simulated fuel rods for thermal transport and expansion measurements; test fertile kernels with Al 2 O 3 and SiO 2 additives for improved fission product retention; study the stability and permeability of low-temperature isotropic (LTI) pyrocarbon coatings; test Biso- and Triso-coatings derived in a large (0.24-m-dia) coating furnace with a frit distributor; investigate the performance of particles with an outer layer of SiC both as loose particles and as resin-bonded fuel rods; and evaluate high-density alumina as a potential high-temperature thermometry sheathing material

  14. Rotation of a Spherical Particle with Electrical Dipole Moment Induced by Steady Irradiation in a Static Electric Field

    Science.gov (United States)

    Grachev, A. I.

    2018-04-01

    Rotation of a spherical particle in a static electric field and under steady irradiation that induces an electric dipole moment in the particle is studied for the first time. Along with the general treatment of the phenomenon, we analyze possible mechanisms underlying the photoinduction of dipole moment in the particle. Estimations of the angular velocity and the power expended by the rotating particle are provided. The indicated characteristics reach their maximum values if the size of particles is within the range of 10 nm to 10 μm.

  15. Heavy particle irradiation, neurochemistry and behavior: thresholds, dose-response curves and recovery of function

    Science.gov (United States)

    Rabin, B. M.; Joseph, J. A.; Shukitt-Hale, B.

    2004-01-01

    Exposure to heavy particles can affect the functioning of the central nervous system (CNS), particularly the dopaminergic system. In turn, the radiation-induced disruption of dopaminergic function affects a variety of behaviors that are dependent upon the integrity of this system, including motor behavior (upper body strength), amphetamine (dopamine)-mediated taste aversion learning, and operant conditioning (fixed-ratio bar pressing). Although the relationships between heavy particle irradiation and the effects of exposure depend, to some extent, upon the specific behavioral or neurochemical endpoint under consideration, a review of the available research leads to the hypothesis that the endpoints mediated by the CNS have certain characteristics in common. These include: (1) a threshold, below which there is no apparent effect; (2) the lack of a dose-response relationship, or an extremely steep dose-response curve, depending on the particular endpoint; and (3) the absence of recovery of function, such that the heavy particle-induced behavioral and neural changes are present when tested up to one year following exposure. The current report reviews the data relevant to the degree to which these characteristics are common to neurochemical and behavioral endpoints that are mediated by the effects of exposure to heavy particles on CNS activity.

  16. The alpha-particle irradiator set up at the ISS for radiobiological studies on targeted and non-targeted effects

    International Nuclear Information System (INIS)

    Esposito, G.; Antonelli, F.; Belli, M.; Campa, A.; Simone, G.; Sorrentino, E.; Tabocchini, M.A.

    2008-01-01

    In this paper we describe the alpha-particle irradiator that has been set up at the Istituto Superiore di Sanita (ISS) for controlled exposure of cultured mammalian cells. It can be equipped with two different sources, namely 2'4'4'Cm and 2'4'1'Am, allowing irradiation at different dose-rates (typically 1-100 mGy/min). The irradiator has dimensions small enough to be inserted into a standard cell culture incubator to perform irradiation of cultured cells in physiological conditions. The dose uniformity is such that the variations in the irradiation area are less than ± 12% of the average dose value on different irradiation areas up to ∼ 25 cm'2. Moreover, in the framework of the FP6 Euratom Integrated Project Non-targeted effects of ionizing radiation (NOTE), Petri dishes were realized for housing permeable membrane insert(s) to be used in co-culture experiments. Aluminium shields were also realized for half shield irradiation experiments. The alpha-particle irradiator of the ISS has been successfully used for studying DNA damage, namely double strand breaks (DSB, as measured by the γ-H2AX assay), in directly hit and in bystander primary human fibroblasts [it

  17. Deoxyarbutin Possesses a Potent Skin-Lightening Capacity with No Discernible Cytotoxicity against Melanosomes

    OpenAIRE

    Miao, Fang; Shi, Ying; Fan, Zhi-Feng; Jiang, Shan; Xu, Shi-Zheng; Lei, Tie-Chi

    2016-01-01

    Safe and effective ingredients capable of removing undesired hyperpigmentation from facial skin are urgently needed for both pharmaceutical and cosmetic purposes. Deoxyarbutin (4-[(tetrahydro-2H-pyran-2-yl) oxy] phenol, D-Arb) is a glucoside derivative of hydroquinone. Here, we investigated the toxicity and efficacy of D-Arb at the sub-cellular level (directly on melanosomes) and skin pigmentation using in vivo and in vitro models to compare with its parent compound hydroquinone (1,4-benzened...

  18. Preparation and pigmented polyester coating of saw dust particle board using ultraviolet irradiation

    International Nuclear Information System (INIS)

    Darsono; Sugiarto Danu; Anik Sunarni

    2010-01-01

    Experiments on the preparation and pigmented polyester coating of saw dust particle board have been conducted using ultra-violet (UV) radiation curing. The adhesive used for preparation of particle board was the mixture of eugenol and isoeugenol residue as by product of clover oil distillation. Dry saw dust (20 – 40 mesh) was mixed with adhesive at concentration of 16 % b.w. The mixture then was hot pressed at 160, 170, and 180 kg/cm 2 , temperature of 160 °C for 30 minutes. Particle boards obtained have the density of 0.85 - 92 g/cm 3 , water content of 5.4 – 6.8 % and thickness swelling 45 – 62 % ( 2 hr immersion) and unmeasurable for 24 hr immersion due to brittle condition. It was found that particle boards have properties of modulus of rupture = 64 – 71 kgf/cm 2 , modulus of elasticity = 402 – 447 kgf/ cm 2 , and internal bond of 0.52 – 0.57 kgf/cm 2 . Cured coating made of the mixture of polyester resin, photoinitiator (2 and 3 % b.w) and pigment (1 and 2 % b.w) on particle board and irradiated at 1 – 4 m/min have pendulum hardness = 25.0 – 63.9 sec, pencil hardness = HB – 2H, % remaining = 92 – 100 %, glossy = 42.3 – 58.8 %, and color value of L = 54.3 – 73.9, a = -1.3 – 1.9, and b = 0.4 – 3.3. The cured coatings resist to chemical, solvent and stain, except against 10 % NaOH solution and red permanent marker stain. (author)

  19. Comparison of recovery in the rat lens epithelium after x-ray, fission neutron, or /sup 56/Fe particle irradiation

    International Nuclear Information System (INIS)

    Riley, E.F.; Lindgren, A.L.; Ainsworth, E.J.

    1985-01-01

    The authors are comparing the radiobiological effectiveness of 10 Gy (1000 rads) of 250 kVp X-rays, 2 Gy (200 rads) of fission neutrons, and 1.5 Gy (150 rds) of 600 MeV /sup 56/Fe particles (LET about 180-200 keV/μm). They are evaluating the persistence of latent radiation damage and the very slow recovery (> 1 month) in cells of the central zone of the rat lens epithelium. The central zone is essentially a G/sub o/ population of cells (1 mitotic figure per 2000 cells). These cells normally respond to the mitogenic stimulus of wounding with a ''burst'' of DNA synthesis at 14 hours and a ''burst'' of mitosis at 24 hours after wounding. Irradiation before wounding causes a delay and suppression of the response. With increasing time between irradiation and wounding, the authors note less delay and less suppression of the response. They also note fewer abnormal mitotic figures. For example, at 28 days the X-irradiated, neutron irradiated, and iron irradiated cells developed respectively, 39%, 36%, and 21% fewer abnormal mitotic figures than at 7 days post-irradiation. Slower recovery after /sup 56/Fe particle irradiation is indicated. They are now comparing the amounts of delay and suppression of the responses after exposure to the different radiations

  20. Performance assessment of the (Th,U)O2 HTI-Biso coated particle under PNP/HHT irradiation conditions

    International Nuclear Information System (INIS)

    Kania, M.J.; Nickel, H.

    1980-11-01

    The HTI Biso Particle, Variant-I: consisting of a dense 400 μm-diameter (Th,U)O 2 -kernel with a Biso coating using a methane derived pyrocarbon layer (HTI), is a candidate fuel for the advanced PNP/HHT High Temperature Reactor systems. This report presents the results of a comprehensive performance assessment of Variant-I represented by six relevant particle batches irradiated in 12 accelerated irradiation experiments. Fuel performance was judged based upon PNP/HHT qualification requirements with regard to in-reactor operating conditions and end-of-life (EOL) coated particle failure fraction. Fuel operating conditions in each irradiation experiment were obtained from two sources: 1) a thorough review of all available irradiation data on each experiment; and 2) a two-dimensional (R,theta) thermal modeling computer code, R2KTMP, was developed to calculate fuel operating temperature distributions within spherical elements. End-of-life particle failure fractions were determined from: gaseous fission product release, based on in-reactor R/B measurements and postirradiation annealing and room temperature investigations; solid fission product release, from single particle 137 Cs release into fuel element matrix and hot-gaseous chlorine leaching; and visual and ceramographic examinations. Failure fractions determined by solid fission product release yielded values 2-35 times higher than those determined by gaseous fission product release. (orig.) [de

  1. Studies of treatment for carcinoma by particle irradiation combined with surgery

    International Nuclear Information System (INIS)

    Tsunemoto, Hiroshi

    1981-01-01

    Studies of particle radiation therapy for cancer showed that osteosarcoma, Pancoast carcinoma of the lung, fixed metastatic cervical tumors responded well to fast neutron therapy. Head and neck cancer, esophagus cancer, cancer of the urinary tracts, malignant glioma, malignant melanoma, and soft tissue sarcoma responded to fast neutron therapy as well as conventional radiation therapy. Cancer of the tissues with low sensitivity for low LET beams responded very well to fast neutron therapy. The tolerant dose of fast neutron of the normal tissues, especially the skin, was estimated in order to perform salvage operation safely. No complication due to preoperative fast neutron irradiation was found in the cases of esophagus cancer, which may cause increase in survival rate. Proton beam therapy was promising as a procedure to be substituted partially for surgical operation and as a therapy combined with fast neutron therapy. (Ueda, J.)

  2. Neuroimmune response and sleep studies after whole body irradiation with high-LET particles

    Science.gov (United States)

    Marquette, C.; Mathieu, J.; Bertho, J.-M.; Galonnier, M.; Wysoki, J.; Maubert, C.; Balanzat, E.; Gerbin, R.; Aigueperse, J.; Clarençon, D.

    2009-10-01

    In order to investigate the biological effects of galactic rays on astronaut cerebral functions after space flight, mice were exposed to different heavy ions (HZE) in whole-body conditions at doses comparable to the galactic flux: 12C, 16O and 20Ne (95 MeV/u, at 42-76 mGy). Animals were also exposed to 42 mGy of 60Co radiation for comparison with HZE. The neuroimmune response, evaluated by interleukin-1 (IL-1) measurement, showed that this cytokine was produced 3 h after irradiation by 16O or 60Co. In contrast, neither 12C (56.7 mGy) nor 20Ne (76 mGy) induced IL-1 production. However, immunohistochemical staining of 12C-irradiated mouse brain tissue showed 2 months later a marked inflammatory reaction in the hippocampus and a diffuse response in parenchyma. Sleep studies were realized before and after exposure to 42 mGy of 16O and 76 mGy of 20Ne: only the 20Ne radiation displayed a small effect. A slight decrease in paradoxical sleep, corresponding to a reduction in the number of episodes of paradoxical sleep, was manifested between 8 and 22 days after exposure. Exposure to 12C and 16O induced no changes either in cellularity of spleen or thymus, or in caspase 3 activity (as much as four months after irradiation). Taken together, these data indicate that the CNS could be sensitive to heavy ions and that responses to HZE impact depend on the nature of the particle, the dose threshold and the time delay to develop biological processes. Differences in responses to different HZE highlight the complex biological phenomena to which astronauts are submitted during space flight.

  3. Neuro-immune response and sleep studies after whole body irradiation with high-LET particles

    International Nuclear Information System (INIS)

    Marquette, C.; Bertho, J.M.; Wysoki, J.; Maubert, C.; Gerbin, R.; Aigueperse, J.; Mathieu, J.; Galonnier, M.; Clarencon, D.; Balanzat, E.

    2009-01-01

    In order to investigate the biological effects of galactic rays on astronaut cerebral functions after space flight, mice were exposed to different heavy ions (HZE) in whole-body conditions at doses comparable to the galactic flux: 12 C, 16 O and 20 Ne (95 MeV/u, at 42-76 mGy). Animals were also exposed to 42 mGy of 60 Co radiation for comparison with HZE. The neuro-immune response, evaluated by interleukin-I (IL-1) measurement, showed that this cytokine was produced 3 h after irradiation by 16 O or 60 Co. In contrast, neither 12 C (56.7 mGy) nor 20 Ne (76 mGy) induced IL-1 production. However, immunohistochemical staining of 12 C-irradiated mouse brain tissue showed 2 months later a marked inflammatory reaction in the hippocampus and a diffuse response in parenchyma. Sleep studies were realized before and after exposure to 42 mGy of 16 O and 76 mGy of 20 Ne: only the 20 Ne radiation displayed a small effect. A slight decrease in paradoxical sleep, corresponding to a reduction in the number of episodes of paradoxical sleep, was manifested between 8 and 22 days after exposure. Exposure to 12 C and 16 O induced no changes either in cellularity of spleen or thymus, or in caspase 3 activity (as much as four months after irradiation). Taken together, these data indicate that the CNS could be sensitive to heavy ions and that responses to HZE impact depend on the nature of the particle, the dose threshold and the time delay to develop biological processes. Differences in responses to different HZE highlight the complex biological phenomena to which astronauts are submitted during space flight. (authors)

  4. Thermoluminescence of europium-doped zinc oxide exposed to beta particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Iriqui R, J. L.; Cruz V, C. [Universidad de Sonora, Departamento de Investigacion en Polimeros y Materiales, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Bernal, R. [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83000 Hermosillo, Sonora (Mexico); Castano, V. M., E-mail: jorgeiriqui@gimmunison.com [UNAM, Instituto de Fisica, Centro de Fisica Aplicada y Tecnologia Avanzada, Apdo. Postal 1-1010, 76000 Queretaro, Qro. (Mexico)

    2015-10-15

    Full text: Zn O is a promising material for a range of optoelectronics applications, due to its direct wide band gap (E{sub g} ∼3.3 eV at 300 K) and large exciton binding energy (60 MeV). Its applications include UV light emitters, varistors, surface acoustic wave devices, piezoelectric transducers, and chemical and gas sensing. Rare-earth activation of phosphors has long been seen as an effective process since coupling energy into the rare-earth-ion site, either by ionization, charge exchange or a resonance energy process, results in light production. It is reported that Europium modifies the response thermoluminescence (Tl) for pure zinc oxide, when is irradiated with X-ray, created a peak at 365 degrees C. In this work, Zn O:Eu phosphors were synthesized by a chemical method. Some samples were exposed to beta particle irradiation for doses ranging from 1 up to 100 Gy. Tl response as a function of dose is linear throughout the studied dose range. The glow curve exhibits three maxima, centered at 176, 279 and 340 degrees C. The reusability studies obtained after ten repeated cycles of annealing irradiation readout for the Zn O:Eu shows that the variation in the Tl response is ten percent and tends to stabilization. The results indicate that these new Zn O:Eu phosphors are promising detectors and dosimeters for beta radiation. The structural and morphological characterization was carried out by X-ray diffraction and scanning electron microscopy, respectively. (Author)

  5. Preventive effects of running exercise on bones in heavy ion particle irradiated rats

    International Nuclear Information System (INIS)

    Fukuda, Satoshi; Iida, Haruzo; Yan, Xueming

    2002-01-01

    We examined the effects of running exercise on preventing decreases in bone mineral and tissue volume after heavy ion particle irradiation in rats. Male Wistar rats experienced whole-body irradiation by heavy ion particle beam (C-290 MeV) at doses of 0.5, 1.0, and 5.0 Gy and were divided into voluntary running groups and control groups. Rats in the running groups ran on the treadmill 15 m/mim, 90 min/day for 35 days after exposure. At the end of the experiment, a tibia was obtained from each rat for measurement of bone mineral density (BMD) and cross-sectional area, strength strain index, and bone histomorphometric analysis. The weights of muscles and concentration of serum calcium were measured. Total BMD and trabecular BMD in the metaphysis and cortical BMD of the diaphysis of tibia in the running groups increased. Bone volume and trabecular thickness increased while trabecular separation decreased in the running groups compared to those in the control groups at respective doses. However, the osteoid surface and eroded surface varied in the running groups compared to those of the respective corresponding groups. The dynamic parameters such as mineralizing surface, mineral apposition rate, and bone formation rate in the running groups were varied, probably due to the differences in radiation-induced sensitivities of bones following radiation exposure. The overall results suggest that running exercise might have a beneficial effect on preventing bone mineral loss and changes in bone structure induced by space radiation, but it is necessary to examine the optimal conditions of running exercise response to doses. (author)

  6. Mitigation of radiation nephropathy after internal α-particle irradiation of kidneys

    International Nuclear Information System (INIS)

    Jaggi, Jaspreet Singh; Seshan, Surya V.; McDevitt, Michael R.; Sgouros, George; Hyjek, Elizabeth; Scheinberg, David A.

    2006-01-01

    Purpose: Internal irradiation of kidneys as a consequence of radioimmunotherapy, radiation accidents, or nuclear terrorism can result in radiation nephropathy. We attempted to modify pharmacologically, the functional and morphologic changes in mouse kidneys after injection with the actinium ( 225 Ac) nanogenerator, an in vivo generator of α- and β-particle emitting elements. Methods and Materials: The animals were injected with 0.35 μCi of the 225 Ac nanogenerator, which delivers a dose of 27.6 Gy to the kidneys. Then, they were randomized to receive captopril (angiotensin-converting enzyme inhibitor), L-158,809 (angiotensin II receptor-1 blocker), spironolactone (aldosterone receptor antagonist), or a placebo. Results: Forty weeks after the 225 Ac injection, the placebo-control mice showed a significant increase in blood urea nitrogen (BUN) (87.6 ± 6.9 mg/dL), dilated Bowman spaces, and tubulolysis with basement membrane thickening. Captopril treatment accentuated the functional (BUN 119.0 ± 4.0 mg/dL; p <0.01 vs. placebo controls) and histopathologic damage. In contrast, L-158,809 offered moderate protection (BUN 66.6 ± 3.9 mg/dL; p = 0.02 vs. placebo controls). Spironolactone treatment, however, significantly prevented the development of histopathologic and functional changes (BUN 31.2 ± 2.5 mg/dL; p <0.001 vs. placebo controls). Conclusions: Low-dose spironolactone and, to a lesser extent, angiotensin receptor-1 blockade can offer renal protection in a mouse model of internal α-particle irradiation

  7. Radiation Quality Effects on Transcriptome Profiles in 3-d Cultures After Particle Irradiation

    Science.gov (United States)

    Patel, Z. S.; Kidane, Y. H.; Huff, J. L.

    2014-01-01

    In this work, we evaluate the differential effects of low- and high-LET radiation on 3-D organotypic cultures in order to investigate radiation quality impacts on gene expression and cellular responses. Reducing uncertainties in current risk models requires new knowledge on the fundamental differences in biological responses (the so-called radiation quality effects) triggered by heavy ion particle radiation versus low-LET radiation associated with Earth-based exposures. We are utilizing novel 3-D organotypic human tissue models that provide a format for study of human cells within a realistic tissue framework, thereby bridging the gap between 2-D monolayer culture and animal models for risk extrapolation to humans. To identify biological pathway signatures unique to heavy ion particle exposure, functional gene set enrichment analysis (GSEA) was used with whole transcriptome profiling. GSEA has been used extensively as a method to garner biological information in a variety of model systems but has not been commonly used to analyze radiation effects. It is a powerful approach for assessing the functional significance of radiation quality-dependent changes from datasets where the changes are subtle but broad, and where single gene based analysis using rankings of fold-change may not reveal important biological information. We identified 45 statistically significant gene sets at 0.05 q-value cutoff, including 14 gene sets common to gamma and titanium irradiation, 19 gene sets specific to gamma irradiation, and 12 titanium-specific gene sets. Common gene sets largely align with DNA damage, cell cycle, early immune response, and inflammatory cytokine pathway activation. The top gene set enriched for the gamma- and titanium-irradiated samples involved KRAS pathway activation and genes activated in TNF-treated cells, respectively. Another difference noted for the high-LET samples was an apparent enrichment in gene sets involved in cycle cycle/mitotic control. It is

  8. Distance distribution of bystander effects in alpha-particle irradiated cell populations using a CR-39-based culture dish

    International Nuclear Information System (INIS)

    Gaillard, S.; Pusset, D.; Toledo, S.M. de; Azzam, E.I.; Fromm, M.

    2008-01-01

    Propagation of induced biological effects from irradiated to non-irradiated cells is known to occur in cell cultures exposed to low fluences of charged particles. These bystander effects are currently investigated using microbeam or non-microbeam (broad beams) irradiation techniques. Identification of the targeted and non-targeted bystander cells is critical to our understanding of mechanisms underlying such effects. We developed a novel cell culture dish where the base consists of a thin CR-39 sheet grafted on a thin polyethylene terephthalate (PET) foil. The validity of this device in identifying not only irradiated cells, but also the cellular compartment traversed by the particle track is described. We have optimized track etch parameters that do not interfere with measurement of induced biological endpoints under normal incident irradiation. Thus the culture dishes can be used to determine distance distributions for the propagation of induced biological effects from a hit cell to bystander cells. We describe the computer code developed to determine the distance distributions of propagated biological stress responses in normal human fibroblast cells exposed to very low fluences of alpha particles

  9. Thermoluminescent dependence with the particle size of polyminerals in food irradiated of Mexican spices

    International Nuclear Information System (INIS)

    Teuffer Z, C.; Cruz Z, E.; Calderon, T.; Chernov, V.; Barboza F, M.

    2004-01-01

    The influence of grain size on Tl was analysed in poly minerals extracted from Mexican spices as Origanum vulgare L. (oregano) y Capsicum annun (chile guajillo). The poly minerals size were selected by Zimmerman method up to 10 μm and exposed to 0.5-10 kGy range from 60 Co. The glow curves were centered at 166 C for Capsicum annun and at 126 C for Origanum vulgare l. In both cases was observed at 5 kGy a weak saturation for Tl response. This behaviour is attributed to feldspar and quartz are present in the samples and this results is in agreement with other european spices obtained. For >10 μm particle size the Tl response increased respect to the doses, and it is possible that increase the organic impurities quantities are present in the samples and contributed to the Tl when the samples were thermally excited. The aim of this work is provide more ideas with regard to the behaviour of luminescence emission as dependent of the size particle in the irradiated spices. The methodology might useful for quality control also in radiation processing. (Author)

  10. Activation cross sections of longer-lived radionuclides produced in germanium by alpha particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Takács, S., E-mail: stakacs@atomki.hu [Institute for Nuclear Research, Hungarian Academy of Sciences, Atomki, 4026 Debrecen (Hungary); Takács, M.P.; Ditrói, F. [Institute for Nuclear Research, Hungarian Academy of Sciences, Atomki, 4026 Debrecen (Hungary); Aikawa, M. [Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan); Haba, H.; Komori, Y. [Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan)

    2016-09-15

    The cross sections of alpha particles induced nuclear reactions on natural germanium were investigated by using the standard stacked foil target technique, the activation method and high resolution gamma spectrometry. Targets with thickness of about 1 μm were prepared from natural Ge by vacuum evaporation onto 25 μm thick polyimide (Kapton) backing foils. Stacks were composed of Kapton-Ge-Ge-Kapton sandwich target foils and additional titanium monitor foils with nominal thickness of 11 μm to monitor the beam parameters using the {sup nat}Ti(α,x){sup 51}Cr reaction. The irradiations were done with E{sub α} = 20.7 and E{sub α} = 51.25 MeV, I{sub α} = 50 nA alpha particle beams for about 1 h. Direct or cumulative activation cross sections were determined for production of the {sup 72,73,75}Se, {sup 71,72,74,76,78}As, and {sup 69}Ge radionuclides. The obtained experimental cross sections were compared to the results of theoretical calculations taken from the TENDL data library based on the TALYS computer code. A comparison was made with available experimental data measured earlier. Thick target yields were deduced from the experimental cross sections and compared with the data published before.

  11. Radiation response of ODS ferritic steels with different oxide particles under ion-irradiation at 550 °C

    Science.gov (United States)

    Song, Peng; Morrall, Daniel; Zhang, Zhexian; Yabuuchi, Kiyohiro; Kimura, Akihiko

    2018-04-01

    In order to investigate the effects of oxide particles on radiation response such as hardness change and microstructural evolution, three types of oxide dispersion strengthened (ODS) ferritic steels (named Y-Ti-ODS, Y-Al-ODS and Y-Al-Zr-ODS), mostly strengthened by Y-Ti-O, Y-Al-O and Y-Zr-O dispersoids, respectively, were simultaneously irradiated with iron and helium ions at 550 °C up to a damage of 30 dpa and a corresponding helium (He) concentration of ∼3500 appm to a depth of 1000-1300 nm. A single iron ion beam irradiation was also performed for reference. Transmission electron microscopy revealed that after the dual ion irradiation helium bubbles of 2.8, 6.6 and 4.5 nm in mean diameter with the corresponding number densities of 1.1 × 1023, 2.7 × 1022 and 3.6 × 1022 m-3 were observed in Y-Ti-ODS, Y-Al-ODS and Y-Al-Zr-ODS, respectively, while no such bubbles were observed after single ion irradiation. About 80% of intragranular He bubbles were adjacent to oxide particles in the ODS ferritic steels. Although the high number density He bubbles were observed in the ODS steels, the void swelling in Y-Ti-ODS, Y-Al-ODS and Y-Al-Zr-ODS was still small and estimated to be 0.13%, 0.53% and 0.20%, respectively. The excellent swelling resistance is dominantly attributed to the high sink strength of oxide particles that depends on the morphology of particle dispersion rather than the crystal structure of the particles. In contrast, no dislocation loops were produced in any of the irradiated steels. Nanoindentation measurements showed that no irradiation hardening but softening was found in the ODS ferritic steels, which was probably due to irradiation induced dislocation recovery. The helium bubbles in high number density never contributed to the irradiation hardening of the ODS steels at these irradiation conditions.

  12. Fluorescent nuclear track images of Ag-activated phosphate glass irradiated with photons and heavy charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Kurobori, Toshio, E-mail: kurobori@staff.kanazawa-u.ac.jp [Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192 (Japan); Yanagida, Yuka [Oarai Research Center, Chiyoda Technol Corporation, Oarai-machi, Ibaraki 311-1313 (Japan); Kodaira, Satoshi [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Shirao, Taichi [Nikon Instech Co., Ltd., Tanakanishi, Sakyo-ku, Kyoto 606-8221 (Japan)

    2017-05-21

    In this paper we report about the demonstration of the nuclear track imaging capabilities of Ag-activated phosphate glass. A 375 nm laser and confocal laser scanning microscopy (CLSM) were respectively used for track excitation and detection. Specifically, the blue and orange radiophotoluminescent (RPL) tracks and dose distributions observed after irradiation with soft X-rays, gamma rays and heavy charged particles (HCPs) are examined. In addition, the origins of the reductions in RPL efficiency for high-dose X-ray irradiation and for irradiation with HCPs with high linear energy transfer (LET) values are investigated via a CLSM and a conventional fluorescent reader and discussed. - Highlights: • 3D track images are demonstrated using a confocal laser microscopy. • Fluorescent track detectors are based on RPL Ag-doped phosphate glass. • The dose distributions are examined for X-ray, gamma ray and HCP irradiations. • The origins of the reduction in RPL efficiency are investigated and discussed.

  13. Fluorescent nuclear track images of Ag-activated phosphate glass irradiated with photons and heavy charged particles

    International Nuclear Information System (INIS)

    Kurobori, Toshio; Yanagida, Yuka; Kodaira, Satoshi; Shirao, Taichi

    2017-01-01

    In this paper we report about the demonstration of the nuclear track imaging capabilities of Ag-activated phosphate glass. A 375 nm laser and confocal laser scanning microscopy (CLSM) were respectively used for track excitation and detection. Specifically, the blue and orange radiophotoluminescent (RPL) tracks and dose distributions observed after irradiation with soft X-rays, gamma rays and heavy charged particles (HCPs) are examined. In addition, the origins of the reductions in RPL efficiency for high-dose X-ray irradiation and for irradiation with HCPs with high linear energy transfer (LET) values are investigated via a CLSM and a conventional fluorescent reader and discussed. - Highlights: • 3D track images are demonstrated using a confocal laser microscopy. • Fluorescent track detectors are based on RPL Ag-doped phosphate glass. • The dose distributions are examined for X-ray, gamma ray and HCP irradiations. • The origins of the reduction in RPL efficiency are investigated and discussed.

  14. HTCAP: a FORTRAN IV program for calculating coated-particle operating temperatures in HFIR target irradiation experiments

    International Nuclear Information System (INIS)

    Kania, M.J.

    1976-05-01

    A description is presented of HTCAP, a computer code that calculates in-reactor operating temperatures of loose coated ThO 2 particles in the HFIR target series of irradiation tests. Three computational models are employed to determine the following: (1) fission heat generation rates, (2) capsule heat transfer analysis, and (3) maximum particle surface temperature within the design of an HT capsule. Maximum particle operating temperatures are calculated at daily intervals during each irradiation cycle. The application of HTCAP to sleeve CP-62 of HT-15 is discussed, and the results are compared with those obtained in an earlier thermal analysis on the same capsule. Agreement is generally within +-5 percent, while decreasing the computational time by more than an order of magnitude. A complete FORTRAN listing and summary of required input data are presented in appendices. Included is a listing of the input data and a tabular output from the thermal analysis of sleeve CP-62 of HT-15

  15. Pre- and post-irradiation characterization and properties measurements of ZrC coated surrogate TRISO particles

    Energy Technology Data Exchange (ETDEWEB)

    Vasudevamurthy, Gokul [ORNL; Katoh, Yutai [ORNL; Hunn, John D [ORNL; Snead, Lance Lewis [ORNL

    2010-09-01

    Zirconium carbide is a candidate to either replace or supplement silicon carbide as a coating material in TRISO fuel particles for high temperature gas-cooled reactor fuels. Six sets of ZrC coated surrogate microsphere samples, fabricated by the Japan Atomic Energy Agency using the fluidized bed chemical vapor deposition method, were irradiated in the High Flux Isotope Reactor at the Oak Ridge National Laboratory. These developmental samples available for the irradiation experiment were in conditions of either as-fabricated coated particles or particles that had been heat-treated to simulate the fuel compacting process. Five sets of samples were composed of nominally stoichiometric compositions, with the sixth being richer in carbon (C/Zr = 1.4). The samples were irradiated at 800 and 1250 C with fast neutron fluences of 2 and 6 dpa. Post-irradiation, the samples were retrieved from the irradiation capsules followed by microstructural examination performed at the Oak Ridge National Laboratory's Low Activation Materials Development and Analysis Laboratory. This work was supported by the US Department of Energy Office of Nuclear Energy's Advanced Gas Reactor program as part of International Nuclear Energy Research Initiative collaboration with Japan. This report includes progress from that INERI collaboration, as well as results of some follow-up examination of the irradiated specimens. Post-irradiation examination items included microstructural characterization, and nanoindentation hardness/modulus measurements. The examinations revealed grain size enhancement and softening as the primary effects of both heat-treatment and irradiation in stoichiometric ZrC with a non-layered, homogeneous grain structure, raising serious concerns on the mechanical suitability of these particular developmental coatings as a replacement for SiC in TRISO fuel. Samples with either free carbon or carbon-rich layers dispersed in the ZrC coatings experienced negligible grain size

  16. Pancreatic PEComa: a case report with ultrastructural localization of HMB-45 within melanosomes.

    Science.gov (United States)

    Finzi, Giovanna; Micello, Donata; Wizemann, Giorgio; Sessa, Fausto; Capella, Carlo

    2012-04-01

    PEComas (perivascular epithelioid cell tumors) represent a group of mesenchymal neoplasms showing characteristic morphologic, immunohistochemical, ultrastructural, and genetic features. These neoplasms are usually considered benign, being often well circumscribed by a thin capsule and showing scarce atypia. However, in some cases, they show local invasion and multiple metastases and cause the patient's death. PEComas have been found in many locations, but only 7 cases have been described in the pancreas to date. Here, the authors report an additional case of this rare neoplasm and demonstrate the HMB-45 immunoreactivity of melanosomes or premelanosomes at the ultrastructural level.

  17. Radiation and biophysical studies on cells and viruses. Progress report 1 July 1977--30 June 1978. [Particle beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Cole, Arthur; Ansevin, Allen T.; Corry, Peter M.

    1978-08-01

    Studies on genetic structure included arrangement of interphase and mitotic chromosomes, nucleoproteins, and DNA. Studies on analysis of sensitive sites by particle beam irradiation included location of cellular sites for mutation induction and cell transformation. Studies on radiation damage and repair and radiation as an investigative tool included damage to nuclear proteins and other model systems; detection and quantitation of cell surface antigens; interaction of hyperthermia and irradiation; radioinduced cell transformation alkaline elution studies of damage and repair; and low dose, low LET lethality. (HLW)

  18. Contaminant degradation by irradiated semiconducting silver chloride particles: kinetics and modelling.

    Science.gov (United States)

    Ma, Tian; Garg, Shikha; Miller, Christopher J; Waite, T David

    2015-05-15

    The kinetics and mechanism of light-mediated formic acid (HCOO(-)) degradation in the presence of semiconducting silver chloride particles are investigated in this study. Our experimental results show that visible-light irradiation of AgCl(s) results in generation of holes and electrons with the photo-generated holes and its initial oxidation product carbonate radical, oxidizing HCOO(-) to form CO2. The HCOO(-) degradation rate increases with increase in silver concentration due to increase in rate of photo-generation of holes while the increase in chloride concentration decreases the degradation rate of HCOO(-) as a result of the scavenging of holes by Cl(-), thereby resulting in decreased holes and carbonate radical concentration. The results obtained indicate that a variety of other solution conditions including dioxygen concentration, bicarbonate concentration and pH influence the availability of holes and hence the HCOO(-) degradation rate in a manner consistent with our understanding of key processes. Based on our experimental results, we have developed a kinetic model capable of predicting AgCl(s)-mediated HCOO(-) photo-degradation over a wide range of conditions. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Ultra-high vacuum target assembly for charged particle irradiations in the materials research field

    International Nuclear Information System (INIS)

    Bressers, J.; Cassanelli, G.; Cat, R. de; Kohnen, H.; Gherardi, G.

    1978-01-01

    A target assembly designed for ion irradiation and ion implantation experiments on different particle accelerators is described. It consists of a target chamber separated from the beam line by a thin metal window, thus allowing implantations to be carried out under ultra-high vacuum conditions. Homogeneous in-depth distribution of the implanted ion species is realized by rotating the target about an axis perpendicular to the ion beam (rocking). The target holder is driven by means of a stepping motor with a constant step angle and a rocking device controller containing the required rocking angle-dwell time relation. Ion beam homogeneity over a sufficiently large target area is arrived at by transforming the Gaussian beam intensity profile into a flat beam intensity distribution by means of an electrostatic ring lens. The beam intensity profile is monitored by means of a specially designed ion beam monitor based on the Nipkov disc principle. A toroidal beam current monitoring transformer continuously measures the total beam current. Beam scanners and current measuring collimators complete the beam analysing equipment

  20. Development of elemental technique for single particle irradiation system to cell

    International Nuclear Information System (INIS)

    Yukawa, Masae; Yasuda, Nakahiro; Matsumoto, Kenichi

    2004-01-01

    A single-ion microbeam facility (SPICE: Single Particle Irradiation system to Cell) are constructing at National Institute of Radiological Sciences (NIRS). The system was design to deliver the defined number of helium or hydrogen ions into an area smaller than the nuclei of cells in culture on thin films. The beam will be focused into 2μmθ (in diameter) by triplet-Q magnet. We have established the monitoring system using thin plastic scintillator, IIT and charge-coupled device (CCD) camera to measure the size and position of microbeam. The monitoring system for microbeam has been evaluated in the middle energy course using 4.3 MeV protons. We have designed and made two new type collimators to get the microbeam, and have evaluated its scattering effect. We have confirmed that the collimated beam spot (100 ions/sec) was observed in CCD image as small light spot. This system is now installed into SPICE apparatus. (authors)

  1. The effect of charge collection recovery in silicon p-n junction detectors irradiated by different particles

    International Nuclear Information System (INIS)

    Verbitskaya, E.; Abreu, M.; Anbinderis, P.; Anbinderis, T.; D'Ambrosio, N.; Boer, W. de; Borchi, E.; Borer, K.; Bruzzi, M.; Buontempo, S.; Casagrande, L.; Chen, W.; Cindro, V.; Dezillie, B.; Dierlamm, A.; Eremin, V.; Gaubas, E.; Gorbatenko, V.; Granata, V.; Grigoriev, E.; Grohmann, S.; Hauler, F.; Heijne, E.; Heising, S.; Hempel, O.; Herzog, R.; Haerkoenen, J.; Ilyashenko, I.; Janos, S.; Jungermann, L.; Kalesinskas, V.; Kapturauskas, J.; Laiho, R.; Li, Z.; Mandic, I.; De Masi, Rita; Menichelli, D.; Mikuz, M.; Militaru, O.; Niinikoski, T.O.; O'Shea, V.; Pagano, S.; Palmieri, V.G.; Paul, S.; Perea Solano, B.; Piotrzkowski, K.; Pirollo, S.; Pretzl, K.; Rato Mendes, P.; Ruggiero, G.; Smith, K.; Sonderegger, P.; Sousa, P.; Tuominen, E.; Vaitkus, J.; Da Via, C.; Wobst, E.; Zavrtanik, M.

    2003-01-01

    The recovery of the charge collection efficiency (CCE) at low temperatures, the so-called 'Lazarus effect', was studied in Si detectors irradiated by fast reactor neutrons, by protons of medium and high energy, by pions and by gamma-rays. The experimental results show that the Lazarus effect is observed: (a) after all types of irradiation; (b) before and after space charge sign inversion; (c) only in detectors that are biased at voltages resulting in partial depletion at room temperature. The experimental temperature dependence of the CCE for proton-irradiated detectors shows non-monotonic behaviour with a maximum at a temperature defined as the CCE recovery temperature. The model of the effect for proton-irradiated detectors agrees well with that developed earlier for detectors irradiated by neutrons. The same midgap acceptor-type and donor-type levels are responsible for the Lazarus effect in detectors irradiated by neutrons and by protons. A new, abnormal 'zigzag'-shaped temperature dependence of the CCE was observed for detectors irradiated by all particles (neutrons, protons and pions) and by an ultra-high dose of γ-rays, when operating at low bias voltages. This effect is explained in the framework of the double-peak electric field distribution model for heavily irradiated detectors. The redistribution of the space charge region depth between the depleted regions adjacent to p + and n + contacts is responsible for the 'zigzag'- shaped curves. It is shown that the CCE recovery temperature increases with reverse bias in all detectors, regardless of the type of radiation

  2. Advanced Electron Microscopy and Micro analytical technique development and application for Irradiated TRISO Coated Particles from the AGR-1 Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Van Rooyen, Isabella Johanna [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lillo, Thomas Martin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wen, Haiming [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wright, Karen Elizabeth [Idaho National Lab. (INL), Idaho Falls, ID (United States); Madden, James Wayne [Idaho National Lab. (INL), Idaho Falls, ID (United States); Aguiar, Jeffery Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-01-01

    A series of up to seven irradiation experiments are planned for the Advanced Gas Reactor (AGR) Fuel Development and Quantification Program, with irradiation completed at the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) for the first experiment (i.e., AGR-1) in November 2009 for an effective 620 full power days. The objective of the AGR-1 experiment was primarily to provide lessons learned on the multi-capsule test train design and to provide early data on fuel performance for use in fuel fabrication process development and post-irradiation safety testing data at high temperatures. This report describes the advanced microscopy and micro-analysis results on selected AGR-1 coated particles.

  3. Structural and morphological changes in pseudobarrier films of anodic aluminum oxide caused by irradiation with high-energy particles

    International Nuclear Information System (INIS)

    Chernykh, M.A.; Belov, V.T.

    1988-01-01

    We have studied the structural and morphological changes, occurring under the electron beam in pseudobarrier films of anodic aluminum oxide, prepared in seven different solutions and irradiated beforehand by protons of x-rays, with the aim of elucidating the structure of anodic aluminum oxides. An increased stability of the pseudobarrier films of anodic aluminum oxide has been observed towards the action of the electron beam of an UEMV-100K microscope at standard working regimes (75 keV) as a result of irradiation with protons or x-rays. A difference has been found to exist between structural and morphological changes of anodic aluminum oxide films, prepared in different solutions, when irradiated with high-energy particles. A structural and phase inhomogeneity of amorphous pseudobarrier films of anodic aluminum oxide has been detected and its influence on the character of solid-phase transformations under the maximum-intensity electron beam

  4. Electron Microscopic Examination of Irradiated TRISO Coated Particles of Compact 6-3-2 of AGR-1 Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Van Rooyen, Isabella Johanna [Idaho National Lab. (INL), Idaho Falls, ID (United States); Demkowicz, Paul Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States); Riesterer, Jessica Lori [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, Brandon Douglas [Idaho National Lab. (INL), Idaho Falls, ID (United States); Janney, Dawn Elizabeth [Idaho National Lab. (INL), Idaho Falls, ID (United States); Harp, Jason Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ploger, Scott Arden [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2012-12-01

    The electron microscopic examination of selected irradiated TRISO coated particles of the AGR-1 experiment of fuel compact 6-3-2 are presented in this report. Compact 6-3-2 refers to the compact in Capsule 6 at level 3 of Stack 2. The fuel used in capsule 6 compacts, are called the “baseline” fuel as it is fabricated with refined coating process conditions used to fabricate historic German fuel, because of its excellent irradiation performance with UO2 kernels. The AGR-1 fuel is however made of low-enriched uranium oxycarbide (UCO). Kernel diameters are approximately 350 µm with a U-235 enrichment of approximately 19.7%. Compact 6-3-2 has been irradiated to 11.3% FIMA compact average burn-up with a time average, volume average temperature of 1070.2°C and with a compact average fast fluence of 2.38E21 n/cm

  5. Response of Ni/4H-SiC Schottky barrier diodes to alpha-particle irradiation at different fluences

    Energy Technology Data Exchange (ETDEWEB)

    Omotoso, E., E-mail: ezekiel.omotoso@up.ac.za [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa); Departments of Physics, Obafemi Awolowo University, Ile-Ife 220005 (Nigeria); Meyer, W.E.; Auret, F.D.; Diale, M.; Ngoepe, P.N.M. [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa)

    2016-01-01

    Irradiation experiments have been carried out on 1.9×10{sup 16} cm{sup −3} nitrogen-doped 4H-SiC at room temperature using 5.4 MeV alpha-particle irradiation over a fluence ranges from 2.6×10{sup 10} to 9.2×10{sup 11} cm{sup −2}. Current–voltage (I–V), capacitance–voltage (C–V) and deep level transient spectroscopy (DLTS) measurements have been carried out to study the change in characteristics of the devices and free carrier removal rate due to alpha-particle irradiation, respectively. As radiation fluence increases, the ideality factors increased from 1.20 to 1.85 but the Schottky barrier height (SBH{sub I–V}) decreased from 1.47 to 1.34 eV. Free carrier concentration, N{sub d} decreased with increasing fluence from 1.7×10{sup 16} to 1.1×10{sup 16} cm{sup −2} at approximately 0.70 μm depth. The reduction in N{sub d} shows that defects were induced during the irradiation and have effect on compensating the free carrier. The free carrier removal rate was estimated to be 6480±70 cm{sup −1}. Alpha-particle irradiation introduced two electron traps (E{sub 0.39} and E{sub 0.62}), with activation energies of 0.39±0.03 eV and 0.62±0.08 eV, respectively. The E{sub 0.39} as attribute related to silicon or carbon vacancy, while the E{sub 0.62} has the attribute of Z{sub 1}/Z{sub 2}.

  6. Behavior of LASL-made graphite, ZrC, and ZrC-containing coated particles in irradiation tests HT-28 and HT-29

    International Nuclear Information System (INIS)

    Reiswig, R.D.; Wagner, P.; Hollabaugh, C.M.; White, R.W.; O'Rourke, J.A.; Davidson, K.V.; Schell, D.H.

    1976-01-01

    Three types of materials, extruded graphite, hot-pressed ZrC, and particles with ZrC coatings, were irradiated in ORNL High Fluence Isotope Reactor Irradiation tests HT-28 and HT-29. The ZrC seemed unaffected. The graphite changed in dimensions, x-ray diffraction parameters, and thermal conductivity. The four types of coated particles tested all resisted the irradiation well, except one set of particles with double-graded C-ZrC-C coats. Overall, the results were considered encouraging for use of ZrC and extruded graphite fuel matrices. 16 fig

  7. Differences in the melanosome distribution within the epidermal melanin units and its association with the impairing background of leukoderma in vitiligo and halo nevi: a retrospective study.

    Science.gov (United States)

    Xiong, Xi-Xi; Ding, Gao-Zhong; Zhao, Wen-E; Li, Xue; Ling, Yu-Ting; Sun, Li; Gong, Qing-Li; Lu, Yan

    2017-07-01

    Skin color is determined by the number of melanin granules produced by melanocytes that are transferred to keratinocytes. Melanin synthesis and the distribution of melanosomes to keratinocytes within the epidermal melanin unit (EMU) within the skin of vitiligo patients have been poorly studied. The ultrastructure and distribution of melanosomes in melanocytes and surrounding keratinocytes in perilesional vitiligo and normal skin were investigated using transmission electron microscopy (TEM). Furthermore, we performed a quantitative analysis of melanosome distribution within the EMUs with scatter plot. Melanosome count within keratinocytes increased significantly compared with melanocytes in perilesional stable vitiligo (P vitiligo. Furthermore, melanosome counts within melanocytes and their surrounding keratinocytes in perilesional active vitiligo skin decreased significantly compared with the other groups. In addition, taking the means-standard error of melanosome count within melanocytes and keratinocytes in healthy controls as a normal lower limit, EMUs were graded into 3 stages (I-III). Perilesional active vitiligo presented a significantly different constitution in stages compared to other groups (P vitiligo. Active vitiligo varies in stages and in stage II, EMUs are slightly impaired, but can be resuscitated, providing a golden opportunity with the potential to achieve desired repigmentation with an appropriate therapeutic choice. Adverse milieu may also contribute to the low melanosome count in keratinocytes.

  8. Device for irradiation with electron and a magnetic lens for deviation of beams of charged particles, especially electrons

    International Nuclear Information System (INIS)

    Anderberg, B.

    1990-01-01

    An electron beam is sweeping aver the object while this is moved forward. In order to achieve a uniform irradiation and compensate for geometric errors, an additional magnetic lens is located immediately beneath the exposed area. The magnetic lens refract the electron beam in such a manner that the particle trajectories become parallel or slightly convergent after the lens. The lens consists of two parallel permanent bar magnets, preferably laminated magnets. (L.F.)

  9. Theoretical and experimental radiation effectiveness of the free radical dosimeter alanine to irradiation with heavy charged particles

    DEFF Research Database (Denmark)

    Hansen, Jørgen-Walther; Olsen, K. J.

    1985-01-01

    Dose-response characteristics have been measured for the crystalline amino acid L-.alpha.-alanine irradiated with ion beams of 6 and 16 MeV protons, 20 MeV .alpha. particles, 21 MeV7Li ions, 64 MeV16O ions, and 80 MeV32S ions. The experimental radiation effectiveness (RE) with reference to low-LE...

  10. Alpha-particle irradiation induced defects in SiO2 films of Si-SiO2 structures

    International Nuclear Information System (INIS)

    Koman, B.P.; Gal'chynskyy, O.V.; Kovalyuk, R.O.; Shkol'nyy, A.K.

    1996-01-01

    The aim of the work was to investigate alpha-particle irradiation induced defects in Si-SiO 2 structures by means of the thermostimulated discharge currents (TSDC) analysis. The object of investigation were (p-Si)-SiO 2 structures formed by a combined oxidation of the industrial p-Si wafers in dry and wet oxygen at temperature of 1150 C. The TSD currents were investigated in the temperature range between 90 and 500 K under linear heating rate. Pu 238 isotopes were the source of alpha-particles with an energy of 4-5 MeV and a density of 5.10 7 s -1 cm -2 . The TSD current curves show two peculiar maxima at about 370 and 480 K. Alpha-particle irradiation doesn't affect the general shape of the TSDC curves but leads to a shift of the maximum at 370 K and reduces the total electret charge which is accumulated in the Si-SiO 2 structures during polarization. The energy distribution function of the defects which are involved in SiO 2 polarization has been calculated. It showes that defects with activation energies of about 0.8 and 1.0 eV take part in forming the electret state, and these activation energies have certain energy distributions. It has been found that the TSDC maximum at 370 K has space charge nature and is caused by migration of hydrogen ions. In irradiated samples hydrogen and natrium ions localize on deeper trapping centres induced by alpha-particle irradiation. (orig.)

  11. A role for Na+,K+-ATPase α1 in regulating Rab27a localisation on melanosomes.

    Directory of Open Access Journals (Sweden)

    Antonia E G Booth

    Full Text Available The mechanism(s by which Rab GTPases are specifically recruited to distinct intracellular membranes remains elusive. Here we used Rab27a localisation onto melanosomes as a model to investigate Rab targeting. We identified the α1 subunit of Na+,K+-ATPase (ATP1a1 as a novel Rab27a interacting protein in melanocytes and showed that this interaction is direct with the intracellular M4M5 loop of ATP1a1 and independent of nucleotide bound status of the Rab. Knockdown studies in melanocytes revealed that ATP1a1 plays an essential role in Rab27a-dependent melanosome transport. Specifically, expression of ATP1a1, like the Rab27a GDP/GTP exchange factor (Rab3GEP, is essential for targeting and activation of Rab27a to melanosomes. Finally, we showed that the ability of Rab27a mutants to target to melanosomes correlates with the efficiency of their interaction with ATP1a1. Altogether these studies point to a new role for ATP1a1 as a regulator of Rab27a targeting and activation.

  12. Effects of fuel particle size and fission-fragment-enhanced irradiation creep on the in-pile behavior in CERCER composite pellets

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yunmei [Institute of Mechanics and Computational Engineering, Department of Aeronautics and Astronautics, Fudan University, Shanghai 200433 (China); Ding, Shurong, E-mail: dsr1971@163.com [Institute of Mechanics and Computational Engineering, Department of Aeronautics and Astronautics, Fudan University, Shanghai 200433 (China); Zhang, Xunchao; Wang, Canglong; Yang, Lei [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2016-12-15

    The micro-scale finite element models for CERCER pellets with different-sized fuel particles are developed. With consideration of a grain-scale mechanistic irradiation swelling model in the fuel particles and the irradiation creep in the matrix, numerical simulations are performed to explore the effects of the particle size and the fission-fragment-enhanced irradiation creep on the thermo-mechanical behavior of CERCER pellets. The enhanced irradiation creep effect is applied in the 10 μm-thick fission fragment damage matrix layer surrounding the fuel particles. The obtained results indicate that (1) lower maximum temperature occurs in the cases with smaller-sized particles, and the effects of particle size on the mechanical behavior in pellets are intricate; (2) the first principal stress and radial axial stress remain compressive in the fission fragment damage layer at higher burnup, thus the mechanism of radial cracking found in the experiment can be better explained. - Highlights: • A grain-scale gas swelling model considering the development of recrystallization and resolution is adopted for particles. • The influence of fission-gas-induced porosity is considered in the constitutive relations for particles. • A simulation method is developed for the multi-scale thermo-mechanical behavior. • The effects of fuel particle size and fission-fragment-enhanced irradiation creep are investigated in pellets.

  13. Mechanical properties and the evolution of matrix molecules in PTFE upon irradiation with MeV alpha particles

    International Nuclear Information System (INIS)

    Fisher, Gregory L.; Lakis, Rollin E.; Davis, Charles C.; Szakal, Christopher; Swadener, John G.; Wetteland, Christopher J.; Winograd, Nicholas

    2006-01-01

    The morphology, chemical composition, and mechanical properties in the surface region of α-irradiated polytetrafluoroethylene (PTFE) have been examined and compared to unirradiated specimens. Samples were irradiated with 5.5 MeV 4 He 2+ ions from a tandem accelerator to doses between 1 x 10 6 and 5 x 10 10 Rad. Static time-of-flight secondary ion mass spectrometry (ToF-SIMS), using a 20 keV C 60 + source, was employed to probe chemical changes as a function of α dose. Chemical images and high resolution spectra were collected and analyzed to reveal the effects of α particle radiation on the chemical structure. Residual gas analysis (RGA) was utilized to monitor the evolution of volatile species during vacuum irradiation of the samples. Scanning electron microscopy (SEM) was used to observe the morphological variation of samples with increasing α particle dose, and nanoindentation was engaged to determine the hardness and elastic modulus as a function of α dose. The data show that PTFE nominally retains its innate chemical structure and morphology at α doses 9 Rad. At α doses ≥10 9 Rad the polymer matrix experiences increased chemical degradation and morphological roughening which are accompanied by increased hardness and declining elasticity. At α doses >10 10 Rad the polymer matrix suffers severe chemical degradation and material loss. Chemical degradation is observed in ToF-SIMS by detection of ions that are indicative of fragmentation, unsaturation, and functionalization of molecules in the PTFE matrix. The mass spectra also expose the subtle trends of crosslinking within the α-irradiated polymer matrix. ToF-SIMS images support the assertion that chemical degradation is the result of α particle irradiation and show morphological roughening of the sample with increased α dose. High resolution SEM images more clearly illustrate the morphological roughening and the mass loss that accompanies high doses of α particles. RGA confirms the supposition that

  14. Synthesis of gold nano particles with enlargement size by gamma Co-60 irradiation and investigation of anti oxidation effect

    International Nuclear Information System (INIS)

    Nguyen Ngoc Duy; Dang Van Phu; Le Anh Quoc; Nguyen Quoc Hien

    2014-01-01

    Gold nanoparticles (AuNPs) with size in the range of 10-53 nm were synthesized by gamma Co-60 irradiation using water-soluble chitosan (WSC) as stabilizer and size enlargement by seed approach. Absorption wavelength (λ max ) was measured by UV-Vis spectroscopy and particle size was determined from TEM images. Results showed that value of λ max increased from 523 nm (seed particles) to 525, 537 and 549 nm and the size of AuNPs increased from 10 nm (seed particles) to 20, 38 and 53 nm, respectively, for concentration ratio of Au 3+ /Au 0 (seed) of 2.5, 5 and 10. Antioxidant effect of AuNPs with size of 10, 20, 38 and 53 nm was investigated using free radical 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS .+ ). Results indicated that the smaller the particle size was (10 nm) the stronger the antioxidant effect attained. Thus, AuNPs/WSC synthesis by gamma Co-60 irradiation are promising for applications as antioxidants in cosmetics and in other fields as well. (author)

  15. Expression profiling of murine lung 70 days following exposure to fractionated or acute dose of 1.0 Gy 56Fe- particle irradiation

    Data.gov (United States)

    National Aeronautics and Space Administration — Irradiation of the K-rasLA1 mouse model with a fractionated dose of 1.0Gy 56Fe- particles increases the incidence of invasive carcinoma compared to unirradiated...

  16. AFM of metallic nano-particles and nano-structures in heavily irradiated NaCl

    NARCIS (Netherlands)

    Gaynutdinov, R; Vainshtein, DI; Hak, SJ; Tolstikhina, A; Den Hartog, HW

    2003-01-01

    AFM investigations are reported for heavily, electron irradiated NaCl crystals in ultra high vacuum (UHV) in the non-contact mode-with an UHV AFM/STM Omicron system. To avoid chemical reactions between the radiolytic Na and oxygen and water, the irradiated samples were cleaved and prepared for the

  17. The effects of intense gamma-irradiation on the alpha-particle response of silicon carbide semiconductor radiation detectors

    International Nuclear Information System (INIS)

    Ruddy, Frank H.; Seidel, John G.

    2007-01-01

    Silicon Carbide (SiC) semiconductor radiation detectors are being developed for alpha-particle, X-ray and Gamma-ray, and fast-neutron energy spectrometry. SiC detectors have been operated at temperatures up to 306 deg. C and have also been found to be highly resistant to the radiation effects of fast-neutron and charged-particle bombardments. In the present work, the alpha-particle response of a SiC detector based on a Schottky diode design has been carefully monitored as a function of 137 Cs gamma-ray exposure. The changes in response have been found to be negligible for gamma exposures up to and including 5.4 MGy, and irradiations to higher doses are in progress

  18. GIF++: A new CERN Irradiation Facility to test large-area particle detectors for the High-Luminosity LHC program

    CERN Document Server

    Guida, Roberto

    2016-01-01

    The high-luminosity LHC (HL-LHC) upgrade is setting a new challenge for particle detector technologies. The increase in luminosity will produce a higher particle background with respect to present conditions. To study performance and stability of detectors at LHC and future HL-LHC upgrades, a new dedicated facility has been built at CERN: the new Gamma Irradiation Facility (GIF++). The GIF++ is a unique place where high energy charged particle beams (mainly muons) are combined with gammas from a 14 TBq 137Cesium source which simulates the background radiation expected at the LHC experiments. Several centralized services and infrastructures are made available to the LHC detector community to facilitate the different R&D; programs.

  19. Investigation of double strand breaks induced by alpha particle irradiation using C.N.B.G. microbeam in human keratinocytes

    International Nuclear Information System (INIS)

    Pouthier, Th.

    2006-12-01

    To understand the mechanisms of interaction of ionizing radiation with living tissues exposed to low and protracted doses remains a major issue for risk evaluation. The response cannot be found in epidemiological studies because the only available data concern accidental exposures to high doses of radiation. The natural exposure represents the main source of exposure in the daily life, just before the medical sources (radiology, radiotherapy). In addition, this kind of exposure is very difficult to reproduce in vitro by irradiating cell lines. The method per preference is based on random irradiation of cell populations. The mean number of particles having traversed cells is then calculated on the basis of Poisson statistics. In addition to inevitable multiple impacts, the numerous potential intracellular targets (nuclei, cytoplasm), the indirect effects induced by the impact of particles on neighbouring cells or simply the extracellular targets, constitute phenomena that make more complex the interpretation of experimental data. A charged particle microbeam was developed at C.E.N.B.G. to perform the targeted irradiation of individual cells with a targeting precision of a few microns. It is possible to deliver a counted number of alpha particles down to the ultimate dose of one alpha per cell, to target predetermined cells and then to observe the response of the neighbouring cells. This facility has been validated during this work on human keratinocyte cells expressing a recombinant nuclear fluorescent protein (histone H2B-GFP). The combination of ion micro-beams with confocal microscopy and numeric quantitative analysis allowed the measurement of DNA double strand breaks via the phosphorylation of the histone H2A.X in individual cells. The mechanisms of DNA reparation and apoptosis induction were also in the scope of those studies. The experimental results obtained during this thesis validate the methodology we have developed by demonstrating the targeting

  20. Development of a High Irradiance LED Configuration for Small Field of View Motion Estimation of Fertilizer Particles

    Directory of Open Access Journals (Sweden)

    Simon Cool

    2015-11-01

    Full Text Available Better characterization of the fertilizer spreading process, especially the fertilizer pattern distribution on the ground, requires an accurate measurement of individual particle properties and dynamics. Both 2D and 3D high speed imaging techniques have been developed for this purpose. To maximize the accuracy of the predictions, a specific illumination level is required. This paper describes the development of a high irradiance LED system for high speed motion estimation of fertilizer particles. A spectral sensitivity factor was used to select the optimal LED in relation to the used camera from a range of commercially available high power LEDs. A multiple objective genetic algorithm was used to find the optimal configuration of LEDs resulting in the most homogeneous irradiance in the target area. Simulations were carried out for different lenses and number of LEDs. The chosen configuration resulted in an average irradiance level of 452 W/m2 with coefficient of variation less than 2%. The algorithm proved superior and more flexible to other approaches reported in the literature and can be used for various other applications.

  1. AFM of metallic nano-particles and nano-structures in heavily irradiated NaCl

    OpenAIRE

    Gaynutdinov, R; Vainshtein, DI; Hak, SJ; Tolstikhina, A; Den Hartog, HW

    2003-01-01

    AFM investigations are reported for heavily, electron irradiated NaCl crystals in ultra high vacuum (UHV) in the non-contact mode-with an UHV AFM/STM Omicron system. To avoid chemical reactions between the radiolytic Na and oxygen and water, the irradiated samples were cleaved and prepared for the experiments in UHV At the surface of freshly cleaved samples, we have observed sodium nano-precipitates with shapes, which depend on the irradiation dose and the volume fraction of the radiolytic Na...

  2. Coloration and darkening of methane clathrate and other ices by charged particle irradiation - Applications to the outer solar system

    Science.gov (United States)

    Thompson, W. Reid; Murray, B. G. J. P. T.; Khare, B. N.; Sagan, Carl

    1987-01-01

    The results of laboratory experiments simulating the irradiation of hydrocarbon-H2O or hydrocarbon-H2O/NH3 clathrates by charged particles in the outer solar system are reported. Ices produced by condensing and boiling liquid CH4 on an H2O frost surface at 100 K or by cocondensing frosts from gaseous mixtures were exposed to coronal-discharge electron irradiation at 77 K, and the spectral properties of the irradiated surfaces were determined. Significant darkening of the initially white ices was observed at doses of 1 Gerg/sq cm, corresponding to 8-500 yrs of irradiation by Uranian magnetospheric electrons on the surfaces of the principal Uranian satellites, or to total destruction of CH4 in the upper 1 mm of the satellite surfaces after 0.05-3.0 Myr. It is estimated that 10 m or more of icy satellite or comet surfaces would be radiation-hardened to a CH4-free ice-tholin mixture over 4 Gyr.

  3. Synthesis of diamondlike carbon particles in/on a water substrate by laser irradiation

    International Nuclear Information System (INIS)

    Hidai, Hirofumi; Tokura, Hitoshi

    2005-01-01

    We proposed two-particle synthesis techniques using a liquid as a substrate. First, utilizing liquid instead of solid substrates, particle synthesis is expected on the liquid surface. Particles sink into the liquid before the particles grow into film, because of liquid fluidity. Second, the excitation of a gas dissolved in water was also attempted. An ArF excimer laser beam was focused in a chamber. The 60% volume of the chamber was filled with water, in which methane was dissolved and the remaining space of the chamber was filled with methane gas. As a result, diamondlike carbon particles could be synthesized in water. The particles synthesized from methane in the gas phase were 50-200 nm in diameter, and the particles synthesized from methane dissolved in water were 200-700 nm in diameter, and no structural differences were observed between the particles of two different diameters. Energy-dispersive spectroscopy, Raman spectroscopy analysis, and high-resolution transmission electron microscopy observations revealed that particles contained a diamondlike carbon component and that graphite was attached to them. These particles were harder than graphite particles

  4. Effects of α-particle beam irradiation on superconducting properties of thin film MgB2 superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Bum; Duong, Pham van; Ha, Dong Hyup; Oh, Young Hoon; Kang, Won Nam; Chai, Jong Seo [Sungkunkwan Univeversity, Suwon (Korea, Republic of); Hong, Seung Pyo; Kim, Ran Young [Kore Institute of Radiological and Medical Science, Seoul (Korea, Republic of)

    2016-06-15

    Superconducting properties of thin film MgB2 superconductors irradiated with 45 MeV α-particle beam were studied. After the irradiation, enhancement of the critical current density and pinning force was observed, scaling close to strong pinning formula. Double logarithmic plots of the maximum pinning force density with irreversible magnetic field show a power law behavior close to carbon-doped MgB2 film or polycrystals. Variation of normalized pinning force density in the reduced magnetic field suggests scaling formulas for strong pinning mechanism like planar defects. We also observed a rapid decay of critical current density as the vortex lattice constant decreases, due to the strong interaction between vortices and increasing magnetic field.

  5. Growth and sedimentation of fine particles produced in aqueous solutions of palladium sulfate and palladium sulfate-silver sulfate induced by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Hatada, Motoyoshi; Jonah, C.D.

    1994-10-01

    It is known that palladium and palladium-silver fine particles were formed from deaerated aqueous solutions of palladium sulfate and palladium sulfate-silver sulfate induced by gamma-ray irradiation. Changes in particle size and with amount of particles in the solution with time during and after irradiation were studied using dynamic light scattering technique and UV spectrophotometer. The particles formed from palladium sulfate solution are found to be water-filled bulky particles of diameter of 200 nm, which grow by mutual coagulation even after irradiation was terminated. Average density depends on concentration of palladium ion in the solution and dose, and the lowest density was about 2 g/cm 3 for particles of 200 nm obtained from 0.06 mM solution by 2.4 kGy irradiation. The average density of the particles obtained from palladium sulfate-silver sulfate solutions was smaller than those obtained for the corresponding palladium sulfate solutions. Supersonic agitation destroyed coagulated precipitates to form fine particles, but did not form clusters of a few atoms. (author)

  6. The use of gamma irradiation in preparation of polybutadiene rubber nanopowder; Its effect on particle size, morphology and crosslink structure of the powder

    Energy Technology Data Exchange (ETDEWEB)

    Rezaei Abadchi, Majid; Jalali-Arani, Azam, E-mail: ajalali@aut.ac.ir

    2014-02-01

    Highlights: • Vulcanized rubber powders were prepared by spray drying of irradiated rubber latexes. • Influence of absorbed dose on powder structure and characteristics was investigated. • The size of rubber latex particles did not changed by irradiation. • Crosslink density increased by increasing dose and 98% gel was obtained at 150 kGy. • T{sub g} of rubber powder increased with increasing the irradiation dose. -- Abstract: The aim of this work was the preparation and characterization of polybutadiene rubber (BR) powder by irradiating of rubber lattices using {sup 60}Co radiation and spray-drying of them at the appropriate condition. The influences of absorbed dose on the volume swelling ratio, molecular weight between crosslinks, gel fraction, and glass transition temperature of obtained powder were studied. Morphology, size and size distribution of rubber particles were examined by using scanning electron microscopy (SEM) and laser particle size analyzer (LPSA) technique, respectively. Results obtained by LPSA revealed that radiation has no effect on particle size of rubber latex but after drying, adherence properties of rubber particle causes increase in particle size of rubber powder, as shown in SEM photograph. Fourier transform infrared spectroscopy of rubber powders confirmed that with increasing the irradiation dose, characteristic peak corresponds to the >C=C< double bands decreased. Also Charlesby–Pinner equation was used to evaluate radiation yield.

  7. The use of gamma irradiation in preparation of polybutadiene rubber nanopowder; Its effect on particle size, morphology and crosslink structure of the powder

    International Nuclear Information System (INIS)

    Rezaei Abadchi, Majid; Jalali-Arani, Azam

    2014-01-01

    Highlights: • Vulcanized rubber powders were prepared by spray drying of irradiated rubber latexes. • Influence of absorbed dose on powder structure and characteristics was investigated. • The size of rubber latex particles did not changed by irradiation. • Crosslink density increased by increasing dose and 98% gel was obtained at 150 kGy. • T g of rubber powder increased with increasing the irradiation dose. -- Abstract: The aim of this work was the preparation and characterization of polybutadiene rubber (BR) powder by irradiating of rubber lattices using 60 Co radiation and spray-drying of them at the appropriate condition. The influences of absorbed dose on the volume swelling ratio, molecular weight between crosslinks, gel fraction, and glass transition temperature of obtained powder were studied. Morphology, size and size distribution of rubber particles were examined by using scanning electron microscopy (SEM) and laser particle size analyzer (LPSA) technique, respectively. Results obtained by LPSA revealed that radiation has no effect on particle size of rubber latex but after drying, adherence properties of rubber particle causes increase in particle size of rubber powder, as shown in SEM photograph. Fourier transform infrared spectroscopy of rubber powders confirmed that with increasing the irradiation dose, characteristic peak corresponds to the >C=C< double bands decreased. Also Charlesby–Pinner equation was used to evaluate radiation yield

  8. Factors affecting color strength of printing on film-coated tablets by UV laser irradiation: TiO2 particle size, crystal structure, or concentration in the film, and the irradiated UV laser power.

    Science.gov (United States)

    Hosokawa, Akihiro; Kato, Yoshiteru

    2011-08-01

    The purpose of this article is to study factors affecting color strength of printing on film-coated tablets by ultraviolet (UV) laser irradiation: particle size, crystal structure, or concentration of titanium dioxide (TiO2) in film, and irradiated UV laser power. Hydroxypropylmethylcellulose films containing 4.0% of TiO2, of which BET particle sizes were ranging from 126.1 to 219.8 nm, were irradiated 3.14W of UV laser at a wavelength 355 nm to study effects of TiO2 particle size and crystal structure on the printing. The films containing TiO2 concentration ranging from 1.0 to 7.7% were irradiated 3.14 or 5.39W of the UV laser to study effect of TiO2 concentration on the printing. The film containing 4.0% of TiO2, was irradiated the UV laser up to 6.42W to study effect of the UV laser power on the printing. The color strength of the printed films was estimated by a spectrophotometer as total color difference (dE). Particle size, crystal structure, and concentration of TiO2 in the films did not affect the printing. In the relationship between the irradiated UV laser power and dE, there found an inflection point (1.6W). When the UV laser power was below 1.6W, the films were not printed. When it was beyond the point, total color difference increased linearly in proportion with the irradiated laser power. The color strength of the printing on film was not changed by TiO2 particle size, crystal structure, and concentration, but could be controlled by regulating the irradiated UV laser power beyond the inflection point.

  9. Survival of alpha particle irradiated cells as a function of the shape and size of the sensitive volume (nucleus)

    International Nuclear Information System (INIS)

    Stinchcomb, T.G.; Roeske, J.C.

    1995-01-01

    Microdosimetry is the study of the stochastic variation of energy deposited within sub-cellular targets. As such, the size and shape of the critical target (i.e. cell nucleus) are essential when considering microdosimetric quantities. In this work, a microdosimetric analysis examines the expected cell survival as a function of the size and shape of the cell nucleus under conditions of irradiation emitting alpha particles. The results indicate that, in general, cell survival is relatively insensitive to changes in the shape of the cell nucleus when the volume is held constant. However, cell survival is a strong function of the variation in the size of the target. These results are useful when analysing the results of cell survival experiments for alpha particle emitters. (Author)

  10. The sink effect of the second-phase particle on the cavity swelling in RAFM steel under Ar-ion irradiation at 773 K

    International Nuclear Information System (INIS)

    Shen, T.L.; Wang, Z.G.; Yao, C.F.; Sun, J.R.; Li, Y.F.; Wei, K.F.; Zhu, Y.B.; Pang, L.L.; Cui, M.H.; Wang, J.; Zhu, H.P.

    2013-01-01

    The microstructures of the Chinese RAFM steel irradiated at 773 K with 792 MeV Ar-ions to fluences of 2.3 × 10 20 and 4.6 × 10 20 ions/m 2 , respectively, were investigated by using a transmission electron microscope with the cross-sectional specimen technique. Preferential nucleation and enhanced growth of the cavities at the interface between the second-phase particles and the matrix were observed in the irradiated specimen. The observation of the cavity-particle complex at lower dose indicated that the dose threshold for a cavity formation at the interface between MC particle and matrix was lower than that in matrix. With increasing irradiation dose, it was found that the second-phase particles changing their shape by attached cavities occurred. Furthermore, the role of the particle–matrix interface on nucleation and growth of the attached cavity with an increase of the dose were discussed in this work

  11. Promotion of TNF-α on malignant transformation of syrian hamster embryo cells irradiated with α-particles

    International Nuclear Information System (INIS)

    Zhu Maoxiang; Guo Renfeng; Yang Zhihua; GongYifen

    1999-01-01

    Objective: To illustrate the role of tumor necrosis factor-α (TNF-α) in radiation-induced cancer and regulatory mechanism of protein tyrosine phosphorylation. Methods: Taking Syrian hamster embryo cells exposed to 0.5 Gy α-particles as the target, an array of biological indicators such as cell growth curve, transformation frequency (TF), colony formation efficiency (CFE) and tumor formation in nude mice were observed, and the activities of protein tyrosine kinases and protein tyrosine phosphatases were measured. Results: Neither 0.5 Gy α-particle irradiation nor TNF-α alone could induce transformation of SHE cells morphologically, but the TF, CFE and levels of protein tyrosine phosphorylation were obviously increased in SHE cells treated with 600 U/ml TNF-α after exposure to 0.5 Gy α-particles, and malignant transformation was proved by tumorigenicity assays. Conclusion: TNF-α promotes significantly the transformation of SHE cells induced by α-particles, and protein tyrosine phosphorylation is probably involved in regulation of the process

  12. Advanced electron microscopic techniques applied to the characterization of irradiation effects and fission product identification of irradiated TRISO coated particles from the AGR-1 experiment

    International Nuclear Information System (INIS)

    Rooyen, I.J. van; Lillo, T.M.; Trowbridge, T.L.; Madden, J.M.; Wu, Y.Q.; Goran, D.

    2013-01-01

    Preliminary electron microscopy of coated fuel particles from the AGR-1 experiment was conducted using characterization techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and wavelength dispersive spectroscopy (WDS). Microscopic quantification of fission-product precipitates was performed. Although numerous micro- and nano-sized precipitates observed in the coating layers during initial SEM characterization of the cross-sections, and in subsequent TEM diffraction patterns, were indexed as UPd 2 Si 2 , no Ag was conclusively found. Additionally, characterization of these precipitates highlighted the difficulty of measuring low concentrations of Ag in precipitates in the presence of significantly higher concentrations of Pd and U. The electron microscopy team followed a multi-directional and phased approach in the identification of fission products in irradiated TRISO fuel. The advanced electron microscopy techniques discussed in this paper, not only demonstrate the usefulness of the equipment (methods) as relevant research tools, but also provide relevant scientific results which increase the knowledge about TRISO fuel particles microstructure and fission products transport

  13. Structural-morphological variations in pseudo-barrier films of anode aluminium oxide under irradiation with high-energy particles

    International Nuclear Information System (INIS)

    Chernykh, M.A.; Belov, V.T.

    1988-01-01

    Comparative study of structural-morphological variations under electron beam effect in pseudo-barrier films of anode aluminium oxide, obtained in seven different solutions and proton or X-rays pre-irradiated to determine structure peculiarities of anode aluminium oxides, is presented. Such study is a matter of interest from the solid-phase transformation theory point of view and for anode aluminium films application under radiation. Stability increase of pseudo-barrier films of anode aluminium oxide to the effect of UEhMV-100 K microscope electron beam at standard modes of operation (75 kV) due to proton or X-rays irradiation is found. Difference in structural-monorphological variations obtained in different solutions of anode aluminium films under high-energy particles irradiation is determined. Strucural-phase microinhomogeneity of amorphous pseudo-barrier films of anode aluminium oxide and its influence on solid-phase transformations character under electron bean of maximal intensity are detected

  14. Electron Microscopic Examination of Irradiated TRISO Coated Particles of Compact 6-3-2 of AGR-1 Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Van Rooyen, Isabella Johanna [Idaho National Lab. (INL), Idaho Falls, ID (United States); Demkowicz, Paul Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States); Riesterer, Jessica Lori [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, Brandon Douglas [Idaho National Lab. (INL), Idaho Falls, ID (United States); Janney, Dawn Elizabeth [Idaho National Lab. (INL), Idaho Falls, ID (United States); Harp, Jason Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ploger, Scott Arden [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2012-12-01

    The electron microscopic examination of selected irradiated TRISO coated particles of the AGR-1 experiment of fuel compact 6-3-2 are presented in this report. Compact 6-3-2 refers to the compact in Capsule 6 at level 3 of Stack 2. The fuel used in capsule 6 compacts, are called the “baseline” fuel as it is fabricated with refined coating process conditions used to fabricate historic German fuel, because of its excellent irradiation performance with UO2 kernels. The AGR-1 fuel is however made of low-enriched uranium oxycarbide (UCO). Kernel diameters are approximately 350 µm with a U-235 enrichment of approximately 19.7%. Compact 6-3-2 has been irradiated to 11.3% FIMA compact average burn-up with a time average, volume average temperature of 1070.2°C and with a compact average fast fluence of 2.38E21 n/cm

  15. Measuring the critical current in superconducting samples made of NT-50 under pulse irradiation by high-energy particles

    International Nuclear Information System (INIS)

    Vasilev, P.G.; Vladimirova, N.M.; Volkov, V.I.; Goncharov, I.N.; Zajtsev, L.N.; Zel'dich, B.D.; Ivanov, V.I.; Kleshchenko, E.D.; Khvostov, V.B.

    1981-01-01

    The results of tests of superconducting samples of an uninsulated wire of the 0.5 mm diameter, containing 1045 superconducting filaments of the 10 μm diameter made of NT-50 superconductor in a copper matrix, are given. The upper part of the sample (''closed'') is placed between two glass-cloth-base laminate plates of the 50 mm length, and the lower part (''open'') of the 45 mm length is immerged into liquid helium. The sample is located perpendicular to the magnetic field of a superconducting solenoid and it is irradiated by charged particle beams at the energy of several GeV. The measurement results of permissible energy release in the sample depending on subcriticality (I/Isub(c) where I is an operating current through the sample, and Isub(c) is a critical current for lack of the beam) and the particle flux density, as well as of the maximum permissible fluence depending on subcriticality. In case of the ''closed'' sample irradiated by short pulses (approximately 1 ms) for I/Isub(c) [ru

  16. Study of energetic-particle-irradiation induced biological effect on Rhizopus oryzae through synchrotron-FTIR micro-spectroscopy

    Science.gov (United States)

    Liu, Jinghua; Qi, Zeming; Huang, Qing; Wei, Xiaoli; Ke, Zhigang; Fang, Yusheng; Tian, Yangchao; Yu, Zengliang

    2013-01-01

    Energetic particles exist ubiquitously and cause varied biological effects such as DNA strand breaks, lipid peroxidation, protein modification, cell apoptosis or death. An emerging biotechnology based on ion-beam technique has been developed to serve as an effective tool for mutation breeding of crops and microbes. In order to improve the effectiveness of ion-beam biotechnology for mutation breeding, it is indispensible to gain a better understanding of the mechanism of the interactions between the energetic ions and biological systems which is still elusive. A new trend is to conduct more comprehensive research which is based on micro-scaled observation of the changes of the cellular structures and compositions under the interactions. For this purpose, advanced synchrotron FTIR (s-FTIR) microscopy was employed to monitor the cellular changes of single fungal hyphae under irradiation of α-particles from 241Am. Intracellular contents of ROS, MDA, GSSG/GSH and activities of CAT and SOD were measured via biochemical assay. Ion-irradiation on Rhizopus oryzae causes localized vacuolation, autolysis of cell wall and membrane, lipid peroxidation, DNA damage and conformational changes of proteins, which have been clearly revealed by the s-FTIR microspectroscopy. The different changes of cell viability, SOD and CAT activities can be explained by the ROS-involved chemical reactions. Evidently, the elevated level of ROS in hyphal cells upon irradiation plays the key role in the caused biological effect. This study demonstrates that s-FTIR microspectroscopy is an effective tool to study the damage of fungal hyphae caused by ionizing radiation and it facilitates the exploit of the mechanism for the interactions between the energetic ions and biological systems.

  17. The use of gamma irradiation in preparation of polybutadiene rubber nanopowder; Its effect on particle size, morphology and crosslink structure of the powder

    Science.gov (United States)

    Rezaei Abadchi, Majid; Jalali-Arani, Azam

    2014-02-01

    The aim of this work was the preparation and characterization of polybutadiene rubber (BR) powder by irradiating of rubber lattices using 60Co radiation and spray-drying of them at the appropriate condition. The influences of absorbed dose on the volume swelling ratio, molecular weight between crosslinks, gel fraction, and glass transition temperature of obtained powder were studied. Morphology, size and size distribution of rubber particles were examined by using scanning electron microscopy (SEM) and laser particle size analyzer (LPSA) technique, respectively. Results obtained by LPSA revealed that radiation has no effect on particle size of rubber latex but after drying, adherence properties of rubber particle causes increase in particle size of rubber powder, as shown in SEM photograph. Fourier transform infrared spectroscopy of rubber powders confirmed that with increasing the irradiation dose, characteristic peak corresponds to the >Cdbnd C< double bands decreased. Also Charlesby-Pinner equation was used to evaluate radiation yield.

  18. PARTICLE, a Triplex-Forming Long ncRNA, Regulates Locus-Specific Methylation in Response to Low-Dose Irradiation

    Directory of Open Access Journals (Sweden)

    Valerie Bríd O’Leary

    2015-04-01

    Full Text Available Exposure to low-dose irradiation causes transiently elevated expression of the long ncRNA PARTICLE (gene PARTICLE, promoter of MAT2A-antisense radiation-induced circulating lncRNA. PARTICLE affords both a cytosolic scaffold for the tumor suppressor methionine adenosyltransferase (MAT2A and a nuclear genetic platform for transcriptional repression. In situ hybridization discloses that PARTICLE and MAT2A associate together following irradiation. Bromouridine tracing and presence in exosomes indicate intercellular transport, and this is supported by ex vivo data from radiotherapy-treated patients. Surface plasmon resonance indicates that PARTICLE forms a DNA-lncRNA triplex upstream of a MAT2A promoter CpG island. We show that PARTICLE represses MAT2A via methylation and demonstrate that the radiation-induced PARTICLE interacts with the transcription-repressive complex proteins G9a and SUZ12 (subunit of PRC2. The interplay of PARTICLE with MAT2A implicates this lncRNA in intercellular communication and as a recruitment platform for gene-silencing machineries through triplex formation in response to irradiation.

  19. The behaviour of transport from the fission products caesium and strontium in coated particles for high temperature reactors under irradiation conditions

    International Nuclear Information System (INIS)

    Zoller, P.

    1976-07-01

    At first survey is given about existing knowledge of the behaviour of caesium and strontium fission product transport in coated particles. In order to describe the complicated fission product transport mechanisms under irradiation conditions a suitable calculating model (SLIPPER) is taken over and modified to the special problems of an irradiation experiment. Fundamentally, the fission product transport is represented by the two contributions of diffusion and recoil, at which the diffusion is described by effective diffusion coefficients. In difference of that the possibility of a two-phase-diffusion is examined for the Cs diffusion in the fuel kernel. The model application on measuring results from irradiation experiments of KFA-Juelich and Mol-Belgien allowed the explanation from the characteristic of fission product transport in coated particles under irradiation conditions and produced effective diffusion coefficients for the fission products Cs and Sr. (orig.) [de

  20. Charged-particle acceleration through laser irradiation of thin foils at Prague Asterix Laser System

    International Nuclear Information System (INIS)

    Torrisi, Lorenzo; Cutroneo, Maria; Cavallaro, Salvatore; Musumeci, Paolo; Calcagno, Lucia; Wolowski, Jerzy; Rosinski, Marcin; Zaras-Szydlowska, Agnieszka; Ullschmied, Jiri; Krousky, Eduard; Pfeifer, Miroslav; Skala, Jiri; Velyhan, Andreiy

    2014-01-01

    Thin foils, 0.5–50 μm in thickness, have been irradiated in vacuum at Prague Asterix Laser System in Prague using 10 15–16  W cm −2 laser intensity, 1315 nm wavelength, 300 ps pulse duration and different focal positions. Produced plasmas from metals and polymers films have been monitored in the forward and backward directions. Ion and electron accelerations have been investigated by using Thomson parabola spectrometer, x-ray streak camera, ion collectors and SiC semiconductor detectors, the latter employed in time-of-flight configuration. Ion acceleration up to about 3 MeV per charge state was measured in the forward direction. Ion and electron emissions were detected at different angles as a function of the irradiation conditions. (paper)

  1. Postirradiation examination report of TRISO and BISO coated ThO2 particles irradiated in capsules HT-31 and HT-33

    International Nuclear Information System (INIS)

    Sedlak, B.J.

    1980-01-01

    Capsules HT-31 and HT-33 were uninstrumented capsule experiments irradiated in the target position of the High-Flux Isotope Reactor at Oak Ridge National Laboratory. The experiments were used to evaluate the irradiation performance of (1) fuel fabricated in a 240-mm-diameter coater for production scale-up, (2) TRISO ThO 2 and BISO ThO 2 particles, and (3) fuel with certain OPyC variables. A total of 16 BISO particle samples and 32 TRISO particle samples were irradiated to fast neutron fluences ranging from 4.0 to 11.7 x 10 25 n/m 2 (E > 29 fJ)/sub HTGR/ and heavy metal burnups between 3.5% and 13.2% FIMA at temperatures from 1150 0 to 1530 0 C

  2. CHARGE-2/C, Flux and Dose Behind Shield from Electron, Proton, Heavy Particle Irradiation

    International Nuclear Information System (INIS)

    Ucker, W.R.; Lilley, J.R.

    1994-01-01

    1 - Description of problem or function: The CHARGE code computes flux spectra, dose and other response rates behind a multilayered spherical or infinite planar shield exposed to isotopic fluxes of electrons, protons and heavy charged particles. The doses, or other responses, to electron, primary proton, heavy particle, electron Bremsstrahlung, secondary proton, and secondary neutron radiations are calculated as a function of penetration into the shield; the materials of each layer may be mixtures of elements contained in the accompanying data library, or supplied by the user. The calculation may optionally be halted before the entire shield is traversed by specifying a minimum total dose rate; the computation stops when the dose drops below this value. The ambient electron, proton and heavy particle spectra may be specified in tabular or functional form. These incident charged particle spectra are divided into energy bands or groups, the number or spacing of which are controlled by input data. The variation of the group boundary energies and group spectra as a function of shield penetration uniquely determines charged particle dose rates and secondary particle production rates. The charged particle shielding calculation is essentially the integration of the range- energy equation which expresses the variation of particle energy wit distance travelled. 2 - Method of solution: The 'straight-ahead' approximation is used throughout, that is the changes in particle direction of motion due to elastic scattering are ignored. This approximation is corrected, in the case of electrons, by applying transmission factors obtained from Monte Carlo calculations. Inelastic scattering between protons and the shielding material is assumed to produce two classes of secondaries 1) Cascade protons and neutrons, emitted in the same direction as the primaries 2) Evaporation neutrons, emitted isotropically. The transmission of secondary protons is analyzed in exactly the same way as the

  3. Particle-in-cell simulation of electron trajectories and irradiation uniformity in an annular cathode high current pulsed electron beam source

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Wei; Wang, Langping, E-mail: aplpwang@hit.edu.cn; Zhou, Guangxue; Wang, Xiaofeng

    2017-02-01

    Highlights: • The transmission process of electrons and irradiation uniformity was simulated. • Influence of the irradiation parameters on irradiation uniformity are discussed. • High irradiation uniformity can be obtained in a wide processing window. - Abstract: In order to study electron trajectories in an annular cathode high current pulsed electron beam (HCPEB) source based on carbon fiber bunches, the transmission process of electrons emitted from the annular cathode was simulated using a particle-in-cell model with Monte Carlo collisions (PIC-MCC). The simulation results show that the intense flow of the electrons emitted from the annular cathode are expanded during the transmission process, and the uniformity of the electron distribution is improved in the transportation process. The irradiation current decreases with the irradiation distance and the pressure, and increases with the negative voltage. In addition, when the irradiation distance and the cathode voltage are larger than 40 mm and −15 kV, respectively, a uniform irradiation current distribution along the circumference of the anode can be obtained. The simulation results show that good irradiation uniformity of circular components can be achieved by this annular cathode HCPEB source.

  4. Elaboration by ion implantation of cobalt nano-particles in silica layers and modifications of their properties by electron and swift heavy ion irradiations

    International Nuclear Information System (INIS)

    D'Orleans, C.

    2003-07-01

    This work aims to investigate the capability of ion irradiations to elaborate magnetic nano-particles in silica layers, and to modify their properties. Co + ions have been implanted at 160 keV at fluences of 2.10 16 , 5.10 16 and 10 17 at/cm 2 , and at temperatures of 77, 295 and 873 K. The dependence of the particle size on the implantation fluence, and more significantly on the implantation temperature has been shown. TEM (transmission electronic microscopy) observations have shown a mean diameter varying from 1 nm for implantations at 2.10 16 Co + /cm 2 at 77 K, to 9.7 nm at 10 17 Co + /cm 2 at 873 K. For high temperature implantations, two regions of particles appear. Simulations based on a kinetic 3-dimensional lattice Monte Carlo method reproduce quantitatively the features observed for implantations. Thermal treatments induce the ripening of the particles. Electron irradiations at 873 K induce an important increase in mean particle sizes. Swift heavy ion irradiations also induce the ripening of the particles for low fluences, and an elongation of the particles in the incident beam direction for high fluences, resulting in a magnetic anisotropy. Mechanisms invoked in thermal spike model could also explain this anisotropic growth. (author)

  5. Defect-induced ferromagnetism in semiconductors: A controllable approach by particle irradiation

    International Nuclear Information System (INIS)

    Zhou, Shengqiang

    2014-01-01

    Making semiconductors ferromagnetic has been a long dream. One approach is to dope semiconductors with transition metals (TM). TM ions act as local moments and they couple with free carriers to develop collective magnetism. However, there are no fundamental reasons against the possibility of local moment formation from localized sp states. Recently, ferromagnetism was observed in nonmagnetically doped, but defective semiconductors or insulators including ZnO and TiO 2 . This kind of observation challenges the conventional understanding of ferromagnetism. Often the defect-induced ferromagnetism has been observed in samples prepared under non-optimized condition, i.e. by accident or by mistake. Therefore, in this field theory goes much ahead of experimental investigation. To understand the mechanism of the defect-induced ferromagnetism, one needs a better controlled method to create defects in the crystalline materials. As a nonequilibrium and reproducible approach of inducing defects, ion irradiation provides such a possibility. Energetic ions displace atoms from their equilibrium lattice sites, thus creating mainly vacancies, interstitials or antisites. The amount and the distribution of defects can be controlled by the ion fluence and energy. By ion irradiation, we have generated defect-induced ferromagnetism in ZnO, TiO 2 and SiC. In this short review, we also summarize some results by other groups using energetic ions to introduce defects, and thereby magnetism in various materials. Ion irradiation combined with proper characterizations of defects could allow us to clarify the local magnetic moments and the coupling mechanism in defective semiconductors. Otherwise we may have to build a new paradigm to understand the defect-induced ferromagnetism

  6. Relative biological effectiveness in canine osteosarcoma cells irradiated with accelerated charged particles

    Science.gov (United States)

    Maeda, Junko; Cartwright, Ian M.; Haskins, Jeremy S.; Fujii, Yoshihiro; Fujisawa, Hiroshi; Hirakawa, Hirokazu; Uesaka, Mitsuru; Kitamura, Hisashi; Fujimori, Akira; Thamm, Douglas H.; Kato, Takamitsu A.

    2016-01-01

    Heavy ions, characterized by high linear energy transfer (LET) radiation, have advantages compared with low LET protons and photons in their biological effects. The application of heavy ions within veterinary clinics requires additional background information to determine heavy ion efficacy. In the present study, comparison of the cell-killing effects of photons, protons and heavy ions was investigated in canine osteosarcoma (OSA) cells in vitro. A total of four canine OSA cell lines with various radiosensitivities were irradiated with 137Cs gamma-rays, monoenergetic proton beams, 50 keV/µm carbon ion spread out Bragg peak beams and 200 keV/µm iron ion monoenergetic beams. Clonogenic survival was examined using colony-forming as says, and relative biological effectiveness (RBE) values were calculated relative to gamma-rays using the D10 value, which is determined as the dose (Gy) resulting in 10% survival. For proton irradiation, the RBE values for all four cell lines were 1.0–1.1. For all four cell lines, exposure to carbon ions yielded a decreased cell survival compared with gamma-rays, with the RBE values ranging from 1.56–2.10. Iron ions yielded the lowest cell survival among tested radiation types, with RBE values ranging from 3.51–3.69 observed in the three radioresistant cell lines. The radiosensitive cell line investigated demonstrated similar cell survival for carbon and iron ion irradiation. The results of the present study suggest that heavy ions are more effective for killing radioresistant canine OSA cells when compared with gamma-rays and protons. This markedly increased efficiency of cell killing is an attractive reason for utilizing heavy ions for radioresistant canine OSA. PMID:27446477

  7. Real-time optical tracking for motion compensated irradiation with scanned particle beams at CNAO

    Energy Technology Data Exchange (ETDEWEB)

    Fattori, G., E-mail: giovanni.fattori@psi.ch [Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Seregni, M. [Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Pella, A. [Centro Nazionale di Adroterapia Oncologica (CNAO), Strada Campeggi 53, 27100 Pavia (Italy); Riboldi, M. [Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Capasso, L. [Istituto Nazionale di Fisica Nucleare, Section of Torino, Torino 10125 (Italy); Donetti, M. [Centro Nazionale di Adroterapia Oncologica (CNAO), Strada Campeggi 53, 27100 Pavia (Italy); Istituto Nazionale di Fisica Nucleare, Section of Torino, Torino 10125 (Italy); Ciocca, M. [Centro Nazionale di Adroterapia Oncologica (CNAO), Strada Campeggi 53, 27100 Pavia (Italy); Giordanengo, S. [Istituto Nazionale di Fisica Nucleare, Section of Torino, Torino 10125 (Italy); Pullia, M. [Centro Nazionale di Adroterapia Oncologica (CNAO), Strada Campeggi 53, 27100 Pavia (Italy); Marchetto, F. [Istituto Nazionale di Fisica Nucleare, Section of Torino, Torino 10125 (Italy); Baroni, G. [Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Centro Nazionale di Adroterapia Oncologica (CNAO), Strada Campeggi 53, 27100 Pavia (Italy)

    2016-08-11

    Purpose: We describe the interface developed at the National Center for Oncological Hadrontherapy in Pavia to provide the dose delivery systems with real time respiratory motion information captured with an optical tracking system. An experimental study is presented to assess the technical feasibility of the implemented organ motion compensation framework, by analyzing the film response when irradiated with proton beams. Methods: The motion monitoring solution is based on a commercial hardware for motion capture running in-house developed software for respiratory signal processing. As part of the integration, the latency of data transmission to the dose delivery system was experimentally quantified and accounted for by signal time prediction. A respiratory breathing phantom is presented and used to test tumor tracking based either on the optical measurement of the target position or internal-external correlation models and beam gating, as driven by external surrogates. Beam tracking was tested considering the full target motion excursion (25×18 mm), whereas it is limited to 6×2 mm in the gating window. The different motion mitigation strategies were evaluated by comparing the experimental film responses with respect to static irradiation conditions. Dose inhomogeneity (IC) and conformity (CI) are provided as main indexes for dose quality assessment considering the irradiation in static condition as reference. Results: We measured 20.6 ms overall latency for motion signal processing. Dose measurements showed that beam tracking largely preserved dose homogeneity and conformity, showing maximal IC and CI variations limited to +0.10 and −0.01 with respect to the static reference. Gating resulted in slightly larger discrepancies (ΔIC=+0.20, ΔCI=−0.13) due to uncompensated residual motion in the gating window. Conclusions: The preliminary beam tracking and gating results verified the functionality of the prototypal solution for organ motion compensation based on

  8. Real-time optical tracking for motion compensated irradiation with scanned particle beams at CNAO

    International Nuclear Information System (INIS)

    Fattori, G.; Seregni, M.; Pella, A.; Riboldi, M.; Capasso, L.; Donetti, M.; Ciocca, M.; Giordanengo, S.; Pullia, M.; Marchetto, F.; Baroni, G.

    2016-01-01

    Purpose: We describe the interface developed at the National Center for Oncological Hadrontherapy in Pavia to provide the dose delivery systems with real time respiratory motion information captured with an optical tracking system. An experimental study is presented to assess the technical feasibility of the implemented organ motion compensation framework, by analyzing the film response when irradiated with proton beams. Methods: The motion monitoring solution is based on a commercial hardware for motion capture running in-house developed software for respiratory signal processing. As part of the integration, the latency of data transmission to the dose delivery system was experimentally quantified and accounted for by signal time prediction. A respiratory breathing phantom is presented and used to test tumor tracking based either on the optical measurement of the target position or internal-external correlation models and beam gating, as driven by external surrogates. Beam tracking was tested considering the full target motion excursion (25×18 mm), whereas it is limited to 6×2 mm in the gating window. The different motion mitigation strategies were evaluated by comparing the experimental film responses with respect to static irradiation conditions. Dose inhomogeneity (IC) and conformity (CI) are provided as main indexes for dose quality assessment considering the irradiation in static condition as reference. Results: We measured 20.6 ms overall latency for motion signal processing. Dose measurements showed that beam tracking largely preserved dose homogeneity and conformity, showing maximal IC and CI variations limited to +0.10 and −0.01 with respect to the static reference. Gating resulted in slightly larger discrepancies (ΔIC=+0.20, ΔCI=−0.13) due to uncompensated residual motion in the gating window. Conclusions: The preliminary beam tracking and gating results verified the functionality of the prototypal solution for organ motion compensation based on

  9. Interaction between UO2 kernel and pyrocarbon coating in irradiated and unirradiated HTR fuel particles

    International Nuclear Information System (INIS)

    Drago, A.; Klersy, R.; Simoni, O.; Schrader, K.H.

    1975-08-01

    Experimental observations on unidirectional UO 2 kernel migration in TRISO type coated particle fuels are reported. An analysis of the experimental results on the basis of data and models from the literature is reported. The stoichiometric composition of the kernel is considered the main parameter that, associated with a temperature gradient, controls the unidirectional kernel migration

  10. Transcriptional Response of Human Cells to Microbeam Irradiation with 2.1 MeV Alpha Particles

    Science.gov (United States)

    Hellweg, C. E.; Bogner, S.; Spitta, L.; Arenz, A.; Baumstark-Khan, C.; Greif, K. D.; Giesen, U.

    Within the next decades an increasing number of human beings in space will be simultaneously exposed to different stimuli especially microgravity and radiation To assess the risks for humans during long-duration space missions the complex interplay of these parameters at the cellular level must be understood Cellular stress protection responses lead to increased transcription of several genes via modulation of transcription factors Activation of the Nuclear Factor kappa B NF- kappa B pathway as a possible anti-apoptotic route represents such an important cellular stress response A screening assay for detection of NF- kappa B-dependent gene activation using the destabilized variant of Enhanced Green Fluorescent Protein d2EGFP as reporter protein had been developed It consists of Human Embryonic Kidney HEK 293 Cells stably transfected with a receptor-reporter-construct carrying d2EGFP under the control of a NF- kappa B response element Clones positive for Tumor Necrosis Factor alpha TNF- alpha inducible d2EGFP expression were selected as cellular reporters Irradiation was performed either with X-rays 150 kV 19 mA at DLR Cologne or with 2 1 MeV alpha particles LET sim 160 keV mu m at PTB Braunschweig After irradiation the following biological endpoints were determined i cell survival via the colony forming ability test ii time-dependent activation of NF- kappa B dependent d2EGFP gene expression using flow cytometry iii quantitative RT-PCR

  11. The shape of dose-effect curves for diploid yeast cells irradiated with ionizing particles

    International Nuclear Information System (INIS)

    Pohlit, W.

    1975-01-01

    In a cybernetic model for the radiation reactions in eukaryotic cells, after irradiation they are assumed to be in one of three states: (a) viable cells; (b) with repairable damage; and (c) with irreparable damage. Two biological counter reactions with certain time constants can be observed: (i) recovery from sublethal damage; and (ii) repair of potential lethal damage. The shape of the dose-effect curve is influenced in a characteristic way by the different occupation of these states of the cells and by the time constants of the biological counter reactions. The biochemical analysis of the biological counter reactions, recovery and repair, has shown that both are linked together by the energy pool in the cell. In this way changes in the slope of the dose-effect curve due to different metabolic states of the cells can be understood quantitatively. Also the complicated dependence of survival cells on the absorbed dose rate over a wide range can be explained quantitatively. (author)

  12. Fabrication of substrates with curvature for cell cultivation by alpha-particle irradiation and chemical etching of PADC films

    International Nuclear Information System (INIS)

    Ng, C.K.M.; Tjhin, V.T.; Lin, A.C.C.; Cheng, J.P.; Cheng, S.H.; Yu, K.N.

    2012-01-01

    In the present paper, we developed a microfabrication technology to generate cell-culture substrates with identical chemistry and well-defined curvature. Micrometer-sized pits with curved surfaces were created on a two-dimensional surface of a polymer known as polyallyldiglycol carbonate (PADC). A PADC film was first irradiated by alpha particles and then chemically etched under specific conditions to generate pits with well-defined curvature at the incident positions of the alpha particles. The surface with these pits was employed as a model system for studying the effects of substrate curvature on cell behavior. As an application, the present work studied mechanosensing of substrate curvature by epithelial cells (HeLa cells) through regulation of microtubule (MT) dynamics. We used end-binding protein 3–green fluorescent protein (EB3–GFP) as a marker of MT growth to show that epithelial cells having migrated into the pits with curved surfaces had significantly smaller MT growth speeds than those having stayed on flat surfaces without the pits.

  13. Transmission electron microscopy investigation of neutron irradiated Si and ZrN coated UMo particles prepared using FIB

    Science.gov (United States)

    Van Renterghem, W.; Miller, B. D.; Leenaers, A.; Van den Berghe, S.; Gan, J.; Madden, J. W.; Keiser, D. D.

    2018-01-01

    Two fuel plates, containing Si and ZrN coated U-Mo fuel particles dispersed in an Al matrix, were irradiated in the BR2 reactor of SCK•CEN to a burn-up of ∼70% 235U. Five samples were prepared by INL using focused ion beam milling and transported to SCK•CEN for transmission electron microscopy (TEM) investigation. Two samples were taken from the Si coated U-Mo fuel particles at a burn-up of ∼42% and ∼66% 235U and three samples from the ZrN coated U-Mo at a burn-up of ∼42%, ∼52% and ∼66% 235U. The evolution of the coating, fuel structure, fission products and the formation of interaction layers are discussed. Both coatings appear to be an effective barrier against fuel matrix interaction and only on the samples having received the highest burn-up and power, the formation of an interaction between Al and U(Mo) can be observed on those locations where breaches in the coatings were formed during plate fabrication.

  14. Nitric oxide mediated DNA double strand breaks induced in proliferating bystander cells after {alpha}-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Han Wei [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Chen Shaopeng [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Yu, K.N., E-mail: peter.yu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Wu Lijun [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2010-02-03

    Low-dose {alpha}-particle exposures comprise 55% of the environmental dose to the human population and have been shown to induce bystander responses. Previous studies showed that bystander effect could induce stimulated cell growth or genotoxicity, such as excessive DNA double strand breaks (DSBs), micronuclei (MN), mutation and decreased cell viability, in the bystander cell population. In the present study, the stimulated cell growth, detected with flow cytometry (FCM), and the increased MN and DSB, detected with p53 binding protein 1 (53BP1) immunofluorescence, were observed simultaneously in the bystander cell population, which were co-cultured with cells irradiated by low-dose {alpha}-particles (1-10 cGy) in a mixed system. Further studies indicated that nitric oxide (NO) and transforming growth factor {beta}1 (TGF-{beta}1) played very important roles in mediating cell proliferation and inducing MN and DSB in the bystander population through treatments with NO scavenger and TGF-{beta}1 antibody. Low-concentrations of NO, generated by spermidine, were proved to induce cell proliferation, DSB and MN simultaneously. The proliferation or shortened cell cycle in bystander cells gave them insufficient time to repair DSBs. The increased cell division might increase the probability of carcinogenesis in bystander cells since cell proliferation increased the probability of mutation from the mis-repaired or un-repaired DSBs.

  15. Nitric oxide mediated DNA double strand breaks induced in proliferating bystander cells after α-particle irradiation

    International Nuclear Information System (INIS)

    Han Wei; Chen Shaopeng; Yu, K.N.; Wu Lijun

    2010-01-01

    Low-dose α-particle exposures comprise 55% of the environmental dose to the human population and have been shown to induce bystander responses. Previous studies showed that bystander effect could induce stimulated cell growth or genotoxicity, such as excessive DNA double strand breaks (DSBs), micronuclei (MN), mutation and decreased cell viability, in the bystander cell population. In the present study, the stimulated cell growth, detected with flow cytometry (FCM), and the increased MN and DSB, detected with p53 binding protein 1 (53BP1) immunofluorescence, were observed simultaneously in the bystander cell population, which were co-cultured with cells irradiated by low-dose α-particles (1-10 cGy) in a mixed system. Further studies indicated that nitric oxide (NO) and transforming growth factor β1 (TGF-β1) played very important roles in mediating cell proliferation and inducing MN and DSB in the bystander population through treatments with NO scavenger and TGF-β1 antibody. Low-concentrations of NO, generated by spermidine, were proved to induce cell proliferation, DSB and MN simultaneously. The proliferation or shortened cell cycle in bystander cells gave them insufficient time to repair DSBs. The increased cell division might increase the probability of carcinogenesis in bystander cells since cell proliferation increased the probability of mutation from the mis-repaired or un-repaired DSBs.

  16. Irradiation behavior of the interaction product of U-Mo fuel particle dispersion in an Al matrix

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yeon Soo, E-mail: yskim@anl.gov [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Hofman, G.L. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer We in-pile tested U-Mo dispersion in Al matrix. Black-Right-Pointing-Pointer We observed interaction layer growth between U-Mo and Al and pore formation there. Black-Right-Pointing-Pointer Pores degrades thermal conductivity and structural integrity of the fueled zone. Black-Right-Pointing-Pointer The amorphous behavior of interaction layers is thought to be the main reason for unstable large pore growth. Black-Right-Pointing-Pointer A mechanism for pore formation and possible remedy to prevent it are proposed. - Abstract: Irradiation performance of U-Mo fuel particles dispersed in Al matrix is stable in terms of fuel swelling and is suitable for the conversion of research and test reactors from highly enriched uranium (HEU) to low enriched uranium (LEU). However, tests of the fuel at high temperatures and high burnups revealed obstacles caused by the interaction layers forming between the fuel particle and matrix. In some cases, fission gas filled pores grow and interconnect in the interdiffusion layer resulting in fuel plate failure. Postirradiation observations are made to examine the behavior of the interdiffusion layers. The interdiffusion layers show a fluid-like behavior characteristic of amorphous materials. In the amorphous interdiffusion layers, fission gas diffusivity is high and the material viscosity is low so that the fission gas pores readily form and grow. Based on the observations, a pore formation mechanism is proposed and potential remedies to suppress the pore growth are also introduced.

  17. Special topics. Advances of radiation biology in heavy particle therapy- review. Effects of photon and heavy particle irradiation on metastasis and angiogenesis

    International Nuclear Information System (INIS)

    Ogata, Toshiyuki; Teshima, Teruki; Takahashi, Yutaka; Matsuura, Nariaki; Furusawa, Yoshiya

    2009-01-01

    Described are effects of photon and heavy particle (HP) irradiation on the process of tumor metastasis (MT) and accompanying angiogenesis (AG) at molecular, cellular and animal levels. Recent animal studies of molecular mechanistic elucidation of increased MT by photon have revealed the participation of activated proteins like matrix metalloproteinase (MMP) and integrins, of increased secretion of growth factors, of up-regulation of receptors like for that of urokinase-type plasminogen activator under hypoxia, and so on. Authors have studied the effect of HP on cellular MMP and integrins and on MT in tumor-bearing mice, and suggested a suppression of MT by HP. Vascular endothelial cells, playing a major role in AG, are resistant to low dose (e.g., 3 Gy) radiation and sensitive to higher dose (9-20 Gy), which has resulted in various complicating findings on MT. There are also many findings on MT and/or AG relations with various treatments like surgical or photon treatment of the primary tumor and AG suppressive substances, where further examinations are necessary for practical use of photon/drug therapy to prevent MT through AG participation. Authors have implicated in vitro that HP, even at low dose (0.1 Gy, sublethal), can suppress MT through AG mechanism. Thus prevention of MT by HP is thought promising in future when their mutual interaction is elucidated more clearly. (K.T.)

  18. Creep tests of AISI 316 stainless steel irradiated by alpha particles of 28 MeV

    International Nuclear Information System (INIS)

    Segura, E.; Lucki, G.

    1986-01-01

    He-embrittlement effect in AISI 316 SS type throught creep tests performed with annealed and cold worked thin specimens is analized. Measurements were carried out at 700 and 750 0 C, stress of 100 MPa in vacuum better than 10 -5 torr. The He-implantations were made with the cyclotron CV-28 IPEN-CNEN/SP. Using an alpha-particle beam of 28 MeV, with concentration of 26 appm. From the valves of rupture deformation, epsilon sub(R), and rupture time, t sub(R), it was verified that he had a great effect on the operational life and ductility of this material. (Author) [pt

  19. Secondary neutron production from thick Pb target by light particle irradiation

    CERN Document Server

    Adloff, J C; Debeauvais, M; Fernández, F; Krivopustov, M; Kulakov, B A; Sosnin, A; Zamani, M

    1999-01-01

    Neutron multiplicities from spallation neutron sources were measured by Solid State Nuclear Track Detectors. Light particles as protons, deuterons and alphas in the GeV range were used on Pb targets. For neutron thermalization the targets were covered by 6 cm paraffin moderator. Neutron multiplicity distributions were studied inside and on the moderator surface. Comparison of SSNTDs results were made for thermal-epithermal neutrons with sup 1 sup 3 sup 9 La activation method as well as with Dubna DCM/CEM code. Discussion including previous sup 1 sup 2 C results are given.

  20. Thermoluminescent characterization of thin films of aluminium oxide irradiated with beta particles

    International Nuclear Information System (INIS)

    Villagran, E.; Escobar A, L.; Camps, E.; Gonzalez, P.R.

    2002-01-01

    By means of the laser ablation technique has been settled thin films of aluminium oxide on kapton substrates. These films present thermoluminescent response (Tl) when being exposed to beta radiation of a Sr 90 - Y 90 source (E max = 2.28 MeV). The brilliance curves show two peaks, one of them in 112 C degrees and the other one in 180 C degrees. The peak of low temperature is faded in some hours, whereas the high temperature one is more stable, showing a fading in the 15% order after three days of the irradiation. The Tl kinetic parameters were determined using the computerized deconvolution of the brilliance curve (CGDC). The results show that the high temperature peak is composed by four peaks which obey a second order kinetics with their maximum located at 165.7, 188.1, 215.3, and 246.5 C degrees. The depth of the traps (E) has values in the interval between 1.4 and 2.0 eV. The study of the dose response relation, show that the material presents a linear behavior in a dose interval from 150 mGy to 50 Gy. The obtained thin films of aluminium oxide could be a useful tool due to their potential applications in clinical dosimetry, in the determination of distributions of doses produced by penetrating weakly radiation, as well as in interfaces dosimetry. (Author)

  1. Electrically active defects in p-type silicon after alpha-particle irradiation

    Science.gov (United States)

    Danga, Helga T.; Auret, F. Danie; Tunhuma, Shandirai M.; Omotoso, Ezekiel; Igumbor, Emmanuel; Meyer, Walter E.

    2018-04-01

    In this work, we investigated the defects introduced when boron (B) doped silicon (Si) was irradiated by making use of a 5.4 MeV americium (Am) 241 foil radioactive source with a fluence rate of 7×106 cm-2 s-1 at room temperature. Deep level transient spectroscopy (DLTS) and Laplace-DLTS measurements were used to investigate the electronic properties of the introduced defects. After exposure at a fluence of 5.1×1010 cm-2, the energy levels of the hole traps measured were: H(0.10), H(0.16), H(0.33) and H(0.52) The defect level H(0.10) was tri-vacancy related. H(0.33) was identified as the interstitial carbon (Ci) related defect which was a result of radiation induced damage. H(0.52) was a B-related defect. Explicit deductions about the origin of H(0.16) have not yet been achieved.

  2. CEMS and XRD studies on changing shape of iron nano-particles by irradiation of Au ions of Fe-implanted Al2O3 granular layer

    International Nuclear Information System (INIS)

    Kato, T.; Wakabayashi, H.; Hashimoto, M.; Toriyama, T.; Taniguchi, S.; Hayashi, N.; Sakamoto, I.

    2007-01-01

    In order to observe an inverse Ostwald ripening of Fe nano-particles in Fe-implanted Al 2 O 3 granular layers, 3 MeV Au ions were irradiated to Fe nano-particles in these layers with doses of 0.5x and 1.5x10 16 ions/cm 2 . It was found by Conversion Electron Mossbauer Spectroscopy (CEMS) that the inverse Ostwald ripening occurred by fractions of percentages and the magnetic anisotropy of Fe nano-particles was induced to the direction of Au ion beam, i.e. perpendicular to the granular plane. The average crystallite diameters of Fe nano-particles for Au ions unirradiated and irradiated samples were measured using Scherrer's formula from FWHM of Fe (110) X-ray Diffraction (XRD) patterns obtained by 2θ and 2θ/θ methods. It was confirmed that the average crystallite diameters of Fe nano-particles in Fe-implanted Al 2 O 3 granular layers were extended by Au ions irradiation. (author)

  3. Role of pigmentation in protecting bacterial cells against irradiation generated by accelerated charged particles

    International Nuclear Information System (INIS)

    Tiwary, Bhupendra Nath; Das, Reena

    2013-01-01

    Beams of high-energy particles are useful for both fundamental and applied research in the sciences, and also in many technical and industrial fields unrelated to fundamental research. It has been estimated that there are approximately 26,000 accelerators world. Of these, only about 1% are research machines with energies above 1 GeV, while about 44% are for radiotherapy, 41% for ion implantation, 9% for industrial processing and research, and 4% for biomedical and other low-energy research. One aspect of these radiations can be studied for examining their effect in altering the viability of bacterial cells. The radiations generated by the simple technology of a single static high voltage to accelerate charged particles are known to produce reactive oxygen intermediates such as hydrogen peroxide or superoxide anions and target several cellular components of bacterial cells including the DNA. As a result of this interaction with the DNA the phosphodiester backbone of the DNA may break leading to single or double strand fission. Endogenous pigments, such as carotenoids and melanins, might provide a selective advantage to these microorganisms by photoprotection or shielding from UV radiation, including the UV-C and full UV-B range. The pigment, as an antioxidant scavenges reactive oxygen species generated by UV-A radiation and protect various microorganisms against oxidative damage caused by UV or ionizing radiation by scavenging free radicals. Environmental UV radiation is polychromatic and comprises the full spectrum of UV-A and UV-B radiation at wavelengths of λ > 290 nm. Accelerators, solar simulators and natural insulation can also prove to be a better alternate for understanding the responses of bacterial cells to the terrestrial UV radiation climate. (author)

  4. Radiation Quality Effects on Transcriptome Profiles in 3-D Cultures After Charged Particle Irradiation

    Science.gov (United States)

    Patel, Zarana S.; Kidane, Yared H.; Huff, Janice L.

    2014-01-01

    In this work, we evaluated the differential effects of low- and high-LET radiation on 3-D organotypic cultures in order to investigate radiation quality impacts on gene expression and cellular responses. Current risk models for assessment of space radiation-induced cancer have large uncertainties because the models for adverse health effects following radiation exposure are founded on epidemiological analyses of human populations exposed to low-LET radiation. Reducing these uncertainties requires new knowledge on the fundamental differences in biological responses (the so-called radiation quality effects) triggered by heavy ion particle radiation versus low-LET radiation associated with Earth-based exposures. In order to better quantify these radiation quality effects in biological systems, we are utilizing novel 3-D organotypic human tissue models for space radiation research. These models hold promise for risk assessment as they provide a format for study of human cells within a realistic tissue framework, thereby bridging the gap between 2-D monolayer culture and animal models for risk extrapolation to humans. To identify biological pathway signatures unique to heavy ion particle exposure, functional gene set enrichment analysis (GSEA) was used with whole transcriptome profiling. GSEA has been used extensively as a method to garner biological information in a variety of model systems but has not been commonly used to analyze radiation effects. It is a powerful approach for assessing the functional significance of radiation quality-dependent changes from datasets where the changes are subtle but broad, and where single gene based analysis using rankings of fold-change may not reveal important biological information.

  5. Physico-mechanical Properties of Electron Beam Irradiated Particle boards Based on Wood flour/ Polyethylene/Cement Kiln Dust Impregnated with Unsaturated Polyester

    International Nuclear Information System (INIS)

    Abdel-Rahman, H.A.; Khattab, M.M.; Ismail, M.R.

    2010-01-01

    Particle boards were fabricated by mixing wood flour (WF), low density polyethylene (LDPE) and cement kiln dust (CKD) under hot pressure; and then impregnated in unsaturated polyester resin. These impregnated particle boards were subjected to various doses of electron beam irradiation up to 50 kGy. The physico-mechanical properties were characterized in terms of flexural strength, impact strength, water absorption, thickness swelling, and the thermal stability. The results showed that the partial replacement of wood flour with cement kiln dust up to 20% by weight improved the values of flexural strength, and impact strength. However, the water absorption percentage and thickness swelling values decreased with increasing the CKD ratio up to 40%. Furthermore, the treatment with electron beam irradiation doses improved the physico-mechanical properties of the impregnated particle boards up to 50 kGy. The improved results were confirmed by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA)

  6. Age/Radiation Parallels in the Effects of 56Fe Particle Irradiation and Protection by Berry Diets

    Science.gov (United States)

    Joseph, James; Bielinski, Donna; Carrihill-Knoll, Kirsty; Rabin, Bernard; Shukitt-Hale, Barbara

    Exposing young rats to particles of high-energy and charge (HZE particles) enhances indices of oxidative stress and inflammation and disrupts the functioning of the dopaminergic system and behaviors mediated by this system in a manner similar to that seen in aged animals Previous research has shown that diets supplemented with 2% blueberry or strawberry extracts have the ability to retard and even reverse age-related deficits in behavior and signal transduction in rats, perhaps due to their antioxidant and anti-inflammatory properties. A subsequent study has shown that whole-body irradiation with 1.5 Gy of 1 GeV/n high-energy 56 Fe particles impaired performance in the Morris water maze and measures of dopamine release one month following radiation; these deficits were protected by the antioxidant diets. The strawberry diet offered better protection against spatial deficits in the maze because strawberry-fed animals were better able to retain place information, while the blueberry-supplemented animals showed enhanced learning that was dependent on striatal functioning. Additional experiments in cell models to examine possible mechanisms involved in these beneficial effects have shown that, in addition to the well known free radical scavenging effects of berries, it appears that berry fruit can directly reduce stress signaling and enhance protective signals, suggesting the involvement of multiple mechanisms in the beneficial effects observed. Enhancements of "protective" signals (e.g., extracellular signal regulated kinase, ERK) include those that are involved in neuronal communication, neurogenesis, and learning and memory. Reductions in stress signaling include inhibiting nuclear factor kappa B (NF-κB) and cytokines, among others, induced by oxidative and inflammatory stressors. We have found these changes in both BV2 mouse microglial and hippocampal cells. We believe that the possible addition of colorful fruits such as berry fruits to the diet can possibly

  7. Production and Magnetic Field Confinement of Laser-Irradiated Solid Particle Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Haught, A. F.; Polk, D. H.; Fader, W. J. [United Aircraft Research Laboratories East Hartford, CT (United States)

    1969-01-15

    The focused high-intensity beam from a Q-spoiled laser has been used to form a high-temperature, high-density plasma from a single 10-20 micron radius solid particle of lithium hydride which is electrically suspended in a vacuum environment free of all material supports. Time-resolved charge collection measurements of the freely expanding plasma have shown that a high degree of ionization of the 10{sup 15} atoms in the lithium hydride particle can be achieved and that the plasma produced is essentially spherically symmetric in density over the full 4 {pi} solid angle. Time-of-flight studies of the plasma expansion have shown that average electron and ion energies exceeding 200 electron volts are obtained and that the plasma expansion rate, like the plasma density, is spherically symmetric. No charge separation or separation of the lithium and hydrogen ions is observed in the expanding plasma. Numerical calculations of the plasma formation and expansion have been made using a one-dimensional spherical hydrodynamic model and, on the basis of the results obtained, an integrated similarity model has been developed for calculations of the plasma time history and energy over the range of conditions employed in the experiments. These calculations, which include the effects of laser pulse time history, fraction of the incident beam occupied by the expanding plasma, radial density and velocity gradients within the plasma, and spatial distribution of the incident laser energy, give results for the plasma radial density distribution, velocity profile, and plasma energy in good agreement with those determined experimentally over the full range of the present measurements. Measurements have been carried out to examine the interaction of these laser -produced plasmas with mirror, cusp, and minimum-B magnetic fields. Experiments with mirror and minimum-B magnetic fields up to 8 kC show that plasmas with densities of 10{sup 12} -10{sup 13} cm{sup -3} are confined for times of 5

  8. Probabilistic methods for the simulation of fuel particles behavior under irradiation

    International Nuclear Information System (INIS)

    Cannamela, C.

    2007-09-01

    This work is devoted to the evaluation of mathematical expectations in the context of structural reliability. We seek a failure probability estimate (that we assume low), taking into account the uncertainty of influential parameters of the System. Our goal is to reach a good compromise between the accuracy of the estimate and the associated computational cost. This approach is used to estimate the failure probability of fuel particles from a HTR-type nuclear reactor. This estimate is obtain by means of costly numerical simulations. We consider different probabilistic methods to tackle the problem. First, we consider a variance reducing Monte Carlo method: importance sampling. For the parametric case, we propose adaptive algorithms in order to build a series of probability densities that will eventually converge to optimal importance density. We then present several estimates of the mathematical expectation based on this series of densities. Next, we consider a multi-level method using Monte Carlo Markov Chain algorithm. Finally, we turn our attention to the related problem of quantile estimation (non extreme) of physical output from a large-scale numerical code. We propose a controlled stratification method. The random input parameters are sampled in specific regions obtained from surrogate of the response. The estimation of the quantile is then computed from this sample. (author)

  9. Clustering of DSB in DNA by X-Ray and a-particle irradiation in MCF-7 cells studied with anti γ-H2AX

    International Nuclear Information System (INIS)

    Tapia, O.; Soto, J.; Castro, F.A.; Berciano, Ma T; Lafarga, M.; Cos, S.; Sanchez-Barcelo, E.

    2007-01-01

    Among the effects produced by the ionizing radiations in cellular DNA, double strand breaks (DSB) are considered particularly important. These ruptures and their grouping in certain points, clustering, are acknowledged as the cause for mutagenic effects and cellular death. In this work we present the methodology and the results of the application of the DSB - DNA marking technique by using anti γ-H2AX, taking human cancerous cells MCF-7 as model and X-rays and a particles as irradiation agents. The obtained results are showed in a qualitative way like a set of figures. Are shows the effects of a dose of 2 Gy X-rays in the DSB - DNA after 30 minutes of the irradiation that responds to a certain pattern in which a spatially homogenous irradiation interacts with the DNA. As in previous case, the effects of X-rays in the DSB - DNA shows a different pattern affecting the cells that are in mitosis. Also, the effects of a dose of 2 Gy X-rays obtained after 24 hours of irradiation shows a number of DSB smaller, which is indicative of the repairing process. The results of the irradiation with a dose of 0.1 Gy originated from a particles cause a smaller number of DSB. Nevertheless, the existence of a bigger clustering with the appearance of clearly more intense points is appraised. Also, the effect of the irradiation is showed as an aligned trace of clusters that is possible to attribute to the passing of a a particle through the cellular nucleus. (Author)

  10. Oxide particle size distribution from shearing irradiated and unirradiated LWR fuels in Zircaloy and stainless steel cladding: significance for risk assessment

    International Nuclear Information System (INIS)

    Davis, W. Jr.; West, G.A.; Stacy, R.G.

    1979-01-01

    Sieve fractionation was performed with oxide particles dislodged during shearing of unirradiated or irradiated fuel bundles or single rods of UO 2 or 96 to 97% ThO 2 --3 to 4% UO 2 . Analyses of these data by nonlinear least-squares techniques demonstrated that the particle size distribution is lognormal. Variables involved in the numerical analyses include lognormal median size, lognormal standard deviation, and shear cut length. Sieve-fractionation data are presented for unirradiated bundles of stainless-steel-clad or Zircaloy-2-clad UO 2 or ThO 2 --UO 2 sheared into lengths from 0.5 to 2.0 in. Data are also presented for irradiated single rods (sheared into lengths of 0.25 to 2.0 in.) of Zircaloy-2-clad UO 2 from BWRs and of Zircaloy-4-clad UO 2 from PWRs. Median particle sizes of UO 2 from shearing irradiated stainless-steel-clad fuel ranged from 103 to 182 μm; particle sizes of ThO 2 --UO 2 , under these same conditions, ranged from 137 to 202 μm. Similarly, median particle sizes of UO 2 from shearing unirradiated Zircaloy-2-clad fuel ranged from 230 to 957 μm. Irradiation levels of fuels from reactors ranged from 9,000 to 28,000 MWd/MTU. In general, particle sizes from shearing these irradiated fuels are larger than those from the unirradiated fuels. In addition, variations in particle size parameters pertaining to samples of a single vendor varied as much as those between different vendors. The fraction of fuel dislodged from the cladding is nearly proportional to the reciprocal of the shear cut length, until the cut length attains some minimum value below which all fuel is dislodged. Particles of fuel are generally elongated with a long-to-short axis ratio usually less than 3. Using parameters of the lognormal distribution deduced from experimental data, realistic estimates can be made of fractions of dislodged fuel having dimensions less than specified values

  11. Oxide particle size distribution from shearing irradiated and unirradiated LWR fuels in Zircaloy and stainless steel cladding: significance for risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    Davis, W. Jr.; West, G.A.; Stacy, R.G.

    1979-03-22

    Sieve fractionation was performed with oxide particles dislodged during shearing of unirradiated or irradiated fuel bundles or single rods of UO/sub 2/ or 96 to 97% ThO/sub 2/--3 to 4% UO/sub 2/. Analyses of these data by nonlinear least-squares techniques demonstrated that the particle size distribution is lognormal. Variables involved in the numerical analyses include lognormal median size, lognormal standard deviation, and shear cut length. Sieve-fractionation data are presented for unirradiated bundles of stainless-steel-clad or Zircaloy-2-clad UO/sub 2/ or ThO/sub 2/--UO/sub 2/ sheared into lengths from 0.5 to 2.0 in. Data are also presented for irradiated single rods (sheared into lengths of 0.25 to 2.0 in.) of Zircaloy-2-clad UO/sub 2/ from BWRs and of Zircaloy-4-clad UO/sub 2/ from PWRs. Median particle sizes of UO/sub 2/ from shearing irradiated stainless-steel-clad fuel ranged from 103 to 182 ..mu..m; particle sizes of ThO/sub 2/--UO/sub 2/, under these same conditions, ranged from 137 to 202 ..mu..m. Similarly, median particle sizes of UO/sub 2/ from shearing unirradiated Zircaloy-2-clad fuel ranged from 230 to 957 ..mu..m. Irradiation levels of fuels from reactors ranged from 9,000 to 28,000 MWd/MTU. In general, particle sizes from shearing these irradiated fuels are larger than those from the unirradiated fuels; however, unirradiated fuel from vendors was not available for performing comparative shearing experiments. In addition, variations in particle size parameters pertaining to samples of a single vendor varied as much as those between different vendors. The fraction of fuel dislodged from the cladding is nearly proportional to the reciprocal of the shear cut length, until the cut length attains some minimum value below which all fuel is dislodged. Particles of fuel are generally elongated with a long-to-short axis ratio usually less than 3. Using parameters of the lognormal distribution estimates can be made of fractions of dislodged fuel having

  12. The influence of nano silica particles on gamma-irradiation ageing of elastomers based on chlorosulphonated polyethylene and acrylonitrile butadiene rubber

    Science.gov (United States)

    Marković, G.; Marinović-Cincović, M.; Tanasić, Lj.; Jovanović, V.; Samaržija-Jovanović, S.; Vukić, N.; Budinski-Simendić, J.

    2011-12-01

    The goal of this work was to study gamma irradiation ageing of rubber blends based on acrylonitrile butadiene rubber (NBR) and chlorosulphonated polyethylene rubber (CSM) reinforced by silica nano particles. The NBR/CSM compounds (50: 50, w/w) filled with different content of filler (0-100 phr) were crosslinked by sulfur. The vulcanization characteristics were assessed using the rheometer with an oscillating disk. The vulcanizates were prepared in a hydraulic press. The obtained materials were exposed to the different irradiation doses (100, 200, 300 and 400 kGy). The mechanical properties (hardness, modulus at 100% elongation, tensile strength and elongation at break) and swelling numbers were assessed before and after gamma irradiation ageing.

  13. Signaling factors and pathways of α-particle irradiation induced bilateral bystander responses between Beas-2B and U937 cells

    International Nuclear Information System (INIS)

    Fu, Jiamei; Wang, Juan; Wang, Xiangdong; Wang, Ping; Xu, Jinping; Zhou, Cuiping; Bai, Yang; Shao, Chunlin

    2016-01-01

    Highlights: • Radiation damage of Beas-2B cells was enhanced by macrophage-mediated bilateral bystander responses. • Expressions of TNF-α and IL-8 in the α-irradiated Beas-2B cells were dependent on ERK and p38 pathways. • The neighboring U937 cells further increased the generation of TNF-α and IL-8 in the α-irradiated Beas-2B cells. • NF-κB dependent upregulation of TNF-α and IL-8 was induced in the bystander U937 cells. - Abstract: Although radiation induced bystander effects (RIBE) have been investigated for decades for their potential health risk, the underlying gene regulation is still largely unclear, especially the roles of immune system and inflammatory response in RIBE. In the present study, macrophage U937 cells and epithelial Beas-2B cells were co-cultured to disclose the cascades of bystander signaling factors and intercellular communications. After α-particle irradiation, both ERK and p38 pathways were activated in Beas-2B cells and were associated with the autocrine and paracrine signaling of TNF-α and IL-8, resulting in direct damage to the irradiated cells. Similar upregulation of TNF-α and IL-8 was induced in the bystander U937 cells after co-culture with α-irradiated Beas-2B cells. This upregulation was dependent on the activation of NF-κB pathway and was responsible for the enhanced damage of α-irradiated Beas-2B cells. Interestingly, the increased expressions of TNF-α and IL-8 mRNAs in the bystander U937 cells were clearly relayed on the activated ERK and p38 pathways in the irradiated Beas-2B cells, and the upregulation of TNF-α and IL-8 mRNAs in co-cultured Beas-2B cells was also partly due to the activated NF-κB pathway in the bystander U937 cells. With the pretreatment of U0126 (MEK1/2 inhibitor), SB203580 (p38 inhibitor) or BAY 11-7082 (NF-κB inhibitor), the aggravated damage in the α-irradiated Beas-2B cells could be largely alleviated. Our results disclosed novel signaling cascades of macrophage-mediated bilateral

  14. Signaling factors and pathways of α-particle irradiation induced bilateral bystander responses between Beas-2B and U937 cells

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiamei; Wang, Juan; Wang, Xiangdong; Wang, Ping; Xu, Jinping; Zhou, Cuiping; Bai, Yang; Shao, Chunlin, E-mail: clshao@shmu.edu.cn

    2016-07-15

    Highlights: • Radiation damage of Beas-2B cells was enhanced by macrophage-mediated bilateral bystander responses. • Expressions of TNF-α and IL-8 in the α-irradiated Beas-2B cells were dependent on ERK and p38 pathways. • The neighboring U937 cells further increased the generation of TNF-α and IL-8 in the α-irradiated Beas-2B cells. • NF-κB dependent upregulation of TNF-α and IL-8 was induced in the bystander U937 cells. - Abstract: Although radiation induced bystander effects (RIBE) have been investigated for decades for their potential health risk, the underlying gene regulation is still largely unclear, especially the roles of immune system and inflammatory response in RIBE. In the present study, macrophage U937 cells and epithelial Beas-2B cells were co-cultured to disclose the cascades of bystander signaling factors and intercellular communications. After α-particle irradiation, both ERK and p38 pathways were activated in Beas-2B cells and were associated with the autocrine and paracrine signaling of TNF-α and IL-8, resulting in direct damage to the irradiated cells. Similar upregulation of TNF-α and IL-8 was induced in the bystander U937 cells after co-culture with α-irradiated Beas-2B cells. This upregulation was dependent on the activation of NF-κB pathway and was responsible for the enhanced damage of α-irradiated Beas-2B cells. Interestingly, the increased expressions of TNF-α and IL-8 mRNAs in the bystander U937 cells were clearly relayed on the activated ERK and p38 pathways in the irradiated Beas-2B cells, and the upregulation of TNF-α and IL-8 mRNAs in co-cultured Beas-2B cells was also partly due to the activated NF-κB pathway in the bystander U937 cells. With the pretreatment of U0126 (MEK1/2 inhibitor), SB203580 (p38 inhibitor) or BAY 11-7082 (NF-κB inhibitor), the aggravated damage in the α-irradiated Beas-2B cells could be largely alleviated. Our results disclosed novel signaling cascades of macrophage-mediated bilateral

  15. Depth Dose Distribution Study within a Phantom Torso after Irradiation with a Simulated Solar Particle Event at NSRL

    Science.gov (United States)

    Berger, Thomas; Matthiae, Daniel; Koerner, Christine; George, Kerry; Rhone, Jordan; Cucinotta, Francis; Reitz, Guenther

    2010-01-01

    The adequate knowledge of the radiation environment and the doses incurred during a space mission is essential for estimating an astronaut's health risk. The space radiation environment is complex and variable, and exposures inside the spacecraft and the astronaut's body are compounded by the interactions of the primary particles with the atoms of the structural materials and with the body itself Astronauts' radiation exposures are measured by means of personal dosimetry, but there remains substantial uncertainty associated with the computational extrapolation of skin dose to organ dose, which can lead to over- or underestimation of the health risk. Comparisons of models to data showed that the astronaut's Effective dose (E) can be predicted to within about a +10% accuracy using space radiation transport models for galactic cosmic rays (GCR) and trapped radiation behind shielding. However for solar particle event (SPE) with steep energy spectra and for extra-vehicular activities on the surface of the moon where only tissue shielding is present, transport models predict that there are large differences in model assumptions in projecting organ doses. Therefore experimental verification of SPE induced organ doses may be crucial for the design of lunar missions. In the research experiment "Depth dose distribution study within a phantom torso" at the NASA Space Radiation Laboratory (NSRL) at BNL, Brookhaven, USA the large 1972 SPE spectrum was simulated using seven different proton energies from 50 up to 450 MeV. A phantom torso constructed of natural bones and realistic distributions of human tissue equivalent materials, which is comparable to the torso of the MATROSHKA phantom currently on the ISS, was equipped with a comprehensive set of thermoluminescence detectors and human cells. The detectors are applied to assess the depth dose distribution and radiation transport codes (e.g. GEANT4) are used to assess the radiation field and interactions of the radiation field

  16. SOLIS IV. Hydrocarbons in the OMC-2 FIR4 Region, a Probe of Energetic Particle Irradiation of the Region

    Science.gov (United States)

    Favre, C.; Ceccarelli, C.; López-Sepulcre, A.; Fontani, F.; Neri, R.; Manigand, S.; Kama, M.; Caselli, P.; Jaber Al-Edhari, A.; Kahane, C.; Alves, F.; Balucani, N.; Bianchi, E.; Caux, E.; Codella, C.; Dulieu, F.; Pineda, J. E.; Sims, I. R.; Theulé, P.

    2018-06-01

    We report new interferometric images of cyclopropenylidene, c-C3H2, toward the young protocluster OMC-2 FIR 4. The observations were performed at 82 and 85 GHz with the NOrthern Extended Millimeter Array (NOEMA) as part of the project Seeds Of Life In Space (SOLIS). In addition, IRAM-30 m data observations were used to investigate the physical structure of OMC-2 FIR 4. We find that the c-C3H2 gas emits from the same region where previous SOLIS observations showed bright HC5N emission. From a non-LTE analysis of the IRAM-30 m data, the c-C3H2 gas has an average temperature of ∼40 K, a H2 density of ∼3 × 105 cm‑3, and a c-C3H2 abundance relative to H2 of (7 ± 1) × 10‑12. In addition, the NOEMA observations provide no sign of significant c-C3H2 excitation temperature gradients across the region (about 3–4 beams), with T ex in the range 8 ± 3 up to 16 ± 7 K. We thus infer that our observations are inconsistent with a physical interaction of the OMC-2 FIR 4 envelope with the outflow arising from OMC-2 FIR 3, as claimed by previous studies. The comparison of the measured c-C3H2 abundance with the predictions from an astrochemical PDR model indicates that OMC-2 FIR 4 is irradiated by an FUV field ∼1000 times larger than the interstellar one, and by a flux of ionizing particles ∼4000 times larger than the canonical value of 1 × 10‑17 s‑1 from the Galaxy cosmic rays, which is consistent with our previous HC5N observations. This provides an important and independent confirmation of other studies that one, or more, source inside the OMC-2 FIR 4 region emits energetic (≥10 MeV) particles. Based on observations carried out under project number L15AA with the IRAM NOEMA Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).

  17. Arcing and rf signal generation during target irradiation by a high-energy, pulsed neutral particle beam

    International Nuclear Information System (INIS)

    Robiscoe, R.T.

    1988-02-01

    We present a theory describing the dynamics of arc discharges in bulk dielectric materials on board space-based vehicles. Such ''punch-through'' arcs can occur in target satellites irradiated by high-energy (250 MeV), pulsed (100 mA x 10 ms) neutral particle beams. We treat the arc as a capacitively limited avalanche current in the target dielectric material, and we find expressions for the arc duration, charge transport, currents, and discharge energy. These quantities are adjusted to be consistent with known scaling laws for the area of charge depleted by the arc. After a brief account of the statistical distribution of voltages at which the arc starts and stops, we calculate the signal strength and frequency spectrum of the electromagnetic radiation broadcast by the arc. We find that arcs from thick (/similar to/1 cm) targets can generate rf signals detectable up to 1000 km from the target, bu a radio receiver operating at frequency 80 MHz, bandwidth 100 kHz, and detection threshold -105 dBm. These thick-target arc signals are 10 to 20 dB above ambient noise at the receiver, and they provide target hit assessment if the signal spectrum can be sampled at several frequencies in the nominal range 30-200 MHz. Thin-target (/similar to/1 mm) arc signals are much weaker, but when they are detecable in conjunction with thick-target signals, target discrimination is possible by comparing the signal frequency spectra. 24 refs., 12 figs

  18. Benefit of particle therapy in re-irradiation of head and neck patients. Results of a multicentric in silico ROCOCO trial.

    Science.gov (United States)

    Eekers, Daniëlle B P; Roelofs, Erik; Jelen, Urszula; Kirk, Maura; Granzier, Marlies; Ammazzalorso, Filippo; Ahn, Peter H; Janssens, Geert O R J; Hoebers, Frank J P; Friedmann, Tobias; Solberg, Timothy; Walsh, Sean; Troost, Esther G C; Kaanders, Johannes H A M; Lambin, Philippe

    2016-12-01

    In this multicentric in silico trial we compared photon, proton, and carbon-ion radiotherapy plans for re-irradiation of patients with squamous cell carcinoma of the head and neck (HNSCC) regarding dose to tumour and doses to surrounding organs at risk (OARs). Twenty-five HNSCC patients with a second new or recurrent cancer after previous irradiation (70Gy) were included. Intensity-modulated proton therapy (IMPT) and ion therapy (IMIT) re-irradiation plans to a second subsequent dose of 70Gy were compared to photon therapy delivered with volumetric modulated arc therapy (VMAT). When comparing IMIT and IMPT to VMAT, the mean dose to all investigated 22 OARs was significantly reduced for IMIT and to 15 out of 22 OARs (68%) using IMPT. The maximum dose to 2% volume (D 2 ) of the brainstem and spinal cord were significantly reduced using IMPT and IMIT compared to VMAT. The data are available on www.cancerdata.org. In this ROCOCO in silico trial, a reduction in mean dose to OARs was achieved using particle therapy compared to photons in the re-irradiation of HNSCC. There was a dosimetric benefit favouring carbon-ions above proton therapy. These dose reductions may potentially translate into lower severe complication rates related to the re-irradiation. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  19. Fission-product behaviour in irradiated TRISO-coated particles: Results of the HFR-EU1bis experiment and their interpretation

    International Nuclear Information System (INIS)

    Barrachin, M.; Dubourg, R.; Groot, S. de; Kissane, M.P.; Bakker, K.

    2011-01-01

    Highlights: → The microstructure and FPs in UO 2 TRISO particles (10% FIMA, 1573 K) were studied. → Very large porosities (>10 μm) were observed in the high temperature particles. → Significant Xe and Cs releases from the kernel were observed. → Mo and Ru are mainly present in the metallic precipitates in the kernel. - Abstract: It is important to understand fission-product (FP) and kernel micro-structure evolution in TRISO-coated fuel particles. FP behaviour, while central to severe-accident evaluation, impacts: evolution of the kernel oxygen potential governing in turn carbon oxidation (amoeba effect and pressurization); particle pressurization through fission-gas release from the kernel; and coating mechanical resistance via reaction with some FPs (Pd, Cs, Sr). The HFR-Eu1bis experiment irradiated five HTR fuel pebbles containing TRISO-coated UO 2 particles and went beyond current HTR specifications (e.g., central temperature of 1523 K). This study presents ceramographic and EPMA examinations of irradiated urania kernels and coatings. Significant evolutions of the kernel (grain structure, porosity, metallic-inclusion size, intergranular bubbles) as a function of temperature are shown. Results concerning FP migration are presented, e.g., significant xenon, caesium and palladium release from the kernel, molybdenum and ruthenium mainly present in metallic precipitates. The observed FP and micro-structural evolutions are interpreted and explanations proposed. The effect of high flux rate and high temperature on fission-gas behaviour, grain-size evolution and kernel swelling is discussed. Furthermore, Cs, Mo and Zr behaviour is interpreted in connection with oxygen-potential. This paper shows that combining state-of-the-art post-irradiation examination and state-of-the-art modelling fundamentally improves understanding of HTR fuel behaviour.

  20. In vitro study of the influence of alpha particles irradiation on the pre-neoplastic transformation of rat trachea epithelial cells

    International Nuclear Information System (INIS)

    Kugel, C.

    2001-12-01

    Intern contamination by actinide oxide inhalation is potentially one health hazard during the nuclear fuel fabrication process. The aerosol particles can induce pulmonary lesions, such as epithelial cancers in particular. Their toxicity is mainly due to radiotoxicity of α irradiation. The aim of this work was to contribute, by an in vitro model, to the study of the apparition of pre-neoplastic states on epithelial cells after high LET irradiation. Primary cultures of rat tracheal epithelial cells were used. Two rat strain cells, SD TR for Sprague Dawley rats and WF TR for Wistar Furth I Fischer F344 rats, were compared after exposure to a dose range from 0 to 5 Gy. Reproductive cell death, i.e. senescent death, seems to be the main lethal way induced by α and γ irradiations. The nuclear volume of WF TR cells is higher than that of SD TR ones, explaining the higher α radiation-induced lethality of these cells. These WF TR cells are also much sensitive to dose rate and α particles energy. In the same manner, pre-neoplastic transformation rate of the cells seems to depend on the physical parameters of irradiation. But, it mainly varies as a function of cell radiosensitivity, that means cell death. In fact, the transformation rate of sensitive WF TR cells is lower than that of SD TR ones. In term of transformation for SD TR cells, dose-effect relationship fits to a linear and infra linear function after α irradiation, whereas the curve fits to linear and quadratic function after γ irradiation. The Relative Biological Efficiency (RBE) of α particles for lethality and pre-neoplastic transformation were determined for several levels of dose. A constant value of about 3 was found for RBE of lethality whatever the α dose. By contrast, the RBE of transformation has a value of about 10 up to 0.5 Gy and gradually decreases at higher doses to reach a value of 1 at 5 Gy. Similar shapes of dose-effect relationship can be observed for malignant lung tumour induction after

  1. Discussion of the origin of secondary photon and secondary ion emission during energetic particle irradiation of solids. I. The collision cascade

    International Nuclear Information System (INIS)

    Wright, R.B.; Gruen, D.M.

    1980-01-01

    Secondary photon and secondary ion emission during energetic particle irradiation of solid surfaces is assumed to arise due to excitation and de-excitation of sputtered particles originating from a collision cascade induced by the incident projectile. The excitation is postulated to occur by two alternative mechanisms: path (a), where excitation occurs at or very near the surface of the solid due to atom--atom or atom--electron collisions; and path (b), where excitation occurs as the sputtered particle leaves the solid, but is still under its influence so that electron exchange processes are permitted. Once the excited and/or ionized sputtered particle is formed nonradiative de-excitation processes are then included in the discussion which allow the excited and/or ionized particle to be de-excited and/or neutralized. The result of these nonradiative de-excitation processes is shown to provide a possible channel for the formation of new excited ''daughters'' by the de-excitation of the initial excited ''parent''. Depending on the initial excitation probability of the parent the new excited daughters are shown to contribute to various energy regions of the excited and/or ionized secondary particle energy distribution. A mathematical formalism is developed based on the neutral sputtered atom energy and velocity distributions assuming a collision cascade origin for these sputtered particles. By including various models for the excitation probability, and the survival probability for excited particles once formed to not undergo nonradiative de-excitation the resulting energy and velocity distributions of the sputtered excited and/or ionized secondary particles are calculated. These distributions are found to be a function of the emission angle depending on the model assumed for the initial excitation. From this formalism the total excited secondary particle yield may be calculated

  2. Effects of 1H + 16O Charged Particle Irradiation on Short-Term Memory and Hippocampal Physiology in a Murine Model.

    Science.gov (United States)

    Kiffer, Frederico; Carr, Hannah; Groves, Thomas; Anderson, Julie E; Alexander, Tyler; Wang, Jing; Seawright, John W; Sridharan, Vijayalakshmi; Carter, Gwendolyn; Boerma, Marjan; Allen, Antiño R

    2018-01-01

    Radiation from galactic cosmic rays (GCR) poses a significant health risk for deep-space flight crews. GCR are unique in their extremely high-energy particles. With current spacecraft shielding technology, some of the predominant particles astronauts would be exposed to are 1 H + 16 O. Radiation has been shown to cause cognitive deficits in mice. The hippocampus plays a key role in memory and cognitive tasks; it receives information from the cortex, undergoes dendritic-dependent processing and then relays information back to the cortex. In this study, we investigated the effects of combined 1 H + 16 O irradiation on cognition and dendritic structures in the hippocampus of adult male mice three months postirradiation. Six-month-old male C57BL/6 mice were irradiated first with 1 H (0.5 Gy, 150 MeV/n) and 1 h later with 16 O (0.1 Gy, 600 MeV/n) at the NASA Space Radiation Laboratory (Upton, NY). Three months after irradiation, animals were tested for hippocampus-dependent cognitive performance using the Y-maze. Upon sacrifice, molecular and morphological assessments were performed on hippocampal tissues. During Y-maze testing, the irradiated mice failed to distinguish the novel arm, spending approximately the same amount of time in all three arms during the retention trial relative to sham-treated controls. Irradiated animals also showed changes in expression of glutamate receptor subunits and synaptic density-associated proteins. 1 H + 16 O radiation compromised dendritic morphology in the cornu ammonis 1 and dentate gyrus within the hippocampus. These data indicate cognitive injuries due to 1 H + 16 O at three months postirradiation.

  3. Fission products silver, palladium, and cadmium identification in neutron-irradiated SiC TRISO particles using a Cs-Corrected HRTEM

    Energy Technology Data Exchange (ETDEWEB)

    Rooyen, I.J. van, E-mail: isabella.vanrooyen@inl.gov [Fuel Design and Development Department, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID, 83415-6188 (United States); Olivier, E.J.; Neethling, J.H. [Centre for High Resolution Electron Microscopy, Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa)

    2016-08-01

    Electron microscopy investigations of selected coated particles from the first advanced gas reactor experiment at Idaho National Laboratory provided important information on fission product distribution and chemical composition in the silicon-carbide (SiC) layer. Silver precipitates were nano-sized, and therefore high-resolution transmission electron microscopy (HRTEM) was used to provide more information at the atomic level. Based on gamma-ray analysis, this particle which was irradiated to an average burnup of 19.38% fissions per initial metal atom, may have released as much as 10% of its available Ag-110 m inventory during irradiation. The HRTEM investigation focused on silver, palladium, and cadmium due to interest in silver transport mechanisms and possible correlation with palladium and silver previously found. Palladium, silver, and cadmium were found to co-exist in some of the SiC grain boundaries and triple junctions. This study confirmed palladium both at inter and intragranular sites. Phosphor was identified in SiC grain boundaries and triple points. - Highlights: • First high resolution electron microscopy fission product nano-structural locations of irradiated TRISO coated particles. • Pd observed inside SiC grains in proximity to planar defects e.g. stacking faults. • Ag co-exists with Pd and Cd only may suggest a Pd-assisted transport mechanism. • First finding of neutron transmutation product P, in SiC layer of TRISO coated particles. No direct link to Ag transport. • No significant Pd corrosion of SiC observed even at this high resolution images.

  4. Effects of 5.4 MeV alpha-particle irradiation on the electrical properties of nickel Schottky diodes on 4H–SiC

    Energy Technology Data Exchange (ETDEWEB)

    Omotoso, E. [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa); Department of Physics, Obafemi Awolowo University, Ile-Ife 220005 (Nigeria); Meyer, W.E.; Auret, F.D.; Paradzah, A.T.; Diale, M.; Coelho, S.M.M.; Janse van Rensburg, P.J.; Ngoepe, P.N.M. [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa)

    2015-12-15

    Current–voltage, capacitance–voltage and conventional deep level transient spectroscopy at temperature ranges from 40 to 300 K have been employed to study the influence of alpha-particle irradiation from an {sup 241}Am source on Ni/4H–SiC Schottky contacts. The nickel Schottky barrier diodes were resistively evaporated on n-type 4H–SiC samples of doping density of 7.1 × 10{sup 15} cm{sup −3}. It was observed that radiation damage caused an increase in ideality factors of the samples from 1.04 to 1.07, an increase in Schottky barrier height from 1.25 to 1.31 eV, an increase in series resistance from 48 to 270 Ω but a decrease in saturation current density from 55 to 9 × 10{sup −12} A m{sup −2} from I–V plots at 300 K. The free carrier concentration of the sample decreased slightly after irradiation. Conventional DLTS showed peaks due to four deep levels for as-grown and five deep levels after irradiation. The Richardson constant, as determined from a modified Richardson plot assuming a Gaussian distribution of barrier heights for the as-grown and irradiated samples were 133 and 151 A cm{sup −2} K{sup −2}, respectively. These values are similar to literature values.

  5. Catalytic property of an indium-deposited powder-type material containing silicon and its dependence on the dose of indium nano-particles irradiated by a pulse arc plasma process

    Directory of Open Access Journals (Sweden)

    Satoru Yoshimura

    2017-06-01

    Full Text Available Indium nano-particle irradiations onto zeolite powders were carried out using a pulse arc plasma source system. X-ray photoelectron spectroscopic and scanning electron microscopic studies of an indium irradiated zeolite sample revealed that indium nano-particles were successfully deposited on the sample. Besides, the sample was found to be capable of catalyzing an organic chemical reaction (i.e., Friedel-Crafts alkylation. Then, we examined whether or not the catalytic ability depends on the irradiated indium dose, having established the optimal indium dose for inducing the catalytic effect.

  6. Analysis of irradiation-induced stresses in coating layers of coated fuel particles for the High Temperature Engineering Test Reactor (HTTR)

    International Nuclear Information System (INIS)

    Hayashi, Kimio; Kikuchi, Teruo; Fukuda, Kousaku; Sato, Sadao; Toyota, Junji; Shiozawa, Shusaku; Sawa, Kazuhiro; Kashimura, Satoru.

    1991-07-01

    Irradiation-induced stresses in coating layers of coated fuel particles were analyzed by the MICROS-2 code for the fuels of the High Temperature Engineering Test Reactor (HTTR) under its operating conditions. The analyses were made on the standard core fuel (A-type) and the test fuels comprising the advanced SiC-coated particle fuel (B-1 type) and the ZrC-coated particle fuel (B-2 type). For the B-1 type fuel, the stresses were relieved due to the thicker buffer and SiC layers than for the A type fuel. The slightly decreased thickness of the fourth layer for the B-1 type than for the A type fuel had no significant effect on the stresses. As for the B-2 type fuel, almost the same results as for the B-1 type were obtained under an assumption that the ZrC layer as well as the SiC layer undergoes negligible dimension change within the analysis conditions. The obtained results indicated that the B-1 and B-2 type fuels are better than the A type fuel in terms of integrity against the irradiation-induced stresses. Finally, research subjects for development of the analysis code on the fuel behavior are discussed. (author)

  7. Bactericidal effect of blue LED light irradiated TiO2/Fe3O4 particles on fish pathogen in seawater

    International Nuclear Information System (INIS)

    Cheng, T.C.; Yao, K.S.; Yeh, N.; Chang, C.I.; Hsu, H.C.; Gonzalez, F.; Chang, C.Y.

    2011-01-01

    This study uses blue LED light (λ max = 475 nm) activated TiO 2 /Fe 3 O 4 particles to evaluate the particles' photocatalytic activity efficiency and bactericidal effects in seawater of variable salinities. Different TiO 2 to Fe 3 O 4 mole ratios have been synthesized using sol-gel method. The synthesized particles contain mainly anatase TiO 2 , Fe 3 O 4 and FeTiO 3 . The study has identified TiO 2 /Fe 3 O 4 's bactericidal effect to marine fish pathogen (Photobacterium damselae subsp. piscicida BCRC17065) in seawater. The SEM photo reveals the surface destruction in bacteria incubated with blue LED irradiated TiO 2 /Fe 3 O 4 . The result of this study indicates that 1) TiO 2 /Fe 3 O 4 acquires photocatalytic activities in both the freshwater and the seawater via blue LED irradiation, 2) higher photocatalytic activities appear in solutions of higher TiO 2 /Fe 3 O 4 mole ratio, and 3) photocatalytic activity decreases as salinity increases. These results suggest that the energy saving blue LED light is a feasible light source to activate TiO 2 /Fe 3 O 4 photocatalytic activities in both freshwater and seawater.

  8. Recent observations on the evolution of secondary-phase particles in zircaloy-2 under irradiation in a BWR to high burn-up

    International Nuclear Information System (INIS)

    Abolhassani, S.; Graber, T.; Gavillet, D.; Groeschel, F.

    2000-01-01

    The influence of radiation on the corrosion of the fuel claddings in a Light Water Reactor (LWR) has been the subject of many investigations, and different aspects of the overall phenomena have been studied by different techniques. Analysis of the evolution of Secondary-Phase Particles (SPPs) for different periods of immersion of the cladding in the reactor enables the rate of corrosion to the structure of the material to be correlated. In the case of Zircaloy-2 in a Boiling Water Reactor (BWR), SPPs are dissolved under irradiation, and their dissolution affects the rate of oxidation and other correlated phenomena. In recent studies, the Zircaloy-2 in claddings loaded in the Leibstadt BWR are analysed after one, three and five cycles. Results are presented, and give an account of the changes which occurred in the materials under irradiation. (authors)

  9. Recent observations on the evolution of secondary-phase particles in zircaloy-2 under irradiation in a BWR to high burn-up

    Energy Technology Data Exchange (ETDEWEB)

    Abolhassani, S.; Graber, T.; Gavillet, D.; Groeschel, F

    2000-07-01

    The influence of radiation on the corrosion of the fuel claddings in a Light Water Reactor (LWR) has been the subject of many investigations, and different aspects of the overall phenomena have been studied by different techniques. Analysis of the evolution of Secondary-Phase Particles (SPPs) for different periods of immersion of the cladding in the reactor enables the rate of corrosion to the structure of the material to be correlated. In the case of Zircaloy-2 in a Boiling Water Reactor (BWR), SPPs are dissolved under irradiation, and their dissolution affects the rate of oxidation and other correlated phenomena. In recent studies, the Zircaloy-2 in claddings loaded in the Leibstadt BWR are analysed after one, three and five cycles. Results are presented, and give an account of the changes which occurred in the materials under irradiation. (authors)

  10. Radiation-thermal effects change of physico-mechanical properties in reactor materials irradiated with neutrons and energetic charged particles

    International Nuclear Information System (INIS)

    Hofman, A.

    1999-01-01

    In the first part of the report (chapter 1) the earlier results of the important scientific and technological investigations which were performed in the seventies years in Poland have been presented. They concerned the fabrication, corrosion, mechanical properties of materials for research and power reactors. Being of the general survey character, the chapter includes own, original results of research of thermal irradiation effects on microstructure evolution phase transformations and mechanical properties of reactor materials. The kinetics of isothermal transformation β→α in U-Cr 0.4% wt. alloy has been studied. Factors affecting stress-corrosion cracking of zirconium in iodine vapour have been investigated. The rings and loops for irradiation specimens and Hot Laboratory for postirradiation examination of construction materials is described. In the second part (chapters 2, 3, 4, 5) performed the investigations and simulations of radiation damage in metals by heavy ion beams (E > 1 MeV/a.m.n.) were described scientific base and technical problems of the method of irradiation of heavy ions and of the examination of irradiated samples is presented. It is followed by a summary of the results of simulation and reactor experiments on different materials. Radiation hardening of a number metals (Al, Zr, Cu, Ni, U) irradiated by heavy ion and neutrons, mechanical properties and microstructural evolution in ion and neutron irradiated austenitic stainless steel is described. The last chapter is a description of practical aspects of the presented studies in nuclear science and technology. (author)

  11. No significant level of inheritable interchromosomal aberrations in the progeny of bystander primary human fibroblasts after alpha particle irradiation

    Science.gov (United States)

    Hu, Burong; Zhu, Jiayun; Zhou, Hongning; Hei, Tom K.

    2013-02-01

    A major concern for bystander effects is the probability that normal healthy cells adjacent to the irradiated cells become genomically unstable and undergo further carcinogenesis after therapeutic irradiation or space mission where astronauts are exposed to low dose of heavy ions. Genomic instability is a hallmark of cancer cells. In the present study, two irradiation protocols were performed in order to ensure pure populations of bystander cells and the genomic instability in their progeny were investigated. After irradiation, chromosomal aberrations of cells were analyzed at designated time points using G2 phase premature chromosome condensation (G2-PCC) coupled with Giemsa staining and with multiplex fluorescent in situ hybridization (mFISH). Our Giemsa staining assay demonstrated that elevated yields of chromatid breaks were induced in the progeny of pure bystander primary fibroblasts up to 20 days after irradiation. mFISH assay showed no significant level of inheritable interchromosomal aberrations were induced in the progeny of the bystander cell groups, while the fractions of gross aberrations (chromatid breaks or chromosomal breaks) significantly increased in some bystander cell groups. These results suggest that genomic instability occurred in the progeny of the irradiation associated bystander normal fibroblasts exclude the inheritable interchromosomal aberration.

  12. Pixel pitch and particle energy influence on the dark current distribution of neutron irradiated CMOS image sensors.

    Science.gov (United States)

    Belloir, Jean-Marc; Goiffon, Vincent; Virmontois, Cédric; Raine, Mélanie; Paillet, Philippe; Duhamel, Olivier; Gaillardin, Marc; Molina, Romain; Magnan, Pierre; Gilard, Olivier

    2016-02-22

    The dark current produced by neutron irradiation in CMOS Image Sensors (CIS) is investigated. Several CIS with different photodiode types and pixel pitches are irradiated with various neutron energies and fluences to study the influence of each of these optical detector and irradiation parameters on the dark current distribution. An empirical model is tested on the experimental data and validated on all the irradiated optical imagers. This model is able to describe all the presented dark current distributions with no parameter variation for neutron energies of 14 MeV or higher, regardless of the optical detector and irradiation characteristics. For energies below 1 MeV, it is shown that a single parameter has to be adjusted because of the lower mean damage energy per nuclear interaction. This model and these conclusions can be transposed to any silicon based solid-state optical imagers such as CIS or Charged Coupled Devices (CCD). This work can also be used when designing an optical imager instrument, to anticipate the dark current increase or to choose a mitigation technique.

  13. G2M arrest and apoptosis in murine T lymphoma cells following exposure to 212Bi alpha particle irradiation

    International Nuclear Information System (INIS)

    Palayoor, S.T.; Humm, J.L.; Macklis, R.M.

    1993-01-01

    Asynchronous exponentially growing EL4 murine T lymphoma cells were exposed either to high LET α-radiation from 212 Bi-DTPA or to γ-radiation from a 137 Cs source. Radiation-induced cell cycle perturbation was studied by flow cytometry. Alpha irradiation, like γ, transiently arrested cells in the G2M phase in a dose-dependent manner. The maximum percentages of cells accumulated in G2M 18 h after α- and γ-irradiation were comparable, though the dose-response relationships differed. The ''RBE'' value for G2M block for α- versus γ-radiation was approx. 4. (author)

  14. Membrane-Dependent Bystander Effect Contributes to Amplification of the Response to Alpha-Particle Irradiation in Targeted and Nontargeted Cells

    International Nuclear Information System (INIS)

    Hanot, Maite; Hoarau, Jim; Carriere, Marie; Angulo, Jaime F.; Khodja, Hicham

    2009-01-01

    Purpose: Free radicals are believed to play an active role in the bystander response. This study investigated their origin as well as their temporal and spatial impacts in the bystander effect. Methods and Materials: We employed a precise alpha-particle microbeam to target a small fraction of subconfluent osteoblastic cells (MC3T3-E1). γH2AX-53BP1 foci, oxidative metabolism changes, and micronuclei induction in targeted and bystander cells were assessed. Results: Cellular membranes and mitochondria were identified as two distinct reactive oxygen species producers. The global oxidative stress observed after irradiation was significantly attenuated after cells were treated with filipin, evidence for the primal role of membrane in the bystander effect. To determine the membrane's impact at a cellular level, micronuclei yield was measured when various fractions of the cell population were individually targeted while the dose per cell remained constant. Induction of micronuclei increased in bystander cells as well as in targeted cells and was attenuated by filipin treatment, demonstrating a role for bystander signals between irradiated cells in an autocrine/paracrine manner. Conclusions: A complex interaction of direct irradiation and bystander signals leads to a membrane-dependent amplification of cell responses that could influence therapeutic outcomes in tissues exposed to low doses or to environmental exposure.

  15. Differential superiority of heavy charged-particle irradiation to x-rays: Studies on biological effectivenes and side effect mechanisms in multicellular tumor and normal tissue models

    Directory of Open Access Journals (Sweden)

    Stefan eWalenta

    2016-02-01

    Full Text Available This review is focused on the radiobiology of carbon ions compared to x-rays using multicellular models of tumors and normal mucosa. The first part summarizes basic radiobiological effects, as observed in cancer cells. The second, more clinically oriented part of the review deals with radiation-induced cell migration and mucositis.Multicellular spheroids (MCS from V79 hamster cells were irradiated with x-rays or carbon ions under ambient or restricted oxygen supply conditions. Oxygen enhancement ratios (OER were 2.9, 2.8, and 1.4 for irradiation with photons, 12C+6 in the plateau region, and 12C+6 in the Bragg peak, respectively. A relative biological effectiveness (RBE of 4.3 and 2.1 for ambient pO2 and hypoxia was obtained, respectively. The high effectiveness of carbon ions was reflected by an enhanced accumulation of cells in G2/M, and a dose-dependent massive induction of apoptosis. Clinically relevant doses (3 Gy of x-rays induced an increase in migratory activity of U87 but not of LN229 or HCT116 tumor cells. Such an increase in cell motility following irradiation in situ could be the source of recurrence. In contrast, carbon ion treatment was associated with a dose-dependent decrease in migration with all cell lines and under all conditions investigated. The radiation-induced loss of cell motility was correlated, in most cases, with corresponding changes in 1 integrin expression. Unlike with particles, the photon-induced increase in cell migration was paralleled by an elevated phosphorylation status of the epidermal growth factor receptor (EGFR and AKT-ERK1/2 pathway. Comparing the gene toxicity of x-rays with that of particles using the gamma-H2AX technique in organotypic cultures of the oral mucosa, the superior effectiveness of heavy ions was confirmed by a two-fold higher number of foci per nucleus. Pro-inflammatory signs, however, were similar for both treatment modalities, e. g., the activation of NFkappaB, and the release of IL

  16. Differential Superiority of Heavy Charged-Particle Irradiation to X-Rays: Studies on Biological Effectiveness and Side Effect Mechanisms in Multicellular Tumor and Normal Tissue Models

    Science.gov (United States)

    Walenta, Stefan; Mueller-Klieser, Wolfgang

    2016-01-01

    This review is focused on the radiobiology of carbon ions compared to X-rays using multicellular models of tumors and normal mucosa. The first part summarizes basic radiobiological effects, as observed in cancer cells. The second, more clinically oriented part of the review, deals with radiation-induced cell migration and mucositis. Multicellular spheroids from V79 hamster cells were irradiated with X-rays or carbon ions under ambient or restricted oxygen supply conditions. Reliable oxygen enhancement ratios could be derived to be 2.9, 2.8, and 1.4 for irradiation with photons, 12C+6 in the plateau region, and 12C+6 in the Bragg peak, respectively. Similarly, a relative biological effectiveness of 4.3 and 2.1 for ambient pO2 and hypoxia was obtained, respectively. The high effectiveness of carbon ions was reflected by an enhanced accumulation of cells in G2/M and a dose-dependent massive induction of apoptosis. These data clearly show that heavy charged particles are more efficient in sterilizing tumor cells than conventional irradiation even under hypoxic conditions. Clinically relevant doses (3 Gy) of X-rays induced an increase in migratory activity of U87 but not of LN229 or HCT116 tumor cells. Such an increase in cell motility following irradiation in situ could be the source of recurrence. In contrast, carbon ion treatment was associated with a dose-dependent decrease in migration with all cell lines and under all conditions investigated. The radiation-induced loss of cell motility was correlated, in most cases, with corresponding changes in β1 integrin expression. The photon-induced increase in cell migration was paralleled by an elevated phosphorylation status of the epidermal growth factor receptor and AKT-ERK1/2 pathway. Such a hyperphosphorylation did not occur during 12C+6 irradiation under all conditions registered. Comparing the gene toxicity of X-rays with that of particles using the γH2AX technique in organotypic cultures of the oral mucosa, the

  17. Differential Superiority of Heavy Charged-Particle Irradiation to X-Rays: Studies on Biological Effectiveness and Side Effect Mechanisms in Multicellular Tumor and Normal Tissue Models.

    Science.gov (United States)

    Walenta, Stefan; Mueller-Klieser, Wolfgang

    2016-01-01

    This review is focused on the radiobiology of carbon ions compared to X-rays using multicellular models of tumors and normal mucosa. The first part summarizes basic radiobiological effects, as observed in cancer cells. The second, more clinically oriented part of the review, deals with radiation-induced cell migration and mucositis. Multicellular spheroids from V79 hamster cells were irradiated with X-rays or carbon ions under ambient or restricted oxygen supply conditions. Reliable oxygen enhancement ratios could be derived to be 2.9, 2.8, and 1.4 for irradiation with photons, (12)C(+6) in the plateau region, and (12)C(+6) in the Bragg peak, respectively. Similarly, a relative biological effectiveness of 4.3 and 2.1 for ambient pO2 and hypoxia was obtained, respectively. The high effectiveness of carbon ions was reflected by an enhanced accumulation of cells in G2/M and a dose-dependent massive induction of apoptosis. These data clearly show that heavy charged particles are more efficient in sterilizing tumor cells than conventional irradiation even under hypoxic conditions. Clinically relevant doses (3 Gy) of X-rays induced an increase in migratory activity of U87 but not of LN229 or HCT116 tumor cells. Such an increase in cell motility following irradiation in situ could be the source of recurrence. In contrast, carbon ion treatment was associated with a dose-dependent decrease in migration with all cell lines and under all conditions investigated. The radiation-induced loss of cell motility was correlated, in most cases, with corresponding changes in β1 integrin expression. The photon-induced increase in cell migration was paralleled by an elevated phosphorylation status of the epidermal growth factor receptor and AKT-ERK1/2 pathway. Such a hyperphosphorylation did not occur during (12)C(+6) irradiation under all conditions registered. Comparing the gene toxicity of X-rays with that of particles using the γH2AX technique in organotypic cultures of the oral

  18. Bactericidal effect of blue LED light irradiated TiO{sub 2}/Fe{sub 3}O{sub 4} particles on fish pathogen in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, T.C. [Department of Tropical Agriculture and International Cooperation, National Pingtung University of Science and Technology, Taiwan (China); Yao, K.S. [Department of Horticulture, National Taitung Junior College, Taiwan (China); Yeh, N. [Mingdao University, Taiwan (China); Chang, C.I. [Aquaculture Division, Fisheries Research Institute, Council of Agriculture, Taiwan (China); Hsu, H.C. [Department of Life Science, Mingdao University, Taiwan (China); Gonzalez, F. [Department of Tropical Agriculture and International Cooperation, National Pingtung University of Science and Technology, Taiwan (China); Chang, C.Y., E-mail: cyc1136@yahoo.com.tw [Center of General Education, National Taitung Junior College, Taiwan (China)

    2011-05-31

    This study uses blue LED light ({lambda}{sub max} = 475 nm) activated TiO{sub 2}/Fe{sub 3}O{sub 4} particles to evaluate the particles' photocatalytic activity efficiency and bactericidal effects in seawater of variable salinities. Different TiO{sub 2} to Fe{sub 3}O{sub 4} mole ratios have been synthesized using sol-gel method. The synthesized particles contain mainly anatase TiO{sub 2}, Fe{sub 3}O{sub 4} and FeTiO{sub 3}. The study has identified TiO{sub 2}/Fe{sub 3}O{sub 4}'s bactericidal effect to marine fish pathogen (Photobacterium damselae subsp. piscicida BCRC17065) in seawater. The SEM photo reveals the surface destruction in bacteria incubated with blue LED irradiated TiO{sub 2}/Fe{sub 3}O{sub 4}. The result of this study indicates that 1) TiO{sub 2}/Fe{sub 3}O{sub 4} acquires photocatalytic activities in both the freshwater and the seawater via blue LED irradiation, 2) higher photocatalytic activities appear in solutions of higher TiO{sub 2}/Fe{sub 3}O{sub 4} mole ratio, and 3) photocatalytic activity decreases as salinity increases. These results suggest that the energy saving blue LED light is a feasible light source to activate TiO{sub 2}/Fe{sub 3}O{sub 4} photocatalytic activities in both freshwater and seawater.

  19. Characteristics of the behavior of rare-earth oxides and composites on their base by charged particles and neutrons irradiated

    International Nuclear Information System (INIS)

    Tuseev, T.; Aksenova, T.I.; Berdauletov, A.K.

    2000-01-01

    In this work the results of comparative investigation of adsorption curves versus REM order number (La, Ce, Nd, Pr, Gd) and dose neutron irradiation are presented. It is discovered that the original REM oxides have high adsorption capacity both for donor gases and for acceptor ones. The adsorption capacity for oxygen and hydrogen becomes lower when the REM order number is higher, but it is contrary for water molecules. The obtained results showed that adsorption properties of REM oxides were changing on identical laws. But oxides of metals, having anomalous properties (variable valency, high cross-section capture) revealed especial adsorption properties under irradiation. In the time of consideration of possible mechanism of radiation - stimulated gas adsorption on oxide surface it is necessary to take in attention both the formation of radiation defects in crystal lattice and the characteristics of electron structure and presence of 4 f - cover in rare-earth metals

  20. Differences in photoluminescence properties and thermal degradation between nanoparticle and bulk particle BaMgAl10O17:Eu2+ phosphors under UV?VUV irradiation.

    Science.gov (United States)

    Liu, Bitao; Xin, Shuangyu; Li, Fenghua; Zhang, Jiachi; Wang, Yuhua

    2014-05-01

    BaMgAl10O17:Eu2+ (BAM) phosphors used for plasma display panels and three-band fluorescence lamps are exposed to an oxidizing environment at about 500 degrees C, which is currently unavoidable in actual applications. We investigated the mechanism of the luminance degradation of BAM caused by annealing at 500 degrees C based on the difference in luminance degradation of bulk particle and nanoparticle samples under various excitation source irradiations. When the samples were excited by the different light sources, more than 30% degradation of luminance occurred under 147 nm while less than 10% degradation occurred under 254 nm both for nanoparticle and bulk particle samples. In addition, the luminescence degradation of nanophosphors shows a different tendency compared to the bulk phosphors. With a model based on the particle size and excitation light penetration depth, we demonstrate that the degradation is still mainly ascribed to the oxidized of divalent Eu. The differences in luminescence properties between nanophosphors and bulk phosphors are also illustrated by this model. As a result, the potential industrial applications of nanophosphors are evaluated.

  1. Differential radiosensitivity phenotypes of DNA-PKcs mutations affecting NHEJ and HRR systems following irradiation with gamma-rays or very low fluences of alpha particles.

    Science.gov (United States)

    Lin, Yu-Fen; Nagasawa, Hatsumi; Little, John B; Kato, Takamitsu A; Shih, Hung-Ying; Xie, Xian-Jin; Wilson, Paul F; Brogan, John R; Kurimasa, Akihiro; Chen, David J; Bedford, Joel S; Chen, Benjamin P C

    2014-01-01

    We have examined cell-cycle dependence of chromosomal aberration induction and cell killing after high or low dose-rate γ irradiation in cells bearing DNA-PKcs mutations in the S2056 cluster, the T2609 cluster, or the kinase domain. We also compared sister chromatid exchanges (SCE) production by very low fluences of α-particles in DNA-PKcs mutant cells, and in homologous recombination repair (HRR) mutant cells including Rad51C, Rad51D, and Fancg/xrcc9. Generally, chromosomal aberrations and cell killing by γ-rays were similarly affected by mutations in DNA-PKcs, and these mutant cells were more sensitive in G1 than in S/G2 phase. In G1-irradiated DNA-PKcs mutant cells, both chromosome- and chromatid-type breaks and exchanges were in excess than wild-type cells. For cells irradiated in late S/G2 phase, mutant cells showed very high yields of chromatid breaks compared to wild-type cells. Few exchanges were seen in DNA-PKcs-null, Ku80-null, or DNA-PKcs kinase dead mutants, but exchanges in excess were detected in the S2506 or T2609 cluster mutants. SCE induction by very low doses of α-particles is resulted from bystander effects in cells not traversed by α-particles. SCE seen in wild-type cells was completely abolished in Rad51C- or Rad51D-deficient cells, but near normal in Fancg/xrcc9 cells. In marked contrast, very high levels of SCEs were observed in DNA-PKcs-null, DNA-PKcs kinase-dead and Ku80-null mutants. SCE induction was also abolished in T2609 cluster mutant cells, but was only slightly reduced in the S2056 cluster mutant cells. Since both non-homologous end-joining (NHEJ) and HRR systems utilize initial DNA lesions as a substrate, these results suggest the possibility of a competitive interference phenomenon operating between NHEJ and at least the Rad51C/D components of HRR; the level of interaction between damaged DNA and a particular DNA-PK component may determine the level of interaction of such DNA with a relevant HRR component.

  2. Probabilistic methods for the simulation of fuel particles behavior under irradiation; Apport des methodes probabilistes dans la simulation du comportement sous irradiation du combustible a particules

    Energy Technology Data Exchange (ETDEWEB)

    Cannamela, C

    2007-09-15

    This work is devoted to the evaluation of mathematical expectations in the context of structural reliability. We seek a failure probability estimate (that we assume low), taking into account the uncertainty of influential parameters of the System. Our goal is to reach a good compromise between the accuracy of the estimate and the associated computational cost. This approach is used to estimate the failure probability of fuel particles from a HTR-type nuclear reactor. This estimate is obtain by means of costly numerical simulations. We consider different probabilistic methods to tackle the problem. First, we consider a variance reducing Monte Carlo method: importance sampling. For the parametric case, we propose adaptive algorithms in order to build a series of probability densities that will eventually converge to optimal importance density. We then present several estimates of the mathematical expectation based on this series of densities. Next, we consider a multi-level method using Monte Carlo Markov Chain algorithm. Finally, we turn our attention to the related problem of quantile estimation (non extreme) of physical output from a large-scale numerical code. We propose a controlled stratification method. The random input parameters are sampled in specific regions obtained from surrogate of the response. The estimation of the quantile is then computed from this sample. (author)

  3. INVESTIGATION OF NONAXISYMMETRIC STRESS STATE FOR QUASI-STATIC THERMAL POWER LOADING UNDER CONDITIONS OF HIGHEST-ENERGY PARTICLE IRRADIATION

    Directory of Open Access Journals (Sweden)

    A. V. Chigarev

    2013-01-01

    Full Text Available The paper contains a virtual modeling 2D(r, θ for deformation of singly-connected cylindrical solid under conditions of thermo-irradiation impact. Influence of a circumferential distortion on nonaxisymmetric strain-stress state for various values of temperature amplitudes has been investigated in the paper. A solid cylinder  with internal heat sources has been considered as a model body. Properties of the model body correspond to cermet fuel (40 % UO2 + 60 % Cr. 

  4. Interactions of secondary particles with thorium samples in the setup QUINTA irradiated with 6 GeV deuterons

    Energy Technology Data Exchange (ETDEWEB)

    Khushvaktov, J., E-mail: khushvaktov@jinr.ru [Joint Institute for Nuclear Research, Dubna (Russian Federation); Institute of Nuclear Physics ASRU, Tashkent (Uzbekistan); Adam, J. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Nuclear Physics Institute ASCR PRI (Czech Republic); Baldin, A.A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Institute for Advanced Studies “OMEGA”, Dubna (Russian Federation); Chilap, V.V. [Center of Physical and Technical Projects “Atomenergomash”, Moscow (Russian Federation); Furman, V.I.; Sagimbaeva, F.; Solnyshkin, A.A.; Stegailov, V.I.; Tichy, P.; Tsoupko-Sitnikov, V.M.; Tyutyunnikov, S.I.; Vespalec, R. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Vrzalova, J. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Nuclear Physics Institute ASCR PRI (Czech Republic); Yuldashev, B.S. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Institute of Nuclear Physics ASRU, Tashkent (Uzbekistan); Wagner, V. [Nuclear Physics Institute ASCR PRI (Czech Republic); Zavorka, L.; Zeman, M. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    2016-08-15

    The natural uranium assembly, QUINTA, was irradiated with 6 GeV deuterons. The {sup 232}Th samples were placed at the central axis of the setup QUINTA. The spectra of gamma rays emitted by the activated {sup 232}Th samples have been analysed and more than one hundred nuclei produced have been identified. For each of those products, reaction rates have been determined. The ratio of the weight of produced {sup 233}U to {sup 232}Th is presented. Experimental results were compared with the results of Monte Carlo simulations by FLUKA code.

  5. Interactions of secondary particles with thorium samples in the setup QUINTA irradiated with 6-GeV deuterons

    International Nuclear Information System (INIS)

    Khushvaktov, J.H.; Yuldashev, B.S.; Adam, J.; Vrzalova, J.; Baldin, A.A.; Chilap, V.V.; Furman, V.I.; Sagimbaeva, F.; Solnyshkin, A.A.; Stegailov, V.I.; Tichy, P.; Tsoupko-Sitnikov, V.M.; Tyutyunnikov, S.I.; Vespalec, R.; Zavorka, L.; Wagner, V.; Zeman, M.

    2016-01-01

    The natural uranium assembly, QUINTA, was irradiated with 6-GeV deuterons. The 232 Th samples were placed at the central axis of the setup QUINTA. The spectra of gamma rays emitted by the activated 232 Th samples have been analysed, and more than one hundred nuclei produced have been identified. For each of those products, reaction rates have been determined. The ratio of the weight of produced 233 U to that of 232 Th is presented. Experimental results were compared with the results of Monte Carlo simulations by the FLUKA code. [ru

  6. Apparatus for real-time size and speed measurements of blow-off particles from pulsed irradiation experiments

    International Nuclear Information System (INIS)

    Von Benken, C.; Johnson, E.A.; Nordberg, M.

    1989-01-01

    The authors present an apparatus capable of detecting micron sized particles traveling at speeds up to 10 6 cm/sec. The apparatus uses light scattering methods with automated data processing. Data generated by this apparatus should be extremely useful in radiation damage studies of components in contamination sensitive optical systems

  7. Pigment pattern in jaguar/obelix zebrafish is caused by a Kir7.1 mutation: implications for the regulation of melanosome movement.

    Directory of Open Access Journals (Sweden)

    Motoko Iwashita

    2006-11-01

    Full Text Available Many animals have a variety of pigment patterns, even within a species, and these patterns may be one of the driving forces of speciation. Recent molecular genetic studies on zebrafish have revealed that interaction among pigment cells plays a key role in pattern formation, but the mechanism of pattern formation is unclear. The zebrafish jaguar/obelix mutant has broader stripes than wild-type fish. In this mutant, the development of pigment cells is normal but their distribution is altered, making these fish ideal for studying the process of pigment pattern formation. Here, we utilized a positional cloning method to determine that the inwardly rectifying potassium channel 7.1 (Kir7.1 gene is responsible for pigment cell distribution among jaguar/obelix mutant fish. Furthermore, in jaguar/obelix mutant alleles, we identified amino acid changes in the conserved region of Kir7.1, each of which affected K(+ channel activity as demonstrated by patch-clamp experiments. Injection of a bacterial artificial chromosome containing the wild-type Kir7.1 genomic sequence rescued the jaguar/obelix phenotype. From these results, we conclude that mutations in Kir7.1 are responsible for jaguar/obelix. We also determined that the ion channel function defect of melanophores expressing mutant Kir7.1 altered the cellular response to external signals. We discovered that mutant melanophores cannot respond correctly to the melanosome dispersion signal derived from the sympathetic neuron and that melanosome aggregation is constitutively activated. In zebrafish and medaka, it is well known that melanosome aggregation and subsequent melanophore death increase when fish are kept under constant light conditions. These observations indicate that melanophores of jaguar/obelix mutant fish have a defect in the signaling pathway downstream of the alpha2-adrenoceptor. Taken together, our results suggest that the cellular defect of the Kir7.1 mutation is directly responsible for

  8. Antioxidant ability and radiosensitivity in malignant transformed human bronchial epithelial cell line BEP2D induced by α-particle irradiation

    International Nuclear Information System (INIS)

    Gou Qiao; Zhang Wei; Wang Chunyan; Su Xu

    2011-01-01

    Objective: To investigate the antioxidant ability and radiosensitivity in the malignant transformed human bronchial epithelial cell line BEP2D induced by α-particle exposure. Methods: Glutathione Peroxidase (GPX), Catalase (CAT) and Glutathione (GSH) assay kits were employed to detect GPX and CAT enzyme abilities and the levels of GSH in BEP2D, RH21 (passage 21 of α-particle-irradiated BEP2D cells), and BERP35T-1 cells (derived from nude mice bearing malignant transformed cells generated from cells of passage 35 of α-particle-irradiated BEP2D cells). MTT assay were used to test the growth rate of BEP2D, RH21 and BERP35T-1 cells treated with 0, 30, 60, 90, 120, and 150 μmoL/L H 2 O 2 . Colony-forming test and MTT assay were used to examine the cell survival fraction and the growth rate of BEP2D, RH21 and BERP35T-1 cells exposed to 0, 2, 4, and 8 Gy of γ-rays,respectively. Results: GPX and CAT enzyme activities in RH21 and BERP35T-1 cells were obviously lower than in BEP2D (t=5.75-67.92, P<0.05). CAT enzyme activity in BERP35T-1 was lower than that in RH21 cells (t=22.25, P<0.01). Compared to BEP2D cells, decreased level of GSH was detected in BERP35T-1 cells (t=7.76, P<0.05), but there was no change in RH21. After treatment with 30, 60, 90, 120, and 150 μmol/L H 2 O 2 , the growth rates of BEP2D were all higher than those of BERP35T-1 cells (t=10.37-58.36, P<0.01). Meanwhile,the growth rates of BEP2D were all higher than those of RH21 cells after treatment with 60, 90, 120, and 150 μ mol/L H 2 O 2 (t =29.90-84.68, P<0.01). In addition,compared to BEP2D cells,decreased cell survival fraction and growth rate of BERP35T-1 cells were observed after irradiation with 2, 4, and 8 Gy of y-rays (t=5.87-34.17, P<0.05). The cell survival fraction and growth rate of RH21 were all lower than those of BEP2D cells at 4 and 8 Gy post-irradiation (t=6.33- 45.00, P<0.05). Conclusion: The function of antioxidant system decreased in the α-particle-induced transformed cells

  9. In Situ Gamma Irradiation and Thermal Treatment Effects on the Static Bending Properties of Particle boards Based on Waste Materials and Different Adhesives

    International Nuclear Information System (INIS)

    Khafaga, M.R.; El-Naggar, A.M.; Zahran, A.H.; Kandeel, K.A.

    2000-01-01

    Particle boards based on different waste materials and different polymers as adhesives have been prepared by compression molding in a hot press at 120 degree and constant pressure. The used waste materials were cotton stalks, flax stalks and wood saw-dust whereas urea formaldehyde (UF), polystyrene (PS) and the epoxy resins 103 (E 103) and 150 (E 150) were used as adhesives. The thermally treated particleboard woods were subsequently exposed to gamma radiation. The static bending parameters of the different factors that may affect the mechanical properties such as irradiation dose, time of thermal treatment and adhesive content were also investigated. In general it was found that the highest mechanical properties of the unirradiated woods were obtained when the preparation was carried out under hot press for 20 min and the adhesive content was 20 wt.% (based on weight of waste material). The obtained results showed that the mechanical properties were greatly increased with increasing irradiation dose from 3 to 5 Mrad. Meanwhile, particleboard based on cotton or flax stalks and the epoxy resins 103 and 150 displayed higher mechanical properties than these based on wood saw-dust and the same adhesives

  10. Measurement of charged particle yields from PMMA irradiated by a 220 MeV/u12Cbeam

    CERN Document Server

    Piersanti, L; Bini, FU. Rome La Sapienza (main); Collamati, F; De Lucia, E; Durante, M; Faccini, R; Ferroni, F; Fiore, S; Iarocci, E; La Tessa, C; Marafini, M; Mattei, I; Patera, V; Ortega, P G; Sarti, A; Schuy, C; Sciubba, A; Vanstalle, M; Voena, C

    2014-01-01

    The radiation used in hadrontherapy treatments interacts with the patient body producing secondary particles, either neutral or charged, that can be used for dose and Bragg peak monitoring and to provide a fast feedback on the treatment plans. Recent results obtained from the authors on simplified setups (mono-energetic primary beams interacting with homogeneous tissue like target) have already indicated the correlation that exists between the flux of these secondaries coming from the target (e.g. protons and photons) and the position of the primary beam Bragg peak. In this paper, the measurements of charged particle fluxes produced by the interaction of a 220 MeV/u carbon ion beam at GSI, Darmstadt, with a polymethyl methacrylate target are reported. The emission region of protons (p), deuterons (d) and tritons (t) has been characterized using a drift chamber while the particle time-of-flight, used to compute the kinetic energy spectra, was measured with a LYSO scintillator.The energy released in the LYSO cr...

  11. Elaboration by ion implantation of cobalt nano-particles in silica layers and modifications of their properties by electron and swift heavy ion irradiations; Elaboration par implantation ionique de nanoparticules de cobalt dans la silice et modifications de leurs proprietes sous irradiation d'electrons et d'ions de haute energie

    Energy Technology Data Exchange (ETDEWEB)

    D' Orleans, C

    2003-07-15

    This work aims to investigate the capability of ion irradiations to elaborate magnetic nano-particles in silica layers, and to modify their properties. Co{sup +} ions have been implanted at 160 keV at fluences of 2.10{sup 16}, 5.10{sup 16} and 10{sup 17} at/cm{sup 2}, and at temperatures of 77, 295 and 873 K. The dependence of the particle size on the implantation fluence, and more significantly on the implantation temperature has been shown. TEM (transmission electronic microscopy) observations have shown a mean diameter varying from 1 nm for implantations at 2.10{sup 16} Co{sup +}/cm{sup 2} at 77 K, to 9.7 nm at 10{sup 17} Co{sup +}/cm{sup 2} at 873 K. For high temperature implantations, two regions of particles appear. Simulations based on a kinetic 3-dimensional lattice Monte Carlo method reproduce quantitatively the features observed for implantations. Thermal treatments induce the ripening of the particles. Electron irradiations at 873 K induce an important increase in mean particle sizes. Swift heavy ion irradiations also induce the ripening of the particles for low fluences, and an elongation of the particles in the incident beam direction for high fluences, resulting in a magnetic anisotropy. Mechanisms invoked in thermal spike model could also explain this anisotropic growth. (author)

  12. Elaboration by ion implantation of cobalt nano-particles in silica layers and modifications of their properties by electron and swift heavy ion irradiations; Elaboration par implantation ionique de nanoparticules de cobalt dans la silice et modifications de leurs proprietes sous irradiation d'electrons et d'ions de haute energie

    Energy Technology Data Exchange (ETDEWEB)

    D' Orleans, C

    2003-07-15

    This work aims to investigate the capability of ion irradiations to elaborate magnetic nano-particles in silica layers, and to modify their properties. Co{sup +} ions have been implanted at 160 keV at fluences of 2.10{sup 16}, 5.10{sup 16} and 10{sup 17} at/cm{sup 2}, and at temperatures of 77, 295 and 873 K. The dependence of the particle size on the implantation fluence, and more significantly on the implantation temperature has been shown. TEM (transmission electronic microscopy) observations have shown a mean diameter varying from 1 nm for implantations at 2.10{sup 16} Co{sup +}/cm{sup 2} at 77 K, to 9.7 nm at 10{sup 17} Co{sup +}/cm{sup 2} at 873 K. For high temperature implantations, two regions of particles appear. Simulations based on a kinetic 3-dimensional lattice Monte Carlo method reproduce quantitatively the features observed for implantations. Thermal treatments induce the ripening of the particles. Electron irradiations at 873 K induce an important increase in mean particle sizes. Swift heavy ion irradiations also induce the ripening of the particles for low fluences, and an elongation of the particles in the incident beam direction for high fluences, resulting in a magnetic anisotropy. Mechanisms invoked in thermal spike model could also explain this anisotropic growth. (author)

  13. Measurements of neutron spectrum from stopping-length target irradiated by several tens-MeV/u particles

    Energy Technology Data Exchange (ETDEWEB)

    Meigo, Shin-ichiro; Takada, Hiroshi; Nakashima, Hiroshi; Sasa, Toshinobu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Tanaka, Susumu; Shin, Kazuo; Ono, Shinji

    1997-03-01

    Using a Time-of-Flight technique, we have measured neutron spectra from stopping-length targets bombarded with 68-MeV protons and 100-MeV {alpha}-particles. The measured spectra were used to validate the results calculated by the Quantum Molecular Dynamics (QMD) plus Statistical Decay Model (SDM). The results of QMD plus SDM code agreed fairly well with the experimental data for the light target. On the other hand, the QMD plus SDM gives a larger value than the experimental for the heavy target. (author)

  14. Comparative study of Monte Carlo particle transport code PHITS and nuclear data processing code NJOY for PKA energy spectra and heating number under neutron irradiation

    International Nuclear Information System (INIS)

    Iwamoto, Y.; Ogawa, T.

    2016-01-01

    The modelling of the damage in materials irradiated by neutrons is needed for understanding the mechanism of radiation damage in fission and fusion reactor facilities. The molecular dynamics simulations of damage cascades with full atomic interactions require information about the energy distribution of the Primary Knock on Atoms (PKAs). The most common process to calculate PKA energy spectra under low-energy neutron irradiation is to use the nuclear data processing code NJOY2012. It calculates group-to-group recoil cross section matrices using nuclear data libraries in ENDF data format, which is energy and angular recoil distributions for many reactions. After the NJOY2012 process, SPKA6C is employed to produce PKA energy spectra combining recoil cross section matrices with an incident neutron energy spectrum. However, intercomparison with different processes and nuclear data libraries has not been studied yet. Especially, the higher energy (~5 MeV) of the incident neutrons, compared to fission, leads to many reaction channels, which produces a complex distribution of PKAs in energy and type. Recently, we have developed the event generator mode (EGM) in the Particle and Heavy Ion Transport code System PHITS for neutron incident reactions in the energy region below 20 MeV. The main feature of EGM is to produce PKA with keeping energy and momentum conservation in a reaction. It is used for event-by-event analysis in application fields such as soft error analysis in semiconductors, micro dosimetry in human body, and estimation of Displacement per Atoms (DPA) value in metals and so on. The purpose of this work is to specify differences of PKA spectra and heating number related with kerma between different calculation method using PHITS-EGM and NJOY2012+SPKA6C with different libraries TENDL-2015, ENDF/B-VII.1 and JENDL-4.0 for fusion relevant materials

  15. Reducing loss in lateral charged-particle equilibrium due to air cavities present in x-ray irradiated media by using longitudinal magnetic fields

    International Nuclear Information System (INIS)

    Naqvi, Shahid A.; Li, X. Allen; Ramahi, Shada W.; Chu, James C.; Ye, Sung-Joon

    2001-01-01

    The underdosing of lesions distal to air cavities, such as those found in upper respiratory passages, occurs due to the loss in lateral charged-particle equilibrium (CPE). The degree of underdosing worsens for smaller field sizes, resulting in more frequent recurrence of the cancer treated. Higher photon energies further aggravate the outcome by producing longer second build-up regions beyond the cavity. Besides underdosing, the larger lateral spread of secondary electron fluence in the air cavity produces diffuse dose distributions at the tissue-air interface for shaped or intensity modulated fields. These disequilibrium effects create undesirable deviations from the intended treatment. The clinical concern is further intensified by the failure of traditional treatment planning systems to even account for such defects. In this work, the use of longitudinal magnetic fields on the order of 0.5 T is proposed for alleviating lateral electronic disequilibrium due to the presence of air cavities in the irradiated volume. The magnetic field enforces lateral CPE by restricting the lateral range of electrons in the air cavity. The problem is studied in a simple water-air-water slab geometry using EGS4 Monte Carlo simulations for 6 MV photons. Electronic disequilibrium is evaluated for beams of various sizes, shapes and intensity distributions constructed by linear superposition of the dose distributions for 0.5x0.5 cm 2 beamlets. Comparison is also made with 60 Co irradiation. The results indicate that the lateral confinement of secondary electrons in the air cavity by sub-MRI strength longitudinal fields is effective in reducing deterioration of dose distributions near tissue-air interfaces. This can potentially reduce recurrence rates of cancers such as the larynx carcinoma

  16. Fission-product behaviour during irradiation of TRISO-coated particles in the HFREU1bis experiment - HTR2008-58125

    International Nuclear Information System (INIS)

    De Groot, S.; Bakker, K.; Barrachin, M.; Dubourg, R.; Kissane, M.

    2008-01-01

    The irradiation experiment HFR-EU1bis, coordinated by the European Joint Research Centre - Inst. for Energy, was performed in the High Flux Reactor (HFR) at Petten to test five spherical HTR fuel pebbles of former German production with TRISO coated particles in conditions beyond the specifications of current HTR reactor designs (central temperature of 1250 deg. C). In this paper, the behaviour of the fission products (FPs) and kernel micro-structure evolution during the test are investigated. While FP behaviour is a key issue for potential source term evaluation it also determines the evolution of the oxygen potential in the oxide kernel which in turn is important for formation of carbon oxides (amoeba effect and pressurization). Fission-gas release from the kernel can induce additional mechanical loading and finally some FPs (Ag, Cs, Sr) might alter the mechanical integrity of the coatings. This study is based on post- irradiation examinations (ceramography + EPMA) performed both on UO 2 kernels and on coatings. Significant evolutions of the kernel as a function of temperature are shown (grain structure, porosity, size of metallic inclusions). The quality of the ceramography results allows characteristics of the intergranular bubbles in the kernel (and estimation of swelling) to be determined. Remarkable results considering FP release from the kernel have been observed and will be presented. Examples are the significant release of Cs out of the kernel as well as Pd, whereas Zr remains trapped. Mo and Ru are mainly incorporated in metallic precipitates. These observations are interpreted and mechanisms for FP and micro-structural evolutions are proposed. These results are coupled to the results of calculations performed with the mechanistic code MFPR (Module for Fission Product Release) and the thermodynamic database MEPHISTA (Multiphase Equilibria in Fuels via Standard Thermodynamic Analysis). The effect of high flux rate and high temperature on fission gas

  17. Identification of biomarkers of radioresponse and subsequent progression towards lung cancer in normal human bronchial epithelial cells after HZE particle irradiation

    Science.gov (United States)

    Story, Michael; Ding, Liang-Hao; Park, Seongmi; Minna, John

    Using variants of a non-oncogenically immortalized human bronchial epithelial cell line HBEC3-KT, we have examined global gene expression patterns after low and high LET irradiation up to 24h post-IR. Using supervised analyses we have identified 427 genes whoes expression can be used to discriminate the cellular response to γ-vs Si or Fe particles even when the biological outcome, cell death, is equivalent. Furthermore, genetic background also determines gene expression response. When HBEC3-KT is compared to the HBEC3-KT cells line where mutant k-RAS is over-expressed and p53 has been knocked down, HBEC-3KTr53, principal component analysis clearly shows that the response of each cell resides in a different 3-D space, that is, basal gene expression patterns as well as the gene expression response are unique to each cell type. Using regression analysis to examine these 427 genes show clusters of genes whose temporal expression patterns are the same and which are unique to a given radiation type. Ultimately, this approach will allow for the interrogation of gene promoters to identify response elements that drive how cells respond to different radiation types. We are extending our examination to O particles and are now examining gene expression as a function of beam quality. We have made substantial progress in the determination of cellular transformation by HZE particles for these cell lines. (Transformation as defined by the ability to grow in soft agar.) For HBEC-3KT, the spontaneous transformation frequency is about 10- 7.ExposuretoeitherF eorSiparticlesinc KT r53celllinedidnotshowanyincreaseintransf ormationf requencyaf terdosesof upto1Gy, however, thesp 3KT.W ehavenowisolatedover160individualf ocithatf ormedinsof tagarf romcellculturesthatwereirradia termcultureandthenre-introducedintosof tagartoassurethattheabilitytogrowinsof tagarisclonal.T odatew 30 With these cell isolates in hand we will begin to determine tumorigenicity by subcutaneous injections in nude

  18. Effects of Low-Dose Alpha-Particle Irradiation in Human Cells: The Role of Induced Genes and the Bystander Effect. Final Technical Report (9/15/1998-5/31/2005)

    Energy Technology Data Exchange (ETDEWEB)

    Little, John B.

    2013-09-17

    This grant was designed to examine the cellular and molecular mechanisms for the bystander effect of radiation (initially described in this laboratory) whereby damage signals are passed from irradiated to non-irradiated cells in a population. These signals induce genetic effects including DNA damage, mutations and chromosomal aberrations in the nonirradiated cells. Experiments were carried out in cultured mammalian cells, primarily human diploid cells, irradiated with alpha particles. This research resulted in 17 publications in the refereed literature and is described in the Progress Report where it is keyed to the publication list. This project was initiated at the Harvard School of Public Health (HSPH) and continued in collaboration with students/fellows at Colorado State University (CSU) and the New Jersey Medical School (NJMS).

  19. On possibility of degradation of lava-like fuel-containing materials of the 4-th block of Chernobyl NPP under internal self-irradiation by alpha-particle sources

    International Nuclear Information System (INIS)

    Pazukhin, Eh. M.; Borovoj, A.A.; Rudya, K.G.

    2002-01-01

    It is shown that internal self-irradiation by alpha-particle beam cannot be a cause of change of strength characteristics of silicate matrix and so a cause of degradation of Chernobyl lava-like materials. A new method is proposed for management with lava-like fuel-containing materials of the 4-th block: vitrification in smelter unit situated in bubbler-basin and storage of prepared immobilized compacts in corresponding depositories [ru

  20. Efficiency of Cu2O/BiVO4 particles prepared with a new soft procedure on the degradation of dyes under visible-light irradiation

    International Nuclear Information System (INIS)

    Aguilera-Ruiz, Eduardo; García-Pérez, Ulises M.; Garza-Galván, María de la; Zambrano-Robledo, Patricia; Bermúdez-Reyes, Bárbara

    2015-01-01

    Graphical abstract: - Highlights: • Cu 2 O/BiVO 4 p–n heterojunctions were synthesized by a simple impregnation method. • The photocatalytic performance was evaluated using a LED lamp as visible source. • The composite with 1 wt.% of Cu 2 O exhibits the best visible-light-activity. • A mechanism for the carriers transfer is proposed. • Factors as pH and O 2 were found to influence the degradation rate. - Abstract: Cu 2 O/BiVO 4 composites with different concentrations of Cu 2 O were synthesized by a simple impregnation method at 200 °C under N 2 atmosphere for 4 h. The as-synthesized samples were characterized by X-ray powder diffraction, scanning electron microscopy, UV–vis diffuse reflection absorption and vis photoluminescence. The morphology of the as-synthesized composites with different weight ratios of Cu 2 O is composed by quasi-spherical and dendrite-like particles. The photocatalytic performance of the Cu 2 O/BiVO 4 composites was evaluated by degradation of methyl orange solutions under visible-LED irradiation. The results obtained show that the photocatalytic behavior of the p–n heterojunction Cu 2 O/BiVO 4 composites was better than pure Cu 2 O and BiVO 4 . The variation of the reaction parameters, such as solution pH and presence of O 2 , improved the photocatalytic performance of Cu 2 O/BiVO 4 composite. Meanwhile, a possible mechanism for methyl orange photocatalytic degradation over Cu 2 O/BiVO 4 photocatalysts was proposed. The chemical stability and reusability of Cu 2 O/BiVO 4 powders were also investigated

  1. Comparative study of Monte Carlo particle transport code PHITS and nuclear data processing code NJOY for recoil cross section spectra under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Iwamoto, Yosuke, E-mail: iwamoto.yosuke@jaea.go.jp; Ogawa, Tatsuhiko

    2017-04-01

    Because primary knock-on atoms (PKAs) create point defects and clusters in materials that are irradiated with neutrons, it is important to validate the calculations of recoil cross section spectra that are used to estimate radiation damage in materials. Here, the recoil cross section spectra of fission- and fusion-relevant materials were calculated using the Event Generator Mode (EGM) of the Particle and Heavy Ion Transport code System (PHITS) and also using the data processing code NJOY2012 with the nuclear data libraries TENDL2015, ENDF/BVII.1, and JEFF3.2. The heating number, which is the integral of the recoil cross section spectra, was also calculated using PHITS-EGM and compared with data extracted from the ACE files of TENDL2015, ENDF/BVII.1, and JENDL4.0. In general, only a small difference was found between the PKA spectra of PHITS + TENDL2015 and NJOY + TENDL2015. From analyzing the recoil cross section spectra extracted from the nuclear data libraries using NJOY2012, we found that the recoil cross section spectra were incorrect for {sup 72}Ge, {sup 75}As, {sup 89}Y, and {sup 109}Ag in the ENDF/B-VII.1 library, and for {sup 90}Zr and {sup 55}Mn in the JEFF3.2 library. From analyzing the heating number, we found that the data extracted from the ACE file of TENDL2015 for all nuclides were problematic in the neutron capture region because of incorrect data regarding the emitted gamma energy. However, PHITS + TENDL2015 can calculate PKA spectra and heating numbers correctly.

  2. Effect of different sulphur precursors on morphology and band-gap on the formation of Cu{sub 2}ZnSnS{sub 4} (CZTS) particles with microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Patro, Bharati; Vijaylakshmi, S., E-mail: vlakshmi@iitb.ac.in [Centre for Research in Nanotechnology and Sciences, Indian Institute of Technology Bombay (India); Sharma, Pratibha [Department of Energy Sciences and Engineering, Indian Institute of Technology Bombay (India)

    2016-05-23

    Cu{sub 2}ZnSnS{sub 4} (CZTS) is a promising semiconductor material for ecological cost effective thin film Photovoltaic (PV) devices. As it contains earth abundant and non-toxic elements, it has the advantages over commercially available CIGS and CdTe thin film PV devices. In the present work, the pure phase Cu{sub 2}ZnSnS{sub 4} particles were successfully synthesised with microwave irradiation. The morphology and phase study was carried out for the samples prepared with two different sulphur precursors viz. thiourea and thioacetamide (TAA). CZTS particles with thiourea as sulphur precursor are more crystalline than CZTS particles with TAA. The band gap of 1.654 eV and 1.713 eV were calculated for the samples prepared with thiourea and TAA respectively.

  3. Pigmented guinea pig skin irradiated with Q-switched ruby laser pulses. Morphologic and histologic findings

    Energy Technology Data Exchange (ETDEWEB)

    Dover, J.S.; Margolis, R.J.; Polla, L.L.; Watanabe, S.; Hruza, G.J.; Parrish, J.A.; Anderson, R.R.

    1989-01-01

    Q-switched ruby laser pulses cause selective damage to cutaneous pigmented cells. Repair of this selective damage has not been well described. Therefore, using epilated pigmented and albino guinea pig skin, we studied the acute injury and tissue repair caused by 40-ns, Q-switched ruby laser pulses. Gross observation and light and electron microscopy were performed. No specific changes were evident in the albino guinea pigs. In pigmented animals, with radiant exposures of 0.4 J/cm2 or greater, white spots confined to the 2.5-mm exposure sites developed immediately and faded over 20 minutes. Delayed depigmentation occurred at seven to ten days, followed by full repigmentation by four to eight weeks. Regrowing hairs in sites irradiated at and above 0.4 J/cm2 remained white for at least four months. Histologically, vacuolation of pigment-laden cells was seen immediately in the epidermis and the follicular epithelium at exposures of 0.3 J/cm2 and greater. Melanosomal disruption was seen immediately by electron microscopy at and above 0.3 J/cm2. Over the next seven days, epidermal necrosis was followed by regeneration of a depigmented epidermis. By four months, melanosomes and melanin pigmentation had returned; however, hair follicles remained depigmented and devoid of melanocytes. This study demonstrates that selective melanosomal disruption caused by Q-switched ruby laser pulses leads to transient cutaneous depigmentation and persistent follicular depigmentation. Potential exists for selective treatment of pigmented epidermal and dermal lesions with this modality.

  4. Treatment of cancer with heavy charged particles

    International Nuclear Information System (INIS)

    Castro, J.R.

    1981-01-01

    The clinical radiotherapy trial has accured 243 patients irradiated with particles and 13 patients irradiated as controls in randomized studies. Of the 243 particle patients, 194 have been treated with helium ions, either solely or in combination with photon irradiation, and 49 have received all or part of their irradiation with one of the heavier particles, either carbon, neon, or argon ions. The project thus can be divided into two general phases: (1) evaluation of improved dose distribution without significant biologic advantage by use of helium ion irradiation; and (2) evaluation of improved dose distribution and enhanced biologic effect by irradiation with heavy charged particles such as carbon, neon, and argon ions

  5. Industrial irradiation

    International Nuclear Information System (INIS)

    Stirling, Andrew

    1995-01-01

    Production lines for rubber gloves would not appear to have much in common with particle physics laboratories, but they both use accelerators. Electron beam irradiation is often used in industry to improve the quality of manufactured goods or to reduce production cost. Products range from computer disks, shrink packaging, tyres, cables, and plastics to hot water pipes. Some products, such as medical goods, cosmetics and certain foodstuffs, are sterilized in this way. In electron beam irradiation, electrons penetrate materials creating showers of low energy electrons. After many collisions these electrons have the correct energy to create chemically active sites. They may either break molecular bonds or activate a site which promotes a new chemical linkage. This industrial irradiation can be exploited in three ways: breaking down a biological molecule usually renders it useless and kills the organism; breaking an organic molecule can change its toxicity or function; and crosslinking a polymer can strengthen it. In addition to traditional gamma irradiation using isotopes, industrial irradiation uses three accelerator configurations, each type defining an energy range, and consequently the electron penetration depth. For energies up to 750 kV, the accelerator consists of a DC potential applied to a simple wire anode and the electrons extracted through a slot in a coaxially mounted cylindrical cathode. In the 1-5 MeV range, the Cockcroft-Walton or Dynamitron( R ) accelerators are normally used. To achieve the high potentials in these DC accelerators, insulating SF6 gas and large dimension vessels separate the anode and cathode; proprietary techniques distinguish the various commercial models available. Above 5 MeV, the size of DC accelerators render them impractical, and more compact radiofrequency-driven linear accelerators are used. Irradiation electron beams are actually 'sprayed' over the product using a magnetic deflection system. Lower energy beams of

  6. Simulation study of radial dose due to the irradiation of a swift heavy ion aiming to advance the treatment planning system for heavy particle cancer therapy: The effect of emission angles of secondary electrons

    Energy Technology Data Exchange (ETDEWEB)

    Moribayashi, Kengo, E-mail: moribayashi.kengo@jaea.go.jp

    2015-12-15

    A radial dose simulation model has been proposed in order to advance the treatment planning system for heavy particle cancer therapy. Here, the radial dose is the dose due to the irradiation of a heavy ion as a function of distances from this ion path. The model proposed here may overcome weak points of paradigms that are employed to produce the conventional radial dose distributions. To provide the radial dose with higher accuracy, this paper has discussed the relationship between the emission angles of secondary electrons and the radial dose. It is found that the effect of emission angles becomes stronger on the radial dose with increasing energies of the secondary electrons.

  7. Investigation of double strand breaks induced by alpha particle irradiation using C.N.B.G. microbeam in human keratinocytes; Mise en evidence de cassures double brin de l'ADN induites par irradiation de keratinocytes humains en microfaisceau alpha

    Energy Technology Data Exchange (ETDEWEB)

    Pouthier, Th

    2006-12-15

    To understand the mechanisms of interaction of ionizing radiation with living tissues exposed to low and protracted doses remains a major issue for risk evaluation. The response cannot be found in epidemiological studies because the only available data concern accidental exposures to high doses of radiation. The natural exposure represents the main source of exposure in the daily life, just before the medical sources (radiology, radiotherapy). In addition, this kind of exposure is very difficult to reproduce in vitro by irradiating cell lines. The method per preference is based on random irradiation of cell populations. The mean number of particles having traversed cells is then calculated on the basis of Poisson statistics. In addition to inevitable multiple impacts, the numerous potential intracellular targets (nuclei, cytoplasm), the indirect effects induced by the impact of particles on neighbouring cells or simply the extracellular targets, constitute phenomena that make more complex the interpretation of experimental data. A charged particle microbeam was developed at C.E.N.B.G. to perform the targeted irradiation of individual cells with a targeting precision of a few microns. It is possible to deliver a counted number of alpha particles down to the ultimate dose of one alpha per cell, to target predetermined cells and then to observe the response of the neighbouring cells. This facility has been validated during this work on human keratinocyte cells expressing a recombinant nuclear fluorescent protein (histone H2B-GFP). The combination of ion micro-beams with confocal microscopy and numeric quantitative analysis allowed the measurement of DNA double strand breaks via the phosphorylation of the histone H2A.X in individual cells. The mechanisms of DNA reparation and apoptosis induction were also in the scope of those studies. The experimental results obtained during this thesis validate the methodology we have developed by demonstrating the targeting

  8. Benefit of particle therapy in re-irradiation of head and neck patients. Results of a multicentric in silico ROCOCO trial

    NARCIS (Netherlands)

    Eekers, D.B.; Roelofs, E.; Jelen, U.; Kirk, M.; Granzier, M.; Ammazzalorso, F.; Ahn, P.H.; Janssens, G.O.; Hoebers, F.J.; Friedmann, T.; Solberg, T.; Walsh, S.; Troost, E.G.; Kaanders, J.H.A.M.; Lambin, P.

    2016-01-01

    BACKGROUND AND PURPOSE: In this multicentric in silico trial we compared photon, proton, and carbon-ion radiotherapy plans for re-irradiation of patients with squamous cell carcinoma of the head and neck (HNSCC) regarding dose to tumour and doses to surrounding organs at risk (OARs). MATERIAL AND

  9. Dependence of the annealing kinetics of A centers and divacancies on temperature, particle energy, and irradiation dose for n-Si crystals

    International Nuclear Information System (INIS)

    Pagava, T.A.

    2002-01-01

    n-Si crystals grown by the float-zone method with a phosphorus concentration of ∼6 x 10 13 cm -3 and irradiated with 2-MeV electrons and 25-MeV protons were studied. It is shown that the kinetics of the isochronous annealing of the A centers and divacancies (the annealing temperature and the rearrangement of radiation defects in the situation where the dissociation of one type of defects gives rise to more stable defects) depends in a complicated way on the energy, dose, and temperature of irradiation; i.e., this kinetics depends on the relation between the concentrations of various radiation defects and on the charge state of reacting primary radiation defects when they interact with each other, with impurity atoms, and with disordered regions. An increase in the concentration of divacancies in the temperature range of 180-210 deg. C is attributed to the dissociation of disordered regions

  10. The Lack of Cytotoxic Effect and Radioadaptive Response in Splenocytes of Mice Exposed to Low Level Internal β-Particle Irradiation through Tritiated Drinking Water in Vivo

    Directory of Open Access Journals (Sweden)

    Matthew Flegal

    2013-12-01

    Full Text Available Health effects of tritium, a β-emitter and a by-product of the nuclear industry, is a subject of significant controversy. This mouse in vivo study was undertaken to monitor biological effects of low level tritium exposure. Mice were exposed to tritiated drinking water (HTO at 10 KBq/L, 1 MBq/L and 20 MBq/L concentrations for one month. The treatment did not result in a significant increase of apoptosis in splenocytes. To examine if this low level tritium exposure alters radiosensitivity, the extracted splenocytes were challenged in vitro with 2 Gy γ-radiation, and apoptotic responses at 1 and 24 h were measured. No alterations in the radiosensitivity were detected in cells from mice exposed to tritium compared to sham-treated mice. In contrast, low dose γ-irradiation at 20 or 100 mGy, resulted in a significant increase in resistance to apoptotic cell death after 2 Gy irradiation; an indication of the radioadaptive response. Overall, our data suggest that low concentrations of tritium given to mice as HTO in drinking water do not exert cytotoxic effect in splenocytes, nor do they change cellular sensitivity to additional high dose γ-radiation. The latter may be considered as the lack of a radioadaptive response, typically observed after low dose γ-irradiation.

  11. Calculation simulation of equivalent irradiation swelling for dispersion nuclear fuel

    International Nuclear Information System (INIS)

    Cai Wei; Zhao Yunmei; Gong Xin; Ding Shurong; Huo Yongzhong

    2015-01-01

    The dispersion nuclear fuel was regarded as a kind of special particle composites. Assuming that the fuel particles are periodically distributed in the dispersion nuclear fuel meat, the finite element model to calculate its equivalent irradiation swelling was developed with the method of computational micro-mechanics. Considering irradiation swelling in the fuel particles and the irradiation hardening effect in the metal matrix, the stress update algorithms were established respectively for the fuel particles and metal matrix. The corresponding user subroutines were programmed, and the finite element simulation of equivalent irradiation swelling for the fuel meat was performed in Abaqus. The effects of the particle size and volume fraction on the equivalent irradiation swelling were investigated, and the fitting formula of equivalent irradiation swelling was obtained. The results indicate that the main factors to influence equivalent irradiation swelling of the fuel meat are the irradiation swelling and volume fraction of fuel particles. (authors)

  12. Food irradiation

    International Nuclear Information System (INIS)

    Soothill, R.

    1987-01-01

    The issue of food irradiation has become important in Australia and overseas. This article discusses the results of the Australian Consumers' Association's (ACA) Inquiry into food irradiation, commissioned by the Federal Government. Issues discussed include: what is food irradiation; why irradiate food; how much food is consumer rights; and national regulations

  13. Interaction of Al2O3xSiO2 alloyed uranium oxide with pyrocarbon coating of fuel particles under irradiation

    International Nuclear Information System (INIS)

    Chernikov, A.S.; Khromov, Yu.F.; Svistunov, D.E.; Chujko, E.E.

    1989-01-01

    Method of comparative data analysis for P O2 and P CO was used to consider interaction in fuel particle between pyrocarbon coating and fuel sample, alloyed with alumosilicate addition. Equations of interaction reactions for the case of hermetic and depressurized fuel particle are presented. Calculations of required xAl 2 O 3 XySiO 2 content, depending on oxide fuel burnup, were conducted. It was suggested to use silicon carbide for limitation of the upper level of CO pressure in fuel particle. Estimation of thermal stability of alumosilicates under conditions of uranium oxide burnup equals 1100 and 1500 deg C for Al/Si ratio in addition 1/1 and 4/1 respectively

  14. Food irradiation

    International Nuclear Information System (INIS)

    Lindqvist, H.

    1996-01-01

    This paper is a review of food irradiation and lists plants for food irradiation in the world. Possible applications for irradiation are discussed, and changes induced in food from radiation, nutritional as well as organoleptic, are reviewed. Possible toxicological risks with irradiated food and risks from alternative methods for treatment are also brought up. Ways to analyze weather food has been irradiated or not are presented. 8 refs

  15. Comparative study of energy of particles ejected from coulomb explosion of rare gas and metallic clusters irradiated by intense femtosecond laser field

    Science.gov (United States)

    Boucerredj, N.; Beggas, K.

    2016-10-01

    We present our study of high intensity femtosecond laser field interaction with large cluster of Kr and Na (contained 2.103 to 2.107 atoms). When laser intensity is above a critical value, it blows off all of electrons from the cluster and forms a non neutral ion cloud. The irradiation of these clusters by the intense laser field leads to highly excitation energy which can be the source of energetic electrons, electronic emission, highly charge, energetic ions and fragmentation process. During the Coulomb explosion of the resulting highly ionized, high temperature nanoplasma, ions acquire again their energy. It is shown that ultra fast ions are produced. The goal of our study is to investigate in detail a comparative study of the expansion and explosion then the ion energy of metallic and rare gas clusters irradiated by an intense femtosecond laser field. We have found that ions have a kinetic energy up to 105 eV and the Coulomb pressure is little than the hydrodynamic pressure. The Coulomb explosion of a cluster may provide a new high energy ion source.

  16. Food irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Gruenewald, T

    1985-01-01

    Food irradiation has become a matter of topical interest also in the Federal Republic of Germany following applications for exemptions concerning irradiation tests of spices. After risks to human health by irradiation doses up to a level sufficient for product pasteurization were excluded, irradiation now offers a method suitable primarily for the disinfestation of fruit and decontamination of frozen and dried food. Codex Alimentarius standards which refer also to supervision and dosimetry have been established; they should be adopted as national law. However, in the majority of cases where individual countries including EC member-countries so far permitted food irradiation, these standards were not yet used. Approved irradiation technique for industrial use is available. Several industrial food irradiation plants, partly working also on a contractual basis, are already in operation in various countries. Consumer response still is largely unknown; since irradiated food is labelled, consumption of irradiated food will be decided upon by consumers.

  17. Coordination of the Ser2056 and Thr2609 Clusters of DNA-PKcs in Regulating Gamma Rays and Extremely Low Fluencies of Alpha-Particle Irradiation to G0/G1 Phase Cells.

    Science.gov (United States)

    Nagasawa, Hatsumi; Lin, Yu-Fen; Kato, Takamitsu A; Brogan, John R; Shih, Hung-Ying; Kurimasa, Akihiro; Bedford, Joel S; Chen, Benjamin P C; Little, John B

    2017-02-01

    The catalytic subunit of DNA dependent protein kinase (DNA-PKcs) and its kinase activity are critical for mediation of non-homologous end-joining (NHEJ) of DNA double-strand breaks (DSB) in mammalian cells after gamma-ray irradiation. Additionally, DNA-PKcs phosphorylations at the T2609 cluster and the S2056 cluster also affect DSB repair and cellular sensitivity to gamma radiation. Previously we reported that phosphorylations within these two regions affect not only NHEJ but also homologous recombination repair (HRR) dependent DSB repair. In this study, we further examine phenotypic effects on cells bearing various combinations of mutations within either or both regions. Effects studied included cell killing as well as chromosomal aberration induction after 0.5-8 Gy gamma-ray irradiation delivered to synchronized cells during the G 0 /G 1 phase of the cell cycle. Blocking phosphorylation within the T2609 cluster was most critical regarding sensitization and depended on the number of available phosphorylation sites. It was also especially interesting that only one substitution of alanine in each of the two clusters separately abolished the restoration of wild-type sensitivity by DNA-PKcs. Similar patterns were seen for induction of chromosomal aberrations, reflecting their connection to cell killing. To study possible change in coordination between HRR and NHEJ directed repair in these DNA-PKcs mutant cell lines, we compared the induction of sister chromatid exchanges (SCEs) by very low fluencies of alpha particles with mutant cells defective in the HRR pathway that is required for induction of SCEs. Levels of true SCEs induced by very low fluence of alpha-particle irradiation normally seen in wild-type cells were only slightly decreased in the S2056 cluster mutants, but were completely abolished in the T2609 cluster mutants and were indistinguishable from levels seen in HRR deficient cells. Again, a single substitution in the S2056 together with a single

  18. Experimental Set-up for Irradiation of Solid H2 and D2 with Charged Particles of keV Energies

    DEFF Research Database (Denmark)

    Sørensen, H.

    1976-01-01

    crystal film thickness monitor. The target plate, which can be heated so that films are removable by evaporation, may be used both as a calorimeter and as a beam current collector. Methods for measurement of secondary electron emission coefficients were developed, and preliminary measurements were made...... with electrons and hydrogen ions. For electron bombardment, the secondary electron emission coefficient of solid deuterium was much smaller than one. It was shown possible to use the set-up to study beam desorption of very thin films. Furthermore the set-up could be used for measuring the energy......An experimental facility was built where films of solid deuterium (and hydrogen) may be made with known thickness and irradiated with pulsed beams of electrons (up to 3 keV) and light ions (up to 10 keV). Films are made on a target plate held at 2.5–3 K. Film growth rate is calibrated with a quartz...

  19. Thermoluminescent dependence with the particle size of polyminerals in food irradiated of Mexican spices; Dependencia Tl con el tamano de particula de poliminerales en alimentos irradiados de especias Mexicanas

    Energy Technology Data Exchange (ETDEWEB)

    Teuffer Z, C. [FQ-UNAM, 04510 Mexico D.F. (Mexico); Cruz Z, E. [ICN-UNAM, A.P. 70-543, 04510 Mexico D.F. (Mexico); Calderon, T. [Depto. de Quimica Agricola-Geologia- Geoquimica, Universidad Autonoma de Madrid, 28049 (Spain); Chernov, V.; Barboza F, M. [CIF, UNISON, A.P. 5-88, Hermosillo, Sonora (Mexico)

    2004-07-01

    The influence of grain size on Tl was analysed in poly minerals extracted from Mexican spices as Origanum vulgare L. (oregano) y Capsicum annun (chile guajillo). The poly minerals size were selected by Zimmerman method up to 10 {mu}m and exposed to 0.5-10 kGy range from {sup 60}Co. The glow curves were centered at 166 C for Capsicum annun and at 126 C for Origanum vulgare l. In both cases was observed at 5 kGy a weak saturation for Tl response. This behaviour is attributed to feldspar and quartz are present in the samples and this results is in agreement with other european spices obtained. For >10 {mu}m particle size the Tl response increased respect to the doses, and it is possible that increase the organic impurities quantities are present in the samples and contributed to the Tl when the samples were thermally excited. The aim of this work is provide more ideas with regard to the behaviour of luminescence emission as dependent of the size particle in the irradiated spices. The methodology might useful for quality control also in radiation processing. (Author)

  20. Food irradiation

    International Nuclear Information System (INIS)

    Sato, Tomotaro; Aoki, Shohei

    1976-01-01

    Definition and significance of food irradiation were described. The details of its development and present state were also described. The effect of the irradiation on Irish potatoes, onions, wiener sausages, kamaboko (boiled fish-paste), and mandarin oranges was evaluated; and healthiness of food irradiation was discussed. Studies of the irradiation equipment for Irish potatoes in a large-sized container, and the silo-typed irradiation equipment for rice and wheat were mentioned. Shihoro RI center in Hokkaido which was put to practical use for the irradiation of Irish potatoes was introduced. The state of permission of food irradiation in foreign countries in 1975 was introduced. As a view of the food irradiation in the future, its utilization for the prevention of epidemics due to imported foods was mentioned. (Serizawa, K.)

  1. Gamma irradiator

    International Nuclear Information System (INIS)

    Simonet, G.

    1986-09-01

    Fiability of devices set around reactors depends on material resistance under irradiation noticeably joints, insulators, which belongs to composition of technical, safety or physical incasurement devices. The irradiated fuel elements, during their desactivation in a pool, are an interesting gamma irradiation device to simulate damages created in a nuclear environment. The existing facility at Osiris allows to generate an homogeneous rate dose in an important volume. The control of the element distances to irradiation box allows to control this dose rate [fr

  2. Food irradiation

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    The article explains what radiation does to food to preserve it. Food irradiation is of economic importance to Canada because Atomic Energy of Canada Limited is the leading world supplier of industrial irradiators. Progress is being made towards changing regulations which have restricted the irradiation of food in the United States and Canada. Examples are given of applications in other countries. Opposition to food irradiation by antinuclear groups is addressed

  3. Food irradiation

    International Nuclear Information System (INIS)

    Beyers, M.

    1977-01-01

    The objectives of food irradiation are outlined. The interaction of irradiation with matter is then discussed with special reference to the major constituents of foods. The application of chemical analysis in the evaluation of the wholesomeness of irradiated foods is summarized [af

  4. Microstructure of irradiated materials

    International Nuclear Information System (INIS)

    Robertson, I.M.

    1995-01-01

    The focus of the symposium was on the changes produced in the microstructure of metals, ceramics, and semiconductors by irradiation with energetic particles. the symposium brought together those working in the different material systems, which revealed that there are a remarkable number of similarities in the irradiation-produced microstructures in the different classes of materials. Experimental, computational and theoretical contributions were intermixed in all of the sessions. This provided an opportunity for these groups, which should interact, to do so. Separate abstracts were prepared for 58 papers in this book

  5. Food irradiation

    International Nuclear Information System (INIS)

    Macklin, M.

    1987-01-01

    The Queensland Government has given its support the establishment of a food irradiation plant in Queensland. The decision to press ahead with a food irradiation plant is astonishing given that there are two independent inquiries being carried out into food irradiation - a Parliamentary Committee inquiry and an inquiry by the Australian Consumers Association, both of which have still to table their Reports. It is fair to assume from the Queensland Government's response to date, therefore, that the Government will proceed with its food irradiation proposals regardless of the outcomes of the various federal inquiries. The reasons for the Australian Democrats' opposition to food irradiation which are also those of concerned citizens are outlined

  6. Food irradiation

    International Nuclear Information System (INIS)

    Duchacek, V.

    1989-01-01

    The ranges of doses used for food irradiation and their effect on the processed foods are outlined. The wholesomeness of irradiated foods is discussed. The present food irradiation technology development in the world is described. A review of the irradiated foods permitted for public consumption, the purposes of food irradiaton, the doses used and a review of the commercial-scale food irradiators are tabulated. The history and the present state of food processing in Czechoslovakia are described. (author). 1 fig., 3 tabs., 13 refs

  7. Irradiated foods

    International Nuclear Information System (INIS)

    Darrington, Hugh

    1988-06-01

    This special edition of 'Food Manufacture' presents papers on the following aspects of the use of irradiation in the food industry:- 1) an outline view of current technology and its potential. 2) Safety and wholesomeness of irradiated and non-irradiated foods. 3) A review of the known effects of irradiation on packaging. 4) The problems of regulating the use of irradiation and consumer protection against abuse. 5) The detection problem - current procedures. 6) Description of the Gammaster BV plant in Holland. 7) World outline review. 8) Current and future commercial activities in Europe. (U.K.)

  8. Contribution to the study of defects created by {alpha} particles in uranium at 4.2 K; Contribution a l'etude des defauts crees par irradiation a l'aide de particules {alpha} dans l'uranium a 4.2 K

    Energy Technology Data Exchange (ETDEWEB)

    Raharinaivo, A.L. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1969-07-01

    A device is described for the irradiation, in liquid helium, of metallic strips with {alpha} particles produced by radioactive sources. It has thereby been possible to measure changes in resistivity of variously treated uranium samples (cold- worked, annealed, previously exposed to neutrons, etc. ) as a function of the irradiation flux. The annealings carried out after irradiation compare favorably to those effected after a quenching from 100 to 4 K (JOUSSET experiments). The results are discussed; it is concluded that a defect, very probably of the interstitial type, is mobile in uranium at temperatures below 5 K. (author) [French] On decrit un dispositif permettant d'irradier, dans l'helium liquide, des lames metalliques par des particules {alpha} issues de sources radioactives. On a ainsi mesure les variations de resistivite, en fonction du flux d'irradiation, d'uranium diversement traite (ecroui, recuit, prealablement irradie par des neutrons...). Les recuits apres irradiation se comparent bien aux recuits apres trempe de 100 a 4 K (experiences de JOUSSET). L'ensemble des resultats est discute et il conduit a la conclusion qu'un defaut, tres vraisemblablement interstitiel, est mobile dans l'uranium a des temperatures inferieures a 5 K. (auteur)

  9. Contribution to the study of defects created by {alpha} particles in uranium at 4.2 K; Contribution a l'etude des defauts crees par irradiation a l'aide de particules {alpha} dans l'uranium a 4.2 K

    Energy Technology Data Exchange (ETDEWEB)

    Raharinaivo, A L [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1969-07-01

    A device is described for the irradiation, in liquid helium, of metallic strips with {alpha} particles produced by radioactive sources. It has thereby been possible to measure changes in resistivity of variously treated uranium samples (cold- worked, annealed, previously exposed to neutrons, etc. ) as a function of the irradiation flux. The annealings carried out after irradiation compare favorably to those effected after a quenching from 100 to 4 K (JOUSSET experiments). The results are discussed; it is concluded that a defect, very probably of the interstitial type, is mobile in uranium at temperatures below 5 K. (author) [French] On decrit un dispositif permettant d'irradier, dans l'helium liquide, des lames metalliques par des particules {alpha} issues de sources radioactives. On a ainsi mesure les variations de resistivite, en fonction du flux d'irradiation, d'uranium diversement traite (ecroui, recuit, prealablement irradie par des neutrons...). Les recuits apres irradiation se comparent bien aux recuits apres trempe de 100 a 4 K (experiences de JOUSSET). L'ensemble des resultats est discute et il conduit a la conclusion qu'un defaut, tres vraisemblablement interstitiel, est mobile dans l'uranium a des temperatures inferieures a 5 K. (auteur)

  10. ELECTRON PROBE MICROANALYSIS OF IRRADIATED AND 1600°C SAFETY-TESTED AGR-1 TRISO FUEL PARTICLES WITH LOW AND HIGH RETAINED 110MAG

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Karen E.; van Rooyen, Isabella J.

    2016-11-01

    AGR-1 fuel Compact 4-3-3 achieved 18.63% FIMA and was exposed subsequently to a safety test at 1600°C. Two particles, AGR1-433-003 and AGR1-433-007, with measured-to-calculated 110mAg inventories of <22% and 100%, respectively, were selected for comparative electron microprobe analysis to determine whether the distribution or abundance of fission products differed proximally and distally from the deformed kernel in AGR1-433-003, and how this compared to fission product distribution in AGR1-433-007. On the deformed side of AGR1-433-003, Xe, Cs, I, Eu, Sr, and Te concentrations in the kernel buffer interface near the protruded kernel were up to six times higher than on the opposite, non-deformed side. At the SiC-inner pyrolytic carbon (IPyC) interface proximal to the deformed kernel, Pd and Ag concentrations were 1.2 wt% and 0.04 wt% respectively, whereas on the SiC-IPyC interface distal from the kernel deformation those elements measured 0.4 and 0.01 wt%, respectively. Palladium and Ag concentrations at the SiC-IPyC interface of AGR1-433-007 were 2.05 and 0.05 wt.%, respectively. Rare earth element concentrations at the SiC-IPyC interface of AGR1-433-007 were a factor of ten higher than at the SiC-IPyC interfaces measured in particle AGR1-433-003. Palladium permeated the SiC layer of AGR1-433-007 and the non-deformed SiC layer of AGR1-433-003.

  11. Charge transport in non-irradiated and irradiated silicon detectors

    International Nuclear Information System (INIS)

    Leroy, C.; Roy, P.; Casse, G.L.; Glaser, M.; Grigoriev, E.; Lemeilleur, F.

    1999-01-01

    A model describing the transport of the charge carriers generated in n-type silicon detectors by ionizing particles is presented. In order to reproduce the experimental current pulse responses induced by α and β particles in non-irradiated and irradiated detectors up to fluences (PHI) much beyond the n to p-type inversion, an n-type region 15 μm deep is introduced on the p + side of the diode. This model also gives mobilities which decrease linearly up to fluences of around 5x10 13 particles/cm 2 and beyond, converging to saturation values of about 1000 and 450 cm 2 /V s for electrons and holes, respectively. The charge carrier lifetime degradation with increased fluence, due to trapping, is responsible for a predicted charge collection deficit for β particles and for α particles which is found to agree with direct CCE measurements. (author)

  12. Low-enriched fuel particle performance review

    International Nuclear Information System (INIS)

    Homan, F.; Nabielek, H.; Yang, L.

    1978-08-01

    The available data on low-enriched (LEU) fuel particles were reviewed under the United States-Federal Republic of Germany Agreement. The most influential factors controlling the irradiation performance of LEU fuel particles were found to be plutonium transport, fission product transport, fuel particle mechanical performance and fuel particle chemical performande. (orig.) [de

  13. Low-enriched fuel particle performance review

    International Nuclear Information System (INIS)

    Homan, F.; Nabielek, H.; Yang, L.

    1978-08-01

    The available data on low-enriched uranium (LEU) fuel particles were reviewed under the United States-Federal Republic of Germany Agreement. The most influential factors controlling the irradiation performance of LEU fuel particles were found to be plutonium transport, fission product transport, fuel particle mechanical performance, and fuel particle chemical performance

  14. Microdosimetry of haemopoietic stem cells irradiated by α particles from the short-lived products of 222Rn decays in fat cells and haemopoietic tissue

    International Nuclear Information System (INIS)

    Charlton, D.E.; Utteridge, T.D.; University of South Australia, Pooraka, SA; Beddoe, A.H.

    1996-01-01

    The Monte Carlo method is used to model fat cells and the nuclei of stem cells in haemopoietic tissue where 222 Rn is dissolved in different amounts in the fat and tissue. Calculations are performed for fat cells of diameters 50 and 100 μm and for stem cell nuclei of 8 and 16 μm diameters for various fractions of fat filling the volume. Average doses (and their distributions) to stem cell nuclei from single passages of α particles are presented. In addition to dose, the relationship between LET and dose is obtained, illustrating the importance of 'stoppers' in the calculations. The annual average dose equivalent for a concentration of 1 Bq/m 3 in air agrees well with other authors at 12 μSv/year. The method also allows the calculation of the fraction of stem cell nuclei hit annually. Here for 1 Bq/m 3 , stem cell nuclei of diameter 8 μm and 100% fat filing 15 x 10 -7 of the stem cell nuclei are hit. (Author)

  15. Particle Pollution

    Science.gov (United States)

    ... Your Health Particle Pollution Public Health Issues Particle Pollution Recommend on Facebook Tweet Share Compartir Particle pollution — ... see them in the air. Where does particle pollution come from? Particle pollution can come from two ...

  16. Foodstuff irradiation

    International Nuclear Information System (INIS)

    1982-01-01

    Report written on behalf of the Danish Food Institute summarizes national and international rules and developments within food irradiation technology, chemical changes in irradiated foodstuffs, microbiological and health-related aspects of irradiation and finally technological prospects of this conservation form. Food irradiatin has not been hitherto applied in Denmark. Radiation sources and secondary radiation doses in processed food are characterized. Chemical changes due to irradiation are compared to those due to p.ex. food heating. Toxicological and microbiological tests and their results give no unequivocal answer to the problem whether a foodstuff has been irradiated. The most likely application fields in Denmark are for low radiation dosis inhibition of germination, riping delay and insecticide. Medium dosis (1-10 kGy) can reduce bacteria number while high dosis (10-50 kGy) will enable total elimination of microorganisms and viruses. Food irradiation can be acceptable as technological possibility with reservation, that further studies follow. (EG)

  17. Studies on the irradiated solids

    International Nuclear Information System (INIS)

    Lesueur, D.

    1988-01-01

    The 1988 progress report of the Irradiated Solids laboratory (Polytechnic School, France), is presented. The Laboratory activities concern the investigations on disordered solids (chemical or structural disorder). The disorder itself, its effects on the material physical properties and the particle-matter interactions, are investigated. The research works are performed in the following fields: solid state physics, irradiation and stoechiometric defects, and nuclear materials. The scientific reviews, the congress communications and the thesis are listed [fr

  18. Hemibody irradiation

    International Nuclear Information System (INIS)

    Schen, B.C.; Mella, O.; Dahl, O.

    1992-01-01

    In a large number of cancer patients, extensive skeletal metastases or myelomatosis induce vast suffering, such as intolerable pain and local complications of neoplastic bone destruction. Analgetic drugs frequently do not yield sufficient palliation. Irradiation of local fields often has to be repeated, because of tumour growth outside previously irradiated volumes. Wide field irradiation of the lower or upper half of the body causes significant relief of pain in most patients. Adequate pretreatment handling of patients, method of irradiation, and follow-up are of importance to reduce side effects, and are described as they are carried out at the Department of Oncology, Haukeland Hospital, Norway. 16 refs., 2 figs

  19. Mechanical properties of irradiated beryllium

    International Nuclear Information System (INIS)

    Beeston, J.M.; Longhurst, G.R.; Wallace, R.S.

    1992-01-01

    Beryllium is planned for use as a neutron multiplier in the tritium breeding blanket of the International Thermonuclear Experimental Reactor (ITER). After fabricating samples of beryllium at densities varying from 80 to 100% of the theoretical density, we conducted a series of experiments to measure the effect of neutron irradiation on mechanical properties, especially strength and ductility. Samples were irradiated in the Advanced Test Reactor (ATR) to a neutron fluence of 2.6 x 10 25 n/m 2 (E > MeV) at an irradiation temperature of 75deg C. These samples were subsequently compression-tested at room temperature, and the results were compared with similar tests on unirradiated specimens. We found that the irradiation increased the strength by approximately four times and reduced the ductility to approximately one fourth. Failure was generally ductile, but the 80% dense irradiated samples failed in brittle fracture with significant generation of fine particles and release of small quantities of tritium. (orig.)

  20. Mechanical properties of irradiated beryllium

    Science.gov (United States)

    Beeston, J. M.; Longhurst, G. R.; Wallace, R. S.; Abeln, S. P.

    1992-10-01

    Beryllium is planned for use as a neutron multiplier in the tritium breeding blanket of the International Thermonuclear Experimental Reactor (ITER). After fabricating samples of beryllium at densities varying from 80 to 100% of the theoretical density, we conducted a series of experiments to measure the effect of neutron irradiation on mechanical properties, especially strength and ductility. Samples were irradiated in the Advanced Test Reactor (ATR) to a neutron fluence of 2.6 × 10 25 n/m 2 ( E > 1 MeV) at an irradiation temperature of 75°C. These samples were subsequently compression-tested at room temperature, and the results were compared with similar tests on unirradiated specimens. We found that the irradiation increased the strength by approximately four times and reduced the ductility to approximately one fourth. Failure was generally ductile, but the 80% dense irradiated samples failed in brittle fracture with significant generation of fine particles and release of small quantities of tritium.

  1. Positive ion irradiation facility

    International Nuclear Information System (INIS)

    Braby, L.A.

    1985-01-01

    Many questions about the mechanisms of the response of cells to ionizing radiation can best be investigated using monoenergetic heavy charged particle beams. Questions of the role of different types of damage in the LET effect, for example, are being answered by comparing repair kinetics for damage induced by electrons with that produced by helium ions. However, as the models become more sophicated, the differences between models can be detected only with more precise measurements, or by combining high- and low-LET irradiations in split-dose experiments. The design of the authors present cell irradiation beam line has limited the authors to irradiating cells in a partial vacuum. A new way to mount the dishes and bring the beam to the cells was required. Several means of irradiating cells in mylar-bottom dishes have been used at other laboratories. For example at the RARAF Facility, the dual ion experiments are done with the dish bottom serving as the beam exit window but the cells are in a partial vacuum to prevent breaking the window. These researchers have chosen instead to use the dish bottom as the beam window and to irradiate the entire dish in a single exposure. A special, very fast pumping system will be installed at the end of the beam line. This system will make it possible to irradiate cells within two minutes of installing them in the irradiation chamber. In this way, the interaction of electron and ion-induced damage in Chlamydomonas can be studied with time between doses as short as 5 minutes

  2. Nuclear prehistory influence on irradiated metallic iron phase composition

    International Nuclear Information System (INIS)

    Alekseev, I.E.

    2007-01-01

    With application of different Moessbauer spectroscopy applications the phase composition of metallic iron after irradiation by both neutrons and charged particles were studied. Irradiation conditions, method of targets examination and phase composition of samples after irradiation were presented in tabular form. It is shown, that phase composition of irradiated metal is defined by nuclear prehistory. So, in a number of cases abnormals (stabilization of high- and low-temperature structural phases of iron at room temperature after irradiation end) were revealed

  3. Food irradiation

    International Nuclear Information System (INIS)

    Mercader, J.P.; Emily Leong

    1985-01-01

    The paper discusses the need for effective and efficient technologies in improving the food handling system. It defines the basic premises for the development of food handling. The application of food irradiation technology is briefly discussed. The paper points out key considerations for the adoption of food irradiation technology in the ASEAN region (author)

  4. Food irradiation

    International Nuclear Information System (INIS)

    Matsuyama, Akira

    1990-01-01

    This paper reviews researches, commentaries, and conference and public records of food irradiation, published mainly during the period 1987-1989, focusing on the current conditions of food irradiation that may pose not only scientific or technologic problems but also political issues or consumerism. Approximately 50 kinds of food, although not enough to fill economic benefit, are now permitted for food irradiation in the world. Consumerism is pointed out as the major factor that precludes the feasibility of food irradiation in the world. In the United States, irradiation is feasible only for spices. Food irradiation has already been feasible in France, Hollands, Belgium, and the Soviet Union; has under consideration in the Great Britain, and has been rejected in the West Germany. Although the feasibility of food irradiation is projected to increase gradually in the future, commercial success or failure depends on the final selection of consumers. In this respect, the role of education and public information are stressed. Meat radicidation and recent progress in the method for detecting irradiated food are referred to. (N.K.) 128 refs

  5. Irradiation proctitis

    International Nuclear Information System (INIS)

    Minami, Akira

    1977-01-01

    Literatures on late rectal injuries are discussed, referring to two patients with uterine cervical cancer in whom irradiation proctitis occurred after telecobalt irradiation following uterine extirpation. To one patients, a total of 5000 rads was irradiated, dividing into 250 rads at one time, and after 3 months, irradiation with a total of 2000 rads, dividing into 200 rads at one time, was further given. In another one patient, two parallel opposing portal irradiation with a total of 6000 rads was given. About a year after the irradiation, rectal injuries and cystitis, accompanying with hemorrhage, were found in both of the patients. Rectal amputation and proctotoreusis were performed. Cystitis was treated by cystic irradiation in the urological department. Pathohistological studies of the rectal specimen revealed atrophic mucosa, and dilatation of the blood vessels and edema in the colonic submucosa. Incidence of this disease, term when the disease occurs, irradiation dose, type of the disease, treatment and prevention are described on the basis of the literatures. (Kanao, N.)

  6. Irradiation proctitis

    Energy Technology Data Exchange (ETDEWEB)

    Minami, A [Osaka Kita Tsishin Hospital (Japan)

    1977-06-01

    Literatures on late rectal injuries are discussed, referring to two patients with uterine cervical cancer in whom irradiation proctitis occurred after telecobalt irradiation following uterine extirpation. To one patients, a total of 5000 rads was irradiated, dividing into 250 rads at one time, and after 3 months, irradiation with a total of 2000 rads, dividing into 200 rads at one time, was further given. In another one patient, two parallel opposing portal irradiation with a total of 6000 rads was given. About a year after the irradiation, rectal injuries and cystitis, accompanying with hemorrhage, were found in both of the patients. Rectal amputation and proctotoreusis were performed. Cystitis was treated by cystic irradiation in the urological department. Pathohistological studies of the rectal specimen revealed atrophic mucosa, and dilatation of the blood vessels and edema in the colonic submucosa. Incidence of this disease, term when the disease occurs, irradiation dose, type of the disease, treatment and prevention are described on the basis of the literatures.

  7. Food irradiation

    International Nuclear Information System (INIS)

    Kobayashi, Yasuhiko; Kikuchi, Masahiro

    2009-01-01

    Food irradiation can have a number of beneficial effects, including prevention of sprouting; control of insects, parasites, pathogenic and spoilage bacteria, moulds and yeasts; and sterilization, which enables commodities to be stored for long periods. It is most unlikely that all these potential applications will prove commercially acceptable; the extend to which such acceptance is eventually achieved will be determined by practical and economic considerations. A review of the available scientific literature indicates that food irradiation is a thoroughly tested food technology. Safety studies have so far shown no deleterious effects. Irradiation will help to ensure a safer and more plentiful food supply by extending shelf-life and by inactivating pests and pathogens. As long as requirement for good manufacturing practice are implemented, food irradiation is safe and effective. Possible risks of food irradiation are not basically different from those resulting from misuse of other processing methods, such as canning, freezing and pasteurization. (author)

  8. Irradiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Howe, L.M

    2000-07-01

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

  9. Irradiation damage

    International Nuclear Information System (INIS)

    Howe, L.M.

    2000-01-01

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

  10. AGR-1 Post Irradiation Examination Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Demkowicz, Paul Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-08-01

    The post-irradiation examination (PIE) of the Advanced Gas Reactor (AGR)-1 experiment was a multi-year, collaborative effort between Idaho National Laboratory (INL) and Oak Ridge National Laboratory (ORNL) to study the performance of UCO (uranium carbide, uranium oxide) tristructural isotropic (TRISO) coated particle fuel fabricated in the U.S. and irradiated at the Advanced Test Reactor at INL to a peak burnup of 19.6% fissions per initial metal atom. This work involved a broad array of experiments and analyses to evaluate the level of fission product retention by the fuel particles and compacts (both during irradiation and during post-irradiation heating tests to simulate reactor accident conditions), investigate the kernel and coating layer morphology evolution and the causes of coating failure, and explore the migration of fission products through the coating layers. The results have generally confirmed the excellent performance of the AGR-1 fuel, first indicated during the irradiation by the observation of zero TRISO coated particle failures out of 298,000 particles in the experiment. Overall release of fission products was determined by PIE to have been relatively low during the irradiation. A significant finding was the extremely low levels of cesium released through intact coatings. This was true both during the irradiation and during post-irradiation heating tests to temperatures as high as 1800°C. Post-irradiation safety test fuel performance was generally excellent. Silver release from the particles and compacts during irradiation was often very high. Extensive microanalysis of fuel particles was performed after irradiation and after high-temperature safety testing. The results of particle microanalysis indicate that the UCO fuel is effective at controlling the oxygen partial pressure within the particle and limiting kernel migration. Post-irradiation examination has provided the final body of data that speaks to the quality of the AGR-1 fuel, building

  11. Formation of amorphous layers by irradiation

    International Nuclear Information System (INIS)

    Bourgoin, J.C.

    1979-01-01

    When an ordered solid is irradiated with heavy energy particles, disorder is produced. When the irradiation dose exceeds a so-called critical dose, the irradiated area of the solid becomes uniformly disordered. Mention is first made of the nature, concentration and distribution of the defects created by a heavy energy particle. The description is then given -solely with respect to semiconductors- of the effect of the various parameters on the critical dose energy and nature of the ion, nature and temperature of the solid, irradiation flux. The physical properties (electronic and thermodynamic types) and the uniformly disordered areas are briefly discussed and these properties are compared with those of amorphous semiconductor layers fabricated by evaporation. It is concluded that the evaporated and irradiated layers are similar in nature. It is suggested that the transformation of an irradiated crystalline area into an amorphous one occurs when the Gibbs energy of the crystal become greater than the Gibbs energy of the amorphous one [fr

  12. HRB-22 capsule irradiation test for HTGR fuel. JAERI/USDOE collaborative irradiation test

    Energy Technology Data Exchange (ETDEWEB)

    Minato, Kazuo; Sawa, Kazuhiro; Fukuda, Kousaku [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; and others

    1998-03-01

    As a JAERI/USDOE collaborative irradiation test for high-temperature gas-cooled reactor fuel, JAERI fuel compacts were irradiated in the HRB-22 irradiation capsule in the High Flux Isotope Reactor at the Oak Ridge National Laboratory (ORNL). Postirradiation examinations also were performed at ORNL. This report describes 1) the preirradiation characterization of the irradiation samples of annular-shaped fuel compacts containing the Triso-coated fuel particles, 2) the irradiation conditions and fission gas releases during the irradiation to measure the performance of the coated particle fuel, 3) the postirradiation examinations of the disassembled capsule involving visual inspection, metrology, ceramography and gamma-ray spectrometry of the samples, and 4) the accident condition tests on the irradiated fuels at 1600 to 1800degC to obtain information about fuel performance and fission product release behavior under accident conditions. (author)

  13. Influence of irradiation with energy-rich particles on the hardness of the Fe-Cr alloy; Einfluss der Bestrahlung mit energiereichen Teilchen auf die Haerte von Fe-Cr-Legierungen

    Energy Technology Data Exchange (ETDEWEB)

    Heintze, Cornelia

    2013-01-14

    Ferritic/martensitic and oxide dispersion strengthened ferritic/martensitic steels are candidate structural materials for components exposed to high neutron fluxes in future nuclear applications like fusion and generation IV fission reactors. The ductilebrittle transition and its shift to higher temperatures which is predominantly caused by irradiation hardening are main concerns for these materials. In the present work, the irradiation behaviour of binary Fe-Cr model alloys, which represent a simplified model for ferritic/martensitic steels, is studied. To this end irradiation with iron ions is used in order to simulate the neutron-induced damage. Due to the limited penetration depth characterization methods suitable for thin layers have to be applied. In the present case, nanohardness testing and transmission electron microscopy (TEM) are employed. The results, including the irradiation-induced hardness change of the layer as a function of chromium content, fluence and irradiation temperature and, for selected cases, quantitative TEM analyses, were exploited to identify irradiation-induced dislocation loops as one source of irradiation hardening. Additional results of small-angle neutron scattering experiments on neutron-irradiated specimens of the same alloys show that nm-scaled α'-phase precipitates also significantly contribute to the irradiation-induced hardness increase. An Orowan model is used to estimate the obstacle strengths posed to dislocation glide by these lattice defects. The topic is stepwise extended to more complex situations with respect to the irradiation conditions and the materials. Considering simultaneous and sequential irradiations with iron- and helium-ions it is shown that the effect of helium on irradiation hardening depends on the chronological order of the irradiations and that the simultaneous introduction of helium in fusion-relevant concentrations amplifies irradiation hardening based on a synergistic effect. There is no

  14. Method for the irradiation of single targets

    International Nuclear Information System (INIS)

    Krimmel, E.; Dullnig, H.

    1977-01-01

    The invention pertains to a system for the irradiation of single targets with particle beams. The targets all have frames around them. The system consists of an automatic advance leading into a high-vacuum chamber, and a positioning element which guides one target after the other into the irradiation position, at right angles to the automatic advance, and back into the automatic advance after irradiation. (GSCH) [de

  15. Food irradiation

    International Nuclear Information System (INIS)

    Hetherington, M.

    1989-01-01

    This popular-level article emphasizes that the ultimate health effects of irradiated food products are unknown. They may include vitamin loss, contamination of food by botulism bacteria, mutations in bacteria, increased production of aflatoxins, changes in food, carcinogenesis from unknown causes, presence of miscellaneous harmful chemicals, and the lack of a way of for a consumer to detect irradiated food. It is claimed that the nuclear industry is applying pressure on the Canadian government to relax labeling requirements on packages of irradiated food in order to find a market for its otherwise unnecessary products

  16. Food irradiation

    International Nuclear Information System (INIS)

    Luecher, O.

    1979-01-01

    Limitations of existing preserving methods and possibilities of improved food preservation by application of nuclear energy are explained. The latest state-of-the-art in irradiation technology in individual countries is described and corresponding recommendations of FAO, WHO and IAEA specialists are presented. The Sulzer irradiation equipment for potato sprout blocking is described, the same equipment being suitable also for the treatment of onions, garlic, rice, maize and other cereals. Systems with a higher power degree are needed for fodder preserving irradiation. (author)

  17. A model for phase stability under irradiation

    International Nuclear Information System (INIS)

    Abromeit, C.

    The combination of two theoretical models leads to modified criteria of stability of precipitates under heavy particle irradiation. The size of existing or under irradiation newly formed precipitates is limited by a stable radius. Precipitate surface energy effects are included in a consistent manner

  18. Irradiation creep under 60 MeV alpha irradiation

    International Nuclear Information System (INIS)

    Reiley, T.C.; Shannon, R.H.; Auble, R.L.

    1980-01-01

    Accelerator-produced charged-particle beams have advantages over neutron irradiation for studying radiation effects in materials, the primary advantage being the ability to control precisely the experimental conditions and improve the accuracy in measuring effects of the irradiation. An apparatus has recently been built at ORNL to exploit this advantage in studying irradiation creep. These experiments employ a beam of 60 MeV alpha particles from the Oak Ridge Isochronous Cyclotron (ORIC). The experimental approach and capabilities of the apparatus are described. The damage cross section, including events associated with inelastic scattering and nuclear reactions, is estimated. The amount of helium that is introduced during the experiments through inelastic processes and through backscattering is reported. Based on the damage rate, the damage processes and the helium-to-dpa ratio, the degree to which fast reactor and fusion reactor conditions may be simulated is discussed. Recent experimental results on the irradiation creep of type 316 stainless steel are presented, and are compared to light ion results obtained elsewhere. These results include the stress and temperature dependence of the formation rate under irradiation. The results are discussed in relation to various irradiation creep mechanisms and to damage microstructure as it evolves during these experiments. (orig.)

  19. Efficiency of Cu{sub 2}O/BiVO{sub 4} particles prepared with a new soft procedure on the degradation of dyes under visible-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Aguilera-Ruiz, Eduardo [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, Centro de Investigación e Innovación en Ingeniería Aeronáutica, Carretera a Salinas Victoria, Km 2.3, 66600 Apodaca, NL (Mexico); García-Pérez, Ulises M., E-mail: ulisesma.garcia@gmail.com [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, Centro de Investigación e Innovación en Ingeniería Aeronáutica, Carretera a Salinas Victoria, Km 2.3, 66600 Apodaca, NL (Mexico); Garza-Galván, María de la; Zambrano-Robledo, Patricia; Bermúdez-Reyes, Bárbara [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, Centro de Investigación e Innovación en Ingeniería Aeronáutica, Carretera a Salinas Victoria, Km 2.3, 66600 Apodaca, NL (Mexico); and others

    2015-02-15

    Graphical abstract: - Highlights: • Cu{sub 2}O/BiVO{sub 4} p–n heterojunctions were synthesized by a simple impregnation method. • The photocatalytic performance was evaluated using a LED lamp as visible source. • The composite with 1 wt.% of Cu{sub 2}O exhibits the best visible-light-activity. • A mechanism for the carriers transfer is proposed. • Factors as pH and O{sub 2} were found to influence the degradation rate. - Abstract: Cu{sub 2}O/BiVO{sub 4} composites with different concentrations of Cu{sub 2}O were synthesized by a simple impregnation method at 200 °C under N{sub 2} atmosphere for 4 h. The as-synthesized samples were characterized by X-ray powder diffraction, scanning electron microscopy, UV–vis diffuse reflection absorption and vis photoluminescence. The morphology of the as-synthesized composites with different weight ratios of Cu{sub 2}O is composed by quasi-spherical and dendrite-like particles. The photocatalytic performance of the Cu{sub 2}O/BiVO{sub 4} composites was evaluated by degradation of methyl orange solutions under visible-LED irradiation. The results obtained show that the photocatalytic behavior of the p–n heterojunction Cu{sub 2}O/BiVO{sub 4} composites was better than pure Cu{sub 2}O and BiVO{sub 4}. The variation of the reaction parameters, such as solution pH and presence of O{sub 2}, improved the photocatalytic performance of Cu{sub 2}O/BiVO{sub 4} composite. Meanwhile, a possible mechanism for methyl orange photocatalytic degradation over Cu{sub 2}O/BiVO{sub 4} photocatalysts was proposed. The chemical stability and reusability of Cu{sub 2}O/BiVO{sub 4} powders were also investigated.

  20. Food irradiation

    International Nuclear Information System (INIS)

    Paganini, M.C.

    1991-06-01

    Food treatment by means of ionizing energy, or irradiation, is an innovative method for its preservation. In order to treat important volumes of food, it is necessary to have industrial irradiation installations. The effect of radiations on food is analyzed in the present special work and a calculus scheme for an Irradiation Plant is proposed, discussing different aspects related to its project and design: ionizing radiation sources, adequate civil work, security and auxiliary systems to the installations, dosimetric methods and financing evaluation methods of the project. Finally, the conceptual design and calculus of an irradiation industrial plant of tubercles is made, based on the actual needs of a specific agricultural zone of our country. (Author) [es

  1. Food irradiation

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    Food preservation by irradiation is one part of Eisenhower's Atoms for Peace program that is enjoying renewed interest. Classified as a food additive by the Food, Drug, and Cosmetic Act of 1958 instead of a processing technique, irradiation lost public acceptance. Experiments have not been done to prove that there are no health hazards from gamma radiation, but there are new pressures to get Food and Drug Administration approval for testing in order to make commercial use of some radioactive wastes. Irradiation causes chemical reactions and nutritional changes, including the destruction of several vitamins, as well as the production of radiolytic products not normally found in food that could have adverse effects. The author concludes that, lacking epidemiological evidence, willing buyers should be able to purchase irradiated food as long as it is properly labeled

  2. Fruit irradiation

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    Food spoilage is a common problem when marketing agricultural products. Promising results have already been obtained on a number of food irradiating applications. A process is described in this paper where irradiation of sub-tropical fruits, especially mangoes and papayas, combined with conventional heat treatment results in effective insect and fungal control, delays ripening and greatly improves the quality of fruit at both export and internal markets

  3. Tissue irradiator

    International Nuclear Information System (INIS)

    Hungate, F.P.; Riemath, W.F.; Bunnell, L.R.

    1975-01-01

    A tissue irradiator is provided for the in-vivo irradiation of body tissue. The irradiator comprises a radiation source material contained and completely encapsulated within vitreous carbon. An embodiment for use as an in-vivo blood irradiator comprises a cylindrical body having an axial bore therethrough. A radioisotope is contained within a first portion of vitreous carbon cylindrically surrounding the axial bore, and a containment portion of vitreous carbon surrounds the radioisotope containing portion, the two portions of vitreous carbon being integrally formed as a single unit. Connecting means are provided at each end of the cylindrical body to permit connections to blood-carrying vessels and to provide for passage of blood through the bore. In a preferred embodiment, the radioisotope is thulium-170 which is present in the irradiator in the form of thulium oxide. A method of producing the preferred blood irradiator is also provided, whereby nonradioactive thulium-169 is dispersed within a polyfurfuryl alcohol resin which is carbonized and fired to form the integral vitreous carbon body and the device is activated by neutron bombardment of the thulium-169 to produce the beta-emitting thulium-170

  4. Blood irradiation

    International Nuclear Information System (INIS)

    Chandy, Mammen

    1998-01-01

    Viable lymphocytes are present in blood and cellular blood components used for transfusion. If the patient who receives a blood transfusion is immunocompetent these lymphocytes are destroyed immediately. However if the patient is immunodefficient or immunosuppressed the transfused lymphocytes survive, recognize the recipient as foreign and react producing a devastating and most often fatal syndrome of transfusion graft versus host disease [T-GVHD]. Even immunocompetent individuals can develop T-GVHD if the donor is a first degree relative since like the Trojan horse the transfused lymphocytes escape detection by the recipient's immune system, multiply and attack recipient tissues. T-GVHD can be prevented by irradiating the blood and different centers use doses ranging from 1.5 to 4.5 Gy. All transfusions where the donor is a first degree relative and transfusions to neonates, immunosuppressed patients and bone marrow transplant recipients need to be irradiated. Commercial irradiators specifically designed for irradiation of blood and cellular blood components are available: however they are expensive. India needs to have blood irradiation facilities available in all large tertiary institutions where immunosuppressed patients are treated. The Atomic Energy Commission of India needs to develop a blood irradiator which meets international standards for use in tertiary medical institutions in the country. (author)

  5. Food irradiation

    International Nuclear Information System (INIS)

    Migdal, W.

    1995-01-01

    A worldwide standard on food irradiation was adopted in 1983 by codex Alimentarius Commission of the Joint Food Standard Programme of the Food and Agriculture Organization (FAO) of the United Nations and The World Health Organization (WHO). As a result, 41 countries have approved the use of irradiation for treating one or more food items and the number is increasing. Generally, irradiation is used to: food loses, food spoilage, disinfestation, safety and hygiene. The number of countries which use irradiation for processing food for commercial purposes has been increasing steadily from 19 in 1987 to 33 today. In the frames of the national programme on the application of irradiation for food preservation and hygienization an experimental plant for electron beam processing has been established in Inst. of Nuclear Chemistry and Technology. The plant is equipped with a small research accelerator Pilot (19 MeV, 1 kW) and industrial unit Electronika (10 MeV, 10 kW). On the basis of the research there were performed at different scientific institutions in Poland, health authorities have issued permissions for irradiation for; spices, garlic, onions, mushrooms, potatoes, dry mushrooms and vegetables. (author)

  6. Food irradiation

    International Nuclear Information System (INIS)

    1991-01-01

    Processing of food with low levels of radiation has the potential to contribute to reducing both spoilage of food during storage - a particular problem in developing countries - and the high incidence of food-borne disease currently seen in all countries. Approval has been granted for the treatment of more than 30 products with radiation in over 30 countries but, in general, governments have been slow to authorize the use of this new technique. One reason for this slowness is a lack of understanding of what food irradiation entails. This book aims to increase understanding by providing information on the process of food irradiation in simple, non-technical language. It describes the effects that irradiation has on food, and the plant and equipment that are necessary to carry it out safely. The legislation and control mechanisms required to ensure the safety of food irradiation facilities are also discussed. Education is seen as the key to gaining the confidence of the consumers in the safety of irradiated food, and to promoting understanding of the benefits that irradiation can provide. (orig.) With 4 figs., 1 tab [de

  7. Irradiation device

    International Nuclear Information System (INIS)

    Suzuki, Toshimitsu.

    1989-01-01

    In an irradiation device for irradiating radiation rays such as electron beams to pharmaceuticals, etc., since the distribution of scanned electron rays was not monitored, the electron beam intensity could be determined only indirectly and irradiation reliability was not satisfactory. In view of the above, a plurality of monitor wires emitting secondary electrons are disposed in the scanning direction near a beam take-out window of a scanning duct, signals from the monitor wires are inputted into a display device such as a cathode ray tube, as well as signals from the monitor wires at the central portion are inputted into counting rate meters to measure the radiation dose as well. Since secondary electrons are emitted when electron beams pass through the monitor wires and the intensity thereof is in proportion with the intensity of incident electron beams, the distribution of the radiation dose can be monitored by measuring the intensity of the emitted secondary electrons. Further, uneven irradiation, etc. can also be monitored to make the radiation of irradiation rays reliable. (N.H.)

  8. Food irradiation

    International Nuclear Information System (INIS)

    Beishon, J.

    1991-01-01

    Food irradiation has been the subject of concern and controversy for many years. The advantages of food irradiation include the reduction or elimination of dangerous bacterial organisms, the control of pests and insects which destroy certain foods, the extension of the shelf-life of many products, for example fruit, and its ability to treat products such as seafood which may be eaten raw. It can also replace existing methods of treatment which are believed to have hazardous side-effects. However, after examining the evidence produced by the proponents of food irradiation, the author questions whether it has any major contribution to make to the problems of foodborne diseases or world food shortages. More acceptable solutions, he suggests, may be found in educating food handlers to ensure that hygienic conditions prevail in the production, storage and serving of food. (author)

  9. Vinca irradiator

    International Nuclear Information System (INIS)

    Eymery, R.

    1976-10-01

    The development programme of the VINCA radiosterilisation centre involves plans for an irradiator capable of working in several ways. Discontinuous operation. The irradiator is loaded for a certain period then runs automatically until the moment of unloading. This method is suitable as long as the treatment capacity is relatively small. Continuous operation with permanent batch loading and unloading carried out either manually or automatically (by means of equipment to be installed later). Otherwise the design of the apparatus is highly conventional. The source is a vertical panel submersible in a pool. The conveyor is of the 'bucket' type, with 4 tiers to each bucket. The batches pass successively through all possible irradiation positions. Transfert into and out of the cell take place through a maze, which also provides access to the cell when the sources are in storage at the bottom of the pool [fr

  10. Mechanical properties of irradiated rubber-blends

    International Nuclear Information System (INIS)

    Nasr, G.M.; Madani, M.

    2005-01-01

    A study has been made on blend ratios of natural rubber (NR) and acrylonitrile butadiene rubber (NBR) that are loaded with general purpose furnace (GPE) carbon black and irradiated at different gamma radiation doses. It was fount that the mechanical properties of such blend are highly affected by γ- irradiation dose and the composition ratios of its constituents. The elongation at break for blends was found to increase slightly with increasing NBR loafing which is mainly due to the stiffness of blending matrix formation between NR and GPF carbon black particles. The hysteresis loss, extension ratio and shape factor have been calculated for the different un-irradiated and irradiated samples

  11. Irradiance gradients

    International Nuclear Information System (INIS)

    Ward, G.J.; Heckbert, P.S.; Technische Hogeschool Delft

    1992-04-01

    A new method for improving the accuracy of a diffuse interreflection calculation is introduced in a ray tracing context. The information from a hemispherical sampling of the luminous environment is interpreted in a new way to predict the change in irradiance as a function of position and surface orientation. The additional computation involved is modest and the benefit is substantial. An improved interpolation of irradiance resulting from the gradient calculation produces smoother, more accurate renderings. This result is achieved through better utilization of ray samples rather than additional samples or alternate sampling strategies. Thus, the technique is applicable to a variety of global illumination algorithms that use hemicubes or Monte Carlo sampling techniques

  12. ion irradiation

    Indian Academy of Sciences (India)

    Swift heavy ions interact predominantly through inelastic scattering while traversing any polymer medium and produce excited/ionized atoms. Here samples of the polycarbonate Makrofol of approximate thickness 20 m, spin coated on GaAs substrate were irradiated with 50 MeV Li ion (+3 charge state). Build-in ...

  13. Fish irradiation

    International Nuclear Information System (INIS)

    Kovacs, J.; Tengumnuay, C.; Juangbhanich, C.

    1970-01-01

    Chub-mackerel was chosen for the study because they are the most common fish in Thailand. Preliminary investigations were conducted to determine the maximum radiation dose of gamma-rays by organoleptic tests. The samples were subjected to radiation at various doses up to 4 Mrad. Many experiments were conducted using other kinds of fish. The results showed that 1 Mrad would be the maximum acceptable dose for fish. Later, the influence of the radiation dose from 0.1-1 Mrad was studied in order to find the optimum acceptable dose for preservation of fish without off-flavour. For this purpose, the Hedonic scale was used. It was found that 0.2 and 0.5 Mrad gave the best result on Chub mackerel. The determinations of optimum dose, organoleptic, microbiological and trimethylamine content changes were done. The results showed that Chub mackerel irradiated at 0.2, 0.5 and 1 Mrad stored at 3 0 C for 71 days were still acceptable, on the contrary the untreated samples were found unacceptable at 14 days. The trimethylamine increment was significantly higher in the untreated samples. At 15 days storage, trimethylamine in the non-irradiated Chub-mackerel was about 10 times higher than the irradiated ones. At 51 and 79 days storage, about 13 times higher in the control samples than the irradiated samples except 0.1 Mrad. Only 2 times higher was found for the 0.1 Mrad. The microbiological results showed that the irradiation above 0.2 Mrad gave favorable extension of shelf-life of fish

  14. Chapter 2: Irradiators

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2018-04-01

    The chapter 2 presents the subjects: 1) gamma irradiators which includes: Category-I gamma irradiators (self-contained); Category-II gamma irradiators (panoramic and dry storage); Category-III gamma irradiators (self-contained in water); Category-IV gamma irradiators (panoramic and wet storage); source rack for Category-IV gamma irradiators; product transport system for Category-IV gamma irradiators; radiation shield for gamma irradiators; 2) accelerators which includes: Category-I Accelerators (shielded irradiator); Category-II Accelerators (irradiator inside a shielded room); Irradiation application examples.

  15. Irradiation plant for flowable material

    International Nuclear Information System (INIS)

    Bosshard, E.

    1975-01-01

    The irradiation plant can be used to treat various flowable materials including effluent or sewage sludge. The plant contains a concrete vessel in which a partition is mounted to form two coaxial irradiation chambers through which the flowable material can be circulated by means of an impeller. The partition can be formed to house tubes of radiation sources and to provide a venturi-like member about the impeller. The operation of the impeller is reversed periodically to assure movement of both heavy and light particles in the flow. (U.S.)

  16. Food irradiation: An update

    International Nuclear Information System (INIS)

    Morrison, Rosanna M.

    1984-01-01

    Recent regulatory and commercial activity regarding food irradiation is highlighted. The effects of irradiation, used to kill insects and microorganisms which cause food spoilage, are discussed. Special attention is given to the current regulatory status of food irradiation in the USA; proposed FDA regulation regarding the use of irradiation; pending irradiation legislation in the US Congress; and industrial applications of irradiation

  17. Method of altering the friability of abrasive particles

    International Nuclear Information System (INIS)

    Caveney, R.J.

    1978-01-01

    The invention provides a method of decreasing the friability of diamond particles of the SD, MD or RD types or cubic boron nitride particles by subjecting the particles to an irradiation so as to cause internal defects in the particles. Higher impact resistance results from this decrease in friability

  18. Rare particles

    International Nuclear Information System (INIS)

    Kutschera, W.

    1984-01-01

    The use of Accelerator Mass Spectrometry (AMS) to search for hypothetical particles and known particles of rare processes is discussed. The hypothetical particles considered include fractionally charged particles, anomalously heavy isotopes, and superheavy elements. The known particles produced in rare processes discussed include doubly-charged negative ions, counting neutrino-produced atoms in detectors for solar neutrino detection, and the spontaneous emission of 14 C from 223 Ra. 35 references

  19. Food irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Beerens, H [Lille-1 Univ., 59 - Villeneuve-d' Ascq (France); Saint-Lebe, L

    1979-01-01

    Various aspects of food treatment by cobalt 60 or caesium 137 gamma radiation are reviewed. One of the main applications of irradiation on foodstuffs lies in its ability to kill micro-organisms, lethal doses being all the lower as the organism concerned is more complex. The effect on parasites is also spectacular. Doses of 200 to 300 krad are recommended to destroy all parasites with no survival period and no resistance phenomenon has ever been observed. The action of gamma radiation on macromolecules was also investigated, the bactericide treatment giving rise to side effects by transformation of food components. Three examples were studied: starch, nucleic acids and a whole food, the egg. The organoleptic aspect of irradiation was examined for different treated foods, then the physical transformations of unpasteurized, heat-pasteurized and radio-pasteurized eggs were compared. The report ends with a brief analysis of the toxicity and conditions of application of the treatment.

  20. Irradiation device

    International Nuclear Information System (INIS)

    Ransohoff, J.A.

    1984-01-01

    Carriers, after being loaded with product to be irradiated, are transported by an input-output conveyor system into an irradiation chamber where they are received in a horizontal arrangement on racks which may support different sizes and numbers of carriers. The racks are moved by a chamber conveyor system in an endless rectangular path about a radiation source. Packers shift the carriers on the racks to maintain nearest proximity to the radiation source. The carriers are shifted in position on each rack during successive rack cycles to produce even radiation exposure. The carriers may be loaded singly onto successive racks during a first cycle of movement thereof about the source, with loading of additional carriers, and/or unloading of carriers, onto each rack occurring on subsequent rack cycles of movement

  1. Food irradiation

    International Nuclear Information System (INIS)

    Roberts, P.B.

    1997-01-01

    Food can be provided with extra beneficial properties by physical processing. These benefits include a reduced possibility of food poisoning, or an increased life of the food. We are familiar with pasteurisation of milk, drying of vegetables, and canning of fruit. These physical processes work because the food absorbs energy during treatment which brings about the changes needed. The energy absorbed in these examples is heat energy. Food irradiation is a less familiar process. It produces similar benefits to other processes and it can sometimes be applied with additional advantages over conventional processing. For example, because irradiation causes little heating, foods may look and taste more natural. Also, treatment can take place with the food in its final plastic wrappers, reducing the risk of re-contamination. (author). 1 ref., 4 figs., 1 tab

  2. Food irradiation

    International Nuclear Information System (INIS)

    Beerens, H.; Saint-Lebe, L.

    1979-01-01

    Various aspects of food treatment by cobalt 60 or caesium 137 gamma radiation are reviewed. One of the main applications of irradiation on foodstuffs lies in its ability to kill micro-organisms, lethal doses being all the lower as the organism concerned is more complex. The effect on parasites is also spectacular. Doses of 200 to 300 krad are recommended to destroy all parasites with no survival period and no resistance phenomenon has ever been observed. The action of gamma radiation on macromolecules was also investigated, the bactericide treatment giving rise to side effects by transformation of food components. Three examples were studied: starch, nucleic acids and a whole food, the egg. The organoleptic aspect of irradiation was examined for different treated foods, then the physical transformations of unpasteurized, heat-pasteurized and radio-pasteurized eggs were compared. The report ends with a brief analysis of the toxicity and conditions of application of the treatment [fr

  3. Endolymphatic irradiation

    International Nuclear Information System (INIS)

    Galvao, M.M.; Ianhez, L.E.; Sabbaga, E.

    1982-01-01

    The authors analysed the clinical evolution and the result of renal transplantation some years after irradiation in 24 patients (group I) who received endolymphatic 131 I as a pre-transplantation immunesuppresive measure. The control group (group II) consisted of 24 non-irradiated patients comparable to group I in age, sex, primary disease, type of donor and immunesuppressive therapy. Significant differences were observed between the two groups regarding such factors a incidence and reversibility of rejection crises in the first 60 post-transplantation days, loss of kidney due to rejection, and dosage of azathioprine. The authors conclude that this method, besides being harmless, has prolonged immunesuppressive action, its administration being advised for receptores of cadaver kidneys, mainly those who show positive cross-match against HLA antigens for painel. (Author) [pt

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

    International Nuclear Information System (INIS)

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

    1977-01-01

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

  5. Effect of irradiation on functional properties of Gum Tragacanth

    Directory of Open Access Journals (Sweden)

    Neda Mollakhalili meybodi

    2017-03-01

    Full Text Available Background and objective: irradiation is a physical treatment in which products are exposed to ionized radiation such as gamma and x rays to improve the security and quality. Hydrocolloids are components that are used in food science to improve texture properties. Exposing to irradiation treatment may change structural and functional properties. By regard to the importance of irradiation on decontaminating of hydrocolloids in food application, the aim of this study is studying the effect of irradiation at different doses on functional properties of Gum Tragacanth in food application. Material and methods: effect of irradiation treatment was studied on the rheological properties, zeta potential, particle size distribution and surface tension of dispersion systems contained 0/5% w/ w gum tragacanth that is irradiated at different doses (0, 0.75. 3, 5 kGy. The effect of irradiation on rheological properties was monitored by rheometer. In order to monitor the effect of irradiation treatment on particle size distribution, zeta potential and surface tension, particle sizer, Brookhaven zeta plus and tensiometer sere used respectively. All treatments were performed three times and the data were analyzed by one way ANOVA. Significant differences between means were identified (P values < 0.05 using Duncan test. Results: Irradiation, change rheologiacal properties and particle size distribution of dispersion contained gum tragacanth. Irradiation treatment up to 0.75 kGy increase zeta potential, but irradiating at higher doses decrease it again. Results of studying parameters showed that irradiation changes the functional properties by affecting on structure. These changes depend on irradiation dose Conclusion: Gum tragacanth irradiation may improve the functional properties by affecting on structure.

  6. Ions irradiation on bi-layer coatings

    Science.gov (United States)

    Tessarolo, Enrico; Corso, Alain Jody; Böttger, Roman; Martucci, Alessandro; Pelizzo, Maria G.

    2017-09-01

    Future space missions will operate in very harsh and extreme environments. Optical and electronics components need to be optimized and qualified in view of such operational challenges. This work focuses on the effect of low alpha particles irradiation on coatings. Low energy He+ (4 keV and 16 keV) ions have been considered in order to simulate in laboratory the irradiation of solar wind (slow and fast components) alpha particles. Mono- and proper bi-layers coatings have been investigated. The experimental tests have been carried out changing doses as well as fluxes during the irradiation sessions. Optical characterization in the UV-VIS spectral range and superficial morphological analysis have performed prior and after irradiation.

  7. Particle detection

    International Nuclear Information System (INIS)

    Charpak, G.

    2000-01-01

    In this article G.Charpak presents the principles on which particle detection is based. Particle accelerators are becoming more and more powerful and require new detectors able to track the right particle in a huge flux of particles. The gigantic size of detectors in high energy physics is often due to the necessity of getting a long enough trajectory in a magnetic field in order to deduce from the curvature an accurate account of impulses in the reaction. (A.C.)

  8. Strange particles

    International Nuclear Information System (INIS)

    Chinowsky, W.

    1989-01-01

    Work done in the mid 1950s at Brookhaven National Laboratory on strange particles is described. Experiments were done on the Cosmotron. The author describes his own and others' work on neutral kaons, lambda and theta particles and points out the theoretical gap between predictions and experimental findings. By the end of the decade, the theory of strange particles was better understood. (UK)

  9. Mechanical properties of irradiated beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Beeston, J.M.; Longhurst, G.R.; Wallace, R.S. (EG and G Idaho, Inc., Idaho Falls, ID (United States). Idaho National Engineering Lab.); Abeln, S.P. (EG and G Rocky Flats, Inc., Golden, CO (United States))

    1992-10-01

    Beryllium is planned for use as a neutron multiplier in the tritium breeding blanket of the International Thermonuclear Experimental Reactor (ITER). After fabricating samples of beryllium at densities varying from 80 to 100% of the theoretical density, we conducted a series of experiments to measure the effect of neutron irradiation on mechanical properties, especially strength and ductility. Samples were irradiated in the Advanced Test Reactor (ATR) to a neutron fluence of 2.6 x 10[sup 25] n/m[sup 2] (E > MeV) at an irradiation temperature of 75deg C. These samples were subsequently compression-tested at room temperature, and the results were compared with similar tests on unirradiated specimens. We found that the irradiation increased the strength by approximately four times and reduced the ductility to approximately one fourth. Failure was generally ductile, but the 80% dense irradiated samples failed in brittle fracture with significant generation of fine particles and release of small quantities of tritium. (orig.).

  10. Irradiance Impact on Pollution by Integrating Nephelometer Measurements

    Directory of Open Access Journals (Sweden)

    Maria Rita Perrone

    2015-12-01

    Full Text Available Three-wavelength integrating nephelometer measurements combined with short- (SW and long-wave (LW irradiance measurements were used to investigate the irradiance effects on the daily evolution of the particulate matter (PM at the ground level, and contribute to the characterization of the land–atmosphere interaction in pollution dispersal. The integrating nephelometer measurements have allowed characterizing the daily changes of the PM optical and microphysical properties by the aerosol scattering coefficient (σp and the scattering Ångström coefficient (å. We found that on a daily basis σp reached the minimum values when the irradiance reached the maximum values, since the convective motions, which favor the particle dispersion at the surface, increase with the irradiance. The å value, which is commonly used as qualitative indicator of the dominant particle size, has allowed evaluating the irradiance effects on the mean particle size distribution at the surface and revealed that the irradiance increase favors mainly the dispersion of the ground-level fine particles. Particle size-distribution measurements supported the last comment. Measurements were performed from 4 to 10 May 2015 when the study site was affected by a Saharan dust outbreak, to also evaluate the impact of long-range transported particles on the daily evolution of the ground-level particle’s properties and the SW and LW irradiance.

  11. Colloidal assemblies modified by ion irradiation

    OpenAIRE

    Snoeks, E.; Blaaderen, A. van; Dillen, T. van; Kats, C.M. van; Velikov, K.P.; Brongersma, M.L.; Polman, A.

    2001-01-01

    Spherical SiO2 and ZnS colloidal particles show a dramatic anisotropic plastic deformation under 4 MeV Xe ion irradiation, that changes their shape into oblate into oblate ellipsional, with an aspect ratio that can be precisely controlled by the ion fluence. The 290 nm and 1.1 um diameter colloids were deposited on a Si substrate and irradiated at 90 K, using fluences in the range 3*10^(13)-8*10^(14) cm^(-2). The transverse particle diameter shows a linear increase with ion fluence, while the...

  12. Emulation of neutron irradiation effects with protons: validation of principle

    International Nuclear Information System (INIS)

    Was, G.S.; Busby, J.T.; Allen, T.; Kenik, E.A.; Jensson, A.; Bruemmer, S.M.; Gan, J.; Edwards, A.D.; Scott, P.M.; Andreson, P.L.

    2002-01-01

    This paper presents the results of the irradiation, characterization and irradiation assisted stress corrosion cracking (IASCC) behavior of proton- and neutron-irradiated samples of 304SS and 316SS from the same heats. The objective of the study was to determine whether proton irradiation does indeed emulate the full range of effects of in-reactor neutron irradiation: radiation-induced segregation (RIS), irradiated microstructure, radiation hardening and IASCC susceptibility. The work focused on commercial heats of 304 stainless steel (heat B) and 316 stainless steel (heat P). Irradiation with protons was conducted at 360 deg. C to doses between 0.3 and 5.0 dpa to approximate those by neutron irradiation at 275 deg. C over the same dose range. Characterization consisted of grain boundary microchemistry, dislocation loop microstructure, hardness as well as stress corrosion cracking (SCC) susceptibility of both un-irradiated and irradiated samples in oxygenated and de-oxygenated water environments at 288 deg. C. Overall, microchemistry, microstructure, hardening and SCC behavior of proton- and neutron-irradiated samples were in excellent agreement. RIS analysis showed that in both heats and for both irradiating particles, the pre-existing grain boundary Cr enrichment transformed into a 'W' shaped profile at 1.0 dpa and then into a 'V' shaped profile between 3.0 and 5.0 dpa. Grain boundary segregation of Cr, Ni, Si, and Mo all followed the same trends and agreed well in magnitude. The microstructure of both proton- and neutron-irradiated samples was dominated by small, faulted dislocation loops. Loop size distributions were nearly identical in both heats over a range of doses. Saturated loop size following neutron irradiation was about 30% larger than that following proton irradiation. Loop density increased with dose through 5.0 dpa for both particle irradiations and was a factor of 3 greater in neutron-irradiated samples vs. proton-irradiated samples. Grain boundary

  13. KEY RESULTS FROM IRRADIATION AND POST-IRRADIATION EXAMINATION OF AGR-1 UCO TRISO FUEL

    Energy Technology Data Exchange (ETDEWEB)

    Demkowicz, Paul A.; Hunn, John D.; Petti, David A.; Morris, Robert N.

    2016-11-01

    The AGR-1 irradiation experiment was performed as the first test of tristructural isotropic (TRISO) fuel in the US Advanced Gas Reactor Fuel Development and Qualification Program. The experiment consisted of 72 right cylinder fuel compacts containing approximately 3×105 coated fuel particles with uranium oxide/uranium carbide (UCO) fuel kernels. The fuel was irradiated in the Advanced Test Reactor for a total of 620 effective full power days. Fuel burnup ranged from 11.3 to 19.6% fissions per initial metal atom and time average, volume average irradiation temperatures of the individual compacts ranged from 955 to 1136°C. This paper focuses on key results from the irradiation and post-irradiation examination, which revealed a robust fuel with excellent performance characteristics under the conditions tested and have significantly improved the understanding of UCO coated particle fuel irradiation behavior within the US program. The fuel exhibited a very low incidence of TRISO coating failure during irradiation and post-irradiation safety testing at temperatures up to 1800°C. Advanced PIE methods have allowed particles with SiC coating failure to be isolated and meticulously examined, which has elucidated the specific causes of SiC failure in these specimens. The level of fission product release from the fuel during irradiation and post-irradiation safety testing has been studied in detail. Results indicated very low release of krypton and cesium through intact SiC and modest release of europium and strontium, while also confirming the potential for significant silver release through the coatings depending on irradiation conditions. Focused study of fission products within the coating layers of irradiated particles down to nanometer length scales has provided new insights into fission product transport through the coating layers and the role various fission products may have on coating integrity. The broader implications of these results and the application of

  14. Biology of food irradiation

    International Nuclear Information System (INIS)

    Murray, D.R.

    1990-01-01

    The author presents his arguments for food scientists and biologists that the hazards of food irradiation outweigh the benefits. The subject is discussed in the following sections: introduction (units, mutagenesis, seed viability), history of food irradiation, effects of irradiation on organoleptic qualities of staple foods, radiolytic products and selective destruction of nutrients, production of microbial toxins in stored irradiated foods and loss of quality in wheat, deleterious consequences of eating irradiated foods, misrepresentation of the facts about food irradiation. (author)

  15. Effects of alpha particles on zebrafish embryos

    International Nuclear Information System (INIS)

    Yum, E.H.W.; Choi, V.W.Y.; Yu, K.N.; Li, V.W.T.; Cheng, S.H.

    2008-01-01

    Full text: Ionizing radiation such as X-ray and alpha particles can damage cellular macromolecules, which can lead to DNA single- and double-strand breaks. In the present work, we studied the effects of alpha particles on dechorionated zebrafish embryos. Thin polyallyldiglycol carbonate (PADC) films with a thickness of 16 μm were prepared from commercially available PADC films (with thickness of 100 μm) by chemical etching and used as support substrates for holding zebrafish embryos for alpha-particle irradiation. These films recorded alpha-particle hit positions, quantified the number and energy of alpha particles actually incident on the embryo cells, and thus enabled the calculation of the dose absorbed by the embryo cells. Irradiation was made at 1.25 hours post fertilization (hpf) with various absorbed dose. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was performed on the embryos at different time stages after irradiation. Marked apoptosis was detected only in embryos at earlier time stages. The results showed that DNA double-strand break during zebrafish embryogenesis can be induced by alpha-particle irradiation, which suggests that zebrafish is a potential model for assessing the effects of alpha-particle radiation

  16. Particle therapy

    Energy Technology Data Exchange (ETDEWEB)

    Raju, M.R.

    1993-09-01

    Particle therapy has a long history. The experimentation with particles for their therapeutic application got started soon after they were produced in the laboratory. Physicists played a major role in proposing the potential applications in radiotherapy as well as in the development of particle therapy. A brief review of the current status of particle radiotherapy with some historical perspective is presented and specific contributions made by physicists will be pointed out wherever appropriate. The rationale of using particles in cancer treatment is to reduce the treatment volume to the target volume by using precise dose distributions in three dimensions by using particles such as protons and to improve the differential effects on tumors compared to normal tissues by using high-LET radiations such as neutrons. Pions and heavy ions combine the above two characteristics.

  17. Particle therapy

    International Nuclear Information System (INIS)

    Raju, M.R.

    1993-01-01

    Particle therapy has a long history. The experimentation with particles for their therapeutic application got started soon after they were produced in the laboratory. Physicists played a major role in proposing the potential applications in radiotherapy as well as in the development of particle therapy. A brief review of the current status of particle radiotherapy with some historical perspective is presented and specific contributions made by physicists will be pointed out wherever appropriate. The rationale of using particles in cancer treatment is to reduce the treatment volume to the target volume by using precise dose distributions in three dimensions by using particles such as protons and to improve the differential effects on tumors compared to normal tissues by using high-LET radiations such as neutrons. Pions and heavy ions combine the above two characteristics

  18. Particle cosmology

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    The understanding of the Universe at the largest and smallest scales traditionally has been the subject of cosmology and particle physics, respectively. Studying the evolution of the Universe connects today's large scales with the tiny scales in the very early Universe and provides the link between the physics of particles and of the cosmos. This series of five lectures aims at a modern and critical presentation of the basic ideas, methods, models and observations in today's particle cosmology.

  19. Particle physics

    International Nuclear Information System (INIS)

    Kamal, Anwar

    2014-01-01

    Provides step-by-step derivations. Contains numerous tables and diagrams. Supports learning and teaching with numerous worked examples, questions and problems with answers. Sketches also the historical development of the subject. This textbook teaches particle physics very didactically. It supports learning and teaching with numerous worked examples, questions and problems with answers. Numerous tables and diagrams lead to a better understanding of the explanations. The content of the book covers all important topics of particle physics: Elementary particles are classified from the point of view of the four fundamental interactions. The nomenclature used in particle physics is explained. The discoveries and properties of known elementary particles and resonances are given. The particles considered are positrons, muon, pions, anti-protons, strange particles, neutrino and hadrons. The conservation laws governing the interactions of elementary particles are given. The concepts of parity, spin, charge conjugation, time reversal and gauge invariance are explained. The quark theory is introduced to explain the hadron structure and strong interactions. The solar neutrino problem is considered. Weak interactions are classified into various types, and the selection rules are stated. Non-conservation of parity and the universality of the weak interactions are discussed. Neutral and charged currents, discovery of W and Z bosons and the early universe form important topics of the electroweak interactions. The principles of high energy accelerators including colliders are elaborately explained. Additionally, in the book detectors used in nuclear and particle physics are described. This book is on the upper undergraduate level.

  20. Magnetic particles

    Science.gov (United States)

    Chang, Manchium (Inventor); Colvin, Michael S. (Inventor)

    1989-01-01

    Magnetic polymer particles are formed by swelling porous, polymer particles and impregnating the particles with an aqueous solution of precursor magnetic metal salt such as an equimolar mixture of ferrous chloride and ferric chloride. On addition of a basic reagent such as dilute sodium hydroxide, the metal salts are converted to crystals of magnetite which are uniformly contained througout the pores of the polymer particle. The magnetite content can be increased and neutral buoyancy achieved by repetition of the impregnaton and neutralization steps to adjust the magnetite content to a desired level.

  1. Particle accelerator

    International Nuclear Information System (INIS)

    Ress, R.I.

    1976-01-01

    Charged particles are entrained in a predetermined direction, independent of their polarity, in a circular orbit by a magnetic field rotating at high speed about an axis in a closed cylindrical or toroidal vessel. The field may be generated by a cylindrical laser structure, whose beam is polygonally reflected from the walls of an excited cavity centered on the axis, or by high-frequency energization of a set of electromagnets perpendicular to the axis. In the latter case, a separate magnetostatic axial field limits the orbital radius of the particles. These rotating and stationary magnetic fields may be generated centrally or by individual magnets peripherally spaced along its circular orbit. Chemical or nuclear reactions can be induced by collisions between the orbiting particles and an injected reactant, or by diverting high-speed particles from one doughnut into the path of counterrotating particles in an adjoining doughnut

  2. Irradiation Facilities at CERN

    CERN Document Server

    Gkotse, Blerina; Carbonez, Pierre; Danzeca, Salvatore; Fabich, Adrian; Garcia, Alia, Ruben; Glaser, Maurice; Gorine, Georgi; Jaekel, Martin, Richard; Mateu,Suau, Isidre; Pezzullo, Giuseppe; Pozzi, Fabio; Ravotti, Federico; Silari, Marco; Tali, Maris

    2017-01-01

    CERN provides unique irradiation facilities for applications in many scientific fields. This paper summarizes the facilities currently operating for proton, gamma, mixed-field and electron irradiations, including their main usage, characteristics and information about their operation. The new CERN irradiation facilities database is also presented. This includes not only CERN facilities but also irradiation facilities available worldwide.

  3. Particle size effect on microwave absorbing of La0.67Ba0.33Mn0.94Ti0.06O3 powders prepared by mechanical alloying with the assistance of ultrasonic irradiation

    International Nuclear Information System (INIS)

    Saptari, Sitti Ahmiatri; Manaf, Azwar; Kurniawan, Budhy

    2016-01-01

    Doped manganites have attracted substantial interest due to their unique chemical and physics properties, which makes it possible to be used for microwave absorbing materials. In this paper we report synthesizes and characterization of La 0.67 Ba 0.33 Mn 0.94 Ti 0.06 O 3 powders prepared by mechanical alloying with the assistance of a high power ultrasonic treatment. After solid state reaction, the presence of single phase was confirmed by X-ray Diffraction (XRD). Refinement results showed that samples are single phase with monoclinic structure. It was found that powder materials derived from mechanical alloying results in large variation in the particle size. A significant improvement was obtained upon subjecting the mechanically milled powder materials to an ultrasonication treatment for a relatively short period of time. As determined by particle size analyzer (PSA), the mean particle size gradually decreased from the original size of 5.02 µm to 0.36 µm. Magnetic properties were characterized by VSM, and hysteresis loops results showed that samples are soft magnetic. It was found that when the mean particle size decreases, saturation was increases and coersitivity was decreases. Microwave absorption properties were investigated in the frequency range of 8-12 GHz using vector network analyzer. An optimal reflection loss of 24.44 dB is reached at 11.4 GHz.

  4. Perspective on food irradiation

    International Nuclear Information System (INIS)

    Newsome, R.L.

    1987-01-01

    A brief review summarizes current scientific information on the safety and efficacy of irradiation processing of foods. Attention is focused on: specifics of the irradiation process and its effectiveness in food preservation; the historical development of food irradiation technology in the US; the response of the Institute of Food Technologists to proposed FDA guidelines for food irradiation; the potential uses of irradiation in the US food industry; and the findings of the absence of toxins and of unaltered nutrient density (except possibly for fats) in irradiated foods. The misconceptions of consumers concerning perceived hazards associated with food irradiation, as related to consumer acceptance, also are addressed

  5. Colloidal assemblies modified by ion irradiation

    NARCIS (Netherlands)

    Snoeks, E.; Blaaderen, A. van; Dillen, T. van; Kats, C.M. van; Velikov, K.P.; Brongersma, M.L.; Polman, A.

    2001-01-01

    Spherical SiO2 and ZnS colloidal particles show a dramatic anisotropic plastic deformation under 4 MeV Xe ion irradiation, that changes their shape into oblate into oblate ellipsional, with an aspect ratio that can be precisely controlled by the ion fluence. The 290 nm and 1.1 um diameter colloids

  6. Irradiation behavior evaluation of oxide dispersion strengthened ferritic steel cladding tubes irradiated in JOYO

    Energy Technology Data Exchange (ETDEWEB)

    Yamashita, Shinichiro, E-mail: yamashita.shinichiro@jaea.go.jp; Yano, Yasuhide; Ohtsuka, Satoshi; Yoshitake, Tsunemitsu; Kaito, Takeji; Koyama, Shin-ichi; Tanaka, Kenya

    2013-11-15

    Irradiation behavior of ODS steel cladding tubes was evaluated for the further progress in understanding of the neutron-irradiation effects on ODS steel. Two types of ODS (9Cr–ODS{sub F}/M, 12Cr–ODS{sub F}) steel cladding tubes with differences in basic compositions and matrix phases were irradiated in JOYO. Post-irradiation examination data concerning hardness, ring tensile property, and microstructure were obtained. Hardness measurement after irradiation showed that there was an apparent irradiation temperature dependence on hardness for 9Cr–ODS{sub F}/M steel whereas no distinct temperature dependence for 12Cr–ODS{sub F} steel. Also, there was no significant change in tensile strengths after irradiation below 923 K, but those above 1023 K up to 6.6 × 10{sup 26} n/m{sup 2} (E > 0.1 MeV) were decreased by about 20%. TEM observations showed that the radiation-induced defect cluster formation during irradiation was suppressed because of high density sink site for defect such as initially-existed dislocation, and precipitate interfaces. In addition, oxide particles were stable up to the maximum doses of this irradiation test.

  7. Irradiation-enhanced and-induced mass transport

    International Nuclear Information System (INIS)

    Rehn, L.E.

    1989-01-01

    Irradiation can be used to enhance diffusion, that is, to increase the rate at which equilibrium is attained, as well as to induce nonequilibrium changes. The main factors influencing whether irradiation will drive a material toward or away from equilibrium are the initial specimen microstructure and geometry, irradiation temperature, and primary recoil spectrum. This paper summarizes known effects of irradiation temperature and primary recoil spectrum on mass transport during irradiation. In comparison to either electron or heavy-ion irradiation, it is concluded that relatively low-energy, light-ion bombardment at intermediate temperatures offers the greatest potential to enhance the rate at which equilibrium is attained. The greatest departures from equilibrium can be expected from irradiation with similar particles at very low temperatures

  8. Ductility loss of ion-irradiated zircaloy-2 in iodine

    International Nuclear Information System (INIS)

    Shimada, M.; Terasawa, M.; Yamamoto, S.; Kamei, H.; Koizumi, K.

    1981-01-01

    An ion bombardment simulation technique for neutron irradiation was applied to 'thick' materials to study the effect of radiation damage on the ductility change in Zircaloy-2 in an iodine environment. Specimens were prepared from actual cladding tubes and, prior to the irradiation, they were heat-treated in vacuo at 450, 580, and 700/degree/C for 2 h. Irradiation was performed by 52-MeV alpha particles up to the 0.32 displacements per atom (dpa) at 340/degree/C. Ductility loss begins to appear after 0.03 dpa irradiation, both in iodine and argon gas environments. The iodine presence resulted in ductility reduction, compared with the argon result in all irradiation dose ranges examined. The stress applied during irradiation caused ductility loss to commence at lower dosage than in the case of stress-free irradiation. These results are discussed in relation to the existing stress corrosion cracking models

  9. Alpha particle radiography of small insects

    International Nuclear Information System (INIS)

    Chingshen Su

    1993-01-01

    Radiographies of ants, mosquitoes, cockroaches and small bugs have been done with a radioisotope 244 Cm alpha source. Energy of alpha particles was varied by attenuating the 5.81 MeV alpha particles with adjustable air spacings from the source to the sample. The LR-115 was used to register radiographs. The image of the insect registered on the LR-115 was etched out in a 2.5 N NaOH solution at 52 o C for certain minutes, depending on various irradiation conditions for the insects. For larger insects, a scanning device for the alpha particle irradiation has been fabricated to take the radiograph of whole body of the insect, and the scanning period can be selected to give desired irradiation dosage. A CCDTV camera system connected to a microscope interfaced to an IBM/AT computer is used to register the microscopic image of the radiograph and to print it out with a video copy processor. (Author)

  10. Particle detectors

    CERN Document Server

    Hilke, Hans Jürgen

    1992-01-01

    We shall discuss the principles of the main techniques applied to particle detection (including front-end electronics), the construction and performance of some of the devices presently in operation and a few ideas on future developments.

  11. Auroral particles

    International Nuclear Information System (INIS)

    Evans, D.S.

    1987-01-01

    The problems concerning the aurora posed prior to the war are now either solved in principle or were restated in a more fundamental form. The pre-war hypothesis concerning the nature of the auroral particles and their energies was fully confirmed, with the exception that helium and oxygen ions were identified as participating in the auroral particle precipitation in addition to the protons. The nature of the near-Earth energization processes affecting auroral particles was clarified. Charged particle trajectories in various electric field geometries were modeled. The physical problems have now moved from determining the nature and geometry of the electric fields, which accelerate charged particles near the Earth, to accounting for the existence of these electric fields as a natural consequence of the solar wind's interaction with Earth. Ultimately the reward in continuing the work in auroral and magnetospheric particle dynamics will be a deeper understanding of the subtleties of classical electricity and magnetism as applied to situations not blessed with well-defined and invariant geometries

  12. Study of charge transport in silicon detectors: Non-irradiated and irradiated

    International Nuclear Information System (INIS)

    Leroy, C.; Roy, P.; Casse, G.; Glaser, M.; Grigoriev, E.; Lemeilleur, F.

    1999-01-01

    The electrical characteristics of silicon detectors (standard planar float zone and MESA detectors) as a function of the particle fluence can be extracted by the application of a model describing the transport of charge carriers generated in the detectors by ionizing particles. The current pulse response induced by α and β particles in non-irradiated detectors and detectors irradiated up to fluences PHI ∼ 3 · 10 14 particles/cm 2 is reproduced via this model: i) by adding a small n-type region 15 μm deep on the p + side for the detectors at fluences beyond the n to p-type inversion and ii) for the MESA detectors, by considering one additional dead layer of 14 μm (observed experimentally) on each side of the detector, and introducing a second (delayed) component to the current pulse response. For both types of detectors, the model gives mobilities decreasing linearily up to fluences of about 5·10 13 particles/cm 2 and converging, beyond, to saturation values of about 1050 cm 2 /Vs and 450 cm 2 /Vs for electrons and holes, respectively. At a fluence PHI ∼ 10 14 particles/cm 2 (corresponding to about ten years of operation at the CERN-LHC), charge collection deficits of about 14% for β particles, 25% for α particles incident on the front and 35% for α particles incident on the back of the detector are found for both type of detectors

  13. Electron beam irradiating device

    Energy Technology Data Exchange (ETDEWEB)

    Shinohara, K

    1969-12-20

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

  14. Irradiation response of ODS Eurofer97 steel

    Energy Technology Data Exchange (ETDEWEB)

    Luzginova, N.V., E-mail: luzginova@nrg.eu [Nuclear Research and Consultancy Group, Petten (Netherlands); Nolles, H.S.; Pierick, P. ten; Bakker, T.; Mutnuru, R.K.; Jong, M.; Blagoeva, D.T. [Nuclear Research and Consultancy Group, Petten (Netherlands)

    2012-09-15

    Oxide dispersion strengthened (ODS) Eurofer97 steel (EU batch, 0.3 wt.% of Y{sub 2}O{sub 3} particles), produced by mechanical alloying followed by hot rolling, is irradiated in the High Flux Reactor in Petten, The Netherlands at three different irradiation temperatures (300, 450 and 550 Degree-Sign C) up to nominal doses of 1 dpa and 3 dpa. The effect of neutron irradiation on the mechanical properties of ODS Eurofer97 material is investigated. It is shown that the irradiation hardening of ODS Eurofer97 steel occurs at 300 Degree-Sign C, whereas during irradiation at 450 and 550 Degree-Sign C no changes in mechanical properties are observed compared to the unirradiated material. This effect is possibly a result of the annealing of the irradiation damage at temperatures higher than 300 Degree-Sign C. The observed shifts in the Ductile to Brittle Transition Temperatures due to irradiation at different temperatures are discussed and compared with non-ODS Eurofer97 steel.

  15. Reproductive survival and hypoxic protection as a function of radiation ionization density. Further studies with murine leukemia cells irradiated in vitro with monoenergetic accelerated charged particles and assayed in vivo

    International Nuclear Information System (INIS)

    Berry, R.J.

    1977-01-01

    Murine lymphocytic leukemia P-388 cells have been irradiated in vitro under aerobic or hypoxic conditions with monoenergetic track segments of beams of accelerated helium or boron ions, and survival of their reproductive capacity assessed in vivo. These cells showed a maximum cell killing per rad at a relatively low ionization density (ca. 60--80 keV/μm) and their response ceased to depend on the presence or absence of oxygen at all LET values above ea. 100 keV/μm. This is similar to the LET dependence of cell killing reported recently for human lymphocytes which die a nonreproductive interphase death, and differs from the response of human kidney-derived cells which have been studied in vitro by other workers. The significance of these differences in predicting the response of cells and tissues to radiations such as fast neutrons or pi - mesons which produce wide spectra of ionization densities is discussed briefly

  16. Elementary particles and particle interactions

    International Nuclear Information System (INIS)

    Bethge, K.; Schroeder, U.E.

    1986-01-01

    This book is a textbook for an introductory course of elementary particle physics. After a general introduction the symmetry principles governing the interactions of elementary particles are discussed. Then the phenomenology of the electroweak and strong interactions are described together with a short introduction to the Weinberg-Salam theory respectively to quantum chromodynamics. Finally a short outlook is given to grand unification with special regards to SU(5) and cosmology in the framework of the current understanding of the fundamental principles of nature. In the appendix is a table of particle properties and physical constants. (HSI) [de

  17. Thermoluminescence of Simulated Interstellar Matter after Gamma-ray Irradiation

    OpenAIRE

    Koike, K.; Nakagawa, M.; Koike, C.; Okada, M.; Chihara, H.

    2002-01-01

    Interstellar matter is known to be strongly irradiated by radiation and several types of cosmic ray particles. Simulated interstellar matter, such as forsterite $\\rm Mg_{2}SiO_{4}$, enstatite $\\rm MgSiO_{3}$ and magnesite $\\rm MgCO_{3}$ has been irradiated with the $\\rm ^{60}Co$ gamma-rays in liquid nitrogen, and also irradiated with fast neutrons at 10 K and 70 K by making use of the low-temperature irradiation facility of Kyoto University Reactor (KUR-LTL. Maximum fast neutron dose is $10^{...

  18. Lattice damage caused by the irradiation of diamond

    CERN Document Server

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

    2002-01-01

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

  19. Irradiation creep of candidate materials for advanced nuclear plants

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J., E-mail: jiachao.chen@psi.ch; Jung, P.; Hoffelner, W.

    2013-10-15

    In the present paper, irradiation creep results of an intermetallic TiAl alloy and two ferritic oxide dispersion strengthened (ODS) steels are summarized. In situ irradiation creep measurements were performed using homogeneous implantation with α- and p-particles to maximum doses of 0.8 dpa at displacement damage rates of 2–8 × 10{sup −6} dpa/s. The strains of miniaturized flat dog-bone specimens were monitored under uniaxial tensile stresses ranging from 20 to 400 MPa at temperatures of 573, 673 and 773 K, respectively. The effects of material composition, ODS particle size, and bombarding particle on the irradiation creep compliance was studied and results are compared to literature data. Evolution of microstructure during helium implantation was investigated in detail by TEM and is discussed with respect to irradiation creep models.

  20. Irradiation of goods

    International Nuclear Information System (INIS)

    Huebner, G.

    1992-01-01

    The necessary dose and the dosage limits to be observed depend on the kind of product and the purpose of irradiation. Product density and density distribution, product dimensions, but also packaging, transport and storage conditions are specific parameters influencing the conditions of irradiation. The kind of irradiation plant - electron accelerator or gamma plant - , its capacity, transport system and geometric arrangement of the radiation field are factors influencing the irradiation conditions as well. This is exemplified by the irradiation of 3 different products, onions, deep-frozen chicken and high-protein feed. Feasibilities and limits of the irradiation technology are demonstrated. (orig.) [de

  1. PIE Report on the KOMO-3 Irradiation Test Fuels

    International Nuclear Information System (INIS)

    Park, Jong Man; Ryu, H. J.; Yang, J. H.

    2009-04-01

    In the KOMO-3, in-reactor irradiation test had been performed for 12 kinds of dispersed U-Mo fuel rods, a multi wire fuel rod and a tube fuel rod. In this report we described the PIE results on the KOMO-3 irradiation test fuels. The interaction layer thickness between fuel particle and matrix could be reduced by using a large size U-Mo fuel particle or introducing Al-Si matrix or adding the third element in the U-Mo particle. Monolithic fuel rod of multi-wire or tube fuel was also effective in reducing the interaction layer thickness

  2. Facts about food irradiation: Food irradiation costs

    International Nuclear Information System (INIS)

    1991-01-01

    This fact sheet gives the cost of a typical food irradiation facility (US $1 million to US $3 million) and of the food irradiation process (US $10-15 per tonne for low-dose applications; US $100-250 per tonne for high-dose applications). These treatments also bring consumer benefits in terms of availability, storage life and improved hygiene. 2 refs

  3. Particle detectors

    CERN Document Server

    Hilke, Hans Jürgen; Joram, Christian; CERN. Geneva

    1991-01-01

    Lecture 5: Detector characteristics: ALEPH Experiment cut through the devices and events - Discuss the principles of the main techniques applied to particle detection ( including front-end electronics), the construction and performance of some of the devices presently in operartion and a few ideas on the future performance. Lecture 4-pt. b Following the Scintillators. Lecture 4-pt. a : Scintillators - Used for: -Timing (TOF, Trigger) - Energy Measurement (Calorimeters) - Tracking (Fibres) Basic scintillation processes- Inorganic Scintillators - Organic Scintil - Discuss the principles of the main techniques applied to particle detection ( including front-end electronics), the construction and performance of some of the devices presently in operation and a fiew ideas on future developpement session 3 - part. b Following Calorimeters lecture 3-pt. a Calorimeters - determine energy E by total absorption of charged or neutral particles - fraction of E is transformed into measurable quantities - try to acheive sig...

  4. Stable particles

    International Nuclear Information System (INIS)

    Samios, N.P.

    1993-01-01

    I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets. with a few more additions -- with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers-exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the forte of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc

  5. Food irradiation in China

    International Nuclear Information System (INIS)

    Zhu Jiang

    1994-01-01

    In this paper, the author discussed the recent situation of food irradiation in China, its history, facilities, clearance, commercialization, and with emphasis on market testing and public acceptance of irradiated food. (author)

  6. Particle physics

    CERN Document Server

    Martin, Brian R

    2017-01-01

    An accessible and carefully structured introduction to Particle Physics, including important coverage of the Higgs Boson and recent progress in neutrino physics. Fourth edition of this successful title in the Manchester Physics series. Includes information on recent key discoveries including : An account of the discovery of exotic hadrons, beyond the simple quark model; Expanded treatments of neutrino physics and CP violation in B-decays; An updated account of ‘physics beyond the standard model’, including the interaction of particle physics with cosmology; Additional problems in all chapters, with solutions to selected problems available on the book’s website; Advanced material appears in optional starred sections.

  7. Dosimetry for Crystals Irradiation

    CERN Document Server

    Lecomte, Pierre

    2005-01-01

    Before shipment to CMS, all PbWO4 crystals produced in China are irradiated there with 60 Co , in order to insure that the induced absorption coefficient is within specifications. Acceptance tests at CERNand at ENEA also include irradiation with gamma rays from 60 Co sources. There were initially discrepancies in quoted doses and doserates as well as in induced absorption coefficients. The present work resolves the discrepancies in irradiation measurements and defines common dosimetry methods for consistency checks between irradiation facilities.

  8. Irradiation and flavor

    International Nuclear Information System (INIS)

    Reineccius, G.A.

    1992-01-01

    Flavor will not be a significant factor in determining the success of irradiated foods entering the U.S. market. The initial applications will use low levels of irradiation that may well result in products with flavor superior to that of products from alternative processing techniques (thermal treatment or chemical fumigation). The success of shelf-stable foods produced via irradiation may be much more dependent upon our ability to deal with the flavor aspects of high levels of irradiation

  9. Food irradiation makes progress

    International Nuclear Information System (INIS)

    Kooij, J. van

    1984-01-01

    In the past fifteen years, food irradiation processing policies and programmes have been developed both by a number of individual countries, and through projects supported by FAO, IAEA and WHO. These aim at achieving general acceptance and practical implementation of food irradiation through rigorous investigations of its wholesomeness, technological and economic feasibility, and efforts to achieve the unimpeded movement of irradiated foods in international trade. Food irradiation processing has many uses

  10. Structure and properties of UV-irradiated LLDPE and alloy of PA66 and the irradiated LLDPE

    International Nuclear Information System (INIS)

    Ran Qianping; Zou Hua; Wu Shishan; Shen Jian

    2006-01-01

    Some oxygen-containing groups such as C=O, C-O and -OH were introduced onto linear low-density polyethylene (LLDPE) chains by UV irradiation in air. Their concentration increased with the irradiation time. Crystal shape of the irradiated LLDPE remained an orthorhombic structure, while space of the crystalline plane kept unchanged. The melting temperature and crystallinity decreased due to the LLDPE chain scission into small molecules compound and crystalline defects caused by UV irradiation. Compared with pristine LLDPE, hydrophilicity of the irradiated LLDPE increased due to the introduction of polar oxygen-containing groups, but the tensile strength decreased due to the LLDPE chain degradation and reduction of crystallinity. The temperature of initial weight loss of the irradiated LLDPE was lower than that of pristine LLDPE. An alloy of PA66 and the irradiated LLDPE (irradiated PA66/LLDPE) was prepared by melting blend at 260-270 degree C. Compared to non-irradiated PA66/LLDPE alloy, dispersion of LLDPE particles in the irradiated PA66/LLDPE alloy and interfacial interactions between the components were markedly improved. Therefore, tensile strength and impact strength of the irradiated PA66/ LLDPE were higher than those of the control. (authors)

  11. Containers in food irradiation

    International Nuclear Information System (INIS)

    Bolumen, S.; Espinosa, R.

    1997-01-01

    The preservation of food by irradiation is promising technology which increases industrial application. Packaging of irradiated foods is an integral part of the process. Judicious selection of the package material for successful trade is essential. In this paper is presented a brief review of important aspects of packaging in food irradiation [es

  12. Performance of irradiated silicon microstrip detectors

    International Nuclear Information System (INIS)

    Catacchini, E.; Civinini, C.; D'Alessandro, R.; Focardi, E.; Lenzi, M.; Meschini, M.; Parrini, G.; Pieri, M.

    1999-01-01

    Silicon microstrip devices to be installed in Large Hadron Collider (LHC) tracking detectors will have to operate in a high radiation environment. We report on performance studies of silicon microstrip detectors irradiated with neutrons or protons, up to fluences comparable to the first ten years of running at LHC. Obtained results show that irradiated detectors can still be operated with satisfactory signal-to-noise ratio,and in the case of inhomogeneously type inverted detector a very good position resolution is achieved regardless of the zone crossed by the particle

  13. Neutron irradiation of bacteriophage λ

    International Nuclear Information System (INIS)

    Bozin, D.; Milosevic, M. . E-mail address of corresponding author: bozinde@vin.bg.ac.yu

    2005-01-01

    Double strand breaks (DSB) are the most dangerous lesions in DNA caused by irradiation, but many other lesions, usually called mutations, have not been clearly identified. These lesions, like DSB, can be the source of serious chromosomal damages and finally - cell death. Growing interest in heavy particles for radiotherapy and radioprotection encourages the search of the molecular basis of their action. In this respect, we chose bacteriophage λ1390 as the model system for the study of consequences of neutron irradiation. This derivative of λ phage possesses an unique ability to reversibly reorganize their genome in response to various selective pressures. The phages were irradiated with 13 Gy of mixed neutrons (7.5 Gy from fast and 5.6 Gy from thermal neutrons) and phages genomes were tested to DSB and mutations. Additionally, the stability of λ capsid proteins were tested. After all tests, we can conclude that, under our conditions, low flux of neutrons does not induce neither DNA strand break or DNA mutation nor the stability of λ capsid proteins. (author)

  14. Elementary particles

    International Nuclear Information System (INIS)

    Prasad, R.

    1984-01-01

    Two previous monographs report on investigations into the extent to which a unified field theory can satisfactorily describe physical reality. The first, Unified field Theory, showed that the paths within a non-Riemannian space are governed by eigenvalue equations. The second, Fundamental Constants, show that the field tensors satisfy sets of differential equations with solutions which represent the evolution of the fields along the paths of the space. The results from the first two monographs are used in this one to make progress on the theory of elementary particles. The five chapters are as follows - Quantum mechanics, gravitation and electromagnetism are aspects of the Unified theory; the fields inside the particle; the quadratic and linear theories; the calculation of the eigenvalues and elementary particles as stable configurations of interacting fields. It is shown that it is possible to construct an internal structure theory for elementary particles. The theory lies within the framework of Einstein's programme-to identify physical reality with a specified geometrical structure. (U.K.)

  15. Pinpointing particles

    International Nuclear Information System (INIS)

    Miller, David J.

    1987-01-01

    The Conference on Position-Sensitive Detectors held at London's University College from 7-11 September highlighted the importance and the growing applications of these precision devices in many branches of science, underlining once again the high spinoff potential for techniques developed inside particle physics

  16. Particle tracking

    International Nuclear Information System (INIS)

    Mais, H.; Ripken, G.; Wrulich, A.; Schmidt, F.

    1986-02-01

    After a brief description of typical applications of particle tracking in storage rings and after a short discussion of some limitations and problems related with tracking we summarize some concepts and methods developed in the qualitative theory of dynamical systems. We show how these concepts can be applied to the proton ring HERA. (orig.)

  17. Pinpointing particles

    Energy Technology Data Exchange (ETDEWEB)

    Miller, David J.

    1987-10-15

    The Conference on Position-Sensitive Detectors held at London's University College from 7-11 September highlighted the importance and the growing applications of these precision devices in many branches of science, underlining once again the high spinoff potential for techniques developed inside particle physics.

  18. Particle Physics

    CERN Multimedia

    2005-01-01

    While biomedicine and geoscience use grids to bring together many different sub-disciplines, particle physicists use grid computing to increase computing power and storage resources, and to access and analyze vast amounts of data collected from detectors at the world's most powerful accelerators (1 page)

  19. Decomposition of Atmospheric Aerosol Phase Function by Particle Size and Morphology via Single Particle Scattering Measurements

    Science.gov (United States)

    Aptowicz, K. B.; Pan, Y.; Martin, S.; Fernandez, E.; Chang, R.; Pinnick, R. G.

    2013-12-01

    We report upon an experimental approach that provides insight into how particle size and shape affect the scattering phase function of atmospheric aerosol particles. Central to our approach is the design of an apparatus that measures the forward and backward scattering hemispheres (scattering patterns) of individual atmospheric aerosol particles in the coarse mode range. The size and shape of each particle is discerned from the corresponding scattering pattern. In particular, autocorrelation analysis is used to differentiate between spherical and non-spherical particles, the calculated asphericity factor is used to characterize the morphology of non-spherical particles, and the integrated irradiance is used for particle sizing. We found the fraction of spherical particles decays exponentially with particle size, decreasing from 11% for particles on the order of 1 micrometer to less than 1% for particles over 5 micrometer. The average phase functions of subpopulations of particles, grouped by size and morphology, are determined by averaging their corresponding scattering patterns. The phase functions of spherical and non-spherical atmospheric particles are shown to diverge with increasing size. In addition, the phase function of non-spherical particles is found to vary little as a function of the asphericity factor.

  20. Stress analysis of aspherical coated particle with inner pressure

    Energy Technology Data Exchange (ETDEWEB)

    Liu Bing, E-mail: bingliu@tsinghua.edu.cn [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China); Yang Lin; Liang Tongxiang; Tang Chunhe [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China)

    2012-10-15

    Coated particles used in HTR fuel element sustain the inner pressure during irradiation as a pressure vessel. In actually the coated particle is not real spherical but with some asphericity, the stress distribution in the vessel is not uniform, coated layer in aspherical particle sustain more additional stress due to the asphericity. In this paper, the geometric shape distribution is summarized based on actual coated particle statistic. A mechanical analysis model is proposed for SiC layer by geometric combinations, and stress distribution of coated particle with a flat is calculated. The results show that the local maximum stress of aspherical particle increased two times than that of ideal spherical coated particle, which increase the failure probability under irradiation and high temperature.

  1. Thermoluminescent and impedimetric studies on irradiated foodstuffs

    International Nuclear Information System (INIS)

    Mamoon, A.M.

    2000-01-01

    Several brands of different spices and milk powders were irradiated with relatively high doses of gamma radiation. Glow curves were produced upon heating these irradiated foodstuffs only. Study of the obtained spices glow curves revealed that the magnitude of these curves depends upon the dose received while the shape of the curves remains generally the same for the different doses and for the different spices. Previous studies had shown that the obtained thermoluminescence (TL) is due to dust particles carried by the spices. The TL studies show, furthermore, that different brands of the same spice are apparently contaminated with different amounts of dust or soil. The obtained TL from irradiated milk powders is apparently due to its mineral content. Different milk powders gave TL curves of different magnitudes for the same dose depending upon the milk brand. Impedimetric studies carried out irradiated potatoes show changes in impedance amplitude and phase angle. The results support earlier work on the use of TL to differentiate between irradiated and control foodstuffs, to assess the extent of spices contamination with soil-which perhaps reflects hygienic care-and that impedimetric measurements can distinguish irradiated from control potatoes

  2. Irradiation of foodstuffs

    International Nuclear Information System (INIS)

    Sjoeberg, A.M.

    1993-01-01

    Foodstuffs are irradiated to make them keep better. The ionizing radiation is not so strong as to cause radioactivity in the foodstuffs. At least so far, irradiation has not gained acceptance among consumers, although it has been shown to be a completely safe method of preservation. Irradiation causes only slight chemical changes in food. What irradiation does, however, is to damage living organisms, such as bacteria, DNA and proteins, thereby making the food keep longer. Irradiation can be detected from the food afterwards; thus it can be controlled effectively. (orig.)

  3. Biological effects of heavy particles

    International Nuclear Information System (INIS)

    Sabatier, L.; Martins, B.; Dutrillaux, B.

    1991-01-01

    The usual definitions of biological dose and biological dosimetry do not fit in case of particles with high linear energy transfer (LET). The dose corresponds to an average value which is not representative of the highly localized energy transfer due to heavy ions. Fortunately, up to now, a biological dosimetry following an exposure to high LET particles is necessary only for cosmonauts. In radiotherapy applications, one exactly knows the nature and energy of incident particle beams. The quality requirements for a good biodosimeter include reliable relation between dose and effect, weak sensitivity to individual variations, reliability and stability of acquired informations against the time delay between exposure and measurements. Nothing is better than the human lymphocyte to be used for measurements that fulfil these requirements. In the case of a manned spaceship, the irradiation dose corresponds to a wide range of radiation (protons, neutrons, heavy ions), and making a dosimetry as well as defining it are of current concern. As yet, there exist two possible definitions, which reduce the dose either to a proton or to a neutron equivalent one. However, such an approximation is not a faithful representation of the irradiation effects and in particular, the long-term effects may be quite different. In the future, it is reasonable to expect an evolution towards technics that enable identifying irradiated cells and quantifying precisely their radiation damage in order to reconstruct the spectrum of particles received by a given cosmonaut in a given time. Let us emphasize that the radiation hazards due to a short stay in space are quite minor, but in the case of a travel to Mars, they cannot be neglected [fr

  4. Detection of food irradiation with luminescence methods

    International Nuclear Information System (INIS)

    Anderle, H.

    1997-06-01

    Food irradiation is applied as method for the preservation of foods, the prevention of food spoilage and the inhibition of food-borne pathogens. Doses exceeding 10 kGy (10 kJ/kg) are not recommended by the WHO. The different legislation requires methods for the detection and the closimetry of irradiated foods. Among the physical methods based on the radiation-induced changes in inorganic, nonhygroscopic crystalline solids are thermoluminescence (TL), photostimulated luminescence (PSL) and lyoluminescence (LL) measurement. The luminescence methods were tested on natural minerals. Pure quartz, feldspars, calcite, aragonite and dolomite of known origin were irradiated, read out and analyzed to determine the influence of luminescence-activators and deactivators. Carbonate minerals show an orange-red TL easily detectable by blue-sensitive photomultiplier tubes. TIL-inactive carbonate samples may be identified by a lyoluminescence method using the reaction of trapped irradiation-generated charge carriers with the solvent during crystal-lattice breakup. The fine-ground mineral is dissolved in an alkaline complexing agent/chemiluminescence sensitizer/chemiluminescence catalyst (EDTA/luminol/hemin) reagent mixture. The TL and PSL of quartz is too weak to contribute a significant part for the corresponding signals in polymineral dust. Alkali and soda feldspar show intense TL and PSL. The temperature maxima in the TL glow curves allow a clear distinction. PSL does not give this additional information, it suffers from bleaching by ambient light and requires light-protection. Grain disinfestated with low irradiation doses (500 Gy) may not identified by both TL and PSL measurement. The natural TL of feldspar particles may be overlap with the irradiation-induced TL of other minerals. As a routine method, irradiated spices are identified with TL measurement. The dust particles have to be enriched by heavy-liquid flotation and centrifugation. The PSL method allows a clear

  5. Particle track membranes with higher porosity

    International Nuclear Information System (INIS)

    Heinrich, B.; Gemende, B.; Lueck, H.B.

    1992-01-01

    Possibilities of improvement of flux and dirt loading capacity of particle track membranes have been examined. Three different ways were investigated: using a divergent ion beam for the irradiation; enlarging the surface porosity through a conical pore shape; creating an asymmetrical membrane structure with two different porosities. Mathematical models and experimental results have been discussed. 9 figs, 3 tabs

  6. Study of irradiation damage structures in austenitic stainless steels

    International Nuclear Information System (INIS)

    Hamada, Shozo

    1997-08-01

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

  7. Study of irradiation damage structures in austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-08-01

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

  8. Active particles

    CERN Document Server

    Degond, Pierre; Tadmor, Eitan

    2017-01-01

    This volume collects ten surveys on the modeling, simulation, and applications of active particles using methods ranging from mathematical kinetic theory to nonequilibrium statistical mechanics. The contributing authors are leading experts working in this challenging field, and each of their chapters provides a review of the most recent results in their areas and looks ahead to future research directions. The approaches to studying active matter are presented here from many different perspectives, such as individual-based models, evolutionary games, Brownian motion, and continuum theories, as well as various combinations of these. Applications covered include biological network formation and network theory; opinion formation and social systems; control theory of sparse systems; theory and applications of mean field games; population learning; dynamics of flocking systems; vehicular traffic flow; and stochastic particles and mean field approximation. Mathematicians and other members of the scientific commu...

  9. Evaluate an impact of incident alpha particle and gamma ray on human blood components: A comparison study

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Asaad H.; Yaba, Sardar P.; Ismail, Haider J. [Medical Physics Research Group, Physics Department, Education College, Salahaddin University-Erbil, Iraqi Kurdistan (Iraq)

    2015-07-01

    An impact of alpha and gamma irradiation on human blood components have been evaluated and compared for healthy blood samples (male and females). Irradiation dose and time of irradiation calibrated and considered as a main comparison factors. Density of blood components measured for each in vitro irradiation before and after irradiation for males and females. Survey radiation dosimeter (Inspector Exp) and nuclear track detectors type CR-39 used to evaluate exposure dose rate and incident density of alpha particles, respectively. Experiment results verified that the irradiation of blood makes ionizing of blood components, either alpha or gamma irradiation dose, and the impacts of ionizing radiation were relativity for WBC, RBC, and PLT. Limited irradiation doses of 1-5 μSv/hr considered as a low radiation dose of alpha and gamma radiation sources ({sup 226}Ra, and {sup 137}Cs). Density of alpha particles accumulated on the blood surface was 34 (alpha particle/cm{sup 2}) for selected dose of incident alpha particle. Optimum value of irradiation dose and time of irradiation were 5 μSv/hr and 4 second for males and females. On the other hands, the values of irradiation dose and time of irradiation were 2.1 μSv/hr and 2 second for males and females for gamma irradiation. Thus, present results demonstrated that densities of RBC and WBC cells are capable of inducing reproduction in vitro for both type of irradiation. (authors)

  10. Evaluate an impact of incident alpha particle and gamma ray on human blood components: A comparison study

    International Nuclear Information System (INIS)

    Ismail, Asaad H.; Yaba, Sardar P.; Ismail, Haider J.

    2015-01-01

    An impact of alpha and gamma irradiation on human blood components have been evaluated and compared for healthy blood samples (male and females). Irradiation dose and time of irradiation calibrated and considered as a main comparison factors. Density of blood components measured for each in vitro irradiation before and after irradiation for males and females. Survey radiation dosimeter (Inspector Exp) and nuclear track detectors type CR-39 used to evaluate exposure dose rate and incident density of alpha particles, respectively. Experiment results verified that the irradiation of blood makes ionizing of blood components, either alpha or gamma irradiation dose, and the impacts of ionizing radiation were relativity for WBC, RBC, and PLT. Limited irradiation doses of 1-5 μSv/hr considered as a low radiation dose of alpha and gamma radiation sources ( 226 Ra, and 137 Cs). Density of alpha particles accumulated on the blood surface was 34 (alpha particle/cm 2 ) for selected dose of incident alpha particle. Optimum value of irradiation dose and time of irradiation were 5 μSv/hr and 4 second for males and females. On the other hands, the values of irradiation dose and time of irradiation were 2.1 μSv/hr and 2 second for males and females for gamma irradiation. Thus, present results demonstrated that densities of RBC and WBC cells are capable of inducing reproduction in vitro for both type of irradiation. (authors)

  11. Quick photo-Fenton degradation of phenolic compounds by Cu/Al2O3-MCM-41 under visible light irradiation: small particle size, stabilization of copper, easy reducibility of Cu and visible light active material.

    Science.gov (United States)

    Pradhan, Amaresh C; Nanda, Binita; Parida, K M; Das, Mira

    2013-01-14

    The present study reports the photo-Fenton degradation of phenolic compounds (phenol, 2-chloro-4-nitrophenol and 4-chloro-2-nitrophenol) in aqueous solution using mesoporous Cu/Al(2)O(3)-MCM-41 nanocomposite as a heterogeneous photo-Fenton-like catalyst. The in situ incorporation of mesoporous Al(2)O(3) (MA) into the framework of MCM-41 (sol-gel method) forms Al(2)O(3)-MCM-41 and wetness impregnation of Cu(II) on Al(2)O(3)-MCM-41 generates mesoporous Cu/Al(2)O(3)-MCM-41 composite. The effects of pH and H(2)O(2) concentration on degradation of phenol, 2-chloro-4-nitrophenol and 4-chloro-2-nitrophenol are studied. Kinetics analysis shows that the photocatalytic degradation reaction follows a first-order rate equation. Mesoporous 5 Cu/Al(2)O(3)-MCM-41 is found to be an efficient photo-Fenton-like catalyst for the degradation of phenolic compounds. It shows nearly 100% degradation in 45 min at pH 4. The combined effect of small particle size, stabilization of Cu(2+) on the support Al(2)O(3)-MCM-41, ease reducibility of Cu(2+) and visible light activeness are the key factors for quick degradation of phenolic compounds by Cu/Al(2)O(3)-MCM-41.

  12. Hot particles

    International Nuclear Information System (INIS)

    Merwin, S.E.; Moeller, M.P.

    1989-01-01

    Nuclear Regulatory Commission (NRC) licensees are required to assess the dose to skin from a hot particle contamination event at a depth of skin of7mg/cm 2 over an area of 1 cm 2 and compare the value to the current dose limit for the skin. Although the resulting number is interesting from a comparative standpoint and can be used to predict local skin reactions, comparison of the number to existing limits based on uniform exposures is inappropriate. Most incidents that can be classified as overexposures based on this interpretation of dose actually have no effect on the health of the worker. As a result, resources are expended to reduce the likelihood that an overexposure event will occur when they could be directed toward eliminating the cause of the problem or enhancing existing programs such as contamination control. Furthermore, from a risk standpoint, this practice is not ALARA because some workers receive whole body doses in order to minimize the occurrence of hot particle skin contaminations. In this paper the authors suggest an alternative approach to controlling hot particle exposures

  13. Ecological applications of the irradiated adsorbents

    International Nuclear Information System (INIS)

    Tusseyev, T.

    2004-01-01

    Full text: In our previous works it was shown that after irradiation some adsorbents gain new interesting properties such as increasing (or decreasing) of their adsorption capacity, selectivity in relation to some gases, change of chemical bounds of gas molecules with adsorbent surface as well as other properties. We investigated a lot of adsorbents with semiconducting and dielectric properties. A high temperature superconductor was investigated also. Adsorbents were irradiated by ultraviolet (UV) and gamma - radiation, reactor (n.γ) - radiation, α-particles (E=40-50 MeV), protons ( E=30 MeV), and also He-3 ions (E-29-60 MeV). The following techniques were used: volumetric (manometrical), mass-spectrometer and IR spectroscopic methods, and also method of electronic - paramagnetic resonance (spin paramagnetic resonance) The obtained results allow to speak about creation of new adsorbents for gas purification (clearing) from harmful impurities, gas selection into components, an increasing of adsorbing surface. Thus one more advantage of the irradiated adsorbents is that they have 'memory effect', i.e. they can be used enough long time after irradiation. In laboratory conditions we built the small-sized adsorptive pump on the basis of the irradiated zeolites which are capable to work in autonomous conditions. It was found, that some of adsorbents after irradiation gain (or lose) selectivity in relation to definite gases. So, silica gel, which one in initial state does not adsorb hydrogen, after gamma irradiation it becomes active in relation to hydrogen. Some of rare earths oxides also show selectivity in relation to hydrogen and oxygen depending on a type of irradiation. Thus, it is possible to create different absorbents, depending on a solved problem, using a way or selection of adsorbents, either of radiation type and energy, as a result obtained adsorbents can be used for various ecological purposes

  14. Effect of heavy ion irradiation on thermodynamically equilibrium Zr-Excel alloy

    Science.gov (United States)

    Yu, Hongbing; Liang, Jianlie; Yao, Zhongwen; Kirk, Mark A.; Daymond, Mark R.

    2017-05-01

    The thermodynamically equilibrium state was achieved in a Zr-Sn-Nb-Mo alloy by long-term annealing at an intermediate temperature. The fcc intermetallic Zr(Mo, Nb)2 enriched with Fe was observed at the equilibrium state. In-situ 1 MeV Kr2+ heavy ion irradiation was performed in a TEM to study the stability of the intermetallic particles under irradiation and the effects of the intermetallic particle on the evolution of type dislocation loops at different temperatures from 80 to 550 °C. Chemi-STEM elemental maps were made at the same particles before and after irradiation up to 10 dpa. It was found that no elemental redistribution occurs at 200 °C and below. Selective depletion of Fe was observed from some precipitates under irradiation at higher temperatures. No change in the morphology of particles and no evidence showing a crystalline to amorphous transformation were observed at all irradiation temperatures. The formation of type dislocation loops was observed under irradiation at 80 and 200 °C, but not at 450 and 550 °C. The loops were non-uniformly distributed; a localized high density of type dislocation loops were observed near the second phase particles; we suggest that loop nucleation is favored as a result of the stress induced by the particles, rather than by elemental redistribution. The stability of the second phase particles and the formation of the type loops under heavy ion irradiation are discussed.

  15. Short-range order in irradiated diamonds

    International Nuclear Information System (INIS)

    Agafonov, S.S.; Glazkov, V.P.; Nikolaenko, V.A.; Somenkov, V.A.

    2005-01-01

    Structural changes in irradiated diamond with a change in its density were studied. Natural diamond powders with average particle size from 14-20 μm to 0.5 mm, irradiated in beryllium block of the MR reactor up to a fluence of 1.51 x 10 21 were used as samples. Using the neutron-diffraction method, it has been established that, when density in irradiated diamonds varies, a transition from a diamond-like amorphous structure to a graphite-like structure occurs. The transition occurs at a density ρ ∼ 2.7-2.9 g/cm 3 and is accompanied by a sharp change in resistivity [ru

  16. Irradiation monitoring of spices by chemiluminescence method

    International Nuclear Information System (INIS)

    Bhatti, K.A.; Khan, H.M.; Sattar, A.; Ahmad, A.

    2001-01-01

    Some spices (cumin, coriander, black pepper and red pepper), commonly used due to their specific aroma and nutritional value were studied using chemiluminescence (CL) method to test whether the food has been irradiated or not. The spices were ground to different mesh sizes and subjected to gamma ray doses of 2.5, 5.0, 7.5 and 10 Kgy. The effect of radiation doses and particle size on the CL response of irradiated and un-irradiated samples was checked using luminol and lucigenin sensitizers. The storage experiment was also performed for all spices with both the sensitizers in order to pick the suitable sensitizer for CL study. During this study Co-60 gamma ray source and Bio-orbit 1250 luminometer were used after precise calibration

  17. The biological effectiveness of antiproton irradiation

    DEFF Research Database (Denmark)

    Holzscheiter, Michael H.; Bassler, Niels; Agazaryan, Nzhde

    2006-01-01

    ever measurements of the biological effectiveness of antiprotons. Materials and methods: V79 cells were suspended in a semi-solid matrix and irradiated with 46.7 MeV antiprotons, 48 MeV protons, or 60Co c-rays. Clonogenic survival was determined as a function of depth along the particle beams. Dose...... and particle fluence response relationships were constructed from data in the plateau and Bragg peak regions of the beams and used to assess the biological effectiveness. Results: Due to uncertainties in antiproton dosimetry we defined a new term, called the biologically effective dose ratio (BEDR), which...... has a higher relative biological effectiveness (RBE). Conclusion: We have produced the first measurements of the biological consequences of antiproton irradiation. These data substantiate theoretical predictions of the biological effects of antiproton annihilation within the Bragg peak, and suggest...

  18. Preparation of super absorbent by irradiation polymerization

    International Nuclear Information System (INIS)

    Hua Fengjun; Tan Chunhong; Qian Mengping

    1995-01-01

    A kind of absorbent is prepared by gamma-rays irradiated by reversed-phase suspension polymerization. Drying particles have 1400 (g/g) absorbency in de-ionic water. Effects of reactive conditions, e.g.: dose-rate, dose, monomer concentration, degree of monomer neutralization and crosslinking agents on absorbency in de-ionic water are discussed. The cause of absorbing de-ionic water by polymer is related to its network structure and ionic equilibrium in particle. Accordingly, a suit reactive condition is chosen for preparation of hydro gel spheres

  19. Fission product released experiment of coated fuel particles

    Energy Technology Data Exchange (ETDEWEB)

    Shijiang, Xu; Bing, Yang; Chunhe, Tang; Junguo, Zhu; Jintao, Huang; Binzhong, Zhang [Inst. of Nucl. Energy Technology, Tsinghua Univ., Beijing (China); Jinghan, Luo [Inst. of Atomic Energy, Beijing (China)

    1992-01-15

    Four samples of coated fuel particles were irradiated in the Heavy-Water Research Reactor of the Institute of Atomic Energy. Each of them was divided into two groups and irradiated to the burn up of 0.394% fima and 0.788% fima in two static capsules, respectively. After irradiation and cooling, post irradiation annealing experiment was carried out, the release ratios of the fission product {sup 133}Xe and {sup 131}I were measured, they are in the order of 10{sup -6}{approx}10{sup -7}. The fission product release ratio of naked kernel was also measured under the same conditions as for the coated fuel particles, the ratio of the fission product release of the coated fuel particles and of the naked kernel was in the order of 10{sup -5}{approx}10{sup -4}.

  20. Sensory properties of irradiated foods

    International Nuclear Information System (INIS)

    Plestenjak, A.

    1997-01-01

    Food irradiation is a simple and effective preservation technique. The changes caused by irradiation depend on composition of food, on the absorbed dose, the water content and temperature during and after irradiation. In this paper the changes of food components caused by irradiation, doses for various food irradiation treatments, foods and countries where the irradiation is allowed, and sensory properties of irradiated food are reviewed

  1. Study on the irradiation swelling of U3Si2-Al dispersion fuel

    International Nuclear Information System (INIS)

    Xing Zhonghu; Ying Shihao

    2001-01-01

    The dominant modeling mechanisms on irradiation swelling of U 3 Si 2 -Al dispersion fuel are introduced. The core of dispersion fuel is looked to as micro-fuel elements of continuous matrix. The formation processes of gas bubbles in the fuel phase are described through the behavior mechanisms of fission gases. The swelling in the fuel phase causes the interaction between fuel particles and metal matrix, and the metal matrix can restrain the irradiation swelling of fuel particles. The developed code can predict irradiation-swelling values according to the parameters of fuel elements and irradiation conditions, and the predicted values are in agreement with the measured results

  2. Electron microscopy of atmospheric particles

    Science.gov (United States)

    Huang, Po-Fu

    Electron microscopy coupled with energy dispersive spectrometry (EM/EDS) is a powerful tool for single particle analysis. However, the accuracy with which atmospheric particle compositions can be quantitatively determined by EDS is often hampered by substrate-particle interactions, volatilization losses in the low pressure microscope chamber, electron beam irradiation and use of inaccurate quantitation factors. A pseudo-analytical solution was derived to calculate the temperature rise due to the dissipation of the electron energy on a particle-substrate system. Evaporative mass loss for a spherical cap-shaped sulfuric acid particle resting on a thin film supported by a TEM grid during electron beam impingement has been studied. Measured volatilization rates were found to be in very good agreement with theoretical predictions. The method proposed can also be used to estimate the vapor pressure of a species by measuring the decay of X-ray intensities. Several types of substrates were studied. We found that silver-coated silicon monoxide substrates give carbon detection limits comparable to commercially available substrates. An advantage of these substrates is that the high thermal conductivity of the silver reduces heating due to electron beam impingement. In addition, exposure of sulfuric acid samples to ammonia overnight substantially reduces sulfur loss in the electron beam. Use of size-dependent k-factors determined from particles of known compositions shows promise for improving the accuracy of atmospheric particle compositions measured by EM/EDS. Knowledge accumulated during the course of this thesis has been used to analyze atmospheric particles (Minneapolis, MN) selected by the TDMA and collected by an aerodynamic focusing impactor. 'Less' hygroscopic particles, which do not grow to any measurable extent when humidified to ~90% relative humidity, included chain agglomerates, spheres, flakes, and irregular shapes. Carbon was the predominant element detected in

  3. In-pile irradiation of rock-like oxide fuels

    International Nuclear Information System (INIS)

    Nitani, N.; Kuramoto, K.; Yamashita, T.; Nakano, Y.; Akie, H.

    2001-01-01

    Five kinds of ROX fuels were prepared and irradiated using 20% enriched U instead of Pu. Non-destructive and destructive post-irradiation examinations were carried out. FP gas release rates of the particle-dispersed type fuels and homogeneously-blended type fuels were larger than that of the Yttria-stabilized zirconia containing UO 2 single phase fuel. From results of SEM and EPMA, decomposition of the spinel was observed. The decomposition of the spinel is probably avoided by lowering the irradiation temperature, less than 1700 K. The regions suffering the irradiation damage of the particle dispersed type fuels were less than those of the homogeneously-blended type fuels. (author)

  4. In-pile irradiation of rock-like oxide fuels

    Energy Technology Data Exchange (ETDEWEB)

    Nitani, N.; Kuramoto, K.; Yamashita, T.; Nakano, Y.; Akie, H. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)

    2001-07-01

    Five kinds of ROX fuels were prepared and irradiated using 20% enriched U instead of Pu. Non-destructive and destructive post-irradiation examinations were carried out. FP gas release rates of the particle-dispersed type fuels and homogeneously-blended type fuels were larger than that of the Yttria-stabilized zirconia containing UO{sub 2} single phase fuel. From results of SEM and EPMA, decomposition of the spinel was observed. The decomposition of the spinel is probably avoided by lowering the irradiation temperature, less than 1700 K. The regions suffering the irradiation damage of the particle dispersed type fuels were less than those of the homogeneously-blended type fuels. (author)

  5. Heat Generation by Irradiated Complex Composite Nanostructures

    DEFF Research Database (Denmark)

    Ma, Haiyan; Tian, Pengfei; Pello, Josselin

    2014-01-01

    Heating of irradiated metallic e-beam generated nanostructures was quantified through direct measurements paralleled by novel model-based numerical calculations. By comparing discs, triangles, and stars we showed how particle shape and composition determines the heating. Importantly, our results...... revealed that substantial heat is generated in the titanium adhesive layer between gold and glass. Even when the Ti layer is as thin as 2 nm it absorbs as much as a 30 nm Au layer and hence should not be ignored....

  6. New particles

    Energy Technology Data Exchange (ETDEWEB)

    Khare, A.

    1980-07-01

    Current state of art in the discovery of new elementary particles is reviewed. At present, quarks and mesons are accepted as the basic constituents of matter. The charmonium model (canti-c system), and the 'open charm' are discussed. Explanations are offered for the recent discovery of the heavy lepton tau. Quark states such as the beauty and taste are also dealt with at length. The properties of the tanti-t bound system are speculated. It is concluded that the understanding of canti-c and banti-b families is facilitated by the assumption of the quarkonium model. Implications at the astrophysical level are indicated.

  7. Particle Mechanics

    CERN Document Server

    Collinson, Chris

    1995-01-01

    * Assumes no prior knowledge* Adopts a modelling approach* Numerous tutorial problems, worked examples and exercises included* Elementary topics augmented by planetary motion and rotating framesThis text provides an invaluable introduction to mechanicsm confining attention to the motion of a particle. It begins with a full discussion of the foundations of the subject within the context of mathematical modelling before covering more advanced topics including the theory of planetary orbits and the use of rotating frames of reference. Truly introductory , the style adoped is perfect for those u

  8. Irradiation - who needs it?

    International Nuclear Information System (INIS)

    Scoular, C.

    1994-01-01

    In this paper the public's attitudes to the irradiation of food to ensure it is bacteria free and to prolong shelf-life are considered. The need to label irradiated food and to educate the public about its implications are emphasised. The opinions of the large food retailers who maintain that high standards in food processing, hygiene and refrigeration eliminate the need for food irradiation are discussed. (UK)

  9. Identification of irradiated chicken

    International Nuclear Information System (INIS)

    Spiegelberg, A.; Heide, L.; Boegl, K.W.

    1990-01-01

    Frozen chicken and chicken parts were irradiated at a dose of 5 kGy with Co-60. The irradiated chicken and chicken parts were identified by determination of three radiation-induced hydrocarbons from the lipid fraction. Isolation was carried out by high-vacuum distillation with a cold-finger apparatus. The detection of the hydrocarbons was possible in all irradiated samples by gaschromatography/mass spectrometry. (orig.) [de

  10. Food irradiation - now

    International Nuclear Information System (INIS)

    Basson, R.A.

    1989-01-01

    Food irradiation technology in South Africa is about to take its rightful place next to existing food preservation methods in protecting food supplies. This is as a result of several factors, the most important of which is the decision by the Department of Health and Population Development to introduce compulsory labelling of food irradiation. The factors influencing food irradiation technology in South Africa are discussed

  11. Development of blood irradiators

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    This project is designed to improve the techniques of blood irradiation through the development of improved and portable blood irradiators. A portable blood irradiator, consisting of a vitreous carbon body and thulium-170 radiation source, was attached to dogs via a carotid-jugular shunt, and its effects on the immune system measured. The device has demonstrated both significant suppression of circulating lymphocytes and prolonged retention of skin allografts

  12. Irradiation behavior of miniature experimental uranium silicide fuel plates

    International Nuclear Information System (INIS)

    Hofman, G.L.; Neimark, L.A.; Mattas, R.F.

    1983-01-01

    Uranium silicides, because of their relatively high uranium density, were selected as candidate dispersion fuels for the higher fuel densities required in the Reduced Enrichment Research and Test Reactor (RERTR) Program. Irradiation experience with this type of fuel, however, was limited to relatively modest fission densities in the bulk from, on the order of 7 x 10 20 cm -3 , far short of the approximately 20 x 10 20 cm -3 goal established for the RERTR program. The purpose of the irradiation experiments on silicide fuels on the ORR, therefore, was to investigate the intrinsic irradiation behavior of uranium silicide as a dispersion fuel. Of particular interest was the interaction between the silicide particles and the aluminum matrix, the swelling behavior of the silicide particles, and the maximum volume fraction of silicide particles that could be contained in the aluminum matrix

  13. Simulation analysis of radiation fields inside phantoms for neutron irradiation

    International Nuclear Information System (INIS)

    Satoh, Daiki; Takahashi, Fumiaki; Endo, Akira; Ohmachi, Y.; Miyahara, N.

    2007-01-01

    Radiation fields inside phantoms have been calculated for neutron irradiation. Particle and heavy-ion transport code system PHITS was employed for the calculation. Energy and size dependences of neutron dose were analyzed using tissue equivalent spheres of different size. A voxel phantom of mouse was developed based on CT images of an 8-week-old male C3H/HeNs mouse. Deposition energy inside the mouse was calculated for 2- and 10-MeV neutron irradiation. (author)

  14. Irradiation of food

    International Nuclear Information System (INIS)

    Lindell, B.; Danielsson-Tham, M.L.; Hoel, C.

    1983-01-01

    A committee has on instructions from the swedish government made an inquiry into the possible effects on health and working environment from irradition of food. In this report, a review is presented on the known positiv and negative effects of food irradiation Costs, availabilty, shelf life and quality of irradiated food are also discussed. According to the report, the production of radiolysis products during irradiation is not easily evaluated. The health risks from irradiation of spices are estimated to be lower than the risks associated with the ethenoxid treatment presently used. (L.E.)

  15. Gamma irradiation devices

    International Nuclear Information System (INIS)

    Foeldiak, Gabor; Stenger, Vilmos.

    1983-01-01

    The main parameters and the preparation procedures of the gamma radiation sources frequently applied for irradiation purposes are discussed. In addition to 60 Co and 137 Cs sources also the nuclear power plants offer further opportunities: spent fuel elements and products of certain (n,γ) reactions can serve as irradiation sources. Laboratory scale equipments, pilot plant facilities for batch or continuous operation, continuous industrial irradiators and special multipurpose, mobile and panorama type facilities are reviewed including those in Canada, USA, India, the Soviet Union, Hungary, UK, Japan and Australia. For irradiator design the source geometry dependence of the spatial distribution of dose rates can be calculated. (V.N.)

  16. Immunocytoadherence and sublethal irradiation

    International Nuclear Information System (INIS)

    Beaumariage, M.L.; Hiesche, K.; Revesz, L.; Haot, J.

    1975-01-01

    In sublethally irradiated CBA mice, the relative and absolute numbers of spontaneous rosette forming cells against sheep erythrocytes are markedly decreased in bone marrow. The decrease of the absolute number of spontaneous RFC is also important in the spleen in spite of an increase of the RFC relative number above the normal values between the 8th and 12th day after irradiation. The graft of normal bone marrow cells immediately after irradiation or the shielding of a medullary area during irradiation promotes the recovery of the immunocytoadherence capacity of the bone marrow cells but not of the spleen cells [fr

  17. Fluorescence of irradiated hydrocarbons

    International Nuclear Information System (INIS)

    Gulis, I.G.; Evdokimenko, V.M.; Lapkovskij, M.P.; Petrov, P.T.; Gulis, I.M.; Markevich, S.V.

    1977-01-01

    A visible fluorescence has been found out in γ-irradiated aqueous of carbohydrates. Two bands have been distinguished in fluorescence spectra of the irradiated solution of dextran: a short-wave band lambdasub(max)=140 nm (where lambda is a wave length) at lambdasub(β)=380 nm and a long-wave band with lambdasub(max)=540 nm at lambdasub(β)=430 nm. A similar form of the spectrum has been obtained for irradiated solutions of starch, amylopectin, lowmolecular glucose. It has been concluded that a macromolecule of polysaccharides includes fluorescent centres. A relation between fluorescence and α-oxiketon groups formed under irradiation has been pointed out

  18. Planning of irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Caha, A; Krystof, V [Vyzkumny Ustav Klinicke a Experimentalni Onkologie, Brno (Czechoslovakia)

    1979-07-01

    The principles are discussed of the planning of irradiation, ie., the use of the various methods of location of a pathological focus and the possibility of semiautomatic transmission of the obtained data on a two-dimensional or spatial model. An efficient equipment is proposed for large irradiation centres which should cooperate with smaller irradiation departments for which also a range of apparatus is proposed. Irradiation planning currently applied at the Research Institute of Clinical and Experimental Oncology in Brno is described. In conclusion, some of the construction principles of semi-automatic operation of radiotherapy departments are discussed.

  19. Food irradiation: fiction and reality

    International Nuclear Information System (INIS)

    1991-01-01

    The International Consultative Group on Food Irradiation (IGCFI), sponsored by World Health Organization (WHO), Food and Agriculture Organization (FAO) and the International Atomic Energy Agency (IAEA), with the intention to provide to governments, especially those of developing countries, scientifically correct information about food irradiation, decided to organize a file and questions of general public interest. The document is composed by descriptive files related with the actual situation and future prospective, technical and scientific terms, food irradiation and the radioactivity, chemical transformations in irradiated food, genetic studies, microbiological safety of irradiated food, irradiation and harmlessness, irradiation and additives, packing, irradiation facilities control, process control, irradiation costs and benefits as well as consumers reaction

  20. From particle physics to medical applications

    CERN Document Server

    Dosanjh, Manjit

    2017-01-01

    CERN is the world's largest particle physics research laboratory. Since it was established in 1954, it has made an outstanding contribution to our understanding of the fundamental particles and their interactions, and also to the technologies needed to analyse their properties and behaviour. The experimental challenges have pushed the performance of particle accelerators and detectors to the limits of our technical capabilities, and these groundbreaking technologies can also have a significant impact in applications beyond particle physics. In particular, the detectors developed for particle physics have led to improved techniques for medical imaging, while accelerator technologies lie at the heart of the irradiation methods that are widely used for treating cancer. Indeed, many important diagnostic and therapeutic techniques used by healthcare professionals are based either on basic physics principles or the technologies developed to carry out physics research. Ever since the discovery of x-rays by Roentgen...

  1. Review of recent irradiation-creep results

    International Nuclear Information System (INIS)

    Coghlan, W.A.

    1982-05-01

    Materials deform faster under stress in the presence of irradiation by a process known as irradiation creep. This phenomenon is important to reactor design and has been the subject of a large number of experimental and theoretical investigations. The purpose of this work is to review the recent experimental results to obtain a summary of these results and to determine those research areas that require additional information. The investigations have been classified into four subgroups based on the different experimental methods used. These four are: (1) irradiation creep using stress relaxation methods, (2) creep measurements using pressurized tubes, (3) irradiation creep from constant applied load, and (4) irradiation creep experiments using accelerated particles. The similarity and the differences of the results from these methods are discussed and a summary of important results and suggested areas for research is presented. In brief, the important results relate to the dependence of creep on swelling, temperature, stress state and alloying additions. In each of these areas new results have been presented and new questions have arisen which require further research to answer. 65 references

  2. Influence of Irradiation Time on properties of CdS Nanoparticles Synthesized using Microwave Irradiation

    International Nuclear Information System (INIS)

    Nayereh Soltani; Elias SSaion; Maryam Erfani; Mohd Zobir Hussein; Robiah Yunus

    2011-01-01

    Different sizes of cadmium sulfide nanoparticles which exhibit obvious quantum confinement effect have been synthesized of cadmium chloride and thioacetamide through the simple and rapid microwave method. The properties of these CdS nanoparticles were examined with varying irradiation time from 10 to 40 min using a pulse regime. The obtained CdS particles were characterized by X-ray diffraction (XRD), transition electron microscopy (TEM) and UV-visible (UV-Vis) spectroscopy. The effects of irradiation time on the size, degree of crystallinity, yield of reaction and optical band gap of CdS nanoparticles are investigated. (author)

  3. Facts about food irradiation: Chemical changes in irradiated foods

    International Nuclear Information System (INIS)

    1991-01-01

    This fact sheet addresses the safety of irradiated food. The irradiation process produces very little chemical change in food, and laboratory experiments have shown no harmful effects in animals fed with irradiated milk powder. 3 refs

  4. Modelling property changes in graphite irradiated at changing irradiation temperature

    CSIR Research Space (South Africa)

    Kok, S

    2011-01-01

    Full Text Available A new method is proposed to predict the irradiation induced property changes in nuclear; graphite, including the effect of a change in irradiation temperature. The currently used method; to account for changes in irradiation temperature, the scaled...

  5. Development of Coated Particle Fuel Technology

    International Nuclear Information System (INIS)

    Cho, Moon Sung; Kim, B. G.; Kim, Y. K.

    2009-04-01

    UO 2 kernel fabrication technology was developed at the lab sacle(20∼30g-UO 2 /batch). The GSP technique, modified method of sol-gel process, was used in the preparation of spherical ADU gel particle and these particles were converted to UO 3 and UO 2 phases in calcination furnace and sintering furnace respectively. Based on the process variables optimized using simulant kernels in 1-2 inch beds, SiC TRISO-coated particles were fabricated using UO 2 kernel. Power densities of TRISO coated particle fuels and gamma heat of the tubes are calculated as functions of vertical location of the fuel specimen in the irradiation holes by using core physics codes, MCNP and Helios. A finite model was developed for the calculations of temperatures and stresses of the specimen and the irradiation tubes. Dimensions of the test tubes are determined based on the temperatures and stresses as well as the gamma heat generated at the given condition. 9 modules of the COPA code (MECH, FAIL, TEMTR, TEMBL, TEMPEB, FPREL, MPRO, BURN, ABAQ), the MECH, FAIL, TEMTR, TEMBL, TEMPEB, and FPREL were developed. The COPA-FPREL was verified through IAEA CRP-6 accident benchmarking problems. KAERI participated in the round robin test of IAEA CRP-6 program to characterize the diameter, sphericity, coating thickness, density and anisotropy of coated particles provided by Korea, USA and South Africa. The inspection and test plan describing specifications and inspection method of coated particles was developed to confirm the quality standard of coated particles. The quality inspection instructions were developed for the inspection of coated particles by particle size analyzer, density inspection of coating layers by density gradient column, coating thickness inspection by X-ray, and inspection of optical anistropy factor of PyC layer. The quality control system for the TRISO-coated particle fuel was derived based on the status of quality control systems of other countries

  6. Performance of irradiated CVD diamond micro-strip sensors

    International Nuclear Information System (INIS)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; Mac Lynne, L.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Pan, L.S.; Pernicka, M.; Peitz, A.; Perera, L.; Pirollo, S.; Procario, M.; Riester, J.L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Wetstein, M.; White, C.; Zeuner, W.; Zoeller, M.; Plano, R.; Somalwar, S.V.; Thomson, G.B.

    2002-01-01

    CVD diamond detectors are of interest for charged particle detection and tracking due to their high radiation tolerance. In this article, we present, for the first time, beam test results from recently manufactured CVD diamond strip detectors and their behavior under low doses of electrons from a β-source and the performance before and after intense (>10 15 /cm 2 ) proton- and pion-irradiations. We find that low dose irradiation increase the signal-to-noise ratio (pumping of the signal) and slightly deteriorate the spatial resolution. Intense irradiation with protons 2.2x10 15 p/cm 2 lowers the signal-to-noise ratio slightly. Intense irradiation with pions 2.9x10 15 π/cm 2 lowers the signal-to-noise ratio more. The spatial resolution of the diamond sensors improves after irradiations

  7. Performance of irradiated CVD diamond micro-strip sensors

    Energy Technology Data Exchange (ETDEWEB)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D' Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; Mac Lynne, L.; Manfredotti, C.; Meier, D. E-mail: dirk.meier@cern.ch; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Pan, L.S.; Pernicka, M.; Peitz, A.; Perera, L.; Pirollo, S.; Procario, M.; Riester, J.L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Wetstein, M.; White, C.; Zeuner, W.; Zoeller, M.; Plano, R.; Somalwar, S.V.; Thomson, G.B

    2002-01-11

    CVD diamond detectors are of interest for charged particle detection and tracking due to their high radiation tolerance. In this article, we present, for the first time, beam test results from recently manufactured CVD diamond strip detectors and their behavior under low doses of electrons from a {beta}-source and the performance before and after intense (>10{sup 15}/cm{sup 2}) proton- and pion-irradiations. We find that low dose irradiation increase the signal-to-noise ratio (pumping of the signal) and slightly deteriorate the spatial resolution. Intense irradiation with protons 2.2x10{sup 15} p/cm{sup 2} lowers the signal-to-noise ratio slightly. Intense irradiation with pions 2.9x10{sup 15} {pi}/cm{sup 2} lowers the signal-to-noise ratio more. The spatial resolution of the diamond sensors improves after irradiations.

  8. Performance of irradiated CVD diamond micro-strip sensors

    CERN Document Server

    Adam, W; Bergonzo, P; Bertuccio, G; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; D'Angelo, P; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Hallewell, G D; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Kass, R; Koeth, T W; Krammer, Manfred; Lo Giudice, A; Lü, R; MacLynne, L; Manfredotti, C; Meier, D; Mishina, M; Moroni, L; Noomen, J; Oh, A; Pan, L S; Pernicka, Manfred; Peitz, A; Perera, L P; Pirollo, S; Procario, M; Riester, J L; Roe, S; Rousseau, L; Rudge, A; Russ, J; Sala, S; Sampietro, M; Schnetzer, S R; Sciortino, S; Stelzer, H; Stone, R; Suter, B; Tapper, R J; Tesarek, R J; Trischuk, W; Tromson, D; Vittone, E; Walsh, A M; Wedenig, R; Weilhammer, Peter; Wetstein, M; White, C; Zeuner, W; Zöller, M

    2002-01-01

    CVD diamond detectors are of interest for charged particle detection and tracking due to their high radiation tolerance. In this article we present, for the first time, beam test results from recently manufactured CVD diamond strip detectors and their behavior under low doses of electrons from a $\\beta$-source and the performance before and after intense ($>10^{15}/{\\rm cm^2}$) proton- and pion-irradiations. We find that low dose irradiations increase the signal-to-noise ratio (pumping of the signal) and slightly deteriorate the spatial resolution. Intense irradiations with protons ($2.2\\times 10^{15}~p/{\\rm cm^2}$) lowers the signal-to-noise ratio slightly. Intense irradiation with pions ($2.9\\times 10^{15}~\\pi/{\\rm cm^2}$) lowers the signal-to-noise ratio more. The spatial resolution of the diamond sensors improves after irradiations.

  9. Performance of irradiated CVD diamond micro-strip sensors

    Science.gov (United States)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; van Eijk, B.; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K. K.; Gheeraert, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; mac Lynne, L.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Pan, L. S.; Pernicka, M.; Peitz, A.; Perera, L.; Pirollo, S.; Procario, M.; Riester, J. L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R. J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Walsh, A. M.; Wedenig, R.; Weilhammer, P.; Wetstein, M.; White, C.; Zeuner, W.; Zoeller, M.; Plano, R.; Somalwar, S. V.; Thomson, G. B.

    2002-01-01

    CVD diamond detectors are of interest for charged particle detection and tracking due to their high radiation tolerance. In this article, we present, for the first time, beam test results from recently manufactured CVD diamond strip detectors and their behavior under low doses of electrons from a β-source and the performance before and after intense (>10 15/cm 2) proton- and pion-irradiations. We find that low dose irradiation increase the signal-to-noise ratio (pumping of the signal) and slightly deteriorate the spatial resolution. Intense irradiation with protons 2.2×10 15 p/ cm2 lowers the signal-to-noise ratio slightly. Intense irradiation with pions 2.9×10 15 π/ cm2 lowers the signal-to-noise ratio more. The spatial resolution of the diamond sensors improves after irradiations.

  10. Irradiation tests of THTR fuel elements in the DRAGON reactor (irradiation experiment DR-K3)

    International Nuclear Information System (INIS)

    Burck, W.; Duwe, R.; Groos, E.; Mueller, H.

    1977-03-01

    Within the scope of the program 'Development of Spherical Fuel Elements for HTR', similar fuel elements (f.e.) have been irradiated in the DRAGON reactor. The f.e. were fabricated by NUKEM and were to be tested under HTR conditions to scrutinize their employability in the THTR. The fuel was in the form of coated particles moulded into A3 matrix. The kernels of the particles were made of mixed oxide of uranium and thorium with an U 235 enrichment of 90%. One aim of the post irradiation examination was the investigation of irradiation induced changes of mechanical properties (dimensional stability and elastic behaviour) and of the corrosion behaviour which were compared with the properties determined with unirradiated f.e. The measurement of the fission gas release in annealing tests and ceramografic examinations exhibited no damage of the coated particles. The measured concentration distribution of fission metals led to conclusions about their release. All results showed, that neither the coated particles nor the integral fuel spheres experienced any significant changes that could impair their utilization in the THTR. (orig./UA) [de

  11. Composite fuel behaviour under and after irradiation

    International Nuclear Information System (INIS)

    Dehaudt, P.; Mocellin, A.; Eminet, G.; Caillot, L.; Delette, G.; Bauer, M.; Viallard, I.

    1997-01-01

    Two kinds of composite fuels have been irradiated in the SILOE reactor. They are made of UO 2 particles dispersed in a molybdenum metallic (CERMET) or a MgAl 2 O 4 ceramic (CERCER) matrix. The irradiation conditions have allowed to reach a 50000 MWd/t U burn-up in these composite fuels after a hundred equivalent full power days long irradiation. The irradiation is controlled by a continuous measure of the pellet centre line temperature. It allows to have information about the TANOX rods thermal behaviour and the fuels thermal conductivities in comparing the centre line temperature versus linear power curves among themselves. Our results show that the CERMET centre line temperature is much lower than the CERCER and UO 2 ones: 520 deg. C against 980 deg. C at a 300W/cm linear power. After pin puncturing tests the rods are dismantled to recover each fuel pellet. In the CERCER case, the cladding peeling off has revealed that the fuel came into contact with the cladding and that some of the pellets were linked together. Optical microscopy observations show a changing of the MgAl 2 O 4 matrix state around the UO 2 particles at the pellets periphery. This transformation may have caused a swelling and would be at the origin of the pellet-cladding and the pellet-pellet interactions. No specific damage is seen after irradiation. The CERMET pellets are not cracked and remain as they were before irradiation. The CERCER crack network is slightly different from that observed in UO 2 . Kr retention was evaluated by annealing tests under vacuum at 1580 deg. C or 1700 deg. C for 30 minutes. The CERMET fission gas release is lower than the CERCER one. Inter- and intragranular fission gas bubbles are observed in the UO 2 particles after heat treatments. The CERCER pellet periphery has also cracked and the matrix has transformed again around UO 2 particles to present a granular and porous aspect. (author). 4 refs, 6 figs, 2 tabs

  12. Performance of silicon pad detectors after mixed irradiations with neutrons and fast charged hadrons

    Energy Technology Data Exchange (ETDEWEB)

    Kramberger, G. [Jozef Stefan Institute, Department of Physics, University of Ljubljana, Jamova 39, SI-1000 Ljubljana (Slovenia)], E-mail: Gregor.Kramberger@ijs.si; Cindro, V.; Dolenc, I.; Mandic, I.; Mikuz, M.; Zavrtanik, M. [Jozef Stefan Institute, Department of Physics, University of Ljubljana, Jamova 39, SI-1000 Ljubljana (Slovenia)

    2009-10-11

    A large set of silicon pad detectors produced on MCz and FZ wafer of p- and n-type was irradiated in two steps, first by fast charged hadrons followed by reactor neutrons. In this way the irradiations resemble the real irradiation fields at LHC. After irradiations controlled annealing started in steps during which the evolution of full depletion voltage, leakage current and charge collection efficiency was monitored. The damage introduced by different irradiation particles was found to be additive. The most striking consequence of that is a decrease of the full depletion voltage for n-type MCz detectors after additional neutron irradiation. This confirms that effective donors introduced by charged hadron irradiation are compensated by acceptors from neutron irradiation.

  13. Performance of silicon pad detectors after mixed irradiations with neutrons and fast charged hadrons

    International Nuclear Information System (INIS)

    Kramberger, G.; Cindro, V.; Dolenc, I.; Mandic, I.; Mikuz, M.; Zavrtanik, M.

    2009-01-01

    A large set of silicon pad detectors produced on MCz and FZ wafer of p- and n-type was irradiated in two steps, first by fast charged hadrons followed by reactor neutrons. In this way the irradiations resemble the real irradiation fields at LHC. After irradiations controlled annealing started in steps during which the evolution of full depletion voltage, leakage current and charge collection efficiency was monitored. The damage introduced by different irradiation particles was found to be additive. The most striking consequence of that is a decrease of the full depletion voltage for n-type MCz detectors after additional neutron irradiation. This confirms that effective donors introduced by charged hadron irradiation are compensated by acceptors from neutron irradiation.

  14. Fermilab | Particle Physics Division

    Science.gov (United States)

    Diversity Education Safety Sustainability and Environment Contact Science Science Particle Physics Neutrinos Scientific Computing Research & Development Key Discoveries Benefits of Particle Physics Particle Superconducting Test Accelerator LHC and Future Accelerators Accelerators for Science and Society Particle Physics

  15. Organelle-specific injury to melanin-containing cells in human skin by pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, G.F.; Shepard, R.S.; Paul, B.S.; Menkes, A.; Anderson, R.R.; Parrish, J.A.

    1983-12-01

    Physical models predict that ultraviolet laser radiation of appropriately brief pulses can selectively alter melanin-containing cellular targets in human skin. Skin of normal human volunteers was exposed to brief (20 nanosecond) 351-nm wave length pulses from a XeF excimer laser, predicting that those cells containing the greatest quantities of melanized melanosomes (lower half of the epidermis) would be selectively damaged. Transmission electron microscopy revealed the earliest cellular alteration to be immediate disruption of melanosomes, both within melanocytes and basal keratinocytes. This disruption was dose dependent and culminated in striking degenerative changes in these cells. Superficial keratinocytes and Langerhans cells were not affected. It was concluded that the XeF excimer laser is capable of organelle-specific injury to melanosomes. These findings may have important clinical implications in the treatment of both benign and malignant pigmented lesions by laser radiations of defined wave lengths and pulse durations.

  16. Laser ablation of nanoscale particles with 193 nm light

    International Nuclear Information System (INIS)

    Choi, J H; Lucas, D; Koshland, C P

    2007-01-01

    Laser interaction with nanoscale particles is distinct and different from laser-bulk material interaction, where a hot plasma is normally created. Here, we review our studies on 193 nm laser ablation of various nanoscale particles including NaCl, soot, polystyrene, and gold. The 20 ns laser beam with fluences up to 0.3 J/cm 2 irradiates nanoparticles in a gas stream at laser repetition rates from 10 to 100 Hz. The particle size distributions before and after irradiation are measured with a scanning mobility particle sizer (SMPS), and particle morphology is examined with electron microscopy. All the nanomaterials studied exhibit a similar disintegration pattern and similar particle formation characteristics. No broadband emission associated with particle heating or optical breakdown is observed. The nanoparticles formed after irradiation have a smaller mean diameter and an order of magnitude higher number concentration with a more spherical shape compared to the original particles. We use the photon-atom ratio (PAR) to interpret the laser-particle interaction energetics

  17. Irradiation of foodstuffs

    International Nuclear Information System (INIS)

    Bugyaki, L.

    1977-01-01

    The author studies the criteria for the harmlessness of irradiation as a food-preservation process. The glucose and proteins of bacto-tryptone, irradiated at 5 Mrads, do not increase the Escherichia Coli C 600 lysogenous bacteriophages, compared to the induction produced by direct irradiation of the strain or to the exposition to nitrogenous yperite. The possible mutagenic effect is therefore different. Wheat flour freshly irradiated at 5 Mrads shows physico-chemical changes. When given to mice as 50% of their ration, it leads to a higher incidence of tumours and a greater number of meiotic chromosome alteration (besides some discreet physio-pathological changes in fertility and longevity). Immunoelectrophoresis in agar or agarose gel does not allow any detection of irradiation of meat, fish or eggs. A vertical electrophoresis in starch gel can lead to a differentiation between frozen or chilled meat and the one that is irradiated at 0.5 or 5 Mrads, but the same thing can't be said for fish or eggs. Lastly an irradiated mushroom shows every sign of freshness but, when planted in a suitable medium, its cuttings do not present any cell proliferation which could give a rapid and simple method of detecting the irradiation. (G.C.)

  18. Materials modified by irradiation

    International Nuclear Information System (INIS)

    Chmielewski, A.G.

    2007-01-01

    Application of radiation in pharmaceutical sciences and cosmetology, polymer materials, food industry, environment, health camre products and packing production is described. Nano-technology is described more detailed, because it is less known as irradiation using technology. Economic influence of the irradiation on the materials value addition is shown

  19. Special irradiation techniques

    International Nuclear Information System (INIS)

    Colomez, Gerard; Veyrat, J.F.

    1981-01-01

    Irradiation trials conducted on materials-testing reactors should provide a better understanding of the phenomena which characterize the working and evolution in time of electricity-generating nuclear reactors. The authors begin by outlining the objectives behind experimental irradiation (applied to the various nuclear chains) and then describe the special techniques deployed to achieve these objectives [fr

  20. Food irradiation: the facts

    International Nuclear Information System (INIS)

    Webb, Tony; Lang, Tim

    1987-01-01

    The London Food Commission summarizes its concerns about the use of food irradiation in the U.K. resulting from its working group surveys of general public opinion, trading standard officers and the food industry in the U.K., and from experience in countries already permitting irradiation to a variety of foods. (U.K.)

  1. Progress in food irradiation

    Energy Technology Data Exchange (ETDEWEB)

    1982-01-01

    The volume contains reports from 19 countries on the state of the project in the field of food irradiation (fruit, vegetables, meat, spices) by means of gamma rays. The tests ran up to 1982. Microbiological radiosensitivity and mutagenicity tests provide a yard stick for irradiation efficiency.

  2. Food irradiation: the facts

    International Nuclear Information System (INIS)

    Hamilton, M.

    1990-01-01

    The author explains in simple question and answer form what is entailed in the irradiation of food and attempts to dispel some of the anxieties surrounding the process. Benefits and limitations, controls, labelling safety, and tests for the detection of the use irradiation in food preparation are some of the topics dealt with in outline. (author)

  3. Perspective on food irradiation

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    Recent US Food and Drug Administration approval of irradiation treatment for fruit, vegetables and pork has stimulated considerable discussion in the popular press on the safety and efficacy of irradiation processing of food. This perspective is designed to summarize the current scientific information available on this issue

  4. Food Irradiation in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Kawabata, T.

    1981-09-15

    Since 1967 research activities on food irradiation in Japan have been carried out under the National Food Irradiation Programme by the Japanese Atomic Energy Commission. The programme has been concentrated on the technological and economical feasibility and wholesomeness testings of seven irradiated food items of economic importance to the country, i.e. potatoes, onions, wheat, rice, 'kamaboko' (fish-paste products), 'Vienna' sausages and mandarin oranges. By now most studies, including wholesomeness testings of these irradiated food items, have been completed. In Japan, all foods or food additives for sale are regulated by the Food Sanitation Law enforced in 1947. Based on studies made by the national programme, irradiated potatoes were given 'unconditional acceptance' for human consumption in 1972. At present, irradiated potatoes are the only food item which has so far been approved by the Minister of Health and Welfare. Unless the Minister of Health and Welfare has declared that items are not harmful to human health on obtaining comments from the Food Sanitation Investigation Council, no irradiated food can be processed or sold. In addition, the import of irradiated foodstuffs other than potatoes from foreign countries is prohibited by law.

  5. Post irradiation conical keratosis

    International Nuclear Information System (INIS)

    Vestey, J.P.; Hunter, J.A.A.; Mallet, R.B.; Rodger, A.

    1989-01-01

    The authors have recently seen 3 patients affected by a widespread eruption of minute keratoses confined to areas of irradiated skin with clinical and histologial features of which they have been unable to find previous literary descriptions. A fourth patient with similar clinical and histopathological features occurring after exposure only to actinic irradiation is described. (author)

  6. Post irradiation conical keratosis

    Energy Technology Data Exchange (ETDEWEB)

    Vestey, J.P.; Hunter, J.A.A. (Royal Infirmary, Edinburgh (UK)); Mallet, R.B. (Westminster Hospital, London (UK)); Rodger, A. (Western General Hospital, Edinburgh (UK))

    1989-03-01

    The authors have recently seen 3 patients affected by a widespread eruption of minute keratoses confined to areas of irradiated skin with clinical and histologial features of which they have been unable to find previous literary descriptions. A fourth patient with similar clinical and histopathological features occurring after exposure only to actinic irradiation is described. (author).

  7. Irradiation damage in superconductors

    International Nuclear Information System (INIS)

    Quere, Y.

    1989-01-01

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

  8. Food preservation by irradiation

    International Nuclear Information System (INIS)

    Labots, H.; Huis in 't Veld, G.J.P.; Verrips, C.T.

    1985-01-01

    After a review of several methods for the preservation of food and the routes of food infections, the following chapters are devoted to the preservation by irradiation. Applications and legal aspects of food irradiation are described. Special reference is made to the international situation. (Auth.)

  9. Food irradiation control

    International Nuclear Information System (INIS)

    Ley, F.J.

    1988-01-01

    A brief review is given of the control and monitoring of food irradiation with particular emphasis on the UK situation. After describing legal aspects, various applications of food irradiation in different countries are listed. Other topics discussed include code of practice for general control for both gamma radiation and electron beam facilities, dose specification, depth dose distribution and dosimetry. (U.K.)

  10. Uniformly irradiated polymer film

    International Nuclear Information System (INIS)

    Fowler, S.L.

    1979-01-01

    Irradiated film having substantial uniformity in the radiation dosage profile is produced by irradiating the film within a trough having lateral deflection blocks disposed adjacent the film edges for deflecting electrons toward the surface of the trough bottom for further deflecting the electrons toward the film edge

  11. Studies on the preservation of food by gamma irradiation

    International Nuclear Information System (INIS)

    Kim, S.K.; Umeda, K.

    1979-01-01

    This work was conducted to investigate the effects of ionizing radiation on the preservation of potato. The Irish Cobbler potato tubers were irradiated at the doses of 7 krad and 15 krad of gamma ray of Co-60 at room temperature. When the potato tubers were stored under various conditions, the freshness and preservability of irradiated potato tubers were remarkably extended by 20, June. The results of this work are summarized as follows: The potato tubers applied with 15 krad of gamma ray were observed freshness without any shrinkage and defects. The potato tubers of control rotted and sprouted completely on 3, March. All tubers of them were cured at 7 0 C and relative humidity of 90% for a month before irradiation and they were treated at 18-20 0 C and RH 80% for 2 weeks after irradiation. They were stored at the above mentioned conditions. Reducing Sugar content of irradiated potato tubers was negligibly changed such as non-irradiated potato tubers along with an extended storage period, when they, as pre-and post-irradiation, were stored at 7 0 C and RH 90%. If they were treated at 18-20 0 C and RH 80% for 2 weeks after irradiation, reducing sugar content of the potato tubers was temporarily increased and then it was decreased as much as the former. As the result of microscopic test for the wound-peridom formation of potato tubers, the dark brown cork layer of wounded tuber of control was perfectly built up at about 2 weeks of the post wound, and starch particles have disappeared almost. The cork layer of irradiated potato tuber was formed at 3-4 weeks after wounded and also starch particles were not watched. The layers irradiated potato was observed the same as cork layer of sound potato. (author)

  12. Irradiation temperature dependence of defect formation of nitrides (A1N and c-BN) during neutron irradiations

    International Nuclear Information System (INIS)

    Atobe, Kozo.; Okada, Moritami; Nakagawa, Masuo

    2000-01-01

    The nitrogen vacancy concentration in the more refractory nitrides (A1N and c-BN) is determined as a function of reactor fluence up to 5.2x10 17 thermal neutrons/cm 2 and a function of the irradiation temperature at 25, 50, 100, 150, 200, 250 K. It is found that there is no remarkable dependence of the defect formation in nitrides on the irradiation temperature. The production of damage in the nitrides is considerably different from that in oxides. From the irradiation experiments using thermal neutron irradiation field, it is suggested in reactor irradiation that the atomic displacements in the nitrides occur predominately from energetic particles of the nuclear reactions with thermal neutrons in addition to the elastic collisions by fast neutron

  13. Irradiation Creep in Graphite

    Energy Technology Data Exchange (ETDEWEB)

    Ubic, Rick; Butt, Darryl; Windes, William

    2014-03-13

    An understanding of the underlying mechanisms of irradiation creep in graphite material is required to correctly interpret experimental data, explain micromechanical modeling results, and predict whole-core behavior. This project will focus on experimental microscopic data to demonstrate the mechanism of irradiation creep. High-resolution transmission electron microscopy should be able to image both the dislocations in graphite and the irradiation-induced interstitial clusters that pin those dislocations. The team will first prepare and characterize nanoscale samples of virgin nuclear graphite in a transmission electron microscope. Additional samples will be irradiated to varying degrees at the Advanced Test Reactor (ATR) facility and similarly characterized. Researchers will record microstructures and crystal defects and suggest a mechanism for irradiation creep based on the results. In addition, the purchase of a tensile holder for a transmission electron microscope will allow, for the first time, in situ observation of creep behavior on the microstructure and crystallographic defects.

  14. Irradiation of goods

    International Nuclear Information System (INIS)

    Lunt, R.E.

    1987-01-01

    Mechanical handling apparatus is adapted to handle goods, such as boxed fruit, during a process of irradiation, in palletized form. Palletized goods are loaded onto wheeled vehicles in a loading zone. Four vehicles are wheeled on a track into an irradiation zone via a door in a concrete shield. The vehicles are arranged in orthogonal relationship around a source of square section. Turntables are positioned at corners of the square shaped rail truck around the source selectively to turn the vehicles to align then with track sections. Mechanical manipulating devices are positioned in the track sections opposed to sides of the source. During irradiation, the vehicles and their palletized goods are cylically moved toward the source to offer first sides of the goods for irradiation and are retraced from the source and are pivoted through 90 0 to persent succeeding sides of the goods for irradiation

  15. Irradiation of packaged food

    International Nuclear Information System (INIS)

    Kilcast, D.

    1990-01-01

    Food irradiation is used to improve the safety of food by killing insects and microorganisms, to inhibit sprouting in crops such as onions and potatoes and to control ripening in agricultural produce. In order to prevent re-infestation and re-contamination it is essential that the food is suitably packed. Consequently, the packaging material is irradiated whilst in contact with the food, and it is important that the material is resistant to radiation-induced changes. In this paper the nature of the irradiation process is reviewed briefly, together with the known effects of irradiation on packaging materials and their implications for the effective application of food irradiation. Recent research carried out at the Leatherhead Food RA on the possibility of taint transfer into food is described. (author)

  16. Issues in food irradiation

    International Nuclear Information System (INIS)

    Mills, S.

    1987-04-01

    This discussion paper has two goals: first, to raise public awareness of food irradiation, an emerging technology in which Canada has the potential to build a new industry, mainly oriented to promising overseas markets; and second, to help build consensus among government and private sector decision makers about what has to be done to realize the domestic and export potential. The following pages discuss the potential of food irradiation; indicate how food is irradiated; outline the uses of food irradiation; examine questions of the safety of the equipment and both the safety and nutritional value of irradiated food; look at international commercial developments; assess the current and emerging domestic scene; and finally, draw some conclusions and offer suggestions for action

  17. Extracorporeal irradiation -Physicist perspective

    International Nuclear Information System (INIS)

    Vijayaprabhu, N.; Saravanan, K.S.; Gunaseelan; Vivekanandam, S.; Reddy, K.S.; Parthasarathy; Mourougan, S.; Elangovan, K.

    2008-01-01

    Extracorporeal irradiation (ECI) involves irradiation of body tissues, particularly malignant bones of the extremities, outside the body. This involves en bloc resection of the tumour, extracorporeal irradiation of the bone segment with a single dose of 50 Gy or more, and reimplantation of the irradiated bone with fixation devices. Bone tumours like Ewing's Sarcoma, Chondrosarcoma and Oesteosarcoma; in the involved sites like femur, tibia, humerus, ilium and sacrum can be treated with ECI. The reimplanted bone simply acts as a framework for appositional bone growth from surrounding healthy bones. The conventional indications for postoperative irradiation are still applied. The major advantages of ECI are the precise anatomic fit of the reimplanted bone segment, preservation of joint mobility and its potential in avoiding the growth discrepancy commonly seen in prosthetic replacement. The use of ECI was first described in 1968 and practiced in Australia since 1996. In our center, we have completed six ECIs

  18. Structure modification of particle track membranes

    International Nuclear Information System (INIS)

    Lueck, H.B.; Gemende, B.; Heinrich, B.

    1991-01-01

    Three different structure modifications were studied in order to improve the flux and dirt loading capacity of particle track membranes without affecting their retention characteristic. Divergent irradiation is a very effective tool for decreasing the number of multiple pores and increasing the porosity up to 20 per cent. The technique leads to a remarkable but not efficient enhancement of the surface porosity. Improved surface porosity produced by a double irradiation technique turns out to be very effective with respect to the filtration performance. (author)

  19. Effect of {alpha}-Particle and X-Ray Irradiation on DNA Synthesis in Tissue Cultures; Effet de l'Irradiation par les Particules a et par les Rayons X sur la Synthese de l'ADN dans des Cultures de Tissus; 0412 043b 0438 044f 0414 ; Efectos de la Irradiacion con Particulas Alfa y con Rayos X sobre la Sintesis de ADN en Cultivos de Tejidos

    Energy Technology Data Exchange (ETDEWEB)

    Smith, C. L. [Department of Radiotherapeutics, University of Cambridge, Cambridge (United Kingdom)

    1962-02-15

    The effect of both a-particle and X-ray irradiation on the rate of DNA synthesis in mouse fibroblast and HeLa cells in tissue culture is described. Tritiated thymidine micro autoradiography was used to indicate the rate of synthesis in the single layer cultures used. The results of the experiments show that: (1) The fraction of cells in a culture synthesizing DNA is unaffected by {alpha}-particles and X-rays in the doses used in the experiment. (2) The effect of either type of radiation is to reduce the rate of synthesis of DNA of the irradiated cells in synthesis. (3) The effect of a given dose of either type of radiation is to reduce the rate of synthesis of all the cells to a constant fraction of what it was in the unirradiated cells. (4) The rate of DNA synthesis is reduced to 37% (1/e) by a dose of ca. 25 {alpha}/{mu}{sup 2} or an X-ray dose of 14000 rad for mouse fibroblast cultures. In Hela cell cultures a dose of ca. 90000 rad is needed to reduce the rate of DNA synthesis to 37% of the initial value. (5) The reduction in synthesis occurs not more than a half hour after irradiation and may be an immediate effect. From (4) above the target shape can be roughly calculated and if it is assumed to be cylindrical it appears to have dimensions ca. 16 A in one direction and 16 000 A in the other, i. e. a long thin thread with a MW of ca. 5 * 10{sup 7} in the case of the mouse fibroblast experiments. In the case of the Hela cell experiments the target volume gives a MW of ca. 10{sup 7}. The results are consistent with the view that the target may possibly be the DNA template (or maybe DNAP because of the high MW in one case). If the effects described reflect damage to the DNA (or DNAP) template during the exponential phase of synthesis then observations (1), (2) and (3) above follow as obvious correlatives. (author) [French] L'auteur expose l'effet de l'irradiation par les particules {alpha} et par les rayons X sur la vitesse de synthese de l'ADN au niveau du

  20. Effect of 60Co γ-irradiation on saccharification of uncooked sweet potato material

    International Nuclear Information System (INIS)

    Hu Tingchun; Xiong Xingyao; Yi Jinqiong; Wang Keqin; Su Xiaojun; Zou Jianfeng

    2010-01-01

    Using the starch and powder of sweet potato of Xiangshu 86 and Xiangshu 541 as materials, the effect of 60 Co γ-irradiation on the structure of starch particle and the efficiency of saccharification were studied. The result showed that some reticulate flaws appeared in the surface of irradiated starch particles, and the reticulate flaws were increased with the increase of irradiation dose. The content of reducing sugar and total soluble sugar in both starch and the powder were obviously increased along with the increase of irradiation dose ranged from 50 to 1200 kGy. The saccharification efficiency of Xiangshu 86 and Xiangshu 541 was obviously difference at the dose lower than 500 kGy, and then the efficiency showed the similar trends at higher dose irradiation, the saccharification rate reached the highest value after the treatment of 1200 kGy irradiation. (authors)