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Sample records for 60co gamma rays

  1. Different gamma ray (60 Co) dose effects on Sorghum genotype germination

    International Nuclear Information System (INIS)

    In agriculture, applying irradiation is a very valuable way of obtaining vegetable products for human and animal consumption. Cobalt-60, one of the main sources of gamma-rays, is considered an important tool in plant breeding programs, which have the objective of promoting genetic variability of cultivars with resistance to adverse environments. In this research, the effects of different 60Co doses on germination vigor and seed germination velocity of forage sorghum genotypes were evaluated. The study was carried out at the IPA (Empresa Pernambucana de Pesquisa Agropecuaria) in Recife, Pernambuco, Brazil. The work was installed in germination boxes, following laboratory recommendations. Thus, a experiment involving three sorghum genotypes (IPA 467-4-2, IPA 02-03-01, and Sudan 4202), five 60Co doses (Zero, 150, 300, 350, and 400 Gy), was set up. The sees were irradiated before the beginning of the experiment being exposed to gamma rays from a 60Co-source (cobalt irradiator) at DEN (Nuclear Engineering Department) of the UFPE (Pernambuco Federal University), Brazil. The work also had the objective of evaluating the sorghum genotypes x 60Co dose interaction. The main results obtained showed that the sorghum genotype IPA 02-03-01 presented the greatest values of germination and vigor percentages, and seed germination velocity, when compared to the others evaluated, on 350 and 400 Gy of 60Co doses. (author)

  2. Dosimetric response of united, commercially available CTA foils for 60Co gamma rays

    International Nuclear Information System (INIS)

    The usefulness of two kinds of untinted CTA foils: Fuji CTR-125 dosimetric foil and technical CTA-T foil, produced by 'Zaklady Chemiczne, 'Gorzow Wielkopolski' as support for light-sensitive layers of amateur photo-films, for 60Co gamma ray dosimetry was investigated. In spite of rather bad physical parameters of the technical foil (spread of foil thickness, high and different initial absorbance) the dosimetric response of both foils for 60Co gamma rays was similar. The CTA-T foil can be used for routine dosimetry providing that dosimetric signals have to be calculated exactly as recommended by the ASTM (American Society for Testing and Materials) standard, i.e. as the difference of absorbance of irradiated and (the same) non-irradiated foil. Any other approach may lead to high errors of dose evaluation. The last is true also for other CTA foils, especially after long self-life. (author)

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

    Institute of Scientific and Technical Information of China (English)

    HE Sao-Ping; YAO Zhi-Bin; ZHANG Feng-Qi

    2009-01-01

    Radiation hardened CC4007RH and non-radiation hardened CC4011 devices were irradiated using 80Co gamma rays, 1 MeV electrons and 1--9 MeV protons to compare the ionizing radiation damage of the gamma rays with the charged particles. For all devices examined, with experimental uncertainty, the radiation induced threshold voltage shifts (△Vth) generated by 60Co gamma rays are equal to that of 1 MeV electron and 1-7 MeV proton radiation under 0 gate bias condition. Under 5 V gate bias condition, the distinction of threshold voltage shifts (△Vth) generated by 60Co gamma rays and 1 MeV electrons irradiation are not large, and the radiation damage for protons below 9 MeV is always less than that of 60Co gamma rays. The lower energy the proton has, the less serious the radiation damage becomes.

  4. 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)

  5. The radiation effect of 60Co gamma rays on polycarbonate detector

    International Nuclear Information System (INIS)

    The irradiation of polymeric materials with ionizing radiation (gamma rays, X rays, accelerated electrons, ion beams) leads to the formation of very reactive intermediates products (excited states, ions and free radicals), which result in rearrangements and/or formation of new bonds. The effects of these reactions are formation of oxidized products, grafts, scission of main chain (degradation) or cross-linking. Often the two processes (degradation - cross- linking) occur simultaneously, and the outcome of the process is determined by a competition between the reactions. Polycarbonate detectors are used as a particle track detector for neutrons and alpha particles detection. This work aims to study the ionizing radiation dose response of polycarbonate samples using spectrophotometric technique. A commercially available polycarbonate was analysed and its dosimetric characteristics were studied: radiation-induced absorption spectra, ambient light, temperature and humidity influence, pre- and post-irradiation stability, reproducibility and dose range useful response. Samples of polycarbonate (3 x 1 cm2) were irradiated with 60Co gamma radiation in free air at electronic equilibrium with absorbed doses between 1 and 95 kGy. When exposed to gamma radiation the polycarbonate detectors undergoes changes in their optical response, the colour variation is used for determining the absorbed dose. A Shimadzu UV-2101PC spectrophotometer was used for scanning the absorption spectra and measuring the optical density of film detectors irradiated with different radiation doses. Polycarbonate film detector are easy to prepare and to analyse, of good optical quality, inexpensive and of small size. The dosimetric accuracy can be affect by environmental conditions so, the detectors must be stored in appropriate conditions. The reproducibility of the detectors response can be improved by careful monitoring of optical densities before irradiation. The dose response curve presents linear

  6. Biochemical and pharmacological characterization of irradiated crotamine by gamma rays of 60Co

    International Nuclear Information System (INIS)

    The serum production in Brazil, the only effective treatment in cases of snakebites, uses horses that although large size, have reduced l lifespan compared with horses not immunized. Ionizing radiation has been shown as an excellent tool in reducing the toxicity of venoms and toxins isolated, and promote the achievement of better immunogens for serum production, and contributing to the welfare of serum-producing animals. It is known, however, that the effects of ionizing radiation on protein are characterized by various chemical modifications, such as fragmentation, cross-linking due to aggregation and oxidation products generated by water radiolysis. However, the action of gamma radiation on toxins is not yet fully understood structurally and pharmacologically, a fact that prevents the application of this methodology in the serum production process. So we proposed in this paper the characterization of crotamine, an important protein from the venom of Crotalus durissus terrificus species, irradiated with 60Co gamma rays. After isolating the toxin by chromatographic techniques and testing to prove the obtaining of pure crotamine, it was irradiated with gamma rays and subjected to structural analysis, Fluorescence and Circular Dichroism. Using high hydrostatic pressure tests were also conducted in order to verify that the conformational changes caused by radiation suffer modifications under high pressures. From the pharmacological point of view, muscle contraction tests were conducted with the objective of limiting the action of crotamine in smooth muscle as well as the change in the action of toxin caused structural changes to the front. Analysis of Circular Dichroism and Fluorescence showed changes in structural conformation of crotamine when subjected to gamma radiation and that such changes possibly occurring in the secondary and tertiary structure of the protein. The observed in pharmacological tests showed that the irradiated crotamine was less effective in

  7. Effect of 60Co gamma-ray irradiation on dilute aqueous solutions of surfactants

    International Nuclear Information System (INIS)

    Present work deals with the effects of gamma irradiation from 60Co γ-ray source upon aqueous solutions of three kinds of surfactants. When dilute aqueous solutions of sodium dodecyl sulfate (SDS, anionic), cethyl trimethyl ammonium chloride (CTAC, cationic), and polyoxyethylene lauryl ether (POE, non-ionic) were irradiated with γ-rays at a room temperature, the residual concentration, products, surface tension, and forming power were examined by colorimetric method, IR spectrophotometric method, gaschromatography, Ross-Miles method, and Traube's stalagmometer etc. These surfactants were decomposed by the irradiation and thus the surface tension increased and the forming power, on the contrary, decreased with dose. Radiation chemical yields (G-value) of the degradation were about 1 for the solutions of SDS and CTAC, and about 0.3 for the POE solution. From the experimental results, it was found that following chemical reactions seem to occur followed by the radiolysis of water: a) bond cleavage of ester for SDS, of CN for CTAC, and of oxyethylene for POE, b) hydrogen abstraction from the surfactants, c) production of CO bond in the presence of dissolved oxygen. (auth.)

  8. 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)

  9. Changes in membrane receptors of B and T human lymphocytes exposed to 60Co gamma rays

    International Nuclear Information System (INIS)

    The present report describes the effect of 50 to 2500 rad of 60Co gamma rays on the membrane receptors of B and T lymphocytes. Surface membrane immunoglobulins and Fc receptors were used as markers for B cells, while the formation of rosettes with sheep red blood cells was used as a marker for T cells. The effect of radiation is expressed as the percentage of viable cells that bear membrane receptors. The radiation effects were studied after 2, 24, 36 hr of culture. For B lymphocytes no reduction in SmIg and Fc receptors was seen 2 hr after radiation, whereas a dose-related reduction was observed after 24 and 36 hr. A dose-related inhibition of the ''capping'' of SmIg was observed. For T lymphocytes a reduction of E rosette formation was seen starting 2 hr after irradiation. Electron microscopy of separated B and T cells showed a higher sensitivity of T cells as well as a different structural arrangement of the chromatin as a consequence of radiation damage. These data suggest differentiated behavior of B and T lymphocyte membrane receptors after exposure to radiation

  10. 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)

  11. Biochemical and pharmacological characterization of irradiated crotamine by gamma rays of {sup 60}Co; Caracterizacao bioquimica e farmacologica da crotamina irradiada por raios gama de {sup 60}Co

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Karina Corleto

    2014-07-01

    The serum production in Brazil, the only effective treatment in cases of snakebites, uses horses that although large size, have reduced l lifespan compared with horses not immunized. Ionizing radiation has been shown as an excellent tool in reducing the toxicity of venoms and toxins isolated, and promote the achievement of better immunogens for serum production, and contributing to the welfare of serum-producing animals. It is known, however, that the effects of ionizing radiation on protein are characterized by various chemical modifications, such as fragmentation, cross-linking due to aggregation and oxidation products generated by water radiolysis. However, the action of gamma radiation on toxins is not yet fully understood structurally and pharmacologically, a fact that prevents the application of this methodology in the serum production process. So we proposed in this paper the characterization of crotamine, an important protein from the venom of Crotalus durissus terrificus species, irradiated with {sup 60}Co gamma rays. After isolating the toxin by chromatographic techniques and testing to prove the obtaining of pure crotamine, it was irradiated with gamma rays and subjected to structural analysis, Fluorescence and Circular Dichroism. Using high hydrostatic pressure tests were also conducted in order to verify that the conformational changes caused by radiation suffer modifications under high pressures. From the pharmacological point of view, muscle contraction tests were conducted with the objective of limiting the action of crotamine in smooth muscle as well as the change in the action of toxin caused structural changes to the front. Analysis of Circular Dichroism and Fluorescence showed changes in structural conformation of crotamine when subjected to gamma radiation and that such changes possibly occurring in the secondary and tertiary structure of the protein. The observed in pharmacological tests showed that the irradiated crotamine was less effective

  12. Effects of 60Co gamma-rays, ultraviolet light, and mitomycin C on Halobacterium salinarium and Thiobacillus intermedius.

    Science.gov (United States)

    Shahmohammadi, H R; Asgarani, E; Terato, H; Ide, H; Yamamoto, O

    1997-03-01

    Lethal effects of 60Co gamma-rays, UV light, and mitomycin C on two kinds of bacteria, Halobacterium salinarium which grows in highly concentrated salt media and Thiobacillus intermedius which requires reduced sulfur compounds, were studied and compared with those on Escherichia coli B/r. D37 values for H. salinarium, T. intermedius and E. coli B/r were 393, 150, and 92 Gy, respectively, by exposure to 60Co gamma-rays. They were 212, 38, and 10 J/m2, respectively, by exposure to UV light and 2.36, 0.25, and 0.53 microgram/ml/h, respectively, by exposure to mitomycin C. Against these agents, H. salinarium was much more resistant than T. intermedius and E. coli B/r.

  13. Effects of {sup 60}Co gamma-rays, ultraviolet light, and mitomycin C on halobacterium salinarium and thiobacillus intermedius

    Energy Technology Data Exchange (ETDEWEB)

    Shahmohammadi, H.R.; Asgarani, E.; Terato, Hiroaki; Ide, Hiroshi; Yamamoto, Osamu [Hiroshima Univ. (Japan)

    1997-03-01

    Lethal effects of {sup 60}Co {gamma}-rays, UV light, and mitomycin C on two kinds of bacteria, Halobacterium salinarium which grows in highly concentrated salt media and Thiobacillus intermedius which requires reduced sulfur compounds, were studied and compared with those on Escherichia coli B/r. D{sub 37} values for H. salinarium, T. intermedius and E. coli B/r were 393, 150, and 92 Gy, respectively, by exposure to {sup 60}Co {gamma}-rays. They were 212, 38, and 10 J/m{sup 2}, respectively, by exposure to UV light and 2.36, 0.25, and 0.53 {mu}g/ml/h, respectively, by exposure to mitomycin C. Against these agents, H salinarium was much more resistant than T. intermedius and E. coli B/r. (author)

  14. Multistep process of neoplastic transformation of normal human fibroblasts by 60Co gamma rays and Harvey sarcoma viruses

    Energy Technology Data Exchange (ETDEWEB)

    Namba, M.; Nishitani, K.; Fukushima, F.; Kimoto, T.; Nose, K.

    1986-03-15

    As reported previously (Namba et al., 1985), normal human fibroblasts were transformed by 60Co gamma-ray irradiation into immortal cells with abnormal karyotypes. These transformed cells (KMST-6), however, showed a low cloning efficiency in soft agar and no transplantability. However, upon treatment with Harvey murine sarcoma virus (Ha-MSV), the cells acquired elevated clonability in soft agar and transplantability in nude mice. Ha-MSV alone, however, did not convert normal human fibroblasts into either immortal or tumorigenic cells. The Ha-MSV-transformed KMST-6 cells showed an enhanced expression of the ras oncogene, but normal and 60Co gamma-ray-transformed cells did not. Our current data suggest that gamma rays worked against normal human cells as an initiator, giving rise to chromosome aberrations and immortality, and that Ha-MSV, probably through its ras oncogene, played a role in the progression of the malignant cell population to a more malignant one showing enhanced colony formation in soft agar and tumorigenicity in nude mice.

  15. Irradiation effect on enzymatic activity of papain with {sup 60}Co-{gamma} rays

    Energy Technology Data Exchange (ETDEWEB)

    Furuta, Masakazu; Ohashi, Isao; Oka, Masahito; Hayashi, Toshio [Osaka Prefecture Univ., Sakai (Japan). Research Inst. for Advanced Science and Technology

    1998-12-31

    An investigation was made on the durability of enzyme activity against {sup 60}Co-{gamma} irradiation at a dose up to 55 kGy/h using dry powder and aqueous solution of papain preparations on the market. Hybrid materials including bioactive molecules combined with biocompatible synthetic polymers are expected to have biocompatible properties and also biomimetic functions as a component of artificial organs for human body. The activity of papain in an aqueous solution was rapidly decreased at the early stage of irradiation through oxidation of SH group at its active site with active oxygen produced by the irradiation and then, partially recovered since SH group was reproduced in an anoxic state after O{sub 2} consumption in the solution irradiated at a high dose. A usual radiation method for sterilization was found applicable to decontamination of dry and frozen preparations of papain. When suitable conditions for radiation were chosen and N{sub 2} gas was purged to suppress the formation of free radicals, it was possible to keep the enzyme activity at more than 50% of the initial activity after radiation at 30 kGy. (M.N.)

  16. Chemical changes in the chloroform-paraffin system irradiated by 60Co gamma-rays, 1

    International Nuclear Information System (INIS)

    It has been reported that the chloroform-paraffin-dye system have excellent sensitivity for radiation as a solid chemical dosimeter or a phantom. However, the chemical changes in the irradiated system are not examined in detail. In the present study, the effect of paraffin on changes in the above system of a liquid state irradiated by 60Co γ-rays was examined by using various normal paraffin, and the other variable factors on the changes were done. When the chloroform solution and the solution containing 25 per cent of paraffin by volume with 5.0 x 15-5 mol/liter of Methyl Yellow as a dye were irradiated by 2000 R, G values for the formation of hydrogen chloride in the both solutions were 8.4 and 10.8, respectively, and were little affected by the kind of those, from C6 (hexane) to C36 (hexatria-contane). These results suggest that chlorine radical formed by radiolysis of chloroform may react with hydrogen atom from paraffin, thereby increasing the amount of hydrogen chloride. Presence of oxygen increased G value of the chloroform solution from 7.6 to 8.4, but did little that of the solution containing paraffin. (author)

  17. Determination of late-time Gamma-Ray (60Co) sensitivity of single diffusion Lot 2N2222A transistors.

    Energy Technology Data Exchange (ETDEWEB)

    DePriest, Kendall Russell; Kajder, Karen C.; Peters, Curtis D. (American Staff Augmentation Providers, LLC, Albuquerque, NM)

    2008-08-01

    Sandia National Laboratories (SNL) has embarked on a program to develop a methodology to use damage relations techniques (alternative experimental facilities, modeling, and simulation) to understand the time-dependent effects in transistors (and integrated circuits) caused by neutron irradiations in the Sandia Pulse Reactor-III (SPR-III) facility. The development of these damage equivalence techniques is necessary since SPR-III was shutdown in late 2006. As part of this effort, the late time {gamma}-ray sensitivity of a single diffusion lot of 2N2222A transistors has been characterized using one of the {sup 60}Co irradiation cells at the SNL Gamma Irradiation Facility (GIF). This report summarizes the results of the experiments performed at the GIF.

  18. An investigation on the radiation sensitivity of DNA conformations to 60Co gamma rays by using Geant4 toolkit

    International Nuclear Information System (INIS)

    To investigate the impact of conformational properties of genetic material of living cells on radiation-induced DNA damage, single strand breaks (SSB), double strand breaks (DSB) and some microdosimetric quantities of A, B and Z-DNA conformations caused by 60Co gamma rays, have been calculated. Based on a previous B-DNA geometrical model, models of A and Z forms have been developed. Simple 34 base pairs segments of each model repeated in high number and secondary electron spectrum of 60Co gamma rays have been simulated in a volume of a typical animal cell nucleus. All simulations in this study have been performed by using the Geant4 (GEometry ANd Tracking 4)-DNA extension of the Geant4 toolkit. The results showed that, B-DNA has the lowest yield of simple strand breaks with 2.23 × 10−10 Gy−1 Da−1 and 1.0 × 10−11 Gy−1 Da−1 for the SSB and DSB damage yield, respectively. The A-DNA has the highest SSB yield with 3.59 × 10−10 Gy−1 Da−1 and the Z-DNA has the highest DSB yields with 1.8 × 10−11 Gy−1 Da−1. It has been concluded that there is a direct correlation between the hit probability, mean specific imparted energy and SSB yield in each model of DNA. Moreover, there is a direct correlation between the DSB yield and both the mean lineal energy and topological characteristics of each model

  19. An investigation on the radiation sensitivity of DNA conformations to {sup 60}Co gamma rays by using Geant4 toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Semsarha, F. [Institute of Biochemistry and Biophysics (IBB), University of Tehran, P.O. Box 13145-1384, Tehran (Iran, Islamic Republic of); Goliaei, B., E-mail: goliaei@ibb.ut.ac.ir [Institute of Biochemistry and Biophysics (IBB), University of Tehran, P.O. Box 13145-1384, Tehran (Iran, Islamic Republic of); Raisali, G.; Khalafi, H. [Radiation Applications Research School, Nuclear Science and Technology Research Institute, P.O. Box 11365-3486, Tehran (Iran, Islamic Republic of); Mirzakhanian, L. [Medical Physics Unit, McGill University, 1650 Cedar Avenue, Montreal, Quebec (Canada)

    2014-03-15

    To investigate the impact of conformational properties of genetic material of living cells on radiation-induced DNA damage, single strand breaks (SSB), double strand breaks (DSB) and some microdosimetric quantities of A, B and Z-DNA conformations caused by {sup 60}Co gamma rays, have been calculated. Based on a previous B-DNA geometrical model, models of A and Z forms have been developed. Simple 34 base pairs segments of each model repeated in high number and secondary electron spectrum of {sup 60}Co gamma rays have been simulated in a volume of a typical animal cell nucleus. All simulations in this study have been performed by using the Geant4 (GEometry ANd Tracking 4)-DNA extension of the Geant4 toolkit. The results showed that, B-DNA has the lowest yield of simple strand breaks with 2.23 × 10{sup −10} Gy{sup −1} Da{sup −1} and 1.0 × 10{sup −11} Gy{sup −1} Da{sup −1} for the SSB and DSB damage yield, respectively. The A-DNA has the highest SSB yield with 3.59 × 10{sup −10} Gy{sup −1} Da{sup −1} and the Z-DNA has the highest DSB yields with 1.8 × 10{sup −11} Gy{sup −1} Da{sup −1}. It has been concluded that there is a direct correlation between the hit probability, mean specific imparted energy and SSB yield in each model of DNA. Moreover, there is a direct correlation between the DSB yield and both the mean lineal energy and topological characteristics of each model.

  20. Displacement correction factor versus effective point of measurement in depth dose curve measurements at 60Co gamma rays

    International Nuclear Information System (INIS)

    The discrepancies in data sets of values of the Displacement Factor pd recommended by different codes of practices for calibration purpose still demand further investigation to clarify this point. In this paper, we propose an experimental method to determine the displacement factor for cylindrical ionization chambers (thimble chambers) in photon beams. Measurements of pd for several depths were performed for 60Co gamma rays. From these results we calculated the shift of the effective point of measurement (z-zeff) for different depths. The results obtained in this work shown: (a) there is no significant change in pd from 2 cm to 17 cm of depth in water; (b) the value of pd for a ion-chamber Farmer type (inner radius r = 3.15 cm) is pd 0.988; (c) the shift of the effective point of measurement has a smooth variation with depth; (d) the value of (z-zeff) at the recommended calibration depth for 60Co beams (5 cm) is 0.6r (with r: inner radius of the chamber). The result (b) confirms the value of pd suggested by the SEFM and NACP protocols and differs with that of the AAPM. The value obtained for (z - zeff) (d) is very closed to that recommended by the IAEA TRS-277. Finally, the results (a) and (c) suggest that it should be preferable to use the displacement factor instead of effective point of measurement to perform measurements of depth dose curves, since the use of zeff should take into account its dependence on depth. (author). 7 refs, 4 figs

  1. Characteristic evaluation of papain irradiated with {sup 60}Co {gamma}-rays for the purpose of sterilization

    Energy Technology Data Exchange (ETDEWEB)

    Furuta, Masakazu; Ohashi, Isao; Oka, Masahito; Hayashi, Toshio [Osaka Prefectural Univ., Sakai (Japan). Research Inst. for Advanced Science and Technology

    1998-09-01

    To establish irradiation sterilization method for hybrid biomedical materials containing bioactive molecules together with artificial polymers, we employed dry powder and aqueous solution of papain as a model and examined radiation tolerance with {sup 60}Co {gamma}-rays. The dry powder and frozen aqueous solution showed significant resistance after 30-kGy irradiation, indicating that commercial irradiation sterilization method for disposable medical supplies was applicable. Unfrozen aqueous solutions (10mg/ml), in contrast, showed significant drop of enzymatic activity within the early period of irradiation (ca. 0.5kGy) but 40% of the activity was recovered at ca. 3-kGy before total inactivation at 15kGy. Taking various conditions including dose rate, concentration of enzyme, oxygen and nitrogen bubbling into irradiation inactivation experiments, we demonstrated that inactivation of papain could be controlled under anoxic condition, such as nitrogen bubbling, increasing sample volume at high dose rates and high concentration of enzyme where dissolved oxygen was consumed rapidly. It is suggested that radiation inactivation of papain in the aqueous solution was occurred through reversible oxidation of the sulfhydryl group at the active site by free radicals derived from radiolysis of water and dissolved oxygen. (author)

  2. Numerical simulation of 60Co-gamma irradiation effects on electrical characteristics of n-type FZ silicon X-ray detectors

    Science.gov (United States)

    Vigneshwara Raja, P.; Rao, C. V. S.; Narasimha Murty, N. V. L.

    2016-07-01

    This paper describes the gamma irradiation effects on the electrical characteristics of n-type float zone (FZ) silicon detectors by incorporating a 4-level 60Co-gamma radiation damage model in the commercial device simulator for plasma X-ray tomography diagnostics. In the simulations, a segmented n-type silicon detector (i.e. p+-n-n+ structure) is considered with varying substrate resistivity (ρ = 5.4, 2.5, and 0.3 kΩ cm). The simulation results have been validated with the reported experimental measurements carried out on similar device structures. The 60Co-gamma irradiation induced changes in the electrical characteristics of the detectors are analyzed up to the dose of 3500 Mrad. The possible gamma induced degradation in the X-ray response of the detectors is investigated from the changes in the effective doping concentration and the leakage current of the detectors. The survival of the gamma irradiated detectors is predicted from the simulation studies. The comparison between the 60Co-gamma and 14.1 MeV neutron irradiation effects (typical fusion environments) on silicon detectors is attempted.

  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 γ-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. (60)Co in cast steel matrix: A European interlaboratory comparison for the characterisation of new activity standards for calibration of gamma-ray spectrometers in metallurgy.

    Science.gov (United States)

    Tzika, Faidra; Burda, Oleksiy; Hult, Mikael; Arnold, Dirk; Marroyo, Belén Caro; Dryák, Pavel; Fazio, Aldo; Ferreux, Laurent; García-Toraño, Eduardo; Javornik, Andrej; Klemola, Seppo; Luca, Aurelian; Moser, Hannah; Nečemer, Marijan; Peyrés, Virginia; Reis, Mario; Silva, Lidia; Šolc, Jaroslav; Svec, Anton; Tyminski, Zbigniew; Vodenik, Branko; Wätjen, Uwe

    2016-08-01

    Two series of activity standards of (60)Co in cast steel matrix, developed for the calibration of gamma-ray spectrometry systems in the metallurgical sector, were characterised using a European interlaboratory comparison among twelve National Metrology Institutes and one international organisation. The first standard, consisting of 14 disc shaped samples, was cast from steel contaminated during production ("originally"), and the second, consisting of 15 similar discs, from artificially-contaminated ("spiked") steel. The reference activity concentrations of (60)Co in the cast steel standards were (1.077±0.019) Bqg(-1) on 1 January 2013 12h00 UT and (1.483±0.022) Bqg(-1) on 1 June 2013 12h00 UT, respectively.

  5. (60)Co in cast steel matrix: A European interlaboratory comparison for the characterisation of new activity standards for calibration of gamma-ray spectrometers in metallurgy.

    Science.gov (United States)

    Tzika, Faidra; Burda, Oleksiy; Hult, Mikael; Arnold, Dirk; Marroyo, Belén Caro; Dryák, Pavel; Fazio, Aldo; Ferreux, Laurent; García-Toraño, Eduardo; Javornik, Andrej; Klemola, Seppo; Luca, Aurelian; Moser, Hannah; Nečemer, Marijan; Peyrés, Virginia; Reis, Mario; Silva, Lidia; Šolc, Jaroslav; Svec, Anton; Tyminski, Zbigniew; Vodenik, Branko; Wätjen, Uwe

    2016-08-01

    Two series of activity standards of (60)Co in cast steel matrix, developed for the calibration of gamma-ray spectrometry systems in the metallurgical sector, were characterised using a European interlaboratory comparison among twelve National Metrology Institutes and one international organisation. The first standard, consisting of 14 disc shaped samples, was cast from steel contaminated during production ("originally"), and the second, consisting of 15 similar discs, from artificially-contaminated ("spiked") steel. The reference activity concentrations of (60)Co in the cast steel standards were (1.077±0.019) Bqg(-1) on 1 January 2013 12h00 UT and (1.483±0.022) Bqg(-1) on 1 June 2013 12h00 UT, respectively. PMID:27236833

  6. Effects of seed treatment with 60Co gamma rays and micronutrients on germination and growth of corn seedlings

    International Nuclear Information System (INIS)

    Gamma irradiation and soaking in solutions of some micronutrient elements, as presowing treatments of corn seeds, towards improving the germination of seeds, and increasing the growth of seedlings were investigated. The seeds were exposed to 12 irradiation doses of gamma rays ranging from 250-8000R. It was found that stimulatory effects on the germination percentage and capacity of seeds as well as the height and the dry weight of seedlings were exerted only by the low irradiation doses from 500-1000 R. Soaking cornseeds, before sowing, in any of the 4 concentrations ranging from 250-1000 ppm of molybdenum, manganese and zinc indicated that molybdenum treatment increased plant height the dry weight of seedlings; 500 ppm molybdenum gave the best effect. Irradiation of 500 ppm molybdenum soaked seeds with low doses of gamma rays stimulated the germination process and early growth of seedlings, with the 500 R dose being most effective. (author)

  7. Calculation of direct effects of 60Co gamma rays on the different DNA structural levels: A simulation study using the Geant4-DNA toolkit

    International Nuclear Information System (INIS)

    In this study, simple single strand breaks (SSB) and double strand breaks (DSB) due to direct effects of the secondary electron spectrum of 60Co gamma rays on different organizational levels of a volume model of the B-DNA conformation have been calculated using the Geant4-DNA toolkit. Result of this study for the direct DSB yield shows a good agreement with other theoretical and experimental results obtained by both photons and their secondary electrons; however, in the case of SSB a noticeable difference can be observed. Moreover, regarding the almost constant yields of the direct strand breaks in the different structural levels of the DNA, calculated in this work, and compared with some theoretical studies, it can be deduced that the direct strand breaks yields depend mainly on the primary double helix structure of the DNA and the higher-order structures cannot have a noticeable effect on the direct DNA damage inductions by 60Co gamma rays. In contrast, a direct dependency between the direct SSB and DSB yields and the volume of the DNA structure has been found. Also, a further study on the histone proteins showed that they can play an important role in the trapping of low energy electrons without any significant effect on the direct DNA strand breaks inductions, at least in the range of energies used in the current study

  8. Calculation of direct effects of {sup 60}Co gamma rays on the different DNA structural levels: A simulation study using the Geant4-DNA toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Tajik, Marjan; Rozatian, Amir S.H. [Department of Physics, University of Isfahan, Hezar Jarib Street, Isfahan 81746-73441 (Iran, Islamic Republic of); Semsarha, Farid, E-mail: Semsarha@ibb.ut.ac.ir [Institute of Biochemistry and Biophysics (IBB), University of Tehran, P.O. Box: 13145-1384, Tehran (Iran, Islamic Republic of)

    2015-03-01

    In this study, simple single strand breaks (SSB) and double strand breaks (DSB) due to direct effects of the secondary electron spectrum of {sup 60}Co gamma rays on different organizational levels of a volume model of the B-DNA conformation have been calculated using the Geant4-DNA toolkit. Result of this study for the direct DSB yield shows a good agreement with other theoretical and experimental results obtained by both photons and their secondary electrons; however, in the case of SSB a noticeable difference can be observed. Moreover, regarding the almost constant yields of the direct strand breaks in the different structural levels of the DNA, calculated in this work, and compared with some theoretical studies, it can be deduced that the direct strand breaks yields depend mainly on the primary double helix structure of the DNA and the higher-order structures cannot have a noticeable effect on the direct DNA damage inductions by {sup 60}Co gamma rays. In contrast, a direct dependency between the direct SSB and DSB yields and the volume of the DNA structure has been found. Also, a further study on the histone proteins showed that they can play an important role in the trapping of low energy electrons without any significant effect on the direct DNA strand breaks inductions, at least in the range of energies used in the current study.

  9. Selective expression of mutated p53 in human cells immortalized with either 4-nitroquinoline 1-oxide or 60Co gamma rays

    International Nuclear Information System (INIS)

    Many studies on in vitro transformation of human cells indicate that the cells must be immortalized before they can be neoplastically transformed, indicating that immortalization is a critical step in multistep neoplastic transformation of human cells. We immortalized three human cell lines by repeated treatment with either 60Co gamma rays or a chemical carcinogen, 4-nitroquinoline 1-oxide, and found that all three immortalized cell lines have mutations in the tumor suppressor gene, p53. Direct sequencing of the reverse-transcribed mRNA and immunoprecipitation of p53 protein revealed that mutant p53 is selectively expressed in all the immortalized cell lines, whereas the genomic fragments of the immortalized cells contain wild-type and mutated p53 alleles. Although the mutated p53 is selectively expressed in the immortalized cells, expression of the wild-type p53 was induced by treatment of the cells with a hypomethylating reagent, 5-azacytidine, indicating that the wild-type p53 allele might be inactivated by hypermethylation of DNA. Actually, the entire genomic locus including the promoter region of p53 is hypermethylated in all the immortalized cell lines. Expression and phosphorylation of Rb was normal in these three cell lines. Thus, inactivation of both wild type p53 alleles and selective expression of mutated p53 seem to be key factors in the immortalization of human fibroblasts. (author)

  10. Action of Bothrops moojeni venom and its L-amino acid oxidase fraction, treated with 60Co gamma rays, in Leishmania spp

    International Nuclear Information System (INIS)

    Bothrops moojeni venom showed an anti leishmania activity in vitro, as determined by a cell viability assay using the reduction of MTT. After venom purification, by chromatography techniques, the fractions with anti leishmania and L-amino acid oxidase activities, eluted in the same positions. The molecular weight of the enzyme was estimated to be 140 kDa by molecular exclusion chromatography, and 69 kDa, by SDS-PAGE, migrating as a single band, with an isoelectric point of 4.8 as determined by isoelectric focusing. The purified LAO from B. moojeni venom, 135-fold more active than crude venom, showed homo dimeric constitution, and was active against Leishmania spp from the New World, with an effective concentration against L(L). amazonensis of 1.80 μg/ml (EC50), L.(V.) panamensis (0.78 |μg/ml) and L.(L.) chagasi (0.63 (μg/ml). Ultrastructural studies of promastigotes affected by LAO demonstrated cell death, with edema in several organelles such as mitochondria and nuclear membrane, before cell disruption and necrosis. The action of LAO was demonstrated to be hydrogen peroxide-dependent. Studies with LLCMK-2 cells, treated with LAO, showed a toxic effect, with an EC50 of 11|μg/ml. Irradiation of LAO with 60Co gamma rays, did not affect its whole oxidative activity, neither detoxified the enzyme. Amastigotes treated with LAO were not affected by its hydrogen peroxide, otherwise, the exogenous product, killed amastigotes with an EC50 of 0.67mM. These data could be of help in the development of alternative therapeutic approaches to the treatment of leishmaniasis. (author)

  11. Experimental calibration and determination of the relative response for Lif: Mg, Ti(TLD-100) dosemeters at 60Co gamma and 60 kVp X-ray energies

    International Nuclear Information System (INIS)

    The thermoluminescence efficiency of LiF: Mg, Ti (TLD-100) dosemeters has been determined for photon beams from 60Co gamma rays and 60 kVp X-rays. It has been proven that light yield varies as a function of the photon energy. An experiment was performed using an X-ray beam whose spectrum has been determined by an X-ray fluorescence method. This enabled a direct calculation of the absorbed doses in the T1 material for the different operation conditions. These values and the experimental ones from measuring T1 intensities have been used to obtain the efficiency for energy X-ray spectrum. From the above values, the dosemeter T1 response, relative to 60Co, has been evaluated. (author)

  12. Study of {sup 60}Co as gamma source in backscatter gamma densitometers

    Energy Technology Data Exchange (ETDEWEB)

    Gholipour Peyvandi, R.; Taheri, A.; Rahmanzadeh Tootkaleh, S.; Askari Lehdarboni, M. [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Islami Rad, S.Z. [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Univ. of Qom (Iran, Islamic Republic of). Dept. of Physic

    2015-07-15

    In this work the performance of backscatter gamma densitometer is studied using {sup 60}Co as gamma source. The ability of the densitometer to determine the liquid's interfaces in multi-phase flows was assessed. The aim mainly was to investigate the possibility of using {sup 60}Co in this system. Furthermore, a comparison between {sup 60}Co and was done. The obtained results indicate that {sup 60}Co can be advantageous in this regard.

  13. Gamma 60Co DL50/30 of Biomphalaria glabrata (Say, 1818) DL50/30 raios gama de 60Co em Biomphalaria glabrata (Say, 1818)

    OpenAIRE

    Elaine Barros da Costa CARVALHO; Melo, Ana Maria Mendonça de Albuquerque; Mauricy Alves da MOTTA

    1999-01-01

    The variation of resistance to 60Co gamma-rays of Biomphalaria glabrata was studied. A population of 480 mollusks was observed during 30 days - distributed in 8 groups of snails isolated and 8 groups of snails in colonies - after exposure (30 snails per group per dose) to increasing doses of gamma radiation. Doses of 10, 20, 40, 60, 80, 160, 320 and 640 Gy from a Gamma-cell 60Co irradiator, were applied to the test groups and two groups control (non-irradiated) of snails - isolated and colony...

  14. 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)

  15. Investigation of the /sup 59/Co(n,. gamma. )/sup 60/Co reaction with unpolarized and polarized neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Kopecky, J. (Stichting Energieonderzoek Centrum Nederland, Petten. Nuclear Structure Group); Delfini, M.G. (Stichting Energieonderzoek Centrum Nederland, Petten. Nuclear Structure Group; Rijksuniversiteit Utrecht (Netherlands). Fysisch Lab.); Chrien, R.E. (Brookhaven National Lab., Upton, NY (USA))

    1984-10-15

    Capture of 24 keV neutrons and polarized as well as unpolarized thermal neutrons in /sup 59/Co has been investigated. Of the 350 ..gamma..-rays observed 335 could be placed in a /sup 60/Co level scheme containing 144 levels. The reaction Q-value amounts to 7491.92(8) keV. The chi/sup 2/ analysis of the circularly polarized ..gamma..-rays results in 31 unambiguous spin assignments for /sup 60/Co levels. The fraction of the J=4/sup -/ channel in the thermal capture was determined to be (80 +- 1)%. An average ..gamma..-ray multiplicity of 2.3 gammas per neutron capture was observed. The resulting level scheme is compared to shell-model predictions. Possible reaction mechanisms are discussed.

  16. Performance of a Roos ionization chamber in gamma radiation beams ({sup 60}Co)

    Energy Technology Data Exchange (ETDEWEB)

    Perini, Ana P.; Neves, Lucio P.; Caldas, Linda V.E., E-mail: lcaldas@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Among the different types of dosimetry instruments, the ionization chambers are the most practical and and important radiation measurement devices due to their high sensitivity and relatively constant response within a wide range of energies. A commercial PTW ionization chamber (Roos electron chamber) usually utilized in X-ray beams, was tested to verify the possibility of its dosimetric application in {sup 60}Co beams. The main tests in this work were: short- and long-term stability, saturation, ion collection efficiency, polarity effect, leakage current and angular dependence. The characterization tests were performed using a Gammatron {sup 60}Co irradiator and a special goniometer made of PMMA. All results were within international recommendations. The reproducibility test presented results within the recommended limit of {+-}1%, and all coefficients of variation observed in the repeatability test were lower than {+-}0.07%. The ion collection efficiency was better than 99.9% for both polarities. For all pairs of polarity evaluated during the saturation test, the polarity effect was lower than the recommended limit. The maximum variation obtained for angular dependence test was only 0.5%. The chamber tested in this work achieved the expected results in the case of all pre-operational tests realized: stability, leakage current, angular dependence, saturation, ion collection and polarity effect. Evaluating the satisfactory results obtained, it is possible to indicate the usefulness of this ionization chamber for dosimetry in {sup 60}Co gamma radiation beams. (author)

  17. The Design of 60Co Container for Gamma Ray Radiography System%用于γ辐射成像系统的60Co源容器的设计

    Institute of Scientific and Technical Information of China (English)

    刘锡明; 吴志芳; 谈春明; 张颜民

    2012-01-01

    放射性同位素是辐射成像中常用的射线源,具有输出射线强度稳定、空间分布均匀恒定、操作维护简便、射线能量较单一、节能等优点,但是也存在防护和安全方面的问题,因此设计和开发功能完善、防护适当、安全可靠的放射源工作及储存容器十分重要.在60Co高精度工业CT系统中,依据相关国家标准,采用特殊的结构、屏蔽及安全设计,制作了60Co射线源的工作及储存容器.经实际测量,距容器表面5 cm和1m处空气吸收剂量率分别为170 μGy/h和5μGy/h.该容器功能完善、操作便利、结构坚固,具有多重安全设计,很好地满足了系统的检测要求,保障了人员的辐照安全.%Radioactive isotopes are frequently used in radiography systems as they have many advantages for imaging. For example, the intensity and spatial distnbuiion ol the gamma ray emitted are stable. The energy of gamma photons is fairly identical for most frequently used isotopes. The operation and maintenance are easy and require less energy. However, they are difficulties in their application in therms of radiation protection and safety. To solve this problem, it's very important to develop a fully functional, properly radiation protected, safe and reliable working and storage container for the radioactive source. In the 60Co high-precision industrial CT system, based on the corresponding national standards, the 60Co working and storage container was successfully developed by specific design of structure, shielding and security. The air absorbed dose rate was 170 μGy/h at 5 cm distance from the container surface and 5 μGy/h at 1 m distance according to actual measurements. The container has fall function- easy operation, robust construction and multiple safety measures. It meets requirements of the system and ensures operator's safety very well.

  18. Gamma {sup 60} Co D L {sub 50/30} of Biomphalaria glabrata (Say, 1818)

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Elaine Barros da Costa; Melo, Ana Maria Mendonca de Albuquerque; Motta, Mauricy Alves da [Pernambuco Univ., Recife, PE (Brazil). Dept. de Biofisica e Radiobiologia

    1999-12-01

    The variation of resistance to {sup 60} Co gamma-rays of Biomphalaria glabrata was studied. A population of 480 mollusks was observed during 30 days - distributed in 8 groups of snails isolated and 8 groups of snails in colonies - after exposure (30 snails per group per dose) to increasing doses of gamma radiation. Doses of 10, 20 40, 60, 80, 160, 320 and 640 Gy from a Gamma-cell {sup 60} Co irradiator, were applied to the test groups and two groups control (non-irradiated) of snails - isolated and colony - were kept apart. After have been exposed, the snails were drew back to the aquaria where they were maintained before. The survival was estimated on a daily score of the alive animals in each group-dose, starting after the irradiation exposure day. As a result, the survival self-fertilization forms (DL{sub 50/30}=218.2 Gy) was found greater than in cross-fecundation forms. These data point to allow radio-resistance on the cross-fertilization forms - the sexual reproductive form - which is most found in nature. The lower radio-resistance of the cross-fertilization forms suggests the presence of some sex-linked hormonal factor related to this phenomenon. (author)

  19. Gamma 60 Co D L 50/30 of Biomphalaria glabrata (Say, 1818)

    International Nuclear Information System (INIS)

    The variation of resistance to 60 Co gamma-rays of Biomphalaria glabrata was studied. A population of 480 mollusks was observed during 30 days - distributed in 8 groups of snails isolated and 8 groups of snails in colonies - after exposure (30 snails per group per dose) to increasing doses of gamma radiation. Doses of 10, 20 40, 60, 80, 160, 320 and 640 Gy from a Gamma-cell 60 Co irradiator, were applied to the test groups and two groups control (non-irradiated) of snails - isolated and colony - were kept apart. After have been exposed, the snails were drew back to the aquaria where they were maintained before. The survival was estimated on a daily score of the alive animals in each group-dose, starting after the irradiation exposure day. As a result, the survival self-fertilization forms (DL50/30=218.2 Gy) was found greater than in cross-fecundation forms. These data point to allow radio-resistance on the cross-fertilization forms - the sexual reproductive form - which is most found in nature. The lower radio-resistance of the cross-fertilization forms suggests the presence of some sex-linked hormonal factor related to this phenomenon. (author)

  20. Human fibroblasts (KMST-6/RAS line) transformed with 60Co gamma-rays and c-Ha-ras oncogene constitutively produce a large amount of human granulocyte-colony stimulating factor (G-CSF)

    International Nuclear Information System (INIS)

    Human fibroblasts (KMST-6/RAS) transformed with 60Co gamma-rays and the Ha-ras oncogene formed tumors in nude mice. These mice showed splenomegaly and an increase in granulocytes in the peripheral blood. There was a direct correlation between tumor size and spleen size. Histologically, prominent proliferation of granulocytes was observed in the enlarged spleen. These findings indicated that KMST-6/RAS cells might have been producing granulocyte colony-stimulating factor (G-CSF) in the nude mice. In fact, in vitro studies demonstrated that the cells produced G-CSF in the culture medium and that production of G-CSF was greater during the logarithmic growth than during the stationary phase. Nearly equal amounts of G-CSF were produced by cells grown in serum-free or 10% serum-supplemented medium. Neither expression of the ras oncogene nor the tumorigenicity of cells correlated with the production of G-CSF. G-CSF production in KMST-6/RAS cells was significantly stimulated by butyrate, but not by dexamethasone or 5-azacytidine. (author)

  1. Effect of 60Co-gamma whole-body irradiation on serum amylase level

    International Nuclear Information System (INIS)

    Changes of serum amylase activity in rats, after several doses of acut 60Co-gamma irradiation as a function of time were investigated. These changes proved to be of no diagnostic value in early radiation damage. (author)

  2. Resveratrol Effects on Life Span and Fertility of Caenorhabditis Elegans Subject to 60Co Gamma Ray Irradiation%白藜芦醇对60Coγ射线照射线虫寿命和生殖的影响

    Institute of Scientific and Technical Information of China (English)

    叶侃; 季晨博; 郭锡熔; 古桂雄

    2011-01-01

    Caenorhabditis elegans was used as experimental model to investigate radiation effect of resveratol on caenorhabdities elegans irradiated by 60Co γray. Treatment with resveratrol can increase average life span and spawning rate, improve the surrival rate of eggs, and protect their mitochondrion function of cacnorhabdities elegans exposure to 60Co rr ray. The results indicate that resveratrol has radiation protection effects, which might be related to its action on ROS decrease and mitochondrial defend.%以线虫作为实验模型,观察白藜芦醇(RES)对受60Coγ射线照射线虫的保护作用.结果表明,白藜芦醇能提高受照射线虫的寿命,增加产卵率,提高卵的存活率,保护其线粒体功能.其作用机制可能与白藜芦醇减轻氧自由基所致的线虫线粒体损伤有关.

  3. Decoloration Kinetics of Waste Cooking Oil by 60Co γ-ray/H2O2

    Science.gov (United States)

    Xiang, Yulin; Xiang, Yuxiu; Wang, Lipeng

    2016-03-01

    In order to decolorize, waste cooking oil, a dark red close to black solution from homes and restaurants, was subjected to 60Co γ-ray/H2O2 treatment. By virtue of UV/Vis spectrophotometric method, the influence of Gamma irradiation to decoloration kinetics and rate constants of the waste cooking oil in the presence of H2O2 was researched. In addition, the influence of different factors such as H2O2 concentration and irradiation dose on the decoloration rate of waste cooking oil was investigated. Results indicated that the decoloration kinetics of waste cooking oil conformed to the first-order reaction. The decoloration rate increased with the increase of irradiation dose and H2O2 concentration. Saponification analysis and sensory evaluation showed that the sample by 60Co γ-ray/H2O2 treatment presented better saponification performance and sensory score. Furthermore, according to cost estimate, the cost of the 60Co γ-ray/H2O2 was lower and more feasible than the H2O2 alone for decoloration of waste cooking oil.

  4. Dose-dependent and gender-related radiation-induced transcription alterations of Gadd45a and Ier5 in human lymphocytes exposed to gamma ray emitted by 60Co

    International Nuclear Information System (INIS)

    Growth arrest DNA damage-inducible 45a gene (Gadd45a) and immediate early response gene 5 (Ier5) have been emphasised as ideal radiation bio-markers in several reports. However, some aspects of radiation-induced transcriptional alterations of these genes are unknown. In this study, gender-dependency and dose-dependency as two factors that may affect radiation induced transcription of Gadd45a and Ier5 genes were investigated. Human lymphocyte cells from six healthy voluntary blood donors (three women and three men) were irradiated in vitro with doses of 0.5-4.0 Gy from a 60Co source and RNA isolated 4 h later using the High Pure RNA Isolation Kit. Dose and gender dependency of radiation-induced transcriptional alterations of Gadd45a and Ier5 genes were studied by quantitative real-time polymerase chain reaction. The results showed that as a whole, Gadd45a and Ier5 gave responses to gamma rays, while the responses were independent of radiation doses. Therefore, regardless of radiation dose, Gadd45a and Ier5 can be considered potential radiation bio-markers. Besides, although radiation-induced transcriptional alterations of Gadd45a in female and male lymphocyte samples were insignificant at 0.5 Gy, at other doses, their quantities in female samples were at a significantly higher level than in male samples. Radiation induced transcription of Ier5 of females samples had a reduction in comparison with male samples at 1 and 2 Gy, but at doses of 0.5 and 4 Gy, females were significantly more susceptible to radiation-induced transcriptional alteration of Ier5. (authors)

  5. DNA double-strand break and apoptosis induction in human lymphocytes in different cycle cell phases by 60Co gamma rays and Bragg peak protons of a medical beam

    International Nuclear Information System (INIS)

    A comparative analysis is made of the regularities in the formation of DNA double-strand break and apoptosis induction in peripheral human blood lymphocytes in different cell cycle phases after 60Co gamma and extended Bragg peak proton irradiation. It is shown that the formation of apoptotic cells in a lymphocyte population increases linearly in all the cell cycle stages after proton irradiation. The maximal DNA double-strand break and apoptosis yield in lymphocytes is observed in the S phase of the cell cycle

  6. Evaluation of fruit productivity and quality in Hass avocado submitted to 60Co gamma radiation

    International Nuclear Information System (INIS)

    Evaluation of productivity, postharvest behavior and fruit quality was performed on four years Hass avocado trees irradiated with 60 Co gamma rays in doses of 5, 10, 15, 20 and 25 Gy, established in the ''La Labor'' Experimental Center of the Centro de Investigaciones Cientificas y Tecnologias del Aguacate en el Estado de Mexico (CICTAMEX) at Temascaltepec Mexico. Productivity had a significant increase in the dose of 15 Gy being the average number of fruits nearly 400 % more than the control at fruit setting, being such difference reduced at fruit harvesting to 300 %. In regard to postharvest performance, the respiration index (mg CO2/kg/hr) did not show significant differences among treatments. Also others variables such as physiological weight losses, texture, maturity pattern, and sensorial tests (color, flavor, aroma, texture) were not different in regard to the control. This mean that radiation has altered productivity but not the quality and postharvest behavior of fruits. (Author)

  7. Immunohistochemical study on effects of [sup 60]Co [gamma] irradiation on salivary gland ducts of rat

    Energy Technology Data Exchange (ETDEWEB)

    Saitoh, Kazuhiko (Meikai Univ., Sakato, Saitama (Japan). School of Dentistry)

    1992-09-01

    Cytokeratin distribution in salivary glands was detected by use of polyclonal antikeratin antiserum (TK) and monoclonal antibodies (KL 1, RGE 53, and RPN 1164). The salivary glands of male rats received either 17.82 Gy or 27.97 Gy [sup 60]Co [gamma] irradiation in a single exposure and were then compared immunohistochemically with those of normal rats. Polyclonal anti-keratin antiserum (TK), which reacts with 41-65 KD keratins, stained almost all ducts in normal glands. RPN 1164 (no. 8 keratin) staining was negative in intercalated ducts of normal parotid and submandibular glands, but strongly positive in both striated and excretory ducts of these glands. Monoclonal antibody KL 1 (55-57 KD keratins) and RGE 53 (no. 18 keratin) did not bind to any ductal or acinar epithelia. Only in the sublingual gland were acini positive for TK staining, possibly indicating myoepithelial cells. No effects of [sup 60]Co [gamma] irradiation were apparent regarding keratin distribution in the intercalated in apical cytoplasm by [sup 60]Co [gamma] irradiation. Also, in the excretory duct, the basal side of the cells exhibited weakened staining following [sup 60]Co [gamma] irradiation were the most significant in the parotid and the least in the sublingual gland. Also this reaction depended upon the doses of [sup 60]Co used. The present findings suggested that negative or weakened staining at the basal and perinuclear portions of striated duct cells specifically reflects the primary or secondary cell damage produced by [sup 60]Co [gamma] irradiation. Since the distribution of cytoskeletal proteins in the cytoplasm reflects certain pathological conditions, immunohistochemical detection of these proteins seem to have a diagnostic value with respect to cellular injury. (J.P.N.) 77 refs.

  8. Activity evaluation from different native or irradiated with {sup 60} Co gamma rays snake venoms and their inhibitory effect on Leishmania (Leishmania) amazonensis; Avaliacao da atividade de diferentes venenos de serpentes, nativos ou irradiados, com radiacao gama de {sup 60} Co, quanto ao poder inibitorio do crescimento de Leishmania (Leishmania) amazonensis

    Energy Technology Data Exchange (ETDEWEB)

    Lourenco, Cecilia de Oliveira

    2000-07-01

    Cutaneous leishmaniasis is a disease, caused by Leishmania parasites, that occurs frequently in tropical and sub-tropical regions of the world. Skin lesions that could results in disfiguring aspect characterize it. The treatment is based on few drugs as antimony salts or pentamidine that are toxic with increasing resistance by the parasite. Alternative forms of disease treatment are in constant search, including natural components as snake venoms. Previous studies demonstrate that some components of snake venoms have an inhibitory effect against those parasites, including Leishmania species. Although snake venoms presented high toxicity, several methods have been described to detoxify most or some of their toxic components, with favorable results by the use of gamma irradiation. In this report we tested several native and irradiated snake venoms for inhibitory effect against Leishmania (Leishmania) amazonensis parasite and LLCMK{sub 2} mammalian cells, with enzymatic tests and electrophoresis. There are significant activity in Acanthophis antarcticus, Agkistrodon bilineatus, Bothrops moojeni, Bothrops jararaca, Hoplocephalus stephensi, Naja melanoleuca, Naja mossambica, Pseudechis australis, Pseudechis colletti, Pseudechis guttatus and Pseudechis porphyriacus, venom being inactive Pseudonaja textilis, Notechis ater niger, Notechis scutatus. Oxyuranus microlepidotus and Oxyuranus scutellatus venoms. After 2 KGy of {sup 60}Co irradiation most venom loses significantly their activity. Venoms with antileishmanial activity presented L-amino acid oxidase (L-AO) activity and showed common protein with a molecular weight about 60kDa in SDS-PAGE. These results indicate that L-AO activity in those venoms are probably related with antileishmanial effect. (author)

  9. Monte Carlo calculation of 60Co γ-ray's albedo-dose rate from the air

    International Nuclear Information System (INIS)

    The Monte Carlo calculation of 60Co γ-ray's albedo-dose rate from the air is reported. A formula is presented with which the relations of the albedo-doserate with some parameters are simulated and fitted

  10. Gamma 60Co DL50/30 of Biomphalaria glabrata (Say, 1818 DL50/30 raios gama de 60Co em Biomphalaria glabrata (Say, 1818

    Directory of Open Access Journals (Sweden)

    Elaine Barros da Costa CARVALHO

    1999-11-01

    Full Text Available The variation of resistance to 60Co gamma-rays of Biomphalaria glabrata was studied. A population of 480 mollusks was observed during 30 days - distributed in 8 groups of snails isolated and 8 groups of snails in colonies - after exposure (30 snails per group per dose to increasing doses of gamma radiation. Doses of 10, 20, 40, 60, 80, 160, 320 and 640 Gy from a Gamma-cell 60Co irradiator, were applied to the test groups and two groups control (non-irradiated of snails - isolated and colony - were kept apart. After have been exposed, the snails were drew back to the aquaria where they were maintained before. The survival was estimated on a daily score of the alive animals in each group-dose, starting after the irradiation exposure day. As a result, the survival self-fertilization forms (DL50/30 = 218.2 Gy was found greater than in cross-fecundation forms. These data point to a low radio-resistance on the cross-fertilization forms - the sexual reproductive form - which is most found in nature. The lower radio-resistance of the cross-fertilization forms suggests the presence of some sex-linked hormonal factor related to this phenomenon.A variação da resistência entre indivíduos em autofecundação e fecundação cruzada de Biomphalaria glabrata foram estudadas. Uma população de 480 moluscos foi observada durante 29 dias, distribuída em 8 grupos de caramujos isolados e 8 grupos em colônias após a exposição (30 caramujos por grupo-dose a doses crescentes de radiação gama. Foram usadas doses de 10, 20, 40, 60, 80, 160, 320 e 640 Gy de um irradiador Gamma-Cell 60Co. Dois grupos não irradiados - isolado e colônia - foram separados como controle e após a irradiação todos os caramujos voltaram para aquários onde viviam antes. A sobrevida foi estimada pela contagem diária dos animais vivos em cada grupo-dose, a partir do dia da irradiação. O resultado mostrou maior sobrevivência nos grupos isolados (DL50/30 = 218.2 Gy que nos grupos

  11. 60Co gamma radiation effect on AlGaN/AlN/GaN HEMT devices

    Institute of Scientific and Technical Information of China (English)

    WANG Yan-Ping; LUO Yin-Hong; WANG Wei; ZHANG Ke-Ying; GUO Hong-Xia; GUO Xiao-Qiang; WANG Yuan-Ming

    2013-01-01

    The testing techniques and experimental methods of the 60Co gamma irradiation effect on AlGaN/AlN/GaN high electron mobility transistors (HEMTs) are established.The degradation of the electrical properties of the device under the actual radiation environment are analyzed theoretically,and studies of the total dose effects of gamma radiation on AlGaN/AlN/GaN HEMTs at three different radiation bias conditions are carried out.The degradation patterns of the main parameters of the AlGaN/AlN/GaN HEMTs at different doses are then investigated,and the device parameters that were sensitive to the gamma radiation induced damage and the total dose level induced device damage are obtained.

  12. 60Co gamma radiation effect on AlGaN//AlN/GaN HEMT devices

    International Nuclear Information System (INIS)

    The testing techniques and experimental methods of the 60Co gamma irradiation effect on AlGaN/AlN/GaN high electron mobility transistors (HEMTs) are established. The degradation of the electrical properties of the device under the actual radiation environment are analyzed theoretically, and studies of the total dose effects of gamma radiation on AlGaN/AlN/GaN HEMTs at three different radiation bias conditions are carried out. The degradation patterns of the main parameters of the AlGaN/AlN/GaN HEMTs at different doses are then investigated, and the device parameters that were sensitive to the gamma radiation induced damage and the total dose level induced device damage are obtained. (authors)

  13. The influence of 60Co gamma irradiation for downy mildew infection on corn

    International Nuclear Information System (INIS)

    Corn seeds of Genjah kertas variety were irradiated with 60Co gamma in the range of 0 rad - 40.000 rads, at interval of 2000 rads, as preliminary investigation to obtain possibilities of corn mutation. Several agronomical effects of radiation on the seedling-plant such as seed germination, height of the seedling, ages of flowering, ages of harvesting, length and circle of the cob, 100U dry seeds weight, number and diameter of stomata, and percentage of downy mildew infection have been observed. The exact conclusion can be obtained only after testing the results of M2 and M3. (author)

  14. Action of Bothrops moojeni venom and its L-amino acid oxidase fraction, treated with {sup 60}Co gamma rays, in Leishmania spp; Acao do veneno de Bothrops moojeni e sua fracao L-aminoacido oxidase, submetida ao tratamento com raios gama de {sup 60}Co, em Leishmania spp

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Andre Gustavo Tempone

    1999-07-01

    Bothrops moojeni venom showed an anti leishmania activity in vitro, as determined by a cell viability assay using the reduction of MTT. After venom purification, by chromatography techniques, the fractions with anti leishmania and L-amino acid oxidase activities, eluted in the same positions. The molecular weight of the enzyme was estimated to be 140 kDa by molecular exclusion chromatography, and 69 kDa, by SDS-PAGE, migrating as a single band, with an isoelectric point of 4.8 as determined by isoelectric focusing. The purified LAO from B. moojeni venom, 135-fold more active than crude venom, showed homo dimeric constitution, and was active against Leishmania spp from the New World, with an effective concentration against L(L). amazonensis of 1.80 {mu}g/ml (EC{sub 50}), L.(V.) panamensis (0.78 |{mu}g/ml) and L.(L.) chagasi (0.63 ({mu}g/ml). Ultrastructural studies of promastigotes affected by LAO demonstrated cell death, with edema in several organelles such as mitochondria and nuclear membrane, before cell disruption and necrosis. The action of LAO was demonstrated to be hydrogen peroxide-dependent. Studies with LLCMK-2 cells, treated with LAO, showed a toxic effect, with an EC{sub 50} of 11|{mu}g/ml. Irradiation of LAO with 6{sup 0C}o gamma rays, did not affect its whole oxidative activity, neither detoxified the enzyme. Amastigotes treated with LAO were not affected by its hydrogen peroxide, otherwise, the exogenous product, killed amastigotes with an EC{sub 50} of 0.67mM. These data could be of help in the development of alternative therapeutic approaches to the treatment of leishmaniasis. (author)

  15. Microstructural study of Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-x}/Ag samples irradiated with {sup 60}Co {gamma} rays at high doses

    Energy Technology Data Exchange (ETDEWEB)

    Rangel, R. [Programa de Postgrado en Fisica de Materiales, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Apartado Postal 2681, CP 22800, Ensenada, BC (Mexico); Galvan, D.H. [CECIMAC-UNAM, Apartado Postal 2681, CP 22800, Ensenada, BC (Mexico); Adem, E. [Instituto de Fisica-UNAM, Apartado Postal 20-364, CP 01000, Mexico DF (Mexico); Bartolo-Perez, P. [CINVESTAV-IPN Unidad Merida, Departamento de Fisica Aplicada, Merida, Yucatan (Mexico); Maple, M.B. [Physics Department and Institute for Pure and Applied Physical Sciences, La Jolla, CA (United States)

    1998-06-01

    We have investigated the damage induced by irradiation in Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-x} silver added samples. The samples were prepared with 0 and 6.5 wt% of silver and irradiated by high-energy {gamma} irradiation (50-150 Mrad). The roles of silver and dosage irradiation are discussed in terms of their effects on microstructure, crystallinity, critical temperature (T{sub c}) and zero-resistance temperature (T{sub 0}). After irradiation, T{sub c} decreased while the room-temperature electrical resistance increased by a factor of 8 for some of the samples. The difference in T{sub 0} between irradiated and non-irradiated YBCO samples was of the order of 10 K. We have found that the difference is bigger for silver-added samples. We have also observed several changes in diffraction patterns of YBCO and YBCO-silver samples. SEM images, EDS and XPS analysis showed that silver resided inside the grains as single atoms and as metallic clusters. The relative concentrations of the elements in samples were quantified by Auger electron spectroscopy. The values showed a gradual increase for radiation doses ranging between 0 and 100 Mrad. For doses up to 100 Mrad, J{sub c} decreased because of the weak-link breakage induced by high doses of {gamma} rays. (author)

  16. Some gamma radiation (60Co) effects on Chrysomya megacephala (Fabricius, 1794) (Diptira-Calliphoridae)

    International Nuclear Information System (INIS)

    The effect of different gama radiation (60Co) doses on Chrysomya megcephala (Fabricius) have been studied under laboratory conditions, in the Entomology Section of Centro de Energia Nuclear na Agricultura (CENA-USP), Piracicaba, SP, Brasil. The insects were collected close to sucking animals brooding areas, identified and reared on artificial diet, being kept in a temperature (26 +- 20C) and humidity (66 +- 9%) controlled room, with 12L:12D photopheriod. A Gammabeam type 650 Cobalt-60 gamma irradiation source was used, with 28, 196x1010 Bq activity at the beginning of the experiment. The pupae were submitted to increasing gamma radiation doses. To determine lethal doses, treatments were carried out at four different ages and to determine the sterilizing doses two-three day pupae were used. It was noted pupae radiosensitivity decreased with age, LD50 varying from 14 - 513 Gy. The sterilizing dose for males was 40 Gy and for females 30 Gy. During the individuals life cycle, it was noted that there was a decrease in life expectancy (exo) of adults when the gamma radiation dose was increased. Treated males were more sensitive than females (Crossed with ''normals''), there occurring a marked reduction in the number of eggs and their viability when the used gamma radiation dose was increased. (author)

  17. Cell survival of human tumor cells compared with normal fibroblasts following 60Co gamma irradiation

    International Nuclear Information System (INIS)

    Three tumor cell lines, two of which were shown to be HeLa cells, were irradiated with 60Co gamma irradiation, together with two cell cultures of normal human diploid fibroblasts. Cell survival was studied in three different experiments over a dose range of 2 to 14 gray. All the tumor cell lines showed a very wide shoulder in the dose response curves in contrast to the extremely narrow shoulder of the normal fibroblasts. In addition, the D/sub o/ values for the tumor cell lines were somewhat greater. These two characteristics of the dose response curves resulted in up to 2 orders of magnitude less sensitivity for cell inactivation of HeLa cells when compared with normal cells at high doses (10 gray). Because of these large differences, the extrapolation of results from the irradiation of HeLa cells concerning the mechanisms of normal cell killing should be interpreted with great caution

  18. Expression of FHIT in AHH-1 cells irradiated by 60Co γ-ray and bystander effect cells

    International Nuclear Information System (INIS)

    Objective: To investigate the expression of FHIT gene in the 60Co gamma-ray irradiated human lymphocytoblast (AHH-1) cell and the bystander effect cell, and to explore the function of FHIT gene in the bystander effect of ionizing radiation. Method: Preparation of bystander effect cell model: after inadiated with different dose of 60Co gamma-ray (0, 2, 5 Gy), the directly irradiated AHH-1 cells were collected immediately by centrifugation and co-cultivated with non-irradiated cells in Transwell, forming the bystander effect group P1. In addition, some culture media supematant of directly irradiated cells were transferred to the non- irradiated cells culture medium, forming the group P2. Then cells were collected at 0, 6, 12, and 24 h after irradiation and the total RNA and protein were extracted. RT-PCR and Western blot were performed to determine the FHIT mRNA and protein level, respectively. Flow cytometry assay and cell counting were conducted to detect the alteration of cell cycle and cell proliferation, respectively at 0, 24 h after irradiation. Results: The mRNA level of FHIT gene among control cells, directly irradiated cells and bystander cells showed no obvious difference, while the FHIT protein level of the directly irradiated cells and bystander cells was significantly down-regulated compared with the control cells (F=102.45, P2 phase arrest and obviously inhibited the proliferation ability. Conclusions: 2 and 5 Gy of 60Co γ-ray irradiated AHH-1 cells can result in down regulation of the FHIT protein expression, which suggests that FHIT gene is involved in the process of bystander effect induced by irradiation. (authors)

  19. Effect of 60Coray irradiation on green coffee beans, 1

    International Nuclear Information System (INIS)

    Green coffee beans were irradiated with 60Corays at doses of 0, 0.05, 0.5, 5.0 and 10.0 Mrad and the changes of general components in green and roast coffee beans were investigated together with those of the organoleptic properties of roast beans during storage according to the cup testing. In case of Brazil santos beans, irradiation of some 0.05 Mrad 60Coray gave rather favourable mild flavour and no harmful influence on the quality of coffee, and moreover, would tend to extend the shelf life of roast beans. But influence of irradiation on the quality of coffee differed somewhat between two cultivars, Brazil santos and Colombia. (auth.)

  20. The effect of 60Co γ-rays on Con A and LPS induced lymphocytes

    International Nuclear Information System (INIS)

    The effect to 60Co γ-rays on lymphocytes induced by Con A and LPS and the relationship between these two groups of cells were investigated by means of 3H-TdR incorporation. The study showed that in vitro, Con A cells were able to promote the inducing effect of LPS to B cells. When Con A cells were irradiated by 10 Gy γ-rays, the 3H-TdR incroporation value reduced significanly and the stimulating effect of Con A cells on LPS cells disappeared. Having been irradiated by γ-rays, LPS cells were not able to be stimulated by normal Con A cells. When the groups of cells were incubated together after irradiation, the synergistic function disappeared, furthermore the suppressive effect of Con A cells on LPS cells emerged. When these two groups of cells were investigated by means of agar culture, the suppressive effect of 10 Gy-γ-rays on lymphocytes colony formation was more obvious. Tests on 8 patients who were suffering from carcinoma of nasopharynx showed that after a course of teatment with 60Co γ-rays, the incorporation value in Con A cells became much smaller, the stimulating effect of Con A cells on LPS cells disappeared. LPS cells could not be stimulated by normal Con A cells. The study demonstrated that the radiosensitivity of Con A cells was higher than that of LPS cells

  1. Gamma 60Co-irradiation of organic matter in the Phosphoria Retort Shale

    Science.gov (United States)

    Lewan, M. D.; Ulmishek, G. F.; Harrison, W.; Schreiner, F.

    1991-04-01

    Irradiation experiments were conducted on a thermally immature rock sample of the Phosphoria Retort Shale and its isolated kerogen. A 60Co-source for gamma radiation was employed at dosages ranging from 81 to 885 Mrads, which are attainable by Paleozoic and Precambrian black shales with syngenetic uranium enrichments. Kerogen elemental, isotopic, and pyrolysate compositions are not affected at these dosages, but the bitumens extracted from the irradiated rock are affected. The major effects are reductions in the amounts of bitumen, acyclic isoprenoids, and high-molecular weight acyclic carboxylic acids. Natural differences in the amounts of bitumen and acyclic isoprenoid due to regional and stratigraphie variations in organic source input and depositional conditions make the radiation-induced reductions in these parameters difficult to use as indicators of natural radiation damage in black shales. However, the preferential reduction in the high-molecular weight acyclic carboxylic acids, which are ubiquitous in the living precursory organic matter, is diagnostic of experimental γ-irradiation but may not be diagnostic of natural irradiation. The overall process associated with radiation damage is polymerization by cross-linking through a free radical mechanism. As a result, irradiation of organic matter in black shales is more likely to retard rather than enhance petroleum generation.

  2. Effects of 60Coray irradiation on antioxidant enzyme activities in tobacco

    International Nuclear Information System (INIS)

    Effects of 300Gy 60Coray irradiation on the activities of 3 antioxidant enzymes in tobacco were studied in this paper. The results showed that the activities of superoxide dismutase (SOD), peroxidas (POD) and catalse (CAT) in tobacco were gradually increased. All the activities of SOD POD and CAT reached the maximums at 12 h and then gradually decreased. Similar results were also observed in the expression of sod, pod and cat genes. These results indicated that the activities of antioxidant enzymes could play an important role in tobacco tolerance against irradiation

  3. Evaluation of fruit productivity and quality in Hass avocado submitted to {sup 60}Co gamma radiation; Evaluacion de productividad y calidad de fruta en aguacate Hass sometido a radiacion gamma de {sup 60}Co

    Energy Technology Data Exchange (ETDEWEB)

    Cruz T, E. De la; Ibanez P, J.; Mijares O, P.; Garcia A, J.M. [Instituto nacional de Investigaciones Nucleares, Departamento de Biologia, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1999-07-01

    Evaluation of productivity, postharvest behavior and fruit quality was performed on four years Hass avocado trees irradiated with {sup 60} Co gamma rays in doses of 5, 10, 15, 20 and 25 Gy, established in the ''La Labor'' Experimental Center of the Centro de Investigaciones Cientificas y Tecnologias del Aguacate en el Estado de Mexico (CICTAMEX) at Temascaltepec Mexico. Productivity had a significant increase in the dose of 15 Gy being the average number of fruits nearly 400 % more than the control at fruit setting, being such difference reduced at fruit harvesting to 300 %. In regard to postharvest performance, the respiration index (mg CO{sub 2}/kg/hr) did not show significant differences among treatments. Also others variables such as physiological weight losses, texture, maturity pattern, and sensorial tests (color, flavor, aroma, texture) were not different in regard to the control. This mean that radiation has altered productivity but not the quality and postharvest behavior of fruits. (Author)

  4. Effects of 60Co γ-rays irradiation on seed growth of ground-cover chrysanthemum

    International Nuclear Information System (INIS)

    The seeds of ground-cover chrysanthemum were used to study the effects of different doses of 60Co γ-rays irradiation(10-50 Gy) on seed germination and physiological characteristics. The results showed that the rate of seed germination and seedling survival decreased significantly with the irradiation doses. With the increase of irradiation dose to above 20 Gy, the content of malondialdehyde (MDA) and activity of peroxidase (POD) in seedlings significantly increased. The similar trends were found in the activities of superoxide dismutase (SOD) and glutathione reductase (GR). Catalase (CAT) activity increased at doses lower than 20 Gy, and then decreased at the higher doses, whereas ascorbate peroxidase (APX) activity did not alter except for 40 Gy. It is concluded that the suitable irradiation dose of mutation breeding is 20 Gy for the seeds of ground-cover chrysanthemum. Although 60Co γ-rays irradiation resulted in damage of membrane lipid peroxidation in the survival seedlings, the increased activity of CAT and POD could protect them against the damage. (authors)

  5. Response of avocado genotypes to improvement through {sup 60}Co gamma radiation; Respuesta de diversos genotipos de aguacate al mejoramiento por radiacion gamma de {sup 60}Co

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, E. De la; Rubi A, M.; Garcia A, J.M. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    Ten avocado genotypes were subjected to gamma radiation from 0 to 45 Gy in 1993. Vegetative and reproductive data were analysed in a factorial design. Genotypes differed significative on height and fruit number. Radiation affected significative fruit number but not tree height. ''Hass'' showed strongest interaction between genotype and doses, for fruit number. (Author)

  6. Effects of 60Co gamma radiations on the conduction properties of frog sciatic nerve

    International Nuclear Information System (INIS)

    The effect of Co60 gamma radiations on the amplitude, detection period and duration of the action potential of sciatic nerves of Rana tigrina frogs have been studied. Dose levels of upto 120 kR were employed. Irradiation of the nerves with dose levels upto 30 kR does not seem to affect the action of potential profiles. The amplitude falls rapidly thereafter, registering less than 5% of the original value after irradiation by a dose of 120 kR. Qualitatively similar behaviour is seen in the case of detection period and duration of action potential. These results are examined in the light of data already collected through experiments on the effect of Co60 gamma rays on the enzyme acetyl-cholinesterase (AchE). (author)

  7. Radiosensibilidad de semillas de soya a los rayos gamma 60Co

    Directory of Open Access Journals (Sweden)

    C. de la Fé

    2000-01-01

    Full Text Available El presente estudio se desarrolló en las instalaciones del Instituto Nacional de Ciencias Agrícolas, con el objetivo de evaluar la radiosensibilidad de semillas de soya a los rayos gamma 60Co. Para su ejecución, se seleccionaron e irradiaron muestras de 50 semillas de la variedad Cubasoy-23, las que fueron sembradas en condiciones semicontroladas (macetas en la campaña de primavera, 1997. Las dosis de radiación fueron desde los 50 hasta los 480 Gy, con incrementos de 50 Gy entre las dosis de 50 y 200 Gy e incrementos de 40 Gy entre esta última y la dosis de 480 Gy. Las evaluaciones realizadas consistieron en porcentaje de semillas germinadas a los tres, seis y nueve días de la siembra, altura de las plantas a los 10, 20 y 50 días y número de pares de hojas emitidas a los 10 y 20 días de la siembra. El estudio realizado evidenció la ocurrencia de un efecto fuerte de las dosis aplicadas en el porcentaje de semillas germinadas, resultando las dosis próximas a los 280 Gy las de mayor efecto radioestimulador de la germinación. Desde el punto de vista de la altura de las plantas, el efecto de las dosis aplicadas se correspondió con el descrito para otros materiales biológicos irradiados, caracterizándose este por un aumento a dosis bajas seguido por una reducción cada vez mayor a medida que las dosis aplicadas se incrementaron. Por su parte, la emisión de hojas por las plantas mantuvo un comportamiento en correspondencia con la altura de las plantas. Los resultados del estudio permiten sugerir la aplicación de dosis próximas a los 360 Gy en los trabajos dirigidos a la creación de variabilidad genética en programas de mejora por inducción de mutaciones

  8. Grafting of synthetic polyelectrolyte onto polymer surfaces--comparison of glow discharge and 60Co-gamma-irradiation method

    International Nuclear Information System (INIS)

    Water soluble polyelectrolyte synthesized from natural rubber contains sulfamate and carboxylate groups similar to that of heparin. It is observed that synthetic heparinoid polyelectrolyte is capable of inhibiting blood coagulation. In the present study, we attempted to graft the same onto polystyrene and polymethylmethacrylate surfaces using glow discharge technique and 60Co-gamma-irradiation method, and the surfaces were compared with respect to water contact angle and platelet adhesion parameters. Heparinized surfaces are also evaluated for relative comparison

  9. Polymer microcapsules prepared in inverse emulsion by 60Co γ-ray induced interfacial polymerization

    International Nuclear Information System (INIS)

    Inverse emulsion was usually applied to polymerization of hydrophilic monomers, such as acrylamide, acrylic acid, salt of acrylic acid, and N-isopropylacrylamide. However, there have been few reports of one-step synthesis hydrophobic polymer hollow spheres or microcapsules in inverse emulsion system via an interfacial polymerization approach under mild reaction conditions. The motivation of this work is to explore the formation mechanism of polymer microcapsules via γ-ray irradiation in W/O inverse emulsion system. Utilizing the strong reducing radical (OH, hydrated electron) and oxidant radical (eaq-, hydroxyl radical) produced in aqueous phase by 60Co γ-ray irradiation, two interfacial redox initiation systems were proposed and applied to the preparation of polymer microcapsules. In this work, BPO (benzoyl peroxide)-eaq- and DMA (N, N-dimethyl aniline)-OH were used to control the polymerization position at the water-oil interface. High viscosity of external oil phase, high inner phase emulsion and polymeric surfactant were employed to depress the homogeneous nuclei and enhance stability of the inverse emulsion during polymerization. A typical inverse emulsion of water : Span80: kerosene : styrene = 20ml : 2.0g :10ml/4ml (including 0.050g BPO) was irradiated to 20 kGy by 60Co γ-rays at a dose rate of 65 Gy/min. Finally, polystyrene microcapsules were synthesized successfully with an average diameter of 400 nm and shell thickness of 50 nm. The productivity of micro-capsules decreased with the increasing of styrene content due to the homogeneous nuclei. When cyclohexane was used as the oil phase, porous polymer materials can be successfully obtained. Because of the multiplicity in choosing oil-soluble monomers and substances being dissolved in the aqueous phase, this approach revealed interests in encapsulation of bioactive materials or drugs. (authors)

  10. Effects of 60Co γ-ray irradiation on growth characters of Chamaecrista seeds

    International Nuclear Information System (INIS)

    The seeds of 5 Chamaecrista varieties were irradiated by 60Co γ-ray of 300 Gy and the effects on M1 generation were studied. The results showed that the emergence of 5 Chamaecrista varieties decreased in some degree ; the stem-length of variety 34721 was significantly decreased, the stem-diameter of variety 2219 and the leaf-width of variety 2219 were significantly increased. The number of branch, leaf and leaf-length had no significant difference, but there were many black blots in the leaf during early period; the dry-weight of aerial part changed in two directions, either increased (92985) or decreased (34721). The total N of variety 2217 were significantly increased and the total P of variety 92985 were significantly decreased. The squaring stage, initiate flower stage, full bloom stage, pod-bearing stage, peak pod setting stage and maturing stage had changed in two direction, either early, or late

  11. Dominant lethal effect of gamma radiation of 60Co in Biomphalaria glabrata (SAY, 1818)

    International Nuclear Information System (INIS)

    Germ cell mutations are used in ecotoxicological studies as biomarkers of population effects and indicators of ecological changes. Biomphalaria glabrata, a freshwater mollusk, is a good experimental model for biomonitoring studies due to its biological characteristics and the ecological importance of this invertebrate group. The dominant lethal test was established in B. glabrata for the detection of germ cell mutations. Results with chemical mutagens showed that this system is efficient, specific and sensitive in the evaluation of germ cell mutations induced by reference mutagens. In this work, the dominant lethal effects of gamma radiation of 60Co were studied. A preliminary experiment was done to establish the dose range and to estimate the chronology of spermatogenesis in B. glabrata. This estimate is possible because of the uniformity in response to ionizing radiation between germ cells at homologous stages of spermatogenesis in widely different species. In general, pre-meiotic germ cells are less sensitive to the induction of lethal dominant mutations than post-meiotic cells. This effect can be attributed to: young gametogenic cells - mitotically active - have greater repair ability from sub-lethal DNA damage and there is a selective elimination of the damaged cells. In our system: induction of lethal dominant mutations causes an increase in the frequency of malformations and, cytotoxic effect is displayed as a reduction in the crossing rates. Total duration of spermatogenesis was estimated in approximately 36 days, with the following distribution of stages: 1 to 13 days - spermatogonia, 14 to 20 days - spermatocytes, 21 to 36 days - spermatids and spermatozoa. Based on this chronology, irradiated wild-type snails with 2,5; 10 and 20Gy and crossed with non-irradiated albino snails after 7, 17, 23, 30 and 36 days. The frequencies of malformations in the heterozygous wild-type offspring of the nonirradiated albino snails were used as indicator of germ cell

  12. Decomposition of ρ-nonylphenols in water by 60Co γ-ray irradiation

    International Nuclear Information System (INIS)

    ρ-Nonylphenols (NPs), one of endocrine disrupting chemicals, are used as plastic flexibilizers or nonionic surfactants, and widely released into the water environment. Hydroxyl radicals produced from water molecules by γ-ray irradiation have high oxidation reactivity. Recently, treatments with the hydroxyl radicals have drawn much attention to conserve the water environment. In this study, decompositions of NPs in water were investigated using hydroxyl radicals by 60Co γ-rays irradiation. The concentrations of the NPs at initial concentration from 45 to 1000 nM were decomposed by γ-ray irradiation. Qualitative and quantitative analyses of NPs were carried out by high performance liquid chromatography. The decomposition curves of NPs at each initial concentration were analyzed as single exponential functions. Alkylphenol activity of aqueous NPs solution, which was estimated by enzyme-linked immunosorbent assay, implies the irradiation products have alkylphenol activity. Two products having molecular weight of 236 were investigated by liquid chromatography-mass spectrometry, and were considered to be ρ-nonylcatechol and 1-(ρ-hydroxyphenyl)-1-nonanol on the basis of the oxidation mechanisms of ρ-cresol and 4-ethylphenol. (author)

  13. Study on the energy dependence of gamma radiation detectors for {sup 137}Cs and {sup 60}Co; Estudo da dependencia energetica de detectores de radiacao gama para {sup 137}Cs e {sup 60}Co

    Energy Technology Data Exchange (ETDEWEB)

    Nonato, Fernanda B.C.; Diniz, Raphael E.; Carvalho, Valdir S.; Vivolo, Vitor; Caldas, Linda V.E., E-mail: fbnonato@ipen.b, E-mail: rediniz@ipen.b, E-mail: vcsouza@ipen.b, E-mail: vivolo@ipen.b, E-mail: lcaldas@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    38 Geiger-Mueller radiation detectors and 9 ionization chambers were calibrated, viewing to study the energy dependence of the monitor response for gamma radiation fields ({sup 137}Cs and {sup 60}Co). The results were considered satisfactory only for ionization chambers and for some Geiger-Mueller detectors

  14. Effects on agronomic traits of M1 by pollen of upland cotton irradiated by 60Coray

    International Nuclear Information System (INIS)

    [Objective] The aim was to provide reference for research on radiation and breeding of cotton pollen through irradiating common ripe pollen grain of upland cotton by 60Co-? Ray of varied doses. [Method] Ripe pollen grains of upland cotton were irradiated by 60CoRay with doses of 5, 10, 15, and 20 Gy, respectively, to learn radiation effect and select appropriate dose. [Result] Most properties of M1 obviously showed variation when dose was over 10 Gy; vitality, growth, and fertility were greatly inhibited when dose was 15 Gy which was almost semi-lethal concentration, and variation species were richest at the same time, which provided materials for practical breeding. [Conclusion] 60CoRay of 15 Gy was more suitable for inducing research for ripe pollen grains of upland cotton

  15. Protective effect of gingerol on leucocyte and bone marrow DNA of 60Co γ-rays irradiated mice

    International Nuclear Information System (INIS)

    In this article, the effect of gingerol on peripheral leucocyte and bone marrow DNA of 60Co γ-rays irradiated mice was developed., Twenty-four healthy healthy female Kunming mice were randomly divided into 4 groups: control, gingerol, irradiation and gingerol + irradiation group. Gingerol group and gingerol + irradiation group were given gingerol intragastrically once a day for five days. Irradiation group and gingerol + irradiation group were suffered from 5 Gy 60Co γ-rays irradiation at the rate of 1.2 Gy/min on the 6th day. Blood samples, spleens, livers and thigh bones were collected to be measured after 48 h. The results showed that, compared with irradiation group, gingerol + irradiation group had significantly higher spleen index (p60Co γ-rays irradiated mice. (authors)

  16. Mechanism of INF-γ antagonizing pulmonary fibroblast proliferation stimulated by 60Co γ-rays

    International Nuclear Information System (INIS)

    Objective: To explore the mechanism of IFN-γ antagonizing human pulmonary fibroblasts (HLF) proliferation stimulated by 60Co γ-rays. Methods: The time- and dose-effect of HLF proliferation promoted by TGF-β1 and rat serum after radiation as well as effect of IFN-γ on proliferation were observed by MTT colorimetric methods. Content of TGF-β1 in rat serum and pulmonary tissues after irradiation as well as the effect of IFN-γ on rat serum after radiation promoting HLF to synthesize TGF-β1 were determined by ELISA. Results: TGF-β1 played a role in promoting HLF proliferation. The sera of irradiated rats could promote HLF proliferation and TGF-β1 synthesis, but the effect was inhibited by IFN-γ significantly (P<0.05). The level of TGF-β1 in rat serum and lung tissues gradually increased from 1 to 4 weeks after irradiation. Conclusions: TGF-β1 is involved in the process of γ-rays stimulating HLF proliferation, while IFN-γ can inhibit HLF from synthesizing TGF-β1 and antagonize its role of promoting HLF proliferation. (authors)

  17. Effects of 60Co γ rays on the cell cycle progress of MCF-7 cells

    International Nuclear Information System (INIS)

    To investigate the effects of ionizing radiation on cell cycle progress of tumor cell lines, the human breast cancer MCF-7 cell line cultured in vitro was exposed to 60Co γ rays and the alterations in cell cycle progress after irradiation were measured by flow cytometry. The results indicated that the MCF-7 cells showed a transient S arrest continuing for about 6 h and an obvious G2 arrest continuing for about 63 h after irradiation with 5.0 Gy γ rays. S and G2 arrest culminated at 9 h and 18 h respectively after irradiation and the peak values of S and G2 arrest reached respectively 1.6 times and 6.2 times as many as normal value. The dose-effect curve examined 9 h after irradiation was quite different from that examined 18 h after irradiation. Both of the S arrest at 9 h after irradiation and the G2 arrest at 18 h after irradiation presented significant relationship with irradiation dose

  18. Modification of polyethersulfone films by grafting hydrophilic monomers with 60Co γ-rays

    International Nuclear Information System (INIS)

    Polyethersulfone (PES), with its high strength, high temperature resistance, corrosion- resistance, oxidation resistance and applicability under wide pH range, is used extensively as ultrafiltration and nanofiltration membrane. However, PES membranes foul easily in such an application because of hydrophobic nature of PES raw materials. Improving the hydrophilicity of PES by grafting hydrophilic monomers onto it is of potential to solve the problem. At present, common approaches to improve hydrophilicity of PES membranes are UV grafting modification, plasma modification, and chemical modification, whereas grafting and modifying PES films by 60Co γ-rays has rarely been reported. Studies have been carried out in our laboratory to graft hydrophilic monomers onto PES membranes directly or PES powders via simultaneous radiation grafting with the rays. Acrylic acid, methyl acrylic acid or acrylamide was used to study effects of the monomer concentration, irradiation dose and dose rate, solvent, inhibitor and pH of the grafting solution on the degree of grafting. The results showed that hydrophilicity of all the PES membranes could be improved, with the extent of improvement being dependent on the grafting conditions. (authors)

  19. Comparisons of the standards for air kerma of the PTB and the BIPM for {sup 60}Co and {sup 137}Cs gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Allisy-Roberts, P.J.; Burns, D.T. [Bureau International des Poids et Mesures (BIPM), 92 - Sevres (France); Buermann, L.; Kramer, H.M. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

    2005-11-15

    Direct comparisons of the standards for air kerma of the Physikalisch-Technische Bundesanstalt (PTB, Germany) and of the Bureau International des Poids et Mesures (BIPM) were carried out in the {sup 60}Co and {sup 137} Cs radiation beams of the BIPM in 2000. The results, expressed as ratios of the PTB and the BIPM standards for air kerma, indicate a relative difference in {sup 60}Co of 9.9 x 10{sup -3} with a combined standard uncertainty of 1.8 x 10{sup -3}, and in {sup 137}Cs of 6.4 x 10{sup -3} with a combined standard uncertainty of 2.8 x 10{sup -3}. The earlier comparisons in {sup 60}Co {gamma} rays made in 1971 (direct) and 1989 (indirect) resulted in an agreement of the two standards within 2 x 10{sup -3}. The differences obtained now are due to the application of new correction factors for wall effects and point source non-uniformity of the beam, k{sub wall} and k{sub pn}, for the PTB standards, which were calculated using Monte Carlo methods. (authors)

  20. A prototype of an ionization chamber for gamma radiation beams of 60Co: Experimental and Monte Carlo preliminary results

    International Nuclear Information System (INIS)

    Ionization chambers are the most widely used instruments for dosimetry in radiotherapy. With the aim to test new configurations and materials using low-cost and easily-available components, verify the possibility of its application in the gamma radiation field of 60Co and fulfill the need of a chamber for scientific metrological purposes, in this paper the prototype of a plane-parallel ionization chamber has been designed and built, and its performance has been studied at the SSDL of KARAJ. The front wall and back wall of the chamber were made of graphite and Plexiglas respectively, as opposed to the one type of material in commercially available chambers. The collecting electrode has a diameter of 20 mm. The sensitive volume is 0.63 cm3. It was found that the Leakage current, the short-term stability and the polarity effect were within the international recommendations. The results were compared with those of a reference cylindrical chamber. The maximum difference observed in this comparison was 1.1%. The relative uncertainty was below 0.2%. Moreover, Monte Carlo simulation was undertaken using MCNP4C code and the relative difference of 1.9% was observed compared to the experiment. As a result the chamber presented a satisfactory performance in all evaluated tests in Gamma radiation field of 60Co. -- Highlights: • The prototype of a plane-parallel Ionization Chamber was designed. • Its performance was studied in Gamma radiation field of 60Co. • The response of the chamber was measured and compared with that of the cylindrical ionization chamber. • The chamber was simulated using the MCNP4C Monte Carlo code. • The Leakage current, the short-term stability and the polarity effect were within the international recommendations

  1. 100 Gy 60Co γ-Ray Induced Novel Mutations in Tetraploid Wheat

    Directory of Open Access Journals (Sweden)

    Chuntao Yang

    2014-01-01

    Full Text Available 10 accessions of tetraploid wheat were radiated with 100 Gy 60Co γ-ray. The germination energy, germination rate, special characters (secondary tillering, stalk with wax powder, and dwarf, meiotic process, and high-molecular-weight glutenin subunits (HMW-GSs were observed. Different species has different radiation sensibility. With 1 seed germinated (5%, T. dicoccum (PI434999 is the most sensitive to this dose of radiation. With a seed germination rate of 35% and 40%, this dose also affected T. polonicum (As304 and T. carthlicum (As293. Two mutant dwarf plants, T. turgidum (As2255 253-10 and T. polonicum (As302 224-14, were detected. Abnormal chromosome pairings were observed in pollen mother cells of both T. dicoccoides (As835 237-9 and T. dicoccoides (As838 239-8 with HMW-GS 1Ax silent in seeds from them. Compared with the unirradiated seed of T. polonicum (As304 CK, a novel HMW-GS was detected in seed of T. polonicum (As304 230-7 and its electrophoretic mobility was between 1By8 and 1Dy12 which were the HMW-GSs of Chinese Spring. These mutant materials would be resources for wheat breeding.

  2. Studies on mutagenic activity of 60Co γ-ray irradiated rape pollen

    International Nuclear Information System (INIS)

    In the present study on disinfection, the rape pollen was irradiated with 2.5 kGy 60Co γ-ray. Micronuclei, sister chromatid exchanges (SCE) of bone marrow cells and chromosomal aberrations of meiotic cells in mice were used as an indicater of chromosomal damage to study the mutagenicity of irradiated rape pollen. The results are as follows: (1) The frequency of micronuclei in polychromatic erythrocytes is 2.00 per mille; nucleated cells is 0.8 per mille in control group. In the numbers of polychromatic erythrocytes and nucleated cells with micronuclei, there is no obviously difference in irradiated and unirradiated groups. (2) SCE incidence of control group is 2.01 ± 0.12/cell. No significant difference in the frequency of SCE exists between non-irradiated rape pollen and the control groups. But the frequency of SCE in irradiated rape pollen group (3000 mg/kg/day x 7) is 2.36 ± 0.12/cell; high dose group (6000 mg/kg/day x 7) is 2.96 ± 0.14/cell. In comparison with control group, there is a significant difference. (3) The chromatid breaks, fragments, and univalents in primary spermatocytes have been obseved. The frequencies of chromosomal aberration showed no obviously difference among irradiated and non-irradiated rape pollen groups

  3. Protective effect of catecholestrogens against 60Co γ-ray radiation injury in mice

    International Nuclear Information System (INIS)

    When 10-week-old male BALB/c mice received whole-body irradiation with a single dose of 8 Gy 60Co γ-ray and catecholestrogen 2-hydroxyestradiol (2-OHE2) was subcutaneously injected 3 hours before and after the irradiation, 30-day survival rate of the mice was 70%, while the survival rate of the mice administered the other test samples was as follows; 2-hydroxyestrone, 20%; 2-hydroxyestriol, 20%; 4-hydroxyestradiol, 0%; 2-methoxyestrone, 0%; 2-methoxyestradiol, 0%; 2-methoxyestriol, 0%; estrone, 0%; estradiol, 5%; estriol, 0%; control, 5%. Lipid peroxide level in the liver of mice markedly increased on the 4th day after the irradiation. However, this increase in the lipid peroxide level was significantly suppressed by the administration of 2-OHE2. The radiation-induced anemia, leukopenia, and atrophy of the thymus were significantly protected by the administration of 2-OHE2. These results indicate that 2-OHE2 had a potent inhibitory effect on radiation injury. (author)

  4. Impact of 60Co-γ-ray Sterilization of Tetracycline Hydrochloride Raw Materials%60Co-γ射线对盐酸四环素原料灭菌的研究

    Institute of Scientific and Technical Information of China (English)

    黄波; 赵全如; 刘莉萍

    2014-01-01

    Different doses of 60Corays were compared for radiation sterilization on raw materials of tetracycline hydrochloride. By checking stability data, the optimal radiation dose of 60Corays on tetracycline hydrochloride raw materials was 9 kGy, at which its physical and chemical detection indicators were in line with the requirements of USP, and the sterility test results met the requirements..%采用不同剂量的60Co-γ射线对盐酸四环素原料进行辐射灭菌,结合稳定性考察数据,最终确定盐酸四环素原料的60Co-γ射线的辐射剂量为9 kGy时,其理化检测指标符合USP的要求,且无菌检查符合要求。

  5. Effects of (60)Co gamma irradiation on behavior and gill histoarchitecture of giant fresh water prawn Macrobrachium rosenbergii (DE MAN).

    Science.gov (United States)

    Stalin, A; Broos, K V; Sadiq Bukhari, A; Syed Mohamed, H E; Singhal, R K; Venu-babu, P

    2013-06-01

    Present study was designed to observe the effects of (60)Co gamma radiation in behavioral and histological changes in the gills of giant fresh water prawn Macrobrachium rosenbergii. The adult prawns were irradiated with four different dose levels (3mGy, 30mGy, 300mGy and 3000mGy) and the control group (without irradiation) was maintained separately. Behavioral changes like hyperactivity, loss of balance, reduced swimming rate, slower rate of food intake and convulsions were observed in higher dose levels of 300mGy and 3000mGy. The histological alterations such as accumulated haemocytes in haemocoelic spaces, abnormal gill tips, lifted lamellar epithelium, swollen and fused lamellae, hyperplasic, necrotic, clavate-globate and complete disorganization of lamellae were observed in (60)Co gamma irradiated prawns. Significantly more considerable histological alterations were observed in the highest dose level of 3000mGy, but no mortality was evidenced. This study serves as biomonitoring tool to assess the radiation pollution in the aquatic environment.

  6. Use of {sup 60}Co gamma radiation in increased levels of total polyphenol extracts of bark of Schinus terebinthifolius Raddi

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Gustavo H.F.; Silva, Edvane B.; Silva, Hianna A.M.F.; Amorin, Elba L.C.; Peixoto, Tadeu J.S.; Yara, Ricardo; Lima, Claudia S.A., E-mail: santosghf@hotmail.com, E-mail: edvborges@yahoo.com, E-mail: amdemelo@hotmail.com, E-mail: claudia.salima@gmail.com, E-mail: ricardo.yara@gmail.com, E-mail: tadeu1903@yahoo.com.br, E-mail: elba@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2013-07-01

    Schinus terebinthifolius Raddi (Anacardiaceae) is well known as sources of phenolic compounds. Known as mastic pepper, red pepper tree is a plant native to midsize coast of Brazil. Some of its structures have proven antibacterial, anti-inflammatory, antifungal and healing. The aim of this study was to evaluate the difference in the phenol contents of crude extracts that were measured after irradiating the barks of S. terebinthifolius using gamma radiation from {sup 60}Co. The crude extract were divided into a control group and eight experimental groups, which were separated based on the doses of gamma radiation to which they were exposed: 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 20.0 and 50.0 kGy (Assays were performed in triplicate). The results allow observe that gamma radiation promoted in extracts of bark of S. terebinthifolius, many percents increase (p> 0.05) of total polyphenol content between 2.5 kGy (41.93%) and 50.0 kGy (44.52%) compared to 0 kGy (30.07%), with the same gradual to 10.0 kGy, and reaching peak maximum at 10.0 kGy (68.44%). However, the study puts the process of gamma radiation from {sup 60}Co as an alternative significant increase in the percentage of some natural substances of plant material, and subsequently contribute to the augmentation of various therapeutic applications to which they are assigned. (author)

  7. Morphological and histological studies on freshwater prawn Macrobrachium rosenbergii (de man) irradiated with {sup 60}Co gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Stalin, A.; Broos, K.V. [P.G. and Research Department of Zoology, Jamal Mohamed College (Autonomous), Tiruchirappalli 620020, Tamil Nadu (India); Sadiq Bukhari, A., E-mail: abjmc@yahoo.in [P.G. and Research Department of Zoology, Jamal Mohamed College (Autonomous), Tiruchirappalli 620020, Tamil Nadu (India); Syed Mohamed, H.E. [P.G. and Research Department of Zoology, Jamal Mohamed College (Autonomous), Tiruchirappalli 620020, Tamil Nadu (India); Singhal, R.K. [Analytical Spectroscopy Section, Analytical Chemistry Division, Bhabha Atomic Research Center, Trombay, Mumbai 4000085 (India); Venu-Babu, P. [Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Center, Trombay, Mumbai 4000085 (India)

    2013-11-15

    Graphical abstract: -- Highlights: •Analyzing the impact of {sup 60}Co gamma radiation (low doses) in M. rosenbergii. •LD{sub 50} identified in 30 Gy; Irradiated exhibits morphological changes than control. •Significantly decreased HSI and histological changes in irradiated groups. •Aberration severities increased as increased of dose level. •Biomonitoring tool in determining low dose radiation pollution in aquatic ecosystem. -- Abstract: This study was framed to investigate the {sup 60}Co gamma radiation induced morphological and histological variations in freshwater prawn Macrobrachium rosenbergii. The LD{sub 50} value of {sup 60}Co gamma irradiated M. rosenbergii observed (by probit analysis) at 30 Gy. Prawns were irradiated to four different dose levels (3 mGy, 30 mGy, 300 mGy and 3000 mGy) using Theratron Phoenix TeleCobalt Unit [P-33] and one control group (without irradiation) maintained separately. Irradiated groups exhibited several morphological variations such as discoloration; damaged rostrum; opaque coloration in cephalothorax; black bands and dot formation in abdomen; deformed uropods and telson in tail regions when compared with control group. The Hepato Somatic Index reflected the severity of radiation on hepatopancreas. Histological variations in gills, hepatopancreas and muscles of irradiated groups were observed. In gills, structural changes such as swollen and fused lamellae, abnormal gill tips, hyperplasic, necrotic and clavate-globate lamellae were observed in gamma irradiated prawns. Accumulation of hemocytes in hemocoelic space, interstitial sinuses filled with abnormal infiltrated hemocytes, the tubular epithelium with ruptured basal laminae, abnormal and coagulated lumen, necrotic tubules, thickened basal laminae, tissue debris, necrotic hepatocytes were observed in irradiated prawn hepatopancreas. In muscle, shrinkage of muscular fiber and necrotic musculature were observed in irradiated prawns. These structural alterations of

  8. Evaluation of gamma-sterilization ({sup 60}Co) by RT-PCR by DHFR expression detection

    Energy Technology Data Exchange (ETDEWEB)

    Converso, Ana Paula G.; Andrade Junior, Heitor F. de [Instituto de Medicina Tropical de Sao Paulo, Sao Paulo, SP (Brazil)]. E-mail: anapaulagconverso@gmail.com; hfandrad@usp.br; Vieira, Daniel P. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Instituto de Medicina Tropical de Sao Paulo, Sao Paulo, SP (Brazil); E-mail: dperezv@usp.br

    2007-07-01

    The improvement of techniques to detect pathogen agents in blood had reduced significantly the contamination mechanisms by hemocomponents in blood transfusion procedures. Ionizing radiation is a method that has presented several applications on medicine and in currently days has been showing special attention on blood banks which has been applied to avoid TA-GVHD development. DHFR is an enzyme constitutive in Plasmodium protozoa and has an important role in folate metabolism on these parasites. Detecting the expression of RNAm coder for this enzyme is possible to evaluate the viability of this parasite in blood samples. Plasmodium chabaudi AJ is a parasite that induces lethal malaria in rodents similar to human malaria In this work, the objective was to detect the presence of plasmodium protozoa in irradiated blood samples, infected experimentally, through the application of a RT-PCR using primers for the coder sequence of DHFR's mRNA. We studied doses of ionizing radiation between 0 and 75 Gy. The irradiation procedures were accomplished in Center of Radiation Technology of IPEN-CNEN in a {sup 60}Co panoramic source. Our results had demonstrated that RT-PCR is a sensible method to evaluate the viability of plasmodium in blood samples because the technique could detect low parasite burden in all tested samples. (author)

  9. Effects of 60Co gamma radiation on defense function of human polymorphonuclear leukocytes

    International Nuclear Information System (INIS)

    The effects of radiation on defense function of polymorphonuclear leukocytes (PMN) were studied following irradiation with 60Co γ radiation (30 - 3,000 rad) using PMN separated from the peripheral blood of healthy volunteers. The migration distances for all three measures of chemotaxis to fMet-Leu-Phe (10-8 M), chemokinesis induced by fMet-Leu-Phe, and random migration tended to decrease with increasing dose, showing 0.0054 μm/rad (p -5 M) in conjunction with cytochalasin B (CB, 5 μg/ml) there was a significant dose trend, showing the dose effects of decreasing 0.0022 % release/rad for BGL and 0.0030 % release/rad for LYZ with increasing dose. In superoxide anion (O2-) production, a slight and marginally significant linear dose trend was found. These results suggest that the defense function of PMN is not so resistant to radiation as predicted from the fact that PMN in the peripheral blood are differentiated and mature. It is thought that radiation inflicts substantially harmful effects on the defense function of peripheral PMN. (author)

  10. Morphological and histological studies on freshwater prawn Macrobrachium rosenbergii (de man) irradiated with (60)Co gamma radiation.

    Science.gov (United States)

    Stalin, A; Broos, K V; Sadiq Bukhari, A; Syed Mohamed, H E; Singhal, R K; Venu-Babu, P

    2013-11-15

    This study was framed to investigate the (60)Co gamma radiation induced morphological and histological variations in freshwater prawn Macrobrachium rosenbergii. The LD50 value of (60)Co gamma irradiated M. rosenbergii observed (by probit analysis) at 30 Gy. Prawns were irradiated to four different dose levels (3 mGy, 30 mGy, 300 mGy and 3,000 mGy) using Theratron Phoenix TeleCobalt Unit [P-33] and one control group (without irradiation) maintained separately. Irradiated groups exhibited several morphological variations such as discoloration; damaged rostrum; opaque coloration in cephalothorax; black bands and dot formation in abdomen; deformed uropods and telson in tail regions when compared with control group. The Hepato Somatic Index reflected the severity of radiation on hepatopancreas. Histological variations in gills, hepatopancreas and muscles of irradiated groups were observed. In gills, structural changes such as swollen and fused lamellae, abnormal gill tips, hyperplasic, necrotic and clavate-globate lamellae were observed in gamma irradiated prawns. Accumulation of hemocytes in hemocoelic space, interstitial sinuses filled with abnormal infiltrated hemocytes, the tubular epithelium with ruptured basal laminae, abnormal and coagulated lumen, necrotic tubules, thickened basal laminae, tissue debris, necrotic hepatocytes were observed in irradiated prawn hepatopancreas. In muscle, shrinkage of muscular fiber and necrotic musculature were observed in irradiated prawns. These structural alterations of the organs it is felt could affect the vital physiological functions such as respiration, osmotic and ionic regulation in gills and muscles; absorption, storage and secretion of the hepatopancreas which in turn could adversely affect the growth and survival of freshwater prawn M. rosenbergii.

  11. Biological changes in Musca domestica L., 1758 (Diptera:Muscidae), induced by gamma radiation (60 Co)

    International Nuclear Information System (INIS)

    This work was carried out in the Entomology Section of the Centre of Nuclear Energy in Agriculture (CENA), University of Sao Paulo, Piracicaba, Sao Paulo, Brazil. The objective of the present research work was to investigate some effects of gamma radiation on the various stages of M. domestica life cycle. (author)

  12. Response of avocado genotypes to improvement through 60Co gamma radiation

    International Nuclear Information System (INIS)

    Ten avocado genotypes were subjected to gamma radiation from 0 to 45 Gy in 1993. Vegetative and reproductive data were analysed in a factorial design. Genotypes differed significative on height and fruit number. Radiation affected significative fruit number but not tree height. ''Hass'' showed strongest interaction between genotype and doses, for fruit number. (Author)

  13. Radiation-induced micronucleus formation in mice bone marrow after exposure to different doses of 60Co gamma radiation

    International Nuclear Information System (INIS)

    The frequency of micronuclei formation in the polychromatic erythrocytes and normochromatic erythrocytes was studied at 12 and 24th post-irradiation in mice bone marrow whole-body exposed to 0, 0.5, 1.0, 2.0, 3.0 and 4.0 Gy of 60Co gamma radiation. It was observed that the frequency of MPCE (micronucleated polychromatic erythrocytes) and MNCE (micronucleated normochromatic erythrocytes) increased with increase in exposure dose in both intervals studied. The data analyzed using the linear quadratic (Y+C+αD+βD2) equation. It was found that the data for MPCE and MNCE fitted best for linear quadratic model. (The PCE/NCE ratio declined with increase in exposure dose in both intervals and this decline was dose related. (author). 28 refs., 1 tab

  14. Gamma-ray methods

    International Nuclear Information System (INIS)

    Bulk analysis techniques using gamma radiation are described. The methods include gamma-ray induced reactions, selective gamma-ray scattering and methods which rely on natural radioactivity. The gamma-ray resonance scattering technique can be used for the determination of copper and nickel in bulk samples and drill cores. The application of gamma-gamma methods to iron ore analysis is outlined

  15. Radiation effects of 60Co γ-rays on expression of CDKN1A mRNA in human lymphocytoblast

    International Nuclear Information System (INIS)

    Objective: To study effect of 60Co γ-rays radiation with different doses on expression of CDKN1A gene mRNA in human lymphocytoblast cultured for different time. Methods: After human lymphocytoblasts were irradiated by the 60Co γ-rays with various doses of 0, 0.2, 1, 3, 5 and 10 Gy, and cells were separately cultured for sustaining survival during 0, 4, 24, 48, 72 and 96 h. The total RNA was extracted from each sample and the real-time PCR was conducted to observe the gene CDKN1A mRNA level changes in lymphocytoblasts exposed to various radiation doses for various cultured time. Results: Expressive levels of the CDKN1A mRNA in lymphocytoblasts gradually went up with increasing radiation doses, which showed γ-rays dose dependent from 0 Gy to 5 Gy (P<0.05), and reach the peak when cells were cultured for 24 h after exposing to radiation while displayed an expressive downtrend during the later stage of cell culture. Conclusion: Increase of the CDKN1A mRNA expression level in human lymphocytoblasts after exposing to 60Co γ-rays radiation within 24 hours of culture shows a dose dependent way, which may be used to evaluate the ionizing radiation dose. (authors)

  16. Radioprotective effects of sodium tungstate on hematopoietic injury by exposure to 60Co γ-rays in Wistar rats

    International Nuclear Information System (INIS)

    Radioprotective effects of sodium tungstate (ST) on 60Co γ-ray induced decrease in hematocrit value and in survival rate in Wistar strain male rats were examined. A long term administration of ST (less than 150 mg/kg body weight/day) for 60-300 day had no significant effects on body and organs weights and survival days. The LD50/60 in 20 weeks old rats was 220 mg/kg body weight/day. Daily administration of 38, 75 or 150 mg from 7 days before and after irradiation to 60 days significantly mitigated the decrease in hematocrit values, especially at 23 days after irradiation (P60Co γ-rays significantly. The dose-reduction factor for survival of 38 mg ST administered rats was 1.14. (author)

  17. Effect of 60Co γ-rays irradiation pretreatment on callus inductivity and differentiation of strawberry anther

    International Nuclear Information System (INIS)

    Strawberry buds, in which a majority of pollen had single nuclear keeping to the side, were pretreated by 60Co γ-rays irradiation at different doses. The irradiation effect on the callus inductivity and plant differentiation rate of strawberry anther were studied. The results indicated that the pretreatment by 60Co γ-rays could increase the anther callus inductivity and plant differentiation rate significantly, and 20 Gy was the best dose. The callus inductivity of Akihime and Toyonoka increased by 39.09% and 35.68%, respectively, compared with the no-pretreatment materials. On the same media, the plant differentiation rate of Akihime and Toyonoka were also increased by 6.67%-6.72% and 4.73%-6.45%, respectively, compared with the two varieties of no-pretreatment. (authors)

  18. The Effect of 60Co Gamma Irradiation on Various Fractions of Human Blood-Plasma Proteins

    International Nuclear Information System (INIS)

    The potential usefulness of employing ionizing radiation to cold-sterilize biomedical products has stimulated interest in characterizing the radiation sensitivity of various biologicals like vitamins, antibiotics, enzymes, antibodies and blood plasma fractions. This report presents findings on the sensitivity of haemagglutinin activity in human sera exposed to cobalt-60 gamma radiation. At doses tested between 0.2 and 5.0 Mrad, α-isohaemagglutinins were found to be more readily inactivated than ß-isohaemagglutinins, but neither was completely inactivated in this range. Sterility, clotting and antihaemophilic activity were also assessed on irradiated and freeze-dried preparations of human plasma with no significant differences in response detected. (author)

  19. Cutaneous mitochondrial protection by topical treatment of herbal antioxodiants following 60 Co-gamma irradiation

    International Nuclear Information System (INIS)

    To find out the effective dose of herbal antioxidants to elevate the cutaneous lipid peroxidation (LP) at optimal level, gamma irradiation of cutaneous microsomal fraction was performed at different doses and 200 Gy was chosen. The present findings indicate that the failure of succinate in suppression of mitochondrial LP of irradiated rats might be due to diminishing of mitochondrial antioxidants which had been reduced by free radicals (generated by irradiation), since succinate suppressed mitochondrial LKP in antioxidant-treated rats. From these points of view, topical application of either curcumin or ellagic acid could be beneficial in prevention of radiation skin cancer

  20. Use of 60 Co gamma radiation to expend the shell life of packaged sliced loaves

    International Nuclear Information System (INIS)

    The evaluation of conservation of sliced loaves (bread cut into slices). baked by five bakeries of Piracicaba, after gamma irradiation and maintained into polyethylene begs of low density, of 47,5 and 85 μm of thicknesses is shown. The sliced loaves were put into the bags and thermo-sealed by hand, like they were handled by the bakers. After this, they were irradiated with doses of 0.0: 2.0; 4.0; 6.0; 8.0 and 10.0 kGy of gamma radiation in a irradiation chamber of Cobalt-60 at a dose rate of 2,68 kGy per hour, at the room temperature (280 C). After irradiation the samples were maintained under at the room temperature (26 - 340 C), and humidity, as similar as possible to the conditions of the markets, bakeries and shops they were sold. The samples were evaluated every days and if any of them presented sign of contamination. It was threw away because it was inappropriate for human consumption. (author)

  1. Effect of gamma radiation (60Co) on the growth of Aspergillus ochraceus coffee (Coffea arabica L.)

    International Nuclear Information System (INIS)

    Coffee is a major product on the world market. Its acceptance depends strongly on the sensory characteristics of the beverage, that is its aroma and flavor. One of the most important aspects of coffee culture today is the cup quality as such all segments of coffee production network are concentrating efforts to improve this trait. Foods that have been contaminated with fungi may contain may produce many mycotoxins including ochratoxim A (OTA). To prevent OTA in foodstuffs, it is necessary detect the producing fungi early. Ionizing radiation is a safe, environmentally clean, energy efficient process that can be used to increase the quality and reducing the microbiological contamination of the coffee. The aim of the present study was to evaluate the effects of different gamma radiation doses (0.0, 6.0, 12.0 and 18.0 kGy) on the growth of Aspergillus ochraceus in coffee (Coffee arabica L.). The analysis were performed to determine the fungi contamination the results were expressed as the viable counts per gram of sample (CFU/g) coffee samples irradiated and unirradiated. The results shows that microbiological contamination of coffee disagrees when increase doses of irradiation. The radiation doses 6.0, 12.0 and 18.0 kGy used resulted in a elimination of the number of Aspergillus ochraceus CFU/g when compared to the nonirradiated control group. Under the present conditions, gamma radiation was found to be an alternative for the control of Aspergillus ochraceus. (author)

  2. Combined reactor neutron beam and 60Co γ-ray radiation effects on CMOS APS image sensors

    Directory of Open Access Journals (Sweden)

    Zujun Wang

    2015-02-01

    Full Text Available The combined reactor neutron beam and 60Co γ-ray radiation effects on complementary metal-oxide semiconductor (CMOS active pixel sensors (APS have been discussed and some new experimental phenomena are presented. The samples are manufactured in the standard 0.35-μm CMOS technology. Two samples were first exposed to 60Co γ-rays up to the total ionizing dose (TID level of 200 krad(Si at the dose rates of 50.0 and 0.2 rad(Si/s, and then exposed to neutron fluence up to 1 × 1011 n/cm2 (1-MeV equivalent neutron fluence. One sample was first exposed to neutron fluence up to 1 × 1011 n/cm2 (1-MeV equivalent neutron fluence, and then exposed to 60Co γ-rays up to the TID level of 200 krad(Si at the dose rate of 0.2 rad(Si/s. The mean dark signal (KD, the dark signal non-uniformity (DSNU, and the noise (VN versus the total dose and neutron fluence has been investigated. The degradation mechanisms of CMOS APS image sensors have been analyzed, especially for the interaction induced by neutron displacement damage and TID damage.

  3. Combined reactor neutron beam and 60Co γ-ray radiation effects on CMOS APS image sensors

    International Nuclear Information System (INIS)

    The combined reactor neutron beam and 60Co γ-ray radiation effects on complementary metal-oxide semiconductor (CMOS) active pixel sensors (APS) have been discussed and some new experimental phenomena are presented. The samples are manufactured in the standard 0.35-μm CMOS technology. Two samples were first exposed to 60Co γ-rays up to the total ionizing dose (TID) level of 200 krad(Si) at the dose rates of 50.0 and 0.2 rad(Si)/s, and then exposed to neutron fluence up to 1 × 1011 n/cm2 (1-MeV equivalent neutron fluence). One sample was first exposed to neutron fluence up to 1 × 1011 n/cm2 (1-MeV equivalent neutron fluence), and then exposed to 60Co γ-rays up to the TID level of 200 krad(Si) at the dose rate of 0.2 rad(Si)/s. The mean dark signal (KD), the dark signal non-uniformity (DSNU), and the noise (VN) versus the total dose and neutron fluence has been investigated. The degradation mechanisms of CMOS APS image sensors have been analyzed, especially for the interaction induced by neutron displacement damage and TID damage

  4. The protector role of Mn2+ in Saccharomyces cerevisiae exposed to 60Co gamma radiation

    International Nuclear Information System (INIS)

    The radiation is present on all over the world and can be classified, according to the effect that produces on matter, as non-ionizing and ionizing. The ionizing radiations transfer a sufficient amount of energy to the molecule and charged atoms called ions can be formatted. The biological organisms have approximately 70% of water and when submit to the incident radiation occur the radiolysis of water. Water radiolysis produces highly reactive oxygen species (ROS) known as free radicals. The ROS can interact with all important biomolecules like lipid, protein and DNA. This interaction can cause the loss of functions of theses molecules and thus lead to cell death. The manganese is a heavy metal that at low concentrations is essential for the biological system, since it is cofactor for action of several enzymes. At high concentrations the manganese is toxic to the organisms. Recently was observed that manganese can have a protector role against oxidative stress. In this work, it was studied the anti-oxidant role of manganese in cells submitted to gamma irradiation. It was performed the determination of two oxidative stress indicators: lipid peroxidation and determination of thiol group, the results presented suggest that the manganese had protective role against lipid damage and in this way, has an antioxidant role. (author)

  5. Effect of 60Co-gamma radiation on the random walk error of interferometric fiber optic gyroscopes

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Two 60Co-gamma radiation experiments were launched to explore the radiation effect on optical components and interferometric fiber optic gyroscope (IFOG). In optical components radiation experiment, the result showed that polarization-maintaining (PM) fiber coil loss was the most affected parameter in all the RWC (random walk coefficient) related parameters, compared with the weak sensitivity of other components parameters. In the IFOG radiation experiment, the RWC performance degradation was found to be almost due to an increase of the PM fiber attenuation. Based on the experiment result, a RWC prediction model in radiation, which is obtained by embedding PM fiber loss expression into the RWC model, was built following a power law of dose and dose rate. An IFOG RWC in space radiation environment was predicted from radiation dose and dose rate by the RWC prediction model. This RWC value calculated from test data is fully accorded to the RWC value predicted from radiation dose.

  6. Proteomics study of progeny of normal human liver cells irradiated by 60Co γ-rays

    International Nuclear Information System (INIS)

    Objective: To characterize the differential protein expression in the progeny of human liver cells surviving from ionizing radiation by the proteomic analysis. Methods: Two-dimensional electrophoresis gel coupled with mass spectrometry was used to explore the specific protein expression in the progeny of 7702 human liver cells surviving from ionizing radiation. Alterations in expression level of protein spots between the control and the progeny groups were statistically analyzed by ImageMaster 2D Platinum software and mass spectrometry was used to identify the protein spots with significantly altered expression-level. Results: The progeny of irradiated ceils were derived from human liver cell line exposed to 0, 2, 4, 6 Gy of 60Co γ-irradiation. A total of 42 differentially expressed proteins between the control and the progeny of the irradiated cells groups were screened, of which 17 were identified by matrix assistant laser desorption ion-top off light-mass spectrometry (MALDI-TOF MS) analysis, including 4 up-regulated and 13 down-regnlated proteins. Conclusions: The differentially expressed proteins profile could be significantly altered in the progeny of irradiated cells. The proteomics approach has the potential to detect the protein changes relevant to radiatian-induced genomic instability (RIGI). Further study of differentially expressed proteins would likely reveal the molecular mechanisms of gene expression in RIGI. (authors)

  7. Effects of accumulated 60Co γ-ray irradiation on the small molecular metabolites in rats urine

    International Nuclear Information System (INIS)

    Objective: To explore the effects of accumulated 60Co γ-ray irradiation on small molecular metabolites in rats urine. Methods: Ten healthy male SD rats were irradiated by 60Co γ-rays in 5 days and the accumulated doses were 0, 0.2, 0.4, 0.6, 0.8, 1.0 Gy, respectively. The metabolites in urine of different groups were measured with 1H-NMR combined with principal components analysis (PCA) and partial least square discriminate analysis (PLS-DA). Results: The metabolites in rat urine were obviously changed after irradiation. Compared with control group, the amount of acetoacetate decreased after irradiation (t=29.7-30.7, P<0.05), but its relative level was stable when the dose increased (P>0.05). Meanwhile,the relative level of hippuric acid increased (t=4.4-21.6, P<0.05) especially when the accumulated dose was higher than 1 Gy (t=21.6, P<0.05). The relative level of proline, taurine and trimethylamine-N-oxide increased after irradiation with the same trend(t=3.5-13.4, 4.7-11.5, 2.9-12.7, P<0.05). Conclusions: The acetoacetate, hippuric acid, proline, taurine, and trimethylamine-N-oxide may be applicable for biomarkers of accumulative irradiation on rat. (authors)

  8. Study on the therapeutic effect of cytokine on acute radiation syndrome induced by 60Co γ ray exposure

    International Nuclear Information System (INIS)

    Objective: To examine the therapeutic effect of combined administration of rhIL-11 and rhG-CSF on acute radiation syndrome induced by 60Coγ ray exposure in beagles. Methods: Sixteen beagles were randomly divided into the control (n=5), symptomatic treatment group (n=5) and cytokine treatment group (n=6). All the beagles in the three groups were exposed to the whole-body irradiation of 60Co γ ray at a dose of 4.5 Gy. The animals in the second group accepted active symptomatic treatment. The animals in the cytokine treatment group were sub-cutaneously administered rhIL -11 and rhG -CSF besides active symptomatic treatment. Hemogram of peripheral blood, pristine apoptosis and necrosis ratio of nucleated cells, the content of IL-2 and IFN-γ in plasma and formation of bone marrow were used to evaluate the therapeutic effect. Results: In the cytokine treatment group, the animal' survival rate 45 days after exposure was increased and hemogram of peripheral blood was improved significantly. The rate of pristine apoptosis and necrosis of nucleated cell declined obviously. Early, the content of both IL-2 and IFN-γ in plasma was up significantly, then the content of IL-2 rapidly descended, but that of IFN-γ was relatively stable. Conclusion: The combined administration of rhIL-11 and rhG-CSF significantly improved the recovery of hematopoietic and immunological function. (authors)

  9. Some Results Of Gamma-60Co Irradiation Application To Breed New Soybean Varieties At Institute Of Agricultural Genetics, 2001 - 2007

    International Nuclear Information System (INIS)

    To overcome the disadvantage characters and continue create new genetical materials in new Soybean variety selection to get high yield, resistance to with disadvantage conditions, good quality. The Institute of Agricultural Genetics successfully combinated the good particularities of mutant varieties DT84/DT83 and received DT2001 variety, and from mutant DT90/DT84 received new variety DT96. These varieties quite resists with rare good drought-tolerant, high yield from 2000 to 3500 kg/ha, appropriate with all of 3 crops: spring, summer and winter and have wide adaptation. DT96, DT2001 varieties were adopted by MARD Scientific Council as New National Varieties. cooperated with Dalat Institute of Nuclear research treated the Gamma - 60Co Irradiation on Soybean and Vegetable Soybean. Irradiated dry seed of 3 varieties DT96, DT2001, DT158 with dose levels of 150, 200, 250 Gy in order to shorten the rise time and strengthen the drought resistance. At M3 generation had selected 3 lines D.96/26, D.01/58, D.58/08, D.58/224, which have rise time from 3 to 5 day shorter and yield higher than control (D.96/150, D.01/245). Irradiated the 2 vegetable Soybean DT02 (to ameliorate its thick shell, improve sweetness and resist with collapse) and DT06 (to ameliorate its heat resistance) with dose levels of 100, 140, 180, 220 Gy were received the generations and now continue being researching the M3 generation in 2007 summer crop. (author)

  10. Resposta de sementes de amendoim a diferentes doses de radiação gama (60Co Response of peanut seeds to different levels of gamma radiation (60Co

    Directory of Open Access Journals (Sweden)

    Tatiana da S. Santos

    2010-10-01

    Full Text Available A radiação gama, proveniente da fonte de 60Co, é bastante utilizada para esterilização, visando a prevenção da decomposição e a toxidez de origem microbiana em diversos produtos. O grau de radiossensibilidade de um embrião vegetal depende da espécie, do estágio de seu desenvolvimento durante a radiação, da dose empregada e do critério usado para medir o efeito biológico, sendo comumente utilizado o teste de germinação. Objetivou-se, com este trabalho, estudar a sensibilidade do amendoim a radiação gama e seus efeitos na germinação, no vigor e na micoflora das sementes da cultivar BRS Havana, irradiadas com uma fonte de 60Co, tipo gammacell, com taxa de dosagem de 12,5 kGy h-1. As doses testadas em kGy foram as seguintes: 0; 0,5; 1,0; 1,5; 2,0; 2,5; 3,0; 6,0; 9,0; 12,0; 15,0; 18,0; 21,0 e 24,0. Com os resultados obtidos, concluiu-se que as doses acima de 3,0 kGy prejudicaram a viabilidade das sementes e as doses acima de 12 kGy comprometeram totalmente o vigor e a germinação das sementes de amendoim. A radiação a partir da dose 2,0 kGy eliminou os fungos Aspergillus flavus e Aspergillus niger e, a partir da dose 3,0 kGy, eliminou o Aspergillus glaucus. O Penicilium spp. permaneceu em mais de 30% das sementes em todos os tratamentos com radiação, não sendo eliminado até a dose de 24 kGy.The gamma radiation from 60Co source is widely used for sterilization aiming at preventing decomposition and toxicity from microbes in several products. The degree of radiosensitvity of a plant embryo depends on the species, the development stage during radiation, doses used and the criteria used to measure the biological effect, the germination test, being commonly used.This work aimed to study the peanut sensitivity to gamma radiation and its effects in the germination, in the vigour and seeds microflora of cultivar BRS Havana, irradiated with 60Co source, type gammacell with rate of dosage of 12.5 kGy h-1. The tested doses were the

  11. Dose-rate effect on chromosomal aberrations induced by 60Co γ-rays irradiation in human peripheral blood lymphocyte

    International Nuclear Information System (INIS)

    To estimate exactly the biological dose of persons exposed to different dose rate, human peripheral blood was exposed to 60Co γ-rays in vitro at low, middle and high dose rates respectively and chromosome samples were prepared, then dose-response curves were established according to the dicentrics and ring frequencies. The result showed that the aberration frequency at same dose level increased with dose rate and there was an obvious dose-rate effect. Absorbed dose estimated with low dose-rate dose-response curve was higher markedly than that with high dose-rate dose-response curve. So, considering the effect of dose-rate, approximate dose-rate dose-response curve should be chosen when absorbed dose estimation and the result will be credible. (authors)

  12. Effects of 60Co γ-ray irradiation on expression of surface antigens in endothelial cells of human umbilical veins

    International Nuclear Information System (INIS)

    Culture of endothelial cells of human umbilical veins and avidin-biotin peroxidase complex (ABC) immunochemical technique were used in the experiment to detect the surface antigens in endothelial cells. Endothelial cells separated from five umbilical cords in original culture were divided into two groups, irradiated and non-irradiated. The cells were irradiated with 15 Gy of 60Co γ-rays at dose rates of 21.78 cGy/min. Then antigens RBC A, HLA-ABC, HLA-DR, CD4 and CD8 were assayed for both groups by the method of ABC. The results showed that the values of integrated optical density (IOD) for the surface antigens in the irradiated cells were lower than those in the non-irradiated cells with the difference in antigen expression in endothelial cells being significant (P<0.05) between the two groups

  13. Biochemical and pharmacological studies of native and irradiated crotamine with gamma radiation of {sup 60}Co; Estudo bioquimico e farmacologico das crotaminas nativa e irradiada com radiacao gama de {sup 60}Co

    Energy Technology Data Exchange (ETDEWEB)

    Mitake, Malvina Boni

    2000-07-01

    Ionizing radiation can change the molecular structure and affect the biological properties of biomolecules. This has been employed to attenuate animal toxins. Crotamine is a strongly basic polypeptide from the South American rattlesnake venom, composed of 42 amino acid residues. It induces skeletal muscle spasms leading to a spastic paralysis of hind limbs in mice. The objective of this thesis was carry out biochemical and pharmacological studies of native and irradiated crotamine with {sup 60} Co. Crotamine was purified from Crotalus durissus terrificus venom by Sephadex G-100 gel filtration followed by ion exchange chromatography, using a Fast Performance Liquid Chromatography (FPLC) system. It was irradiated at 2 mg/ml in 0.15 M Na Cl with 2.0 kGy gamma radiation emitted by a {sup 60} Co source. The native and irradiated crotamine were evaluated by biochemical characterization, toxic activity (LD{sub 50} and biodistribution. The native and irradiated crotamine were labelled with 29.6 MBq of {sup 125} I using chloramine T method, and separated in a Sephadex G-50 column. Male Swiss mice (35{+-} 5 g), were injected i.p. with o.1 mL (2.4 x 10{sup 6} cpm/mouse) of {sup 125} I native crotamine or with 0.4 mL (1.3 x 10{sup 6} cpm/mouse) of {sup 125} I irradiated crotamine. At 0.08; 0.25; 0.5; 1; 2; 4; 8; 12 and 24 hours the animal were killed by ether inhalation. Blood, spleen, liver, kidneys, brain, lungs, heart, and skeletal muscle were collected in order to determine radioactivity content. The results showed that gamma radiation did not change the protein concentration, the electroforetic profile or the primary structure of the protein, although differences were shown by spectroscopic techniques. The gamma radiation diminished the toxicity of crotamine, but it did not abolish bioactivity. Biodistribution studies showed that native and irradiated crotamine have hepatic metabolism and renal elimination. The native and irradiated crotamine have affinity by skeletal

  14. Effect of gamma radiation of 60Co in the variability of chinese bean [Vigna unguiculata (l.) Walpers] en R4M4

    International Nuclear Information System (INIS)

    Selection of plants of Chinese bean coming from seed irradiated with gammas of 60Co in the generation R4M4 (fourth recurrent irradiation, fourth segregate generation) were carried out, taking as selection approaches the plant architecture, the numbers of sheaths for plant, sheath longitude, position of the sheaths, grain size and resistance to plagues and illnesses. 17 lines were selected for grain and 3 lines with fodder characteristics of black grain color were also obtained. (Author)

  15. Structural and optical analysis of 60Co gamma-irradiated thin films of polycrystalline Ga10Se85Sn5

    Science.gov (United States)

    Ahmad, Shabir; Asokan, K.; Shahid Khan, Mohd.; Zulfequar, M.

    2015-12-01

    The present study focuses on the effects of gamma irradiation on structural and optical properties of polycrystalline Ga10Se85Sn5 thin films with a thickness of ∼300 nm deposited by the thermal evaporation technique on cleaned glass substrates. X-ray diffraction patterns of the investigated thin films show that crystallite growth occurs in the orthorhombic phase structure. The surface study carried out by using the scanning electron microscope (SEM) confirms that the grain size increases with gamma irradiation. The optical parameters were estimated from optical transmission spectra data measured from a UV-vis-spectrophotometer in the wavelength range of 200-1100 nm. The refractive index dispersion data of the investigated thin films follow the single oscillator model. The estimated values of static refractive index n0, oscillator strength Ed, zero frequency dielectric constant ε0, optical conductivity σoptical and the dissipation factor increases after irradiation, while the single oscillator energy Eo decreases after irradiation. It was found that the value of the optical band gap of the investigated thin films decreases and the corresponding absorption coefficient increases continuously with an increase in the dose of gamma irradiation. This post irradiation changes in the values of optical band gap and absorption coefficient were interpreted in terms of the bond distribution model.

  16. 60Coγ射线损伤后小鼠造血系统生理指标的动态变化%Changes of Physiological Indexes in Hematopoietic System of Mice after 60Coγ Ray Irradiation

    Institute of Scientific and Technical Information of China (English)

    侯新然; 王晓波; 袭荣刚; 李忠亮; 高慧媛; 吴立军; 马晓梅

    2012-01-01

    Objective To explore the physiological variation of the hematopoietic system in mice after C07 ray irradiation. Methods Body weight, peripheral blood cell counts,the immune organ index and pathological changes in femoral bone marrow of mice were measured at different times after whole-body irradiation with C07 ray. The doses were 2,4,6 Gy respectively. Results The changes of peripheral blood of mice were different. The white blood cell counts declined most rapidly and obviously,followed by the platelet count,with a dose-effect relationship. Three days after radiation, the immune organ index of mice decreased significantly compared with the immune organ index in mice unirradiated. Myeloid elements in bone marrow were reduced and bone marrow hematopoiesis was depressed. Body weight of irradiated mice grew slowly, without significant difference with mice unirradiated. Conclusion 60Coγ ray radiation can decrease peripheral blood cells, decrease the immune organ index and inhibit bone marrow cell proliferation in mice.%目的 探索小鼠60Coγ射线损伤后造血系统各项生理指标的变化规律.方法 采用60Coγ射线对小鼠进行一次性全身照射,剂量分别为2、4、6 Gy,在不同时间分别测定小鼠体质量,外周血细胞计数,免疫器官指数及股骨骨髓的病理变化.结果 照射后小鼠的外周血象有变化,其中白细胞下降最迅速且明显,其次是血小板,且具有剂量效应关系.照射后3d免疫器官指数下降明显,与对照组比较具有显著性差异;骨髓造血细胞数目迅速减少,出现造血抑制;照射后小鼠体质量增加缓慢,但与对照组比较无显著性差异.结论 60Coγ射线照射可引起小鼠外周血细胞下降,免疫器官指数下降,并抑制骨髓造血细胞增生.

  17. The effect of 60Co γ-rays on the contents of paramylon and trehalose in Euglena gracilis

    International Nuclear Information System (INIS)

    Full text: It is reported that the non-reducing disaccharide trehalose is accumulated in various organisms and protects biomolecules against various environmental stresses including heat shock, osmotic shock, and oxidative stresses. Euglena (Euglena gracilis) is photosynthetic unicellular organisms which is classified both as animal and as plant because of its motility. In our previous study, it was shown that salt stress causes degradation of paramylon, the reserve carbohydrate of Euglena, and trehalose, the degraded product of paramylon, accumulated simultaneously to maintain the osmotic pressure of Euglena cells. Euglena is known to be radiation-resistant more than Escherichia coli and other bacteria. Therefore, we have investigated whether or not the same phenomenon could be observed in Euglena after 60Co-gamma irradiation. Exposure of the native Z strain and chloroplast-deficient SM-ZK strain of Euglena to a dose of 500 kGy induced significant paramylon degradation and trehalose accumulation during the incubation in the Koren-Hunter culture medium containing glucose as carbon source after the irradiation. Forty percent of the paramylon was degraded within 10-hr incubation after the irradiation but accumulated trehalose content was about one sixth of that by salt stress. Trehlose accumulation disappeared when the irradiated cells were incubated in phosphate buffer but it recovered when glucose is added to the buffer to the same concentration as K-H media. These results suggest that trehalose accumulation in irradiated Euglena cells plays a role in protecting cellular constituents from oxidative damage caused by gamma-irradiation independently of the response to salt stress

  18. Gamma-ray Astronomy

    CERN Document Server

    Hinton, Jim

    2007-01-01

    The relevance of gamma-ray astronomy to the search for the origin of the galactic and, to a lesser extent, the ultra-high-energy cosmic rays has long been recognised. The current renaissance in the TeV gamma-ray field has resulted in a wealth of new data on galactic and extragalactic particle accelerators, and almost all the new results in this field were presented at the recent International Cosmic Ray Conference (ICRC). Here I summarise the 175 papers submitted on the topic of gamma-ray astronomy to the 30th ICRC in Merida, Mexico in July 2007.

  19. An integrated analysis of the life-shortening effects in mice of fission neutrons and /sup 60/Co γ rays

    International Nuclear Information System (INIS)

    Ten studies on the life-shortening and tumorigenic effects of /sup 60/Co γ rays and fission neutrons from the JANUS reactor have been completed. Young adult B6CF/sub 1/ males and females were exposed to brief single, 24 once-weekly, or 60 once-weekly doses of either radiation and followed for their lifetimes. Two studies involved γ rays delivered in five 22-h days per week for either 23 or 59 elapsed weeks. The mean aftersurvival (MAS) data were analyzed to determine the influence of total dose, sex, exposure pattern, radiation quality, and nonadditive interactions among these factors on dose-response relations between MAS and total dose. Each γ-ray-exposure pattern produces a unique, linear, dose-rate-dependent life-shortening coefficient, which ranges from 0.43 days lost/cGy for single doses to 0.08 days lost/cGy for single doses to 0.08 days lost/cGy for the continuous (59 five-day week) exposures. For total neutron doses below 15 cGy, there is no significant nonlinear (D/sup 2/) term and no apparent dose-rate effect. A significant negative D/sup 2/ term emerges at doses ≥ 20 cGy. Linear coefficients from progressive analyses of data between 1 and 40 cGy are between five and seven days lost/cGy for females and three and four days lost for males. Data between doses of 1 and ≥ 60 cGy are not depicted by a simple dose-response model. RBE/sub m/ lies between 40 and 60 for each sex and could reach 90, if sex differences are ignored

  20. Induction of mutation in Jujube (Zizyphus jujuba Mill) using tissue culture combined with 60Coγ-ray irradiation

    International Nuclear Information System (INIS)

    In vivo and in vitro mutagenesis techniques were assayed to explore effects of irradiation in jujube (Ziziphus jujuba Mill) improvement. 60Co γ-ray irradiated seeds and shoot tips of a land race of jujube originating in Shangdong province of China were micropropagated up to M1V4 generation on MS basal medium containing 2 mg/L BA and 0.4 mg/L IBA. The rooting MS medium contained 1 mg/L BA and 0.6 mg/L IAA, ZEA 1 mg/L, 2, 4-D 0.5 mg/L, and NAA 0.5 mg/L in different combinations. Adventitious buds were also produced from irradiated calli derived from leaf and hypocotyl fragments and the elongated adventitious buds rooted in vitro prior to green house transfer. Different doses (20 to 900Gy) were tested for in vitro explants as well as the jujube kernels irradiation. Six types of leaf shape and seven types of fruit shape mutations were observed and different ripening characters and growth habits were recorded in the orchard on putatively mutated mature trees. Even though there is a need for confirmation and molecular characterization, these mutations may be considered as a new and powerful way for jujube improvement in order to develop genotypes with promising value added traits. (author)

  1. The effects of 60Co γ-ray on poly(ethylene-co-vinyl acetate)/carbon black composites

    Science.gov (United States)

    Lee, Kyoung-Yong; Kim, Ki-Yup

    2008-04-01

    Cables used in a nuclear power plant are irradiation suppressing ones. Until now, researches on the irradiation suppressing cables have mainly been focused on insulation materials. Therefore, in this paper, the non-isothermal crystallization behaviors and degradation characteristics of ethylene vinyl acetate-carbon black (EVA-CB), used as a shielding material, were investigated by means of the Differential scanning calorimetry (DSC) and chemiluminescence analyzer (CL). The specimens were cooled after removing thermal history at 150 °C for 5 min by changing the cooling rates to 5, 7.5, 10, 15 and 20 °C/min with DSC. In addition, after maintaining a thermal equilibrium at each temperature of 25, 50, 75, 100, 125, 150 and 175 °C, their thermoluminescence was measured for 20 min with CL equipment. The 60Co γ-ray was used for irradiation. Tc, T0, T∞ and t1/2 in the DSC experiments are found to decrease gradually as radiation dose increases. Secondly, with the CL experiment, the 0.1, 0.25 and 0.5 MGy EVA-CB composites were found to show a much smaller thermoluminescence than the intact EVA-CB composites, while the 0.75 and 1 MGy EVA-CB composites were found to show a much higher thermoluminescence than ones.

  2. Study about the sensibility in vitro of different strains of Vibrio cholera 01 exposed to 60 Co gamma radiation

    International Nuclear Information System (INIS)

    The presence of some microorganisms in food, or the metabolites originated during their own multiplication may bring several diseases to humans: intoxications and food borne infections. Among the agents that may cause those diseases, we find Vibrio cholerae 01. In this experiment, the studies are focused on the radiosensibility in vitro of four strains of V. cholerae 01, exposed to different doses of ionizing radiation of 60 Co. The results are compared with other data related to bacterial food borne diseases, including water. (author)

  3. In service measurement of a process media distribution by using a sealed gammer-ray source (60Co) at the catalyst riser of the fluid catalytic cracking unit (FCCU) in a petroleum refinery

    International Nuclear Information System (INIS)

    Gamma scans were performed on a catalyst riser of FCCU in service by using a sealed gamma-ray source 60Co and an automatic gamma scanner, specifically designed for a protection against a high heat for the purpose of an investigation the fluidized pattern of a catalyst. The internal media which was composed of the catalyst, the heavy oil, and steam was distributed homogeneously and impurities such as deposited coke were not found at the lower part of the region connected to the nozzles. However, some suspicious zones which were considered as abnormal conditions were detected between the steel grating and the nozzles. Generally the amount of media distribution at the lower part of the riser was larger than that of the upper part. From this experiment by using a gamma source, the conditions of a media distribution were identified and any abnormal areas were successfully localized.

  4. 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.)

  5. INCASOY-35: PRIMERA VARIEDAD DE SOYA OBTENIDA EN CUBA A PARTIR DEL EMPLEO DE TÉCNICAS DE IRRADIACIÓN DE RAYOS GAMMA DE 60Co

    Directory of Open Access Journals (Sweden)

    R. Ortiz

    2005-01-01

    Full Text Available La variedad INCASoy-35 fue obtenida a partir de la irradiación de semillas de la variedad INCASoy-15 con dosis de 240 Gy de rayos gamma 60Co; esta variedad se adapta a siembras de primavera, verano e invierno y puede alcanzar rendimientos de 3 t.ha-1 de granos. Tolera las principales plagas y enfermedades y, en especial, resiste el ataque de nemátodos Meloidogyne incognita. En la época adversa de primavera, las semillas han mostrado tolerancia al deterioro. Tiene capacidad de garantizar altas producciones con bajos insumos, por lo que resulta factible para la agricultura cubana.

  6. Differential expression profiles of microRNAs in liver of 60Co γ-ray irradiated mice

    International Nuclear Information System (INIS)

    Objective: To investigate the differential expression profiles of microRNAs in the liver of 60Co γ-ray irradiated mice using microRNA microarray and to explore their main functions by bioinformatic analysis. Methods: After SPF C57BL/6J mice expose to 4 Gy-single whole body radiation,total number of peripheral WBC and the fMNPCE were measured at 3 d.The differentially expressed miRNAs in mouse liver were detected with miRNA microarray, miRNA-124 and miR-34a were confirmed by real time RT-PCR assay. Bioinformatic analysis was applied to explore target genes and the main functions of the differential expressed miRNAs. Results: Compared with control group, the total number of peripheral WBC decreased (t=2.87, P<0.05), while the fMNPCE in bone marrow increased (t=-2.91, P<0.05) after 4 Gy γ-ray irradiation.miRNA microarray revealed that 17 miRNAs were differentially expressed, in which 9 up-regulated, 8 down-regulated. The expression levels of miR-124 and miR-34a were coincident with the result of real time RT-PCR. GO analysis showed that some pathways including adherens junction and cell cycle were suppressed, while some immune-related pathways were activated. Conclusions: miR-34a and miR-194 were involved in the regulation of acute radiation damage, some other miRNAs including miR-124, miR-382 and miR-92a* also played important roles in radiation process. (authors)

  7. Mutation effect of radiation of 60 Co γ ray on variant strain of Pleurotus ostreatus%60Coγ射线对侧耳属变异株的诱变效应

    Institute of Scientific and Technical Information of China (English)

    陈再鸣; 曹若彬; 黄玲; 董荷玲

    2001-01-01

    应用60Co γ射线对侧耳属变异株的双核菌丝体进行辐射诱变处理,并对其再生菌落进行菌丝形态学、细胞学、生理生化鉴定。结果发现,诱变株菌落形态发生明显变化,气生菌丝减少,生长过程减慢,细胞直径变大,分枝增多,与出发菌株拮抗线明显,EST,POD同工酶显示其酶谱差异显著。结实性研究表明,诱变株较出发株子实体分化正常,产量提高,抗性增强,品质良好。显示60 Co γ射线辐射诱变是改良侧耳属菌株的有效途径。%The dicaryotic hyphae of the variant strain of P.ostreatus was treated by radiation of 60 Co γ ray. Mycelial morpholagical,cytological and physiological-biochemical characteristics of its mutant strain were studied.The results showed that the mutant strain had less aerial mycelium.Lower colony growth rate,bigger mycelium diameter,more branch on vegetative growth phase and had more fruitbody formation,higher yield,better quality on reproductive growth phase than the initial strain.Clear ant-agnistic line and significant differences of isoenzyme pattern of EST and POD existed between the mutant and initial strains.It showed that induced mutation from dicaryotic hyphae by 60 Co γ ray was an effective means of gaining excellent rejuvenation strain of P.ostreatus.

  8. Comparison of the standards of air kerma of the OMH and the BIPM for 60Co gamma radiation

    International Nuclear Information System (INIS)

    A direct comparison between the standards for air kerma of the Orszagos Meresugyi Hivatal (OMH) and of the Bureau International des Poids et Mesures (BIPM) has been carried out in the 60Co radiation beams of the BIPM. The result, expressed as a ratio of the OMH and the BIPM standards for air kerma, indicates a relative difference of 10.9 x 10-3 with a combined standard uncertainty of 2.2 x 10-3. This new result agrees at the level of 0.4 x 10-3 with the earlier direct comparisons performed in 1986 and 1994, as modified in 2001 by the application of wall and axial non-uniformity correction factors, calculated for the OMH standards using the Monte Carlo method. (authors)

  9. Supplementary comparison CCRI(I)-S2 of standards for absorbed dose to water in 60Co gamma radiation at radiation processing dose levels

    DEFF Research Database (Denmark)

    Burns, D. T.; Allisy-Roberts, P. J.; Desrosiers, M. F.;

    2011-01-01

    Eight national standards for absorbed dose to water in 60Co gamma radiation at the dose levels used in radiation processing have been compared over the range from 1 kGy to 30 kGy using the alanine dosimeters of the NIST and the NPL as the transfer dosimeters. The comparison was organized by the B......Eight national standards for absorbed dose to water in 60Co gamma radiation at the dose levels used in radiation processing have been compared over the range from 1 kGy to 30 kGy using the alanine dosimeters of the NIST and the NPL as the transfer dosimeters. The comparison was organized...... by the Bureau International des Poids et Mesures, who also participated at the lowest dose level using their radiotherapy-level standard for the same quantity. The national standards are in general agreement within the standard uncertainties, which are in the range from 1 to 2 parts in 102. Evidence of a dose...

  10. Effect of gamma radiation of {sup 60}Co in the variability of chinese bean [Vigna unguiculata (l.) Walpers] en R{sub 4}M{sub 4}; Efecto de la radiacion gamma de {sup 60}Co en la variabilidad de frijol chino [Vigna unguiculata (l.) Walpers] en R{sub 4}M{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Salmeron E, J.; Bueno J, J.E.; Valencia E, F. [CSAEGro, Iguala, Guerrero, Tel and Fax 01 733 (33) 24328 (Mexico); Cervantes S, T. [IREGEP (Mexico); Cruz T, E. De la [ININ, Departamento de Biologia, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: csaegro@prodigy.net.mx

    2007-07-01

    Selection of plants of Chinese bean coming from seed irradiated with gammas of {sup 60}Co in the generation R{sub 4}M{sub 4} (fourth recurrent irradiation, fourth segregate generation) were carried out, taking as selection approaches the plant architecture, the numbers of sheaths for plant, sheath longitude, position of the sheaths, grain size and resistance to plagues and illnesses. 17 lines were selected for grain and 3 lines with fodder characteristics of black grain color were also obtained. (Author)

  11. 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.

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

    Science.gov (United States)

    Lambertin, D.; Boher, C.; Dannoux-Papin, A.; Galliez, K.; Rooses, A.; Frizon, F.

    2013-11-01

    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 60Co sources up to 1000 kGy. Various Na-geopolymer with three H2O/Na2O 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.

  13. Comparison of the standards of absorbed dose to water of the OMH and the BIPM for 60Co γ rays

    International Nuclear Information System (INIS)

    A comparison of the standards of absorbed dose to water of the Orszagos Meresugyi Hivatal (OMH), Budapest, Hungary and of the Bureau International des Poids et Mesures (BIPM) has been made in 60Co radiation. The results show that the OMH and the BIPM standards for absorbed dose to water are in close agreement, the difference being within the estimated uncertainty. (authors)

  14. Soil compaction and gamma radiation ({sup 60}Co) in the development of the cowpea beans [Vigna unguiculata, (L) Walp]; Compactacao do solo e radiacao gama ({sup 60}Co) no desenvolvimento do feijao caupi [Vigna unguiculata, (L) Walp

    Energy Technology Data Exchange (ETDEWEB)

    Viana, Eliane Ferreira; Colaco, Waldeciro [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Radioagronomia]. E-mails: aroucha@ufpe.br; wcolaco@ufpe.br

    2005-08-15

    The objective is to investigate the effect of compaction and increased doses of gamma radiation on the development of cowpea [Vigna unguiculata, (L) Walp] var. IPA-206 cultivated in a Neossolo fluvic soil, artificially compacted. Significant differences were observed in plant height, with the increase doses in soil density (1.30 Mg.m{sup -3} - compacted soil and 1.70 Mg.m{sup -3} - non-compacted soil), and in response to increased doses of irradiation (y-rays) [ [0, 100, 200 and 300 Gy). The diameter of the stem was significantly reduced in response to the increase in soil density, however the same did not occur in relation to the doses of irradiation (y-rays) holding capacity of the soil was reduced in response to the increase in soil density. (author)

  15. Expression changes of human mitochondrial COX genes in human lymphocytes after exposed by 60Co γ-rays

    International Nuclear Information System (INIS)

    Objective: To explore the changes of human mitochondrial COX Ⅰ , COX Ⅱ and COX Ⅲ genes expression induced by ionizing irradiation. Methods: Changes of human COX genes expression were detected by RT-PCR and Real-time PCR 8 h after the irradiation in human lymphoblastoid cell lines,which were exposed to 1-10 Gy 60Co γ-rays. The protein levels were detected by flow cytometry and the COX activity was measured by colorimetry. The dose-effect relationships between the expression changes of the genes and the doses were established. The changes of these genes expression were also analyzed at different post-radiation time-points between 0.5 h and 72 h after irradiation of 5 Gy in order to explore the time-effect. Results: The expression of 3 genes at mRNA level was up-regulated. A good dose-effect relationship was showed for COXⅠ and COX Ⅲ at dose range of 0-3 Gy and 0-8 Gy for COX Ⅱ (FCOXⅠ=116. 62, FCOXⅡ=17. 89, FCOXⅢ = 8.20, P<0.05). For the time-effect after irradiation, the gene expression levels of COX Ⅱ and COX Ⅲ genes were up-regulated and the peak change occurred at 4 h after irradiation. For COX Ⅰ gene, the mRNA expression levels were down-regulated during 0.5-72 h (FCOXⅠ=31.99, FCOXⅡ=19.47, FCOXⅢ=20.64, P<0.05 ). At the protein level, the levels of COX Ⅰ and COX Ⅱ were lowered in lower doses and enhanced in higher doses, and the levels of COX Ⅲ were decreased at all dose levels (FCOXⅠ=16.96, FCOXⅡ=32.5, FCOXⅢ=6.51, P<0.05). The protein levels of COX Ⅰ and COX Ⅱ were enhanced during 4-72 h and 8-72 h respectively after 5 Gy irradiation (FCOXⅠ=14.68,FCOXⅡ=17.18, FCOXⅢ =2.52, P<0.05). The activities of COX were lowered at different dose levels and different time-points. Conclusions: Ionizing radiation might induce the changes in mitochondrial COX Ⅰ, COX Ⅱ and COX Ⅲ gene expression, and lead to the reduction of the COX activities. (authors)

  16. Study of the action of 60Co gamma radiation on Salmonella poona, Escherichia coli and Alicyclobacillus acidoterrestris in mango pulp

    International Nuclear Information System (INIS)

    The application of non-thermal treatments has proven effective in inhibiting bacteria such as Salmonella and Escherichia coli. Mango is a fruit of national consumption with a great exportation potential. Meanwhile, outbreaks of food borne disease related to mango consumption caused mistrust on the degree of food security offered by the product. The objective of this work was to establish the radioresistance of bacteria Escherichia coli, Salmonella Poona and Alicyclobacillus acidoterrestris on the mango pulp by the calculation of the D10 values and to know the radiation effect on the sensory characteristics of the fruit pulp. The microbiological profile of frozen mango pulp available at the local market was also established using conventional methods of plating and Most Probable Number (MPN). The pulps experimentally inoculated with the bacteria listed above were irradiated with doses of 0, 1, 2, 3, 4 and 5kGy in a 60Co source. The sensory analysis was performed using a dose of 5 kGy, using the triangular test and the test of acceptance with hedonic scale. The results of this study show that the quality of mango pulp sell in the local market is not satisfactory in accordance with the standards established by the Brazilian law and the literature, showing the need of using other tools to achieve acceptable levels of quality. The D10 values obtained are in the range of 1.01 and 1.09kGy for E. coli ATCC 8739, 0.60 and 0.98kGy for S. poona and 0.72 e 0.88kGy for A. acidoterrestris respectively. The triangular test showed that a 5kGy radiation dose changed the sensory characteristics of mango pulp. Nevertheless, sensory analysis of a food product prepared with the irradiated pulp obtained good acceptance in the attributes of global appearance, flavor and aroma. (author)

  17. Study of the action of 60Co gamma radiation on Salmonella poona, Escherichia coli and Alicyclobacillus acidoterrestris in mango pulp

    International Nuclear Information System (INIS)

    The application of non-thermal treatments has proven effective in inhibiting bacteria such as Salmonella and Escherichia coli. Mango is a fruit of national consumption with a great exportation potential. Meanwhile, outbreaks of foodborne disease related to mango consumption caused mistrust on the degree of food security offered by the product. The objective of this work was to establish the radioresistance of bacteria Escherichia coli, Salmonella Poona and Alicyclobacillus acidoterrestris on the mango pulp by the calculation of the D10 values and to know the radiation effect on the sensory characteristics of the fruit pulp. The microbiological profile of frozen mango pulp available at the local market was also established using conventional methods of plating and Most Probable Number (MPN). The pulps experimentally inoculated with the bacteria listed above were irradiated with doses of 0, 1, 2, 3, 4 and 5 kGy in a 60Co source. The sensory analysis was performed using a dose of 5 kGy, using the triangular test and the test of acceptance with hedonic scale. The results of this study show that the quality of mango pulp sell in the local market is not satisfactory in accordance with the standards established by the Brazilian law and the literature, showing the need of using other tools to achieve acceptable levels of quality. The D10 values obtained are in the range of 1.01 and 1.09 kGy for E. coli ATCC 8739, 0.60 and 0.98 kGy for S. poona and 0.72 and 0.88 kGy for A. acidoterrestris respectively. The triangular test showed that a 5 kGy radiation dose changed the sensory characteristics of mango pulp. Nevertheless, sensory analysis of a food product prepared with the irradiated pulp obtained good acceptance in the attributes of global appearance, flavor and aroma. (author)

  18. 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.

  19. The effects of 60Co γ-ray irradiation on the DC characteristics of enhancement-mode AlGaN/GaN high-electron-mobility transistors

    Institute of Scientific and Technical Information of China (English)

    Chen Chao; Tian Ben-Lang; Liu Xing-Zhao; Dai Li-Ping; Deng Xin-Wu; Chen Yuan-Fu

    2012-01-01

    The effects of 60Co y-ray irradiation on the DC characteristics of AlGaN/GaN enhancement-mode high-electronmobility transistors (E-mode HEMTs) are investigated.The results show that having been irradiated by 60Coγ-rays at a dose of 3 Mrad (Si),the E-mode HEMT reduces its saturation drain current and maximal transconductance by 6% and 5%,respectively,and significantly increases both forward and reverse gate currents,while its threshold voltage is affected only slightly.The obvious performance degradation of E-mode AlGaN/GaN HEMTs is consistent with the creation of electronegative surface state charges in the source-gate spacer and gate-drain spacer after being irradiated.

  20. Gamma ray camera

    Science.gov (United States)

    Perez-Mendez, Victor

    1997-01-01

    A gamma ray camera for detecting rays emanating from a radiation source such as an isotope. The gamma ray camera includes a sensor array formed of a visible light crystal for converting incident gamma rays to a plurality of corresponding visible light photons, and a photosensor array responsive to the visible light photons in order to form an electronic image of the radiation therefrom. The photosensor array is adapted to record an integrated amount of charge proportional to the incident gamma rays closest to it, and includes a transparent metallic layer, photodiode consisting of a p-i-n structure formed on one side of the transparent metallic layer, and comprising an upper p-type layer, an intermediate layer and a lower n-type layer. In the preferred mode, the scintillator crystal is composed essentially of a cesium iodide (CsI) crystal preferably doped with a predetermined amount impurity, and the p-type upper intermediate layers and said n-type layer are essentially composed of hydrogenated amorphous silicon (a-Si:H). The gamma ray camera further includes a collimator interposed between the radiation source and the sensor array, and a readout circuit formed on one side of the photosensor array.

  1. SVOM Gamma Ray Monitor

    CERN Document Server

    Dong, Yongwei; Li, Yanguo; Zhang, Yongjie; Zhang, Shuangnan

    2009-01-01

    The Space-based multi-band astronomical Variable Object Monitor (SVOM) mission is dedicated to the detection, localization and broad-band study of Gamma-Ray Bursts (GRBs) and other high-energy transient phenomena. The Gamma Ray Monitor (GRM) onboard is designed to observe the GRBs up to 5 MeV. With this instrument one of the key GRB parameter, Epeak, can be easily measured in the hard x-ray band. It can achieve a detection rate of 100 GRBs per year which ensures the scientific output of SVOM.

  2. SVOM gamma ray monitor

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The space-based multi-band astronomical Variable Object Monitor(SVOM) mission is dedicated to the detection,localization and broad-band study of gamma-ray bursts(GRBs) and other high-energy transient phenomena.The gamma ray monitor(GRM) onboard is designed to observe GRBs up to 5 MeV.With this instrument,one of the key GRB parameters,Epeak,can be easily measured in the hard X-ray band.It can achieve a detection rate of 100 GRBs per year which ensures the scientific output of SVOM.

  3. Effects of Nitric Oxide on Growth and Sensitivity of Human Glioma A172 Cells to 60Co and X-ray Radiation

    Institute of Scientific and Technical Information of China (English)

    QiuRong; LiuBing; GuoChuanling; LiWenjian; MaQiufeng; LiSha

    2003-01-01

    Nitric oxide (NO)has been implicated both in regression and progression of tumors due to its production by both tumor cells and infiltrating lymphocytes. Ionizing radiation causes the regression of tumors, and can augment the production of NO by macrophages in vitro. The authors examined the effect of nitric oxide (NO) generating agent sodium nitroprusside (SNP) on the growth and radiosensitivity of cultured glioma A172 cells to 60Co or X-ray radiation.

  4. The response to climate factors for the different specificity in M2 physiology of 60Co γ-ray irradiated flowers

    International Nuclear Information System (INIS)

    Physiology and climate factor of different M2 flower (Begonia tuberhybrida Voss and Dahlia pinnata Cav root) after 60Co γ-ray irradiated were determined. The result showed that transpiration rate, stoma conductance, intercellular CO2 concentration of M2 of Dahlia pinnata Cav are affected obviously with climate factors, however, effect on the photosynthetic speed was not found, and M2 of Begonia tuberhybrida Voss was not significant for physiology to climate

  5. 60Co-γ辐射对菊苣种子发芽及幼苗生理的影响%Effects of 60Co-γ-rays Irradiation on Chicory Seed Germination and Seedling Physiology

    Institute of Scientific and Technical Information of China (English)

    张玉; 白史且; 李达旭; 王曾珍

    2013-01-01

    Chicory seeds were irradiated with 60Co-γ-rays at 100, 150, 200 and 300 Gy to determine germination rate and physiological characteristics from mutagenic effects of irradiation doses. Results showed that seed germination rate decreased as the irradiation dosage increased. There was significant difference between 200 Gy irradiation dosage and control(P<0. 05). Superoxide dismutase (SOD) activities, peroxi-dase (POD) activities, soluble protein and soluble sugar contents first increased then declined with a gradual irradiation increase, and differed significantly between control and 150 Gy, 100 Gy, 150 Gy, 150 Gy treatments (P<0. 05), respectively. MDA content increased with increased irradiation dosage, and there was significant difference between control and the treatments above 150 Gy dose (P<0. 05). The protein content first increased then declined, and differed significantly between control and treatments (P<0. 05). It was concluded that the mutagenic effect of chicory irradiated by low dosage (below 150 Gy) was not obvious. However, physiological and biochemical characteristics of chicory irradiated above 200 Gy were significantly altered. The study provides a theoretical basis for chicory radiation mutation breeding.%为明确60 Co-γ射线对菊苣(Cichorium intybus L.)辐照诱变效果,采用不同剂量60Co-γ射线(100 Gy,150 Gy,200 Gy和300 Gy)辐照处理菊苣种子,测定其发芽率和相关生理指标.结果表明:随着辐照剂量的增加,菊苣发芽率降低,200 Gy以上辐照处理发芽率与对照差异显著(P<0.05);超氧化物歧化酶(SOD)、过氧化物酶(POD)活性、可溶性蛋白和可溶性糖含量随着辐照剂量增加均表现为先升后降的趋势,分别在辐射剂量为150 Gy,100 Gy,150Gy,150 Gy及以上时与对照差异显著(P<0.05);丙二醛(MDA)含量随着辐照剂量增加而逐渐升高,150 Gy以上辐照处理与对照差异显著(P<0.05);蛋白含量呈现先增后减的趋

  6. A biological effectiveness study on chromosomal aberrations induced by fission neutrons versus 60Co γ-rays in human peripheral blood lymphocytes

    International Nuclear Information System (INIS)

    Objective: Whole blood lymphocytes samples being exposed to neutrons of 18 MeV energy and 60Co γ-rays respectively, both good dose-response relationships and relative biological effectiveness (RBE) were derived. Methods: Heparinized whole blood samples were exposed to neutrons and 60Co γ-rays, respectively. Radiation doses were from 0.5 Gy to 3.0 Gy. Dose rate was 0.2 Gy/min. Unstable chromosomal aberrations dicentrics and centric rings (dic+r), the same as Micronuclei in binucleated cells, were scored. Relative biological effectiveness (RBE) values of dic+rand Micronucleus were derived. Results: Chromosomal aberrations (dic+r) and Micronucleus induced by either neutrons or 60Co γ-rays had a good dose-response relationship. RBE value of chromosomal aberrations, exposed neutrons at 0.5-3.0 Gy, ranged from 1.59 to 2.81, similarly, micronucleus from 1.23 to 2.14. Conclusion: linear-quadratic dose-response was found for the induction of dic+r and Micronucleus in human lymphocytes exposed in vitro to neutrons of 18 MeV energy. neutrons has higher biological effectiveness in low doses. (authors)

  7. Measurement of 60CO gamma radiation induced attenuation in multimode step-index POF at 530 nm

    Directory of Open Access Journals (Sweden)

    Kovačević Milan S.

    2013-01-01

    Full Text Available As optical fibres are used ever more extensively in space applications, nuclear industry, medicine and high-energy physics experiments, it has become essential to investigate the influence of ionizing radiation on their characteristics. In this work, the radiation-induced attenuation at 530 nm is investigated experimentally in step-index multimode polymethyl-methacrylate plastic optical fibres exposed to low dose-rate gamma radiation. Cumulative doses ranged from 50 Gy to 500 Gy. The radiation induced attenuation has been empirically found to obey the power law RIA= aDb, where D is the total radiation dose and a and b are the constants determined by fitting.

  8. 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.

  9. 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.

  10. Gamma-Ray Bursts

    Science.gov (United States)

    Gehrels, Neil; Mészáros, Péter

    2012-08-01

    Gamma-ray bursts (GRBs) are bright flashes of gamma rays coming from the cosmos. They occur roughly once per day, typically last for tens 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 afterglow.

  11. Gamma Ray Bursts

    CERN Document Server

    Gehrels, Neil; 10.1126/science.1216793

    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 10s 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.

  12. A new cane variety-Guitang No.22 bred by 60Co γ-ray induced mutation

    International Nuclear Information System (INIS)

    Guitang No.22 was developed through seed stems of Xintaitang No.1 exposed at a dosage of 80 Gy 60Co γ-radiation. In Guangxi regional variety test, the results show that the cane yield and the sugar yield are about 106.95 and 14.21 t/hm2 respectively. Moreover, the highest tonnage of biomass and fermentable carbohydrates reaches about 188.1 and 48.92 t/hm2, respectively. Guitang 22 is a new variety which has the characteristic of both sugar cane and energy cane. (authors)

  13. Description of morphologic characters in avocado trees (Persea americana. Mill) var. Hass, submitted to gamma radiation of 60 Co

    International Nuclear Information System (INIS)

    It was carried out the characterization of 77 trees of avocado ''Hass'' subjected to gamma radiation of Co60, in doses of 0, 5, 10,15, 20 and 25 Gy based on previous studies of radiosensitivity with ends of improvement located in the experimental center ''La Labor'' belonging to the foundation Salvador Sanchez Colin. CICTAMEX. S C. in Temascaltepec, Mexico. It was carried out the morphological characterization of this variety according to the nomenclature settled down by the International Office of Genetic Resources (IBPGRI), registering 27 variables for the description of the tree, 33 for description of the fruit and 14 for the characterization of the seed. Regarding the architectural characterization 10 variables were evaluated. Using gamma radiation of Co60 in the doses of 15 and 20 Gy it was detected a reduction of 22% in the portage of the tree, likewise had reduction the diameter of the trunk and of the foliage. It was found that the reduction in the behavior of the tree induces to a bigger variation of the form of the same one, in the distribution of the branches in the form of the fruit and in the form of the seed you Also detects a remarkable increment in the productivity of some hoist irradiated regarding the architecture of the tree one observes that the angle of inclination of the branches increase when being increased the radiation dose and that the longitude of the annual section of growth decreased significantly in the doses of 20 and 25 Gy. One observes a significant Increment in the I number of buds prolepticos in those hoist irradiated in the I finish mbdulo of rhythmic growth. Io that indicates a change substantial in the I inhabit of growth With the purpose of determining if the changes in morphology and architecture of the tree corresponded with the modification at level meristematico, they were carried out observations to the court microscope of having knitted apical vegetative meristematico in samples of you hoist of all the treatments

  14. Study about the sensibility in vitro of different strains of Vibrio cholera 01 exposed to 60 Co gamma radiation; Estudo da sensibilidade in vitro de diferentes cepas de Vibio cholerae 01 a radiacao gama de 60Co

    Energy Technology Data Exchange (ETDEWEB)

    Moraes, Ivany Rodrigues de [Instituto Adolfo Lutz, Sao Paulo, SP (Brazil). Servicos de Saude; Gelli, Dilma Scala; Jakabi, Miyoko [Instituto Adolfo Lutz, Sao Paulo, SP (Brazil). Secao de Microbiologia; Mastro, Nelida Lucia del [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: nlmastro@net.ipen.br

    1998-07-01

    The presence of some microorganisms in food, or the metabolites originated during their own multiplication may bring several diseases to humans: intoxications and food borne infections. Among the agents that may cause those diseases, we find Vibrio cholerae 01. In this experiment, the studies are focused on the radiosensibility in vitro of four strains of V. cholerae 01, exposed to different doses of ionizing radiation of {sup 60} Co. The results are compared with other data related to bacterial food borne diseases, including water. (author)

  15. Toxoplasma gondii gamma irradiation using Co-60; Irradiacao do Toxoplasma gondii com gama do {sup 60} Co

    Energy Technology Data Exchange (ETDEWEB)

    Serra-Freire, Nicolau Maues [Universidade Federal Rural do Rio de Janeiro, RJ (Brazil). Dept. de Parasitologia Animal; Maliska, Carmelindo [Hospital Central do Exercito, Rio de Janeiro, RJ (Brazil). Servico de Medicina Nuclear; Norberg, Antonio Neres [Instituto de Biologia do Exercito (IBEx), Rio de Janeiro, RJ (Brazil)

    1996-07-01

    The use of nuclear power through radiation for the destruction of microorganisms which cause food deterioration, infections and toxicosis, is specifically for peaceful purposes. Toxoplasma gondii is a protozoa responsible for illnesses in humans and animals. One of the most common ways of transmission is through raw or poorly cooked meat. There is little information on the resistance of T. gondii to radiation. The objective of this research is to determine the Minimum Lethal Dose (MLD) of gamma radiation for those microorganisms. Suspensions of T. gondii containing approximately one million taquizoites/ml were irradiated with doses between up 0,01 up to 0,15 kGy (Kilogray) and inoculated to mice. The surviving T. gondii were re-irradiated with 0,01 up to 0,16 kGy. The irradiated protozoa were totally destroyed with a 0,15 kGy dose (MLD). Taquizoites issued from live protozoa of 0,14 kGy also were completely destroyed with dose of 0,15 kGy. No increase in resistance was observed regarding the non irradiated protozoa. (author)

  16. Effects of 60Co gamma radiation on toxicity and hemorrhagic, myonecrotic, and edema-forming activities of Cerastes cerastes venom

    International Nuclear Information System (INIS)

    Antisera are used as effective antidotes against the local effects of snake bites. To improve antisera production and extend the life of surrogates used to produce antibodies, the chronic effects of venom toxicity must be reduced. The present study evaluated the effectiveness of gamma irradiation to reduce the local effects associated with viperid snake bites by evaluating in NMRI mice the toxicity and edematic, hemorrhagic, and myonecrotic activities of native and irradiated Cerastes cerastes venoms. These results indicated that the toxicity of irradiated venoms (1 and 2 kGy) decreased as compared with that of native venom. The edematic and hemorrhagic activities were also reduced in the detoxified samples, particularly with the 2-kGy radiation dose. Furthermore, the creatine phosphokinase (CPK) activity was significantly increased in the serum and decreased in the myocardium after envenomation with native venom, but no significant enzymatic changes were observed in mice envenomated with irradiated venom. Histopathologic evaluation showed that native venom caused severe degenerative changes in the myocardium. In the case of 2-kGy-irradiated venom, no tissue alterations were observed. These results indicate that irradiation of venom with a 2-kGy dose may offer an effective method for reducing the chronic toxic effects of venom in immunized animals. (author)

  17. Screening Quality Mutants of Wheat Radiated by 60CoRay and Molecular Identification%60Co-γ射线诱变小麦品质突变体的筛选及分子标记检测

    Institute of Scientific and Technical Information of China (English)

    来德娥; 赵平; 王敏; 张从宇

    2012-01-01

    为了探索小麦品质性状的物理诱变效应,用300Gy的60Co-γ射线辐射小麦品种河科2号的干种子,对M3代234个株系的蛋白质含量、湿面筋含量、沉降值、硬度和产量性状进行变异分析和SSR分子鉴定,以超过均值±2×标准差确定变异株系.结果表明,在M3代群体中,蛋白质含量有13个株系发生正向变异,5个株系发生负向变异;湿面筋含量有8个株系发生正向变异,3个株系发生负向变异;沉降值有6个株系发生正向变异,3个株系发生负向变异;硬度有2个株系发生正向变异,9个株系发生负向变异;产量有5个株系发生正向变异,4个株系发生负向变异.相关分析表明,M3群体蛋白质含量、湿面筋含量、沉降值呈极显著正相关,表现出平行变异的趋势.初步筛选出蛋白质含量和湿面筋含量符合国家强筋小麦标准(蛋白质含量≥15%,湿面筋含量≥35%)的株系8个.经SSR分子标记检测,与控制小麦蛋白质含量的基因存在连锁的2个特异引物Xbarc164和Xgwm161在以上8个变异株系都呈现多态性标记,表明这些株系与蛋白质含量相关的基因可能发生了变异.%To clarify the mutagenic effects of radiation to quality characters of wheat, dry seeds of wheat variety Heke 2 were radiated by 60Coray with the dose of 300 Gy. The genetic variation of 234 M3 lines on protein content,wet gluten content,sedimentation value,hardness and yield were analyzed,and the mutants were identified by molecular marker. Depending on the criterion of over mean ±2 s, 13 positive mutant lines and 5 negative mutant lines in protein content,8 positive mutant lines and 3 negative mutant lines in wet gluten content, 6 positive mutant lines and 3 negative mutant lines in sedimentation value,2 positive mutant lines and 9 negative mutant lines in hardness,and 5 positive mutant lines and 4 negative mutant lines in yield were identified from 234 M3 lines, respectively. Significant

  18. Study of recombination processes for 'electron-hole' pairs in germanium irradiated by {gamma} rays from {sup 60}Co using the photovoltaic effect in P-N junctions; Etude du processus de recombinaison des paires ''electron-trou'' dans le germanium irradie par les rayons {gamma} du cobalt 60 a l'aide de l'effet photovoltaique dans les jonctions P-N

    Energy Technology Data Exchange (ETDEWEB)

    Zahedi-Mochadam, A.A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-10-01

    Using the photo-voltaic effect in p-n junctions, we have studied, during bombardment, the mechanism of the recombination of 'electron-hole' pairs in the presence of structure defects produced in germanium of the N and P types by {gamma} rays from a Co{sup 60} source. At 310 K the level of the recombination centres is situated 0.25 eV above the conduction band and the capture cross-sections of the holes and of the electrons have the respective values of: {sigma}{sub p} = 4 X 10{sup -15} cm{sup 2} and {sigma}{sub n} = 3 X 10{sup -15} cm{sup 2}. The value of {sigma}{sub n} appears to be under-estimated because the number of defects in P-type samples appears to be lower than that in N-type samples. These results lead to the conclusion that the interstitials are responsible for the recombination. At 80 K it has been found that in N-type samples, a shallow level exists at O.05 eV below the conduction band with a capture cross-section for the holes of {sigma}{sub p} {>=} 10{sup -14} cm{sup 2}. We believe that in this case the recombination of charge carriers is controlled by the neighbouring 'defect-interstitial' pairs. In P-type samples at low temperature, the life-time is practically constant during irradiation. This fact is attributed to a spontaneous annealing of defects ol purely electrical origin. In the last part of the work the study of the photo-voltaic effect applied to the problem of gamma radiation dosimetry is considered. It is shown that such dosimeters, based on this principle, make it possible to measure the intensity of gamma rays over a very wide range. (author) [French] En utilisant l'effet photovoltaique dans les jonctions p-n, nous avons etudie au cours du bombardement le mecanisme de recombinaison des paires 'electron-trou' en presence des defauts de structure introduits dans le germanium de type N et de type P par les rayons gamma d'une source de Co{sup 60}. A 310 K, le niveau des centres de recombinaison se

  19. 60Coγ射线辐照不同麻种种子的细胞学效应%Cytological Effects on Seeds of Hibiscus cannabinus and Cannabis sativa Irradiated by 60Coγ ray

    Institute of Scientific and Technical Information of China (English)

    周立人; 吴雪琴; 魏晓飞; 李布青

    2003-01-01

    通过5种不同剂量的60Coγ射线对两个不同麻种3个品种材料的种子辐照效应研究表明,低剂量的60Coγ射线辐照能促进麻类作物根尖细胞的有丝分裂.但随着γ射线辐照剂量的增加,根尖细胞有丝分裂指数呈不同程度的下降趋势.60Coγ射线辐照能诱发根尖细胞的染色体畸变和核畸变,出现桥、断片、落后染色体、微核、双核、小核等多种畸变类型,并且辐照剂量越大,根尖细胞畸变类型越多,变异频率越高.研究结果还表明不同麻种、同一麻种不同品种对60Coγ射线的辐射敏感性不同,红麻中杂红305最强,红麻福红2号次之,大麻最弱.

  20. 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

  1. Effect of low dose irradiation of 60Co γ-rays on seed germination, seedling growth and enzymes activity of Lactuca sativa

    International Nuclear Information System (INIS)

    The seeds of Lactuca sativa were irradiated by different doses (10, 20, 30, 40, 50 Gy) of 60Co γ-rays. The effects of low dose irradiation on seed germination, seedling growth and enzymes activity were investigated. The results indicated that low dose irradiation could promote germination rate, germinating viability, germination rate in the field, root length and height of seedling. The suitable dosage for low dose irradiation for Lactuca sativa was 30 Gy. POD activity after irradiation treatment in the range of 10 to 50 Gy and CAT activity after irradiation treatment in the range of 20 Gy to 40 Gy was lower than that of control. (authors)

  2. The effects of seeds irradiation with 60Co γ-ray on seed germination and shoot growth of Brassica campetris L. ssp. Chinensis var. utilis

    International Nuclear Information System (INIS)

    Seeds of Brassica campetris L. ssp. Chinensis var. utilis pre-soaked with water for 1h were irradiated with 60Co γ-ray. Irradiation delayed the germination of seeds but did not affect the germination rate. The height, root length, fresh weight and survival rate of seedlings decreased with the increasing of irradiation dose. There were significant negative correlation between death rate and the height, root length and fresh weight. The dose of 200 - 300 Gy were recommended as suitable irradiation doses for pre-soaked seeds

  3. A comparison of pdd for 60Co teletherapy units

    International Nuclear Information System (INIS)

    Although BJR supplement No 17 provides TAR and PDD tables for 60Co gamma rays, due to inherent differences hat exists among individual teletherapy machine and their source it is essential to measure TAR and PDD that are applicable for user's teletherapy unit. TAR and PDD values for different field sizes at 80 cm SSD, open field, gantry angle 0o, collimator angle 0o were determined in CIRUS 60Co teletherapy unit by ionization chamber NE2570/1B Farmer type. PDD for a standard field size 10 10 cm2, open field, gantry angle 0o,Collimate angle 0o were determined in MEDNIF FYC 2600H 60Co teletherapy unit by using ionization chamber RT101. That experimentally measured PDD values for both units were compared with published values in BJR supplement No 17. The experimentally measured values for CIRUS 60Co showed up to 0.8% deviation at maximum and that for MEDNIF 60Co showed up to 4.5% deviation at maximum. This study investigated the discrepancy between the BJR values and experimentally determined values for two teletherapy units in Nepal

  4. Effects of gamma irradiation of the 60 Co on antimicrobial action of plant extracts of bark and leaves of Schinus terebinthifolius Raddi

    International Nuclear Information System (INIS)

    This study aimed to evaluate the potential for antimicrobial activity in vitro of extracts of bark and leaves of S. terebinthifolius treated with 60Co gamma radiation. 5,0 doses were used; 7.5 and 10 kGy, being held non-irradiated controls. To determine the antimicrobial activity was applied to the disc diffusion technique to evaluate the diameter of the inhibition zones against Gram-positive bacteria, gram-negative bacteria, alcohol-acid-resistant and yeast. Antimicrobial activity was considered significant for halos ≥ 15 mm. The results indicate an intensification of antimicrobial action of bark extracts, the 5.0 kGy, against S. aureus. Was held the micro dilution in broth to determine the minimum inhibitory concentration (MIC) and Minimum Bactericidal Concentration (MBC) of peels extracts, compared to eight clinical isolates of S. aureus. The MBC values showed that ionizing radiation did not produce the increased of anti bacteriostatic action of S. terebinthifolius, but the results indicated that S. terebinthifolius bark extracts can be used as an antimicrobial agent and ionizing radiation as an important alternative in this conservation feature

  5. Optimization of process parameters for the inactivation of Lactobacillus sporogenes in tomato paste with ultrasound and {sup 60}Co-{gamma} irradiation using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Ye Shengying [College of Food Science, South China Agricultural University, Wushan, Guangzhou, GD 510640 (China)], E-mail: yesy@scau.edu.cn; Qiu Yuanxin; Song Xianliang; Luo Shucan [College of Food Science, South China Agricultural University, Wushan, Guangzhou, GD 510640 (China)

    2009-03-15

    The processing parameters for ultrasound and {sup 60}Co-{gamma} irradiation were optimized for their ability to inactivate Lactobacillus sporogenes in tomato paste using a systematic experimental design based on response surface methodology. Ultrasonic power, ultrasonic processing time and irradiation dose were explored and a central composite rotation design was adopted as the experimental plan, and a least-squares regression model was obtained. The significant influential factors for the inactivation rate of L. sporogenes were obtained from the quadratic model and the t-test analyses for each process parameter. Confirmation of the experimental results indicated that the proposed model was reasonably accurate and could be used to describe the efficacy of the treatments for inactivating L. sporogenes within the limits of the factors studied. The optimized processing parameters were found to be an ultrasonic power of 120 W with a processing time of 25 min and an irradiation dose of 6.5 kGy. These were measured under the constraints of parameter limitation, based on the Monte Carlo searching method and the quadratic model of the response surface methodology, including the a/b value of the Hunter color scale of tomato paste. Nevertheless, the ultrasound treatment prior to irradiation for the inactivation of L. sporogenes in tomato paste was unsuitable for reducing the irradiation dose.

  6. 60Co gamma-ray sterilization of natural nutritive lotion cream without preservative

    International Nuclear Information System (INIS)

    With a radiation dose of 6 kGy the 95% of bacteria in natural nutritive lotion cream could be killed. This dose gave no effect on physico-chemical properties and nutritive composition. The dose above this would have an effect on colloidal kinetics stability and the effect increased with increasing dose

  7. Cytotoxicity evaluation of Diethyltoluamide (DEET) in Perna perna (Linnaeus, 1758) mussels non-irradiated and irradiated with 60Co gamma radiation

    International Nuclear Information System (INIS)

    Recent studies have identified the presence of several emerging pollutants in aquatic environments. The occurrence in different environmental matrices has been continuously reported, highlighting the need for toxicity studies. The DEET (N,N-diethyl-meta-toluamide) is the active ingredient used in most insect repellents, and is present in many commercially available formulations. Apart from chemical pollutants, aquatic organisms are subject to exposure of ionizing radiation from natural sources or in the vicinity of nuclear power plants. The present study evaluated the toxicity of DEET in organisms irradiated and non-irradiated with 60Co gamma radiation, and the effects that radiation causes in lysosomes of hemocytes of Perna perna mussel. For this purpose, assays were performed to identify the acute toxicity of DEET concentration and the dose of gamma radiation able to cause mortality. Subsequently, cytotoxicity assays were carried out to assess the stability of the lysosomal membrane in organisms exposed to ionizing radiation and DEET. According to the results obtained in acute toxicity tests, the concentration of DEET that causes mortality of 50% exposed organisms (LC50) is 114,27 mg L-1, and the radiation dose that causes mortality (LD50) is 1068 Gy. In the cytotoxicity assays, the concentration of the non-observed effect (NOEC) for irradiated and non-irradiated organisms 0.0001 mg L-1 and observed effect concentration (LOEC) at concentrations above this. The IC25 (72h) for non-irradiated organisms was 0.0003 mg L-1 and IC50 (72h) was 0.0008 mg L-1 for irradiated and non-irradiated organisms. Despite of the concentrations of effect found in this study were higher than in the environment, both measurements are in the same order of magnitude and should be also take into account the possible synergistic effects of DEET with other contaminants in the aquatic environment. (author)

  8. Mutagenesis by gamma-rays in grain sorghum

    International Nuclear Information System (INIS)

    This study was undertaken to get information on irradiation - induced mutation in grain sorghum. Dry seeds of uniform size of three improved local varieties were irradiated with gamma-rays from 60Co source. Doses administered were 10, 20, 30 and 40 KR at the rate of 4.48 KR/minute. Observation for length, breadth and weight, of panicles grain yield etc were recorded and the data were statistically analysed. (author)

  9. 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.)

  10. Optimization of foaming properties of sludge protein solution by 60Co γ-ray/H2O2 using response surface methodology

    Science.gov (United States)

    Xiang, Yulin; Xiang, Yuxiu; Wang, Lipeng; Zhang, Zhifang

    2016-10-01

    Response surface methodology and Box-Behnken experimental design were used to model and optimize the operational parameters of foaming properties of the sludge protein solution by 60Co γ-ray/H2O2 treatment. The four variables involved in this research were the protein solution concentration, H2O2, pH and dose. In the range studied, statistical analysis of the results showed that selected variables had a significant effect on protein foaming properties. The optimized conditions contained: protein solution concentration 26.50% (v/v), H2O2 concentration 0.30% (v/v), pH value 9.0, and dose 4.81 kGy. Under optimal conditions, the foamability and foam stability approached 23.3 cm and 21.3 cm, respectively. Regression analysis with R2 value of 0.9923 (foamability) and 0.9922 (foam stability) indicated a satisfactory correlation between the experimental data and predicted values (response). In addition, based on a feasibility analysis, the 60Co γ-ray/H2O2 method can improve odor and color of the protein foaming solution.

  11. Differential Expression of Retrotransposon WIS 2-1A Response to Vacuum, Low-Energy N+ Implantation and 60Coγ-ray Irradiation in Wheat

    Science.gov (United States)

    Zhao, Huiru; Gu, Yunhong; Ya, Huiyuan; Jiao, Zhen; Qin, Guangyong

    2009-02-01

    Mutagenesis and retrotransposons have a close relationship, but little attention has been paid yet to the activity of retrotransposons produced by physical mutagens. The variation of retrotransposon WIS 2-1A activity in wheat (Triticum aestivum L.) embryos at three different growth times (30 h, 45 h and 60 h) was investigated after they had been treated with N+ implantation in a vacuum of 5 × 10-2 Pa and irradiation by 60Coγ-ray respectively. For each of the three growth times the expression of WIS 2-1A showed almost entirely a same trend of downregulation, upregulation, then downregulation, and upregulation again with the increase in dose of N+ implantation, but the expression appeared irregular with the increase in irradiation of 60Coγ-ray. In conclusion, the acutely activating effect of WIS 2-1A stimulated by vacuum and high dose N+ implantation within a shorter incubation time may provide a convenient tool to advance the research on mutagenic breeding and function genes.

  12. Differential Expression of Retrotransposon WIS 2-1A Response to Vacuum,Low-Energy N+ Implantation and 60Coγ-ray Irradiation in Wheat

    Institute of Scientific and Technical Information of China (English)

    ZHAO Huiru; GU Yunhong; YA Huiyuan; JIAO Zhen; QIN Guangyong

    2009-01-01

    Mutagenesis and retrotransposons have a close relationship,but little attention has been paid yet to the activity of rtrotransposons produced by physical mutagens. The variation of retrotransposon WIS 2-1A activity in wheat(Triticum aestivum L.)embryos at three different growth times(30 h,45 h and 60 h)was investigated after they had been treated with N+ implantation in a vacuum of 5x10-2 Pa and irradiation by 60Coγ-ray respectively.For each of the three growth times the expression of WIS 2-1A showed almost entirely a same trend of downregulation,upregulation,then downregulation,and upregulation again with the increase in dose of N+ implantation,but the expression appeared irregular with the increase in irradiation of 60Coγ-ray.In conclusion,the acutely activating effect of WIS 2-1A stimulated by vacuum and high dose N+ implantation within a shorter incubation time may provide a convenient tool to advance the research on mutagenic breeding and function genes.

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

    CERN Document Server

    Marisaldi, M; Trois, A; Giuliani, A; Tavani, M; Labanti, C; Fuschino, F; Bulgarelli, A; Longo, F; Barbiellini, G; Del Monte, E; Moretti, E; Trifoglio, M; Costa, E; Caraveo, P; Cattaneo, P W; Chen, A; D'Ammando, F; De Paris, G; Di Cocco, G; Di Persio, G; Donnarumma, I; Evangelista, Y; Feroci, M; Ferrari, A; Fiorini, M; Froysland, T; Galli, M; Gianotti, F; Lapshov, I; Lazzarotto, F; Lipari, P; Mereghetti, S; Morselli, A; Pacciani, L; Pellizzoni, A; Perotti, F; Picozza, P; Piano, G; Pilia, M; Prest, M; Pucella, G; Rapisarda, M; Rappoldi, A; Rubini, A; Sabatini, S; Soffitta, P; Striani, E; Vallazza, E; Vercellone, S; Vittorini, V; Zambra, A; Zanello, D; Antonelli, L A; Colafrancesco, S; Cutini, S; Giommi, P; Lucarelli, F; Pittori, C; Santolamazza, P; Verrecchia, F; Salotti, L; 10.1103/PhysRevLett.105.128501

    2010-01-01

    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 degrees at 50 MeV. Remarkably, all TGF-associated gamma rays are compatible with a terrestrial production site closer to the sub-satellite 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.

  14. Effects of 60Co γ-ray irradiation on microstructure and ferroelectric properties of Bi3.25La0.75Ti3O12 thin films

    Science.gov (United States)

    Wang, Zan; Jiang, Wei; Li, San-xi; Tong, Jun-sheng

    2016-01-01

    Bi3.25La0.75Ti3O12 (BLT) thin films were deposited on Pt/Ti/SiO2/Si substrates through sol-gel method. Films underwent 60Co γ-ray irradiation with different doses; 0, 50, 100 and 150 kGy, respectively. Impacts of γ-ray on the microstructure, ferroelectric properties, leakage current density and fatigue characteristic were studied in detail. The results of SEM images show that grain patterns become irregular. Remnant polarization (2Pr) and coercive field (2Ec) decrease with irradiation dose increase. C-V curves reveal obvious asymmetry along y-axis. The irradiated thin films display lower leakage current density and fatigue endurance up to more than 1010 switching cycles. These results suggest that radiation can improve the film performance in some areas.

  15. Rapid rejoining of DNA strand breaks in resting human lymphocytes after irradiation by low doses of 60Co γ rays or 14.6-MeV neutrons

    International Nuclear Information System (INIS)

    The production and repair of DNA strand breaks was studied in human lymphocytes by means of a sensitive fluorometric technique. Lymphocytes were isolated by conventional methods and air-equilibrated suspensions were irradiated by low doses (less than or equal to 2 Gy) of either 60Co γ rays or 14.6-MeV neutrons at 00C. The apparent yield of initial strand breaks induced by neutrons was only 36% of that induced by γ rays, in agreement with the observations of other workers. Resting lymphocytes were found to be proficient in their ability to rejoin γ-induced strand breaks at 370C; rejoining followed biphasic kinetics, with 70% of the breaks disappearing with a half-life of about 3 min. Although the initial number of breaks induced by neutron irradiation was low, after 20 min of incubation the residual number of breaks was very similar for the two forms of radiation

  16. Preparation and Characterization of Fe3O4 Magnetic Nano-particles by 60Co γ-ray Irradiation

    Institute of Scientific and Technical Information of China (English)

    Mingcheng YANG; Hongyan SONG; Chengshen ZHU; Suqin HE; Ya GAO

    2007-01-01

    By using a new method, 60C0 γ-ray irradiation, Fe3O4 magnetic nano-particles were successfully synthesized at room temperature under ambient pressure. The structure, morphology and magnetic properties of these nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM), respectively. The radiation formation mechanism was also discussed. The results show that the absorbed dose can greatly influence the structure, morphology and magnetic properties of the products. XRD and TEM studies show that the product prepared by γ-ray irradiation (10 kGy) is pure FesO4 phase and the mean diameter of these nano-particles is about 21 nm. The Fe3O4 nano-particles synthesized by γ-ray irradiation (10 kGy) are mainly in small cubic shape and the size uniformity of these particles is good.

  17. Fission prompt gamma-ray multiplicity distribution measurements and simulations at DANCE

    Energy Technology Data Exchange (ETDEWEB)

    Chyzh, A; Wu, C Y; Ullmann, J; Jandel, M; Bredeweg, T; Couture, A; Norman, E

    2010-08-24

    The nearly energy independence of the DANCE efficiency and multiplicity response to {gamma} rays makes it possible to measure the prompt {gamma}-ray multiplicity distribution in fission. We demonstrate this unique capability of DANCE through the comparison of {gamma}-ray energy and multiplicity distribution between the measurement and numerical simulation for three radioactive sources {sup 22}Na, {sup 60}Co, and {sup 88}Y. The prospect for measuring the {gamma}-ray multiplicity distribution for both spontaneous and neutron-induced fission is discussed.

  18. Applied gamma-ray spectrometry

    CERN Document Server

    Dams, R; Crouthamel, Carl E

    1970-01-01

    Applied Gamma-Ray Spectrometry covers real life application of the gamma-ray and the devices used in their experimental studies. This book is organized into 9 chapters, and starts with discussions of the various decay processes, the possible interaction mechanisms of gamma radiation with matter, and the intrinsic and extrinsic variables, which affect the observed gamma-ray and X-ray spectra. The subsequent chapters deal with the properties and fabrication of scintillation detectors, semiconductor detectors, and proportional gas counters. These chapters present some of the most widely utilized

  19. Morphology and properties of polyurethane/poly(ST) or poly(MMA) interpenetrating polymer networks by 60Co γ-ray

    International Nuclear Information System (INIS)

    Interpenetrating polymer networks (IPNs) are the mixture of two or more crosslinked polymers which are dispersed or mixed in the segmental level. In general, due to the low entropy of mixing, segmentally dispersed networks are difficult to be realized. It was able to increase further the degree of interpenetration in the incompatible PU-PMMA IPN by applying 60Co-γ radiation polymerization. By using the simultaneous polymerization process under radiation, a transparent, nearly segmentally dispersed mixture of the IPN was able to be obtained. The study on the IPN by small angle X-ray scattering and transmission electron microscopy showed that radiation-initiated polymerization is an effective means for obtaining the PU-PMMA IPN with high extent interpenetration. The IPN with two continuous phase structure was obtained. The materials used for the experiment, the method of synthesis, and the results of the morphology, glass transition and mechanical properties of the IPN are reported. (K.I.)

  20. 60Co-γ射线辐照育种马铃薯新品系鉴定试验%New Strains Identification of Potatos Breeded by 60Co-γRay Radiation

    Institute of Scientific and Technical Information of China (English)

    邓宽平; 丁海兵; 罗治霞; 夏锦慧

    2008-01-01

    对5个60Co-γ射线辐照育种马铃薯新品系进行了比较鉴定试验.结果表明:F8-02比对照品种费乌瑞它小区增产17.9 kg,增产率为79.2%,产量居第1位,F8-01比对照增产5.8 kg,增产率为25.7%,产量居第2位.小区产量居前两位的品系均比对照抗马铃薯晚疫病,且综合性状较好.

  1. 60Co γ-ray irradiation effect on germination and seedling growth of dry Buchloe dactyloides seeds

    International Nuclear Information System (INIS)

    The dry seeds of Buchloe dactyloides were irradiated by γ-ray at dose of 25-300 Gy. Seed germination and seedling characters were surveyed in laboratory and field. The results indicated that radiation could promote seed germination, and the optimum dose was 100 Gy. The dose of 150 Gy was the up limit to germination rate, root length and seedling height in field. When the radiation dose was bellow 100 Gy, the fresh weight of stems, leaves and roots of seedlings were increased. From this study, the recommended radiation does for Buchloe dactyloides dry seeds treatment was between 100-150 Gy for the purpose of promoting germination. (authors)

  2. Seeds of Camargue rice (Oryza Sativa L. Var Cigalon) and their responses to exposure to 60-Co gamma radiations. Study of the natural phenomenon of radiation protection

    International Nuclear Information System (INIS)

    Within the frame of a project aiming at improving a technique of experimental mutagenesis (seed processing by cobalt-60 gamma rays), this research thesis reports the radiobiological characterization of Cigalon rice seeds, the adjustment of techniques of radiation protection, and the definition of processing and irradiation conditions which could reduce the undesirable physiological effects of cobalt-60 gamma radiation on rice seeds. The author reports the study of variations of physiological radio-sensitivity. Damages are assessed by comparing the growth of irradiated seeds with that of non-irradiated seeds. The mechanism of radiation natural protection is studied by comparing an inhibition in distilled water at two temperatures (5 and 24 C) with that obtained with cysteamine (an efficient radiation protection compound)

  3. Airborne gamma-ray spectrometry

    DEFF Research Database (Denmark)

    Hovgaard, Jens

    A new method - Noise Adjusted Singular Value Decomposition, NASVD - for processing gamma-ray spectra has been developed as part of a Ph.D. project. By using this technique one is able to decompose a large set of data - for example from airborne gamma-ray surveys - into a few spectral components. ...

  4. IMMUNE TOLERANCE INDUCED BY GAMMA-RAY IRRADIATION

    Institute of Scientific and Technical Information of China (English)

    练燕; 王延江; 粟永萍; 冉新泽; 艾国平; 刘晓宏; 郭朝华; 程天民

    2003-01-01

    Objective: To detect the existence of immune tolerance induced by gamma-ray irradiation. Methods: Peritoneal cells were harvested from mice subjected to 5 Gy 60Co gamma-ray total body irradiation at 3d, 7d, 15d and 30d, then their counts, morphological changes and IL-12 gene expression were investigated. Results: After irradiation, the peritoneal cells were sharply reduced, the cell morphology shifted from round-like to polymorphic and fusiform with some processes, expression of IL-12 p35 was seriously suppressed, while that of IL-12 p40 greatly enhanced. Conclusion: Our data highly suggest that the gamma-ray irradiation could potentially induce dendritic cell (DC) commitment and immune tolerance.

  5. 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

  6. Planetary gamma-ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Reedy, R.C.

    1978-01-01

    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.

  7. KEY COMPARISON: Comparison of the standards for absorbed dose to water of the ENEA-INMRI (Italy) and the BIPM for 60Co γ rays

    Science.gov (United States)

    Kessler, C.; Allisy-Roberts, P. J.; Burns, D. T.; Guerra, A. S.; Laitano, R. F.; Pimpinella, M.

    2010-01-01

    A comparison of the standards for absorbed dose to water of the Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti of the Ente per le Nuove Tecnologie, l'Energia e l'Ambiente, Italy (ENEA-INMRI), and of the Bureau International des Poids et Mesures (BIPM) has been made in 60Co gamma radiation under the auspices of the key comparison BIPM.RI(I)-K4. The comparison result, based on the calibration coefficients for three transfer standards and expressed as a ratio of the ENEA and the BIPM standards for absorbed dose to water, is 0.9999 (0.0044). The present 2007 result replaces the earlier ENEA value in this key comparison. The degrees of equivalence between the ENEA and the other participants in this comparison have been calculated and the results are given in the form of a matrix for the ten national metrology institutes (NMIs) that have published results in this ongoing comparison for absorbed dose to water. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section I, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  8. Thermal stability of formulations of PVC irradiated with {gamma} of {sup 60}; Estabilidad termica de formulaciones de PVC irradiadas con {gamma} de {sup 60} Co

    Energy Technology Data Exchange (ETDEWEB)

    Martinez P, M.E.; Carrasco A, H. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico)]. E-mail: memp@nuclear.inin.mx; Castaneda F, A.; Benavides C, R.; Garcia R, S.P. [CIQA, 25100 Saltillo, Coahuila (Mexico)

    2004-07-01

    The industry of cables and wires frequently use cable isolations with base of formulations of PVC, in those that stabilizer has usually been used with the help of heavy metals, as the lead, which is toxic. To solve the problem, from the 2002 one has come studying in combined form in the National Institute of Nuclear Research ININ and the Center of Investigation in Applied Chemistry CIQA, the modifications induced by the radiation in formulations with the help of vinyl poly chloride PVC. In these formulations, prepared with cross linking agent, plastifying industrial grade, stuff and non toxic stabilizers of calcium estearate and zinc industrial grade, it is sought to replace the stabilizer of Pb. For this were irradiated it test tubes of PVC with gamma radiation of cobalt 60 to three different dose in atmospheres of air and argon. Later it was determined their thermal stability at different times of heating and it was measured the Young modulus by means of thermo mechanical analysis. Those results obtained together with other techniques of characterization suggest that the irradiated proposed formulation can substitute the one stabilized with lead. (Author)

  9. Effects of Pre-exposure of Mouse Pituitary with Low-dose 60Co γ-ray on Male Reproductive Endocrine Capacity Induced by Subsequent High-dose Irradiation

    Institute of Scientific and Technical Information of China (English)

    ZhangHong; LiWenjian; JingXiaodong; LiuBing; MinFengling; ZhouQingming; XieYi

    2003-01-01

    To investigate the effects of pre-exposure of mouse pituitary with low-dose 60Co γ-ray on male reproductive endocrine capacity induced by subsequent high-dose irradiation, the pituitary of the B6C3F1 hybrid strain male mice were irradiated with 0.05 Gy of 60Co γ-ray as the pre-exposure dose (D1), and were then irradiated with 2 Gy of 60Co γ-ray as challenging irradiation dose (D2) at 4 h after per-exposure. Pituitary gonadotroping hormones --follicle-stimulating hormone (FSH) and luterinzing hormone (LH), serum testosterone, testis weight and sperm count were measured at 35th day after irradiation.

  10. 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.)

  11. 60Co-γ射线辐射对胭脂虫Dactylopius coccus Costa生物学特征的影响%The Research on Biological Characteristics of Cochineal (Dactylopius coccus Costa) Radiated by 60CoRay

    Institute of Scientific and Technical Information of China (English)

    陈海游; 张忠和; 秦志虹; 张海涛

    2014-01-01

    利用60Co-γ射线对胭脂虫孕卵期进行辐射试验,探讨60Co对胭脂虫生物学特征的影响.结果表明,高剂量(3000rad以上)辐射胭脂虫造成其子代性比严重失调,雄虫几乎为0,无法进行有性生殖,导致无法产生后代,高剂量辐射对雄虫的损伤极大.低剂量辐射(特别是500rad)下F1较对照:各龄级虫口数提高;成虫期雌虫数明显高于对照,雄虫数略高;孵化量、孵化率提高;单株雌成虫鲜重、干重均明显增重;怀卵量大幅增多;雌成虫个体鲜干重、鲜干比、体积无差异.对于500rad辐射的胭脂虫,F2在有效生殖率、鲜干重和鲜干比方面效果较F1还好,存在优势显效滞后现象.但连续培育3代后,与对照已无差异.

  12. Gamma-ray Pulsar Revolution

    OpenAIRE

    Caraveo, Patrizia A.

    2013-01-01

    Isolated Neutron Stars (INSs) were the first sources identified in the field of high-energy gamma-ray astronomy. At first, in the 70s, there were only two identified sources, 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 both in the theoretical and phenomenological fronts. The need to explain the copious gamma-ray emission of these pulsars led t...

  13. Effect of 60Co γ-ray Irradiation on Growth Characteristics of Chamaecrista%60Co-γ射线辐照处理对决明若干生长特性的影响

    Institute of Scientific and Technical Information of China (English)

    翁伯琦; 徐国忠; 郑向丽; 应朝阳; 黄毅斌

    2005-01-01

    利用60℃o-γ射线(辐照剂量为300 Gy,剂量率为4.687 5 Gy/min)辐照豆科决明属5个牧草品种的种子,通过盆栽收集各个品种的M1代种子,然后进行M2代试验与观察.结果表明,辐照后5个决明M2代的种子出苗率、植株的茎长、叶宽均无显著差异;34721号决明植株冠高有显著增长、2219号决明茎径有显著增长、86134号决明分枝数有极显著增长,92985号决明分枝数则有显著降低、86134号决明叶数和地上部植株干重有显著增长、2219号决明叶长增长显著,其余参试品种则无显著差异.植株的营养成分测定表明:仅2219号决明K含量呈显著下降、其他品种的N,P,K含量则无显著差异;2219不仅氨基酸总量呈显著下降、而且17种氨基酸都表现为不同程度的下降,86134氨基酸总量有显著增长、同时17种氨基酸都表现为不同程度的增长,而其余3个参试品种都无显著差异.经60Co-γ射线辐照处理后的34721,86134,92985的酯酶同工酶谱与相应的对照有明显差别.生长观察结果表明,参试的5个决明品种M2代植株生长的现蕾期、初花期、盛花期、初荚期、盛荚期、成熟期表现为双向性,既有提早,也有推迟.

  14. Gamma-ray-selected AGN

    Science.gov (United States)

    Giommi, Paolo

    2016-08-01

    The gamma-ray band is the most energetic part of the electromagnetic spectrum. As such it is also where selection effects are most severe, as it can only be reached by the most extreme non-thermal AGN. Blazars, with their emission dominated by non-thermal blue-shifted radiation arising in a relativistic jet pointed in the direction of the observer, naturally satisfy this though requirement. For this reason, albeit these sources are intrisically very rare (orders of magnitude less abundant than radio quiet AGN of the same optical magnitude) they almost completely dominate the extragalactic gamma-ray and very high energy sky. I will discuss the emission of different types of blazars and the selection effects that are at play in the gamma-ray band based on recent results from the current generation of gamma-ray astronomy satellites, ground-based Cherenkov telescopes, and Monte Carlo simulations.

  15. Effects of Pre-exposure Mouse Pituitary with Low-dose 60Co γ-ray on Growth Hormone (GH) and Body Mass Induced by Subsequent High-dose Irradiation

    Institute of Scientific and Technical Information of China (English)

    ZhangHong; LiWenjian; JingXiaodong; LiuBing; MinFengling; ZhouQingming; XieYi

    2003-01-01

    The pituitary of the B6C3F1 hybrid strain mice were irradiated with 0.05 Gy of 60Co γ-ray as the pre-exposure dose (D1), and were then irradiated with 2 Gy of 60Co γ-ray as challenging irradiation dose (D2) at 4h after per-exposure. Body weight and serum growth hormone (GH) were measured at 35th day after irradiation. The results showed that irradiation of mouse testes with 2 Gy of 60Co γ-ray significantly diminished mousebody weight and level of serum GH (Table). Pre-exposure with a low-dose (0.05 Gy) of 60Co γ-ray significantly alleviated reductions of mouse body weight and level of serum GH induced by subsequent a high-dose (2 Gy) irradiation (Table). The data suggested that low-dose ionizing irradiation can induce adaptive responses to the harmful effects of pituitary by subsequent high-dose exposure.

  16. A comparison of the biological effects of 125I seeds continuous low-dose-rate radiation and 60Co high-dose-rate gamma radiation on non-small cell lung cancer cells.

    Directory of Open Access Journals (Sweden)

    Zhongmin Wang

    Full Text Available To compare the biological effects of 125I seeds continuous low-dose-rate (CLDR radiation and 60Co γ-ray high-dose-rate (HDR radiation on non-small cell lung cancer (NSCLC cells.A549, H1299 and BEAS-2B cells were exposed to 125I seeds CLDR radiation or 60Co γ-ray HDR radiation. The survival fraction was determined using a colony-forming assay. The cell cycle progression and apoptosis were detected by flow cytometry (FCM. The expression of the apoptosis-related proteins caspase-3, cleaved-caspase-3, PARP, cleaved-PARP, BAX and Bcl-2 were detected by western blot assay.After irradiation with 125I seeds CLDR radiation, there was a lower survival fraction, more pronounced cell cycle arrest (G1 arrest and G2/M arrest in A549 and H1299 cells, respectively and a higher apoptotic ratio for A549 and H1299 cells than after 60Co γ-ray HDR radiation. Moreover, western blot assays revealed that 125I seeds CLDR radiation remarkably up-regulated the expression of Bax, cleaved-caspase-3 and cleaved-PARP proteins and down-regulated the expression of Bcl-2 proteins in A549 and H1299 cells compared with 60Co γ-ray HDR radiation. However, there was little change in the apoptotic ratio and expression of apoptosis-related proteins in normal BEAS-2B cells receiving the same treatment.125I seeds CLDR radiation led to remarkable growth inhibition of A549 and H1299 cells compared with 60Co HDR γ-ray radiation; A549 cells were the most sensitive to radiation, followed by H1299 cells. In contrast, normal BEAS-2B cells were relatively radio-resistant. The imbalance of the Bcl-2/Bax ratio and the activation of caspase-3 and PARP proteins might play a key role in the anti-proliferative effects induced by 125I seeds CLDR radiation, although other possibilities have not been excluded and will be investigated in future studies.

  17. Comunicación corta. RADIOESTIMULACIÓN DE LA GERMINACIÓN EN Stevia rebaudiana CULTIVAR KH-IAN VC-142 (EIRETÉ), MEDIANTE EL EMPLEO DE RAYOS GAMMA 60CO

    OpenAIRE

    María C. González; Héctor D. Nakayama

    2015-01-01

    El presente trabajo tuvo como objetivo evaluar el efecto de bajas dosis de rayos gamma 60 Co en la germinación de las semillas de Stevia rebaudiana . Para ello se irradiaron semillas del cultivar KH-IAN VC-142 (Eireté), con dosis de 10 a 90 Gray (Gy). Se determinó que todas las dosis empleadas incrementaron el número de semillas germinadas pero la dosis de 10 Gy fue la que provocó la mayor estimulación en la germinación de las semillas.

  18. Comunicación corta. RADIOESTIMULACIÓN DE LA GERMINACIÓN EN Stevia rebaudiana CULTIVAR KH-IAN VC-142 (EIRETÉ, MEDIANTE EL EMPLEO DE RAYOS GAMMA 60CO

    Directory of Open Access Journals (Sweden)

    María C. González

    2015-01-01

    Full Text Available El presente trabajo tuvo como objetivo evaluar el efecto de bajas dosis de rayos gamma 60 Co en la germinación de las semillas de Stevia rebaudiana . Para ello se irradiaron semillas del cultivar KH-IAN VC-142 (Eireté, con dosis de 10 a 90 Gray (Gy. Se determinó que todas las dosis empleadas incrementaron el número de semillas germinadas pero la dosis de 10 Gy fue la que provocó la mayor estimulación en la germinación de las semillas.

  19. 大剂量rhG-CSF早期单次给药对60Coγ射线照射小鼠的治疗作用%Therapeutic effects of early administration of a single high dose of rhG-CSF on mice irradiated by 60Coγ rays

    Institute of Scientific and Technical Information of China (English)

    韩阿如娜; 余祖胤; 柳晓兰; 从玉文

    2011-01-01

    Objective To observe the therapeutic effects of early administration with a single high dose of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on mice irradiated with 60Co γ rays, and provide a reference for the treatment of acute radiation syndrome (ARS) by using cytokines. Methods Male C57 mice underwent a total body irradiation of 8. Ogy 60Co y ray, and they were treated with rhG-CSF, at 0.5h and 24h, subcutaneously in a dose of 2, 1 and 0. 5mg/kg, respectively. The 30-day survival rate and mean survival time were observed in the lethal irradiated mice. The peripheral blood cell counts and bone marrow nucleated cell counts were evaluated in the sublethally irradiated mice. Results Early administration of a high dose of rhG-CSF significantly increased 30-day survival rate and prolonged mean survival time of mice with lethal irradiation dose. A single injection of rhG-CSF (lmg/kg) at 0. 5h after irradiation was an optimal administration schedule. In addition, early administration with a single high dose of rhG-CSF improved the recovery of bone marrow nucleated cell counts and peripheral blood counts, including white blood cell (WBC), red blood cell (RBC) and platelet in mice exposed to 6. Ogy irradiation. Conclusion Early administration of a single high dose rhG-CSF may have a favorable therapeutic effect on mice irradiated with 60Co y ray.%目的 观察大剂量rhG-CSF早期单次给药对60Coγ射线照射小鼠的治疗作用,为细胞因子治疗急性放射病提供实验依据.方法 雄性C57小鼠,经8.0Gy 60Co γ射线全身照射后于0.5、24h各皮下注射一次不同剂量rhG-CSF(2、1mg/kg和0.5mg/kg),观察致死剂量照射小鼠的30d存活率及平均生存时间.小鼠经6.0Gy 60Co γ射线全身照射后,通过不同给药方案及不同剂量rhG-CSF早期干预,观察亚致死剂量照射小鼠的外周血象和骨髓有核细胞数的变化.结果 大剂量rhG-CSF早期干预明显提高致死剂量照射小鼠的30d存

  20. Extragalactic Gamma-Ray Astrophysics

    CERN Document Server

    CERN. Geneva

    2016-01-01

    During the last decades, various classes of radio-loud active galactic nuclei have been established as sources of high-energy radiation extending over a very broad range from soft gamma-rays (photon energies E~MeV) up to very-high-energy gamma-rays (E>100 GeV). These include blazars of different types, as well as young and evolved radio galaxies. The observed gamma-ray emission from such implies efficient particle acceleration processes taking place in highly magnetized and relativistic jets produced by supermassive black holes, processes that have yet to be identified and properly understood. In addition, nearby starforming and starburst galaxies, some of which host radio-quiet Seyfert-type nuclei, have been detected in the gamma-ray range as well. In their cases, the observed gamma-ray emission is due to non-thermal activity in the interstellar medium, possibly including also a contribution from accretion disks and nuclear outflows. Finally, the high-energy emission from clusters of galaxies remains elusive...

  1. Possible s-process gamma ray lines in supernovae

    International Nuclear Information System (INIS)

    The authors calculate the abundances in the helium burning shells of presupernova stellar models by Woosley and Weaver (1986 a,b). For stellar masses above ≅ 20 M circle the 22Ne(α,n)25Mg reaction produces enough neutrons on a sufficiently short time-scale for the s-process to produce 59Fe (1/2 = 45 d) and 60Co (1/2 = 5.3 yr). These isotopes are expected to survive the passage of the shock, and gamma rays from their decays should be detectable from most Galactic Type II supernovae with the Gamma Ray Observatory (GRO) Compton telescope. The calculated abundances of these nuclei in the helium zone are shown as functions of helium-burning temperature

  2. Key comparison BIPM.RI(I)-K1 of the air-kerma standards of the NIM, China and the BIPM in 60Co gamma radiation

    Science.gov (United States)

    Kessler, C.; Burns, D.; Wang, K.; Fan, Y.; Jin, S.; Yang, X.

    2016-01-01

    An indirect comparison of the standards for air kerma of the National Institute of Metrology (NIM), China and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 60Co radiation beam of the BIPM in November 2015. The comparison result, evaluated as a ratio of the NIM and the BIPM standards for air kerma, is 0.9997 with a combined standard uncertainty of 2.7 × 10-3. The results are analysed and presented in terms of degrees of equivalence for entry in the BIPM key comparison database. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  3. Terrestrial gamma-ray flashes

    Energy Technology Data Exchange (ETDEWEB)

    Marisaldi, Martino, E-mail: marisaldi@iasfbo.inaf.it [INAF-IASF Bologna, Via Gobetti 101, I-40129 Bologna (Italy); Fuschino, Fabio; Labanti, Claudio [INAF-IASF Bologna, Via Gobetti 101, I-40129 Bologna (Italy); Tavani, Marco [INAF-IASF Roma, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Argan, Andrea [INAF, Viale del Parco Mellini 84, 00136 Roma (Italy); Del Monte, Ettore [INAF-IASF Roma, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Longo, Francesco; Barbiellini, Guido [Dipartimento di Fisica Università di Trieste and INFN Trieste, via A. Valerio 2, I-34127 Trieste (Italy); Giuliani, Andrea [INAF-IASF Milano, Via Bassini 15, I-20133 Milano (Italy); Trois, Alessio [INAF Osservatorio Astronomico di Cagliari, loc. Poggio dei Pini, strada 54, I-09012 Capoterra (Italy); Bulgarelli, Andrea; Gianotti, Fulvio; Trifoglio, Massimo [INAF-IASF Bologna, Via Gobetti 101, I-40129 Bologna (Italy)

    2013-08-21

    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. 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.

  5. Gamma ({sup 60}CO) radiation effects on arcelin protein and evaluation of bean lineages against Acanthoscelides obtectus (Say) and Zabrotes subfasciatus (Boh.) (Col.: Bruchidae);Efeito da radiacao gama ({sup 60}CO) sobre a proteina arcelina e avaliacao de linhagens de feijoeiro a Acanthoscelides obtectus (Say) and Zabrotes subfasciatus (Boh.) (Col.: Bruchidae)

    Energy Technology Data Exchange (ETDEWEB)

    Botelho, Ana Claudia Girardo

    2006-07-01

    The resistance of arcelin carrying seeds of bean lineages (Phaseolus vulgaris L.) against the bean weevils Acanthoscelides obtectus (Say, 1831) and Zabrotes subfasciatus (Bohemann, 1833) (Coleoptera: Bruchidae), and the influence of gamma radiation ({sup 60}CO) on the manifestation of arcelin resistance to Z. subfasciatus were verified. Laboratorial tests, in choice and non-choice tests, with wild specimens carrying Arc-1, Arc-2, Arc-3, Arc-4, Raz-56 and Raz-59 (with Arc-5 alleles) and commercial lineages as control IAC - Carioca and IAC - Arua were conducted. Statistical design was completely randomized, with five repetitions, with 10 g of grains from each lineage samples by portion. Attractiveness, oviposition, emergence, mortality, adults' weigh and longevity, developing period, sexual rate, seeds' weigh loss, infestation and fecundity (Z. subfasciatus) were observed. Gamma radiation doses irradiations, in general, haven't affected the resistance manifestation of lineages carrying arcelin protein variants against the Z. subfasciatus bean weevil, thus, joint application use of both control methods can be recommended. Raz-56 lineage showed high resistance of the antibiosis types and non-preference for oviposition and feeding to Z. subfasciatus, while Raz-59 showed antibiosis and non-preference for feeding, and both (Raz-56 and Raz-59) showed intermediate resistance to A. obtectus, against which lineage Arc-2 was the most harmful to its development, expressing non-preference to feeding and/or antibiosis. (author)

  6. Gamma rays in thunderstorms

    International Nuclear Information System (INIS)

    Not only lightning occur in thunderstorms but also luminous flashes that are emitted upwards over the clouds. These flashes have been studied for 20 years. Satellites have detected gamma flashes with an energy of 30 MeV. It was thought that these flashes resulted from collisions between cosmic particles and cloud molecules but recent results from the Italian Agile satellite question this explanation. Gamma flashes with an energy of 100 MeV have been detected which is too high an energy to be explained by collisions with cosmic particles. Another result show the existence of very strong acceleration of electrons in areas where some type of flashes are likely to happen. (A.C.)

  7. 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.

  8. Gamma-ray burst spectra

    Science.gov (United States)

    Teegarden, B. J.

    1982-01-01

    A review of recent results in gamma-ray burst spectroscopy is given. Particular attention is paid to the recent discovery of emission and absorption features in the burst spectra. These lines represent the strongest evidence to date that gamma-ray bursts originate on or near neutron stars. Line parameters give information on the temperature, magnetic field and possibly the gravitational potential of the neutron star. The behavior of the continuum spectrum is also discussed. A remarkably good fit to nearly all bursts is obtained with a thermal-bremsstrahlung-like continuum. Significant evolution is observed of both the continuum and line features within most events.

  9. 6Co γ射线诱发小鼠DNA甲基化改变%DNA methylation changes induced by 60 Co γ-ray irradiation

    Institute of Scientific and Technical Information of China (English)

    黄铖铖; 孙秀锦; 胡明江; 程跃进; 古桂雄; 崔凤梅

    2011-01-01

    Objective To study the change and significance of DNA methylation pattern and DNA methyltransferase (DNMT1) protein in 60Co γ-ray irradiated mice tissues. Methods Twelve SPF C57BL/6J mice were randomly divided in-tocontrol group and radiation group. The radiation group were exposed to 4Gy-single whole body radiation. All mice were sacrificed 3 days after the radiation. The total number of peripheral white blood cells and the frequencies of micronucleated polychromatic erythocytes(fMNPCE) were measured. Methylated DNA immunoprecipitation-chip(MeDIP-chip) was adopted to investigate the differentially expressed CpG islands methylation profiles in mouse liver genome promoter. The immunohisto-chemical(SP method) and western blot method were used to check the expression of DNMT1 protein in tissues. Results Compared with the control group,the promoter methylation profiles of irradiated mice changed obviously, with 1300 genes methylated and 660 genes demethylated. With the improvement of the screening criteria,the obviously methylated genes were Trim71,Sema3f, Pcdh8,Sox4,1110034A24Rik, Limkl, Nefl, and Xprl and the demethylated genes were Sfrsl8,Drl, Ankrd42,Nael ,Sfil ,Accnl ,Srd5al ,Nsun2,Eifla,and Dusp5. Except in the lung,the expression of DNMT1 protein in liver, kidney, testicle, and brain tissues were all increased (P < 0.05). Conclusion There are methylation changes of gene promoter in ionizing radiation injury and the increased expression of DNMT1 may be the reason of gene promoter methylation.%目的 探讨基因组启动子甲基化谱及DNA甲基化酶1(DNMT1)表达量在60Co-γ射线照射小鼠各组织的变化及其意义.方法SPF级C57BL/6J雄性小鼠12只随机分为对照组和照射组,照射组小鼠接受4Gy60 Co-y射线单次全身照射后,均眼球摘除取血后处死,收集各脏器组织,进行外周血白细胞计数和骨髓嗜多染红细胞微核计数,应用甲基化DNA免疫沉淀-芯片(MeDIP-chip)杂交技术对y射线

  10. Key comparison BIPM.RI(I)-K4 of the absorbed dose to water standards of the PTB, Germany and the BIPM in 60Co gamma radiation

    Science.gov (United States)

    Kessler, C.; Burns, D. T.; Kapsch, R.-P.; Krauss, A.

    2016-01-01

    An indirect comparison has been made of the standards for absorbed dose to water in 60Co radiation of the Physikalisch-Technische Bundesanstalt, (PTB), Germany and of the Bureau International des Poids et Mesures (BIPM). The measurements at the BIPM were carried out in October 2015. The comparison result, based on the calibration coefficients for two transfer standards and evaluated as a ratio of the PTB and the BIPM standards for absorbed dose to water, is 0.9977 with a combined standard uncertainty of 3.8 × 10-3. The results are analysed and presented in terms of degrees of equivalence for entry in the BIPM key comparison database. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  11. Neutrinos from Gamma Ray Bursts

    CERN Document Server

    Mannheim, K

    2000-01-01

    The observed fluxes of cosmic rays and gamma rays are used to infer the maximum allowed high-energy neutrino flux allowed for Gamma Ray Bursts (GRBs), following Mannheim, Protheroe, and Rachen (2000). It is shown that if GRBs produce the ultrahigh-energy cosmic rays, they should contribute (a) at least 10% of the extragalactic gamma ray background between 3 MeV and 30 GeV, contrary to their observed energy flux which is only a minute fraction of this flux, and (b) a cumulative neutrino flux a factor of 20 below the AMANDA (Neutrino 2000) limit on isotropic neutrinos. This could have two implications, either GRBs do not produce the ultrahigh energy cosmic rays or that the GRBs are strongly beamed and emit most of their power at energies well above 100 GeV implausibly increasing the energy requirements, but consistent with the marginal detections of a few low-redshift GRBs by MILAGRITO, HEGRA-AIROBICC, and the Tibet-Array. All crucial measurements to test the models will be available in the next few years. Thes...

  12. Novae in gamma-rays

    CERN Document Server

    Hernanz, M

    2013-01-01

    Classical novae produce radioactive nuclei which are emitters of gamma-rays in the MeV range. Some examples are the lines at 478 and 1275 keV (from 7Be and 22Na) and the positron-electron annihilation emission (511 keV line and a continuum below this energy, with a cut-off at 20-30 keV). The analysis of gamma-ray spectra and light curves is a potential unique and powerful tool both to trace the corresponding isotopes and to give insights on the properties of the expanding envelope determining its transparency. Another possible origin of gamma-rays is the acceleration of particles up to very high energies, so that either neutral pions or inverse Compton processes produce gamma-rays of energies larger than 100 MeV. MeV photons during nova explosions have not been detected yet, although several attempts have been made in the last decades; on the other hand, GeV photons from novae have been detected in some particular novae, in symbiotic binaries, where the companion is a red giant with a wind, instead of a main ...

  13. Gamma ray slush hydrogen monitor

    Science.gov (United States)

    Singh, Jag J.; Shen, Chih-Peng; Sprinkle, Danny R.

    1992-01-01

    Mass attenuation for 109Cd radiation have been measured in mixtures of phases and in single phases of five chemical compounds. As anticipated, the mass attenuation coefficients are independent of the phases of the test chemicals. It is recommended that a slush hydrogen monitoring system based on low energy gamma ray attenuation be developed for utilization aboard the NASP.

  14. Short duration gamma ray bursts

    Indian Academy of Sciences (India)

    Patrick Das Gupta

    2004-10-01

    After a short review of gamma ray bursts (GRBs), we discuss the physical implications of strong statistical correlations seen among some of the parameters of short duration bursts (90 < 2 s). Finally, we conclude with a brief sketch of a new unified model for long and short GRBs.

  15. GAMMA-RAY AND X-RAY EMISSION FROM GAMMA-RAY-LOUD BLAZARS

    Institute of Scientific and Technical Information of China (English)

    ZHANG XIONG; ZHAO GANG; XIE GUANG-ZHONG; ZHENG GUANG-SHENG; ZHANG LI

    2001-01-01

    We present a strong correlation of the gamma-ray (above 100 MeV) mean spectral indices aγ and X-ray (1 keV)mean spectral indices cX for 34 gamma-ray-loud blazars (16 BL Lac objects and 18 flat spectrum radio quasars). Astrong correlation is also found between the gamma-ray flux densities F-γ and X-ray flux densities Fx in the low state for 47 blazars (17 BL Lac and 30 flat spectrum radio quasars). Possible correlation on the gamma-ray emission mechanism is discussed. We suggest that the main gamma-ray radiation mechanism is probably the synchrotron process. The gamma-ray emission may be somewhat different from that of BL Lac objects and flat spectrum radio quasars.

  16. 125I粒子和60Co γ射线照射对A549及BEAS-2B细胞生物学效应的影响%The biological effects of 125I seeds and 60Co γ-rays on A549 and BEAS-2B cells

    Institute of Scientific and Technical Information of China (English)

    赵真真; 茅爱武; 王忠敏; 刘芬菊; 曹燕; 贾一平

    2015-01-01

    目的 探讨125I粒子和60Co γ射线对非小细胞肺癌(NSCLC) A549细胞和正常支气管上皮BEAS-2B细胞生物学效应的影响.方法 A549、BEAS-2B细胞均行125I粒子和60Coγ射线不同剂量照射;集落形成实验检测细胞存活分数;流式细胞术检测细胞周期和细胞凋亡率;Western blot检测凋亡相关蛋白的表达水平.结果 A549细胞在4、6、8 Gy照射时,125I粒子组细胞克隆存活分数较60Co组降低更明显(t=6.06、9.42、4.90,P<0.05).A549细胞在4 Gy时,G1期细胞比例125I粒子组为70.67%±1.49%,60Co组为59.59% ±0.71%(t=10.77,P<0.05);细胞凋亡率125I粒子组为18.09%±0.73%,60Co组为9.81%±0.16%(t=19.40,P<0.05).125I粒子照射明显上调Bax、cleaved Caspase-3蛋白的表达,同时下调Bcl-2蛋白的表达.但不同射线同一剂量或相同射线不同剂量下,BEAS-2B细胞的凋亡率及凋亡相关蛋白的表达无明显变化.结论 125I粒子持续低剂量率照射较60Co γ射线高剂量率照射抑制A549细胞增殖的效应更明显.Bcl-2/Bax蛋白比失衡,最终致Caspase-3蛋白的活化在125I粒子持续低剂量率照射抑制肿瘤细胞增殖的效应中可能发挥重要的作用.%Objective To investigate the biological effects of 125I seeds and 60Co γ-rays on the non-small cell lung cancer cells A549 and the normal bronchial epithelium cells BEAS-2B.Methods A549 and BEAS-2B cells were irradiated with 125I seeds and 60Co γ-rays.The survival fraction was detected by colony formation assay.The cell cycle and cell apoptotic ratio were detected by flow cytometry.The expression of cell apoptotic related proteins was examined by western blot.Results After irradiation with different doses,the survival of A549 cells irradiated with 125I seeds was lower than that irradiated with γ-rays (t =6.06,9.42,4.90,P <0.05).After irradiation with 4 Gy of 125I seeds and 60Co γ-rays,the G1 phase percentages of A549 cells were 70.67% ± 1.49% and 59.59% ± 0

  17. Radiation Effects of 60Co γ-Rays on Expression of CDKN1A mRNA in Human Lymphocytoblast%60Co γ射线照射正常人淋巴母细胞诱导CDKN1A基因mRNA表达水平的变化

    Institute of Scientific and Technical Information of China (English)

    朱昊; 施展; 何颖; 沈先荣; 王国卿

    2011-01-01

    Objective To study effect of 60Co γ-rays radiation with different doses on expression of CDKN1A gene mRNA in human lymphocytoblasl cultured for different time. Methods After human lym-phocytoblasts were irradiated by the 60Co γ-rays with various doses of 0, 0. 2, 1,3,5 and 10 Gy,and cells were separately cultured for sustaining survival during 0, 4, 24, 48, 72 and 96 h. The total RNA was extracted from each sample and the real-time PCR was conducted to observe the gene CDKN1A mR-NA level changes in lymphocytoblasts exposed to various radiation doses for various cultured time. Results Expressive levels of the CDKNIA mRNA in lymphocytoblasts gradually went up with increasing radiation doses, which showed γ-rays dose dependent from 0 Gy to 5 Gy (P <0. 05), and reach the peak when cells were cultured for 24 h after exposing to radiation while displayed an expressive downtrend during the later stage of cell culture. Conclusion Increase of the CDKN1A mRNA expression level in human lymphocytoblasts after exposing to 60Co γ-rays radiation within 24 hours of culture shows a dose dependent way, which may be used to evaluate the ionizing radiation dose.%目的 探讨不同剂量60Co γ射线在不同培养时间后对人淋巴母细胞AHH-1细胞CDKNIA基因mRNA表达的影响.方法 用不同剂量(0、0.2、1、3、5、10Gy)的60Coγ射线照射正常人淋巴母细胞AHH-1细胞,在不同维持存活培养时间(0、4、24、48、72、96 h)内收集细胞,抽提总RNA,用实时PCR方法检测细胞中CDKNIA基因mRNA表达水平,观察其随辐照剂量和培养时间的变化.结果 AHH-1细胞中CDKN1A基因 mRNA的表达水平随辐照剂量的加大而增加,在0~5Gy之间具有一定剂量依赖性关系(P<0.05);辐照后培养24 h时基因表达达到峰值,24h之后呈现下降趋势.结论 不同剂量γ射线照射人AHH-1细胞会导致CDKNIA基因表达水平在培养24h内随辐射剂量增加而升高,这种剂量依赖性关系可能适用于电离辐射剂量的估算.

  18. Effects of gamma irradiation of the {sup 60} Co on antimicrobial action of plant extracts of bark and leaves of Schinus terebinthifolius Raddi; Efeitos da radiacao gama do {sup 60} Co sobre a acao antimicrobiana de extratos vegetais de cascas e folhas de Schinus terebinthifolius Raddi

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Edvane Borges da; Santos, Gustavo Henrique Farias dos; Amaral, Ademir de Jesus [Universidade Federal da Pernambuco (GERAR/DEN/UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia; Lima, Jeniffer Maiza de Souza [Universidade Federal da Pernambuco (CAV/UFPE), Vitoria de Santo Antao, PE (Brazil); Xisto, Kesia; Araujo, Rosilma de Oliveira [Universidade Federal da Pernambuco (DA/UFPE), Recife, PE (Brazil). Dept. de Antibioticos

    2014-07-01

    This study aimed to evaluate the potential for antimicrobial activity in vitro of extracts of bark and leaves of S. terebinthifolius treated with {sup 60}Co gamma radiation. 5,0 doses were used; 7.5 and 10 kGy, being held non-irradiated controls. To determine the antimicrobial activity was applied to the disc diffusion technique to evaluate the diameter of the inhibition zones against Gram-positive bacteria, gram-negative bacteria, alcohol-acid-resistant and yeast. Antimicrobial activity was considered significant for halos ≥ 15 mm. The results indicate an intensification of antimicrobial action of bark extracts, the 5.0 kGy, against S. aureus. Was held the micro dilution in broth to determine the minimum inhibitory concentration (MIC) and Minimum Bactericidal Concentration (MBC) of peels extracts, compared to eight clinical isolates of S. aureus. The MBC values showed that ionizing radiation did not produce the increased of anti bacteriostatic action of S. terebinthifolius, but the results indicated that S. terebinthifolius bark extracts can be used as an antimicrobial agent and ionizing radiation as an important alternative in this conservation feature.

  19. ESR response to {sup 60}Co-rays of ammonium tartrate pellets using Gd{sub 2}O{sub 3} as additive

    Energy Technology Data Exchange (ETDEWEB)

    Brai, M. [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy) and Unita CNISM, Palermo and Gruppo V Sezione INFN, Catania (Italy)]. E-mail: mbrai@unipa.it; Gennaro, G. [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Marrale, M. [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Unita CNISM, Palermo and Gruppo V Sezione INFN, Catania (Italy); Tranchina, L. [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Bartolotta, A. [Dipartimento Farmacochimico Tossicologico e Biologico, Universita di Palermo, Via Archirafi 32, 90123 Palermo (Italy); Unita CNISM, Palermo and Gruppo V Sezione INFN, Catania (Italy); D' Oca, M.C. [Dipartimento Farmacochimico Tossicologico e Biologico, Universita di Palermo, Via Archirafi 32, 90123 Palermo (Italy)

    2007-02-15

    This work presents experimental results regarding a new ammonium tartrate blend for ESR dosimetry, with a higher sensitivity and a lower lowest detectable dose (LDD) to Co60{gamma}-rays than the recently used pure ammonium tartrate. The blend composed by ammonium tartrate and gadolinium-oxide (Gd{sub 2}O{sub 3}) shows a greater sensitivity ({approx}2 times) and a smaller LDD than ammonium tartrate. The increased sensitivity was mainly attributed to the great atomic number (Z=64) of gadolinium, that increases the effective atomic number of the blend; the interaction probability with photons and consequently the radical yield is therefore enhanced. Moreover ammonium tartrate with Gd{sub 2}O{sub 3} has a linear dose response in the investigated dose range (1-50Gy). We find this blend suitable for use in ESR dosimetry.

  20. Optimisation of radiolysis of Reactive Red 120 dye in aqueous solution using ionising (60)Co gamma radiation by response surface methodology.

    Science.gov (United States)

    Padmanaban, V C; Giri Nandagopal, M S; Achary, Anant; Vasudevan, V N; Selvaraju, N

    2016-01-01

    In recent years, employing radiation technology is gaining great interest in degradation of industrial effluents. In this work the possibility of using gamma irradiation to degrade Reactive Red 120 (C.I.292775) was explored. The effects of pH, dose of gamma irradiation and concentration of dye were examined and their interaction were also established based on their response. For the analysis and optimisation of variables, three factor three level Box-Wilson face centred central composite design (CCF) was used. Analysis of variance with R(2) = 0.9988, adjusted R(2) = 0.9981 and the adequate precision value of 122.303 indicates that the CCF model can be used. The coefficient of variation (0.54%) indicates the reliability of the model. The dose of gamma irradiation (kGy) and the concentration of dye (mg/L) showed significant effects on the degradation of RR 120, while a difference of 6 to 10% degradation was observed in extending the pH towards the acid or alkali range from pH 7.00. The maximum concentration of dye degraded was observed as 347.509 mg/L at initial pH: 7.0, dose of gamma irradiation: 5.94 kGy and initial concentration of dye: 500 mg/L. This predicted value was found to be in agreement with the experimental value on the optimised conditions. PMID:27332851

  1. The regional genomic instability induced by 60Co γ-rays in B16 cells transfected by GFP%60Coγ射线诱导GFP转染的B16细胞区域性基因组不稳定性改变的研究

    Institute of Scientific and Technical Information of China (English)

    刘静; 王亚婷; 林海; 韩倩; 张春晓; 白欧

    2012-01-01

    Objective To detect the regional genomic instability of B16 cells treated with 60Co γ-rays by a green fluorescence protein (GFP)-based genomic instability reporting system.Methods Three groups were employed as non-transfection group,vector control group and transfection group.The GFP-marked reporter construct pCMV-EGFP2XhoI for regional genomic instability was successfully transfected into B16 cells using liposome.B16 cells were selected by screening of G418 with a series of concentrations and limiting dilution cultures to yield a single colony.B16 cells with the genomic instability report system were then irradiated by 60Co γ-rays at doses of 0,2 and 4 Gy.The regional genomic instability of B16 cellswas quantified by counting the number of cells with GFP expression.Results B-16 cell strain steadilyexpressing the GFP-based genomic instability reporting system was established successfully.GFP-positiveB16 cells were observed at 1 d after irradiation with 60Co γ-rays at doses of 2 and 4 Gy.Positive correlations between fluorescence intensity and dose and fluorescence intensity and time were also observed.The positive expression rate of GFP followed the increased of dose (F =36.55,36.76,P < 0.05) and time (t =-3.27,-3.16,-4.26,-6.11,-7.17,P < 0.05),and differences between groups were significant.The positive expression rate of GFP increased significantly at 3 d,and maximum expression was observed at 5 d(2.46 ± 0.24 and 3.82 ± 0.35).The level was tending towards stability.Spontaneous GFP expression at a ratio of 1/600 000 was observed in 0 Gy group after 2 weeks of culture.Conclusions The regional genomic instability of B16 cells induced by 60Co γ-rays can be detected using a GFP-labelled genomic instability reporter system.%目的 应用绿色荧光蛋白(GFP)标记的基因组不稳定性报告系统,检测60Co γ射线诱导B16细胞区域性基因组不稳定性改变.方法 实验分为3组:未转染组、转染组及转染对照组.应用脂质体转染

  2. Cytotoxicity evaluation of Diethyltoluamide (DEET) in Perna perna (Linnaeus, 1758) mussels non-irradiated and irradiated with {sup 60}Co gamma radiation; Avaliacao da citotoxicidade do dietiltoluamida (DEET) em mexilhoes Perna perna (Linnaeus, 1758) irradiados e nao irradiados com radiacao gama de {sup 60}Co

    Energy Technology Data Exchange (ETDEWEB)

    Martini, Gisela de Assis

    2013-07-01

    Recent studies have identified the presence of several emerging pollutants in aquatic environments. The occurrence in different environmental matrices has been continuously reported, highlighting the need for toxicity studies. The DEET (N,N-diethyl-meta-toluamide) is the active ingredient used in most insect repellents, and is present in many commercially available formulations. Apart from chemical pollutants, aquatic organisms are subject to exposure of ionizing radiation from natural sources or in the vicinity of nuclear power plants. The present study evaluated the toxicity of DEET in organisms irradiated and non-irradiated with {sup 60}Co gamma radiation, and the effects that radiation causes in lysosomes of hemocytes of Perna perna mussel. For this purpose, assays were performed to identify the acute toxicity of DEET concentration and the dose of gamma radiation able to cause mortality. Subsequently, cytotoxicity assays were carried out to assess the stability of the lysosomal membrane in organisms exposed to ionizing radiation and DEET. According to the results obtained in acute toxicity tests, the concentration of DEET that causes mortality of 50% exposed organisms (LC50) is 114,27 mg L{sup -1}, and the radiation dose that causes mortality (LD50) is 1068 Gy. In the cytotoxicity assays, the concentration of the non-observed effect (NOEC) for irradiated and non-irradiated organisms 0.0001 mg L-1 and observed effect concentration (LOEC) at concentrations above this. The IC25 (72h) for non-irradiated organisms was 0.0003 mg L-1 and IC50 (72h) was 0.0008 mg L{sup -1} for irradiated and non-irradiated organisms. Despite of the concentrations of effect found in this study were higher than in the environment, both measurements are in the same order of magnitude and should be also take into account the possible synergistic effects of DEET with other contaminants in the aquatic environment. (author)

  3. Gamma ray attenuation in a developed borate glassy system

    Science.gov (United States)

    Saeed, Aly; El shazly, R. M.; Elbashar, Y. H.; Abou El-azm, A. M.; El-Okr, M. M.; Comsan, M. N. H.; Osman, A. M.; Abdal-monem, A. M.; El-Sersy, A. R.

    2014-09-01

    Measurements and calculations of gamma ray attenuation coefficients in glass barriers of xBaO-5ZnO-5MgO-14Na2O--1Li2O-(75-x)B2O3, previously prepared by the melt-quenching technique [1], were performed for γ-ray of energies 121.8, 244.7, 344.14, 661.66, 778.7, 974, 1086.7, 1173.24, 1332.5, and 1407.9 keV; which emitted from 152Eu, 137Cs, and 60Co radioactive gamma ray sources. The transmitted γ-rays were detected by 3″×3″ and 5″×5″ NaI (Tl) scintillation γ-ray spectrometers, and a highly calibrated survey meter. The mass attenuation coefficients of γ-rays (σ(E) were deduced from the attenuation curves, while the WinXCom computer program (version 3.1) was used to calculate the mass attenuation coefficients of γ-rays for such energies at different barium concentrations of a glassy system. A good agreement between both experimental and theoretical results was achieved as well as results obtained by other workers in similar field.

  4. X-Ray Observations of Gamma-Ray Burst Afterglows

    OpenAIRE

    Frontera, Filippo

    2004-01-01

    The discovery by the BeppoSAX satellite of X-ray afterglow emission from the gamma-ray burst which occurred on 28 February 1997 produced a revolution in our knowledge of the gamma-ray burst phenomenon. Along with the discovery of X-ray afterglows, the optical afterglows of gamma-ray bursts were discovered and the distance issue was settled, at least for long $\\gamma$-ray bursts. The 30 year mystery of the gamma-ray burst phenomenon is now on the way to solution. Here I rewiew the observationa...

  5. Cascaded Gamma Rays as a Probe of Cosmic Rays

    Science.gov (United States)

    Murase, Kohta

    2014-06-01

    Very-high-energy (VHE) and ultra-high-energy (UHE) gamma rays from extragalactic sources experience electromagnetic cascades during their propagation in intergalactic space. Recent gamma-ray data on TeV blazars and the diffuse gamma-ray background may have hints of the cascade emission, which are especially interesting if it comes from UHE cosmic rays. I show that cosmic-ray-induced cascades can be discriminated from gamma-ray-induced cascades with detailed gamma-ray spectra. I also discuss roles of structured magnetic fields, which suppress inverse-Compton pair halos/echoes but lead to guaranteed signals - synchrotron pair halos/echoes.

  6. The combined effect of the gamma radiations of 60 Co and different chemicals on the cells of the radicular vegetative tip of Allium sativum L

    International Nuclear Information System (INIS)

    The gamma ionizing radiations used alone in the treatment of Allium Sativum L. affected differently the cells belonging to the two zones of the root causing modifications of the cellular parameters which have been previously estimated. Data in the literature established that the damage of the interphasic nucleus of the cells determines the obstruction of the DNA synthesis and the delay of the cell mitosis. Sparrow, A. H., Miller, M. W. and Al-Rubeai confirmed the existence of a relationship between the nuclear volumes and the radiosensitivity of the different types of cells. The aim of this experiment was to counteract the harmful effect of gamma radiations at cellular level with the help of combined treatments, namely, the gamma radiations associated with different chemicals having radioprotective effects. The biological significance of the obtained values was established by statistical calculations with the help of the Student (t) test. The values of the estimated cellular parameters, NV, ICV, CV, NCR showed that, although there were certain fluctuations, their values were not always significant. (author)

  7. Effects of {gamma} ({sup 60}Co) and {beta} ({sup 90}Sr) radiations in Chinese hamster ovarian cells (CHO-K1): induction of micronuclei and cell death; Efeitos das radiacoes {gamma} ({sup 60}Co) e {beta} ({sup 90}Sr) em celulas de ovario de hamster chines (CHO-K1): inducao de micronucleos e morte celular

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Daniella

    2003-07-01

    Among various types of ionising radiation, the beta emitter radionuclides are involved in many sectors of human activity, such as nuclear medicine, nuclear industries and biomedicine, with a consequent increased risk of accidental, occupational or therapeutic exposure. Despite their recognized importance, there is little information about the effect of beta particles at the cellular level when compared to other types of ionizing radiation. Thus, the objective of the present study was to evaluate the genotoxic and cytotoxic effects of {sup 90}Sr, a pure, highly energetic beta source, on CHO-K1 cells and to compare them with data obtained with {sup 60}Co. CHO-K1 cells irradiated with different doses (1.0, 2.5, 5.0, 7.5 Gy) of {sup 60}Co (0.34 Gy.min{sup -1}) and {sup 90}Sr (0.23 Gy.min{sup -1}) were processed for analysis of clonogenic death, induction of micronuclei (MN) and necrotic and apoptotic death. The survival curves obtained for both types of radiation were better fitted by the linear-quadratic model and were similar. However, the cytogenetic results showed that both the proportion of micronucleated cells and the magnitude of radioinduced lesions demonstrated by the analysis of MN distribution were significantly higher in cells irradiated with {sup 60}Co than in cells irradiated with {sup 90}Sr, whereas {sup 90}Sr was more damaging than {sup 60}Co in terms of cell death induction. Necrosis was the major type of death observed in CHO-K1 cells. The data obtained suggest that the low incidence of micronucleated cells after exposure to {sup 90}Sr may be a consequence of selective elimination of severely damaged cells from the population by the necrotic process at a higher rate than observed with {sup 60}Co exposure. The data obtained also demonstrated the need to use several parameters for a better estimate of cellular sensitivity to the action of genotoxic agents, which would be important in terms of radiobiology, oncology and therapeutics. (author)

  8. 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

  9. Gamma-ray performance of the GAMMA-400 detector

    CERN Document Server

    Cumani, P; Bonvicini, V; Topchiev, N P; Adriani, O; Aptekar, R L; Arkhangelskaja, I V; Arkhangelskiy, A I; Bergstrom, L; Berti, E; Bigongiari, G; Bobkov, S G; Boezio, M; Bogomolov, E A; Bonechi, S; Bongi, M; Bottai, S; Castellini, G; Cattaneo, P W; Dedenko, G L; De Donato, C; Dogiel, V A; 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; Menshenin, A L; Mikhailov, V V; Mocchiutti, E; Moiseev, A A; Mori, N; Moskalenko, I V; Naumov, P Yu; Papini, P; Pearce, M; Picozza, P; Popov, A V; Rappoldi, A; Ricciarini, S; Runtso, M F; Ryde, F; Sarkar, R; Serdin, O V; Sparvoli, R; Spillantini, P; Suchkov, S I; Tavani, M; Taraskin, A A; Tiberio, A; Tyurin, E M; Ulanov, M V; Vacchi, A; Vannuccini, E; Vasilyev, G I; Yurkin, Yu T; Zampa, N; Zirakashvili, V N; Zverev, V G

    2015-01-01

    GAMMA-400 is a new space mission, designed as a dual experiment, capable to study both high energy gamma rays (from $\\sim$100 MeV to few TeV) and cosmic rays (electrons up to 20 TeV and nuclei up to $\\sim$10$^{15}$ eV). The full simulation framework of GAMMA-400 is based on the Geant4 toolkit. The details of the gamma-ray reconstruction pipeline in the three main instruments (Tracker, Imaging Calorimeter, Homogeneous Calorimeter) will be outlined. The performance of GAMMA-400 (PSF, effective area and sensitivity) have been obtained using this framework. The most updated results on them will be shown.

  10. Measurements of high-energy {gamma}-rays with LaBr{sub 3}:Ce detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ciemala, M. [Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, 31-342 Krakow (Poland)], E-mail: Michal.Ciemala@ifj.edu.pl; Balabanski, D. [INRNE, Bulgarian Academy of Sciences, BG-1784 Sofia (Bulgaria); Csatlos, M. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), P.O. Box 51, H-4001 Debrecen (Hungary); Daugas, J.M. [CEA, DAM, DIF, F-91297 Arpajon Cedex (France); Georgiev, G. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM), IN2P3-CNRS and Universite Paris-Sud, Bat 104-108, F-91405 Orsay Cedex (France); Gulyas, J. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), P.O. Box 51, H-4001 Debrecen (Hungary); Kmiecik, M. [Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, 31-342 Krakow (Poland); Krasznahorkay, A. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), P.O. Box 51, H-4001 Debrecen (Hungary); Lalkovski, S. [Faculty of Physics, University of Sofia, BG-1164 (Bulgaria); Lefebvre-Schuhl, A. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM), IN2P3-CNRS and Universite Paris-Sud, Bat 104-108, F-91405 Orsay Cedex (France); Lozeva, R. [Instituut voor Kernen Stralingsfysica (IKS), Katholieke Universiteit Leuven, B-3001 Leuven (Belgium); Maj, A. [Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, 31-342 Krakow (Poland); Vitez, A. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), P.O. Box 51, H-4001 Debrecen (Hungary)

    2009-09-01

    The full-energy peak efficiency calibration and the energy resolution measurements of the 2in.x2in.LaBr{sub 3}{gamma}-ray detector are presented for {gamma}-ray energies in the 700 keV-17.6 MeV range. Measurements were done using a combination of proton-capture nuclear reactions on {sup 27}Al, {sup 23}Na, {sup 39}K, {sup 7}Li and {sup 11}B for high-energy {gamma}-rays, and radioactive sources such as {sup 60}Co and {sup 152}Eu for the lowest energies. At high energies, two {gamma}-rays in a cascade from proton resonance capture were employed using Al, Na{sub 2}WO{sub 4}, K{sub 2}SO{sub 4} and LiBO{sub 2} targets. The obtained results were compared to the simulations performed using a GEANT4 code.

  11. 五指毛桃水提液对60Coγ射线致小鼠骨髓细胞DNA损伤的防护作用%Protective Role of Aqueous Extract from Fici Hirtae Radix for DNA Damage of Bone Marrow Cells by 60Coγ-Ray in Mice

    Institute of Scientific and Technical Information of China (English)

    王晓平; 段丽菊; 黄翔; 岑业文; 李桂芬

    2011-01-01

    目的 探讨五指毛桃水提液对60Coγ射线所致的小鼠骨髓细胞DNA损伤的防护作用.方法 40只SPF级♂小鼠随机分为5组:阴性对照组给予生理盐水,辐射模型组单纯接受照射,3个五指毛桃剂量组分别给予相当于生药5,10,20 g.kg-1.d-1五指毛桃水提液,连续灌胃7d.除阴性对照组外,所有小鼠接受全身一次性60Coγ射线照射,照射剂量为6Gy.照射24 h后处死小鼠,取股骨,制作骨髓单细胞悬液,用单细胞凝胶电泳实验检测小鼠骨髓细胞DNA损伤情况.结果 辐射模型组小鼠骨髓细胞DNA的尾部DNA百分率(Tail DNA%)和尾矩(Tail Moment)高于阴性对照组(P<0.01),五指毛桃各剂量组的 Tail DNA%和Tail Moment均显著低于辐射模型组(P<0.01),且随着给药剂量的增加,Tail DNA%和Tail Moment降低.结论 五指毛桃水提液对60Coγ射线损伤小鼠骨髓细胞DNA具有一定的防护作用.%OBJECTIVE To investigate the protective role of aqueous extract from Fici Hirtae Radix for bone marrow cells DNA of 60Coγ-ray irradiated mice. METHODS Forty SPF male mice were randomized into 5 groups. Negative control group was given normal saline, irradiated group was radiation model group and 3 Fici Hirtae Radix dose groups were orally given aqueous extracts from Fici Hirtae Radix of 5, 10, 20 g·kg-1·d-1 for 7 consecutive days. Except the negative control group, all mice received 6 Gy irradiation of whole body. After 24 h of irradiation, mice were sacrificed on femur. Single cell suspension was produced. DNA damage was detected using single cell gel electrophoresis experiment. RESULTS The results showed that Tail DNA% and Tail Moment of radiation model mice were higher than negative control group (P<0.01). Tail DNA% and Tail Moment of all Fici Hirtae Radix dose groups were significantly lower than radiation model group(P<0.01). As the dose increased,Tail DNA% and Tail Moment reduced. CONCLUSION Aqueous extracts from Fici Hirtae Radix have

  12. The influence of {sup 60}Co gamma radiation on the action of phenolic compounds Anadenanthera colubrina (Vell.) Brenan in the microbiological control of crude extracts

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Gustavo Henrique F. dos; Silva, Edvane B. da, E-mail: santosghf@hotmail.co [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia (GERAR); Sena, Kesia Xisto da Fonseca R. de; Silva, Bruna L., E-mail: kxfrs@bol.com.b [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Antibioticos; Lima, Claudia S. de A., E-mail: claudia.salima@gmail.co [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Biofisica e Radiobiologia

    2009-07-01

    Anadenanthera colubrina (Vell.) Brenan, known popularly as angico is a tree founded in northeastern of Brazil, and has great economic and ecological interest. These trees are characterized by high levels of tannins. To evaluate the influence of gamma radiation in plant extracts of barks and leaves of angico, we got extracts of barks and leaves in 70% ethanol, which was filtered and evaporated until dryness. It were classified in four groups (non-irradiated, 5; 7.5 and 10 kGy). The total phenols were quantified by Folin-Ciocalteau method, and the tannins, using the precipitation of casein. The antimicrobial activity of extracts was observed using the paper disk diffusion methods against Gram-positive, Gram-negative, acid-alcohol-resistant bacteria: and yeasts. The halos greater than 10 mm were considered actives. It was also performed the Minimal Inhibitory Concentration (MIC) using Gram positive and alcohol-acid resistant bacteria. The results showed that tannins of A. colubrina, were 52 to 57% of total phenols, and leaves, 58 to 60%. The percentage of total phenols and tannins in the barks and leaves of A. colubrina have not statistically significant change when compared with the irradiated control. These results suggest that A. colubrina has antimicrobial activity against the Gram-positive and alcohol-acid -resistant bacteria, confirmed by MIC. The extracts of leaves it was additionally actives against the Gram-negative and against the yeast C. albicans. These results show that the gamma radiation has not influence about the antimicrobial activity of crude extracts of barks and leaves of A. colubrina. (author)

  13. The influence of 60Co gamma radiation on the action of phenolic compounds Anadenanthera colubrina (Vell.) Brenan in the microbiological control of crude extracts

    International Nuclear Information System (INIS)

    Anadenanthera colubrina (Vell.) Brenan, known popularly as angico is a tree founded in northeastern of Brazil, and has great economic and ecological interest. These trees are characterized by high levels of tannins. To evaluate the influence of gamma radiation in plant extracts of barks and leaves of angico, we got extracts of barks and leaves in 70% ethanol, which was filtered and evaporated until dryness. It were classified in four groups (non-irradiated, 5; 7.5 and 10 kGy). The total phenols were quantified by Folin-Ciocalteau method, and the tannins, using the precipitation of casein. The antimicrobial activity of extracts was observed using the paper disk diffusion methods against Gram-positive, Gram-negative, acid-alcohol-resistant bacteria: and yeasts. The halos greater than 10 mm were considered actives. It was also performed the Minimal Inhibitory Concentration (MIC) using Gram positive and alcohol-acid resistant bacteria. The results showed that tannins of A. colubrina, were 52 to 57% of total phenols, and leaves, 58 to 60%. The percentage of total phenols and tannins in the barks and leaves of A. colubrina have not statistically significant change when compared with the irradiated control. These results suggest that A. colubrina has antimicrobial activity against the Gram-positive and alcohol-acid -resistant bacteria, confirmed by MIC. The extracts of leaves it was additionally actives against the Gram-negative and against the yeast C. albicans. These results show that the gamma radiation has not influence about the antimicrobial activity of crude extracts of barks and leaves of A. colubrina. (author)

  14. Application of Induced Mutation by Using Gamma Ray Treatment in Study Breeding for Orchid (Phalaenopsis) Varieties

    International Nuclear Information System (INIS)

    Aim to breed new orchid varieties adapted to climate of Vietnam for domestic use and export, national orchid breeding program has been established for some years. In our study, application of induced mutation by using 60Co. gamma ray treatment was set up to breed new varieties of Phalaenopsis orchid. Different dosages of 60Co. gamma rays were 0, 20, 40, 60, 100 Gy doses with dose rate of 90 Gy/h. Three years after radiation treatment, result showed that the use of 60Co. gamma rays for treatment had conspicuously influenced to growth, mutation frequencies in morphological and physiological traits of Phalaenopsis varieties. Survival rate and growth vigor of treated plants reduced while total variation ratio increased by higher doses. The useful variations were the highest in 20 Gy and next to 40 Gy radiation treatments. In this study, LD50 dose in radiation treatment for Phalaenopsis orchid variety was at dose 40 Gy. Suitable doses in radiation treatment which made wide diversity for Phalaenopsis orchid was at doses 20-40 Gy. At present, selected Phalaenopsis lines are being conducted to research segregating mutated traits, mutation frequencies in inbred Phalaenopsis lines and multiplication of promising mutant lines. (author)

  15. Gamma-Ray Interactions for Reachback Analysts

    Energy Technology Data Exchange (ETDEWEB)

    Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Myers, Steven Charles [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-02

    This presentation is a part of the DHS LSS spectroscopy training course and presents an overview of the following concepts: identification and measurement of gamma rays; use of gamma counts and energies in research. Understanding the basic physics of how gamma rays interact with matter can clarify how certain features in a spectrum were produced.

  16. Effects of {sup 60}Co gamma radiation on toxicity and hemorrhagic, myonecrotic, and edema-forming activities of Cerastes cerastes venom

    Energy Technology Data Exchange (ETDEWEB)

    Abib, H. [Univ. des Sciences et de la Technologie, Lab. de Biologie Cellulaire et Moleculaire, Faculte des Sciences Biologiques, Houari Boumedienne, Bab Ezzouar (Algeria); Laraba-Djebari, F. [Inst. Pasteur d' Algerie, Lab. de Recherche et de Developpement sur les Venins, Alger (Algeria)]. E-mail: flaraba@ibnsina.ands.dz

    2003-12-01

    Antisera are used as effective antidotes against the local effects of snake bites. To improve antisera production and extend the life of surrogates used to produce antibodies, the chronic effects of venom toxicity must be reduced. The present study evaluated the effectiveness of gamma irradiation to reduce the local effects associated with viperid snake bites by evaluating in NMRI mice the toxicity and edematic, hemorrhagic, and myonecrotic activities of native and irradiated Cerastes cerastes venoms. These results indicated that the toxicity of irradiated venoms (1 and 2 kGy) decreased as compared with that of native venom. The edematic and hemorrhagic activities were also reduced in the detoxified samples, particularly with the 2-kGy radiation dose. Furthermore, the creatine phosphokinase (CPK) activity was significantly increased in the serum and decreased in the myocardium after envenomation with native venom, but no significant enzymatic changes were observed in mice envenomated with irradiated venom. Histopathologic evaluation showed that native venom caused severe degenerative changes in the myocardium. In the case of 2-kGy-irradiated venom, no tissue alterations were observed. These results indicate that irradiation of venom with a 2-kGy dose may offer an effective method for reducing the chronic toxic effects of venom in immunized animals. (author)

  17. Study of the effect of gamma irradiation (60 Co) on the quality of sugar cane spirit and on the cask of maturation

    International Nuclear Information System (INIS)

    The ageing or maturing process of drink improves the sensorial characteristics of the product making it a qualified drink with higher economical value. The traditional maturing method of drinks involves their interaction with wood and irradiation can accelerate this ageing process. Sugar cane spirit and oak barrels with a 20 L capacity were treated using gamma irradiation (150 Gy). Physical-chemical and chromatographic analyses were constantly performed for 390 days during the drink ageing period. The sugar cane spirit and barrel irradiation did not change most volatile components of the same type coefficient such as volatile acidity, esters, superior alcohols and furfural throughout the 390 days. There is evidence, however, that some component parameters like aldehydes, tannin, color and copper concentration are in some way influenced resulting in partial acceleration of the ageing or maturing process. At the end of the ageing period, a sensorial analysis was made using 30 non-trained people who tasted the drink. The ageing process acceleration was confirmed by the sensorial evaluation, where the irradiated sugar cane spirit and/or barrel had higher approval regarding all parameters analyzed (scent, flavor and appearance). (author)

  18. Study of the effect of gamma irradiation (60CO) on the quality of sugar cane spirit and on the cask of maturation

    International Nuclear Information System (INIS)

    The ageing or maturing process of drink improves the sensorial characteristics of the product making it a qualified drink with higher economical value. The traditional maturing method of drinks involves their interaction with wood and irradiation can accelerate this ageing process. Sugar cane spirit and oak barrels with a 20 L capacity were treated using gamma irradiation (150 Gy). Physical-chemical and chromatographic analyses were constantly performed for 390 days during the drink ageing period. The sugar cane spirit and barrel irradiation did not change most volatile components of the same type coefficient such as volatile acidity, esters, superior alcohols and furfural throughout the 390 days. There is evidence, however, that some component parameters like aldehydes, tannin, color and copper concentration are in some way influenced resulting in partial acceleration of the ageing or maturing process. At the end of the ageing period, a sensorial analysis was made using 30 non-trained people who tasted the drink. The ageing process acceleration was confirmed by the sensorial evaluation, where the irradiated sugar cane spirit and/or barrel had higher approval regarding all parameters analyzed (scent, flavor and appearance)

  19. Effect of dose-rate of gamma irradiation (60Co) on the anti nutritional compounds phytic acid and antitrypsin on soybean (glycine max L.)

    International Nuclear Information System (INIS)

    An investigation on the effect of gamma irradiation at different dose-rate on the anti-nutritional compounds (phytic acid and antitrypsin) and the color of soybean has been conducted. The purpose of the study was to analyze the influence of the dose-rate on the rate of change of anti-nutritional compounds and color. Samples were irradiated with dose-rates of 1.30; 3.17; 5.71 and 8.82 kGy/hour with irradiation time varied from 0.5 to 55 hours. Phytic acid content and antitrypsin activity, as well as their L α b color values were analyzed. Results showed that a simple first order kinetics model can be used to describe changes in the concentration of the anti-nutritional compounds and color soybeans during the radiation processing. Data indicate that irradiation process at higher dose-rate (shorter time) is more effective in destroying anti-nutritional compounds as compared to that of irradiation process at lower dose-rate (longer time). Furthermore, irradiation process at higher dose-rate (shorter time) also have less detrimental effect on color of the soybean and the resulted soybean flour as compared to that of irradiation process at lower dose-rate (longer time). These findings suggest that irradiation process at a same dose may potentially be optimized by selecting the most appropriate combination of dose-rate and time of irradiation. (author)

  20. Effect of {sup 60}Co gamma radiation on the levels of phenolic compounds from crude extracts of bark of Spondias luta L

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Gustavo H.F.; Silva, Hianna A.M.F.; Melo, Mychely S., E-mail: santosghf@hotmail.com, E-mail: hiannaamfs@gmail.com, E-mail: mychely.melo@gmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Silva, Edvane B., E-mail: edvborges@yahoo.com [Universidade Federal de Pernambuco (UFPE), Vitoria de Santo Antao, PE (Brazil). Centro Academinco de Vitoria

    2013-07-01

    Spondias luta L. (Anacardiaceae), popularly known as cajazeira, is a plant widespread in several regions of Brazil, famous for containing phenolic compounds, which are responsible for your characteristic astringent. Ionizing radiations have the ability to cross the material, ionizing atoms and molecules, causing changes in atoms and molecules important. It is known ionizing radiation promotes quantitative and qualitative changes in plant materials, increasing, decreasing or inactivating secondary substances. The objective of this work was to evaluate the effect of gamma radiation as a modifier of the activity of the phenolic compounds of the bark extract of S. luta L. Methods: For the dosage of phenol extracts (control, irradiated with 5 kGy, 10 kGy, 15 kGy and 20 kGy) were diluted in methanol to a final concentration of 200 mg / L. In test tubes were added 50 μL of extract plus 1 ml of distilled water and 500 μl of Folin (diluted 1:10). After 10 minutes in a dark chamber was added 2.5 ml of calcium carbonate to 20% and the content of the tube was homogenized. After 20 minutes was performed with a spectrophotometer at 735 nm. The assay was performed in triplicate and calculated from a standard curve solution of gallic acid and expressed in μEAG (GAE/mg extract). Results: The control extracts, irradiated to 5 kGy, 10 kGy, 15 kGy and 20 kGy, had, respectively, 6.25, 6.70, 6.25, 6.85, 6.45 μEAG/mg of extract. Conclusion: The results showed no significant change in the amount of phenolic compounds, showing that these compounds are radioresistant extract these doses. (author)

  1. 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, ΔE, 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)

  2. Gamma-Ray Interactions for Reachback Analysts

    Energy Technology Data Exchange (ETDEWEB)

    Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Myers, Steven Charles [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-02

    This presentation is a part of the DHS LSS spectroscopy training course and presents an overview of the following concepts: identification and measurement of gamma rays; use of gamma counts and energies in research.

  3. X-Ray and Gamma-Ray Radiation Detector

    DEFF Research Database (Denmark)

    2015-01-01

    Disclosed is a semiconductor radiation detector for detecting X-ray and / or gamma-ray radiation. The detector comprises a converter element for converting incident X-ray and gamma-ray photons into electron-hole pairs, at least one cathode, a plurality of detector electrodes arranged with a pitch...

  4. Gravitational microlensing of gamma-ray blazars

    DEFF Research Database (Denmark)

    F. Torres, Diego; E. Romero, Gustavo; F. Eiroa, Ernesto;

    2003-01-01

    We present a detailed study of the effects of gravitational microlensing on compact and distant $\\gamma$-ray blazars. These objects have $\\gamma$-ray emitting regions which are small enough as to be affected by microlensing effects produced by stars lying in intermediate galaxies. We analyze...... the temporal evolution of the gamma-ray magnification for sources moving in a caustic pattern field, where the combined effects of thousands of stars are taken into account using a numerical technique. We propose that some of the unidentified $\\gamma$-ray sources (particularly some of those lying at high...... galactic latitude whose gamma-ray statistical properties are very similar to detected $\\gamma$-ray blazars) are indeed the result of gravitational lensing magnification of background undetected Active Galactic Nuclei (AGNs)....

  5. Understanding Doppler Broadening of Gamma Rays

    Energy Technology Data Exchange (ETDEWEB)

    Rawool-Sullivan, Mohini [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sullivan, John P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-07-03

    Doppler-broadened gamma ray peaks are observed routinely in the collection and analysis of gamma-ray spectra. If not recognized and understood, the appearance of Doppler broadening can complicate the interpretation of a spectrum and the correct identification of the gamma ray-emitting material. We have conducted a study using a simulation code to demonstrate how Doppler broadening arises and provide a real-world example in which Doppler broadening is found. This report describes that study and its results.

  6. 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

  7. Radiobiological studies using gamma and x rays.

    Energy Technology Data Exchange (ETDEWEB)

    Potter, Charles Augustus; Longley, Susan W.; Scott, Bobby R.; Lin, Yong; Wilder, Julie; Hutt, Julie A.; Padilla, Mabel T.; Gott, Katherine M.

    2013-02-01

    There are approximately 500 self-shielded research irradiators used in various facilities throughout the U.S. These facilities use radioactive sources containing either 137Cs or 60Co for a variety of biological investigations. A report from the National Academy of Sciences[1] described the issues with security of particular radiation sources and the desire for their replacement. The participants in this effort prepared two peer-reviewed publications to document the results of radiobiological studies performed using photons from 320-kV x rays and 137Cs on cell cultures and mice. The effectiveness of X rays was shown to vary with cell type.

  8. Gamma ray attenuation in a developed borate glassy system

    International Nuclear Information System (INIS)

    Measurements and calculations of gamma ray attenuation coefficients in glass barriers of xBaO–5ZnO–5MgO–14Na2O–-1Li2O–(75−x)B2O3, previously prepared by the melt-quenching technique [1], were performed for γ-ray of energies 121.8, 244.7, 344.14, 661.66, 778.7, 974, 1086.7, 1173.24, 1332.5, and 1407.9 keV; which emitted from 152Eu, 137Cs, and 60Co radioactive gamma ray sources. The transmitted γ-rays were detected by 3″×3″ and 5″×5″ NaI (Tl) scintillation γ-ray spectrometers, and a highly calibrated survey meter. The mass attenuation coefficients of γ-rays (σ(E)) were deduced from the attenuation curves, while the WinXCom computer program (version 3.1) was used to calculate the mass attenuation coefficients of γ-rays for such energies at different barium concentrations of a glassy system. A good agreement between both experimental and theoretical results was achieved as well as results obtained by other workers in similar field. - Highlights: • Design new glass system can be used as nuclear radiation shielding material. • Three different systems were used to measure γ-ray attenuation coefficients. • The γ-ray attenuation coefficients in this glass system were measured for 10 γ-energy lines. • Good agreement between experimental, theoretical, and results by other workers have been achieved. • Improvement of σ and HVL by increasing BaO concentration up to 50% in our glassy system

  9. Test experiment of gamma-ray diffraction using silicon crystal

    International Nuclear Information System (INIS)

    A γ-ray diffraction property of a silicon single crystal and collimator system were studied in the Laue geometry using 1.33 MeV and 1.17 MeV γ-ray of 60Co. The thickness was chosen to maximize the reflectivity of (440) lattice plane in γ-ray energy of 1.5 MeV. We measured diffracted γ-rays from the crystal by an NaI scintillator. A measured diffraction intensity of 1.33 MeV γ-rays was 37 counts/sec by using 3.0 TBq a 60Co γ-ray radiation system. (author)

  10. Modeling gamma-ray bursts

    Science.gov (United States)

    Maxham, Amanda

    Discovered serendipitously in the late 1960s, gamma-ray bursts (GRBs) are huge explosions of energy that happen at cosmological distances. They provide a grand physical playground to those who study them, from relativistic effects such as beaming, jets, shocks and blastwaves to radiation mechanisms such as synchrotron radiation to galatic and stellar populations and history. Through the Swift and Fermi space telescopes dedicated to observing GRBs over a wide range of energies (from keV to GeV), combined with accurate pinpointing that allows ground based follow-up observations in the optical, infrared and radio, a rich tapestry of GRB observations has emerged. The general picture is of a mysterious central engine (CE) probably composed of a black hole or neutron star that ejects relativistic shells of matter into intense magnetic fields. These shells collide and combine, releasing energy in "internal shocks" accounting for the prompt emission and flaring we see and the "external shock" or plowing of the first blastwave into the ambient surrounding medium has well-explained the afterglow radiation. We have developed a shell model code to address the question of how X-ray flares are produced within the framework of the internal shock model. The shell model creates randomized GRB explosions from a central engine with multiple shells and follows those shells as they collide, merge and spread, producing prompt emission and X-ray flares. We have also included a blastwave model, which can constrain X-ray flares and explain the origin of high energy (GeV) emission seen by the Fermi telescope. Evidence suggests that gamma-ray prompt emission and X-ray flares share a common origin and that at least some flares can only be explained by long-lasting central engine activity. We pay special attention to the time history of central engine activity, internal shocks, and observed flares. We calculate the gamma-ray (Swift/BAT band) and X-ray (Swift/XRT band) lightcurves for arbitrary

  11. 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.

  12. Gamma-ray emission from thunderstorm discharges

    International Nuclear Information System (INIS)

    Fine features of gamma-ray radiation registered during a thunderstorm at Tien-Shan Mountain Cosmic Ray Station are presented. Long duration (100-600 ms) gamma-ray bursts are found. They are for the first time identified with atmospheric discharges (lighting). Gamma-ray emission lasts all the time of the discharge and is extremely non-uniform consisting of numerous flashes. Its peak intensity in the flashes exceeds the gamma-ray background up to two orders of magnitude. Exclusively strong altitude dependence of gamma radiation is found. The observation of gamma radiation at the height 4-8 km could serve as a new important method of atmospheric discharge processes investigation. - Highlights: → Gamma-radiation bursts always accompany the electric discharges in atmosphere. → The gamma burst fill up the time of an atmospheric discharge completely. → The higher is the discharge electric field change - the higher is gamma intensity. → The temporal distribution of gamma intensity during the burst is non-uniform. → The altitude dependence of the burst gamma intensity is dramatic.

  13. 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 γ-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)

  14. Dose Rate and Mass Attenuation Coefficients of Gamma Ray for Concretes

    International Nuclear Information System (INIS)

    This work is concerned with the study of the leakage gamma ray dose and mass attenuation coefficients for ordinary, basalt and dolomite concretes made from local ores. Concretes under investigation were constructed from gravel, basalt and dolomite ores, and then reconstructed with the addition of 3% steel fibers by weight. Measurements were carried out using a collimated beam from 60Co gamma ray source and sodium iodide (3x3) crystal with the genie 2000 gamma spectrometer. The obtained fluxes were transformed to gamma ray doses and displayed in the form of gamma ray dose rates distribution. The displayed curves were used to estimate the linear attenuation coefficients (mu), the relaxation lengths (lambda), half value layer (t1/2) and tenth value layer (t1/10). Also, The total mass attenuation coefficients of gamma ray have been calculated to the concerned concretes using XCOM (version 3.1) program and database elements cross sections from Z=1 to 100 at energies from 10 keV to 100 MeV. In addition, the total mass attenuation coefficients of gamma rays have been evaluated based on the measured data and compared with those the calculated results. A comparison between measured and calculated show a reasonable agreement between them

  15. 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.

  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. Handbook on Mobile Gamma-ray Spectrometry

    DEFF Research Database (Denmark)

    Aage, Helle Karina; Korsbech, Uffe C C

    2003-01-01

    Basic physics and mathematics for Airborne and Car-borne Gamma-ray Spectrometry supplemented with practical examples and methods for advanced data processing......Basic physics and mathematics for Airborne and Car-borne Gamma-ray Spectrometry supplemented with practical examples and methods for advanced data processing...

  18. Sensitivity of P-Channel MOSFET to X- and Gamma-Ray Irradiation

    Directory of Open Access Journals (Sweden)

    Milić Pejović

    2013-01-01

    Full Text Available Investigation of Al-gate p-channel MOSFETs sensitivity following irradiation using 200 and 280 kV X-ray beams as well as gamma-ray irradiation of 60Co in the dose range from 1 to 5 Gy was performed in this paper. The response followed on the basis of threshold voltage shift and was studied as a function of absorbed dose. It was shown that the most significant change in threshold voltage was in the case of MOSFET irradiation in X-ray fields of 200 kV and when the gate voltage was +5 V. For practical applications in dosimetry, the sensitivity of the investigated MOSFETs was also satisfactory for X-ray tube voltage of 280 kV and for gamma rays. Possible processes in gate oxide caused by radiation and its impact on the response of MOSFETs were also analyzed in this paper.

  19. Effect of Gamma Rays on Fast Neutron Registration in CR-39

    CERN Document Server

    Kobzev, A P; El-Halem, A A; Abdul-Ghaphar, U S; Salama, T A

    2002-01-01

    A set of CR-39 plastic detectors with front PE radiator was exposed to Am-Be neutron source, which has an emission rate of 0.86\\cdot 10^{7} sec^{-1}, and the neutron dose equivalent rate 1 m apart from the source is equal to 11 mrem/hr. Another set of samples was irradiated by a neutron dose of 4 rem, then exposed to different gamma-ray doses using ^{60}Co source. It was found that the track density grows with the increase of neutron dose and etching time. It was also found that the bulk etching rate V_{B}, the track diameter and the sensitivity of the CR-39 plastic detector with respect to the neutron irradiation increased with increasing gamma-ray dose in the range 1?10 Mrad. These results show that CR-39 can be considered as a promising fast neutron dosimeter and gamma-ray dosimeter.

  20. Effect of gamma-ray radiation on the polyacrylonitrile based carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Xu Zhiwei, E-mail: xuzhiwei@tjpu.edu.c [Key Laboratory of Advanced Braided Composites, Ministry of Education, Composite Research Institute, Chenglin Road, Tianjin Polytechnic University, Tianjin 300160 (China); Huang Yudong [School of Chemical Engineering and Technology, Harbin Institute of Technology, P.O. Box 410, Harbin 150001 (China); Min Chunying [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Chen Lei; Chen Li [Key Laboratory of Advanced Braided Composites, Ministry of Education, Composite Research Institute, Chenglin Road, Tianjin Polytechnic University, Tianjin 300160 (China)

    2010-08-15

    To investigate the effect of gamma-ray radiation on the microstructural and mechanical properties of carbon fibers, carbon fibers were irradiated by {sup 60}Co source. The interlayer spacing d{sub 002} of carbon fibers decreased after irradiation. The Young's modulus and density of the fibers increased with increasing dose. The tensile strength of fibers was found to increase at low dose and decrease at high dose. Additionally, Compton scattering effect caused by gamma-ray is proposed to be responsible for the structural and mechanical changes of fibers. The results indicated that gamma-ray irradiation was an effective method for improving the mechanical properties and graphitization degree of polyacrylonitrile based carbon fibers.

  1. A method to determine the gamma-ray linear attenuation coefficient

    International Nuclear Information System (INIS)

    Highlights: → Gamma-ray linear attenuation coefficients of some absorber materials was examined. → Traditional energy method and timing detection technique were used. → Timing method was successful in determination of the linear attenuation coefficient. - Abstract: In this work, gamma-ray linear attenuation coefficients of the materials such as Pb, Fe, Cu and Al were determined by means of traditional energy method and the developed timing detection technique. 1.33 MeV-energy radiation emitted from 60Co radioisotope was used in the experiments. The gamma-ray linear attenuation coefficient values of the materials were calculated by using Xcom code, and the experimental results were compared with the theoretical ones.

  2. Gamma-ray pulsars: a gold mine

    CERN Document Server

    Grenier, Isabelle A

    2015-01-01

    The most energetic neutron stars, powered by their rotation, are capable of producing pulsed radiation from the radio up to gamma rays with nearly TeV energies. These pulsars are part of the universe of energetic and powerful particle accelerators, using their uniquely fast rotation and formidable magnetic fields to accelerate particles to ultra-relativistic speed. The extreme properties of these stars provide an excellent testing ground, beyond Earth experience, for nuclear, gravitational, and quantum-electrodynamical physics. A wealth of gamma-ray pulsars has recently been discovered with the Fermi Gamma-Ray Space Telescope. The energetic gamma rays enable us to probe the magnetospheres of neutron stars and particle acceleration in this exotic environment. We review the latest developments in this field, beginning with a brief overview of the properties and mysteries of rotation-powered pulsars, and then discussing gamma-ray observations and magnetospheric models in more detail.

  3. Gamma-ray detected radio galaxies

    Science.gov (United States)

    Beckmann, Volker; Soldi, Simona; De Jong, Sandra; Kretschmer, Karsten; Savchenko, Volodymyr

    2016-07-01

    So far 15 radio galaxies have been detected in the gamma-ray domain by CGRO/EGRET and Fermi/LAT, with a few detections also in the VHE range. We search for distinguishing parameters and estimate the total number of gamma-ray emitting radio galaxies that are potentially detectable by Fermi/LAT. We use Fermi/LAT data in comparison with X-ray and hard X-ray data in order to constrain basic parameters such as the total power of the inverse Compton branch and the position of its peak. We search for possible correlations between the radio, UV, X-ray, and gamma-ray domain and derive the number counts distribution. We then compare their properties with those of the radio galaxies in the 3CRR and SMS4 catalogues. The data show no correlation between the peak of the inverse Compton emission and its luminosity. For the gamma-ray detected radio galaxies the luminosities in the various bands are correlated, except for the UV band, but there is no indication of a correlation of peak frequency or luminosity with the spectral slopes in the X-ray or gamma-ray band. The comparison with other bright radio galaxies shows that the gamma-ray detected objects are among those that have the largest X-ray but rather moderate radio fluxes. Their UV and X-ray luminosities are similar, but gamma-ray detected radio galaxies are predominantly of type FR-I, while the 3CRR sample contains mainly FR-II objects. The number counts of the so far gamma-ray detected radio galaxies shows a very shallow slope, indicating that potentially a fraction of radio galaxies has been missed so far or has not been identified as such, although the predicted number of 22 ± 7 is consistent with the observed 15 objects.

  4. 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...

  5. Gamma-Ray Bursts: The End Game

    Science.gov (United States)

    Lamb, Don

    1997-11-01

    The nature of gamma-ray bursts has been one of the greatest unsolved mysteries in astrophysics for more than a quarter century. A major reason for this is that no definite counterparts to the bursts could be found at other wavelengths, despite intense efforts spanning more than two decades. Consequently, the study of gamma-ray bursts has been isolated from the rest of astronomy. Scientists studying them have had only the laws of physics and the bursts themselves to guide them in attempting to solve the burst mystery. All of this changed dramatically with the discovery earlier this year of fading X-ray and optical sources in the arcminute-sized positional error boxes of several gamma-ray bursts. For the first time, temporal, as well as spatial, coincidence could be used to associate these X-ray and optical sources with the gamma-ray bursts. As a result, the odds are great that the fading X-ray and optical sources are counterparts of the bursts, and that the study of gamma-ray bursts has finally been connected with the rest of astronomy. In this talk, we describe the dramatic new information about the nature of gamma-ray bursts that the X-ray, optical, and radio observations of the fading sources have provided, and emphasize the implications that this information has for the distance scale to the bursts.

  6. Supernova remnants and gamma-ray sources

    CERN Document Server

    Torres, D F; Dame, T M; Combi, J A; Butt, Y M; Torres, Diego F.; Romero, Gustavo E.; Dame, Thomas M.; Combi, Jorge A.; Butt, Yousaf M.

    2003-01-01

    A review of the possible relationship between $\\gamma$-ray sources and supernova remnants (SNRs) is presented. Particular emphasis is given to the analysis of the observational status of the problem of cosmic ray acceleration at SNR shock fronts. All positional coincidences between SNRs and unidentified $\\gamma$-ray sources listed in the Third EGRET Catalog at low Galactic latitudes are discussed on a case by case basis. For several coincidences of particular interest, new CO(J=1-0) and radio continuum maps are shown, and the mass content of the SNR surroundings is determined. The contribution to the $\\gamma$-ray flux observed that might come from cosmic ray particles (particularly nuclei) locally accelerated at the SNR shock fronts is evaluated. We discuss the prospects for future research in this field and remark on the possibilities for observations with forthcoming $\\gamma$-ray instruments.

  7. Software tool for xenon gamma-ray spectrometer control

    Science.gov (United States)

    Chernysheva, I. V.; Novikov, A. S.; Shustov, A. E.; Dmitrenko, V. V.; Pyae Nyein, Sone; Petrenko, D.; Ulin, S. E.; Uteshev, Z. M.; Vlasik, K. F.

    2016-02-01

    Software tool "Acquisition and processing of gamma-ray spectra" for xenon gamma-ray spectrometers control was developed. It supports the multi-windows interface. Software tool has the possibilities for acquisition of gamma-ray spectra from xenon gamma-ray detector via USB or RS-485 interfaces, directly or via TCP-IP protocol, energy calibration of gamma-ray spectra, saving gamma-ray spectra on a disk.

  8. High Energy Radiation from $\\gamma$ Ray Bursts

    CERN Document Server

    Dermer, C D; Dermer, Charles D.; Chiang, James

    1999-01-01

    Gamma-ray burst (GRB) engines are probed most intimately during the prompt gamma-ray luminous phase when the expanding blast wave is closest to the explosion center. Using GRBs 990123 and 940217 as guides, we briefly review observations of high-energy emission from GRBs and summarize some problems in GRB physics. \\gamma\\gamma transparency arguments imply relativistic beaming. The parameters that go into the external shock model are stated, and we show numerical simulation results of gamma-ray light curves from relativistic blast waves with different amounts of baryon loading. A distinct component due to the synchrotron self-Compton process produces significant emission at GeV and TeV energies. Predictions for spectral and temporal evolution at these energies are presented for a blast wave expanding into uniform surroundings. Observations of the slow decay of GeV-TeV radiation provide evidence for ultra-high energy cosmic ray acceleration in GRBs.

  9. 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)

  10. Possibilities for inducing drought tolerance in wheat using gamma rays

    International Nuclear Information System (INIS)

    Drought is a limiting factor in the production of wheat in arid and semi-arid regions. Programme for improving this crop through mutations are taking place in many countries. Therefore, the present research was carried out to reveal the possibilities for inducing drought resistance in a local bread wheat cultivar (Giza-157) using gamma rays. The seed lots of this cultivar were irradiated with 0 (control), 75, 100 and 125 Gy of 60Co gamma rays and planted to produce M1 seed. In the following seasons, this process was repeated on fresh seed and the off-spring of M1 and M2 in such a way as to ensure the planting of the M1, M2 and M3 generations in one field experiment. To study the effect of drought, the second and fourth irrigations in the drought stressed treatment were withheld. The normal irrigation treatment consisted of four irrigations between planting and harvesting. The results showed that under drought stress irrigation conditions (especially at 125 Gy) significant earliness occurred in the M2 and M3 generations, which could be encouraging for inducing better drought tolerance. The mean weight of seed yield/plant increased at 100 and 200 Gy (M2) and at 100 Gy (M3) under drought conditions. The latter treatment produced the highest seed yield, i.e. better drought tolerance. It is concluded that inducing drought resistance in some cultivars of bread wheat using different doses of gamma ray can be recommended as a goal for inducing earliness, which could lead to a relatively good yield under drought conditions. 4 refs, 1 tab

  11. Atmospheric Cherenkov Gamma-ray Telescopes

    CERN Document Server

    Holder, Jamie

    2015-01-01

    The stereoscopic imaging atmospheric Cherenkov technique, developed in the 1980s and 1990s, is now used by a number of existing and planned gamma-ray observatories around the world. It provides the most sensitive view of the very high energy gamma-ray sky (above 30 GeV), coupled with relatively good angular and spectral resolution over a wide field-of-view. This Chapter summarizes the details of the technique, including descriptions of the telescope optical systems and cameras, as well as the most common approaches to data analysis and gamma-ray reconstruction.

  12. 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.

  13. Librarian driven analysis of gamma ray spectra

    International Nuclear Information System (INIS)

    For a set of a priori given radionuclides extracted from a general nuclide data library, the authors use median estimates of the gamma-peak areas and estimates of their errors to produce a list of possible radionuclides matching gamma ray line(s). The identification of a given radionuclide is obtained by searching for a match with the energy information of a database. This procedure is performed in an interactive graphic mode by markers that superimpose, on the spectral data, the energy information and yields provided by a general gamma ray data library. This library of experimental data includes approximately 17,000 gamma ray energy lines related to 756 known gamma emitter radionuclides listed by the ICRP. (author)

  14. On-line {sup 60}Co monitor for reactor recirculation system piping in primary containment vessel during reactor operation

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Katsunori, E-mail: katsunori.ueno.pa@hitachi.com [Hitachi Research Laboratory, Hitachi, Ltd., Hitachi 319-1224, Ibaraki (Japan); Tadokoro, Takahiro [Hitachi Research Laboratory, Hitachi, Ltd., Hitachi 319-1224, Ibaraki (Japan); Tsuyuki, Mizuho; Matsubara, Hirofumi; Ota, Nobuyuki; Nagase, Makoto [Hitachi-GE Nuclear Energy, Ltd., Hitachi 317-0073, Ibaraki (Japan)

    2014-10-15

    Highlights: • We developed an on-line {sup 60}Co monitor for reactor recirculation system piping during reactor operation. • Energy resolution at 1.4 × 10{sup 6} cps is 33 keV at 1332 keV using a pulse integral method. • A coincidence method is applied to reduce an effect of background gamma rays. • The coincidence counting of {sup 60}Co cascade gamma rays could be detected for a background dose rate of 4.8 mSv/h. - Abstract: Water chemistry control during reactor operation and installation of temporary radiation shielding prior to scheduled outages are carried out in order to reduce workers’ dose exposure caused by {sup 60}Co which is the main radiation source during scheduled outages of boiling water reactor (BWR) power plants. It is necessary to monitor the deposited {sup 60}Co on inner surfaces of reactor recirculation system (RRS) piping to evaluate effects of water chemistry control. We have developed an on-line {sup 60}Co monitor (OLCM) for this purpose. The OLCM applies a pulse integral method as a new method to measure gamma-ray counts of more than 1.0 × 10{sup 6} counts per second (cps) and a coincidence counting method to reduce an effect of background gamma rays caused by {sup 16}N in the measurement of {sup 60}Co cascade gamma rays. Energy resolution at 1.4 × 10{sup 6} cps is 33 keV using the pulse integral method and single LaBr{sub 3}:Ce scintillation detector. The energy resolutions of this detector using the fast response photo multiplier tube (PMT) are 50 keV at 1.5 × 10{sup 6} cps and 59 keV at 2.1 × 10{sup 6} cps. Furthermore, we measured the energy spectra using the pulse integral method, the coincidence counting method and two LaBr{sub 3}:Ce scintillation detectors and examined the transition of coincidence counting for {sup 60}Co detection under high dose rate during reactor operation at the Kyoto University Research Reactor (KUR). The coincidence counting of {sup 60}Co cascade gamma rays could be detected, and the result was

  15. 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)

  16. INTEGRAL & RXTE View of Gamma-ray Binaries

    OpenAIRE

    Jian LI; Torres, Diego F.; Zhang, Shu; WANG, JIANMIN

    2013-01-01

    Gamma-ray binaries are X-ray binaries with gamma-ray emissions. Their multi-wavelength emissions range from radio, optical, X-ray and to very high energy (TeV). X-ray emissions are crucial to understand the nature of gamma-ray binaries. INTEGRAL and RXTE have covered and monitored most of the gamma-ray binaries in hard and soft X-rays. Here we report the results of several gamma-ray binaries and possible gamma-ray binaries from INTEGRAL and RXTE.

  17. Gamma-Ray Astrophysics NSSTC Fermi GBM

    Data.gov (United States)

    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...

  18. Precision measurements of gamma-ray intensities

    International Nuclear Information System (INIS)

    To determine relative intensities of gamma rays in the region of 280 to 2750 keV, Ge(Li) detectors were calibrated with standard sources and cascade gamma-ray sources. Decay rates of the standard sources were determined by means of the 4πβ-γ or 4πX-γ coincidence method. Experimental conditions were improved and spectra were carefully analyzed. Relative gamma-ray intensities of 56Co, 88Y, sup(110m)Ag, 133Ba, 134Cs, 152Eu, 154Eu, 192Ir and 207Bi were determined within the accuracy of about 0.5% for strong gamma rays. Intensities per decays were obtained from the relative intensities for most of the nuclides. (author)

  19. Gamma-ray Irradiation Induces Useful Morphological Variation in Bermudagrass

    Directory of Open Access Journals (Sweden)

    Songul SEVER MUTLU

    2015-12-01

    Full Text Available Bermudagrass, Cynodon dactylon (L. Pers. is a widely used warm-season turfgrass species in warmer regions of the world. Gamma (ɣ irradiation has been used to generate useful variations in turfgrass breeding for various morphological traits. The objective of the present study was to measure and determine variations in morphology and turfgrass characteristics of a native drought resistant bermudagrass germplasm irradiated with 70, 90 or 110 Gy using a 60Co source. The stolons containing a single node were irradiated and immediately planted for regeneration in a greenhouse at the Akdeniz University, Antalya, Turkey. Selected mutants regenerated from the irradiated stolons were clonally propagated and transplanted into plastic pots for further observations of turfgrass characteristics.  Survival rates of stolons exposed to 70, 90 and 110 Gy were 76%, 43% and 17% respectively, 6 weeks after treatment. Dosages of 85 and 57 Gy were determined as LD50 and LD20 for the cuttings, respectively. The linear reduction of survival rate with increasing gamma-rays was highly correlated (r2=0.99. A total of four mutant lines (0.3 % of the irradiated plants showed a distinct dwarfed growth habit. Three of these lines were originated from 70 Gy and one from 110 Gy. These mutant lines exhibited more dwarf growth habit, higher shoot density, finer leaf texture than parental genotype. Mutant lines developed in this study can be used for the development of improved bermudagrass cultivars for landscaping and sports turf.

  20. Sensitivity of watermelon variety Bojura to mutant agents 60Co and EMS

    OpenAIRE

    Nikolay Velkov; Nasya Tomlekova; Fatma Sarsu

    2016-01-01

    A study on the sensitivity of watermelon variety Bojura to mutagenic agents was carried out in 2013-2014. The goal was to establish effective doses for mutagenic treatment of dry seeds with 60Co gamma rays (80, 100, 200, 250, 350 and 450 Gy) and swollen seeds with water for 24 hours were treated with ethyl methanesulfonate (EMS) at a concentration of 2%. Dominant mutations were not observed in the M1 generation. Morphological changes in 14 of 1395 M2 plants were observed. Phenotypic variation...

  1. Supernovae and gamma-ray bursts connection

    Science.gov (United States)

    Valle, Massimo Della

    2015-12-01

    I'll review the status of the Supernova/Gamma-Ray Burst connection. Several pieces of evidence suggest that long duration Gamma-ray Bursts are associated with bright SNe-Ic. However recent works suggest that GRBs might be produced in tight binary systems composed of a massive carbon-oxygen cores and a neutron star companion. Current estimates of the SN and GRB rates yield a ratio GRB/SNe-Ibc in the range ˜ 0.4% - 3%.

  2. Compton scattering gamma-ray source optimization

    Science.gov (United States)

    Hartemann, Frederic; Wu, Sheldon; Albert, Félicie; Barty, Chris

    2012-10-01

    The interaction of a bright relativistic electron beam with an intense laser pulse via Compton scattering can generate tunable gamma-rays for precision nuclear photonics applications. The properties of the gamma-ray phase space will be outlined, in relation with the 6D electron bunch and 6D laser pulse phase space, along with collimation, nonlinear effects and other sources of spectral broadening. Optimization strategies will be outlines within the context of nuclear photonics applications.

  3. Supernovae and gamma-ray bursts connection

    Energy Technology Data Exchange (ETDEWEB)

    Valle, Massimo Della [INAF-Napoli, Capodimonte Observatory, Salita Moiariello, 16, I-80131 Napoli (Italy); International Center for Relativistic Astrophysics Network, Piazzale della Repubblica 10, I-65122, Pescara (Italy)

    2015-12-17

    I’ll review the status of the Supernova/Gamma-Ray Burst connection. Several pieces of evidence suggest that long duration Gamma-ray Bursts are associated with bright SNe-Ic. However recent works suggest that GRBs might be produced in tight binary systems composed of a massive carbon-oxygen cores and a neutron star companion. Current estimates of the SN and GRB rates yield a ratio GRB/SNe-Ibc in the range ∼ 0.4% − 3%.

  4. Egret observations of the extragalactic gamma-ray emission

    DEFF Research Database (Denmark)

    Sreekumar, P.; Bertsch, D.L.; Dingus, B.L.;

    1998-01-01

    The all-sky survey in high-energy gamma rays (E > 30 MeV) carried out by EGRET aboard the Compton Gamma Ray Observatory provides a unique opportunity to examine in detail the diffuse gamma-ray emission. The observed diffuse emission has a Galactic component arising from cosmic-ray interactions...... likely explanation for the origin of this extragalactic high-energy gamma-ray emission is that it arises primarily from unresolved gamma-ray-emitting blazars....

  5. Study of the effect of gamma irradiation ({sup 60} Co) on the quality of sugar cane spirit and on the cask of maturation; Estudo do efeito da irradiacao gamma ({sup 60} Co) na qualidade da cachaca e no tonel de envelhecimento

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Mariana Branco de; Horii, Jorge; Alcarde, Andre Ricardo [Universidade de Sao Paulo (USP), Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Dept.de Agroindustria, Alimentos e Nutricao]. E-mails: jhorii@esalq.usp.br; aralcard@esalq.usp.br

    2006-10-15

    The ageing or maturing process of drink improves the sensorial characteristics of the product making it a qualified drink with higher economical value. The traditional maturing method of drinks involves their interaction with wood and irradiation can accelerate this ageing process. Sugar cane spirit and oak barrels with a 20 L capacity were treated using gamma irradiation (150 Gy). Physical-chemical and chromatographic analyses were constantly performed for 390 days during the drink ageing period. The sugar cane spirit and barrel irradiation did not change most volatile components of the same type coefficient such as volatile acidity, esters, superior alcohols and furfural throughout the 390 days. There is evidence, however, that some component parameters like aldehydes, tannin, color and copper concentration are in some way influenced resulting in partial acceleration of the ageing or maturing process. At the end of the ageing period, a sensorial analysis was made using 30 non-trained people who tasted the drink. The ageing process acceleration was confirmed by the sensorial evaluation, where the irradiated sugar cane spirit and/or barrel had higher approval regarding all parameters analyzed (scent, flavor and appearance). (author)

  6. The blazar gamma-ray luminosity function and the diffuse extragalactic gamma-ray background

    Science.gov (United States)

    Salamon, M. H.; Stecker, F. W.

    1994-01-01

    We have used the data from the new EGRET catalog on 'grazars' (blazers which are observed to be high-energy gamma-ray sources), together with radio data, to construct a new relation between radio and gamma-ray luminosity for these sources. Using this relation to construct a grazar gamma-ray luminosity function, we then calculate the contribution of unresolved grazars to the cosmic gamma-ray background radiation. We derive the energy spectrum of this background component above 100 MeV and the angular fluctuations in this background implied by our model.

  7. Cosmic gamma-ray studies at Srinagar

    International Nuclear Information System (INIS)

    Cosmic gamma ray studies being carried out at the Nuclear Research Laboratory at Srinagar and Gulmarg are described and some of the results of observation and possible conclusions are mentioned. These studies use ground base techniques which can detect short-time scale gamma ray bursts from supernovae and primordial black hole (PBH) and also high energy gamma rays from various point sources. A large area photomultiplier system is employed to detect pulses of visible fluorescence radiation which is caused by a gamma ray burst of supernovae of PBH origin. However, any signal out a large number of signals recorded at Gulmarg could not be identified as coinciding with any such event observed elsewhere. It shows that the size of the burst source cannot exceed 30 km., which is in agreement with neutron-star source models. An array using plastic scintillator detectors at the corner of a 10 metre square has been set up at Gulmarg to detect air-shower due to high energy gamma rays. Cerenkov light pulses recorded at Gulmarg have been projected on the sidereal map. A significant excess observed in the right ascension range 20 +- 3 h suggests the possible presence of a quasic-periodic source of gamma rays of energy greater than 1014 eV in the general direction of Cygnus X-3. Future programme of studies is mentioned. (K.M.)

  8. Gamma-ray pulsar studies with COMPTEL

    Science.gov (United States)

    Hermsen, W.; Kuiper, L.; Diehl, R.; Lichti, G.; Schoenfelder, V.; Strong, A. W.; Connors, A.; Ryan, J.; Bennett, K.; Busetta, M.; Carraminana, A.; Buccheri, R.; Grenier, I. A.

    1994-06-01

    Since the launch of the Compton Gamma-Ray Observatory (CGRO) the number of detected gamma-ray pulsars increased from two to six. COMPTEL, on-board CGRO and sensitive to gamma-rays with energies between approximately 0.7 and 30 MeV, detected three of these unambiguously. The classical Crab and Vela pulsars have been observed on several occasions and detailed pulse patterns and spectral parameters have been derived. The new CGRO gamma-ray pulsar PSR B1509-58 has been detected by COMPTEL at a significance level above 4 sigma, consistently in a timing and spatial analysis. A likely detection of Geminga has been obtained at an approximately 3 sigma level. This indication is found in a phase interval in which COS B data showed the presence of a new variable component, Interpeak 2, exhibiting a very soft spectrum above 50 MeV. The diversities in light-curve sphapes and spectral distributions, the apparent time variabilities, and the significant differences in the fractions of the spin-down power radiated at gamma-ray energies in this small sample of gamma-ray pulsars pose important constraints to pulsar modeling.

  9. Ferrous sulphate (Fricke) dosimetry in a fast neutron and a 60Co radiotherapeutical beams

    International Nuclear Information System (INIS)

    Ferrous sulphate (Fricke) dosimetry was performed in the fast neutron beam produced at the U-120 cyclotron of the Institute of Nuclear Physics and in a 60Co gamma-ray therapeutical beam at the Centre of Oncology in Krakow. The G-value was measured for the neutron component in the mixed (neutron + gamma) field of the fast neutron beam, where the mean neutron energy is 5.6 MeV. This value is Gn = 8.1 ± 0.8. Track structure theory calculations were made using energy spectra of charged secondary particles generated in water by the MRC Hammersmith fast neutron beam (mean neutron energy 7.6 MeV, measured value of Gn = 9.4 ± 0.6), yielding the calculated value of Gn = 8.61. Fricke dosimetry of the 60Co beam indicates that the absolute value of gamma-ray dose at the Centre of Oncology may be underestimated by about 3% . 19 refs., 1 tab. (author)

  10. Development of an analytical model for the determination of {sup 60}Co in aqueous samples by atomic absorption and gamma spectrometry techniques; Elaboracion de un modelo analitico para la determinacion de {sup 60}Co en muestras acuosas mediante tecnicas de absorcion atomica y espectrometria gamma

    Energy Technology Data Exchange (ETDEWEB)

    Solis A, N. A.

    2015-07-01

    The applications of the nuclear energy in industry and medicine generate radioactive wastes that must be isolated and confined in order to limit its spread in the biosphere. These types of wastes are generated in hospitals, industry, research centers and nuclear power plants (during de fuel cycle). The radioactive elements (radionuclides) cannot be destroyed by any known method, either chemical or mechanical. Its final destruction is produced by radioactive decay, which makes them stable isotopes, or nuclear transmutation being bombarded with atomic particles. Consequently, the radioactive waste management is to control the radioactive discharges and reduce to tolerable limits, eliminating of effluents and wastes the radionuclides of interest, concentrating them so they can be stored or evacuated so that later not appear in dangerous concentration in the biosphere. In Mexico, the main generators of radioactive wastes are the nuclear power plant of Laguna Verde in Veracruz, Hospitals of the public and private sector, in addition Instituto Nacional de Investigaciones Nucleares (ININ) some institutes and facilities of the UNAM and Instituto Politecnico Nacional (IPN) and industries among others. The aqueous radioactive wastes, particularly those from the nuclear power plants contain traces of cobalt-60. Currently there is no model or analytical technique for the separation of this radionuclide, so it became necessary to develop an analytical model for separation and facilitate their disposal. In this paper was shown that atomic absorption and gamma spectrometry techniques can separate the active concentration of the inactive, which is important because the total concentration can be associated through direct relationships with the wear of metal parts of the nuclear reactor, since the metal alloys of the same reactor containing a fraction of cobalt. Also this analytical and mathematical model that can be reproducible and applicable to full sets of samples and that this

  11. Microstructural study of Y1Ba2Cu3O7-x/Ag samples irradiated with 60Co γ rays at high doses

    International Nuclear Information System (INIS)

    We have investigated the damage induced by irradiation in Y1Ba2Cu3O7-x silver added samples. The samples were prepared with 0 and 6.5 wt% of silver and irradiated by high-energy γ irradiation (50-150 Mrad). The roles of silver and dosage irradiation are discussed in terms of their effects on microstructure, crystallinity, critical temperature (Tc) and zero-resistance temperature (T0). After irradiation, Tc decreased while the room-temperature electrical resistance increased by a factor of 8 for some of the samples. The difference in T0 between irradiated and non-irradiated YBCO samples was of the order of 10 K. We have found that the difference is bigger for silver-added samples. We have also observed several changes in diffraction patterns of YBCO and YBCO-silver samples. SEM images, EDS and XPS analysis showed that silver resided inside the grains as single atoms and as metallic clusters. The relative concentrations of the elements in samples were quantified by Auger electron spectroscopy. The values showed a gradual increase for radiation doses ranging between 0 and 100 Mrad. For doses up to 100 Mrad, Jc decreased because of the weak-link breakage induced by high doses of γ rays. (author)

  12. Effect of gamma radiation from {sup 60}C in conservation and quality of pepper fresh and pulp; Efeito da radiacao gama do {sup 60}Co na conservacao e qualidade de pimenta in natura e em polpa

    Energy Technology Data Exchange (ETDEWEB)

    Milagres, Regina Celia Rodrigues de Miranda

    2014-07-01

    Capsicum peppers are among the most used and most valued seasoning spices in the world. They are highly susceptible to post harvest decay, therefore the use of irradiation may contribute to conservation of this fruit which has significant nutritional, economic and social value. Were evaluated the effects of gamma radiation of {sup 60}Co in increasing the shelf-life and preservation of quality of pepper 'Dedo-de-moca' (Capsicum baccatum var. Pendulum) fresh and pulp associated or not with another conservation methods. Gamma radiation doses were investigated of 0,25; 0,50; 0,75; 1,00; 1,25; 1,50; 2,00 e 3,00 kGy in fresh fruit and 1,50; 2,00; 3,00; 4,50 e 6,00 kGy in pepper pulp. The use of laboratory pasteurization (85°C/3min), the addition of citric acid (5%) and 5% NaCl were also investigated in the pepper pulp. The samples were stored at 5 °C and or 25 °C. Were performed analysis: visual (disease incidence, turgidity and color); bioactive compounds (carotenoids, capsaicinoids, antioxidant capacity and phenolic compounds); physicochemical (Weight loss, firmness, soluble solids (SS), pH, titratable acidity (TA), ratio, color and moisture); respiratory rate and ethylene production; proximate composition (moisture, soluble and insoluble fiber, ash, protein, ether extract, total and available carbohydrate); microbiological contamination (mesophilic aerobic microorganisms, coliforms at 45 °C, Salmonella spp. and yeasts and molds) and sensory (acceptance test, difference test and paired preference). Radiation doses between 0.25 and 3.00 kGy were not effective to increase shelf-life and maintain fresh pepper quality during storage. There was increased intensity of red color, of incidence of disease, decreased turgidity and changes in physical, chemical and nutritional parameters. In pulp, the doses of gamma radiation of 4.50 and 6.00 kGy and the addition of 5% NaCl no changing sensory attributes, physical-chemical and bioactive compounds. Only the

  13. Studies of Cosmic Rays with GeV Gamma Rays

    CERN Document Server

    Tajima, Hiroyasu; Finazzi, Stefano; Cohen-Tanugi, Johann; Chiang, James

    2007-01-01

    We describe the role of GeV gamma-ray observations with GLAST-LAT (Gamma-ray Large Area Space Telescope - Large Area Telescope) in identifying interaction sites of cosmic-ray proton (or hadrons) with interstellar medium (ISM). We expect to detect gamma rays from neutral pion decays in high-density ISM regions in the Galaxy, Large Magellanic Cloud, and other satellite galaxies. These gamma-ray sources have been detected already with EGRET (Energetic Gamma Ray Experiment Telescope) as extended sources (eg. LMC and Orion clouds) and GLAST-LAT will detect many more with a higher spatial resolution and in a wider spectral range. We have developed a novel image restoration technique based on the Richardson-Lucy algorithm optimized for GLAST-LAT observation of extended sources. Our algorithm calculates PSF (point spread function) for each event. This step is very important for GLAST-LAT and EGRET image analysis since PSF varies more than one order of magnitude from one gamma ray to another depending on its energy as...

  14. Determination of the correction factor for attenuation, dispersion and production of electrons (Kwall) in the wall of graphite of a ionization chamber Pattern National Type CC01 in fields of gamma radiation of 60Co

    International Nuclear Information System (INIS)

    It was determined the Kwall correction factor for the wall of graphite of the chamber of the pattern national type CC01 series 133 for a radiation field Gamma of 60Co. With this end to measured the currents of ionization l(x) as function of the thickness of the wall of the chamber: X=4,8,12,16 and 20 mm.The mensurations for each thickness consisting of three groups, of sizes n = 30 or 60 data for each group; obtaining 8 complete groups of mensurations independent in eight different dates.The determinate the factor carried out using three regression models: lineal, logarithmic and quadratic, models that were tried to validate with the tests of : i) Shapiro-Wilk and χ2 for the normality of the entrance data ii) Tests of Bartlett for variances homogeneity among groups for each thickness iii) The tests of Duncan for the stockings among groups of each thickness, and iv) The tests of adjustment lack (LOF) for the models used. Nevertheless, alone the models of the group of corresponding mensurations at 01-03-2000 17-08-2001 they can be validated by LOF, but not for tests of normality and homogeneity of variances. Among other assignable causes of variation we have: i) The values captured by the system of mensuration of the variables of it influences: pressure, temperature and relative humidity dont belong together with the existent ones to the moment to capture the l(x). ii) The mensuration room presents flows of air, for what was suited o diminish their volume and to eliminate the flows of air. iii) A protocol settled down of taking of measures that it consisted in: - Pre-irradiation 5 minutes the chamber after the change of polarity and hood change, with a period of stabilization of 5 minutes after the pre-irradiation. - Pre-irradiation for 5 minutes before the taking of the readings, with the object of eliminating variation sources assigned to currents of escapes or due variations to transitory. iv) To realize corrections for relative humidity of agreement with the

  15. Gamma-ray attenuation coefficients of some building materials available in Egypt

    International Nuclear Information System (INIS)

    Mass attenuation coefficients of various types of building materials were measured using a high-resolution HPGe spectrometer detector. Samples were irradiated by gamma-rays emitted from point sources of 241Am, 133Ba, 60Co and 137Cs. The results are in good agreement with the theoretical calculations of XCOM code. The effectiveness of building materials in shielding were determined over the range 50-3000 keV. Finally, the protection efficiency of walls and roofs from radiation exposure were determined. The effectiveness of all tested building materials was better than the internationally accepted limit, and they are therefore acceptable for use.

  16. Estudo do efeito da irradiação gamma (60CO na qualidade da cachaça e no tonel de envelhecimento Study of the effect of gamma irradiation (60co on the quality of sugar cane spirit and on the cask of maturation

    Directory of Open Access Journals (Sweden)

    Mariana Branco de Miranda

    2006-12-01

    Full Text Available O processo de envelhecimento ou maturação das bebidas proporciona uma melhora nas características sensoriais da cachaça, tornando-a de qualidade superior e de maior valor econômico. O método tradicional de maturação de bebidas é sua interação com madeiras, sendo que a irradiação pode acelerar este processo de envelhecimento. A cachaça e os tonéis de carvalho de 20 L de capacidade foram submetidos à irradiação gama (150 Gy. Análises físico-químicas e cromatográficas foram realizadas periodicamente ao longo de 390 dias do período de envelhecimento da bebida. A irradiação da cachaça e do tonel não alterou a maioria dos componentes voláteis do coeficiente de congêneres como acidez volátil, ésteres, álcoois superiores e furfural durante os 390 dias. Há evidências, entretanto, de que os parâmetros de alguns componentes como aldeídos, taninos, cor e teor de cobre são de alguma forma influenciados, resultando em aceleração parcial do processo de maturação ou envelhecimento. Ao final do período de envelhecimento, foi feita uma análise sensorial com 30 provadores não treinados. A aceleração do processo de envelhecimento foi confirmada pela avaliação sensorial, e a cachaça e/ou tonel irradiados receberam maior indicação de aprovação em todos os parâmetros analisados (aroma, sabor e aparência.The ageing or maturing process of drink improves the sensorial characteristics of the product making it a qualified drink with higher economical value. The traditional maturing method of drinks involves their interaction with wood and irradiation can accelerate this ageing process. Sugar cane spirit and oak barrels with a 20 L capacity were treated using gamma irradiation (150 Gy. Physical-chemical and chromatographic analyses were constantly performed for 390 days during the drink ageing period. The sugar cane spirit and barrel irradiation did not change most volatile components of the same type coefficient such

  17. GRI: the gamma-ray imager mission

    CERN Document Server

    Knödlseder, J

    2006-01-01

    Observations of the gamma-ray sky reveal the most powerful sources and the most violent events in the Universe. While at lower wavebands the observed emission is generally dominated by thermal processes, the gamma-ray sky provides us with a view on the non-thermal Universe. Here particles are accelerated to extreme relativistic energies by mechanisms which are still poorly understood, and nuclear reactions are synthesizing the basic constituents of our world. Cosmic accelerators and cosmic explosions are the major science themes that are addressed in the gamma-ray regime. With the INTEGRAL observatory, ESA has provided a unique tool to the astronomical community revealing hundreds of sources, new classes of objects, extraordinary views of antimatter annihilation in our Galaxy, and fingerprints of recent nucleosynthesis processes. While INTEGRAL provides the global overview over the soft gamma-ray sky, there is a growing need to perform deeper, more focused investigations of gamma-ray sources. In soft X-rays a...

  18. New insights from cosmic gamma rays

    Science.gov (United States)

    Roland, Diehl

    2016-04-01

    The measurement of gamma rays from cosmic sources at ~MeV energies is one of the key tools for nuclear astrophysics, in its study of nuclear reactions and their impacts on objects and phenomena throughout the universe. Gamma rays trace nuclear processes most directly, as they originate from nuclear transitions following radioactive decays or high-energy collisions with excitation of nuclei. Additionally, the unique gamma-ray signature from the annihilation of positrons falls into this astronomical window and is discussed here: Cosmic positrons are often produced from β-decays, thus also of nuclear physics origins. The nuclear reactions leading to radioactive isotopes occur inside stars and stellar explosions, which therefore constitute the main objects of such studies. In recent years, both thermonuclear and core-collapse supernova radioactivities have been measured though 56Ni, 56Co, and 44Ti lines, and a beginning has thus been made to complement conventional supernova observations with such measurements of the prime energy sources of supernova light created in their deep interiors. The diffuse radioactive afterglow of massive-star nucleosynthesis in gamma rays is now being exploited towards astrophysical studies on how massive stars feed back their energy and ejecta into interstellar gas, as part of the cosmic cycle of matter through generations of stars enriching the interstellar gas and stars with metals. Large interstellar cavities and superbubbles have been recognised to be the dominating structures where new massive-star ejecta are injected, from 26Al gamma-ray spectroscopy. Also, constraints on the complex interiors of stars derive from the ratio of 60Fe/26Al gamma rays. Finally, the puzzling bulge-dominated intensity distribution of positron annihilation gamma rays is measured in greater detail, but still not understood; a recent microquasar flare provided evidence that such objects may be prime sources for positrons in interstellar space, rather than

  19. Gamma Ray Bursts in the HAWC Era

    CERN Document Server

    Mészáros, Peter; Murase, Kohta; Fox, Derek; Gao, He; Senno, Nicholas

    2015-01-01

    Gamma-Ray Bursts are the most energetic explosions in the Universe, and are among the most promising for detecting multiple non-electromagnetic signals, including cosmic rays, high energy neutrinos and gravitational waves. The multi-GeV to TeV gamma-ray range of GRB could have significant contributions from hadronic interactions, mixed with more conventional leptonic contributions. This energy range is important for probing the source physics, including overall energetics, the shock parameters and the Lorentz factor. We discuss some of the latest observational and theoretical developments in the field.

  20. TeV Gamma-Ray Astrophysics

    CERN Document Server

    Ribó, M

    2008-01-01

    The window of TeV Gamma-Ray Astrophysics was opened less than two decades ago, when the Crab Nebula was detected for the first time. After several years of development, the technique used by imaging atmospheric Cherenkov telescopes like HESS, MAGIC or VERITAS, is now allowing to conduct sensitive observations in the TeV regime. Water Cherenkov instruments like Milagro are also providing the first results after years of integration time. Different types of extragalactic and galactic sources have been detected, showing a variety of interesting phenomena that are boosting theory in very high energy gamma-ray astrophysics. Here I review some of the most interesting results obtained up to now, making special emphasis in the field of X-ray/gamma-ray binaries.

  1. Gamma ray astronomy and the origin of galactic cosmic rays

    International Nuclear Information System (INIS)

    Diffusive shock acceleration operating at expanding supernova remnant shells is by far the most popular model for the origin of galactic cosmic rays. Despite the general consensus received by the model, an unambiguous and conclusive proof of the supernova remnant hypothesis is still missing. In this context, the recent developments in gamma ray astronomy provide us with precious insights into the problem of the origin of galactic cosmic rays, since production of gamma rays is expected both during the acceleration of cosmic rays at supernova remnant shocks and during their subsequent propagation in the interstellar medium. In particular, the recent detection of a number of supernova remnants at TeV energies nicely fits with the model, but it still does not constitute a conclusive proof of it, mainly due to the difficulty of disentangling the hadronic and leptonic contributions to the observed gamma ray emission. The main goal of my research is to search for an unambiguous and conclusive observational test for proving (or disproving) the idea that supernova remnants are the sources of galactic cosmic rays with energies up to (at least) the cosmic ray knee. Our present comprehension of the mechanisms of particle acceleration at shocks and of the propagation of cosmic rays in turbulent magnetic fields encourages beliefs that such a conclusive test might come from future observations of supernova remnants and of the Galaxy in the almost unexplored domain of multi-TeV gamma rays. (author)

  2. Fluorescence in situ hybridization detection of chromosome translocations induced by 60Co γ-rays in human lymphocytes dose-response curve and persistence%用荧光原位杂交技术建立60Coγ射线诱发人外周血淋巴细胞染色体易位率剂量效应曲线及易位的持续性研究

    Institute of Scientific and Technical Information of China (English)

    王晓琳; 李进; 王知权

    2001-01-01

    Objective To study dose-response relationship for chromosome translocation and its persistence measured in human lymphocytes exposed to 60Co γ-rays.Methods The chromosome translocations in human peripheral lymphocytes were detected by fluorescence in situ hybridization using 4# and 7# combination of composite whole chromosome-specific DNA probes and Giemsa stain.Results The dose-response relationship for chromosome translocation induced by 60Co γ-rays in vitro could be described by the function:Y=0.0030+0.0134D+0.0165D2.The frequencies of chromosome translocations induced by 0.5 and 2 Gy γ-irradiation did not diminish over time,so it exhibited excellent persistence.Conclusions The results indicate that retrospective dose-reconstruction can be accomplished using chromosome translocation frequency.%目的研究不同剂量60Coγ射线诱发人外周血淋巴细胞染色体易位率和辐射剂量间的剂量效应关系以及观察易位率在同一剂量、不同时相点的变化。方法采用荧光原位杂交技术和连续Giemsa法,用4号和7号全染色体探针分析0、0.25、0.5、0.75、1和2 Gy 60Coγ射线离体照射诱发人外周血淋巴细胞染色体易位率,同时对两个剂量点进行52和72 h培养,比较其易位率。结果易位率和辐射剂量间的量效关系可以用一个二次多项式方程Y=0.0030+0.0134D+0.0165D2来描述;易位率在52和72 h培养时差异无显著性。结论易位率和辐射剂量间存在良好的量效关系,可作为进行早先照射剂量重建的理论依据。

  3. On the difference between gamma-ray-detected and non-gamma-ray-detected pulsars

    CERN Document Server

    Rookyard, Simon C; Johnston, Simon; Kerr, Matthew

    2016-01-01

    We compare radio profile widths of young, energetic gamma-ray-detected and non-gamma-ray-detected pulsars. We find that the latter typically have wider radio profiles, with the boundary between the two samples exhibiting a dependence on the rate of rotational energy loss. We also find that within the sample of gamma-ray-detected pulsars, radio profile width is correlated with both the separation of the main gamma-ray peaks and the presence of narrow gamma-ray components. These findings lead us to propose that these pulsars form a single population where the main factors determining gamma ray detectability are the rate of rotational energy loss and the proximity of the line of sight to the rotation axis. The expected magnetic inclination angle distribution will be different for radio pulsars with and without detectable gamma rays, naturally leading to the observed differences. Our results also suggest that the geometry of existing radio and outer-magnetosphere gamma-ray emission models are at least qualitative...

  4. Gamma-Ray Lenses for Astrophysics-and the Gamma-Ray Imager Mission GRI

    DEFF Research Database (Denmark)

    Wunderer, C. B.; Ballmoos, P. V.; Barriere, N.;

    2009-01-01

    Observations of the gamma-ray sky reveal the most powerful sources and the most violent events in the Universe. While at lower wavebands the observed emission is generally dominated by thermal processes, the gamma-ray sky provides us with a view on the non-thermal Universe. Here particles are acc...

  5. Determination of the correction factor for attenuation, dispersion and production of electrons (K{sub wall}) in the wall of graphite of a ionization chamber Pattern National Type CC01 in fields of gamma radiation of {sup 60}Co; Determinacion del factor de correccion por atenuacion, dispersion y produccion de electrones (K{sub wall}) en la pared de grafito de una Camara de Ionizacion Patron Nacional Tipo CC01 en campos de radiacion gamma de {sup 60} Co

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez R, J.T.; Morales P, J.; Cruz E, P. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2001-12-15

    It was determined the Kwall correction factor for the wall of graphite of the chamber of the pattern national type CC01 series 133 for a radiation field Gamma of {sup 60}Co. With this end to measured the currents of ionization l(x) as function of the thickness of the wall of the chamber: X=4,8,12,16 and 20 mm.The mensurations for each thickness consisting of three groups, of sizes n = 30 or 60 data for each group; obtaining 8 complete groups of mensurations independent in eight different dates.The determinate the factor carried out using three regression models: lineal, logarithmic and quadratic, models that were tried to validate with the tests of : i) Shapiro-Wilk and {chi}{sup 2} for the normality of the entrance data ii) Tests of Bartlett for variances homogeneity among groups for each thickness iii) The tests of Duncan for the stockings among groups of each thickness, and iv) The tests of adjustment lack (LOF) for the models used. Nevertheless, alone the models of the group of corresponding mensurations at 01-03-2000 17-08-2001 they can be validated by LOF, but not for tests of normality and homogeneity of variances. Among other assignable causes of variation we have: i) The values captured by the system of mensuration of the variables of it influences: pressure, temperature and relative humidity don{sup t} belong together with the existent ones to the moment to capture the l(x). ii) The mensuration room presents flows of air, for what was suited o diminish their volume and to eliminate the flows of air. iii) A protocol settled down of taking of measures that it consisted in: - Pre-irradiation 5 minutes the chamber after the change of polarity and hood change, with a period of stabilization of 5 minutes after the pre-irradiation. - Pre-irradiation for 5 minutes before the taking of the readings, with the object of eliminating variation sources assigned to currents of escapes or due variations to transitory. iv) To realize corrections for relative humidity of

  6. The Infrared-Gamma-Ray Connection: A WISE View of the Extragalactic Gamma-Ray Sky

    CERN Document Server

    Massaro, F

    2016-01-01

    Using data from the WISE all-sky survey we discovered that the non-thermal infrared (IR) emission of blazars, the largest known population of extragalactic gamma-ray sources, has peculiar spectral properties. In this work, we confirm and strengthen our previous analyses using the latest available releases of both the WISE and the Fermi source catalogs. We also show that there is a tight correlation between the mid-IR colors and the gamma-ray spectral index of Fermi blazars. We name this correlation "the infrared--gamma-ray connection". We discuss how this connection links both the emitted powers and the spectral shapes of particles accelerated in jets arising from blazars over ten decades in energy. Based on this evidence, we argue that the infrared--gamma-ray connection is stronger than the well known radio--gamma-ray connection.

  7. A Search for Gamma-Ray Bursts and Pulsars, and the Application of Kalman Filters to Gamma-Ray Reconstruction

    OpenAIRE

    Jones, B B

    2002-01-01

    Part I describes the analysis of periodic and transient signals in EGRET data. A method to search for the transient flux from gamma-ray bursts independent of triggers from other gamma-ray instruments is developed. Several known gamma-ray bursts were independently detected, and there is evidence for a previously unknown gamma-ray burst candidate. Statistical methods using maximum likelihood and Bayesian inference are developed and implemented to extract periodic signals from gamma-ray sources ...

  8. 60Co levels in the seawater regions

    International Nuclear Information System (INIS)

    In order to assess the contribution from nuclear power facilities to the 60Co levels in seawater regions, it is essential to grasp the background values of 60Co. The following matters are described: 60Co sources and the respective inputs; nuclear test fallout and nuclear power plants; the 60Co levels in overseas countries; the 60Co levels in Japan; the 60Co levels from nuclear power plants in Fukui prefecture. In the seawater regions around Japan, there have been numerous instances of 60Co detection; several pCi/kg of dry earth in sea bottom earth and about 1 pCi/kg of raw material in marine life can be considered as the background levels due to nuclear test fallout and nuclear-powered submarines. In the seawater regions of Fukui prefecture, the 60Co levels appreciably exceeded the above background due to the nuclear power plants, which are insignificant concerning the radiation exposure of the local people. (Mori, K.)

  9. Status of the Milagro Gamma Ray Observatory

    CERN Document Server

    Maryland Univ. College Park

    2001-01-01

    The Milagro Gamma Ray Observatory, located at an altitude of 8,600 feet in the Jemez Mountains of New Mexico, is the world's first large-area water Cherenkov detector capable of continuously monitoring the entire sky for sources of TeV gamma rays. It is uniquely capable of searching for transient sources of VHE gamma rays. The core of the detector is a 60m x 80m x 8m pond instrumented with 723 PMTs deployed in two layers. This part of the detector is complete and has operated continuously since Jan. 2000. Initial studies including searches for gamma-ray sources are ongoing, and preliminary results are available. The final stage of construction is under way. We are deploying 170 auxiliary "outrigger" water Cherenkov detectors in an area of 40,000 square-meters surrounding the pond, which will significantly enhance our ability to reject background and more accurately reconstruct the gamma-ray direction and energy. In addition, we are lowering the energy threshold of the detector by using custom processing to en...

  10. Stellar Photon Archaeology with Gamma-Rays

    Science.gov (United States)

    Stecker, Floyd W.

    2009-01-01

    Ongoing deep surveys of galaxy luminosity distribution functions, spectral energy distributions and backwards evolution models of star formation rates can be used to calculate the past history of intergalactic photon densities and, from them, the present and past optical depth of the Universe to gamma-rays from pair production interactions with these photons. The energy-redshift dependence of the optical depth of the Universe to gamma-rays has become known as the Fazio-Stecker relation (Fazio & Stecker 1970). Stecker, Malkan & Scully have calculated the densities of intergalactic background light (IBL) photons of energies from 0.03 eV to the Lyman limit at 13.6 eV and for 0$ < z < $6, using deep survey galaxy observations from Spitzer, Hubble and GALEX and have consequently predicted spectral absorption features for extragalactic gamma-ray sources. This procedure can also be reversed. Determining the cutoff energies of gamma-ray sources with known redshifts using the recently launched Fermi gamma-ray space telescope may enable a more precise determination of the IBL photon densities in the past, i.e., the "archaeo-IBL.", and therefore allow a better measure of the past history of the total star formation rate, including that from galaxies too faint to be observed.

  11. Gamma-Ray Astronomy from the Ground

    CERN Document Server

    Horns, D

    2016-01-01

    The observation of cosmic gamma-rays from the ground is based upon the detection of gamma-ray initiated air showers. At energies between approximately $10^{11}$ eV and $10^{13}$ eV, the imaging air Cherenkov technique is a particularly successful approach to observe gamma-ray sources with energy fluxes as low as $\\approx 10^{-13}$ erg\\,cm$^{-2}\\,$s$^{-1}$. The observations of gamma-rays in this energy band probe particle acceleration in astrophysical plasma conditions and are sensitive to high energy phenomena beyond the standard model of particle physics (e.g., self-annihilating or decaying dark matter, violation of Lorentz invariance, mixing of photons with light pseudo-scalars). The current standing of the field and its major instruments are summarised briefly by presenting selected highlights. A new generation of ground based gamma-ray instruments is currently under development. The perspectives and opportunities of these future facilities will be discussed.

  12. Application of gamma-ray transmission method for study the properties of cultivated soil

    International Nuclear Information System (INIS)

    Highlights: ► Gamma-ray transmission method and attenuation coefficients. ► Physical properties of cultivated soil. ► Soil–water systems management. - Abstract: The objective of the proposed work was to apply gamma-ray transmission method for studying the properties of cultivated soil. In this study, mass attenuation coefficients, bulk density, moisture content, porosity, and field capacity are determined. Five soil samples are collected from different agriculture zones in Egypt. A high-resolution gamma-ray spectrometry based on HPGe (high purity germanium) detector was employed to measure attenuation of strongly collimated monoenergetic gamma beam through soil samples. The radioactive sources used in the experiment were 241Am, 133Ba, 137Cs and 60Co. The mass attenuation coefficients of soil samples were calculated from the transmission measurements. WinXCom program was used to calculate mass attenuation coefficients of soil samples. There is a satisfactory agreement between experimental and theoretical values. It was observed that gamma-ray transmission method is an efficient tool for studying soil parameters for agriculture purposes.

  13. Solution To The Gamma Ray Burst Mystery?

    CERN Document Server

    Dar, Arnon

    1996-01-01

    Photoexcitation and ionization of partially ionized heavy atoms in highly relativistic flows by interstellar photons, followed by their reemission in radiative recombination and decay, boost star-light into beamed $\\gamma$ rays along the flow direction. Repeated excitation/decay of highly relativistic baryonic ejecta from merger or accretion induced collapse of neutron stars in dense stellar regions (DSRs), like galactic cores, globular clusters and super star-clusters, can convert enough kinetic energy in such events in distant galaxies into cosmological gamma ray bursts (GRBs). The model predicts remarkably well all the main observed temporal and spectral properties of GRBs. Its success strongly suggests that GRBs are $\\gamma$ ray tomography pictures of DSRs in galaxies at cosmological distances with unprecedented resolution: A time resolution of $dt\\sim 1~ms$ in a GRB can resolve stars at a Hubble distance which are separated by only $D\\sim 10^{10}cm$. This is equivalent to the resolving power of an optica...

  14. New insights from cosmic gamma rays

    CERN Document Server

    Diehl, Roland

    2016-01-01

    The measurement of gamma rays from cosmic sources at MeV energies is one of the key tools for nuclear astrophysics, in its study of nuclear reactions and their impacts on objects and phenomena throughout the universe. Gamma rays trace nuclear processes most directly, as they originate from nuclear transitions following radioactive decays or high-energy collisions with excitation of nuclei. Additionally, the unique gamma-ray signature from the annihilation of positrons falls into this astronomical window and is discussed here: Cosmic positrons are often produced from beta-decays, thus also of nuclear physics origins. The nuclear reactions leading to radioactive isotopes occur inside stars and stellar explosions, which therefore constitute the main objects of such studies. In recent years, both thermonuclear and core-collapse supernova radioactivities have been measured, and complement conventional supernova observations with measurements of their prime energy sources. The diffuse radioactive afterglow of massi...

  15. Microsecond flares in gamma-ray bursts

    Science.gov (United States)

    Schaefer, Bradley E.; Cohen, Justin; Teegarden, Bonnard J.; Cline, Thomas L.; Fishman, Gerald J.; Meegan, Charles A.; Wilson, Robert B.; Paciesas, William S.; Pendleton, Geoffrey N.; Matteson, James L.

    1993-01-01

    It has been suggested that gamma-ray burst light curves may consist of many superposed flares with a duration shorter than 30/microsec. If true, the implications for the interpretation of burst data are enormous. With the launch of the Compton Gamma-Ray Observatory, four predictions of Mitrofanov's (1989) suggestion can be tested. Our results which contradict this suggestion are (1) the photon arrival times are not correlated between independent detectors, (2) the spectral hardness and intensity does not depend on the detector area, (3) the bursts seen by detectors which measure photon positions do not see microsecond flares, and (4) burst positions deduced from detectors with different projected areas are close to the positions deduced from time-of-flight differences between separated spacecraft. We conclude, therefore, that gamma-ray bursts are not composed of microsecond flares.

  16. Solar hard X-rays and gamma-rays

    Institute of Scientific and Technical Information of China (English)

    GAN; Weiqun(甘为群); CHANG; Jin(常进); LI; Youping(李友平); LIN; Chunmei(林春梅)

    2002-01-01

    We briefly introduce our recent work on the spectral evolution of energetic protons, the beam property of accelerated electrons, the gamma-ray flare classification, the temporal features of the annihilation line, the hard X-ray delayed events, the hydrodynamic process, and the continuum emission in solar flares.

  17. Sensitivity of watermelon variety Bojura to mutant agents 60Co and EMS

    Directory of Open Access Journals (Sweden)

    Nikolay Velkov

    2016-04-01

    Full Text Available A study on the sensitivity of watermelon variety Bojura to mutagenic agents was carried out in 2013-2014. The goal was to establish effective doses for mutagenic treatment of dry seeds with 60Co gamma rays (80, 100, 200, 250, 350 and 450 Gy and swollen seeds with water for 24 hours were treated with ethyl methanesulfonate (EMS at a concentration of 2%. Dominant mutations were not observed in the M1 generation. Morphological changes in 14 of 1395 M2 plants were observed. Phenotypic variations changes were the colour of the seed coat, chlorophyll disorders of cotyledons, leaves, petals, and alterations of the location of the fruit set in the central stem. Visible changes of the morphological characteristics of the fruit were not observed. The doses induced certain morphological changes, however, higher doses or combined gamma rays 60Co and EMS treatments would induce mutations more efficiently. Subsequent experiments are required to obtain mutants with changes that affect flowers and fruits. The results are important for increasing mutation efficiency in watermelon breeding.

  18. Design and Performance of the GAMMA-400 Gamma-Ray Telescope for the Dark Matter Searches

    CERN Document Server

    Galper, A M; Aptekar, R L; Arkhangelskaja, I V; Arkhangelskiy, A I; Boezio, M; Bonvicini, V; Boyarchuk, K A; Fradkin, M I; Gusakov, Yu V; Kaplin, V A; Kachanov, V A; Kheymits, M D; Leonov, A A; Longo, F; Mazets, E P; Maestro, P; Marrocchesi, P; Mereminskiy, I A; Mikhailov, V V; Moiseev, A A; Mocchiutti, E; Mori, N; Moskalenko, I V; Naumov, P Yu; Papini, P; Picozza, P; Rodin, V G; Runtso, M F; Sparvoli, R; Spillantini, P; Suchkov, S I; Tavani, M; Topchiev, N P; Vacchi, A; Vannuccini, E; Yurkin, Yu T; Zampa, N; Zverev, V G; Zirakashvili, V N

    2012-01-01

    The GAMMA-400 gamma-ray telescope is designed to measure the fluxes of gamma rays and cosmic-ray electrons + positrons, which can be produced by annihilation or decay of the dark matter particles, as well as to survey the celestial sphere in order to study point and extended sources of gamma rays, measure energy spectra of Galactic and extragalactic diffuse gamma-ray emission, gamma-ray bursts, and gamma-ray emission from the Sun. The GAMMA-400 covers the energy range from 100 MeV to 3000 GeV. Its angular resolution is ~0.01 deg (E{\\gamma} > 100 GeV), the energy resolution ~1% (E{\\gamma} > 10 GeV), and the proton rejection factor ~10E6. GAMMA-400 will be installed on the Russian space platform Navigator. The beginning of observations is planned for 2018.

  19. Design and Performance of the GAMMA-400 Gamma-Ray Telescope for Dark Matter Searches

    Science.gov (United States)

    Galper, A. M.; Adriani, O.; Aptekar, R. L.; Arkhangelskaja, I. V.; Arkhangelskiy, A. I.; Boezio, M.; Bonvicini, V.; Boyarchuk, K. A.; Fradkin, M. I.; Gusakov, Yu V.; Kaplin, V. A.; Kachanov, V. A.; Kheymits, M. D.; Leonov, A. A.; Longo, F.; Mazets, E. P.; Maestro, P.; Marrocchesi, P.; Mereminskiy, I. A.; Mikhailov, V. V.; Mocchiutti, E.; Moiseev, A. A.; Mori, N.; Moskalenko, I. V.; Naumov, P. Yu

    2012-01-01

    The GAMMA-400 gamma-ray telescope is designed to measure the fluxes of gamma-rays and cosmic-ray electrons (+) positrons, which can be produced by annihilation or decay of the dark matter particles, as well as to survey the celestial sphere in order to study point and extended sources of gamma-rays, measure energy spectra of Galactic and extragalactic diffuse gamma-ray emission, gamma-ray bursts, and gamma-ray emission from the Sun. GAMMA-400 covers the energy range from 100 MeV to 3000 GeV. Its angular resolution is approximately 0.01deg (E(sub gamma) greater than 100 GeV), the energy resolution approximately 1% (E(sub gamma) greater than 10 GeV), and the proton rejection factor approximately 10(exp 6). GAMMA-400 will be installed on the Russian space platform Navigator. The beginning of observations is planned for 2018.

  20. Gamma-Ray Bursts: Jets and Energetics

    CERN Document Server

    Frail, D A

    2003-01-01

    The relativistic outflows from gamma-ray bursts are now thought to be narrowly collimated into jets. After correcting for this jet geometry there is a remarkable constancy of both the energy radiated by the burst and the kinetic energy carried by the outflow. Gamma-ray bursts are still the most luminous explosions in the Universe, but they release energies that are comparable to supernovae. The diversity of cosmic explosions appears to be governed by the fraction of energy that is coupled to ultra-relativistic ejecta.

  1. Very high energy gamma ray astrophysics

    International Nuclear Information System (INIS)

    The Whipple Observatory High Resolution Camera will be used in a vigorous program of observations to search for new sources of very-high-energy gamma rays. In addition, a search for antimatter using the moon-earth system as an ion spectrometer will be begun. The first phase of GRANITE, the new 37-element 11-m camera, will be concluded with first light scheduled for September, 1991. The two cameras will operate in support of the Gamma Ray Observatory mission in the winter of 1991/2

  2. A Shotgun Model for $\\gamma$ Ray Bursts

    CERN Document Server

    Heinz, S

    1999-01-01

    We propose that gamma ray bursts (GRBs) are produced by a shower of heavy blobs running into circumstellar material at highly relativistic speeds. The gamma ray emission is produced in the shocks these bullets drive into the surrounding medium. The short term variability seen in GRBs is set by the slowing-down time of the bullets while the overall duration of the burst is set by the lifetime of the central engine. A requirement of this model is that the ambient medium be dense, consistent with a strong stellar wind. In contrast to other external shock scenarios, the efficiency of the shock can be close to unity.

  3. Gamma ray spectrometer for Lunar Scout 2

    Science.gov (United States)

    Moss, C. E.; Burt, W. W.; Edwards, B. C.; Martin, R. A.; Nakano, George H.; Reedy, R. C.

    1993-01-01

    We review the current status of the Los Alamos program to develop a high-resolution gamma-ray spectrometer for the Lunar Scout-II mission, which is the second of two Space Exploration Initiative robotic precursor missions to study the Moon. This instrument will measure gamma rays in the energy range of approximately 0.1 - 10 MeV to determine the composition of the lunar surface. The instrument is a high-purity germanium crystal surrounded by an CsI anticoincidence shield and cooled by a split Stirling cycle cryocooler. It will provide the abundance of many elements over the entire lunar surface.

  4. Nuclear Forensics using Gamma-ray Spectroscopy

    Science.gov (United States)

    Norman, E. B.

    2016-09-01

    Much of George Dracoulis's research career was devoted to utilising gamma-ray spectroscopy in fundamental studies in nuclear physics. This same technology is useful in a wide range of applications in the area of nuclear forensics. Over the last several years, our research group has made use of both high- and low-resolution gamma-ray spectrometers to: identify the first sample of plutonium large enough to be weighed; determine the yield of the Trinity nuclear explosion; measure fission fragment yields as a function of target nucleus and neutron energy; and observe fallout in the U. S. from the Fukushima nuclear reactor accident.

  5. Nuclear forensics using gamma-ray spectroscopy

    CERN Document Server

    Norman, Eric B

    2016-01-01

    Much of George Dracoulis's research career was devoted to utilizing gamma-ray spectroscopy in fundamental studies in nuclear physics. This same technology is useful in a wide range of applications in the area of nuclear forensics. Over the past several years, our research group has made use of both high- and low- resolution gamma ray spectrometers to: identify the first sample of plutonium large enough to be weighed; determine the yield of the Trinity nuclear explosion; measure fission fragment yields as a function of target nucleus and neutron energy; and observe fallout in the U. S. from the Fukushima nuclear reactor accident.

  6. Nuclear Forensics using Gamma-ray Spectroscopy

    Directory of Open Access Journals (Sweden)

    Norman E. B.

    2016-01-01

    Full Text Available Much of George Dracoulis’s research career was devoted to utilising gamma-ray spectroscopy in fundamental studies in nuclear physics. This same technology is useful in a wide range of applications in the area of nuclear forensics. Over the last several years, our research group has made use of both high- and low-resolution gamma-ray spectrometers to: identify the first sample of plutonium large enough to be weighed; determine the yield of the Trinity nuclear explosion; measure fission fragment yields as a function of target nucleus and neutron energy; and observe fallout in the U. S. from the Fukushima nuclear reactor accident.

  7. Status of the Milagro $\\gamma$ Ray Observatory

    CERN Document Server

    Atkins, R; Berley, D; Chen, M L; Coyne, D G; Delay, R S; Dingus, B L; Dorfan, D E; Ellsworth, R W; Evans, D; Falcone, A D; Fleysher, L; Fleysher, R; Gisler, G; Goodman, J A; Haines, T J; Hoffman, C M; Hugenberger, S; Kelley, L A; Leonor, I; Macri, J R; McConnell, M; McCullough, J F; McEnery, J E; Miller, R S; Mincer, A I; Morales, M F; Némethy, P; Ryan, J M; Schneider, M; Shen, B; Shoup, A L; Sinnis, G; Smith, A J; Sullivan, G W; Thompson, T N; Tümer, T O; Wang, K; Wascko, M O; Westerhoff, S; Williams, D A; Yang, T; Yodh, G B

    2001-01-01

    The Milagro Gamma Ray Observatory is the world's first large-area water Cherenkov detector capable of continuously monitoring the sky at TeV energies. Located in northern New Mexico, Milagro will perform an all sky survey of the Northern Hemisphere at energies between ~250 GeV and 50 TeV. With a high duty cycle, large detector area (~5000 square meters), and a wide field-of-view (~1 sr), Milagro is uniquely capable of searching for transient and DC sources of high-energy gamma-ray emission. Milagro has been operating since February, 1999. The current status of the Milagro Observatory and initial results will be discussed.

  8. Supernovae and Gamma Ray Bursts

    Directory of Open Access Journals (Sweden)

    M. Della Valle

    2007-01-01

    Full Text Available Se revisa el estatus observacional de la conexi on Supernova (SN/Estallido de Rayos-Gamma (GRB. Recientes (y no tan recientes observaciones de GRBs largos sugieren que una fracci on signi cativa de ellos (pero no todos est an asociados con supernovas brillantes del tipo Ib/c. Estimaciones actuales de las tasas de producci on de GRBs y SNs dan una raz on para GRB/SNe-Ibc en el rango 0:4%

  9. 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)

  10. The HAWC Gamma-Ray Observatory: Observations of Cosmic 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

    We describe measurements of GeV and TeV cosmic rays with the High-Altitude Water Cherenkov Gamma-Ray Observatory, or HAWC. The measurements include the observation of the shadow of the moon; the observation of small-scale and large-scale angular clustering of the TeV cosmic rays; the prospects for measurement of transient solar events with HAWC; and the observation of Forbush decreases with the HAWC engineering array and HAWC-30.

  11. GammaModeler 3-D gamma-ray imaging technology

    International Nuclear Information System (INIS)

    The 3-D GammaModelertrademark system was used to survey a portion of the facility and provide 3-D visual and radiation representation of contaminated equipment located within the facility. The 3-D GammaModelertrademark system software was used to deconvolve extended sources into a series of point sources, locate the positions of these sources in space and calculate the 30 cm. dose rates for each of these sources. Localization of the sources in three dimensions provides information on source locations interior to the visual objects and provides a better estimate of the source intensities. The three dimensional representation of the objects can be made transparent in order to visualize sources located within the objects. Positional knowledge of all the sources can be used to calculate a map of the radiation in the canyon. The use of 3-D visual and gamma ray information supports improved planning decision-making, and aids in communications with regulators and stakeholders

  12. Study of the action of {sup 60}Co gamma radiation on Salmonella poona, Escherichia coli and Alicyclobacillus acidoterrestris in mango pulp; Estudo da acao da radiacao gama de {sup 60}Co sobre Salmonella poona, Escherichia coli e Alicyclobacillus acidoterrestris em polpa de manga congelada

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Marco Antonio dos Santos

    2009-07-01

    The application of non-thermal treatments has proven effective in inhibiting bacteria such as Salmonella and Escherichia coli. Mango is a fruit of national consumption with a great exportation potential. Meanwhile, outbreaks of food borne disease related to mango consumption caused mistrust on the degree of food security offered by the product. The objective of this work was to establish the radioresistance of bacteria Escherichia coli, Salmonella Poona and Alicyclobacillus acidoterrestris on the mango pulp by the calculation of the D10 values and to know the radiation effect on the sensory characteristics of the fruit pulp. The microbiological profile of frozen mango pulp available at the local market was also established using conventional methods of plating and Most Probable Number (MPN). The pulps experimentally inoculated with the bacteria listed above were irradiated with doses of 0, 1, 2, 3, 4 and 5kGy in a {sup 60}Co source. The sensory analysis was performed using a dose of 5 kGy, using the triangular test and the test of acceptance with hedonic scale. The results of this study show that the quality of mango pulp sell in the local market is not satisfactory in accordance with the standards established by the Brazilian law and the literature, showing the need of using other tools to achieve acceptable levels of quality. The D10 values obtained are in the range of 1.01 and 1.09kGy for E. coli ATCC 8739, 0.60 and 0.98kGy for S. poona and 0.72 e 0.88kGy for A. acidoterrestris respectively. The triangular test showed that a 5kGy radiation dose changed the sensory characteristics of mango pulp. Nevertheless, sensory analysis of a food product prepared with the irradiated pulp obtained good acceptance in the attributes of global appearance, flavor and aroma. (author)

  13. Study of the action of {sup 60}Co gamma radiation on Salmonella poona, Escherichia coli and Alicyclobacillus acidoterrestris in mango pulp;Estudo da acao da radiacao gama de {sup 60}Co sobre Salmonella poona, Escherichia coli and Alicyclobacillus acidoterrestris em polpa de manga congelada

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Marco Antonio dos Santos

    2009-07-01

    The application of non-thermal treatments has proven effective in inhibiting bacteria such as Salmonella and Escherichia coli. Mango is a fruit of national consumption with a great exportation potential. Meanwhile, outbreaks of foodborne disease related to mango consumption caused mistrust on the degree of food security offered by the product. The objective of this work was to establish the radioresistance of bacteria Escherichia coli, Salmonella Poona and Alicyclobacillus acidoterrestris on the mango pulp by the calculation of the D10 values and to know the radiation effect on the sensory characteristics of the fruit pulp. The microbiological profile of frozen mango pulp available at the local market was also established using conventional methods of plating and Most Probable Number (MPN). The pulps experimentally inoculated with the bacteria listed above were irradiated with doses of 0, 1, 2, 3, 4 and 5 kGy in a {sup 60}Co source. The sensory analysis was performed using a dose of 5 kGy, using the triangular test and the test of acceptance with hedonic scale. The results of this study show that the quality of mango pulp sell in the local market is not satisfactory in accordance with the standards established by the Brazilian law and the literature, showing the need of using other tools to achieve acceptable levels of quality. The D10 values obtained are in the range of 1.01 and 1.09 kGy for E. coli ATCC 8739, 0.60 and 0.98 kGy for S. poona and 0.72 and 0.88 kGy for A. acidoterrestris respectively. The triangular test showed that a 5 kGy radiation dose changed the sensory characteristics of mango pulp. Nevertheless, sensory analysis of a food product prepared with the irradiated pulp obtained good acceptance in the attributes of global appearance, flavor and aroma. (author)

  14. Skyshine spectra of gamma rays

    International Nuclear Information System (INIS)

    A study of the spectra of gamma photons back-scattered in vertical direction by infinite air above ground (skyshine) is presented. The source for these measurements is a 650 Ci Cobalt-60 point-source and the skyshine spectra are reported for distances from 150 m to 325 m from the source, measured with a 5 cm x 5 cm NaI(Tl) detector collimated with collimators of 12 mm and 20 mm diameter and 5 cm length. These continuous spectra are unfolded with Gold's iterative technique. The photon-spectra so obtained have a distinct line at 72 keV due to multiply-scattered photons. This is an energy where photoelectric and Compton cross-sections for multiply-scattered photons balance each other. The intensity of the line(I) decreases exponentially with distance (d) from the source obeying a relation of the type I = Isub(o)esup(-μd) where μ is called as ''Multiply-Scatter Coefficient'', a constant of the medium which is air in these measurements. This relationship is explained in terms of a halo around the source comprising of multiply-scattered gamma photons, Isub(0) being the intensity of these scattered photons at the location of cobalt-source. A fraction called as ''Back-scattered Fraction'', the ratio of Isub(0) to the number of original photons from the cobalt-source entering the infinite air, is also calculated. It is shown that with a properly calibrated detector system, this fraction can be used to determine the strength of a large gamma source, viz. a nuclear explosion in air, and for mineral prospecting. These conclusions are general and can be applied to any other infinite medium. Some forward-scatter (transmission) spectra of cobalt-60 source through 10 cm of Pb and 2.5 cm of Al are also reported. (auth.)

  15. Gamma Ray Bursts as Neutrino Sources

    CERN Document Server

    Mészáros, P

    2015-01-01

    Gamma-ray burst sources appear to fulfill all the conditions for being efficient cosmic ray accelerators, and being extremely compact, are also expected to produce multi-GeV to PeV neutrinos. I review the basic model predictions for the expected neutrino fluxes in classical GRBs as well as in low luminosity and choked bursts, discussing the recent IceCube observational constraints and implications from the observed diffuse neutrino flux.

  16. Natural background gamma-ray spectrum. List of gamma-rays ordered in energy from natural radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Ichimiya, Tsutomu [Japan Radioisotope Association, Tokyo (Japan); Narita, Tsutomu; Kitao, Kensuke

    1998-03-01

    A quick index to {gamma}-rays and X-rays from natural radionuclides is presented. In the list, {gamma}-rays are arranged in order of increasing energy. The list also contains {gamma}-rays from radioactive nuclides produced in a germanium detector and its surrounding materials by interaction with cosmic neutrons, as well as direct {gamma}-rays from interaction with the neutrons. Artificial radioactive nuclides emitting {gamma}-rays with same or near energy value as that of the natural {gamma}-rays and X-rays are also listed. In appendix, {gamma}-ray spectra from a rock, uranium ore, thorium, monazite and uraninite and also background spectra obtained with germanium detectors placed in iron or lead shield have been given. The list is designed for use in {gamma}-ray spectroscopy under the conditions of highly natural background, such as in-situ environmental radiation monitoring or low-level activity measurements, with a germanium detector. (author)

  17. Neutron and gamma-ray toxicity studies

    International Nuclear Information System (INIS)

    A kinetic model for radiation-induced life shortening in mice, due to late effects produced by low doses of ionizing radiation, has been developed. The model is based on the concept that an increase in the age-specific force of mortality after exposure to radiation is a consequence of some form or forms of irreversible injury induced by the radiation. Life-shortening responses generated using the model have been shown to be consistent with available data for mice after single or fractionated doses of low- or high-LET radiation. Dose-RBE curves based on life-shortening responses have also been generated. The use of two types of radiation, with quantitative differences in their biological effects, is an integral component of the program: gamma radiation from 60Co sources, and fission neutron radiation from the JANUS reactor. One of the most important differences is the relative lack of dose-rate effects with the latter. Single exposures of neutrons at low doses, down to the lowest dose at which lethal effects or selected physiological changes can be reasonably expected to be observed with a finite number of animals were used. A limited number of experiments with fractionated doses were also carried out to assess the validity of the assumption of dose-rate independence. The problem of gamma radiation emphasized dose protraction and fractionation. There is an extensive body of information available concerning dose-rate effects on life shortening, based largely on duration-of-life exposure. Considerably less is known about protraction and fractionation effects on tumorigenesis

  18. Inactivation effect of 60Co gamma ray on cysticerci of Taenia solium in pork%60Coγ射线对猪肉中囊尾蚴的辐照杀灭效应

    Institute of Scientific and Technical Information of China (English)

    钟凯; 高翔; 计融

    2011-01-01

    Objective revealing the relationship between irradiation dose and inactivation ratio for eysticerei of Taenia solium in pork, determining the minimal dose for totally killing cysticerci and providing scientific evidence for setting up relevant hygienic standards of radiation. Methods After Taenia solium infected pork being treated with different irradiation doses; cysticerci were separated and incubated in fresh swine bile. The adjusted inactivation ratio was calculated according to the survival rate. Results There was a linear correlation between irradiation dose and adjusted inactivation ratio, the D10 value was about 3.8 kGy, and a totally killing could be achieved by 4.5 kGy irradiation. Conclusion Irradiation at a dose of 4.5 kGy could be applied as the maximum dose to inactivate cysticerci of Taenia solium in pork processing.%目的 揭示猪肉中囊尾蚴灭活率与辐照剂量的相关关系及最小杀灭剂量,为制定相应辐照卫生规范提供科学依据.方法 以不同剂量Co γ射线处理感染囊尾蚴的猪肉,并用新鲜猪胆汁孵化剥离出的囊尾蚴,根据成活率计算校正灭活率.结果 辐照剂量与校正灭活率具有线性相关,D值约为3.8 kGy,4.5 kGy可完全杀灭囊尾蚴.结论 4.5 kGy γ射线对猪肉中囊尾蚴有很好的杀灭效果.

  19. Re-estimation of absolute gamma ray intensities of 56Mn using k0- standardization

    Institute of Scientific and Technical Information of China (English)

    M. AHMAD; W. AHMAD; M. U. RAJPUT; A. QAYYUM

    2005-01-01

    The thermal neutron capture gamma ray facility at Pakistan Research Reactor (PARR-1) is being used for the re-estimation of various properties like capture cross-sections, resonance integral, absolute gamma intensities, etc.of different isotopes. The data for gamma ray transitions from the capture of thermal neutrons by 55Mn are not in good agreement specifically below 2 MeV. So there is a need to re-estimate its intensities with better accuracy. Analytical grade MnCl2 powder and high purity Mn metal pieces were used in this study. Standard 152Eu and 60Co radioactive sources as well as thermal neutron capture γ-rays in chlorine were chosen for efficiency calibration. The k0standardization technique was applied for these measurements to eliminate systematic errors in efficiencies. Chlorine also acted as a comparator in k0- factor calculations. The results have been tabulated for the main gamma rays from 56Mn in the low as well as in the medium energy regions. The absolute intensities are in good agreement with most of the reported values.

  20. Interaction studies and gamma-ray properties of some low-Z materials

    Directory of Open Access Journals (Sweden)

    Bhosale Rameshwar R.

    2016-01-01

    Full Text Available In present work we use NaI(Tl detector in narrow-beam good geometry set-up for the gamma ray attenuation studies of some low-Z materials. The parameters such as mass attenuation coefficients, effective atomic numbers and effective electron densities, atomic cross-sections, electronic cross-sections of materials for graphitic powder, polycarbonate, polyvinyl chloride, plaster of Paris, gypsum, and limestone were determined using gamma ray sources 57Co, 133Ba, 137Bs, 60Co, and 22Na at energies of 122, 356, 511, 662, 840, 1170, 1275, and 1330 keV. It was observed that the effective atomic numbers and effective electron densities initially decrease and tend to be almost constant as a function of gamma-ray energy. An attempt was done to check the availability of these low-Z materials at large scales and obtainable at low cost as gamma ray shielding materials. The investigated data are useful in electronic industry, plastic industry, building materials, and agriculture fields.

  1. Mutagenic Effect of UV and 60Coγ Ray on A9 Strain of Arthrospira platensis%紫外线和60Coγ射线对钝顶节旋藻(Arthrospira platensis)的诱变效应

    Institute of Scientific and Technical Information of China (English)

    曹媛媛; 甘旭华; 赵良侠; 夏觅真; 刘广金; 唐欣昀

    2006-01-01

    将对数期的钝顶节旋藻(Arthrospira platensis)(原名钝顶螺旋藻,Spirulina platensis)A9菌株用超声波40 s预处理破碎成2个~4个细胞大小的片断,分别用不同剂量的紫外线(UV)和60Coγ射线处理,诱变后经3小时避光预培养分别接种于液体和固体培养基进行培养.固体培养时UV照射70 s和60Coγ照射3 500 Gy后无菌体存活,而在液体培养中高剂量处理的样品可以部分恢复生长.将诱变后的菌液分别加入20μg·mL-1的ρ-氟苯丙氨酸(ρ-fluorophenylalanine,FPA)和20μg·mL-1的刀豆氨酸(L-canavanine sulphate,CS),放入光照培养箱中预培养3 d~4 d后涂于含相同浓度的氨基酸类似物FPA和CS平板,培养30 d后计算抗氨基酸类似物突变株的突变率.UV对A9菌株的完全致死剂量LD和存活率37%时的剂量D37值分别为70 s和22 s,LD/D37=3.18.A9菌株经UV诱变25 s时存活率为28.7%,抗FPA和抗CS突变率分别为2.31×10-3和1.50×10-3,最大诱变效应比(MME)分别为48.53和52.63.60Coγ射线对A9菌株的LD和D37值分别为3 500 Gy、1 250 Gy,LD/D37=2.8.60Coγ射线显著提高A9菌株的突变率,当诱变剂量为2 000Gy、存活率为10.49%时A9菌株突变率最高,抗FPA和抗CS突变率分别为5.07×10-3和0.964×10-3,最大诱变效应比(MME)分别为241.43和74.15.60Coγ射线对钝顶节旋藻A9菌株的损伤比UV造成的损伤强烈(低的LD/D37值),比UV具有较大的诱变效应(高MME值).采用两种诱变剂获得的抗FPA突变率都要高于抗CS突变率.通过诱变获得了大量的抗氨基酸类似物突变株,为遗传重组研究提供携带重要遗传标记的材料.

  2. The new gamma-ray observatory: CTA

    Science.gov (United States)

    Carr, John

    2016-07-01

    CTA is the next generation gamma-ray observatory and will have a factor 10 better sensitivity compared to existing facilities, as well as many other superior parameters. Aspects of array layout, performance and sites are presented. The broad range of forefront science which will be studied is described.

  3. Gamma-ray emission from nova outbursts

    CERN Document Server

    Hernanz, M

    2013-01-01

    Classical novae produce radioactive nuclei which are emitters of gamma-rays in the MeV range. Some examples are the lines at 478 and 1275 keV (from 7Be and 22Na) and the positron-electron annihilation emission, with the 511 keV line and a continuum. Gamma-ray spectra and light curves are potential unique tools to trace the corresponding isotopes and to give insights on the properties of the expanding envelope. Another possible origin of gamma-rays is the acceleration of particles up to very high energies, so that either neutral pions or inverse Compton processes produce gamma-rays of energies larger than 100 MeV. MeV photons during nova explosions have not been detected yet, although several attempts have been made in the last decades; on the other hand, GeV photons from novae have been detected with the Fermi satellite in V407 Cyg, a nova in a symbiotic binary, where the companion is a red giant with a wind, instead of a main sequence star as in the cataclysmic variables hosting classical novae. Two more nov...

  4. Gamma-ray Novae: Rare or Nearby?

    CERN Document Server

    Morris, Paul J; Brown, Anthony M; Chadwick, Paula M

    2016-01-01

    Classical Novae were revealed as a surprise source of gamma-rays in Fermi LAT observations. During the first 8 years since the LAT was launched, 6 novae in total have been detected to > 5 sigma in gamma-rays, in contrast to the 69 discovered optically in the same period. We attempt to resolve this discrepancy by assuming all novae are gamma-ray emitters, and assigning peak one-day fluxes based on a flat distribution of the known emitters to a simulated population. To determine optical parameters, the spatial distribution and magnitudes of bulge and disc novae in M31 are scaled to the Milky Way, which we approximate as a disc with a 20 kpc radius and elliptical bulge with semi major axis 3 kpc and axis ratios 2:1 in the xy plane. We approximate Galactic reddening using a double exponential disc with vertical and radial scale heights of r_d = 5 kpc and z_d = 0.2 kpc, and demonstrate that even such a rudimentary model can easily reproduce the observed fraction of gamma-ray novae, implying that these apparently r...

  5. Gamma-Ray Telescope and Uncertainty Principle

    Science.gov (United States)

    Shivalingaswamy, T.; Kagali, B. A.

    2012-01-01

    Heisenberg's Uncertainty Principle is one of the important basic principles of quantum mechanics. In most of the books on quantum mechanics, this uncertainty principle is generally illustrated with the help of a gamma ray microscope, wherein neither the image formation criterion nor the lens properties are taken into account. Thus a better…

  6. Primary shutter and gamma ray trap

    International Nuclear Information System (INIS)

    This paper reports on the main radiation shutter and gamma ray trap, which will be used at LNLS front-ends that has been designed. The components external to the UHV chamber have been assembled and are undergoing tests. Vacuum requirements for the chamber have been estimated

  7. Gamma-ray bursts at high redshift

    NARCIS (Netherlands)

    R.A.M.J. Wijers

    1999-01-01

    Gamma-ray bursts are much brighter than supernovae, and could therefore possibly probe the Universe to high redshift. The presently established GRB redshifts range from 0.83 to 5, and quite possibly even beyond that. Since most proposed mechanisms for GRB link them closely to deaths of massive stars

  8. Neutrino Balls and Gamma-Ray Bursts

    CERN Document Server

    Holdom, B

    1994-01-01

    We propose a mechanism by which the neutrino emission from a supernova-type explosion can be converted into a gamma-ray burst of total energy $\\sim 10^{50}$ ergs. This occurs naturally if the explosion is situated inside a ball of trapped neutrinos, which in turn may lie at a galactic core. There are possible unique signatures of this scenario.

  9. Gamma-Gamma Absorption in the Broad Line Region Radiation Fields of Gamma-Ray Blazars

    CERN Document Server

    Boettcher, Markus

    2016-01-01

    The expected level of gamma-gamma absorption in the Broad Line Region (BLR) radiation field of gamma-ray loud Flat Spectrum Radio Quasars (FSRQs)is evaluated as a function of the location of the gamma-ray emission region. This is done self-consistently with parameters inferred from the shape of the spectral energy distribution (SED) in a single-zone leptonic EC-BLR model scenario. We take into account all geometrical effects both in the calculation of the gamma-gamma opacity and the normalization of the BLR radiation energy density. As specific examples, we study the FSRQs 3C279 and PKS 1510-089, keeping the BLR radiation energy density at the location of the emission region fixed at the values inferred from the SED. We confirm previous findings that the optical depth due to $\\gamma\\gamma$ absorption in the BLR radiation field exceeds unity for both 3C279 and PKS 1510-089 for locations of the gamma-ray emission region inside the inner boundary of the BLR. It decreases monotonically, with distance from the cen...

  10. Systematic Study of Gamma-ray bright Blazars with Optical Polarization and Gamma-ray Variability

    CERN Document Server

    Itoh, Ryosuke; Fukazawa, Yasushi; Uemura, Makoto; Tanaka, Yasuyuki T; Kawabata, Koji S; Madejski, Grzegorz M; Schinzel, Frank K; Kanda, Yuka; Shiki, Kensei; Akitaya, Hiroshi; Kawabata, Miho; Moritani, Yuki; Nakaoka, Tatsuya; Ohsugi, Takashi; Sasada, Mahito; Takaki, Katsutoshi; Takata, Koji; Ui, Takahiro; Yamanaka, Masayuki; Yoshida, Michitoshi

    2016-01-01

    Blazars are highly variable active galactic nuclei which emit radiation at all wavelengths from radio to gamma-rays. Polarized radiation from blazars is one key piece of evidence for synchrotron radiation at low energies and it also varies dramatically. The polarization of blazars is of interest for understanding the origin, confinement, and propagation of jets. However, even though numerous measurements have been performed, the mechanisms behind jet creation, composition and variability are still debated. We performed simultaneous gamma-ray and optical photopolarimetry observations of 45 blazars between Jul. 2008 and Dec. 2014 to investigate the mechanisms of variability and search for a basic relation between the several subclasses of blazars. We identify a correlation between the maximum degree of optical linear polarization and the gamma-ray luminosity or the ratio of gamma-ray to optical fluxes. Since the maximum polarization degree depends on the condition of the magnetic field (chaotic or ordered), thi...

  11. Gamma-Ray Bursts: A Mystery Story

    Science.gov (United States)

    Parsons, Ann

    2007-01-01

    With the success of the Swift Gamma-Ray Burst Explorer currently in orbit, this is quite an exciting time in the history of Gamma Ray Bursts (GRBs). The study of GRBs is a modern astronomical mystery story that began over 30 years ago with the serendipitous discovery of these astronomical events by military satellites in the late 1960's. Until the launch of BATSE on the Compton Gamma-ray Observatory, astronomers had no clue whether GRBs originated at the edge of our solar system, in our own Milky Way Galaxy or incredibly far away near the edge of the observable Universe. Data from BATSE proved that GRBs are distributed isotropically on the sky and thus could not be the related to objects in the disk of our Galaxy. Given the intensity of the gamma-ray emission, an extragalactic origin would require an astounding amount of energy. Without sufficient data to decide the issue, a great debate continued about whether GRBs were located in the halo of our own galaxy or were at extragalactic - even cosmological distances. This debate continued until 1997 when the BeppoSAX mission discovered a fading X-ray afterglow signal in the same location as a GRB. This discovery enabled other telescopes, to observe afterglow emission at optical and radio wavelengths and prove that GRBs were at cosmological distances by measuring large redshifts in the optical spectra. Like BeppoSAX Swift, slews to new GRB locations to measure afterglow emission. In addition to improved GRB sensitivity, a significant advantage of Swift over BeppoSAX and other missions is its ability to slew very quickly, allowing x-ray and optical follow-up measurements to be made as early as a minute after the gamma-ray burst trigger rather than the previous 6-8 hour delay. Swift afterglow measurements along with follow-up ground-based observations, and theoretical work have allowed astronomers to identify two plausible scenarios for the creation of a GRB: either through core collapse of super massive stars or

  12. Diagnosing ICF gamma-ray physics

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, Hans W [Los Alamos National Laboratory; Kim, Y H [Los Alamos National Laboratory; Mc Evoy, A [Los Alamos National Laboratory; Young, C S [Los Alamos National Laboratory; Mack, J M [Los Alamos National Laboratory; Hoffman, N [Los Alamos National Laboratory; Wilson, D C [Los Alamos National Laboratory; Langenbrunner, J R [Los Alamos National Laboratory; Evans, S [Los Alamos National Laboratory; Sedillo, T [Los Alamos National Laboratory; Batha, S H [Los Alamos National Laboratory; Dauffy, L [LLNL; Stoeffl, W [LLNL; Malone, R [Los Alamos National Laboratory; Kaufman, M I [Los Alamos National Laboratory; Cox, B C [Los Alamos National Laboratory; Tunnel, T W [Los Alamos National Laboratory; Miller, E K [NSTEC/SB; Ali, Z A [NSREC/LIVERMORE; Horsfield, C J [AWE; Rubery, M [AWE

    2010-01-01

    Gamma rays produced in an ICF environment open up a host of physics opportunities we are just beginning to explore. A branch of the DT fusion reaction, with a branching ratio on the order of 2e-5 {gamma}/n, produces 16.7 MeV {gamma}-rays. These {gamma}-rays provide a direct measure of fusion reaction rate (unlike x-rays) without being compromised by Doppler spreading (unlike neutrons). Reaction-rate history measurements, such as nuclear bang time and burn width, are fundamental quantities that will be used to optimize ignition on the National Ignition Facility (NIF). Gas Cherenkov Detectors (GCD) that convert fusion {gamma}-rays to UV/visible Cherenkov photons for collection by fast optical recording systems established their usefulness in illuminating ICF physics in several experimental campaigns at OMEGA. Demonstrated absolute timing calibrations allow bang time measurements with accuracy better than 30 ps. System impulse response better than 95 ps fwhm have been made possible by the combination of low temporal dispersion GCDs, ultra-fast microchannel-plate photomultiplier tubes (PMT), and high-bandwidth Mach Zehnder fiber optic data links and digitizers, resulting in burn width measurement accuracy better than 10ps. Inherent variable energy-thresholding capability allows use of GCDs as {gamma}-ray spectrometers to explore other interesting nuclear processes. Recent measurements of the 4.44 MeV {sup 12}C(n,n{prime}) {gamma}-rays produced as 14.1 MeV DT fusion neutrons pass through plastic capsules is paving the way for a new CH ablator areal density measurement. Insertion of various neutron target materials near target chamber center (TCC) producing secondary, neutron-induced {gamma}y-rays are being used to study other nuclear interactions and as in-situ sources to calibrate detector response and DT branching ratio. NIF Gamma Reaction History (GRH) diagnostics, based on the GCD concept, are now being developed based on optimization of sensitivity, bandwidth

  13. Perspectives of the GAMMA-400 space observatory for high-energy gamma rays and cosmic rays measurements

    Science.gov (United States)

    Topchiev, N. P.; Galper, A. M.; 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, S.; 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.; 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.; Men'shenin, A. L.; Mikhailov, V. V.; Mocchiutti, E.; Moiseev, A. A.; Mori, N.; Moskalenko, I. V.; Naumov, P. Yu; Papini, P.; 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.; Yurkin, Yu T.; Zampa, N.; Zirakashvili, V. N.; Zverev, V. G.

    2016-02-01

    The GAMMA-400 gamma-ray telescope is intended to measure the fluxes of gamma-rays and cosmic-ray electrons and positrons in the energy range from 100 MeV to several TeV. Such measurements concern the following scientific tasks: investigation of point sources of gamma-rays, studies of the energy spectra of Galactic and extragalactic diffuse emission, studies of gamma-ray bursts and gamma-ray emission from the Sun, as well as high precision measurements of spectra of high-energy electrons and positrons. Also the GAMMA- 400 instrument provides the possibility for protons and nuclei measurements up to knee. But the main goal for the GAMMA-400 mission is to perform a sensitive search for signatures of dark matter particles in high-energy gamma-ray emission. To fulfill these measurements the GAMMA-400 gamma-ray telescope possesses unique physical characteristics in comparison with previous and present experiments. The major advantage of the GAMMA-400 instrument is excellent angular and energy resolution for gamma-rays above 10 GeV. The GAMMA-400 experiment will be installed onboard of the Navigator space platform, manufactured by the NPO Lavochkin Association. The expected orbit will be a highly elliptical orbit (with apogee 300.000 km and perigee 500 km) with 7 days orbital period. An important profit of such an orbit is the fact that the full sky coverage will always be available for gamma ray astronomy.

  14. The future of gamma-ray astronomy

    Science.gov (United States)

    Knödlseder, Jürgen

    2016-06-01

    The field of gamma-ray astronomy has experienced impressive progress over the last decade. Thanks to the advent of a new generation of imaging air Cherenkov telescopes (H.E.S.S., MAGIC, VERITAS) and thanks to the launch of the Fermi-LAT satellite, several thousand gamma-ray sources are known today, revealing an unexpected ubiquity of particle acceleration processes in the Universe. Major scientific challenges are still ahead, such as the identification of the nature of Dark Matter, the discovery and understanding of the sources of cosmic rays, or the comprehension of the particle acceleration processes that are at work in the various objects. This paper presents some of the instruments and mission concepts that will address these challenges over the next decades. xml:lang="fr"

  15. The future of gamma-ray astronomy

    CERN Document Server

    Knödlseder, Jürgen

    2016-01-01

    The field of gamma-ray astronomy has experienced impressive progress over the last decade. Thanks to the advent of a new generation of imaging air Cherenkov telescopes (H.E.S.S., MAGIC, VERITAS) and thanks to the launch of the Fermi-LAT satellite, several thousand gamma-ray sources are known today, revealing an unexpected ubiquity of particle acceleration processes in the Universe. Major scientific challenges are still ahead, such as the identification of the nature of Dark Matter, the discovery and understanding of the sources of cosmic rays, or the comprehension of the particle acceleration processes that are at work in the various objects. This paper presents some of the instruments and mission concepts that will address these challenges over the next decades.

  16. The Future of Gamma Ray Astrophysics

    CERN Document Server

    CERN. Geneva

    2016-01-01

    Over the past decade, gamma ray astrophysics has entered the astrophysical mainstream. Extremely successful space-borne (GeV) and ground-based (TeV) detectors, combined with a multitude of partner telescopes, have revealed a fascinating “astroscape" of active galactic nuclei, pulsars, gamma ray bursts, supernova remnants, binary stars, star-forming galaxies, novae much more, exhibiting major pathways along which large energy releases can flow. From  a basic physics perspective, exquisitely sensitive measurements have constrained the nature of dark matter, the cosmological origin of magnetic field and the properties of black holes. These advances have motivated the development of new facilities, including HAWC, DAMPE, CTA and SVOM, which will further our understanding of the high energy universe. Topics that will receive special attention include merging neutron star binaries, clusters of galaxies, galactic cosmic rays and putative, TeV dark matter.

  17. Interstellar medium structure and content and gamma ray astronomy

    International Nuclear Information System (INIS)

    A general description of gamma-ray astronomy is presented with special emphasis on the study of diffuse gamma-ray emission. This is followed by a collection of reflections and observations on the structure and the gas and dust content of the local interstellar medium. Results of gamma-ray observations on the local interstellar medium are given. The last part is devoted to the whole of the galactic gamma-ray emission and its interpretation

  18. Evaluation of radiological data of some saturated fatty acids using gamma ray spectrometry

    Science.gov (United States)

    Kore, Prashant S.; Pawar, Pravina P.; Palani Selvam, T.

    2016-02-01

    Radiological parameters such as mass attenuation coefficients (μm), total attenuation cross section (σtot), molar extinction coefficient (ε), mass energy absorption coefficient (μen/ρ) and effective electronic cross section (σt, el) of saturated fatty acids, namely butyric acid (C4H8O2), caproic acid (C6H12O2), enanthic acid (C7H14O2), caprylic acid (C8H16O2), pelargonic acid (C9H18O2) and valeric acid (C5H10O2) were measured using NaI(Tl)-based gamma spectrometry. Radioactive sources used in the study are 57Co, 133Ba, 137Cs, 54Mn, 60Co and 22Na. Gamma ray transmission method in a narrow beam good geometry set up was used in the study. The measured data were compared against Win-XCOM-based data. The agreement is within 1%.

  19. 60Co-γ射线辐照处理对天竺葵、观赏椒种子发芽率及幼苗的影响%The Effect of 60Co-γRay Radiation on the Germination Rate of Seed and Growth of Seeding of Pelargonium and Capsioum annuum L.

    Institute of Scientific and Technical Information of China (English)

    强继业; 夏更寿; 王海棠; 尹瑞新; 王元军

    2005-01-01

    60Co-γ射线辐照处理天竺葵、观赏椒种子,观察其发芽率和幼苗生长情况.结果表明:γ射线辐射对这2种观赏植物的发芽率和幼苗生长发育具有不同的影响.对天竺葵的发芽率有促进作用,但抑制幼苗生长;对观赏椒发芽率作用不显著,对幼苗前期生长有抑制作用.

  20. High Energy $\\gamma$ Rays from Ultrahigh Energy Cosmic Ray Protons in $\\gamma$ Ray Bursts

    CERN Document Server

    Böttcher, M

    1998-01-01

    It has recently been proposed that ultrahigh energy ($\\gtrsim 10^{19}$ eV) cosmic rays (UHECR) are accelerated by the blast waves associated with GRBs. We calculate the observed synchrotron radiation spectrum from protons and energetic leptons formed in the cascades initiated by photopion production, taking into account $\\gamma\\gamma$ attenuation at the source. Normalizing to the emission characteristics of GRB~970508, we predict $\\sim 10$ MeV - 100 GeV fluxes at a level which may have been observed with EGRET from bright GRBs, and could be detected with the proposed GLAST experiment or with ground-based air Cherenkov telescopes having thresholds $\\lesssim $ several hundred GeV. Besides testing the UHECR origin hypothesis, the short wavelength emission and afterglows can be used to probe the level of the diffuse intergalactic infrared radiation fields or constrain redshifts of GRB sources.

  1. Material recognition using fission gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Viesti, G. [Dipartimento di Fisica dell' Universita di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy)], E-mail: giuseppe.viesti@pd.infn.it; Sajo-Bohus, L. [Universidad Simon-Bolivar, Laboratorio Fisica Nuclear, Apartado 8900, 1080 A. Caracas (Venezuela, Bolivarian Republic of); Fabris, D. [INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Lunardon, M.; Moretto, S. [Dipartimento di Fisica dell' Universita di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Nebbia, G.; Pesente, S. [INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy)

    2009-07-21

    Material recognition is studied by measuring the transmission spectrum of {sup 252}Cf fission gamma rays in the energy range E{sub {gamma}}=0.1-5.5 MeV for 0.1-MeV-wide energy bins through a number of elementary samples. Each transmitted spectrum is compared with a library of reference spectra for different elements providing the possibility of material identification. In case of elemental samples with known thickness, this procedure allows the identification of the sample Z with uncertainty typically lower than 3 Z-units over a wide range of elements. Applications to composite materials are also reported.

  2. BL Lacertae Objects and the Extragalactic Gamma-Ray Background

    CERN Document Server

    Li, Fan

    2011-01-01

    A tight correlation between gamma-ray and radio emission is found for a sample of BL Lacertae (BL Lac) objects detected by Fermi Gamma-ray Space Telescope (Fermi) and the Energetic Gamma-Ray Experiment Telescope (EGRET). The gamma-ray emission of BL Lac objects exhibits strong variability, and the detection rate of gamma-ray BL Lac objects is low, which may be related to the gamma-ray duty cycle of BL Lac objects. We estimate the gamma-ray duty cycle ~ 0.11, for BL Lac objects detected by EGRET and Fermi. Using the empirical relation of gamma-ray emission with radio emission and the estimated gamma-ray duty cycle, we derive the gamma-ray luminosity function (LF) of BL Lac objects from their radio LF. Our derived gamma-ray LF of BL Lac objects can almost reproduce that calculated with the recently released Fermi bright active galactic nuclei (AGN) sample. We find that about 45% of the extragalactic diffuse gamma-ray background (EGRB) is contributed by BL Lac objects. Combining the estimate of the quasar contri...

  3. Shielding evaluation by laser compton scattering gamma-ray

    International Nuclear Information System (INIS)

    Laser Compton scattering gamma-ray beam was used for evaluation of gamma ray shield. The gamma source of a NewSUBARU Synchrotron Radiation Facility can generate the quasi-monochromatic gamma ray beam of 0.5-1.7 MeV by combining a carbon dioxide laser and a 0.5-1.0 GeV electron beam. This gamma-ray source has small divergence of 1/γ radian due to the relativistic effect, where γ is relativistic factor of electron. Small diameter test beam of gamma-ray of about 1 mm in diameter is possible to use at the 10 m from the gamma-ray source by combining the small divergence gamma-ray beam with small hole lead collimator. Test sample size used was 2 cm in diameter. Measured shield factor was compared with calculated value using known shield materials such as lead. (author)

  4. Gamma-ray pulsars: A gold mine

    Science.gov (United States)

    Grenier, Isabelle A.; Harding, Alice K.

    2015-08-01

    The most energetic neutron stars, powered by their rotation, are capable of producing pulsed radiation from the radio up to γ rays with nearly TeV energies. These pulsars are part of the universe of energetic and powerful particle accelerators, using their uniquely fast rotation and formidable magnetic fields to accelerate particles to ultra-relativistic speed. The extreme properties of these stars provide an excellent testing ground, beyond Earth experience, for nuclear, gravitational, and quantum-electrodynamical physics. A wealth of γ-ray pulsars has recently been discovered with the Fermi Gamma-Ray Space Telescope. The energetic γ rays enable us to probe the magnetospheres of neutron stars and particle acceleration in this exotic environment. We review the latest developments in this field, beginning with a brief overview of the properties and mysteries of rotation-powered pulsars, and then discussing γ-ray observations and magnetospheric models in more detail. xml:lang="fr"

  5. Critical Test Of Gamma Ray Burst Theories

    CERN Document Server

    Dado, Shlomo

    2016-01-01

    Long and precise follow-up measurements of the X-ray afterglow (AG) of very intense gamma ray bursts (GRBs) provide a critical test of GRB afterglow theories. Here we show that the power-law decline with time of X-ray AG of GRB 130427A, the longest measured X-ray AG of an intense GRB with the Swift, Chandra and XMM Newton satellites, and of all other well measured late-time X-ray afterglow of intense GRBs, is that predicted by the cannonball (CB) model of GRBs from their measured spectral index, while it disagrees with that predicted by the widely accepted fireball (FB) models of GRBs.

  6. 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.

  7. X-ray and gamma ray transmission densitometry

    International Nuclear Information System (INIS)

    Gamma and x-ray attenuation densitometers are systems in which measurements of the attenuation of one or several radiation beams are used to infer the density of the attenuating material. This report contains discussions of theoretical and practical aspects of densitometer design, operation, and data interpretation

  8. The Haleakala Gamma Ray Observatory

    International Nuclear Information System (INIS)

    A 10 m2 multi-mirror telescope for observing Cherenkov light signals from atmospheric cascades is now operating at Mount Haleakala, Maui, Hawaii. It differs from other atmospheric Cherenkov detectors in accepting pulses that originate from single photoelectrons, employing two sets of 18 optically independent phototubes in a logic system with nanosecond time resolution to reject ambient light from the night sky. With an angular aperture of 1.3x10-4 sr, cosmic ray showers are observed at a rate of ≅ 0.5 hz at the zenith, with nearly complete rejection of ambient light. This rate for hadronic showers implies an effective threshold near 100 GeV for electromagnetic showers. Two regions of the sky, one centered on the source and the other separated by from it by 3.60 are simultaneously monitored. Examples of observations of episodic and periodic (pulsar) sources are given. (orig.)

  9. Gamma-Ray Library and Uncertainty Analysis: Passively Emitted Gamma Rays Used in Safeguards Technology

    Energy Technology Data Exchange (ETDEWEB)

    Parker, W

    2009-09-18

    Non-destructive gamma-ray analysis is a fundamental part of nuclear safeguards, including nuclear energy safeguards technology. Developing safeguards capabilities for nuclear energy will certainly benefit from the advanced use of gamma-ray spectroscopy as well as the ability to model various reactor scenarios. There is currently a wide variety of nuclear data that could be used in computer modeling and gamma-ray spectroscopy analysis. The data can be discrepant (with varying uncertainties), and it may difficult for a modeler or software developer to determine the best nuclear data set for a particular situation. To use gamma-ray spectroscopy to determine the relative isotopic composition of nuclear materials, the gamma-ray energies and the branching ratios or intensities of the gamma-rays emitted from the nuclides in the material must be well known. A variety of computer simulation codes will be used during the development of the nuclear energy safeguards, and, to compare the results of various codes, it will be essential to have all the {gamma}-ray libraries agree. Assessing our nuclear data needs allows us to create a prioritized list of desired measurements, and provides uncertainties for energies and especially for branching intensities. Of interest are actinides, fission products, and activation products, and most particularly mixtures of all of these radioactive isotopes, including mixtures of actinides and other products. Recent work includes the development of new detectors with increased energy resolution, and studies of gamma-rays and their lines used in simulation codes. Because new detectors are being developed, there is an increased need for well known nuclear data for radioactive isotopes of some elements. Safeguards technology should take advantage of all types of gamma-ray detectors, including new super cooled detectors, germanium detectors and cadmium zinc telluride detectors. Mixed isotopes, particularly mixed actinides found in nuclear reactor

  10. Humoral immune response against native or 60Co irradiated venom and mucus from stingray Paratrygon aiereba

    International Nuclear Information System (INIS)

    Poisonings and traumas caused by poisonous freshwater fish such as rays are considered a major public health problem and draw attention because of accidents involving these animals cause serious local symptoms and are disabling, keeping the victim away from work. The therapy of these cases is based only on the symptoms of patients, which implies in its low efficiency, causing suffering for the victims. This study aims to evaluate and compare the humoral immune response in animals inoculated with native or 60Co irradiated Paratrygon aiereba venom and mucus. Ionizing radiation has proven to be an excellent tool to decrease the toxicity of venoms and isolated toxins. The mucus and venom samples of P. aiereba were irradiated using gamma rays from a 60Co source. Animals models were immunized with the native or irradiated mucus or venom. The assays were conducted to assess the production of antibodies by the immunized animals using enzyme immunoassay and western blotting. Preliminary results show the production of antibodies by the immunized animals. The resulting sera were also checked for antigenic cross- reactivity between venom and mucus, demonstrating the potential of mucus as an antigen for serum production for the specific treatment for accidents by stingrays. However, it is essential to carry out further tests in order to verify the neutralization of the toxin by antibodies formed by animals. (author)

  11. Fermi Gamma-ray Space Telescope Observations of Gamma-ray Pulsars

    CERN Document Server

    Parkinson, P M Saz

    2009-01-01

    The Large Area Telescope on the recently launched Fermi Gamma-ray Space Telescope (formerly GLAST), with its large field of view and effective area, combined with its excellent timing capabilities, is poised to revolutionize the field of gamma-ray astrophysics. The large improvement in sensitivity over EGRET is expected to result in the discovery of many new gamma-ray pulsars, which in turn should lead to fundamental advances in our understanding of pulsar physics and the role of neutron stars in the Galaxy. Almost immediately after launch, Fermi clearly detected all previously known gamma-ray pulsars and is producing high precision results on these. An extensive radio and X-ray timing campaign of known (primarily radio) pulsars is being carried out in order to facilitate the discovery of new gamma-ray pulsars. In addition, a highly efficient time-differencing technique is being used to conduct blind searches for radio-quiet pulsars, which has already resulted in new discoveries. I present some recent results...

  12. Determination of gamma ray attenuation coefficients of Al–4% Cu/B4C metal matrix composites at 662, 1173 and 1332 keV

    Indian Academy of Sciences (India)

    I Akkurt; K Günoğlu; A Çalik; M S Karakas

    2014-08-01

    Gamma ray attenuation coefficients of metal matrix composites have been investigated. For this purpose, the linear attenuation coefficients of composites containing boron carbide (B4C) at different rates have been measured using a gamma spectrometer that contains a NaI(Tl) detector and MCA at 662, 1173 and 1332 keV, which are obtained from 137Cs and 60Co sources. The measured results were compared with the calculation obtained using computer code of XCOM for 1 keV–1 GeV gamma energies.

  13. Physics of gamma-ray bursts

    Science.gov (United States)

    Lamb, D. Q.

    1984-01-01

    Attention is given to the accumulating evidence for the view that gamma-ray bursts come from strongly magnetic neutron stars, discussing the physical properties of the emission region and the radiation processes expected in strong magnetic fields, and emphasizing that the observed burst spectra require that the emission region be optically thin. This entails that the energy of the emitting plasma and/or the plasma itself be continuously replenished during a burst, and that the cooling time scale of the emitting plasma be much shorter than the observed duration of the bursts. This characteristic of the cooling time scale implies that the burst intensity and spectrum can vary on extremely short time scales, and that the burst duration must have a separate explanation. It is emphasized that synchrotron emission is favored as the gamma-ray production mechanism; it is the only mechanism capable of satisfying the optical thinness constraint while producing the observed luminosity.

  14. TeV Gamma Ray Astronomy

    CERN Document Server

    Cui, Wei

    2009-01-01

    The field of ground-based gamma ray astronomy has enjoyed rapid growth in recent years. As an increasing number of sources are detected at TeV energies, the field has matured and become a viable branch of modern astronomy. Lying at the uppermost end of the electromagnetic rainbow, TeV photons are always preciously few in number but carry essential information about the particle acceleration and radiative processes involved in extreme astronomical settings. Together with observations at longer wavelengths, TeV gamma-ray observations have drastically improved our view of the universe. In this review, we briefly describe recent progress in the field. We will conclude by providing a personal perspective on the future of the field, in particular, on the significant roles that China could play to advance this young but exciting field.

  15. Gamma-ray Constraints on Effective Interactions

    CERN Document Server

    Cheung, Kingman; Yuan, Tzu-Chiang

    2011-01-01

    Using an effective interaction approach to describe the interactions between the dark matter particle and the light degrees of freedom of the standard model, we calculate the gamma-ray flux due to the annihilation of the dark matter into quarks, followed by fragmentation into neutral pions which subsequently decay into photons. By comparison to the mid-latitude data released from the Fermi-LAT experiment, we obtain useful constraints on the size of the effective interactions and they are found to be comparable to those deduced from collider, gamma-ray line and anti-matter search experiments. However, the two operators induced by scalar and vector exchange among fermionic dark matter and light quarks that contribute to spin-independent cross sections are constrained more stringently by the recent XENON100 data.

  16. Stellar Photon Archaeology with Gamma-Rays

    Science.gov (United States)

    Stecker, Floyd W.

    2009-01-01

    Ongoing deep surveys of galaxy luminosity distribution functions, spectral energy distributions and backwards evolution models of star formation rates can be used to calculate the past history of intergalactic photon densities and, from them, the present and past optical depth of the Universe to gamma-rays from pair production interactions with these photons. The energy-redshift dependence of the optical depth of the Universe to gamma-rays has become known as the Fazio-Stecker relation (Fazio & Stecker 1970). Stecker, Malkan & Scully have calculated the densities of intergalactic background light (IBL) photons of energies from 0.03 eV to the Lyman limit at 13.6 eV and for 0$ photon densities in the past, i.e., the "archaeo-IBL.", and therefore allow a better measure of the past history of the total star formation rate, including that from galaxies too faint to be observed.

  17. Real time gamma-ray signature identifier

    Science.gov (United States)

    Rowland, Mark; Gosnell, Tom B.; Ham, Cheryl; Perkins, Dwight; Wong, James

    2012-05-15

    A real time gamma-ray signature/source identification method and system using principal components analysis (PCA) for transforming and substantially reducing one or more comprehensive spectral libraries of nuclear materials types and configurations into a corresponding concise representation/signature(s) representing and indexing each individual predetermined spectrum in principal component (PC) space, wherein an unknown gamma-ray signature may be compared against the representative signature to find a match or at least characterize the unknown signature from among all the entries in the library with a single regression or simple projection into the PC space, so as to substantially reduce processing time and computing resources and enable real-time characterization and/or identification.

  18. Are gamma-ray bursts cosmological?

    CERN Document Server

    Horvath, I

    2015-01-01

    Gamma-ray burst sources are distributed with a high level of isotropy, which is compatible with either a cosmological origin or an extended Galactic halo origin. The brightness distribution is another indicator used to characterize the spatial distribution in distance. In this paper the author discusses detailed fits of the BATSE gamma-ray burst peak-flux distributions with Friedmann models taking into account possible density evolution and standard candle luminosity functions. A chi-square analysis is used to estimate the goodness of the fits and the author derives the significance level of limits on the density evolution and luminosity function parameters. Cosmological models provide a good fit over a range of parameter space which is physically reasonable

  19. TeV gamma-ray astronomy

    Institute of Scientific and Technical Information of China (English)

    Wei Cui

    2009-01-01

    The field of ground-based gamma-ray astronomy has enjoyed rapid growth in recent years. As an increasing number of sources are detected at TeV energies, the field has matured and become a viable branch of modern astronomy. Lying at the uppermost end of the electromagnetic rainbow, TeV photons are always preciously few in number but carry essential information about the particle acceleration and radiative processes involved in extreme astronomical settings. Together with observations at longer wavelengths, TeV gamma-ray observations have drastically improved our view of the universe. In this re-view, we briefly describe recent progress in the field. We will conclude by providing a personal perspective on the future of the field, in particular, on the significant roles that China could play in advancing this young but exciting field.

  20. Environmental Effects of Gamma Ray Bursts

    International Nuclear Information System (INIS)

    Gamma rays bursts, coming from very massive stars, are the most powerful explosions in our Universe. Some authors have linked them to some of the climatic changes and consequent biological mass extinctions of the Phanerozoic eon. However, the consequences of their direct impact on primitive Earth, is today a hot topic of debate. On the other hand, it is usually assumed that they were more common in earlier stages of our galaxy. So it is important to evaluate its potential effects on terrestrial paleoenvironments. We outline some simple models to estimate their influence mainly on the primordial atmospheric chemistry of Earth and on the climate in general. To do that, we consider different scenarios where the atmospheric composition diverges substantially from the atmosphere today, and compute the evolution of principal chemical species under the intense radiational stress of a gamma ray burst. Furthermore, the possible impact on the isotopic composition, geochemistry and the biosphere are mentioned in general way

  1. Gamma Ray Bursts Observations and Theoretical Conjectures

    CERN Document Server

    Alagoz, E; Carrillo, C; Golup, G T; Grimes, M; Herrera, Mora C; Gallo, Palomino J L; López, Vega A; Wicht, J

    2008-01-01

    Gamma Ray Bursts (GRBs) are short bursts of very high energy photons which were discovered in the late 1960s. Ever since their discovery, scientists have wondered about their origin. Nowadays it is known that they originate outside the Milky Way because of their high red shift rst measured in the afterglows thanks to the Beppo-SAX satellite and ground-based observations. However, theoreticians still do not agree about the mechanism that generates the bursts, and different competing models are animatedly debated. Current GRB experiments include the Swift satellite and the Pierre Auger Observatory that could detect GRBs with an increase of the background. A forthcoming dedicated experiment is GLAST, a satellite observatory for detecting gamma rays with energies up to 300 GeV, whose launch is scheduled for early 2008.

  2. 60Co-γ射线对彩色马蹄莲Parfait的辐照效应及其在高温高湿胁迫下的生理响应%Effects of 60 CoRay Radiation on Color Lily ‘ Parfait' and Their Physiological Responses to High Temperature and Humidity

    Institute of Scientific and Technical Information of China (English)

    陆波; 郑玉红; 陈默; 彭峰; 束晓春; 高风

    2014-01-01

    为了研究物理射线辐射对彩色马蹄莲外部性状和生理特性的影响,分别采用20、40、60和80 Gy的60Co-γ射线对彩色马蹄莲Parfait丛生芽进行辐照.结果表明,除80Gy辐射的丛生芽全部死亡外,其余剂量辐射处理后的组培苗叶形指数和株高呈逐渐降低的趋势,增殖系数逐渐增加,且呈现出剂量效应,但辐射对叶片叶绿素总量影响不大;对诱导苗进行温室越夏高温栽培,发现对照及3个剂量辐射处理的幼苗成活率分别为38.54%、19.10%、56.77%和41.27%;在模拟高温高湿条件下,辐射处理后组培苗的SOD和CAT和活力及MDA的含量在6h时达到峰值,之后逐渐下降,且各处理大都高于对照;40Gy处理的各项指标变化幅度最大,这与其较高的越夏存活率相吻合.以上结果表明60、40Gy的剂量分别为诱导彩色马蹄莲形态和抗性变异较为适宜的剂量,同时也说明60 Co-γ射线辐射可以作为培育彩色马蹄莲新品种的一种有效途径.

  3. Solar gamma-ray lines and interplanetary solar protons

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimori, M.

    1985-12-01

    Solar gamma-ray lines and protons were simultaneously observed for six flares on 1 April, 4 April, 27 April, 13 May 1981, 1 February, and 6 June, 1982 by Hinotori and Himawari satellites. The time histories of gamma-ray lines and protons are analyzed. The relationship between the gamma-ray line fluences and peak proton fluxes for these flares does not reveal an apparent correlation between them. The present result implies that the protons producing gamma-ray lines in the flare region and protons observed near the earth do not always belong to the same population, and favor the downward streaming model for the gamma-ray line production.

  4. Sorption of 60 Co on inorganic solids

    International Nuclear Information System (INIS)

    The behavior of sorption of the 60 Co in aqueous solution under static conditions to different values of pH of the aqueous solution (1, 3, 5, 7, and 10) on MgO, MnO2, SnO, TiO2, activated carbon and calcinate hydrotalcite was investigated. It was found that the best sorbents of the 60 Co was the MnO2, activated carbon and TiO2 whose sorption was incremented when increasing the pH value of the aqueous solutions, in the one case of the hydrated oxides, the 60 Co interacted with the electrically charged surface of the sorbents that depends on the pH of the solution and of the point of zero charge (zpc) of the sorbent. (Author)

  5. GAMMA-RAY BURSTS, NEW COSMOLOGICAL BEACONS

    Directory of Open Access Journals (Sweden)

    V. Avila-Reese

    2009-01-01

    Full Text Available Long Gamma-Ray Bursts (GRBs are the brightest electromagnetic explosions in the Universe, associated to the death of massive stars. As such, GRBs are potential tracers of the evolution of the cosmic massive star formation, metallicity, and Initial Mass Function. GRBs also proved to be appealing cosmological distance indicators. This opens a unique opportunity to constrain the cosmic expansion history up to redshifts 5-6. A brief review on both subjects is presented here.

  6. Are Gamma-Ray Bursts Standard Candles?

    OpenAIRE

    Li, Li-Xin

    2007-01-01

    By dividing a sample of 48 long-duration gamma-ray bursts (GRBs) into four groups with redshift from low to high and fitting each group with the Amati relation log Eiso = a + b log Epeak, I find that parameters a and b vary with the mean redshift of the GRBs in each group systematically and significantly. The results suggest that GRBs evolve strongly with the cosmic redshift and hence are not standard candles.

  7. Solution To The Gamma Ray Burst Mystery?

    OpenAIRE

    Shaviv, Nir J.; Dar, Arnon

    1996-01-01

    Photoexcitation and ionization of partially ionized heavy atoms in highly relativistic flows by interstellar photons, followed by their reemission in radiative recombination and decay, boost star-light into beamed $\\gamma$ rays along the flow direction. Repeated excitation/decay of highly relativistic baryonic ejecta from merger or accretion induced collapse of neutron stars in dense stellar regions (DSRs), like galactic cores, globular clusters and super star-clusters, can convert enough kin...

  8. Gamma Ray Bursts and their Optical Counterparts

    International Nuclear Information System (INIS)

    Gamma Ray Bursts (GRB) have been discovered 38 years ago and still remain one of the most intriguing puzzles of astrophysics. In this paper we remind briefly the history of GRB studies and review the current experimental evidence with the emphasis on GRB optical counterparts. At the end we introduce '' π of the Sky '' project designed to catch prompt optical emission from GRB sources. (author)

  9. Cosmological parametrization of $\\gamma$ ray burst models

    CERN Document Server

    Linder, E V

    1996-01-01

    Using three parametrizations of the gamma ray burst count data comparison is made to cosmological source models. While simple models can fit and faint end slope constraints, the addition of a logarithmic count range variable describing the curvature of the counts shows that models with no evolution or evolution power law in redshift with index less than 10 fail to satisfy simultaneously all three descriptors of the burst data. The cosmological source density that would be required for a fit is illustrated.

  10. Gamma-ray bursts - a critical review

    International Nuclear Information System (INIS)

    We present a short general introduction into the field of gamma-ray bursts (GRBs) research, summarizing the past and the present status. We give an general view of the GRBs observations to date, both in the prompt emission phase as well as in the afterglow phase, and a brief primer into the theory, mainly in the frame-work of the fireball model. (authors)

  11. Very high energy gamma ray astrophysics

    International Nuclear Information System (INIS)

    The Whipple Observatory's atmospheric Cerenkov camera has detected TeV radiation from four galactic sources: the Crab Nebula, Cygnus X-3, Hercules X-1, and 4U0115+63. Recent simulations encourage the view that unwanted cosmic-ray background showers may be suppressed by a large factor. Emphasis in the coming year will be on determining optimum selection criteria for enhancing gamma-ray signals and in developing a prototype camera with finer angular resolution as a first step towards implementation of the HERCULES concept

  12. EXIST's Gamma-Ray Burst Sensitivity

    OpenAIRE

    Band, D. L.; Grindlay, J. E.; Hong, J.; Fishman, G.; Hartmann, D. H.; Garson III, A.; Krawczynski, H.; Barthelmy, S.; Gehrels, N.; Skinner, G.

    2007-01-01

    We use semi-analytic techniques to evaluate the burst sensitivity of designs for the EXIST hard X-ray survey mission. Applying these techniques to the mission design proposed for the Beyond Einstein program, we find that with its very large field-of-view and faint gamma-ray burst detection threshold, EXIST will detect and localize approximately two bursts per day, a large fraction of which may be at high redshift. We estimate that EXIST's maximum sensitivity will be ~4 times greater than that...

  13. Description of morphologic characters in avocado trees (Persea americana. Mill) var. Hass, submitted to gamma radiation of {sup 60} Co; Descripcion de caracteres morfologicos en arboles de aguacate (Persea americana. Mill) var. Hass, sometidos a radiacion gama de {sup 60} Co

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval R, L

    2004-07-01

    It was carried out the characterization of 77 trees of avocado ''Hass'' subjected to gamma radiation of Co{sup 60}, in doses of 0, 5, 10,15, 20 and 25 Gy based on previous studies of radiosensitivity with ends of improvement located in the experimental center ''La Labor'' belonging to the foundation Salvador Sanchez Colin. CICTAMEX. S C. in Temascaltepec, Mexico. It was carried out the morphological characterization of this variety according to the nomenclature settled down by the International Office of Genetic Resources (IBPGRI), registering 27 variables for the description of the tree, 33 for description of the fruit and 14 for the characterization of the seed. Regarding the architectural characterization 10 variables were evaluated. Using gamma radiation of Co{sup 60} in the doses of 15 and 20 Gy it was detected a reduction of 22% in the portage of the tree, likewise had reduction the diameter of the trunk and of the foliage. It was found that the reduction in the behavior of the tree induces to a bigger variation of the form of the same one, in the distribution of the branches in the form of the fruit and in the form of the seed you Also detects a remarkable increment in the productivity of some hoist irradiated regarding the architecture of the tree one observes that the angle of inclination of the branches increase when being increased the radiation dose and that the longitude of the annual section of growth decreased significantly in the doses of 20 and 25 Gy. One observes a significant Increment in the I number of buds prolepticos in those hoist irradiated in the I finish mbdulo of rhythmic growth. Io that indicates a change substantial in the I inhabit of growth With the purpose of determining if the changes in morphology and architecture of the tree corresponded with the modification at level meristematico, they were carried out observations to the court microscope of having knitted apical vegetative meristematico

  14. Gamma Rays frim the Galactic Centre

    CERN Document Server

    Erlykin, A D

    2007-01-01

    Recent results from the HESS gamma ray telescope have shown the presence of both a diffuse, extended, flux of gamma rays above ~0.4 TeV and discrete sources in and near the Galactic Centre. Here, we put forward a possible explanation in terms of the diffusion of cosmic ray protons from a succession of supernova remnants (SNR) in the SgrA* region of the Galaxy plus a contribution from SNR in the rest of the Galactic Centre Region, to be called the Galactic Centre Ridge (GCR). Protons are favoured over electrons because the mG magnetic fields in the Region will attenuate energetic electrons severely. Prominent features are the need for 'anomalous diffusion' of the protons in the whole region and the adoption of low efficiency for SNR acceleration in the high density regions. The latter is related by us to the well-known low 'cosmic ray gradient' in the Galaxy. A corroborating feature is the close correlation of inferred cosmic ray intensity with the smoothed intensity of 5 GHZ radio radiation. We attribute this...

  15. Gamma Ray Bursts Cook Book I: Formulation

    CERN Document Server

    Ziaeepour, Houri

    2008-01-01

    Since the suggestion of relativistic shocks as the origin of gamma-ray bursts (GRBs) in early 90's, the mathematical formulation of this process has stayed at phenomenological level. One of the reasons for the slow development of theoretical works in this domain has been the simple power-law behaviour of the afterglows hours or days after the prompt gamma-ray emission. Nowadays with the launch of the Swift satellite, gamma-ray bursts can be observed in multi-wavelength from a few tens of seconds after trigger onward. These observations have leaded to the discovery of features unexplainable by the simple formulation of the shocks and emission processes used up to now. But "devil is in details" and some of these features may be explained with a more detailed formulation of phenomena and without adhoc addition of new processes. Such a formulation is the goal of this work. We present a consistent formulation of the collision between two spherical relativistic shells. The model can be applied to both internal and ...

  16. Distribution of Gamma-Ray Bursts

    Science.gov (United States)

    Diaz Rodriguez, Mariangelly; Smith, M.; Tešic, G.

    2014-01-01

    Gamma-Ray Bursts (GRBs) are known to be bright, irregular flashes of gamma rays that typically last just a few seconds, believed to be caused by stellar collapse or the merger of a pair of compact objects. Through previous work, it has been found that GRBs are distributed roughly uniformly over the entire sky, rather than being confined to the relatively narrow band of the Milky Way. Using the Python programming language, we generated a model of GRBs over cosmological distances, based on current empirical GRB distributions. The grbsim python module uses the acceptance-rejection Monte Carlo method to simulate the luminosity and redshift of a large population of GRBs, including cosmological effects such as dark energy and dark matter terms that modify the large-scale structure of space-time. The results of running grbsim are demonstrated to match the distribution of GRBs observed by the Burst Alert Telescope on NASA’s Swift satellite. The grbsim module will subsequently be used to simulate gamma ray and neutrino events for the Astrophysical Multimessenger Observatory Network.

  17. Gamma-ray astronomy with underground detectors

    CERN Document Server

    Halzen, Francis

    1995-01-01

    Underground detectors measure the directions of up-coming muons of neutrino origin. They can also observe down-going muons made by gamma rays in the Earth's atmosphere. Although gamma ray showers are muon-poor, they produce a sufficient number of muons to detect the sources observed by GeV and TeV telescopes. With a threshold higher by one hundred and a probability of muon production of about 1\\% for the shallower AMANDA and Lake Baikal detectors, these instruments can, for a typical GRO source, match the detection efficiency of a GeV satellite detector since their effective area is larger by a factor 10^4. The muons must have enough energy for accurate reconstruction of their direction. Very energetic muons on the other hand are rare because they are only produced by higher energy gamma rays whose flux is suppressed by the decreasing flux at the source and by absorption on interstellar light. We show that there is a window of opportunity for muon astronomy in the 100~GeV energy region which nicely matches th...

  18. Gamma ray tracking with the AGATA demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    Birkenbach, Benedikt; Hess, Herbert; Lewandowski, Lars; Reiter, Peter; Steinbach, Tim; Schneiders, David; Vogt, Andreas [IKP, Universitaet zu Koeln (Germany); Collaboration: AGATA-Collaboration

    2014-07-01

    The performance of the AGATA demonstrator will be discussed based on data taken from a multi-nucleon transfer experiment at the AGATA PRISMA setup at LNL (INFN, Italy). A primary {sup 136}Xe beam of 1 GeV hitting a {sup 238}U target was used to produce a multitude of nuclei in the vicinity of {sup 136}Xe and corresponding reaction partners in the actinide region. The obtained results for in-beam gamma-ray spectroscopy allow for a critical assessment of the novel gamma ray tracking technique and comparison with standard procedure. High resolution spectroscopy of both reaction products after multi-nucleon transfer reaction in the presence of a high background from excited fission fragments is based on pulse-shape analysis (PSA) and gamma-ray tracking (GRT). The quality of the position information is crucial for the final energy resolution after Doppler correction. The impact of the calculated PSA libraries and the initial detector characterization for the PSA and GRT are summarized. Details of the achieved position and energy resolution, peak-to-background optimization are presented and illustrated with results from the neutron-transfer products in Xe and U-isotopes.

  19. Study of p-wave gamma-ray strength functions

    International Nuclear Information System (INIS)

    Gamma-ray strength functions are important for description of the gamma emission channel in nuclear reactions. The impact of different models- Weisskopf's single particle model, Brink's standard Lorentzian and Kopecky's generalized Lorentzian for gamma ray strength functions on the calculation of neutron capture related experimental quantities such as total radiation widths Γγ cross sections and gamma-ray spectra has been studied

  20. 60Co-γ射线辐射对美女樱·菠萝菊根长·芽长及出芽率的影响%Effect of the Treatment with 60CoRay Irradiation on the Germination Rate and the Length of Bud and Root of Verbena hortensis and Carthamus tinctorius

    Institute of Scientific and Technical Information of China (English)

    吴光升; 强继业; 陈立

    2005-01-01

    对美女樱和菠萝菊种子进行4种剂量的60Co-γ射线处理,结果显示:40Gy的辐射剂量可促进美女樱出芽率,而10、20、80Gy的辐射剂量抑制出芽率.辐射剂量和芽长、根长呈正相关.80Gy辐射剂量对美女樱的出芽率、芽长、根长较适宜.对菠萝菊而言,辐射剂量和出芽率、根长呈负相关.辐照对菠萝菊种子起抑制作用,说明菠萝菊不适合此范围的高剂量辐照.其中辐射剂量为20、80Gy时,菠萝菊种子不发芽;辐射剂量为40 Gy时,芽长达到了4.91 mm,远远大于对照0.57 mm.

  1. The solar gamma ray and neutron capabilities of COMPTEL on the Gamma Ray Observatory

    Science.gov (United States)

    Ryan, James M.; Lockwood, John A.

    1989-01-01

    The imaging Compton telescope COMPTEL on the Gamma Ray Observatory (GRO) has unusual spectroscopic capabilities for measuring solar gamma-ray and neutron emission. The launch of the GRO is scheduled for June 1990 near the peak of the sunspot cycle. With a 30 to 40 percent probability for the Sun being in the COMPTEL field-of-view during the sunlit part of an orbit, a large number of flares will be observed above the 800 keV gamma-ray threshold of the telescope. The telescope energy range extends to 30 MeV with high time resolution burst spectra available from 0.1 to 10 MeV. Strong Compton tail suppression of instrumental gamma-ray interactions will facilitate improved spectral analysis of solar flare emissions. In addition, the high signal to noise ratio for neutron detection and measurement will provide new neutron spectroscopic capabilities. Specifically, a flare similar to that of 3 June 1982 will provide spectroscopic data on greater than 1500 individual neutrons, enough to construct an unambiguous spectrum in the energy range of 20 to 200 MeV. Details of the instrument and its response to solar gamma-rays and neutrons will be presented.

  2. The Swift Gamma-Ray Burst Mission

    CERN Document Server

    Gehrels, N; Burrows, D N; Chincarini, G L; Cominsky, L R; Giommi, P; Hurley, K C; Marshall, F E; Mason, K O; Mészáros, P; Nousek, J A; Roming, P W A; Wells, A A; White, N E; Team, Swift Science

    2004-01-01

    The Swift mission, scheduled for launch in early 2004, is a multiwavelength observatory for gamma-ray burst (GRB) astronomy. It is the first-of-its-kind autonomous rapid-slewing satellite for transient astronomy and pioneers the way for future rapid-reaction and multiwavelength missions. It will be far more powerful than any previous GRB mission, observing more than 100 bursts per year and performing detailed X-ray and UV/optical afterglow observations spanning timescales from 1 minute to several days after the burst. The objectives are to determine the origin of GRBs; classify GRBs and search for new types; study the interaction of the ultra-relativistic outflows of GRBs with their surrounding medium; and use GRBs to study the early universe out to z>10. The mission is being developed by a NASA-led international collaboration. It will carry three instruments: a new-generation wide-field gamma-ray (15-150 keV) detector; a narrow-field X-ray telescope; and a narrow-field UV/optical telescope. Redshift determin...

  3. Is Calvera a Gamma-ray Pulsar?

    CERN Document Server

    Halpern, J P

    2011-01-01

    Originally selected as a neutron star (NS) candidate in the ROSAT All-Sky Survey, 1RXS J141256.0+792204 ("Calvera") was discovered to be a 59 ms X-ray pulsar in a pair of XMM-Newton observations (Zane et al. 2011). Surprisingly, their claimed detection of this pulsar in Fermi gamma-ray data requires no period derivative, severely restricting its dipole magnetic field strength, spin-down luminosity, and distance to small values. This implies that the cooling age of Calvera is much younger than its characteristic spin-down age. If so, it could be a mildly recycled pulsar, or the first "orphaned" central compact object (CCO). Here we show that the published Fermi ephemeris fails to align the pulse phases of the two X-ray observations with each other, which indicates that the Fermi detection is almost certainly spurious. Analysis of additional Fermi data also does not confirm the gamma-ray detection. This leaves the spin-down rate of Calvera less constrained, and its place among the families of NSs uncertain. It ...

  4. Effect of Different Polar Parts Extracted from Mucuna Birdwoodiana Tutcher on Peripheral Blood Counts of 60Coγray Irradiated Mice%白花油麻藤不同极性部位对60Coγ射线辐射小鼠外周血象的保护作用

    Institute of Scientific and Technical Information of China (English)

    王东晓; 陈若芸; 刘屏; 巩婷; 陈桂芸; 于腾飞; 马晓菲

    2008-01-01

    目的 观察白花油麻藤不同极性部位对骨髓抑制小鼠外周血象的影响,初步明确其促进造血的有效活性部位.方法 60 Coγ射线亚致死量辐射造成骨髓抑制小鼠模型,灌胃给予白花油麻藤各部位药液,于给药后1、3、7、14、21、28d检测其外周血白细胞(WBC)、红细胞(RBC)、血红蛋白(HGB)、血小板(PLT).结果 辐射后小鼠外周血WBC、RBC、HGB、PLT较正常组明显下降,给予白花油麻藤各部位治疗后,其下降趋势减缓,与模型组比较,白花油麻藤95%部分和水部分可显著促进辐射小鼠外周血WBC、RBC、HGB、PLT的恢复(P<0.05).结论 白花油麻藤50%乙醇提取物的95%洗脱部分和水洗脱部分可明显促进辐射所致骨髓抑制小鼠外周血象的恢复,可能是白花油麻藤促进造血的有效活性部位.

  5. Effects of heterogenous suberect spatholobus stem on peripheral blood cell counts of 60Co γ ray irradiated mice%同名异种鸡血藤对60Co γ射线辐射小鼠外周血象的影响

    Institute of Scientific and Technical Information of China (English)

    王虹; 刘屏; 戴畅; 王东晓

    2007-01-01

    目的:研究密花豆藤(Spatholobus suberectu)、白花油麻藤(Mucuna birdwoodiana)、皱果崖豆藤(Millettia oosperma)、香花崖豆藤(Millettia dielsiana)等4种同名异种鸡血藤对骨髓抑制小鼠外周血象的作用.方法:60Co γ射线亚致死量辐照造成骨髓抑制小鼠模型,灌胃给药,于给药后1、3、7、14和21 d监测其外周血白细胞、红细胞和血小板计数.结果:给予同名异种鸡血藤治疗后,小鼠外周血白细胞、红细胞和血小板计数下降趋势减缓,与对照组比较,白花油麻藤和密花豆藤高、低剂量组的白细胞、红细胞和血小板计数升高,差异有统计学意义(P<0.05).结论:同名异种鸡血藤均可在一定程度上促进辐射小鼠外周血象的恢复,其中密花豆藤和白花油麻藤作用相对较好.

  6. High-energy gamma-ray afterglows from low-luminosity gamma-ray bursts

    OpenAIRE

    He, Hao-Ning; WANG, XIANG-YU; Yu, Yun-Wei; Meszaros, Peter

    2009-01-01

    The observations of gamma-ray bursts (GRBs) such as 980425, 031203 and 060218, with luminosities much lower than those of other classic bursts, lead to the definition of a new class of GRBs -- low-luminosity GRBs. The nature of the outflow responsible for them is not clear yet. Two scenarios have been suggested: one is the conventional relativistic outflow with initial Lorentz factor of order of $\\Gamma_0\\ga 10$ and the other is a trans-relativistic outflow with $\\Gamma_0\\simeq 1-2$. Here we ...

  7. GAMMA RAYS FROM STAR FORMATION IN CLUSTERS OF GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Storm, Emma M.; Jeltema, Tesla E.; Profumo, Stefano [Department of Physics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)

    2012-08-20

    Star formation in galaxies is observed to be associated with gamma-ray emission, presumably from non-thermal processes connected to the acceleration of cosmic-ray nuclei and electrons. The detection of gamma rays from starburst galaxies by the Fermi Large Area Telescope (LAT) has allowed the determination of a functional relationship between star formation rate and gamma-ray luminosity. Since star formation is known to scale with total infrared (8-1000 {mu}m) and radio (1.4 GHz) luminosity, the observed infrared and radio emission from a star-forming galaxy can be used to quantitatively infer the galaxy's gamma-ray luminosity. Similarly, star-forming galaxies within galaxy clusters allow us to derive lower limits on the gamma-ray emission from clusters, which have not yet been conclusively detected in gamma rays. In this study, we apply the functional relationships between gamma-ray luminosity and radio and IR luminosities of galaxies derived by the Fermi Collaboration to a sample of the best candidate galaxy clusters for detection in gamma rays in order to place lower limits on the gamma-ray emission associated with star formation in galaxy clusters. We find that several clusters have predicted gamma-ray emission from star formation that are within an order of magnitude of the upper limits derived in Ackermann et al. based on non-detection by Fermi-LAT. Given the current gamma-ray limits, star formation likely plays a significant role in the gamma-ray emission in some clusters, especially those with cool cores. We predict that both Fermi-LAT over the course of its lifetime and the future Cerenkov Telescope Array will be able to detect gamma-ray emission from star-forming galaxies in clusters.

  8. Radioisotope identification method for poorly resolved gamma-ray spectrum of nuclear security concern

    Energy Technology Data Exchange (ETDEWEB)

    Ninh, Giang Nguyen; Phongphaeth, Pengvanich, E-mail: phongphaeth.p@chula.ac.th; Nares, Chankow [Nuclear Engineering Department, Faculty of Engineering, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330 (Thailand); Hao, Quang Nguyen [Vietnam Atomic Energy Institute, Ministry of Science and Technology, Hanoi (Viet Nam)

    2016-01-22

    Gamma-ray signal can be used as a fingerprint for radioisotope identification. In the context of radioactive and nuclear materials security at the border control point, the detection task can present a significant challenge due to various constraints such as the limited measurement time, the shielding conditions, and the noise interference. This study proposes a novel method to identify the signal of one or several radioisotopes from a poorly resolved gamma-ray spectrum. In this method, the noise component in the raw spectrum is reduced by the wavelet decomposition approach, and the removal of the continuum background is performed using the baseline determination algorithm. Finally, the identification of radioisotope is completed using the matrix linear regression method. The proposed method has been verified by experiments using the poorly resolved gamma-ray signals from various scenarios including single source, mixing of natural uranium with five of the most common industrial radioactive sources (57Co, 60Co, 133Ba, 137Cs, and 241Am). The preliminary results show that the proposed algorithm is comparable with the commercial method.

  9. An attempt to estimate gamma-ray dose rate from radioactive waste storage cask

    Energy Technology Data Exchange (ETDEWEB)

    Pesic, M.; Plecas, I.; Pavlovic, R.; Pavlovic, S. [Institute for Nuclear Sciences ' ' Vinca' ' , Belgrade (Yugoslavia); Sokcic-Kostic, M. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Hauptabteilung Zyklotron

    2001-07-01

    Radioactive waste - {sup 137}Cs and {sup 60}Co contaminated sludge from the irradiated fuel storage pool of the RA research reactor in the Vinca Institute of Nuclear Sciences, Belgrade, is conditioned and stored in specially designed casks in 1997. Main purpose of this paper is to describe an attempt to estimate a gamma-ray ambient dose equivalent rate from the cask with the conditioned sludge by reference Monte Carlo MCNP code and compare the result to the measuring data. The aim of the study is to master with a reliable computational tool that allows faithful estimation of the total ambient gamma-ray dose equivalent rates from the cask. Values of so obtained gamma-ray ambient dose equivalent rates are compared to the measured values at the same spots of the cask and acceptable agreement were found. These data could be used in a further study on minimisation of the total ambient dose equivalent rate of a regular array or random pile of casks, stored in the storage location. (orig.)

  10. Radioisotope identification method for poorly resolved gamma-ray spectrum of nuclear security concern

    Science.gov (United States)

    Ninh, Giang Nguyen; Phongphaeth, Pengvanich; Nares, Chankow; Hao, Quang Nguyen

    2016-01-01

    Gamma-ray signal can be used as a fingerprint for radioisotope identification. In the context of radioactive and nuclear materials security at the border control point, the detection task can present a significant challenge due to various constraints such as the limited measurement time, the shielding conditions, and the noise interference. This study proposes a novel method to identify the signal of one or several radioisotopes from a poorly resolved gamma-ray spectrum. In this method, the noise component in the raw spectrum is reduced by the wavelet decomposition approach, and the removal of the continuum background is performed using the baseline determination algorithm. Finally, the identification of radioisotope is completed using the matrix linear regression method. The proposed method has been verified by experiments using the poorly resolved gamma-ray signals from various scenarios including single source, mixing of natural uranium with five of the most common industrial radioactive sources (57Co, 60Co, 133Ba, 137Cs, and 241Am). The preliminary results show that the proposed algorithm is comparable with the commercial method.

  11. Spectra of {gamma} rays feeding superdeformed bands

    Energy Technology Data Exchange (ETDEWEB)

    Lauritsen, T.; Khoo, T.L.; Henry, R.G. [and others

    1995-08-01

    The spectrum of {gamma}rays coincident with SD transitions contains the transitions which populate the SD band. This spectrum can provide information on the feeding mechanism and on the properties (moment of inertia, collectivity) of excited SD states. We used a model we developed to explain the feeding of SD bands, to calculate the spectrum of feeding {gamma}rays. The Monte Carlo simulations take into account the trigger conditions present in our Eurogam experiment. Both experimental and theoretical spectra contain a statistical component and a broad E2 peak (from transitions occurring between excited states in the SD well). There is good resemblance between the measured and calculated spectra although the calculated multiplicity of an E2 bump is low by {approximately}30%. Work is continuing to improve the quality of the fits, which will result in a better understanding of excited SD states. In addition, a model for the last steps, which cool the {gamma} cascade into the SD yrast line, needs to be developed. A strong M1/E2 low-energy component, which we believe is responsible for this cooling, was observed.

  12. Collimatorless imaging of gamma rays with help of gamma-ray tracking

    CERN Document Server

    Marel, J V D

    2001-01-01

    In many gamma-ray detector systems that are built for imaging purposes Compton scattered photons are suppressed as much as possible. However, the information from photons that scattered inside a detector system can be used to reconstruct the tracks of the photons with help of gamma-ray tracking. Estimates of the incident directions of the photons can be made and an image can be created. Examples of potential applications for this technique are the use as a gamma-camera in medical imaging (e.g. SPECT) or as a detector for PET. Due to the omission of collimators, much higher detection efficiencies can be achieved, reducing the doses required for an image. A gamma-ray tracking method, called backtracking, has been developed for nuclear spectroscopy. The method tracks gamma-rays originating from a point source in the center of a spherical detector system consisting of position-sensitive germanium detectors. This method can also be used as a tracking technique for imaging of an unknown source distribution. With he...

  13. Development of a Small-Sized, Flexible, and Insertable Fiber-Optic Radiation Sensor for Gamma-Ray Spectroscopy.

    Science.gov (United States)

    Yoo, Wook Jae; Shin, Sang Hun; Lee, Dong Eun; Jang, Kyoung Won; Cho, Seunghyun; Lee, Bongsoo

    2015-01-01

    We fabricated a small-sized, flexible, and insertable fiber-optic radiation sensor (FORS) that is composed of a sensing probe, a plastic optical fiber (POF), a photomultiplier tube (PMT)-amplifier system, and a multichannel analyzer (MCA) to obtain the energy spectra of radioactive isotopes. As an inorganic scintillator for gamma-ray spectroscopy, a cerium-doped lutetium yttrium orthosilicate (LYSO:Ce) crystal was used and two solid-disc type radioactive isotopes with the same dimensions, cesium-137 (Cs-137) and cobalt-60 (Co-60), were used as gamma-ray emitters. We first determined the length of the LYSO:Ce crystal considering the absorption of charged particle energy and measured the gamma-ray energy spectra using the FORS. The experimental results demonstrated that the proposed FORS can be used to discriminate species of radioactive isotopes by measuring their inherent energy spectra, even when gamma-ray emitters are mixed. The relationship between the measured photon counts of the FORS and the radioactivity of Cs-137 was subsequently obtained. The amount of scintillating light generated from the FORS increased by increasing the radioactivity of Cs-137. Finally, the performance of the fabricated FORS according to the length and diameter of the POF was also evaluated. Based on the results of this study, it is anticipated that a novel FORS can be developed to accurately measure the gamma-ray energy spectrum in inaccessible locations such as narrow areas and holes. PMID:26343667

  14. Development of a Small-Sized, Flexible, and Insertable Fiber-Optic Radiation Sensor for Gamma-Ray Spectroscopy

    Directory of Open Access Journals (Sweden)

    Wook Jae Yoo

    2015-08-01

    Full Text Available We fabricated a small-sized, flexible, and insertable fiber-optic radiation sensor (FORS that is composed of a sensing probe, a plastic optical fiber (POF, a photomultiplier tube (PMT-amplifier system, and a multichannel analyzer (MCA to obtain the energy spectra of radioactive isotopes. As an inorganic scintillator for gamma-ray spectroscopy, a cerium-doped lutetium yttrium orthosilicate (LYSO:Ce crystal was used and two solid-disc type radioactive isotopes with the same dimensions, cesium-137 (Cs-137 and cobalt-60 (Co-60, were used as gamma-ray emitters. We first determined the length of the LYSO:Ce crystal considering the absorption of charged particle energy and measured the gamma-ray energy spectra using the FORS. The experimental results demonstrated that the proposed FORS can be used to discriminate species of radioactive isotopes by measuring their inherent energy spectra, even when gamma-ray emitters are mixed. The relationship between the measured photon counts of the FORS and the radioactivity of Cs-137 was subsequently obtained. The amount of scintillating light generated from the FORS increased by increasing the radioactivity of Cs-137. Finally, the performance of the fabricated FORS according to the length and diameter of the POF was also evaluated. Based on the results of this study, it is anticipated that a novel FORS can be developed to accurately measure the gamma-ray energy spectrum in inaccessible locations such as narrow areas and holes.

  15. Gamma rays as probes of the Universe

    Science.gov (United States)

    Horns, Dieter; Jacholkowska, Agnieszka

    2016-06-01

    The propagation of γ rays over very large distances provides new insights on the intergalactic medium and on fundamental physics. On their path to the Earth, γ rays can annihilate with diffuse infrared or optical photons of the intergalactic medium, producing e+e- pairs. The density of these photons is poorly determined by direct measurements due to significant galactic foregrounds. Studying the absorption of γ rays from extragalactic sources at different distances allows the density of low-energy diffuse photons to be measured. Gamma-ray propagation may also be affected by new phenomena predicted by extensions of the Standard Model of particle physics. Lorentz Invariance is violated in some models of Quantum Gravity, leading to an energy-dependent speed of light in vacuum. From differential time-of-flight measurements of the most distant γ-ray bursts and of flaring active galactic nuclei, lower bounds have been set on the energy scale of Quantum Gravity. Another effect that may alter γ-ray propagation is predicted by some models of String Theory, namely the mixing of the γ ray with a light fundamental boson called an "axion-like particle", which does not interact with low-energy photons. Such a mixing would make the Universe more transparent to γ rays than what would otherwise be, in a sense it decreases the amount of modification to the spectrum that comes from the extragalactic background light. The present status of the search for all these phenomena in γ-ray astronomy is reviewed. xml:lang="fr"

  16. Measurements of (60)Co in massive steel samples exposed to the Hiroshima atomic bomb explosion.

    Science.gov (United States)

    Gasparro, Joël; Hult, Mikael; Marissens, Gerd; Hoshi, Masaharu; Tanaka, Kenichi; Endo, Satoru; Laubenstein, Matthias; Dombrowski, Harald; Arnold, Dirk

    2012-04-01

    To study discrepancies in retrospective Hiroshima dosimetry, the specific activity of (60)Co in 16 steel samples from Hiroshima was measured using gamma-ray spectrometry in underground laboratories. There is general agreement between these new activity measurements and the specific activities derived from previously calculated dose values on the one hand and former measurements of samples gathered at distances less than 1,000 m from the center of the explosion ( 1,300 m slant range) were mainly cosmogenically induced. Furthermore, at long range, these results are in disagreement with older measurements whose specific activity values were 10 to 100 times higher than predicted by computer model calculations in DS86 and DS02. As a consequence, the previously reported discrepancy is not confirmed. PMID:22378201

  17. 129I, 60Co, and 106Ru measurements on water samples from the Hanford project environs

    International Nuclear Information System (INIS)

    Groundwater flow and contamination patterns beneath the Hanford project reservation have been studied since the early days of the project. The measurement of radioactive materials at concentrations much below those required for radiation protection are useful for tracing groundwater movement and detection of potential contamination problems before they are apt to occur. Groundwater samples from a number of wells on or near the Hanford reservation have been analyzed for 129I by neutron activation analysis and for gamma radioactivity by low-level coincidence gamma-ray spectrometry. The major radionuclides in addition to natural radioactivity detected in the underground waters by gamma-ray spectrometry were 106Ru and 60Co. Local river and rain water samples were also analyzed for 129I and long-lived radionuclides. Special sample collection methods were developed to prevent contamination of the water samples during collection. Anions travel farther than cations in underground water systems since soils are primarily cation exchangers and retain the cations. Anion exchange techniques were used in the field and the laboratory to recover the desired radionuclides. Sample sizes ranged up to several thousand liters. This paper discusses the sample collection methods,analysis methods, and results obtained. The methods used were found to provide high sensitivity for groundwater studies. (auth)

  18. Gamma rays and supernova explosions. [high temperature radiation measurement

    Science.gov (United States)

    Arnett, W. D.

    1977-01-01

    Thermal radiation associated with the explosion of supernovae is investigated. High temperature is required to produce copious gamma radiation of this sort. It appears that type 11 supernovae do not release much of their energy as gamma ray continuum radiation.

  19. The interplanetary gamma ray burst network

    Science.gov (United States)

    Cline, T.

    The Interplanetary Gamma-Ray Burst Network (IPN) is providing gamma-ray burst (GRB) alerts and localizations at the maximum rate anticipated before the launch of the Swift mission. The arc-minute source precision of the IPN is again permitting searches for GRB afterglows in the radio and optical regimes with delays of only hours up to 2 days. The successful addition of the Mars Odyssey mission has compensated for the loss of the asteroid mission NEAR, to reconstitute a fully long- baseline interplanetary network, with Ulysses at > 5 AU and Konus-Wind and HETE-2 near the Earth. In addition to making unassisted GRB localizations that enable a renewed supply of counterpart observations, the Mars/Ulysses/Wind IPN is confirming and reinforcing GRB source localizations with HETE-2. It has also confirmed and reinforced localizations with the BeppoSAX mission before the BeppoSAX termination in May and has detected and localized both SGRs and an unusual hard x-ray transient that is neither an SGR nor a GRB. This IPN is expected to operate until at least 2004.

  20. $\\gamma$-Ray Bursts the Four Crises

    CERN Document Server

    Tavani, M

    1998-01-01

    We discuss some open problems concerning the origin and the emission mechanism of gamma-ray bursts (GRBs) in light of recent developments. If GRBs originate at extragalactic distances, we are facing four crises: (1) an energy crisis, models have to account for more than 10^{53} ergs of energy emitted in the gamma-ray energy band; (2) a spectral crisis, emission models have to account for the surprising `smoothness' of GRB broad-band spectra, with no indication of the predicted spectral `distorsions' caused by inverse Compton scattering in large radiation energy density media, and no evidence for beaming; (3) an afterglow crisis, relativistic shock models have to explain the complexity of the afterglow behavior, the longevity of optical transients detectable up to six months after the burst, the erratic behavior of the radio emission, and the lack of evidence for substantial beaming as indicated by recent searches for GRB afterglows in the X-ray band; (4) a population crisis, from data clearly indicating that ...

  1. Very high energy gamma ray astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Lamb, R.C.; Lewis, D.A.

    1992-02-01

    The second reflector (project GRANITE) is on schedule. At present (January 1992) it and the 10 m reflector are obtaining stereoscopic views of gamma-ray air showers from the Crab Nebula which verify the expected performance of the twin reflector telescopes. With the additional improvements of the upgrade (a pending DOE proposal) the twin reflectors should reach a limiting intensity of 1% that of the Crab. The astonishing early results from the EGRET detector aboard the Compton Gamma Ray Observatory indicate that distant quasars (powered by supermassive black holes) are active at GeV energies. The Whipple instruments are poised to see if such behavior continues above 100 GeV, as well as perform sensitive observations of previously reported GeV (Geminga) and TeV (Hercules X-1, etc.) sources. In addition to observing sources and identifying their location in the sky to one arcminute, experiments are planned to search for WIMPS in the mass range 0.1 to 1 TeV, and to determine the abundance of anti-protons in the cosmic rays. The successful performance of the stereoscopic reflectors demonstrates the feasibility of the concept of arrays of Cherenkov receivers. Design studies for a much larger array (CASITA) are just beginning.

  2. The GAMMA-400 gamma-ray telescope characteristics. Angular resolution and electrons/protons separation

    CERN Document Server

    Leonov, A A; Bonvicini, V; Topchiev, N P; Adriani, O; Aptekar, R L; Arkhangelskaja, I V; Arkhangelskiy, A I; Bergstrom, L; Berti, E; Bigongiari, G; Bobkov, S G; Boezio, M; Bogomolov, E A; Bonechi, S; Bongi, M; Bottai, S; Boyarchuk, K A; Castellini, G; Cattaneo, P W; Cumani, P; Dedenko, G L; De Donato, C; Dogiel, V A; 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; Loginov, V A; Longo, F; Maestro, P; Marrocchesi, P S; Mikhailov, V V; Mocchiutti, E; Moiseev, A A; Mori, N; Moskalenko, I V; Naumov, P Yu; Papini, P; Pearce, M; Picozza, P; Popov, A V; Rappoldi, A; Ricciarini, S; Runtso, M F; Ryde, F; Serdin, O V; Sparvoli, R; Spillantini, P; Suchkov, S I; Tavani, M; Taraskin, A A; Tiberio, A; Tyurin, E M; Ulanov, M V; Vacchi, A; Vannuccini, E; Vasilyev, G I; Yurkin, Yu T; Zampa, N; Zirakashvili, V N; Zverev, V G

    2014-01-01

    The measurements of gamma-ray fluxes and cosmic-ray electrons and positrons in the energy range from 100 MeV to several TeV, which will be implemented by the specially designed GAMMA-400 gamma-ray telescope, concern with the following broad range of science topics. Searching for signatures of dark matter, surveying the celestial sphere in order to study gamma-ray point and extended sources, measuring the energy spectra of Galactic and extragalactic diffuse gamma-ray emission, studying gamma-ray bursts and gamma-ray emission from the Sun, as well as high precision measuring spectra of high-energy electrons and positrons, protons and nuclei up to the knee. To clarify these scientific problems with the new experimental data the GAMMA-400 gamma-ray telescope possesses unique physical characteristics comparing with previous and present experiments. For gamma-ray energies more than 100 GeV GAMMA-400 provides the energy resolution of ~1% and angular resolution better than 0.02 deg. The methods developed to reconstru...

  3. Polarized gamma-rays with laser-Compton backscattering

    Energy Technology Data Exchange (ETDEWEB)

    Ohgaki, H.; Noguchi, T.; Sugiyama, S. [Electrotechnical Lab., Ibaraki (Japan)] [and others

    1995-12-31

    Polarized gamma-rays were generated through laser-Compton backscattering (LCS) of a conventional Nd:YAG laser with electrons circulating in the electron storage ring TERAS at Electrotechnical Laboratory. We measured the energy, the energy spread, and the yield of the gamma-rays to characterize our gamma-ray source. The gamma-ray energy can be varied by changing the energy of the electrons circulating the storage ring. In our case, the energy of electrons in the storage ring were varied its energy from 200 to 750 MeV. Consequently, we observed gamma-ray energies of 1 to 10 MeV with 1064 run laser photons. Furthermore, the gamma-ray energy was extended to 20 MeV by using the 2nd harmonic of the Nd:YAG laser. This shows a good agreement with theoretical calculation. The gamma-ray energy spread was also measured to be 1% FWHM for -1 MeV gamma-rays and to be 4% FWHM for 10 MeV gamma-rays with a narrow collimator that defined the scattering cone. The gamma-ray yield was 47.2 photons/mA/W/s. This value is consistent with a rough estimation of 59.5 photons/mA/W/s derived from theory. Furthermore, we tried to use these gamma-rays for a nuclear fluorescence experiment. If we use a polarized laser beam, we can easily obtain polarized gamma-rays. Elastically scattered photons from {sup 208} Pb were clearly measured with the linearly polarized gamma-rays, and we could assign the parity of J=1 states in the nucleus. We should emphasize that the polarized gamma-ray from LCS is quit useful in this field, because we can use highly, almost completely, polarized gamma-rays. We also use the LCS gamma-rays to measure the photon absorption coefficients. In near future, we will try to generate a circular polarized gamma-ray. We also have a plan to use an FEL, because it can produce intense laser photons in the same geometric configuration as the LCS facility.

  4. The short gamma-ray burst revolution

    International Nuclear Information System (INIS)

    Swift, a dedicated gamma-ray burst (GRB) satellite with ultrarapid slewing capability, and a suite of ground-based (ESO) telescopes have recently achieved a major breakthrough: detecting the first afterglows of short-duration GRBs. The faintness of these afterglows and the diversity of old and young host galaxies lend support to the emerging 'standard model', in which they are created during the merging of two compact objects. However, the afterglow light-curve properties and possible high-redshift origin of some short bursts suggests that more than one progenitor type may be involved. (orig.)

  5. Gamma ray constraints on decaying dark matter

    DEFF Research Database (Denmark)

    Cirelli, M.; Moulin, E.; Panci, P.;

    2012-01-01

    We derive new bounds on decaying dark matter from the gamma ray measurements of (i) the isotropic residual (extragalactic) background by Fermi and (ii) the Fornax galaxy cluster by H.E.S.S. We find that those from (i) are among the most stringent constraints currently available, for a large range...... of dark matter masses and a variety of decay modes, excluding half-lives up to similar to 10(26) to few 10(27) seconds. In particular, they rule out the interpretation in terms of decaying dark matter of the e(+/-) spectral features in PAMELA, Fermi and H.E.S.S., unless very conservative choices...

  6. Two classes of gamma-ray bursts

    CERN Document Server

    Katz, J I

    1995-01-01

    Data from the 3B Catalogue suggest that short and long GRB are the results of different classes of events, rather than different parameter values within a single class: Short bursts have harder spectra in the BATSE bands, but chiefly long bursts are detected at photon energies over 1 MeV, implying that their hard photons are radiated by a process not found in short bursts. The values of \\langle V/V_{max} \\rangle for short and long bursts differ by 4.3 \\sigma, implying different spatial distributions. Only the soft gamma-ray radiation mechanisms are the same in both classes.

  7. Optical telescope BIRT in ORIGIN for gamma ray burst observing

    DEFF Research Database (Denmark)

    Content, Robert; Sharples, Ray; Page, Mathew J.;

    2012-01-01

    The ORIGIN concept is a space mission with a gamma ray, an X-ray and an optical telescope to observe the gamma ray bursts at large Z to determine the composition and density of the intergalactic matter in the line of sight. It was an answer to the ESA M3 call for proposal. The optical telescope...

  8. A separation of electrons and protons in the GAMMA-400 gamma-ray telescope

    CERN Document Server

    Leonov, A A; Bonvicini, V; Topchiev, N P; Adriani, O; Aptekar, R L; Arkhangelskaja, I V; Arkhangelskiy, A I; Bergstrom, L; Berti, E; Bigongiari, G; Bobkov, S G; Boezio, M; Bogomolov, E A; Bonechi, S; Bongi, M; Bottai, S; Castellini, G; Cattaneo, P W; Cumani, P; Dedenko, G L; De Donato, C; Dogiel, V A; 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; Loginov, V A; Longo, F; Maestro, P; Marrocchesi, P S; Mikhailov, V V; Mocchiutti, E; Moiseev, A A; Mori, N; Moskalenko, I V; Naumov, P Yu; Papini, P; Pearce, M; Picozza, P; Popov, A V; Rappoldi, A; Ricciarini, S; Runtso, M F; Ryde, F; Serdin, O V; Sparvoli, R; Spillantini, P; Suchkov, S I; Tavani, M; Taraskin, A A; Tiberio, A; Tyurin, E M; Ulanov, M V; Vacchi, A; Vannuccini, E; Vasilyev, G I; Yurkin, Yu T; Zampa, N; Zirakashvili, V N; Zverev, V G

    2015-01-01

    The GAMMA-400 gamma-ray telescope is intended to measure the fluxes of gamma rays and cosmic-ray electrons and positrons in the energy range from 100 MeV to several TeV. Such measurements concern with the following scientific goals: search for signatures of dark matter, investigation of gamma-ray point and extended sources, studies of the energy spectra of Galactic and extragalactic diffuse emission, studies of gamma-ray bursts and gamma-ray emission from the active Sun, as well as high-precision measurements of spectra of high-energy electrons and positrons, protons, and nuclei up to the knee. The main components of cosmic rays are protons and helium nuclei, whereas the part of lepton component in the total flux is ~10E-3 for high energies. In present paper, the capability of the GAMMA-400 gamma-ray telescope to distinguish electrons and positrons from protons in cosmic rays is investigated. The individual contribution to the proton rejection is studied for each detector system of the GAMMA-400 gamma-ray tel...

  9. High Energy Gamma-Ray Emission from Gamma-Ray Bursts - Before GLAST

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Yi-Zhong; Piran, Tsvi

    2011-11-29

    Gamma-ray bursts (GRBs) are short and intense emission of soft {gamma}-rays, which have fascinated astronomers and astrophysicists since their unexpected discovery in 1960s. The X-ray/optical/radio afterglow observations confirm the cosmological origin of GRBs, support the fireball model, and imply a long-activity of the central engine. The high-energy {gamma}-ray emission (> 20 MeV) from GRBs is particularly important because they shed some lights on the radiation mechanisms and can help us to constrain the physical processes giving rise to the early afterglows. In this work, we review observational and theoretical studies of the high-energy emission from GRBs. Special attention is given to the expected high-energy emission signatures accompanying the canonical early-time X-ray afterglow that was observed by the Swift X-ray Telescope. We also discuss the detection prospect of the upcoming GLAST satellite and the current ground-based Cerenkov detectors.

  10. Improved Gamma-Ray Flux Monitoring at the High Intensity Gamma-Ray Source (HIGS)

    Science.gov (United States)

    Reynolds, Robert

    2002-10-01

    An improved gamma-ray beam flux monitor has been built for use at the High Intensity Gamma-Ray Source at the Duke University Free Electron Laser Laboratories. It is important to know precisely the gamma-ray flux of this beam. It is also important to limit beam attenuation to a minimum while making an accurate flux measurement. The improvements from a more accurate gamma-ray intensity monitor will allow for more precise cross-section measurements and will be valuable to many of the experiments conducted at HIGS. The detector consists of a thin scintillator optically coupled to two photomultiplier tubes, a thin foil, and then another thin scintillator attached to two photomultiplier tubes. The front scintillator is used to veto counts from charged particles emitted upstream in the beam-line. The preliminary tests of the monitor show very promising results and after slight adjustments and calibrations, the detector will be ready to acquire accurate beam intensity measurements while contributing very little to beam attenuation.

  11. Balloon-borne gamma-ray polarimetry

    CERN Document Server

    Pearce, Mark

    2011-01-01

    The physical processes postulated to explain the high-energy emission mechanisms of compact astrophysical sources often yield polarised soft gamma rays (X-rays). PoGOLite is a balloon-borne polarimeter operating in the 25-80 keV energy band. The polarisation of incident photons is reconstructed using Compton scattering and photoelectric absorption in an array of phoswich detector cells comprising plastic and BGO scintillators, surrounded by a BGO side anticoincidence shield. The polarimeter is aligned to observation targets using a custom attitude control system. The maiden balloon flight is scheduled for summer 2011 from the Esrange Space Centre with the Crab and Cygnus X-1 as the primary observational targets.

  12. The Gamma-Ray Burst - Supernova Connection

    CERN Document Server

    Hjorth, Jens

    2011-01-01

    A preponderance of evidence links long-duration, soft-spectrum gamma-ray bursts (GRBs) with the death of massive stars. The observations of the GRB-supernova (SN) connection present the most direct evidence of this physical link. We summarize 30 GRB-SN associations and focus on five ironclad cases, highlighting the subsequent insight into the progenitors enabled by detailed observations. We also address the SN association (or lack thereof) with several sub-classes of GRBs, finding that the X-ray Flash (XRF) population is likely associated with massive stellar death whereas short-duration events likely arise from an older population not readily capable of producing a SN concurrent with a GRB. Interestingly, a minority population of seemingly long-duration, soft-spectrum GRBs show no evidence for SN-like activity; this may be a natural consequence of the range of Ni-56 production expected in stellar deaths.

  13. Gamma Rays from Top-Mediated Dark Matter Annihilations

    OpenAIRE

    Jackson, C.B.(Department of Physics, University of Texas at Arlington, Arlington, TX 76019, USA); Servant, Géraldine; Shaughnessy, Gabe; Tim M.P. Tait; Taoso, Marco

    2013-01-01

    Lines in the energy spectrum of gamma rays are a fascinating experimental signal, which are often considered "smoking gun" evidence of dark matter annihilation. The current generation of gamma ray observatories are currently closing in on parameter space of great interest in the context of dark matter which is a thermal relic. We consider theories in which the dark matter's primary connection to the Standard Model is via the top quark, realizing strong gamma ray lines consistent with a therma...

  14. Assessment of gamma ray-induced DNA damage in Lasioderma serricorne using the comet assay

    Science.gov (United States)

    Kameya, Hiromi; Miyanoshita, Akihiro; Imamura, Taro; Todoriki, Setsuko

    2012-03-01

    We attempted a DNA comet assay under alkaline conditions to verify the irradiation treatment of pests. Lasioderma serricorne (Fabricius) were chosen as test insects and irradiated with gamma rays from a 60Co source at 1 kGy. We conducted the comet assay immediately after irradiation and over time for 7 day. Severe DNA fragmentation in L. serricorne cells was observed just after irradiation and the damage was repaired during the post-irradiation period in a time-dependent manner. The parameters of the comet image analysis were calculated, and the degree of DNA damage and repair were evaluated. Values for the Ratio (a percentage determined by fluorescence in the damaged area to overall luminance, including intact DNA and the damaged area of a comet image) of individual cells showed that no cells in the irradiated group were included in the Ratiocomet assay under alkaline conditions, combined with comet image analysis, can be used to identify irradiation history.

  15. Development of an optimized Compton suppression gamma-ray spectrometric system using Monte Carlo simulation.

    Science.gov (United States)

    Choi, Y; Lee, K B; Kim, K J; Han, J; Yi, E S

    2016-03-01

    We have chosen to establish the Compton Suppression Spectrometer (CSS) for low activity environmental samples with a high purity germanium (HPGe) primary detector and a removable plug-in detector (NaI(Tl)) surrounded with a cylindrical annulus guard detector (NaI(Tl)). Monte Carlo simulation with PENELOPE (PENetration and Energy LOss of Positrons and Electrons) is used to determine the optimal geometry of the CSS. To verify a correlation between experiment and simulation, the energy distribution of (137)Cs and (60)Co point sources is measured and simulated for each condition. The CSS parameters are studied to determine optimal detector geometry and Compton Suppression Factor (CSF). The timing resolution of the CSS was found to be 44ns (FWHM), which is an outstanding result in the semiconductor-based gamma-ray spectrometry. All measured values of CSF agree within 5% with the values obtained from the simulation. The optimum geometry and CSF values are discussed. PMID:26778448

  16. Assessment of differences between X and gamma rays in order to validate a new generation of irradiators for insect sterilization

    Energy Technology Data Exchange (ETDEWEB)

    Mastrangelo, Thiago; Walder, Julio M.M., E-mail: piaui@cena.usp.b [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil); Parker, Andrew G.; Jessup, Andrew; Orozco-Davila, Dina; Islam, Amirul; Dammalage, Thilakasiri, E-mail: A.Jessup@iaea.or [Joint FAO/IAEA-UN A-2444, Seibersdorf (Austria). Insect Pest Control Subprogramme; Pereira, Rui, E-mail: R.Cardoso-Pereira@iaea.or [Joint FAO/IAEA-UN, Vienna (Austria). Insect Pest Control Subprogramme

    2009-07-01

    Recent fears of terrorism provoked an increase in delays and denials of transboundary shipments of radioisotopes. This represents a serious constraint to sterile insect technique (SIT) programs around the world as they rely on the use of ionizing energy from radioisotopes for insect sterilization. In order to validate a novel Xray irradiator, a series of studies on Ceratitis capitata (Wiedemann) and Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) were carried out, comparing the relative biological effectiveness (RBE) between X-rays and traditional gamma radiation from {sup 60}Co. Male C. capitata pupae and pupae of both sexes of A. fraterculus, both 24 to 48 h before adult emergence, were irradiated with doses ranging from 15 to 120 Gy and 10 to 70 Gy respectively. Estimated mean doses of 91.2 Gy of X and 124.9 Gy of gamma radiation induced 99% sterility in C. capitata males. Irradiated A. fraterculus were 99% sterile at about 40-60 Gy for both radiation treatments. Standard quality control parameters were not significantly affected by the two types of radiation. There were no significant differences between X and gamma radiation regarding mating indices. The RBE did not differ significantly between the tested X and gamma radiation, and X-rays are as biologically effective for SIT purposes as gamma rays are. This work confirms the suitability of this new generation of X-ray irradiators for pest control programs in UN Member States. (author)

  17. A standard Fricke dosimeter compared to an ionization chamber used for dosimetric characterization of 60Co photon beam

    Science.gov (United States)

    Moussous, Ouiza; Medjadj, Toufik

    2016-06-01

    The main objective of this study was to investigate the Fricke dosimeter water equivalent system for measurement of dosimetric parameters for photon beam. The parameters measured with the Fricke dosimeter were compared to those obtained with an ionization chamber. In this work characteristics for 60Co γ-rays of field sizes ranging from 5 × 5 cm2 to 20 × 20 cm2 are reported. The measurements were carried out in the secondary standard dosimetry laboratory using a collimated 60Co gamma source therapy unit. The 60Co beam output in terms of absorbed dose to water was obtained as per IAEA TRS 398 recommendations using cylindrical ionization chamber, whose ND,w has been supplied by the IAEA's reference laboratory. Specific quantities measured include: output factors, peak scatter factor, lateral beam profiles and percentage depth dose. The Fricke dosimeters were irradiated in a water phantom using the suitable poly (methyl methacrylate), PMMA stand. Our results demonstrate that Fricke dosimeter and ionization chamber agree with each other.

  18. The Space-Based Gamma-Ray Telescope GAMMA-400 and Its Scientific Goals

    CERN Document Server

    Galper, A M; Aptekar, R L; Arkhangelskaja, I V; Arkhangelskiy, A I; Avanesov, G A; Bergstrom, L; Bogomolov, E A; Boezio, M; Bonvicini, V; Boyarchuk, K A; Dogiel, V A; Gusakov, Yu V; Fradkin, M I; Fuglesang, Ch; Hnatyk, B I; Kachanov, V A; Kadilin, V V; Kaplin, V A; Kheymits, M D; Korepanov, V; Larsson, J; Leonov, A A; Longo, F; Maestro, P; Marrocchesi, P; Mikhailov, V V; Mocchiutti, E; Moiseev, A A; Mori, N; Moskalenko, I; Naumov, P Yu; Papini, P; Pearce, M; Picozza, P; Runtso, M F; Ryde, F; Sparvoli, R; Spillantini, P; Suchkov, S I; Tavani, M; Topchiev, N P; Vacchi, A; Vannuccini, E; Vasiliev, G I; Yurkin, Yu T; Zampa, N; Zarikashvili, V N; Zverev, V G

    2013-01-01

    The design of the new space-based gamma-ray telescope GAMMA-400 is presented. GAMMA-400 is optimized for the energy 100 GeV with the best parameters: the angular resolution ~0.01 deg, the energy resolution ~1%, and the proton rejection factor ~10E6, but is able to measure gamma-ray and electron + positron fluxes in the energy range from 100 MeV to 10 TeV. GAMMA-400 is aimed to a broad range of science topics, such as search for signatures of dark matter, studies of Galactic and extragalactic gamma-ray sources, Galactic and extragalactic diffuse emission, gamma-ray bursts, as well as high-precision measurements of spectra of cosmic-ray electrons + positrons, and nuclei.

  19. ICF gamma-ray reaction history diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, H W; Young, C S; Mack, J M; Kim, Y H; McEvoy, A; Evans, S; Sedillo, T; Batha, S; Schmitt, M; Wilson, D C; Langenbrunner, J R [Los Alamos National Laboratory, P.O Box 1663, M/S E526, Los Alamos, NM 87545 (United States); Malone, R; Kaufman, M I; Cox, B C; Frogget, B; Tunnell, T W [National Security Technologies, Los Alamos, NM 87544 (United States); Miller, E K [National Security Technologies, Special Technologies Laboratory, Santa Barbara, California, 93111 (United States); Ali, Z A [National Security Technologies, Livermore, CA, 94550 (United States); Stoeffl, W [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Horsfield, C J, E-mail: herrmann@lanl.go [Atomic Weapons Establishment, Aldermaston, Reading, RG7 4PR (United Kingdom)

    2010-08-01

    Reaction history measurements, such as nuclear bang time and burn width, are fundamental components of diagnosing ICF implosions and will be employed to help steer the National Ignition Facility (NIF) towards ignition. Fusion gammas provide a direct measure of nuclear interaction rate (unlike x-rays) without being compromised by Doppler spreading (unlike neutrons). Gas Cherenkov Detectors that convert fusion gamma rays to UV/visible Cherenkov photons for collection by fast optical recording systems have established their usefulness in illuminating ICF physics in several experimental campaigns at OMEGA. In particular, bang time precision better than 25 ps has been demonstrated, well below the 50 ps accuracy requirement defined by the NIF. NIF Gamma Reaction History (GRH) diagnostics are being developed based on optimization of sensitivity, bandwidth, dynamic range, cost, and NIF-specific logistics, requirements and extreme radiation environment. Implementation will occur in two phases. The first phase consists of four channels mounted to the outside of the target chamber at {approx}6 m from target chamber center (GRH-6m) coupled to ultra-fast photo-multiplier tubes (PMT). This system is intended to operate in the 10{sup 13}-10{sup 17} neutron yield range expected during the early THD campaign. It will have high enough bandwidth to provide accurate bang times and burn widths for the expected THD reaction histories (> 80 ps fwhm). Successful operation of the first GRH-6m channel has been demonstrated at OMEGA, allowing a verification of instrument sensitivity, timing and EMI/background suppression. The second phase will consist of several channels located just inside the target bay shield wall at 15 m from target chamber center (GRH-15m) with optical paths leading through the cement shield wall to well-shielded streak cameras and PMTs. This system is intended to operate in the 10{sup 16}-10{sup 20} yield range expected during the DT ignition campaign, providing higher

  20. ICF gamma-ray reaction history diagnostics

    Science.gov (United States)

    Herrmann, H. W.; Young, C. S.; Mack, J. M.; Kim, Y. H.; McEvoy, A.; Evans, S.; Sedillo, T.; Batha, S.; Schmitt, M.; Wilson, D. C.; Langenbrunner, J. R.; Malone, R.; Kaufman, M. I.; Cox, B. C.; Frogget, B.; Miller, E. K.; Ali, Z. A.; Tunnell, T. W.; Stoeffl, W.; Horsfield, C. J.; Rubery, M.

    2010-08-01

    Reaction history measurements, such as nuclear bang time and burn width, are fundamental components of diagnosing ICF implosions and will be employed to help steer the National Ignition Facility (NIF) towards ignition. Fusion gammas provide a direct measure of nuclear interaction rate (unlike x-rays) without being compromised by Doppler spreading (unlike neutrons). Gas Cherenkov Detectors that convert fusion gamma rays to UV/visible Cherenkov photons for collection by fast optical recording systems have established their usefulness in illuminating ICF physics in several experimental campaigns at OMEGA. In particular, bang time precision better than 25 ps has been demonstrated, well below the 50 ps accuracy requirement defined by the NIF. NIF Gamma Reaction History (GRH) diagnostics are being developed based on optimization of sensitivity, bandwidth, dynamic range, cost, and NIF-specific logistics, requirements and extreme radiation environment. Implementation will occur in two phases. The first phase consists of four channels mounted to the outside of the target chamber at ~6 m from target chamber center (GRH-6m) coupled to ultra-fast photo-multiplier tubes (PMT). This system is intended to operate in the 1013-1017 neutron yield range expected during the early THD campaign. It will have high enough bandwidth to provide accurate bang times and burn widths for the expected THD reaction histories (> 80 ps fwhm). Successful operation of the first GRH-6m channel has been demonstrated at OMEGA, allowing a verification of instrument sensitivity, timing and EMI/background suppression. The second phase will consist of several channels located just inside the target bay shield wall at 15 m from target chamber center (GRH-15m) with optical paths leading through the cement shield wall to well-shielded streak cameras and PMTs. This system is intended to operate in the 1016-1020 yield range expected during the DT ignition campaign, providing higher temporal resolution for the

  1. Classifying Unidentified Gamma-ray Sources

    CERN Document Server

    Salvetti, David

    2016-01-01

    During its first 2 years of mission the Fermi-LAT instrument discovered more than 1,800 gamma-ray sources in the 100 MeV to 100 GeV range. Despite the application of advanced techniques to identify and associate the Fermi-LAT sources with counterparts at other wavelengths, about 40% of the LAT sources have no a clear identification remaining "unassociated". The purpose of my Ph.D. work has been to pursue a statistical approach to identify the nature of each Fermi-LAT unassociated source. To this aim, we implemented advanced machine learning techniques, such as logistic regression and artificial neural networks, to classify these sources on the basis of all the available gamma-ray information about location, energy spectrum and time variability. These analyses have been used for selecting targets for AGN and pulsar searches and planning multi-wavelength follow-up observations. In particular, we have focused our attention on the search of possible radio-quiet millisecond pulsar (MSP) candidates in the sample of...

  2. Radio flares from gamma-ray bursts

    CERN Document Server

    Kopac, D; 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 the shell thickness regime that is more realistic than the simple assumption of thick- or thin-shell approximations. Building on earlier work by Mundell et al. (2007) and Melandri et al. (2010) in which the typical frequency of the reverse shock was suggested to lie at radio, rather than optical wavelengths at early times, we show that the brightest and most distinct reverse-shock radio signatures are detectable up to 0.1 -- 1 day after the burst, emphasizing the need for rapid radio follow-up. Detection is easier for bursts with later opt...

  3. Gamma ray tests of Minimal Dark Matter

    Energy Technology Data Exchange (ETDEWEB)

    Cirelli, Marco [Institut de Physique Théorique, Université Paris Saclay, CNRS, CEA, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Hambye, Thomas [Service de Physique Theórique, Université Libre de Bruxelles, Boulevard du Triomphe, CP225, 1050 Brussels (Belgium); Panci, Paolo [Institut d’Astrophysique de Paris, UMR 7095 CNRS, Université Pierre et Marie Curie, 98 bis Boulevard Arago, Paris 75014 (France); Sala, Filippo; Taoso, Marco [Institut de Physique Théorique, Université Paris Saclay, CNRS, CEA, Orme des Merisiers, F-91191 Gif-sur-Yvette (France)

    2015-10-12

    We reconsider the model of Minimal Dark Matter (a fermionic, hypercharge-less quintuplet of the EW interactions) and compute its gamma ray signatures. We compare them with a number of gamma ray probes: the galactic halo diffuse measurements, the galactic center line searches and recent dwarf galaxies observations. We find that the original minimal model, whose mass is fixed at 9.4 TeV by the relic abundance requirement, is constrained by the line searches from the Galactic Center: it is ruled out if the Milky Way possesses a cuspy profile such as NFW but it is still allowed if it has a cored one. Observations of dwarf spheroidal galaxies are also relevant (in particular searches for lines), and ongoing astrophysical progresses on these systems have the potential to eventually rule out the model. We also explore a wider mass range, which applies to the case in which the relic abundance requirement is relaxed. Most of our results can be safely extended to the larger class of multi-TeV WIMP DM annihilating into massive gauge bosons.

  4. Mercuric Iodide Anticoincidence Shield for Gamma-Ray Spectrometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We utilize a new detector material, polycrystalline mercuric iodide, for background suppression by active anticoincidence shielding in gamma-ray spectrometers. Two...

  5. Mercuric Iodide Anticoincidence Shield for Gamma-Ray Spectrometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to utilize a new detector material, polycrystalline mercuric iodide, for background suppression by active anticoincidence shielding in gamma-ray...

  6. X- and gamma-ray signatures of type Ia supernovae

    International Nuclear Information System (INIS)

    Using a Monte Carlo code, the hard X-ray continuum and gamma-ray line emissions of various theoretical models of Type Ia supernova explosions are investigated. The influence of the distributions of velocity, mass, Ni-56, and heavy elements on the spectral and temporal evolution of the radiations (ultimately derived from the positrons and gamma-ray lines of the decay chain) is described. For the first 300-400 days of the explosion, the correspondence between the parameters of an explosion model and its hard photon signatures is derived. The effect of mixing instabilities is also studied, and estimates of the future detectability of the derived hard X- and gamma-ray features are presented. It is found that OSEE on the Gamma-Ray Observatory can detect both gamma-ray lines and the hard X-ray continuum from any Type Ia supernova within 10 Mpc of earth. 52 refs

  7. 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 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

  8. Gamma rays induced bold seeded high yielding mutant in chickpea

    International Nuclear Information System (INIS)

    In pulses especially in chickpea (Cicer arietinum L.), genetic variability has been exhausted due to natural selection and hence conventional breeding methods are not very fruitful. Mutation techniques are the best methods to enlarge the genetically conditioned variability of a species within a short time and have played a significant role in the development of many crop varieties. Investigations on the effects of ionizing radiations and chemical mutagens in induction of macro-mutations have received much attention owing to their utmost importance in plant breeding. The present study reports a bold seeded mutant in chickpea, the most dominating pulse crop on the Indian subcontinent. Fresh seeds of chickpea variety 'Pusa-212' were procured from IARI, New Delhi and treated with different doses/concentrations of gamma rays (60Co source at NBRI, Lucknow) and ethyl methanesulphonate (EMS), individually as well as in combination, to raise the M1 generation. Seeds of M1 plants were sown to raise M2 plant progenies. A bold seeded mutant was isolated from 400 Gy gamma ray treatments. The mutant was confirmed as true bred, all the mutant seeds gave rise to morphologically similar plants in M3, which were quite distinct from the control. The bold seeded mutant showed 'gigas' characteristics and vigorous growth. The plant remained initially straight but later on attained a trailing habit due to heavy secondary branching. The leaves, petioles, flowers, pods and seeds were almost double that of the parent variety, in size. The flowering occurred 10 days later than the parent and maturity was also delayed accordingly. Observations were recorded on various quantitative traits. Plant height and number of primary branches showed a significant improvement over the parent. It is interesting to note that the number of pods and number of seeds per pod significantly decreased. However, the hundred seed weight (31.73±0.59g) in the mutant plants was more than double in the parent variety

  9. Studying the WHIM with Gamma Ray Bursts

    CERN Document Server

    Branchini, E; Corsi, A; Martizzi, D; Amati, L; Herder, J W den; Galeazzi, M; Gendre, B; Kaastra, J; Moscardini, L; Nicastro, F; Ohashi, T; Paerels, F; Piro, L; Roncarelli, M; Takei, Y; Viel, M

    2009-01-01

    We assess the possibility to detect and characterize the physical state of the missing baryons at low redshift by analyzing the X-ray absorption spectra of the Gamma Ray Burst [GRB] afterglows, measured by a micro calorimeters-based detector with 3 eV resolution and 1000 cm2 effective area and capable of fast re-pointing, similar to that on board of the recently proposed X-ray satellites EDGE and XENIA. For this purpose we have analyzed mock absorption spectra extracted from different hydrodynamical simulations used to model the properties of the Warm Hot Intergalactic Medium [WHIM]. These models predict the correct abundance of OVI absorption lines observed in UV and satisfy current X-ray constraints. According to these models space missions like EDGE and XENIA should be able to detect about 60 WHIM absorbers per year through the OVII line. About 45 % of these have at least two more detectable lines in addition to OVII that can be used to determine the density and the temperature of the gas. Systematic error...

  10. An analysis of a spreader bar crane mounted gamma-ray radiation detection system

    Science.gov (United States)

    Grypp, Matthew David

    Over 95% of imports entering the United States from outside North America arrive via cargo containers by sea at 329 ports of entry. The current layered approach for the detection only scans 5% of cargo bound for the United States. This is inadequate to protect our country. This research involved the building of a gamma-ray radiation detection system used for cargo scanning. The system was mounted on a spreader bar crane (SBC) at the Port of Tacoma (PoT) and the applicability and capabilities of the system were analyzed. The detection system provided continuous count rate and spectroscopic data among three detectors while operating in an extreme environment. In a separate set of experiments, 60Co and 137Cs sources were positioned inside a cargo container and data were recorded for several count times. The Monte Carlo N-Particle (MCNP) code was used to simulate a radioactive source inside an empty cargo container and the results were compared to experimentally recorded data. The detection system demonstrated the ability to detect 60Co, 137Cs, 192 Ir, highly-enriched uranium (HEU), and weapons-grade plutonium (WGPu) with minimum detectable activities (MDA) of 5.9 +/- 0.4 microcuries (muCi), 19.3 +/- 1.1 muCi, 11.7 +/- 0.6 muCi, 3.5 +/- 0.3 kilograms (kg), and 30.6 +/- 1.3 grams (g), respectively. This system proved strong gamma-ray detection capabilities, but was limited in the detection of fissile materials Additional details of this system are presented and advantages of this approach to cargo scanning over current approaches are discussed.

  11. Gamma Ray Bursts and the Fermi Gamma Ray Space Telescope: Notes to the La Plata Lectures

    CERN Document Server

    Dermer, Charles D

    2008-01-01

    Gamma-ray bursts (GRBs) are a mixed class of sources consisting of, at least, the long duration and short-hard subclasses, the X-ray flashes, and the low-luminosity GRBs. In all cases, the release of enormous amounts of energy on a short timescale makes an energetic, relativistic or mildly relativistic fireball that expands until it reaches a coasting Lorentz factor determined by the amount of baryons mixed into the fireball. Radiation is produced when the blast wave interacts with the surrounding medium at an external shock, or when shell collisions dissipate kinetic energy at internal shocks. This series of notes is organized as follows: (1) The observational situation of GRBs is summarized; (2) Progenitor models of GRBs are described; (3) An overview of the the blast-wave physics used to model leptonic emissions is given; (4) GRB physics is applied to hadronic acceleration and ultra-high energy cosmic ray production; (5) Prospects for GRB physics and gamma-ray astronomy with the Fermi Gamma-ray Space Teles...

  12. The First Fermi Gamma-ray Burst Monitor (GBM) Terrestrial Gamma-ray Flash (TGF) Catalog

    Science.gov (United States)

    Briggs, Michael; Connaughton, Valerie; Stanbro, Matthew; Zhang, Binbin; Bhat, Narayana; Fishman, Gerald; Roberts, Oliver; Fitzpatrick, Gerard; McBreen, Shelia; Grove, Eric; Chekhtman, Alexandre

    2015-04-01

    We present summary results from the first catalog of Terrestrial Gamma-ray Flashes (TGFs) detected with the Gamma-ray Burst Monitor (GBM) on the Fermi Space Telescope. The catalog reports parameters for over 2700 TGFs. Since the launch of Fermi in 2008 the TGF detection sensitivity of GBM has been improved several times, both in the flight software and in ground analysis. Starting in 2010 July individual photons were downloaded for portions of the orbits, enabling an off-line search that found weaker and shorter TGFs. Since 2012 November 26 this telemetry mode has been extended to continuous coverage. The TGF sample is reliable, with cosmic rays rejected using data both from Fermi GBM and from the Large Area Telescope on Fermi. The online catalog include times (UTC and solar), spacecraft geographic positions, durations, count intensities and Bayesian Block durations. The catalog includes separate tables for bright TGFs detected by the flight software and for Terrestrial Electron Beams (TEBs).

  13. The Most Remote Gamma-Ray Burst

    Science.gov (United States)

    2000-10-01

    ESO Telescopes Observe "Lightning" in the Young Universe Summary Observations with telescopes at the ESO La Silla and Paranal observatories (Chile) have enabled an international team of astronomers [1] to measure the distance of a "gamma-ray burst", an extremely violent, cosmic explosion of still unknown physical origin. It turns out to be the most remote gamma-ray burst ever observed . The exceedingly powerful flash of light from this event was emitted when the Universe was very young, less than about 1,500 million years old, or only 10% of its present age. Travelling with the speed of light (300,000 km/sec) during 11,000 million years or more, the signal finally reached the Earth on January 31, 2000. The brightness of the exploding object was enormous, at least 1,000,000,000,000 times that of our Sun, or thousands of times that of the explosion of a single, heavy star (a "supernova"). The ESO Very Large Telescope (VLT) was also involved in trail-blazing observations of another gamma-ray burst in May 1999, cf. ESO PR 08/99. PR Photo 28a/00 : Sky field near GRB 000131 . PR Photo 28b/00 : The fading optical counterpart of GRB 000131 . PR Photo 28c/00 : VLT spectrum of GRB 000131 . What are Gamma-Ray Bursts? One of the currently most active fields of astrophysics is the study of the mysterious events known as "gamma-ray bursts" . They were first detected in the late 1960's by instruments on orbiting satellites. These short flashes of energetic gamma-rays last from less than a second to several minutes. Despite much effort, it is only within the last few years that it has become possible to locate the sites of some of these events (e.g. with the Beppo-Sax satellite ). Since the beginning of 1997, astronomers have identified about twenty optical sources in the sky that are associated with gamma-ray bursts. They have been found to be situated at extremely large (i.e., "cosmological") distances. This implies that the energy release during a gamma-ray burst within a few

  14. Characterization of barite and crystal glass as attenuators in X-ray and gamma radiation shieldings

    International Nuclear Information System (INIS)

    Aiming to determine the barium sulphate (BaSO4) ore and crystal glass attenuation features, both utilized as shieldings against ionizing X and gamma radiations in radiographic installations, a study of attenuation using barite plaster and barite concrete was carried out, which are used, respectively, on wall coverings and in block buildings. The crystal glass is utilized in screens and in windows. To do so, ten plates of barite plaster and three of barite concrete with 900 cm2 and with an average thickness ranging from 1 to 5 cm, and three plates of crystal glass with 323 cm2 and with thicknesses of 1, 2 and 4 cm were analyzed. The samples were irradiated with X-rays with potentials of 60, 80, 110 and 150 kilovolts, and also with 60Co gamma rays. Curves of attenuation were obtained for barite plaster and barite concrete (mGy/mA.min) and (mGy/h), both at 1 meter, as a function of thickness and curve of transmission through barite plaster and barite concrete as a function of the thickness. The equivalent thicknesses of half and tenth value layers for barite plaster, barite concrete and crystal glass for all X-Ray energies were also determined. (author)

  15. Ana Delia, mutant of Jamaica flower (Hibiscus sabdariffa sp.) obtained in Cuba through mutation induction with gamma-rays of 60Co

    International Nuclear Information System (INIS)

    At the National Institute of Agricultural Sciences was obtained a mutant of Hibiscus sabdariffa variety that differs from the donor (Yersy) in the cycle, color of leaves,stems, flowers and fruits in the form of leaves and yield per plant

  16. VHE gamma-ray observations of Markarian 501

    OpenAIRE

    Whipple Collaboration; Breslin, A. C.; Bond, I. H.; Bradbury, S. M.; J. H. Buckley(Department of Physics, Washington University, St. Louis, USA); Burdett, A. M.; Carson, M. J.; Carter-Lewis, D. A.; Catanese, M.; Cawley, M. F.; Dunlea, S.; D'Vali, M.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.

    1999-01-01

    Markarian 501, a nearby (z=0.033) X-ray selected BL Lacertae object, is a well established source of Very High Energy (VHE, E>=300 GeV) gamma rays. Dramatic variability in its gamma-ray emission on time-scales from years to as short as two hours has been detected. Multiwavelength observations have also revealed evidence that the VHE gamma-ray and hard X-ray fluxes may be correlated. Here we present results of observations made with the Whipple Collaboration's 10 m Atmospheric Cerenkov Imaging...

  17. MIRAX sensitivity for Gamma Ray Bursts

    Science.gov (United States)

    Sacahui, J. R.; Penacchioni, A. V.; Braga, J.; Castro, M. A.; D'Amico, F.

    2016-03-01

    In this work we present the detection capability of the MIRAX (Monitor e Imageador de RAios-X) experiment for Gamma-Ray Bursts (GRBs). MIRAX is an X-ray astronomy mission designed to perform a wide band hard X-ray (10-200 keV) survey of the sky, especially in the Galactic plane. With a total detection area of 169 cm2, large field of view (FoV, 20 ° × 20 °), angular resolution of 1°45‧ and good spectral and time resolution (∼8% at 60 keV, 10 μs), MIRAX will be optimized for the detection and study of transient sources, such as accreting neutron stars (NS), black holes (BH), Active Galactic Nuclei (AGNs), and both short and long GRBs. This is especially important because MIRAX is expected to operate in an epoch when probably no other hard X-ray wide-field imager will be active. We have performed detailed simulations of MIRAX GRB observations using the GEANT4 package, including the background spectrum and images of GRB sources in order to provide accurate predictions of the sensitivity for the expected GRB rate to be observed. MIRAX will be capable of detecting ∼44 GRBs per year up to redshifts of ∼4.5. The MIRAX mission will be able to contribute significantly to GRB science by detecting a large number of GRBs per year with wide band spectral response. The observations will contribute mainly to the part of GRB spectra where a thermal emission is predicted by the Fireball model. We also discuss the possibility of detecting GRB afterglows in the X-ray band with MIRAX.

  18. Significance of medium energy gamma ray astronomy in the study of cosmic rays

    Science.gov (United States)

    Fichtel, C. E.; Kniffen, D. A.; Thompson, D. J.; Bignami, G. F.; Cheung, C. Y.

    1975-01-01

    Medium energy (about 10 to 30 MeV) gamma ray astronomy provides information on the product of the galactic electron cosmic ray intensity and the galactic matter to which the electrons are dynamically coupled by the magnetic field. Because high energy (greater than 100 MeV) gamma ray astronomy provides analogous information for the nucleonic cosmic rays and the relevant matter, a comparison between high energy and medium energy gamma ray intensities provides a direct ratio of the cosmic ray electrons and nucleons throughout the galaxy. A calculation of gamma ray production by electron bremsstrahlung shows that: bremsstrahlung energy loss is probably not negligible over the lifetime of the electrons in the galaxy; and the approximate bremsstrahlung calculation often used previously overestimates the gamma ray intensity by about a factor of two. As a specific example, expected medium energy gamma ray intensities are calculated for the speral arm model.

  19. Central Engine Memory of Gamma-Ray Bursts and Soft Gamma-Ray Repeaters

    CERN Document Server

    Zhang, Bin-Bin; Castro-Tirado, Alberto J

    2016-01-01

    Gamma-ray Bursts (GRBs) are bursts of $\\gamma$-rays generated from relativistic jets launched from catastrophic events such as massive star core collapse or binary compact star coalescence. Previous studies suggested that GRB emission is erratic, with no noticeable memory in the central engine. Here we report a discovery that similar light curve patterns exist within individual bursts for at least some GRBs. Applying the Dynamic Time Warping (DTW) method, we show that similarity of light curve patterns between pulses of a single burst or between the light curves of a GRB and its X-ray flare can be identified. This suggests that the central engine of at least some GRBs carries "memory" of its activities. We also show that the same technique can identify memory-like emission episodes in the flaring emission in Soft Gamma-Ray Repeaters (SGRs), which are believed to be Galactic, highly magnetized neutron stars named magnetars. Such a phenomenon challenges the standard black hole central engine models for GRBs, an...

  20. The Fermi Gamma-ray Burst Monitor (GBM) Terrestrial Gamma-ray Flash (TGF) Catalog

    Science.gov (United States)

    Stanbro, M.; Briggs, M. S.; Roberts, O.; McBreen, S.; Bhat, N.; Fitzpatrick, G.

    2015-12-01

    We present results from the catalog of Terrestrial Gamma-ray Flashes (TGFs) detected with the Gamma-ray Burst Monitor (GBM) on the Fermi Gamma-ray Space Telescope. The first release, in January 2015, provided data on 2700 TGFs. Updates are extending the catalog at a rate of ~800 TGFs per year. The TGF sample is reliable, with cosmic rays rejected using data both from Fermi GBM and from the Large Area Telescope on Fermi. The online catalog include times (UTC and solar), spacecraft geographic positions, durations, count intensities and other Bayesian Block durations. The catalog includes separate tables for bright TGFs detected by the flight software and for Terrestrial Electron Beams (TEBs). In January 2016 additional data will be released online from correlating these TGFs with sferics detected by the World Wide Lightning Location Network (WWLLN). Maps of sferics in the vicinity of each TGF will be provided, as will the locations and times of sferics found to be associated with TGFs.

  1. Development of irradiator {sup 60}Co sources

    Energy Technology Data Exchange (ETDEWEB)

    Mosca, Rodrigo C.; Moura, Eduardo S.; Zeituni, Carlos A.; Mathor, Monica B., E-mail: rcmosca@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    According to a recent report by the International Agency for Research on Cancer (IARC) / WHO (2008-2010), the global impact of cancer more than doubled in 30 years. In this report, it was estimated that occurred about 12 million new cancer cases and 7 million deaths. In Brazil in 2010, with estimates for the year 2011, point to the occurrence of 489,270 new cases of cancer. Among the possibilities for cancer treatment, radiotherapy is one of the most important therapeutic and resources used to combat it. However, inherent complications of treatment can occur such as tiredness, loss of appetite, radiodermatitis and in more extreme cases late radionecrosis. In order to reproduce a point of radionecrosis in the vicinity of radiodermatitis to mimic these effects in animals, producing a model for assessment of tissue repair, we propose the setting up of an irradiator source of collimated {sup 60}Co. The development of was based on 11 sources of {sup 60}Co with 1 mm thickness that were inserted by inference in stainless steel 'gate-source' screw (patent pending) and later adjusted in a cross-shaped arrangement reinforced so that the beam radiation is directed to a target point, saving for other regions around this target point. The main use of this irradiator with sources of {sup 60}Co is just one cause radionecrosis point (target point) of approximately 5 mm{sup 2} with a surrounding and adjacent area of radiodermatitis around about 8 to 10 mm{sup 2} in laboratory animals for subsequent coating with epidermal-dermal matrix populated by a cell culture of human fibroblasts, keratinocytes and mesenchymal stem cells. With that said, its use will be valuable for evaluation of curative treatments against the bone and radionecrosis or palliative treatment rather than as it is currently assumed. (author)

  2. Real-time airborne gamma-ray background estimation using NASVD with MLE and radiation transport for calibration

    International Nuclear Information System (INIS)

    Helicopter-mounted gamma-ray detectors can provide law enforcement officials the means to quickly and accurately detect, identify, and locate radiological threats over a wide geographical area. The ability to accurately distinguish radiological threat-generated gamma-ray signatures from background gamma radiation in real time is essential in order to realize this potential. This problem is non-trivial, especially in urban environments for which the background may change very rapidly during flight. This exacerbates the challenge of estimating background due to the poor counting statistics inherent in real-time airborne gamma-ray spectroscopy measurements. To address this challenge, we have developed a new technique for real-time estimation of background gamma radiation from aerial measurements without the need for human analyst intervention. The method can be calibrated using radiation transport simulations along with data from previous flights over areas for which the isotopic composition need not be known. Over the examined measured and simulated data sets, the method generated accurate background estimates even in the presence of a strong, 60Co source. The potential to track large and abrupt changes in background spectral shape and magnitude was demonstrated. The method can be implemented fairly easily in most modern computing languages and environments

  3. Real-time airborne gamma-ray background estimation using NASVD with MLE and radiation transport for calibration

    Science.gov (United States)

    Kulisek, J. A.; Schweppe, J. E.; Stave, S. C.; Bernacki, B. E.; Jordan, D. V.; Stewart, T. N.; Seifert, C. E.; Kernan, W. J.

    2015-06-01

    Helicopter-mounted gamma-ray detectors can provide law enforcement officials the means to quickly and accurately detect, identify, and locate radiological threats over a wide geographical area. The ability to accurately distinguish radiological threat-generated gamma-ray signatures from background gamma radiation in real time is essential in order to realize this potential. This problem is non-trivial, especially in urban environments for which the background may change very rapidly during flight. This exacerbates the challenge of estimating background due to the poor counting statistics inherent in real-time airborne gamma-ray spectroscopy measurements. To address this challenge, we have developed a new technique for real-time estimation of background gamma radiation from aerial measurements without the need for human analyst intervention. The method can be calibrated using radiation transport simulations along with data from previous flights over areas for which the isotopic composition need not be known. Over the examined measured and simulated data sets, the method generated accurate background estimates even in the presence of a strong, 60Co source. The potential to track large and abrupt changes in background spectral shape and magnitude was demonstrated. The method can be implemented fairly easily in most modern computing languages and environments.

  4. The nature of the outflow in gamma-ray bursts

    CERN Document Server

    Kumar, P; Panaitescu, A; Willingale, R; O'Brien, P; Burrows, D; Cummings, J; Gehrels, N; Holland, S; Pandey, S B; Vanden Berk, D E; Zane, S

    2007-01-01

    The Swift satellite has enabled us to follow the evolution of gamma-ray burst (GRB) fireballs from the prompt gamma-ray emission to the afterglow phase. The early x-ray and optical data obtained by telescopes aboard the Swift satellite show that the source for prompt gamma-ray emission, the emission that heralds these bursts, is short lived and that its source is distinct from that of the ensuing, long-lived afterglow. Using these data, we determine the distance of the gamma-ray source from the center of the explosion. We find this distance to be 1e15-1e16 cm for most bursts and we show that this is within a factor of ten of the radius of the shock-heated circumstellar medium (CSM) producing the x-ray photons. Furthermore, using the early gamma-ray, x-ray and optical data, we show that the prompt gamma-ray emission cannot be produced in internal shocks, nor can it be produced in the external shock; in a more general sense gamma-ray generation mechanisms based on shock physics have problems explaining the GRB ...

  5. Models of X-ray and gamma-ray emission from Seyfert galaxies

    OpenAIRE

    Svensson, Roland

    1996-01-01

    X-ray and gamma-ray observations of Seyfert 1 galaxies are briefly reviewed. Both thermal and non-thermal model for X-ray and gamma-ray emission are discussed. Particular attention is given to various disc-corona models including both homogeneous and inhomogeneous (patchy) corona models. Recent work on exact radiative transfer in such geometries are reviewed.

  6. The Supernova -- Gamma-Ray Burst Connection

    CERN Document Server

    Woosley, S E

    2006-01-01

    Observations show that at least some gamma-ray bursts (GRBs) happen simultaneously with core-collapse supernovae (SNe), thus linking by a common thread nature's two grandest explosions. We review here the growing evidence for and theoretical implications of this association, and conclude that most long-duration soft-spectrum GRBs are accompanied by massive stellar explosions (GRB-SNe). The kinetic energy and luminosity of well-studied GRB-SNe appear to be greater than those of ordinary SNe, but evidence exists, even in a limited sample, for considerable diversity. The existing sample also suggests that most of the energy in the explosion is contained in nonrelativistic ejecta (producing the supernova) rather than in the relativistic jets responsible for making the burst and its afterglow. Neither all SNe, nor even all SNe of Type Ibc produce GRBs. The degree of differential rotation in the collapsing iron core of massive stars when they die may be what makes the difference.

  7. Gamma-ray bursts and cosmology.

    Science.gov (United States)

    Lamb, D Q

    2007-05-15

    I review the current status of the use of gamma-ray bursts (GRBs) as probes of the early Universe and cosmology. I describe the promise of long GRBs as probes of the high redshift (z>4) and very high redshift (z>5) Universe, and several key scientific results that have come from observations made possible by accurate, rapid localizations of these bursts by Swift. I then estimate the fraction of long GRBs that lie at very high redshifts and discuss ways in which it may be possible to rapidly identify-and therefore study-a larger number of these bursts. Finally, I discuss the ways in which both long and short GRBs can be made 'standard candles' and used to constrain the properties of dark energy. PMID:17301023

  8. The Gamma Ray Bursts Hubble diagram

    CERN Document Server

    Capozziello, S; Dainotti, M G; De Laurentis, M; Izzo, L; Perillo, M

    2011-01-01

    Thanks to their enormous energy release, Gamma Rays Bursts (GRBs) have recently attracted a lot of interest to probe the Hubble diagram (HD) deep into the matter dominated era and hence complement Type Ia Supernovae (SNeIa). We consider here three different calibration methods based on the use of a fiducial LCDM model, on cosmographic parameters and on the local regression on SNeIa to calibrate the scaling relations proposed as an equivalent to the Phillips law to standardize GRBs finding any significant dependence. We then investigate the evolution of these parameters with the redshift to obtain any statistical improvement. Under this assumption, we then consider possible systematics effects on the HDs introduced by the calibration method, the averaging procedure and the homogeneity of the sample arguing against any significant bias.

  9. Digital Logarithmic Airborne Gamma Ray Spectrometer

    CERN Document Server

    Zeng, GuoQiang; Li, Chen; Tan, ChengJun; Ge, LiangQuan; Gu, Yi; Cheng, Feng

    2014-01-01

    A new digital logarithmic airborne gamma ray spectrometer is designed in this study. The spectrometer adopts a high-speed and high-accuracy logarithmic amplifier (LOG114) to amplify the pulse signal logarithmically and to improve the utilization of the ADC dynamic range, because the low-energy pulse signal has a larger gain than the high-energy pulse signal. The spectrometer can clearly distinguish the photopeaks at 239, 352, 583, and 609keV in the low-energy spectral sections after the energy calibration. The photopeak energy resolution of 137Cs improves to 6.75% from the original 7.8%. Furthermore, the energy resolution of three photopeaks, namely, K, U, and Th, is maintained, and the overall stability of the energy spectrum is increased through potassium peak spectrum stabilization. Thus, effectively measuring energy from 20keV to 10MeV is possible.

  10. Modulation of gamma ray induced chromosome aberrations in human peripheral blood lymphocytes by Hippophae rhammnoides leaf extract, SBL-1

    International Nuclear Information System (INIS)

    Hippophae rhammnoides L. commonly known as seabuckthorn is a temperate shrub and native of Asia and Europe. It has high antioxidant potential and is known to the traditional Indian, Chinese and Tibetan medicinal system for treatment of multiple disorders viz., circulatory and digestive disorders, hepatic injuries, neoplasia etc. One time treatment with the standardized leaf extract from H. rhammnoides (SBL-1) before whole body irradiation with 60Co (10 Gy), rendered more than 90% survival in non SBL-1 treated irradiated animals (J herbs, spices medi plants, 2009). Present study investigated the effects of SBL-1 treatment on chromosomal damage in human peripheral blood lymphocytes (PBL), with or without 60Co-gamma-radiation. The lymphocytes were isolated from the blood drawn from different donors. The isolated lymphocytes were divided into several groups: Group 1-untreated control, Group 2-irradiated (2 Gy), Group 3, 4 and 5 were treated with different concentration of SBL-1, 30 min. after irradiation with 60Co-gamma-rays (2 Gy). Group 6 was treated with the maximum concentration of SBL-1 used in the study. The metaphase spreading technique was used as per standard procedure to record chromosome breaks, dicentrics, acentrics and rings. The results were also recorded in terms of total aberrant metaphase and frequency of aberrant metaphase per 100 cells. In comparison to the untreated control, in the irradiated PBL culture, there was 8-fold increase in breaks, 211-folds in dicentrics, 75-folds in acentrics and 3-folds in rings (average data). SBL-1 alone at the highest concentration did not cause any significant change in number of breaks, dicentrics, acentrics and rings. The radiation induced aberrations decreased significantly by treatment with SBL-1 and the maximum decrease was observed when the cells were treated with 22μg/ml of SBL-1. These results demonstrated the anti-clastogenic activity of SBL-1 against gamma radiation induced damage. (author)

  11. Hand-held high resolution gamma ray spectrometer

    International Nuclear Information System (INIS)

    A fully portable and a semi-portable high resolution gamma spectrometer are described. These instruments have the resolving capabilities that are inherent to germanium spectrometers and have the portability needed for health physics. The instruments are usable as a gamma-ray or x-ray fluorescence spectrometer

  12. Review of GRANAT observations of gamma-ray bursts

    DEFF Research Database (Denmark)

    Terekhov, O.; Denissenko, D.; Sunyaev, R.;

    1995-01-01

    The GRANAT observatory was launched into a high apogee orbit on 1 December, 1989. Three instruments onboard GRANAT - PHEBUS, WATCH and SIGMA are able to detect gamma-ray bursts in a very broad energy range from 6 keV up to 100 MeV. Over 250 gamma-ray bursts were detected. We discuss the results o...

  13. Gamma Rays from Star Formation in Clusters of Galaxies

    CERN Document Server

    Storm, Emma; Profumo, Stefano

    2012-01-01

    Star formation in galaxies is observed to be associated with gamma-ray emission. The detection of gamma rays from star-forming galaxies by the Fermi Large Area Telescope (LAT) has allowed the determination of a functional relationship between star formation rate and gamma-ray luminosity (Ackermann et. al. 2012). Since star formation is known to scale with total infrared (8-1000 micrometers) and radio (1.4 GHz) luminosity, the observed infrared and radio emission from a star-forming galaxy can be used to quantitatively infer the galaxy's gamma-ray luminosity. Similarly, star forming galaxies within galaxy clusters allow us to derive lower limits on the gamma-ray emission from clusters, which have not yet been conclusively detected in gamma rays. In this study we apply the relationships between gamma-ray luminosity and radio and IR luminosities derived in Ackermann et. al. 2012 to a sample of galaxy clusters from Ackermann et. al. 2010 in order to place lower limits on the gamma-ray emission associated with sta...

  14. Wolf-Rayet stars as gamma-ray burst progenitors

    NARCIS (Netherlands)

    Langer, N.; van Marle, A. -J; Yoon, S.C.

    2010-01-01

    It became clear in the last few years that long gamma-ray bursts are associated with the endpoints of massive star evolution. They occur in star forming regions at cosmological distances (Jakobsson et al., 2005), and are associated with supernova-type energies. The collapsar model explains gamma-ray

  15. A new processing technique for airborne gamma-ray data

    DEFF Research Database (Denmark)

    Hovgaard, Jens

    1997-01-01

    The mathematical-statistical background for at new technique for processing gamma-ray spectra is presented. The technique - Noise Adjusted Singular Value Decomposition - decomposes at set of gamma-ray spectra into a few basic spectra - the spectral components. The spectral components can be proce...

  16. The Gamma-Ray Luminosity Function of Radio Pulsars

    Science.gov (United States)

    Helfand, David J.

    1998-01-01

    This final report is a study of gamma-ray luminosity function of radio pulsars. The goal is to constrain certain parameters in order to address such diverse issues as the high energy emission mechanism in pulsars and the fraction of the Galaxy's gamma ray emission attributable to these objects.

  17. Very High Energy Gamma Ray Extension of GRO Observations

    Science.gov (United States)

    Weekes, Trevor C.

    1994-01-01

    The membership, progress, and invited talks, publications, and proceedings made by the Whipple Gamma Ray Collaboration is reported for june 1990 through May 1994. Progress was made in the following areas: the May 1994 Markarian Flare at Whipple and EGRET (Energetic Gamma Ray Experiment Telescope) energies; AGN's (Active Galactic Nuclei); bursts; supernova remnants; and simulations and energy spectra.

  18. Supernova sheds light on gamma-ray bursts

    CERN Multimedia

    2003-01-01

    On 29 March the HETE-II satellite detected the most violent explosion in the universe to date - an enormous burst of gamma rays. Observers across the world recorded and studied the event. It appears to prove that gamma ray bursts originate in supernovae (1 page)

  19. The University of Durham Mark 6 $\\gamma$ Ray Telescope

    CERN Document Server

    Armstrong, P; Cottle, P J; Dickinson, J E; Dickinson, M R; Dipper, N A; Hilton, S E; Hogg, W R; Holder, J; Kendall, T R; McComb, T J L; Moore, C M; Orford, K J; Rayner, S M; Roberts, I D; Roberts, M D; Robertshaw, M; Shaw, S E; Tindale, K; Tummey, S P; Turver, K E

    1997-01-01

    The design, construction and operation of the University of Durham ground-based gamma ray telescope is discussed. The telescope has been designed to detect gamma rays in the 300 GeV). The telescope was commissioned in 1995 and a description of its design and operation is presented, together with a verification of the telescope's performance

  20. A Search for Gamma-Ray Bursts and Pulsars, and the Application of Kalman Filters to Gamma-Ray Reconstruction

    CERN Document Server

    Jones, B B

    2002-01-01

    Part I describes the analysis of periodic and transient signals in EGRET data. A method to search for the transient flux from gamma-ray bursts independent of triggers from other gamma-ray instruments is developed. Several known gamma-ray bursts were independently detected, and there is evidence for a previously unknown gamma-ray burst candidate. Statistical methods using maximum likelihood and Bayesian inference are developed and implemented to extract periodic signals from gamma-ray sources in the presence of significant astrophysical background radiation. The analysis was performed on six pulsars and three pulsar candidates. The three brightest pulsars, Crab, Vela, and Geminga, were readily identified, and would have been detected independently in the EGRET data without knowledge of the pulse period. No significant pulsation was detected in the three pulsar candidates. Eighteen X-ray binaries were examined. None showed any evidence of periodicity. In addition, methods for calculating the detection threshold...

  1. A directional gamma-ray detector based on scintillator plates

    Energy Technology Data Exchange (ETDEWEB)

    Hanna, D., E-mail: hanna@physics.mcgill.ca; Sagnières, L.; Boyle, P.J.; MacLeod, A.M.L.

    2015-10-11

    A simple device for determining the azimuthal location of a source of gamma radiation, using ideas from astrophysical gamma-ray burst detection, is described. A compact and robust detector built from eight identical modules, each comprising a plate of CsI(Tl) scintillator coupled to a photomultiplier tube, can locate a point source of gamma rays with degree-scale precision by comparing the count rates in the different modules. Sensitivity to uniform environmental background is minimal.

  2. Gamma ray analysis of multi-component material

    International Nuclear Information System (INIS)

    A method and apparatus is disclosed for analyzing a multi-component material having at least three components using gamma radiation having at least two different energies. Upon irradiation of at least a sample of material, the multi-energy gamma rays which are propagated through the sample are detected. The intensity of the detected gamma rays is measured and the amount of at least one of the components of the material is determined by solving a set of simultaneous equations. (author)

  3. Muon Detection of TeV $\\gamma$ Rays from $\\gamma$ Ray Bursts

    CERN Document Server

    Alvarez-Muñiz, J

    1999-01-01

    Because of the limited size of the satellite-borne instruments, it has not been possible to observe the flux of gamma ray bursts (GRB) beyond GeV energy. We here show that it is possible to detect the GRB radiation of TeV energy and above, by detecting the muon secondaries produced when the gamma rays shower in the Earth's atmosphere. Observation is made possible by the recent commissioning of underground detectors (AMANDA, the Lake Baikal detector and MILAGRO) which combine a low muon threshold of a few hundred GeV or less, with a large effective area of 10^3 m^2 or more. Observations will not only provide new insights in the origin and characteristics of GRB, they also provide quantitative information on the diffuse infrared background.

  4. 60Coγ射线半身照射对非照射区域骨髓造血组织基质细胞衍生因子1表达的影响%Influences of 60Coγray irradiation on expression stromal cell derived factor-1 in bone marrow hematopoietic tissue of non-irradiation area in left-half-body ionizing irradiated mice

    Institute of Scientific and Technical Information of China (English)

    高作文; 杨龙; 陈乐如; 娄金书; 张国强; 李开信; 程天民

    2013-01-01

    Objective To invesligale the mouse bone marrow hemalopoielic functions in non-irradiation area after irradiated by way of left-half- body. Methods The 6-8-week male Kunming strain mice were randomly divided into normal control( NC) , total-body-irradiated( TBI) , left-half-body-irradiated( LHBI) , and total-body-shield-irradia-ted( TBSI) groups. Left-half-body-irradiated group was treated with two pieces of 5 cm x 8 cm x 16 cm overlapped lead bricks shielding right-side body and irradiated with 8. 0 Gy60Coγ-ray. The leukocyte in peripheral blood and the number of bone marrow hematopoietic cells( BMHCs) were studied, the concentration of SOD, MDA in mouse serum were measured, and the expression SDF-1 in bone marrow hematopoietic tissues were observed by the Western blotting method and laser scanning confocal microscope combined with immunohistochemistry. Results In the left-half-body irradiated condition, the leucocyte in peripheral blood and the BMHCs were diminished, the concentration of MDA was increased and the SOD was decreased in the mouse serum remarkably ( compared with NC, P <0. 01) ; In non-irradiation area, the SDF-1-positive cells and the expression SDF-1 in bone marrow hematopoietic tissues were reduced significantly. Conclusion Our study suggested that the local irradiation resulted in the decrease of SDF-1-positive cells and the decline expression SDF-1 in bone marrow hematopoietic tissues in non-irradiation area, and the increase of reactive oxygen or free radicals might play an important role in the abnormal expression of SDF-1 in BMHT and the injury of hematopoietic microenvironment.%目的 探讨局部电离辐射对小鼠非照射区域骨髓造血组织基质细胞衍生因子-1(SDF-1)表达的影响.方法 将6~8周龄雄性昆明小鼠随机分为健康对照组、全身照射组、全身屏蔽照射组以及左半身照射组4组,用铅屏蔽建立半身照射模型,以8.0 Gy 60Co γ射线照射,观察小鼠外周血白细胞和骨髓有核

  5. Extragalactic Gamma Ray Excess from Coma Supercluster Direction

    Indian Academy of Sciences (India)

    Pantea Davoudifar; S. Jalil Fatemi

    2011-09-01

    The origin of extragalactic diffuse gamma ray is not accurately known, especially because our suggestions are related to many models that need to be considered either to compute the galactic diffuse gamma ray intensity or to consider the contribution of other extragalactic structures while surveying a specific portion of the sky. More precise analysis of EGRET data however, makes it possible to estimate the diffuse gamma ray in Coma supercluster (i.e., Coma\\A1367 supercluster) direction with a value of ( > 30MeV) ≃ 1.9 × 10-6 cm-2 s-1, which is considered to be an upper limit for the diffuse gamma ray due to Coma supercluster. The related total intensity (on average) is calculated to be ∼ 5% of the actual diffuse extragalactic background. The calculated intensity makes it possible to estimate the origin of extragalactic diffuse gamma ray.

  6. Gamma-rays as probes of the Universe

    CERN Document Server

    Horns, Dieter

    2016-01-01

    The propagation of $\\gamma$ rays over very large distances provides new insights on the intergalactic medium and on fundamental physics. On their path to the Earth, $\\gamma$ rays can annihilate with diffuse infrared or optical photons of the intergalactic medium, producing $e^+ \\, e^-$ pairs. The density of these photons is poorly determined by direct measurements due to significant galactic foregrounds. Studying the absorption of $\\gamma$ rays from extragalactic sources at different distances allows the density of low-energy diffuse photons to be measured. Gamma-ray propagation may also be affected by new phenomena predicted by extensions of the Standard Model of particle physics. Lorentz Invariance is violated in some models of Quantum Gravity, leading to an energy-dependent speed of light in vacuum. From differential time-of-flight measurements of the most distant $\\gamma$-ray bursts and of flaring active galactic nuclei, lower bounds have been set on the energy scale of Quantum Gravity. Another effect tha...

  7. Gamma-ray Explosion in Multiple Compton Scattering Regime

    CERN Document Server

    Gong, Z; Shou, Y R; Qiao, B; Bulanov, S V; Esirkepov, T Zh; Bulanov, S S; Chen, C E; He, X T; Yan, X Q

    2016-01-01

    Gamma-ray explosion from near critical density (NCD) target irradiated by four symmetrical imploding laser pulses is numerically investigated. With peak intensities about $10^{23}$ W/cm$^2$, the laser pulses boost electron energy through direct laser acceleration, while pushing them inward with the ponderomotive force. After backscattering with counter-propagating laser, the accelerated electron will be trapped in the optical lattice or the electromagnetic standing waves (SW) created by the coherent overlapping of the laser pulses, and meanwhile emit gamma-ray photon in Multiple Compton Scattering regime, where electron acts as a medium to transfer energy from laser to gamma-ray. The energy conversion rate from laser pulses to gamma-ray can be as high as around 50\\%. It may become one of the most efficient gamma-ray sources in laboratory.

  8. The supernova-gamma-ray burst-jet connection.

    Science.gov (United States)

    Hjorth, Jens

    2013-06-13

    The observed association between supernovae and gamma-ray bursts represents a cornerstone in our understanding of the nature of gamma-ray bursts. The collapsar model provides a theoretical framework for this connection. A key element is the launch of a bipolar jet (seen as a gamma-ray burst). The resulting hot cocoon disrupts the star, whereas the (56)Ni produced gives rise to radioactive heating of the ejecta, seen as a supernova. In this discussion paper, I summarize the observational status of the supernova-gamma-ray burst connection in the context of the 'engine' picture of jet-driven supernovae and highlight SN 2012bz/GRB 120422A--with its luminous supernova but intermediate high-energy luminosity--as a possible transition object between low-luminosity and jet gamma-ray bursts. The jet channel for supernova explosions may provide new insights into supernova explosions in general. PMID:23630379

  9. Solar gamma-ray lines and interplanetary solar protons

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimori, M.

    1985-03-01

    Solar gamma-ray lines and protons were simultaneously observed for six flares on April 1, 4, and 27, 1981, May 13, 1981, February 1, 1982, and June 6, 1982 by the Hinotori and Himawari satellites. The flare list is presented, and the time histories of gamma-rays and protons are shown. The relationship between the gamma-ray line fluences and peak proton fluxes for these flares does not reveal an apparent correlation between them. The present results imply that the protons producing gamma-ray lines in the flare region, and protons observed near the earth, do not always belong to the same population, and favor the downward streaming model for the gamma-ray line production. 15 references.

  10. Solar gamma-ray lines and interplanetary solar protons

    Science.gov (United States)

    Yoshimori, M.

    1985-03-01

    Solar gamma-ray lines and protons were simultaneously observed for six flares on April 1, 4, and 27, 1981, May 13, 1981, February 1, 1982, and June 6, 1982 by the Hinotori and Himawari satellites. The flare list is presented, and the time histories of gamma-rays and protons are shown. The relationship between the gamma-ray line fluences and peak proton fluxes for these flares does not reveal an apparent correlation between them. The present results imply that the protons producing gamma-ray lines in the flare region, and protons observed near the earth, do not always belong to the same population, and favor the downward streaming model for the gamma-ray line production.

  11. Effect of Conversion Efficiency on Gamma-Ray Burst Energy

    Institute of Scientific and Technical Information of China (English)

    Lei Xu; Zi-Gao Dai

    2004-01-01

    Beaming effect makes it possible that gamma-ray bursts have a standard energy,but the gamma-ray energy release is sensitive to some parameters.Our attention is focused on the effect of the gamma ray conversion efficiency(ηγ),which may range between 0.01 and 0.9,and which probably has a random value for different GRBs under certain conditions.Making use of the afterglow data from the literature,we carried out a complete correction to the conical opening angle formula.Within the framework of the conical jet model,we ran a simple Monte Carlo simulation for random values of ηγ,and found that the gamma-ray energy release is narrowly clustered,whether we use a constant value of ηγ or random values for different gamma-ray bursts.

  12. Sorption of {sup 60} Co on inorganic solids; Sorcion de {sup 60} Co en solidos inorganicos

    Energy Technology Data Exchange (ETDEWEB)

    Granados C, F.; Bulbulian G, S. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Mardel V, B. [UAM-I, 09340 Mexico D.F. (Mexico)

    2003-07-01

    The behavior of sorption of the {sup 60} Co in aqueous solution under static conditions to different values of pH of the aqueous solution (1, 3, 5, 7, and 10) on MgO, MnO{sub 2}, SnO, TiO{sub 2}, activated carbon and calcinate hydrotalcite was investigated. It was found that the best sorbents of the {sup 60} Co was the MnO{sub 2}, activated carbon and TiO{sub 2} whose sorption was incremented when increasing the pH value of the aqueous solutions, in the one case of the hydrated oxides, the {sup 60} Co interacted with the electrically charged surface of the sorbents that depends on the pH of the solution and of the point of zero charge (zpc) of the sorbent. (Author)

  13. Search for Sub-TeV Gamma Rays Coincident with BATSE Gamma Ray Bursts

    CERN Document Server

    Poirier, J; Gress, J; Race, D

    2003-01-01

    Project GRAND is a 100m x 100m air shower array of proportional wire chambers (PWCs). There are 64 stations each with eight 1.29 m^2 PWC planes arranged in four orthogonal pairs placed vertically above one another to geometrically measure the angles of charged secondaries. A steel plate above the bottom pair of PWCs differentiates muons (which pass undeflected through the steel) from non-penetrating particles. FLUKA Monte Carlo studies show that a TeV gamma ray striking the atmosphere at normal incidence produces 0.23 muons which reach ground level where their angles and identities are measured. Thus, paradoxically, secondary muons are used as a signature for gamma ray primaries. The data are examined for possible angular and time coincidences with eight gamma ray bursts (GRBs) detected by BATSE. Seven of the GRBs were selected because of their good acceptance by GRAND and high BATSE Fluence. The eighth GRB was added due to its possible coincident detection by Milagrito. For each of the eight candidate GRBs, ...

  14. Blueshifting may explain the gamma ray bursts

    CERN Document Server

    Krasiński, Andrzej

    2015-01-01

    It is shown that the basic observed properties of the gamma-ray bursts (GRBs) are accounted for if one assumes that the GRBs arise by blueshifting the emission radiation of hydrogen and helium generated during the last scattering epoch. The blueshift generator for a single GRB is a Lema\\^{\\i}tre -- Tolman (L--T) region with a nonconstant bang-time function $t_B(r)$ matched into a Friedmann background. Blueshift visible to the observer arises \\textit{only on radial rays} that are emitted in the L--T region. The paper presents three L--T models with different Big Bang profiles, adapted for the highest and the lowest end of the GRB frequency range. The models account for: (1) The observed frequency range of the GRBs; (2) Their limited duration; (3) The afterglows; (4) Their hypothetical collimation into narrow jets; (5) The large distances to their sources; (6) The multitude of the observed GRBs. Properties (2), (3) and (6) are accounted for only qualitatively. With a small correction of the parameters of the mo...

  15. An updated Gamma Ray Bursts Hubble diagram

    CERN Document Server

    Cardone, V F; Dainotti, M G

    2009-01-01

    Gamma ray bursts (GRBs) have recently attracted much attention as a possible way to extend the Hubble diagram to very high redshift. To this aim, the luminosity (or isotropic emitted energy) of a GRB at redshift z must be evaluated from a correlation with a distance independent quantity so that one can then solve for the luminosity distance D_L(z) and hence the distance modulus mu(z). Averaging over five different two parameters correlations and using a fiducial cosmological model to calibrate them, Schaefer (2007) has compiled a sample of 69 GRBs with measured mu(z) which has since then been widely used to constrain cosmological parameters. We update here that sample by many aspects. First, we add a recently found correlation for the X - ray afterglow and use a Bayesian inspired fitting method to calibrate the different GRBs correlations known insofar assuming a fiducial LCDM model in agreement with the recent WMAP5 data. Averaging over six correlations, we end with a new GRBs Hubble diagram comprising 83 ob...

  16. $\\gamma$-Ray Bursts and Related Phenomena

    CERN Document Server

    Piran, T

    1999-01-01

    Gamma-ray bursts (GRBs) have puzzled astronomers since their accidental discovery in the sixties. The BATSE detector on the COMPTON-GRO satellite has been detecting one burst per day for the last six years. Its findings have revolutionized our ideas about the nature of these objects. They have shown that GRBs are at cosmological distances. This idea was accepted with difficulties at first. However, the recent discovery of an x-ray afterglow by the Italian/Dutch satellite BeppoSAX led to a detection of high red-shift absorption lines in the optical afterglow of GRB970508 and to a confirmation of its cosmological origin. The simplest and practically inevitable interpretation of these observations is that GRBs result from the conversion of the kinetic energy of ultra-relativistic particles flux to radiation in an optically thin region. The "inner engine" that accelerates the particles or generates the Poynting flux is hidden from direct observations. Recent studies suggest the ``internal-external'' model: intern...

  17. The SVOM gamma-ray burst mission

    CERN Document Server

    Cordier, B; Atteia, J -L; Basa, S; Claret, A; Daigne, F; Deng, J; Dong, Y; Godet, O; Goldwurm, A; Götz, D; Han, X; Klotz, A; Lachaud, C; Osborne, J; Qiu, Y; Schanne, S; Wu, B; Wang, J; Wu, C; Xin, L; Zhang, B; Zhang, S -N

    2015-01-01

    We briefly present the science capabilities, the instruments, the operations, and the expected performance of the SVOM mission. SVOM (Space-based multiband astronomical Variable Objects Monitor) is a Chinese-French space mission dedicated to the study of Gamma-Ray Bursts (GRBs) in the next decade. The SVOM mission encompasses a satellite carrying four instruments to detect and localize the prompt GRB emission and measure the evolution of the afterglow in the visible band and in X-rays, a VHF communication system enabling the fast transmission of SVOM alerts to the ground, and a ground segment including a wide angle camera and two follow-up telescopes. The pointing strategy of the satellite has been optimized to favor the detection of GRBs located in the night hemisphere. This strategy enables the study of the optical emission in the first minutes after the GRB with robotic observatories and the early spectroscopy of the optical afterglow with large telescopes to measure the redshifts. The study of GRBs in the...

  18. Gamma-Ray Bursts 2012 Conference

    Science.gov (United States)

    It is a pleasure to announce the next combined Fermi/Swift GRB conference covering recent advances in all aspects of gamma-ray burst observations and theory. This conference will be held in Munich, Germany, on 7-11 May 2012, and follows similar previous combined Fermi/Swift meetings in Huntsville (Oct. 2008) and Annapolis (Nov. 2010). Gamma-ray bursts are the most energetic explosions in the Universe and are thought to be the birth signatures of black holes. This is an exciting time in the GRB field as various missions provide a wealth of new data on this still puzzling phenomenon. The Fermi misson provides unprecedented spectral coverage over 7 decades in energy, and among others discovered new spectral components which challenge our standard picture of the prompt emission. The Swift mission continuous to swiftly monitor and locate GRBs in multiple wavebands, providing the basis for all ground-based follow-up observations towards redshift measurements and afterglow and host property investigations. AGILE, INTEGRAL, Suzaku and Konus continue to provide crucial information on GRB properties, and the MAXI mission provides an all sky X-ray monitoring of transients. There is also growing capability for follow-up observations by ground-based telescopes at basically all wavelengths. Besides the classical optical/infrared/radio observations, searches are underway for TeV emission, neutrinos and gravitational waves. Moreover, new experiments are expected to have returned first data, among others POGO on the prompt polarization properties, UFFO on very early optical emission, or ALMA on sub-millimeter properties. And last but not least, the unexpected is bringing us child-like astonishments at least once per year with a "GRB-trigger" which turns out to be not related to GRBs. Complementing all these new observational results, a huge theoretical effort is underway to understand the GRB phenomenon and keep up with the constant new puzzles coming from the data. This conference

  19. Seed germination of peanuts irradiated with cobalt (60CO)

    International Nuclear Information System (INIS)

    This work was realized to evaluate the effect of gamma irradiation (60Co) at doses 0, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00 and 4.00 kGy, on germination of seeds of peanut, cultivar BR1. Irradiation Department of Nuclear, UFPE, where he received after the irradiation, they were stored in packing of PET and polyethylene braided with a time of 90 days. Through the results, obtained monthly, concluded that the dose of 0.5 kGy was effective in the germination of seeds of peanut, not affecting its power of germination and overcoming the witness within 30 to 60 days. (author)

  20. Study on mutation induced effect of gamma ray and DES on black bean phaseolus vulgaris

    Energy Technology Data Exchange (ETDEWEB)

    Le Thi Dinh; Pham Le Ha; Nguyen Van Toan; Le Xuan Tham [Nuclear Research Institute, Radiobiology Department, Dalat (Viet Nam)

    2001-03-01

    The study on mutation induced effect of gamma ray and DES on black bean Phaseolus vulgaris was carried out at Radiobiology Department, Nuclear Research Institute of Dalat. Dry seeds of variety No.1847 - Bonita - Cuba in set of 13 black bean varieties were irradiated with gamma ray from {sup 60}Co source at dose range from 150 Gy to 350 Gy and treated with DES at concentration from 0.1% to 0.3% in 2 hours for experiments in laboratory. The doses of 200, 250, 300 Gy and concentration of 0.2% DES in 2 hours were selected to treat dry seeds for experiments on the field. In populations of M{sub 1} generation, the height, number of branches and fruits per plant, number of seeds per fruit were decreased with increasing of irradiation doses. In populations of M{sub 2} generation, individual variants in leaf shape, chlorophyll, short stem, dwarf, early maturity, flowering in very short time were obtained and selected in all treatment cases. Mutation frequency at dose of 300 Gy was higher than that in other treatment cases, but ratio of sterility is also largest. The mutant lines of early maturity and short stem with flowering in very short time are promised materials for further studies. (author)