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Sample records for gamma-ray irradiated elastomer

  1. Detecting onset of chain scission and crosslinking of gamma-ray irradiated elastomer surfaces using frictional force microscopy

    CERN Document Server

    Banerjee, S; Gayathri, N; Ponraju, D; Dash, S; Tyagi, A K; Raj, B; Raj, Baldev

    2005-01-01

    We report here that atomic force microscope (AFM) in frictional force mode can be used to detect onset of chain scission and crosslinking in polymeric and macromolecular samples upon irradiation. A systematic investigation to detect chain scission and crosslinking of two elastomers: (1) Ethylene-propylene-diene monomer rubber (EPDM) and (2) Fluorocarbon rubber (FKM) upon gamma-ray irradiation has been carried out using frictional force microscopy (FFM). From the AFM results we observed that both the elastomers show a systematic smoothening of its surfaces, as the gamma-ray dose rate increases. However, the frictional property studied using FFM of the sample surfaces show an initial increase and then a decrease as a function of dose rate. This behavior of increase in its frictional property has been attributed to the onset of chain scission and the subsequent decrease in friction has been attributed to the onset of crosslinking of the polymer chains. The evaluated qualitative and semi-quantitative changes obse...

  2. Inactivation of citrus tristeza virus by gamma ray irradiation

    International Nuclear Information System (INIS)

    The total exposure of gamma ray and the intensity of gamma ray per hour for the inactivation of citrus tristeza virus (CTV) and also the effect on citrus tissues are described. The budwoods of Morita navel orange infected with a severe seedling-yellow strain of CTV were irradiated with gamma ray from a 60Co source for 20 -- 52 hours. The buds or small tissue pieces of the irradiated budwoods were subsequently grafted onto Mexcan lime. CTV was easily inactivated by the irradiation from 10 to 18 kR for from 20 to 52 hours. The higher the total exposure, the higher the rate of inactivation. The CTV in the budwoods was almost inactivated after the irradiation with 20 kR. When the total exposure to gamma ray on budwoods was the same, CTV was more efficiently inactivated by the irradiation for long period with low intensity of gamma ray per hour than that for short period with high intensity per hour. Gamma ray irradiation was effective to eliminate CTV from citrus tissues. (Mori, K.)

  3. Inactivation of citrus tristeza virus by gamma ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ieki, Hiroyuki; Yamaguchi, Akira

    1984-12-01

    The total exposure of gamma ray and the intensity of gamma ray per hour for the inactivation of citrus tristeza virus (CTV) and also the effect on citrus tissues are described. The budwoods of Morita navel orange infected with a severe seedling-yellow strain of CTV were irradiated with gamma ray from a /sup 60/Co source for 20 - 52 hours. The buds or small tissue pieces of the irradiated budwoods were subsequently grafted onto Mexcan lime. CTV was easily inactivated by the irradiation from 10 to 18 kR for from 20 to 52 hours. The higher the total exposure, the higher the rate of inactivation. The CTV in the budwoods was almost inactivated after the irradiation with 20 kR. When the total exposure to gamma ray on budwoods was the same, CTV was more efficiently inactivated by the irradiation for long period with low intensity of gamma ray per hour than that for short period with high intensity per hour. Gamma ray irradiation was effective to eliminate CTV from citrus tissues. (Mori, K.).

  4. Thermal decomposition of ammonium perchlorate during gamma-ray irradiation

    International Nuclear Information System (INIS)

    To assess radiation damage effects in propellants, pyrotechnics, and similar materials, thermal decomposition measurements were made on ammonium perchlorate powders and crystals during gamma-ray irradiation. Gas evolution studies were made on single crystals and powders of ammonium perchlorate, both at room temperature and at 2270C. The results are discussed. (U.S.)

  5. Influence of gamma ray irradiation on metakaolin based sodium geopolymer

    Energy Technology Data Exchange (ETDEWEB)

    Lambertin, D., E-mail: david.lambertin@cea.fr [CEA, DEN, DTCD/SPDE/LP2C, F-30207 Bagnols-sur-Cèze (France); Boher, C. [CEA, DEN, DTCD/SPDE/LP2C, F-30207 Bagnols-sur-Cèze (France); Dannoux-Papin, A. [CEA, DEN, DTCD/SPDE/LCFI, F-30207 Bagnols-sur-Cèze (France); Galliez, K.; Rooses, A.; Frizon, F. [CEA, DEN, DTCD/SPDE/LP2C, F-30207 Bagnols-sur-Cèze (France)

    2013-11-15

    Effects of gamma irradiation on metakaolin based Na-geopolymer have been investigated by external irradiation. The experiments were carried out in a gamma irradiator with {sup 60}Co sources up to 1000 kGy. Various Na-geopolymer with three H{sub 2}O/Na{sub 2}O ratios have been studied in terms of hydrogen radiolytic yield. The results show that hydrogen production increases linearly with water content. Gamma irradiation effects on Na-geopolymer microstructure have been investigated with porosity measurements and X-ray pair distribution function analysis. A change of pore size distribution and a structural relaxation have been found after gamma ray irradiation.

  6. Thermoluminescence of Simulated Interstellar Matter after Gamma-ray Irradiation

    OpenAIRE

    Koike, K.; Nakagawa, M.(Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan); Koike, C.; M. Okada; 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 neu...

  7. Dosimetry for high dose rate gamma ray irradiation equipment

    International Nuclear Information System (INIS)

    The dose rate and distribution of the machine gamma ray in the title were studied at the opportunity of its move to Gamma-ray Facilities using a glass dosimeter calibrated. The machine, Gammator M M38-3 (Radiation Machinery Corp.), W 24 in. x D 24 in. x H 63 in., had a source of 88.8 TBq 137Cs to irradiate samples of 60Co gamma source. For measuring the dose rate and distribution, glass dosimeters were fixed on an acryl plate stand of 3 in. x 8 in. by arranging in 3 rows (x axis) x 7 columns (y axis), and the stand was irradiated by gamma ray for 1 min. Irradiation was performed with either rotating or resting condition of the sample turntable and each exposure dose was read out. From the dosimeters at the center of rotation, water absorbed dose D =8.465 Gy was obtained (Mar. 30, 2010). The dose distribution along y axis was found to have 2 peaks of 1.18 and 1.08 times higher than the center above. Fluctuation was high at measurement on the restuation was high at measurement on the resting turntable. As above, the distribution was not homogeneous depending on the feature of the sample, and turntable should be rotated during irradiation. The machine was operable from April, 2010. (T.T.)

  8. Apoptosis and necrosis in testes irradiated with gamma rays

    International Nuclear Information System (INIS)

    The present study focused on sub-microscopical investigation of apoptotic and necrotic cells in the testes of dogs subjected to single local irradiation with gamma rays at three different doses, 1.5 Gy, 3 Gy and 4 Gy, on days 1, 15, 30, 45, 120 and 150 after irradiation. On day 1 after irradiation, no necrotic cells were observed in the testicular tissue. The first cells in which apoptosis was observed on days 15 and 30 after irradiation with the lower dose were spermatogonia, spermatocytes and round spermatids. These cells showed morphological changes typical of apoptosis. Their depletion was observed on day 45 after irradiation and they were found in the lumen of seminiferous tubuli. Some dead cells were eliminated from seminiferous tubuli by phagocytosis by means of Sertoli cells. After irradiation with higher doses of gamma rays some cells of seminiferous epithelium showed morphological signs of apoptosis while other manifested necrosis. Sertoli cells and Leydig cells were considerably resistant to radiation. However, after irradiation with the highest dose of 4 Gy sporadic cells showed signs of apoptosis. On day 120 after irradiation the testes contained no necrotic cells and by day 150 spermiogenesis was recovered. (authors)

  9. Thermoluminescence of Simulated Interstellar Matter after Gamma-ray Irradiation

    CERN Document Server

    Koike, K; 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 $10^{17}n_f{\\rm /cm^{2}}$). After irradiation, samples are stored in liquid nitrogen for several months to allow the decay of induced radioactivity. We measured the luminescence spectra of the gamma ray irradiated samples during warming to 370K using a spectrophotometer. For the forsterite and magnesite, the spectra exhibit a rather intense peak at about 645 -- 655 nm and 660 nm respectively, whereas luminescence scarcely appeared in olivine sample. The spectra of forsterite is very similar to the ERE of the Red Rectangle.

  10. Grafting study of polysulfone polymeric membranes by gamma ray irradiation

    International Nuclear Information System (INIS)

    Radiation-induced grafting of styrene poli sulfone films were investigated by simultaneous method in solution using gamma-ray from a radio nuclide 60Co source. The gamma-ray energy of high intensity induced breaking of chemical bonds leading to free radical formation. The radical start a conventional polymerization sequence comparable with that obtained with a chemical catalyst acting as initiator. The effects of grafting conditions such as irradiation total dose, dose rate and addition of cross linking agent, were studied by means of morphology analysis, thermal degradation and crystallinity. After the grafting reaction, the membranes were submitted to an exhaustive extraction with solvent to remove the polystyrene homopolymer formed. The degree of grafting (DOG) was analyzed by percentage of weight increase. As a result, the reaction always follows the same pattern: DOG increases rapidly initially whilst propagation is the main reaction, then more slowly as termination becomes more frequent. (author)

  11. Synergistic effects of neutron and gamma ray irradiation of a commercial CHMOS microcontroller

    International Nuclear Information System (INIS)

    This paper presents the experimental results of a combined irradiation environment of neutron and gamma rays on 80C196KC20, which is a 16-bit high performance member of the MCS96 microcontroller family. The electrical and functional tests were made in three irradiation environments: neutron, gamma rays, combined irradiation of neutron and gamma rays. The experimental results show that the neutron irradiation can affect the total ionizing dose behaviour. Compared with the single radiation environment, the microcontroller exhibits considerably more severe degradation in neutron and gamma ray synergistic irradiation. This phenomenon may cause a significant hardness assurance problem. (condensed matter: structure, thermal and mechanical properties)

  12. Gamma-ray irradiation of ohmic MEMS switches

    Science.gov (United States)

    Maciel, John J.; Lampen, James L.; Taylor, Edward W.

    2012-10-01

    Radio Frequency (RF) Microelectromechanical System (MEMS) switches are becoming important building blocks for a variety of military and commercial applications including switch matrices, phase shifters, electronically scanned antennas, switched filters, Automatic Test Equipment, instrumentation, cell phones and smart antennas. Low power consumption, large ratio of off-impedance to on-impedance, extreme linearity, low mass, small volume and the ability to be integrated with other electronics makes MEMS switches an attractive alternative to other mechanical and solid-state switches for a variety of space applications. Radant MEMS, Inc. has developed an electrostatically actuated broadband ohmic microswitch that has applications from DC through the microwave region. Despite the extensive earth based testing, little is known about the performance and reliability of these devices in space environments. To help fill this void, we have irradiated our commercial-off-the-shelf SPST, DC to 40 GHz MEMS switches with gamma-rays as an initial step to assessing static impact on RF performance. Results of Co-60 gamma-ray irradiation of the MEMS switches at photon energies ? 1.0 MeV to a total dose of ~ 118 krad(Si) did not show a statistically significant post-irradiation change in measured broadband, RF insertion loss, insertion phase, return loss and isolation.

  13. A commercial gamma-ray irradiation plant in Japan

    International Nuclear Information System (INIS)

    In 1973, a commercial gamma-ray irradiation plant was constructed in Takasaki, about 100 km north of Tokyo. The plant has been used for both production of irradiated commercial products and irradiation services. The irradiation services are being made available for sterilization of both medical appliances such as disposable medical syringes, catheters, surgical sutures, and sterilization of feed stuffs for animals. Treatment of plastic materials and colouring of both crystals and glass wares are also undertaken. This facility can accommodate 600 kCi of 60Co and has a monthly treating capacity of 12,000 packages ( a standard carton of 340 mm x 400 mm x 500 mm) at an irradiation dose of 1 Mrad/hr. A receiving port for packages is on the second floor and the outlet of the irradiated packages on the first floor, with three lines of connecting loop conveyors between them, and the irradiation compartment in the center section. The space arrangement of the facility is well designed and gravity can be utilized for the transportation of the packages. Polymer impregnated coral is put on the market for ornamental building material on an order contract basis. (author)

  14. Electrons versus gamma rays. Alternative sources for irradiation processes

    International Nuclear Information System (INIS)

    Energetic electrons and gamma rays are used for a variety of commercial irradiation processes such as the modification of polymeric materials, the sterilization of medical devices, the preservation of foods and the treatment of municipal and industrial wastes. The chemical and biological effects of these radiations are similar, but the differences in their physical characteristics and economics may favour one over the other for a particular application. Electron accelerators with energies under 5 MeV producing intense, high-power beams are mainly used for curing coatings and thin plastic and rubber products, while gamma-ray sources emitting diffuse radiation with substantially greater penetration are used predominantly for medical products and some agricultural commodities. The increasing demand for large gamma-ray sources and the currently limited supplies are now stimulating the development of electron accelerators of 5 to 15 MeV with more penetration that can provide an alternative to gamma sources for the treatment of packages and bulk materials. High-power bremsstrahlung (X-ray) generators can also be considered for applications requiring still greater penetration. Where either electrons or photons can provide satisfactory dose distributions within the products, the productivity of accelerators and gamma sources can be compared on the basis of available power and utilization efficiency. For example, a 10 MeV, 20 kW machine would be equivalent to 2 MCi of 6060Co, assuming 50% and 35% power utilization, respectively. The price of such an accelerator might be comparable to that of a 60Co source, while at twice this power level, the accelerator would be substantially less expensive than 60Co. Operating and maintenance costs for a 40 kW machine would also be less than the cost of gamma source replenishment in a 4 MCi facility. High-power accelerators are also justifiable for smaller facilities since their higher capital cost can be compensated for by a reduction in operating cost due to a shorter work schedule. (author)

  15. Gamma-ray spectroscopy on irradiated MTR fuel elements

    International Nuclear Information System (INIS)

    The availability of burnup data is an important requirement in any systematic approach to the enhancement of safety, economics and performance of a nuclear research reactor. This work presents the theory and experimental techniques applied to determine, by means of nondestructive gamma-ray spectroscopy, the burnup of Material Testing Reactor (MTR) fuel elements irradiated in the IEA-R1 research reactor. Burnup measurements, based on analysis of spectra that result from collimation and detection of gamma-rays emitted in the decay of radioactive fission products, were performed at the reactor pool area. The measuring system consists of a high-purity germanium (HPGe) detector together with suitable fast electronics and an on-line microcomputer data acquisition module. In order to achieve absolute burnup values, the detection set (collimator tube+HPGe detector) was previously calibrated in efficiency. The obtained burnup values are compared with ones provided by reactor physics calculations, for three kinds of MTR fuel elements with different cooling times, initial enrichment grades and total number of fuel plates. Both values show good agreement within the experimental error limits

  16. Gamma ray irradiation effect on statistical distribution of threshold voltage of MOS transistors

    International Nuclear Information System (INIS)

    Effect of gamma ray irradiation on MOS transistors is attempted as threshold voltage shift which are caused by charges formation in oxide. In this paper, we are analyzed some experimental results which show gamma ray irradiation effect on statistical distribution of threshold voltage shift of MOS transistors. These results are compared with theoretically provided ones. (author)

  17. Water radiolysis in a crack tip under gamma ray irradiation

    International Nuclear Information System (INIS)

    Under a non-irradiation condition, oxidant, e.g., O2 and H2O2, in a crack tip is supplied from the bulk water. But under irradiation conditions, even if the diffusion of radiolytic species is not sufficient, direct radiolysis in the crack tip causes high concentrations of radiolytic species. As a result of measurements and Monte Carlo calculation of gamma ray energy deposition, it has been confirmed that the energy deposition rate in the gap water is larger than that in the bulk water. The energy absorption rate increases as the gap width decreases and reaches 1.3 times that in the bulk water. In order to evaluate crack propagation rate for irradiation assisted stress corrosion cracking (IASCC) of stainless steel, a water radiolysis model in a crevice is proposed. A larger energy deposition rate in the crevice water produces many more radiolytic species, which causes high oxidant concentrations in spite of enhanced recombination of the species at the crevice inner surface. So, for IASCC evaluation, crevice water chemistry plays an important role to determine the crack propagation rate under irradiation. (authors)

  18. Elimination of gamma rays from a thermal neutron field for medical and biological irradiation purposes

    International Nuclear Information System (INIS)

    When a research reactor is used as a neutron source, a considerable amount of contamination with gamma rays is unavoidable. In biological and medical uses of neutrons, the gamma rays from the reactor core become background against the thermal neutrons. The paper proposes the use of a bismuth scatterer as a gamma-ray eliminator by which a neutron field with very few gamma rays can be obtained. A lithium-fluoride tile, manufactured by the sintering method, was also found to be a good neutron collimator as it produces few gamma rays while absorbing neutrons. The boron accumulation effect in tissue was estimated for a tissue-equivalent liquid model. The importance of minimizing gamma-ray contamination in the thermal neutron field is emphasized for selective irradiation of the boron-containing tissue. The neutron field was applied to several experiments, such as biological experiments for the treatment of cancers. (author)

  19. Neutron and gamma ray irradiation to polycrystalline ceramics

    International Nuclear Information System (INIS)

    Full text of publication follows: In burning plasma experiments, fast ions (alpha particles and hydrogen ions) with MeV energies and high heat fluxes are lost from confined plasmas to first walls inside a vacuum vessel. The lost fast ions cause the degradation of plasma performance and the erosion of first walls. A diagnostic tool for fast ion losses (called a lost ion probe) is used to understand the behaviors of fast ions and their related plasma physics. The lost ion probe located near first walls/blankets can measure the pitch angle and the energy of lost fast ions from analyzing the image of their hitting locations. For visible imaging analysis, we use a phosphor made of polycrystalline ceramics. In absence of experimental characteristics of polycrystalline ceramics under high neutron and gamma ray circumferences, sintered polycrystalline ceramics of Ce:Y3Al5O12 (Ce:YAG) is studied using the experimental nuclear reactor (JRR-3) for radiation ray irradiation. The radiation damage causes the light output reduction of sintered Ce:YAG. With short-annealing time, the temperature dependence is investigated, and the light output of the damaged specimen recovers up to 80% of the original one. In addition, for the installation to thermo nuclear reactors as a diagnostic tool, ion beam irradiations are also characterized. (authors)

  20. Effect of gamma-ray irradiation on starch in sweet popato roots

    International Nuclear Information System (INIS)

    Starch contents, as well as the size and molecular weight, in sweet potato roots decreased during steerage at 30 degrees C after gamma-ray irradiation, accompanying the increase of sucrose content. No change in the starch and sucrose contents was observed in unirradiated specimens. By microscopy damaged starch granules were observed only in gamma-ray irradiated root. The results suggested that starch was converted into sucrose unirradiated sweet potato roots by the enzymes responsible for starch-sugar interconversion of which the activities were enhanced by gamma-ray irradiation

  1. Chromatographic study of gamma-ray irradiated degradation of chlorinated hydrocarbon in water

    International Nuclear Information System (INIS)

    Degradation of chlorinated hydrocarbon in gamma ray irradiation was examined in order to get information on treatment of groundwater. Water chloroform was sealed into a vial irradiated with gamma ray. Both gas chromatography and ion chromatography were applied for determination of degradation products. Carbon dioxide, carbon monoxide, methane, ethane and chloride ion were detected in the irradiated system. Effect of radiation dose on the gamma ray induced chloroform degradation was investigated. The elimination of chloride ion and the degradation of chloroform were promoted by gamma irradiation in a dose-dependent manner. The G(CHCl3), which was defined as the number of degraded chloroform molecules when absorbed 100eV, was inferred to be 3.1. The degradation mechanism of chloroform irradiated with gamma ray seemed to involve that chloroform reacted with electron from radiolysis of water and the elimination of chloride ion occurred. (author)

  2. Degradation of SiGe HBT with reactor pulse neutron and gamma rays irradiation

    International Nuclear Information System (INIS)

    The typical dc electronic parameters degradation of SiGe HBT irradiated by reactor pulse neutron and gamma rays were measured. The mechanisms of transient radiation-induced damage in SiGe HBT were preliminary analyzed

  3. Application of nondestructive gamma-ray and neutron techniques for the safeguarding of irradiated fuel materials

    International Nuclear Information System (INIS)

    Nondestructive gamma-ray and neutron techniques were used to characterize the irradiation exposures of irradiated fuel assemblies. Techniques for the rapid measurement of the axial-activity profiles of fuel assemblies have been developed using ion chambers and Be(?,n) detectors. Detailed measurements using high-resolution gamma-ray spectrometry and passive neutron techniques were correlated with operator-declared values of cooling times and burnup

  4. Effect of gamma ray irradiation on the ferroelectric and piezoelectric properties of barium stannate titanate ceramics

    International Nuclear Information System (INIS)

    Tin doped barium titanate ceramics has been obtained by solid state reaction method followed by high energy ball milling. The effect of heavy dose gamma ray irradiation on the ferroelectric and piezoelectric properties of the synthesized barium stannate titanate ceramics has been observed. It has been found that on irradiation the ferroelectric property decreases with decreasing values of Pr and Ec. The piezoelectric properties including d33, electrostrictive strain and electromechanical coupling coefficient (Kp) also decrease following the same trend of Pr and Ec. Grain size decreases and grain patterns become irregular after irradiation as observed from SEM micrographs. The Thermoluminescence (TL) property of the barium stannate titanate ceramics has also been investigated and reported. - Highlights: • Gamma ray irradiation effects have been reported. • The ferroelectric property decreases due to gamma ray irradiation. • Values of different piezoelectric constants decrease upon irradiation. • TL glow curve shows thermoluminescence property of the ceramic system

  5. Studies on the influences of. gamma. -ray irradiation upon food additives, (6). Radiolysis of monosodium glutamate due to. gamma. -ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, M. (Shimonoseki Univ. of Fisheries, Yamaguchi (Japan)); Gohya, Y.; Ishio, S.

    1981-08-01

    The effect of ..gamma..-ray irradiation on monosodium glutamate (MSG) in aqueous solution and in ''kamaboko'' was investigated to evaluate the rate of decomposition of MSG and to elucidate the safety of the decomposed products, under the concentration of 106.9 mmol/l aqueous solution and 1% content of MSG in ''kamaboko''. In aqueous solution, MSG was decomposed by ..gamma..-ray irradiation, and G value was estimated to be 1.24. The decomposition of MSG resulted from deamination reaction was estimated to be 40% of the total decomposition. Glutamic acid content decreased as the dose of ..gamma..-ray increased in MSG-enriched ''kamaboko'', while it increased as the dose of ..gamma..-ray increased in MSG-free ''kamaboko''. Glutamic acid was liberated from the protein in ''kamaboko'', therefore the apparent decomposition rate of MSG in ''kamaboko'' was regarded as lower than actual.

  6. Suppressing effect of low-dose gamma-ray irradiation on collagen-induced arthritis

    International Nuclear Information System (INIS)

    We previously reported attenuation of autoimmune disease by low-dose gamma-ray irradiation in MRL-lpr/lpr mice. Here, we studied the effect of low-dose gamma-ray irradiation on collagen-induced arthritis (CIA) in DBA/1J mice. Mice were immunized with type II collagen, and exposed to low-dose gamma-rays (0.5 Gy per week for 5 weeks). Paw swelling, redness, and bone degradation were suppressed by irradiation, which also delayed the onset of pathological change and reduced the severity of the arthritis. Production of tumor necrosis factor-alpha, interferon-gamma, and interleukin-6, which play important roles in the onset of CIA, was suppressed by the irradiation. The level of anti-type II collagen antibody, which is essential for the onset of CIA, was also lower in irradiated CIA mice. The population of plasma cells was increased in CIA mice, but irradiation blocked this increase. Since regulatory T cells are known to be involved in suppression of autoimmune disease, the population of CD4+CD25+Foxp3+ regulatory T cells was measured. Intriguingly, a significant increase of these regulatory T cells was found in irradiated CIA mice. Overall, our data suggest that low-dose gamma-ray irradiation could attenuate CIA through suppression of pro-inflammatory cytokines and autoantibody production, and induction of regulatory T cells. (author)

  7. Results on neutron and gamma-ray irradiation of electrolytic tiltmeters

    International Nuclear Information System (INIS)

    We report on irradiation studies done to a sample of high-precision electrolytic tiltmeters with gamma-rays, up to a maximum dose of 150 kGy, and neutrons, up to a maximum fluence of 1.5x1014 cm-2. The effect of the irradiation on their performance is discussed

  8. Sterilization of commercial spices by gamma-ray irradiation and its effect to essencial oil

    International Nuclear Information System (INIS)

    Eleven kinds of commercial spices were irradiated with gamma-ray at the dose of 0 to 5 kGy. The microbial counts of almost all the samples were decreased under 103/g by the dose of 5 kGy. The D10 value of microbials contaminated to these spices were 1.1 to 4.3. Five kGy of gamma-ray irradiation affected to the recoveries of essencial oil from the spices. The effect was varied between spices. While the recoveries from some spices were increased, the others were decreased. (author)

  9. Tetraploid induction by gamma-ray irradiation in mulberry

    International Nuclear Information System (INIS)

    Vigorously growing mulberry trees were exposed to 5 kR of gamma rays at the rate of 0.2 kR/h and 5 kR/h and successively pruned three times in two growing seasons. The frequency of tetraploids induced was much higher than that of mutations, though almost all of them were cytochimeras. By tracing a process of the formation of cytochimeras it is inferred that a mutation is a unicellular event, with radiation treatment on materials in a multicellular constitution such as shoot apices resulting in the formation of chimeras, periclinal and mericlinal chimeras. (author)

  10. Structural ordering of multi-walled carbon nanotubes (MWCNTs) caused by gamma (?)-ray irradiation

    Science.gov (United States)

    Silambarasan, D.; Iyakutti, K.; Asokan, K.; Vasu, V.

    2015-06-01

    Multi-walled carbon nanotubes (MWCNTs) were irradiated by Gamma (?)-rays in air with absorbed doses of 25 and 50 kGy. As a result of ?-ray irradiation, the inter-wall distance of MWCNTs was decreased and their graphitic order was improved. The reduction in inter-wall distance and structural ordering was improved with the increasing dosage of irradiation. Experimental evidences are provided by powder XRD and micro-Raman analyses.

  11. Radiation-sensitive field effect transistor response to gamma-ray irradiation

    OpenAIRE

    Pejovi? Mili? M.; Pejovi? Mom?ilo M.; Jakši? Aleksandar B.

    2011-01-01

    The influence of gate bias during gamma-ray irradiation on the threshold voltage shift of radiation sensitive p-channel MOSFETs determined on the basis of transfer characteristics in saturation has been investigated. It has been shown that for the gate bias during the irradiation of 5 V and 10 V the sensitivity of these transistors can be presented as the threshold voltage shift and the absorbed irradiation dose ratio. On the bases of the subthreshold characteristics and transfer charac...

  12. Mutation induction in Philippine bananas c.v. 'Lakatan' thru gamma ray irradiation

    International Nuclear Information System (INIS)

    Banana is the most important crop grown in the Philippines. Among the cultivars grown, 'Lakatan' is the most popular and commands a higher price in the local market. Despite high production, losses due to over ripening, bruising and short shelf life is one of the major constraints in a successful banana industry. The use of chemicals for delayed ripening however, remains an issue of concern due to economic and organic products advocacy. Thus, development and generation of new improved 'Lakatan' cultivar through gamma ray irradiation was carried out. Mutation was induced in 'Lakatan', a popular Philippine cultivar using gamma ray irradiation. Radio sensitivity was established at 50Gy. Morphological, cytological and molecular analysis done showed significant variations between the irradiated samples and the non-irradiated plants. In terms of morphological parameters, gamma ray irradiation affected leaf traits resulting to increased leaf width, leaf length, and number of leaves. Stem girth on the other hand was significantly reduced. Cytological observations showed that gamma irradiation increased the epidermal width, leaf thickness and size of stomates but reduced the number of stomates. For post harvest attributes, gamma irradiation prolonged the shelf life of banana fruits from 11 days to 14 days. Molecular analysis showed that some markers (RAPD and AFLP) were able to detect unique bands in samples irradiated with 50Gy while the SSR markers did not detect any band dithe SSR markers did not detect any band difference between the irradiated samples and the control. (author)

  13. Performance analysis of gamma-ray-irradiated color complementary metal oxide semiconductor digital image sensors

    CERN Document Server

    Kang, A G; Liu, J Q; You, Z

    2003-01-01

    The performance parameters of dark output images captured from color complementary metal oxide semiconductor (CMOS) digital image sensors before and after gamma-ray irradiation were studied. The changes of red, green and blue color parameters of dark output images with different gamma-ray doses and exposure times were analyzed with our computer software. The effect of irradiation on the response of blue color was significantly affected at a lower dose. The dark current density of the sensors increases by three orders at > 60 krad compared to that of unirradiated sensors. The maximum and minimum analog output voltages all increase with irradiation doses, and are almost the same at > 120 krad. The signal to noise ratio is 48 dB before irradiation and 35 dB after irradiation of 180 krad. The antiradiation threshold for these sensors is about 100 krad. The primary explanation for the changes and the degradation of device performance parameters is presented. (author)

  14. Modifications in the Morphology of Poly(styrene-co-divinylbenzenes) Induced by Gamma-ray Irradiation.

    Czech Academy of Sciences Publication Activity Database

    Aleksieva, Krasimira; Sassi, A.; Je?ábek, Karel

    2010-01-01

    Ro?. 70, ?. 6 (2010), s. 361-365. ISSN 1381-5148 Institutional research plan: CEZ:AV0Z40720504 Keywords : gamma-ray irradiation * specific surface area * polymer morphology Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.546, year: 2010

  15. A 60Co gamma-ray underwater irradiation test facility

    International Nuclear Information System (INIS)

    An irradiation facility with 3.7 x 1014 Bq of 60Co for textile research was constructed adopting the form of underwater irradiation and making use of used radiation sources. The facility is simple in structure, and easy to operate with low building costs. The effective irradiation space is a cylinder of ?225 x 250 mm, in which irradiation uniformities (Dmax/Dmin) range in 1.28-1.40, 1.17-1.30 and 1 respectively. It is suitable for irradiation of samples of various materials and for scientific experiments

  16. Endurance of cultured pearls irradiated with gamma-rays

    International Nuclear Information System (INIS)

    Pearls change their color to grey by ?-ray irradiation. Grey densities were determined from darkness of pearl nuclei and thickness of the pearl layers. The densities are independent of both diameters of nuclei and pearls. The fading rate increases with increasing storage temperature. The rate of fading for irradiated pearls is lower than that for natural blue pearls. Comparison of photomicrographs (x 12) for pearls irradiated and then stored at room temperature for about 6 years revealed that their surfaces are not substantially different from the surfaces of unirradiated cultured pearls, indicating that ? irradiation hardly gives rise to deterioration. ?-Ray irradiation is a technique for coloration of pearls. Irradiated blue pearls seem to have resistivity to fading and to deterioration of the surface, if pearls have been irradiated properly. (author)

  17. Coloring of cultured pearls by gamma-rays irradiation

    International Nuclear Information System (INIS)

    Changing cream pearls into bluish-grey by ? ray irradiation is a technique in coloring of pearls. Irradiated pearls are similar in color to cultured blue pearls. The pearl layers hardly change their color but the nuclei change into dark brown by irradiation. Visible light (500 - 700 nm) penetrating the pearl layer is absorbed by dark brown nucleus. The intensity of reflecting light between 400 and 500 nm at pearl surface, therefore, becomes stronger than that between 500 and 700 nm; therefore color of irradiated pearls look bluish-grey. The density of bluish-grey color increases with increasing absorbed doses, but their luster at surface diminishes owing to the deterioration of the pearl layer by prolonged irradiation; high doses irradiation should be avoided. Irradiated pearls show no substantial fading of their color in a year and the rate of the fading is found to be lower than that for cultured blue pearls. (author)

  18. Gamma-ray irradiation tests of CMOS sensors used in imaging techniques

    Directory of Open Access Journals (Sweden)

    Cappello Salvatore G.

    2014-01-01

    Full Text Available Technologically-enhanced electronic image sensors are used in various fields as diagnostic techniques in medicine or space applications. In the latter case the devices can be exposed to intense radiation fluxes over time which may impair the functioning of the same equipment. In this paper we report the results of gamma-ray irradiation tests on CMOS image sensors simulating the space radiation over a long time period. Gamma-ray irradiation tests were carried out by means of IGS-3 gamma irradiation facility of Palermo University, based on 60Co sources with different activities. To reduce the dose rate and realize a narrow gamma-ray beam, a lead-collimation system was purposely built. It permits to have dose rate values less than 10 mGy/s and to irradiate CMOS Image Sensors during operation. The total ionizing dose to CMOS image sensors was monitored in-situ, during irradiation, up to 1000 Gy and images were acquired every 25 Gy. At the end of the tests, the sensors continued to operate despite a background noise and some pixels were completely saturated. These effects, however, involve isolated pixels and therefore, should not affect the image quality.

  19. Bio metrical studies on gonads of adult ceratitis capitata (wied) following irradiation with gamma rays

    International Nuclear Information System (INIS)

    Adults of ceratitis capitata (wied.) aged from 24 to 42 hours., were irradiated with 30 and 60 Gy gamma rays. At intervals of 1, 3, 6, 8, 10, 13, 15, 17 and 20 days after irradiation, anatomical and bio metrical studies were performed to detect the extent of gonads recovery. In males, reduction in the size of the tests was recorded from the first day after irradiation, reached its maximum on the fifteenth to seventeenth day, and increased again on the seventeenth and twenty days. No complete recovery of gonads could be expected in spite of this increase. In females, observed reduction in the size of the ovaries was recorded from the first till the fifteenth day after irradiation, followed by a slight increase on the seventeenth day and ended by another decrease on the twenty day. Also, reduction in the number of ovarioles as well as atrophied ovaries were observed. No recovery of female gonads was expected. In general females are sensitive to gamma rays than males and the dose of 30 Gy gamma rays is suitable for sterilizing 24 to 42 hours. old adults. The proper time for repeating the release of sterilizing adults for controlling programmes is every two weeks after irradiation. 2 fig

  20. Functionalization of gold and carbon nanostructured materials using gamma-ray irradiation

    International Nuclear Information System (INIS)

    Gold nanoparticles were successfully attached to the surface sites of carbon nanotubes (CNT). Both nanostructured materials were functionalized by ?-ray irradiation without chemical treatments for creating active sites. UV-visible absorption spectra of the un-irradiated and gamma ray-irradiated nanomaterials are also studied. The absorption spectrum of the irradiated CNT shows a new strong peak located at 700 nm, which might act as the active site on the surface of CNT, the result being an attachment of gold nanoparticles. This approach provides an efficient method to attach other nanostructures to carbon nanotubes for using them in different applications such as medicine and synthesis of catalytic materials.

  1. Qualities of Patin Fishball Irradiated by Gamma Rays (60Co)

    International Nuclear Information System (INIS)

    An experiment on patin fishball quality using gamma irradiation (60Co) has been conducted. Samples were irradiated at 0, 1, 3 and 5 kGy and stored in refrigerator at temperature 10 oC for sixty days. Samples were analysed every fifteen days, except content of fat and protein that analysed only at the beginning and the end of storage. The purpose of this experiment is to know the quality changes of patin fishball irradiated during storage, by measuring of chemical (content of fat, protein, water, TVB value, pH value) and microbiology (TPC aerobic and anaerobic bacteria) changes. The results showed that irradiation did not affect macro nutrient contents (content of fat, protein and water) of patin fishball during storage but irradiation can affect TVB and pH values. Irradiation at 1 kGy can reduce one logarithmic cycle of total aerobic and anaerobic bacteria. The storage life of irradiated patin fishball treated at 1, 3 and 5 kGy could be extended up to 15, 30 and 60 days, respectively. Control samples the storage life could be extended less than 15 days. (author)

  2. Physico-chemical characterization of gamma rays irradiated crotamine

    International Nuclear Information System (INIS)

    Ionizing radiation can change the molecular structure and affect the biological properties of biomolecules. It has been employed to attenuate animal toxins. Crotamine, a toxin from Crotalus durissus terrificus (Cdt), is a highly basic polypeptide (pI - 10.3), with myotoxic activity and molecular weight of 4882 Da. It is composed of 42 amino acids residues and reticulated by three disulfide bonds. This study aimed the characterization of irradiated crotamine using Circular Dichroism (CD), Fluorescence Spectroscopy and Differential Scanning Calorimetry (DSC) techniques. We used size exclusion and ion-exchange chromatography to purify it from Cdt crude venom. The pure crotamine was irradiated with 2.0 kGy from a 60Co source. Native and irradiated crotamine were analyzed in a fluorescence spectrophotometer (Hitachi F-4500), under excitation wavelength at 275 nm and the emission was scanned from 300 to 500 nm. The analysis of fluorescence quenching showed that the irradiated form displayed a lower quantum yield when compared to the native form. CD spectra, obtained from a Jasco, J-180 spectropolarimeter, of native and irradiated crotamine solutions, showed a discrete change between the samples, from apparently ordered conformation to a random coil. Finally, the thermodynamics analysis, realized in a calorimeter METTLER TOLEDO, DSC 822e, showed that irradiation promoted changes in the calorimetric profile. Our results indicate that irradiation leads to progressive changes in the structure of the toxin, which could explain the decrease in myotoxic activity. (author)

  3. Low temperature gamma-ray irradiation effects on polymer materials

    International Nuclear Information System (INIS)

    The gamma radiation induced degradation of glass fiber reinforced plastic (GFRP) and polymethylmethacrylate (PMMA) at 77K was examined by flexural test and gas analysis after irradiation and compared by the irradiation at room temperature. The decrease in flexural strength at break was much less at 77K than at RT. The evolution of CH4, CO and CO2 was also depressed at 77K. The temperature dependence of the degradation closely relates to the local molecular motion of matrix resin during irradiation. Polytetrafluoroethylene (PTFE) was also studied by irradiation at RT, 77K and 4K in terms of tensile elongation and molecular weight. The degradation was much less at 77K and 4K than at RT, and the same between 77K and 4K. (author)

  4. Effect of gamma-ray and electron irradiation on the response of solid-state track detectors

    International Nuclear Information System (INIS)

    Specimens of muscovite mica were first exposed to fission fragments and then to various gamma-ray fields from a 60Co source ranging from 1.9 x 103 to 1.6 x 104 Mrad dose. The results show that the average etched width of fission-fragment tracks decreases with increasing gamma-ray dose. Shallow pits were observed in etched specimens when the gamma-ray dose exceeded 5 x 103 Mrad. Numerous shallow etch pits caused by the gamma-ray irradiation interfered with the observation of fission tracks in the specimens. No shallow etch pits were observed in the specimen annealed for 100 min at 6000C before the gamma-ray irradiation. Pre-annealing extends the ''safety limits'' of gamma background below which muscovite mica can be used to observe fission tracks without any gamma-ray interference. Gamma-ray and electron irradiation caused significant increase of the resistance to thermal decomposition of muscovite mica. The resistance increased markedly in the dose range from 5 x 103 to 8 x 103 Mrad. These phenomena suggest the use of mica to assess radiation doses of gamma rays and electrons up to several thousand megarads. (author)

  5. Accumulation efficiency of cancer stem-like cells post {gamma}-ray and proton irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Quan Yi; WangWeikang; Fu Qibin; Mei Tao; Wu Jingwen; Li Jia [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Yang, Gen, E-mail: gen.yang@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Wang Yugang [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)

    2012-09-01

    Ionizing radiation (IR) has been proven to be a powerful medical treatment in cancer therapy. Rational and effective use of its killing power depends on understanding IR-mediated responses at the molecular, cellular and tissue levels. Increasing evidence supports that cancer stem-like cells (CSCs) play an important role in tumor regrowth and spread post radiotherapy, for they are resistant to various therapy methods including radiation. Presently, SW620 colon carcinoma monolayer culture cells were irradiated with {gamma}-rays and protons of 2 Gy. Then apoptosis, clonogenic survival and the expression of CD133{sup +} protein were examined. The results showed that there was no significantly difference either on long-term clonogenic survival or on short-term apoptosis ratio. However, compared with {gamma}-rays, irradiation with protons was less efficient to accumulate CSCs at the same dose, although both protons and {gamma}-rays can significantly accumulate the CD133{sup +} CSCs subpopulation. In addition, the results of sphere formation assay also confirmed that proton irradiation is less efficient in CSCs accumulation, suggesting proton irradiation might have higher efficiency in CSCs elimination for cancer radiotherapy.

  6. Priming effect on a polycrystalline CVD diamond detector under {sup 60}Co {gamma}-rays irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Lei, E-mail: leilan1029@163.com [Northwest Institute of Nuclear Technology, P.O. Box 69-9, Xi' an 710024 (China); Xiaoping, Ouyang [Northwest Institute of Nuclear Technology, P.O. Box 69-9, Xi' an 710024 (China); Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); School of Nuclear Science and Technology, Xi' an Jiaotong University, Xi' an 710049 (China); Xinjian, Tan; Liangbin, Xia; Na, Cao [Northwest Institute of Nuclear Technology, P.O. Box 69-9, Xi' an 710024 (China); Bing, Liu [School of Nuclear Science and Engineering, North China Electric Power University, Beijing 102206 (China); Xiaodong, Zhang [Northwest Institute of Nuclear Technology, P.O. Box 69-9, Xi' an 710024 (China)

    2012-04-21

    The priming effect on a polycrystalline chemical vapor deposition (CVD) diamond film detector caused by irradiation with {sup 60}Co {gamma}-rays has been investigated. Charge collection efficiencies of the detector for {alpha}-particles and {gamma}-rays detection were determined in both the normal state and the pumped state. The duration of the priming effect and its relationship with bias voltage were also studied. The results show that the priming effect may clearly improve charge collection efficiency, with an increase of 6% for {alpha}-particles and 13% for {gamma}-rays at 600 V saturation bias voltage. The priming effect can be completely retained for 40 min after irradiation, and it begins to gradually disappear within 12 h. In addition, the effect is more easily induced when bias voltage is applied than in the absence of any bias voltage. The experiments also demonstrated that irradiation incident on the growth surface may induce higher charge collection efficiency than irradiation incident on the substrate surface.

  7. Gamma-ray irradiation of a boreal forest ecosystem

    International Nuclear Information System (INIS)

    A long-term radiation ecology research project called Field Irradiator - Gamma (FIG) began at the Whiteshell Nuclear Research Establishment in 1968. The experimental area is in southeastern Manitoba and is located on the western edge of the Precambrian shield. The project studies the ecological effects continuous exposure to a gradient of gamma radiation has on a mixed boreal forest ecosystem. The gradient ranges from 1 to 460,000 times the natural background radiation level. This paper describes the forest, the gamma irradiator and its radiation field, and the research program

  8. Digested livestock wastewater treatment using gamma-ray irradiation and struvite crystallization

    International Nuclear Information System (INIS)

    Livestock wastewater generally contains high strength of organics (COD), ammonia nitrogen (NH4+ -N), phosphate phosphorus (PO43- -P) and suspended solids. It is very difficult to treat by conventional wastewater treatment techniques. In this study, struvite crystallization was carried out to treat the digested livestock wastewater. 1.0 :1.2 :1.2 was determined as an optimal NH4+ :Mg2+ : PO43- mol ratio of struvite crystallization. For the digested livestock wastewater, COD, NH4+ -N and PO43- -P removal efficiencies by struvite crystallization were 72.4%, 98.9%, and 74.8%, respectively. Gamma-ray irradiation was carried out prior to struvite crystallization of livestock wastewater. The enhancement of struvite crystallization efficiency could be obtained by the pretreatment of gamma-ray irradiation due to the decrease of COD, NH4+ -N and PO43- -P concentration

  9. Shoot regeneration of callus culture from irradiated sheed of piper nigrum L by gamma rays

    International Nuclear Information System (INIS)

    Shoot regeneration was obtained from callus that induced by irradiated seed with 25 and 50 Gy of gamma-rays and then on M.S. medium containing NAA 1 ppm and 2-ip 0.5 ppm. Irradiated seed with a dose of 25 Gy produced normal root and failed to produce shoot, but rice callus. Irradiated seed with a dose of 50 Gy pruduce callus only. Shoot differentiation occured after the callus were cultured on M.S., medium containing 2-ip 1 ppm and Kinetin 2.5 ppm. (authors). 9 refs, 3 figs

  10. Study of uptake and endocytosis of gamma rays-irradiated crotoxin by mice peritoneal macrophages

    International Nuclear Information System (INIS)

    The purpose was to investigate the uptake and endocytosis of 2000 Gy 60Co irradiated crotoxin through mouse peritoneal macrophages, correlating with native one and another non related protein, the ovalbumin. Native (CTXN) or 2000 Gy 60 Co ?-rays (dose rate 540 Gy/hour) irradiated crotoxin (CTXI) or ovalbumin processed of same manner (OVAN - OVAI) were offered to mouse peritoneal macrophages and their uptake was evaluated by immunohistochemistry and quantitative in situ ELISA. The involvement of scavenger receptors (ScvR) was evaluated by using blockers drugs (Probuco-PBC or Dextran Sulfate - SD) or with nonspecific blocking using fetal calf serum (FBS). The morphology and viability of macrophages were preserved during the experiments. CTXI showed irradiation-induced aggregates and formation of oxidative changing were observed on this protein after gamma rays treatment. By immunohistochemistry we could observe heavy stained phagocytic vacuole on macrophages incubated with CTXI, as compared with CTXN. Quantitatively by in situ ELISA, the sema pattern was observed, displaying a 2-fold CTXI incorporation. In presence of PBC or SD we could find a significant decrease of CTXI uptake but not of CTXN. However the CTXN uptake was depressed by FBS, not observed with CTXI. OVA, after gamma rays treatment, underwent a high degradation suffering a potent incorporation and metabolism by macrophages, with a major uptake of OVAI in longer incubation (120 minutes). Gamma rays (60 Co) produced oxidative changes on CTX molecule, leading to a uptake by ScvR-mice peritoneal macrophages, suggesting that the relation antigen-presenting cells and gamma rays-modified proteins are responsible for the better immune response presented by irradiated antigens. (author)

  11. Post irradiation changes of haematological parameters in mammals blood after high dose gamma rays

    International Nuclear Information System (INIS)

    In our experiment we monitored post irradiation changes of haematological parameters in rats after single total - body dose of gamma rays 15 Gy. Significant decrease was in the erythrocyte count at 6th day (P th day (P th day. In the white blood picture in all experimental groups was leukopenia (P < 0.001), which was characterized by neutrophilia (P < 0.001) and lymphopenia (P < 0.001). (authors)

  12. Characterization of hydrogel from polyvinyl alcohol solution under gamma rays irradiation

    International Nuclear Information System (INIS)

    Aqueous solution of polyvinyl alcohol at 2 percent concentration of mass was irradiated under gamma rays of 60Co. Hydrogel was synthesized without using any additives. It was found that the gel fraction of polyvinyl alcohol was described by the energy transfer model. Produced hydrogel swelled markedly by absorption when it is placed in the water and the swelling was also described by the energy transfer model. (author)

  13. Glasses, Coatings, Glues and Gamma-ray Irradiation

    International Nuclear Information System (INIS)

    Most of the alignment systems for LHC experiments use optomechanical elements confirming a network of points that are monitored by laser beams. LHC experiments, working at the expected nominal luminosity, will induce an extremely high irradiation. basic components such as glasses, coatings and glues may change and their performance may degrade significantly. We have tested various components and identified some of them that can stand 10 years of LHC operation. (Author) 11 refs

  14. Gamma-ray irradiation effects on some electronic devices used in control circuits

    International Nuclear Information System (INIS)

    The influence of gamma-ray irradiation on some electronic devices that are frequently used in most kinds of electronic circuits and apparatus was investigated. Before irradiation the I-V characteristic of the diodes and transistors and the time of the logical gates were measured. The devices were irradiated in 6 steps (1, 2, 2, 2, 3, 5 Mrads). the final total dose was 15 Mrads. The I-V characteristic and the delay time were measured after every irradiation step and compared with the measurements before irradiation. The above mentioned measurements were performed several times with different time distances after the final irradiation step in order to investigate the stability of the effects induced by irradiation. (author)

  15. Allogenic bone rods with freeze drying and gamma rays irradiation for treatment of fracture

    International Nuclear Information System (INIS)

    Opened reduction and internal fixation are the usual treatment of fracture, but both methods need a second operation for removal implants. The benefits of the bone rods are that they can avoid the removement of internal fixation and will be absorbed spontaneously. The bone rods are made of allogeneic compact bones with freeze-drying and gamma rays irradiation supplied by Shanxi Provincial Tissue Bank. The purpose of this study is to evaluate allograft reaction, the stability of the internal fixation, osteoinduction in the treatment of fracture using allogeneic bone rods with freeze drying and gamma rays irradiation. From May 1997 to May 1998, fourteen cases (male 12, female 2) of treatment were reviewed. The mean age was 37.3 (21-5 1). There were 3 medial malleolus fractures, 7 tibia and fibula fractures, 1 ulna and radius fracture, 1 lateral condyle of humerus fracture. The clinical results were satisfactory. Because the strength of the bone rods are weaker than that of screws, the bone rods are only indicated in the fixation of cancellous bones fracture and unloaded bone fracture. It can be used as a supplementary fixation of loaded bone. It is not indicated for fixation of comminuted fracture. More than two bone rods may be used in the fixation of fracture in order to get stability of the fracture and decrease stress between rods which will prevent the break of the bone rods. Allogeneic bone rods with freeze-drying and gamma rays irradiation can be used as implantsa rays irradiation can be used as implants of non-immunogenicity. There are no allograft reactions in all cases (including fever, leukocytosis, exudation or swelling in the wound). Although plenty of experimental studies have showed that freeze drying with gamma rays irradiation (below 50 KGy) would not destroy BMP of bone allograft, but there is no osteoinduction in our cases. The healing of a fracture and bridging external callus are similar as other operations. This new technique may have the following advantages compare with the screws: 1) there is no stress shielding, 2) no need for second operation for removing implants. Because there is no allograft reaction and lower price compared with other absorbable fixation material, we believe allogeneic bone rods with freeze drying and gamma rays irradiation are one of the excellent materials foic internal fixation

  16. Gamma-rays irradiation of greenwood cuttings cherry varieties

    International Nuclear Information System (INIS)

    Results are reported of irradiation of greenwood cuttings of the sweet cherry grafted varieties Napoleon, Drogans Gelbe and Ryzhdavishka Belvitsa, performed at 2500 R. The treated buds have been treated on rootstocks in a nursery and trees have been raised from the grafts in a planting. Different teratological alterations were observed in shoots of most trees developed from treated buds such as fasciations, bi-, tre-, and tetra-furcation as well as branchlets with a pseudodichotomical ramification. Several forms, having a very good fruit bearing and lower strength of growth than the initial varieties, were selected. A large number of slightly growing mutagenous forms were established of the Drogans Gelbe variety. Their fruits do not differ substantially from those of the initial varieties. (author)

  17. Irradiation effect of transistor by Co-60 gamma rays and electron beams

    International Nuclear Information System (INIS)

    In order to evaluate radiation resistance of semiconductor devices which are used in radiation environments of artificial satellites and nuclear power plants, effects of radiation on the DC gain, leak current and switching time of typical transistor devices were investigated. Tested devices are PNP bi-polar transistor (2SB603), NPN bi-polar transistor (2SC764) and power MOS transistor (2SK458). Irradiation were carried out by Cobalt-60 gamma rays and electron beams of 1 and 2 MeV at exposure rates ranging from 102 to 106 R/h, and at temperature ranging from -40degC to 100degC. The following results were obtained. (1) 2SB603: Changes of the DC gain and leak current are larger in low exposure rate irradiations, and large exposure rate dependency is observed. The DC gain change is based on mainly increase of the base current. The exposure rate dependency is observed in the reverse saturation current and voltage, but in the switching time. (2) 2SC764: The exposure rate and temperature dependencies on irradiation effect are not clear, and the radiation resistance is over two orders higher than 2SB603 in the various properties. (3) 2SK458: The exposure rate and temperature dependencies on irradiation effect are small. (4) Irradiation effect on 2SB603 by electron beams is smaller than that by gamma-rays, and the exposure rate effect is observed. No difference between electron beams and gamma rays is observed for 2SC764 and 2SK458. (author)

  18. Effect of gamma-ray irradiation on modeling equilibrium moisture content of wheat.

    Science.gov (United States)

    Yu, Y; Wang, J

    2007-10-01

    The experimental research found that gamma irradiation dose affected the equilibrium moisture content of wheat at the same relative humidity and temperature of ambient. Values of the equilibrium moisture content decreased with an increasing dose of gamma-ray irradiation during both adsorption and desorption. These were due to the changes of wheat starch granules and their water bound ability caused by different irradiation doses. Factor of irradiation dose was added in 3 widely used models for modeling the equilibrium moisture content of irradiated wheat, and the parameters in models were estimated based on the experimental data. Based on the study of correlation coefficient, mean relative error, and standard error the modified Chung-Pfost equation and the modified Henderson equation were found to fit the desorption and adsorption isotherms for wheat, respectively, in the range of experiment at conditions studied. PMID:17995598

  19. Effect of gamma-ray irradiation on the deoxygenation of salt-containing water using hydrazine

    International Nuclear Information System (INIS)

    In spent fuel pools at the Fukushima Daiichi nuclear power plant, hydrazine was added to salt-containing water in order to reduce dissolved oxygen. Hydrazine is known to reduce dissolved oxygen in high-temperature pure water, but its deoxygenation behavior in salt-containing water at ambient temperature in the presence of radiation is unknown. Deoxygenation using hydrazine in salt-containing water was thus investigated using a 60Co gamma-ray source and artificial seawater at room temperature. Water samples containing a small amount of hydrazine were irradiated at dose rates of 100 - 10,000 Gy/h. The concentration of dissolved oxygen in the water samples was measured before and after irradiation. Notably, a decrease in the dissolved oxygen was only observed after irradiation, and the dissolved oxygen concentration decreased with increasing dose rate and irradiation time. The rate of decrease in the amount of dissolved oxygen using hydrazine was slow in the presence of salts. Kinetic considerations suggested that the deoxygenation of the salt-containing water exposed to gamma-ray irradiation using hydrazine was suppressed by chloride ions. (author)

  20. Studies on the effect of gamma-rays irradiation on the virulence and immunogenicity of Eimeria tenella oocysts

    International Nuclear Information System (INIS)

    Complete attenuation of the infective oocysts of Eimeria tanella was obtained with a gamma ray dose of 15000r. Above this dose, pathogenicity and the sensitivity of the disease decreased. There was no difference in the level of immunity induced with irradiated and non-irradiated oocysts, but the mortality with the irradiated oocysts was much lower. (ARA)

  1. Fractionated Irradiation of Mice with Fission Neutrons and Co60 Gamma Rays

    International Nuclear Information System (INIS)

    This paper deals with the comparative effects of fission neutrons and Co60 gamma-rays, delivered at low dose rates over a 13-week period, on survival in CF No. 1 female mice. Animals were exposed in the gamma-neutron chamber at Argonne's CP-5 research reactor. The dose rate was approximately 0.75 rad/min for the neutrons and 0.25 rad/min for the gamma-rays. Fractionation of the weekly neutron dose into one, three, or six doses did not appear to have a significant effect on the mean survival times of the irradiated mice. Thymic tumours were observed in at least 90% of the mice that died following these fractionated exposures to either neutrons or gamma-rays. The RBE (n/?) for these 13-week exposures at low dose rates appears to resemble the acute RBE (2.8) rather than the higher value (5 to 15) reported when mice are exposed for the length of their lives to small daily doses. (author)

  2. Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

    International Nuclear Information System (INIS)

    The effects of neutrons and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 1013 n/cm 2 and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are given in this paper. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed

  3. Influence of gamma ray irradiation on the chemical components and cells of tea leaves

    International Nuclear Information System (INIS)

    Three-year-old Yabukita and Yamakai tea trees were irradiated with 60Co gamma ray of total dose of 2kr, 4kr and 6kr (0.8 kr/hr) on March 23, 1972. The new leaves of non-irradiated plants and those irradiated with 2kr were picked on April 26 and June 2, respectively. The trees irradiated with larger doses did not develop new leaves. Mature leaves were collected on June 16. The leaves, dried and powdered, were analyzed for their components. The irradiation increased the amino acids in the new leaves of both varieties to about twice as compared with that of the no-treatment control. In the mature leaves, the amino acid content was increased with the radiation dose up to 4 kr, but at 6 kr, it was decreased slightly. In both new and mature leaves, the gamma-ray radiation decreased the content of serine and glutamic acid. The content of theanine in the new leaves was increased by radiation, but that in the mature leaves tended to decrease both with the increase of the radiation dose. The new leaves of both varieties irradiated with 2 kr contained slightly more tannin than the controls. It was thought that the delay of picking in case of the irradiated trees caused the difference in the new leaves. In the mature leaves, the content of tannin tended to decrease with the increasing radiation dose. The content of chlorophyll a was lower in the new leaves of irradiated Yabukita, but the contents of chlorophylls a and b in the mature leaves and of chlorophyll b in the mature leaves and of chlorophyll b in the new leaves tended to be higher than those of the controls. The radiation increased the concentration of both chlorophylls a and b in the new and mature leaves of Yamakai. The leaves of both varieties after the irradiation showed smooth surfaces. (Kaihara, S.)

  4. Effect of gamma ray irradiation on deoxygenation by hydrazine in artificial seawater

    International Nuclear Information System (INIS)

    At the spent nuclear fuel pools in the Fukushima Daiichi Nuclear Power Plant, hydrazine has been added to reduce dissolved oxygen in the pool water containing salts. The reduction behavior of dissolved oxygen in seawater with hydrazine in the presence of radiation is unknown. The effect of gamma ray irradiation on deoxygenation by hydrazine in artificial seawater was investigated at room temperature. We placed the artificial seawater with a small amount of hydrazine under gamma ray irradiation at dose rates of 0.3-7.5 kGy/h. The concentration of dissolved oxygen in the solutions was measured before and after the irradiation. The concentration of dissolved oxygen hardly decreased in the absence of gamma radiation in a few hours, whereas it markedly decreased in the presence of gamma radiation. The concentration of dissolved oxygen decreased with irradiation time. At this moment, hydrazine concentration decreased more than twice the dissolved oxygen concentration. This shows that some gamma radiolysis products of hydrazine act as deoxidizers. The concentration of dissolved oxygen in artificial seawater could be decreased by the addition of a small amount of hydrazine in the presence of gamma radiation at room temperature. (author)

  5. Studies on the preparation and uses of Co-60 gamma-ray irradiated natural latex

    International Nuclear Information System (INIS)

    The properties are described of low-ammonia latex concentrates produced by gamma-ray irradiation (0.5 to 2.0 Mrad dose) in the presence of carbon tetrachloride or chloroform as sensitizer. Dipping trails with irradiated concentrates and irradiated field latex, for the preparation of condoms and medical gloves, gave products with high ultimate elongation, low modulus, and high permanent set. A change from straight dipping to coagulant dipping and a heat treatment after drying resulted in improved physical properties. A notable feature of products prepared from these materials is their purity, i.e., low content of rubber chemicals. An economic disadvantage, at the present time, is the high initial cost of the irradiation equipment

  6. Inhibitory mechanism of low-dose, whole-body irradiation with gamma-rays against tumor metastasis

    International Nuclear Information System (INIS)

    Complete text of publication follows. A lot of beneficial effects of low-dose irradiation are well known. Of them, an inhibitory effect of the radiation on lung metastasis is reported so far. It has been reported that low-dose whole-body irradiation with gamma rays enhanced cytotoxic immune response as one of the mechanisms. In our laboratory, it has been confirmed an enhancement of natural killer activity in mice irradiated with whole-body 0.5Gy gamma-rays. Metastasis is accomplished by multistep process, involving basement membrane destruction, local invasion, intravasation, survival in the bloodstream, extravasation into distant organs, and proliferation at the target site. Besides, a lot of growth factors and proteases are involved in these steps. As to mechanism of inhibition of tumor metastasis induced by low-dose whole-body irradiation, studies from the standpoint of tumor invasion have not been reported. Here, inhibitory effect of 0.5Gy whole-body gamma-ray irradiation on tumor metastasis and its mechanism were examined in pulmonary metastasis model mice injected with B16 melanoma cells. Consequently, 0.5Gy whole-body gamma ray irradiation significantly suppressed colony formation in the lungs. Expression of matrix metalloproteinase- 2 (MMP- 2), a proteinase related to metastasis, in lung tissues was suppressed by the radiation. Alteration of tissue inhibitor of matrix metalloproteinase (TIMP) after the gamma-ray irradiation was examined. Expression of TIMP-1 iation was examined. Expression of TIMP-1 and TIMP-2 mRNA in the lungs were significantly increased. In order to clarify the inhibitory effect obtained in the in vivo metastatic lung cancer model mice, we studied effects of gamma-rays on cell proliferation, alterations of mRNA and proteins related to tumor metastasis in cultured B16 melanoma cells. Proliferation of B16 melanoma cells was decreased in a dose-dependent manner. MMP-2 mRNA expression was not altered in any doses of gamma-rays. Thought expression of the protein was slightly decreased by 0.5Gy gamma-ray irradiation, there were no significant changes in the activity. Thus, it was concluded that 0.5Gy gamma irradiation had not any significant direct effects on cultured B16 cells. As a whole, it would be suggested that TIMPs were elevated in the in vivo metastatic model mice by low-dose gamma-ray irradiation, resulting in lowering MMP-2 by which tumor metastasis was inhibited.

  7. Radiation stability test of DEHPA and TBP extractants by irradiation with cobalt-60 gamma-rays

    International Nuclear Information System (INIS)

    This study was carried out to evaluate the radiation stability of di-(2-ethylhexyl) phosphoric acid (DEHPA) and tributyl phosphate (TBP) extractants by irradiation with Cobalt-60 gamma-rays. The degradation products were analysed with Gas Chromatography/Mass Spectrometer, NMR Spectrometer, Ion Chromatography and IR Spectrometer. It was found that the major radiolytic degradation products were mono-(2-ethylhexyl) phosphoric acid (MEHPA) and phosphoric acid (H3OP4) for DEHPA (DEHPA ? MEHPA ? H3PO4) and dibutyl phosphate (HDBP),monobutyl phosphate (H2MBP) and phosphoric acid for TBP (TBP ? HDBP ? H2MBP ? H3PO4), respectively

  8. Safeguards on the depleted uranium used in gamma ray irradiator as shield material

    International Nuclear Information System (INIS)

    Depleted uranium used in gamma ray irradiator as the shielding material was not completely investigated and properly reported by the Atomic Energy Act until now, The IAEA required to report the status of the companies using small amount of uranium and information for 42 NDT companies was declared in 1999. And IAEA inspector visited some company to confirm their declarations. The Additional protocol proposed as the strengthened safeguards system by the IAEA, which was ratified through the national assembly on February 9, 2004, and was entered into force on February 19, 2004. The government is investigating the amount, purpose and location of depleted uranium in the area of non-nuclear use.

  9. Life shortening, tumor induction, and tissue dose for fission-neutron and gamma-ray irradiations

    International Nuclear Information System (INIS)

    The primary focus of this program is to obtain information on the late effects of whole body exposure to low doses of a high linear-energy-transfer (LET) and a low-LET ionizing radiation in experimental animals to provide guidance for the prediction of radiation hazards to man. The information obtained takes the form of dose-response curves for life shortening and for the induction of numerous specific types of tumors. The animals are irradiated with fission neutrons from the Janus reactor and with 60Co gamma rays, delivered as single, weekly, or duration-of-life exposures covering the range of doses and dose rates. 6 refs

  10. Moessbauer studies of the gamma-ray-irradiation effects of 1,10-phenanthroline compounds

    International Nuclear Information System (INIS)

    Moessbauer and infrared spectroscopies have been applied to the study of the gamma-ray-irradiation effects on eleven iron 1,10-phenanthroline compounds: [Fe(phen)2X2] (X = Cl-, HCOO-, NCO-, 1/2Ox2-, 1/2Mal2-, CN-, and NO2-), [Fe(phen)3]X2.nH2O (X = Cl-, ClO4-, HCOO-, and NO2-), [Fe(phns)2] (ClO4)2.2H2O and [Fe(phnc)2](ClO4)2.H2O (phen = 1,10-phenanthroline, phns = 1,10-phenanthroline-2-carbothioamide, and phnc = 1,10-phenanthroline-2-carboxamide). For all the low-spin complexes except [Fe(phen)3] (HCOO)2.6H2O, no chemical changes were observed on the Moessbauer spectra after irradiation. All the iron(II) complexes in the high-spin state except [Fe(phen)2Cl2] and [Fe(phnc)2] (ClO4)2.H2O were, however, changed to iron(III) species under the influence of irradiation. Three iron(II) complexes in the intermediate-spin state were sensitive to gamma-rays. (author)

  11. Change of insulation resistance and mechanical properties of polyethylene irradiated with gamma ray in hot water

    International Nuclear Information System (INIS)

    The evaluation of the deterioration of the polymer insulation materials of cables for nuclear facilities in radiation environment is important for heightening the safety and reliability of reactor facilities. For upgrading LWRs and extending their life, it is necessary to carry out the more detailed evaluation of radiation resistance by simulating respective environment of use of the materials used. The behavior of deterioration of insulation materials when those are used for a long period in hot water while being exposed to radiation is an interesting problem in view of clarifying the deterioration mechanism in the compound effect of water, heat and oxygen. In this research, gamma ray irradiation was carried out in hot water to polyethylene having excellent electrical properties, and the change of chemical structure and the change of electrical and mechanical properties were measured from the gel proportion and swelling, thus the effects of water, heat and oxygen were examined, and the radiation resistance in compound environment was considered. In order to cause radiation oxidation deterioration in PE without lowering dose rate, irradiation was carried out by pressurizing oxygen. 1.0 mm and 0.5 mm thick low density polyethylene sheets were used, and Co-60 gamma ray was irradiated. Tensile test was carried out. In hot water, the mechanical properties remarkably lowered. (Kako, I.)

  12. Behavioral changes in rats prenatally irradiated with low dose of gamma-rays

    International Nuclear Information System (INIS)

    In this work, the effects of prenatal gamma-irradiation on behavior in adult Sprague-Dawley rats were studied. Four months old female rats were irradiated with a dose of 1 Gy of gamma-rays on day 15 of gestation. The offspring of irradiated mothers (n=26) and that of control, non-irradiated mothers (n=36) of both sexes at the age of 3 month were tested in Morris's water maze and in open field test. All experimental groups showed a tendency to shortening the time needed to reach the platform in each trial in Morris water maze. Statistically significant difference between irradiated and control rats was detected only in males on 3rd experimental day. The ability to remember the position of the platform was not altered in irradiated animals after a 4 day pause. In open field test, statistically significant differences in comparison with controls were detected in number of squares entered and in crossings of the central square (P ? 0.05) in males. These findings suggest, when comparing with results of other authors, that irradiation effects on postnatal behavior in rats are extremely dependent on the time point of irradiation and that a correlation exist between the developmental stage of the individual brain structures at time of irradiation and the late behavioral effects. (authors)

  13. Thermal, tensile and rheological properties of low density polyethylene (LDPE) processed irradiated by gamma-ray

    International Nuclear Information System (INIS)

    The aim of this paper is to investigate structural changes of low density polyethylene (LDPE) modified by ionizing radiation (gamma rays). The gamma radiation process for modification of commercial polymers is a widely applied technique to promote new physical-chemical and mechanical properties. Gamma irradiation originates free radicals which can induce chain scission or recombination, providing its annihilation, branching or crosslinking. The samples were prepare in hydraulic press in temperature 180 deg C after was irradiated with gamma source of 60Co at doses of 5, 10, 20, 50 or 100 kGy at a dose rate of 5 kGy/h in inert atmosphere. The changes in molecular structure of LDPE, after gamma irradiations were evaluated using thermogravimetric analysis (TGA) and tensile machine and oscillatory rheology. The results showed the variations of the properties depending on the dose at each atmosphere. (author)

  14. Radiation-induced degradation of cyclohexanebutyric acid in aqueous solutions by gamma ray irradiation

    Science.gov (United States)

    Jia, Wenbao; He, Yanquan; Ling, Yongsheng; Hei, Daqian; Shan, Qing; Zhang, Yan; Li, Jiatong

    2015-04-01

    The radiation-induced degradation of cyclohexanebutyric acid under gamma ray irradiation was investigated. Degradation experiments were performed with 100 mL sealed Pyrex glass vessels loaded with 80 mL of cyclohexanebutyric acid solutions at various initial concentrations of 10, 20, and 40 mg L-1. The absorbed doses were controlled at 0, 0.65, 1.95, 3.25, 6.5, 9.75, and 13 kGy. The results showed that gamma ray irradiation could effectively degrade cyclohexanebutyric acid in aqueous solutions. The removal rate of cyclohexanebutyric acid increased significantly with the increase of absorbed dose and the decrease of its initial concentration. At the same time, the removal of chemical oxygen demand (COD) was as effective as that of cyclohexanebutyric acid. The kinetic studies showed that the degradation of cyclohexanebutyric acid followed pseudo first-order reaction. Above all, the proposed mechanism obtained when NaNO2, NaNO3 and tert-butanol were added showed that the •OH radical played a major role in the gamma degradation process of cyclohexanebutyric acid, while •H and eaq- played a minor role in the gamma degradation process. The degradation products were identified by Fourier transform infrared spectroscopy (FTIR) and gas chromatography/mass spectrometry (GC/MS) during cyclohexanebutyric acid degradation.

  15. Molecular Alternations Induced in Human Cells Following the Irradiation with Low Doses of Gamma Rays

    International Nuclear Information System (INIS)

    Full text: We have shown previously, that human cervical carcinoma cells irradiated with low doses of gamma rays (HeLa1500) became resistant to several structurally and functionally unrelated drugs. The aim of the present study was to investigate the molecular mechanisms involved in this phenomenon. The interest was focused on the genes involved in the repair of DNA damage and apoptosis. The levels of corresponding proteins were determined by Western blot method. Our results show that the constitutive levels of the proteins involved in mismatch repair, as well as ERCC1 (which is important for excision repair), were not altered in HeLa1500 cells. The induction of apoptosis (following the treatment with cisplatin) was inhibited in HeLa1500 cells due to increased expression of BCL-2 and decreased expression of caspase 8. In conclusion, low doses of gamma rays may change the sensitivity of irradiated cells to the subsequent treatment with drugs due to the inhibition of apoptosis. (author)

  16. Effects of gamma ray irradiation on the struvite crystallization of livestock wastewater

    International Nuclear Information System (INIS)

    The struvite crystallization was applied to remove NH4+ in livestock wastewater. The ammonium ions can be very toxic to the aquatic creatures. In this experiments, the livestock wastewater from Gongju livestock wastewater treatment plant was used. The behaviors of various parameters such as pH, mole ratio of Mg2+ : NH4+: PO43- and reaction temperature for struvite crystallization of livestock wastewater and the effect of gamma ray irradiation were evaluated. As results, for the pH variation, the NH4+ removal efficiency showed the highest, 88%, at pH 9 ? 9.25. The removal efficiency of NH4+, Mg2+ and PO43- was showed highest when same molar ratio of Mg2+ and PO43- were applied. The NH4+ removal efficiency showed 82% at 7 .deg. C, and 90% at 30 .deg. C, with temperature. When the wastewater was irradiated with 20 kGy of gamma ray, NH4+ was removed as much as 83%

  17. Mutation induction in chrysanthemum through in vitro acute and chronic irradiations with gamma rays

    International Nuclear Information System (INIS)

    In Vitro culture of chrysanthemum variety 'Reagan Dark Splendid' was established using explants from axillary buds and ray florets. Shoots produced in vitro culture from axillary buds were irradiated with acute gamma rays of 30 Gy. While multiple shoots produced from in vitro culture of ray florets were irradiated with chronic gamma rays of 112 and 140 Gy. The irradiated shoots were then multiplied two times by single-node cuttings from M1V1 to M1V3. Controls and irradiated shoots were rooted, transferred to soil in the greenhouse, and finally transplanted in the field. Observation and measurement were made at flowering time for height, number of nodes per plant and flower colour mutation frequency. Flower colour mutation frequency among the irradiated plants with 30, 112 and 140 Gy was 8.2, 9.3 and 15.3% respectively. Eleven variants were selected among the M1V3 plants from 30 Gy dose treatment. Selected variants had flower colour varying from red, red-purple and yellow-orange. Nine variants were selected among the M1V3 plants from 112 Gy dose treatment. Selected variants had flower colour varying from red, red-purple, purple and yellow-orange. Sixteen variants were selected from 140 Gy dose treatment. They had flower colour varying from red-purple, purple, orange-red, yellow-orange and yellow. These variants were multiplied through in vitro culture as well as by conventional cuttro culture as well as by conventional cutting. They will be evaluated for their performance, stability and uniformity in the field, and for market value during the next planting season. (author)

  18. Effect of gamma rays on sex ratio, emergence and lifespan of cucurbits fruit fly dacus ciliatus (low) irradiated as pupae

    International Nuclear Information System (INIS)

    The result showed the pupae at the age 1 or 2 days old was very sensitive to all doses of gamma rays, the percentage of adults emerged was zero at the dose of 45 gray and highest and the gigh percentage of adults emergence was recorded when the pupae irradiated at five days ald and the mean percentage of emerged adults was approximated with that of the control group. This study also showed that there was an effect of gamma radiation on the average percentage of deformed at adult stage and it was about 1:1 (male: female). On the other hand, the mean lifespan of females and mice s adult were decreased as the dose of gamma rays increases and the pupae irradiated at youngest ages. The longest life span of females was recorded when the pipa irradiated at five days old with any of the gamma rays dose. (Author)

  19. The gamma-ray irradiation sensitivity and dosimetric information instability of RADFET dosimeter

    Directory of Open Access Journals (Sweden)

    Pejovi? Mili? M.

    2013-01-01

    Full Text Available The gamma-ray irradiation sensitivity to radiation dose range from 0.5 Gy to 5 Gy and post-irradiation annealing at room and elevated temperatures have been studied for p-channel metal-oxide-semiconductor field effect transistors (also known as radiation sensitive field effect transistors or pMOS dosimeters with gate oxide thicknesses of 400 nm and 1 mm. The gate biases during the irradiation were 0 and 5 V and 5 V during the annealing. The radiation and the post-irradiation sensitivity were followed by measuring the threshold voltage shift, which was determined by using transfer characteristics in saturation and reader circuit characteristics. The dependence of threshold voltage shift DVT on absorbed radiation dose D and annealing time was assessed. The results show that there is a linear dependence between DVT and D during irradiation, so that the sensitivity can be defined as DVT/D for the investigated dose interval. The annealing of irradiated metal-oxide-semiconductor field effect transistors at different temperatures ranging from room temperature up to 150°C was performed to monitor the dosimetric information loss. The results indicated that the dosimeters information is saved up to 600 hours at room temperature, whereas the annealing at 150°C leads to the complete loss of dosimetric information in the same period of time. The mechanisms responsible for the threshold voltage shift during the irradiation and the later annealing have been discussed also. [Projekat Ministarstva nauke Republike Srbije, br. 17007

  20. Detection of irradiated fresh fruits treated by e-beam or gamma rays

    International Nuclear Information System (INIS)

    Since about 1990, the amount of commercially irradiated food products available worldwide has increased. Commercial irradiation of foods has been allowed in Brazil since 1973 and now more than 20 different food products are approved. Among these products are a number of fresh fruits which may be irradiated for insect disinfestation, to delay ripening and to extend shelf-life. Today, there is a growing interest to apply radiation for the treatment of fruits instead of using fumigation or e.g. vapour-heat treatments, and an increased international trade in irradiated fruits is expected. To ensure free consumer choice, methods to identify irradiated foods are highly desirable. In this work, three detection methods for irradiated fruits have been employed: DNA Comet Assay, the half-embryo test and ESR. Both electron-beam (e-beam) and gamma rays were applied in order to compare the response with these two different kinds of radiation. Fresh fruits such as oranges, lemons, apples, watermelons and tomatoes were irradiated with doses in the range 0, 0.50, 0.75, 1.0, 2.0 and 4.0 kGy. For analysis, the seeds of the fruits were utilized. Both DNA Comet Assay and the half-embryo test enabled an easy identification of the radiation treatment. However, under our conditions, ESR measurements were not satisfactory

  1. Survival of embryo irradiated with gamma rays by embryo culture in Brassica pekinensis Rupr

    International Nuclear Information System (INIS)

    The effect of irradiation on the survival rates and embryonic development of Brassica pekinensis RUPR. (Varieties; Kashin, Kohai 65 nichi and kairyochitose) was investigated. The purpose of this study was to seek ways of increasing the survival rates of embryos such as B.oleracea obtained through embryo culture techniques after irradiation doses affecting seed fertility and germination, for the purpose of increasing mutation rates. Embryos at different developmental stages ranging from the globular to the early heart stages were irradiated with 20 KR of gamma rays at the daily rate 0L 20 KR or 10 KR (Fig.1 and Table 1). The embryos were excised from ovules 4 to 10 days after irradiation and cultured on White's medium. The shooting and rooting rates on the 34th day of culture were higher at the dose of 10 KR/day than 20 KR/day and were lower when the materials were irradiated at the young embryonic stage (Table 3). Varietal differences in the shooting and rooting rates were also observed. The irradiated embryos survived mainly in the state of callus. It was concluded that the embryo culture technique was successful when applied to irradiated embryos excised at the young embryonic stage and that the technique affected B.pekinensis less than B.oleracea

  2. Relationship between free volume and mechanical properties of polyurethane irradiated by gamma rays

    International Nuclear Information System (INIS)

    Polyurethane was irradiated at various gamma radiation doses up to 1,000 kGy at room temperature in nitrogen. Positron annihilation lifetime spectroscopy, tensile test and dynamic mechanical analysis were used to find the relationship between free volume and mechanical properties. An increase of the free volume fraction in soft segments (SS) and a decrease of the free volume fraction in hard segments (HS) during gamma radiation was observed and analyzed. The results showed that HS in polyurethane had the excellent resistance to gamma radiation, whereas SS had a tendency to degrade. The reason for the decrease of the strain at break and the ultimate tensile strength was analyzed, which showed the changes in the mechanical properties of polyurethane irradiated by gamma rays were mainly determined by the changes of free volume in SS. If the resistance properties of polyurethanes exposed to radiations need to be improved, SS should be paid more attention to. (author)

  3. Chemical and Biological Studies on Cumin Fruits Irradiated by GAMMA Rays for Conservation

    International Nuclear Information System (INIS)

    The aim of this study was to investigate the effect of different doses of gamma irradiation (0, 5, 10 and 15 KGy) and different storage periods (0, 3 and 6 months) in different package materials (cotton or polyethylene bags) on essential oil quality and chemical composition of cumin (Cuminum cyminum) fruits. On the other hand antimicrobial activity of treated cumin fruits essential oil and its extracts at 0, 5000, 10000, 20000 and 40000 ppm were investigated. Results showed that the highest essential oil % was obtained from fruits stored for 3 months in cotton bag without gamma irradiation. Concerning the effect of essential oil as antimicrobial agent, the highest antibacterial activity was obtained by essential oil isolated from irradiated polyethylene packed fruits at 5 KGy then stored for 3 months (Staphylococcus aureus) or irradiated polyethylene packed ones at 15 KGy without storage (Salmonella typhimurium). On the other hand, the highest antifungal activity against Aspergillus niger and Penicillium digitatum was obtained by essential oil isolated from unirradiated packed in polyethylene fruits then stored for 6 months. Non-stored packed in cotton bag fruits irradiated with gamma rays at 10 KGy produced essential oil with highest antiyeastal activity. Cumin fruits extract at 40000 ppm when combined with different treatments presented the highest antimicrobial activity (represents as inhibition zone) against all studied microbes except with P. digitatum. Cumin extract at 40000 ppm when extracted from irradiated packed fruits in polyethylene bags with gamma rays at 5 KGy without storage or with 6 months storage or irradiated at 15 KGy of packed fruits in cotton bag with storage for 3 months presented the highest significant inhibition zones against S. aureus. The same concentration of extracted cumin from uni radiated packed in cotton bag fruits and storage for 6 months presented the highest inhibition zone of S. typhimurium. Also, with the same concentration, extracted cumin from irradiated at 10 KGy of packed in cotton bag fruits without storage or in polyethylene and stored for 3 months presented the highest inhibition zones of A. niger. Cumin extract at 5000 ppm when extracted from irradiation at 10 KGy of packed in cotton bag fruits and stored for 3 months presented the highest values of P. digitatum. On the other hand, the superior concentration of cumin extract (40000 ppm) presented the highest antiyeastal effect when extracted from irradiated packed in polyethylene fruits at 10 KGy and stored for 6 months.

  4. EFFECT OF GAMMA RAY IRRADIATION ON INTERLAMINAR SHEAR STRENGTH OF GLASS FIBER REINFORCED PLASTICS AT 77 K

    International Nuclear Information System (INIS)

    It is known that an organic material is damaged by gamma ray irradiation, and the strength after irradiation has dependence on the gamma ray dose. These issues are important not only to make global understanding of electric insulating performance of glass fiber reinforced plastics (GFRP) under irradiation condition but also to develop new insulation materials. This paper presents the dependence of fracture mode and interlaminar shear strength (ILSS) on the material and the gamma ray irradiation effect on the fracture mode and the ILSS. 6 mm radius loading nose and supports were used to prompt ILS fracture for a short beam test. A 2.5 mm thick small specimen machined out of a 13 mm thick G-10CR GFRP plate (sliced specimen) showed lower ILSS and translaminar shear (TLS) fracture, although the same size specimen prepared from a 2.5 mm G-10CR GFRP plate (non-sliced specimen) showed ILS fracture and the higher ILSS. Both type of specimens showed the degradation of ILSS after gamma ray irradiation. The fracture mode of the non-sliced specimen changed from ILS to TLS fracture and no bending fracture was observed. The resistance to shear deformation of glass cloth/epoxy laminate structure would be damaged by the irradiation

  5. Effects of gamma Rays Irradiation on resistance of Pseudomonas aeruginosa in various condition

    International Nuclear Information System (INIS)

    The investigation of gamma tays 60Co irradiation effect on resistance of bacteri P.aeruginosa has been done.The objective of the research was to know the D10 value of bacteria P.aeruginosa. By using of distilled water,talc and peanut powder as carrier in dry,wet,O2 and N2 condition the bacteria of P.aeruginosa were irradiated on gamma rays of 60Co with dose of O to 2.5 kGy,and with dose rate of 5 and 10 kGy/h.After irradiation the bacteria of P. aeruginosa were cultured in media of the Tryptone Soya Agar and incubatedat temperature of 32±2oC for 3 days. The survival colonies were calculated,and the data were used to make the curve and to determine the D10 value. The results of the experiments showed that D10 value of irradiated bacteria of P.aeruginosain the disitilled water,talc and peanut powder as carrier were not high significant.Nevertheless the D10 value of the irradiated at dose rate 10kGy/h show more higher tendency than at dose rate 5kGy/h. The D10 value of irradiated bacteria in the N2 condition was higher,if compared with in the O2 condition

  6. Dependence of gamma-ray dose on annihilation processes of irradiation defects in Li2TiO3

    International Nuclear Information System (INIS)

    Dependence of gamma-ray dose on formation and annihilation behaviors of irradiation defects was studied by means of ESR. In the formation behavior of irradiation defects, the amount of irradiation defects and ratio of O2--center to O--center increased as the in gamma-ray dose increased. The annealing experiments showed that the amounts of E'-center and O-related defects which are the Frenkel pair decreased in the two temperature ranges of 300-400 and 550-650 K. The first and second stages were identified to reactions between E'-center and O--center and E'-center and O2--center, respectively. By comparing annihilation with formation behaviors of irradiation defects, it was revealed that the activation energy of annihilation for irradiation defects was influenced by the ratio of O2--center and O-related defects. Therefore, the annihilation process of irradiation defects was dominated by pyrolysis of O2--center.

  7. biotechnological studies on the irradiated potato (solanum tuberosum) with gamma rays

    International Nuclear Information System (INIS)

    Bacterial wilt or brown rot disease caused by Ralstonia solanacearum causes extensive annual losses of different crops especially potato crop. It is considered as one of the limiting factors for potato production and exportation in Egypt. Therefore, the main purposes of this study were to investigate the effect of gamma rays on two potato cultivars (Diamant and Spunta). And, to obtain new genotypes of potato resistant to bacterial wilt disease. This study was carried out in the field and Biotechnology laboratory of the Plant Res. Dept., Nuclear Res. Center, Inshas, Egypt and Genetics Dept., Faculty of Agricultural., Cairo Univ., during 2008-2011. In the field experiment, dry tubers of potato cultivars were irradiated by different doses of gamma rays (20, 30 and 40 Gy) to study the effect of gamma rays on the vegetative and yield traits. The results showed that there are no significant differences between cultivars for all studied traits except a number of tubers per plant trait. Also, there are only highly significant and significant differences between treatments for weight of tubers per plant and number of tubers per plant traits, respectively. However, there are only significant differences between the interactions of cultivars and treatments for plant height and weight of tubers per plant traits. Six genotypes were selected from M1V2 generation depending on high yield for RAPD analysis to determine their genetic variability from its parents at molecular level using 11 primers. The results of RAPD analysis showed that 11 primers generated 56 distinct bands of which 31 (55.4%) were considered as polymorphic. The similarity indices of six genotypes of potato and its parents ranged from 70 to 91%. The highest genetic similarity 91% was found between D20 genotype and its parent D0 (Diamant control). On the other hand, the lowest genetic similarity 70% was found between S30, S40 genotypes and its parent S0 (Spunta control). In the artificial infection experiment under in vitro condition, the irradiated and non-irradiated plantlets of potato were cultured on medium inoculated with local virulent isolate of R. solanacearum. The results showed that all in vitro plantlets of the treatments in Diamant and Spunta cultivars were susceptible except S20 treatment was resistant to the infection with R. solanacearum. Protein analysis showed that S20 genotype (resistant mutant) displayed 2 negative unique bands that may be responsible for resistance to R. solanacearum.

  8. Response of cancer stem-like cells and non-stem cancer cells to proton and {gamma}-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Fu Qibin; Quan Yi; Wang Weikang; Mei Tao; Wu Jingwen; Li Jia [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Yang Gen, E-mail: gen.yang@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Ren Xiaotang; Xue Jianming; Wang Yugang [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)

    2012-09-01

    Ionizing radiation is a widely used therapy for solid tumors. Compelling evidence indicates cancer stem-like cells (CSCs) exist in solid tumors, which is on the top of hierarchically organization and suggested to be involved in carcinogenesis, tumor invasion, recurrence and resistance to various forms of therapies. Understanding the response of CSCs to irradiation is of great importance to improve cancer curability. In present study, the response to proton and {gamma}-ray irradiation of these cells, including DNA damage and apoptosis were investigated experimentally. The results show that CSCs have higher resistance than non-stem cancer cells (NSCCs) to either proton or {gamma}-ray irradiation. In addition, compared with {gamma}-ray, proton irradiation is more efficient to kill CSCs at the same dose with lower survival as well as higher DNA damages. The results suggest that proton irradiation may have greater capability of eliminating CSCs for cancer radiotherapy than {gamma}-ray at the same dose, which in turn makes radiotherapy more efficient.

  9. The effect of red ginseng extract on superoxide dismutase activity in the kidney of gamma-ray irradiated mice

    International Nuclear Information System (INIS)

    This study was prepared to observe the change of enzyme activities in kidney treated with red ginseng extract in the gamma ray irradiated mice. Determine the activity of SOD, peroxidase, catalase in the kidney a period of 1 day, 2 day, 3 day, 4 day, 5 day after a saline injection or injection of red ginseng extract or gamma ray irradiated group into four classify. The activity SOD and catalase showed a tendency to increase and recovery at the early state but pay no regard. Where ase, the activity of peroxide restored and increased pay regard. A physiological saline injection group after gamma ray irradiation showed a tendency to diminish after remarkable increase of activity of SOD, peroxidase and catalase than control group. Injection group of red ginseng extract after gamma ray irradiation observed rapid recovery on activity of SOD, peroxidase, catalase than a saline injection group. Experimental result suggested that injection of red ginseng extract after irradiation have the recovery effect on the changed of activity of SOD, peroxidase and catalase against radiation injury

  10. Gamma rays irradiation process on a restored painting from the XVII century

    Energy Technology Data Exchange (ETDEWEB)

    Rizzo, Marcia M. [MRIZZO Laboratorio de Conservacao e Restauracao de Bens Culturais Ltda., Sao Paulo, SP (Brazil)], e-mail: mrizzo@mrizzo.com.br; Machado, Luci D.B.; Rela, Paulo R.; Kodama, Yasko [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)], e-mail: prela@ipen.br, e-mail: lmachado@ipen.br, e-mail: ykodama@ipen.br

    2009-07-01

    The aim of this work is to emphasize the importance of a previous study of the materials composition and behavior of any art work which will be treated by gamma radiation, as well as to use complementary procedures to prevent recontamination after the treatment, since this is a non residual method. As an example the object of study is a Peruvian painting from the 17th century, which has been restored, contaminated by mould, treated by gamma rays, put in a hermetic acrylic box and showed microorganisms growth after six years. A new treatment was performed using the same process and a complementary method using cloistering with anoxia atmosphere to prevent recontamination. Before the first irradiation the influence of irradiation process on the original painting and on the materials used in the restoration process were investigated. These data were extremely important in the decision of the use gamma irradiation again on the same art work. The results obtained allowed concluding that the irradiation with the recommended dose of 6.0 kGy (at the first time) was not sufficient to kill all the fungi specimens in the art work. On the other hand the irradiation with the dose of 6.0 kGy (at the first time) and 9.0 kGy (at the second time), according to the literature, would not damage the restored painting. (author)

  11. Gamma rays irradiation process on a restored painting from the XVII century

    International Nuclear Information System (INIS)

    The aim of this work is to emphasize the importance of a previous study of the materials composition and behavior of any art work which will be treated by gamma radiation, as well as to use complementary procedures to prevent recontamination after the treatment, since this is a non residual method. As an example the object of study is a Peruvian painting from the 17th century, which has been restored, contaminated by mould, treated by gamma rays, put in a hermetic acrylic box and showed microorganisms growth after six years. A new treatment was performed using the same process and a complementary method using cloistering with anoxia atmosphere to prevent recontamination. Before the first irradiation the influence of irradiation process on the original painting and on the materials used in the restoration process were investigated. These data were extremely important in the decision of the use gamma irradiation again on the same art work. The results obtained allowed concluding that the irradiation with the recommended dose of 6.0 kGy (at the first time) was not sufficient to kill all the fungi specimens in the art work. On the other hand the irradiation with the dose of 6.0 kGy (at the first time) and 9.0 kGy (at the second time), according to the literature, would not damage the restored painting. (author)

  12. A study on the irradiation effect of 60Co gamma ray on dental polymethylmethacrylate bonded parts

    International Nuclear Information System (INIS)

    In this paper we describe an experimental study on the irradiation effect of 60Co gamma ray on dental polymethylmethacrylate (P.M.M.A.) welding part, hot and cold polymerizing adhesion part. It was found that from the result of tension test, no remarkable change of mechanical property is found with any of the bonded parts by the irradiation dose up to 107 r., and no deterioration by irradiation is observed. And then, according to the results of bending test, it is found that, although the three different bonded parts have different features, the strength of the welded part and of the part adhered by hot polymerizing adhesive becomes lower by irradiation, and bending strength of the three parts converges on 6 kg/mm2 after irradiation within a range of 106 - 107 r.. Joint efficiency (= bonded part strength/base material strength) of 65 - 75% in tension and 50 - 62% in bending can be adopted. Fracture of the base material and of the Welded part are similar, and prove high bonding strength. (author)

  13. Immune response against bothropstoxin-I irradiated with 60Co gamma rays

    International Nuclear Information System (INIS)

    Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules. Very promising results were obtained when crude animal venoms, as well as isolated toxins, were treated with gamma rays, yielding toxoids with good immunogenicity. Ionizing radiation has proven to be a powerful tool to attenuate snake venoms toxicity without affecting and even increasing their immunogenic properties. However, little is known about the modifications that irradiated molecules undergo and even less about the immunological response that such antigens elicit. In the present work, we investigated the immunological behavior of bothropstoxin-I, a K49 phospholipase, before and after irradiation. Structural modifications of the toxin were investigated by SDS-PAGE and mass spectrometry. Aiming to compare the toxicity between native and irradiated forms of the toxin, an in vitro cytotoxicity assay, using CHO cells, was performed. Isogenic mice were immunized with either the native or the irradiated toxin. The circulating antibodies were isotyped and titrated by ELISA. According to our data, irradiation promoted structural modifications in the toxin, characterized by higher molecular weight forms of the protein (aggregates and oligomers). When analyzed by mass spectrometry, the irradiated bothropstoxin appeared in several oxidized forms. The cytotoxicity assay showed that the modified toxin was 5 folds less toxic than its native counterpart. Irradiated toxins its native counterpart. Irradiated toxins were immunogenic and the antibodies elicited by them were able to recognize the native toxin in ELISA. These results indicate that irradiation of toxic proteins can promote significant modifications in their structures, but still retain many of the original immunological properties. (author)

  14. Simulation technique on dose-rate distribution in a 60Co gamma-ray irradiation field

    International Nuclear Information System (INIS)

    Dose-rate distribution in irradiation field of 60Co gamma-ray was calculated using Monte Carlo photon transport code named as EGS4-SPG code. The dose rate values measured by the ionization chamber and the alanine dosimeter were compared with calculated ones for the evaluation of the validity of the calculation. As a result, the difference between measurements and the calculation value was within ± a few% except for a position very near the source for a wide board radiation source. The dose-rate distribution can be estimated using these numerical results at the beforehand planning of a board radiation source arrangement although dose-rate measurement should be done only for a position very near the radiation source, where calculated value disagreed. The dose rate distribution measurement after the radiation source arrangement enables us to save number of the dosimeter and measurement time. (author)

  15. Aqueous solution of iodide under gamma ray irradiation - fixation of iodide by adding soluble silver salt

    International Nuclear Information System (INIS)

    An experiment on the fixation of iodide by adding soluble silver salt in the aqueous solution under the gamma ray irradiation was performed to establish a method for confinement of methyl iodide formation during the severe accident of a LWR plant. The formation of methyl iodide in the water phase of sump tank in the reactor pressure vessel containment building was presumed in this study by the reason of being of much obscure parts on the formation mechanism and transfer behavior of the methyl iodide under the severe accident conditions. And the separate effects tests on the chemical behavior of silver iodide and methyl iodide were performed under the gamma ray irradiation. Though the high dependence on the accident events sequence or the plant construction for the formation and transfer behavior of the fission products iodine was inferred, it was shown from the experimental results as above that the method to confine the formation of the methyl iodide by adding the soluble silver salt into the sump tank water at the accident is desirable. In conclusion: The cobalt 60 gamma ray irradiation (1.3 x 106 R/h x 2.75 h) to the silver iodide just after the precipitation in the aqueous solution did not give the effect to the stability of the precipitate. The aqueous solutions shut up in the stainless steel bombs as below were irradiated by the gamma ray from the spent fuel assembly(6.6 or 6.9 x 105 R/h, 1 or 2 h), respectively; CsI (7.89 x 10-4 respectively; CsI (7.89 x 10-4 M), CsI (7.69) x 10-5?7.89 x 10-4 M) containing (COOH)2(5.56 x 10-5 M ?1.11 x 10-3 M), H3BO3(3.24 x 10-2 M) and CH3COOH (1.67 x 10-5 M?1.67 x 10-3 M), Fe3+ (1.79 x 10-3 M) and (COOH)2(2.2 x 10-4 M), or CsOH (3.2 x 10-6 M) and CH3COOH (1.67 x 10-5?1.67 x 10-3 M), respectively. The methyl iodide occurred in each bomb just, after the irradiation(max. 2.7 x 10-1 %), but the formation mechanism of methyl iodide in each solution above were not resolved. The methyl iodide dissolved in the aqueous solutions(6.44 x 10-2 M) were irradiated by the cobalt 60 gamma ray (1.4 x 106 R/h x 4 h), respectively. Thirty two % of the methyl iodide above(in average of 4 data) were decomposed to the iodine (I2) and the iodide (I-). The decomposition rate of methyl iodide dissolved in the aqueous solution was greater than that in the gaseous state, apparently. In the aqueous solution shut up in the glass container, the methyl iodide was formed from the reaction between the methyl radical donor(dimethyl sulfate, 1 x 10-3 M or 2 x 10-3 M) and the iodine-131 tracer(about 7 micro Ci) at the conversion rate of about 3.5 %. In the aqueous solution above, the formation of methyl iodide decreased distinctly by the cobalt 60 gamma ray irradiation (7 x 105 R/h x 1 h) or the addition of the silver nitrate (1 x 10-4 M). Under the severe accident conditions of LWR, when the main source of methyl iodide formation is due to the reaction between the methyl radical donor and the soluble fission products iodide(containing the iodine formed from the reaction between the oxidation products by water radiolysis and the iodide ion), the addition of adequate amounts of silver nitrate to the water phase just before the dissolution of soluble fission products iodine can decrease distinctly the formation rate of methyl iodide by producing the silver iodide precipitate. (author)

  16. Long-term effects in mice irradiated with low-dose gamma rays at juvenile period

    International Nuclear Information System (INIS)

    The present study was aimed to obtain dose-response relationships for the excess mortality from all causes and carcinogenesis after irradiation at juvenile period with gamma rays from 137Cs. B6C3F1 female mice were irradiated at 0 or 7 days of age with doses ranging from 0.19 to 5.7 Gy, and all the mice were allowed to live out their entire life span under a specific pathogenfree condition. The excess mortality in mice irradiated with 0.19 Gy at 0 day of age was estimated to be 8.8%. Mice of 7 days of age seemed to be more sensitive to induction of lethal diseases, as the excess mortality reached 22.3% after irradiation with 0.19 Gy. Dose-response relationship for the excess mortality was well described by an equation EM(D)=1- exp(-aD), where EM(D) represents excess mortality in a group irradiated with dose D. Incidences of liver tumors, pituitary tumors, ovarian tumors and lung tumors were significantly higher than control group in mice irradiated with doses lower than 1 Gy at 0 day of age. Shape of dose-response curves for these tumors was convex upward. Dose-response relationships were analyzed using a model which includes tumorigenic activity of radiation, sterilization of potentially tumorigenic cells and competing risks. Analysis of the experimental data showed that tumorigenic activity was proportional to dose for induction of these tumors. Relative risks at 1 Gy were estimated to be 2.52, 2.79, 16.5 and 3.17 for induction of liver tumors,.5 and 3.17 for induction of liver tumors, pituitary tumors, ovarian tumors and lung tumors, respectively. This result implies that mice of the neonatal period are highly susceptible to induction of these tumors. On the other hand, shape of dose-response curve for incidence of bone tumors was concave upward. Dose-response relationship for induction of bone tumors was fitted by a model that tumorigenic activity of gamma rays is proportional to square of dose. (author)

  17. Diversity analysis of mangosteen (Garcinia mangostana irradiated by gamma-ray based on morphological and anatomical characteristics

    Directory of Open Access Journals (Sweden)

    MUH RAHMAD SUHARTANTO

    2010-01-01

    Full Text Available Widiastuti A, Sobir, Suhartanto MR. 2010. Diversity analysis of mangosteen (Garcinia mangostana L. irradiated by gamma-ray based on morphological and anatomical characteristics. Nusantara Bioscience 2: 23-33. The aim of this research was to increase genetic variability of mangosteen (Garcinia mangostana L. irradiated by gamma rays dosage of 0 Gy, 20 Gy, 25 Gy, 30 Gy,35 Gy and 40 Gy. Plant materials used were seeds collected from Cegal Sub-village, Karacak Village, Leuwiliang Sub-district, Bogor District, West Java. Data was generated from morphological and anatomical characteristics. The result indicated that increasing of gamma ray dosage had inhibited ability of seed to growth, which needed longer time and decreased seed viability. Morphologically, it also decreased plant heigh, stem diameter, leaf seizure, and amount of leaf. Anatomically, stomatal density had positive correlation with plant height by correlation was 90% and 74%. Gamma rays irradiation successfully increase morphological variability until 30%. Seed creavage after irradiation increased variability and survival rate of mangosteen.

  18. Ageing evaluation of low voltage cables and insulators with gamma ray irradiation and thermal accelerated ageing tests

    International Nuclear Information System (INIS)

    To optimize lifetime prediction method of cables and to understand cable ageing mechanism, ageing evaluation of low voltage cables and insulators with gamma ray irradiation and thermal accelerated ageing tests were conducted. Insulators had no indication of the ageing after 1000 hours of the accelerated ageing tests. (author)

  19. DIVERSITY OF STRAIN EVALUATION THREE RICE (ORYZA SATIVA FENOTIPE GAMMA RAY IRRADIATED THE RESULTS OF GROWTH AND PRODUCTION

    Directory of Open Access Journals (Sweden)

    Sumarji

    2015-02-01

    Full Text Available Induction of mutations by gamma-ray irradiation is known as one of the techniques to develop new rice genotypes. The purpose of this study will provide a gamma ray irradiation on the growth and diversity of production lines AC6DH1-103, KA0048 and KA0052. The second objective is to obtain the optimum dose to increase growth and production lines AC6DH1-103, KA0048 and KA0052. The study of mutations induced by gamma-ray irradiation on the seeds, using completely randomized design with two factors, the first factor is genotype, namely: AC6 DH1 103, KA0048 and KA0052. The second factor is the dose of gamma-ray irradiation, namely: 0, 100, 150 and 200 Gy. Place rice improvement research through mutation induction performed at the Center for Application of Isotopes and Radiation Technology, National Nuclear Energy Agency (Batan, Jakarta Friday Market using Gamma Chamber-type 4000A and planting a seed irradiation and mutant screening conducted in the green house of the Faculty of Agriculture, Islamic University of Kadiri Kediri. Evaluation of agronomic characters of M0 generation potential mutants showed that the variation of the strain and the growing power of the radiation dose. Largest growing power of each strain ie, strain DH1 AC6 103 100% dose of 200 Gy, 84% KA0048 and KA0052 dose of 100 Gy 74% dose of 150 Gy. AC6 DH1 strain 103 (M0 is more responsive to gamma-ray irradiation proved significant interaction was found on the variable contains the number of seeds, number of seeds per hill and empty weight of 100 seeds compared to the control.

  20. Rhizobium sp. effects, irradiated with ultraviolet and gamma rays, on nodulation of P. vulgaris (L.) bean

    International Nuclear Information System (INIS)

    Indigenous isolates of Rhizobium sp. from the root nodules of bean were selected. There of these isolates and a R. leguminosarum biovar phaseoli (SEMIA 4064) strain, used as a reference, were irradiated with ultraviolet (UV) light and gamma-Rays (?-R). The relations between survival and fluence of UV, and survival and absorbed dose of ?-R were linear for the strain of reference. The D37 values, for this rhizobial strain were 43 j.m-2 for the UV-treatment, and 32 Gy for the ?-rays treatment. Through a greenhouse experiment the irradiated isolates were inoculated on bean seedlings (P. vulgaris L, Variety IPA-8), in an attempt to evaluate sensitivity of the host-plants and possible effects on their nodulation. Significant differences were observed only for root dry matter yield. For all the other evaluated parameters variance was of such magnitude that it was not possible to detect significance of the effects. The isolates tested showed difference in responses to nodulation, due to the effects of irradiations. The host plant (IPA-8) seemed to be sensitive to the possible modifications in the irradiated isolates. (author). 10 refs, 6 figs, 1 tab

  1. Prediction of crack propagation rate for stress corrosion cracking of stainless steel under gamma ray irradiation

    International Nuclear Information System (INIS)

    Under neutron and gamma-ray irradiation, radiolytic species are generated directly in the crack, which causes higher oxidant concentrations and then some exerts influence on crack propagation rate. A calculation model is proposed to predict water chemistry in the crack water under irradiation and then the crack propagation rate. The crack propagation model consists of the coupled processes of direct dissolution and oxide film generation/rupture at the crack tip. Calculation results confirmed that the concentrations of H2O2 were high enough to give higher local electrode potentials in both the bulk water and the crack tip water under irradiation (energy deposition rate: 0.1 W/cm3) under normal water chemistry (NWC), while the local electrode potential were still high in the bulk water but low in the crack tip water under hydrogen water chemistry (HWC). The proposed crack propagation model leads to the conclusion that HWC mitigates the crack propagation rate under irradiation, while the crack propagation model based on the local electrode potential difference between the bulk surface and the crack tip leads to the conclusion that HWC might enhance the crack propagation rate. (author)

  2. Study of irradiated bothropstoxin-1 with60Co gamma rays: immune system behavior

    Scientific Electronic Library Online (English)

    P, Caproni; JA, Baptista; TL de, Almeida; LAC, Passos; N, Nascimento.

    Full Text Available Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules. Very promising results were obtained when crude animal venoms, as well as isolated toxins, were treated with 60Co gamma rays, yielding toxoids with good immunogenicity. The achievement of modifi [...] ed antigens with lower toxicity and preserved or improved immunogenicity can be very useful. Ionizing radiation has already been proven to be a powerful tool to attenuate snake venom toxicity without affecting, and even increasing, their immunogenic properties. However, little is known about the modifications that irradiated molecules undergo and even less about the immunological response that such antigens elicit. In the present work, we investigated the immunological behavior of bothropstoxin-1, a K49 phospholipase, before and after irradiation. Structural modifications of the toxin were analyzed by SDS-PAGE. Isogenic mice were immunized with either the native or the irradiated toxin. The circulating antibodies were isotyped and titrated by ELISA. According to our data, irradiation promoted structural modifications in the toxin characterized by higher molecular weight forms of proteins (aggregates and oligomers). The results also indicated that irradiated toxins were immunogenic and antibodies elicited by them were able to recognize the native toxin in ELISA. These findings suggest that irradiation of toxic proteins can promote significant modifications in their structures; however they still retain many of the original antigenic and immunological properties of native proteins. Also, our data indicate that irradiated proteins induce higher titers of IgG2a and IgG2b, suggesting that Th1 cells are predominantly involved in the immune response.

  3. Study of irradiated bothropstoxin-1 with {sup 60}Co gamma rays: immune system behavior

    Energy Technology Data Exchange (ETDEWEB)

    Caproni, P.; Baptista, J.A.; Almeida, T.L. de; Nascimento, N. [Nuclear and Energy Research Institute (IPEN/CNEN-SP), SP (Brazil). Biotechnology Center; Passos, L.A.C. [State University of Campinas (UNICAMP), SP (Brazil). Lab. of Genetics and Embryo Cryopreservation

    2009-07-01

    Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules. Very promising results were obtained when crude animal venoms, as well as isolated toxins, were treated with 60Co gamma rays, yielding toxoids with good immunogenicity. The achievement of modified antigens with lower toxicity and preserved or improved immunogenicity can be very useful. Ionizing radiation has already been proven to be a powerful tool to attenuate snake venom toxicity without affecting, and even increasing, their immunogenic properties. However, little is known about the modifications that irradiated molecules undergo and even less about the immunological response that such antigens elicit. In the present work, we investigated the immunological behavior of bothropstoxin-1, a K49 phospholipase, before and after irradiation. Structural modifications of the toxin were analyzed by SDS-PAGE. Isogenic mice were immunized with either the native or the irradiated toxin. The circulating antibodies were isotyped and titrated by ELISA. According to our data, irradiation promoted structural modifications in the toxin characterized by higher molecular weight forms of proteins (aggregates and oligomers). The results also indicated that irradiated toxins were immunogenic and antibodies elicited by them were able to recognize the native toxin in ELISA. These findings suggest that irradiation of toxic proteins can promote significant modifications in their structures; however they still retain many of the original antigenic and immunological properties of native proteins. Also, our data indicate that irradiated proteins induce higher titers of IgG2a and IgG2b, suggesting that Th1 cells are predominantly involved in the immune response. (author)

  4. Study of irradiated toxins with 60Co gamma rays: immune system behavior

    International Nuclear Information System (INIS)

    Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules. Very promising results were obtained when crude animal venoms, as well as isolated toxins, were treated with 60Co gamma rays, yielding toxoids with good immunogenicity. The achievement of modified antigens with lower toxicity and preserved or improved immunogenicity can be useful. Ionizing radiation has been proven to be a powerful tool to attenuate snake venoms toxicity without affecting and even increasing their immunogenic properties. However, little is known about the modifications that irradiated molecules undergo and even less about the immunological response that such antigens elicit. In the present work, we have investigated the immunological behavior of bothropstoxin-I, a K49 phospholipase, before and after irradiation. Structural modifications of the toxin were investigated by SDS-PAGE. Isogenic mice were immunized with either the native or the irradiated toxin. The circulating antibodies were isotyped and titrated by ELISA. According to our data, irradiation promoted structural modifications in the toxin, characterized by higher molecular weight forms of the protein (aggregates and oligomers). Our data indicate that irradiated toxins were immunogenic and the antibodies elicited by them were able to recognize the native toxin in ELISA. These results indicate that irradiation of toxic proteins can promote significant modifications in their strute significant modifications in their structures, but still retain many of the original antigenic and immunological properties of native proteins. Also, our data indicate that the irradiated protein induced higher titers of IgG2a and IgG2b, suggesting that Th1 cells were predominantly involved in the immune response. (author)

  5. Study of irradiated bothropstoxin-1 with 60Co gamma rays: immune system behavior

    International Nuclear Information System (INIS)

    Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules. Very promising results were obtained when crude animal venoms, as well as isolated toxins, were treated with 60Co gamma rays, yielding toxoids with good immunogenicity. The achievement of modified antigens with lower toxicity and preserved or improved immunogenicity can be very useful. Ionizing radiation has already been proven to be a powerful tool to attenuate snake venom toxicity without affecting, and even increasing, their immunogenic properties. However, little is known about the modifications that irradiated molecules undergo and even less about the immunological response that such antigens elicit. In the present work, we investigated the immunological behavior of bothropstoxin-1, a K49 phospholipase, before and after irradiation. Structural modifications of the toxin were analyzed by SDS-PAGE. Isogenic mice were immunized with either the native or the irradiated toxin. The circulating antibodies were isotyped and titrated by ELISA. According to our data, irradiation promoted structural modifications in the toxin characterized by higher molecular weight forms of proteins (aggregates and oligomers). The results also indicated that irradiated toxins were immunogenic and antibodies elicited by them were able to recognize the native toxin in ELISA. These findings suggest that irradiation of toxic proteins can promote significant modifications in their structuregnificant modifications in their structures; however they still retain many of the original antigenic and immunological properties of native proteins. Also, our data indicate that irradiated proteins induce higher titers of IgG2a and IgG2b, suggesting that Th1 cells are predominantly involved in the immune response. (author)

  6. Levels of 2-dodecylcyclobutanone in ground beef patties irradiated by low-energy X-ray and gamma rays.

    Science.gov (United States)

    Hijaz, Faraj M; Smith, J Scott

    2010-01-01

    Food irradiation improves food safety and maintains food quality by controlling microorganisms and extending shelf life. However, acceptance and commercial adoption of food irradiation is still low. Consumer groups such as Public Citizen and the Food and Water Watch have opposed irradiation because of the formation of 2-alkylcyclobutanones (2-ACBs) in irradiated, lipid-containing foods. The objectives of this study were to measure and to compare the level of 2-dodecylcyclobutanone (2-DCB) in ground beef irradiated by low-energy X-rays and gamma rays. Beef patties were irradiated by low-energy X-rays and gamma rays (Cs-137) at 3 targeted absorbed doses of 1.5, 3.0, and 5.0 kGy. The samples were extracted with n-hexane using a Soxhlet apparatus, and the 2-DCB concentration was determined with gas chromatography-mass spectrometry. The 2-DCB concentration increased linearly (P patties. There was no significant difference in 2-DCB concentration between gamma-ray and low-energy X-ray irradiated patties (P > 0.05) at all targeted doses. PMID:21535632

  7. Corrosion of carbon steel and low-alloy steel in diluted seawater containing hydrazine under gamma-rays irradiation

    International Nuclear Information System (INIS)

    Seawater was injected into reactor cores of Units 1, 2, and 3 in the Fukushima Daiichi nuclear power station as an urgent coolant. It is considered that the injected seawater causes corrosion of steels of the reactor pressure vessel and primary containment vessel. To investigate the effects of gamma-rays irradiation on weight loss in carbon steel and low-alloy steel, corrosion tests were performed in diluted seawater at 50°C under gamma-rays irradiation. Specimens were irradiated with dose rates of 4.4 kGy/h and 0.2 kGy/h. To evaluate the effects of hydrazine (N2H4) on the reduction of oxygen and hydrogen peroxide, N2H4 was added to the diluted seawater. In the diluted seawater without N2H4, weight loss in the steels irradiated with 0.2 kGy/h was similar to that in the unirradiated steels, and weight loss in the steels irradiated with 4.4 kGy/h increased to approximate 1.7 times of those in the unirradiated steels. Weight loss in the steels irradiated in the diluted seawater containing N2H4 was similar to that in the diluted seawater without N2H4. When N2 was introduced into the gas phase in the flasks during gamma-rays irradiation, weight loss in the steels decreased. (author)

  8. Gamma Rays

    Science.gov (United States)

    ... Health Effects Ionizing & Non-Ionizing Radiation Understanding Radiation: Gamma Rays Ionizing & Non-Ionizing Radiation Main Page What ... family from gamma rays? The Basics Who discovered gamma radiation? Physicists credit French physicist Henri Becquerel with ...

  9. A high-capacity gamma-ray spectrometer facility in the NIST irradiation laboratory

    International Nuclear Information System (INIS)

    As the demand for greater throughput and shorter turnaround times for analytical work is increasing, instrumental neutron activation analysis (INAA) has come under pressure to substantially improve its performance in these areas. Of course, such improvements are expected without any loss of quality in other performance parameters, such as precision and accuracy. The National Institute of Standards and Technology (NIST) is responding to the aforementioned demands with increased utilization of short-lived ultrashort-lived nuclides and high-rate counting techniques in INAA. Part of this effort involves, in the course of the renovation of the NIST research reactor irradiation laboratories, the establishment of a newly designed gamma-ray spectrometry facility with three high-rate, high-resolution germanium detectors. The three detectors allow simultaneous counting of three samples and/or standards irradiated at the same time. The detector systems have been evaluated in a preliminary setup and are now being relocated in close proximity of the irradiation terminals to achieve short sample transfer times

  10. Meiotic chromosome behaviours in M1 generation of bread wheat irradiated by gamma-rays

    International Nuclear Information System (INIS)

    Growing plants of bread wheat (Triticum aestivum L. 2 n=6x=42, AABBDD) were subjected to acute or chronic irradiation by gamma-rays from 60Co and meiotic chromosome behaviours of PMCS in M1 generation were cytologically compared. Both acute and chronic irradiations produced different types of chromosomal aberrations at the meiotic stages. Among them, translocation type was the most frequent, followed by univalent type. A mixed type, i. e. translocation accompanying one or more univalents was often detected. Even normal type which lacked translocation and univalent included laggards and briclges without exception. Other meiotic abnormalities such as deletion, iso-chromosome and micronuclei were observed frequently in both treatments. Dose dependency of translocation frequency was not recognized in this experiment. In chronic irradiation, different chromosome numbers and meiotic behaviours were found not only among florets of a spike but also among anthers of a floret. A number of plants with aneuploid-like grass types occurred at a high frequency in M1, especially with low exposure

  11. Study of stability of humic acids from soil and peat irradiated by gamma rays

    International Nuclear Information System (INIS)

    Humic acids samples (one deriving from a sedimentary soil and other from a peat), in aqueous media, were irradiated with gamma rays, in doses of 10, 50 and 100 kGy, in order to understand their chemical behavior after the irradiation. The material, before and after irradiation, was analyzed by Elemental Analysis, Functional Groups (carboxylic acids and phenols), UV/Vis Spectroscopy (E4/E6 ratio), IR spectroscopy, CO2 content and Gel permeation Chromatography (GPC) ). The Elemental Analysis showed the humic acid derived from a peat had a most percentage quantity of Carbon and Hydrogen than the material from a sedimentary soil. From the UV/Vis Spectroscopy, it was observed a decrease of E4/E6 ratio with an increase of the applied dose. The data from GPC are in agreement with this. The results showed that the molecular weight of the material increased by exposing it to a larger radiolitical dose. The peat material was less affected by the gamma radiation than the soil material. The carboxylic groups were responsible by radiochemical behavior of the material. (author)

  12. Investigation of effects of gamma ray irradiation on pyrolysis properties of glove-box panel materials

    International Nuclear Information System (INIS)

    The glove box (GB) is a device with some plastic components and is used for the containment of radioactive materials. In a MOX fuel fabrication facility, MOX is also handled in the GB. Since the plastic panel, which has the largest area in the GB, is used over a long period, it is exposed to a high dose of MOX continuously. In this study, to confirm whether the containment capability of GB can be maintained even under external thermal stress, the effects of gamma ray irradiation with 60Co on the pyrolysis properties of the common panel materials were investigated by TG-DTA. As a result, polymethylmethacrylate showed a large peak of the mass loss rate at about 260 degrees under the nonirradiation and air condition, but it separated into lower and higher temperature sides above 25 kGy. This effect was not observed up to 10 kGy for polymethylmethacrylate and up to 880 kGy for polycarbonate. By comparison with the estimated total dose of the GB panel irradiated in the operation period, it was found that the irradiation from MOX does not significantly affect the pyrolysis properties of the GB panel in the actual facility. (author)

  13. X and gamma rays irradiation tests for evaluating performances of Italian dosimetry services

    International Nuclear Information System (INIS)

    The ENEA (Italian Agency for New Technologies, Energy and the Environment)-EDP Group (Personal Dosimetry Experts) has already evaluated the reliability of more than 50% of the 70 Italian personal dosimetry services, which agreed to test their dosimeters through X and gamma irradiation in air. Film,TL and both film and TL are used as detectors. The X and gamma rays energy ranges from 30 keV to 1.250 keV (beam defined by ISO 4037). Exposures range from 5.2 10-6 C/kg to 1.3 10-3 C/kg. Some dosimeters have been irradiated with a single energy level and others with two energy levels. For each one of the nearly 4.000 dosimeters already tested, the ratio R has been calculated: R = Xv/Xa where: Xv is the exposure evaluated by the service, Xa is the actual exposure. The R distributions have been analysed for the dosimeters using film or TL as detectors, as a function of irradiation energy and as a function of exposure values. The results obtained by all tested services are commented. Separate comments deal also with possible reasons of the failures to pass the tests

  14. Evaluation of myotoxic activity of Bothropstoxin-1 irradiated with 60Co gamma rays

    International Nuclear Information System (INIS)

    Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules and has been proven to be a powerful tool to attenuate snake venoms toxicity without affecting their immunogenic properties. Snake venoms and their isolated toxins showed structural modifications after gamma radiation process, in aqueous solution, mainly by water radiolysis sub products. Free radical scavengers, such as NaNO3 and t-butanol, present selective effects on specific radical from water radiolysis. The NaNO3 has affinity by aqueous electron, while the t-butanol has affinity by hydroxyl radical. At the present work, we have investigated the myotoxic activity of Bothropstoxin-1 (BTHX-1), a K49 phospholipase, present in Bothrops jararacussu crude venom, before and after irradiation process, with or without scavenger substances presence. BTHX-1 was irradiated with 2 kGy of 60Co gamma rays, in aqueous solution and in the presence of oxygen. BALB/c mice were inoculated with either native or irradiated toxin, with or without scavenger substances. After 3 hours, blood samples were collected and the myotoxic activity was evaluated by LDH (lactate dehydrogenase) release. The muscular tissue damage was directly related to the LDH amounts released. Irradiated Bothropstoxin-1, with or without NaNO3 substance, caused less damage than their native counterpart. But irradiated toxin, in the presence of t-butanol, was so myotoxic as the native BTHX-1. These results indicate that irradiation of toxic proteins can promote significant modifications on their structures, but still retaining many of the original biological properties of their native counterparts. Additionally, some scavengers substances can change these gamma radiation effects. (author)

  15. Continuous running test of radiation resistance motor driving equipment under high gamma ray irradiation

    International Nuclear Information System (INIS)

    The components in the vacuum vessel of ITER (International Thermonuclear Experimental Reactor), e.g. blanket and divertor, are replaced periodically using the dedicated remote handling systems. The environment conditions inside the vacuum vessel during the operation are temperature of 50degC, air or inert gas atmosphere at 1atm gamma ray radiation; therefore multiple factors shall be considered for establishment of durability of the remote handling systems. Concerning the dose rate of gamma ray under the anticipated operation of ITER, it was evaluated 10kG/h at the early stages of ITER EDA (Engineering Design Activity), but presently it decreases down to 0.5kGy/h after detailed design and evaluation have been done. However, a continual operation for one year at the longest is planned in the remote handling systems, therefore the systems it is desired to be able to operate longer than that. According to the requirements above, JAEA (Japan Atomic Energy Agency) advanced the development of radiation resistance components, major components of approximately 55 kinds which comprise the remote handling systems and that peripheral devices, since 1995 in ITER EDA. The dose rate and the target accumulation dose for the designated radiation resistance were set 10kGy/h and 10-100MGy, respectively. On the basis of the development results, the radiation resistance motor driving equipment, which comprised parts with different radiation resistance levels, was designed simulating mechanisms of ITER remote handling systems. The motor driving equipment, the servomotor turns the weight of 8kgf (dummy load) and controls, and continuous running test under high gamma ray irradiation was lasted approximately four years from March, 2000. Irradiation conditions on the test were; the dose rate of 3.6kGy/h, the accumulation dose of 30MGy at the minimum. The data were obtained, which are acquired motor electric current, temperatures and the breakdown event under the test conditions. In addition, appearance changes of every component and deice were observed. The irradiation test was performed in two stages, which was divided by a breakdown and successive overhaul of the equipment. The achieved accumulation dose and running time in those stages were approximately 47.6MGy/13,200hours and 23.9MGy/6,640hours, respectively. As a result, it has been confirmed that sufficient radiation resistance of the equipment, which is required against a dose rate of 0.5kGy/h at least, corresponding to the atmosphere inside the vacuum vessel, was achieved. Furthermore, the causes of breakdown at the 1st and the 2nd stages are hardening of the grease lubricant filled up in the reduction gear, and deterioration of electric insulation materials of power and signal lines, respectively. In this report, we describe design conditions and basic specifications of the radiation resistance motor driving equipment, the results of the 1st and the 2nd irradiation tests and the overhaul after the 1st stage irradiation test. (author)

  16. [The reduction of the dose to the lung in whole-body irradiation with cobalt-60 gamma rays (author's transl)].

    Science.gov (United States)

    Hochhäuser, E; Balk, O A

    1980-09-01

    In order to reduce the exposure of the lung and oesophagus during whole-body irradiation with cobalt-60 gamma rays the dose rate delivered to the lungs and the neck is diminished by means of a filter. Because of its special shape, sternum and columna vertebralis obtain the unreduced dose. The filter is constructed for irradiation in antero-posterior direction. A fixed position of the patient is not necessary. PMID:7434398

  17. Studying the Dosimetric Properties of GAMMA Rays Irradiated Chlorophyll Polyvinyl Alcohol

    International Nuclear Information System (INIS)

    Polyvinyl alcohol/chitosan/chlorophyll (PVA/Chit/Chl) films with about 2 mm thickness were prepared using gamma irradiation technique. The chlorophyll samples were extracted from fresh spinach leaves and PVA/Chit/Chl films were irradiated with gamma rays to study radiation-induced radicals as a dosimetric material using electron spin resonance (ESR), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). The ESR dose response and spectrophotometric analysis showed that chitosan decrease the response. The chlorophyll spectrum was characterized by dosimetric signal of spectroscopic splitting factor g = 2.0058. This signal is ascribed to the charge transfer complex of the molecular oxygen and the chlorophyll aggregate with strong pi-pi-interactions (aromatic interactions). The dose response was studied in the range from 1 to 500 kGy. Radical formation efficiency (G value) was obtained to be 0.15 ± 0.03. The dose conversion factors for chlorophyll in water and air were calculated to be 0.971 D water and 1.080 D air

  18. Manufacturing of a wood-plastic combination by irradiation of gamma-rays

    International Nuclear Information System (INIS)

    The studies on the wood-plastic combination (WPC) were carried out by gamma-ray irradiation. After impregnation of dry woods (Chamaecy Paris Obtusa ENDL., Cryptomeria japonica D.DON, Fagus renata BLUME., Acer mono MAXIM. and Shorea) with methyl methacrylate, emulsion of methyl methacrylate or unsaturated polyester (selfextinguishing type), the monomer in wood was polymerized by the irradiation. The percent of polymerization various monomers decreased remarkably in the presence of oxygen. WPC obtained were studied on the swelling, thermal and mechanical characteristics. The percent of welling in water of WPC impregnated with methyl methacrylate emulsion is less than that of WPC impregnated with methyl methacrylate (pure). WPC-polyester was shown to be non-inflammable. The pyrolysis gas of the WPC-methyl methcrylate and WPC-polyester is investigated, using a pyrolysis gas chromatography instrument. At the pyrolysis temperature of 3000C the decomposition gas prove to be mainly originated from the polymer in the WPC. The bending and compression strength of the WPC increased together with the weight of polymer in the wood. (auth.)

  19. Dose calculation method with 60-cobalt gamma rays in total body irradiation

    CERN Document Server

    Scaff, L A M

    2001-01-01

    Physical factors associated to total body irradiation using sup 6 sup 0 Co gamma rays beams, were studied in order to develop a calculation method of the dose distribution that could be reproduced in any radiotherapy center with good precision. The method is based on considering total body irradiation as a large and irregular field with heterogeneities. To calculate doses, or doses rates, of each area of interest (head, thorax, thigh, etc.), scattered radiation is determined. It was observed that if dismagnified fields were considered to calculate the scattered radiation, the resulting values could be applied on a projection to the real size to obtain the values for dose rate calculations. In a parallel work it was determined the variation of the dose rate in the air, for the distance of treatment, and for points out of the central axis. This confirm that the use of the inverse square law is not valid. An attenuation curve for a broad beam was also determined in order to allow the use of absorbers. In this wo...

  20. Perna perna (LINNAEUS, 1758) mussels irradiated by {sup 60}CO gamma rays cytotoxicity evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Martini, Gisela A.; Pusceddu, Fabio H.; Rogero, Sizue O.; Rogero, Jose Roberto, E-mail: gisela.martini@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The aim of the present work was the study of ionizing radiation effects on aquatic biota regarding the location of nuclear facilities nearby coastal areas assuming the risk of leaks and nuclear accidents. Bivalve mollusks have been widely used in the monitoring of aquatic environment studies mainly for their sessile habit and pollutants bioconcentration ability. So marine mussel Perna perna (Bivalvia: Mytilidae) was used as organism test in this study. The study of radioactive toxicity was performed by cytotoxicity test exposing the organisms to 11Gy gamma radiation dose. After radiation the neutral red retention assay evaluated the lysosomal membrane integrity in the mussel hemocytes. 50% lethal dose assay (LD50) of gamma radiation on Perna perna mussels was carried out by exposure the organisms to {sup 60}Co gamma rays at doses ranging from 0 to 3000 Gy. The result of gamma radiation LD50 for these mussels was 1068 Gy and the neutral red retention time of irradiated organisms was about 47% lower than the control, non irradiated organisms. With the obtained results is expected to contribute in the study to identify the range of ionizing radiation doses which can cause toxic effects in marine invertebrates. (author)

  1. Perna perna (LINNAEUS, 1758) mussels irradiated by 60CO gamma rays cytotoxicity evaluation

    International Nuclear Information System (INIS)

    The aim of the present work was the study of ionizing radiation effects on aquatic biota regarding the location of nuclear facilities nearby coastal areas assuming the risk of leaks and nuclear accidents. Bivalve mollusks have been widely used in the monitoring of aquatic environment studies mainly for their sessile habit and pollutants bioconcentration ability. So marine mussel Perna perna (Bivalvia: Mytilidae) was used as organism test in this study. The study of radioactive toxicity was performed by cytotoxicity test exposing the organisms to 11Gy gamma radiation dose. After radiation the neutral red retention assay evaluated the lysosomal membrane integrity in the mussel hemocytes. 50% lethal dose assay (LD50) of gamma radiation on Perna perna mussels was carried out by exposure the organisms to 60Co gamma rays at doses ranging from 0 to 3000 Gy. The result of gamma radiation LD50 for these mussels was 1068 Gy and the neutral red retention time of irradiated organisms was about 47% lower than the control, non irradiated organisms. With the obtained results is expected to contribute in the study to identify the range of ionizing radiation doses which can cause toxic effects in marine invertebrates. (author)

  2. Electrical insulating performances of SiC materials under gamma-ray irradiation

    International Nuclear Information System (INIS)

    For evaluation of electrical insulating performances of SiC materials in radiation and high temperature environments, electrical conductivities of single crystal and sintered SiC materials were measured under gamma-ray irradiations at temperatures of up to ?450degC. The radiation induced conductivities (RICs) evaluated for single crystal SiC plates were 2.8 x 10-8 – 1.3 x 10-7 S/m under the irradiations of 2.3 Gy/s at room temperature. The RICs in the sintered SiC plates were almost below measurable level due to their high inherent conductivities. The magnitudes of the RICs did not increase significantly with temperature. Extrapolation from the present data indicates that the maximum magnitude of RIC in SiC materials would be the order of 10-4 S/m for a dose rate of several kGy/s at a first wall of a fusion reactor. The magnitude is adequately lower than the allowable electrical conductivities in the SiC flow channel inserts (FCIs) for the dual-cooled lithium lead (DCLL) blanket design. (author)

  3. Mechanical Property Of Zeolite-PVA Composite Mixture Irradiated By Gamma Ray Of Co-60

    International Nuclear Information System (INIS)

    Experiment on preparation of zeolite-polyvinyl alcohol composite for absorbance materials have been done by curring using Gamma ?-ray of Co-60. Zeolite with the particles size of 60 mesh was mixed with polyvinyl alcohol (PVA) at the concentration of the mixture were 6,9, and 12% by weight, than they were poured into glass tube (length = 100 mm; diameter = 10 mm) and irradiated at the doses of 10, 20, 30 dan 40 kGy with the dose rate of 7,5 kGy/ hr. Parameters observed were density, compressive strength, and hardness. Experimental results showed that polyvinyl alcohol in the mixture was significant effect to density and compressive strength, where as the irradiation dose was highly significant effect to compressive strength. The effect interaction between dose and polyvinyl alcohol concentration factors had significant effect to density or compressive strength. Almost all samples have pencil hardness of 4 - 5 H, for composite containing 6 % PVA, has pencil hardness of 2 - 3 H

  4. Study on gamma-ray irradiation effects on corrosion resistance of canister material under the simulated disposal conditions

    International Nuclear Information System (INIS)

    The effects of gamma-ray irradiation on corrosion resistance have been studied about austenitic stainless steel as one of the candidate alloys for high-level radioactive waste canisters. The double U-bend specimens were used for the purpose of stress corrosion cracking (SCC) test on Type 304 ss and Type 309S ss. Sensitized Type 304 ss and Type 309S ss specimens were encapsuled respectively in capsules with a cubic granite and simulated groundwater. Test specimens were also encapsuled in a capsule with only humid bentonite in order to simulate the disposal environments. Capsules were irradiated with 137Cs source at WASTEF and with spent fuel in JMTR. The results showed that sensitized Type 304 ss have susceptibilities to SCC and sensitized 309S ss have not susceptibilities in the simulated disposal condition. On the other hand, no specimen was susceptible to SCC in deionized water even with gamma-ray irradiation. (author)

  5. Wavelet analysis of scintillation discharge current in DC tracking resistance of gamma-rays irradiated organic insulating materials

    International Nuclear Information System (INIS)

    The investigations on dc tracking resistance should be enhanced due to the increasing of organic insulating materials being used with dc power. This paper describes the influence of gamma-rays irradiation on dc tracking failure of organic insulating materials by use of the IEC Publ.112 method. Epoxy resin, polyethylene terephthalate and modified polycarbonate which were irradiated in air until 1x105 Gy and 1x106 Gy with dose rate of 104 Gy/h using a 60Co gamma-source have been used as the test samples. The total dose effects on the number of drops to tracking failure (or erosion depth), and scintillation discharge energy have been studied. The effects of gamma-rays irradiation on dc tracking failure are due to radiation-induced degradation or cross-linking of organic insulating materials. A wavelet analysis using gaussian wavelet is applied to show the scintillation discharge energy. (author)

  6. Effects of gamma ray and electron-beam irradiations on survival of anaerobic and facultatively anaerobic bacteria

    International Nuclear Information System (INIS)

    An extension of the approval for food irradiation is desired due to the increase in the incidence of food poisoning in the world. One anaerobic (Clostridium perfringens) and four facultatively anaerobic (Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Enteritidis) bacteria irradiated with gamma ray or electron beam (E-beam) were tested in terms of survival on agar under packaging atmosphere. Using pouch pack, effects of two irradiations on survival of anaerobic and facultatively anaerobic bacteria were evaluated comparatively. E-beam irradiation was more effective than gamma ray irradiation in decreasing the lethal dose 10% (D10) value of B. cereus at 4 deg C, slightly more effective in that of E. coli O157, and similarly effective in that of the other three bacteria at 4 deg C. The gamma irradiation of the bacteria without incubation at 4 deg C before irradiation was more effective than that of the bacteria with incubation overnight at 4 deg C before irradiation in decreasing the D10 values of these bacteria (B. cereus, E. coli O157, and L. monocytogenes). Furthermore, ground beef patties inoculated with bacteria were irradiated with 1 kGy by E-beam (5 MeV) at 4 deg C. The inoculated bacteria in the 1-9 mm beef patties were killed by 1 kGy E-beam irradiation and some bacteria in more than 9 mm beef patties were not killed by the irradiation. (author)

  7. Neutron and gamma ray irradiation effects on interlaminar shear strength of insulation materials with cyanate ester-epoxy blended resin

    International Nuclear Information System (INIS)

    A large scale fusion device like ITER requires high performance electric insulation materials against gamma ray and neutron irradiation, since fusion neutrons will reach superconducting magnets and activate them. Cyanate ester resin has been studied as a strong candidate for a new insulation material for fusion devices, and it has been clarified that the blended resin with epoxy has a potential to survive a design period in the radiation environment. This paper describes the results of molecular structure analysis of the blended resin, heat flux measurements by differential scanning calorimetry and the gamma ray and the fission neutron irradiation effects on interlaminar shear strength (ILSS) at 77 K. The gamma ray irradiation of 10 MGy did not change the ILSS significantly, but the neutron fluence of 1.0 x 1022 n/m2 (>0.1 MeV) with over 400 MGy degraded the ILSS. It suggests that cyanurate (triagine ring) will have a resistance against irradiation but oxazolidinon will lose the resistance after heavy irradiation.

  8. Obtainment of a drug delivery system from PVAL irradiated by gamma rays

    International Nuclear Information System (INIS)

    The poly(vinyl alcohol) (PVAL) is a polymer used as biomaterial. In this work the PVAL was irradiated by gamma rays from 60Co source with doses up to 200 kGy. The PVAL was used to prepare hydrogels that may be used as a drug delivery system in ocular implant, for pair PVAL/dihidroxypropoximethyl guanine, where the last one is used for treatment of people with retinite caused by cytomegalovirus. The dose effect was studied on various properties of PVAL: the molecular weight by viscosity, the crosslink degree (Gcross-link= 8,5) calculated from gel dose (Dg = 7,8 kGy), the average molecular weight between crosslinks, crosslinking density, tensile strength at break and the degree of crystallinity by differential scanning calorimetry. Formation and thermal decay radical were studied by electronic paramagnetic resonance. It was used the technique of superposition and subtraction of spectra obtained at various temperatures (77 K, 125 K, 170 K, 230 K and 280 K). The radicals formed were identified on irradiated PVAL on vacuum and air at 77K with 20 kGy. The thermal decay showed that air caused polymer oxidation, even after end the irradiation, because the ·OH, RO· and ROO · radicals were formed. The dose effect on molecular structure of PVAL was studied by transmission spectroscopy on infrared region and nuclear magnetic resonance of proton. The PVAL structural alteration was not observed up to 200kGy, although crosslink occurred on PVAL. The PVAL hydrogel formation occurred at doses upper 70 kGy and drug controlled released occurred with zero order kinetic on PVAL hydrogel irradiated with 80 kGy. (author)

  9. Teratogenic effects of 60Co gamma rays irradiation on rat embryos

    International Nuclear Information System (INIS)

    The teratogenicity of 60Co gamma rays was evaluated in Donryu rats. The results were compared with those of triterated water (HTO) for determining relative biological effectiveness (RBE) for incidence of malformations and LD50 in rats. Pregnant rats were irradiated with a 60Co source at a dose-rate of 0.5 Gy/min or 0.01 Gy/min on day 7, 8, 9, 10 or 11 of gestation with 0.8, 1.0, 1.2, 1.5, 2.0, 2.3, 2.5, 2.8 or 3.0 Gy. HTO was administered intraperitoneal injection to pregnant rats at various doses on day 7, 8, 9, 10 and 11 of gestation. The rats were sacrificed on day 18 and the offspring were examined for external and visceral malformations. Mortality, teratogenicity and effects on fetal growth were day-and dosage-dependent in both radiation groups. Congenital malformations were found most frequently in the 9-day irradiated group and followed by the 8, 11, 10 and 7-day irradiated groups. The incidence of cardiovascular anomalies was highest, especially in the day 9 of gestation group, followed by malformations in the central nervous system, craniofacial system, respiratory system, hind limbs and tail. Beta rays from HTO were found to be more effective than ? rays in inducing congenital malformations. The RBE for incidence of malformations and LD50 was between 1.3 and 1.5. These studies suggest that simulator of tritium irradiation is urgently needed to investigate the biological effects on rats to estimate the human risks,ects on rats to estimate the human risks, with respect to RBE of tritium beta rays. (author)

  10. Effects of 2. 0 Gy of /sup 60/Co gamma rays irradiation on rat embryos

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Juing-Yi; Satow, Yukio

    1987-01-01

    Pregnant rats of Donryu strain were exposed to a whole-body /sup 60/Co ..gamma.. ray irradiation of a single dose of 2.0 Gy (Dose rate: 0.5 Gy/min) on day 7, 8, 9, 10 or 11 of gestation (sperm day = day 0). The rats were sacrificed on day 18 and the offspring were examined for external and visceral malformations. Malformed embryos occurred between days 7 and 11 with the highest incidence occurring on day 9. Dose with 2.0 Gy increased the rate of resorption or death (52.1 %), in the survivors, caused congenital malformation in a majority of embryos (86.5 %) on day 8 of gestation. There is an increase in malformation (93.3 %) and growth retardation, but no increase in mortality (42.9 %) on day 9 of gestation. Relatively few anomalies resulted from irradiation on day 7 of gestation. The peak day for cardiovascular anomalies occurred on day 9 (88.3 % of all survival embryos) with high levels also occurring on day 8 (86.5 %). Cardiovascular anomalies consisted of VSD, hypoplasia of the pulmonary trunk, coarctation of the aorta, double aortic arch, right aortic arch, riding aorta, complete transposition of the aorta, persistent atrioventricular canal, vascular ring, aberrant right subclavian artery and others. Similar anomalies, but at a lower incidence, were produced by /sup 60/Co ..gamma.. ray at dose levels of 2.0 Gy on day 10 or 11 of gestation. Cases of cleft lip and cleft palate or facial cleft were observed seventeen fetuses on day 9 of gestation (31 %). Exencephaly occurred in nine embryos treated on day 9 (16.1 %) and in one embryos treated on day 10. Tail defects appeared with treatment on day 9 with the latter predominating on day 11. The present study show that maximum resorption (52.1 %) was seen with treatment on day 8 whereas the highest rate of malformation (93.3 %) was observed with treatment on day 9. (J.P.N.).

  11. A study on the effect of 60Co gamma ray irradiation on the abrasion of dental polymethylmethacrylate, (3)

    International Nuclear Information System (INIS)

    This report intends to clarify the relationship between the total exposure dose and scratch resistance to the specimens SF, SH, MF and MH, giving coating treatments to P.M.M.A. (dental polymethylmethacrylate) and exposing to the irradiation of 60Co gamma ray at each dose rate. And based on the results, it is intended to develop coated P.M.M.A. with excellent scratch resistance give by irradiation of radioactive ray. From this study, the following results have been obtained. Irradiation of 60Co gamma ray would give the best results at the exposure at 1 x 106 R. The SF and SH specimens in wet condition exposed to 60Co gamma ray irradiation at 1 x 106 R showed a quantity of abrasion of only 17% that of untreated P.M.M.A. and the barrel test revealed outstanding abrasion and scratch resistance. Abrasion and scratch resistance of coated specimens are better utilized in wet conditions performing three times better than those in dry conditions. (author)

  12. Repair rates of DNA double-strand breaks under different doses of proton and {gamma}-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jingwen; Fu Qibin; Quan Yi; Wang Weikang; Mei Tao; Li Jia [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Yang Gen, E-mail: gen.yang@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Ren Xiaotang; Xue Jianming; Wang Yugang [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)

    2012-04-01

    It is known that DNA double-strand breaks (DSBs), which can be induced by a variety of treatments including ionizing radiation (IR), can cause most deleterious consequences among all kinds of DNA lesions. However, it is still under debate about whether DSBs repair is equally efficient after low and high-LET radiation, especially the basic biological responses after exposure to high-LET particles. In present study, synchronous fibroblast normal Human lung fibroblast (NHLF) cells were irradiated with graded doses of proton and {gamma}-ray. Then {gamma}-H2AX foci assay was used to monitor DSBs induction and repair at 0.5, 1, 2, 4, and 18 h post irradiation. The results showed that the {gamma}-ray irradiation could produce more {gamma}-H2AX foci than proton irradiation at the same dose. However, compared to low LET radiation with {gamma}-ray, the results also showed a much slower DSBs repair rate after high LET radiation with protons, suggesting that the cellular ability to eliminate DSBs after low and high-LET ionizing radiation is quite different.

  13. Effect of gamma-ray irradiation in vitro on the inhibition activity of hen's egg white ovomucoid

    International Nuclear Information System (INIS)

    The ovomucoid radiosensitivity is investigated under certain condition (irradiation dose, protein concentration, storage time after irradiation) and it is compared with that of ovomucoid substrate - trypsine. A chromatographically homogeneous ovomucoid preparation was used. The protein concentration of the solutions was determined on a UV-spectrophotometer UNICAM SP 180. The irradiation was performed with a 60Co-gamma-ray source at a dose rate, amounting to 6,6 and 225,2 rads per second, the temperature of the solutions before and during the irradiation and up to the post-irradiation assays were controlled at 00 C. Conclusion has been drawn out that just as other proteins, even though more slightly, the ovomucoid is sensitive to the indirect action of the ionizing, and to high gamma-ray doses in particular. The effect of irradiation depends on the protein concentration in the solution and on the post-irradiation storage time. In addition to the other reasons, such as an increase in the permeability of the cellular membrane and possibly the biosynthesis of the peptidehydrolases in the cell, adaptively intensified, the radioactivity of the natural proteinase inhibitors is the cause for the manifestation of the ''stimulating'' effect of the radioactive irradiation on the activity of proteases when irradiated in vivo. (K.M.)

  14. A study on the effect of 60Co gamma ray irradiation on the abrasion of dental polymethylmethacrylate, (1)

    International Nuclear Information System (INIS)

    In this study we investigated about improvement of abrasion resistance on the dental polymethylmethacrylate. That is to say, di- and tri-methacrylic acid esters and di- and tri-allyl compounds are used as cross linking monomer to coat polymethylmethacrylate, irradiated with 60Co gamma ray to bring about linking reaction and improvement in linking density, so that the abrasion resistance of the dental polymethylmethacrylate can be improved. It was found that to add di-allyl compound to unsaturated polyester, to coat the with curing catalyzer add with methylethylketoneperoxide and naphthenic acid cobalt, and to irradiate with 60Co gamma ray to enrich cross linking density after hot press processing were very effective as a treatment to improve abrasion resistance of dental polymethylmethacrylate. (author)

  15. A {gamma}-ray irradiation route to fabricate monodisperse zinc sulfide hollow spheres using silica as templates

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Yongbin [State Key Laboratory of Fire Science and Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Shi Wenfang [State Key Laboratory of Fire Science and Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China)]. E-mail: wfshi@ustc.edu.cn; Gong Ming [Lab of Mechanical and Material Science, University of Science and Technology of China, Hefei, Anhui 230026 (China); Yu Fei [Lab of Mechanical and Material Science, University of Science and Technology of China, Hefei, Anhui 230026 (China); Chen Tiantian [State Key Laboratory of Fire Science and Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2005-12-15

    The monodisperse submicrometer zinc sulfide (ZnS) hollow spheres were synthesized by {gamma}-ray irradiation at room temperature, using monodisperse silica spheres as the templates. In order to obtain ZnS hollow spheres, the ZnS-coated SiO{sub 2} core-shell particles were prepared through {gamma}-ray irradiation deposition in an aqueous containing zinc acetate and sulfide, released through the hydrolysis of thioacetamide, followed by dissolving the SiO{sub 2} cores using hydrofluoric acid. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV-vis spectroscopy were used to characterize these nanoparticles, indicating the formation of core-shell colloidal spheres, as well as hollow spheres.

  16. Radiolytic degradation of hexabromocyclododecane in waste water from thermal insulation-treatment factory with gamma ray irradiation

    International Nuclear Information System (INIS)

    Radiolytic, and radiolytic/biological decompositions of hexabromocyclododecane (HBCD) in primary and ultimate waste waters from a thermal insulation-treatment process and a factory of polyester process are studied with gamma ray irradiation. Concentrations and degradation ratios of HBCD, and Br- concentrations are determined before and after gamma ray irradiation. Also, total organic carbon (TOC), chemical oxygen demand (COD), and biochemical oxygen demand (BOD) are determined to evaluate the decomposition of total organic compounds. As a result, about 72.5% of HBCD in ultimate waste water were decomposed with dose of 100 kGy. Furthermore, about 98% of HBCD, nearly all organic compounds were removed after the combination of radiolytic/biological treatments. (author)

  17. Induction of drought tolerance in tomato using 60Co gamma ray irradiation

    International Nuclear Information System (INIS)

    Drought is one of the environmental limitations that affects, on a higher degree, the production of different crops including tomato. A tomato breeding program was started to develop varieties suitable for growing under low water input conditions, which is not only important for saving this valuable liquid but also for diversifying food production in drought-affected areas. Two Cuban tomato varieties (INCA 9-1 and Amalia) were irradiated by 60Co gamma rays at doses of 300 and 500 Gy. In M2 generation, plants were cultivated in two zones of the country (Holguin and Havana province) in the months of lower precipitation (December-March). Irrigation was made three times at transplanting stage. Plants were grown in the short rainy season to keep suitable conditions for a promising genotype selection. During the following six generations selection was made for genotypes of high-yield, large fruit, high yield, disease resistance and fruit quality. In M6 generation, evaluation was conducted under water stress conditions for 60 plants of each of the best mutant lines, four of them from INCA 9-1 variety and three from Amalia variety.The mutant lines M15, M17 and M19 have been further evaluated in different areas of the country and they have shown very good behavior

  18. Fillers for gamma ray-irradiated EPR and ultralow frequency dielectric characteristics

    International Nuclear Information System (INIS)

    Aiming at the diagnosis of the radiation deterioration of electric power cables and wires by utilizing residual voltage, the relation of the amount of gamma ray irradiation with residual voltage has been examined for the EPR of practical mixing proportion by the authors. Moreover, as the characteristics or physical quantities used for judging the deterioration, the dielectric characteristics in ultralow frequency region and insulation resistance were taken up, and the method of analytically determine them from the results of measuring residual voltage was proposed. When the results obtained by this analytical method were compared with the results of leak current and discharge current, good agreement was obtained. However, since many kinds of fillers are added to these samples with practical mixing proportion in large quantities, it was unable to examine in detail the physical mechanism of depolarization which becomes the cause of generating residual voltage. This time, the discharge current was measured for the samples of EPR filled with only one kind of filler, hard clay, and the modeling of depolarization mecanism was attempted. The results are reported. (K.I.)

  19. Stability Test For Sorghum Mutant Lines Derived From Induced Mutations with Gamma-Ray Irradiation

    Directory of Open Access Journals (Sweden)

    S. Human

    2011-12-01

    Full Text Available Sorghum breeding program had been conducted at the Center for the Application of Isotopes and Radiation Technology, BATAN. Plant genetic variability was increased through induced mutations using gamma-ray irradiation. Through selection process in successive generations, some promising mutant lines had been identified to have good agronomic characteristics with high grain yield. These breeding lines were tested in multi location trials and information of the genotypic stability was obtained to meet the requirements for officially varietal release by the Ministry of Agriculture. A total of 11 sorghum lines and varieties consisting of 8 mutant lines derived from induced mutations (B-100, B-95, B-92, B-83, B-76, B-75, B-69 and Zh-30 and 3 control varieties (Durra, UPCA-S1 and Mandau were included in the experiment. All materials were grown in 10 agro-ecologically different locations namely Gunungkidul, Bantul, Citayam, Garut, Lampung, Bogor, Anyer, Karawaci, Cianjur and Subang. In each location, the local adaptability test was conducted by randomized block design with 3 replications. Data of grain yield was used for evaluating genotypic stability using AMMI approach. Results revealed that sorghum mutation breeding had generated 3 mutant lines (B-100, B-76 and Zh-30 exhibiting grain yield significantly higher than the control varieties. These mutant lines were genetically stable in all locations so that they would be recommended for official release as new sorghum varieties to the Ministry of Agriculture

  20. Reaction of nuclear graphites with water vapor in helium under gamma ray irradiation

    International Nuclear Information System (INIS)

    The reaction of four kinds of nuclear graphites with water vapor in helium were carried out under Co-60 gamma ray irradiation of 1.25 x 106 R/hr, at temperatures 30 - 2430C and at concentrations 0.6 - 2.3 volume percent. Radiation induced reaction rate of the graphites were found to be in the order of 10-9 g/g.hr at the concentration 1.2 volume percent, showing some differences between the graphites. There was no closed relation between the reaction rate of the graphites and their specific surface area, as well as their prosity. Impurity contained in the graphite gave little effect on the radiation induced reaction rate, although the impurity accelerated the thermal reaction rate. 7477 and 7477PT graphites, which have a similar structure in texture, showed the same rate in magnitude. A very low energy of activation for the reaction, about 1 Kcal/mol was obtained in the study. The influence of water vapor concentration on the reaction rate was scarcely observed in the concentrations used in this experiment. Contribution of the radiation induced reaction rate to whole reaction rate at 10000C was discussed. (author)

  1. Chromatographical profiles of fluid extracts and tinctures obtained from Mikania glomerata Sprengel sterilized by gamma ray irradiation

    Scientific Electronic Library Online (English)

    Carlos Augusto F., Peregrino; Suzana G., Leitão.

    2005-09-01

    Full Text Available Aerial parts of Mikania glomerata Sprengel, were irradiated with gamma rays in an apparatus with a Cesius-137 source in two different doses: 3.5 and 5.0 KGy. Double-blind HPLC studies on fluid extracts and tinctures prepared from the irradiated drug material were utilized to verify possible chemical [...] changes. Extracts from the same plant (untreated) were used as standards. The results obtained showed that there was an increase in the coumarin content in the extracts obtained from irradiated plants (3.5 and 5.0 KGy) as well as a decrease in the o-coumaric acid concentration.

  2. Measuring of hands irradiation by gamma-ray and positron of personnel of the departments of nuclear medicine by TL dosimetry

    International Nuclear Information System (INIS)

    The authors carried out measurement of hands irradiation by gamma-ray and positron of personnel of the departments of nuclear medicine by TL dosimetry. It was found that the estimated radiation doses are underestimated.

  3. Nondestructive burnup verification by gamma-ray spectroscopy of LEU silicide fuel plates irradiated in the RSG GAS multipurpose reactor

    International Nuclear Information System (INIS)

    Highlights: ? Nondestructive burnup verification by gamma-ray spectroscopy of LEU silicide fuel. ? The burnup of two fuel plates irradiated in the Indonesian RSG GAS was measured. ? Cs-134/Cs-137 gamma-ray activity ratio was taken as the burnup indicator. ? Burnup verification was conducted using SRAC2006 and JENDL-3.3 based library. ? An excellent agreement between the calculated and measured values was confirmed. - Abstract: Nondestructive burnup verification by gamma-ray spectroscopy of two LEU silicide fuel plates, irradiated in the Indonesian RSG GAS multipurpose reactor, has been successfully conducted. The two fuel plates, one from the central part and another from the outer part, were extracted from the in-house manufactured, experimental silicide fuel assembly which had a declared burnup level of approximately 50% loss of U-235. As a burnup indicator, the Cs-134/Cs-137 activity ratio was selected and measured to obtain the axial distribution of relative burnup, its average values, burnup peak values and peak locations for each fuel plate, as well as the burnup difference between central and outer plates. A detail depletion analysis using SRAC2006 code system and JENDL-3.3 based library was conducted to obtain the Cs-134/Cs-137 activity ratio based on the irradiation history of the fuel element. An excellent agreement between the calculated and measured values of the activity ratio was confirmed

  4. Comparison of gamma ray and electron beam irradiation on extraction yield, morphological and antioxidant properties of polysaccharides from tamarind seed

    International Nuclear Information System (INIS)

    Tamarind (Tamarindus indica L) seed polysaccharide (TSP) is of great important due to its various biological activities. The present investigation was carried out to compare extraction yield, morphological characteristics, average molecular weights and antioxidant activities of TSP from gamma- and electron beam (EB)-irradiated tamarind kernel powder. The tamarind kernel powder was irradiated with 0, 5 and 10 kGy by gamma ray (GR) and electron beam, respectively. The extraction yield of TSP was increased significantly by EB and GR irradiation, but there was no significant difference between irradiation types. Morphological studies by scanning electron microscope showed that TSP from GR-irradiated tamarind seed had a fibrous structure, different from that of EB irradiated with a particle structures. The average molecular weight of TSP was decreased by the irradiation, and EB treatment degraded more severely than GR. Superoxide radical scavenging ability and total antioxidant capacity of EB-treated TSP showed higher than those of GR-treated TSP.

  5. Quality of gamma ray-irradiated iceberg lettuce and treatments to minimize irradiation-induced disorders

    Science.gov (United States)

    Irradiation of Iceberg lettuce was recently approved by the FDA to enhance microbial safety and to extend shelf-life at doses up to 4 kGy. However, the radiation tolerance of whole head lettuce is unclear. The present study was conducted to investigate the effects of irradiation on the quality of he...

  6. Influences of Co-60 gamma-ray irradiation on electrical characteristics of Al2O3 MOS capacitors

    International Nuclear Information System (INIS)

    Effects of gamma-ray irradiation on the electrical characteristics of Al2O3 MOS capacitors such as barrier height, acceptor concentration, series resistance and interface state parameters have been studied by analyzing capacitance-voltage (C-V) and conductance-voltage (G/?-V) measurements. The fabricated MOS capacitors were irradiated with gamma-rays at doses up to five grays. C-V and G/?-V measurements were recorded prior to and after irradiation at high frequency. The results show that the measured capacitance and conductance values decreased with increasing in irradiation dose and C-V and G/? curves has been shifted toward the negative voltages. Moreover, the series resistance (Rs) and density of interface states increased with increasing in irradiation dose and density of interface states (Dit) were calculated as order of 1012 eV-1cm-2 prior to and after irradiation. Due to presence and variations in the Rs values, the corrected and the measured C-V and G/?-V exhibited different behaviors. Therefore other electrical characteristics were assessed from corrected Cc characteristics. It was observed that acceptor concentration decreased with increasing in barrier height of device due to changes in interface states and diffusion potential. (author)

  7. The response of mouse jejunal crypt cells to Cs-137 gamma rays and Cf-252 neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Coffey, C.W.; Meece, D.; Beach, J.L.

    1986-01-01

    Male CD/sub 2/F/sub 1//HAP mice were exposed to similar doses from Cs-137 and Cf-252 linear source arrays using a ferris wheel irradiator. The Cs-137 ..gamma..-ray dose rate was 87.2 cGy/hr as determined by TLD dosimetry. A paired ionization chamber measurement technique was utilized to evaluate the Cf-252 dose rate; i.e. 14.4 cGy/hr neutron and 6.5 cGy/hr gamma rays (n/..gamma.. ratio = 2.22). Jejunal crypt scoring criteria followed those established by a previous study. These experiments show that RBE in small bowel was high using microcolony assay. Analysis of crypt survival curves yielded a RBE for Cf-252 neutrons of approximately 6.0 for small bowel in agreement with data reported by the earlier study.

  8. Production of acetic acid from ethanol solution by acetobactor acetigenum and effect of gamma-ray irradiation on the bacteria

    International Nuclear Information System (INIS)

    A preliminary study on fermentation of acetic acid by S. cerevisiae and A. acetigenum was carried out to obtain information to develop the effective utilization technology of agricultural liquid wastes. Aqueous solutions of glucose and/or ethanol were used as a model of agricultural liquid waste. The effect of gamma-ray irradiation on A. acetigenum for enhancement of the fermentation was also examined. In this study, irradiated A. acetigenum had activity to produce acetic acid even after loss the activity to grow. (author)

  9. The effects of prenatal irradiation with a low doses of gamma-rays on spatial memory in adult rats

    International Nuclear Information System (INIS)

    Pregnant females of Wistar-strain rats were irradiated (sham-irradiated) with a dose of 1 Gy of gamma-rays on the 16th day of pregnancy. The progeny of both irradiated and control animals was tested in Morris' water maze for spatial memory at age of 4 months. The time needed to find the hidden platform and the swimming-track were recorded using a computer aided video-tracking method. The test was repeated after 24 hours (short-time memory) and after one week (long-time memory). In short-time memory test the irradiated females needed in comparison with controls a statistically significantly longer time and a longer swimming track to find the platform. No significant differences were found in male. In long-term memory test no significant differences in both parameters followed were found in either of sexes. The results suggest, that irradiation with a low dose of gamma-rays during the period of the embryonic development of the brain can negatively influence the short-term spatial memory, but has no effect on long-time memory in rats. (authors)

  10. Radiation induced changes in electrical conductivity of chemical vapor deposited silicon carbides under fast neutron and gamma-ray irradiations

    International Nuclear Information System (INIS)

    The radiation-induced changes in the volume electrical conductivities of chemical vapor deposited silicon carbides (CVD-SiCs) were in-site investigated by performing irradiation using 1.17 and 1.33-MeV gamma-ray and 14-MeV fast neutron beams in air and vacuum. Under gamma-ray irradiation at ionization dose rates of 3.6 and 5.9 Gy/s and irradiation temperature of approximately 300 K, the initial rapid increase in electrical conductivity; this is indicative of radiation-induced conductivity (RIC), occurred due to electronic excitation, and a more gradual increase followed up to a dose of approximately 10-50 kGy corresponding to the results in base conductivity without radiation; this is indicative of radiation-induced electrical degradation (RIED). However, the radiation-induced phenomena were not observed at irradiation temperatures above 373 K. Under neutron irradiation at a further low dose rate below approximately 2.1 Gy/s, a fast neutron flux of 9.2 x 1014 n/m2 s, and 300 K, the RIED-like behavior according to radiation-induced modification of the electrical property occurred with essentially no displacement damage, but ionizing effects (radiolysis).

  11. Dense electron-positron plasmas and ultra intense gamma rays from laser-irradiated solids

    International Nuclear Information System (INIS)

    In simulations of a 10 PW laser striking a solid, we demonstrate the possibility of producing a pure electron-positron plasma by the same processes as those thought to operate in high-energy astrophysical environments. A maximum positron density of 1026 m-3 can be achieved, 7 orders of magnitude greater than achieved in previous experiments. Additionally, 35% of the laser energy is converted to a burst of gamma rays of intensity 1022 W cm-2, potentially the most intense gamma-ray source available in the laboratory. This absorption results in a strong feedback between both pair and gamma-ray production and classical plasma physics in the new 'QED-plasma' regime. (authors)

  12. Radiosensitivity of apricot budsticks exposed to acute gamma rays and nursery observations on the second vegetative generation from irradiated buds

    International Nuclear Information System (INIS)

    Varietal improvement is essential if a new impetus is to be given to the French apricot crop. We have accordingly started a mutation breeding programme by bud irradiation. Because of the scarcity of bibliographical data, the first step was to study the budwood radiosensitivity of the apricot cultivars used as starting material. Budsticks of various cultivars were exposed to increasing doses of acute gamma rays. The physiological effects induced by irradiation were evaluated from bud survival and growth. These results allowed us, in the first instance, to fix the optimal dose range for dormant buds irradiated at 6 to 7 Gy/mm. Observations in the nursery on scions from the second vegetative generation (V2) already showed the limits of bud irradiation. Further observations in the orchard are need to estimate the value of this method for apricot breeding

  13. Preliminary research on death pattern in PC12 cell after high-dose of gamma-ray irradiation

    International Nuclear Information System (INIS)

    Objective: To investigate the death pattern of pheochromocyoma cell line (PC12 cell) irradiated with ionizing radiation and to search for a model of radiation-induced neuron injury in vitro. Methods: PC12 cell was irradiated with different doses of 60Co ?-rays. The effect of radiation on cell cycle, development, differentiation and death rate were detected by flow cytometry, light microscope, and transmission electron microscope (TEM). Results: Irradiated PC12 cell showed cell cycle retardation and differentiation, but some cells died due to swelling. Apoptosis was observed in few cells. TEM examination indicated that mitochondrion and endoplasmic reticulum were dilated markedly, chromatin was concentrated and scattered near karyotheca or around the nucleolus, which characterized oncosis. Conclusions: PC12 cell died through oncosis after gamma-ray irradiation of high-dose, and can be used as a radiation-induced neuron injury model. (authors)

  14. Evaluation of induced radioactivity in 10 MeV-electron irradiated spices, (1); [gamma]-ray measurement

    Energy Technology Data Exchange (ETDEWEB)

    Furuta, Masakazu; Katayama, Tadashi; Ito, Norio; Mizohata, Akira; Matsunami, Tadao; Shibata, Setsuko; Toratani, Hirokazu (Osaka Prefectural Univ., Sakai (Japan). Research Inst. for Advanced Science and Technology); Takeda, Atsuhiko

    1994-02-01

    Black pepper, white pepper, red pepper, ginger and turmeric were irradiated with 10 MeV electrons from a linear accelerator to a dose of 100 kGy and radioactivity was measured in order to estimate induced radioactivity in the irradiated foods. Induced radioactivity could not be detected significantly by [gamma]-ray spectrometry in the irradiated samples except for spiked samples which contain some photonuclear target nuclides in the list of photonuclear reactions which could produce radioactivity below 10 MeV. From the amount of observed radioactivities of short-lived photonuclear products in the spiked samples and calculation of H[sub 50] according to ICRP Publication 30, it was concluded that the induced radioactivity and its biological effects in the 10 MeV electron-irradiated natural samples were negligible in comparison with natural radioactivity from [sup 40]K contained in the samples. (author).

  15. Genetic improvement of soybean seed proteins by {gamma}-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, Keisuke [Agriculture, Forestry and Fisheries Research Council Secretariat, MAFF, Research and Development Division (Japan)

    1998-12-31

    Although soybeans have the highest protein content among seed crops, the protein quality is poor due to the low content of the sulfur-containing amino acids, cysteine and methionine. Soybean 7S globulin and 11S globulin are the two major protein components, accounting for about 70% of the total seed protein. The 11S globulin contains three to four times more methionine and cysteine per unit protein than that of the 7S globulin. Furthermore, the two globulins show considerable differences in food processing properties such as gel-making ability and emulsifying capacity. The 7S globulin is composed of three kinds of polypeptides, designated as {alpha}, {alpha}` and {beta} subunits. A variety of soybean cv. Keburi, which lacks {alpha}` subunit was identified in a germplasm collection. An induced mutant line which lacks both {alpha} and {alpha}` subunits, was recently identified in the progeny of {gamma}-ray-irradiated seeds from a line lacking {alpha}` subunit. On the other hand, the 11S globulin is composed of the A{sub 1a}B{sub 2}, A{sub 1b}B{sub 1b}, A{sub 2}B{sub 1a}, A{sub 3}B{sub 4} and A{sub 4}A{sub 5}B{sub 3} subunits. It has become possible to breed soybeans with markedly modified protein composition from extremely high to extremely low 7S : 11S ratios using mutant genes for the subunits of the two globulins. Lipoxygenase catalyzes the hydroperoxydation of unsaturated fatty acids and polyunsaturated lipids. Soybean seeds contain three lipoxygenase isozymes, called L-1, L-2 and L-3, which are responsible for the generation of grassy-beany and bitter tastes, limiting the use of whole soybeans and soy proteins in certain food products. In the early 1980s, three types of spontaneous mutant soybean varieties lacking L-1, L-2 or L-3 were detected. Soybean cultivars having the lipoxygenase-null traits could become economically valuable for the manufacture of soy products such as soy milk due to their low levels of beany taste and their enhanced storage stability. (J.P.N.)

  16. Modifications of heterosis in hybrids between two inbred lines of maize (Zea Mays L.) irradiated with gamma rays

    International Nuclear Information System (INIS)

    A study of the effect of gamma radiation (3700 R) on heterosis in maize was carried out. Seeds of two inbred lines were irradiated with 3700R and crossed. Hybrid seeds obtained from these crossings were sown in the field according to a balanced lattice square design, 4 x 4 with 10 repetitions, and various quantitative characters were scored and analyzed. It is concluded that gamma-rays may modify combining ability o these inbred lines, accompanied by change in plant height, car number, ear length, weight of 100 kernels and husked car weight of the hybrids. (Author)

  17. Two CdZnTe detector-equipped gamma-ray spectrometers for attribute measurements on irradiated nuclear fuel

    International Nuclear Information System (INIS)

    Some United States Department of Energy-owned spent fuel elements from foreign research reactors (FRRs) are presently being shipped from the reactor location to the US for storage at the Idaho National Engineering and Environmental Laboratory (INEEL). Two cadmium zinc telluride detector-based gamma-ray spectrometers have been developed to confirm the irradiation status of these fuels. One spectrometer is configured to operate underwater in the spent fuel pool of the shipping location, while the other is configured to interrogate elements on receipt in the dry transfer cell at the INEEL's Interim Fuel Storage Facility (IFSF) Both units have been operationally tested at the INEEL. (author)

  18. Two CdZnTe Detector-Equipped Gamma-ray Spectrometers for Attribute Measurements on Irradiated Nuclear Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Hartwell, John Kelvin; Winston, Philip Lon; Marts, Donna Jeanne; Moore-McAteer, Lisa Dawn; Taylor, Steven Cheney

    2003-04-01

    Some United States Department of Energy-owned spent fuel elements from foreign research reactors (FRRs) are presently being shipped from the reactor location to the US for storage at the Idaho National Engineering and Environmental Laboratory (INEEL). Two cadmium zinc telluride detector-based gamma-ray spectrometers have been developed to confirm the irradiation status of these fuels. One spectrometer is configured to operate underwater in the spent fuel pool of the shipping location, while the other is configured to interrogate elements on receipt in the dry transfer cell at the INEEL’s Interim Fuel Storage Facility (IFSF). Both units have been operationally tested at the INEEL.

  19. Dwarf Rice Mutant Derived from 0.2 kGy Gamma Rays Irradiated Seeds of Atomita 4 Variety

    International Nuclear Information System (INIS)

    Dwarf rice mutant was obtained when Atomita 4 seeds were irradiated by 0.2 kGy gamma rays. The results of segregation analyses in F2 populations and F3 lines derived from reciprocal crosses of mutant and Atomita 4 suggested that the dwarf was controlled by a single recessive gene. This gene was not located on rice cytoplasmic genome but on nuclear genome. The gene for dwarf obtained in this study tentatively could be assumed as a new finding until the allelic relationships with other dwarf genes are verified. (author)

  20. The influence of gamma rays irradiation on chlorophyll mutation and genetic variability of agronomic characters in soybean plant

    International Nuclear Information System (INIS)

    Seeds of soybean mutant line No. 13/PsJ with 12% moisture content were irradiated by 0,10;0,20;0.30 and 0.40 kGy of gamma rays treatment. Number of irradiated seed for each treatment was 1500 seeds. Irradiated of seeds were planted in the 4m X 5m plot size with 0,20m x 0,40m spacing and two seed each hole and were planted as M-1 plants in the wet season of 1996/1997 at PAIR field experiment in Pasar Jumat, Jakarta. The experiment was designed Randomized Block Design with three replication Plans of M-1 generation were harvested individuality and were planted as known M2 plants in the next generation in dry season of 1997 at PAIR field experiment. Seven days planting the chlorophyll mutation of plants were recorded by Frydenberg method and the genetic variability of plant height, number of fertile pods and nodes were calculated by Singh and Chaudhary formula. Results of the experiment showed that chlorophyll mutation and genetic variability of plant height and number of fertile pods could be improved be 0.10 and 0,20 kGy of gamma rays treatment. (authors)

  1. Identification of gamma-ray irradiated medicinal herbs using pulsed photostimulated luminescence, thermoluminescence, and electron spin resonance spectroscopy.

    Science.gov (United States)

    Pal, Sukdeb; Kim, Byeong Keun; Kim, Won Young; Kim, Min Jung; Ki, Hyeon A; Lee, Kyeong-Hee; Kang, Woo Suk; Kang, In Ho; Kang, Shin Jung; Song, Joon Myong

    2009-08-01

    Dried herbal samples consisting of root, rhizome, cortex, fruit, peel, flower, spike, ramulus, folium, and whole plant of 20 different medicinal herbs were investigated using pulsed photostimulated luminescence (PPSL), thermoluminescence (TL), and electron spin resonance spectroscopy (ESR) to identify gamma-ray irradiation treatment. Samples were irradiated at 0-50 kGy using a 60Co irradiator. PPSL measurement was applied as a rapid screening method. Control samples of 19 different herbs had photon counts less than the lower threshold value (700 counts 60 s(-1)). The photon counts of non-irradiated clematidis radix and irradiated evodia and gardenia fruits were between the lower and upper threshold values (700-5,000 counts 60 s(-1)). TL ratios, i.e., integrated areas of the first glow (TL1)/the second glow (TL2), were found to be less than 0.1 in all non-irradiated samples and higher than 0.1 in irradiated ones providing definite proof of radiation treatment. ESR spectroscopy was applied as an alternative rapid method. In most of the irradiated samples, mainly radiation-induced cellulosic, sugar, and relatively complicated carbohydrate radical ESR signals were detected. No radiation-specific ESR signal, except one intense singlet, was observed for irradiated scrophularia and scutellaria root and artemisiae argyi folium. PMID:19529925

  2. Thermal, tensile and rheological properties of high density polyethylene (HDPE) processed and irradiated by gamma-ray in different atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Ferreto, H. F. R., E-mail: hferreto@ipen.br, E-mail: ana-feitoza@yahoo.com.br; Oliveira, A. C. F., E-mail: hferreto@ipen.br, E-mail: ana-feitoza@yahoo.com.br; Parra, D. F., E-mail: dfparra@ipen.br, E-mail: ablugao@ipen.br; Lugão, A. B., E-mail: dfparra@ipen.br, E-mail: ablugao@ipen.br [Center of Chemistry and Environment, Institute of Energy and Nuclear Research - IPEN (Brazil); Gaia, R., E-mail: renan-gaia7@hotmail.com [Faculdades Oswaldo Cruz (Brazil)

    2014-05-15

    The aim of this paper is to investigate structural changes of high density polyethylene (HDPE) modified by ionizing radiation (gamma rays) in different atmospheres. The gamma radiation process for modification of commercial polymers is a widely applied technique to promote new physical-chemical and mechanical properties. Gamma irradiation originates free radicals which can induce chain scission or recombination, providing its annihilation, branching or crosslinking. This polymer was irradiated with gamma source of {sup 60}Co at doses of 5, 10, 20, 50 or 100 kGy at a dose rate of 5 kGy/h. The changes in molecular structure of HDPE, after gamma irradiations were evaluated using thermogravimetric analysis (TGA) and tensile machine and oscillatory rheology. The results showed the variations of the properties depending on the dose at each atmosphere.

  3. Thermal, tensile and rheological properties of high density polyethylene (HDPE) processed and irradiated by gamma-ray in different atmospheres

    International Nuclear Information System (INIS)

    The aim of this paper is to investigate structural changes of high density polyethylene (HDPE) modified by ionizing radiation (gamma rays) in different atmospheres. The gamma radiation process for modification of commercial polymers is a widely applied technique to promote new physical-chemical and mechanical properties. Gamma irradiation originates free radicals which can induce chain scission or recombination, providing its annihilation, branching or crosslinking. This polymer was irradiated with gamma source of 60Co at doses of 5, 10, 20, 50 or 100 kGy at a dose rate of 5 kGy/h. The changes in molecular structure of HDPE, after gamma irradiations were evaluated using thermogravimetric analysis (TGA) and tensile machine and oscillatory rheology. The results showed the variations of the properties depending on the dose at each atmosphere

  4. Tuning the grade of graphene: Gamma ray irradiation of free-standing graphene oxide films in gaseous phase

    Science.gov (United States)

    Dumée, Ludovic F.; Feng, Chunfang; He, Li; Allioux, Francois-Marie; Yi, Zhifeng; Gao, Weimin; Banos, Connie; Davies, Justin B.; Kong, Lingxue

    2014-12-01

    A direct approach to functionalize and reduce pre-shaped graphene oxide 3D architectures is demonstrated by gamma ray irradiation in gaseous phase under analytical grade air, N2 or H2. The formation of radicals upon gamma ray irradiation is shown to lead to surface functionalization of the graphene oxide sheets. The reduction degree of graphene oxide, which can be controlled through varying the ?-ray total dose irradiation, leads to the synthesis of highly crystalline and near defect-free graphene based materials. The crystalline structure of the graphene oxide and ?-ray reduced graphene oxide was investigated by x-ray diffraction and Raman spectroscopy. The results reveal no noticeable changes in the size of sp2 graphitic structures for the range of tested gases and total exposure doses suggesting that the irradiation in gaseous phase does not damage the graphene crystalline domains. As confirmed by X-ray photoemission spectroscopy, the C/O ratio of ?-ray reduced graphene oxide is increasing from 2.37 for graphene oxide to 6.25 upon irradiation in hydrogen gas. The removal of oxygen atoms with this reduction process in hydrogen results in a sharp 400 times increase of the electrical conductivity of ?-ray reduced graphene oxide from 0.05 S cm-1 to as high as 23 S cm-1. A significant increase of the contact angle of the ?-ray reduced graphene oxide bucky-papers and weakened oxygen rich groups characteristic peaks across the Fourier transform infrared spectra further illustrate the efficacy of the ?-ray reduction process. A mechanism correlating the interaction between hydrogen radicals formed upon ?-ray irradiation of hydrogen gas and the oxygen rich groups on the surface of the graphene oxide bucky-papers is proposed, in order to contribute to the synthesis of reduced graphene materials through solution-free chemistry routes.

  5. Monte Carlo simulation of prompt gamma-ray spectra from depleted uranium under D-T neutron irradiation and electron recoil spectra in a liquid scintillator detector

    CERN Document Server

    Qin, Jianguo; Liu, Rong; Zhu, Tonghua; Zhang, Xinwei; Ye, Bangjiao

    2015-01-01

    To overcome the problem of inefficient computing time and unreliable results in MCNP5 calculation, a two-step method is adopted to calculate the energy deposition of prompt gamma-rays in detectors for depleted uranium spherical shells under D-T neutrons irradiation. In the first step, the gamma-ray spectrum for energy below 7 MeV is calculated by MCNP5 code; secondly, the electron recoil spectrum in a BC501A liquid scintillator detector is simulated based on EGSnrc Monte Carlo Code with the gamma-ray spectrum from the first step as input. The comparison of calculated results with experimental ones shows that the simulations agree well with experiment in the energy region 0.4-3 MeV for the prompt gamma-ray spectrum and below 4 MeVee for the electron recoil spectrum. The reliability of the two-step method in this work is validated.

  6. Comparative study on hematopoietic damage of mice caused by high-dose of gamma-ray irradiation

    International Nuclear Information System (INIS)

    Objective: To study the effect of high-dose of gamma-ray irradiation on hematopoiesis injury and recovery of IRM-2 and C57BL/6 J mouse. Methods: The experiment was designed to study the effects of radiation (4 Gy) on spleen index, CFU-S and DNA damage on the 9 th day of IRM-2 and ICR mice and the effects of radiation (6 Gy) on WBC change and its absolute value on the 45 th days of IRM-2 and C57BL/6 J mice. Results: The IRM-2 mouse spleen index, CFU-S and DNA were higher than ICR mouse on the 9 th days, and there were significant difference in CFU-S and DNA (P<0.01). The IRM-2 mouse WBC, RMC, HGB and HCT were higher than C57BL/6 J mouse on the 45 th days, and there were significant difference (P<0.01). Conclusion: IRM-2 mouse hematopoiesis resumes quicker than C57BL/6 J and ICR do after high-dose of gamma-ray irradiation. (authors)

  7. Mutation induction by gamma-rays and carbon ion beam irradiation in banana (Musa spp.): a study with an emphasis on the response to Black sigatoka disease

    International Nuclear Information System (INIS)

    Gamma-rays and carbon ion beam irradiation methods were applied to study critical doses, genetic variability and the response to Black sigatoka disease. 'Cavendish Enano', 'Williams', 'Orito' and 'FHIA-01' cultivars of banana were studied. Both gamma-rays and carbon ion beam irradiation methods had different biological effects when banana explants were exposed to them. In both methods, increased dose caused increased mortality. 'FHIA-01' tolerated high doses of gamma-rays but was susceptible to high doses of carbon ion beam irradiation. The results suggest that the response in 'FHIA-01' can be explored using other dose intervals between 150 and 300 Gy. Weight and height were also reduced drastically when high doses of gamma-rays and carbon ion beams were applied. The LD50 of cultivars 'FHIA-01' and 'Orito' revealed high sensitivity to both gamma-rays and carbon ion beams. DNA deletion in 'FHIA-01' occurred by using gamma-rays at doses of 200 and 300 Gy, suggesting that 'FHIA-01' is definitely a promising cultivar with a high sensitivity response to gamma-ray exposure, and that there is a high chance of improving its fruit quality by mutation induction. Sigmoid drooping leaf, a putative mutation of 'FHIA-01', was generated. This mutation is heritable as mother plant and sucker showed the same characteristics. Future research could be conducted on the relationship of leaf shape to fruit quality and production. Hexaploid cells were detected by flow cytometry (five plantsre detected by flow cytometry (five plants in 'Cavendish Enano' and one in 'Williams'), signifying that chromosome duplication can be induced by carbon ion beams. Variation in the leaves such as being abnormal, double, long, rudimentary, spindled and yellow spotted leaf was visible, suggesting that long-term chronic irradiation (gamma-rays) directly affects active cell division at the meristem level, resulting in severe damage or even death of the meristems. During the juglone toxin experiment on gamma-ray-irradiated plants, 20 plants were selected from the 'Orito' lot, eight in 'Williams' and five in 'Cavendish Enano'. In the carbon ion beam experiments, six plants of 'Williams' and two of 'Cavendish Enano' were selected as possible candidates with a better response to Black sigatoka disease. In addition, following irradiation with a carbon ion beam, a fast growing plant was observed and selected as earliness is an important characteristic for shortening the crop life cycle. Finally, field experiments throughout the whole plant cycle are needed to evaluate mutated traits for fruit quality, yield and post-harvest characteristics for a final selection. (author)

  8. Correlation between release of deuterium and annihilation of irradiation defects produced by gamma-ray in Li{sub 2}TiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Toda, Kensuke, E-mail: r0233019@ipc.shizuoka.ac.jp [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Shizuoka (Japan); Kobayashi, Makoto; Fujishima, Tetsuo; Uchimura, Hiromichi; Miura, Ryo [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Shizuoka (Japan); Fujii, Toshiyuki; Yamana, Hajimu [Research Reactor Institute, Kyoto University, Kumatori (Japan); Oya, Yasuhisa; Okuno, Kenji [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Shizuoka (Japan)

    2013-10-15

    The dependence of irradiation defect density on hydrogen isotope release behaviors in Li{sub 2}TiO{sub 3} was studied. Li{sub 2}TiO{sub 3} was exposed to gaseous deuterium and, thereafter, gamma-ray irradiation was performed with various gamma-ray doses to change the density of irradiation defects. The deuterium release behavior was measured by TDS. The density of the defects and the state of O-D bonds in the sample were elucidated by ESR and FT-IR, respectively. Most of deuterium was adsorbed on the surface or trapped by intrinsic defects after deuterium gas exposure. However, O-D bonds were increased as the gamma-ray dose was increased. In addition, the irradiation defects like E-center, O{sup ?}-center and O{sub 2}{sup ?}-center were observed in gamma-ray irradiated samples. This indicated that the density of irradiation defect control the deuterium stable trapping by oxygen. These facts conclude that tritium release temperature will be shifted toward higher temperature as the operation time increased and irradiation defects are accumulated.

  9. Biodegradation polyurethane derived from vegetable oil irradiated with gamma rays 25 kGy and 100 kGy

    International Nuclear Information System (INIS)

    The environment requires polymers that can be degraded by the action of microorganisms. In this work was studied the biodegradation of polyurethane samples derived from vegetable oil (castor oil), which were irradiated with gamma rays 25 kGy and 100 kGy compared with the same polyurethane without being irradiated. Biodegradation of polyurethane was carried out in culture medium containing the fungus Aspergillus niger by 146 days and the result was evaluated using the technique of thermogravimetric analysis, where there was a change of behavior of the curves TGA / DTG occurred indicating that chemical modifications of molecules present in the structure of the polymer chain, thus confirming that the material has undergone the action of microorganisms. (author)

  10. On-Line High Dose-Rate Gamma Ray Irradiation Test of the CCD/CMOS Cameras

    International Nuclear Information System (INIS)

    In this paper, test results of gamma ray irradiation to CCD/CMOS cameras are described. From the CAMS (containment atmospheric monitoring system) data of Fukushima Dai-ichi nuclear power plant station, we found out that the gamma ray dose-rate when the hydrogen explosion occurred in nuclear reactors 1?3 is about 160 Gy/h. If assumed that the emergency response robot for the management of severe accident of the nuclear power plant has been sent into the reactor area to grasp the inside situation of reactor building and to take precautionary measures against releasing radioactive materials, the CCD/CMOS cameras, which are loaded with the robot, serve as eye of the emergency response robot. In the case of the Japanese Quince robot system, which was sent to carry out investigating the unit 2 reactor building refueling floor situation, 7 CCD/CMOS cameras are used. 2 CCD cameras of Quince robot are used for the forward and backward monitoring of the surroundings during navigation. And 2 CCD (or CMOS) cameras are used for monitoring the status of front-end and back-end motion mechanics such as flippers and crawlers. A CCD camera with wide field of view optics is used for monitoring the status of the communication (VDSL) cable reel. And another 2 CCD cameras are assigned for reading the indication value of the radiation dosimeter and the instrument. In the preceding assumptions, a major problem which arises when dealing with CCD/CMOS cameras in the severe accident situationcameras in the severe accident situations of the nuclear power plant is the presence of high dose-rate gamma irradiation fields. In the case of the DBA (design basis accident) situations of the nuclear power plant, in order to use a CCD/CMOS camera as an ad-hoc monitoring unit in the vicinity of high radioactivity structures and components of the nuclear reactor area, a robust survivability of this camera in such intense gamma-radiation fields therefore should be verified. The CCD/CMOS cameras of various types were gamma irradiated at a dose rate of about 150 Gy/h till these cameras failed. A high dose-rate gamma ray radiation induced speckles in the camera image were heavily observed. In this paper we describe the evolution of their basic characteristics with high dose rate gamma irradiation and shortly explain the observed phenomena

  11. Investigations on the degradation, of visible laser diodes under, gamma-ray irradiation

    International Nuclear Information System (INIS)

    The possible use of semiconductor optoelectronic devices (laser diodes, light emitting diodes, photodetectors) as component parts of remote sensing and diagnostics systems, for different robotic setups in nuclear equipment or for optical fiber-based communication led to the intensive investigations of these components as they operate in radiation environment. We report our research on the evaluation of the gamma-ray induced degradation of several semiconductor laser diodes, emitting at three visible wavelengths, in order to make a preliminary assessment for their possible use in fusion installations

  12. Induction of mutant resistant to alternaria blotch of apple by gamma-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshioka, Toji [Hokuriku National Agricultural Experiment Station, Joetsu, Niigata (Japan); Ito, Yuji [National Inst. of Agrobiological Resources, Tsukuba, Ibaraki (Japan); Masuda, Tetsuo [National Institute of Fruit Tree Science, Morioka, Iwate (Japan)

    2000-07-01

    Apple cultivars resistant to Alternaria blotch disease have been produced by cross-breeding, but it is difficult to produce resistance by crossing without changing the properties of cultivar because the gene composition of the cultivar tree is almost heterozygous. This study aimed to investigate the resistant mutation in Alternaria blotch susceptible and semiresistant cultivars. The resistance to Alternaria blotch pathogen or AM toxin is classified into the following three groups: 1) highly sensitive group including Indo, Redgold and Starking delicious, 2) semi-resistant group including Fuji, Orin and Golden delicious and 3) resistant group including Gala and Tsugaru. After gamma ray exposure of 80 Gy (at 5 Gy/hour), AM-toxin insensitive clones were selected in the VM{sub 6} generation. These selected mutants could be rooted and habituated under field conditions. The degree of disease resistance was assessed by AM toxin treatment and Alternaria blotch fungi spore inoculation test. The leaves of these mutants were changed to variegated at high temperature, suggesting that some mutation related to chloroplast might have occurred. Alternaria blotch resistant strains could be produced by exposing to {gamma}ray and selecting with AM toxin in shoot-tip culture system, but the functional effects of the AM toxin in Alternaria blotch and also the mechanism in the mutant lines were still unclear. (M.N.)

  13. New method for the estimation of the mutation rate in acute and chronic gamma-ray irradiation of growing plants

    International Nuclear Information System (INIS)

    In the case of irradiation of seeds of self-pollinated and disomic plant materials, the frequency of mutated plants appearing in the M2 generation divided by the Mendelian ratio is an index, as proposed by Gaul (1960), that enables the direct estimation of the mutation rate, representing the ratio of the number of mutated cells to the number of survived cells after treatment of mutagen. In the case of chronic irradiation of growing plants throughout the entire life cycle from germination to maturity, on the other hand, the mutations induced at the stage preceding the differentiation of the male and female organs appear at the M2 generation, the but mutations induced after this critical time are observed in the M2 plants in the heterozygous condition and are detected only at the M3 generation. Therefore, the mutation rate can not be correctly estimated only on the basis of the frequency of mutants either in the M2 or M3 generation. A new method for the estimation of the mutation rate by combining the data of the frequency of mutants and the M2 and M3 generation, which is comparable to Gaul's method for seed irradiation, is proposed. Application of this method to the data of acute and chronic gamma-ray irradiation of growing barley revealed that a much higher mutation rate was observed after irradiation at a higher daily exposure rate, when the plants were treated with the same accumulated dose

  14. Fabrication and characterization of monodisperse zinc sulfide hollow spheres by gamma-ray irradiation using PSMA spheres as templates

    Science.gov (United States)

    Zhao, Yongbin; Chen, Tiantian; Zou, Jianhua; Shi, Wenfang

    2005-03-01

    The submicrometer monodisperse zinc sulfide (ZnS) hollow spheres were synthesized by gamma-ray irradiation at room temperature, using monodisperse poly (styrene-methyl methacrylate-acrylic acid) (PSMA) latex spheres as the templates. X-ray diffraction (XRD) spectroscopy, transmission electron microscopy, thermogravimetric analysis, and UV-vis spectroscopy were used to characterize these nanoparticles, indicating the formation of core-shell colloidal spheres, as well as hollow spheres. The TEM study for the ZnS-coated PSMA core-shell particles has revealed the uniform coating of ZnS on the PSMA core surface as a thin layer. The obtained ZnS hollow spheres are uniform having a diameter range of 365-375 nm, and wall thickness range of 25-35 nm.

  15. Mechanical Properties of Organic Materials Used in Superconducting Magnets Irradiated by Gamma Rays at Liquid Nitrogen Temperature

    International Nuclear Information System (INIS)

    Radiation resistance of organic materials used in superconducting magnets for a 50 GeV-750 kW proton beam line for the J-PARC neutrino experiment was studied with respect to mechanical properties. Specimens cooled at a liquid nitrogen temperature of 77 K were irradiated by gamma rays from 60Co with the maximum dose beyond 10 MGy. The flexural strength of glass-fiber reinforced plastics (GFRPs), the tear strength of polyimide films and the tensile lap-shear strength of adhesive films were evaluated. It was verified that the organic materials used in the superconducting magnets have the sufficient radiation resistance, and the degradation of their mechanical properties after the 10 years operation was estimated to be negligible

  16. Stimulating effect of space flight factors on Artemia cysts: comparison with irradiation by gamma rays

    International Nuclear Information System (INIS)

    The Artemia cyst, a gastrula in dormant state, is a very suitable material to investigate the individual effects of HZE cosmic particles. Monolayers of Artemia cysts, sandwiched with nuclear emulsions, flew aboard the Soviet biosatellite Cosmos 1129. The space flight stimulated the developmental capacity expressed by higher percentages of emergence, hatching, and alive nauplii at day 4-5. A greater mean life span was reported in Artemias developed from Artemia cysts hit by the cosmic heavy ions. On Earth, Artemia cysts were exposed to 1, 10, 100, 200 and 400 Gy of gamma (gamma) rays. A stimulating effect on developmental capacity was observed for 10 Gy; the mean life span was significantly increased for this dose. These results are discussed in comparison with previous investigations performed on Earth and in space

  17. Effects of the gamma-ray irradiation on the optical absorption of pure silica core single-mode fibres in the visible and NIR range

    International Nuclear Information System (INIS)

    Optical absorption induced by photon radiation was evaluated for several commercial pure silica core, single mode, optical fibres. The study was performed for three different wavelengths: 630, 670 and 785 nm. We have identified a fibre whose induced transmission loss stays below 1 dB/m after 300 kGy gamma-ray irradiation

  18. Effects of gamma-rays irradiation in seed of mungbean (vigna radiata (L.) wilczek) composition of media on shoot regeneration of explants from node of cotyledon

    International Nuclear Information System (INIS)

    Study the effects of gamma-rays irradiation and composition and media on shoot regeneration of explants from node of cotyledon of mungbean. Wallet variety have been conducted. The explants derived of irradiated seeds of 10-20 Gy of gamma rays were planted in the 0.7% agar solution. One day after planting in the agar media the embryo axis of germinate seed were removed and the node of cotyledon were cultured in the regeneration media as examples. The results shown that shoot regeneration was influenced by media composition and the doses of gamma rays irradiation in seed. In the MURASHIGE and SKOOG medium which contain of BAP or 2-iP or Kinetin with 3 ppm concentrate respectively the explants could produced 100% of shoots. However, the highest. number of produced shoot (3 shoots) was showed in the medium which contained of BAP. The medium with I ppm concentrate od BAP could produced 100% shoot regeneration and the maximum number of shoots (4 shoots) per explant was showed in with 5 ppm. concentrate of BAP. The effectivity off BAP for shoot regeneration by enrichment of 12 ppm Ag2SO4 in the media. Irradiation of 10-20 Gy gamma rays on seeds of mungbean walet variety could improved shoot regeneration of explants from node cotyledon. (author)

  19. Monte Carlo simulation of prompt gamma-ray spectra from depleted uranium under D-T neutron irradiation and electron recoil spectra in a liquid scintillator detector

    OpenAIRE

    Qin, Jianguo; Lai, Caifeng; Liu, Rong; Zhu, Tonghua; Zhang, Xinwei; Ye, BangJiao

    2015-01-01

    To overcome the problem of inefficient computing time and unreliable results in MCNP5 calculation, a two-step method is adopted to calculate the energy deposition of prompt gamma-rays in detectors for depleted uranium spherical shells under D-T neutrons irradiation. In the first step, the gamma-ray spectrum for energy below 7 MeV is calculated by MCNP5 code; secondly, the electron recoil spectrum in a BC501A liquid scintillator detector is simulated based on EGSnrc Monte Car...

  20. Culture competency and regeneration capacity of rice (oryza sativa) embryogenic callus after irradiation with 60Co gamma rays

    International Nuclear Information System (INIS)

    The aims of this investigation are to prove the applying of a combination consequence, in vitro somatic embryogenesis induction and irradiation. Three main point were focused. callus formation from irradiated mature embryos, effect of gamma radiation on the growth of embryogenic and the interaction between gamma rays effects and embryogenic calli sizes on regeneration rate. Callus size was classified in this study in three groups. The first white color (> 1.0 mm), less than normal size. The second (1-2 mm ) just reached the normal size, yellowish green color, from which fully regenerated plants were mainly derived and usually produced multiple shoots. The third group was more than normal (5 mm ) in size, yellow green to light green in color, these larger Calli did not regenerate but became rhizogenic and necrotic. The relationship between the larger callus size and plant regeneration ability could be due to that the large calluses are old, with lesser cellular activity. The highest callus induction rate from irradiated mature embryos was found at 20-40 Gy, also higher than non-irradiated embryos. Higher doses of gamma irradiation on callus induction effected a poor response, mature embryos exposited to 60 Gy and non-irradiated callus achieved the lowest callus induction. Callus forming roots ( % rhizogenic callus) was not significantly differed by increased radiation dosage. An increase in callus fresh and dry weight was materialized by an increase in dose from 20-terialized by an increase in dose from 20-40 Gy than non-irradiated by a decrease in callus and dry weight at 60 Gy. When embryogenic callus grew, green spots began to differentiate and green shoots started to develop respectively

  1. Concentration of Proteins and Protein Fractions in Blood Plasma of Chickens Hatched from Eggs Irradiated with Low Level Gamma Rays

    International Nuclear Information System (INIS)

    In literature there are many results which have shown that low dose radiation can stimulate many physiological processes of living organism. In our earlier paper it was shown that low dose of gamma radiation has a stimulative effect upon metabolic process in chickens hatched from eggs irradiated before incubation. This was proved by increase of body weight gain and body weight, as well as by increase of two enzymes activities in blood plasma (aspartate aminotransferase and alanine aminotransferase) which play an important role in protein metabolism. Therefore, an attempt was made to determine the effect of eggs irradiation by low dose gamma rays upon concentration of total proteins and protein fractions in the blood plasma of chickens hatched from irradiated eggs. The eggs of heavy breed chickens were irradiated with a dose of 0.15 Gy gamma radiation (60Co) before incubation. Along with the chickens which were hatched from irradiated eggs, there was a control group of chickens hatched from nonirradiated eggs. All other conditions were the same for both groups of chickens. Blood samples were taken from the right jugular vein on the 1st and 3rd day, or from the wing vein on days 5 and 7 after hatching. The total proteins concentration in the blood plasma was determined by the biuret method using Boehringer Mannheim GmbH optimized kits. The protein fractions (albumin, ?1-globulin, ?2-globulin, ?- and ?-globulins) were estimated electrophoretically on Cellogel strips. The total proteins concentration was significantly decreased in blood plasma of chickens hatched from irradiated eggs on days 3 (P th day (P 2-globulin was decreased on days 1 (P th day of life. Obtained results indicate that low dose of gamma radiation has mostly inhibitory effect upon concentration of total proteins and protein fractions in the blood plasma of chickens hatched from irradiated eggs before incubation. (author)

  2. Formation and conversion of defect centers in low water peak single mode optical fiber induced by gamma rays irradiation

    International Nuclear Information System (INIS)

    The formation and conversion processes of defect centers in low water peak single mode optical (LWPSM) fiber irradiated with gamma rays were investigated at room temperature using electron spin resonance. Germanium electron center (GEC) and self-trapped hole center (STH) occur when the fibers are irradiated with 1 and 5 kGy cumulative doses, respectively. With the increase in irradiation doses, the GEC defect centers disappear, and new defect centers such as E' centers (Si and Ge) and nonbridge oxygen hole centers (NBOHCs) generate. The generation of GEC and STH is attributed to the electron transfer, which is completely balanced. This is the main reason that radiation-induced attenuation (RIA) of the LWPSM fiber is only 10 dB/km at communication window. The new defect centers come from the conversion of GEC and STH to E' centers and NBOHC, and the conversion processes cause bond cleavage, which is the root cause that the RIA of the LWPSM fiber significantly increases up to 180 dB/km at working window. Furthermore, the concentration of new defect centers is saturated easily even by increasing cumulative doses.

  3. Transferases activity in blood plasma of chickens hatched from eggs irradiated during incubation by low dose gamma rays

    International Nuclear Information System (INIS)

    In our earlier studies chickens hatched from eggs irradiated with 0.15 Gy gamma rays before incubation showed a significantly higher growth than controls during the fattening period (1-42 days). The activity of aspartate-aminotransferase (AST), alanine-aminotransferase (ALT) and plasma glucose in the same chickens were also significantly higher. These results suggested that low-dose gamma-radiation stimulated certain metabolic processes in chickens hatched from eggs irradiated before incubation. The goal of this study was to determine the effects of low-dose ionising radiation on AST and ALT activity in the blood plasma of chickens hatched from eggs irradiated during incubation. The eggs of heavy breeding chickens (Avian, line 34) were exposed to 0.15 Gy of gamma-radiation (60Co) on the seventh day of incubation, i.e. at the time when the organogenesis in chickens is completed. The control group of chickens hatched from non-irradiated eggs. All other conditions were the same for both groups. After hatching, blood samples were taken from the wing vein on days 1, 3, 5, 7, 10, 20, 32 and 42. The activity of both enzymes was determined spectrophotometrically using Boehringer Mannheim GmbH optimised kits. On day 10, AST and ALT activity were significantly higher in the blood plasma of chickens hatched from irradiated eggs, but it significantly dropped for both enzymes on day 20. Our results indicate that exposure of eggs to low-dose gamma-radiation on the seventh day of incubation affects AST and ALT activity in the blood plasma of chickens hatched from irradiated eggs. However, this effect is somewhat different from the effects of egg exposure to low-dose gamma radiation before incubation.(author)

  4. Effect of gamma-ray irradiation on structural properties of GaAsN films grown by metal organic vapor phase epitaxy

    Science.gov (United States)

    Klangtakai, Pawinee; Sanorpim, Sakuntam; Wattanawareekul, Atiwat; Suwanyangyaun, Pattana; Srepusharawoot, Pornjuk; Onabe, Kentaro

    2015-05-01

    The effects of gamma-ray irradiation on the structural properties of GaAs1-xNx films (N concentration=1.9 and 5.1 at%) grown by metal organic vapor phase epitaxy on GaAs (001) substrates were investigated. The GaAs1-xNx films were irradiated by gamma rays with irradiation strength of 0-2.0 MGy. Scanning electron microscopy and atomic force microscopy results showed that a gamma ray with a strength of 0, 0.5, 1.0, 1.5, and 2.0 MGy formed holes with a density of 0.0, 8.8, 9.4, 11.5, and 11.9 ?m-2, respectively, on the surface of a GaAs0.981N0.019 film with low N content. On the other hand, the irradiated high-N-content GaAs0.949N0.051 film exhibited a cross-hatch pattern, which was induced by partial strain relaxation at high N levels, with a line density of 0.0, 0.21, 0.37, 0.67, and 0.26 ?m-1 corresponding to an irradiation strength of 0, 0.5, 1.0, 1.5, and 2.0 MGy, respectively. The high-resolution X-ray diffraction and Raman scattering results revealed an increase in N incorporation and strain relaxation after irradiation. In addition, the GaAs0.949N0.051 films exhibited phase separation, which took place via N out-diffusion across the interface when the irradiation strength exceeded 1.0 MGy. Based on these results, the main cause of structural change was determined to be the irradiation effects including displacement damage and gamma-ray heating.

  5. Gamma-ray-enhanced reactivation of irradiated adenovirus in Xeroderma pigmentosum and Cockayne syndrome fibroblasts

    International Nuclear Information System (INIS)

    A ?-ray-enhanced reactivation (?RER) of uv-irradiated as well as of ?-irradiated human adenovirus type 2 (Ad 2) was detected following infection of normal, Xeroderma pigmentosum (XP), and Cockayne syndrome (CS) fibroblasts that had been preirradiated with ? rays. Gamma-irradiated or nonirradiated fibroblasts were infected with either nonirradiated or irradiated Ad 2, and 48 hr after infection cells were examined for the presence of viral structural antigens (Vag) using immunofluorescent staining. Results obtained using seven different normal fibroblast strains showed that irradiation of host monolayers with 1 krad immediately prior to infection resulted in a ?RER factor +-SE of 4.5 +- 1.6 for uv-irradiated virus and 4.3 +- 1.3 for ?-irradiated virus. CS fibroblasts, as well as excision repair-deficient XP fibroblasts from complementation groups A and D, were all found to be capable of expressing ?RER of irradiated Ad 2. XP variant cells expressed lower levels of ?RER compared to most normal strains, suggesting a possible role for cellular postreplication repair in the mechanism responsible for ER in human cells. An excision-deficient XP fibroblast strain belonging to complementation group A, but derived from a patient afflicted with the severe De Sanctis-Cacchione form of XP, although proficient in ?RER of ?-irradiated Ad 2, yielded barely detectable levels of ?RER for uv-irradiated Ad 2

  6. Radiation damage of polymers studied by positron annihilation. Positron and gamma-ray irradiation effects

    International Nuclear Information System (INIS)

    Positron irradiation effects on polypropylene (PP) have been studied using positron sources (22Na) during positron annihilation (PA) experiments. The irradiation effect was measured by the intensity (I3) of the long-lived component of positronium (Ps). At a low temperature of around 100 K, I3 for unirradiated PP samples increased due to a termination of the thermal motion of the -CH3 groups. However, the increase in I3 for ?-ray irradiated samples was reduced in inverse proportion to the amount of irradiation. Although no increase in I3 was observed for 1 MGy-irradiated PP with ?-rays, an increase was observed again after a 48 h irradiation by positrons emitted from 22Na. This may be due to a reconstructing of the polymer chains. (author)

  7. Low temperature gamma ray irradiation effects on polymer materials (4)-gas analysis of GFRP and CFRP

    International Nuclear Information System (INIS)

    Gas analysis was carried out at RT after gamma-irradiation at room temperature and 77K for glass fiber reinforced plastic (GFRP) and carbon fiber reinforced plastic (CFRP) having the same epoxy resin matrix. Gas yield from CFRP was less than that from GFRP at RT, but comparable at 77 K. The yields of CO and CO2 showed a large dependence on the irradiation temperature, i.e. they were much less at 77 K. Radiation resistance of GFRP and CFRP towards 77 K irradiation is expected to be higher than that towards RT irradiation. (author)

  8. Gamma ray irradiation induced optical band gap variations in chalcogenide glasses

    International Nuclear Information System (INIS)

    In the present work ?-irradiation induced optical band gap variations (?E opt) were investigated on Ge-As-Se and Ge-As-Se-Te chalcogenide glasses. Higher doses of ?-irradiation resulted in decreased E opt, which was composition dependent. Especially, glasses with stoichiometric compositions showed different ?E opt from nonstoichiometric glasses under the same irradiation conditions. There seemed existence of a threshold E opt (TE) under the certain dose of irradiation below which ?E opt hardly occurred. Results were interpreted from viewpoint of glass structure, Chemical Bond Approach (CBA) and localized states density theory. Raman analysis supported well these discussions

  9. measurement of absorbed dose in mix-dp phantom irradiated by x and gamma rays

    International Nuclear Information System (INIS)

    It has been done of x-rays dan gamma rays absorbed dose measurement of mix-dp phantom of 70 kVp.90kvp and 110 kvp x rays kxo-12 medical exposure and cobalt-60 gamma (50 ci) by UD-170A BeO-TLD. Ionization chamber 12 cc NIRS-R2 as reference dosemeter, which was calibrated on primer dosemeter. In X-rays energy used, it was done of absorbed dose measurement on Mix-Dp phantom surface and depth (d= 10cm) beam field area 10 x 10 cm, focus distance (FSD), s=80 cm dose measurement of 90 kvp X-rays on Mix-Dp phantom surface, depth and scattering (d=15 cm) beam field area 12 x 12 cm, focus distance (FSD),s=79 cm and measurement of absorbed dose Co-60 gamma: 5 R, 10R, 20 R, 30R, 40R and 50R by dose rate 0.434 R/min. It was shown that in clinical, effective energy range of X-rays relative lower than dose range Co-60 gamma. BeO-TLD characteristic on energy dependence is low based on TI sensitivity ± 1.3 for energy below 100 keV. Relation between absorbed dose and TL response to 90 kVp X-rays shown that rperm=0.990, r ber=0.995 and r sact=0.962. In measurement of Co-60 gamma absorbed dose by BeO-TLD shown TI sensitivity decrease ± 0.900. The result still needed corrections to achieve optimum measurement of absorbed dose X-rays and gamma by UD-170A BeO-TLD, which were performed optimum fading time and anealling temperature

  10. Gamma-ray spectrometric measurements of fission rate ratios between fresh and burnt fuel following irradiation in a zero-power reactor

    International Nuclear Information System (INIS)

    The gamma-ray activity from short-lived fission products has been measured in fresh and burnt UO2 fuel samples after irradiation in a zero-power reactor. For the first time, short-lived gamma-ray activity from fresh and burnt fuel has been compared and fresh-to-burnt fuel fission rate ratios have been derived. For the measurements, well characterized fresh and burnt fuel samples, with burn-ups up to 46 GWd/t, were irradiated in the zero-power research reactor PROTEUS. Fission rate ratios were derived based on the counting of high-energy gamma-rays above 2200 keV, in order to discriminate against the high intrinsic activity of the burnt fuel. This paper presents the measured fresh-to-burnt fuel fission rate ratios based on the 142La (2542 keV), 89Rb (2570 keV), 138Cs (2640 keV) and 95Y (3576 keV) high-energy gamma-ray lines. Comparisons are made with the results of Monte Carlo modeling of the experimental configuration, carried out using the MCNPX code. The measured fission rate ratios have 1? uncertainties of 1.7–3.4%. The comparisons with calculated predictions show an agreement within 1–3?, although there appears to be a slight bias (?3%).

  11. Photoluminescence spectra of thin films containing CdSe/ZnS quantum dots irradiated by 532-nm laser radiation and gamma-rays

    International Nuclear Information System (INIS)

    We have investigated temporal behavior of the photoluminescence (PL) spectra of thin films containing CdSe/ZnS quantum dots irradiated by 532 nm laser radiation and gamma-rays. Under ?100 W/cm2 laser radiation, the PL intensity (IPL) increases with irradiation time upto about 500 s and thereafter declines linearly. The wavelength of the PL emission (?peak) exhibits a blue-shift with exposure time. Upon simultaneous irradiation by 100 W/cm2 532-nm laser, as well as 0.57 and 1.06 MeV gamma-rays, the temporal behaviors of both IPL and ?peak are significantly different; IPL increases to a saturation level, and the magnitude of the blue-shift in ?peak is reduced. We discuss possible mechanisms underlying these results

  12. EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS (REVISION 1)

    Energy Technology Data Exchange (ETDEWEB)

    Clark, E.

    2013-09-13

    Two formulations of EPDM elastomer, one substituting a UV stabilizer for the normal antioxidant in this polymer, and the other the normal formulation, were synthesized and samples of each were exposed to gamma irradiation in initially pure deuterium gas to compare their radiation stability. Stainless steel containers having rupture disks were designed for this task. After 130 MRad dose of cobalt-60 radiation in the SRNL Gamma Irradiation Facility, a significant amount of gas was created by radiolysis; however the composition indicated by mass spectroscopy indicated an unexpected increase in the total amount deuterium in both formulations. The irradiated samples retained their ductility in a bend test. No change of sample weight, dimensions, or density was observed. No change of the glass transition temperature as measured by dynamic mechanical analysis was observed, and most of the other dynamic mechanical properties remained unchanged. There appeared to be an increase in the storage modulus of the irradiated samples containing the UV stabilizer above the glass transition, which may indicate hardening of the material by radiation damage. Revision 1 adds a comparison with results of a study of tritium exposed EPDM. The amount of gas produced by the gamma irradiation was found to be equivalent to about 280 days exposure to initially pure tritium gas at one atmosphere. The glass transition temperature of the tritium exposed EPDM rose about 10 ?C. over 280 days, while no glass transition temperature change was observed for gamma irradiated EPDM. This means that gamma irradiation in deuterium cannot be used as a surrogate for tritium exposure.

  13. Gamma-ray irradiation effect on the absorption and luminescence spectra of Nd:GGG and Nd:GSGG laser crystals

    International Nuclear Information System (INIS)

    Laser crystals Nd3+:Gd3Ga5O12 (Nd:GGG) and Nd3+:Gd3Sc2Ga3O12 (Nd:GSGG) were grown by Czochralski method. The influence of gamma-ray irradiation on their absorption and luminescence spectra has been investigated. Two additional absorption (AA) bands induced by gamma-ray irradiation appear in the spectra of Nd:GGG crystal while only a very weak AA band appears for the Nd:GSGG crystal. This indicated that Nd:GSGG crystal has stronger ability to resist the color center formation by irradiation. The intensity of the excitation and emission spectra of Nd:GGG crystal decrease after the irradiation of 100 Mrad gamma-ray. In contrast, a luminescence strengthening effect was observed in Nd:GSGG crystal after exposure to the same irradiation dose. The results showed that the Nd:GSGG crystal is a promising candidate used under radiation environments such as in outer space

  14. Effects of gamma-ray irradiation on a cyanate ester/epoxy resin

    International Nuclear Information System (INIS)

    Effects of ?-ray irradiation on a cyanate ester/epoxy resin composed of dicyanate ester of bisphenol A (DCBA) and diglycidyl ether of bisphenol A (DGEBA) were investigated by changes in physicochemical and mechanical properties after the ?-ray irradiation with dose of 100 MGy as maximum at around 40 °C under vacuum. After the irradiation, gases of hydrogen, carbon monoxide and carbon dioxide were evolved, glass transition temperature decreased, and flexural strength also decreased. It was concluded that ether linkages bonded to cyanurate, isocyanurate and oxazolidinone structures are mainly decomposed by the irradiation. After 100 MGy irradiation, the flexural strength of DCBA/DGEBA was maintained more than 170 MPa which is 90% of initial value of 195 MPa. Flexural modulus and density slightly increased to the values of 3.9 GPa and 1.211 g/cm3 from initial values of 3.4 GPa and 1.199 g/cm3, respectively. - Highlights: • A cyanate ester/epoxy resin was irradiated by ?-rays with dose of 100 MGy in vacuum. • Viscoelastic property, structural change and gas evolution were investigated. • Ether linkages in the network structure were mainly decomposed by the irradiation. • The flexural strength of resin was maintained >170 MPa which is 90% of initial value

  15. Effect of cobalt 60 gamma-ray irradiation on the hatching process of chicken eggs

    International Nuclear Information System (INIS)

    An experiment on fertilized chicken eggs was carried out to determine the effects of 60Co irradiation on the embryos, their fatality, and growth impairment or deformity, in particular. The experimental groups, consisting of 10 eggs each, recieved a 60Co irradiation of 50 to 2,000 rads on any one day between day 0 and day 20 of incubation. The larger the irradiation dose, the greater was the number of dead embryos. The fatality was higher in the groups receiving irradiation in the earlier stage (1st week). The resultant death was a chronic one. The irradiation also caused body weight decrease and growth impairment. A decrease in the brain and liver weights was noted, suggesting insufficiency in these organs. Deformity occurred in 4%, most of which involved impairments of skeletal growth, of the bones of the extremities and the bill, in particular. Administration of the SH amino acid, cysteine tended to alleviate the adverse effects of the 60Co irradiation. These results for fertilized chicken eggs suggest the possibility of abortion and the occurrence of deformities in human fetuses if they should be subjected to 60Co irradiation. (author)

  16. Effect of cobalt 60 gamma-ray irradiation on the hatching process of chicken eggs

    Energy Technology Data Exchange (ETDEWEB)

    Ohkuma, Y. (Nihon Univ., Tokyo. School of Medicine)

    1981-10-01

    An experiment on fertilized chicken eggs was carried out to determine the effects of /sup 60/Co irradiation on the embryos, their fatality, and growth impairment or deformity, in particular. The experimental groups, consisting of 10 eggs each, received a /sup 60/Co irradiation of 50 to 2,000 rads on any one day between day 0 and day 20 of incubation. The larger the irradiation dose, the greater was the number of dead embryos. The fatality was higher in the groups receiving irradiation in the earlier stage (1st week). The resultant death was a chronic one. The irradiation also caused body weight decrease and growth impairment. A decrease in the brain and liver weights was noted, suggesting insufficiency in these organs. Deformity occurred in 4%, most of which involved impairments of skeletal growth, of the bones of the extremities and the bill, in particular. Administration of the SH amino acid, cysteine tended to alleviate the adverse effects of the /sup 60/Co irradiation. These results for fertilized chicken eggs suggest the possibility of abortion and the occurrence of deformities in human fetuses if they should be subjected to /sup 60/Co irradiation.

  17. Immune response against antigens irradiated with 60Co gamma-rays

    International Nuclear Information System (INIS)

    In the present work, we investigated the immunological behavior of bothropstoxin-1, a K49 phospholipase from Bothrops jararacussu, and of ovalbumin before and after irradiation with 60Co ?-rays. Isogenic mice were immunized with either native or irradiated proteins. The circulating antibodies were isotyped and titrated by ELISA. Results indicate that irradiated proteins were immunogenic and the antibodies elicited by them were able to recognize the native proteins in ELISA. Data also indicate that the irradiated protein induced higher titers of IgG2a and IgG2b, suggesting that Th1 cells were predominantly involved in the immune response. Structural modifications of the proteins were investigated by SDSPAGE, mass spectrometry and size exclusion chromatography. According to our data, irradiation promoted structural modifications on both proteins, characterized by higher molecular weight forms (aggregates and oligomers). When analyzed by mass spectrometry, the irradiated bothropstoxin appeared in several oxidized forms. These results indicate that irradiation of toxic proteins can promote significant modifications in their structures, but still retain many of the original antigenic and immunological properties of native form. (author)

  18. Effectiveness of gamma-ray chronic irradiation on in vitro mutagenesis in crops

    International Nuclear Information System (INIS)

    Effects of chronic or acute irradiations were compared using in vitro culture on inducing the mutation in model crops. In chrysanthemum, combined method with irradiation and in vitro culture can solve the problem of chimera formation in induced mutants, and provided 10 times greater mutation frequency than usual plant irradiation. The chronic culture method showed the widest color spectrum, whereas, the acute culture indicated a relatively low mutation rate and a very limited flower color spectrum in chrysanthemum. Flower color mutation of the regenerators could be induced more from petals and buds than from leaves. These facts are supposed that the gene loci fully expressed on floral organs may be unstable for mutation by mutagenesis or culture. It may be likely to control a direction of desired mutation on using explants with specific gene loci activated. In sugarcane, the chronic culture method extended quantitative characteristics of regenerated clonal lines toward not only the negative but positive direction. On the other hand, the acute culture method showed lower quantitative mutation as the irradiation dose rose. In chronic irradiation, regenerated mutant lines in sugarcane indicate generally little decrease in chromosome number and wider variations with relatively less damage. In acute irradiation, regenerated mutant lines show remarkable decrease of chromosome numbers in sugarcane mutant lines as the irradiation dose rose. There is close positive correlation rose. There is close positive correlation between chromosome number and biomass of each mutant line. The chromosome number estimation is a proper indicator to monitor damage of adopted irradiation methods. Possible reason why the chronic culture methods indicate higher frequency and wider spectrum on mutation is demonstrated. . Problems solved and prospect of chronic irradiation and in vitro techniques are discussed. (Author)

  19. Investigation of Some Physical Properties of Polypropylene Irradiated by Gamma Rays

    International Nuclear Information System (INIS)

    Pure polypropylene samples were exposed to different doses of gamma radiation up to 100 kGy in presence of nitrogen. Some physical properties were investigated in relation to the radiation dose: melting point, crystallinity, apparent activation energy, tensile strength, elongation. The data show that the crystallinity decreases at low doses. In addition, the melting point is shifted to lower temperature with increasing the irradiation dose. The apparent activation energy increases with increasing irradiation dose. The strain at break decreases with increasing irradiation dose

  20. Behavior of Random Hole Optical Fibers under Gamma Ray Irradiation and Its Potential Use in Radiation Sensing Applications

    Directory of Open Access Journals (Sweden)

    Anbo Wang

    2007-05-01

    Full Text Available Effects of radiation on sensing and data transmission components are of greatinterest in many applications including homeland security, nuclear power generation, andmilitary. A new type of microstructured optical fiber (MOF called the random hole opticalfiber (RHOF has been recently developed. The RHOFs can be made in many differentforms by varying the core size and the size and extent of porosity in the cladding region.The fibers used in this study possessed an outer diameter of 110 μm and a core ofapproximately 20 μm. The fiber structure contains thousands of air holes surrounding thecore with sizes ranging from less than 100 nm to a few μm. We present the first study ofthe behavior of RHOF under gamma irradiation. We also propose, for the first time to ourknowledge, an ionizing radiation sensor system based on scintillation light from ascintillator phosphor embedded within a holey optical fiber structure. The RHOF radiationresponse was compared to normal single mode and multimode commercial fibers(germanium doped core, pure silica cladding and to those of radiation resistant fibers (puresilica core with fluorine doped cladding fibers. The comparison was done by measuringradiation-induced absorption (RIA in all fiber samples at the 1550 nm wavelength window(1545 ± 25 nm. The study was carried out under a high-intensity gamma ray field from a 60Co source (with an exposure rate of 4x104 rad/hr at an Oak Ridge National Laboratory gamma ray irradiation facility. Linear behavior, at dose values less than 106 rad, was observed in all fiber samples except in the pure silica core fluorine doped cladding fiber which showed RIA saturation at 0.01 dB. RHOF samples demonstrated low RIA (0.02 and 0.005 dB compared to standard germanium doped core pure silica cladding (SMF and MMF fibers. Results also showed the possibility of post-fabrication treatment to improve the radiation resistance of the RHOF fibers.

  1. Gamma ray irradiation induced optical band gap variations in chalcogenide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Xia Fang [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, 130 Meilong Road, Box 306, East China University of Science and Technology, Shanghai 200237 (China); ENEA-FIS/ION, Via Anguillarese 301, 00060 S. Maria di Galeria, Rome (Italy); Baccaro, S. [ENEA-FIS/ION, Via Anguillarese 301, 00060 S. Maria di Galeria, Rome (Italy); Zhao Donghui [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, 130 Meilong Road, Box 306, East China University of Science and Technology, Shanghai 200237 (China); Falconieri, M. [ENEA-MAT/NANO, Via Anguillarese 301, 00060 S. Maria di Galeria, Rome (Italy); Chen Guorong [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, 130 Meilong Road, Box 306, East China University of Science and Technology, Shanghai 200237 (China)]. E-mail: grchen@ecust.edu.cn

    2005-07-01

    In the present work {gamma}-irradiation induced optical band gap variations ({delta}E {sub opt}) were investigated on Ge-As-Se and Ge-As-Se-Te chalcogenide glasses. Higher doses of {gamma}-irradiation resulted in decreased E {sub opt}, which was composition dependent. Especially, glasses with stoichiometric compositions showed different {delta}E {sub opt} from nonstoichiometric glasses under the same irradiation conditions. There seemed existence of a threshold E {sub opt} (TE) under the certain dose of irradiation below which {delta}E {sub opt} hardly occurred. Results were interpreted from viewpoint of glass structure, Chemical Bond Approach (CBA) and localized states density theory. Raman analysis supported well these discussions.

  2. Study on the changes in phyicochemical properties of seafood cooking drips by gamma ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jong Il; Kim, Yeon Joo; Kim, Jae Hun; Yoon, Yo Han; Song, Beom Seok; Lee, Ju Woon [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Chun, Byung Soo; Ahn, Dong Hyun [Pukyong National University, Busan (Korea, Republic of); Lee, Ju Yeoun [Chonbuk National University, Jeonju (Korea, Republic of)

    2010-03-15

    Cooking drips which were obtained as by-product after seafood processing in the food industries, still contain lots of proteins, carbohydrates, and other functional materials. But, the seafood cooking drips are easily contaminated because of its rich nutrients, and their color are very dark. This study was conducted to investigate the effect of gamma irradiation on the quality of seafood cooking drips including Hizikia fusiformis, Enteroctopus dofleini, and Thunnus thynnus. The Hunter's color values (L, Brightness) of H. fusiformis, and T.thynnus, were increased with increasing irradiation doses, showing becoming bright. The crude protein content and crude lipid content were increased by gamma irradiation. These results indicated that gamma irradiation increased extraction efficiency of available compounds in cooking drips.

  3. Characterization of Amylopectin irradiated by gamma rays using viscosity and radius gyration technique

    International Nuclear Information System (INIS)

    Food irradiation is one of the most applicable methods that have been used in food industry especially to preserve food. Besides preservation of food, irradiation can also reduce microorganism, inhibit budding and others. However, this method can be misused by some irresponsible organization or person such as irradiate the food over the dose limit value. Therefore, the detection method is important to detect any misused in irradiation method. The objective of this research is to identify any changes in the structure of amylopectin by using radius gyration technique. Besides that, the viscosity of the sample is also determined by using Rheometer. The last objective of this research is to find a relationship between radius gyration and irradiation dose can be determined. Amylopectin and cassava powder were the sample in this research. The samples were irradiated in the gamma-cell at 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, and 10.0 kGy doses. 0 kGy were the controlled sample. The sample were made into gel to analysed using Rheometer and Small Angle X-ray Scattering (SAXS). The viscosity of the sample were analysed by using Rheometer while the radius gyration of the sample were analysed by using SAXS. Hence, the result of this experiment is, the viscosity of amylopectin reduces as the doses increases. But, at 10 kGy, the viscosity of the cassava starch was increased significantly. For the SAXS analysis, it is shows that the graph for amylopectin were fluctuates. While, for casmylopectin were fluctuates. While, for cassava starch the radius gyration increases with doses. Hence, the rheometer technique is suitable to be develop as a detection method in food irradiation. Further research should be done to improve the detection technique in food irradiation. (author)

  4. Gamma ray irradiated goat milk: comparative sensorial analysis with pasteurized goat milk

    International Nuclear Information System (INIS)

    Goat milk consumption has increased in the last years, due to its better digestibility and for constituting a good alternative to cow milk for intolerant people. Brazil has over 10 millions goats, mainly in the Northeast area. Considering that it is very important to increase the shelf-life for this product, this work was done to test the gamma-radiation as a preservation method, evaluating acceptability by sensorial analysis compared with pasteurized milk. The goat milk was bought in the Animal Production Department/ESALQ/USP, Piracicaba, and irradiated with 3,5 kGy in the Food Irradiation Laboratory/CENA/USP, using a cobalt-60 irradiator, type Gammabeam-650, from Nordion, Canada. After irradiation, the samples were maintained under refrigeration at 5 deg C and submitted to sensorial analysis at 1st, 7th and 15th days by 30 untrained tasters. The results indicated, by Tukey test, a significant preference for the pasteurized milk in comparison to the irradiated one, because a hard caprine flavor was developed by the irradiation. (author)

  5. Measurements of potato tubers gamma-ray irradiated in nitrogen gas or carbondioxide gas

    International Nuclear Information System (INIS)

    In this report the respiration of the potato tubers irradiated in nitrogen gas or carbondioxide gas was studied. Potato tubers of common Japanese variety, ''Danshaku'' were used for the examination. Potato tubers of about 2kg were put into each of Triple-Nylon bags and the bags were sealed after replacement of air in bags with nitrogen or carbondioxide gases. More than 16 hours after sealing of bags, the ?-dose (60Co) of 150 Gy or 250 Gy were given to the potato tubers in bags at the dose rate of 104 R/h. After irradiation, all bags were opened in air and amounts of CO2 released by respiration of tubers were measured with Hitachi gas chromatograph analyser Type 023. The amounts of CO2 released from the potato tubers irradiated in open air is shown in Fig. 2. The results show that there is an initial lag period of several hours, followed by a rapid increase in the respiration, after which the CO2 release was gradually decreased. Potato tubers irradiated in nitrogen gas show a similar release of CO2 on time scale to the potato tubers irradiated in open air, but the total amounts of CO2 are approximately half of those of the potato tubers irradiated in open air (Figs. 3 and 4). (J.P.N.)

  6. Roentgenographic observation on development and formation of the teeth irradiated by 60Co-gamma ray

    International Nuclear Information System (INIS)

    On a 4-year-old boy who received radiotherapy for malignant tumor in his right mandibula, development of the teeth of 3rd to the 7th in the upper left side and the 3rd to the 7th in the upper right side was observed for 8 years. In the teeth of the 3rd to the 7th in the upper left side which were in irradiated field, and the teeth, except for the teeth of the 3rd to the 6th in the upper left side which had already completed development before irradiation, showed remarkable abnormalities in the shape of the crown such as atrophy, dwarfishness, and flatness. Also the teeth of the 3rd to the 7th of the upper right side which were not in irradiated field, teeth except for the those of the 3rd to the 6th in the upper right side showed slight abnormality in the shape of the crown and root. In irradiated teeth of the 3rd to the 7th in the upper left side, development and formation of teeth were remarkably interfered so that the teeth were almost rootless. In non-irradiated teeth of the 3rd to the 7th in the upper right side atrophy, dwarfishness, and hypoplasia in width and in diameter too. In irradiated teeth of the 3rd to the 7th in the upper left side, calcification was highly advanced in comparison with that in non-irradiated teeth of the 3rd to the 7th in the upper right side or that in normal upper right side. Also in non-irradiated teeth of the 3rd in the 7th in the upper right side, calcification was slightly advanced compared with that in normal teeth. In irradiatedd with that in normal teeth. In irradiated teeth of the 3rd to the 7th in the upper left side, the eruption of the teeth was remarkably facilitated. The irradiated tooth of the 6th in the upper left side fell out early and the other teeth were seen in planted condition on the mandibula. This seemed to be due to the foreign body eliminating mechanism. (Ueda, J.)

  7. Structure alteration and immunological properties of 60Co gamma rays irradiated bothropstoxin-I

    International Nuclear Information System (INIS)

    About 20000 ophidic accidents are registered every year in Brazil. Serum therapy with equine antisera is the only efficient treatment. The venoms employed for immunization are fairly toxic and some venoms present low immunogenicity. Thus, the obtention of modified antigens with lower toxicity and preserved or improved immunogenicity would be useful. These toxins, when submitted to gamma radiation, in aqueous solution, present structural modifications. This occurs due to reactions with the radiolysis products of water. Some scavenger substances, such as NaNO3 and t-butanol, remove selectively the water radiolysis products. Ionizing radiation has proven to be a powerful tool to attenuate snake venoms toxicity without affecting and even increasing their immunogenic properties. However, the immune mechanisms involved in recognition, processing and presentation of irradiated antigens are yet unclear. In the present work, we investigated the immunological behavior of bothropstoxin-I (Bthx-1), before and after irradiation, in the presence of selective scavengers. Isogenic mice were immunized with either the native or the irradiated toxin, either with or without scavengers. After three immunizations, serum samples were collected and the antibody titers and isotypes were determined by Enzyme Linked Immuno Sorbent Assay. The antigenic characterization of native and irradiated bothropstoxin-I was performed by Western blot. The detection of expression of murine cytokin detection of expression of murine cytokines (IFN-? and IL-10) was analyzed by RT-PCR (Reverse Transcriptase-Polymerase Chain Reaction). According to our data, irradiation process has promoted structural modifications in the toxin, characterized by higher molecular weight forms of the protein (aggregates and oligomers). Our data also indicate that irradiated toxins, alone or in the presence of NaNO3, an aqueous electron scavenger, were immunogenic and the antibodies elicited by them were able to recognize the native toxin. On the other hand, when the toxin was irradiated in presence of t-butanol, a discrete reduction in antibodies levels was observed, suggesting a role of hydroxyl radicals in the modulation of immune response. Irradiated bothropstoxin-1 elicited antibodies responsive to both toxins forms, as demonstrated by Western blot. The cytokines profiles indicated that IFN-? mRNA presence appeared to be higher for mice immunized with irradiated toxin, while IL-10 mRNA presence was predominant with the antigen in its native form. These results indicate that irradiation of proteins leads to significant structural modifications, and also to a modulation of the immunological response. (author)

  8. Influence of Gamma-Ray Irradiation on Absorption and Fluorescent Spectra of Nd:YAG and Yb:YAG Laser Crystals

    International Nuclear Information System (INIS)

    We investigate the influence of gamma-ray irradiation on the absorption and fluorescent spectra of Nd3+:Y3A15O12 (Nd:YAG) and Yb3+:Y3A15O12 (Yb:YAG) crystals grown by the Czochralski method. Two additional absorption (AA) bands induced by gamma-ray irradiation appear at 255nm and 340 nm. The former is contributed due to Fe3+ impurity, the latter is due to Fe2+ ions and F-type colour centres. The intensity of the excitation and emission spectra as well as the fluorescent lifetime of Nd:YAG crystal decrease after the irradiation of 100Mrad gamma-ray In contrast, the same dose irradiation does not impair the fluorescent properties of Yb:YAG crystal. These results indicate that Yb:YAG crystal possesses the advantage over Nd:YAG crystal that has better reliability for applications in harsh radiant environment. (fundamental areas of phenomenology (including applications))

  9. Thermal characterization of the HDPE/LDPE blend (10/90) irradiated using gamma-rays

    Energy Technology Data Exchange (ETDEWEB)

    Puig, C.C., E-mail: cpuig@usb.v [Universidad Simon Bolivar, Departamento de Ciencia de los Materiales, Grupo de Polimeros USB, Apdo. 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); Albano, C., E-mail: calbano@ivic.v [Instituto Venezolano de Investigaciones Cientificas (IVIC), Centro de Quimica, Laboratorio de Polimeros, Apdo. 21827, Caracas 1020-A (Venezuela, Bolivarian Republic of); Universidad Central de Venezuela, Facultad de Ingenieria, Escuela de Ingenieria Quimica, Laboratorio de Polimeros, Caracas (Venezuela, Bolivarian Republic of); Laredo, E. [Universidad Simon Bolivar, Departamento de Fisica, Grupo de Fisica de Materiales Amorfos y Cristalinos, Apdo. 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); Quero, E. [Universidad Simon Bolivar, Departamento de Ciencia de los Materiales, Grupo de Polimeros USB, Apdo. 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); Karam, A. [Instituto Venezolano de Investigaciones Cientificas (IVIC), Centro de Quimica, Laboratorio de Polimeros, Apdo. 21827, Caracas 1020-A (Venezuela, Bolivarian Republic of)

    2010-05-01

    Gamma irradiation effect over the properties of slow cooled and fast cooled HDPE/LDPE 10/90 blend was studied. The blend and the neat polyethylenes were irradiated at room temperature in the presence of air using the following doses (4.8 kGy/h): 0, 50, 150, 400 and 1000 kGy. Differential scanning calorimetry (DSC) experiments were carried out using the following heating rates: 5, 10 and 20 deg. C/min. DSC results for the slow and fast cooled blend showed traces with three melting peaks and with increasing irradiation dose two melting peaks were obtained, i.e. the high melting peak shifts toward lower temperatures to merge with the intermediate melting peak into one endotherm. No changes in crystal structure by X-ray diffraction were found as a result of samples irradiation. Radiation crosslinking prevents crystal rearrangements during heating in the DSC. Gel content and melt flow index (MFI) measurements showed that radiation induced a high degree of crosslinking for all samples; gel content values were above 50% and a drop of more than 90% in the MFI was found. Irradiation of slow cooled samples resulted in larger values of gel content and lower MFI values than for fast cooled samples, mainly because of the higher degree of crosslinking for the former.

  10. A comparative study on experimental and theoretical ESR spectra of lactic acid polymers irradiated by gamma rays

    International Nuclear Information System (INIS)

    Homo polymers of L-Lactic acid (LLA) and D,L-Lactic acid (DLLA), being biocompatible and absorbable in body iluids have recently found wide applications in the preparation of surgical sutures, controlled drug delivery systems, burn wound coverings etc. For sometime these polymers have also been prepared in the form of plates and screws for mandibular fracture fixation, tissue implants. Their chemical sensitivities against relatively high temperatures and hydrolysis with water make them unsuitable for conventional sterilization techniques like hot water vapor and ethylene oxide. Sterilization of the devices made of these polymers is therefore possible by gamma ray irradiation. This has initiated a number of research works in order to better understand the effects of ionizing radiation on this polymer. The aim of this study is to determine the possible radical types, their location on macromolecular structure and the reasons for peak shifts in the experimental and theoretical ESR spectra. Polymer samples were irradiated in air and in vacuum (10?? torr) to 25 kGy sterilization dose at the dose rate 0.59 kGy/h and at room temperature by 60Co ?-irradiator. Despite being chemically the same radical type, some differences were observed in the splitting of peaks of PLLA and PDLLA samples. These differences were determined and compared by means of fitting studies. Firstly, PLLA was characterized and its g and hyperfine splitting values were found as 2.0032±0.0002 and 20.37±0.2. In the characterization study of PDLLA, it was found that one of the nearest two radicals was on the upper and the other one was on the lower plane of PDLLA chain. (author)

  11. Effect of the irradiation on Salmonella enteretidis var. typhimurium with gamma rays from 60Co

    International Nuclear Information System (INIS)

    The use of ionizinf radiation to the destruction of microrganisms responsible for food deterioration, and productive of feeding toxinfections constitute their usefulness for actually peaceful goals of nuclear energy. The feeding toxinfections are, among us, produced in their most part by Salmonella enteritidis var. typhimurim. One hundred nineteen samples of milk containing about 150.000 bacteria per ml, by means doses ranging from 100 to 1.100 gy, two samples of surviving bacteria were again irradiated by doses up to 2.5000 Gy. The bacteria not previously irradiated were throughly killed by means of doses of 1.100 Gy. Salmonella enteritidis var. typhimurium was inactivated by means of 1.200 and 1.900 Gy doses. It was concluded that 60-Cobalt gamma radiation minimal lethal dose to Salmonella enteritidis var. typhimurium is 1.200 Gy; the re-irradiation to the survivors prompts the forthcoming of more resistant germs. (author)

  12. Characterization of injected linear low density polyethylene (LLDPE) irradiated by gamma-ray

    International Nuclear Information System (INIS)

    The aim of this paper is to investigate of gamma irradiation effects on linear low density polyethylene (LLDPE) injected. Polymers processed by gamma radiation have new physical-chemical and mechanical properties. The ionizing radiation promotes chain scission and creates free radicals which can recombine, providing their annihilation, for crosslinking or branching. The polymer was irradiated with a source of 60Co at doses of 5, 10, 20, 50 or 100 kGy at about 5 kGy s-1 rate, at room temperature. The changes in molecular structure of LLDPE were evaluated using melt flow index, gel fraction, differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FT-IR) and thermogravimetry analysis (TG). The results showed that the properties depend on dose irradiation. (author)

  13. Development and characterization of biodegradable polymer blends - PHBV/PCL irradiated with gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Rosario, F. [Faculdade de Tecnologia da Zona Leste (FATEC-ZL), Sao Paulo, SP (Brazil). Centro Paulo Souza; Casarin, S.A.; Agnelli, J.A.M. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais; Souza Junior, O.F. de [Universidade de Sao Paulo (IFSC/USP), Sao Carlos, SP (Brazil). Inst. de Fisica

    2010-07-01

    This paper presents the results of a study that aimed to develop PHBV biodegradable polymer blends, in a major concentration with PCL, irradiate the pure polymers and blends in two doses of gamma radiation and to analyze the changes in chemical and mechanical properties. The blends used in this study were from natural biodegradable copolymer poly (hydroxybutyrate-valerate) (PHBV) and synthetic biodegradable polymer poly (caprolactone) (PCL 2201) with low molar mass (2,000 g/mol). Several samples were prepared in a co-rotating twin-screw extruder and afterwards, the tensile specimens were injected for the irradiation treatment with 50 kGy to 100 kGy doses and for the mechanical tests. The characterization of the samples before and after the irradiation treatments was performed through scanning electron microscopy (SEM), dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and mechanical tensile tests. (author)

  14. Development and characterization of biodegradable polymer blends - PHBV/PCL irradiated with gamma rays

    International Nuclear Information System (INIS)

    This paper presents the results of a study that aimed to develop PHBV biodegradable polymer blends, in a major concentration with PCL, irradiate the pure polymers and blends in two doses of gamma radiation and to analyze the changes in chemical and mechanical properties. The blends used in this study were from natural biodegradable copolymer poly (hydroxybutyrate-valerate) (PHBV) and synthetic biodegradable polymer poly (caprolactone) (PCL 2201) with low molar mass (2,000 g/mol). Several samples were prepared in a co-rotating twin-screw extruder and afterwards, the tensile specimens were injected for the irradiation treatment with 50 kGy to 100 kGy doses and for the mechanical tests. The characterization of the samples before and after the irradiation treatments was performed through scanning electron microscopy (SEM), dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and mechanical tensile tests. (author)

  15. Growth evaluation of avocado selections irradiated with gamma rays Co 60

    International Nuclear Information System (INIS)

    The vegetative growth of two years old avocado selections treated with 2 krads of gamma irradiation compared with not irradiated trees (control) was evaluated determining tree height, trunk diameter, shoots length, inter nodes number and growth habit, finding that the irradiated selections Colinmex, 175 PLS and 39 PMe have modified their growth habits towards more horizontal tendency, minor shoots length and more inter nodes. Also in this article is presented an evaluation of the scion development of 10 avocado selections treated with 0,1,3,5 and 7 krad, finding variation in the sensibility of the materials after eight months grafted, Colin V-101, 131 PLS and 175 PLS exhibited only 12 % survival meanwhile Colin V-33 and Colinmex had 70 % survival, but only in the 1 krad dosage, because at higher doses the graft wood died. (Author)

  16. Physico chemical and microbiological changes in nopal (Opuntia spp.) irradiated with gamma rays of cobalt 60

    International Nuclear Information System (INIS)

    The objective of this work is to study the physico-chemical and microbiological changes which take place in the nopal (Opuntia spp.) after they have been irradiated and stored at environment and refrigeration temperatures in order to determine the level of irradiation dose more adequate for getting them an increase in the storage life, as well as to determine the physico-chemical changes attributed to the irradiation doses used, comparing the obtained results with those ones of non-irradiated nopal samples, which are considered as control samples. The radiation source used was a GAMMABEAM-651 PT, property of the Nuclear Sciences Institute of UNAM. The nopals studied are of the variety (Milpa Alta, Opuntia ficus) which were cut and packed in polyethylene bags with and without nitrogen. In order to find the adequate dose level it was used a lot of 200 samples which were treated in sets of 10. They were irradiated in doses of 0.5 to 10 kGy at a dose reason of 3.7 kGy/h. The adequate doses for getting an increase in the storage life, where there was not darkness were of 1.5 and 2.0 kGy, allowed doses in the NOM-033-SSA1-1993, it was not found any change in acceptability by flavour, but so in the titled activity values and sugars. The lowest loss of weight was found in the 1.5 kGy dose without nitrogen and the highest in the 2.0 kGy with nitrogen dose. Likewise was determined that with the irradiation treatment in the recommended doses it is diminished the microorganisms growth, obtaining an improvement in the general appearance of the nopals during their storage period. (Author)

  17. Effect of gamma-ray irradiation on raw and chemically treated cotton cellulose

    International Nuclear Information System (INIS)

    The effects of gamma-irradiation on native as well as chemically modified cotton cellulose are reviewed briefly and critically. For the present purpose, the results available have been grouped into: (i) radiationneffects on native and mercerized cotton, (ii) modification of radiation effects in cottons chemically substituted with aromatic esters and unsaturated ethers, (iii) radio-protective or sensitizing action of common reagents (acids, alcohols and amines) when cotton is irradiated in their presence, and (iv) possible application of irradiation techniques in the cotton finishing field. The radiation effects have been assessed through measurements of tensile properties (load and elongation at break) as well as chemical properties (degree of polymerisa. tion, oxidation, nature of oxycelluloses). Further, the nature and behaviour of the radiation induced free radicals have been studied using ESR techniques and the ultimate effects examined in the light of the information so gathered. The results show that the effects of irradiation of cotton cellulose are depolymerization and oxidation at the molecular level, and that these can be understood in terms of the free radicals formed mainly by dehydrogenation and chain cleavage. Aromatic substitutions impart protection to cellulose from degradation, perhaps through energy transfer mechanisms. Etherification also offers protection, although the protective effects are not reflected in all the properties. Both protective and n all the properties. Both protective and sensitizing action have been noticed when irradiation is done in the presence of chemicals, depending on the nature of the reagent. The relevance of these results in radiation sterilization of celluloses, and in imparting desirable, textile properties to cotton materials through post-irradiation reactions such as grafting, cross-linking etc. are finally discussed. (author)

  18. Myeloid leukemia in male RFM mice following irradiation with fission spectrum neutrons or gamma rays

    International Nuclear Information System (INIS)

    The induction of myeloid leukemia following fission neutron irradiation was examined over the 0-80 rad dose range. Over this dose range the dose response could be described by the linear regression equation: y = 0.94 + 0.18X. A comparison of these data with data obtained following gamma irradiation from this study and a previous study indicated that the relative biological effectiveness for myeloid leukemia induction was 2.8. These results appear to be compatible with those reported by other investigators

  19. Induction of skin papillomas in the rabbit, Oryctologus cuniculus, by bites of a blood-sucking insect, Cimex lectularius, irradiated by gamma rays

    International Nuclear Information System (INIS)

    Bed bugs, Cimex lectularius, irradiated with gamma rays were allowed to suck blood from shaved areas of the skin of rabbits, Oryctolagus cuniculus, 2 times/week for 5 months and then once weekly for another 5 months. This significantly induced the formation of skin papillomas and sweat gland hyperplasia in five out of nine experimental animals. It is speculated that the saliva of the irradiated bugs was activated by gamma rays and was responsible for the induction of skin papillomas. Because bed bugs play a significant role in the transmission of virus, it is also speculated that there is a virus in the saliva of bugs; this virus may be activated by gamma radiation and causes the development of papillomas in the skin

  20. Selection of mutants resistant to black spot disease by chronic irradiation of gamma-rays in Japanese pear 'Osanijisseiki'

    International Nuclear Information System (INIS)

    'Osanijisseiki', a self-compatible, spontaneous bud sport of the Japanese pear 'Nijisseiki' is an excellent cultivar with a smooth skin. However, this cultivar is susceptible to Japanese pear black spot disease caused by Alternaria alternata Japanese pear pathotype. To obtain resistant mutants from 'Osanijisseiki', nursery plants of 'Osanijisseiki' have been irradiated chronically with gamma-rays in the Gamma Field of the Institute of Radiation Breeding, NAR, MAFF, since 1986. Screening tests using AK toxin, a host-specific toxin produced by A. alternata Japanese pear pathotype, were performed form 1988 to 1993. Four branches of young trees planted at a distance of 40 m from the 60Co source were selected as being resistant mutants in 1991 (IRB 502-13T and IRB 502-14T) and 1993 (IRB 502-17T and IRB 502-18T). Sensitivity of the four resistant mutants to AK-toxin and susceptibility to the pathogen were compared with other of susceptible and resistant cultivars. The results showed that these four mutants possessed intermediate resistance. Furthermore, a mutant, IRB 502-13T, had the same characteristics as the original 'Osanijisseiki', except for the difference in toxin sensitivity. The characteristics of the other mutants, IRB 502 14-T, IRB 502-17T, and IRB 502-18T, care being examined. (author)

  1. Gamma ray irradiation induced degradation in ultra-thin silica layers

    International Nuclear Information System (INIS)

    In this paper, the influence of gamma irradiation on the electrical properties of Metal-Oxide-Semiconductor (MOS) with an ultra-thin silica layer N2O nitrided or not is investigated. Mainly electron trapping, defects generation and breakdown during electrical stress are studied. (author)

  2. Work hardening characteristics of gamma-ray irradiated Al-5356 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Saad, G. [Physics Department, Faculty of Education, Ain Shams University, Cairo (Egypt); Fayek, S.A. [Physics Department, National Center for Radiation Research and Technology, Nasr City, Cairo (Egypt); Fawzy, A. [Physics Department, Faculty of Education, Ain Shams University, Cairo (Egypt); Soliman, H.N., E-mail: dr_hany.nazmy@yahoo.com [Physics Department, Faculty of Education, Ain Shams University, Cairo (Egypt); Nassr, E. [Physics Department, Faculty of Education, Ain Shams University, Cairo (Egypt)

    2014-06-01

    Effects of ?-irradiation and deformation temperatures on the hardening behavior of Al-5356 alloy have been investigated by means of stress–strain measurements. Wire samples irradiated with different doses (ranging from 500 to 2000 kGy) were strained at different deformation temperatures T{sub w} (ranging from 303 to 523 K) and a constant strain rate of 1.5×10{sup ?3} s{sup ?1}. The effect of ?-irradiation on the work-hardening parameters (WHP): yield stress ?{sub y}, fracture stress ?{sub f}, total strain ?{sub T} and work-hardening coefficient ?{sub p} of the given alloy was studied at the applied deformation temperature range. The obtained results showed that ?-irradiation exhibited an increase in the WHP of the given alloy while the increase in its deformation temperature showed a reverse effect. The mean activation energy of the deformation process was calculated using an Arrhenius-type relation, and was found to be ?80 kJ/mole, which is close to that of grain boundary diffusion in aluminum alloys.

  3. Work hardening characteristics of gamma-ray irradiated Al-5356 alloy

    International Nuclear Information System (INIS)

    Effects of ?-irradiation and deformation temperatures on the hardening behavior of Al-5356 alloy have been investigated by means of stress–strain measurements. Wire samples irradiated with different doses (ranging from 500 to 2000 kGy) were strained at different deformation temperatures Tw (ranging from 303 to 523 K) and a constant strain rate of 1.5×10?3 s?1. The effect of ?-irradiation on the work-hardening parameters (WHP): yield stress ?y, fracture stress ?f, total strain ?T and work-hardening coefficient ?p of the given alloy was studied at the applied deformation temperature range. The obtained results showed that ?-irradiation exhibited an increase in the WHP of the given alloy while the increase in its deformation temperature showed a reverse effect. The mean activation energy of the deformation process was calculated using an Arrhenius-type relation, and was found to be ?80 kJ/mole, which is close to that of grain boundary diffusion in aluminum alloys

  4. Annealing effect on critical temperature and resistivity of (Bi, Pb) 2Sr 2Ca 2Cu 3O y superconductor irradiated by Co-60 gamma-rays

    Science.gov (United States)

    Makarenko, L. F.; Gurinovich, V. A.; Kononyuk, I. F.

    1992-12-01

    It was found that annealing at 150-200°C results in increase of resistivity and drop of critical temperature of superconducting (Bi, Pb) 2Sr 2Ca 2Cu 3O y ceramics irradiated by Co-60 gamma-rays up to doses of 2 × 10 9R. These parameters recovered afterwards upon annealing at temperatures 300-350°C. The correlation between the recovery temperatures of irradiated and pre-heated at 100°C samples was established. It is suggested that the annealing effects are connected to changes in Bi?O twin layers properties due to gamma-irradiation enhancement of gas exchange processes.

  5. Annealing effect on critical temperature and resistivity of (Bi, Pb)2Sr2Ca2Cu3Oy superconductor irradiated by Co-60 gamma rays

    International Nuclear Information System (INIS)

    It was found that annealing at 150-200oC results in increase of resistivity and drop of critical temperature of superconducting (Bi, Pb)2Sr2Ca2Cu3Oy ceramics irradiated by Co-60 gamma-rays up to doses of 2 x 109R. These parameters recovered afterwards upon annealing at temperatures 300-350oC. The correlation between the recovery temperatures of irradiated and pre-heated at 100oC samples was established. It is suggested that the annealing effects are connected to changes in Bi-O twin layer properties due to gamma-irradiation enhancement of gas exchange processes. (author)

  6. Changes in melatonin in epiphysis after whole-body irradiation of rats with gamma rays

    International Nuclear Information System (INIS)

    Male Wistar rats were exposed to a whole-body gamma dose of 14.4 or 9.6 Gy in darkness. Other groups were exposed to fractionated irradiation with 2.4 Gy twice a week up to 9.6 and 14.4 Gy. At 30 and 60 min after acute lethal irradiation, a decrease in the melatonin (Mel) concentration in the epiphysis was observed; the activity of N-acetyltransferase (NAT) did not differ from that in the control group. Later, signs of increased synthesis of Mel were observed. NAT activity and Mel concentration in the serum increased on day 3 following exposure to 14.4 Gy. Concentration of Mel in epiphysis and serum increased 5 days after exposure to 9.6 Gy. Fractionated irradiation up to 9.6 Gy brought about a decrease in NAT activity 6 h after exposure, without changes in Mel in epiphysis. In rats with an accumulated dose of 14.4 Gy, NAT activity and Mel concentration in epiphysis (serum) decreased 6 h and 3 days, respectively, after exposure, and monoaminooxidase (MAO) increased appreciably on day 3. On day 5, the enzyme activities and Mel concentrations did not differ from those in the control group. Fractionated irradiation up to 14.4 Gy brought about temporary decrease in the synthesis of Mel in epiphysis, which may be due to preferential oxidative deamination of serotonin as compared to its N-acetylation leading to the synthesis of melatonin. The temporary decrease in the Mel concentration in epiphysis in 60 min after single-dose exposure to 14.4 or 9.6 Gy may be a result of similar metabolic changes. The increased synthesis of Mel in epiphysis at a later stage following acute lethal exposure is seen as an adaptive effort of the organism to produce a sufficient amount of hormone with an antioxidative, antistress and immunomodulative effect

  7. Inclusion polymerization of vinyl chloride monomer in deoxycholic acid host via {gamma}-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chirachanchai, S.; Kumkrong, A. [The Petroleum and Petrochemical College, Chulalongkorn University, Bangkok (Thailand); Ishida, Hatsuo [Department of Macromolecular Science, Case Western Reserve University, Cleveland, OH (United States)

    2000-03-01

    Inclusion polymerization of vinyl chloride monomer (VCM) was studied in the system of 3{alpha}, 12{alpha} -dihydroxy-5{beta}-cholan-24-oic acid (deoxycholic acid, DCA). DCA-VCM inclusion compound system was originally prepared by guest intercalation technique in DCA guest free crystal. The inclusion polymerization of DCA-VCM by {gamma}-irradiation at total dose 2 Mrad, gives a syndiotactic rich polyvinyl chloride (PVC) as can be confirmed by FT-IR and FT-NMR. (author)

  8. Quality assessment of coffee beans with ESR and gamma-ray irradiation

    International Nuclear Information System (INIS)

    Peroxy radical formation in raw coffee beans of different qualities and origins from all over the world has been studied with electron spin resonance (ESR) analysis. The ?-ray equivalent absorbed dose (ED) which creates the same concentration of radicals is obtained by the additive ?-ray irradiation of the coffee beans. The ED and the cup quality is somewhat inversely related suggesting that the peroxidation of the unsaturated fatty acid is somewhat indicative of the degree of the aromatic decomposition and rancidity. (author)

  9. Functionalization and magnetization of carbon nanotubes using Co-60 gamma-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.Y.; Fu, M.J.; Tsai, C.Y. [Division of Isotope Application, Institute of Nuclear Energy Research, Atomic Energy Council, P.O. BOX 3-27 Longtan, Taoyuan County 32546, Taiwan (R.O.C.) (China); Lin, F.H. [Institute of Biomedical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (R.O.C.) (China); Chen, K.Y., E-mail: chenky@iner.gov.tw [Division of Isotope Application, Institute of Nuclear Energy Research, Atomic Energy Council, P.O. BOX 3-27 Longtan, Taoyuan County 32546, Taiwan (R.O.C.) (China)

    2014-10-01

    Functionalized magnetic carbon nanotubes (CNTs) can be used in the biological and biomedical fields as biosensors, drug delivery systems, etc., which makes research into processes for manufacturing modified CNTs quite important. In this paper, Co-60 gamma irradiation is shown to be an effective tool for fabricating functionalized and magnetized CNTs. After the Co-60 gamma irradiation, the presence of carboxylic functional groups on the CNT walls was confirmed by their Fourier transform infrared spectra, and the presence of Fe{sub 3}O{sub 4} was verified by the X-ray diffraction patterns. The functionalized and magnetized CNTs produced using Co-60 gamma irradiation have excellent dispersion properties. The techniques for functionalizing and magnetizing CNTs are introduced in this paper, and applications of the modified CNTs will be reported after more data are gathered. - Highlights: Dispersion ability of carbon nanotubes (CNTs) was improved by functionalization. CNTs were easily manipulated by precipitation of magnetic nanoparticles. Our product can be used as versatile biosensor substrate for biomarker screening.

  10. Functionalization and magnetization of carbon nanotubes using Co-60 gamma-ray irradiation

    International Nuclear Information System (INIS)

    Functionalized magnetic carbon nanotubes (CNTs) can be used in the biological and biomedical fields as biosensors, drug delivery systems, etc., which makes research into processes for manufacturing modified CNTs quite important. In this paper, Co-60 gamma irradiation is shown to be an effective tool for fabricating functionalized and magnetized CNTs. After the Co-60 gamma irradiation, the presence of carboxylic functional groups on the CNT walls was confirmed by their Fourier transform infrared spectra, and the presence of Fe3O4 was verified by the X-ray diffraction patterns. The functionalized and magnetized CNTs produced using Co-60 gamma irradiation have excellent dispersion properties. The techniques for functionalizing and magnetizing CNTs are introduced in this paper, and applications of the modified CNTs will be reported after more data are gathered. - Highlights: Dispersion ability of carbon nanotubes (CNTs) was improved by functionalization. CNTs were easily manipulated by precipitation of magnetic nanoparticles. Our product can be used as versatile biosensor substrate for biomarker screening

  11. Simulation and experimental verification of prompt gamma-ray emissions during proton irradiation

    Science.gov (United States)

    Schumann, A.; Petzoldt, J.; Dendooven, P.; Enghardt, W.; Golnik, C.; Hueso-González, F.; Kormoll, T.; Pausch, G.; Roemer, K.; Fiedler, F.

    2015-05-01

    Irradiation with protons and light ions offers new possibilities for tumor therapy but has a strong need for novel imaging modalities for treatment verification. The development of new detector systems, which can provide an in vivo range assessment or dosimetry, requires an accurate knowledge of the secondary radiation field and reliable Monte Carlo simulations. This paper presents multiple measurements to characterize the prompt ?-ray emissions during proton irradiation and benchmarks the latest Geant4 code against the experimental findings. Within the scope of this work, the total photon yield for different target materials, the energy spectra as well as the ?-ray depth profile were assessed. Experiments were performed at the superconducting AGOR cyclotron at KVI-CART, University of Groningen. Properties of the ?-ray emissions were experimentally determined. The prompt ?-ray emissions were measured utilizing a conventional HPGe detector system (Clover) and quantitatively compared to simulations. With the selected physics list QGSP_BIC_HP, Geant4 strongly overestimates the photon yield in most cases, sometimes up to 50%. The shape of the spectrum and qualitative occurrence of discrete ? lines is reproduced accurately. A sliced phantom was designed to determine the depth profile of the photons. The position of the distal fall-off in the simulations agrees with the measurements, albeit the peak height is also overestimated. Hence, Geant4 simulations of prompt ?-ray emissions from irradiation with protons are currently far less reliable as compared to simulations of the electromagnetic processes. Deviations from experimental findings were observed and quantified. Although there has been a constant improvement of Geant4 in the hadronic sector, there is still a gap to close.

  12. Simulation and experimental verification of prompt gamma-ray emissions during proton irradiation.

    Science.gov (United States)

    Schumann, A; Petzoldt, J; Dendooven, P; Enghardt, W; Golnik, C; Hueso-González, F; Kormoll, T; Pausch, G; Roemer, K; Fiedler, F

    2015-05-21

    Irradiation with protons and light ions offers new possibilities for tumor therapy but has a strong need for novel imaging modalities for treatment verification. The development of new detector systems, which can provide an in vivo range assessment or dosimetry, requires an accurate knowledge of the secondary radiation field and reliable Monte Carlo simulations. This paper presents multiple measurements to characterize the prompt ?-ray emissions during proton irradiation and benchmarks the latest Geant4 code against the experimental findings. Within the scope of this work, the total photon yield for different target materials, the energy spectra as well as the ?-ray depth profile were assessed. Experiments were performed at the superconducting AGOR cyclotron at KVI-CART, University of Groningen. Properties of the ?-ray emissions were experimentally determined. The prompt ?-ray emissions were measured utilizing a conventional HPGe detector system (Clover) and quantitatively compared to simulations. With the selected physics list QGSP_BIC_HP, Geant4 strongly overestimates the photon yield in most cases, sometimes up to 50%. The shape of the spectrum and qualitative occurrence of discrete ? lines is reproduced accurately. A sliced phantom was designed to determine the depth profile of the photons. The position of the distal fall-off in the simulations agrees with the measurements, albeit the peak height is also overestimated. Hence, Geant4 simulations of prompt ?-ray emissions from irradiation with protons are currently far less reliable as compared to simulations of the electromagnetic processes. Deviations from experimental findings were observed and quantified. Although there has been a constant improvement of Geant4 in the hadronic sector, there is still a gap to close. PMID:25955576

  13. Repair of skin damage during fractionated irradiation with gamma rays and low-LET carbon ions

    International Nuclear Information System (INIS)

    In clinical use of carbon-ion beams, a deep-seated tumor is irradiated with a Spread-Out Bragg peak (SOBP) with a high-linear energy transfer (LET) feature, whereas surface skin is irradiated with an entrance plateau, the LET of which is lower than that of the peak. The repair kinetics of murine skin damage caused by an entrance plateau of carbon ions was compared with that caused by photons using a scheme of daily fractionated doses followed by a top-up dose. Right hind legs received local irradiations with either 20 keV/?m carbon ions or ? rays. The skin reaction of the irradiated legs was scored every other day up to Day 35 using a scoring scale that consisted of 10 steps, ranging from 0.5 to 5.0. An isoeffect dose to produce a skin reaction score of 3.0 was used to obtain a total dose and a top-up dose for each fractionation. Dependence on a preceding dose and on the time interval of a top-up dose was examined using ? rays. For fractionated ? rays, the total dose linearly increased while the top-up dose linearly decreased with an increase in the number of fractions. The magnitude of damage repair depended on the size of dose per fraction, and was larger for 5.2 Gy than 12.5 Gy. The total dose of carbon ions with 5.2 Gy per fraction did not change till 2 fractions, but abruptly increased at the 3rd fraction. Factors such as rapid repopulation, induced repair and cell cycle synchronization are possible explanations for the abrupt increase. As an abrupt increase/brupt increase. As an abrupt increase/decrease of normal tissue damage could be caused by changing the number of fractions in carbon-ion radiotherapy, we conclude that, unlike photon therapy, skin damage should be carefully studied when the number of fractions is changed in new clinical trials. (author)

  14. Radio protective effects of calcium channel blockers (Deltiazem) on survival of Saccharomyces cerevisiae cells irradiated with different doses of gamma rays

    International Nuclear Information System (INIS)

    Investigations of radioprotective effects of Deltiazem (as one of the commonly used calcium channel blockers, which is used in the treatment of acute and chronic angina and spasmo angina, in addition to the treatment of different types of essential hypertension) has been carried on Saccharomyces Cerevisiae cells. Cells cultures of the most famous yeast Saccharomyces Cerevisiae (bakers yeast) were irradiated with different doses of gamma rays. Results revealed that the necessary dose of gamma rays that leads to 10% of survived cellular population (D10 value) was about 256 Gy. This irradiation dose was used then in all irradiation experiments on culture of S. Cerevisiae cells in which different concentrations of Deltiazem (55, 110, 165 mg/Kg medium) were added before and after irradiation in order to study the radio protective effect of Deltiazem. Results showed that Deltiazem enhances survival percentage of irradiated S. Cerevisiae cultures in a concentration dependent manner. This study confirmed our previous works, which had demonstrated that Deltiazem protects lethally and supralethally irradiated rats, and enhances survival of pre-irradiated Deltiazem treated animals.(author)

  15. Effects of hydrazine addition and N2 atmosphere on the corrosion of reactor vessel steels in diluted seawater under gamma-rays irradiation

    International Nuclear Information System (INIS)

    Seawater was injected into the reactor cores in the Fukushima Daiichi Nuclear Power Station. Corrosion of primary containment vessel (PCV) steel and reactor pressure vessel (RPV) steel is considered to progress until the molten fuel debris is removed. To evaluate durability of the PCV and RPV steels, corrosion tests were conducted in diluted seawater at 50°C under gamma-rays irradiation of dose rates of 4.4 and 0.2 kGy/h. To evaluate the effect of hydrazine (N2H4) as an oxygen scavenger under gamma-rays irradiation, 10 and 100 mg/L N2H4 were added to the diluted seawater. Without addition of N2H4, weight loss in the PCV and RPV steels irradiated with the 0.2 kGy/h dose rate was comparable with those without irradiation and weight loss in the vessel steels irradiated with the 4.4 kGy/h dose rate was higher than those without irradiation. Under irradiation, weight loss in the PCV and RPV steels in diluted seawater containing N2H4 was comparable with that in diluted seawater without N2H4. When gas phase in the flask was replaced with N2, weight loss in the PCV and RPV steels, and O2 and H2O2 concentrations in the diluted seawater decreased. (author)

  16. Gamma-ray irradiation effects on VLSI geometry MOSFETs fabricated on laser recrystallized SOI wafers

    International Nuclear Information System (INIS)

    The authors have investigated the effects of radiation on the characteristics of NMOS and PMOS FETs having different channel length (1.3 ? m - 5 ? m). The FETs were fabricated on SOI wafers where the silicon (0.5 ? m) film was laser recrystallized. Gammairradiation (up to 200 Krad(Si)) was performed at 300 K while the devices were under bias (+10, 0, -10 volts). Radiation produced severe increases in the NMOS FETs subthreshold leakage currents. Smaller increases with irradiation were observed in the PMOS FET0s subthreshold leakage currents. Radiation caused increases in the PMOS FET0s threshold voltage with the largest shifts occuring for the +10 volts gate bias. The threshold voltage in NMOS devices decreased with exposure to ionizing irradiation. All the observed threshold shifts are consistent with net hole trapping in the SiO2. The authors observed a monotonic dependence of the radiation induced threshold voltage shifts on the channel length of PMOS devices. Smaller threshold shifts were obtained for the shorter channel devices

  17. Thermoluminesence of gamma rays irradiated CaSO4 nanorods doped with different elements

    Science.gov (United States)

    Salah, Numan

    2015-01-01

    Nanorods of calcium sulfate (CaSO4) activated by Ag, Cu, Dy, Eu and Tb were synthesized by the co-precipitation technique. They were irradiated by ?-rays in a wide range of exposures and studied for their thermoluminesence (TL) properties. The as-synthesized samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoluminescence (PL) emission spectra. SEM images show that the samples doped with rare earths elements (i.e. Dy, Eu and Tb) have thinner nanorods than the other samples, while XRD pattern shows a complete crystalline structures in a monoclinic phase. The TL glow curves of these samples show two components. The first one include low temperature glow peaks at around 125 °C, while the second component shows high temperature peaks in the range 230-270 °C. These glow peaks diver from sample to sample by their TL intensity. The TL results are promising, particularly that of Tb and Eu. Tb doped sample is found to be a highly TL sensitive with a prominent glow peak at around 270 °C, while Eu has created very active, high dense electron traps. The later shows quite linear response in the whole studied exposures i.e. 10 Gy-10 kGy. These results show that Eu or Tb doped CaSO4 nanorods might be proper candidates as dosimeters for high doses of ionizing radiations used in irradiation of foods and seeds.

  18. Decomposition of colored wastewater for recycling water by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Utilization of advanced treated water from wastewater treatment plants for the restoration of waterway is in progress to improve the waterside environment. However, the colored wastewater containing molasses pigments, melanoidins, is not decolorized by activated sludge process, and the water can not be applied for recycling water. We have studied the radiation treatment for decolorization of wastewater discharged from baker's yeast factory. The decolorization after decomposition of colored biorefractory organic substances in wastewater, enhancement in biodegradability and effective decrease in values of COD were observed after gammaray irradiation. Although the decrease in values of COD was observed, however chromaticity was not improved after the combined treatment of wastewater by radiation together with activated sludge. The result suggests that it is necessary to find the optimum conditions for stimulation of sludge in the combined treatment. (author)

  19. Alteration of UV primary fluorescence of vital tumor cells following irradiation with neutrons and gamma rays

    International Nuclear Information System (INIS)

    The change of UV primary fluorescence intensity of vital unstained cells of Ehrlich ascites carcinoma after 60Co-gamma and neutron irradiation was investigated. The mean neutron energy was 6.2 MeV. Fluorescence intensity was detected using impulse cytophotometry. The UV intensity of single cells was measured in the spectral range from 300-400 nm. An monotonous increase of dose-effect curves and a maximum at 3.5 Gy (neutrons) and 30 Gy (?-rays) was obtained. The first relevant increase of fluorescence intensity was detected at 0.4 Gy (neutrons) and 0.75 Gy (?-rays). Factors influencing the increase and decrease of primary fluorescence behavior of vital cells are discussed. (author)

  20. Behavior of triterpenes from Maytenus aquifolium Martius ('espinheira santa') upon X- and gamma-rays irradiation

    International Nuclear Information System (INIS)

    The behavior of the triterpenes friedelin and friedelan-3-ol, contained on the leaves of Maytenus aquifolium Martius (Celastraceae), upon several doses of X- and ?-rays (10 to 100 kGy), was investigated by high resolution gas chromatography (HRGC) and high resolution gas chromatography -mass spectrometry (HRGC-MS). The friedelin content has not changed with ?-irradiation, but the content of friedelan-3-ol decreased around 17% at doses of 10, 20 and 40 kGy and around 27% at doses of 60, 80 and 100 kGy. The levels of both triterpenes remained unchanged even at higher X-ray doses. Lupen-3-one was detected by HRGC-MS. (author)

  1. Gamma-ray irradiation synthesis of silk fibroin-coated CdS quantum dots

    International Nuclear Information System (INIS)

    Silk fibroin coated CdS quantum dots (SF-CdS QDs) were successfully synthesized in an aqueous system at room temperature under 60Co ?-ray irradiation. The prepared QDs were characterized by transmission electron microscopy (TEM), energy dispersion spectrometry (EDS), Fourier transform infrared spectrometer(FT-IR), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-vis) and photoluminescence (PL) spectrometry. The synthesized QDs were about 5 nm in diameter with excellent water-solubility. The QDs showed strong visible yellow-green luminescence under UV excitation, at an emission peak of around 538 nm. This method could be conveniently extended to fabricate other nanoparticles coated with silk fibroin. (authors)

  2. Preparation of hydrogels for atopic dermatitis containing natural herbal extracts by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Atopic dermatitis (AD) is a familial and chronic inflammatory pruritic skin disease that affects a large number of children and adults in industrialized countries. It is known that one of the prominent features of AD and chronic pruritus is partially due to the histamine released from mast cell. In this work, hydrogel patches with natural herbal extracts were prepared by 'freezing and thawing', and a gamma irradiation. It showed eminent healing results as a consequence of long-term moisturizing effects and natural herbal extracts on atopic wounds. Besides its non-toxicity and human harmlessness, it can be easily attached to or detached from the skin without any trace and help patients to feel refreshment when attached. Based on this work, the hydrogel patches we made can be potentially used as an alternative remedy for not only pruritus in AD, but other dermatitis.

  3. Gamma-ray irradiation resistance of silver doped GeS2–Ga2S3–AgI chalcohalide glasses

    International Nuclear Information System (INIS)

    Highlights: • The ?-ray irradiation resistance of Ag doped chalcohalide glasses (GeS2–Ga2S3–AgI) has been investigated. • The introduction of silver ions plays a specific role in the modification of the gamma-ray irradiation resistance of glasses. • The sulfur exerts an important effect on the photo-sensitivity of chalcogenide glasses. - Abstract: In the present work, series of silver doped Ge–Ga–S–AgI chalcohalide glasses have been prepared and their optical transmission spectra are compared before and after ?-ray irradiation at different doses. The differential transmission spectra of the irradiated samples with and without Ag doping have been compared to characterize the ?-ray irradiation induced red-shift of electronic absorption and formation of color centers. Ag doping plays an important role in increasing ?-ray irradiation resistance of the chalcohalide glasses due to its specific effect on the valence band and the network structure of glasses

  4. Gamma-ray irradiation resistance of silver doped GeS{sub 2}–Ga{sub 2}S{sub 3}–AgI chalcohalide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Shen, W. [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); ENEA-UTT-MATIRR, Via Anguillarese 301, 00123 Rome (Italy); Baccaro, S.; Cemmi, A. [ENEA-UTT-MATIRR, Via Anguillarese 301, 00123 Rome (Italy); Ren, J. [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhang, Z.; Zhou, Y. [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); ENEA-UTT-MATIRR, Via Anguillarese 301, 00123 Rome (Italy); Yang, Y. [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Chen, G., E-mail: grchen@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2014-06-01

    Highlights: • The ?-ray irradiation resistance of Ag doped chalcohalide glasses (GeS{sub 2}–Ga{sub 2}S{sub 3}–AgI) has been investigated. • The introduction of silver ions plays a specific role in the modification of the gamma-ray irradiation resistance of glasses. • The sulfur exerts an important effect on the photo-sensitivity of chalcogenide glasses. - Abstract: In the present work, series of silver doped Ge–Ga–S–AgI chalcohalide glasses have been prepared and their optical transmission spectra are compared before and after ?-ray irradiation at different doses. The differential transmission spectra of the irradiated samples with and without Ag doping have been compared to characterize the ?-ray irradiation induced red-shift of electronic absorption and formation of color centers. Ag doping plays an important role in increasing ?-ray irradiation resistance of the chalcohalide glasses due to its specific effect on the valence band and the network structure of glasses.

  5. Gamma-ray astronomy

    OpenAIRE

    Pohl, Martin

    2001-01-01

    This paper summarizes recents results in gamma-ray astronomy, most of which were derived with data from ground-based gamma-ray detectors. Many of the contributions presented at this conference involve multiwavelength studies which combine ground-based gamma-ray measurements with optical data or space-based X-ray and gamma-ray measurements. Besides measurements of the diffuse emission from the Galaxy, observations of blazars, gamma-ray bursts, and supernova remnants this pape...

  6. Gamma ray generator

    Science.gov (United States)

    Firestone, Richard B; Reijonen, Jani

    2014-05-27

    An embodiment of a gamma ray generator includes a neutron generator and a moderator. The moderator is coupled to the neutron generator. The moderator includes a neutron capture material. In operation, the neutron generator produces neutrons and the neutron capture material captures at least some of the neutrons to produces gamma rays. An application of the gamma ray generator is as a source of gamma rays for calibration of gamma ray detectors.

  7. Effects of 2.0 Gy of 60Co gamma rays irradiation on rat embryos

    International Nuclear Information System (INIS)

    Pregnant rats of Donryu strain were exposed to a whole-body 60Co ? ray irradiation of a single dose of 2.0 Gy (Dose rate: 0.5 Gy/min) on day 7, 8, 9, 10 or 11 of gestation (sperm day = day 0). The rats were sacrificed on day 18 and the offspring were examined for external and visceral malformations. Malformed embryos occurred between days 7 and 11 with the highest incidence occurring on day 9. Dose with 2.0 Gy increased the rate of resorption or death (52.1 %), in the survivors, caused congenital malformation in a majority of embryos (86.5 %) on day 8 of gestation. There is an increase in malformation (93.3 %) and growth retardation, but no increase in mortality (42.9 %) on day 9 of gestation. Relatively few anomalies resulted from irradiation on day 7 of gestation. The peak day for cardiovascular anomalies occurred on day 9 (88.3 % of all survival embryos) with high levels also occurring on day 8 (86.5 %). Cardiovascular anomalies consisted of VSD, hypoplasia of the pulmonary trunk, coarctation of the aorta, double aortic arch, right aortic arch, riding aorta, complete transposition of the aorta, persistent atrioventricular canal, vascular ring, aberrant right subclavian artery and others. Similar anomalies, but at a lower incidence, were produced by 60Co ? ray at dose levels of 2.0 Gy on day 10 or 11 of gestation. Cases of cleft lip and cleft palate or facial cleft were observed seventeen fetuses on day 9 of gestation (31 %). Exencephaly occu 9 of gestation (31 %). Exencephaly occurred in nine embryos treated on day 9 (16.1 %) and in one embryos treated on day 10. Tail defects appeared with treatment on day 9 with the latter predominating on day 11. The present study show that maximum resorption (52.1 %) was seen with treatment on day 8 whereas the highest rate of malformation (93.3 %) was observed with treatment on day 9. (J.P.N.)

  8. Study of the current-voltage characteristics of a SiC radiation detector irradiated by Co-60 gamma-rays

    International Nuclear Information System (INIS)

    The SiC semiconductor has recently emerged as an attractive material for an ionization radiation detection. A wide bandgap (3.03 eV) and high radiation damage resistance allow for the fabrication of detectors capable of operating at a high-temperature and in high radiation fields. The major aim of our study is to develop a robust detector which will be applied to harsh radiation environments. In this study, we fabricated the SiC radiation detectors and measured the current-voltage characteristics of SiC detectors irradiated by Co-60 gamma-ray source. The I-V curves showed a decrease of the leakage current with increasing dose rate of Co-60 gamma-ray in the 0-100 V bias voltage range

  9. Grafting study of polysulfone polymeric membranes by gamma ray irradiation; Estudo da grafitizacao de membranas polimericas a base de polissulfona por irradiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    Radiation-induced grafting of styrene poli sulfone films were investigated by simultaneous method in solution using gamma-ray from a radio nuclide {sup 60}Co source. The gamma-ray energy of high intensity induced breaking of chemical bonds leading to free radical formation. The radical start a conventional polymerization sequence comparable with that obtained with a chemical catalyst acting as initiator. The effects of grafting conditions such as irradiation total dose, dose rate and addition of cross linking agent, were studied by means of morphology analysis, thermal degradation and crystallinity. After the grafting reaction, the membranes were submitted to an exhaustive extraction with solvent to remove the polystyrene homopolymer formed. The degree of grafting (DOG) was analyzed by percentage of weight increase. As a result, the reaction always follows the same pattern: DOG increases rapidly initially whilst propagation is the main reaction, then more slowly as termination becomes more frequent. (author)

  10. Oxygen formation in gamma-ray irradiation of Fe2+ -Cu2+ solutions

    DEFF Research Database (Denmark)

    Bjergbakke, Erling; Hart, E.J.

    1971-01-01

    The mechanism of O2 formation has been studied in 60 Co ?-ray-irradiated Fe(II) + Cu(II) solutions at 0.01 N HClO4 and at 0.01, 0.08, and 0.80 N H2 SO4. In the H2 SO4 system, ${\\rm G}({\\rm O}_{2})$ rises to plateau levels near 0.02 as the ${\\rm CuSO}_{4}/{\\rm FeSO}_{4}$ ratio increases. The plateau value diminishes slightly and is displaced toward higher ${\\rm CuSO}_{4}/{\\rm FeSO}_{4}$ ratios with increasing acidity. The perchlorate system differs from the sulfate only at high ${\\rm Cu}({\\rm ClO}_{4})/{\\rm Fe}({\\rm ClO}_{4})_{2}$ ratios where $G({\\rm O}_{2})$ rises to 0.10. The O2 yield of 0.02 is not derived from "spur" HO2, OH, H2 O2 or O2, although the increase in $G({\\rm O}_{2})$ above this level in the perchlorate system is attributed to H2 O2. "Spur" O atoms are postulated as the source of O2 with the yield, $G({\\rm O}_{2})$ = 0.02.

  11. Simulation of survival curves in several bacteria irradiated with ultraviolet and gamma rays

    International Nuclear Information System (INIS)

    Although ultraviolet and gamma sterilization were routinely used, D10-values and D99.9-values have been used in actual applications. However, our preliminary results showed that UV-survival curves were sigmoidal and ?-curves were exponential having a shoulder at beginning in many strains. This study was conducted to make clear the reason of occurence of the sigmoid in UV survival curves, at first. Both survival curves of spore cells and vegetable cells in Bacillus subtilis against UV-irradiation are shown with the same sigmoidal pattern. It is clarified that the difference in sensibilities of vegetative and spore cells could not account for the presence of tails. The UV sterilized data have been simulated by adapting a multi hit theory and taking into account the decrease in UV-intensity in liquid suspensions due to Lambert's law. These also follows that the above multi-hit simulation is effective for the ? data and four hits are best fitted to the observed data in both cases of bacteria and fungi. From these results, it is demonstrated that if D10-value and L-value are used as indices for practical sterilization and if a target area and a hit number, a parameter of penetration in UV sterilization are considered, the sterilization level will become more accurate than that as determined by D10- and D99.9-values currently used. (author)

  12. Major soluble proteome changes in Deinococcus deserti over the earliest stages following gamma-ray irradiation

    Directory of Open Access Journals (Sweden)

    Dedieu Alain

    2013-01-01

    Full Text Available Abstract Background Deinococcus deserti VCD115 has been isolated from Sahara surface sand. This radiotolerant bacterium represents an experimental model of choice to understand adaptation to harsh conditions encountered in hot arid deserts. We analysed the soluble proteome dynamics in this environmentally relevant model after exposure to 3 kGy gamma radiation, a non-lethal dose that generates massive DNA damages. For this, cells were harvested at different time lapses after irradiation and their soluble proteome contents have been analysed by 2-DE and mass spectrometry. Results In the first stage of the time course we observed accumulation of DNA damage response protein DdrB (that shows the highest fold change ~11, SSB, and two different RecA proteins (RecAP and RecAC. Induction of DNA repair protein PprA, DNA damage response protein DdrD and the two gyrase subunits (GyrA and GyrB was also detected. A response regulator of the SarP family, a type II site-specific deoxyribonuclease and a putative N-acetyltransferase are three new proteins found to be induced. In a more delayed stage, we observed accumulation of several proteins related to central metabolism and protein turn-over, as well as helicase UvrD and novel forms of both gyrase subunits differing in terms of isoelectric point and molecular weight. Conclusions Post-translational modifications of GyrA (N-terminal methionine removal and acetylation have been evidenced and their significance discussed. We found that the Deide_02842 restriction enzyme, which is specifically found in D. deserti, is a new potential member of the radiation/desiccation response regulon, highlighting the specificities of D. deserti compared to the D. radiodurans model.

  13. Late effects of protracted whole-body irradiation of beagles by cobalt-60 gamma rays

    International Nuclear Information System (INIS)

    So that a stronger basis for extrapolation of low-level radiation effects to man can be provided, existing data from small laboratory animals are being supplemented by studies in a longer lived animal, the dog. Beagle dogs are exposed to continuous cobalt-60 irradiation either throughout life or until predetermined total doses are accumulated. The radiation-specific excess-mortality rate and associated causes of death will be related to both dose rate and total dose. The ongoing studies also emphasize the pathogenesis of myelogenous leukemia. At dose rates of 3.75 to 26.25 rads/day, given continuously, responses were consistent, highly dose-rate dependent, and limited primarily to the hematopoietic system. At rates as low as 0.3 rad/day, the hematopoietic system is still the limiting factor for survival, but below 3.75 rads/day present evidence suggests that the responses are independent of dose rate. Longitudinal studies of peripheral blood and bone marrow detected four preclinical phases of myelogenous leukemia. These phases were characterized by standard hematologic end points, ultrastructural features, in vitro cloning assays, and the acute radiation sensitivity of stem cells. Results suggest that an induced error-prone repair mechanism is the basis for the onset of radiation-induced myelogenous leukemia. Interim data from dogs given terminated exposures suggest that the types of tumors and times to death are different from controls but the numbers of tumors are nm controls but the numbers of tumors are not yet greater than in controls. 26 refs., 12 figs., 5 tabs

  14. Low Dose Gamma Irradiation Potentiates Secondary Exposure to Gamma Rays or Protons in Thyroid Tissue Analogs

    Energy Technology Data Exchange (ETDEWEB)

    Green, Lora M

    2006-05-25

    We have utilized our unique bioreactor model to produce three-dimensional thyroid tissue analogs that we believe better represent the effects of radiation in vivo than two-dimensional cultures. Our thyroid model has been characterized at multiple levels, including: cell-cell exchanges (bystander), signal transduction, functional changes and modulation of gene expression. We have significant preliminary data on structural, functional, signal transduction and gene expression responses from acute exposures at high doses (50-1000 rads) of gamma, protons and iron (Green et al., 2001a; 2001b; 2002a; 2002b; 2005). More recently, we used our DOE funding (ending Feb 06) to characterize the pattern of radiation modulated gene expression in rat thyroid tissue analogs using low-dose/low-dose rate radiation, plus/minus acute challenge exposures. Findings from these studies show that the low-dose/low-dose rate “priming” exposures to radiation invoked changes in gene expression profiles that varied with dose and time. The thyrocytes transitioned to a “primed” state, so that when the tissue analogs were challenged with an acute exposure to radiation they had a muted response (or an increased resistance) to cytopathological changes relative to “un-primed” cells. We measured dramatic differences in the primed tissue analogs, showing that our original hypothesis was correct: that low dose gamma irradiation will potentiate the repair/adaptation response to a secondary exposure. Implications from these findings are that risk assessments based on classical in vitro tissue culture assays will overestimate risk, and that low dose rate priming results in a reduced response in gene expression to a secondary challenge exposure, which implies that a priming dose provides enhanced protection to thyroid cells grown as tissue analogs. If we can determine that the effects of radiation on our tissue analogs more closely resemble the effects of radiation in vivo, then we can better estimate the risks and modify assign limits to radiation worker and astronauts. Additionally, confirmation that tissue analogs represent a realistic in vivo response to radiation will allow scientists to perform tissue relevant experiments without the expense of using animals. Confirmation of the in vivo approximation of our model will strengthen our findings from the recent completion of our DOE funding which is the subject of the current proposal.

  15. Dense Electron-Positron Plasmas and Ultra-Intense Bursts of Gamma-Rays from Laser-Irradiated Solids

    CERN Document Server

    Ridgers, C P; Duclous, R; Kirk, J G; Bennett, K; Arber, T D; Robinson, A P L; Bell, A R

    2012-01-01

    In simulations of a 10PW laser striking a solid we demonstrate the possibility of producing a pure electron-positron plasma by the same processes as those thought to operate in high-energy astrophysical environments. A maximum positron density of 10^26/m^3 is achieved, seven orders of magnitude greater than achieved in previous experiments. Additionally, 35% of the laser energy is converted to a burst of gamma-rays of intensity 10^22W/cm^2, potentially the most intense gamma-ray source available in the laboratory. This absorption results in a strong feedback between both pair and gamma-ray production and classical plasma physics in the new `QED-plasma' regime.

  16. High gamma-rays irradiation tests of critical components for ITER (International Thermonuclear Experimental Reactor) in-vessel remote handling system

    Energy Technology Data Exchange (ETDEWEB)

    Obara, Kenjiro; Kakudate, Satoshi; Oka, Kiyoshi [Department of Fusion Engineering Research, Naka Fusion Research Establishment, Japan Atomic Energy Research Institute, Naka, Ibaraki (Japan)] [and others

    1999-02-01

    In ITER, the in-vessel remote handling is inevitably required to assemble and maintain the activated in-vessel components due to deuterium and tritium operation. Since the in-vessel remote handling system has to be operated under the intense of gamma ray irradiation, the components of the remote handling system are required to have radiation hardness so as to allow maintenance operation for a sufficient length of time under the ITER in-vessel environments. For this, the Japan, European and Russian Home Teams have extensively conducted gamma ray irradiation tests and quality improvements including optimization of material composition through ITER R and D program in order to develop radiation hard components which satisfy the doses from 10 MGy to 100 MGy at a dose rate of 1 x 10{sup 6} R/h (ITER R and D Task: T252). This report describes the latest status of radiation hard component development which has been conducted by the Japan Home Team in the ITER R and D program. The number of remote handling components tested is about seventy and these are categorized into robotics (Subtask 1), viewing system (Subtask 2) and common components (Subtask 3). The irradiation tests, including commercial base products for screening, modified products and newly developed products to improve the radiation hardness, were carried out using the gamma ray irradiation cells in Takasaki Establishment, JAERI. As a result, the development of the radiation hard components which can be tolerable for high temperature and gamma radiation has been well progressed, and many components, such as AC servo motor with ceramics insulated wire, optical periscope and CCD camera, have been newly developed. (author)

  17. High gamma-rays irradiation tests of critical components for ITER (International Thermonuclear Experimental Reactor) in-vessel remote handling system

    International Nuclear Information System (INIS)

    In ITER, the in-vessel remote handling is inevitably required to assemble and maintain the activated in-vessel components due to deuterium and tritium operation. Since the in-vessel remote handling system has to be operated under the intense of gamma ray irradiation, the components of the remote handling system are required to have radiation hardness so as to allow maintenance operation for a sufficient length of time under the ITER in-vessel environments. For this, the Japan, European and Russian Home Teams have extensively conducted gamma ray irradiation tests and quality improvements including optimization of material composition through ITER R and D program in order to develop radiation hard components which satisfy the doses from 10 MGy to 100 MGy at a dose rate of 1 x 106 R/h (ITER R and D Task: T252). This report describes the latest status of radiation hard component development which has been conducted by the Japan Home Team in the ITER R and D program. The number of remote handling components tested is about seventy and these are categorized into robotics (Subtask 1), viewing system (Subtask 2) and common components (Subtask 3). The irradiation tests, including commercial base products for screening, modified products and newly developed products to improve the radiation hardness, were carried out using the gamma ray irradiation cells in Takasaki Establishment, JAERI. As a result, the development of the radiation hard components which can be tolerable for high temperature and gamma radiation has been well progressed, and many components, such as AC servo motor with ceramics insulated wire, optical periscope and CCD camera, have been newly developed. (author)

  18. Effect of Irradiation of 60CO Gamma Rays on Growth of Garlic (Allium Sativum L) Plants Cv. Lumbu Hijau at Low Land Area

    International Nuclear Information System (INIS)

    Garlic originally come from the sub tropical area. In Indonesia, garlic is grown generally in high land area with an altitude between 1000 - 1600 m above sea level. Therefore, the area for growing and producing garlic is limited. Besides, genetic variation of garlic is very narrow since garlic belongs to vegetatively propagated crops. An effort for increasing genetic variation of garlic was done by exposing garlic cloves to gamma rays in order to obtain garlic mutant lines adapted to low land area. Garlic cloves were exposed to different doses of gamma rays 0 (untreated) 2, 4, 6, 8 and 10 Gy at the Centre for Research and Development of Isotope and Radiation Technology. Each dose consisted of 150 garlic cloves. Untreated and irradiated garlic cloves were grown at Bandar Buat Experimental Station (50 m above sea level), Padang, West Sumatera. The experiment was arranged in a randomized block design with three replication. The parameter observed were percentage of grown plants and survival harvested plants, plant height, leaf number, chlorophyll content, number of stomata, plant age, number of cloves per bulbs, fresh, dry weight and diameter of bulbs. The result indicated that the dose of gamma rays 6 Gy is an advantage dose for obtaining well adapted garlic mutant lines in the low land area. (author)

  19. Formation of fine palladium particles from palladium sulfate aqueous solution by gamma-ray irradiation as observed by electronic absorption spectroscopy and dynamic light scattering

    International Nuclear Information System (INIS)

    To find a way of probing the coagulation of metal particles formed by the irradiation of metallic ion solution without surfactant, palladium sulfate aqueous solution was irradiated with gamma rays (11.2kGy/h, 10kGy) and turbidity change of the solution after irradiation was followed by optical density at 700nm using a UV-visible spectrophotometer. The particle diameter distribution was monitored by dynamic light scattering. The results indicate that the turbidity decreased monotonously, and that there are major peaks in the distributions, one with diameters in the 400-800nm region and the other with diameters in the 1500-2500nm. The density of the particles seems to be smaller than that of bulk palladium metal. Similar experiments were carried out on palladium-silver sulfate solution. (author)

  20. Effect of gamma ray irradiation on the structural and electrical transport properties of PrFe{sub 1?x}Mn{sub x}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Sultan, Khalid, E-mail: ksbhat.phy@gmail.com; Ikram, M., E-mail: ksbhat.phy@gmail.com [Department of Physics, National Institute of Technology Hazratbal, Srinagar-190006, Jammu and Kashmir (India); Asokan, K. [Material Science Division, Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi-110067 (India)

    2014-04-24

    The effect of gamma ray irradiation on the structural and transport properties of polycrystalline bulk samples of PrFe{sub 1?x}Mn{sub x}O{sub 3} (x = 0.0, 0.1, 0.5) were investigated. The samples were synthesized by solid state reaction method and exposed to {sup 60}Co gamma radiation to accumulated dose of 625 KGy. From the Raman study, the modes exhibit a blue shift with broadening of spectral features in the irradiated samples. The dielectric constant (??) was also studied as a function of frequency. The dielectric constant and ac conductivity increases with Mn doping but decrease on irradiation. Exposure to gamma radiation results in substantial modification in the physical properties of these compounds.

  1. Assessment of radioprotective effects of amifostine on human lymphocytes irradiated in vitro by gamma-rays using cytokinesis-blocked micronucleus assay

    International Nuclear Information System (INIS)

    A radioprotective effect of amifostine as well as its ability to modulate the level of spontaneous and gamma-rays-induced genetic changes on human peripheral blood lymphocytes has been investigated. Amifostine, known as a potent radical scavenger, has been introduced as the most effective radioprotector, yet it is not completely approved for the clinical use. However, further in vitro and clinical studies are needed to clarify its mechanisms of action. Materials and Methods: Whole blood samples from healthy donors were exposed to various doses of gamma-rays. Lymphocytes in cultures were treated with amifostine at different concentrations (2, 4 and 6 m M) in the presence or in the absence of 1 U/ml alkaline phosphatase before or after gamma-irradiation. Standard procedure for the cytokinesis-block micronucleus (CBMN) assay was used to assess the effect of amifostine on radiation induced micronucleus in bi nucleate lymphocytes. Results: Irradiated blood samples showed an increase in the total number of micronuclei (MN) significantly different from controls (p<0.05). However, pre-treatment of lymphocytes with amifostine in the presence of alkaline phosphatase, 15 minutes before irradiation, led to a significant decrease in the frequencies of MN and cells with more than one MN (p< O.05). Antifeminist, in its own, produced little or no protection. However, the addition of amifostine with alkaline phosphatase to the cell cultures 15 minutes after irradiation produced substanminutes after irradiation produced substantial radioprotection significantly different from the frequencies of MN induced by radiation alone (p< O.05). Conclusion: Results clearly indicated that gamma-rays induced MN in lymphocytes in a dose dependent manner. The highest protective effect was achieved when amifostine was phosphorylated by alkaline phosphatase and present before irradiation in the cellular environment, was indicating its radical scavenging mechanism of radioprotection. Since the administration of amifostine after irradiation also led to a considerable decrease in the frequency of radiation induced MN, other mechanisms such as induction of cell cycle delay and hence influencing DNA repair, might be involved in radioprotection by amifostine

  2. Caffeine sensitization of cultured mammalian cells and human lymphocytes irradiated with gamma rays and fast neutrons: a study of relative biological effectiveness in relation to cellular repair

    International Nuclear Information System (INIS)

    The sensitizing effects of caffeine were studied in baby hamster kidney (BHK-21) cells and human lymphocytes following irradiation with gamma rays and fast neutrons. Caffeine sensitization occurred only when log-phase BHK cells and mitogen-stimulated lymphocytes were exposed to the two radiations. Noncycling (confluent) cells of BHK resulted in a shouldered survival curve following gamma irradiation while a biphasic curve was obtained with the log-phase cells. Survival in the case of lymphocytes was estimated by measurement of [3H]thymidine uptake. The relative biological effectiveness (RBE) of fast neutrons was found to be greater at survival levels corresponding to the resistant portions of the survival curves (shoulder or resistant tail). In both cell types, no reduction in RBE was observed when caffeine was present, because caffeine affected both gamma and neutron survival by the same proportion

  3. Effect of dose-rate and age at irradiation on cancer development in Sprague-Dawley rats exposed to gamma rays

    International Nuclear Information System (INIS)

    The probability that rats develop tumors following a 3 Gy exposure to gamma rays from cobalt 60 was observed to depend on age at exposure and on dose rate. Dose rate reduction by a factor of 60 decreased the carcinogenic incidence (mainly carcinomas) by a factor of about 5. Lifetime excess of malignant neoplasia decreased by a factor of about 10 in 9 month-old rats as compared to animals irradiated in utero. The 3-month age group developed slightly fewer cancers than the group irradiated in utero, and tumor location was different. The higher incidence of tumors following in utero exposure was dependent to the high sensitivity of brain and gonads during organogenesis. (author)

  4. Dense Electron-Positron Plasmas and Ultra-Intense Bursts of Gamma-Rays from Laser-Irradiated Solids

    OpenAIRE

    Ridgers, C. P.; Brady, C. S.; Duclous, R.; Kirk, J. G.; Bennett, K.; Arber, T. D.; Robinson, A. P. L.; Bell, A. R.

    2012-01-01

    In simulations of a 10PW laser striking a solid we demonstrate the possibility of producing a pure electron-positron plasma by the same processes as those thought to operate in high-energy astrophysical environments. A maximum positron density of 10^26/m^3 is achieved, seven orders of magnitude greater than achieved in previous experiments. Additionally, 35% of the laser energy is converted to a burst of gamma-rays of intensity 10^22W/cm^2, potentially the most intense gamma...

  5. Comparison of electron beam and gamma ray irradiations effects on ruminal crude protein and amino acid degradation kinetics, and in vitro digestibility of cottonseed meal

    International Nuclear Information System (INIS)

    This study was conducted to compare effects of electron beam (EB) and gamma ray (GR) treatments at doses of 25, 50 and 75 kGy on ruminal degradation kinetics of crude protein (CP), amino acid (AA), and in vitro digestibility of cottonseed meal (CSM). Ionizing radiations of EB and GR had significant effects (P0.05). Irradiation processing caused decrement in AA degradation after 16 h of ruminal incubation (P<0.05). EB irradiation was more effective than GR irradiation in lessening the ruminal degradability of AA (P<0.05). EB and GR treatments at a dose of 75 kGy increased in vitro digestibility of CSM numerically. This study showed that EB could cause CP and AA bypass rumen as well as GR. Therefore, ionizing irradiation processing can be used as an efficient method in improving nutritional value of CSM. - Highlights: ? Irradiation was effective on reducing ruminal degradability of cottonseed meal. ? Ionizing radiations, especially electron beam, lessened ruminal degradability of amino acid substantially. ? Irradiation processing could be used as a safe and efficient method in improving nutritional value of cottonseed meal.

  6. Feasibility of applying gamma irradiation as disinfestation technique on date fruits in respect to nutritional value that is affected by disinfesting gamma ray doses

    International Nuclear Information System (INIS)

    Infested and non-infested dry date fruits (Phonex dactylifera), Abrimi variety (9.2% moisture), with Ephestia cautella Walker were irradiated for 0, 15, 20 and 40 Krad gamma ray doses emitted from Co-60 source with 1.36 x 10-rad/h. as a dose rate. Irradiated fruits were stored at room temperature, at 20-250C and 85-95% R.H., in packages to avoid reinfestation. A dose of 20 Krad is 100 percent effective in preventing the emergency of eggs, larva, and pupae in fruits as reflected by zero per cent emergency count for live adults. Also, this dose was found to be lethal for adult stage of the insect. On the other hand, 2 Krad dose does not produce significant changes in the nutritional qualities of fruits, as measured by chemical analytical means for carbohydrates, protein and amino acids, directly after irradiation as well as at 2, 4 and 6 months storage. The triangular tests show that irradiation treatments even with 4 Krad exerted no determinal effect upon the sensory qualities of stored irradiated date fruits. These results point out the feasibility of applying gamma irradiation, 20 Krad, as disinfestation technique against Ephestia cautella Walker in dry date fruits without exerting any effect on the nutritional value

  7. On the decrease of ultimate elongation of gum elastomer by irradiation

    International Nuclear Information System (INIS)

    The reason why the ultimate elongation of gum elastomer decreases by irradiation was studied. The sample used is tetrafluoroethylenepropylene copolymer vulcanized which is a heat resistant elastomer. The sample was irradiated by a electron beam at room temperature. Cross-linking predominate in the operation. (Case 1) Scission predominant condition (Case 2) was given by irradiation of Co-60 ? ray at 100 deg C. Alternative irradiation of ? ray and electron beam under above condition can keep the original cross-linking density by the appropriate choice of each of the doses. (Case 3) The three cases mentioned above involve all of the cases of radiation induced aging of elastomers. Therefor, the following explanation for three cases shows the reason why the ultimate elongation of gum elastomer decreases by irradiation. Case 1. Cross-linking predominant condition. Ultimate elongation is proportional to -0.5 power of the dose. This fact can be explicable by the model of Buche, i.e. the breaking of a short chain causes another to break and that so on throughout the whole sample. Case 2. Chain scission predominant condition. Ultimate elongation increases by irradiation for a certain dose. This fact can understand by the model of Buche. But from a certain dose ultimate elongation does not increase. In the period the structure of the sample turned to be the same structure as the low molecular weight amorphose polymer vulcanized. Case 3. Rate of cross-linking and scission is the same. The average chain length does not chainge in the condition. But the distribution of chain length became wider and wider by irradiation. The increase of short chain result the decrease in ultimate elongation. (author)

  8. Gamma rays control coding moths

    International Nuclear Information System (INIS)

    Gamma rays are being tested as a means of controlling codling moths, Cydia pomonella (L.), under fruit storage conditions where fumigation will not work. Preliminary tests have shown that gamma radiation kills all exposed codling moth larvae, including larvae in the dormant stage. There is no carryover of radiation in the fruit and minimal effect on the fruit. Gamma irradiation of food is considered safe for human consumption at doses of 1 kilogray (10 kilorads) or less

  9. Gamma rays control coding moths

    Energy Technology Data Exchange (ETDEWEB)

    Yarris, L.

    Gamma rays are being tested as a means of controlling codling moths, Cydia pomonella (L.), under fruit storage conditions where fumigation will not work. Preliminary tests have shown that gamma radiation kills all exposed codling moth larvae, including larvae in the dormant stage. There is no carryover of radiation in the fruit and minimal effect on the fruit. Gamma irradiation of food is considered safe for human consumption at doses of 1 kilogray (10 kilorads) or less.

  10. Gamma Ray Bursts

    OpenAIRE

    Savchenko, Volodymyr

    2012-01-01

    This thesis presents observational and theoretical studies of the Gamma-ray bursts. Gamma-ray bursts are thought to be associated with events of violent gravitational collapse either at the end of the evolution of massive stars or after merging of neutron stars and black holes. The mechanism responsible for the emission of the gamma-rays as well as associated radiation from radio to X-ray is not yet understood. In the scope of this thesis observations are used to critically test the gamma-ray...

  11. Comparison of base substitutions in response to nitrogen ion implantation and 60Co-gamma ray irradiation in Escherichia coli

    Scientific Electronic Library Online (English)

    Xie, Chuan-Xiao; Xu, An; Wu, Li-Jun; Yao, Jian-Min; Yang, Jian-Bo; Yu, Zeng-Liang.

    Full Text Available To identify the specificity of base substitutions, a novel experimental system was established based on rifampicin-resistant (Rif r) mutant screening and sequencing of the defined region of the rpoB gene in E. coli. We focused on comparing mutational spectra of base substitutions induced by either l [...] ow energy nitrogen ion beam implantation or 60Co-gamma rays. The most significant difference in the frequency of specific kinds of mutations induced by low energy nitrogen ion beam was that CG ®TA transitions were significantly increased from 32 to 46, AT ®TA transversions were doubled from 7 to 15 in 50 mutants, respectively. The preferential base substitutions induced by nitrogen ion beam implantation were CG ®TA transitions, AT ®GC transitions, AT ®TA transversions, which account for 92.13% (82/89) of the total. The mutations induced by 60Co-gamma rays were preferentially GC ®AT and AT ®GC transitions, which totaled 84.31% (43/51).

  12. Effects of gamma-ray irradiation on interface states and series-resistance characteristics of BiFeO3 MOS capacitors

    International Nuclear Information System (INIS)

    The effects of radiation on the electrical-interface-state density (Dit) and series resistance (Rs) characteristics of BiFeO3 MOS capacitors were studied in this work. To study the response of MOS devices to gamma irradiation over a range of doses, MOS samples were irradiated using a Co-60 gamma-ray source from 0.5 to 16 grays at a dose rate of 0.0030 Gy/s. C–V and G/?–V measurements were recorded prior to and after irradiation at high (1 MHz) frequency. The effects of the radiation were determined from analysis of the C–V and G/?–V curves. A slightly decrease in the Rs values with increasing irradiation dose was observed. The total interface-state density was found to decrease because of the reordering and restructuring of radiation-induced defects in the MOS capacitors. The experimental results indicate that the electrical Rs and Dit characteristics of BiFeO3 MOS capacitors depend on the gamma-irradiation dose, and the calculated densities of the interface states are on the order of 1011 eV?1 cm?2. However, the calculated Dit values are not high enough to pin the Fermi level of the Si substrate and thereby corrupt device operation over the given dose range

  13. Effects of gamma-ray irradiation on interface states and series-resistance characteristics of BiFeO{sub 3} MOS capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Kaya, Senol, E-mail: senolkaya52@gmail.com [Physics Department, Abant Izzet Baysal University, 14280 Bolu (Turkey); Nuclear Radiation Detectors Research and Development Center, 14280 Bolu (Turkey); Aktag, Aliekber [Physics Department, Abant Izzet Baysal University, 14280 Bolu (Turkey); Nuclear Radiation Detectors Research and Development Center, 14280 Bolu (Turkey); Yilmaz, Ercan [Physics Department, Abant Izzet Baysal University, 14280 Bolu (Turkey); Nuclear Radiation Detectors Research and Development Center, 14280 Bolu (Turkey); Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland)

    2014-01-15

    The effects of radiation on the electrical-interface-state density (D{sub it}) and series resistance (R{sub s}) characteristics of BiFeO{sub 3} MOS capacitors were studied in this work. To study the response of MOS devices to gamma irradiation over a range of doses, MOS samples were irradiated using a Co-60 gamma-ray source from 0.5 to 16 grays at a dose rate of 0.0030 Gy/s. C–V and G/?–V measurements were recorded prior to and after irradiation at high (1 MHz) frequency. The effects of the radiation were determined from analysis of the C–V and G/?–V curves. A slightly decrease in the R{sub s} values with increasing irradiation dose was observed. The total interface-state density was found to decrease because of the reordering and restructuring of radiation-induced defects in the MOS capacitors. The experimental results indicate that the electrical R{sub s} and D{sub it} characteristics of BiFeO{sub 3} MOS capacitors depend on the gamma-irradiation dose, and the calculated densities of the interface states are on the order of 10{sup 11} eV{sup ?1} cm{sup ?2}. However, the calculated D{sub it} values are not high enough to pin the Fermi level of the Si substrate and thereby corrupt device operation over the given dose range.

  14. Permeability Properties of Commercial Sealing Elastomers to Light Gases with and Without Irradiation

    International Nuclear Information System (INIS)

    Elastomers are commonly used as sealing materials for applications at moderate vacuum levels. Use of elastomeric seals in ITER processing systems without any other path barrier is unacceptable from tritium confinement aspects and with safety operation. Alternative sealing methods make part of intense R-and-D efforts for root fore-pumping systems in ITER. A large variety of elastomer materials are available in the market. Gas permeability performance of elastomers are known to depend on composition and other basic properties. Such differences can lead to orders of magnitude for He or H-isotopes permeabilities justifying a systematic experimental study for ranges of interest (0-1 bar, T oC). Radiation rapidly induces hardening and other property modifications, hence performance in radiation degrading environments of their sealing properties requires additional research. The screening of available commercial grades of diverse elastomeric membranes have been performed tested in the gas permeation cell rig developed in CIEMAT for out-of-irradiation qualification and compared with measurements done in a permeation cell coupling the Van de Graaff 2 MeV e- beam facility under ionizing radiation. Time lag measurement through membranes are obtained with and without irradiation. Evidenced differences in transport magnitudes are discussed in terms of composition and elastomer microstructure. Permeability values, gas pressure dependencies and transport domains are made explicit and discussed. (author)

  15. Morphogenetical studies on the M2- and M3-populations of wheat (Triticum aestivum ssp. vulgare L.) after seed irradiation with gamma rays

    International Nuclear Information System (INIS)

    This study deals with the irradiation induced variability in five quantitative traits of wheat. Various statistical parameters and genetic estimates were used herein to determine the magnitude of heritable and non-heritable components of variance in two successive generations (M2 and M3) after treating the seeds of a pure line of the Egyptian hexaploid wheat variety 'Giza 155' with different gamma ray doses. Results indicated a generalized reduction in the mean value of these characters observed in both generations as compared to the mother stock. However, great variability was obtained in both generations more apparent in M3 than M2. Phenotypical correlations, genotypical correlations, and heritability estimates of these characters exhibited high values. The results were represented and discussed. Conclusions were drawn and radiobiological concepts were used for better understanding of the basic feature of radiaton induced mutations. (orig.)

  16. Gamma-ray sources

    International Nuclear Information System (INIS)

    Results are presented from an analysis of the celestial gamma-ray fine-scale structure based on over half of the data which may ultimately be available from the COS-B satellite. A catalogue consisting of 25 gamma-ray sources measured at energies above 100 MeV is presented. (Auth.)

  17. Effects of glucose irradiated by high doses of 60cobalt gamma rays, and of some products of glucose radiolysis on the growth of Jerusalem Artichoke tissue and potato shoots culture in vitro

    International Nuclear Information System (INIS)

    Glucose, irradiated in dry conditions by gamma rays from 5.105 to 107 rad, and incorporated into culture medium, inhibits growth and, simultaneously, increases rhizogenesis of Jerusalem Artichoke tissue in culture. Tuberisation of potato shoots grown in vitro is delayed and partially inhibited. Some substances which result from radiolysis of sugars give the same results, but only at higher concentrations

  18. 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)

    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/cm3 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)

  19. Inelastic gamma ray logging system

    International Nuclear Information System (INIS)

    An illustrative embodiment of the invention includes a system for providing inelastic neutron gamma ray measurements in a well borehole. A pulsed neutron source is used to irradiate earth formations in the vicinity of the borehole with 14 MeV neutrons. Gamma rays resulting from the inelastic scattering of these fast neutrons are detected by an encapsulated liquid scintillator used in conjunction with a photomultiplier. The resulting representative voltage pulses are input to pulse height analyzing apparatus having energy windows located to embrace the Compton distributions associated with calcium, silicon, oxygen and carbon. The number of counts occurring in each of these energy regions may then be interpreted in terms of quantities of interest with respect to the formations in the borehole vicinity

  20. Effects of gamma-ray and UV irradiation on the abnormal aggregation of proteins, and study of repair and protection mechanism

    International Nuclear Information System (INIS)

    Presented are following 7 Studies on the title subject. Abnormal Protein Aggregation and Amino Acid Racemization by Radiation and UV-ray, report the effects of artificial replacement of Asp76 in 70-88th residues of alphaA-crystallin (aA-cry) to L-alpha, L-beta, D-alpha and D-beta/aspartic acid on the properties of the peptide. The hydrophobicity, circular dichroism and insulin aggregation are greatly altered by the isomerization. Analysis of Radiation-induced Structural and Functional Changes around the Aspartic Acid Residues in a Protein, report an attempt to develop a method to prepare the protein with isomerized Asp residue at a specific site of aA-cry with protein ligation, which is unsuccessful. Radiation-induced Damage of Biomolecules and Its Protective Mechanism, report the effect of gamma-ray on linolenic acid and its modification by beta-carotene as carotenoids localize in the membrane lipid and participate in the radiation resistance of bacteria. The pigment is suggested to work protective against damages of biomolecules and to be under strict regulation for its intracellular level. Modeling of D-aspartic Acid Accumulation in a Protein and Its Mechanistic Regulation by the Degrading Enzyme of the Amino Acid, report the role of D-aspartyl endopeptidase, found by authors (DAEP) and dynamics of D-Asp containing protein in superoxide dismutase-deleted mice and in HepG2 cells exposed to H2O2. DAEP is suggested to be damaged by the oxidizing stress, which results ed by the oxidizing stress, which results in the accumulation of D-Asp containing protein possibly leading to acceleration of senescence. Dynamics and Working Mechanism of a Complicated and Huge Protein Complex, report the analysis of yeast 20S and 26S proteasome assembly using the diffusion, X-ray and small-angle neutron scattering. In Situ Observation and Analysis of Dynamics of Aggregation/Dissociation of Proteins, report that the subunit exchange between 1H- and 2H-double rings of each 7-aggregated ring of proteasome alpha7 subunit is measurable by small-angle neutron scattering alone. Comparison of Conformational Changes of Tryptophanase Induced by Ammonium Phosphate and Gamma-ray Irradiation, report that tryptophanase becomes active to D-tryptophan when exposed to the phosphate salt, but does not by 138-1106 Gy gamma ray despite a circular dichroism shift. (T.T.)

  1. Gamma-ray Irradiation Impairs Dendritic Cell Migration to CCL19 by Down-regulation of CCR7 and Induction of Cell Apoptosis

    Directory of Open Access Journals (Sweden)

    Cong Liu, Jin Lin, Luqian Zhao, Yanyong Yang, Fu Gao, Bailong Li, Jianguo Cui, Jianming Cai

    2011-01-01

    Full Text Available Dendritic cells (DCs are the most potent antigen-presenting cells and play a crucial role in the regulation of immune response and migration of DCs into secondary lymphoid tissues also play an important role in the initiation of innate and adaptive immunity. Radiation therapy is now a routine treatment for certain types of cancer and over 20 percent of cancer patients will require radiation therapy during the treatment of their disease. However, the influence of ionizing irradiation on the migratory ability of DCs is largely unknown. In this article, we report that ? ray irradiation can significantly inhibit LPS-triggered up regulation of CCR7 expression and PGE2 production by DC, thus impairing DC migration towards CCL19 in vitro and in vivo. Moreover, ? ray exposed DC also displayed an increased apoptosis rate and decreased cell viability. Furthermore, we demonstrate that exogenous PGE2 can partly reduce the gamma-ray induced migratory impairment and restored CCR7 expression of DC. Our work suggests that ? irradiation affects DC function at multiple steps during the immune response including DC migration, and that PGE2, via control of CCR7 expression, is an important regulator of DC migration.

  2. Gamma-ray bursts

    International Nuclear Information System (INIS)

    The discovery of visible light from gamma-ray bursts has revealed that these puzzling objects lie among the most distant quasars and galaxies in the universe, while radio observations have highlighted their ultrarelativistic nature GAMMA-RAY bursts are one of the top unsolved mysteries in astrophysics, alongside such burning issues as the nature of dark matter and the cosmological constant. We have known of the existence of gamma-ray bursts for over 25 years, but these short flashes of gamma rays have defied all our attempts to understand their causes and origin. New clues to the mystery were provided on 28 February 1997, when the BeppoSAX satellite located a gamma-ray burst more quickly and precisely than ever before. This allowed astronomers to image the burst, revealing a rapidly fading point of light near a faint nebula. Another gamma-ray burst was found in the same way a few months later, and this time the optical spectrum was recorded by the Keck telescope on Hawaii. This told us unambiguously that gamma-ray bursts lie at the very edges of the universe, making them the most energetic phenomenon we know of. Although these findings have solved part of the puzzle, we still do not know what causes gamma-ray bursts. Their formation appears to be related to the deaths of massive stars, and almost certainly requires matter to be flung into space at close to the speed of light. The bursts are so bright that they can be detected out to very great distances, and could eveout to very great distances, and could even hold the record for the most distant known objects. In principle, more sensitive detectors could see gamma-ray bursts from even further away. This could prove to be the only way of observing the early universe, when the first stars and galaxies were forming. (author)

  3. Elemental analysis of human placenta by neutron irradiation and gamma-ray spectrometry (standard, prompt and fast-neutron)

    International Nuclear Information System (INIS)

    Human placental tissue from 100 hospitalized deliveries were analysed for Ag, Al, As, Au, Ba, Br, Ca, Cd, Cl, Co, Cr, Cs, Cu, F, Fe, I, Hg, K, La, Mg, Mn, Mo, Na, Ni, Rb,S, Sb, Sc, Se, Sn, Sr, Ti, V, W and Zn using a combination of pre-chemical separation of sodium with hydrated antimony pentoxide and instrumental neutron activation analysis. Boron and Si values were determined using prompt gamma-ray and fast-neutron techniques respectively. Analysis of NBS-SRM Bovine Liver 1577 and a 'pooled standard' placental tissue for 33 elements showed a good agreement with most coefficients of variation less than or equal to 15%, and recoveries of 91-104%. Symmetrical distributions were obtained for all elemental placental values. Only Cd(-) and Zn(+) showed statistically significant correlations with birth weight, gestational age and placental weight. The influence of cigarette smoking is considered a major factor in producing elevated cadmium levels in the placental tissue of smokers and passive smokers, and hence lower birth weights. (author)

  4. Influence to reject effect on tumor cells by pre-irradiation with low dose-rate gamma-rays

    International Nuclear Information System (INIS)

    Radiation has been supposed to be harmful no matter how low the dose is. We have, however, observed that low dose-rate irradiation increased the tumor cells rejecting ability in mice. The technique we used was TD50 (tumor dose 50) assay. The TD50 value indicates the number of cells required for successful transplantation to a half of injected site in the transplanted animals. We examined the rejective effect on tumor cell in pre-irradiated and non-irradiated mice using of TD50. Pre-irradiated groups were exposed 137Cs ?-rays at 0.4-1.2 mGy/hr. We found that TD50 values in mice irradiated with a total dose of 250 mGy were increased compared to non-irradiated mice. These results suggested that the low dose-rate irradiation increased, under certain conditions, the tumor cell rejecting ability in mice. (author)

  5. Study of uptake and endocytosis of gamma rays-irradiated crotoxin by mice peritoneal macrophages; Avaliacao do mecanismo de captacao e endocitose de crotoxina submetida a acao da radiacao, por macrofagos peritoneais de camundongos

    Energy Technology Data Exchange (ETDEWEB)

    Cardi, Bruno Andrade

    1999-07-01

    The purpose was to investigate the uptake and endocytosis of 2000 Gy {sup 60}Co irradiated crotoxin through mouse peritoneal macrophages, correlating with native one and another non related protein, the ovalbumin. Native (CTXN) or 2000 Gy {sup 60} Co {gamma}-rays (dose rate 540 Gy/hour) irradiated crotoxin (CTXI) or ovalbumin processed of same manner (OVAN - OVAI) were offered to mouse peritoneal macrophages and their uptake was evaluated by immunohistochemistry and quantitative in situ ELISA. The involvement of scavenger receptors (ScvR) was evaluated by using blockers drugs (Probuco-PBC or Dextran Sulfate - SD) or with nonspecific blocking using fetal calf serum (FBS). The morphology and viability of macrophages were preserved during the experiments. CTXI showed irradiation-induced aggregates and formation of oxidative changing were observed on this protein after gamma rays treatment. By immunohistochemistry we could observe heavy stained phagocytic vacuole on macrophages incubated with CTXI, as compared with CTXN. Quantitatively by in situ ELISA, the sema pattern was observed, displaying a 2-fold CTXI incorporation. In presence of PBC or SD we could find a significant decrease of CTXI uptake but not of CTXN. However the CTXN uptake was depressed by FBS, not observed with CTXI. OVA, after gamma rays treatment, underwent a high degradation suffering a potent incorporation and metabolism by macrophages, with a major uptake of OVAI in longer incubation (120 minutes). Gamma rays ({sup 60} Co) produced oxidative changes on CTX molecule, leading to a uptake by ScvR-mice peritoneal macrophages, suggesting that the relation antigen-presenting cells and gamma rays-modified proteins are responsible for the better immune response presented by irradiated antigens. (author)

  6. The methodology study of time accelerated irradiation of elastomers

    Science.gov (United States)

    Ito, Masayuki

    2005-07-01

    The article studied the methods how to shorten the irradiation time by increasing dose rate without changing the relationship between dose versus properties of degraded samples. The samples used were nine kinds of EPDM which have different compounding formula. The different dose of Co-? ray was exposed to the samples. The maximum dose was 2 MGy. The reference condition to be compared with two short time test conditions is irradiation of 0.33 kGy/h at room temperature. Two methods shown below were studied as the time-accelerate irradiation conditions.Irradiation of 4.2 kGy/h in 0.5 MPa oxygen at room temperature. Irradiation of 5.0 kGy/h in air at 70 °C. After irradiation the mechanical properties of samples were measured at room temperature. The changes in 100% modulus suggest that irradiation in 0.5 MPa oxygen increases slightly scission reaction and irradiation at 70 °C increases slightly crosslinking, compared with the results obtained under low dose rate irradiation (the reference condition). The deviation was mostly in ±0.25 for 100% modulus and was ±0.5 for ultimate elongation throughout the all doses, where the value obtained at the reference condition referred to as 1.0. Thus, it was found out that two methods mentioned above are available as time accelerated irradiation conditions.

  7. Gamma ray attenuation measurements

    International Nuclear Information System (INIS)

    The good resolution of a Ge(Li) detector was used to measure gamma ray attenuation coefficients in narrow beam geometry. The effect of multiple scattering on the pulse height distribution of the transmitted gamma rays and on the measured attenuation coefficients was studied and shown to be small up to three mean free paths. Values of attenuation coefficients were determined in the case of lead for 0.662 MeV, 1.116 MeV, 1.17 MeV and 1.33 MeV gamma rays, and in the case of tantalum and molybdenum for 0.662 MeV and 1.116 MeV gamma rays. The experimental values are in fair agreement with the calculated ones. (Auth.)

  8. Detecting onset of chain scission and crosslinking of ?-ray irradiated elastomer surfaces using frictional force microscopy

    Science.gov (United States)

    Banerjee, S.; Sinha, N. K.; Gayathri, N.; Ponraju, D.; Dash, S.; Tyagi, A. K.; Raj, Baldev

    2007-02-01

    We report here that atomic force microscopy (AFM) in frictional force mode can be used to detect the onset of chain scission and crosslinking in polymeric and macromolecular samples upon irradiation. A systematic investigation to detect chain scission and crosslinking of two elastomers, (1) ethylene-propylene-diene monomer rubber and (2) fluorocarbon rubber, upon ?-ray irradiation has been carried out using frictional force microscopy (FFM). From the AFM results we observed that both the elastomers show a systematic smoothening of its surfaces, as the ?-ray dose rate increases. However, the frictional property studied using FFM of the sample surfaces show an initial increase and then a decrease as a function of dose rate. This behaviour of increase in its frictional property has been attributed to the onset of chain scission, and the subsequent decrease in friction has been attributed to the onset of crosslinking of the polymer chains. The evaluated qualitative and semi-quantitative changes observed in the overall frictional property as a function of the ?-ray dose rate for the two elastomers are presented in this paper.

  9. Correlation between radiation-induced defects, and optical properties of pure fused silica-core optical fiber, under gamma-ray irradiation in air at 1273 K

    International Nuclear Information System (INIS)

    Radiation-induced effects on optical properties such as thermoluminescence and optical absorption of pure fused silica-core optical fibers were investigated in situ under gamma-ray irradiation at 0.16 mGy/s and 1273 K in air. The intensities of broad optical transmission peaks below 900 nm decreased due to appearances of non-bridging oxygen hole center (NBOHC), oxygen deficiency centers (ODCs), and optical leakage with increasing annealing time. The intensities of optical absorption and luminescence characteristics peaks at 1390 nm were enhanced by the increment of Si-OH concentration due to the reaction of water vapor or hydrogen with NBOHC, ODCs, and SiO2 glass network. In addition, high resolution-transmission electron microscopy (HR-TEM) showed that SiO2 crystals approximately 10 nm in diameter were formed in the clad and core of the irradiated optical fiber. The crystallization of the SiO2 glass network had greater influence on the optical transmission and luminescence properties.

  10. Effect of gamma-ray irradiation on the size and properties of CdS quantum dots in reverse micelles

    International Nuclear Information System (INIS)

    Cadmium sulfide quantum dots 1.3–5.6 nm in size have been synthesized in sodium bis(2-ethylhexy1)sulfosuccinate (AOT)–water–isooctane micellar solutions with various [H2O]/[AOT] molar ratios (w=2.5, 5.0 or 10). Gamma irradiation method has been used to change the size and optical properties of quantum dots. It has been found that ?-irradiation reduces the size polydispersity of quantum dots in the micellar system and alters their fluorescent properties. Fluorescence intensity is enhanced after ?-irradiation. The average fluorescence lifetime of single quantum dots sized 5.2±0.4 nm increases from 5.14 to 6.39 ns after ?-irradiation at a dose of 7.9 kGy. To the best of our knowledge, this is the first report on fluorescence lifetime of single CdS quantum dots in micellar solution. - Highlights: • Gamma irradiation method has been used successfully to change the size and optical properties of CdS quantum dots synthesized in micellar solutions. • ?-Irradiation reduces the size polydispersity of quantum dots in the micellar system. • Fluorescence intensity of CdS quantum dots is enhanced after ?-irradiation. • Fluorescence lifetime of single CdS quantum dots increases after ?-irradiation

  11. Radiosensitivity, mutation and tetraploid induction in the gamma-ray-irradiated growing shoots in mulberry, Morus alba L

    International Nuclear Information System (INIS)

    The vigorously developing mulberry shoots on the 1 year old grafted trees of the variety Inchinose were separately exposed to 60Co ?-ray of 6KR at 120 R/hr and 7.5 KR at 150 R/hr in early July, early August and early September. After the irradiation, all of the irradiated shoots developed axially buds with malformed narrow leaves, and after that, all plants subjected to the irradiation in September and 30% of the July irradiation group and 40% of the August irradiation group both with higher exposure ceased shoot development. This type of radiation damage was large for the plants with higher exposure as compared with those with lower one, and it was also severe for the plants irradiated in July in comparison with those in August. From the ceasing of shoot development the LD50 value of 150 R/hr irradiation was estimated to be a little more than 7.5 KR. The frequencies of mutation and tetraploid in the grafts produced by the propagation of the axially buds below the leafless portion were high in the grafts with higher exposure than those with lower one, and also the frequencies were high in July irradiation in comparison with August irradiation. It was confirmed that the size of mutation or tetraploid sector was large in the shoots derived from the less advanced axially bud primordia at the time of irradiation than that from the advanced ones. All of tetraploids were the cytochimeras having diploid epidermises over tetraploid internal tissues. (Koses over tetraploid internal tissues. (Kobatake, H.)

  12. The differential role of human macrophage in triggering secondary bystander effects after either gamma-ray or carbon beam irradiation.

    Science.gov (United States)

    Dong, Chen; He, Mingyuan; Tu, Wenzhi; Konishi, Teruaki; Liu, Weili; Xie, Yuexia; Dang, Bingrong; Li, Wenjian; Uchihori, Yukio; Hei, Tom K; Shao, Chunlin

    2015-07-10

    The abscopal effect could be an underlying factor in evaluating prognosis of radiotherapy. This study established an in vitro system to examine whether tumor-generated bystander signals could be transmitted by macrophages to further trigger secondary cellular responses after different irradiations, where human lung cancer NCI-H446 cells were irradiated with either ?-rays or carbon ions and co-cultured with human macrophage U937 cells, then these U937 cells were used as a bystander signal transmitter and co-cultured with human bronchial epithelial cells BEAS-2B. Results showed that U937 cells were only activated by ?-irradiated NCI-H446 cells so that the secondary injuries in BEAS-2B cells under carbon ion irradiation were weaker than ?-rays. Both TNF-? and IL-1? were involved in the ?-irradiation induced secondary bystander effect but only TNF-? contributed to the carbon ion induced response. Further assay disclosed that IL-1? but not TNF-? was largely responsible for the activation of macrophages and the formation of micronucleus in BEAS-2B cells. These data suggest that macrophages could transfer secondary bystander signals and play a key role in the secondary bystander effect of photon irradiation, while carbon ion irradiation has conspicuous advantage due to its reduced secondary injury. PMID:25896631

  13. Degradation of transport critical current of Y123 and Bi(Pb)2223 HTSC ceramics under gamma-ray irradiation

    International Nuclear Information System (INIS)

    The relations of a transport critical current of high-temperature superconductors Bi(Pb)2223 and Y123 from fluence a gamma - quantum Co60 are investigated. It is established, that the reduction Jc for both materials happens in the same interval of dozes of irradiation. It can testify about unified mechanism of radiation damage in Bi(Pb)2223 and Y123 ceramics. The changes of relations of a critical current from an external magnetic field at irradiation a gamma - quantum show, that diamagnetic properties of both materials are less sensitive to irradiation, on a comparison with a critical current

  14. Measurement of characteristic prompt gamma rays emitted from oxygen and carbon in tissue-equivalent samples during proton beam irradiation

    OpenAIRE

    Polf, Jerimy C.; Panthi, Rajesh; Mackin, Dennis S; McCleskey, Matt; Saastamoinen, Antti; Roeder, Brian T; Beddar, Sam

    2013-01-01

    The purpose of this work was to characterize how prompt gamma (PG) emission from tissue changes as a function of carbon and oxygen concentration, and to assess the feasibility of determining elemental concentration in tissues irradiated with proton beams. For this study, four tissue-equivalent water-sucrose samples with differing densities and concentrations of carbon, hydrogen, and oxygen were irradiated with a 48 MeV proton pencil beam. The PG spectrum emitted from each sample was measured ...

  15. Influence of the molecular modifications on the properties of EPDM elastomers under irradiation

    Science.gov (United States)

    Davenas, J.; Stevenson, I.; Celette, N.; Vigier, G.; David, L.

    2003-08-01

    The degradation of the mechanical behaviour of EPDM elastomers used as cable insulation materials has been investigated by mechanical spectroscopy and tensile tests for different formulations: unvulcanised EPDM, vulcanised and stabilised elastomer with an antioxidant. In all cases, ?-irradiation of EPDM under oxygen leads to a reduction of the molecular mobility indicated by the shift of the glass transition relaxation temperature towards higher temperatures. Moreover, the molecular flow occurring above Tg is suppressed after irradiation for the unvulcanised EPDM providing evidence of cross-linking. The competition between cross-linking and chain scissions is shown by the decrease of the storage modulus above the crystallites melting temperature (˜40 °C) at doses larger than 100 kGy. A strong increase of the Young modulus and reduction of the elongation at break of the non-vulcanised EPDM becoming more brittle are shown by stress/strain characterisations performed at 80 °C. At the opposite vulcanised EPDM exhibits higher elongation at break after crystallites melting. This evolution is interpreted by the competition between cross-linking and chain scissions, being hindered by the crystallites at room temperature. The intrinsic irradiation effects can be isolated after crystallite melting. The reduction of the molecular mobility can be explained by a chemi-crystallisation process assisted by chain scissions, leading to a more rigid phase upon irradiation.

  16. Influence of the molecular modifications on the properties of EPDM elastomers under irradiation

    International Nuclear Information System (INIS)

    The degradation of the mechanical behaviour of EPDM elastomers used as cable insulation materials has been investigated by mechanical spectroscopy and tensile tests for different formulations: unvulcanised EPDM, vulcanised and stabilised elastomer with an antioxidant. In all cases, ?-irradiation of EPDM under oxygen leads to a reduction of the molecular mobility indicated by the shift of the glass transition relaxation temperature towards higher temperatures. Moreover, the molecular flow occurring above Tg is suppressed after irradiation for the unvulcanised EPDM providing evidence of cross-linking. The competition between cross-linking and chain scissions is shown by the decrease of the storage modulus above the crystallites melting temperature (?40 deg. C) at doses larger than 100 kGy. A strong increase of the Young modulus and reduction of the elongation at break of the non-vulcanised EPDM becoming more brittle are shown by stress/strain characterisations performed at 80 deg. C. At the opposite vulcanised EPDM exhibits higher elongation at break after crystallites melting. This evolution is interpreted by the competition between cross-linking and chain scissions, being hindered by the crystallites at room temperature. The intrinsic irradiation effects can be isolated after crystallite melting. The reduction of the molecular mobility can be explained by a chemi-crystallisation process assisted by chain scissions, leading to a more rigid phase upon irraleading to a more rigid phase upon irradiation

  17. Radiosensitizing effect of nitric oxide in tumor cells and experimental tumors irradiated with gamma rays and proton beams

    International Nuclear Information System (INIS)

    Nitric oxide (NO) has been reported to be a radiosensitizer of mammalian cells under hypoxic conditions. In a previous study, we demonstrated an enhancement in radiation response induced by NO in mouse tumor cells under aerobic conditions, with an increasing effect as a function of malignancy. The aim of the present study was to evaluate the effect of NO in tumor cells and in experimental tumors irradiated with ? rays and proton beams. Irradiations were performed with a 137Cs ? source and with proton beams generated by the TANDAR accelerator. Tumor cells were treated with the NO donor DETA-NO and the sensitizer enhancement ratio (SER) was calculated using the ? parameter of the survival curve fitted to the linear-quadratic model. Tumor cells irradiated with protons were radio sensitized by DETA-NO only in the more malignant cells irradiated with low LET protons (2.69±0.08 keV/?m). For higher LET protons there were no radiosensitizing effect. For human tumor cells pre-treated with DETA-NO and irradiated with ? rays, a significantly greater effect was demonstrated in the malignant cells (MCF-7) as compared with the near normal cells (HBL-100). Moreover, a significant decrease in tumor growth was demonstrated in mice pre-treated with the NO donor spermine and irradiated with ? rays and low LET protons as compared with mice irradiated without pre-treatment with the NO donor. In conclusion, we demonstrated a differential effect of NO as a radiosensitizer of malignant cells, both with ? rays and low LET protons. This selectivity, coupled to the in vivo inhibition of tumor growth, is of great interest for the potential use of NO releasing agents in radiotherapy. (author)

  18. Effect of gamma-ray irradiation on hybridization between Chamaecyparis obtusa S. et Z. and C. pisifera S. et Z

    International Nuclear Information System (INIS)

    The effect of gamma irradiation on the interspecific hybridization between Chamaecyparis obtusa and C. pisifera was investigated, and F1 seedlings were examined cytologically. Acute gamma irradiation and chronic gamma irradiation given throughout annual growing seasons on male flowers were effective in producing hybrids between these two species. The crossing of C. obtusa x C. pisifera was better than the reverse crossing because the pollen of C. obtusa rapidly loses its fertility, and C. pisifera blooms earlier than C. obtusa. Chronic gamma irradiation of male flowers throughout the annual growing season was slightly effective for producing the hybrids, but that of female flowers was not. Acute gamma irradiation of male flowers at the first to second telophase (300 R) was considered to be desirable for hybrid production. However, it was confirmed by cytological observation that all of the hybrids produced were triploid which had two identical genomes originated from either parent. Therefore, the unreduced male gametophytes or unreduced eggs seem to participate in the formation of the hybrids. It seems difficult to produce diploid hybrids between C. obtusa and C. pisifera. (Kaihara, S.)

  19. Study on the properties of blend rubber prepared with grafted rubber and irradiated rubber by Gamma Rays

    International Nuclear Information System (INIS)

    The blend rubbers were prepared by mixing ?-rays irradiated and monomer grafted rubbers. The monomers, methyl methacrylate (MMA) and styrene were used separately to prepare grafted rubber by exposure to radiation. The physico-chemical properties of the blend rubbers were evaluated. The tensile strength and elongation at break of the blend rubbers decrease whereas modulus at 500% elongation, swelling ratio and permanent set increase with the increased proportion of grafted rubber in the blend. The tear strength of the blend between irradiated and styrene grafted rubbers increases with the increased proportion of grafted rubber but that of the blend of irradiated and MMA grafted rubbers remains almost constant. The blend rubber could be used for special type of application like rubber thread, tube, catheter etc

  20. Measurement of characteristic prompt gamma rays emitted from oxygen and carbon in tissue-equivalent samples during proton beam irradiation.

    Science.gov (United States)

    Polf, Jerimy C; Panthi, Rajesh; Mackin, Dennis S; McCleskey, Matt; Saastamoinen, Antti; Roeder, Brian T; Beddar, Sam

    2013-09-01

    The purpose of this work was to characterize how prompt gamma (PG) emission from tissue changes as a function of carbon and oxygen concentration, and to assess the feasibility of determining elemental concentration in tissues irradiated with proton beams. For this study, four tissue-equivalent water-sucrose samples with differing densities and concentrations of carbon, hydrogen, and oxygen were irradiated with a 48 MeV proton pencil beam. The PG spectrum emitted from each sample was measured using a high-purity germanium detector, and the absolute detection efficiency of the detector, average beam current, and delivered dose distribution were also measured. Changes to the total PG emission from (12)C (4.44 MeV) and (16)O (6.13 MeV) per incident proton and per Gray of absorbed dose were characterized as a function of carbon and oxygen concentration in the sample. The intensity of the 4.44 MeV PG emission per incident proton was found to be nearly constant for all samples regardless of their carbon concentration. However, we found that the 6.13 MeV PG emission increased linearly with the total amount (in grams) of oxygen irradiated in the sample. From the measured PG data, we determined that 1.64 × 10(7) oxygen PGs were emitted per gram of oxygen irradiated per Gray of absorbed dose delivered with a 48 MeV proton beam. These results indicate that the 6.13 MeV PG emission from (16)O is proportional to the concentration of oxygen in tissue irradiated with proton beams, showing that it is possible to determine the concentration of oxygen within tissues irradiated with proton beams by measuring (16)O PG emission. PMID:23920051

  1. The Improvement of Atomita-4 Rice Variety Through Gamma Rays Irradiation of F1 Seeds from Atomita-4/Ir-64 Crossing

    International Nuclear Information System (INIS)

    Atom ita-4 rice variety was crossed with IR-64 variety in the greenhouse at the Center for Application of Isotopes and Radiation-Batan, Pasar jumat in the wet season of 1994/1995. F1 Seeds derived from Atomita-4/IR-64 crossing were irradiated by gamma rays at of 0.2 kGy dose. F1 seeds were grown to obtain F2 M2 seed, and then selection of pedigree were carried out at F2 generation. Six mutants lines were obtained purified and screened on biotypes 1, 2 and 3 brown plant hopper and bacterial leaf blight resistance by IRRI standard screening methods. The six mutant lines were tested for their potential yield at Pusakanegara and then continued tested in yield multi location test at several locations in Indonesia. Results of the screening test to brown plant hopper showed that two mutant lines Obs-1653/PsJ and Obs-1656/PsJ were resistant to biotype 1, biotype 2 and medium resistant to biotype 3. Obs-1653/PsJ and Obs-1656/PsJ also showed resistance to bacterial leaf blight strain 3 and medium resistance to strain 4. Results in the yield multi location test showed that Obs-1653/PsJ and Obs-1656/PsJ have highest yielding potential compared to IR-64 and Memberamo varieties. Those two mutant lines were released as new varieties under the name Merauke and Kahayan in 2001 and 2003 respectively. (author)

  2. Cloning and molecular analysis of GA2ox1 gene mutation generated by gamma-ray 60Co irradiation in mutagenized Tamxoan - TDB06 rice cultivar

    International Nuclear Information System (INIS)

    In the present study, we have used various rice cultivars such as Nipponbare, Tamxoan Hai Hau and mutagenized TDB06 which was obtained from Tamxoan Hai Hau calli irradiated by gamma-ray 60Co with the aim of cloning, sequencing and investigating the molecular mutants of GA2ox1 gene which regulates the height of rice cultivars. Interestingly, we have found that the nucleotide sequence of GA2ox1 gene of mutagenized TDB06 is slightly changed compare to that of original Tamxoan Hai Hau and Nipponbare. The GA2ox1 gene sequence differences of mutagenized TDB06 compared to Tamxoan Hai Hau and Nipponbare are 9 and 2 nucleotides, respectively. We have also shown that the amino acid sequence of GA2ox1 protein is also different among various cultivars in which amino acids corresponding to positions 137 (Alanine), 167 (Threonine), 222 (Valine), 227 (Histidin) of mutagenized TDB06 were replaced with other amino acids Valine, Alanine, Arginine and Lysin, respectively. Nucleotide sequences of GA2ox1 gene isolated from mutagenized TDB06 and Tamxoan Hai Hau cultivars have been registered in Genbank/NCBI with accession numbers EF164903 and EF164904. Based on these initial results, we continuously isolate genes related to dwarf character, construct vectors and do transformation. This strategy can significantly contribute to improve efficiency of rice breeding in Vietnam. (author)

  3. Use of delayed gamma rays for active non-destructive assay of 235U irradiated by pulsed neutron source (plasma focus)

    International Nuclear Information System (INIS)

    A pulsed neutron source based on plasma focus device has been used for active interrogation and assay of 235U by monitoring its delayed high energy ?-rays. The method involves irradiation of fissile material by thermal neutrons obtained after moderation of a burst of neutrons emitted upon fusion of deuterium in plasma focus (PF) device. The delayed gamma rays emitted from the fissile material as a consequence of induced fission were detected by a large volume sodium iodide (NaI(Tl)) detector. The detector is coupled to a data acquisition system of 2k input size with 2k ADC conversion gain. Counting was carried out in pulse height analysis mode for time integrated counts up to 100 s while the temporal profile of delayed gamma has been obtained by counting in multichannel scaling mode with dwell time of 50 ms. To avoid the effect of passive (natural) and active (from surrounding materials) backgrounds, counts have been acquired for gamma energy between 3 and 10 MeV. The lower limit of detection of 235U in the oxide samples with this set-up is estimated to be 14 mg

  4. Standard test method for determining the content of cesium-137 in irradiated nuclear fuels by high-resolution gamma-ray spectral analysis

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method covers the determination of the number of atoms of 137Cs in aqueous solutions of irradiated uranium and plutonium nuclear fuel. When combined with a method for determining the initial number of fissile atoms in the fuel, the results of this analysis allows atom percent fission (burn-up) to be calculated (1). The determination of atom percent fission, uranium and plutonium concentrations, and isotopic abundances are covered in Test Methods E 267 and E 321. 1.2 137Cs is not suitable as a fission monitor for samples that may have lost cesium during reactor operation. For example, a large temperature gradient enhances 137Cs migration from the fuel region to cooler regions such as the radial fuel-clad gap, or, to a lesser extent, towards the axial fuel end. 1.3 A nonuniform 137Cs distribution should alert the analyst to the potential loss of the fission product nuclide. The 137Cs distribution may be ascertained by an axial gamma-ray scan of the fuel element to be assayed. In a mixed-oxide fu...

  5. Use of delayed gamma rays for active non-destructive assay of {sup 235}U irradiated by pulsed neutron source (plasma focus)

    Energy Technology Data Exchange (ETDEWEB)

    Andola, Sanjay; Niranjan, Ram [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kaushik, T.C., E-mail: tckk@barc.gov.in [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Rout, R.K. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kumar, Ashwani; Paranjape, D.B.; Kumar, Pradeep; Tomar, B.S.; Ramakumar, K.L. [Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Gupta, S.C. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-07-01

    A pulsed neutron source based on plasma focus device has been used for active interrogation and assay of {sup 235}U by monitoring its delayed high energy ?-rays. The method involves irradiation of fissile material by thermal neutrons obtained after moderation of a burst of neutrons emitted upon fusion of deuterium in plasma focus (PF) device. The delayed gamma rays emitted from the fissile material as a consequence of induced fission were detected by a large volume sodium iodide (NaI(Tl)) detector. The detector is coupled to a data acquisition system of 2k input size with 2k ADC conversion gain. Counting was carried out in pulse height analysis mode for time integrated counts up to 100 s while the temporal profile of delayed gamma has been obtained by counting in multichannel scaling mode with dwell time of 50 ms. To avoid the effect of passive (natural) and active (from surrounding materials) backgrounds, counts have been acquired for gamma energy between 3 and 10 MeV. The lower limit of detection of {sup 235}U in the oxide samples with this set-up is estimated to be 14 mg.

  6. The early response of pineal N-acetyltransferase activity, melatonin and catecholamine levels in rats irradiated with gamma rays

    International Nuclear Information System (INIS)

    Male Wistar rats adapted to an artificial light-dark regimen were whole-body gamma-irradiated with a dose of 14.35 Gy. Irradiation, sham-irradiation and decapitation 30, 60 and 120 min after the exposure were performed between 2000 h and 0100 h in the darkness. The serotonin N-acetyltransferase activity (NAT), the concentration of melatonin and corticosterone were also determined. Ionizing radiation did not change the activity of NAT, the key enzyme of melatonin synthesis; however, it decreased the concentration of pineal melatonin. The concentration of pineal dopamine and norepinephrine decreased 30 and 120 min after exposure, while the concentration of epinephrine was elevated 30 min after irradiation, though later it was markedly decreased. The serum melatonin level was not changed but an increase in corticosterone level was observed. In the early period after exposure a decrease in pineal melatonin occurred, accompanied by a decrease in pineal catecholamines. On the contrary, in the phase of developed radiation injury the signs of increased melatonin synthesis were observed on days 3 and 4 after the exposure. (author) 6 figs., 25 refs

  7. Influence of Melatonin on The Ultrastructure of Posterior Midgut of Male Ceratitis Capitata (Wied.) Irradiated With Gamma Rays

    International Nuclear Information System (INIS)

    The basic architecture and organization of the posterior midgut epithelial cells in male med flies, Ceratitis capitata (Diptera, Tephtitidae), have been inspected after being subjected to sterilizing dose of gamma radiation (90 Gy). Their midgut cells damages were monitored by means of electron microscope. The treated cells were swollen and have slight vacuolation and increase of vesicles. The ground cytoplasm contained large vacuoles of myelinoid bodies, slight irregularity of few RER, lipid droplets and multi vesicular bodies. Some mitochondria were polymorlyphic owing to swelling of membrane or fusion together to form various shapes. Midgut epithelial cells of insects pre-treated with melatonin prior to gamma irradiation showed approximately normal structures, and preservation could be observed. The combined treatment by irradiation and melatonin could be successfully used to reduce the adverse effects of irradiation and subsequently can be used in the integrated pest management to help in the success of the sterile insect technique against the insects as well as to minimize complications of irradiation on sensitive non-target organs. This has many applications during radiotherapy for patients with cancer

  8. Primary explants of human uroepithelium show an unusual response to low-dose irradiation with cobalt-60 gamma rays

    International Nuclear Information System (INIS)

    Recent results using very low doses of radiation have suggested that there is a hypersensitive region where cultures show an enhanced level of cell killing leading to a non-monotonic survival curve. This effect has been observed at doses below 2 Gy in mammalian systems and at much higher doses in insect cells. In this paper we report observation of the effect in primary human uroepithelial cell cultures. The effect was measured using a postirradiation proliferation assay where irradiated explants of standard size were allowed to proliferate for 14 days after exposure to 60Co? irradiation. By 14 days the majority of cultures derived from explants irradiated with 2-5 Gy showed little evidence of growth inhibition and cell numbers approached or even exceeded those obtained in the controls. There was, however, a significant reduction in cell number and growth rate in all cultures exposed to doses lower than 1 Gy. Oncoprotein and EGFR expression were also measured in these cultures and were significantly increased. Morphological evidence of apoptosis was present in all irradiated cultures at 4 h after exposure, but this persisted for longer periods in cultures exposed to low doses. 18 refs., 2 figs., 4 tabs

  9. Burn-up profiling of PHWR by high resolution gamma-ray spectrometry of irradiated Zr-2.5%Nb pressure tubes

    International Nuclear Information System (INIS)

    'Full text:' Zr-2.5%Nb Pressure tubes, being used in Indian PHWRs from Kakrapar Atomic Power Station, unit 2 (KAPS-2) onwards, are subjected to long term irradiation (around 30 years). The mono-isotopic element niobium with a thermal neutron cross-section of 1.15 barns, generates significant amount of the radionuclide 94GNb, whose half-life is as long as 20,300 years. Of course, 94GNb is also produced by the decay of its short-lived isomer 94mNb (T1/2 = 6.26 min). Hence, the amount of the radionuclide 94GNb produced in the pressure tube is a permanent record of the neutron fluence it is exposed during its residence period in the reactor. The pressure tube from the coolant channel S7 was taken out of the reactor, after a residence time of 8 effective full power years for surveillance. Gamma-ray spectra are obtained on samples of about 20 mg each, taken from 13 positions along the 5100 mm length of the pressure tube using an efficiency calibrated HPGe detector in Compton suppression mode for durations of 1000 to 9000 sec, after a cooling period of 3.3 years. The prominent gamma ray activity in all the samples is from 94GNb (702 and 871 keV) and 60GCo (1173 and 1332 keV). The other radio-nuclides present in these samples include 125Sb, 54Mn, 182Ta, 125mTe, 95Nb and 95Zr. The absolute activities of all these radio-nuclides were detities of all these radio-nuclides were determined from the peak areas of these spectra using the absolute detection efficiency of the detector determined with a standard 152Eu source. The spectral data was used to generate the axial profiles of the activities of the two radionuclides 94GNb and 60GCo for the two gamma ray activities for each of them along the length of the tube, which on normalisation showed good consistency. This profile should represent the average neutron flux seen by the tube, though several fuel bundles stay at each of the 12 locations in the channel for various residence periods adding to the corresponding 8 effective full power years of reactor operation. The profile obtained is compared with that generated by theoretical models. Also this neutron fluence profile is correlated with the burn up profile of the channel computed from the burn up data of all the fuel bundles stayed in the channel in the residence period. These measurements, when performed on the pressure tubes in some more selected channels, would go a long way in experimentally generating the radial and axial power distribution of the core for the relevant residence period. (author)

  10. Gamma Ray Bursts

    Science.gov (United States)

    Gehrels, Neil; Meszaros, Peter

    2012-01-01

    Gamma-ray bursts (GRBs) are bright flashes of gamma-rays coming from the cosmos. They occur roughly once per day ,last typically lOs of seconds and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this review we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglows.

  11. Thermoluminescence, thermoluminescence emission and optical absorption of CsI:Pb2+ crystals irradiated with gamma rays

    International Nuclear Information System (INIS)

    Thermoluminescence, thermoluminescence emission and optical absorption studies have been made in lead doped cesium iodide crystal. Unirradiated crystal gives rise to optical absorption bands at 275, 230, 225 and 213 nm which are identified as the A,B,C,D, bands respectively of the lead impurity. The bands formed on irradiation at 382 nm and 331 nm are attributed to the Pb+ and Pb centres formed on irradiation. The TL glow curves show a peak at 383 K and a shoulder at 423 K. The peak at 383 K has emission at 330, 450 and 550* nm while the shoulder at 423 K has emission at 550 nm only. These peaks are attributed to Pb+ and Pb 0. (author). 15 refs., 5 figs

  12. Effect of spermidine on the survival of saccharomyces cerevisiae cells irradiated with different doses of gamma rays

    International Nuclear Information System (INIS)

    Saccharomyces cerevisiae cells were used to test the radioprotective effect of added spermidine [H3N(CH2)3NH2(CH2)4NH3]3+ as one of the natural polyamines that are essential for cell life. Spermidine plays an important role in suppressing radiation damages at certain concentration (10-5M/L), either via scavenging free radicals or via reducing the frequency of radiation - induced mutations. Spermidine increased noticeably the D10 value at concentration of 10-5 M/L compared with the other two used concentrations of 10-6 and 10-4 M/L. Applying spermidine before irradiation was more effective than applying it after irradiation. (author)

  13. Inverse gamma ray dose rate effect in californium-252 RBE experiment with human T-1 cells irradiated in vitro

    International Nuclear Information System (INIS)

    Metabolically deoxygenated suspensions of human T-1 cells were used to determine the RBE in hypoxia of low dose rate (LDR) Cf-252 radiation compared to LDR gamma radiation. Based upon the initial portion of the survival curves the RBE was 5.0 ± 1.0 for all components of the Cf-252 radiation and 7.1 ± 1.7 for the neutrons alone. An inverse dose rate effect was observed for LDR gamma radiation in which greater cell sensitivity was observed at lower dose rates and longer irradiation periods. It was demonstrated that there was little or no sublethal damage repair or cell progression during LDR at 21 deg C, and the observed decrease in cell survival probability with increasing irradiation time at a given dose was attributable to reoxygenation of the cell suspensions during the course of LDR exposures. (Auth.)

  14. Resveratrol effects on life span and fertility of caenorhabditis elegans subject to 60Co gamma ray irradiation

    International Nuclear Information System (INIS)

    Caennorhabditis elegans was used as experimental model to investigate radiation effect of resveratrol on caenorhabditis elegans irradiated by 60Co ? ray. Treatment with resveratrol can increase average life span and spawning rate, improve the survival rate of eggs, and protect their mitochondrion function of caenorhabditis elegans exposure to 60Co ? ray. The results indicate that resveratrol has radiation protection effects, which might be related to its action on ROS decrease and mitochondrial defend. (authors)

  15. Changes in the microflora of Vienna sausages after irradiation with gamma-rays and storage at 10 deg C

    International Nuclear Information System (INIS)

    The species of microorganisms which can grow on commercial viennas on the storage at 10 deg C were Lactobacillus, Streptococcus and yeasts. When the viennas specially made which did not contain preservatives in it were used for this investigation, growth of microorganisms such as Lactobacillus, Streptococcus, Micrococcus, Bacillus and yeasts were predominant on the storage at 10 deg C, and Pseudomonas and molds some time propagated. When smoked-viennas specially made for the National Project were used for preservation, growth of microorganisms consisted mainly of the species of Lactobacillus, Micrococcus, Acinetobacter, Flavobacterium, Streptococcus, Serratia, Corynebacterium and yeasts. Irradiation of viennas at 300 and 500 krad reduced the aforementioned flora to the Lactobacillus, Streptococcus, Acinetobacter and yeasts. The number of microorganisms on the viennas packed with nitrogen gas was not increased for 3 to 7 days by means of 300 krad irradiation, and extended the storage-life 2 to 3 times. When irradiated with a dose of 500 krad, the number of microorganisms was not increased for 9 to 14 days on the storage at 10 deg C. (author)

  16. Some aspects of the behavior at different ages of Ceratitis capitata (Wiedemann, 1824) (Diptera-Tephritidae) irradiated with gamma rays

    International Nuclear Information System (INIS)

    The present work was carried out in the laboratory of the Entomology Section of the Nuclear Energy for Agriculture Center (CENA) in Piracicaba, Sao Paulo state, Brazil, to determine the effects different gamma radiation doses on the reproductive potential of males and the flight behavior of Ceratitis capitata (Wied.). For all the treatments with gamma radiation a Cobalt-60 source type Gamma beam-650 was used, with activity of approximately 13,410 x 10B Bq. (4,967 Ci.), and the dose rate of 2.000 Gy per hour. The doses used were 80 Gy, 100 Gy and 120 Gy. The three doses employed affected more the longevity of males than the females and the number of spermatozoid found lower in the irradiated insects compared with the control, with no significant differences between doses. The insects irradiated with 80 Gy showed activity similar to the control population until four days after emergence: afterwards they were more active than the unirradiated. The gamma irradiation diminished the take-off ability of the insects. (author). 59 refs., 9 figs., 9 tabs

  17. Identification of gamma ray irradiated and unirradiated foodstuffs by electron spin resonance (ESR) and thermoluminescence (TL) techniques

    International Nuclear Information System (INIS)

    In this study, the identification of irradiated food samples containing cellulose, bone and sugar was done by Electron Spin Resonance (ESR) technique. The change of ESR signal intensities using in this identification process with radiation dose and storage time was followed. The radiation induced ESR signal intensities of sugar, green tea, sage tea, lentil and shrimp samples increased with increasing dose. It was not observed any significant change on the ESR signal intensities of sugar samples with storage time at ambient temperature. But the radiation induced ESR signal intensities for the other samples decreased with time at ambient temperature. In this work, for red lentil samples, the changes of ESR spectral parameters of heat-induced free radical ESR signals with heating temperatures were also investigated. It has investigated also that whether a possible radiation treatment could be identified of red pepper samples sold in Turkish markets using Thermoluminescence method which have been adopted or proposed TS EN 1788:2007 Standard (Foodstuffs-Detection of Irradiated Food From Which Silicate Minerals Can be Isolated-Method by Thermoluminescence). Firstly, the glow curve of silicate minerals isolated from the red pepper samples has been recorded (TL1), and after a subsequent exposure of the already measured minerals to a defined radiation gamma dose (1kGy) has been recorded as a second glow curve (TL2). It has been concluded that the red pepper samples have not been irradiated evaluating the glow curve shapes and the TL glow ratios (TL1/TL2).

  18. Approach to the resistance of exportation tebo worms when irradiated with gamma ray through a quarantine treatment

    International Nuclear Information System (INIS)

    The tebo worms or butterworms (Chilecomadia moorei) are widely used in Chile in fishing, and so are in the international markets although there are some countries, that use these species, to a less extent for preparing food reptiles. Some foreign countries requirements demand, from the exporters, to carry out quarantine treatments related to the sterilization by ionizing energy, however customers need to make sure about their products safety and that is why it is compulsory to establish limits in connection with worms' irradiation resistance. The irradiation effect on a worms sample using doses of 0.3; 0.45; 0.6 and 0.9 kGy was studied macroscopically, after 1 hour, and then 30, 60 and 90 days after the treatment. One of the equipment utilized had a Cobalt 60 source, where as the other one had Cesium 137 irradiators, with a dose rate of 42.7 Gy minute (min)-1 and 37.1 Gy min-1, respectively. The results concluded that tebo worms can resist more than 3 times the doses suggested by the meta countries without reducing the population drastically, nevertheless it is required to increase the number of worms to be analyzed in order to validate the findings. (author)

  19. Evaluation of components of X-ray irradiated 7-valent pneumococcal conjugate vaccine and pneumococcal vaccine polyvalent and X-ray and gamma-ray irradiated acellular pertussis component of DTaP vaccine products

    Energy Technology Data Exchange (ETDEWEB)

    May, J.C. E-mail: may@cber.fda.gov; Rey, L. E-mail: louis.rey@bluewin.ch; Lee, C.-J.; Arciniega, Juan

    2004-10-01

    Samples of pneumococcal vaccine polyvalent, 7-valent pneumococcal conjugate vaccine, and two different diphtheria and tetanus toxoids and acellular pertussis vaccines adsorbed were irradiated with X-rays and/or gamma-rays (Co-60). Mouse IgG and IgM antibody responses (ELISA) for types 9V, 14, 18C, and 19F pneumococcal polysaccharides and conjugates indicated that the polysaccharides were more tolerant of the radiation than the conjugates. The mouse antibody response for the detoxified pertussis toxin (PT) antigen, filamentous hemagglutinin antigen (FHA), pertactin (PRN), and fimbriae types 2 and 3 (FIM) antigens for the appropriate vaccine type indicated that the antibody response was not significantly changed in the 25 kGy X-ray irradiated vaccines frozen in liquid nitrogen compared to the control vaccine.

  20. Evaluation of components of X-ray irradiated 7-valent pneumococcal conjugate vaccine and pneumococcal vaccine polyvalent and X-ray and gamma-ray irradiated acellular pertussis component of DTaP vaccine products

    International Nuclear Information System (INIS)

    Samples of pneumococcal vaccine polyvalent, 7-valent pneumococcal conjugate vaccine, and two different diphtheria and tetanus toxoids and acellular pertussis vaccines adsorbed were irradiated with X-rays and/or gamma-rays (Co-60). Mouse IgG and IgM antibody responses (ELISA) for types 9V, 14, 18C, and 19F pneumococcal polysaccharides and conjugates indicated that the polysaccharides were more tolerant of the radiation than the conjugates. The mouse antibody response for the detoxified pertussis toxin (PT) antigen, filamentous hemagglutinin antigen (FHA), pertactin (PRN), and fimbriae types 2 and 3 (FIM) antigens for the appropriate vaccine type indicated that the antibody response was not significantly changed in the 25 kGy X-ray irradiated vaccines frozen in liquid nitrogen compared to the control vaccine

  1. The effects of ?-ray irradiation on the properties of polyolefin elastomer composite material

    International Nuclear Information System (INIS)

    The Polyolefin elastomer/Magnesium hydroxide (POE/MH) composite material was irradiated using 60Co ?- ray to study the radiation effects on tensile properties, flame retardancy and thermal stability. The gel content result showed that the gel content of the POE reached 49.5% at doses 150 kGy. For POE/MH in irradiation doses 75 kGy, the gel content increased by 57.9% compared with non-irradiated samples. Tensile test showed that the tensile strength of the POE irradiated at doses 75 kGy increased by 63.3% compared with the non-irradiated samples. The tensile strength of the POE/MH irradiated at doses 125 kGy, increased by 85.5% from the non-irradiated POE/MH. Thermal mechanical performance test showed that the softening point of the composite with flame retardant content of 120 shares was 194.0? for sample irradiated at doses 125 kGy, while that was 131.9? for the sample without irradiation. In flame experiment, the limiting oxygen index (LOI) of the composite material with MH content of 120 shares is 32 after irradiating at doses 125 kGy. And meanwhile, the irradiation could effectively improved the melt dropping property of the flame-retardant material in the process of combustion. The droplet is gradually reduced with the radiation dose increased. The above data indicated that seemly irradiation could effectively enhance the tensile properties, flame retardancy and thermal stability of the flame-retardant composite material. (authors)

  2. Reaction mechanisms in ? irradiated high surface silica-elastomer systems

    International Nuclear Information System (INIS)

    Complete text of publication follows. In this work the mechanism of the ?-ray induced vulcanization of the binary systems consisting of styrene butadiene rubber (SBR; 30% stryrene, 25% vinyl units) and high surface silica (160-1000 m2/g) are investigated by matrix EPR spectroscopy, ATR-FTIR and by measuring the crosslinking kinetics. The experiments have dealt with pristine silica, silica modified by radiation grafting of polybutadiene olygomers (SiO2/PB) and the SBR compounds containing 30-40% of pristine or modified silica. The irradiation under vacuum of the pristine silica gives rise to thermally unstable species which decay at very low temperature, below 180 K. When the SBR/silica compounds are irradiated, in addition to the SBR radicals, also SBR chain radicals is greatly enhanced when using silica coated with polybutadiene olygomers bearing high (25-45%) vinyl double bond content. The rationale of such observation is that the species generated within the bulk of the silica particles migrate to the surface where are scavenged by the vinyl double bonds of the absorbed chains. It is thus assessed that the direct radiolysis of silica plays an active role in the radiation vulcanization process by promoting the formation of silica-rubber chemical links which are of key importance in the reinforcement mechanism. The crosslinking kinetics were found to be coherent with the above observation showing that the crosslinks yield vs dose ratios increase in the order: pure SBR 2 2(PB).

  3. Study of the ionization of alkane-electron scavenger reactant mixtures irradiated by 60Co gamma rays

    International Nuclear Information System (INIS)

    This study deals with ionization of alkane-electron scavenger reactant mixtures, irradiated by 60Co ?-rays. It is shown that the extrapolated free-ion yields (extrapolated yield method) decrease with the reactant concentration. On the basis of ONSAGER model and theoretical treatment of MOZUMDER, the cross sections of epithermal electron attachment in hexane, cyclohexane, 2,2-dimethylbutane, cyclopentane, 2,2,4-trimethylpentane for CCl4, C7F14, C6H5Br, C6H5Cl, C6F14, (C6H5)2 are determined. A comparison between gas-phase and liquid-phase cross sections is established

  4. Thermal properties of irradiated ethylene-propylene copolymers

    International Nuclear Information System (INIS)

    Samples of crude ethylene-propylene copolymers, of the elastomer types EPDM and EPR, were prepared by solvent removal from polymer solutions. The EPDM contained 3.5% ethylidene norbornene. Samples of the elastomers were irradiated with gamma rays to different absorbed doses in the range 50-1000kGy. Specific heat capacity measurements were made over the temperature range 330-430K for each absorbed dose. Oxygen uptake determinations were also made. The observations and the difference in behaviour between the elastomers are explained in terms of free radical recombination, crosslinking and scission. (UK)

  5. The Effect Of SEA On Long Tail Monkeys (Macaca Fascicularis) Lymphocyte Culture Gamma Ray-Irradiated In Vitro

    International Nuclear Information System (INIS)

    Staphylococus enteroxine (SEA) is one of toxins produced by the bacterium Staphylococus aureus. In the culture, SEA has proven as a potent stimulator of lymphocytes in man event at fg/ml concentrations. This research studied the effect of SEA compared to Phytohaemagglutinine (PHA) on the peripheral blood lymphocytes culture of the long-tail monkeys. About 5 ml blood was collected from 5 monkeys and irradiated using Gamma Cell-220 P3TIR with doses of 0 (control); 1.0; 2.0; 3.0 and 4.0 Gy. The blood samples were cultured in the appropriate growth medium based on standard procedure and added with 1.0 ml (0.5 mug/ml) SEA or 0.15 ml PHA. The cultures were then incubated for 96 hours and prepared the slides. The results showed that on the unirradiated peripheral blood lymphocytes of long-tail monkeys the mitotic indices obtained using PHA and SEA are relatively similar. On the irradiated lymphocytes with doses of 1-3 Gy, the mitotic indices using SEA are relatively higher than that of PHA. Dose responses of dicentric, ring and acentric fragment of both PHA and SEA are relatively the same

  6. Chemical changes in the chloroform-paraffin-dye system irradiated with 60Co gamma-rays, 2

    International Nuclear Information System (INIS)

    Studies have been carried out on the amount of hydrogen chloride formed by the radiolysis of chloroform in a solid paraffin-chloroform-Methyl Yellow system, and the color changes from yellow to red and absorption energy observed. The amount of hydrogen chloride formed and the intensity of the red color were determined with a pH meter, a spectrophotometer, and a color/ color-difference meter. It was found that the color-difference meter had the most excellent spectral response and sensitivity for measurement of the irradiated sample, and that the color-difference, ?E, obtained by reflectometry increased proportionally with the increase in the radiation dose throughout a region of 100 -- 5000 R. When a solid sample composed of 1.0 kg paraffin (m.p. 62 -- 640C), 0.74 kg chloroform and 3.4 x 10-3 mol Methyl Yellow was subjected to 1000 R irradiation at 200C, 2.5 x 1014 molecules of hydrogen chloride were formed in 1.0 g of the solid sample with the absorption energy of 5.9 x 1016 eV, 3.2 x 1016 eV of which contributed to chloroform as the absorption energy. (author)

  7. Mechanical properties and failure surfaces of gamma-ray irradiated systems based on thermoplastic 1,2 polybutadiene

    International Nuclear Information System (INIS)

    The effect of 60Co gamma-radiation on the mechanical properties of clay filled and unfilled 1,2 polybutadiene (1,2 PBD) and 1,2 PBD-natural rubber (NR) blends has been investigated. In the case of blends the effects on blend ratio and filler have been studied with reference to absorbed radiation dose varying from 0.1 to 100 Mrad at room temperature. Radiation was found to transform the flexible samples to brittle and rigid materials especially at high dose levels. The stress-strain behaviour, tensile strength, elongation, tension set and crosslink density were found to be markedly affected at dose levels of 10 Mrad and above. On irradiation 1,2 PBD was found to undergo predominantly crosslinking while the blends exhibited both crosslinking and chain scission due to the presence of NR. The tensile fracture surfaces of the irradiated samples were examined by scanning electron microscope (SEM) in order to gain insight into the mechanism of failure. (author)

  8. Mechanical properties and failure surfaces of gamma-ray irradiated systems based on thermoplastic 1,2 polybutadiene

    Science.gov (United States)

    Bhagawan, S. S.; Kuriakose, B.; De, S. K.

    The effect of 60Co gamma-radiation on the mechanical properties of clay filled and unfilled 1,2 polybutadiene (1,2 PBD) and 1,2 PBD-natural rubber (NR) blends has been investigated. In the case of blends the effects on blend ratio and filler have been studied with reference to absorbed radiation dose varying from 0.1 to 100 Mrad at room temperature. Radiation was found to transform the flexible samples to brittle and rigid materials especially at high dose levels. The stress-strain behaviour, tensile strength, elongation, tension set and crosslink density were found to be markedly affected at dose levels of 10 Mrad and above. On irradiation 1,2 PBD was found to undergo predominantly crosslinking while the blends exhibited both crosslinking and chain scission due to the presence of NR. The tensile fracture surfaces of the irradiated samples were examined by scanning electron microscope (SEM) in order to gain insight into the mechanism of failure.

  9. Morphological variation in the 7th generation soybean mutant lines irradiated by gamma ray under greenhouse conditions

    Directory of Open Access Journals (Sweden)

    M. Younessi Hamzehkhanlu

    2012-06-01

    Full Text Available Genetic diversity is the base of plant breeding. Hence, 33 M7 soybean mutant lines, which were evolved by ? ray from cultivar L17 irradiated with doses of 150, 200 and 250 Gray (absorbed dose, with L17 cultivar and two commercial cultivars (Clark and Williams were evaluated in view of some morphological traits (number of leaves/plant, pods/plant, seeds/pod, seeds/plant, 100-seed weight, dry weight of aerial parts, dry weight of roots, plant yield, harvest index, nodules/root and dry weight of nodules under completely randomized design with three replications in greenhouse of Agricultural, Medical and Industrial Research School, Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran, Karaj, Iran. All traits in the studied mutant lines, except number of seeds per pod, showed a significant difference at ?=1% and ?=5% in comparison with L17 and commercial cultivars. Mutant line number 13 (M13 was recognized as the top line in view of the studied traits. Seed yield per plant showed the highest correlation (0.886 with harvest index (P<0.01. Cluster analysis of the studied traits along with Ward method resulted in separation of the lines into four independent groups. It can be inferred from the results that irradiation did induce significant genetic variability with regard to majority of the studied traits, such as number of nodules per plant and harvest index.

  10. A study on the effect of 60Co gamma ray irradiation on the abrasion of dental polymethylmethacrylate, (2)

    International Nuclear Information System (INIS)

    This study is intended to improve scratch resistance of acrylic (hereafter called P.M.M.A.) molded products by first coating acrylic resin with well compatible cross-linking plastics of various kinds and, during the hardening stage, exposing them to radioactive irradiation to build up a hard coat to improve scratch resistance on the surface. From these studies, the following conclusions were reached. By the barrel test which considered scratches and abrasion caused by impacts against relatively hard objects as seen in biting resembling to the wet conditions in oral cavity, fairly well scratch resistance and abrasion resistance were obtained. These treatments give more effects to scratch resistance and abrasion resistance in the brushing conditions rather than in the striking against hard objects. For all specimen, scratch resistance and abrasion resistance in wet conditions can be expected to be three times greater than they are in dry conditions. (author)

  11. Nanoparticles of Al2O3:Cr as a sensitive thermoluminescent material for high exposures of gamma rays irradiations

    International Nuclear Information System (INIS)

    Aluminum Oxide (Al2O3) doped with proper activators is a highly sensitive phosphor commonly used for radiation dosimetry using thermoluminescence (TL) technique. Nanoparticles of this material activated with Chromium (Cr) have been synthesized using the propellant chemical combustion technique and studied for their TL response. They were characterized by X-ray diffraction and scanning electron microscope. The synthesized material has spherical nanoparticles with grain size around 25 nm. These nanoparticles were exposed to heavy doses from ?-rays of 137Cs. The TL glow curves show a prominent peak at around 474 K. This peak is found to be sensitive for high exposures of ?-rays and has linear response in the range of 100 Gy-20 kGy without showing saturation. This remarkable result suggests that Al2O3:Cr nanoparticles might be used for the dosimetry of food and seed irradiations.

  12. Effect of gamma-ray irradiated natural herbal extracts on NF-kB activation in HMC-1 cells

    International Nuclear Information System (INIS)

    Recently, studies have documented various health benefits of some natural herbal extracts (NHE) such as Houttuynia cordata (H), Centella asiatica (C), Plantago asiatica (P), Morus alba L. (M), and Ulmus davidiana (U). The aim of the present study was to demonstrate the radiation effect on NF-kB activation of the NHE in the human mast cell line (HMC-1). The HMC-1 cells were stimulated with phorbol 12-myristate 13-acetate (PMA) plus A23187. Both non-and irradiated NHE also significantly inhibited the PMA plus A23187-induced nuclear factor NF-kB activation and also suppressed the expression of activation of NF-kB. These results indicated that the NHE exerted a regulatory effect on inflammatory reactions mediated by mast cells

  13. Effect of gamma-ray irradiated natural herbal extracts on NF-kB activation in HMC-1 cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Soo; Lim, Youn Mook; Gwon, Hui Jeong; Choi, Bo Ram; Nho, Young Chang [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2009-12-15

    Recently, studies have documented various health benefits of some natural herbal extracts (NHE) such as Houttuynia cordata (H), Centella asiatica (C), Plantago asiatica (P), Morus alba L. (M), and Ulmus davidiana (U). The aim of the present study was to demonstrate the radiation effect on NF-kB activation of the NHE in the human mast cell line (HMC-1). The HMC-1 cells were stimulated with phorbol 12-myristate 13-acetate (PMA) plus A23187. Both non-and irradiated NHE also significantly inhibited the PMA plus A23187-induced nuclear factor NF-kB activation and also suppressed the expression of activation of NF-kB. These results indicated that the NHE exerted a regulatory effect on inflammatory reactions mediated by mast cells.

  14. Dependence of free ion yield on electrical field strength in some liquid alkanes irradiated by 60 Co gamma rays

    International Nuclear Information System (INIS)

    The dependence of the free ion yield, Gsub(fi), on electrical field strength was determined in four liquid alkanes: n-hexane, 2,2-dimethyl butane, 2,2,4-trimethylpentane and 2,2-dimethylpropane irradiated by 60Co ? rays at several temperatures. The sample purity effect on Gsub(fi) values has also been investigated. The Onsager theory applied to the experimental Gsub(fi) = f(E) curves allowed to estimate the distribution function F(r) of the initial separation distances r of ions in these alkanes. A modified exponential distribution seems to be the most suitable. The Jaffe theory to 2,2-dimethylpropane results permitted to determine the total ion yield value, Gsub(tot), for this liquid: Gsub(tot) = 4.3 +- 0.3

  15. Formation of radical cations and dose response of alpha-terthiophene-cellulose triacetate films irradiated by electrons and gamma rays

    CERN Document Server

    Emmi, S S; Ceroni, P; D'Angelantonio, M; Lavalle, M; Fuochi, P G; Kovács, A

    2002-01-01

    The radiation-induced UV-vis spectrum of alpha-terthiophene radical cation in solid is reported. The radical cation initiates an oligomerization in the CTA matrix producing permanently coloured conjugated polarons. The specific net absorbance at 465 nm is linearly related with dose up to 2x10 sup sup 6 sup sup G y, for electrons and gamma irradiation. The decrease of the UV typical absorption (355 nm) and of four IR bands of alpha-terthiophene is linear with dose, as well. Although sensitivity is influenced by dose rate, it turned out that a linear relationship holds between sensitivity and log dose rate, in the range from 2 to 10 sup sup 5 Gy, min. These findings suggest a potential application of the system for dosimetric purposes over a wide range of dose and dose rate.

  16. Chemist's gamma-ray table

    International Nuclear Information System (INIS)

    An edited listing of gamma-ray information has been prepared. Prominent gamma rays originating from nuclides with half lives long enough to be seen in radiochemical experiments are included. Information is ordered by nuclide in one section and by energy in a second section. This shorter listing facilitates identification of nuclides responsible for gamma rays observed in experiments

  17. Detection and confirmation of two novel mitochondrial DNA deletions in human lymphoblastoid cell line irradiated by 60Co gamma rays

    International Nuclear Information System (INIS)

    Objective: To screen the radiation induced mitochondtial DNA (mtDNA) deletion and confirm it. Methods: Long-range PCR with two pairs of primers, which could amplify the whole human mitochondrial genome, was used to analyze the lymphoblastoid cell line before and after exposed to 10 Gy 60Co ?-rays. The limited condition PCR was used to certify the possible mtDNA deletion shown by long-range PCR. The PCR products were purified, cloned, sequenced and the sequence results were BLASTed. Results: The predicted bands of mtDNA were observed on the control cell lines, and the possible mtDNA deletions were also detected on the irradiated cell lines. The deletions were certified by the limited condition PCR. The sequence BLAST results of the cloned PCR products showed that there were two kinds of deletions, 7455 bp deletion (nt475-7929 in heavy strand) and 9225 bp deletion (nt7714-369 in heavy strand), which were both results from 8 bp direct repeats. Further bioinformatics analysis showed that the two deletions were novel deletions. Conclusions: Ionizing radiation could induce the 7455 bp and 9225 bp deletions in human lymphocytes. (authors)

  18. Poly(acrylic acid)/polyethylene glycol hygrogel prepared by using gamma-ray irradiation for mucosa adhesion

    Science.gov (United States)

    Nho, Young-Chang; Park, Jong-Seok; Shin, Jung-Woong; Lim, Youn-Mook; Jeong, Sung-In; Shin, Young-Min; Gwon, Hui-Jeong; Khil, Myung-Seob; Lee, Deok-Won; Ahn, Sung-Jun

    2015-01-01

    A buccal delivery system provides a much milder environment for drug delivery compared to an oral delivery which presents a hostile environment for drugs, especially proteins and polypeptides, owing to acid hydrolysis. Local delivery in an oral cavity has particular applications in the treatment of toothaches, periodontal disease, and bacterial infections. Poly(acrylic acid) (PAA)-based hydrogels prepared using a chemical initiator have been attempted for a mucoadhesive system owing to their flexibility and excellent bioadhesion. In this experiment, PAA and polyethylene glycol (PEG) were selected to prepare using a radiation process a bioadhesive hydrogel for adhesion to mucosal surfaces. PAA and PEG were dissolved in purified water to prepare a homogeneous PAA/PEG solution, and the solution was then irradiated using an electron beam at dose up to 70 kGy to make the hydrogels. Their physical properties, such as gel percent, swelling percent, and adhesive strength to mucosal surfaces, were investigated. In this experiment, various amounts of PEG were incorporated into the PAA to enhance the mucoadhesive property of the hydrogels. The effect of the molecular weight of PEG on the mucoadhesion was also examined.

  19. Transformation of egg-white glass into partially crystallized glass induced by heat treatment and gamma-ray irradiation

    International Nuclear Information System (INIS)

    Egg-white gel is easily transformed into transparent 'glass' by drying at ambient temperature, e.g., at 25degC for 140 min. The optical transmittance is increased from 2 to 25% accompanied with a decrease in the weight by more than 70%. Broad and intense IR absorption peaks observed at 3288-3308 and 1653-1657 cm-1 were respectively assigned to ?(NH) and ??(C=0) stretching modes in the amido (RCONH-) groups, and the ?(NH) bending mode was observed at 1521-1546 cm-1. Differential thermal analysis (DTA) study showed a distinct endothermic peak due to the glass transition, and the peak position was located at 36, 42, 58 and 69degC when the heating rates were 2, 5, 10 and 20degC min-1, respectively. Heat treatment of egg-white glass at 60degC or ?-ray irradiation resulted in partial crystallization, and the XRD patterns showed a few diffraction peaks superimposed on the halo peak due to the glassy phase. (author)

  20. Age and sex dependence in tumorigenesis in mice by continuous low-dose-rate gamma-ray whole-body irradiation

    International Nuclear Information System (INIS)

    We investigated the dependency of sex and age in mice in the induction of neoplasms by gamma-rays from cesium-137 at a low dose rate of 0.375Gy/22h/day. Thymic lymphomas occurred significantly at the same incidence in both sexes, and more frequently when younger mice were exposed to radiation. Strain C57BL/6J mice were divided into 8 groups, which were whole-body irradiated with a total dose of 39Gy for 105 days each. The exposure was begun at 28 days of age (male:AM1, female:AF1), and then stepwise increasing the starting age by 105 days, i.e., from 133 days (AM2 and AF2), from 238 days (AM3 and AF3), and from 343 days (AM4 and AF4), respectively. Unirradiated mice served as control (UM and UF). The incidence of thymic lymphomas was about 60 % in AM1, AM2, AF1 and AF2, 40 % in AM3 and AF3 and 20 % in AF4 and AF4, demonstrating no sex dependency, but a distinct age dependency, for lymphomogenesis. It was proven that mice showed a tendency to become less susceptible to radiation induced thymic lymphoma with increasing age. Concomitantly, life-shortening also was caused, and the greater the degree of life-shortening was, the younger the mice were the start of exposure. Life-shortening was attributed to thymic lymphoma, and hemorrhage and infectious diseases due to the depletion of bone marrow cells. (author)

  1. Cellular response to low Gamma-ray doses

    International Nuclear Information System (INIS)

    Lymphocytes, obtained from healthy donors, were exposed to a low strength gamma-ray field to determine heat shock protein expression in function of radiation dose. Protein identification was carried out using mAb raised against Hsp70 and Hsc70.Hsp70 protein was detected after lymphocyte irradiation. In all cases, an increasing trend of relative amounts of Hsp70 in function to irradiation time was observed. After 1.25 c Gy gamma-ray dose, lymphocytes expressed Hsp70 protein, indicating a threshold response to gamma rays. (Author)

  2. Gamma ray beam transmutation

    International Nuclear Information System (INIS)

    We have proposed a new approach to nuclear transmutation by a gamma ray beam of Compton scattered laser photon. We obtained 20 MeV gamma ray in this way to obtain transmutation rates with the giant resonance of 197Au and 129Iodine. The rate of the transmutation agreed with the theoretical calculation. Experiments on energy spectrum of positron, electron and neutron from targets were performed for the energy balance and design of the system scheme. The reaction rate was about 1.5?4% for appropriate photon energies and neutron production rate was up to 4% in the measurements. We had stored laser photon more than 5000 times in a small cavity which implied for a significant improvement of system efficiency. Using these technologies, we have designed an actual transmutation system for 129Iodine which has a 16 million year's activity. In my presentation, I will address the properties of this scheme, experiments results and transmutation system for iodine transmutation

  3. Gamma-Ray Bursts

    OpenAIRE

    Fynbo, Johan P. U.; Malesani, Daniele; Jakobsson, P. Xe Ll Eds C. Kouveliotou; Fynbo; Malesani, Johan P. U.; Daniele; Jakobsson; Kouveliotou, P. Xe Ll Eds C.; Wijers, R. A. M. J.; Woosley, S. E.

    2006-01-01

    Gamma-ray bursts are the most luminous explosions in the Universe. They appear connected to supernova remnants from massive stars or the merger of their remnants, and their brightness makes them temporarily detectable out to the larges distances yet explored in the Universe. After pioneering breakthroughs from space and ground experiments, their study is entering a new phase with observations from recently launched satellites, as well as the prospect of detections or limits ...

  4. Gamma-Ray Bursts

    OpenAIRE

    Gehrels, Neil; Meszaros, Peter

    2014-01-01

    Gamma-ray bursts are the most luminous explosions in the Universe. They appear connected to supernova remnants from massive stars or the merger of their remnants, and their brightness makes them temporarily detectable out to the larges distances yet explored in the Universe. After pioneering breakthroughs from space and ground experiments, their study is entering a new phase with observations from recently launched satellites, as well as the prospect of detections or limits ...

  5. Gamma-Ray Localization of Terrestrial Gamma-Ray Flashes

    International Nuclear Information System (INIS)

    Terrestrial gamma-ray flashes (TGFs) are very short bursts of high-energy photons and electrons originating in Earth's atmosphere. We present here a localization study of TGFs carried out at gamma-ray energies above 20 MeV based on an innovative event selection method. We use the AGILE satellite Silicon Tracker data that for the first time have been correlated with TGFs detected by the AGILE Mini-Calorimeter. We detect 8 TGFs with gamma-ray photons of energies above 20 MeV localized by the AGILE gamma-ray imager with an accuracy of ?5-10 deg. at 50 MeV. Remarkably, all TGF-associated gamma rays are compatible with a terrestrial production site closer to the subsatellite point than 400 km. Considering that our gamma rays reach the AGILE satellite at 540 km altitude with limited scattering or attenuation, our measurements provide the first precise direct localization of TGFs from space.

  6. Surface treatment of poly(ethylene terephthalate) by gamma-ray induced graft copolymerization of methyl acrylate and its toughening effect on poly(ethylene terephthalate)/elastomer blend

    International Nuclear Information System (INIS)

    To improve the compatibility between ethylene-methyl acrylate-glycidyl methacrylate random terpolymer (E-MA-GMA) elastomer and poly(ethylene terephthalate) (PET), thereby enhance the toughening effect of E-MA-GMA on PET, ?-radiation-induced graft copolymerization technique was used to graft methyl acrylate (MA) monomer onto PET. The produced PET-g-PMA copolymer can be used as a self-compatibilizer in PET/E-MA-GMA blend since the copolymer contains the same segments, respectively, with PET and E-MA-GMA. The impact strength of PET/E-MA-GMA blend increased nearly by 30% in the presence of less than 0.1 wt% PET-g-PMA compared with that of the neat PET/elastomer blend, without loss of the tensile strength of the blends. This work proposed a potential application of radiation-induced grafting copolymerization technique on the in-situ compatibilization of PET/elastomer blends so as to improve the integral mechanical properties of PET based engineering plastic. - Highlights: • PMA was grafted onto PET resins by ?-ray radiation-induced copolymerization. • The obtained PET-g-PMA can improve the compatibility between PET and E-MA-GMA. • A small amount of PET-g-PMA can enhance the impact strength of PET/E-MA-GMA blend

  7. Experiment on iodine transmutation by laser Compton scattering gamma ray

    International Nuclear Information System (INIS)

    A laser Compton scattering gamma-ray based nuclear transmutation is proposed to reduce the hazards of long-lived activity nuclear waste. In accordance with this proposal, a laser Compton scattering gamma-ray facility has been built on NewSUABARU storage ring. The facility provides 17.6 MeV gamma-ray photons, which is applicable to the nuclear transmutation research. In order to investigate the reaction rate of Iodine material, the 23Na127I target is adopted for the irradiation experiment. The results show that the experimental data is close to the simulation result

  8. An Elementary Treatment of Gamma-Ray Heating and Gamma-Ray Dosage in Inhomogeneous Reactors

    International Nuclear Information System (INIS)

    An analysis is made of the heat produced by the absorption of gamma rays in a sample placed into a reactor. It is clearly shown that enormous local (space) variations in gamma flux exist in current reactors. An application to the Hanford reactors is treated in some detail. Although the estimates obtained may be good to but a factor of two, it is clearly shown that in most cases the major portion of the heating is due to (n, ?) reactions within the sample itself, and in some cases to the gamma rays generated in liners and cans, and not from the gamma rays generated in fission, nor from the moderator. Some implications of these results are discussed, among the most important being their application to radiation chemistry in reactors. Several mathematical results for absorption and generation of gamma rays in various bodies which should be useful in estimating dosage rates for samples irradiated in reactors are given (Appendix II). A method for making the calculations for an arbitrary absorption law are given (Appendix III). This method may be used with the true absorption law for gamma rays or even for the calculation of the absorption of the energy of particles possessing a range law of absorption, e.g., ?-rays or protons.

  9. High energy gamma ray source

    International Nuclear Information System (INIS)

    A method is introduced which is used to produce discrete gamma rays in 5-10 MeV region by means of a?105n/s Am-Be neutron source through the radiation capture process. High energy monochromatic gamma rays with low level backgound are produced utilizing resonance scattering on Pb of gamma rays from the Fe (n, ?) reaction induced by the reactor thermal neutrons. The device is very simple and can conveniently be used for the energy calibration and relative efficiency determination of various gamma rays detectors such as Ge(Li), HpGe, NaI(Tl), BGO, etc

  10. Iodine transmutation through laser compton scattering gamma rays

    International Nuclear Information System (INIS)

    Research on laser Compton scattering gamma-ray-based nuclear transmutation has been carried out to identify a method of reducing the hazards of long-lifetime radioactivity of nuclear waste. To study the photonuclear reaction experimentally, a laser Compton scattering gamma-ray facility was built on a storage ring at NewSUBARU and ?17 MeV gamma-ray photons were produced. An investigation on the reaction rate of radioactive iodine waste was carried out. Based on the characteristics of laser Compton scattering gamma rays, a cylindrical target was adopted for the irradiation experiment. The radioactivity of the irradiated target was measured and the transmutation reaction rate was deduced. Experimental results were close to simulation findings. (author)

  11. Annealing effect on critical temperature and resistivity of (Bi, Pb)[sub 2]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub y] superconductor irradiated by Co-60 gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Makarenko, L.F.; Gurinovich, V.A.; Kononyuk, I.F. (Academy of Sciences of Belarus, Minsk (Belarus))

    1992-12-01

    It was found that annealing at 150-200[sup o]C results in increase of resistivity and drop of critical temperature of superconducting (Bi, Pb)[sub 2]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub y] ceramics irradiated by Co-60 gamma-rays up to doses of 2 x 10[sup 9]R. These parameters recovered afterwards upon annealing at temperatures 300-350[sup o]C. The correlation between the recovery temperatures of irradiated and pre-heated at 100[sup o]C samples was established. It is suggested that the annealing effects are connected to changes in Bi-O twin layer properties due to gamma-irradiation enhancement of gas exchange processes. (author).

  12. Delayed gamma rays

    International Nuclear Information System (INIS)

    Delayed gamma ray radiation is that component of initial nuclear weapon radiation emitted within the first 60 seconds following initiation by products of fission and of neutron activation that are parts of the debris of the nuclear explosion. The debris initially resides within the fireball, a luminous sphere of hot gases generated by the interaction with the air of X rays radiated from the hot debris within a millionth of a second after initiation. The fireball also defines the edge of a region of very low density air created by the expansion of the very hot gases within. The high pressure region created at the edge of this density well forms the shock wave that breaks away from the fireball and travels outward, superimposed on the ambient air. The net effect of these perturbations is to decrease the amount of air on a line from the source to a target, thereby enhancing the transmission of delayed radiation over that which would occur in unperturbed air. This effect is often referred to as hydrodynamic enhancement. The density well is buoyant and begins to rise within a fraction of a second of its creation. Its momentum is augmented by returning shock wave, now reflected off the ground. The rise of the fireball, which includes the radiation source, causes the distance between source and target to increase, thereby causing the radiation transmission to decrease once the expansion of the fireball has slowed or stopped. As the fireball rises the outer surface cools and ireball rises the outer surface cools and is subject to drag forces from the surrounding atmosphere. The drag causes the spherical fireball to become a toroidal cloud of condensed gases, containing the weapon debris. Throughout this process, the weapon debris, including the fission products, are in motion relative to the fireball. First, the debris are propelled toward the top of the fireball with an initial impulse provided by the reflected shock. Eventually the debris pierce the top of the rising fireball and flow down the side, with most becoming incorporated in the torus or in the cloud skirt below the torus. These effects become less pronounced as the scaled burst height increases, where the scaled burst height is defined to be the burst height divided by the yield to the one-third power (HOB/y1/3). This complex system, consisting of a radioactive, hence time-varying, source of gamma rays and similarly time-varying geometry, in which the amount of air between source and target is changing even as the source rises from its original location, must be modeled in some detail to describe properly the intensity of the delayed radiation component. The motive for doing so is that the delayed gamma radiation produces on the order of half the gamma-ray dose at Hiroshima and Nagasaki. Three technical areas must be addressed in the modeling process. They are: 1) the fission product gamma-ray source, 2) gamma-ray transport, and 3) nuclear-weapon hydrodynamics. Data required for modeling the processes of interest in these areas have been acquired through laboratory and field measurements. However, these data are by no means complete. Here follows a discussion of such modeling as it affects the prediction of A-bomb survivor dose as computed using the 1986 Dosimetry System for Japanese A-bomb survivors (DS86)

  13. RELATIVE HTP VALUES AND HTRS OF TLD-100 AND TLD-700 AFTER IRRADIATION IN MIXED FIELD OF ALPHA AND GAMMA RAYS

    International Nuclear Information System (INIS)

    The nuclear track etching technique is used to measure different doses of alpha rays. Recently, some experimental data indicated that TL could be used as tool for gamma and alpha dose determination using single TL-detector. In this study, the short overview of the use of LiF-based TL detectors in mixed radiation field dosimetry was presented. In the experimental part, TL main dosimetry peak and high temperature peak (HTP) for TLD-100 and TLD-700 detectors were investigated for 137Cs gamma rays and alpha of 5 MeV. The results shows that it is possible to determine separately gamma and alpha dose components with a single detector due to different sensitivities of TL to alpha in comparison to gamma rays

  14. Wear properties of nano-Al2O3/UHMWPE composites irradiated by gamma ray against a CoCrMo alloy

    International Nuclear Information System (INIS)

    Nano-Al2O3/ultra-high molecular weight polyethylene (UHMWPE) composites were prepared by hot pressing and then radiated by a gamma ray in doses of 120 kGy, 250 kGy and 500 kGy. The hardness of the composites was tested. The friction and wear properties against a CoCrMo alloy were also tested on a knee simulator under physiological saline solution lubrication. The morphologies of worn surfaces were examined under an optical microscope. The structure of the sample was analyzed by IR and XRD tests. The results showed that the wear rate of UHMWPE decreased when filled with a proper amount of nano-Al2O3, and with an increment of the radiation dose of gamma rays. It was found that filling nano-Al2O3 into UHMWPE can inhibit the effect of oxidation during the radiation procedure

  15. Experimental investigations into the effects of irradiation with neutron and gamma rays on the immune system, as demonstrated at the model of immunity of Salmonella typhimurium on the mouse

    International Nuclear Information System (INIS)

    Mice were irradiated with neutron and gamma rays (with a dose of 200 rad respectively 300 rad). Either 24 hours before or after the irradiation the mice were vaccinated and revaccinated with a Salmonella typhimurium vaccine. By ELISA, IHA and BTZD-test specific antibodies against Salmonella typhimurium could be found. The 200 rad irradiated animals had a lower increase in the formation of antibodies compared with mice not irradiated, if the irradiation was applied before the immunisation. On the 300 rad irradiated animals a reduction of the formation of the antibodies could be observed, too. The antibody titres, however, were higher and an earlier increase of the number of the antibodies was found in comparison with the 200 rad irradiated animals. A second antigene application after 7 days and an irradiation after the first respectively the second immunisation gave no noticeable proof of immune suppression. In our tests it was found out, that for the definition of the antibody titres of the sera the ELISA and the IHA had been more sensitive than the BTZD-test. (orig./MG)

  16. Gamma Ray Astronomy with Muons

    CERN Document Server

    Halzen, Francis; Yodh, G B

    1997-01-01

    Although gamma ray showers are muon-poor, they still produce a number of muons sufficient to make the sources observed by GeV and TeV telescopes observable also in muons. For sources with hard gamma ray spectra there is a relative `enhancement' of muons from gamma ray primaries as compared to that from nucleon primaries. All shower gamma rays above the photoproduction threshold contribute to the number of muons $N_\\mu$, which is thus proportional to the primary gamma ray energy. With gamma ray energy 50 times higher than the muon energy and a probability of muon production by the gammas of about 1\\%, muon detectors can match the detection efficiency of a GeV satellite detector if their effective area is larger by $10^4$. The muons must have enough energy for sufficiently accurate reconstruction of their direction for doing astronomy. These conditions are satisfied by relatively shallow neutrino detectors such as AMANDA and Lake Baikal and by gamma ray detectors like MILAGRO. TeV muons from gamma ray primaries...

  17. Cosmic gamma rays from quasars

    International Nuclear Information System (INIS)

    The diffuse gamma radiation consists of the galactic and extragalactic components. The latter component is of special interest on account of its cosmological significance. Following the method recently proposed to estimate the gamma ray flux from galaxy clusters, and the detection of gamma rays from the quasars 3C273, the data base of the SAS II satellite was used to estimate the contribution from quasars to the extragalactic gamma ray flux. It is shown that quasars as a whole are significant gamma ray contributors, the average gamma ray flux per quasar in the energy range 35 MeV to 100 Mev being (1.3 + or - 0.9) x .00001 cm(-2)s(-1)sr(-1)

  18. Gamma Ray Bursts - Observations

    Science.gov (United States)

    Gehrels, N.; Cannizzo, J. K.

    2010-01-01

    We are in an exciting period of discovery for gamma-ray bursts. The Swift observatory is detecting 100 bursts per year, providing arcsecond localizations and sensitive observations of the prompt and afterglow emission. The Fermi observatory is observing 250 bursts per year with its medium-energy GRB instrument and about 10 bursts per year with its high-energy LAT instrument. In addition, rapid-response telescopes on the ground are providing new capabilities to study optical emission during the prompt phase and spectral signatures of the host galaxies. The combined data set is enabling great advances in our understanding of GRBs including afterglow physics, short burst origin, and high energy emission.

  19. Gamma ray prospecting

    International Nuclear Information System (INIS)

    Means for distinguishing full energy absorption peaks received across an energy band from Compton background energy comprises: (a) means for receiving a gamma ray energy spectrum; (b) means for determining the peak energy level within an energy band of the spectrum, and for integrating the energy within the band, (c) means for determining a statistical value of the Compton background gamma radiation across the photopeak region of the band from the energy level at the edges of the band, and for integrating the background radiation within the band, (d) means for subtracting the integrated statistical value of Compton background energy from the integrated peak energy, and (e) means for providing an output signal representative of the difference of the integrated peak energy level and the integrated statistical value within the band, to provide an indication of the presence of radiation emissive mineral at a particular location

  20. Gamma-Ray Pulsar Revolution

    Science.gov (United States)

    Caraveo, Patrizia A.

    2014-08-01

    Isolated neutron stars (INSs) were the first sources identified in the field of high-energy gamma-ray astronomy. In the 1970s, only two sources had been identified, the Crab and Vela pulsars. However, although few in number, these objects were crucial in establishing the very concept of a gamma-ray source. Moreover, they opened up significant discovery space in both the theoretical and phenomenological fronts. The need to explain the copious gamma-ray emission of these pulsars led to breakthrough developments in understanding the structure and physics of neutron star (NS) magnetospheres. In parallel, the 20-year-long chase to understand the nature of Geminga unveiled the existence of a radio-quiet, gamma-ray-emitting INS, adding a new dimension to the INS family. We are living through an extraordinary time of discovery. The current generation of gamma-ray detectors has vastly increased the population of known gamma-ray-emitting NSs. The 100 mark was crossed in 2011, and we are now over 150. The gamma-ray-emitting NS population exhibits roughly equal numbers of radio-loud and radio-quiet young INSs, plus an astonishing, and unexpected, group of isolated and binary millisecond pulsars (MSPs). The number of MSPs is growing so rapidly that they are on their way to becoming the most numerous members of the family of gamma-ray-emitting NSs. Even as these findings have set the stage for a revolution in our understanding of gamma-ray-emitting NSs, long-term monitoring of the gamma-ray sky has revealed evidence of flux variability in the Crab Nebula as well as in the pulsed emission from PSR J2021+4026, challenging a four-decades-old, constant-emission paradigm. Now we know that both pulsars and their nebulae can, indeed, display variable emission.

  1. Estimating. gamma. -rays dose using computer

    Energy Technology Data Exchange (ETDEWEB)

    Al-Rawi, A.M.; Muslih, R.M.; Al-Harithy, R.S. (Baghdad Univ. (Iraq). Coll. of Education for Women)

    1990-01-01

    When gum arabic is exposed to {gamma}-rays, a change in its reflection and absorption ability for the different wave lengths is obtained. This change is used for estimating the absorbed {gamma}-rays directly. In the present work we are not concerned with the type of components that are chemically formed as emphasis will only be put on the physical changes. The physical state is taken as a potential chemical change since a molecular damage is accumulated as a result of the dose absorbed. The fortran IV data General (Nova 3) designed for estimating colour measurements was connected to a spectrophotometer that enables measuring the changes in both absorbing and reflecting or even diffusing of light through irradiated materials. (author).

  2. Biodegradation polyurethane derived from vegetable oil irradiated with gamma rays 25 kGy and 100 kGy; Biodegradacao de poliuretano derivado de oleo vegetal irradiado com raios gama 25 kGy e 100 kGy

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Antonia M. dos, E-mail: amsantos@rc.unesp.br [Universidade Estadual Paulista - Unesp, Rio Claro, SP (Brazil); Claro Neto, Salvador [Universidade de Sao Paulo - USP, Campus de Sao Carlos, SP (Brazil); Azevedo, Elaine C. de [Universidade Federal do Parana, Campus de Curitiba, PR (Brazil)

    2011-07-01

    The environment requires polymers that can be degraded by the action of microorganisms. In this work was studied the biodegradation of polyurethane samples derived from vegetable oil (castor oil), which were irradiated with gamma rays 25 kGy and 100 kGy compared with the same polyurethane without being irradiated. Biodegradation of polyurethane was carried out in culture medium containing the fungus Aspergillus niger by 146 days and the result was evaluated using the technique of thermogravimetric analysis, where there was a change of behavior of the curves TGA / DTG occurred indicating that chemical modifications of molecules present in the structure of the polymer chain, thus confirming that the material has undergone the action of microorganisms. (author)

  3. Planetary gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    The chemical composition of a planet can be inferred from the gamma rays escaping from its surface and can be used to study its origin and evolution. The measured intensities of certain gamma rays of specific energies can be used to determine the abundances of a number of elements. The major sources of these gamma-ray lines are the decay of natural radionuclides, reactions induced by energetic galactic-cosmic-ray particles, capture of low energy neutrons, and solar-proton-induced radioactivities. The fluxes of the more intense gamma-ray lines emitted from 30 elements were calculated using current nuclear data and existing models. The source strengths for neutron-capture reactions were modified from those previously used. The fluxes emitted from a surface of average lunar composition are reported for 288 gamma-ray lines. These theoretical fluxes have been used elsewhere to convert the data from the Apollo gamma-ray spectrometers to elemental abundances and can be used with results from future missions to map the concentrations of a number of elements over a planet's surface. Detection sensitivities for these elements are examined and applications of gamma-ray spectroscopy for future orbiters to Mars and other solar-system objects are discussed

  4. Gamma rays at airplane altitudes

    International Nuclear Information System (INIS)

    An examination of the gamma ray flux above 1 TeV in the atmosphere is needed to better understand the anomalous showers from point sources. Suggestions are made for future experiments on board airplanes

  5. Isotopic measurement of encapsuled PWR fuel pells by delayed gamma rays counting

    International Nuclear Information System (INIS)

    The fuel pin is irradiated with a thermal neutron flux, the induced fissions are proportional to the quantity of 235U and measured by delayed gamma ray counting. A 252Cf neutron source is used and the gamma rays are counted by three scintillation counters. Owing to a collimator the PM see only one pellet at each time: the efficacity of the collimator is inhanced by not counting the gamma rays above a choice level

  6. Gamma Ray Bursts and CETI

    OpenAIRE

    Smith Jr, Frank D.

    1993-01-01

    Gamma ray burst sources are isotropically distributed. They could be located at distances $\\sim 1000$ AU. (Katz \\cite{JK92}) GRB signals have many narrow peaks that are unresolved at the millisecond time resolution of existing observations. \\cite{JK87} CETI could use stars as gravitational lenses for interstellar gamma ray laser beam communication. Much better time resolution of GRB signals could rule out (or confirm?) the speculative hypothesis that GRB = CETI.

  7. Laboratory gamma-ray pulsar

    OpenAIRE

    Gruzinov, Andrei

    2014-01-01

    The mechanism by which gamma-ray pulsars shine might be reproducible in a laboratory. This claim is supported by three observations: (i) properly focusing a few PW optical laser gives an electromagnetic field in the so-called Aristotelian regime, when a test electron is radiation-overdamped; (ii) the Goldreich-Julian number density of this electromagnetic field (the number density of elementary charges needed for a nearly full conversion of optical power into gamma-rays) is ...

  8. Gamma rays from 103In

    International Nuclear Information System (INIS)

    In the past ten years efforts in using heavy ions for producing nuclear track membranes have been increasing. One of the good candidates is the heavy ion 103In. In the present work this ion was produced in the 50Cr (56Fe, 2 np) 103In reaction and it was separated and its gamma rays were studied on-line. Comparisons were made with previous studies. Good agreements were obtained. Also 14 new gamma rays were identified for the first time

  9. Swift: Gamma-Ray Bursts

    Science.gov (United States)

    In the late 1960s, scientists accidentally discovered gamma-ray bursts, intense flashes of energy that typically last no more than a few seconds or minutes. For decades after the discovery of these powerful bursts, they remained one of the greatest mysteries in astronomy. This video segment discusses the Swift satellite mission, launched in 2004 to investigate gamma-ray bursts, and presents some theories as to their origins. The segment is four minutes fourteen seconds in length.

  10. Multiwavelength Astronomy: Gamma Ray Science

    Science.gov (United States)

    Dieter Hartmann, a high-energy physicist, presents a story-based lesson on the science of Gamma-Ray astronomy. The lesson focuses on gamma-ray bursts; examining their sources, types, and links to the origin and evolution of the Universe. The story-based format of the lesson also provides insights into the nature of science. Students answer questions based on the reading guide. A list of supplemental websites is also included.

  11. Catalogue of gamma rays from radionuclides

    International Nuclear Information System (INIS)

    A catalogue of almost 11000 gamma rays is presented. The gamma rays are sorted by energy. In addition to the gamma-ray intensity per 100 decays of the parent, the decay half-life and associated gamma rays are given. All data are from a computer processing of a recent ENSDF file. (author)

  12. Short gamma ray bursts: formation and offsets

    OpenAIRE

    Boylan, C.; Li, Y.; Fan, X. L.; Heng, I. S.

    2014-01-01

    Short gamma ray bursts have been observed a variety of galaxies types with varying angular offsets from the centre of their host galaxies. To investigate the properties of short gamma ray burst offsets, a sample of short gamma ray bursts with host galaxies has been gathered. Two formation channels proposed to explain the observed offsets of short gamma ray bursts from their host galaxies are discussed. The classification of short gamma ray bursts into these formation channel...

  13. Human Lymphocytes Response to Low Gamma-ray Doses

    Science.gov (United States)

    Vega-Carrillo, Héctor René; Manzanares-Acuña, Eduardo; Bañuelos-Valenzuela, Rómulo

    2002-08-01

    Radiation and non-radiation workers lymphocytes were exposed to a low strength gamma-ray field to determine heat shock protein expression in function of radiation dose. Protein identification was carried out using mAb raised against Hsp25, Hsp60, Hsp70 and Hsp90; from these, only Hsp70 protein was detected before and after lymphocyte irradiation. In all cases, an increasing trend of relative amounts of Hsp70 in function to irradiation time was observed. After 70.5 uGy gamma-ray dose, radiation worker's lymphocytes expressed more Hsp70 protein, than non radiation workers' lymphocytes, indicating a larger tolerance to gamma rays (gammatolerance), due to an adaptation process developed by his labor condition.

  14. Human lymphocytes response to low gamma-ray doses

    International Nuclear Information System (INIS)

    Radiation and non-radiation workers lymphocytes were exposed to a low strength gamma-ray field to determine heat shock protein expression in function of radiation dose. Protein identification was carried out using mAb raised against Hsp25, Hsp60, Hsp70 and Hsp90; from these, only Hsp70 protein was detected before and after lymphocyte irradiation. In all cases, an increasing trend of relative amounts of Hsp70 in function to irradiation time was observed. After 70.5 ?Gy gamma-ray dose, radiation worker's lymphocytes expressed more Hsp70 protein, than non radiation workers' lymphocytes, indicating a larger tolerance to gamma rays (gammatolerance), due to an adaptation process developed by his labor condition

  15. Response of human lymphocytes to low gamma ray doses

    International Nuclear Information System (INIS)

    Radiation and non-radiation workers lymphocytes were exposed to a low strength gamma-ray field to determine heat shock protein expression in function of radiation dose. Protein identification was carried out using mAb raised against Hsp25, Hsp60, Hsp70 and Hsp90; from these, only Hsp70 protein was detected before and after lymphocyte irradiation. In all cases, an increasing trend of relative amounts of Hsp70 in function to irradiation time was observed. After 70.5 mGy gamma-ray dose, radiation worker's lymphocytes expressed more Hsp70 protein, than non-radiation workers' lymphocytes, indicating a larger tolerance to gamma rays (gamma tolerance), due to an adaptation process developed by their labor condition (Au)

  16. A neutron capture gamma-ray facility

    International Nuclear Information System (INIS)

    A neutron capture gamma-ray facility was constructed for prompt gamma-ray spectrometry, and its characteristics were measured. In the facility, a neutron beam is extracted from the H-6 horizontal experimental hole of Japan Research Reactor No.3, JAERI, and a target outside the reactor is irradiated by the beam. Thermal neutron flux at the target position was 8.0 x 107 n/cm2.s and the cadmium ratio (Au) was 21. Characteristics of a Ge gamma-ray spectrometer using a 7 in. diameter x 8 in. length guard NaI (Tl) detector were measured for 3 modes, single, Compton (escape) suppressed and pair, with neutron capture gamma-rays from nitrogen, chromium etc. Characteristics were: (1) in single spectrometer, full-energy peak efficiency 2.3 x 10-5 (1 MeV), 4.6 x 10-6 (5 MeV) and 1.25 x 10-6 (10 MeV); (2) in Compton (escape) suppressed spectrometer, Compton suppression factor 3.5 (1-2 MeV), 5.1 (3-5 MeV) and 5.5 (6-8 MeV), and escape suppression factor 2.57 +- 0.2 (single) and 8.34 +- 1.2 (double); (3) in pair spectrometer, detection efficiency 4.5 x 10-7 (3 MeV), 6.5 x 10-7 (4 MeV), 7.1 x 10-7 (5 MeV) and 7.3 x 10-7 (5.5-10 MeV). Lower detection limits in determination of boron, cadmium and gadolinium by Compton suppressed spectrometry of prompt gamma-rays were evaluated on the basis of the experimental data. The limits under the conditions of 2 g aqueous solution, standard error 10% and counting time 1000 s were 9.0 ?g for B, 12.3 ?g for Cd and 2.9 ?g for Gd. (author)

  17. The Gamma-ray Sky with Fermi

    Science.gov (United States)

    Thompson, David

    2012-01-01

    Gamma rays reveal extreme, nonthermal conditions in the Universe. The Fermi Gamma-ray Space Telescope has been exploring the gamma-ray sky for more than four years, enabling a search for powerful transients like gamma-ray bursts, novae, solar flares, and flaring active galactic nuclei, as well as long-term studies including pulsars, binary systems, supernova remnants, and searches for predicted sources of gamma rays such as dark matter annihilation. Some results include a stringent limit on Lorentz invariance derived from a gamma-ray burst, unexpected gamma-ray variability from the Crab Nebula, a huge gamma-ray structure associated with the center of our galaxy, surprising behavior from some gamma-ray binary systems, and a possible constraint on some WIMP models for dark matter.

  18. Study of stability of humic acids from soil and peat irradiated by gamma rays; Estudo da estabilidade de acidos humicos extraidos de solo e turfa, frente a radiacao ionizante gama

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Wilson Tadeu Lopes da

    1995-07-01

    Humic acids samples (one deriving from a sedimentary soil and other from a peat), in aqueous media, were irradiated with gamma rays, in doses of 10, 50 and 100 kGy, in order to understand their chemical behavior after the irradiation. The material, before and after irradiation, was analyzed by Elemental Analysis, Functional Groups (carboxylic acids and phenols), UV/Vis Spectroscopy (E{sub 4}/E{sub 6} ratio), IR spectroscopy, CO{sub 2} content and Gel permeation Chromatography (GPC) ). The Elemental Analysis showed the humic acid derived from a peat had a most percentage quantity of Carbon and Hydrogen than the material from a sedimentary soil. From the UV/Vis Spectroscopy, it was observed a decrease of E{sub 4}/E{sub 6} ratio with an increase of the applied dose. The data from GPC are in agreement with this. The results showed that the molecular weight of the material increased by exposing it to a larger radiolitical dose. The peat material was less affected by the gamma radiation than the soil material. The carboxylic groups were responsible by radiochemical behavior of the material. (author)

  19. Gamma rays for Ephestia Kuehniella control

    International Nuclear Information System (INIS)

    Trials were undertaken to establish gamma irradiation action on the various developmental stages of Ephestia Kuehniella. It was found that its eggs perished 100% when irradiated with a dose of 6 krad. Mortality of young larvae irradiated with gamma ray dose of 4-22 krad accounted for 23.91-43.64% during the first 10 days, and for 53.9-95% after 50 days. Irradiation with 20-22 krad intensity resulted in 100% mortality 60 days post irradiation. In the case of adult larvae, 8.8-40.57% were killed 10 days post irradiation and 53.98-100% - after 50 days. Some larvae could survive for 90 days post 8-12 krad irradiation. A dose of 20 krad required 70 days to produce 100% mortality and 22 krad - 50 days. Pupae mortality ranged from 28.4 to 30.72%, depending on the dose but their moths lived only 2 days and could not be fertilized. The inference is that gamma irradiation may be used to control Ephestia Kuehniella

  20. Gamma rays for Ephestia Kuehniella control

    Energy Technology Data Exchange (ETDEWEB)

    Assad, Zh.; Shikrenov, D.

    1983-01-01

    Trials were undertaken to establish gamma irradiation action on the various developmental stages of Ephestia Kuehniella. It was found that its eggs perished 100% when irradiated with a dose of 6 krad. Mortality of young larvae irradiated with gamma ray dose of 4-22 krad accounted for 23.91-43.64% during the first 10 days, and for 53.9-95% after 50 days. Irradiation with 20-22 krad intensity resulted in 100% mortality 60 days post irradiation. In the case of adult larvae, 8.8-40.57% were killed 10 days post irradiation and 53.98-100% - after 50 days. Some larvae could survive for 90 days post 8-12 krad irradiation. A dose of 20 krad required 70 days to produce 100% mortality and 22 krad - 50 days. Pupae mortality ranged from 28.4 to 30.72%, depending on the dose but their moths lived only 2 days and could not be fertilized. The inference is that gamma irradiation may be used to control Ephestia Kuehniella.

  1. Cosmic gamma-ray bursts

    International Nuclear Information System (INIS)

    All aspects of cosmic gamma-ray bursts are reviewed. First, instrumentation and experimental technique are briefly covered. Then the observable burst properties are described, and empirical classification schemes are offered. Searches for coinciding bursts at other frequencies are enumerated. The observed spatial distribution of the burst sources is given, as well as various theoretical interpretations. A section is devoted to the unusual gamma-ray burst of March 5, 1979; its features are compared to more typical events and analyzed for insights into burst origins. Theoretical models for gamma-ray bursts are considered in general, and then examined in more detail under the categories of extragalactic models, accretion onto compact objects, thermonuclear explosions, flare models, and exotic models. (orig.)

  2. Zeptosecond $\\gamma$-ray pulses

    CERN Document Server

    Klaiber, Michael; Keitel, Christoph H

    2007-01-01

    High-order harmonic generation (HHG) in the relativistic regime is employed to obtain zeptosecond pulses of $\\gamma$-rays. The harmonics are generated from atomic systems in counterpropagating strong attosecond laser pulse trains of linear polarization. In this setup recollisions of the ionized electrons can be achieved in the highly relativistic regime via a reversal of the commonly deteriorating drift and without instability of the electron dynamics such as in a standing laser wave. As a result, coherent attosecond $\\gamma$-rays in the 10 MeV energy range as well as coherent zeptosecond $\\gamma$-ray pulses of MeV photon energy for time-resolved nuclear spectroscopy become feasible.

  3. Terrestrial gamma-ray flashes

    International Nuclear Information System (INIS)

    Lightning and thunderstorm systems in general have been recently recognized as powerful particle accelerators, capable of producing electrons, positrons, gamma-rays and neutrons with energies as high as several tens of MeV. In fact, these natural systems turn out to be the highest energy and most efficient natural particle accelerators on Earth. Terrestrial Gamma-ray Flashes (TGFs) are millisecond long, very intense bursts of gamma-rays and are one of the most intriguing manifestation of these natural accelerators. Only three currently operative missions are capable of detecting TGFs from space: the RHESSI, Fermi and AGILE satellites. In this paper we review the characteristics of TGFs, including energy spectrum, timing structure, beam geometry and correlation with lightning, and the basic principles of the associated production models. Then we focus on the recent AGILE discoveries concerning the high energy extension of the TGF spectrum up to 100 MeV, which is difficult to reconcile with current theoretical models

  4. Laboratory gamma-ray pulsar

    CERN Document Server

    Gruzinov, Andrei

    2014-01-01

    The mechanism by which gamma-ray pulsars shine might be reproducible in a laboratory. This claim is supported by three observations: (i) properly focusing a few PW optical laser gives an electromagnetic field in the so-called Aristotelian regime, when a test electron is radiation-overdamped; (ii) the Goldreich-Julian number density of this electromagnetic field (the number density of elementary charges needed for a nearly full conversion of optical power into gamma-rays) is of order the electron number density in a solid; (iii) above about $50$PW, the external source of electrons is not needed -- charges will be created by a pair production avalanche.

  5. Gamma-ray Imaging Methods

    Energy Technology Data Exchange (ETDEWEB)

    Vetter, K; Mihailescu, L; Nelson, K; Valentine, J; Wright, D

    2006-10-05

    In this document we discuss specific implementations for gamma-ray imaging instruments including the principle of operation and describe systems which have been built and demonstrated as well as systems currently under development. There are several fundamentally different technologies each with specific operational requirements and performance trade offs. We provide an overview of the different gamma-ray imaging techniques and briefly discuss challenges and limitations associated with each modality (in the appendix we give detailed descriptions of specific implementations for many of these technologies). In Section 3 we summarize the performance and operational aspects in tabular form as an aid for comparing technologies and mapping technologies to potential applications.

  6. Activation of wine bentonite with gamma rays

    International Nuclear Information System (INIS)

    The action of gamma rays on wine bentonite as well as influence of its adsorption and technologic qualities on the composition and stability of wines against protein darkening and precipitation has been studied. The experiments were carried out with wine bentonite produced in the firm Bentonite and irradiated with doses of 0.4, 0.6, 0.8 and 1.0 MR. White and red wines have been treated with irradiated bentonite under laboratory conditions at 1.0 g/dm3. All samples are treated at the same conditions. The flocculation rate of the sediment was determined visually. Samples have been taken 24 h later from the cleared wine layers. The following parameters have been determined: clarification, filtration rate, phenolic compounds, calcium, colour intensity, total extracted substances, etc. The volume of the sediment has been determined also. The control samples have been taken from the same unirradiated wines. The results showed better and faster clarification in on the third, the 20th and the 24th hours with using of gamma-irradiated at doses 0.8 and 1.0 MR. The sediment was the most compact and its volume - the smallest compared to the samples treated with bentonite irradiated with doses of 0.6 and 0.4 MR. This ensures a faster clarification and better filtration of treated wines. The bentonite activated with doses of 0.8 and 1.0 MR adsorbs the phenolic compounds and the complex protein-phenolic molecules better. In the same time it adsorbs less extracted substancme time it adsorbs less extracted substances compared to untreated bentonite and so preserves all organoleptic properties of wine. The irradiated bentonite adsorbs less the monomers of anthocyan compounds which ensures brighter natural colour of wine. The gamma-rays activation consolidates calcium in the crystal lattice of bentonite particles and in this way eliminates the formation of crystal precipitates

  7. Gamma ray assisted fabrication of fluorescent oligographene nanoribbons

    International Nuclear Information System (INIS)

    Graphical abstract: Facile low cost method for production of oligographene nanoribbons is presented. Highlights: ? Gamma ray assisted fabrication of oligographene nanoribbons. ? Facile, large scale and low cost method of graphene nanoribbon fabrication. ? Produced nanoribbons are fluorescent in the blue region of visible spectrum. -- Abstract: In this paper, facile low cost method for production of oligographene nanoribbons is presented. Nanoribbons are produced by gamma ray assisted cutting of oligographene dispersed in cyclopentanone. Width and height of the smallest nanoribbons are 30 and 1 nm, respectively. Due to the presence of a small number of defects introduced by gamma irradiation, nanoribbons are photoluminescent in the UV and blue region of the visible spectrum.

  8. Positron generation through laser Compton scattering gamma ray

    International Nuclear Information System (INIS)

    The positron source is developed through a high brightness gamma-ray beam, which is produced from a laser light scattering off a high-energy electron beam circulating in a storage ring. A thin Pb target is irradiated by the gamma ray to generate positrons via pair creation. By using imaging plate, we measured the generation rate and worked out the energy spectrum of generated positrons and electrons. The experimental results are close to that from Monte Carlo simulation. About 3618 positrons/s at several MeV can be generated by the present experimental setup, and this value can be improved by optimizing experimental conditions

  9. Gamma-ray shielding properties of some travertines in Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Akkurt, Iskender; Guenoglu, Kadir [Suleyman Demirel University, Faculty of Arts and Sciences, Department of Physics, Isparta (Turkey)

    2012-09-06

    The radiation is an essential phenomenon in daily life. There are various amounts of radioactivite substances in the underground and the earth was irradiated by this substances. Humans are exposed to various kind of radiation from these sources. The travertines are usually used as a coating material in buildings. In this study, the photon attenuation coefficients of some travertines have been measured using a gamma spectroscopy with NaI(Tl) detector. The measurements have been performed using {sup 60}Co source which gives 1173 and 1332 keV energies gamma rays and {sup 137}Cs source which gives 662 keV energy gamma rays and the results will be discussed.

  10. Gamma-ray shielding properties of some travertines in Turkey

    International Nuclear Information System (INIS)

    The radiation is an essential phenomenon in daily life. There are various amounts of radioactivite substances in the underground and the earth was irradiated by this substances. Humans are exposed to various kind of radiation from these sources. The travertines are usually used as a coating material in buildings. In this study, the photon attenuation coefficients of some travertines have been measured using a gamma spectroscopy with NaI(Tl) detector. The measurements have been performed using 60Co source which gives 1173 and 1332 keV energies gamma rays and 137Cs source which gives 662 keV energy gamma rays and the results will be discussed.

  11. Oligonucleotide chip assay for quantification of gamma ray-induced single strand breaks.

    Science.gov (United States)

    Ki, Hyeon A; Kim, Min Jung; Pal, Sukdeb; Song, Joon Myong

    2009-02-20

    An oligonucleotide chip assay was designed for direct quantification of single strand breaks (SSBs) induced by gamma-ray irradiation. The oligonucleotides used were 20-mers, which were short enough to produce only a single strand break within a single oligonucleotide. The two ends of the oligonucleotides were labeled with fluorescein and biotin, respectively. The biotinylated ends of the oligonucleotides were immobilized on a silicon wafer chip treated with (3-aminopropyl)triethoxysilane (APTES), glutaraldehyde, and avidin. The DNA fragments cleaved by gamma-ray irradiation were detected by a laser-induced fluorescence (LIF) detection system. The gamma-ray-induced SSBs were quantified using a calibration curve (fluorescence intensity versus gamma-ray dose) without the need for complicated mathematical calculation based on gel-based separation. The experimentally determined gamma-ray-induced SSBs yield was almost equal to the theoretical value derived from gel electrophoresis of plasmid DNAs and DNA surface coverage. PMID:19128912

  12. Gamma ray bursts, gamma ray spectroscopy, pulsars, and very high energy gamma rays

    International Nuclear Information System (INIS)

    The origin of the 5 Mar 79 gamma ray burst is still being disputed intensely. Variable line and continuum emission from the galactic center have been measured, leading to the speculation that a massive black hole may be at origin of this emission. The strong cyclotron features in the spectrum of Her X-1 have been remeasured by two groups, one using a high resolution Germanium detector for the first time on this source. New results are presented on the Vela X-1, Crab, and A0535+26 pulsars. Very high energy gamma ray emission from Cyg X-3 has been confirmed, but the results for the Crab are still contradictory

  13. Utility of 177mLu co-produced with 177Lu from neutron irradiated enriched 176Lu2O3 as a reference standard for gamma ray spectrometry

    International Nuclear Information System (INIS)

    177mLu having half life 160.5 d and wide range of multiple gamma emissions associated with its radioactive decay could be envisaged as an attractive option as a reference standard in gamma ray spectrometry. Large-scale production and supply of medically important 177Lu to different nuclear medicine centres is a regular feature in Radiopharmaceuticals Division, BARC. A method was optimised to isolate and utilise 177mLu co-produced with 177Lu. Thermal neutron irradiation 200 g of enriched Lu2O3 (82% in 176Lu) yielded 0.0037±0.0006% of 177mLu of the 177Lu produced at end of irradiation. The strategy of using delay and decay (>20 T1/2 of 177Lu) to the control samples of regular 177Lu production batches resulted in recovery of 5.4±1.1 MBq of 177mLu per batch. Radionuclidically pure 177mLu could be utilized for preparation of standard reference sources for energy and efficiency calibration of HPGe detector in the energy range of 63-400 keV. (author)

  14. Co-expression of antioxidant enzymes with expression of p53, DNA repair, and heat shock protein genes in the gamma ray-irradiated hermaphroditic fish Kryptolebias marmoratus larvae

    Energy Technology Data Exchange (ETDEWEB)

    Rhee, Jae-Sung [Research Institute for Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Kim, Bo-Mi; Kim, Ryeo-Ok [Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Seo, Jung Soo [Pathology Team, National Fisheries Research and Development Institute, Busan 619-902 (Korea, Republic of); Kim, Il-Chan [Division of Life Sciences, Korea Polar Research Institute, Korea Institute of Ocean Science and Technology, Incheon 406-840 (Korea, Republic of); Lee, Young-Mi, E-mail: ymlee70@smu.ac.kr [Department of Green Life Science, College of Convergence, Sangmyung University, Seoul 110-743 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@hanyang.ac.kr [Research Institute for Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2013-09-15

    Highlights: •Novel identification of DNA repair-related genes in fish. •Investigation of whole expression profiling of DNA repair genes upon gamma radiation. •Analysis of effects of gamma radiation on antioxidant system and cell stress proteins. •Usefulness of verification of pathway-based profiling for mechanistic understanding. -- Abstract: To investigate effects of gamma ray irradiation in the hermaphroditic fish, Kryptolebias marmoratus larvae, we checked expression of p53, DNA repair, and heat shock protein genes with several antioxidant enzyme activities by quantitative real-time RT-PCR and biochemical methods in response to different doses of gamma radiation. As a result, the level of gamma radiation-induced DNA damage was initiated after 4 Gy of radiation, and biochemical and molecular damage became substantial from 8 Gy. In particular, several DNA repair mechanism-related genes were significantly modulated in the 6 Gy gamma radiation-exposed fish larvae, suggesting that upregulation of such DNA repair genes was closely associated with cell survival after gamma irradiation. The mRNA expression of p53 and most hsps was also significantly upregulated at high doses of gamma radiation related to cellular damage. This finding indicates that gamma radiation can induce oxidative stress with associated antioxidant enzyme activities, and linked to modulation of the expression of DNA repair-related genes as one of the defense mechanisms against radiation damage. This study provides a better understanding of the molecular mode of action of defense mechanisms upon gamma radiation in fish larvae.

  15. Co-expression of antioxidant enzymes with expression of p53, DNA repair, and heat shock protein genes in the gamma ray-irradiated hermaphroditic fish Kryptolebias marmoratus larvae

    International Nuclear Information System (INIS)

    Highlights: •Novel identification of DNA repair-related genes in fish. •Investigation of whole expression profiling of DNA repair genes upon gamma radiation. •Analysis of effects of gamma radiation on antioxidant system and cell stress proteins. •Usefulness of verification of pathway-based profiling for mechanistic understanding. -- Abstract: To investigate effects of gamma ray irradiation in the hermaphroditic fish, Kryptolebias marmoratus larvae, we checked expression of p53, DNA repair, and heat shock protein genes with several antioxidant enzyme activities by quantitative real-time RT-PCR and biochemical methods in response to different doses of gamma radiation. As a result, the level of gamma radiation-induced DNA damage was initiated after 4 Gy of radiation, and biochemical and molecular damage became substantial from 8 Gy. In particular, several DNA repair mechanism-related genes were significantly modulated in the 6 Gy gamma radiation-exposed fish larvae, suggesting that upregulation of such DNA repair genes was closely associated with cell survival after gamma irradiation. The mRNA expression of p53 and most hsps was also significantly upregulated at high doses of gamma radiation related to cellular damage. This finding indicates that gamma radiation can induce oxidative stress with associated antioxidant enzyme activities, and linked to modulation of the expression of DNA repair-related genes as one of the defense mechanisms against radiation damage. This study provides a better understanding of the molecular mode of action of defense mechanisms upon gamma radiation in fish larvae

  16. Gamma ray astronomy with Antares

    OpenAIRE

    Guillard, Goulven; collaboration, for the ANTARES

    2009-01-01

    It has been suggested that underwater neutrino telescopes could detect muons from gamma ray showers. Antares' ability to detect high energy muons produced by TeV photons is discussed in the light of a full Monte Carlo study. It is shown that currently known sources would be hardly detectable

  17. The Gamma-ray Universe through Fermi

    Science.gov (United States)

    Thompson, David J.

    2012-01-01

    Gamma rays, the most powerful form of light, reveal extreme conditions in the Universe. The Fermi Gamma-ray Space Telescope and its smaller cousin AGILE have been exploring the gamma-ray sky for several years, enabling a search for powerful transients like gamma-ray bursts, novae, solar flares, and flaring active galactic nuclei, as well as long-term studies including pulsars, binary systems, supernova remnants, and searches for predicted sources of gamma rays such as dark matter annihilation. Some results include a stringent limit on Lorentz invariance derived from a gamma-ray burst, unexpected gamma-ray variability from the Crab Nebula, a huge ga.nuna-ray structure associated with the center of our galaxy, surprising behavior from some gamma-ray binary systems, and a possible constraint on some WIMP models for dark matter.

  18. Cosmic Rays: What Gamma Rays Can Say

    OpenAIRE

    Aloisio, Roberto

    2014-01-01

    We will review the main channels of gamma ray emission due to the acceleration and propagation of cosmic rays, discussing the cases of both galactic and extra-galactic cosmic rays and their connection with gamma rays observations.

  19. The Gamma-ray Sky with Fermi

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, D.J. [NASA Goddard Space Flight Center, Greenbelt, Maryland, 20771 (United States)

    2013-10-15

    Gamma rays reveal extreme, nonthermal conditions in the Universe. The Fermi Gamma-ray Space Telescope has been exploring the gamma-ray sky for more than four years, enabling a search for powerful transients like gamma-ray bursts, solar flares, and flaring active galactic nuclei, as well as long-term studies including pulsars, binary systems, supernova remnants, and searches for predicted sources of gamma rays such as clusters of galaxies. Some results include a stringent limit on Lorentz invariance violation derived from a gamma-ray burst, unexpected gamma-ray variability from the Crab Nebula, a huge gamma-ray structure in the direction of the center of our Galaxy, and strong constraints on some Weakly Interacting Massive Particle (WIMP) models for dark matter.

  20. Laser Compton back-scattering gamma-ray beamline on NewSUBARU

    International Nuclear Information System (INIS)

    A laser-Compton scattering system is a unique and useful gamma-ray-beam source. The laser-Compton scattering gamma ray generation was tested on a synchrotron radiation facility, 'NewSUBARU' at Lasti/UH. Cw Nd:YVO laser (wavelength: 1.064?m, maximum power: 5W) was used in the experiments. Maximum energies of scattered gamma ray are 17.6 and 39.1MeV at the operating electron energy of 1 and 1.5GeV, respectively. Generated gamma-ray was measured and used in the shielding tunnel of 45cm thickness concrete wall. A scintillation detector (NaI) and Ge detector were used to measure the gamma-ray spectrum and the yield. A measured gamma-ray yield of 5x103photons/s/mA/W is in agreement with calculation. A spatial distribution of gamma-ray and its dependence on a polarization of incident laser were measured using imaging plate (IP). Preliminary experiments of gamma-ray application were performed for a nuclear transmutation in the disposal of the radioactive nuclear waste and on a gamma-ray radiography for nondestructive testing of a thick subject. New radiation shielding for the gamma-ray beamline was designed for extracting the higher flux gamma-rays for application. Radiation leakage was calculated by EGS4 and MCNPX. The calculations of neutron transport are important for observation of fast neutron generated from a target sample irradiated by gamma-ray beam

  1. Light Curves of Swift Gamma Ray Bursts

    OpenAIRE

    Cea, Paolo

    2006-01-01

    Recent observations from the Swift gamma-ray burst mission indicate that a fraction of gamma ray bursts are characterized by a canonical behaviour of the X-ray afterglows. We present an effective theory which allows us to account for X-ray light curves of both (short - long) gamma ray bursts and X-ray rich flashes. We propose that gamma ray bursts originate from massive magnetic powered pulsars.

  2. Portable compton gamma-ray detection system

    Science.gov (United States)

    Rowland, Mark S. (Alamo, CA); Oldaker, Mark E. (Pleasanton, CA)

    2008-03-04

    A Compton scattered gamma-ray detector system. The system comprises a gamma-ray spectrometer and an annular array of individual scintillators. The scintillators are positioned so that they are arrayed around the gamma-ray spectrometer. The annular array of individual scintillators includes a first scintillator. A radiation shield is positioned around the first scintillator. A multi-channel analyzer is operatively connected to the gamma-ray spectrometer and the annular array of individual scintillators.

  3. Repeated 0.5 Gy gamma-ray irradiation attenuates autoimmune disease in MRL-lpr/lpr mice with up-regulation of regulatory T cells

    International Nuclear Information System (INIS)

    Complete text of publication follows. MRL-lpr/lpr mice present a single gene mutation on the Fas (CD95) gene that leads to reduced signaling for apoptosis. With aging, these mice spontaneously develop autoimmune disease and are used as a model of systemic lupus erythematosus. We previously reported attenuation of autoimmune disease in MRL-lpr/lpr mice by repeated ?-ray irradiation (0.5 Gy each time). In this study, we investigated the mechanisms of this attenuation focusing the highly activated CD3+CD4-CD8-B220+ T cells, which are characteristically involved in autoimmune pathology in these mice. We measured the weight of the spleen and the population of CD3+CD4-CD8-B220+ T cells. Splenomegaly and increase in percentage of CD3+CD4-CD8-B220+ T cells, which occur with aging in non-irradiated mice, were suppressed in irradiated mice. To investigate the function of CD3+CD4-CD8-B220+ T cells, we isolated these cells from splenocytes by magnetic cell sorting. Isolated CD3+CD4-CD8-B220+ T cells were more resistant to irradiation-induced cell death than isolated CD4+ T cells. Although high proliferation rate and IL-6 production were observed in isolated CD3+CD4-CD8-B220+ T cells, the proliferation rate an T cells, the proliferation rate and IL-6 production were lower in the cells isolated from the irradiated mice. Moreover, the production of autoantibodies (anti-collagen antibody and anti-single strand DNA antibody) was also lowered by irradiation. These results indicate that activation of CD3+CD4-CD8-B220+ T cells and progression of pathology would be suppressed by repeated 0.5 Gy ?-ray irradiation. To uncover the mechanism of the immune suppression, we analyzed population of regulatory T cells (CD4+CD25+Foxp3+), which suppress activated T cells and excessive autoimmune responses. Intriguingly, significant increase of the percentage of regulatory T cells was observed in irradiated mice. In conclusion, we found that repeated 0.5 Gy ?-ray irradiation suppresses proliferation rate of CD3+CD4-CD8-B220+ T cells and productions of IL-6 and autoantibodies, and up-regulates regulatory T cells. These results indicate that up-regulation of regulatory T cells would involve in these therapeutic effects induced by irradiation. The up-regulation of regulatory T cells induced by irradiation could be a novel and important observation in low-dose irradiation-mediated therapeutic effects.

  4. Stellar Sources of Gamma-ray Bursts

    OpenAIRE

    Luchkov, B. I.

    2011-01-01

    Correlation analysis of Swift gamma-ray burst coordinates and nearby star locations (catalog Gliese) reveals 4 coincidences with good angular accuracy. The random probability is 4\\times 10^{-5}, so evidencing that coincident stars are indeed gamma-ray burst sources. Some additional search of stellar gamma-ray bursts is discussed.

  5. Multifrequency Observations of Gamma-Ray Burst

    OpenAIRE

    Greiner, J.

    1995-01-01

    Neither a flaring nor a quiescent counterpart to a gamma-ray burst has yet been convincingly identified at any wavelength region. The present status of the search for counterparts of classical gamma-ray bursts is given. Particular emphasis is put on the search for flaring counterparts, i.e. emission during or shortly after the gamma-ray emission.

  6. Preliminary study of a gamma-ray telescope relevant to neutron personnel dosimetry

    International Nuclear Information System (INIS)

    The objective was to use a gamma-ray dosemeter worn on the body to measure the neutron dose equivalent in the energy range <10 keV. It has been shown for cobalt 60 gamma rays that the reading of a 0.4 mm-thick LiF thermoluminescent dosemeter is only about half as large if irradiated just behind a Pb layer as if irradiated just in front of it. This report examines the possibility of using the ratio of TLD readings from dosemeters on opposite sides of a Pb filter as a measure of the relative dose contributions of gamma rays travelling in opposite directions

  7. Induction and repair of strand breaks and 3'-hydroxy terminals in the DNA of mammalian cells in culture following gamma-ray irradiation

    International Nuclear Information System (INIS)

    DNA was isolated in a fairly pure and intact state from cultured mouse leukaemia cells (L5178Y) after ?-ray irradiation using a hydroxyapatite column chromatography method, and analysed further by sucrose gradient centrifugation or DNA polymerase (EC 2.7.7.7, enzyme A of Klenow from Escherichia coli) assay. Irradiation of the cells induced single- and double-strand breaks in the DNA with an efficiency of 100 eV/break and 1300 eV/break, respectively. Approximately 50% of the single-strand breaks were estimated to be those arising from alkali-labile lesions. A linear, dose-dependent increase was found in the template activity of the DNA, indicating the induction of 3'-OH terminals by ?-irradiation. Post-irradiation incubation of the cells in serum-free medium allowed the majority of the breaks to rejoin within a few hours. Repair of the alkali-labile lesions was, however, found to be much slower than that of 'actual' single-strand breaks. A slight increase of the DNA template activity was found during the period of post-irradiation incubation. The reason for the increase is discussed

  8. Prompt Gamma Ray Measurement Facilities at Japan Research Reactor-3 (JRR-3)

    International Nuclear Information System (INIS)

    This paper briefly describes the present status of the two prompt gamma ray measurement facilities, PGA and MPGA, installed on neutron beam lines attached to Japan Research Reactor-3 (JRR-3). The description includes those on the configuration of the beam line as well as the supporting system of the irradiation sample, neutron intensity at the irradiation position, and detectors used for the prompt gamma ray measurement, for each of the facilities. (author)

  9. Saturation of polymer yield during postpolymerization of gamma-ray irradiated 2-amino-4-N-methylanilino-6-isopropenyl-1,3,5-triazine

    International Nuclear Information System (INIS)

    The postpolymerization of 2-amino-4-N-methylanilino-6-isopropenyl-1,3,5-triazine (AMIT) irradiated in glassy-state with ?-ray of 60Co at -780C was investigated. The DSC of AMIT irradiated in glassy-state showed a glass-transition temperature at 160C and an exothermic peak due to polymerization at temperature near 410C. This fact shows that the active species are trapped in the glass without causing polymerization until the glass-transition temperature is reached. The post-polymerization at 30 -- 1100C of samples irradiated at -780C gave polymers in saturated yields which depend on the polymerization temperature. It is shown by the measurement of ESR spectra and Gordon-Taylor's plot that a cause of the saturation of the polymer yield is not the disappearance of the active species but the glass formation of the polymer and monomer mixture during the postpolymerization. (auth.)

  10. Health effects of low-level irradiation during development: experimental design and prenatal and early neonatal mortality in beagles exposed to 60Co gamma rays

    International Nuclear Information System (INIS)

    As part of a long-term study of the effects of irradiation during development, prenatal and early neonatal mortality were evaluated for beagles exposed in utero at 8 days postcoitus (dpc), 28 dpc, 55 dpc, or 2 days postpartum. Mean doses used were 0,0.16, or 0.83 Gy. A decrease in whelping rates was observed for female breeders irradiated at 8 dpc. There was a significant decrease in litter sizes from female breeders irradiated at 8 and 28 dpc. Both of these findings are indicative of increased embryonic mortality. There was a significant decrease in the percentage of females born after exposures given at 28 dpc, indicating a differential radiosensitivity by sex. A significant increase in early neonatal mortality up to 14 days of age was observed for beagles exposed 8 or 28 dpc, again with an excess mortality in females

  11. Body weight and enzymes activities in blood plasma of chickens hatched from eggs irradiated with low level gamma rays before incubation

    Directory of Open Access Journals (Sweden)

    Kraljevi? Petar

    2009-01-01

    Full Text Available An attempt was made to determine the effect of eggs irradiation by low dose gamma radiation upon body weight (BW, body weight gain (BWG, feed consumption (FC and feed conversion ratio (FCR of chickens hatched from irradiated eggs. Our aim was also to investigate the activity of aspartate aminotransferase (AST, alanine aminotransferase (ALT, acid phosphatase (ACP and alkaline phosphatase (ALP in the blood plasma of those chickens. The eggs of heavy breed chickens were irradiated with a dose of 0.15 Gy gamma radiation (60Co before incubation. Along with the chickens which were hatched from irradiated eggs, there was a control group of chickens hatched from nonirradiated eggs. All other conditions were the same for both groups of chickens. BW of chickens was measured by a single weighting of chickens on the 1st and 42nd day of the fattening period. An average BWG was calculated from the obtained results during the whole fattening period (i.e. from the 1st until the 42nd day. FC was measured each day during the fattening time and total feed consumption was calculated. On the basis of FC and BW, FCR was calculated (FC/BWG. Blood samples were taken from the right jugular vein on the 1st and 3rd day, or from the wing vein on days 5, 7, 10, 20, 30 and 42. The activity of all enzymes was determined spectrophotometrically by using reagents according to recommendations of the International Federation of Clinical Chemistry and Laboratory Medicine. BW of chickens hatched from irradiated eggs was statistically significant higher than in the controls during the fattening period; on day 42 of fattening, BW of the experimental chickens was 90 g (i.e. 4.8 % higher than in the controls (P<0.05. FC during the fattening period did not essentially differ in the experimental and the control group. The AST activity was significantly increased in blood plasma of chickens hatched from irradiated eggs on days 3 and 10 (P<0.05, ALT activity was increased in the same chickens only on the 10th day (P<0.05. The activity of ACP in the blood plasma of the same chickens was increased on day 42 (P<0.001 and the activity of ALP in the blood plasma of chickens hatched from irradiated eggs was decreased on day 42 (P<0.001. The obtained results indicate that low doses of gamma radiation have a stimulative effect upon metabolic processes in chickens hatched from eggs irradiated before incubation, which is proved by increase of BWG and BW, as well as by increase of AST, ALT and ACP activities in blood plasma.

  12. Differential effect of procaine on irradiated mammalian cells in culture. [. gamma. rays; HeLa cells; V-79 Chinese hamster cells

    Energy Technology Data Exchange (ETDEWEB)

    Djordjevic, B.

    1979-05-01

    HeLa and V-79 Chinese hamster cells temporarily stored in ampoules were treated with the local anesthetic procaine. Postirradiation treatment increased lethality in HeLa cells depending on drug concentration, duration of treatment, and cell density, as measured by colony-forming ability upon plating. If present during irradiation only, procaine protected from irradiation. In V-79 cells, procaine potentiated radiation lethality only in freshly trypsinized cells. Procaine effect was thus cell type specific and most likely involved the cell membrane.

  13. Effect of serial irradiation of low dose gamma rays on the growth and photosynthesis of red pepper (capsicum annuum L.) plants

    International Nuclear Information System (INIS)

    Ionizing radiation at several grays can induce growth stimulation in plants. This phenomenon has been called 'radiation hormesis'. Low dose radiation also modulates photosynthesis. Although an alteration in photosynthesis has been thought to involve in the growth stimulation of irradiated plants, no reports did clarify their relationship yet. In the present study, we attempted to reveal a possible relationship between them by comparing the effects of serial gamma-irradiation on the growth and photosynthesis of red pepper. Furthermore, something beyond the dose effect of ionizing radiation is discussed by this new experimental approach

  14. Compton suppression gamma ray spectrometry

    International Nuclear Information System (INIS)

    In the past decade there have been many studies to use Compton suppression methods in routine neutron activation analysis as well as in the traditional role of low level gamma ray counting of environmental samples. On a separate path there have been many new PC based software packages that have been developed to enhance photopeak fitting. Although the newer PC based algorithms have had significant improvements, they still suffer from being effectively used in weak gamma ray lines in natural samples or in neutron activated samples that have very high Compton backgrounds. We have completed a series of experiments to show the usefulness of Compton suppression. As well we have shown the pitfalls when using Compton suppression methods for high counting deadtimes as in the case of neutron activated samples. We have also investigated if counting statistics are the same both suppressed and normal modes. Results are presented in four separate experiments. (author)

  15. Airborne gamma ray spectrometer surveying

    International Nuclear Information System (INIS)

    The International Atomic Energy Agency (IAEA) in its role as collector and disseminator of information on nuclear techniques has long had an interest in gamma ray spectrometer methods and has published a number of Technical Reports on various aspects of the subject. At an Advisory Group Meeting held in Vienna in November 1986 to review appropriate activities the IAEA could take following the Chernobyl accident, it was recommended that preparation begin on a new Technical Report on airborne gamma ray spectrometer surveying, taking into account the use of the technique for environmental monitoring as well as for nuclear emergency response requirements. Shortly thereafter the IAEA became the lead organization in the Radioelement Geochemical Mapping section of the International Geological Correlation Programme/United Nations Educational, Scientific and Cultural Organization (UNESCO) Project on International Geochemical Mapping. These two factors led to the preparation of the present Technical Report. 18 figs, 4 tabs

  16. Zeptosecond $\\gamma$-ray pulses

    OpenAIRE

    Klaiber, Michael; Hatsagortsyan, Karen Z.; Keitel, Christoph H.

    2007-01-01

    High-order harmonic generation (HHG) in the relativistic regime is employed to obtain zeptosecond pulses of $\\gamma$-rays. The harmonics are generated from atomic systems in counterpropagating strong attosecond laser pulse trains of linear polarization. In this setup recollisions of the ionized electrons can be achieved in the highly relativistic regime via a reversal of the commonly deteriorating drift and without instability of the electron dynamics such as in a standing l...

  17. Gamma-ray Burst Energetics

    OpenAIRE

    Kumar, Pawan

    1999-01-01

    We estimate the fraction of the total energy in a Gamma-Ray Burst (GRB) that is radiated in photons during the main burst. Random internal collisions among different shells limit the efficiency for converting bulk kinetic energy to photons. About 1% of the energy of explosion is converted to radiation, in 10-1000 kev energy band in the observer frame, for long duration bursts (lasting 10s or more); the efficiency is significantly smaller for shorter duration bursts. Moreover...

  18. Expressed sequence tags isolated from mouse bone marrow cells irradiated with high-dose gamma rays by suppression subtractive hybridization (SSH)

    International Nuclear Information System (INIS)

    Objective: To explore the molecular mechanism of bone marrow injury caused by irradiation, gene expression of bone marrow cells in mice after whole body irradiation was studied. Methods: Total RNA extracted from bone marrow cells in mice at 4 h after whole body irradiation with 7 Gy ?-rays was taken as the tester and the total RNA from control mice as the driver cDNA subtraction was performed using the protocols described in the Clontech SMART PCR cDNA Sythesis Kit and PCR-select cDNA Subtraction Kit. The subtracted cDNA was then inserted into T vector to generate subtracted cDNA library. Clones of the subtracted cDNA library were screened by hybridization and the insert sequence of the positive clones was compared with the sequence in the GenBank. Results: A total of 800 clones selected from the subtracted cDNA library were PCR-amplified and about 86% had inserts. Fourteen differential cDNA fragments were acquired after two round hybridization screening, 7 of them showed high similarity to the expressed sequence tags (ESTs) in the mouse EST database and the other 7 cDNA fragments were possibly new ESTs. Conclusion: The successfully constructed subtracted cDNA library of bone marrow cells in mice after whole body high-dose irradiation and the validation of some differential ESTs establish the basis for further research of radiation-related genes

  19. DUAL Gamma-Ray Mission

    CERN Document Server

    Boggs, S; von Ballmoos, P; Takahashi, T; Gehrels, N; Tueller, J; Baring, M; Beacom, J; Diehl, R; Greiner, J; Grove, E; Hartmann, D; Hernanz, M; Jean, P; Johnson, N; Kanbach, G; Kippen, M; Knödlseder, J; Leising, M; Madejski, G; McConnell, M; Milne, P; Motohide, K; Nakazawa, K; Oberlack, U; Phlips, B; Ryan, J; Skinner, G; Starrfield, S; Tajima, H; Wulf, E; Zoglauer, A; Zych, A

    2010-01-01

    Gamma-ray astronomy presents an extraordinary scientific potential for the study of the most powerful sources and the most violent events in the Universe. In order to take full advantage of this potential, the next generation of instrumentation for this domain will have to achieve an improvement in sensitivity over present technologies of at least an order of magnitude. The DUAL mission concept takes up this challenge in two complementary ways: a very long observation of the entire sky, combined with a large collection area for simultaneous observations of Type Ia SNe. While the Wide-Field Compton Telescope (WCT) accumulates data from the full gamma-ray sky (0.1-10 MeV) over the entire mission lifetime, the Laue-Lens Telescope (LLT) focuses on 56Co emission from SNe Ia (0.8-0.9 MeV), collecting gamma-rays from its large area crystal lens onto the WCT. Two separated spacecraft flying in formation will maintain the DUAL payloads at the lens' focal distance.

  20. Process for producing a collagen web for a transparent artificial cornea and a contact lens by irradiation with ultraviolet or gamma rays

    International Nuclear Information System (INIS)

    A process for producing a collagen web for use as an artificial cornea and a contact lens is provided by irradiating an acid soluble collagen web or a swelled collagen web with ultraviolet rays or gamma radiation. Cross-linking is introduced into the molecules forming a noncrystalline portion of the collagen to minimize nonuniformity of construction. In embodiments, the collagen, dissolved in a diluted hydrochloric acid or acetic acid aqueous solution at a concentration of about 0.5% to 1%(pH 2-4), is poured into a suitable container for producing and drying a web. The obtained web is neutralized with ammoniac water or vapor and is washed completely. The web is dipped in a dilute hydrochloric acid or acetic acid aqueous solution (pH 2-4) to well and then irradiated. Cross-linking is introduced, followed by further neutralization with ammoniac vapor. Finally the web is washed, air-dried or kept in water. Alternately, the above 0.5%-1% collagen solution is irradiated to gelatinize it after the oxygen dissolved in the solution is substituted with nitrogen. The irradiated web is neutralized with ammoniac water or vapor, and then washed, air-dried or kept in water. In one example, 0.58% collagen hydrochloric acid solution was poured into a methylmethacrylate box and was air-dried to form a web 0.03mm in thickness. The web was neutralized with ammoniac vapor for 24 hours and dipped to swell in a 0.01N HCl solution for 1 minute. The opposite sides of the web were irradiated with UV-rays at 15W. (Iwakiri, K.)

  1. Ion-induced gamma-ray detection of fast ions escaping from fusion plasmas

    International Nuclear Information System (INIS)

    A 12 × 12 pixel detector has been developed and used in a laboratory experiment for lost fast-ion diagnostics. With gamma rays in the MeV range originating from nuclear reactions 9Be(?, n?)12C, 9Be(d, n?)12C, and 12C(d, p?)13C, a high purity germanium (HPGe) detector measured a fine-energy-resolved spectrum of gamma rays. The HPGe detector enables the survey of background-gamma rays and Doppler-shifted photo peak shapes. In the experiments, the pixel detector produces a gamma-ray image reconstructed from the energy spectrum obtained from total photon counts of irradiation passing through the detector's lead collimator. From gamma-ray image, diagnostics are able to produce an analysis of the fast ion loss onto the first wall in principle

  2. Ion-induced gamma-ray detection of fast ions escaping from fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Nishiura, M., E-mail: nishiura@ppl.k.u-tokyo.ac.jp; Mushiake, T. [Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8561 (Japan); Doi, K.; Wada, M. [Graduate School of Science and Engineering, Doshisha University, Kyotanabe 610-0321 (Japan); Taniike, A.; Matsuki, T. [Graduate School of Maritime Sciences, Kobe University, Kobe 658-0022 (Japan); Shimazoe, K. [Graduate School of Engineering, The University of Tokyo, Tokyo 113-8654 (Japan); Yoshino, M. [Furukawa Co. Ltd., Tsukuba, Ibaraki 305-0856 (Japan); Nagasaka, T.; Tanaka, T.; Kisaki, M. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Fujimoto, Y.; Fujioka, K. [Institute of Laser Engineering, Osaka University, Osaka 565-0871 (Japan); Yamaoka, H. [RIKEN SPring-8 center, RIKEN, Sayo, Hyogo 679-5148 (Japan); Matsumoto, Y. [Tokushima Bunri University, Tokushima 770-8514 (Japan)

    2014-11-15

    A 12 × 12 pixel detector has been developed and used in a laboratory experiment for lost fast-ion diagnostics. With gamma rays in the MeV range originating from nuclear reactions {sup 9}Be(?, n?){sup 12}C, {sup 9}Be(d, n?){sup 12}C, and {sup 12}C(d, p?){sup 13}C, a high purity germanium (HPGe) detector measured a fine-energy-resolved spectrum of gamma rays. The HPGe detector enables the survey of background-gamma rays and Doppler-shifted photo peak shapes. In the experiments, the pixel detector produces a gamma-ray image reconstructed from the energy spectrum obtained from total photon counts of irradiation passing through the detector's lead collimator. From gamma-ray image, diagnostics are able to produce an analysis of the fast ion loss onto the first wall in principle.

  3. Ion-induced gamma-ray detection of fast ions escaping from fusion plasmas.

    Science.gov (United States)

    Nishiura, M; Doi, K; Taniike, A; Matsuki, T; Shimazoe, K; Mushiake, T; Yoshino, M; Nagasaka, T; Fujimoto, Y; Fujioka, K; Tanaka, T; Kisaki, M; Yamaoka, H; Matsumoto, Y; Wada, M

    2014-11-01

    A 12 × 12 pixel detector has been developed and used in a laboratory experiment for lost fast-ion diagnostics. With gamma rays in the MeV range originating from nuclear reactions (9)Be(?, n?)(12)C, (9)Be(d, n?)(12)C, and (12)C(d, p?)(13)C, a high purity germanium (HPGe) detector measured a fine-energy-resolved spectrum of gamma rays. The HPGe detector enables the survey of background-gamma rays and Doppler-shifted photo peak shapes. In the experiments, the pixel detector produces a gamma-ray image reconstructed from the energy spectrum obtained from total photon counts of irradiation passing through the detector's lead collimator. From gamma-ray image, diagnostics are able to produce an analysis of the fast ion loss onto the first wall in principle. PMID:25430369

  4. Effect of gamma rays on adult flight agility and distribution of Old World screwworm, Chrysomya bezziana, irradiated at the pupal stage

    International Nuclear Information System (INIS)

    The larvae of Old World screwworm, Chrysomya bezziana were reared on a meat-based diet containing: lean minced beef (54%), fresh blood (15% containing 10% EDTA), water (30%) and formalin (0.2%). The developed pupae were separated in plastic containers containing vermiculite or corncob grits and incubated for adult emergence under 28 deg. C and 70% relative humidity. The emerged adults were transferred into the adult cages (made from cloth tissue, black or white), provided with water, honey and sugar. Radiation Treatments: At the 5th day of female age, egging dishes were prepared from ground meat, clotted blood or pieces of liver, oviposition stimulants deg. Cntaining spent medium immersed inside the dish. All the contents were warmed on a hotplate to 37 - 39 deg. C. The egging dishes were provided daily for two hours inside the cage for egg deposition. Egg masses and newly hatched larvae were taken for establishing the laboratory colony. The average larval period was 6.8 days, rate of pupation 93.2%, pupal period 7.6 days and rate of pupal development 79%. Pupae at 2-5 days were irradiated with a Gammacell 220. Percentage pupal development to adults decreased from 82% for non-irradiated pupae, to 3%, 12%, 29% and 22% for pupae irradiated with a dose of 90 Gy at 2, 3, 4 and 6 days age. The lifespan of adults emerged from irradiated pupae decreased with increasing gamma dose. Sixty Gy or less did not have an effect on the ovarian development. No egg hatch resulted from n development. No egg hatch resulted from the crosses between treatments of 60 to 90 Gy. Egg hatch was observed only in normal adult crosses or in normal females mated with males emerged from 45 Gy irradiated pupae. Flight Agility Test: A small cylinder was made from transparent paper (10 cm long X 10 cm diameter) and lined by baby powder to avoid adults walking out of the cylinder. A group of adults (newly emerged from irradiated pupae) were left inside each cylinder under appropriate temperature and humidity. Adults with flight ability escaped from the cylinder, and were caught by sticky papers hung inside the room. The Flight Agility Index (F.A.I.) was calculated by using an equation

  5. Decomposition of hydrogen peroxide on a ZnO-CdO two-component catalyst; influence of ionizing radiation. [Gamma rays or fast neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mucka, V.; Pavek, J.

    1982-01-01

    Decomposition of hydrogen peroxide in aqueous solution (1.2 mol/l) was studied on zinc oxide-cadmium oxide two component catalysts before and after gamma or fast neutron irradiation. The samples were prepared with various proportions of the constituents covering the entire region of 0-100% of one component. The study presented evidence of mutual charge interaction between both components of the catalyst that leads to the highest catalytic activity of the sample with 2.2-3.5 mol% cadmium oxide. A pre-irradiation of the sample by gamma /sup 60/Co rays or by fast neutrons (/sup 252/Cf) leads to higher activity and the radiation-catalytic effect attains 63% and 267%, respectively. The enhancement of the activity and some more properties of the studied system can be explained on the basis of the principle of bivalent sites.

  6. Determination of ?-tyrosine production in aqueous solutions of phenylalanine irradiated with gamma ray, using high performance liquid chromatography with automated pre-column derivatization and LASER fluorometric detection

    International Nuclear Information System (INIS)

    Tyrosine isomers produced by gamma radiation of aqueous phenylalanine solutions at mid dose levels (1-10 kGy) were examined to obtain basic information for irradiated food detection using a new high performance liquid chromatography (HPLC) analytical procedure. The procedure was established using an automated pre-column derivatization with 4-fluoro-7-nitro 2,1,3-benzoxadiazole (NBD-F) followed by reverse phase HPLC and LASER fluorometric detection. The limit of detection (LOD) was 0.06 ng on-column and the linear range for calibration was 0.06 to 50 ng for the tyrosine derivatives. The relative standard deviation was 10% to 12%. The amounts of the tyrosine isomers increased with levels of irradiation. Irradiation at low temperature with reduced oxygen decreased the isomer yields. In the pH range of 5 to 7, the amount of product was not changed significantly by pH, outside this range, the pH did have an effect on product generation. At constant dose levels the yields of tyrosine isomers initially increased with phenylalanine concentration, although, with further increases in phenylalanine a reduction in the absolute amounts was observed. Dose rates varying from 0.5 kGy/h to 10 kGy/h had no significant effect on tyrosine isomer formation if a total of 10 kGy was used in each case. In addition, demonstrating the usefulness of this new analytical technique for ?-tyrosine determination, these studies suggest that the presence of ?-tyrosine is another parameter indicativetyrosine is another parameter indicative of gamma irradiation. (author)

  7. Formation of solid particles from aqueous solutions of palladium sulfate and of palladium sulfate-silver sulfate by gamma ray irradiation

    International Nuclear Information System (INIS)

    Aqueous solutions containing (a) palladium sulfate (b) palladium sulfate and silver sulfate, and (c) silver sulfate saturated with nitrogen were irradiated with cobalt 60 gamma radiations (dose rate, 2.35 and 11.2 kGy/h; temperature: 10 and 29-45degC). The pH's of the most solutions were 1.43 or 0.43. Formation of fine particles was studied from the decrease of optical absorption of the metal ions, and from mass measurement of solid precipitate. It was found that (1) palladium ion decreased with dose in the solutions (a) and (b) with appearance of continuum spectra from 200-700nm range due to solid particles, and (2) silver ion decreased with increasing dose in solution (b) while it did not decrease in solution (c), and (3) electric conductive precipitate was formed in solution (a) and solution (b), but no precipitate was found in solution (c) by the irradiation. The results indicate that (1) palladium ion was reduced to form metallic precipitate in any condition studied, but (b) silver ion was reduced only in the presence of palladium ion, and (3) bimetallic particles were formed in solution (b). The amounts of the precipitates recovered from the irradiated solutions were 57% for solution (a) and 97% for (b) of the amounts of ions reacted. (author)

  8. Study of alteration in the mechanical properties in hybrid nanocomposite of polypropylene/sisal fibers/mineral clay irradiated with gamma rays

    International Nuclear Information System (INIS)

    A new material class formed with reinforced filler, hybrid of organic and inorganic materials provides the technological development of materials with modified properties. And among great numbers of properties that can be modified by presence of hybrid filler to stand out the tension resistance. Polymer shows behavior of tensions and deformation that are not related of simple form. The answer of this material at mechanicals solicitations depends of structural factors and externals variables. As structural factors can be, for example, molecular weight, ramifications and crosslink. As external variables can be, for example, temperature, time or velocity of deformation, kind of solicitation and others. This work was possible to verify as nanostructures materials behavior, mechanically, after were submitted gamma radiation. This work utilized as polymeric matrix, recycled polypropylene, and as hybrid filler, a mixture of montimorillonite mineral clay with natural sisal fibers. It is known that form to magnify the tensile resistance is increase the number of crosslink of principal chain for gamma radiation. After irradiation the polypropylene was crosslinked structures that are result recombination of radicals formed during process of irradiation. It.s known that radicals formed occur preferentially in the amorphous region of polymer. Considering that polymeric matrix polypropylene, without addition fillers suffer strong structural influence when irradiated, was possible verify change in the extension, tensile strength and also maxim tensile in rupture, when this matrix was incorporated with fillers hybrids. (author)

  9. The effect of high gamma-ray doses on the track-registration properties of natural mica

    International Nuclear Information System (INIS)

    The effect of gamma-ray irradiation of natural mica is given in terms of the track-registration property. Specimens of muscovite mica were first exposed to various gamma-ray doses from a 60Co source ranging from 1.9 x 103 to 1.6 x 104 MRad, and then to fission fragments. The results show that the average etched width of fission-fragment tracks decreases with increasing gamma-ray dose. Shallow pits were observed in etched specimens when the gamma-ray dose exceeded 5 x 103 MRad. The number of shallow etch pits per unit area increases with increasing gamma-ray dose and depends on the local lattice structure in the specimen as well. Numerous shallow etch pits caused by the gamma-ray irradiation of the order of 104 MRad interfered with the observation of fission tracks in the specimen. Other specimens were exposed to gamma-ray doses up to 1.8 x 104 MRad after having been heated for 100 min at various temperatures up to 6000C. No shallow etch pits were observed on the surface of the specimen annealed for 100 min at 6000C before the gamma-ray irradiation. Pre-annealing extends the 'safety limits' of the gamma background below which muscovite mica can be used to observe fission tracks without any gamma-ray interference. (orig.)

  10. Effect of different doses of gamma rays and fast neutrons on growth of carrot cellus tissue

    International Nuclear Information System (INIS)

    Callus tissue lines of four carrot cultivars, grown on three nutrient media, were irradiated with doses of gamma rays from 260 to 44700 R and fast neutrons from 180 - 21000 rad. Effects similar to those of gamma rays were obtained at lower doses of fast neutrons. The response of callus tissues to irradiation was influenced both by genetic factors and the nutrient medium. Two of the irradiated lines exhibited growth stimulation at low doses and a lower sensitivity to irradiation than did the two other ones. Tissues grown on a medium without kinetin showed the highest stimulation at low doses and the lowest growth depression at higher doses of irradiation. (author)

  11. Investigation of rheological properties of the irradiated isoprene-nitrile elastomers

    International Nuclear Information System (INIS)

    Full text : The aim of this work was the investigation of flow regularities both rubbers and the irradiated blends on the basis of these rubbers in dependence of following factors : different tensions and deformation shift rate, irradiation and low-molecular product degree. The flow regularities of irradiated blends with flow of non-irradiated blends were correlated

  12. Study of electronic transport in gamma ray exposed nanowires

    International Nuclear Information System (INIS)

    Graphical abstract: A sharp decline in the I–V characteristics of Cu (and Cd) nanowires was experimentally observed after the gamma ray exposure of nanowires. Irradiation induced transformations in the granular properties and the resonance state of electron–phonon coupling beyond a particular value of external field may be accountable for observed shape of I–V characteristics in gamma ray exposed nanowires. - Highlights: • Cu and Cd nanowires were synthesized by technique of electrodeposition in templates. • The nanowires were exposed to different doses of gamma ray photons. • A sharp decline in the current in I–V characteristics (IVC) was observed. • Structural deviation in terms of granular orientations was also analysed. • The electron–phonon coupling may be responsible for observed sharp decline in IVC. - Abstract: One dimensional nanostructures provide the most restricted and narrow channel for the transport of charge carriers and therefore 1D structures preserve their significance from the viewpoint of electronic devices. The net radiation effect on nanomaterials is expected to be more (due to their increased reactivity and lesser bulk volume) than their bulk counterparts. Radiation often modifies the structure and simultaneously the other physical properties of materials. In this manner, the irradiation phenomenon could be counted as a strong criterion to induce changes in the structural and electricama rays on the electronic flow through Cu and Cd nanowires by plotting their I–V characteristics (IVC). The IVC of gamma ray exposed nanowires was found to be a combination of the linear and nonlinear regions and a decreasing pattern in the electrical conductivity (calculated from the linear portion of IVC) was observed as we increased the dose of gamma rays

  13. Gamma-ray co-irradiation induced graft polymerization of NVP and SSS onto polypropylene non-woven fabric and its blood compatibility

    International Nuclear Information System (INIS)

    Sodium styrenesulfonate was grafted onto PPNWF via ?-ray co-irradiation method with the existence of N-vinyl-2-pyrrolidone. The effect of absorbed dose, dose rate and concentration of binary monomer on the degree of grafting was investigated. The surface chemical change was characterized by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The wettability was characterized through the measurement of adsorption percentage of water and phosphate buffer solution (PBS). The result demonstrated that the grafted poly(NVP–co-SSS) chains can improve the hydrophilicity of PPNWF. Furthermore, the modified PPNWF has good blood compatibility, such as low hemolysis rate, low platelet adhesion and effectively extending the blood coagulation times. Consequently, hydrophilicity and hemocompatibility of PPNWF were greatly enhanced by the immobilization of poly(NVP–co-SSS) chains. - Highlights: • SSS was successfully grafted onto PPNWF via co-irradiation method with the addition of NVP. • The grafting kinetics was studied and the anchored chains did enhance the wettability of PPNWF. • The modified PPNWF presented good blood compatibility and excellent anticoagulation activity

  14. Influence of gamma ray irradiation and annealing temperature on the optical constants and spectral dispersion parameters of metal-free and zinc tetraphenylporphyrin thin films: A comparative study.

    Science.gov (United States)

    Zeyada, H M; Makhlouf, M M; El-Nahass, M M

    2015-09-01

    In this work, we report on the effect of ?-ray irradiation and annealing temperature on the optical properties of metal-free tetraphenylporphyrin, H2TPP, and zinc tetraphenylporphyrin, ZnTPP, thin films. Thin films of H2TPP and ZnTPP were successfully prepared by the thermal evaporation technique. The optical properties of H2TPP and ZnTPP films were investigated using spectrophotometric measurements of the transmittance and reflectance at normal incidence of light in the wavelength range from 200 to 2500nm. The absorption spectra of H2TPP showed four absorption bands, namely the Q, B, N and M bands. The effect of inserting Zn atom into the cavity of porphyrin macrocycle in ZnTPP molecule distorted the Q and B bands, reduced the width of absorption region and influenced the optical constants and dispersion parameters. In all conditions, the type of electron transition is indirect allowed transition. Anomalous dispersion is observed in the absorption region but normal dispersion occurs in the transparent region of spectra. We adopted multi-oscillator model and the single oscillator model to interpret the anomalous and normal dispersion, respectively. We have found that the annealing temperature has mostly the opposite effect of ?-ray irradiation on absorption and dispersion characteristics of these films. PMID:25911158

  15. Preparation, properties and biological application of pH-sensitive poly(ethylene oxide) (PEO) hydrogels grafted with acrylic acid(AAc) using gamma-ray irradiation

    International Nuclear Information System (INIS)

    pH-sensitive hydrogels were studied as a drug carrier for the protection of insulin from the acidic environment of the stomach before releasing it in the small intestine. In this study, hydrogels based on poly(ethylene oxide) (PEO) networks grafted with acrylic acid (AAc) were prepared via a two-step process. PEO hydrogels were prepared by ?-ray irradiation, and then grafting by AAc monomer onto the PEO hydrogels with the subsequent irradiation (radiation dose: 5-20 kGy, dose rate: 2.15 kGy/h). These grafted hydrogels showed a pH-sensitive swelling behavior. The grafted hydrogels were used as a carrier for the drug delivery systems for the controlled release of insulin. The in vitro drug release behaviors of these hydrogels were examined by quantification analysis with a UV/VIS spectrophotometer. Insulin was loaded into freeze-dried hydrogels (7 mmx3 mmx2.5 mm) and administrated orally to healthy and diabetic Wistar rats. The oral administration of insulin-loaded hydrogels to Wistar rats decreased the blood glucose levels obviously for at least 4 h due to the absorption of insulin in the gastrointestinal tract

  16. Induction of rhodanese, a detoxification enzyme, in livers from mice after long-term irradiation with low-dose-rate gamma-rays

    International Nuclear Information System (INIS)

    The health effects of low-dose radiation exposure are of public concern. Although molecular events in the cellular response to high-dose-rate radiation exposure have been fully investigated, effects of long-term exposure to extremely low-dose-rate radiation remain unclear. Protein expression was analyzed by two-dimensional electrophoresis in livers from mice irradiated for 485 days (22 hr/day) at low-dose-rates of 0.032 ?Gy/min, 0.65 ?Gy/min and 13 ?Gy/min (total doses of 21 mGy, 420 mGy and 8000 mGy, respectively). One of the proteins that showed marked changes in expression was identified as rhodanese (thiosulfate sulfurtransferase). Rhodanese expression was increased after irradiation at 0.65 ?Gy/min and 13 ?Gy/min, while its expression was not changed at 0.032 ?Gy/min. Rhodanese is a detoxification enzyme, probably related to the regulation of antioxidative function. However, antioxidative proteins, such as superoxide dismutase (SOD)1 (also known as Cu, Zn-SOD) and SOD2 (also known as Mn-SOD), which can be induced by high-dose-rate radiation, were not induced at any low-dose-rates tested. These findings indicate that rhodanese is a novel protein induced by low-dose-rate radiation, and further analysis could provide insight into the effects of extremely low-dose-rate radiation exposure. (author)

  17. The dose response relationship obtained at constant irradiation times for the induction of chromosome aberrations in human lymphocytes by cobalt-60 gamma rays

    International Nuclear Information System (INIS)

    The induction of unstable chromosome aberrations in human peripheral blood lymphocytes exposed in vitro to protracted doses of cobalt-60 radiation is presented. Four dose response curves have been produced using constant exposure times of 1, 3, 6, and 12 h. The data fit well to the linear quadratic model and the yield coefficients have been compared with those obtained for acute (<10 min) exposure. The quadratic coefficient is dependent on irradiation time and decreases approximately as predicted by Lea and Catcheside's G-function hypothesis. The possibility of a small proportion of much longer liver breaks is discussed. For purposes of biological dosimetry it is sufficient to assume a mean time of 2 h and a single exponential function for the repair of lesions when relating the effects of brief and protracted exposure. (orig.)

  18. Proton range verification through prompt gamma-ray spectroscopy

    Science.gov (United States)

    Verburg, Joost M.; Seco, Joao

    2014-12-01

    We present an experimental study of a novel method to verify the range of proton therapy beams. Differential cross sections were measured for 15 prompt gamma-ray lines from proton-nuclear interactions with 12C and 16O at proton energies up to 150 MeV. These cross sections were used to model discrete prompt gamma-ray emissions along proton pencil-beams. By fitting detected prompt gamma-ray counts to these models, we simultaneously determined the beam range and the oxygen and carbon concentration of the irradiated matter. The performance of the method was assessed in two phantoms with different elemental concentrations, using a small scale prototype detector. Based on five pencil-beams with different ranges delivering 5 × 108 protons and without prior knowledge of the elemental composition at the measurement point, the absolute range was determined with a standard deviation of 1.0–1.4 mm. Relative range shifts at the same dose level were detected with a standard deviation of 0.3–0.5 mm. The determined oxygen and carbon concentrations also agreed well with the actual values. These results show that quantitative prompt gamma-ray measurements enable knowledge of nuclear reaction cross sections to be used for precise proton range verification in the presence of tissue with an unknown composition.

  19. The effect of gamma rays on carrots

    International Nuclear Information System (INIS)

    The effects of several doses (5-400 Gy) of gamma rays from a 137Cs source were studied on several biological indices in carrots. Doses higher than 50 Gy reduced the wet weight of the cells in the suspension medium whereas the doses of 5 and 10 Gy affected the wet weight positively and to a lesser extent the dry weight. This may be due to higher water absorption of the irradiated cells since their number was less than that of the control. The different doses did not affect the chromosome number of the cells but reduced the cell division rates. At doses higher than 200 Gy no singel cell was recorded as dividing after two days of irradiation. A week later, however, the cells seemed to have recovered some ability for division, but with an increase of prophase stage in mitosis and also in the mitotic division abnormalities. Cells irradiation with 10 Gy caused the cells to differentiate and to form somatic embryos due to halting the effect of 2,4-D hormon. Higher doses, however, prohibited or reduced cells differentiation, probably due to higher mitotic division abnormalities. Nevertheless, it has been possible to attain mature plants from all treatments except for the 400 Gy. The low doses of 5 and 10 Gy, contrary to the higher ones, affected positively the speed of seed germination, increased the plant height, and also increased the root weight. 11 refs. (author)

  20. High Redshift Gamma Ray Bursts

    Science.gov (United States)

    Gehrels, Neil

    2012-01-01

    The Swift Observatory has been detecting 100 gamma-ray bursts per year for 7 years and has greatly stimulated the field with new findings. Observations are made of the X-ray and optical afterglow from 1 minute after the burst, continuing for days. GRBs are providing a new tool to study the high redshift universe. Swift has detected several events at z>5 and one at z=9.4 giving information on metallicity, star formation rate and reionization. The talk will present the latest results.

  1. Cosmology from gamma ray bursts

    International Nuclear Information System (INIS)

    In this study we propose to use Gamma Ray Bursts (GRBs) as standard candles in order to constrain the expansion history of the universe up to redshifts of z ? 6. In particular, we utilize the 69 GRB dataset recently compiled by Cardone et al. (2009). Performing a joint likelihood analysis of the recent supernovae type Ia (SNIa) data and the GRBs we can put constraints on the main cosmological parameters (?m, w). However, the use of the current GRBs to trace the Hubble relation, as an alternative to the traditionally used SNIa, can not break the degeneracy between the ?m and the dark energy equation of state parameter.

  2. Very High Energy Gamma-Ray Astronomy

    OpenAIRE

    Catanese, Michael; Weekes, Trevor C.

    1999-01-01

    We present a review of the current status of very high energy gamma-ray astronomy. The development of the atmospheric Cherenkov imaging technique for ground-based gamma-ray astronomy has led to a rapid growth in the number of observatories. The detection of TeV gamma rays from Active Galactic Nuclei was unexpected and is providing new insights into the emission mechanisms in the jets. Next generation telescopes are under construction and will increase dramatically the knowle...

  3. Black Stars and Gamma Ray Bursts

    OpenAIRE

    Vachaspati, Tanmay

    2007-01-01

    Stars that are collapsing toward forming a black hole but are frozen near the Schwarzschild horizon are termed ``black stars''. Collisions of black stars, in contrast to black hole collisions, may be sources of gamma ray bursts, whose basic parameters are estimated quite simply and are found to be consistent with observed gamma ray bursts. Black star gamma ray bursts should be preceded by gravitational wave emission similar to that from the coalescence of black holes.

  4. Gamma-Ray Bursts and Particle Astrophysics

    OpenAIRE

    Gendre, B.

    2008-01-01

    Gamma-ray bursts are violent events occurring randomly in the sky. In this review, I will present the fireball model, proposed to explain the phenomenon of gamma-ray bursts. This model has important consequences for the production and observation at Earth of gravitational waves, high energy neutrinos, cosmic rays and high energy photons, and the second part of this review will be focused on these aspects. A last section will briefly discuss the topic of the use of gamma-ray ...

  5. Gamma-Ray Astronomy Technology Needs

    Science.gov (United States)

    Gehrels, N.; Cannizzo, J. K.

    2012-01-01

    In recent decades gamma-ray observations have become a valuable tool for studying the universe. Progress made in diverse 8re1lS such as gamma-ray bursts (GRBs), nucleosynthesis, and active galactic nuclei (AGNs) has complimented and enriched our astrophysical understanding in many ways. We present an overview of current and future planned space y-ray missions and discussion technology needs for- the next generation of space gamma-ray instruments.

  6. Determination of fluorine concentrations in soil samples using proton induced gamma-ray emission

    International Nuclear Information System (INIS)

    A non-destructive, in situ current normalized particle induced gamma-ray emission methodology has been standardized for quantification of fluorine (F) in soil samples from Punjab state, India. The samples were irradiated using 4 MeV proton beam from the Folded Tandem Ion Accelerator at BARC, Mumbai. The gamma rays of energies 197 and 478 keV arising from 19F(p, p'?)19F and 7Li(p, p'?)7Li nuclear reactions were measured using high resolution gamma-ray spectrometry. The concentration of fluorine in soil samples was found to vary between 414 and 5,746 mg kg-1. (author)

  7. Induction of mutation, through gamma rays, in sugarcane

    International Nuclear Information System (INIS)

    Variety buds Co-740 of sugar cane were irradiated with gamma rays 60Co at 0.0, 3.0, 4.0, 5.0, 6.0 and 7.0 kR to study changes in the obtained progeny. Evaluation of the germination capacity, height of plants and morphological changes were studied in the different treatments. (M.A.C.)

  8. Gamma ray induced somatic mutations in rose

    International Nuclear Information System (INIS)

    Budwood of 32 rose cultivars (Rosa spp.) was exposed to 3-4 krad of gamma rays and eyes were grafted on Rosa indica var. odorata root stock. Radiosensitivity with respect to sprouting, survival and plant height, and mutation frequency varied with the cultivar and dose of gamma rays. Somatic mutations in flower colour/shape were detected as chimera in 21 cultivars. The size of the mutant sector varied from a narrow streak on a petal to a whole flower and from a portion of a branch to an entire branch. 14 mutants were detected in M1V1, four in M1V2 and three in M1V3. Maximum number of mutations was detected following 3 krad treatment. Eyes from mutant branches were grafted again on root stock and non-chimeric mutants were aimed at by vegetative propagation. Mutants from 11 cultivars only could be isolated in pure form. Isolation of non-chimeric mutants sometimes is difficult due to weak growth of a mutant branch. In such a case, all normal looking branches are removed to force a better growth of the mutant branch. It is advisable to maintain irradiated plants at least for four years with drastic pruning in each year. Nine mutants viz. 'Sharada', 'Sukumari', 'Tangerine Contempo', 'Yellow Contempo', 'Pink Contempo', 'Striped Contempo', 'Twinkle', 'Curio' and 'Light Pink Prize' have already been released as new cultivars for commercialization [ref. MBNL No. 23 and 31] and others are being multiplied and assessed. The mutation spectrum appears to be wider for the cultivars 'Contempo' and 'Imperator'. Pigment composition of the original variety is relevant for the kind of flower colour mutations that can be induced

  9. Gamma ray emission from pulsars

    International Nuclear Information System (INIS)

    A model for the production of gamma rays in a pulsar environment is presented, together with numerical computations fitted to the observations of PSR 0833-45. It is assumed that the primary particles are accelerated close to the star surface and then injected along the open field lines, which cause them to emit curvature radiation. The equation describing the particles' braking is integrated exactly up to the first order in the pulsar rotational frequency, and the transfer problem for the curvature photons is solved with the aberration, the Doppler shif, and the pair production absorption being taken into account. The latter effect is due not only to the transverse component of the magnetic field, but also to the electric field induced by the rotation. The synchrotron radiation emitted by the secondary particles is also included, subject to the 'on-the-spot' approximation. It is found that the observed gamma rays originate in the innermost regions of the magnetosphere, where the open lines' bundle is narrow and the geometrical beaming is effective. As shown by the computed pulse profiles, the duty cycle turns out to be equal to a few percent, comparable to the one of PSR 0833-45. The averaged spectra indicate that a substantial fraction of the primary photons do outlive the interaction with the magnetisphere; furthermore, the agreement in shape with the observational curves suggests that the acceleration output is fiarly close to a monoenergetic beam of particles. (or to a monoenergetic beam of particles. (orig.)

  10. Magnetars and Gamma Ray Bursts

    CERN Document Server

    Bucciantini, N

    2012-01-01

    In the last few years, evidences for a long-lived and sustained engine in Gamma Ray Bursts (GRBs) have increased the attention to the so called millisecond-magnetar model, as a competitive alternative to the standard collapsar scenario. I will review here the key aspects of the {\\it millisecond magnetar} model for Long Duration Gamma Ray Bursts (LGRBs). I will briefly describe what constraints, present observations put on any engine model, both in term of energetic, outflow properties, and the relation with the associated Supernova (SN). For each of these I will show how the millisecond magnetar model satisfies the requirements, what are the limits of the model, how can it be further tested, and what observations might be used to discriminate against it. I will also discuss numerical results that show the importance of the confinement by the progenitor star in explaining the formation of a collimated outflow, how a detailed model for the evolution of the central engine can be built, and show that a wide varie...

  11. Gamma-ray burst models.

    Science.gov (United States)

    King, Andrew

    2007-05-15

    I consider various possibilities for making gamma-ray bursts, particularly from close binaries. In addition to the much-studied neutron star+neutron star and black hole+neutron star cases usually considered good candidates for short-duration bursts, there are also other possibilities. In particular, neutron star+massive white dwarf has several desirable features. These systems are likely to produce long-duration gamma-ray bursts (GRBs), in some cases definitely without an accompanying supernova, as observed recently. This class of burst would have a strong correlation with star formation and occur close to the host galaxy. However, rare members of the class need not be near star-forming regions and could have any type of host galaxy. Thus, a long-duration burst far from any star-forming region would also be a signature of this class. Estimates based on the existence of a known progenitor suggest that this type of GRB may be quite common, in agreement with the fact that the absence of a supernova can only be established in nearby bursts. PMID:17293332

  12. Caracterización del peuapm irradiado con rayos gamma, almacenado en vitamina e y tratado térmicamente / CHARACTERIZATION OF UHMWPE IRRADIATED WITH GAMMA RAYS, STORED IN E VITAMIN AND THERMALLY TREATED

    Scientific Electronic Library Online (English)

    Ernesto, Davidson; Jacobo, Reyes-Romero; Delfín, Moronta; Gema, González; Othman, Falcón.

    2011-03-01

    Full Text Available La presente investigación tiene como propósito caracterizar el polietileno de ultra alto peso molecular (PEUAPM-Gur- 1050) irradiado a 100 y 50 kGy en atmosfera de argón a 25ºC a una velocidad de 4,8 kGy/h, almacenado en vitamina E a la concentración de 0,1wt% y posterior tratamiento térmico (la mue [...] stra que fue irradiada a 100kGy es la que fue recocida a 120ºC y la que fue irradiada a 50kGy es la que fue refundida a 140ºC), con el fin de mejorar las propiedades para su utilización en ortopedia. Las reacciones de entrecruzamiento fueron las que ocurrieron en mayor grado, siendo este efecto más pronunciado en la muestra que fue refundida a 140ºC. También esta muestra evidenció mayor dureza y resistencia al desgaste, no presentó cambios significativos en los valores de la resistencia a la compresión; en cambio, exhibió una disminución del 10% en el módulo de Young. El análisis mediante FTIR muestra una menor relación de grupos carbonilos en relación con grupos transvinilenos. No se evidenció la presencia de ninguna especie oxidante a través de las espectroscopias de UV cercano y RES. De estos resultados se infiere que el PEUAPM refundida a 140ºC, resultaría el más apropiado para el diseño y fabricación de las prótesis porque contribuiría a que el implante tenga una mayor duración Abstract in english The present investigation has the purpose of characterize the ultra high molecular weight polyethylene (UHMWPE-Gur- 1050), irradiated at 100 and 50 kGy in argon atmosphere at 25ºC, and at a rate of 4.8 kGy/h; After that, they were stored in vitamin E at a concentration of 0.1 wt%. In order to obtain [...] better properties for the use in orthopedics, the samples irradiated at 100 kGy where annealing at 120ºC and the ones at 50 kGy at 140ºC. The crosslinking predominant reactions, in the case of 140ºC remelting temperature, has a greater effect than at 120ºC, showing also greater hardness and resistance to compression, In spite of that they showed a 10% decreasing in the Young module. The FTIR analysis shows a lesser relation of carbonyl groups, related to the transvilidenes groups. It was not found the presence of oxidant species by means of UV and ESR spectroscopy. From the results, can be inferred that the UHMWPE, remelted at 140ºC is more appropriated for the design and manufacturing of prosthesis due to its longer lifespan

  13. Modulating effect of dimethylbenzanthracene on gamma-ray mutagenesis in the soybean test system

    International Nuclear Information System (INIS)

    Dimethylbenzanthracene (DMBA), a strong tumor initiator, did not show mutagenic activity in the soybean test system either alone or in combination with tumor promoter, TPA. In combination treatments with DMBA and gamma-rays, the mutagenicity of gamma-rays was not affected by post-treatment with DMBA. However, DMBA pre-treatment clearly reduced gammaray-ray induced spotting frequency, suggesting that DMBA affects mutagenesis in gamma-irradiated soybean cells

  14. Selección para contenido de proteína del grano en trigo irradiado con rayos gamma de 60Co / Selection for grain protein content in wheat irradiated with 60Co gamma rays

    Scientific Electronic Library Online (English)

    L, Partida-Ruvalcaba; & #932; , Cervantes-Santana; A, Salazar-Zazueta; TJ, Velázquez-Alcaraz.

    2009-12-01

    Full Text Available Esta investigación fue realizada por la necesidad de mejorar las variedades de trigo (Triticum aestivum L.) con alta calidad nutritiva. En compuestos irradiados seleccionados en seis ciclos por mayor tamaño y densidad de grano, se efectuó selección para mayor contenido de proteína. Siete compuestos [...] tuvieron dos niveles de irradiación, difirieron en cinco generaciones de irradiación y 74 kr de dosis acumulada, excepto uno cuya diferencia fue de 73 kr, y procedieron de la variedad 'Salamanca' irradiada con rayos gamma de cobalto sesenta (60Co). La selección fue hecha en plantas M6 y M11, y las líneas seleccionadas fueron evaluadas durante dos ciclos en Montecillo, Estado de México. El contenido de proteína tendió a la normal, con media, intervalo y varianza de 13.1%, 11.6 a 15.8% y 0.45, respectivamente, y 'Salamanca' tuvo 11.5%. Con el segundo nivel de irradiación, la media (13.1%), valor máximo (15.8%), varianza (0.51) y número de líneas (9) con más de 14.6% de proteína, superaron a los del primer nivel, cuyos valores fueron 12.9%, 15.0%, 0.41 y 3. Las tres líneas superiores fueron del segundo nivel de irradiación, con proteína de 14.9 a 15.3%, cuyos mínimo y máximo superaron al contenido de proteína de 'Salamanca' en 19.2 y 22.4%, respectivamente. La correlación de proteína y rendimiento de grano fue negativa (r = -0.59) y altamente significativa; las líneas de alta proteína rindieron menos que 'Salamanca'. Las líneas tuvieron mayor volumen y peso de grano que 'Salamanca', pero casi la misma densidad. Abstract in english This study was conducted in response to the need to improve wheat (Triticum aestivum L.) varieties with a high nutritional quality. A selection for greatest protein content was carried out on irradiated composites selected during six seasons considering a greater grain size and grain density. Seven [...] composites were subjected to two irradiation levels. They differed in five irradiation generations and 74 kr of accumulated doses, except for one with a difference of 73 kr. They came from the Salamanca variety irradiated with gamma rays of cobalt sixty (60Co). The selection was made from M6 and M11 plants, and the selected lines were evaluated over two seasons at Montecillo, State of Mexico. The protein content tended to be normal, with a mean, interval and variance of 13.1%, 11.6 to 15.8% and 0.45, respectively. The 'Salamanca' had 11.5%. With the second irradiation level, the mean (13.1%), maximum value (15.8%), variance (0.51) and number of lines (9) with more than 14.6% protein, exceeded those of the first level, of which the values were 12.9 %, 15.0 %, 0.41 and 3. The three high lines corresponded to the second irradiation level, with protein from 14.9 to 15.3 % and with minimum and maximum values exceeding the protein content of 'Salamanca' by 19.2 and 22.4%, respectively. The protein and grain yield correlation was negative (r = -0.59) and highly significant; the high protein content lines yielded less than 'Salamanca'. The lines had a greater grain volume and weight than 'Salamanca', but almost the same density.

  15. Responses of commercial broiler chicks to 60Co gamma-rays

    International Nuclear Information System (INIS)

    A total of 360 chicks of Nichols line at one-day old were used in this study. Within each sex, the chicks were divided into three exposure treatments (non-irradiated, 400 rads and 800 rads). The source of irradiation was 60Co gamma-rays. The results can be summarized as follows: Of the 360 chicks used in this study, only 10 chicks died during the experimental period. Radiation induced a reduction in body weight in both sexes during the growth period. Gamma-rays reduce the feed intake in both sexes. Moreover, the feed conversion ratio for the irradiated chicks was higher than that the non-irradiated birds. While red blood cells and hemoglobin content were higher in the irradiated chicks, white blood cells count and especially lymphocytes did not affect by 60Co gamma-rays. Gamma-rays had no effect on carcass, bone, meat and giblets as fractions of body weight in both sexes. Moreover, meat water content decreased and meat fat content increased in irradiated chicks. The total length and the total weight of the GI tract decreased due to 60Co gamma-rays. The response of the different regions of the GI tract to this rays is different. Moreover, the effect of this radiation on the GI tract is dependent upon the body weight irrespective of the sex. (orig./MG)

  16. Intercomparison of gamma ray analysis software packages

    International Nuclear Information System (INIS)

    The IAEA undertook an intercomparison exercise to review available software for gamma ray spectra analysis. This document describes the methods used in the intercomparison exercise, characterizes the software packages reviewed and presents the results obtained. Only direct results are given without any recommendation for a particular software or method for gamma ray spectra analysis

  17. GAMMA-400 gamma-ray observatory

    CERN Document Server

    Topchiev, N P; Bonvicini, V; Adriani, O; Aptekar, R L; Arkhangelskaja, I V; Arkhangelskiy, A I; Bakaldin, A V; Bergstrom, L; Berti, E; Bigongiari, G; Bobkov, S G; Boezio, M; Bogomolov, E A; Bonechi, L; Bongi, M; Bottai, S; Castellini, G; Cattaneo, P W; Cumani, P; Dalkarov, O D; Dedenko, G L; De Donato, C; Dogiel, V A; Finetti, N; Gascon, D; Gorbunov, M S; Gusakov, Yu V; Hnatyk, B I; Kadilin, V V; Kaplin, V A; Kaplun, A A; Kheymits, M D; Korepanov, V E; Larsson, J; Leonov, A A; Loginov, V A; Longo, F; Maestro, P; Marrocchesi, P S; Martinez, M; Menshenin, A L; Mikhailov, V V; Mocchiutti, E; Moiseev, A A; Mori, N; Moskalenko, I V; Naumov, P Yu; Papini, P; Paredes, J M; Pearce, M; Picozza, P; Rappoldi, A; Ricciarini, S; Runtso, M F; Ryde, F; Serdin, O V; Sparvoli, R; Spillantini, P; Stozhkov, Yu I; Suchkov, S I; Taraskin, A A; Tavani, M; Tiberio, A; Tyurin, E M; Ulanov, M V; Vacchi, A; Vannuccini, E; Vasilyev, G I; Ward, J E; Yurkin, Yu T; Zampa, N; Zirakashvili, V N; Zverev, V G

    2015-01-01

    The GAMMA-400 gamma-ray telescope with excellent angular and energy resolutions is designed to search for signatures of dark matter in the fluxes of gamma-ray emission and electrons + positrons. Precision investigations of gamma-ray emission from Galactic Center, Crab, Vela, Cygnus, Geminga, and other regions will be performed, as well as diffuse gamma-ray emission, along with measurements of high-energy electron + positron and nuclei fluxes. Furthermore, it will study gamma-ray bursts and gamma-ray emission from the Sun during periods of solar activity. The energy range of GAMMA-400 is expected to be from ~20 MeV up to TeV energies for gamma rays, up to 20 TeV for electrons + positrons, and up to 10E15 eV for cosmic-ray nuclei. For high-energy gamma rays with energy from 10 to 100 GeV, the GAMMA-400 angular resolution improves from 0.1{\\deg} to ~0.01{\\deg} and energy resolution from 3% to ~1%; the proton rejection factor is ~5x10E5. GAMMA-400 will be installed onboard the Russian space observatory.

  18. Supernovae as sources of gamma rays

    Science.gov (United States)

    Burrows, Adam

    1992-01-01

    Most supernovae are profoundly radioactive and the Gamma Ray Observatory is an ideal instrument for detecting their unique gamma ray line and X-ray signatures. How the observation of these hard photons can be used to do supernova science will be addressed, with particular emphasis being placed on Type Ia explosions and nearby events.

  19. Prompt gamma-ray activation analysis (PGAA)

    Energy Technology Data Exchange (ETDEWEB)

    Kern, J. [Fribourg Univ. (Switzerland). Inst. de Physique

    1996-11-01

    The paper deals with a brief description of the principles of prompt gamma-ray activation analysis (PGAA), with the detection of gamma-rays, the PGAA project at SINQ and with the expected performances. 8 figs., 3 tabs., 10 refs.

  20. Processing of complex gamma ray spectra

    International Nuclear Information System (INIS)

    In this paper a general review on analysis of gamma ray spectra is reported. At the same time, practical recommendations on the improvements for general-purpose gamma ray spectrum analysis software as well as for particular applications, are given. The present work at the BARC in this field is presented. (author)

  1. The space gamma-ray observatory AGILE

    International Nuclear Information System (INIS)

    Gamma-rays of cosmic origin are a manifestation of the most energetic phenomena in our Universe. Many astrophysical sources emit gamma-rays including relativistic compact stars, massive black holes in active galactic nuclei, gamma-ray burst sources, and our Sun during intense flares. The mission AGILE (Astro-rivelatore Gamma a Immagini LEggero) is an innovative, cost effective gamma ray mission selected by the Italian Space Agency (ASI) as first payload of the Program for Small Scientific Missions. It is designed to detect and image gamma-ray sources in the energy range 30 MeV-50 GeV and operate as an Observatory open to the international community. Primary scientific goals include the study of AGN's, gamma ray bursts, Galactic sources, unidentified gamma ray sources, solar flares and diffuse gamma ray emission. AGILE is planned to be operational during the years 2002-2005. It will an ideal 'bridge' between EGRET and GLAST, and support space observations and ground based multiwavelength studies of high energy sources

  2. A 16N gamma-ray facility

    Science.gov (United States)

    Hull, Ethan L.; Pehl, Richard H.; Stanley, Michelle R.; Foster, Charles C.; Komisarcik, Kevin; East, Gary W.; Vanderwerp, John D.; Friesel, Dennis L.

    1997-02-01

    A practical 16N gamma-ray source is created in a medium-energy cyclotron environment. A 16N source emits 6129 and 7115 keV gamma rays. The viability of this several ?Ci source for detector calibration and studying detector physics is established.

  3. Interaction between gamma rays and colchicine solution rice variety bengawan

    International Nuclear Information System (INIS)

    Seeds of rice variety Bengawan were radiated by gamma rays of different dosages (from 2.5 to 35 krad with interval of 2.5 krad). Half of each group of irradiated seeds were then treated with a 0.5% of colchicine solution for about 3 hours, 3 days after germination in petridishes. After being washed with distilled water the seedlings were planted in a nursery. One month old plants were then transplanted into polyethylene containers in the greenhouse. The seeds from the M-1 and M-2 plants were then cultivated in the field. Results of statis-tical calculation indicate that there is an interaction bet-ween gamma rays and colchicine solution treatments which affect the plant at dose level of 35 krad. The plant grows more erect, shorter, thicker, and resistent to lodging. (author)

  4. Prompt gamma-ray imaging for small animals

    Science.gov (United States)

    Xu, Libai

    Small animal imaging is recognized as a powerful discovery tool for small animal modeling of human diseases, which is providing an important clue to complete understanding of disease mechanisms and is helping researchers develop and test new treatments. The current small animal imaging techniques include positron emission tomography (PET), single photon emission tomography (SPECT), computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US). A new imaging modality called prompt gamma-ray imaging (PGI) has been identified and investigated primarily by Monte Carlo simulation. Currently it is suggested for use on small animals. This new technique could greatly enhance and extend the present capabilities of PET and SPECT imaging from ingested radioisotopes to the imaging of selected non-radioactive elements, such as Gd, Cd, Hg, and B, and has the great potential to be used in Neutron Cancer Therapy to monitor neutron distribution and neutron-capture agent distribution. This approach consists of irradiating small animals in the thermal neutron beam of a nuclear reactor to produce prompt gamma rays from the elements in the sample by the radiative capture (n, gamma) reaction. These prompt gamma rays are emitted in energies that are characteristic of each element and they are also produced in characteristic coincident chains. After measuring these prompt gamma rays by surrounding spectrometry array, the distribution of each element of interest in the sample is reconstructed from the mapping of each detected signature gamma ray by either electronic collimations or mechanical collimations. In addition, the transmitted neutrons from the beam can be simultaneously used for very sensitive anatomical imaging, which provides the registration for the elemental distributions obtained from PGI. The primary approach is to use Monte Carlo simulation methods either with the specific purpose code CEARCPG, developed at NC State University or with the general purpose codes GEANT4 or MCNP5, to predict results and investigate the feasibility of this new imaging idea. Benchmark experiments have been conducted to test the capability of the code to simulate prompt gamma rays, which are produced by following the nuclear structures of each irradiated isotope, and coincidence counting techniques, which are considered the most important improvement in neutron-related gamma-ray detection applications to reduce gamma background and improve system signal-to-noise ratios. With coincidence prompt gamma rays available, two major imaging techniques, electronic collimations and mechanic collimations, are implemented in the simulation to illustrate the feasibility of imaging elemental distribution by this new technique. The expectation maximization algorithm is employed in electronic collimation to reconstruct images. The common SPECT imaging algorithms are used in mechanical collimation to get an image. Several critical topics concerning practical applications have already been discussed, such as the radiation dose to the mouse and the detection efficiency of high-energy gamma rays. The funding of this work is provided by the Center for Engineering Application of Radioisotopes (CEAR) at North Carolina State University (NCSU) and Nuclear Engineering Education Research.

  5. Effect of gamma-rays on corn grains. Pt. 1

    International Nuclear Information System (INIS)

    In order to study the effect of irradiation of corn grains on the starch extraction and quality of by-products, the grains were subjected to different doses of gamma-rays. It was generally found that irradiation led to increase the water absorption during steeping. This increase in the water absorption increases the yield of starch and facilitates the removal of hulls and germ. However, at higher dose (1,000 Krad) the yield of starch decreses. The results are discussed on the basis of effect of hydrogen bond protein denaturation, and formation of volatile compounds. (orig.)

  6. Hygienizing with gamma rays for the treatment of sewage sludge

    International Nuclear Information System (INIS)

    This method which treats sewage sludge with gamma rays is supported by fundamental knowledge on the effects of ionizing rays on bacteria and parasites. This irradiation treatment neither increases the volume, nor does it release organic nitrogen compounds. The plant (designed for a flow rate of 30 m3/d, source distribution 105Ci60Co, 300 Krad) consists mainly of an irradiation shaft with a built-in central pipe and a circulation system with accessible pump shaft, circulation and suction pumps, block and regulating devices. (orig./HP)

  7. The measurement of gamma ray induced heating in a mixed neutron and gamma ray environment

    International Nuclear Information System (INIS)

    The problem of measuring the gamma heating in a mixed DT neutron and gamma ray environment was explored. A new detector technique was developed to make this measurement. Gamma heating measurements were made in a low-Z assembly irradiated with 14-Mev neutrons and (n, n') gammas produced by a Texas Nuclear Model 9400 neutron generator. Heating measurements were made in the mid-line of the lattice using a proportional counter operating in the Continuously-varied Bias-voltage Acquisition mode. The neutron-induced signal was separated from the gamma-induced signal by exploiting the signal rise-time differences inherent to radiations of different linear energy transfer coefficient, which are observable in a proportional counter. The operating limits of this measurement technique were explored by varying the counter position in the low-Z lattice, hence changing the irradiation spectrum observed. The experiment was modelled numerically to help interpret the measured results. The transport of neutrons and gamma rays in the assembly was modelled using the one- dimensional radiation transport code ANISN/PC. The cross-section set used for these calculations was derived from the ENDF/B-V library using the code MC2-2 for the case of DT neutrons slowing down in a low-Z material. The calculated neutron and gamma spectra in the slab and the relevant mass-stopping powers were used to construct weighting factors which relate the energy deposition in the counter fill-gas to that in the counter wall and in the surrounding material. The gamma energy deposition at various positions in the lattice is estimated by applying these weighting factors to the measured gamma energy deposition in the counter at those locations

  8. Defensive Effects Of Naringenin Against Gamma Rays-Induced Acute Renal Insufficiency In Rats

    International Nuclear Information System (INIS)

    Naringenin; 4,5,7-trihydroxy flavonone (C15H12O5), is a naturally occurring citrus flavonone which has been reported to have a wide range of pharmacological properties. Gamma rays-induced oxidative stresses in kidney tissue were indicated by significant increases of serum urea, creatinine, sodium, chloride and calcium levels as well as renal levels of thiobarbituric acid reactive substances (TBARS) and total nitrate/nitrite (NOx) beside an increase in blood erythrocytes and sedimentation rates (ESR). In contrast, gamma rays induced significant decreases in serum total proteins, albumin, globulin and potassium levels as well as renal level of reduced glutathione (GSH), super oxide dismutase (SOD) and catalase (CAT). Moreover, depletions in total red blood cells (RBC), haemoglobin (Hb), haematocrit (Ht), platelets (Pt), total white blood cells (WBC), lymphocytes, neutrophiles, monocytes and eosinophiles were recorded. The kidney of gamma irradiated rat showed tubular necrosis, degeneration, dilation, desquamation, thickening of basement membrane and luminal cast formation. Naringenin treatment (20 mg/kg/day for 10 days, starting 5 days before gamma rays exposure) markedly attenuated the gamma rays-induced biochemical alterations in serum and renal tissue and alleviated red and white blood indices. Furthermore, naringenin ameliorated the gamma rays-induced pathological changes when compared with gamma irradiated group. These data indicate that the natural dietary antioxidant naringenin might have defensive effects against gamma rays-induced oxidative stress and acute renal insufficiency in rats.

  9. Radiation Treatment of Elastomers

    International Nuclear Information System (INIS)

    The treatment of elastomers by irradiation has been closely linked with the development of radiation chemistry, of which the paper traces the main stages: the pioneering period, fundamental research, studies connected with reactor technology and investigations into radiochemical reactions for industrial purposes. An examination is made of the various processes for radiochemical vulcanization of natural and synthetic rubbers. This examination shows that expensive elastomers, some latex products and binders for rocket propellants have the best industrial potential. Particular emphasis is placed on the leading role which industrialists should play in the future development of these applications. (author)

  10. Controllable gamma-ray sensitivity of Ag-doped and/or AgI-modified Ge-Ga-S glasses

    Energy Technology Data Exchange (ETDEWEB)

    Shen Wei [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Ren Jing, E-mail: jing.ren@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Chen Guorong [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Baccaro, Stefania; Cemmi, Alessia; Di Sarcina, Ilaria; Falconieri, Mauro; Menchini, Francesca [ENEA-UTTMAT, Via Anguillarese 301, 00123 Rome (Italy)

    2012-06-01

    Gamma-ray ({gamma}-ray) sensitivity has been studied in Ag-doped and/or AgI-modified Ge-Ga-S glasses. The sensitivity is controllable in terms of silver presence. Compared to the silver-free sample, the AgI-modified glass shows greater sensitivity to {gamma}-ray irradiation regarding larger change in the transmission spectra ({Delta}T), whereas improved resistance to {gamma}-ray irradiation occurs in the silver-doped AgI-modified glass with only 1 mol% silver metal being intentionally added.

  11. Gamma-ray Astronomy and GLAST

    Science.gov (United States)

    McEnery, Julie

    2007-01-01

    The high energy gamma-ray (30 MeV to 100 GeV) sky has been relatively poorly studied. Most of our current knowledge comes from observations made by the Energetic Gamma Ray Experiment Telescope (EGRET) detector on the Compton Gamma Ray Observatory (CGRO), which revealed that the GeV gamma-ray sky is rich and vibrant. Studies of astrophysical objects at GeV energies are interesting for several reasons: The high energy gamma-rays are often produced by a different physical process than the better studied X-ray and optical emission, thus providing a unique information for understanding these sources. Production of such high-energy photons requires that charged particles are accelerated to equally high energies, or much greater. Thus gamma-ray astronomy is the study of extreme environments, with natural and fundamental connections to cosmic-ray and neutrino astrophysics. The launch of GLAST in 2008 will herald a watershed in our understanding of the high energy gamma-ray sky, providing dramatic improvements in sensitivity, angular resolution and energy range. GLAST will open a new avenue to study our Universe as well as to answer scientific questions EGRET observations have raised. In this talk, I will describe the GLAST instruments and capabilities and highlight some of the science we expect to address.

  12. Studies on overcoming incompatibility of distant hybridization by gamma rays

    International Nuclear Information System (INIS)

    Distant hybridization was carried out after megagametes of hexaploid triticale 'Heizha 266' and androgametes of wheat varieties 'Longfu 30138', 'Longmai 11' and 'Longfu 10271' were irradiated with 60Co gamma rays from 600 to 1600 rad. Through the observation of the pollination in cut sections, it was found that 60-70 percent of embryo sacs were disintegrated 6 hours after pollination. The results of the investigations showed that the rate of fertilization were significantly increased by the irradiation. However, it was decreased with the increase in the dose of the irradiation. The radio-sensitivity of different wheat varieties varies greatly. The optimum dose of the irradiation was 600 rad for megagametes, and 800 rad for androgametes. The rate of survival for hybrid seeds was obviously increased by the treatment of the irradiation. By using tissue culture, some plants could be obtained from hybrids with embryo only

  13. Radiation-Induced Crosslinking of Natural and Synthetic Elastomers in Emulsion or Dispersion

    International Nuclear Information System (INIS)

    The industrial use of the emulsions or dispersions of natural or synthetic elastomers depends on whether they satisfy a certain number of basic criteria. The first aim of the present study was to preserve the factors essential for the industrial production of latex. The second aim was to obtain dry elastomers from radiation-crosslinked latex. These elastomers should have the same basic properties as those obtained in latex vulcanized chemically by the conventional method and their production cost should be competitive. Two methods of irradiation were studied —by 60Co gamma rays and by electrons, using a particle accelerator. The effect of various additives in reducing the irradiation doses needed for a correct crosslinking was studied. Halogen compounds were found to be particularly effective and two of them, chloroform and carbon tetrachloride, made it possible to obtain elastomers with all the desirable characteristics at low irradiation doses. Identical results can be obtained with the addition of polymerizable monomers (vinylic, acrylic etc). Under actual industrial conditions, a strength of 300 kg/cm2 is obtained for films of natural latex which are irradiated to 1 Mrad with electrons and contain small amounts of CCI4. The braking elongation (%) is around 1000*%. Under the same actual conditions, polychlorprene films irradiated to 0.5 Mrad show a tensile strength of 210 kg/cm2. These figures correspond to those obtained by conventional chemical methods. The elasticity obtained is in keeping with the definition according to which a body is said to be elastic if it shows a residual elongation lower than or equal to 5%, after 5 min of percentage elongation equal to half the percentage breaking elongation. The irradiation doses needed at present to obtain such elasticity are uneconomically high. By adding small amounts of elemental sulphur (0.2%) or certain organic thio-derivatives, mixed with adequate amounts of chlorinated additives, it was possible to obtain a residual elongation lower than 5%. It is essential to obtain a sufficient mechanical stability which is constant in time. The same requirement applies to chemical stability and viscosity. As a result of studies on suitable stabilizing agents and methods of mixing additives with latex, it was possible to prepare radiation-cross-linked emulsions satisfying these various requirements. The results relating to ageing show that the presence of anti-oxygen agents is essential. Of the numerous substances tried, 2-2' -methylene bis (4-methyl-6-tertio butyl phenol) was found to be most effective. A natural latex containing 0.75% of this substance, as well as the additives described earlier, after irradiation to 1 Mrad, gives dry elastomer films, whose ageing is comparable to that obtained in conventional vulcanization. (author)

  14. Gamma ray-induced embrittlement of pressure vessel alloys

    International Nuclear Information System (INIS)

    High-energy gamma rays emitted from the core of a nuclear reactor produce displacement damage in the reactor pressure vessel (RPV). The contribution of gamma damage to RPV embrittlement has in the past been largely ignored. However, in certain reactor designs the gamma flux at the RPV is sufficiently large that its contribution to displacement damage can be substantial. For example, gamma rays have been implicated in the accelerated RPV embrittlement observed in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. In the present study, mechanical property changes induced by 10-MeV electron irradiation of a model Fe alloy and an RPV alloy of interest to the HFIR were examined. Mini-tensile specimens were irradiated with high-energy electrons to reproduce damage characteristic of the Compton recoil-electrons induced by gamma bombardment. Substantial increases in yield and ultimate stress were observed in the alloys after irradiation to doses up to 5.3x10-3 dpa at temperatures (?50 degrees C) characteristic of the HFIR pressure vessel. These measured increases were similar to those previously obtained following neutron irradiation, despite the highly disparate nature of the damage generated during electron and neutron irradiation

  15. Gamma ray induced mutants in Gladiolus

    International Nuclear Information System (INIS)

    Effects of gamma rays from 60Co was studied in three varieties of gladiolus, namely, 'Little Giant', 'Mansoer' and 'Wild Rose' irradiated at 1, 2.5, 5, 10 and 15 Krad doses at the Indian Institute of Horticultural Research, Bangalore. Percentage of sprouting was affected significantly at 10 and 15 Krad. LD50 was found to be between 10 and 15 Krad. Doses of 10 Krad and above proved to be detrimental for vegetative and floral traits. Plants treated with 10 Krad did not produce flower spikes, whereas the plants in 15 Krad treatment although sprouted but died afterwards. When treated with 10 Krad, plant height, leaf number and leaf-size were reduced significantly and leaves became narrow and leathery. Flowering was delayed significantly at 5 Krad. Radiation treatments caused decrease in spike length, number of florets per spike and floret size. A desirable and stable mutant with Shell Pink floret colour was isolated from the variety 'Wild Rose' in 1 Krad treament and it has been released as 'Shobha'. (author). 14 refs

  16. HEAO-1 observations of gamma ray bursts

    International Nuclear Information System (INIS)

    A search of data from the High Energy X-Ray and Low Energy Gamma Ray Experiment on HEAO-1 uncovered 14 gamma ray bursts. Nine of these events are reported for the first time. Except for the faintest events, all of the bursts detected by this experiment have been measured above an MeV, thereby confirming the hard spectral character of gamma ray burst spectra reported by SMM. Results give a burst rate of at least 105 per year above 6 times 10 to the minus 7th power ergs, which is consistent with previous measurements of burst frequency

  17. Transmutation by laser Compton gamma-ray

    International Nuclear Information System (INIS)

    Transmutation of nucleon by gamma-ray is reviewed in this articled. We used the NewSUBARU storage ring combined with a small solid state laser to get a laser Compton gamma-ray of energies of 10 to 20 MeV. Reaction rate of nuclear targets of gold and iodine were obtained by simultaneous measurement of neutron and particles. We show a feasibility of energy balance in gamma-ray transmutation cycle system. Future plant system by this method is also addressed. (author)

  18. Interaction effect of gamma rays and thermal neutrons on the inactivation of odontoglossum ringspot virus isolated from orchid

    International Nuclear Information System (INIS)

    The effect of gamma rays or thermal neutrons and their interaction effects on the inactivation of the infectivity of Odontoglossum ringspot virus (ORSV) in buffered crude sap of the plant tissue were studied. The inactivation effect of gamma ray on ORSV varied in different ionic strength of the phosphate buffer solutions. Borax enhanced this effect. In interaction effect of gamma and neutron irradiation, irradiation orders, that is, n ? ? and ? ? n, gave different inactivation pattern. (author)

  19. Fine structure of polyoxymethylene obtained through gamma-ray induced polymerization in solid state

    International Nuclear Information System (INIS)

    The correlation of the infrared spectra for polytrioxane (PTOX) with its polymerization conditions and the gamma-ray irradiation was examined. The infrared spectra were recarded on a EPI-G2 spectrometer in the range from 600 to 1300/cm. The samples were measured in the nujol suspension of polymer powder, which was held between two KBr discs. The total dose of gamma-ray post-irradiation was about 1.4 MR. The spectra taken before and after the gamma-ray irradiation showed strong absorption bands associated with the skeletal vibration of the PTOX chains. The correlation of the superheating with the reduction of the ratio of optical density D-903/D-938 suggests that the long chains associated with the superheating were conformationally distorted in crystallites. (J.P.N.)

  20. Gamma-ray Burst Cosmology

    CERN Document Server

    Wang, F Y; Liang, E W

    2015-01-01

    Gamma-ray bursts (GRBs) are the most luminous electromagnetic explosions in the Universe, which emit up to $8.8\\times10^{54}$ erg isotropic equivalent energy in the hard X-ray band. The high luminosity makes them detectable out to the largest distances yet explored in the Universe. GRBs, as bright beacons in the deep Universe, would be the ideal tool to probe the properties of high-redshift universe: including the cosmic expansion and dark energy, star formation rate, the reionization epoch and the metal enrichment history of the Universe. In this article, we review the luminosity correlations of GRBs, and implications for constraining the cosmological parameters and dark energy. Observations show that the progenitors of long GRBs are massive stars. So it is expected that long GRBs are tracers of star formation rate. We also review the high-redshift star formation rate derived from GRBs, and implications for the cosmic reionization history. The afterglows of GRBs generally have broken power-law spectra, so it...

  1. The AGILE gamma ray satellite

    International Nuclear Information System (INIS)

    AGILE (Light Imager for Gamma-ray Astrophysics) will be launched on an equatorial orbit in 2007 by the PSLV Indian launcher. It is a small scientific satellite for the detection of ?-ray cosmic sources in the energy range 50MeV-30GeV with a field of view of 15 of the sky, and will become the only detector in that energy range till the launch of GLAST. Three different detectors and an anticoincidence system are the components of the scientific instrument. The main detector is a silicon-tungsten tracker. The second detector is a X-ray detector in the range 15-45keV; its main aim is to highlight the X-ray emission associated to the gamma emissions. The third detector is a small calorimeter made of 30CsI scintillating bars read out by photodiodes; its energy range is 150-300keV. The large number of channels (about 37000, with analog read out), requires very reliable components. Each part of the instrument has undergone several tests during the assembly phase; then the whole instrument has been calibrated on a dedicated photon tagged beam-line developed at the DAPHNE BTF (Beam Test Facility, INFN Frascati) and has been integrated with the satellite

  2. Cellular Stress to Low Gamma-ray Dose

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the effect of low gamma ray intensity upon Hsp 70 expression in human lymphocytes. the heat shock proteins (Hsp) family, are a group of proteins present in all living organism, therefore there are highly conserved and are related to adaptation and evolution. At cellular level these proteins acts as chaperones correcting denatured proteins. when a stress agent, such heavy metals, UV, heat, etc. is affecting a cell a response to this aggression is triggered through overexpression of Hsp. Several studies has been carried out in which the cellular effect are observed, mostly of these studies uses large doses, but very few studies are related with low doses. Blood of healthy volunteers was obtained and the lymphocytes were isolated by ficoll-histopaque gradient. Experimental lots were irradiated in a ''137Cs gamma-ray. Hsp70 expression was found since 0.5 cGy, indicating a threshold to very low doses of gamma rays. (Author) 27 refs

  3. Gamma-Ray Astrophysics NSSTC Fermi GBM

    National Aeronautics and Space Administration — The Fermi Gamma-Ray Burst Monitor (GBM) is not a pointed or imaging instrument. To determine fluxes for known sources, we measure the change in the count rate...

  4. The X- and gamma-ray backgrounds

    International Nuclear Information System (INIS)

    The spectrum of the extragalactic X-ray and gamma-ray backgrounds, originating in a redshift of about 3.0, provides a measurement of the integrated X- and gamma-ray evolution of known sources such as clusters of galaxies, active galaxies, and quasars. It also limits possible new classes of sources, such as accreting black holes and a hot intergalactic medium. Attention is given to the contribution to the X- and gamma-ray backgrounds of known evolved and unevolved sources, as well as the character of small scale and large scale fluctuations in the X-ray background. Speculations as to the origin of the X- and gamma-ray background include such possibilities as the inverse Compton scattering of microwave background photons by intergalactic cosmic-ray electrons, accretion of the intergalactic medium onto pregalactic black holes, and matter-antimatter annihilation in a baryon-symmetric universe

  5. Gamma-ray bursts: An overview

    International Nuclear Information System (INIS)

    Gamma Ray Bursts were discovered by researchers studying data from gamma ray detectors aboard the Vela satellites. Since the original discovery, over 500 bursts have been observed by more than a dozen experiments on planetary spacecraft, earth orbiters, balloon flights, and even ground based instruments. Unfortunately, a description of the nature of these transient phenomena is no closer today than two decades ago. Part of the problem lies in the large variability in their physical characteristics. This variability has spawned more than 40 gamma ray burst models. Each model claims some subset of the 500 observed bursts that conclusively proves its validity. A very brief overview is presented of the gamma ray burst phenomenon

  6. Gamma-rays from decaying dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Bertone, G. [Paris-6 Univ., 75 (France). Inst. d' Astrophysique; Buchmueller, W.; Covi, L.; Ibarra, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2007-10-15

    We study the prospects for detecting gamma-rays from decaying Dark Matter (DM), focusing in particular on gravitino DM in R-parity breaking vacua. Given the substantially different angular distribution of the predicted gamma-ray signal with respect to the case of annihilating DM, and the relatively poor (of order 0.1 ) angular resolution of gamma-ray detectors, the best strategy for detection is in this case to look for an exotic contribution to the gamma-ray flux at high galactic latitudes, where the decaying DM contribution would resemble an astrophysical extragalactic component, similar to the one inferred by EGRET observations. Upcoming experiments such as GLAST and AMS-02 may identify this exotic contribution and discriminate it from astrophysical sources, or place significant constraints on the mass and lifetime of DM particles. (orig.)

  7. Combined Neutron and Gamma-Ray Monitor

    International Science & Technology Center (ISTC)

    A Radiation Monitor on the Basis of CdZnTe and NaI(Tl) Gamma-Ray Detectors and Neutron Detectors on Scintillating Fibers for Determining the Characteristics of Radioactive Materials with Localization of Irregularities throughout the Volume

  8. Contribution of External Gamma Rays to SPND at HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Park, B. G.; Cho, D. K.; Kim, M. S.; Kang, G. D. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Self-Powered Neutron Detectors (SPNDs) have been widely used for monitoring the neutron flux in reactors as well as in irradiation facilities. In its simplest form, the detector operates on the basis of directly measuring the beta decay current following neutron capture. The neutron capture cross-section of {sup 103}Rh, which is used for an emitter of the SPND, is 142.13 barns for thermal neutron (0.0253 eV). After neuron capture of {sup 103}Rh, the compound nuclei of {sup 104}Rh (92.6%) and {sup 104}mRh (7.4%) are produced. The sensitivity of SPND is generally defined as. The influence of water in the irradiation basket on the external gamma rays is determined by calculations of neutron capture reaction and photon interaction rates at various irradiation positions in HANARO. Since it is not easy to correct the contribution of the external gamma rays to the current signal by measurements at the research reactor, it is advantageous to reduce materials such as water at the irradiation position.

  9. Gamma ray emission probabilities in 153Sm

    International Nuclear Information System (INIS)

    The use of 153Sm as a therapeutic product requires precise activity standardization and good knowledge of atomic and nuclear decay data in order to calculate as accurately as possible, the internal dose delivered to the patient. In view of this need, several determinations of the absolute gamma ray emission probabilities were reported. In the present work, gamma ray emission probabilities per disintegration of the main line and several other gamma lines were determined using the precisely measured relative gamma intensities

  10. Radio flares from gamma-ray bursts

    OpenAIRE

    Kopac, D.; Mundell, C. G.; Kobayashi, S; Virgili, F. J.; Harrison, R.; Japelj, J.; Guidorzi, C.; Melandri, A.; Gomboc, A

    2015-01-01

    We present predictions of centimeter and millimeter radio emission from reverse shocks in the early afterglows of gamma-ray bursts with the goal of determining their detectability with current and future radio facilities. Using a range of GRB properties, such as peak optical brightness and time, isotropic equivalent gamma-ray energy and redshift, we simulate radio light curves in a framework generalized for any circumburst medium structure and including a parametrization of ...

  11. Magic gamma rays, extra-atmospheric source

    International Nuclear Information System (INIS)

    Without the atmospheric layer, the cosmos radiation would kill every living, our planet would be like the moon. The cosmic gamma ray to collide with gases in land cover, as it is disintegrated. They are harmless, they form a cone of light that points to the cosmic source comes from. On April 25, 2009 was born on the island of Palma Magic II and Magic I the best observer of atmospheric gamma rays of low intensity. (Author)

  12. Application of Laser Compton Scattered gamma-ray beams to nondestructive detection and assay of nuclear material

    International Nuclear Information System (INIS)

    Generation of energy-tunable gamma-rays via Laser Compton Scattering (LCS) is of great interest for scientific studies and applications of MeV photons which interact with nuclei. One of the promising applications of such energy-tunable gamma-rays is the non-destructive detection and assay of nuclides which are necessary for nuclear security and safeguards. Utilizing this LCS gamma-ray beam in combination with nuclear resonant fluorescence (NRF), we can make non-destructive measurement of arbitrary nuclides. The principle of LCS-NRF is as follows. When a nucleus is irradiated by a gamma-ray and when the energy of the gamma ray is identical to the transition energy from the ground state of the nucleus, the incident gamma-ray is absorbed by the nucleus, and subsequently the nucleus de-excites by gamma-ray emission. Since the energies of the state excited by NRF are inherent in the atomic number and mass of the nucleus of interest, detection and assay of nuclides are possible by NRF measurement. The ability of gamma-ray beams to penetrate a sample enables us to detect or assay specific nuclides even inside a sample. We are developing a high-flux and a high-brightness gamma-ray source based on an energy-recovery linac and a laser enhancement cavity to produce a gamma-ray beam of 1013 ph/s. Gamma-ray measurement methods optimized for highly radioactive samples are also under development. (A.C.)

  13. The HAWC Gamma-Ray Observatory: Sensitivity to Steady and Transient Sources of Gamma Rays

    CERN Document Server

    Abeysekara, A U; Alvarez, C; Álvarez, J D; Arceo, R; Arteaga-Velázquez, J C; Solares, H A Ayala; Barber, A S; Baughman, B M; Bautista-Elivar, N; Belmont, E; BenZvi, S Y; Berley, D; Rosales, M Bonilla; Braun, J; Caballero-Lopez, R A; Caballero-Mora, K S; Carramiñana, A; Castillo, M; Cotti, U; Cotzomi, J; de la Fuente, E; De León, C; DeYoung, T; Hernandez, R Diaz; Díaz-Vélez, J C; Dingus, B L; DuVernois, M A; Ellsworth, R W; Fernandez, A; Fiorino, D W; Fraija, N; Galindo, A; Garfias, F; González, L X; González, M M; Goodman, J A; Grabski, V; Gussert, M; Hampel-Arias, Z; Hui, C M; Hüntemeyer, P; Imran, A; Iriarte, A; Karn, P; Kieda, D; Kunde, G J; Lara, A; Lauer, R J; Lee, W H; Lennarz, D; Vargas, H León; Linares, E C; Linnemann, J T; Longo, M; Luna-GarcIa, R; Marinelli, A; Martinez, H; Martinez, O; Martínez-Castro, J; Matthews, J A J; Miranda-Romagnoli, P; Moreno, E; Mostafá, M; Nava, J; Nellen, L; Newbold, M; Noriega-Papaqui, R; Oceguera-Becerra, T; Patricelli, B; Pelayo, R; Pérez-Pérez, E G; Pretz, J; Rivière, C; Rosa-González, D; Salazar, H; Salesa, F; Sanchez, F E; Sandoval, A; Santos, E; Schneider, M; Silich, S; Sinnis, G; Smith, A J; Sparks, K; Springer, R W; Taboada, I; Toale, P A; Tollefson, K; Torres, I; Ukwatta, T N; Villaseñor, L; Weisgarber, T; Westerhoff, S; Wisher, I G; Wood, J; Yodh, G B; Younk, P W; Zaborov, D; Zepeda, A; Zhou, H

    2013-01-01

    The High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory is designed to record air showers produced by cosmic rays and gamma rays between 100 GeV and 100 TeV. Because of its large field of view and high livetime, HAWC is well-suited to measure gamma rays from extended sources, diffuse emission, and transient sources. We describe the sensitivity of HAWC to emission from the extended Cygnus region as well as other types of galactic diffuse emission; searches for flares from gamma-ray bursts and active galactic nuclei; and the first measurement of the Crab Nebula with HAWC-30.

  14. Physiological and biochemical effects of gamma ray of tomato fruits

    International Nuclear Information System (INIS)

    The effects of gamma ray on the respiration rate of whole fruits, tissues and mitochondria of tomatoes were determined with the presence of KCN, SHAM and DNP. The CO2 production increased with irradiation doses immediately after exposure. However fruits treated with 2.5 kGy and above did not show any climateric peak in respiration. KCN adversely stimulated the O2 consumption by slices of irradiated sample which was prevented when both KCN and SHAM were added together. The DNP effects were not affected by irradiation treatment. The ability of mitochondria of irradiated sample to oxidize succinate was not affected by KCN alone but restricted when both KCN and SHAM were present. (author)

  15. Gamma-ray Albedo of the Moon

    Energy Technology Data Exchange (ETDEWEB)

    Moskalenko, Igor V.; Porter, Troy A.

    2007-06-14

    We use the GEANT4 Monte Carlo framework to calculate the gamma-ray albedo of the Moon due to interactions of cosmic ray (CR) nuclei with moon rock. Our calculation of the albedo spectrum agrees with the EGRET data. We show that the spectrum of gamma-rays from the Moon is very steep with an effective cutoff around 3 GeV (600 MeV for the inner part of the Moon disc). Since it is the only (almost) black spot in the gamma-ray sky, it provides a unique opportunity for calibration of gamma-ray telescopes, such as the forthcoming Gamma Ray Large Area Space Telescope (GLAST). The albedo flux depends on the incident CR spectrum which changes over the solar cycle. Therefore, it is possible to monitor the CR spectrum using the albedo gamma-ray flux. Simultaneous measurements of CR proton and helium spectra by the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA), and observations of the albedo -rays by the GLAST Large Area Telescope (LAT), can be used to test the model predictions and will enable the GLAST LAT to monitor the CR spectrum near the Earth beyond the lifetime of PAMELA.

  16. Gamma-ray- and fission-neutron-induced micronuclei in PHA-stimulated and unstimulated human lymphocytes

    International Nuclear Information System (INIS)

    Two groups of normal human an blood cells, one stimulated with phytohaemagglutinin (PHA) for 24 hr (G1-S phase of the cell cycle) and one unstimulated (G0 phase), were irradiated with 60Co gamma rays or 252Cf radiation. A comparison of radiation-induced micronucleus frequencies showed that the high-dose-rate gamma rays were more effective in inducing micronuclei than were low-dose-rate gamma rays. In the cells exposed to low-dose-rate irradiation, there was little difference between the frequency of micronuclei in the G0 phase and the G1-S phase. However, cells in the G1-S phase were more sensitive than G0-phase cells to high-dose-rate gamma rays. The relative biological effectiveness of 252Cf neutron irradiation measured in micronucleus assays was consistent with the value obtained for the lethal effect of 252Cf on cultured cells. (author)

  17. Neutron-induced gamma-ray spectroscopy: simulations for chemical mapping of planetary surfaces

    International Nuclear Information System (INIS)

    Cosmic rays interact with the surface of a planetary body and produce a cascade of secondary particles, such as neutrons. Neutron-induced scattering and capture reactions play an important role in the production of discrete gamma-ray lines that can be measured by a gamma-ray spectrometer on board of an orbiting spacecraft. These data can be used to determine the concentration of many elements in the surface of a planetary body, which provides clues to its bulk composition and in turn to its origin and evolution. To investigate the gamma rays made by neutron interactions, thin targets were irradiated with neutrons having energies from 14 MeV to 0.025 eV. By means of foil activation technique the ratio of epithermal to thermal neutrons was determined to be similar to that in the Moon. Gamma rays emitted by the targets and the surrounding material were detected by a high-resolution germanium detector in the energy range of 0.1 to 8 MeV. Most of the gamma-ray lines that are expected to be used for planetary gamma-ray spectroscopy were found in the recorded spectra and the principal lines in these spectra are presented. 58 refs., 7 figs., 9 tabs

  18. Effect of gamma-ray on olive fruits quality, enzyme activities and issued oil

    International Nuclear Information System (INIS)

    The results described in the present work concern the study of changes in gamma ray irradiated olive fruit (Tunisian variety: Chemlali) quality along the storage time processing and the quality of olive oil issued. The study focused on the changes related to the microbiological, physico-chemical properties, as well as pectinase activities in olive after irradiation. We also have been interested in the final product quality after oil extraction. The results of non irradiated olives were presented for comparative purposes. Mature olive fruits were treated with 0.5, 1 and 1.5 kGy gamma ray radiation. Olive fruits were then stored for one month. Irradiation at 1.5 kGy allows the almost total destruction of the total aerobic germs, yeasts and moulds. Concerning physico-chemical parameters, the increase of the dose level generated an improvement in water retention capacity and decreased the rate of polysaccharides hydrolyzes olives. Moreover, the irradiation dose of 0.5 kGy induced the increase in pectinase activities thanks to the improvement of the protein extraction yield. The gamma ray irradiation of olive fruit seems to not decrease olive oil oxidative stability in the studied samples. Finally, gamma ray radiation was able to improve the yield of extraction of the oil and insaponifiable fraction as polyphenols and beta carotenes. (Author)

  19. Historical aspects of gamma-ray astronomy

    Science.gov (United States)

    Sreekantan, B. V.

    2002-03-01

    Over the entire 20th century, Cosmic Rays proved to be the watershed of fundamental knowledge from which poured out several streams that made us familiar with aspects of the universe that could never have been known through optical and radio astronomies alone. Cosmic ray interaction studies opened up the field of elementary particles and high energy physical processes. Gamma-ray astronomy enabled us to study celestial environments characterised by the dominance of high energy particles and their interactions with matter, magnetic and electric fields in the neighbourhood of these special environments. While neutrino astronomy is still in its infancy, it has the potential of becoming the most exciting field of study in the current century. Gamma-ray astronomy has had a chequered career. In the early part of the 20th century, Millikan proposed that cosmic rays are merely gamma rays. This was disproved by Compton, through the establishment of the latitude effect. The soviet astrophysicist Shklovskii pointed out at the III International conference on cosmic rays held at Guanjuato, Mexico, the possibility of supernova remants like the Crab Nebula being sources of TeV gamma rays. This was based on his realisation that the high degree of polarized light from the Crab could be due to Synchrotron emission by TeV energy electrons spiralling round the filamentary magnetic fields of the nebula. He argued that the same mechanism that accelerated electrons could also accelerate the protons which through their interaction with the surrounding matter generate pi-zero measons that would immediately decay into gamma rays. However, the efforts by the soviet experimentalists, who used the night air cerenkov technique for detection of the TeV gamma rays, proved negative; only upper limits could be set on the fluxew of TeV gamma rays from several of the SN-remnants; the negative results were first reported at the 7th ICRC held at Jaipur, India in 1963. High energy gamma ray astronomy had a remarkable revival with the discovery of Pulsars in 1967 and their identification with Neutron stars. The field has thrived since then has been extended even to the PeV range. Beginning with 1965, gamma ray astronomy in the energy range MeV to tens of GeV has also been successfully pursued with ballons, and satellites. The most perplexing in this energy range has been the discovery of the Gamma ray bursts. In the keynote address the historical aspects of this field will be covered with some references to the work in India.

  20. Fireball/Blastwave Model and Soft Gamma-ray Repeaters

    OpenAIRE

    Huang, Y. F.; Dai, Z. G.; Lu, T.

    1998-01-01

    Soft gamma-ray repeaters are at determined distances and their positions are known accurately. If observed, afterglows from their soft gamma-ray bursts will provide important clues to the study of the so called "classical gamma-ray bursts". On applying the popular fireball/blastwave model of classical gamma-ray bursts to soft gamma-ray repeaters, it is found that their X-ray and optical afterglows are detectable. Monitoring of the three repeaters is solicited.