Sample records for gamma radiation levels

  1. Simultaneous measurement of neutron and gamma-ray radiation levels from a TRIGA reactor core using silicon carbide semiconductor detectors

    Microsoft Academic Search

    A. R. Dulloo; F. H. Ruddy; J. G. Seidel; C. Davison; T. Flinchbaugh; T. Daubenspeck

    1998-01-01

    The ability of a SiC detector to measure neutron and gamma radiation levels in a TRIGA reactor's mixed neutron\\/gamma field was demonstrated. Linear responses to an epicadmium neutron fluence rate (up to 3×107 cm-2 s-1) and to a gamma dose rate (0.6-234 krad-Si h-1) were obtained with the detector. Axial profiles of the reactor core's neutron and gamma-ray radiation levels

  2. gamma. radiation effects on Collembola

    SciTech Connect

    Loring, S.J.

    1985-12-01

    Pitfall traps were used to collect surface-active Collembola at intervals of 10-100 m from a ..gamma.. radiation source on Long Island, N.Y., during the summer of 1968. Thirty-two species of Collembola were collected along the radiation transect. Community diversities were similar at all intervals except 10 m. Collembola appeared resistant to ..gamma.. radiation; only chronic, very high ..gamma.. radiation exposure seriously affected population levels and community diversity of surface Collembola.

  3. Measurements of gamma radiation levels and spectra in the San Francisco Bay Area

    NASA Astrophysics Data System (ADS)

    Lo, B. T.; Brozek, K. P.; Angell, C. T.; Norman, E. B.

    2011-10-01

    Much of the radiation received by an average person is emitted by naturally-occurring radioactive isotopes from the thorium, actinium, and uranium decay series, or potassium. In this study, we have measured gamma radiation levels at various locations in the San Francisco Bay Area and the UC Berkeley campus from spectra taken using an ORTEC NOMAD portable data acquisition system and a large-volume coaxial HPGe detector. We have identified a large number of gamma rays originating from natural sources. The most noticeable isotopes are 214Bi, 40K, and 208Tl. We have observed variations in counting rates by factors of two to five between different locations due to differences in local conditions - such as building, concrete, grass, and soil compositions. In addition, in a number of outdoor locations, we have observed 604-, 662-, and 795-keV gamma rays from 134,137Cs, which we attribute to fallout from the recent Fukushima reactor accident. The implications of these results will be discussed. This work was supported in part by a grant from the U. S. Dept. of Homeland Security.

  4. Estimation of {sup 237}U Level Density and Radiative Strength Functions from the (n-bar,{gamma}) Reaction

    SciTech Connect

    Sukhovoj, Anatoly M.; Khitrov, Valery A. [Joint Institute for Nuclear Research, Dubna, Russia, 141980 (Russian Federation); Maslov, Vladimir M. [Joint Institute for Nuclear and Energy Research, Minsk-Sosny, Belarus, 220109 (Belarus)

    2009-01-28

    Intensity distribution of the primary {gamma}-transitions following resonance neutron capture in {sup 236}U about the mean value was approximated in different energy intervals of these quanta and neutrons. Extrapolation of the obtained functions to zero registration threshold of {gamma}-transitions allowed independent estimation of the expected level number of both parities for spin values J = 1/2, 3/2 and sum of radiative widths for both electric and magnetic gamma-transitions to levels with excitation energy up to {approx_equal}2.3 MeV.

  5. Study of radiation dose induced by cosmic-ray origin low-energy gamma rays and electrons near sea level

    NASA Astrophysics Data System (ADS)

    Mrdja, D.; Bikit, I.; Bikit, K.; Slivka, J.; Anicin, I.

    2015-02-01

    For a long time, it has been known that low-energy continuous gamma radiation is present in open air at the Earth's surface. In previous investigations it was assumed that this radiation is produced almost exclusively by gamma photons emitted due to the natural radioactivity, which are backscattered by air above ground. We show that significant amount of this radiation (related to energy region 30-300 keV) that peaks at about 90 keV, is produced by cosmic-rays, with the photon flux of about 3000 m-2 s-1. We find that the contribution of this omnipresent low-energy gamma radiation of cosmic-ray origin, including the corresponding low-energy electron flux, to the doses of general population are non-negligible components of overall doses induced by cosmic rays near sea level.

  6. Effect of gamma radiation on the ripening and levels of bioactive amines in bananas cv. Prata

    NASA Astrophysics Data System (ADS)

    Gloria, Maria Beatriz A.; Adão, Regina C.

    2013-06-01

    Green Prata bananas at the full three-quarter stage were exposed to gamma radiation at doses of 0.0 (control), 1.0, 1.5 and 2.0 kGy and stored at 16±1 °C and 85% relative humidity. Samples were collected periodically and analyzed for peel color, pulp-to-peel ratio and levels of starch, soluble sugars and bioactive amines. Degradation of starch and formation of fructose and glucose followed first- and zero-order kinetics, respectively. Higher irradiation doses caused increased inhibitory effect on starch degradation and glucose formation. However, doses of 1.5 and 2.0 kGy caused browning of the peel, making the fruit unacceptable. Irradiation at 1.0 kGy was the most promising dose: it did not affect peel color, the pulp-to-peel ratio or the levels of the amines spermidine, serotonin and putrescine. However, it slowed down starch degradation and the formation and accumulation of fructose and glucose, delaying the ripening of the fruit for 7 days.

  7. Effects of increased shielding on gamma-radiation levels within spacecraft

    NASA Astrophysics Data System (ADS)

    Haskins, P. S.; McKisson, J. E.; Weisenberger, A. G.; Ely, D. W.; Ballard, T. A.; Dyer, C. S.; Truscott, P. R.; Piercey, R. B.; Ramayya, A. V.; Camp, D. C.

    The Shuttle Activation Monitor (SAM) experiment was flown on the Space Shuttle Columbia (STS-28) from 8 - 13 August, 1989 in a 57°, 300 km orbit. One objective of the SAM experiment was to determine the relative effect of different amounts of shielding on the gamma-ray backgrounds measured with similarly configured sodium iodide (NaI) and bismuth germante (BGO) detectors. To achieve this objective twenty-four hours of data were taken with each detector in the middeck of the Shuttle on the ceiling of the airlock (a high-shielding location) as well as on the sleep station wall (a low-shielding location). For the cosmic-ray induced background the results indicate an increased overall count rate in the 0.2 to 10 MeV energy range at the more highly shielded location, while in regions of trapped radiation the low shielding configuration gives higher rates at the low energy end of the spectrum.

  8. Measurement of gamma radiation levels in soil samples from Thanjavur using ?-ray spectrometry and estimation of population exposure

    PubMed Central

    Senthilkumar, B.; Dhavamani, V.; Ramkumar, S.; Philominathan, P.

    2010-01-01

    This study assesses the level of terrestrial gamma radiation and associated dose rates from the naturally occurring radionuclides 232Th, 238U and 40K in 10 soil samples collected from Thanjavur (Tamil Nadu, India) using ?-ray spectrometry. The activity profile of radionuclides has clearly showed the existence of low level activity in Thanjavur. The geometric mean activity concentrations of 232Th, 238U and 40K is 42.9±9.4 Bq.kg?1, 14.7±1.7 Bq.kg?1 and 149.5±3.1 Bq.kg?1 respectively are derived from all the soil samples studied. The activity concentration of 232Th, 238U and 40K in soil is due to the presence of metamorphic rocks like shale, hornblende-biotite gneiss and quartzofeldspathic gneiss in these areas. Gamma absorbed dose rates in air outdoors were calculated to be in the range between 32 nGy.h?1 and 59.1 nGy.h?1 with an arithmetic mean of 43.3 ±9 nGy.h?1. This value is lesser than the population weighted world-averaged of 60 nGy.h?1. Inhabitants of Thanjavur are subjected to external gamma radiation exposure (effective dose) ranging between 39.2 and 72.6 ?Sv.y?1 with an arithmetic mean of 53.1±11 ?Sv.y?1. The values of the external hazard index determined from the soil radioactivity of the study area are less than the recommended safe levels. PMID:20177570

  9. Gamma radiation field intensity meter

    DOEpatents

    Thacker, Louis H. (Knoxville, TN)

    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.

  10. 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.

  11. Gamma radiation field intensity meter

    DOEpatents

    Thacker, Louis H. (Knoxville, TN)

    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.

  12. 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.

  13. Unraveling low-level gamma radiation--responsive changes in expression of early and late genes in leaves of rice seedlings at Iitate Village, Fukushima.

    PubMed

    Hayashi, Gohei; Shibato, Junko; Imanaka, Tetsuji; Cho, Kyoungwon; Kubo, Akihiro; Kikuchi, Shoshi; Satoh, Kouji; Kimura, Shinzo; Ozawa, Shoji; Fukutani, Satoshi; Endo, Satoru; Ichikawa, Katsuki; Agrawal, Ganesh Kumar; Shioda, Seiji; Fukumoto, Manabu; Rakwal, Randeep

    2014-01-01

    In the summer of 2012, 1 year after the nuclear accident in March 2011 at the Fukushima Daiichi nuclear power plant, we examined the effects of gamma radiation on rice at a highly contaminated field of Iitate village in Fukushima, Japan. We investigated the morphological and molecular changes on healthy rice seedlings exposed to continuous low-dose gamma radiation up to 4 µSv h(-1), about 80 times higher than natural background level. After exposure to gamma rays, expression profiles of selected genes involved in DNA replication/repair, oxidative stress, photosynthesis, and defense/stress functions were examined by RT-PCR, which revealed their differential expression in leaves in a time-dependent manner over 3 days (6, 12, 24, 48, and 72 h). For example, OsPCNA mRNA rapidly increased at 6, 12, and 24 h, suggesting that rice cells responded to radiation stress by activating a gene involved in DNA repair mechanisms. At 72 h, genes related to the phenylpropanoid pathway (OsPAL2) and cell death (OsPR1oa) were strongly induced, indicating activation of defense/stress responses. We next profiled the transcriptome using a customized rice whole-genome 4×44K DNA microarray at early (6h) and late (72 h) time periods. Low-level gamma radiation differentially regulated rice leaf gene expression (induced 4481 and suppressed 3740 at 6 h and induced 2291 and suppressed 1474 genes at 72 h) by at least 2-fold. Using the highly upregulated and downregulated gene list, MapMan bioinformatics tool generated diagrams of early and late pathways operating in cells responding to gamma ray exposure. An inventory of a large number of gamma radiation-responsive genes provides new information on novel regulatory processes in rice. PMID:25124817

  14. Measurement of terrestrial gamma radiation dose-rate (TGRD) level in soil samples from the district of Rembau, Malaysia, using high-purity Germanium detectors

    NASA Astrophysics Data System (ADS)

    Norbani, N. E.; Abdullah Salim, N. A.; Rahman, A. T. Abdul

    2014-11-01

    This study assesses the gamma radiation levels and associated dose rates from the naturally occurring radionuclides 232Th, 238U and 40K in soil samples collected from the district of Rembau, Malaysia using High-purity Germanium (HPGe) Detectors. A 105 measurement were performed on surface soil using NaI (Tl) gamma-ray detector with crystal size 1"x1", covering about 83% land of the Rembau district. The concentration of the naturally occurring radionuclides 232Th, 238U and 40K in soil samples collected were determined by using HPGe detector based on high-resolution gamma spectrometry system at Malaysia Nuclear Agency. The range of natural gamma radiation measured was from 114±14 nGy h?1 to 857±14 nGy h?1. The range of activity concentrations of U, Th and °K in soil from the studied areas varies from 151-401 Bq kg?1, 113-342 Bq kg?1 and 674-1526 Bq kg?1 with mean values of 245 Bq kg?1, 186 Bq kg?1 and 1152 Bq kg1 respectively. The mean values of terrestrial gamma radiation dose rate measured in Rembau district is 383±18 nGy h?1 compared to the Malaysian average is 92 nGy h?1 and world average is 59 nGy h?1 (UNSCEAR, 2000). The average annual dose from such terrestrial gamma radiation dose rates to an individual in Rembau district, assuming a tropical rural setting is estimated to be 0.78 mSv per year, which is considered to be within the normal range for doses from natural sources. An isodose map for the Rembau district has been plotted.

  15. SURVEY OF THE RADIATION LEVELS IN THE CONTAINMENT VESSEL OF THE ENRICO FERMI ATOMIC POWER PLANT. PART V. GAMMA RADIATION LEVELS ON THE OPERATING FLOOR OF THE CONTAINMENT BUILDING. a. LEVELS ABOVE THE EQUIPMENT COMPARTMENT. Technical Memorandum No. 16

    Microsoft Academic Search

    W. F. Chaltron; H. E. Hungerford

    1959-01-01

    The results are presented of a survey of calculated gamma-ray levels at ;\\u000a many points on the surface of the operating floor of the containment building for ;\\u000a the Enrico Fermi reactor. That portion of the floor surveyed lies directly above ;\\u000a the equipment compartment. The calculations were made with the aid of an IBM-650 ;\\u000a electronic computer. The main

  16. Gamma radiation characteristics of plutonium dioxide fuel

    NASA Technical Reports Server (NTRS)

    Gingo, P. J.

    1969-01-01

    Investigation of plutonium dioxide as an isotopic fuel for Radioisotope Thermoelectric Generators yielded the isotopic composition of production-grade plutonium dioxide fuel, sources of gamma radiation produced by plutonium isotopes, and the gamma flux at the surface.

  17. Virtual Gamma Ray Radiation Sources through Neutron Radiative Capture

    SciTech Connect

    Scott Wilde, Raymond Keegan

    2008-07-01

    The countrate response of a gamma spectrometry system from a neutron radiation source behind a plane of moderating material doped with a nuclide of a large radiative neutron capture cross-section exhibits a countrate response analogous to a gamma radiation source at the same position from the detector. Using a planar, surface area of the neutron moderating material exposed to the neutron radiation produces a larger area under the prompt gamma ray peak in the detector than a smaller area of dimensions relative to the active volume of the gamma detection system.

  18. Gamma radiation exposure of MCT diode arrays

    Microsoft Academic Search

    F. F. Sizov; I. O. Lysiuk; J. V. Gumenjuk-Sichevska; S. G. Bunchuk; V. V. Zabudsky

    2006-01-01

    Investigations of electrical properties of long-wavelength infrared (LWIR) mercury cadmium telluride arrays exposed to gamma-radiation have been performed. Resistance-area product characteristics of LWIR n+-p-photodiodes have been investigated using a microprobe technique at T ap 78 K before and after exposure to various doses of gamma-radiation (Co60 Gammas). The current transport mechanisms for those structures are described within the framework of

  19. Radiation Sterilization and Food Irradiation Using Gamma Radiation

    NASA Astrophysics Data System (ADS)

    O'Hara, Kevin

    2003-03-01

    Since the introduction of MDS Nordion's first irradiator in the early 1960's, a variety of gamma-processing systems has been developed. Each design is suited to a particular set of requirements - from high-throughput operations of diverse product lots to full automation or batch processing, all using gamma radiation. Gamma irradiator designs include the Centurion irradiator for temperature-sensitive food products like hamburgers and poultry; the Brevion, a compact batch irradiator providing flexibility, timeliness and simplicity on a whole new scale; a JS-10000 irradiator that operates in either automatic or batch mode to enable multipurpose product scheduling and optimum throughput; and, an irradiator that processes full pallets and is ideal for processing high-density products requiring excellent dose uniformity. These innovative irradiator designs help facilities to be more efficient, maximize operating time, improve product turnaround and minimize inventory levels. MDS Nordion's development of improved Point Kernel and Monte Carlo techniques is discussed, including their application in radiation source optimization, production irradiator design and process control. Absorbed-dose calculations also provide insight into the critical areas for dose mapping and routine monitoring, allowing for the optimum placement of dosimeters. Calculations may also be used to determine the absorbed-dose distribution within product, especially in areas of complex geometry such as material interfaces. The use of easily accessible, accurate and validated dose-calculation programs can be used to optimize the irradiation process. Key Words: dosimetry, irradiator design, dose calculation, modelling, modeling, process control, radiation source optimization.

  20. Non Invasive Water Level Monitoring on Boiling Water Reactors Using Internal Gamma Radiation: Application of Soft Computing Methods

    Microsoft Academic Search

    Sebastian Fleischer; Rainer Hampel

    2006-01-01

    To provide best knowledge about safety-related water level values in boiling water reactors (BWR) is essentially for operational regime. For the water level determination hydrostatic level measurement systems are almost exclusively applied, because they stand the test over many decades in conventional and nuclear power plants (NPP). Due to the steam generation especially in BWR a specific phenomenon occurs which

  1. Spatial distribution of gamma radiation levels in surface soils from Jaduguda uranium mineralization zone, Jharkhand, India, using ?-ray spectrometry, and determination of outdoor dose to the population

    PubMed Central

    Maharana, Mandakini; Krishnan, Narayani; Sengupta, D.

    2010-01-01

    The concentrations of natural radionuclides in surface soil samples around selected villages of Jaduguda were investigated and compared with the radioactivity level in the region. Concentrations of 238U, 232Th, and 40K were determined by a gamma ray spectrometer using the HPGe detector with 50% relative efficiency, and the radiation dose to the local population was estimated. The average estimated activity concentrations of 238U, 232Th, and 40K in the surface soil were 53.8, 44.2 and 464.2 Bq kg?1 respectively. The average absorbed dose rate in the study area was estimated to be 72.5 nGy h-1, where as the annual effective dose to the population was 0.09 mSv y-1. A correlation analysis was made between measured dose rate and individual radionuclides, in order to delineate the contribution of the respective nuclides towards dose rate. The radio-elemental concentrations of uranium, thorium and potassium estimated for the soils, in the study area, indicated the enrichment of uranium series nuclide. The results of the present study were subsequently compared with international and national recommended values. PMID:21170189

  2. 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.

  3. 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. PMID:11906138

  4. Annual effective dose from environmental gamma radiation in Bushehr city

    PubMed Central

    2014-01-01

    Background Present study was an attempt to measure outdoor and indoor gamma dose rates in Bushehr city to determine corresponding annual effective dose and, to assess effect of active nuclear power plant located in Bushehr city on background radiation level of this city. Methods All measurements were performed by G.M (Geiger Muller) detector (X5C plus) calibrated in Iran Atomic Energy Agency. In order to avoid effects of ground on outdoor and indoor measurements, G.M detector was placed one meter higher than ground level. Also, during the outdoor measurements, G.M detector was used at least six meters away from the walls of any building nearby to avoid unwanted effects of the materials used in the buildings on measurements. Results Average gamma dose rates of outdoor and indoor measurements were determined as 51.8?±?8.8 nSv/h and 60.2?±?7.2 nSv/h, respectively. Annual effective dose due to background gamma radiation was calculated as 0.36 mSv which was lower than average global level. Conclusions The average annual effective dose from background gamma radiation in Bushehr city was less than global level. Comparison of the results of present study, as follow up, with previous attempt performed in 2004 to determine effective dose of environmental gamma radiation in Bushehr province revealed that, during eight years, nuclear power plant located in this city has not significantly increased level of annual effective dose of Bushehr city. PMID:24393421

  5. High range gamma radiation meter

    SciTech Connect

    Baird, W.; Bjarke, D.; Eisen, Y.

    1986-02-01

    A low power meter has been constructed and tested to measure gamma fields from .1 R/h to 1500 R/h over the energy range of 60 keV to 1.2 MeV. The portable, battery-powered meter consists of a local display unit and remote probe. The display unit indicates gamma intensities via a 4-1/2 digit liquid crystal display (LCD) and a 50-segment bargraph LCD.

  6. High range gamma radiation meter

    SciTech Connect

    Baird, W.; Bjarke, G.O.; Eisen, Y.

    1985-01-01

    A low power meter has been constructed and tested to measure gamma fields from .1 R/hr to 1500 R/hr over the energy range of 60 keV to 1.2 MeV. The portable, battery-powered meter consists of a local display unit and remote probe. The display unit indicates gamma intensities via a 4-1/2 digit liquid crystal display (LCD) and a 50-segment bargraph LCD.

  7. Satellite observation of atmospheric nuclear gamma radiation

    Microsoft Academic Search

    John R. Letaw; G. H. Share; R. L. Kinzer; R. Silberberg; E. L. Chupp; D. J. Forrest; E. Rieger

    1989-01-01

    The authors present a satellite observation of the spectrum of gamma radiation from the Earth's atmosphere in the energy interval from 300 keV to 8.5 MeV. The data were accumulated by the gamma ray spectrometer on the Solar Maximum Mission over 3 1\\/2 years, from 1980 to 1983. The excellent statistical accuracy of the data allows 20 atmospheric line features

  8. Determination and Mitigation of Precipitation Effects on Portal Monitor Gamma Background Levels 

    E-print Network

    Revis, Stephen

    2012-07-16

    The purpose of this project is to establish a correlation between precipitation and background gamma radiation levels at radiation portal monitors (RPM) deployed at various ports worldwide, and to devise a mechanism by which the effects...

  9. Low-level gamma-ray spectrometry

    SciTech Connect

    Brodzinski, R.L.

    1990-10-01

    Low-level gamma-ray spectrometry generally equates to high-sensitivity gamma-ray spectrometry that can be attained by background reduction, selective signal identification, or some combination of both. Various methods for selectively identifying gamma-ray events and for reducing the background in gamma-ray spectrometers are given. The relative magnitude of each effect on overall sensitivity and the relative cost'' for implementing them are given so that a cost/benefit comparison can be made and a sufficiently sensitive spectrometer system can be designed for any application without going to excessive or unnecessary expense. 10 refs., 8 figs.

  10. Gamma radiation background measurements from Spacelab 2

    NASA Technical Reports Server (NTRS)

    Paciesas, William S.; Gregory, John C.; Fishman, Gerald J.

    1989-01-01

    A Nuclear Radiation Monitor incorporating a NaI(Tl) scintillation detector was flown as part of the verification flight instrumentation on the Spacelab 2 mission, July 29 to August 6, 1985. Gamma-ray spectra were measured with better than 20 s resolution throughout most of the mission in the energy range 0.1 to 30 MeV. Knowledge of the decay characteristics and the geomagnetic dependence of the counting rates enable measurement of the various components of the Spacelab gamma-ray background: prompt secondary radiation, earth albedo, and delayed induced radioactivity. The status of the data analysis and present relevant examples of typical background behavior are covered.

  11. Gamma radiation background measurements from Spacelab 2

    NASA Technical Reports Server (NTRS)

    Paciesas, William S.; Gregory, John C.; Fishman, Gerald J.

    1988-01-01

    A Nuclear Radiation Monitor incorporating a NaI(Tl) scintillation detector was flown as part of the verification flight instrumentation on the Spacelab 2 mission, July 29 to August 6, 1985. Gamma-ray spectra were measured with better than 20 s resolution throughout most of the mission in the energy range 0.1 to 30 MeV. Knowledge of the decay characteristics and the geomagnetic dependence of the counting rates enable measurement of the various components of the Spacelab gamma-ray background: prompt secondary radiation, Earth albedo, and delayed induced radioactivity. The status of the data analysis and present relevant examples of typical background behavior are covered.

  12. Gamma ray emission from radiative supernova remnants

    NASA Astrophysics Data System (ADS)

    Asvarov, Abdul

    In this presentation we have considered Gamma-ray emission from supernova remnants (SNRs) evolving in high density environments, for which the radiative phase of evolution is more typical. Gamma-rays from such objects are believed to have hadronic origin, i.e. as a result of decay of neutral pi-mesons, created in the p-p collisions of relativistic hadrons (protons, etc.) with interstellar medium protons. DSA mechanism is considered as the main mechanism of acceleration of relativistic particles. We assume that SNR evolves in more or less homogeneous interstellar medium. This is contrary to two main models of origin of Gamma-rays from shell type SNRs, which are: 1) Runaway CR model which considers Gamma-ray emission from molecular clouds illuminated by runaway CRs that have escaped from the SNRs; 2) Crushed Cloud model, which considers the shocked interstellar clouds being responsible for the gamma-ray emission of the SNR. The considered model gives the largest conversion rate of SN energy to gamma-rays. It has been found that under certain (close to real) conditions considered here type of SNRs can easily provide the flux of gamma-rays with energies > 100 MeV, typical for the large number of unidentified sources listed in the recent Fermi LAT source catalog. We have obtained conditions under which SNRs are better observable in gamma-rays than in other bands of the electromagnetic spectrum.

  13. Gamma Radiation Doses In Sweden

    SciTech Connect

    Almgren, Sara; Isaksson, Mats [Department of Radiation Physics, Goeteborg University, Sahlgrenska University Hospital, SE-413 45 Goeteborg (Sweden); Barregaard, Lars [Department of Occupational and Environmental Medicine, Sahlgrenska Hospital and Academy, SE-405 30 Goeteborg (Sweden)

    2008-08-07

    Gamma dose rate measurements were performed in one urban and one rural area using thermoluminescence dosimeters (TLD) worn by 46 participants and placed in their dwellings. The personal effective dose rates were 0.096{+-}0.019(1 SD) and 0.092{+-}0.016(1 SD){mu}Sv/h in the urban and rural area, respectively. The corresponding dose rates in the dwellings were 0.11{+-}0.042(1 SD) and 0.091{+-}0.026(1 SD){mu}Sv/h. However, the differences between the areas were not significant. The values were higher in buildings made of concrete than of wood and higher in apartments than in detached houses. Also, {sup 222}Rn measurements were performed in each dwelling, which showed no correlation with the gamma dose rates in the dwellings.

  14. Radiolysis of sulfoxides. [Gamma radiation

    Microsoft Academic Search

    V. N. Korobeinikova; G. G. Bikbaeva; Yu. I. Murinov; Yu. E. Nikitin; V. P. Kazadov

    2009-01-01

    A study was made on the extractability of petroleum sulfoxides (PSO) and their closest analog tetramethylene sulfoxide (TMSO) upon ..gamma.. irradiation. A two-phase system was used, one phase being either neat PSO or diluted with twice its amount of o-xylene and the other an aqueous solution of UOâ(NOâ)â in 0.1 M HNOâ, with a 1:1 ratio by volume of the

  15. Gamma radiation effects on peanut skin antioxidants.

    PubMed

    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

  16. 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

  17. Inspection of cargo containers using gamma radiation

    NASA Astrophysics Data System (ADS)

    Hussein, Esam M. A.; Gokhale, Prasad; Arendtsz, Nina V.; Lawrence, Andre H.

    1997-02-01

    This paper investigate, with the aid of Monte Carlo simulations and laboratory experiments, a technique for the detection of narcotics in large cargo containers using gamma-radiation. The transmission and back-scattering of photons, at different energies, is used to provide information useful for identifying the presence of bulk quantities of commonly encountered narcotics.

  18. LATTICE DYNAMICS NUCLEAR RESONANCE ABSORPTION OF GAMMA-RADIATION

    E-print Network

    Paris-Sud XI, Université de

    LATTICE DYNAMICS NUCLEAR RESONANCE ABSORPTION OF GAMMA-RADIATION AND COHERENT DECAY MODES Institut effets de correlation de paires. Abstract. -The cross-section for nuclear resonance absorption of gamma-radiation rksonnante des radiations gamma est en gBneral calculee en negligeant I'influence des phenomknes de coherence

  19. 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.

  20. SSPM Scintillator Readout for Gamma Radiation Detection

    SciTech Connect

    Baker, S A; Wendelberger, B; Young, J A; Green, J A; Guise, R E; Franks, L

    2011-09-01

    Silicon-based photodetectors offer several benefits relative to photomultiplier tube–based scintillator systems. Solid-state photomultipliers (SSPM) can realize the gain of a photomultiplier tube (PMT) with the quantum efficiency of silicon. The advantages of the solid-state approach must be balanced with adverse trade-offs, for example from increased dark current, to optimize radiation detection sensitivity. We are designing a custom SSPM that will be optimized for green emission of thallium-doped cesium iodide (CsI(Tl)). A typical field gamma radiation detector incorporates thallium doped sodium iodide (NaI(Tl)) and a radiation converter with a PMT. A PMT’s sensitivity peaks in the blue wavelengths and is well matched to NaI(Tl). This paper presents results of photomultiplier sensitivity relative to conventional SSPMs and discusses model design improvements. Prototype fabrications are in progress.

  1. Field Deployable Gamma Radiation Detectors for DHS Use

    SciTech Connect

    Sanjoy Mukhopadhyay

    2007-08-31

    Recently, the U.S. 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 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’s 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™, which primarily uses sodium iodide crystals (3.18-cm x 2.54-cm cylinders) as gamma detector, 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™ that enables emergency personnel to obtain real-time technical analysis of radiation samples they find in the field. 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 (comparable to that of a 7.62-cm x 7.62-cm sodium iodide crystal at low gamma energy ranging from 30 keV to 3,000 keV), better resolution (< 3.0 percent at 662 keV), 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 auto triggers 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.

  2. Characterization of gamma radiation inducible thioredoxin h from Spirogyra varians.

    PubMed

    Yoon, Minchul; Yang, Ho-Yeon; Lee, Seung-Sik; Kim, Dong-Ho; Kim, Gwang-Hoon; Choi, Jong-il

    2013-08-15

    In this study, thioredoxin h (Trxh) was isolated and characterized from the fresh water green alga Spirogyra varians, which was one amongst the pool of proteins induced upon gamma radiation treatment. cDNA clones encoding S. varians thioredoxin h were isolated from a pre-constructed S. varians cDNA library. Trxh had a molecular mass of 13.5kDa and contained the canonical WCGPC active site. Recombinant Trxh showed the disulfide reduction activity, and exhibited insulin reduction activity. Also, Trxh had higher 5,5'-dithiobis(2-nitrobenzoic acid) reduction activity with Arabidopsis thioredoxin reductase (TR) than with Escherichia coli TR. Specific expression of the Trxh gene was further analyzed at mRNA and protein levels and was found to increase by gamma irradiation upto the absorbed dose of 3kGy, suggesting that Trxh may have potential functions in protection of biomolecules from gamma irradiation. PMID:23830452

  3. Terrestrial gamma radiation dose study to determine the baseline for environmental radiological health practices in Melaka state, Malaysia

    Microsoft Academic Search

    Ahmad Termizi Ramli; Sallehudin Sahrone; Husin Wagiran

    2005-01-01

    Environmental terrestrial gamma radiation dose rates were measured throughout Melaka, Malaysia, over a period of two years, with the objective of establishing baseline data on the background radiation level. Results obtained are shown in tabular, graphic and cartographic form. The values of terrestrial gamma radiation dose rate vary significantly over different soil types and for different underlying geological characteristics present

  4. Optical Sensors for Monitoring Gamma and Neutron Radiation

    NASA Technical Reports Server (NTRS)

    Boyd, Clark D.

    2011-01-01

    For safety and efficiency, nuclear reactors must be carefully monitored to provide feedback that enables the fission rate to be held at a constant target level via adjustments in the position of neutron-absorbing rods and moderating coolant flow rates. For automated reactor control, the monitoring system should provide calibrated analog or digital output. The sensors must survive and produce reliable output with minimal drift for at least one to two years, for replacement only during refueling. Small sensor size is preferred to enable more sensors to be placed in the core for more detailed characterization of the local fission rate and fuel consumption, since local deviations from the norm tend to amplify themselves. Currently, reactors are monitored by local power range meters (LPRMs) based on the neutron flux or gamma thermometers based on the gamma flux. LPRMs tend to be bulky, while gamma thermometers are subject to unwanted drift. Both electronic reactor sensors are plagued by electrical noise induced by ionizing radiation near the reactor core. A fiber optic sensor system was developed that is capable of tracking thermal neutron fluence and gamma flux in order to monitor nuclear reactor fission rates. The system provides near-real-time feedback from small- profile probes that are not sensitive to electromagnetic noise. The key novel feature is the practical design of fiber optic radiation sensors. The use of an actinoid element to monitor neutron flux in fiber optic EFPI (extrinsic Fabry-Perot interferometric) sensors is a new use of material. The materials and structure used in the sensor construction can be adjusted to result in a sensor that is sensitive to just thermal, gamma, or neutron stimulus, or any combination of the three. The tested design showed low sensitivity to thermal and gamma stimuli and high sensitivity to neutrons, with a fast response time.

  5. Radiation chemistry of aqueous solutions of cyanamide. [Gamma radiation

    Microsoft Academic Search

    Z. D. Draganic; I. G. Draganic; S. V. Jovanovic

    1978-01-01

    Oxygen-free aqueous solutions of 0.1 M NHâCN (pH 2.4 and 5) were irradiated with ..gamma.. rays (0.01--25 Mrad). The rate constants determined in competition experiments are: k(H + NHâCN) = 6.7 x 10⁶ M⁻¹ sec⁻¹, k(e\\/sub aq\\/⁻ + NHâCN) = 1.5 x 10⁹ M⁻¹ sec⁻¹, and k(OH + NHâCN) = 8.5 x 10⁶ M⁻¹ sec⁻¹. Radiation-chemical yields were determined for

  6. Gamma radiation effects on nestling Tree Swallows

    SciTech Connect

    Zach, R.; Mayoh, K.R.

    1984-10-01

    The sensitivity of Tree Swallows (Tachycineta bicolor) to the stress of ionizing radiation was investigated with growth analysis. Freshly hatched nestlings were temporarily removed from nests, taken to the laboratory and acutely exposed to 0.9, 2.7, or 4.5 Gy gamma radiation. Some of the unirradiated control nestlings were also taken to the laboratory whereas others were left in the nests. Growth of all the nestlings was measured daily and analyzed by fitting growth models. There was no detectable radiation-induced mortality up to fledgling, approx. = 20 d after irradiation. Radiation exposure did not affect the basic growth pattern; the logistic growth model was most suitable for body mass and foot length, and the von Bertalanffy model for primary-feather length, irrespective of treatment. Parameter values from these models indicated pronounced growth depression in the 2.7-Gy and 4.5-Gy groups, particularly for body mass. Radiation also affected the timing of development. The growth depression of the 2.7-Gy group was similar to that caused by hatching asynchrony in unirradiated nestlings. The 4.5-Cy nestlings grew as well as unexposed nestlings that died from natural causes. Chronic irradiation at approx. = 1.0 Cy/d caused more severe growth effects than acute exposure to 4.5 Gy and may have caused permanent stunting. Growth analysis is a potent tool for assessing man-made environmental stresses. Observed body-mass statistics and model parameters seem to be most sensitive to environmental stresses, but coefficients of variation are not necessarily correlated with sensitivity. 34 references, 2 figures, 4 tables.

  7. Orchid flowers tolerance to gamma-radiation

    NASA Astrophysics Data System (ADS)

    Kikuchi, Olivia Kimiko

    2000-03-01

    Cut flowers are fresh goods that may be treated with fumigants such as methyl bromide to meet the needs of the quarantine requirements of importing countries. Irradiation is a non-chemical alternative to substitute the methyl bromide treatment of fresh products. In this research, different cut orchids were irradiated to examine their tolerance to gamma-rays. A 200 Gy dose did inhibit the Dendrobium palenopsis buds from opening, but did not cause visible damage to opened flowers. Doses of 800 and 1000 Gy were damaging because they provoked the flowers to drop from the stem. Cattleya irradiated with 750 Gy did not show any damage, and were therefore eligible for the radiation treatment. Cymbidium tolerated up to 300 Gy and above this dose dropped prematurely. On the other hand, Oncydium did not tolerate doses above 150 Gy.

  8. Carbohydrate based materials for gamma radiation shielding

    NASA Astrophysics Data System (ADS)

    Tabbakh, F.; Babaee, V.; Naghsh-Nezhad, Z.

    2015-05-01

    Due to the limitation in using lead as a shielding material for its toxic properties and limitation in abundance, price or non-flexibility of other commonly used materials, finding new shielding materials and compounds is strongly required. In this conceptual study carbohydrate based compounds were considered as new shielding materials. The simulation of radiation attenuation is performed using MCNP and Geant4 with a good agreement in the results. It is found that, the thickness of 2 mm of the proposed compound may reduce up to 5% and 50% of 1 MeV and 35 keV gamma-rays respectively in comparison with 15% and 100% for the same thickness of lead.

  9. EURAMET.RI(I)-S7 comparison of alanine dosimetry systems for absorbed dose to water measurements in gamma- and x-radiation at radiotherapy levels

    NASA Astrophysics Data System (ADS)

    Garcia, Tristan; Anton, Mathias; Sharpe, Peter

    2012-01-01

    The National Physical Laboratory (NPL), the Physikalisch-Technische Bundesanstalt (PTB) and the Laboratoire National Henri Becquerel (LNE-LNHB) are involved in the European project 'External Beam Cancer Therapy', a project of the European Metrology Research Programme. Within this project, the electron paramagnetic resonance (EPR)/alanine dosimetric method has been chosen for performing measurements in small fields such as those used in IMRT (intensity modulated radiation therapy). In this context, these three National Metrology Institutes (NMI) wished to compare the result of their alanine dosimetric systems (detector, modus operandi etc) at radiotherapy dose levels to check their consistency. This EURAMET.RI(I)-S7 comparison has been performed with the support of the Bureau International des Poids et Mesures (BIPM) which collected and distributed the results as a neutral organization, to ensure the comparison was 'blind'. Irradiations have been made under reference conditions by each laboratory in a 60Co beam and in an accelerator beam (10 MV or 12 MV) in a water phantom of 30 cm × 30 cm × 30 cm in a square field of 10 cm × 10 cm at the reference depth. Irradiations have been performed at known values of absorbed dose to water (Dw) within 10% of nominal doses of 5 Gy and 10 Gy, i.e. between 4.5 Gy and 5.5 Gy and between 9 Gy and 11 Gy, respectively. Each participant read out their dosimeters and assessed the doses using their own protocol (calibration curve, positioning device etc) as this comparison aims at comparing the complete dosimetric process. The results demonstrate the effectiveness of the EPR/alanine dosimetry systems operated by National Metrology Institutes as a method of assuring therapy level doses with the accuracy required. The maximum deviation in the ratio of measured to applied dose is less than 1%. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by EURAMET, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  10. High Level Waste Tank Gamma Profiling paper

    SciTech Connect

    FRANK, MOORE

    2005-01-24

    Cleanup at the Savannah River Site brings with it the need to clean out and close down the radioactive waste tanks constructed in support of the fuel rod dissolution process. An innovative technique for assaying waste tanks has been developed at the Savannah River Site. The technique uses a gamma detector in the annular space between the inner and outer tank walls of double walled tanks. Unique shielding, counting electronics, and deployment techniques were developed. The system provides information to facilitate mapping interstitial liquid levels, sludge layers and other structures in the waste tank located near the tank walls. The techniques used, results, and lessons learned will be discussed.

  11. Accumulation of Mn(II) in Deinococcus radiodurans Facilitates GammaRadiation Resistance

    Microsoft Academic Search

    Michael J. Daly; E Gaidamakova; V Matrosova; A Vasilenko; M Zhai; Amudhan Venkateswaran; M Hess; M V. Omelchenko; Heather M. Kostandarithes; S Makarova; L. P. Wackett; Jim K. Fredrickson; D Ghosal

    2004-01-01

    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

  12. Interaction of deep impurities with radiation defects in n-Si at gamma-irradiation

    NASA Astrophysics Data System (ADS)

    Makhkamov, S.; Karimov, M.; Khakimov, Z. M.; Odilova, N. D.; Makhmudov, S. A.; Kurbanov, A. O.; Begmatov, K. A.

    2005-08-01

    This work presents the results of research on peculiarities of radiation defect formation in single crystal n-Si, doped by deep level impurities (Cu, Ni, Ir, Rh, Pt and Au), at irradiation by gamma-quanta of 60 Co. A property of gamma-irradiation to create only vacancies and self-interstitial atoms is used to understand the nature of deep levels with participation of these impurities and primary elemental radiation defects. The role of covalence radii and diffusion coefficients in efficiency of radiation defect formation is discussed.

  13. Pulsar and diffuse contributions to the observed galactic gamma radiation

    NASA Technical Reports Server (NTRS)

    Harding, A. K.; Stecker, F. W.

    1980-01-01

    With the acquisition of satellite data on the energy spectrum of galactic gamma-radiation, it is clear that such radiation has a multicomponent nature. A calculation of the pulsar gamma ray emission spectrum is used together with a statistical analysis of recent data on 328 known pulsars to make a new determination of the pulsar contribution to galactic gamma ray emission. The contributions from diffuse interstellar cosmic ray induced production mechanisms to the total emission are then reexamined. It is concluded that pulsars may account for a significant fraction of galactic gamma ray emission.

  14. Do altered activities of superoxide dismutases and the level of NF-?B modulate the effects of gamma radiation in HeLaS3 cells?

    Microsoft Academic Search

    MIROSLAV AD I?; SNE ANA D. SPASI?; MARIJA B. RADOJ?I?

    Most experimental models, including cell culture studies, have demon- strated that over-expression of manganese superoxide dismutase (MnSOD) in cells bearing a carcinoma phenotype has anti-proliferative and tumour suppression chara- cteristics. In contrast, when cervical carcinoma biopsies express MnSOD, there is a poor prognosis and resistance to radiation therapy. The results herein indicate that human cervical adenocarcinoma (HeLaS3) cells have increased

  15. An integrated view of gamma radiation effects on marine fauna: from molecules to ecosystems.

    PubMed

    Won, Eun-Ji; Dahms, Hans-U; Kumar, K Suresh; Shin, Kyung-Hoon; Lee, Jae-Seong

    2014-11-11

    Accidental release of nuclides into the ocean is causing health risks to marine organisms and humans. All life forms are susceptible to gamma radiation with a high variation, depending on various physical factors such as dose, mode, and time of exposure and various biological factors such as species, vitality, age, and gender. Differences in sensitivity of gamma radiation are also associated with different efficiencies of mechanisms related to protection and repair systems. Gamma radiation may also affect various other integration levels: from gene, protein, cells and organs, population, and communities, disturbing the energy flow of food webs that will ultimately affect the structure and functioning of ecosystems. Depending on exposure levels, gamma radiation induces damages on growth and reproduction in various organisms such as zooplankton, benthos, and fish in aquatic ecosystems. In this paper, harmful effects of gamma-irradiated aquatic organisms are described and the potential of marine copepods in assessing the risk of gamma radiation is discussed with respect to physiological adverse effects that even affect the ecosystem level. PMID:25382502

  16. Inhaled /sup 147/Pm and/or total-body gamma radiation: Early mortality and morbidity in rats

    SciTech Connect

    Filipy, R.E.; Lauhala, K.E.; McGee, D.R.; Cannon, W.C.; Buschbom, R.L.; Decker, J.R.; Kuffel, E.G.; Park, J.F.; Ragan, H.A.; Yaniv, S.S.; Scott, B.R.

    1989-05-01

    Rats were given doses of /sup 60/Co gamma radiation and/or lung burdens of /sup 147/Pm (in fused aluminosilicate particles) within lethal ranges in an experiment to determine and compare morbidity and mortality responses for the radiation insults within 1 year after exposure. Radiation-induced morbidity was assessed by measuring changes in body weights, hematologic parameters, and pulmonary-function parameters. Acute mortality and morbidity from inhaled promethium were caused primarily by radiation pneumonitis and pulmonary fibrosis that occurred more than 53 days after exposure. Acute mortality and morbidity from total-body gamma irradiation occurred within 30 days of exposure and resulted from the bone-marrow radiation syndrome. Gamma radiation caused transient morbidity, reflected by immediately depressed blood cell levels and by reduced body weight gain in animals that survived the acute gamma radiation syndrome. Inhaled promethium caused a loss of body weight and diminished pulmonary function, but its only effect on blood cell levels was lymphocytopenia. Combined gamma irradiation and promethium lung burdens were synergistic, in that animals receiving both radiation insults had higher morbidity and mortality rates than would be predicted based on the effect of either kind of radiation alone. Promethium lung burdens enhanced the effect of gamma radiation in rats within the first 30 days of exposure, and gamma radiation enhanced the later effect of promethium lung burdens. 70 refs., 68 figs., 21 tabs.

  17. Gamma Radiation Induced Degradation of Operating Quantum Dot Lasers

    Microsoft Academic Search

    J. W. Mares; J. Harben; A. V. Thompson; D. W. Schoenfeld; W. V. Schoenfeld

    2008-01-01

    The degradation of quantum dot lasers (QDLs) due to 1.17 and 1.22 MeV gamma radiation is characterized by changes in threshold current, external slope efficiency and light output. Both operating and non-operating lasers were exposed to a Co-60 source, providing gamma radiation at a dose rate of 0.4 kGy\\/hr to a total absorbed dose of 1.6 MGy. Degradation rates of

  18. 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.

  19. Breeding biology of Tree Swallows and House Wrens in a gradient of gamma radiation

    Microsoft Academic Search

    R. Zach; K. R. Mayoh

    1982-01-01

    In a gradient of gamma radiation from 38.7 mC kg⁻¹.d⁻¹ to background levels of 0.05 ..mu..C. kg⁻¹ . d⁻¹ to background levels of 0.05 ..mu..C . kg⁻¹ . d⁻¹, Tree Swallows (Iridoprocne bicolor) and House Wrens (Troglodytes aedon) avoided nesting in areas of high radiation. Nest boxes selected by swallows and wrens had a mean exposure rate of only 9.3

  20. Snowpack snow water equivalent measurement using the attenuation of cosmic gamma radiation

    SciTech Connect

    Osterhuber, R. [Univ. of California, Soda Springs, CA (United States). Central Sierra Snow Lab.; Fehrke, F. [California Dept. of Water Resources, Sacramento, CA (United States); Condreva, K. [Sandia National Labs., Livermore, CA (United States)

    1998-05-01

    Incoming, background cosmic radiation constantly fluxes through the earth`s atmosphere. The high energy gamma portion of this radiation penetrates many terrestrial objects, including the winter snowpack. The attenuation of this radiation is exponentially related to the mass of the medium through which it penetrates. For the past three winters, a device measuring cosmic gamma radiation--and its attenuation through snow--has been installed at the Central Sierra Snow Laboratory, near Donner Pass, California. This gamma sensor, measuring energy levels between 5 and 15 MeV, has proved to be an accurate, reliable, non-invasive, non-mechanical instrument with which to measure the total snow water equivalent of a snowpack. This paper analyzes three winters` worth of data and discusses the physics and practical application of the sensor for the collection of snow water equivalent data from a remote location.

  1. Semiconductors in the nuclear weapon gamma radiation environment. I - Prediction of gamma radiation effects. II - Verification of predictions

    Microsoft Academic Search

    A. R. Edwards; M. A. Hardman; R. Williamson

    1985-01-01

    The effects of gamma radiation on the performance of MOS and NMOS devices is considered. The different methods used to predict the ability of an IC to survive a hostile nuclear environment are described including latch-up analysis and topographic analysis. A formula is derived for predicting the failure probability of an IC in relation to the radiation dose in rads.

  2. Variation of terrestrial gamma radiation in Toki, Japan—comparison between gamma-ray spectrometry using Ge semiconductor and ICP-MS measurement

    Microsoft Academic Search

    Y. Fujikawa; M. Fukui; T. Baba; T. Yoshimoto; E. Ikeda; M. Saito; H. Yamanishi; T. Uda

    2005-01-01

    The cause of the spatial variation in external radiation levels in the Toki area in Japan was investigated by in-situ measurements of gamma-ray spectrum and by collections and measurements of soil samples. It was found that the radionuclide contents of topsoil largely governed the radiation level while land exploitation, gardening activities, and concrete-building constructions caused the variation in radiation there.

  3. Radiation Level Changes at RAM Package Surfaces

    SciTech Connect

    Opperman, Erich [Washington Savannah River Company] [Washington Savannah River Company; Hawk, Mark B [ORNL] [ORNL; Kapoor, Ashok [U.S. Department of Energy, Office of Packaging and Transportation] [U.S. Department of Energy, Office of Packaging and Transportation; Natali, Ronald [R. B. Natali Consulting, Inc.] [R. B. Natali Consulting, Inc.

    2010-01-01

    This paper will explore design considerations required to meet the regulations that limit radiation level variations at external surfaces of radioactive material (RAM) packages. The radiation level requirements at package surfaces (e.g. TS-R-1 paragraphs 531 and 646) invoke not only maximum radiation levels, but also strict limits on the allowable increase in the radiation level during transport. This paper will explore the regulatory requirements by quantifying the amount of near surface movement and/or payload shifting that results in a 20% increase in the radiation level at the package surface. Typical IP-2, IP-3, Type A and Type B packaging and source geometries will be illustrated. Variations in surface radiation levels are typically the result of changes in the geometry of the surface due to an impact, puncture or crush event, or shifting and settling of radioactive contents.

  4. Effects of low-level radiation

    SciTech Connect

    Goldman, M. [Univ. of California, Davis, CA (United States)

    1993-12-31

    The effects of low-level radiation inhumans are usually estimated by extrapolation from high-level effects. Biological radiation effects from low-level radiation can be defined as those from doses below which no deterministic or graded biological responses will occur. In addition, the health consequences are almost all probabilistic. There is incomplete knowledge regarding the role of sex, age at exposure, co-factors, or environmental pollutants.

  5. High resolution room temperature ionization chamber xenon gamma radiation detector

    Microsoft Academic Search

    Gary Tepper; Jon Losee

    1995-01-01

    A unique thin walled dual-type gridded ionization chamber gamma radiation detector using ultra pure Xe gas as the detection medium is described. The detector was operated at room temperature and the energy spectra of 60Co, 137Cs, 22Na and 133Ba were obtained. An energy resolution of (16 keV) 2.4% FWHM was determined for the 662 keV 137Cs gamma peak which is

  6. Radiative Transfer Models for Gamma-Ray Bursts

    E-print Network

    Vurm, Indrek

    2015-01-01

    We present global radiative transfer models for heated relativistic jets. The simulations include all relevant radiative processes, starting deep in the opaque zone and following the evolution of radiation to and beyond the photosphere of the jet. The transfer models are compared with three gamma-ray bursts GRB 990123, GRB 090902B, and GRB 130427A, which have well-measured and different spectra. The models provide good fits to the observed spectra in all three cases. The fits give estimates for the jet magnetization parameter $\\varepsilon_{\\rm B}$ and the Lorentz factor $\\Gamma$. In the small sample of three bursts, $\\varepsilon_{\\rm B}$ varies between 0.01 and 0.1, and $\\Gamma$ varies between 340 and 1200.

  7. A study of the diffuse galactic gamma radiation

    NASA Technical Reports Server (NTRS)

    Fichtel, C. E.; Kniffen, D. A.

    1982-01-01

    Assuming cosmic rays pervade the Galaxy, they necessarily produced high energy gamma-rays as they interact with the instellar matter and photons. The cosmic ray nucleon interactions five rise to gamma rays primarily through the decay of pi mesons, giving a unique spectrum with a maximum at approximately 68 MeV. Cosmic ray electrons produce gamma rays through bremsstrahlung, but with a markedly different energy spectral shape, one which decreases monotonically with energy. Cosmic ray electrons also interact with the interstellar starlight, optical and infrared photons, and the blackbody radiation through the Compton process. A model of galactic gamma ray production is discussed, and the predicted spatial distribution and energy spectra are presented. Considering the uncertainty in the point source contributions, the agreement between the theoretical predictions and the gamma ray data seems quite reasonable.

  8. Polymer Composites for Radiation Detection: Di-iodobenzene and light emitting polymer molecular solutions for gamma detection

    SciTech Connect

    Qibing Pei; Yongsheng Zhao; Haizheng Zhong [University of California, Los Angeles, California (United States)

    2008-07-01

    Conjugated polymers are largely intact by gamma exposure but can be energized in the presence of high-Z compounds. The resulting alteration of the polymer's high optical density and photoluminescence efficiency can be exploited for the detection of gamma radiation with high sensitivity. Di-iodobenzene and conjugated polymers mix on the molecular level in solid thin films. Composite films of various thicknesses were conveniently cast from solution and exposed to gamma radiation. The responses of the films to gamma dosage were observed with dramatic changes in ultraviolet-visible absorption and photoluminescence. (authors)

  9. Effect of gamma radiation on dentin bond strength and morphology.

    PubMed

    Sperandio, M; Souza, J B; Oliveira, D T

    2001-01-01

    Sterilization by gamma radiation is a method often used for bone and extracted teeth banking. The bond strength of human dentin submitted to gamma rays has not been reported. Therefore, the aim of this study was to assess the effect of gamma radiation on dentin shear bond strength and morphology. The roots were removed from extracted human bicuspids and their crowns divided into two groups: an untreated control and crowns submitted to gamma radiation sterilization. The crowns were mounted in epoxy resin and the buccal enamel removed exposing the subjacent dentin. SBMPPlus adhesive system was applied to a 3-mm diameter area after 15 s of 35% phosphoric acid etching. The samples were mounted in composite resin cylinders and stored in distilled water at 37 degrees C for 24 h until the shear test. Dental fragments from both groups were prepared for SEM analysis. There was no statistically significant difference between the results of the shear test for the two groups according to the Tukey test (p > 0.05). Scanning electron micrographs also did not show alterations. These results indicate that gamma radiation neither affected the shear bond strength of SBMPPlus nor altered the dentin surface morphology. PMID:11696920

  10. Gamma line radiation from supernovae. [nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Arnett, W. D.

    1978-01-01

    Recent calculations of core collapse or massive stars result in explosive ejection of the mantle by a reflected shock. These hydrodynamic results are important for predictions of explosive nucleosynthesis and gamma-ray line emission from supernovae. Previous estimates, based on simple parameterized models or the nucleosynthesis in an average supernova, are compared with these latest results.

  11. Measurements of background gamma radiation on Spacelab 2

    NASA Technical Reports Server (NTRS)

    Fishman, G. J.; Paciesas, W. S.; Gregory, J. C.

    1987-01-01

    A nuclear radiation monitor (NRM) which was flown as part of the verification instrumentation on the Spacelab 2 mission (July 29 - August 6, 1985) recorded spectra every 20 seconds and counting rates in coarse energy bands on finer time scales. The gamma radiation environment on Spacelab is characterized by cosmic-ray and trapped proton secondary radiation in the Spacelab/Shuttle, earth albedo radiation, and delayed induced radioactivity in the detector and surrounding materials. It is found that passages through South Atlantic Anomaly protons produce a well-defined background enhancement.

  12. Investigation of {gamma} radiation from {sup 178}Hf in the respective (n, n Prime {gamma}) reaction

    SciTech Connect

    Govor, L. I.; Demidov, A. M.; Kurkin, V. A., E-mail: kurkin@polyn.kiae.su; Mikhailov, I. V. [National Research Center Kurchatov Institute (Russian Federation)

    2012-12-15

    The spectra and angular distributions of gamma rays were measured in the reaction {sup 178}Hf(n, n Prime {gamma}) induced by a beam of fast reactor neutrons. Data onmultipole mixtures in gamma transitions and a lot of new information about gamma transitions of energy 1.5 to 3.0 MeV were obtained. A comparison of these results with information known from the respective (n, {gamma}) reaction made it possible to refine the schemes of deexcitation of {sup 178}Hf levels at energies above 1.5 MeV, to determine more precisely features of these levels, and to introduce new levels and rotation bands at excitation energies of about 2MeV.

  13. GRABGAM Analysis of Ultra-Low-Level HPGe Gamma Spectra

    SciTech Connect

    Winn, W.G.

    1999-07-28

    The GRABGAM code has been used successfully for ultra-low level HPGe gamma spectrometry analysis since its development in 1985 at Savannah River Technology Center (SRTC). Although numerous gamma analysis codes existed at that time, reviews of institutional and commercial codes indicated that none addressed all features that were desired by SRTC. Furthermore, it was recognized that development of an in-house code would better facilitate future evolution of the code to address SRTC needs based on experience with low-level spectra. GRABGAM derives its name from Gamma Ray Analysis BASIC Generated At MCA/PC.

  14. GAMMA RADIATION TREATMENT OF WATERS FROM LIGNITE MINES

    EPA Science Inventory

    Discussed in this report are results of laboratory investigations carried out with the application of gamma radiation for the purification of waters drained from surface lignite mines. These waters are polluted to a considerable extent with suspended matter of various sizes, a la...

  15. The Effects of Co60 Gamma Radiation on MOS Diodes

    Microsoft Academic Search

    R. J. Mattauch; R. W. Lade

    1967-01-01

    MOS diodes were fabricated on silicon substrates and exposed to Co60 gamma radiation. A change in both surface state density and oxide charge density was noted. Non-irradiation annealing studies were carried out to determine the nature of the oxide charge. It was deduced on the basis of annealing data that the oxide charge was due to mobile alkali ions. The

  16. The role of contacts in semiconductor gamma radiation detectors

    Microsoft Academic Search

    Uri Lachish

    1998-01-01

    It is proposed that the operation of semiconductor gamma radiation detectors, equipped with ohmic contacts, which allow free electron flow between the contacts and bulk material, will not be sensitive to low hole mobility, hole collection efficiency, or hole trapping. Such fast-operating detectors may be readily integrated into monolithic arrays. The detection mechanism and various material aspects are discussed and

  17. Thermal Radiation from Gamma-ray Burst Jets

    Microsoft Academic Search

    Akira Mizuta; Shigehiro Nagataki; Junichi Aoi

    2011-01-01

    In this study, the light curves and spectrum of the photospheric thermal radiation from ultrarelativistic gamma-ray burst (GRB) jets are calculated using two-dimensional relativistic hydrodynamic simulations of jets from a collapsar. As the jet advances, the density around the head of the jet decreases, and its Lorentz factor reaches as high as 200 at the photosphere and 400 inside the

  18. Integrated beta and gamma radiation dose calculations for the ferrocyanide waste tanks

    SciTech Connect

    Parra, S.A.

    1994-11-30

    This report contains the total integrated beta and gamma radiation doses in all the ferrocyanide waste tanks. It also contains estimated gamma radiation dose rates for all single-shell waste tanks containing a liquid observation well.

  19. Phototherapeutic Effect of Low-Level Laser on Thyroid Gland of Gamma-Irradiated Rats.

    PubMed

    Morcos, Nadia; Omran, Manar; Ghanem, Hala; Elahdal, Mahmoud; Kamel, Nashwa; Attia, Elbatoul

    2015-07-01

    One inescapable feature of life on the earth is exposure to ionizing radiation. The thyroid gland is one of the most sensitive organs to gamma-radiation and endocrine disrupters. Low-level laser therapy (LLLT) has been used to stimulate tissue repair, and reduce inflammation. The aim of this study was to gauge the value of using Helium-Neon laser to repair the damaged tissues of thyroid gland after gamma-irradiation. Albino rats were used in this study (144 rats), divided into control, gamma, laser, and gamma plus laser-irradiated groups, each group was divided into six subgroups according to time of treatment (total six sessions). Rats were irradiated once with gamma radiation (6 Gy), and an external dose of laser (Wavelength 632.8 nm, 12 mW, CW, Illuminated area 5.73 cm(2) , 2.1 mW cm(-2) , 120 s, 1.4 J, 0.252 J cm(-2) ) twice weekly localized on thyroid region of the neck, for a total of six sessions. Animals were sacrificed after each session. Analysis included thyroid function, oxidative stress markers, liver function and blood picture. Results revealed improvement in thyroid function, liver function and antioxidant levels, and the blood cells count after LLLT. PMID:25975382

  20. 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.; Kaspi, V. M.; Kniffen, D. A.; Kuiper, L.; Lin, Y. C.; Lyne, A.; Manchester, R.; Matz, S. M.; Mayer-Hasselwander, H. A.; Michelson, P. F.; Nolan, P. L.

    1998-01-01

    The telescopes on the Compton Gamma Ray Observatory (CCRO) have observed PSR B1055-52 a number of times between 1991 and 1998. From these data, a more detailed picture of the gamma radiation from this source has been developed, showing several characteristics which distinguish this pulsar: the light curve is complex; there is no detectable unpulsed emission; the energy spectrum is flat, with no evidence of a sharp high-energy cutoff up to greater than 4 GeV. Comparisons of the gamma-ray data with observations at longer wavelengths show that no two of the known gamma-ray pulsars have quite the same characteristics; this diversity makes interpretation in terms of theoretical models difficult.

  1. 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.; Kaspi, V. M.; Kniffen, D. A.; Kuiper, L.; Lin, Y. C.; Lyne, A.; Manchester, R.; Matz, S. M.; Mayer-Hasselwander, H. A.; Michelson, P. F.; Nolan, P. L.

    1999-01-01

    The telescopes on the Compton Gamma Ray Observatory (CGRO) have observed PSR B1055-52 a number of times between 1991 and 1998. From these data, a more detailed picture of the gamma radiation from this source has been developed, showing several characteristics which distinguish this pulsar: the light curve is complex; there is no detectable unpulsed emission; the energy spectrum is flat, with no evidence of a sharp high-energy cutoff up to greater than 4 GeV. Comparisons of the gamma-ray data with observations at longer wavelengths show that no two of the known gamma-ray pulsars have quite the same characteristics; this diversity makes interpretation in terms of theoretical models difficult.

  2. Attenuation of VHE Gamma Rays by the Milky Way Interstellar Radiation Field

    SciTech Connect

    Moskalenko, Igor V.; /Stanford U., HEPL; Porter, Troy A.; /Louisiana State U.; Strong, Andrew W.; /Garching, Max Planck Inst., MPE

    2006-04-19

    The attenuation of very high energy gamma rays by pair production on the Galactic interstellar radiation field has long been thought of as negligible. However, a new calculation of the interstellar radiation field consistent with multi-wavelength observations by DIRBE and FIRAS indicates that the energy density of the Galactic interstellar radiation field is higher, particularly in the Galactic center, than previously thought. We have made a calculation of the attenuation of very high energy gamma rays in the Galaxy using this new interstellar radiation field which takes into account its nonuniform spatial and angular distributions. We find that the maximum attenuation occurs around 100 TeV at the level of about 25% for sources located at the Galactic center, and is important for both Galactic and extragalactic sources.

  3. Parametric gamma-radiation at the anomalous passage conditions

    NASA Astrophysics Data System (ADS)

    Ahmadi, Abbas; Feranchuk, Ilya

    2014-10-01

    Dynamical diffraction theory of the parametric gamma-radiation (PGR) from relativistic electrons in a thick crystal with Mössbauer nuclei is considered. A detailed analysis of the influence of suppression of photoabsorption for the radiated ?-quanta at an ideal single crystal is presented taking into account both nuclear resonance and electron scattering of the photons. The obtained results allow one to choose the optimal conditions for the observation of the ?-quanta anomalous passage at the Laue case. It is shown that the radiation intensity is drastically increased at such conditions.

  4. Public exposure due to external gamma background radiation in boundary areas of Iran.

    PubMed

    Pooya, S M Hosseini; Dashtipour, M R; Enferadi, A; Orouji, T

    2015-09-01

    A monitoring program in boundary areas of a country is an appropriate way to indicate the level of public exposure. In this research, gamma background radiation was measured using TL dosimeters at 12 boundary areas as well as in the capital city of Iran during the period 2010 to 2011. The measurements were carried out in semi-annual time intervals from January to June and July to December in each year. The maximum average dose equivalent value measured was approximately 70 ?Sv/month for Tehran city. Also, the average dose values obtained were less than 40 ?Sv/month for all the cities located at the sea level except that of high level natural radiation area of Ramsar, and more than 55 ?Sv/month for the higher elevation cities. The public exposure due to ambient gamma dose equivalent in Iran is within the levels reported by UNSCEAR. PMID:26057985

  5. CdTe low level gamma detectors based on a new crystal growth method

    Microsoft Academic Search

    E. Raiskin; J. F. Butler

    1988-01-01

    A new method of crystal growth, employing a high pressure, vertical Bridgman approach, was successfully applied to the growth of CdTe gamma-ray detector crystals for application to background-level, low bias dosimeters. Detectors of 1.8-mm thickness were uniformly able to detect background radiation at bias levels below 10 volts and exhibited other desirable features. The new growth method makes it possible

  6. Gamma-ray decay of levels in /sup 53/Cr

    SciTech Connect

    Dickens, J.K.; Larson, D.C.

    1987-11-01

    Gamma-ray decay of levels in the stable isotope /sup 53/Cr has been studied using /sup 53/Cr(n,n'..gamma..) reactions for incident neutron energies between threshold and 10 MeV. Of the 65 gamma rays or gamma-ray groups observed for neutron interactions with /sup 53/Cr, 50 have been placed or tentatively placed among 34 levels in /sup 53/Cr up to an excitation energy of 4.36 MeV. Deduced branching ratios are in reasonable agreement with previous measurements except for decay of the E/sub x/ = 1537-keV level. For the decay of the E/sub x/ = 1537-keV level we are unable to explain variations in the branching ratios of the transition gamma rays as a function of incident neutron energy within the framework of the presently known level structure of /sup 53/Cr and suggest the possibility of a second energy level at E/sub x/ = 1537 keV. 59 refs., 13 figs., 2 tabs.

  7. Semiconductors in the nuclear weapon gamma radiation environment. I - Prediction of gamma radiation effects. II - Verification of predictions

    NASA Astrophysics Data System (ADS)

    Edwards, A. R.; Hardman, M. A.; Williamson, R.

    The effects of gamma radiation on the performance of MOS and NMOS devices is considered. The different methods used to predict the ability of an IC to survive a hostile nuclear environment are described including latch-up analysis and topographic analysis. A formula is derived for predicting the failure probability of an IC in relation to the radiation dose in rads. The design of a linear accelerator radiation simulator for testing semiconductor devices is described, and the results of recent calibration tests are presented.

  8. Recent results on the effect of gamma radiation on the durability and microstructure of DWPF glass

    SciTech Connect

    Bibler, N.E.; Tosten, M.H.; Beam, D.C.

    1989-12-31

    The effect of gamma radiation on the durability and microstructure of a simulated nuclear waste glass from the Savannah River Site has been carefully investigated. Three large pieces of glass were irradiated with a Co-60 source to three doses up to a maximum dose of 3.1 {times} 10{sup 10} rad. Internal samples of the large pieces of irradiated and unirradiated glass were leached in deionized water to investigate durability changes and were examined by transmission electron microscopy (TEM) to investigate microstructure changes. Leach tests were performed in triplicate at 90{degree}C with crushed glass samples in deionized water. A statistical analysis of the results indicated to the 95% confidence level that the radiation did not affect the glass durability. Careful examination by TEM indicated no effect of gamma radiation on the microstructure of the glass although severe damage could be induced by the electron beam from the microscope. 19 refs., 2 figs., 3 tabs.

  9. Characterization of muon and gamma radiations at the PTOLEMY site

    NASA Astrophysics Data System (ADS)

    Betts, Susannah; Gentile, Charles; Tully, Chris; Zapata, Sandra; Chris Tully Collaboration

    2013-10-01

    PTOLEMY is an experimental project at Princeton Plasma Physics Laboratory designed to determine the present day number density of relic neutrinos through measurement of electrons produced from neutrino capture on tritium. The weak interaction cross section for relic neutrino interactions necessitates high sensitivity measurements that could be influenced by high energy particles, like muons and gamma ray photons, which induce nuclear transitions and secondary electrons. Muons produced from the collision of cosmic rays with atmospheric nuclei are a significant source of background radiation at and below Earth's surface. The muon flux is measured by the coincidence of minimum ionization radiation loss in two plastic scintillator paddles. The spectrum of gamma ray photons is measured using sodium iodide based scintillators. These measurements will provide a characterization of the background and rates at the PTOLEMY site.

  10. Gamma heating measurements in a mixed radiation field

    SciTech Connect

    Chiu, H.K. (Illinois Univ., Urbana, IL (USA). Dept. of Nuclear Engineering); Bennett, E.F.; Micklich, B.J. (Argonne National Lab., IL (USA))

    1990-09-01

    Gamma hearing measurements have been made in a low-Z assembly irradiated with 14-MeV neutrons and (n,n{prime}) gammas produced by a Texas Nuclear Model 9400 neutron generator. The assembly is composed of 144 magnesium sleeves (5cm {times} 5cm {times} 60cm {times} 3 mm thick) filled with graphite to simulate a fusion blanket test module. Heating measurements were made in the mid-line of the assembly using a proportional counter operating in the Continuously-varied Bias-voltage Acquisition (CBA) mode. The neutron induced atomic recoil signal was rejected by observing the signal rise-time differences inherent to radiations of different LET. The experiment was modelled using the one-dimensional radiation transport code ANISN/PC. The operating limits of this technique were identified by comparing measurements made at different positions in the assembly and then comparing these measurements to the calculated flux. 7 refs., 5 figs., 1 tab.

  11. 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.

  12. 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.

  13. Radiation hardness of high resistivity magnetic Czochralski silicon detectors after gamma, neutron, and proton radiations

    Microsoft Academic Search

    Zheng Li; Jaakko Harkonen; Wei Chen; J. Kierstead; Panja Luukka; Eija Tuominen; Etuovine Tuovinen; Elea Verbitskaya; Vladimir Eremin

    2004-01-01

    High resistivity magnetic Czochralski Si detectors were irradiated with 60Co gamma rays, neutrons, and protons to various doses\\/fluences, along with control float zone Si detectors. 1) It has been found that for gamma radiation, magnetic Czochralski Si detectors behave similarly to the high-temperature, long-time (HTLT) oxygenated float zone Si detectors. There is no space charge sign inversion and there is

  14. Inactivation of bacteria in sewage sludge by gamma radiation.

    PubMed

    Pandya, G A; Kapila, S; Kelkar, V B; Negi, S; Modi, V V

    1987-01-01

    The survival of certain bacterial cultures suspended in sewage sludge and exposed to gamma-radiation was studied. The inactivation patterns of most of the organisms were significantly different when irradiation was performed using sewage samples collected in the summer and monsoon seasons. The summer sample collected from the anaerobic digestor afforded significant protection to both Gram negative and Gram positive organisms. This was evident by the increase in dose required to bring about a 6 log cycle reduction in viable count of the bacterial cultures, when suspended in sewage samples instead of phosphate buffer. The observations made using monsoon digestor samples were quite different. This sewage sludge greatly enhanced inactivation by gamma-radiation in most cases. The effects of certain chemicals on the inactivation patterns of two organisms-Salmonella typhi and Shigella flexneri-were examined. Arsenate, mercury and lead salts sensitised S. typhi, while barium acetate and sodium sulphide protected this culture against gamma-radiation. In the case of Sh. flexneri, barium acetate and iodacetamide proved to be radioprotectors. The effects of some chemicals on the inactivation pattern of Sh. flexneri cells irradiated in sludge are also discussed. PMID:15092791

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

    SciTech Connect

    Daly, Michael J.; Gaidamakova, E; Matrosova, V; Vasilenko, A; Zhai, M; Venkateswaran, Amudhan; Hess, M; Omelchenko, M V.; Kostandarithes, Heather M.; Makarova, S; Wackett, L. P.; Fredrickson, Jim K.; Ghosal, D

    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.

  16. Modeling radiation effects at the tissue level

    NASA Astrophysics Data System (ADS)

    Müller, M.; Durante, M.; Stöcker, H.; Merz, F.; Bechmann, I.

    2010-10-01

    For the understanding of radiation action in humans, a synergistic approach of experiments and quantitative modeling of working hypotheses is necessary. A large set of experimental data at the single-cell level are available, and biophysical modeling of radiation action has so far mostly concentrated on the first phases of radiation interaction with the biomolecules, and later biochemical stages including DNA breakage, repair, and the formation of chromosomal aberrations. The models can be extended to cell killing and transformation, but so far still using a single-cell (clonal expansion) approach. On the contrary, new experimental evidence points to the microenvironment and the tissue level as a critical radiation target for late effects, and to epigenetic and signaling mechanisms as mediators of radiation damage. This higher structural level is generally ignored in modeling, owing to its complexity and to the lack of experimental data. In this paper we will highlight the requirements for specific experimental approaches targeting the tissue/microenvironment level and the most promising available experimental models.

  17. Effect of gamma irradiation conditions on the radiation-induced degradation of isobutylene–isoprene rubber

    Microsoft Academic Search

    M. ?en; C. Uzun; Ö. Kantoglu; S. M. Erdo?an; V. Deniz; O. Güven

    2003-01-01

    The effect of gamma irradiation conditions on the radiation-induced degradation of uncrosslinked, commercial isobutylene–isoprene rubbers has been investigated in this study. Influence of dose rate and irradiation atmosphere on the degradation of butyl rubber has been followed by viscosimetric and chromatographic analyses. Limiting viscosity number of all butyl rubbers decreased sharply up to 100 kGy and leveled off at around

  18. Impacts of Low-Dose Gamma-Radiation on Genotoxic Risk in Aquatic Ecosystems

    PubMed Central

    Cassidy, Cheryl L.; Lemon, Jennifer A.; Boreham, Douglas R.

    2007-01-01

    Chinook salmon cells were exposed to gamma radiation and chromosome damage was assessed using the micronucleus assay. The salmon cells were resistant to radiation at all doses compared to human and mammalian cells. We used an indirect approach to determine if prior low dose exposures at environmental dose levels might alter the consequences of radiation exposures to high doses of radiation (adaptive response). The cells adapted but only at doses which were above levels that might be expected environmentally. The “adaptive response” endpoint was useful to show biological responses to exposure, however, under these conditions it might not help in risk assessment of aquatic organisms since the cells seem to be very resistant and environmental radiation levels are typically extremely low. Preliminary experiments were conducted on two other fish cell model systems (Rainbow Trout and Medaka) to optimize conditions for the micronucleus assay for future environmental radiation studies. Since fish cells appear to be more radiation resistant than mammalian cells, we postulate that radiation risk in the whole organism may also be lower. Therefore whole body studies designed to test effects with the specific aim of assessing relative risk between species are in process. PMID:18648569

  19. Lightning flashes conducive to the production and escape of gamma radiation to space

    Microsoft Academic Search

    E. Williams; R. Boldi; J. Bór; G. Sátori; C. Price; E. Greenberg; Y. Takahashi; K. Yamamoto; Y. Matsudo; Y. Hobara; M. Hayakawa; T. Chronis; E. Anagnostou; D. M. Smith; L. Lopez

    2006-01-01

    Gamma radiation observed in space has been associated with lightning flashes in thunderstorms. These special flashes do not appear to be the large and energetic positive ground flashes that also produce sprites. Considerations of gamma ray attenuation in air indicate that such flashes may not produce gamma radiation at sufficient altitude to enable their escape to space. High-altitude intracloud lightning,

  20. Radiation metabolomics. 1. Identification of minimally invasive urine biomarkers for gamma-radiation exposure in mice.

    PubMed

    Tyburski, John B; Patterson, Andrew D; Krausz, Kristopher W; Slavík, Josef; Fornace, Albert J; Gonzalez, Frank J; Idle, Jeffrey R

    2008-07-01

    Gamma-radiation exposure has both short- and long-term adverse health effects. The threat of modern terrorism places human populations at risk for radiological exposures, yet current medical countermeasures to radiation exposure are limited. Here we describe metabolomics for gamma-radiation biodosimetry in a mouse model. Mice were gamma-irradiated at doses of 0, 3 and 8 Gy (2.57 Gy/min), and urine samples collected over the first 24 h after exposure were analyzed by ultra-performance liquid chromatography-time-of-flight mass spectrometry (UPLC-TOFMS). Multivariate data were analyzed by orthogonal partial least squares (OPLS). Both 3- and 8-Gy exposures yielded distinct urine metabolomic phenotypes. The top 22 ions for 3 and 8 Gy were analyzed further, including tandem mass spectrometric comparison with authentic standards, revealing that N-hexanoylglycine and beta-thymidine are urinary biomarkers of exposure to 3 and 8 Gy, 3-hydroxy-2-methylbenzoic acid 3-O-sulfate is elevated in urine of mice exposed to 3 but not 8 Gy, and taurine is elevated after 8 but not 3 Gy. Gene Expression Dynamics Inspector (GEDI) self-organizing maps showed clear dose-response relationships for subsets of the urine metabolome. This approach is useful for identifying mice exposed to gamma radiation and for developing metabolomic strategies for noninvasive radiation biodosimetry in humans. PMID:18582157

  1. Predictions of induced background radiations at gamma/X-ray experiment envelopes in NASA spacecraft

    NASA Technical Reports Server (NTRS)

    Fischbein, W. L.; Debiak, T.; Rossi, M.; Stauber, M.; Suh, P.

    1979-01-01

    This work seeks to predict secondary radiation levels induced in spacecraft structures by space protons. The radiations analyzed are secondary neutrons from spallation and evaporation reactions and gamma and beta rays from the decay of induced radioactivity, as sources of interfering background to spaceborne measurements of galactic and planetary gamma rays below 10 MeV. The spacecraft considered are the Multi-Mission Spacecraft (MMS) and the Space Shuttle, modeled as spherical shells. The proton environment is that of the South Atlantic Anomaly, as well as cosmic ray protons. The induced radioactivity is analyzed in terms of its interference with various gamma-ray lines of astrophysical interest, as well as its contribution to several spectral regions of the gamma-ray continuum. The buildup of the line and continuum radioactivity background is predicted for a period of nearly 9 months in orbit (approximately 4100 orbits). In addition, background contributions from cosmic ray electron bremsstrahlung and earth gamma-ray albedo are estimated.

  2. Health effects of low-level radiation in shipyard workers. Final report: [Draft

    SciTech Connect

    Matanoski, G.M.

    1991-06-01

    The Nuclear Shipyard Workers Study (NSWS) was designed to determine whether there is an excess risk of leukemia or other cancers associated with exposure to low levels of gamma radiation. The study compares the mortality experience of shipyard workers who qualified to work in radiation areas to the mortality of similar workers who hold the same types of jobs but who are not authorized to work in radiation areas. The population consists of workers from six government and two private shipyards.

  3. Modern Methods of Real-Time Gamma Radiation Monitoring for General Personal Protection

    NASA Astrophysics Data System (ADS)

    Korostynska, O.; Arshak, K.; Arshak, A.; Vaseashta, Ashok

    Real-time radiation detectors become an essential part of emergency personnel who may have to respond to unknown accidents, incidents or terrorist attacks, which could involve radioactive material. More and more ordinary citizens are interested in personal radiation protection as well. Reasons include lost sources, nuclear industrial accidents, nuclear or radiological terrorism and the possibility of nuclear weapons being used in a war. People want to have the ability to measure it for themselves and they want to be notified when the radiation levels are increased. To meet this demand, considerable research into new sensors is underway, including efforts to enhance the sensor performance through both the material properties and manufacturing technologies. Deep understanding of physical properties of the materials under the influence of radiation exposure is vital for the effective design of dosimeter devices. Detection of radiation is based on the fact that both the electrical and the optical properties of the materials undergo changes upon the exposure to ionizing radiation. It is believed that radiation causes structural defects. The influence of radiation depends on both the dose and the parameters of the films including their thickness: the degradation is more severe for the higher dose and the thinner films. This paper presents overview of modern methods of real-time gamma radiation monitoring for personal protection of radiation workers and general public and suggests further developments in this area.

  4. The origin of the diffuse background gamma-radiation

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.; Puget, J. L.

    1974-01-01

    Recent observations have now provided evidence for diffuse background gamma radiation extending to energies beyond 100 MeV. There is some evidence of isotropy and implied cosmological origin. Significant features in the spectrum of this background radiation have been observed which provide evidence for its origin in nuclear processes in the early stages of the big-band cosmology and tie in these processes with galaxy fromation theory. A crucial test of the theory may lie in future observations of the background radiation in the 100 MeV to 100 GeV energy range which may be made with large orbiting spark-chamber satellite detectors. A discussion of the theoretical interpretations of present data, their connection with baryon symmetric cosmology and galaxy formation theory, and the need for future observations are given.

  5. 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.

  6. Radiative decays of the Upsilon(1S) to gamma pi(0)pi(0), gamma eta eta and gamma pi(0)eta

    Microsoft Academic Search

    D. Besson; T. K. Pedlar; D. Cronin-Hennessy; K. Y. Gao; D. T. Gong; J. Hietala; Y. Kubota; T. Klein; B. W. Lang; R. Poling; A. W. Scott; A. Smith; S. Dobbs; Z. Metreveli; K. K. Seth; A. Tomaradze; P. Zweber; J. Ernst; K. Arms; H. Severini; S. A. Dytman; W. Love; S. Mehrabyan; J. A. Mueller; V. Savinov; Z. Li; A. Lopez; H. Mendez; J. Ramirez; G. S. Huang; D. H. Miller; V. Pavlunin; B. Sanghi; I. P. J. Shipsey; G. S. Adams; M. Anderson; J. P. Cummings; I. Danko; J. Napolitano; Q. He; H. Muramatsu; C. S. Park; E. H. Thorndike; T. E. Coan; Y. S. Gao; F. Liu; M. Artuso; C. Boulahouache; S. Blusk; J. Butt; J. Li; N. Menaa; S. Nisar; K. Randrianarivony; R. Redjimi; R. Sia; T. Skwarnicki; S. Stone; J. C. Wang; K. Zhang; S. E. Csorna; G. Bonvicini; D. Cinabro; M. Dubrovin; A. Lincoln; R. A. Briere; G. P. Chen; J. Chen; T. Ferguson; G. Tatishvili; H. Vogel; M. E. Watkins; J. L. Rosner; N. E. Adam; J. P. Alexander; K. Berkelman; D. G. Cassel; J. E. Duboscq; K. M. Ecklund; R. Ehrlich; L. Fields; R. S. Galik; L. Gibbons; R. Gray; S. W. Gray; D. L. Hartill; B. K. Heltsley; D. Hertz; C. D. Jones; J. Kandaswamy; D. L. Kreinick; V. E. Kuznetsov; H. Mahlke-Kruger; T. O. Meyer; P. U. E. Onyisi; J. R. Patterson; D. Peterson; E. A. Phillips; J. Pivarski; D. Riley; A. Ryd; A. J. Sadoff; H. Schwarthoff; X. Shi; S. Stroiney; W. M. Sun; T. Wilksen; M. Weinberger; S. B. Athar; P. Avery; L. Breva-Newell; R. Patel; V. Potlia; H. Stoeck; J. Yelton; P. Rubin; C. Cawlfield; B. I. Eisenstein; I. Karliner; D. Kim; N. Lowrey; P. Naik; C. Sedlack; M. Selen; E. J. White; J. Wiss; M. R. Shepherd; D. M. Asner; K. W. Edwards

    2007-01-01

    We report on a study of exclusive radiative decays of the Y(1S) resonance into the final states gamma pi(0)pi(0), gamma eta eta and gamma pi(0)eta, using 1.13 fb(-1) of e(+)e(-) annihilation data collected at root s=9.46 GeV with the CLEO III detector operating at the Cornell Electron Storage Ring. In the channel gamma pi(0)pi(0), we measure the branching ratio for

  7. Breeding biology of tree swallows and house wrens in a gradient of gamma radiation

    Microsoft Academic Search

    R. Zach; K. R. Mayoh

    1982-01-01

    In a gradient of gamma radiation ranging from 38.7 mC.kg⁻¹.d⁻¹ to background levels of 0.05 ..mu..C.kg⁻¹.d⁻¹, Tree Swallows (Iridoprocne bicolor) and House Wrens (Troglodytes aedon) avoided nesting in areas of high radiation. Nest boxes selected by swallows and wrens had a mean exposure rate of only 9.3 and 6.6 ..mu..C.kg⁻¹.d⁻¹, respectively. Lateral and canopy vegetation indices and nest hole height

  8. Gamma-ray pulsars: Radiation processes in the outer magnetosphere

    SciTech Connect

    Romani, R.W.

    1996-01-01

    The authors describe an emission model for gamma ray pulsars based on curvature radiation-reaction limited charges in the outer magnetosphere. They 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. They argue that this produces GeV pulse profiles, curvature spectra and detection statistics consistent with the observations. They 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 they comment on very high energy pulsed emission and particle production and note extensions needed to allow a more complete pulsar model.

  9. 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.

  10. Radiation sterilization of fluoroquinolones in solid state: Investigation of effect of gamma radiation and electron beam

    Microsoft Academic Search

    Babita K. Singh; Dilip V. Parwate; Indrani B. Dassarma; Sudhir K. Shukla

    2010-01-01

    The effect of gamma radiation from 60Co source and 2MeV electron beam was studied on two fluoroquinolone antibiotics viz norfloxacin and gatifloxacin in the solid state. The changes in reflectance spectrum, yellowness index, vibrational characteristics, thermal behavior, UV spectrum, chemical potency (HPLC) and microbiological potency were investigated. ESR measurement gave the number of free radical species formed and their population.

  11. Radiation hardness of plastic scintillating fiber against fast neutron and [gamma]-ray irradiation

    SciTech Connect

    Murakami, Akira; Yoshinaka, Hideki; Goto, Minehiko (Saga Univ. (Japan). Dept. of Physics)

    1993-08-01

    In future collider experiments, where a background radiation level is estimated to be very high, e.g. around 10[sup 2] [approximately] 10[sup 5] Gy/yr and 10[sup 11] [approximately] 10[sup 14] n/cm[sup 2]/yr at SSC, the detectors operating around the collision point in the experiments will encounter a considerable amount of radiation. Therefore, the detectors, especially the calorimeter, are required to be resistive against high radiation levels. From this point of view, it is of great importance to study the effects of radiation damage on the performance of the detectors. The authors report preliminary results of measurements of radiation hardness of the plastic scintillating fiber Kuraray SCSF-81 against irradiation with fast neutrons and [sup 60]Co [gamma]-rays in the region of the neutron fluence from 1 [times] 10[sup 11] to 5 [times] 10[sup 13] n/cm[sup 2] and the integrated [gamma]-ray dose from 890 to 10[sup 5] Gy, respectively. Deterioration of both intrinsic light yield and light transmittance of the SCSF-81 has been studied.

  12. Sensitometry of the response of a new radiochromic film dosimeter to gamma radiation and electron beams

    NASA Astrophysics Data System (ADS)

    McLaughlin, W. L.; Yun-Dong, Chen; Soares, C. G.; Miller, A.; Van Dyk, G.; Lewis, D. F.

    1991-04-01

    A new radiation-sensitive imaging material, called GafChromic™ Dosimetry Media, offers advances in high-dose radiation dosimetry and high-resolution radiography for gamma radiation and electrons. The potential uses in radiation processing, radiation sterilization of medical devices, population control of insects by irradiation, food irradiation, blood irradiation for organ-transplant immuno-suppression, clinical radiography, and industrial radiography have led to the present sensitometric study over the breadth of the wide dynamic range of this new routine detector and imaging material, namely, absorbed doses from 10 Gy to 5 × 10 4 Gy. The thin-coated film is colorless before irradiation, and registers a deep-blue image upon irradiation, with two absorption bands at about 650 nm (major band) and 600 nm (minor band). The response to electrons, in terms of increase in absorbance per unit absorbed dose, is the same as that to gamma radiation within the estimated uncertainty of the measurements (± 5%, 95% confidence level). The spatial resolving power is > 1200 lines/mm. After the first 24 hours, the image is stable over many months (within ± 5% in absorbance), however, the system should be irradiated and analyzed at approximately the temperatures used during calibration, because of temperature dependence during irradiation and readout, and temperatures greater than 55°C should be avoided.

  13. EFFECTS OF GAMMA RADIATION ON ELECTROCHEMICAL PROPERTIES OF IONIC LIQUIDS

    SciTech Connect

    Visser, A; Nicholas Bridges, N; Thad Adams, T; John Mickalonis, J; Mark02 Williamson, M

    2009-04-21

    The electrochemical properties of ionic liquids (ILs) make them attractive for possible replacement of inorganic salts in high temperature molten salt electrochemical processing of nuclear fuel. To be a feasible replacement solvent, ILs need to be stable in moderate and high doses of radiation without adverse chemical and physical effects. Here, we exposed seven different ILs to a 1.2 MGy dose of gamma radiation to investigate their physical and chemical properties as they related to radiological stability. The azolium-based ILs experienced the greatest change in appearance, but these ILs were chemically more stable to gamma radiation than some of the other classes of ILs tested, due to the presence of aromatic electrons in the azolium ring. All the ILs exhibited a decrease in their conductivity and electrochemical window (at least 1.1 V), both of which could affect the utility of ILs in electrochemical processing. The concentration of the irradiation decomposition products was less than 3 mole %, with no impurities detectable using NMR techniques.

  14. Plasma Gamma Globulin Levels After Splenectomy and Spleen Salvage

    PubMed Central

    Zeki, Yilmaz; Ahmet, Erkilic; Metin, Sen; Hüseyin, Kilic

    1989-01-01

    A series of plasma globulin studies was carried out on 108 patients who were operated on for splenic trauma during the last 3 years. The reasons for splenectomy or spleen salvage were; gunshot wounds in 22 patients (20.3%); stab injuries in 10 patients (9.2%) and blunt abdominal trauma in 76 patients (70.3%). Plasma gamma globulin determinations were made on the 8th postoperative day and at 3 months. In the splenectomy group; plasma gamma globulin determinations demonstrated a significant reduction in serum IgM levels (p < 0.001) but no significant changes in IgA and IgG levels (p > 0.05). No changes were detected in IgA, IgG and IgM levels in the spleen salvage group (p > 0.05). We believe that the preservation of the traumatized spleen should be the prime aim of surgeons. PMID:2487065

  15. Level densities and gamma-ray strength functions in Sn isotopes

    SciTech Connect

    Toft, H. K.; Larsen, A. C.; Buerger, A.; Guttormsen, M.; Nyhus, H. T.; Siem, S.; Syed, N. U. H. [Department of Physics, University of Oslo, N-0316 Oslo (Norway); Agvaanluvsan, U. [Stanford University, Palo Alto, California 94305 (United States); MonAme Scientific Research Center, Ulaanbaatar (Mongolia); Mitchell, G. E. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States); Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); Schiller, A.; Voinov, A. [Department of Physics, Ohio University, Athens, Ohio 45701 (United States)

    2010-06-15

    The nuclear level densities of {sup 118,119}Sn and the gamma-ray strength functions of {sup 116,118,119}Sn below the neutron separation energy are extracted with the Oslo method using the ({sup 3}He,alphagamma) and ({sup 3}He,{sup 3}He{sup '}gamma) reactions. The level-density function of {sup 119}Sn displays steplike structures. The microcanonical entropies are deduced from the level densities, and the single neutron entropy of {sup 119}Sn is determined to be 1.7 +- 0.2 k{sub B}. Results from a combinatorial model support the interpretation that some of the low-energy steps in the level density function are caused by neutron pair breaking. An enhancement in all the gamma-ray strength functions of {sup 116-119}Sn, compared to standard models for radiative strength, is observed for the gamma-ray energy region of approx =4-11 MeV. These small resonances all have a centroid energy of 8.0(1) MeV and an integrated strength corresponding to 1.7(9)% of the classical Thomas-Reiche-Kuhn sum rule. The Sn resonances may be due to electric dipole neutron skin oscillations or to an enhancement of the giant magnetic dipole resonance.

  16. Natural Radiation from Soil using Gamma-Ray Spectrometry

    SciTech Connect

    Silveira, M. A. G.; Moreira, R. H.; Paula, A. L. C. de [Centro Universitario da FEI, Sao Bernardo do Campo, Sao Paulo (Brazil); Medina, N. H. [Instituto de Fisica da Universidade de Sao Paulo, Sao Paulo (Brazil)

    2009-06-03

    We have studied the distribution of natural radioactivity in the soil of Interlagos, in Sao Paulo city and Billings Reservoir, in Sao Bernardo do Campo, Sao Paulo, Brazil. The main contribution of the effective radiation dose is due to the elements of the {sup 238}Th decay series, with smaller contributions from {sup 40}K and the elements of the series of {sup 238}U. The results indicate the dose in all of the studied areas is around the average international dose due to external exposure to gamma rays (0.48 mSv/yr) proceeding from natural terrestrial elements.

  17. Effect of gamma radiation on selected functional and physical properties of liquid egg white 

    E-print Network

    Ball, Hershell Ray

    1966-01-01

    temperature of the freezer. kfter preparation, the samples were radiated using the gamma source of the Nuclear Science Center, Texas 0, i M University. 4, constant dose rate of 600 rad. per minute of gamma radiation from a Co source was employed...EFFECT OF GAMMA RADIATION ON SELECTED FUNCTIONAL AND PHYSICAL PROPERTIES OF LIQUID EGG WHITE A Thesis By Hershell Ray Ball, Jr. Approved as to style and content by) (Chairman of Committee) ead of Department) (Me mba (Member) ( ber) ~Ja...

  18. 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

  19. Induction of mutations resistant to maize dwarf mosaic virus in Sorghum bicolor using gamma radiation

    E-print Network

    Pye, Quentin Niel

    1977-01-01

    rility in advanced generations. The NDMV snd charcoal rot, a soil- b fl K, ~Nh I ph 11 (II bl. ) A@i y, d t b1 since some MDNV resistant plants were harvested only if they were also charcoal zot resistant. The 50 krad level seems to have an Frequency... found among any of the culivars emmined in the electron microscopy study. The effects of gamma radiation were shown to increase linearly up to the 3$ krad level and curvilinearly beyond this dose with each increase in dose for M field emergence...

  20. Effect of Gamma radiation on microbial population of natural casings

    NASA Astrophysics Data System (ADS)

    Trigo, M. J.; Fraqueza, M. J.

    1998-06-01

    The high microbial load of fresh and dry natural casings increases the risk of meat product contamination with pathogenic microorganisms, agents of foodborn diseases. The aim of this work is to evaluate the killing effect of gamma radiation of the resident microbial population of pork and beef casings, to improve their hygiene and safety. Portions of fresh pork (small intestines and colon) and dry beef casings were irradiated in a Cobalt 60 source with with absorbed doses of 1,2,5 and 10 kGy. The D 10 values of total aerobic microorganisms in the pork casings were 1.65 kGy for colon and 1.54 kGy for small intestine. The D 10 value found in beef dry casings (small intestine) was 10.17 kGy. Radurization with 5 kGy was able to reduce, at least, 6 logs the coliform bacteria in pork casings. The killing effect over faecal Streptococci was 4 logs for pork fresh casings and 2 logs for beef dry casings. Gamma radiation with 5 kGy proved to be a convenient method to reduce substantially the microbial population of pork fresh casings. Otherwise, the microbial population of beef dry casings still resisted to 10 kGy.

  1. Performance of radiation survey meters in X- and gamma-radiation fields.

    PubMed

    Ceklic, Sandra; Arandjic, Danijela; Zivanovic, Milos; Ciraj-Bjelac, Olivera; Lazarevic, Djordje

    2014-11-01

    The aim of this work was to investigate the different types of radiation detectors commonly used for radiation protection purposes as survey meters. The study was performed on survey meters that use different detectors as ionisation chamber, Geiger Mueller (GM) counter and scintillation detector. For each survey meter, energy dependence and angular response in X- and gamma-radiation fields was tested. The following commercially available survey meters were investigated: ionisation chambers Victoreen 451P, Babyline 31 and VA-J-15A, Geiger counter MRK-M87, 6150 AD6 and FAG FH 40F2 and scintillation counter 6150 ADB. As a source of gamma radiation, (137)Cs and (60)Co were used whereas X-ray radiation fields were generated using an X-ray unit. The radiation characteristics of the survey meters were mostly in compliance with references estimated by standard IEC 1017-2. However, some of them showed larger deviation at lower energies. GM counters exhibit strong energy dependence for low-energy photons. PMID:25063785

  2. Delayed gamma radiation from lightning induced nuclear reactions

    NASA Astrophysics Data System (ADS)

    Greenfield, M. B.; Sakuma, K.; Ikeda, Y.; Kubo, K.

    2004-03-01

    An increase in atmospheric gamma radiation observed with NaI and Ge detectors positioned about 15 m above ground was observed following natural lightning near Tokyo, Japan [1]. Background subtracted gamma ray rates GRR following numerous lightning strokes observed since 2001 persisted for a few hours and subsequently decayed with a half-life of about 50 minutes. Using a 3x3 Ge detector, with 2 KeV resolution, positioned about 2 m from one of the NaI detectors increases in GRR were observed minutes after the onset of lightning with a delayed 50 min exponential decay. Although most of the increase in activity occured at less than a few 100 KeV, on July 11, 2003 a 1267 +/-2 KeV line was observed. Although the statistics of this event were poor, the appearance of this line with an exponential decay of 50 min half-life suggests the possibility that it may be due to 39Cl (1267 MeV; half-life = 55.5 min) via the 40Ar(gamma,p)39Cl, 40Ar(p,2p)39Cl and/or 40Ar(n,d)39Cl reactions. Observations of > 10 MeV gamma rays observed in NaI detectors within 10s of meters from and coincident with rocket-triggered lightning at the International Center for Lightning Research and Testing suggest that charged particles accelerated in intense electric fields associated with lightning give rise to photons with sufficient energy to initiate nuclear reactions [2]. Further work to explain the cause of this anomalous activity is underway using natural and triggered lightning. 1. M. B. Greenfield et al., Journal of Applied Physics 93 no. 3 (2003) pp 1839-184. 2. J. R. Dwyer et al., Science 299, (2003), pp 694-697 and recent communications

  3. Determining the Impact of Concrete Roadways on Gamma Ray Background Readings for Radiation Portal Monitoring Systems 

    E-print Network

    Ryan, Christopher Michael

    2012-07-16

    country of origin. To combat the threat of nuclear trafficking, radiation portal monitors (RPMs) are deployed around the world to intercept illicit material while in transit by passively detecting gamma and neutron radiation. Portal monitors in some...

  4. Radiation protection from whole-body gamma irradiation (6.7 Gy): behavioural effects and brain protein-level changes by an aminothiol compound GL2011 in the Wistar rat.

    PubMed

    Ganesan, Minu Karthika; Jovanovic, Milos; Secerov, Bojana; Ignjatovic, Marija; Bilban, Martin; Andjus, Pavle; Pavle, Andjus; Refaei, Amal El; Jung, Gangsoo; Li, Lin; Sase, Ajinkya; Chen, Weiqiang; Bacic, Goran; Lubec, Gert

    2014-07-01

    GL2011 is a naturally occurring thiol compound and a series of thiol compounds have been proposed as radioprotectors. Radioprotective efficacy of a triple intraperitoneal dose of GL2011 of 100 mg/kg body weight of Wistar rats, 30 min prior to and 3 and 6 h following irradiation (6.7 Gy) was evaluated. Four groups of animals were used, vehicle-treated non-irradiated (VN), GL2011-treated and irradiated (GI), GL2011-treated and non-irradiated (GN) and vehicle-treated and irradiated (VI) (n = 30 per group). The radioprotective efficacy of GL2011 was determined by measuring 28-day survival and intestinal crypt cell survival. Neuroprotection in terms of behaviour was evaluated using the behavioural observational battery, open field test and elevated plus maze paradigm. An RNA microarray was carried out in order to show differences at the RNA level between VI and VN groups. Brain protein changes were identified using a gel-based proteomics method and major brain receptor complex levels were determined by blue-native gels followed by immunoblotting. 28-Day survival rate in VI was 30 %, in GI survival was 93 %, survival of VN and GN was 100 %. Jejunal crypt cell survival was significantly enhanced in GI. Protein-level changes of peroxiredoxin-5, Mn-superoxide dismutase 2, voltage-dependent anion-selective channel protein 1, septin 5 and dopamine D2 receptor complex levels were paralleling radiation damage and protection. Taken together, the findings demonstrate that GL2011 improves survival rates and jejunal crypt survival, provides partial neuroprotection at the behavioural level and modulates proteins known to be involved in protection against oxidative stress-mediated cell damage. PMID:24682445

  5. Quantum mechanical model for nuclear-resonant scattering of gamma radiation

    Microsoft Academic Search

    Gilbert R. Hoy

    1997-01-01

    A one-dimensional quantum mechanical model for nuclear-resonant scattering of gamma radiation from matter is developed assuming the source radiation is gamma decay. A closed-form, finite-sum solution for the radiated intensity is obtained by restricting the calculation to coherent forward scattering. The solution provides a unified microscopic picture of nuclear-resonant scattering processes in which the radiation undergoes sequential scattering from one

  6. Preparation of polyester\\/gypsum\\/composite using gamma radiation, and its radiation stability

    Microsoft Academic Search

    Zaki Ajji

    2005-01-01

    Composites based on pure gypsum and polyester–styrene resin have been prepared using various doses of gamma radiation. Some physical properties of the prepared composites and the influence of irradiation dose on it have been studied as: compression strength, hardness, thermal decomposition temperature in nitrogen or oxygen, and the change in weight in aqueous solutions with different pH values.The glass transition

  7. 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.

  8. Two-year follow-up after intracoronary gamma radiation therapy

    Microsoft Academic Search

    José A Condado; Ron Waksman; Carlos Calderas; Jorge Saucedo; Alexandra Lansky

    1999-01-01

    Background. 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.Materials and Methods. To evaluate the long-term effects on clinical and angiographic outcome of endovascular gamma radiation therapy following percutaneous transluminal

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

    DOEpatents

    Hondorp, Hugh L. (Princeton Junction, NJ)

    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.

  10. Effect of acute gamma radiation on some physiological features of lichens

    Microsoft Academic Search

    M. G. Nifontova; A. P. Ravinskaya; I. A. Shapiro

    1995-01-01

    The influence of acute gamma radiation on four physiological characteristics of lichens was investigated. Membrane permeability in irradiated thalli of Cladonia arbuscula, Cetraria islandica and Hypogymnia physodes increased considerably compared to controls. The nitrogen content in Peltigera aphthosa appeared to be stable to acute gamma radiation. Up to 1000 Gy there was no essential decrease in respiration intensity in H.

  11. In situ gamma-ray spectrometry: A tutorial for environmental radiation scientists

    Microsoft Academic Search

    K. M. Miller; P. Shebell

    1993-01-01

    This tutorial is intended for those in the environmental field who perform assessments in areas where there is radioactive contamination in the surface soil. Techniques will be introduced for performing on-site quantitative measurements of gamma radiation in the environment using high resolution germanium detectors. A basic understanding of ionizing radiation principles is assumed; however, a detailed knowledge of gamma spectrometry

  12. Lightning flashes conducive to the production and escape of gamma radiation to space

    NASA Astrophysics Data System (ADS)

    Williams, E.; Boldi, R.; Bór, J.; Sátori, G.; Price, C.; Greenberg, E.; Takahashi, Y.; Yamamoto, K.; Matsudo, Y.; Hobara, Y.; Hayakawa, M.; Chronis, T.; Anagnostou, E.; Smith, D. M.; Lopez, L.

    2006-08-01

    Gamma radiation observed in space has been associated with lightning flashes in thunderstorms. These special flashes do not appear to be the large and energetic positive ground flashes that also produce sprites. Considerations of gamma ray attenuation in air indicate that such flashes may not produce gamma radiation at sufficient altitude to enable their escape to space. High-altitude intracloud lightning, most prevalent in the tropics where the tropopause is also high, may be a necessary source.

  13. Evaluation of gamma radiation shielding for nuclear waste shipping casks

    SciTech Connect

    Liu, Y.Y.; Carlson, R.D. [Argonne National Lab., IL (United States). Energy Technology Div.; Primeau, S.J. [Eagle Research Group, Inc., Germantown, MD (United States); Wangler, M.E. [Dept. of Energy, Germantown, MD (United States). Office of Transportation, Emergency Management and Analytical Services

    1998-05-01

    A method has been developed for evaluating gamma radiation shielding of shipping casks that are used to transport nuclear waste with ill-defined radionuclide contents. The method is based on calculations that establish individual limits for a comprehensive list of radionuclides in the waste, assuming that each radionuclide is uniformly distributed in a volumetric source in the cask. For multiple radionuclide mixtures, a linear fraction rule is used to restrict the total amount of radionuclides such that the sum of the fractions does not exceed 1. As long as the radionuclide limits and the linear fraction rule are followed, it can be shown that the regulatory dose rate requirements for a cask will be satisfied under normal conditions of transport and in a hypothetical accident during which the shielding thickness of the cask has been reduced by 40%.

  14. Phoswich scintillator for proton and gamma radiation of high energy

    NASA Astrophysics Data System (ADS)

    Tengblad, O.; Nilsson, T.; Borge, M. J. G.; Briz, J. A.; Carmona-Gallardo, M.; Cruz, C.; Gugliermina, V.; Nácher, E.; Perea, A.; del Rio, J. Sanchez; Nieves, M. Turrion; Johansson, H. T.; Bergström, J.; Blomberg, E.; Bülling, A.; Gallneby, E.; Hagdahl, J.; Jansson, L.; Jareteg, K.; Masgren, R.; Nordström, M.; Risting, G.; Shojaee, S.; Wittler, H.

    2011-11-01

    We present here a Phoswich scintillator design to achieve both high resolution gamma ray detection, and good efficiency for high energy protons. There are recent developments of new high resolution scintillator materials. Especially the LaBr3(Ce) and LaCl3(Ce) crystals have very good energy resolution in the order of 3% for 662 keV gamma radiation. In addition, these materials exhibit a very good light output (63 and 32 photons/keV respectively). A demonstrator detector in the form of an Al cylinder of 24 mm diameter and a total length of 80 mm with 2 mm wall thickness, containing a LaBr3(Ce) crystal of 20 mm diameter and 30 mm length directly coupled to a LaCl3(Ce) crystal of 50 mm length, and closed with a glass window of 5 mm, was delivered by Saint Gobain. To the glass window a Hamamatsu R5380 Photomultiplier tube (PMT) was coupled using silicon optical grease.

  15. \\Gamma\\Gamma \\Gamma\\Gamma

    E-print Network

    Laske, Gabi

    \\Gamma\\Gamma @@@ @@@ ### ### ### ### \\Gamma\\Gamma\\Gamma \\Gamma\\Gamma\\Gamma @@@ @@@ ### ### ### ### \\Gamma\\Gamma\\Gamma \\Gamma\\Gamma\\Gamma yyy yyy \\Gamma\\Gamma@@####\\Gamma\\Gamma@@####\\Gamma\\Gamma@@####\\Gamma\\Gamma@@####\\Gamma\\Gamma@@####\\Gamma\\Gamma\\Gamma @@@ @@@ ### ### ### ### \\Gamma\\Gamma\\Gamma \\Gamma\\Gamma\\Gamma @@@ @@@ ### ### ### ### \\Gamma\\Gamma\\Gamma \\Gamma\\Gamma\\Gamma yyy

  16. 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- V?) 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.

  17. Breeding biology of Tree Swallows and House Wrens in a gradient of gamma radiation

    SciTech Connect

    Zach, R.; Mayoh, K.R.

    1982-12-01

    In a gradient of gamma radiation from 38.7 mC kg/sup -1/.d/sup -1/ to background levels of 0.05 ..mu..C. kg/sup -1/ . d/sup -1/ to background levels of 0.05 ..mu..C . kg/sup -1/ . d/sup -1/, Tree Swallows (Iridoprocne bicolor) and House Wrens (Troglodytes aedon) avoided nesting in areas of high radiation. Nest boxes selected by swallows and wrens had a mean exposure rate of only 9.3 and 6.6 ..mu..C . kg/sup -1/ . d/sup -1/, respectively. Lateral and canopy vegetation indices and nest hole height and direction could not explain the observed pattern of box selection. Of the boxes with low exposure rates, swallows selected those with little vegetation cover, whereas wrens chose boxes and heavy cover. It appears that the birds responded to radiation levels as low as 100 times background, but it is not clear whether they actually detected radiation or simply responded to secondary clues. The number of swallows and wrens fledged per box was unrelated to radiation exposure. The same was true for number of eggs, hatching success, fledging success, incubation time, and nestling time. Breeding success was reduced because of infertile eggs, eggs with dead embryos, cracked eggs, predation, adverse weather, abandonment, and parasites. The logistic model was ideally suited for describing gains in mass in nestling swallows and wrens. Growth of nestlings was not related to radiation exposure as indicated by the growth rate constant, asymptotic mass, and the proportion of variation explained by the logistic model. Breeding and growth performance were similar in studies not involving experimental radiation.

  18. Effects of ionizing radiation (neutrons/gamma rays) on plasma lipids and lipoproteins in rats.

    PubMed

    Feurgard, C; Bayle, D; Guézingar, F; Sérougne, C; Mazur, A; Lutton, C; Aigueperse, J; Gourmelon, P; Mathé, D

    1998-07-01

    Male Wistar rats weighing 250 g were exposed to 4 Gy of neutrons/gamma radiation (3.33 Gy of neutrons and 0.66 Gy of gamma rays). After whole-body irradiation, plasma cholesterol and phospholipid levels increased up to 62 and 37%, respectively, at day 4 and then returned to control values 12 days after irradiation. Plasma triglyceride concentrations decreased concomitantly with decreased food intake after irradiation but remained higher than in pair-fed control rats. Plasma lipoproteins were separated by ultracentrifugation on a density gradient (1.006-1.210 g/ml). Four days after irradiation, most of the cholesterol (62% compared to 31% in controls, P < 0.001) is transported by apolipoprotein E-rich high-density lipoproteins. At the same time, plasma levels of apolipoproteins B and E were increased by 28 and 65%, respectively, while those of apolipoproteins AI and AIV were reduced by 21 and 59%, respectively. While in the liver of irradiated rats the apolipoprotein B/E receptor number was not modified, the hydroxymethylglutaryl coenzyme A reductase activity was fivefold higher than in control pair-fed rats. Four days after irradiation, the susceptibility of lipoproteins to peroxidation, as measured by the formation of conjugated dienes in the presence of Cu2+, was markedly increased while plasma vitamin E levels were decreased, demonstrating that irradiation reduces antioxidant stores markedly. These results suggest that such modified lipoproteins could be involved in radiation-induced vascular damage. PMID:9650601

  19. Influence on cell proliferation of background radiation or exposure to very low, chronic gamma radiation. [Paramecium tetraurelia; Synechococcus lividus

    SciTech Connect

    Planel, H.; Soleilhavoup, J.P.; Tixador, R.; Richoilley, G.; Conter, A.; Croute, F.; Caratero, C.; Gaubin, Y.

    1987-05-01

    Investigations carried out on the protozoan Paramecium tetraurelia and the cyanobacteria Synechococcus lividus, which were shielded against background radiation or exposed to very low doses of gamma radiation, demonstrated that radiation can stimulate the proliferation of these two single-cell organisms. Radiation hormesis depends on internal factors (age of starting cells) and external factors (lighting conditions). The stimulatory effect occurred only in a limited range of doses and disappeared for dose rates higher than 50 mGy/y.

  20. Effect of gamma radiation on the growth, survival, hematology and histological parameters of rainbow trout (Oncorhynchus mykiss) larvae.

    PubMed

    Oujifard, Amin; Amiri, Roghayeh; Shahhosseini, Gholamreza; Davoodi, Reza; Moghaddam, Jamshid Amiri

    2015-08-01

    Effects of low (1, 2.5 and 5Gy) and high doses (10, 20 and 40Gy) of gamma radiation were examined on the growth, survival, blood parameters and morphological changes of the intestines of rainbow trout (Oncorhynchus mykiss) larvae (103±20mg) after 12 weeks of exposure. Negative effects of gamma radiation on growth and survival were observed as radiation level and time increased. Changes were well documented at 10 and 20Gy. All the fish were dead at the dose of 40Gy. In all the treatments, levels of red blood cells (RBC), hematocrit (HCT) and hemoglobin (HB) were significantly (P<0.05) declined as the irradiation levels increased, whereas the amount of mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) did not change. No significant differences (P>0.05) were found in the levels of white blood cells (WBC), lymphocytes and monocytes. Destruction of the intestinal epithelium cells was indicated as the irradiation levels increased to 1Gy and above. The highest levels of growth, survival, specific growth rate (SGR), condition factor (CF) and protein efficiency rate (PER) were obtained in the control treatment. The results showed that gamma rays can be a potential means for damaging rainbow trout cells. PMID:26141584

  1. Sensitometry of the response of a new radiochromic film dosimeter to gamma radiation and electron beams

    Microsoft Academic Search

    W. L. McLaughlin; Chen Yun-Dong; C. G. Soares; A. Miller; G. van Dyk; D. F. Lewis

    1991-01-01

    A new radiation-sensitive imaging material, called GafChromic™ Dosimetry Media, offers advances in high-dose radiation dosimetry and high-resolution radiography for gamma radiation and electrons. The potential uses in radiation processing, radiation sterilization of medical devices, population control of insects by irradiation, food irradiation, blood irradiation for organ-transplant immuno-suppression, clinical radiography, and industrial radiography have led to the present sensitometric study over

  2. Breeding biology of tree swallows and house wrens in a gradient of gamma radiation

    SciTech Connect

    Zach, R.; Mayoh, K.R.

    1982-12-01

    In a gradient of gamma radiation ranging from 38.7 mC.kg/sup -1/.d/sup -1/ to background levels of 0.05 ..mu..C.kg/sup -1/.d/sup -1/, Tree Swallows (Iridoprocne bicolor) and House Wrens (Troglodytes aedon) avoided nesting in areas of high radiation. Nest boxes selected by swallows and wrens had a mean exposure rate of only 9.3 and 6.6 ..mu..C.kg/sup -1/.d/sup -1/, respectively. Lateral and canopy vegetation indices and nest hole height and direction could not explain the observed pattern of box selection. Of the boxes with low exposure rates, swallows selected those with little vegetation cover, whereas wrens chose boxes with heavy cover. It appears that the birds responded to radiaton levels as low as 100 times background but it is not clear whether they actually detected radiation or simply responded to secondary clues. The number of swallows and wrens fledged per box was unrelated to radiation exposure. The same was true for number of eggs, hatching success, fledging success, incubation time, and nestling time. Breeding success was reduced because of infertile eggs, eggs with dead embryos, cracked eggs, predation, adverse weather, abandonment, and parasites. The logistic model was ideally suited for describing gains in mass in nestling swallows and wrens. Growth of nestlings was not related to radiation exposure as indicated by the growth rate constant, asymptotic mass, and the proportion of variation explained by the logistic model. The data show that birds avoided adverse effects of radiation by judicious box selection. However, there were indications that at higher breeding densities birds may use high-exposure boxes, where breeding success or growth of nestlings may become reduced due to radiation.

  3. Influence of gamma radiation on hindered phenols in LDPE, paraffin oil and paraffin wax

    NASA Astrophysics Data System (ADS)

    Ahmed, Shamshad; Yasin, Tariq; Ghaffar, Abdul

    2003-12-01

    Extraction and high performance liquid chromatography procedures have been developed for the determination of two hindered phenols—Irganox-1010 and Santonox ®, incorporated in low density polyethylene (LDPE), paraffin oil and paraffin wax at varied concentrations. These blends were gamma irradiated from 25 to 400 kGy and the radiation and thermal stability of the antioxidant under the experimental conditions has been determined. Upon increase in radiation dose from 25 to 400 kGy, a gradual diminution in the extractable level of each antioxidant was observed. The fate of both the antioxidants in various matrices has been compared. It has been shown that both the antioxidants can influence the polyethylene network formation and the radical yield in different ways resulting in retardation in the rate of crosslinking, as determined by gel-content analysis.

  4. MEASUREMENT OF THE HIGH GAMMA RADIATION DOSE USING THE MEMS BASED DOSIMETER AND RADIOLISYS EFFECT

    E-print Network

    Boyer, Edmond

    of high and very high doses of ionizing radiation is crucial for the monitoring of the existing Nuclear transducers, humidity sensors and , of course, radiation detectors and dosimeters. On the other hand, we-CEN in Belgium. Figure 1: Gamma radiation dose inside the vessel of the research nuclear reactor in Belgium

  5. Effect of gamma-radiation on cation transport across an artificial membrane

    Microsoft Academic Search

    V. Vijayavergiya; A. Mookerjee

    1989-01-01

    The effect of gamma radiation on cation transport across an artificial membrane has been measured. The membrane of 18C6 or phen in CHCl3 has been gammairradiated, and the radiation effect studied in terms of cation selectivity. The magnitude of transportation is increased under ionizing radiation specificity is changed from potassium to cesium and strontium to barium.

  6. Gamma Ray Telescope Senses High-Energy Radiation

    NSDL National Science Digital Library

    WNET

    2011-11-02

    This video from NASA describes the GLAST satellite, which is equipped with a gamma-ray telescope, and shares some background about the kinds of extreme universal phenomena indicated by the presence of gamma rays.

  7. Evidence for a Solar Influence on Gamma Radiation from Radon

    NASA Astrophysics Data System (ADS)

    Sturrock, P. A.; Steinitz, G.; Fischbach, E.; Javorsek, D.; Jenkins, J.

    2012-12-01

    We have analyzed 29,000 measurements of gamma radiation associated with the decay of radon confined to an airtight vessel at the Geological Survey of Israel (GSI) Laboratory in Jerusalem between January 28 2007 and May 10 2010. These measurements exhibit strong variations in time of year and time of day, which may be due in part to environmental influences. However, time-series analysis reveals a number of strong periodicities, including two at approximately 11.2 year-1 and 12.5 year-1. We consider it significant that these same oscillations have previously been detected in nuclear-decay data acquired at the Brookhaven National Laboratory and at the Physiklisch-Technische Bundesanstalt. We have suggested that these oscillations are due to some form of solar radiation (possibly neutrinos) that has its origin in the deep solar interior. A curious property of the GSI data is that the annual oscillation is much stronger in daytime data than in nighttime data, but the opposite is true for all other oscillations. Time-frequency analysis also yields quite different results from daytime and nighttime data. These procedures have also been applied to data collected from subsurface geological sites in Israel, Tenerife, and Italy, which have a variety of geological and geophysical scenarios, different elevations, and depths below the surface ranging from several meters to 1000 meters. In view of these results, and in view of the fact that there is at present no clear understanding of the behavior of radon in its natural environment, there would appear to be a need for multi-disciplinary research. Investigations that clarify the nature and mechanisms of solar influences may help clarify the nature and mechanisms of geological influences.

  8. Natural gamma-radiation in the Aeolian volcanic arc.

    PubMed

    Chiozzi, P; Pasquale, V; Verdoya, M; Minato, S

    2001-11-01

    Pulse-height distributions of gamma-rays, obtained with a field NaI(Tl) scintillation spectrometer in numerous sites of the Lipari and Vulcano islands (Aeolian volcanic arc, Italy), were measured to determine the U, Th and K concentrations of the bedrock and the relative values of the air absorbed dose rate. U is spatially related to both Th and K and the Th/U ratio is on average 3.1-3.5. The magmatic evolution is reflected by the concentration of the three radioelements, as they are more abundant within the more felsic units of the volcanic series. The higher values of U (15.7-20.0 ppm) coincide with higher Th (48.3-65.9 ppm) and K (4.9-6.1%) concentrations associated with rhyolitic rocks of the third cycle (< 50 ky). The air absorbed dose rate varies from 20 to 470 nGy h(-1). The highest values (> 350 nGy h(-1)) are observed on outcrops of rhyolitic obsidian lava flows. The cosmic-ray contribution is also evaluated to estimate the total background radiation dose rate. PMID:11573810

  9. APPLICATION OF JITTER RADIATION: GAMMA-RAY BURST PROMPT POLARIZATION

    SciTech Connect

    Mao, Jirong [Astrophysical Big Bang Lab, RIKEN, Saitama 351-0198 (Japan); Wang, Jiancheng, E-mail: jirong.mao@riken.jp [Yunnan Observatory, Chinese Academy of Sciences, 650011 Kunming, Yunnan Province (China)

    2013-10-10

    A high degree of polarization of gamma-ray burst (GRB) prompt emission has been confirmed in recent years. In this paper, we apply jitter radiation to study the polarization feature of GRB prompt emission. In our framework, relativistic electrons are accelerated by turbulent acceleration. Random and small-scale magnetic fields are generated by turbulence. We further determine that the polarization property of GRB prompt emission is governed by the configuration of the random and small-scale magnetic fields. A two-dimensional compressed slab, which contains a stochastic magnetic field, is applied in our model. If the jitter condition is satisfied, the electron deflection angle in the magnetic field is very small and the electron trajectory can be treated as a straight line. A high degree of polarization can be achieved when the angle between the line of sight and the slab plane is small. Moreover, micro-emitters with mini-jet structures are considered to be within a bulk GRB jet. The jet 'off-axis' effect is intensely sensitive to the observed polarization degree. We discuss the depolarization effect on GRB prompt emission and afterglow. We also speculate that the rapid variability of GRB prompt polarization may be correlated with the stochastic variability of the turbulent dynamo or the magnetic reconnection of plasmas.

  10. Gamma radiation effect on gas production in anion exchange resins

    NASA Astrophysics Data System (ADS)

    Traboulsi, A.; Labed, V.; Dauvois, V.; Dupuy, N.; Rebufa, C.

    2013-10-01

    Radiation-induced decomposition of Amberlite IRA400 anion exchange resin in hydroxide form by gamma radiolysis has been studied at various doses in different atmospheres (anaerobic, anaerobic with liquid water, and aerobic). The effect of these parameters on the degradation of ion exchange resins is rarely investigated in the literature. We focused on the radiolysis gases produced by resin degradation. When the resin was irradiated under anaerobic conditions with liquid water, the liquid phase over the resin was also analyzed to identify any possible water-soluble products released by degradation of the resin. The main products released are trimethylamine (TMA), molecular hydrogen (H2g) and carbon dioxide (CO2g). TMA and H2g are produced in all the irradiation atmospheres. However, TMA was in gaseous form under anaerobic and aerobic conditions and in aqueous form in presence of liquid water. In the latter conditions, TMAaq was associated with aqueous dimethylamine (DMAaq), monomethylamine (MMAaq) and ammonia (NH). CO2g is formed in the presence of oxygen due to oxidation of organic compounds present in the system, in particular the degradation products such as TMAg.

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

    SciTech Connect

    Baluev, V. V. [All-Russian Research Institute of Experimental Physics, Russian Federal Nuclear Center (Russian Federation); Bogdanova, L. N. [State Scientific Center of the Russian Federation 'Institute of Theoretical and Experimental Physics,' (Russian Federation); Bom, V. R. [Delft University of Technology (Netherlands); Demin, D. L., E-mail: demin@jinr.ru [Joint Institute for Nuclear Research (Russian Federation); Eijk, C. W. E. van [Delft University of Technology (Netherlands); Filchenkov, V. V.; Grafov, N. N. [Joint Institute for Nuclear Research (Russian Federation); Grishechkin, S. K. [All-Russian Research Institute of Experimental Physics, Russian Federal Nuclear Center (Russian Federation); Gritsaj, K. I.; Konin, A. D. [Joint Institute for Nuclear Research (Russian Federation); Mikhailyukov, K. L. [All-Russian Research Institute of Experimental Physics, Russian Federal Nuclear Center (Russian Federation); Rudenko, A. I. [Joint Institute for Nuclear Research (Russian Federation); Vinogradov, Yu. I. [All-Russian Research Institute of Experimental Physics, Russian Federal Nuclear Center (Russian Federation); Volnykh, V. P. [Joint Institute for Nuclear Research (Russian Federation); Yukhimchuk, A. A. [All-Russian Research Institute of Experimental Physics, Russian Federal Nuclear Center (Russian Federation); Yukhimchuk, S. A. [Joint Institute for Nuclear Research (Russian Federation)

    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.

  12. VizieR Online Data Catalog: HEGRA AIROBICC gamma radiation above 15 TeV (Aharonian+, 2002)

    NASA Astrophysics Data System (ADS)

    Aharonian, F.; Akhperjanian, A.; Barrio, J. A.; Bernloehr, K.; Boerst, H.; Bojahr, H.; Bolz, O.; Contreras, J. L.; Cortina, J.; Denninghoff, S.; Fonseca, V.; Gebauer, H. J.; Gonzalez, J.; Goetting, N.; Heinzelmann, G.; Hermann, G.; Heusler, A.; Hofmann, W.; Horns, D.; Jung, I.; Kankanyan, R.; Kestel, M.; Kettler, J.; Kohnle, A.; Konopelko, A.; Kornmeyer, H.; Kranich, D.; Krawczynski, H.; Lampeitl, H.; Lopez, M.; Lorenz, E.; Lucarelli, F.; Magnussen, N.; Mang, O.; Meyer, H.; Mirzoyan, R.; Moralejo, A.; Ona, E.; Padilla, L.; Panter, M.; Plaga, R.; Plyasheshnikov, A.; Prahl, J.; Puehlhofer, G.; Rauterberg, G.; Roehring, A.; Rhode, W.; Rowell, G.; Sahakian, V.; Samorski, M.; Schilling, M.; Schmele, D.; Schroeder, F.; Sevilla, I.; Siems, M.; Stamm, W.; Tluczykont, M.; Voelk, H. J.; Wiedner, C. A.; Wittek, W.

    2002-05-01

    Results of the search for gamma radiation above 15 TeV, using the AIROBICC air shower detector, from a set of 196 candidate point sources taken from different catalogs. For each object, the equatorial coordinates are provided, together with the number of signal events registered by the detector, the estimated background, the statistical significance of the excess (or defect) of events, the average energy threshold of the observation (in TeV), and the flux upper limit (at 90% confidence level) of gamma rays above this threshold. (2 data files).

  13. Virtuality Distributions in application to gamma gamma* to pi^0 Transition Form Factor at Handbag Level

    SciTech Connect

    Radyushkin, Anatoly V. [ODU, JLAB

    2014-07-01

    We outline basics of a new approach to transverse momentum dependence in hard processes. As an illustration, we consider hard exclusive transition process gamma*gamma -> to pi^0 at the handbag level. Our starting point is coordinate representation for matrix elements of operators (in the simplest case, bilocal O(0,z)) describing a hadron with momentum p. Treated as functions of (pz) and z^2, they are parametrized through a virtuality distribution amplitude (VDA) Phi (x, sigma), with x being Fourier-conjugate to (pz) and sigma Laplace-conjugate to z^2. For intervals with z^+=0, we introduce transverse momentum distribution amplitude (TMDA) Psi (x, k_\\perp), and write it in terms of VDA Phi (x, \\sigma). The results of covariant calculations, written in terms of Phi (x sigma) are converted into expressions involving Psi (x, k_\\perp. Starting with scalar toy models, we extend the analysis onto the case of spin-1/2 quarks and QCD. We propose simple models for soft VDAs/TMDAs, and use them for comparison of handbag results with experimental (BaBar and BELLE) data on the pion transition form factor. We also discuss how one can generate high-k_\\perp tails from primordial soft distributions.

  14. Effect of gamma radiation on the inactivation of aflatoxin B1 in food and feed crops

    PubMed Central

    Ghanem, I.; Orfi, M.; Shamma, M.

    2008-01-01

    Samples of food crops (peanut, peeled pistachio, unpeeled pistachio, rice, and corn) and feed (barley, bran, corn) were autoclave-sterilized, and inoculated with 106 of spore suspension of an isolate of Aspergillus flavus fungus known to produce aflatoxin B1 (AFB1) . Following a 10-day period of incubation at 27 C to allow for fungal growth, food and feed samples were irradiated with gamma radiation at the doses 4, 6, and 10 kGy. Results indicated that degradation of AFB1 was positively correlated with the increase in the applied dose of gamma ray for each tested sample. At a dose of 10 kGy percentages of AFB1 degradation reached highest values at 58.6, 68.8, 84.6, 81.1 and 87.8% for peanuts, peeled pistachios, unpeeled pistachios, corn and rice samples, respectively. In feed samples percentages of AFB1 degradation were 45, 66, and 90% in barley, 47, 75, and 86% in bran, and 31, 72, and 84% in corn for the doses of 4, 6, and 10 kGy, respectively. AFB1 degradation in food samples correlated negatively with oil content in irradiated samples. Thus, in peanuts, which contained the highest oil content, percentage of AFB1 degradation at 10 kGy was not more than 56.6%, whereas, the corresponding value in corn, which contained the lowest oil content, reached as high as 80%. The above results indicate the possibility of using gamma radiation as a means of degradation of AFB1 in food and feed crops to levels lower than the maximum allowed levels. PMID:24031308

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

    SciTech Connect

    Yamamoto, Seiichi [Kobe City College of Technology, 8-3, Gakuen-Higashi-machi, Nishi-ku, Kobe, 651-2194 (Japan); Hatazawa, Jun [Osaka University of Graduate School of Medicine, 2-2, Yamadaoka, Suita-shi, Osaka, 565-0871 (Japan)

    2011-11-15

    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{sub 2}SiO{sub 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.

  16. 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. PMID:22128972

  17. 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.

  18. 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.

  19. Flash polymerization of silicone oils using gamma radiation for conserving waterlogged wood 

    E-print Network

    Gidden, Richmond Paul

    1996-01-01

    the SFD-I /SFD-5 mix. These bulked samples were exposed to gamma radiation emitted from a nuclear research reactor and received gamma doses ranging from 30 Gy to 228 Gy with dose rates ranging from 0.6 Gy/min to 5.1 Gy/min. Following irradiation, thin...

  20. Branching fractions and CP-violating asymmetries in radiative B decays to eta K gamma

    E-print Network

    Zhao, M.

    We present measurements of the CP-violation parameters S and C for the radiative decay B0-->etaKS0gamma; for B-->etaKgamma we also measure the branching fractions and for B+-->etaK+gamma the time-integrated charge asymmetry ...

  1. Ab initio calculation of the $np \\to d \\gamma$ radiative capture process

    E-print Network

    Beane, Silas R; Detmold, William; Orginos, Kostas; Parreño, Assumpta; Savage, Martin J; Tiburzi, Brian C

    2015-01-01

    Lattice QCD calculations of two-nucleon systems are used to isolate the short-distance two-body electromagnetic contributions to the radiative capture process $np \\to d\\gamma$, and the photo-disintegration processes $\\gamma^{(\\ast)} d \\to np$. In nuclear potential models, such contributions are described by phenomenological meson-exchange currents, while in the present work, they are determined directly from the quark and gluon interactions of QCD. Calculations of neutron-proton energy levels in multiple background magnetic fields are performed at two values of the quark masses, corresponding to pion masses of $m_\\pi \\sim 450$ and 806 MeV, and are combined with pionless nuclear effective field theory to determine these low-energy inelastic processes. Extrapolating to the physical pion mass, a cross section of $\\sigma^{lqcd}(np\\to d\\gamma)=332.4({\\tiny \\begin{array}{l}+5.4 \\\\ - 4.7\\end{array}})\\ mb$ is obtained at an incident neutron speed of $v=2,200\\ m/s$, consistent with the experimental value of $\\sigma^{e...

  2. Aflatoxins and ochratoxin a reduction in black and white pepper by gamma radiation

    NASA Astrophysics Data System (ADS)

    Jalili, M.; Jinap, S.; Noranizan, M. A.

    2012-11-01

    Irradiation is an important means of decontamination of food commodities, especially spices. The aim of the current study was to investigate the efficacy of gamma radiation (60Co) for decontaminating ochratoxin A (OTA) and aflatoxins B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) residues in artificially contaminated black and white pepper samples. The moisture content of the pepper samples was set at 12% or 18%, and the applied gamma dose ranged from 5 to 30 kGy. Mycotoxin levels were determined by high-performance liquid chromatography (HPLC) after immunoaffinity column (IAC) chromatography. Both the gamma irradiation dose and moisture content showed significant effects (P<0.05) on mycotoxin reduction. The maximum toxin reductions, found at 18% moisture content and 30 kGy, were 55.2%, 50.6%, 39.2%, 47.7% and 42.9% for OTA, AFB1, AFB2, AFG1 and AFG2, respectively.

  3. Gamma Radiation Sensing Using ZnO and SnO2 Thick Film Interdigitated Capacitors

    Microsoft Academic Search

    K. Arshak; O. Korostynska; E. Jafer; A. Arshak; D. Morris; E. Gill

    2006-01-01

    A novel cost-effective real-time gamma radiation monitoring system based on metal oxide thick films was designed and tested. The changes in capacitances of ZnO and SnO2 thick film capacitors with interdigitated electrodes were monitored in real time under the influence of gamma radiation using miniaturized, low power, bi-directional wireless communication system. The capacitive interface circuitry was based on a Delta-sigma

  4. Airborne time-series measurement of soil moisture using terrestrial gamma radiation

    NASA Technical Reports Server (NTRS)

    Carroll, Thomas R.; Lipinski, Daniel M.; Peck, Eugene L.

    1988-01-01

    Terrestrial gamma radiation data and independent ground-based core soil moisture data are analyzed. They reveal the possibility of using natural terrestrial gamma radiation collected from a low-flying aircraft to make reliable real-time soil moisture measurements for the upper 20 cm of soil. The airborne data were compared to the crude ground-based soil moisture data set collected at the core sites.

  5. Cytoskeletal and functional changes in bioreactor assembled thyroid tissue organoids exposed to gamma radiation

    NASA Technical Reports Server (NTRS)

    Green, Lora M.; Patel, Zarana; Murray, Deborah K.; Rightnar, Steven; Burell, Cheryl G.; Gridley, Daila S.; Nelson, Gregory A.

    2002-01-01

    Fischer rat thyroid cells were grown under low-shear stress in a bioreactor to a stage of organization composed of integrated follicles resembling small thyroid glands prior to exposure to 3 Gray-gamma radiation. Bioreactor tissues and controls (both irradiated and non-irradiated) were harvested at 24, 48, 96 and 144 hours post-exposure. Tissue samples were fixed and fluorescently labeled for actin and microtubules. Tissues were assessed for changes in cytoskeletal components induced by radiation and quantified by laser scanning cytometry. ELISA's were used to quantify transforming growth factor-beta and thyroxin released from cells to the culture supernatant. Tissue architecture was disrupted by exposure to radiation with the structural organization of actin and loss of follicular content the most obviously affected. With time post-irradiation the actin appeared disordered and the levels of fluorescence associated with filamentous-actin and microtubules cycled in the tissue analogs, but not in the flask-grown cultures. Active transforming growth factor-beta was higher in supernatants from the irradiated bioreactor tissue. Thyroxin release paralleled cell survival in the bioreactors and control cultures. Thus, the engineered tissue responses to radiation differed from those of conventional tissue culture making it a potentially better mimic of the in vivo situation.

  6. Potential for radiation damage to carbon steel storage tanks for high level radioactive waste

    SciTech Connect

    Caskey, G.R. Jr.; Sindelar, R.L.; Thomas, J.K.

    1993-07-30

    A low intensity radiation field is generated by the high level waste that is stored within carbon steel lined tanks at the Savannah River Site (SRS). The highest level of radiation damage to the tank walls from gamma and spontaneous neutron emissions is estimated to be less than 1.0E-6 displacements per atom (DPA) for a 100 year exposure to fresh, ``high heat`` SRS waste assuming continuous replenishment of the radionuclides. This damage level is below the limit for measurable radiation damage to the mechanical properties of carbon steel. Structural assessment of tanks for storage of high level waste may be based on nominal or code values of the mechanical properties of the steels from which the tanks were constructed.

  7. The gamma ray content of ultrahigh energy cosmic radiation

    SciTech Connect

    Kolodziejczak, J.J.

    1990-01-01

    Data from the Utah-Michigan (UM) extensive air shower (EAS) array at Dugway, Utah are examined for evidence of a gamma ray component in the UHE cosmic rays. The UM array consist of a 3 {times} 10{sup 4} sq m surface array with 40 sq m of charged particle detectors, and a 1200 sq m buried array for detecting muons. Data from the large muon array are used to search for a gamma ray signature, since gamma rays are expected to produce far fewer muons in EAS than hadronic cosmic ray primaries. When no evidence for gamma rays is found, limits are set based on expected gamma ray behavior. For a photon energy threshold of 200 TeV, results include: a limit on the omnidirectional gamma ray fraction of cosmic rays at 0.2 pct; a limit on the galactic gamma ray fraction of cosmic rays at 7 {times} 10{sup {minus}5}; no strong evidence for enduring gamma ray point sources at fluxes approx. = 4 {times} 10{sup {minus}14}/sq cm/s; and no strong evidence for bursts on a one day time scale at a flux sensitivity {approx} 2 {times} 10{sup {minus}12}/sq cm/s. These limits and measurements are based on muon poor data. While no strong signal of UHE gamma rays is found, future application to the large Chicago Air Shower Array-Michigan Array (CASA-MIA) is possible.

  8. Constraining |V(td)|/|V(ts)| Using Radiative Penguin B -> V(K*/rho/omega)gamma Decays

    SciTech Connect

    Tan, Ping; /Wisconsin U., Madison

    2006-03-08

    Exclusive radiative penguin B decays, B {yields} (K*{sup 0}/K*{sup +}) and B {yields} ({rho}/{omega}){gamma}, are flavor-changing neutral-current (FCNC) processes. Studies of these decays are of special interest in testing Standard Model (SM) predictions and searching for other beyond-the-SM FCNC interactions. Using 89 x 10{sup 6} B{bar B} pairs from BABAR, we measure the branching fraction ({Beta}), CP-asymmetry ({Alpha}), and isospin asymmetry ({Delta}{sub 0-}) of B {yields} (K*{sup 0}/K*{sup +}){gamma} as follows: {Beta}(B{sup 0} {yields} K*{sup 0}{gamma}) = 3.92 {+-} 0.20(stat.) {+-} 0.24(syst.); {Beta}(B{sup +} {yields} K*{sup +}{gamma}) = 3.87 {+-} 0.28(stat.) {+-} 0.26(syst.); {Alpha}(B {yields} K*{gamma}) = -0.013 {+-} 0.36(stat.) {+-} 0.10(syst.); {Delta}{sub 0-}(B {yields} K*{gamma}) = 0.050 {+-} 0.045(stat.) {+-} 0.028(syst.) {+-} 0.024(R{sup +/0}). The 90% confidence intervals for the CP-asymmetry and the isospin-asymmetry in the B {yields} K*{gamma} decay are given as: -0.074 < {Alpha}(B {yields} K*{gamma}) < 0.049, -0.046 < {Delta}{sub 0-} (B {yields} K*{gamma}) < 0.146. We also search for B {yields} ({rho}/{omega}){gamma} decays using 211 x 10{sup 6} B{bar B} pairs from BABAR. No evidence for these decays is found. We set the upper limits at 90% confidence level for these decays: {Beta}(B{sup 0} {yields} {rho}{sup 0}{gamma}) < 0.4 x 10{sup -6}; {Beta}(B{sup +}{yields} {rho}{sup =}{gamma}) < 1.8 x 10{sup -6}; {Beta}(B{sup 0} {yields} {omega}{gamma}) < 1.0 x 10{sup -6}; {bar {Beta}}(B {yields} ({rho}/{omega}){gamma}) < 1.2 x 10{sup -6}. These results are in good agreement with the SM predictions. The branching fractions of these decays are then used to constrain the ratio |V{sub td}|/|V{sub ts}|.

  9. Protection effects of condensed bromoacenaphthylene on radiation deterioration of ethylene-propylene-diene rubber. [Gamma radiation

    SciTech Connect

    Morita, Y.; Hagiwara, M.; Kasai, N.

    1982-09-01

    As a continuation of a series of the studies on the flame and ..gamma..-radiation resistant modification of ethylene-propylene-diene rubber (EPDM), condensed bromoacenaphthylene (con-BACN) as a newly developed flame retardant was synthesized and its effects on the radiation resistance of EPDM were investigated. The radiation resistance evaluated by measuring tensile properties of irradiated sheets of 2 mm thick was found improved greatly by adding con-BACN together with ordinary rubber ingredients but decreased by decabromodiphenylether (DBDPE) that has bromins in aromatic rings as con-BACN. When EPDM sheets of 1 mm thick were irradiated in oxygen at a dose rate of 1 X 10/sup 5/ rad/h, the weight swelling ratio increased with increasing dose, indicating that oxidative main chain scission is predominant under the irradiation conditions. On the other hand, crosslinking was shown to be predominant in nitrogen. From the results of the swelling experiments with different additives, it was concluded that DBDPE accelerates both the main chain scission in oxygen and the crosslinking in nitrogen. In contrast to this, con-BACN reduced the chain scission in oxygen. This observation was accounted by the assumption that the influence of the oxidative chain scission is partly compensated by the concurrent crosslinking which takes place through additions of con-BACN to substrate polymers even in the presence of oxygen.

  10. Gamma radiation induces growth retardation, impaired egg production, and oxidative stress in the marine copepod Paracyclopina nana.

    PubMed

    Won, Eun-Ji; Lee, Jae-Seong

    2014-05-01

    Accidental nuclear radioisotope release into the ocean from nuclear power plants is of concern due to ecological and health risks. In this study, we used the marine copepod Paracyclopina nana to examine the effects of radioisotopes on marine organisms upon gamma radiation, and to measure the effects on growth and fecundity, which affect population and community structure. Upon gamma radiation, mortality (LD50 - 96 h=172 Gy) in P. nana was significantly increased in a dose-dependent manner in ovigerous P. nana females. For developmental impairment of gamma-irradiated nauplii, we observed growth retardation; in over 30 Gy-irradiated groups, offspring did not grow to adults. Particularly, over 50 Gy-irradiated ovigerous P. nana females did not have normal bilateral egg sacs, and their offspring did not develop normally to adulthood. Additionally, at over 30 Gy, we found dose-dependent increases in oxidative levels with elevated antioxidant enzyme activities and DNA repair activities. These findings indicate that gamma radiation can induce oxidative stress and DNA damage with growth retardation and impaired reproduction. PMID:24632311

  11. Galactic Center Gamma Ray Excess in a Radiative Neutrino Mass Model

    E-print Network

    Debasish Borah; Arnab Dasgupta

    2014-12-08

    The Fermi gamma ray space telescope data have pointed towards an excess of gamma rays with a peak around $1-3$ GeV in the region surrounding the galactic center. This anomalous excess can be described well by a dark matter candidate having mass in the range $31-40$ GeV annihilating into $b\\bar{b}$ pairs with a cross section of $ \\simeq (1.4-2.0) \\times 10^{-26} \\; \\text{cm}^3/\\text{s}$. In this work we explore the possibility of having such a dark matter candidate within the framework of a radiative neutrino mass model. The model is a simple extension of the standard model by an additional $U(1)_X$ gauge symmetry where the standard model neutrino masses arise both at tree level as well as radiatively by the anomaly free addition of one singlet fermion $N_R$ and two triplet fermions $\\Sigma_{1R}, \\Sigma_{2R}$ with suitable Higgs scalars. The spontaneous gauge symmetry breaking is achieved in such a way which results in a residual $Z_2$ symmetry and hence providing a stable cold dark matter candidate. We show that the singlet fermionic dark matter candidate in our model can give rise to the galactic center gamma ray excess. The parameter space which simultaneously satisfy the constraints on relic density, direct detection scattering as well as collider bounds essentially corresponds to an s-wave resonance where the gauge boson mass $m_X$ is approximately twice that of dark matter mass $m_{\\chi}$. We also discuss the compatibility of such a light fermion singlet dark matter with light neutrino mass.

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

    SciTech Connect

    Al-Houty, L.; Abou-Leila, H.; El-Kameesy, S. (Qatar Univ., Doha (Qatar))

    1987-01-01

    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.

  13. Simulation of the gamma radiation field in lumpy environments

    Microsoft Academic Search

    B. J. Brennan; H. P. Schwarcz; W. J. Rink

    1997-01-01

    Many of the environments used for ESR and luminescence dating are inhomogeneous over the distances up to 0.3 m which contribute to gamma doses, and the consequent variability in gamma dose usually cannot be ascertained on a sample by sample basis. In this paper we examine the characteristics of such “lumpy” environments by simulation. Random environments were generated in which

  14. Effect of high doses of gamma radiation on the functional characteristics of amniotic membrane

    NASA Astrophysics Data System (ADS)

    Singh, Rita; Purohit, Sumita; Chacharkar, M. P.

    2007-06-01

    The effect of different doses of gamma radiation viz. 25, 36 and 50 kGy on the chemical and functional characteristics of the amniotic membrane was studied. The change in the chemical structure of amniotic membranes at high doses of gamma irradiation was evaluated by means of Infrared (IR) Spectroscopy. The degradation of amnion on irradiation with gamma rays could produce a relative variation in IR absorption troughs. This kind of variation was absent in the samples irradiated to doses of 25, 36 and 50 kGy indicating no qualitative change in the material property of amnion. No significant differences in the water absorption capacity and water vapour transmission rate of amniotic membranes irradiated to different doses were observed. Impermeability of the amniotic membranes to different microorganisms was also not affected at high doses of gamma radiation. Gamma irradiation at doses of 25-50 kGy did not evoke undesirable changes in the functional properties of the amniotic membrane.

  15. RADIATIVE PROCESSES (TAU ---> MU GAMMA, MU ---> E GAMMA AND MUON G-2) AS PROBES OF ESSM / SO(10)

    SciTech Connect

    Pati, Jogesh C

    2002-08-08

    The Extended Supersymmetric Standard Model (ESSM), motivated on several grounds, introduces two vectorlike families (16 + 16) of SO(10) with masses of order one TeV. It is noted that the successful predictions of prior work on fermion masses and mixings, based on MSSM embedded in SO(10), can be retained rather simply within the ESSM extension. These include an understanding of the smallness of V{sub cb} {approx} 0.04 and the largeness of {nu}{sub {mu}}-{nu}{sub {tau}} oscillation angle, sin{sup 2} 2{theta}{sub {nu}{sub {mu}}{nu}{sub {tau}}}{sup OSC} {approx} 1. We analyze the new contributions arising through the exchange of the vectorlike families of ESSM to radiative processes including {tau} {yields} {mu}{gamma}, {mu} {yields} e{gamma}, b {yields} s{gamma}, EDM of the muon and the muon (g-2). We show that ESSM makes significant contributions especially to the decays {tau} {yields} {mu}{gamma} and {mu} {yields} e{gamma} and simultaneously to muon (g-2). For a large and plausible range of relevant parameters, we obtain: a{sub {mu}}{sup ESSM} {approx} +(10-40) x 10{sup -10}, with a correlated prediction that {tau} {yields} {mu}{gamma} should be discovered with an improvement in its current limit by a factor of 3-20. The implications for {mu} {yields} e{gamma} are very similar. The muon EDM is within reach of the next generation experiments. Thus, ESSM with heavy leptons being lighter than about 700 GeV (say) can be probed effectively by radiative processes before a direct search for these vectorlike leptons and quarks is feasible at the LHC.

  16. Gamma radiation shielding and health physics characteristics of diaspore-flyash concretes.

    PubMed

    Singh, Kanwaldeep; Singh, Sukhpal; Singh, S P; Mudahar, Gurmel S; Dhaliwal, A S

    2015-06-01

    Different gamma radiation interaction parameters has been measured experimentally for the prepared diaspore-flyash concretes at 59.54, 662, 1173 and 1332?keV using narrow-beam transmission geometry and results are found to be in good agreement with theoretical values computed with a computer programme, WinXCom. The radiation exposure rate and absorbed dose rate for the gamma radiation with and without shielding of diaspore-flyash concretes have been determined using linear attenuation results. The results show that on average, there is reduction of 95%, 53% and 40% in dose rate for gamma sources (241)Am, (137)Cs and (60)Co, respectively with diaspore-flyash concretes as shielding material. Other health physics parameters namely equivalent dose, effective dose, gamma flux and energy fluence rate have also been determined. PMID:25946622

  17. Isodose mapping of terrestrial gamma radiation dose rate of Selangor state, Kuala Lumpur and Putrajaya, Malaysia.

    PubMed

    Sanusi, M S M; Ramli, A T; Gabdo, H T; Garba, N N; Heryanshah, A; Wagiran, H; Said, M N

    2014-09-01

    A terrestrial gamma radiation survey for the state of Selangor, Kuala Lumpur and Putrajaya was conducted to obtain baseline data for environmental radiological health practices. Based on soil type, geological background and information from airborne survey maps, 95 survey points statistically representing the study area were determined. The measured doses varied according to geological background and soil types. They ranged from 17 nGy h(-1) to 500 nGy h(-1). The mean terrestrial gamma dose rate in air above the ground was 182 ± 81 nGy h(-1). This is two times higher than the average dose rate of terrestrial gamma radiation in Malaysia which is 92 nGy h(-1) (UNSCEAR 2000). An isodose map was produced to represent exposure rate from natural sources of terrestrial gamma radiation. PMID:24787672

  18. Effects of interferon-gamma and tumor necrosis factor-alpha on macrophage enzyme levels

    NASA Technical Reports Server (NTRS)

    Pierangeli, Silvia S.; Sonnenfeld, Gerald

    1989-01-01

    Murine peritoneal macrophages were treated with interferon-gamma (IFN-gamma) or tumor necrosis factor-alpha (TNF). Measurements of changes in acid phosphatase and beta-glucuronidase levels were made as an indication of activation by cytokine treatment. IFN-gamma or TNF-gamma treatment resulted in a significant increase in the activities of both enzymes measured in the cell lysates. This increase was observable after 6 h of incubation, but reached its maximum level after 24 h of incubation. The effect of the treatment of the cell with both cytokines together was additive. No synergistic effect of addition of both cytokines on the enzyme levels was observed.

  19. Reliability studies on Si PIN photodiodes under Co-60 gamma radiation

    SciTech Connect

    Prabhakara Rao, Y. P. [Integrated Circuits Division, Bharat Electronics Limited, Bangalore, Karnataka-560013 (India) and Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore, Karnataka-570006 (India); Praveen, K. C.; Gnana Prakash, A. P. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore, Karnataka-570006 (India); Rani, Y. Rejeena [Integrated Circuits Division, Bharat Electronics Limited, Bangalore, Karnataka-560013 (India)

    2013-02-05

    Silicon PIN photodiodes were fabricated with 250 nm SiO{sub 2} antireflective coating (ARC). The changes in the electrical characteristics, capacitance-voltage characteristics and spectral response after gamma irradiation are systematically studied to estimate the radiation tolerance up to 10 Mrad. The different characteristics studied in this investigation demonstrate that Si PIN photodiodes are suitable for high radiation environment.

  20. Dosimetric criteria of canine mortality following total-body nonuniform irradiation. [Gamma radiation, dogs

    Microsoft Academic Search

    V. L. Gozenbuk; I. B. Keirim-Markus

    1977-01-01

    Results of previous experiments involving nonuniform exposure of dogs to gamma radiation were used for analysis of dosimetric criteria. The equivalent dose characterizes the probability of survival after sustaining the bone marrow form of radiation lesion. In the equivalent dose formula, the function P(D) is hemopoietic activity as a function of dosage. With doses up to 1200 rad, involvement of

  1. Radiation-Induced Carcinogenesis: Mechanistically Based Differences between Gamma-Rays and Neutrons, and

    E-print Network

    Brenner, David Jonathan

    Radiation-Induced Carcinogenesis: Mechanistically Based Differences between Gamma-Rays and Neutrons effect). Densely ionizing radiation (e.g. neutrons) often produces downwardly curving dose responses exposed to high or low dose rates of c-rays and neutrons, either with or without pre

  2. Increase of RhoB in {gamma}-radiation-induced apoptosis is regulated by c-Jun N-terminal kinase in Jurkat T cells

    SciTech Connect

    Kim, Chun-Ho [Laboratory of Cytogenetics and Tissue Regeneration, KIRAMS, Seoul 139-706 (Korea, Republic of)] [Laboratory of Cytogenetics and Tissue Regeneration, KIRAMS, Seoul 139-706 (Korea, Republic of); Won, Misun; Choi, Chung-Hae; Ahn, Jiwon; Kim, Bo-Kyung [Genome Research Center, KRIBB, Daejeon 305-806 (Korea, Republic of)] [Genome Research Center, KRIBB, Daejeon 305-806 (Korea, Republic of); Song, Kyung-Bin [Department of Food Science and Technology, Chungnam National University, Daejeon 305-764 (Korea, Republic of)] [Department of Food Science and Technology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Kang, Chang-Mo, E-mail: kangcm@kcch.re.kr [Laboratory of Cytogenetics and Tissue Regeneration, KIRAMS, Seoul 139-706 (Korea, Republic of)] [Laboratory of Cytogenetics and Tissue Regeneration, KIRAMS, Seoul 139-706 (Korea, Republic of); Chung, Kyung-Sook, E-mail: kschung@kribb.re.kr [Genome Research Center, KRIBB, Daejeon 305-806 (Korea, Republic of)] [Genome Research Center, KRIBB, Daejeon 305-806 (Korea, Republic of)

    2010-01-08

    The Ras-related small GTP-binding protein RhoB is known to be a pro-apoptotic protein and immediate-early inducible by genotoxic stresses. In addition, JNK activation is known to function in {gamma}-radiation-induced apoptosis. However, it is unclear how JNK activation and {gamma}-radiation-dependent RhoB induction are related. Here we verified the relationship between JNK activation and RhoB induction. RhoB induction by {gamma}-radiation occurred at the transcriptional level and transcriptional activation of RhoB was concomitant with an increase in RhoB protein. {gamma}-Radiation-induced RhoB expression was markedly attenuated by pretreatment with a JNK-specific inhibitor, SP600125, but not by a p38 MAPK inhibitor, SB203580. Inhibition of JNK caused a decrease in early apoptotic cell death that correlated with RhoB expression. However, PI3K inhibition had no significant effects, indicating that the AKT survival pathway was not involved. The siRNA knockdown of JNK resulted in a decrease in RhoB expression and the siRNA knockdown of RhoB restored cell growth even in the {gamma}-irradiated cells. These results suggest that RhoB regulation involves the JNK pathway and contributes to the early apoptotic response of Jurkat T cells to {gamma}-radiation.

  3. Terrestrial gamma radiation dose study to determine the baseline for environmental radiological health practices in Melaka state, Malaysia.

    PubMed

    Ramli, Ahmad Termizi; Sahrone, Sallehudin; Wagiran, Husin

    2005-12-01

    Environmental terrestrial gamma radiation dose rates were measured throughout Melaka, Malaysia, over a period of two years, with the objective of establishing baseline data on the background radiation level. Results obtained are shown in tabular, graphic and cartographic form. The values of terrestrial gamma radiation dose rate vary significantly over different soil types and for different underlying geological characteristics present in the study area. The values ranged from 54 +/- 5 to 378 +/- 38 nGy h(-1). The highest terrestrial gamma dose rates were measured over soil types of granitic origin and in areas with underlying geological characteristics of an acid intrusive (undifferentiated) type. An isodose map of terrestrial gamma dose rate in Melaka was drawn by using the GIS application 'Arc View'. This was based on data collected using a NaI(Tl) scintillation detector survey meter. The measurements were taken at 542 locations. Three small 'hot spots' were found where the dose rates were more than 350 nGy h(-1). The mean dose rates in the main population areas in the mukims (parishes) of Bukit Katil, Sungai Udang, Batu Berendam, Bukit Baru and Bandar Melaka were 154 +/- 15, 161 +/- 16, 160 +/- 16, 175 +/- 18 and 176 +/- 18 nGy h(-1), respectively. The population-weighted mean dose rate throughout Melaka state is 172 +/- 17 nGy h(-1). This is lower than the geographical mean dose rate of 183 +/- 54 nGy h(-1). The lower value arises from the fact that most of the population lives in the central area of the state where the lithology is dominated by sedimentary rocks consisting of shale, mudstone, phyllite, slate, hornfels, sandstone and schist of Devonian origin which have lower associated dose rates. The mean annual effective dose to the population from outdoor terrestrial gamma radiation was estimated to be 0.21 mSv. This value is higher than the world average of 0.07 mSv. PMID:16340071

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

    SciTech Connect

    Hamdalla, Taymour A. [Faculty of Science, Alexandria University, Alexandria (Egypt); Faculty of Science, Tabuk University, Tabuk (Saudi Arabia)

    2012-09-06

    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.

  5. Development of a low-level background gamma-ray spectrometer by KRISS.

    PubMed

    Lee, K B; Park, Tae Soon; Lee, Jong Man; Oh, Phil-Je; Lee, Sang-Han

    2008-01-01

    A new low-level background and high-efficiency gamma-ray spectrometric system, to be used mainly for the activity certification of natural-matrix certified reference materials (CRMs) and environmental reference materials (RMs) that has been developed on the grounds of the Korea Research Institute of Standards and Science (KRISS). The spectrometer consists of a low-background high-purity germanium detector with a relative efficiency of 120% and various shielding devices to reduce radiation background. The cabinet-shaped device made of 10ton of shielding materials encloses the germanium detector for protection against background from natural radioactivity and neutrons. Three plates of 50-mm-thick plastic scintillation detectors on top of the passive shielding cabinet suppress cosmogenic background by detecting high-energetic cosmic muons bombarding the germanium detector. The measured background rate of the spectrometer for the energy range 50-3000keV was 1.72s(-1). PMID:18403211

  6. Low Level Gamma Spectroscopy Measurements of Radium and Cesium in Lucerne (Medicago Sativa)

    NASA Astrophysics Data System (ADS)

    Fokapi?, S.; Bikit, I.; Mr?a, D.; Veskovi?, M.; Slivka, J.; Mihaljev, Ž.; ?upi?, Ž.

    2007-04-01

    Nineteen years after Chernobyl nuclear accident, activity concentration of 137Cs still could be detected in food and soil samples in Central and Eastern Europe. In this paper radiation levels of radium and cesium in Lucerne will be presented. It is a perennial plant with a deep root system and it is widely grown throughout the world as forage for cattle. The samples of Lucerne were taken from twelve different locations in Vojvodina in the summer period July-September 2004. The samples were specially dried on the air and after that ground, powdered and mineralized by method of dry burning on the temperature of 450°C. Gamma spectrometry measurements of the ash were performed by means of actively shielded germanium detector with maximal background reduction. For cesium 137Cs 10 mBq/kg order of magnitude detection limits were achieved.

  7. Low Level Gamma Spectroscopy Measurements of Radium and Cesium in Lucerne (Medicago Sativa)

    SciTech Connect

    Fokapic, S.; Bikit, I.; Mrda, D.; Veskovic, M.; Slivka, J. [Department of Physics, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovica 4, 21 000 Novi Sad (Serbia); Mihaljev, Z. [Scientific Veterinary Institute, Rumenacki put 20, 21 000 Novi Sad (Serbia); Cupic, Z. [Research Institute for Reproduction, A.I. and Embryo Transfer Temerin, 21235 Temerin, Industrijska zona bb. (Serbia)

    2007-04-23

    Nineteen years after Chernobyl nuclear accident, activity concentration of 137Cs still could be detected in food and soil samples in Central and Eastern Europe. In this paper radiation levels of radium and cesium in Lucerne will be presented. It is a perennial plant with a deep root system and it is widely grown throughout the world as forage for cattle. The samples of Lucerne were taken from twelve different locations in Vojvodina in the summer period July-September 2004. The samples were specially dried on the air and after that ground, powdered and mineralized by method of dry burning on the temperature of 450 deg. C. Gamma spectrometry measurements of the ash were performed by means of actively shielded germanium detector with maximal background reduction. For cesium 137Cs 10 mBq/kg order of magnitude detection limits were achieved.

  8. High Levels of Natural Radiation: Radiation Doses and Health Effects

    Microsoft Academic Search

    1998-01-01

    Limits on exposure to artificial radiation have been pushed down over the past few decades, while at the same time we have become more aware of the potential for high doses from natural sources. If these two trends were graphed at the same scale they would have crossed years ago, leaving us now with significant numbers of people receiving natural

  9. Study of bulk damage in high resistivity silicon detectors irradiated by high dose of {sup 60}Co {gamma}-radiation

    SciTech Connect

    Li, Z.; Li, C.J.

    1996-04-01

    High dose (> 200 Mrad) {gamma}-radiation induced displacement damage (or bulk damage) in high resistivity (6--10 k{Omega}-cm) silicon detectors has been studied. It has been found that detector bulk leakage current increases with {gamma} dose at a rate of 3.3 {times} 10{sup {minus}7} A/cm{sup 3}/Mrad. This introduction rate of bulk leakage current makes the introduction of generation centers by 210 Mrad of {gamma}-radiation comparable to that by 1 {times} 10{sup 12} n/cm{sup 2} of neutron radiation. Significant carrier removal (or donor removal), about 100%, was found in detectors irradiated to 215 Mrad. Space charge sign inversion (SCSI) (or type inversion) was observed in detectors irradiated to {ge} 215 Mrad using transient current technique (TCT). As many as seven deep levels have been observed by current deep level transient spectroscopy (I-DLTS). There was little or no annealing (or reverse annealing) for detectors irradiated to 215 Mrad. Some annealing for detectors irradiated to 500 Mrad have been observed.

  10. TeV gamma rays from the blazar H 1426+428 and the diffuse extragalactic background radiation

    NASA Astrophysics Data System (ADS)

    Aharonian, F.; Akhperjanian, A.; Barrio, J.; Beilicke, M.; Bernlöhr, K.; Börst, H.; Bojahr, H.; Bolz, O.; Contreras, J.; Cornils, R.; Cortina, J.; Denninghoff, S.; Fonseca, V.; Girma, M.; Gonzalez, J.; Götting, N.; Heinzelmann, G.; Hermann, G.; Heusler, A.; Hofmann, W.; Horns, D.; Jung, I.; Kankanyan, R.; Kestel, M.; Kettler, J.; Kohnle, A.; Konopelko, A.; Kornmeyer, H.; Kranich, D.; Krawczynski, H.; Lampeitl, H.; Lopez, M.; Lorenz, E.; Lucarelli, F.; Magnussen, N.; Mang, O.; Meyer, H.; Mirzoyan, R.; Moralejo, A.; Ona, E.; Padilla, L.; Panter, M.; Plaga, R.; Plyasheshnikov, A.; Pühlhofer, G.; Rauterberg, G.; Röhring, A.; Rhode, W.; Robrade, J.; Rowell, G.; Sahakian, V.; Samorski, M.; Schilling, M.; Schröder, F.; Sevilla, I.; Siems, M.; Stamm, W.; Tluczykont, M.; Völk, H. J.; Wiedner, C. A.; Wittek, W.

    2002-03-01

    The detection of TeV gamma -rays from the blazar H 1426+428 at an integral flux level of (4 +/- 2stat +/- 1syst) x 10-12 erg cm-2 s-1 above 1 TeV with the HEGRA imaging atmospheric Cherenkov telescope system is reported. H 1426+428 is located at a redshift of z = 0.129, which makes it the most distant source detected in TeV gamma -rays so far. The TeV radiation is expected to be strongly absorbed by the diffuse extragalactic background radiation (DEBRA). The observed energy spectrum of TeV photons is in good agreement with an intrinsic power law spectrum of the source ~ E-1.9 corrected for DEBRA absorption. Statistical errors as well as uncertainties about the intrinsic source spectrum, however, do not permit strong statements about the density of the DEBRA infrared photon field.

  11. Radiation chemistry of salt-mine brines and hydrates. [Gamma radiation

    SciTech Connect

    Jenks, G.H.; Walton, J.R.; Bronstein, H.R.; Baes, C.F. Jr.

    1981-07-01

    Certain aspects of the radiation chemistry of NaCl-saturated MgCl/sub 2/ solutions and MgCl/sub 2/ hydrates at temperatures in the range of 30 to 180/sup 0/C were investigated through experiments. A principal objective was to establish the values for the yields of H/sub 2/ (G(H/sub 2/)) and accompanying oxidants in the gamma-ray radiolysis of concentrated brines that might occur in waste repositories in salt. We concluded that G(H/sub 2/) from gamma-irradiated brine solution into a simultaneously irradiated, deaerated atmosphere above the solution is between 0.48 and 0.49 over most of the range 30 to 143/sup 0/C. The yield is probably somewhat lower at the lower end of this range, averaging 0.44 at 30 to 45/sup 0/C. Changes in the relative amounts of MgCl/sub 2/ and NaCl in the NaCl-saturated solutions have negligible effects on the yield. The yield of O/sub 2/ into the same atmosphere averages 0.13, independent of the temperature and brine composition, showing that only about 50% of the radiolytic oxidant that was formed along with the H/sub 2/ was present as O/sub 2/. We did not identify the species that compose the remainder of the oxidant. We concluded that the yield of H/sub 2/ from a gamma-irradiated brine solution into a simultaneously irradiated atmosphere containing 5 to 8% air in He may be greater than the yield in deaerated systems by amounts ranging from 0% for temperatures of 73 to 85/sup 0/C, to about 30 and 40% for temperatures in the ranges 100 to 143/sup 0/C and 30 to 45/sup 0/C, respectively. We did not establish the mechanism whereby the air affected the yields of H/sub 2/ and O/sub 2/. The values found in this work for G(H/sub 2/) in deaerated systems are in approximate agreement with the value of 0.44 for the gamma-irradiation yield of H/sub 2/ in pure H/sub 2/O at room temperature. They are also in agreement with the values predicted by extrapolation from the findings of previous researchers for the value for G(H/sub 2/) in 2 M NaCl solutions at room temperature.

  12. Mortality of the harvester ant (Pogonomyrmex owyheei) after exposure to /sup 137/Cs gamma radiation

    SciTech Connect

    Gano, K.A.

    1981-01-01

    Harvester ants, Pogonomyrmex owyheei Cole, irradiated with 3.5 kR to 268 kR of /sup 137/Cs gamma radiation, were maintained at simulated summer (27/sup 0/C) and winter (7/sup 0/C) temperature regimes. After thirty days, the cool series was warmed to 27/sup 0/C and observed for mortality along with the warm series. Though mortality was delayed in the cool series, each series reached 50% mortality at similar rates. Because the harvester ant is extremely tolerant to radiation and experimental rates used far exceed possible environmental exposure, it is unlikely that ant colonies dwelling among low-level nuclear waste storage sites will be deleteriously affected by radiation. This species has the capability of tunneling to a depth well within the range of some buried waste. Since these harvester ants are potential transporters of buried waste, they should be considered as a biotic factor in radioactive waste management operations in semi-arid regions.

  13. Mortality of the harvester ant (Pogonomyrmex owyheei) after exposure to /sup 137/Cs gamma radiation

    SciTech Connect

    Gano, K.A.

    1981-01-01

    Harvester ants, Pogonomyrmex owyheei Cole, irradiated with 3.5 kR to 268 kR of /sup 137/Cs gamma radiation, were maintained at simulated summer (27/sup 0/C) and winter (7/sup 0/C) temperature regimes. After thirty days, the cool series was warmed to 27/sup 0/C and observed for mortality along with the warm series.Though mortality was delayed in the cool series, each series reached 50% mortality at similar rates. Because the harvester ant is extremely tolerant to radiation and experimental rates used far exceed possible environmental exposure, it is unlikely that ant colonies dwelling among low-level nuclear waste storage sites will be deleteriously affected by radiation. This species has the capability of tunneling to a depth well within the range of some buried waste. Since these harvester ants are potential transporters of buried waste, they should be considered as a biotic factor in radioactive waste management operations in semi-arid regions.

  14. Up-regulation of Bcl-2 expression in cultured human lymphocytes after exposure to low doses of gamma radiation

    PubMed Central

    Azimian, Hosein; Bahreyni-Toossi, Mohammad Taghi; Rezaei, Abdul Rahim; Rafatpanah, Houshang; Hamzehloei, Tayebeh; Fardid, Reza

    2015-01-01

    Lymphocytes have demonstrated complex molecular responses to induced stress by ionizing radiation. Many of these reactions are mediated through modifications in gene expressions, including the genes involved in apoptosis. The primary aim of this study was to assess the effects of low doses of ionizing radiation on the apoptotic genes, expression levels. The secondary goal was to estimate the time-effect on the modified gene expression caused by low doses of ionizing radiation. Mononuclear cells in culture were exposed to various dose values ranged from 20 to 100 mGy by gamma rays from a Cobalt-60 source. Samples were taken for gene expression analysis at hours 4, 24, 48, 72, and 168 following to exposure. Expression level of two apoptotic genes; BAX (pro-apoptotic) and Bcl-2 (anti-apoptotic) were examined by relative quantitative real-time polymerase chain reaction (PCR), at different time intervals. Radio-sensitivity of peripheral blood mononucleated cells (PBMCs) was measured by the Bcl-2/BAX ratio (as a predictive marker for radio-sensitivity). The non-parametric two independent samples Mann–Whitney U-test were performed to compare means of gene expression. The results of this study revealed that low doses of gamma radiation can induce early down-regulation of the BAX gene of freshly isolated human PBMCs; however, these changes were restored to near normal levels after 168 hours. In most cases, expression of the Bcl-2 anti-apoptotic gene was up-regulated. Four hours following to exposure to low doses of gamma radiation, apoptotic gene expression is modified, this is manifested as adaptive response. Modification of these gene expressions seems to be a principle pathway in the early radioresistance response. In our study, we found that these changes were temporary and faded completely within a week.

  15. Inactivation of Bacillus Spores by Ultraviolet or Gamma Radiation

    Microsoft Academic Search

    Ernest R. Blatchley; Anne Meeusen; Arthur I. Aronson

    2005-01-01

    Bacillus anthracis spores represent an important bioterrorism agent that can be dispersed in air or water. Existing decontami- nation practices based on these spores have focused on chemical disinfectants; however, the basic characteristics of radiation-based disinfectants suggest potential advantages in their application for control of Bacillus spores. Experiments were conducted to examine the effectiveness of ultraviolet UV254 radiation and radiation

  16. Increased peak gamma frequency in individuals with higher levels of autistic traits.

    PubMed

    Dickinson, Abigail; Bruyns-Haylett, Michael; Jones, Myles; Milne, Elizabeth

    2015-04-01

    Individual differences in orientation discrimination threshold are related to both visually-induced peak gamma frequency and the presence of autistic traits. The relationship between peak gamma frequency and orientation discrimination thresholds may be due to both of these factors being mediated by levels of neural inhibition. No study has previously measured the relationship between peak gamma frequency and levels of autistic traits. Thus, this was the aim of the present study. We measured orientation discrimination thresholds and autistic traits in a neurotypical human sample (N = 33), and separately recorded electroencephalography to measure visually induced gamma activity. In line with our prediction, we found a significant relationship between peak gamma frequency and level of autistic traits. Consistent with previous work we also found significant relationships between orientation discrimination thresholds and level of autistic traits and between orientation discrimination thresholds and peak gamma frequency. Our results demonstrate that individuals with individuals with higher levels of autistic personality traits have a higher peak-gamma frequency and are better at discriminating between visual stimuli based on orientation. As both higher peak gamma frequency and lower orientation discrimination thresholds have been linked to higher levels of neural inhibition, this suggests that autistic traits co-occur with increased neural inhibition. This discovery is significant as it challenges the currently-held view that autism spectrum conditions are associated with increased neural excitation. PMID:25858292

  17. Absorption of 10--200 Gev Gamma Rays by Radiation from BLR in Blazars

    E-print Network

    H. T. Liu; J. M. Bai

    2008-07-20

    In this paper, we study the photon-photon pair production optical depth for gamma-rays with energies from 10 to 200 GeV emitted by powerful blazars due to the diffuse radiation field of broad line region (BLR). There are four key parameters in the BLR model employed to determine the $\\gamma-\\gamma$ attenuation optical depth of these gamma-rays. They are the gamma-ray emitting radius $R_{\\gamma}$, the BLR luminosity $L_{\\rm{BLR}}$, the BLR half thickness $h$ and the ratio $\\tau_{\\rm{BLR}}/f_{\\rm{cov}}$ of the Thomson optical depth to the covering factor of BLR. For FSRQs, on average, it is impossible for gamma-rays with energies from 10 to 200 GeV to escape from the diffuse radiation field of the BLR. If $\\it GLAST$ could detect these gamma-rays for most of FSRQs, the gamma-ray emitting region is likely to be outside the cavity formed by the BLR. Otherwise, the emitting region is likely to be inside the BLR cavity. As examples, we estimate the photon-photon absorption optical depth of gamma-rays with energies from 10 to 200 GeV for two powerful blazars, HFSRQ PKS 0405$-$123 and FSRQ 3C 279. Comparing our results with $\\it GLAST$ observations in the future could test whether the model employed and the relevant assumptions in this paper are reliable and reasonable, and then limit constraints on the position of the gamma-ray emitting region relative to the BLR and the properties of the BLR.

  18. Gamma-radiation-induced degradation of actively pumped single-mode ytterbium-doped optical fibers

    NASA Astrophysics Data System (ADS)

    Singleton, B.; Petrosky, J.; Pochet, M.; Usechak, N. G.; Francis, S. A.

    2014-03-01

    The integration of optical components into the digital processing units of satellite subsystems has the potential to remove interconnect bottlenecks inherent to the volume, mass, complexity, reliability and crosstalk issues of copper-based interconnects. Assuming on-board high-bandwidth communications will utilize passive optical fibers as a communication channel, this work investigates the impact of gamma irradiation from a Co-60 source on both passive optical fibers and ytterbium-doped single-mode fibers operated as amplifiers for a 1060-nm light source. Standard optical patch cables were evaluated along with active Yb-doped double-clad fibers. Varied exposure times and signal transmission wavelengths were used to investigate the degradation of the fibers exposed to total doses above 100 krad (Si). The effect on the amplified signal gain was studied for the Yb-doped fibers. The increased attenuation in the fibers across a broad wavelength range in response to multiple levels of gamma radiation exposure along with the effect that the increased attenuation has on the actively pumped Yb-doped fiber amplifier performance, is discussed.

  19. Formulation of a nasogastric liquid feed and shelf-life extension using gamma radiation.

    PubMed

    Hajare, Sachin N; Gautam, Satyendra; Nair, Anjali B; Sharma, Arun

    2014-08-01

    Nasogastric liquid feed formulation (NGLF) was developed for immunocompromised patients who are vulnerable targets of pathogenic assault. NGLF consisted of cereals, pulses, vegetables, and milk powder to provide balanced nutrients; however, the shelf life was only a few hours because this product was highly prone to microbial contamination and proliferation due to its high water content and rich nutrients. Postpreparation storage and distribution was very difficult, even at chilled temperatures. To overcome this problem, the NGLF was irradiated at various doses (2.5 to 10 kGy). Gamma irradiation at 10 kGy reduced the microbial load to nondetectable levels, and the product could be stored up to 1 month without any detectable increase in microbial load. The sensory evaluation did not indicate differences between the nonirradiated fresh, irradiated fresh, and stored samples. Nutritional quality in terms of total carbohydrates, dietary fiber, proteins, calories, vitamins A and C, and the micronutrients calcium, iron, and zinc was not affected by irradiation. NGLF also possessed antimutagenic potential against ethylmethanesulphonate-induced mutagenesis in Escherichia coli cells as evaluated by the rifampin resistance assay. This property of NGLF remained unchanged even after exposure to a 10-kGy dose of gamma radiation. Thus, irradiated NGLF seemed to be a safe and wholesome food for immunocompromised patients. PMID:25198591

  20. Extending the response of the sum coincidence spectrometer to multiple gamma radiation cascades 

    E-print Network

    Helton, Victor Dean

    1964-01-01

    for the degree of MASTER OF SCIENCE August, l964, Major Subject: Physics EXTENDING THE RESPONSE OF THE SUM COINCIDENCE SPECTROMETER TO MULTIPLE GAMMA RADIATION CASCADES A Thesis By VICTOR DEAN HELTON Approved as to style and content by: i / C airman... BIBLIOGRAPHY ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ o ~ 52 LIST OF FIGURES Figure Page 1. The Sum Coincidence Spectrometer . ~ ~ ~ ~ ~ ~ 11 2. The Three Gamma-Ray Cascade . . . . . . . . . 14 3 The Coincidence-Sum Spectrometer . . . . . . . 20 4, ~ 5...

  1. Amplification of Gamma Radiation from X-Ray Excited Nuclear States

    E-print Network

    Silviu Olariu

    1999-07-18

    In this paper we discuss the possibility of the excitation of nuclear electromagnetic transitions by the absorption of X-ray quanta produced in appropriate inner-shell atomic transitions, and the relevance of this process for the amplification of the gamma radiation from the excited nuclear states. It is concluded that the X-ray pumping technique might provide a useful approach for the development of a gamma ray laser.

  2. HEALTH HAZARDS FROM FISSION PRODUCTS AND FALLOUT. II. GAMMA RADIATION FROM NUCLEAR WEAPONS FALLOUT

    Microsoft Academic Search

    Bjornerstedt

    1960-01-01

    Methods of estimating the gamma radiation from fallout and fission ; products are discussed. (Gamma spectra and 0.1 Mev energy intervals for 101 ; fissions were calculated for the following times after fission: 1. 2. 5. and 10 ; hours; years. Fifty energy groups of width 1.300 to 1.399 Mev were used, ; covering the range 0.0 to 5.0 Mev.

  3. Gamma-Ray Induced Radiation Damage in Large Size LSO and LYSO Crystal Samples

    Microsoft Academic Search

    Jianming Chen; Rihua Mao; Liyuan Zhang; Ren-Yuan Zhu

    2007-01-01

    This paper presents a study of the gamma-ray induced radiation damage effect in large size (2.5 times 2.5 times 20 cm3) LSO and LYSO crystal samples. Optical and scintillation properties, including longitudinal transmittance and photo-luminescence spectra, light output and light response uniformity with PMT and APD readout, are measured before and after gamma-ray irradiations with an integrated dose up to

  4. A radiation transport model as a design tool for gamma densitometers

    Microsoft Academic Search

    E. Åbro; G. A. Johansen; H. Opedal

    1999-01-01

    A flexible EGS4 Monte Carlo model was developed to simulate radiation transport in low-energy gamma-ray densitometers which are used for void (gas) fraction measurements in gas\\/liquid pipe flows. The detector responses produced by the model with 241Am gamma-ray input proved to be accurate in benchmarking experiments using real data. The verification was performed with homogeneous mixed flows at different void

  5. Sensitivity of hyperthermia-treated human cells to killing by ultraviolet or gamma radiation

    SciTech Connect

    Mitchel, R.E.; Smith, B.P.; Wheatly, N.; Chan, A.; Child, S.; Paterson, M.C.

    1985-11-01

    Human xeroderma pigmentosum (XP) or Fanconi anemia (FA) fibroblasts displayed shouldered 45/sup 0/C heat survival curves not significantly different from normal fibroblasts, a result similar to that previously found for ataxia telangiectasia (AT) cells, indicating heat resistance is not linked to either uv or low-LET ionizing radiation resistance. Hyperthermia (45/sup 0/C) sensitized normal and XP fibroblasts to killing by gamma radiation but failed to sensitize the cells to the lethal effects of 254 nm uv radiation. Thermal inhibition of repair of ionizing radiation lesions but not uv-induced lesions appears to contribute synergistically to cell death. The thermal enhancement ratio (TER) for the synergistic interaction of hyperthermia (45/sup 0/C, 30 min) and gamma radiation was significantly lower in one FA and two strains (TER = 1.7-1.8) than that reported previously for three normal strains (TER = 2.5-3.0). These XP and FA strains may be more gamma sensitive than normal human fibroblasts. Since hyperthermia treatment only slightly increases the gamma-radiation sensitivity of ataxia telangiectasia (AT) fibroblasts compared to normal strains, it is possible that the degree of thermal enhancement attainable reflects the genetically inherent ionizing radiation repair capacity of the cells. The data indicate that both repair inhibition and particular lesion types are required for lethal synergism between heat and radiation. We therefore postulate that the transient thermal inhibition of repair results in the conversion of gamma-induced lesions to irrepairable lethal damage, while uv-type damage can remain unaltered during this period.

  6. Natural radioactivity and external gamma radiation exposure at the coastal Red Sea in Egypt.

    PubMed

    Harb, S

    2008-01-01

    Radionuclides which present in different beach sands are sources of external exposure that contribute to the total radiation exposure of human. In this work, superficial samples of beach sand were collected from the Red Sea coastline (Ras Gharib, Hurghada, Safaga, Qusier and Marsa Alam areas) and at 20 km on Qena-Safaga road. The distribution of natural radionuclides in sand beach samples was studied by gamma spectrometry. The activity concentrations of primordial and artificial radionuclides in samples that are collected from the coastal environment of the Red Sea were 19.2 +/- 3 Bq kg(-1) for (210)Pb, 21.1 +/- 1 Bq kg(-1) for (226)Ra, 22.7 +/- 2 Bq kg(-1) for (238)U, 1.0 +/- 0.1 Bq kg(-1) for (235)U, 11.6 +/- 1 Bq kg(-1) for (228)Ra, 13.0 +/- 1 Bq kg(-1) for (228)Th, 12.4 +/- 1 Bq kg(-1) for (232)Th, 930 +/- 32 Bq kg(-1) for (40)K and 1.2 +/- 0.3 Bq kg(-1) for (137)Cs. The mean external gamma-dose rate was 62.5 +/- 3.2 nSv h(-1), 54.4 +/- 2.8 nGy h(-1) Ra equivalent activity (Ra(eq)) was 107 +/- 5.8 Bq kg(-1), 0.86 +/- 0.04 Bq kg(-1) for representative level index (I(gamma)) and effective dose rate was 0.067 +/- 0.003 mSv y(-1) in beach sand red sea, in air due to naturally occurring radionuclides. PMID:18337293

  7. Application of a CdTe gamma-ray spectrometer to remote characterization of high-level radioactive waste tanks

    SciTech Connect

    Addleman, R.S.; Blewett, G.R.; Keele, B.D.; McClellan, C.S.; Subrahmanyam, V.B.; Troyer, G.L.

    1993-04-01

    Small, shielded cadmium telluride (CdTe) semiconductor gamma-ray detectors have been used for in situ radiological characterization of underground high-level radioactive waste tanks. Remote measurements have been made in gamma radiation fields up to 700 R/h. Spectral data have been used to generate qualitative and quantitative radionuclide profiles of high-level radioactive waste tanks. Two electronic spectral enhancement techniques (pulse risetime discrimination and pulse risetime compensation) have been used in order to measure trace isotopes with photopeak energies greater than 662keV in the presence of large amounts of {sup 137}Cs. Spectral resolution of 1.5% for the {sup 137}Cs 662 keV photopeak has been obtained.

  8. Application of a CdTe gamma-ray spectrometer to remote characterization of high-level radioactive waste tanks

    SciTech Connect

    Keele, B.D.; Addleman, R.S.; Blewett, G.R.; McClellan, C.S.; Subrahmanyam, V.B.; Troyer, G.L.

    1991-10-01

    Small, shielded cadmium telluride (CdTe) semiconductor gamma-ray detectors have been used for in situ radiological characterization of underground high-level radioactive waste tanks. Remote measurements up to 700 R/h have been made in gamma radiation fields. Spectral data have been used to generate qualitative and quantitative radionuclide profiles of high-level radioactive waste tanks. Two electronic spectral enhancement techniques (pulse risetime discrimination and pulse risetime compensation) have been used in order to measure trace isotopes in the presence of large amounts of {sup 137}Cs. Spectral resolution better than 1.5% FWHM for the {sup 137}Cs 662 keV photopeak has been obtained. 4 refs., 7 figs.

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

    PubMed

    Ciupek, K; Aksamit, D; Wo?oszczuk, 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. PMID:25009188

  10. SAS-2 observations of the high energy gamma radiation from the Vela region

    NASA Technical Reports Server (NTRS)

    Thompson, D. J.; Bignami, G. F.; Fichtel, C. E.; Kniffen, D. A.

    1974-01-01

    Data from a scan of the galactic plane by the SAS-B high energy gamma ray experiment in the region 250 deg smaller than 12 smaller than 290 deg show a statistically significant excess over the general radiation from the galactic plane for gamma radiation of energy larger than 100 MeV. If the enhanced gamma radiation results from interactions of cosmic rays with galactic matter, as the energy spectrum suggests, it seems reasonable to associate the enhancement with large scale galactic features, such as spiral arm segments in that direction, or with the region surrounding the Vela supernova remnant with which PSR 0833-45 is associated. If the excess is attributed to cosmic rays released from the supernova interacting with the interstellar matter in that region, than on the order of 3 x 10 to the 50th power ergs would have been released by that supernova in the form of cosmic rays.

  11. 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.

  12. Radiomodulatory role of Rutin and Quercetin in Swiss Albino mice exposed to the whole body gamma radiation

    PubMed Central

    Patil, Shrikant L; Somashekarappa, HM; Rajashekhar, KP

    2012-01-01

    Context: Radiation therapy is the prime treatment modality against various cancers. However, its use is limited due to the effects of radiation on normal tissues. Aims: In view of this, present study was carried out to evaluate the radioprotective potential of Rutin (RUT) and Quercetin (QRT) in Swiss Albino mice exposed to the whole body gamma radiation. To gain insight into the mechanism of action, RUT and QRT were tested for its antioxidant levels in mice. Settings and Designs: Optimum protective dose of RUT and QRT against radiation induced animal mortality was selected by administration of various doses of the RUT and QRT before 10 Gy gamma irradiation. Materials and Methods: Swiss Albino mice were used for the assessment of radiation induced sickness along with the survival analysis and anti-oxidative properties of RUT and QRT. Statistical Analysis Used: Survival studies were determined using the Kaplan-Meier survival curves. Results: The maximum survival was observed with 10 mg/kg. b. wt. and 20 mg/kg. b. wt. of RUT and QRT respectively, this dose was considered as an optimal dose for radioprotection. Treatment of mice with RUT and QRT before irradiation delayed the onset of mortality as compared with the untreated irradiated controls. The oral administration of RUT and QRT resulted in an increase in the radiation tolerance and the dose reduction factor was found to be 1.15 and 1.11 respectively. RUT and QRT pre-treatment significantly (P < 0.01) elevated levels of reduced glutathione, glutathione-S-transferase, catalase, Superoxide dismutase, and a decreased lipid peroxidation in mouse liver homogenate at 24 h after exposure to 4.5 Gy. Conclusions: Present findings demonstrate the potential of RUT and QRT in mitigating radiation-induced mortality, which may be attributed to the elevation in the antioxidant status, anti-lipid peroxidative potential. PMID:24019653

  13. Radiation levels on empty cylinders containing heel material

    SciTech Connect

    Shockley, C.W. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    Empty UF{sub 6} cylinders containing heel material were found to emit radiation levels in excess of 200 mr/hr, the maximum amount stated in ORO-651. The radiation levels were as high as 335 mr/hr for thick wall (48X and 48Y) cylinders and 1050 mr/hr for thin wall (48G and 48H) cylinders. The high readings were found only on the bottom of the cylinders. These radiation levels exceeded the maximum levels established in DOT 49 CFR, Part 173.441 for shipment of cylinders. Holding periods of four weeks for thick-wall cylinders and ten weeks for thin-wall cylinders were established to allow the radiation levels to decay prior to shipment.

  14. Radiation effects of helium ions, neutrons, and gamma-rays on photo-stimulated luminescence

    NASA Astrophysics Data System (ADS)

    Kobayashi, Hisao; Shibata, Hiromi; Eguchi, Hoshio; Sato, Masanori; Etoh, Masahiro; Takebe, Masahiro; Abe, Ken

    1998-02-01

    A photo-stimulated luminescent (PSL) material, BaFBr 0.85I 0.15 : Eu 2+, was irradiated by 1 and 2 MeV He + ions. The radiation effects were compared with that of fission neutrons, 137Cs and 60Co gamma-rays. Deterioration of PSL signals was measured as a function of total fluence for ions and neutrons or dose for gamma-rays. Relative deteriorations for neutrons and gamma-rays were compared with that of 1 MeV He + ion irradiation. A self-generation of PSL signals depending on fluence and storage time was observed.

  15. 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 (50-200Gy) 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 200Gy were 12.6 and 38.8Mn/1000 cells in T. castaneum, 20.8 and 46.8Mn/1000 cells in C. maculatus and 16.8 and 57.2Mn/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. PMID:25898238

  16. Lunar radiation environment: a study by using Kaguya gamma-ray spectrometer and Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Kobayashi, Shingo; Hayatsu, Kanako; Uchihori, Yukio; Hareyama, Makoto; Hasebe, Nobuyuki; Fujibayashi, Yukari

    2012-07-01

    We have continued to improve the estimation of radiation dose on the Moon based on observation by remote sensing and calculation of the transportation of cosmic-ray particles in the lunar materials in order to provide basic data for a future manned lunar exploration. On the lunar surface, the dose of primary galactic cosmic rays (pGCR) is the most significant and the contributions of neutrons and gamma rays are relatively small and are approximately 10% and 1% of that of pGCR, respectively. However, these percentages are changed by use of thick shieldings and also geographical feature of the lunar surface, such as margin of a huge boulder, bottom of a pit, inside of a possible lava tube. In this case, the dose by pGCRs is moderated and the contributions of neutrons and gamma rays relatively increase. Here, we show the recent estimation of spatial variation of the lunar dose due to gamma ray and neutrons measured by Kaguya gamma-ray spectrometer. The energy spectrum of gamma rays from the lunar surface are precisely measured by a germanium (Ge) gamma-ray spectrometer onboard the Japanese lunar orbiter (Kaguya/SELENE). The flux of fast neutrons from the lunar surface was also measured by detecting the characteristic gamma rays due to the neutron inelastic reaction with the Ge of the spectrometer, that is 72Ge(n, n'g)72Ge. The estimation of radiation dose on the Moon based on Monte Carlo simulation will also be presented.

  17. 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.

  18. Search for Bremsstrahlung radiation in quasi-free n p --> n p gamma reactions

    E-print Network

    Przerwa, J; Budzanowski, A; Czyzykiewicz, R; Grzonka, D; Janusz, M; Jarczyk, L; Kamys, B; Khoukaz, A; Kilian, K; Klaja, P; Lang, N; Moskal, P; Oelert, W; Piskor-Ignatowicz, C; Rozek, T; Santo, R; Sefzick, T; Siemaszko, M; Smyrski, J; Täschner, A; Winter, P; Wolke, M; Wüstner, P; Zipper, W

    2004-01-01

    Due to the high sensitivity of the N N --> N N gamma reaction to the nucleon-nucleon potential, Bremsstrahlung radiation is used as a tool to investigate details of the nucleon-nucleon interaction. Such investigations can be performed at the cooler synchrotron COSY in the Research Centre Juelich, by dint of the COSY-11 detection system. The results of the identification of Bremsstrahlung radiation emitted via the d p --> d p gamma reaction in data taken with a proton target and a deuteron beam are presented and discussed.

  19. Search for Bremsstrahlung radiation in quasi-free n p --> n p gamma reactions

    E-print Network

    J. Przerwa; H. -H. Adam; A. Budzanowski; R. Czyzykiewicz; D. Grzonka; M. Janusz; L. Jarczyk; B. Kamys; A. Khoukaz; K. Kilian; P. Klaja; N. Lang; P. Moskal; W. Oelert; C. Piskor-Ignatowicz; T. Rozek; R. Santo; T. Sefzick; M. Siemaszko; J. Smyrski; A. Taeschner; P. Winter; M. Wolke; P. Wuestner; W. Zipper

    2004-07-21

    Due to the high sensitivity of the N N --> N N gamma reaction to the nucleon-nucleon potential, Bremsstrahlung radiation is used as a tool to investigate details of the nucleon-nucleon interaction. Such investigations can be performed at the cooler synchrotron COSY in the Research Centre Juelich, by dint of the COSY-11 detection system. The results of the identification of Bremsstrahlung radiation emitted via the d p --> d p gamma reaction in data taken with a proton target and a deuteron beam are presented and discussed.

  20. Effects of low levels of radiation on humans

    SciTech Connect

    Auxier, J.A.

    1981-01-01

    The state of knowledge on effects of low-level ionizing radiations on humans is reviewed. Several problems relating to dose thresholds or lack of thresholds for several types of cancer and high LET radiations and the effects of fractionation and dose protection are discussed. (ACR)

  1. 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.

  2. Preparation of polyester/gypsum/composite using gamma radiation, and its radiation stability

    NASA Astrophysics Data System (ADS)

    Ajji, Zaki

    2005-06-01

    Composites based on pure gypsum and polyester-styrene resin have been prepared using various doses of gamma radiation. Some physical properties of the prepared composites and the influence of irradiation dose on it have been studied as: compression strength, hardness, thermal decomposition temperature in nitrogen or oxygen, and the change in weight in aqueous solutions with different pH values. The glass transition temperature of the pure polymer and the composites increases with increasing the irradiation dose up to a plateau, and the glass transition temperature of the pure polymer is lower than that of the composites. The irradiation dose does not seem to affect the decomposition temperature of the pure polymer or the composites significantly and the decomposition temperature in presence of nitrogen is higher than that in presence of oxygen. Increasing the irradiation dose leads to an enhancement of the compression strength of the pure polymer and the prepared composites; the hardness of the pure polymer and the composites seems to be constant versus the irradiation dose. Soaking experiments show that the weight of composites does not change in distilled and alkaline medium, but there is a limited decrease in acidic medium of about 3% after 1560 h.

  3. Radiation levels in the SSC interaction regions

    SciTech Connect

    Groom, D.E. [ed.

    1988-06-10

    The radiation environment in a typical SSC detector has been evaluated using the best available particle production models coupled with Monte Carlo simulations of hadronic and electromagnetic cascades. The problems studied include direct charged particle dose, dose inside a calorimeter from the cascades produced by incident photons and hadrons, the flux of neutrons and photons backscattered from the calorimeter into a central cavity, and neutron flux in the calorimeter. The luminosity lifetime at the SSC is dominated by collision losses in the interaction regions, where the luminosity is equivalent to losing an entire full-energy proton beam into the apparatus every six days. The result of an average p-p collision can be described quite simply. The mean charged multiplicity is about 110, and the particles are distributed nearly uniformly in pseudorapidity ({eta}) over all the angles of interest. The transverse momentum distribution is independent of angle, and for our purposes may be written as p{perpendicular}exp(-p{perpendicular}/{beta}). The mean value of p{perpendicular} may be as high as 0.6 GeV/c. Most of the radiation is produced by the very abundant low-p{perpendicular} particles. The dose or neutron fluence produced by individual particles in this energy region are simulated over a wide variety of conditions, and several measurements serve to confirm the simulation results. In general, the response (a dose, fluence, the number of backscattered neutrons, etc.) for an incident particle of momentum p can be parameterized in the form Np{sup {alpha}}, where 0.5 < {alpha}< 1.0. The authors believe most of their results to be accurate to within a factor of two or three, sufficiently precise to serve as the basis for detailed designs.

  4. The high energy gamma-ray background and the interstellar radiation field

    NASA Astrophysics Data System (ADS)

    Chary, Ranga-Ram

    This thesis provides an independent estimate of the high latitude (! b! > 20°) contribution to the E > 30 MeV gamma-ray background from Galactic nucleon-nucleon, electron bremsstrahlung and inverse Compton processes. In particular, the inverse Compton contribution has been estimated for different cosmic ray electron distributions and after factoring in the anisotropy in the interstellar radiation field and the anisotropic Klein-Nishina scattering cross section. A model for the interstellar radiation field from 0.1 ?m to 1000 ?m is also presented to fit the intensities observed by recent satellite experiments, especially the DIRBE and FIRAS instruments on COBE. I find that the emission from the inverse Compton process when the anisotropy in the radiation field is included can be higher by up to 50% when compared to estimates that adopt an isotropic radiation field. Simulated inverse Compton maps with a cosmic ray electron distribution represented by a ``pill box'' extending up to a distance of 5 kpc above the Galactic plane provide better fits to the EGRET intensity maps suggesting that the cosmic ray halo may be larger than previously thought. With this distribution, I find that the net contribution from the IC process to the gamma-ray background can be as high as 20% at high Galactic latitudes. Fitting for the Galactic components of gamma-ray emission confirms the existence of an isotropic component with an intensity that can be represented by the form 27.7 × E(MeV)-2.16 photons m-2 s-1 sr -1 MeV-1, in excellent agreement with previous estimates. The spectrum of the isotropic component further argues strongly in favor of unresolved gamma-ray blazars being the source of this emission. Introduction of an anisotropic component improves the quality of the fits. However, this component, which could potentially arise from the dark matter in the Galactic halo, is not well characterized by a single power law which might be associated with any single dark matter candidate. It has an intensity of about a third of the isotropic background above E > 100 MeV-1, at the level of 3 × 10-2 photons m-2 s-1 sr-1 . The best fit power law spectrum to this component has a photon index of -1.7. Based on the intensity and spectrum of the anisotropic component I derive upper limits of 109Msolar for the mass of cold, baryonic gas within the solar circle and a primordial black hole number density limit of 7 × 107 pc -3 which is more than an order of magnitude smaller than previous limits. If the spectrum of the anisotropic component is indeed confirmed to have an index of -1.7, it appears more likely that the signal arises in unresolved Galactic sources such as pulsars.

  5. Radiation detection system for portable gamma-ray spectroscopy

    DOEpatents

    Rowland, Mark S. (Alamo, CA); Howard, Douglas E. (Livermore, CA); Wong, James L. (Dublin, CA); Jessup, James L. (Tracy, CA); Bianchini, Greg M. (Livermore, CA); Miller, Wayne O. (Livermore, CA)

    2006-06-20

    A portable gamma ray detection apparatus having a gamma ray detector encapsulated by a compact isolation structure having at least two volumetrically-nested enclosures where at least one is a thermal shield. The enclosures are suspension-mounted to each other to successively encapsulate the detector without structural penetrations through the thermal shields. A low power cooler is also provided capable of cooling the detector to cryogenic temperatures without consuming cryogens, due to the heat load reduction by the isolation structure and the reduction in the power requirements of the cooler. The apparatus also includes a lightweight portable power source for supplying power to the apparatus, including to the cooler and the processing means, and reducing the weight of the apparatus to enable handheld operation or toting on a user's person.

  6. Efficient modeling of Compton diode gamma radiation detectors

    Microsoft Academic Search

    D. R. Drumm; J. J. Hohlfelder; J. D. Kotulski; G. J. Scrivner; G. S. Mills; T. J. Tanaka

    1991-01-01

    The CEPXS\\/ONELD code package proves to be significantly more efficient than electron Monte Carlo for computing the spherical Compton diode response to gamma irradiation, requiring only minutes instead of hours of Cray computer time. The adjoint capability of CEPXS\\/ONELD allows the complete energy-angle response of a Compton diode to be determined with a single transport calculation. The method is a

  7. Efficient modeling of Compton diode gamma radiation detectors

    Microsoft Academic Search

    C. R. Drumm; J. J. Hohlfelder; J. D. Kotulski; G. J. Scrivner; G. S. MillsandT; T. J. Tanaka

    1992-01-01

    The CEPXS\\/ONELD code package proved to be significantly more efficient than electron Monte Carlo for computing spherical Compton diode response to gamma irradiation. The authors review the mechanism responsible for the production of electric currents in Compton diodes, describe the calculation method, and present results for a few representative Compton diodes. The adjoint capability of CEPXS\\/ONELD allows the complete energy-angle

  8. Microbiological, chemical, and sensory quality changes in Pico de gallo as affected by gamma radiation 

    E-print Network

    Miller, Gerald Howard

    1994-01-01

    by radiation and storage. Pectin solubility was affected by radiation treatment and storage. Radiation resulted in conversion of CSP to NXP. Levels of WSP and NXP increased in both treatments during storage, while levels of CSP and OHSP decreased. Pectins were...

  9. Effects of high vs low-level radiation exposure

    SciTech Connect

    Bond, V.P.

    1983-01-01

    In order to appreciate adequately the various possible effects of radiation, particularly from high-level vs low-level radiation exposure (HLRE, vs LLRE), it is necessary to understand the substantial differences between (a) exposure as used in exposure-incidence curves, which are always initially linear and without threshold, and (b) dose as used in dose-response curves, which always have a threshold, above which the function is curvilinear with increasing slope. The differences are discussed first in terms of generally familiar nonradiation situations involving dose vs exposure, and then specifically in terms of exposure to radiation, vs a dose of radiation. Examples are given of relevant biomedical findings illustrating that, while dose can be used with HLRE, it is inappropriate and misleading the LLRE where exposure is the conceptually correct measure of the amount of radiation involved.

  10. Zener diodes for gamma-ray radiation dosimetry

    Microsoft Academic Search

    Shigeki Nakamura; Shinichi Okamoto

    1995-01-01

    The fundamental properties of Zener diodes and junction field-effect transistors have been studied to use them as a relative dose monitor or a radiation-damage monitor. The response observed at liquid nitrogen temperature, i.e., radiation-induced change in the breakdown voltage of the Zener diode, or change in the breakdown voltage of the pn junction between the gate and the channel (or

  11. Effect of /sup 60/Co /gamma/-radiation on aqueous solutions of acrylamide

    SciTech Connect

    Zhestkova, T.P.; Misevich, B.S.; Kotov, A.V.

    1988-07-01

    Data were obtained on the dependence of the index of refraction (ir) of aqueous solutions of acrylamide on the absorbed dose of /sup 60/Co /gamma/-radiation. The calculated data on the dependence of ir on the degree of polymerization are reported. Using calculations of polymer models and the IR spectra, it was shown that the increase in the ir of the irradiated solution is due to oxidative processes which take place in the polymer formed under the effect of the radiation.

  12. Radiation protection by disulfiram: protection of membrane and DNA in vitro and in vivo against gamma-radiation.

    PubMed

    Gandhi, Nitin Motilal; Gopalaswamy, Usulumarty Venu; Nair, Cherupally rishnan K

    2003-09-01

    Disufiram (a drug used for the treatment of alcoholism) protected microsomal membranes and plasmid DNA against damages induced by gamma-radiation. The peroxidation of membrane lipids increased linearly with the radiation dose up to 600 Gy, and the presence of disulfiram inhibited membrane lipid peroxidation as assayed by the presence of thiobarbituric acid reacting substances. The reduction of the quantity of the supercoiled (ccc) form of plasmid pBR322 DNA is directly related to the radiation-induced damage, particularly to DNA strand breaks. There was a complete protection of plasmid DNA when exposed to gamma-radiation in the presence of disufiram (0.1 mM) at 300 Gy. This drug also protected deoxyribose against damages caused by hydroxyl radicals produced by the Fenton reaction. The administration of DSF to mice prior to whole-body radiation exposure (4 Gy) resulted in a reduction of peroxidation of membrane lipids in mice liver as well as a decrease in radiation-induced damage to cellular DNA, as assayed by single-cell gel electrophoresis (comet assay). The results thus suggest the possible use of DSF as a radioprotector. PMID:14646230

  13. 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.

  14. Testicular damage and regeneration in rats following low-level gamma irradiation 

    E-print Network

    Maxwell, Wesley Howard

    1974-01-01

    TESTICULAR DAMAGE AND REGENERATION IN RATS FOLLOWING LOW-LEVEL GAMMA IRRADIATION A Thesis by Wesley Howard Maxwell Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE December 1974 Major Subject: Zoology TESTICULAR DAMAGE AND REGENERATION IN RATS FOLLOWING LOW-LEVEL GAMMA IRRADIATION A Thesis by Wesley Howard Maxwell Approved as to style and content by: 'airman f Committee) (Head of Department...

  15. Prediction of radiation dosimetry in patients with thyroid cancer using a Gamma camera

    Microsoft Academic Search

    G. L. De Nardo; D. J. Macey; S. J. De Nardo; D. A. Adams

    1985-01-01

    Radioiodine in the thyroid or cervical metastases, and therefore radiation dosimetry, can be determined using a probe and phantom. This approach is not ideal for quantitating radioiodine and dosimetry for sites elsewhere in the body. The authors have studied the use of gamma camera methods in association with I-123 to predict the distribution of I-131 and its dosimetry in 3

  16. The production and composition of rat sebum is unaffected by 3 Gy gamma radiation

    PubMed Central

    Lanz, Christian; Ledermann, Monika; Slavík, Josef; Idle, Jeffrey R.

    2013-01-01

    Purpose The aim of this work was to use metabolomics to evaluate sebum as a source of biomarkers for gamma-radiation exposure in the rat, and potentially in man. Proof of concept of radiation metabolomics was previously demonstrated in both mouse and rat urine, from the radiation dose- and time-dependent excretion of a set of urinary biomarkers. Materials and methods Rats were gamma-irradiated (3 Gy) or sham irradiated and groups of rats were euthanised at 1 h or 24 h post-irradiation. Sebum was collected by multiple washings of the carcasses with acetone. Nonpolar lipids were extracted, methylated, separated and quantitated using gas chromatography-mass spectrometry (GCMS). Metabolomic analysis of the GCMS data was performed using both orthogonal projection to latent structures-discriminant analysis and random forests machine learning algorithm. Results Irradiation did not alter sebum production. A total of 35 lipids were identified in rat sebum, 29 fatty acids, five fatty aldehydes, and cholesterol. Metabolomics showed that three fatty acids, palmitic, 2-hydroxypalmitic, and stearic acids were potential biomarkers. Sebaceous palmitic acid was marginally statistically significantly elevated (7.5–8.4%) at 24 h post-irradiation. Conclusions Rat sebaceous gland appears refractory to 3 Gy gamma-irradiation. Unfortunately, collection of sebum shortly after gamma-irradiation is unlikely to form the basis of high-throughput non-invasive radiation biodosimetry in man. PMID:21158499

  17. An integrated systems approach for understanding cellular responses to gamma radiation

    Microsoft Academic Search

    Kenia Whitehead; Adrienne Kish; Min Pan; Amardeep Kaur; David J Reiss; Nichole King; Laura Hohmann; Jocelyne DiRuggiero; Nitin S Baliga

    2006-01-01

    Cellular response to stress entails complex mRNA and protein abundance changes, which translate into physiological adjustments to maintain homeostasis as well as to repair and minimize damage to cellular components. We have characterized the response of the halophilic archaeon Halobacterium salinarum NRC-1 to 60Co ionizing gamma radiation in an effort to understand the correlation between genetic information processing and physiological

  18. Gamma-ray dose assessment after the 1994 radiation accident in Kiisa (Estonia): Preliminary results

    Microsoft Academic Search

    G. Hütt; L. Brodski; V. Polyakov

    1996-01-01

    Dose reconstruction using thermoluminescence (TL) of quartz, extracted from the ceramic plant pots, and using EPR of the sugar samples, was performed after the 1994 radiation accident in the village Kiisa (Estonai). A gamma-ray source 137Cs was located during approx. 28 days in one of the village dwelling houses. On the basis of preliminary results, some important details of the

  19. Gamma radiation inactivation of non-0157:H7 shiga-toxin producing Escherichia coli in foods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Non-O157:H7 serovars of shiga-toxin producing Escherichia coli are emerging foodborne pathogens that have been associated with illness outbreaks and food product recalls on a global basis. Ionizing (gamma) radiation is a nonthermal food safety intervention technology that has been approved for use i...

  20. 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. ?-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

  1. 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. ?-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

  2. Radiative decay Y(4260) -> X(3872) + gamma involving hadronic molecular and charmonium components

    E-print Network

    Yubing Dong; Amand Faessler; Thomas Gutsche; Valery E. Lyubovitskij

    2014-10-29

    We apply a phenomenological Lagrangian approach to the radiative decay Y(4260) -> X(3872) + gamma. The Y(4260) and X(3872) resonances are considered as composite states containing both molecular hadronic and charmonium components. Having a leading molecular component in the X(3872) and a sole molecular configuration for the Y(4260) results in a prediction compatible with present data.

  3. Use of PCR for Detecting Aspergillus flavus in Maize Treated by Gamma Radiation Process

    Microsoft Academic Search

    Simone Aquino; Ralf Greiner; Ursula Konietzny; Regina H. Hassegawa; Tatiana Alves dos Reis; Benedito Corrêa; Anna Lucia C. H. Villavicencio

    2008-01-01

    The aim of this study was to verify the effects of gamma radiation process on the fungal DNA and the application of PCR in the detection of Aspergillus flavus in irradiated maize grains. The samples were inoculated with a toxigenic strain and incubated under controlled conditions of relative humidity, water activity, and temperature for 15 days. After incubation, the samples

  4. Short-lived variations in the background gamma-radiation dose.

    PubMed

    Burnett, J L; Croudace, I W; Warwick, P E

    2010-09-01

    Sudden increases in the background gamma-radiation dose may occur due to the removal of (222)Rn and (220)Rn progeny from the atmosphere by wet deposition mechanisms. This contribution has been measured using a Geiger-Muller detector at the Atomic Weapons Establishment (Aldermaston, UK) during July 2005-April 2006. The results are approximated by a log-normal distribution and there were nine separate occurrences of the gamma-radiation dose exceeding 125% of the geometric mean value. The increases were associated with periods of heavy rainfall, although no correlation was evident between the dose rate and the amount of rainfall, as increased rainfall dilutes the activity further rather than increasing its atmospheric removal. The events were preceded by periods of fine weather and atmospheric stability that allow for the build-up of (222)Rn and (220)Rn progeny. Similar increases in gamma-radiation dose have been measured at a nearby monitoring station situated approximately 11 miles from Aldermaston. Increases in gamma-radiation dose during heavy rainfall have also been observed throughout the UK, that followed the trajectory of an air mass. All events decreased to typical values within 1-2 h as the water permeated into the ground below and the radioactivity decayed away. PMID:20826890

  5. Luffa fibers and gamma radiation as improvement tools of polymer Gonzalo Martnez-Barrera a,

    E-print Network

    North Texas, University of

    [3,4]. The mix design of polymer concrete involves an aggregate size gradation to provide the lowestLuffa fibers and gamma radiation as improvement tools of polymer concrete Gonzalo Martínez-5017, USA h i g h l i g h t s Polymer concrete with silicious sand, unsaturated polyester resin and luffa

  6. Radiation-induced epilation due to couch transit dose for the Leksell Gamma Knife model C

    Microsoft Academic Search

    Carla D Bradford; Brian Morabito; Douglas R Shearer; Georg Norén; Prakash Chougule

    2002-01-01

    Purpose: To determine the cause of epilation at the top of the head for 2 patients with acoustic neuromas after undergoing fractionated radiosurgery with the Leskell Gamma Knife model C. This epilation was unexpected, because the treatment planning program stated the dose at this location was <0.1 Gy.Methods and Materials: The radiation dose along a central axis, parallel to the

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  8. Investigation of feasibility of using mexamine for postradiation protection of L cells. [Gamma radiation

    Microsoft Academic Search

    S. N. Valter; Yu. F. Martynchik; A. G. Sverdlov

    1977-01-01

    Suspension of L cells were exposed to gamma radiation; mexamine was added before and after irradiation. Effects of caffeine on cells were also studied. Observations were made on survival time, colony formation, and chromosomal aberrations. When mexamine was administered before irradiation a protective effect was demonstrated, but when added after irradiation there was no protective effect. Caffeine did not have

  9. Degradation in Thermal Properties and Morphology of Polyetheretherketone-Alumina Composites Exposed to Gamma Radiation

    NASA Astrophysics Data System (ADS)

    Lawrence, Falix; Mishra, Satyabrata; Mallika, C.; Kamachi Mudali, U.; Natarajan, R.; Ponraju, D.; Seshadri, S. K.; Sampath Kumar, T. S.

    2012-07-01

    Sheets of polyetheretherketone (PEEK) and PEEK-alumina composites with micron-sized alumina powder with 5, 10, 15, 20, and 25% by weight were fabricated, irradiated with gamma rays up to 10 MGy and the degradation in their thermal properties and morphology were evaluated. The radicals generated during irradiation get stabilized by chain scission and crosslinking. Chain scission is predominant on the surface and crosslinking is predominant in the bulk of the samples. Owing to radiation damage, the glass transition temperature, T g increased for pure PEEK from 136 to 140.5 °C, whereas the shift in T g for the composites decreased with increase in alumina content and for PEEK-25% alumina, the change in T g was insignificant, as alumina acts as an excitation energy sink and reduces the crosslinking density, which in turn decreased the shift in T g towards higher temperature. Similarly, the melting temperature, T m and enthalpy of melting, ? H m of PEEK and PEEK-alumina composites decreased on account of radiation owing to the restriction of chain mobility and disordering of structures caused by crosslinks. The decrease in T m and ? H m was more pronounced in pure PEEK and the extent of decrease in T m and ? H m was less for composites. SEM images revealed the formation of micro-cracks and micro-pores in PEEK due to radiation. The SEM image of irradiated PEEK-alumina (25%) composite showed negligible micro-cracks and micro-pores, because of the reinforcing effect of high alumina content in the PEEK matrix which helps in reducing the degradation in the properties of the polymer. Though alumina reduces the degradation of the polymer matrix during irradiation, an optimum level of ceramic fillers only have to be loaded to the polymer to avoid the reduction in toughness.

  10. Radiation inactivation of human gamma-interferon: cellular activation requires two dimers.

    PubMed Central

    Langer, J A; Rashidbaigi, A; Garotta, G; Kempner, E

    1994-01-01

    gamma-Interferon (IFN-gamma) is a 17-kDa broad-spectrum cytokine which exerts its effects on a variety of target cells through its interaction with the IFN-gamma receptor. Although physicochemical studies of Escherichia coli-derived IFN-gamma, as well as its crystal structure, demonstrate that it is a homodimer in solution (M(r) 34,000), previous radiation inactivation studies yielded a functional size for IFN-gamma of 63-73 kDa in an antiviral assay. To understand the relationship between the solution form of IFN-gamma and the moiety that actually binds to the cellular receptor and activates cells, we examined irradiated nonradioactive and 32P-labeled IFN-gamma for its migration in SDS/polyacrylamide gels (to determine its physical integrity), its binding to cells, its reactivity in an ELISA, and its antiviral activity. The functional size of IFN-gamma differed in the assays, being 22 +/- 2 kDa for the physical destruction of IFN-gamma, 56 +/- 2 kDa for the cellular binding assay, 45-50 kDa for reactivity in the ELISA, and 72 +/- 6 kDa for antiviral activity. The results from the binding assays constitute direct evidence that IFN-gamma binds to its cellular receptor as a dimer. However, for antiviral activity, the functional mass is equivalent to a tetramer. This is consistent with models involving ligand-induced receptor dimerization, whereby two dimers acting in concert (equivalent to the target size of a tetramer) are required to activate cells in the antiviral assay. Images PMID:8016072

  11. Efficient modeling of compton diode gamma radiation detectors

    SciTech Connect

    Drumm, C.R.; Hohlfelder, J.J.; Kotulski, J.D.; Scrivner, G.L.; Mills, G.S.; Tanaka, T.J. (Sandia National Labs., Albuquerque, NM (United States))

    1992-08-01

    This paper reports on the CEPXS/ONELD code package which proves to be significantly more efficient than electron Monte Carlo for computing spherical Compton diode response to gamma irradiation, requiring only minutes instead of hours of Cray computer time. The adjoint capability of CEPXS/ONELD allows the complete energy-angle response of a Compton diode to be determined with a single transport calculation. The method is a useful tool for determining new Compton-diode designs with desired energy-response characteristics.

  12. Measurement of $e^+e^- \\to \\gamma\\chi_{cJ}$ via initial state radiation at Belle

    E-print Network

    Han, Y L; Yuan, C Z; Shen, C P; Wang, P; Abdesselam, A; Adachi, I; Aihara, H; Said, S Al; Asner, D M; Aushev, T; Babu, V; Badhrees, I; Bansal, V; Bhardwaj, V; Biswal, J; Bozek, A; Bra?ko, M; Chen, A; Cheon, B G; Chistov, R; Cho, K; Chobanova, V; Choi, S -K; Cinabro, D; Dalseno, J; Danilov, M; Doležal, Z; Drutskoy, A; Dutta, D; Eidelman, S; Farhat, H; Fast, J E; Ferber, T; Fulsom, B G; Gaur, V; Gabyshev, N; Garmash, A; Getzkow, D; Gillard, R; Glattauer, R; Goh, Y M; Goldenzweig, P; Golob, B; Haba, J; Hayasaka, K; Hayashii, H; He, X H; Horiguchi, T; Hou, W -S; Iijima, T; Ishikawa, A; Jaegle, I; Joffe, D; Joo, K K; Kichimi, H; Kim, D Y; Kim, J B; Kim, J H; Kim, K T; Kim, S H; Kim, Y J; Kinoshita, K; Ko, B R; Kodyš, P; Križan, P; Krokovny, P; Lewis, P; Gioi, L Li; Libby, J; Liventsev, D; Lukin, P; Masuda, M; Matvienko, D; Miyabayashi, K; Miyata, H; Mizuk, R; Moll, A; Moon, H K; Mussa, R; Nakano, E; Nakao, M; Nayak, M; Nisar, N K; Nishida, S; Ogawa, S; Okuno, S; Ostrowicz, W; Pakhlov, P; Pakhlova, G; Pal, B; Park, H; Pedlar, T K; Pestotnik, R; Petri?, M; Piilonen, L E; Pulvermacher, C; Ribežl, E; Ritter, M; Rostomyan, A; Sahoo, H; Sakai, Y; Sandilya, S; Santelj, L; Sanuki, T; Schneider, O; Schnell, G; Schwanda, C; Senyo, K; Sevior, M E; Shapkin, M; Shebalin, V; Shibata, T -A; Shiu, J -G; Shwartz, B; Simon, F; Sohn, Y -S; Sokolov, A; Solovieva, E; Stani?, S; Steder, M; Sumihama, M; Tamponi, U; Teramoto, Y; Uchida, M; Uehara, S; Uglov, T; Unno, Y; Uno, S; Usov, Y; Van Hulse, C; Vanhoefer, P; Varner, G; Vossen, A; Wagner, M N; Watanabe, Y; Williams, K M; Yashchenko, S; Yook, Y; Zhang, C C; Zhang, Z P; Zhilich, V; Zhulanov, V; Zupanc, A

    2015-01-01

    The process $e^+e^- \\to \\gamma\\chi_{cJ}$ ($J$=1, 2) is studied via initial state radiation using 980 fb$^{-1}$ of data at and around the $\\Upsilon(nS)$ ($n$=1, 2, 3, 4, 5) resonances collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. No significant signal is observed except from $\\psi(2S)$ decays. Upper limits on the cross sections between $\\sqrt{s}=3.80$ and $5.56~{\\rm GeV}$ are determined at the 90% credibility level, which range from few pb to a few tens of pb. We also set upper limits on the decay rate of the vector charmonium [$\\psi(4040$), $\\psi(4160)$, and $\\psi(4415)$] and charmoniumlike [$Y(4260)$, $Y(4360)$, and $Y(4660)$] states to $\\gamma\\chi_{cJ}$.

  13. Investigation of background radiation levels and geologic unit profiles in Durango, Colorado

    SciTech Connect

    Triplett, G.H. (Oak Ridge National Lab., TN (USA)); Foutz, W.L.; Lesperance, L.R. (Oak Ridge Associated Universities, Inc., TN (USA))

    1989-11-01

    As part of the Uranium Mill Tailings Remedial Action (UMTRA) Project, Oak Ridge National Laboratory (ORNL) has performed radiological surveys on 435 vicinity properties (VPs) in the Durango area. This study was undertaken to establish the background radiation levels and geologic unit profiles in the Durango VP area. During the months of May through June, 1986, extensive radiometric measurements and surface soil samples were collected in the Durango VP area by personnel from ORNL's Grand Junction Office. A majority of the Durango VP surveys were conducted at sites underlain by Quaternary alluvium, older Quaternary gravels, and Cretaceous Lewis and Mancos shales. These four geologic units were selected to be evaluated. The data indicated no formation anomalies and established regional background radiation levels. Durango background radionuclide concentrations in surface soil were determined to be 20.3 {plus minus} 3.4 pCi/g for {sup 40}K, 1.6 {plus minus} 0.5 pCi/g for {sup 226}Ra, and 1.2 {plus minus} 0.3 pCi/g for {sup 232}Th. The Durango background gamma exposure rate was found to be 16.5 {plus minus} 1.3 {mu}R/h. Average gamma spectral count rate measurements for {sup 40}K, {sup 226}Ra and {sup 232}Th were determined to be 553, 150, and 98 counts per minute (cpm), respectively. Geologic unit profiles and Durango background radiation measurements are presented and compared with other areas. 19 refs., 15 figs., 5 tabs.

  14. CARBON FIBRE COMPOSITE MATERIALS PRODUCED BY GAMMA RADIATION INDUCED CURING OF EPOXY RESINS

    SciTech Connect

    Dispenza, C.; Spadaro, G.; Alessi, S. [Dipartimento di Ingegneria Chimica dei Processi e dei Materiali (DICPM), Centro Interdipartimentale sui Materiali Compositi (CIRMAC), Universita di Palermo, Viale delle Scienze 90128, Palermo (Italy)

    2008-08-28

    It is well known that ionizing radiation can initiate polymerization of suitable monomers for many applications. In this work an epoxy difunctional monomer has been used as matrix of a carbon fibre composite in order to produce materials through gamma radiation, for aerospace and advanced automotive applications. Radiation curing has been performed at different absorbed doses and, as comparison, also thermal curing of the same monomer formulations has been done. Furthermore some irradiated samples have been also subjected to a post irradiation thermal curing in order to complete the polymerization reactions. The properties of the cured materials have been studied by moisture absorption isotherms, dynamic mechanical thermal analysis and mechanical flexural tests.

  15. Modification of silicone sealant to improve gamma radiation resistance, by addition of protective agents

    NASA Astrophysics Data System (ADS)

    González-Pérez, Giovanni; Burillo, Guillermina

    2013-09-01

    Poly (dimethylsiloxane) (PDMS) sealant (SS) was modified with the addition of different protective compounds to conserve its physical-chemical properties during gamma irradiation. 2-Vinyl naphthalene (2-VN), bisphenol-A (BPA) and poly (vinyl carbazole) (PVK) were used to evaluate radiation protection through the crosslinking effect of radiation. The samples were irradiated with doses from 100 kGy to 500 kGy at room temperature in air, with a 60Co gamma source, and the changes in molecular weight, thermal behavior, elastic properties and infrared spectra (FTIR-ATR) absorbance analysis were determined. The molecular weight of unmodified silicone sealant increases with the absorbed dose because of crosslinking as predominant effect. However, the crosslinking effect was inhibited with the addition of protective agent due to the aromatic compounds present. Modified silicone sealant films present better radiation resistance than unmodified system.

  16. 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.

  17. Favorable effect of gamma-radiation for in-stent restenosis: effect of diabetes on angiographic and clinical outcomes.

    PubMed

    Iakovou, Ioannis; Mehran, Roxana; Dangas, George; Lansky, Alexandra J; Stone, Gregg W; Mintz, Gary S; Aymong, Eve; Ashby, Dale T; Pichard, Augusto D; Satler, Lowell F; Kent, Kenneth; Leon, Martin B; Waksman, Ron

    2004-07-01

    The purpose of this study was to examine the effect of vascular brachytherapy with gamma-radiation (gamma-RT) in patients with diabetes mellitus (DM) with coronary in-stent restenosis (ISR). In the Washington Radiation for In-Stent Restenosis (WRIST) trial, 130 patients with ISR were treated with (192)Ir or placebo. Of the patients enrolled, 44 (34%) had DM (18 of them treated with gamma-RT and 26 with placebo). Gamma-radiation therapy of ISR in diabetics resulted in similar procedural success and in-hospital outcome compared to nondiabetics. At 6-month follow-up, both DM and non-DM patients treated with gamma-RT had significantly lower target lesion revascularization (TLR), target vessel revascularization, and major adverse cardiac event rates compared to placebo. DM remains a powerful predictor of TLR and major adverse cardiac events even after treatment of ISR with gamma-RT. PMID:15224295

  18. Crosslinking of polyol(allylcarbonates) by gamma radiation

    NASA Astrophysics Data System (ADS)

    Delia López, V.; Esparza, Rosalío; Burillo, Guillermina

    1995-04-01

    Polyolallylcarbonate networks were synthesized in a vacuum at room temperature, with gamma irradiation, in a quiescent radical crosslinking polymerization. The polyfunctional monomers studied here were: diallylcarbonate (DAC), monoethylene glycol bis-allylcarbonate (MEGBAC), propylene glycol bis-allylcarbonate (PGBAC), dipropylene glycol bis-allylcarbonate (DPGBAC) and tris-allylcarbonate of glycerol (TACG). The results of the sol-gel analysis of irradiated monomers and characterization by IR, elemental analysis and GPC of different extracted fractions were that polyol(allylcarbonate of crosslinking via their ?-bonds (allylic group). The gelation doses are a function of the monomer reactivities, and of the monomer's chemical composition. TACG was the most reactive, while DAC crosslinked at the highest irradiation doses.

  19. (Gamma scattering in condensed matter with high intensity Moessbauer radiation)

    SciTech Connect

    Not Available

    1989-01-01

    There are four areas where major progress has occurred this year. We have applied the Fourier-transform method of describing and analyzing Moessbauer effect (ME) line shapes to make measurements of the temperature dependence of the recoilless fraction in tungsten. We have carried out quasi-elastic measurements of the gamma scattering from viscous liquids, learning about diffusive motion in polydimethylsiloxane, pentadecane, and glycerol. We have made major progress in fundamental physics, having shown for the first time how to determine precise quantum interference parameters, obtaining experimental results on the 46.5 keV line of {sup 183}W and the 129 keV line of {sup 191}Ir. Finally, we have continued our development of MICE detectors, with a theoretical analysis of the MICE lineshape and its relation to the lineshape of conventional transmission ME spectroscopy. 12 refs.

  20. Radiation-induced bystander effects in the Atlantic salmon (salmo salar L.) following mixed exposure to copper and aluminum combined with low-dose gamma radiation.

    PubMed

    Mothersill, Carmel; Smith, Richard W; Heier, Lene Sørlie; Teien, Hans-Christian; Lind, Ole Christian; Land, Ole Christian; Seymour, Colin B; Oughton, Deborah; Salbu, Brit

    2014-03-01

    Very little is known about the combined effects of low doses of heavy metals and radiation. However, such "multiple stressor" exposure is the reality in the environment. In the work reported in this paper, fish were exposed to cobalt 60 gamma irradiation with or without copper or aluminum in the water. Doses of radiation ranged from 4 to 75 mGy delivered over 48 or 6 h. Copper doses ranged from 10 to 80 ?g/L for the same time period. The aluminum dose was 250 ?g/L. Gills and skin were removed from the fish after exposure and explanted in tissue culture flasks for investigation of bystander effects of the exposures using a stress signal reporter assay, which has been demonstrated to be a sensitive indicator of homeostatic perturbations in cells. The results show complex synergistic interactions of radiation and copper. Gills on the whole produce more toxic bystander signals than skin, but the additivity scores show highly variable results which depend on dose and time of exposure. The impacts of low doses of copper and low doses of radiation are greater than additive, medium levels of copper alone have a similar level of effect of bystander signal toxicity to the low dose. The addition of radiation stress, however, produces clear protective effects in the reporters treated with skin-derived medium. Gill-derived medium from the same fish did not show protective effects. Radiation exposure in the presence of 80 ?g/L led to highly variable results, which due to animal variation were not significantly different from the effect of copper alone. The results are stressor type, stressor concentration and time dependent. Clearly co-exposure to radiation and heavy metals does not always lead to simple additive effects. PMID:24352529

  1. Evaluation of fungal burden and aflatoxin presence in packed medicinal plants treated by gamma radiation.

    PubMed

    Aquino, Simone; Gonçalez, Edlayne; Rossi, Maria Helena; Nogueira, Juliana Hellmeister de Campos; Reis, Tatiana Alves Dos; Corrêa, Benedito

    2010-05-01

    This study was developed to evaluate the fungal burden, toxigenic molds, and mycotoxin contamination and to verify the effects of gamma radiation in four kinds of medicinal plants stored before and after 30 days of irradiation treatment. Eighty samples of medicinal plants (Peumus boldus, Camellia sinensis, Maytenus ilicifolia, and Cassia angustifolia) purchased from drugstores, wholesale, and open-air markets in São Paulo city, Brazil, were analyzed. The samples were treated using a (60)Co gamma ray source (Gammacell) with doses of 5 and 10 kGy. Nonirradiated samples were used as controls of fungal isolates. For enumeration of fungi on medicinal plants, serial dilutions of the samples were plated in duplicate onto dichloran 18% glycerol agar. The control samples revealed a high burden of molds, including toxigenic fungi. The process of gamma radiation was effective in reducing the number of CFU per gram in all irradiated samples of medicinal plants after 30 days of storage, using a dose of 10 kGy and maintaining samples in a protective package. No aflatoxins were detected. Gamma radiation treatment can be used as an effective method for preventing fungal deterioration of medicinal plants subject to long-term storage. PMID:20501045

  2. Effects of gamma radiation on codling moth, Cydia pomonella (L.), eggs

    NASA Astrophysics Data System (ADS)

    Mansour, M.; Mohamad, F.

    2004-12-01

    The radiosensitivity of codling moth, Cydia pomonella (L.), eggs in different stages of development was studied. Eggs ranging in age from 1-24 to 97-120 h were exposed, at 24 h intervals, to gamma radiation doses ranging from 10 to 350 Gy. The effects of gamma radiation on egg hatch, pupation and adult emergence was examined. Results showed that the radiosensitivity of codling moth eggs decreased with increasing age. Egg hatch in 1-24 h old eggs was significantly affected at 20 Gy dose and at 60 Gy dose, egg hatch decreased to about 1%. At the age of 25-48 h, however, egg hatch at 60 Gy dose was about 10%, and egg sensitivity to gamma irradiation decreased significantly in the 49-72 h age group; 60 Gy dose had no significant effect on egg hatch. Eggs irradiated few hours before hatch (at the blackhead stage), were the most resistant ones; 100 Gy had no significant effect on egg hatch and at 350 Gy dose over 56% of the eggs hatched. When adult emergence was used as a criterion for measuring effectiveness, however, the effect of gamma radiation was very sever. A dose of 60 Gy completely prevented adult emergence and at 100 Gy dose all resulted larvae died before pupation.

  3. Nonthermal Radiation of Cosmological Gamma-Ray Bursters

    NASA Astrophysics Data System (ADS)

    Smolsky, M. V.; Usov, V. V.

    2000-03-01

    We use 1.5 dimensional particle-in-cell plasma simulations to study the interaction of a relativistic, strongly magnetized wind with an ambient medium. Such an interaction is a plausible mechanism that leads to generation of cosmological ?-ray bursts. We confirm the idea of Mészáros & Rees that an essential part (about 20%) of the energy that is lost by the wind in the process of its deceleration may be transferred to high-energy electrons and then to high-frequency (X-ray and ?-ray) emission. We show that in the wind frame the spectrum of electrons that are accelerated at the wind front and move ahead of the front is nearly a two-dimensional relativistic Maxwellian with a relativistic temperature T=mec2?T/k~=6x109?T K, where ?T is equal to 200?0, with the accuracy of ~20%, and ?0 is the Lorentz factor of the wind, ?0>~102 for winds outflowing from cosmological ?-ray bursters. Our simulations point to an existence of a high-energy tail of accelerated electrons with a Lorentz factor of more than ~700?0. Large-amplitude electromagnetic waves are generated by the oscillating currents at the wind front. The mean field of these waves ahead of the wind front is an order of magnitude less than the magnetic field of the wind. High-energy electrons that are accelerated at the wind front and injected into the region ahead of the front generate synchro-Compton radiation in the fields of large-amplitude electromagnetic waves. This radiation closely resembles synchrotron radiation and can reproduce the nonthermal radiation of ?-ray bursts observed in the Ginga and BATSE ranges (from a few keV to a few MeV). Synchrotron photons that are generated in the vicinity of the wind front may be responsible for the radiation of ?-ray bursts in the EGRET energy range above a few ten MeV. The spectrum of ?-ray bursts in high-energy ?-rays may extend, in principle, up to the maximum energy of the accelerated electrons, which is about 1013(?0/102)2 eV in the frame of the ?-ray burster.

  4. 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.

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

    DOEpatents

    Chiles, Marion M. (Knoxville, TN); Mihalczo, John T. (Oak Ridge, TN); Blakeman, Edward D. (Oak Ridge, TN)

    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.

  6. 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.

  7. Interactions between endothelial cells and T cells modulate responses to mixed neutron/gamma radiation.

    PubMed

    Cary, Lynnette H; Noutai, Daniel; Salber, Rudolph E; Williams, Margaret S; Ngudiankama, Barbara F; Whitnall, Mark H

    2014-06-01

    Detonation of an improvised nuclear device near a population center would cause significant casualties from the acute radiation syndrome (ARS) due to exposure to mixed neutron/gamma fields (MF). The pathophysiology of ARS involves inflammation, microvascular damage and alterations in immune function. Interactions between endothelial cells (EC) and hematopoietic cells are important not only for regulating immune cell traffic and function, but also for providing the microenvironment that controls survival, differentiation and migration of hematopoietic stem and progenitor cells in blood-forming tissues. Endothelial cells/leukocyte interactions also influence tumor progression and the results of anticancer therapies. In this study, we hypothesized that irradiation of endothelial cells would modulate their effects on hematopoietic cells and vice versa. Human umbilical vein endothelial cells (HUVEC) and immortalized T lymphocytes (Jurkat cells) were cultured individually and in co-culture after exposure to mixed fields. Effects of nonirradiated cells were compared to effects of irradiated cells and alterations in signaling pathways were determined. Mitogen-activated protein kinases (MAPKs) p38 and p44/42 (ERK1/2) in HUVEC exhibited higher levels of phosphorylated protein after exposure to mixed field radiation. IL-6, IL-8, G-CSF, platelet derived growth factor (PDGF) and angiopoietin 2 (ANG2) protein expression were upregulated in HUVEC by exposure to mixed field radiation. PCR arrays using HUVEC mRNA revealed alterations in gene expression after exposure to mixed fields and/or co-culture with Jurkat cells. The presence of HUVEC also influenced the function of Jurkat cells. Nonirradiated Jurkat cells showed an increase in proliferation when co-cultured with nonirradiated HUVEC, and a decrease in proliferation when co-cultured with irradiated HUVEC. Additionally, nonirradiated Jurkat cells incubated in media from irradiated HUVEC exhibited upregulation of activated caspase 3. Irradiation of Jurkat cells caused a G2/M arrest and increased adherence to HUVEC. When co-cultured with HUVEC, irradiated Jurkat cells exhibited G0/G1 arrest and increased apoptosis. The data indicate that gene expression and cell function of endothelial cells and hematopoietic cells are influenced by radiation and by interactions between the two cell types. These phenomena may affect the success of therapies for ARS and cancer. PMID:24828109

  8. Shield optimization program: Part 4, Effects of neutron and gamma-ray radiations from nuclear weapons on SDI weapon platforms

    SciTech Connect

    Smith, M.S.; Johsnon, J.O.; Gabriel, T.A.; Barnes, J.M.; Drischler, J.D.; Santoro, R.T.

    1989-03-01

    Initial studies have been completed to estimate the radiation induced damage in silicon based electronic components onboard a representative Space Based Interceptor (SBI) weapon platform. The SBI weapon platform model used in the studies represents the author's concept of such a system. The analysis was completed for neutrons and gamma rays emanating from a nuclear weapon detonation in space. Results indicate dose levels to the sensitive components within the SBI weapon platform may exceed design limits if the weapon is detonated within a critical radius. For example, a 1962 Starfish detonation at a distance of 91.4 km from the SBI weapon platform generates a total dose in the central instrument bay of 964 rads(Si). The dose rate, /dot /gamma//, assuming a 40 nsec deposition time, is 1 /times/ 10/sup 10/ rads(Si)/sec. All of the calculations were carried out for an unshielded SBI weapon platform to determine the radiation levels for which shielding must be designed to ensure survivability of the electronic systems. 10 refs., 7 figs., 13 tabs.

  9. Inexpensive Gamma Detector

    Microsoft Academic Search

    Donald R. Cone; David W. Garbellano

    1954-01-01

    A simple and inexpensive radiation detection device has been constructed sensitive to gamma fluxes in the range from a few to a few hundred roentgen per hour. Thus one can distinguish between dangerous and relatively safe radiation levels such as one might expect from radiological warfare, low level atomic blasts, or from ``rigged'' hydrogen bomb explosions.A typical device consists of

  10. Effect of gamma radiation on the structural and optical properties of Polyethyleneterephthalate (PET) polymer

    NASA Astrophysics Data System (ADS)

    Siddhartha; Aarya, Suveda; Dev, Kapil; Raghuvanshi, Suresh Kumar; Krishna, J. B. M.; Wahab, M. A.

    2012-04-01

    Effect of 1.25 MeV gamma radiation on the structural and optical properties of virgin and gamma irradiated (0-2000 kGy) Polyethyleneterephthalate (PET) polymer samples are analyzed using powder X-ray diffractometer and UV-vis spectrophotometer. Diffraction pattern of PET polymer indicates the semi-crystalline in nature whereas the crystallinity increases with increasing dose of irradiation. The remarkable variation in crystallite size is also observed. The absorption and activation energy increase and the optical band gap (Eg) decreases with increasing dose in UV-vis studies. The existence of the maximum absorption, their shifting and broadening due to gamma irradiation in PET polymer are also discussed.

  11. Radiation Protection by Cysteamine and Cellular Sulphydryl Levels

    Microsoft Academic Search

    László Révész; Helena Bergstrand

    1963-01-01

    IN publications describing a series of experiments a group of Dutch investigators1 recently gave quantitative results on the radioprotective power of different chemical agents at the cellular level in an in vitro system. Assayed by the degree to which radiation damage, as measured by the loss of reproductive integrity of human kidney cells, was prevented, it was shown that the

  12. The effects of radiative transfer on low-level cyclogenesis

    SciTech Connect

    Leach, M.J.; Raman, S. [North Carolina State Univ., Raleigh, NC (United States)

    1995-04-01

    Many investigators have documented the role that thermodynamic forcing due to radiative flux divergence plays in the enhancement or generation of circulation. Most of these studies involve large-scale systems, small-scale systems such as thunderstorms, and squall lines. The generation of circulation on large scales results from the creation of divergence in the upper troposphere and the maintenance of low-level potentially unstable air, and the maintenance of baroclinicity throughout the atmosphere. On smaller scales, radiative flux divergence acts similarly. In the thunderstorms and squall lines, the radiative forcing acts as a pump, increasing the divergence at the top of the storm systems and increasing the updraft velocity and the intensity of inflow at mid-levels in the storm systems. Other researchers have examined the role of surface processes and low-level baroclinicity in east coast cyclogenesis. In this paper, we examine the interactive role that radiative flux divergence, clouds, and surface processes play in low-level cyclogenesis and the creation or maintenance of the boundary layer baroclinicity.

  13. The Contribution of Tissue Level Organization to Genomic Stability Following Low Dose/Low Dose Rate Gamma and Proton Irradiation

    SciTech Connect

    Cheryl G. Burrell, Ph.D.

    2012-05-14

    The formation of functional tissue units is necessary in maintaining homeostasis within living systems, with individual cells contributing to these functional units through their three-dimensional organization with integrin and adhesion proteins to form a complex extra-cellular matrix (ECM). This is of particular importance in those tissues susceptible to radiation-induced tumor formation, such as epithelial glands. The assembly of epithelial cells of the thyroid is critical to their normal receipt of, and response to, incoming signals. Traditional tissue culture and live animals present significant challenges to radiation exposure and continuous sampling, however, the production of bioreactor-engineered tissues aims to bridge this gap by improve capabilities in continuous sampling from the same functional tissue, thereby increasing the ability to extrapolate changes induced by radiation to animals and humans in vivo. Our study proposes that the level of tissue organization will affect the induction and persistence of low dose radiation-induced genomic instability. Rat thyroid cells, grown in vitro as 3D tissue analogs in bioreactors and as 2D flask grown cultures were exposed to acute low dose (1, 5, 10 and 200 cGy) gamma rays. To assess immediate (6 hours) and delayed (up to 30 days) responses post-irradiation, various biological endpoints were studied including cytogenetic analyses, apoptosis analysis and cell viability/cytotoxicity analyses. Data assessing caspase 3/7 activity levels show that, this activity varies with time post radiation and that, overall, 3D cultures display more genomic instability (as shown by the lower levels of apoptosis over time) when compared to the 2D cultures. Variation in cell viability levels were only observed at the intermediate and late time points post radiation. Extensive analysis of chromosomal aberrations will give further insight on the whether the level of tissue organization influences genomic instability patterns after low dose radiation exposure. Cells viability/cytotoxicity analysis data are currently being analyzed to determine how these endpoints are affected under our experimental conditions. The results from this study will be translatable to risk assessment for assigning limits to radiation workers, pre-dosing for more effective radiotherapy and the consequences of long duration space flight. The data from this study has been presented a various scientific meetings/workshops and a manuscript, containing the findings, is currently being prepared for publication. Due to unforeseen challenges in collecting the data and standardizing experimental procedures, the second and third aims have not been completed. However, attempts will be made, based on the availability of funds, to continue this project so that these aims can be satisfied.

  14. Beta decay radiation signature from neutron-rich gamma-ray bursts?

    E-print Network

    Soebur Razzaque; Peter Meszaros

    2006-06-09

    Core collapse of massive stars and binary neutron stars or black hole-neutron star binary mergers are likely progenitors of long and short duration gamma-ray bursts respectively. Neutronized material in the former and neutron star material in the latter are ejected by the central engine implying a neutron-rich jet outflow. A free neutron, however, beta decays to a proton, an electron (beta) and an anti-neutrino in about fifteen minutes in its rest frame. Sudden creation of a relativistic electron is accompanied by radiation with unique temporal and spectral signature. We calculate here this radiation signature collectively emitted by all beta decay electrons from neutron-rich outflow. Detection of this signature may thus provide strong evidence for not only neutron but also for proton content in the relativistic gamma-ray burst jets.

  15. A New Natural Gamma Radiation Measurement System for Marine Sediment and Rock Analysis

    E-print Network

    Vasiliev, M A; Chubarian, G; Olsen, R; Bennight, C; Cobine, T; Fackler, D; Hastedt, M; Houpt, D; Mateo, Z; Vasilieva, Y B

    2010-01-01

    A new high-efficiency and low-background system for the measurement of natural gamma radioactivity in marine sediment and rock cores retrieved from beneath the seabed was designed, built, and installed on the JOIDES Resolution research vessel. The system includes eight large NaI(Tl) detectors that measure adjacent intervals of the core simultaneously, maximizing counting times and minimizing statistical error for the limited measurement times available during drilling expeditions. Effect to background ratio is maximized with passive lead shielding, including both ordinary and low-activity lead. Large-area plastic scintillator active shielding filters background associated with the high-energy part of cosmic radiation. The new system has at least an order of magnitude higher statistical reliability and significantly enhances data quality compared to other offshore natural gamma radiation (NGR) systems designed to measure geological core samples. Reliable correlations and interpretations of cored intervals are ...

  16. A new natural gamma radiation measurement system for marine sediment and rock analysis

    NASA Astrophysics Data System (ADS)

    Vasiliev, M. A.; Blum, P.; Chubarian, G.; Olsen, R.; Bennight, C.; Cobine, T.; Fackler, D.; Hastedt, M.; Houpt, D.; Mateo, Z.; Vasilieva, Y. B.

    2011-11-01

    A new high-efficiency and low-background system for the measurement of natural gamma radioactivity in marine sediment and rock cores retrieved from beneath the seabed was designed, built, and installed on the JOIDES Resolution research vessel. The system includes eight large NaI(Tl) detectors that measure adjacent intervals of the core simultaneously, maximizing counting times and minimizing statistical error for the limited measurement times available during drilling expeditions. Effect to background ratio is maximized with passive lead shielding, including both ordinary and low-activity lead. Large-area plastic scintillator active shielding filters background associated with the high-energy part of cosmic radiation. The new system has at least an order of magnitude higher statistical reliability and significantly enhances data quality compared to other offshore natural gamma radiation (NGR) systems designed to measure geological core samples. Reliable correlations and interpretations of cored intervals are possible at rates of a few counts per second.

  17. Operation of Bidirectional Switches (DIAC) and Silicon Controlled Rectifiers (SCR) in Gamma-Radiation Environment

    SciTech Connect

    Swidan, A.M.; El-Ghanam, S.M. [Women's College for Art, Science and Education, Ain- Shams University, Helioplis, Cairo (Egypt); Soliman, F.A.S. [Nuclear Materials Authority, P.O. Box 2404, Horrya-11361, Heliopolis, Cairo (Egypt)

    2005-03-17

    Gamma-irradiation effects on the electrical parameters of the Diode AC switch (DIAC; PHI37 500) and Silicon Controlled Rectifier (SCR; 2N4444) devices have been studied in detail, where gamma-dose up to 137 x 106 rad was found to cause a serious permanent damage on their electrical characteristics. A pronounced increase in the break-over voltage (from 31.5 to 35 V), holding-current (from 13 to 53 mA) and holding voltage (from 22 to 32 V) of the DIAC is noticed. Besides, a severe decrease in the dynamic break-over voltage range (from 10 to 2.5 V) and negative resistance (from -750 to -168 ohm) is also observed. Exposing the SCRs to gamma-radiation causes their turn-on voltage and forward voltage drop values to increase from 0.8 to 2.8 V and from 1.4 to 4.5 V, respectively. Additionally, the holding current increases to 18 mA although its initial value is 3.5 mA. For the two devices, the linear dependence and high sensitivity of their electrical parameters to gamma-dose suggest the application of such devices in the field of radiation dosimetry.

  18. Method for detecting water equivalent of snow using secondary cosmic gamma radiation

    DOEpatents

    Condreva, K.J.

    1997-01-14

    Water equivalent of accumulated snow determination by measurement of secondary background cosmic radiation attenuation by the snowpack. By measuring the attenuation of 3-10 MeV secondary gamma radiation it is possible to determine the water equivalent of snowpack. The apparatus is designed to operate remotely to determine the water equivalent of snow in areas which are difficult or hazardous to access during winter, accumulate the data as a function of time and transmit, by means of an associated telemetry system, the accumulated data back to a central data collection point for analysis. The electronic circuitry is designed so that a battery pack can be used to supply power. 4 figs.

  19. Method for detecting water equivalent of snow using secondary cosmic gamma radiation

    DOEpatents

    Condreva, Kenneth J. (1420 Fifth St., Livermore, Alameda County, CA 94550)

    1997-01-01

    Water equivalent of accumulated snow determination by measurement of secondary background cosmic radiation attenuation by the snowpack. By measuring the attentuation of 3-10 MeV secondary gamma radiation it is possible to determine the water equivalent of snowpack. The apparatus is designed to operate remotely to determine the water equivalent of snow in areas which are difficult or hazardous to access during winter, accumulate the data as a function of time and transmit, by means of an associated telemetry system, the accumulated data back to a central data collection point for analysis. The electronic circuitry is designed so that a battery pack can be used to supply power.

  20. Studies in feed spoilage: prevention of spoilage in ground corn by gamma radiation 

    E-print Network

    Webb, Billy Dean

    1959-01-01

    mold respiration on whole wheat which had been exposed to doses of gamma radiation between 2, 5 6 x 10 and 3. 75 x 10 rep. ghent containing 12 and 20 percent moisture was irradiated and that which had been irradiated with 12 percent moisture... was adjusted to 20 percent moisture before respiration of the two samples was compared. There was no difference in the dose range (between 125, 000 and 625, 000 rep) required to eliminate mold respiration in wheat that was ir- radiated at the two moisture...

  1. 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.

  2. Comparison of radiation damage in lead tungstate crystals under pion and gamma irradiation

    SciTech Connect

    Batarin, V.A.; Butler, J.; Davidenko, A.M.; Derevschikov, A.A.; Goncharenko, Y.M.; Grishin, V.N.; Kachanov, V.A.; Khodyrev, V.Y.; Konstantinov, A.S.; Kravtsov, V.I.; Kubota, Y.; Lukanin, V.S.; Matulenko, Y.A.; Melnick, Y.M.; Meschanin, A.P.; Mikhalin, N.E.; Minaev, N.G.; Mochalov, V.V.; Morozov, D.A.; Nogach, L.V.; Ryazantsev, A.V.; /Serpukhov,

    2003-12-01

    Studies of the radiation hardness of lead tungstate crystals produced by the Bogoroditsk Techno-Chemical Plant in Russia and the Shanghai Institute of Ceramics in China have been carried out at IHEP, Protvino. The crystals were irradiated by a 40 GeV pion beam. After full recovery, the same crystals were irradiated using a {sup 137}Cs {gamma}-ray source. The dose rate profiles along the crystal length were observed to be quite similar. We compare the effects of the two types of radiation on the crystals light output.

  3. Inactivation of human immunodeficiency virus by gamma radiation and its effect on plasma and coagulation factors

    SciTech Connect

    Hiemstra, H.; Tersmette, M.; Vos, A.H.; Over, J.; van Berkel, M.P.; de Bree, H. (Central Laboratory of The Netherlands, Red Cross Blood Transfusion Service, Amsterdam (Netherlands))

    1991-01-01

    The inactivation of HIV by gamma-radiation was studied in frozen and liquid plasma; a reduction of the virus titer of 5 to 6 logs was achieved at doses of 5 to 10 Mrad at -80 degrees C and 2.5 Mrad at 15 degrees C. The effect of irradiation on the biologic activity of a number of coagulation factors in plasma and in lyophilized concentrates of factor VIII (FVIII) and prothrombin complex was examined. A recovery of 85 percent of the biologic activity of therapeutic components present in frozen plasma and in lyophilized coagulation factor concentrates was reached at radiation doses as low as 1.5 and 0.5 Mrad, respectively. As derived from the first-order radiation inactivation curves, the radiosensitive target size of HIV was estimated to be 1 to 3 MDa; the target size of FVIII was estimated to be 130 to 160 kDa. Gamma radiation must be disregarded as a method for the sterilization of plasma and plasma-derived products, because of the low reduction of virus infectivity at radiation doses that still give acceptable recovery of biologic activity of plasma components.

  4. Durability and shielding performance of borated Ceramicrete coatings in beta and gamma radiation fields

    NASA Astrophysics Data System (ADS)

    Wagh, Arun S.; Sayenko, S. Yu.; Dovbnya, A. N.; Shkuropatenko, V. A.; Tarasov, R. V.; Rybka, A. V.; Zakharchenko, A. A.

    2015-07-01

    Ceramicrete™, a chemically bonded phosphate ceramic, was developed for nuclear waste immobilization and nuclear radiation shielding. Ceramicrete products are fabricated by an acid-base reaction between magnesium oxide and mono potassium phosphate. Fillers are used to impart desired properties to the product. Ceramicrete's tailored compositions have resulted in several commercial structural products, including corrosion- and fire-protection coatings. Their borated version, called Borobond™, has been studied for its neutron shielding capabilities and is being used in structures built for storage of nuclear materials. This investigation assesses the durability and shielding performance of borated Ceramicrete coatings when exposed to gamma and beta radiations to predict the composition needed for optimal shielding performance in a realistic nuclear radiation field. Investigations were conducted using experimental data coupled with predictive Monte Carlo computer model. The results show that it is possible to produce products for simultaneous shielding of all three types of nuclear radiations, viz., neutrons, gamma-, and beta-rays. Additionally, because sprayable Ceramicrete coatings exhibit excellent corrosion- and fire-protection characteristics on steel, this research also establishes an opportunity to produce thick coatings to enhance the shielding performance of corrosion and fire protection coatings for use in high radiation environment in nuclear industry.

  5. [gamma]-radiation-induced changes in the chemical and physical structure of poly(ethylene terephthalate)

    Microsoft Academic Search

    Jin; Ho-Seon

    1992-01-01

    Poly(ethylene terephthalate) (PET) film was irradiated with [gamma]-rays in air at doses from 0 to 620 Mrad, and at the rate of 0l8 to 1.0 Mrad\\/hr. Radiation-induced physical structure changes were studied by DMA and DSC measurements. Tensile properties were measured to find interrelationships with chemical and physical structure changes. Below 100 Mrad, PET shows little change in NMR and

  6. Search for Bremsstrahlung radiation in quasi-free n p --> n p gamma reactions

    Microsoft Academic Search

    J. Przerwa; H.-H. Adam; A. Budzanowski; R. Czyzykiewicz; D. Grzonka; M. Janusz; L. Jarczyk; B. Kamys; A. Khoukaz; K. Kilian; P. Klaja; N. Lang; P. Moskal; W. Oelert; C. Piskor-Ignatowicz; T. Rozek; R. Santo; T. Sefzick; M. Siemaszko; J. Smyrski; A. Taeschner; P. Winter; M. Wolke; P. Wuestner; W. Zipper

    2004-01-01

    Due to the high sensitivity of the N N --> N N gamma reaction to the\\u000anucleon-nucleon potential, Bremsstrahlung radiation is used as a tool to\\u000ainvestigate details of the nucleon-nucleon interaction. Such investigations can\\u000abe performed at the cooler synchrotron COSY in the Research Centre Juelich, by\\u000adint of the COSY-11 detection system. The results of the identification of

  7. Gamma ray bursts may be blueshifted bundles of the relic radiation

    E-print Network

    Krasi?ski, Andrzej

    2015-01-01

    A hypothesis is proposed that the gamma-ray bursts (GRBs) may arise by blueshifting the emission radiation of hydrogen and helium generated during the last scattering epoch. The blueshift mechanism is provided by such a Lema\\^{\\i}tre -- Tolman (L--T) model, in which the bang-time function $t_B(r)$ is not everywhere constant. Blueshift arises on \\textit{radial} rays that are emitted over regions where $\\dril{t_B} r \

  8. Effects of Solvent on Gamma Radiation–Induced Graft Copolymerization of Acrylamide onto Poly (3-hydroxybutyrate)

    Microsoft Academic Search

    Maykel González-Torres; Arllene M. Perez-González; Manuel González-Perez; César Santiago-Tepantlán; Silvia G. Solís-Rosales; Aurelio H. Heredia-Jiménez

    2011-01-01

    In the present article the gamma radiation–induced graft copolymerization of acrylamide (AAm) onto poly (3-hydroxybutyrate) (PHB) has been carried out by the simultaneous irradiation method. The effect of different solvents on the graft reaction was investigated. The P(HB-g-AAm) thus synthesized were characterized by Fourier transform-infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron micrography (SEM), swelling behavior,

  9. The Gamma Radiation from the Reaction D(p,?)3He

    Microsoft Academic Search

    G M Griffiths; J B Warren

    1955-01-01

    Using a scintillation counter for the measurement of the gamma radiation, the Q value of the reaction D(p,?)3He was found to be 5.50±0.03 MeV. The Doppler shift has been measured. The angular distribution was found to be nearly a pure sin2? pattern at all proton bombarding energies from 0.5 to 2 MeV but evidence has been obtained for a small

  10. Reconciling observed gamma-ray burst prompt spectra with synchrotron radiation?

    Microsoft Academic Search

    F. Daigne; Z. Bosnjak; G. Dubus

    2011-01-01

    Context. Gamma-ray burst emission in the prompt phase is often interpreted as synchrotron radiation from high-energy electrons accelerated in internal shocks. Fast synchrotron cooling of a power-law distribution of electrons leads to the prediction that the slope below the spectral peak has a photon index alpha = -3\\/2 (N(E) ? Ealpha). However, this differs significantly from the observed median value

  11. Deinococcus radiotolerans sp. nov., a gamma-radiation-resistant bacterium isolated from gamma ray-irradiated soil.

    PubMed

    Cha, Seho; Srinivasan, Sathiyaraj; Seo, Taegun; Kim, Myung Kyum

    2014-01-01

    Two gamma-radiation-resistant bacterial strains, designated C1(T) and C2, were isolated from a soil sample collected at Jeongeup-Si, South Korea. These strains were observed to be Gram-negative, non-motile, rod-shaped, and to form pink colonies. Phylogenetic analysis based on 16S rRNA gene sequences revealed that these strains belong to the genus Deinococcus in the family Deinococcaceae. Strains C1(T) and C2 have the highest sequence similarities with Deinococcus daejeonensis MJ27(T) (97.56 %) and Deinococcus grandis DSM 39663(T) (97.50 %). Like other members of the genus Deinococcus, the novel isolates showed resistance to gamma-radiation with a D10 value in excess of 8 kGy. The isolates were found to have menaquinone MK-8 as the predominant respiratory quinone and an unidentified phosphoglycolipid as major polar lipid. In addition, the most abundant fatty acids of strain C1(T) were identified as C15:1 ?6c (25.5 %), C16:1 ?7c (18.7 %) and C15:0 (9.7 %). Genomic analysis results showed that the DNA G+C contents of strain C1(T) and C2 are 68.59 and 68.57 %, respectively. Taken together, the polyphasic taxonomic data support the proposal that the isolates C1(T) and C2 represent a novel species of the genus Deinococcus, for which the name Deinococcus radiotolerans sp. nov. is proposed. The type strain is a strain C1(T) (=KCTC 33150(T) = JCM 19173(T)). PMID:24190343

  12. GammaRadiation Damage in Epitaxial Gallium Arsenide

    Microsoft Academic Search

    G. E. Brehmt; G. L. Pearson

    1972-01-01

    Electrical and photoluminescence measurements were carried out on liquid epitaxial GaAs single crystals after irradiation at room temperature by 1.25-MeV 60Co ? rays. Following each of a series of irradiations, Hall measurements were made on both n- and p-type crystals as a function of temperature between 77 and 300°K. The n-type crystals exhibited energy levels 0.13, 0.16, and 0.30 eV

  13. 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

  14. 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.

  15. Branching Fractions and CP-Violating Asymmetries in Radiative B Decays to eta K gamma

    SciTech Connect

    Aubert, B.

    2008-05-14

    The authors present measurements of the CP-violation parameters S and C for the radiative decay B{sup 0} {yields} {eta}K{sub S}{sup 0}{gamma}; for B {yields} {eta}K{gamma} they also measure the branching fractions and for B{sup +} {yields} {eta}K{sup +}{gamma} the time-integrated charge asymmetry {Alpha}{sub ch}. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 465 x 10{sup 6} B{bar B} pairs produced in e{sup +}e{sup -} annihilation. The results are S = -0.18{sub -0.46}{sup +0.49} {+-} 0.12, C = -0.32{sub -0.39}{sup +0.40} {+-} 0.07, {Beta}(B{sup 0} {yields} {eta}K{sup 0}{gamma}) = (7.1{sub -2.0}{sup +2.1} {+-} 0.4) x 10{sup -6}, {Beta}(B{sup +} {yields} {eta}K{sup +}{gamma}) = (7.7 {+-} 1.0 {+-} 0.4) x 10{sup -6}, and {Alpha}{sub ch} = (-9.0{sub -9.8}{sup +10.4} {+-} 1.4) x 10{sup -2}. The first error quoted is statistical and the second systematic.

  16. Radiation-induced inhibition of thymidine incorporation in vivo as a measure of the initial slope and RBEn/. gamma

    SciTech Connect

    Dubravsky, N.B.; Maor, M.H.; Withers, H.R.

    1985-08-01

    Radiation damage can be measured by decreased incorporation of 3H-TdR. The early effect of total body irradiation of mice, with doses up to 300-400 rad, of gamma rays or neutrons, on thymidine-3H incorporation into the DNA of murine proliferating normal and tumor cells are described. Total body irradiation with single doses up to 300 rad resulted in a steep dose-dependent depression of 3H-TdR incorporation into the DNA of the jejunal crypt, testis, spleen, fibrosarcoma (FSa), and FSa metastasis cells. The dose required to depress 3H-TdR incorporation values to 37% of control level (D37/thymidine) after ..gamma..-irradiation was calculated to be 405, 443, 72, 303, and 531 rad, for jejunal crypt, testis, spleen, FSa metastasis, and FSa tumor cells, respectively. The depression progressed during the first 3 hours after irradiation. After neutron irradiation, the D37/thymidine was calculated to be 81, 140, 35, and 155 rad for jejunal crypt, testis, spleen, and FSa metastasis cells, respectively. The RBEn/..gamma.. derived from these results were 5.00, 3.16, 2.06, and 1.95 for jejunal crypt, testis, spleen, and FSa metastasis cells, respectively. These findings show that cell survival after small doses of irradiation correlate with the effect of irradiation on the actively proliferating cells at the time of irradiation.

  17. Assessment effect of gamma radiation on the flight ability of the peach fruit fly, Bactrocera zonata (Saunders).

    PubMed

    El-Gendy, Ismail Ragab; El-Aw, M A M; Hashem, A G; Draz, K A

    2013-12-01

    The sterile insect technique is one of the most methods of fruit flies control. Flight ability of the Peach Fruit Fly (PFF), Bactrocera zonata was conducted under laboratory conditions to evaluate the effect of gamma radiation on flight ability of PFF, B. zonata. Pupae of PFF, B. zonata, were irradiated in an air atmosphere at 24, 48 and 72 h before adult emergence with three doses of Cobalt 60 (10, 30 and 50 Gray) and tested against 6, 12 and 20 cm tube heights. Flight Ability Percentage (FAP) of PFF was carried out for newly emerged flies and six-days-old of adult flies. FAP of newly emerged-and six- days-old of adult flies was inversely proportional to the tube heights, doses of gamma rays and with progress the age of flies. The FAP value was significantly higher at 6 cm tube height, followed by 12 cm then 20 cm tube heights for all tested levels of gamma rays, respectively. PMID:24506040

  18. Gamma radiations induced improvement in dyeing properties and colorfastness of cotton fabrics dyed with chicken gizzard leaves extracts

    NASA Astrophysics Data System (ADS)

    Batool, Fatima; Adeel, Shahid; Azeem, Muhammad; Ahmad Khan, Ali; Ahmad Bhatti, Ijaz; Ghaffar, Abdul; Iqbal, Naeem

    2013-08-01

    Cotton fabric and chicken gizzard leaves powder were treated with different absorbed doses of 5, 10, 15, 20 and 25 kGy using Cs-137 gamma irradiator. Effects of different mordants on dyeing of un-irradiated and irradiated cotton fabrics were investigated in the CIE Lab system using Spectraflash SF650. Methods suggested by International Standard Organization (ISO) were followed throughout the study period. The results indicated that color strength of cotton fabric was significantly improved by the gamma ray treatment. Absorbed dose of 10 kGy was proved to be most effective in improving cotton dyeing properties compared with other levels of gamma radiation used in the study. The optimum temperature for dyeing was 60 °C with the time duration of 60 min using 4 g/L of electrolyte with alkali solubilized extract of chicken gizzard. Furthermore, 4% of iron (Fe) as pre-mordant and 1% of tannic acid (TA) as post-mordant proved to be more effective in enhancing the color fastness properties of irradiated cotton fabric.

  19. Radiation inactivation of Paenibacillus larvae and sterilization of American Foul Brood (AFB) infected hives using Co60 gamma rays

    Microsoft Academic Search

    Zenaida M. De Guzman; Cleofas R. Cervancia; Kris Genelyn B. Dimasuay; Mitos M. Tolentino; Gina B. Abrera; Ma. Lucia C. Cobar; Alejandro C. Fajardo; Noel G. Sabino; Chitho P. Feliciano

    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 1.6kGy) of gamma radiation emitted by a 60Co source. Surviving spores were counted and used to estimate the decimal reduction (D10) value. A dose of 0.2kGy was sufficient to inactivate 90%

  20. Characterization of an Escherichia coli mutant (radB101) sensitive to. gamma. and uv radiation, and methyl methanesulfonate

    SciTech Connect

    Sargentini, N.J.; Smith, K.C.

    1983-03-01

    After N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis of Escherichia coli K-12 (xthA14), an X-ray-sensitive mutant was isolated. This sensitivity is due to a mutation, radB101, which is located at 56.5 min on the E.coli K-12 linkage map. The radB101 mutation sensitized wild-type cells to ..gamma.. and uv radiation, and to methyl methanesulfonate. When known DNA repair-deficient mutants were ranked for their ..gamma..-radiation sensitivity relative to their uv-radiation sensitivity, their order was (starting with the most selectively ..gamma..-radiation-sensitive strain): recB21, radB101, wild type, polA1, recF143, lexA101, recA56, uvrD3, and uvrA6. The radB mutant was normal for ..gamma..- and uv-radiation mutagenesis, it showed only a slight enhancement of ..gamma..- and uv-radiation-induced DNA degradation, and it was approx. 60% deficient in recombination ability. The radB gene is suggested to play a role in the recA gene-dependent (Type III) repair of DNA single-strand breaks after ..gamma.. irradiation and in postreplication repair after uv irradiation for the following reasons: the radB strain was normal for the host-cell reactivation of ..gamma..- and uv-irradiated bacteriophage lambda; the radB mutation did not sensitize a recA strain, but did sensitize a polA strain to ..gamma.. and uv radiation; the radB mutation sensitized a uvrB strain to uv radiation.

  1. Effect of 1. 33 Mev gamma radiation and 0. 5 Mev electrons on the mechanical properties of graphite fiber composites

    Microsoft Academic Search

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

    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

  2. Characterization of ionizing radiation damage in DNA. Final report, February 1, 1977September 30, 1977. [Gamma radiation, fast neutrons, uv radiation

    Microsoft Academic Search

    1977-01-01

    An experimental method for the measurement of covalent DNA-protein cross-links in bacteriophage T7 based on phenol-water countercurrent distribution has been developed and a statistical model for quantitative interpretation of these measurements has been devised. It has been found that DNA-protein cross links accumulate linearly with dose in response to exposure to ⁶°Co gamma radiation at a rate .05 to .20

  3. Melatonin protection from chronic, low-level ionizing radiation.

    PubMed

    Reiter, Russel J; Korkmaz, Ahmet; Ma, Shuran; Rosales-Corral, Sergio; Tan, Dun-Xian

    2011-12-15

    In the current survey, we summarize the published literature which supports the use of melatonin, an endogenously produced molecule, as a protective agent against chronic, low-level ionizing radiation. Under in vitro conditions, melatonin uniformly was found to protect cellular DNA and plasmid super coiled DNA from ionizing radiation damage due to Cs(137) or X-radiation exposure. Likewise, in an in vivo/in vitro study in which humans were given melatonin orally and then their blood lymphocytes were collected and exposed to Cs(137) ionizing radiation, nuclear DNA from the cells of those individuals who consumed melatonin (and had elevated blood levels) was less damaged than that from control individuals. In in vivo studies as well, melatonin given to animals prevented DNA and lipid damage (including limiting membrane rigidity) and reduced the percentage of animals that died when they had been exposed to Cs(137) or Co(60) radiation. Melatonin's ability to protect macromolecules from the damage inflicted by ionizing radiation likely stems from its high efficacy as a direct free radical scavenger and possibly also due to its ability to stimulate antioxidative enzymes. Melatonin is readily absorbed when taken orally or via any other route. Melatonin's ease of self administration and its virtual absence of toxicity or side effects, even when consumed over very long periods of time, are essential when large populations are exposed to lingering radioactive contamination such as occurs as a result of an inadvertent nuclear accident, an intentional nuclear explosion or the detonation of a radiological dispersion device, i.e., a "dirty" bomb. PMID:22185900

  4. Indoleamine 2,3-dioxygenase mediates immune-independent human tumor cell resistance to olaparib, gamma radiation, and cisplatin.

    PubMed

    Maleki Vareki, Saman; Rytelewski, Mateusz; Figueredo, Rene; Chen, Di; Ferguson, Peter J; Vincent, Mark; Min, Weiping; Zheng, Xiufen; Koropatnick, James

    2014-05-15

    Indoleamine 2,3-dioxygenase-1 (IDO) is an immunosuppressive molecule expressed by most human tumors. IDO levels correlate with poor prognosis in cancer patients and IDO inhibitors are under investigation to enhance endogenous anticancer immunosurveillance. Little is known of immune-independent functions of IDO relevant to cancer therapy. We show, for the first time, that IDO mediates human tumor cell resistance to a PARP inhibitor (olaparib), gamma radiation, cisplatin, and combined treatment with olaparib and radiation, in the absence of immune cells. Antisense-mediated reduction of IDO, alone and (in a synthetic lethal approach) in combination with antisense to the DNA repair protein BRCA2 sensitizes human lung cancer cells to olaparib and cisplatin. Antisense reduction of IDO decreased NAD+ in human tumor cells. NAD+ is essential for PARP activity and these data suggest that IDO mediates treatment resistance independent of immunity and at least partially due to a previously unrecognized role for IDO in DNA repair. Furthermore, IDO levels correlated with accumulation of tumor cells in G1 and depletion of cells in G2/M of the cell cycle, suggesting that IDO effects on cell cycle may also modulate sensitivity to radiation and chemotherapeutic agents. IDO is a potentially valuable therapeutic target in cancer treatment, independent of immune function and in combination with other therapies. PMID:24784564

  5. Indoleamine 2,3-dioxygenase mediates immune-independent human tumor cell resistance to olaparib, gamma radiation, and cisplatin

    PubMed Central

    Vareki, Saman Maleki; Rytelewski, Mateusz; Figueredo, Rene; Chen, Di; Ferguson, Peter J.; Vincent, Mark; Min, Weiping; Zheng, Xiufen; Koropatnick, James

    2014-01-01

    Indoleamine 2,3-dioxygenase-1 (IDO) is an immunosuppressive molecule expressed by most human tumors. IDO levels correlate with poor prognosis in cancer patients and IDO inhibitors are under investigation to enhance endogenous anticancer immunosurveillance. Little is known of immune-independent functions of IDO relevant to cancer therapy. We show, for the first time, that IDO mediates human tumor cell resistance to a PARP inhibitor (olaparib), gamma radiation, cisplatin, and combined treatment with olaparib and radiation, in the absence of immune cells. Antisense-mediated reduction of IDO, alone and (in a synthetic lethal approach) in combination with antisense to the DNA repair protein BRCA2 sensitizes human lung cancer cells to olaparib and cisplatin. Antisense reduction of IDO decreased NAD+ in human tumor cells. NAD+ is essential for PARP activity and these data suggest that IDO mediates treatment resistance independent of immunity and at least partially due to a previously unrecognized role for IDO in DNA repair. Furthermore, IDO levels correlated with accumulation of tumor cells in G1 and depletion of cells in G2/M of the cell cycle, suggesting that IDO effects on cell cycle may also modulate sensitivity to radiation and chemotherapeutic agents. IDO is a potentially valuable therapeutic target in cancer treatment, independent of immune function and in combination with other therapies. PMID:24784564

  6. Time correlation of cosmic-ray-induced neutrons and gamma rays at sea level

    E-print Network

    Harilal, S. S.

    Time correlation of cosmic-ray-induced neutrons and gamma rays at sea level G. Miloshevsky n , A and evaporation processes of air nuclei are time-correlated. The occurrence of their counts in a fixed time interval is not a random (Poisson) distribution, but rather time-correlated bursts of counts

  7. Level density and gamma strength function in 162-Dy from inelastic 3-He scattering

    E-print Network

    A. Schiller; M. Guttormsen; E. Melby; J. Rekstad; S. Siem

    1999-12-02

    Complementary measurements have been performed for the level density and gamma strength function in 162-Dy using inelastic 3-He scattering. Comparing these results to previous measurements using the 163-Dy(3-He,alpha) reaction, reveals that the measured quantities above 1.5 MeV do not depend significantly on the nuclear reaction chosen.

  8. The ionization processes in the Fe XXVII region of hot iron plasma in the field of hard gamma radiation

    NASA Astrophysics Data System (ADS)

    Illarionov, A. F.

    1989-06-01

    A highly ionized hot plasma of an Fe-56-type heavy element in the field of hard ionizing gamma radiation is studied. Processes of ionization and recombination are discussed for a plasma consisting of fully ionized Fe XXVII and hydrogen-like Fe XXVI ions in the case of a large optical depth of the plasma with respect to photoionization by gamma-ray quanta. An equation of ionization balance is presented for a plasma in the Fe XXVII region formed around a powerful source of hard gamma-ray radiation.

  9. On the level of background radiation aboard a passenger airplane

    NASA Astrophysics Data System (ADS)

    Sidorin, A. I.

    2014-12-01

    Data on radioactivity measured aboard an airplane during two flights—Moscow-Tivat and Tivat-Moscow—are given. Radioactivity was measured every minute during these flights (from takeoff to landing) simultaneously with two radiometers (RD1706). These flights were at a height of about 10.7 km. From the end of ascension to the start of descension, the radiation was approximately at the same level (about 3 ?Sv/h), which is approximately 30 times higher than that for the land surface. A comparison of data obtained with these two instruments during these flights yielded their sufficiently good agreement. On the basis of measurement results, the probability of negative radiation effects on air passengers is assessed using available methodical recommendations. For a single flight, at average solar-activity levels, this probability proved to be negligibly small (about 3 × 10-7).

  10. 1989 neutron and gamma personnel dosimetry intercomparison study using RADCAL (Radiation Calibration Laboratory) sources

    SciTech Connect

    Sims, C.S.; Casson, W.H.; Patterson, G.R. (Oak Ridge National Lab., TN (USA)); Murakami, H. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Dept. of Health Physics); Liu, J.C. (Stanford Linear Accelerator Center, Menlo Park, CA (USA))

    1990-10-01

    The fourteenth Personnel Dosimetry Intercomparison Study (i.e., PDIS 14) was conducted during May 1-5, 1989. A total of 48 organizations (33 from the US and 15 from abroad) participated in PDIS 14. Participants submitted by mail a total of 1,302 neutron and gamma dosimeters for this mixed field study. The type of neutron dosimeter and the percentage of participants submitting that type are as follows: TLD-albedo (40%), direct interaction TLD (22%), track (20%), film (7%), combination (7%), and bubble detectors (4%). The type of gamma dosimeter and the percentage of participants submitting that type are as follows: TLD (84%) and film (16%). Radiation sources used in the six PDIS 14 exposures included {sup 252}Cf moderated by 15-cm D{sub 2}O, {sup 252}Cf moderated by 15-cm polyethylene (gamma-enhanced with {sup 137}Cs), and {sup 238}PuBe. Neutron dose equivalents ranged from 0.44--2.63 mSv and gamma doses ranged from 0. 01-1.85 mSv. One {sup 252}Cf(D{sub 2}O) exposure was performed at a 60{degree} angle of incidence (most performance tests are at perpendicular incidence). The average neutron dosimeter response for this exposure was 70% of that at normal incidence. The average gamma dosimeter response was 96% of that at normal incidence. A total of 70% of individual reported neutron dosimeter measurements were within {plus minus}50% of reference values. If the 0.01 mSv data are omitted, approximately 90% of the individual reported gamma measurements were within {plus minus}50% of reference values. 33 refs., 9 figs., 27 tabs.

  11. Radiation method for the measurement of mode-conversion levels

    Microsoft Academic Search

    P. J. B. Clarricoats; A. D. Olver; C. Parini

    1974-01-01

    A novel method for the determination of mode-conversion levels in overmoded waveguides is described. It relies on a swept-frequency measurement of the perturbation of the dominant-mode radiation pattern of the open-ended waveguide, owing to the presence of higher-order modes. Results are reported for mode-conversion effects in corrugated waveguides at frequencies near 9 GHz. Excellent agreement with the trapped-resonance method is

  12. Wafer-level radiation testing for hardness assurance

    Microsoft Academic Search

    M. R. Shaneyfelt; K. L. Hughes; J. R. Schwank; F. W. Sexton; D. M. Fleetwood; P. S. Winokur; E. W. Enlow

    1991-01-01

    To implement the qualified manufacturers list (QML) approach to hardness assurance in a practical and cost-effective manner, one must identify technology parameters that affect radiation hardness and bring them under statistical process control. To aid this effort, the authors have developed a wafer-level test system to map test-structure and IC response across a wafer. This system permits current-voltage and charge-pumping

  13. [gamma]-radiation-induced changes in the chemical and physical structure of poly(ethylene terephthalate)

    SciTech Connect

    Jin, Ho-Seon.

    1992-01-01

    Poly(ethylene terephthalate) (PET) film was irradiated with [gamma]-rays in air at doses from 0 to 620 Mrad, and at the rate of 0l8 to 1.0 Mrad/hr. Radiation-induced physical structure changes were studied by DMA and DSC measurements. Tensile properties were measured to find interrelationships with chemical and physical structure changes. Below 100 Mrad, PET shows little change in NMR and IR spectra. Fluorescence emission spectra, however, show the presence and increase of monohydroxy-substituted phenylene groups. This hydroxylation appears to stabilize the polymer. The phenylene group in PET also contributes to radiation-resistance. The amorphous-crystalline interfaces impede the penetration of oxygen and slow the oxidative chain scission. Between 100 and 215 Mrad, UV studies reveal that the rates of reaction begin to change rapidly. Chain scission appears to take place first in the interspherulitic amorphous regions and then in the intraspherulitic (interlamella) regions. [gamma]-Radiation-induced oxidative degradation shows aspects of both photolysis and of thermooxidative degradation (proton and carbon-13 NMR, and IR studies). It was concluded that the crystalline phase breaks down in to smaller crystallites, and these smaller crystallites grow in size by acting as nucleating sites. Tensile measurements show that throughout the range of irradiation studied the tensile strength at break and the percent elongation decrease. The tensile strength decreases uniformly and the percent elongation exhibits a more rapid decrease above 100 Mrad. The results of this study lead to the conclusion that [gamma]-radiation-induced oxidative degradation of PET involves products that are seen in both photolysis and thermooxidation.

  14. Effect of gamma radiation on native endolithic microorganisms from a radioactive waste deposit site.

    PubMed

    Pitonzo, B J; Amy, P S; Rudin, M

    1999-07-01

    A time-course experiment was conducted to evaluate the effects of gamma radiation on the indigenous microbiota present in rock obtained from Yucca Mountain, Nevada Test Site. Microcosms were constructed by placing pulverized Yucca Mountain rock in polystyrene cylinders. Continuous exposure (96 h) at a dose rate of 1.63 Gy/min was used to mimic the near-field environment surrounding waste canisters. The expected maximum surface dose rate from one unbreached canister designed to contain spent nuclear fuels is 0.06 Gy/min. Considering the current repository packing design, multiple canisters within one vault, the cumulative dose rate may well approach that used in this experiment. The microbial communities were characterized after receiving cumulative doses of 0, 0.098, 0. 58, 2.33, 4.67, 7.01 and 9.34 kGy. Radiation-resistant microorganisms in the pulverized rock became viable but nonculturable (VBNC) after a cumulative dose of 2.33 kGy. VBNC microorganisms lose the ability to grow on media on which they have routinely been cultured in response to the environmental stress imposed (i.e. radiation) but can be detected throughout the time course using direct fluorescence microscopy techniques. Two representative exopolysaccharide-producing isolates from Yucca Mountain were exposed to the same radiation regimen in sand microcosms. One isolate was much more radiation-resistant than the other, but both had greater resistance than the general microbial community based on culturable counts. However, when respiring cell counts (VBNC) were compared after irradiation, the results would indicate much more radiation resistance of the individual isolates and the microbial community in general. These results have significant implications for underground storage of nuclear waste as they indicate that indigenous microorganisms are capable of surviving gamma irradiation in a VBNC state. PMID:10381842

  15. Effect of gamma radiation on growth and survival of common seed-borne fungi in India

    NASA Astrophysics Data System (ADS)

    Maity, J. P.; Chakraborty, A.; Chanda, S.; Santra, S. C.

    2008-07-01

    The present work describes radiation-induced effects of major seeds like Oryza sativa Cv-2233, Oryza sativa Cv-Shankar, Cicer arietinum Cv-local and seed-borne fungi like Alternaria sp., Aspergillus sp., Trichoderma sp. and Curvularia sp. 60Co gamma source at 25 °C emitting gamma ray at 1173 and 1332 keV energy was used for irradiation. Dose of gamma irradiation up to 3 kGy (0.12 kGy/h) was applied for exposing the seed and fungal spores. Significant depletion of the fungal population was noted with irradiation at 1-2 kGy, whereas germinating potential of the treated grain did not alter significantly. However, significant differential radiation response in delayed seed germination, colony formation of the fungal spores and their depletion of growth were noticed in a dose-dependent manner. The depletion of the fungal viability (germination) was noted within the irradiation dose range of 1-2 kGy for Alternaria sp. and Aspergillus sp., while 0.5-1 kGy for Trichoderma sp. and Curvularia sp. However, complete inhibition of all the selected fungi was observed above 2.5 kGy.

  16. Statistical analysis of low-level material screening measurements via gamma-spectroscopy.

    PubMed

    Heisel, M; Kaether, F; Simgen, H

    2009-05-01

    Background estimations in neutrinoless double beta decay experiments (0nubetabeta) require reliable statistical limits on gamma-spectrometric low-level material screening measurements. For this purpose a custom method based on Bayesian statistics with reference to the international standard ISO 11929-7 is presented. The analysis combines the data from sample- and background spectra and comprises the physical knowledge of non-negative counting rates. It allows to incorporate multiple gamma lines of radionuclides. The confidence intervals pass continuously from two-sided intervals into single-sided upper limits. PMID:19251428

  17. Determination of endogenous gamma-hydroxybutyric acid (GHB) levels in antemortem urine and blood

    Microsoft Academic Search

    Albert A. Elian

    2002-01-01

    Gamma-hydroxybutyric acid’s (GHB’s) natural presence in the body has made the interpretation of its levels a challenging task for the forensic toxicologist. This study was designed to measure endogenous GHB levels in antemortem urine and blood samples. The range detected in urine was from 34 to 575?g\\/dl and in blood from 17 to 151?g\\/dl. The results indicate that the concentration

  18. A large volume low-level detector for measuring the gamma-radioactivity in water

    SciTech Connect

    Bressani, T.; Feliciello, A.; Tencone, B.; Tricomi, V.I.; Iazzi, F.; Minetti, B.; Serci, S.

    1988-02-01

    The main features of a low-level large volume detector for measuring in real time the ..gamma..-radioactivity in water are described. The detector is made of plastic scintillators interleaved with Pb converters. A particular geometry allowing an efficient rejection of the background due to cosmic rays is adopted. The detector is able to operate plunged underwater up to 30 m and has a sensitivity level of 10/sup -3/ Bq/ml.

  19. Consequences of Lethal-Whole-Body Gamma Radiation and Possible Ameliorative Role of Melatonin

    PubMed Central

    Mihandoost, Ehsan; Shirazi, Alireza; Mahdavi, Seied Rabie; Aliasgharzadeh, Akbar

    2014-01-01

    Gamma radiation induces the generation of free radicals, leading to serious cellular damages in biological systems. Radioprotectors act as prophylactic agents that are administered to shield normal cells and tissues from the deleterious effects of radiation. Melatonin synergistically acts as an immune-stimulator and antioxidant. We investigated the possible radioprotective role of melatonin (100?mg/kg i.p.) against lethal-whole-body radiation- (10?Gy) induced sickness, body weight loss, and mortality in rats. Results of the present study suggest that exposure to lethal-whole-body radiation incurred mortality, body weight loss, and apoptosis and it also depleted the immunity and the antioxidant status of the rats. Our results show that melatonin pretreatment provides protection against radiation induced mortality, oxidative stress, and immune-suppression. The melatonin pretreated irradiated rats showed less change in body weight as compared to radiation only group. On the other hand, melatonin appeared to have another radioprotective role, suggesting that melatonin may reduce apoptosis through a caspase-3-mediated pathway by blocking caspase-3 activity. PMID:25431791

  20. Consequences of lethal-whole-body gamma radiation and possible ameliorative role of melatonin.

    PubMed

    Mihandoost, Ehsan; Shirazi, Alireza; Mahdavi, Seied Rabie; Aliasgharzadeh, Akbar

    2014-01-01

    Gamma radiation induces the generation of free radicals, leading to serious cellular damages in biological systems. Radioprotectors act as prophylactic agents that are administered to shield normal cells and tissues from the deleterious effects of radiation. Melatonin synergistically acts as an immune-stimulator and antioxidant. We investigated the possible radioprotective role of melatonin (100 mg/kg i.p.) against lethal-whole-body radiation- (10 Gy) induced sickness, body weight loss, and mortality in rats. Results of the present study suggest that exposure to lethal-whole-body radiation incurred mortality, body weight loss, and apoptosis and it also depleted the immunity and the antioxidant status of the rats. Our results show that melatonin pretreatment provides protection against radiation induced mortality, oxidative stress, and immune-suppression. The melatonin pretreated irradiated rats showed less change in body weight as compared to radiation only group. On the other hand, melatonin appeared to have another radioprotective role, suggesting that melatonin may reduce apoptosis through a caspase-3-mediated pathway by blocking caspase-3 activity. PMID:25431791

  1. Effects of High Dietary Iron and Gamma Radiation on Oxidative Stress and Bone

    E-print Network

    Yuen, Evelyn P

    2013-04-19

    linked oxidative stress to bone loss with aging and estrogen deficiency. Whether the increased iron stores and radiation that astronauts face are exacerbating their extreme bone loss while in space is unclear. We hypothesized that elevated iron levels...

  2. THE COMPARATIVE INVESTIGATION OF METHODS OF THE DETERMINATION OF SULFUR IN ORGANIC PRODUCTS USING ABSORPTION OF X AND GAMMA RADIATIONS

    Microsoft Academic Search

    L. Gorski; J. Grabczak

    1963-01-01

    The possibilities of applicntion of isotopic sources of gamma and x ; radiations for the determination of sulfur in hydrocarbons are discussed. The ; analytical methods are based on the absorption of radiation utilizing a ; difference between the absorption coefficients of hydrocarbon and sulfur for the ; energy about 20 kev. The properties of a Sn¹¹³ source whlch has

  3. Effect of Gamma Radiation on the Physiological Properties and Genetic Materials of Streptomyces albaduncus and S. erythogresius

    Microsoft Academic Search

    L. A. A. MOUSSA; F. A. MANSOUR; M. S. SERAG; S. A. M. ABOU

    Out of 14 isolates of actinomycetes, isolated from Egyptian soils, the two thermophilic isolates identified as Streptomyces albaduncus and S. erythogresius showed the highest antimicrobial activities against bacteria, moulds and yeasts among them. Both isolates were exposed to increasing doses of gamma radiation up to 5 kGy. All radiation doses used did not affect the physiological properties, but relativity higher

  4. Relationship between the repair of radiation-induced DNA damage and recovery from potentially lethal damage in 9L rat brain tumor cells. [Gamma radiation

    Microsoft Academic Search

    S. C. vanAnkeren; K. T. Wheeler

    1984-01-01

    The kinetics of repair of radiation-induced DNA damage and recovery from radiation-induced potentially lethal damage (PLD) for fed plateau-phase 9L\\/Ro rat brain tumor cells were compared after single doses of gamma-radiation and after combined treatment with 3 micrograms of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU)\\/ml given 16 hr prior to irradiation. DNA damage and repair were assayed using alkaline filter elution, while cell survival

  5. Effect of low-dose (1 kGy) gamma radiation and selected phosphates on the microflora of vacuum-packaged ground pork

    SciTech Connect

    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 kGy (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.

  6. Determination of the Dark Matter profile from the EGRET excess of diffuse Galactic gamma radiation

    E-print Network

    Markus Weber

    2007-10-26

    The excess above 1 GeV in the energy spectrum of the diffuse Galactic gamma radiation, measured with the EGRET experiment, can be interpreted as the annihilation of Dark Matter (DM) particles. The DM is distributed in a halo around the Milky Way. Considering the directionality of the gamma ray flux it is possible to determine the halo profile. The DM within the halo has a smooth and a clumpy component.These components can have different profiles as suggested by N-body simulations and the data is indeed compatible with a NFW profile for the diffuse component and a cored profile for the clumpy component.These DM clumps can be partly destroyed by tidal forces from interactions with stars and the gravitational potential of the Galactic disc.This effect mainly decreases the annihilation signal from the Galactic centre (GC). In this paper constraints on the different profiles and the survival probability of the clumps are discussed.

  7. Absorption of Very High Energy Gamma-Rays by Intergalactic Infrared Radiation: A New Determination

    E-print Network

    F. W. Stecker; O. C. De Jager

    1998-04-20

    We present a new calculation of the intergalactic gamma-ray absorption coefficient as a function of both energy and redshift. In reexamining this problem, we make use of a new, empirically based calculation (as opposed to previous model calculations) of the intergalactic infrared radiation field. We find smaller opacities than those given previously (Stecker & De Jager 1997). We apply our results to the new observations of the flaring gamma-ray spectra of Mrk421 and Mrk501, both at a redshift of apx. 0.03. Our new calculations indicate that there should be no significant curvature in the spectra of these sources for energies below 10 TeV, as indicated by recent observations. However, the intrinsic spectra of these sources should be harder by apx. 0.2 to 0.45 in the spectral index in the 1 to 10 TeV range with an intergalactic absorption cutoff above apx. 20 TeV.

  8. Antibacterial properties of Au doped polycarbonate synthesized by gamma radiation assisted diffusion method

    NASA Astrophysics Data System (ADS)

    Hareesh, K.; Deore, Avinash V.; Dahiwale, S. S.; Sanjeev, Ganesh; Kanjilal, D.; Ojha, Sunil; Dhole, N. A.; Kodam, K. M.; Bhoraskar, V. N.; Dhole, S. D.

    2015-07-01

    Gold (Au)-Polycarbonate (PC) matrix was prepared by gamma radiation assisted diffusion of Au nanoparticles in PC matrix. UV-Visible spectroscopy showed the surface plasmon resonance around 550 nm which corresponds to Au and this peak shift towards lower wavelength i.e. blue shift indicating the decrease in particle size of Au. Rutherford Backscattering (RBS) experiment confirmed the diffusion of Au in PC and depth of diffusion is found to be around 0.85 ?m. X-ray Diffractogram (XRD) results also revealed the diffusion of Au in PC where the peak observed at 2??38.29° which correspond to the FCC structure. Scanning Electron Microscope (SEM) images showed the hexagonal shaped Au nanoparticles and average particle size is found to be around 110 nm. These samples also showed anti-bacterial properties with both gram positive and gram negative bacteria's and revealed the inhibition of the overall growth of the bacteria with gamma dose.

  9. Radiative-neutron-capture gamma-ray analysis by a linear combination technique

    USGS Publications Warehouse

    Tanner, A.B.; Bhargava, R.C.; Senftle, F.E.; Brinkerhoff, J.M.

    1972-01-01

    The linear combination technique, when applied to a gamma-ray spectrum, gives a single number indicative of the extent to which the spectral lines of a sought element are present in a complex spectrum. Spectra are taken of the sought element and of various other substances whose spectra interfere with that of the sought element. A weighting function is then computed for application to spectra of unknown materials. The technique was used to determine calcium by radiative-neutron-capture gamma-ray analysis in the presence of interfering elements, notably titanium, and the results were compared with those for two popular methods of peak area integration. Although linearity of response was similar for the methods, the linear combination technique was much better at rejecting interferences. For analyses involving mixtures of unknown composition the technique consequently offers improved sensitivity. ?? 1972.

  10. Gamma-ray escape peak characteristics of radiation-damaged reverse-electrode germanium coaxial detectors

    NASA Astrophysics Data System (ADS)

    Pehl, Richard H.; Hull, Ethan L.; Madden, Norman W.; Xing, Jingshu; Friesel, Dennis L.

    1996-02-01

    A comparison of the characteristics of full-energy gamma-ray peaks and their corresponding escape peaks when high energy photons interact in radiation damaged reverse-electrode (n-type) germanium coaxial detectors is presented. Coaxial detector geometry is the dominant factor, causing charge collection to be dramatically better for interactions occurring near the outer periphery of the detector as well as increasing of the probability of escape events occurring in this region. It follows that the resolution of escape peaks is better than that of ordinary gamma-ray peaks. This is experimentally verified. A nearly identical but undamaged detector exhibited significant Doppler broadening of single escape peaks. Because double escape events preferentially occur at outer radii, energy shifts of double escape reflect extremely small amounts of charge trapping in undamaged detectors.

  11. Gamma-Ray Escape Peak Characteristics of Radiation Damaged Reverse-Electrode Germanium Detectors

    NASA Astrophysics Data System (ADS)

    Hull, E. L.; Xing, J. S.; Friesel, D. L.; Pehl, R. H.; Madden, N. M.

    1996-05-01

    A comparison between the characteristics of escape peaks and ordinary, multiple Compton and photoelectrically interacting, full-energy gamma-ray peaks from radiation damaged reverse-electrode (n-type) germanium coaxial detectors is presented. Coaxial detector geometry is the dominant factor, causing charge collection to be dramatically better near the outer periphery of the detector as well as increasing the probability of escape events occurring in this region. It follows that the resolution of escape peaks is better than that of ordinary gamma-ray peaks. This is experimentally verified. However, a nearly identical but undamaged detector exhibited significant Doppler broadening of single escape peaks. Because double escape events preferentially occur at outer radii, energy shifts in double escape peaks reflect extremely small amounts of charge trapping.

  12. Signature of gravitational radiation in afterglow of short Gamma-Ray Bursts?

    E-print Network

    Fan, Yi-Zhong; Wei, Da-Ming

    2013-01-01

    Short Gamma-Ray Bursts (GRBs) are brief intense emission of $\\gamma-$rays characterized by a duration shorter than 2 seconds and some, if not all of them, are likely powered by the coalescence of binary neutron stars. Sometimes the remnants may be supramassive highly-magnetized neutron stars (magnetars) with a typical rotational period $P_0 \\sim 1$ ms and the rapid rotation prevents the gravitational collapse until a good fraction of the rotational energy has been lost. Plausible observational evidence for the short-living magnetar central engine reported in the literature is the X-ray plateaus followed by an abrupt decline identified in some short GRB afterglow. We however find that with a moderate/high radiation efficiency favored by the very dim optical afterglow emission, the observed duration of some X-ray plateaus are significantly shorter than that expected in the dipole radiation model (i.e., the magnetar collapsed considerably earlier than the prediction of the pure dipole radiation). We suggest that...

  13. Effect of gamma radiation on chlorobutyl rubber vulcanized by three different crosslinking systems

    NASA Astrophysics Data System (ADS)

    Scagliusi, Sandra R.; Cardoso, Elisabeth L. C.; Lugao, Ademar B.

    2012-09-01

    The development of halogenated butyl rubber (chlorobutyl) in the 1950s and 1960s greatly extended the usefulness of butyl. Their properties allowed the development of more durable tubeless tires with the air retaining innerliner, chemically bonded to the body of the tire. Tire innerliners are by far the largest application for halobutyl. When polymers are subjected to high energy radiation, a number of chemical reactions may occur following the initial ionization and excitation events. These reactions lead to changes in the molecular weight of the polymer through scission (S) and crosslinking (X) of the molecules and affect the physical and mechanical properties. In the halobutyl rubbers the chain scission may predominate. This work aims to show effects of gamma radiation in properties of chlorobutyl rubbers vulcanized with sulfur, sulfur donor and phenolic resin. The butyl rubber has been already studied by us previously. The samples were characterized before and after irradiation. Gamma radiation doses used were: 25 kGy, 50 kGy, 100 kGy, 150 kGy and 200 kGy, in order to identify which cure system is the most stable under irradiation. In this study we observed that the properties of all samples were affected irrespective of the vulcanization system.

  14. OXIDATIVE STABILITY OF CRUDE MID-OLEIC SUNFLOWER OILS FROM SEEDS WITH HIGH GAMMA AND DELTA TOCOPHEROL LEVELS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To determine the effects of increasing the level of gamma tocopherol in sunflower oil, sunflowers were developed that contained various levels of gamma tocopherols with corresponding decreases in alpha tocopherol. Mid-oleic sunflower seeds containing various profiles of tocopherols ranging from tra...

  15. Gamma radiation induced effects in floppy and rigid Ge-containing chalcogenide thin films

    SciTech Connect

    Ailavajhala, Mahesh S.; Mitkova, Maria [Department of Electrical Engineering, Boise State University, 1910 University Dr. Boise, Idaho 83725-2075 (United States); Gonzalez-Velo, Yago; Barnaby, Hugh; Kozicki, Michael N.; Holbert, Keith [School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287-9309 (United States); Poweleit, Christian [Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States); Butt, Darryl P. [Department of Material Science and Engineering, Boise State University, 1910 University Dr. Boise, Idaho 83725-2090 (United States)

    2014-01-28

    We explore the radiation induced effects in thin films from the Ge-Se to Ge-Te systems accompanied with silver radiation induced diffusion within these films, emphasizing two distinctive compositional representatives from both systems containing a high concentration of chalcogen or high concentration of Ge. The studies are conducted on blanket chalcogenide films or on device structures containing also a silver source. Data about the electrical conductivity as a function of the radiation dose were collected and discussed based on material characterization analysis. Raman Spectroscopy, X-ray Diffraction Spectroscopy, and Energy Dispersive X-ray Spectroscopy provided us with data about the structure, structural changes occurring as a result of radiation, molecular formations after Ag diffusion into the chalcogenide films, Ag lateral diffusion as a function of radiation and the level of oxidation of the studied films. Analysis of the electrical testing suggests application possibilities of the studied devices for radiation sensing for various conditions.

  16. The use of gamma radiation for the elimination of Salmonella from frozen meat.

    PubMed

    Ley, F J; Kennedy, T S; Kawashima, K; Roberts, D; Hobbs, B C

    1970-06-01

    The use of a gamma radiation process for the elimination of Salmonella from frozen meat is considered with particular reference to the treatment of boned-out horsemeat and kangaroo meat imported into the UK and intended for use as pet meat.Examination of dose/survival curves produced for several serotypes of Salmonella in frozen meat shows that a radiation dose of 0.6 Mrad. will reduce a population by at least a factor of 10(5). The influence on the radiation resistance of salmonellas of such factors as preirradiation growth in the meat and temperature during irradiation have been examined and considered. It is also demonstrated with both preinoculated and naturally contaminated meat that postirradiation storage in the frozen state does not lead to the revival of irradiated salmonellas.The properties of Salmonella survivors deliberately produced in meat using conditions of irradiation designed to simulate a commercial process are studied after six recycling treatments through the process. There were no important changes in characteristics normally used for identification of Salmonella but radiation resistance was lowered. Survivors grown in situ in meat after irradiation showed an abnormally long lag phase, and removal of competitive microflora in meat by the radiation treatment can influence the growth of salmonellas. PMID:4914090

  17. Effect of surface ion charge transfer on electric conductivity of gas-polymer heterogeneous structure in pulsed. gamma. radiation

    SciTech Connect

    Elokhin, A.P.; Makeev, S.N.; Filatov, N.F.

    1988-11-01

    The radiation electric conductivity of gas-polymer heterogeneous structures with plane-parallel geometry of the electrodes in pulsed ..gamma.. radiation in the 5 x 10/sup 3/-10/sup 5/ Gy x sec/sup -1/ dose rate range was analyzed in consideration of surface ion charge transfer. An analytical expression was obtained for the radiation leakage current and it can be used in solving practical problems.

  18. Gamma spectroscopic measurements using the PID350 pixelated CdTe radiation detector

    E-print Network

    Karafasoulis, K; Seferlis, S; Papadakis, I; Loukas, D; Lambropoulos, C; Potiriadis, C

    2010-01-01

    Spectroscopic measurements are presented using the PID350 pixelated gamma radiation detectors. A high-speed data acquisition system has been developed in order to reduce the data loss during the data reading in case of a high flux of photons. A data analysis framework has been developed in order to improve the resolution of the acquired energy spectra, using specific calibration parameters for each PID350's pixel. Three PID350 detectors have been used to construct a stacked prototype system and spectroscopic measurements have been performed in order to test the ability of the prototype to localize radioactive sources.

  19. Gamma spectroscopic measurements using the PID350 pixelated CdTe radiation detector

    E-print Network

    K. Karafasoulis; K. Zachariadou; S. Seferlis; I. Papadakis; D. Loukas; C. Lambropoulos; C. Potiriadis

    2010-11-15

    Spectroscopic measurements are presented using the PID350 pixelated gamma radiation detectors. A high-speed data acquisition system has been developed in order to reduce the data loss during the data reading in case of a high flux of photons. A data analysis framework has been developed in order to improve the resolution of the acquired energy spectra, using specific calibration parameters for each PID350's pixel. Three PID350 detectors have been used to construct a stacked prototype system and spectroscopic measurements have been performed in order to test the ability of the prototype to localize radioactive sources.

  20. Energy response of agar-alanine phantom dosimeter to gamma radiation

    SciTech Connect

    Ciesielski, B.; Wielopolski, L.; Reinstein, L.E.

    1988-05-01

    Calculations of the energy response of an electron paramagnetic resonance (EPR) signal induced by gamma radiation in an agar-alanine phantom dosimeter are presented. Theoretically calculated slopes of the EPR signal calibration lines are comparable with those obtained experimentally for low-(50 kVp), medium-(662 keV), and high-(15 MVp) energy photons. The sensitivity of the phantom dosimeter (EPR signal amplitude/Gray) varies less than 2% within the 150- to 20-MeV energy range. For energies above 150 keV, the influence of variations in the size of alanine crystals is negligible.

  1. Determining the Impact of Concrete Roadways on Gamma Ray Background Readings for Radiation Portal Monitoring Systems

    E-print Network

    Ryan, Christopher Michael

    2012-07-16

    to the background of the detectors.18 II.B. Gamma ray interactions While there are more than 3,000 known nuclides, only about 270 of them are stable.19 The rest are radioactive and decay into other nuclides by emitting radiation. There are at least nine...% Iraq; 2% Canada; 3% United States; 20% Other FSU Countries; 7% Kazakhstan; 5% Ukraine; 5% Russia; 24% Remainder; 26% 4 Many USG assistance programs provide RPMs for use at POEs to intercept smuggled nuclear material. RPMs are designed...

  2. 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.

  3. Abdominal {gamma}-Radiation Induces an Accumulation of Function-Impaired Regulatory T Cells in the Small Intestine

    SciTech Connect

    Billiard, Fabienne; Buard, Valerie; Benderitter, Marc [Institut de Radioprotection et de Surete Nucleaire, Direction de la Radioprotection de l'Homme, B.P. no. 17, Fontenay-aux-Roses (France); Linard, Christine, E-mail: christine.linard@irsn.fr [Institut de Radioprotection et de Surete Nucleaire, Direction de la Radioprotection de l'Homme, B.P. no. 17, Fontenay-aux-Roses (France)

    2011-07-01

    Purpose: To assess the frequency and the functional characteristics of one major component of immune tolerance, the CD4{sup +}FoxP3{sup +} regulatory T cells (Tregs) in a mouse model of abdominal irradiation. Methods and Materials: Mice were exposed to a single abdominal dose of {gamma}-radiation (10 Gy). We evaluated small intestine Treg infiltration by Foxp3 immunostaining and the functional suppressive activity of Tregs isolated from mesenteric lymph nodes. Results: Foxp3 immunostaining showed that radiation induced a long-term infiltration of the intestine by Tregs (levels 5.5 times greater than in controls). Co-culture of Tregs from mesenteric lymph nodes with CD4{sup +} effector cells showed that the Tregs had lost their suppressive function. This loss was associated with a significant decrease in the levels of Foxp3, TGF-{beta}, and CTLA-4 mRNA, all required for optimal Treg function. At Day 90 after irradiation, Tregs regained their suppressive activity as forkhead box P3 (Foxp3), transforming growth factor beta (TGF-{beta}), and cytotoxic T-lymphocyte antigen 4 (CTLA-4) expression returned to normal. Analysis of the secretory function of mesenteric lymph node Tregs, activated in vitro with anti-CD3/anti-CD28 Abs, showed that this dysfunction was independent of a defect in interleukin-10 secretion. Conclusion: Radiation caused a long-term accumulation of function-impaired Foxp3{sup +}CD4{sup +} Tregs in the intestine. Our study provides new insights into how radiation affects the immune tolerance in peripheral tissues.

  4. A meta-analysis of leukaemia risk from protracted exposure to low-dose gamma radiation

    PubMed Central

    Schubauer-Berigan, M K

    2010-01-01

    Context More than 400?000 workers annually receive a measurable radiation dose and may be at increased risk of radiation-induced leukaemia. It is unclear whether leukaemia risk is elevated with protracted, low-dose exposure. Objective We conducted a meta-analysis examining the relationship between protracted low-dose ionising radiation exposure and leukaemia. Data sources Reviews by the National Academies and United Nations provided a summary of informative studies published before 2005. PubMed and Embase databases were searched for additional occupational and environmental studies published between 2005 and 2009. Study selection We selected 23 studies that: (1) examined the association between protracted exposures to ionising radiation and leukaemia excluding chronic lymphocytic subtype; (2) were a cohort or nested case–control design without major bias; (3) reported quantitative estimates of exposure; and (4) conducted exposure–response analyses using relative or excess RR per unit exposure. Methods Studies were further screened to reduce information overlap. Random effects models were developed to summarise between-study variance and obtain an aggregate estimate of the excess RR at 100?mGy. Publication bias was assessed by trim and fill and Rosenthal's file drawer methods. Results We found an ERR at 100?mGy of 0.19 (95% CI 0.07 to 0.32) by modelling results from 10 studies and adjusting for publication bias. Between-study variance was not evident (p=0.99). Conclusions Protracted exposure to low-dose gamma radiation is significantly associated with leukaemia. Our estimate agreed well with the leukaemia risk observed among exposed adults in the Life Span Study (LSS) of atomic bomb survivors, providing increased confidence in the current understanding of leukaemia risk from ionising radiation. However, unlike the estimates obtained from the LSS, our model provides a precise, quantitative summary of the direct estimates of excess risk from studies of protracted radiation exposures. PMID:20935290

  5. Effects of Gamma Radiation on Individual and Mixed Ion Exchange Resins

    SciTech Connect

    Baumann, E.W.

    2003-01-06

    The ion exchange resins that are used to deionize moderator in the reactor purification systems may accumulate sufficient radiation dose to damage the resins. This radiation damage would be manifested by: (1) loss of useful exchange capacity of the bed, which is costly since resins from the reactor deionizers are not reused; (2) shrinking or swelling of the resins, which may have some effect on the hydraulic behavior of the beds; (3) release of resin degradation products into the process stream, which pollutes moderator with impurities and precursors of the neutron-induced radioisotopes. This document details results of a laboratory study to determine the magnitude of these three effects by gamma irradiation of individual resins and their mixtures.

  6. TETRA observation of gamma-rays at ground level associated with nearby thunderstorms

    PubMed Central

    Ringuette, Rebecca; Case, Gary L; Cherry, Michael L; Granger, Douglas; Guzik, T Gregory; Stewart, Michael; Wefel, John P

    2013-01-01

    [1] Terrestrial gamma-ray flashes (TGFs)—very short, intense bursts of electrons, positrons, and energetic photons originating from terrestrial thunderstorms—have been detected with satellite instruments. TGF and Energetic Thunderstorm Rooftop Array (TETRA), an array of NaI(Tl) scintillators at Louisiana State University, has now been used to detect similar bursts of 50?keV to over 2?MeV gamma-rays at ground level. After 2.6?years of observation, 24 events with durations 0.02–4.2?ms have been detected associated with nearby lightning, three of them coincident events observed by detectors separated by ?1000?m. Nine of the events occurred within 6?ms and 5 km of negative polarity cloud-to-ground lightning strokes with measured currents in excess of 20?kA. The events reported here constitute the first catalog of TGFs observed at ground level in close proximity to the acceleration site.

  7. Characterization of x- and gamma- radiation in relativistically intense laser-solid interactions

    NASA Astrophysics Data System (ADS)

    Hou, Bixue; Zulick, Calvin; Zhao, Zhen; Nees, John; Batson, Thomas; Maksimchuk, Anatoly; Thomas, Alexander G. R.; Krushelnick, Karl; Center for Ultrafast Optical Science Team

    2013-10-01

    Using a high resolution (?/ ?? > 100) high purity germanium detector, the angular and material dependence, and the intensity scaling, of bremsstrahlung gamma radiation from relativistically intense (I > 1018 W/cm2) laser-solid interactions have been characterized at energies between 0.1 and 1 MeV with the high-repetition rate (500 Hz) Lambda-Cubed laser facility. The bremsstrahlung spectra of SiO2, Mo, and Eu2O3 were observed to have two-temperature energy distributions, corresponding to two different groups of electrons and depending on both laser intensity and observation angle. The spectra and source sizes of hard x-radiation under 0.1 MeV are also studied. These x-ray sources are being developed for phase-contrast imaging. Using a high resolution (?/ ?? > 100) high purity germanium detector, the angular and material dependence, and the intensity scaling, of bremsstrahlung gamma radiation from relativistically intense (I > 1018 W/cm2) laser-solid interactions have been characterized at energies between 0.1 and 1 MeV with the high-repetition rate (500 Hz) Lambda-Cubed laser facility. The bremsstrahlung spectra of SiO2, Mo, and Eu2O3 were observed to have two-temperature energy distributions, corresponding to two different groups of electrons and depending on both laser intensity and observation angle. The spectra and source sizes of hard x-radiation under 0.1 MeV are also studied. These x-ray sources are being developed for phase-contrast imaging. Support provided by DHS (EECS-0833499), AFOSR (FA99550-12-1-0310), ARO (W911NF-11-1-0116).

  8. Progenitors Mobilized by Gamma-Tocotrienol as an Effective Radiation Countermeasure

    PubMed Central

    Singh, Vijay K.; Wise, Stephen Y.; Fatanmi, Oluseyi O.; Scott, Jessica; Romaine, Patricia L. P.; Newman, Victoria L.; Verma, Amit; Elliott, Thomas B.; Seed, Thomas M.

    2014-01-01

    The purpose of this study was to elucidate the role of gamma-tocotrienol (GT3)-mobilized progenitors in mitigating damage to mice exposed to a supralethal dose of cobalt-60 gamma-radiation. CD2F1 mice were transfused 24 h post-irradiation with whole blood or isolated peripheral blood mononuclear cells (PBMC) from donors that had received GT3 72 h prior to blood collection and recipient mice were monitored for 30 days. To understand the role of GT3-induced granulocyte colony-stimulating factor (G-CSF) in mobilizing progenitors, donor mice were administered a neutralizing antibody specific to G-CSF or its isotype before blood collection. Bacterial translocation from gut to heart, spleen and liver of irradiated recipient mice was evaluated by bacterial culture on enriched and selective agar media. Endotoxin in serum samples also was measured. We also analyzed the colony-forming units in the spleens of irradiated mice. Our results demonstrate that whole blood or PBMC from GT3-administered mice mitigated radiation injury when administered 24 h post-irradiation. Furthermore, administration of a G-CSF antibody to GT3-injected mice abrogated the efficacy of blood or PBMC obtained from such donors. Additionally, GT3-mobilized PBMC inhibited the translocation of intestinal bacteria to the heart, spleen, and liver, and increased colony forming unit-spleen (CFU-S) numbers in irradiated mice. Our data suggests that GT3 induces G-CSF, which mobilizes progenitors and these progenitors mitigate radiation injury in recipient mice. This approach using mobilized progenitor cells from GT3-injected donors could be a potential treatment for humans exposed to high doses of radiation. PMID:25423021

  9. Risk evaluation - conventional and low level effects of radiation

    SciTech Connect

    Bond, V.P.; Varma, M.N.

    1984-04-01

    Any discussion of the risk of exposure to potentially-hazardous agents in the environment inevitably involves the question of whether the dose effect curve is of the threshold or linear, non-threshold type. A principal objective of this presentation is to show that the function is actually two separate relationships, each representing distinctly different functions with differing variables on the axes, and each characteristic of quite different functions with differing variables on the axes, and each characteristic of quite different disciplines (i.e., the threshold function, of Pharmacology, Toxicology and Medicine (PTM); the linear, non-threshold function, of Public Health including safety and accident statistics (PHS)). It is shown that low-level exposure (LLE) to radiation falls clearly in the PHS category. A function for cell dose vs. the fraction of single cell quantal responses is characterized, which reflects the absolute and relative sensitivities of cells. Acceptance of this function would obviate any requirement for the use in Radiation Protection of the concepts of a standard radiation, Q, dose equivalent and rem. 9 references, 4 figures.

  10. Ultrasound Thermometry for Therapy-level Radiation Dosimetry

    NASA Astrophysics Data System (ADS)

    Taylor, Courtney

    2010-03-01

    Radiation oncology is the process of administering a specified dose of radiation to a patient currently receiving treatment for a form of cancer. In this process, it is vital to know the delivered dose for a given radiation beam to correctly treat a patient. The primary reference standard for absorbed dose is established using water calorimetry. The absorbed dose, typically of order 1 Gy (J/kg) at therapy levels, is realized by measuring sub-millikelvin temperature changes using a thermistor in a sensitive Wheatstone bridge. Ultrasound technology has been investigated as an alternative to thermistor measurements since the speed of sound propagation in water varies with temperature. With ultrasonic time-of-flight and highly sensitive phase detection techniques, temperature sensitivity comparable to that of the thermistor bridge has been achieved without introducing non-water materials into the test area. A single ultrasound transducer transmitting and receiving at 5.0 MHz throughout the length of the water phantom, and the phase change of the sound wave was used to determine temperature increase from an irradiative source at specified depths of the phantom. In this experiment, the exposure period was varied from 15s to 160s cyclically by modulating a heat lamp, and a profile of the measured temperature response as a function of the period was obtained using Fourier analysis. Due to the large temperature gradient in the water phantom, measurements are prone to convection which was indeed observed and will be discussed.

  11. What Is The Optimal Level of Solar Radiation Management?

    NASA Astrophysics Data System (ADS)

    Irvine, Peter; Ridgwell, Andy; Lunt, Dan

    2010-05-01

    Solar radiation management (SRM), achieved by stratospheric aerosol injections or by placing a sunshade in orbit, has the potential to cool the Earth's climate to pre-industrial temperatures even with large quantities of CO2 in the atmosphere. Many authors have observed that in such a geoengineered world there would be an undesirable reduction in the intensity of the hydrological cycle. With a large geoengineering intervention in the climate there are many known issues, and potentially some unexpected issues, which could arise as a result. If climate geoengineering is to be conducted, what is the optimal level of solar radiation management? Here we present the results from a set of experiments using the UK Met Office HadCM3L coupled GCM to simulate the effect of reductions in insolation on the climate of a world with four times the pre-industrial CO2 level. We consider 10 levels of SRM geoengineering from 100% application, returning global average temperature to pre-industrial levels, to 10% of this reduction in insolation. A pre-industrial control, two and four times pre-industrial CO2 experiments were also conducted. All the simulations were run for 400 years to allow the climate to reach a new equilibrium, with the last 100 years used for the climatological averages. In addition the Glimmer Ice Sheet model was used to simulate the viability of the Greenland ice sheet in each of these climates, the results of this section of the work are already published. We assess the effects of different levels of geoengineering on a high CO2 world by a number of different methods, including: temperature and precipitation changes and the stability of the Greenland Ice-Sheet. We include a measure of the change in the climate due solely to the geoengineering intervention, accounting for imperfect mitigation. We combine these variables to find a first estimate of the optimal level of solar radiation management for a high CO2 world. Global average temperature and precipitation have been shown to drop with increasing levels of SRM geoengineering, however our results show that levels of crought may remain constant or even decrease relative to the unmitigated, high CO2 world. We show that the Greenland ice sheet remains stable, in its preindustrial state, with a reduction in insolation of 60% of that required to cool the Earth to pre-industrial temperatures. We also find that the mitigation of global warming at low levels of geoengineering has few imperfections but that at higher levels of geoengineering there are profound imperfections. We combine these results to determine a subjective optimal level of geoengineering. Our results show that to minimize the level of undesired geoengineering-induced climate changes and reductions in global precipitation, whilst preserving the Greenland ice sheet, 60% of the full reduction in insolation would be required. This partial geoengineering would be cheaper to implement and would be less likely to produce unexpected side-effects.

  12. Gamma radiation and dose rate investigations on the Adriatic islands of magmatic origin.

    PubMed

    Petrinec, Branko; Frani?, Zdenko; Leder, Nenad; Tsabaris, Christos; Bituh, Tomislav; Marovi?, Gordana

    2010-06-01

    Natural radioactivity of Middle-Adriatic Sea islands and islets was measured. Gamma spectrometric measurements, both in situ and in laboratory, as well as radon measurements in the seawater were performed. Activity concentrations and the associated dose rates due to naturally occurring (232)Th, (238)U and (40)K radioisotopes were determined. Dose rates calculated from in situ gamma spectrometry are in correlation with dose rates calculated from activity concentrations measured in collected samples of pebbles and rocks. In situ gamma ray spectrometry in the seawater has been performed, showing activity concentration of 220 and 240 Bq m(-3) for (214)Bi and (214)Pb, respectively due to the presence of magmatic rocks in the seabed. The radium equivalent activity varied from 13 to 53 Bq kg(-1). These values are lower than the limit values, indicating that the radiation hazard is not significant. The highest mean activity concentrations of naturally occurring radionuclides in rock samples collected were found on the islands of magmatic origin. PMID:20085897

  13. Time correlation of cosmic-ray-induced neutrons and gamma rays at sea level

    NASA Astrophysics Data System (ADS)

    Miloshevsky, G.; Hassanein, A.

    2014-02-01

    The neutrons and gamma rays produced by cosmic ray interactions in spallation and evaporation processes of air nuclei are time-correlated. The occurrence of their counts in a fixed time interval is not a random (Poisson) distribution, but rather time-correlated bursts of counts. A computational model is developed to explore time correlations of cosmic-ray-induced background of neutrons and gammas at sea level. Their lifetimes in air showers, multiplicity distributions, coincidence count statistic, and excess variance are analyzed. The effects of latitude and area size on multiplicity and coincidence distributions are also studied. The coincidence count distributions and Feynman-Y statistic are used to reveal the duration of spallation processes and properties of multiplying media. It is found that the coincidence count distribution in fixed time intervals deviates from a Poisson distribution. The Feynman-Y is about an order of magnitude greater for gammas than that for neutrons. For both neutrons and gammas, the duration of time-correlated multiplying processes in air showers is ~250 ?s.

  14. Prediction of radiation dosimetry in patients with thyroid cancer using a Gamma camera

    SciTech Connect

    De Nardo, G.L.; Macey, D.J.; De Nardo, S.J.; Adams, D.A.

    1985-05-01

    Radioiodine in the thyroid or cervical metastases, and therefore radiation dosimetry, can be determined using a probe and phantom. This approach is not ideal for quantitating radioiodine and dosimetry for sites elsewhere in the body. The authors have studied the use of gamma camera methods in association with I-123 to predict the distribution of I-131 and its dosimetry in 3 patients with metastatic thyroid cancer. Images and urine were obtained after administration of tracer I-123 and treatment I-131 to each patient. The geometric mean of counts from anterior and posterior total body camera scans were used to determine body clearance. Organ or metastasis radioactvity and dosimetry were quantitated using planar images and SPECT. Uptake, clearance and dosimetry of structures, such as thyroid and nodular metastases in the lung, could be determined. In summary, a gamma camera method for improved quantitation of radioiodine distribution in the body has been explored. It provides quantitative pharmacokinetics which give better estimates of distribution of radiation dose. This information offers a less empirical approach to the treatment of thyroid cancer with I-131, and other cancers with radiolabeled antibodies.

  15. Influence of gamma radiation on the gel rigidity index and binding capability of gelatin

    SciTech Connect

    Fassihi, A.R.; Parker, M.S.

    1988-10-01

    Changes in the rigidity indices of gelatin gel before and after gamma irradiation were characterized by dynamic mechanical testing, and the significance of these changes on the strength of granules was evaluated. Results illustrate the difficulty of obtaining reproducible values for gels containing less than 20% gelatin. However, rigidity indices for gels with a gelatin content of 20% and higher are consistent and may provide a useful controlling factor for preparation of gelatins of more precise specifications. The data indicate that rigidity degradation kinetics of several concentrations of gelatin gel at different radiation doses are complex, showing both increasing and decreasing rates. These findings strongly suggest that doses of less than 2.0 Mrad of gamma radiation should be used in order to obtain gelatins of acceptable quality for pharmaceutical applications. The crushing strength of granules of lactose powder granulated with irradiated gelatin reveals that the binding capability of such gelatin is significantly reduced. The results obtained for various size fractions and granule hardnesses containing different binder concentrations also suggest that particle size influences the granule strength to a lesser extent than does binder concentration and its consistency.

  16. Radiation damage and charge collection effects in Si(Li) gamma-ray detectors

    NASA Astrophysics Data System (ADS)

    Hull, Ethan L.; Pehl, Richard H.; Tindall, Craig; Luke, Paul N.; Kurfess, James D.

    2003-01-01

    The spectroscopy performance of 6-mm thick Si(Li) planar detectors was studied as a function of operating temperature and electric field. The energy resolution of the 662-keV gamma-ray peak from a 137Cs source was used to monitor the spectroscopy performance of the detectors. The efficiency, depletion voltage, leakage current, and noise were also monitored. The effects of radiation damage caused by 200-MeV protons were studied to determine the viability of operation in space. Four detectors, two maintained at 88 K and two maintained at 212 K, were irradiated to a fluence of 8.7×10 8 p/cm 2. No effects were observed. The two detectors irradiated at 212 K were subsequently irradiated with an additional 8.7×10 9 p/cm 2, again at 212 K. These detectors then exhibited slight energy resolution degradation. No other radiation damage effects were observed. The resolution degradation increased at higher operating temperature and decreased with higher electric field. Cycling the detectors to room temperature for 14 h eliminated the resolution degradation. The resolution of these detectors is limited by the combination of ballistic deficit and parallel noise in the ˜220 K range. A significant decrease in the gamma-ray peak count rate, almost certainly caused by surface channel effects, was the most dramatic temperature-dependent effect observed.

  17. Single-source gamma radiation procedures for improved calibration and measurements in porous media

    SciTech Connect

    Oostrom, M. [Pacific Northwest National Lab., Richland, WA (United States). Environmental Technology Div.] [Pacific Northwest National Lab., Richland, WA (United States). Environmental Technology Div.; Hofstee, C.; Dane, H. [Auburn Univ., AL (United States). Dept. of Agronomy and Soils] [Auburn Univ., AL (United States). Dept. of Agronomy and Soils; Lenhard, R.J. [Sultan Oaboos Univ. (Oman). Dept. of Soil and Water] [Sultan Oaboos Univ. (Oman). Dept. of Soil and Water

    1998-08-01

    When dual-energy gamma radiation systems are employed for measurements in porous media, count rates from both sources are often used to compute parameter values. However, for several applications, the count rates of just one source are insufficient. These applications include the determination of volumetric liquid content values in two-liquid systems and salt concentration values in water-saturated porous media. Single-energy gamma radiation procedures for three applications are described in this paper. Through an error analysis, single-source procedures are shown to reduce the probable error in the determinations considerably. Example calculations and simple column experiments were conducted for each application to compare the performance of the new single-source and standard dual-source methods. In all cases, the single-source methods provided more reliable data than the traditional dual-source methods. In addition, a single-source calibration procedure is proposed to determine incident count rates indirectly. This procedure, which requires packing under saturated conditions, can be used in all single- and dual-source applications and yields accurate porosity and dry bulk density values.

  18. The effect of perinatal sup 60 Co gamma radiation on brain weight in beagles

    SciTech Connect

    Hamilton, B.F.; Benjamin, S.A.; Angleton, G.M.; Lee, A.C. (Colorado State Univ., Fort Collins (USA))

    1989-08-01

    Beagle dogs were given single, whole-body {sup 60}Co gamma-radiation exposures at one of three prenatal (8, 28, or 55 days postcoitus) or three postnatal (2, 70, or 365 days postpartum) ages to evaluate the relative radiosensitivity of various stages of brain development. A total of 387 dogs received mean doses ranging from 0.16 to 3.83 Gy, and 120 dogs were sham-irradiated. Groups of dogs were sacrificed at preselected times from 70 days to 11 years of age. Brain weight decreased significantly with increasing dose in dogs irradiated at 28 or 55 days postcoitus or at 2 days postpartum. Irradiations at 28 days postcoitus were dramatically more effective in causing a reduction in brain weight than those at 55 days postcoitus or 2 days postpartum. Among dogs given 1.0 Gy or more and followed for up to 4 years, there was a radiation effect evident at all three sensitive exposure ages. Among dogs given lower doses and followed for up to 11 years, there was a significant decrease in brain weight in dogs given 0.80-0.88 Gy at 28 days postcoitus. All decreases in brain weight were present after normalization for radiation-induced reductions in skeletal (body) size. No specific morphologic changes were noted in the brains which showed the radiation-related reductions in size.

  19. Radiation hardness of plastic scintillating fiber against fast neutron and gamma -ray irradiation

    Microsoft Academic Search

    Akira Murakami; Hideki Yoshinaka; Minehiko Goto

    1993-01-01

    In future collider experiments, where a background radiation level is estimated to be very high, e.g. around 10[sup 2] [approximately] 10[sup 5] Gy\\/yr and 10[sup 11] [approximately] 10[sup 14] n\\/cm[sup 2]\\/yr at SSC, the detectors operating around the collision point in the experiments will encounter a considerable amount of radiation. Therefore, the detectors, especially the calorimeter, are required to be

  20. Effects of gamma radiation on hard dental tissues of albino rats using scanning electron microscope – Part 1

    Microsoft Academic Search

    Nabil El-Faramawy; Reham Ameen; Khaled El-Haddad; Ahmed Maghraby; Medhat El-Zainy

    2011-01-01

    In the present study, 40 adult male albino rats were used to study the effect of gamma radiation on the hard dental tissues (enamel surface, dentinal tubules and the cementum surface). The rats were irradiated at 0.2, 0.5, 1.0, 2.0, 4.0 and 6.0 Gy gamma doses. The effects of irradiated hard dental tissues samples were investigated using a scanning electron microscope.

  1. Radiative B Meson Decay as a Probe of Physics Beyond the Standard Model: Time-Dependent CP Violation in B0 --> KS pi0 gamma and the B --> phi K gamma Branching Fraction

    SciTech Connect

    Tuggle, Joseph Marion, IV; /Maryland U.; ,

    2009-01-22

    The author presents measurements of radiative B meson decays to the final states K{sub s}{sup 0}{pi}{sup 0}{gamma} and K{phi}{gamma} based on data collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at SLAC. In a data sample of 467 million B{bar B} pairs, the time-dependent CP asymmetry in B{sup 0} {yields} K{sub s}{sup 0}{pi}{sup 0}{gamma} decays is measured in two regions of K{sub s}{sup 0}-{pi}{sup 0} invariant mass. In the K* region, 0.8 < m(K{sub s}{sup 0}{pi}{sup 0}) < 1.0 GeV/c{sup 2}, we find S{sub K*{gamma}} = -0.03 {+-} 0.29 {+-} 0.03 and C{sub K*{gamma}} = -0.14 {+-} 0.16 {+-} 0.03; in the range 1.1 < m(K{sub s}{sup 0}{pi}{sup 0}) < 1.8 GeV/c{sup 2}, they find S{sub K{sub s}{sup 0}{pi}{sup 0}{gamma}} = -0.78 {+-} 0.59 {+-} 0.09 and C{sub K{sub s}{sup 0}{pi}{sup 0}{gamma}} = -0.36 {+-} 0.33 {+-} 0.04. With a sample of 228 million B{bar B} pairs they measure the branching fraction {Beta}(B{sup +} {yields} K{sup +}{phi}{gamma}) = (3.5 {+-} 0.6 {+-} 0.4) x 10{sup -6} and set the limit {Beta}(B{sup 0} {yields} K{sup 0}{phi}{gamma}) < 2.7 x 10{sup -6} at 90% confidence level. The direct CP asymmetry in B{sup +} {yields} K{sup +}{phi}{gamma} is found to be A{sub CP} = (-26 {+-} 14 {+-} 5)%. In each case the uncertainties are statistical and systematic, respectively.

  2. Pilot scale-up and shelf stability of hydrogel wound dressings obtained by gamma radiation

    NASA Astrophysics Data System (ADS)

    Soler, Dulce María; Rodríguez, Yanet; Correa, Hector; Moreno, Ailed; Carrizales, Lila

    2012-08-01

    This study is aimed of producing pilot batches of hydrogel wound dressings by gamma radiation and evaluating their shelf stability. Six batches of 3L capacity were prepared based on poly(vinyl pyrrolidone), agar and polyethylene glycol and they were dispensed in polyester trays, covered with polyester films and sealed in two types of materials: polyethylene bags and vacuum polyethylene bags. Dressings were formed in a single step process for the hydrogel formation and sterilization at 25-30 kGy gamma radiation dose in a JS-9500 Gamma Irradiator (Nordion, Canada). The six batches were initially physicochemical characterized in terms of dimensions and appearance, gel fraction, morphology analysis, hydrogel strength, moisture retention capability and swelling capacity. They were kept under two storage conditions: room temperature (T: 30±2 °C/RH: 70± 5%) and refrigerated temperature (T: 5±3 °C) during 24 months and sterility test was performed. The appearance of membranes was transparent, clear, uncut and flexible; the gel fraction of batches was higher than 75% and the hydrogel surface showed a porous structure. There was a slow decrease of the compression rate 20% until 7 h and about 70% at 24 h. Moisture retention capability in 5 h was similar for all the batches, about 40% and 60% at 37 °C and at room temperature respectively. The swelling of hydrogels in acidic media was strong and in alkaline media the weight variation remains almost stable until 24 h and then there is a loss of weight. The six batches remained sterile during the stability study in the conditions tested. The pilot batches were consistent from batch to batch and remained stable during 24 months.

  3. Cell membrane oxidative damage induced by gamma-radiation and apoptotic sensitivity.

    PubMed

    Mishra, Kaushala P

    2004-01-01

    Ionizing radiation-generated reactive oxygen species (ROS) resulting in oxidative damage to the cell membrane and its consequent role in the mechanism of apoptotic cell death have been receiving growing attention in cellular radiobiology. In recent years, evidence has accumulated to suggest that it is the damage to the cell membrane that contributes to the radiation cell killing. It has been demonstrated that degradation of membrane-bound sphingomyelinase (SMase) after irradiation of bovine endothelial cell produces ceramide, which initiates an apoptotic cascade, suggesting membrane-triggered events in the mechanism of cellular apoptosis. Fluorescence and electron spin resonance (ESR) studies from gamma-irradiation ofliposomal vesicles have shown that radiation-mediated lipid damage was modified by the inclusion of structure-modulating agents (e.g., cholesterol) and antioxidants (e.g., tocopherol, eugenol). The magnitude of the modification of the damage was found to be dependent on the concentration of these modifiers. Moreover, experiments on dipalmitoyl phosphatidyl choline (DPPC) unilamellar liposomes demonstrated a biphasic behavior of radiation damage, which was remarkably modified by ascorbic acid and alpha-tocopherol in a concentration-dependent fashion. The comparison of their protective effects showed that ascorbic acid was less effective than tocopherol against radiation damage to liposomes. Studies on irradiated mouse thymocytes employing FDA fluorescence probe have suggested post-irradiation time- and dose-dependent changes in membrane permeability. The determination of induction of apoptosis in irradiated thymocytes showed a time-dependent DNA fragmentation, suggesting that radiation-induced permeability changes and occurrence of apoptotic death in thymocytes were closely correlated. These results are discussed, with an emphasis on membrane-damage-mediated apoptotic death with relevance to improvement of cancer radiotherapy. PMID:14994996

  4. Indoor radon-daughter concentration and gamma radiation in urban and rural homes on geologically varying ground.

    PubMed

    Tell, I; Jönsson, G; Bensryd, I; Attewell, R; Skerfving, S; Strömberg, U

    1993-01-29

    The radon (Rn)-daughter level (track film, 3 months) was lower in 129 urban than in 197 rural houses (geometric means, (GM) 18 versus 40 Bq/m3; P < 0.001; range 3-416). In rural dwellings higher levels were found in those built over deposits of alum shale occurrences (P = 0.04; 12 on porous glaciofluvial cover 94 Bq/m3; 127 others 43 Bq/m3; significant interaction, P = 0.01), than in 158 others (37 Bq/m3). There was no systematic effect of the type of water supply, neither of indoor smoking. One hundred twenty three homes with a complete cellar were lower than 200 with no or part cellar (18 versus 40 Bq/m3; P < 0.001). There was only a weak association between log-transformed gamma radiation (GM 10, range 33-50 microR/h) and Rn-daughter levels (r = 0.18; 95% confidence interval 0.07-0.28). Our results show the importance for indoor Rn-daughter levels of the bedrock and cover beneath the house, and the need for Rn-daughter measurements in epidemiological studies. PMID:8424158

  5. 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.

  6. Using RADFET for the real-time measurement of gamma radiation dose rate

    NASA Astrophysics Data System (ADS)

    Andjelkovi?, Marko S.; Risti?, Goran S.; Jakši?, Aleksandar B.

    2015-02-01

    RADFETs (RADiation sensitive Field Effect Transistors) are integrating ionizing radiation dosimeters operating on the principle of conversion of radiation-induced threshold voltage shift into absorbed dose. However, one of the major drawbacks of RADFETs is the inability to provide the information on the dose rate in real-time using the conventional absorbed dose measurement technique. The real-time monitoring of dose rate and absorbed dose can be achieved with the current mode dosimeters such as PN and PIN diodes/photodiodes, but these dosimeters have some limitations as absorbed dose meters and hence they are often not a suitable replacement for RADFETs. In that sense, this paper investigates the possibility of using the RADFET as a real-time dose rate meter so that it could be applied for simultaneous online measurement of the dose rate and absorbed dose. A RADFET sample, manufactured by Tyndall National Institute, Cork, Ireland, was tested as a dose rate meter under gamma irradiation from a Co-60 source. The RADFET was configured as a PN junction, such that the drain, gate and source terminals were grounded, while the radiation-induced current was measured at the bulk terminal, whereby the bulk was successively biased with 0?, 10?, 20? and 30?V. In zero-bias mode the radiation-induced current was unstable, but in the biased mode the current response was stable for the investigated dose rates from 0.65? to 32.1?Gy?h?1 and up to the total absorbed dose of 25?Gy. The current increased with the dose rate in accordance with the power law, whereas the sensitivity of the current read-out was linear with respect to the applied bias voltage. Comparison with previously analyzed PIN photodiodes has shown that the investigated RADFET is competitive with PIN photodiodes as a gamma radiation dose rate meter and therefore has the potential to be employed for the real-time monitoring of the dose rate and absorbed dose.

  7. TeV Gamma Rays from BL Lac Objects due to Synchrotron Radiation of Extremely High Energy Protons

    E-print Network

    F. A. Aharonian

    2000-11-18

    One of remarkable features of the gamma ray blazar Markarian 501 is the reported shape of the TeV spectrum, which during strong flares of the source remains essentially stable despite dramatic variations of the absolute gamma-ray flux. I argue that this (to a large extent unexpected) behavior of the source could be explained assuming that the TeV gamma-ray emission is a result of synchrotron radiation of extremely high energy protons in highly magnetized compact regions of the jet.

  8. A new analytical formula for neutron capture gamma dose calculations in double-bend mazes in radiation therapy

    PubMed Central

    Ghiasi, Hosein; Mesbahi, Asghar

    2012-01-01

    Background Photoneutrons are produced in radiation therapy with high energy photons. Also, capture gamma rays are the byproduct of neutrons interactions with wall material of radiotherapy rooms. Aim In the current study an analytical formula was proposed for capture gamma dose calculations in double bend mazes in radiation therapy rooms. Materials and methods A total of 40 different layouts with double-bend mazes and a 18 MeV photon beam of Varian 2100 Clinac were simulated using MCNPX Monte Carlo (MC) code. Neutron capture gamma ray dose equivalent was calculated by the MC method along the maze and at the maze entrance door of all the simulated rooms. Then, all MC resulted data were fitted to an empirical formula for capture gamma dose calculations. Wu–McGinley analytical formula for capture gamma dose equivalent at the maze entrance door in single-bend mazes was also used for comparison purposes. Results For capture gamma dose equivalents at the maze entrance door, the difference of 2–11% was seen between MC and the derived equation, while the difference of 36–87% was found between MC and the Wu–McGinley methods. Conclusion Our results showed that the derived formula results were consistent with the MC results for all of 40 different geometries. However, as a new formula, further evaluations are required to validate its use in practical situations. Finally, its application is recommend for capture gamma dose calculations in double-bend mazes to improve shielding calculations. PMID:24377027

  9. Gamma

    NSDL National Science Digital Library

    The Geometric Algorithms for Modeling, Motion, and Animation (GAMMA) research group is part of the Department of Computer Science at the University of North Carolina. Some of the topics of research include haptics, "robot motion planning," collision detection, and "real-time interaction with virtual environments." There are several projects that are described in detail for each of the main areas of investigation. Many recent papers are offered that describe the progress and findings of the group's research. Additionally, there is a large collection of videos demonstrating computer animation, simulation, and interactive applications. Some software can also be downloaded for the GAMMA Web site; however, access to a few of the titles must first be approved by the system administrator.

  10. Characterization of an Escherichia coli mutant (radB101) sensitive to. gamma. and uv radiation, and methyl methanesulfonate

    Microsoft Academic Search

    N. J. Sargentini; K. C. Smith

    1983-01-01

    After N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis of Escherichia coli K-12 (xthA14), an X-ray-sensitive mutant was isolated. This sensitivity is due to a mutation, radB101, which is located at 56.5 min on the E.coli K-12 linkage map. The radB101 mutation sensitized wild-type cells to ..gamma.. and uv radiation, and to methyl methanesulfonate. When known DNA repair-deficient mutants were ranked for their ..gamma..-radiation sensitivity relative

  11. 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.

  12. Determination of radiative neutron capture cross sections for unstable nuclei by the {gamma}-ray strength function method

    SciTech Connect

    Utsunomiya, H.; Goriely, S. [Department of Physics, Konan University, Okamoto 8-9-1, Higashinada, Kobe 658-8501 (Japan); Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, Campus de la Plaine, CP-226, 1050 Brussels (Belgium)

    2012-11-12

    An indirect method referred to as the {gamma}-ray strength function method has been devised to determine radiative neutron capture cross sections for unstable nuclei along the valley of {beta}-stability. This method is based on the {gamma}-ray strength function which interconnects radiative neutron capture and photoneutron emission within the statistical model. The method was applied to several unstable nuclei such as {sup 93,95}Zr, {sup 107}Pd, and 121,123Sn. This method offers a versatile application extended to unstable nuclei far from the stability when combined with Coulomb dissociation experiments at RIKEN-RIBF and GSI.

  13. Measurement of Branching Fractions in Radiative BDecays to eta K gamma and Search for B Decays to eta' K gamma

    SciTech Connect

    Aubert, B.

    2006-03-31

    The authors present measurements of the B {yields} {eta}K{gamma} branching fractions and upper limits for the B {yields} {eta}'K{gamma} branching fractions. For B{sup +} {yields} {eta}K{sup +}{gamma} they also measure the time-integrated charge asymmetry. The data sample, collected with the BABAR detector at the Stanford Linear Accelerator Center, represents 232 x 10{sup 6} produced B{bar B} pairs. The results for branching fractions and upper limits at 90% C.L. in units of 10{sup -6} are: {Beta}(B{sup 0} {yields} {eta}K{sup 0}{gamma}) = 11.3{sub -2.6}{sup +2.8} {+-} 0.6, {Beta}(B{sup +} {yields} {eta}K{sup +}{gamma}) = 10.0 {+-} 1.3 {+-} 0.5, {Beta}(B{sup 0} {yields} {eta}'K{sup 0}{gamma}) < 6.6, {Beta}(B{sup +} {yields} {eta}'K{sup +}{gamma}) < 4.2. The charge asymmetry in the decay B{sup +} {yields} {eta}K{sup +}{gamma} is {Alpha}{sub ch} = -0.09 {+-} 0.12 {+-} 0.01. The first errors are statistical and the second systematic.

  14. Caffeine enhanced measurement of mutagenesis by low levels of [gamma]-irradiation in human lymphocytes

    SciTech Connect

    Puck, T.P.; Johnson, R.; Waldren, C.A. (Eleanor Roosevelt Institute for Cancer Research, Denver, CO (United States)); Morse, H. (Univ. of Colorado Cancer Center, Denver, CO (United States))

    1993-09-01

    The well-known action of caffeine in synergizing mutagenesis (including chromosome aberrations) of agents like ionizing radiation by inhibition of cellular repair processes has been incorporated into a rapid procedure for detection of mutagenicity with high sensitivity. Effects of 5-10 rads of [gamma]-irradiation, which approximate the human lifetime dose accumulation from background radiation, can be detected in a two-day procedure using an immortalized human WBC culture. Chromosomally visible lesions are scored on cells incubated for 2 h after irradiation in the presence and absence of 1.0 mg/ml of caffeine. An eightfold amplification of scorable lesions is achieved over the action of radiation alone. This approach provides a closer approximation to absolute mutagenicity unmitigated by repair processes, which can vary in different situations. It is proposed that mutagenesis testing of this kind, using caffiene or other repair-inhibitory agents, be employed to identify mutagens in their effective concentrations to which human populations may be exposed; to detect agents such as caffeine that may synergize mutagenic actions and pose epidemiologic threats; and to discover effective anti-mutagens. Information derived from the use of such procedures may help prevent cancer and newly acquired genetic disease.

  15. Review on the production process and uses of controlled rheology polypropylene—Gamma radiation versus electron beam processing

    NASA Astrophysics Data System (ADS)

    Lugão, A. B.; Otaguro, H.; Parra, D. F.; Yoshiga, A.; Lima, L. F. C. P.; Artel, B. W. H.; Liberman, S.

    2007-11-01

    Controlled rheology polypropylene grades are established commodities in the polymer processing market. However, new types, mainly the so-called high melt strength polypropylene (HMSPP) grades, are being introduced in the last two decades and radiation processing has played an important role. The melt strength properties of a polymer increases with molecular weight and with long-chain branching due to the increase in the entanglement level. As polypropylene (PP) is a linear polymer, the way to improve its elongational viscosity is by the production of a bi-modal polymer. Basell's patents claim the production of long-chain branching on PP by irradiating with electrons under oxygen free atmosphere, followed by two heating steps to allow radical recombination and annihilation reaction. Some other companies have issued patents using electron beam processing, but so far there is no actual production other than the Basell one. As a result of a research joint effort, IPEN, BRASKEM (the biggest Brazilian polymer producer) and EMBRARAD (the major Brazilian radiation processing center) developed a new process to produce HMSPP based on gamma processing. This paper will address some characteristics of each technology and the main industrial opportunities.

  16. Measurement of $K^- p$ radiative capture to $\\gamma \\Lambda$ and $\\gamma \\Sigma^0$ for $p_{K^-}$ between 514 and 750 MeV/$c$

    E-print Network

    Prakhov, S; Phaisangittisakul, N; Nefkens, B M K; Allgower, C E; Bekrenev, V; Briscoe, W J; De Cruz, L; Isenhower, D; Knecht, N; Koulbardis, A; Kozlenko, N; Kruglov, S; Lolos, G; Lopatin, I; Manley, D M; Maruši?, A; McDonald, S; Olmsted, J; Papandreou, Z; Peaslee, D; Price, J W; Ryckebusch, J; Sadler, M; Shafi, A; Starostin, A; Staudenmaier, H M; Strakovsky, I I; Supek, I; Van Cauteren, T

    2009-01-01

    Differential cross sections for $K^-$ radiative capture in flight on the proton, leading to the $\\gamma\\Lambda$ and $\\gamma\\Sigma^0$ final states, have been measured at eight $K^-$ momenta between 514 and 750 MeV/$c$. The data were obtained with the Crystal Ball multiphoton spectrometer installed at the separated $K/\\pi$ beam line C6 of the BNL Alternating Gradient Synchrotron. The results substantially improve the existing experimental data available for studying radiative decays of excited hyperon states. An exploratory theoretical analysis is performed within the Regge-plus-resonance approach. According to this analysis, the $\\gamma\\Sigma^0$ final state is dominated by hyperonresonance exchange and hints at an important role for a resonance in the mass region of 1700 MeV. In the $\\gamma\\Lambda$ final state, on the other hand, the resonant contributions account for only half the strength, and the data suggest the importance of a resonance in the mass region of 1550 MeV.

  17. Deep levels and radiation effects in p-InP

    NASA Technical Reports Server (NTRS)

    Anderson, W. A.; Singh, A.; Jiao, K.; Lee, B.

    1989-01-01

    A survey was conducted on past studies of hole traps in InP. An experiment was designed to evaluate hole traps in Zn-doped InP after fabrication, after electron irradiation and after annealing using deep level transient spectroscopy. Data similar to that of Yamaguchi was seen with observation of both radiation-induced hole and electron traps at E sub A=0.45 eV and 0.03 eV, respectively. Both traps are altered by annealing. It is also shown that trap parameters for surface-barrier devices are influenced by many factors such as bias voltage, which probes traps at different depths below the surface. These devices require great care in data evaluation.

  18. Annihilation radiation from a hot e/+/-e/-/ plasma. [gamma ray bursts

    NASA Technical Reports Server (NTRS)

    Ramaty, R.; Meszaros, P.

    1981-01-01

    The radiation from electron-positron annihilations in a plasma of temperature above 10 to the 8th K is investigated as a possible source of the emission line at energies between 400 and 460 keV frequently seen in gamma-ray bursts. The annihilation rate and luminosity of an optically thin electron-positron plasma and the energy distribution of the resulting annihilation radiation are calculated by the use of a Monte Carlo technique as functions of temperature. Results indicate the annihilation spectrum to be peaked at an energy of 0.511 MeV plus a temperature-dependent blueshift, and the annihilation line to be significantly temperature-broadened. The widths of the observed burst emission lines set an upper limit of 3 x 10 to the 8th K on the temperature of any pair annihilation region in burst sources, which is considerably lower than the typical kinetic temperatures of the radiating particles. It is thus inferred that either the annihilation region is nonthermal, or spatially distinct from the burst site.

  19. Effect of Gamma Radiation on Optical and EPR Absorption Spectra of Phosphate and Fluoride Glasses Containing Lead

    Microsoft Academic Search

    T. V. Bocharova; G. O. Karapetyan

    2005-01-01

    The induced optical and EPR absorption spectra of phosphate and fluoride glasses containing lead are investigated. It is revealed\\u000a that exposure to gamma radiation leads to the formation of radiation-induced defects responsible for the induced absorption\\u000a band with a maximum at 12500–13500 cm?1 and the EPR signal in the form of an almost symmetric line with a g factor of

  20. Protective value of elevated levels of gamma interferon in serum against exoerythrocytic stages of Plasmodium falciparum.

    PubMed Central

    Deloron, P; Chougnet, C; Lepers, J P; Tallet, S; Coulanges, P

    1991-01-01

    In vitro experiments suggested that gamma interferon, CD8+ T cells, and anticircumsporozoite antibodies inhibited the exoerythrocytic stages of malaria parasites. To assess the role played in vivo by these factors, we conducted a prospective study in Madagascar. Forty individuals with a negative blood smear were followed for 8 weeks to detect the appearance of parasites in blood. Nineteen subjects remained negative for malaria, whereas 21 individuals became positive during follow-up. Among these, seven presented with blood parasites within the first 2 weeks and were excluded, as they probably were infected by sporozoites at enrollment. When measured at enrollment, antibodies to the synthetic peptide (NANP)5, lymphocyte proliferation with (NANP)5, and various lymphocytes subsets were similar among individuals that later presented with a Plasmodium falciparum blood infection or were not infected. Conversely, the level of gamma interferon in serum was higher in individuals that did not present with a P. falciparum infection during follow-up. These data suggest that gamma interferon may inhibit the malaria exoerythrocytic stages of development under in vivo conditions, as it does in vitro. PMID:1774292

  1. Influence of gamma radiation on the physicochemical and rheological properties of sterculia gum polysaccharides

    NASA Astrophysics Data System (ADS)

    Singh, Baljit; Sharma, Vikrant

    2013-11-01

    Keeping in view the influence of gamma radiation on the physiochemical properties of the polysaccharides and their importance in the food and pharmaceutical industry, in the present study attempt has been made to investigate the effects of absorbed dose on FTIR, XRD, SEMs, absorbance, pH, solubility, water absorption capacity, emulsion stability and rheology of sterculia gum. Increase in solubility and decrease in swellability of gum has been observed on increasing the absorbed dose. The emulsion stability has improved for the gum sample irradiated with total dose of 8.1±0.2 kGy. Apparent viscosity of gum solution first increased with increase in dose from 0 to 8.1±0.2 kGy than decreased with regular trends with further increase in total absorbed dose. Flow behavior of gum solution shifted to Newtonian from non-Newtonian with increasing the dose.

  2. Finger injury from over-exposure to an industrial gamma radiation source.

    PubMed

    Sahin, Cihan; Cesur, Ceyhun; Sever, Celalettin; Eren, Fikret

    2015-03-01

    The aim of this paper was to report a rare cause of radionecrosis and its long-term results. Iridium-192 ((192)Ir) is commonly used for radiography as a gamma ray source to locate flaws in welds and metal components in gas and oil industry. A 38-year-old man was subjected to radiation unintentionally. One month after the exposure wounds were appeared on the second and third fingers, and they were treated by conventional wound care and hyperbaric oxygen therapy. However wounds were relapsed one year later that brought the patient to us. The wounds were treated by wound care and hyperbaric oxygen therapy. When the patient was brought to us one year later the result was interesting. The third finger's pulp (there was not any wound one year before) was contracted and one third of the distal phalanx was exposed. PMID:25249387

  3. Effect of gamma — radiation on vicine and convicine in broad beans ( Vicia faba L. )

    NASA Astrophysics Data System (ADS)

    Jaddou, H.

    Broad bean ( Vicia faba L. ) is considered to be a good source of protein. The presence of vicine and convicine and their role as a causative agents of favism limited their use. The effect of gamma radiation from 60Co source was tested on solutions of a mixture of vicine and convicine. Analysis was carried out using spectrophotometric method. Reduction of 92% in vicine and convicine was observed when a dose of 10.0 kGy was used. The reduction was very much lower when powdered dry beans was irradiated. Research in progress in order to attain a higher destructive effect. Further chemical and biological studies are also required to follow up this effect.

  4. Composition, temperature and radiation induced changes in gamma irradiated AAAMPS copolymer

    NASA Astrophysics Data System (ADS)

    Rao, B. S.; Indira, S.; Sridhar, V.; Punnaiah, G.; Babu, B. S.; Subbakrishna, C.

    2005-06-01

    Effect of composition, temperature and radiation dose in gamma irradiated acrylamide-2-acrylamido-2-methyl propane sulphonic acid (AA) copolymer has been investigated by electron spin resonance (ESR) and fourier transform infrared (FTIR) techniques. ESR spectra of gamma irradiated AA copolymer have been recorded under different conditions. The observed ESR spectra are analysed by computer simulation techniques, to separate the constituent component spectra. Magnetic parameters employed to simulate the component spectra enabled the identification of corresponding free radicals. The AA copolymer with low acrylamide content composed of macroradicals of the type -CH2-CH-CH2- and methyl radicals (CH3) whereas the copolymer with high acryl amide content possess methyl radicals and radicals of the type -CH2-C(CONH2)-CH2-/CH3-C-CH3. Reasons for the variation in the formation of free radicals have been explained. The observed changes in ESR spectra of irradiated AA copolymer at higher temperatures are thought to be due to the recombination of free radicals. Formation of free radicals found to be enhanced with the increase in dose of irradiation. FTIR spectra of pure and irradiated copolymers have also confirmed the previous results.

  5. Fabrication and mechanical characterization of biodegradable and synthetic polymeric films: Effect of gamma radiation

    NASA Astrophysics Data System (ADS)

    Akter, Nousin; Khan, Ruhul A.; Salmieri, Stephane; Sharmin, Nusrat; Dussault, Dominic; Lacroix, Monique

    2012-08-01

    Chitosan (1 wt%, in 2% aqueous acetic acid solution) and starch (1 wt%, in deionised water) were dissolved and mixed in different proportions (20-80 wt% chitosan) then films were prepared by casting. Tensile strength and elongation at break of the 50% chitosan containing starch-based films were found to be 47 MPa and 16%, respectively. It was revealed that with the increase of chitosan in starch, the values of TS improved significantly. Monomer, 2-butane diol-diacrylate (BDDA) was added into the film forming solutions (50% starch-based), then casted films. The BDDA containing films were irradiated under gamma radiation (5-25 kGy) and it was found that strength of the films improved significantly. On the other hand, synthetic petroleum-based polymeric films (polycaprolactone, polyethylene and polypropylene) were prepared by compression moulding. Mechanical and barrier properties of the films were evaluated. The gamma irradiated (25 kGy) films showed higher strength and better barrier properties.

  6. FY06 Annual Report: Amorphous Semiconductors for Gamma Radiation Detection (ASGRAD)

    SciTech Connect

    Johnson, Bradley R.; Riley, Brian J.; Crum, Jarrod V.; Sundaram, S. K.; Henager, Charles H.; Zhang, Yanwen; Shutthanandan, V.

    2007-01-01

    We describe progress in the development of new materials for portable, room-temperature, gamma-radiation detection at Pacific Northwest National Laboratory at the Hanford Site in Washington State. High Z, high resistivity, amorphous semiconductors are being designed for use as solid-state detectors at near ambient temperatures; principles of operation are analogous to single-crystal semiconducting detectors. Amorphous semiconductors have both advantages and disadvantages compared to single crystals, and this project is developing methods to mitigate technical problems and design optimized material for gamma detection. Several issues involved in the fabrication of amorphous semiconductors are described, including reaction thermodynamics and kinetics, the development of pyrolytic coating, and the synthesis of ingots. The characterization of amorphous semiconductors is described, including sectioning and polishing protocols, optical microscopy, X-ray diffraction, scanning electron microscopy, optical spectroscopy, particle-induced X-ram emission, Rutherford backscattering, and electrical testing. Then collaboration with the University of Illinois at Urbana-Champaign is discussed in the areas of Hall-effect measurements and current voltage data. Finally, we discuss the strategy for continuing the program.

  7. SIFTER: Scintillating Fiber Telescopes for Energetic Radiation, Gamma-Ray Applications

    NASA Technical Reports Server (NTRS)

    Paciesas, William S.

    2002-01-01

    The research project "SIFTER: Scintillating Fiber Telescopes for Energetic Radiation, Gamma-Ray Applications" approved under the NASA High Energy Astrophysics Research Program. The principal investigator of the proposal was Prof. Geoffrey N. Pendleton, who is currently on extended leave from UAH. Prof. William S. Paciesas administered the grant during Dr. Pendleton's absence. The project was originally funded for one year from 6/8/2000 to 6/7/2001. Due to conflicts with other commitments by the PI, the period of performance was extended at no additional cost until 6/30/2002. The goal of this project was to study scintillating fiber pair-tracking gamma-ray telescope configurations specifically designed to perform imaging and spectroscopy in the 5 - 250 MeV energy range. The main efforts were concentrated in two areas: 1) development of tracking techniques and event reconstruction algorithms, with particular emphasis on angular resolution; and 2) investigation of coded apertures as a means to improve the instrument angular resolution at low energies.

  8. Effect of radiation on solid paracetamol: ESR identification and dosimetric features of gamma-irradiated paracetamol

    NASA Astrophysics Data System (ADS)

    Polat, M.; Korkmaz, M.

    2006-01-01

    In the present work, electron spin resonance (ESR) identification of gamma-irradiated paracetamol and its potential use as a normal and/or accidental dosimetric material were investigated in the dose range of 2.5-25 kGy. Both unirradiated paracetamol and mechanically ground vermidon samples exhibited a weak single resonance line at g = 2.0049 +/- 0.0006 and had Delta H-pp = 0.6 +/- 0.02 mT. Gamma irradiation produced an increase in signal intensity with a small hyperfine splitting in both paracetamol and vermidon and many weak resonance lines on both sides of a central line in the case of vermidon. Dose-response curves associated with central line of paracetamol and vermidon were found to follow polynomial and linear function, respectively. Simulation calculations based on the room temperature ESR intensity data of the paracetamol sample irradiated at 10 kGy were performed to determine the structure and spectral parameters of the radiation-induced radical species involved in the formation of the experimental ESR spectrum of paracetamol.

  9. Radioactivity Levels and Gamma-Ray Dose Rate in Soil Samples from Kohistan (Pakistan) Using Gamma-Ray Spectrometry

    Microsoft Academic Search

    M. Khan Hasan; M. Ismail; K. Khan; P. Akhter

    2011-01-01

    The analysis of naturally occurring radionuclides (226Ra, 232Th and 40K) and an anthropogenic radionuclide 137Cs is carried out in some soil samples collected from Kohistan district of N.W.F.P. (Pakistan), using gamma-ray spectrometry. The gamma spectrometry is operated using a high purity Germanium (HPGe) detector coupled with a computer based high resolution multi channel analyzer. The specific activity in soil ranges

  10. Shield optimization program. Part 4: Effects of neutron and gamma-ray radiations from nuclear weapons on SDI weapon platforms

    Microsoft Academic Search

    M. S. Smith; J. O. Johnson; T. A. Gabriel; J. M. Barnes; J. D. Drischler; R. T. Santoro

    1989-01-01

    Initial studies have been completed to estimate the radiation induced damage in silicon based electronic components onboard a representative Space Based Interceptor (SBI) weapon platform. The SBI weapon platform model used in the studies represents the author's concept of such a system. The analysis was completed for neutrons and gamma rays emanating from a nuclear weapon detonation in space. Results

  11. Cytological investigation of the effects of gamma radiation on cotton seeds with partial removal of the damaging effects

    Microsoft Academic Search

    Atakuziev

    1973-01-01

    The efficiency of the use of high and low temperatures for the partial ; reduction of the damaging effects of gamma radiation was tested on air-dried ; cotton seed of 108-F and S-4727 varieties of Gossypium hirsutum L. The seeds were ; irradiated with doses of 10, 40, and 80 kR at doses of 810 R\\/min. The seeds were ;

  12. INFLUENCE OF GAMMA RADIATION ON THERMAL PROPERTIES AND WATER VAPOR TRANSMISSION OF POLY(3- HYDROXYBUTYRATE) (PHB) IN BLENDS

    Microsoft Academic Search

    Pedro L. Forster; Natália A. Martins; Duclerc F. Parra

    2009-01-01

    Biodegradable polymers are a newly emerging field. A vast number of biodegradable polymers have been synthesized recently and some microorganisms and enzymes capable of degrading them have been identified. Polyesters such as poly(3-hydroxybutyrate) (PHB) or other polyhydroxyalkanoates (PHAs) have attracted commercial and academic interest as new biodegradable materials. In this work, we investigated the effect of gamma radiation on the

  13. A Novel Detector for Measuring Gamma-Ray Fluxes in a Mixed Pulsed Neutron-Gamma Radiation Fields

    Microsoft Academic Search

    Xiaoping Ouyang; Zhongbing Zhang; Qunshu Wang

    2007-01-01

    An ICI (insulator-conductor-insulator) gamma-ray detector designed for measurement of fast rising, high intensity pulsed gamma-ray fluxes has been developed. Like vacuum Compton diode (VCD) and dielectric Compton diode (DCD) devices, the ICI detector operates by utilization of the Compton effect. It has a very fast time response (rise time is less than 1 ns), a large linearity and a wide

  14. 2004 Progress Report for Grant No. DE-FG03-03NA00076 Nuclear Level Densities and Gamma-ray Strength Functions: Stewardship Sciences Academic Alliances Program

    SciTech Connect

    G. E. Mitchell

    2004-10-18

    To verify the apparent large enhancement of the radiative strength function in light and medium nuclei, the 56Fe(n,2gamma)57Fe reaction was measured. The two-step cascade intensities with soft primary intensities confirm the enhancement. The combined results have been published in Physical Review Letters and featured in the Physics News Update. Data for the Yb isotopes have been combined to examine the systematics of level densities and strength function in three Yb isotopes. A paper on these results have been accepted for publication in Physical Review C. Analysis of the gamma rays from neutron induced reactions on 48Ti have been measured and analyzed for neturon energies from 1 to 250 MeV.

  15. High energy gamma ray astronomy

    NASA Technical Reports Server (NTRS)

    Fichtel, C. E.

    1974-01-01

    The SAS-2 gamma ray experiment and its detection of celestial gamma rays are described. Data also cover intensity of high energy gamma rays, gamma ray distribution, gamma ray origin, and diffuse radiation.

  16. A comparison of radiation damage in liner ICs from cobalt-60 gamma rays and 2.2-MeV electrons

    NASA Technical Reports Server (NTRS)

    Gauthier, M. K.; Nichols, D. K.

    1983-01-01

    The total ionizing dose response of fourteen IC types from eight manufacturers was measured using Co-60 gamma rays and 2.2-MeV electrons for exposure levels of 100 to 20,000 Gy(Si). Key parameter measurements were made and compared for each device type. The data show that a Co-60 source is not a suitable simulation source for some systems because of the generally more damaging nature of electrons as well as the unpredictable nature of the individual device response to the two types of radiations used here.

  17. Determination of environmental radiation flux and organ doses using in-situ gamma spectroscopy

    NASA Astrophysics Data System (ADS)

    Al-Ghamdi, Abdulrahman S.

    Contamination of buildings represent a unique problem during Decontamination and Decommissioning (D&D) of nuclear facilities. It is necessary to determine the long-lived radionuclides and their respective specific activities in building materials before the right D&D decision can be made. At the same time, radiation risk of workers or potential occupants in the facility must be assessed as part of the D&D process. The goal of this project was to develop a methodology of obtaining gamma radiation flux and organ doses from in-situ gamma spectroscopy. Algorithms were developed to simulate the response functions of the HPGe detector and to convert the spectra into photon fluences. A Monte Carlo code, MCNP4C, was used to simulate HPGe detector response and to develop the conversion algorithm. The simulated spectra obtained for an HPGe detector were converted to flux using the algorithm for various different geometries. The response functions of the detector are presented in this document for the gamma energies from 60 keV to 2.2 MeV. Published fluence-to-dose conversion coefficients were used to calculate organ doses and effective dose equivalent. We then tested the theory at a 100-MeV linear electron accelerator at Rensselaer Polytechnic Institute (RPI). Samples of the activated concrete walls and floor in the target room of the Linac facility as well as some steel samples were taken to quantify the specific activities of the structures. The results show that the most important long-lived radionuclides include 22 Na, 46Sc, 54 Mn, 57Co, 60 Co, 65Zn, 152 Eu and 154Eu, depending on the location and composition of the material. The specific activities at the Linac facility range from 1.15E-01 to 765.31 muCi/Kg. The annual effective dose equivalent was assessed to be 2.44 mSv y-1 (0.244 rem y-1 ), which is about 5% of the Annual EDE limits to workers.

  18. Gamma-ray spectroscopy in the decay of (83)Se to levels of (83)Br.

    PubMed

    Krane, K S

    2015-03-01

    High-resolution ? ray spectroscopy experiments have been done to study the emissions from the radioactive decay of 22-min (83g)Se produced from neutron capture using samples of enriched (82)Se. Energy and intensity values have been obtained to roughly an order of magnitude greater precision than in previous studies. Based on energy sums, 2 new levels are proposed in the daughter (83)Br and one previously proposed level is shown to be doubtful. Some 25 new transitions appear to decay with the (83)Se halflife, about half of which can be accommodated among the previous or newly proposed levels. Several previous ? ray placements are shown to be inconsistent with the new determinations of the (83)Br energy levels, but cannot be accommodated anywhere else among the known levels. As a result of the missing ? ray placements, some of the ? branchings in the decay to levels of (83)Br appear to be negative. Gamma rays from the 2.4-h decay of the daughter (83)Br to levels of (83)Kr have also been observed, along with decays of (81g)(,m)Se present as a small impurity in the enriched samples and also as a strong component in irradiated samples of natural Se. PMID:25527896

  19. ESR study of vacancy clusters produced by radiation damage in silicon and barium oxide. [Neutrons; gamma radiation

    SciTech Connect

    Yousif, H.N.

    1983-01-01

    The results of a study of defect cluster formation in two totally different insulating crystals; purely covalent silicon and highly ionic barium oxide are reported here. Elementary models of radiation damage in silicon relate the net defect production only to the total energy deposited in the lattice (Kinchin-Pease hypothesis). This hypothesis has been tested by monitoring electron spin resonance (ESR) signals of several dominant cluster defects, in high purity and in oxygen contaminated samples irradiated with two very different reactor spectra. The hypothesis fails. In neutron irradiated BaO crystals, a new paramagnetic defect is introduced by a sequence of annealing and gamma irradiation. It has been identified as belonging to adjacent barium and oxygen vacancies with a single trapped electron. Analysis of the hyperfine interactions with the five near neighbor bariums gives rise to a detailed interpretation of the electron wave function as that of a weakly perturbed F/sup +/ center in the electric field of the barium vacancy. A defect model is proposed to account for the hyperfine interactions. The defect is shown to be formed by thermally activated migration of the barium vacancy, with an activation energy of 1.26 +/- 0.15 eV.

  20. Measurement of Inclusive Radiative B -Meson Decay B -> X_s gamma

    SciTech Connect

    Ozcan, V.E.; /SLAC /Stanford U., Appl. Phys. Dept.

    2006-01-06

    Radiative decays of the B meson, B {yields} X{sub s}{gamma}, proceed via virtual flavor changing neutral current processes that are sensitive to contributions from high mass scales, either within the Standard Model of electroweak interactions or beyond. In the Standard Model, these transitions are sensitive to the weak interactions of the top quark, and relatively robust predictions of the inclusive decay rate exist. Significant deviation from these predictions could be interpreted as indications for processes not included in the minimal Standard Model, like interactions of charged Higgs or SUSY particles. The analysis of the inclusive photon spectrum from B {yields} X{sub s}{gamma} decays is rather challenging due to high backgrounds from photons emitted in the decay of mesons in B decays as well as e{sup +}e{sup -} annihilation to low mass quark and lepton pairs. Based on 88.5 million B{bar B} events collected by the BABAR detector, the photon spectrum above 1.9 GeV is presented. By comparison of the first and second moments of the photon spectrum with QCD predictions (calculated in the kinetic scheme), QCD parameters describing the bound state of the b quark in the B meson are extracted: m{sub b} = (4.45 {+-} 0.16) GeV/c{sup 2}; {mu}{sub {pi}}{sup 2} = (0.65 {+-} 0.29) GeV{sup 2}. These parameters are useful input to non-perturbative QCD corrections to the semileptonic B decay rate and the determination of the CKM parameter |V{sub ub}|. Based on these parameters and heavy quark expansion, the full branching fraction is obtained as: {Beta}(B {yields} X{sub s}{gamma}){sup E{sub {gamma}}>1.6 GeV} = (4.05 {+-} 0.32(stat) {+-} 0.38(syst) {+-} 0.29(model)) x 10{sup -4}. This result is in good agreement with previous measurements, the statistical and systematic errors are comparable. It is also in good agreement with the theoretical Standard Model predictions, and thus within the present errors there is no indication of any interactions not accounted for in the Standard Model. This finding implies strong constraints on physics beyond the Standard Model.

  1. Influence of shielding certain parts of the body on the course of radiation sickness in dogs with total gamma irradiation

    NASA Technical Reports Server (NTRS)

    Razgovorov, B. L.; Konnova, N. I.

    1973-01-01

    In an experiment on dogs which were subjected to total gamma irradiation at lethal doses, the influence of shielding the head and the anterior part of the stomach on the clinical course and outcome of radiation sickness was studied. The experiment results supported the basic data obtained in experiments on small laboratory animals and showed the high effectiveness of shielding a part of the body in dogs. In protecting various masses of tissue with shieldings that provided equal attenuation of the radiation and with an equal dose of radiation, shielding of parts of the anterior portion of the stomach was much more effective than shielding the head.

  2. Regulation of cysteine dioxygenase and gamma-glutamylcysteine synthetase is associated with hepatic cysteine level.

    PubMed

    Lee, Jeong-In; Londono, Monica; Hirschberger, Lawrence L; Stipanuk, Martha H

    2004-02-01

    Two hepatic enzymes, cysteine dioxygenase (CDO) and gamma-glutamylcysteine synthetase (GCS), play important regulatory roles in the response of cysteine metabolism to changes in dietary sulfur amino acid or protein levels. To examine the time-course of changes in CDO and GCS activities, CDO and GCS-catalytic or heavy subunit protein and mRNA levels, and cysteine and glutathione levels, we adapted rats to either a low protein (LP) or high protein (HP) diet, switched them to the opposite diet, and followed these parameters over 6 days. Hepatic CDO activity and amount, but not mRNA level, increased in response to higher protein intake; the t(1/2) of change for CDO activity or protein level was 22 h for rats switched from a LP to a HP diet and 8 h for rats switched from a HP to a LP diet, suggesting that the HP diet decreased turnover of CDO. Hepatic GCS activity, catalytic subunit amount and mRNA level decreased in response to a higher protein intake. GCS catalytic subunit level changed with a similar t(1/2) for both groups, but the change in GCS activity in rats switched from a LP diet to a HP diet was faster (approximately 16h) than for rats switched from a HP to a LP diet (approximately 74h). Hepatic cysteine and glutathione levels reached new steady states within 12 h (LP to HP) or 24 h (HP to LP). CDO activity appeared to be regulated at the level of protein, probably by diminished turnover of CDO in response to higher protein intake or cysteine level, whereas GCS activity appeared to be regulated both at the level of mRNA and activity state in response to the change in cysteine or protein availability. These findings support a role of cysteine concentration as a mediator of its own metabolism, favoring catabolism when cysteine is high and glutathione synthesis when cysteine is low. PMID:14972351

  3. Study of Optical Absorption in Gamma Irradiated Glass for Radiation Dosimetry Purpose

    SciTech Connect

    Farah, K.; Mejri, A. [Laboratoire de Radiotraitement, Centre National des Sciences et Technologies Nucleaires. 2020 Sidi-Thabet (Tunisia); Ben Ouada, H. [Laboratoire de Physique et Chimie des Interfaces, Faculte des Sciences de Monastir, 5000 (Tunisia)

    2007-09-19

    Optical absorption investigation in a silicate glass before and after gamma irradiation was performed in the range 350-800 nm to study the induced colour centres to evaluate this potential as radiation-sensitive material for dose measurements. The radiation induced bands are observed around 410 and 600 nm leading. The intensities of the overall absorption spectra are observed to increase progressively with increasing doses between 1 and 1200 kGy. The influence of isothermal annealing on the formation and the decay of the induced colour centres has been investigated. The activation energy characteristic of the annealing process was calculated from Arrhenius equation. The obtained values are equal to 0.251 and 0.310 eV for the 410 nm band and 0.261 and 0.353 eV for the 600 nm one. The similarity of these values for both bands suggests that the related optical transitions correspond to the same type of Non-Bridging-Oxygen Hole Centres (NBOHCs): ({identical_to}Si-O deg.) in different configurations.

  4. High doses of gamma radiation suppress allergic effect induced by food lectin

    NASA Astrophysics Data System (ADS)

    Vaz, Antônio F. M.; Souza, Marthyna P.; Vieira, Leucio D.; Aguiar, Jaciana S.; Silva, Teresinha G.; Medeiros, Paloma L.; Melo, Ana M. M. A.; Silva-Lucca, Rosemeire A.; Santana, Lucimeire A.; Oliva, Maria L. V.; Perez, Katia R.; Cuccovia, Iolanda M.; Coelho, Luana C. B. B.; Correia, Maria T. S.

    2013-04-01

    One of the most promising areas for the development of functional foods lies in the development of effective methods to reduce or eliminate food allergenicity, but few reports have summarized information concerning the progress made with food irradiation. In this study, we investigated the relationship between allergenicity and molecular structure of a food allergen after gamma irradiation and evaluate the profile of the allergic response to irradiated allergens. Cramoll, a lectin isolated from a bean and used as a food allergen, was irradiated and the possible structural changes were accompanied by spectrofluorimetry, circular dichroism and microcalorimetry. Subsequently, sensitized animals subjected to intragastric administration of non-irradiated and irradiated Cramoll were treated for 7 days. Then, body weight, leukocytes, cytokine profiles and histological parameters were also determined. Cramoll showed complete inhibition of intrinsic activity after high radiation doses. Changes in fluorescence and CD spectra with a simultaneous collapse of the tertiary structure followed by a pronounced decrease of native secondary structure were observed after irradiation. After oral challenge, sensitized mice demonstrate an association between Cramoll intake, body weight loss, eosinophilia, lymphocytic infiltrate in the gut and Eotaxin secretion. Irradiation significantly reduces, according to the dose, the effects observed by non-irradiated food allergens. We confirm that high-dose radiation may render protein food allergens innocuous by irreversibly compromising their molecular structure.

  5. Analysis of gamma radiation from a radon source: Indications of a solar influence

    NASA Astrophysics Data System (ADS)

    Sturrock, P. A.; Steinitz, G.; Fischbach, E.; Javorsek, D.; Jenkins, J. H.

    2012-08-01

    This article presents an analysis of about 29,000 measurements of gamma radiation associated with the decay of radon in a sealed container at the Geological Survey of Israel (GSI) Laboratory in Jerusalem between 28 January 2007 and 10 May 2010. These measurements exhibit strong variations in time of year and time of day, which may be due in part to environmental influences. However, time-series analysis reveals a number of periodicities, including two at approximately 11.2 year-1 and 12.5 year-1. We have previously found these oscillations in nuclear-decay data acquired at the Brookhaven National Laboratory and at the Physiklisch-Technische Bundesanstalt, and we have suggested that these oscillations are attributable to some form of solar radiation that has its origin in the deep solar interior. A curious property of the GSI data is that the annual oscillation is much stronger in daytime data than in nighttime data, but the opposite is true for all other oscillations. This may be a systematic effect but, if it is not, this property should help narrow the theoretical options for the mechanism responsible for decay-rate variability.

  6. Characterization of methyl methacrylate grafting onto preirradiated biodegradable lignocellulose fiber by gamma-radiation.

    PubMed

    Khan, Ferdous

    2005-01-14

    Gamma-radiation-induced graft copolymerization of methyl methacrylate onto natural lignocellulose (jute) fiber was carried out by the preirradiation method in an aqueous medium by using octylphenoxy-polyethoxyethanol as an emulsifier. The different factors that influenced the graft copolymer reaction process were investigated. In the case of radiation-dose-dependent grafting, samples irradiated in the presence of air produced up to 73% graft weight compared to 53% obtained in the case of irradiation in a nitrogen environment. By assuming Arrhenius reaction kinetics, the activation energy (E(a)) of the grafting reaction process was evaluated for different reaction temperatures. Moreover, the graft copolymer reaction was controlled by incorporating a homopolymer-inhibiting agent and three different chain-transfer agents in the reaction medium. The mechanical and thermal properties of jute fiber 'as received' and jute-graft-poly(methyl methacrylate) were also investigated. The results showed that the percentage of grafting with jute fiber has a significant effect on the properties. The kinetic parameters were evaluated from TGA thermograms by using Broido's method in the temperature range 240-350 degrees C. Scanning electron micrographs show that the structural changes on the surface of jute fibers were induced by graft copolymerization of methyl methacrylate monomer. Fiber-fiber surface friction was measured in terms of the average maximum load and the kinetic friction. SEM of jute-graft-poly(methyl methacrylate). PMID:15635719

  7. Signature of gravitational wave radiation in afterglows of short gamma-ray bursts?

    NASA Astrophysics Data System (ADS)

    Fan, Yi-Zhong; Wu, Xue-Feng; Wei, Da-Ming

    2013-09-01

    Short gamma-ray bursts (GRBs), brief intense emission of ? rays characterized by a duration shorter than 2 s that are plausibly powered by the coalescence of binary neutron stars, are believed to be strong gravitational wave radiation (GWR) sources. The test of such a speculation has been thought to be impossible until the performance of the detectors like advanced LIGO. Recently there has been growing evidence for the formation of a highly magnetized neutron star (i.e., magnetar) in the double neutron star mergers. In this work we reexamine the interpretation of the x-ray plateau followed by an abrupt decline detected in some short GRB afterglows within the supramassive magnetar model and find that the maximum gravitational mass of the nonrotating neutron stars is ˜2.3M? and the observed duration of some x-ray plateaus are significantly shorter than that expected in the magnetic dipole radiation scenario, suggesting that the collapse of the supramassive magnetars has been considerably enhanced by the energy loss via GWR. Such a result demonstrates that the signature of GWR may have already existed in current electromagnetic data of short GRBs.

  8. Inhaled ²³⁹PuOâ and\\/or total-body gamma radiation: Early mortality and morbidity in rats and dogs

    Microsoft Academic Search

    R. E. Filipy; J. R. Decker; Y. L. Lai; K. E. Lauhala; R. L. Buschbom; M. P. Hiastala; D. R. McGee; J. F. Park; E. G. Kuffel; H. A. Ragan; W. C. Cannon; S. S. Yaniv; B. R. Scott

    1988-01-01

    Rats and beagle dogs were given doses of ⁶°Co gamma radiation and\\/or body burdens of ²³⁹PuOâ within lethal ranges in an experiment to determine and compare morbidity and mortality responses of both species within 1 year after exposure. Radiation-induced morbidity was assessed by measuring changes in body weights, hematologic parameters, and pulmonary-function parameters. Gamma radiation caused transient morbidity, reflected by

  9. Combination of gamma radiation and essential oils from medicinal plants in managing Tribolium castaneum contamination of stored products.

    PubMed

    Ahmadi, Mehrdad; Abd-alla, Adly Mohamed M; Moharramipour, Saeid

    2013-08-01

    Effectiveness of management of insect infestation of stored products with essential oils as viable alternatives to synthetic insecticides can be enhanced with gamma radiation. We studied effects of sublethal doses of essential oils from Rosmarinus officinalis (L.) and Perovskia atriplicifolia (Benth) (safe natural insecticides) in combination with gamma radiation on mortality of adults of Tribolium castaneum (Herbst). The insects were subjected to two radiation doses and two concentrations of the essential oils in the air. This combined treatment increased the mortality, which was also 3-6 times higher than could be expected from the sum of the effects of each of the treatments. The synergistic effect was more pronounced in the case of R. officinalis (L.) than in the case of P. atriplicifolia (Benth). The experiments have shown that the known insecticidal effectiveness of the essential oils can be enhanced by preliminary irradiation. Possible approaches to implementation of the combined treatment are discussed. PMID:23632647

  10. Low-Dose Gamma-Radiation Inhibits Benzo[A]Pyrene-Induced Lung Adenoma Development in A/J Mice

    PubMed Central

    Bruce, Veronica R.; Belinsky, Steven A.; Gott, Katherine; Liu, Yushi; March, Thomas; Scott, Bobby; Wilder, Julie

    2012-01-01

    Low-dose ionizing radiation (LDR) may lead to suppression of smoking-related lung cancer. We examined the effects of a known cigarette smoke carcinogen Benzo[a]pyrene (B[a]P) alone or in combination with fractionated low-dose gamma radiation (60 – 600 mGy total dose) on the induction of lung neoplasms in the A/J mouse. Our results show that 600 mGy of gamma radiation delivered in six biweekly fractions of 100 mGy starting 1 month after B[a]P injection significantly inhibits the development of lung adenomas per animal induced by B[a]P. Our data also indicated that the six biweekly doses suppressed the occurrence of spontaneous hyperplastic foci in the lung, although this suppression failed to reach statistical significance when analyzed as average foci per lung possibly related to the small sample sizes used for the control and test groups. PMID:23304102

  11. EXPLORING THE RELATION BETWEEN (SUB-)MILLIMETER RADIATION AND {gamma}-RAY EMISSION IN BLAZARS WITH PLANCK AND FERMI

    SciTech Connect

    Leon-Tavares, J.; Tornikoski, M.; Laehteenmaeki, A. [Aalto University Metsaehovi Radio Observatory, Metsaehovintie 114, FIN-02540 Kylmaelae (Finland); Valtaoja, E. [Tuorla Observatory, Department of Physics and Astronomy, University of Turku, 20100 Turku (Finland); Giommi, P.; Polenta, G.; Gasparrini, D.; Cutini, S., E-mail: leon@kurp.hut.fi [ASI Science Data Center, ASDC c/o ESRIN, via G. Galilei, 00044 Frascati (Italy)

    2012-07-20

    The coexistence of Planck and Fermi satellites in orbit has enabled the exploration of the connection between the (sub-)millimeter and {gamma}-ray emission in a large sample of blazars. We find that the {gamma}-ray emission and the (sub-)mm luminosities are correlated over five orders of magnitude, L{sub {gamma}}{proportional_to}L{sub (sub-)mm}. However, this correlation is not significant at some frequency bands when simultaneous observations are considered. The most significant statistical correlations, on the other hand, arise when observations are quasi-simultaneous within two months. Moreover, we find that sources with an approximate spectral turnover in the middle of the mm-wave regime are more likely to be strong {gamma}-ray emitters. These results suggest a physical relation between the newly injected plasma components in the jet and the high levels of {gamma}-ray emission.

  12. GRABGAM: A Gamma Analysis Code for Ultra-Low-Level HPGe SPECTRA

    SciTech Connect

    Winn, W.G.

    1999-07-28

    The GRABGAM code has been developed for analysis of ultra-low-level HPGe gamma spectra. The code employs three different size filters for the peak search, where the largest filter provides best sensitivity for identifying low-level peaks and the smallest filter has the best resolution for distinguishing peaks within a multiplet. GRABGAM basically generates an integral probability F-function for each singlet or multiplet peak analysis, bypassing the usual peak fitting analysis for a differential f-function probability model. Because F is defined by the peak data, statistical limitations for peak fitting are avoided; however, the F-function does provide generic values for peak centroid, full width at half maximum, and tail that are consistent with a Gaussian formalism. GRABGAM has successfully analyzed over 10,000 customer samples, and it interfaces with a variety of supplementary codes for deriving detector efficiencies, backgrounds, and quality checks.

  13. ZZ{gamma} and Z{gamma}{gamma} couplings at linear e{sup +}e{sup -} collider energies with the effects of Z polarization and initial state radiation

    SciTech Connect

    Atag, S.; Sahin, I. [Department of Physics, Faculty of Sciences, Ankara University, 06100 Tandogan, Ankara (Turkey)

    2004-09-01

    The constraints on the neutral gauge boson couplings, ZZ{gamma} and Z{gamma}{gamma}, are investigated at linear e{sup +}e{sup -} collider energies through the Z{gamma} production with longitudinal and transverse polarization states of the final Z boson. Because of high energy of linear electron-positron beams, initial state radiation (ISR) considerably changes the production cross section. We obtain an increase in the cross section by a factor of 2-3 due to ISR for transverse polarization and by a factor of 10-100 for longitudinal polarization states depending on the energy. We find the 95% C.L. limits on the CP conserving form factors h{sub 3}{sup Z}, h{sub 4}{sup Z}, h{sub 3}{sup {gamma}}, and h{sub 4}{sup {gamma}} with integrated luminosity 500 fb{sup -1} and {radical}(s)=0.5,1,1.5 TeV energies. It is shown that the longitudinal polarization of the Z boson, together with ISR, can improve sensitivities by factors 2-3.

  14. Inhaled /sup 239/PuO/sub 2/ and/or total-body gamma radiation: Early mortality and morbidity in rats and dogs

    SciTech Connect

    Filipy, R.E.; Decker, J.R.; Lai, Y.L.; Lauhala, K.E.; Buschbom, R.L.; Hiastala, M.P.; McGee, D.R.; Park, J.F.; Kuffel, E.G.; Ragan, H.A.; Cannon, W.C.; Yaniv, S.S.; Scott, B.R.

    1988-08-01

    Rats and beagle dogs were given doses of /sup 60/Co gamma radiation and/or body burdens of /sup 239/PuO/sub 2/ within lethal ranges in an experiment to determine and compare morbidity and mortality responses of both species within 1 year after exposure. Radiation-induced morbidity was assessed by measuring changes in body weights, hematologic parameters, and pulmonary-function parameters. Gamma radiation caused transient morbidity, reflected by immediately depressed blood cell concentrations and by long-term loss of body weight and diminished pulmonary function in animals of both species that survived the acute gamma radiation syndrome. Inhaled plutonium caused a loss of body weight and diminished pulmonary function in both species, but its only effect on blood cell concentrations was lymphocytopenia in dogs. Combined gamma irradiation and plutonium lung burdens were synergistic, in that animals receiving both radiation insults had higher morbidity and mortality rates than would be predicted based on the effect of either kind of radiation alone. Plutonium lung burdens enhanced the effect of gamma radiation in rats within the first 30 days of exposure, and gamma radiation enhanced the long-term effect of plutonium lung burdens in both species. Rats were less sensitive to both kinds of radiation, whether administered alone or in combination. 71 refs., 105 figs., 48 tabs.

  15. Exposure to indoor radon and natural gamma radiation in some workplaces at Algiers, Algeria.

    PubMed

    Aït Ziane, M; Lounis-Mokrani, Z; Allab, M

    2014-07-01

    Radon activity concentrations have been measured in 34 workplaces throughout Algiers nuclear research centre, in Algeria, during some periods between March 2007 and June 2013 using Electret ion chambers, nuclear tracks detectors and an AlphaGuard system. The indoor radon levels range from 2 to 628 Bq m(-3) with an average indoor concentration equals to 92 Bq m(-3), whereas the estimated outdoor radon concentrations range from 2 to 14 Bq m(-3) with an average value of 6 Bq m(-3). This study also focused on parameters affecting radon concentration levels such as ?oor number, ventilation and atmospheric parameters. Furthermore, the mean gamma rates have been measured in the different investigated locations and have been found to be varying between 33 and 3300 nSv h(-1). The annual effective dose for workers calculated using the appropriate equilibrium and occupancy factors is lower than the value recommended by International Commission on Radiological Protection in its Publication 103. PMID:24711531

  16. IFN-{gamma}+ CD8+ T Lymphocytes: Possible Link Between Immune and Radiation Responses in Tumor-Relevant Hypoxia

    SciTech Connect

    De Ridder, Mark [Radiotherapie, Oncologisch Centrum, UZ Brussel, Brussels (Belgium); Cancer Research Unit, Vrije Universiteit Brussel, Brussels (Belgium)], E-mail: mark.deridder@uzbrussel.be; Jiang Heng; Esch, Gretel van; Law, Kalun; Monsaert, Christinne [Cancer Research Unit, Vrije Universiteit Brussel, Brussels (Belgium); Berge, Dirk L. van den; Verellen, Dirk; Verovski, Valeri N. [Radiotherapie, Oncologisch Centrum, UZ Brussel, Brussels (Belgium); Storme, Guy A. [Radiotherapie, Oncologisch Centrum, UZ Brussel, Brussels (Belgium); Cancer Research Unit, Vrije Universiteit Brussel, Brussels (Belgium)

    2008-07-01

    Activated T lymphocytes are known to kill tumor cells by triggering cytolytic mechanisms; however, their ability to enhance radiation responses remains unclear. This study examined the radiosensitizing potential of mouse CD8+ T cells, obtained by T-cell-tailored expansion and immunomagnetic purification. Activated CD8+ T cells displayed an interferon (IFN)-{gamma}+ phenotype and enhanced by 1.8-fold the radiosensitivity of EMT-6 tumor cells in 1% oxygen, which modeled tumor-relevant hypoxia. Radiosensitization was counteracted by neutralizing IFN-{gamma} or by blocking the inducible isoform of nitric oxide synthase, thus delineating the immune-tumor cell interaction through the IFN-{gamma} secretion pathway. Reverse transcriptase-polymerase chain reaction, enzyme-linked immunosorbent assay, and fluorescence-activated cell sorter data in agreement detected downregulation of the IFN-{gamma} gene by hypoxia, which caused IFN-{gamma} deficiency next to radioresistance. Therefore, immune and radiation responses are likely to be allied in the hypoxic tumor microenvironment, and CD8+ T cells may bridge immunostimulatory and radiosensitizing strategies.

  17. The influence of {gamma}-ray radiation on electrical properties of CuGaSe{sub 2}

    SciTech Connect

    Kasumoglu, I.; Kerimova, T. G., E-mail: ktaira@physics.ab.az; Mamedova, I. A. [National Academy of Sciences of Azerbaijan, Institute of Physics (Azerbaijan)

    2011-01-15

    The effect of {gamma}-ray radiation on the conductivity of low-resistivity (10{sup 2}2-10{sup 4} {Omega} cm) and high-resistivity (10{sup 5}-10{sup 7} {Omega} cm) CuGaSe{sub 2} single crystals has been studied in the temperature range 77-330 K. It is found that the resistivity of low-resistivity samples increases as the dose of {gamma}-ray radiation is increased, while the resistivity of high-resistivity samples is practically independent of the radiation dose. It is assumed that a decrease in the conductivity of the low-resistivity samples occurs owing to scattering of free charge carriers at defects (charged centers) formed as a result of irradiation with {gamma}-ray photons. It is found that the dose of the {gamma}-ray irradiation does not affect the temperature dependence of resistivity in the low- and high-resistivity samples in the temperature range 77-300 K.

  18. Charged Particle Induced Radiation damage of Germanium Detectors in Space: Two Mars Observer Gamma-Ray Detectors

    NASA Technical Reports Server (NTRS)

    Bruekner, J.; Koenen, M.; Evans, L. G.; Starr, R.; Bailey, S. H.; Boynton W. V.

    1997-01-01

    The Mars Observer Gamma-Ray Spectrometer (MO GRS) was designed to measure gamma-rays emitted by the Martian surface. This gamma-ray emission is induced by energetic cosmic-ray particles penetrating the Martian surface and producing many secondary particles and gamma rays. The MO GRS consisted of an high-purity germanium (HPGe) detector with a passive cooler. Since radiation damage due to permanent bombardment of energetic cosmic ray particles (with energies up to several GeV) was expected for the MO GRS HPGe crystal, studies on radiation damage effects of HPGe crystals were carried on earth. One of the HPGe crystals (paradoxically called FLIGHT) was similar to the MO GRS crystal. Both detectors, MO GRS and FLIGHT, contained closed-end coaxial n-type HPGe crystals and had the same geometrical dimensions (5.6 x 5.6 cm). Many other parameters, such as HV and operation temperature, differed in space and on earth, which made it somewhat difficult to directly compare the performance of both detector systems. But among other detectors, detector FLIGHT provided many useful data to better understand radiation damage effects.

  19. Gamma-ray Flux at Different Levels in the Homestake Mine Measured with NaI detectors

    Microsoft Academic Search

    Dongming Mei; Keenan Thomas; Chao Zhang; Frederick Gray; Jonathan Totushek; Christopher Ruybal

    2009-01-01

    Characterization of various backgrounds is an important step to the design of DUSEL in which the low background experiments are being planned. The gamma-ray flux at the different levels in the Homestake has been measured using three identical NaI detectors arranged as an array. We report the gamma-ray flux in four categories: 1) below 3 MeV, the spectrum is expected

  20. The effects of physicochemical properties on gamma emitting natural radionuclide levels in the soil profile of Istanbul

    Microsoft Academic Search

    Murat Belivermis; Yavuz Çotuk; Sayhan Topcuo?lu

    2010-01-01

    The inventory of gamma-emitting radionuclides was determined in soil samples collected at six depth levels, from 15 locations\\u000a in Istanbul metropolis. The activity concentrations of 232Th, 238U, 40K were measured by means of gamma spectrometry. The average activity concentrations of 232Th, 238U, 40K in the 30-cm depth soil were found as 32.1, 27.4, 393.1 Bq kg???1, respectively. The mean value of

  1. Managing NIF safety equipment in a high neutron and gamma radiation environment.

    PubMed

    Datte, Philip; Eckart, Mark; Jackson, Mark; Khater, Hesham; Manuel, Stacie; Newton, Mark

    2013-06-01

    The National Ignition Facility (NIF) is a 192 laser beam facility that supports the Inertial Confinement Fusion program. During the ignition experimental campaign, the NIF is expected to perform shots with varying fusion yield producing 14 MeV neutrons up to 20 MJ or 7.1 × 10(18) neutrons per shot and a maximum annual yield of 1,200 MJ. Several infrastructure support systems will be exposed to varying high yield shots over the facility's 30-y life span. In response to this potential exposure, analysis and testing of several facility safety systems have been conducted. A detailed MCNP (Monte Carlo N-Particle Transport Code) model has been developed for the NIF facility, and it includes most of the major structures inside the Target Bay. The model has been used in the simulation of expected neutron and gamma fluences throughout the Target Bay. Radiation susceptible components were identified and tested to fluences greater than 10(13) (n cm(-2)) for 14 MeV neutrons and ?-ray equivalent. The testing includes component irradiation using a 60Co gamma source and accelerator-based irradiation using 4- and 14- MeV neutron sources. The subsystem implementation in the facility is based on the fluence estimates after shielding and survivability guidelines derived from the dose maps and component tests results. This paper reports on the evaluation and implementation of mitigations for several infrastructure safety support systems, including video, oxygen monitoring, pressure monitors, water sensing systems, and access control interfaces found at the NIF. PMID:23629064

  2. How gamma radiation processing systems are benefiting from the latest advances in information technology

    NASA Astrophysics Data System (ADS)

    Gibson, Wayne H.; Levesque, Daniel

    2000-03-01

    This paper discusses how gamma irradiation plants are putting the latest advances in computer and information technology to use for better process control, cost savings, and strategic advantages. Some irradiator operations are gaining significant benefits by integrating computer technology and robotics with real-time information processing, multi-user databases, and communication networks. The paper reports on several irradiation facilities that are making good use of client/server LANs, user-friendly graphics interfaces, supervisory control and data acquisition (SCADA) systems, distributed I/O with real-time sensor devices, trending analysis, real-time product tracking, dynamic product scheduling, and automated dosimetry reading. These plants are lowering costs by fast and reliable reconciliation of dosimetry data, easier validation to GMP requirements, optimizing production flow, and faster release of sterilized products to market. There is a trend in the manufacturing sector towards total automation using "predictive process control". Real-time verification of process parameters "on-the-run" allows control parameters to be adjusted appropriately, before the process strays out of limits. Applying this technology to the gamma radiation process, control will be based on monitoring the key parameters such as time, and making adjustments during the process to optimize quality and throughput. Dosimetry results will be used as a quality control measurement rather than as a final monitor for the release of the product. Results are correlated with the irradiation process data to quickly and confidently reconcile variations. Ultimately, a parametric process control system utilizing responsive control, feedback and verification will not only increase productivity and process efficiency, but can also result in operating within tighter dose control set points.

  3. Detection of embedded radiation sources using temporal variation of gamma spectral data.

    SciTech Connect

    Shokair, Isaac R.

    2011-09-01

    Conventional full spectrum gamma spectroscopic analysis has the objective of quantitative identification of all the isotopes present in a measurement. For low energy resolution detectors, when photopeaks alone are not sufficient for complete isotopic identification, such analysis requires template spectra for all the isotopes present in the measurement. When many isotopes are present it is difficult to make the correct identification and this process often requires many trial solutions by highly skilled spectroscopists. This report investigates the potential of a new analysis method which uses spatial/temporal information from multiple low energy resolution measurements to test the hypothesis of the presence of a target spectrum of interest in these measurements without the need to identify all the other isotopes present. This method is referred to as targeted principal component analysis (TPCA). For radiation portal monitor applications, multiple measurements of gamma spectra are taken at equally spaced time increments as a vehicle passes through the portal and the TPCA method is directly applicable to this type of measurement. In this report we describe the method and investigate its application to the problem of detection of a radioactive localized source that is embedded in a distributed source in the presence of an ambient background. Examples using simulated spectral measurements indicate that this method works very well and has the potential for automated analysis for RPM applications. This method is also expected to work well for isotopic detection in the presence of spectrally and spatially varying backgrounds as a result of vehicle-induced background suppression. Further work is needed to include effects of shielding, to understand detection limits, setting of thresholds, and to estimate false positive probability.

  4. Gamma Rays

    MedlinePLUS

    ... Life Decay Chains Radioactive Equilibrium Curies Alpha Particles Beta Particles Gamma Rays Other Decay Modes A gamma ray is a packet of ... energy. It often follows the emission of a beta particle. What happens ... an example of radioactive decay by gamma radiation. When a neutron transforms to ...

  5. Linking Gamma-H2AX Foci and Cancer in Rat Skin Exposed to Heavy Ions and Electron Radiation.

    PubMed

    Burns, Fredric J; Tang, Moon-Shong; Wu, Feng; Schmid, Ernst

    2015-08-01

    This study uses acute doses of three test radiations, [Ar ions (L = 125 keV?), Ne ions (L = 25 keV?) and electron radiation] to examine a potential quantitative link between rat skin cancer induction and gamma-H2AX foci in rat keratinocytes exposed in vitro to radiations with comparable L values. Theory provided a testable link between cancer yield and gamma-H2AX foci yields: YCa(D,L)rat = (NF)2YAX(D,L)keratinocyte (eqn 1), where YCa(D,L) is cancers(rat) at 1.0 y, YAX(D,L) is in vitro gamma-H2AX foci(keratinocyte) , D is radiation dose, L is linear energy transfer, N is irradiated keratinocytes in vivo, and F is the error rate of end joining. An explicit expression for cancer yield was derived based on cancers arising in the ion track region in proportion to D and L (first term) and independently in proportion to D in the delta ray region in between the ion tracks (second term): YCa(D,L) = CCaLD + BCaD (eqn 1a). Parameters quantified include: CCa = 0.000589 ± 0.000150 cancers-micron[rat(kev)Gy]; BCa = 0.0088 ± 0.0035 cancers(ratGy), F = (8.18 ± 0.91) × 10; N = (8.8 ± 1.2) × 10 and (NF)2 = 0.036 ± 0.006 cancer keratinocyte(rat H2AX foci). Verification of eqns (1) and (1a) and the constancy of F support the hypothesis that end-rejoining errors play a major role in radiation carcinogenesis in rat skin. Cancer yields per rat were consistently predictable based on gamma-H2AX foci yields in keratinocytes in vitro such that 27.8 H2AXfoci(keratinocyte) predicted 1.0 cancer(rat) at 1 y. PMID:26107436

  6. Effect of gamma–neutron nuclear reactor radiation on the properties of Bragg gratings written in photosensitive Ge-doped optical fiber

    Microsoft Academic Search

    A. Gusarov; A. Fernandez Fernandez; S. Vasiliev; O. Medvedkov; M. Blondel; F. Berghmans

    2002-01-01

    We have experimentally studied the effect of mixed gamma–neutron nuclear reactor radiation on the effective refractive index of Bragg gratings fabricated in Ge-doped photosensitive optical fiber. We compared the effect of radiation on gratings written with and without hydrogen sensitization and show that the use of hydrogen loading results in an increase of the sensitivity to reactor radiation. Neither grating

  7. Identifying and quantifying radiation damage at the atomic level

    PubMed Central

    Gerstel, Markus; Deane, Charlotte M.; Garman, Elspeth F.

    2015-01-01

    Radiation damage impedes macromolecular diffraction experiments. Alongside the well known effects of global radiation damage, site-specific radiation damage affects data quality and the veracity of biological conclusions on protein mechanism and function. Site-specific radiation damage follows a relatively predetermined pattern, in that different structural motifs are affected at different dose regimes: in metal-free proteins, disulfide bonds tend to break first followed by the decarboxylation of aspartic and glutamic acids. Even within these damage motifs the decay does not progress uniformly at equal rates. Within the same protein, radiation-induced electron density decay of a particular chemical group is faster than for the same group elsewhere in the protein: an effect known as preferential specific damage. Here, B Damage, a new atomic metric, is defined and validated to recognize protein regions susceptible to specific damage and to quantify the damage at these sites. By applying B Damage to a large set of known protein structures in a statistical survey, correlations between the rates of damage and various physicochemical parameters were identified. Results indicate that specific radiation damage is independent of secondary protein structure. Different disulfide bond groups (spiral, hook, and staple) show dissimilar radiation damage susceptibility. There is a consistent positive correlation between specific damage and solvent accessibility. PMID:25723922

  8. Semiphenomenological approximation of the sums of experimental radiative strength functions for dipole gamma transitions of energy E{sub {gamma}}below the neutron binding energy B{sub n} for mass numbers in the range 40 {<=} A {<=} 200

    SciTech Connect

    Sukhovoj, A. M., E-mail: suchovoj@nf.jinr.ru; Furman, W. I., E-mail: furman@nf.jinr.ru; Khitrov, V. A., E-mail: khitrov@nf.jinr.r [Joint Institute for Nuclear Research (Russian Federation)

    2008-06-15

    The sums of radiative strength functions for primary dipole gamma transitions, k(E1) + k(M1), are approximated to a high precision by a superposition of two functional dependences in the energy range 0.5 < E{sub 1} < B{sub n} - 0.5 MeV for the {sup 40}K, {sup 60}Co, {sup 71,74}Ge, {sup 80}Br, {sup 114}Cd, {sup 118}Sn, {sup 124,125}Te, {sup 128}I, {sup 137,138,139}Ba, {sup 140}La, {sup 150}Sm, {sup 156,158}Gd, {sup 160}Tb, {sup 163,164,165}Dy, {sup 166}Ho, {sup 168}Er, {sup 170}Tm, {sup 174}Yb, {sup 176,177}Lu, {sup 181}Hf, {sup 182}Ta, {sup 183,184,185,187}W, {sup 188,190,191,193}Os, {sup 192}Ir, {sup 196}Pt, {sup 198}Au, and {sup 200}Hg nuclei. It is shown that, in any nuclei, radiative strength functions are a dynamical quantity and that the values of k(E1) + k(M1) for specific energies of gamma transitions and specific nuclei are determined by the structure of decaying and excited levels, at least up to the neutron binding energy B{sub n}.

  9. Design of a spreader bar crane-mounted gamma-ray radiation detection system

    NASA Astrophysics Data System (ADS)

    Grypp, Matthew D.; Marianno, Craig M.; Poston, John W.; Hearn, Gentry C.

    2014-04-01

    Over 95% of imports entering the United States from outside North America arrive by sea at 329 ports of entry. These imports are packaged in more than 11 million cargo containers. Radiation portals monitors routinely scan cargo containers leaving port on specially-designed trucks. To accelerate the process, some commercial entities have placed detection systems on the spreader-bar cranes (SBCs) used to offload. Little is known about the radiation background profiles of systems operating on these cranes. To better understand the operational characteristics of these radiation detection systems; a research team from Texas A&M University (TAMU) mounted three thallium-doped sodium iodide [NaI(Tl)] detectors on an SBC at the Domestic Nuclear Detection Office's (DNDO) test track facility at the Port of Tacoma (PoT). These detectors were used to monitor background radiation levels and continuously recorded data during crane operations using a custom-built software package. Count rates and spectral data were recorded for various crane heights over both land and water. The results of this research created a background profile in which count rate was heavily dependent on position demonstrating how detector readings changed in the operational environment.

  10. Protection of cellular DNA from gamma-radiation-induced damages and enhancement in DNA repair by troxerutin.

    PubMed

    Maurya, Dharmendra Kumar; Balakrishnan, Sreedevi; Salvi, Veena Prakash; Nair, Cherupally Krishnan Krishnan

    2005-12-01

    The effect of troxerutin on gamma-radiation-induced DNA strand breaks in different tissues of mice in vivo and formations of the micronuclei were studied in human peripheral blood lymphocytes ex vivo and mice blood reticulocytes in vivo. Treatments with 1 mM troxerutin significantly inhibited the micronuclei induction in the human lymphocytes. Troxerutin protected the human peripheral blood leucocytes from radiation-induced DNA strand breaks in a concentration dependent manner under ex vivo condition of irradiation (2 Gy). Intraperitoneal administration of troxerutin (175 mg/kg body weight) to mice before and after whole body radiation exposure inhibited micronuclei formation in blood reticulocytes significantly. The administration of different doses (75, 125 and 175 mg/kg body weight) of troxerutin 1 h prior to 4 Gy gamma-radiation exposure showed dose-dependent decrease in the yield of DNA strand breaks in murine blood leucocytes and bone marrow cells. The dose-dependent protection was more pronounced in bone marrow cells than in blood leucocytes. Administration of 175 mg/kg body weight of the drug (i.p.) 1 h prior or immediately after whole body irradiation of mice showed that the decrease in strand breaks depended on the post-irradiation interval at which the analysis was done. The observed time-dependent decrease in the DNA strand breaks could be attributed to enhanced DNA repair in troxerutin administered animals. Thus in addition to anti-erythrocytic, anti-thrombic, fibrinolytic and oedema-protective rheological activity, troxerutin offers protection against gamma-radiation-induced micronuclei formation and DNA strand breaks and enhances repair of radiation-induced DNA strand breaks. PMID:16311905

  11. Deinococcus radioresistens sp. nov., a UV and gamma radiation-resistant bacterium isolated from mountain soil.

    PubMed

    Srinivasan, Sathiyaraj; Lee, Jae-Jin; Lim, Sang-Yong; Joe, Min-Ho; Im, Seong-Hun; Kim, Myung Kyum

    2015-02-01

    Two Gram-negative, non-motile, short rod-shaped bacterial strains, designated as 8A(T) and 28A, were isolated from Mount Deogyusan, Jeonbuk Province, South Korea. The isolates were analyzed by a polyphasic approach, revealing variations in their phenotypic characters but high DNA-DNA hybridisation values reciprocally, confirming that they belong to the same species. Both the isolates also showed a high resistance to UV compared with Deinococcus radiodurans, and a gamma-radiation resistance similar to other members of the genus Deinococcus. Phylogenetic analysis with the 16S rRNA gene sequences of closely related species indicated their similarities were below 97 %. Chemotaxonomic data showed the most abundant fatty acids to be C16:1?7c and C16:0. The strains can be distinguished from closely related species by the production of esterase (C4) and ?-galactosidase, and by their ability to assimilate L-alanine, L-histidine and N-acetyl-D-glucosamine. Based on the phenotypic, phylogenetic, and chemotaxonomic data, the isolates represent a novel species of the genus Deinococcus, for which the name Deinococcus radioresistens sp. nov. is proposed. The type strain is 8A(T) (KEMB 9004-109(T) = JCM 19777(T)), and a second strain is 28A (KEMB 9004-113 = JCM 19778). PMID:25515413

  12. Neutron activation analysis, gamma ray spectrometry and radiation environment monitoring instrument concept: GEORAD

    NASA Astrophysics Data System (ADS)

    Ambrosi, R. M.; Talboys, D. L.; Sims, M. R.; Bannister, N. P.; Makarewicz, M.; Stevenson, T.; Hutchinson, I. B.; Watterson, J. I. W.; Lanza, R. C.; Richter, L.; Mills, A.; Fraser, G. W.

    2005-02-01

    Geological processes on Earth can be related to those that may have occurred in past epochs on Mars, if analytical methods used on Earth can be operated remotely on the surface of the Red Planet. Nuclear analytical techniques commonly used in terrestrial geology are neutron activation analysis (NAA) and gamma-ray spectroscopy (GRS), which determine the elemental composition, elemental concentration and stratigraphical distribution of water in rocks and soils. We describe a detector concept called GEORAD (GEOlogical and RADiation environment package) for the proposed ExoMars rover within the ESA's Aurora Programme for the exploration of the Solar System. GEORAD consists of a compact neutron source for the NAA of rocks and soils and a GRS. The GRS has a dual role since it can be used for natural radioactivity studies and NAA. A fully depleted silicon detector coupled to neutron sensitive converters measures the solar particle and neutron flux interacting with the Martian surface. We describe how the GEORAD detector suite could contribute to the geological and biological characterisation of Mars both for the detection of extinct or extant life and to evaluate potential hazards facing future manned missions. We show how GEORAD measurements complement the astrobiological objectives of the Aurora programme.

  13. Mutant quantity and quality in mammalian cells (A{sub L}) exposed to cesium-137 gamma radiation: Effect of caffeine

    SciTech Connect

    McGuinness, S.M.; Shibuya, M.L.; Ueno, A.M. [Colorado State Univ., Fort Collins, CO (United States)] [and others

    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 revealed 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.

  14. 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.

  15. Some Characteristics of the Resistance Transfer Factor (RTF) Episome as Determined by Inactivation with Tritium, P32, and Gamma Radiation

    PubMed Central

    Painter, Robert B.; Ginoza, Herbert S.

    1966-01-01

    The resistance transfer factor (RTF) episome was studied by measuring its inactivation by Co60 gamma radiation, by incorporated P32, and by tritium incorporated as tritium-labeled thymine. The D37 for Co60 irradiation was 7 to 9 × 104 rad. Growth of the bacteria harboring the RTF in BUdR (bromouracil deoxyriboside) increased the sensitivity of the RTF to the gamma radiation. The RTF was markedly inactivated by tritium after growth of the host (thymine requiring) bacteria in tritium-labeled thymine, thus further establishing the presence of thymine in the genome of the RTF. Assuming the efficiency of inactivation by P32 to be 10%, the phosphorus content of the RTF was estimated to be about 2 × 105 P atoms/episome. The data suggest the RTF contains double stranded DNA with a molecular weight of the order of 3 to 8 × 107. PMID:5335449

  16. 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.

  17. Effect of Co-60 gamma radiation on the mechanical properties of epoxy blends and epoxy-graphite fiber interface

    SciTech Connect

    Netravali, A.N.; Manji, A. (Cornell University, Ithaca, NY (USA))

    1991-06-01

    The effect of Co-60 gamma radiation of up to 100 Mrads on an IM6-G graphite fiber-epoxy interface was studied using the single-fiber-composite (SFC) technique. Flexible epoxy blends were formulated using DGEBA based and polyglycol diepoxide epoxies which were cured with aliphatic and aromatic curing agents. Bulk epoxy specimens and graphite fibers were tension tested to obtain their tensile properties. The fragment length distribution from SFC tests, single fiber strength data, and a Monte Carlo simulation of Poisson/Weibull model for fiber strength and flaws were used to obtain the effective interfacial shear strength values. The results indicate that while graphite fiber strength is not affected by radiation, the tensile properties of the epoxies used are adversely affected by the radiation. The interfacial shear strength, however, increases significantly with the radiation dose. 36 refs.

  18. Energy resolution in semiconductor gamma radiation detectors using heterojunctions and methods of use and preparation thereof

    DOEpatents

    Nikolic, Rebecca J.; Conway, Adam M.; Nelson, Art J.; Payne, Stephen A.

    2012-09-04

    In one embodiment, a system comprises a semiconductor gamma detector material and a hole blocking layer adjacent the gamma detector material, the hole blocking layer resisting passage of holes therethrough. In another embodiment, a system comprises a semiconductor gamma detector material, and an electron blocking layer adjacent the gamma detector material, the electron blocking layer resisting passage of electrons therethrough, wherein the electron blocking layer comprises undoped HgCdTe. In another embodiment, a method comprises forming a hole blocking layer adjacent a semiconductor gamma detector material, the hole blocking layer resisting passage of holes therethrough. Additional systems and methods are also presented.

  19. 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 ??Co source. Surviving spores were counted and used to estimate the decimal reduction (D??) value. A dose of 0.2 kGy was sufficient to inactivate 90% of the total recoverable spores from an initial count of 10?- 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 ?-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. PMID:21683605

  20. Combined effect of gamma radiation and Perovskia atriplicifolia for the control of red flour beetle, Tribolium castaneum.

    PubMed

    Ahmadi, M; Moharramipour, S; Mozdarani, H; Negahban, M

    2008-01-01

    In order to explore an effective and safe pesticide that could be coupled up with irradiation method, the present study was conducted to determine the synergistic effects of gamma radiation with an essential oil from Perovskia atriplicifolia (Benth) on Tribolium castaneum (Herbst) as a main stored-product pest. Adult insects were exposed to sub lethal doses of gamma radiation and P. atriplicifolia oil, and the mortality was assessed in a short time period after treatment. There was a significant synergistic effect of exposure to gamma radiation and essential oil on 1-7 days old adults of T. castaneum. The potential toxicity of the essential oil on irradiated adults at 900 Gy was synergistically increased. When irradiated adults were exposed to LD5, LD25 and LD50 values of the oil the mortality was increased 8.5, 13.0 and 16.0 times respectively. This combination of irradiation would have a low environmental impact and high compatibility with P. atriplicifolia. PMID:19226806

  1. Low-level radiation effects on immune cells

    SciTech Connect

    Makinodan, T. [Veterans Administration Medical Center, Los Angeles, CA (United States)

    1995-12-31

    The purpose of this study was to characterize the effects of chronic low-dose ionizing radiation (LDR) on murine immune cells. Previously, it had been reported that LDR enhances the proliferative activity of T cells in vitro and delays the growth of transplantable immunogenic tumors in vivo. This suggests that LDR eliminates immune suppressor cells, which downregulates immune response and/or adoptively upregulates the responsiveness of immune effector cells. It had also been reported that human lymphocytes become refractive to high dose radiation-induced chromosomal aberrations by pretreating mitotically active lymphocytes in vitro with very low doses of ionizing radiation, and the adaptive effect can be abrogated by cycloheximide. This suggests that protein synthesis is required for lymphocytes to respond adoptively to LDR.

  2. The low dose gamma ionising radiation impact upon cooperativity of androgen-specific proteins.

    PubMed

    Filchenkov, Gennady N; Popoff, Eugene H; Naumov, Alexander D

    2014-01-01

    The paper deals with effects of the ionising radiation (?-IR, 0.5 Gy) upon serum testosterone (T), characteristics of testosterone-binding globulin (TeBG) and androgen receptor (AR) in parallel with observation of androgen (A) responsive enzyme activity - hexokinase (HK). The interdependence or relationships of T-levels with parameters of the proteins that provide androgenic regulation are consequently analyzed in post-IR dynamics. The IR-stress adjustment data reveal expediency of TeBG- and AR-cooperativity measurements for more precise assessments of endocrine A-control at appropriate emergencies. PMID:23465891

  3. Radiation reaction at the level of the action

    E-print Network

    Ofek Birnholtz; Shahar Hadar; Barak Kol

    2014-03-12

    The aim of this paper is to highlight a recently proposed method for the treatment of classical radiative effects, in particular radiation reaction, via effective field theory methods. We emphasize important features of the method, and in particular the doubling of fields. We apply the method to two simple systems: for the mass-rope system in 1+1 dimensions we derive an effective action for the mass which describes a damped harmonic oscillator, while for the electromagnetic charge-field system, i.e. the system of an accelerating electric charge in 3+1 d, we derive the leading Abraham-Lorentz-Dirac force.

  4. Effects of low-dose gamma radiation on DNA damage, chromosomal aberration and expression of repair genes in human blood cells

    Microsoft Academic Search

    Wanwisa Sudprasert; Panida Navasumrit; Mathuros Ruchirawat

    2006-01-01

    Exposure to low-dose gamma radiation is common in certain occupations but the biological and health effects from such exposure remain to be determined. The aim of this study was to investigate the effects of low-dose gamma radiation on DNA damage, chromosomal aberration and DNA repair gene expressions in whole blood and peripheral lymphocytes. The study revealed a dose-dependent effect of

  5. Effect of 1. 33 MeV. gamma. radiation and 0. 5 MeV electrons on the mechanical properties of graphite fiber composites

    Microsoft Academic Search

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

    1981-01-01

    Epoxy\\/graphite fiber polymide\\/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; indeed, both electron radiation up to 5000 Mrad and ..gamma.. radiation

  6. Sensory evaluation by gamma radiation effect on protein allergen of laying hen eggs

    NASA Astrophysics Data System (ADS)

    Harder, M. N. C.; Arthur, V.; Perina, V. C. S.; Silva, L. C. A. S.; Bortoleto, G. G.

    2012-08-01

    Although considered the most complete food and nutritionally shown to be part of a healthy diet, the egg is the source of many eating disorders, especially for infants. Irradiation has been used in studies not only as a means of microbiological control, but also on its structural action in the substances molecules and has been used to reduce the allergenic effects. The aim of this study was to evaluate the sensory effects of Co60 gamma radiation on proteins, enabling the acceptability of allergy food for genetically intolerant people. Eggs commercial fresh and freeze-dried and subjected to gamma irradiation by Co60 source at doses 0 (control), 10 kGy; 20 kGy and 30 kGy and rates of doses of 19.4 kGy/h and 31.8 kGy/h. Acceptability test was used by the hedonic scale, since it is necessary to know the "affective status" of consumers for the product, implying a preference, i.e. the most preferred samples are the most accepted and vice versa. The samples were presented as the habit of consumption (cooked) to a group of 41 adults panelists of both gender, aged from 21 to 40 years, and served under complete block design balanced with respect to the order of presentation. The evaluated attributes was flavor, appearance and overall acceptability. In general, for boiled eggs and freeze-dried, it was observed that the control sample was the most acceptable, followed by the sample irradiated with 10 kGy in both dose rates. In addition, panelists presented in testimony that they found interesting changes due to irradiation; also said they would not buy the product because of the marked change in appearance and smell, which at one point he ended up in disgust and detract from sales of the product, but they would buy irradiated with 10 kGy in both dose rate and dose of 20 kGy at a dose rate of 19.4 kGy/h.

  7. Determining the radon exhalation rate from a gold mine tailings dump by measuring the gamma radiation.

    PubMed

    Ongori, Joash N; Lindsay, Robert; Newman, Richard T; Maleka, Peane P

    2015-02-01

    The mining activities taking place in Gauteng province, South Africa have caused millions of tons of rocks to be taken from underground to be milled and processed to extract gold. The uranium bearing tailings are placed in an estimated 250 dumps covering a total area of about 7000 ha. These tailings dumps contain considerable amounts of radium and have therefore been identified as large sources of radon. The size of these dumps make traditional radon exhalation measurements time consuming and it is difficult to get representative measurements for the whole dump. In this work radon exhalation measurements from the non-operational Kloof mine dump have been performed by measuring the gamma radiation from the dump fairly accurately over an area of more than 1 km(2). Radon exhalation from the mine dump have been inferred from this by laboratory-based and in-situ gamma measurements. Thirty four soil samples were collected at depths of 30 cm and 50 cm. The weighted average activity concentrations in the soil samples were 308 ± 7 Bq kg(-1), 255 ± 5 Bq kg(-1) and 18 ± 1 Bq kg(-1) for (238)U, (40)K and (232)Th, respectively. The MEDUSA (Multi-Element Detector for Underwater Sediment Activity) ?-ray detection system was used for field measurements. The radium concentrations were then used with soil parameters to obtain the radon flux using different approaches such as the IAEA (International Atomic Energy Agency) formula. Another technique the MEDUSA Laboratory Technique (MELT) was developed to map radon exhalation based on (1) recognising that radon exhalation does not affect (40)K and (232)Th activity concentrations and (2) that the ratio of the activity concentration of the field (MEDUSA) to the laboratory (HPGe) for (238)U and (40)K or (238)U and (232)Th will give a measure of the radon exhalation at a particular location in the dump. The average, normalised radon flux was found to be 0.12 ± 0.02 Bq m(-2) s(-1) for the mine dump. PMID:25461511

  8. Relationship between Serum Gamma-glutamyl Transferase Levels with Ascending Aortic Dilatation

    PubMed Central

    Kaya, Ahmet; Kaya, Yasemin; Gunaydin, Zeki Yuksel; Enginyurt, Ozgur; Polat, Yavuz Kursat; Topcu, Selim; Saritemur, Murat

    2014-01-01

    Objective: Increased serum gamma-glutamyl transferase levels (GGT) have been shown to directly promote oxidative stress. Previous studies have shown the relationship between the dilatation of the ascending aorta and oxidative stress. This study was designed to examine the relationship between serum GGT concentrations with dilatation of the ascending aorta. Materials and Methods: Ninety patients with ascending aortic dilatation and 90 age-sex-matched patients without aortic dilatation were included in the study. The patients were evaluated by a complete transthoracic echocardiographic examination including measurement of the aortic dimensions, where a diameter of 3.7 cm and above was accepted as ascending aortic dilatation. Serum GGT concentration was measured in all patients. Results: In the group with aortic dilatation, HT frequency, serum uric acid, hs-CRP and GGT levels, the LV mass index, and the left atrial volume index were found to be higher than the control group. The logistic regression analysis showed that only HT frequency (OR:1.23, 95% CI 1.11–1.35, p value: 0.02), the LA volume index (OR: 1.34, 95% CI 1.21±1.4, p:0.005) and serum GGT levels (OR: 1.12, 95% CI 1.01±1.20, p:0.03) were found to be independent predictors. There was a significant correlation between serum GGT levels and ascending aortic diameter (r: 0.268, p<0.001). In the ROC curve analysis, AUC was 0.659 (0.580±0.738) for a 23.5 serum GGT cut-off value (64% sensitivity and 53% specificity). Conclusion: We found that serum GGT concentration was significantly associated with ascending aortic dilatation. Large epidemiological studies are required to correlate the findings from this study with clinical outcome. PMID:25610305

  9. Determination of infrared radiation levels for acute ocular cataractogenesis

    Microsoft Academic Search

    Donald G. Pitts; Anthony P. Cullen

    1981-01-01

    One hundred pigmented rabbit eyes and ten primate eyes were exposed to infrared (IR) radiation in the 715 to 1,400 nm wavelength range and to the full spectrum output from a 5,000 W Xenon high-pressure source. The ocular exposures were evaluated independently with a slitlamp by two researchers and classified for ocular damage.

  10. Blood Cells and Interferon-Gamma Levels Correlation in Latent Tuberculosis Infection

    PubMed Central

    Takenami, Iukary; Loureiro, Camila; Machado, Almério; Emodi, Krisztina; Riley, Lee W.; Arruda, Sérgio

    2013-01-01

    The Mycobacterium tuberculosis (M. tb) infection is largely spread in world’s population. Most infected individuals develop latent tuberculosis infection (LTBI). Tuberculin skin test (TST) and interferon-gamma release assays (IGRAs) are the available tests to detect the infection. It has been reported that some individuals take a longer period of time to develop the infection than others with the same exposure level. It is suggested that the innate immunity, in which neutrophils have an important protective role, is responsible for this. Many hematologic abnormalities have been described as common findings during severe disease. To investigate if these changes are related to LTBI development and if they interfere in TST and IFN-? production, we recruited 88 household contacts of tuberculosis (TB) pulmonary patients and compared blood cell counts with these tests’ results. There were no statistically significant changes in hemoglobin, hematocrit, platelets, global leukocyte, neutrophils, basophils, eosinophils, typical lymphocytes, atypical lymphocytes, and monocytes counts between infected and noninfected individuals. Also, there was no correlation between TST or IGRA and blood cell counts. These results suggest that blood cell counts are not LTBI markers and do not interfere in TST results or IFN-? levels obtained by IGRA. PMID:24040564

  11. Radiation levels in cyclotron-radiochemistry facility measured by a novel comprehensive computerized monitoring system

    NASA Astrophysics Data System (ADS)

    Mishani, E.; Lifshits, N.; Osavistky, A.; Kaufman, J.; Ankry, N.; Tal, N.; Chisin, R.

    1999-04-01

    Radiation levels in a cyclotron-radiochemistry facility were measured during the production of commonly used PET radiopharmaceuticals by a comprehensive computerized monitoring system. The system consists of three major components: on-line radiation monitoring channels, an area control unit, and a gas waste management unit. During production the radiation levels were measured in the cyclotron vault, inside automatic chemistry production and research shielded cells, in the radiochemistry room, in the gas waste decay tank, in the chimney filters, and at the top of the cells chimney. Each detector was calibrated in a known radiation field, and a special detector dead time correction was performed in order to achieve detected signal-to-radiation linearity for the Geiger tubes located in the radiochemistry production and research cells. During production of C-11 and O-15 PET radiopharmaceuticals, high radiation levels were measured in the gas waste decay tank (240 and 80 mR/h, respectively). In contrast, the radiation levels at the chimney filters and at the top of the cells chimney did not exceed the International Atomic Energy Agency (IAEA) Drive Air Concentration (DAC) recommended for C-11 or O-15. During production of FDG, high radiation levels were measured at the chimney filters, however the radiation level at the top of the chimney (3.7 ?Ci/m 3) did not exceed the F-18 DAC recommendation (27 ?Ci/m 3). Low radiation levels of approximately 0.5-1 mR/h were measured in the radiochemistry room during production of PET radiopharmaceuticals. In the cyclotron vault, 2 min after bombardment the radiation levels at 2 m from the cyclotron decreased to 1-2 mR/h. The addition of a gas waste decay system to computerized monitoring channels located near each strategic point of the site allows for a comprehensive survey of the radiochemical processes.

  12. Tritium: a model for low level long-term ionizing radiation exposure

    SciTech Connect

    Carsten, A.L.

    1984-01-01

    The somatic, cytogenetic and genetic effects of single and chronic tritiated water (HTO) ingestion in mice was investigated. This study serves not only as an evaluation of tritium toxicity (TRITOX) but due to its design involving long-term low concentration ingestion of HTO may serve as a model for low level long-term ionizing radiation exposure in general. Long-term studies involved animals maintained on HTO at concentrations of 0.3 ..mu..Ci/ml, 1.0 ..mu..Ci/ml, 3.0 ..mu..Ci/ml or depth dose equivalent chronic external exposures to /sup 137/Cs gamma rays. Maintenance on 3.0 ..mu..Ci/ml resulted in no effect on growth, life-time shortening or bone marrow cellularity, but did result in a reduction of bone marrow stem cells, an increase in DLM's in second generation animals maintained on this regimen and cytogenetic effects as indicated by increased sister chromatid exchanges (SCE's) in bone marrow cells, increased chromosome aberrations in the regenerating liver and an increase in micronuclei in red blood cells. Biochemical and microdosimetry studies showed that animals placed on the HTO regimen reached tritium equilibrium in the body water in approximately 17 to 21 days with a more gradual increase in bound tritium. When animals maintained for 180 days on 3.0 ..mu..Ci/ml HTO were placed on a tap water regimen, the tritium level in tissue dropped from the equilibrium value of 2.02 ..mu..Ci/ml before withdrawal to 0.001 ..mu..Ci/ml at 28 days. 18 references.

  13. GAMMA-RAY BURST DYNAMICS AND AFTERGLOW RADIATION FROM ADAPTIVE MESH REFINEMENT, SPECIAL RELATIVISTIC HYDRODYNAMIC SIMULATIONS

    SciTech Connect

    De Colle, Fabio; Ramirez-Ruiz, Enrico [Astronomy and Astrophysics Department, University of California, Santa Cruz, CA 95064 (United States); Granot, Jonathan [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Lopez-Camara, Diego, E-mail: fabio@ucolick.org [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ap. 70-543, 04510 D.F. (Mexico)

    2012-02-20

    We report on the development of Mezcal-SRHD, a new adaptive mesh refinement, special relativistic hydrodynamics (SRHD) code, developed with the aim of studying the highly relativistic flows in gamma-ray burst sources. The SRHD equations are solved using finite-volume conservative solvers, with second-order interpolation in space and time. The correct implementation of the algorithms is verified by one-dimensional (1D) and multi-dimensional tests. The code is then applied to study the propagation of 1D spherical impulsive blast waves expanding in a stratified medium with {rho}{proportional_to}r{sup -k}, bridging between the relativistic and Newtonian phases (which are described by the Blandford-McKee and Sedov-Taylor self-similar solutions, respectively), as well as to a two-dimensional (2D) cylindrically symmetric impulsive jet propagating in a constant density medium. It is shown that the deceleration to nonrelativistic speeds in one dimension occurs on scales significantly larger than the Sedov length. This transition is further delayed with respect to the Sedov length as the degree of stratification of the ambient medium is increased. This result, together with the scaling of position, Lorentz factor, and the shock velocity as a function of time and shock radius, is explained here using a simple analytical model based on energy conservation. The method used for calculating the afterglow radiation by post-processing the results of the simulations is described in detail. The light curves computed using the results of 1D numerical simulations during the relativistic stage correctly reproduce those calculated assuming the self-similar Blandford-McKee solution for the evolution of the flow. The jet dynamics from our 2D simulations and the resulting afterglow light curves, including the jet break, are in good agreement with those presented in previous works. Finally, we show how the details of the dynamics critically depend on properly resolving the structure of the relativistic flow.

  14. Spirosoma montaniterrae sp. nov., an ultraviolet and gamma radiation-resistant bacterium isolated from mountain soil.

    PubMed

    Lee, Jae-Jin; Kang, Myung-Suk; Joo, Eun Sun; Kim, Myung Kyum; Im, Wan-Taek; Jung, Hee-Young; Srinivasan, Sathiyaraj

    2015-07-01

    A Gram-negative, yellow-pigmented, long-rod shaped bacterial strain designated DY10(T) was isolated from a soil sample collected at Mt. Deogyusan, Jeonbuk province, South Korea. Optimum growth observed at 30°C and pH 7. No growth was observed above 1% (w/v) NaCl. Comparative 16S rRNA gene sequence analysis showed that strain DY10(T) belonged to the genus Spirosoma and was distantly related to Spirosoma arcticum R2-35(T) (91.0%), Spirosoma lingual DSM 74(T) (90.8%), Spirosoma endophyticum EX36(T) (90.7%), Spirosoma panaciterrae DSM 21099(T) (90.5%), Spirosoma rigui WPCB118(T) (90.2%), Spirosoma spitsbergense DSM 19989(T) (89.8%), Spirosoma luteum DSM 19990(T) (89.6%), Spirosoma oryzae RHs22(T) (89.6%), and Spirosoma radiotolerans DG5A(T) (89.1%). Strain DY10(T) showed resistance to gamma and ultraviolet radiation. The chemotaxonomic characteristics of strain DY10(T) were consistent with those of the genus Spirosoma, with the quinone system with MK-7 as the predominant menaquinone, iso-C15:0, C16:1 ?5c, and summed feature3 (C16:1 ?7c/C16:1 ?6c), and phosphatidylethanolamine as the major polar lipid. The G+C content of the genomic DNA was 53.0 mol%. Differential phenotypic properties with the closely related type strains clearly distinguished strain DY10(T) from previously described members of the genus Spirosoma and represents a novel species in this genus, for which the name Spirosoma montaniterrae sp. nov. is proposed. The type strain is DY10(T) (=KCTC 23999(T) =KEMB 9004-162(T) =JCM 18492(T)). PMID:26115990

  15. Solid low-level radioactive waste radiation stability studies 

    E-print Network

    Williams, Arnold Andre?

    1989-01-01

    of Advisory Committee: Dr. Milton E. McLain A series of experiments were performed in which ion-exchange resins were subjected to extreme radiation doses, in order to determine gas pressures that might arise from combustible radiolytic gas concentrations... in radwaste containers (specifically high density polyethylene (HDPE) ? high integrity containers (HIC's)). The experiments were performed by using several sample weights (2, 4, and 8 grams of resins) for four categories. The categories consisted of (I) new...

  16. Complete genome sequence of Spirosoma radiotolerans, a gamma-radiation-resistant bacterium isolated from rice field in South Korea.

    PubMed

    Kim, Myung Kyum; Back, Chang-Gi; Jung, Hee-Young; Srinivasan, Sathiyaraj

    2015-08-20

    Spirosoma radiotolerans is a Gram-negative, short rod-shaped and gamma-radiation-resistant bacterium isolated from rice field in South Korea (GPS; 37°34'30?N, 127°00'30?E). The complete genome of S. radiotolerans consists of a chromosome (7,029,352bp). From the genome sequence database, we have identified the cluster of genes responsible for DNA recovery from ionizing radiation. The key enzymes for the nucleotide excision repair (NER) were investigated and were identified, suggesting that S. radiotolerans DG5A use (NER) pathways for efficient removal of pyrimidine dimers which are the most abundant type of UV-induced damage. Complete genome information enables further studies on the DNA repair mechanisms during the ionizing radiation. PMID:26008623

  17. Enhanced radiation-induced cell killing and prolongation of gammaH2AX foci expression by the histone deacetylase inhibitor MS-275.

    PubMed

    Camphausen, Kevin; Burgan, William; Cerra, Michael; Oswald, Kelli A; Trepel, Jane B; Lee, Min-Jung; Tofilon, Philip J

    2004-01-01

    Histone deacetylase (HDAC) inhibitors are undergoing clinical evaluation for cancer therapy. Because HDAC modulates chromatin structure and gene expression, parameters considered to influence radioresponse, we have investigated the effects of the HDAC inhibitor MS-275 on the radiosensitivity of two human tumor cell lines (DU145 prostate carcinoma and U251 glioma). Acetylation status of histones H3 and H4 was determined as a function of time after MS-275 addition to and removal from culture medium. Histone acetylation increased by 6 h after MS-275 addition, reaching a maximum between 24 and 48 h of exposure; providing fresh drug-free medium then resulted in a decrease in histone acetylation that began by 6 h and approached untreated levels by 16 h. Treatment of cells with MS-275 for 48 h followed by irradiation had little or no effect on radiation-induced cell death. However, exposure to MS-275 before and after irradiation resulted in an increase in radiosensitivity with dose enhancement factors of 1.9 and 1.3 for DU145 and U251 cells, respectively. This MS-275 treatment protocol did not result in a redistribution of the cells into a more radiosensitive phase of the cell cycle or in an increase in apoptosis. However, MS-275 did modify the time course of gammaH2AX expression in irradiated cells. Whereas there was no significant difference in radiation-induced gammaH2AX foci at 6 h, the number of cells expressing gammaH2AX foci was significantly greater in the MS-275-treated cells at 24 h after irradiation. These results indicate that MS-275 can enhance radiosensitivity and suggest that this effect may involve an inhibition of DNA repair. PMID:14729640

  18. Transport and noise properties of Si nanowire channels with different lengths before and after gamma radiation treatment

    SciTech Connect

    Li, Jing; Vitusevich, Svetlana; Pud, Sergii; Sydoruk, Viktor; Offenhäusser, Andreas [Peter Grünberg Institute, Forschungszentrum Jülich (Germany); Petrychuk, Mykhailo [Taras Shevchenko National University, Kiev (Ukraine); Danilchenko, Boris [Institute of Physics, NASU, Kiev (Ukraine)

    2013-12-04

    The transport properties of Si nanowire (NW) structures fabricated on the basis of silicon on insulator (SOI) wafers were studied using noise spectroscopy before and after treatment with small doses of gamma radiation. The total resistance obtained from the I-V characteristics of Si NW structures scaled perfectly with length. Normalized flicker noise demonstrated 1/L{sup 2} dependence, which is a characteristic of dominant noise contribution from near-contact regions. The behavior changed to 1/L dependence after a small dose (1×10{sup 4} Gy) of gamma radiation treatment. Comparison of the random telegraph signal (RTS) noise parameters in the samples with small lengths before and after the treatment revealed a decrease in RTS amplitude and a shift to a lower frequency range after gamma irradiation. These results confirmed that the main changes in the samples were related to strain relaxation near-contact regions. In addition, such treatment resulted in a considerable decrease in the scattering data of device parameters.

  19. Results of calculations of external gamma radiation exposure rates from fallout and the related radionuclide compositions. Operation Plumbob, 1957

    SciTech Connect

    Hicks, H.G.

    1981-07-01

    Data are presented on calculated gamma radiation exposure rates and rates and ground deposition of related radionuclides resulting from Events that deposited detectable radioactivity outside the Nevada Test Site complex. The Events which deposited detectable radioactivity outside the Nevada Test Site complex are listed. Results of the calculations are given in the Appendices. The output of the calculation has 30 decay times. For each of these times and for zero time there are values of the external gamma radiation exposure rate normalized to 1 mR/h, 1 m above the surface, 12 h after the event. The /sup 233/U, /sup 235/U and /sup 239/ /sup 240/Pu data were omitted primarily to keep the output unclassified. Surface roughness effects are simulated by using Beck's values. According to Beck, the concentration of fallout varies exponentially with soil depth. Fractionation effects were simulated by the removal of a fraction of the refractory nuclides from the calculation. In general, air drops were assumed to be unfractionated, surface and cratering Events were assumed to have 0.4 of the refractory elements present, and all other Events were assumed to have 0.5 of the refractory elements present. Each Appendix contains calculated results relating to one Event. Page 2 of each set gives the external gamma-ray exposure rates and associated values of total microcuries per square meter at 30 decay intervals and at zero time. Calculated values for each radionuclide at various decay intervals are given in the remaining pages. (ERB)

  20. Effects of gamma irradiation on the radiation-resistant bacteria and polyphenol oxidase activity in fresh kale juice

    NASA Astrophysics Data System (ADS)

    Kim, Dongho; Song, Hyunpa; Lim, Sangyong; Yun, Hyejeong; Chung, Jinwoo

    2007-07-01

    Gamma radiation was performed to prolong the shelf life of natural kale juice. The total aerobic bacteria in fresh kale juice, prepared by a general kitchen process, was detected in the range of 10 6 cfu/ml, and about 10 2 cfu/ml of the bacteria survived in the juice in spite of gamma irradiation treatment with a dose of 5 kGy. Two typical radiation-resistant bacteria, Bacillus megaterium and Exiguobacterium acetylicum were isolated and identified from the 5 kGy-irradiated kale juices. The D10 values of the vegetative cell and endospore of the B. megaterium in peptone water were 0.63±0.05 and 1.52±0.05 kGy, respectively. The D10 value of the E. acetylicum was calculated as 0.65±0.06 kGy. In the inoculation test, the growth of the surviving B. megaterium and E. acetylicum in the 3-5 kGy-irradiated kale juice retarded and/or decreased significantly during a 3 d post-irradiation storage period. However, there were no significant differences in the residual polyphenol oxidase activity and browning index between the nonirradiated control and the gamma irradiated kale juice during a post-irradiation period.

  1. Afterglow emission in gamma-ray bursts - I. Pair-enriched ambient medium and radiative blast waves

    NASA Astrophysics Data System (ADS)

    Nava, L.; Sironi, L.; Ghisellini, G.; Celotti, A.; Ghirlanda, G.

    2013-08-01

    Forward shocks caused by the interaction between a relativistic blast wave and the circumburst medium are thought to be responsible for the afterglow emission in gamma-ray bursts (GRBs). We consider the hydrodynamics of a spherical relativistic blast wave expanding into the surrounding medium and we generalize the standard theory in order to account for several effects that are generally ignored. In particular, we consider the role of adiabatic and radiative losses in the hydrodynamical evolution of the shock, under the assumption that the cooling losses are fast. Our model can describe adiabatic, fully radiative and semiradiative blast waves, and can describe the effects of a time-varying radiative efficiency. The equations we present are valid for arbitrary density profiles, and also for a circumburst medium enriched with electron-positron pairs. The presence of pairs enhances the fraction of shock energy gained by the leptons, thus increasing the importance of radiative losses. Our model allows us to study whether the high-energy (>0.1 GeV) emission in GRBs may originate from afterglow radiation. In particular, it is suitable to test whether the fast decay of the high-energy light curve observed in several Fermi Large Area Telescope GRBs can be ascribed to an initial radiative phase, followed by the standard adiabatic evolution.

  2. Chromosomal instability in unirradiated hemopoietic cells resulting from a delayed in vivo bystander effect of gamma radiation.

    PubMed

    Lorimore, Sally A; McIlrath, Joanne M; Coates, Philip J; Wright, Eric G

    2005-07-01

    Untargeted effects of ionizing radiation (de novo effects in the unirradiated descendants or neighbors of irradiated cells) challenge widely held views about the mechanisms of radiation-induced DNA damage with implications for the health consequences of radiation exposures particularly in the context of the induction of malignancy. To investigate in vivo untargeted effects of sparsely ionizing (low linear energy transfer) radiation, a congenic sex-mismatch bone marrow transplantation protocol has been used to repopulate the hemopoietic system from a mixture of gamma-irradiated and nonirradiated hemopoietic stem cells such that host-, irradiated donor- and unirradiated donor-derived cells can be distinguished. Chromosomal instability in the progeny of irradiated hemopoietic stem cells accompanied by a reduction in their contribution to the repopulated hemopoietic system is consistent with a delayed genomic instability phenotype being expressed in vivo. However, chromosomal instability was also shown in the progeny of the nonirradiated hemopoietic stem cells implicating a bystander mechanism. Studies of the influence of irradiated recipient stromal microenvironment and experiments replacing irradiated cells with irradiated cell-conditioned medium reveal the source of the in vivo bystander effect to be the descendants of irradiated cells, rather than irradiated cell themselves. Thus, it is possible that a radiation-induced genomic instability phenotype in vivo need not necessarily be a reflection of intrinsically unstable cells but the responses to ongoing production of inflammatory-type damaging signals as a long-term unexpected consequence of the initial single radiation exposure. PMID:15994940

  3. Protective Role of Hsp27 Protein Against Gamma Radiation-Induced Apoptosis and Radiosensitization Effects of Hsp27 Gene Silencing in Different Human Tumor Cells

    SciTech Connect

    Aloy, Marie-Therese [Universite de Lyon 1, Laboratoire de Radiobiologie Cellulaire et Moleculaire, Faculte de Medecine Lyon-Sud, Oullins (France); Hospices Civils de Lyon, Service de Radiotherapie, Centre Hospitalier Lyon-Sud, Pierre-Benite (France)], E-mail: marie-therese.aloy@sante.univ-lyon1.fr; Hadchity, Elie; Bionda, Clara [Universite de Lyon 1, Laboratoire de Radiobiologie Cellulaire et Moleculaire, Faculte de Medecine Lyon-Sud, Oullins (France); Diaz-Latoud, Chantal [Universite de Lyon 1, UMR-CNRS-5534, Centre de Genetique Moleculaire et Cellulaire, Villeurbanne (France); Claude, Line; Rousson, Robert [Universite de Lyon 1, Laboratoire de Radiobiologie Cellulaire et Moleculaire, Faculte de Medecine Lyon-Sud, Oullins (France); Arrigo, Andre-Patrick [Universite de Lyon 1, UMR-CNRS-5534, Centre de Genetique Moleculaire et Cellulaire, Villeurbanne (France); Rodriguez-Lafrasse, Claire [Universite de Lyon 1, Laboratoire de Radiobiologie Cellulaire et Moleculaire, Faculte de Medecine Lyon-Sud, Oullins (France)

    2008-02-01

    Purpose: The ability of heat shock protein 27 (Hsp27) to protect cells from stressful stimuli and its increased levels in tumors resistant to anticancer therapeutics suggest that it may represent a target for sensitization to radiotherapy. In this study, we investigate the protective role of Hsp27 against radiation-induced apoptosis and the effect of its attenuation in highly expressing radioresistant cancer cell lines. Methods and Materials: We examined clonogenic death and the kinetics of apoptotic events in different tumor cell lines overexpressing or underexpressing Hsp27 protein irradiated with photons. The radiosensitive Jurkat cell line, which does not express Hsp27 constitutively or in response to {gamma}-rays, was stably transfected with Hsp27 complementary DNA. Attenuation of Hsp27 expression was accomplished by antisense or RNAi (interfering RNA) strategies in SQ20B head-and-neck squamous carcinoma, PC3 prostate cancer, and U87 glioblastoma radioresistant cells. Results: We measured concentration-dependent protection against the cytotoxic effects of radiation in Jurkat-Hsp27 cells, which led to a 50% decrease in apoptotic cells at 48 hours in the highest expressing cells. Underlying mechanisms leading to radiation resistance involved a significant increase in glutathione levels associated with detoxification of reactive oxygen species, a delay in mitochondrial collapse, and caspase activation. Conversely, attenuation of Hsp27 in SQ20B cells, characterized by their resistance to apoptosis, sensitizes cells to irradiation. This was emphasized by increased apoptosis, decreased glutathione basal level, and clonogenic cell death. Sensitization to irradiation was confirmed in PC3 and U87 radioresistant cells. Conclusion: Hsp27 gene therapy offers a potential adjuvant to radiation-based therapy of resistant tumors.

  4. Effects of different levels of vitamin C on UV radiation-induced DNA damage

    Microsoft Academic Search

    Dianfeng Zhou; Hang Heng; Kang Ji; Weizhong Ke

    2005-01-01

    The Raman spectra of DNA in different levels of vitamin C with 10- and 30-min ultraviolet (UV) radiations were reported. The intensity of UV radiation was 18.68 W\\/m2. The experimental results proved that vitamin C could alone prevent UV radiation from damaging DNA, but the effects depended on the concentration of vitamin C. When the concentration of vitamin C was

  5. TeV gamma rays from the blazar H 1426+428 and the diffuse extragalactic background radiation

    Microsoft Academic Search

    F. Aharonian; A. Akhperjanian; J. Barrio; M. Beilicke; K. Bernlohr; H. Borst; H. Bojahr; O. Bolz; J. Contreras; R. Cornils; J. Cortina; S. Denninghoff; V. Fonseca; M. Girma; J. Gonzalez; N. Gotting; G. Heinzelmann; G. Hermann; A. Heusler; W. Hofmann; D. Horns; I. Jung; R. Kankanyan; M. Kestel; J. Kettler; A. Kohnle; A. Konopelko; H. Kornmeyer; D. Kranich; H. Krawczynski; H. Lampeitl; M. Lopez; E. Lorenz; F. Lucarelli; N. Magnussen; O. Mang; H. Meyer; R. Mirzoyan; A. Moralejo; E. Ona; L. Padilla; M. Panter; R. Plaga; A. Plyasheshnikov; G. Puhlhofer; G. Rauterberg; A. Rohring; W. Rhode; J. Robrade; G. Rowell; V. Sahakian; M. Samorski; M. Schilling; F. Schroder; I. Sevilla; M. Siems; W. Stamm; M. Tluczykont; H. J. Volk; C. A. Wiedner; W. Wittek; Alikhanian Br

    2002-01-01

    The detection of TeV gamma-rays from the blazar H 1426+428 at an integral\\u000aflux level of (4 +- 2(stat) +- 1(syst)) 10^(-12) erg cm^(-2) s^(-1) above 1 TeV\\u000awith the HEGRA imaging atmospheric Cherenkov telescope system is reported. H\\u000a1426+428 is located at a redshift of z=0.129, which makes it the most distant\\u000asource detected in TeV gamma-rays so far.

  6. Electrochemical reactions of some organic free radicals at colloidal silver in aqueous solution. [Gamma radiation

    SciTech Connect

    Henglein, A.

    1980-12-11

    Electron-transfer processes between simple 1-hydroxyalkyl, 1-ethoxyethyl, and 2-hydroxycyclohexadienyl radicals and metal ions at the surface of colloidal silver are described. C/sub 6/H/sub 6/OH radicals are oxidized by Ag/sup +/ to yield phenol. In the absence of Ag/sup +/, no electron exchange between C/sub 6/H/sub 6/OH and the silver particles takes place. When the silver particles carry a tiny deposit of thallium metal, the C/sub 6/H/sub 6/OH radicals are reduced. Cu/sup +/ (and Cu/sup 2 +/) ions adsorbed on the silver particles oxidize C/sub 6/H/sub 6/OH radicals. However, reduction of C/sub 6/H/sub 6/OH by Cu/sup +/ occurs, if the silver particles are covered with copper metal. 1-Hydroxyalkyl and 2-ethoxyethyl radicals reduce Tl/sup +/ ions in the presence of colloidal silver, but oxidize Tl atoms in homogeneous solution. Water can be decomposed to yield H/sub 2/ by 1-hydroxy-1-methyl and 1-hydroxyethyl, but not by 1-hydroxymethyl, 1-ethoxyethyl, and 2-hydroxycyclohexadienyl radicals. These findings are discussed in terms of standard potentials for the oxidation and reduction of the radicals and in terms of distributions of occupied and unoccupied electronic redox levels in the radicals and the colloidal metal. In these experiments ..gamma.. radiolysis was used to produce the radicals at a controlled rate.

  7. Mtf-1 lymphoma-susceptibility locus affects retention of large thymocytes with high ROS levels in mice after {gamma}-irradiation

    SciTech Connect

    Maruyama, Masaki [Department of Molecular Genetics, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi 1-757, Niigata 951-8510 (Japan); Third Department of Internal Medicine, Niigata University School of Medicine, Asahimachi 1-757, Niigata 951-8510 (Japan); Yamamoto, Takashi [Department of Molecular Genetics, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi 1-757, Niigata 951-8510 (Japan); Kohara, Yuki [Department of Molecular Genetics, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi 1-757, Niigata 951-8510 (Japan); Katsuragi, Yoshinori [Department of Molecular Genetics, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi 1-757, Niigata 951-8510 (Japan); Mishima, Yukio [Department of Molecular Genetics, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi 1-757, Niigata 951-8510 (Japan); Transdisciplinary Research, Niigata University, Asahimachi 1-757, Niigata 951-8510 (Japan); Aoyagi, Yutaka [Third Department of Internal Medicine, Niigata University School of Medicine, Asahimachi 1-757, Niigata 951-8510 (Japan); Kominami, Ryo [Department of Molecular Genetics, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi 1-757, Niigata 951-8510 (Japan); Transdisciplinary Research, Niigata University, Asahimachi 1-757, Niigata 951-8510 (Japan); E-mail: rykomina@med.niigata-u.ac.jp

    2007-03-02

    Mouse strains exhibit different susceptibilities to {gamma}-ray-induced thymic lymphomas. Our previous study identified Mtf-1 (metal responsive transcription factor-1) as a candidate susceptibility gene, which is involved in the radiation-induced signaling pathway that regulates the cellular reactive oxygen species (ROS). To reveal the mechanism for the increased susceptibility conferred by Mtf-1 locus, we examined early effects of {gamma}-ray on ROS levels in vivo and its difference between Mtf-1 susceptible and resistant congenic mice. Here, we show the detection of clonally growing thymocytes at 4 weeks after irradiation, indicating the start of clonal expansion at a very early stage. We also show that large thymocytes with higher ROS levels and a proliferation capacity were more numerous in the Mtf-1 susceptible mice than the resistant mice when examined at 7 days after irradiation, although such tendency was not found in mice lacking one allele of Bcl11b tumor suppressor gene. This high retention of the large thymocytes, at a high risk for ROS-induced mutation, is a compensatory proliferation and regeneration response to depletion of the thymocytes after irradiation and the response is likely to augment the development of prelymphoma cells leading to thymic lymphomas.

  8. Jupiter radiation test levels and their expected impact on an encounter mission

    NASA Technical Reports Server (NTRS)

    Barengoltz, J. B.

    1972-01-01

    The upper limit, of electron and proton fluences for a thermoelectric outer planet spacecraft mission in a near-Jupiter environment, for use as radiation design restraints, were extracted from a model of the Jovian trapped radiation belts. Considerations of radiation effects in semiconductor devices were employed to construct simplified radiation test levels based on the design restraints. Corresponding levels, based on the nominal belt models, are one to three orders of magnitude smaller. In terms of expected radiation-induced degradation in semiconductor devices, an encounter with an environment as severe as the design restraints would require hardening the system in order to guarantee high reliability. On the other hand, the nominal levels would only necessitate care in the selection of components and the avoidance of certain semiconductor components.

  9. Determination of gamma radioactivity levels and associated dose rates of soil samples of the Akkuyu/Mersin using high-resolution gamma-ray spectrometry.

    PubMed

    Ozmen, S F; Boztosun, I; Yavuz, M; Tunç, M R

    2014-03-01

    In this study several soil samples were collected from the Büyükeceli district where Turkey's first nuclear power plant will be built and radioactivity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs were determined by gamma spectrometry using a high-purity germanium detector. The measured activity concentrations in soil samples ranged from 9.8 ± 0.7 to 258.6 ± 15.8, 11.7 ± 0.9 to 85.6 ± 5.0, 173.8 ± 2.1 to 1949.5 ± 14.7 and 0.4 ± 0.1 to 72.2 ± 2.2 Bq kg(-1) for (226)Ra, (232)Th, (40)K and (137)Cs, respectively. Findings are in good agreement with the published results of neighbouring areas. The absorbed gamma dose rate (D) in air and the annual effective dose of soil samples were calculated to be 80.2 nGy h(-1) and 98.3 mSv y(-1), respectively. The results show that the radiation hazard in the Büyükeceli district is insignificant. The data presented in this study would be very useful to determine the future effects of the nuclear power plant to the environment. PMID:24214909

  10. Linking Gamma-H2AX Foci and Cancer in Rat Skin Exposed to Heavy Ions and Electron Radiation

    PubMed Central

    Burns, Fredric J.; Tang, Moon-shong; Wu, Feng; Schmid, Ernst

    2015-01-01

    Abstract This study uses acute doses of three test radiations, [40Ar ions (L = 125 keV??1), 20Ne ions (L = 25 keV??1) and electron radiation] to examine a potential quantitative link between rat skin cancer induction and gamma-H2AX foci in rat keratinocytes exposed in vitro to radiations with comparable L values. Theory provided a testable link between cancer yield and gamma-H2AX foci yields: YCa(D,L)rat?1 = (NF)2?1YAX(D,L)keratinocyte?1 (eqn 1), where YCa(D,L) is cancers(rat) ?1 at 1.0 y, YAX(D,L) is in vitro gamma-H2AX foci(keratinocyte) ?1, D is radiation dose, L is linear energy transfer, N is irradiated keratinocytes in vivo, and F is the error rate of end joining. An explicit expression for cancer yield was derived based on cancers arising in the ion track region in proportion to D and L (first term) and independently in proportion to D2 in the delta ray region in between the ion tracks (second term): YCa(D,L) = CCaLD + BCaD2 (eqn 1a). Parameters quantified include: CCa = 0.000589 ± 0.000150 cancers-micron[rat(kev)Gy]?1; BCa = 0.0088 ± 0.0035 cancers(ratGy2)?1, F = (8.18 ± 0.91) × 10?10; N = (8.8 ± 1.2) × 107 and (NF)2?1 = 0.036 ± 0.006 cancer keratinocyte(rat H2AX foci)?1. Verification of eqns (1) and (1a) and the constancy of F support the hypothesis that end-rejoining errors play a major role in radiation carcinogenesis in rat skin. Cancer yields per rat were consistently predictable based on gamma-H2AX foci yields in keratinocytes in vitro such that 27.8 H2AXfoci(keratinocyte)?1 predicted 1.0 cancer(rat)?1 at 1 y. PMID:26107436

  11. Radiation reaction at the level of the action

    NASA Astrophysics Data System (ADS)

    Birnholtz, Ofek; Hadar, Shahar; Kol, Barak

    2014-09-01

    The aim of this paper is to highlight a recently proposed method for the treatment of classical radiative effects, in particular radiation reaction, via effective field theory methods. We emphasize important features of the method and in particular the doubling of fields. We apply the method to two simple systems: a mass-rope system and an electromagnetic charge-field system. For the mass-rope system in 1 + 1 dimensions we derive a double-field effective action for the mass which describes a damped harmonic oscillator. For the EM charge-field system, i.e. the system of an accelerating electric charge in 3 + 1 dimensions, we show a reduction to a 1 + 1 dimensions radial system of an electric dipole source coupled to an electric dipole field (analogous to the mass coupled to the rope). For this system we derive a double-field effective action and reproduce in an analogous way the leading part of the Abraham-Lorentz-Dirac force.

  12. Radiation Metabolomics. 2. Dose- and Time-Dependent Urinary Excretion of Deaminated Purines and Pyrimidines after Sublethal Gamma-Radiation Exposure in Mice

    PubMed Central

    Tyburski, John B.; Patterson, Andrew D.; Krausz, Kristopher W.; Slavík, Josef; Fornace, Albert J.; Gonzalez, Frank J.; Idle, Jeffrey R.

    2009-01-01

    Gamma-radiation exposure of humans is a major public health concern as the threat of terrorism and potential hostile use of radiological devices increases worldwide. We report here the effects of sublethal ?-radiation exposure on the mouse urinary metabolome determined using ultra-performance liquid chromatography-coupled time-of-flight mass spectrometry-based metabolomics. Five urinary biomarkers of sublethal radiation exposure that were statistically significantly elevated during the first 24 h after exposure to doses ranging from 1 to 3 Gy were unequivocally identified by tandem mass spectrometry. These are deaminated purine and pyrimidine derivatives, namely, thymidine, 2?-deoxyuridine, 2?-deoxyxanthosine, xanthine and xanthosine. Furthermore, the aminopyrimidine 2?-deoxycytidine appeared to display reduced urinary excretion at 2 and 3 Gy. The elevated biomarkers displayed a time-dependent excretion, peaking in urine at 8–12 h but returning to baseline by 36 h after exposure. It is proposed that 2?-deoxyuridine and 2?-deoxyxanthosine arise as a result of ? irradiation by nitrosative deamination of 2?-deoxycytidine and 2?-deoxyguanosine, respectively, and that this further leads to increased synthesis of thymidine, xanthine and xanthosine. The urinary excretion of deaminated purines and pyrimidines, at the expense of aminopurines and aminopyrimidines, appears to form the core of the urinary radiation metabolomic signature of mice exposed to sublethal doses of ionizing radiation. PMID:19580506

  13. Chemical protection against mixed gamma-neutron radiation with various contributions of neutrons to the absorbed dose

    NASA Technical Reports Server (NTRS)

    Vasin, M. V.; Kozlov, V. A.; Razgovorov, B. L.; Krasnykh, I. G.

    1973-01-01

    Results are presented of studies on antiradiation effectiveness of cystamine, AET, tsistafos and 5-MOT in intraperitoneal administration to mice under conditions of mixed gamma-neutron irradiation with a neutron contribution to the absorbed dose of approximately 35 or 90%. Under conditions of mixed gamma-neutron irradiation with a neutron contribution to the absorbed dose of about 90%, AET and tsistafos slightly decreased the severity of radiation damage. The survival rate of the mice under these conditions was 24.2 (AET) and 26.8% (tsistafos) at LD90/30. Cystamine and 5-MOT were ineffective. In joint use of AET and tsistafos with 5-MOT, the protective properties of the aminothiols did not increase. With a drop in the contribution of the neutron component to 35%, AET, cystamine and tsistafos produced remarkable antiradiation effects, while 5-MOT did not.

  14. Quantum electrodynamic calculation of quantum beats in a spontaneously radiating three level system

    Microsoft Academic Search

    A. Schenzle; Richard G. Brewer

    1975-01-01

    The coherence properties of a spontaneously radiating three-level atomic system are investigated in a first principle calculation that utilizes either coherent or incoherent preparation. Quantum beat phenomena are explained for the first time in a manner that reveals the statistical nature of the preparative step as well as a possible radiative correction to the beat frequency.

  15. Secret fallout. Low-level radiation from Hiroshima to Three Mile Island

    Microsoft Academic Search

    Sternglass

    1981-01-01

    The author, Professor of radiation physics at the University of Pittsburgh, presents evidence for the cumulative effects of low-level radiation on health. In the early 1960s, when nuclear testing created fallout radioactivity, Dr. Sternglass states that he discovered a related increase in fetal deaths, infant mortality, and certain kinds of cancer. Nuclear power plants became the topic of his studies

  16. Projection of needs for gamma radiation sources and other radioisotopes and assessment of alternatives for providing radiation sources

    SciTech Connect

    Ross, W.A.; Jensen, G.A.; Clark, L.L.; Eakin, D.E.; Jarrett, J.H.; Katayama, Y.B.; McKee, R.W.; Morgan, L.G.; Nealey, S.M.; Platt, A.M.; Tingey, G.L.

    1989-06-01

    Pacific Northwest Laboratory reviewed the projected uses and demands for a variety of nuclear byproducts. Because the major large-scale near-term demand is for gamma irradiation sources, this report concentrates on the needs for gamma sources and evaluates the options for providing the needed material. Projections of possible growth in the irradiation treatment industry indicate that there will be a need for 180 to 320 MCi of /sup 60/Co (including /sup 137/Cs equivalent) in service in the year 2000. The largest current and projected use of gamma irradiation is for the sterilization of medical devices and disposable medical supplies. Currently, 40% of US disposable medical products are treated by irradiation, and within 10 years it is expected that 90% will be treated in this manner. Irradiation treatment of food for destruction of pathogens or parasites, disinfestation, or extension of allowable storage periods is estimated to require an active inventory of 75 MCi of /sup 60/Co-equivalent gamma source in about a decade. 90 refs., 7 figs., 25 tabs.

  17. Combination of PTEN and {gamma}-Ionizing Radiation Enhances Cell Death and G{sub 2}/M Arrest Through Regulation of AKT Activity and p21 Induction in Non-Small-Cell Lung Cancer Cells

    SciTech Connect

    Park, Jong Kuk; Jung, Hae-Yun; Park, Seon Ho; Kang, Seung Yi; Yi, Mi-Rang; Um, Hong Duck [Laboratory of Radiation Tumor Physiology, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Hong, Sung Hee [Laboratory of Radiation Tumor Physiology, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)], E-mail: gobrian@kcch.re.kr

    2008-04-01

    Purpose: To identify the role of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) during {gamma}-ionizing radiation ({gamma}-IR) treatment for non-small-cell lung cancer cells. Methods and Materials: Wild-type PTEN or mutant forms of PTEN plasmids were transfected to construct stable transfectants of the NCI-H1299 non-small-cell lung cancer cell line. Combined effects of PTEN expression and IR treatment were tested using immunoblot, clonogenic, and cell-counting assays. Related signaling pathways were studied with immunoblot and kinase assays. Results: At steady state, stable transfectants showed almost the same proliferation rate but had different AKT phosphorylation patterns. When treated with {gamma}-IR, wild-type PTEN transfectants showed higher levels of cell death compared with mock vector or mutant transfectants, and showed increased G{sub 2}/M cell-cycle arrest accompanied by p21 induction and CDK1 inactivation. NCI-H1299 cells were treated with phosphosinositide-3 kinase (PI3K)/AKT pathway inhibitor (LY29002), resulting in reduced AKT phosphorylation levels. Treatment of NCI-H1299 cells with LY29002 and {gamma}-IR resulted in increased cell-cycle arrest and p21 induction. Endogenous wild-type PTEN-containing NCI-H460 cells were treated with PTEN-specific siRNA and then irradiated with {gamma}-IR: however reduced PTEN levels did not induce cell-cycle arrest or p21 expression. Conclusions: Taken together, these findings indicate that PTEN may modulate cell death or the cell cycle via AKT inactivation by PTEN and {gamma}-IR treatment. We also propose that a PTEN-PI3K/AKT-p21-CDK1 pathway could regulate cell death and the cell cycle by {gamma}-IR treatment.

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

    Microsoft Academic Search

    Karolin Kamel Abdul-Aziz; M. J. Tuorkey

    2010-01-01

    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

  19. Effects of gamma radiation on nymphal development and reproductive capacity of the large milkweed bug, Oncopeltus fasciatus (Dallas) (Hemiptera - Lygaeidae)

    SciTech Connect

    Moursy, L.E.

    1985-01-01

    Gamma radiation adversely affected important fitness components of Oncopeltus fasciatus, particularly as expressed by nymphal development, subsequent reproductive capacity, mating competitiveness and longevity. Early treated 5th instar nymphs are about 2X more sensitive to gamma radiation than late treated 5th instar nymphs based upon LD50 values. The extremes in sensitivity were 5.01 kilorads (krad) for early treated males and 13.09 krad for females treated late in the 5th instar. Wing deformities resulted from doses in the same range as those for mortality. Fifty percent of early treated males had wing deformities at a dose of 10.81 krad while a dose of 12.5 and 12.89 krad was necessary for 50% wing deformities in males and females, respectively, when treated late in the 5th instar. Fecundity and fertility were affected at lower dosages of radiation than for mortality. The treatment of both sexes produced the greatest effect. Fecundity was reduced by 50% at 1.22 krad, while 50% reduction in fertility occurred at about half that dose, or 0.66 krad. Somewhat greater doses were required when females alone were treated and mated with untreated males. In this case a 50% reduction occurred with 1.87 and 1.07 krad for fecundity and fertility, respectively. When males alone were treated, ED50 values were 2.24 and 1.58 krad for fecundity and fertility, respectively.

  20. Enrichment of magnetic alignment stimulated by {gamma}-radiation in core-shell type nanoparticle Mn-Zn ferrite

    SciTech Connect

    Naik, P. P.; Tangsali, R. B. [Department of Physics, Goa University, Taleigao Plateau, Goa-403206 (India); Sonaye, B.; Sugur, S. [Goa Medical College, Bambolim, Goa (India)

    2013-02-05

    Core shell type nanoparticle Mn{sub x}Zn{sub 1-x}Fe{sub 2}O{sub 4} systems with x=0.55, 0.65 and 0.75 were prepared using autocombustion method. The systems were characterized using tools like XRD and IR for structure confirmation. Magnetic parameter measurements like Saturation magnetization and coercivity were obtained from hysteresis loop which exhibited a symmetry shift due to core shell nature of the nanoparticles. Nanoparticles of particle size between 21.2nm to 25.7nm were found to show 20 percent shrinkage after being radiated by the {gamma}-radiation. This is due to variation in the cation distribution which also affects the cell volume of the cubic cell. Lattice constant reduction observed is reflected in the magnetic properties of the samples. A considerable hike in the saturation magnetization of the samples was observed due to enrichment of magnetic alignment in the magnetic core of the particles. Samples under investigation were irradiated with gamma radiation from Co{sup 60} source for different time intervals.

  1. The ST environment: Expected charged particle radiation levels

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.

    1978-01-01

    The external (surface incident) charged particle radiation, predicted for the ST satellite at the three different mission altitudes, was determined in two ways: (1) by orbital flux-integration and (2) by geographical instantaneous flux-mapping. The latest standard models of the environment were used in this effort. Magnetic field definitions for three nominal circular trajectories and for the geographic mapping positions were obtained from a current field model. Spatial and temporal variations or conditions affecting the static environment models were considered and accounted for, wherever possible. Limited shielding and dose evaluations were performed for a simple geometry. Results, given in tabular and graphical form, are analyzed, explained, and discussed. Conclusions are included.

  2. Near-Core and In-Core Neutron Radiation Monitors for Real Time Neutron Flux Monitoring and Reactor Power Level Measurements

    SciTech Connect

    Douglas S. McGregor; Marvin L. Adams; Igor Carron; Paul Nelson

    2006-06-12

    MPFDs are a new class of detectors that utilize properties from existing radiation detector designs. A majority of these characteristics come from fission chamber designs. These include radiation hardness, gamma-ray background insensitivity, and large signal output.

  3. First Study of the Radiation-Amplitude Zero in W{gamma} Production and Limits on Anomalous WW{gamma} Couplings at {radical}(s)=1.96 TeV

    SciTech Connect

    Abazov, V. M.; Alexeev, G. D.; Kalinin, A. M.; Kharzheev, Y. M.; Malyshev, V. L.; Tokmenin, V. V.; Vertogradov, L. S.; Yatsunenko, Y. A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Abbott, B.; Gutierrez, P.; Hossain, S.; Jain, S.; Rominsky, M.; Severini, H.; Skubic, P.; Strauss, M. [University of Oklahoma, Norman, Oklahoma 73019 (United States); Abolins, M.; Benitez, J. A.; Brock, R.; Dyer, J. [Michigan State University, East Lansing, Michigan 48824 (United States)] (and others)

    2008-06-20

    We present results from a study of pp{yields}W{gamma}+X events utilizing data corresponding to 0.7 fb{sup -1} of integrated luminosity at {radical}(s)=1.96 TeV collected by the D0 detector at the Fermilab Tevatron Collider. We set limits on anomalous WW{gamma} couplings at the 95% C.L. The one-dimensional 95% C.L. limits are 0.49<{kappa}{sub {gamma}}<1.51 and -0.12<{lambda}{sub {gamma}}<0.13. We make the first study of the charge-signed rapidity difference between the lepton and the photon and find it to be indicative of the standard model radiation-amplitude zero in the W{gamma} system.

  4. Properties of P30 Levels from the Reaction Si29(p, gamma)P30. II

    Microsoft Academic Search

    Gale I. Harris; A. K. Hyder; J. Walinga

    1969-01-01

    A previous investigation of the gamma-ray decay schemes of 7 resonances in the reaction Si29(p, gamma)P30 in the range Ep=700-1750 keV has been extended to 24 resonances in the range Ep=300-1800 keV. The new decay scheme studies were conducted with a 40-cc Ge(Li) detector. The spins, parities, isobaric spins, lifetimes, and transition multipolarity mixings for many resonances and bound states

  5. Absorption of Nuclear Gamma-rays on the Starlight Radiation in FR I Sources: the Case of Centaurus A

    E-print Network

    L. Stawarz; F. Aharonian; S. Wagner; M. Ostrowski

    2006-07-17

    Several BL Lac objects are confirmed sources of variable and strongly Doppler-boosted TeV emission produced in the nuclear portions of their relativistic jets. It is more than probable, that also many of the FR I radio galaxies, believed to be the parent population of BL Lacs, are TeV sources, for which Doppler-hidden nuclear gamma-ray radiation may be only too weak to be directly observed. Here we show, however, that about one percent of the total time-averaged TeV radiation produced by the active nuclei of low-power FR I radio sources is inevitably absorbed and re-processed by photon-photon annihilation on the starlight photon field, and the following emission of the created and quickly isotropized electron-positron pairs. In the case of the radio galaxy Centaurus A, we found that the discussed mechanism can give a distinctive observable feature in the form of an isotropic gamma-ray halo. It results from the electron-positron pairs injected to the interstellar medium of the inner parts of the elliptical host by the absorption process, and upscattering starlight radiation via the inverse-Compton process mainly to the GeV-TeV photon energy range. Such a galactic gamma-ray halo is expected to possess a characteristic spectrum peaking at ~0.1 TeV photon energies, and the photon flux strong enough to be detected by modern Cherenkov Telescopes and, in the future, by GLAST. These findings should apply as well to the other nearby FR I sources.

  6. Sunlight-Exposed Biofilm Microbial Communities Are Naturally Resistant to Chernobyl Ionizing-Radiation Levels

    Microsoft Academic Search

    Marie Ragon; Gwendal Restoux; David Moreira; Anders Pape Møller; Purificación López-García

    2011-01-01

    BackgroundThe Chernobyl accident represents a long-term experiment on the effects of exposure to ionizing radiation at the ecosystem level. Though studies of these effects on plants and animals are abundant, the study of how Chernobyl radiation levels affect prokaryotic and eukaryotic microbial communities is practically non-existent, except for a few reports on human pathogens or soil microorganisms. Environments enduring extreme

  7. Infrared radiation and inversion population of CO2 laser levels in Venusian and Martian atmospheres

    NASA Technical Reports Server (NTRS)

    Gordiyets, B. F.; Panchenko, V. Y.

    1983-01-01

    Formation mechanisms of nonequilibrium 10 micron CO2 molecule radiation and the possible existence of a natural laser effect in the upper atmospheres of Venus and Mars are theoretically studied. An analysis is made of the excitation process of CO2 molecule vibrational-band levels (with natural isotropic content) induced by direct solar radiation in bands 10.6, 9.4, 4.3, 2.7 and 2.0 microns. The model of partial vibrational-band temperatures was used in the case. The problem of IR radiation transfer in vibrational-rotational bands was solved in the radiation escape approximation.

  8. A simulation study investigating a radiation detector utilizing the prompt gamma range verification technique for proton radiotherapy

    NASA Astrophysics Data System (ADS)

    Lau, Andrew David

    Proton therapy has shown to be a viable therapy for radiation oncology applications. The advantages of using protons as compared to photons in the treatments of diseases with radiation are numerous including the ability to deliver overall lower amounts of lethal radiation doses to the patient. This advantage is due to the fundamental interaction mechanism of the incident therapeutic protons with the patient, which produces a characteristic dose-distribution unique only to protons. Unlike photons, the entire proton beam is absorbed within the patent and the dose-distribution's maximum occurs near the end of the proton's path. Protons deliver less dose on the skin and intervening tissues, tighter dose conformality to the disease site, as well as no dose past the target volume, sparring healthy tissue distally in the patient. Current research in proton therapy is geared towards minimizing proton range uncertainty and monitoring in-vivo the location of the proton's path. Monitoring the beam's path serves also to verify which healthy structures/tissues were irradiated and whether the target volume has met the prescription dose. Among the many techniques used for in-vivo proton monitoring, the technique based on the emitted secondary particles, specifically the Prompt Gamma (PG) method, can be used for clinical implementation. This work focuses on developing a radiation detector system for using the PG method by investigating the characterizing the secondary particle field emitted from plastic and water phantoms as well as a radiation detector based on glass materials that exploits the Cherenkov phenomenon.

  9. SAS-2 observations of celestial diffuse gamma radiation above 30 MeV

    NASA Technical Reports Server (NTRS)

    Thompson, D. J.; Fichtel, C. E.; Kniffen, D. A.; Hartman, R. C.

    1974-01-01

    The small astronomy satellite, SAS-2, used a 32-deck magnetic core digitized spark chamber to study gamma rays with energies above 30 MeV. Data for four regions of the sky away from the galactic plane were analyzed. These regions show a finite, diffuse flux of gamma rays with a steep energy spectrum, and the flux is uniform over all the regions. Represented by a power law, the differential energy spectrum shows an index of 2.5 + or - 0.4. The steep SAS-2 spectrum and the lower energy data are reasonably consistent with a neutral pion gamma-ray spectrum which was red-shifted (such as that proposed by some cosmological theories). It is concluded that the diffuse celestial gamma ray spectrum observed presents the possibility of cosmological studies and possible evidence for a residual cosmic ray density, and supports the galactic superclusters of matter and antimatter remaining from baryon-symmetric big bang.

  10. Orbital Observatory GLAST - New Step in the Study of Cosmic Gamma-Radiation

    NASA Technical Reports Server (NTRS)

    Moiseev, A. A.

    2008-01-01

    The new Gamma-ray Large Area Space Telescope (GLAST) is scheduled for launch in the middle of 2008. It contains the high energy gamma-ray telescope LAT (Large Area Telescope) which covers the energy range from 20 MeV to >300 GeV and the GMB (GLAST Burst Monitor), covering 8 keV - 30 MeV energy range. The GLAST science objectives include understanding the mechanism of charged particle acceleration in active galactic nuclei, pulsars and supernova remnants, determining the nature of the still-unidentified EGRET sources, detailed study of gamma-ray diffuse emission, high-energy emission from gamma-ray bursts and transient sources, and probing dark matter. A brief overview of the mission is given.

  11. Extending the response of the sum coincidence spectrometer to multiple gamma radiation cascades

    E-print Network

    Helton, Victor Dean

    1964-01-01

    be limited by light collection problems. For precision gamma-ray spectroscopy, high resolution out-weighs the disadvantage of low detection efficiency. The three-crystal scintillation spectrometer, developed by Maieschein' and Bair5, gives higher counting... BIBLIOGRAPHY ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ o ~ 52 LIST OF FIGURES Figure Page 1. The Sum Coincidence Spectrometer . ~ ~ ~ ~ ~ ~ 11 2. The Three Gamma-Ray Cascade . . . . . . . . . 14 3 The Coincidence-Sum Spectrometer . . . . . . . 20 4, ~ 5...

  12. Indoor and Outdoor in Situ High-Resolution Gamma Radiation Measurements in Urban Areas of Cyprus

    Microsoft Academic Search

    E. Svoukis; H. Tsertos

    2006-01-01

    In situ, high-resolution, gamma-ray spectrometry of a total number of 70 outdoor and 20 indoor representative measurements were performed in preselected, common locations of the main urban areas of Cyprus. Specific activities and gamma absorbed dose rates in air due to the naturally occurring radionuclides of Th-232 and U-238 series, and K-40 are determined and discussed. Effective dose rate to

  13. Discovery of VHE Gamma Radiation from IC443 with the MAGIC Telescope

    Microsoft Academic Search

    E. ALIU; H. ANDERHUB; P. ANTORANZ; A. ARMADA; C. BAIXERAS; H. BARTKO; D. BASTIERI; J. K. BECKER; W. BEDNAREK; K. BERGER; C. BIGONGIARI; A. BILAND; P. BORDAS; T. BRETZ; I. BRITVITCH; M. CAMARA; E. CARMONA; A. CHILINGARIAN; J. A. COARASA; S. COMMICHAU; J. L. CONTRERAS; V. DANIELYAN; F. DAZZI; C. DELGADO; D. DORNER; M. DORO; M. ERRANDO; M. FAGIOLINI; D. FERENC; E. FERNÁNDEZ; R. FIRPO; M. V. FONSECA; M. FUCHS; N. GALANTE; R. J. GARCÍA-LÓPEZ; M. GARCZARCZYK; M. GAUG; M. GILLER; F. GOEBEL; D. HAKOBYAN; M. HAYASHIDA; T. HENGSTEBECK; A. HERRERO; D. HÖHNE; C. C. HSU; P. JACON; T. JOGLER; R. KOSYRA; D. KRANICH; R. KRITZER; A. LAILLE; E. LINDFORS; S. LOMBARDI; F. LONGO; J. LÓPEZ; M. LÓPEZ; E. LORENZ; P. MAJUMDAR; G. MANEVA; K. MANNHEIM; O. MANSUTTI; M. MARIOTTI; M. MARTÍNEZ; D. MAZIN; C. MERCK; M. MEUCCI; M. MEYER; J. M. MIRANDA; R. MIRZOYAN; S. MIZOBUCHI; A. MORALEJO; D. NIETO; K. NILSSON; J. NINKOVIC; N. OTTE; I. OYA; D. PANEQUE; M. PANNIELLO; R. PAOLETTI; M. PASANEN; D. PASCOLI; F. PAUSS; R. PEGNA; M. PERSIC; L. PERUZZO; A. PICCIOLI; E. PRANDINI; N. PUCHADES; W. RHODE; M. RIBÓ; J. RICO; M. RISSI; A. ROBERT; A. SAGGION; T. SAITO; A. SÁNCHEZ; P. SARTORI; V. SCALZOTTO; V. SCAPIN; R. SCHMITT; T. SCHWEIZER; M. SHAYDUK; K. SHINOZAKI; N. SIDRO; A. SILLANPÄÄ; D. SOBCZYNSKA; A. STAMERRA; L. TAKALO; P. TEMNIKOV; D. TESCARO; M. TESHIMA; D. F. TORRES; N. TURINI; H. VANKOV; R. M. WAGNER; T. WIBIG; W. WITTEK; R. ZANIN; J. ZAPATERO

    2007-01-01

    We report the detection of a new source of very high energy (VHE, E_gamma >=\\u000a100GeV) gamma-ray emission located close to the Galactic Plane, MAGIC\\u000aJ0616+225, which is spatially coincident with SNR IC443. The observations were\\u000acarried out with the MAGIC telescope in the periods December 2005 - January\\u000a2006 and December 2006 - January 2007. Here we present results

  14. Effect of hyperthermia on the radiation response of the mouse jejunum. [Whole-body. gamma. irradiation

    Microsoft Academic Search

    O. R. Merino; L. J. Peters; K. A. Mason; H. R. Withers

    1978-01-01

    The experiments reported show that the effect of radiation on the gut mucosa may be significantly enhanced by moderate hyperthermia (41 to 44°C) that is applied for 30 min before or after irradiation. The predominant effect of combined heat and radiation was to displace the radiation survival curves of jejunal crypt stem cells to the left without a significant change

  15. Detection of energetic particles and gamma rays General radiation detection concepts

    E-print Network

    Peletier, Reynier

    detectors · ionisation · proportional · Geiger #12;3 A generic radiation detector assumptions: · individual of radiation detector sensitive volume pulse shape depends on detector type and eventual electronics #12 detection concepts ­ pulse mode operation ­ energy spectrum ­ detector efficiency ­ timing · Radiation

  16. The beta calibration of radiation survey instruments at protection levels

    Microsoft Academic Search

    B. Owen

    1972-01-01

    Beta ray dose rates at protection levels from sources of 90Sr+90Y, 204Tl and 147Pm have been measured in units of 'millirads in air per hour' with a statistical uncertainty of +or-2% or less, and an estimated uncertainty of +or-4% or less, using a specially designed thin-walled, parallel-plate ionization chamber. The measured dose rates from these sources have been used to

  17. Measurement magnetic field level of radiated emissions from military equipment

    Microsoft Academic Search

    R. Przesmycki; L. Nowosielski; M. Wnuk; R. Kubacki

    2010-01-01

    The article concerns problems of electromagnetic compatibility of military equipment. Its goal is to present a sample application of position and methodology of measurements concerning measurement level of magnetic induction of interference in the frequency ranging from 30Hz to 100kHz, generated by equipment, sets of devices and such components as feeder cables, control, signal, aerial and connection cables(ducts) between components

  18. Wear of nano-TiO2/UHMWPE composites radiated by gamma ray under physiological saline water lubrication.

    PubMed

    Xiong, Dangsheng; Lin, Jianming; Fan, Dongli; Jin, Zhongmin

    2007-11-01

    Nano-TiO(2)/UHMWPE composites were prepared by hot press procedure, and then radiated by gamma ray in dose of 120 kGy, 250 kGy and 500 kGy. The hardness of the composites was initially determined. Subsequently the wear against a CoCrMo alloy counterface were tested in a knee simulator under physiological saline lubrication. The morphologies of the worn surfaces were examined with optical microscope. The structure of the samples was determined by IR and XRD. The results showed that the wear rate of the composite UHMWPE decreased when filled with proper amount of nano-TiO(2) and with the radiation dose. PMID:17665107

  19. Effects of gamma radiation on development, sterility, fecundity, and sex ratio of Dermanyssus gallinae (DeGeer) (Acari: Dermanyssidae)

    SciTech Connect

    Entrekin, D.L.; Oliver, J.H. Jr.; Pound, J.M.

    1987-06-01

    Protonymphal Dermanyssus gallinae were irradiated with 0.50, 0.75, 1.0, 3.0, and 6.0 krad of gamma radiation and subsequently monitored regarding their developmental, feeding, and mating success. Also, sex ratios of adults treated as protonymphs were recorded as were sex ratios of embryos and F1 adults produced by these adults. Doses up to 1.0 krad did not prevent development of treated protonymphs to the adult stage or stop mating. Three krad reduced the number of treated protonymphs attaining adulthood and 6.0-krad treatment prevented all mites from developing to the adult stage. Egg (embryo) production was normal for mites treated with 0.50 krad, but significantly curtailed by doses of 0.75 krad and greater. Radiation doses used in this study did not appear to affect the normal variable sex ratios observed in untreated mites.

  20. Analysis of White Blood Cell Counts in Mice after Gamma- or Proton-Radiation Exposure

    PubMed Central

    Maks, Casey J.; Wan, X. Steven; Ware, Jeffrey H.; Romero-Weaver, Ana L.; Sanzari, Jenine K.; Wilson, Jolaine M.; Rightnar, Steve; Wroe, Andrew J.; Koss, Peter; Gridley, Daila S.; Slater, James M.; Kennedy, Ann R.

    2013-01-01

    In the coming decades human space exploration is expected to move beyond low-Earth orbit. This transition involves increasing mission time and therefore an increased risk of radiation exposure from solar particle event (SPE) radiation. Acute radiation effects after exposure to SPE radiation are of prime importance due to potential mission-threatening consequences. The major objective of this study was to characterize the dose–response relationship for proton and ? radiation delivered at doses up to 2 Gy at high (0.5 Gy/min) and low (0.5 Gy/h) dose rates using white blood cell (WBC) counts as a biological end point. The results demonstrate a dose-dependent decrease in WBC counts in mice exposed to high- and low-dose-rate proton and ? radiation, suggesting that astronauts exposed to SPE-like radiation may experience a significant decrease in circulating leukocytes. PMID:21476859