Apparatus and method for detecting gamma radiation

DOEpatents

Sigg, Raymond A.

1994-01-01

A high efficiency radiation detector for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data.

[Induced thymus aging: radiation model and application perspective for low intensive laser radiation].

PubMed

Sevost'ianova, N N; Trofimov, A V; Lin'kova, N S; Poliakova, V O; Kvetnoĭ, I M

2010-01-01

The influence of gamma-radiation on morphofunctional state of thymus is rather like as natural thymus aging. However gamma-radiation model of thymus aging widely used to investigate geroprotectors has many shortcomings and limitations. Gamma-radiation can induce irreversible changes in thymus very often. These changes are more intensive in comparison with changes, which can be observed at natural thymus aging. Low intensive laser radiation can not destroy structure of thymus and its effects are rather like as natural thymus aging in comparison with gamma-radiation effects. There are many parameters of low intensive laser radiation, which can be changed to improve morphofunctional thymus characteristics in aging model. Using low intensive laser radiation in thymus aging model can be very perspective for investigations of aging immune system.

Measurement of background gamma radiation in the northern Marshall Islands.

PubMed

Bordner, Autumn S; Crosswell, Danielle A; Katz, Ainsley O; Shah, Jill T; Zhang, Catherine R; Nikolic-Hughes, Ivana; Hughes, Emlyn W; Ruderman, Malvin A

2016-06-21

We report measurements of background gamma radiation levels on six islands in the northern Marshall Islands (Enewetak, Medren, and Runit onEnewetak Atoll; Bikini and Nam on Bikini Atoll; and Rongelap on Rongelap Atoll). Measurable excess radiation could be expected from the decay of (137)Cs produced by the US nuclear testing program there from 1946 to 1958. These recordings are of relevance to safety of human habitation and resettlement. We find low levels of gamma radiation for the settled island of Enewetak [mean = 7.6 millirem/year (mrem/y) = 0.076 millisievert/year (mSv/y)], larger levels of gamma radiation for the island of Rongelap (mean = 19.8 mrem/y = 0.198 mSv/y), and relatively high gamma radiation on the island of Bikini (mean = 184 mrem/y = 1.84 mSv/y). Distributions of gamma radiation levels are provided, and hot spots are discussed. We provide interpolated maps for four islands (Enewetak, Medren, Bikini, and Rongelap), and make comparisons to control measurements performed on the island of Majuro in the southern Marshall Islands, measurements made in Central Park in New York City, and the standard agreed upon by the United States and the Republic of the Marshall Islands (RMI) governments (100 mrem/y = 1 mSv/y). External gamma radiation levels on Bikini Island significantly exceed this standard (P = <0.01), and external gamma radiation levels on the other islands are below the standard. To determine conclusively whether these islands are safe for habitation, radiation exposure through additional pathways such as food ingestion must be considered.

Measurement of background gamma radiation in the northern Marshall Islands

PubMed Central

Bordner, Autumn S.; Crosswell, Danielle A.; Katz, Ainsley O.; Shah, Jill T.; Zhang, Catherine R.; Nikolic-Hughes, Ivana; Hughes, Emlyn W.; Ruderman, Malvin A.

2016-01-01

We report measurements of background gamma radiation levels on six islands in the northern Marshall Islands (Enewetak, Medren, and Runit onEnewetak Atoll; Bikini and Nam on Bikini Atoll; and Rongelap on Rongelap Atoll). Measurable excess radiation could be expected from the decay of 137Cs produced by the US nuclear testing program there from 1946 to 1958. These recordings are of relevance to safety of human habitation and resettlement. We find low levels of gamma radiation for the settled island of Enewetak [mean = 7.6 millirem/year (mrem/y) = 0.076 millisievert/year (mSv/y)], larger levels of gamma radiation for the island of Rongelap (mean = 19.8 mrem/y = 0.198 mSv/y), and relatively high gamma radiation on the island of Bikini (mean = 184 mrem/y = 1.84 mSv/y). Distributions of gamma radiation levels are provided, and hot spots are discussed. We provide interpolated maps for four islands (Enewetak, Medren, Bikini, and Rongelap), and make comparisons to control measurements performed on the island of Majuro in the southern Marshall Islands, measurements made in Central Park in New York City, and the standard agreed upon by the United States and the Republic of the Marshall Islands (RMI) governments (100 mrem/y = 1 mSv/y). External gamma radiation levels on Bikini Island significantly exceed this standard (P = <<0.01), and external gamma radiation levels on the other islands are below the standard. To determine conclusively whether these islands are safe for habitation, radiation exposure through additional pathways such as food ingestion must be considered. PMID:27274073

Differential sensitivity of Chironomus and human hemoglobin to gamma radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaikwad, Pallavi S.; Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085; Panicker, Lata

Chironomus ramosus is known to tolerate high doses of gamma radiation exposure. Larvae of this insect possess more than 95% of hemoglobin (Hb) in its circulatory hemolymph. This is a comparative study to see effect of gamma radiation on Hb of Chironomus and humans, two evolutionarily diverse organisms one having extracellular and the other intracellular Hb respectively. Stability and integrity of Chironomus and human Hb to gamma radiation was compared using biophysical techniques like Dynamic Light Scattering (DLS), UV-visible spectroscopy, fluorescence spectrometry and CD spectroscopy after exposure of whole larvae, larval hemolymph, human peripheral blood, purified Chironomus and human Hb.more » Sequence- and structure-based bioinformatics methods were used to analyze the sequence and structural similarities or differences in the heme pockets of respective Hbs. Resistivity of Chironomus Hb to gamma radiation is remarkably higher than human Hb. Human Hb exhibited loss of heme iron at a relatively low dose of gamma radiation exposure as compared to Chironomus Hb. Unlike human Hb, the heme pocket of Chironomus Hb is rich in aromatic amino acids. Higher hydophobicity around heme pocket confers stability of Chironomus Hb compared to human Hb. Previously reported gamma radiation tolerance of Chironomus can be largely attributed to its evolutionarily ancient form of extracellular Hb as evident from the present study. -- Highlights: •Comparison of radiation tolerant Chironomus Hb and radiation sensitive Human Hb. •Amino acid composition of midge and human heme confer differential hydrophobicity. •Heme pocket of evolutionarily ancient midge Hb provide gamma radiation resistivity.« less

Gadolinium-doped water cerenkov-based neutron and high energy gamma-ray detector and radiation portal monitoring system

DOEpatents

Dazeley, Steven A; Svoboda, Robert C; Bernstein, Adam; Bowden, Nathaniel

2013-02-12

A water Cerenkov-based neutron and high energy gamma ray detector and radiation portal monitoring system using water doped with a Gadolinium (Gd)-based compound as the Cerenkov radiator. An optically opaque enclosure is provided surrounding a detection chamber filled with the Cerenkov radiator, and photomultipliers are optically connected to the detect Cerenkov radiation generated by the Cerenkov radiator from incident high energy gamma rays or gamma rays induced by neutron capture on the Gd of incident neutrons from a fission source. The PMT signals are then used to determine time correlations indicative of neutron multiplicity events characteristic of a fission source.

Apparatus and method for identification of matrix materials in which transuranic elements are embedded using thermal neutron capture gamma-ray emission

DOEpatents

Close, D.A.; Franks, L.A.; Kocimski, S.M.

1984-08-16

An invention is described that enables the quantitative simultaneous identification of the matrix materials in which fertile and fissile nuclides are embedded to be made along with the quantitative assay of the fertile and fissile materials. The invention also enables corrections for any absorption of neutrons by the matrix materials and by the measurement apparatus by the measurement of the prompt and delayed neutron flux emerging from a sample after the sample is interrogated by simultaneously applied neutrons and gamma radiation. High energy electrons are directed at a first target to produce gamma radiation. A second target receives the resulting pulsed gamma radiation and produces neutrons from the interaction with the gamma radiation. These neutrons are slowed by a moderator surrounding the sample and bathe the sample uniformly, generating second gamma radiation in the interaction. The gamma radiation is then resolved and quantitatively detected, providing a spectroscopic signature of the constituent elements contained in the matrix and in the materials within the vicinity of the sample. (LEW)

Development of an alpha/beta/gamma detector for radiation monitoring

NASA Astrophysics Data System (ADS)

Yamamoto, Seiichi; Hatazawa, Jun

2011-11-01

For radiation monitoring at the site of nuclear power plant accidents such as Fukushima Daiichi, radiation detectors not only for gamma photons but also for alpha and beta particles are needed because some nuclear fission products emit beta particles and gamma photons and some nuclear fuels contain plutonium that emits alpha particles. We developed a radiation detector that can simultaneously monitor alpha and beta particles and gamma photons for radiation monitoring. The detector consists of three-layered scintillators optically coupled to each other and coupled to a photomultiplier tube. The first layer, which is made of a thin plastic scintillator (decay time: 2.4 ns), detects alpha particles. The second layer, which is made of a thin Gd2SiO5 (GSO) scintillator with 1.5 mol.% Ce (decay time: 35 ns), detects beta particles. The third layer made of a thin GSO scintillator with 0.4 mol.% Ce (decay time: 70 ns) detects gamma photons. By using pulse shape discrimination, the count rates of these layers can be separated. With individual irradiation of alpha and beta particles and gamma photons, the count rate of the first layer represented the alpha particles, the second layer represented the beta particles, and the third layer represented the gamma photons. Even with simultaneous irradiation of the alpha and beta particles and the gamma photons, these three types of radiation can be individually monitored using correction for the gamma detection efficiency of the second and third layers. Our developed alpha, beta, and gamma detector is simple and will be useful for radiation monitoring, especially at nuclear power plant accident sites or other applications where the simultaneous measurements of alpha and beta particles and gamma photons are required.

Development of an alpha/beta/gamma detector for radiation monitoring.

PubMed

Yamamoto, Seiichi; Hatazawa, Jun

2011-11-01

For radiation monitoring at the site of nuclear power plant accidents such as Fukushima Daiichi, radiation detectors not only for gamma photons but also for alpha and beta particles are needed because some nuclear fission products emit beta particles and gamma photons and some nuclear fuels contain plutonium that emits alpha particles. We developed a radiation detector that can simultaneously monitor alpha and beta particles and gamma photons for radiation monitoring. The detector consists of three-layered scintillators optically coupled to each other and coupled to a photomultiplier tube. The first layer, which is made of a thin plastic scintillator (decay time: 2.4 ns), detects alpha particles. The second layer, which is made of a thin Gd(2)SiO(5) (GSO) scintillator with 1.5 mol.% Ce (decay time: 35 ns), detects beta particles. The third layer made of a thin GSO scintillator with 0.4 mol.% Ce (decay time: 70 ns) detects gamma photons. By using pulse shape discrimination, the count rates of these layers can be separated. With individual irradiation of alpha and beta particles and gamma photons, the count rate of the first layer represented the alpha particles, the second layer represented the beta particles, and the third layer represented the gamma photons. Even with simultaneous irradiation of the alpha and beta particles and the gamma photons, these three types of radiation can be individually monitored using correction for the gamma detection efficiency of the second and third layers. Our developed alpha, beta, and gamma detector is simple and will be useful for radiation monitoring, especially at nuclear power plant accident sites or other applications where the simultaneous measurements of alpha and beta particles and gamma photons are required. © 2011 American Institute of Physics

Apparatus and method for detecting gamma radiation

DOEpatents

Sigg, R.A.

1994-12-13

A high efficiency radiation detector is disclosed for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data. 4 figures.

Gamma ray astrophysics. [emphasizing processes and absorption

NASA Technical Reports Server (NTRS)

Stecker, F. W.

1974-01-01

Gamma ray production processes are reviewed, including Compton scattering, synchrotron radiation, bremsstrahlung interactions, meson decay, nucleon-antinucleon annihilations, and pion production. Gamma ray absorption mechanisms through interactions with radiation and with matter are discussed, along with redshifts and gamma ray fluxes.

Underwater radiation detector

DOEpatents

Kruse, Lyle W.; McKnight, Richard P.

1986-01-01

A detector apparatus for differentiating between gamma and neutron radiation is provided. The detector includes a pair of differentially shielded Geiger-Mueller tubes. The first tube is wrapped in silver foil and the second tube is wrapped in lead foil. Both the silver and lead foils allow the passage of gamma rays at a constant rate in a gamma ray only field. When neutrons are present, however, the silver activates and emits beta radiation that is also detected by the silver wrapped Geiger-Mueller tube while the radiation detected by the lead wrapped Geiger-Mueller tube remains constant. The amount of radiation impinging on the separate Geiger-Mueller tubes is then correlated in order to distinguish between the neutron and gamma radiations.

D/sup 0/*. -->. D/sup 0/. gamma. and other radiative decays of vector mesons. [SU-4 groups, decay widths

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bohm, A.; Teese, R.B.

1976-01-01

Using SU(4) as a spectrum generating group the radiative decay rates of the charmed vector mesons and of J(psi) are calculated. With the known decay rates of the old mesons GAMMA(..omega.. ..-->.. ..pi gamma..), GAMMA(phi ..-->.. eta ..gamma..), GAMMA(rho ..-->.. ..pi gamma..), GAMMA(K/sup 0/* ..-->.. K/sup 0/..gamma..) as input one obtains GAMMA(K/sup +/* ..-->.. K/sup +/..gamma..) = 2.6 keV, GAMMA(..omega.. ..-->.. eta ..gamma..) = 220 eV, GAMMA(rho ..-->.. eta ..gamma..) = 4.8 keV, GAMMA(psi ..-->.. chi ..gamma..) = 1.6 keV, GAMMA(D/sup 0/* ..-->.. D/sup 0/..gamma..) = 350 eV and GAMMA(D/sup +/* ..-->.. D/sup +/..gamma..) = 22 eV.

Gamma radiation field intensity meter

DOEpatents

Thacker, Louis H.

1994-01-01

A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode.

Gamma radiation field intensity meter

DOEpatents

Thacker, Louis H.

1995-01-01

A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode.

Gamma radiation field intensity meter

DOEpatents

Thacker, L.H.

1995-10-17

A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode. 4 figs.

Gamma radiation field intensity meter

DOEpatents

Thacker, L.H.

1994-08-16

A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode. 4 figs.

Physical principles of neutron-gamma materials monitoring

NASA Astrophysics Data System (ADS)

Pekarskii, G. Sh.

1986-03-01

The physical principles of secondary radiation methods in nondestructive testing are discussed. Among the techniques considered are: neutron activation analysis (NAA); the induced-radiation method; and quasialbedo recording of secondary gamma-radiation. Emphasis is given to the neutron-gamma method which consists of exposing test material to a neutron flux and recording the secondary gamma-radiation by means of a spectrometer. The limitations of the method in detecting local inhomogeneous defects (filled pores cracks, and inclusions) in metal layers and multicomponents materials are described, and some advantages of the method over NAA are discussed. Formulas are derived for estimating the optimum density of the gamma-ray flux which is received by the detector.

Physical principles of neutron-gamma materials monitoring

NASA Astrophysics Data System (ADS)

Pekarskii, G. Sh.

1985-07-01

The physical principles of secondary radiation methods in nondestructive testing are discussed. Among the techniques considered are: neutron activation analysis (NAA); the induced-radiation method; and quasialbedo recording of secondary gamma-radiation. Emphasis is given to the neutron-gamma method which consists of exposing test material to a neutron flux and recording the secondary gamma-radiation by means of a spectrometer. The limitations of the method in detecting local inhomogeneous defects (filled pores cracks, and inclusions) in metal layers and multicomponents materials are described, and some advantages of the method over NAA are discussed. Formulas are derived for estimating the optimum density of the gamma-ray flux which is received by the detector.

Effects of gamma radiation on the chromosomes of Gryllidae (orthoptera)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, H.C.; Kevan, D.K.; Vickery, V.R.

1972-12-01

BS>Six species if Gryllidae (orthoptera), Gryllus assimilis, G, Bim aculatus, G. pennsylvanicus, Acheta domesticus, Scapipedus marginatus, and Allonemobius allardi, were subjected to gamma radiation treatment (dosages varied from 1000 rads to 2446 rads) in order to induce chromosomal abnormalities. Gamma radiation was found to affect development, survival, and reproduction. Effects of gamma rays were similar in all of the species studied, but sensitivity varied between the different species. (auth)

Unraveling Fungal Radiation Resistance Regulatory Networks through the Genome-Wide Transcriptome and Genetic Analyses of Cryptococcus neoformans

PubMed Central

Jung, Kwang-Woo; Yang, Dong-Hoon; Kim, Min-Kyu; Seo, Ho Seong

2016-01-01

ABSTRACT The basidiomycetous fungus Cryptococcus neoformans has been known to be highly radiation resistant and has been found in fatal radioactive environments such as the damaged nuclear reactor at Chernobyl. To elucidate the mechanisms underlying the radiation resistance phenotype of C. neoformans, we identified genes affected by gamma radiation through genome-wide transcriptome analysis and characterized their functions. We found that genes involved in DNA damage repair systems were upregulated in response to gamma radiation. Particularly, deletion of recombinase RAD51 and two DNA-dependent ATPase genes, RAD54 and RDH54, increased cellular susceptibility to both gamma radiation and DNA-damaging agents. A variety of oxidative stress response genes were also upregulated. Among them, sulfiredoxin contributed to gamma radiation resistance in a peroxiredoxin/thioredoxin-independent manner. Furthermore, we found that genes involved in molecular chaperone expression, ubiquitination systems, and autophagy were induced, whereas genes involved in the biosynthesis of proteins and fatty acids/sterols were downregulated. Most importantly, we discovered a number of novel C. neoformans genes, the expression of which was modulated by gamma radiation exposure, and their deletion rendered cells susceptible to gamma radiation exposure, as well as DNA damage insults. Among these genes, we found that a unique transcription factor containing the basic leucine zipper domain, named Bdr1, served as a regulator of the gamma radiation resistance of C. neoformans by controlling expression of DNA repair genes, and its expression was regulated by the evolutionarily conserved DNA damage response protein kinase Rad53. Taken together, the current transcriptome and functional analyses contribute to the understanding of the unique molecular mechanism of the radiation-resistant fungus C. neoformans. PMID:27899501

RADIATION GENETICS IN WHEAT. VII. COMPARISON OF RADIATION EFFECTS OF BETA- AND GAMMA-RAYS ON DIPLOID WHEAT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsumura, S.

1962-01-01

Seeds of Triticum monococcum flavescens were soaked in P/sup 32/ and I/ sup 131/solutions for 2 days before sowing, to compare the effects of beta and gamma radiations. Radioactive solutions of pH 6-7 contained 0.05-0.8 mc/gr P/sup 32/ and 0.2--0.8 mc/g I/sup 131/. For comparison, seeds soaked in water for 2 days were exposed to gamma radiation with Co/sup 60/ at the dosages 2.5, 5, 10, and 20 kr. The growth of seedlings, height of mature plants, single-spike fertility, and chromosome aberrations of treated plants in X/sub 1/ and chlorophyll mutations in X/sub 2/ were compared for beta and gammamore » irradiation. The higher the dosage of beta and gamma rays, the more delayed were emergence and growth of seedlings and the lower were survival rate, height of mature plants, and fertility. The relation between the inhibition of seedling growth and dosage of beta and gamma radiations coincides roughly with that between the decrease of survival rate or- fertility and dosage. There was no emergence of seedlings at 20 kr gamma radiation and 0.8 mc/g P/sup 32/ beta radiation. The effects of beta radiation from 0.15-0.2 mc/g P/sup 32/ and 0.8 mc/g I/sup 131/ solutions correspond roughly to those of 2.5 kr gamma radiation. As to chromosome aberrations and chlorophyll mutations, the effects of 2.5 kr gamma radiation coincide roughly with those of 0.1 mc/g P/sup 32/ and 0.6-0.8 mc/g I/sup 131/ solution. If it is assumed that the effects of beta radiation are confined only to the embryo, then a 0.2 mc/g P/sup 32/ solution equals about 2.4 krad. This will account for the present data. (auth)« less

Gamma greenhouse: A chronic facility for crops improvement and agrobiotechnology

NASA Astrophysics Data System (ADS)

Azhar, M.; Ahsanulkhaliqin, A. W.

2014-02-01

Gamma irradiation is one of the most common procedures in plant mutagenesis and agrobiotechnology activities. The procedures consist of chronic and acute gamma radiation. Generally, 60Co and 137Cs are gamma radiation sources for radiation processing with relatively high energy (half-life 5.27 years for 60Co and 30.1 years for 137Cs). The energy associated with gamma radiation is high enough to break the molecular bonds and ionize atoms without affecting structure of the atomic nucleus (avoiding induction of radioactivity). The Gamma Green House (GGH) is the only chronic irradiation facility in Malaysia, located at Malaysian Nuclear Agency (Nuclear Malaysia). GGH is used for induction of mutation in plants and other biological samples at low dose radiation over period of time depending on the nature and sensitivity of the plant species. The GGH consist of circular green house with 30 meters radius, control room and irradiator with interlock system. The irradiator produces low dose gamma radiation derived from Caesium-137 radioactive source. The biological samples can be exposed to low dose radiation in days, weeks, months or years. The current irradiation rate for GGH is 2.67 Gy/hr at 1 meter from the source. Chronic gamma irradiation produces a wider mutation spectrum and useful for minimizing radiation damages towards obtaining new improved traits for research and commercial values. The prospect of the gamma greenhouse is its uses in research, educations and services on induced mutation techniques for the improvement of plant varieties and microbes. In generating awareness and attract users to the facility, Nuclear Malaysia provides wide range of irradiation services for plant species and mutagenesis consultancies to academicians, students scientists, and plant breeders, from local universities, other research institutes, and growers. Charges for irradiation and consultancy services are at nominal rates. The utilization activities of the gamma greenhouse mainly cover Research and Development, Research Collaboration, Exchange of Information, Irradiation Services, Training Programs, Education, Exchange of Scientists and Seminars/ Conferences.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ledney, G.D.; Madonna, G.S.; Elliott, T.B.

When host antimicrobial defenses are severely compromised by radiation or trauma in conjunction with radiation, death from sepsis results. To evaluate therapies for sepsis in radiation casualties, the authors developed models of acquired and induced bacterial infections in irradiated and irradiated-wounded mice. Animals were exposed to either a mixed radiation field of equal proportions of neutrons and gamma rays (n/gamma = 1) from a TRIGA reactor or pure gamma rays from 60 (Co sources). Skin wounds (15% of total body surface area) were inflicted under methoxyflurane anesthesia 1 h after irradiation. In all mice, wounding after irradiation decreased resistance tomore » infection. Treatments with the immunomodulator synthetic trehalose dicorynomycolate (S-TDCM) before or after mixed neutron-gamma irradiation or gamma irradiation increased survival. Therapy with S-TDCM for mice irradiated with either a mixed field or gamma rays increased resistance to Klebsiella pneumoniae-induced infections.« less

AN ORIENTATIONAL RESPONSE TO WEAK GAMMA RADIATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, F.A. Jr.

1963-10-01

The common planarian worm, Duesia dorotocephsla, displays a significant orientational response to increase in Cs/sup 137/ gamma radiation when the increase is no greater than six times background. The worms are able to distinguish the direction of the weak gamma source, turning away from it, whether it is presented on the right or left side. The response sign is, therefore, the same as that of the response of these negatively phototactic worms to visible light. There is a clear compass-directional relationship of the responsiveness to the experimental gamma radiation. A conspicuous negative response is present when the worms are travelingmore » northward or southward in the earth's field with the gamma change in an east-west axis. No statistically significant mean turning response to the gamma radiation is found when the worms are traveling eastward or westward in the earth's field with the gamma change in a north-south axis. The previously observed annual fluctuation in the character of the monthly orientational rhythm of north-directed worms has been confirmed in an additional year of study. During colder months, the rhythm is monthly; during warmer months it is semi-monthly. There is a semi-monthly fluctuation in the response of Dugesia to weak gamma radiation during mid-morning hours, the worms turning away from the source for four days prior to new end full moon, and toward it for two days following new and full moon. The stronger the field strength, up to 9 times backgound, the larger the amplitude of the rhythm. There is a direct relationship between intensities of gamma radiation between that of background and nine times backgound, and the strength of the negative response of the worms. Evidence suggests that the negative response of Dugesia to a gamma source may be modified by experimental alteration of the natural ambient electrostatic field. Some possible biological significances of this remarkable responsiveness to gamma radiation, and its particular properties, are discussed briefly. (auth)« less

Neutron and gamma radiation shielding material, structure, and process of making structure

DOEpatents

Hondorp, Hugh L.

1984-01-01

The present invention is directed to a novel neutron and gamma radiation elding material consisting of 95 to 97 percent by weight SiO.sub.2 and 5 to 3 percent by weight sodium silicate. In addition, the method of using this composition to provide a continuous neutron and gamma radiation shielding structure is disclosed.

POCKET $beta$ AND $gamma$ RADIOMETER (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Markelov, V.V.; Lushikhin, A.M.; Nikoforov, V.I.

A pocket BETA and gamma rate meter was designed by the Academy of Medical Sciences of U.S.S.R. for detecting gamma radiation of 0.25 to 2 Mev and for BETA particles of 0 to 50 and 0 to 500 particles/cm/sup 2/sec, with energies of 0.5 to 2 Mev. Measurements of BETA particles are made through the hack wall opening in the appuratus. The opening is closed durtng the recording of gamma radiation, which permits differentiation between the BETA and gamma radiation. The accuracy of the counter is within plus or minus 15%. (R.V.J.)

Detection system for high-resolution gamma radiation spectroscopy with neutron time-of-flight filtering

DOEpatents

Dioszegi, Istvan; Salwen, Cynthia; Vanier, Peter

2014-12-30

A .gamma.-radiation detection system that includes at least one semiconductor detector such as HPGe-Detector, a position-sensitive .alpha.-Detector, a TOF Controller, and a Digitizer/Integrator. The Digitizer/Integrator starts to process the energy signals of a .gamma.-radiation sent from the HPGe-Detector instantly when the HPGe-Detector detects the .gamma.-radiation. Subsequently, it is determined whether a coincidence exists between the .alpha.-particles and .gamma.-radiation signal, based on a determination of the time-of-flight of neutrons obtained from the .alpha.-Detector and the HPGe-Detector. If it is determined that the time-of-flight falls within a predetermined coincidence window, the Digitizer/Integrator is allowed to continue and complete the energy signal processing. If, however, there is no coincidence, the Digitizer/Integrator is instructed to be clear and reset its operation instantly.

Radioactivity Risk Assessment of Radon and Gamma Dose at One Uranium Tailings Pond in China

NASA Astrophysics Data System (ADS)

Lou, Yalong; Liu, Yong; Peng, Guowen; Zhao, Guodong; Zhang, Yan; Yang, Zhu

2018-01-01

A year-long monitoring of gamma radiation effective dose rate and radon concentration had been done in the reservoir area of one uranium tailings pond in Hunan province (The monitoring area included indoor and outdoor area of residential buildings and workshops, tailings dam slope). Afterwards, the annual effective radiation dose of the people in that radiation environment had been calculated based on the results of monitoring, as well as a radiation risk assessment. According to the assessment, gamma radiation effective dose rate and radon concentration in the monitoring area were low, and the annual effective radiation dose was far below the international standard (30mSv), which showed that the radiation would not put the people’s health at risk. However, the annual effective radiation dose of gamma was far above that of radon in the area of uranium tailings pond; therefore, it’s advisable to take quarantine measures in in the area of uranium tailings pond to keep the surrounding residents away from unnecessary ionizing radiation.

Radiosensitivity and Induction of Apoptosis by High LET Carbon Ion Beam and Low LET Gamma Radiation: A Comparative Study

PubMed Central

Ghorai, Atanu; Bhattacharyya, Nitai P.; Sarma, Asitikantha; Ghosh, Utpal

2014-01-01

Cancer treatment with high LET heavy ion beam, especially, carbon ion beam (12C), is becoming very popular over conventional radiotherapy like low LET gamma or X-ray. Combination of Poly(ADP-ribose) polymerase (PARP) inhibitor with xenotoxic drugs or conventional radiation (gamma or X-ray) is the newer approach for cancer therapy. The aim of our study was to compare the radiosensitivity and induction of apoptosis by high LET 12C and low LET gamma radiation in HeLa and PARP-1 knocked down cells. We did comet assay to detect DNA breaks, clonogenic survival assay, and cell cycle analysis to measure recovery after DNA damage. We measured apoptotic parameters like nuclear fragmentation and caspase-3 activation. DNA damage, cell killing, and induction of apoptosis were significantly higher for 12C than gamma radiation in HeLa. Cell killing and apoptosis were further elevated upon knocking down of PARP-1. Both 12C and gamma induced G2/M arrest although the 12C had greater effect. Unlike the gamma, 12C irradiation affects DNA replication as detected by S-phase delay in cell cycle analysis. So, we conclude that high LET 12C has greater potential over low LET gamma radiation in killing cells and radiosensitization upon PARP-1 inhibition was several folds greater for 12C than gamma. PMID:25018892

Evaluation of SPE and GCR Radiation Effects in Inflatable, Space Suit and Composite Habitat Materials Project

NASA Technical Reports Server (NTRS)

Waller, Jess M.; Nichols, Charles

2016-01-01

The radiation resistance of polymeric and composite materials to space radiation is currently based on irradiating materials with Co-60 gamma-radiation to the equivalent total ionizing dose (TID) expected during mission. This is an approximation since gamma-radiation is not truly representative of the particle species; namely, Solar Particle Event (SPE) protons and Galactic Cosmic Ray (GCR) nucleons, encountered in space. In general, the SPE and GCR particle energies are much higher than Co-60 gamma-ray photons, and since the particles have mass, there is a displacement effect due to nuclear collisions between the particle species and the target material. This effort specifically bridges the gap between estimated service lifetimes based on decades old Co-60 gamma-radiation data, and newer assessments of what the service lifetimes actually are based on irradiation with particle species that are more representative of the space radiation environment.

Synergistic effect of mixed neutron and gamma irradiation in bipolar operational amplifier OP07

NASA Astrophysics Data System (ADS)

Yan, Liu; Wei, Chen; Shanchao, Yang; Xiaoming, Jin; Chaohui, He

2016-09-01

This paper presents the synergistic effects in bipolar operational amplifier OP07. The radiation effects are studied by neutron beam, gamma ray, and mixed neutron/gamma ray environments. The characterateristics of the synergistic effects are studied through comparison of different experiment results. The results show that the bipolar operational amplifier OP07 exhibited significant synergistic effects in the mixed neutron and gamma irradiation. The bipolar transistor is identified as the most radiation sensitive unit of the operational amplifier. In this paper, a series of simulations are performed on bipolar transistors in different radiation environments. In the theoretical simulation, the geometric model and calculations based on the Medici toolkit are built to study the radiation effects in bipolar components. The effect of mixed neutron and gamma irradiation is simulated based on the understanding of the underlying mechanisms of radiation effects in bipolar transistors. The simulated results agree well with the experimental data. The results of the experiments and simulation indicate that the radiation effects in the bipolar devices subjected to mixed neutron and gamma environments is not a simple combination of total ionizing dose (TID) effects and displacement damage. The data suggests that the TID effect could enhance the displacement damage. The synergistic effect should not be neglected in complex radiation environments.

Inhibition of gamma-radiation induced DNA damage in plasmid pBR322 by TMG, a water-soluble derivative of vitamin E.

PubMed

Rajagopalan, Rema; Wani, Khalida; Huilgol, Nagaraj G; Kagiya, Tsutomu V; Nair, Cherupally K Krishnan

2002-06-01

Alpha-tocopherol monoglucoside (TMG), a water-soluble derivative of alpha-tocopherol, has been examined for its ability to protect DNA against radiation-induced strand breaks. Gamma radiation, up to a dose of 6 Gy (dose rate, 0.7 Gy/minute), induced a dose-dependent increase in single strand breaks (SSBs) in plasmid pBR322 DNA. TMG inhibited the formation of gamma-radiation induced DNA single strand breaks (SSBs) in a concentration-dependent manner; 500 microM of TMG protected the single strand breaks completely. It also protected thymine glycol formation induced by gamma-radiation in a dose-dependent manner, based on an estimation of thymine glycol by HPLC.

THE DEVELOPMENT OF A PHOTOTROPIC ANODIZED ALUMINUM FINISH RESPONSIVE TO GAMMA RADIATION.

DTIC Science & Technology

The present investigation was conducted to establish a phototropic anodized aluminum finish sensitive to gamma radiation. A comprehensive literature...search revealed a number of candidate phototropic materials but very little information about gamma radiation response. Because early trials...indicated that each candidate phototropic system possessed different dyeing characteristics for an anodic film, time-consuming trials with dyed anodic films

Exposure Dose Reconstruction from EPR Spectra of Tooth Enamel Exposed to the Combined Effect of X-rays and Gamma Radiation

NASA Astrophysics Data System (ADS)

Kirillov, V. A.; Kuchuro, J. I.

2014-09-01

We have used EPR dosimetry on tooth enamel to show that the combined effect of x-rays with effective energy 34 keV and gamma radiation with average energy 1250 keV leads to a significant increase in the reconstructed absorbed dose compared with the applied dose from a gamma source or from an x-ray source or from both sources of electromagnetic radiation. In simulation experiments, we develop an approach to estimating the contribution of diagnostic x-rays to the exposure dose formed in the tooth enamel by the combined effect of x-rays and gamma radiation.

Effects of High Dietary HEME Iron and Radiation on Cardiovascular Function

NASA Technical Reports Server (NTRS)

Westby, Christian M.; Brown, A. K.; Platts, S. H.

2012-01-01

The radiation related health risks to astronauts is of particular concern to NASA. Data support that exposure to radiation is associated with a number of disorders including a heightened risk for cardiovascular diseases. Independent of radiation, altered nutrient status (e.g. high dietary iron) also increases ones risk for cardiovascular disease. However, it is unknown whether exposure to radiation in combination with high dietary iron further increases ones cardiovascular risk. The intent of our proposal is to generate compulsory data examining the combined effect of radiation exposure and iron overload on sensitivity to radiation injury to address HRP risks: 1) Risk Factor of Inadequate Nutrition; 2) Risk of Cardiac Rhythm Problems; and 3) Risk of Degenerative Tissue or other Health Effects from Space Radiation. Towards our goal we propose two distinct pilot studies using the following specific aims: Vascular Aim 1: To determine the short-term consequences of the independent and combined effects of exposure to gamma radiation and elevated body iron stores on measures of endothelial function and cell viability and integrity. We hypothesize that animals that have high body iron stores and are exposed to gamma radiation will show a greater reduction in endothelial dependent nitric oxid production and larger pathological changes in endothelial integrity than animals that have only 1 of those treatments (either high iron stores or exposure to gamma radiation). Vascular Aim 2: Identify and compare the effects of gamma radiation and elevated body iron stores on the genetic and epigenetic regulation of proteins associated with endothelial cell function. We hypothesize that modifications of epigenetic control and posttranslational expression of proteins associated with endothelial cell function will be differentially altered in rats with high body iron stores and exposed to gamma radiation compared to rats with only 1 type of treatment. Cardiac Aim 1: To determine the short-term consequences of the independent and combined effects of gamma radiation and elevated body iron stores on measures of cardiac structure. We hypothesize that modifications to cardiac structure and function will be greater in rats with high body iron stores and exposed to gamma radiation than in rats that have only 1 of those treatments. Cardiac Aim 2: Identify and compare the effects of gamma radiation and elevated body iron stores on the genetic and epigenetic regulation of proteins associated with cardiac structure and function. We hypothesize that modifications of epigenetic control and posttranslational expression of proteins associated with cardiac contractile function will be differentially altered in rats with high body iron stores and exposed to gamma radiation compared to rats with only 1 type of treatment.

Annihilation radiation in cosmic gamma-ray bursts

NASA Technical Reports Server (NTRS)

Aptekar, R. L.; Golenetskii, S. V.; Guryan, Y. A.; Ilyinskii, V. N.; Mazets, E. P.

1985-01-01

The pair annihilation radiation in gamma-ray bursts is seen as broad lines with extended hard wings. This radiation is suggested to escape in a collimated beam from magnetic polar regions of neutron stars.

Evaluation of genotoxicity of the acute gamma radiation on earthworm Eisenia fetida using single cell gel electrophoresis technique (Comet assay).

PubMed

Sowmithra, K; Shetty, N J; Jha, S K; Chaubey, R C

2015-12-01

Earthworms (Eisenia fetida) most suitable biological indicators of radioactive pollution. Radiation-induced lesions in DNA can be considered to be molecular markers for early effects of ionizing radiation. Gamma radiation produces a wide spectrum of DNA. Some of these lesions, i.e., DNA strand breaks and alkali labile sites can be detected by the single-cell gel electrophoresis (SCGE) or comet assay by measuring the migration of DNA from immobilized nuclear DNA. E. fetida were exposed to different doses of gamma radiation, i.e., 1, 5, 10, 20, 30, 40 and 50Gy, and comet assay was performed for all the doses along with control at 1, 3 and 5h post irradiation to evaluate the genotoxicity of gamma radiation in this organism. The DNA damage was measured as percentage of comet tail DNA. A significant increase in DNA damage was observed in samples exposed to 5Gy and above, and the increase in DNA damage was dose dependent i.e., DNA damage was increased with increased doses of radiation. The highest DNA damage was noticed at 1h post irradiation and gradually decreased with time, i.e., at 3 and 5h post irradiation. The present study reveals that gamma radiation induces DNA damage in E. fetida and the comet assay is a sensitive and rapid method for its detection to detect genotoxicity of gamma radiation. Copyright © 2015 Elsevier B.V. All rights reserved.

Unraveling Fungal Radiation Resistance Regulatory Networks through the Genome-Wide Transcriptome and Genetic Analyses of Cryptococcus neoformans.

PubMed

Jung, Kwang-Woo; Yang, Dong-Hoon; Kim, Min-Kyu; Seo, Ho Seong; Lim, Sangyong; Bahn, Yong-Sun

2016-11-29

The basidiomycetous fungus Cryptococcus neoformans has been known to be highly radiation resistant and has been found in fatal radioactive environments such as the damaged nuclear reactor at Chernobyl. To elucidate the mechanisms underlying the radiation resistance phenotype of C. neoformans, we identified genes affected by gamma radiation through genome-wide transcriptome analysis and characterized their functions. We found that genes involved in DNA damage repair systems were upregulated in response to gamma radiation. Particularly, deletion of recombinase RAD51 and two DNA-dependent ATPase genes, RAD54 and RDH54, increased cellular susceptibility to both gamma radiation and DNA-damaging agents. A variety of oxidative stress response genes were also upregulated. Among them, sulfiredoxin contributed to gamma radiation resistance in a peroxiredoxin/thioredoxin-independent manner. Furthermore, we found that genes involved in molecular chaperone expression, ubiquitination systems, and autophagy were induced, whereas genes involved in the biosynthesis of proteins and fatty acids/sterols were downregulated. Most importantly, we discovered a number of novel C. neoformans genes, the expression of which was modulated by gamma radiation exposure, and their deletion rendered cells susceptible to gamma radiation exposure, as well as DNA damage insults. Among these genes, we found that a unique transcription factor containing the basic leucine zipper domain, named Bdr1, served as a regulator of the gamma radiation resistance of C. neoformans by controlling expression of DNA repair genes, and its expression was regulated by the evolutionarily conserved DNA damage response protein kinase Rad53. Taken together, the current transcriptome and functional analyses contribute to the understanding of the unique molecular mechanism of the radiation-resistant fungus C. neoformans IMPORTANCE: Although there are no natural environments under intense radiation, some living organisms have been found to show high radiation resistance. Organisms harboring the ability of radiation resistance have unique regulatory networks to overcome this stress. Cryptococcus neoformans is one of the radiation-resistant fungi and is found in highly radioactive environments. However, it remains elusive how radiation-resistant eukaryotic microorganisms work differentially from radiation-sensitive ones. Here, we performed transcriptome analysis of C. neoformans to explore gene expression profiles after gamma radiation exposure and functionally characterized some of identified radiation resistance genes. Notably, we identified a novel regulator of radiation resistance, named Bdr1 (a bZIP TF for DNA damage response 1), which is a transcription factor (TF) that is not closely homologous to any known TF and is transcriptionally controlled by the Rad53 kinase. Therefore, our work could shed light on understanding not only the radiation response but also the radiation resistance mechanism of C. neoformans. Copyright © 2016 Jung et al.

Radiation attenuation on labyrinth design bunker using Iridium-192 source

NASA Astrophysics Data System (ADS)

Ismail, Mohamad Pauzi bin; Sani, Suhairy bin; Masenwat, Noor Azreen bin; Mohd, Shukri; Sayuti, Shaharudin; Ahmad, Mohamad Ridzuan Bin; Mahmud, Mohamad Haniza bin; Isa, Nasharuddin bin

2017-01-01

Gamma rays are better absorbed by materials with high atomic numbers and high density. Steel, lead, depleted uranium, concrete, water or sand can be used as gamma shielding. Lead and steel are normally used for making doors of the bunker and to reduce radiation scatter. Depleted uranium is used for gamma container. Water is used in nuclear reactor as neutron and gamma absorber. Sand is used for mobile hot cell. However concrete is the most common and cheap material for gamma radiation bunker. In this research, concrete made from hematite aggregates was used to make chevron blocks for a temporary construction of labyrinth bunker. This paper explains and discusses the gamma attenuation around labyrinth bunker with concrete containing hematite aggregates.

Development of a novel gamma probe for detecting radiation direction

NASA Astrophysics Data System (ADS)

Pani, R.; Pellegrini, R.; Cinti, M. N.; Longo, M.; Donnarumma, R.; D'Alessio, A.; Borrazzo, C.; Pergola, A.; Ridolfi, S.; De Vincentis, G.

2016-01-01

Spatial localization of radioactive sources is currently a main issue interesting different fields, including nuclear industry, homeland security as well as medical imaging. It is currently achieved using different systems, but the development of technologies for detecting and characterizing radiation is becoming important especially in medical imaging. In this latter field, radiation detection probes have long been used to guide surgery, thanks to their ability to localize and quantify radiopharmaceutical uptake even deep in tissue. Radiolabelled colloid is injected into, or near to, the tumor and the surgeon uses a hand-held radiation detector, the gamma probe, to identify lymph nodes with radiopharmaceutical uptkake. The present work refers to a novel scintigraphic goniometric probe to identify gamma radiation and its direction. The probe incorporates several scintillation crystals joined together in a particular configuration to provide data related to the position of a gamma source. The main technical characteristics of the gamma locator prototype, i.e. sensitivity, spatial resolution and detection efficiency, are investigated. Moreover, the development of a specific procedure applied to the images permits to retrieve the source position with high precision with respect to the currently used gamma probes. The presented device shows a high sensitivity and efficiency to identify gamma radiation taking a short time (from 30 to 60 s). Even though it was designed for applications in radio-guided surgery, it could be used for other purposes, as for example homeland security.

Interaction of Radiation with Graphene Based Nanomaterials for Sensing Fissile Materials

DTIC Science & Technology

2016-03-01

about how ionizing radiation (gamma rays, neutrons ) and associated charged particles interact with nano-materials/structures based on graphene, which...various experimental tests of effect of light, X-rays, gamma-rays and neutrons on graphene & graphene FET) 2. What other organizations have been...knowledge about how ionizing radiation (gamma rays, neutrons ) and associated charged particles interact with nano- materials/structures based on graphene

[Chlorophyll mutations induced by gamma radiation in Phaseolus vulgaris L].

PubMed

Meoño, M E

1975-07-01

In a study of chlorophyll mutants of Phaseolus vulgaris L. through Co60 gamma radiation, five types of mutants, classified as albino, cream, yellow, yellow-green and light green were obtained; all were lethal; their segregation was always proportionally lower than the Mendelian. Gamma radiation-induced mutations in black beans do not depart significantly from those obtained elsewhere in barley and wheat.

[Changes in immunobiological reactivity under the combined action of microwave, infrasonic and gamma irradiation].

PubMed

Grigor'ev, Iu G; Batanov, G V; Stepanov, V S

1983-01-01

In experiments on rats and rabbits a study was made of the combined effect of 9.3 gHz and 0.1 gHz (200 and 1530 muW/cm2, respectively), infrasound (8 Hz, 115 db), and gamma-radiation (cumulative dose of 5.5 Gy) on cell and humoral immunity, and on autoimmune processes. It was shown that preirradiation with microwaves increased the resistance of the organism to gamma-radiation, and microwaves combined with infrasound enhanced the biological effect of gamma-radiation.

Process and apparatus for detecting presence of plant substances

DOEpatents

Kirby, John A.

1991-01-01

An apparatus and process for detecting the presence of plant substances in a particular environment which comprises the steps of: measuring the background K40 gamma ray radiation level in a particular environment with a 1.46 MeV gamma ray counter system; measuring the amount of K40 gamma ray radiation emanating from a package containing a plant substance being passed through an environment with a counter; and generating an alarm signal when the total K40 gamma ray radiation reaches a predetermined level over and above the background level.

Inactivation of avirulent Yersinia pestis in Butterfield's phosphate buffer and frankfurters by UVC (254 nm) and gamma radiation.

PubMed

Sommers, Christopher H; Cooke, Peter H

2009-04-01

Yersinia pestis is the causative agent of plague. Although rare, pharyngeal plague in humans has been associated with consumption or handling of meat prepared from infected animals. The risks of contracting plague from consumption of deliberately contaminated food are currently unknown. Gamma radiation is a penetrating form of electromagnetic radiation, and UVC radiation is used for decontamination of liquids or food surfaces. Gamma radiation D10-values (the radiation dose needed to inactivate 1 log unit pathogen) were 0.23 (+/-0.01) and 0.31 (+/-0.03) kGy for avirulent Y. pestis inoculated into Butterfield's phosphate buffer and onto frankfurter surfaces, respectively, at 0 degree C. A UVC radiation dose of 0.25 J/cm2 inactivated avirulent Y. pestis suspended in Butterfield's phosphate buffer. UVC radiation doses of 0.5 to 4.0 J/cm2 inactivated 0.97 to 1.20 log units of the Y. pestis surface inoculated onto frankfurters. A low gamma radiation dose of 1.6 kGy could provide a 5-log reduction and a UVC radiation dose of 1 to 4 J/cm2 would provide a 1-log reduction of Y. pestis surface inoculated onto frankfurters. Y. pestis was capable of growth on frankfurters during refrigerated storage (10 degrees C). Gamma radiation of frankfurters inhibited the growth of Y. pestis during refrigerated storage, and UVC radiation delayed the growth of Y. pestis.

Gamma and neutrino radiation dose from gamma ray bursts and nearby supernovae.

PubMed

Karam, P Andrew

2002-04-01

Supernovae and gamma ray bursts are exceptionally powerful cosmic events that occur randomly in space and time in our galaxy. Their potential to produce very high radiation levels has been discussed, along with speculation that they may have caused mass extinctions noted from the fossil record. It is far more likely that they have produced radiation levels that, while not lethal, are genetically significant, and these events may have influenced the course of evolution and the manner in which organisms respond to radiation insult. Finally, intense gamma radiation exposure from these events may influence the ability of living organisms to travel through space. Calculations presented in this paper suggest that supernovae and gamma ray bursts are likely to produce sea-level radiation exposures of about I Gy with a mean interval of about five million years and sea-level radiation exposures of about 0.2 Gy every million years. Comets and meteors traveling through space would receive doses in excess of 10 Gy at a depth of 0.02 m at mean intervals of 4 and 156 million years, respectively. This may place some constraints on the ability of life to travel through space either between planets or between planetary systems. Calculations of radiation dose from neutrino radiation are presented and indicate that this is not a significant source of radiation exposure for even extremely close events for the expected neutrino spectrum from these events.

Attenuation of Neutron and Gamma Radiation by a Composite Material Based on Modified Titanium Hydride with a Varied Boron Content

NASA Astrophysics Data System (ADS)

Yastrebinskii, R. N.

2018-04-01

The investigations on estimating the attenuation of capture gamma radiation by a composite neutron-shielding material based on modified titanium hydride and Portland cement with a varied amount of boron carbide are performed. The results of calculations demonstrate that an introduction of boron into this material enables significantly decreasing the thermal neutron flux density and hence the levels of capture gamma radiation. In particular, after introducing 1- 5 wt.% boron carbide into the material, the thermal neutron flux density on a 10 cm-thick layer is reduced by 11 to 176 factors, and the capture gamma dose rate - from 4 to 9 times, respectively. The difference in the degree of reduction in these functionals is attributed to the presence of capture gamma radiation in the epithermal region of the neutron spectrum.

Induction and quantification of gammma-H2AX foci following cx- and gamma-irradiaton

NASA Technical Reports Server (NTRS)

Leatherbarrow, E. L.; Cucinotta, F. A.; O'Neill, Peter

2004-01-01

Following DNA damage the histone H2AX becomes phosphorylated and can be visualised by immunofluorescence as an indicator of DSBs in individual cells. Using a wild type hamster cell line (V79-4) exposed to either a-particles or to Co-60 gamma-rays to induce DNA DSBs at different doses (20-200OmGy), the dose dependent induction of gamma-H2AX foci were scored both manually (by eye) and using image analysis. A linearly dependence on dose was found for both radiations. The number of DSBs determined by image analysis after a post-irradiation period of 30 minutes at 37 C, is 16.6 foci/cell/Gy for alpha-irradiation and 12.2 foci/cell/Gy for gamma-irradiation; the latter being 3-4 times the levels observed by eye and comparable to gamma-radiation-induced levels of prompt DSBs more recently reported using pulse field gel electrophoresis (approx. 16 DSBs/Gy). The average size of the gamma-H2AX foci induced by alpha-irradiation (0.30 square micrometers) is approximately 1.5 times larger than those induced by gamma-irradiation (0.19 square micrometers). The timescale of induction and removal of DSBs up to 24 hours post-irradiation, was investigated with gamma-H2AX foci levels found to remain significantly higher than controls for 4 or 6 hours in gamma-irradiated samples or alpha irradiated samples, respectively. These results demonstrate that not only gamma radiation but also alpha-radiation induce phosphorylation of the H2AX histone in response to DSBs even at low doses (20mGy for gamma-rays, 1 track/cell on average for alpha-particles) and the variation in size and dephosphorylation of the induced foci is dependent on radiation quality (LET).

The effects of gamma radiation, UV and visible light on ATP levels in yeast cells depend on cellular melanization.

PubMed

Bryan, Ruth; Jiang, Zewei; Friedman, Matthew; Dadachova, Ekaterina

2011-10-01

Previously we have shown that growth of melanized fungi is stimulated by low levels of gamma radiation. The goal of this study was to examine the effects of visible light, UV light, and gamma radiation on the energy level (ATP concentration) in melanized Cryptococcus neoformans cells. Melanized C. neoformans cells as well as non-melanized controls were subjected to visible, UV or gamma radiation, and ATP was quantified by measuring the amount of light emitted by the ATP-dependent reaction of luciferase with luciferin. We found that all three forms of radiation led to a reduction in the ATP levels in melanized C. neoformans cells. This points to a universal melanin-related mechanism underlying observation of ATP decrease in irradiated melanized cells. In contrast, in non-melanized cells visible light led to increase in ATP levels; gamma radiation did not cause any changes while UV exposure resulted in some ATP decrease, however, much less pronounced than in melanized cells. Copyright © 2011 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

[Separation of the effects of transmutation and radiation after incorporation of radionuclides into DNA (author's transl)].

PubMed

Hamann, H J; Irskens, M

1975-01-01

Among the various methods for studying the relative effects of transmutation and radiation of incorporated nuclides, simulation of beta radiation by external gamma exposure is of practical importance. Self-irradiation and mutual irradiation of the labeled cells cannot be neglected in any case. Furthermore, additional hypothetical and experimental problems may arise from using either external beta radiation or different isotopes of an element. By means of external gamma irradiation on the other hand, this being equivalent to the internal beta radiation from a microdosimetrical point of view, the radiation effect of the nuclide alone can be observed without any modification of other experimental parameters. To determine such equivalent gamma radiation for labeled cell nuclei of Vicia faba roots, the authors applied the Monte Carlo Method to the beta spectra of 32-P, 3-H, 14-C and 131-J, to the energy-dependent LET and to different cell diameters. The existence of secondary particle equilibrium inside the nuclei during gamma exposure was assumed. For certain radionuclides and cell sizes it is possible to calculate gamma spectra which induce energy spectra in the nuclei similar to those caused by the beta particles originating in the nuclear DNA.

Viability of Acremonium coenophialum in tall fescue seed after ionizing radiation treatments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bagegni, A.M.; Sleper, D.A.; Kerr, H.D.

Planting tall fescue (Festuca arundinacea Schreb.) seed free of the endophyte Acremonium coenophialum Morgan-Jones and Gams allows establishment of swards free of the fungus. Eradication of the fungal endophyte from infected tall fescue seeds containing 130 g kg{sup {minus}1} moisture using ionizing radiation was investigated. Three sources of radiation were used: gamma rays ({sup 60}Co source), neutron particles ({sup 252}Cf source), and a thermal neutron beam. The percent germination of tall fescue seeds among gamma doses did not differ significantly (P < 0.05) from the control treatment and did not show a significant negative response (R{sub 2} = 0.41) tomore » increasing levels of gamma radiation. At 250 Gy of gamma radiation, percent germination after 14 d was still > 90%. Percent seed germination of tall fescue and high levels of radiation were negatively correlated for both sources of neutrons. Gamma radiation was shown to reduce (P < 0.01) the percent of the viable endophyte to {approx} 10% of control. The {sup 252}Cf and thermal neutrons reduced the percent of tall fescue infected by the endophyte to {approx} 30% without deleterious effects on seed germination.« less

Plutonium radiation surrogate

DOEpatents

Frank, Michael I [Dublin, CA

2010-02-02

A self-contained source of gamma-ray and neutron radiation suitable for use as a radiation surrogate for weapons-grade plutonium is described. The source generates a radiation spectrum similar to that of weapons-grade plutonium at 5% energy resolution between 59 and 2614 keV, but contains no special nuclear material and emits little .alpha.-particle radiation. The weapons-grade plutonium radiation surrogate also emits neutrons having fluxes commensurate with the gamma-radiation intensities employed.

Influence of gamma-radiation on the nutritional and functional qualities of lotus seed flour.

PubMed

Bhat, Rajeev; Sridhar, Kandikere Ramaiah; Karim, Alias A; Young, Chiu C; Arun, Ananthapadmanabha B

2009-10-28

In the present study, we investigated the physicochemical and functional properties of lotus seed flour exposed to low and high doses of gamma-radiation (0-30 kGy; the dose recommended for quarantine and hygienic purposes). The results indicated raw seed flour to be rich in nutrients with minimal quantities of antinutritional factors. Irradiation resulted in a dose-dependent increase in some of the proximal constituents. The raw and gamma-irradiated seeds meet the Food and Agricultural Organization-World Health Organization recommended pattern of essential amino acids. Some of the antinutritional factors (phytic acid, total phenolics, and tannins) were lowered with gamma-irradiation, while the seed flours were devoid of lectins, L-3,4-dihydroxyphenylalanine, and polonium-210. The functional properties of the seed flour were significantly improved with gamma-radiation. gamma-radiation selectively preserved or improved the desired nutritional and functional traits of lotus seeds, thus ensuring a safe production of appropriate nutraceutically valued products.

Purification of sulfide-alkali effluent with the aid of ionizing radiation. [Gamma radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petryaev, E.P.; Gerasimovich, O.A.; Kovalevskaya, A.M.

1984-03-01

The treatment of sulfide-alkali effluent under the effect of ionizing radiation was investigated. The source was an LMB-..gamma..-1M ..gamma..-apparatus with /sup 137/Cs source. The dose rate was 52 rad/s. Irradiation was done in glass ampules and in vessels allowing bubbling with air and irradiation to be carried out at the same time. 7 references, 1 figure, 1 table.

Effects of gamma radiation on the early developmental stages of Zebrafish (Danio rerio).

PubMed

Praveen Kumar, M K; Shyama, S K; Kashif, Shamim; Dubey, S K; Avelyno, D'costa; Sonaye, B H; Kadam Samit, B; Chaubey, R C

2017-08-01

The zebrafish is gaining importance as a popular vertebrate model organism and is widely employed in ecotoxicological studies, especially for the biomonitoring of pollution in water bodies. There is limited data on the genetic mechanisms governing the adverse health effects in regards to an early developmental exposure to gamma radiation. In the present study zebrafish (Danio rerio) embryos were exposed to 1, 2.5, 5, 7.5 and 10Gy of gamma radiation at 3h post fertilization (hpf). Different developmental toxicity endpoints were investigated. Further, expression of genes associated with the development and DNA damage i.e. (sox2 sox19a and p53) were evaluated using Quantitative PCR (qPCR). The significant changes in the expression of sox2 sox19a and p53 genes were observed. This data was supported the developmental defects observed in the zebrafish embryo exposed to gamma radiation such as i.e. increased DNA damage, decreased hatching rate, increase in median hatching time, decreased body length, increased mortality rate, increased morphological deformities. Further, study shows that the potential ecotoxicological threat of gamma radiation on the early developmental stages of zebrafish. Further, it revealed that the above parameters can be used as predictive biomarkers of gamma radiation exposure. Copyright © 2017. Published by Elsevier Inc.

Effect of gamma irradiation on the microbial load, nutrient composition and free radical scavenging activity of Nelumbo nucifera rhizome

NASA Astrophysics Data System (ADS)

Khattak, Khanzadi Fatima; Simpson, Thomas James; Ihasnullah

2009-03-01

The assurance of microbial quality is necessary to make plant materials suitable for human consumption and commercialization. The aim of the present study was to evaluate the possibility to apply the gamma radiation treatment on the rhizome samples of Nelumbo nucifera for microbial decontamination. The radiation processing was carried out at dose levels of 1, 2, 4 and 6 kGy. The irradiated and control samples were analyzed for microbial load, organoleptic acceptance, extraction yield, proximate composition, phenolic contents and DPPH scavenging activity. The results indicated that gamma radiation treatment significantly reduced microbial load and increased the storability of the irradiated samples. The treated samples were also acceptable sensorically. The extraction yield and phenolic contents increased with the increase of radiation dose. Gamma radiation also enhanced the DPPH scavenging activity.

Energy-dependent RBE of neutrons to induce micronuclei in root-tip cells of Allium cepa onion irradiated as dry dormant seeds and seedlings.

PubMed

Zhang, Wenyi; Fujikawa, Kazuo; Endo, Satoru; Ishikawa, Masayori; Ohtaki, Megu; Ikeda, Hideo; Hoshi, Masaharu

2003-06-01

The relative biological effectiveness (RBE) of various energy neutrons produced from a Schenkel-type accelerator at the Research Institute for Radiation Biology and Medicine, Hiroshima University (HIRRAC), compared with 60Co gamma-ray radiation was determined. The neutron radiations and gamma-ray radiation produced good linear changes in the frequency of micronuclei induced in the root-tip cells of Allium cepa onion irradiated as dry dormant seeds (seed assay) and seedlings (seedling assay) with varying radiation doses. Therefore the RBE for radiation-induced micronuclei can be calculated as the ratio of the slopes of the fitted linear dose response for the neutron radiations and the 60Co gamma-ray radiation. The RBE values by seed assay and seedling assay decreased to 174 +/- 7, from 216 +/- 9, and to 31.4 +/- 1.0, from 45.3 +/- 1.3 (one standard error), respectively, when neutron energies increased to 1.0 MeV, from 0.2 MeV, in the present study. Furthermore, the ratio of the micronucleus induction rates of seed assay to seedling assay by gamma-ray radiation was much lower than that by neutron radiations.

Measurements of environmental terrestrial gamma radiation dose rate in three mountainous locations in the western region of Saudi Arabia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Ghorabie, Fayez H.H.

2005-06-01

This paper describes measurements of external gamma radiation dose rate from terrestrial gamma-rays 1 m above the ground in three different mountainous locations in the western region of the Kingdom of Saudi Arabia. These locations are At-Taif city, Al-Hada village, and Ash-Shafa village. CaSO{sub 4}:Dy (TLD-900) thermoluminescent dosimeters were used for the detection of terrestrial gamma radiation at 40 different places in the three locations. The values of terrestrial gamma radiation dose rate measured ranged between 14 and 279 nGy h{sup -1} for the time interval from June 2001 to June 2002. The measured dose rate varied with the seasonmore » of the year. The average gamma radiation dose rates were 468, 541, and 781 {mu}Gy y{sup -1} for At-Taif city, Al-Hada village, and Ash-Shafa village, respectively. The corresponding average absorbed doses to the population of the three locations were 328, 379, and 547 {mu}Sv y{sup -1}, respectively. The quality factor of 0.7 Sv Gy{sup -1} was applied in the calculations of the absorbed dose to humans.« less

Determination of the gamma-ray skyshine dose contribution in a Loss Of Shielding accident

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dennis, M.L.; Weiner, R.F.; Osborn, D.M.

2007-07-01

The goal of this research is to determine the gamma-ray dose contribution from skyshine. In a transportation accident involving the loss of lead gamma shielding, first responders to the accident will be exposed to both direct gamma radiation streaming from the exposed spent nuclear fuel and atmospherically reflected gamma radiation. The reflected radiation is referred to as skyshine and should contribute minimally to the overall dose; however, when there is minimal shielding above the exposed source, skyshine at large distances from the source must be considered. The program SKYDOSE developed by Shultis and Faw evaluates the gamma-ray skyshine dose frommore » a point, isotropic, polyenergetic, gamma-photon source. Assuming an infinite black wall shielding all direct radiation, the model assumes a first responder is located at varying distances from the wall. Skyshine doses are calculated both through SKYDOSE's integral line-beam method and an approximate approach prescribed by the National Council of Radiation Protection and Measurements. Initial results from SKYDOSE indicate nearly equivalent dose rates from either direct or skyshine radiation at nine meters from the wall, which seemed unusual and not readily explained. NCRP methodology, however, yields skyshine dose rates which are drastically smaller than direct dose rates at the same distance. Further investigation using the program MicroSkyshine{sup R}, which allows a variety of source configurations, suggests skyshine contributes minimally to dose in a loss-of-shielding accident. (authors)« less

High energy gamma ray results from the second small astronomy satellite

NASA Technical Reports Server (NTRS)

Fichtel, C. E.; Hartman, R. C.; Kniffen, D. A.; Thompson, D. J.; Bignami, G. F.; Oegelman, H.; Oezel, M. F.; Tuemer, T.

1974-01-01

A high energy (35 MeV) gamma ray telescope employing a thirty-two level magnetic core spark chamber system was flown on SAS 2. The high energy galactic gamma radiation is observed to dominate over the general diffuse radiation along the entire galactic plane, and when examined in detail, the longitudinal and latitudinal distribution seem generally correlated with galactic structural features, particularly with arm segments. The general high energy gamma radiation from the galactic plane, explained on the basis of its angular distribution and magnitude, probably results primarily from cosmic ray interactions with interstellar matter.

Gamma irradiation to improve plant vigour, grain development, and yield attributes of wheat

NASA Astrophysics Data System (ADS)

Singh, Bhupinder; Datta, P. S.

2010-02-01

Utilizing low dose gamma radiation holds promise for physiological crop improvement. Seed treatment of low dose gamma radiation 0.01-0.10 kGy reduced plant height, improved plant vigour, flag leaf area, total and number of EBT. Gamma irradiation increased grain yield due to an increase in number of EBT and grain number while 1000 grain weight was negatively affected. Further uniformity in low dose radiation response in wheat in the field suggests that the affect is essentially at physiological than at genetic level and that role of growth hormones could be crucial.

THE RESISTANCE TO $gamma$ RADIATION OF THE WORKER BEE (in French)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Courtois, G.; Lecomte, J.

The worker bee which has been subjected to gamma radiation from a Co/ sup 60/ source can withstand without apparent physical damage a dose of 18,000 r. At 90,000 r there is, however, appreciable damage. At a dose of 200,000 r, death is immediate in 100% of the cases. The physiological state of the bee plays an important role in determining its resistance to gamma radiation. (auth)

Gamma Ray Astrophysics: New insight into the universe

NASA Technical Reports Server (NTRS)

Fichtel, C. E.; Trombka, J. I.

1981-01-01

Gamma ray observations of the solar system, the galaxy and extragalactic radiation are reported. Topics include: planets, comets, and asteroids; solar observations; interstellar medium and galactic structure; compact objects; cosmology; and diffuse radiation. The instrumentation used in gamma ray astronomy in covered along with techniques for the analysis of observational spectra.

Highlights of GeV Gamma-Ray Astronomy

NASA Technical Reports Server (NTRS)

Thompson, David J.

2010-01-01

Because high-energy gamma rays are primarily produced by high-energy particle interactions, the gamma-ray survey of the sky by the Fermi Gamma-ray Space Telescope offers a view of sites of cosmic ray production and interactions. Gamma-ray bursts, pulsars, pulsar wind nebulae, binary sources, and Active Galactic Nuclei are all phenomena that reveal particle acceleration through their gamma-ray emission. Diffuse Galactic gamma radiation, Solar System gamma-ray sources, and energetic radiation from supernova remnants are likely tracers of high-energy particle interactions with matter and photon fields. This paper will present a broad overview of the constantly changing sky seen with the Large Area Telescope (LAT) on the Fermi spacecraft.

Pulsed high-energy gamma rays from PSR 1055-52

NASA Technical Reports Server (NTRS)

Fierro, J. M.; Bertsch, D. L.; Brazier, K. T.; Chiang, J.; D'Amico, N.; Fichtel, C. E.; Hartman, R. C.; Hunter, S. D.; Johnston, S.; Kanbach, G.

1993-01-01

The Energetic Gamma Ray Experiment Telescope (EGRET) aboard the Compton Gamma Ray Observatory has detected a high-energy gamma-ray source at a position coincident with that of the radio pulsar PSR 1055-52. Analysis of the EGRET data at the radio pulsar period of 197 ms has revealed pulsed gamma-radiation at energies above 300 MeV, making PSR 1055-52 the fifth detected high-energy gamma-ray pulsar. The pulsed radiation from PSR 1055-52 has a very hard photon spectral index of -1.18 +/- 0.16 and a high efficiency for converting its rotational energy into gamma-rays. No unpulsed emission was observed.

Dibasic calcium phosphate dihydrate, USP material compatibility with gamma radiation

NASA Astrophysics Data System (ADS)

Betancourt Quiles, Maritza

Gamma radiation is a commonly used method to reduce the microbial bioburden in compatible materials when it is applied at appropriate dose levels. Gamma irradiation kills bacteria and mold by breaking down the organism’s DNA and inhibiting cell division. The purpose of this study is to determine the radiation dosage to be used to treat Dibasic Calcium Phosphate Dihydrate, USP (DCPD) and to evaluate its physicochemical effects if any, on this material. This material will be submitted to various doses of gamma radiation that were selected based on literature review and existing regulations that demonstrate that this method is effective to reduce or eliminate microbial bioburden in natural source and synthetic materials. Analytical testing was conducted to the DCPD exposed material in order to demonstrate that gamma radiation does not alter the physicochemical properties and material still acceptable for use in the manufacture of pharmaceutical products. The results obtained through this study were satisfactory and demonstrated that the gamma irradiation dosages from 5 to 30 kGy can be applied to DCPD without altering its physicochemical properties. These are supported by the Assay test data evaluation of lots tested before and after gamma irradiation implementation that show no significant statistical difference between irradiated and non irradiated assay results. The results of this study represent an achievement for the industry since they provide as an alternative the use of Gamma irradiation technology to control the microbial growth in DCPD.

Exposure to indoor background radiation and urinary concentrations of 8-hydroxydeoxyguanosine, a marker of oxidative DNA damage.

PubMed Central

Sperati, A; Abeni, D D; Tagesson, C; Forastiere, F; Miceli, M; Axelson, O

1999-01-01

We investigated whether exposure to indoor [gamma]-radiation and radon might be associated with enough free radical formation to increase urinary concentrations of 8-hydroxydeoxyguanosine (8-OHdG), a sensitive marker of DNA damage, due to a hydroxyl radical attack at the C8 of guanine. Indoor radon and [gamma]-radiation levels were measured in 32 dwellings for 6 months by solid-state nuclear track detectors and thermoluminescent dosimeters, respectively. Urine samples for 8-OHdG determinations were obtained from 63 healthy adult subjects living in the measured dwellings. An overall tendency toward increasing levels of 8-OHdG with increasing levels of radon and [gamma]-radiation was seen in the females, presumably due to their estimated longer occupancy in the dwellings measured. Different models were considered for females, with the steepest slopes obtained for [gamma]-radiation with a coefficient of 0.500 (log nmol/l of 8-OHdG for each unit increase of [gamma]-radiation on a log scale) (p<0.01), and increasing to 0.632 (p = 0.035), but with larger variance, when radon was included in the model. In conclusion, there seems to be an effect of indoor radioactivity on the urinary excretion of 8-OHdG for females, who are estimated to have a higher occupancy in the dwellings measured than for males, for whom occupational and other agents may also influence 8-OHdG excretion. ree radicals; [gamma]-radiation; radon. PMID:10064551

Mold and aflatoxin reduction by gamma radiation of packed hot peppers and their evolution during storage.

PubMed

Iqbal, Qumer; Amjad, Muhammad; Asi, Muhammad Rafique; Ariño, Agustin

2012-08-01

The effect of gamma radiation on moisture content, total mold counts, Aspergillus counts, and aflatoxins of three hot pepper hybrids (Sky Red, Maha, and Wonder King) was investigated. Whole dried peppers packed in polyethylene bags were gamma irradiated at 0 (control), 2, 4, and 6 kGy and stored at 25°C for 90 days. Gamma radiation proved to be effective in reducing total mold and Aspergillus counts in a dose-dependent relationship. Total mold counts in irradiated peppers immediately after treatments were significantly lowered compared with those in nonirradiated samples, achieving 90 and 99% reduction at 2- and 4-kGy doses, respectively. Aspergillus counts were significantly reduced, by 93 and 97%, immediately after irradiation at doses of 2 and 4 kGy, respectively. A radiation dose of 6 kGy completely eliminated the population of total molds and Aspergillus fungi. The evolution of total molds in control and irradiated samples indicated no further fungal proliferation during 3 months of storage at 25°C. Aflatoxin levels were slightly affected by radiation doses of 2 and 4 kGy and showed a nonsignificant reduction of 6% at the highest radiation dose of 6 kGy. The distinct effectiveness of gamma radiation in molds and aflatoxins can be explained by the target theory of food irradiation, which states that the likelihood of a microorganism or a molecule being inactivated by gamma rays increases as its size increases.

Development of ultrashort x-ray/gamma-ray sources using ultrahigh power lasers (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kim, Hyung Taek; Nakajima, Kazuhisa; Hojbota, Calin; Jeon, Jong Ho; Rhee, Yong-Joo; Lee, Kyung Hwan; Lee, Seong Ku; Sung, Jae Hee; Lee, Hwang Woon; Pathak, Vishwa B.; Pae, Ki Hong; Sebban, Stéphane; Tissandier, Fabien; Gautier, Julien; Ta Phuoc, Kim; Malka, Victor; Nam, Chang Hee

2017-05-01

Short-pulse x-ray/gamma-ray sources have become indispensable light sources for investigating material science, bio technology, and photo-nuclear physics. In past decades, rapid advancement of high intensity laser technology led extensive progresses in the field of radiation sources based on laser-plasma interactions - x-ray lasers, betatron radiation and Compton gamma-rays. Ever since the installation of a 100-TW laser in 2006, we have pursued the development of ultrashort x-ray/gamma-ray radiations, such as x-ray lasers, relativistic high-order harmonics, betatron radiation and all-optical Compton gamma-rays. With the construction of two PW Ti:Sapphire laser beamlines having peak powers of 1.0 PW and 1.5 PW in 2010 and 2012, respectively [1], we have investigated the generation of multi-GeV electron beams [2] and MeV betatron radiations. We plan to carry out the Compton backscattering to generate MeV gamma-rays from the interaction of a GeV electron beam and a PW laser beam. Here, we present the recent progress in the development of ultrashort x-ray/gamma-ray radiation sources based on laser plasma interactions and the plan for developing Compton gamma-ray sources driven by the PW lasers. In addition, we will present the applications of laser-plasma x-ray lasers to x-ray holography and coherent diffraction imaging. [references] 1. J. H. Sung, S. K. Lee, T. J. Yu, T. M. Jeong, and J. Lee, Opt. Lett. 35, 3021 (2010). 2. H. T. Kim, K. H. Pae, H. J. Cha, I J. Kim, T. J. Yu, J. H. Sung, S. K. Lee, T. M. Jeong, J. Lee, Phys. Rev. Lett. 111, 165002 (2013).

Protracted low-dose radiation priming and response of liver to acute gamma and proton radiation.

PubMed

Gridley, D S; Mao, X W; Cao, J D; Bayeta, E J M; Pecaut, M J

2013-10-01

This study evaluated liver from C57BL/6 mice irradiated with low-dose/low-dose-rate (LDR) γ-rays (0.01 Gy, 0.03 cGy/h), with and without subsequent exposure to acute 2 Gy gamma or proton radiation. Analyses were performed on day 56 post-exposure. Expression patterns of apoptosis-related genes were strikingly different among irradiated groups compared with 0 Gy (p < 0.05). Two genes were affected in the Gamma group, whereas 10 were modified in the LDR + Gamma group. In Proton and LDR + Proton groups, there were six and 12 affected genes, respectively. Expression of genes in the Gamma (Traf3) and Proton (Bak1, Birc2, Birc3, Mcl1) groups was no longer different from 0 Gy control group when mice were pre-exposed to LDR γ-rays. When each combined regimen was compared with the corresponding group that received acute radiation alone, two genes in the LDR + Gamma group and 17 genes in the LDR + Proton group were modified; greatest effect was on Birc2 and Nol3 (> 5-fold up-regulated by LDR + Protons). Oxygen radical production in livers from the LDR + Proton group was higher in LDR, Gamma, and LDR + Gamma groups (p < 0.05 vs. 0 Gy), but there were no differences in phagocytosis of E. coli. Sections stained with hematoxylin and eosin (H&E) suggested more inflammation, with and without necrosis, in some irradiated groups. The data demonstrate that response to acute radiation is dependent on radiation quality and regimen and that some LDR γ-ray-induced modifications in liver response were still evident nearly 2 months after exposure.

High-energy Emission from Nonrelativistic Radiative Shocks: Application to Gamma-Ray Novae

NASA Astrophysics Data System (ADS)

Vurm, Indrek; Metzger, Brian D.

2018-01-01

The observation of GeV gamma-rays from novae by Fermi/LAT demonstrates that the nonrelativistic radiative shocks in these systems can accelerate particles to energies of at least ∼10 GeV. The low-energy extension of the same nonthermal particle distribution inevitably gives rise to emission in the hard X-ray band. Above ≳ 10 {keV}, this radiation can escape the system without significant absorption/attenuation, and can potentially be detected by NuSTAR. We present theoretical models for hard X-ray and gamma-ray emission from radiative shocks in both leptonic and hadronic scenarios, accounting for the rapid evolution of the downstream properties due to the fast cooling of thermal plasma. We find that due to strong Coulomb losses, only a fraction of {10}-4{--}{10}-3 of the gamma-ray luminosity is radiated in the NuSTAR band; nevertheless, this emission could be detectable simultaneously with the LAT emission in bright gamma-ray novae with a ∼50 ks exposure. The spectral slope in hard X-rays is α ≈ 0 for typical nova parameters, thus serving as a testable prediction of the model. Our work demonstrates how combined hard X-ray and gamma-ray observations can be used to constrain properties of the nova outflow (velocity, density, and mass outflow rate) and particle acceleration at the shock. A very low X-ray to gamma-ray luminosity ratio ({L}{{X}}/{L}γ ≲ 5× {10}-4) would disfavor leptonic models for the gamma-ray emission. Our model can also be applied to other astrophysical environments with radiative shocks, including SNe IIn and colliding winds in massive star binaries.

The effect of gamma radiation on the Common carp (Cyprinus carpio): In vivo genotoxicity assessment with the micronucleus and comet assays.

PubMed

M K, Praveen Kumar; Soorambail K, Shyama; Bhagatsingh Harisingh, Sonaye; D'costa, Avelyno; Ramesh Chandra, Chaubey

2015-10-01

Radioactive wastes may be leached into freshwater, either accidentally or in industrial effluents. We have studied gamma radiation-induced DNA damage in the freshwater fish Cyprinus carpio. Fish were irradiated with 2-10Gy gamma radiation and genotoxic effects in blood cells were studied with the micronucleus (MN) and comet assays. Micronuclei and a dose-dependent increase in comet-tail DNA were seen in dose- and time-dependent studies. The highest % tail DNA was observed at 24h, declining until 72h, which may indicate the repair of radiation-induced DNA single-strand breaks after gamma radiation. However, double-stranded DNA damage may not have been repaired, as indicated by increased micronuclei at later periods. A positive correlation was observed between the comet and micronucleus assay results. This study confirms the mutagenic/genotoxic potential of gamma radiation in the Common carp, as well as the possible combined use of the micronucleus and comet assays for in vivo laboratory studies with fresh-water fish for screening the genotoxic potential of radioactive pollution. Copyright © 2015 Elsevier B.V. All rights reserved.

The biobehavioral and neuroimmune impact of low-dose ionizing radiation.

PubMed

York, Jason M; Blevins, Neil A; Meling, Daryl D; Peterlin, Molly B; Gridley, Daila S; Cengel, Keith A; Freund, Gregory G

2012-02-01

In the clinical setting, repeated exposures (10-30) to low-doses of ionizing radiation (≤200 cGy), as seen in radiotherapy for cancer, causes fatigue. Almost nothing is known, however, about the fatigue inducing effects of a single exposure to environmental low-dose ionizing radiation that might occur during high-altitude commercial air flight, a nuclear reactor accident or a solar particle event (SPE). To investigate the short-term impact of low-dose ionizing radiation on mouse biobehaviors and neuroimmunity, male CD-1 mice were whole body irradiated with 50 cGy or 200 cGy of gamma or proton radiation. Gamma radiation was found to reduce spontaneous locomotor activity by 35% and 36%, respectively, 6 h post irradiation. In contrast, the motivated behavior of social exploration was un-impacted by gamma radiation. Examination of pro-inflammatory cytokine gene transcripts in the brain demonstrated that gamma radiation increased hippocampal TNF-α expression as early as 4 h post-irradiation. This was coupled to subsequent increases in IL-1RA (8 and 12 h post irradiation) in the cortex and hippocampus and reductions in activity-regulated cytoskeleton-associated protein (Arc) (24 h post irradiation) in the cortex. Finally, restraint stress was a significant modulator of the neuroimmune response to radiation blocking the ability of 200 cGy gamma radiation from impairing locomotor activity and altering the brain-based inflammatory response to irradiation. Taken together, these findings indicate that low-dose ionizing radiation rapidly activates the neuroimmune system potentially causing early onset fatigue-like symptoms in mice. Copyright © 2011 Elsevier Inc. All rights reserved.

The biobehavioral and neuroimmune impact of low-dose ionizing radiation

PubMed Central

York, Jason M; Blevins, Neil A; Meling, Daryl D; Peterlin, Molly B; Gridley, Daila S; Cengel, Keith A; Freund, Gregory G

2011-01-01

In the clinical setting, repeated exposures (10–30) to low-doses of ionizing radiation (≤ 200 cGy), as seen in radiotherapy for cancer, causes fatigue. Almost nothing is known, however, about the fatigue inducing effects of a single exposure to environmental low-dose ionizing radiation that might occur during high-altitude commercial air flight, a nuclear reactor accident or a solar particle event (SPE). To investigate the short-term impact of low-dose ionizing radiation on mouse biobehaviors and neuroimmunity, male CD-1 mice were whole body irradiated with 50 cGy or 200 cGy of gamma or proton radiation. Gamma radiation was found to reduce spontaneous locomotor activity by 35% and 36%, respectively, 6 h post irradiation. In contrast, the motivated behavior of social exploration was un-impacted by gamma radiation. Examination of pro-inflammatory cytokine gene transcripts in the brain demonstrated that gamma radiation increased hippocampal TNF-α expression as early as 4 h post-irradiation. This was coupled to subsequent increases in IL-1RA (8 h and 12 h post irradiation) in the cortex and hippocampus and reductions in activity-regulated cytoskeleton-associated protein (Arc) (24 h post irradiation) in the cortex. Finally, restraint stress was a significant modulator of the neuroimmune response to radiation blocking the ability of 200 cGy gamma radiation from impairing locomotor activity and altering the brain-based inflammatory response to irradiation. Taken together, these findings indicate that low-dose ionizing radiation rapidly activates the neuroimmune system potentially causing early onset fatigue-like symptoms in mice. PMID:21958477

Spectral analysis of paramagnetic centers induced in human tooth enamel by x-rays and gamma radiation

NASA Astrophysics Data System (ADS)

Kirillov, V. A.; Kuchuro, I. I.

2010-03-01

Based on study of spectral and relaxation characteristics, we have established that paramagnetic centers induced in tooth enamel by x-rays and gamma radiation are identical in nature. We show that for the same exposure dose, the intensity of the electron paramagnetic resonance (EPR) signal induced by x-radiation with effective energy 34 keV is about an order of magnitude higher than the amplitude of the signal induced by gamma radiation. We have identified a three-fold attenuation of the EPR signal along the path of the x-radiation from the buccal to the lingual side of a tooth, which is evidence that the individual had undergone diagnostic x-ray examination of the dentition or skull. We have shown that the x-ray exposure doses reconstructed from the EPR spectra are an order of magnitude higher than the applied doses, while the dose loads due to gamma radiation are equal to the applied doses. The data obtained indicate that for adequate reconstruction of individual absorbed doses from EPR spectra of tooth enamel in the population subjected to the combined effect of x-radiation and accidental external gamma radiation as a result of the disaster at the Chernobyl nuclear power plant, we need to take into account the contribution to the dose load from diagnostic x-rays in examination of the teeth, jaw, or skull.

Rat Phantom Depth Dose Studies in Electron, X-ray, Gamma-Ray, and Reactor Radiation Fields

DTIC Science & Technology

1986-12-01

i©™D©/^ ^1[P@^T Rat phantom depth dose studies in electron , Xrayf gamma-ray, and reactor radiation fields M. Dooley D. M. Eagleson G. H. Zeman...energy electrons , bremsstrahlung, and mixed neutron/gamma radiation fields are sometimes used in radiobiological experiments employing rats. This report...have revealed differing sensitivities of experimental animals that have been exposed to cobalt-60 photons, high-energy electrons , high-energy X rays

Gamma radiation combined with cinnamon oil to maintain fish quality

NASA Astrophysics Data System (ADS)

Lyu, Fei; Zhang, Jing; Wei, Qianqian; Gao, Fei; Ding, Yuting; Liu, Shulai

2017-12-01

Effects of gamma radiation combined with cinnamon oil on quality of Northern Snakehead fish fillets were observed during storage at 4 °C. Fish fillets were treated with 1-5 kGy gamma radiation, 0.05-0.5% cinnamon oil or the combination of radiation and cinnamon oil. The antimicrobial activity increased with radiation dose and cinnamon oil concentration. During storage, the combination of 1 kGy radiation and 0.5% cinnamon oil displayed better inhibiting activities on aerobic plate counts, total volatile basic nitrogen, thiobarbituric acid reaction substances than 1 kGy radiation or 0.5% cinnamon oil used alone. Moreover, the combination could arrive at the similar inhibiting activities of cinnamon oil with higher concentration of 0.5% or radiation with higher dose of 5 kGy. Thus, the combination could decrease the radiation dose and cinnamon oil concentration without decreasing the effect of them on maintaining fish quality.

Effect of DNA-injuring agents on B. stearothermophilus. Report 1. High resistance of B. stearothermophilus to N-nitroso-N-methylurea, ultraviolet and gamma radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gainullina, S.M.; Gumanova, A.V.; Vinogradova, N.A.

1978-01-01

The effects of DNA-attacking agents on thermophilic microorganisms were investigated. Bacillus stearothermophilus were treated with N-nitroso-N-methylurea, ultraviolet radiation or gamma radiation. Survival curves were plotted.

SCHOTT optical glass in space

NASA Astrophysics Data System (ADS)

Jedamzik, Ralf; Petzold, Uwe

2017-09-01

Optical systems in space environment have to withstand harsh radiation. Radiation in space usually comes from three main sources: the Van Allen radiation belts (mainly electrons and protons); solar proton events and solar energetic particles (heavier ions); and galactic cosmic rays (gamma- or x-rays). Other heavy environmental effects include short wavelength radiation (UV) and extreme temperatures (cold and hot). Radiation can damage optical glasses and effect their optical properties. The most common effect is solarization, the decrease in transmittance by radiation. This effect can be observed for UV radiation and for gamma or electron radiation. Optical glasses can be stabilized against many radiation effects. SCHOTT offers radiation resistant glasses that do not show solarization effects for gamma or electron radiation. A review of SCHOTT optical glasses in space missions shows, that not only radiation resistant glasses are used in the optical designs, but also standard optical glasses. This publication finishes with a selection of space missions using SCHOTT optical glass over the last decades.

Gamma Radiation Effects on Peanut Skin Antioxidants

PubMed Central

de Camargo, Adriano Costa; de Souza Vieira, Thais Maria Ferreira; Regitano-D’Arce, Marisa Aparecida Bismara; Calori-Domingues, Maria Antonia; Canniatti-Brazaca, Solange Guidolin

2012-01-01

Peanut skin, which is removed in the peanut blanching process, is rich in bioactive compounds with antioxidant properties. The aims of this study were to measure bioactive compounds in peanut skins and evaluate the effect of gamma radiation on their antioxidant activity. Peanut skin samples were treated with 0.0, 5.0, 7.5, or 10.0 kGy gamma rays. Total phenolics, condensed tannins, total flavonoids, and antioxidant activity were evaluated. Extracts obtained from the peanut skins were added to refined-bleached-deodorized (RBD) soybean oil. The oxidative stability of the oil samples was determined using the Oil Stability Index method and compared to a control and synthetic antioxidants (100 mg/kg BHT and 200 mg/kg TBHQ). Gamma radiation changed total phenolic content, total condensed tannins, total flavonoid content, and the antioxidant activity. All extracts, gamma irradiated or not, presented increasing induction period (h), measured by the Oil Stability Index method, when compared with the control. Antioxidant activity of the peanut skins was higher than BHT. The present study confirmed that gamma radiation did not affect the peanut skin extracts’ antioxidative properties when added to soybean oil. PMID:22489142

Direct and indirect effects of ionizing radiation on grazer-phytoplankton interactions.

PubMed

Nascimento, Francisco J A; Bradshaw, Clare

2016-05-01

Risk assessment of exposure to radionuclides and radiation does not usually take into account the role of species interactions. We investigated how the transfer of carbon between a primary producer, Raphidocelis subcapitata, and a consumer, Daphnia magna, was affected by acute exposure to gamma radiation. In addition to unexposed controls, different treatments were used where: a) only D. magna (Z treatment); b) only R. subcapitata (P treatment) and c) both D. magna and R. subcapitata (ZP treatment) were exposed to one of three acute doses of gamma radiation (5, 50 and 100 Gy). We then compared differences among treatments for three endpoints: incorporation of carbon by D. magna, D. magna growth and R. subcapitata densities. Carbon incorporation was affected by which combination of species was irradiated and by the radiation dose. Densities of R. subcapitata at the end of the experiment were also affected by which species had been exposed to radiation. Carbon incorporation by D. magna was significantly lower in the Z treatment, indicating reduced grazing, an effect stronger with higher radiation doses, possibly due to direct effects of gamma radiation. Top-down indirect effects of this reduced grazing were also seen as R. subcapitata densities increased in the Z treatment due to decreased herbivory. The opposite pattern was observed in the P treatment where only R. subcapitata was exposed to gamma radiation, while the ZP treatment showed intermediate results for both endpoints. In the P treatments, carbon incorporation by D. magna was significantly higher than in the other treatments, suggesting a higher grazing pressure. This, together with direct effects of gamma radiation on R. subcapitata, probably significantly decreased phytoplankton densities in the P treatment. Our results highlight the importance of taking into account the role of species interactions when assessing the effects of exposure to gamma radiation in aquatic ecosystems. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Reflectivity of linear and nonlinear gamma radiated apodized chirped Bragg grating under ocean

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamdalla, Taymour A.; Faculty of Science, Tabuk University, Tabuk

In this paper, the effect Co{sup 60} gamma radiation is investigated on the effective refractive index of apodized chirped Bragg grating. Nine apodization profiles are considered. Comparison between the reflectivity of the gamma radiated and non radiated fiber Bragg grating has been carried out. The electric field of signals propagating through the apodized chirped fiber Bragg grating (ACFBG) is first calculated from which, new values for the refractive index are determined. The nonlinear effects appear on the ACFBG reflectivity. The effect of nonlinearity and undersea temperature and pressure on the grating is also studied.

Application of whole-body personal TL dosemeters in mixed field beta-gamma radiation.

PubMed

Ciupek, K; Aksamit, D; Wołoszczuk, K

2014-11-01

Application of whole-body personal TL dosemeters based on a high-sensitivity LiF:Mg,Cu,P (MCP-N) in mixed field beta-gamma radiation has been characterised. The measurements were carried out with (90)Sr/(90)Y, (85)Kr and (137)Cs point sources to calculate the energy response and linearity of the TLD response in a dose range of 0.1-30 mSv. From the result, calibration curves were obtained, enabling the readout of individual dose equivalent Hp(10) from gamma radiation and Hp(0.07) from beta radiation in mixed field beta-gamma. Limitation of the methodology and its application are presented and discussed. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Use of a solar panel as a directionally sensitive large-area radiation monitor for direct and scattered x-rays and gamma-rays.

PubMed

Abdul-Majid, S

1987-01-01

The characteristics of a 25.4 X 91 cm solar cell panel used as an x-ray and gamma-ray radiation monitor are presented. Applications for monitoring the primary x-ray beam are described at different values of operating currents and voltages as well as for directional dependence of scattered radiation. Other applications in gamma-ray radiography are also given. The detector showed linear response to both x-ray and gamma-ray exposures. The equipment is rigid, easy to use, relatively inexpensive and requires no power supply or any complex electronic equipment.

Cosmic rays, gamma rays and synchrotron radiation from the Galaxy

DOE PAGES

Orlando, Elena

2012-07-30

Galactic cosmic rays (CR), interstellar gamma-ray emission and synchrotron radiation are related topics. CR electrons propagate in the Galaxy and interact with the interstellar medium, producing inverse-Compton emission measured in gamma rays and synchrotron emission measured in radio. I present an overview of the latest results with Fermi/LAT on the gamma-ray diffuse emission induced by CR nuclei and electrons. Then I focus on the recent complementary studies of the synchrotron emission in the light of the latest gamma-ray results. Relevant observables include spectral indices and their variations, using surveys over a wide range of radio frequencies. As a result, thismore » paper emphasizes the importance of using the parallel study of gamma rays and synchrotron radiation in order to constrain the low-energy interstellar CR electron spectrum, models of propagation of CRs, and magnetic fields.« less

[Hematopoiesis during remote period after acute radiation syndrome].

PubMed

Kotenko, K V; Bushmanov, A Iu; Suvorova, L A; Galstian, I A; Nadezhina, N M; Nugis, V Iu

2011-01-01

Based on the long (19.7 +/- 1.8 year) hemopoiesis follow-up study in 152 patients after acute radiation syndrome (ARS) as a result of exposure to gamma-, gamma-beta and gamma-eta radiation in a wide dose range (1.2-9.8 Gy) it was detected that cytopenia appears in the late consequences period: thrombocytopenia was found in 26.9% cases, leukocytopenia, neutropenia and lymphocytopenia--in 13.1% patients. A higher ARS degree causes the increase of various disorders (cytopenia and cytosis) in the late period. It reflects a tight interrelation between blood cell contents and radiation dose. Frequency of cytopenias increases if such somatic disorders: persistent hepatitis, hepatic cirrhosis and late radiation ulcers as appear.

Short-term variability of gamma radiation at the ARM Eastern North Atlantic facility (Azores).

PubMed

Barbosa, S M; Miranda, P; Azevedo, E B

2017-06-01

This work addresses the short-term variability of gamma radiation measured continuously at the Eastern North Atlantic (ENA) facility located in the Graciosa island (Azores, 39N; 28W), a fixed site of the Atmospheric Radiation Measurement programme (ARM). The temporal variability of gamma radiation is characterized by occasional anomalies over a slowly-varying signal. Sharp peaks lasting typically 2-4 h are coincident with heavy precipitation and result from the scavenging effect of precipitation bringing radon progeny from the upper levels to the ground surface. However the connection between gamma variability and precipitation is not straightforward as a result of the complex interplay of factors such as the precipitation intensity, the PBL height, the cloud's base height and thickness, or the air mass origin and atmospheric concentration of sub-micron aerosols, which influence the scavenging processes and therefore the concentration of radon progeny. Convective precipitation associated with cumuliform clouds forming under conditions of warming of the ground relative to the air does not produce enhancements in gamma radiation, since the drop growing process is dominated by the fast accretion of liquid water, resulting in the reduction of the concentration of radionuclides by dilution. Events of convective precipitation further contribute to a reduction in gamma counts by inhibiting radon release from the soil surface and by attenuating gamma rays from all gamma-emitting elements on the ground. Anomalies occurring in the absence of precipitation are found to be associated with a diurnal cycle of maximum gamma counts before sunrise decreasing to a minimum in the evening, which are observed in conditions of thermal stability and very weak winds enabling the build-up of near surface radon progeny during the night. Copyright © 2017 Elsevier Ltd. All rights reserved.

Method and system for determining radiation shielding thickness and gamma-ray energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klann, Raymond T.; Vilim, Richard B.; de la Barrera, Sergio

2015-12-15

A system and method for determining the shielding thickness of a detected radiation source. The gamma ray spectrum of a radiation detector is utilized to estimate the shielding between the detector and the radiation source. The determination of the shielding may be used to adjust the information from known source-localization techniques to provide improved performance and accuracy of locating the source of radiation.

Radiation-assisted grafting of vinylidene chloride onto high-density polyethylene

NASA Astrophysics Data System (ADS)

Nagesh, N.; Dokhale, P. A.; Bhoraskar, V. N.

1999-06-01

6 MeV electrons and Co-60 icons/Journals/Common/gamma" ALT="gamma" ALIGN="TOP"/>-rays were used for grafting vinylidene chloride (VDC) onto high-density polyethylene (HDPE) samples. The HDPE samples were immersed in vinylidene chloride and irradiated either with Co-60 icons/Journals/Common/gamma" ALT="gamma" ALIGN="TOP"/>-rays or with 6 MeV electrons. In both cases, the radiation dose was varied in the range 1.25-7.5 kGy. The grafted samples were characterized by IR spectroscopy to obtain information about the chemical bonds and with the 14 MeV neutron activation analysis technique for estimating the number of chlorine atoms. The formation of stable bonds between the VDC molecules and the polymer chains could be achieved either with 6 MeV electrons or with Co-60 icons/Journals/Common/gamma" ALT="gamma" ALIGN="TOP"/>-rays. Both the number of chlorine atoms and the sample-surface conductivity increased with the radiation dose but the increases achieved with 6 MeV electrons were greater than those achieved with Co-60 icons/Journals/Common/gamma" ALT="gamma" ALIGN="TOP"/>-rays.

Results from Preliminary Checks on AmBe Neutron Source Number 71

DTIC Science & Technology

2011-02-01

radiation and additional lead shielding was used to shield against gamma radiation emissions. Electronic dosimeters , the MGP DMC2000GN and Thermo EPD...DMC2000GN (S/N: 007395) and EPD-N2 (S/N: 07106323) electronic dosimeters were employed as these both are able to measure and record gamma and neutron...the AN/VDR-2 gamma radiation meter and Meridian Model 5085 neutron meter to confirm this and electronic dosimeters would be worn by personnel to

Gamma-Radiation-Induced Degradation of Actively Pumped Single-Mode Ytterbium-Doped Optical Laser - Postprint

DTIC Science & Technology

2015-01-01

evaluated using the cobalt (Co)-60 gamma irradiation facility at The Ohio State University. A radiation dose rate of 43 krad(Si)/hr was used to expose the...Table 1. Description of the optical fibers used for in-situ analysis of the radiation damage Optical fiber Core Dopant Core/cladding diameters (μm...University is a pool-type gamma irradiation facility using a common cobalt cylindrical rod irradiator submerged 20 feet into a water tank. A

Improving the radiation hardness of graphene field effect transistors

DOE PAGES

Alexandrou, Konstantinos; Masurkar, Amrita; Edrees, Hassan; ...

2016-10-11

Ionizing radiation poses a significant challenge to the operation and reliability of conventional silicon-based devices. In this paper, we report the effects of gamma radiation on graphene field-effect transistors (GFETs), along with a method to mitigate those effects by developing a radiation-hardened version of our back-gated GFETs. We demonstrate that activated atmospheric oxygen from the gamma ray interaction with air damages the semiconductor device, and damage to the substrate contributes additional threshold voltage instability. Our radiation-hardened devices, which have protection against these two effects, exhibit minimal performance degradation, improved stability, and significantly reduced hysteresis after prolonged gamma radiation exposure. Finally,more » we believe this work provides an insight into graphene's interactions with ionizing radiation that could enable future graphene-based electronic devices to be used for space, military, and other radiation-sensitive applications.« less

Improving the radiation hardness of graphene field effect transistors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alexandrou, Konstantinos; Masurkar, Amrita; Edrees, Hassan

Ionizing radiation poses a significant challenge to the operation and reliability of conventional silicon-based devices. In this paper, we report the effects of gamma radiation on graphene field-effect transistors (GFETs), along with a method to mitigate those effects by developing a radiation-hardened version of our back-gated GFETs. We demonstrate that activated atmospheric oxygen from the gamma ray interaction with air damages the semiconductor device, and damage to the substrate contributes additional threshold voltage instability. Our radiation-hardened devices, which have protection against these two effects, exhibit minimal performance degradation, improved stability, and significantly reduced hysteresis after prolonged gamma radiation exposure. Finally,more » we believe this work provides an insight into graphene's interactions with ionizing radiation that could enable future graphene-based electronic devices to be used for space, military, and other radiation-sensitive applications.« less

Energy spectrum of extragalactic gamma-ray sources

NASA Technical Reports Server (NTRS)

Protheroe, R. J.

1985-01-01

The result of Monte Carlo electron photon cascade calculations for propagation of gamma rays through regions of extragalactic space containing no magnetic field are given. These calculations then provide upper limits to the expected flux from extragalactic sources. Since gamma rays in the 10 to the 14th power eV to 10 to the 17th power eV energy range are of interest, interactions of electrons and photons with the 3 K microwave background radiation are considered. To obtain an upper limit to the expected gamma ray flux from sources, the intergalactic field is assumed to be so low that it can be ignored. Interactions with photons of the near-infrared background radiation are not considered here although these will have important implications for gamma rays below 10 to the 14th power eV if the near infrared background radiation is universal. Interaction lengths of electrons and photons in the microwave background radiation at a temperature of 2.96 K were calculated and are given.

Directional gamma detector

DOEpatents

LeVert, Francis E.; Cox, Samson A.

1981-01-01

An improved directional gamma radiation detector has a collector sandwiched etween two layers of insulation of varying thicknesses. The collector and insulation layers are contained within an evacuated casing, or emitter, which releases electrons upon exposure to gamma radiation. Delayed electrons and electrons entering the collector at oblique angles are attenuated as they pass through the insulation layers on route to the collector.

Radiation-induced enzyme efflux from rat heart: sedentary animals. [Gamma radiation, lactate dehydrogenase, creative kinase, glutamate oxaloacetate transaminase

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacWilliam, L.D.; Bhakthan, N.M.G.

1976-01-01

Serum levels of lactate dehydrogenase, creatine kinase, and glutamate oxaloacetate transaminase show initial elevations within 12 hr of exposure to 2,000 rads of ..gamma..-radiation to the thoracic region of rats. Significant decreases in heart muscle homogenate levels of these enzymes parallel initial elevations in the serum and may suggest that enhanced leakage of enzymes is a consequence of radiation injury to heart muscle. Insignificant alterations in mitochondrial glutamate oxaloacetate transaminase levels after exposure indicate that in vivo injury to the mitochondria from therapeutic levels of ..gamma..-radiation is questionable. The results support the contention that ionizing radiation instigates alterations in themore » dynamic permeability of membranes, allowing leakage of biologically active material out of the injured cell.« less

Fermi Gamma-Ray Space Telescope: Science Highlights for the First 8 Months

NASA Technical Reports Server (NTRS)

Moiseev, Alexander

2010-01-01

The Fermi Gamma-ray Space Telescope was launched on June 11, 2008 and since August 2008 has successfully been conducting routine science observations of high energy phenomena in the gamma-ray sky. A number of exciting discoveries have been made during its first year of operation, including blazar flares, high-energy gamma-ray bursts, and numerous new,gamma-ray sources of different types, among them pulsars and Active Galactic Nuclei (AGN). fermi-LAT also performed accurate mea.<;urement of the diffuse gamma-radiation which clarifies the Ge V excess reported by EGRET almost 10 years ago, high precision measurement of the high energy electron spectrum, and other observations. An overview of the observatory status and recent results as of April 30, 2009, are presented. Key words: gamma-ray astronomy, cosmic rays, gamma-ray burst, pulsar, blazar. diffuse gamma-radiation

Evaluation of γ-radiation-induced DNA damage in two species of bivalves and their relative sensitivity using comet assay.

PubMed

Praveen Kumar, M K; Shyama, S K; Sonaye, B S; Naik, U Roshini; Kadam, S B; Bipin, P D; D'costa, A; Chaubey, R C

2014-05-01

Ionizing radiation is known to induce genetic damage in diverse groups of organisms. Under accidental situations, large quantities of radioactive elements get released into the environment and radiation emitted from these radionuclides may adversely affect both the man and the non-human biota. The present study is aimed (a) to know the genotoxic effect of gamma radiation on aquatic fauna employing two species of selected bivalves, (b) to evaluate the possible use of 'Comet assay' for detecting genetic damage in haemocytes of bivalves as a biomarker for environmental biomonitoring and also (c) to compare the relative sensitivity of two species of bivalves viz. Paphia malabarica and Meretrix casta to gamma radiation. The comet assays was optimized and validated using different concentrations (18, 32 and 56 mg/L) of ethyl methanesulfonate (EMS), a direct-acting reference genotoxic agent, to which the bivalves were exposed for various times (24, 48 and 72 h). Bivalves were irradiated (single acute exposure) with 5 different doses (viz. 2, 4, 6, 8 and 10 Gy) of gamma radiation and their genotoxic effects on the haemocytes were studied using the comet assay. Haemolymph was collected from the adductor muscle at 24, 48 and 72 h of both EMS-exposed and irradiated bivalves and comet assay was carried out using standard protocol. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA damage at different concentrations of EMS and all the doses of gamma radiation as compared to controls in both bivalve species. This showed a dose-dependent increase of genetic damage induced in bivalves by EMS as well as gamma radiation. Further, the highest DNA damage was observed at 24h. The damage gradually decreased with time, i.e. was smaller at 48 and 72 h than at 24h post irradiation in both species of bivalves. This may indicate repair of the damaged DNA and/or loss of heavily damaged cells as the post irradiation time advanced. The present study reveals that gamma radiation induces single strand breaks in DNA as measured by alkaline comet assay in bivalves and comet assay serves as a sensitive and rapid method to detect genotoxicity of gamma radiation. This study further indicates that both M. casta and P. malabarica exhibit almost identical sensitivity to gamma radiation as measured by DNA damage. Copyright © 2014 Elsevier B.V. All rights reserved.

Childhood leukemia incidence and exposure to indoor radon, terrestrial and cosmic gamma radiation.

PubMed

Evrard, Anne-Sophie; Hémon, Denis; Billon, Solenne; Laurier, Dominique; Jougla, Eric; Tirmarche, Margot; Clavel, Jacqueline

2006-06-01

This study was undertaken to evaluate the ecological association between terrestrial and cosmic gamma radiation, indoor radon, and acute leukemia incidence among children under 15 y of age. From 1990 to 2001, 5,330 cases of acute leukemia were registered by the French National Registry of Childhood Leukemia and Lymphoma. Exposure to terrestrial gamma radiation was based on measurements, using thermoluminescent dosimeters, at about 1,000 sites covering all the "Départements." In addition, 8,737 indoor terrestrial gamma dose rate measurements covering 62% of the "Départements" and 13,240 indoor radon concentration measurements covering all the "Départements" were made during a national campaign. Cosmic ray doses were estimated in each of the 36,363 "Communes" of France. There was no evidence of an ecological association between terrestrial gamma dose (range: 0.22-0.90 mSv y) or total gamma dose (range: 0.49-1.28 mSv y) and childhood acute leukemia incidence, for acute myeloid leukemia (AML) or for acute lymphoblastic leukemia (ALL), in univariate or multivariate regression analyses including indoor radon. A significant positive association between indoor radon (range: 22-262 Bq m) and AML incidence among children was observed and remained significant in multivariate regression analyses including either terrestrial gamma dose [SIR per 100 Bq m = 1.29 (1.09-1.53)] or total gamma dose [SIR per 100 Bq m = 1.29 (1.09-1.53)]. The study showed no ecological association between terrestrial gamma radiation and childhood leukemia for the range of variation in gamma dose rates observed in France. The moderate ecological association between childhood AML incidence and indoor radon does not appear to be confounded by terrestrial gamma dose.

Poster - 11: Radiation barrier thickness calculations for the GammaPod

DOE Office of Scientific and Technical Information (OSTI.GOV)

La Russa, Daniel; Vandervoort, Eric; Wilkins, Davi

A consortium of radiotherapy centers in North America is in the process of evaluating a novel new {sup 60}Co teletherapy device, called the GammaPod™ (Xcision Medical Systems, Columbia Maryland), designed specifically for breast SBRT. The GammaPod consists of 36 collimated {sup 60}Co sources with a total activity of 4320 Ci. The sources are housed in a hemispherical source carrier that rotates during treatment to produce a cylindrically symmetric cone of primary beam spanning 16° – 54° degrees from the horizontal. This unique beam geometry presents challenges when designing or evaluating room shielding for the purposes of meeting regulatory requirements, andmore » for ensuring the safety of staff and the public in surrounding areas. Conventional methods for calculating radiation barrier thicknesses have been adapted so that barrier transmission factors for the GammaPod can be determined from a few relevant distances and characteristics of the primary beam. Simple formalisms have been determined for estimating shielding requirements for primary radiation (with a rotating and non-rotating source carrier), patient-scattered radiation, and leakage radiation. When making worst case assumptions, it was found that conventional barrier thicknesses associated with linac treatment suites are sufficient for shielding all sources of radiation from the GammaPod.« less

Extraction, purification and anti-radiation activity of persimmon tannin from Diospyros kaki L.f.

PubMed

Zhou, Zhide; Huang, Yong; Liang, Jintao; Ou, Minglin; Chen, Jiejing; Li, Guiyin

2016-10-01

In this study, persimmon tannin was extracted from Diospyros kaki L.f. using ultrasound-assisted extraction and purified by D101 macroporous resin column chromatography and polysulfone ultrafiltration membrane. The tannin content of the final persimmon tannin extracts was attained to 39.56% calculated as catechin equivalents. Also, the radioprotective effects of persimmon tannin for HEK 293T cells proliferation and apoptosis after Gamma irradiation were investigated by CCK-8, Hoechst 33258 staining, flow cytometry assay and intracellular reactive oxygen species assay (ROS). Persimmon tannin was pre-incubated with HEK 293T cells for 12 h prior to Gamma irradiation. It was found that pretreatment with persimmon tannin increased cell viability and inhibited generation of Gamma-radiation induced ROS in HEK 293T cells exposed to 8 Gy Gamma-radiation. The percentage of apoptotic cells were only 6.7% when the radiation dose was 8 Gy and pretreated with 200 μg/ml of persimmon tannin. All these results indicated that persimmon tannin offered a potent radioprotective effect on cell vitality and cell apoptosis of Gamma-radiation exposure in HEK 293T cells. This study would serve as a pre-clinical evaluation of persimmon tannin for use in people with radiation protection. Copyright © 2016 Elsevier Ltd. All rights reserved.

Radiation tolerance in the tardigrade Milnesium tardigradum.

PubMed

Horikawa, Daiki D; Sakashita, Tetsuya; Katagiri, Chihiro; Watanabe, Masahiko; Kikawada, Takahiro; Nakahara, Yuichi; Hamada, Nobuyuki; Wada, Seiichi; Funayama, Tomoo; Higashi, Seigo; Kobayashi, Yasuhiko; Okuda, Takashi; Kuwabara, Mikinori

2006-12-01

Tardigrades are known to survive high doses of ionizing radiation. However, there have been no reports about radiation effects in tardigrades under culture conditions. In this study, we investigated tolerance of the tardigrade, Milnesium tardigradum, against gamma-rays and heavy ions by determining short-term or long-term survival, and reproductive ability after irradiation. Hydrated and anhydrobiotic animals were exposed to gamma-rays (1000 - 7000 Gy) or heavy ions (1000 - 8000 Gy) to evaluate short-term survival at 2, 24 and 48 h post-irradiation. Long-term survival and reproduction were observed up to 31 days after irradiation with gamma-rays (1000 - 4000 Gy). At 48 h after irradiation, median lethal doses were 5000 Gy (gamma-rays) and 6200 Gy (heavy ions) in hydrated animals, and 4400 Gy (gamma-rays) and 5200 Gy (heavy ions) in anhydrobiotic ones. Gamma-irradiation shortened average life span in a dose-dependent manner both in hydrated and anhydrobiotic groups. No irradiated animals laid eggs with one exception in which a hydrated animal irradiated with 2000 Gy of gamma-rays laid 3 eggs, and those eggs failed to hatch, whereas eggs produced by non-irradiated animals hatched successfully. M. tardigradum survives high doses of ionizing radiation in both hydrated and anhydrobiotic states, but irradiation with >1000 Gy makes them sterile.

Secondary production of neutral pi-mesons and the diffuse galactic gamma radiation

NASA Technical Reports Server (NTRS)

Dermer, C. D.

1986-01-01

Isobaric and scaling model predictions of the secondary spectra of neutral pi-mesons produced in proton-proton collisions, at energies between threshold and a few GeV, are compared on the basis of accelerator data and found to show the isobaric model to be superior. This model is accordingly used, in conjuction with a scaling model representation at high energies, in a recalculation of the pi exp (0) gamma-radiation's contribution to the diffuse galactic gamma background; the cosmic ray-induced production of photons (whose energy exceeds 100 MeV) by such radiation occurs at a rate of 1.53 x 10 to the -25 photons/(s-H atom). These results are compared with previous calculations of this process as well as with COS-B observations of the diffuse galactic gamma-radiation.

Extract of Xylopia aethiopica (Annonaceae) protects against gamma-radiation induced testicular damage in Wistar rats.

PubMed

Adaramoye, Oluwatosin Adekunle; Adedara, Isaac Adegboyega; Popoola, Bosede; Farombi, Ebenezer Olatunde

2010-01-01

Ionizing radiation is an important environmental risk factor and, a major therapeutic agent for cancer treatment. This study was designed to evaluate the protective effect of extract of Xylopia aethiopica (XA) on gamma-radiation-induced testicular damage in rats. Vitamin C (VC) served as the reference antioxidant during the study. The study consists of 4 groups of 11 rats each. Group I received corn oil (vehicle), groups II and IV were pretreated with XA (250 mg/kg) and VC (250mg/kg) for 6 weeks before and 8 weeks after exposure to gamma-radiation; group III was exposed to a single dose of gamma-radiation (5 Gy). Biochemical analysis revealed that gamma-irradiation caused a significant increase (p < .05) in serum and testicular lipid peroxidation (LPO) levels by 217% and 221%, respectively. Irradiated rats had markedly decreased testicular catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST), and reduced glutathione (GSH) levels. Irradiation resulted in 59% and 40% decreases in spermatozoa motility and live/dead sperm count, respectively, and a 161% increase in total sperm abnormalities. Histologically, testes of the irradiated rats showed extensive degenerative changes in the seminiferous tubules and defoliation of spermatocytes. Supplementation of XA and VC reversed the adverse effects of gamma-radiation on biochemical and histological indices of the rats. These findings demonstrated that Xylopia aethiopica has a protective effect by inhibiting oxidative damage in testes of irradiated rats.

Composition for radiation shielding

DOEpatents

Kronberg, J.W.

1994-08-02

A composition for use as a radiation shield is disclosed. The shield has a depleted uranium core for absorbing gamma rays and a bismuth coating for preventing chemical corrosion and absorbing gamma rays. Alternatively, a sheet of gadolinium may be positioned between the uranium core and the bismuth coating for absorbing neutrons. The composition is preferably in the form of a container for storing materials that emit radiation such as gamma rays and neutrons. The container is preferably formed by casting bismuth around a pre-formed uranium container having a gadolinium sheeting, and allowing the bismuth to cool. The resulting container is a structurally sound, corrosion-resistant, radiation-absorbing container. 2 figs.

Composition for radiation shielding

DOEpatents

Kronberg, James W.

1994-01-01

A composition for use as a radiation shield. The shield has a depleted urum core for absorbing gamma rays and a bismuth coating for preventing chemical corrosion and absorbing gamma rays. Alternatively, a sheet of gadolinium may be positioned between the uranium core and the bismuth coating for absorbing neutrons. The composition is preferably in the form of a container for storing materials that emit radiation such as gamma rays and neutrons. The container is preferably formed by casting bismuth around a pre-formed uranium container having a gadolinium sheeting, and allowing the bismuth to cool. The resulting container is a structurally sound, corrosion-resistant, radiation-absorbing container.

Unitary scintillation detector and system

DOEpatents

McElhaney, Stephanie A.; Chiles, Marion M.

1994-01-01

The invention is a unitary alpha, beta, and gamma scintillation detector and system for sensing the presence of alpha, beta, and gamma radiations selectively or simultaneously. The scintillators are mounted in a light-tight housing provided with an entrance window for admitting alpha, beta, and gamma radiation and excluding ambient light from the housing. Light pulses from each scintillator have different decay constants that are converted by a photosensitive device into corresponding differently shaped electrical pulses. A pulse discrimination system identifies the electrical pulses by their respective pulse shapes which are determined by decay time. The identified electrical pulses are counted in separate channel analyzers to indicate the respective levels of sensed alpha, beta, and gamma radiations.

Unitary scintillation detector and system

DOEpatents

McElhaney, S.A.; Chiles, M.M.

1994-05-31

The invention is a unitary alpha, beta, and gamma scintillation detector and system for sensing the presence of alpha, beta, and gamma radiations selectively or simultaneously. The scintillators are mounted in a light-tight housing provided with an entrance window for admitting alpha, beta, and gamma radiation and excluding ambient light from the housing. Light pulses from each scintillator have different decay constants that are converted by a photosensitive device into corresponding differently shaped electrical pulses. A pulse discrimination system identifies the electrical pulses by their respective pulse shapes which are determined by decay time. The identified electrical pulses are counted in separate channel analyzers to indicate the respective levels of sensed alpha, beta, and gamma radiations. 10 figs.

Handheld CZT radiation detector

DOEpatents

Murray, William S.; Butterfield, Kenneth B.; Baird, William

2004-08-24

A handheld CZT radiation detector having a CZT gamma-ray sensor, a multichannel analyzer, a fuzzy-logic component, and a display component is disclosed. The CZT gamma-ray sensor may be a coplanar grid CZT gamma-ray sensor, which provides high-quality gamma-ray analysis at a wide range of operating temperatures. The multichannel analyzer categorizes pulses produce by the CZT gamma-ray sensor into channels (discrete energy levels), resulting in pulse height data. The fuzzy-logic component analyzes the pulse height data and produces a ranked listing of radioisotopes. The fuzzy-logic component is flexible and well-suited to in-field analysis of radioisotopes. The display component may be a personal data assistant, which provides a user-friendly method of interacting with the detector. In addition, the radiation detector may be equipped with a neutron sensor to provide an enhanced mechanism of sensing radioactive materials.

Teaching about Natural Background Radiation

ERIC Educational Resources Information Center

Al-Azmi, Darwish; Karunakara, N.; Mustapha, Amidu O.

2013-01-01

Ambient gamma dose rates in air were measured at different locations (indoors and outdoors) to demonstrate the ubiquitous nature of natural background radiation in the environment and to show that levels vary from one location to another, depending on the underlying geology. The effect of a lead shield on a gamma radiation field was also…

Nature of gamma rays background radiation in new and old buildings of Qatar University

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Houty, L.; Abou-Leila, H.; El-Kameesy, S.

Measurements and analysis of gamma-background radiation spectrum in four different places of Qatar University campus were performed at the energy range 10 keV-3 MeV using hyper pure Ge-detector. The dependence of the detector absolute photopeak efficiency on gamma-ray energies was determined and correction of the data for that was also done. The absorbed dose for each gamma line was calculated and an estimation of the total absorbed dose for the detected gamma lines in the four different places was obtained. Comparison with other results was also performed.

Gamma radiation effects on physical properties of parchment documents: Assessment of Dmax

NASA Astrophysics Data System (ADS)

Nunes, Inês; Mesquita, Nuno; Cabo Verde, Sandra; João Trigo, Maria; Ferreira, Armando; Manuela Carolino, Maria; Portugal, António; Luísa Botelho, Maria

2012-12-01

Parchments are important documents that give testimony for History; therefore these materials should be respected and preserved. Considering incremental biodeterioration problems that have to be faced daily, the Archive of the University of Coimbra (AUC) is involved in different scientific projects in order to evaluate and determine new methods for document decontamination and preservation. The aim of this study was to evaluate gamma radiation effects on the colour and texture of the AUC parchment documents. The assessment of these effects was used to estimate the maximum gamma radiation dose (Dmax) that could guarantee parchment documents' decontamination treatment, without significant alteration of their physical properties. Parchment samples were exposed to gamma radiation doses ranging from 10 to 30 kGy. The texture and colour of samples were assessed before and after the irradiation procedure, using a texture analyser and an electronic colorimeter. Hardness and springiness were determined based on texture spectra. Lightness (L*), Chroma (C), greenness vs. redness (a*) and yellowness vs. blueness (b*) values were obtained from colorimetric measures. Results indicate no significant effects of gamma radiation on the texture and colour of parchment for the studied doses.

Some neutron and gamma radiation characteristics of plutonium cermet fuel for isotopic power sources

NASA Technical Reports Server (NTRS)

Neff, R. A.; Anderson, M. E.; Campbell, A. R.; Haas, F. X.

1972-01-01

Gamma and neutron measurements on various types of plutonium sources are presented in order to show the effects of O-17, O-18 F-19, Pu-236, age of the fuel, and size of the source on the gamma and neutron spectra. Analysis of the radiation measurements shows that fluorine is the main contributor to the neutron yields from present plutonium-molybdenum cermet fuel, while both fluorine and Pu-236 daughters contribute significantly to the gamma ray intensities.

Compton effect thermally activated depolarization dosimeter

DOEpatents

Moran, Paul R.

1978-01-01

A dosimetry technique for high-energy gamma radiation or X-radiation employs the Compton effect in conjunction with radiation-induced thermally activated depolarization phenomena. A dielectric material is disposed between two electrodes which are electrically short circuited to produce a dosimeter which is then exposed to the gamma or X radiation. The gamma or X-radiation impinging on the dosimeter interacts with the dielectric material directly or with the metal composing the electrode to produce Compton electrons which are emitted preferentially in the direction in which the radiation was traveling. A portion of these electrons becomes trapped in the dielectric material, consequently inducing a stable electrical polarization in the dielectric material. Subsequent heating of the exposed dosimeter to the point of onset of ionic conductivity with the electrodes still shorted through an ammeter causes the dielectric material to depolarize, and the depolarization signal so emitted can be measured and is proportional to the dose of radiation received by the dosimeter.

Fiber fed x-ray/gamma ray imaging apparatus

DOEpatents

Hailey, C.J.; Ziock, K.P.

1992-06-02

X-ray/gamma ray imaging apparatus is disclosed for detecting the position, energy, and intensity of x-ray/gamma ray radiation comprising scintillation means disposed in the path of such radiation and capable of generating photons in response to such radiation; first photodetection means optically bonded to the scintillation means and capable of generating an electrical signal indicative of the intensity, and energy of the radiation detected by the scintillation means; second photodetection means capable of generating an electrical signal indicative of the position of the radiation in the radiation pattern; and means for optically coupling the scintillation means to the second photodetection means. The photodetection means are electrically connected to control and storage means which may also be used to screen out noise by rejecting a signal from one photodetection means not synchronized to a signal from the other photodetection means; and also to screen out signals from scattered radiation. 6 figs.

Product sterilization. Why industry uses radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sparks, B.J.

1984-09-01

Industry uses gamma radiation sterilization because of its superior reliability, safety, and cost savings over the EO fumigation method. EO has many processing variables and is toxic and expensive. The Environmental Protection Agency has recently declared EO to be both mutagenic and carcinogenic. The residual EO in hospital products has been reported to adversely affect hospital workers. Unlike EO fumigation, radiation sterilization imparts no toxic residuals. The coloration and embrittlement problems experienced earlier with some products sterilized by gamma radiation are being overcome with the introduction of new manufacturing materials and lower radiation dosages. Other benefits of radiation sterilization includemore » the option of sterilizing some materials that could not otherwise be sterilized and using new types of packaging to better protect the products and increase shelf-life. The emphasis now being placed on cost containment for health care products will be another significant part of the answer to why industry uses gamma radiation sterilization.« less

[Shielding effect of clinical X-ray protector and lead glass against annihilation radiation and gamma rays of 99mTc].

PubMed

Fukuda, Atsushi; Koshida, Kichiro; Yamaguchi, Ichiro; Takahashi, Masaaki; Kitabayashi, Keitarou; Matsubara, Kousuke; Noto, Kimiya; Kawabata, Chikako; Nakagawa, Hiroto

2004-12-01

Various pharmaceutical companies in Japan are making radioactive drugs available for positron emission tomography (PET) in hospitals without a cyclotron. With the distribution of these drugs to hospitals, medical check-ups and examinations using PET are expected to increase. However, the safety guidelines for radiation in the new deployment of PET have not been adequately improved. Therefore, we measured the shielding effect of a clinical X-ray protector and lead glass against annihilation radiation and gamma rays of (99m)Tc. We then calculated the shielding effect of a 0.25 mm lead protector, 1 mm lead, and lead glass using the EGS4 (Electron Gamma Shower Version 4) code. The shielding effects of 22-mm lead glass against annihilation radiation and gamma rays of (99m)Tc were approximately 31.5% and 93.3%, respectively. The clinical X-ray protector against annihilation radiation approximately doubled the skin-absorbed dose.

The Use of Gamma Radiation for the Treatment of Cultural Heritage in the Argentine National Atomic Energy Commission: Past, Present, and Future.

PubMed

Calvo, Ana Maria Del Carmen; Docters, Andrea; Miranda, María Virginia; Saparrat, Mario Carlos Nazareno

2017-02-01

The use of gamma radiation for treating biodeteriorated cultural heritage on paper has been studied at the Comisión Nacional de Energía Atómica-CNEA (Argentina) since 2001. In order to preserve books, publications, and documents that have been attacked by insects or fungi, gamma radiation techniques have been used at CNEA. The activities include basic research as well as their applications in infected documents and papers currently used in libraries and archives. New papers were subjected to accelerated ageing in order to evaluate the effects of gamma radiation on their physical and mechanical properties. Current studies include resistance to radiation in two batches of highly cellulolytic fungi, associated with indoor environment. They are present in papers and adhesives used for conservation purposes at the Laboratory of Preventive Conservation and Restoration of Documents. A joint study has been started in CNEA with the National University of La Plata.

UV EFFECTS IN TOOTH ENAMEL AND THEIR POSSIBLE APPLICATION IN EPR DOSIMETRY WITH FRONT TEETH

PubMed Central

Sholom, S.; Desrosiers, M.; Chumak, V.; Luckyanov, N.; Simon, S.L.; Bouville, A.

2009-01-01

The effects of ultraviolet (UV) radiation on ionizing radiation biodosimetry were studied in human tooth enamel samples using the technique of electron paramagnetic resonance (EPR) in X-band. For samples in the form of grains, UV-specific EPR spectra were spectrally distinct from that produced by exposure to gamma radiation. From larger enamel samples, the UV penetration depth was determined to be in the 60–120 μm range. The difference in EPR spectra from UV exposure and from exposure to gamma radiation samples was found to be a useful marker of UV equivalent dose (defined as the apparent contribution to the gamma dose in mGy that results from UV radiation absorption) in tooth enamel. This concept was preliminarily tested on front teeth from inhabitants of the region of the Semipalatinsk Nuclear Test Site (Kazakhstan) who might have received some exposure to gamma radiation from the nuclear tests conducted there as well as from normal UV radiation in sunlight. The technique developed here to quantify and subtract the UV contribution to the measured tooth is currently limited to cumulative dose measurements with a component of UV equivalent dose equal to or greater than 300 mGy. PMID:20065706

Shelf life extension of fresh turmeric ( Curcuma longa L.) using gamma radiation

NASA Astrophysics Data System (ADS)

Dhanya, R.; Mishra, B. B.; Khaleel, K. M.; Cheruth, Abdul Jaleel

2009-09-01

Gamma radiation processing was found to extend shelf life of fresh turmeric. A 5 kGy radiation dose and 10 °C storage temperature was found to keep peeled turmeric samples microbe free and acceptable until 60 days of storage. The control sample without radiation treatment spoiled within a week of storage. The changes in color, texture and moisture content of fresh turmeric due to radiation treatment were found to be statistically insignificant.

Limits to the radiative decays of neutrinos and axions from gamma-ray observations of SN 1987A

NASA Technical Reports Server (NTRS)

Kolb, Edward W.; Turner, Michael S.

1989-01-01

Gamma-ray observations obtained by the SMM gamma-ray spectrometer in the energy range 4.1-6.4 MeV are used to provide limits on the possible radiative decay of neutrinos and axions emitted by SN 1987A. For branching ratio values for the radiative decay modes of less than about 0.0001, the present limits are more stringent than those based upon the photon flux from decaying relic neutrinos. The data are also used to set an axion mass limit.

Effective gamma-ray doses due to natural radiation from soils of southeastern Brazil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silveira, M. A. G.; Moreira, R. H.; Bellini, B. S.

2010-08-04

We have used gamma-ray spectrometry to study the distribution of natural radiation from soils of southeastern Brazil: Billings reservoir, Sao Bernardo do Campo Parks, Diadema Parks, Interlagos region, Sao Paulo, and soil from Sao Paulo and Rio de Janeiro beaches. In most of the regions studied we have found that the dose due the external exposure to gamma-rays, proceeding from natural terrestrial elements, are between the values 0.3 and 0.6 mSv/year, established by the United Nations Scientific Committee on the Effects of Atomic Radiation.

Payload dose rate from direct beam radiation and exhaust gas fission products. [for nuclear engine for rocket vehicles

NASA Technical Reports Server (NTRS)

Capo, M. A.; Mickle, R.

1975-01-01

A study was made to determine the dose rate at the payload position in the NERVA System (1) due to direct beam radiation and (2) due to the possible effect of fission products contained in the exhaust gases for various amounts of hydrogen propellant in the tank. Results indicate that the gamma radiation is more significant than the neutron flux. Under different assumptions the gamma contribution from the exhaust gases was 10 to 25 percent of total gamma flux.

Effect of 1.33 Mev gamma radiation and 0.5 Mev electrons on the mechanical properties of graphite fiber composites

NASA Technical Reports Server (NTRS)

Fornes, R. E.; Memory, J. D.; Naranong, N.

1982-01-01

Epoxy/graphite fiber, polyimide/graphite fiber, and polysulfone/graphite fiber composites were exposed to 1.33 Mev gamma irradiation and 0.5 Mev electron bombardment for varying periods of time. The effects of the irradiation treatments on the breaking stress and Young's modulus were studied by a three point bending test. Effects were small; both electron radiation up to 5000 Mrad and gamma radiation up to 350 Mrad resulted in slight increases in both stress and modulus.

Effects of exposing ostrich eggs to doses of gamma radiation on hatchability, growth performance, and some blood biochemicals of hatched chicks.

PubMed

Mahrose, Khalid; Elsayed, Mohammed; Basuony, Hamdy; Gouda, Nour

2016-11-01

Effects of radiating ostrich eggs before incubation on hatchability, growth performance, and some blood components of ostrich chicks were studied. 72 ostrich eggs were randomly distributed into four groups. The first group was kept without exposure to gamma radiation (control). The 2nd, 3rd, and 4th groups were exposed to 0.8, 1.6, and 3.2 Gy, respectively, of 60 Co gamma rays just before incubation. Total bacterial counts (×10 3  CFU) were significantly increased with the increase in gamma radiation levels before incubation. Feed conversion was lower (P ≤ 0.01) in the control group than those irradiated. Embryonic mortality rate (%), hatchability (%) and chick weight at hatch, body weight, daily body weight gain, feed consumption, and all of hematology parameters studied were insignificantly fluctuated with the doses of gamma rays used. Serum concentrations of total protein, albumen, globulin, glucose, and triiodothyronin of the chicks from eggs of the control and the 1st group were significantly the highest. Chicks of the control group had significantly the lowest values of serum concentrations of uric acid, creatinine, triglyceride, total cholesterol, ALT, and AST when compared with the other groups. In conclusion, radiation of ostrich eggs before incubation with a dose of 0.8 Gy gamma has a stimulative effect upon the metabolism of hatched chicks.

Some problems of the detection of the high energy gamma-radiation in space

NASA Astrophysics Data System (ADS)

Fradkin, M. I.; Ginzburg, V. L.; Kurnosova, L. V.; Labensky, A. G.; Razorenov, L. A.; Rusakovich, M. A.; Topchiev, N. P.; Kaplin, V. A.; Runtso, M. F.; Gorchakov, E. V.; Ignatiev, P. P.

1995-05-01

Diffuse gamma radiation in the Galaxy has been measured with instruments onboard the COS-B and Compton Gamma Ray Observatory (CGRO) satellites from the tens of keV up to about 30 GeV. There is no experimental data at higher energies, but this data is very important for the spectrum of primary cosmic rays and the existence of neutralinos (hypothetical supersymmetrical particles which are supposed to constitute dark matter in the Galaxy and create gamma-quanta in the process of annihilation). The GAMMA-400 collaboration is working on the design of a telescope for gamma-ray measurements in the 10-1000 GeV range. The electronics of the GAMMA-400 eliminate some hindering effects, in particular the influence of backscattered gammas emitted by the very massive calorimeter (calorimeter albedo). The GAMMA-400 project may be realized in the near future if economic conditions in Russia are favorable.

Inactivation of murine norovirus-1 in the edible seaweeds Capsosiphon fulvescens and Hizikia fusiforme using gamma radiation.

PubMed

Park, Shin Young; Kang, Sujin; Ha, Sang-Do

2016-06-01

This study investigated the effects of gamma radiation (3-10 kGy) upon the inactivation of murine norovirus-1 (MNV-1), a human norovirus (NoV) surrogate. The edible green and brown algae, fulvescens (Capsosiphon fulvescens) and fusiforme (Hizikia fusiforme), respectively, were experimentally contaminated with 5-6 log10 plaque forming units (PFU)/ml MNV-1. The titer of MNV-1 significantly decreased (P < 0.05) as the dose of gamma radiation increased. MNV-1 titer decreased to 1.16-2.46 log10 PFU/ml in fulvescens and 0.37-2.21 log10 PFU/ml in fusiforme following irradiation. However, all Hunters ('L', 'a' and 'b') and sensory qualities (appearance, color, flavor, texture and overall acceptability) were not significantly (P > 0.05) different in both algae following gamma radiation. The Weibull model was used to generate non-linear survival curves and to calculate Gd values for 1, 2, and 3 log10 reductions of MNV-1 in fulvescens (R(2) = 0.992) and fusiforme (R(2) = 0.988). A Gd value of 1 (90% reduction) corresponded to 2.89 and 3.93 kGy in fulvescens and fusiforme, respectively. A Gd value of 2 (99% reduction) corresponded to 7.75 and 9.02 kGy in fulvescens and fusiforme, respectively, while a Gd value of 3 (99.9% reduction) in fulvescens and fusiforme corresponded with 13.83 and 14.93 kGy of gamma radiation, respectively. A combination of gamma radiation at medium doses and other treatments could be used to inactivate ≥ 3 log10 PFU/ml NoV in seaweed. The inactivation kinetics due to gamma radiation against NoV in these algae might provide basic information for use in seaweed processing and distribution. Copyright © 2015. Published by Elsevier Ltd.

Interaction between cytotoxic effects of gamma-radiation and folate deficiency in relation to choline reserves.

PubMed

Batra, Vipen; Devasagayam, Thomas Paul Asir

2009-01-08

The search for non-toxic radio-protective drugs has yielded many potential agents but most of these compounds have certain amount of toxicity. Recent studies have indicated that bio-molecules such as folate and choline might be of radio-protective value as they are, within broad dose ranges, non-toxic to humans and experimental animals. The objective of the present study was to investigate choline dependent adaptive response to potential synergistic cytotoxic effect of folate deficiency and gamma-radiation. Male Swiss mice maintained on folate sufficient diet (FSD) and folate free diet (FFD) based on AIN-93M formula, were subjected to 1-4Gy total body gamma-irradiation. To investigate liver DNA damage, apurinic/apyrimidinic sites (AP sites) were quantified. A significant increase in liver DNA AP sites with concomitant depletion of liver choline reserves was observed when gamma-radiation was combined with folate deficiency. Further work in this direction suggested that cytotoxic interaction between folate deficiency and gamma radiation might induce utilization of choline and choline containing moieties by modifying levels of key regulatory enzymes dihydrofolate reductase (DHFR) and choline oxidase (ChoOx). Another major finding of these studies is that significant liver damage at higher doses of radiation (3-4Gy), might release considerable amounts of choline reserves to serum. In conclusion, a plausible interpretation of the present studies is that folate deprivation and gamma-radiation interact to mobilize additional choline reserves of hepatic tissue, for redistribution to other organs, which could not be utilized by folate deficiency alone. Present results clearly indicated a distinct choline pool in liver and kidney tissues that could be utilized by folate deficient animals only under radiation stress conditions.

Advanced Development of Gamma-Tocotrienol as a Radiation Countermeasure

DTIC Science & Technology

2017-10-01

injury- specific medicinals and regulatory approval status: part I. Radiation sub- syndromes , animal models and FDA-approved countermeasures. Int J...expression as biomarkers for assessing acute radiation injury. Expert Rev Mol Diagn. 2017 Oct;17(10):871-874. doi: 10.1080/14737159.2017.1366316. Epub...AWARD NUMBER: W81XWH-15-C-0117/ JW140032 TITLE: Advanced development of gamma-tocotrienol as a radiation countermeasure PRINCIPAL INVESTIGATOR

Nuclear radiation analysis

NASA Technical Reports Server (NTRS)

Knies, R. J.; Byrn, N. R.; Smith, H. T.

1972-01-01

A study program of radiation shielding against the deleterious effects of nuclear radiation on man and equipment is reported. The methods used to analyze the radiation environment from bremsstrahlung photons are discussed along with the methods employed by transport code users. The theory and numerical methods used to solve transport of neutrons and gammas are described, and the neutron and cosmic fluxes that would be present on the gamma-ray telescope were analyzed.

Proton and Gamma Radiation Effects in Undoped, Single-doped and co-doped YLiF4 and LuLiF4

NASA Technical Reports Server (NTRS)

Lee, Hyung; Bai, Yingxin; Yu, Kirong; Singh, U.

2009-01-01

Proton and gamma radiation effects in various YLiF4 and LuLiF4 crystals have been investigated. The radiation induced color centers compared with six different kinds of crystal samples in ranges up to 200 krads and 200 MeV. The radiation induced absorption coefficients are strongly dependent on polarization and concentration of rare-earth ions.

ER stress and genomic instability induced by gamma radiation in mice primary cultured glial cells.

PubMed

Chatterjee, Jit; Nairy, Rajesha K; Langhnoja, Jaldeep; Tripathi, Ashutosh; Patil, Rajashekhar K; Pillai, Prakash P; Mustak, Mohammed S

2018-06-01

Ionizing radiation induces various pathophysiological conditions by altering central nervous system (CNS) homeostasis, leading to neurodegenerative diseases. However, the potential effect of ionizing radiation response on cellular physiology in glial cells is unclear. In the present study, micronucleus test, comet assay, and RT-PCR were performed to investigate the potential effect of gamma radiation in cultured oligodendrocytes and astrocytes with respect to genomic instability, Endoplasmic Reticulum (ER) stress, and inflammation. Further, we studied the effect of alteration in ER stress specific gene expression in cortex post whole body radiation in mice. Results showed that exposure of gamma radiation of 2Gy in-vitro cultured astrocytes and oligodendrocytes and 7Gy in-vivo induced ER stress and Inflammation along with profuse DNA damage and Chromosomal abnormality. Additionally, we observed downregulation of myelin basic protein levels in cultured oligodendrocytes exposed to radiation. The present data suggests that ER stress and pro inflammatory cytokines serve as the major players in inducing glial cell dysfunction post gamma irradiation along with induction of genomic instability. Taken together, these results indicate that ER stress, DNA damage, and inflammatory pathways may be critical events leading to glial cell dysfunction and subsequent cell death following exposure to ionizing radiation.

A gamma-ray testing technique for spacecraft. [considering cosmic radiation effects

NASA Technical Reports Server (NTRS)

Gribov, B. S.; Repin, N. N.; Sakovich, V. A.; Sakharov, V. M.

1977-01-01

The simulated cosmic radiation effect on a spacecraft structure is evaluated by gamma ray testing in relation to structural thickness. A drawing of the test set-up is provided and measurement errors are discussed.

Enhanced Biodegradability of Pharmaceuticals and Personal Care Products by Ionizing Radiation.

PubMed

Kim, Hyun Young; Lee, O-Mi; Kim, Tae-Hun; Yu, Seungho

2015-04-01

The radiolytic degradation of antibiotic compounds, including lincomycin (LMC), sulfamethoxazole (SMX), and tetracycline (TCN), and the change of biodegradability of the radiation-treated target compounds were evaluated. As a result, the degradation of target antibiotics by hydrolysis, biodegradation, and gamma irradiation showed a compound-dependent manner. However, the biodegradability of all target compounds was enhanced by the gamma irradiation. The enhanced biodegradability after gamma irradiation (2 kGy) followed the trend of LMC (18.89%)

Real-Time Airborne Gamma-Ray Background Estimation Using NASVD with MLE and Radiation Transport for Calibration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kulisek, Jonathan A.; Schweppe, John E.; Stave, Sean C.

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, we have developed a new technique for real-time estimation ofmore » background gamma radiation from aerial measurements. This method is built upon on the noise-adjusted singular value decomposition (NASVD) technique that was previously developed for estimating the potassium (K), uranium (U), and thorium (T) concentrations in soil post-flight. The method can be calibrated using K, U, and T spectra determined from radiation transport simulations along with basis functions, which may be determined empirically by applying maximum likelihood estimation (MLE) to previously measured airborne gamma-ray spectra. The method was applied to both measured and simulated airborne gamma-ray spectra, with and without man-made radiological source injections. Compared to schemes based on simple averaging, this technique was less sensitive to background contamination from the injected man-made sources and may be particularly useful when the gamma-ray background frequently changes during the course of the flight.« less

Gamma rays induce DNA damage and oxidative stress associated with impaired growth and reproduction in the copepod Tigriopus japonicus.

PubMed

Han, Jeonghoon; Won, Eun-Ji; Lee, Bo-Young; Hwang, Un-Ki; Kim, Il-Chan; Yim, Joung Han; Leung, Kenneth Mei Yee; Lee, Yong Sung; Lee, Jae-Seong

2014-07-01

Nuclear radioisotope accidents are potentially ecologically devastating due to their impact on marine organisms. To examine the effects of exposure of a marine organism to radioisotopes, we irradiated the intertidal copepod Tigriopus japonicus with several doses of gamma radiation and analyzed the effects on mortality, fecundity, and molting by assessing antioxidant enzyme activities and gene expression patterns. No mortality was observed at 96h, even in response to exposure to a high dose (800Gy) of radiation, but mortality rate was significantly increased 120h (5 days) after exposure to 600 or 800Gy gamma ray radiation. We observed a dose-dependent reduction in fecundity of ovigerous females; even the group irradiated with 50Gy showed a significant reduction in fecundity, suggesting that gamma rays are likely to have a population level effect. In addition, we observed growth retardation, particularly at the nauplius stage, in individuals after gamma irradiation. In fact, nauplii irradiated with more than 200Gy, though able to molt to copepodite stage 1, did not develop into adults. Upon gamma radiation, T. japonicus showed a dose-dependent increase in reactive oxygen species (ROS) levels, the activities of several antioxidant enzymes, and expression of double-stranded DNA break damage genes (e.g. DNA-PK, Ku70, Ku80). At a low level (sub-lethal dose) of gamma irradiation, we found dose-dependent upregulation of p53, implying cellular damage in T. japonicus in response to sub-lethal doses of gamma irradiation, suggesting that T. japonicus is not susceptible to sub-lethal doses of gamma irradiation. Additionally, antioxidant genes, phase II enzyme (e.g. GSTs), and cellular chaperone genes (e.g. Hsps) that are involved in cellular defense mechanisms also showed the same expression patterns for sublethal doses of gamma irradiation (50-200Gy). These findings indicate that sublethal doses of gamma radiation can induce oxidative stress-mediated DNA damage and increase the expression of antioxidant enzymes and proteins with chaperone-related functions, thereby significantly affecting life history parameters such as fecundity and molting in the copepod T. japonicus. Copyright © 2014 Elsevier B.V. All rights reserved.

Combination of {gamma}-radiation antagonizes the cytotoxic effects of vincristine and vinblastine on both mitotic arrest and apoptosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sui, Meihua; Fan Weimin

2005-03-15

Purpose: Combination therapy with different modalities is a common practice in the treatment of cancer. The promising clinical profile of vincristine and vinblastine has promoted considerable interest in combining these vinca alkaloids with radiation therapy to treat a variety of solid tumors. However, the therapeutic efficacy and the interaction between the vinca alkaloids with radiation is not entirely clear. In this study, we assessed the potential interactions in the combination of vincristine or vinblastine with {gamma}-radiation against human tumor cells in vitro. Methods and materials: Vincristine or vinblastine and {gamma}-radiation were administrated at three different sequences designed as preradiated, coradiated,more » and postradiated combinations in human breast cancer cells and human epidermoid carcinoma cells. The cytotoxic interactions and mutual influences between these two modalities were analyzed by a series of assays including cytotoxic, morphologic, and biochemical examinations. Results: Our results showed that the combination of these two modalities did not produce any synergistic or additive effects. Instead, the clonogenic assays showed the survival rates of these combinations were increased up to 2.17-fold and 2.7-fold, respectively, of those treated with vincristine or vinblastine alone (p < 0.01). DNA fragmentation, T{alpha}T-mediated dUTP nick end labeling (TUNEL) assay, and flow cytometric assays also showed that the combination of {gamma}-radiation significantly interfered with the ability of these vinca alkaloids to induce apoptosis. Further analyses indicated that addition of {gamma}-radiation resulted in cell cycle arrest at the G{sub 2} phase, which subsequently prevented the mitotic arrest induced by vincristine or vinblastine. In addition, biochemical examinations revealed that {gamma}-radiation regulated p34{sup cdc2}/cyclin B1 and survivin, and inhibited I{kappa}B{alpha} degradation and bcl-2 phosphorylation. Conclusions: These results suggest that {gamma}-radiation might specifically block the cell cycle at the G{sub 2} phase, which in turn interferes with the cytotoxic effects of vincristine or vinblastine on mitotic arrest and apoptosis. Thereby, it eventually results in an antagonistic interaction between these two modalities. This finding may be implicated in the clinical application of combination therapy of vinca alkaloids and radiation.« less

Impact evaluation of α-lipoic acid in gamma-irradiated erythrocytes

NASA Astrophysics Data System (ADS)

Desouky, Omar S.; Selim, Nabila S.; Elbakrawy, Eman M.; Rezk, Rezk A.

2011-03-01

This work is intended to study in vitro the ability of lipoic acid to protect erythrocytes against the oxidative damage resulting from exposure to gamma radiation through measurement of their rheological properties and to study the effects of detergent on their membrane solubility and permeability. Different doses of gamma radiation were applied: the most recommended and applied dose (25 Gy), and two higher doses, namely 50 and 100 Gy. The effect of addition of lipoic acid as well as its effect as a radioprotector was tested. The obtained results show changes in structural integrity of the erythrocyte cell membrane components as a result of oxidative damage due to gamma radiation that could be improved by pre-treatment with the antioxidant lipoic acid.

Evaluation of the gamma radiation shielding parameters of bismuth modified quaternary glass system

NASA Astrophysics Data System (ADS)

Kaur, Parminder; Singh, K. J.; Thakur, Sonika

2018-05-01

Glasses modified with heavy metal oxides (HMO) are an interesting area of research in the field of gamma-ray shielding. Bismuth modified lithium-zinc-borate glasses have been studied whereby bismuth oxide is added from 0 to 50 mol%. The gamma ray shielding properties of the glasses were evaluated at photon energy 662 keV with the help of XMuDat computer program by using the Hubbell and Seltzer database. Various gamma ray shielding parameters such as attenuation coefficient, shield thickness in terms of half and tenth value layer, effective atomic number have been studied in this work. A useful comparison of this glass system has been made with standard radiation shielding concretes viz. ordinary, barite and iron concrete. The glass samples containing 20 to 50 mol% bismuth oxide have shown better gamma ray shielding properties and hence have the potential to become good radiation absorbers.

Measurement of angularly dependent spectra of betatron gamma-rays from a laser plasma accelerator with quadrant-sectored range filters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeon, Jong Ho, E-mail: jhjeon07@ibs.re.kr; Nakajima, Kazuhisa, E-mail: naka115@dia-net.ne.jp; Rhee, Yong Joo

Measurement of angularly dependent spectra of betatron gamma-rays radiated by GeV electron beams from laser wakefield accelerators (LWFAs) are presented. The angle-resolved spectrum of betatron radiation was deconvolved from the position dependent data measured for a single laser shot with a broadband gamma-ray spectrometer comprising four-quadrant sectored range filters and an unfolding algorithm, based on the Monte Carlo code GEANT4. The unfolded gamma-ray spectra in the photon energy range of 0.1–10 MeV revealed an approximately isotropic angular dependence of the peak photon energy and photon energy-integrated fluence. As expected by the analysis of betatron radiation from LWFAs, the results indicate thatmore » unpolarized gamma-rays are emitted by electrons undergoing betatron motion in isotropically distributed orbit planes.« less

Effect of gamma irradiation on antinutritional factors in broad bean

NASA Astrophysics Data System (ADS)

Al-Kaisey, Mahdi T.; Alwan, Abdul-Kader H.; Mohammad, Manal H.; Saeed, Amjed H.

2003-06-01

The effect of gamma irradiation on the level of antinutritional factors (trypsin inhibitor (TI), phytic acid and oligosaccharides) of broad bean was investigated. The seeds were subjected to gamma irradiation at 0, 2.5, 5, 7.5 and 10 kGy, respectively using cobalt-60 gamma radiation with a dose rate 2.37 kGy/h. TI activity was reduced by 4.5%, 6.7%, 8.5% and 9.2% at 2.5, 5, 7.5 and 10 kGy, respectively. Meanwhile, irradiation at 10.2, 12.3, 15.4 and 18.2 kGy reduced the phytic acid content. The flatulence causing oligosaccharides were decreased as the radiation dose increased. The chemical composition (protein, oil, ash and total carbohydrates) of the tested seeds was determined. Gamma radiation seems to be a good procedure to improve the quality of broad bean from the nutritional point of view.

Radiation Characterization Summary: ACRR Polyethylene-Lead-Graphite (PLG) Bucket Located in the Central Cavity on the 32-Inch Pedestal at the Core Centerline (ACRR-PLG-CC-32-cl).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parma, Edward J.,; Vehar, David W.; Lippert, Lance L.

2015-06-01

This document presents the facility-recommended characterization of the neutron, prompt gamma-ray, and delayed gamma-ray radiation fields in the Annular Core Research Reactor (ACRR) for the polyethylene-lead-graphite (PLG) bucket in the central cavity on the 32-inch pedestal at the core centerline. The designation for this environment is ACRR-PLG-CC-32-cl. The neutron, prompt gamma-ray, and delayed gamma-ray energy spectra, uncertainties, and covariance matrices are presented as well as radial and axial neutron and gamma-ray fluence profiles within the experiment area of the bucket. Recommended constants are given to facilitate the conversion of various dosimetry readings into radiation metrics desired by experimenters. Representative pulsemore » operations are presented with conversion examples. Acknowledgements The authors wish to thank the Annular Core Research Reactor staff and the Radiation Metrology Laboratory staff for their support of this work. Also thanks to David Ames for his assistance in running MCNP on the Sandia parallel machines.« less

Development of a digital method for neutron/gamma-ray discrimination based on matched filtering

NASA Astrophysics Data System (ADS)

Korolczuk, S.; Linczuk, M.; Romaniuk, R.; Zychor, I.

2016-09-01

Neutron/gamma-ray discrimination is crucial for measurements with detectors sensitive to both neutron and gamma-ray radiation. Different techniques to discriminate between neutrons and gamma-rays based on pulse shape analysis are widely used in many applications, e.g., homeland security, radiation dosimetry, environmental monitoring, fusion experiments, nuclear spectroscopy. A common requirement is to improve a radiation detection level with a high detection reliability. Modern electronic components, such as high speed analog to digital converters and powerful programmable digital circuits for signal processing, allow us to develop a fully digital measurement system. With this solution it is possible to optimize digital signal processing algorithms without changing any electronic components in an acquisition signal path. We report on results obtained with a digital acquisition system DNG@NCBJ designed at the National Centre for Nuclear Research. A 2'' × 2'' EJ309 liquid scintillator was used to register mixed neutron and gamma-ray radiation from PuBe sources. A dedicated algorithm for pulse shape discrimination, based on real-time filtering, was developed and implemented in hardware.

Radiation Characterization Summary: ACRR Central Cavity Free-Field Environment with the 32-Inch Pedestal at the Core Centerline (ACRR-FF-CC-32-cl).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vega, Richard Manuel; Parma, Edward J.; Naranjo, Gerald E.

2015-08-01

This document presents the facilit y - recommended characteri zation o f the neutron, prompt gamma - ray, and delayed gamma - ray radiation fields in the Annular Core Research Reactor ( ACRR ) for the cen tral cavity free - field environment with the 32 - inch pedestal at the core centerline. The designation for this environmen t is ACRR - FF - CC - 32 - cl. The neutron, prompt gamma - ray , and delayed gamma - ray energy spectra , uncertainties, and covariance matrices are presented as well as radial and axial neutron and gamma -more » ray fluence profiles within the experiment area of the cavity . Recommended constants are given to facilitate the conversion of various dosimetry readings into radiation metrics desired by experimenters. Representative pulse operations are presented with conversion examples . Acknowledgements The authors wish to th ank the Annular Core Research Reactor staff and the Radiation Metrology Laboratory staff for their support of this work . Also thanks to David Ames for his assistance in running MCNP on the Sandia parallel machines.« less

Effect of electron beam and gamma radiation on drug-susceptible and drug-resitant listeria monocytogenes strains in salmon under different temperature.

PubMed

Skowron, Krzysztof; Grudlewska, Katarzyna; Gryń, Grzegorz; Skowron, Karolina Jadwiga; Świeca, Agnieszka; Paluszak, Zbigniew; Zimek, Zbigniew; Rafalski, Andrzej; Gospodarek-Komkowska, Eugenia

2018-05-04

To investigate the effect of gamma radiation and high energy electron beam doses on the inactivation of antibiotic-susceptible and antibiotic-resistant Listeria monocytogenes strains inoculated on the surface of raw salmon fillets stored at different temperature (-20°C, 4°C and 25°C). The population of bacteria strains resistance to penicillin, ampicillin, meropenem, erythromycin and trimethoprim-sulfamethoxazole was generated. When using gamma irradiation, the theoretical lethal dose ranged from 1.44 to 5.68 kGy and for electron beam the values ranged from 2.99 to 6.83 kGy. The theoretical lethal dose for both radiation methods was higher for antibiotic-resistant strains. Gamma radiation proved to be a more effective method for extending salmon fillet shelf-life. The evaluation of PFGE electrophoregram revealed that the repair of radiation-caused DNA damage occurred faster in antibiotic-resistant L. monocytogenes strains. The number of live L. monocytogenes cells, 40 hours after irradiation, also was higher in antibiotic-resistant strain suspension. The present study showed that gamma radiation was more effective in the elimination of the tested microorganisms and food preservation, than a high energy electron beam. The antibiotic-resistant L. monocytogenes strains were more resistant to both radiation methods. There are a lot of research on the effect of radiation on the number of bacteria in food products. However, there is almost no information about the effect of strain properties, such as drug susceptibility, virulence, etc., on their resistance to ionizing radiation. An increasing number of drug resistant bacterial strains isolated from food, encourages to take up this research subject. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Simultaneous beta and gamma spectroscopy

DOEpatents

Farsoni, Abdollah T.; Hamby, David M.

2010-03-23

A phoswich radiation detector for simultaneous spectroscopy of beta rays and gamma rays includes three scintillators with different decay time characteristics. Two of the three scintillators are used for beta detection and the third scintillator is used for gamma detection. A pulse induced by an interaction of radiation with the detector is digitally analyzed to classify the type of event as beta, gamma, or unknown. A pulse is classified as a beta event if the pulse originated from just the first scintillator alone or from just the first and the second scintillator. A pulse from just the third scintillator is recorded as gamma event. Other pulses are rejected as unknown events.

Reusable shielding material for neutron- and gamma-radiation

NASA Astrophysics Data System (ADS)

Calzada, Elbio; Grünauer, Florian; Schillinger, Burkhard; Türck, Harald

2011-09-01

At neutron research facilities all around the world radiation shieldings are applied to reduce the background of neutron and gamma radiation as far as possible in order to perform high quality measurements and to fulfill the radiation protection requirements. The current approach with cement-based compounds has a number of shortcomings: "Heavy concrete" contains a high amount of elements, which are not desired to obtain a high attenuation of neutron and/or gamma radiation (e.g. calcium, carbon, oxygen, silicon and aluminum). A shielding material with a high density of desired nuclei such as iron, hydrogen and boron was developed for the redesign of the neutron radiography facility ANTARES at beam tube 4 (located at a cold neutron source) of FRM-II. The composition of the material was optimized by help of the Monte Carlo code MCNP5. With this shielding material a considerable higher attenuation of background radiation can be obtained compared to usual heavy concretes.

Gamma Ray Pulsars: Multiwavelength Observations

NASA Technical Reports Server (NTRS)

Thompson, David J.

2004-01-01

High-energy gamma rays are a valuable tool for studying particle acceleration and radiation in the magnetospheres of energetic pulsars. The seven or more pulsars seen by instruments on the Compton Gamma Ray Observatory (CGRO) show that: the light curves usually have double-peak structures (suggesting a broad cone of emission); gamma rays are frequently the dominant component of the radiated power; and all the spectra show evidence of a high-energy turnover. For all the known gamma-ray pulsars, multiwavelength observations and theoretical models based on such observations offer the prospect of gaining a broad understanding of these rotating neutron stars. The Gamma-ray Large Area Space Telescope (GLAST), now in planning for a launch in 2006, will provide a major advance in sensitivity, energy range, and sky coverage.

Adult myeloid leukaemia, geology, and domestic exposure to radon and gamma radiation: a case control study in central Italy.

PubMed

Forastiere, F; Sperati, A; Cherubini, G; Miceli, M; Biggeri, A; Axelson, O

1998-02-01

To investigate whether indoor randon or gamma radiation might play a part in myeloid leukaemia as suggested by studies based on crude geographical or geological data for exposure assessment. For six months randon and gamma radiation was measured with solid state nuclear track detectors and thermoluminescent dosimeters in dwellings of 44 adult male cases of acute myeloid leukaemia and 211 controls (all subjects deceased). Conditional logistic regression ORs (ORs) and 95% confidence intervals (95% CIs) were estimated for quartiles of radon and gamma radiation and for municipality and dwelling characteristics. The risk of leukaemia was associated with an increasing urbanisation index (p value for trend = 0.008). An increased OR was found among those living in more modern houses (OR 3.0, 95% CI 1.4 to 6.6). Confirming the findings of a previous study in the same area, geological features bore a positive association with myeloid leukemia, even by adjusting for level of urbanisation. Contrary to expectations from the previous study, however, no association appeared between myeloid leukaemia and radon and gamma radiation; for the highest quartiles of exposure, ORs were 0.56 (95% CI 0.2 to 1.4) and 0.52 (95% CI 0.2 to 1.4), respectively. Considering only subjects who had lived > or = 20 years in the monitored home and adjusting for urbanisation, there was still no effect of exposure to radiation. In view of the limited numbers, the results do not in general refute a possible risk of myeloid leukaemia from exposure to indoor radon or gamma radiation, but decrease the credibility of such a relation in the area studied and also of other studies suggesting an effect without monitoring indoor radiation. Some other fairly strong determinants have appeared--that is, level of urbanisation and living in modern houses--that might need further consideration.

Adult myeloid leukaemia, geology, and domestic exposure to radon and gamma radiation: a case control study in central Italy

PubMed Central

Forastiere, F.; Sperati, A.; Cherubini, G.; Miceli, M.; Biggeri, A.; Axelson, O.

1998-01-01

OBJECTIVES: To investigate whether indoor randon or gamma radiation might play a part in myeloid leukaemia as suggested by studies based on crude geographical or geological data for exposure assessment. METHODS: For six months randon and gamma radiation was measured with solid state nuclear track detectors and thermoluminescent dosimeters in dwellings of 44 adult male cases of acute myeloid leukaemia and 211 controls (all subjects deceased). Conditional logistic regression ORs (ORs) and 95% confidence intervals (95% CIs) were estimated for quartiles of radon and gamma radiation and for municipality and dwelling characteristics. RESULTS: The risk of leukaemia was associated with an increasing urbanisation index (p value for trend = 0.008). An increased OR was found among those living in more modern houses (OR 3.0, 95% CI 1.4 to 6.6). Confirming the findings of a previous study in the same area, geological features bore a positive association with myeloid leukemia, even by adjusting for level of urbanisation. Contrary to expectations from the previous study, however, no association appeared between myeloid leukaemia and radon and gamma radiation; for the highest quartiles of exposure, ORs were 0.56 (95% CI 0.2 to 1.4) and 0.52 (95% CI 0.2 to 1.4), respectively. Considering only subjects who had lived > or = 20 years in the monitored home and adjusting for urbanisation, there was still no effect of exposure to radiation. CONCLUSIONS: In view of the limited numbers, the results do not in general refute a possible risk of myeloid leukaemia from exposure to indoor radon or gamma radiation, but decrease the credibility of such a relation in the area studied and also of other studies suggesting an effect without monitoring indoor radiation. Some other fairly strong determinants have appeared--that is, level of urbanisation and living in modern houses-- that might need further consideration.   PMID:9614394

Mechanism of action for anti-radiation vaccine in reducing the biological impact of high-dose gamma irradiation

NASA Astrophysics Data System (ADS)

Maliev, Vladislav; Popov, Dmitri; Jones, Jeffrey A.; Casey, Rachael C.

Ionizing radiation is a major health risk of long-term space travel, the biological consequences of which include genetic and oxidative damage. In this study, we propose an original mechanism by which high doses of ionizing radiation induce acute toxicity. We identified biological components that appear in the lymphatic vessels shortly after high-dose gamma irradiation. These radiation-induced toxins, which we have named specific radiation determinants (SRD), were generated in the irradiated tissues and then circulated throughout the body via the lymph circulation and bloodstream. Depending on the type of SRD elicited, different syndromes of acute radiation sickness (ARS) were expressed. The SRDs were developed into a vaccine used to confer active immunity against acute radiation toxicity in immunologically naïve animals. Animals that were pretreated with SRDs exhibited resistance to lethal doses of gamma radiation, as measured by increased survival times and survival rates. In comparison, untreated animals that were exposed to similar large doses of gamma radiation developed acute radiation sickness and died within days. This phenomenon was observed in a number of mammalian species. Initial analysis of the biochemical characteristics indicated that the SRDs were large molecular weight (200-250 kDa) molecules that were comprised of a mixture of protein, lipid, carbohydrate, and mineral. Further analysis is required to further identify the SRD molecules and the biological mechanism by which they mediate the toxicity associated with acute radiation sickness. By doing so, we may develop an effective specific immunoprophylaxis as a countermeasure against the acute effects of ionizing radiation.

Mechanism of Action for Anti-radiation Vaccine in Reducing the Biological Impact of High-dose Gamma Irradiation

NASA Technical Reports Server (NTRS)

Maliev, Vladislav; Popov, Dmitri; Jones, Jeffrey A.; Casey, Rachael C.

2007-01-01

Ionizing radiation is a major health risk of long-term space travel, the biological consequences of which include genetic and oxidative damage. In this study, we propose an original mechanism by which high doses of ionizing radiation induce acute toxicity. We identified biological components that appear in the lymphatic vessels shortly after gamma irradiation. These radiation-induced toxins, which we have named specific radiation determinants (SRD), were generated in the irradiated tissues and then collected and circulated throughout the body via the lymph circulation and bloodstream. Depending on the type of SRD elicited, different syndromes of acute radiation sickness (ARS) were expressed. The SRDs were developed into a vaccine used to confer active immunity against acute radiation toxicity in immunologically naive animals. Animals that were pretreated with SRDs exhibited resistance to lethal doses of gamma radiation, as measured by increased survival times and survival rates. In comparison, untreated animals that were exposed to similar large doses of gamma radiation developed acute radiation sickness and died within days. This phenomenon was observed in a number of mammalian species. Initial analysis of the biochemical characteristics indicated that the SRDs were large molecular weight (200-250 kDa) molecules that were comprised of a mixture of protein, lipid, carbohydrate, and mineral. Further analysis is required to further identify the SRD molecules and the biological mechanism by which the mediate the toxicity associated with acute radiation sickness. By doing so, we may develop an effective specific immunoprophylaxis as a countermeasure against the acute effects of ionizing radiation.

Inactivation of rabies diagnostic reagents by gamma radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gamble, W.C.; Chappell, W.A.; George, E.H.

1980-11-01

Treatment of CVS-11 rabies adsorbing suspensions and street rabies infected mouse brains with gamma radiation resulted in inactivated reagents that are safer to distribute and use. These irradiated reagents were as sensitive and reactive as the nonirradiated control reagents.

EFFECTS OF GAMMA RADIATION ON TWO DECAPOD CRUSTACEANS, PALAEMONETES PUGIO AND UCA PUGNAX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rees, G.H.

1962-03-01

Experiments are described that were undertaken with the objective of determining the lethal dosages of gamma radiation, particularly the doses at which 50% succumb (LD/sub 50/), for 2 decapod crustaceans. (Pub. Health Eng. Abstr.)

Environmental radiology assessment in Lahad Datu, Sabah

NASA Astrophysics Data System (ADS)

Siti Fharhana, Yusof; Wan Muhamad Saridan, Wan Hassan; Ahmad Termizi, Ramli; Mohd Hilmi, Sahini; Mohammad Syazwan, Mohd Sanusi; Nor Afifah, Basri; Nor Zati Hani, Abu Hanifah

2017-10-01

Monitoring terrestial gamma radiation is crucial to prepare a baseline data for environmental radiological protection. Radiological research was carried out in Lahad Datu, Sabah to obtain the radioactivity status and terrestrial gamma radiation level in the area. We measure the terrestrial gamma radiation dose rates and analyse the radioactivity concentration of primordial radionuclides for radiological risk assessment. We identified that the annual estimation of dose effective for public is below the public dose limit, 1 mSv per year. Public and environment safety and health are remain secure. The obtained data and results can be used as reference for environmental radiology protection.

Inactivation of aflatoxin B1 by using the synergistic effect of hydrogen peroxide and gamma radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patel, U.D.; Govindarajan, P.; Dave, P.J.

Inactivation of aflatoxin B1 was studied by using gamma radiation and hydrogen peroxide. A 100-krad dose of gamma radiation was sufficient to inactivate 50 micrograms of aflatoxin B1 in the presence of 5% hydrogen peroxide, and 400 krad was required for total degradation of 100 micrograms of aflatoxin in the same system. Degradation of aflatoxin B1 was confirmed by high-pressure liquid chromatographic and thin-layer chromatographic analysis. Ames microsomal mutagenicity test showed loss of aflatoxin activity. This method of detoxification also reduces the toxin levels effectively in artificially contaminated groundnuts.

The combined effect of uranium and gamma radiation on biological responses and oxidative stress induced in Arabidopsis thaliana.

PubMed

Vanhoudt, Nathalie; Vandenhove, Hildegarde; Horemans, Nele; Wannijn, Jean; Van Hees, May; Vangronsveld, Jaco; Cuypers, Ann

2010-11-01

Uranium never occurs as a single pollutant in the environment, but always in combination with other stressors such as ionizing radiation. As effects induced by multiple contaminants can differ markedly from the effects induced by the individual stressors, this multiple pollution context should not be neglected. In this study, effects on growth, nutrient uptake and oxidative stress induced by the single stressors uranium and gamma radiation are compared with the effects induced by the combination of both stressors. By doing this, we aim to better understand the effects induced by the combined stressors but also to get more insight in stressor-specific response mechanisms. Eighteen-day-old Arabidopsis thaliana seedlings were exposed for 3 days to 10 muM uranium and 3.5 Gy gamma radiation. Gamma radiation interfered with uranium uptake, resulting in decreased uranium concentrations in the roots, but with higher transport to the leaves. This resulted in a better root growth but increased leaf lipid peroxidation. For the other endpoints studied, effects under combined exposure were mostly determined by uranium presence and only limited influenced by gamma presence. Furthermore, an important role is suggested for CAT1/2/3 gene expression under uranium and mixed stressor conditions in the leaves.

Radiation dose in the high background radiation area in Kerala, India.

PubMed

Christa, E P; Jojo, P J; Vaidyan, V K; Anilkumar, S; Eappen, K P

2012-03-01

A systematic radiological survey has been carried out in the region of high-background radiation area in Kollam district of Kerala to define the natural gamma-radiation levels. One hundred and forty seven soil samples from high-background radiation areas and five samples from normal background region were collected as per standard sampling procedures and were analysed for (238)U, (232)Th and (40)K by gamma-ray spectroscopy. External gamma dose rates at all sampling locations were also measured using a survey meter. The activities of (238)U, (232)Th and (40)K was found to vary from 17 to 3081 Bq kg(-1), 54 to 11976 Bq kg(-1) and BDL (67.4 Bq kg(-1)) to 216 Bq kg(-1), respectively, in the study area. Such heterogeneous distribution of radionuclides in the region may be attributed to the deposition phenomenon of beach sand soil in the region. Radium equivalent activities were found high in several locations. External gamma dose rates estimated from the levels of radionuclides in soil had a range from 49 to 9244 nGy h(-1). The result of gamma dose rate measured at the sampling sites using survey meter showed an excellent correlation with dose rates computed from the natural radionuclides estimated from the soil samples.

Gamma radiation induced oxidation and tocopherols decrease in in-shell, peeled and blanched peanuts.

PubMed

de Camargo, Adriano Costa; de Souza Vieira, Thais Maria Ferreira; Regitano-D'Arce, Marisa Aparecida Bismara; de Alencar, Severino Matias; Calori-Domingues, Maria Antonia; Canniatti-Brazaca, Solange Guidolin

2012-01-01

In-shell, peeled and blanched peanut samples were characterized in relation to proximate composition and fatty acid profile. No difference was found in relation to its proximate composition. The three major fatty acids were palmitic acid, oleic acid, and linoleic acid. In order to investigate irradiation and storage effects, peanut samples were submitted to doses of 0.0, 5.0, 7.5 or 10.0 kGy, stored for six months at room temperature and monitored every three months. Peanuts responded differently to irradiation, particularly with regards to tocopherol contents, primary and secondary oxidation products and oil stability index. Induction periods and tocopherol contents were negatively correlated with irradiation doses and decreased moderately during storage. α-Tocopherol was the most gamma radiation sensitive and peeled samples were the most affected. A positive correlation was found among tocopherol contents and the induction period of the oils extracted from irradiated samples. Gamma radiation and storage time increased oxidation compounds production. If gamma radiation is considered an alternative for industrial scale peanut conservation, in-shell samples are the best feedstock. For the best of our knowledge this is the first article with such results; this way it may be helpful as basis for future studies on gamma radiation of in-shell crops.

Gamma Radiation Induced Oxidation and Tocopherols Decrease in In-Shell, Peeled and Blanched Peanuts

PubMed Central

de Camargo, Adriano Costa; de Souza Vieira, Thais Maria Ferreira; Regitano-D’Arce, Marisa Aparecida Bismara; de Alencar, Severino Matias; Calori-Domingues, Maria Antonia; Canniatti-Brazaca, Solange Guidolin

2012-01-01

In-shell, peeled and blanched peanut samples were characterized in relation to proximate composition and fatty acid profile. No difference was found in relation to its proximate composition. The three major fatty acids were palmitic acid, oleic acid, and linoleic acid. In order to investigate irradiation and storage effects, peanut samples were submitted to doses of 0.0, 5.0, 7.5 or 10.0 kGy, stored for six months at room temperature and monitored every three months. Peanuts responded differently to irradiation, particularly with regards to tocopherol contents, primary and secondary oxidation products and oil stability index. Induction periods and tocopherol contents were negatively correlated with irradiation doses and decreased moderately during storage. α-Tocopherol was the most gamma radiation sensitive and peeled samples were the most affected. A positive correlation was found among tocopherol contents and the induction period of the oils extracted from irradiated samples. Gamma radiation and storage time increased oxidation compounds production. If gamma radiation is considered an alternative for industrial scale peanut conservation, in-shell samples are the best feedstock. For the best of our knowledge this is the first article with such results; this way it may be helpful as basis for future studies on gamma radiation of in-shell crops. PMID:22489128

Space-Borne Observations of Intense Gamma-Ray Flashes (TGFs) Above Thunderstorms

NASA Technical Reports Server (NTRS)

Fishman, Gerald J.

2010-01-01

Intense millisecond flashes of MeV photons are being observed with space-borne detectors. These terrestrial gamma-ray flashes (TGFs) were discovered with the Burst and Transient Source Experiment (BATSE) aboard the Compton Gamma-Ray Observatory (CGRO) in the early 1990s. They are now being observed with several other instruments, including the Gamma-ray Burst Monitor (GBM) detectors on the Fermi Gamma-ray Space Telescope. Although Fermi-GBM was designed and optimized for the observation of cosmic gamma-ray bursts (GRBs), it has unprecedented capabilities for TGF observations. The TGFs usually have extremely hard continuous spectra, typical of highly-Comptonized bremsstrahlung radiation. These spectral are harder than those of GRBs, with photons extending to over 40 MeV. The most likely origin of these high-energy photons is bremsstrahlung radiation produced by a relativistic runaway avalanche electron beam. Such a beam is expected to be produced in an extended, intense electric field in or above thunderstorm regions. The altitude of origin and beaming characteristics of the radiation are quite uncertain. These TGFs may produce an appreciable radiation dose to passengers and crew in nearby aircraft. They have generated considerable observational and theoretical interest in recent years. Instruments are being designed specifically for TGF observations from new spacecraft as well as from airborne platforms.

Real-time airborne gamma-ray background estimation using NASVD with MLE and radiation transport for calibration

NASA Astrophysics Data System (ADS)

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.

Low-dose radiation modifies skin response to acute gamma-rays and protons.

PubMed

Mao, Xiao Wen; Pecaut, Michael J; Cao, Jeffrey D; Moldovan, Maria; Gridley, Daila S

2013-01-01

The goal of the present study was to obtain pilot data on the effects of protracted low-dose/low-dose-rate (LDR) γ-rays on the skin, both with and without acute gamma or proton irradiation (IR). Six groups of C57BL/6 mice were examined: a) 0 Gy control, b) LDR, c) Gamma, d) LDR+Gamma, e) Proton, and f) LDR+Proton. LDR radiation was delivered to a total dose of 0.01 Gy (0.03 cGy/h), whereas the Gamma and Proton groups received 2 Gy (0.9 Gy/min and 1.0 Gy/min, respectively). Assays were performed 56 days after exposure. Skin samples from all irradiated groups had activated caspase-3, indicative of apoptosis. The significant (p<0.05) increases in immunoreactivity in the Gamma and Proton groups were not present when LDR pre-exposure was included. However, the terminal deoxynucleotidyl transferase dUTP nick-end labeling assay for DNA fragmentation and histological examination of hematoxylin and eosin-stained sections revealed no significant differences among groups, regardless of radiation regimen. The data demonstrate that caspase-3 activation initially triggered by both forms of acute radiation was greatly elevated in the skin nearly two months after whole-body exposure. In addition, LDR γ-ray priming ameliorated this response.

RADIATION INJURY OF MYELOPOIESIS IN MONKEYS,

DTIC Science & Technology

RADIATION EFFECTS, *HEMATOPOIETIC SYSTEM, RADIATION INJURIES, GAMMA RAYS, LEUKOCYTES, BLOOD COUNTS, HEMOGLOBIN, MORTALITY RATE, BONE MARROW, LEUKEMIA, ANEMIAS , RADIATION SICKNESS, RADIATION DOSAGE, USSR.

Radiation dosimetry on revegetated uranium mill tailings in western South Dakota

Treesearch

Mark A. Rumble

1986-01-01

Measurement of gamma radiation using thermoluminescent dosimeters on three uranium mill tailings areas and a control area showed exposure rates below ground depended on the amount and type of soil covering. Covering tailings with 30 cm of shale and 60 cm of topsoil reduced gamma radiation exposure belowground to rates similar to the control area. Soil covering of 30 cm...

Increase of radiation resistance of a soil microflora exposed to long-term gamma irradiation. [/sup 60/Co

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eriksen, W.H.; Emborg, C.

1978-10-01

Soil microflora were exposed to long-term (18 months) gamma irradiation in an open-air facility at three different doses, 15, 150, and 1500 krads/18 months. The radiation resistance increased at all doses when compared with the radiation resistance of the microflora from soil shielded from the irradiation with a lead wall.

Observations of Galactic gamma-radiation with the SMM spectrometer

NASA Technical Reports Server (NTRS)

Share, G. H.; Kinzer, R. L.; Messina, D. C.; Purcell, W. R.; Chupp, E. L.

1986-01-01

Preliminary results from the SMM gamma-ray spectrometer are reported which indicate the detection of a constant source of 0.511-MeV annihilation radiation from the Galaxy. Year-to-year variability appears to be less than 30 percent. The radiation probably comes from a diffuse source and is not associated with the reported compact object at the Galactic center.

Response of oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), eggs to gamma radiation

NASA Astrophysics Data System (ADS)

Silva, W. D.; Arthur, V.; Mastrangelo, T.

2010-10-01

As insects increase in radiotolerance as they develop and usually several developmental stages of the pest may be present in the fresh shipped commodity, it is important to know the radiation susceptibility of the stages of the target insect before the establishment of ionizing radiation quarantine treatments. This study was performed to determine the radiotolerance of eggs of the oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), to gamma radiation. This species is considered as one of the most serious worldwide pests for temperate fruits, especially peaches. Eggs (12 h old) were exposed to 0 (control), 25, 35, 50, 75, 100, 125 and 150 Gy of gamma radiation. Surviving larvae were allowed to feed on an artificial diet. Three days after irradiation, it was verified that larvae's cephalic capsules were significantly affected by gamma radiation, and the estimated mean LD 90 and LD 99 were 66.3 Gy and 125.8 Gy, respectively. Oriental fruit moth eggs revealed to be quite radiosensitive and very low doses as 50 Gy were sufficient to disrupt G. molesta embryogenesis. At 25 Gy, only male adults originated from the surviving larvae and, after mating with untreated fertile females, shown to be sterile.

Radiation anomaly detection algorithms for field-acquired gamma energy spectra

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Sanjoy; Maurer, Richard; Wolff, Ron; Guss, Paul; Mitchell, Stephen

2015-08-01

The Remote Sensing Laboratory (RSL) is developing a tactical, networked radiation detection system that will be agile, reconfigurable, and capable of rapid threat assessment with high degree of fidelity and certainty. Our design is driven by the needs of users such as law enforcement personnel who must make decisions by evaluating threat signatures in urban settings. The most efficient tool available to identify the nature of the threat object is real-time gamma spectroscopic analysis, as it is fast and has a very low probability of producing false positive alarm conditions. Urban radiological searches are inherently challenged by the rapid and large spatial variation of background gamma radiation, the presence of benign radioactive materials in terms of the normally occurring radioactive materials (NORM), and shielded and/or masked threat sources. Multiple spectral anomaly detection algorithms have been developed by national laboratories and commercial vendors. For example, the Gamma Detector Response and Analysis Software (GADRAS) a one-dimensional deterministic radiation transport software capable of calculating gamma ray spectra using physics-based detector response functions was developed at Sandia National Laboratories. The nuisance-rejection spectral comparison ratio anomaly detection algorithm (or NSCRAD), developed at Pacific Northwest National Laboratory, uses spectral comparison ratios to detect deviation from benign medical and NORM radiation source and can work in spite of strong presence of NORM and or medical sources. RSL has developed its own wavelet-based gamma energy spectral anomaly detection algorithm called WAVRAD. Test results and relative merits of these different algorithms will be discussed and demonstrated.

NMR-based Metabolomics Analysis of Liver from C57BL/6 Mouse Exposed to Ionizing Radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Xiongjie; Hu, Mary; Zhang, Xu

The health effects of exposing to ionizing radiation are attracting great interest in the space exploration community and patients considering radiotherapy. However, the impact to metabolism after exposure to high dose radiation has not yet been clearly defined in livers. In the present study, 1H nuclear magnetic resonance (NMR) based metabolomics combined with multivariate data analysis are applied to study the changes of metabolism in the liver of C57BL/6 mouse after whole body exposure to either gamma (3.0 and 7.8 Gy) or proton (3.0 Gy) radiation. Principal component analysis (PCA) and orthogonal projection to latent structures analysis (OPLS) are employedmore » for classification and identification of potential biomarkers associated with gamma and proton irradiation. The results show that the radiation exposed groups can be well separated from the control group. At the same radiation dosage, the group exposed to proton radiation is well separated from the group exposed to gamma radiation, indicating different radiation sources induce different alterations based on metabolic profiling. Common to both gamma and proton radiation at the high radiation doses studied in this work, compared with the control groups the concentrations of choline, O-phosphocholine and trimethylamine N-oxide are decreased statistically, while those of glutamine, glutathione, malate, creatinine, phosphate, betaine and 4-hydroxyphenylacetate are statistically and significantly elevated after exposure to radiation. Since these altered metabolites are associated with multiple biological pathways, the changes suggest that the exposure to radiation induce abnormality in multiple biological pathways. In particular, metabolites such as 4-hydroxyphenylacetate, betaine, glutamine, choline and trimethylamine N-oxide may be good candidates of pre-diagnose biomarkers for ionizing radiation in liver.« less

Argon laser phototherapy could eliminate the damage effects induced by the ionizing radiation "gamma radiation" in irradiated rabbits.

PubMed

Abdul-Aziz, Karolin Kamel; Tuorkey, M J

2010-04-02

The ionizing radiations could be taken in considerate as an integral part in our life, since, living organisms are actually exposed to a constant shower of ionizing radiations whether from the natural or artificial resources. The radio-protective efficiency of several chemicals has been confirmed in animal trails, whereas, due to their accumulative toxicity, their clinical utility is limited. Therefore, we aimed in the present work to investigate the possibility of using argon laser to recuperate the damaged tissues due to exposing to the ionizing radiation. The rabbits were used in this study, and they were designed as control, gamma irradiated, laser, and gamma plus laser groups. Lipid peroxidation, reduced glutathione (GSH), glutathione peroxidase (GSH-Px) and glucose-6-phosphate dehydrogenase (G-6-PD) in blood and liver were evaluated. As well as, the level of protein thiol was evaluated in the plasma among each group. Results of this study revealed the potential therapeutic performance of the treatment by laser argon to decline the damaging effect of the ionized radiation whether at systematic or local levels. In conclusion, argon laser therapy appears propitious protective effect against the hazard effects of gamma radiation. Copyright 2010 Elsevier B.V. All rights reserved.

Discovery of localized TeV gamma-ray sources and diffuse TeV gamma-ray emission from the galactic plane with Milagro using a new background rejection technique

NASA Astrophysics Data System (ADS)

Abdo, Aws Ahmad

2007-08-01

Very high energy gamma-rays can be used to probe some of the most powerful astrophysical objects in the universe, such as active galactic nuclei, supernova remnants and pulsar-powered nebulae. The diffuse gamma radiation arising from the interaction of cosmic-ray particles with matter and radiation in the Galaxy is one of the few probes available to study the origin of cosmic- rays. Milagro is a water Cherenkov detector that continuously views the entire overhead sky. The large field-of-view combined with the long observation time makes Milagro the most sensitive instrument available for the study of large, low surface brightness sources such as the diffuse gamma radiation arising from interactions of cosmic radiation with interstellar matter. In this thesis I present a new background rejection technique for the Milagro detector through the development of a new gamma hadron separation variable. The Abdo variable, A 4 , coupled with the weighting analysis technique significantly improves the sensitivity of the Milagro detector. This new analysis technique resulted in the first discoveries in Milagro. Four localized sources of TeV gamma-ray emission have been discovered, three of which are in the Cygnus region of the Galaxy and one closer to the Galactic center. In addition to these localized sources, a diffuse emission of TeV gamma-rays has been discovered from the Cygnus region of the Galaxy as well. However, the TeV gamma-ray flux as measured at ~12 TeV from the Cygnus region exceeds that predicted from a conventional model of cosmic-ray production and propagation. This observation indicates the existence of either hard-spectrum cosmic-ray sources and/or other sources of TeV gamma rays in the region. Other TeV gamma-ray source candidates with post-trial statistical significances of > 4s have also been observed in the Galactic plane.

Irradiation disinfestation and decontamination of Iranian dates and pistachio nuts

NASA Astrophysics Data System (ADS)

Zare, Z.; Sayhoon, M.; Maghsoudi, V.

1993-07-01

Decontamination and disinfestation effect of gamma radiation on microflora of dates and artificially infested packed dates (Mazafaty, Zard and Sayer variety) with Tribolium Confusum, Oryzaephilus Surinamensis and Ephestia Cautella in different stages studied. Treatment with 0.75 kGy dose of gamma radiation leads to complete and satisfactory insect disinfestation of dates during a storage period of 9, 20 and 35 days. This study shows that microbiological quality of Mazafaty dates can be significantly improved when they have received a gamma radiation dose of 2.5 kGy. Finally the sugar content of irradiated and unirradiated samples have compared. In this study, we have also used gamma radiation treatment for the control of microbial spoilage of pistachio nuts caused by toxigenic Aspergillus Flavus. The first sequence involved, the freshly harvested pistachio nuts inoculated with A. Flavus spores and exposed to radiation treatment, then retention of samples in a environmental chamber, set at temperature of 15-20 C at 75-80% relative humidity and stored for six months. In the second sequence during the storage period the changes in protein, lipid content of pistachio nuts have analyzed.

3-dimensional imaging system using crystal diffraction lenses

DOEpatents

Smither, R.K.

1999-02-09

A device for imaging a plurality of sources of x-ray and gamma-ray radiation is provided. Diffracting crystals are used for focusing the radiation and directing the radiation to a detector which is used for analyzing their addition to collect data as to the location of the source of radiation. A computer is used for converting the data to an image. The invention also provides for a method for imaging x-ray and gamma radiation by supplying a plurality of sources of radiation; focusing the radiation onto a detector; analyzing the focused radiation to collect data as to the type and location of the radiation; and producing an image using the data. 18 figs.

Very High-Energy Gamma-Ray Sources.

ERIC Educational Resources Information Center

Weekes, Trevor C.

1986-01-01

Discusses topics related to high-energy, gamma-ray astronomy (including cosmic radiation, gamma-ray detectors, high-energy gamma-ray sources, and others). Also considers motivation for the development of this field, the principal results to date, and future prospects. (JN)

Variation in the structure and optical properties of gamma-irradiated Vanadyl 2,3-naphthalocyanine (VONc) nanostructure films

NASA Astrophysics Data System (ADS)

Darwish, A. A. A.; Issa, Shams A. M.

2018-07-01

Naphthalocyanines have an important optical and electrical property, made it eligible to be a key utilitarian materials for a couple of special applications. Therefore, this study focused on the influence of gamma rays irradiation on the structure and optical properties of Vanadyl 2,3-naphthalocyanine (VONc) films. The VONc films have been prepared using the thermal evaporating technique. The investigated films were irradiated with gamma-rays 20, 40 and 60 kGy doses. X-ray diffraction exhibited that the as-deposited VONc films have nanostructure nature, which changed to the amorphous structure with gamma-rays radiation dosage. The optical results indicate that the optical absorption mechanism complied with the indirect allowed transition. It was observed also, there were no prominent changes found in the energy gap values when VONc films were exposed to gamma radiation. However, the optical conductivity rises with additional amounts of gamma-ray dose. This behavior may be attributed to the addition of electrons which freed by the incident photon energy because of a few changes in the film structure caused by the gamma-ray radiation. These outcomes illustrated that VONc films own the characteristics to be utilized in the field of optoelectronic applications.

A STUDY OF THE EFFECT OF GAMMA RADIATION ON APPLES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smock, R.M.; Sparrow, A.H.

1957-01-01

Gamma radiation (cobalt source) of Rhode Island Greening apples did not lower the respiration rate. The 40,000 r lot had a higher than normal rate. This lot also softened more during the holding period at.74 deg F. Dosages over 10,000 r seemed to aggravate mealy breakdown. Dosages of 20,000 amd 40,000 r reduced the production of ethylene and volatiles other than ethylene. The respiration rate of Cortland apples was reduced slightly by gamma radiation. Keeping quality of this variety in storage was not affected, except for the 30,000 r lot which was slightly softer. Weight losses were not affected bymore » radiation. No commercially important benefits were observed with either variety. (auth)« less

Effect of Long Term Low-Level Gamma Radiation on Thermal Sensitivity of RDX/HMX Mixtures

DTIC Science & Technology

1976-11-01

1.1x10 R. It was concluded that the slight exothermic reaction before the 3^6 HMX polymorphic transition could be caused by a radiation-induced...Radiation on Thermal Sensitivity of RDX / HMX Mixtures 5. TYPE OF REPORT 4 PERIOD COVERED Final Report 6. PERFORMING ORG. REPORT NUMBER 7...and Identity by block number) Gamma radiation Weight loss HMX Impact sensitivity test RDX Vacuum stability test DTA Infrared spectrometry TGA

Radiation evaluation study of LSI RAM technologies

NASA Astrophysics Data System (ADS)

Dinger, G. L.; Knoll, M. G.

1980-01-01

Five commercial LSI static random access memory technologies having a 1 kilobit capacity were radiation characterized. Arrays from the transistor-transistor-logic (TTL), Schottky TTL, n-channel metal oxide semiconductor, complementary metal oxide semiconductor (CMOS), and CMOS/silicon on sapphire families were evaluated. Radiation failure thresholds for gamma doserate logic upset, total gamma dose survivability, and neutron fluence survivability were determined. A brief analysis of the radiation failure mechanism for each of the logic families tested is included.

Potential Protective Effects of Ursolic Acid against Gamma Irradiation-Induced Damage Are Mediated through the Modulation of Diverse Inflammatory Mediators

PubMed Central

Wang, Hong; Sim, Meng-Kwoon; Loke, Weng Keong; Chinnathambi, Arunachalam; Alharbi, Sulaiman Ali; Tang, Feng Ru; Sethi, Gautam

2017-01-01

This study was aimed to evaluate the possible protective effects of ursolic acid (UA) against gamma radiation induced damage both in vitro as well as in vivo. It was observed that the exposure to gamma radiation dose- and time-dependently caused a significant decrease in the cell viability, while the treatment of UA attenuated this cytotoxicity. The production of free radicals including reactive oxygen species (ROS) and NO increased significantly post-irradiation and further induced lipid peroxidation and oxidative DNA damage in cells. These deleterious effects could also be effectively blocked by UA treatment. In addition, UA also reversed gamma irradiation induced inflammatory responses, as indicated by the decreased production of TNF-α, IL-6, and IL-1β. NF-κB signaling pathway has been reported to be a key mediator involved in gamma radiation-induced cellular damage. Our results further demonstrated that gamma radiation dose- and time-dependently enhanced NF-κB DNA binding activity, which was significantly attenuated upon UA treatment. The post-irradiation increase in the expression of both phospho-p65, and phospho-IκBα was also blocked by UA. Moreover, the treatment of UA was found to significantly prolong overall survival in mice exposed to whole body gamma irradiation, and reduce the excessive inflammatory responses. Given its radioprotective efficacy as described here, UA as an antioxidant and NF-κB pathway blocker, may function as an important pharmacological agent in protecting against gamma irradiation-induced injury. PMID:28670276

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inoue, Yoshiyuki; Tanaka, Yasuyuki T., E-mail: yinoue@astro.isas.jaxa.jp

The Fermi gamma-ray space telescope has revolutionized our understanding of the cosmic gamma-ray background radiation in the GeV band. However, investigation on the cosmic TeV gamma-ray background radiation still remains sparse. Here, we report the lower bound on the cosmic TeV gamma-ray background spectrum placed by the cumulative flux of individual detected extragalactic TeV sources including blazars, radio galaxies, and starburst galaxies. The current limit on the cosmic TeV gamma-ray background above 0.1 TeV is obtained as 2.8 × 10{sup −8}(E/100 GeV){sup −0.55} exp(−E/2100GeV)[GeV cm{sup −2} s{sup −1} sr{sup −1}] < E{sup 2}dN/dE < 1.1 × 10{sup −7}(E/100 GeV){sup −0.49} [GeV cm{sup −2} s{sup −1} sr{sup −1}], wheremore » the upper bound is set by requirement that the cascade flux from the cosmic TeV gamma-ray background radiation can not exceed the measured cosmic GeV gamma-ray background spectrum. Two nearby blazars, Mrk 421 and Mrk 501, explain ∼70% of the cumulative background flux at 0.8–4 TeV, while extreme blazars start to dominate at higher energies. We also provide the cumulative background flux from each population, i.e., blazars, radio galaxies, and starburst galaxies which will be the minimum requirement for their contribution to the cosmic TeV gamma-ray background radiation.« less

Methodology trends on gamma and electron radiation damage simulation studies in solids under high fluency irradiation environments

NASA Astrophysics Data System (ADS)

Cruz Inclán, Carlos M.; González Lazo, Eduardo; Rodríguez Rodríguez, Arturo; Guzmán Martínez, Fernando; Abreu Alfonso, Yamiel; Piñera Hernández, Ibrahin; Leyva Fabelo, Antonio

2017-09-01

The present work deals with the numerical simulation of gamma and electron radiation damage processes under high brightness and radiation particle fluency on regard to two new radiation induced atom displacement processes, which concern with both, the Monte Carlo Method based numerical simulation of the occurrence of atom displacement process as a result of gamma and electron interactions and transport in a solid matrix and the atom displacement threshold energies calculated by Molecular Dynamic methodologies. The two new radiation damage processes here considered in the framework of high brightness and particle fluency irradiation conditions are: 1) The radiation induced atom displacement processes due to a single primary knockout atom excitation in a defective target crystal matrix increasing its defect concentrations (vacancies, interstitials and Frenkel pairs) as a result of a severe and progressive material radiation damage and 2) The occurrence of atom displacements related to multiple primary knockout atom excitations for the same or different atomic species in an perfect target crystal matrix due to subsequent electron elastic atomic scattering in the same atomic neighborhood during a crystal lattice relaxation time. In the present work a review numeral simulation attempts of these two new radiation damage processes are presented, starting from the former developed algorithms and codes for Monte Carlo simulation of atom displacements induced by electron and gamma in

Investigation of natural effective gamma dose rates case study: Ardebil Province in Iran

PubMed Central

2012-01-01

Gamma rays pose enough energy to induce chemical changes that may be biologically important for the normal functioning of body cells. The external exposure of human beings to natural environmental gamma radiation normally exceeds that from all man-made sources combined. In this research natural background gamma dose rates and corresponding annual effective doses were determined for selected cities of Ardebil province. Outdoor gamma dose rates were measured using an Ion Chamber Survey Meter in 105 locations in selected districts. Average absorbed doses for Ardebil, Sar-Ein, Germy, Neer, Shourabil Recreational Lake, and Kosar were determined as 265, 219, 344, 233, 352, and 358 nSv/h, respectively. Although dose rates recorded for Germi and Kosar are comparable with some areas with high natural radiation background, however, the dose rates in other districts are well below the levels reported for such locations. Average annual effective dose due to indoor and outdoor gamma radiation for Ardebil province was estimated as 1.73 (1.35–2.39) mSv, which is on average 2 times higher than the world population weighted average. PMID:23369115

Gamma-radiation monitoring in post-tectonic biotitic granites at Celorico da Beira

NASA Astrophysics Data System (ADS)

Domingos, Filipa; Barbosa, Susana; Pereira, Alcides; Neves, Luís

2017-04-01

Despite its obvious relevance, the effect of meteorological variables such as temperature, pressure, wind, rainfall and particularly humidity on the temporal variability of natural radiation is complex and still not fully understood. Moreover, the nature of their influence with increasing depth is also poorly understood. Thereby, two boreholes were set 3 m apart in the region of Celorico da Beira within post-tectonic biotitic granites of the Beiras Batolith. Continuous measurements were obtained with identical gamma-ray scintillometers deployed at depths of 1 and 6 m during a 6 month period in the years of 2014 and 2015. Temperature, relative humidity, pressure, rainfall, wind speed and direction were measured at the site, as well as temperature and relative humidity inside the boreholes, with the aim of assessing the influence of meteorological parameters on the temporal variability of gamma radiation at two distinct depths. Both time series display a complex temporal structure including multiyear, seasonal and daily variability. At 1 m depth, a daily periodicity on the gamma ray counts time series was noticed with daily maxima occurring most frequently from 8 to 12 p.m. and daily minima between 8 and 12 a.m.. At 6 m depth, maximum and minimum daily means occurred with approximately a 10 h lag from the above. Gamma radiation data exhibited fairly strong correlations with temperature and relative humidity, however, varying with depth. Gamma radiation counts increased with increasing temperature and decreasing relative humidity at 1 m depth, while at a 6 m depth the opposite was recorded, with counts increasing with relative humidity and decreasing with temperature. Wind speed was shown to be inversely related with counts at 6 m depth, while positively correlated at 1 m depth. Pressure and rainfall had minor effects on both short-term and long-term gamma radiation counts.

Nuclear radiation-warning detector that measures impedance

DOEpatents

Savignac, Noel Felix; Gomez, Leo S; Yelton, William Graham; Robinson, Alex; Limmer, Steven

2013-06-04

This invention is a nuclear radiation-warning detector that measures impedance of silver-silver halide on an interdigitated electrode to detect light or radiation comprised of alpha particles, beta particles, gamma rays, X rays, and/or neutrons. The detector is comprised of an interdigitated electrode covered by a layer of silver halide. After exposure to alpha particles, beta particles, X rays, gamma rays, neutron radiation, or light, the silver halide is reduced to silver in the presence of a reducing solution. The change from the high electrical resistance (impedance) of silver halide to the low resistance of silver provides the radiation warning that detected radiation levels exceed a predetermined radiation dose threshold.

Gamma Radiation from PSR B1055-52

NASA Technical Reports Server (NTRS)

Thompson, D. J.; Bailes, M.; Bertsch, D. L.; Cordes, J.; DAmico, N. D.; Esposito, J. A.; Finley, J.; Hartman, R. C.; Hermsen, W.; Kanbach, G.;

Experimental search for the radiative capture reaction d + d {yields} {sup 4}He + {gamma} from the dd{mu} muonic molecule state J = 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baluev, V. V.; Bogdanova, L. N.; Bom, V. R.

2011-07-15

A search for the muon-catalyzed fusion reaction d + d {yields} {sup 4}He + {gamma} in the dd{mu} muonic molecule was performed using the experimental installation TRITON with BGO detectors for {gamma}-quanta. A high-pressure target filled with deuterium was exposed to the negative muon beam of the JINR Phasotron to detect {gamma}-quanta with the energy 23.8 MeV. An experimental estimation for the yield of radiative deuteron capture from the dd{mu} state J = 1 was obtained at the level of {eta}{sub {gamma}} {<=} 8 Multiplication-Sign 10{sup -7} per fusion.

Gamma Radiation from PSR B1055-52

NASA Technical Reports Server (NTRS)

Thompson, D. J.; Bailes, M.; Bertsch, D. L.; Cordes, J.; DAmico, N.; Esposito, J. A.; Finley, J.; Hartman, R. C.; Hermsen, W.; Kanbach, G.;

Some Radiation Techniques Used in the GU-3 Gamma Irradiator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dodbiba, Andon; Ylli, Ariana; Stamo, Iliriana

2007-04-23

Different radiation techniques, measurement of dose and its distibution throughout the irradiated materials are the main problems treated in this paper. The oscillometry method combined with the ionization chamber, as an absolute dosimeter, is used for calibration of routine ECB dosimeters. The dose uniformity, for the used radiation techniques in our GU-3 Gamma Irradiator with Cs-137, is from 93% up to 99%.

Evaluation of DNA damage induced by gamma radiation in gill and muscle tissues of Cyprinus carpio and their relative sensitivity.

PubMed

M K, Praveen Kumar; Shyama, Soorambail K; D'Costa, Avelyno; Kadam, Samit B; Sonaye, Bhagatsingh Harisingh; Chaubey, Ramesh Chandra

2017-10-01

The effect of radiation on the aquatic environment is of major concern in recent years. Limited data is available on the genotoxicity of gamma radiation on different tissues of aquatic organisms. Hence, the present investigation was carried out to study the DNA damage induced by gamma radiation in the gill and muscle tissues and their relative sensitivity using the comet assay in the freshwater teleost fish, common carp (Cyprinus carpio). The comet assay was optimized and validated in common carp using cyclophosphamide (CP), a reference genotoxic agent. The fish were exposed (acute) to various doses of gamma radiation (2, 4, 6, 8 and 10Gy) and samplings (gill and muscle tissue) were done at regular intervals (24, 48 and 72h) to assess the DNA damage. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA for all doses of gamma radiation in both tissues. We also observed a dose-related increase and a time-dependent decrease of DNA damage. In comparison, DNA damage showed different sensitivity among the tissues at different doses. This shows that a particular dose may have different effects on different tissues which could be due to physiological factors of the particular tissue. Our study also suggests that the gills and muscle of fish are sensitive and reliable tissues for evaluating the genotoxic effects of reference and environmental agents, using the comet assay. Copyright © 2017. Published by Elsevier Inc.

Dosimetric evaluation of lithium carbonate (Li2CO3) as a dosemeter for gamma-radiation dose measurements.

PubMed

Popoca, R; Ureña-Núñez, F

2009-06-01

This work reports the possibility of using lithium carbonate as a dosimetric material for gamma-radiation measurements. Carboxi-radical ions, CO(2)(-) and CO(3)(-), arise from the gamma irradiation of Li(2)CO(3), and these radical ions can be quantified by electron paramagnetic resonance (EPR) spectrometry. The EPR-signal response of gamma-irradiated lithium carbonate has been investigated to determine some dosimetric characteristics such as: peak-to-peak signal intensity versus gamma dose received, zero-dose response, signal fading, signal repeatability, batch homogeneity, dose rate effect and stability at different environmental conditions. Using the conventional peak-to-peak method of stable ion radicals, it is concluded that lithium carbonate could be used as a gamma dosemeter in the range of 3-100 Gy.

LaCl3:Ce Coincidence Signatures to Calibrate Gamma-ray Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

McIntyre, Justin I.; Schrom, Brian T.; Cooper, Matthew W.

Abstract Calibrating the gamma-ray detection efficiency of radiation detectors in a field environment is difficult under most circumstances. To counter this problem we have developed a technique that uses a Cerium doped Lanthanum-Tri-Chloride (LaCl3:Ce) scintillation detector to provide gated gammas[ , ]. Exploiting the inherent radioactivity of the LaCl3:Ce due to the long-lived radioactive isotope 138La (t1/2 = 1.06 x 1011 yrs) allows the use of the 788 and 1436-keV gammas as a measure of efficiency. In this paper we explore the effectiveness of using the beta-gamma coincidences radiation LaCl3:Ce detector to calibrate the energy and efficiency of a numbermore » of gamma-ray detectors.« less

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

PubMed

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

2006-08-30

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

29 CFR 570.57 - Exposure to radioactive substances and to ionizing radiations (Order 6).

Code of Federal Regulations, 2011 CFR

2011-07-01

... alpha and beta particles, electrons, protons, neutrons, gamma and X-ray and all other radiations which... gamma and X-ray. [22 FR 3657, May 24, 1957, as amended at 26 FR 8885, Sept. 21, 1961. Redesignated at 28...

Field-deployable gamma-radiation detectors for DHS use

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Sanjoy

2007-09-01

Recently, the Department of Homeland Security (DHS) has integrated all nuclear detection research, development, testing, evaluation, acquisition, and operational support into a single office: the Domestic Nuclear Detection Office (DNDO). The DNDO has specific requirements set for all commercial off-the-shelf and government off-the-shelf radiation detection equipment and data acquisition systems. This article would investigate several recent developments in field deployable gamma radiation detectors that are attempting to meet the DNDO specifications. Commercially available, transportable, handheld radio isotope identification devices (RIID) are inadequate for DHS' requirements in terms of sensitivity, resolution, response time, and reach-back capability. The leading commercial vendor manufacturing handheld gamma spectrometer in the United States is Thermo Electron Corporation. Thermo Electron's identiFINDER TM, which primarily uses sodium iodide crystals (3.18 x 2.54cm cylinders) as gamma detectors, has a Full-Width-at-Half-Maximum energy resolution of 7 percent at 662 keV. Thermo Electron has just recently come up with a reach-back capability patented as RadReachBack TM that enables emergency personnel to obtain real-time technical analysis of radiation samples they find in the field1. The current project has the goal to build a prototype handheld gamma spectrometer, equipped with a digital camera and an embedded cell phone to be used as an RIID with higher sensitivity, better resolution, and faster response time (able to detect the presence of gamma-emitting radio isotopes within 5 seconds of approach), which will make it useful as a field deployable tool. The handheld equipment continuously monitors the ambient gamma radiation, and, if it comes across any radiation anomalies with higher than normal gamma gross counts, it sets an alarm condition. When a substantial alarm level is reached, the system automatically triggers the saving of relevant spectral data and software-triggers the digital camera to take a snapshot. The spectral data including in situ analysis and the imagery data will be packaged in a suitable format and sent to a command post using an imbedded cell phone.

Using a smart phone application to measure high-energy radiation from thunderstorms

NASA Astrophysics Data System (ADS)

Bowers, G. S.; Smith, D. M.; Rexroad, W. Z.; Kelley, N. A.; Martinez-Mckinney, F.; Rubenstein, E. P.; Drukier, G.; Benes, G. N.

2013-12-01

Commercial airline flights and developing cell phone technologies present a burgeoning opportunity for the public to help investigate radiation from thunderstorms, including terrestrial gamma-ray flashes (TGFs), longer-lived gamma-ray glows, x-rays from lightning stepped leaders, and possible high-energy radiation, never yet observed, from blue jets, gigantic jets, and blue starters. GammaPix is a smartphone application from Image Insight, Inc. that uses the camera's CCD or CMOS sensor to identify and qualitatively assess threats related to gamma radioactivity, e.g., those caused by accidental exposure to radioactive material, high-altitude air travel, or acts of terrorism. A science-oriented version of the app is under development that will be publicized for use aboard commercial airline flights and on the ground in regions (like Japan in the wintertime) where thunderstorm charge centers come close to the ground. The primary goal of the project is to learn whether TGFs close to passenger aircraft and population centers on the ground occur often enough to create concern about radiation risk.

Method for non-intrusively identifying a contained material utilizing uncollided nuclear transmission measurements

DOEpatents

Morrison, John L.; Stephens, Alan G.; Grover, S. Blaine

2001-11-20

An improved nuclear diagnostic method identifies a contained target material by measuring on-axis, mono-energetic uncollided particle radiation transmitted through a target material for two penetrating radiation beam energies, and applying specially developed algorithms to estimate a ratio of macroscopic neutron cross-sections for the uncollided particle radiation at the two energies, where the penetrating radiation is a neutron beam, or a ratio of linear attenuation coefficients for the uncollided particle radiation at the two energies, where the penetrating radiation is a gamma-ray beam. Alternatively, the measurements are used to derive a minimization formula based on the macroscopic neutron cross-sections for the uncollided particle radiation at the two neutron beam energies, or the linear attenuation coefficients for the uncollided particle radiation at the two gamma-ray beam energies. A candidate target material database, including known macroscopic neutron cross-sections or linear attenuation coefficients for target materials at the selected neutron or gamma-ray beam energies, is used to approximate the estimated ratio or to solve the minimization formula, such that the identity of the contained target material is discovered.

Pretreatment of low dose radiation reduces radiation-induced apoptosis in mouse lymphoma (EL4) cells.

PubMed

Kim, J H; Hyun, S J; Yoon, M Y; Ji, Y H; Cho, C K; Yoo, S Y

1997-06-01

Induction of an adaptive response to ionizing radiation in mouse lymphoma (EL4) cells was studied by using cell survival fraction and apoptotic nucleosomal DNA fragmentation as biological end points. Cells in early log phase were pre-exposed to low dose of gamma-rays (0.01 Gy) 4 or 20 hrs prior to high dose gamma-ray (4, 8 and 12 Gy for cell survival fraction analysis; 8 Gy for DNA fragmentation analysis) irradiation. Then cell survival fractions and the extent of DNA fragmentation were measured. Significant adaptive response, increase in cell survival fraction and decrease in the extent of DNA fragmentation were induced when low and high dose gamma-ray irradiation time interval was 4 hr. Addition of protein or RNA synthesis inhibitor, cycloheximide or 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole (DRFB), respectively during adaptation period, the period from low dose gamma-ray irradiation to high dose gamma-ray irradiation, was able to inhibit the induction of adaptive response, which is the reduction of the extent DNA fragmentation in irradiated EL4 cells. These data suggest that the induction of adaptive response to ionizing radiation in EL4 cells required both protein and RNA synthesis.

Evaluation of gamma dose effect on PIN photodiode using analytical model

NASA Astrophysics Data System (ADS)

Jafari, H.; Feghhi, S. A. H.; Boorboor, S.

2018-03-01

The PIN silicon photodiodes are widely used in the applications which may be found in radiation environment such as space mission, medical imaging and non-destructive testing. Radiation-induced damage in these devices causes to degrade the photodiode parameters. In this work, we have used new approach to evaluate gamma dose effects on a commercial PIN photodiode (BPX65) based on an analytical model. In this approach, the NIEL parameter has been calculated for gamma rays from a 60Co source by GEANT4. The radiation damage mechanisms have been considered by solving numerically the Poisson and continuity equations with the appropriate boundary conditions, parameters and physical models. Defects caused by radiation in silicon have been formulated in terms of the damage coefficient for the minority carriers' lifetime. The gamma induced degradation parameters of the silicon PIN photodiode have been analyzed in detail and the results were compared with experimental measurements and as well as the results of ATLAS semiconductor simulator to verify and parameterize the analytical model calculations. The results showed reasonable agreement between them for BPX65 silicon photodiode irradiated by 60Co gamma source at total doses up to 5 kGy under different reverse voltages.

Radiation Characterization Summary: ACRR Cadmium-Polyethylene (CdPoly) Bucket Located in the Central Cavity on the 32-Inch Pedestal at the Core Centerline

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parma, Edward J.; Naranjo, Gerald E.; Kaiser, Krista Irene

This document presents the facility-recommended characterization of the neutron, prompt gamma-ray, and delayed gamma-ray radiation fields in the Annular Core Research Reactor (ACRR) for the cadmium-polyethylene (CdPoly) bucket in the central cavity on the 32-inch pedestal at the core centerline. The designation for this environment is ACRR-CdPoly-CC-32-cl. The neutron, prompt gamma-ray, and delayed gamma-ray energy spectra, uncertainties, and covariance matrices are presented as well as radial and axial neutron and gamma-ray fluence profiles within the experiment area of the bucket. Recommended constants are given to facilitate the conversion of various dosimetry readings into radiation metrics desired by experimenters. Representative pulsemore » operations are presented with conversion examples. Acknowledgements The authors wish to thank the Annular Core Research Reactor staff and the Radiation Metrology Laboratory staff for their support of this work. Also thanks to Drew Tonigan for helping field the activation experiments in ACRR, David Samuel for helping to finalize the drawings and get the parts fabricated, and Elliot Pelfrey for preparing the active dosimetry plots.« less

CONSTRAINING THE EMISSIVITY OF ULTRAHIGH ENERGY COSMIC RAYS IN THE DISTANT UNIVERSE WITH THE DIFFUSE GAMMA-RAY EMISSION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Xiangyu; Liu Ruoyu; Aharonian, Felix

Ultrahigh cosmic rays (UHECRs) with energies {approx}> 10{sup 19} eV emitted at cosmological distances will be attenuated by cosmic microwave and infrared background radiation through photohadronic processes. Lower energy extragalactic cosmic rays ({approx}10{sup 18}-10{sup 19} eV) can only travel a linear distance smaller than {approx}Gpc in a Hubble time due to the diffusion if the extragalactic magnetic fields are as strong as nano-Gauss. These prevent us from directly observing most of the UHECRs in the universe, and thus the observed UHECR intensity reflects only the emissivity in the nearby universe within hundreds of Mpc. However, UHECRs in the distant universe,more » through interactions with the cosmic background photons, produce UHE electrons and gamma rays that in turn initiate electromagnetic cascades on cosmic background photons. This secondary cascade radiation forms part of the extragalactic diffuse GeV-TeV gamma-ray radiation and, unlike the original UHECRs, is observable. Motivated by new measurements of extragalactic diffuse gamma-ray background radiation by Fermi/Large Area Telescope, we obtained upper limit placed on the UHECR emissivity in the distant universe by requiring that the cascade radiation they produce not exceed the observed levels. By comparison with the gamma-ray emissivity of candidate UHECR sources (such as gamma-ray bursts (GRBs) and active galactic nuclei) at high redshifts, we find that the obtained upper limit for a flat proton spectrum is {approx_equal} 10{sup 1.5} times larger than the gamma-ray emissivity in GRBs and {approx_equal} 10 times smaller than the gamma-ray emissivity in BL Lac objects. In the case of iron nuclei composition, the derived upper limit of UHECR emissivity is a factor of 3-5 times higher. Robust upper limit on the cosmogenic neutrino flux is further obtained, which is marginally reachable by the Icecube detector and the next-generation detector JEM-EUSO.« less

Radiative Penguin Decays at the B Factories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koneke, Karsten; /MIT, LNS

2007-11-16

In this article, I review the most recent results in radiative penguin decays from the B factories Belle and BABAR. Most notably, I will talk about the recent new observations in the decays B {yields} ({rho}/{omega}) {gamma}, a new analysis technique in b {yields} s{gamma}, and first measurements of radiative penguin decays in the B{sup 0}{sub s} meson system. Finally, I will summarize the current status and future prospects of radiative penguin B physics at the B factories.

Gamma Radiation (5-10 Gy) Impairs Neuronal Function in the Guinea Pig Hippocampus

DTIC Science & Technology

1993-01-01

Radiation (5-10 Gy) Impairs Neuronal Function in the Guinea Pig Hippocampus TERRY C. PELLMAR AND DENNIS L. LEPINSKI Ph.vsiology Department..Irmned Forces...L. Gamma Radiation ioral effects. Within hours of irradiation with 10 Gy and (5- 10 Gy) Impairs Neuronal Function in the Guinea Pig Hippo- less...acti v- Guinea pigs were exposed to 5 and 10 Gy ’y radiation. Hippo- ity (9) are evident. campal brain slices were isolated 30 min, I day, 3 days and 5

Toward advanced gamma rays radiation resistance and shielding efficiency with phthalonitrile resins and composites

NASA Astrophysics Data System (ADS)

Derradji, Mehdi; Zegaoui, Abdeldjalil; Xu, Yi-Le; Wang, An-ran; Dayo, Abdul Qadeer; Wang, Jun; Liu, Wen-bin; Liu, Yu-Guang; Khiari, Karim

2018-04-01

The phthalonitrile resins have claimed the leading place in the field of high performance polymers thanks to their combination of outstanding properties. The present work explores for the first time the gamma rays radiation resistance and shielding efficiency of the phthalonitrile resins and its related tungsten-reinforced nanocomposites. The primary goal of this research is to define the basic behavior of the phthalonitrile resins under highly ionizing gamma rays. The obtained results confirmed that the neat phthalonitrile resins can resist absorbed doses as high as 200 kGy. Meanwhile, the remarkable shielding efficiency of the phthalonitrile polymers was confirmed to be easily improved by preparing lead-free nanocomposites. In fact, the gamma rays screening ratio reached the exceptional value of 42% for the nanocomposites of 50 wt% of nano-tungsten loading. Thus, this study confirms that the remarkable performances of the phthalonitrile resins are not limited to the thermal and mechanical properties and can be extended to the gamma rays radiation and shielding resistances.

Comparison of structural changes in skin and amnion tissue grafts for transplantation induced by gamma and electron beam irradiation for sterilization.

PubMed

Mrázová, H; Koller, J; Kubišová, K; Fujeríková, G; Klincová, E; Babál, P

2016-06-01

Sterilization is an important step in the preparation of biological material for transplantation. The aim of the study is to compare morphological changes in three types of biological tissues induced by different doses of gamma and electron beam radiation. Frozen biological tissues (porcine skin xenografts, human skin allografts and human amnion) were irradiated with different doses of gamma rays (12.5, 25, 35, 50 kGy) and electron beam (15, 25, 50 kGy). Not irradiated specimens served as controls. The tissue samples were then thawn and fixed in 10 % formalin, processed by routine paraffin technique and stained with hematoxylin and eosin, alcian blue at pH 2.5, orcein, periodic acid Schiff reaction, phosphotungstic acid hematoxylin, Sirius red and silver impregnation. The staining with hematoxylin and eosin showed vacuolar cytoplasmic changes of epidermal cells mainly in the samples of xenografts irradiated by the lowest doses of gamma and electron beam radiation. The staining with orcein revealed damage of fine elastic fibers in the xenograft dermis at the dose of 25 kGy of both radiation types. Disintegration of epithelial basement membrane, especially in the xenografts, was induced by the dose of 15 kGy of electron beam radiation. The silver impregnation disclosed nuclear chromatin condensation mainly in human amnion at the lowest doses of both radiation types and disintegration of the fine collagen fibers in the papillary dermis induced by the lowest dose of electron beam and by the higher doses of gamma radiation. Irradiation by both, gamma rays and the electron beam, causes similar changes on cells and extracellular matrix, with significant damage of the basement membrane and of the fine and elastic and collagen fibers in the papillary dermis, the last caused already by low dose electron beam radiation.

Risk Factors: Radiation

Cancer.gov

Radiation of certain wavelengths, called ionizing radiation, has enough energy to damage DNA and cause cancer. Ionizing radiation includes radon, x-rays, gamma rays, and other forms of high-energy radiation.

Nudat 2

Science.gov Websites

modes), gamma rays (energy, intensity, multipolarity, coinc.) Nuclear Wallet Cards Search Latest Ground NuDat 2.7 Levels and Gammas Search Ground and excited states (energy, T1/2, spin/parity, decay and isomeric states properties Decay Radiation Search Radiation type, energy, intensity and dose

Seabuckthron (Hippophae rhamnoides L.) leaf extract ameliorates the gamma radiation mediated DNA damage and hepatic alterations.

PubMed

Khan, Amitava; Manna, Krishnendu; Chinchubose; Das, Dipesh Kr; Sinha, Mahuya; Kesh, Swaraj Bandhu; Das, Ujjal; Dey, Rakhi Sharma; Banerji, Asoke; Dey, Sanjit

2014-10-01

In vitro assessment showed that H. rhamnoides (HrLE) extract possessed free radical scavenging activities and can protect gamma (gamma) radiation induced supercoiled DNA damage. For in vivo study, Swiss albino mice were administered with HrLE (30 mg/kg body weight) for 15 consecutive days before exposing them to a single dose of 5 Gy of beta radiation. HrLE significantly prevented the radiation induced genomic DNA damage indicated as a significant reduction in the comet parameters. The lipid peroxidation, liver function enzymes, expression of phosphorylated NFkappaB (p65) and IkappaBalpha increased whereas the endogenous antioxidants diminished upon radiation exposure compared to control. Pretreatment of HrLE extract ameliorated these changes. Based on the present results it can be concluded that H. rhamnoides possess a potential preventive element in planned and accidental nuclear exposures.

Electromagnetic cascades in pulsars

NASA Technical Reports Server (NTRS)

Daugherty, J. K.; Harding, A. K.

1981-01-01

The development of pair photon cascades initiated by high energy electrons above a pulsar polar cap is simulated numerically. The calculation uses the energy of the primary electron, the magnetic field strength, and the period of rotation as parameters and follows the curvature radiation emitted by the primary, the conversion of this radiation e(+) - e(-) pairs in the intense fields, and the quantized synchrotron radiation by the secondary pairs. A recursive technique allows the tracing of an indefinite number of generations using a Monte Carlo method. Gamma ray and pair spectra are calculated for cascades in different parts of the polar cap and with different acceleration models. It is found that synchrotron radiation from secondary pairs makes an important contribution to the gamma ray spectrum above 25 MeV, and that the final gamma ray and pair spectra are insensitive to the height of the accelerating region, as long as the acceleration of the primary electrons is not limited by radiation reaction.

Radiation shielding composition

DOEpatents

Quapp, William J.; Lessing, Paul A.

2000-12-26

A composition for use as a radiation shield. The shield is a concrete product containing a stable uranium aggregate for attenuating gamma rays and a neutron absorbing component, the uranium aggregate and neutron absorbing component being present in the concrete product in sufficient amounts to provide a concrete having a density between about 4 and about 15 grams/cm.sup.3 and which will at a predetermined thickness, attenuate gamma rays and absorb neutrons from a radioactive material of projected gamma ray and neutron emissions over a determined time period. The composition is preferably in the form of a container for storing radioactive materials that emit gamma rays and neutrons. The concrete container preferably comprises a metal liner and/or a metal outer shell. The resulting radiation shielding container has the potential of being structurally sound, stable over a long period of time, and, if desired, readily mobile.

Radiation shielding composition

DOEpatents

Quapp, William J.; Lessing, Paul A.

1998-01-01

A composition for use as a radiation shield. The shield is a concrete product containing a stable uranium aggregate for attenuating gamma rays and a neutron absorbing component, the uranium aggregate and neutron absorbing component being present in the concrete product in sufficient amounts to provide a concrete having a density between about 4 and about 15 grams/cm.sup.3 and which will at a predetermined thickness, attenuate gamma rays and absorb neutrons from a radioactive material of projected gamma ray and neutron emissions over a determined time period. The composition is preferably in the form of a container for storing radioactive materials that emit gamma rays and neutrons. The concrete container preferably comprises a metal liner and/or a metal outer shell. The resulting radiation shielding container has the potential of being structurally sound, stable over a long period of time, and, if desired, readily mobile.

On neutron-gamma mixed field dosimetry with LiF:Mg,Ti at radiation protection dose levels.

PubMed

Weinstein, M; German, U; Alfassi, Z B

2006-01-01

The possibility of using the specific responses of the high temperature Peaks 6 and 7 and Peaks 4 and 5 to different LET radiations was mentioned in the past mainly for very high doses. The applicability of the two regions method for thermal neutrons--gamma ray mixed field dosimetry was investigated by analysing the response of LiF:Mg,Ti dosemeters irradiated to different ratios of thermal neutrons and gamma rays at radiation protection dose levels encountered in routine work conditions, up to approximately 50 mSv. The Region of Interest method was used to define the areas of the Peaks 4 + 5 and 6 + 7. We found that a simple algorithm can be used to determine with good accuracy the separate contributions of neutron and gamma doses.

Novel Concrete Chemistry Achieved with Low Dose Gamma Radiation Curing and Resistance to Neutron Activation

NASA Astrophysics Data System (ADS)

Burnham, Steven Robert

As much as 50% of ageing-related problems with concrete structures can be attributed to con-struction deficiencies at the time of placement. The most influential time affecting longevity of concrete structures is the curing phase, or commonly the initial 28 days following its placement. A novel advanced atomistic analysis of novel concrete chemistry is presented in this dissertation with the objective to improve concrete structural properties and its longevity. Based on experiments and computational models, this novel concrete chemistry is discussed in two cases: (a) concrete chemistry changes when exposed to low-dose gamma radiation in its early curing stage, thus improving its strength in a shorter period of time then curing for the conventional 28 days; (b) concrete chemistry is controlled by its atomistic components to assure strength is not reduced but that its activation due to long-term exposure to neutron flux in nuclear power plants is negligible. High dose gamma radiation is well documented as a degradation mechanism that decreases concrete's compressive strength; however, the effects of low-dose gamma radiation on the initial curing phase of concrete, having never been studied before, proved its compressive strength increases. Using a 137 Cs source, concrete samples were subjected to gamma radiation during the initial curing phase for seven, 14, and 28 days. The compressive strength after seven days is improved for gamma cured concrete by 24% and after 14 days by 76%. Concrete shows no improvement in compressive strength after 28 days of exposure to gamma radiation, showing that there is a threshold effect. Scanning Electron Microscopy is used to examine the microstructure of low-dose gamma radiation where no damage to its microstructure is found, showing no difference between gamma cured and conventionally cured concrete. Molecular dynamics modeling based on the MOPAC package is used to study how gamma radiation during the curing stage improves compressive strength of concrete. The modeling shows that when radiolysis occurs in freshly mixed concrete, the reactivity between key molecules responsible for bonding between cement and aggregate is enhanced due to improved reactivity at the molecular level. A new method is developed that successfully controls a concrete chemistry at the atomistic level by assuring its long-term exposure to neutron flux in nuclear power plants will not activate the dome wall to the level of low-level radioactive waste. This methodology is established to detect and select the level of trace elemental composition in concrete based on a low-flux neutron activation analysis (NAA). By carefully selecting aggregates that do not contain certain elements that activate to high concentrations after decades of concrete exposure to neutron flux, the end of life for concrete is improved by declassifying it as low-level radioactive waste. Directly, it improves economy of commissioning nuclear power plants to be built in near future and reducing important quantities of waste to be disposed at high costs.

Radioprotective effects of an acidic polysaccharide of Panax ginseng on bone marrow cells.

PubMed

Kim, Hyun Ji; Kim, Mi Hyoung; Byon, Yun Young; Park, Jae Woo; Jee, Youngheun; Joo, Hong Gu

2007-03-01

An acidic polysaccharide of Panax ginseng (APG), so called ginsan is known to have important immunomodulatory activities. It was recently reported that APG has radioprotective effects in mice but the detailed mechanism was not fully elucidated. This study examined the effects of APG on bone marrow cells (BMs). The phenotypical and functional changes in APG-treated BMs after gamma radiation were studied. The benefit of APG on BMs damaged by gamma radiation was determined by measuring the cell viability. Using 2 different assays, a pretreatment with APG significantly increased the viability of BMs against gamma radiation. APG-treated BMs had a significantly higher amount of IL-12, which is a major cytokine for immune responses, compared with the medium-treated BMs. The expression of MHC class II molecules of APG-treated BMs was also increased, and APG-treated BMs showed significantly higher levels of allogeneic CD4(+) T lymphocyte proliferation. Furthermore, APG-treated mice had a larger number of BMs after gamma radiation than the control mice, and the BMs of APG-treated mice were successfully cultured into dendritic cells, which are the representative antigenpresenting cells. Overall, this study shows that APG alters the phenotype of BMs, increases the viability and alloreactivity of BMs after gamma radiation both in vitro and in vivo. Therefore, APG may be a good candidate radioprotective agent for BMs.

Radioprotective effects of an acidic polysaccharide of Panax ginseng on bone marrow cells

PubMed Central

Kim, Hyun-Ji; Kim, Mi-Hyoung; Byon, Yun-Young; Park, Jae Woo; Jee, Youngheun

2007-01-01

An acidic polysaccharide of Panax ginseng (APG), so called ginsan is known to have important immunomodulatory activities. It was recently reported that APG has radioprotective effects in mice but the detailed mechanism was not fully elucidated. This study examined the effects of APG on bone marrow cells (BMs). The phenotypical and functional changes in APG-treated BMs after gamma radiation were studied. The benefit of APG on BMs damaged by gamma radiation was determined by measuring the cell viability. Using 2 different assays, a pretreatment with APG significantly increased the viability of BMs against gamma radiation. APG-treated BMs had a significantly higher amount of IL-12, which is a major cytokine for immune responses, compared with the medium-treated BMs. The expression of MHC class II molecules of APG-treated BMs was also increased, and APG-treated BMs showed significantly higher levels of allogeneic CD4+ T lymphocyte proliferation. Furthermore, APG-treated mice had a larger number of BMs after gamma radiation than the control mice, and the BMs of APG-treated mice were successfully cultured into dendritic cells, which are the representative antigen-presenting cells. Overall, this study shows that APG alters the phenotype of BMs, increases the viability and alloreactivity of BMs after gamma radiation both in vitro and in vivo. Therefore, APG may be a good candidate radioprotective agent for BMs. PMID:17322772

Assessment of thunderstorm neutron radiation environment at altitudes of aviation flights

NASA Astrophysics Data System (ADS)

Drozdov, A.; Grigoriev, A.; Malyshkin, Y.

2013-02-01

High-energy radiation emitted from thunderclouds supposes generation of neutrons in photonuclear reactions of the gamma photons with air. This observation is supported by registration of neutrons during thunderstorm activity in a number of experiments, most of which established correlation with lightning. In this work we perform a modeling of the neutron generation and propagation processes at low atmospheric altitudes using current knowledge of the TGF source properties. On this basis we obtain dosimetric maps of thunderstorm neutron radiation and investigate possible radiation threat for aircraft flights. We estimate the maximal effective neutron dose that potentially can be received on board an aircraft in close proximity to the gamma source, to be of the order of 0.54 mSv over a time less than 0.1 s. This dose is considerably less than estimations obtained earlier for the associated electron and gamma radiation; nevertheless, this value is quite large by itself and under some circumstances the neutron component seems to be the most important for the dosimetric effect. Due to wide distribution in space, the thunderstorm neutrons are thought to also provide a convenient means for experimental investigation of gamma emissions from thunderclouds. To register neutrons from powerful gamma flashes that occur at the tops of thunderclouds, however, in the most favorable case one has to take a location above the 2 km level that is appropriate to mountains or aircraft facilities.

Composition and apparatus for detecting gamma radiation

DOEpatents

Hofstetter, Kenneth J.

1994-01-01

A gamma radiation detector and a radioluminiscent composition for use therein. The detector includes a radioluminscent composition that emits light in a characteristic wavelength region when exposed to gamma radiation, and means for detecting said radiation. The composition contains a scintillant such as anglesite (PbSO.sub.4) or cerussite (PbCO.sub.3) incorporated into an inert, porous glass matrix via a sol-gel process. Particles of radiation-sensitive scintillant are added to, a sol solution. The mixture is polymerized to form a gel, then dried under conditions that preserve the structural integrity and radiation sensitivity of the scintillant. The final product is a composition containing the uniformly-dispersed scintillant in an inert, optically transparent and highly porous matrix. The composition is chemically inert and substantially impervious to environmental conditions including changes in temperature, air pressure, and so forth. It can be fabricated in cylinders, blocks with holes therethrough for flow of fluid, sheets, surface coatings, pellets or other convenient shapes.

Composition and apparatus for detecting gamma radiation

DOEpatents

Hofstetter, K.J.

1994-08-09

A gamma radiation detector and a radioluminescent composition for use therein. The detector includes a radioluminescent composition that emits light in a characteristic wavelength region when exposed to gamma radiation, and means for detecting said radiation. The composition contains a scintillant such as anglesite (PbSO[sub 4]) or cerussite (PbCO[sub 3]) incorporated into an inert, porous glass matrix via a sol-gel process. Particles of radiation-sensitive scintillant are added to, a sol solution. The mixture is polymerized to form a gel, then dried under conditions that preserve the structural integrity and radiation sensitivity of the scintillant. The final product is a composition containing the uniformly-dispersed scintillant in an inert, optically transparent and highly porous matrix. The composition is chemically inert and substantially impervious to environmental conditions including changes in temperature, air pressure, and so forth. It can be fabricated in cylinders, blocks with holes therethrough for flow of fluid, sheets, surface coatings, pellets or other convenient shapes. 3 figs.

Gynogenesis in carp, Cyprinus Carpio L. and tench, Tinca Tinca L. induced by 60Co radiation in highly homogeneous radiating field

NASA Astrophysics Data System (ADS)

Pipota, J.; Linhart, O.

The paper deals with a method of fertility inactivation of fish spermatozoa by gamma radiation. Spermatozoa motility remained unchanged after irradiation. Irradiated sperm has been utilized to induced gynogenesis by means of retention of the second polar body and of mitotic gynogenesis, realized in carp for the first time. Homogeneity of gamma-rays field was + - 1 %.

Determining optical and radiation characteristics of cathode ray tubes' glass to be reused as radiation shielding glass

NASA Astrophysics Data System (ADS)

Zughbi, A.; Kharita, M. H.; Shehada, A. M.

2017-07-01

A new method of recycling glass of Cathode Ray Tubes (CRTs) has been presented in this paper. The glass from CRTs suggested being used as raw materials for the production of radiation shielding glass. Cathode ray tubes glass contains considerable amounts of environmentally hazardous toxic wastes, namely heavy metal oxides such as lead oxide (PbO). This method makes CRTs glass a favorable choice to be used as raw material for Radiation Shielding Glass and concrete. The heavy metal oxides increase its density, which make this type of glass nearly equivalent to commercially available shielding glass. CRTs glass have been characterized to determine heavy oxides content, density, refractive index, and radiation shielding properties for different Gamma-Ray energies. Empirical methods have been used by using the Gamma-Ray source cobalt-60 and computational method by using the code XCOM. Measured and calculated values were in a good compatibility. The effects of irradiation by gamma rays of cobalt-60 on the optical transparency for each part of the CRTs glass have been studied. The Results had shown that some parts of CRTs glass have more resistant to Gamma radiation than others. The study had shown that the glass of cathode ray tubes could be recycled to be used as radiation shielding glass. This proposed use of CRT glass is only limited to the available quantity of CRT world-wide.

Detecting pin diversion from pressurized water reactors spent fuel assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ham, Young S.; Sitaraman, Shivakumar

Detecting diversion of spent fuel from Pressurized Water Reactors (PWR) by determining possible diversion including the steps of providing a detector cluster containing gamma ray and neutron detectors, inserting the detector cluster containing the gamma ray and neutron detectors into the spent fuel assembly through the guide tube holes in the spent fuel assembly, measuring gamma ray and neutron radiation responses of the gamma ray and neutron detectors in the guide tube holes, processing the gamma ray and neutron radiation responses at the guide tube locations by normalizing them to the maximum value among each set of responses and takingmore » the ratio of the gamma ray and neutron responses at the guide tube locations and normalizing the ratios to the maximum value among them and producing three signatures, gamma, neutron, and gamma-neutron ratio, based on these normalized values, and producing an output that consists of these signatures that can indicate possible diversion of the pins from the spent fuel assembly.« less

Accumulation of Mn(II) in Deinococcus radiodurans Facilitates Gamma-Radiation Resistance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daly, Michael J.; Gaidamakova, E; Matrosova, V

2004-11-05

Deinococcus radiodurans is extremely resistant to ionizing radiation. How this bacterium can grow under chronic gamma-radiation (50 Gy/hour) or recover from acute doses greater than 10 kGy is unknown. We show that D. radiodurans accumulates very high intracellular manganese and low iron levels compared to radiation sensitive bacteria, and resistance exhibits a concentration-dependent response to Mn(II). Among the most radiation-resistant bacterial groups reported, Deinococcus, Enterococcus, Lactobacillus and cyanobacteria spp. accumulate Mn(II). In contrast, Shewanella oneidensis and Pseudomonas putida have high Fe but low intracellular Mn concentrations and are very sensitive. We propose that Mn(II) accumulation facilitates recovery from radiation injury.

Inactivation of foodborne pathogens on crawfish tail meat using cryogenic freezing and gamma radiation

USDA-ARS?s Scientific Manuscript database

Foodborne illness outbreaks occasionally occur as a result of microbiologically contaminated crustaceans, including crawfish. Cryogenic freezing and gamma radiation are two technologies which can be used to improve the microbiological safety and shelf-life of foods. In the U.S. the majority of non-c...

Apparatus and method for the simultaneous detection of neutrons and ionizing electromagnetic radiation

DOEpatents

Bell, Zane W.

2000-01-01

A sensor for simultaneously detecting neutrons and ionizing electromagnetic radiation comprising: a sensor for the detection of gamma radiation, the sensor defining a sensing head; the sensor further defining an output end in communication with the sensing head; and an exterior neutron-sensitive material configured to form around the sensing head; wherein the neutron-sensitive material, subsequent to the capture of the neutron, fissions into an alpha-particle and a .sup.7 Li ion that is in a first excited state in a majority of the fissions, the first excited state decaying via the emission of a single gamma ray at 478 keV which can in turn be detected by the sensing head; and wherein the sensing head can also detect the ionizing electromagnetic radiation from an incident radiation field without significant interference from the neutron-sensitive material. A method for simultaneously detecting neutrons and ionizing electromagnetic radiation comprising the steps of: providing a gamma ray sensitive detector comprising a sensing head and an output end; conforming an exterior neutron-sensitive material configured to form around the sensing head of the detector; capturing neutrons by the sensing head causing the neutron-sensitive material to fission into an alpha-particle and a .sup.7 Li ion that is in a first excited state in a majority of the fissions, the state decaying via the emission of a single gamma ray at 478 keV; sensing gamma rays entering the detector through the neutron-sensitive material; and producing an output through a readout device coupled to the output end; wherein the detector provides an output which is proportional to the energy of the absorbed ionizing electromagnetic radiation.

A Unified Model for GRB Prompt Emission from Optical to Gamma-Rays; Exploring GRBs as Standard Candles

NASA Technical Reports Server (NTRS)

Guiriec, S.; Kouveliotou, C.; Hartmann, D. H.; Granot, J.; Asano, K.; Meszaros, P.; Gill, R.; Gehrels, N.; McEnery, J.

2016-01-01

The origin of prompt emission from gamma-ray bursts (GRBs) remains to be an open question. Correlated prompt optical and gamma-ray emission observed in a handful of GRBs strongly suggests a common emission region, but failure to adequately fit the broadband GRB spectrum prompted the hypothesis of different emission mechanisms for the low- and high-energy radiations. We demonstrate that our multi-component model for GRB -ray prompt emission provides an excellent fit to GRB 110205A from optical to gamma-ray energies. Our results show that the optical and highest gamma-ray emissions have the same spatial and spectral origin, which is different from the bulk of the X- and softest gamma-ray radiation. Finally, our accurate redshift estimate for GRB 110205A demonstrates promise for using GRBs as cosmological standard candles.

Dose response and repair kinetics of gamma-H2AX foci induced by in vitro irradiation of whole blood and T-lymphocytes with X- and gamma-radiation.

PubMed

Beels, Laurence; Werbrouck, Joke; Thierens, Hubert

2010-09-01

Dose response and repair kinetics of phosphorylated histone H2A isoform X (gamma-H2AX) foci in T-lymphocytes were investigated in the low-dose range after in vitro irradiation of whole blood and T-lymphocytes with 100 kVp X-rays and (60)Co gamma-rays. Whole blood or isolated T-lymphocytes were irradiated in vitro and gamma-H2AX foci were scored. Dose response was determined in the 0-500 mGy dose range. Foci kinetics were studied at doses of 5 and 200 mGy up to 24 h post-irradiation. After X-irradiation, the dose response for whole blood shows a biphasic behaviour with a low-dose hypersensitivity, which is less pronounced for isolated T-lymphocytes. In contrast, gamma-radiation shows a linear dose response for both irradiation conditions. Concerning repair kinetics, delayed repair was found after X-ray whole blood irradiation (5 and 200 mGy) with 40% of the foci persisting 24 h post-irradiation. This number of foci is reduced to 10% after irradiation of isolated T-lymphocytes with 200 mGy X-rays. On the contrary, gamma-H2AX foci are reduced to background levels 24 h post-irradiation with 200 mGy (60)Co gamma-rays. gamma-H2AX foci response and repair kinetics depend on irradiation conditions and radiation quality, possibly linked to Bystander response.

Acetylcholine content and cholinesterase activity as related to the combined effects of allergen and radiation. [Rats, gamma radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lipshits, R.U.; Kratinova, M.A.

1977-01-01

Rats were given intraperitoneal injections of antigen and exposed to 200 R of gamma radiation. Acetylcholine content and cholinesterase activity of blood were analyzed every 5 days for 30 days. The interval between sensitization and irradiation determined the direction of changes in allergic reactions. The radiation appreciably attenuated active sensitization of rats. The degree of sensitization was related to changes in cholinergic processes. The data confirmed the assumption that cholinergic systems are involved in the mechanisms of change in allergic reactivity under the influence of radiation. (HLW)

THE DEPRESSANT EFFECT OF CONTINUOUS COBALT-60 RADIATION ON THE SECONDARY TETANUS ANTITOXIN RESPONSE IN MICE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoner, R.D.; Hale, W.M.

1958-05-01

The radiosensitivity of the secondary tetanus antitoxin response in mice was demonstrated after rather low doses of continuous gamma -radiation given at a dose rate of 4 rep/hr. Accumulated doses of 48 to 288 rep depressed antitoxin formation. Comparable doses of acute gamma radiation did not depress antitoxin production. Acute doses of 350 to 650 rep sharply depressed the secondary antibody response, however. Extended periods of continuous gamma -radiation from 10 to 28 days to accumulated doses of 960 to 2688 rep markedly depressed the secondary antibody response. An accumulated dose of 2688 rep was needed to depress antitoxin formationmore » to the level observed after an acute dose of 650 rep. When the secondary stimulus of fluid tetanus toxoid was given prior to 10 days of continuous exposure to an accumulated dose of 860 rep, the secondary antibody respense was not depressed. Irradiated mice recovered the ability to produce a normal secondary antitoxin response during the second week after an accumulated dose of 1248 rep. The secondary antitoxin response was depressed in mice given long-continued gamma -radiation at a dose rate of 1 rep/hr. (auth)« less

Gamma radiation-induced synthesis and characterization of Polyvinylpyrrolidone nanogels

NASA Astrophysics Data System (ADS)

Ges, A. A.; Viltres, H.; Borja, R.; Rapado, M.; Aguilera, Y.

2017-01-01

Due to the importance of bioactive peptides, proteins and drug for pharmaceutical purpose, there is a growing interest for suitable delivery systems, able to increase their bioavailability and to target them to the desired location. Some of the most studied delivery systems involve encapsulation or entrapment of drugs into biocompatible polymeric devices. A multitude of techniques have been described for the synthesis of nanomaterials from polymers, however, the use of ionizing radiation (γ, e-), to obtain nano- and microgels polymer is characterized by the possibility of obtaining products with a high degree of purity. Although, in the world, electronic radiation is used for this purpose, gamma radiation has not been utilized for these purposes. In this paper is developed the formulation the formulation of Polyvinylpyrrolidone (PVP) nanogels synthesized by gamma radiation techniques, for their evaluation as potential system of drug delivery. Experiments were performed in absence of oxygen using aqueous solutions of PVP (0.05% -1%). Crosslinking reactions were carried out at 25° C in a gamma irradiation chamber with a 60Co source (MPX-γ 30). The Viscosimetry, Light Scattering, X-Ray Diffraction and Transmission Electron Microscopy (TEM), were used as characterization techniques.

[The role of homeobox B2 gene in vascular endothelial proliferation and the protective effects of VEGF on the endothelia against radiation injury].

PubMed

Liu, Xu-sheng; Zhang, Xiao-qi; Liu, Liang; Ming, Jia; Xu, Hui; Ran, Xin-ze; Cheng, Tian-min

2004-10-01

To explore the role of HOXB2 gene in the proliferation of primary human umbilical vein endothelial cells (HUVECs) and the protective effects of VEGF on the endothelia against radiation injury. HUVECs were isolated, cultured, subcultured and identified. (1) Liposome coated oligodeoxynucleotide (odn) and homeoboxB2 antisense oligodeoxyncleotide (HOXB2asodn) were prepared prepared in the concentrations of 0.25, 0.5, 1.0 and 2.5 mg/L for the stimulation of HUVEC. (3)H-TdR incorporation test and MTT method were employed to determine the proliferation activity of HUVECs after activation. The cell cycle analysis of HUVECs was determined by flow cytometry. The expression level of HOXB2mRNA within HUVECs was detected by RT-PCR (reverse transcription polymerase chain reaction). (2) HUVECs were separately treated with the addition of VEGF in concentration of 50 microg/L, by radiation in the dose of 6 Gy or 12 Gy (60)Co gamma gamma ray, or radiation with 12 Gy (60)Co gamma gamma ray followed by the addition of VEGF in dose of 50 microg/L. The cellular morphology was observed and the cellular proliferation activity was determined by MTT method. (1) The proliferation activity of HUVECs could be markedly inhibited by liposome coated HOXB2asodn in comparison to liposome-odn (P < 0.05 or 0.001), and the inhibition effect was positively correlated with the increase in asodn concentration. The cell ratio in S phase and the expression level of the HOXB2mRNA could be lowered by asodn in dose of 2.5 mg/L (P < 0.05 or 0.001). (2) Radiation by (60)Co gamma ray could lead to the nuclear enlargement, vacuolation in the cytoplasm, multiplicity of nucleus and nuclear swelling. The proliferative activity of HUVECs was increased from 0.365 +/- 0.047 and 0.487 +/- 0.022 without radiation to 0.557 +/- 0.042 and 0.648 +/- 0.021 24 and 48 hours after 6 Gy radiation However it was decreased to 0.263 +/- 0.038 and 0.306 +/- 0.024 (P < 0.01) after 12 Gy (60)Co gamma ray radiation. Nevertheless, the cell morphology was obviously improved and the proliferation was enhanced by the addition of VEGF after 12 Gy radiation. HOXB2 gene played important roles in the biological activities of HUVECs. Small dose (6 Gy) gamma-radiation could promote, but large dose (12 Gy) could decrease the mRNA expression of HOXB2 gene in HUVECs. In addition, VEGF could protect HUVECs against radiation injury.

Experimental search for radiative decays of the pentaquark baryon {Theta}{sup +}(1540)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barmin, V. V.; Asratyan, A. E.; Borisov, V. S.

2010-07-15

The data on the reactions K{sup +}Xe {sup {yields}}K{sup 0{gamma}}X and K{sup +}Xe {sup {yields}}K{sup +{gamma}}X, obtained with the bubble chamber DIANA, have been analyzed for possible radiative decays of the {Theta}{sup +}(1540) baryon: {Theta}{sup +} {sup {yields}}K{sup 0}p{gamma} and {Theta}{sup +} {sup {yields}}K{sup +}n{gamma}. No signals have been observed, and we derive the upper limits {Gamma}({Theta}{sup +} {sup {yields}}K{sup 0}p{gamma})/{Gamma}({Theta}{sup +} {sup {yields}}K{sup 0}p) < 0.032 and {Gamma}({Theta}{sup +} {sup {yields}}K{sup +}n{gamma})/{Gamma}({Theta}{sup +} {sup {yields}}K{sup +}n{gamma}) < 0.041 which, using our previous measurement of {Gamma}({Theta}{sup +} {sup {yields}}KN) = 0.39 {+-} 0.10 MeV, translate to {Gamma}({Theta}{sup +} {sup {yields}}K{supmore » 0}p{gamma}) < 8 keV and {Gamma}({Theta}{sup +} {sup {yields}}K{sup +}n{gamma}) < 11 keV at 90% confidence level. We have also measured the cross sections of K{sup +}-induced reactions involving emission of a neutral pion: {sigma}(K{sup +}n {sup {yields}}K{sup 0}p{pi}{sup 0}) = 68 {+-} 18 {mu}b and {sigma}(K{sup +}N {sup {yields}}K{sup +}N{pi}{sup 0}) = 30 {+-} 8 {mu}b for incident K{sup +} momentum of 640 MeV.« less

A Monte Carlo simulation to study a design of a gamma-ray detector for neutron resonance densitometry

NASA Astrophysics Data System (ADS)

Tsuchiya, H.; Harada, H.; Koizumi, M.; Kitatani, F.; Takamine, J.; Kureta, M.; Iimura, H.

2013-11-01

Neutron resonance densitometry (NRD) has been proposed to quantify nuclear materials in melted fuel (MF) that will be removed from the Fukushima Daiichi nuclear power plant. The problem is complex due to the expected presence of strong neutron absorbing impurities such as 10B and high radiation field that is mainly caused by 137Cs. To identify the impurities under the high radiation field, NRD is based on a combination of neutron resonance transmission analysis (NRTA) and neutron resonance capture analysis (NRCA). We investigated with Geant4 the performance of a gamma-ray detector for NRCA in NRD. The gamma-ray detector has a well shape, consisting of cylindrical and tube type LaBr3 scintillators. We show how it measures 478 keV gamma rays derived from 10B(n, αγ) reaction in MF under a high 137Cs-radiation environment. It was found that the gamma-ray detector was able to well suppress the Compton edge of 662-keV gamma rays of 137Cs and had a high peak-to-Compton continuum ratio, by using the tube type scintillator as a back-catcher detector. Then, we demonstrate that with this ability, detection of 478-keV gamma rays from 10B is accomplished in realistic measuring time.

Neurogenic Effects of Low-Dose Whole-Body HZE (Fe) Ion and Gamma Irradiation.

PubMed

Sweet, Tara B; Hurley, Sean D; Wu, Michael D; Olschowka, John A; Williams, Jacqueline P; O'Banion, M Kerry

2016-12-01

Understanding the dose-toxicity profile of radiation is critical when evaluating potential health risks associated with natural and man-made sources in our environment. The purpose of this study was to evaluate the effects of low-dose whole-body high-energy charged (HZE) iron (Fe) ions and low-energy gamma exposure on proliferation and differentiation of adult-born neurons within the dentate gyrus of the hippocampus, cells deemed to play a critical role in memory regulation. To determine the dose-response characteristics of the brain to whole-body Fe-ion vs. gamma-radiation exposure, C57BL/6J mice were irradiated with 1 GeV/n Fe ions or a static 137 Cs source (0.662 MeV) at doses ranging from 0 to 300 cGy. The neurogenesis was analyzed at 48 h and one month postirradiation. These experiments revealed that whole-body exposure to either Fe ions or gamma radiation leads to: 1. An acute decrease in cell division within the dentate gyrus of the hippocampus, detected at doses as low as 30 and 100 cGy for Fe ions and gamma radiation, respectively; and 2. A reduction in newly differentiated neurons (DCX immunoreactivity) at one month postirradiation, with significant decreases detected at doses as low as 100 cGy for both Fe ions and gamma rays. The data presented here contribute to our understanding of brain responses to whole-body Fe ions and gamma rays and may help inform health-risk evaluations related to systemic exposure during a medical or radiologic/nuclear event or as a result of prolonged space travel.

High level gamma radiation effects on Cernox™ cryogenic temperature sensors

NASA Astrophysics Data System (ADS)

Courts, S. S.

2017-12-01

Cryogenic temperature sensors are used in high energy particle colliders to monitor the temperatures of superconducting magnets, superconducting RF cavities, and cryogen infrastructure. While not intentional, these components are irradiated by leakage radiation during operation of the collider. A common type of cryogenic thermometer used in these applications is the Cernox™ resistance thermometer (CxRT) manufactured by Lake Shore Cryotronics, Inc. This work examines the radiation-induced calibration offsets on CxRT models CX-1050-SD-HT and CX-1080-SD-HT resulting from exposure to very high levels of gamma radiation. Samples from two different wafers of each of the two models tested were subjected to a gamma radiation dose ranging from 10 kGy to 5 MGy. Data were analysed in terms of the temperature-equivalent resistance change between pre- and post-irradiation calibrations. The data show that the resistance of these devices decreased following irradiation resulting in positive temperature offsets across the 1.4 K to 330 K temperature range. Variations in response were observed between wafers of the same CxRT model. Overall, the offsets increased with increasing temperature and increasing gamma radiation dose. At 1.8 K, the average offset increased from 0 mK to +13 mK as total dose increased from 10 kGy to 5 MGy. At 4.2 K, the average offset increased from +4 mK to +33 mK as total dose increased from 10 kGy to 5 MGy. Equivalent temperature offset data are presented over the 1.4 K to 330 K temperature range by CxRT model, wafer, and total gamma dose.

Comparative study between laser and conventional techniques for class V cavity preparation in gamma-irradiated teeth (in vitro study).

PubMed

Rasmy, Amr H M; Harhash, Tarek A; Ghali, Rami M S; El Maghraby, Eman M F; El Rouby, Dalia H

2017-01-01

The purpose of this study was to compare laser with conventional techniques in class V cavity preparation in gamma-irradiated teeth. Forty extracted human teeth with no carious lesions were used for this study and were divided into two main groups: Group I (n = 20) was not subjected to gamma radiation (control) and Group II (n=20) was subjected to gamma radiation of 60 Gray. Standard class V preparation was performed in buccal and lingual sides of each tooth in both groups. Buccal surfaces were prepared by the Er,Cr:YSGG laser (Waterlase iPlus) 2780 nm, using the gold handpiece with MZ10 Tip in non-contact and the "H" mode, following parameters of cavity preparation - power 6 W, frequency 50 Hz, 90% water and 70% air, then shifting to surface treatment laser parameters - power 4.5 W, frequency 50 Hz, 80% water and 50% air. Lingual surfaces were prepared by the conventional high-speed turbine using round diamond bur. Teeth were then sectioned mesio-distally, resulting in 80 specimens: 40 of which were buccal laser-treated (20 control and 20 gamma-irradiated specimens) and 40 were lingual conventional high-speed bur specimens (20 control and 20 gamma-irradiated specimens). Microleakage analysis revealed higher scores in both gamma groups compared with control groups. Chi-square test revealed no significant difference between both control groups and gamma groups (p=1, 0.819, respectively). A significant difference was revealed between all 4 groups (p=0.00018). Both laser and conventional high-speed turbine bur show good bond strength in control (non-gamma) group, while microleakage is evident in gamma group, indicating that gamma radiation had a dramatic negative effect on the bond strength in both laser and bur-treated teeth.

Gamma ray camera

DOEpatents

Perez-Mendez, V.

1997-01-21

A gamma ray camera is disclosed 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. 6 figs.

Gamma ray camera

DOEpatents

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.

Prompt-gamma monitoring in hadrontherapy: A review

NASA Astrophysics Data System (ADS)

Krimmer, J.; Dauvergne, D.; Létang, J. M.; Testa, É.

2018-01-01

Secondary radiation emission induced by nuclear reactions is correlated to the path of ions in matter. Therefore, such penetrating radiation can be used for in vivo control of hadrontherapy treatments, for which the primary beam is absorbed inside the patient. Among secondary radiations, prompt-gamma rays were proposed for real-time verification of ion range. Such a verification is a desired condition to reduce uncertainties in treatment planning. For more than a decade, efforts have been undertaken worldwide to promote prompt-gamma-based devices to be used in clinical conditions. Dedicated cameras are necessary to overcome the challenges of a broad- and high-energy distribution, a large background, high instantaneous count rates, and compatibility constraints with patient irradiation. Several types of prompt-gamma imaging devices have been proposed, that are either physically-collimated or electronically collimated (Compton cameras). Clinical tests are now undergoing. Meanwhile, other methods than direct prompt-gamma imaging were proposed, that are based on specific counting using either time-of-flight or photon energy measurements. In the present article, we make a review and discuss the state of the art for all techniques using prompt-gamma detection to improve the quality assurance in hadrontherapy.

SYSTEMATIC STUDY OF GAMMA-RAY-BRIGHT BLAZARS WITH OPTICAL POLARIZATION AND GAMMA-RAY VARIABILITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Itoh, Ryosuke; Fukazawa, Yasushi; Kanda, Yuka

Blazars are highly variable active galactic nuclei that 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 2008 July and 2014 December to investigate the mechanisms of variability and search formore » 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), this result implies a systematic difference in the intrinsic alignment of magnetic fields in parsec-scale relativistic jets between different types of blazars (flat-spectrum radio quasars vs. BL Lacs) and consequently between different types of radio galaxies (FR I versus FR II).« less

Neutron-gamma flux and dose calculations for feasibility study of DISCOMS instrumentation in case of severe accident in a GEN 3 reactor

NASA Astrophysics Data System (ADS)

Brovchenko, Mariya; Duhamel, Isabelle; Dechenaux, Benjamin

2017-09-01

The present paper presents the study carried out in the frame of the DISCOMS project, which stands for "DIstributed Sensing for COrium Monitoring and Safety". This study concerns the calculation of the neutron and gamma radiations received by the considered instrumentation during the normal reactor operation as well as in case of a severe accident for the EPR reactor, outside the reactor pressure vessel and in the containment basemat. This paper summarizes the methods and hypotheses used for the particle transport simulation outside the vessel during normal reactor operation. The results of the simulations are then presented including the responses for distributed Optical Fiber Sensors (OFS), such as the gamma dose and the fast neutron fluence, and for Self Powered Neutron Detectors (SPNDs), namely the neutron and gamma spectra. Same responses are also evaluated for severe accident situations in order to design the SPNDs being sensitive to the both types of received neutron-gamma radiation. By contrast, fibers, involved as transducers in distributed OFS have to resist to the total radiation gamma dose and neutron fluence received during normal operation and the severe accident.

Ionizing Organic Compound Based Nanocomposites for Efficient Gamma-Ray Sensor

NASA Technical Reports Server (NTRS)

Singh, N. B.; Dayal, Vishall; Su, Ching-Hua; Arnold, Bradley; Choa, Fow-Sen; Kabandana, Monia G. K.; House, David

2017-01-01

Thin film and nanocrystalline materials of oxides have been very attractive choice as low cost option for gamma-ray detection and have shown great promise. Our studies on pure oxide films indicated that thickness and microstructure have pronounced effect on sensitivity. Since the interaction of gamma-ray with composites involves all three interaction processes; photoelectric effect, Compton scattering, and pair production, composites containing ionic organics have better chance for enhancing sensitivity. In the composites of ionizing organics oxidation effect of unusual oxides changes much faster and hence increases the sensitivity of radiation. In this study, we have used nickel oxide and titanium oxide in ionic organics to develop composite materials for low energy gamma-ray sensing. We prepared composites containing ethylene carbonate and evaluated the effect of commercial Cs-137 radiation source by studying current-voltage relationship at several frequencies. Radiated samples showed higher resistivity compared to as prepared composites.

Radiation shielding composition

DOEpatents

Quapp, W.J.; Lessing, P.A.

1998-07-28

A composition is disclosed for use as a radiation shield. The shield is a concrete product containing a stable uranium aggregate for attenuating gamma rays and a neutron absorbing component, the uranium aggregate and neutron absorbing component being present in the concrete product in sufficient amounts to provide a concrete having a density between about 4 and about 15 grams/cm{sup 3} and which will at a predetermined thickness, attenuate gamma rays and absorb neutrons from a radioactive material of projected gamma ray and neutron emissions over a determined time period. The composition is preferably in the form of a container for storing radioactive materials that emit gamma rays and neutrons. The concrete container preferably comprises a metal liner and/or a metal outer shell. The resulting radiation shielding container has the potential of being structurally sound, stable over a long period of time, and, if desired, readily mobile. 5 figs.

Influence of gamma radiation on the colour strength and fastness properties of fabric using turmeric (Curcuma longa L .) as natural dye

NASA Astrophysics Data System (ADS)

Bhatti, Ijaz A.; Adeel, Shahid; Jamal, M. Asghar; Safdar, Muhammad; Abbas, Muhammad

2010-05-01

The effect of gamma radiation on the dyeing of cotton with extract of turmeric ( Curcuma longa L.) powder has been investigated. Cotton fabric and turmeric powder were irradiated to absorbed doses of 1, 2, 3, 4 and 6 kGy using Co-60 gamma irradiator. Dyeing parameters such as temperature, pH and mordant concentration were optimized. Dyeing was performed using un-irradiated and irradiated cotton with the extracts of un-irradiated and irradiated turmeric powder in order to investigate the effect of radiation treatment on the colour strength of dyed fabric. The reported data of un-irradiated and irradiated fabrics dyed with un-irradiated and irradiated dyes were obtained using the spectraflash SF-650. The colourfastness to light, rubbing- and washing-fastness properties showed that gamma irradiation has improved the dyeing characteristics from fair to good.

Effect of fast neutron, gamma-ray and combined radiations on the thermal decomposition of ammonium perchlorate single crystals

NASA Technical Reports Server (NTRS)

Herley, P. J.; Wang, C. S.; Varsi, G.; Levy, P. W.

1974-01-01

The thermal decomposition kinetics have been determined for ammonium perchlorate crystals subjected to a fast neutron irradiation or to a fast neutron irradiation followed by a gamma-ray irradiation. Qualitatively, the radiation induced changes are similar to those obtained in this and in previous studies, with samples exposed only to gamma rays. The induction period is shortened and the rate constants, obtained from an Avrami-Erofeyev kinetic analysis, are modified. The acceleratory period constant increases and the decay period constant decreases. When compared on an equal deposited energy basis, the fast neutron induced changes are appreciably larger than the gamma-ray induced changes. Some, or all, of the fast neutron induced effects might be attributable to the introduction of localized regions of concentrated radiation damage ('spikes') by lattice atom recoils which become thermal decomposition sites when the crystals are heated.

Detection of gamma-neutron radiation by solid-state scintillation detectors. Detection of gamma-neutron radiation by novel solid-state scintillation detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryzhikov, V.; Grinyov, B.; Piven, L.

It is known that solid-state scintillators can be used for detection of both gamma radiation and neutron flux. In the past, neutron detection efficiencies of such solid-state scintillators did not exceed 5-7%. At the same time it is known that the detection efficiency of the gamma-neutron radiation characteristic of nuclear fissionable materials is by an order of magnitude higher than the efficiency of detection of neutron fluxes alone. Thus, an important objective is the creation of detection systems that are both highly efficient in gamma-neutron detection and also capable of exhibiting high gamma suppression for use in the role ofmore » detection of neutron radiation. In this work, we present the results of our experimental and theoretical studies on the detection efficiency of fast neutrons from a {sup 239}Pu-Be source by the heavy oxide scintillators BGO, GSO, CWO and ZWO, as well as ZnSe(Te, O). The most probable mechanism of fast neutron interaction with nuclei of heavy oxide scintillators is the inelastic scattering (n, n'γ) reaction. In our work, fast neutron detection efficiencies were determined by the method of internal counting of gamma-quanta that emerge in the scintillator from (n, n''γ) reactions on scintillator nuclei with the resulting gamma energies of ∼20-300 keV. The measured efficiency of neutron detection for the scintillation crystals we considered was ∼40-50 %. The present work included a detailed analysis of detection efficiency as a function of detector and area of the working surface, as well as a search for new ways to create larger-sized detectors of lower cost. As a result of our studies, we have found an unusual dependence of fast neutron detection efficiency upon thickness of the oxide scintillators. An explanation for this anomaly may involve the competition of two factors that accompany inelastic scattering on the heavy atomic nuclei. The transformation of the energy spectrum of neutrons involved in the (n, n'γ) reactions towards lower energies and the isotropic character of scattering of the secondary neutrons may lead to the observed limitation of the length of effective interaction, since a fraction of the secondary neutrons that propagate in the forward direction are not subject to further inelastic scattering because of their substantially lower energy. At these reduced energies, it is the capture cross-section (n, γ) that becomes predominant, resulting in lower detection efficiency. Based on these results, several types of detectors have been envisioned for application in detection systems for nuclear materials. The testing results for one such detector are presented in this work. We have studied the possibility of creation of a composite detector with scintillator granules placed inside a transparent polymer material. Because of the low transparency of such a dispersed scintillator, better light collection conditions are ensured by incorporation of a light guide between the scintillator layers. This guide is made of highly transparent polymer material. The use of a high-transparency hydrogen-containing polymer material for light guides not only ensures optimum conditions of light collection in the detector, but also allows certain deceleration of neutron radiation, increasing its interaction efficiency with the composite scintillation panels; accordingly, the detector signal is increased by 5-8%. When fast neutrons interact with the scintillator material, the resulting inelastic scattering gamma-quanta emerge, having different energies and different delay times with respect to the moment of the neutron interaction with the nucleus of the scintillator material (delay times ranging from 1x10{sup -9} to 1.3x10{sup -6} s). These internally generated gamma-quanta interact with the scintillator, and the resulting scintillation light is recorded by the photo-receiver. Since neutron sources are also strong sources of low-energy gamma-radiation, the use of dispersed ZnSe(Te) scintillator material provides high gamma-radiation detection efficiency in that energy range. This new type of gamma-neutron detector is based on a 'sandwich' structure using a ZnSe composite film and light guide with a fast neutron detection efficiency of about 6%. Its high detection efficiency of low-energy gamma-radiation allows a substantial increase (by an order of magnitude) in the efficiency of detection of neutron sources and transuranic materials by means of simultaneous detection of accompanying gamma-radiation. The design and fabrication technology of this detector allows the creation of gamma-neutron detectors characterized by high sensitivity at relatively low costs (as compared with analogs using oxide scintillators) for portable inspection systems. The sandwich structure can be comprised of any number of plates, with no limitations on thickness or area.« less

Eckol protects V79-4 lung fibroblast cells against gamma-ray radiation-induced apoptosis via the scavenging of reactive oxygen species and inhibiting of the c-Jun NH(2)-terminal kinase pathway.

PubMed

Zhang, Rui; Kang, Kyoung Ah; Piao, Mei Jing; Ko, Dong Ok; Wang, Zhi Hong; Lee, In Kyung; Kim, Bum Joon; Jeong, Il Yun; Shin, Taekyun; Park, Jae Woo; Lee, Nam Ho; Hyun, Jin Won

2008-09-04

The radioprotective effect of eckol against gamma-ray radiation-induced oxidative stress and its possible protective mechanisms were investigated. Eckol was found to reduce the intracellular reactive oxygen species generated by gamma-ray radiation. Moreover, eckol also protected against radiation-induced cellular DNA damage and membrane lipid peroxidation, which are the main targets of radiation-induced damage. In addition, eckol recovered the cell viability damaged by radiation via the inhibition of apoptosis. Irradiated cells with eckol treatment reduced the expression of bax, the activation of caspase 9 and caspase 3, which were induced by radiation. However, irradiated cells with eckol recovered the expression of bcl-2 and mitochondrial cytochrome c which were decreased by radiation. The anti-apoptotic effect of eckol exerted via the inhibition of mitogen-activated protein kinase kinase-4 (MKK4/SEK1)-c-Jun NH(2)-terminal kinase (JNK)-activator protein 1 (AP-1) cascades induced by radiation. In summary, the results suggest that eckol protects cells against the oxidative stress induced by radiation via the reduction of reactive oxygen species and the attenuation of activation in SEK1-JNK-AP-1 pathway.

Influence of UV and Gamma radiations on the induced birefringence of stretched poly(vinyl) alcohol foils

NASA Astrophysics Data System (ADS)

Nechifor, Cristina-Delia; Zelinschi, Carmen Beatrice; Dorohoi, Dana-Ortansa

2014-03-01

The aim of our paper is to evidence the influence of Gamma and UV radiations on the induced birefringence of poly(vinyl alcohol) stretched foils. Thin foils of PVA were prepared and dried without modifying their surfaces. The polymeric foils were irradiated from 15 min to 6 h using UV and Gamma radiations. The induced by stretching under heating birefringence of PVA films was measured at λ = 589.3 nm with a Babinet Compensator. Physico-chemical processes (photo stabilization, photo degradation, oxidation) induced by irradiation of polymer matrix influence both the stretching degree and the anisotropy of etired foils. An increase of birefringence versus the stretching ratio of the PVA foils was evidenced for all studied samples. The dependence of the birefringence on the exposure time, stretching ratio and nature of radiation was also confirmed.

Determining a pre-mining radiological baseline from historic airborne gamma surveys: a case study.

PubMed

Bollhöfer, Andreas; Beraldo, Annamarie; Pfitzner, Kirrilly; Esparon, Andrew; Doering, Che

2014-01-15

Knowing the baseline level of radioactivity in areas naturally enriched in radionuclides is important in the uranium mining context to assess radiation doses to humans and the environment both during and after mining. This information is particularly useful in rehabilitation planning and developing closure criteria for uranium mines as only radiation doses additional to the natural background are usually considered 'controllable' for radiation protection purposes. In this case study we have tested whether the method of contemporary groundtruthing of a historic airborne gamma survey could be used to determine the pre-mining radiological conditions at the Ranger mine in northern Australia. The airborne gamma survey was flown in 1976 before mining started and groundtruthed using ground gamma dose rate measurements made between 2007 and 2009 at an undisturbed area naturally enriched in uranium (Anomaly 2) located nearby the Ranger mine. Measurements of (226)Ra soil activity concentration and (222)Rn exhalation flux density at Anomaly 2 were made concurrent with the ground gamma dose rate measurements. Algorithms were developed to upscale the ground gamma data to the same spatial resolution as the historic airborne gamma survey data using a geographic information system, allowing comparison of the datasets. Linear correlation models were developed to estimate the pre-mining gamma dose rates, (226)Ra soil activity concentrations, and (222)Rn exhalation flux densities at selected areas in the greater Ranger region. The modelled levels agreed with measurements made at the Ranger Orebodies 1 and 3 before mining started, and at environmental sites in the region. The conclusion is that our approach can be used to determine baseline radiation levels, and provide a benchmark for rehabilitation of uranium mines or industrial sites where historical airborne gamma survey data are available and an undisturbed radiological analogue exists to groundtruth the data. © 2013.

Anomaly Detection in Gamma-Ray Vehicle Spectra with Principal Components Analysis and Mahalanobis Distances

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tardiff, Mark F.; Runkle, Robert C.; Anderson, K. K.

2006-01-23

The goal of primary radiation monitoring in support of routine screening and emergency response is to detect characteristics in vehicle radiation signatures that indicate the presence of potential threats. Two conceptual approaches to analyzing gamma-ray spectra for threat detection are isotope identification and anomaly detection. While isotope identification is the time-honored method, an emerging technique is anomaly detection that uses benign vehicle gamma ray signatures to define an expectation of the radiation signature for vehicles that do not pose a threat. Newly acquired spectra are then compared to this expectation using statistical criteria that reflect acceptable false alarm rates andmore » probabilities of detection. The gamma-ray spectra analyzed here were collected at a U.S. land Port of Entry (POE) using a NaI-based radiation portal monitor (RPM). The raw data were analyzed to develop a benign vehicle expectation by decimating the original pulse-height channels to 35 energy bins, extracting composite variables via principal components analysis (PCA), and estimating statistically weighted distances from the mean vehicle spectrum with the mahalanobis distance (MD) metric. This paper reviews the methods used to establish the anomaly identification criteria and presents a systematic analysis of the response of the combined PCA and MD algorithm to modeled mono-energetic gamma-ray sources.« less

Important role of catalase in the cellular response of the budding yeast Saccharomyces cerevisiae exposed to ionizing radiation.

PubMed

Nishimoto, Takuto; Furuta, Masakazu; Kataoka, Michihiko; Kishida, Masao

2015-03-01

Ionizing radiation indirectly causes oxidative stress in cells via reactive oxygen species (ROS), such as hydroxyl radicals (OH(-)) generated by the radiolysis of water. We investigated how the catalase function was affected by ionizing radiation and analyzed the phenotype of mutants with a disrupted catalase gene in Saccharomyces cerevisiae exposed to radiation. The wild-type yeast strain and isogenic mutants with disrupted catalase genes were exposed to various doses of (60)Co gamma-rays. There was no difference between the wild-type strain and the cta1 disruption mutant following exposure to gamma-ray irradiation. In contrast, there was a significant decrease in the ctt1 disruption mutant, suggesting that this strain exhibited decreased survival on gamma-ray exposure compared with other strains. In all three strains, stationary phase cells were more tolerant to the exposure of gamma-rays than exponential phase cells, whereas the catalase activity in the wild-type strain and cta1 disruption mutant was higher in the stationary phase than in the exponential phase. These data suggest a correlation between catalase activity and survival following gamma-ray exposure. However, this correlation was not clear in the ctt1 disruption mutant, suggesting that other factors are involved in the tolerance to ROS induced by irradiation.

Use of radiation in biomaterials science

NASA Astrophysics Data System (ADS)

Benson, Roberto S.

2002-05-01

Radiation is widely used in the biomaterials science for surface modification, sterilization and to improve bulk properties. Radiation is also used to design of biochips, and in situ photopolymerizable of bioadhesives. The energy sources most commonly used in the irradiation of biomaterials are high-energy electrons, gamma radiation, ultraviolet (UV) and visible light. Surface modification involves placement of selective chemical moieties on the surface of a material by chemical reactions to improve biointeraction for cell adhesion and proliferation, hemocompatibility and water absorption. The exposure of a polymer to radiation, especially ionizing radiation, can lead to chain scission or crosslinking with changes in bulk and surface properties. Sterilization by irradiation is designed to inactivate most pathogens from the surface of biomedical devices. An overview of the use of gamma and UV radiation to improve surface tissue compatibility, bulk properties and surface properties for wear resistance, formation of hydrogels and curing dental sealants and bone adhesives is presented. Gamma and vacuum ultraviolet (VUV) irradiated ultrahigh molecular weight polyethylene (UHMWPE) exhibit improvement in surface modulus and hardness. The surface modulus and hardness of UHMWPE showed a dependence on type of radiation, dosage and processing. VUV surface modified e-PTFE vascular grafts exhibit increases in hydrophilicity and improvement towards adhesion of fibrin glue.

Effect of gamma ray and high-energy oxygen ion radiation on electrical and optical properties of MCT epitaxial layers

NASA Astrophysics Data System (ADS)

Sitharaman, S.; Kanjilal, D.; Arora, S. K.; Ganguly, S. K.; Nagpal, Anjana; Gautam, Madhukar; Raman, R.; Kumar, Shiv; Prakash, V. R.; Gupta, S. C.

1999-11-01

Hg1-xCdxTe epitaxial layers grown from Te-rich solution have been exposed to Gamma ray radiation up to 650 Grey using Co60 and high energy oxygen radiation at 100Mev. The electrical resistivity, carrier density and Hall mobility values at 77K and IR transmission at 300K have been measured in n,p and compensated epilayers both before and after irradiation. These properties are very much affected by these radiations. In the uncompensated p-type epitaxial layers both types of radiation produced an increase in extrinsic carrier density and a corresponding decrease in Hall mobility. It is observed that both types of radiation have significant effect on the compensated layers and the degree of compensation is greatly reduced by the oxygen irradiation. The 100 Mev oxygen irradiation produced an apparent shift in the bandgap towards shorter wavelength and the absorption below the energy gap is reduced as shown by FTIR measurements, whereas Gamma ray radiation up to the dose 650 Grey did not have any effect on optical properties. These results show the ability of oxygen radiation to passivate the activity of residual impurities or defects.

MICRONUCLEI IN BINUCLEATED LYMPHOCYTES OF MICE FOLLOWING EXPOSURE TO GAMMA RADIATION

EPA Science Inventory

Experiments were designed to investigate the induction of micronuclei (MN) in mouse peripheral blood lymphocytes (PBLs) after in vitro or in vivo exposure to 60Co gamma radiation. or the in vitro experiments, 4 ml of blood from male C57BL/6J mice were either irradiated in 6 ml Fa...

Variable-Temperature Cryostat For Radiation-Damage Testing Of Germanium Detectors

NASA Technical Reports Server (NTRS)

Floyd, Samuel R.; Puc, Bernard P.

1992-01-01

Variable-temperature cryostats developed to study radiation damage to, and annealing of, germanium gamma-ray detectors. Two styles: one accommodates large single detector and one accommodates two medium-sized detectors. New cryostats allow complete testing of large-volume germanium gamma-ray detectors without breaking cryostat vacuum and removing detectors for annealing.

10 CFR 35.690 - Training for use of remote afterloader units, teletherapy units, and gamma stereotactic...

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Training for use of remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.690 Section 35.690 Energy NUCLEAR REGULATORY...) Radiation physics and instrumentation; (B) Radiation protection; (C) Mathematics pertaining to the use and...

10 CFR 35.690 - Training for use of remote afterloader units, teletherapy units, and gamma stereotactic...

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Training for use of remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.690 Section 35.690 Energy NUCLEAR REGULATORY...) Radiation physics and instrumentation; (B) Radiation protection; (C) Mathematics pertaining to the use and...

10 CFR 35.690 - Training for use of remote afterloader units, teletherapy units, and gamma stereotactic...

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Training for use of remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.690 Section 35.690 Energy NUCLEAR REGULATORY...) Radiation physics and instrumentation; (B) Radiation protection; (C) Mathematics pertaining to the use and...

10 CFR 35.690 - Training for use of remote afterloader units, teletherapy units, and gamma stereotactic...

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Training for use of remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.690 Section 35.690 Energy NUCLEAR REGULATORY...) Radiation physics and instrumentation; (B) Radiation protection; (C) Mathematics pertaining to the use and...

Gamma-Ray Attenuation Measurements as a Laboratory Experiment: Some Remarks

ERIC Educational Resources Information Center

Adamides, E.; Koutroubas, S. K.; Moshonas, N.; Yiasemides, K.

2011-01-01

In this article we make some significant remarks on the experimental study of the absorption of gamma radiation passing through matter. These remarks have to do with the seemingly unexpected trend of the measured intensity of radiation versus the thickness of the absorber, which puzzles students and its explanation eludes many laboratory…

Inactivation of Staphylococcus saprophyticus in chicken meat and exudate using high pressure processing, gamma radiation, and ultraviolet light

USDA-ARS?s Scientific Manuscript database

Stapylococcus saprophyticus is a common contaminant in foods and causes urinary tract infections in humans. Three nonthermal food safety intervention technologies used to improve the safety foods include high pressure processing (HPP), ionizing (gamma) radiation (GR), and ultraviolet light (UV-C). A...

Improved detector for the measurement of gamma radiation

NASA Astrophysics Data System (ADS)

Zelt, F. B.

1985-07-01

The present invention lies in the field of gamma ray spectrometry of geologic deposits and other materials, such as building materials (cement, asphalt, etc.) More specifically, the invention is an improved device for the gamma ray spetcrometery of gelogical deposits as a tool for petroleum exploration, geologic research and monitoring of radio-active materials such as in uranium mill tailings and the like. Improvement consists in enlarging the area of the receptor face and without any necessarily substantial increase in the volume of the receptor crystal over the current cylindrical shapes. The invention also provides, as a corollary of the increase in area receptor crystal face, a reduction in the weight of the amount of material necessary to provide effective shielding of the crystal from atmospheric radiation and radiation from deposits not under examination. The area of the receptor crystal face is increased by forming the crystal as a truncated cone with the shielding shaped as a hollow frustrum of a cone. A photomultiplier device is secured to the smaller face of the crystal. The improved detector shape can also be used in scintillometers which measure total gamma radiation.

Impact of gamma radiation on the eruption rate of rat incisors

NASA Astrophysics Data System (ADS)

El-Faramawy, Nabil; El-Haddad, Khaled; Ali, Mohamed; Talaat, Mona

2015-09-01

The present work aims to test the effect of gamma radiation on the rate of eruption of rat incisors. One hundred and five adult male albino rats were used and irradiated at different gamma doses. The effects of irradiation were investigated by numerical measurements of eruption rate, histological investigation using light microscope and spectral analysis using Fourier Transform Infra-Red (FTIR). No detectable changes were observed in the groups with smaller radiation doses. There was a significant decrease in the eruption rate starting from the 4 Gy radiation dose. The observation of histological sections revealed disturbance in cellular elements responsible for eruption as well as periodontal disturbance in the samples irradiated with 4 and 6 Gy. FTIR Spectroscopy of control group and the group irradiated by 0.5 Gy showed similar absorption bands with minor differences. However, samples irradiated by 1 Gy showed significant changes in both molecular structure and conformation related to carbonates and hydroxyl groups. From the previous results, it could be concluded that gamma irradiation negatively affects the eruption rate of the rat incisors especially with higher doses.

Radiation shielding for gamma stereotactic radiosurgery units

PubMed Central

2007-01-01

Shielding calculations for gamma stereotactic radiosurgery units are complicated by the fact that the radiation is highly anisotropic. Shielding design for these devices is unique. Although manufacturers will answer questions about the data that they provide for shielding evaluation, they will not perform calculations for customers. More than 237 such units are now installed in centers worldwide. Centers installing a gamma radiosurgery unit find themselves in the position of having to either invent or reinvent a method for performing shielding design. This paper introduces a rigorous and conservative method for barrier design for gamma stereotactic radiosurgery treatment rooms. This method should be useful to centers planning either to install a new unit or to replace an existing unit. The method described here is consistent with the principles outlined in Report No. 151 from the U.S. National Council on Radiation Protection and Measurements. In as little as 1 hour, a simple electronic spreadsheet can be set up, which will provide radiation levels on planes parallel to the barriers and 0.3 m outside the barriers. PACS numbers: 87.53.Ly, 87.56By, 87.52Tr

Administration of the peroxisomal proliferator-activated receptor {gamma} agonist pioglitazone during fractionated brain irradiation prevents radiation-induced cognitive impairment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao Weiling; Payne, Valerie; Tommasi, Ellen

2007-01-01

Purpose: We hypothesized that administration of the anti-inflammatory peroxisomal proliferator-activated receptor {gamma} (PPAR{gamma}) agonist pioglitazone (Pio) to adult male rats would inhibit radiation-induced cognitive impairment. Methods and Materials: Young adult male F344 rats received one of the following: (1) fractionated whole brain irradiation (WBI); 40 or 45 Gy {gamma}-rays in 4 or 4.5 weeks, respectively, two fractions per week and normal diet; (2) sham-irradiation and normal diet; (3) WBI plus Pio (120 ppm) before, during, and for 4 or 54 weeks postirradiation; (4) sham-irradiation plus Pio; or (5) WBI plus Pio starting 24h after completion of WBI. Results: Administration ofmore » Pio before, during, and for 4 or 54 weeks after WBI prevented Radiation-induced cognitive impairment. Administration of Pio for 54 weeks starting after completion of fractionated WBI substantially but not significantly reduced Radiation-induced cognitive impairment. Conclusions: These findings offer the promise of improving the quality of life and increasing the therapeutic window for brain tumor patients.« less

Investigation of radiosterilization feasibility of sulfamethoxazole by ESR spectroscopy

NASA Astrophysics Data System (ADS)

Çolak, Şeyda

2017-12-01

In the present study, the spectroscopic features of the radiolytic intermediates that were produced in gamma-irradiated (5, 10, 25 and 50 kGy) sulfamethoxazole (SMX) have been investigated by electron spin resonance (ESR) spectroscopy and the radiation sterilization feasibility of SMX by ionizing radiation was examined. Gamma-irradiated SMX exhibited a complex ESR spectrum consisting of 13 resonance lines where spectral parameters for the central resonance line were found to be g = 2.0062 and ΔHpp = 0.6 mT. The radiation yield of SMX was calculated to be relatively low (G = 0.1) by ESR spectroscopy and no meaningful difference was observed in the comparison of unirradiated and 50 kGy gamma irradiated SMX by the Fourier transform infrared (FT-IR) technique, confirming that SMX is a radioresistive material. Although SMX could not be accepted to be a good dosimetric material, the identification of irradiated SMX from the unirradiated sample was possible even for the low absorbed radiation doses and for a relatively long time (three months) after the irradiation process. Decay activation energy of the radical species, which is mostly responsible for the central intense resonance line, is calculated to be 45.15 kJ/mol by using the signal intensity decay data derived from annealing studies. Four radical species with different spectroscopic properties were accepted to be responsible for the ESR spectra of gamma-irradiated SMX, by simulation calculations. It is concluded that SMX and SMX-containing drugs can be sterilized by gamma radiation and ESR spectroscopy is an appropriate technique for the characterization of these induced radical intermediates during the gamma irradiation process of SMX. Toxicology tests should also be done for its safe usage.

Variation in the radon concentrations and outdoor gamma radiation levels in relation to different geological formations in the thermal regions of Bursa, Turkey.

PubMed

Akkaya, Gizem; Kahraman, Ayşegül; Koray, Abdullah; Kaynak, Gökay

2016-09-01

Spring waters used as spas and their region may contain significant amounts of natural radionuclides. The main sources of exposure are the inhalation of radon and its decay products released from the water and soil and terrestrial gamma-radiation. In order to evaluate the potential risk of thermal regions in Bursa, located in the impact area of the NAF (North Anatolian Fault), radon and thoron concentrations in soil gas, radon concentrations in thermal waters and outdoor gamma radiation levels were measured in thermal regions that have different geological formations. The radon and thoron concentrations in soil-gas were found to vary from 2272  ±  121 to 245196  ±  3455 Bq m -3 and from 999  ±  218 to 178 848  ±  17 742 Bq m -3 , respectively. The radon concentrations in thermal waters ranged from 0.99  ±  0.21 to 226.74  ±  2.51 Bq l -1 in the rainy season and from 0.26  ±  0.10 to 178.03  ±  12.86 Bq l -1 in the dry season. The measured outdoor gamma radiation levels varied from 38 to 180 nGy h -1 . The gamma dose rates were found to be strong positively correlating with the radon and thoron concentrations in soil-gas. The radon and outdoor gamma radiation levels were observed to be a function of the geological formations of the area.

Experimental review of light quark spectroscopy from e/sup +/e/sup -/ production and. gamma gamma. collisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toki, W.H.

1987-07-01

This is an experimental review of light quark spectroscopy from e/sup +/e/sup -/ production and ..gamma gamma.. collision results presented at the 2nd International Conference on Hadron Spectroscopy at KEK, Japan. The recent results in ..gamma gamma.. production have evidence for the J/sup PC/ = 1/sup + +/, E/f/sub 1/(1420) and D/f/sub 1/(1285), mesons from the TPC and Mark II collaborations and upper limits for pseudoscalar resonances from the Crystal Ball collaboration. The results in J/psi reactions include D/f/sub 1/(1285) meson production in radiative decays and a complete measurement of the hadronic decays into pseudoscalar-vector pairs from the DM2 collaborationmore » and evidence for phi phi production in radiative decays and a study of the iota line shape from the Mark III collaboration. A short review of simple theoretical ideas is presented.« less

The neutron-gamma Feynman variance to mean approach: Gamma detection and total neutron-gamma detection (theory and practice)

NASA Astrophysics Data System (ADS)

Chernikova, Dina; Axell, Kåre; Avdic, Senada; Pázsit, Imre; Nordlund, Anders; Allard, Stefan

2015-05-01

Two versions of the neutron-gamma variance to mean (Feynman-alpha method or Feynman-Y function) formula for either gamma detection only or total neutron-gamma detection, respectively, are derived and compared in this paper. The new formulas have particular importance for detectors of either gamma photons or detectors sensitive to both neutron and gamma radiation. If applied to a plastic or liquid scintillation detector, the total neutron-gamma detection Feynman-Y expression corresponds to a situation where no discrimination is made between neutrons and gamma particles. The gamma variance to mean formulas are useful when a detector of only gamma radiation is used or when working with a combined neutron-gamma detector at high count rates. The theoretical derivation is based on the Chapman-Kolmogorov equation with the inclusion of general reactions and corresponding intensities for neutrons and gammas, but with the inclusion of prompt reactions only. A one energy group approximation is considered. The comparison of the two different theories is made by using reaction intensities obtained in MCNPX simulations with a simplified geometry for two scintillation detectors and a 252Cf-source. In addition, the variance to mean ratios, neutron, gamma and total neutron-gamma are evaluated experimentally for a weak 252Cf neutron-gamma source, a 137Cs random gamma source and a 22Na correlated gamma source. Due to the focus being on the possibility of using neutron-gamma variance to mean theories for both reactor and safeguards applications, we limited the present study to the general analytical expressions for Feynman-alpha formulas.

Reactivation of Latent Epstein-Barr Virus; A Comparison After Gamma Rays and Proton Treatment

NASA Technical Reports Server (NTRS)

Mehta, Satish K.; Plante, Ianik; Bloom, David C.; Stowe, Raymond; Renner, Ashlie; Wu, Honglu; Crucian, Brian; Pierson, Duane L.

2017-01-01

Among different unique stressors astronauts are exposed to during spaceflight, cosmic radiation constitutes an important one that leads to various health effects. In particular, space radiation may contribute to decreased immunity, which has been observed in astronauts during short and long duration missions, as evidenced by several changes in cellular immunity and plasma cytokines levels. Reactivation of latent herpes viruses, either directly from radiation or resulting from perturbation in the immune system, is also observed in astronauts. While EBV is one of the eight human herpes viruses known to infect more than 90% human adults and stays latent for the life of the host without normally causing adverse effects of reactivation, increased reactivation in astronauts is well-documented, though the mechanism of this increase is not understood. In this work, we have studied the effect of two different types of radiations, Cs-137 gamma and 150-MeV proton on the reactivation rates of the Epstein - Barr virus (EBV) in vitro in EBV latent cell lines at doses of 0.1, 0.5, 1.0 and 2.0 Gy. While we find that both types of radiations reactivated latent EBV in vitro, we observe that at equivalent doses, early response is stronger for protons but with time, the reactivation induced by gamma rays is more persistent. These differences between the protons and gamma rays curves in latent virus reactivation challenge the common paradigm that protons and gamma rays have similar biological effects.

Radiation measurement above the lunar surface by Kaguya gamma-ray spectrometer

NASA Astrophysics Data System (ADS)

Hasebe, Nobuyuki; Nagaoka, Hiroshi; Kusano, Hiroki; Hareyama, Matoko; Ideguchi, Yusuke; Shimizu, Sota; Shibamura, Eido

The lunar surface is filled with various ionizing radiations such as high energy galactic particles, albedo particles and secondary radiations of neutrons, gamma rays and other elementary particles. A high-resolution Kaguya Gamma-Ray Spectrometer (KGRS) was carried on the Japan’s lunar explorer SELENE (Kaguya), the largest lunar orbiter since the Apollo missions. The KGRS instrument employed, for the first time in lunar exploration, a high-purity Ge crystal to increase the identification capability of elemental gamma-ray lines. The Ge detector is surrounded by BGO and plastic counters as for anticoincidence shields. The KGRS measured gamma rays in the energy range from 200 keV to 13 MeV with high precision to determine the chemical composition of the lunar surface. It provided data on the abundance of major elements over the entire lunar surface. In addition to the gamma-ray observation by the KGRS, it successfully measured the global distribution of fast neutrons. In the energy spectra of gamma-rays observed by the KGRS, several saw-tooth- peaks of Ge are included, which are formed by the collision interaction of lunar fast neutrons with Ge atoms in the Ge crystal. With these saw-tooth-peaks analysis, global distribution of neutrons emitted from the lunara surface was successfully created, which was compared with the previous results obtained by Lunar Prospector neutron maps. Another anticoincidence counter, the plastic counter with 5 mm thickness, was used to veto radiation events mostly generated by charged particles. A single photomultiplier serves to count scintillation light from the plastic scintillation counter. The global map of counting rates observed by the plastic counter was also created, implying that the radiation counting rate implies the geological distribution, in spite that the plastic counter mostly measures high energy charged particles and energetic neutrons. These results are presented and discussed.

Papain incorporated chitin dressings for wound debridement sterilized by gamma radiation

NASA Astrophysics Data System (ADS)

Singh, Durgeshwer; Singh, Rita

2012-11-01

Wound debridement is essential for the removal of necrotic or nonviable tissue from the wound surface to create an environment conducive to healing. Nonsurgical enzymatic debridement is an attractive method due to its effectiveness and ease of use. Papain is a proteolytic enzyme derived from the fruit of Carica papaya and is capable of breaking down a variety of necrotic tissue substrates. The present study was focused on the use of gamma radiation for sterilization of papain dressing with wound debriding activity. Membranes with papain were prepared using 0.5% chitin in lithium chloride/dimethylacetamide solvent and sterilized by gamma radiation. Fluid absorption capacity of chitin-papain membranes without glycerol was 14.30±6.57% in 6 h. Incorporation of glycerol resulted in significant (p<0.001) increase in the absorption capacity. Moisture vapour transmission rate of the membranes was 4285.77±455.61 g/m2/24 h at 24 h. Gamma irradiation at 25 kGy was found suitable for sterilization of the dressings. Infrared (IR) spectral scanning has shown that papain was stable on gamma irradiation at 25-35 kGy. The irradiated chitin-papain membranes were impermeable to different bacterial strains and also exhibited strong bactericidal action against both Gram-positive and Gram-negative bacteria. The fluid handling characteristics and the antimicrobial properties of chitin-papain membranes sterilized by gamma radiation were found suitable for use as wound dressing with debriding activity.

Diverse delayed effects in human lymphoblastoid cells surviving exposure to high-LET (56)Fe particles or low-LET (137)Cs gamma radiation

NASA Technical Reports Server (NTRS)

Evans, H. H.; Horng, M. F.; Ricanati, M.; Diaz-Insua, M.; Jordan, R.; Schwartz, J. L.

2001-01-01

To obtain information on the origin of radiation-induced genomic instability, we characterized a total of 166 clones that survived exposure to (56)Fe particles or (137)Cs gamma radiation, isolated approximately 36 generations after exposure, along with their respective control clones. Cytogenetic aberrations, growth alterations, responses to a second irradiation, and mutant frequencies at the Na(+)/K(+) ATPase and thymidine kinase loci were determined. A greater percentage of clones that survived exposure to (56)Fe particles exhibited instability (defined as clones showing one or more outlying characteristics) than in the case of those that survived gamma irradiation. The phenotypes of the unstable clones that survived exposure to (56)Fe particles were also qualitatively different from those of the clones that survived gamma irradiation. A greater percentage (20%) of the unstable clones that survived gamma irradiation than those that survived exposure to (56)Fe particles (4%) showed an altered response to the second irradiation, while an increase in the percentage of clones that had an outlying frequency of ouabain-resistant and thymidine kinase mutants was more evident in the clones exposed to (56)Fe particles than in those exposed to gamma rays. Growth alterations and increases in dicentric chromosomes were found only in clones with more than one alteration. These results underscore the complex nature of genomic instability and the likelihood that radiation-induced genomic instability arises from different original events.

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

NASA Technical Reports Server (NTRS)

Schwarze, G. E.; Frasca, A. J.

1991-01-01

The effects of neutron and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10(exp 13) n/sq cm and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are presented. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed.

GAMMA-RAYS FROM THE QUASAR PKS 1441+25: STORY OF AN ESCAPE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abeysekara, A. U.; Archambault, S.; Archer, A.

2015-12-20

Outbursts from gamma-ray quasars provide insights on the relativistic jets of active galactic nuclei and constraints on the diffuse radiation fields that fill the universe. The detection of significant emission above 100 GeV from a distant quasar would show that some of the radiated gamma-rays escape pair-production interactions with low-energy photons, be it the extragalactic background light (EBL), or the radiation near the supermassive black hole lying at the jet’s base. VERITAS detected gamma-ray emission up to ∼200 GeV from PKS 1441+25 (z = 0.939) during 2015 April, a period of high activity across all wavelengths. This observation of PKS 1441+25more » suggests that the emission region is located thousands of Schwarzschild radii away from the black hole. The gamma-ray detection also sets a stringent upper limit on the near-ultraviolet to near-infrared EBL intensity, suggesting that galaxy surveys have resolved most, if not all, of the sources of the EBL at these wavelengths.« less

The analysis of complex mixed-radiation fields using near real-time imaging.

PubMed

Beaumont, Jonathan; Mellor, Matthew P; Joyce, Malcolm J

2014-10-01

A new mixed-field imaging system has been constructed at Lancaster University using the principles of collimation and back projection to passively locate and assess sources of neutron and gamma-ray radiation. The system was set up at the University of Manchester where three radiation sources: (252)Cf, a lead-shielded (241)Am/Be and a (22)Na source were imaged. Real-time discrimination was used to find the respective components of the neutron and gamma-ray fields detected by a single EJ-301 liquid scintillator, allowing separate images of neutron and gamma-ray emitters to be formed. (252)Cf and (22)Na were successfully observed and located in the gamma-ray image; however, the (241)Am/Be was not seen owing to surrounding lead shielding. The (252)Cf and (241)Am/Be neutron sources were seen clearly in the neutron image, demonstrating the advantage of this mixed-field technique over a gamma-ray-only image where the (241)Am/Be source would have gone undetected. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Gamma watermarking

DOEpatents

Ishikawa, Muriel Y.; Wood, Lowell L.; Lougheed, Ronald W.; Moody, Kenton J.; Wang, Tzu-Fang

2004-05-25

A covert, gamma-ray "signature" is used as a "watermark" for property identification. This new watermarking technology is based on a unique steganographic or "hidden writing" digital signature, implemented in tiny quantities of gamma-ray-emitting radioisotopic material combinations, generally covertly emplaced on or within an object. This digital signature may be readily recovered at distant future times, by placing a sensitive, high energy-resolution gamma-ray detecting instrument reasonably precisely over the location of the watermark, which location may be known only to the object's owner; however, the signature is concealed from all ordinary detection means because its exceedingly low level of activity is obscured by the natural radiation background (including the gamma radiation naturally emanating from the object itself, from cosmic radiation and material surroundings, from human bodies, etc.). The "watermark" is used in object-tagging for establishing object identity, history or ownership. It thus may serve as an aid to law enforcement officials in identifying stolen property and prosecuting theft thereof. Highly effective, potentially very low cost identification-on demand of items of most all types is thus made possible.

Some new results on the frequency characteristics on quartz crystals irradiated by ionizing and particle radiations

NASA Technical Reports Server (NTRS)

Bahadur, H.; Parshad, R.

1981-01-01

The frequency behavior of AT-cut quartz crystals irradiated by X -, gamma rays and fast neutrons. Initial instability in frequency for gamma and neutron irradiated crystals was found. All the different radiations first give a negative frequency shift at lower doses which are followed by positive frequency shift for increased doses. Results are explained in terms of the fundamental crystal structure. Applications of the frequency results for radiation hardening are proposed.

Investigation into the Feasibility of Highly Enriched Uranium Detection by External Neutron Stimulation (Expanded Study)

DTIC Science & Technology

2006-05-01

26 1.10.1 Radiation Isotope Detector Operation ...... 27 1.10.2 HEU Counts in Radioisotope with 1 kg HEU.. 27 1.10.3 Radiation Isotope ...REACTOR GRADE PLUTONIUM ........... 173 10.2 GAMMA EMITTING ISOTOPES IN CARGO MATERIAL ............. 177 10.3 MCNP ANALYSIS OF GAMMA TRANSPORT FROM A...experiment at USNA using a germanium detector .......................... 31 1-13 Counts in the radiation isotope detector versus counting time for 1

Identification of Morphological Character and Esterase Isozyme Pattern in Second-Generation Black Rice Plant Irradiated to Gamma Rays

NASA Astrophysics Data System (ADS)

Hartanti, R. S.; Putri, T. A. N.; Zulfa, F.; Sutarno; Suranto

2017-04-01

Black rice is one of the functional foods due to its high anthocyanin content. Black rice grain was irradiated by gamma rays with a dose of 200 Gy and 300 Gy. The main purpose of this irradiation is to induce mutation to the black rice plant in order to achieve the improved organism. This study was undertaken to elucidate the morphological character and esterase isozyme pattern of black rice plant after irradiated by gamma rays. There were morphological differences on leaves, stems and grains between irradiated and non irradiated black rice plant. Gamma radiation dose of 200 Gy showed the significant influence of the length of the stem, number of internodes, and length of leaves. The radiation dose of 300 Gy showed the significant influence of the decrease value of diameter of 3rd internodes, number of branches and width of leaves. Flowering time is getting faster as increasing radiation dose. At the age of 74 days after planting there are 9.15% plants of 200 Gy radiation dose that have flowered faster than normal plants. This value increased into 11.45% at the dose of radiation 300 Gy. There were differences in the esterase banding pattern between radiation dose of 200 Gy and 300 Gy than the control plants, indicated that randomly mutation has occurred.

Measurement of Cerenkov radiation induced by the gamma-rays of Co-60 therapy units using wavelength shifting fiber.

PubMed

Jang, Kyoung Won; Shin, Sang Hun; Kim, Seon Geun; Kim, Jae Seok; Yoo, Wook Jae; Ji, Young Hoon; Lee, Bongsoo

2014-04-21

In this study, a wavelength shifting fiber that shifts ultra-violet and blue light to green light was employed as a sensor probe of a fiber-optic Cerenkov radiation sensor. In order to characterize Cerenkov radiation generated in the developed wavelength shifting fiber and a plastic optical fiber, spectra and intensities of Cerenkov radiation were measured with a spectrometer. The spectral peaks of light outputs from the wavelength shifting fiber and the plastic optical fiber were measured at wavelengths of 500 and 510 nm, respectively, and the intensity of transmitted light output of the wavelength shifting fiber was 22.2 times higher than that of the plastic optical fiber. Also, electron fluxes and total energy depositions of gamma-ray beams generated from a Co-60 therapy unit were calculated according to water depths using the Monte Carlo N-particle transport code. The relationship between the fluxes of electrons over the Cerenkov threshold energy and the energy depositions of gamma-ray beams from the Co-60 unit is a near-identity function. Finally, percentage depth doses for the gamma-ray beams were obtained using the fiber-optic Cerenkov radiation sensor, and the results were compared with those obtained by an ionization chamber. The average dose difference between the results of the fiber-optic Cerenkov radiation sensor and those of the ionization chamber was about 2.09%.

A biotechnological project with a gamma radiation source of 100,000 Ci

NASA Astrophysics Data System (ADS)

Lombardo, J. H.; Smolko, E. E.

A project for the production of radiovaccines and other bio-medical products is presented which includes a radiation facility provided with a gamma ray source equivalent to 100,000 Ci of Co-60. The whole process incorporates novel basic features in virus production and inactivation steps. The former is carried out in animals previously subjected to immunodepression through electromagnetic radiation. The later is obtained at low temperatures by using either electromagnetic or particle radiations. A vaccine manufacture process is shown to illustrate the utilization of ionizing radiations to obtain a foot and mouth disease virus (FMDV) vaccine with good antigenic quality and low cost.

Critical analysis of active methods of ozone layer recovery

NASA Astrophysics Data System (ADS)

Bekker, S. Z.; Doronin, A. P.; Kozlov, S. I.

2017-09-01

A critical analysis is given for various methods for recovery of the ozone layer of the Earth: the emission of alkane gases, the destruction of freons by laser IR radiation and with microwave discharge, exposure to laser UV radiation and electric discharge in the atmosphere, the use of solar radiation, laser infrared radiation, and gamma rays, and the creation of an artificial formation at high altitudes that shields the solar radiation dissociating ozone. The optimal methods are discussed in terms of their effectiveness, economic costs, and environmental consequences. These include the use of gamma rays sources, electric discharge in the atmosphere, and microwave breakdown.

Radiation lesion to liver DNA of rats exposed to radiation during flight aboard the Kosmos-690 biosatellite. [Effect of weightlessness on. gamma. -radioinduced DNA strand breaks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Komolova, G.S.; Makeeva, V.F.; Egorov, I.A.

1978-10-26

A prime role is attributed to disturbances in DNA structure of nuclear chromatin as the mechanisms of radiation lesions in living cells. For this reason, it may be assumed that a change in the biological effectiveness of radiation delivered to animals under conditions that are extreme for vital functions, including space flight, may occur via modification of radiolesions in chromatin DNA. For this reason, the DNA of rats exposed to radiation from an onboard gamma source in the course of an actual space flight in the Kosmos-690 biosatellite was examined.

Foods for a Mission to Mars: Investigations of Low-Dose Gamma Radiation Effects

NASA Technical Reports Server (NTRS)

Gandolph, J.; Shand, A.; Stoklosa, A.; Ma, A.; Weiss, I.; Alexander, D.; Perchonok, M.; Mauer, L. J.

2007-01-01

Food must be safe, nutritious, and acceptable throughout a long duration mission to maintain the health, well-being, and productivity of the astronauts. In addition to a developing a stable pre-packaged food supply, research is required to better understand the ability to convert edible biomass into safe, nutritious, and acceptable food products in a closed system with many restrictions (mass, volume, power, crew time, etc.). An understanding of how storage conditions encountered in a long-term space mission, such as elevated radiation, will impact food quality is also needed. The focus of this project was to contribute to the development of the highest quality food system possible for the duration of a mission, considering shelf-stable extended shelf-life foods, bulk ingredients, and crops to be grown in space. The impacts of space-relevant radiation doses on food, bulk ingredient, and select candidate crop quality and antioxidant capacity were determined. Interestingly, increasing gamma-radiation doses (0 to 1000 Gy) did not always increase dose-related effects in foods. Intermediate radiation doses (10 to 800Gy) often had significantly larger impact on the stability of bulk ingredient oils than higher (1000Gy) radiation doses. Overall, most food, ingredient, and crop systems investigated showed no significant differences between control samples and those treated with 3 Gy of gamma radiation (the upper limit estimated for a mission to Mars). However, this does not mean that all foods will be stable for 3-5 years, nor does it mean that foods are stable to space radiation comprising more than gamma rays.

Development of an omnidirectional gamma-ray imaging Compton camera for low-radiation-level environmental monitoring

NASA Astrophysics Data System (ADS)

Watanabe, Takara; Enomoto, Ryoji; Muraishi, Hiroshi; Katagiri, Hideaki; Kagaya, Mika; Fukushi, Masahiro; Kano, Daisuke; Satoh, Wataru; Takeda, Tohoru; Tanaka, Manobu M.; Tanaka, Souichi; Uchida, Tomohisa; Wada, Kiyoto; Wakamatsu, Ryo

2018-02-01

We have developed an omnidirectional gamma-ray imaging Compton camera for environmental monitoring at low levels of radiation. The camera consisted of only six CsI(Tl) scintillator cubes of 3.5 cm, each of which was readout by super-bialkali photo-multiplier tubes (PMTs). Our camera enables the visualization of the position of gamma-ray sources in all directions (∼4π sr) over a wide energy range between 300 and 1400 keV. The angular resolution (σ) was found to be ∼11°, which was realized using an image-sharpening technique. A high detection efficiency of 18 cps/(µSv/h) for 511 keV (1.6 cps/MBq at 1 m) was achieved, indicating the capability of this camera to visualize hotspots in areas with low-radiation-level contamination from the order of µSv/h to natural background levels. Our proposed technique can be easily used as a low-radiation-level imaging monitor in radiation control areas, such as medical and accelerator facilities.

Effects of exposure to different types of radiation on behaviors mediated by peripheral or central systems

NASA Technical Reports Server (NTRS)

Rabin, B. M.; Joseph, J. A.; Erat, S.

1998-01-01

The effects of exposure to ionizing radiation on behavior may result from effects on peripheral or on central systems. For behavioral endpoints that are mediated by peripheral systems (e.g., radiation-induced conditioned taste aversion or vomiting), the behavioral effects of exposure to heavy particles (56Fe, 600 MeV/n) are qualitatively similar to the effects of exposure to gamma radiation (60Co) and to fission spectrum neutrons. For these endpoints, the only differences between the different types of radiation are in terms of relative behavioral effectiveness. For behavioral endpoints that are mediated by central systems (e.g., amphetamine-induced taste aversion learning), the effects of exposure to 56Fe particles are not seen following exposure to lower LET gamma rays or fission spectrum neutrons. These results indicate that the effects of exposure to heavy particles on behavioral endpoints cannot necessarily be extrapolated from studies using gamma rays, but require the use of heavy particles.

Fermi Gamma-Ray Observatory-Science Highlights for the First 8 Months

NASA Technical Reports Server (NTRS)

Moiseev, Alexander

2009-01-01

This viewgraph presentation reviews the science highlights for the first 8 months of the Fermi Gamma-Ray Observatory. Results from pulsars, flaring AGN, gamma ray bursts, diffuse radiation, LMC and electron spectrum are also presented.

The structure and content of the galaxy and galactic gamma rays

NASA Technical Reports Server (NTRS)

Fichtel, C. E. (Editor); Stecker, F. W. (Editor)

1977-01-01

Gamma radiation investigations by COS-B and SAS-2 satellite are reported. Data from CO surveys of the galaxy and the galactic distribution of pulsars are analyzed. Theories of galactic gamma ray emission are explored.

Gamma radiation effects on polydimethylsiloxane rubber foams under different radiation conditions

NASA Astrophysics Data System (ADS)

Sui, H. L.; Liu, X. Y.; Zhong, F. C.; Li, X. Y.; Wang, L.; Ju, X.

2013-07-01

Polydimethylsiloxane rubber foams were irradiated by gamma ray under different radiation conditions designed by orthogonal design method. Compression set measurement, infrared attenuated total reflectance spectroscopy (ATR) and X-ray induced photoelectron spectroscopy (XPS) were used. Three aging factors' influence effects on the mechanical property and chemical structure were studied. It was found that among the three factors and the chosen levels, both properties were affected most by radiation dose, while radiation dose rate had no obvious influence on both properties. The stiffening of the rubber foams was caused by cross-linking reactions in the Si-CH3. At the same radiation dose, the rigidity of the foams irradiated in air was lower than that in nitrogen. When polydimethylsiloxane was irradiated at a high dose in sealed nitrogen atmosphere, carbon element distribution would be changed. Hydrocarbons produced by gamma ray in the sealed tube would make the carbon content in the skin-deep higher than that in the middle, which indicated that polydimethylsiloxane rubber foams storing in a sealed atmosphere filled with enough hydrocarbons should be helpful to extend the service life.

Effect of ionizing radiation on some quality attributes of nutraceutically valued lotus seeds.

PubMed

Bhat, Rajeev; Karim, A A

2009-01-01

Radiation processing has been employed successfully for value addition of food and agricultural products. Preliminary studies were undertaken to evaluate the changes induced by ionizing radiation (up to 30 kGy), in the form of gamma irradiation and electron beam irradiation, on some quality attributes and nutritive values of nutraceutically valued lotus seeds. Significant loss in seed firmness was recorded between control and irradiated seeds, irrespective of radiation source. Similarly, the specific viscosity of irradiated lotus seeds decreased significantly up to a dose of 7.5 kGy. Starch increased after exposure to gamma or electron beam irradiation, whereas the total phenolic contents were decreased. Gamma irradiation revealed an enhancement in protein, while the electron beam showed a decrease. Partial oxidation of the seeds during radiation treatments might have occurred as evidenced from the decomposition profiles (thermogravimetry) during heating. It is evident that ionizing radiation brought about significant and variable changes in the quality and nutritive values of lotus seed. Further exploration of this technology for safety and quality is warranted.

Mutant quantity and quality in mammalian cells (AL) exposed to cesium-137 gamma radiation: effect of caffeine

NASA Technical Reports Server (NTRS)

McGuinness, S. M.; Shibuya, M. L.; Ueno, A. M.; Vannais, D. B.; Waldren, C. A.; Chatterjee, A. (Principal Investigator)

1995-01-01

We examined the effect of caffeine (1,3,7-trimethylxanthine) on the quantity and quality of mutations in cultured mammalian AL human-hamster hybrid cells exposed to 137Cs gamma radiation. At a dose (1.5 mg/ml for 16 h) that reduced the plating efficiency (PE) by 20%, caffeine was not itself a significant mutagen, but it increased by approximately twofold the slope of the dose-response curve for induction of S1- mutants by 137Cs gamma radiation. Molecular analysis of 235 S1- mutants using a series of DNA probes mapped to the human chromosome 11 in the AL hybrid cells revealed that 73 to 85% of the mutations in unexposed cells and in cells treated with caffeine alone, 137Cs gamma rays alone or 137Cs gamma rays plus caffeine were large deletions involving millions of base pairs of DNA. Most of these deletions were contiguous with the region of the MIC1 gene at 11p13 that encodes the S1 cell surface antigen. In other mutants that had suffered multiple marker loss, the deletions were intermittent along chromosome 11. These "complex" mutations were rare for 137Cs gamma irradiation (1/63 = 1.5%) but relatively prevalent (23-50%) for other exposure conditions. Thus caffeine appears to alter both the quantity and quality of mutations induced by 137Cs gamma irradiation.

Detection of DNA Damage by Space Radiation in Human Fibroblasts Flown on the International Space Station

NASA Technical Reports Server (NTRS)

Lu, Tao; Zhang, Ye; Wong, Michael; Feiveson, Alan; Gaza, Ramona; Stoffle, Nicholas; Wang, Huichen; Wilson, Bobby; Rohde, Larry; Stodieck, Louis;

Neurogenic Effects of Low-Dose Whole-Body HZE (Fe) Ion and Gamma Irradiation

PubMed Central

Sweet, Tara B.; Hurley, Sean D.; Wu, Michael D.; Olschowka, John A.; Williams, Jacqueline P.; O’Banion, M. Kerry

2017-01-01

Understanding the dose-toxicity profile of radiation is critical when evaluating potential health risks associated with natural and man-made sources in our environment. The purpose of this study was to evaluate the effects of low-dose whole-body high-energy charged (HZE) iron (Fe) ions and low-energy gamma exposure on proliferation and differentiation of adult-born neurons within the dentate gyrus of the hippocampus, cells deemed to play a critical role in memory regulation. To determine the dose-response characteristics of the brain to whole-body Fe-ion vs. gamma-radiation exposure, C57BL/6J mice were irradiated with 1 GeV/n Fe ions or a static 137Cs source (0.662 MeV) at doses ranging from 0 to 300 cGy. The neurogenesis was analyzed at 48 h and one month postirradiation. These experiments revealed that whole-body exposure to either Fe ions or gamma radiation leads to: 1. An acute decrease in cell division within the dentate gyrus of the hippocampus, detected at doses as low as 30 and 100 cGy for Fe ions and gamma radiation, respectively; and 2. A reduction in newly differentiated neurons (DCX immunoreactivity) at one month postirradiation, with significant decreases detected at doses as low as 100 cGy for both Fe ions and gamma rays. The data presented here contribute to our understanding of brain responses to whole-body Fe ions and gamma rays and may help inform health-risk evaluations related to systemic exposure during a medical or radiologic/nuclear event or as a result of prolonged space travel. PMID:27905869

Gamma radiation exposure of accompanying persons due to Lu-177 patients

NASA Astrophysics Data System (ADS)

Kovan, Bilal; Demir, Bayram; Tuncman, Duygu; Capali, Veli; Turkmen, Cuneyt

2015-07-01

Neuroendocrine tumours (NET) are cancers usually observed and arisen in the stomach, intestine, pancreas and breathing system. Recently, radionuclide therapy applications with Lu-177 peptide compound are rapidly growing; especially effective clinical results are obtained in the treatment of well-differentiated and metastatic NET. In this treatment, Lu-177-DOTA, a beta emitter radioisotope in the radiopharmaceutical form, is given to the patient by intravenous way. Lu-177 has also gamma rays apart from beta rays. Gamma rays have 175 keV average energy and these gamma rays should be under the control in terms of radiation protection. In this study, we measured the exposure dose from the Lu-177 patient.

Effect of gamma irradiation on curcuminoids and volatile oils of fresh turmeric ( Curcuma longa)

NASA Astrophysics Data System (ADS)

Dhanya, R.; Mishra, B. B.; Khaleel, K. M.

2011-11-01

In our earlier study a radiation dose of 5 kGy was reported to be suitable for microbial decontamination and shelf life extension of fresh turmeric ( Curcuma longa), while maintaining its quality attributes. In continuation of that work, the effect of gamma radiation on curcuminoids and volatile oil constituents in fresh turmeric was studied. Fresh peeled turmeric rhizomes were gamma irradiated at doses of 1, 3 and 5 kGy. Curcuminoid content and volatile oils were analyzed by reverse phase HPLC and GC-MS, respectively. The curcuminoid content was slightly increased by gamma irradiation. No statistically significant changes were observed due to irradiation in majority of the volatile oil constituents.

Possible protective effect of the algae spirulina against nephrotoxicity induced by cyclosporine A and/or gamma radiation in rats.

PubMed

Aziz, Maha M; Eid, Nihad I; Nada, Ahmed S; Amin, Nour El-Din; Ain-Shoka, Afaf A

2018-03-01

The present study was conducted to evaluate the possible protective role of the algae spirulina (Sp) against nephrotoxicity and oxidative stress which are the main secondary effects induced by the immunosuppressant drug CSA and/or ionizing radiation. In this study, male rats were given Sp (1 g/kg) either for 15 days before irradiation (6.5 Gy) or 5 days before and 10 days concomitant with CSA (25 mg/kg). Markers used to assess renal injury included serum creatinine, urea, glucose, albumin, protein, and lipid profile as well as kidney content of reduced glutathione (GSH); lipid peroxidation (thiobarbituric acid reactive substances (TBARS)); nitrite and superoxide dismutase (SOD) activity. In addition, some trace elements (Zn and Mg) were estimated in kidney. Apoptosis was assessed by immunohistochemical estimation of caspase-3 expression in addition to histopathological examination. Results revealed that gamma radiation and/or CSA induced elevation in urea, creatinine, lipids, and glucose while decreasing albumin and protein levels. There was a noticeable increase in kidney content of GSH, TBARS, and nitrite. Meanwhile, profound decrease in kidney SOD activity was observed. Treatment with Sp significantly reversed the changes induced by CSA and/or gamma radiation in renal function tests. Spirulina also ameliorated kidney oxidative stress through decreasing GSH, TBARS, and nitrite kidney content while increasing SOD activity. Histopathological examination further confirmed Sp protective efficacy. Moreover, kidney caspase-3 expression that was triggered by CSA and/or gamma radiation was decreased. In conclusion, spirulina can be regarded as a promising renoprotective natural agent against renal injury induced by CSA and/or gamma radiation.

Analyzing the dose-dependence of the Saccharomyces cerevisiae global transcriptional response to methyl methanesulfonate and ionizing radiation.

PubMed

Benton, Michael G; Somasundaram, Swetha; Glasner, Jeremy D; Palecek, Sean P

2006-12-01

One of the most crucial tasks for a cell to ensure its long term survival is preserving the integrity of its genetic heritage via maintenance of DNA structure and sequence. While the DNA damage response in the yeast Saccharomyces cerevisiae, a model eukaryotic organism, has been extensively studied, much remains to be elucidated about how the organism senses and responds to different types and doses of DNA damage. We have measured the global transcriptional response of S. cerevisiae to multiple doses of two representative DNA damaging agents, methyl methanesulfonate (MMS) and gamma radiation. Hierarchical clustering of genes with a statistically significant change in transcription illustrated the differences in the cellular responses to MMS and gamma radiation. Overall, MMS produced a larger transcriptional response than gamma radiation, and many of the genes modulated in response to MMS are involved in protein and translational regulation. Several clusters of coregulated genes whose responses varied with DNA damaging agent dose were identified. Perhaps the most interesting cluster contained four genes exhibiting biphasic induction in response to MMS dose. All of the genes (DUN1, RNR2, RNR4, and HUG1) are involved in the Mec1p kinase pathway known to respond to MMS, presumably due to stalled DNA replication forks. The biphasic responses of these genes suggest that the pathway is induced at lower levels as MMS dose increases. The genes in this cluster with a threefold or greater transcriptional response to gamma radiation all showed an increased induction with increasing gamma radiation dosage. Analyzing genome-wide transcriptional changes to multiple doses of external stresses enabled the identification of cellular responses that are modulated by magnitude of the stress, providing insights into how a cell deals with genotoxicity.

Organic liquid scintillation detectors for on-the-fly neutron/gamma alarming and radionuclide identification in a pedestrian radiation portal monitor

NASA Astrophysics Data System (ADS)

Paff, Marc Gerrit; Ruch, Marc L.; Poitrasson-Riviere, Alexis; Sagadevan, Athena; Clarke, Shaun D.; Pozzi, Sara

2015-07-01

We present new experimental results from a radiation portal monitor based on the use of organic liquid scintillators. The system was tested as part of a 3He-free radiation portal monitor testing campaign at the European Commission's Joint Research Centre in Ispra, Italy, in February 2014. The radiation portal monitor was subjected to a wide range of test conditions described in ANSI N42.35, including a variety of gamma-ray sources and a 20,000 n/s 252Cf source. A false alarm test tested whether radiation portal monitors ever alarmed in the presence of only natural background. The University of Michigan Detection for Nuclear Nonproliferation Group's system triggered zero false alarms in 2739 trials. It consistently alarmed on a variety of gamma-ray sources travelling at 1.2 m/s at a 70 cm source to detector distance. The neutron source was detected at speeds up to 3 m/s and in configurations with up to 8 cm of high density polyethylene shielding. The success of on-the-fly radionuclide identification varied with the gamma-ray source measured as well as with which of two radionuclide identification methods was used. Both methods used a least squares comparison between the measured pulse height distributions to library spectra to pick the best match. The methods varied in how the pulse height distributions were modified prior to the least squares comparison. Correct identification rates were as high as 100% for highly enriched uranium, but as low as 50% for 241Am. Both radionuclide identification algorithms produced mixed results, but the concept of using liquid scintillation detectors for gamma-ray and neutron alarming in radiation portal monitor was validated.

Immunofluorescent Detection of DNA Double Strand Breaks induced by High-LET Radiation

NASA Technical Reports Server (NTRS)

Cucinotta, Francis A.; Wu, Honglu; Desai, Nirav

2004-01-01

Within cell nuclei, traversing charged heavy ion particles lead to the accumulation of proteins related to DNA lesions and repair along the ion trajectories. Irradiation using a standard geometric setup with the beam path perpendicular to the cell monolayer generates discrete foci of several proteins known to localize at sites of DNA double strand breaks (DSBs). One such molecule is the histone protein H2AX (gamma-H2AX), which gets rapidly phosphorylated in response to ionizing radiation. Here we present data obtained with a modified irradiation geometry characterized by a beam path parallel to a monolayer of human fibroblast cells. This new irradiation geometry leads to the formation of gamma-H2AX aggregates in the shape of streaks stretching over several micrometers in the x/y plane, thus enabling the analysis of the fluorescence distributions along the particle trajectories. Qualitative analysis of these distributions presented insights into the DNA repair kinetics along the primary track structure and visualization of possible chromatin movement. We also present evidence of colocalization of gamma-H2AX with several other proteins in responses to ionizing radiation exposure. Analysis of gamma-H2AX has the potential to provide useful information on human cell responses to high LET radiation after exposure to space-like radiation.

Measurement of energetic radiation caused by thunderstorm activities by a sounding balloon and ground observation

NASA Astrophysics Data System (ADS)

Torii, T.

2015-12-01

Energetic radiation caused by thunderstorm activity is observed at various places, such as the ground, high mountain areas, and artificial satellites. In order to investigate the radiation source and its energy distribution, we measured energetic radiation by a sounding balloon, and the ground observation. On the measurement inside/above the thundercloud, we conducted a sounding observation using a radiosonde mounted two GM tubes (for gamma-rays, and for beta/gamma-rays), in addition to meteorological instruments. The balloon passed through a region of strong echoes in a thundercloud shown by radar image, at which time an increase in counting rate of the GM tube about 2 orders of magnitude occurred at the altitude from 5 km to 7.5 km. Furthermore, the counting rate of two GM tubes indicated the tendency different depending on movement of a balloon. This result suggests that the ratio for the gamma-rays (energetic photons) of the beta-rays (energetic electrons) varies according to the place in the thundercloud. Furthermore, we carried out a ground observation of the energetic gamma rays during winter thunderstorm at a coastal area facing the Sea of Japan. Two types of the energetic radiation have been observed at this time. We report the outline of these measurements and analysis in the session of the AGU meeting.

Sewage sludge pasteurization by gamma radiation: Financial viability case studies

NASA Astrophysics Data System (ADS)

Swinwood, Jean F.; Kotler, Jiri

This paper examines the financial viability of sewage sludge pasteurization by gamma radiation, by examining the following three North American scenarios: 1) Small volume sewage treatment plant experiencing high sludge disposal costs. 2) Large volume sewage treatment plant experiencing low sludge disposal costs. 3) Large volume sewage treatment plant experiencing high sludge disposal costs.

Nickel(II) affects poly(ADP-ribose) polymerase-mediated DNA repair in normal and cancer cells.

PubMed

Wozniak, Katarzyna; Czechowska, Agnieszka; Blasiak, Janusz

2006-01-01

Nickel(II) can be genotoxic, but the mechanism of its genotoxicity is not fully understood and the process of DNA repair may be considered as its potential target. We studied the effect of nickel chloride on the poly(ADP-ribose) polymerase (PARP)-mediated repair of DNA damaged by gamma-radiation and idarubicin with the alkaline comet assay in normal and cancer cells. Our results indicate that nickel chloride at very low, non-cytotoxic concentration of 1 microM can affect PARP-mediated DNA repair of lesions evoked by idarubicin and gamma-radiation. We also suggest that in the quiescent lymphocytes treated with gamma-radiation, nickel(II) could interfere with DNA repair process independent of PARP.

Apparatus and methods for determining gas saturation and porosity of a formation penetrated by a gas filled or liquid filled borehole

DOEpatents

Wilson, Robert D.

2001-03-27

Methods and apparatus are disclosed for determining gas saturation, liquid saturation, porosity and density of earth formations penetrated by a well borehole. Determinations are made from measures of fast neutron and inelastic scatter gamma radiation induced by a pulsed, fast neutron source. The system preferably uses two detectors axially spaced from the neutron source. One detector is preferably a scintillation detector responsive to gamma radiation, and a second detector is preferably an organic scintillator responsive to both neutron and gamma radiation. The system can be operated in cased boreholes which are filled with either gas or liquid. Techniques for correcting all measurements for borehole conditions are disclosed.

Treatment of mice with sepsis following irradiation and trauma with antibiotics and synthetic trehalose dicorynomycolate (S-TDCM). (Reannouncement with new availability information)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Madonna, G.S.; Ledney, G.D.; Moore, M.M.

Compromise of antimicrobial defenses by irradiation can result in sepsis and death. Additional trauma can further predispose patients to infection and thus increase mortality. The authors recently showed that injection of synthetic trehalose dicorynomycolate (S-TDCM) significantly augments resistance to infection and increases survival of mice compromised either by whole-body irradiation with gamma radiation or equal mixtures of fission neutron and gamma radiation. In this study, C3H/HeN mice were given a lethal dose of gamma radiation (8.0 Gy) and an open wound (15% total body surface area TBSA) 1 hr later while anesthetized. Irradiated/wounded mice became more severely leukopenic and thrombocytopenicmore » than mice exposed to radiation alone. However, this treatment did not increase survival of the irradiated/wounded mice.« less

Gamma-irradiated bacterial preparation having anti-tumor activity

DOEpatents

Vass, Arpad A.; Tyndall, Richard L.; Terzaghi-Howe, Peggy

1999-01-01

A bacterial preparation from Pseudomonas species isolated #15 ATCC 55638 that has been exposed to gamma radiation exhibits cytotoxicity that is specific for neoplastic carcinoma cells. A method for obtaining a bacterial preparation having antitumor activity consists of suspending a bacterial isolate in media and exposing the suspension to gamma radiation. A bacterial preparation of an aged culture of an amoeba-associated bacteria exhibits anti-reverse transcriptase activity. A method for obtaining a bacterial preparation having anti-reverse transcriptase activity from an amoeba-associated bacterial isolate grown to stationary phase is disclosed.

High-efficiency scintillation detector for combined detection of thermal and fast neutrons and gamma radiation

DOEpatents

Chiles, M.M.; Mihalczo, J.T.; Blakeman, E.D.

1987-02-27

A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation event count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

High-efficiency scintillation detector for combined of thermal and fast neutrons and gamma radiation

DOEpatents

Chiles, Marion M.; Mihalczo, John T.; Blakeman, Edward D.

1989-02-07

A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation even count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

High-efficiency scintillation detector for combined of thermal and fast neutrons and gamma radiation

DOEpatents

Chiles, Marion M.; Mihalczo, John T.; Blakeman, Edward D.

1989-01-01

A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation even count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

Dose-dependent analysis of acute medical effects of mixed neutron-gamma radiation from selected severe 235U or 239Pu criticality accidents in USSR, United States, and Argentina.

PubMed

Barabanova, Tatyana; Wiley, Albert L; Bushmanov, Andrey

2012-04-01

Eight of the most severe cases of acute radiation disease (ARS) known to have occurred in humans (as the result of criticality accidents) had survival times less than 120 h (herein defined as "early death"). These accidents were analyzed and are discussed with respect to the specific accident scenarios and the resulting accident-specific, mixed neutron-gamma radiation clinical dose distributions. This analysis concludes that the cardiovascular system appears to be the most critical organ system failure for causing "early death" following approximate total body, mixed gamma-neutron radiation doses greater than 40-50 Gy. The clinical data also suggest that there was definite chest dose dependence in the resulting survival times for these eight workers, who unfortunately suffered profound radiation injury and unusual clinical effects from such high dose radiation exposures. In addition, "toxemic syndrome" is correlated with the irradiation of large volumes of soft tissues. Doses to the hands or legs greater than 80-100 Gy or radiation lung injury also play significant but secondary roles in causing "early death" in accidents delivering chest doses greater than 50 Gy.

Combined Effects of Gamma Radiation and High Dietary Iron on Peripheral Leukocyte Distribution and Function

NASA Technical Reports Server (NTRS)

Crucian, Brian E.; Morgan, Jennifer L. L.; Quiriarte, Heather A.; Sams, Clarence F.; Smith, Scott M.; Zwart, Sara R.

2012-01-01

Both radiation and increased iron stores can independently increase oxidative damage, resulting in protein, lipid and DNA oxidation. Oxidative stress increases the risk of many health problems including cancer, cataracts, and heart disease. This study, a subset of a larger interdisciplinary investigation of the combined effect of iron overload on sensitivity to radiation injury, monitored immune parameters in the peripheral blood of rats subjected to gamma radiation, high dietary iron or both. Specific immune measures consisted of: (1) peripheral leukocyte distribution, (2) plasma cytokine levels and (3) cytokine production profiles following whole blood mitogenic stimulation

The diffuse galactic gamma radiation: The Compton contribution and component separation by energy interval and galactic coordinates

NASA Technical Reports Server (NTRS)

Kniffen, D. A.; Fichtel, C.

1981-01-01

The radiation to be expected from cosmic ray interactions with matter and photons was examined. Particular emphasis is placed on the Compton emission. Both the photon density in and near the visible region and that in the region are deduced from the estimates of the emission functions throughout the Galaxy. The blackbody radiation is also included in the estimate of the total Compton emission. The result suggests that the gamma ray Compton radiation from cosmic ray ineractions with galactic visible and infrared photons is substantially larger than previously believed.

RADIATION SOURCES

DOEpatents

Brucer, M.H.

1958-04-15

A novel long-lived source of gamma radiation especially suitable for calibration purposes is described. The source of gamma radiation is denoted mock iodine131, which comprises a naixture of barium-133 and cesium-137. The barium and cesium are present in a barium-cesium ratio of approximately 5.7/1 to 14/1, uniformly dispersed in an ion exchange resin and a filter surrounding the resin comprised of a material of atomic number below approximately 51, and substantially 0.7 to 0.9 millimeter thick.

Use of gamma radiation for preparation of nutrient culture media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Speranskaya, I.D.; Tumanyan, M.A.; Mironova, L.L.

1977-01-01

A technique was developed for sterilization of nutrient culture media using ..gamma..-radiation. For this purpose, dry preparations were exposed to 3 to 6 Mrad radiation, then dissolved in sterile distilled water. The quality of media and solutions thus obtained is as good as that of preparations sterilized by filtration. The advantage of the proposed sterilization method is that liquid media can be rapidly prepared and dry sterile media can be stored at room temperature for long periods of time.

Radiation hardness of β-Ga2O3 metal-oxide-semiconductor field-effect transistors against gamma-ray irradiation

NASA Astrophysics Data System (ADS)

Wong, Man Hoi; Takeyama, Akinori; Makino, Takahiro; Ohshima, Takeshi; Sasaki, Kohei; Kuramata, Akito; Yamakoshi, Shigenobu; Higashiwaki, Masataka

2018-01-01

The effects of ionizing radiation on β-Ga2O3 metal-oxide-semiconductor field-effect transistors (MOSFETs) were investigated. A gamma-ray tolerance as high as 1.6 MGy(SiO2) was demonstrated for the bulk Ga2O3 channel by virtue of weak radiation effects on the MOSFETs' output current and threshold voltage. The MOSFETs remained functional with insignificant hysteresis in their transfer characteristics after exposure to the maximum cumulative dose. Despite the intrinsic radiation hardness of Ga2O3, radiation-induced gate leakage and drain current dispersion ascribed respectively to dielectric damage and interface charge trapping were found to limit the overall radiation hardness of these devices.

Mercuric iodine room temperature gamma-ray detectors

NASA Technical Reports Server (NTRS)

Patt, Bradley E.; Markakis, Jeffrey M.; Gerrish, Vernon M.; Haymes, Robert C.; Trombka, Jacob I.

1990-01-01

high resolution mercuric iodide room temperature gamma-ray detectors have excellent potential as an essential component of space instruments to be used for high energy astrophysics. Mercuric iodide detectors are being developed both as photodetectors used in combination with scintillation crystals to detect gamma-rays, and as direct gamma-ray detectors. These detectors are highly radiation damage resistant. The list of applications includes gamma-ray burst detection, gamma-ray line astronomy, solar flare studies, and elemental analysis.

1H NMR Metabolomics Study of Spleen from C57BL/6 Mice Exposed to Gamma Radiation

PubMed Central

Xiao, X; Hu, M; Liu, M; Hu, JZ

2016-01-01

Due to the potential risk of accidental exposure to gamma radiation, it’s critical to identify the biomarkers of radiation exposed creatures. In the present study, NMR based metabolomics combined with multivariate data analysis to evaluate the metabolites changed in the C57BL/6 mouse spleen after 4 days whole body exposure to 3.0 Gy and 7.8 Gy gamma radiations. Principal component analysis (PCA) and orthogonal projection to latent structures analysis (OPLS) are employed for classification and identification potential biomarkers associated with gamma irradiation. Two different strategies for NMR spectral data reduction (i.e., spectral binning and spectral deconvolution) are combined with normalize to constant sum and unit weight before multivariate data analysis, respectively. The combination of spectral deconvolution and normalization to unit weight is the best way for identifying discriminatory metabolites between the irradiation and control groups. Normalized to the constant sum may achieve some pseudo biomarkers. PCA and OPLS results shown that the exposed groups can be well separated from the control group. Leucine, 2-aminobutyrate, valine, lactate, arginine, glutathione, 2-oxoglutarate, creatine, tyrosine, phenylalanine, π-methylhistidine, taurine, myoinositol, glycerol and uracil are significantly elevated while ADP is decreased significantly. These significantly changed metabolites are associated with multiple metabolic pathways and may be potential biomarkers in the spleen exposed to gamma irradiation. PMID:27019763

Radiological survey results at Building 22, Washington Navy Yard, Washington, D.C. (WNS001)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodriguez, R.E.; Foley, R.D.; Uziel, M.S.

A radiological survey was conducted in a portion of Building 22 at the Washington Navy Yard, Washington, D.C., on December 13, 1995. The survey was performed because former employees thought the area surveyed had some previous association with radioactive material. Employees remembered seeing radiation signs in the area and indicated that personnel occupying this area wore dosimeters. Two rooms in the survey area were surrounded by 1-ft-thick poured concrete walls and similar 6-in.-thick ceilings, and situated on top of a 1-ft-thick concrete slab, a configuration commonly used for radiation shielding in industrial radiography facilities. The radiological survey showed no gamma,more » beta-gamma, or alpha measurements above typical background levels. Low background radiation levels within the building indicated that even if low-level contamination were present beneath the tile, or larger amounts of contamination beneath the concrete slab, it poses no radiological hazard to building inhabitants under the present conditions. Further investigation may be required before drilling or demolition of the concrete slab. No photon radiation fields from sealed gamma sources or x-ray sources were detectable at the time of the survey. Gamma spectrometry analysis revealed no gamma emitters above typical background concentrations in one sediment and one water sample collected from a pit in the open bay area.« less

1H NMR metabolomics study of spleen from C57BL/6 mice exposed to gamma radiation

DOE PAGES

Xiao, Xiongjie; Hu, M.; Liu, M.; ...

2016-01-27

Due to the potential risk of accidental exposure to gamma radiation, it’s critical to identify the biomarkers of radiation exposed creatures. In the present study, NMR based metabolomics combined with multivariate data analysis to evaluate the metabolites changed in the C57BL/6 mouse spleen after 4 days whole body exposure to 3.0 Gy and 7.8 Gy gamma radiations. Principal component analysis (PCA) and orthogonal projection to latent structures analysis (OPLS) are employed for classification and identification potential biomarkers associated with gamma irradiation. Two different strategies for NMR spectral data reduction (i.e., spectral binning and spectral deconvolution) are combined with normalize tomore » constant sum and unit weight before multivariate data analysis, respectively. The combination of spectral deconvolution and normalization to unit weight is the best way for identifying discriminatory metabolites between the irradiation and control groups. Normalized to the constant sum may achieve some pseudo biomarkers. PCA and OPLS results shown that the exposed groups can be well separated from the control group. Leucine, 2-aminobutyrate, valine, lactate, arginine, glutathione, 2-oxoglutarate, creatine, tyrosine, phenylalanine, π-methylhistidine, taurine, myoinositol, glycerol and uracil are significantly elevated while ADP is decreased significantly. As a result, these significantly changed metabolites are associated with multiple metabolic pathways and may be potential biomarkers in the spleen exposed to gamma irradiation.« less

Increased Radioresistance to Lethal Doses of Gamma Rays in Mice and Rats after Exposure to Microwave Radiation Emitted by a GSM Mobile Phone Simulator

PubMed Central

Mortazavi, SMJ; Mosleh-Shirazi, MA; Tavassoli, AR; Taheri, M; Mehdizadeh, AR; Namazi, SAS; Jamali, A; Ghalandari, R; Bonyadi, S; Haghani, M; Shafie, M

2013-01-01

The aim of this study was to investigate the effect of pre-irradiation with microwaves on the induction of radioadaptive response. In the 1st phase of the study, 110 male mice were divided into 8 groups. The animals in these groups were exposed/sham-exposed to microwave, low dose rate gamma or both for 5 days. On day six, the animals were exposed to a lethal dose (LD). In the 2nd phase, 30 male rats were divided into 2 groups of 15 animals. The 1st group received microwave exposure. The 2nd group (controls) received the same LD but there was no treatment before the LD. On day 5, all animals were whole-body irradiated with the LD. Statistically significant differences between the survival rate of the mice only exposed to lethal dose of gamma radiation before irradiation with a lethal dose of gamma radiation with those of the animals pre-exposed to either microwave (p=0.02), low dose rate gamma (p=0.001) or both of these physical adapting doses (p=0.003) were observed. Likewise, a statistically significant difference between survival rates of the rats in control and test groups was observed. Altogether, these experiments showed that exposure to microwave radiation may induce a significant survival adaptive response. PMID:23930107

Naturally induced secondary radiation in interplanetary space: Preliminary analyses for gamma radiation and radioisotope production from thermal neutron activation

NASA Technical Reports Server (NTRS)

Plaza-Rosado, Heriberto

1991-01-01

Thermal neutron activation analyses were carried out for various space systems components to determine gamma radiation dose rates and food radiation contamination levels. The space systems components selected were those for which previous radiation studies existed. These include manned space vehicle radiation shielding, liquid hydrogen propellant tanks for a Mars mission, and a food supply used as space vehicle radiation shielding. The computational method used is based on the fast neutron distribution generated by the BRYNTRN and HZETRN transport codes for Galactic Cosmic Rays (GCR) at solar minimum conditions and intense solar flares in space systems components. The gamma dose rates for soft tissue are calculated for water and aluminum space vehicle slab shields considering volumetric source self-attenuation and exponential buildup factors. In the case of the lunar habitat with regolith shielding, a completely exposed spherical habitat was assumed for mathematical convenience and conservative calculations. Activation analysis of the food supply used as radiation shielding is presented for four selected nutrients: potassium, calcium, sodium, and phosphorus. Radioactive isotopes that could represent a health hazard if ingested are identified and their concentrations are identified. For nutrients soluble in water, it was found that all induced radioactivity was below the accepted maximum permissible concentrations.

Naturally induced secondary radiation in interplanetary space: Preliminary analyses for gamma radiation and radioisotope production from thermal neutron activation

NASA Astrophysics Data System (ADS)

Plaza-Rosado, Heriberto

1991-09-01

Thermal neutron activation analyses were carried out for various space systems components to determine gamma radiation dose rates and food radiation contamination levels. The space systems components selected were those for which previous radiation studies existed. These include manned space vehicle radiation shielding, liquid hydrogen propellant tanks for a Mars mission, and a food supply used as space vehicle radiation shielding. The computational method used is based on the fast neutron distribution generated by the BRYNTRN and HZETRN transport codes for Galactic Cosmic Rays (GCR) at solar minimum conditions and intense solar flares in space systems components. The gamma dose rates for soft tissue are calculated for water and aluminum space vehicle slab shields considering volumetric source self-attenuation and exponential buildup factors. In the case of the lunar habitat with regolith shielding, a completely exposed spherical habitat was assumed for mathematical convenience and conservative calculations. Activation analysis of the food supply used as radiation shielding is presented for four selected nutrients: potassium, calcium, sodium, and phosphorus. Radioactive isotopes that could represent a health hazard if ingested are identified and their concentrations are identified. For nutrients soluble in water, it was found that all induced radioactivity was below the accepted maximum permissible concentrations.

Gross morphometric reduction of rats' cerebellum by gamma irradiation was mitigated by pretreatment with Vernonia amygdalina leaf extract.

PubMed

Owoeye, O; Farombi, E O; Onwuka, S K

2011-01-01

The methanolic extract of Vernonia amygdalina (M) or "bitter leaf" is known for its antioxidant activity, and antioxidants are noted to mitigate radiation damage in tissues. The aim of the present study was to observe the radioprotective effect of M on the cerebellum of gamma irradiated rats using alpha-tocopherol (TOCO) as a reference antioxidant. Forty-two male Wistar rats (n=42) weighing 200-240 g were taken for the study. The study comprised of seven groups, with each group comprising of six (n=6) rats i.e. control, M at 250, and 500 mg/kg/day, radiation only, radiation plus M at 250, and 500 mg/kg/day, and TOCO. After 14 days of treatment administered via oral gavage, rats were irradiated with a single dose of 2.0 Gy of gamma rays on the 15-th day and euthanized the next day. Rats cerebella were removed, fixed in 10% formalin saline, weighed and vernier caliper used to obtain cerebellar dimensions as follows: (i) maximum width, (ii) rostrocaudal dimension, and (iii) dorsoventral extent. Data were analyzed using ANOVA with post-test. Gamma radiation caused a statistically significant reduction of the relative weight of the rats' whole brain, relative weight of the cerebellum, the maximum width, rostrocaudal dimension, and dorsoventral extent of the cerebellum. However, pretreatment with M and TOCO significantly mitigated these effects. This study demonstrated that administration of M and TOCO before 2.0 Gy gamma irradiation reduced significantly the radiation induced gross morphometry changes in rats' cerebellum, suggesting that M may qualify for consideration as a medicinal radioprotector.

Comparative toxicity and micronuclei formation in Tribolium castaneum, Callosobruchus maculatus and Sitophilus oryzae exposed to high doses of gamma radiation.

PubMed

Ahmadi, Mehrdad; Mozdarani, Hossein; Abd-Alla, Adly M M

2015-07-01

The effects of gamma radiation on mortality and micronucleus formation in Tribolium castaneum Herbst, Callosobruchus maculatus (F.) and Sitophilus oryzae (L.) genital cells were evaluated. Two groups of healthy and active adult insects 1-3 and 8-10 days old were irradiated with various doses (50-200 Gy) gamma ray. Seven days post-irradiation; mortality rates and micronucleus formation were assessed in genital cells of the irradiated insects. The results show that with increasing gamma doses, the mortality rate of each species increased and T. castaneum and S. oryzae showed the low and high sensitivity respectively. It was shown that the micronucleus appearance in the tested insects had correlation with amount and intensity of radiation doses. Moreover our results indicate different levels in the genotoxicity of gamma radiation among the insects' genital cells under study. The frequency of micronuclei in genital cells of 1-3 days old insects exposed to 50 and 200 Gy were 12.6 and 38.8 Mn/1000 cells in T. castaneum, 20.8 and 46.8 Mn/1000 cells in C. maculatus and 16.8 and 57.2 Mn/1000 cells in S. oryzae respectively. A high sensitivity of the genital cells to irradiation exposure was seen in S. oryzae correlated with its high mortality rate compared with the other two species. These results might be indicative of inflicting chromosomal damage expressed as micronucleus in high mortality rates observed in the pest population; an indication of genotoxic effects of radiation on the studied species. Copyright © 2015 Elsevier Ltd. All rights reserved.

Application of gamma radiation for the reduction of norovirus and the quality stability in optimally ripened cabbage kimchi.

PubMed

Park, Shin Young; Ha, Sang-Do

2017-10-01

Optimally ripened commercial cabbage kimchi is considered the main cause of enteric norovirus (NoV) outbreaks in Korea. This study investigated the effect of 1-10kGy gamma radiation on the inactivation of murine norovirus-1 (MNV-1; initial inoculum of 5-6log 10 PFU/ml), used as a human NoV surrogate, in kimchi. The effects of gamma radiation on the pH and acidity were also examined to address the index of quality and fermentation, respectively. Titers of MNV-1 significantly reduced (p<0.05) in kimchi subjected to increasing gamma radiation doses: MNV-1 titers in kimchi after 1, 3, 5, 7, and 10kGy were 4.82 (0.34-log 10 reduction), 4.45 (0.71-log 10 reduction), 4.18 (0.98-log 10 reduction), 3.71 (1.45-log 10 reduction), and 3.40 (1.76-log 10 reduction) log 10 PFU/ml, respectively. However, the values of pH (4.5-4.6) and acidity (0.6-0.7%) were not significantly different between non-irradiated and irradiated kimchi (p>0.05). The D-value (1-log reduction) for MNV-1 in kimchi, calculated using first-order kinetics, was 5.75kGy (R 2 =0.98, RMSE=0.10). Therefore, this study suggests that the use of ≥5.75kGy gamma radiation in the kimchi manufacturing industry could be very effective in reducing NoV contamination by >90% (1 log), without causing changes in quality and fermentation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Portable compton gamma-ray detection system

DOEpatents

Rowland, Mark S [Alamo, CA; Oldaker, Mark E [Pleasanton, CA

2008-03-04

A Compton scattered gamma-ray detector system. The system comprises a gamma-ray spectrometer and an annular array of individual scintillators. The scintillators are positioned so that they are arrayed around the gamma-ray spectrometer. The annular array of individual scintillators includes a first scintillator. A radiation shield is positioned around the first scintillator. A multi-channel analyzer is operatively connected to the gamma-ray spectrometer and the annular array of individual scintillators.

Confirmatory radiological survey of the BORAX-V turbine building Idaho National Engineering Laboratory, Idaho Falls, Idaho

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stevens, G.H.; Coleman, R.L.; Jensen, M.K.

1993-07-01

An independent assessment of the remediation of the BORAX-V (Boiling Water Reactor Experiment) turbine building at the Idaho National Engineering Laboratory (INEL), Idaho Falls, Idaho, was accomplished by the Oak Ridge National Laboratory Pollutant Assessments Group (ORNL/PAG). The purpose of the assessment was to confirm the site`s compliance with applicable Department of Energy guidelines. The assessment included reviews of both the decontamination and decommissioning Plan and data provided from the pre- and post-remedial action surveys and an independent verification survey of the facility. The independent verification survey included determination of background exposure rates and soil concentrations, beta-gamma and gamma radiationmore » scans, smears for detection of removable contamination, and direct measurements for alpha and beta-gamma radiation activity on the basement and mezzanine floors and the building`s interior and exterior walls. Soil samples were taken, and beta-gamma and gamma radiation exposure rates were measured on areas adjacent to the building. Results of measurements on building surfaces at this facility were within established contamination guidelines except for elevated beta-gamma radiation levels located on three isolated areas of the basement floor. Following remediation of these areas, ORNL/PAG reviewed the remedial action contractor`s report and agreed that remediation was effective in removing the source of the elevated direct radiation. Results of all independent soil analyses for {sup 60}Co were below the detection limit. The highest {sup 137}Cs analysis result was 4.6 pCi/g; this value is below the INEL site-specific guideline of 10 pCi/g.« less

System for inspecting large size structural components

DOEpatents

Birks, Albert S.; Skorpik, James R.

1990-01-01

The present invention relates to a system for inspecting large scale structural components such as concrete walls or the like. The system includes a mobile gamma radiation source and a mobile gamma radiation detector. The source and detector are constructed and arranged for simultaneous movement along parallel paths in alignment with one another on opposite sides of a structural component being inspected. A control system provides signals which coordinate the movements of the source and detector and receives and records the radiation level data developed by the detector as a function of source and detector positions. The radiation level data is then analyzed to identify areas containing defects corresponding to unexpected variations in the radiation levels detected.

Fourier Transform IR Spectroscopic Study of Nano-ZrO2 + Nano-SiO2 + Nano-H2O Systems Upon the Action of Gamma Radiation

NASA Astrophysics Data System (ADS)

Agayev, T. N.; Gadzhieva, N. N.; Melikova, S. Z.

2018-05-01

The radiation decomposition of water in a nano-ZrO2 + nano-SiO2 + H2O system at 300 K by the action of gamma radiation has been studied by Fourier transform IR spectroscopy. Water adsorption in the zirconium and silicon nanooxides is attributed to molecular and dissociative mechanisms. Active intermediates in this radiation-induced heterogeneous decomposition of water were detected including zirconium and silicon hydrides and hydroxyl groups. Variation in the ratio of ZrO2 and SiO2 nanopowders was shown to lead to change in their radiation catalytic activity compared to initial ZrO2.

Fiber optic Cerenkov radiation sensor system to estimate burn-up of spent fuel: characteristic evaluation of the system using Co-60 source

NASA Astrophysics Data System (ADS)

Shin, S. H.; Jang, K. W.; Jeon, D.; Hong, S.; Kim, S. G.; Sim, H. I.; Yoo, W. J.; Park, B. G.; Lee, B.

2013-09-01

Cerenkov radiation occurs when charged particles are moving faster than the speed of light in a transparent dielectric medium. In optical fibers, the Cerenkov light also can be generated due to their dielectric components. Accordingly, the radiation-induced light signals can be obtained using optical fibers without any scintillating material. In this study, to measure the intensities of Cerenkov radiation induced by gamma-rays, we have fabricated the fiber-optic Cerenkov radiation sensor system using silica optical fibers, plastic optical fibers, multi-anode photomultiplier tubes, and a scanning system. To characterize the Cerenkov radiation generated in optical fibers, the spectra of Cerenkov radiation generated in the silica and plastic optical fibers were measured. Also, the intensities of Cerenkov radiation induced by gamma-rays generated from a cylindrical Co-60 source with or without lead shielding were measured using the fiberoptic Cerenkov radiation sensor system.

Antimicrobial activity of silver nanoparticles synthesized using honey and gamma radiation against silver-resistant bacteria from wounds and burns

NASA Astrophysics Data System (ADS)

Hosny, A. M. S.; Kashef, M. T.; Rasmy, S. A.; Aboul-Magd, D. S.; El-Bazza, Z. E.

2017-12-01

Silver nanoparticles (AgNPs) are promising antimicrobial agents for treatment of wounds and burns. We synthesized AgNPs using honey at different pH values or with different gamma irradiation doses. The resulting nanoparticles were characterized by UV-vis spectroscopy, TEM, DLS and FTIR. Their antimicrobial activity, against standard bacterial strains and silver-resistant clinical isolates from infected wounds and burns, was evaluated in vitro through determination of their minimum inhibitory concentration (MIC). AgNPs prepared using 30 g of honey exposed to 5 kGy gamma radiation had the best physical characters regarding stability and uniformity of particle size and shape. They recorded the lowest MIC values against both the standard and silver-resistant isolates. In conclusion, honey and gamma radiation can be used in synthesis of highly stable pure AgNPs, without affecting the physico-chemical and antimicrobial activity of honey. This offered an advantage in terms of inhibition of silver-resistant bacteria isolates.

Radiation resistance of a gamma-ray irradiated nonlinear optic chromophore

NASA Astrophysics Data System (ADS)

Zhang, Cheng; Taylor, Edward W.

2009-11-01

The radiation resistance of organic electro-optic and optoelectronic materials for space applications is receiving increased attention. An earlier investigation reported that guest-host poled polymer EO modulator devices composed of a phenyltetraene bridge-type chromophore in amorphous polycarbonate (CLD/APC) did not exhibit a decrease in EO response (i.e., an increase in modulation-switching voltage- Vπ) following irradiation by low dose [10-160 krad(Si)] 60Co gamma-rays. To provide further evidences to the observed radiation stability, the post-irradiation responses of 60Co gamma-rays on CLD1/APC thin films are examined by various chemical and spectroscopic methods including: a solubility test, thin-layer chromatography, proton nuclear magnetic resonance spectroscopy, UV-vis absorption, and infra-red absorption. The results indicate that CLD1 and APC did not decompose under gamma-ray irradiation at dose levels ranging from 66-274 krad(Si) and from 61-154 krad(Si), respectively which support the previously reported data.

Studies on production of fructo-oligosaccharides (FOS) by gamma radiation processing of microbial levan.

PubMed

Jalan, N; Varshney, Lalit; Misra, Nilanjal; Paul, Jhimli; Mitra, D; Rairakhwada, D D; Bhathena, Z; Kumar, Virendra

2013-07-01

Microbial levan, a natural polymer of fructose, was produced and purified by alcohol precipitation from culture supernatants of Bacillus megaterium type 1 grown in an optimized liquid sucrose medium. GPC analysis showed that the yield of the major fraction of levan having molecular weight ~5000 D increased with increase in sucrose concentration in the broth. Levan subjected to (60)Co-gamma radiation as well as acid hydrolysis was investigated by rheometry, UV-visible spectrophotometry and gel permeation chromatography (GPC) techniques. Unlike most of the polysaccharides, levan powder exhibited good radiation degradation stability up to 150 kGy. Gamma irradiation of 10% levan aqueous solution at 250 kGy yielded 63.0% fructo-oligosaccharide (FOS) with an average molecular weight of 1250 D. Acid hydrolysis of levan using 0.5 N HCl for 60 min treatment time gave rise to the desired FOS with lower yield (23.1%) as compared to that obtained in gamma radiolysis process. Copyright © 2013 Elsevier Ltd. All rights reserved.

Involvement of DNA-PK(sub cs) in DSB Repair Following Fe-56 Ion Irradiation

NASA Technical Reports Server (NTRS)

O'Neill, Peter; Harper, Jane; Anderson, Jennifer a.; Cucinnota, Francis A.

2007-01-01

When cells are exposed to radiation, cellular lesions are induced in the DNA including double strand breaks (DSBs), single strand breaks and clustered DNA damage, which if not repaired with high fidelity may lead to detrimental biological consequences. Complex DSBs are induced by ionizing radiation and characterized by the presence of base lesions close to the break termini. They are believed to be one of the major causes of the biological effects of IR. The complexity of DSBs increases with the ionization density of the radiation and these complex DSBs are distinct from the damage induced by sparsely ionizing gamma-radiation. It has been hypothesized that complex DSBs produced by heavy ions in space pose problems to the DNA repair machinery. We have used imm uno-cyto-chemical staining of phosphorylated histone H2AX (gamma-H2AX) foci, as a marker of DSBs. We have investigated the formation and loss of gamma-H2AX foci and RAD51 foci (a protein involved in the homologous recombination pathway) in mammalian cells induced by low fluences of low-LET gamma-radiation and high-LET Fe-56 ions (1GeV/n, 151 keV/micron LET). M059J and M059K cells, which are deficient and proficient in DNA-PK(sub cs) activity respectively, were used to examine the role of DNA-PK(sub cs), a key protein in the non-homologous end joining (NHEJ) pathway of DSB repair, along with HF19 human fibroblasts. Followi ng irradiation with Fe-56 ions the rate of repair was slower in M059J cells compared with that in M059K, indicating a role for DNA-PK(sub cs) in the repair of DSB induced by Fe-56 ions. However a small percentage of DSBs induced are rejoined within 5 h although many DSBs still persist up to 24 h. When RAD51 was examined in M059J/K cells, RAD51 foci are visible 24 hours after irradiation in approximately 40% of M059J cells compared with <5% of M059K cells indicating that persistent DSBs or those formed at stalled replication forks recruit RAD51 in DNA-PK(sub cs) deficient cells. Following 1 Gy gamma-radiation the induction of gamma-H2AX foci is similar in M059J and M059K cells. However, the repair rate of DSBs is slower in M059J cells than in M059K as shown previously but faster than seen with DSB induced by 56Fe ions. Vanillin, an inhibitor of DNA-PK(sub cs), reduces significantly the rate of DSB repair in HF19 cells following 1 Gy gamma-radiation but at 0.25 Gy gamma-irradiation the rate of DSB repair is similar in the presence or absence vanillin, thus suggesting the repair of a sub-set of DSBs induced by low dose, low-LET radiation does not require DNA-PK(sub cs). This sub-set of DSBs is formed in lower yield with high LET radiation. T he complexity of DNA DSBs induced by HZE radiation will be discussed in terms of reduced repair efficiency and provide scope to model different sub-classes of DSBs as precursors that may lead to the detrimental health effects of HZE radiation.

Kinetic study of radiation-reaction-limited particle acceleration during the relaxation of unstable force-free equilibria

DOE PAGES

Yuan, Yajie; Nalewajko, Krzysztof; Zrake, Jonathan; ...

2016-09-07

Many powerful and variable gamma-ray sources, including pulsar wind nebulae, active galactic nuclei and gamma-ray bursts, seem capable of accelerating particles to gamma-ray emitting energies efficiently over very short timescales. These are likely due to the rapid dissipation of electromagnetic energy in a highly magnetized, relativistic plasma. In order to understand the generic features of such processes, we have investigated simple models based on the relaxation of unstable force-free magnetostatic equilibria. In this work, we make the connection between the corresponding plasma dynamics and the expected radiation signal, using 2D particle-in-cell simulations that self-consistently include synchrotron radiation reactions. We focusmore » on the lowest order unstable force-free equilibrium in a 2D periodic box. We find that rapid variability, with modest apparent radiation efficiency as perceived by a fixed observer, can be produced during the evolution of the instability. The "flares" are accompanied by an increased polarization degree in the high energy band, with rapid variation in the polarization angle. Furthermore, the separation between the acceleration sites and the synchrotron radiation sites for the highest energy particles facilitates acceleration beyond the synchrotron radiation reaction limit. We also discuss the dynamical consequences of the radiation reaction, and some astrophysical applications of this model. Our current simulations with numerically tractable parameters are not yet able to reproduce the most dramatic gamma-ray flares, e.g., from the Crab Nebula. As a result, higher magnetization studies are promising and will be carried out in the future.« less

Selective Shielding of Bone Marrow: An Approach to Protecting Humans from External Gamma Radiation.

PubMed

Waterman, Gideon; Kase, Kenneth; Orion, Itzhak; Broisman, Andrey; Milstein, Oren

2017-09-01

The current feasibility of protecting emergency responders through bone marrow selective shielding is highlighted in the recent OECD/NEA report on severe accident management. Until recently, there was no effective personal protection from externally penetrating gamma radiation. In Chernobyl, first-responders wore makeshift lead sheeting, whereas in Fukushima protective equipment from gamma radiation was not available. Older protective solutions that use thin layers of shielding over large body surfaces are ineffective for energetic gamma radiation. Acute exposures may result in Acute Radiation Syndrome where the survival-limiting factor up to 10 Gy uniform, homogeneous exposure is irreversible bone marrow damage. Protracted, lower exposures may result in malignancies of which bone marrow is especially susceptible, being compounded by leukemia's short latency time. This highlights the importance of shielding bone marrow for preventing both deterministic and stochastic effects. Due to the extraordinary regenerative potential of hematopoietic stem cells, to effectively prevent the deterministic effects of bone marrow exposure, it is sufficient to protect only a small fraction of this tissue. This biological principle allows for a new class of equipment providing unprecedented attenuation of radiation to select marrow-rich regions, deferring the hematopoietic sub-syndrome of Acute Radiation Syndrome to much higher doses. As approximately half of the body's active bone marrow resides within the pelvis region, shielding this area holds great promise for preventing the deterministic effects of bone marrow exposure and concomitantly reducing stochastic effects. The efficacy of a device that selectively shields this region and other radiosensitive organs in the abdominal area is shown here.

KINETIC STUDY OF RADIATION-REACTION-LIMITED PARTICLE ACCELERATION DURING THE RELAXATION OF UNSTABLE FORCE-FREE EQUILIBRIA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuan, Yajie; Nalewajko, Krzysztof; Zrake, Jonathan

2016-09-10

Many powerful and variable gamma-ray sources, including pulsar wind nebulae, active galactic nuclei and gamma-ray bursts, seem capable of accelerating particles to gamma-ray emitting energies efficiently over very short timescales. These are likely due to the rapid dissipation of electromagnetic energy in a highly magnetized, relativistic plasma. In order to understand the generic features of such processes, we have investigated simple models based on the relaxation of unstable force-free magnetostatic equilibria. In this work, we make the connection between the corresponding plasma dynamics and the expected radiation signal, using 2D particle-in-cell simulations that self-consistently include synchrotron radiation reactions. We focusmore » on the lowest order unstable force-free equilibrium in a 2D periodic box. We find that rapid variability, with modest apparent radiation efficiency as perceived by a fixed observer, can be produced during the evolution of the instability. The “flares” are accompanied by an increased polarization degree in the high energy band, with rapid variation in the polarization angle. Furthermore, the separation between the acceleration sites and the synchrotron radiation sites for the highest energy particles facilitates acceleration beyond the synchrotron radiation reaction limit. We also discuss the dynamical consequences of the radiation reaction, and some astrophysical applications of this model. Our current simulations with numerically tractable parameters are not yet able to reproduce the most dramatic gamma-ray flares, e.g., from the Crab Nebula. Higher magnetization studies are promising and will be carried out in the future.« less

42 CFR 37.43 - Protection against radiation emitted by roentgenographic equipment.

Code of Federal Regulations, 2011 CFR

2011-10-01

... of the National Council on Radiation Protection and Measurements in NCRP Report No. 33 “Medical X-ray and Gamma-Ray Protection for Energies up to 10 MeV—Equipment Design and Use” (issued February 1, 1968... of X-rays and Gamma Rays of up to 10 MeV” (issued September 15, 1976). These documents are hereby...

Measuring the activity of a {sup 51}Cr neutrino source based on the gamma-radiation spectrum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorbachev, V. V., E-mail: vvgor-gfb1@mail.ru; Gavrin, V. N.; Ibragimova, T. V.

A technique for the measurement of activities of intense β sources by measuring the continuous gamma-radiation (internal bremsstrahlung) spectra is developed. A method for reconstructing the spectrum recorded by a germanium semiconductor detector is described. A method for the absolute measurement of the internal bremsstrahlung spectrum of {sup 51}Cr is presented.

Inactivation of uropathogenic Escherichia coli in ground chicken meat using high pressure processing and gamma radiation, and in purge and chicken meat surfaces by ultraviolet light

USDA-ARS?s Scientific Manuscript database

Uropathogenic Escherichia coli (UPEC) are common contaminants in meat and poultry. Nonthermal food safety intervention technologies used to improve safety and shelf-life of both human and pet foods can include high pressure processing (HPP), ionizing (gamma) radiation (GR), and ultraviolet light (UV...

Enhancement of natural background gamma-radiation dose around uranium microparticles in the human body.

PubMed

Pattison, John E; Hugtenburg, Richard P; Green, Stuart

2010-04-06

Ongoing controversy surrounds the adverse health effects of the use of depleted uranium (DU) munitions. The biological effects of gamma-radiation arise from the direct or indirect interaction between secondary electrons and the DNA of living cells. The probability of the absorption of X-rays and gamma-rays with energies below about 200 keV by particles of high atomic number is proportional to the third to fourth power of the atomic number. In such a case, the more heavily ionizing low-energy recoil electrons are preferentially produced; these cause dose enhancement in the immediate vicinity of the particles. It has been claimed that upon exposure to naturally occurring background gamma-radiation, particles of DU in the human body would produce dose enhancement by a factor of 500-1000, thereby contributing a significant radiation dose in addition to the dose received from the inherent radioactivity of the DU. In this study, we used the Monte Carlo code EGSnrc to accurately estimate the likely maximum dose enhancement arising from the presence of micrometre-sized uranium particles in the body. We found that although the dose enhancement is significant, of the order of 1-10, it is considerably smaller than that suggested previously.

Effects of gamma radiation on cork wastewater: Antioxidant activity and toxicity.

PubMed

Madureira, Joana; Pimenta, Andreia I; Popescu, Larisa; Besleaga, Alexandra; Dias, Maria Inês; Santos, Pedro M P; Melo, Rita; Ferreira, Isabel C F R; Cabo Verde, Sandra; Margaça, Fernanda M A

2017-02-01

A comprehensive assessment of the toxicity and antioxidant activity of cork boiling wastewater and the effects of gamma radiation on these parameters was performed. Antioxidant activity was evaluated using different methodologies as DPPH radical scavenging activity, reducing power and inhibition of β-carotene bleaching. The results have shown that gamma radiation can induce an increase on the antioxidant activity of cork boiling wastewater. Toxicity tests were performed to access the potential added value of the irradiated wastewaters and/or minimization of the impact for discharge in the environment. Two different methods for toxicity evaluation were followed, bacterial growth inhibition test and cytotoxicity assay, in order to predict the behavior of different cells (prokaryotic and eukaryotic) in the presence of cork wastewater. Non-treated cork boiling wastewater seemed to be non-toxic for prokaryotic cells (Pseudomonas fluorescens and Bacillus subtilis) but toxic for eukaryotic cells (A549 human cells and RAW264.7 mouse cells). The gamma radiation treatment at doses of 100 kGy appeared to increase the toxicity of cork compounds for all tested cells, which could be related to a toxic effect of radiolytic products of cork compounds in the wastewaters. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of gamma radiation onto polymeric matrix with papain

NASA Astrophysics Data System (ADS)

Zulli, Gislaine; Lopes, Patrícia Santos; Velasco, Maria Valéria Robles; Alcântara, Mara Tânia Silva; Rogero, Sizue Ota; Lugao, Ademar Benévolo; Mathor, Monica Beatriz

2010-03-01

Papain is a proteolytic enzyme that has been widely used as debridement agent for scars and wound healing treatment. However, papain presents low stability, which limits its use to extemporaneous or short shelf-life formulations. The purpose of this study was to entrap papain into a polymeric matrix in order to obtain a drug delivery system that could be used as medical device. Since these systems must be sterile, gamma radiation is an interesting option and presents advantages in relation to conventional agents: no radioactive residues are formed; the product can be sterilized inside the final packaging and has an excellent reliability. The normative reference for the establishment of the sterilizing dose determines 25 kGy as the inactivation dose for viable microorganisms. A silicone dispersion was selected to prepare membranes containing 2% (w/w) papain. Irradiated and non-irradiated membranes were simultaneously assessed in order to verify whether gamma radiation interferes with the drug-releasing profile. Results showed that irradiation does not affect significantly papain release and its activity. Therefore papain shows radioresistance in the irradiation conditions applied. In conclusion, gamma radiation can be easily used as sterilizing agent without affecting the papain release profile and its activity onto the biocompatible device is studied.

Telomere Length in Aged Mayak PA Nuclear Workers Chronically Exposed to Internal Alpha and External Gamma Radiation.

PubMed

Scherthan, Harry; Sotnik, Natalia; Peper, Michel; Schrock, Gerrit; Azizova, Tamara; Abend, Michael

2016-06-01

Telomeres consist of GC-rich DNA repeats and the "shelterin" protein complex that together protect chromosome ends from fusion and degradation. Telomeres shorten with age due to incomplete end replication and upon exposure to environmental and intrinsic stressors. Exposure to ionizing radiation is known to modulate telomere length. However, the response of telomere length in humans chronically exposed to radiation is poorly understood. Here, we studied relative telomere length (RTL) by IQ-FISH to leukocyte nuclei in a group of 100 workers from the plutonium production facility at the Mayak Production Association (PA) who were chronically exposed to alpha-emitting ((239)Pu) radiation and/or gamma (photon) radiation, and 51 local residents serving as controls, with a similar mean age of about 80 years. We applied generalized linear statistical models adjusted for age at biosampling and the second exposure type on a linear scale and observed an age-dependent telomere length reduction. In those individuals with the lowest exposure, a significant reduction of about 20% RTL was observed, both for external gamma radiation (≤1 Gy) and internal alpha radiation (≤0.05-0.1 Gy to the red bone marrow). In highly exposed individuals (>0.1 Gy alpha, 1-1.5 Gy gamma), the RTL was similar to control. Stratification by gender revealed a significant (∼30%) telomere reduction in low-dose-exposed males, which was absent in females. While the gender differences in RTL may reflect different working conditions, lifestyle and/or telomere biology, absence of a dose response in the highly exposed individuals may reflect selection against cells with short telomeres or induction of telomere-protective effects. Our observations suggest that chronic systemic exposure to radiation leads to variable dose-dependent effects on telomere length.

Radiation sensitivity of Acinetobacter spp. and their redicidation for preservation of meat at low temperature.

PubMed

Saha, Sahadev Chandra; Chopade, Balu Anand

2009-08-01

In recent years, interest has been growing to preserve food including meat applying gamma radiation recommended by International Atomic Energy Agency to extend the shelf-life of meat retaining the organoleptic conditions as it is. In view of this point the present study aims to check the sensitivity of Acinetobacter spp. isolated from meat to gamma radiations. Seven species of Acinetobacter viz. A. lwoffli M1; A. baumannii M8; A. calcoaceticus M19; A. junii M20; A. johnsonnii M23; A. haemolyticus M27 and A. radioresistens M25 isolated from meat were exposed to gamma radiation at the dose level of 0.1 to 10 KGy. The D10 value of Acinetobacter was found highest 1.25 KGy in A. radioresistens M25, which was 4 to 8 times higher than other genospecies of Acinetobacter. Acinetobacter radioresistens M25 contains one plasmid of 45 Kb. The radicidation dose of 4 KGy gamma radiations was found to be sufficient to eliminate the natural contamination of meat and contamination by Acinetobacter. To eliminate radiation resistant Acinetobacter contamination a dose of 4 to 5 KGy was required. Development of the radicidation process for preservation of meat to eliminate Acinetobacter as contaminants at low temperature is one of the new and interesting phenomena. Attempts of finding the appropriate radicidation dose for preservation of meat at low temperature will open up new avenues for commercial preservation of meat.

Gamma-ray line afterglow from burst environments

NASA Technical Reports Server (NTRS)

Fencl, H. S.; Boyd, R. N.; Hartmann, Dieter

1992-01-01

We consider photoerosion and direct pair production in a medium surrounding a gamma-ray burst. The resulting secondary gamma-rays may provide diagnostic tools of these environments and, in turn, of the nature of the bursters themselves. In some instances short-lived nuclides are formed; the beta-delayed gamma-rays produced from their decays provide the signatures of the photoerosion. In addition, annihilation radiation produced from positrons resulting from direct pair production is related to the plasma conditions in the medium. We investigate the plausibility of detecting the various radiations. Under extremely favorable conditions, the photoerosion afterglow might be detectable with the present generation of detectors. However, the positron annihilation line should be detectable under a fairly wide range in the conditions of the medium.

Multi-wavelength Observations of the Flaring Gamma-ray Blazar 3C 66A in 2008 October

NASA Astrophysics Data System (ADS)

Abdo, A. A.; Ackermann, M.; Ajello, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Carrigan, S.; Casandjian, J. M.; Cavazzuti, E.; Cecchi, C.; Çelik, Ö.; Charles, E.; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; Costamante, L.; Cutini, S.; Davis, D. S.; Dermer, C. D.; de Palma, F.; Digel, S. W.; do Couto e Silva, E.; Drell, P. S.; Dubois, R.; Dumora, D.; Favuzzi, C.; Fegan, S. J.; Fortin, P.; Frailis, M.; Fuhrmann, L.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Hadasch, D.; Hayashida, M.; Hays, E.; Horan, D.; Hughes, R. E.; Itoh, R.; Jóhannesson, G.; Johnson, A. S.; Johnson, T. J.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, J.; Knödlseder, J.; Kuss, M.; Lande, J.; Latronico, L.; Lee, S.-H.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Makeev, A.; Mazziotta, M. N.; McEnery, J. E.; Mehault, J.; Michelson, P. F.; Mizuno, T.; Moiseev, A. A.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori, T.; Naumann-Godo, M.; Nestoras, I.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orlando, E.; Ormes, J. F.; Ozaki, M.; Paneque, D.; Panetta, J. H.; Parent, D.; Pelassa, V.; Pepe, M.; Pesce-Rollins, M.; Piron, F.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Reyes, L. C.; Ripken, J.; Ritz, S.; Romani, R. W.; Roth, M.; Sadrozinski, H. F.-W.; Sanchez, D.; Sander, A.; Scargle, J. D.; Sgrò, C.; Shaw, M. S.; Smith, P. D.; Spandre, G.; Spinelli, P.; Strickman, M. S.; Suson, D. J.; Takahashi, H.; Tanaka, T.; Thayer, J. B.; Thayer, J. G.; Thompson, D. J.; Tibaldo, L.; Torres, D. F.; Tosti, G.; Tramacere, A.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vilchez, N.; Vitale, V.; Waite, A. P.; Wang, P.; Winer, B. L.; Wood, K. S.; Yang, Z.; Ylinen, T.; Ziegler, M.; Acciari, V. A.; Aliu, E.; Arlen, T.; Aune, T.; Beilicke, M.; Benbow, W.; Böttcher, M.; Boltuch, D.; Bradbury, S. M.; Buckley, J. H.; Bugaev, V.; Byrum, K.; Cannon, A.; Cesarini, A.; Christiansen, J. L.; Ciupik, L.; Cui, W.; de la Calle Perez, I.; Dickherber, R.; Errando, M.; Falcone, A.; Finley, J. P.; Finnegan, G.; Fortson, L.; Furniss, A.; Galante, N.; Gall, D.; Gillanders, G. H.; Godambe, S.; Grube, J.; Guenette, R.; Gyuk, G.; Hanna, D.; Holder, J.; Hui, C. M.; Humensky, T. B.; Imran, A.; Kaaret, P.; Karlsson, N.; Kertzman, M.; Kieda, D.; Konopelko, A.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Maier, G.; McArthur, S.; McCann, A.; McCutcheon, M.; Moriarty, P.; Mukherjee, R.; Ong, R. A.; Otte, A. N.; Pandel, D.; Perkins, J. S.; Pichel, A.; Pohl, M.; Quinn, J.; Ragan, K.; Reynolds, P. T.; Roache, E.; Rose, H. J.; Schroedter, M.; Sembroski, G. H.; Senturk, G. Demet; Smith, A. W.; Steele, D.; Swordy, S. P.; Tešić, G.; Theiling, M.; Thibadeau, S.; Varlotta, A.; Vassiliev, V. V.; Vincent, S.; Wakely, S. P.; Ward, J. E.; Weekes, T. C.; Weinstein, A.; Weisgarber, T.; Williams, D. A.; Wissel, S.; Wood, M.; Villata, M.; Raiteri, C. M.; Gurwell, M. A.; Larionov, V. M.; Kurtanidze, O. M.; Aller, M. F.; Lähteenmäki, A.; Chen, W. P.; Berduygin, A.; Agudo, I.; Aller, H. D.; Arkharov, A. A.; Bach, U.; Bachev, R.; Beltrame, P.; Benítez, E.; Buemi, C. S.; Dashti, J.; Calcidese, P.; Capezzali, D.; Carosati, D.; Da Rio, D.; Di Paola, A.; Diltz, C.; Dolci, M.; Dultzin, D.; Forné, E.; Gómez, J. L.; Hagen-Thorn, V. A.; Halkola, A.; Heidt, J.; Hiriart, D.; Hovatta, T.; Hsiao, H.-Y.; Jorstad, S. G.; Kimeridze, G. N.; Konstantinova, T. S.; Kopatskaya, E. N.; Koptelova, E.; Leto, P.; Ligustri, R.; Lindfors, E.; Lopez, J. M.; Marscher, A. P.; Mommert, M.; Mujica, R.; Nikolashvili, M. G.; Nilsson, K.; Palma, N.; Pasanen, M.; Roca-Sogorb, M.; Ros, J. A.; Roustazadeh, P.; Sadun, A. C.; Saino, J.; Sigua, L. A.; Sillanää, A.; Sorcia, M.; Takalo, L. O.; Tornikoski, M.; Trigilio, C.; Turchetti, R.; Umana, G.; Belloni, T.; Blake, C. H.; Bloom, J. S.; Angelakis, E.; Fumagalli, M.; Hauser, M.; Prochaska, J. X.; Riquelme, D.; Sievers, A.; Starr, D. L.; Tagliaferri, G.; Ungerechts, H.; Wagner, S.; Zensus, J. A.; Fermi LAT Collaboration; VERITAS Collaboration; GASP-WEBT Consortium

2011-01-01

The BL Lacertae object 3C 66A was detected in a flaring state by the Fermi Large Area Telescope (LAT) and VERITAS in 2008 October. In addition to these gamma-ray observations, F-GAMMA, GASP-WEBT, PAIRITEL, MDM, ATOM, Swift, and Chandra provided radio to X-ray coverage. The available light curves show variability and, in particular, correlated flares are observed in the optical and Fermi-LAT gamma-ray band. The resulting spectral energy distribution can be well fitted using standard leptonic models with and without an external radiation field for inverse Compton scattering. It is found, however, that only the model with an external radiation field can accommodate the intra-night variability observed at optical wavelengths.

Caracterización de un sistema de telescopios Cherenkov para la detección de rayos gamma de energías del TeV desde el CASLEO

NASA Astrophysics Data System (ADS)

Melo, D.; Yelós, L. D.; Garcia, B.; Rovero, A. C.

2017-10-01

Gamma-ray astronomy opened the universe of the more energetic electromagnetic radiation using ground and orbiting instruments, which provide information for the understanding of sources of different types. Ground-based telescope arrays use Cherenkov light produced by the charged particles from extensive air showers generated in the Earth's atmosphere to identify gamma rays. This imposes a minimum energy threshold on the gamma rays to be detected. Towards the high-energy end of the spectrum, however, the amount of Cherenkov radiation produced by a gamma-ray photon guarantees its detectability, the limiting factor being the low flux of the sources. For this reason, the detection strategy consists in using arrays of small telescopes. In this work, we investigate the feasibility of detecting gamma-ray cascades using Cherenkov telescopes, in the range of 100 GeV to 2 TeV, at the CASLEO site, characterizing the response of a system of three Cherenkov telescopes.

Gamma-ray vortices from nonlinear inverse Thomson scattering of circularly polarized light.

PubMed

Taira, Yoshitaka; Hayakawa, Takehito; Katoh, Masahiro

2017-07-10

Inverse Thomson scattering is a well-known radiation process that produces high-energy photons both in nature and in the laboratory. Nonlinear inverse Thomson scattering occurring inside an intense light field is a process which generates higher harmonic photons. In this paper, we theoretically show that the higher harmonic gamma-ray produced by nonlinear inverse Thomson scattering of circularly polarized light is a gamma-ray vortex, which means that it possesses a helical wave front and carries orbital angular momentum. Our work explains a recent experimental result regarding nonlinear inverse Thomson scattering that clearly shows an annular intensity distribution as a remarkable feature of a vortex beam. Our work implies that gamma-ray vortices should be produced in various situations in astrophysics in which high-energy electrons and intense circularly polarized light fields coexist. Nonlinear inverse Thomson scattering is a promising radiation process for realizing a gamma-ray vortex source based on currently available laser and accelerator technologies, which would be an indispensable tool for exploring gamma-ray vortex science.

The Use of Gamma-Ray Imaging to Improve Portal Monitor Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ziock, Klaus-Peter; Collins, Jeff; Fabris, Lorenzo

2008-01-01

We have constructed a prototype, rapid-deployment portal monitor that uses visible-light and gamma-ray imaging to allow simultaneous monitoring of multiple lanes of traffic from the side of a roadway. Our Roadside Tracker uses automated target acquisition and tracking (TAT) software to identify and track vehicles in visible light images. The field of view of the visible camera overlaps with and is calibrated to that of a one-dimensional gamma-ray imager. The TAT code passes information on when vehicles enter and exit the system field of view and when they cross gamma-ray pixel boundaries. Based on this in-formation, the gamma-ray imager "harvests"more » the gamma-ray data specific to each vehicle, integrating its radiation signature for the entire time that it is in the field of view. In this fashion we are able to generate vehicle-specific radiation signatures and avoid source confusion problems that plague nonimaging approaches to the same problem.« less

Isolation and characterization of mold fungi and insects infecting sawmill wood, and their inhibition by gamma radiation

NASA Astrophysics Data System (ADS)

Kalawate, Aparna; Mehetre, Sayaji

2015-12-01

This article describes the isolation, identification, and characterization of wood-rotting fungi and insects, and their inhibition was studied using gamma radiation. Products manufactured from plantation timber species are deteriorated by wood-rotting fungi such as Hypocrea lixii, Fusarium proliferatum, and Aspergillus flavus, and insects such as powderpost beetles. Proper preservation methods are necessary for ensuring a long service life of wood products. In this study, wood samples were treated with 2.5% copper ethanolamine boron (CEB) (10% w/v) and subsequently irradiated with gamma rays (10 kGy). It was observed that CEB-treated and gamma-irradiated samples controlled fungi and powderpost beetles significantly. As wood is a dead organic material, penetration of chemicals into it is very difficult. Gamma rays easily pass through wooden objects with hidden eggs and dormant spores of insects and fungi, respectively. Gamma irradiation was proved very effective in reducing damage caused by both fungi and insects.

Effect of ionizing radiation on the physiological activities of ethanol extract from hizikia fusiformis cooking drips.

PubMed

Kim, Hyun-Joo; Choi, Jong-il; Kim, Duk-Jin; Kim, Jae-Hun; Soo Chun, Byeong; Hyun Ahn, Dong; Sun Yook, Hong; Byun, Myung-Woo; Kim, Mi-Jung; Shin, Myung-Gon; Lee, Ju-Woon

2009-01-01

Although the byproduct from Hizikia fusiformis industry had many nutrients, it is being wasted. In this study, the physiological activities of cooking drip extracts from H. fusiformis (CDHF) were determined to investigate the effect of a gamma and an electron beam irradiations. DPPH radical scavenging activity and tyrosinase and ACE inhibition effects of the gamma and electron beam irradiated CDHF extracts were increased with increasing irradiation dose. These were reasoned by the increase in the content of the total polyphenolic compound of CDHF by the gamma and electron beam irradiation. There were no differences for the radiation types. These results show that ionizing radiation could be used for enhancing the functional activity of CDHF which is a major by-product in Hizikia fusiformis processing, in various applications.

A superhydrophobic EP/PDMS nanocomposite coating with high gamma radiation stability

NASA Astrophysics Data System (ADS)

Zhang, Yan; Ren, Fule; Liu, Yujian

2018-04-01

The superhydrophobic coatings with high gamma radiation stability were prepared by using epoxy/polydimethylsiloxane (EP/PDMS) resins as the matrix and silica nanoparticles as the fillers. The nanocomposite coatings exhibit superhydrophobicity with a high water contact angle (WCA) of 154° and a low sliding angle of 7°. With the amount of SiO2 increasing from 0 to 30%, the surface shows the hierarchically structure gradually and its roughness raised from 4 nm to 278 nm. And little change in the WCA of the coatings (from 155° to 149°) was observed when the pH of the droplets varied from 2 to 14. In addition, the coatings also show good adhesion grade (5B), high hardness (6H) and outstanding stability for high dose gamma radiation.

Study of a number of biochemical indices of the blood and tissue of dogs after prolonged gamma-radiation

NASA Technical Reports Server (NTRS)

Alers, I.; Alersova, E.; Praslichka, T.; Mishurova, E.; Sedlakova, A.; Malatova, Z.; Akhunov, A. A.; Markelov, B. A.

1974-01-01

The glucose content in blood and the lipid content in serum and tissues of dogs exposed to chronic radiation for 3 and 5 years were studied. In tissues of these animals, the concentration of soluble DNA and DNA contained in DNP was studied in the spleen, lymph node (deep cervical node) and bone marrow of thigh bones. Results indicate that chronic gamma irradiation significantly changes concentrations of glucose in the blood, and that of several lipids in serum and tissues. A reduction in the concentration of DNP in tested organs reflects changes in the relative number of cells with various nuclear cytoplasmic ratios; most pronounced changes in biochemical indices occur in dogs exposed to chronic gamma radiation in doses of 125 rad per year.

[Neoplastic transformation of mouse fibroblasts under the influence of high-energy protons and gamma-rays].

PubMed

Voskanian, K Sh

2004-01-01

Oncoginic transformations of mouse fibroblasts C3H10T1/2 after exposure to proton energies 150 and 584 MeV were compared with fibroblast effects of gamma-radiation. Prior to exposure, cell populations (2.7 x 10(3) cells/cm2) were inoculated in plastic vials with the surface area of 75 cm2 and cultivated 11 days. Survivability was determined by comparing the number of cell colonies in irradiated and non-irradiated (control) vials. Transformation rate was calculated by dividing the total transformation focus number by the number of survived cells in a vial. Rate of oncogenic transformations after gamma- and proton (584 MeV) irradiation was essentially identical, i.e. the parameter grew rapidly at the doses < 1 Gy and slowed down at the doses > 1 Gy. In the dose interval between 1 and 5 Gy, transformation rate for proton energy 150 MeV was found low compared with gamma-radiation and proton energy 584 MeV. It is hypothesized that the different transformation rate after exposure to proton energy 150 MeV is linked with the high linear energy transfer as compared with the proton energy of 584 MeV and gamma-radiation.

Spectral properties of blast-wave models of gamma-ray burst sources

NASA Technical Reports Server (NTRS)

Meszaros, P.; Rees, M. J.; Papathanassiou, H.

1994-01-01

We calculate the spectrum of blast-wave models of gamma-ray burst sources, for various assumptions about the magnetic field density and the relativistic particle acceleration efficiency. For a range of physically plausible models we find that the radiation efficiency is high and leads to nonthermal spectra with breaks at various energies comparable to those observed in the gamma-ray range. Radiation is also predicted at other wavebands, in particular at X-ray, optical/UV, and GeV/TeV energies. We discuss the spectra as a function of duration for three basic types of models, and for cosmological, halo, and galactic disk distances. We also evaluate the gamma-ray fluences and the spectral characteristics for a range of external densities. Impulsive burst models at cosmological distances can satisfy the conventional X-ray paucity constraint S(sub x)/S(sub gamma)less than a few percent over a wide range of durations, but galactic models can do so only for bursts shorter than a few seconds, unless additional assumptions are made. The emissivity is generally larger for bursts in a denser external environment, with the efficiency increasing up to the point where all the energy input is radiated away.

Effects of gamma irradiation on the protein characteristics and functional properties of sesame (Sesamum indicum L.) seeds

NASA Astrophysics Data System (ADS)

Hassan, Amro B.; Mahmoud, Nagat S.; Elmamoun, Khalid; Adiamo, Oladipupo Q.; Mohamed Ahmed, Isam A.

2018-03-01

This study was aimed at investigating the effect of gamma irradiation at various doses (0.5, 1.0, 1.5 and 2.0 kGy) on protein characteristics and functional properties of sesame seeds. Gamma radiation at high doses (>1.0 kGy) significantly (P ≤ 0.05) increased globulin and albumin fractions of sesame protein. Concomitant (P ≤ 0.05) increase of in-vitro protein digestibility was noticed in irradiated sesame flour compared to non-radiated sample. Maximum protein solubility was observed in sesame flour irradiated at 1.0 kGy. SDS-PAGE electrophoretic patterns of total sesame protein were not affected by irradiation process. Significant enhancement (P ≤ 0.05) in emulsification capacity (EC) and emulsion stability (ES) was recorded after irradiation at a dose level of 1.0 and 1.5-2.0 kGy, respectively. Foaming capacity reached a significantly maximum value in sesame flour irradiated at 1.0 kGy while foaming stability was not significantly affected by gamma irradiation. It can be concluded that gamma radiation enhances the protein and functional properties of sesame flour and thus can be employed as an effective method of preserving sesame flour and its products.

MEASUREMENTS OF GAMMA-RAY DOSES OF DIFFERENT RADIOISOTOPES BY THE TEST-FILM METHOD (in German)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Domanus, J.; Halski, L.

The test-film method seems to be most suitable for systematic, periodical measurements of individual doses of ionizing radiation. Persons handling radioisotopes are irradiated with gamma rays of different energies. The energy of gamma radiation lies within much broader limits than is the case with x rays. Therefore it was necessary to check whether the test-film method is suitable for measuring doses of gamma-rays of such different energies and to choose the proper combination of film and screen to reach the necessary measuring range. Polish films, Foton Rentgen and Foton Rentgen Super and films from the German Democratic Republic, Agfa Texomore » R and Agfa Texo S were tested. Expositions were made without intensifying screens as well as with lead and fluorescent screens. The investigations showed that for dosimetric purposes the Foton Rentgen Super films are most suitable. However, not one of the film-screen combinations gave satisfactory results for radioisotopes with radiation of different energies. In such a case the test-film method gives only approximate results. If, on the contrary, gamma energies do not differ greatly, the test- film method proves to be quite good. (auth)« less

Effect of Gamma Radiation on the Ripening of Bartlett Pears 1

PubMed Central

Maxie, E. C.; Sommer, N. F.; Muller, Carlos J.; Rae, Henry L.

1966-01-01

Gamma radiation at doses of 300 Krad or more inhibits the ripening of Bartlett pears (Pyrus communis L.). Immediately after irradiation there is a transitory burst of C2H4, which subsequently declines in fruits subjected to inhibitory doses. Ethylene production associated with ripening begins at the same time in unirradiated fruits and those subjected to noninhibitory doses, but the latter produces much more C2H4 at the climacteric peak. Fruits subjected to inhibitory doses produce low levels of C2H4 unless subjected to exogenously applied C2H4, whereupon they produce enough of the gas to induce ripening in unirradiated fruits. Pears subjected to 300 and 400 Krad of gamma rays did not ripen even when held in a flowing atmosphere containing 1000 ppm of C2H4 for 8 days at 20°. It is concluded that the action of gamma rays on Bartlett pears involves both an inhibition of C2H4 production and a decreased sensitivity of the fruit to the ripening action of the gas. Ripening of Bartlett pears is inhibited by gamma radiation only when applied to preclimacteric fruit. PMID:16656274

A comparison of neutron and gamma damage effects on silica glass in a nuclear reactor radiation environment

NASA Astrophysics Data System (ADS)

Holcomb, David E.; Miller, Don W.

1993-08-01

A study of the relative damage effects of neutrons and gamma rays on silica glass in a nuclear reactor radiation environment is reported. The neutron and gamma energy spectra of the Ohio State University Research Reactor beam port #1 were applied to silica glass to obtain primary knock-on charged particle energy spectra. The resultant charged particle spectra were then applied to the polyatomic forms of the Lindhard et al. integrodifferential equation for damage energy and the Parkin and Coulter integrodifferential equation for net atomic displacement. The results show that near a nuclear reactor core the vast majority of the dose to silica is due to gamma rays (factor of roughly 40) and that neutrons cause much more displacement damage than gamma rays (35 times the oxygen displacement rate and 500 times the silicon displacement rate). However, pure silica core optical fibers irradiated in a nuclear reactor's mixed neutron/gamma environment exhibit little difference in transmission loss on an equal dose basis compared to fibers irradiated in a gamma only environment, indicating that atomic displacement is not a significant damage mechanism.

A NOVEL EMISSION SPECTRUM FROM A RELATIVISTIC ELECTRON MOVING IN A RANDOM MAGNETIC FIELD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teraki, Yuto; Takahara, Fumio, E-mail: teraki@vega.ess.sci.osaka-u.ac.jp

2011-07-10

We numerically calculate the radiation spectrum from relativistic electrons moving in small-scale turbulent magnetic fields expected in high-energy astrophysical sources. Such a radiation spectrum is characterized by the strength parameter a = {lambda}{sub B} e|B|/mc {sup 2}, where {lambda}{sub B} is the length scale of the turbulent field. When a is much larger than the Lorentz factor of a radiating electron {gamma}, synchrotron radiation is realized, while a << 1 corresponds to the so-called jitter radiation regime. Because for 1 < a < {gamma} we cannot use either approximations, we should have recourse to the Lienard-Wiechert potential to evaluate themore » radiation spectrum, which is performed in this Letter. We generate random magnetic fields assuming Kolmogorov turbulence, inject monoenergetic electrons, solve the equation of motion, and calculate the radiation spectrum. We perform numerical calculations for several values of a with {gamma} = 10. We obtain various types of spectra ranging between jitter radiation and synchrotron radiation. For a {approx} 7, the spectrum takes a novel shape which had not been noticed up to now. It is like a synchrotron spectrum in the middle energy region, but in the low frequency region it is a broken power law and in the high frequency region an extra power-law component appears beyond the synchrotron cutoff. We give a physical explanation of these features.« less

Gamma-Ray background spectrum and annihilation rate in the baryon-symmetric big-bang cosmology

NASA Technical Reports Server (NTRS)

Puget, J. L.

1973-01-01

An attempt was made to extract experimental data on baryon symmetry by observing annihilation products. Specifically, gamma rays and neutrons with long mean free paths were analyzed. Data cover absorption cross sections and radiation background of the 0.511 MeV gamma rays from positron annihilations and the 70 MeV gamma rays from neutral pion decay.

Gamma-irradiated bacterial preparation having anti-tumor activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vass, A.A.; Tyndall, R.L.; Terzaghi-Howe, P.

1999-11-16

This application describes a bacterial preparation from Pseudomonas species isolated {number{underscore}sign}15 ATCC 55638 that has been exposed to gamma radiation exhibits cytotoxicity that is specific for neoplastic carcinoma cells. A method for obtaining a bacterial preparation having antitumor activity consists of suspending a bacterial isolate in media and exposing the suspension to gamma radiation. A bacterial preparation of an aged culture of an amoeba-associated bacteria exhibits anti-reverse transcriptase activity. A method for obtaining a bacterial preparation having anti-reverse transcriptase activity from an amoeba-associated bacterial isolate grown to stationary phase is disclosed.

Computer registration of radioactive indicator-dilution curves.

PubMed

Shepherd, A P; Perry, M A; Alexander, G M; Granger, D N; Riedel, G L; Kvietys, P R; Franke, C P

1983-12-01

A system is described for recording indicator-dilution curves produced by gamma radiation-emitting tracers. The system consists of a flow-through cuvette in a well counter, appropriate commercially available gamma radiation-detecting equipment, an Apple II computer, and a two-channel pulse-counting interface of our own design. With the counting interface and the software described here, an investigator can simultaneously record two indicator-dilution curves produced by gamma emitters. Instead of having to wait hours or days for results, the investigator can watch the data being recorded and display the results in graphic form almost immediately after each injection.

The radiated electromagnetic field from collimated gamma rays and electron beams in air

NASA Astrophysics Data System (ADS)

Tumolillo, T. A.; Wondra, J. P.; Hobbs, W. E.; Smith, K.

1980-12-01

Nuclear weapons effects computer codes are used to study the electromagnetic field produced by gamma rays or by highly relativistic electron beams moving through the air. Consideration is given to large-area electron and gamma beams, small-area electron beams, variation of total beam current, variation of pressure in the beam channel, variation of the beam rise time, variation of beam radius, far-field radiated signals, and induced current on a system from a charged-particle beam. The work has application to system EMP coupling from nuclear weapons or charged-particle-beam weapons.

USE OF MODELS FOR GAMMA SHIELDING STUDIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clifford, C.E.

1962-02-01

The use of models for shielding studies of buildings exposed to gamma radiation was evaluated by comparing the dose distributions produced in a blockhouse with movable inside walls exposed to 0.66 Mev gamma radiation with corresponding distributions in an iron 1 to 10 scale model. The effects of air and ground scaling on the readings in the model were also investigated. Iron appeared to be a suitable model material for simple closed buildings but for more complex structures it appeared that the use of iron models would progressively overestimite the gamms shielding protection as the complexity increased. (auth)

Neutron and gamma dose and spectra measurements on the Little Boy replica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoots, S.; Wadsworth, D.

1984-06-01

The radiation-measurement team of the Weapons Engineering Division at Lawrence Livermore National Laboratory (LLNL) measured neutron and gamma dose and spectra on the Little Boy replica at Los Alamos National Laboratory (LANL) in April 1983. This assembly is a replica of the gun-type atomic bomb exploded over Hiroshima in 1945. These measurements support the National Academy of Sciences Program to reassess the radiation doses due to atomic bomb explosions in Japan. Specifically, the following types of information were important: neutron spectra as a function of geometry, gamma to neutron dose ratios out to 1.5 km, and neutron attenuation in themore » atmosphere. We measured neutron and gamma dose/fission from close-in to a kilometer out, and neutron and gamma spectra at 90 and 30/sup 0/ close-in. This paper describes these measurements and the results. 12 references, 13 figures, 5 tables.« less

Gamma-ray pulsars: Radiation processes in the outer magnetosphere

NASA Technical Reports Server (NTRS)

Romani, Roger W.

1996-01-01

We describe an emission model for gamma ray pulsars based on curvature radiation-reaction limited charges in the outer magnetosphere. We show how pair production on thermal surface flux can limit the acceleration zones. Estimates for the efficiency of GeV photon production eta gamma and the gamma-ray beaming fraction are derived, including their dependence on pulsar parameters. In general eta gamma increases with pulsar age, but is decreased for low magnetic fields and for small magnetic inclinations. We argue that this produces GeV pulse profiles, curvature spectra and detection statistics consistent with the observations. We also describe the optical through X-ray pulsar synchrotron spectrum and the spectral variations with pulsar phase. A test computation for Vela-like parameters reproduces phase-resolved GeV spectra consistent with those observed by EGRET. Finally we comment on very high energy pulsed emission and particle production and note extensions needed to allow a more complete pulsar model.

Gamma-ray astronomy

NASA Technical Reports Server (NTRS)

Ramaty, R.; Lingenfelter, R. E.

1982-01-01

Cosmic gamma rays, the physical processes responsible for their production and the astrophysical sites from which they were seen are reported. The bulk of the observed gamma ray emission is in the photon energy range from about 0.1 MeV to 1 GeV, where observations are carried out above the atmosphere. There are also, however, gamma ray observations at higher energies obtained by detecting the Cerenkov light produced by the high energy photons in the atmosphere. Gamma ray emission was observed from sources as close as the Sun and the Moon and as distant as the quasar 3C273, as well as from various other galactic and extragalactic sites. The radiation processes also range from the well understood, e.g. energetic particle interactions with matter, to the still incompletely researched, such as radiation transfer in optically thick electron positron plasmas in intense neutron star magnetic fields.

Fourier transform infrared spectroscopic study of gamma irradiated SiO2 nanoparticles

NASA Astrophysics Data System (ADS)

Huseynov, Elchin; Garibov, Adil; Mehdiyeva, Ravan; Huseynova, Efsane

2018-03-01

In the present work, nano SiO2 particles are investigated before and after gamma irradiation (25, 50, 75, 100 and 200 kGy) using Fourier transform infrared (FTIR) spectroscopy method for the wavenumber between 400-4000 cm-1. It is found that as a result of spectroscopic analysis, five new peaks have appeared after gamma radiation. Two of new obtained peaks (which are located at 687 cm-1 and 2357 cm-1 of wavenumber) were formed as a result of gamma radiation interaction with Si-O bonds. Another three new peaks (peaks appropriate to 941, 2052 and 2357 cm-1 values of wavenumber) appear as a result of interaction of water with nano SiO2 particles after gamma irradiation. It has been defined as asymmetrical bending vibration, symmetrical bending vibration, symmetrical stretching vibration and asymmetrical stretching vibration of Si-O bonds appropriate to peaks.

Neutron and gamma irradiation effects on power semiconductor switches

NASA Technical Reports Server (NTRS)

Schwarze, G. E.; Frasca, A. J.

1990-01-01

The performance characteristics of high-power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation.

Neutron and gamma irradiation effects on power semiconductor switches

NASA Technical Reports Server (NTRS)

Schwarze, G. E.; Frasca, A. J.

1990-01-01

The performance characteristics of high power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation.

Study of gamma detection capabilities of the REWARD mobile spectroscopic system

NASA Astrophysics Data System (ADS)

Balbuena, J. P.; Baptista, M.; Barros, S.; Dambacher, M.; Disch, C.; Fiederle, M.; Kuehn, S.; Parzefall, U.

2017-07-01

REWARD is a novel mobile spectroscopic radiation detector system for Homeland Security applications. The system integrates gamma and neutron detection equipped with wireless communication. A comprehensive simulation study on its gamma detection capabilities in different radioactive scenarios is presented in this work. The gamma detection unit consists of a precise energy resolution system based on two stacked (Cd,Zn)Te sensors working in coincidence sum mode. The volume of each of these CZT sensors is 1 cm3. The investigated energy windows used to determine the detection capabilities of the detector correspond to the gamma emissions from 137Cs and 60Co radioactive sources (662 keV and 1173/1333 keV respectively). Monte Carlo and Technology Computer-Aided Design (TCAD) simulations are combined to determine its sensing capabilities for different radiation sources and estimate the limits of detection of the sensing unit as a function of source activity for several shielding materials.

Energetic neutron and gamma-ray spectra under the earth radiation belts according to ``SALUTE-7''-``KOSMOS-1686'' orbital complex and ``CORONAS-I'' satellite data

NASA Astrophysics Data System (ADS)

Bogomolov, A. V.; Dmitriev, A. V.; Myagkova, I. N.; Ryumin, S. P.; Smirnova, O. N.; Sobolevsky, I. M.

The spectra of neutrons > 10 MeV and gamma-rays 1.5-100 MeV under the Earth Radiation Belts, restored from the data, obtained onboard orbital complex ``SALUTE-7''-``KOSMOS-1686'', are presented. The spectra shapes are similar to those for albedo neutrons and gamma-rays, but absolute values of their fluxes (0.2 cm^-2 s^-1 for neutrons, 0.8 cm^-2 s^-1 for gamma-rays at the equator and 1.2 cm^-2 s^-1, 1.9 cm^-2 s^-1, accordingly, at L=1.9) are several times as large. It is possibly explained by the fact that most of the detected particles were produced by the cosmic ray interactions with the orbital complex matter. Neutron and gamma-ray fluxes obtained from ``CORONAS-I'' data are near those for albedo particles.

SKYSINE-II procedure: calculation of the effects of structure design on neutron, primary gamma-ray and secondary gamma-ray dose rates in air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lampley, C.M.

1979-01-01

An updated version of the SKYSHINE Monte Carlo procedure has been developed. The new computer code, SKYSHINE-II, provides a substantial increase in versatility in that the program possesses the ability to address three types of point-isotropic radiation sources: (1) primary gamma rays, (2) neutrons, and (3) secondary gamma rays. In addition, the emitted radiation may now be characterized by an energy emission spectrum product of a new energy-dependent atmospheric transmission data base developed by Radiation Research Associates, Inc. for each of the three source types described above. Most of the computational options present in the original program have been retainedmore » in the new version. Hence, the SKYSHINE-II computer code provides a versatile and viable tool for the analysis of the radiation environment in the vicinity of a building structure containing radiation sources, situated within the confines of a nuclear power plant. This report describes many of the calculational methods employed within the SKYSHINE-II program. A brief description of the new data base is included. Utilization instructions for the program are provided for operation of the SKYSHINE-II code on the Brookhaven National Laboratory Central Scientific Computing Facility. A listing of the source decks, block data routines, and the new atmospheric transmission data base are provided in the appendices of the report.« less

Two-year follow-up after intracoronary gamma radiation therapy.

PubMed

Condado, J A; Waksman, R; Calderas, C; Saucedo, J; Lansky, A

1999-01-01

Neointimal hyperplasia and unfavorable remodeling have been demonstrated to be the major limitation to endovascular revascularization procedures. Intracoronary gamma radiation therapy has been shown to reduce the restenosis index. However, the late effects of these novel procedures are unknown. To evaluate the long-term effects on clinical and angiographic outcome of endovascular gamma radiation therapy following percutaneous transluminal coronary angioplasty (PTCA), serial angiography over a 2-year period was performed in 21 patients (22 lesions) who were treated with 192Ir in doses of 20-25 Gy after PTCA. Angiograms were analyzed using quantitative methods (QCA). The mean late loss between PTCA and 6 months was 0.20 +/- 0.59 and 0.13 +/- 0.84 between 6 months and 2 years. At 6 months, angiographic binary restenosis was present in six arteries (27.2%). At 2 years, binary restenosis was observed in six arteries (27.2%), including one patient who had developed restenosis and excluding one patient with spontaneous regression. Two early pseudoaneurysms and two late aneurysms were observed at 6 months, with little increase at 2 years. No other angiographic complication was observed. None of the patients or medical staff developed complications or illnesses that could be related to the effects of the radiation procedure. Gamma radiation therapy decreases late luminal loss, is safe and free of unexpected complications at 6 months follow-up, with no significant changes or late complications at 2-years' follow-up.

High resolution x-ray and gamma ray imaging using diffraction lenses with mechanically bent crystals

DOEpatents

Smither, Robert K [Hinsdale, IL

2008-12-23

A method for high spatial resolution imaging of a plurality of sources of x-ray and gamma-ray radiation is provided. High quality mechanically bent diffracting crystals of 0.1 mm radial width are used for focusing the radiation and directing the radiation to an array of detectors which is used for analyzing their addition to collect data as to the location of the source of radiation. A computer is used for converting the data to an image. The invention also provides for the use of a multi-component high resolution detector array and for narrow source and detector apertures.

Actively driven thermal radiation shield

DOEpatents

Madden, Norman W.; Cork, Christopher P.; Becker, John A.; Knapp, David A.

2002-01-01

A thermal radiation shield for cooled portable gamma-ray spectrometers. The thermal radiation shield is located intermediate the vacuum enclosure and detector enclosure, is actively driven, and is useful in reducing the heat load to mechanical cooler and additionally extends the lifetime of the mechanical cooler. The thermal shield is electrically-powered and is particularly useful for portable solid-state gamma-ray detectors or spectrometers that dramatically reduces the cooling power requirements. For example, the operating shield at 260K (40K below room temperature) will decrease the thermal radiation load to the detector by 50%, which makes possible portable battery operation for a mechanically cooled Ge spectrometer.

Assessment of Ethylene Vinyl-Acetato Copolymer (EVA) Samples Bombarded by Gamma Radiation via Linearity Analyses

NASA Astrophysics Data System (ADS)

de Oliveira, L. N.; do Nascimento, E. O.; Schimidt, F.; Antonio, P. L.; Caldas, L. V. E.

2018-03-01

Materials with the potential to become dosimeters are of interest in radiation physics. In this research, the materials were analyzed and compared in relation to their linearity ranges. Samples of ethylene vinyl-acetate copolymer (EVA) were irradiated with doses from 10 Gy to 10 kGy using a 60Co Gamma-Cell system 220 and evaluated with the FTIR technique. The linearity analyses were applied through two methodologies, searching for linear regions in their response. The results show that both applied analyses indicate linear regions in defined dose interval. The radiation detectors EVA can be useful for radiation dosimetry in intermediate and high doses.

Effect of gamma and e-beam radiation on the essential oils of Thymus vulgaris thymoliferum, Eucalyptus radiata, and Lavandula angustifolia.

PubMed

Haddad, Mohamed; Herent, Marie-France; Tilquin, Bernard; Quetin-Leclercq, Joëlle

2007-07-25

The microbiological contamination of raw plant materials is common and may be adequately reduced by radiation processing. This study evaluated the effects of gamma- and e-beam ionizing radiations (25 kGy) on three plants used as food or as medicinal products (Thymus vulgaris L., Eucalyptus radiata D.C., and Lavandula angustifolia Mill.) as well as their effects on extracted or commercial essential oils and pure standard samples. Comparison between irradiated and nonirradiated samples was performed by GC/FID and GC/MS. At the studied doses, gamma and e-beam ionizing radiation did not induce any detectable qualitative or quantitative significant changes in the contents and yields of essential oils immediately after ionizing radiation of plants or commercial essential oils and standards. As the maximum dose tested (25 kGy) is a sterilizing dose (much higher than doses used for decontamination of vegetable drugs), it is likely that even decontamination with lower doses will not modify yields or composition of essential oils of these three plants.

SAS-2 observations of the diffuse gamma radiation in the galactic latitude interval 10 deg absolute b or equal to 90 deg

NASA Technical Reports Server (NTRS)

Fichtel, C. E.; Hartman, R. C.; Kniffen, D. A.; Thompson, D. J.; Oegelman, H. B.; Oezel, M. E.; Tuemer, T.

1977-01-01

An analysis of all of the second small astronomy satellite gamma-ray data for galactic latitudes with the absolute value of b 10 deg has shown that the intensity varies with galactic latitude, being larger near 10 deg than 90 deg. For energies above 100 MeV the gamma-ray data are consistent with a latitude distribution of the form I(b) = C sub 1 + C sub 2/sin b, with the second term being dominant. This result suggests that the radiation above 100 MeV is coming largely from local regions of the galactic disk. Between 35 and 100 MeV, a similar equation is also a good representation of the data, but here the two terms are comparable. These results indicate that the diffuse radiation above 35 MeV consists of two parts, one with a relatively hard galactic component and the other an isotropic, steep spectral component which extrapolates back well to the low energy diffuse radiation. The steepness of the diffuse isotropic component places significant constraints on possible theoretical models of this radiation.

A SPACE TRAJECTORY RADIATION EXPOSURE PROCEDURE FOR CISLUNAR MISSIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cranford, W.; Falkenbury, R.F.; Miller, R.A.

1962-07-31

The Space Trajectory Radiation Exposure Procedure (STREP) is designed for use in computing the timeintegrated spectra for any specified trajectory in cislunar space for any combination of the several components of space radiations. These components include Van Allen protons and electrons; solar-flare protons, electrons, heavy particles, and gamma radiation; cosmic protons and heavy particles; albedo neutrons, and aurora borealis gamma radiation. The program can also be used to calculate the accumulated dose behind a thin vehicle skin at any time after the start of the mission. The technique of interpolation for intermediate points along the prescribed space trajectory is describedmore » in detail. The method of representation of the space radiation data as input for the calculation of the dose and time-integrated spectra is discussed. (auth)« less

[Induction of glutathione and activation of immune functions by low-dose, whole-body irradiation with gamma-rays].

PubMed

Kojima, Shuji

2006-10-01

We first examined the relation between the induction of glutathione and immune functions in mice after low-dose gamma-ray irradiation. Thereafter, inhibition of tumor growth by radiation was confirmed in Ehrlich solid tumor (EST)-bearing mice. The total glutathione level of the splenocytes transiently increased soon after irradiation and reached a maximum at around 4 h postirradiation. Thereafter, the level reverted to the 0 h value by 24 h postirradiation. A significantly high splenocyte proliferative response was also recognized 4 h postirradiation. Natural killer (NK) activity was also increased significantly in a similar manner. The time at which the response reached the maximum coincided well with that of maximum total glutathione levels of the splenocytes in the gamma-ray-irradiated mice. Reduced glutathione exogenously added to splenocytes obtained from normal mice enhanced the proliferative response and NK activity in a dose-dependent manner. The inhibitory effects of radiation on tumor growth was then examined in EST-bearing mice. Repeated low-dose irradiation (0.5 Gy, four times, before and within an early time after inoculation) significantly delayed the tumor growth. Finally, the effect of single low-dose (0.5 Gy), whole-body gamma-ray irradiation on immune balance was examined to elucidate the mechanism underlying the antitumor immunity. The percentage of B cells in blood lymphocytes was selectively decreased after radiation, concomitant with an increase in that of the helper T cell population. The IFN-gamma level in splenocyte culture prepared from EST-bearing mice was significantly increased 48 h after radiation, although the level of IL-4 was unchanged. IL-12 secretion from macrophages was also enhanced by radiation. These results suggest that low-dose gamma-rays induce Th1 polarization and enhance the activities of tumoricidal effector cells, leading to an inhibition of tumor growth.

Top ten models constrained by b {yields} s{gamma}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hewett, J.L.

1994-12-01

The radiative decay b {yields} s{gamma} is examined in the Standard Model and in nine classes of models which contain physics beyond the Standard Model. The constraints which may be placed on these models from the recent results of the CLEO Collaboration on both inclusive and exclusive radiative B decays is summarized. Reasonable bounds are found for the parameters in some cases.

Effects of 1-MeV gamma radiation on a multi-anode microchannel array detector tube

NASA Technical Reports Server (NTRS)

Timothy, J. G.; Bybee, R. L.

1979-01-01

A multianode microchannel array (MAMA) detector tube without a photocathode was exposed to a total dose of 1,000,000 rads of 1-MeV gamma radiation from a Co-60 source. The high-voltage characteristic of the microchannel array plate, average dark count, gain, and resolution of pulse height distribution characteristics showed no degradation after this total dose. In fact, the degassing of the microchannels induced by the high radiation flux had the effect of cleaning up the array plate and improving its characteristics.

Assessment of Gamma Radiation Resistance of Spores Isolated from the Spacecraft Assembly Facility During MSL Assembly

NASA Technical Reports Server (NTRS)

Chopra, Arsh; Ramirez, Gustavo A.; Venkateswaran, Kasthuri J.; Vaishampayan, Parag A.

2011-01-01

Spore forming bacteria, a common inhabitant of spacecraft assembly facilities, are known to tolerate extreme environmental conditions such as radiation, desiccation, and high temperatures. Since the Viking era (early 1970's), spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. There is a growing concern that desiccation and extreme radiation resistant spore forming microorganisms associated with spacecraft surfaces can withstand space environmental conditions and subsequently proliferate on another solar body. Such forward contamination would certainly jeopardize future life detection or sample return technologies. It is important to recognize that different classes of organisms are critical while calculating the probability of contamination, and methods must be devised to estimate their abundances. Microorganisms can be categorized based on radiation sensitivity as Type A, B, C, and D. Type C represents spores resistant to radiation (10% or greater survival above 0.8 mRad gamma radiation). To address these questions we have purified 96 spore formers, isolated during planetary protection efforts of Mars Science Laboratory assembly for gamma radiation resistance. The spores purified and stored will be used to generate data that can be used further to model and predict the probability of forward contamination.

Assessment of Gamma Radiation Resistance of Spores Isolated from the Spacecraft Assembly Facility During MSL Assembly

NASA Technical Reports Server (NTRS)

Chopra, Arsh; Ramirez, Gustavo A.; Vaishampayan, Parag A.; Venkateswaran, Kasthuri J.

2011-01-01

Spore forming bacteria, a common inhabitant of spacecraft assembly facilities, are known to tolerate extreme environmental conditions such as radiation, desiccation, and high temperatures. Since the Viking era (early 1970's), spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. There is a growing concern that desiccation and extreme radiation resistant spore forming microorganisms associated with spacecraft surfaces can withstand space environmental conditions and subsequently proliferate on another solar body. Such forward contamination would certainly jeopardize future life detection or sample return technologies. It is important to recognize that different classes of organisms are critical while calculating the probability of contamination, and methods must be devised to estimate their abundances. Microorganisms can be categorized based on radiation sensitivity as Type A, B, C, and D. Type C represents spores resistant to radiation (10% or greater survival above 0.8 Mrad gamma radiation). To address these questions we have purified 96 spore formers, isolated during planetary protection efforts of Mars Science Laboratory assembly for gamma radiation resistance. The spores purified and stored will be used to generate data that can be used further to model and predict the probability of forward contamination.

MCNP-based computational model for the Leksell gamma knife.

PubMed

Trnka, Jiri; Novotny, Josef; Kluson, Jaroslav

2007-01-01

We have focused on the usage of MCNP code for calculation of Gamma Knife radiation field parameters with a homogenous polystyrene phantom. We have investigated several parameters of the Leksell Gamma Knife radiation field and compared the results with other studies based on EGS4 and PENELOPE code as well as the Leksell Gamma Knife treatment planning system Leksell GammaPlan (LGP). The current model describes all 201 radiation beams together and simulates all the sources in the same time. Within each beam, it considers the technical construction of the source, the source holder, collimator system, the spherical phantom, and surrounding material. We have calculated output factors for various sizes of scoring volumes, relative dose distributions along basic planes including linear dose profiles, integral doses in various volumes, and differential dose volume histograms. All the parameters have been calculated for each collimator size and for the isocentric configuration of the phantom. We have found the calculated output factors to be in agreement with other authors' works except the case of 4 mm collimator size, where averaging over the scoring volume and statistical uncertainties strongly influences the calculated results. In general, all the results are dependent on the choice of the scoring volume. The calculated linear dose profiles and relative dose distributions also match independent studies and the Leksell GammaPlan, but care must be taken about the fluctuations within the plateau, which can influence the normalization, and accuracy in determining the isocenter position, which is important for comparing different dose profiles. The calculated differential dose volume histograms and integral doses have been compared with data provided by the Leksell GammaPlan. The dose volume histograms are in good agreement as well as integral doses calculated in small calculation matrix volumes. However, deviations in integral doses up to 50% can be observed for large volumes such as for the total skull volume. The differences observed in treatment of scattered radiation between the MC method and the LGP may be important in this case. We have also studied the influence of differential direction sampling of primary photons and have found that, due to the anisotropic sampling, doses around the isocenter deviate from each other by up to 6%. With caution about the details of the calculation settings, it is possible to employ the MCNP Monte Carlo code for independent verification of the Leksell Gamma Knife radiation field properties.

Assessment of background gamma radiation levels using airborne gamma ray spectrometer data over uranium deposits, Cuddapah Basin, India - A comparative study of dose rates estimated by AGRS and PGRS.

PubMed

Srinivas, D; Ramesh Babu, V; Patra, I; Tripathi, Shailesh; Ramayya, M S; Chaturvedi, A K

2017-02-01

The Atomic Minerals Directorate for Exploration and Research (AMD) has conducted high-resolution airborne gamma ray spectrometer (AGRS), magnetometer and time domain electromagnetic (TDEM) surveys for uranium exploration, along the northern margins of Cuddapah Basin. The survey area includes well known uranium deposits such as Lambapur-Peddagattu, Chitrial and Koppunuru. The AGRS data collected for uranium exploration is utilised for estimating the average absorbed rates in air due to radio-elemental (potassium in %, uranium and thorium in ppm) distribution over these known deposit areas. Further, portable gamma ray spectrometer (PGRS) was used to acquire data over two nearby locations one from Lambapur deposit, and the other from known anomalous zone and subsequently average gamma dose rates were estimated. Representative in-situ rock samples were also collected from these two areas and subjected to radio-elemental concentration analysis by gamma ray spectrometer (GRS) in the laboratory and then dose rates were estimated. Analyses of these three sets of results complement one another, thereby providing a comprehensive picture of the radiation environment over these deposits. The average absorbed area wise dose rate level is estimated to be 130 ± 47 nGy h -1 in Lambapur-Peddagattu, 186 ± 77 nGy h -1 in Chitrial and 63 ± 22 nGy h -1 in Koppunuru. The obtained average dose levels are found to be higher than the world average value of 54 nGy h -1 . The gamma absorbed dose rates in nGy h -1 were converted to annual effective dose rates in mSv y -1 as proposed by the United Nations Scientific Committee on the Effect of Atomic Radiation (UNSCEAR). The annual average effective dose rates for the entire surveyed area is 0.12 mSv y -1 , which is much lower than the recommended limit of 1 mSv y -1 by International Commission on Radiation protection (ICRP). It may be ascertained here that the present study establishes a reference data set (baseline) in these areas to assess any changes in gamma radiation levels due to mining and milling activities in future. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ionizing radiation potentiates the induction of nitric oxide synthase by interferon-gamma (Ifn-gamma) or Ifn-gamma and lipopolysaccharide in bnl cl.2 murine embryonic liver cells: role of hydrogen peroxide.

PubMed

Yoo, J C; Pae, H O; Choi, B M; Kim, W I; Kim, J D; Kim, Y M; Chung, H T

2000-02-01

The effects of ionizing irradiation on the nitric oxide (NO) production in murine embryonic liver cell line, BNL CL.2 cells, were investigated. Various doses (5-40 Gy) of radiation made BNL CL.2 cells responsive to interferon-gamma alone for the production of NO in a dose-dependent manner. Small amounts of lipopolysaccharide (LPS) or tumor necrosis factor-alpha (TNF-alpha) synergized with IFN-gamma in the production of NO from irradiated BNL CL.2 cells, even though LPS or TNF-alpha alone did not induce NO production from the same cells. Immunoblots showed parallel induction of inducible nitric oxide synthase (iNOS). NO production in irradiated BNL CL.2 cells by IFN-gamma or IFN-gamma plus LPS was decreased by the addition of catalase, suggesting that H(2)O(2) produced by ionizing irradiation primed the cells to trigger NO production in response to IFN-gamma or IFN-gamma plus LPS. Furthermore, the treatment of nongamma-irradiated BNL CL.2 cells with H(2)O(2) made the cells responsive to IFN-gamma or IFN-gamma plus LPS for the production of NO. This study shows that ionizing irradiation has the ability to induce iNOS gene expression in responsive to IFN-gamma via the formation of H(2)O(2) in BNL CL.2 murine embryonic liver cells.

Induction of genomic instability in TK6 human lymphoblasts exposed to 137Cs gamma radiation: comparison to the induction by exposure to accelerated 56Fe particles

NASA Technical Reports Server (NTRS)

Evans, Helen H.; Horng, Min-Fen; Ricanati, Marlene; Diaz-Insua, M.; Jordan, Robert; Schwartz, Jeffrey L.

2003-01-01

The induction of genomic instability in TK6 human lymphoblasts by exposure to (137)Cs gamma radiation was investigated by measuring the frequency and characteristics of unstable clones isolated approximately 36 generations after exposure. Clones surviving irradiation and control clones were analyzed for 17 characteristics including chromosomal aberrations, growth defects, alterations in response to a second irradiation, and mutant frequencies at the thymidine kinase and Na(+)/K(+) ATPase loci. Putative unstable clones were defined as those that exhibited a significant alteration in one or more characteristics compared to the controls. The frequency and characteristics of the unstable clones were compared in clones exposed to (137)Cs gamma rays or (56)Fe particles. The majority of the unstable clones isolated after exposure to either gamma rays or (56)Fe particles exhibited chromosomal instability. Alterations in growth characteristics, radiation response and mutant frequencies occurred much less often than cytogenetic alterations in these unstable clones. The frequency and complexity of the unstable clones were greater after exposure to (56)Fe particles than to gamma rays. Unstable clones that survived 36 generations after exposure to gamma rays exhibited increases in the incidence of dicentric chromosomes but not of chromatid breaks, whereas unstable clones that survived 36 generations after exposure to (56)Fe particles exhibited increases in both chromatid and chromosome aberrations.

Mechanism of Action for Anti-Radiation Vaccine in Reducing the Biological Impact of High-Dose Irradiation

NASA Technical Reports Server (NTRS)

Maliev, Vladislav; Popov, Dmitri; Jones, Jeffrey A.; Casey, Rachael C.

2006-01-01

Ionizing radiation is a major health risk of long-term space travel, the biological consequences of which include genetic and oxidative damage. In this study, we propose an original mechanism by which high doses of ionizing radiation induce acute toxicity. We identified biological components that appear in the lymphatic vessels shortly after gamma irradiation. These radiation-induced toxins, which we have named specific radiation determinants (SRD), were generated in the irradiated tissues and then collected and circulated throughout the body via the lymph circulation and bloodstream. Depending on the type of SRD elicited, different syndromes of acute radiation sickness (ARS) were expressed. The SRDs were developed into a vaccine used to confer active immunity against acute radiation toxicity in immunologically naive animals. Animals that were pretreated with SRDs exhibited resistance to lethal doses of gamma radiation, as measured by increased survival times and survival rates. In comparison, untreated animals that were exposed to similar large doses of gamma radiation developed acute radiation sickness and died within days. This phenomenon was observed in a number of mammalian species. We partially analyzed the biochemical characteristics of the SRDs. The SRDs were large molecular weight (200-250 kDa) molecules that were comprised of a mixture of protein, lipid, carbohydrate, and mineral. Further analysis is required to further identify the SRD molecules and the biological mechanism by which the mediate the toxicity associated with acute radiation sickness. By doing so, we may develop an effective specific immunoprophylaxis as a countermeasure against the acute effects of ionizing radiation.

Evaluation of the Combined Effects of Gamma Radiation and High Dietary Iron on Peripheral Leukocyte Distribution and Function

NASA Technical Reports Server (NTRS)

Crucian, Brian E.; Morgan, Jennifer L. L.; Quiriarte, Heather A.; Sams, Clarence F.; Smith, Scott M.; Zwart, Sara R.

2011-01-01

NASA is concerned with the health risks to astronauts, particularly those risks related to radiation exposure. Both radiation and increased iron stores can independently increase oxidative damage, resulting in protein, lipid and DNA oxidation. Oxidative stress increases the risk of many health problems including cancer, cataracts, and heart disease. This study, a subset of a larger interdisciplinary investigation of the combined effect of iron overload on sensitivity to radiation injury, monitored immune parameters in the peripheral blood of rats subjected to gamma radiation, high dietary iron or both. Specific immune measures consisted of (A) peripheral leukocyte distribution; (B) plasma cytokine levels; (C) cytokine production profiles following whole blood stimulation of either T cells or monocytes.

Gamma radiation effects on siloxane-based additive manufactured structures

NASA Astrophysics Data System (ADS)

Schmalzer, Andrew M.; Cady, Carl M.; Geller, Drew; Ortiz-Acosta, Denisse; Zocco, Adam T.; Stull, Jamie; Labouriau, Andrea

2017-01-01

Siloxane-basedadditive manufactured structures prepared by the direct ink write (DIW) technology were exposed to ionizing irradiation in order to gauge radiolysis effects on structure-property relationships. These well-defined 3-D structures were subjected to moderate doses of gamma irradiation in an inert atmosphere and characterized by a suite of experimental methods. Changes in thermal, chemical, microstructure, and mechanical properties were evaluated by DSC, TGA, FT-IR, mass spectroscopy, EPR, solvent swelling, SEM, and uniaxial compressive load techniques. Our results demonstrated that 3-D structures made from aromatic-free siloxane resins exhibited hardening after being exposed to gamma radiation. This effect was accompanied by gas evolution, decreasing in crystallization levels, decreasing in solvent swelling and damage to the microstructure. Furthermore, long-lived radiation-induced radicals were not detected by EPR methods. Our results are consistent with cross-link formation being the dominant degradation mechanism over chain scission reactions. On the other hand, 3-D structures made from high phenyl content siloxane resins showed little radiation damage as evidenced by low off gassing.

Evaluation of phenolic compounds in maté ( Ilex paraguariensis) processed by gamma radiation

NASA Astrophysics Data System (ADS)

Furgeri, C.; Nunes, T. C. F.; Fanaro, G. B.; Souza, M. F. F.; Bastos, D. H. M.; Villavicencio, A. L. C. H.

2009-07-01

The radiation food processing has been demonstrating great effectiveness in the attack of pathogenic agents, while little compromising nutritional value and sensorial properties of foods. The maté ( Ilex paraguariensis), widely consumed product in South America, generally in the form of infusions with hot or cold water, calls of chimarrão or tererê, it is cited in literature as one of the best sources phenolic compounds. The antioxidants action of these constituent has been related to the protection of the organism against the free radicals, generated in alive, currently responsible for the sprouting of some degenerative illness as cancer, arteriosclerosis, rheumatic arthritis and cardiovascular clutters among others. The objective of that work was to evaluate the action of the processing for gamma radiation in phenolic compounds of tererê beverage in the doses of 0, 3, 5, 7 and 10 kGy. The observed results do not demonstrate significant alterations in phenolic compounds of tererê beverage processed by gamma radiation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahmud, Maznah; Radiation Processing Technology Division, Malaysian Nuclear Agency, 43000 Kajang, Selangor; Daik, Rusli

Poly(vinylpyrrolidone) (PVP)-crosslinked chitosan hydrogels were prepared by gamma radiation at various doses; 1, 3 5, 7, 10, 15, 20, 25 and 30kGy. Gamma radiation was used as a crosslinking tool which requires no chemical initiator, no heating process and need no purification step on the end products obtained. The hydrogel formulations were composed of 6% chitosan with average molecular weight (Mw) = 48 800 g/mol and 14% PVP with Mw = 10 000 g/mol in 2% lactic acid. Physical properties of hydrogels such as gel fraction and swelling property at pH 5.5 and pH 7.0 as well as syneresis activitymore » were determined. It was found that different radiation dose induces different effect on hydrogels’ network formed. Morphological study of hydrogels has been carried out by scanning electron microscope (SEM). From these preliminary evaluations, it can be concluded that gamma radiation is an effective tool for network development of hydrogels and it also induces enhancement on characteristics of hydrogels synthesized.« less

Gamma Radiation Reduced Toxicity of Azoxystrobin Tested on Artemia franciscana.

PubMed

Dvorak, P; Zdarsky, M; Benova, K; Falis, M; Tomko, M

2016-06-01

Fungicide azoxystrobin toxicity was monitored by means of a 96-h biotest with Artemia franciscana nauplius stages after exposure to solutions with concentrations of 0.2, 0.4, 0.6 and 0.8 mg L(-1) irradiated with (60)Co gamma radiation with doses of 1, 2.5, 5 and 10 kGy. The effects of ionization radiation on azoxystrobin toxicity were mainly manifested by a statistically significant reduction of lethality after 72- and 96-h exposure. A maximum reduction of lethality of 72 % was achieved using doses of 1-5 kGy for an azoxystrobin initial concentration of 0.4 mg L(-1) and after 72 h of exposure. At a 96-h exposure, a difference of lethal effects reached up to 70 % for a dose of 10 kGy. The observed effect of gamma ionizing radiation on azoxystrobin toxicity suggest that this approach can be applied as an alternative for a reduction of azoxystrobin residua in food.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marques, J.G.; Ramos, A.R.; Fernandes, A.C.

The behavior of electronic components and circuits under radiation is a concern shared by the nuclear industry, the space community and the high-energy physics community. Standard commercial components are used as much as possible instead of radiation hard components, since they are easier to obtain and allow a significant reduction of costs. However, these standard components need to be tested in order to determine their radiation tolerance. The Portuguese Research Reactor (RPI) is a 1 MW pool-type reactor, operating since 1961. The irradiation of electronic components and circuits is one area where a 1 MW reactor can be competitive, sincemore » the fast neutron fluences required for testing are in most cases well below 10{sup 16} n/cm{sup 2}. A program was started in 1999 to test electronics components and circuits for the LHC facility at CERN, initially using a dedicated in-pool irradiation device and later a beam line with tailored neutron and gamma filters. Neutron filters are essential to reduce the intensity of the thermal neutron flux, which does not produce significant defects in electronic components but produces unwanted radiation from activation of contacts and packages of integrated circuits and also of the printed circuit boards. In irradiations performed within the line-of-sight of the core of a fission reactor there is simultaneous gamma radiation which complicates testing in some cases. Filters can be used to reduce its importance and separate testing with a pure gamma radiation source can contribute to clarify some irradiation results. Practice has shown the need to introduce several improvements to the procedures and facilities over the years. We will review improvements done in the following areas: - Optimization of neutron and gamma filters; - Dosimetry procedures in mixed neutron / gamma fields; - Determination of hardness parameter and 1 MeV-equivalent neutron fluence; - Temperature measurement and control during irradiation; - Follow-up of reactor power operational fluctuations; - Study of gamma radiation effects only. The fission neutron spectrum can be limitative for some of the tests, as most neutrons are in the 1-2 MeV energy range. Significant progress has been made lately in compact neutron generators using D-D and D-T fusion reactions, achieving higher neutron fluxes and longer lifetime than previously available. The advantages of using compact neutron generators for testing of electronic components and circuits will be also discussed. (authors)« less

Effects of gamma irradiation on the grape vine moth, Lobesia botrana, eggs

NASA Astrophysics Data System (ADS)

Mansour, M.; Al-Attar, J.

2012-11-01

Eggs of the grape vine moth, Lobesia botrana (Denis and Schiffermuller), ranging in age from 1-24 to 73-96 h, were exposed, at 24 h intervals, to gamma radiation ranging from 25-600 Gy. The effects of gamma radiation on egg hatch, pupation, adult emergence, sex ratio and rate of development were examined. Results showed that the radiosensitivity of the grape vine moth eggs decreased with increasing age and increased with increasing radiation dose. Egg hatch in 1-24 h old eggs was significantly affected at 25 Gy and completely prevented at 100 Gy. At the age of 25-48 h, radiation sensitivity was only a little lower; egg hatch at 100 Gy was <1% and at 125 Gy no egg hatch was observed. Egg sensitivity to gamma irradiation decreased significantly in the 49-72 h age group; egg hatch was 66% at 100 Gy, and 500 Gy did not completely stop egg hatch (<1%). Eggs irradiated a few hours before egg hatch (73-96 h old) were the most resistant; 150 Gy had no significant effect on egg hatch and at 600 Gy over 33% of the eggs hatched. When pupation or adult emergence was used as a criterion for measuring effectiveness, however, the effects of gamma radiation were very severe. In the most resistant age group (73-96 h old), 150 Gy completely prevented pupation and adult emergence and all larvae resulting from eggs irradiated <49 h old died before pupation. In addition, the rate of development of immature stages resulting from irradiated eggs was negatively affected and sex ratio was skewed in favor of males.

DNA double-strand break repair of blood lymphocytes and normal tissues analysed in a preclinical mouse model: implications for radiosensitivity testing.

PubMed

Rübe, Claudia E; Grudzenski, Saskia; Kühne, Martin; Dong, Xiaorong; Rief, Nicole; Löbrich, Markus; Rübe, Christian

2008-10-15

Radiotherapy is an effective cancer treatment, but a few patients suffer severe radiation toxicities in neighboring normal tissues. There is increasing evidence that the variable susceptibility to radiation toxicities is caused by the individual genetic predisposition, by subtle mutations, or polymorphisms in genes involved in cellular responses to ionizing radiation. Double-strand breaks (DSB) are the most deleterious form of radiation-induced DNA damage, and DSB repair deficiencies lead to pronounced radiosensitivity. Using a preclinical mouse model, the highly sensitive gammaH2AX-foci approach was tested to verify even subtle, genetically determined DSB repair deficiencies known to be associated with increased normal tissue radiosensitivity. By enumerating gammaH2AX-foci in blood lymphocytes and normal tissues (brain, lung, heart, and intestine), the induction and repair of DSBs after irradiation with therapeutic doses (0.1-2 Gy) was investigated in repair-proficient and repair-deficient mouse strains in vivo and blood samples irradiated ex vivo. gammaH2AX-foci analysis allowed to verify the different DSB repair deficiencies; even slight impairments caused by single polymorphisms were detected similarly in both blood lymphocytes and solid tissues, indicating that DSB repair measured in lymphocytes is valid for different and complex organs. Moreover, gammaH2AX-foci analysis of blood samples irradiated ex vivo was found to reflect repair kinetics measured in vivo and, thus, give reliable information about the individual DSB repair capacity. gammaH2AX analysis of blood and tissue samples allows to detect even minor genetically defined DSB repair deficiencies, affecting normal tissue radiosensitivity. Future studies will have to evaluate the clinical potential to identify patients more susceptible to radiation toxicities before radiotherapy.

Measurements of the Martian Gamma/Neutron Spectra with MSL/RAD

NASA Astrophysics Data System (ADS)

Kohler, J.; Zeitlin, C. J.; Ehresmann, B.; Wimmer-Schweingruber, R. F.; Hassler, D.; Reitz, G.; Brinza, D.; Weigle, E.; Boettcher, S.; Burmeister, S.; Guo, J.; Martin-Garcia, C.; Boehm, E.; Posner, A.; Rafkin, S. C.; Kortmann, O.

2013-12-01

The Radiation Assessment Detector (RAD) onboard Mars Science Laboratory's rover curiosity measures the energetic charged and neutral particle spectra and the radiation dose rate on the Martian surface. An important factor for determining the biological impact of the Martian surface radiation is the specific contribution of neutrons, which possess a high biological effectiveness. In contrast to charged particles, neutrons and gamma rays are generally only measured indirectly. Their measurement is the result of a complex convolution of the incident particle spectrum with the measurement process. We apply an inversion method to calculate the gamma/neutron spectra from the RAD neutral particle measurements. Here we show first measurements of the Martian gamma/neutron spectra and compare them to theoretical predictions. We find that the shape of the gamma spectrum is very similar to the predicted one, but with a ~50% higher intensity. The measured neutron spectrum agrees well with prediction up to ~100 MeV, but shows a considerably increased intensity for higher energies. The measured neutron spectrum translates into a radiation dose rate of 25 μGy/day and a dose equivalent rate of 106 μSv/day. This corresponds to 10% of the total surface dose rate, and 15% of the biological relevant surface dose equivalent rate on Mars. Measuring the Martian neutron spectra is an essential step for determining the mutagenic influences to past or present life at or beneath the Martian surface as well as the radiation hazard for future human exploration, including the shielding design of a potential habitat. The contribution of neutrons to the dose equivalent increases considerably with shielding thickness, so our measurements provide an important figure to mitigate cancer risk.

Tripeptidyl peptidase II plays a role in the radiation response of selected primary cell types but not based on nuclear translocation and p53 stabilization.

PubMed

Firat, Elke; Tsurumi, Chizuko; Gaedicke, Simone; Huai, Jisen; Niedermann, Gabriele

2009-04-15

The giant cytosolic protease tripeptidyl peptidase II (TPPII) was recently proposed to play a role in the DNA damage response. Shown were nuclear translocation of TPPII after gamma-irradiation, lack of radiation-induced p53 stabilization in TPPII-siRNA-treated cells, and complete tumor regression in mice after gamma-irradiation when combined with TPPII-siRNA silencing or a protease inhibitor reported to inhibit TPPII. This suggested that TPPII could be a novel target for tumor radiosensitization and prompted us to study radiation responses using TPPII-knockout mice. Neither the sensitivity to total body irradiation nor the radiosensitivity of resting lymphoid cells, which both strongly depend on p53, was altered in the absence of TPPII. Functional integrity of p53 in TPPII-knockout cells is further shown by a proper G(1) arrest and by the accumulation of p53 and its transcriptional targets, p21, Bax, and Fas, on gamma-irradiation. Furthermore, we could not confirm radiation-induced nuclear translocation of TPPII. Nevertheless, after gamma-irradiation, we found slightly increased mitotic catastrophe of TPPII-deficient primary fibroblasts and increased apoptosis of TPPII-deficient activated CD8(+) T cells. The latter was accompanied by delayed resolution of the DNA double-strand break marker gammaH2AX. This could, however, be due to increased apoptotic DNA damage rather than reduced DNA damage repair. Our data do not confirm a role for TPPII in the DNA damage response based on nuclear TPPII translocation and p53 stabilization but nevertheless do show increased radiation-induced cell death of selected nontransformed cell types in the absence of the TPPII protease.

Evaluate an impact of incident alpha particle and gamma ray on human blood components: A comparison study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ismail, Asaad H.; Yaba, Sardar P.; Ismail, Haider J.

An impact of alpha and gamma irradiation on human blood components have been evaluated and compared for healthy blood samples (male and females). Irradiation dose and time of irradiation calibrated and considered as a main comparison factors. Density of blood components measured for each in vitro irradiation before and after irradiation for males and females. Survey radiation dosimeter (Inspector Exp) and nuclear track detectors type CR-39 used to evaluate exposure dose rate and incident density of alpha particles, respectively. Experiment results verified that the irradiation of blood makes ionizing of blood components, either alpha or gamma irradiation dose, and themore » impacts of ionizing radiation were relativity for WBC, RBC, and PLT. Limited irradiation doses of 1-5 μSv/hr considered as a low radiation dose of alpha and gamma radiation sources ({sup 226}Ra, and {sup 137}Cs). Density of alpha particles accumulated on the blood surface was 34 (alpha particle/cm{sup 2}) for selected dose of incident alpha particle. Optimum value of irradiation dose and time of irradiation were 5 μSv/hr and 4 second for males and females. On the other hands, the values of irradiation dose and time of irradiation were 2.1 μSv/hr and 2 second for males and females for gamma irradiation. Thus, present results demonstrated that densities of RBC and WBC cells are capable of inducing reproduction in vitro for both type of irradiation. (authors)« less

2D-DIGE-based proteome expression changes in leaves of rice seedlings exposed to low-level gamma radiation at Iitate village, Fukushima

PubMed Central

Hayashi, Gohei; Moro, Carlo F; Rohila, Jai Singh; Shibato, Junko; Kubo, Akihiro; Imanaka, Tetsuji; Kimura, Shinzo; Ozawa, Shoji; Fukutani, Satoshi; Endo, Satoru; Ichikawa, Katsuki; Agrawal, Ganesh Kumar; Shioda, Seiji; Hori, Motohide; Fukumoto, Manabu; Rakwal, Randeep

2015-01-01

The present study continues our previous research on investigating the biological effects of low-level gamma radiation in rice at the heavily contaminated Iitate village in Fukushima, by extending the experiments to unraveling the leaf proteome. 14-days-old plants of Japonica rice (Oryza sativa L. cv. Nipponbare) were subjected to gamma radiation level of upto 4 µSv/h, for 72 h. Following exposure, leaf samples were taken from the around 190 µSv/3 d exposed seedling and total proteins were extracted. The gamma irradiated leaf and control leaf (harvested at the start of the experiment) protein lysates were used in a 2-D differential gel electrophoresis (2D-DIGE) experiment using CyDye labeling in order to asses which spots were differentially represented, a novelty of the study. 2D-DIGE analysis revealed 91 spots with significantly different expression between samples (60 positive, 31 negative). MALDI-TOF and TOF/TOF mass spectrometry analyses revealed those as comprising of 59 different proteins (50 up-accumulated, 9 down-accumulated). The identified proteins were subdivided into 10 categories, according to their biological function, which indicated that the majority of the differentially expressed proteins consisted of the general (non-energy) metabolism and stress response categories. Proteome-wide data point to some effects of low-level gamma radiation exposure on the metabolism of rice leaves. PMID:26451896

Modeling background radiation using geochemical data: A case study in and around Cameron, Arizona.

PubMed

Marsac, Kara E; Burnley, Pamela C; Adcock, Christopher T; Haber, Daniel A; Malchow, Russell L; Hausrath, Elisabeth M

2016-12-01

This study compares high resolution forward models of natural gamma-ray background with that measured by high resolution aerial gamma-ray surveys. The ability to predict variations in natural background radiation levels should prove useful for those engaged in measuring anthropogenic contributions to background radiation for the purpose of emergency response and homeland security operations. The forward models are based on geologic maps and remote sensing multi-spectral imagery combined with two different sources of data: 1) bedrock geochemical data (uranium, potassium and thorium concentrations) collected from national databases, the scientific literature and private companies, and 2) the low spatial resolution NURE (National Uranium Resource Evaluation) aerial gamma-ray survey. The study area near Cameron, Arizona, is located in an arid region with minimal vegetation and, due to the presence of abandoned uranium mines, was the subject of a previous high resolution gamma-ray survey. We found that, in general, geologic map units form a good basis for predicting the geographic distribution of the gamma-ray background. Predictions of background gamma-radiation levels based on bedrock geochemical analyses were not as successful as those based on the NURE aerial survey data sorted by geologic unit. The less successful result of the bedrock geochemical model is most likely due to a number of factors including the need to take into account the evolution of soil geochemistry during chemical weathering and the influence of aeolian addition. Refinements to the forward models were made using ASTER visualizations to create subunits of similar exposure rate within the Chinle Formation, which contains multiple lithologies and by grouping alluvial units by drainage basin rather than age. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Modeling background radiation using geochemical data: A case study in and around Cameron, Arizona

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marsac, Kara E.; Burnley, Pamela C.; Adcock, Christopher T.

Here, this study compares high-resolution forward models of natural gamma-ray background with that measured by high resolution aerial gamma-ray surveys. The ability to predict variations in natural background radiation levels should prove useful for those engaged in measuring anthropogenic contributions to background radiation for the purpose of emergency response and homeland security operations. The forward models are based on geologic maps and remote sensing multi-spectral imagery combined with two different sources of data: 1) bedrock geochemical data (uranium, potassium and thorium concentrations) collected from national databases, the scientific literature and private companies, and 2) the low spatial resolution NURE (Nationalmore » Uranium Resource Evaluation) aerial gamma-ray survey. The study area near Cameron, Arizona, is located in an arid region with minimal vegetation and, due to the presence of abandoned uranium mines, was the subject of a previous high resolution gamma-ray survey. We found that, in general, geologic map units form a good basis for predicting the geographic distribution of the gamma-ray background. Predictions of background gamma-radiation levels based on bedrock geochemical analyses were not as successful as those based on the NURE aerial survey data sorted by geologic unit. The less successful result of the bedrock geochemical model is most likely due to a number of factors including the need to take into account the evolution of soil geochemistry during chemical weathering and the influence of aeolian addition. Refinements to the forward models were made using ASTER visualizations to create subunits of similar exposure rate within the Chinle Formation, which contains multiple lithologies and by grouping alluvial units by drainage basin rather than age.« less

Modeling background radiation using geochemical data: A case study in and around Cameron, Arizona

DOE PAGES

Marsac, Kara E.; Burnley, Pamela C.; Adcock, Christopher T.; ...

2016-09-16

Here, this study compares high-resolution forward models of natural gamma-ray background with that measured by high resolution aerial gamma-ray surveys. The ability to predict variations in natural background radiation levels should prove useful for those engaged in measuring anthropogenic contributions to background radiation for the purpose of emergency response and homeland security operations. The forward models are based on geologic maps and remote sensing multi-spectral imagery combined with two different sources of data: 1) bedrock geochemical data (uranium, potassium and thorium concentrations) collected from national databases, the scientific literature and private companies, and 2) the low spatial resolution NURE (Nationalmore » Uranium Resource Evaluation) aerial gamma-ray survey. The study area near Cameron, Arizona, is located in an arid region with minimal vegetation and, due to the presence of abandoned uranium mines, was the subject of a previous high resolution gamma-ray survey. We found that, in general, geologic map units form a good basis for predicting the geographic distribution of the gamma-ray background. Predictions of background gamma-radiation levels based on bedrock geochemical analyses were not as successful as those based on the NURE aerial survey data sorted by geologic unit. The less successful result of the bedrock geochemical model is most likely due to a number of factors including the need to take into account the evolution of soil geochemistry during chemical weathering and the influence of aeolian addition. Refinements to the forward models were made using ASTER visualizations to create subunits of similar exposure rate within the Chinle Formation, which contains multiple lithologies and by grouping alluvial units by drainage basin rather than age.« less

A FTIR/chemometrics approach to characterize the gamma radiation effects on iodine/epoxy-paint interactions in Nuclear Power Plants.

PubMed

Colombani, Juliette; Chauvet, Elodie; Amat, Sandrine; Dupuy, Nathalie; Gigmes, Didier

2017-04-01

The effects of radiation on polymeric materials are a topic of concern in a wide range of industries including the sterilization, and the nuclear power industry. While much work has concentrated on systems like polyolefins that are radiation sterilized, some work has been done on epoxy systems. The epoxy system studied is an epoxy/amine paint which is representative of the paint that covers the inner surfaces of the French nuclear reactor containment buildings. In case of a severe accident on a Nuclear Power Plant, fission products can be released from the nuclear fuel to the reactor containment building. Among them, volatile iodine (I 2 ) can be produced and can interact with the epoxy-paint. This paint is also subjected to gamma radiation damages (due to the high dose in the containment coming from radionuclides released from the fuel). So the epoxy-paint studied was exposed to gamma radiation under air atmosphere after being loaded with I 2 or not. The aim of this study is to characterize by FTIR spectroscopy the iodine-paint interactions, then to identify the radiation damages on the epoxy-paint, and to check their effects on these iodine-paint interactions. This work shows the potential of multi-block analysis method (ANOVA-PCA and COMDIM = AComDim) for such a study as it allows to identify the nature of iodine/epoxy-paint interactions and to characterize the gamma radiation damages on the epoxy-paint. AComDim method conduces to the extraction of Common Components to different tables and highlights factors of influence and their interactions. Copyright © 2017 Elsevier B.V. All rights reserved.

Gamma Radiation Induces Micronucleated Reticulocytes in 3-D Bone Marrow Bioreactors in Vitro

PubMed Central

Sun, Hongliang; Dertinger, Stephen D.; Hyrien, Ollivier; David Wu, J. H.; Chen, Yuhchyau

2009-01-01

Radiation injury to the bone marrow is potentially lethal due to the potent DNA-damaging effects on cells of the hematopoietic system, including bone marrow stem cell, progenitor, and the precursor cell populations. Investigation of radiation genotoxic effects on bone marrow progenitor/precursor cells has been challenged by the lack of optimal in vitro surrogate organ culture systems, and the overall difficulty to sustain lineage-specific proliferation and differentiation of hematopoiesis in vitro. We report the investigation of radiation genotoxic effects in bone marrow cultures of C57Bl/6 mice established in 3-D bioreactors, which sustain long-term bone marrow cultures. For these studies, genotoxicity is measured by the induction of micronucleated reticulocytes (MN-RET). The kinetics and dose-response relationship of MN-RET induction in response to gamma-radiation of bioreactor-maintained bone marrow cultures are presented. Our data showed that 3-D long-term bone marrow cultures had sustained erythropoiesis capable of generating reticulocytes up to 8 weeks. The peak time-interval of viable cell output and percentage of reticulocytes increased steadily and reached the initial peak between the 14th to 21st days after inoculations. This was followed by a rebound or staying relatively constant until week 8. The percentage of MN-RET reached the maximum between 24 and 32 hours post 1 Gy gamma-ray. There was a near linear MN-RET induction by gamma radiation from 0 Gy to 1.0 Gy, followed by an attenuated increase to 1.5 – 2.0 Gy. The MN-RET response showed a downtrend beyond 2 Gy. Our data suggest that bone marrow culture in the 3-D bioreactor may be a useful organ culture system for the investigation of radiation genotoxic effect in vitro. PMID:19786117

Gamma ray shielding and structural properties of Bi2O3-PbO-B2O3-V2O5 glass system

NASA Astrophysics Data System (ADS)

Kaur, Kulwinder; Singh, K. J.; Anand, Vikas

2014-04-01

The present work has been undertaken to evaluate the applicability of Bi2O3-PbO-B2O3-V2O5 glass system as gamma ray shielding material. Gamma ray mass attenuation coefficient has been determined theoretically using WinXcom computer software developed by National Institute of Standards and Technology. A meaningful comparison of their radiation shielding properties has been made in terms of their half value layer parameter with standard radiation shielding concrete 'barite'. Structural properties of the prepared glass system have been investigated in terms of XRD and FTIR techniques in order to check the possibility of their commercial utility as alternate to conventional concrete for gamma ray shielding applications.

Effects of chronic external gamma irradiation on growth and reproductive success of Daphnia magna.

PubMed

Gilbin, Rodolphe; Alonzo, Frédéric; Garnier-Laplace, Jacqueline

2008-01-01

Aquatic invertebrates (water flea Daphnia magna) were exposed to low dose rates of external gamma radiation (from 0.4 to 31mGyh(-1)) over a 23-day period (i.e. 5 broods). Gamma radiation caused changes in neither survival nor somatic growth. Mass-specific respiration rate was significantly lower at 31mGyh(-1) than in the control. Reproduction was affected through early release and reduced size of broods after 15 days of exposure at 31mGyh(-1) (broods 3-5), resulting in a 21% fecundity decrease at 31mGyh(-1) compared to the control. A decreased resistance of neonates to starvation was observed in relation to dose rates. Possible mechanisms of gamma radiotoxicity for daphnid reproduction and implications for radioprotection are discussed.

Multi-wavelength observations of the flaring gamma-ray blazar 3C 66A in 2008 October

DOE PAGES

Abdo, A. A.; Ackermann, M.; Ajello, M.; ...

2010-12-14

We report that Tthe BL Lacertae object 3C 66A was detected in a flaring state by the Fermi Large Area Telescope (LAT) and VERITAS in 2008 October. In addition to these gamma-ray observations, F-GAMMA, GASP-WEBT, PAIRITEL, MDM, ATOM, Swift, and Chandra provided radio to X-ray coverage. The available light curves show variability and, in particular, correlated flares are observed in the optical and Fermi-LAT gamma-ray band. The resulting spectral energy distribution can be well fitted using standard leptonic models with and without an external radiation field for inverse Compton scattering. It is found, however, that only the model with anmore » external radiation field can accommodate the intra-night variability observed at optical wavelengths.« less

Survival of Mice with Gastrointestinal Acute Radiation Syndrome through Control of Bacterial Translocation.

PubMed

Suzuki, Fujio; Loucas, Bradford D; Ito, Ichiaki; Asai, Akira; Suzuki, Sumihiro; Kobayashi, Makiko

2018-07-01

Macrophages (Mϕ) with the M2b phenotype (Pheno2b-Mϕ) in bacterial translocation sites have been described as cells responsible for the increased susceptibility of mice with gastrointestinal acute radiation syndrome to sepsis caused by gut bacteria. In this study, we tried to reduce the mortality of mice exposed to 7-10 Gy of gamma rays by controlling Pheno2b-Mϕ polarization in bacterial translocation sites. MicroRNA-222 was induced in association with gamma irradiation. Pheno2b-Mϕ polarization was promoted and maintained in gamma-irradiated mice through the reduction of a long noncoding RNA growth arrest-specific transcript 5 (a CCL1 gene silencer) influenced by this microRNA. Therefore, the host resistance of 7-9-Gy gamma-irradiated mice to sepsis caused by bacterial translocation was improved after treatment with CCL1 antisense oligodeoxynucleotide. However, the mortality of 10-Gy gamma-irradiated mice was not alleviated by this treatment. The crypts and villi in the ileum of 10-Gy gamma-irradiated mice were severely damaged, but these were markedly improved after transplantation of intestinal lineage cells differentiated from murine embryonic stem cells. All 10-Gy gamma-irradiated mice given both of the oligodeoxynucleotide and intestinal lineage cells survived, whereas all of the same mice given either of them died. These results indicate that high mortality rates of mice irradiated with 7-10 Gy of gamma rays are reducible by depleting CCL1 in combination with the intestinal lineage cell transplantation. These findings support the novel therapeutic possibility of victims who have gastrointestinal acute radiation syndrome for the reduction of their high mortality rates. Copyright © 2018 by The American Association of Immunologists, Inc.

Impact of radiation treatment on chemical, biochemical and sensory properties, and microbiological quality of mackerel

NASA Astrophysics Data System (ADS)

Pinter, Nino; Maltar-Strmečki, Nadica; Kozačinski, Lidija; Njari, Bela; Cvrtila Fleck, Željka

2015-12-01

The effect of gamma radiation on shelf-life of mackerel (Scomber scombrus) was studied. Changes in raw fish stored at 4 °C were investigated simultaneously, by performing sensory evaluation, chemical analysis (pH value and NH3 concentration), and biochemical analyses of histamine concentration and microbiological quality. Analyses showed that preservation by gamma irradiation prolonged the freshness and sustainability without any unintended sensory changes. Furthermore, increasing the dose during the 10 days of storage considerably reduced the concentration of histamine, but only slightly reduced the concentration of ammonia (NH3). Bacterial examinations showed that gamma radiation decreased the total number of bacteria. Our results indicated that the shelf-life of mackerel stored at 4 °C can be prolonged by irradiation with a dose of 3 kGy.

Soda-lime-silica glass for radiation dosimetry.

PubMed

Ezz-Eldin, F M; Abdel-Rehim, F; Abdel-Azim, A A; Ahmed, A A

1994-07-01

The color developed in a commercially available soda-lime-silica glass when subjected to gamma-irradiation and the stability of such radiation-induced color were studied to test its sensitivity to small doses of gamma-rays (0.0-27 kGy). After irradiation, two absorption bands developed at 400 and 620 nm. The former band exhibited a stronger absorption than the later one. The intensity of both bands showed a gradual increase with increasing irradiation dose and a gradual decrease with increasing fading time after irradiation. The development of these bands is associated with the generation of defects at nonbridging oxygen atoms in the glass lattice and hole centers. The results obtained suggest that this glass simulated the Z of compact bone in terms of gamma rays absorption properties over broad radiation spectra (0.1 to 10 MeV).

Environmental microbiology as related to planetary quarantine

NASA Technical Reports Server (NTRS)

Pflug, I. J.

1972-01-01

The experimental design of a study to evaluate the effect of different cleaning methods and storage conditions on the dry heat resistance of Bacillus subtilis var. niger spores is described and the results for the first evaluation are reported. Specifically, the synergistic effect which occurs when spores are subjected simultaneously to dry heat and gamma radiation so as to be able to specify thermoradiation sterilization cycles was investigated. Attempts were made to understand the underlying mechanism(s) that lead to spore death from this combination of stresses. Data cover: (1) the survival of spores on surfaces at various temperatures in a precisely controlled environmental system, (2) the rate of destruction of these spores at ambient temperature when subjected to gamma radiation, and (3) the rate of destruction of spores when they are subjected to combined gamma radiation and thermal stresses.

Optically stimulated luminescence of natural NaCl mineral from Dead Sea exposed to gamma radiation.

PubMed

Roman-Lopez, J; Piña López, Y I; Cruz-Zaragoza, E; Marcazzó, J

2018-08-01

In this work, the continuous wave - optically stimulated luminescence (CW-OSL) emissions of natural salt minerals, collected from Dead Sea in summer of 2015, were studied. The CW-OSL dose response of natural salt showed a linear range between 0.5Gy and 10Gy of gamma radiation of 60 Co. Samples exposed at 3Gy exhibited good repeatability with a variation coefficient of 4.6%. The CW-OSL response as function of the preheating temperature (50-250°C) was analyzed. An increase of 15% of the CW-OSL response was observed in NaCl samples during storage period of 336h. The results showed that the natural Dead Sea salt minerals could be applied as natural dosimeter of gamma radiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of Panax ginseng saponins and Eleutherococcus senticosus on survival of cultured mammalian cells after ionizing radiation.

PubMed

Ben-Hur, E; Fulder, S

1981-01-01

Panax ginseng saponin and Eleutherococcus senticosus extract were applied to cells in culture in order to assess the effect of these substances on resistance to gamma-irradiation. Eleutherococcus was slightly radio protective. However, ginseng saponin at a dose of 10 microgram/ml was significantly radioprotective (Do = 2.25 Gy) compared to control (Do = 1.80 Gy) when it was present prior to gamma-irradiation. It enhanced radiation response if it was also present for 4-6 hours after gamma-irradiation (Do = 1.10 Gy). Ginseng-treated cells made 30% less RNA and 14% more protein during a 1 hour pulse of labeled intermediates. The cells were morphologically altered. It is concluded that ginseng saponin can increase radiation resistance. The effect is indirect, due to alterations in cell physiology rather than DNA repair processes.

Airborne gamma radiation soil moisture measurements over short flight lines

NASA Technical Reports Server (NTRS)

Peck, Eugene L.; Carrol, Thomas R.; Lipinski, Daniel M.

1990-01-01

Results are presented on airborne gamma radiation measurements of soil moisture condition, carried out along short flight lines as part of the First International Satellite Land Surface Climatology Project Field Experiment (FIFE). Data were collected over an area in Kansas during the summers of 1987 and 1989. The airborne surveys, together with ground measurements, provide the most comprehensive set of airborne and ground truth data available in the U.S. for calibrating and evaluating airborne gamma flight lines. Analysis showed that, using standard National Weather Service weights for the K, Tl, and Gc radiation windows, the airborne soil moisture estimates for the FIFE lines had a root mean square error of no greater than 3.0 percent soil moisture. The soil moisture estimates for sections having acquisition time of at least 15 sec were found to be reliable.

Effects of gamma irradiations on reactive pulsed laser deposited vanadium dioxide thin films

NASA Astrophysics Data System (ADS)

Madiba, I. G.; Émond, N.; Chaker, M.; Thema, F. T.; Tadadjeu, S. I.; Muller, U.; Zolliker, P.; Braun, A.; Kotsedi, L.; Maaza, M.

2017-07-01

Vanadium oxide films are considered suitable coatings for various applications such as thermal protective coating of small spacecrafts because of their thermochromic properties. While in outer space, such coating will be exposed to cosmic radiations which include γ-rays. To study the effect of these γ-rays on the coating properties, we have deposited vanadium dioxide (VO2) films on silicon substrates and subjected them to extensive γ-irradiations with typical doses encountered in space missions. The prevalent crystallographic phase after irradiation remains the monoclinic VO2 phase but the films preferential orientation shifts to lower angles due to the presence of disordered regions caused by radiations. Raman spectroscopy measurements also evidences that the VO2 structure is slightly affected by gamma irradiation. Indeed, increasing the gamma rays dose locally alters the crystalline and electronic structures of the films by modifying the V-V inter-dimer distance, which in turns favours the presence of the VO2 metallic phase. From the XPS measurements of V2p and O1s core level spectra, an oxidation of vanadium from V4+ towards V5+ is revealed. The data also reveal a hydroxylation upon irradiation which is corroborated by the vanishing of a low oxidation state peak near the Fermi energy in the valence band. Our observations suggest that gamma radiations induce the formation of Frenkel pairs. Moreover, THz transmission measurements show that the long range structure of VO2 remains intact after irradiation whilst the electrical measurements evidence that the coating resistivity decreases with gamma irradiation and that their transition temperature is slightly reduced for high gamma ray doses. Even though gamma rays are only one of the sources of radiations that are encountered in space environment, these results are very promising with regards to the potential of integration of such VO2 films as a protective coating for spacecrafts.

Spectral measurements of direct and scattered gamma radiation at a boiling-water reactor site

NASA Astrophysics Data System (ADS)

Block, R. C.; Preiss, I. L.; Ryan, R. M.; Vargo, G. J.

1990-12-01

Quantitative surveys of direct and scattered gamma radiation emitted from the steam-power conversion systems of a boiling-water reactor and other on-site radiation sources were made using a directionally shielded HPGe gamma spectrometry system. The purpose of this study was to obtain data on the relative contributions and energy distributions of direct and scattered gamma radiation in the site environs. The principal radionuclide of concern in this study is 16N produced by the 16O(n,p) 16N reaction in the reactor coolant. Due to changes in facility operation resulting from the implementation of hydrogen water chemistry (HWC), the amount of 16N transported from the reactor to the main steam system under full power operation is excepted to increase by a factor of 1.2 to 5.0. This increase in the 16N source term in the nuclear steam must be considered in the design of new facilities to be constructed on site as well as the evaluation of existing facilities with repect to ALARA (As Low As Reasonably Achievable) dose limits in unrestricted areas. This study consisted of base-line measurements taken under normal BWR chemistry conditions in October, 1987 and a corresponding set taken under HWC conditions in July, 1988. Ground-level and elevated measurements, corresponding to second-story building height, were obtained. The primary conclusion of this study is that direct radiation from the steam-power conversion system is the predominant source of radiation in the site environs of this reactor and that air scattering (i.e. skyshine) does not appear to be significant.

Radiation damage of all-silica fibers in the UV region

NASA Astrophysics Data System (ADS)

Gombert, Joerg; Ziegler, M.; Assmus, J.; Klein, Karl-Friedrich; Nelson, Gary W.; Clarkin, James P.; Pross, H.; Kiefer, J.

1999-04-01

Since several years, UVI-fibers having higher solarization- resistance are well known stimulating new fiber-optic applications in the UV-region below 250 nm. Besides the description of the improved transmission properties of UV- light from different UV-sources, the mechanisms of improvement have been discussed in detail. The UV-defects, mainly the E'- center with the UV-absorption band around 215 nm, were passivated by using hydrogen-doping. Besides DUV-light, ionizing radiation like Gamma-radiation or X-rays can create similar defects in the UV-region. In the past, the radiation- damage in the UV-region was studied on silica bulk samples: again, E'-centers were generated. Up to now, no UV- transmission through a 1 m long fiber during or after Gamma- radiation had been observed. However, the hydrogen in the UVI- fibers behaves the same for Gamma-irradiation, leading to a passivation of the radiation-induced defects and an improved transmission in the UV-C region below 250 nm. On this report, the influence of total dose and fiber diameter on the UV- damage after irradiation will be described and discussed. In addition, we will include annealing studies, with and without UV-light. Based on our results, the standard process of Gamma- sterilization with a total dose of approx. 2 Mrad can be used for UVI-fibers resulting in a good UV-transmission below 320 nm. Excimer-laser light at 308 nm (XeCl) and 248 nm (KrF) and deuterium-lamp light with the full spectrum starting at 200 nm can also be transmitted.

Dose responses for adaption to low doses of (60)Co gamma rays and (3)H beta particles in normal human fibroblasts.

PubMed

Broome, E J; Brown, D L; Mitchel, R E J

2002-08-01

The dose response for adaption to radiation at low doses was compared in normal human fibroblasts (AG1522) exposed to either (60)Co gamma rays or (3)H beta particles. Cells were grown in culture to confluence and exposed at either 37 degrees C or 0 degrees C to (3)H beta-particle or (60)Co gamma-ray adapting doses ranging from 0.1 mGy to 500 mGy. These cells, and unexposed control cells, were allowed to adapt during a fixed 3-h, 37 degrees C incubation prior to a 4-Gy challenge dose of (60)Co gamma rays. Adaption was assessed by measuring micronucleus frequency in cytokinesis-blocked, binucleate cells. No adaption was detected in cells exposed to (60)Co gamma radiation at 37 degrees C after a dose of 0.1 mGy given at a low dose rate or to 500 mGy given at a high dose rate. However, low-dose-rate exposure (1-3 mGy/min) to any dose between 1 and 500 mGy from either radiation, delivered at either temperature, caused cells to adapt and reduced the micronucleus frequency that resulted from the subsequent 4-Gy exposure. Within this dose range, the magnitude of the reduction was the same, regardless of the dose or radiation type. These results demonstrate that doses as low as (on average) about one track per cell (1 mGy) produce the same maximum adaptive response as do doses that deposit many tracks per cell, and that the two radiations were not different in this regard. Exposure at a temperature where metabolic processes, including DNA repair, were inactive (0 degrees C) did not alter the result, indicating that the adaptive response is not sensitive to changes in the accumulation of DNA damage within this range. The results also show that the RBE for low doses of tritium beta-particle radiation is 1, using adaption as the end point.

Guide to U.S. Atmospheric Nuclear Weapon Effects Data

DTIC Science & Technology

1993-12-01

biological warfare agents, and radiation dosimeters . XRD- 163 identifies the test location of each 4-6 biological sample. Reports containing the results...along with position of the animals at the time of the detonation. Vycor Glass Gamma Ray Dosimeters XRD-176 A rugged new dosimeter capable of measuring...gamma doses on animals exposed to high levels of radiation was employed during Able. Dosimeter readings, locations, and animal condition are reported

EFFECT OF $gamma$-RAYS ON THE BIOCHEMICAL PROPERTIES OF WHEAT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sosedov, N.I.; Vakar, A.B.

1963-01-01

Progress in the Soviet Union on radiation effects on biochemical and baking properties of wheat is reported. biochemical analysis of the various forms of nitrogenous substances in wheat with moisture contents of 13.4 and 25.8 percent after irradiation with gamma rays shows that the radiation effects on giuten are dependent upon moisture content. Gluten in dry grain exposed to gamma rays became weak, inelastic, and too extensile while that in moist grain became excessively stiff with consequent loss of extensibility and cohesion. In dry irradiated grain increases were found in protein substance solubility and protein splitting, whereas in irradiated grainmore » with a higher moisture content, there was less protein splitting and solubility of protein substances was reduced. When the moisture content was 16.4-percent, radintion damage was least, the two opposite sets of deleterious effects being somewhat (not completely) balanced. The different effects of the same radiation doses on moist and dry grain was corfirmed by spectrophotometric examination. Large gamma doses increase the quantity of reducing sugars and decrease the starch content. These carbohydrate changes are more pronounced with dry than with moist grain. It is concluded that with present knowledge and techniques the method of radiational treatment of grain cannot be recommended for practical use. (H.M.G.)« less

Enhancement of natural background gamma-radiation dose around uranium microparticles in the human body

PubMed Central

Pattison, John E.; Hugtenburg, Richard P.; Green, Stuart

2010-01-01

Ongoing controversy surrounds the adverse health effects of the use of depleted uranium (DU) munitions. The biological effects of gamma-radiation arise from the direct or indirect interaction between secondary electrons and the DNA of living cells. The probability of the absorption of X-rays and gamma-rays with energies below about 200 keV by particles of high atomic number is proportional to the third to fourth power of the atomic number. In such a case, the more heavily ionizing low-energy recoil electrons are preferentially produced; these cause dose enhancement in the immediate vicinity of the particles. It has been claimed that upon exposure to naturally occurring background gamma-radiation, particles of DU in the human body would produce dose enhancement by a factor of 500–1000, thereby contributing a significant radiation dose in addition to the dose received from the inherent radioactivity of the DU. In this study, we used the Monte Carlo code EGSnrc to accurately estimate the likely maximum dose enhancement arising from the presence of micrometre-sized uranium particles in the body. We found that although the dose enhancement is significant, of the order of 1–10, it is considerably smaller than that suggested previously. PMID:19776147

Radiation inactivation of Paenibacillus larvae and sterilization of American Foul Brood (AFB) infected hives using Co-60 gamma rays.

PubMed

De Guzman, Zenaida M; Cervancia, Cleofas R; Dimasuay, Kris Genelyn B; Tolentino, Mitos M; Abrera, Gina B; Cobar, Ma Lucia C; Fajardo, Alejandro C; Sabino, Noel G; Manila-Fajardo, Analinda C; Feliciano, Chitho P

2011-10-01

The effectiveness of gamma radiation in inactivating the Philippine isolate of Paenibacillus larvae was investigated. Spores of P. larvae were irradiated at incremental doses (0.1, 0.2, 0.4, 0.8 and 1.6 kGy) of gamma radiation emitted by a ⁶⁰Co source. Surviving spores were counted and used to estimate the decimal reduction (D₁₀) value. A dose of 0.2 kGy was sufficient to inactivate 90% of the total recoverable spores from an initial count of 10⁵- 9 × 10³ spores per glass plate. The sterilizing effect of high doses of gamma radiation on the spores of P. larvae in infected hives was determined. In this study, a minimum dose (D(min)) of 15 kGy was tested. Beehives with sub-clinical infections of AFB were irradiated and examined for sterility. All the materials were found to be free of P. larvae indicating its susceptibility to γ-rays. After irradiation, there were no visible changes in the physical appearance of the hives' body, wax and frames. Thus, a dose of 15 kGy is effective enough for sterilization of AFB-infected materials. Copyright © 2011 Elsevier Ltd. All rights reserved.

SEE induced in SRAM operating in a superconducting electron linear accelerator environment

NASA Astrophysics Data System (ADS)

Makowski, D.; Mukherjee, Bhaskar; Grecki, M.; Simrock, Stefan

2005-02-01

Strong fields of bremsstrahlung photons and photoneutrons are produced during the operation of high-energy electron linacs. Therefore, a mixed gamma and neutron radiation field dominates the accelerators environment. The gamma radiation induced Total Ionizing Dose (TID) effect manifests the long-term deterioration of the electronic devices operating in accelerator environment. On the other hand, the neutron radiation is responsible for Single Event Effects (SEE) and may cause a temporal loss of functionality of electronic systems. This phenomenon is known as Single Event Upset (SEU). The neutron dose (KERMA) was used to scale the neutron induced SEU in the SRAM chips. Hence, in order to estimate the neutron KERMA conversion factor for Silicon (Si), dedicated calibration experiments using an Americium-Beryllium (241Am/Be) neutron standard source was carried out. Single Event Upset (SEU) influences the short-term operation of SRAM compared to the gamma induced TID effect. We are at present investigating the feasibility of an SRAM based real-time beam-loss monitor for high-energy accelerators utilizing the SEU caused by fast neutrons. This paper highlights the effects of gamma and neutron radiations on Static Random Access Memory (SRAM), placed at selected locations near the Superconducting Linear Accelerator driving the Vacuum UV Free Electron Laser (VUVFEL) of DESY.

Induction of a Radio-Adaptive Response by Low-dose Gamma Irradiation in Mouse Cardiomyocytes

NASA Technical Reports Server (NTRS)

Westby, Christian M.; Seawright, John W.; Wu, Honglu

2011-01-01

One of the most significant occupational hazards to an astronaut is the frequent exposure to radiation. Commonly associated with increased risk for cancer related morbidity and mortality, radiation is also known to increase the risk for cardiovascular related disorders including: pericarditis, hypertension, and heart failure. It is believed that these radiation-induced disorders are a result of abnormal tissue remodeling. It is unknown whether radiation exposure promotes remodeling through fibrotic changes alone or in combination with programmed cell death. Furthermore, it is not known whether it is possible to mitigate the hazardous effects of radiation exposure. As such, we assessed the expression and mechanisms of radiation-induced tissue remodeling and potential radio-adaptive responses of p53-mediated apoptosis and fibrosis pathways along with markers for oxidative stress and inflammation in mice myocardium. 7 week old, male, C57Bl/6 mice were exposed to 6Gy (H) or 5cGy followed 24hr later with 6Gy (LH) 137Cs gamma radiation. Mice were sacrificed and their hearts extirpated 4, 24, or 72hr after final irradiation. Real Time - Polymerase Chain Reaction was used to evaluate target genes. Apoptotic genes Bad and Bax, pro-cell survival genes Bcl2 and Bcl2l2, fibrosis gene Vegfa, and oxidative stress genes Sod2 and GPx4 showed a reduced fold regulation change (Bad,-6.18; Bax,-6.94; Bcl2,-5.09; Bcl2l2,-4.03; Vegfa, -11.84; Sod2,-5.97; GPx4*,-28.72; * = Bonferroni adjusted p-value < or = 0.003) 4hr after H, but not after 4hr LH compared to control. Other p53-mediated apoptosis genes Casp3, Casp9, Trp53, and Myc exhibited down-regulation but did not achieve a notable level of significance 4hr after H. 24hr after H, genetic down-regulation was no longer present compared to 24hr control. These data suggest a general reduction in genetic expression 4hrs after a high dose of gamma radiation. However, pre-exposure to 5cGy gamma radiation appears to facilitate a radio-adaptive response that mitigates the reduction in genetic expression associated with single high-dose gamma radiation exposure. This radio-adaptive response may serve as a potential countermeasure to radiation-induced myocardial remodeling and preserve the cardiovascular health of astronauts; thus, reducing the risks of human space exploration.

Method and Apparatus for Measuring Radiation Quantities

DOEpatents

Roberts, N O

1955-01-25

This patent application describes a compact dosimeter for measuring X-ray and gamma radiation by the use of solutions which undergo a visible color change upon exposure to a predetermined quantity of radiation.

Mutant quantity and quality in mammalian cells (A{sub L}) exposed to cesium-137 gamma radiation: Effect of caffeine

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGuinness, S.M.; Shibuya, M.L.; Ueno, A.M.

1995-06-01

We examined the effect of caffeine (1,3,7-trimethylxanthine) on the quantity and quality of mutations in cultured mammalian A{sub L} human-hamster hybrid cells exposed to {sup 137}Cs {gamma} radiation. At a dose (1.5 mg/ml for 16 h) that reduced the plating efficiency (PE) by 20%, caffeine was not itself a significant mutagen, but it increased by approximately twofold the slope of the dose-response curve for induction of S1{sup {minus}} mutants by {sup 137}Cs {gamma} radiation. Molecular analysis of 235 S1{sup {minus}} mutants using a series of DNA probes mapped to the human chromosome 11 in the A{sub L} hybrid cells revealedmore » that 73 to 85% of the mutations in unexposed cells and in cells treated with caffeine alone, {sup 137}Cs {gamma} rays alone or {sup 137}Cs {gamma} rays plus caffeine were large deletions involving millions of base pairs of DNA. Most of these deletions were contiguous with the region of the MIC1 gene at 11p13 that encodes the S1 cell surface antigen. In other mutants that had suffered multiple marker loss, the deletions were intermittent along chromosome 11. These {open_quotes}complex{close_quotes} mutations were rare for {sup 137}Cs {gamma} irradiation (1/63 = 1.5%) but relatively prevalent (23-50%) for other exposure conditions. Thus caffeine appears to alter both the quantity and quality of mutations induced by {sup 137}Cs {gamma} irradiation. 62 refs., 3 figs., 3 tabs.« less

EGRET upper limits to the high-energy gamma-ray emission from the millisecond pulsars in nearby globular clusters

NASA Technical Reports Server (NTRS)

Michelson, P. F.; Bertsch, D. L.; Brazier, K.; Chiang, J.; Dingus, B. L.; Fichtel, C. E.; Fierro, J.; Hartman, R. C.; Hunter, S. D.; Kanbach, G.

1994-01-01

We report upper limits to the high-energy gamma-ray emission from the millisecond pulsars (MSPs) in a number of globular clusters. The observations were done as part of an all-sky survey by the energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO) during Phase I of the CGRO mission (1991 June to 1992 November). Several theoretical models suggest that MSPs may be sources of high-energy gamma radiation emitted either as primary radiation from the pulsar magnetosphere or as secondary radiation generated by conversion into photons of a substantial part of the relativistic e(+/-) pair wind expected to flow from the pulsar. To date, no high-energy emission has been detected from an individual MSP. However, a large number of MSPs are expected in globular cluster cores where the formation rate of accreting binary systems is high. Model predictions of the total number of pulsars range in the hundreds for some clusters. These expectations have been reinforced by recent discoveries of a substantial number of radio MSPs in several clusters; for example, 11 have been found in 47 Tucanae (Manchester et al.). The EGRET observations have been used to obtain upper limits for the efficiency eta of conversion of MSP spin-down power into hard gamma rays. The upper limits are also compared with the gamma-ray fluxes predicted from theoretical models of pulsar wind emission (Tavani). The EGRET limits put significant constraints on either the emission models or the number of pulsars in the globular clusters.

Effects of Platinum Nanocolloid in Combination with Gamma Irradiation on Normal Human Esophageal Epithelial Cells.

PubMed

Li, Qiang; Tanaka, Yoshiharu; Saitoh, Yasukazu; Miwa, Nobuhiko

2016-05-01

Our previous study demonstrated that platinum nanocolloid (Pt-nc), combined with lower-dose gamma irradiation at 3, 5, and 7 Gy significantly decreased proliferation and accelerated apoptosis of the human esophageal squamous cell carcinoma-derived cell line KYSE-70. The aim of the present study was to determine, under the same conditions as our previous study where gamma rays combined with Pt-nc were carcinostatic to KYSE-70 cells, if we could induce a radioprotective or the radiation-sensitizing effect on the human normal esophageal epithelial cells (HEEpiC). HEEpiC were treated with various Pt-nc concentrations and then irradiated with various gamma-ray doses. The proliferative status of HEEpiC was evaluated using trypan blue dye-exclusion and WST-8 assays. The cellular and nucleic morphological features were determined using crystal violet and Hoechst 33342 stainings, respectively. The intracellular level of reactive oxygen species (ROS) in HEEpiC was evaluated with a nitro blue tetrazolium (NBT) assay. The apoptotic status was detected with caspase-3, Bax, and Bcl-2 by Western blotting. Either Pt-nc or gamma irradiation could inhibit the growth of HEEpiC; however, their combined use exerted a significant proliferation-inhibitory effect in a Pt-nc dose-dependent manner than gamma irradiation alone. Pt-nc resulted in radiation sensitization rather than radiation protection on HEEpiC in vitro similar to KYSE-70 cells, when Pt-nc was administrated alone or combined with gamma irradiation. Thus, Pt-nc has an inhibitory effect on cell proliferation, a facilitative effect on apoptosis, and a certain degree of toxicity against HEEpiC.

The Energetic Gamma-Ray Experiment Telescope (EGRET) Science Symposium

NASA Technical Reports Server (NTRS)

Fichtel, Carl E. (Editor); Hunter, Stanley D. (Editor); Sreekumar, Parameswaran (Editor); Stecker, Floyd W. (Editor)

1990-01-01

The principle purpose of this symposium is to provide the EGRET (Energetic Gamma-Ray Experiment Telescope) scientists with an opportunity to study and improve their understanding of high energy gamma ray astronomy. The Symposium began with the galactic diffusion radiation both because of its importance in studying galactic cosmic rays, galactic structure, and dynamic balance, and because an understanding of its characteristics is important in the study of galactic sources. The galactic objects to be reviewed included pulsars, bursts, solar flares, and other galactic sources of several types. The symposium papers then proceeded outward from the Milky Way to normal galaxies, active galaxies, and the extragalactic diffuse radiation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akkurt, Iskender; Guenoglu, Kadir

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 themore » results will be discussed.« less

Biological wound dressings sterilized with gamma radiation: Mexican clinical experience

NASA Astrophysics Data System (ADS)

Martínez-Pardo, M. E.; Ley-Chávez, E.; Reyes-Frías, M. L.; Rodríguez-Ferreyra, P.; Vázquez-Maya, L.; Salazar, M. A.

2007-11-01

Biological wound dressings sterilized with gamma radiation, such as amnion and pig skin, are a reality in Mexico. These tissues are currently processed in the tissue bank and sterilized in the Gamma Industrial Irradiation Plant; both facilities belong to the Instituto Nacional de Investigaciones Nucleares (ININ) (National Institute of Nuclear Research). With the strong support of the International Atomic Energy Agency, the bank was established at the ININ and the Mexican Ministry of Health issued its sanitary license on July 7, 1999. The Quality Management System of the bank was certified by ISO 9001:2000 on August 1, 2003; the scope of the system is "Research, Development and Processing of Biological Tissues Sterilized with Gamma Radiation". At present, more than 150 patients from 16 hospitals have been successfully treated with these tissues. This paper presents a brief description of the tissue processing, as well as the present Mexican clinical experience with children and adult patients who underwent medical treatment with radiosterilized amnion and pig skin, used as biological wound dressings on burns and ocular surface disorders.

Gamma radiation effects on seed germination, growth and pigment content, and ESR study of induced free radicals in maize (Zea mays).

PubMed

Marcu, Delia; Damian, Grigore; Cosma, Constantin; Cristea, Victoria

2013-09-01

The effects of gamma radiation are investigated by studying plant germination, growth and development, and biochemical characteristics of maize. Maize dry seeds are exposed to a gamma source at doses ranging from 0.1 to 1 kGy. Our results show that the germination potential, expressed through the final germination percentage and the germination index, as well as the physiological parameters of maize seedlings (root and shoot lengths) decreased by increasing the irradiation dose. Moreover, plants derived from seeds exposed at higher doses (≤0.5 kGy) did not survive more than 10 days. Biochemical differences based on photosynthetic pigment (chlorophyll a, chlorophyll b, carotenoids) content revealed an inversely proportional relationship to doses of exposure. Furthermore, the concentration of chlorophyll a was higher than chlorophyll b in both irradiated and non-irradiated seedlings. Electron spin resonance spectroscopy used to evaluate the amount of free radicals induced by gamma ray treatment demonstrates that the relative concentration of radiation-induced free radicals depends linearly on the absorbed doses.

A Remote-operated System to Map Radiation Dose in the Fukushima Daiichi Primary Containment Vessel

NASA Astrophysics Data System (ADS)

Nancekievill, M.; Jones, A. R.; Joyce, M. J.; Lennox, B.; Watson, S.; Katakura, J.; Okumura, K.; Kamada, S.; Katoh, M.; Nishimura, K.

2018-01-01

This paper describes the development of a submersible system based on a remote-operated vehicle coupled with radiation detectors to map the interior of the reactors at the Fukushima Daiichi nuclear power station. It has the aim oflocating fuel debris. The AVEXIS submersible vehicle used in this study has been designed as a low-cost, potentially disposable, inspection platform that is the smallest of its class and is capable of being deployed through a 150 mm diameter access pipe. To map the gamma-ray environment, a cerium bromide scintillator detector with a small form factor has been incorporated into the AVEXIS to identify radioactive isotopes via gamma-ray spectroscopy. This provides the combined system with the potential to map gamma-ray spectra and particle locations throughout submerged, contaminated facilities, such as Units 1, 2 and 3 of the Fukushima Daiichi nuclear power plant. The hypothesis of this research is to determine the sensitivity of the combined system in a submerged environment that replicates the combination of gamma radiation and water submersion but at lower dose rates.

Thermal resistance, tensile properties, and gamma radiation shielding performance of unsaturated polyester/nanoclay/PbO composites

NASA Astrophysics Data System (ADS)

Bagheri, Kobra; Razavi, Seyed Mohammad; Ahmadi, Seyed Javad; Kosari, Mohammadreza; Abolghasemi, Hossein

2018-05-01

Composites of unsaturated polyester containing 5 wt% nanoclay and different amounts of lead monoxide particles (0, 10, 20, and 30 wt%) were prepared. XRD patterns showed the exfoliation of nanoclay layers in the polymer. Morphological properties of the composites were studied using SEM micrographs. The prepared composites were investigated for their thermal resistance and mechanical properties using thermogravimetric analysis and tensile testing method, respectively. Addition of lead monoxide to the polymer worsened its thermal resistance and tensile properties, whereas the observed negative effects could be moderated by the clay nanoparticle. Gamma attenuation performance of the composites was evaluated by 192Ir, 137Cs, and 60Co gamma radiation sources. Linear attenuation coefficient and mass attenuation coefficient of the composites were found to be increased with the increase of PbO content. Shielding efficiency of the prepared composites was compared with some conventional shielding materials regarding their half value layer thickness. UP/nanoclay/PbO composites were found to be suitable materials for the low-energy gamma radiation shielding applications.

Radiation-induced desulfurization of Arabian crude oil and straight-run diesel

NASA Astrophysics Data System (ADS)

Basfar, A. A.; Mohamed, K. A.

2011-11-01

Radiation-induced desulfurization of four types of Arabian crude oils (heavy, medium, light and extra light) and straight-run diesel (SRD) was investigated over the range of 10-200 kGy. Results show that gamma radiation processing at absorbed doses up to 200 kGy without further treatment is not sufficient for desulfurization. However, the combination of gamma-irradiation with other physical/chemical processes (i.e. L/L extraction, adsorption and oxidation) may be capable of removing considerable levels of sulfur compounds in the investigated products. Currently, this approach of combined radiation/physical/chemical processes is under investigation. The findings of these attempts will be reported in the future.

Effects of gamma radiation on spermatogenesis and fertility of male Amblyomma americanum (Acari: Ixodidae)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oliver, J.H. Jr.; Stanley, M.A.

1987-04-01

Amblyomma americanum males were treated with 0.5, 1, 2, 3, 4, 8, and 16 krad of gamma radiation. Testes of ticks treated with 2, 3, 4, 8, and 16 krad were smaller than those of ticks irradiated at lower levels and controls. No recognizable alteration in timing of spermatogenesis was noted among the different radiation groups, but severe breakdown and depletion of germinal cells was noted at 4, 8, and 16 krad. Percent hatch of larvae from crosses of irradiated males and untreated females decreased with increasing radiation level. No hatch was observed from eggs of females mated to malesmore » treated at 2 krad or higher.« less

The origin of the diffuse background gamma radiation

NASA Technical Reports Server (NTRS)

Stecker, F. W.; Puget, J. L.

1974-01-01

Recent observations provided evidence for diffuse background gamma radiation extending to energies beyond 100 MeV, and evidence of isotropy and implied cosmological origin. Significant features in the spectrum of this background radiation were observed which provide evidence for its origin in nuclear processes in the early stages of big-bang cosmology, and connect these processes with the galaxy formation theory. A test of the theory is in future observations of the background radiation in the 100 MeK to 100 GeV energy range which are made with large orbiting spark-chamber satellite detectors. The theoretical interpretations of present data, their connection with baryon-symmetric cosmology and galaxy formation theory, and the need for future observations are discussed.

High and low energy gamma beam dump designs for the gamma beam delivery system at ELI-NP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yasin, Zafar, E-mail: zafar.yasin@eli-np.ro; Matei, Catalin; Ur, Calin A.

The Extreme Light Infrastructure - Nuclear Physics (ELI-NP) is under construction in Magurele, Bucharest, Romania. The facility will use two 10 PW lasers and a high intensity, narrow bandwidth gamma beam for stand-alone and combined laser-gamma experiments. The accurate estimation of particle doses and their restriction within the limits for both personel and general public is very important in the design phase of any nuclear facility. In the present work, Monte Carlo simulations are performed using FLUKA and MCNPX to design 19.4 and 4 MeV gamma beam dumps along with shielding of experimental areas. Dose rate contour plots from both FLUKAmore » and MCNPX along with numerical values of doses in experimental area E8 of the facility are performed. The calculated doses are within the permissible limits. Furthermore, a reasonable agreement between both codes enhances our confidence in using one or both of them for future calculations in beam dump designs, radiation shielding, radioactive inventory, and other calculations releated to radiation protection. Residual dose rates and residual activity calculations are also performed for high-energy beam dump and their effect is negligible in comparison to contributions from prompt radiation.« less

INTERIM REPORT--INDEPENDENT VERIFICATION SURVEY OF SECTION 3, SURVEY UNITS 1, 4 AND 5 EXCAVATED SURFACES, WHITTAKER CORPORATION, REYNOLDS INDUSTRIAL PARK, TRANSFER, PENNSYLVANIA DCN: 5002-SR-04-0"

DOE Office of Scientific and Technical Information (OSTI.GOV)

ADAMS, WADE C

At Pennsylvania Department of Environmental Protection's request, ORAU's IEAV program conducted verification surveys on the excavated surfaces of Section 3, SUs 1, 4, and 5 at the Whittaker site on March 13 and 14, 2013. The survey activities included visual inspections, gamma radiation surface scans, gamma activity measurements, and soil sampling activities. Verification activities also included the review and assessment of the licensee's project documentation and methodologies. Surface scans identified four areas of elevated direct gamma radiation distinguishable from background; one area within SUs 1 and 4 and two areas within SU5. One area within SU5 was remediated by removingmore » a golf ball size piece of slag while ORAU staff was onsite. With the exception of the golf ball size piece of slag within SU5, a review of the ESL Section 3 EXS data packages for SUs 1, 4, and 5 indicated that these locations of elevated gamma radiation were also identified by the ESL gamma scans and that ESL personnel performed additional investigations and soil sampling within these areas. The investigative results indicated that the areas met the release criteria.« less

Ultraviolet-visible and fluorescence spectroscopy can be used as a diagnostic tool for gamma irradiation detection in vivo.

PubMed

K-Abdelhalim, Mohamed Anwar; Moussa, Sherif A-Abdelmottaleb

2016-09-01

The spectroscopic properties can indicate important features about the nature and severity of the disease. However, no earlier studies have been used the spectroscopic properties as a diagnostic tool for radiation detection. This study was aimed to use ultraviolet-visible and fluorescence spectroscopy as a diagnostic tool for gamma irradiation detection in rats in vivo. Adult male rats were exposed to 25, 50, 75 and 100 Gray as single dose, using Cobalt-60 (Co-60) source with a dose rate of 0.883 centi Gray/sec (cGy/s). Ultraviolet and fluorescence spectroscopy of rat's blood serum were measured. After gamma irradiation of rats in vivo, the blood serum absorbance peaks for 25, 50, 75 and 100 Gray (Gy) decreased and shifted towards the ultra violet wavelength. A maximal change in fluorescence intensity of blood serum at 350 nm was obtained when exciting light at 194 nm after irradiation. The fluorescence intensity also decreased with the dose. The highest radiation gamma dose might be accompanied with the highest oxidative stress. This study suggests that at the above mentioned gamma radiation doses, the blood is highly fragmented; with low aggregation at 25 Gy and with high aggregation at 50-100 Gy.

Investigation of gamma radiation induced changes in local structure of borosilicate glass by TDPAC and EXAFS

NASA Astrophysics Data System (ADS)

Kumar, Ashwani; Nayak, C.; Rajput, P.; Mishra, R. K.; Bhattacharyya, D.; Kaushik, C. P.; Tomar, B. S.

2016-12-01

Gamma radiation induced changes in local structure around the probe atom (Hafnium) were investigated in sodium barium borosilicate (NBS) glass, used for immobilization of high level liquid waste generated from the reprocessing plant at Trombay, Mumbai. The (NBS) glass was doped with 181Hf as a probe for time differential perturbed angular correlation (TDPAC) spectroscopy studies, while for studies using extended X-ray absorption fine structure (EXAFS) spectroscopy, the same was doped with 0.5 and 2 % (mole %) hafnium oxide. The irradiated as well as un-irradiated glass samples were studied by TDPAC and EXAFS techniques to obtain information about the changes (if any) around the probe atom due to gamma irradiation. TDPAC spectra of unirradiated and irradiated glasses were similar and reminescent of amorphous materials, indicating negligible effect of gamma radiation on the microstructure around Hafnium probe atom, though the quaqdrupole interaction frequency ( ω Q) and asymmetry parameter ( η) did show a marginal decrease in the irradiated glass compared to that in the unirradiated glass. EXAFS measurements showed a slight decrease in the Hf-O bond distance upon gamma irradiation of Hf doped NBS glass indicating densification of the glass matrix, while the cordination number around hafnium remains unchanged.

Titanium-Water Thermosyphon Gamma Radiation Exposure and Results

NASA Technical Reports Server (NTRS)

Sanzi, James, L.A; Jaworske, Donald, A.; Goodenow, Debra, A.

2012-01-01

Titanium-water thermosyphons are being considered for use in heat rejection systems for fission power systems. Their proximity to the nuclear reactor will result in some gamma irradiation. Noncondensable gas formation from radiation-induced breakdown of water over time may render portions of the thermosyphon condenser inoperable. A series of developmental thermosyphons were operated at nominal operating temperature under accelerated gamma irradiation, with exposures on the same order of magnitude as that expected in 8 years of heat rejection system operation. Temperature data were obtained during exposure at three locations on each thermosyphon: evaporator, condenser, and condenser end cap. Some noncondensable gas was evident; however, thermosyphon performance was not affected because the noncondensable gas was compressed into the fill tube region at the top of the thermosyphon, away from the heat rejecting fin. The trend appeared to be an increasing amount of noncondensable gas formation with increasing gamma irradiation dose. Hydrogen is thought to be the most likely candidate for the noncondensable gas and hydrogen is known to diffuse through grain boundaries. Post-exposure evaluation of one thermosyphon in a vacuum chamber and at temperature revealed that the noncondensable gas diffused out of the thermosyphon over a relatively short period of time. Further research shows a number of experimental and theoretical examples of radiolysis occurring through gamma radiation alone in pure water.

NASA Cold Land Processes Experiment (CLPX 2002/03): Airborne remote sensing

Treesearch

Don Cline; Simon Yueh; Bruce Chapman; Boba Stankov; Al Gasiewski; Dallas Masters; Kelly Elder; Richard Kelly; Thomas H. Painter; Steve Miller; Steve Katzberg; Larry Mahrt

2009-01-01

This paper describes the airborne data collected during the 2002 and 2003 Cold Land Processes Experiment (CLPX). These data include gamma radiation observations, multi- and hyperspectral optical imaging, optical altimetry, and passive and active microwave observations of the test areas. The gamma observations were collected with the NOAA/National Weather Service Gamma...

Effects of low-dose gamma-irradiation on production of shikonin derivatives in callus cultures of Lithospermum erythrorhizon S.

NASA Astrophysics Data System (ADS)

Chung, B. Y.; Lee, Y.-B.; Baek, M.-H.; Kim, J.-H.; Wi, S. G.; Kim, J.-S.

2006-09-01

The yield increase of secondary metabolite production was examined in plant cell cultures with the use of relatively low to high doses gamma irradiation. Suspension culture of Lithospermum erythrorhizon cells was irradiated to 2, 16, and 32 Gy. The gamma irradiation significantly stimulated the shikonin biosynthesis of the cells and increased the total shikonin yields (intracellular+extracellular shikonin yields) by 400% at 16 Gy and by only 240% and 180% at 2 and 32 Gy, respectively. One of the key enzymes for the shikonin biosynthesis of cells, p-hydroxylbenzoic acid (PHB) geranyltransferase, was found to be stimulated by the gamma-radiation treatments. The activity of PHB geranyltransferase was increased at 2 and 16 Gy with a negligible change at 32 Gy. In contrast, the activity of PHB glucosyltransferase was slightly changed at all doses of gamma radiation compared with the control cells. Therefore, the increase in PHB geranyltransferase activity leads to the accumulation of secondary metabolites such as a shikonin, which may contribute to plant defense against the stresses induced by gamma irradiation.

Quality assurance for gamma knives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, E.D.; Banks, W.W.; Fischer, L.E.

1995-09-01

This report describes and summarizes the results of a quality assurance (QA) study of the Gamma Knife, a nuclear medical device used for the gamma irradiation of intracranial lesions. Focus was on the physical aspects of QA and did not address issues that are essentially medical, such as patient selection or prescription of dose. A risk-based QA assessment approach was used. Sample programs for quality control and assurance are included. The use of the Gamma Knife was found to conform to existing standards and guidelines concerning radiation safety and quality control of external beam therapies (shielding, safety reviews, radiation surveys,more » interlock systems, exposure monitoring, good medical physics practices, etc.) and to be compliant with NRC teletherapy regulations. There are, however, current practices for the Gamma Knife not covered by existing, formalized regulations, standards, or guidelines. These practices have been adopted by Gamma Knife users and continue to be developed with further experience. Some of these have appeared in publications or presentations and are slowly finding their way into recommendations of professional organizations.« less

Celestial diffuse gamma radiation above 30 MeV observed by SAS-2

NASA Technical Reports Server (NTRS)

Fichtel, C. E.; Kniffen, D. A.; Hartman, R. C.

1973-01-01

The Small Astronomy Satellite (SAS)-2, launched on November 15, 1972, carried into orbit a 32-deck magnetic-core digitized spark chamber gamma ray telescope to study celestial gamma radiation in the energy range above 30 MeV. In the study of several regions with b sub 2 15 deg, a finite, diffuse flux of gamma rays with a steep energy spectrum in the energy region from 35 to 200 MeV is observed. Representing the energy spectrum by a power law of the form dJ/dE = AE to - alpha power over this energy range, alpha is found along with the integral flux above 100 MeV. Combining this result with existing low energy gamma ray data yields an energy spectrum which is not a simple power law in energy, as in the X-ray region, but which demonstrates first an increase and then a decrease in slope, consistent within uncertainties with that predicted by cosmological theories, including the continuous production of high energy gamma rays primarily from neutral pi mesons throughout the history of the universe.

Effect of low-dose (1 kGy) gamma radiation and selected phosphates on the microflora of vacuum-packaged ground pork

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ehioba, R.M.

1987-01-01

The effects of low-dose (1 kGy) gamma radiation and selected phosphates on the microbiology of refrigerated, vacuum-packaged ground pork were studied. Low-dose gamma radiation reduced the numbers of naturally occurring mesophiles, psychrotrophs, and anaerobes. The effect of low-dose radiation on the populations of lactic acid bacteria was minimal. On storage of the irradiated vacuum-packaged ground pork at 5/sup 0/C, there was a partial bacterial recovery, suggesting sublethal bacterial injury due to irradiation. When 10/sup 7/ CFU/g of meat is taken to be the level beyond which the meat would be considered spoiled, uninoculated, vacuum-packaged ground pork treated with 1 kGymore » (100 krad) of gamma radiation had 3.5 more days of shelf-life in terms of psychrotrophic total counts. In relation to anaerobic bacterial numbers, meat shelf-life was extended 2.5 days, while the shelf-life of meat was extended 1 day in terms of aerobic mesophilic bacteria. Irradiation prolonged shelf-life in inoculated (10/sup 5/CFU/g) meat for 1.0-1.5 days. Addition of 0.4% sodium acid pyrophosphate (SAPP) contributed 2 additional days to inoculated, irradiated vacuum-packaged ground pork shelf-life. However, SAPP had no added effect on naturally occurring microflora. Irradiation greatly decreased the numbers of gram-negative microorganisms, resulting in predominance of the gram-positive, nonsporeforming Lactobacillus and coryneform bacteria.« less

Neutron radiative capture methods for surface elemental analysis

USGS Publications Warehouse

Trombka, J.I.; Senftle, F.; Schmadebeck, R.

1970-01-01

Both an accelerator and a 252Cf neutron source have been used to induce characteristic gamma radiation from extended soil samples. To demonstrate the method, measurements of the neutron-induced radiative capture and activation gamma rays have been made with both Ge(Li) and NaI(Tl) detectors, Because of the possible application to space flight geochemical analysis, it is believed that NaI(Tl) detectors must be used. Analytical procedures have been developed to obtain both qualitative and semiquantitative results from an interpretation of the measured NaI(Tl) pulse-height spectrum. Experiment results and the analytic procedure are presented. ?? 1970.

Degradation of Biochemical Activity in Soil Sterilized by Dry Heat and Gamma Radiation

NASA Technical Reports Server (NTRS)

Shih, K. L.; Souza, K. A.

1978-01-01

The effect of soil sterilization by dry heat (0.08% relative humidity), gamma radiation, or both on soil phosphatase, urease, and decarboxylase activity was studied. Soil sterilized by a long exposure to dry heat at relatively low temperatures (eight weeks at 100.5 C) retained higher activities than did soil exposed to a higher temperature (two weeks at 124.5 C), while all activity was destroyed by four days at 148.5 C. Sterilization with 7.5 Mrads destroyed less activity than did heat sterilization. The effect of several individually nonsterizing doses of heat radiation is described.

Calibration of the active radiation detector for Spacelab-One

NASA Technical Reports Server (NTRS)

1982-01-01

The flight models of the active radiation detector (ARD) for the ENV-01 environmental monitor were calibrated using gamma radiation. Measured sensitivities of the ion chambers were 6.1 + or - 0.3 micron rad per count for ARD S/N1, and 10.4 + or - 0.5 micron rad per count for ARD S/N2. Both were linear over the measured range 0.10 to 500 m/rad hour. The particle counters (proportional counters) were set to respond to approximately 85% of minimum ionizing particles of unit charge passing through them. These counters were also calibrated in the gamma field.

Validation of γ-radiation and ultraviolet as a new inactivators for foot and mouth disease virus in comparison with the traditional methods

PubMed Central

Mahdy, Safy El din; Hassanin, Amr Ismail; Gamal El-Din, Wael Mossad; Ibrahim, Ehab El-Sayed; Fakhry, Hiam Mohamed

2015-01-01

Aim: The present work deals with different methods for foot and mouth disease virus (FMDV) inactivation for serotypes O/pan Asia, A/Iran05, and SAT-2/2012 by heat, gamma radiation, and ultraviolet (UV) in comparison with the traditional methods and their effects on the antigenicity of viruses for production of inactivated vaccines. Materials and Methods: FMDV types O/pan Asia, A/Iran05, and SAT-2/2012 were propagated in baby hamster kidney 21 (BHK21) and titrated then divided into five parts; the first part inactivated with heat, the second part inactivated with gamma radiation, the third part inactivated with UV light, the fourth part inactivated with binary ethylamine, and the last part inactivated with combination of binary ethylamine and formaldehyde (BEI+FA). Evaluate the method of inactivation via inoculation in BHK21, inoculation in suckling baby mice and complement fixation test then formulate vaccine using different methods of inactivation then applying the quality control tests to evaluate each formulated vaccine. Results: The effect of heat, gamma radiation, and UV on the ability of replication of FMDV “O/pan Asia, A/Iran05, and SAT-2/2012” was determined through BHK cell line passage. Each of the 9 virus aliquots titer 108 TCID50 (3 for each strain) were exposed to 37, 57, and 77°C for 15, 30, and 45 min. Similarly, another 15 aliquots (5 for each strain) contain 1 mm depth of the exposed samples in petri-dish was exposed to UV light (252.7 nm wavelength: One foot distance) for 15, 30, 45, 60, and 65 min. Different doses of gamma radiation (10, 20, 25, 30, 35, 40, 45, 50, 55, and 60 KGy) were applied in a dose rate 0.551 Gy/s for each strain and repeated 6 times for each dose. FMDV (O/pan Asia, A/Iran05, and SAT-2/2012) were inactivated when exposed to heat ≥57°C for 15 min. The UV inactivation of FMDV (O/pan Asia and SAT-2) was obtained within 60 min and 65 min for type A/Iran05. The ideal dose for inactivation of FMDV (O/pan Asia, A/Iran05, and SAT-2/2012) with gamma radiation were 55-60 and 45 kGy, respectively. Inactivation of FMDV with binary was 20, 24 and 16 hr for O/pan Asia, A/Iran05, and SAT-2/2012, respectively while inactivation by (BEI+FA) was determined after 18, 19 and 11 hr for O/pan-Asia, A/Iran 05, and SAT-2/2012, respectively. The antigenicity of control virus before inactivation was 1/32, it was not changed after inactivation in case of gamma radiation and (BEI+FA) and slightly decrease to 1/16 in case of binary and declined to 1/2, 1/4 in case of heat and UV inactivation, respectively. The immune response induced by inactivated FMD vaccines by gamma radiation and (BEI+FA) lasted to 9 months post-vaccination, while the binary only still up to 8 months post-vaccination but heat and UV-inactivated vaccines were not effective. Conclusion: Gamma radiation could be considered a good new inactivator inducing the same results of inactivated vaccine by binary with formaldehyde (BEI+FA). PMID:27047204

High dietary iron increases oxidative stress and radiosensitivity in the rat retina and vasculature after exposure to fractionated gamma radiation

PubMed Central

Theriot, Corey A; Westby, Christian M; Morgan, Jennifer L L; Zwart, Sara R; Zanello, Susana B

2016-01-01

Radiation exposure in combination with other space environmental factors including microgravity, nutritional status, and deconditioning is a concern for long-duration space exploration missions. Astronauts experience altered iron homeostasis due to adaptations to microgravity and an iron-rich food system. Iron intake reaches three to six times the recommended daily allowance due to the use of fortified foods on the International Space Station. Iron is associated with certain optic neuropathies and can potentiate oxidative stress. This study examined the response of eye and vascular tissue to gamma radiation exposure (3 Gy fractionated at 37.5 cGy per day every other day for 8 fractions) in rats fed an adequate-iron diet or a high-iron diet. Twelve-week-old Sprague-Dawley rats were assigned to one of four experimental groups: adequate-iron diet/no radiation (CON), high-iron diet/no radiation (IRON), adequate-iron diet/radiation (RAD), and high-iron diet/radiation (IRON+RAD). Animals were maintained on the corresponding iron diet for 2 weeks before radiation exposure. As previously published, the high-iron diet resulted in elevated blood and liver iron levels. Dietary iron overload altered the radiation response observed in serum analytes, as evidenced by a significant increase in catalase levels and smaller decrease in glutathione peroxidase and total antioxidant capacity levels. 8-OHdG immunostaining, showed increased intensity in the retina after radiation exposure. Gene expression profiles of retinal and aortic vascular samples suggested an interaction between the response to radiation and high dietary iron. This study suggests that the combination of gamma radiation and high dietary iron has deleterious effects on retinal and vascular health and physiology. PMID:28725729

A new measurement of the rare decay eta -> pi^0 gamma gamma with the Crystal Ball/TAPS detectors at the Mainz Microtron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nefkens, B M; Prakhov, S; Aguar-Bartolom��, P

2014-08-01

A new measurement of the rare, doubly radiative decay eta->pi^0 gamma gamma was conducted with the Crystal Ball and TAPS multiphoton spectrometers together with the photon tagging facility at the Mainz Microtron MAMI. New data on the dependence of the partial decay width, Gamma(eta->pi^0 gamma gamma), on the two-photon invariant mass squared, m^2(gamma gamma), as well as a new, more precise value for the decay width, Gamma(eta->pi^0 gamma gamma) = (0.33+/-0.03_tot) eV, are based on analysis of 1.2 x 10^3 eta->pi^0 gamma gamma decays from a total of 6 x 10^7 eta mesons produced in the gamma p -> etamore » p reaction. The present results for dGamma(eta->pi^0 gamma gamma)/dm^2(gamma gamma) are in good agreement with previous measurements and recent theoretical calculations for this dependence.« less

Clinical outcomes of gamma knife radiosurgery in the salvage treatment of patients with recurrent high-grade glioma.

PubMed

Elaimy, Ameer L; Mackay, Alexander R; Lamoreaux, Wayne T; Demakas, John J; Fairbanks, Robert K; Cooke, Barton S; Lamm, Andrew F; Lee, Christopher M

2013-12-01

Previously published randomized evidence did not report a survival advantage for patients diagnosed with grade IV glioma who were treated with stereotactic radiosurgery followed by external beam radiation therapy and chemotherapy when compared to patients treated with external beam radiation therapy and chemotherapy alone. In recent years, gamma knife radiosurgery has become increasingly popular as a salvage treatment modality for patients diagnosed with recurrent high-grade glioma. The purpose of this article is to review the efficacy of gamma knife radiosurgery for patients who suffer from this malignancy. Retrospective, prospective, and randomized clinical studies published between the years 2000 and 2012 analyzing gamma knife radiosurgery for patients with high-grade glioma were reviewed. After assessing patient age, Karnofsky performance status, tumor histology, and extent of resection, gamma knife radiosurgery is a viable, minimally invasive treatment option for patients diagnosed with recurrent high-grade glioma. The available prospective and retrospective evidence suggests that gamma knife radiosurgery provides patients with a high local tumor control rate and a median survival after tumor recurrence ranging from 13 to 26 months. Gamma knife radiosurgery followed by chemotherapy for recurrent high-grade glioma may provide select patients with increased levels of survival. However, further investigation into this matter is needed due to the limited number of published reports. Additional clinical research is also needed to analyze the efficacy and radiation-related toxicities of fractionated gamma knife radiosurgery due to its potential to limit treatment-associated morbidity. Gamma knife radiosurgery is a safe and effective treatment option for select patients diagnosed with recurrent high-grade glioma. Although treatment outcomes have improved, further evidence in the form of phase III randomized trials is needed to assess the durability of treating patients in specific clinical situations. Copyright © 2013 Elsevier Inc. All rights reserved.

Radioprotective Effects of Gallic Acid in Mice

PubMed Central

Nair, Gopakumar Gopinathan

2013-01-01

Radioprotecting ability of the natural polyphenol, gallic acid (3,4,5-trihydroxybenzoic acid, GA), was investigated in Swiss albino mice. Oral administration of GA (100 mg/kg body weight), one hour prior to whole body gamma radiation exposure (2–8 Gy; 6 animals/group), reduced the radiation-induced cellular DNA damage in mouse peripheral blood leukocytes, bone marrow cells, and spleenocytes as revealed by comet assay. The GA administration also prevented the radiation-induced decrease in the levels of the antioxidant enzyme, glutathione peroxidise (GPx), and nonprotein thiol glutathione (GSH) and inhibited the peroxidation of membrane lipids in these animals. Exposure of mice to whole body gamma radiation also caused the formation of micronuclei in blood reticulocytes and chromosomal aberrations in bone marrow cells, and the administration of GA resulted in the inhibition of micronucleus formation and chromosomal aberrations. In irradiated animals, administration of GA elicited an enhancement in the rate of DNA repair process and a significant increase in endogenous spleen colony formation. The administration of GA also prevented the radiation-induced weight loss and mortality in animals (10 animals/group) exposed to lethal dose (10 Gy) of gamma radiation. (For every experiment unirradiated animals without GA administration were taken as normal control; specific dose (Gy) irradiated animals without GA administration serve as radiation control; and unirradiated GA treated animals were taken as drug alone control). PMID:24069607

Effects of /spl gamma/-rays on JFET devices and circuits fabricated in a detector-compatible Process

NASA Astrophysics Data System (ADS)

Betta, G. F. D.; Manghisoni, M.; Ratti, L.; Re, V.; Speziali, V.; Traversi, G.

2003-12-01

This work is concerned with the effects of /spl gamma/-rays on the static, signal and noise characteristics of JFET-based circuits belonging to a fabrication technology made available by the Istituto per la Ricerca Scientifica e Tecnologica (ITC-IRST), Trento, Italy. Such a process has been tuned with the aim of monolithically integrating the readout electronics on the same highly resistive substrate as multielectrode silicon detectors. The radiation tolerance of some test structures, including single devices and charge sensitive amplifiers, was studied in view of low-noise applications in industrial and medical imaging, X- and /spl gamma/-ray astronomy and high energy physics experiments. This paper intends to fill the gap in the study of gamma radiation effects on JFET devices and circuits belonging to detector-compatible technologies.

A population of gamma-ray millisecond pulsars seen with the Fermi Large Area Telescope.

PubMed

Abdo, A A; Ackermann, M; Ajello, M; Atwood, W B; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Baring, M G; Bastieri, D; Baughman, B M; Bechtol, K; Bellazzini, R; Berenji, B; Bignami, G F; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Burnett, T H; Caliandro, G A; Cameron, R A; Camilo, F; Caraveo, P A; Carlson, P; Casandjian, J M; Cecchi, C; Celik, O; Charles, E; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cognard, I; Cohen-Tanugi, J; Cominsky, L R; Conrad, J; Corbet, R; Cutini, S; Dermer, C D; Desvignes, G; de Angelis, A; de Luca, A; de Palma, F; Digel, S W; Dormody, M; do Couto e Silva, E; Drell, P S; Dubois, R; Dumora, D; Edmonds, Y; Farnier, C; Favuzzi, C; Fegan, S J; Focke, W B; Frailis, M; Freire, P C C; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giebels, B; Giglietto, N; Giordano, F; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M H; Grove, J E; Guillemot, L; Guiriec, S; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Hobbs, G; Hughes, R E; Jóhannesson, G; Johnson, A S; Johnson, R P; Johnson, T J; Johnson, W N; Johnston, S; Kamae, T; Katagiri, H; Kataoka, J; Kawai, N; Kerr, M; Knödlseder, J; Kocian, M L; Kramer, M; Kuss, M; Lande, J; Latronico, L; Lemoine-Goumard, M; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Makeev, A; Manchester, R N; Marelli, M; Mazziotta, M N; McConville, W; McEnery, J E; McLaughlin, M A; Meurer, C; Michelson, P F; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nolan, P L; Norris, J P; Nuss, E; Ohsugi, T; Omodei, N; Orlando, E; Ormes, J F; Paneque, D; Panetta, J H; Parent, D; Pelassa, V; Pepe, M; Pesce-Rollins, M; Piron, F; Porter, T A; Rainò, S; Rando, R; Ransom, S M; Ray, P S; Razzano, M; Rea, N; Reimer, A; Reimer, O; Reposeur, T; Ritz, S; Rochester, L S; Rodriguez, A Y; Romani, R W; Roth, M; Ryde, F; Sadrozinski, H F W; Sanchez, D; Sander, A; Saz Parkinson, P M; Scargle, J D; Schalk, T L; Sgrò, C; Siskind, E J; Smith, D A; Smith, P D; Spandre, G; Spinelli, P; Stappers, B W; Starck, J L; Striani, E; Strickman, M S; Suson, D J; Tajima, H; Takahashi, H; Tanaka, T; Thayer, J B; Thayer, J G; Theureau, G; Thompson, D J; Thorsett, S E; Tibaldo, L; Torres, D F; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, T L; Van Etten, A; Vasileiou, V; Venter, C; Vilchez, N; Vitale, V; Waite, A P; Wallace, E; Wang, P; Watters, K; Webb, N; Weltevrede, P; Winer, B L; Wood, K S; Ylinen, T; Ziegler, M

2009-08-14

Pulsars are born with subsecond spin periods and slow by electromagnetic braking for several tens of millions of years, when detectable radiation ceases. A second life can occur for neutron stars in binary systems. They can acquire mass and angular momentum from their companions, to be spun up to millisecond periods and begin radiating again. We searched Fermi Large Area Telescope data for pulsations from all known millisecond pulsars (MSPs) outside of globular clusters, using rotation parameters from radio telescopes. Strong gamma-ray pulsations were detected for eight MSPs. The gamma-ray pulse profiles and spectral properties resemble those of young gamma-ray pulsars. The basic emission mechanism seems to be the same for MSPs and young pulsars, with the emission originating in regions far from the neutron star surface.

Intense Gamma-Ray Flashes Above Thunderstorms on the Earth and Other Planets

NASA Technical Reports Server (NTRS)

Fishman, Gerald J.

2010-01-01

Intense millisecond flashes of MeV photons have been observed with space-borne detectors in Earth orbit. They are expected to be present on other planets that exhibit lightning. The terrestrial gamma-ray flashes (TGFs) were discovered with the Burst and Transient Source Experiment (BATSE) aboard the Compton Gamma-Ray Observatory (CGRO) in the early 1990s. They are now being observed with several other instruments, including the Gamma-ray Burst Monitor (GBM) detectors on the Fermi Gamma-ray Space Telescope. Although Fermi- GBM was designed and optimized for the observation of cosmic gamma-ray bursts (GRBs), it has unprecedented capabilities for TGF observations. The TGFs usually have extremely hard continuous spectra, typical of highly- Comptonized bremsstrahlung radiation. These spectral are harder than those of GRBs, with photons extending to over 40 MeV. The most likely origin of these high-energy photons is bremsstrahlung radiation produced by a relativistic "runaway avalanche" electron beam. Such a beam is expected to be produced in an extended, intense electric field in or above thunderstorm regions. The altitude of origin and beaming characteristics of the radiation are quite uncertain. They have generated considerable observational and theoretical interest in recent years. This talk will give an overview of the all of the space-borne observations of TGFs that have been made thus far. Instruments are being designed specifically for TGF observations from new spacecraft as well as from airborne platforms

SAS-2 observations of the diffuse gamma radiation in the galactic latitude interval from 10 to 90 deg in both hemispheres

NASA Technical Reports Server (NTRS)

Fichtel, C. E.; Hartman, R. C.; Kniffen, D. A.; Thompson, D. J.; Ogelman, H. B.; Ozel, M. E.; Tumer, T.

1977-01-01

An analysis of all the second Small Astronomy Satellite (SAS-2) gamma-ray data for galactic latitudes higher than 10 deg in both hemispheres has shown that the intensity varies with galactic latitude, being larger near 10 deg than 90 deg. For energies above 100 MeV the gamma-ray data are consistent with a latitude distribution of the form I(b) = C1 + C2/sin b, with the second term being dominant. This result suggests that the radiation above 100 MeV is coming largely from local regions of the galactic disk. Between 35 and 100 MeV, a similar equation is also a good representation of the data, but here the two terms are comparable. These results indicate that the diffuse radiation above 35 MeV consists of two parts, one with a relatively hard galactic component and the other an isotropic steep spectral component which extrapolates back well to the low-energy (less than 10 MeV) diffuse radiation. The steepness of the diffuse isotropic component places significant constraints on possible theoretical models of this radiation.

Results of calculations of external gamma radiation exposure rates from local fallout and the related radionuclide compositions of two hypothetical 1-MT nuclear bursts. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hicks, H.

1984-12-01

This report presents data on calculated gamma radiation exposure rates and local surface deposition of related radionuclides resulting from two hypothetical 1-Mt nuclear bursts. Calculations are made of the debris from two types of bombs: one containing /sup 235/U as a fissionable material (designated oralloy), the other containing /sup 238/U (designated tuballoy). 4 references.

Comparison of the NIST and ENEA Air Kerma Standards

PubMed Central

Laitano, R. F.; Lamperti, P. J.; Toni, M. P.

1998-01-01

A comparison was made between the National Institute of Standards and Technology (NIST) and Ente per le Nuove Tecnologie l’Energia e l’Ambiente (ENEA) air kerma standards for medium energy x rays and 60Co gamma rays. The comparison took place at ENEA in June 1994. Two different transfer chambers from NIST were used for the comparison. The measurements were made at radiation qualities similar to those used at the Bureau International des Poids et Mesures (BIPM) (generating voltages of 100 kV, 135 kV, 180 kV and 250 kV, respectively) and with 60Co gamma radiation. The transfer chamber calibration factors obtained at the NIST and at the ENEA agreed with one another to 0.03 % for 60Co gamma radiation and between 0.1 % to 0.8 % for the medium energy x-ray beam codes. PMID:28009356

Comparison of the NIST and ENEA air kerma standards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laitano, R.F.; Toni, M.P.; Lamperti, P.J.

1998-07-01

A comparison was made between the National Institute of Standards and Technology (NIST) and Ente per le Nuov Tecnologie l`Energia e l`Ambiente (ENEA) air kerma standards for medium energy x rays and {sup 60}Co gamma rays. The comparison took place at ENEA in June 1994. Two different transfer chambers from NIST were used for the comparison. The measurements were made at radiation qualities similar to those used at the Bureau International des Poids et Mesures (BIPM) (generating voltages of 100 kV, 135 kV, 180 kV and 250 kV, respectively) and with {sup 60}Co gamma radiation. The transfer chamber calibration factorsmore » obtained at the NIST and at the ENEA agreed with one another to 0.03% for {sup 60}Co gamma radiation and between 0.1% to 0.8% for the medium energy x-ray beam codes.« less

TeV gamma rays from 3C 279 - A possible probe of origin and intergalactic infrared radiation fields

NASA Technical Reports Server (NTRS)

Stecker, F. W.; De Jager, O. C.; Salamon, M. H.

1992-01-01

The gamma-ray spectrum of 3C 279 during 1991 June exhibited a near-perfect power law between 50 MeV and over 5 GeV with a differential spectral index of -(2.02 +/- 0.07). If extrapolated, the gamma-ray spectrum of 3C 279 should be easily detectable with first-generation air Cerenkov detectors operating above about 0.3 TeV provided there is no intergalactic absorption. However, by using model-dependent lower and upper limits for the extragalactic infrared background radiation field, a sharp cutoff of the 3C 279 spectrum is predicted at between about 0.1 and about 1 TeV. The sensitivity of present air Cerenkov detectors is good enough to measure such a cutoff, which would provide the first opportunity to obtain a measurement of the extragalactic background infrared radiation field.

Effect of Panax ginseng saponins and Eleutherococcus senticosus on survival of cultured mammalian cells after ionizing radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ben-Hur, E.; Fulder, S.

Panax ginseng saponin and Eleutherococcus senticosus extract were applied to cells in culture in order to assess the effect of these substances on resistance to gamma-irradiation. Eleutherococcus was slightly radio protective. However, ginseng saponin at a dose of 10 microgram/ml was significantly radioprotective (Do . 2.25 Gy) compared to control (Do . 1.80 Gy) when it was present prior to gamma-irradiation. It enhanced radiation response if it was also present for 4-6 hours after gamma-irradiation (Do . 1.10 Gy). Ginseng-treated cells made 30% less RNA and 14% more protein during a 1 hour pulse of labeled intermediates. The cells weremore » morphologically altered. It is concluded that ginseng saponin can increase radiation resistance. The effect is indirect, due to alterations in cell physiology rather than DNA repair processes.« less

An airport cargo inspection system based on X-ray and thermal neutron analysis (TNA).

PubMed

Ipe, Nisy E; Akery, A; Ryge, P; Brown, D; Liu, F; Thieu, J; James, B

2005-01-01

A cargo inspection system incorporating a high-resolution X-ray imaging system with a material-specific detection system based on Ancore Corporation's patented thermal neutron analysis (TNA) technology can detect bulk quantities of explosives and drugs concealed in trucks or cargo containers. The TNA process utilises a 252Cf neutron source surrounded by a moderator. The neutron interactions with the inspected object result in strong and unique gamma-ray signals from nitrogen, which is a key ingredient in modern high explosives, and from chlorinated drugs. The TNA computer analyses the gamma-ray signals and automatically determines the presence of explosives or drugs. The radiation source terms and shielding design of the facility are described. For the X-ray generator, the primary beam, leakage radiation, and scattered primary and leakage radiation were considered. For the TNA, the primary neutrons and tunnel scattered neutrons as well as the neutron-capture gamma rays were considered.

Time encoded radiation imaging

DOEpatents

Marleau, Peter; Brubaker, Erik; Kiff, Scott

2014-10-21

The various technologies presented herein relate to detecting nuclear material at a large stand-off distance. An imaging system is presented which can detect nuclear material by utilizing time encoded imaging relating to maximum and minimum radiation particle counts rates. The imaging system is integrated with a data acquisition system that can utilize variations in photon pulse shape to discriminate between neutron and gamma-ray interactions. Modulation in the detected neutron count rates as a function of the angular orientation of the detector due to attenuation of neighboring detectors is utilized to reconstruct the neutron source distribution over 360 degrees around the imaging system. Neutrons (e.g., fast neutrons) and/or gamma-rays are incident upon scintillation material in the imager, the photons generated by the scintillation material are converted to electrical energy from which the respective neutrons/gamma rays can be determined and, accordingly, a direction to, and the location of, a radiation source identified.

Evaluation of The Combined Effects of Hyperthermia, Cobalt-60 Gamma Rays and IUdR on Cultured Glioblastoma Spheroid Cells and Dosimetry Using TLD-100

PubMed Central

Neshasteh-Riz, Ali; Rahdani, Rozhin; Mostaar, Ahmad

2014-01-01

Objective In radiation treatment, the irradiation which is effective enough to control the tumors far exceeds normal-tissues tolerance. Thus to avoid such unfavourable outcomes, some methods sensitizing the tumor cells to radiation are used. Iododeoxyuridine (IUdR) is a halogenated thymidine analogue that known to be effective as a radiosensitizer in human cancer therapy. Improving the potential efficacy of radiation therapy after combining to hyperthermia depends on the magnitude of the differential sensitization of the hyperthermic effects or on the differential cytotoxicity of the radiation effects on the tumor cells. In this study, we evaluated the combined effects of IUdR, hyperthermia and gamma rays of 60Co on human glioblastoma spheroids culture. Materials and Methods In this experimental study,the cultured spheroids with 100µm diameter were treated by 1 µM IUdR, 43°C hyperthermia for an hour and 2 Gy gamma rays, respectively. The DNA damages induced in cells were compared using alkaline comet assay method, and dosimetry was then performed by TLD-100. Comet scores were calculated as mean ± standard error of mean (SEM) using one-way ANOVA. Results Comparison of DNA damages induced by IUdR and hyperthermia + gamma treatment showed 2.67- and 1.92-fold enhancement, respectively, as compared to the damages induced by radiation alone or radiation combined IUdR. Dosimetry results showed the accurate dose delivered to cells. Conclusion Analysis of the comet tail moments of spheroids showed that the radiation treatments combined with hyperthermia and IUdR caused significant radiosensitization when compared to related results of irradiation alone or of irradiation with IUdR. These results suggest a potential clinical advantage of combining radiation with hyperthermia and indicate effectiveness of hyperthermia treatment in inducing cytotoxicity of tumor cells. PMID:24611138

Gamma dosimetric parameters in some skeletal muscle relaxants

NASA Astrophysics Data System (ADS)

Manjunatha, H. C.

2017-09-01

We have studied the attenuation of gamma radiation of energy ranging from 84 keV to 1330 keV (^{170}Tm, ^{22}Na,^{137}Cs, and ^{60}Co) in some commonly used skeletal muscle relaxants such as tubocurarine chloride, gallamine triethiodide, pancuronium bromide, suxamethonium bromide and mephenesin. The mass attenuation coefficient is measured from the attenuation experiment. In the present work, we have also proposed the direct relation between mass attenuation coefficient (μ /ρ ) and mass energy absorption coefficient (μ _{en}/ρ ) based on the nonlinear fitting procedure. The gamma dosimetric parameters such as mass energy absorption coefficient (μ _{en}/ρ ), effective atomic number (Z_{eff}), effective electron density (N_{el}), specific γ-ray constant, air kerma strength and dose rate are evaluated from the measured mass attentuation coefficient. These measured gamma dosimetric parameters are compared with the theoretical values. The measured values agree with the theoretical values. The studied gamma dosimetric values for the relaxants are useful in medical physics and radiation medicine.

Energetic neutron and gamma-ray spectra under the earth radiation belts according to "SALYUT-7" [correction of "SALUTE-7"]-"KOSMOS-1686" orbital complex and "CORONAS-I" satellite data.

PubMed

Bogomolov, A V; Dmitriev, A V; Myagkova, I N; Ryumin, S P; Smirnova, O N; Sobolevsky, I M

1998-01-01

The spectra of neutrons >10 MeV and gamma-rays 1.5-100 MeV under the Earth Radiation Belts, restored from the data, obtained onboard orbital complex "SALYUT-7" [correction of "SALUTE-7"]-"KOSMOS-1686", are presented. The spectra shapes are similar to those for albedo neutrons and gamma-rays, but absolute values of their fluxes (0.2 cm-2 s-1 for neutrons, 0.8 cm-2 s-1 for gamma-rays at the equator and 1.2 cm-2 s-1, 1.9 cm-2 s-1, accordingly, at L=1.9) are several times as large. It is possibly explained by the fact that most of the detected particles were produced by the cosmic ray interactions with the orbital complex matter. Neutron and gamma-ray fluxes obtained from "CORONAS-1" data are near those for albedo particles.

Correlation analysis between 2D and quasi-3D gamma evaluations for both intensity-modulated radiation therapy and volumetric modulated arc therapy

PubMed Central

Kim, Jung-in; Choi, Chang Heon; Wu, Hong-Gyun; Kim, Jin Ho; Kim, Kyubo; Park, Jong Min

2017-01-01

The aim of this work was to investigate correlations between 2D and quasi-3D gamma passing rates. A total of 20 patients (10 prostate cases and 10 head and neck cases, H&N) were retrospectively selected. For each patient, both intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans were generated. For each plan, 2D gamma evaluation with radiochromic films and quasi-3D gamma evaluation with fluence measurements were performed with both 2%/2 mm and 3%/3 mm criteria. Gamma passing rates were grouped together according to delivery techniques and treatment sites. Statistical analyses were performed to examine the correlation between 2D and quasi-3D gamma evaluations. Statistically significant difference was observed between delivery techniques only in the quasi-3D gamma passing rates with 2%/2 mm. Statistically significant differences were observed between treatment sites in the 2D gamma passing rates (differences of less than 8%). No statistically significant correlations were observed between 2D and quasi-3D gamma passing rates except the VMAT group and the group including both IMRT and VMAT with 3%/3 mm (r = 0.564 with p = 0.012 for theVMAT group and r = 0.372 with p = 0.020 for the group including both IMRT and VMAT), however, those were not strong. No strong correlations were observed between 2D and quasi-3D gamma evaluations. PMID:27690300

Observational capabilities of solar satellite "Coronas-Photon"

NASA Astrophysics Data System (ADS)

Kotov, Yu.

Coronas-Photon mission is the third satellite of the Russian Coronas program on solar activity observation The main goal of the Coronas-Photon is the study of solar hard electromagnetic radiation in the wide energy range from UV up to high energy gamma-radiation sim 2000MeV Scientific payload for solar radiation observation consists of three type of instruments 1 monitors Natalya-2M Konus-RF RT-2 Penguin-M BRM Phoka Sphin-X Sokol for spectral and timing measurements of full solar disk radiation with timing in flare burst mode up to one msec Instruments Natalya-2M Konus-RF RT-2 will cover the wide energy range of hard X-rays and soft Gamma rays 15keV to 2000MeV and will together constitute the largest area detectors ever used for solar observations Detectors of gamma-ray monitors are based on structured inorganic scintillators with energy resolution sim 5 for nuclear gamma-line band to 35 for GeV-band PSD analysis is used for gamma neutron separation for solar neutron registration T 30MeV Penguin-M has capability to measure linear polarization of hard X-rays using azimuth are measured by Compton scattering asymmetry in case of polarization of an incident flux For X-ray and EUV monitors the scintillation phoswich detectors gas proportional counter CZT assembly and Filter-covered Si-diodes are used 2 Telescope-spectrometer TESIS for imaging solar spectroscopy in X-rays with angular resolution up to 1 in three spectral lines and RT-2 CZT assembly of CZT

The Hematopoietic Syndrome of the Acute Radiation Syndrome in Rhesus Macaques: A Systematic Review of the Lethal Dose Response Relationship.

PubMed

MacVittie, Thomas J; Farese, Ann M; Jackson, William

2015-11-01

Well characterized animal models that mimic the human response to potentially lethal doses of radiation are required to assess the efficacy of medical countermeasures under the criteria of the U.S. Food and Drug Administration "animal rule." Development of a model requires the determination of the radiation dose response relationship and time course of mortality and morbidity across the hematopoietic acute radiation syndrome. The nonhuman primate, rhesus macaque, is a relevant animal model that may be used to determine the efficacy of medical countermeasures to mitigate major signs of morbidity and mortality at selected lethal doses of total body irradiation. A systematic review of relevant studies that determined the dose response relationship for the hematopoietic acute radiation syndrome in the rhesus macaque relative to radiation quality, dose rate, and exposure uniformity has never been performed. The selection of data cohorts was made from the following sources: Ovid Medline (1957-present), PubMed (1954-present), AGRICOLA (1976-present), Web of Science (1954-present), and U.S. HHS REPORT (2002 to present). The following terms were used: Rhesus, total body-irradiation, total body x irradiation, TBI, irradiation, gamma radiation, hematopoiesis, LD50/60, Macaca mulatta, whole-body irradiation, nonhuman primate, NHP, monkey, primates, hematopoietic radiation syndrome, mortality, and nuclear radiation. The reference lists of all studies, published and unpublished, were reviewed for additional studies. The total number of hits across all search sites was 3,001. There were a number of referenced, unpublished, non-peer reviewed government reports that were unavailable for review. Fifteen studies, 11 primary (n = 863) and four secondary (n = 153) studies [n = 1,016 total nonhuman primates (NHP), rhesus Macaca mulatta] were evaluated to provide an informative and consistent review. The dose response relationships (DRRs) were determined for uniform or non-uniform total body irradiation (TBI) with 250 kVp or 2 MeV x radiation, Co gamma radiation and reactor- and nuclear weapon-derived mixed gamma: neutron-radiation, delivered at various dose rates from a total body, bilateral, rotational, or unilateral exposure aspect. The DRRs established by a probit analysis vs. linear dose relationship were characterized by two main parameters or dependent variables: a slope and LD50/30. Respective LD50/30 values for studies that used 250 kVp x radiation (five primary studies combined, n = 338), 2 MeV x radiation, Co gamma radiation, and steady-state reactor-derived mixed gamma:neutron radiation for total body uniform exposures were 521 rad [498, 542], 671 rad [632, 715], 644 rad [613, 678], and 385 rad [357, 413]. The respective slopes were steep and ranged from 0.738 to 1.316. The DRR, LD50/30 values and slopes were also determined for total body, non-uniform, unilateral, pulse-rate exposures of mixed gamma:neutron radiation derived at reactor and nuclear weapon detonations. The LD50/30 values were, respectively, 395 rad [337, 432] and 412 rad [359, 460]. Secondary data sets of limited studies that did not describe a DRR were used to support the mid-to-high lethal dose range for the H-ARS and the threshold dose range for the concurrent acute GI ARS. The available evidence provided a reliable and extensive database that characterized the DRR for the H-ARS in young rhesus macaques exposed to 250 kVp uniform total body x radiation without the benefit of medical management. A less substantial but consistent database demonstrated the DRR for total body exposure of differing radiation quality, dose rate and non-uniform exposure. The DRR for the H-ARS is characterized by steep slopes and relative LD50/30 values that reflect the radiation quality, exposure aspect, and dose rate over a range in time from 1954-2012.

ATTENUATION OF SIMULATED FALLOUT RADIATION BY THE ROOF OF A CONCRETE BLOCKHOUSE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmoke, M.A.; Rexroad, R.E.

1961-08-01

An experiment was carried out to verify theoretical calculations of the effect of roof thickness on the radiation level inside a concrete blockhouse from a plane of gamma radiation on the roof. (auth)

Comparison of the changes of the antigenicities of a hen's egg albumin by a gamma and an electron beam irradiation

NASA Astrophysics Data System (ADS)

Lee, Ju-Woon; Seo, Ji-Hyun; Kim, Jae-Hun; Lee, Soo-Young; Byun, Myung-Woo

2007-05-01

The study was conducted to compare the radiation types of a gamma ray and an electron beam for the inhibition and reduction of a food allergy. OVA (2 mg/ml) were irradiated at 3, 5, 7 and 10 kGy. Patterns detected by the SDS-PAGE and an immunoblot showed that the intact OVA band disappeared and that it was dependant upon the radiation doses regardless of the radiation types. Binding abilities of the irradiated OVA against the monoclonal IgG and the egg allergic patients' IgE decreased due to a conformational change of the epitope, but differences from using the two different radiation types were not observed. The results indicate that both the radiation types can be used for an inhibition and a reduction of a food allergy regardless of the radiation types.

Gamma radiation effects in packaging for sterilization of health products and their constituents paper and plastic film

NASA Astrophysics Data System (ADS)

B. G. Porto, Karina Meschini; Napolitano, Celia Marina; Borrely, Sueli Ivone

2018-01-01

The integrity of materials containing packaging (natural or synthetic polymers) is essential to keep the aseptic condition of commercialized products (health care products, food and pharmaceuticals). The objective of this paper was to study gamma radiation effects (25 kGy, 40 kGy and 50 kGy) on the main properties of paper and multilayer films (polyester and polyethylene). Paper and multilayer films are components of packaging (pouches) for radiation sterilization containing medical equipment or products. Paper was the more radiation sensitive among the studied materials and radiation effects were more pronounced at brightness, pH, tearing resistance, bursting strength and tensile strength. Concerning plastic film, no pinholes were induced by radiation and the effects on the tensile strength were not significant. Although the seal strength packaging (pouches) decreased according to increasing dose, the sealing integrity was preserved.